JP3501870B2 - Multilayer heat-sensitive adhesive film and multilayer structure using the film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer heat-sensitive adhesive film having excellent adhesiveness and air barrier properties, and is particularly used as an interior material for automobiles and the like which requires both low-temperature heat-adhesiveness and high-temperature heat-resistant creep resistance at the same time. The present invention relates to a multilayer heat-sensitive adhesive film that can be suitably used as an adhesive layer of a multilayer structure, and a multilayer structure using the film.

[0002]

2. Description of the Related Art Conventionally, hot-melt type adhesives have been used in the adhesive layers of various multilayer laminates. Unlike solvent-based adhesives, hot-melt adhesives can simplify the work process during bonding, and do not cause problems such as adverse industrial hygiene and fire hazards associated with the use of organic solvents. Widely used. On the other hand, hot-melt adhesives generally have insufficient adhesive strength and are often inferior in heat creep resistance as compared with solvent-based adhesives, and it has been pointed out that the adhesiveness is insufficient depending on the application. Further, as an interior material for automobiles and the like, a multilayer structure in which a skin material and a structural material (substrate material) are laminated is often used. From the viewpoint of work efficiency, safety and hygiene, a heat-sensitive adhesive film has been increasingly used in place of the conventional solvent-based adhesive for bonding the skin material and the substrate material. These heat-sensitive adhesive films are produced by using a composition of an adhesive resin as a raw material, and various films have been developed depending on the use.

As one of the most excellent of these heat-sensitive adhesive films, there is a film containing an ethylene-based copolymer as a main component as disclosed in JP-A-5-147175, which has a wide range of skin and substrate. It can be used for plate materials and has been widely used in terms of work efficiency and performance. An ethylene-acrylic acid ester-maleic anhydride terpolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, or a low melting point ethylene-acrylic acid ester-maleic anhydride terpolymer of both outer layers used as an adhesive layer of this multilayer laminate is used. Hot-melt adhesives such as copolymerized nylon have a drawback that they are liable to sag or peel off when they are left at a high temperature (about 80 ° C.) such as the vehicle temperature under hot weather for a long time. In addition, the bonding strength can be increased by setting the heating temperature to a relatively high temperature of 120 ° C. or more during bonding, but in this case, there is a drawback that the skin material is likely to be damaged.

As a conventional lamination method for obtaining a multi-layer laminate, a method using a hot press or a heat roll, or a method using vacuum pressure bonding has been used. With the method using a hot press or a heat roll, it is possible to use a conventional heat-sensitive adhesive because a sufficient pressure can be obtained, but the vacuum pressure bonding method can obtain only a pressure of 760 mmHg / cm ² at maximum. A conventional ethylene-vinyl acetate copolymer,
A heat-sensitive adhesive such as a partially saponified ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid ester copolymer, or a copolymerized nylon yields only extremely weak adhesive strength, and a solvent-based adhesive is used. There was nothing else.

Further, depending on the application, the air permeability of the entire multilayer structure may be a problem, and improvement thereof is desired. Specifically, for example, a resin felt (hereinafter abbreviated as RF) is used as a substrate material. The cut cloth is loosened into a thread waste,
When materials such as phenol resin impregnated and hardened) and non-woven fabrics are used as the skin material, there is a problem that outside air, moisture, dust, etc. pass through the multi-layered structure and stain the interior materials in the room, impairing the appearance. is there. Originally, the heat-sensitive adhesive film is a material that is substantially impermeable to air, but it melts in the adhesive process,
In addition, it is presumed that a pinhole is formed on the entire surface of the film due to the pressure applied, and the air barrier property is deteriorated. As a countermeasure for this, it is considered that the film thickness is made sufficiently thick to prevent perforation, but in this case, the workability is lowered and the cost is increased, so it is difficult to apply it to the actual production process. is there.

[0006]

As described above, in the prior art, while maintaining the basic performance such as work efficiency, adhesiveness, and heat resistance, the air barrier property is excellent, and the low temperature adhesiveness and heat resistance are excellent. Satisfies the creep characteristics at the same time. A heat-sensitive adhesive film and an adhesive method applicable to a wider range of applications have not been established. It is an object of the present invention to solve this problem.

[0007]

Means for Solving the Problems As a result of various studies for solving the above problems, the present inventors have found that a specific ethylene-based copolymer and a polyhydric alcohol compound having at least two hydroxyl groups in the molecule, We have found that a multilayer film obtained by laminating a resin composition comprising a tackifier and a reaction accelerator and a specific polyolefin resin satisfies the object of the present invention, and completed the present invention.

That is, according to the present invention, both outer layers are (a) an ethylene-based copolymer comprising ethylene and a radical-polymerizable comonomer other than the radical-polymerizable acid anhydride and the radical-polymerizable acid anhydride. The ratio of the units derived from the radical-polymerizable acid anhydride in the polymer is 0.1 to 5% by weight, and the ratio of the units derived from the radical-polymerizable comonomer other than the radical-polymerizable acid anhydride is 10 to 50% by weight. % Or less of an ethylene-based copolymer, (b) a polyhydric alcohol compound having two or more hydroxyl groups in the molecule, (c) a reaction accelerator, and (d) a tackifier having a softening point of 80 to 200 ° C. The molar ratio of the unit of the hydroxyl group in the polyhydric alcohol compound as the component (b) to the unit derived from the radically polymerizable acid anhydride in the ethylene copolymer as the component (a) is 0.0
1 to 10, and the reaction accelerator as the component (c) is in the range of 0.001 to 20 parts by weight with respect to 100 parts by weight of the ethylene-based copolymer as the component (a), and the component The tackifier (d) is a layer formed of the heat-sensitive adhesive composition in an amount of 1 to 80 parts by weight with respect to 100 parts by weight of the ethylene copolymer as the component (a), and the intermediate layer has a melting point of 10
A multi-layer heat-sensitive adhesive film having a three-layer structure which is a polyolefin resin at 0 ° C or higher and having good air barrier performance, low-temperature adhesiveness, and heat-resistant creep property, and bonding a skin material and a substrate material using this multi-layer heat-sensitive adhesive film Disclosed multi-layered structures.

The present invention will be specifically described below. The present invention basically provides a heat-sensitive adhesive composition in which both outer layers have a specific resin composition, and a two-kind three-layer film in which the intermediate layer is a polyolefin resin having a melting point of 100 ° C. or higher. However, in principle, both outer layers do not have to have the same resin composition, and a three-layer, three-layer multilayer film is also included in the scope of the present invention. Similarly, a multilayer film having a structure of four or more layers can be used as long as it does not depart from the concept of the present invention.

