WO2023204068A1

WO2023204068A1 - Adhesive composition, cured product of said adhesive composition, and method for producing said adhesive composition

Info

Publication number: WO2023204068A1
Application number: PCT/JP2023/014492
Authority: WO
Inventors: 豊一鈴木; 豪明荒井; 正仁古海; 仁下間; 卓也小峰
Original assignee: Ａｇｃ株式会社
Priority date: 2022-04-22
Filing date: 2023-04-10
Publication date: 2023-10-26

Abstract

Provided are: an adhesive composition which exhibits good film formability and excellent lightfastness, breaking strength and breaking elongation; a cured product of said adhesive composition; and a method for producing said adhesive composition. This adhesive composition contains an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol. The polyether polycarbonate polyol has three or more terminal groups per molecule and has a constituent unit derived from an initiator, a constituent unit derived from a cyclic ether and a constituent unit derived from carbon dioxide. The proportion of the constituent unit derived from carbon dioxide in the molecule is 10-30 mass%.

Description

Adhesive composition, cured product of the adhesive composition, and method for producing the adhesive composition

The present invention relates to an adhesive composition, a cured product of the adhesive composition, and a method for producing the adhesive composition.

BACKGROUND ART In the fields of automobiles, building materials, ships, aircraft, etc., various structural adhesives for bonding materials such as resins, glass, metals, and ceramics and coating agents for these materials have been studied. The structural adhesives and coating agents are required to have light resistance, good breaking strength, and good breaking elongation.
For example, U.S. Pat. A poly(propylene carbonate) polyol composition is disclosed having an average molecular weight (Mn) and greater than 95% carbonate bonding between adjacent monomer units in the polycarbonate chain, and has improved lightfastness, breaking strength, and breaking elongation. It is said to be excellent in
Patent Document 2 discloses a polyol compound containing a main ingredient including a urethane prepolymer having an isocyanate group, and a specific polyol compound having ethylene oxide at the terminal and three active hydrogen-containing groups in one molecule, that is, it is trifunctional. A two-component urethane adhesive composition having a curing agent and a curing agent is disclosed, and is said to have excellent initial adhesion and long-term adhesion.

Special table number 2013-543929 International Publication No. 2019/240046

However, the poly(propylene carbonate) polyol composition described in Patent Document 1 has a problem of high viscosity and low thermal stability, and furthermore, has a problem of low film formability when made into a urethane resin. be. Furthermore, the two-component urethane adhesive composition described in Patent Document 2 has insufficient light resistance, and there is room for improvement.

The present invention solves these problems, and provides an adhesive composition that has good film formability and excellent light resistance, breaking strength, and elongation at break of a cured product, and a cured product of the adhesive composition. Another object of the present invention is to provide a method for producing the adhesive composition.

The present inventors conducted intensive studies to solve the above problems, and found that an adhesive composition containing an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol having a specific structure solved the above problems. They discovered that it is possible to do so, and completed the present invention.
That is, the present invention is as follows.
[1] An adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol,
The polyether polycarbonate polyol has three or more terminal groups in one molecule, and has a structural unit derived from an initiator, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide, and An adhesive composition in which the proportion of the structural unit derived from carbon dioxide in one molecule is 10 to 30% by mass.
[2] The adhesive composition according to [1] above, wherein the polyether polycarbonate polyol has a molecular weight in terms of hydroxyl value of 500 to 20,000.
[3] The polyether polycarbonate polyol has a molecular weight distribution (Mw/Mn) expressed by the ratio of weight average molecular weight (Mw) and number average molecular weight (Mn) of 1.05 to 3.00, [1] ] or the adhesive composition according to [2].
[4] The proportion of structural units in which the structural units derived from the carbon dioxide, the structural units derived from the cyclic ether, and the structural units derived from the carbon dioxide are chained in this order in the polyether polycarbonate polyol is 2% by mass. The adhesive composition according to any one of [1] to [3] above.
[5] The structural unit derived from the cyclic ether that the polyether polycarbonate polyol has is at least one structural unit selected from the group consisting of structural units derived from ethylene oxide and structural units derived from propylene oxide. , the adhesive composition according to any one of [1] to [4] above.
[6] The adhesive composition according to any one of [1] to [5] above, wherein the terminal group of the polyether polycarbonate polyol is a hydroxyl group.
[7] The adhesive according to any one of [1] to [6] above, wherein the molar ratio of the isocyanate groups in the isocyanate group-terminated urethane prepolymer to the hydroxyl groups in the polyether polycarbonate polyol is 80 or more and 150 or less. Composition.
[8] The adhesive composition according to any one of [1] to [7] above, wherein the content of the polyether polycarbonate polyol is 10 to 70% by mass based on the total amount of the adhesive composition.
[9] The adhesive composition according to any one of [1] to [8] above, further containing a chain extender.
[10] A cured product of the adhesive composition according to any one of [1] to [9] above.
[11] A method for producing an adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol, comprising:
In the presence of a catalyst, an initiator having three or more active hydrogen-containing groups in one molecule, a cyclic ether, and carbon dioxide are polymerized to obtain a polyether polycarbonate polyol, and the polyether polycarbonate polyol and isocyanate groups are polymerized. Mix the terminal urethane prepolymer,
A method for producing an adhesive composition, wherein the proportion of structural units derived from carbon dioxide in one molecule of the polyether polycarbonate polyol is 10 to 30% by mass.
[12] The method for producing an adhesive composition according to [11] above, wherein the catalyst includes at least one selected from the group consisting of a composite metal cyanide complex catalyst and a metal salen complex catalyst.
[13] The isocyanate group-terminated urethane prepolymer is prepared by reacting a polyol and a polyisocyanate compound such that a molar ratio of 100 times the isocyanate group in the polyisocyanate compound to the hydroxyl group in the polyol is 110 or more and 600 or less. The method for producing the adhesive composition according to [11] or [12] above, which is a reaction product.

According to the present invention, an adhesive composition having good film formability and excellent light resistance, breaking strength, and breaking elongation of a cured product, a cured product of the adhesive composition, and a method for producing the adhesive composition can be provided.

The present invention will be explained in detail below.
In this specification, any of the preferable ones can be adopted, and combinations of the preferable ones can be said to be more preferable.
Furthermore, in this specification, the expression "XX to YY" means "XX to YY".
Moreover, in this specification, the lower limit and upper limit described in stages for preferred numerical ranges (for example, ranges of content, etc.) may be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit (10)" and "more preferable upper limit (60)" are combined to become "10 to 60". You can also do that. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.
Furthermore, in this specification, the term "unit" constituting a polymer means an atomic group formed by polymerization of monomers.
Furthermore, in this specification, the term "terminal group" includes not only a functional group at the end of the main chain of a polymer, but also a functional group at the end of a branched chain equivalent to the main chain.

<Adhesive composition>
The present invention is an adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol, wherein the polyether polycarbonate polyol has three or more end groups in one molecule and is derived from an initiator. An adhesive having a structural unit derived from a cyclic ether, a structural unit derived from carbon dioxide, and a proportion of the structural unit derived from carbon dioxide in one molecule is 10 to 30% by mass. It is a drug composition.
The adhesive composition of the present invention has good film formability, and the cured product thereof has excellent light resistance, breaking strength, and breaking elongation. Each component will be explained below.

[Isocyanate group-terminated urethane prepolymer]
The isocyanate group-terminated urethane prepolymer is a molecular chain obtained by reacting a polyisocyanate compound with a compound having two or more active hydrogen-containing groups in one molecule (hereinafter referred to as "active hydrogen compound"). is a compound having an isocyanate group at at least a portion of its terminal end.
The isocyanate group-terminated urethane prepolymer is obtained by reacting a polyisocyanate compound and an active hydrogen compound such that the isocyanate groups are in excess of the active hydrogen-containing groups. Examples of the active hydrogen-containing group include a hydroxyl group, an amino group, and an imino group.
Examples of such active hydrogen compounds include polyols having two or more hydroxyl groups in one molecule and polyamines having two or more amino groups in one molecule, with polyols being preferred.

(polyol)
The number average molecular weight (Mn) of the polyol is 1,000 to 50, from the viewpoint that the viscosity of the isocyanate group-terminated urethane prepolymer obtained by reaction with a polyisocyanate compound has appropriate fluidity at room temperature (25°C). 000 is preferred, and 3,000 to 30,000 is more preferred. In the present invention, the Mn is a value obtained by the same method as the method for measuring Mn of polyether polycarbonate polyol, which will be described later. When the Mn of the polyol is within the above range, the cured product obtained by curing the adhesive composition of the present invention tends to have good light resistance, breaking strength, and breaking elongation.

