JP2002114961A - Water-based adhesive composition and skinned molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based adhesive composition excellent in heat- resistant adhesion, and a skinned molded product having a skin adhered to the surface of a molded product with excellent heat-resistant adhesion. SOLUTION: The water-based adhesive composition comprises an emulsified polymer obtained by emulsion-polymerizing a monomer component (2) in the presence of a polymer component (1). The polymer component (1) is a vinyl polymer which comprises a macromonomer composed of a polymer, having a structure obtained by polymerizing at least one carboxylic group-containing monomer together with at least one hydrophobic monomer and bearing an ethylenically unsaturated bond at its end, and has an acid value of 1-8 meq/g and a glass transition temperature of 20-150 deg.C. The monomer component (2) is a polymerizable monomer forming a polymer having a glass transition temperature of -80 to -10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based adhesive composition and a molded article having a skin, and more particularly, to an aqueous adhesive composition having excellent heat-resistant adhesiveness and suitable for use in the adhesion of the skin in molded articles such as automobile interior materials. The present invention relates to an adhesive composition and a molded article having a skin in which an epidermis is adhered to the surface of a molded article using the aqueous adhesive composition.

[0002]

2. Description of the Related Art Solvent-based adhesives have been used in many cases for bonding a skin in a molded article having a skin used as an interior material of an automobile or the like. The solvent-based adhesive is composed of two components, a main component in which a chloroprene-based or polyester-based resin is dissolved in an organic solvent, and an isocyanate-based curing agent.

[0003] However, since the solvent-type adhesive contains an organic solvent, there is a problem in terms of working environment and disaster prevention.
For these reasons, in recent years, an aqueous adhesive that does not use an organic solvent has been strongly demanded.

[0004] As the aqueous adhesive, there is an aqueous emulsion obtained by emulsion polymerization, but there is a problem that the adhesiveness, particularly the heat-resistant adhesiveness, is inferior to the solvent-based adhesive. This is because the aqueous emulsion contains a low-molecular emulsifier.

[0005] To solve such a problem,
For example, an aqueous emulsion disclosed in JP-A-10-46117 is known. This aqueous emulsion is obtained by emulsion-polymerizing a monomer component in the presence of a specific polymer component. The polymer component is obtained by neutralizing a copolymer of a carboxyl group-containing monomer and a hydrophobic monomer (having a glass transition temperature of 20 ° C. or higher) with a base having a boiling point of 110 ° C. or lower.

[0006]

However, the above-mentioned aqueous emulsion has improved adhesiveness as compared with that produced by emulsion polymerization using a low-molecular emulsifier, but depending on the purpose of use, has poor heat-resistant adhesiveness. In some cases, it was insufficient, and the use was sometimes limited.

The present invention has been made by focusing on the problems existing in the prior art as described above. It is an object of the present invention to provide a water-based adhesive composition having excellent heat-resistant adhesiveness, and a molded article having a skin in which a skin is adhered to the surface of the molded article with excellent heat-resistant adhesiveness.

[0008]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, a monomer component (2) is emulsion-polymerized in the presence of the following polymer component (1). The gist of the present invention is to contain an emulsion polymer obtained by the above. Polymer component (1): From a macromonomer having an ethylenically unsaturated bond at a terminal of a polymer having a structure obtained by polymerizing at least one carboxyl group-containing monomer and at least one hydrophobic monomer. And the acid value is 1 to 8
A vinyl polymer having a meq / g and a glass transition temperature of 20 to 150 ° C. Monomer component (2): glass transition temperature -80 to -10 ° C
A polymerizable monomer forming a polymer of

According to a second aspect of the present invention, in the aqueous adhesive composition according to the first aspect, the polymer component (1) is obtained by radical polymerization at a reaction temperature of 180 to 350 ° C. Is the gist.

According to a third aspect of the present invention, there is provided a molded article having a skin constituted by joining a skin to the surface of the molded article, wherein the aqueous adhesive composition according to the first or second aspect is provided. Used at a temperature of 40 to 250 ° C. and a pressure of 0.01 to 50
The gist is that the skin is obtained by bonding the skin to the surface of the molded body in MPa.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail. The aqueous adhesive composition in the present embodiment contains an emulsion polymer obtained by emulsion-polymerizing the monomer component (2) in the presence of the polymer component (1) described below.

[Polymer Component (1)] First, the polymer component (1) will be described. The polymer component (1) is a macromonomer having an ethylenically unsaturated bond at a terminal of a polymer having a structure obtained by polymerizing at least one carboxyl group-containing monomer and at least one hydrophobic monomer. And a vinyl polymer having an acid value of 1 to 8 meq / g and a glass transition temperature of 20 to 150 ° C.

The acid value of the polymer component (1) is 1 to 8 meq /
g, preferably 2 to 5 meq / g. If the acid value is too small or too large, gelation or a large amount of grit occurs when the monomer component (2) is emulsion-polymerized in the presence of the polymer component (1), or the resulting aqueous solution In some cases, the adhesive composition may have low liquid stability. The term “liquid stability” refers to a property such that a solid substance does not precipitate, such as gelation, and components do not separate into a plurality of liquid phases.

In the present specification, the term "acid value" means an acid value per solid content of a resin, and means a theoretical acid value calculated by an ordinary method. When the resin is neutralized with a base, it means the acid value before neutralization. The unit of acid value "m
"eq / g" represents the number of milligram equivalents of acid in 1 g of resin solids.

