JPH08165326A - Blocked polyisocyanate resin composition and its production - Google Patents

Abstract

PURPOSE: To obtain a blocked polyisoyahate resin composition useful for a coating material, an adhesive, a textile processing agent or the like, chemically stable, and excellent in weather resistance and particularly low-temperature curability. CONSTITUTION: This composition essentially consists of a polyfunctional blocked polyisocyanate having at least four blocked isocyanate groups at the terminals on the average and having a number-average molecular weight of 600-4000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blocked polyisocyanate resin composition which is useful in industrial fields such as paints, fibers and adhesives and which is excellent in low temperature curability.

[0002]

Polyurethane resins generally have excellent mechanical properties such as abrasion resistance and chemical resistance, and polyisocyanates derived from diisocyanates are widely used as curing agents for polyurethane resins. Has been. However, since polyisocyanate has high activity and has an isocyanate group having reactivity with water, it is unstable to moisture, and has a short pot life when used in combination with a polyol. There were practical restrictions such as.

As a method for improving such restrictions, blocked isocyanates which can be used stably in one liquid by blocking active isocyanate groups with an active hydrogen compound having a thermal dissociation property (hereinafter referred to as a blocking agent) Has been developed. However, blocked isocyanates require high-temperature heating for regeneration of isocyanate groups in practical use, and therefore they are apt to cause color burning of products and further deterioration of quality due to thermal deterioration of products, and various disadvantages such as energy cost required for heating. Had.

Therefore, it has long been desired to develop a blocked isocyanate having excellent low-temperature dissociation properties, and the present inventors have found that blocked isocyanates having excellent low-temperature curability, curing catalysts for imparting low-temperature curability, and specified Various studies have been conducted on the combination with the above polyols and the like. However, a block isocyanate excellent in low temperature dissociation derived from an alkylene diisocyanate such as hexamethylene diisocyanate which is chemically stable and has excellent weather resistance and which is particularly useful as an industrial material in the field of coating has not yet been completed. Not in.

[0005]

Therefore, the problems to be solved by the present invention are useful for paints (for automobiles, powder paints, cans, pre-coated metal), adhesives, fiber processing agents, etc. It is an object of the present invention to provide a resin composition containing a blocked polyisocyanate that is chemically stable, has excellent weather resistance, and particularly excellent in low temperature curability, and a method for producing the resin composition.

[0006]

Means for Solving the Problems The present inventors have focused their attention on the above-mentioned problems, and as a result of earnest research, as a result, a polyfunctional block having a number average molecular weight of 600 to 4000 and having an average of 4 or more blocked isocyanate groups at the end. Block polyisocyanate resin composition containing polyisocyanate as an essential constituent is excellent in low-temperature dissociation property, and in practical use, even if a relatively small amount is used with respect to a functional group contained in the main component polyol, for example, a hydroxyl group. The inventors have found that they cure sufficiently and have completed the present invention.

That is, the present invention has a number average molecular weight of 600, which has an average of 4 or more blocked isocyanate groups at the end.
Up to 4000 polyfunctional blocked polyisocyanates (A)
A block polyisocyanate resin composition containing as an essential component.

Further, the present invention is a block polyisocyanate resin composition characterized in that the block polyisocyanate resin composition contains a curing accelerating catalyst (B) as an essential component. Specifically, the polyfunctional blocked polyisocyanate (A) comprises a reaction product of an isocyanate prepolymer (a), a polyhydroxy compound (b), and a blocking agent (c), which is a blocked polyisocyanate resin composition. It is a thing.

More specifically, the block polyisocyanate resin composition in which the curing-accelerating catalyst (B) is at least one selected from the group consisting of organic tin compounds, organic zinc compounds, and quaternary ammonium compounds.

More specifically, the isocyanate prepolymer (a) is an isocyanurate type polyisocyanate,
A block isocyanate resin composition characterized by being derived from an adduct type polyisocyanate or an alkylene diisocyanate. In particular, the block isocyanate resin composition is characterized in that the isocyanate group of alkylene diisocyanate is bonded to primary carbon.

A polyhydroxy compound (b) is a polyhydroxyalkane, which is a blocked polyisocyanate resin composition. Blocking agent (c)
Is an active hydrogen compound, and is a blocking agent (c).
Is a ketoxime compound, which is a block isocyanate resin composition.

The present invention further comprises (a) an isocyanate prepolymer (a) and a polyhydroxy compound (b),
Comprising a first step of carrying out a urethanization reaction under reaction conditions with excess isocyanate groups, and (b) a second step of blocking unreacted isocyanate groups remaining in the first step with a blocking agent (c). Number average molecular weight 600 to 40 having an average of 4 or more blocked isocyanate groups at the end
No. 00 polyfunctional blocked polyisocyanate (A).

The present invention also comprises (a) a first step of blocking the isocyanate prepolymer (a) with a blocking agent (c) under reaction conditions with excess isocyanate groups,
(B) a second step in which an unreacted residual isocyanate group in the first step is subjected to a urethanization reaction with the polyhydroxy compound (b), and a number average molecular weight having an average of 4 or more blocked isocyanate groups at the end. 600-400
0 is a method for producing a polyfunctional blocked polyisocyanate (A).

