JP2014148622A - Resin for hot-melt adhesive film having reduced fish eyes, method for producing the same, hot-melt adhesive film comprising resin, and laminate comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-melt adhesive film comprising a modified polyolefin resin, which can suppress poor appearance caused by irregularities derived from fish eyes of the adhesive layer.SOLUTION: A hot-melt adhesive film with reduced fish eyes can be produced by using a resin obtained from monomers of a specific composition ratio when an aromatic vinyl monomer and a polar group-containing vinyl monomer are grafted to a polyolefin. When a laminate is formed using the film, irregularities derived from fish eyes do not appear on a design surface and it is possible to suppress poor appearance of the laminate.

Description

  The present invention relates to an adhesive film made of a modified polyolefin resin having a small amount of fish eyes, and can be suitably used for a laminate in which appearance defects caused by the fish eye-derived irregularities of the adhesive layer are suppressed.

  Thermoplastic resins such as thermoplastic elastomers, olefin polymers, vinyl polymers, and engineering plastics are excellent in physical properties, moldability, surface properties, etc., so they are used in fields such as automobiles, electrical / electronics, architecture, and miscellaneous goods. Therefore, it is molded and used by processing methods such as extrusion molding, injection molding, and press molding. These molded products are often combined by bonding a plurality of molded products in order to obtain products having a desired shape, or to enhance performance and diversify functions. A modified olefin resin is used as such a heat-melt type (hot melt type) adhesive that is simple and excellent in adhesive strength.

  In recent years, not only adhesion of the same kind of thermoplastic resin but also adhesion of different types of thermoplastic resin or thermoplastic resin to metal or glass, metal to metal, or metal to glass is required. In particular, when a metal member is used, if there is a defect such as fish eye in the adhesive layer, a convex defect or the like may occur on the design surface, which may lead to poor appearance.

  As a method for producing a modified olefin resin in which the generation of such fish eyes is suppressed, for example, in Patent Document 1, an antioxidant is added to an olefin polymer containing a functional monomer such as maleic anhydride and a radical initiator. Methods and Patent Document 2 include a method of adding a solution of an unsaturated carboxylic acid and a radical generator dissolved in a solvent to an olefin polymer in a molten state. However, these methods have a problem that if the fish eye is reduced, sufficient denaturation cannot be performed.

Patent Document 3 describes a method of supplying a modified ethylene polymer composition excellent in adhesion to a metal or polar resin with reduced fish eyes, and has a major axis of 0.2 mm or more present in the film. Although it is described that the number of fish eyes is 30 pieces / g or less, it is the fish eye that protrudes from the surface of the adhesive film that causes poor appearance when laminated, and the height from the film surface Is important, but there is no mention of that.
Also, as in JP 2000-063602, when modification is performed using a plurality of monomers, the fish eye may increase depending on the monomer composition ratio, so the monomer composition ratio is important. There is no description.

JP-A-7-216032 JP-A-9-202846 JP2005-036221 JP2000-063602

  The present invention relates to a resin for hot melt adhesive film with reduced fish eyes and a method for producing the same, and an object of the present invention is to provide a laminate in which appearance defects can be suppressed by using a hot melt adhesive film made of the resin. And

  As a result of intensive studies in view of the above-mentioned present situation, the present inventors have obtained by modifying the aromatic vinyl monomer and the polar group-containing vinyl monomer at a specific monomer composition ratio when grafting to the polyolefin. The present inventors have found that a hot melt adhesive film with reduced fish eyes can be produced by using the obtained resin, and have completed the following present invention.

  That is, the present invention has the following configuration.

