JP2000303048A - Adhesive composition for soft polyvinyl chloride use adhesive product and adhered product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive compsn. and an adhesive product which are excellent in the balance of cohesive force and initial-stage adhesive force, the cohesive force hard to be degraded by the migration of a plasticizer, and have an excellent shelf life. SOLUTION: A crosslinked polymer obtd. by crosslinking an acrylic graft polymer is used as a main ingredient for an adhesive layer for soft polyvinyl chloride use. The acrylic graft polymer is prepd. by a manufacturing method comprising a polymerization step for copolymerizing a monomer mixture including an alkyl (meth)acrylate monomer in the presence of a high glass transition point polymer which has a glass transition point of 273 K or more and which is incompatible with a polymer from the monomer mixture, so that the monomer mixture is used in an amt. of 60-95 pts.wt. based on 100 pts.wt. of the total of the monomer mixture and the high glass transition point polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a pressure-sensitive adhesive, a pressure-sensitive adhesive product and a bonded product, particularly a composition for a pressure-sensitive adhesive applied to a flexible polyvinyl chloride molded product, a pressure-sensitive adhesive product and a bonded product. About.

[0002]

2. Description of the Related Art Soft PVC (ie, soft polyvinyl chloride or soft vinyl chloride resin) is used for dioctyl phthalate.
It contains low molecular weight plasticizers such as phthalic esters such as dibutyl phthalate, linear dibasic esters such as dioctyl adipate and dioctyl azelate, and phosphoric esters. This plasticizer migrates to the adhesive applied to the soft PVC and reduces the cohesive strength of the adhesive. The following are known as soft PVC adhesives comprising a (meth) acrylic polymer, but they have the following problems.

[0003] First, an adhesive for flexible PVC made of a (meth) acrylic polymer into which many polar groups are introduced has been proposed (Louis C. Graziano et al., Jou).
rnal of PLASTIC FILM & SH
EETING, Vol. 2, p. 95, 1986. reference). This adhesive has low initial adhesive strength and low tack. JP-A-4-154882, JP-A-5-105
857, Japanese Patent Publication No. 59-5634,
JP-A-18486 proposes a PSA adhesive made of a copolymer obtained by copolymerizing an alkyl (meth) acrylate and a nitrogen-containing vinyl monomer. This pressure-sensitive adhesive has problems in that it has low cohesive strength and is susceptible to migration of a plasticizer.

Japanese Patent Publication No. 58-1712 discloses an addition polymerization of an ethylenically unsaturated monomer whose homopolymer or copolymer can have a Tg of 273K or more in the presence of a (meth) acrylic polymer having a polar group. Pressure sensitive adhesives for flexible PVC made of graft polymers have been proposed.
This adhesive has a problem of low cohesion. Japanese Patent Publication No. 58-18958 proposes a pressure-sensitive adhesive for soft PVC comprising a polymer blend obtained by adding an acrylonitrile-butadiene copolymer rubber to a (meth) acrylic polymer. This pressure-sensitive adhesive has a problem that adhesion and cohesion are low.

Japanese Patent Publication No. 58-14474 proposes an adhesive for soft PVC containing a plasticizer.
This adhesive has a problem that the contained plasticizer bleeds and stains the punching blade. The conventional pressure-sensitive adhesive composition further has a problem that the pressure-sensitive adhesive strength decreases during long-term storage, that is, a problem that the shelf life is short.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive for flexible PVC which has an excellent balance between cohesive strength and initial adhesive strength, hardly causes a decrease in cohesive strength due to migration of a plasticizer, and has an excellent shelf life. To provide a pressure-sensitive adhesive composition used for Another object of the present invention is to provide an adhesive product and a bonded product that are excellent in balance between cohesive force and initial adhesive force, hardly cause a decrease in cohesive force due to migration of a plasticizer, and have excellent shelf life. is there.

[0007]

The composition for a pressure-sensitive adhesive of the present invention contains an acrylic polymer and an organic solvent. The organic solvent contains the acrylic polymer in a dissolved and / or dispersed state. The acrylic polymer is the following acrylic graft polymer (a). (a) Presence of a high glass transition point type polymer having a glass transition point of 273 K or more which is incompatible with a polymer of the monomer mixture containing a (meth) acrylic acid alkyl ester monomer. Below, the amount of the monomer mixture used is 100% of the total of the monomer mixture and the high glass transition point type polymer.
An acrylic graft polymer produced by a production method including a polymerization step of copolymerizing so as to be 60 to 95 parts by weight with respect to parts by weight.

The pressure-sensitive adhesive product of the present invention has a pressure-sensitive adhesive layer for soft PVC formed on at least one surface of a support comprising a film, a sheet, a tape, or a wallpaper by using the pressure-sensitive adhesive composition. This is a product that can be bonded to flexible polyvinyl chloride molded products. The bonded product of the present invention is a bonded product obtained by bonding two adherends, at least one of which is a soft polyvinyl chloride base material, via a layer made of the composition for a pressure-sensitive adhesive.

