JPH08165462A - Composition for tacky adhesive and tacky adhesive product - Google Patents

Abstract

PURPOSE: To provide a tacky adhesive composition containing an acrylic graft polymer produced by a specific method, having well-balanced cohesive and adhesive forces, resistant to the lowering of cohesive force caused by the migration of plasticizer and giving a tacky adhesive for a soft vinyl chloride article having excellent shelf life. CONSTITUTION: This composition for the production of a tacky adhesive for molded soft PVC article is produced by dissolving and/or dispersing (A) an acrylic graft polymer obtained by copolymerizing (i) a monomer mixture containing an alkyl (meth)acrylate monomer [e.g. butyl (meth)acrylate] in the presence of (ii) a high glass-transition temperature polymer incompatible with the polymer derived from the component A and having a glass transition temperature of >=273 deg.K in (B) an organic solvent. The component (ii) can be produced e.g. by the radical polymerization of an α,β-unsaturated monomer selected from styrene, vinyl acetate, etc. The copolymerization of the components (i) and (ii) is preferably carried out by a solution polymerization method using an organic peroxide-type radical polymerization initiator.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product, and more particularly to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product applied to a soft polyvinyl chloride molded article.

[0002]

2. Description of the Related Art Soft vinyl chloride (that is, soft polyvinyl chloride or soft vinyl chloride resin) is a dioctyl phthalate.
It contains low molecular weight plasticizers such as phthalates such as dibutyl phthalate, dioctyl adipate, dioctyl azelate and other dibasic acid esters, and phosphoric acid esters. This plasticizer transfers to the adhesive applied to the soft vinyl chloride and reduces the cohesive strength of the adhesive.

Therefore, the pressure-sensitive adhesive for soft vinyl chloride is designed in various ways in order to prevent the decrease in cohesive force due to the plasticizer.
Examples are given below. Adhesives for soft PVC, which are composed of (meth) acrylic polymers having many polar groups introduced, have been proposed (Louis C. Graziano et al.,
Journalof PLASTIC FILM &
SHEETING, Vol. 2, p. 95, 1986.
reference). This adhesive has low initial adhesion and low tack.

Japanese Unexamined Patent Publication Nos. 4-154882 and 5
-1085787, Japanese Patent Publication No. 59-5634,
Japanese Unexamined Patent Publication (Kokai) No. 2-18486 proposes a pressure-sensitive adhesive for soft vinyl chloride, which is composed of a copolymer obtained by copolymerizing an alkyl (meth) acrylate and a nitrogen-containing vinyl monomer. This pressure-sensitive adhesive has a problem that it has a low cohesive force and is susceptible to the transfer of the plasticizer.

Japanese Patent Publication No. 58-1712 discloses an addition-polymerization of an ethylenically unsaturated monomer having a Tg of 273 K or more in a homopolymer or a copolymer in the presence of a (meth) acrylic polymer having a polar group. There has been proposed a soft vinyl chloride adhesive comprising a graft polymer.
This adhesive has a problem of low cohesive strength. Japanese Examined Patent Publication (Kokoku) No. 58-18958 proposes a pressure-sensitive adhesive for soft vinyl chloride, which comprises a polymer blend obtained by adding an acrylonitrile-butadiene copolymer rubber to a (meth) acrylic polymer. This adhesive has a problem of low cohesive strength with the adhesive.

Japanese Patent Publication No. 58-14474 proposes an adhesive for soft PVC containing a plasticizer. This adhesive has a problem that the contained plasticizer may bleed or stain the punching blade.

[0007]

An object of the present invention is to provide a pressure-sensitive adhesive for soft vinyl chloride which has an excellent balance between cohesive force and adhesive force, is less likely to cause a decrease in cohesive force due to migration of a plasticizer, and has excellent shelf life. It is to provide a composition for an adhesive to be used. Another object of the present invention is to provide an adhesive product which has an excellent balance between cohesive strength and adhesive strength, is less likely to cause a decrease in cohesive strength due to migration of a plasticizer, and has an excellent shelf life.

[0008]

A pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition for producing a soft polyvinyl chloride pressure-sensitive adhesive applied to a soft polyvinyl chloride molded article, which is 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) or the following acrylic block polymer.
It is (b). (a) Presence of a high glass transition type polymer having a glass transition point of 273 K or more, which is incompatible with the monomer mixture containing the (meth) acrylic acid alkyl ester monomer and the polymer of the monomer mixture. An acrylic graft polymer produced by a production method including a polymerization step of copolymerizing below. (b) An acrylic block polymer produced by a production method including a preparation step, a first polymerization step, an addition step, and a second polymerization step. In addition, the preparatory process is polyvalent mercaptan and 273K.
It is a step of preparing a first mixture containing the first α, β-unsaturated monomer capable of forming the high glass transition point type polymer having the above glass transition point. The first polymerization step starts with the mercapto group of the polyvalent mercaptan as the first α,
In this step, radical polymerization of β-unsaturated monomer is carried out to obtain a reaction mixture. The addition step is a reaction that can form a polymer that is incompatible with the high glass transition point polymer, and that a monomer mixture containing a (meth) acrylic acid alkyl ester monomer is obtained in the first polymerization step. This is a step of obtaining a second mixture in addition to the mixture. The second polymerization step is a step of radically polymerizing the monomers contained in the second mixture.

In the pressure-sensitive adhesive composition of the present invention, the monomer mixture used for producing the acrylic graft polymer (a) or the acrylic block polymer (b) has a reactive functional group-containing α, It may further contain a β-unsaturated monomer. When the monomer mixture further contains a reactive functional group-containing α, β-unsaturated monomer, the adhesive composition of the present invention has at least two functional groups capable of reacting with the reactive functional group. It may further include a crosslinking agent having.

The pressure-sensitive adhesive product of the present invention is provided with a pressure-sensitive adhesive layer for soft vinyl chloride formed by using the above-mentioned pressure-sensitive adhesive composition of the present invention, and is applied to a soft polyvinyl chloride molded article. The pressure-sensitive adhesive product of the present invention is a soft polyvinyl chloride pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition of the present invention, and a soft polyvinyl chloride base attached to one side or both sides of the soft vinyl chloride pressure-sensitive adhesive layer. The material may be provided.

[0012]

[Explanation of means]

[Composition for pressure-sensitive adhesive] The composition for pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive composition for producing a pressure-sensitive adhesive for soft vinyl chloride applied to a soft polyvinyl chloride molded article, which comprises an acrylic polymer and an organic polymer. Including solvent. The organic solvent contains the acrylic polymer in a dissolved and / or dispersed state. The acrylic polymer is the acrylic graft polymer (a) or the acrylic block polymer (b).