1). A hot melt adhesive film comprising a modified polyolefin resin obtained by modifying a polyolefin resin (a) with (b), (c) and (d), wherein the composition ratio of (c) and (d) is (1) is satisfied, the MFR of (a) and the modified polyolefin resin satisfies the following formula (2), and there is no fish eye having an elevation difference of 25 μm or more represented by the following formula (3) in the film 10 cm × 50 cm. A hot melt adhesive film.
(A) 100 parts by weight of a polyolefin resin,
(B) 0.01 parts by weight to 5 parts by weight of a radical polymerization initiator,
(C) Aromatic vinyl monomer 0.1 to 10 parts by weight (d) Epoxy group-containing vinyl monomer 0.1 to 10 parts by weight Number of parts by weight of (d) ≦ In (part by weight of (C)) + 2 .48 (1)
MFR of modified polyolefin resin ≧ 0.5 × (MFR of (a)) (2)
Elevation difference = (fisheye height in the thickness direction)-(film thickness) (3)
2). The adhesive film for hot melt according to 1), wherein the epoxy group-containing vinyl monomer is glycidyl (meth) acrylate.

3). The adhesive film for hot melt as described in 1) to 2), wherein the number of fish eyes is 8 / cm ² or less.

  4). 1) to 3) A laminate containing the hot melt adhesive film according to any one of the above.

  5). 1) -4) The manufacturing method of modified polyolefin resin for adhesive films for hot melts as described in any one.

  When a laminate is prepared using a hot melt adhesive film with reduced fish eyes in the present invention, the irregularities derived from fish eyes do not appear on the design surface, and it is possible to suppress poor appearance of the laminate.

≪Polyolefin resin≫
In the present invention, the polyolefin resin before graft modification (hereinafter referred to as raw material polyolefin resin) is, for example, any ratio of polyethylene, polypropylene, poly-1-butene, polyisobutylene, propylene and ethylene and / or 1-butene. A random copolymer or a block copolymer, an ethylene-propylene-diene terpolymer having a diene component of 50% by weight or less at any ratio of ethylene and propylene, polymethylpentene, cyclopentadiene and ethylene, and / or Examples thereof include cyclic polyolefins such as copolymers with propylene, random copolymers of ethylene or propylene and vinyl compounds of 50% by weight or less, block copolymers, and the like.

Among these, olefin-based elastomers are preferably used from the viewpoint of improving the adhesion between the adhesive film and the substrate described later. The olefin elastomer is an α-olefin polymer or copolymer having 2 to 20 carbon atoms, and specifically includes an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, and an ethylene / 1-hexene. Copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / 1-octene copolymer, propylene homopolymer, propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, 1- Butene homopolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer, 4-methylpentene-1 homopolymer, 4-methylpentene-1 / propylene copolymer, 4-methylpentene- 1,1-butene copolymer, 4-methylpentene-1, propylene / 1-butene copolymer, propylene / 1-butene copolymer, ethylene Vinyl acetate copolymer, ethylene-methacrylic acid copolymer, methyl ethylene-methacrylic acid copolymers. A propylene homopolymer, a propylene / ethylene copolymer, and a propylene / 1-butene copolymer are preferable. Particularly preferred is a propylene / ethylene copolymer.
If necessary, another resin or rubber may be added to the raw material polyolefin resin as long as the effects of the present invention are not impaired.

  Examples of the other resin or rubber include poly α-olefins such as polypentene-1 and polymethylpentene-1, ethylene such as propylene / butene-1 copolymer having a propylene content of less than 75% by weight, or α- Olefin / α-olefin copolymer; ethylene or α-olefin / α-olefin / diene monomer copolymer such as ethylene / propylene / 5-ethylidene-2-norbornene copolymer having a propylene content of less than 75% by weight Polymer; Polydiene copolymer such as polybutadiene and polyisoprene; Vinyl monomer / diene monomer random copolymer such as styrene / butadiene random copolymer and styrene / isoprene random copolymer; Styrene / butadiene / styrene block Copolymer, styrene / isoprene / styrene block copolymer Vinyl monomer such as polymer / diene monomer / vinyl monomer block copolymer; Hydrogenation (styrene / butadiene random copolymer), hydrogenation (styrene / isoprene random copolymer), etc. (Vinyl monomer / diene monomer random copolymer); hydrogenation (styrene / butadiene / styrene block copolymer), hydrogenation (styrene / isoprene / styrene block copolymer), etc. Monomer / diene monomer / vinyl monomer block copolymer); vinyl monomer / diene monomer such as acrylonitrile / butadiene / styrene graft copolymer, methyl methacrylate / butadiene / styrene graft copolymer / Vinyl monomer graft copolymer; polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, poly Vinyl polymers such as ethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polystyrene; vinyl chloride / acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonitrile / styrene copolymer, methyl methacrylate / styrene Examples thereof include vinyl copolymers such as copolymers.