The molecular weight, skeleton, etc. of the polyol are not particularly limited as long as it is a compound having two or more hydroxyl groups. Examples of polyols include polyether polyols, polyester polyols, polymer polyols, poly(meth)acrylic polyols, polycarbonate polyols, castor oil polyols, and polyolefin polyols, including [0016] to [0028] of JP 2020-37689A. ] can be used without particular limitation. These may be used alone or in combination of two or more.
Furthermore, as the polyol, it is also possible to use a polymer polyol in which a polymer having units based on (meth)acrylate monomers is dispersed in a polyether polyol. The polymer polyol may be a commercially available product, such as the "Ultiflow (registered trademark)" series, the "Sharpflow (registered trademark)" series (manufactured by Sanyo Chemical Industries, Ltd.), and the "Excenol (registered trademark)". ” series (manufactured by AGC Corporation).
Furthermore, a polyether polycarbonate polyol having three or more terminal groups in one molecule, which will be described later, may also be used.
In this specification, (meth)acrylic means acrylic and/or methacryl, and (meth)acrylate means acrylate and/or methacrylate.

(Polyisocyanate compound)
The polyisocyanate compound used for producing the isocyanate group-terminated urethane prepolymer is an organic compound having two or more isocyanate groups in one molecule. The number of isocyanate groups in one molecule is preferably 2 to 4. The polyisocyanate compounds may be used alone or in combination of two or more.
Examples of the polyisocyanate compound include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, and lysine. Linear or branched aliphatic diisocyanate compounds such as diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate;
norbornane diisocyanate (NBDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, Alicyclic diisocyanate compounds such as dicyclohexylmethane diisocyanate (H ₁₂ MDI);
Tolylene diisocyanate (TDI), 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, polymethylene Polyphenylene polyisocyanate, xylylene diisocyanate, α,α,α',α'-tetramethylxylylene diisocyanate, 4,4'-dibenzyl diisocyanate, toridine diisocyanate, 1,5-naphthalene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane Aromatic diisocyanate compound of diisocyanate;
Isocyanurate-modified products of the above-mentioned diisocyanate compounds; Biuret-modified products of the above-mentioned diisocyanate compounds; Allophanate-modified products of the above-mentioned diisocyanate compounds; Carbodiimide-modified products of the above-mentioned diisocyanate compounds; Tri- or higher-functional isocyanate group-terminated urethane prepolymers (adduct modified products) obtained by reacting with polyols having hydroxyl groups; water-dispersible polyisocyanate compounds such as water-dispersible isocyanates and block isocyanates; Examples include polyisocyanate compounds having three or more isocyanate groups in one molecule.

Examples of commercially available modified isocyanurate products include Duranate TPA-100, Duranate TKA-100 (all manufactured by Asahi Kasei Corporation), and Coronate HX (manufactured by Tosoh Corporation).
Commercially available products of modified biuret include, for example, Duranate 24A-100 and Duranate 22A-75P (both manufactured by Asahi Kasei Corporation).
Commercially available trifunctional or higher isocyanate group-terminated urethane prepolymers include, for example, Coronate L, Coronate L-55E, and Coronate L-45E (all manufactured by Tosoh Corporation).
Commercially available water-dispersed isocyanates include, for example, Duranate WB40-100, Duranate WB40-80D, Duranate WT20-100, Duranate WL70-100, Duranate WE50-100, Duranate WR80-70P (all manufactured by Asahi Kasei Corporation), Examples include Aquanate 105, Aquanate 130, Aquanate 140, Aquanate 200, and Aquanate 210 (all manufactured by Tosoh Corporation).
Commercially available blocked isocyanates include, for example, SU-268A, NBP-211, Meikanate CX, Meikanate TP-10, and DM-6400 (all manufactured by Meisei Chemical Industry Co., Ltd.); WM44-L70G (manufactured by Asahi Kasei Corporation); Aqua BI200, Aqua BI220 (both manufactured by Baxenden Chemicals); Takelac W, Takelac WPB (both manufactured by Mitsui Chemicals, Inc.); Burnock (manufactured by DIC Corporation); and Elastron (manufactured by Dai-ichi Kogyo Co., Ltd.).

The content of isocyanate groups in the polyisocyanate compound is determined from the viewpoint of obtaining an adhesive composition that has excellent reactivity of the polyisocyanate compound with respect to the active hydrogen compound and has excellent light resistance, breaking strength, and elongation of the cured product. Preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass. It is as follows.
As the polyisocyanate compound containing an isocyanate group in the above-mentioned preferable range, specifically, an aliphatic diisocyanate compound, an alicyclic diisocyanate compound, an aromatic diisocyanate compound are preferable, and MDI (isocyanate group content: 33.6% by mass), Polymeric MDI (isocyanate group content 31.0% by mass), Crude MDI (mixture of MDI and triphenylmethane triisocyanate, isocyanate group content 30.0-32.6% by mass), IPDI (isocyanate group content 37.8% by mass) %).

When obtaining the isocyanate group-terminated urethane prepolymer, the molar ratio of the isocyanate groups in the polyisocyanate compound to the hydroxyl groups in the polyol (isocyanate groups/hydroxyl groups) is preferably 100 times or more and 600 or less.
The molar ratio is preferably 120 or more, more preferably 125 or more, even more preferably 130 or more, and is preferably 500 or less, more preferably 450 or less, still more preferably 400 or less. When the molar ratio is within the preferable range, it is possible to produce an isocyanate group-terminated urethane prepolymer having an appropriate molecular chain length, thereby further improving productivity. Moreover, it is preferable from the viewpoint of further improving the light resistance, breaking strength, and breaking elongation of a cured product obtained by curing the adhesive composition of the present invention.

The isocyanate group-terminated urethane prepolymer can be produced by reacting a polyol and a polyisocyanate compound.
A catalyst may be used, if necessary, in the production of the isocyanate group-terminated urethane prepolymer. Examples of the catalyst include tertiary amine compounds; tin compounds; and non-tin compounds. One type of catalyst can be used alone or two or more types can be used in combination.
Examples of the tertiary amine compound include triethylamine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).
Examples of tin-based compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, and tributyltin. Examples include tin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.
Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. ; Iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; Cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; Zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate; Examples include zirconium compounds such as zirconium naphthenate.
When a catalyst is used, the amount of the catalyst used is preferably 0.001 parts by mass or more, more preferably 0.002 parts by mass or more, and even more preferably 0. The amount is .003 parts by mass or more, and preferably 1.0 parts by mass or less, more preferably 0.2 parts by mass or less, and still more preferably 0.05 parts by mass or less.

A solvent may be used, if necessary, in the production of the isocyanate group-terminated urethane prepolymer.
Examples of the solvent include ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; and aromatic hydrocarbons such as toluene and xylene. One type of solvent can be used alone or two or more types can be used in combination.
When a solvent is used, the amount of the solvent used is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, based on the total of 100 parts by mass of the polyol and the polyisocyanate compound. The content is preferably 500 parts by mass or less, more preferably 450 parts by mass or less, and even more preferably 400 parts by mass or less.

Examples of the method for producing the isocyanate group-terminated urethane prepolymer include the following methods.
Production method 1: A method in which a polyol, a polyisocyanate compound, an arbitrary catalyst, and an arbitrary solvent are charged all at once. Production method 2: A polyol, an arbitrary catalyst, and an arbitrary solvent are introduced, and the polyisocyanate compound is added dropwise thereto. Method In the case of production method 2, the low molecular weight components in the raw materials are preferentially reacted, the molecular weight distribution can be narrowed, and the reaction can be easily controlled.

The reaction temperature is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 65°C or higher, and lower than 100°C, more preferably 95°C or lower, even more preferably 85°C or lower. When the reaction temperature is within the above range, side reactions other than the urethane reaction can be easily suppressed, making it easier to obtain the desired isocyanate group-terminated urethane prepolymer.

After the reaction is completed, a reaction terminator may be added to inactivate the catalyst. Examples of the reaction terminator include acetylacetone. Two or more types of reaction terminators may be used in combination.

The content of the isocyanate group-terminated urethane prepolymer is preferably 30 to 90% by mass, more preferably 35 to 80% by mass, and even more preferably 40 to 70% by mass based on the total amount of the adhesive composition. . When the content of the isocyanate group-terminated urethane prepolymer is at least the lower limit, the cured product obtained by curing the adhesive composition of the present invention has good breaking strength, and when it is at most the upper limit, A cured product obtained by curing the adhesive composition of the present invention has good elongation properties.

[Polyether polycarbonate polyol]
The polyether polycarbonate polyol has three or more terminal groups in one molecule, and has a structural unit derived from an initiator, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide.
If the polyether polycarbonate polyol has less than three terminal groups in one molecule, the light resistance, breaking strength, and elongation of the cured product obtained by curing the adhesive composition of the present invention may decrease. . From such a viewpoint, it is preferable that the polyether polycarbonate polyol has four or more terminal groups in one molecule. In addition, polyether polycarbonate polyol can suppress increase in viscosity caused by hydrogen bonding of hydroxyl groups, and from the viewpoint of ease of handling when curing the adhesive composition of the present invention and ease of coating, 1 It is preferable to have 10 or less terminal groups in the molecule, and more preferably 8 or less.