[0009]

[Description of the Means] [Composition for PSA for Flexible PVC] In the composition for PSA for flexible PVC of the present invention, the acrylic polymer which is dissolved and / or dispersed in an organic solvent contains (meth) A monomer mixture containing an alkyl acrylate monomer is not compatible with the polymer of the monomer mixture.
An acrylic graft polymer (a) produced by a production method including a polymerization step of copolymerizing in the presence of a high glass transition point type polymer having a glass transition point of 73 K or more. The high glass transition point type polymer is 273K or more, preferably 30K or more.
It is at least one selected from the group consisting of a homopolymer and a copolymer having a glass transition point of 0K or more.
When the glass transition point of the high glass transition point type polymer falls below the above range, the pressure-sensitive adhesive does not have sufficient cohesive force, and when the plasticizer is transferred, the cohesive force is greatly reduced.

The high glass transition point type polymer and the polymer of the monomer mixture containing the alkyl (meth) acrylate monomer are incompatible. Here, “not compatible” means that a tangent loss (tan δ, a ratio of storage elastic modulus G ′ to loss elastic modulus G ″: tan δ = G ″ /
G ′) means that the number of curve peaks is two.
That is, the peak caused by the polymer of the monomer mixture containing the (meth) acrylic acid alkyl ester monomer has a peak on the low temperature side, which is caused by the high glass transition point type polymer having a glass transition point of 273 K or more. Appears on the hot side. On the other hand,
“Compatible” means that the tangent loss curve peak becomes one peak without being separated into two.

The high glass transition point type polymer is, for example, 2 ×
10 ⁴ or more, preferably has a weight average molecular weight of 5 × 10 ⁴ or more. The weight average molecular weight is a value expressed in terms of standard polystyrene by gel permeation chromatography (hereinafter abbreviated as GPC) measurement. If the weight-average molecular weight is below the above range, the cohesive strength may be greatly reduced due to the transfer of the plasticizer. The high glass transition point type polymer is, for example,
Radical polymerization of α, β-unsaturated monomer containing at least one selected from the group consisting of styrene, vinyl acetate, acrylonitrile, methacrylonitrile and methyl methacrylate by bulk polymerization, solution polymerization and suspension polymerization It is made by doing.

Examples of the high glass transition point polymer include an organic solvent used for polymerization of a usual (meth) acrylic polymer,
For example, a commercially available thermoplastic resin that is dissolved in an organic solvent such as ethyl acetate or toluene can be used. As commercially available thermoplastic resins, for example, polystyrene, poly (acrylonitrile-styrene), polymethyl methacrylate, and polyvinyl acetate can be used. The (meth) acrylic acid alkyl ester monomer is not particularly limited as long as it is a (meth) acrylic acid alkyl ester usually used for an adhesive, but the alkyl group has 4 carbon atoms.
To -18, for example, butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, ( Meta)
At least one selected from the group consisting of isooctyl acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate is given.

The amount of the (meth) acrylic acid alkyl ester monomer used to obtain the acrylic graft polymer (a) is based on the total amount of the monomer mixture used.
68-99.89% by weight. If the amount of the (meth) acrylic acid alkyl ester monomer is outside the above range, the flexibility and tackiness of the pressure-sensitive adhesive may not be obtained. The monomer mixture used to obtain the acrylic graft polymer (a) may further include a reactive functional group-containing α, β-unsaturated monomer, if necessary. The reactive functional group-containing α, β-unsaturated monomer is at least one selected from the group consisting of a carboxyl group-containing α, β-unsaturated monomer and a hydroxyl group-containing α, β-unsaturated monomer. is there.

The carboxyl group-containing α, β-unsaturated monomer is not particularly limited as long as it is an α, β-unsaturated monomer having a carboxyl group. For example, acrylic acid, methacrylic acid, itaconic acid, croton At least one selected from the group consisting of unsaturated carboxylic acids such as acid, maleic anhydride, and maleic acid. Acrylic graft polymer
When a carboxyl group-containing α, β-unsaturated monomer is used to obtain (a), the amount of carboxyl group-containing α, β-unsaturated monomer is determined by the total amount of the monomer mixture used. For example, 0.1 to 10% by weight, preferably 2 to 8%
% By weight. When the amount of the carboxyl group-containing α, β-unsaturated monomer is less than 0.1% by weight, the cohesive force of the pressure-sensitive adhesive may be insufficient, and when it exceeds 10% by weight, the cohesive force becomes high. Too long, and the adhesive strength may decrease.

The hydroxyl group-containing α, β-unsaturated monomer is not particularly limited as long as it is an α, β-unsaturated monomer having a hydroxyl group. For example, 2-hydroxyethyl (meth) acrylate, From hydroxy group-containing polymerizable monomers such as 2-hydroxypropyl (meth) acrylate and polycaprolactone-modified 2-hydroxyethyl (meth) acrylate (trade name: Praxel F series (manufactured by Daicel Chemical Industries, Ltd.)) At least one selected from the group consisting of: To obtain an acrylic graft polymer (a),
When a β-unsaturated monomer is used, a hydroxyl group-containing α, β-
The amount of unsaturated monomer is, for example, 0.01 to 2% by weight, preferably 0.1 to 1% by weight, based on the total amount of the monomer mixture used. When the amount of the hydroxyl group-containing α, β-unsaturated monomer is less than 0.01% by weight, the crosslinking point becomes insufficient, so that the crosslinking density is not sufficient and the cohesive strength may be insufficient, and 2% by weight. %, The cohesive strength may be too high, and the cohesive strength may be too high, so that the adhesive strength may be reduced.