More specifically, the present invention relates to a polyfunctional blocked polyisocyanate (A) in which the isocyanate prepolymer (a) is an isocyanurate type polyisocyanate and / or an adduct type polyisocyanate.
Of the polyhydroxy compound (b), wherein the polyhydroxy compound (b) is a polyhydroxyalkane.

The present invention will be described in more detail below. The polyfunctional blocked isocyanate of the present invention has a terminal 4
Polyisocyanates having an isocyanate group blocked with at least one blocking agent, the block being dissociated by heating, and the isocyanate group being regenerated to exhibit reactivity. These polyfunctional blocked isocyanates are composed of a reaction product of an isocyanate prepolymer (a), a polyhydroxy compound (b) and a blocking agent (c).

As the isocyanate monomer which is a raw material of the isocyanate prepolymer (a), any known and commonly used compounds can be used. For example, isophorone diisocyanate, bis (isocyanate) cyclohexane, hydrogenated diphenylmethane diisocyanate, and 1 , 3- or 1,4-diisocyanate, cycloalkylene diisocyanate such as cyclohexane,

Examples thereof include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate, araliphatic diisocyanates such as xylylene diisocyanate and tetramethylxylylene diisocyanate, and lysine diisocyanate.

In the case of the present invention, a blocked polyisocyanate which is chemically stable and has excellent weather resistance and which is derived from an alkylene diisocyanate and has an excellent low-temperature curing property is particularly preferable. Tetramethylene diisocyanate, 1,
A diisocyanate compound having an isocyanate group bonded to primary carbon, such as 6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, is preferred.

When a blocked isocyanate produced by using these primary carbon-bonded diisocyanate compounds is used as a coating in combination with a polyol and cured by heating, the isocyanate group regenerated by heat is contained in the cured coating film. Crosslinks are formed by urethane bonds leading to primary aliphatic carbons.

This is the most thermally and chemically stable urethane bond among the urethane bonds and has excellent durability. That is, the above-mentioned urethane bond is the most thermally and chemically stable and excellent in durability as compared with a urethane bond connected to a secondary or tertiary aliphatic carbon, or a urethane bond connected to an aromatic carbon. Will be things.

Further, the isocyanate prepolymer (A) of the present invention is preferably a tri- or higher functional polyisocyanate derived from the above-mentioned isocyanate monomer, and isocyanurate ring-containing polyisocyanate, for example, represented by the general formula 1. Isocyanurate type polyisocyanate, modified isocyanurate ring-containing polyisocyanate with alcohol or the like, or adduct type polyisocyanate represented by the general formula 2 obtained from an isocyanate monomer and a polyhydroxy compound (C).

(General formula 1)

Embedded image

(In the formula, n represents the number of nuclides of the isocyanate prepolymer, and the statistical average value thereof is 1.0 to 1.
5 and R1 to R3 are the same or different and have 4 to 4 carbon atoms.
20 represents a group selected from an alkylene group, a cycloalkylene group, an aralkylene group and an aryl group. )

(General formula 2)

Embedded image

(In the formula, R4 to R6 are the same or different,
It represents a group obtained by removing an isocyanate group from an aliphatic, alicyclic or aromatic diisocyanate, and R7 represents a group obtained by removing a hydroxyl group from a triol compound. )

The polyhydroxy compound (b) is a polyhydroxy compound having two or more hydroxyl groups in one molecule and having a molecular weight of about 100 to 700, preferably 1
The blocked polyisocyanate resin composition of the present invention is a polyhydroxyalkane having 3 to 4 hydroxyl groups in the molecule, and more preferably a polyhydroxyalkane having 3 to 4 hydroxyl groups in one molecule. It is preferable for maximizing the low-temperature curability and obtaining a cured resin having excellent durability.

If the molecular weight of the polyhydroxy compound is too large, the compatibility of the blocked isocyanate of the present invention with the polyol as the main ingredient is impaired, which is not preferable. Examples of the polyhydroxy compound (b) include glycerin, trimethylolethane, trimethylolpropane, trimethyloloctane, hydrogenated oleyl alcohol trimer, pentaerythritol, diglycerin, and ditrimethylolpropane.

Further, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,10-
Decanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,12-hydroxystearyl alcohol, hydrogenated oleyl alcohol dimer, 1,4-bis (hydroxymethyl) cyclohexane,

Further, dimethylolpropionic acid, a polyester oligomer having two or more hydroxyl groups in one molecule and having a molecular weight of about 100 to 700, an acrylic oligomer, an epoxy oligomer, a fluorine oligomer, a polyether oligomer, a halogenated compound. Alkyl oligomers may be used, or they may be used in combination.