The glass transition temperature (hereinafter, also referred to as Tg) of the polymer component (1) is from 20 to 150 ° C., and preferably from 4 to 150 ° C.
0-120 ° C. When the Tg is lower than 20 ° C., the resulting water-based adhesive composition has reduced heat resistance.

In the present specification, the "glass transition temperature" of a polymer refers to a value obtained from the following equation. Only Tg used in this calculation formula means absolute temperature (K), but Tg used in other parts of the specification means Celsius temperature (° C.).

1 / Tg = {W (a) / Tg (a)} + ｛W (b) /
Tg (b)｝ + where Tg is Tg (K) of the polymer, W (a) is the mass fraction of the structural unit derived from the monomer (a) in the polymer, and W (b)
Is the mass fraction of the structural unit derived from the monomer (b) in the polymer, Tg (a) is the glass transition temperature (K) of the homopolymer of the monomer (a), and Tg (b) is the monomer The glass transition temperature (K) of the homopolymer of (b) is shown.

The number average molecular weight of the polymer component (1) is 10
It is preferably from 00 to 50,000. When the number average molecular weight is less than 1,000, the water-based adhesive composition obtained tends to have insufficient water-resistant adhesiveness. On the other hand, when the number average molecular weight exceeds 50,000, the viscosity becomes high and the polymer component (1)
May be difficult to produce, and the solubility in water may be insufficient, and the liquid stability of the aqueous adhesive composition may decrease. To adjust the number average molecular weight,
Adjusting the polymerization temperature and the concentration of the polymerization initiator and appropriately adding a chain transfer agent to the polymerization system are effective means.

As an example of a method for obtaining such a macromonomer, a method of radically polymerizing a carboxyl group-containing monomer and a hydrophobic monomer at a reaction temperature of 180 to 350 ° C. (hereinafter, referred to as a high-temperature polymerization method). A method of adding a compound having an epoxy group and an ethylenically unsaturated bond to a copolymer of a hydroxyl group-containing monomer having a carboxyl group at the terminal and a hydrophobic monomer, and further adding an acid anhydride to the copolymer (hereinafter, referred to as an acid anhydride) , An addition reaction method).

A method based on an addition reaction is disclosed in JP-A-11-18 / 1999.
No. 1021 can be used. Hereinafter, a method by high-temperature polymerization will be described.

The polymer component (1) obtained by the high temperature polymerization method is a vinyl polymer comprising a macromonomer having an ethylenically unsaturated bond represented by the following general formula (A) at the terminal, (Neutralized macromonomer) is preferable.

[0022]

Embedded image Here, X in the formula (A) is a polar group such as a -COOR group, a phenyl group or a hydroxyalkyl group, R is a hydrogen atom or an alkyl group, M is a monomer unit, and n is a natural number representing the degree of polymerization. It is.

The above-mentioned macromonomer is produced by polymerizing at least one carboxyl group-containing monomer and at least one hydrophobic monomer. The carboxyl group-containing monomer is a monomer having an ethylenically unsaturated bond and a carboxyl group in the molecule. Specific examples thereof include acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, unsaturated monobasic acids such as acryloxypropionic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, and cyclohexanedicarboxylic acid. And unsaturated acids such as unsaturated dibasic acids, maleic anhydride and tetrahydrophthalic anhydride. Among them, acrylic acid is preferred because of its high copolymerizability with other various monomers. These carboxyl group-containing monomers are used alone or in combination of two or more.

The hydrophobic monomer is a monomer having a solubility in water at 20 ° C. of 2% by mass or less, and specific examples thereof include methyl methacrylate, ethyl (meth) acrylate, and (meth) acrylate. Propyl acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth)
Acrylates having an alkyl group of 2 to 22 carbon atoms such as 2-ethylhexyl acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, and perfluoroalkyl (meth) acrylate Or 1 to 22 methacrylates, vinyl propionate, styrene and the like. Among them, acrylates are preferable because a macromonomer having a high degree of polymerization is easily obtained. These hydrophobic monomers are used alone or in combination of two or more. still,
In this specification, (meth) acryl means acryl or methacryl, and (meth) acrylate means acrylate or methacrylate.

The mixing ratio of the carboxyl group-containing monomer and the hydrophobic monomer is preferably such that the carboxyl group-containing monomer accounts for 10 to 75 mol% of all the monomers, preferably 15 to 60 mol%.
The ratio which becomes mol% is more preferable. When the content of the carboxyl group-containing monomer is less than 10 mol% or more than 75 mol%, the performance of the obtained neutralized macromonomer as an emulsifier becomes insufficient.

The macromonomer may have a hydrophilic monomer as a constituent unit in addition to the carboxyl group-containing monomer and the hydrophobic monomer. Specific examples of the hydrophilic monomer include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylamide, and vinyl acetate. The amount of the hydrophilic monomer used is not particularly limited as long as the surface activity of the obtained macromonomer is not impaired, but is preferably 40 parts by mass or less with respect to 100 parts by mass of the macromonomer, and 30 parts by mass or less. Parts or less, more preferably
It is particularly preferred that the amount is 20 parts by mass or less.