Both outer layers of the multilayer heat-sensitive adhesive film of the present invention are heat-sensitive adhesive compositions having a specific resin composition capable of heat-sensitive adhesion to a skin material and a substrate material, and (a) ethylene and radical-polymerizable An ethylene-based copolymer composed of a radical-polymerizable comonomer other than an acid anhydride and a radical-copolymerizable acid anhydride, wherein the proportion of units derived from the radical-based acid anhydride in the ethylene-based copolymer is 0.1 to 0.1. 5% by weight, the proportion of units derived from radically polymerizable comonomers other than radically polymerizable acid anhydrides is 10 to 50% by weight or less, (b) two or more hydroxyl groups in the molecule Containing a polyhydric alcohol compound having the formula (c), a reaction accelerator (d) and a tackifier (d), which is a component of the component (b) which is derived from the radical-polymerizable acid anhydride in the component (a). Polyhydric alcohol The molar ratio of units of hydroxyl groups compounds in is in the range of 0.01 to 10, and (c) the reaction accelerator is a component is a component (a) ethylene copolymer 10
It is in the range of 0.001 to 20 parts by weight with respect to 0 parts by weight, and the tackifier which is the component (d) is 1 to 80 parts by weight with respect to 100 parts by weight of the ethylene copolymer which is the component (a). Which is a heat-sensitive adhesive composition.

The ethylene copolymer which is the component (a) relating to the present invention is a multi-component copolymer comprising ethylene, a radical-polymerizable acid anhydride and a radical-polymerizable comonomer other than the radical-polymerizable acid anhydride. . Here, the radical-polymerizable acid anhydride is a compound having at least one radical-polymerizable unsaturated bond and at least one acid anhydride group in the molecule, and capable of introducing an acid anhydride group into the molecule by polymerization. Means The acid anhydride group is preferably cyclic. Examples of such a compound include maleic anhydride, itaconic anhydride, citraconic anhydride, endic acid anhydride, dodecenyl succinic anhydride, 1-butene-3,4-dicarboxylic acid anhydride, and a carbon number of at most 18 And alkadienyl succinic anhydride having a double bond at the terminal. These may be used alone or in combination of two or more kinds. Among these, maleic anhydride and itaconic anhydride are particularly preferable.

The ratio of the units derived from the radical-polymerizable acid anhydride in the ethylene copolymer which is the component (a) is 0.
It is necessary to be in the range of 1 to 5% by weight, preferably 0.5 to 4.5% by weight, and particularly preferably 1.0 to 3.5% by weight. If the proportion of the radical-polymerizable acid anhydride is less than 0.1% by weight, the adhesive performance is insufficient and good adhesive strength cannot be obtained, and sufficient crosslink density cannot be obtained, resulting in sufficient heat creep resistance. I can't get it. On the other hand, if it exceeds 5% by weight, there is almost no effect of improving the adhesive strength, and further, it becomes difficult to manufacture it commercially, which is not preferable.

There are various compounds as the radical-polymerizable comonomer other than the radical-polymerizable acid anhydride constituting the ethylene copolymer as the component (a), such as an ethylenically unsaturated ester compound and an ethylenically unsaturated ester compound. Examples thereof include saturated amide compounds, ethylenically unsaturated acid compounds, ethylenically unsaturated ether compounds, ethylenically unsaturated hydrocarbon compounds, and other compounds. When these are specifically described, examples of the ethylenically unsaturated ester compound include vinyl acetate, methyl (meth) acrylate, (meth)
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate,
Octyl (meth) acrylate, lauryl (meth) acrylate, benzyl (meth) acrylate, methyl fumarate,
Ethyl fumarate, propyl fumarate, butyl fumarate,
Dimethyl fumarate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, methyl maleate, ethyl maleate, propyl maleate, butyl maleate, dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, etc. To be Examples of the ethylenically unsaturated amide compound include (meth) acrylamide, N-methyl (meth) acrylamide, N
-Ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-octyl (meth) acrylamide, N, N-dimethyl (meth)
Examples thereof include acrylamide and N, N-diethyl (meth) acrylamide. Examples of the ethylenically unsaturated acid compound include (meth) acrylic acid, maleic acid and fumaric acid. Examples of the ethylenically unsaturated ether compound include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octadecyl vinyl ether, phenyl vinyl ether and the like. Examples of the ethylenically unsaturated hydrocarbon compound include styrene, α-methylstyrene,
Examples thereof include norbornene and butadiene. Examples of other compounds include (meth) acrylonitrile, acrolein, crotonaldehyde, trimethoxyvinylsilane, vinyl chloride, vinylidene chloride, N-vinylacetamide and the like.

Among these, methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate are mentioned as particularly preferable compounds. These monomers may be used alone or in combination of two or more. The ratio of units derived from a radical-polymerizable comonomer other than the radical-polymerizable acid anhydride constituting the ethylene copolymer as the component (a) is 10
To 50% by weight, preferably 10 to 40% by weight, more preferably 12 to 35% by weight. Here, the ratio of the radical-polymerizable comonomer is 1
When it is less than 0% by weight, the crystal melting point of the ethylene-based copolymer is not sufficiently lowered, and the low temperature adhesiveness cannot be sufficiently exhibited. On the other hand, if it exceeds 50% by weight, it becomes difficult to handle the resin and the heat resistance of the product deteriorates.

As the method for producing the above-mentioned component (a) ethylene copolymer, various methods such as radical polymerization and solution polymerization can be used, but generally, a high pressure method and a low density method are usually used. It is manufactured using polyethylene manufacturing equipment and its technology. The ethylene copolymer, which is the component (a), melts at a relatively low temperature and is rich in physicochemical interactions and reactivity with various substrates, so that the resin composition of the present invention has high adhesion. It plays a major role in exerting power.

The polyhydric alcohol compound having at least two hydroxyl groups in the molecule of the component (b) relating to the multilayer heat-sensitive adhesive film of the present invention has a function as a so-called crosslinking agent. Specific examples of such a polyhydric alcohol compound include glycols such as ethylene glycol, diethylene glycol, and triethylene glycol; 1,4 butanediol, 1,6 hexanediol, 1,8 octanediol, 1, Alcohol compounds such as 10-decanediol, trimethylolethane, trimethylolpropane and pentaerythritol;
Sugars such as albitol, sorbitol, sorbitan, xylose, alaminose, glucose, galactose, sorbose, fructose, palatinose, maltotriose, and malezitose; saponification products of ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyolefin oligomers having a plurality of hydroxyl groups. Polymers having a plurality of hydroxyl groups in the molecule, such as ethylene-hydroxyethyl (meth) acrylate copolymer.

The polyhydric alcohol compound is represented by the general formula (I) or (II) (R) _a C (CH ₂ OH) _b ‥‥‥‥‥‥‥‥‥ (I) (wherein R is Hydrogen, a linear or cyclic alkyl group having 1 to 12 carbon atoms or an aralkyl group, wherein a is 0 to 2
Represents an integer of 2, b represents an integer of 2 to 4, and a + b =
4 is selected. _{) HO-CH 2 CH (OH} ) CH 2 -. [CH 2 CH (OH) CH 2 -O] n -H (II) ( wherein, n is an integer of 0) multivalent represented by A polyoxyalkylene compound having a structure in which ethylene oxide or propylene oxide is added to an alcohol compound, and a general formula (III) R′—COOH ‥‥‥‥‥‥‥‥‥ (III) (wherein R'is 2 carbon atoms). To 25 chain or cyclic alkyl groups or aralkyl groups), and an intramolecular compound obtained by dehydration condensation of the polyglycerin represented by the general formula (2). Two
It is also possible to use a polyglycerin ester having at least one hydroxyl group.