The terminal group that the polyether polycarbonate polyol has three or more in one molecule is preferably an active hydrogen-containing group. Examples of the active hydrogen-containing group include a hydroxyl group, a carboxy group, and an amino group having a hydrogen atom bonded to a nitrogen atom. The active hydrogen-containing group is preferably a hydroxyl group.

The molecular weight in terms of hydroxyl value of the polyether polycarbonate polyol is preferably 500 to 20,000, more preferably 700 to 15,000, still more preferably 800 to 10,000, even more preferably 900 to 8 ,000. When the molecular weight in terms of hydroxyl value is 500 or more, the elongation at break of a cured product obtained by curing the adhesive composition of the present invention becomes more excellent, and the molecular weight in terms of hydroxyl value is 20,000 or less. Thus, the cured product obtained by curing the adhesive composition of the present invention has better light resistance, breaking strength, and breaking elongation.
In addition, the molecular weight in terms of hydroxyl value of polyether polycarbonate polyol is obtained by applying the hydroxyl value calculated based on JIS K 1557 (2007) to the formula [56,100/(hydroxyl value)] x (number of functional groups). It is the molecular weight calculated using the value. Specifically, it is measured by the method described in Examples below.

The number average molecular weight (Mn) of the polyether polycarbonate polyol is preferably 750 to 30,000, more preferably 1,000 to 22,000, even more preferably 1,200 to 15,000, and more preferably More preferably, it is 1,300 to 12,000. When the number average molecular weight is 750 or more, the elongation at break of a cured product obtained by curing the adhesive composition of the present invention becomes more excellent, and when the number average molecular weight is 30,000 or less, A cured product obtained by curing the adhesive composition of the present invention has better light resistance, breaking strength, and breaking elongation.
The molecular weight distribution (Mw/Mn) expressed by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyether polycarbonate polyol is the light resistance of the cured product obtained by curing the adhesive composition of the present invention. , from the viewpoint of better breaking strength and breaking elongation, preferably from 1.05 to 3.00, more preferably from 1.07 to 2.50, still more preferably from 1.10 to 2.00. .

The Mn and molecular weight distribution of the polyether polycarbonate polyol are values obtained by measurement by the method described below.
As a standard sample for molecular weight measurement, several types of monodisperse polystyrene with different degrees of polymerization were measured using a commercially available GPC measurement device (HLC-8320GPC, manufactured by Tosoh Technosystems Co., Ltd.), and the relationship between the molecular weight of polystyrene and retention time was determined. A calibration curve was created based on the relationship, and the measurement sample, polyether polycarbonate polyol, was diluted to 0.5% by mass with tetrahydrofuran and passed through a filter with a pore size of 0.5 μm. Measure using a measuring device. Mn and Mw of the measurement sample are determined by computer analysis of the GPC spectrum of the measurement sample using the calibration curve.
The molecular weight distribution is a value calculated from the above Mw and Mn, and is the ratio of Mw to Mn ("Mw/Mn").

The proportion of structural units derived from carbon dioxide (CO ₂ proportion) in one molecule of the polyether polycarbonate polyol is 10 to 30% by mass. If the proportion of the structural unit derived from carbon dioxide is less than 10% by mass, the light resistance, breaking strength, and breaking elongation of the cured product obtained by curing the adhesive composition of the present invention may decrease. When the proportion of the structural units derived from carbon dioxide exceeds 30% by mass, the viscosity becomes too high, resulting in poor workability, and there is a risk that the film formability of the adhesive composition of the present invention may deteriorate. From this point of view, the proportion of the structural units derived from carbon dioxide is preferably 11 to 28% by mass, more preferably 12 to 26% by mass.
Note that the proportion of the structural units derived from carbon dioxide is measured by the method described in Examples below.

A structural unit in which a structural unit derived from carbon dioxide, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide in a polyether polycarbonate polyol are chained in this order (hereinafter also referred to as a CO ₂ -AO-CO ₂ chain) The proportion of is preferably 2% by mass or more, more preferably 2% by mass, from the viewpoint of improving the light resistance, breaking strength, and elongation at break of the cured product obtained by curing the adhesive composition of the present invention. The content is .5% by mass or more, more preferably 2.6% by mass or more. Further, the proportion of CO ₂ -AO-CO ₂ chains is preferably 50% by mass or less from the viewpoint of further improving the thermal stability of the polyether polycarbonate polyol and the film formability of the adhesive composition of the present invention, It is more preferably 40% by mass or less, still more preferably 30% by mass or less, even more preferably 20% by mass or less.

Ratio of structural units derived from cyclic ether, structural units derived from cyclic ether, and structural units in which structural units derived from cyclic ether are chained in this order (hereinafter also referred to as AO-AO-AO chain) in polyether polycarbonate polyol is preferably 30 to 80% by mass, more preferably 35 to 75% by mass, still more preferably 40 to 75% by mass, even more preferably 40% by mass, from the viewpoint of further exerting the effects of the present invention. ~72% by mass.

A structural unit in which a structural unit derived from a cyclic ether, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide are chained in this order in polyether polycarbonate polyol (hereinafter also referred to as AO-AO-CO ₂ chain). The proportion is preferably 8 to 60% by mass, more preferably 15 to 55% by mass, and still more preferably 20 to 50% by mass, from the viewpoint of further exerting the effects of the present invention.

The proportion of CO ₂ -AO-CO ₂ chains, the proportion of AO-AO-AO chains, and the proportion of AO-AO-CO ₂ chains in the polyether polycarbonate polyol are, for example, when the cyclic ether AO is propylene oxide PO, The polyether polycarbonate polyol is dissolved in deuterated chloroform to a concentration of 10% by mass, and ¹ H-NMR is measured using an NMR device with a resolution of 400 MHz. From the obtained results, the 3H peak (δ1.34 ppm) derived from the methyl group of propylene oxide PO as a cyclic ether AO with both ends adjacent to carbonate, and the 3H peak derived from the methyl group of PO with one end adjacent to carbonate and the other end adjacent to PO. (δ1.29ppm), which can be calculated from the area ratio of the 3H peak derived from the methyl group of PO (δ1.14ppm), which has PO adjacent to both ends. Specifically, it can be measured by the method described in Examples.
Note that the ratio of the structural units derived from carbon dioxide described above can be calculated based on the area ratio.

The total content of the structural units derived from the initiator, the structural units derived from the cyclic ether, and the structural units derived from carbon dioxide in the polyether polycarbonate polyol is preferably 80% by mass or more, more preferably 90% by mass or more. , more preferably 95% by mass or more, and may be 100% by mass. It may consist only of structural units derived from an initiator, structural units derived from a cyclic ether, and structural units derived from carbon dioxide.

(initiator)
The initiator constituting the structural unit derived from the initiator contained in the polyether polycarbonate polyol is used from the viewpoint of making the cured product obtained by curing the adhesive composition of the present invention excellent in light resistance, breaking strength, and breaking elongation. Therefore, it is preferable to have three or more active hydrogen-containing groups in one molecule. Examples of the active hydrogen-containing group include a hydroxyl group, a carboxy group, and an amino group having a hydrogen atom bonded to a nitrogen atom. The active hydrogen-containing group is preferably a hydroxyl group.
It is more preferable that the initiator has four or more active hydrogen-containing groups in one molecule, and can suppress increase in viscosity caused by hydrogen bonding of hydroxyl groups, and can be used to cure the adhesive composition of the present invention. From the viewpoint of ease of handling and ease of coating, it is preferable to have 10 or less, more preferably 8 or less.

In order to improve the light resistance of the cured product obtained by curing the adhesive composition of the present invention, the initiator preferably has a structural unit derived from a cyclic ether per molecule of 3.0 mol or less. The amount is more preferably 2.5 mol or less, still more preferably 2.0 mol or less, and may be 0.0 mol.
The initiator may be a polyol that does not have structural units derived from cyclic ethers.

When the initiator has a structural unit derived from a cyclic ether, the structural unit derived from the cyclic ether is a structural unit derived from ethylene oxide, from the viewpoint that the cured product obtained by curing the adhesive composition of the present invention becomes more flexible. units, structural units derived from propylene oxide are preferred.

The number average molecular weight (Mn) of the initiator is preferably 40 to 3,000, more preferably 40 to 2,000, even more preferably 55 to 2,000, even more preferably 60 to 1 ,500. In the present invention, the Mn is a value obtained by the same method as the method for measuring Mn of the polyether polycarbonate polyol described above. When the Mn of the initiator is within the above range, a wide range of initiators can be selected according to the required physical properties of a cured product using a polyol made of the present initiator, and a sufficient amount of CO ₂ can be introduced. .

Specific examples of the initiator include glycerin, polyglycerin, trimethylolethane, trimethylolpropane, diglycerin, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose, sorbitol, dextrose, fructose, sucrose, methylglucoside, and the above. Trivalent or higher polyhydric alcohols such as saccharides or derivatives thereof other than those described in . Regarding the above-mentioned initiators, various optical isomers are also included. Also included are polyether polyols having a molecular weight of 50 to 8,000 in terms of hydroxyl value, which are obtained by reacting these with a small amount of alkylene oxide.