  The amount of addition of these other resins or rubber to the raw polyolefin resin is different depending on the type of this resin or the type of rubber, and as long as it is within the range not impairing the effects of the present invention as described above, It is preferably about 25% by weight or less.

  The raw material polyolefin resin (which may contain various additive materials) may be in the form of particles or pellets, and the size and shape are not particularly limited.

In addition, when the above additive material (other resin and rubber) is used, this additive material is added when the raw polyolefin resin is melted even if it is previously added to the raw polyolefin resin. It may be a thing.
Regarding the propylene component in the raw material polyolefin resin, it is preferable that the propylene unit is a majority amount in that radicals are easily generated in the raw material polyolefin resin. The majority amount here means that the propylene component with respect to the polyolefin resin is 50% by weight or more.

≪Aromatic vinyl monomer≫
When an aromatic vinyl monomer is used, molecular chain scission is suppressed during grafting to a molecular chain-breaking polyolefin such as polypropylene, and a high ratio of epoxy group-containing vinyl monomers is maintained while maintaining a high molecular weight. It is preferable because it can be introduced.
Examples of aromatic vinyl monomers include styrene; methyl styrene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, β-methyl styrene, dimethyl styrene, and trimethyl styrene; o -Chlorostyrene such as chlorostyrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, trichlorostyrene; o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromo Bromostyrene such as styrene and tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene, and trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitrostyrene Nitrostyrenes such as dinitrostyrene and trinitrostyrene; vinylphenols such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene and trihydroxystyrene; o-divinylbenzene, m-divinylbenzene and p-divinyl 1 type, or 2 or more types, such as divinylbenzene, such as benzene; diisopropenylbenzene, such as o-diisopropenylbenzene, m-diisopropenylbenzene, and p-diisopropenylbenzene; Among these, methylstyrene such as styrene, α-methylstyrene, and p-methylstyrene is preferable because it is inexpensive, and it is preferable because unreacted substances can be easily removed. If unreacted substances remain, it may cause fish eyes during film production.

  The amount of the aromatic vinyl monomer added is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the polyolefin resin. It is especially preferable that it is 0.0-5.0 weight part. If the amount added is too small, the graft ratio of the epoxy group-containing vinyl monomer to the polyolefin resin tends to be poor. On the other hand, when the addition amount exceeds 10 parts by weight, the graft efficiency of the epoxy group-containing vinyl monomer monomer reaches the saturation range.

≪Epoxy group-containing vinyl monomer≫
Examples of the epoxy group-containing vinyl monomer include glycidyl methacrylate, glycidyl acrylate, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconate, diglycidyl itaconate, monoglycidyl allyl succinate, diglycidyl allyl succinate, p-styrene. Such as glycidyl carboxylate, allyl glycidyl ether, methallyl glycidyl ether, styrene-p-glycidyl ether, p-glycidyl styrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, etc. 1 type, or 2 or more types, such as an epoxy olefin and vinylcyclohexene monoxide, are mentioned.

  Among these, glycidyl methacrylate and glycidyl acrylate are preferable in that they are inexpensive, and are preferable in that removal of unreacted materials is easy. If unreacted substances remain, it may cause fish eyes during film production.

  The addition amount of the epoxy group-containing vinyl monomer is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the polyolefin resin. It is particularly preferably 1.0 to 5.0 parts by weight. Moreover, it is necessary to satisfy | fill Formula (1). When the amount is more than 10 parts by weight or when the formula (1) is not satisfied, a monomer not involved in grafting may cause a polymerization reaction in the resin and cause fish eyes. Moreover, when there is too little addition amount, there exists a tendency for a graft rate to be inferior.

  A modified polyolefin can be obtained by reacting the raw material polyolefin resin, the aromatic vinyl monomer, and the epoxy group-containing vinyl monomer by heating in the presence of a radical polymerization initiator.