Examples of the polyester oligomer having a molecular weight of about 100 to 700 in the present invention include adipic acid, sebacic acid, azelaic acid, hymic acid anhydride, 1,2,5-hexatricarboxylic acid, and 1,1.
-Cyclohexanedicarboxylic acid, hexahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, methylhexahydrophthalic acid,

4-tert-butylcyclohexanemonocarboxylic acid, hexahydrobenzoic acid, tetrachlorophthalic anhydride, tetrahydrophthalic anhydride, tetrahydrophthalic acid, hexahydrophthalic acid, benzoic acid, p-tertiarybutylbenzoic acid, p- Methylbenzoic acid, trimellitic anhydride, pyromellitic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexatricarboxylic acid, 2,
5,7-naphthalenetricarboxylic acid,

(Anhydrous) maleic acid, (anhydrous) phthalic acid,
An acid (anhydride) alone or in a mixture selected from the group of carboxylic acids such as isophthalic acid and terephthalic acid, and an alkyl polyol, for example, ethylene glycol, propylene glycol, butylene glycol, 1,3-butanediol, Neopentyl glycol, trimethylolpropane, trimethylolbutane, trimethylolpentane,

Polyester polyol obtained by condensation reaction with a polyol selected from the group consisting of trimethylolhexane, trimethylolheptane, trimethyloloctane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, glycerin and diglycerin, alone or in a mixture.
Resin may be mentioned.

Further, for example, lactone monomers such as ε-caprolactone and δ-valerolactone are used as neopentyl glycol, trimethylolpropane, trimethylolbutane, trimethylolpentane, trimethylolhexane, trimethylolheptane, trimethyloloctane and ditrimethylolpropane. , Pentaerythritol,
Polyester commonly called lactone polyol obtained by ring-opening polymerization using polyols such as glycerin and diglycerin,

Furthermore, lauric acid monoglyceride, myristic acid monoglyceride, palmitic acid monoglyceride, stearic acid monoglyceride fatty acid monoglycerides are contained, and the amount of these raw materials used is adjusted according to the desired number of hydroxyl groups and number average molecular weight.

As the polyether oligomer, for example, polyvalent alcohol such as glycerin, propylene glycol, pentaerythritol or the like, or a mixture thereof, is added with an alkylene oxide such as ethylene oxide or propylene oxide, or a mixture thereof. Polyether polyols and the like obtained by the above are included.

As the acrylic oligomer, for example, 2-hydroxyethyl acrylate, 2-acrylic acid acrylate
Acrylic esters having active hydrogen such as hydroxypropyl and acrylate-2-hydroxybutyl, or glycerin, alone or a mixture and acrylic ester selected from the group of acrylic acid monoesters or methacrylic acid monoesters of trimethylolpropane, A single or a mixture selected from the group of methacrylic acid esters as an essential component, in the presence or absence of a single or a mixture selected from the group of unsaturated carboxylic acids, unsaturated amides, other polymerizable monomers, Examples thereof include low molecular weight acrylic polyol resins obtained by polymerization.

Examples of the epoxy oligomer referred to in the present invention include novolac type, β-methyl epichloro type,
Cyclic oxirane type, glycidyl ether type, glycol ether type, epoxy type of aliphatic unsaturated compound, epoxidized fatty acid ester type, polyvalent carboxylic acid ester type, aminoglycidyl type, halogenated type, resorcin type, etc. 1
Examples thereof include low molecular weight epoxy resins having two or more hydroxyl groups in the molecule.

Further, examples of the fluoropolyol referred to in the present invention include copolymers having a low molecular weight such as fluoroolefin, cyclohexyl vinyl ether, hydroxyalkyl vinyl ether, vinyl monocarboxylic acid ester and the like. To be

As the polyhydroxy compound (b), in addition to the above-mentioned polyols, castor oil derivatives such as polycarbonate polyol, polybutadiene polyol, polypentadiene polyol, soybean oil, castor oil, castor oil monoglyceride, hydrogenated castor oil, hydrogenated castor oil derivative or Examples thereof include a hydroxyl group-containing silicone resin, and two or more of these may be used in combination.

The blocking agent (c) used in the present invention is an active hydrogen compound, and examples thereof include a ketoxime derivative and a lactam derivative.
Other examples include derivatives of compounds such as phenol, active methylene, alcohol, mercaptan, acid amide, imide, imidazole, urea, and carbamate. Specific examples thereof include the following.

Ketooxime derivatives: methyl ethyl ketone oxime, butanone oxime, formamide oxime,
Acetamide oxime, acetone oxime, methyl isobutyl ketone oxime, methyl amyl ketone oxime,
Diacetyl monooxime, benzophenone oxime, cyclohexanone oxime, methylhexanone oxime, etc.

Lactam derivative: ε-caprolactam, δ
-Caprolactam, β-butyrolactam, β-propiolactam and the like. Phenol derivative: phenol, cresol, xylenol, ethylphenol, nonylphenol, isopropylphenol, p-tert-butylphenol, thymol, p-nitrophenol, p-naphthol, p-
Chlorophenol, p-tert-octylphenol and the like.

Active methylene derivative: ethyl acetoacetate,
Diethyl malonate, methyl acetoacetate, dimethyl malonate, acetylacetone, etc. Alcohol derivative: methanol, ethanol, propanol, isopropanol, 2-ethylhexanol and the like. Mercaptan derivative: butyl mercaptan, t-dodecyl mercaptan, thiophenol, etc.