The polymerization reaction between the carboxyl group-containing monomer and the hydrophobic monomer is preferably performed in the presence of a radical polymerization initiator. As the radical polymerization initiator, a known initiator can be used. Specific examples include hydrogen peroxide, alkyl hydroperoxide, dialkyl peroxide, perester, percarbonate, persulfuric acid, peracid, ketone peroxide, and azo initiator. Above all, in the range of 90 to 100 ° C, 1 to 1
A polymerization initiator having a half-life of 10 hours is preferred, but in some cases, a polymerization initiator having a half-life of 1 to 10 hours at a temperature lower than 90 ° C can be used.

Particularly preferred initiators include aliphatic azo compounds such as 1-t-amylazo-1-cyanocyclohexene, azo-bis-isobutyronitrile, 1-tert-butylazocyanocyclohexene, and t-butyl perocto. Peroxides and hydroperoxides such as ate, t-butyl perbenzoate, dicumyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, t-amyl hydroperoxide and cumene hydroperoxide; .

The amount of the radical polymerization initiator used is preferably from 0.05 to 10% by mass of all monomers. In the polymerization reaction between the carboxyl group-containing monomer and the hydrophobic monomer, a solvent may or may not be used. When a solvent is used, the solvent is preferably one that dissolves each of the above monomers and does not precipitate the polymer formed by the polymerization reaction. The solvent preferably has a high boiling point. Specifically, aromatic alcohols such as benzyl alcohol, isopropanol,
Aliphatic alcohols such as butanol, ethylene glycol monoalkyl ethers such as methyl cellosolve and butyl cellosolve, diethylene glycol monoalkyl ethers such as carbitol, ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, and diglycols such as diglycol methyl ether And alkyl ethers.

The reaction temperature when polymerizing the carboxyl group-containing monomer and the hydrophobic monomer is preferably from 180 to 350 ° C, more preferably from 270 to 320 ° C. If the temperature is lower than 180 ° C., the ratio of the polymer having no ethylenically unsaturated bond at the terminal increases, and the purity of the macromonomer decreases.

The reaction time is preferably within 60 minutes. This is because the polymerization reaction is substantially completed within 60 minutes.
The neutralized macromonomer is produced by neutralizing the macromonomer produced as described above with a base.

As the base used for neutralizing the macromonomer, ammonia or a low-boiling amine compound having a boiling point of 140 ° C. or lower is preferable. When ammonia or a low-boiling amine is used, when the adhesive layer is formed with the obtained aqueous adhesive composition, the ammonia or the low-boiling amine is easily evaporated by heat treatment when the adhesive layer is dried. An adhesive layer having excellent properties is obtained. Specific examples of the low-boiling amine include trimethylamine, diethylamine, triethylamine, methylethylamine, N-methylmorpholine, t-butanolamine, morpholine, and dimethylethanolamine.

The neutralization of the macromonomer with a base may be partial neutralization or complete neutralization. A preferred neutralization ratio is 50 to 100%. [Monomer Component (2)] Next, the monomer component (2) will be described.

The monomer component (2) is a polymerizable monomer that forms a polymer having a specific glass transition temperature. The glass transition temperature of the polymer obtained by polymerizing the monomer component (2) is −
The temperature is from 80 to -10C, preferably from -50 to -25C.
If the Tg is higher than -10 ° C, the resulting adhesive layer made of the aqueous adhesive composition has insufficient durability against stress and impact, so that its use should be avoided. In particular,
When Tg is −50 to −25 ° C., durability against stress and impact and heat resistant adhesiveness can be exhibited in a well-balanced manner.

The polymerizable monomer forming a polymer having a glass transition temperature of -80 to -10 ° C is an acrylic monomer,
Examples thereof include an ethylene-vinyl ester monomer and a conjugated diene monomer.

As the acrylic monomer, alkyl (meth) acrylate is mainly used, and other radical polymerizable monomers copolymerizable therewith (hereinafter referred to as “copolymerizable monomer”). ), It is preferable to use them together in a range of 40% by mass or less. If the use ratio of the copolymerizable monomer exceeds 40% by mass, the adhesive performance of the adhesive layer after heating during use tends to be insufficient.

As the alkyl (meth) acrylate, an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used. Specifically, methyl (meth) acrylate, (meth)
Ethyl acrylate, isopropyl (meth) acrylate,
N-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth)
Hexyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
N-octyl acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate and isononyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and the like. These alkyl (meth) acrylates may be used alone or in combination of two or more. In particular, it is preferable to use one or more of alkyl (meth) acrylates having 4 to 9 carbon atoms in the alkyl group as a main component.

Examples of the copolymerizable monomer include vinyl aromatic monomers such as styrene, α-methylstyrene and vinyltoluene; (meth) acrylic acid, crotonic acid,
Unsaturated carboxylic acids such as cinnamic acid, itaconic acid, fumaric acid and maleic acid; monoalkyl esters of unsaturated dicarboxylic acids such as monoethyl itaconate, monobutyl fumarate and monobutyl maleate; (meth) Hydroxyl-containing vinyl monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate; (meth) acrylonitrile, vinyl acetate, ( Meta)
Acrylamide, N-methylol acrylamide, glycidyl methacrylate, vinyl acetate, vinyl chloride, vinylidene chloride and the like can be mentioned. These copolymerizable monomers are
They are used alone or in combination of two or more.

Examples of the ethylene-vinyl ester monomer include a combination of ethylene with vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl laurate, vinyl versatate, and the like.

Examples of the conjugated diene monomer include butadiene, isoprene, chloroprene, and isobutylene. [Emulsion polymer] Next, the emulsion polymer contained in the aqueous adhesive composition will be described.