First, the acrylic graft polymer (a) will be described. Acrylic graft polymer (a) is a high glass transition having a glass transition point of 273 K or higher, which is incompatible with a monomer mixture containing a (meth) acrylic acid alkyl ester monomer. It is made by a manufacturing method including a polymerization step of copolymerizing in the presence of a dot-type polymer.

The high glass transition type polymer has a glass transition point of 273 K or higher, preferably 300 K or higher,
It is at least one selected from the group consisting of homopolymers and copolymers. When the glass transition point of the high glass transition point type polymer is 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 type polymer is incompatible with the polymer of the monomer mixture containing the (meth) acrylic acid alkyl ester monomer. Here, “not compatible” means tangent loss (tan δ, ratio of storage elastic modulus G ′ and loss elastic modulus G ″: tan δ = G ″ / in dynamic viscoelasticity measurement of a polymer.
It means that the number of curve peaks of G ′) becomes two.
That is, the peak due to the polymer of the monomer mixture containing the (meth) acrylic acid alkyl ester monomer has a peak due to the high glass transition point type polymer having a glass transition point of 273 K or more on the low temperature side. Appears on the high temperature side. On the other hand,
"Compatible" means that the curve peak of this tangent loss does not separate into two but becomes one peak.

The high glass transition 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 less than the above range, the cohesive force may be significantly reduced due to migration of the plasticizer.

The high glass transition type polymer includes, for example, a bulk of α, β-unsaturated monomer containing at least one selected from the group consisting of styrene, vinyl acetate, acrylonitrile, methacrylonitrile and methyl methacrylate. It is produced by radical polymerization by a polymerization method, a solution polymerization method, or a suspension polymerization method. As the high glass transition type polymer,
It is also possible to use a commercially available thermoplastic resin that is soluble in an organic solvent used for usual polymerization of (meth) acrylic polymers, for example, an organic solvent such as ethyl acetate or toluene.
As the commercially available thermoplastic resin, for example, polystyrene, poly (acrylonitrile-styrene), polymethylmethacrylate, or 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 that is usually used for pressure-sensitive adhesives, but the alkyl group has 4 to 18 carbon atoms. There are things, for example,
Butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n- (meth) acrylate
Octyl, isooctyl (meth) acrylate, (meth)
At least one selected from the group consisting of lauryl acrylate and stearyl (meth) acrylate can be mentioned.

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.
It is 68 to 99.89% by weight. When the amount of the (meth) acrylic acid alkyl ester monomer is out of the above range, flexibility and tackiness as an adhesive may not be obtained.

The monomer mixture used for obtaining the acrylic graft polymer (a) may further contain a reactive functional group-containing α, β-unsaturated monomer, if necessary. The reactive functional group-containing α, β-unsaturated monomer includes a carboxyl group-containing α, β-unsaturated monomer and a hydroxyl group-containing α, β.
-At least one selected from the group consisting of unsaturated monomers.

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, and examples thereof include acrylic acid, methacrylic acid, itaconic acid and croton. At least one selected from the group consisting of unsaturated carboxylic acids such as acids, maleic anhydride, and maleic acid can be used. Acrylic graft polymer
When a carboxyl group-containing α, β-unsaturated monomer is used to obtain (a), the amount of the carboxyl group-containing α, β-unsaturated monomer is the total amount of the monomer mixture used. With respect to, 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. The adhesive strength may be reduced due to excessive passage.

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-containing polymerizable monomers such as 2-hydroxypropyl (meth) acrylate and polycaprolactone-modified (meth) acrylic acid 2-hydroxyethyl (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), a hydroxyl group-containing α,
When using a β-unsaturated monomer, hydroxyl group-containing α, β-
The amount of unsaturated monomers 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 may be insufficient and the cohesive force may be insufficient. If it exceeds%, the crosslink density may become high, or the cohesive force may become too high, resulting in a decrease in the adhesive force.

The monomer mixture used for obtaining 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-insoluble component. It may further include an α, β-unsaturated monomer copolymerizable with these monomers, whether or not they further include saturated monomers. Copolymerizable α, β
-The unsaturated monomer is not particularly limited, and examples thereof include aromatic α and β such as styrene and α-methylstyrene.
-Unsaturated monomers; vinyl esters such as vinyl acetate and vinyl propionate; N-group-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; 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) is determined by considering the tack and the balance between adhesive strength and cohesive strength. It is, for example, 0 to 20% by weight, based on the total amount of the body mixture. When the amount of the copolymerizable α, β-unsaturated monomer exceeds 20% by weight, the polymer (a) becomes hard and the adhesive strength may be lowered.

The composition of the monomer mixture used to obtain the acrylic graft polymer (a) has a Tg of 200 K to 240 K from the balance of tack and adhesive strength.
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 60 parts by weight based on 100 parts by weight of the total of the monomer mixture and the high glass transition type polymer.
95 parts by weight, preferably 70 to 90 parts by weight. If the amount of the monomer mixture exceeds 95 parts by weight, that is, if the amount of the high glass transition point polymer is less than 5 parts by weight, the cohesive force may significantly decrease due to the migration 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 polymer exceeds 40 parts by weight, the physical properties of the pressure-sensitive adhesive may be significantly deteriorated.

The copolymerization of the monomer mixture and the high glass transition type polymer is not particularly limited as long as it is a conventional polymerization method, but it can be performed by a solution polymerization method or a bulk polymerization method. The conditions of 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, the solution polymerization method is preferable in consideration of removal of the 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; aliphatic hydrocarbons such as hexane and pentane. It is a hydrocarbon and may be a single solvent or a mixed solvent. The initiation reaction of the polymerization reaction can be carried out by irradiation with energy rays such as ultraviolet rays, radiation and electron beams, but it is industrially preferable to use a radical polymerization initiator which is usually used in the production of acrylic pressure-sensitive adhesives.

Examples of the radical polymerization initiator include organic peroxide type and azo type polymerization initiators. In particular, the organic peroxide-based polymerization initiator produces 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 the (meth) acrylic polymer portion derived from the monomer component from the high glass transition point polymer, it is preferable to use the organic peroxide polymerization initiator. Examples of such an organic peroxide-based polymerization initiator include benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, and tert-
Butyl peroxy benzoate etc. are mentioned.

Thus, the 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.
When it is less than 0 ⁴ , not only the decrease in cohesive force after transfer of the plasticizer is large, but also the initial adhesive force may be small.

Next, the acrylic block polymer (b) will be described. The acrylic block polymer (b) is produced by a production method including a preparation step, a first polymerization step, an addition step and a second polymerization step. The preparation process consists of polyvalent mercaptan and 2
It is a step of preparing a first mixture containing a first α, β-unsaturated monomer capable of forming a high glass transition point polymer having a glass transition point of 73 K or higher. The first polymerization step starts with the mercapto group of the polyvalent mercaptan as the first step.
Is a step of performing a radical polymerization of the α, β-unsaturated monomer to obtain a reaction mixture. The addition step is a reaction in which a monomer mixture containing a (meth) acrylic acid alkyl ester monomer capable of forming a polymer incompatible with the high glass transition point type polymer is obtained in the first polymerization step. Second in addition to the mixture
This is a step of obtaining a mixture. The second polymerization step is a step of radically polymerizing the monomers contained in the second mixture.