Acid amide derivatives: acetanilide, acetanisidide, acetic acid amide, acrylamide, benzamide and the like. Imide derivatives: succinimide, maleic imide and the like. Imidazole derivative: 2-phenylimidazoline, imidazole, pyrazole, triazole and the like.

Urea derivatives: urea, thiourea, ethylene urea, diphenyl urea and the like. Carbamate derivative: phenyl N-phenylcarbamate, 2-oxazolidone and the like.

The curing-accelerating catalyst (B) of the present invention is composed of at least one of an organic tin compound, an organic zinc compound, and a quaternary ammonium compound.
Examples of the above-mentioned organic tin compound include general formulas 3 and 4
The compound represented by

(General formula 3)

Embedded image

(General formula 4)

[Chemical 4]

(In the formula, R8 and R10 have 1 to 12 carbon atoms.
R9 is a hydrogen atom or an alkyl group having 1 to 21 carbon atoms, an alkenyl group, an aralkyl group, a cycloalkyl group, an alkoxyalkyl group or an aryl group, and the —OCOR9 group is any of these R9. It is a carboxylic acid residue having 2 to 22 carbon atoms having a group of. X and Y are OCOR9, OH, halogen such as chlorine, 1 / 2O and 1 / 2S, and may be the same or different from each other. Z is O, S or a divalent carboxylic acid residue, and p represents an integer of 0 or 1. )

Typical examples of the compounds represented by the general formulas 3 and 4 include monobutyltin trioctyl acid salt, monooctyltin triacetate salt, monooctyltin trioctyl acid salt, and monooctyltin trilauric acid salt. , Inluppio, monooctyltin tribenzoate, monolauryltin trioctylate, monophenyltin trioctylate, monobutyltin dioctylate / monohydroxide, quiside,

Monooctyltin diacetate / monohydroxide, monolauryltin bismethoxybenzoate / monohydroxide, monooctyltin monoacetate / dichloride, monophenyltin dibenzoate / monochloride, monophenyltin di Benzoate / oxide (+), dibutyltin dicaproate, dibutyltin dilaurate, dioctyltin diacetate, dioctyltin dioctylate,

Dioctyltin dilaurate, octyltin dibenzoate, dioctyltin bismethoxybenzoate,
Dilauryltin dilaurate, dilauryltin dioctylate, bis (dibutyltin monoacetate) oxide, bis (dioctyltin monoacetate) oxide, bis (dimethyltin monoacetoacetate) sulfide,

Bis (dibutyltin monolaurate) sulfide, bis (dibutyltin monoacetate) adipate, bis (dioctyltin monoacetate) maleate, bis (dibutyltin monoacetoacetate) phthalate, bis Examples thereof include (dilauryl tin monobenzoate) phthalate and (dioctyl tin monoacetate) thiodipropionate.

As the organic zinc compound, compounds represented by the general formula 5 can be mentioned.

(General formula 5)

Embedded image

(In the formula, R11 is the same group as R9 in the general formula 4, M is zinc, and q is an integer of 0 or 1.)

As typical examples of the compound represented by the general formula 5, zinc diacetate, zinc dioctylate, zinc dilaurate, zinc dimyristate, zinc bisacetoacetate, zinc dibenzoate, Examples thereof include bis (zinc monoacetate) oxide, bis (zinc monooctylate) oxide, bis (zinc monolaurate) oxide, zinc diacetylbenzoylmethane, and zinc lauroyl / benzoylmethane.

Typical examples of the quaternary ammonium compound include 2-hydroxyethyl tri-n-butylammonium 2,2-dimethylpropionate and 2
-Hydroxyethyl tri-n-butylammonium
2,2-dimethylbutanoate, 2-hydroxypropyl-tri-n-butylammonium-2,2-dimethylpropionate, 2-hydroxypropyl-tri-n-butylammonium-2,2-dimethylbutanoate,

2-Hydroxypropyl tri-n-butylammonium 2,2-dimethylpentanoate, 2-
Hydroxypropyl tri-n-butylammonium ・ 2
-Ethyl 2-methylpropionate, 2-hydroxypropyl tri-n-butylammonium 2-ethyl 2-
Methyl butanoate, 2-hydroxypropyl tri-n
-Butylammonium 2-ethyl 2-methylpentanoate,

2-Hydroxypropyl tri-n-octylammonium 2,2-dimethylpropionate, 2
-Hydroxypropyl tri-n-octylammonium-2,2-dimethylbutanoate, 2-hydroxypropyl-triamylammonium-2,2-dimethylbutanoate, 2-hydroxypropyl-triamylammonium-2,2- Dimethyl pentanoate and the like can be mentioned.

Next, the manufacturing method of the present invention will be described in detail. The isocyanate prepolymer (a) of the present invention can be easily produced from an isocyanate monomer by a known and commonly used method. Next, the blocked polyisocyanate (A) of the present invention is obtained by reacting the isocyanate prepolymer (a) with the hydroxy compound (b) and blocking the remaining isocyanate groups with the blocking agent (c).
When the isocyanate prepolymer (b) is trifunctional, the charging equivalent ratio with the polyhydroxy compound (b) is usually NCO / OH ratio 3 /
It is 1 to 30/1, preferably 3/1 to 10/1, and more preferably 3/1 to 8/1.

