JP2000303049A - Solvent-type adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solvent-type adhesive compsn. comprising a high-solid, solvent-type adhesive which can cope with the environmental problem energy- saving and speedup of the production line, and is excellent in heat resistance, application workability and water resistance. SOLUTION: This solvent-type adhesive compsn. comprises a thermoplastic addn. polymer and an org. solvent dissolving and/or dispersing the polymer, wherein the polymer has a star-shaped block structure comprising a multi-valent mercaptan section which is a remaining part of a multi-valent mercaptan, dissociating a proton from its mercapto group, a first polymeric section extending radially from the multi-valent mercaptan section, and a second polymeric section. The polymer has a viscosity of 20,000 cP or less at 25 deg.C, the first polymeric section consists of a high glass transition point polymer having a glass transition point of 273 K or more, and the second polymeric section consists of a low glass transition point polymer having a glass transition point of lass than 273 K.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a solvent-based pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art There are various types of pressure-sensitive adhesives, such as hot-melt pressure-sensitive adhesives, solvent-type pressure-sensitive adhesives, and emulsion-type pressure-sensitive adhesives. Since the hot melt adhesive contains no or almost no organic solvent or aqueous medium, it is excellent in working environment, air pollution, danger of fire, no drying step, energy saving and the like. Solvent-based pressure-sensitive adhesives have better heat resistance and application workability than hot-melt pressure-sensitive adhesives, and have better water resistance than emulsion-type pressure-sensitive adhesives, so there is no substitute for water-resistant adhesives . However, a so-called high solid solvent-type pressure-sensitive adhesive, which reduces the amount of solvent used for environmental problems, energy saving, and speeding up the line, is required.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has been made in consideration of the above circumstances.
An object of the present invention is to provide a solvent-type pressure-sensitive adhesive composition having excellent coating workability and water resistance.

[0004]

The solvent-type pressure-sensitive adhesive composition according to the present invention contains a thermoplastic addition polymer as a polymer, and the thermoplastic addition polymer comprises a polyvalent mercaptan portion and a polyvalent mercaptan portion. A star-shaped block polymer having a first polymer portion and a second polymer portion radially extending from the polymer, wherein the first polymer portion has a high glass transition point having a glass transition point of 273K or more. The second polymer portion comprises a low glass transition point type polymer having a glass transition point of less than 273K. In the solvent-type pressure-sensitive adhesive composition according to the present invention, the polymer having the star-shaped block structure includes a preparation step, a first polymerization step, an addition step, and a second step.
And a thermoplastic addition polymer produced by the following production method including a polymerization step. The preparing step is a step of preparing a first mixture containing a polyvalent mercaptan and a first α, β-unsaturated monomer capable of producing a high glass transition point type polymer having a glass transition point of 273 K or more. is there. First
The polymerization step is a step of obtaining a reaction mixture by performing radical polymerization of the first α, β-unsaturated monomer with the mercapto group of the polyvalent mercaptan as a starting point. The adding step comprises adding a second α, β-unsaturated monomer to the reaction mixture and adding
This is a step of obtaining a second mixture capable of producing a low glass transition point type polymer having a glass transition point of less than K. The second polymerization step is a step of performing radical polymerization of a monomer contained in the second mixture.

The solvent-based pressure-sensitive adhesive composition according to the present invention comprises:
It further contains an organic solvent in which the thermoplastic addition polymer is dissolved and / or dispersed, and has a viscosity of 20,000 c at 25 ° C.
ps or less. In the solvent-type pressure-sensitive adhesive composition according to the present invention, when the high-solid type is used, the non-volatile content is 6%.
It is preferably from 0 to 80% by weight.

[0006]

According to the present invention, the pressure-sensitive adhesive composition comprises a polymer,
A first polymer portion comprising a thermoplastic polymer having a star block structure having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion; Is composed of a high glass transition point type polymer having a glass transition point of 273K or more, and the second polymer portion is composed of a low glass transition point type polymer having a glass transition point of less than 273K. In the present invention, the polymer having a star block structure can be a thermoplastic addition polymer produced by the following production method including a preparation step, a first polymerization step, an addition step, and a second polymerization step. . The preparation process is
First α, β- which can form a polyvalent mercaptan and a high glass transition point type polymer having a glass transition point of 273K or more
This is a step of preparing a first mixture containing an unsaturated monomer. The first polymerization step is a step of obtaining a reaction mixture by performing radical polymerization of the first α, β-unsaturated monomer starting from the mercapto group of the polyvalent mercaptan. By this radical polymerization, a polymer in which the first polymer portion composed of the high glass transition point type polymer radially extends from the polyvalent mercaptan portion is generated. The adding step includes adding a second α, β-unsaturated monomer to the reaction mixture to form a second glass transition point polymer having a glass transition point of less than 273K.
This is a step of obtaining a mixture. The second polymerization step is a step of performing radical polymerization of a monomer contained in the second mixture. By this radical polymerization, a thermoplastic addition polymer in which a second polymer portion composed of a low glass transition point type polymer extends radially from the polyvalent mercaptan portion of the polymer generated in the first polymerization step.

The thermoplastic addition polymer is thus:
Since a plurality of polymer portions have a branched structure (star-shaped block structure) extending radially from the polyvalent mercaptan portion, phase separation is effective. A first polymer portion comprising a high glass transition point type polymer forms a discontinuous phase;
Since it has a pseudo-crosslinked structure, it has higher cohesive strength and superior heat resistance as compared with conventional general adhesives. The higher the glass transition point of the first polymer portion, the more the pressure-sensitive adhesive composition can have excellent heat resistance. Further, the second polymer portion composed of the low glass transition point type polymer forms a continuous phase, and exhibits adhesiveness. The lower the glass transition point of the second polymer portion, the greater the effect of increasing the tackiness. The development of adhesiveness is based on the same mechanism as that of a conventional general adhesive. However, in order to achieve heat resistance, a general pressure-sensitive adhesive needs to be cross-linked, whereas the pressure-sensitive adhesive composition of the present invention does not require cross-linking. Crosslinking causes a decrease in adhesive strength or a change with time depending on the crosslinking conditions, and thus may impair the reliability of the adhesive or the adhesive product. The pressure-sensitive adhesive composition of the present invention is superior in reliability to these conventional general pressure-sensitive adhesives. Further, those using isocyanate cross-linking require curing for about one week and thus have low production efficiency, but the pressure-sensitive adhesive composition of the present invention does not need to do so. However, it is possible to crosslink and use the solvent-type pressure-sensitive adhesive composition according to the present invention.