The monomer mixture used to obtain the acrylic graft polymer (a) contains a (meth) acrylic acid alkyl ester monomer as an essential component and contains a reactive functional group-containing α, β- Regardless of whether they further contain saturated monomers, they may further contain α, β-unsaturated monomers copolymerizable with these monomers. Α, β copolymerizable
The unsaturated monomer is not particularly limited, and examples thereof include aromatic α, β such as styrene and α-methylstyrene.
-Unsaturated monomers; vinyl esters such as vinyl acetate and vinyl propionate; N-containing α, β-unsaturated monomers such as N-vinylpyrrolidone and acryloylmorpholine;
At least one selected from the group consisting of α, β-unsaturated nitriles such as (meth) acrylonitrile; and unsaturated amides such as (meth) acrylamide and N-methylolacrylamide. The amount of the copolymerizable α, β-unsaturated monomer used to obtain the acrylic graft polymer (a) depends on the amount of the monomer It is, for example, 0 to 20% by weight relative to the total amount of the body mixture. If the amount of the copolymerizable α, β-unsaturated monomer exceeds 20% by weight, the polymer (a) becomes hard and the adhesive strength may be reduced.

The composition of the monomer mixture used to obtain the acrylic graft polymer (a) is such that the Tg of the polymer (a) is from 200 K to 240
It is preferable to use them in combination so as to obtain K. The amount of the monomer mixture used to obtain the acrylic graft polymer (a) is, for example, 60 to 100 parts by weight of the total of the monomer mixture and the high glass transition point type polymer.
95 parts by weight, preferably 70 to 90 parts by weight. When the amount of the monomer mixture exceeds 95 parts by weight, that is, when the amount of the high glass transition point type polymer is less than 5 parts by weight, the cohesive force may be significantly reduced due to the transfer of the plasticizer. Also,
If the amount of the monomer mixture is less than 60 parts by weight, that is, if the amount of the high glass transition point type polymer exceeds 40 parts by weight, the physical properties of the pressure-sensitive adhesive, for example, the initial tackiness may be greatly reduced.

The copolymerization of the monomer mixture and the high glass transition point type polymer is not particularly limited as long as it is a conventional polymerization method, but can be carried out by a solution polymerization method or a bulk polymerization method. The conditions for the copolymerization are appropriately set, for example, so that an acrylic copolymer having a weight average molecular weight within the range described below is produced. Industrially, a solution polymerization method is preferable in consideration of removal of heat of polymerization during polymerization and workability. Solvents that can be used in the solution polymerization method include, for example, aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; alicyclic hydrocarbons such as cyclohexane; and aliphatic hydrocarbons such as hexane and pentane. It is a hydrocarbon and may be a single solvent or a mixed solvent. The polymerization reaction can be initiated by irradiating energy rays such as ultraviolet rays, radiations, and electron beams, but it is industrially preferable to use a radical polymerization initiator used for producing an ordinary acrylic pressure-sensitive adhesive.

Examples of the radical polymerization initiator include organic peroxide-based and azo-based polymerization initiators. In particular, the organic peroxide-based polymerization initiator generates a larger amount of radicals that cause a hydrogen abstraction reaction of the polymer main chain than the azo-based polymerization initiator. Therefore, in order to grow a (meth) acrylic polymer portion derived from a monomer component from a high glass transition point type polymer, it is preferable to use an organic peroxide-based polymerization initiator. Examples of such an organic peroxide-based polymerization initiator include benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, tert-butyl peroxide.
Butyl peroxybenzoate and the like can be mentioned.

In this manner, an acrylic graft polymer (a) having a structure in which the (meth) acrylic polymer portion is branched from the high glass transition point polymer portion is obtained. The acrylic graft polymer (a) is, for example, 15 ×
10 ⁴ or more, preferably has a weight average molecular weight of 20 × 10 ⁴ or more. The weight average molecular weight of the polymer (a) is 15 × 1
If it is less than 0 ^4, not only large reduction in cohesive force after plasticizer migration, may be the initial adhesive force is also small. The organic solvent used in the pressure-sensitive adhesive composition of the present invention is not particularly limited as long as it is a liquid substance in which the acrylic graft polymer (a) can be dissolved and / or dispersed. For example, aromatic solvents such as toluene and xylene can be used. Aromatic hydrocarbons, esters such as ethyl acetate and butyl acetate, alicyclic hydrocarbons such as cyclohexane, ketones such as acetone and methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and pentane It is a single solvent selected from the group or a mixed solvent of two or more. The amount of the organic solvent is, for example, 100 to 400 parts by weight, and preferably 150 to 350 parts by weight, based on 100 parts by weight of the acrylic polymer. If the ratio is less than the above range, the viscosity may be too high to cause difficulty in the coating operation. If the ratio exceeds the range, the viscosity may be too low to perform the coating.