The polyvalent mercaptan used in the present invention is a compound having two or more mercapto groups per molecule, and the number of mercapto groups per molecule is 2,
The mercaptans of 3, ... Are referred to as divalent mercaptans, trivalent mercaptans ,. Examples of the polyvalent mercaptan include ethylene glycol and 1,4
A diester of a diol such as butanediol and a carboxyl group-containing mercaptan; a compound having three or more hydroxyl groups such as trimethylolpropane, pentaerythritol, dipentaerythritol and a polyester compound of a carboxyl group-containing mercaptan; a mercapto such as trithioglycerin A compound having 3 or more groups; 2-
Triazine polyvalent thiols such as di-n-butylamino-4,6-dimercapto-S-triazine and 2,4,6-trimercapto-S-triazine; hydrogen sulfide is added to a plurality of epoxy groups of the polyvalent epoxy compound. A compound obtained by adding a plurality of mercapto groups; an ester compound obtained by esterifying a plurality of carboxyl groups of a polyvalent carboxylic acid and mercaptoethanol, and the like, and any one of them alone, or, Two or more can be used together. Here, the carboxyl group-containing mercaptans means one mercapto group such as thioglycolic acid, mercaptopropionic acid, and thiosalicylic acid and 1
A compound having one carboxyl group.

The polyvalent mercaptan used in the present invention is
From the viewpoint of efficiently producing a block polymer, and from the viewpoint of improving the performance of the resulting polymer by introducing a structure radially extending from the same center, preferably 2 to
Compounds having 10 mercapto groups (ie 2 to
A monovalent mercaptan), more preferably a compound having 3 to 6 mercapto groups (that is, a trivalent to hexavalent mercaptan). A mercaptan having only one mercapto group does not give a structure in which the polymer portion extends radially. A mercaptan having more than 10 mercapto groups does not have a structure extending radially from the same center, and thus the desired physical properties may not be exhibited.

The polyvalent mercaptan is a mercaptan having a valence of 3 to 6, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropionate, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, At least one compound selected from dipentaerythritol hexakisthioglycolate and dipentaerythritol hexakisthiopropionate is preferable. The reason for this is that the block polymer that is formed has a star-shaped structure radially from the same center, so the effect of entanglement between polymer chains (for example, high cohesive force) and the morphological change of the phase separation structure can be expected. Because there is.

Acrylic block polymer according to the present invention
In (b), the plurality of radially extending polymer moieties have two or more different compositions. This composition difference, when derived from a homopolymer, the difference in the monomer units constituting the polymer, the number average molecular weight of the polymer, or when derived from a copolymer, the monomer It can be obtained by the difference in the units, the number average molecular weight of the polymer, the ratio of the monomer units, and the like. The polymer portion usually has a number average molecular weight of 1,000 to 5
0,000, preferably 5,000 to 200,000
It is 0, more preferably 10,000 to 100,000. If the number average molecular weight of the polymer portion is less than the above range, it may not be possible to introduce properties based on the polymer portion into this block polymer, and if it exceeds the above range, the viscosity at the time of production becomes high, which is preferable in terms of productivity. There is a possibility that there is no.

In the acrylic block polymer (b),
The combination of polymer moieties having different compositions depends on the performance (or application) required of the block polymer. Basically, the combination of polymer parts is a combination of polymer parts derived from polymers having different glass transition points (Tg). By combining the polymer moieties derived from the polymers having different Tg's, the polymer moieties derived from the polymer having a low Tg form a continuous phase. As an example of such a block polymer, polymethylmethacrylate (PMMA), Tg
Polyacrylate (PBA) as low polymer
The combination of In the case of this combination, P
The number average molecular weight of MMA is preferably 5,000 to 200,000, and the number average molecular weight of PBA is 10,000 to 15
10,000 is preferable, and the weight ratio of PMMA / PBA is 1
The range of 0/90 to 90/10 is preferable. Outside of these ranges, sufficient performance may not be obtained. In order for the polymer portion derived from the polymer having a low Tg to form a continuous phase, the proportion of the polymer having a low Tg should be increased,
Alternatively, it is necessary to reduce the melt viscosity of a polymer having a low Tg.

In the acrylic block polymer (b) of the present invention, the polyvalent methacrylate moiety is a residue of a mercaptan having a valence of 3 to 6, and a plurality of polymer moieties have two different compositions. I):

[0035]

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Polymers of the formula: are possible. In the above formula (I), polymer moieties having different compositions from PA and PB, for example, the following combinations are possible. PA: PB PMMA: PBA PSt: P (BA / AA) PMMA: P (BA / AA) In the above formula (I), the following formula:

[0037]

Embedded image

The portion represented by is a trivalent to hexavalent mercaptan residue. In the above formula (I), n + m is 3 or more and is equal to or less than the valence of the residue of the mercaptan, and n is 0.
1 or more, preferably 0.5 or more, m is 0.1 or more,
The number is preferably 0.5 or more. If n or m is less than the above value, the desired sufficient performance may not be obtained.

The first α, β-unsaturated monomer is 273K
At least one monomer having at least one high glass transition point polymer selected from the group consisting of homopolymers and copolymers having a glass transition point of 300K or higher is preferable. When the glass transition point of the high glass transition point type polymer is below the above range, the pressure-sensitive adhesive does not have sufficient cohesive force, and the cohesive force is greatly reduced due to the transfer of the plasticizer. The first α, β-unsaturated monomer is, for example, at least one selected from the group consisting of styrene, vinyl acetate, acrylonitrile, methacrylonitrile and methyl methacrylate in an amount of 5 to 40% by weight, preferably 10 to 10. 30% by weight, the balance being the above-mentioned (meth) acrylic acid alkyl ester monomer, reactive functional group-containing α, β-
It is at least one selected from the group consisting of unsaturated monomers and copolymerizable α, β-unsaturated monomers.

A first mixture containing polyvalent mercaptan and a first α, β-unsaturated monomer is provided. The first mixture is
If necessary, for example, aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; alicyclic hydrocarbons such as cyclohexane; aliphatic hydrocarbons such as hexane and pentane. It may contain an organic solvent. The organic solvent may be a single solvent or a mixed solvent.

The number average molecular weight of the acrylic block polymer (b) is 2,000 to 1,000,000, preferably 10,000 to 400,000, more preferably 20,
000 to 200,000. If the number average molecular weight is less than the above range, the properties as a block polymer may not be exhibited, and if the number average molecular weight exceeds the above range, the viscosity may be high and the handleability may be poor.