In the present invention, the pressure-sensitive adhesive composition further contains an organic solvent in which the above-mentioned thermoplastic addition polymer is dissolved and / or dispersed, and has a viscosity at 25 ° C. of 20,000 cps or less. It has the advantages of solvent type, such as excellent properties. In the solvent-based pressure-sensitive adhesive composition according to the present invention,
Even at a nonvolatile content of 60 to 80% by weight, the viscosity at 25 ° C. is 20,000 cps or less. For this reason, even if it is made into a high solid solvent type, it is excellent in machine coatability.
When a conventional solvent-based pressure-sensitive adhesive is made into a high solid, the viscosity becomes extremely high, so it is necessary to reduce the molecular weight of the polymer, and it is necessary to include a large amount of a curing agent to have heat resistance. , Reduced tack or reduced appearance. Since the solvent-based pressure-sensitive adhesive composition according to the present invention has a high cohesive force by utilizing the phase separation structure as described above, heat resistance (e.g., 80 ° C retention). Therefore, high solidification can be achieved without deteriorating the adhesive properties.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The solvent-based pressure-sensitive adhesive composition according to the present invention has a thermoplastic polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion. Polymers have been used. The polyvalent mercaptan portion is a polyvalent mercaptan (2) described later.
Remaining portions (residues) of protons of a plurality of mercapto groups dissociated from the above mercapto group-containing mercaptan)
Say As the polyvalent mercaptan moiety, preferably,
It is a remaining portion in which protons of a plurality of mercapto groups are dissociated from a trivalent to hexavalent mercaptan described below, more preferably a tetravalent to hexavalent mercaptan described later. The reason for this is
Since the thermoplastic addition polymer has a star-shaped block structure extending radially from the same center, it is possible to expect an effect (for example, high cohesion) due to entangling between polymer portions and a change in the form of the phase separation structure. Because there is. When the polyvalent mercaptan portion is the remaining portion where the proton of the mercapto group is dissociated from divalent mercaptan, the heat resistance of the pressure-sensitive adhesive composition may not be sufficient. Further, when the polyvalent mercaptan portion is the remaining portion in which the proton of the mercapto group is dissociated from the mercaptan having a valence of 7 or more, the thermoplastic addition polymer hardly takes a structure in which the polymer portion radially extends from the same center, The desired physical properties may not be exhibited.

A polyvalent mercaptan is a compound having two or more mercapto groups per molecule. Mercaptans in which the number of mercapto groups per molecule is 2, 3,... Valuable mercaptans ... As polyvalent mercaptan, for example,
Diesters of diols such as ethylene glycol and 1,4-butanediol and carboxyl-containing mercaptans; compounds having three or more hydroxyl groups such as trimethylolpropane, pentaerythritol, dipentaerythritol and polyester compounds of carboxyl-containing mercaptans; Compounds having three or more mercapto groups such as trithioglycerin; 2-di-n-butylamino-
4,6-dimercapto-S-triazine, 2,4,6-
Triazine polyvalent thiols such as trimercapto-S-triazine; compounds obtained by adding hydrogen sulfide to a plurality of epoxy groups of a polyepoxy compound to introduce a plurality of mercapto groups; a plurality of carboxyl groups of a polyvalent carboxylic acid And an ester compound obtained by esterification of mercaptoethanol with any one of them. Any one of them can be used alone or in combination of two or more.
Here, the carboxyl group-containing mercaptans are compounds having one mercapto group and one carboxyl group, such as thioglycolic acid, mercaptopropionic acid, and thiosalicylic acid. It should be noted that a mercaptan having only one mercapto group cannot be used as a mercaptan portion of a thermoplastic addition polymer because it does not give a structure in which the polymer portion extends radially.

From the viewpoint of forming a polymer having a star-shaped block structure, the polyvalent mercaptan is preferably a compound having 3 to 6 mercapto groups (that is, a 3 to 6 functional mercaptan), more preferably 4 to 6 functional mercaptan. Compounds having six mercapto groups (i.e., 4-6 functional mercaptans). Mercaptans having only one mercapto group do not provide a radially extended structure of the polymer portion. A mercaptan having more than six mercapto groups does not have a structure extending radially from the same center, and thus may not exhibit desired physical properties. Examples of the polyvalent mercaptan include trifunctional mercaptans such as trithioglycerin, trimethylolpropane trithioglycolate, and trimethylolpropane trithiopropionate; pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate; A hexafunctional mercaptan such as dipentaerythritol hexakisthioglycolate and dipentaerythritol hexakisthiopropionate; a compound obtained by adding hydrogen sulfide to a trivalent to hexavalent epoxy compound; Examples thereof include mercaptoethanol adducts of hexavalent carboxylic acids, and at least one of them is used.

[0012] The first polymer portion and the second polymer portion extend radially from the polyvalent mercaptan portion. The polymer portion extends radially from the polyvalent mercaptan portion,
When two polymer portions per polymer extend in two directions from the polyvalent mercaptan portion (including the case where they extend linearly), three or more polymer portions per polymer are multivalent. This refers to the case where it extends in three or more directions from the mercaptan portion. A carbon atom at one end of the polymer moiety is bonded to a sulfur atom derived from the mercapto group of the polyvalent mercaptan moiety. The first polymer portion and the second polymer portion each usually have a number average molecular weight of 1,000 to 150,000.
0, preferably 3,000 to 100,000. If the number average molecular weight of the polymer portion falls below the above range, it may not be possible to introduce the properties based on the polymer portion into the thermoplastic addition polymer, and only when the viscosity of the high solid solvent type pressure-sensitive adhesive becomes higher, the viscosity increases. And the viscosity at the time of production becomes high, which may be undesirable in terms of productivity.

