JP2000303047A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition for automobile interiors which composition is usable for bonding molded articles or skin materials made of a polyolefin such as a polypropylene or polyethylene. SOLUTION: This adhesive composition is such one that a styrene block copolymer which has been graft-polymerized with an acrylic monomer is blended with a silane coupling agent. Preferably, a weight ratio of the styrene block copolymer/the acrylic monomer is from 100/1 to 100/100, and that of the styrene block copolymer/the silane coupling agent is from 100/0.1 to 100/50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene,
The present invention relates to an automotive interior adhesive composition used for bonding a polyolefin molded article such as polyethylene or a polyolefin skin material.

[0002]

2. Description of the Related Art Currently, automobiles include, for example, instrument panels, doors, ceiling materials, rear trays, pillars, and the like.
Many interior materials are used. These interior materials are generally composed of a skin material and a molded product.In particular, when bonding a polyolefin molded product or a polyolefin skin material, the skin material is heated to the shape of the molded product using a chloroprene rubber-based adhesive. It is often bonded while forming.
The polyolefin skin material used here includes plastic sheets such as polyvinyl chloride and thermoplastic polyolefin, and surface materials such as tricot, cloth, and non-woven fabric, and polypropylene, polyethylene, polybutylene, and copolymers thereof. This is a material obtained by bonding or laminating a polyolefin-based foam produced mainly with a coalesced body by heat bonding or the like. Generally, the thickness of the surface layer material is about 0.3 mm to 1.5 mm, and the thickness of the polyolefin foam is about 1.5 mm to 3.0 mm. In addition, the polyolefin molded article used here includes injection molded articles and sheets of olefin-based plastics such as polypropylene resin, woody molded articles obtained by solidifying essential powder, synthetic fiber, vegetable fiber, and the like with a polyolefin resin by hot press molding. Means

[0003]

Adhesives used for automobile interior materials, in particular, chloroprene rubber-based adhesives are mainly used for bonding a polyolefin molded article to a polyolefin skin material. However, due to recent environmental problems, the use of materials containing halogen-based substances such as chlorine has been restricted. Styrene block copolymers are examples of base polymers for adhesives that can be bonded to polyolefin-based materials, but styrene blocks form domains and exert physical cohesive strength. It was unsuitable for automotive interior material applications where heat resistance is required.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that an adhesive characterized by blending a silane coupling agent with a styrene block copolymer obtained by graft polymerization of an acrylic monomer is used. Polymer / acrylic monomer weight ratio of 100/1 to 100
/ 100, and the weight ratio of styrene block copolymer / silane coupling agent is from 100 / 0.1 to 100 /
It has been found that by setting the ratio to 50, the heat resistance is improved.

The present invention relates to an adhesive characterized by blending a silane coupling agent with a styrene block copolymer obtained by graft polymerization of an acrylic monomer, wherein the weight ratio of styrene block copolymer / acryl monomer is 10%.
0/1 to 100/100, and the weight ratio of styrene block copolymer / silane coupling agent is 100/100.
The present invention relates to an automotive interior adhesive composition having a ratio of 0.1 to 100/50.

The styrene block copolymer used in the styrene block copolymer obtained by graft-polymerizing the acrylic monomer of the present invention includes styrene / isoprene / styrene block copolymer, styrene / butadiene / styrene block copolymer, and styrene / block copolymer. And ethylene / propylene / styrene block copolymers. The physical properties and properties of the styrene block copolymer are not particularly limited because they differ depending on the desired physical properties, but MI (melt index,
(200 ° C., 5 kg load) of 15 or less is preferable.

The acrylic monomer used in the styrene block copolymer obtained by graft-polymerizing the acrylic monomer of the present invention may be any one having an organic group capable of reacting with a silane coupling agent. Acid esters (eg, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, etc.), methacrylic acid and methacrylic acid esters (eg, glycidyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxypropyl methacrylate, etc.) And at least one selected from these groups can be used. In addition, in addition to the acrylic monomer, vinyl acetate, acrylonitrile, styrene, butadiene, acrylic acid and acrylate (eg, methyl acrylate, ethyl acrylate, etc.),
Acrylic monomers having no organic group capable of reacting with a silane coupling agent such as methacrylic acid and methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, etc.) can also be used in combination.

The silane coupling agent used in the present invention may be any one having a functional group reactive with an acrylic monomer graft-polymerized on a styrene block copolymer. For example, the graft-polymerized acrylic monomer may be glycidyl acrylate In the case of (a), isocyanate silane, amino silane and the like can be mentioned, and when the acrylic monomer is 2-hydroxyethyl acrylate, isocyanate silane and the like can be mentioned. Specifically, epoxy silane (for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane), aminosilane (for example, aminomethyltriethoxysilane, amino Methyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-ureidopropyltriethoxysilane, etc., mercaptosilane (for example, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane) Γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethylmethoxysilane, γ-mercaptopropylmethyldiethoxysilane Silane), isocyanate silane (e.g., γ-
Isocyanate propyl trimethoxy silane, γ-isocyanate propyl triethoxy silane, etc.), and at least one selected from these groups can be used. One or two or more combinations of these acrylic monomers and silane coupling agents can be selected and used according to various physical properties such as a desired curing speed.

