JP6243236B2 - Polyolefin resin composition for hot melt adhesive and hot melt adhesive film - Google Patents

Description

  The present invention relates to a polyolefin resin composition for hot melt adhesives. More specifically, the present invention relates to a polyolefin resin composition for a hot melt adhesive having low temperature adhesiveness and excellent heat resistance. The present invention also relates to a hot melt adhesive film.

Thermoplastic resins such as thermoplastic elastomers, olefin polymers, vinyl polymers, and engineering plastics are excellent in physical properties, moldability, surface properties, etc., so that they can be used in bulk, sheet, film, etc. It is used in many fields such as automobiles, home appliances, electronics, architecture, and sundries. In order to make these molded products into products having a desired shape, or to improve performance and diversify functions, a plurality of molded products are bonded and combined. In particular, it is widely used to laminate a surface material, weather resistance, and decorative sheet with excellent surface properties, weather resistance, and decorativeness on the outer layer of a resin molded product with rich mechanical properties. Is widely used in automobile interiors, house interiors, and housings for home appliances. However, such a laminated body generally has poor adhesion between the layers, and there are many examples in which an adhesive layer is provided and laminated. As adhesives, solvent-type adhesives and hot-melt type adhesives are used, but solvent-type adhesives tend to have uneven coating and have the disadvantages of adversely affecting the environment and hygiene due to the use of organic solvents. Have. Therefore, there is a demand for a hot melt adhesive that is simple and excellent in adhesive strength.
Such hot-melt adhesives include one or more base polymers selected from the group consisting of ethylene copolymers, styrene block copolymers, and olefin (co) polymers, tackifying resins, crystallinity, and the like. A material containing a polar group-containing compound (Patent Document 1), an amorphous poly α-olefin, a tackifier resin and a polypropylene-based wax (Patent Document 2), a styrene-ethylenepropylene-styrene block copolymer rubber, or A styrene-butadiene-styrene block copolymer rubber added with a liquid plasticizer such as a tackifier resin component and process oil (Patent Documents 3 and 4), and a mixture of a modified polyolefin and a tackifier ( Patent Document 5), formed by blending a styrene block copolymer and an acid-modified wax (Patent Document 6), an acid-modified polypropylene and an acid-modified styrene block copolymer (Patent Document 7), a styrene block copolymer, a tackifier, and an ethylene polymer. (Patent Documents 8, 9, and 10) have been proposed.
However, when such hot melt adhesives are applied to automobile interior materials that require practical heat resistance of about 80 ° C., problems such as skin lifting and peeling in a high temperature atmosphere may occur. There is. By applying the pressure at a relatively high heating temperature during bonding, it may be possible to improve the adhesion to the resin substrate, but the use of the laminate requires automotive design, house interior, In the case of a home appliance housing or the like, there arises a problem that the molded member is damaged and the design is impaired. For these reasons, there is a need for a hot-melt adhesive that can achieve both low-temperature adhesiveness that does not impair the design and practical heat resistance.

Japanese Patent Laid-Open No. 10-168417 JP 2004-284575 A Japanese Patent Laid-Open No. 3-160083 JP-A-8-60121 JP-A-6-293845 Japanese Patent Laid-Open No. 2007-169531 JP 2008-163121 A Japanese Patent Laid-Open No. 11-131037 JP-A-10-279774 Japanese Patent Laid-Open No. 10-265751

  The object of the present invention is to produce a laminate for automobile interiors, house interiors, and home appliance housings, regardless of whether the substrate is a polar or nonpolar material, even when bonded at a low temperature in consideration of design. Polyolefin resins for hot melt adhesives that can produce laminates that have sufficient adhesiveness and satisfy the required heat resistance for each application, and that have excellent heat resistance especially at high temperatures of about 80 ° C It is to provide a composition and a hot melt adhesive film comprising the same

  As a result of intensive studies, the present inventors have found that a resin composition comprising an ethylene-α-olefin copolymer having a melting point in a specific range solves the above-mentioned problem of achieving both low-temperature adhesiveness and heat resistance, The present invention has been completed as follows.