The thermoplastic addition polymer has one or more first polymer portions and one or more second polymer portions per polymer. The polymer portion is a portion having a homopolymer or copolymer structure obtained by radical polymerization of a polymerizable unsaturated monomer. The polymer portion obtained by radical polymerization is more diverse in the type of composition than the polymer portion generated by ionic polymerization such as anionic polymerization, except that the type of monomer used is also capable of radical polymerization. It is not particularly limited, and it may be a copolymer. The first polymer portion is at least 273K, preferably at least 333K,
More preferably, it is composed of a high glass transition point type polymer having a glass transition point of 353 K or more. The first polymer portion composed of a high glass transition point type polymer is phase-separated from the second polymer portion to form a discontinuous phase and has a pseudo-crosslinked structure, so that the adhesive composition has excellent heat resistance. It shall be assumed. The higher the glass transition point of the first polymer portion, the greater the effect of improving the heat resistance.

[0014] The second polymer portion comprises a low glass transition type polymer having a glass transition point of less than 273K, preferably less than 263K, more preferably less than 250K. The second polymer portion composed of the low glass transition point type polymer is the first polymer portion.
It separates from the polymer portion to form a continuous phase, and exhibits adhesiveness. The lower the glass transition point of the second polymer portion, the greater the effect of increasing the adhesive strength. The difference in the glass transition point between the first polymer portion and the second polymer portion is that when the polymer portion is composed of a homopolymer, the difference in the monomer units constituting the polymer and the polymer portion are the same. When it is composed of a polymer, it is obtained by a difference in monomer units and / or a difference in the ratio of monomer units.

The first polymer portion comprises first α, β described later.
-It is composed of a high glass transition point type polymer produced by radical polymerization of an unsaturated monomer. Further, the second polymer portion is formed of a low glass transition point type polymer generated by radical polymerization of a second α, β-unsaturated monomer described later. The first α,
As a β-unsaturated monomer, 27
3K or more, preferably 333K or more, more preferably 3
Any monomer can be used as long as it produces a high glass transition point type polymer (homopolymer or copolymer) having a glass transition point of 53K or more. For example,
(Meth) acrylic acid; alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, phenyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentadienyl (meth) acrylate , Adamantyl (meth) acrylate, hydroxyethyl (meth) acrylate,
(Meth) acrylates represented by hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, and the like; α-methylstyrene; Styrene-based polymerizable monomers such as vinyl toluene and styrene; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and vinyl acetate; fumaric acid, monoalkyl esters of fumaric acid, and dialkyl fumaric acid Esters: maleic acid, monoalkyl esters of maleic acid, dialkyl esters of maleic acid; itaconic acid, monoalkyl esters of itaconic acid, dialkyl esters of itaconic acid; also succinic anhydride Or a half ester of phthalic anhydride and hydroxyethyl (meth) acrylate; (meth) acrylonitrile, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl ketone, vinyl pyridine, vinyl carbazole, etc. Or two or more can be used together.

As the second α, β-unsaturated monomer, the first α, β-unsaturated monomer remaining without reacting with the second α, β-unsaturated monomer in the first polymerization step is used. A mixture with a saturated monomer or the second α, β-unsaturated monomer itself may have a glass transition point of less than 273K, preferably less than 263K, more preferably less than 250K by radical polymerization. Any monomer can be used as long as it produces a glass transition point polymer (homopolymer or copolymer). For example, alkyl acrylates having an alkyl group having 2 to 18 carbon atoms, such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and dodecyl acrylate; hydroxyethyl acrylate, hydroxypropyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, ethoxyethoxyethyl acrylate And so on.
Any of them can be used alone or in combination of two or more. Further, the first α, β-unsaturated monomer may be contained within a range satisfying a glass transition temperature of less than 273K.

By selecting a combination of the first polymer portion and the second polymer portion, it is possible to achieve conflicting performances such as heat resistance and tackiness, and adhesion and toughness. For example, when a thermoplastic addition polymer is used as a pressure-sensitive adhesive (pressure-sensitive adhesive), the second polymer portion composed of a low glass transition point type polymer has a first polymer portion composed of a high glass transition point type polymer. The thermoplastic addition polymer is designed to occupy more, more than more, coalescing parts. The number average molecular weight of the thermoplastic addition polymer is from 10,000 to 200,000. When the number average molecular weight is less than the above range, heat resistance is insufficient and cohesive strength (holding force) during use is reduced. When the number average molecular weight exceeds the above range, the viscosity of the pressure-sensitive adhesive solution is high, and the handleability is deteriorated. In consideration of the balance that the heat resistance is sufficiently high and the viscosity of the pressure-sensitive adhesive solution is sufficiently low, the number average molecular weight of the thermoplastic addition polymer is preferably 10,000.
0 to 100,000.