The term "styrene block copolymer obtained by graft polymerization of an acrylic monomer" used herein refers to a graft polymerization of a styrene block copolymer using an acrylic monomer as an initiator. Examples of the initiator in the present invention include benzoyl peroxide, bis (2,4-dichlorobenzoyl) peroxide, di-t-butyl peroxide, 2,5-dimethylperoxyhexane, t-butyl perbenzoate, and t-butyl perbenzoate. Initiators composed of peroxides such as -butylperoxyisopropyl carbonate, persulfates such as ammonium sulfate, diazo compounds such as azobisisobutyronitrile and the like can be used. Usually, the initiator may be used in an amount of preferably 0.01 to 5 parts by weight based on 100 parts by weight of the styrene block copolymer before grafting. The reaction temperature and reaction time vary depending on the initiator used and the like.
The reaction may be performed at a temperature of 1 ° C. for 1 to 24 hours under a nitrogen atmosphere. The method of the graft reaction is not particularly limited. For example, the graft reaction can be performed in a solution of an organic solvent such as toluene.

The acrylic monomer to be grafted onto the styrene block copolymer has a weight ratio of styrene block copolymer / acryl monomer of from 100/1 to 100/100.
When the ratio is 100/1 or less, sufficient heat resistance cannot be obtained even if a large amount of the silane coupling agent is used. On the other hand, if the ratio is 100/100 or more, the crosslinking density becomes too high, and the stress relaxation property of the adhesive is deteriorated.

When a silane coupling agent is blended with a styrene block copolymer obtained by graft polymerization of an acrylic monomer, a functional group in the acrylic monomer and an organic functional group of the silane coupling agent undergo a chemical reaction. The reaction temperature and the reaction time vary depending on the reactivity of the functional group. For example, the reaction may be performed at a normal temperature to 110 ° C. for 1 to 24 hours under a nitrogen purge. If necessary, a catalyst for promoting the reaction can be added.

The weight ratio of the styrene block copolymer / silane coupling agent is preferably from 100 / 0.1 to 100/50, and if it is less than 100 / 0.1, sufficient heat resistance cannot be obtained. On the other hand, if the ratio is 100/50 or more, the crosslinking density becomes too high, and the stress relaxation property of the adhesive becomes poor, and the adhesiveness particularly at a low temperature decreases.

[0013] In addition, adhesion-imparting resins such as petroleum resins, terpene resins, cumarone-indene resins, rosin-based resins, epoxy resins, phenolic resins, acrylic resins,
One or more of butyral resin, olefin resin, chlorinated olefin resin, vinyl acetate resin, and modified resins thereof can be selected and blended in an appropriate amount. If necessary, stabilizers, coloring agents, catalysts, fillers and the like can be added.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive composition thus obtained is suitable for molding and bonding of automobile interior materials, especially for molding and bonding using a polyolefin material. Specifically, polyolefin molded products such as instrument panels, doors, ceiling materials, rear trays, and pillars (injection molded products and sheets of olefin-based plastics such as polypropylene resin, chips, wood chips, plant fibers, etc. are heated with polyolefin resin. Press-molded wooden molded products and wooden boards, etc., polyolefin skin materials (polyvinyl chloride, plastic sheets such as thermoplastic polyolefin, etc.), surface materials such as tricot, cloth, non-woven fabric etc., and polypropylene, polyethylene, It is particularly suitable for bonding polybutylene and a polyolefin-based foam produced by using these copolymers as a main component, or for bonding a material obtained by laminating by thermal fusion or the like.

In addition to this, the present adhesive may be used in addition to polyolefin molded products, such as ABS resin, polystyrene resin, and wood molded products obtained by hardening wood powder with a phenol resin by hot press molding. ,
It can also be used for bonding fibrous materials such as nonwoven fabrics and plastic sheets such as thermoplastic polyolefins.

[0016]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The results of these specific examples are shown in Table 1, but the present invention is not limited to these Examples. All parts are parts by weight.

Example 1 Styrene / butadiene / styrene block copolymer (Clayton D-1102JS;
100 parts of Shell Chemical Co., Ltd.) was heated and stirred at 80 ± 2 ° C. in a flask in which 300 parts of toluene had been replaced with nitrogen, and dissolved. Then, 5 parts of glycidyl methacrylate was used as an initiator, and 0.5 part of benzoyl peroxide was used as an initiator. The solution was added dropwise to perform graft polymerization. The flask was heated and stirred for 3 hours while maintaining the temperature at 80 ± 2 ° C., and the reaction was stopped by adding 0.5 part of hydroquinone as a terminator. After cooling to about 40 ° C., 200 parts of cyclohexane and petroleum resin (Alcon P1
00; Arakawa Chemical Co., Ltd.) to obtain an adhesive (I). To 100 parts by weight of the solid content of the adhesive (I), 5 parts of solid content of aminopropyltriethoxysilane (A-1100; manufactured by Nippon Unicar Co., Ltd.) was added and stirred and mixed for about 1 hour to obtain an adhesive (II).