The pressure-sensitive adhesive composition of the present invention is characterized in that the acrylic graft polymer (a) is prepared using a monomer mixture containing a reactive functional group-containing α, β-unsaturated monomer. In
A crosslinking agent may be further included. The crosslinking agent has at least two functional groups per molecule that can react with the reactive functional groups of the acrylic polymer. As the crosslinking agent used in the present invention, a polyfunctional epoxy compound, a polyfunctional melamine compound, a polyfunctional isocyanate compound, a metal-based crosslinking agent,
Aziridine compounds and the like. In particular, a polyfunctional isocyanate compound is preferable in the reaction between a hydroxyl group and a carboxyl group.

The polyfunctional epoxy compound is not particularly limited as long as it is a compound having two or more epoxy groups per molecule. For example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether,
1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin,
N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N-diglycidylaniline, N, N-diglycidyltoluidine And the like,
Each may be used alone, or two or more may be used in combination.

The polyfunctional melamine compound is
There is no particular limitation as long as the compound has two or more methylol groups, alkoxymethyl groups, or imino groups.
For example, hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentyloxymethyl melamine, etc. are used, and each is used alone or two or more are used in combination. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups per molecule. For example, tolylene diisocyanate (TDI),
4,4'-diphenylmethane diisocyanate (MD
I), hexamethylene diisocyanate, xylylene diisocyanate, meta-xylylene diisocyanate,
Isocyanate compounds such as 1,5-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate; burette polyisocyanate compounds such as Sumidur N (manufactured by Sumitomo Bayer Urethane Co.); IL, H
L (manufactured by Bayer AG) and Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.); polyisocyanate compounds having an isocyanurate ring; adduct poly such as Sumidur L (manufactured by Sumitomo Bayer Urethane Co., Ltd.) Examples thereof include isocyanate compounds and adduct polyisocyanate compounds such as Coronate L (manufactured by Nippon Polyurethane Co., Ltd.). These can be used alone,
Two or more can be used in combination. Also, blocked isocyanates in which the isocyanate groups of these polyvalent isocyanate compounds have been reacted with a masking agent having active hydrogen to be inactivated can be used.

Examples of the metal-based crosslinking agent include acetylacetone, methyl acetoacetate, acetoacetate, metals such as aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, zirconium, chromium, and tin. Metal chelate compounds coordinated with ethyl acetate, ethyl lactate, methyl salicylate and the like can be mentioned. These can be used alone or in combination of two or more. As the aziridine compound, N,
N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-
β-aziridinyl propionate, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinyl phosphoxide, N, N′-diphenylethane-4,4′-bis (1 -Aziridinecarboxamide) and the like. These can be used alone or in combination of two or more.

The amount of the crosslinking agent used is, for example, 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the acrylic polymer (a). When the amount of the crosslinking agent is less than 0.1 part by weight, the crosslinking point is insufficient, so that the crosslinking density is insufficient and the cohesive force may be insufficient,
If the amount exceeds 10 parts by weight, the crosslinking density becomes too high,
Adhesive strength may decrease. The pressure-sensitive adhesive composition of the present invention can contain a tackifier commonly used for pressure-sensitive adhesives, if necessary. Examples of the tackifier include (polymerized) rosin type, (polymerized) rosin ester type, terpene type, terpene phenol type, cumarone type, cumarone indene type,
Styrene resin, xylene resin, phenol resin,
A tackifier such as a petroleum resin is used. These are 1
Species or a combination of two or more can be used. The amount of the tackifier is based on 100 parts by weight of the acrylic polymer (a).
For example, it is 5 to 100 parts by weight, preferably 10 to 50 parts by weight. If the ratio is below the above range, the adhesion to the adherend may not be improved. If the ratio is above the range, the tack may decrease and the adhesion may decrease.

The pressure-sensitive adhesive composition of the present invention may contain, if necessary, a filler, a pigment, a diluent, an antioxidant, It may contain at least one additive selected from the group consisting of an ultraviolet absorber, an ultraviolet stabilizer and the like. The pressure-sensitive adhesive composition of the present invention is used, for example, for producing a pressure-sensitive adhesive product and a bonded product by a method described below. [Adhesive Product and Laminated Product] The adhesive product of the present invention has a pressure-sensitive adhesive layer for soft PVC formed using the pressure-sensitive adhesive composition of the present invention on at least one surface of a support,
It can be bonded to flexible polyvinyl chloride molded products. Examples of the support include at least one selected from a film, a sheet, a tape, and a wallpaper.