The emulsion polymer is obtained by emulsion-polymerizing the monomer component (2) in the presence of the above-mentioned polymer component (1). The amount of the polymer component (1) used is preferably 0.5 to 40 parts by mass, more preferably 5 to 30 parts by mass, per 100 parts by mass of the monomer component (2). If the amount is less than 0.5 parts by mass, the emulsion polymer may have poor liquid stability, and the water-based adhesive composition may have low heat resistance. Conversely, if it exceeds 40 parts by mass, the adhesiveness of the aqueous adhesive composition tends to decrease. In particular, when the amount of the polymer component (1) used is 5 to 30 parts by mass,
An aqueous adhesive composition having extremely excellent emulsion stability and excellent heat resistance can be obtained.

The emulsion polymerization of the monomer component (2) is preferably performed in the presence of a polymerization initiator. As the polymerization initiator, a polymerization initiator generally used for emulsion polymerization can be used. Specific examples include organic peroxides, inorganic peroxides, and azo compounds. The use amount of the polymerization initiator is preferably from 0.1 to 5% by mass of all the monomers.

The reaction temperature for emulsion polymerization of the monomer component (2) is preferably from 20 to 95 ° C, more preferably from 40 to 90 ° C. The reaction time is preferably 1 to 10 hours.

The monomer component (2) is used to prevent the system from becoming unstable when the polymer component (1) is added.
It is preferable to neutralize the polymer component (1) with a base or the like used for neutralization and to keep the pH close to the pH of the polymer component (1).

[Molded Body Having Skin] Next, a molded body having a skin in which the skin is adhered to the surface of the molded body using the aqueous adhesive composition will be described.

The molded body may be made of any material such as a wood material, a plastic material, a metal material, and an inorganic material. Examples of the wood material include a particle board (a particle board), a plywood, a laminated wood, a fiber board (a fiber board), and the like. Examples of the plastics material include polypropylene, polyethylene, polyvinyl chloride, ABS, polystyrene, polyester, polyurethane, acrylic resin, polycarbonate and the like. Examples of the inorganic material include gypsum, concrete, and ceramics.

The molded body may be formed into a final shape by applying heat and pressure during bonding to the skin, even if the molded body is formed into a final shape before the skin is bonded. There may be.

Examples of the skin include the plastic materials exemplified in the description of the molded article and materials such as foams, nonwoven fabrics and metal foils. Of these, foams such as polyethylene, polypropylene, and polyurethane are
The appearance, touch, durability and the like are particularly preferable because the skin becomes particularly good. These foams are porous and generally have poor adhesion, but can be effectively adhered according to the aqueous adhesive composition of the present embodiment.

The thickness of the skin is not particularly limited, but is preferably 10 μm to 50 mm, more preferably 50 μm to 2 mm.
0 mm. When the skin is adhered to the surface of the molded body, first, the aqueous adhesive composition is applied to one or both surfaces of the molded body and the skin to form an adhesive layer. Subsequently, the skin is superimposed on the surface of the molded body so that the adhesive layer is interposed, and in this state, the skin is adhered to the surface of the molded body by applying a predetermined pressure at a predetermined temperature.

The thickness of the adhesive layer can be appropriately adjusted depending on the application and the like, but is preferably from 10 μm to 1 mm.
About 20 μm to 200 μm, more preferably about 40 μm to 100 μm. By setting the adhesive layer to such a thickness, the adhesive strength between the molded body and the skin becomes larger.

The method of applying the aqueous adhesive composition is not particularly limited, and may be any method such as roll coater application, spray application, cast application, doctor blade application, brush application, and the like.

The adhesive layer is preferably dried after the application since the initial strength can be stably obtained. The drying method is not particularly limited, but a method using hot air or infrared rays is preferable. The drying temperature is preferably from room temperature to 150 ° C.
More preferably, it is 40 ° C to 120 ° C. When the drying temperature is low, it takes a long time to dry, which is not preferable from the viewpoint of work efficiency. When the drying temperature is high, the skin and the molded body may be deteriorated by heating. In particular, when the adhesive layer is formed and then dried at a temperature adjusted so as not to exhibit adhesiveness, a non-adhesive adhesive layer (hereinafter, referred to as a pre-coated adhesive layer) can be obtained. . The drying temperature in this case is preferably from room temperature to 100.
° C, more preferably 30 ° C to 80 ° C, still more preferably 40 ° C to 70 ° C.

The temperature at which the skin is adhered to the surface of the molded body is 40 to 250 ° C., preferably 70 to 180 ° C. If the temperature is lower than 40 ° C., the adhesive layer does not sufficiently soften, and does not follow the irregularities of the surface of the molded body or the skin that becomes the bonding surface.
In some cases, sufficient adhesive strength cannot be exhibited. 250 ° C
If it exceeds 300, the skin or the molded body may be altered or deformed. This temperature is preferably higher by at least 20 ° C. than the Tg of the polymer component (1), and more preferably higher by at least 50 ° C.

The pressure at which the skin is adhered to the surface of the molded product is 0.01 to 50 MPa, preferably 0.03 to 2 MPa.
a, more preferably 0.05 to 1 MPa. 0.0
When the pressure is less than 1 MPa, the adhesive layer cannot be brought into close contact with the bonding surface in a short time, so that the productivity is reduced. 50MPa
If it exceeds 300, the skin or the molded body may be altered or deformed.