When the equivalent ratio is less than 3, an undesired chain extension reaction occurs between the isocyanate compound and the polyhydroxy compound, resulting in an increase in viscosity and, in some cases, gelation. Upon blocking, the active hydrogen of the blocking agent (c) is added to the isocyanate group,
The NCO / H (active hydrogen) equivalent ratio is 0.9 to 1.2, preferably 0.95 to 1.05, and the remaining isocyanate groups are blocked.

Further, the following method can be mentioned as another manufacturing method. That is, it is a method for producing a blocked polyisocyanate in which a part of the isocyanate groups of the isocyanate prepolymer (a) is blocked with a blocking agent in advance and the remaining isocyanate groups are reacted with the polyhydroxy compound (b).

In this production method, when the isocyanate group is blocked in advance, the isocyanate group is blocked so that an equivalent amount of the isocyanate group corresponding to the hydroxyl group of the polyhydroxy compound (b) remains. A blocked polyisocyanate (A) having a certain number can be obtained.

That is, for example, when a blocked polyisocyanate (A) having an average pentafunctionality is obtained, a trifunctional (ie,
2 mol of the isocyanate prepolymer (a having 3 isocyanate groups) and 2 mol of the bifunctional, that is, 1 mol of the isocyanate prepolymer (a) having 2 isocyanate groups are blocked with 5 mol of a blocking agent in advance. After that, it is obtained by reacting 1 mol of a trifunctional (that is, having three hydroxyl groups) hydroxyalkane compound.

Similarly, in the case of obtaining an average hexafunctional block polyisocyanate (A), 3 moles of the trifunctional isocyanate prepolymer (a) is blocked with 6 moles of a blocking agent in advance, and then the trifunctional hydroxyalkane is used. Obtained by reacting 1 mol of the compound.

Similarly, when a 7-functional blocked polyisocyanate (A) is obtained, 3 mol of the trifunctional isocyanate prepolymer (a) and 1 mol of the bifunctional isocyanate prepolymer (a) are previously added with 7 mol of the blocking agent. After blocking, tetrafunctional hydroxyalkane compound 1
Obtained by reacting moles.

Similarly, to obtain an octafunctional blocked polyisocyanate (A), 4 moles of the trifunctional isocyanate prepolymer (a) is blocked with 8 moles of a blocking agent in advance, and then the tetrafunctional hydroxyalkane compound is obtained. 1
Obtained by reacting moles.

The reaction temperature in the above reaction is from room temperature to 2
The temperature is in the range of 00 ° C, preferably 40 to 150 ° C, more preferably 40 to 120 ° C. When the reaction temperature is low, it takes too much time to complete the reaction, and conversely 2
Reaction conditions exceeding 00 ° C. are not preferred because side reactions occur.

Although the reaction can be carried out without solvent,
You may use any solvent inert to the isocyanate group, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, esters such as propylene glycol monomethyl ether acetate, toluene,
Aromatic compounds such as xylene and ketones such as methyl ethyl ketone are preferably used.

If necessary, a urethane-forming catalyst such as an organic tin compound may be used to accelerate the reaction. The amount of the catalyst is usually 5 to 5000 ppm by weight fraction with respect to the solid content,
Preferably 10 to 500 ppm, more preferably 20 to
It is 200 ppm. When the amount of the catalyst used for the urethanization reaction is 50,000 ppm or more, a side reaction occurs even in the preferable reaction temperature range of 40 to 150 ° C., and the desired composition is difficult to obtain, which is not preferable. Also, 5
When it is less than ppm, the reaction generally takes a long time, which is not preferable.

The number average molecular weight of 600, which has an average of 4 or more blocked isocyanate groups at the terminal obtained in the present invention, is 600
Up to 4000 polyfunctional blocked polyisocyanates (A)
Is theoretically designed to have 5 to 8 blocked isocyanate groups at the terminal, but in the actually obtained polyfunctional blocked polyisocyanate (A), the terminal isocyanate group is further In order to react with the polyol and increase the molecular weight, when the whole is averaged, the polyfunctional blocked polyisocyanate (A) has an average of 4 or more blocked isocyanate groups at the terminals.

That is, the composition containing the polyfunctional blocked polyisocyanate (A) of the present invention contains a polyfunctional blocked polyisocyanate having an average of 4 or more blocked isocyanate groups at the end thereof in an amount of 40% based on the whole blocked polyisocyanate. % Or more. Compared to conventional blocked polyisocyanates, compared to the overall molecular weight,
Since a large number of blocked isocyanate groups are contained per molecule, the obtained coating composition has extremely excellent low temperature curability.

When the blocked polyisocyanate composition of the present invention is baked to obtain a cured resin, the above-mentioned curing-accelerating catalyst (B) is generally used alone or in combination. The amount of the catalyst used is usually 0.1 to 8.0% by weight, preferably 0.3 to 6.0% by weight based on the solid content of the blocked polyisocyanate and the polyol. When the amount of the catalyst is small, the performance as a curing catalyst is not sufficiently exhibited, and when it is excessively large, the storage stability of the blocked polyisocyanate is deteriorated, and the performance of the cured resin may be impaired. Absent.