The acrylic block polymer (b) is produced by a first polymerization step and a second polymerization step which will be described later.
It is possible to have a plurality of polymer moieties having different compositions described above, and to have a plurality of polymer moieties having different compositions of 3 or more by repeating the second polymerization step twice or more. is there. In the first polymerization step, the first α, with the mercapto group of the polyvalent mercaptan as the starting point,
Radical polymerization of β-unsaturated monomer is performed. By this radical polymerization, in each molecule of the polyvalent mercaptan, a product in which one end of a polymer portion having one composition is bonded to the sulfur residue of one or more mercapto groups is obtained. This product has unreacted mercapto groups. In order to efficiently bind one end of the polymer portion to the sulfur residue, it is preferable not to add an unnecessary polymerization initiator to the polymerization system.

In the adding step, the monomer mixture is added to the reaction mixture obtained by the radical polymerization performed previously to obtain the second mixture. This monomer mixture is capable of forming a polymer that is incompatible with the high glass transition type polymer, and (meth)
Includes alkyl acrylate monomer. here,
“Not compatible” has the meaning described in the description of the acrylic graft polymer (a).

The monomer mixture used in the addition step is
A (meth) acrylic acid alkyl ester monomer is contained as an essential component, and if necessary, a reactive functional group-containing α, β-
An unsaturated monomer may be further included. The monomer mixture, regardless of whether it further contains a reactive functional group-containing α, β-unsaturated monomer, is an α, β-unsaturated monomer copolymerizable with these monomers. Can be further included.

(Meth) acrylic acid alkyl ester monomer, reactive functional group-containing α, β-unsaturated monomer, and
The type and amount of the copolymerizable α, β-unsaturated monomer are
Each is as described in the description of the acrylic graft polymer (a). Acrylic block polymer (b)
The composition and amount of the monomer mixture used for obtaining the above are also as described in the description of the acrylic graft polymer (a).

In the second polymerization step, radical polymerization of the monomers contained in the second mixture is carried out. If necessary, the unreacted monomer component can be removed from the reaction mixture containing the product of the radical polymerization previously carried out, or
Unreacted monomer components may be left without being removed and used in the radical polymerization to be performed next. Subsequent radical polymerization is carried out starting from all or part of the remaining mercapto groups of the polyvalent mercaptan. A product is obtained in which one end of the polymer moiety having another composition is bonded to the sulfur residue of the starting mercapto group. This product may have unreacted mercapto groups.
In this case, the second polymerization step is repeated twice to introduce a polymer portion having a third different composition, and the second polymerization step is repeated three times to obtain the third and fourth
The polymer moieties having different compositions can be introduced, and the polymer moieties having different compositions can be introduced each time the number of repetitions of the second polymerization step is increased.

The first and second polymerization steps for preparing the acrylic block polymer (b) can be carried out by the usual radical polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization. In order to obtain an inexpensive polymer, a bulk polymerization method containing no excess volatile component is preferable. The polymerization temperature is preferably 30 to 200 ° C., more preferably 100 to 1 which enables stable bulk polymerization without using a polymerization initiator.
50 ° C.

Radical polymerization initiators (eg, 2, ordinarily used in polymerization for producing the acrylic block polymer (b))
2'-azobisisobutyronitrile, 2,2'-azobiscyclohexanecarbonitrile and other azo-based polymerization initiators; benzoyl peroxide and other peroxide-based polymerization initiators, etc.) can be used. Usually, 1/3 or less of polyvalent mercaptan, preferably 1/10 or less, more preferably not used. When the polymerization initiator is used in a larger amount than the above ratio, a large amount of the polymer extended from the polymerization initiator is generated in addition to the polymer portion extended from the polyvalent mercaptan which gives the block polymer, and the production efficiency of the block polymer is increased. And the stability of bulk polymerization, which is an industrially inexpensive manufacturing method, deteriorates, a runaway reaction occurs, and in the worst case, there is a risk of explosion.

As the procedure for producing the acrylic block polymer (b), radical polymerization of the first α, β-unsaturated monomer is carried out starting from the mercapto group of the polyvalent mercaptan, and the polymerization rate is 50. % Or more, preferably 80% or more, an acrylic block polymer (b) can be obtained by adding and polymerizing a monomer mixture containing a (meth) acrylic acid alkyl ester monomer. . The polymerization rate of the radical polymerization carried out first is 50% or more because the properties of the polymer forming the block even if the next polymerization is carried out without removing the unsaturated monomer remaining after the polymerization. Is to be as different as possible. Therefore, it is possible to volatilize and remove the remaining unsaturated monomer after the first polymerization step. Further, if each radical polymerization is terminated by addition of a polymerization inhibitor, it is possible to prevent the tip of the produced polymer portion from being connected to a polymer portion having a different composition by the subsequent radical polymerization.

By carrying out the polymerization in multiple stages as described above, the acrylic block polymer (b) composed of a combination of three or more kinds of polymers can be obtained. 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) or the acrylic block polymer (b) can be dissolved and / or dispersed. , For example, aromatic hydrocarbons such as toluene and xylene, and esters such as ethyl acetate and butyl acetate,
It is a single solvent or a mixed solvent of two or more selected from the group consisting of alicyclic hydrocarbons such as cyclohexane, ketones such as acetone and methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and pentane. The amount of organic solvent is
For example, 10 parts to 100 parts by weight of the acrylic polymer
It is 0 to 400 parts by weight, preferably 150 to 350 parts by weight. If it is less than the above range, the viscosity becomes too high, which may cause difficulty in coating work, and if it exceeds the above range, the viscosity may be too low and coating may not be possible.

The adhesive composition of the present invention comprises an acrylic graft polymer (a) or an acrylic block polymer (b).
However, when it is prepared using a monomer mixture containing a reactive functional group-containing α, β-unsaturated monomer, a crosslinking agent can be further included. The cross-linking agent has at least two functional groups capable of reacting with the reactive functional groups of the acrylic polymer per molecule. Examples of the crosslinking agent used in the present invention include a polyfunctional epoxy compound, a polyfunctional melamine compound, a polyfunctional isocyanate compound, a metal-based crosslinking agent, and an aziridine compound. In particular, a polyfunctional isocyanate compound is preferable in the reaction with 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 so on,
They may be used alone or in combination of two or more.

The polyfunctional melamine compound is
There is no particular limitation as long as it is a compound having two or more of methyl roll group, alkoxymethyl group and imino group,
For example, hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentyloxymethyl melamine, etc. are mentioned, and they are used individually or in combination of two or more.