The thermoplastic addition polymer has a molecular weight distribution (Mw
/ Mn) is preferably 6 or less. Preferred examples of the pressure-sensitive adhesive composition of the present invention are described below. (1) A thermoplastic addition polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion, wherein the first polymer portion has a temperature of 273K or more. A high glass transition point type polymer having a glass transition point, wherein the second polymer portion is 25
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than 0K. (2) a thermoplastic addition polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion, wherein the first polymer portion has a temperature of 333K or more. A high glass transition point type polymer having a glass transition point, wherein the second polymer portion is 27
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point type polymer having a glass transition point of less than 3K. (3) a thermoplastic addition polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion, wherein the first polymer portion has a temperature of 333K or more. A high glass transition point type polymer having a glass transition point, wherein the second polymer portion is 25
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than 0K. (4) a thermoplastic addition polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion, wherein the first polymer portion has a 353K or more. A high glass transition point type polymer having a glass transition point, wherein the second polymer portion is 27
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point type polymer having a glass transition point of less than 3K. (5) a thermoplastic addition polymer having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion, wherein the first polymer portion has a temperature of 353K or more. A high glass transition point type polymer having a glass transition point, wherein the second polymer portion is 25
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than 0K. (6) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer portion is 1,000 to 150,000
0, the number average molecular weight of the second polymer portion is 1,000 to 15
Solvent-type pressure-sensitive adhesive composition having a molecular weight of 000. (7) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer portion is from 3,000 to 100,00
0, the number average molecular weight of the second polymer portion is 3,000-10
Solvent-type pressure-sensitive adhesive composition having a molecular weight of 000. (8) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer portion is 1,000 to 150,000
0, the number average molecular weight of the second polymer portion is 1,000 to 15
000, the number average molecular weight of the thermoplastic addition polymer is 1
A solvent-based pressure-sensitive adhesive composition having a molecular weight of from 000 to 200,000. (9) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer portion is from 3,000 to 100,00
0, the number average molecular weight of the second polymer portion is 3,000-10
000, the number average molecular weight of the thermoplastic addition polymer is 1
Solvent-type pressure-sensitive adhesive composition having a molecular weight of from 000 to 100,000. (10) The solvent-based pressure-sensitive adhesive composition according to any one of (1) to (9), wherein the molecular weight distribution (Mw / Mn) of the thermoplastic addition polymer is 6 or less. (11) A solvent-type pressure-sensitive adhesive composition, wherein the polyvalent mercaptan moiety is a residue of a 3 to 6 functional mercaptan. (12) The solvent-based pressure-sensitive adhesive composition according to any one of the above (1) to (10), wherein the polyvalent mercaptan moiety is a residue of a 3 to 6-functional mercaptan. (13) In any one of the above (11) to (12),
A solvent-type pressure-sensitive adhesive composition, wherein the polyvalent mercaptan moiety is a residue of a 4- to 6-functional mercaptan.

The thermoplastic addition polymer used in the present invention is produced, for example, by a method for producing a thermoplastic addition polymer described below. This manufacturing method includes a preparation step, a first polymerization step, an addition step, and a second polymerization step described below. The preparing step is a step of preparing a first mixture containing a polyvalent mercaptan and a first α, β-unsaturated monomer capable of producing a high glass transition point type polymer having a glass transition point of 273 K or more. is there. Since the first α, β-unsaturated monomer and the polyvalent mercaptan have already been described, the description is omitted here.

When polymerization is carried out in the presence of a polyvalent mercaptan, the polymerization proceeds from the mercapto group of the polyvalent mercaptan as a starting point. A thermoplastic addition polymer having a modified star block structure is formed. The first mixture contains a polyvalent mercaptan, for example, from 0.01 to 1 based on 100 parts by weight of the first α, β-unsaturated monomer.
Contains 0 parts by weight. When the amount of the polyvalent mercaptan is out of the above range, the number average molecular weight of the first polymer portion is 1,000 to 15
It may be out of the range of 10,000 or the number average molecular weight of the thermoplastic addition polymer may be out of the range of 10,000 to 200,000. In consideration of this point, the amount of the polyvalent mercaptan is more preferably 0.05 to 5 parts by weight.

[0021] The first mixture may further include a medium in which the first α, β-unsaturated monomer and the polyvalent mercaptan are dissolved and / or dispersed. The medium may be any medium in which the monomer and the obtained polymer are soluble.
The amount of the medium is the amount of the first α, β-unsaturated monomer and the second α, β-unsaturated monomer.
For example, 0 to 2 with respect to the total amount with the β-unsaturated monomer.
00% by weight, preferably 0 to 100% by weight. If the ratio exceeds the above range, the polymerization rate is lowered and the cost in terms of solid content is increased, which is not industrially preferable. Examples of the medium include 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; Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone are exemplified. The organic solvent may be a single solvent or a mixed solvent.

The first polymerization step is a step of obtaining a reaction mixture by performing radical polymerization of the first α, β-unsaturated monomer starting from the mercapto group of the polyvalent mercaptan. The radical polymerization can be carried out by a general radical polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like. In order to obtain an inexpensive polymer, a bulk polymerization method containing no extra volatile components is preferred. The polymerization temperature is 3
The temperature is preferably from 0 to 200 ° C, more preferably from 100 to 150 ° C, which enables stable bulk polymerization without using a polymerization initiator. In the first polymerization step, a usual radical polymerization initiator (for example, 2,2'-azobisisobutyronitrile,
Azo-based polymerization initiators such as 2,2'-azobiscyclohexanecarbonitrile; peroxide-based polymerization initiators such as benzoyl peroxide) can be used.
It is not more than 1/3, preferably not more than 1/10, more preferably not used, of the polyvalent mercaptan. When the polymerization initiator is used in a larger amount than the above ratio, in addition to the polymer portion extended from the polyvalent mercaptan, a large amount of the polymer extended from the polymerization initiator is generated, and a thermoplastic addition polymer having a star block structure Generation efficiency is reduced.

By the radical polymerization in the first polymerization step, a high glass transition point type polymer having a glass transition point of 273K or more at one or more sulfur residues of a mercapto group in each molecule of polyvalent mercaptan is obtained. A product having the carbon atom at one end of the carbon chain bonded is obtained. The product contains a first polymer portion radially extending from the polyvalent mercaptan portion and has unreacted mercapto groups. The first polymer portion comprises a high glass transition point polymer. In order to efficiently bind one end of the first polymer portion to the sulfur residue, it is preferable not to add an unnecessary polymerization initiator to the polymerization system. The radical polymerization in the first polymerization step is performed, for example, at a conversion of 30 to 95%, preferably at a conversion of 50 to 90%.
%, More preferably until the conversion reaches 70 to 85%. If the polymerization rate is lower than the above range, sufficient heat resistance may not be obtained, or a large amount of the first α, β-unsaturated monomer remains, so that the second polymer portion obtained in the second polymerization step May be insufficient in tackiness. If the degree of polymerization is higher than the above range, the remaining mercapto groups decrease, the production efficiency of the block polymer becomes poor, and sufficient heat resistance may not be obtained. In order to facilitate the formation of different polymer portions in the first polymerization step and a later-described second polymerization step, the remaining first polymerizing step is performed after the first polymerization step.
It is also possible to volatilize and remove the α, β-unsaturated monomer.