The bonding of the skin is performed by a conventionally known pressure molding method, vacuum molding method, or the like. Specific examples include the method described in “Adhesion technology, vol. 13, No. 2, 52-57 (1993)”.

The peel strength of the skin adhered to the surface of the molded product was measured in accordance with JIS at 23 ° C. and 80 ° C.
1000 g when measured according to the 180 degree peeling method specified in Z 0237, that is, when the 180 degree peeling strength is measured at a pulling speed of 200 mm / min.
/ 25 mm or more, preferably 2000 g / 2
More preferably, it is 5 mm or more.

According to this embodiment described in detail above, an aqueous adhesive composition having excellent heat resistance can be obtained, and the following effects can be exhibited. Since the polymer component (1) is composed of a hydrophilic carboxyl group-containing monomer unit and a lipophilic hydrophobic monomer unit, the polymer component itself can function as an emulsifier (surfactant). . Accordingly, when the monomer component (2) is emulsion-polymerized in the presence of the polymer component (1), the amount of other emulsifiers such as protective colloids and surfactants used is smaller than in the case of ordinary emulsion polymerization. Can be suppressed. Alternatively, no other emulsifier can be used. Thereby, compared with the case where it is manufactured by a normal emulsion polymerization method,
Water resistance can be improved.

In the case of a conventional adhesive composed of two liquids, a main agent and a curing agent, there is a problem that the process control becomes complicated because storage cannot be performed in a state where the main agent and the curing agent are mixed.
However, since the aqueous adhesive composition of the present embodiment is a one-pack type, such a problem can be solved.

In the case of the conventional solvent-type adhesive, there is a problem in terms of working environment and disaster prevention because it contains an organic solvent. However, since the aqueous adhesive composition of the present embodiment does not contain an organic solvent, such a problem can be solved.

The above embodiment can be modified as follows. -After emulsion polymerization using an emulsifier such as a protective colloid or another surfactant, at least one of the polymer component (1) and the monomer component (2) may be added to perform two-stage polymerization.

The second emulsifier may be used in combination with the polymer component (1). Examples of the second emulsifier include a self-dispersible aqueous polymer or a water-soluble polymer disclosed in JP-A-10-46117. In this case, the total amount of the polymer component (1) and the second emulsifier is preferably 0.5 to 40 parts by mass per 100 parts by mass of the monomer component (2). The amount of the second emulsifier used is preferably 0.1 to 10 parts by mass per 1 part by mass of the polymer component (1).
In addition, the heat-resistant adhesiveness of the obtained aqueous adhesive composition improves as the ratio of the polymer component (1) increases.

Examples of other second emulsifiers include:
Anionic surfactants such as sodium alkyl benzene sulfonate, sodium polyoxyethylene alkyl sulfate, sodium dialkyl sulfosuccinate, and formalin condensate of naphthalene sulfonic acid; polyoxyethylene alkyl phenyl ether; polyethylene glycol fatty acid ester; sorbitan fatty acid ester; Nonionic surfactants, reactive surfactants such as sodium allyl alkyl sulfonate, alkyl allyl sulfosuccinate, polyoxyethylene alkyl allyl glycerin ether sulfate, alkyl propenyl phenol polyethylene oxide, protective colloids such as polyvinyl alcohol Is mentioned. The use amount of these is preferably 10% by mass or less of the polymer component (1).

Other components may be added to the aqueous adhesive composition depending on the use. Other components include adhesion improvers, anti-peeling agents, antifoaming agents, surfactants, fungicides, fragrances, neutralizers, thickeners, and leveling adjustments commonly used in general adhesives. Agent, deicing agent,
Foaming agents, antioxidants, ultraviolet absorbers, reinforcing agents, fillers, pigments, fluorescent brighteners, antistatic agents, anti-blocking agents, flame retardants, crosslinking agents, plasticizers, lubricants, organic solvents, coloring agents These are used alone or in combination of two or more.

As the adhesion improver, those having a Tg of 50 ° C. or higher or a softening point of 100 ° C. or higher are preferable from the viewpoint of heat resistance. When having Tg, Tg is 60 ° C to 150 ° C
Is more preferable, and what is 80 to 110 degreeC is still more preferable. Moreover, when it has a softening point, those having a softening point of 100 ° C to 200 ° C are more preferable, and
Those having a temperature of 20 ° C to 180 ° C are more preferred. If the Tg or softening point is too low, the heat-resistant adhesiveness of the aqueous adhesive composition may be poor. If the Tg or softening point is too high, the polymer component (1) and the monomer component (2) , The composition may be insufficient, and a uniform composition may not be obtained, storage stability may be impaired, or sufficient adhesiveness may not be obtained.

As the adhesion improver, a rosin-based resin, a terpene-phenol-based resin, a petroleum-based resin or the like satisfying the above conditions is preferably used. Examples of the rosin-based resin or its emulsified dispersion include trade names “Super Ester E-650” and “E-865” manufactured by Arakawa Chemical Industries, Ltd.
"E-873", "E-625", "E-730"
-55 "," Pencel D-125 "," D-13 "
5 "," D-160 "," KE-792 ", trade name" Hariester SK-130 "manufactured by Harima Chemicals, Inc.
D, MSR-4, K, DS-13
0, "AD-130", "KT-2J", "Harimac 130A", trade names "Pentalin FK125", "4741", "K", "2920", manufactured by Rika Hercules Co., Ltd., "Luisol 28-JA" and the like.