When the blocked polyisocyanate of the present invention is put to practical use, it is generally used as a resin composition in combination with a main agent, a polyol such as polyester polyol, acrylic polyol, epoxy polyol, fluorine polyol and the like. At that time, another curing agent such as a melamine resin may be used in combination.

When the blocked polyisocyanate of the present invention is used, the proportion of the main agent, that is, the polyol, is usually such that the proportion of active hydrogen in the main agent is equal to the calculated value of the isocyanate group regenerated from the block polyisocyanate. However, the block polyisocyanate of the present invention is polyfunctional and has extremely excellent curability, and exhibits excellent curability even at low temperatures, and even when the hydroxyl group of the base polyol is excessive. Curing cross-linking occurs.

For example, the conventional blocked isocyanates blocked with methyl ethyl ketoxime or the like usually required a curing temperature of 140 ° C. or higher, but the polyfunctional blocked polyisocyanate according to the present invention has a curing temperature of 120.
Sufficient curing is possible even at ° C, and it has excellent low-temperature curability that has not been obtained in the past.

When the blocked polyisocyanate of the present invention is used as a resin composition, if necessary, an organic pigment, an extender pigment, a dispersant, an antifoaming agent, a leveling agent, a touch modifier, a hindered amine type, Various stabilizers such as hindered phenol type and benzotriazole type may be added.

The blocked polyisocyanate resin composition of the present invention is used for coatings (for automobiles, electric wires, powders, cans,
It is extremely useful as a precoat metal, etc.), adhesive, and fiber processing agent.

[0081]

EXAMPLES Next, the present invention will be described more specifically with reference to synthesis examples, applied examples and applied comparative examples. In the following, all parts and% are based on weight unless otherwise specified.

(Synthesis Example 1) Synthesis of Block Polyisocyanate (BI-1) Bernock DN-901S (Dainippon Ink and Chemicals, Inc .: Aliphatic isocyanurate type polyisocyanate, viscosity: W (Gardner), NCO value : 23.0%)
275.0 parts, 12.5 parts of K-COL-II (manufactured by Kashima Chemical Co., Ltd .: diglycerin) and 0.008 part of dibutyltin diacetate were added and the mixture was kept at 100 ° C. for 3 hours.

Further, methyl ethyl ketone (MEK) was added to 17
After 0.4 parts was added to dissolve the resin, 11 parts of MEKO were added.
The desired blocked isocyanate (nonvolatile content = 69.
8%, effective isocyanate content = 8.9%).
As a result of IR measurement, it was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the NCO group.

The theoretical average number of blocked isocyanate groups is 8
GPC in terms of polystyrene obtained, which is a blocked isocyanate compound having a number average molecular weight of 2506
From the analysis results, the number average molecular weight (Mn) 1425, the weight average molecular weight (Mw) 4347, and NCO% 1 with respect to the solid content
2.7%, converted average number of blocked isocyanate groups 4.
3. The blocked polyisocyanate having a molecular weight of 2506 or more was 47.8% from the GPC area ratio.

(Synthesis Example 2) Synthesis of Block Polyisocyanate (BI-2) After dissolving 300.0 parts of Bernock DN-901S, 0.008 parts of dibutyltin diacetate and 184.8 parts of MEK, tricarboxylic acid was dissolved. After 18.4 parts of methylolpropane was added and reacted, 112.7 parts of MEKO was added to react with the remaining isocyanate groups, and the target blocked polyisocyanate (nonvolatile content = 70.1%, effective isocyanate content = 8.4%). As a result of IR measurement, it was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the NCO group.

The theoretical average number of blocked isocyanate groups is 6
And a blocked isocyanate compound having a number average molecular weight of 2300, and from the obtained GPC analysis results, the number average molecular weight (Mn) 1217 and the weight average molecular weight (Mw) 2
767, NCO% to solid content 16.0%, converted average blocked isocyanate group number 4.6. The blocked polyisocyanate having a molecular weight of 2300 or more is G
It was 40.7% from the PC area ratio.

Synthesis Example 3 Synthesis of Block Polyisocyanate (BI-3) After dissolving 225.0 parts of Bernock DN-901S and 0.006 part of dibutyltin diacetate in 135.3 parts of butyl acetate. , 71.5 parts of MEKO was charged to block a part of the isocyanate groups, and 18.4 parts of trimethylolpropane were added to react with the remaining isocyanate groups to obtain the desired blocked polyisocyanate (nonvolatile content = 70 0.2%, effective isocyanate content = 7.7
%) Was obtained. As a result of IR measurement, 22 due to the NCO group
It was confirmed that there was no absorption peak at 50 cm ^-1 .

Theoretical average number of blocked isocyanate groups is 6
And a blocked isocyanate compound having a number average molecular weight of 2300. From the obtained GPC analysis results, the number average molecular weight (Mn) 2278 and the weight average molecular weight (Mw) 9
941, NCO% to solid content 10.9%, converted average blocked isocyanate group number 5.9. The blocked polyisocyanate having a molecular weight of 2300 or more is G
It was 65.8% from the PC area ratio.