Further, as the polyhydric alcohol compound, sorbitan or a sorbitan alkyl ester of a sorbitan derivative having two or more hydroxyl groups in the molecule and an organic carboxylic acid compound represented by the general formula (III) is used. You can Specific examples of these polyoxyalkylene compounds include 1,3-dihydroxypropane, 2,2-dimethyl-1,3-dihydroxypropane, trimethylolethane, 1,1,1-trimethylolpropane and 1 , 1,1-trimethylolhexane, 1,1,1-trimethyloldodecane, 2-cyclohexyl-2-methylol-1,3-dihydroxypropane, 2- (p-methylphenyl) -2-methylol-
Examples thereof include 1,3-dihydroxypropane, pentaerythritol, glycerin, diglycerin, hexaglycerin, octaglycerin, decaglycerin and the like, which are reacted with ethylene oxide or propylene oxide.

Specific examples of the above-mentioned polyglycerin ester include glycerin monostearate, glycerin monooleate, glycerin monolaurate, glycerin monocaprylate, glycerin monohexanoate and glycerin monophenethyl. Ester, glycerin monopropionate, diglycerin monostearate, diglycerin distearate, diglycerin monooleate, diglycerin monohexanoate, diglycerin dioctanoate, tetraglycerin monostearate, tetraglycerin tristearate Rate, tetraglycerin tetrastearate, tetraglycerin trihexanoate, tetraglycerin monophenethyl ester, hexaglycerin monostearate,
Hexaglycerin distearate, hexaglycerin pentastearate, hexaglycerin trioleate,
Hexaglycerin monolaurate, hexaglycerin pentalaurate, decaglycerin monostearate, decaglycerin octastearate, decaglycerin pentaoleate, decaglycerin dilaurate, pentadecaglycerin distearate, pentadecaglycerin decaoleate, octadeca Examples thereof include glycerin tetrastearate. Further, as the sorbitan alkyl ester, specifically, for example, sorbitan monostearate, sorbitan monooleate, sorbitan monolaurate, sorbitan monocaprylate, sorbitan monohexanoate, sorbitan monophenethyl ester, sorbitan monopropionate. , Sorbitan tristearate, sorbitan tetrastearate and the like.

Of these polyhydric alcohol compounds, polyoxyalkylene compounds and polyglycerin esters are preferably used as the polyhydric alcohol compound having two or more hydroxyl groups in the molecule of component (b).
These polyhydric alcohol compounds may be used alone or as a mixture of two or more kinds. The amount of the polyhydric alcohol component (b) used is the amount of the component (a)
The molar ratio of the hydroxyl group contained in the polyhydric alcohol compound to the unit derived from the unsaturated carboxylic acid anhydride contained in the ethylene copolymer is in the range of 0.01 to 10, more preferably 0.05. It is preferably in the range of -5.
If this molar ratio is less than 0.01, the heat resistance and strength of the resulting sheet will be insufficient and the molar ratio will be 10
If the amount is larger than the above value, the molding becomes extremely difficult depending on the processing temperature in some cases, which is not preferable.

The reaction accelerator, which is the component (c) in the multilayer heat-sensitive adhesive film of the present invention, is a compound which activates carbonyl contained in a unit derived from an unsaturated carboxylic acid anhydride contained in an ethylene copolymer. , A compound that promotes the reaction between a hydroxyl group and an acid anhydride. An example of such a reaction accelerator is a metal salt of an organic carboxylic acid.
Examples of the metal salt of organic carboxylic acid include 1 to 30 carbon atoms.
Carboxylic acids such as acetic acid, butyric acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and behenic acid, which are fatty acids of, and IA, IIA, IIB, IIIB of the periodic table Group metals (eg L
i, Na, K, Mg, Ca, Zn, Al, etc.). Specifically, lithium acetate, sodium acetate, magnesium acetate, aluminum acetate, potassium butyrate, calcium butyrate, zinc butyrate, sodium octanoate, calcium octanoate, potassium decanoate, magnesium decanoate, zinc decanoate, lithium laurate. ,
Sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate, potassium stearate, calcium stearate, zinc stearate, Examples thereof include sodium oleate and sodium behenate. Preferably, lithium laurate, sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate, potassium stearate. , Calcium stearate, zinc stearate, sodium oleate and the like are used.

Another example of the metal salt of an organic carboxylic acid is a resin having a metal salt structure of a carboxylic acid. Examples of such resins include metals of Group IA, Group IIA, Group IIB, and Group IIIB of ethylene and radically polymerizable unsaturated carboxylic acid (for example, Li, Na, K, Mg, Ca, Zn, Al, etc.).
Examples thereof include those having a structure in which a salt is copolymerized, or those having a structure in which ethylene and a metal salt of the radical-polymerizable carboxylic acid and another radical-polymerizable unsaturated carboxylic acid and / or a derivative thereof are multi-polymerized. To be Further, a metal salt of the radical-polymerizable unsaturated carboxylic acid (a free unsaturated carboxylic acid may be polymerized and neutralized later on a polyolefin resin such as polyethylene, polypropylene, or a free ethylene-propylene copolymer. ) Is graft-polymerized, or a polyolefin resin is co-grafted with a metal salt of the radical-polymerizable carboxylic acid and another radical-polymerizable unsaturated carboxylic acid and / or derivative thereof at the same time. Is mentioned. Examples of the radically polymerizable unsaturated carboxylic acid and its derivative used here include:
(Meth) acrylic acid, maleic acid, fumaric acid, monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monobutyl maleate, monobutyl fumarate, methyl (meth) acrylate, dimethyl maleate, dimethyl fumarate , Diethyl maleate, diethyl fumarate, dibutyl maleate, dibutyl fumarate and the like.

Another example of the reaction accelerator is a tertiary amine compound. Specific examples of the tertiary amine compound used here include trimethylamine, triethylamine, triisopropylamine, trihexylamine, trioctylamine, trioctadecylamine,
Dimethylethylamine, methyldioctylamine, dimethyloctylamine, diethylcyclohexylamine,
N, N-diethyl-4-methylcyclohexylamine,
Diethylcyclododecylamine, N, N-diethyl-1
-Adamantanamine, 1-methylpyrrolidine, 1-ethylpyrrolidine, 1-ethylpiperidine, quinucudiline,
Triphenylamine, N, N-dimethylaniline, N,
N-diethylaniline, N, N-dimethyl-m-phenetiazine, 4-t-butyl-N, N-dimethylaniline and the like can be mentioned. Another example of the reaction accelerator may be a quaternary ammonium salt. Specific examples of the quaternary ammonium salt used here include tetramethylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetramethylammonium bromide, tetraethylammonium bromide, tetraethylammonium iodide, methyltri-n-butylammonium chloride, Examples thereof include tetrabutylammonium bromide, tetrahexylammonium bromide, tetraheptylammonium bromide, phenyltrimethylammonium bromide and benzyltriethylammonium chloride.