Examples of the terpene phenol-based resin or its emulsified dispersion include “Tamanol E-100” (trade name, manufactured by Arakawa Chemical Industries, Ltd.) and “YS Polystar T145” (trade name, manufactured by Yashara Chemical Co., Ltd.).
0, TH130, S145, Mighty Ace G150, Nanolet G150, G
145 "and the like.

Examples of the petroleum-based resin include “Nisseki Neopolymer 130” and “1
40 "," 150 "," 160 "," 170 "
S "," Same GS "," Nisseki Neoresin EP-140 ",
Examples include "Nisseki Uniresin # 730", a product name "FTR-6125" manufactured by Mitsui Petrochemical Co., Ltd., and a product name "Rigalite MBG273" manufactured by Rika Hercules Co., Ltd.

[0068]

Next, the embodiment will be described more specifically with reference to examples and comparative examples. In the following, the amounts used (parts and%) are based on mass.

Example 1 <Production of Polymer Component (1)> 70 parts of cyclohexyl acrylate (CHA), 30 parts of acrylic acid (AA), and 0.08 part of di-t-butyl peroxide were mixed. A monomer mixture was prepared. Under a deoxygenated atmosphere, the monomer mixture was heated at 254 ° C. for 12 minutes to perform polymerization. The polymerization was carried out using a polymerization apparatus capable of continuously pumping the monomer mixture into a stainless steel tube heated to 254 ° C. and controlling the residence time in the heated stainless steel tube to be 12 minutes.

After completion of the polymerization, the unreacted monomer is removed from the obtained reaction solution by a conventional method, and the macromonomer is neutralized by adding an equivalent of ammonia to the acid value of the product. (Tg = 37.1 ° C.).

The number average molecular weight of the neutralized macromonomer was determined to be 3020 by gel permeation chromatography (GPC). Moreover, the introduction rate of the ethylenically unsaturated bond at the end of neutralization macromonomer ¹ H
As a result of measurement by -NMR, 80% of the neutralized macromonomer had an ethylenically unsaturated bond at the terminal (introduction rate: 80%).

<Production of aqueous adhesive composition> Next, 75.5 parts of butyl acrylate (BA), 22.5 parts of methyl methacrylate (MMA) and 2 parts of 2-hydroxyethyl methacrylate (HEMA) were added. By mixing, a monomer mixture (Tg of the corresponding copolymer = -29.3 ° C.) was prepared. In a flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube, 80 parts of deionized water and 60 parts of the above-mentioned neutralized macromonomer (solid content: 30 parts) were charged, and charged under a nitrogen atmosphere.
After the temperature was raised to 10 ° C., 10 parts of a 10% aqueous solution of sodium sulfite and 80 parts of the above monomer mixture were added dropwise over 3 hours.
After maintaining the same temperature for 2 hours from the end of the dropwise addition, the reaction system was cooled to terminate the polymerization, and neutralized with aqueous ammonia to adjust the pH to 7 to 8, thereby obtaining an aqueous emulsion. The solids content of this aqueous emulsion was 50%.

An emulsion dispersion of a rosin-based resin (softening point: 160 ° C.) (trade name “Super Ester E-865”, 100 parts) was used for 100 parts of the monomer used in the production of the aqueous emulsion. Arakawa Chemical Industries, solid content 50
%), And an acrylic thickener (trade name "B-300" manufactured by Toagosei Co., Ltd.) and ammonia water were added thereto to add a Brookfield viscosity of 7000 mPa (25 ° C, 12 ° C).
rpm) and pH 7.5 to obtain the desired aqueous adhesive composition.

<Evaluation of water-based adhesive composition><1. Evaluation of Adhesiveness> After using a thermoplastic olefin foam sheet (thickness: 5 mm) to which a skin film is welded as a skin, and applying the aqueous adhesive composition obtained as described above to the back surface of the skin, 50 using a hot air dryer
By drying at 5 ° C. for 5 minutes, a precoat adhesive layer (about 45 μm in thickness) was formed.

The skin on which the precoat adhesive layer was formed was cut into a width of 25 mm and a length of 250 mm, and was superposed on the surface of a particle board (molded body). Then, at a temperature of 140 ° C., 0.049 MPa (0.5 kg / cm ² ) using a desktop test press (manufactured by Shinto Metal Industry Co., Ltd.).
Pressure was applied for 10 seconds to adhere the skin to the surface of the molded body to obtain a molded body having the skin.

A molded article having a skin was heated at a temperature of 23 ° C. and a humidity of 6
After standing for 24 hours in an atmosphere of 5%, the peel strength of the epidermis was measured according to the 180-degree peeling method specified in JIS Z 0237. That is, in an atmosphere of a temperature of 23 ° C. and a humidity of 65%, the 180-degree peeling strength of the adherend was measured at a tensile speed of 200 mm / min. Then, the adhesiveness of the aqueous adhesive composition was evaluated on a three-point scale based on the peel strength. Table 1 shows the results. still,
◎, ◎, and × in the table represent the following meanings.

A: Peel strength of 2000 g / 25 mm or more.
Particularly excellent in adhesiveness. ：: peel strength of 1000 g / 25 mm or more, 2000 g /
Less than 25mm. Has practically sufficient adhesiveness.