≪Radical polymerization initiator≫
Examples of radical polymerization initiators include organic peroxides and azo compounds. Illustrative examples include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t- Peroxyketals such as butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; permethane hydroperoxide, 1 , 1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, etc .; dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butyl Peroxy) hexane, α, α′-bis ( -Butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, dialkyl such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 Peroxides; diacyl peroxides such as benzoyl peroxide; peroxydicarbonates such as di (3-methyl-3-methoxybutyl) peroxydicarbonate and di-2-methoxybutylperoxydicarbonate; t-butylperoxy Octate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate, 2,5-dimethyl -2,5-di (benzoylperoxy) hexa , T- butyl peroxy acetate, t- butyl peroxybenzoate, one or more organic peroxides such as peroxy esters such as di -t- butyl peroxy isophthalate and the like.

  Of these, those having a particularly high hydrogen abstraction ability are preferred. Examples of such radical polymerization initiators include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1. Peroxyketals such as 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, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di Dialkyl peroxides such as t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; Diacyl peroxides such as nzoyl peroxide; t-butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butylperoxy-3,5,5-trimethylhexano Ate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxyiso 1 type, or 2 or more types, such as peroxyesters, such as a phthalate, is mention | raise | lifted.

  The addition amount of the radical polymerization initiator is preferably in the range of 0.01 to 10 parts by weight and more preferably in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the polyolefin resin. Preferably, 0.3 to 2 parts by weight is particularly preferable. 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, fluidity may be lowered due to a crosslinking reaction or mechanical properties may be lowered due to molecular chain breakage.

≪Modified polyolefin resin≫
The modified polyolefin resin in the present invention is a resin obtained by graft-modifying a polyolefin resin using an aromatic vinyl monomer and an epoxy group-containing vinyl monomer.
The modified polyolefin resin in the present invention has a melting point of 120 ° C. or higher, preferably 125 ° C. or higher and 165 ° C. or lower, more preferably 130 ° C. or higher and 160 ° C. or lower. When the melting point is less than 120 ° C., the heat resistance required for automobile members and the like is insufficient, and the metal member and the molded member may peel off in a high temperature atmosphere. Moreover, when melting | fusing point is higher than 165 degreeC, manufacture of raw material polyolefin resin is technically difficult.

  The modified polyolefin resin in the present invention has a heat of fusion of 15 J / g or less, preferably 0.1 J / g or more and 12 J / g or less, more preferably 0.2 J / g or more and 10 J / g or less. If the amount of heat of fusion exceeds 15 J / g, the initial adhesiveness between the adhesive film layer and the substrate in contact with the adhesive film layer cannot be sufficiently obtained, and the working efficiency is greatly reduced, such as difficulty in positioning. Moreover, it is technically difficult to produce a raw material polyolefin resin having a heat of fusion of less than 0.1 J / g. The melting point and heat of fusion can be determined, for example, by differential scanning calorimetry (DSC).

  The melting point and heat of fusion of the modified polyolefin resin can be easily achieved by using a raw material polyolefin resin having the characteristics.

  The MFR of the modified polyolefin resin is preferably 0.5 times or more of the MFR of the polyolefin resin before modification, more preferably 0.8 times or more, and particularly preferably 1.0 times or more. If the MFR of the modified polyolefin is low, the die temperature must be increased during film production, which causes fish eyes.

  The MFR of the modified polyolefin is preferably 4 or more and 200 or less, more preferably 5 or more and 100 or less, and particularly preferably 6 or more and 80 or less. If the MFR is higher than 200, the neck-in of the film extruded from the die at the time of film production becomes large, and there is a possibility that a predetermined film width cannot be produced.

  If necessary, the modified polyolefin resin may contain antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers, fluorescent brighteners, metal soaps, antacid adsorbents, Or additives such as a cross-linking agent, chain transfer agent, nucleating agent, lubricant, plasticizer, filler, reinforcing material, pigment, dye, flame retardant, antistatic agent, etc. may be added within a range not impairing the effects of the present invention. Also good. When these stabilizers and additives are used, they may be added to the raw material polyolefin resin in advance, or may be added when the raw material polyolefin resin is graft-modified. After the resin is produced, it may be added to the modified polyolefin resin by an appropriate method.