Further, as another example of the reaction accelerator, IIA
Examples thereof include hydroxides of group IIIB, group IIIB, and group IIIB metals.
Specific examples include calcium hydroxide, magnesium hydroxide, aluminum hydroxide and the like. Also II
Examples thereof include halides of Group A and Group IIB metals. Specific examples thereof include calcium chloride, calcium bromide, magnesium chloride and the like. Furthermore, oxo acid and I
Salts of metals of Group A, Group IIA, Group IIB and Group IIIB can be mentioned as other examples of the reaction accelerator according to the present invention. Specific examples thereof include sodium nitrate, calcium nitrate,
Zinc nitrate, magnesium nitrate, aluminum nitrate, sodium phosphate, calcium phosphate, sodium carbonate, calcium carbonate, magnesium carbonate, sodium sulfate, zinc sulfate, magnesium sulfate, aluminum sulfate, sodium chlorate, potassium chlorate, sodium iodate, etc. To be Furthermore, LiBF ₄ , NaBF ₄ , KBF ₄ , NaPF ₆ , KPF ₆ ,
NaPCl ₆ , KPCl ₆ , NaFeCl ₄ , NaSnCl ₄ , NaSbF ₆ , KSbF
Alkali metal salts of Lewis acids such as ₆ , NaAsF ₆ and KAsCl ₆ can also be mentioned as other examples of the reaction accelerator.

Among the reaction accelerators exemplified above, metal salts of organic carboxylic acids are preferably used. Further, the above-exemplified reaction accelerators may be used in combination of two or more kinds at the same time, if necessary. The amount of the reaction accelerator used here is 0. 0 based on 100 parts by weight of the ethylene copolymer.
The amount is 001 parts by weight or more and 20 parts by weight or less, and more preferably 0.01 parts by weight or more and 15 parts by weight. If this amount is less than 0.001 part by weight, the reaction becomes too slow and it becomes difficult to effectively introduce the crosslinked structure into the resin composition. Further, if this amount is more than 20 parts by weight, it is meaningless in terms of improving the reaction rate and is not economically preferable.

The tackifier as the component (d) relating to the multilayer heat-sensitive adhesive film of the present invention is a compound which imparts tackiness to an adherend and improves the adhesiveness at low temperature and low pressure. . Specific examples of such tackifiers include aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins,
Examples thereof include styrene resins. Specifically, as the aliphatic hydrocarbon resin, butene-
Homopolymers and copolymers of mono-olefins such as 1, isobutylene and the like having 4 or 5 carbon atoms and copolymers containing these mono-olefins as main components; butadiene, 1,3-
Examples thereof include homopolymers and copolymers of diolefins having a carbon number of 4 or 5, such as pentadiene, and copolymers containing these diolefins as a main component. As the alicyclic hydrocarbon-based resin, a resin obtained by cyclizing and dimerizing a diene component in a C _{4 to} C ₅ fraction and then polymerizing it, a resin obtained by hydrogenating an aromatic hydrocarbon-based resin described below in a nucleus Etc. Aromatic hydrocarbon resins include styrene, vinyltoluene,
Homopolymers and copolymers of vinyl aromatic hydrocarbons having 8 to 9 carbon atoms such as indene and α-methylstyrene (vinyltoluene-methylstyrene etc.) and copolymers containing these vinyl aromatic hydrocarbons as main components A polymer (styrene-olefin copolymer etc.) etc. are mentioned. Examples of the polyterpene resin include α-pinene polymer, β-pinene polymer, dipentene polymer, terpene-phenol polymer, α-pinene-phenol copolymer and the like. Examples of the rosins include rosin, polymerized rosin, hydrogenated rosin, rosin glycerin ester, and hydrogenated or polymerized products thereof. Of these, terpene phenol resin and hydrogenated petroleum resin are preferable. These are not only used alone,
It is possible to use two or more types together.

The softening point of the tackifier as the component (d) (the softening point as used herein means that measured by the ring and ball method).
Is preferably from 80 to 200 ° C. Especially 120-18
0 ° C is preferred. If the softening point of the tackifier is less than 80 ° C, the heat resistance of the multilayer heat-sensitive adhesive film becomes insufficient, and 2
If the temperature exceeds 00 ° C, the adhesiveness becomes insufficient, which is not preferable.
The amount of component (d) used is required to be 1 to 80 parts by weight, preferably 3 to 60 parts by weight, based on 100 parts by weight of the ethylene copolymer of component (a). If this amount is less than 1 part by weight, it is meaningless to add it substantially and the effect of improving the adhesive performance is lost, which is not preferable.
Further, if it exceeds 80 parts by weight, the heat resistance decreases and
It is not preferable because the multi-layer heat-sensitive adhesive film is too sticky and difficult to handle.

To form the multilayer heat-sensitive adhesive film according to the present invention, a heat-sensitive adhesive composition comprising component (a), component (b), component (c) and component (d) is added as component (e). A polyolefin resin can be added and used. Specific examples of the polyolefin resin here include low density polyethylene, high density polyethylene, polypropylene, polyisoprene, polyisobutylene, polybutene, poly-3-methylbutene-1, poly-4-methylpentene-1, and polybutadiene. Homopolymers of unsaturated hydrocarbon monomers having 2 to 10 carbon atoms can be mentioned. In addition, a copolymer of two or more kinds of monomers selected from the monomers constituting these homopolymers and other olefins, or the monomers constituting the above homopolymers or other olefins Copolymers with other radically polymerizable monomers having no acid anhydride, for example, ethylene-propylene; styrene-butadiene copolymers, ethylene-propylene-diene terpolymers, butene-1, hexene-1, octene-1. , 4-
Linear low-density polyethylene using methylpentene-1 or the like as a comonomer, propylene-ethylene block copolymer, ethylene-propylene random copolymer, copolymer of ethylene and unsaturated carboxylic acid or its derivative (for example, Ethylene-vinyl acetate copolymer, ethylene-
(Meth) acrylic acid ester copolymer and the like). Furthermore, a mixture of each of the above resins can be used.

The polyolefin resin used here has the purpose of being a resin for diluting a heat-sensitive adhesive composition comprising the above-mentioned components (a), (b), (c) and (d). In applications where adhesive strength at a high temperature (80 ° C. or higher) is required after bonding, the crystalline melting point of 100 ° C. or higher (the melting point here is a device such as DSC, DTA, etc.) among the polyolefin resins exemplified above. (Which means the melting peak temperature as measured by the above) can play an auxiliary role in achieving that purpose. That is, by adding the polyolefin resin, it is possible to more efficiently exhibit the contradictory performance of having a low-temperature adhesive property and capable of maintaining the adhesive strength to some extent even after the bonding at a high temperature.

The amount of the polyolefin resin as the component (e) used is 5 to 80 parts by weight based on 100 parts by weight of the total resin composition comprising the components (a), (b), (c) and (d). It is a range of parts. The amount of polyolefin resin used is 8
If the amount exceeds 0 parts by weight, the amount contained in the heat-sensitive adhesive composition, which is capable of originally exhibiting adhesion with other substrates, becomes too small, and therefore the adhesiveness of the resulting multilayer heat-sensitive adhesive film is significantly lowered, which is preferable. Absent. When the amount is less than 5 parts by weight, it is meaningless to mix the polyolefin resin.