The addition step comprises adding a second α, β-unsaturated monomer to the reaction mixture obtained in the first polymerization step,
This is a step of obtaining a second mixture capable of producing a low glass transition point type polymer having a glass transition point of less than. The second α, β
-Unsaturated monomers have already been described, and thus description thereof is omitted here. When the thermoplastic addition polymer is used as a pressure-sensitive adhesive (pressure-sensitive adhesive), the second polymer portion composed of a low glass transition type polymer is replaced with the first polymer portion composed of a high glass transition point polymer. The thermoplastic addition polymer is designed to occupy more, or more, parts.

A first α, β-unsaturated monomer and a second α, β-unsaturated monomer
The combination with the β-unsaturated monomer is set from the viewpoint of increasing the cohesive force of the thermoplastic addition polymer by introducing a block structure having a polymer portion having a different Tg. First, a first α, β-unsaturated monomer capable of producing a high glass transition point polymer having a glass transition point of 273K or more, and a low glass transition point polymer having a glass transition point of less than 273K In combination with a second α, β-unsaturated monomer capable of producing From the viewpoint of further improving the cohesive force of the thermoplastic addition polymer, preferably,
A first α, β-unsaturated monomer capable of forming a high glass transition point type polymer having a glass transition point of 333 K or more;
Combination with a second α, β-unsaturated monomer capable of producing a low glass transition type polymer having a glass transition point of less than 50K, more preferably a high glass transition having a glass transition point of 353K or more A first [alpha], [beta] -unsaturated monomer capable of forming a point polymer and a second [alpha], [beta] -unsaturated monomer capable of forming a low glass transition point polymer having a glass transition point of less than 250K It is a combination with a monomer.

The amount of the second α, β-unsaturated monomer is
The amount is, for example, in the range of 50 to 2,000 parts by weight based on 100 parts by weight of the polymer formed from the α, β-unsaturated monomer. Outside of this range, the thermoplastic addition polymer may not have the performance derived from the star block structure. Considering this point, the amount of the second α, β-unsaturated monomer is 1
00 to 1000 parts by weight is preferred. In the addition step, the second
A method of adding the α, β-unsaturated monomer in a lump or a method of adding it dropwise. The second mixture may further include a medium in which the polymer produced in the first polymerization step and the second α, β-unsaturated monomer are dissolved and / or dispersed. The medium may be any medium in which the monomer and the obtained polymer are soluble. The amount of the medium is, for example, 0 to 200% by weight, preferably 0 to 100% by weight, based on the total amount of the first α, β-unsaturated monomer and the second α, β-unsaturated monomer. % By weight. If the ratio exceeds the above range, the polymerization rate is lowered and the cost in terms of solid content is increased, which is not industrially preferable. Examples of the medium include 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; Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone are exemplified. The organic solvent may be a single solvent or a mixed solvent.

The second polymerization step is a step of performing radical polymerization of the monomers contained in the second mixture. This radical polymerization is carried out starting from all or a part of the remaining mercapto groups in the polyvalent mercaptan to produce a low glass transition point type polymer. A product is obtained in which one end of the second polymer portion is bonded to the sulfur residue of the mercapto group serving as the starting point. The second polymer portion comprises a low glass transition point polymer. This product may have unreacted mercapto groups. In this case, by repeating the second polymerization step twice, a polymer portion having a third different composition is introduced, and by repeating the second polymerization step three times, the third and fourth different compositions are obtained. Each time the number of repetitions of the second polymerization step is increased, a polymer portion having a further different composition can be introduced.

The radical polymerization can be carried out by a conventional radical polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like. In order to obtain an inexpensive polymer, a bulk polymerization method containing no extra volatile components is preferred. The polymerization temperature is preferably from 30 to 200 ° C., more preferably from 100 to 1 to allow stable bulk polymerization without using a polymerization initiator.
50 ° C. In the second polymerization step, an ordinary radical polymerization initiator (for example, an azo-based polymerization initiator such as 2,2'-azobisisobutyronitrile and 2,2'-azobiscyclohexanecarbonitrile; benzoyl peroxide and the like) Peroxide-based polymerization initiator) can be used, but in terms of weight ratio,
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, in addition to the polymer portion extended from the polyvalent mercaptan, a large amount of the polymer extended from the polymerization initiator is generated, and a thermoplastic addition polymer having a star block structure Generation efficiency is reduced.

After the completion of the addition in the second polymerization step, it is possible to carry out radical polymerization for aging, if necessary. When the reaction mixture obtained in the second polymerization step does not contain a volatile component such as a solvent or a residual monomer, a thermoplastic addition polymer can be obtained as it is. When the reaction mixture contains a volatile component, a thermoplastic addition polymer is obtained by removing the volatile component using a device such as a twin screw extruder or a thin film evaporator. In the above-mentioned production method, the polymerization rate in the first polymerization step is set to 50% or more, and the second α, β-unsaturated monomer is added at a time after the remaining polymerizable unsaturated monomer is volatilized and removed if necessary. In the case, the first glass transition point type polymer is used.
A thermoplastic addition polymer having a polymer portion and a second polymer portion composed of a low glass transition point type polymer is obtained.