  Furthermore, the modified polyolefin resin can also be used by mixing with other thermoplastic resins.

  Examples of the thermoplastic resin mixed with the modified polyolefin resin include polypropylene homopolymer, high density polyethylene, low density polyethylene, linear low density polyethylene, poly-1-butene, polyisobutylene, polypentene-1, polymethylpentene- Poly α-olefins such as 1; ethylene or α-olefin / α-olefin copolymers such as propylene / butene-1 copolymer having a propylene content of less than 75% by weight; ethylene having a propylene content of less than 75% by weight Ethylene / α-olefin / α-olefin / diene monomer copolymer such as / propylene / 5-ethylidene-2-norbornene copolymer; polydiene copolymer such as polybutadiene and polyisoprene; styrene / butadiene random copolymer Coalescence, styrene / isoprene random Vinyl monomers such as copolymers / Random copolymers of diene monomers; Vinyl monomers / diene monomers such as styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers / Vinyl monomer block copolymer; Hydrogenation (vinyl monomer / diene monomer random copolymer) such as hydrogenation (styrene / butadiene random copolymer), hydrogenation (styrene / isoprene random copolymer), etc. ); Hydrogenation (Styrene / Butadiene / Styrene block copolymer), Hydrogenation (Styrene / Isoprene / Styrene block copolymer), etc. (Vinyl monomer / Diene monomer / Vinyl monomer block copolymer) Polymer); acrylonitrile / butadiene / styrene graft copolymer, methyl methacrylate / butadiene / styrene graft copolymer Vinyl monomer / diene monomer / vinyl monomer graft copolymer; polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, ethyl polyacrylate, polybutyl acrylate, polymethacrylic acid Vinyl polymers such as methyl and polystyrene; vinyl copolymers such as vinyl chloride / acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonitrile / styrene copolymer, methyl methacrylate / styrene copolymer, etc. These can be used alone or in admixture of two or more.

  Among these, since it has high heat resistance when it is used as an adhesive film and it is easy to maintain surface adhesion, vinyl monomers such as styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers, etc. / Diene monomer / vinyl monomer block copolymer, hydrogenation (styrene / butadiene / styrene block copolymer), hydrogenation (styrene / isoprene / styrene block copolymer), etc. (vinyl) Monomer / diene monomer / vinyl monomer block copolymer) is preferred.

  The blending amount of the thermoplastic resin mixed with the modified polyolefin resin is preferably 0.1 to 50 parts by weight with respect to 100 parts by weight of the modified polyolefin resin from the viewpoint of adhesiveness when used as an adhesive film, and more preferably 0. .1 to 30 parts by weight is preferable.

  Moreover, in this invention, you may mix | blend a tackifier for the purpose of improving the surface adhesive force of an adhesive film. Examples of the tackifier include rosin resins (gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, etc.), terpene phenol resin, terpene resin (α -Polymers such as pinene, β-pinene and limonene), aromatic hydrocarbon modified terpene resins, petroleum resins (aliphatic, alicyclic, aromatic, etc.), coumarone / indene resins, styrene resins, phenols Resins (alkyl phenol, phenol xylene formaldehyde, rosin-modified phenol resin, etc.), xylene resins and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, from the viewpoint of thermal stability, rosin resin, terpene phenol resin, terpene resin, aromatic hydrocarbon modified terpene resin, petroleum resin, hydrogenated petroleum resin are preferable, and are compatible with the modified polyolefin resin of the present invention. And since it can contribute also to adhesion | attachment with polar resin, rosin-type resin and terpene phenol resin are especially preferable.

  The blending amount of the tackifier mixed with the modified polyolefin resin is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the modified polyolefin resin from the viewpoint of heat resistance of the adhesive film. 30 parts by weight is preferred.

  As the polymerization reaction for graft modification used in the present invention, melt polymerization is used.