Further, the heat-sensitive adhesive composition according to the present invention contains various additives within a range not impairing the characteristics of the composition.
It is possible to use compounding agents and fillers. For example, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, a flame retardant, a lubricant, an antiblocking agent, a coloring agent, a foaming agent and the like may be added as necessary. Since the main component of the heat-sensitive adhesive constituting the multilayer heat-sensitive adhesive film of the present invention is a cross-linked product of an ethylene-based copolymer to the last, the composition is determined in the range of not impairing the performance of the present multilayer heat-sensitive adhesive film. There is a need.

In order to produce the heat-sensitive adhesive composition of the present invention, the component (a), the component (b), the component (c), the component (d) and the component (e) or the additives used as necessary. The agent may be mixed by various means. As a mixing method, a generally known mixing method of various resins can be used. For example, dry blending may be performed using a mixer such as a Henschel mixer and a tumbler, and melt kneading may be performed using a mixer such as a Banbury mixer, a static mixer, a pressure kneader, an extruder and a roll mill. At this time, a uniform composition can be obtained by previously dry blending and melt-kneading the resulting mixture. In addition, it is also possible to mix (dry blend) each component in the form of pellets or powder using the step of molding the multilayer heat-sensitive adhesive film according to the present invention using an extruder or an injection molding machine, and perform melt mixing. it can.

The multilayer heat-sensitive adhesive film according to the present invention is
The heat-sensitive adhesive composition described above is used as both outer layers and has a melting point of 1
A polyolefin resin having a temperature of 00 ° C. or higher serves as an intermediate layer. The polyolefin resin referred to here is a combination of high-density polyethylene, low-density polyethylene, polypropylene, polyisoprene, polybutene, poly-3-butylbutene-1, poly-4-methylpentene-1, polybutadiene, and the constituent units of the resin. It means a polymer, that is, a linear low-density polyethylene, a propylene-ethylene copolymer (random or block), etc., and a mixture thereof. Among these, the polyolefin resin that can be used in the present invention needs to have a melting point of 100 ° C or higher, and preferably has a melting point of 105 ° C or higher and 170 ° C or lower. The melting point as used herein means the melting main peak temperature measured by a device such as DSC or DTA. The melting point is limited so that no perforation will occur in the multilayer film during heat-sensitive adhesion, and if the melting point is less than 100 ° C., there is a risk that perforation will occur during heat-sensitive adhesion and the air barrier property will deteriorate. The reason for limiting the use to the polyolefin resin is that the interlayer adhesiveness with the above-mentioned crosslinked resin composition and economical efficiency are taken into consideration.

In the production of the multilayer film, there are 2 types 3
A desired multilayer film can be obtained in one step by using a T-die film molding machine or an inflation film molding machine using a multi-layer die of two layers.
It is also possible to laminate the seed films by a method such as hot roll laminating or dry laminating to form a multilayer film. Further, a method of extrusion-laminating the composition for outer layer on the two-kind two-layer film or extrusion-sand laminating a polyolefin resin between the films for outer layer is also possible. The individual layers and the total thickness of the multilayer film cannot be unequivocally limited because they can vary greatly depending on the intended use and adhesion conditions of the final multilayer structure. As a general guideline, the thickness of each layer is 10 to 50 μm, and the total thickness is 30 to 50 μm.
Although it is 150 μm, of course, there are applications that can be used outside this range. A too thick film is not preferable from the viewpoint of easy handling and economical efficiency of the film, and if it is too thin, the air barrier property is deteriorated. Therefore, it is necessary to consider an appropriate balance depending on the situation.

Next, a multilayer structure using the multilayer heat-sensitive adhesive film of the present invention will be described. The multi-layer structure according to the present invention is a multi-layer laminate in which a skin material and a substrate material are laminated using the multi-layer heat-sensitive adhesive film, and is mainly suitable for use as an automobile interior material. Specific examples of the skin material include polyester non-woven fabric, nylon non-woven fabric, various woven fabrics,
Brushed knit, various synthetic papers, fabrics, suede-like synthetic leather, vinyl chloride (polyvinyl chloride) leather, polyurethane leather, polypropylene thermoplastic elastomer or cushioning materials such as urethane foam, polyethylene foam, polypropylene foam etc. The thing etc. are mentioned. Specific examples of the substrate material include resin felt,
Resin wood, glass fiber reinforced phenolic resin plate, corrugated board, polypropylene honeycomb, polystyrene foam, glass fiber reinforced polypropylene plate, glass fiber reinforced AS resin plate, ABS resin plate, AS resin plate, or a non-woven fabric bonded to them To be Among these, the effect of the present invention is most effectively exerted when the skin material and the substrate material have air permeability and the adhesive film is required to have an air barrier property, and specifically, various skin materials are used. This is the case when resin felt, resin wood, cardboard, etc. are used as materials such as non-woven fabrics, various woven fabrics, various synthetic papers, and substrate materials.

In manufacturing the multilayer structure, various existing molding methods can be used. To give a general example, a method of sandwiching a multi-layer heat-resistant heat-sensitive adhesive film between a skin material and a substrate material and adhering it with a hot press using a mold, a multi-layer heat-resistant heat-sensitive adhesive film laminated on the skin material by hot roll laminating in advance. In addition, a method of adhering to a substrate material by vacuum forming may be mentioned. INDUSTRIAL APPLICABILITY The multilayer structure according to the present invention can be widely used as an interior material for automobiles and the like, has heat resistance and has creep resistance, and in particular, it is completely prevented from seeping out moisture to the outside of the skin. The performance is greatly improved compared to the product. The present invention will be specifically described below with reference to examples.

[0037]

Examples The following resins were used as the ethylene-based copolymer (a) component. Ethylene copolymer (A): ethylene-methyl acrylate-maleic anhydride terpolymer MFR (JIS-K
7210, Table 1, condition 4) 10 g / 10 min. , The content of units derived from methyl acrylate is 25% by weight,
The content of units derived from maleic anhydride is 1.6% by weight Ethylene copolymer (B): Ethylene-methyl methacrylate-itaconic anhydride terpolymer MFR (JIS-
K7120, Table 1, Condition 4) 20 g / 10 min. , The content of units derived from methyl methacrylate is 20% by weight,
The content of units derived from itaconic anhydride is 3.5% by weight Ethylene copolymer (C): Ethylene-methyl acrylate-maleic anhydride terpolymer MFR (JIS-K
7210, Table 1, condition 4) 8 g / 10 min. The content of units derived from methyl acrylate is 18% by weight, and the content of units derived from maleic anhydride is 2.5% by weight Ethylene copolymer (D): ethylene-butyl acrylate-maleic anhydride Terpolymer MFR (JIS-K
7210, Table 1, condition 4) 8 g / 10 min. The content of the units derived from butyl acrylate is 16% by weight, and the content of the units derived from maleic anhydride is 1.5% by weight. Ethylene copolymer (E): ethylene-vinyl acetate-maleic anhydride 3 Original copolymer MFR (JIS-K721
0, Table 1, condition 4) 15 g / 10 min. The content of the unit derived from vinyl acetate is 20% by weight, and the content of the unit derived from maleic anhydride is 2.5% by weight. Production examples of the heat-sensitive adhesive composition constituting the multilayer heat-sensitive adhesive film of the present invention , As described in the following reference example. Of course, the present invention is not limited to the following reference examples.