(cyclic ether)
The cyclic ether constituting the structural unit derived from the cyclic ether of the polyether polycarbonate polyol has preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably It is 2 to 4. The carbon atoms forming the ring of the cyclic ether may have a substituent, and examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a halogen atom, and a hydroxyl group.

Examples of the cyclic ether include cyclic ethers having two carbon atoms forming a ring, such as ethylene oxide, propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. These may be used alone or in combination of two or more.

The structural units derived from the cyclic ether that the polyether polycarbonate polyol has are the structural units derived from ethylene oxide and the structural units derived from propylene oxide, from the viewpoint that the cured product obtained by curing the adhesive composition of the present invention becomes more flexible. The structural unit is preferably at least one type of structural unit selected from the group consisting of units, and more preferably a structural unit derived from propylene oxide.

As long as the polyether polycarbonate polyol has a structural unit derived from an initiator, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide, for example, a polyvalent polycarbonate polyol represented by the following general formula (X) can be used. Ether polycarbonate polyols may be mentioned.

In the general formula (X), W represents a q-valent organic group, q is 3 to 10, R ² represents a divalent hydrocarbon group having 2 to 10 carbon atoms, and m is 1 to 150. Yes, and n is 1 to 60. In addition, in general formula (X), a plurality of R ² may be the same or different, and a plurality of n may be the same number or different numbers, The plural m's may be the same number or may be different numbers.

In the general formula (X), for example, when q is 3, W represents a trivalent organic group, and the number of terminal hydroxyl groups in the general formula (X) is three.
Examples of the q-valent organic group include a q-valent aliphatic hydrocarbon group having 2 to 12 carbon atoms having an aliphatic chain; a q-valent alicyclic hydrocarbon group having 3 to 12 carbon atoms having an alicyclic structure; ; a q-valent aromatic hydrocarbon group having 6 to 24 carbon atoms having an aromatic ring structure; a q-valent heterocyclic group having a heterocyclic structure containing a heteroatom such as an oxygen atom, a nitrogen atom, a sulfur atom, and glycerin; Polyglycerin, trimethylolethane, trimethylolpropane, diglycerin, pentaerythritol, dipentaerythritol, tripentaerythritol glucose, sorbitol, dextrose, fructose, sucrose, methyl glucoside, and other sugars or derivatives thereof, etc. Examples include polyhydric alcohols having a valence of 3 or more. Regarding the above-mentioned initiators, various optical isomers are also included. Examples include residues obtained by removing the hydroxyl group from one selected from the group consisting of polyether polyols having a molecular weight in terms of hydroxyl value of 50 to 8,000 obtained by reacting these with a small amount of alkylene oxide. Among these, from the viewpoint of ease of polymerization of cyclic ether, the q-valent organic group is composed of trihydric or higher polyhydric alcohols, saccharides, and polyether polyols with a molecular weight of 50 to 8,000 in terms of hydroxyl value. A residue obtained by removing a hydroxyl group from one selected from the group consisting of glycerin, trimethylolpropane, diglycerin, pentaerythritol, dipentaerythritol, and sorbitol is preferred. groups are more preferred.
Note that these organic groups may further have a substituent. Examples of substituents that the organic group may have include a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, a carbonyl group, a formyl group, an ester group, an amide group, an alkoxy group, an alkylthio group, Examples include arylthio group, amino group, and silyl group.

The R ² is preferably a linear or branched alkylene group having 2 to 6 carbon atoms, more preferably a tetramethylene group, a propylene group, or an ethylene group, and still more preferably a propylene group or an ethylene group.

The above q is preferably 3 to 10, from the viewpoint of suppressing high viscosity caused by hydrogen bonding of hydroxyl groups, ease of handling when curing the adhesive composition of the present invention, and ease of coating. , more preferably 3 to 8, still more preferably 4 to 8.
The n is preferably 1 to 60, more preferably 2 to 55, and even more preferably 3 to 45, from the viewpoint of improving the breaking strength and breaking elongation of the cured product and improving light resistance. be.
The m is preferably 1 to 150, more preferably 2 to 135, and still more preferably 3 to 120, from the viewpoint of ease of handling due to lower viscosity of the polymer.

In addition, in the polyether polycarbonate polyol represented by the above general formula (X), there is a structure represented by (-OC(=O)-OC(CH ₃ )-CH ₂ -) _n next to W. is formed, and a structure represented by (-O-R ₂ -) _m is placed at one end of the structure represented by (-OC(=O)-OC(CH ₃ )-CH ² -) _n . However, the present invention is not limited to this. For example, a structure represented by (-OR ² -) _m may be formed next to W.
Furthermore, a structural unit of (-O-R ² -) may be inserted into the structure represented by (-OC(=O)-OC(CH ₃ )-CH ₂ -) _n , A structural unit (-OC(=O)-OC(CH ₃ )-CH ₂ -) may be inserted into the structure represented by ( ^-OR 2 -) _m .
Furthermore, when R ² in (-O-R ² -) _m is different, the structure represented by (-O-R ² -) _m may be either a random structure or a block structure. .

The hydroxyl value of the polyether polycarbonate polyol is preferably 8 mgKOH/g or more, more preferably 16 mgKOH/g or more, even more preferably 22 mgKOH/g or more, and preferably 900 mgKOH/g or less, more preferably 700 mgKOH/g or less. , more preferably 340 mgKOH/g or less. If the hydroxyl value of the polyether polycarbonate polyol is below the above-mentioned upper limit, the resulting cured adhesive composition tends to have better light resistance, breaking strength, and breaking elongation.
The hydroxyl value of the polyether polycarbonate polyol is a value measured and calculated according to method B of JIS K 1557-1:2007.

The viscosity of the polyether polycarbonate polyol at 25° C. is preferably 150,000 mPa·s or less, more preferably 120,000 mPa·s or less, and still more preferably 100,000 mPa·s or less. When the viscosity of the polyether polycarbonate polyol at 25° C. is below the above upper limit, the resulting cured adhesive composition tends to have better light resistance, breaking strength, and breaking elongation.
The viscosity of the polyether polycarbonate polyol at 25°C is a value measured using an E-type viscometer. Specifically, it is measured by the method described in the Examples below.

The content of the polyether polycarbonate polyol is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass, based on the total amount of the adhesive composition. When the content of the polyether polycarbonate polyol is at least the lower limit, the light resistance, breaking strength, and elongation at break of the resulting cured adhesive composition will be better, and the content is at most the upper limit. Thus, the cured product obtained by curing the adhesive composition of the present invention has better elongation at break.

[Production method of polyether polycarbonate polyol]
Polyether polycarbonate polyol is obtained by polymerizing an initiator having three or more active hydrogen-containing groups in one molecule, a cyclic ether, and carbon dioxide in the presence of a catalyst.
As the initiator, those explained in the section (Initiator) can be used, and as the cyclic ether, those explained in the section (Cyclic ether) can be used.
In addition, the ring-opening addition polymerization in the case of reacting two or more types of cyclic ethers with an initiator and carbon dioxide may be random polymerization, block polymerization, or a combination of random polymerization and block polymerization. It may be.

Examples of the catalyst include a composite metal cyanide complex catalyst (hereinafter sometimes referred to as "DMC catalyst") such as a TBA-based composite metal cyanide complex catalyst; a metal salen complex catalyst such as a cobalt salen catalyst; sodium hydroxide; Alkali catalysts such as potassium hydroxide and cesium hydroxide; Ziegler-Natta catalysts consisting of organoaluminum compounds and transition metal compounds; metal-coordination porphyrin catalysts as complexes obtained by reacting porphyrins; phosphazene catalysts; phosphazenium salts containing imino groups; Tris (Pentafluorophenyl)borane; a reduced Robson's type macrocyclic ligand catalyst (catalyst consisting of a reduced Robson's type Macrocyclic ligand) is preferably mentioned. These may be used alone or in combination of two or more.

Examples of DMC catalysts include zinc hexacyanocobaltate complexes whose ligand is t-butyl alcohol (hereinafter sometimes referred to as "TBA-DMC catalyst"), and ethylene glycol dimethyl ether (also referred to as "glyme") whose ligand is t-butyl alcohol. Examples include zinc hexacyanocobaltate complexes in which the ligand is diethylene glycol dimethyl ether (sometimes referred to as "diglyme"). These may be used alone or in combination of two or more.
Among these, the TBA-DMC catalyst is preferred from the viewpoints of higher activity during polymerization, narrower Mw/Mn of the polyether polycarbonate polyol, and lower viscosity.

Examples of metal salen complex catalysts include cobalt salen complexes, chromium salen complexes, and aluminum salen complexes described in Japanese Patent Publication No. 2012-500867, JP2015-129306A, and JP2015-28182A. These may be used alone or in combination of two or more.