Synthesis Example 4 Synthesis of Block Polyisocyanate (BI-4) 210 parts of Bernock DN-901S, 280 parts of DN-955 and 0.011 part of dibutyltin diacetate were combined with 160. After dissolving in 7 parts, 9 parts MEKO
After charging 0.0 parts to block a part of the isocyanate groups, 23.1 parts of trimethylolpropane were added and reacted with the remaining isocyanate groups to obtain the desired blocked polyisocyanate (nonvolatile content = 70.1%, effective). Isocyanate content = 5.7%) was obtained. The result of IR measurement,
It was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the NCO group.

The theoretical average number of blocked isocyanate groups is 5
And a blocked isocyanate compound having a number average molecular weight of 2715. From the obtained GPC analysis results, the number average molecular weight (Mn) 2277 and the weight average molecular weight (Mw) 5
083, NCO% 8.1% based on solid content, converted average blocked isocyanate group number 4.4. Blocked polyisocyanates having a molecular weight of 2715 or more are GP
It was 62.8% from the C area ratio.

Synthesis Example 5 Synthesis of Blocked Polyisocyanate (BI-5) After dissolving 325 parts of Bernock DN-901S and 0.009 part of dibutyltin diacetate in 199.5 parts of MEK, After 103.3 parts of MEKO was charged to block a part of the isocyanate groups, 37.1 parts of DTMP (manufactured by Koei Chemical Industry Co., Ltd .: ditrimethylolpropane) was added to react with the remaining isocyanate groups to block the target. Polyisocyanate (nonvolatile content = 70.0%,
Effective isocyanate content = 7.5%) was obtained. As a result of IR measurement, it was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the NCO group.

The theoretical average number of blocked isocyanate groups is 8
And a blocked isocyanate compound having a number average molecular weight of 3138. From the obtained GPC analysis results, the number average molecular weight (Mn) 1866, the weight average molecular weight (Mw) 1
0224, NCO% to solids 10.7%, converted average blocked isocyanate group number 4.8. Molecular weight 3138
Block polyisocyanate having the above molecular weight,
It was 56.4% from the GPC area ratio.

Synthesis Example 6 Synthesis of Block Polyisocyanate (BI-6) 200 parts of Bernock DN-901S, 170.3 parts of DN-955 and 0.009 parts of dibutyltin diacetate were added to 142 parts of MEK. After dissolving in 7 parts, 7 parts MEKO
After charging 4.2 parts and blocking a part of the isocyanate groups, 30.4 parts of DTMP (manufactured by Koei Chemical Industry Co., Ltd .: ditrimethylolpropane) was added and reacted with the remaining isocyanate groups to obtain the desired blocked polyisocyanate. (Nonvolatile matter = 70.6%, effective isocyanate content = 5.8%). As a result of IR measurement, it was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the NCO group.

The theoretical average blocked isocyanate group number is 7
And a blocked isocyanate compound having a number average molecular weight of 3553, and from the obtained GPC analysis results, the number average molecular weight (Mn) 2733 and the weight average molecular weight (Mw) 6
214, NCO% 8.2% based on solid content, converted average blocked isocyanate group number 5.3. The blocked polyisocyanate having a molecular weight of 3553 or more is GP
It was 58.6% from the C area ratio.

(Synthesis Example 7) Synthesis of polyol compound (PO-1) Epicron 1050 (manufactured by Dainippon Ink and Chemicals, Inc .: bisphenol A type polyol, epoxy equivalent: 4)
87) 1133.3 parts was dissolved in 519.1 parts xylene and the temperature was raised to 100 ° C., and then diethanolamine was added to 24 parts.
Divide into 4.5 parts. After holding at 100 to 120 ° C. for 3 hours, 115 parts of isopropanol was charged, and nonvolatile content = 69.8%, viscosity = X (gardner), hydroxyl value = 239 amine-modified epoxy polyol (PO-1).
I got

Comparative Synthesis Example 1 Synthesis of Block Polyisocyanate (BC-1) 300.0 parts of Bernock DN-901S and 0.009 parts of dibutyltin diacetate were dissolved in 190.5 parts of butyl acetate. After that, 144.5 parts of MEKO was charged to block the isocyanate groups to obtain the desired blocked polyisocyanate (nonvolatile content = 70.0%, effective isocyanate content = 15.5%). IR measurement results, NCO
It was confirmed that there was no absorption peak at 2250 cm ⁻¹ due to the group. (This mainly contains a blocked isocyanate compound having a trifunctional blocked isocyanate group.)