The bonded article of the present invention is obtained by laminating two adherends via a layer made of the pressure-sensitive adhesive composition of the present invention (a flexible PVC pressure-sensitive adhesive layer). At least one of the two adherends is a soft vinyl chloride base material. The pressure-sensitive adhesive layer for flexible PVC is, for example, a composition for a pressure-sensitive adhesive according to the present invention, which comprises an acrylic graft polymer (a) and an organic solvent in which the acrylic graft polymer (a) is dissolved and / or dispersed. Is applied to an object to be coated, followed by drying and crosslinking. As described above, each monomer mixture used in the polymerization step for producing the acrylic graft polymer (a) may further contain a reactive functional group-containing α, β-unsaturated monomer. did it. When the monomer mixture contains such a reactive functional group-containing α, β-unsaturated monomer, the pressure-sensitive adhesive composition contains at least two functional groups capable of reacting with the reactive functional group. It could further comprise a crosslinker.

Therefore, in the above-mentioned crosslinking step, the organic solvent is removed from the pressure-sensitive adhesive composition by applying such a pressure-sensitive adhesive composition to an object to be coated and then drying, thereby obtaining an acrylic graft polymer (a ) Can be crosslinked. As the object to be coated, for example, a separator, a support, a substrate, and the like described below are appropriately used. Crosslinking of the acrylic graft polymer (a) is carried out by, for example, room temperature crosslinking which is allowed to stand at room temperature for one week or more, or high temperature accelerated crosslinking which promotes the reaction in a constant temperature room at 40 to 50 ° C.

When the acrylic graft polymer (a) is produced using a monomer mixture containing a reactive functional group-containing α, β-unsaturated monomer, the reactive functional group of the acrylic polymer Crosslinking is performed by reaction with a crosslinking agent having at least two functional groups capable of reacting with the group. The crosslinking agent used here is
It is the same as the crosslinking agent used in the composition for an adhesive. The conditions for crosslinking may be appropriately set according to the crosslinking agent used. The adhesive product of the present invention may further include a separator attached to one or both surfaces of the adhesive layer for flexible PVC. The pressure-sensitive adhesive product of the present invention includes two flexible PVC adhesive layers, a support sandwiched between the flexible PVC adhesive layers, and a flexible PVC adhesive layer on the side opposite to the support. A separator attached to one side may be further provided.

The adhesive product of the present invention may further comprise a separator attached to one side of the soft PVC adhesive layer, and a base material attached to the other side of the soft PVC adhesive layer. The substrate is, for example, a flexible polyvinyl chloride substrate. Examples of the separator used in the present invention include, for example, a paper substrate having a surface directly subjected to release treatment with a release agent such as silicone, a laminated film in which a polyethylene film is laminated on the back surface of the release-treated paper substrate, polyester -A plastic film such as polyethylene or polypropylene is used. The adhesive product of the present invention,
For example, a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a double-sided tape, etc. for soft PVC; or a soft pressure-sensitive adhesive sheet, a soft PVC pressure-sensitive adhesive tape, a soft PVC pressure-sensitive adhesive label, or the like.

The adhesive product of the present invention is produced by the following method, but the production method is not limited. On one side of the separator, the pressure-sensitive adhesive composition of the present invention was coated with at least an acrylic polymer (a), a crosslinking agent and an organic solvent, and after drying, formed on the separator surface The pressure-sensitive adhesive layer is superposed on one surface of another separator, a base material described later or a support described below, and pressure is applied (for example, 1 to 1).
(At a pressure of 5 kg / cm ² ). The pressure-sensitive adhesive layers formed on the surfaces of the two separators can be superposed on both surfaces of a support described later, and similarly transferred under pressure. On one or both surfaces of the support, a pressure-sensitive adhesive composition of the present invention, which contains at least an acrylic polymer (a), a cross-linking agent and an organic solvent, is applied, dried, and the obtained pressure-sensitive adhesive A separator is attached so as to cover the agent layer.

The dry thickness of the pressure-sensitive adhesive layer is, for example, 10 to 1
00 μm. Drying is performed, for example, by leaving it in a hot air dryer at 70 to 100 ° C. for 2 to 10 minutes. The pressure-sensitive adhesive composition and the pressure-sensitive adhesive product of the present invention are applied to a flexible polyvinyl chloride molded product. The soft polyvinyl chloride molded article is an adherend to which an adhesive layer is adhered, and may be, for example, a sheet, tape, wallpaper, foam (foam), and the like. In the adhesive product of the present invention, the support can be a flexible polyvinyl chloride molded article.

[0033]

In the acrylic graft polymer (a) of the pressure-sensitive adhesive composition of the present invention, the high glass transition point type polymer has
The polymer portion of the monomer mixture containing the alkyl (meth) acrylate monomer is dispersed in the polymer portion, and the high glass transition point polymer portion and the polymer portion of the monomer mixture are chemically dispersed. Tied together. This suggests that a simple blend of a polymer of a monomer mixture containing an alkyl (meth) acrylate monomer and a polymer having a high glass transition point tends to separate in a solution state. In the system of the present invention, this tendency can be demonstrated by not showing such a tendency.
The high glass transition point type polymer part has a microdomain structure with respect to the polymer part of the monomer mixture containing the alkyl (meth) acrylate monomer, and the physical part of the sticky polymer part Since it acts as a crosslinking agent, the pressure-sensitive adhesive composition of the present invention forms a pressure-sensitive adhesive exhibiting high cohesive strength without impairing its adhesiveness even when applied to a flexible polyvinyl chloride molded article.