Preferred examples of the solvent-based pressure-sensitive adhesive composition according to the present invention, in which a thermoplastic addition polymer is obtained by the above-mentioned production method, are as follows. (1) As the first α, β-unsaturated monomer, 273K
The second α, β-unsaturated monomer having a low glass transition point having a glass transition point of less than 250 K is used as the second α, β-unsaturated monomer. Solvent-type pressure-sensitive adhesive composition using a substance capable of forming coalescence. (2) 333K as the first α, β-unsaturated monomer
A polymer capable of producing a high glass transition point polymer having the above glass transition point is used. Solvent-type pressure-sensitive adhesive composition using a substance capable of forming coalescence. (3) 333K as the first α, β-unsaturated monomer
The second α, β-unsaturated monomer having a low glass transition point having a glass transition point of less than 250 K is used as the second α, β-unsaturated monomer. Solvent-type pressure-sensitive adhesive composition using a substance capable of forming coalescence. (4) 353 K as the first α, β-unsaturated monomer
A polymer capable of producing a high glass transition point polymer having the above glass transition point is used. Solvent-type pressure-sensitive adhesive composition using a substance capable of forming coalescence. (5) 353K as the first α, β-unsaturated monomer
The second α, β-unsaturated monomer having a low glass transition point having a glass transition point of less than 250 K is used as the second α, β-unsaturated monomer. Solvent-type pressure-sensitive adhesive composition using a substance capable of forming coalescence. (6) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer produced in the polymerization step is 1,000
A solvent-based pressure-sensitive adhesive composition having a molecular weight of up to 150,000. (7) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer produced in the polymerization step is 3,000
A solvent-based pressure-sensitive adhesive composition having a viscosity of 100 to 100,000. (8) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer produced in the polymerization step is 1,000
A solvent-type pressure-sensitive adhesive composition, wherein the number average molecular weight of the thermoplastic addition polymer is 10,000 to 200,000. (9) In any one of the above (1) to (5), the first
The number average molecular weight of the polymer produced in the polymerization step is 3,000
A solvent-type pressure-sensitive adhesive composition, wherein the number average molecular weight of the thermoplastic addition polymer is from 50,000 to 150,000. (10) The solvent-based pressure-sensitive adhesive composition according to any one of (1) to (9), wherein the molecular weight distribution (Mw / Mn) of the thermoplastic addition polymer is 6 or less. (11) An adhesive composition, wherein the polyvalent mercaptan is a 3-6 functional mercaptan. (12) The solvent-based pressure-sensitive adhesive composition according to any one of (1) to (10) above, wherein the polyvalent mercaptan is a 3 to 6-functional mercaptan. (13) The solvent-based pressure-sensitive adhesive composition according to any one of the above (11) to (12), wherein the polyvalent mercaptan is a 4- to 6-functional mercaptan.

The organic solvent used in the present invention may be any one in which the thermoplastic addition polymer can be dissolved and / or dispersed. Examples thereof include aromatic hydrocarbons such as toluene and xylene; ethyl acetate and butyl acetate. Esters such as cyclohexane; alicyclic hydrocarbons such as cyclohexane; aliphatic hydrocarbons such as hexane and pentane; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohols such as methanol, ethanol, propanol and butanol. Organic solvents. The organic solvent may be a single solvent or a mixed solvent. In the solvent-type pressure-sensitive adhesive composition according to the present invention, the non-volatile content is preferably 60 to 80% by weight. In this case, the solvent-based pressure-sensitive adhesive composition is a high solid solvent-type pressure-sensitive adhesive. The non-volatile content is a thermoplastic addition polymer. Non-volatile content concentration is 80
If the content is more than 60% by weight, it is not possible to satisfy the adhesive properties while maintaining the viscosity of 20,000 cps or less. VOC: reduction of volatile organic compounds), energy saving effect, and line speed-up effect are reduced. The point of satisfying the adhesive properties while maintaining the viscosity of the adhesive composition at 20,000 cps or less, and reducing the reduction of the environmental problem improving effect, energy saving effect, and line speed increasing effect which are the merits of high solidification. From, the nonvolatile content concentration
More preferably, it is 65 to 75% by weight.

The solvent-based pressure-sensitive adhesive composition according to the present invention comprises:
Since the thermoplastic addition polymer has a low molecular weight, the viscosity at 25 ° C. of 20,000 c
ps or less. When the viscosity is larger than 20,000 cps, the coating workability or the coating property is poor. The viscosity is preferably 10,000 cps or less from the viewpoint that there is an advantage that the coatability is good and the line speed is increased. The viscosity is a value measured at 25 ° C. under the conditions of a B-type viscometer (BM type), # 4, 30 rpm. The thermoplastic addition polymer is, for example, 1
000-30,000, preferably 13,000-
When it has a number average molecular weight of 20,000, it has the further advantage of being excellent in the balance between heat resistance and adhesive properties, while being high solid and low in viscosity.