The catalyst preferably contains at least one selected from the group consisting of a DMC catalyst and a metal salen complex catalyst, from the viewpoint of easily adjusting the carbon dioxide introduction rate in the polyether polycarbonate polyol to the range specified in the present invention. .
Further, the catalyst is preferably a DMC catalyst or a reduced Robson type macrocyclic ligand catalyst from the viewpoint of obtaining a random polymer polyether polycarbonate polyol.

The amount of the catalyst added is preferably as small as possible as long as it is the amount necessary for the polymerization of carbon dioxide and the ring-opening polymerization of the cyclic ether, and is preferably as small as possible based on 100 parts by mass of the obtained polyether polycarbonate polyol. The amount is 0.001 to 10 parts by weight, more preferably 0.002 to 5 parts by weight, and even more preferably 0.05 to 3 parts by weight.
The smaller the amount of the catalyst added, the smaller the amount of catalyst contained in the polyether polycarbonate polyol product. Thereby, the influence of the catalyst on the reactivity between the polyether polycarbonate polyol and the isocyanate group-terminated urethane prepolymer can be reduced, and costs can be reduced.

From the viewpoint of reactivity, the polymerization reaction is preferably carried out under a pressure of 0.1 to 15 MPa, more preferably carried out under a pressure of 0.2 to 10 MPa, and carried out under a pressure of 0.3 to 8 MPa. It is even more preferable.

The polymerization temperature of the polymerization reaction is preferably 30 to 180°C, more preferably 70 to 160°C, and still more preferably 80 to 140°C.
When the polymerization temperature is 30° C. or higher, carbon dioxide polymerization and ring-opening polymerization of cyclic ether can be reliably started, and when it is 180° C. or lower, a decrease in the polymerization activity of the catalyst can be suppressed.

The polymerization time of the polymerization reaction is preferably 2 to 18 hours, more preferably 2 to 14 hours, and even more preferably 2 to 10 hours.
When the polymerization time is 2 hours or more, the reaction performance is excellent, and when it is 18 hours or less, it is economical.

The amount of the cyclic ether to be charged is preferably 40.0 to 99.0 parts by mass, more preferably 45.0 to 98.0 parts by mass, and even more preferably is 50.0 to 97.0 parts by mass.
When the amount of the cyclic ether charged is within the above range, the viscosity of the resulting adhesive composition will not become too high, the workability during coating and curing will tend to be good, and the cured product of the adhesive composition will not become too high. Flexibility tends to be better.

The amount of carbon dioxide charged is preferably 0.05 to 40% by mass, more preferably 0.10 to 35% by mass, and even more preferably 1.15 to 30% by mass, based on the obtained polyether polycarbonate polyol. It is.
When the amount of carbon dioxide charged is within the above range, the light resistance and breaking strength of the cured product of the resulting adhesive composition tend to be better.

In the adhesive composition of the present invention, the isocyanate index, which represents 100 times the molar ratio (isocyanate group/hydroxyl group) of the isocyanate group in the isocyanate group-terminated urethane prepolymer to the hydroxyl group in the polyether polycarbonate polyol, is 80 or more and 150 or less. It is preferable that
The isocyanate index is preferably 85 or higher, more preferably 90 or higher, even more preferably 95 or higher, and preferably 140 or lower, more preferably 130 or lower, and still more preferably 120 or lower. When the isocyanate index is within the above preferred range, the resulting cured adhesive composition tends to have good light resistance, breaking strength, and breaking elongation.
The isocyanate index is a value obtained by multiplying by 100 the ratio of the number of moles of isocyanate groups in the isocyanate group-terminated urethane prepolymer to the total number of moles of hydroxyl groups in the polyether polycarbonate polyol.

[Chain extender]
The adhesive composition of the present invention may further contain a chain extender from the viewpoint of improving breaking strength by forming hard segments. The chain extender is preferably at least one selected from the group consisting of polyols and polyamines, and preferably has at least two active hydrogens that react with isocyanate groups.

Specific examples of chain extenders include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentane. Linear aliphatic diols such as diol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol; 2-methyl-1 ,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4 -heptanediol, 1,4-dimethylolhexane, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 2 -Butyl-2-ethyl-1,3-propanediol, dimer diol, aliphatic diols with branched chains of neopentyl glycol; 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-dihydroxy Diols having an alicyclic structure such as cyclohexane and 1,4-dihydroxyethylcyclohexane; diols having an aromatic group such as xylylene glycol, 1,4-dihydroxyethylbenzene, and 4,4'-methylenebis(hydroxyethylbenzene); glycerin, Trimethylolpropane, trihydric or higher aliphatic alcohols such as pentaerythritol; N-methylethanolamine, N-ethylethanolamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylene Hydroxyamines such as diamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine; ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane , 4,4'-diphenylmethanediamine, methylenebis(o-chloroaniline), xylylenediamine, metaxylenediamine, diphenyldiamine, tolylenediamine, hydrazine, piperazine, N,N'-diaminopiperazine, which are polyamines without hydroxyl groups. I can list several types. These may be used alone or in combination of two or more.

Among these, ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol are preferred, and 1,4-butanediol is more preferred.

The molecular weight of the chain extender is preferably 60 or more and 1,000 or less, more preferably 60 or more and less than 300.
When the molecular weight of the chain extender is within the above range, the resulting cured adhesive composition tends to have better light resistance, breaking strength, and breaking elongation.

When the adhesive composition of the present invention contains a chain extender, the content thereof is preferably 5 to 30 parts by mass based on 100 parts by mass of the polyether polycarbonate polyol, from the viewpoint that the cured product exhibits appropriate breaking strength. Parts by weight, more preferably 6 to 25 parts by weight, still more preferably 8 to 20 parts by weight.

The adhesive composition of the present invention may further contain a solvent, additives described below, and the like.
As the solvent, the above-mentioned solvents, which can be used as necessary during the production of the isocyanate group-terminated urethane prepolymer, are preferable.
In addition, when a solvent is contained, the amount thereof is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 50 parts by mass or more, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer. , preferably 500 parts by mass or less, more preferably 450 parts by mass or less, still more preferably 400 parts by mass or less.

The total proportion (content) of the isocyanate group-terminated urethane prepolymer and the polyether polycarbonate polyol in the adhesive composition of the present invention is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass. That's all.

[Additives that can be added to the adhesive composition]
The adhesive composition of the present invention may contain hydrolysis inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, fillers, plasticizers, and antistatic agents, as necessary, to the extent that the effects of the present invention are not impaired. , leveling agents, and other optional ingredients.

(hydrolysis inhibitor)
Examples of hydrolysis inhibitors include carbodiimide-based, isocyanate-based, oxazoline-based, and epoxy-based. The hydrolysis inhibitors may be used alone or in combination of two or more. Among these, carbodiimide is preferred from the viewpoint of hydrolysis inhibiting effect.
A carbodiimide-based hydrolysis inhibitor is a compound having one or more carbodiimide groups in one molecule. Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, and naphthylcarbodiimide.
A polycarbodiimide compound can be produced by subjecting a diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidation catalyst.
Examples of the diisocyanate include MDI, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3 '-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, IPDI, 4,4'-dicyclohexylmethane diisocyanate, Tetramethylxylylene diisocyanate is mentioned.
Examples of the carbodiimidation catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, -ethyl-2-phosphorene-1-oxide, 3-phosphorene isomers thereof, and other phosphorene oxides.

The amount of the hydrolysis inhibitor added is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 3 parts by mass or less, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(Antioxidant)
By using an antioxidant, thermal deterioration of the isocyanate group-terminated urethane prepolymer can be prevented.
Examples of the antioxidant include radical scavengers such as phenolic compounds and amine compounds; peroxide decomposers such as sulfur compounds and phosphorus compounds; and the like. One type of antioxidant may be used alone or two or more types may be used in combination.
As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use one or more phenolic compounds which are radical scavengers. One or more phenolic compounds that are radical scavengers and one or more phosphorus compounds that are peroxide decomposers can also be used together.

The amount of the antioxidant added is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(Ultraviolet absorber)
Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid anilide compounds, cyanoacrylate compounds, triazine compounds, and the like. The ultraviolet absorbers may be used alone or in combination of two or more.
The amount of the ultraviolet absorber added is preferably 3 parts by mass or less, more preferably 2.5 parts by mass or less, still more preferably 2 parts by mass or less, per 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(light stabilizer)
Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. One kind of light stabilizer can be used alone or two or more kinds can be used in combination.
The amount of the light stabilizer added is preferably 2 parts by mass or less, more preferably 1.5 parts by mass or less, still more preferably 1 part by mass or less, per 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(filler)
Fillers include, for example, inorganic or organic fillers, such as in particular natural, heavy or precipitated calcium carbonate, optionally coated with fatty acids, in particular stearic acid, barite, talc, Quartz powder, silica sand, dolomite, wollastonite, kaolin, calcined kaolin, mica (potassium aluminum silicate), zeolite, molecular sieves, aluminum oxide, aluminum hydroxide, magnesium hydroxide, finely ground silica from pyrolysis process. containing silica, industrially produced carbon black, graphite, metal powders such as aluminium, copper, iron, silver or steel, PVC powder or hollow spheres as well as flame retardant fillers such as hydroxides or hydrates, in particular Aluminum hydroxides or hydrates, preferably aluminum hydroxide, are mentioned.
The amount of the filler added is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 60 parts by mass or less, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(Plasticizer)
Examples of plasticizers include di-2-ethylhexyl phthalate, dibutyl phthalate, dilauryl phthalate, dioctyl adipate, diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diisodecyl adipate, tributyl phosphate, trioctyl phosphate, propylene glycol adipate polyester. , butylene glycol adipate polyester, epoxidized soybean oil, chlorinated paraffin, and liquid paraffin.
The amount of the plasticizer added is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 25 parts by mass or less, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer.