[0034]

FIG. 1 is a sectional view of one embodiment of the adhesive product of the present invention. This adhesive product is a double-sided adhesive tape 5, a support 1, an adhesive layer 2 for soft PVC, a separator 3
Having. The pressure-sensitive adhesive layer 2 for flexible PVC is formed by cross-linking an acrylic cross-linked copolymer (crosslinked from an acrylic graft polymer (a)) produced by a production method including a step of drying and cross-linking the pressure-sensitive adhesive composition of the present invention. ) Are formed on both surfaces of the support 1. The separator 3 is, for example, release paper, and is attached to one surface of the soft PVC adhesive layer 2 so as to cover one surface thereof. One surface of the pressure-sensitive adhesive layer 2 is a surface opposite to the one surface attached to the support 1.

The support is, for example, a conventionally known paper, plastic film, foam sheet, nonwoven fabric or the like. In the adhesive product of the present invention, the support can be a flexible polyvinyl chloride molded article (eg, film, sheet, tape, wallpaper). FIG. 2 is a sectional view of another embodiment of the adhesive product of the present invention. This adhesive product is a coreless double-sided pressure-sensitive adhesive tape (double-sided pressure-sensitive adhesive tape without a support) 6, and has a pressure-sensitive adhesive layer 2 for soft PVC and a separator 3.
The pressure-sensitive adhesive layer 2 for soft PVC is made of an acrylic cross-linked copolymer (acryl-based graft polymer (a)) produced by a production method including a step of drying and cross-linking the pressure-sensitive adhesive composition of the present invention.
Is crosslinked) as the main agent. Separator 3
Is a release paper, for example, which is attached to both sides of the soft PVC adhesive layer 2 so as to cover both sides.

FIG. 3 is a sectional view of another embodiment of the adhesive product of the present invention. This adhesive product has an adhesive layer 2 for soft PVC, a separator 3 and a substrate 4. The pressure-sensitive adhesive layer 2 for flexible PVC is formed by cross-linking an acrylic cross-linked copolymer (crosslinked from an acrylic graft polymer (a)) produced by a production method including a step of drying and cross-linking the pressure-sensitive adhesive composition of the present invention. ) As the main agent. The separator 3 is, for example, release paper, and is attached to one surface of the soft PVC adhesive layer 2 so as to cover one surface thereof. The base material 4 is a soft polyvinyl chloride base material (eg, film, sheet, tape, wallpaper).

FIG. 4 is a sectional view of another embodiment of the adhesive product of the present invention. This adhesive product has an adhesive layer 2 for soft PVC, a separator 3 and a substrate 7. The pressure-sensitive adhesive layer 2 for flexible PVC is formed by cross-linking an acrylic cross-linked copolymer (crosslinked from an acrylic graft polymer (a)) produced by a production method including a step of drying and cross-linking the pressure-sensitive adhesive composition of the present invention. ) As the main agent. The separator 3 is, for example, release paper, and is attached to one surface of the soft PVC adhesive layer 2 so as to cover one surface thereof. The base material 7 is, for example, an aluminum foil; a sheet of polyolefin such as polyethylene or polypropylene.

Hereinafter, specific examples of the present invention will be described together with comparative examples, but the present invention is not limited to the following examples. In the following Examples and Comparative Examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively. [Production of pressure-sensitive adhesive composition]-Production example A1- 210 parts of ethyl acetate and 100 parts of polystyrene (Stylon 666R, manufactured by Asahi Kasei Kogyo Co., Ltd.) were measured with a thermometer, a stirrer, an inert gas introduction pipe, a reflux condenser, and a dropper. A four-necked flask equipped with a funnel was charged, and polystyrene was dissolved in ethyl acetate. Next, 379.6 parts of butyl acrylate, 20 parts of acrylic acid, and 2 parts of acrylic acid were added to the flask.
133.3 parts of 400 parts of the monomer mixture with 0.4 part of hydroxyethyl were charged. While stirring the content of the flask under a nitrogen stream and maintaining the content at 80 ° C., 0.32 parts of Niper BMT-K40 (organic peroxide manufactured by NOF Corporation) was added to the content as a polymerization initiator to carry out polymerization. Started. Ten minutes after the start of the polymerization, the remaining part (266.7 parts) of the monomer mixture, 76 parts of toluene, 76 parts of ethyl acetate, and 0.8 part of Niper BMT-K40 (organic peroxide manufactured by NOF Corporation) were added. The mixture was dropped continuously over 1.5 hours, and after completion of the dropping, 76 parts of ethyl acetate, 490 parts of toluene and 2,
1.2 parts of 2′-azobis (2-methylbutyronitrile) (manufactured by Nippon Hydrazine Industry Co., Ltd .; hereinafter abbreviated as ABNE) were added, and the mixture was reacted at 85 ° C. for 5 hours to obtain a solid content of 34.5%.
Viscosity 3670 cps (25 ° C, B-type viscometer, the same applies hereinafter)
A solution of an acrylic copolymer was obtained.