×: Peel strength less than 1000 g / 25 mm.
Lack of adhesiveness. <2. Evaluation of heat-resistant adhesive property> A molded article having a skin was formed in the same manner as in the evaluation of the adhesive property, and the molded article having the skin was allowed to stand for 24 hours in an atmosphere at a temperature of 23 ° C and a humidity of 65%. Thereafter, the molded body was horizontally fixed so that the skin side was on the lower side, and a 100 g weight was hung at the end of the skin. In this state, the film was left in an atmosphere of 90 ° C., and a distance (peeling distance) at which the skin was peeled off after 24 hours was measured. Then, the heat-resistant adhesiveness of the aqueous adhesive composition was evaluated on a three-point scale based on the peel distance. Table 1 shows the results. In addition, ◎,
○ and × represent the following meanings.

A: Peeling distance after 24 hours is 0 mm. Particularly excellent in heat resistance. ：: Peeling distance after 24 hours is within 10 mm. Has practically sufficient heat-resistant adhesiveness. ×: The peeling distance after 24 hours exceeds 10 mm, or all peeling is performed within 24 hours. Insufficient heat resistance.

(Example 2) In Example 1, the neutralized macromonomer was changed to one obtained by the following method. Otherwise, the operation was performed in the same manner as in Example 1. Table 1 shows the results of evaluating the adhesiveness and the heat-resistant adhesiveness.

A monomer mixture was prepared by mixing 45 parts of CHA, 20 parts of isobornyl acrylate (IBXA), 35 parts of AA, and 0.08 part of di-t-butyl peroxide. Thereafter, the same operation as in Example 1 was performed to produce a neutralized macromonomer. The number average molecular weight of this neutralized macromonomer was 3810, the introduction ratio of ethylenically unsaturated bonds was 84%, and the glass transition temperature was 56.7 ° C.

Example 3 In the production of the aqueous adhesive composition, 75 parts of BA and CHA22 were used as the monomer components (2).
Part, methacrylic acid (MAA) 1 part, and HEMA 2 parts monomer mixture (Tg of the corresponding copolymer = -3)
The same operation as in Example 1 was performed except that 9.1 ° C.) was used. Table 1 shows the results of evaluating the adhesiveness and the heat-resistant adhesiveness.

(Example 4) In Example 1, the aqueous emulsion was changed to that obtained by the following method. Otherwise, the operation was performed in the same manner as in Example 1. Table 1 shows the results of evaluating the adhesiveness and the heat-resistant adhesiveness.

BA 75 parts, CHA 22 parts, MAA 1 part,
And 2 parts of HEMA were mixed to prepare a monomer mixture (Tg of the corresponding copolymer = -39.1 ° C.). In a flask equipped with a stirrer, condenser, thermometer and nitrogen inlet tube,
80 parts of deionized water, 30 parts of a neutralized macromonomer (15 parts of solid content), and 30 parts of a non-reactive oligomer described below (15 parts of solid content) were charged and heated to 80 ° C. under a nitrogen atmosphere. 10 parts of a 10% aqueous solution of sodium and 80 parts of the above monomer mixture were added dropwise over 3 hours. Thereafter, the same operation as in Example 1 was performed to produce an aqueous emulsion.

<Non-reactive Oligomer> While blowing nitrogen into a flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen introducing tube, 40 parts of methyl ethyl ketone as a solvent were added.
And heated to 75 ° C. Subsequently, 45 parts of CHA,
AA 10 parts, mercaptopropionic acid (MPA) 2 parts as a chain transfer agent was charged into a flask as an initial raw material,
The polymerization was initiated by adding 0.5 parts of azo-bis-isobutyronitrile (AIBN) as a polymerization initiator. Next, 20 parts of methyl ethyl ketone and 1.0 part of AIBN were mixed and dissolved in 45 parts of a mixed liquid of 25 parts of CHA and 20 parts of AA, and the mixture was dropped into a flask over 4 hours as a continuous raw material to carry out polymerization. After completion of the dropwise addition, 0.5 part of AIBN and 40 parts of methyl ethyl ketone were added, and the temperature was maintained at the same temperature for 5 hours. Thereafter, the reaction system was cooled to terminate the polymerization, and a copolymer methyl ethyl ketone having a solid content of 50% was obtained. A solution was obtained.

Aqueous ammonia was gradually added to 200 parts of a methyl ethyl ketone solution of the obtained copolymer under stirring to neutralize the carboxyl groups in the copolymer to bring the pH of the reaction solution to about 7 to 8. did. After that, the temperature 5
The methyl ethyl ketone was removed under reduced pressure at 0 ° C. to obtain a non-reactive oligomer, that is, a low molecular weight polymer having no terminal ethylenically unsaturated bond. This non-reactive oligomer had a number average molecular weight of 3290 and a glass transition temperature of 37.1 ° C.

Example 5 In Example 1, the neutralized macromonomer was changed to that obtained by the following method. Otherwise, the operation was performed in the same manner as in Example 1. Table 1 shows the results of evaluating the adhesiveness and the heat-resistant adhesiveness.

MMA 55 parts, HEMA 25 parts, and AI
1 part of BN, 2 parts of MPA, and butyl acetate 10 as a solvent
Five parts were mixed to prepare a polymerization solution. Under a deoxygenated atmosphere,
The polymerization solution was heated at 90 ° C. for 10 hours to perform a first-stage reaction.

Subsequently, the solution obtained in the first-stage reaction was added to
One part of tetraammonium bromide as a catalyst and 0.1 part of hydroquinone monomethyl ether as a polymerization inhibitor
And 2.7 parts of glycidyl methacrylate, and 9
The mixture was further heated at 0 ° C. for 6 hours to carry out a second-stage reaction to obtain a solution of a hydroxy group-containing macromonomer (solid content: 50%).