The polyfunctional isocyanate compound is 1
There is no particular limitation as long as it is a compound having two or more isocyanate groups per molecule, and examples thereof include tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, xylylene diisocyanate, and metaxylylene diisocyanate. Isocyanate, 1,5-naphthalene diisocyanate,
Isocyanate compounds such as hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate and isophorone diisocyanate; Sumidule N (Sumitomo Bayer Urethane Co.)
Such as burette polyisocyanate compound; polyisocyanate compound having isocyanurate ring such as Desmodur IL, HL (manufactured by Bayer AG), Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.); Sumidule L (Sumitomo Bayer) Examples thereof include adduct polyisocyanate compounds such as Urethane Co., Ltd., and adduct polyisocyanate compounds such as Coronate L (manufactured by Nippon Polyurethane Co.). These may be used alone or in combination of two or more. It is also possible to use a blocked isocyanate in which the isocyanate group of these polyvalent isocyanate compounds is inactivated by reacting with a masking agent having active hydrogen.

Examples of the metal-based cross-linking agent include metals such as aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, zirconium, chromium and tin, and acetylacetone, methyl acetoacetate and acetoacetate. Examples thereof include metal chelate compounds coordinated with ethyl acetate, ethyl lactate, methyl salicylate and the like. These may be used alone or in combination of two or more.

Examples of the aziridine compound include N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate and bisisophthaloyl-1. −
(2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-diphenylethane-
4,4′-bis (1-aziridinecarboxamide) and the like can be mentioned. These may be used alone or in combination of two or more.

The amount of the cross-linking agent used is, for example, 0.
It is 1 to 10 parts by weight, preferably 0.5 to 5 parts by weight.
If the amount of the cross-linking agent is less than 0.1 part by weight, the cross-linking points will be insufficient, so that the cross-linking density may be insufficient and the cohesive force may be insufficient. If it exceeds 10 parts by weight, the cross-linking density will be high. The adhesive strength may be reduced due to excessive passage.

The pressure-sensitive adhesive composition of the present invention may contain a tackifier commonly used in pressure-sensitive adhesives, if necessary. As the tackifier, (polymerized) rosin type, (polymerized) rosin ester type, terpene type, terpene phenol type, coumarone type, coumarone indene type, styrene resin type, xylene resin type, phenol resin type, petroleum resin type, etc. Examples of the tackifier include These can be used alone or in combination of two or more. The amount of tackifier is, for example, 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the acrylic polymer (a) or (b). If it is less than the above range, the adhesiveness to an adherend may not be improved, and if it exceeds the above range, tack may be reduced and adhesive strength may be lowered.

The pressure-sensitive adhesive composition of the present invention contains fillers, pigments, diluents, antioxidants, anti-aging agents, ordinarily used for pressure-sensitive adhesives, whether or not they contain tackifiers. It may contain at least one additive selected from the group consisting of an ultraviolet absorber and an ultraviolet stabilizer. The pressure-sensitive adhesive composition of the present invention is used, for example, for producing a pressure-sensitive adhesive product by the method described below. [Adhesive product] The adhesive product of the present invention comprises a pressure-sensitive adhesive layer for soft vinyl chloride formed using the composition for pressure-sensitive adhesive of the present invention, and is applied to a soft polyvinyl chloride molded product.

The soft vinyl chloride adhesive layer is formed, for example, as follows. (A) An acrylic graft polymer (a) and an organic solvent in which the acrylic graft polymer (a) is dissolved and / or dispersed are contained in the composition for pressure-sensitive adhesive of the present invention, and the composition is applied to an object to be coated. The pressure-sensitive adhesive layer for soft vinyl chloride is formed by a production method including a crosslinking step of drying and crosslinking. (B) An acrylic block polymer (b) and an organic solvent in which the acrylic block polymer (b) is dissolved and / or dispersed are applied to a pressure-sensitive adhesive composition of the present invention, which is applied to an object to be coated. The pressure-sensitive adhesive layer for soft vinyl chloride is formed by a production method including a crosslinking step of drying and crosslinking.

Each monomer mixture used in the polymerization step for producing the acrylic graft polymer (a) and the acrylic block polymer (b) is a reactive functional group-containing α, β-unsaturated monomer. May be further included. When the monomer mixture contains a reactive functional group-containing α, β-unsaturated monomer, the pressure-sensitive adhesive composition further comprises a crosslinking agent having at least two functional groups capable of reacting with the reactive functional group. May be included.

In the crosslinking step, the organic solvent is removed from the pressure-sensitive adhesive composition by applying the pressure-sensitive adhesive composition to the article to be coated and drying it, and the acrylic graft polymer (a) or the acrylic block polymer is then added. Crosslink (b). As the article to be coated, for example, a separator, a support, a base material, etc. described later are appropriately used.

Crosslinking of the acrylic graft polymer (a) or the acrylic block polymer (b) accelerates the reaction, for example, by room temperature crosslinking at room temperature for one week or more, or in a thermostatic chamber at 40 to 50 ° C. It is carried out by high temperature accelerated crosslinking. When the acrylic graft polymer (a) or the acrylic block polymer (b) is prepared using a monomer mixture containing a reactive functional group-containing α, β-unsaturated monomer, the acrylic polymer is It is crosslinked by a reaction with a crosslinking agent having at least two functional groups capable of reacting with the reactive functional group of the united product. The cross-linking agent used here is the same as the cross-linking agent used in the pressure-sensitive adhesive composition. The cross-linking conditions may be appropriately set depending on the cross-linking agent used.

The adhesive product of the present invention may further include a separator attached to one or both sides of the soft vinyl chloride adhesive layer. The adhesive product of the present invention comprises two adhesive layers for soft PVC, and a support sandwiched between the adhesive layers for soft PVC and one surface of the adhesive layer for soft PVC opposite to the support. It may further include a separator attached to.

The adhesive product of the present invention may further include a separator attached to one side of the soft vinyl chloride adhesive layer and a base material attached to the other side of the soft vinyl chloride adhesive layer. The base material is, for example, a soft polyvinyl chloride base material. Examples of the separator used in the present invention include a paper base material whose surface is directly release-treated 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 base material, and a polyester. -A plastic film such as polyethylene or polypropylene is used.

The adhesive product of the present invention is, for example, an adhesive sheet, an adhesive tape, an adhesive label, a double-sided tape, etc. for soft PVC; or a soft PVC adhesive sheet, a soft PVC adhesive tape, a soft PVC adhesive label and the like. The adhesive product of the present invention is produced by the following method, but the production method is not limited. On one surface of the separator, a pressure-sensitive adhesive composition of the present invention, which is coated with at least an acrylic polymer (a) or (b) and a cross-linking agent and an organic solvent, after drying,
The pressure-sensitive adhesive layer formed on the surface of the separator is superposed on one surface of another separator, a base material described later or a support described later, and pressed (for example, at a pressure of 1 to 5 kg / cm ² ) to be transferred. It is also possible to superimpose the pressure-sensitive adhesive layers formed on the surfaces of the two separators on both sides of the support described later and apply pressure in the same manner to transfer them. On one surface or both surfaces of the support, the composition for pressure-sensitive adhesive of the present invention, at least the acrylic polymer (a) or
(b) Apply a coating containing a crosslinking agent and an organic solvent, dry,
A separator is attached so as to cover the obtained pressure-sensitive adhesive layer.