-Production Examples A2 to A11 and Comparative Production Example a1-The procedure of Production Example A1 was repeated except that the reaction raw materials and / or reaction conditions were changed as shown in Tables 1 and 3, and the results are shown in Table 3. A solution of an acrylic copolymer having a solid content, viscosity, and weight average molecular weight was obtained. -Comparative Production Examples a2 to a7-The operations of Production Example A1 were repeated except that the reaction raw materials and / or reaction conditions were changed as shown in Tables 2 and 4, and the solid content, viscosity, and weight average shown in Table 4 were obtained. A solution of an acrylic copolymer having a molecular weight was obtained.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

Example B1- Coronate L55E (Polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd .: solid content 55) was added to a solution (solid content: 100 parts) of the acrylic copolymer obtained in Production Example A1.
%) Was mixed to prepare a pressure-sensitive adhesive composition. -Examples B2 to B11 and Comparative Examples b1 to b5-The procedure of Example B1 was repeated except that the amounts of the solution of the acrylic copolymer and the cross-linking agent were changed as shown in Table 5, and the pressure-sensitive adhesive composition was used. Was prepared. -Example C1-The pressure-sensitive adhesive composition obtained in Example B1 was applied on one surface of one release paper (manufactured by Fujimori Kogyo Co., Ltd .: 70K-818T / EF) so that the thickness after drying was 50 µm. After that, 10
It was dried at 0 ° C. for 2 minutes and cured at 23 ° C. for 7 days. Then, a 50 μm-thick soft polyvinyl chloride sheet (manufactured by Okamoto Corporation) is overlaid on one side and pressurized, and the adhesive composition is transferred onto one side of the soft polyvinyl chloride sheet to form a soft polyvinyl chloride adhesive sheet (with release paper). ) Got.

Further, the pressure-sensitive adhesive composition obtained in Example B1 was applied to two release papers (70K-818, manufactured by Fujimori Kogyo KK).
T / EF) is applied to each side so that the thickness after drying is 75 μm, dried at 100 ° C. for 3 minutes, and then the coated surface of the pressure-sensitive adhesive composition of two release papers is coated with one nonwoven fabric. Double-sided tape with a thickness of 150 μm (with double-sided release paper)
Was prepared. -Examples C2 to C11 and Comparative examples c1 to c5- The procedure of Example C1 was repeated except that the pressure-sensitive adhesive composition was changed as shown in Table 5, to produce a soft PVC pressure-sensitive adhesive sheet and a double-sided tape.

Comparative Example c6- A commercially available double-sided tape for flexible PVC (a double tack tape # 577 manufactured by Sekisui Chemical Co., Ltd.) was prepared for comparison. -Comparative Example c7- A commercially available double-sided tape for flexible PVC (double-sided adhesive tape No. 501M manufactured by Nitto Electric Industrial Co., Ltd.) was prepared for comparison. -Comparative Example c8-A commercially available double-sided tape for flexible PVC (double-sided adhesive tape No. 5000CX manufactured by Nitto Electric Industrial Co., Ltd.) was prepared for comparison.

The flexible PVC adhesive sheet and the double-sided tape obtained in Examples and Comparative Examples were subjected to JIS-Z023.
7 (1991), the holding power and the adhesive strength were measured, and the results are shown in Table 5.

[0048]

[Table 5]

The holding force is a stainless steel plate (SUS30
4) A 20 mm × 20 mm pressure-sensitive adhesive sheet is stuck thereon, and the temperature is kept at 80 ° C. 20 minutes after the sticking, and a time of falling after applying a load of 1 kg after 20 minutes, or
It was indicated by the magnitude of the deviation measured 24 hours after the application of the load. The adhesive strength of the pressure-sensitive adhesive sheet was shown by an initial value and a value after heating promotion. The initial value is a 25 mm wide adhesive sheet placed on an aluminum plate (JI) in an atmosphere of 23 ° C. and 65% RH.
SA1050P: 1 mm in thickness), a 2 kg rubber roller was reciprocated once and bonded together, and after 25 minutes, the strength when peeled at a speed of 300 mm / min in a 180-degree direction was measured. After heating, the adhesive sheet was left in an atmosphere of 80 ° C. for 3 days, further left in an atmosphere of 23 ° C. and 65% RH for 2 hours, cut into a 20 mm width, and cut on an aluminum plate.
A rubber roller having a weight of 3 kg was reciprocated three times to be bonded, and after 24 hours, the strength at the time of peeling at a speed of 300 mm / min in the direction of 180 ° was measured.

The adhesive strength of the double-sided tape was shown by an initial value and a value after acceleration of heating. The initial value is that a PET film subjected to corona discharge treatment is lined from one side of a double-sided tape in an atmosphere of 23 ° C. and 65% RH, and the double-sided tape is cut to a width of 20 mm. Bisheet (Okamoto Co., Ltd., # 480, plasticizer 50 phr, aluminum plate fixed on the back with commercially available double-sided adhesive tape)
2kg rubber roller is reciprocated 3 times and bonded.
After 5 minutes, the strength at the time of peeling in the direction of 180 degrees at a speed of 300 mm / min was measured. The value after the heating was promoted was a double-sided tape backed with a corona-treated PET film and cut to a width of 20 mm, and a soft PVC sheet having a thickness of 2 mm (manufactured by Okamoto Co., Ltd., # 480, 50 phr plasticizer, commercially available back side) Aluminum plate fixed with double-sided adhesive tape)
2kg rubber roller is reciprocated 3 times and bonded.
Leave in 0 ° C atmosphere for 3 days, then 23 ° C, 65% R
After leaving for 2 hours in an atmosphere of H, the strength at the time of peeling in the direction of 180 degrees at a speed of 300 mm / min was measured.