  The melt polymerization is a method in which a raw material polyolefin resin, a radical polymerization initiator, an aromatic vinyl monomer, and an epoxy group-containing vinyl monomer are kneaded while the polyolefin resin is melted.

  As the melt kneading apparatus, an extruder, a Banbury mixer, a mill, a kneader, a heating roll, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder is preferred. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.

  The aromatic vinyl monomer and the epoxy group-containing vinyl monomer may be added simultaneously or separately. When adding separately, it is more preferable to add an epoxy group containing vinyl monomer after adding an aromatic vinyl monomer.

  The heating temperature at the time of melt kneading is 100 to 230 ° C., that the polyolefin resin and the radical polymerization initiator remain in a sufficiently melted state and do not undergo thermal decomposition, and ring-opening polymerization of epoxy groups does not proceed. It is preferable and 150-220 degreeC is especially preferable.

≪Hot melt adhesive film≫
The thickness of the hot melt adhesive film of the present invention is preferably 30 μm to 300 μm, more preferably 50 μm to 200 μm from the viewpoint of handling.

  The material of the adherend used in the present invention is, for example, a material that can adhere to the adhesive resin layer of the adhesive film of the present invention. Specifically, for example, metals such as gold, silver, copper, iron, tin, lead, aluminum and silicon; inorganic materials such as glass and ceramics; cellulosic polymer materials such as paper and cloth; melamine resin, acrylic Examples thereof include synthetic polymer materials such as urethane resin, urethane resin, (meth) acrylic resin, styrene / acrylonitrile copolymer, polycarbonate resin, phenol resin, polyester resin, epoxy resin, and silicon resin.

  Two or more different materials may be mixed and combined as the material of the adherend. When the laminate is formed by adhering two different adherends via the adhesive film of the present invention, the materials constituting the two adherends may be the same type of material but different types. Any of the materials may be used. The property of the adherend is not particularly limited, and examples thereof include a film shape, a sheet shape, a plate shape, and a fiber shape. In addition, the adherend may be subjected to a surface treatment such as a release agent, a coating such as plating, a coating with a paint, surface modification with plasma or laser, surface oxidation, etching, etc., if necessary. Good. Specific examples of adherends include automotive parts such as trims (door trims, interior trims, etc.), molded ceilings, sheet materials (interior sheets, instrument panel skins, decorative sheets, etc.), indoor doors, partitions, interior wall panels, Examples include, but are not limited to, decorative films used in housing materials such as furniture and system kitchens.

≪Fisheye≫
The fish eye of the present invention refers to an unmelted high molecular weight product generated when a resin present in a film is modified, and has a major axis of 40 μm or more.
The elevation difference of the fish eye of the hot melt adhesive film of the present invention needs to be less than 25 μm, preferably less than 20 μm, more preferably less than 10 μm, and particularly preferably 0 μm. If there is even one fish eye with an altitude difference of 25 μm or more, a convex defect is formed on the design surface when a laminate is produced, leading to poor appearance. The smaller the number of fish eyes, the better, preferably 8 / cm ² or less, more preferably 4 / cm ² or less, particularly preferably ² / cm ² or less, and most preferably 0 / cm ² . If the number of fish eyes is more than 8 / cm ² , the appearance of the film is impaired, which is not preferable as a product.

  Specific examples are shown below, 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.

[Measurement of MFR]
Based on JIS K7210, MFR in 230 degreeC and a 2.16kg load was measured.

[Measurement of fisheye elevation difference]
A hot melt adhesive film 10 cm × 50 cm is cut out, and the height in the film thickness direction of the fish eye in the film is measured using a film thickness meter. Moreover, the film thickness of the film of a part without a fish eye is measured. Each measurement was performed 3 times and the average value was used. Substituting those values into the following formula, the elevation difference is calculated.

Elevation difference = (fisheye height in the thickness direction)-(film thickness)
Film thickness gauge: Mitutoyo Upright Gauge (digital type)
Scale: 0.001 mm, Measuring element: Flat measuring element [Measurement of the number of fish eyes]
Cut out a 10 cm x 10 cm hot melt adhesive film and randomly place 3 marks of 1 cm x 1 cm. Observe the marked part with a microscope and count the number of fish eyes derived from the resin. The number of fish eyes is the average of three locations.