(Example 2) In the same manner as in Example 1, 80 parts of a styrene / butadiene / styrene block copolymer (Clayton D-1102JS; manufactured by Shell Chemical Co., Ltd.) was mixed with styrene / ethylene / butylene / styrene block copolymer. Glycidyl methacrylate (10 parts) and a solution of benzoyl peroxide (0.5 part) as an initiator were added dropwise to 20 parts of the combined product (Clayton G1650; manufactured by Shell Chemical Co., Ltd.) to perform graft polymerization. After cooling to about 40 ° C, cyclohexane 200
Part, petroleum resin (Alcon P100; Arakawa Chemical Co., Ltd.) 80
And 20 parts of a petroleum resin (Neopolymer 150; manufactured by Nippon Petrochemical Co., Ltd.) were added and dissolved to obtain an adhesive (III). To 100 parts by weight of the solid content of the adhesive (III) was added 5 parts of aminopropyltriethoxysilane solid content, and the mixture was stirred and mixed for about 1 hour to obtain an adhesive (IV).

Example 3 In the same manner as in Example 1, 100 parts of a styrene / butadiene / styrene block copolymer (Clayton D-1102JS; manufactured by Shell Chemical Co., Ltd.) was used.
80 ± 2 in a flask with 300 parts toluene replaced with nitrogen
After heating and stirring at 0 ° C. and dissolving, 5 parts of glycidyl methacrylate was added as benzoyl peroxide 0.5 part as an initiator.
A part of the solution was dropped to perform graft polymerization. The flask was heated and stirred for 3 hours while maintaining the temperature at 80 ± 2 ° C., and the reaction was stopped by adding 0.5 part of hydroquinone as a terminator. After cooling to about 40 ° C., 200 parts of cyclohexane and 100 parts of a petroleum resin (Alcon P100; manufactured by Arakawa Chemical Co., Ltd.) were added to obtain an adhesive (V). Solid content of adhesive (V) 100
50 parts by weight of aminopropyltriethoxysilane solids
The mixture was stirred and mixed for about 1 hour to obtain an adhesive (VI).

[0020]

COMPARATIVE EXAMPLE (Comparative Example 1) The adhesive (VII) was obtained by replacing the solid content of aminopropyltriethoxysilane of the adhesive obtained in Example 1 with 0.1 part and stirring and mixing for about 1 hour.

(Comparative Example 2) The adhesive (VIII) was obtained by replacing the solid content of aminopropyltriethoxysilane of the adhesive obtained in Example 1 with 60 parts and stirring and mixing for about 1 hour.

Comparative Example 3 The amount of glycidyl methacrylate added to the adhesive obtained in Example 1 was changed to 0.1 part.
An adhesive (IX) was obtained.

Comparative Example 3 The amount of glycidyl methacrylate added to the adhesive obtained in Example 1 was replaced with 120 parts.
An adhesive (X) was obtained.

(Adhesion test) The obtained adhesive was applied onto a polypropylene molded product using a spray gun (application amount: 150 g / m ² -wet), and dried for 2 minutes in a drying oven set at 80 ° C. did. The polypropylene molded product left for 5 minutes in an atmosphere of 20 ° C. and an automotive interior skin material heated to a skin temperature of 110 ° C. (a surface material made of thermoplastic polyolefin and a laminate product of 25-fold foam mainly composed of polypropylene and having a thickness of 2 mm) ) Were adhered by vacuum molding. The bonded product is cured for one day in a 20 ° C./65% RH atmosphere, and is cured by a tensile tester in a 20 ° C. atmosphere.
A load of 200 g / 25 mm was applied vertically to one end of the skin material in an atmosphere of 80 ° peeling strength and 80 ° C. 24
A time creep test is performed to measure the peel length. Table 1 shows the test results.

[0025]

[Table 1]

[0026]

As described above, the present invention relates to an automotive interior adhesive composition used for bonding a polyolefin molded article such as polypropylene or polyethylene or a polyolefin skin material, and is currently mainly used. It has almost the same adhesiveness as chloroprene rubber adhesive.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J026 AA17 AA68 AA69 AC16 AC17 BA05 BA20 BA25 BA27 BA30 BA31 BA46 BB01 BB02 CA07 DB09 DB12 DB14 DB15 DB31 DB32 GA01 GA09 4J040 DL171 HD35 HD36 HD37 KA16 LA08 MA11 NA16

Claims (3)

[Claims] 1. An adhesive composition for automobile interiors having excellent heat resistance, characterized by blending a silane coupling agent with a styrene block copolymer obtained by graft polymerization of an acrylic monomer. 2. The adhesive composition according to claim 1, wherein the weight ratio of styrene block copolymer / acrylic monomer is from 100/1 to 100.
The adhesive composition according to claim 1, wherein the composition is / 100. 3. The adhesive according to claim 1, wherein the weight ratio of the styrene block copolymer / silane coupling agent in the adhesive composition is from 100 / 0.1 to 100/50. Composition.