<Reference Example 1> An ethylene copolymer (A) was used as the ethylene copolymer (a) component, and a propylene oxide (4 mol) adduct of hexaglycerin was used as the polyhydric alcohol (b) component ( Hereinafter abbreviated as HG-40P)
2.0 parts by weight, 0.5 parts by weight of calcium stearate (hereinafter abbreviated as Ca-St) as a reaction accelerator (c) component, hydrogenated petroleum resin as a tackifier (d) component [Arakawa Chemical Co., Ltd.] Petroleum resin Alcon P125: softening point (ring and ball method 125 ° C.)] was added to 10 parts by weight and dry blended with a Henschel mixer, and then melt-kneaded at 170 ° C. using a 37 mmφ co-directional twin-screw extruder to obtain a heat-sensitive adhesive composition. Of pellets were obtained. The content of the formulation is shown in Table 1.

<Reference Example 2> An ethylene copolymer (A) was used as the ethylene copolymer (a) component, and a propylene oxide (3 mol) adduct of trimethylolpropane was used as the polyhydric alcohol (b) component. 1.5 parts by weight (hereinafter, abbreviated as TM-30P) and an ethylene-methacrylic acid copolymer (methacrylic acid content 2 as a component of the reaction accelerator (c)).
0% by weight of Na salt (1 of the unit derived from methacrylic acid)
5% by weight, and 5 parts by weight of a terpene phenol resin [Tamanor 803L manufactured by Arakawa Chemical Co., Ltd .: softening point (ring and ball method) 145 ° C.] as a tackifier (d) component was added. Melt kneading was carried out in the same manner as in 1 to obtain pellets of the heat-sensitive adhesive composition. The content of the formulation is shown in Table 1.

<Reference Example 3> Ethylene copolymer (C) was used as the ethylene copolymer (a) component, and 1.0 part by weight of decaglycerin dilaurate was used as the polyhydric alcohol (b) component to accelerate the reaction. Ethylene as the agent (c) component
5% of Na salt of methacrylic acid copolymer (same as in Reference Example 2)
5 parts by weight of a hydrogenated petroleum resin (same as in Reference Example 1) as a tackifier (d) component and melt-kneaded in the same manner as in Reference Example 1 to obtain pellets of the heat-sensitive adhesive composition. Obtained. The content of the formulation is shown in Table 1.

<Reference Example 4> A heat-sensitive adhesive composition was prepared by melt-kneading in the same manner as in Reference Example 1 except that the ethylene copolymer (D) was used as the ethylene copolymer (a) component. Pellets were obtained. The content of the formulation is shown in Table 1.

<Reference Example 5> A heat-sensitive adhesive composition was prepared by melt-kneading in the same manner as in Reference Example 2 except that the ethylene-based copolymer (E) was used as the ethylene-based copolymer (a) component. Pellets were obtained. The content of the formulation is shown in Table 1.

Reference Example 6 A heat-sensitive adhesive composition was prepared by melt-kneading in the same manner as in Reference Example 3 except that the ethylene copolymer (A) was used as the component of the ethylene copolymer (a). Pellets were obtained. The content of the formulation is shown in Table 1.

Reference Example 7 A heat-sensitive adhesive composition was prepared by melt-kneading in the same manner as in Reference Example 1 except that the ethylene-based copolymer (B) was used as the component of the ethylene-based copolymer (a). Pellets were obtained. The content of the formulation is shown in Table 1.

<Reference Example 8> A heat-sensitive adhesive composition was prepared by melt-kneading in the same manner as in Reference Example 2 except that the ethylene-based copolymer (C) was used as the ethylene-based copolymer (a) component. Pellets were obtained. The content of the formulation is shown in Table 1.

Reference Example 9 The ethylene copolymer (A) was used as the ethylene copolymer (a) component, and 2.0 parts by weight of HG-40P was used as the polyhydric alcohol (b) component.
0.5 parts by weight of Ca-St as the reaction accelerator (c) component, 10 parts by weight of hydrogenated petroleum resin Alcon P125 as the tackifier (d) component, and low density polyethylene [MFR] as the polyolefin resin (e) component. (JIS-K72
10, Table 1, condition 4): 10 g / 10 min, density (JIS
-K6760): 0.916 g / cc, crystal melting point: 10
5 ° C.] was added to 20 parts by weight and melt-kneaded in the same manner as in Reference Example 1 to obtain pellets of the heat-sensitive adhesive composition. The content of the formulation is shown in Table 1.

Reference Example 10 Ethylene Copolymer (a)
An ethylene copolymer (B) is used as a component, TM-30P as a polyhydric alcohol (b) component is 1.5 parts by weight, and an ethylene-methacrylic acid copolymer (methacrylic acid as a reaction accelerator (c) component is used. 5 parts by weight of Na salt having a content of 20% by weight (neutralizing 10 mol of a unit derived from methacrylic acid), 5 parts by weight of terpene phenol resin Tamanol 803L as a tackifier (d) component, polyolefin resin (e) ) Linear low-density polyethylene [(JI
20 parts by weight of S-K7210, Table 1, condition 4): 15 g / 10 minutes, melting point 120 ° C.] were added and melt-kneaded in the same manner as in Reference Example 1 to obtain pellets of the heat-sensitive adhesive composition.
The content of the formulation is shown in Table 1.

<Comparative Reference Example 1> An ethylene copolymer (A) was used as the ethylene copolymer (a) component,
The polyhydric alcohol (b) component, the reaction accelerator (c) component, the tackifier (d) component and the polyolefin resin (e) component were not used. The content of the formulation is shown in Table 1.

<Comparative Reference Example 2> An ethylene copolymer (A) was used as the ethylene copolymer (a) component,
Melt kneading was carried out in the same manner as in Reference Example 1 except that the reaction accelerator (c) component in Reference Example 1 was not used to obtain pellets. The content of the formulation is shown in Table 1.

Comparative Reference Example 3 An ethylene copolymer (D) was used as the ethylene copolymer (a) component,
Reaction accelerator (c) component and tackifier (d) in Reference Example 1
Melt kneading was carried out in the same manner as in Reference Example 1 except that the components and the polyolefin resin (e) component were not used to obtain pellets. The content of the formulation is shown in Table 1.

<Example A><ExampleA1> The adhesive resin composition produced in Reference Example 1 was used with a multilayer T-die film forming machine having a two-kind three-layer T-die to form both outer layers and a low density. Polyethylene [MF
R (JIS-K7210, Table 1, Condition 4): 10 g / 1
0 minutes, density (JIS-K6760): 0.916 g / c
c, crystal melting point: 105 ° C.] as an intermediate layer, a two-kind, three-layer multi-layer heat-sensitive adhesive film having a thickness of both outer layers of 20 μm, a thickness of the intermediate layer of 40 μm and a total thickness of 80 μm was produced. Molding temperature is 210 ℃ in the die, molding speed is 25m
Per minute. Table 2 shows the constitution of each layer.