The dry thickness of the pressure-sensitive adhesive layer is, for example, 10 to 1
It is 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 pressure-sensitive adhesive product of the present invention are applied to a soft polyvinyl chloride molded article. The soft polyvinyl chloride molded article is an adherend to which a pressure-sensitive adhesive layer is attached, and can be, for example, a sheet, a tape, a wallpaper, a foam (foam) or the like.

In the adhesive product of the present invention, the support may be a soft polyvinyl chloride molded product.

[0069]

[Function] In the acrylic graft polymer (a) or the acrylic block polymer (b) of the pressure-sensitive adhesive composition of the present invention,
The high glass transition point polymer portion is dispersed in the polymer portion of the monomer mixture containing the (meth) acrylic acid alkyl ester monomer, and the high glass transition point polymer portion and It is chemically bonded to the polymer portion of the monomer mixture. This means that a system in which a polymer of a monomer mixture containing a (meth) acrylic acid alkyl ester monomer and a high glass transition type polymer are simply blended tends to separate in a solution state. This can be verified from the fact that the system of the present invention does not show this tendency. The high glass transition type polymer part has a micro-domain structure with respect to the polymer part of the monomer mixture containing the (meth) acrylic acid alkyl ester monomer, and the physical property of the polymer part is adhesive. Since it functions as a cross-linking agent, the pressure-sensitive adhesive composition of the present invention forms a pressure-sensitive adhesive exhibiting high cohesive force without impairing the tackiness even when applied to a soft polyvinyl chloride molded article.

[0070]

EXAMPLE FIG. 1 is a sectional view of an example of the adhesive product of the present invention. This adhesive product is a double-sided adhesive tape 5,
It has a support 1, a soft vinyl chloride adhesive layer 2, and a separator 3. The pressure-sensitive adhesive layer 2 for soft vinyl chloride is an acrylic cross-linked copolymer (acrylic graft polymer (a) or acrylic block) produced by a production method including a step of drying and crosslinking the pressure-sensitive adhesive composition of the present invention. The polymer (b) is crosslinked) as a main component and is formed on both sides of the support 1. The separator 3 is, for example, a release paper, and is attached to this surface so as to cover one surface of the soft vinyl chloride adhesive layer 2. One surface of the pressure-sensitive adhesive layer 2 is the surface opposite to the one surface attached to the support 1.

The support is, for example, conventionally known paper, plastic film, foam sheet, non-woven fabric or the like. In the adhesive product of the present invention, the support can be a soft polyvinyl chloride molded product (eg, film, sheet, tape, wallpaper). FIG. 2 shows another example of the adhesive product of the present invention.
It is sectional drawing of an Example. This pressure-sensitive adhesive product is a coreless double-sided pressure-sensitive adhesive tape (double-sided pressure-sensitive adhesive tape without a support) 6, and has a soft vinyl chloride pressure-sensitive adhesive layer 2 and a separator 3.

The pressure-sensitive adhesive layer 2 for soft vinyl chloride is an acrylic cross-linked copolymer (acrylic graft polymer (a) or prepared by a production method including a step of drying and crosslinking the pressure-sensitive adhesive composition of the present invention. Acrylic block polymer (b) is cross-linked) as a main component. The separator 3 is
For example, it is a release paper, and is attached to both sides of the soft vinyl chloride 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 vinyl chloride, a separator 3, and a substrate 4. The pressure-sensitive adhesive layer 2 for soft vinyl chloride is an acrylic cross-linked copolymer (acrylic graft polymer (a) or acrylic block) produced by a production method including a step of drying and crosslinking the pressure-sensitive adhesive composition of the present invention. (Crosslinked polymer (b)) is included as a main agent. The separator 3 is, for example, release paper, and is attached to one surface of the soft vinyl chloride adhesive layer 2 so as to cover the one surface. 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 a soft vinyl chloride adhesive layer 2, a separator 3, and a substrate 7. The pressure-sensitive adhesive layer 2 for soft vinyl chloride is an acrylic cross-linked copolymer (acrylic graft polymer (a) or acrylic block) produced by a production method including a step of drying and crosslinking the pressure-sensitive adhesive composition of the present invention. (Crosslinked polymer (b)) is included as a main agent. The separator 3 is, for example, release paper, and is attached to one surface of the soft vinyl chloride adhesive layer 2 so as to cover the one surface. The base material 7 is, for example, amimi 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 Adhesive Composition] -Example A1-210 parts of ethyl acetate and 100 parts of polystyrene (Styron 666R manufactured by Asahi Kasei Corporation) were used as a thermometer, a stirrer, an inert gas introduction tube, a reflux condenser and a dropping funnel. A 4-neck flask equipped with was charged into the flask, and polystyrene was dissolved in ethyl acetate. Then, in this flask, 379.6 parts of butyl acrylate, 20 parts of acrylic acid and 2 parts of acrylic acid were added.
133.3 parts of 400 parts of a monomer mixture with 0.4 parts of hydroxyethyl were charged. While stirring the contents of the flask under a nitrogen stream and maintaining the temperature at 80 ° C., 0.32 parts of Niper BMT-K40 (organic peroxide manufactured by NOF CORPORATION) as a polymerization initiator was added to the contents for polymerization. Let it start. Ten minutes after the initiation of polymerization, the rest of the monomer mixture (266.7 parts), 76 parts of toluene, 76 parts of ethyl acetate, and 0.8 parts of Niper BMT-K40 (organic peroxide manufactured by NOF Corporation) were added. After dripping continuously for 1.5 hours, 76 parts of ethyl acetate and 490 parts of toluene and 2,
1.2 parts of 2'-azobis (2-methylbutyronitrile) (manufactured by Japan Hydrazine Industry Co., Ltd., hereinafter abbreviated as ABNE) was added and reacted at 85 ° C for 5 hours to give a solid content of 34.5%.
Viscosity 3670 cps (25 ° C, B-type viscometer, the same below)
A solution of the acrylic copolymer of was obtained.