That is, this invention consists of the following structures.
1) A polyolefin resin composition for a hot melt adhesive containing the following (A) and (B). 5 to 95 parts by weight of an ethylene-α olefin copolymer (A) having a melting point of 100 ° C. or more and less than 130 ° C., 5 to 95 parts by weight of an ethylene-α olefin copolymer (B) having a melting point of 130 to 160 ° C. Department. (Here, (A) and (B) are combined to make 100 parts by weight.)
2) The polyolefin for hot melt adhesive according to 1), further comprising 1 to 60 parts by weight of a styrene-based thermoplastic elastomer (C) with respect to 100 parts by weight of the total of (A) and (B) -Based resin composition.
3) The hot melt adhesive according to 1) or 2), further comprising 1 to 60 parts by weight of a tackifier (D) with respect to 100 parts by weight of the total of (A) and (B) Polyolefin resin composition.
4) The storage elastic modulus G ′ (80) measured in the shear mode at a frequency of 10 Hz at 80 ° C. is 0.8 MPa or more, and the storage elastic modulus G ′ (110) measured in the shear mode at a frequency of 10 Hz at 110 ° C. is 0.00. The polyolefin resin composition for hot melt adhesives according to any one of 1) to 3), which is less than 8 MPa.
5) The ethylene-α-olefin copolymer (A) has a tensile modulus of 300 MPa to 700 MPa, and the ethylene-α-olefin copolymer (B) has a tensile modulus of 10 MPa to 200 MPa. The polyolefin resin composition for hot melt adhesives according to any one of 1) to 4).
6) The (A) and / or (B) is a modified ethylene-α olefin copolymer graft-modified with (a) an unsaturated carboxylic acid or derivative thereof and (b) an aromatic vinyl monomer. The polyolefin resin composition for hot melt adhesives according to any one of 1) to 5).
7) The polyolefin resin composition for hot melt adhesives according to any one of 1) to 6), wherein (A) and / or (B) is an ethylene-propylene copolymer.
8) The polyolefin resin composition for hot melt adhesive according to any one of 1) to 7), wherein the ethylene content in (A) and / or (B) is 3 to 20% by weight object.
9) The polyolefin resin composition for hot melt adhesives according to any one of 1) to 8), wherein the styrene thermoplastic elastomer has a styrene content of 20% by weight or less.
10) The styrenic thermoplastic elastomer is at least one selected from a hydrogenated styrene-isoprene block copolymer, a hydrogenated styrene-butadiene block copolymer, and a hydrogenated styrene-butadiene random copolymer. 9) The polyolefin resin composition for hot melt adhesives according to any one of 9).
11) The hot melt according to any one of 1) to 10), wherein the tackifier (D) is a terpene resin, an aromatic modified terpene resin, or an alicyclic petroleum resin. Polyolefin resin composition for adhesives.
12) A hot-melt adhesive film comprising the polyolefin resin composition for hot-melt adhesives according to any one of 1) to 11) and having a thickness of 20 to 200 μm.

  The adhesive resin composition of the present invention can ensure excellent adhesion to any nonpolar resin such as polyolefin resin, polar resin such as acrylic resin and polycarbonate resin, which has been difficult in the past. it can. In particular, it can be used for low-temperature and low-pressure bonding, so it can be used for stacking complex three-dimensional shaped products and skin materials using vacuum forming, vacuum / pressure forming, pressure forming, hot stamping, etc. It can be suitably used for decoration of molded products for automobile interiors, house interiors, and home appliance casings.

Details of the present invention will be described below.
(Ethylene-α-olefin copolymer (A), (B))
The melting point of the ethylene-α olefin copolymer (A) of the present invention is 100 ° C. or more and less than 130 ° C., and the ethylene-α olefin copolymer (B) has a melting point of 130 ° C. or more and 160 ° C. or less. Here, the melting point is the melting obtained when the temperature is raised again at 10 ° C./min after passing through the temperature lowering process after raising the temperature at 10 ° C./min in a nitrogen atmosphere with a differential scanning calorimeter. The temperature defined as the peak top of the observed peak from the endothermic curve is defined as the melting point.

  For example, in automotive interior applications where a decorative sheet is laminated on the surface, it is generally required to maintain excellent adhesion even at a high temperature of 80 ° C. or higher. In addition, in the product for the application, the skin material is bonded and laminated to the base material molded product by, for example, vacuum molding or vacuum / pressure forming, and in this case, the adhesive layer is 100 ° C. to 130 ° C. in order not to damage the skin material. Often molded in the temperature range of ° C. Under such circumstances, the adhesiveness and heat resistance can both be achieved by blending the ethylene-α olefin copolymers (A) and (B) having the above melting points. The melting point of the ethylene-α-olefin copolymer (A) is preferably 105 ° C. or higher and 125 ° C. or lower, more preferably 110 ° C. or higher and 125 ° C. or lower. The melting point of the ethylene-α-olefin copolymer (B) is preferably 130 ° C. or higher and 155 ° C. or lower, and more preferably 135 ° C. or higher and 150 ° C. or lower.

The tensile elastic modulus of the ethylene-α-olefin copolymer (A) is preferably from 300 MPa to 700 MPa, and more preferably from 350 MPa to 600 MPa. The tensile elastic modulus of the ethylene-α-olefin copolymer (B) is preferably 10 MPa or more and 200 MPa or less, and more preferably 10 MPa or more and 100 MPa or less. When the tensile modulus is in the above range, it becomes easy to achieve both adhesiveness and heat resistance. Here, the tensile modulus is when a strain is 0.0005 when a tensile test is performed at 1 mm per minute with an autograph using a 2 (1/3) dumbbell described in JIS K7113 as a test piece. And the value obtained from the stress when the strain is 0.0025.
In general, a hot melt adhesive is softened at a temperature equal to or higher than its melting point, then cooled and solidified after being cooled to a temperature equal to or lower than the melting point. Therefore, when the bonding temperature is close to the required heat resistance temperature, the design is difficult. However, by using a modified ethylene-α-olefin copolymer that satisfies the above requirements, it is possible to achieve both low-temperature adhesiveness and heat resistance of the adhesive layer in the resulting laminate.
Such an ethylene-α olefin copolymer (A), (B) is not particularly limited as long as it satisfies the above characteristics, but the density of the ethylene-α olefin copolymer (A) is 0.88 g / cm 3. As a random copolymer of ethylene and α-olefin having 0.90 g / cm 3 and an ethylene-α olefin copolymer (B), ethylene having a density of 0.86 g / cm 3 to 0.88 g / cm 3 and α- Random copolymers with olefins are preferably used. Here, the density is measured in accordance with JIS K7112.
The α-olefin forming the ethylene-α-olefin random copolymer as described above is usually an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene. , 1-octene, 1-decene, 1-tetradecene, and 1-octadecene are preferable, and propylene is preferable from the viewpoint of heat generation and a point that radicals are easily generated on the polyolefin during graft modification. As the content ratio of ethylene and propylene in the ethylene-propylene copolymer, in the case of the ethylene-α-olefin copolymer (A), the propylene content is 90 to 97% by weight, the ethylene content is 3 to 10% by weight, In the case of the α-olefin copolymer (B), it is preferable that the propylene content is 80 to 90% by weight and the ethylene content is 10 to 20% by weight because both the adhesiveness and the heat resistance tend to be compatible. Furthermore, if the ethylene content is more than the above range, when the modification described later is carried out, the ethylene portion is preceded by a crosslinking reaction, not only the low-temperature adhesiveness is lowered, but also it cannot be obtained as an adhesive film having a good appearance. There is sex. These ethylene-α olefin copolymers may be copolymerized with other dienes, vinyl esters and the like as the third component as long as the above-described thermal characteristics are not impaired. These may be in the form of particles or pellets, and the size and shape are not particularly limited.