Microscope used: VHX900 manufactured by Keyence Corporation
Example 1
100 parts of polypropylene ethylene rubber (Versify 3401.05 made by Dow Chemical, MFR = 7.5 g / 10min), 0.3 part of 1,3-di (t-butylperoxyisopropyl) benzene (manufactured by NOF: perbutyl P) After supplying from a mouth to a twin screw extruder (46 mmφ, L / D = 63, manufactured by Kobe Steel Co., Ltd.) set at a cylinder temperature of 200 ° C. and a screw rotation speed of 150 rpm, melted and kneaded, then 1 part of styrene from the middle of the cylinder, After adding 1 part of glycidyl methacrylate and melt-kneading, it was further melt-kneaded at 200 ° C. to obtain modified polyolefin resin pellets.
The obtained resin pellets were put into a hopper of a single-screw extruder (product name: Labo plast mill; φ20 mm, L / D = 20) manufactured by a cylinder and a die temperature of 200 ° C. and a screw rotation speed of 100 rpm. A film having a width of about 13 cm, a length of about 60 cm, and a thickness of about 50 μm was obtained by laminating from a T-shaped die attached to the tip to a PET film subjected to a release treatment. Table 1 shows the results of counting the number of fish eyes after the obtained film was cut into a size of 1 cm × 1 cm and the release-treated PET film was peeled off.

(Example 2)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 1 part of styrene and 2 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Example 3)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 2.5 parts of styrene and 3 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Example 4)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 3 parts of styrene and 3 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Example 5)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 4 parts of styrene and 3 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Example 6)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 5 parts of styrene and 1 part of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Example 7)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 5 parts of styrene and 3.5 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Comparative Example 1)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 1 part of styrene and 3 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Comparative Example 2)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 1 part of styrene and 5 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Comparative Example 3)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 3 parts of styrene and 5 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Comparative Example 4)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 4 parts of styrene and 4 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

(Comparative Example 5)
Modified polyolefin resin pellets were obtained in the same manner as in Example 1 except that 5 parts of styrene and 5 parts of glycidyl methacrylate were used.
A film was prepared in the same manner as in Example 1, and the number of fish eyes was counted. The results are shown in Table 1.

  From the above results, the hot melt adhesive film of the present invention has a good appearance with no fisheye with an elevation difference of 25 μm or more, and thus a laminated body that suppresses the appearance defect caused by the irregularities derived from the fisheye of the adhesive layer. Is suitable.

Claims (5)

A hot melt adhesive film comprising a modified polyolefin resin obtained by modifying a polyolefin resin (a) with (b), (c) and (d), wherein the composition ratio of (c) and (d) is (1) is satisfied, the MFR of (a) and the modified polyolefin resin satisfies the following formula (2), and there is no fish eye having an elevation difference of 25 μm or more represented by the following formula (3) in the film 10 cm × 50 cm. A hot melt adhesive film.

(A) 100 parts by weight of a polyolefin resin,
(B) 0.01 parts by weight to 5 parts by weight of a radical polymerization initiator,
(C) Aromatic vinyl monomer 0.1 to 10 parts by weight (d) Epoxy group-containing vinyl monomer 0.1 to 10 parts by weight Number of parts by weight of (d) ≦ In (part by weight of (C)) + 2 .48 (1)
MFR of modified polyolefin resin ≧ 0.5 × (MFR of (a)) (2)
Elevation difference = (fisheye height in the thickness direction)-(film thickness) (3) The adhesive film for hot melt according to claim 1, wherein the epoxy group-containing vinyl monomer is glycidyl (meth) acrylate. The hot melt adhesive film according to claim 1, wherein the number of fish eyes is 8 / cm ² or less. The laminated body containing the adhesive film for hot melts as described in any one of Claims 1-3. The manufacturing method of the modified polyolefin resin for adhesive films for hot melts as described in any one of Claims 1-4.