<Example A2> The heat-sensitive adhesive composition obtained in Reference Example 2 was used as both outer layers, and linear low-density polyethylene [MFR (JIS-K7210, Table 1, condition 4): 15 g was used for the intermediate layer. / 10 min, melting point 120 ° C.] and in the same manner as in Example A1 to obtain a multi-layer, two-kind heat-sensitive adhesive film. The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 40 μm, and the total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

<Example A3> The heat-sensitive adhesive composition obtained in Reference Example 3 was used as both outer layers, and high density polyethylene [MFR (JIS-K7210, Table 1, Condition 4): 7 g / 10 minutes was used for the intermediate layer. , Melting point 132 ° C.] and in the same manner as in Example A1 to obtain a two-kind three-layer multilayer heat-sensitive adhesive film. The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 20 μm.
The total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Example A4> The heat-sensitive adhesive composition obtained in Reference Example 2 was used as both outer layers, and polypropylene [MFR (JIS-K7210, Table 1, condition 14)] was used for the intermediate layer:
7.5 g / 10 min, melting point 165 ° C.], Example A
In the same manner as in 1, a multilayer heat-sensitive adhesive film of 2 types and 3 layers was obtained. The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 20 μm.
m and the total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Example A5> The heat-sensitive adhesive composition obtained in Reference Example 4 was used as both outer layers, and propylene was used as the intermediate layer.
Ethylene random copolymer [MFR (JIS-K721
0, Table 1, condition 14): 10 g / 10 min, melting point 144
C.] was used in the same manner as in Example A1 to obtain a two-kind three-layer multilayer heat-sensitive adhesive film. The thickness of both outer layers is 20μ
m, the thickness of the intermediate layer is 20 μm, and the total thickness is 60 μm
And Table 2 shows the constitution of each obtained film.

<Example A6> The heat-sensitive adhesive composition obtained in Reference Example 5 was used as both outer layers, and Example A5 was used as the intermediate layer.
Using the same propylene-ethylene random copolymer resin as in Example 1 above, a multilayer heat-sensitive adhesive film of 2 types and 3 layers was obtained in the same manner as in Example A1. The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 40 μm, and the total thickness was 80 μm.
Table 2 shows the constitution of each obtained film.

<Example A7> The heat-sensitive adhesive composition obtained in Reference Example 6 was used as both outer layers, and Example A1 was used as the intermediate layer.
The same low density polyethylene resin as in Example A1 was used.
A two-kind three-layer multi-layer heat-sensitive adhesive film was obtained by the same method as described above. The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 20 μm.
m and the total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Example A8> The heat-sensitive adhesive composition obtained in Reference Example 7 was used as both outer layers, and Example A2 was used as the intermediate layer.
Using the same linear low-density polyethylene resin as in Example 1 and in the same manner as in Example A1, a two-kind three-layer multilayer heat-sensitive adhesive film was obtained. The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 4 μm.
The thickness was 0 μm and the total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

<Example A9> The heat-sensitive adhesive composition obtained in Reference Example 8 was used as both outer layers, and Example A3 was used as the intermediate layer.
The same high density polyethylene resin as in Example A1 was used.
A two-kind three-layer multi-layer heat-sensitive adhesive film was obtained by the same method as described above. The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 20 μm.
m and the total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Example A10> The heat-sensitive adhesive composition obtained in Reference Example 9 was used as both outer layers, and Example A was used as the intermediate layer.
The same propylene-ethylene random copolymer resin as in Example 5 was used, and in the same manner as in Example A1, a two-kind, three-layer multilayer heat-sensitive adhesive film was obtained. The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 40 μm, and the total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

<Example A11> Reference Example 10 as both outer layers
Using the heat-sensitive adhesive composition obtained in 1. and using the same low-density polyethylene resin as that in Example A1 for the intermediate layer, a two-kind, three-layer multilayer heat-sensitive adhesive film was obtained in the same manner as in Example A1. . The thickness of both outer layers is 20 μm, and the thickness of the intermediate layer is 40 μm.
The total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

Comparative Example A1 A single layer film was obtained by molding only the adhesive resin composition of Reference Example 1 using a T-die film molding machine. The thickness of the obtained film is 60 μm
And

Comparative Example A2 The heat-sensitive adhesive composition of Reference Example 9 was molded using a T-die film molding machine to obtain a single layer film. The thickness of the obtained film was 60 μm.

<Comparative Example A3> The ethylene-based copolymer component (a) was used as both outer layers, the propylene-ethylene random copolymer as used in Example A4 was used as the intermediate layer, and the same as in Example A1. By the method, a multilayer heat-sensitive adhesive film of 2 layers and 3 layers was obtained. The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 40 μm, and the total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

<Comparative Example A4> The heat-sensitive adhesive composition obtained in Reference Example 2 was used as both outer layers, and ethylene was used as the intermediate layer.
Vinyl acetate copolymer (vinyl acetate content 20%) [MF
R (JIS-K7210, Table 1, condition 4): 3 g / 10
Min., Melting point 85 ° C.] and in the same manner as in Example A1 to obtain a two-kind three-layer multilayer heat-sensitive adhesive film. The thickness of both outer layers was 20 μm, the thickness of the intermediate layer was 40 μm, and the total thickness was 80 μm. Table 2 shows the constitution of each obtained film.

<Comparative Example A5> Comparative Reference Example 2 as both outer layers
The same propylene-ethylene random copolymer resin as in Example A5 was used for the intermediate layer, and the same procedure as in Example A1 was used to obtain a multi-layer, two-kind, three-layer heat-sensitive adhesive film. It was The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 20 μm, and the total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Comparative Example A6> Comparative Reference Example 3 as both outer layers
The same propylene-ethylene random copolymer resin as in Example A5 was used for the intermediate layer, and the same procedure as in Example A1 was used to obtain a multi-layer, two-kind, three-layer heat-sensitive adhesive film. It was The thickness of each outer layer was 20 μm, the thickness of the intermediate layer was 20 μm, and the total thickness was 60 μm. Table 2 shows the constitution of each obtained film.

<Example B><ExampleB1> The multilayer heat-sensitive adhesive film obtained in Example A1 was used, a polyester non-woven fabric was used as a skin material, and a resin felt having a thickness of 2 mm was used as a substrate material. For 20 seconds under the condition of ² Kg / cm ² ) to obtain a multilayer structure. The resulting multilayer structure is 2
A test piece having a width of 5 mm was cut out, and a 180 degree peeling test (test temperature 23 ° C.) was performed. The adhesive interface did not peel off at all, and the substrate material was destroyed. For reference, its strength is 2.6K.
The width was g / 25 mm. Therefore, the obtained multilayer structure has sufficient adhesive strength as a laminate. Further, as a heat-resistant creep test, a 100 g load was hung at a 90 degree angle on a test piece that had been partially peeled, and the test piece was exposed to an atmosphere of 80 ° C. for 2 hours.
The peel length (mm) when left for 4 hours was measured and used as a guide for heat resistance. As a result, the peeling length was 0 mm, indicating good heat-resistant adhesiveness. Next, in order to confirm the air barrier property, 5 m of red ink was applied to the substrate material side of the obtained laminate.
Then, the red ink bleeding to the skin material side was visually observed. As a result, no bleeding of the red ink was observed and it was confirmed that the ink has a sufficient air barrier property.
The above results are shown in Table 3. From the above results, it can be seen that the multilayer structure according to the present invention is an extremely useful material in practical use.