One or both of the ethylene-α olefin copolymers (A) and (B) are modified with (a) an unsaturated carboxylic acid and / or a derivative thereof, and (b) an aromatic vinyl monomer. Or a mixture of both may be modified at the same time.
The modified ethylene-α-olefin copolymer can be produced by a general radical grafting method such as a melt kneading method, a solution method, or a suspension method. Of these, the melt-kneading method is preferred because it is economical, simple and highly productive.

  As the radical polymerization initiator, an organic peroxide is generally used. For example, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, Peroxyketals such as 1,2-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; Dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-di (t-butylperoxyisopropyl) benzene, t-butylcumyl peroxide, di-t -Dialkyl peroxides such as butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; benzoyl peroxide Diacyl peroxides such as oxides; t-butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t -Butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butyl peroxyacetate, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, etc. Peroxyesters are preferred. You may use these in combination of 2 or more type.

  The addition amount of the radical polymerization initiator is preferably in the range of 0.01 to 10 parts by weight, preferably in the range of 0.01 to 5 parts by weight, with respect to 100 parts by weight of the ethylene-α-olefin copolymer. More preferably, it is in the range of 0.01 to 2 parts by weight. If the amount is less than 0.01 parts by weight, the modification does not proceed sufficiently. If the amount exceeds 10 parts by weight, the adhesiveness may be lowered due to a decrease in fluidity due to a crosslinking reaction or an increase in gel content.

  (A) Although it does not restrict | limit especially as unsaturated carboxylic acid and / or its derivative (s), For example, it is an anhydride, an amide, an imide, ester etc., and 1 type or 2 types or more are used suitably. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, endo-bicyclo [2.2.1] -5-heptene-2,3-dicarboxylic acid (endic acid), fumaric acid, tetrahydrophthalic acid, Itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid and the like. Specific examples of unsaturated carboxylic acid derivatives include maleenyl chloride, maleimide, maleic anhydride, endic acid anhydride, methyl acrylate, acrylic acid. And acid amide, methyl methacrylate, glycidyl methacrylate, methacrylic acid amide, citraconic anhydride, itaconic anhydride, nadic anhydride, monomethyl maleate, dimethyl maleate, monomethyl fumarate, dimethyl fumarate and the like. Among these unsaturated carboxylic acids or derivatives thereof, preferably acrylic acid, methacrylic acid, maleic anhydride, glycidyl methacrylate, and more preferably maleic anhydride, glycidyl methacrylate, from a low cost point, modified Glycidyl methacrylate is particularly preferred because it can be easily removed in the subsequent drying step.

  (A) It is preferable that the addition amount of unsaturated carboxylic acid and / or its derivative is 0.1-10 weight part with respect to 100 weight part of ethylene-alpha olefin copolymers, 0.1-8 weight part Is more preferably 0.1 to 6 parts by weight, still more preferably 0.1 to 5 parts by weight. . When the addition amount is less than 0.1 parts by weight, the adhesiveness tends not to be sufficiently improved, and when the addition amount exceeds 10 parts by weight, a tendency to increase the by-product of free polymer that does not contribute to grafting is preferable. There is a tendency that it cannot be obtained as a sheet-like or film-like adhesive composition having a shape or appearance.

  In order to improve the graft ratio of the unsaturated carboxylic acid and / or derivative thereof, it is preferable to add (b) an aromatic vinyl monomer. In addition, the coexistence of the aromatic vinyl monomer can suppress the deterioration of the mechanical properties due to the main chain cleavage of the polyolefin, and the heat resistance of the adhesive composition can be maintained.

  (B) Although it does not restrict | limit especially as an aromatic vinyl monomer, Preferably it is C4-C20, More preferably, it is a C6-C15 aromatic vinyl monomer. For example, styrene; methyl styrene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, β-methyl styrene, dimethyl styrene, trimethyl styrene; o-chloro styrene, m-chloro Chlorostyrene such as styrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, trichlorostyrene; o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene, tribromostyrene, etc. Bromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene, trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitrostyrene, dinitrostyrene, Nitrostyrene such as renitrostyrene; vinylphenols such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene, trihydroxystyrene; o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, etc. 1 type, or 2 or more types, such as divinylbenzene; diisopropenylbenzene, such as o-diisopropenylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene; Of these, methylstyrene such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene monomer or divinylbenzene isomer mixture is preferable in that it is inexpensive.