As shown in Table 5, examples of the present invention include those suitable for a single-sided adhesive sheet and those suitable for a double-sided adhesive tape depending on the molecular weight of the obtained polymer (acrylic graft polymer). However, it is excellent in initial adhesive strength, suppresses the decrease in cohesive force even for the migration of plasticizer from soft PVC, and the adhesive strength is maintained at a considerably higher dimension than the comparative example even after accelerated heating. Understand. The glass transition temperature (Tg: K) of the produced acrylic copolymer was determined according to the following equation using the following data. Acrylic acid: 379 (K) Methyl acrylate: 281 (K) Ethyl acrylate: 251 (K) Butyl acrylate: 219 (K) 2-ethylhexyl acrylate: 203 (K) 2-hydroxyethyl acrylate: 258 (K) K) Methyl methacrylate: 378 (K) Vinyl acetate: 305 (K) Acrylonitrile: 398 (K) Styrene: 373 (K)

[0052]

(Equation 1)

[0053]

The pressure-sensitive adhesive composition of the present invention contains an acrylic graft polymer (a) and an organic solvent, so that it has an excellent balance between cohesive force and initial adhesive force, and has a low cohesive force due to the transfer of a plasticizer. It can be used to make a pressure-sensitive adhesive layer for flexible PVC which is hardly deteriorated and has a long shelf life. The pressure-sensitive adhesive composition of the present invention comprises a monomer mixture containing a reactive functional group-containing α,
When a β-unsaturated monomer is further contained, there is an additional advantage that the cohesion can be arbitrarily controlled by using a crosslinking agent having a functional group which reacts with these reactive functional groups.

The pressure-sensitive adhesive composition of the present invention has at least a functional group capable of reacting with a reactive functional group when the monomer mixture further contains a reactive functional group-containing α, β-unsaturated monomer. When the crosslinker having two crosslinkers is further included, there is an additional advantage that a sufficient cohesive force can be obtained with a small amount of the crosslinker. Since the pressure-sensitive adhesive product of the present invention has a pressure-sensitive adhesive layer for soft PVC formed using the pressure-sensitive adhesive composition of the present invention, when bonded to a soft polyvinyl chloride molded product, the cohesive force and the initial It has an excellent balance of adhesive strength, hardly causes a decrease in cohesive force due to migration of a plasticizer, and has an excellent shelf life.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the adhesive product of the present invention.

FIG. 2 is a sectional view of one embodiment of the adhesive product of the present invention.

FIG. 3 is a cross-sectional view of one embodiment of the adhesive product of the present invention.

FIG. 4 is a sectional view of one embodiment of the adhesive product of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support body 2 Adhesive layer 3 Separator 4 Substrate 5 Double-sided adhesive tape 6 Coreless double-sided adhesive tape

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C09J 7/02 C09J 7/02 Z // C08L 33:00 (72) Inventor Yasumasa Tanaka Nishi Suita-shi, Osaka 5-8 Onarimachi Nippon Shokubai Co., Ltd. (72) Inventor Meiwa Baba Meiwa, 5-8 Nishimitabicho, Suita-shi, Osaka Prefecture Nippon Shokubai Co., Ltd. (72) Masatoshi Yoshida 5 Nishimitabicho, Suita-shi, Osaka No. 8 Inside Nippon Shokubai Co., Ltd. (72) Nobuhiro Kobayashi No. 5-8 Nishiomibashicho, Suita-shi, Osaka

Claims (3)

[Claims] 1. A pressure-sensitive adhesive composition comprising an acrylic polymer and an organic solvent in which the acrylic polymer is dissolved and / or dispersed, wherein the acrylic polymer is an alkyl (meth) acrylate monoester. The monomer mixture containing the monomer in the presence of a high glass transition point type polymer having a glass transition point of 273K or more which is incompatible with the polymer of the monomer mixture, Is from 60 to 95 parts by weight based on 100 parts by weight of the total of the monomer mixture and the high glass transition point type polymer, and the acrylic graft weight produced by the production method including the polymerization step of copolymerizing is used. A composition for a pressure-sensitive adhesive for soft PVC, which is a united product. 2. A pressure-sensitive adhesive layer for soft PVC formed by using the pressure-sensitive adhesive composition according to claim 1 on at least one surface of a support comprising a film, a sheet, a tape, or a wallpaper, An adhesive product that can be attached to flexible polyvinyl chloride molded products. 3. A bonded product obtained by bonding two adherends, at least one of which is a soft polyvinyl chloride base material, via a layer comprising the composition for a pressure-sensitive adhesive according to claim 1.