As a method of dissolving and / or dispersing the thermoplastic addition polymer in an organic solvent, for example, it is a common method to coexist during the polymerization step. In some cases, the thermoplastic addition polymer and the organic solvent are mixed together. May be mixed and dissolved by heating. Preferred examples of the pressure-sensitive adhesive composition of the present invention are described below from the viewpoints of the concentration of non-volatile components and the viscosity. (1) a nonvolatile content of 65 to 75% by weight,
A solvent-based pressure-sensitive adhesive composition having a viscosity at ℃ of 20,000 cps or less. (2) a nonvolatile component concentration of 60 to 80% by weight;
A solvent-based pressure-sensitive adhesive composition having a viscosity at 10,000 ° C. of 10,000 cps or less. (3) a nonvolatile content of 65 to 75% by weight;
A solvent-based pressure-sensitive adhesive composition having a viscosity at 10,000 ° C. of 10,000 cps or less. (4) In any one of the above (1) to (3), the first
The polymer portion is composed of a high glass transition point type polymer having a glass transition point of 333 K or more, and the second polymer portion is 250
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than K. (5) In any one of the above (1) to (3), the first
The polymer portion is composed of a high glass transition type polymer having a glass transition point of 353 K or more, and the second polymer portion is 250
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than K. (6) In any one of the above (1) to (3), the first
The polymer portion is composed of a high glass transition point type polymer having a glass transition point of 353 K or more, and the second polymer portion is 230
A solvent-type pressure-sensitive adhesive composition comprising a low glass transition point polymer having a glass transition point of less than K. (7) In any one of the above (4) to (6), the first
The number average molecular weight of the polymer part is 1,000 to 10,000.
0, the number average molecular weight of the second polymer portion is 1,000-2.
Solvent-type pressure-sensitive adhesive composition having a molecular weight of 000. (8) In any one of the above (4) to (6), the first
The number average molecular weight of the polymer portion is 1,500 to 5,000,
The number average molecular weight of the second polymer portion is from 3,000 to 15.0
00, a solvent-type pressure-sensitive adhesive composition. (9) In any one of the above (4) to (6), the first
The number average molecular weight of the polymer part is 1,000 to 10,000.
0, the number average molecular weight of the second polymer portion is 1,000-2.
000, the number average molecular weight of the thermoplastic addition polymer is 1
A solvent-based pressure-sensitive adhesive composition having a molecular weight of from 000 to 30,000. (10) In any one of the above (4) to (6), the first
The number average molecular weight of the polymer portion is 1,500 to 5,000,
The number average molecular weight of the second polymer portion is from 3,000 to 15.0
00, the number average molecular weight of the thermoplastic addition polymer is 13,00
A solvent-type pressure-sensitive adhesive composition having a molecular weight of 0 to 20,000. (11) The solvent-based pressure-sensitive adhesive composition according to any one of the above (4) to (10), wherein the molecular weight distribution (Mw / Mn) of the thermoplastic addition polymer is 6 or less. (12) The solvent-type pressure-sensitive adhesive composition according to any one of the above (4) to (11), wherein the polyvalent mercaptan moiety is a residue of a 3 to 6-functional mercaptan. (13) The solvent-based pressure-sensitive adhesive composition according to any one of (4) to (11), wherein the polyvalent mercaptan moiety is a residue of a 4 to 6-functional mercaptan. (14) In any one of the above (1) to (3), the first
As the α, β-unsaturated monomer, one capable of producing a high glass transition point type polymer having a glass transition point of 333 K or more is used, and as the second α, β-unsaturated monomer, 250
A solvent-type pressure-sensitive adhesive composition using a substance capable of producing a low glass transition point type polymer having a glass transition point of less than K. (15) In any one of the above (1) to (3), the first
As the α, β-unsaturated monomer, one capable of producing a high glass transition point type polymer having a glass transition point of 353 K or more is used, and as the second α, β-unsaturated monomer, 250
A solvent-type pressure-sensitive adhesive composition using a substance capable of producing a low glass transition point type polymer having a glass transition point of less than K. (16) In any one of the above (1) to (3), the first
As the α, β-unsaturated monomer, one capable of producing a high glass transition point type polymer having a glass transition point of 353 K or more is used, and as the second α, β-unsaturated monomer, 230 is used.
A solvent-type pressure-sensitive adhesive composition using a substance capable of producing a low glass transition point type polymer having a glass transition point of less than K. (17) In any one of the above (14) to (16),
The number average molecular weight of the polymer formed in the first polymerization step is 1,0
The pressure-sensitive adhesive composition, which is from 00 to 10,000. (18) In any one of the above (14) to (16),
The number average molecular weight of the polymer formed in the first polymerization step is 3,0
Solvent-type pressure-sensitive adhesive composition having a pH of from 00 to 6,000. (19) In any one of the above (14) to (16),
The number average molecular weight of the polymer formed in the first polymerization step is 1,0
A solvent-based pressure-sensitive adhesive composition, wherein the number-average molecular weight of the thermoplastic addition polymer is from 10,000 to 30,000. (20) In any one of the above (14) to (16),
The number average molecular weight of the polymer formed in the first polymerization step is 3,0
A solvent-type pressure-sensitive adhesive composition, wherein the number average molecular weight of the thermoplastic addition polymer is from 13,000 to 20,000. (21) In any one of the above (14) to (20),
A solvent-type pressure-sensitive adhesive composition having a molecular weight distribution (Mw / Mn) of 6 or less of a thermoplastic addition polymer. (22) In any one of the above (14) to (21),
The polyvalent mercaptan is a 3-6 functional mercaptan,
Solvent-type pressure-sensitive adhesive composition. (23) In any one of the above (14) to (21),
The polyvalent mercaptan is a 4-6 functional mercaptan,
Solvent-type pressure-sensitive adhesive composition.

[Other Embodiments of the Pressure-Sensitive Adhesive Composition] Other embodiments of the pressure-sensitive adhesive composition of the present invention will be described below. According to another aspect α, the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition for making a pressure-sensitive adhesive for soft PVC applied to a flexible polyvinyl chloride molded article, and includes an acrylic block polymer. And an organic solvent in which an acrylic block polymer is dissolved and / or dispersed.
The acrylic block polymer is produced by a production method including a preparation step, a first polymerization step, an addition step, and a second polymerization step. The preparing step is a step of preparing a first mixture containing a polyvalent mercaptan and a first α, β-unsaturated monomer capable of producing a high glass transition point type polymer having a glass transition point of 273 K or more. is there. The first polymerization step is a step of obtaining a reaction mixture by performing radical polymerization of the first α, β-unsaturated monomer starting from the mercapto group of the polyvalent mercaptan. In the addition step, a monomer mixture containing a (meth) alkyl acrylate monomer which can form a polymer that is incompatible with the high glass transition point type polymer is added to the reaction mixture, and the second mixture is added. This is the step of obtaining. The second polymerization step is a step of performing radical polymerization of a monomer contained in the second mixture.