  The amount of the (b) aromatic vinyl monomer added is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin copolymer, and 0.1 to 8 parts by weight. More preferably, it is more preferably 0.1 to 6 parts by weight, and particularly preferably 0.1 to 5 parts by weight. When the addition amount is less than 0.1 parts by weight, the graft ratio of the unsaturated carboxylic acid and / or its derivative to the ethylene-α-olefin copolymer tends to be inferior. On the other hand, when the addition amount exceeds 10 parts by weight, the graft efficiency of the unsaturated carboxylic acid and / or derivative thereof reaches a saturation region, and an excessive crosslinking reaction proceeds, whereby the adhesiveness may be lowered.

  The composition ratio of the ethylene-α olefin copolymers (A) and (B) is preferably 5 to 95 parts by weight of (A) and 5 to 95 parts by weight of (B), more preferably (A). 5 to 50 parts by weight, (B) is 50 to 95 parts by weight, more preferably (A) 5 to 30 parts by weight, and (B) 70 to 95 parts by weight, particularly preferably (A) 5 -20 parts by weight, (B) is 80-95 parts by weight. When (A) is less than 5 parts by weight, the heat resistance tends to be inferior, which is not preferable. Moreover, when (A) is more than 95 weight part, there exists a tendency for the wettability to a base material at the time of adhesion | attachment, and it is unpreferable.

  Regarding the order and method of addition at the time of melt kneading, an unsaturated carboxylic acid and / or a derivative thereof, or an aromatic vinyl monomer is added to the mixture obtained by melting and kneading an ethylene-α olefin copolymer and a radical polymerization initiator. The order of addition is good, and the formation of low molecular weight substances that do not contribute to grafting can be suppressed by carrying out in this order of addition. In addition, the order and method of mixing and melt-kneading the materials added as necessary are not particularly limited.

  The heating temperature at the time of melt kneading is preferably 150 to 240 ° C. from the viewpoint that the ethylene-α-olefin copolymer is sufficiently melted and excessive thermal decomposition or crosslinking reaction does not occur. The time for melt kneading (the time after mixing the radical polymerization initiator) is usually 30 seconds to 60 minutes.

Moreover, as said melt-kneading apparatus, a single screw or a multi-screw extruder, a Banbury mixer, a plast mill, a heated roll kneader, etc. can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder equipped with a pressure reducing device is preferable. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.
The content of the unsaturated carboxylic acid and / or derivative thereof in the modified ethylene-α olefin copolymer is preferably 0.01 to 5% by weight with respect to 100 parts by weight of the base resin. Here, the content is the amount of unsaturated carboxylic acid and / or derivative thereof introduced by graft copolymerization with respect to the main chain of the base resin. If the amount is less than 0.01% by weight, the adhesion may be insufficient depending on the type of adherend. If the amount is more than 5% by weight, the graft chain reacts during melt-kneading to cause partial cross-linking and formability. At the same time, the appearance of the product is deteriorated due to fish eyes, butts and the like, and the adhesiveness is also lowered.

(Styrenic thermoplastic elastomer (C))
The styrenic thermoplastic elastomer (C) of the present invention refers to a thermoplastic elastomer containing styrene, a homologue thereof or an analogue thereof. What is known as a styrenic thermoplastic elastomer can be used without particular limitation. A block copolymer containing a block of styrene, a homologue thereof or an analogue thereof as at least one terminal block and an elastomeric block of a conjugated diene or a hydrogenated product thereof as an intermediate block, or an aromatic vinyl compound Mention may be made of random copolymers with conjugated diene compounds.
Preferred examples of the styrenic thermoplastic elastomer (C) of the present invention include styrene-butadiene diblock copolymer, styrene-butadiene-styrene triblock copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene triblock copolymer, hydrogen Added styrene-butadiene diblock copolymer, hydrogenated styrene-butadiene-styrene triblock copolymer, hydrogenated styrene-isoprene block copolymer, hydrogenated styrene-isoprene-styrene triblock copolymer, hydrogenated styrene-butadiene random copolymer, styrene-isobutylene Examples thereof include diblock copolymers and styrene-isobutylene-styrene triblock copolymers. Furthermore, in addition to styrene, the styrene block may contain a copolymer of styrene and an aromatic vinyl compound such as α-methylstyrene. The styrene content is preferably 1 to 20% by weight, more preferably 5 to 20% by weight, and particularly preferably 10 to 15% by weight. If it exceeds 20% by weight, the adhesive strength is lowered, which is not preferable. Moreover, when lower than 1 weight%, it is unpreferable from a heat resistant viewpoint.