-Examples A2 to A10-The procedure of Example A1 was repeated except that the reaction raw materials and / or the reaction conditions were changed as shown in Tables 1 and 3, and the solid content, viscosity, and A solution of an acrylic copolymer having a weight average molecular weight was obtained. -Comparative Examples A1 to A8- The solid content, viscosity and weight shown in Tables 3 and 4 were repeated by repeating the procedure of Example A1 except that the reaction raw materials and / or the reaction conditions were changed as shown in Tables 1 to 4. A solution of an acrylic copolymer having an average molecular weight was obtained.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

-Example A11- 200 parts of styrene and 1.0 part of pentaerythritol tetrakisthioglycolate (PETG) were used as a thermometer, a stirrer, and Maxblend blade (Sumitomo Heavy Industries, Ltd.),
A 2-liter four-necked flask equipped with an inert gas introduction tube, a reflux condenser and a dropping funnel was charged, and polymerization was carried out at 140 ° C. under a nitrogen atmosphere. After 3 hours, 760 parts of butyl acrylate and 40 parts of acrylic acid were added all at once. After a while, it was found that when the internal temperature increased, the reaction mixture became cloudy and the second-stage polymerization was started. The polymerization rate after reacting for 5 hours at the monomer reflux temperature was 99.4%. The residual monomer was removed under reduced pressure, and 1300 parts of toluene was added to the reaction mixture to dissolve it, and the solid content was 36.4.
%, A solution of an acrylic copolymer having a viscosity of 17200 cps was obtained.

-Examples A12 to A14 and Comparative Example A9
The procedure of Example A11 was repeated, except that the reaction raw materials and / or the reaction conditions were changed as shown in Table 5, to give a solution of the acrylic copolymer having the solid content, the viscosity and the weight average molecular weight shown in Table 5. Obtained.

[0083]

[Table 5]

Example B1-Coronate L55E (polyisocyanate compound manufactured by Nippon Polyurethane Industry Co., Ltd .: solid content 55) relative to the solution of the acrylic copolymer obtained in Example A1 (solid content 100 parts)
%) Was mixed to prepare an adhesive composition. -Comparative Example B1- 1.25 parts of Coronate L55E was mixed with the acrylic copolymer solution (solid content 100 parts) obtained in Comparative Example A1 to prepare a pressure-sensitive adhesive composition.

-Examples B2-B18 and Comparative Examples B2-
The amounts of the B10- acrylic copolymer solution and the cross-linking agent are shown in Tables 6 to 8.
The operation of Example B1 was repeated except that the pressure-sensitive adhesive composition was changed as shown in to prepare a pressure-sensitive adhesive composition. -Example C1-After coating the pressure-sensitive adhesive composition obtained in Example B1 on one side of a release paper (Fujimori Kogyo Co., Ltd .: 70K-818T / EF) so that the thickness after drying would be 50 μm, It was dried at 100 ° C. for 2 minutes and aged at 23 ° C. for 7 days. Then 5
A soft polyvinyl chloride sheet (made by Okamoto Co., Ltd.) having a thickness of 0 μm is superposed on one side and pressed, and the pressure-sensitive adhesive composition is transferred to one side of the soft polyvinyl chloride sheet to give a soft vinyl chloride adhesive sheet (with release paper). Obtained.

Comparative Example C1-The pressure-sensitive adhesive composition obtained in Comparative Example B1 was coated on one side of a release paper (Fujimori Kogyo Co., Ltd .: 70K-818T / EF) so that the thickness after drying would be 50 μm. After that, it was dried at 100 ° C. for 2 minutes and cured at 23 ° C. for 7 days. Then 5
A soft polyvinyl chloride sheet (made by Okamoto Co., Ltd.) having a thickness of 0 μm is superposed on one side and pressed, and the pressure-sensitive adhesive composition is transferred to one side of the soft polyvinyl chloride sheet to give a soft vinyl chloride adhesive sheet (with release paper). Obtained.

-Examples C2-C18 and Comparative Examples C2-
C10- The procedure of Example C1 was repeated except that the pressure-sensitive adhesive composition was changed as shown in Tables 6 to 8, to produce a soft vinyl chloride pressure-sensitive adhesive sheet. -Example D1-The pressure-sensitive adhesive composition obtained in Example B1 was coated on each one surface of two release papers (70K-818T / EF manufactured by Fujimori Kogyo Co., Ltd.) so that the thickness after drying was 75 μm. Engineered, 100
After being dried at ℃ for 3 minutes, the pressure-sensitive adhesive composition coated surfaces of the two release papers are overlapped on both sides of the non-woven fabric and pressed, and the pressure-sensitive adhesive composition is transferred to both sides of the non-woven fabric to obtain a thickness of 150 μm on both sides. A tape (with double-sided release paper) was prepared.

-Comparative Example D1- The pressure-sensitive adhesive composition obtained in Comparative Example B1 was dried on one surface of each of two release papers (Fujimori Kogyo Co., Ltd .: 70K-818T / EF) to have a thickness of 75 μm. To apply 100
After being dried at ℃ for 3 minutes, the pressure-sensitive adhesive composition coated surfaces of the two release papers are overlapped on both sides of the non-woven fabric and pressed, and the pressure-sensitive adhesive composition is transferred to both sides of the non-woven fabric to obtain a thickness of 150 μm on both sides. A tape (with double-sided release paper) was prepared.

-Examples D2-D18 and Comparative Examples D2-
D10- The double-sided tape was produced by repeating the operation of Example D1 except that the pressure-sensitive adhesive composition was changed as shown in Tables 6 to 8. -Comparative Example D11- A commercially available double-sided tape for soft PVC (trade name: Double Tack Tape # 577 manufactured by Sekisui Chemical Co., Ltd.) was prepared for comparison.

-Comparative Example D12- A commercially available double-sided tape for soft PVC (double-sided adhesive tape No. 501M, trade name, manufactured by Nitto Denki Kogyo Co., Ltd.) was prepared for comparison. -Comparative Example D13- A commercially available double-sided tape for soft PVC (trade name double-sided adhesive tape No. 5000CX manufactured by Nitto Denki Kogyo Co., Ltd.) was prepared for comparison.

In the table, TETRAD-C is 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane manufactured by Mitsubishi Gas Chemical Co., Inc. With respect to the soft vinyl chloride pressure-sensitive adhesive sheets and double-sided tapes obtained in Examples and Comparative Examples, the holding force and the adhesive force were measured according to JIS-Z0237 (1991), and the results are shown in Tables 6-8.

The holding power is a stainless steel plate (SUS30
The adhesive sheet of 20 mm × 20 mm is attached to 4), and 20 minutes after the attachment, the temperature is kept at 80 ° C., and after 20 minutes, a load of 1 kg is applied to drop the sheet, or
The amount of deviation measured 24 hours after applying the load is shown. The adhesive strength of the pressure-sensitive adhesive sheet is shown as an initial value and a value after heating is promoted. The initial value is that a 25 mm width adhesive sheet is attached to an aluminum plate (JI
SA1050P: thickness 1 mm) was reciprocated once with a 2 kg rubber roller, and after 25 minutes, the strength when peeled in the 180 ° direction at a speed of 300 mm / min was measured. The value after heating acceleration is as follows. The pressure-sensitive adhesive sheet is 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 width of 20 mm, and then cut into an aluminum plate.
A rubber roller of kg was reciprocated 3 times to bond them, and after 24 hours, the strength when peeled in a 180 degree direction at a speed of 300 mm / min was measured.