Next, 20 parts of succinic anhydride and 80 parts of butyl acetate were added to 200 parts of the hydroxy group-containing macromonomer solution obtained in the second stage polymerization reaction, and the mixture was heated at 90 ° C. for 6 hours to form the third stage. The reaction was performed. In this reaction, the tetraammonium bromide used in the second-stage reaction was used as it was as a catalyst.

After completion of the polymerization, the macromonomer was neutralized by adding ammonia in an amount equivalent to the acid value of the product of the obtained reaction solution, and butyl acetate was removed under reduced pressure to remove the neutralized macromonomer. Obtained. The number average molecular weight of this neutralized macromonomer was 2620, and the glass transition temperature was 61.4 ° C.

Comparative Example 1 In Example 1, the neutralized macromonomer was changed to one obtained by the following method. Otherwise in the same manner as in Example 1, the polymerization was stopped because a large amount of aggregates was generated during the emulsion polymerization. This is considered to be because the emulsifying power of the neutralized macromonomer obtained by the following method is insufficient.

A polymerization liquid was prepared by mixing 30 parts of AA, 0.1 part of hydrogen peroxide and 70 parts of water, and using this polymerization liquid as a raw material, the same operation as in Example 1 was carried out. A sum macromonomer was prepared. The number average molecular weight of this neutralized macromonomer was 3,880, the introduction ratio of ethylenically unsaturated bonds was 72%, and the glass transition temperature was 130 ° C. The neutralized macromonomer has no hydrophobic monomer unit in the molecule.

Comparative Example 2 The procedure of Example 1 was changed to use the non-reactive oligomer used in Example 4 instead of the neutralized macromonomer. Otherwise, the operation was performed in the same manner as in Example 1. Table 1 shows the results of evaluating the adhesiveness and the heat-resistant adhesiveness.

[0095]

[Table 1] As shown in Table 1, in Examples 1 to 5, the adhesiveness and the heat-resistant adhesiveness were all good. 180 ~ 3
In the case of Examples 1 to 4 using the polymer component (1) obtained by radical polymerization at a temperature of 50 ° C, the adhesiveness and the heat-resistant adhesiveness were particularly excellent. On the other hand, Comparative Example 2 had good adhesiveness but low heat-resistant adhesiveness.

Next, the technical ideas that can be grasped from the above embodiment will be described below. The aqueous adhesive composition according to claim 1, wherein the polymer component (1) is a neutralized product obtained by neutralizing the macromonomer with a base. In such a configuration, the polymer component (1) can reliably exert an emulsifying power.

A step of preparing a monomer mixture containing a carboxyl group-containing monomer and a hydrophobic monomer, and a step of polymerizing the monomer mixture to form the following polymer component (1): And a step of subjecting the following monomer component (2) to emulsion polymerization in the presence of the polymer component (1). Polymer component (1): from a macromonomer having an ethylenically unsaturated bond at the end of a polymer having a structure obtained by polymerizing at least one carboxyl group-containing monomer and at least one hydrophobic monomer. And the acid value is 1 to 8
A vinyl polymer having a meq / g and a glass transition temperature of 20 to 150 ° C. Monomer component (2): glass transition temperature is -80 to -10C
A polymerizable monomer forming a polymer of

With this configuration, an aqueous adhesive composition having excellent heat resistance can be produced.

[0099]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the invention, excellent heat resistance can be exhibited.

According to the invention of claim 2, according to claim 1,
In addition to the effects of the invention described in (1), the heat resistance can be further improved. According to the third aspect of the present invention, the skin can be adhered to the surface of the molded body with excellent heat resistance.

 ──────────────────────────────────────────────────の Continuing on the front page F term (reference) 4F071 AA01B AA14B AA78A AA80A AA86A AH11 CB03 CD01 4F100 AK01B AK11A AK25 AK80 AL05A AS00C BA03 BA07 BA10A BA10C CB01A EH46 EH462 EJ42 EJ42A03 J03 EJ422A05 J03 EJ422A05 BA06 BA07 BA08 BA09 BA10 BA12 BA13 BA14 BA17 CB02 CB03 CB09 CC02 CD09 4J040 FA042 FA062 FA092 FA132 FA231 GA07 JA03 LA08 NA16

Claims (3)

[Claims] An aqueous adhesive composition comprising an emulsion polymer obtained by emulsion-polymerizing a monomer component (2) in the presence of the following polymer component (1). Polymer component (1): From a macromonomer having an ethylenically unsaturated bond at a terminal of a polymer having a structure obtained by polymerizing at least one carboxyl group-containing monomer and at least one hydrophobic monomer. And the acid value is 1 to 8
A vinyl polymer having a meq / g and a glass transition temperature of 20 to 150 ° C. Monomer component (2): glass transition temperature -80 to -10 ° C
A polymerizable monomer forming a polymer of 2. The polymer component (1) has a reaction temperature of 180.
The aqueous adhesive composition according to claim 1, which is obtained by radical polymerization at a temperature of from 350 to 350 ° C. 3. A molded article having a skin constituted by joining a skin to the surface of the molded article, wherein the aqueous adhesive composition according to claim 1 or 2 is used, and the temperature is 40 to 250.
A molded article having a skin, which is obtained by adhering a skin to the surface of the molded article at a temperature of 0C and a pressure of 0.01 to 50 MPa.