Among these styrenic thermoplastic elastomers, some or all of the unsaturated double bonds in the polymer block mainly composed of the conjugated diene are hydrogenated from the viewpoint of good heat resistance and weather resistance. Hydrogenated styrene-isoprene-styrene triblock copolymer (SEPS), hydrogenated styrene-butadiene-styrene triblock copolymer (SEBS), hydrogenated styrene-butadiene random copolymer (HSBR), styrene-isobutylene-styrene triblock A block copolymer (SIBS) is mentioned. More preferably, from the viewpoint of heat resistance and weather resistance, hydrogenated styrene-isoprene-styrene triblock copolymer (SEPS), hydrogenated styrene-butadiene-styrene triblock copolymer (SEBS), hydrogenated styrene-butadiene random copolymer (HSBR) ) Is preferred.
The above-mentioned styrenic thermoplastic elastomers are commercially available asaprene, tufprene, asaflex, tuftec [Asahi Kasei Kogyo Co., Ltd.]; Dynalon, JSR-TR [manufactured by JSR Corp.]; Quintac [manufactured by ZEON Corporation]; Hibler, Septon [manufactured by Kuraray Co., Ltd.]; Sibustar [manufactured by Kaneka Corporation] can be exemplified. These commercially available products can be used alone or in combination.

  The amount of the styrenic thermoplastic elastomer (C) is preferably 1 to 60 parts by weight. More preferably, it is 5-40 weight part, More preferably, it is 10-30 weight part. When the amount is less than 1 part by weight, the adhesive strength may be low, which is not preferable. Moreover, when it exceeds 60 weight part, the elasticity in the high temperature area | region of a composition falls and it is unpreferable from a heat resistant viewpoint.

(Tackifier (D))
There are various tackifiers (D) of the present invention. For example, petroleum resins (aliphatic, alicyclic, aromatic, etc.), terpene resins (α-pinene, β-pinene, Polymers such as limonene), aromatic hydrocarbon-modified terpene resins, rosin resins (gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, etc.), terpene phenol Resins etc. are mentioned, These can be used individually or in combination of 2 or more types. Among these, when a modified ethylene-α olefin is used, an alicyclic petroleum resin, terpene resin (α-pinene, β-pinene, limonene, etc.) that does not contain a structure that reacts with an epoxy group in the modified ethylene-α olefin. Polymer) and aromatic-modified terpene resins are preferred. Among them, aromatic-modified terpene resins are more preferred from the viewpoint of wettability, handling properties, and heat resistance, and styrene-modified terpene resins are particularly preferred from the viewpoint of availability.
Because terpene phenol resin and rosin resin are difficult to have low acid value and low hydroxyl value due to their structure, fish eyes and gel increase due to reaction with epoxy groups in melt-kneaded and modified resins In addition, the resin composition tends to thicken and the film moldability tends to be poor. From the viewpoints of adhesion at low temperature processing, heat resistance, and handling of the adhesive resin composition, the softening point by the ring and ball method is 90 ° C to 180 ° C, preferably 100 to 170 ° C, more preferably 110 to 160 ° C, and still more preferably. Is preferably in the range of 110 to 140 ° C. When the softening point is lower than 90 ° C., the heat resistance of the adhesive composition is lowered, and not only the melt-kneading with a styrene-based thermoplastic elastomer or an ethylene-α-olefin copolymer is difficult, but the adhesive The room temperature tack of the resin composition becomes too strong, making film formation difficult. Further, if the softening point is higher than 180 ° C., the adhesiveness at low temperature is inferior, which is not suitable. As a tackifier, it can use individually or in combination of 2 or more types.
The amount of the tackifier (D) is preferably 1 to 60 parts by weight. More preferably, it is 10-55 weight part, More preferably, it is 20-55 weight part. When the amount is less than 1 part by weight, the adhesive strength may be low, which is not preferable. Further, when it exceeds 60 parts by weight, the cohesive force of the composition becomes poor, the heat resistance is lowered, and the tack of the resin composition becomes too strong, making it difficult to handle during granulation and molding, It is not preferable.
(Storage modulus G ′ of polyolefin resin composition for hot melt adhesive)
The storage elastic modulus G ′ at 80 ° C. of the polyolefin resin composition for hot melt adhesive of the present invention is preferably 0.8 MPa or more, more preferably 0.9 MPa or more, and further preferably 1.0 MPa or more. is there. Those less than 0.8 MPa are unsuitable from the viewpoint of heat resistance.
The storage elastic modulus G ′ at 110 ° C. of the polyolefin resin composition for hot melt adhesive is preferably 0.8 MPa, more preferably less than 0.6 MPa, and further preferably less than 0.5 MPa. . When it is 0.8 MPa or more, it is unsuitable from the viewpoint of wetting to the base material at the time of adhesion at a low temperature. The storage elastic modulus G ′ is measured with a dynamic viscoelasticity measuring device under conditions of a shear mode, a measurement frequency of 10 Hz, and a heating rate of 4 ° C./min.

(Method for producing adhesive resin composition)
As a method for producing the polyolefin resin composition for a hot melt adhesive of the present invention, any known method may be used, but melt kneading is particularly preferable from the viewpoint of easy uniform mixing. . As an apparatus for melt kneading, a single-screw or multi-screw extruder, a Banbury mixer, a plast mill, a heated roll kneader, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder equipped with a pressure reducing device is preferable. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.
The polyolefin resin composition for hot melt adhesives of the present invention may contain other thermoplastic resins, antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers as necessary. , Stabilizers such as optical brighteners, metal soaps, antacid adsorbents, or crosslinking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing materials, pigments, dyes, flame retardants, antistatic agents Additives such as may be added within a range not impairing the effects of the present invention.
When these stabilizers and additives are used, they may be added to the styrene-based thermoplastic elastomer or the ethylene-α olefin copolymer in advance, and the ethylene-α olefin copolymer may be melt-modified. The ethylene-α olefin copolymer (A), the ethylene-α olefin copolymer (B), the styrene-based thermoplastic elastomer (C), and the tackifier (D) may be added. It may be added when each component is melt-kneaded, or may be added by an appropriate method after producing the adhesive resin composition.