(Antistatic agent)
Examples of the antistatic agent include inorganic salts, polyhydric alcohol compounds, ionic liquids, surfactants, and the like. The antistatic agents may be used alone or in combination of two or more.
Among these, ionic liquids are preferred. Note that the "ionic liquid" is also referred to as a salt molten at room temperature, and is a salt that has fluidity at 25°C.
The amount of the antistatic agent added is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.05 parts by mass or more, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

(Leveling agent)
Examples of the leveling agent include acrylic leveling agents, fluorine leveling agents, silicone leveling agents, and the like. One type of leveling agent may be used alone, or two or more types may be used in combination. Among these, acrylic leveling agents are preferred.
The amount of the leveling agent added is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, based on 100 parts by mass of the isocyanate group-terminated urethane prepolymer. , and preferably 2 parts by mass or less, more preferably 1.5 parts by mass or less, and even more preferably 1 part by mass or less.

(Other optional ingredients)
Other optional components include, for example, catalysts, resins other than isocyanate group-terminated urethane prepolymers, metal powders, colorants (pigments, etc.), foils, conductive agents, silane coupling agents, lubricants, and corrosion inhibitors. agent, heat stabilizer, polymerization inhibitor, antifoaming agent, etc.

<Method for manufacturing adhesive composition>
The method for producing an adhesive composition of the present invention is a method for producing an adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol, comprising:
In the presence of a catalyst, an initiator having three or more active hydrogen-containing groups in one molecule, a cyclic ether, and carbon dioxide are polymerized to obtain a polyether polycarbonate polyol, and the polyether polycarbonate polyol and isocyanate groups are polymerized. Mix the terminated urethane prepolymer.
The proportion of the structural unit derived from carbon dioxide in one molecule of the polyether polycarbonate polyol is 10 to 30% by mass.

The adhesive composition of the present invention is obtained by mixing a polyether polycarbonate polyol and an isocyanate group-terminated urethane prepolymer. The polyether polycarbonate polyol is obtained by the manufacturing method described in the section [Method for manufacturing polyether polycarbonate polyol].
When mixing the polyether polycarbonate polyol and the isocyanate group-terminated urethane prepolymer, a catalyst component, a solvent, and the above-mentioned additives may be added as necessary. For the mixing, a known stirring mixer such as a plastomill, kneader, Banbury mixer, roll, etc. equipped with a heating device may be used. The mixing is preferably performed under an atmosphere of an inert gas such as nitrogen gas or under a vacuum dehydration atmosphere.
Note that there is no particular restriction on the order in which the above-mentioned components are added.

(Two-component adhesive composition)
The adhesive composition of the present invention may be a two-component adhesive composition comprising a base agent and a curing agent. When the adhesive composition of the present invention is a two-component adhesive composition, for example, it may be a base agent containing the above-mentioned isocyanate group-terminated urethane prepolymer and a curing agent containing the above-mentioned polyether polycarbonate polyol. The main ingredient can be produced, for example, by uniformly stirring and mixing the above-described isocyanate group-terminated urethane prepolymer, a solvent contained as necessary, and one or more of the above-mentioned additives. Further, the curing agent can be produced, for example, by uniformly stirring and mixing one or more of the above-mentioned polyether polycarbonate polyol, a catalyst component to be included as necessary, a solvent, and the above-mentioned additives.
For stirring and mixing, a known stirring mixer such as a plastomill, kneader, Banbury mixer, roll, etc. equipped with a heating device may be used. The stirring and mixing is preferably carried out under an inert gas atmosphere such as nitrogen gas or under a reduced pressure dehydration atmosphere.
Note that there is no particular restriction on the order in which the above-mentioned components are added.
The base agent and curing agent are each housed in separate containers. Various containers can be used, such as tubes and bottles.

When the adhesive composition of the present invention is a two-component adhesive composition, the total proportion (content) of the main agent and curing agent in the adhesive composition is 50% by mass or more and 100% by mass or less. is preferred. The total proportion of the main agent and curing agent is more preferably 55% by mass or more, still more preferably 60% by mass or more, and more preferably less than 100% by mass, still more preferably 99.5% by mass or less, and even more preferably Preferably it is 95% by mass or less.
The content ratio of the main agent and curing agent in the two-component adhesive composition is determined based on the above-mentioned isocyanate index.
The total proportion (content) of the main agent and curing agent in the solid content of the adhesive composition of the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass. % or more, and may be 100% by mass.

(how to use)
When the adhesive composition of the present invention is a two-component adhesive composition, the main ingredient and the curing agent may be mixed together.
The adhesive composition of the present invention can be cured under conditions of, for example, 5 to 90°C and a relative humidity of 5 to 95%. The temperature during mixing is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, and preferably 90°C or lower, more preferably 80°C or lower, even more preferably 60°C or lower. It is. When the temperature is within the above range, side reactions other than the urethane reaction can be easily suppressed.

The adhesive composition of the present invention can be used to bond glass, rubber, metal, resin materials, and the like. Examples of resin materials include polypropylene, polyethylene, ethylene/propylene copolymer, polyolefin such as cycloolefin polymer; polyester of polyethylene terephthalate and polybutylene terephthalate; polymethyl methacrylate; polycarbonate; polystyrene; acrylonitrile/styrene copolymer; polyvinyl chloride. ; polyacetate; acrylonitrile-butadiene-styrene copolymer; and polyamide.
These resin materials may be subjected to surface treatments such as flame treatment, corona treatment, and intro treatment. Further, these resin materials may contain fillers such as talc, calcium carbonate, and alumina, and may be reinforced with carbon fibers and glass fibers.

The adhesive composition of the present invention can be used to join parts of various structures. In addition to being used as an adhesive, the adhesive composition of the present invention can be used, for example, as a coating agent, paint, waterproof material, flooring material, elastomer, artificial leather, or spandex.

<Cured product>
The cured product of the present invention is a cured product obtained by curing the adhesive composition of the present invention.

(physical properties)
The cured product of the adhesive composition of the present invention preferably has a breaking strength of 0.8 MPa or more, more preferably 1.5 MPa or more, and still more preferably 3.0 MPa or more.
The elongation at break of the cured product of the adhesive composition of the present invention is preferably 15.0% or more, more preferably 30.0% or more, and still more preferably 50.0% or more.
The breaking strength and breaking elongation are measured by the method described in the Examples below.

Hereinafter, the present invention will be specifically explained based on Examples, but the present invention is not limited to the Examples below.

(Evaluation method)
<Number of hydroxyl groups in one molecule (number of terminal groups)>
The number of hydroxyl groups in each initiator used in the synthesis of each polyol was directly defined as the number of hydroxyl groups in one molecule of each polyol (number of terminal groups). For example, it is 3 for glycerin, 4 for pentaerythritol, and 6 for sorbitol.

<Hydroxyl value, molecular weight converted to hydroxyl value>
The hydroxyl value (OHV) of each polyol obtained in the synthesis examples described below was calculated by a method using an acetylation reagent in accordance with JIS K 1557 (2007).
The molecular weight of the polyol in terms of hydroxyl value was calculated by applying the hydroxyl value to the formula [56,100/(hydroxyl value)]×(number of functional groups).

<Number average molecular weight (Mn) and molecular weight distribution (Mw/Mn)>
The number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of each polyol obtained in the synthesis examples described below are values obtained by measurement by the method described below.
As a standard sample for molecular weight measurement, several types of monodisperse polystyrene with different degrees of polymerization were measured using a commercially available GPC measurement device (HLC-8320GPC, manufactured by Tosoh Technosystems Co., Ltd.), and the relationship between the molecular weight of polystyrene and retention time was determined. A calibration curve was created based on the relationship, and the measurement sample polyol was diluted to 0.5% by mass with tetrahydrofuran and passed through a filter with a pore size of 0.5 μm. It was measured using Mn and Mw were determined by computer analysis of the GPC spectrum of the measurement sample using the above calibration curve.