<Examples B2 to B22> Using the multilayer heat-sensitive adhesive film, the skin and the substrate material shown in Table 2, a multilayer structure was obtained in the same manner as in Example B1, and the adhesiveness and heat resistance were obtained. And the air barrier property was evaluated. The results obtained are shown in Table 3.

<Comparative Example B1> Example B except that the monolayer film obtained in Comparative Example A1 was used as the heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier properties were evaluated in the same manner as in Example B1.
Adhesiveness was sufficiently strong, and the peel length was 0 mm in the heat-resistant creep test, indicating good heat-resistant adhesiveness, but the air barrier property was evaluated. As a result, the red ink oozes out to the skin material side. Was found, and it was found that the heat resistant pinhole property was insufficient. The results obtained are shown in Table 3.

<Comparative Example B2> Example B except that the monolayer film obtained in Comparative Example A2 was used as the heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier properties were evaluated in the same manner as in Example B1.
Adhesiveness was sufficiently strong, and the peel length was 0 mm in the heat-resistant creep test, indicating good heat-resistant adhesiveness, but the air barrier property was evaluated. As a result, the red ink oozes out to the skin material side. Was found, and it was found that the heat resistant pinhole property was insufficient. The results obtained are shown in Table 3.

<Comparative Example B3> Example B except that the film obtained in Comparative Example A3 was used as the multilayer heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier properties were evaluated in the same manner as in Example B1.
Adhesiveness was obtained with sufficient strength, no red ink bleeding to the skin side was found in the evaluation of air barrier property, and it was found that it has sufficient air barrier property. In the test, the entire adhesive surface was peeled off within 24 hours, and it was found that the heat resistance was insufficient. The results obtained are shown in Table 3.

<Comparative Example B4> Example B except that the film obtained in Comparative Example A4 was used as the multilayer heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier property were evaluated in the same manner as in Example B1.
Adhesiveness was sufficient, but heat resistance and air barrier properties were insufficient. The results obtained are shown in Table 3.

<Comparative Example B5> Example B except that the film obtained in Comparative Example A5 was used as the multilayer heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier property were evaluated in the same manner as in Example B1.
Sufficient results were obtained for the adhesiveness and air barrier property, but it was found in the heat-resistant creep test that the entire adhesive surface was peeled off within 24 hours, and the heat resistance was insufficient. The results obtained are shown in Table 3.

<Comparative Example B6> Example B except that the film obtained in Comparative Example A6 was used as the multilayer heat-sensitive adhesive film.
A multilayer structure was obtained in the same manner as in 1. The adhesiveness, heat resistance and air barrier property were evaluated in the same manner as in Example B1.
Sufficient results were obtained for the adhesiveness and air barrier property, but it was found in the heat-resistant creep test that the entire adhesive surface was peeled off within 24 hours, and the heat resistance was insufficient. The results obtained are shown in Table 3.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

INDUSTRIAL APPLICABILITY The multilayer heat-sensitive adhesive film of the present invention is suitable as an adhesive layer when manufacturing a multilayer structure such as an automobile interior material, and is excellent in adhesive performance, air barrier property and heat resistance. Give the body.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-79817 (JP, A) JP-A-7-81008 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09J 7/02 B32B 7/12 B32B 27/32 C09J 123/08

Claims (7)

(57) [Claims] 1. Both outer layers are an ethylene-based copolymer comprising (a) ethylene and a radical-polymerizable acid anhydride and a radical-polymerizable comonomer other than the radical-copolymerizable acid anhydride. Ethylene in which the proportion of units derived from radical-polymerizable acid anhydride is 0.1 to 5% by weight, and the proportion of units derived from radical-polymerizable comonomer other than radical-polymerizable acid anhydride is 10 to 50% by weight. (B) a polyhydric alcohol compound having two or more hydroxyl groups in the molecule, (c) a reaction accelerator, (d) a tackifier having a softening point of 80 to 200 ° C. , and (a) The molar ratio of the unit of the hydroxyl group in the polyhydric alcohol compound as the component (b) is 0.0 with respect to the unit derived from the radical-polymerizable acid anhydride in the component ethylene-based copolymer.
1 to 10, and the reaction accelerator as the component (c) is in the range of 0.001 to 20 parts by weight with respect to 100 parts by weight of the ethylene-based copolymer as the component (a), and the component The tackifier (d) is a layer formed of the heat-sensitive adhesive composition in an amount of 1 to 80 parts by weight with respect to 100 parts by weight of the ethylene copolymer as the component (a), and the intermediate layer has a melting point of 10
A multilayer heat-sensitive adhesive film having a three-layer structure, which is a layer made of a polyolefin resin at 0 ° C or higher. 2. The polyhydric alcohol compound as the component (b) has the following general formula (I) (R ¹ ) _a C (CHOH) _b (I) [wherein R ¹ is hydrogen or 1 to 10 carbon atoms]. 12 chain or cyclic alkyl groups or aralkyl groups, a represents an integer of 0 to 2, b represents an integer of 2 to 4 and a +
It is selected to satisfy b = 4. ] Represented by polymethylolated, or in the following general formula _{(II) HO-CH 2 CH} (OH) CH 2 O [CH 2 CH (OH) CH 2 O] c -H (II) [wherein, c is 0 It is an integer of -10. ] The multilayer heat-sensitive adhesive film according to claim 1, which is a polyoxyalkylene compound having a structure in which ethylene oxide or propylene oxide is added to the polyglycerin represented by the formula [1]. 3. The multilayer heat-sensitive adhesive film according to claim 1, wherein the reaction accelerator as the component (c) is a metal salt of a polymer containing a carboxyl group or a metal salt of an organic carboxylic acid. Wherein component (d) tackifier terpene resins, multilayer heat-sensitive adhesive film according to any one of claims 1 to 3 is at least one resin selected from terpene phenol resin, hydrogenated petroleum resin . Relative wherein component (a) ~ consisting component (d) heat-sensitive adhesive composition 100 parts by weight, any polyolefin resin (e) according to claim 1-4 comprising 5-80 parts by weight The multilayer heat-sensitive adhesive film according to. 6. A multi-layer heat-sensitive adhesive film, wherein the thickness of the multilayer heat-sensitive adhesive film according to any one of claims 1 to 5 is 30μm or more 150μm or less. 7. A multilayer structure in which a skin material and a substrate material are bonded using the multilayer heat-sensitive adhesive film according to any one of claims 1 to 6.