(Method for producing hot melt adhesive film)
The polyolefin resin composition for hot melt adhesives of the present invention can be made into a film-like molded body (hot melt adhesive film) having heat-welding properties. Although thickness should just be adjusted suitably according to a use, it is preferable that it is 20-200 micrometers from a viewpoint that desired adhesiveness and heat resistance are easy to be obtained, Furthermore, it is preferable that it is 30-100 micrometers. The heat-weldability referred to in the present invention refers to the property of melting with heat and joining to the adherend. The production method of the hot melt adhesive film of the present invention is not particularly limited. For example, after the adhesive resin composition of the present invention is obtained by melt kneading, various extrusion molding machines, injection molding machines, and calendar moldings are used. It can be formed into a film using a machine, an inflation molding machine, a roll molding machine, or a hot press molding machine.
By using the polyolefin resin composition for hot melt adhesive of the present invention, it becomes possible to obtain a multilayer laminate by bonding various adherends at a relatively low processing temperature. Materials that can be bonded to the polyolefin resin composition for hot melt adhesives of the present invention include cellulosic polymer materials such as paper, cotton, hemp, cloth, and wood board, polyolefin resins such as polypropylene and polyethylene, polystyrene, and styrene. -Butadiene block copolymer (SBS resin), styrene-acrylonitrile copolymer (AS resin), acrylonitrile-ethylene / propylene-styrene copolymer (AES resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), etc. Styrene resins, polycarbonate resins, (meth) acrylic resins, polyester resins, polyamide resins such as nylon and polyurethane, synthetic polymer materials such as phenol resins and epoxy resins, gold, silver, copper, iron, tin , Lead, aluminum and other metal materials And the like. Two or more different materials may be mixed and combined as the material of the adherend. Further, when the laminate is formed by adhering two different adherends through an adhesive layer made of the polyolefin resin composition for hot melt adhesive of the present invention, the two adherends are constituted. The material may be the same type of material or a different type of material. The polyolefin-based resin composition for hot melt adhesive of the present invention is capable of strong adhesion without particularly subjecting the surface of the adherend, but if necessary, surface modification by plasma or laser, Surface treatment such as surface oxidation and etching may be performed.

  The laminate thus obtained can be used for the following applications, for example. Applications using skin materials and molded articles as adherends, such as interior materials for automobiles (ceiling materials for automobile interiors, door members for automobile interiors, dashboard members for automobile interiors, instrument panels, etc.), home appliance parts (computer housings, It can be suitably used as a frame of a thin television, etc.) and a housing material (interior wall board, decorative film, etc.). The skin material used here is a film, sheet, foam, various non-woven fabrics, woven fabrics, for example, a polymer decorative sheet manufactured from polyvinyl chloride, various polyolefins, ABS, for example. Polyester non-woven fabric, raised knit, fabric, polyurethane leather, polypropylene, polyethylene, polybutylene, and polyolefin-based foams produced mainly from copolymers of these olefins. In addition, as molded products used here, ABS, PC / ABS, polyolefin, glass fiber reinforced polyolefin, injection molded products of various polymer materials such as glass fiber reinforced nylon, wood chips, wood powder, etc. are thermosetting resins. And wood molded products and wood boards hardened by hot press molding with polyolefin resin. The polyolefin resin composition for hot melt adhesives of the present invention can be strongly bonded at a relatively low temperature of about 100 to 130 ° C. without damaging the texture and feel of the material of the skin material and the molded product. It can be manufactured and is suitable for the use of a molded article decoration using a decorative sheet as a skin material.

In producing a multilayer laminate that adheres a skin material such as a decorative sheet and a molded product that is a base material through an adhesive layer made of a polyolefin resin composition for a hot melt adhesive of the present invention, a thermal laminate, Various forming methods such as vacuum forming, vacuum / pressure forming, hot pressing, hot roll and hot stamping can be employed. Among these, vacuum forming, vacuum pressure forming, and hot stamping are preferable in that they can be applied to the bonding of a molded product having a skin material and a rounded shape. A molded product having a round shape refers to a molded product having a plane arc-shaped surface as a surface to be bonded to a skin material among molded products of the materials exemplified above, and is a shape skeleton of an automobile interior or home appliance housing. This is a molded product. As a manufacturing method of a laminated body, for example, an adhesive film is heated and laminated on a skin material, and this is applied to each molding, whereby the skin material can be laminated along the shape of the molded body. A hot press or a hot roll is not preferable because it may impair the arc shape of such a molded product. In particular, in vacuum / pressure forming, the skin material can be wound from the end of the molded product to the back side of the molded product by applying compressed air pressure when the skin and the molded product are bonded. A laminate having the product as an adherend can also be applied to production.
In the case of using vacuum forming, vacuum pressure forming, or hot stamping, the thickness of the adhesive film is preferably 25 μm to 100 μm, more preferably 30 μm to 75 μm, from the followability of the skin material to the molded product. If it is less than 25 μm, the adhesion area to the molded product becomes poor and the adhesive strength becomes insufficient, which is not preferable. If it exceeds 100 μm, the thermal conductivity is lowered, and the skin material is not sufficiently softened within a predetermined time during heating. , The adhesive strength decreases. In addition, by this thickness, not only a laminate having a good appearance can be obtained, but also when the laminate is placed in a high-temperature atmosphere, the skin material and the molded product are expanded and contracted. It is possible to suppress the appearance defects such as turning and lateral slippage. The laminate obtained by vacuum / pressure forming can maintain the appearance in a higher temperature atmosphere because the skin material is wound from the end of the molded product to the back surface.