<PO-PO-PO chain (AO-AO-AO chain), PO-PO-CO ₂ chain (AO-AO-CO ₂ chain), and CO ₂ -PO-CO ₂ chain (CO ₂ -AO chain) in polyol _-CO2 chain), the proportion of propylene carbonate in the polyol, and the proportion of structural units derived from carbon dioxide>
Each polyol obtained in the synthesis examples described below was dissolved in deuterated chloroform to a concentration of 10% by mass, and ¹ H-NMR was measured using an NMR device with a resolution of 400 MHz (JNM-ECZ400S FT-NMR, product name of JEOL Ltd.). did. From the obtained results, the area S1 of the methyl group-derived 3H peak (δ1.34 ppm) of propylene oxide PO (formula weight 58) as a cyclic ether with both ends adjacent to carbonate, one end adjacent to carbonate and the other end adjacent to PO Area S2 of the 3H peak derived from the methyl group of PO (δ 1.29 ppm), area S3 of the 3H peak derived from the methyl group of PO (δ 1.14 ppm) adjacent to PO on both ends, Based on the area S4 of the methyl group-derived 3H peak (δ1.49 ppm), the proportion of CO ₂ -PO-CO ₂ chains in the polyol (proportion of complete alternating copolymer) and PO-PO-CO ₂ chains are calculated from the following formula. The proportion of (proportion of random copolymer), the proportion of PO-PO-PO chains (proportion of PPG), and the proportion of propylene carbonate were calculated. In the formula below, the formula weight of PO whose both ends are adjacent to carbonate is 102, and the formula weight of PO whose one end is adjacent to carbonate and the other end is 102.
Further, the proportion of structural units derived from carbon dioxide in the polyol (proportion of CO ₂ (formula weight 44)) was calculated from the following formula.
(Ratio of CO ₂ -PO-CO ₂ chains [mass%]) = S1 x 102/(S1 x 102 + S2 x 102 + S3 x 58 + S4 x 102) x 100
(Ratio of PO-PO-CO ₂ chains [mass%]) = S2 x 102/(S1 x 102 + S2 x 102 + S3 x 58 + S4 x 102) x 100
(Ratio of PO-PO-PO chains [mass%]) = S3 x 58/(S1 x 102 + S2 x 102 + S3 x 58 + S4 x 102) x 100
(Ratio of propylene carbonate [mass%]) = S4 x 102/(S1 x 102 + S2 x 102 + S3 x 58 + S4 x 102) x 100
(Ratio of CO ₂ [mass%]) = (S1 + S2) / {(S1 × 102 + S2 × 102 + S3 × 58)} × 44 × 100

<Viscosity at 25°C>
The viscosity of the polyol at 25° C. was measured using an E-type viscometer (VISCOMETER TV-22, manufactured by Toki Sangyo Co., Ltd.).

<Pyrolysis measurement>
5 g of each polyol obtained in the synthesis examples described below was placed in a 15 ml vial, the vial was purged with nitrogen, the vial was sealed tightly, and the vial was stored at a high temperature of 80° C. for 7 days. Thereafter, analysis was performed using a high-speed GPC device (HLC-8320GPC, manufactured by Tosoh Techno System Co., Ltd.) using tetrahydrofuran as a developing solvent, and the area ratio of propylene carbonate after high-temperature storage was calculated.

<Film formability>
The urethane resin obtained in each example was applied onto a commercially available PET film to a thickness of 250 μm, and press molded using a hydraulic molding machine to obtain a urethane resin film. The obtained urethane resin film was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
A: The film surface is flat C: The film surface has unevenness

<Light resistance>
After storing the urethane resin film obtained above in a QUV tester (QUV/SE, manufactured by Q-Lab Corporation) at 50°C for 120 hours, bend the urethane resin film 180° and observe whether it breaks. The degree of deterioration due to UV was evaluated. If there was no damage, it was rated "A", and if it was damaged, it was rated "C".

<Tensile test>
The urethane resin film obtained above was punched out using a dumbbell mold (dumbbell No. 3) to obtain a test piece. Using a tensile tester (product name: Tensilon Universal Tester RTG-1310, manufactured by A&D Co., Ltd.), the breaking strength (unit: MPa) and breaking elongation (unit: :%) was measured. The measurement conditions were a temperature of 23° C., a distance between chucks of 40 mm, and a pulling speed of 50 mm/min.

<Synthesis of polyether polycarbonate polyol>
[Synthesis example 1]
As an initiator, polypropylene polyol (number average molecular weight 870), which is obtained by adding propylene oxide to sorbitol, was used.
A reactor was charged with 46.0 g of the above initiator and 0.04 g of a zinc hexacyanocobaltate complex (hereinafter referred to as "TBA-DMC catalyst") whose ligand is t-butyl alcohol as a catalyst, and the reactor was turned off. A series of operations of heating to 130°C, introducing carbon dioxide, pressurizing (approximately 2.0 MPa), and then reducing the pressure (approximately 0.1 MPa) was repeated three times, followed by degassing at 130°C for 2 hours. After degassing, the carbon dioxide pressure was increased to 6.0 MPa to activate the catalyst. Next, the carbon dioxide pressure during synthesis was maintained at 6.0 MPa, 26.0 g of propylene oxide (PO) as a cyclic ether was added, and after confirming that heat was generated, the liquid temperature was lowered to 110 ° C., and an additional 232 g of PO was added. was added over 14 hours. After reacting at 110°C for 3 hours, the liquid temperature was raised to 130°C and maintained under reduced pressure for 5 hours to remove propylene carbonate as a by-product. Thereafter, the reactant was taken out from the reactor to obtain a polyether polycarbonate polyol (polyol (a1)) having a hydroxyl value of 44.9 mgKOH/g and a CO ₂ proportion of 24.1% by mass. The amount of propylene oxide as the cyclic ether charged was 75.6 parts by mass based on 100 parts by mass of the obtained polyether polycarbonate polyol.

[Synthesis example 2]
Synthesis was carried out in the same manner as in Synthesis Example 1, except that the carbon dioxide pressure when activating the catalyst was changed to 1.5 MPa, and the carbon dioxide pressure during synthesis was changed to 1.5 MPa, and the hydroxyl value was 44.1 mgKOH/ A polyether polycarbonate polyol (polyol (a2)) having a CO ₂ content of 12.3% by mass was obtained. The amount of propylene oxide as the cyclic ether charged was 87.5 parts by mass based on 100 parts by mass of the obtained polyether polycarbonate polyol.

[Synthesis example 3]
As an initiator, polypropylene polyol (number average molecular weight 600), which is obtained by adding propylene oxide to pentaerythritol, was used.
A reactor was charged with 33.0 g of the above initiator and 0.04 g of TBA-DMC catalyst as a catalyst, heated to 130°C, introduced carbon dioxide, pressurized (approximately 2.0 MPa), and then depressurized. (approximately 0.1 MPa) was repeated three times, and then degassed at 130° C. for 2 hours. After degassing, the carbon dioxide pressure was increased to 1.5 MPa to activate the catalyst. Next, the carbon dioxide pressure during synthesis was maintained at 1.5 MPa, 32.0 g of PO as a cyclic ether was added, and after confirming that heat was generated, the liquid temperature was lowered to 110 ° C., and 285 g of PO was added over 17 hours. added. After reacting at 110°C for 3 hours, the liquid temperature was raised to 130°C and maintained under reduced pressure for 5 hours to remove propylene carbonate as a by-product. Thereafter, the reactant was taken out from the reactor to obtain a polyether polycarbonate polyol (polyol (a3)) having a hydroxyl value of 31.5 mgKOH/g and a CO ₂ proportion of 12.5% by mass. The amount of propylene oxide as the cyclic ether charged was 87.2 parts by mass based on 100 parts by mass of the obtained polyether polycarbonate polyol.

[Synthesis example 4]
As an initiator, polypropylene polyol (number average molecular weight 1000), which is obtained by adding propylene oxide to glycerin, was used.
A reactor was charged with 51.0 g of the above initiator and 0.07 g of TBA-DMC catalyst as a catalyst, the reactor was heated to 130°C, carbon dioxide was introduced, and the pressure was increased (approximately 2.0 MPa) and then reduced. (approximately 0.1 MPa) was repeated three times, and then degassed at 130° C. for 2 hours. After degassing, the carbon dioxide pressure was increased to 1.5 MPa to activate the catalyst. Next, the carbon dioxide pressure during synthesis was maintained at 1.5 MPa, 30.0 g of PO as a cyclic ether was added, and after confirming that heat was generated, the liquid temperature was lowered to 110°C, and 270 g of PO was added over 16 hours. added. After reacting at 110°C for 3 hours, the liquid temperature was raised to 130°C and maintained under reduced pressure for 5 hours to remove propylene carbonate as a by-product. Thereafter, the reactant was taken out from the reactor to obtain a polyether polycarbonate polyol (polyol (a4)) having a hydroxyl value of 28.9 mgKOH/g and a CO ₂ ratio of 11.4% by mass. The amount of propylene oxide as the cyclic ether charged was 88.4 parts by mass based on 100 parts by mass of the obtained polyether polycarbonate polyol.