The adhesive strength of the double-sided tape was shown by the initial value and the value after heating was accelerated. The initial value is 23 ° C., 65% RH atmosphere, PET film that has been subjected to corona discharge treatment is lined from one side of the double-sided tape, the double-sided tape is cut into a width of 20 mm, and then soft salt with a thickness of 2 mm is used. Bisheet (Okamoto Co., Ltd., # 480, plasticizer 50 phr, back side fixed to aluminum plate with commercial double-sided adhesive tape)
2kg rubber roller back and forth 3 times
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 heating acceleration is a soft vinyl sheet with a thickness of 2 mm, which is a double-sided tape lined with a PET film that has been subjected to a corona discharge treatment and cut into a width of 20 mm (Okamoto Co., Ltd., # 480, plasticizer 50 phr, the back side is commercially available Aluminum plate fixed with double-sided adhesive tape)
2kg of rubber roller back and forth 3 times to stick together, 8
Leave in 0 ℃ atmosphere for 3 days, then 23 ℃, 65% R
The strength at the time of peeling in the direction of 180 degrees at a speed of 300 mm / min after standing for 2 hours in the atmosphere of H was measured.

[0094]

[Table 6]

[0095]

[Table 7]

[0096]

[Table 8]

As shown in Tables 1 to 8, the examples of the present invention are suitable for a single-sided pressure-sensitive adhesive sheet or double-sided depending on the molecular weight of the obtained polymer (acrylic graft polymer or acrylic block polymer). There are some suitable for adhesive tapes, but it has excellent initial adhesive strength and suppresses the decrease in cohesive strength even when the plasticizer migrates from soft PVC due to accelerated heating, and the adhesive strength is considerably higher than the comparative example. You can see that it is maintained at.

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) Methyl methacrylate: 378 (K) Vinyl acetate: 305 (K) Acrylonitrile: 398 (K) Styrene: 373 (K)

[0099]

[Equation 1]

[0100]

The pressure-sensitive adhesive composition of the present invention comprises an acrylic graft polymer (a) or an acrylic block polymer.
Since it contains (b) and an organic solvent, it has an excellent balance of cohesive strength and adhesive strength, it is less likely to cause a decrease in cohesive strength due to migration of the plasticizer, and it has excellent shelf life, which is practically important for adhesive products for soft PVC. It can be used to make an adhesive layer for soft PVC.

The pressure-sensitive adhesive composition of the present invention has a functional group which reacts with a reactive functional group-containing α, β-unsaturated monomer when the monomer mixture further contains these reactive functional groups. Further, it has an advantage that the cohesive force can be arbitrarily controlled by using a crosslinking agent. The pressure-sensitive adhesive composition of the present invention has at least two functional groups capable of reacting with a reactive functional group when the monomer mixture further contains a reactive functional group-containing α, β-unsaturated monomer. When a cross-linking agent is further included, it further has an advantage that a sufficient amount of the cross-linking agent can be obtained.

Since the pressure-sensitive adhesive product of the present invention has the pressure-sensitive adhesive layer for soft vinyl chloride formed by using the pressure-sensitive adhesive composition of the present invention, it has a cohesive force when applied to a soft polyvinyl chloride molded article. It has an excellent balance between the adhesive strength and the adhesive strength, is less likely to cause a decrease in the cohesive strength due to the migration of the plasticizer, and has an excellent shelf life, which is practically important for soft PVC adhesive products.

[Brief description of drawings]

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

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

[Explanation of symbols]

 1 Support 2 Adhesive Layer 3 Separator 4 Base Material 5 Double-sided Adhesive Tape 6 Coreless Double-sided Adhesive Tape

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Meiwa Baba 5-8 Nishimitabicho Suita City Osaka Prefecture Nihon Shokubai Suita Factory (72) Inventor Masatoshi Yoshida 5-8 Nishiomitabicho Suita City Osaka Prefecture No. 52, Japan Catalytic Polymer Research Laboratory (72) Inventor Nobuhiro Kobayashi No. 5-8 Nishimitabicho, Suita City, Osaka Prefecture

Claims (6)

[Claims] 1. A pressure-sensitive adhesive composition for producing a soft polyvinyl chloride pressure-sensitive adhesive applied to a soft polyvinyl chloride molded article, comprising a monomer mixture containing a (meth) acrylic acid alkyl ester monomer. , Not compatible with the polymer of the monomer mixture 2
An acrylic graft polymer produced by a production method including a polymerization step of copolymerizing in the presence of a high glass transition type polymer having a glass transition point of 73 K or more, and the acrylic graft polymer is dissolved and / or A composition for pressure-sensitive adhesive, comprising: a dispersed organic solvent. 2. A pressure-sensitive adhesive composition for producing a soft polyvinyl chloride pressure-sensitive adhesive applied to a soft polyvinyl chloride molded article, which is a high glass transition point type having polyvalent mercaptan and a glass transition point of 273 K or more. First α, β- capable of forming a polymer
A preparatory step of preparing a first mixture containing an unsaturated monomer, and a reaction mixture by radical polymerization of the first α, β-unsaturated monomer starting from the mercapto group of the polyvalent mercaptan. And a monomer mixture containing a (meth) acrylic acid alkyl ester monomer capable of forming a polymer incompatible with the high glass transition point type polymer, in the reaction mixture. In addition, an acrylic block polymer produced by a production method including an addition step of obtaining a second mixture and a second polymerization step of radically polymerizing the monomer contained in the second mixture, and the acrylic block polymer. An adhesive composition comprising an organic solvent in which a block polymer is dissolved and / or dispersed. 3. The monomer mixture is a reactive functional group-containing α,
The pressure-sensitive adhesive composition according to claim 1, further comprising a β-unsaturated monomer. 4. The pressure-sensitive adhesive composition according to claim 3, further comprising a crosslinking agent having at least two functional groups capable of reacting with the reactive functional group. 5. A pressure-sensitive adhesive product which is provided with a pressure-sensitive adhesive layer for soft vinyl chloride formed by using the pressure-sensitive adhesive composition according to any one of claims 1 to 4, and which is applied to a soft polyvinyl chloride molded article. 6. A pressure-sensitive adhesive layer for soft vinyl chloride formed using the composition for pressure-sensitive adhesive according to claim 1, and one or both surfaces of the pressure-sensitive adhesive layer for soft vinyl chloride. An adhesive product provided with a soft polyvinyl chloride base material.