  Hereinafter, the present invention will be described in more detail by way of specific examples and comparative examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

(Graft amount analysis)
Regarding the measurement of the graft amount, the obtained modified ethylene-propylene copolymer pellets were dissolved in xylene heated to 110 ° C., and then the xylene solution was dropped into N, N-dimethylformamide to cause reprecipitation. The obtained reprecipitate was obtained by titration. Titration was performed by quantifying epoxy groups by titration with perchloric acid using a potentiometric titrator (AT-700, manufactured by Kyoto Electronics Industry Co., Ltd.) according to JIS K7236.

(Measurement of melting point)
Using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DTG-50), the sample was heated to 220 ° C. at 10 ° C./min in a nitrogen atmosphere, then cooled to 40 ° C., and then 220 ° C. From the melting endothermic curve obtained when the temperature was raised again at 10 ° C./min until, the temperature defined as the peak top of the observed peak was taken as the melting point.

(Measurement of storage modulus G ')
A dynamic viscoelasticity measuring apparatus (IT measurement) under the conditions of a shear mode, a measurement frequency of 10 Hz, a heating rate of 4 ° C./min, and a measurement temperature range of −70 to 150 ° C. The measurement was carried out with DVA-200 manufactured by Control Co., Ltd., and the storage elastic moduli G ′ at 80 ° C. and 110 ° C. were recorded respectively.

(Preparation of adhesive sample)
A laminator (manufactured by Fuji Plastic Co., Ltd., LAMIPACKER LPD3204) was used to laminate an adhesive film on an ABS resin sheet having a thickness of 0.3 mm to obtain a skin material with an adhesive, and this skin material was then used as a vacuum laminator (Co., Ltd.). The product was bonded to the PP base material using Module Laminator LM-50x50-S (manufactured by NPC). The conditions of the vacuum laminator were adjusted as follows.
Temperature: 150 ° C., pressure: 2 atm, vacuum time: 6 seconds, press time: 16 seconds, holding time: 0 seconds At this time, the temperature of the adhesive layer rose to a range of 114 to 118 ° C.

The obtained laminate was cut to a width of 25 mm, and the skin material was peeled 180 degrees from the laminate at a tensile rate of 100 mm / min in an atmosphere at 23 ° C., and the strength (N / 25 mm) and fracture state were tested. did. It was expressed by material breakage (breakage of the ABS resin sheet of the skin material) and interface peeling (peeling of the adhesive layer from the PP base material interface of the molded product).
(Heat resistant creep test) Similarly, the laminate cut to the width of 25 mm was fixed in the oven so that the base material was in the horizontal direction, and a weight of 100 g was attached to one end of the decorative film, The state of peeling after 24 hours was evaluated in the atmosphere. At that time, the angle formed between the straight line connecting the weight and the bonding end surface and the base material is 90 degrees. The test was conducted with N = 5. As evaluation criteria, both x: N = 5 were determined with a peel distance of 10 mm or more (evaluation failure), and ◯: N = 5 was determined with a peel distance of less than 10 mm (good evaluation).

(Measurement of tensile modulus)
The adhesive resin composition was heated and pressed under the conditions of a predetermined heating temperature (200 ° C., 5 MPa) with a heating press machine (manufactured by Shinfuji Metal Industry Co., Ltd .: product name compression molding machine NSF-50). A sheet about 2 mm thick was obtained. This was cut to the size of 2 (1/3) dumbbell defined by JIS K7113, and the stress-strain was examined under the following conditions using an autograph (manufactured by Shimadzu Corporation: AGS-X). When the stresses corresponding to the two specified strains ε1 = 0.0005 and ε2 = 0.005 are σ1 and σ2, respectively, the difference in stress (σ2−σ1) is the difference in strain (ε2−ε1). The value obtained by dividing was taken as the tensile modulus, and the average value of three measurements was adopted.
Test temperature: 23 ° C., test speed: 1 mm / min, initial chuck distance: 27 mm

(Density measurement)
The density of the resin pellets was measured with a density measuring device (Mirage Trading Co., Ltd .: Hydrometer ED-120T) in accordance with JIS K7112 A method (underwater substitution method). The measurement was performed three times and the average value was adopted.