Comparative Synthesis Example 2 Synthesis of Block Polyisocyanate (BC-2) VESTANAT-T1890 / 100 (Daicel Hu
Rus Co., Ltd .: IPDI-based isocyanurate type poly
Socyanate, NCO value: 17.0%) 300.0 parts
0.008 part of dibutyltin diacetate was added to butyl acetate 17
After dissolving in 3.9 parts, 105.8 parts of MEKO were prepared.
Block the isocyanate groups to block the target
Polyisocyanate (nonvolatile content = 69.9%, effective iso
Cyanate content = 8.8%) was obtained. Result of IR measurement
2250 cm due to NCO group ^-1Absorption peak of
I confirmed that there is no. (This is a trifunctional blocky
Blocked isocyanate compound having a cyanate group
Mainly includes. )

(Coating formulation) The block isocyanate obtained in the above synthesis example and the polyol compound were blended in the formulation shown in Table 1 (isocyanate group / hydroxyl group = 1/1 molar ratio), and butyl acetate was added. In addition, the nonvolatile content was adjusted to 50.0%. As the polyol compound, in addition to PO-1, Acridic A-801 (manufactured by Dainippon Ink and Chemicals, Inc .: acrylic polyol, non-volatile content: 50%, viscosity: R (Gardner), hydroxyl value: 49.9) was also used. . All the blended liquids were uniform and transparent.

(Application Examples and Application Comparative Examples) After immersing the wire mesh in the mixed solution and drying it, 120, 130, 150
After baking and curing at 10 ° C for 10 minutes and 20 minutes, 2
The gel fraction measured by extracting the uncured resin in acetone for 4 hours is shown in the table.

In the table, A801 is Acridic A-801 and BTA is dibutyltin diacetate (10
% Butyl acetate solution), ZnO is zinc dioctylate (1
0% butyl acetate solution), Q-A represents 2-hydroxypropyl trimethyl ammonium-tert-butyl benzoate (10% butyl acetate solution).

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

[Table 3]

[0104]

[Table 4]

[0105]

INDUSTRIAL APPLICABILITY The present invention is useful for paints (for automobiles, powder coatings, cans, pre-coated metals), adhesives, textile finishing agents, etc., chemically stable, weather resistant, and particularly at low temperatures. It is possible to provide a resin composition containing a blocked polyisocyanate having excellent curability, and a method for producing the resin composition.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area C08K 5/56 C08L 75/04 NGD

Claims (15)

[Claims] 1. A block polyisocyanate resin composition containing, as an essential constituent, a polyfunctional block polyisocyanate (A) having an average number of blocked isocyanate groups of 4 or more at the end and having a number average molecular weight of 600 to 4000. 2. The blocked polyisocyanate resin composition according to claim 1, further comprising a curing accelerating catalyst (B) as an essential component. 3. A polyfunctional blocked polyisocyanate (A) comprising a reaction product of an isocyanate prepolymer (a), a polyhydroxy compound (b) and a blocking agent (c). Or the blocked polyisocyanate resin composition described in 2. 4. The curing-accelerating catalyst (B) is an organic tin compound,
The blocked polyisocyanate resin composition according to claim 2 or 3, which is one or more selected from the group consisting of an organozinc compound and a quaternary ammonium compound. 5. The isocyanate prepolymer (a) comprises:
The blocked polyisocyanate resin composition according to claim 3 or 4, which is an isocyanurate type polyisocyanate. 6. The isocyanate prepolymer (a) is
It is an adduct type polyisocyanate, The block polyisocyanate resin composition of Claim 3 or 4 characterized by the above-mentioned. 7. The isocyanate prepolymer (a) comprises:
The block isocyanate resin composition according to claim 3, which is derived from alkylene diisocyanate. 8. The blocked isocyanate resin composition according to claim 7, wherein the isocyanate group of the alkylene diisocyanate is bonded to primary carbon. 9. The blocked polyisocyanate resin composition according to any one of claims 3 to 8, wherein the polyhydroxy compound (b) is a polyhydroxyalkane. 10. The blocked isocyanate resin composition according to any one of claims 3 to 8, wherein the blocking agent (c) is an active hydrogen compound. 11. The blocked isocyanate resin composition according to any one of claims 3 to 8, wherein the blocking agent (c) is a ketoxime compound. 12. A first step in which (i) an isocyanate prepolymer (a) and a polyhydroxy compound (b) are subjected to a urethanization reaction under reaction conditions with an excess of isocyanate groups, and (b) a first step A second step of blocking the unreacted residual isocyanate groups with a blocking agent (c), and a polyfunctional blocked polyisocyanate having an average number of blocked isocyanate groups of 4 or more and a number average molecular weight of 600 to 4000. The manufacturing method of (A). 13. (a) The isocyanate prepolymer (a) remains unreacted in the first step in which it is blocked with a blocking agent (c) under reaction conditions with excess isocyanate groups, and (b) in the first step. A second step of urethanizing the isocyanate group with the polyhydroxy compound (b),
A method for producing a polyfunctional blocked polyisocyanate (A) having a number average molecular weight of 600 to 4000, which has an average of 4 or more blocked isocyanate groups at the terminal and comprises 14. Isocyanate prepolymer (a)
Is an isocyanurate type polyisocyanate and / or an adduct type polyisocyanate, The manufacturing method of polyfunctional block polyisocyanate (A) of Claim 12 or 13 characterized by the above-mentioned. 15. The polyhydroxy compound (b) is a polyhydroxyalkane.
15. The method for producing a polyfunctional blocked polyisocyanate (A) according to any one of 1 to 14.