[Synthesis example 5]
A reactor was charged with 25.0 g of sorbitol as an initiator and 1.8 g of cobalt salen complex as a catalyst, the reactor was heated to 50°C, carbon dioxide was introduced, and the pressure was increased (approximately 2.0 MPa) and then reduced. (approximately 0.1 MPa) was repeated three times, and then the carbon dioxide pressure was increased to 2.0 MPa to activate the catalyst. Thereafter, while replacing the inside of the container with carbon dioxide, 143 g of PO as a cyclic ether was added and reacted for 6 hours. After the reaction, 66.7 ml of methanol was added to quench the solvent. After quenching, the liquid temperature was raised to 130°C and maintained under reduced pressure for 5 hours to remove propylene carbonate as a by-product. Thereafter, the reactant was taken out from the reactor to obtain a polyether polycarbonate polyol (polyol (c1)) having a hydroxyl value of 47.5 mgKOH/g and a CO ₂ proportion of 43.1% by mass. The amount of propylene oxide as the cyclic ether charged was 56.7 parts by mass based on 100 parts by mass of the obtained polyether polycarbonate polyol.

<Synthesis of polypropylene polyol>
[Synthesis example 6]
As an initiator, polypropylene polyol (molecular weight 870), which is obtained by adding propylene oxide to sorbitol, was used.
A reactor was charged with 46.0 g of the above initiator and 0.04 g of TBA-DMC catalyst as a catalyst, the reactor was heated to 130°C, nitrogen was introduced, and the pressure was increased (approximately 0.5 MPa), followed by reduced pressure ( After repeating a series of operations three times at a pressure of about 0.1 MPa), the mixture was degassed at 130° C. for 2 hours. After degassing, the nitrogen pressure was increased to 0.1 MPa. Next, 35.0 g of PO as a cyclic ether was added, and after confirming that heat was generated, 319 g of PO was further added over 18 hours. After reacting at 130°C for 2 hours, the liquid temperature was maintained at 130°C for 2 hours under reduced pressure. Thereafter, the reactant was taken out from the reactor to obtain a polypropylene polyol (polyol (c2)) having a hydroxyl value of 44.2 mgKOH/g.

[Synthesis example 7]
As an initiator, polypropylene polyol (molecular weight 1000), which is obtained by adding propylene oxide to glycerin, was used.
A reactor was charged with 47.0 g of the above initiator and 0.04 g of TBA-DMC catalyst as a catalyst, the reactor was heated to 130°C, nitrogen was introduced, and the pressure was increased (approximately 0.5 MPa), followed by reduced pressure ( After repeating a series of operations three times at a pressure of about 0.1 MPa), the mixture was degassed at 130° C. for 2 hours. After degassing, the nitrogen pressure was increased to 0.1 MPa. Next, 35.0 g of PO as a cyclic ether was added, and after confirming that heat was generated, 318 g of PO was further added over 18 hours. After reacting at 130°C for 2 hours, the liquid temperature was maintained at 130°C for 2 hours under reduced pressure. Thereafter, the reactant was taken out from the reactor to obtain a polypropylene polyol (polyol (c3)) having a hydroxyl value of 22.5 mgKOH/g.

In the following examples, Examples 1 to 4 are examples, and Examples 5 to 7 are comparative examples.
[Example 1]
(1) Synthesis of isocyanate group-terminated urethane prepolymer (preparation of main agent)
Into a 2000 ml reaction vessel equipped with a stirrer, 280 g of polyethylene glycol-terminated polypropylene glycol (average number of hydroxyl groups, molecular weight converted to hydroxyl value 4,000) was added, and then 4,4'-diphenylmethane diisocyanate (isocyanate group content 33.0 g) was added. 6% by mass) (hereinafter referred to as MDI) and mixed at room temperature (25°C), the mixture was heated to 80°C and reacted for 3 hours. Then, 560g of oxyethylene group-terminated polyoxyethylene/propylene polyol (average number of hydroxyl groups 3, number average molecular weight 5,100, primary alcohol content 14.5% by mass) was added and mixed, and heated to 80°C for 3 hours. reacted (isocyanate index: 216). Next, after cooling the reaction solution to room temperature (25°C), 100 g of DIDP (isodecyl phthalate) was added as a plasticizer, and carbodiimide-modified MDI (trade name: Millionate MTL, Tosoh Corporation) was added as a hydrolysis inhibitor. 577g of urethane prepolymer P1 (manufactured by Nippon Steel Corporation, isocyanate content: 28.9%) was added and mixed, and the mixture was stirred at room temperature (25°C) to obtain isocyanate group-terminated urethane prepolymer P1 (isocyanate index: 1067).

(2) Preparation of curing agent In a reaction vessel, 48.0 g of the polyether polycarbonate polyol (a1) obtained in Synthesis Example 1, 8.8 g of 1,4-BD as a chain extender, and 1.0 g of metaxylene diamine (MXDA) were placed. 0 g, 10.33 g of zeolite (trade name: SP#600, manufactured by Nitto Funka Kogyo Co., Ltd.) as a filler, and 0.05 g of triethylenediamine as a catalyst were added and stirred with a centrifugal stirrer to obtain a curing agent.

(3) Synthesis of urethane resin 68.2 g of the curing agent obtained above and 85.4 g of isocyanate group-terminated urethane prepolymer P1 and 5.5 g of carbodiimide-modified MDI (trade name: Millionate MTL) as main ingredients are mixed in a stirrer. They were mixed and reacted at room temperature (25°C) to obtain a urethane resin (isocyanate index: 110).
Here, the value obtained by multiplying the number of isocyanate groups in the isocyanate group-terminated urethane prepolymer P1 by 100 with respect to the number of hydroxyl groups possessed by the polyether polycarbonate polyol (a1) was defined as the above-mentioned isocyanate index.

[Examples 2 to 7]
A urethane resin was produced in the same manner as in Example 1, except that the types and amounts of the base resin and curing agent were changed as shown in Table 2.
Table 2 shows the evaluation results of the isocyanate index, film formability, light resistance, breaking strength, and breaking elongation of each adhesive composition.

The urethane resins obtained in Examples 1 to 4 all have good film formability. In addition, all of the cured products obtained good results in terms of light resistance, breaking strength, and breaking elongation, indicating that they are excellent in light resistance, breaking strength, and breaking elongation.

Claims

An adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol,
The polyether polycarbonate polyol has three or more terminal groups in one molecule, and has a structural unit derived from an initiator, a structural unit derived from a cyclic ether, and a structural unit derived from carbon dioxide, and An adhesive composition in which the proportion of the structural unit derived from carbon dioxide in one molecule is 10 to 30% by mass.
The adhesive composition according to claim 1, wherein the polyether polycarbonate polyol has a molecular weight in terms of hydroxyl value of 500 to 20,000.
The polyether polycarbonate polyol has a molecular weight distribution (Mw/Mn) expressed as a ratio of weight average molecular weight (Mw) and number average molecular weight (Mn) of 1.05 to 3.00, according to claim 1. Adhesive composition.
The proportion of structural units in which the carbon dioxide-derived structural units, the cyclic ether-derived structural units, and the carbon dioxide-derived structural units are chained in this order in the polyether polycarbonate polyol is 2% by mass or more. , the adhesive composition according to claim 1.
The structural unit derived from the cyclic ether that the polyether polycarbonate polyol has is at least one structural unit selected from the group consisting of structural units derived from ethylene oxide and structural units derived from propylene oxide. 1. The adhesive composition according to 1.
The adhesive composition according to claim 1, wherein the terminal group of the polyether polycarbonate polyol is a hydroxyl group.
The adhesive composition according to claim 6, wherein the molar ratio of the isocyanate groups in the isocyanate group-terminated urethane prepolymer to the hydroxyl groups in the polyether polycarbonate polyol is 100 times greater than or equal to 80 and less than or equal to 150.
The adhesive composition according to claim 1, wherein the content of the polyether polycarbonate polyol is 10 to 70% by mass based on the total amount of the adhesive composition.
The adhesive composition according to claim 1, further comprising a chain extender.
A cured product of the adhesive composition according to any one of claims 1 to 9.
A method for producing an adhesive composition comprising an isocyanate group-terminated urethane prepolymer and a polyether polycarbonate polyol, the method comprising:
In the presence of a catalyst, an initiator having three or more active hydrogen-containing groups in one molecule, a cyclic ether, and carbon dioxide are polymerized to obtain a polyether polycarbonate polyol, and the polyether polycarbonate polyol and isocyanate groups are polymerized. Mix the terminal urethane prepolymer,
A method for producing an adhesive composition, wherein the proportion of structural units derived from carbon dioxide in one molecule of the polyether polycarbonate polyol is 10 to 30% by mass.
The method for producing an adhesive composition according to claim 11, wherein the catalyst includes at least one selected from the group consisting of a composite metal cyanide complex catalyst and a metal salen complex catalyst.
The isocyanate group-terminated urethane prepolymer is a reaction product obtained by reacting a polyol and a polyisocyanate compound such that a molar ratio of 100 times the isocyanate group in the polyisocyanate compound to the hydroxyl group in the polyol is 110 or more and 600 or less. The method for producing an adhesive composition according to claim 11 or 12.