(Production Example 1)
Ethylene-propylene copolymer (Dow Chemical Japan Co., Ltd .: Versify 3000; melting point 118 ° C., density 0.891 g / cm 3, tensile elastic modulus 440 MPa, ethylene content 5%) 100 parts, 1,3-di (t- Butylperoxyisopropyl) benzene (half-life of 1 minute, 175 ° C.) 0.5 part twin screw extruder (46 mmφ, L / D = 60, manufactured by Kobe Steel, Ltd.) set at a cylinder temperature of 200 ° C. and a rotation speed of 150 rpm The product name HYPERKTX46) was supplied and melt-kneaded, and then 3 parts of glycidyl methacrylate and 3 parts of styrene were added and melt-kneaded from the middle of the cylinder to obtain a modified ethylene-propylene copolymer A1. The graft amount of glycidyl methacrylate in the obtained modified ethylene-propylene copolymer A1 was 0.8 wt%.
The physical properties (density, melting point, tensile elastic modulus, graft amount, ethylene content) of the modified ethylene-α olefin copolymer A1 obtained in the above production example and the ethylene-α olefin copolymer B1 used in the following examples are shown. It was shown in 1.

Example 1 and Comparative Examples 1-2
(1) Production of hot melt adhesive film (Example 1)
10 parts of the modified ethylene-propylene copolymer A1 obtained in Production Example 1 and 90 parts of an unmodified ethylene-propylene copolymer B1 (manufactured by Dow Chemical Japan Co., Ltd .: Versify 4301) were brought to a cylinder temperature of 180 ° C. The adhesive resin composition was obtained by melt-kneading with a set twin screw extruder (44 mmφ, L / D = 38.5, manufactured by Nippon Steel Works, product name TEX44XCT). This adhesive resin composition was formed into a film having a thickness of 60 μm by a T-die to obtain a hot melt type adhesive film, and the results of evaluation according to the items of the adhesion evaluation and the heat resistance test are shown in Table 2.
(Comparative Example 1)
100 parts of the modified ethylene-propylene copolymer A1 obtained in Production Example 1 was formed into a film having a thickness of 60 μm with a T-die to obtain a hot melt adhesive film, which was evaluated according to the above-described adhesion evaluation and heat resistance test items. The results are shown in Table 2.
(Comparative Example 2)
An unmodified ethylene-propylene copolymer B1 (manufactured by Dow: Versify 4301) was formed into a film having a thickness of 60 μm using a T-die to obtain a hot-melt adhesive film, and the results evaluated in accordance with the items of the above-described adhesion evaluation and heat test are shown in Table 1. 2.

Claims (12)

The polyolefin resin composition for hot melt adhesives containing the following (A) and (B).
5 to 95 parts by weight of an ethylene-α olefin copolymer (A) having a melting point of 100 ° C. or more and less than 130 ° C., 95 to 5 parts by weight of an ethylene / α olefin copolymer having a melting point of 130 to 160 ° C. Polymer (B) (here, (A) and (B) are combined to make 100 parts by weight).   The polyolefin system for hot melt adhesive according to claim 1, further comprising 1 to 60 parts by weight of a styrenic thermoplastic elastomer (C) with respect to a total of 100 parts by weight of (A) and (B). Resin composition.   The polyolefin system for hot melt adhesive according to claim 1 or 2, further comprising 1 to 60 parts by weight of a tackifier (D) with respect to 100 parts by weight of the total of (A) and (B). Adhesive resin composition.   The storage elastic modulus G ′ (80) measured in a shear mode at a frequency of 10 Hz at 80 ° C. is 0.8 MPa or more, and the storage elastic modulus G ′ (110) measured in a shear mode at a frequency of 10 Hz at 110 ° C. is less than 0.8 MPa. The polyolefin resin composition for hot melt adhesives according to any one of claims 1 to 3, wherein the polyolefin resin composition is for hot melt adhesives.   The tensile elastic modulus of the ethylene-α-olefin copolymer (A) is from 300 MPa to 700 MPa, and the tensile elastic modulus of the ethylene-α-olefin copolymer (B) is from 10 MPa to 200 MPa. Item 5. A polyolefin resin composition for a hot melt adhesive according to any one of Items 1 to 4.   The (A) and / or (B) is a modified ethylene-α olefin copolymer graft-modified with (a) an unsaturated carboxylic acid or derivative thereof and (b) an aromatic vinyl monomer. The polyolefin resin composition for hot melt adhesives according to any one of claims 1 to 5.   The polyolefin resin composition for a hot melt adhesive according to any one of claims 1 to 6, wherein (A) and / or (B) is an ethylene-propylene copolymer.   The polyolefin resin composition for a hot melt adhesive according to any one of claims 1 to 7, wherein the ethylene content in the (A) and / or (B) is 3 to 20% by weight.   The polyolefin resin composition for a hot melt adhesive according to any one of claims 1 to 8, wherein the styrene thermoplastic elastomer has a styrene content of 20% by weight or less.   The styrenic thermoplastic elastomer is at least one selected from a hydrogenated styrene-isoprene block copolymer, a hydrogenated styrene-butadiene block copolymer, and a hydrogenated styrene-butadiene random copolymer. The polyolefin resin composition for hot melt adhesives according to any one of the above.   The polyolefin system for hot melt adhesive according to any one of claims 1 to 10, wherein the tackifier is any one of a terpene resin, an aromatic modified terpene resin, and an alicyclic petroleum resin. Resin composition. A hot-melt adhesive film comprising the polyolefin-based resin composition for hot-melt adhesives according to any one of claims 1 to 11 and having a thickness of 20 to 200 µm.