The pressure-sensitive adhesive composition of the present invention has another embodiment β
According to this, the composition is the same as the pressure-sensitive adhesive composition of the embodiment α except that the monomer mixture further contains a reactive functional group-containing α, β-unsaturated monomer. The pressure-sensitive adhesive composition of the present invention, according to another embodiment γ, except that the pressure-sensitive adhesive composition further includes a crosslinking agent having at least two functional groups capable of reacting with the reactive functional group.
Same as the pressure-sensitive adhesive composition of the embodiment α or β. The pressure-sensitive adhesive product using the pressure-sensitive adhesive composition of the present invention, according to another aspect δ, includes a pressure-sensitive adhesive layer for soft PVC formed using the pressure-sensitive adhesive composition of any of aspects α to γ. And
Applied to flexible polyvinyl chloride molded products.

According to another aspect ε, the pressure-sensitive adhesive product using the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive for flexible PVC formed using any of the pressure-sensitive adhesive compositions of modes α to γ. And a soft polyvinyl chloride substrate adhered to one or both sides of the soft PVC adhesive layer. Aspect α
The actions of the pressure-sensitive adhesive composition from (g) to (g) and the pressure-sensitive adhesive products from modes (δ) to (e) are as follows. In the acrylic block polymer of the pressure-sensitive adhesive composition according to Aspects α to γ, the portion of the high glass transition point type polymer is a polymer of a monomer mixture containing a (meth) acrylic acid alkyl ester monomer. The high glass transition point polymer portion and the polymer portion of the monomer mixture are chemically bonded to each other. 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.

Since the pressure-sensitive adhesive compositions of the embodiments α to γ contain an acrylic block polymer and an organic solvent, they have an excellent balance between cohesive force and adhesive force, and cause a decrease in cohesive force due to migration of a plasticizer. It can be used to make a pressure-sensitive adhesive layer for flexible PVC which is difficult and has an excellent shelf life which is important for practical use of the pressure-sensitive adhesive product for flexible PVC. In the pressure-sensitive adhesive composition of Embodiment β, since the monomer mixture further includes a reactive functional group-containing α, β-unsaturated monomer, a crosslinking agent having a functional group that reacts with these reactive functional groups is used. It has the further advantage that it can be used to control the cohesion arbitrarily. The pressure-sensitive adhesive composition of Embodiment γ has at least two functional groups that can react with the reactive functional group when the monomer mixture further contains a reactive functional group-containing α, β-unsaturated monomer. Since a crosslinking agent is further included, there is an additional advantage that a sufficient cohesive force can be obtained with a small amount of the crosslinking agent.

The pressure-sensitive adhesive product of the embodiment δ or ε is provided with the pressure-sensitive adhesive layer for flexible PVC formed using the pressure-sensitive adhesive composition of the embodiments α to γ, so that it can be applied to a flexible polyvinyl chloride molded article. Then, the cohesive force and the adhesive force are well balanced, the cohesive force is hardly reduced due to the transfer of the plasticizer, and the shelf life of the soft PVC adhesive product, which is practically important, is excellent. Hereinafter, the pressure-sensitive adhesive composition in aspects α to γ will be described in detail. The pressure-sensitive adhesive composition of the embodiment α is a pressure-sensitive adhesive composition for producing a pressure-sensitive adhesive for flexible PVC applied to a flexible polyvinyl chloride molded article, and contains an acrylic polymer and an organic solvent. The organic solvent contains the acrylic block polymer in a dissolved and / or dispersed state.

The acrylic block polymer 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 multivalent mercaptan and 2
This is a step of preparing a first mixture containing a first α, β-unsaturated monomer capable of producing a high glass transition point type polymer having a glass transition point of 73 K or more. In the first polymerization step, the first polymerization starts with the mercapto group of the polyvalent mercaptan as a starting point.
Is a step of obtaining a reaction mixture by performing radical polymerization of α, β-unsaturated monomers. The addition step is a reaction in which a monomer mixture containing a (meth) acrylic acid alkyl ester monomer, which can form 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 performing radical polymerization of a monomer contained in the second mixture.

Since the polyvalent mercaptan has already been described, the description is omitted here. Polyvalent mercaptan used in the pressure-sensitive adhesive composition of the embodiments α to γ is, from the viewpoint of efficiently producing a block polymer, and by introducing a structure in which the obtained polymer radially extends from the same center. From the viewpoint of higher performance, preferably 2-1
Compounds having 0 mercapto groups (that is, 2 to 1
(0-valent mercaptan), and more preferably a compound having 3 to 6 mercapto groups (i.e., 3 to 6-valent mercaptan). Mercaptans having only one mercapto group do not provide a radially extending structure of the polymer portion.
Mercaptans having more than 10 mercapto groups are
Since the structure does not extend radially from the same center, desired physical properties may not be exhibited.

In the acrylic block polymer, the plurality of radially extending polymer portions have two or more different compositions. This difference in composition is, 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 the copolymer, It can be obtained by differences in units, number average molecular weight of the polymer, differences in the ratio of monomer units, and the like. The polymer portion usually has a number average molecular weight of 1,000 to 500,000, preferably 5,000 to 200,000, more preferably 10,000 to 100,000. If the number average molecular weight of the polymer portion is below 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 viscosity at the time of production increases, which is preferable in terms of productivity. May not be.

In the acrylic block polymer, the combination of polymer portions having different compositions differs depending on the performance (or use) required for the block polymer. Basically, the combination of polymer portions is a combination of polymer portions derived from polymers having different glass transition points (Tg). By combining the polymer portions derived from the polymers having different Tg, the polymer portions derived from the polymer having a low Tg form a continuous phase. As an example of such a block polymer, a combination of polymethyl methacrylate (PMMA) as a polymer having a high Tg and a combination of polybutyl acrylate (PBA) as a polymer having a low Tg can be given. For this combination, PM
The number average molecular weight of MA is preferably 5,000 to 200,000, and the number average molecular weight of PBA is 10,000 to 15
000 is preferable, and the weight ratio of PMMA / PBA is 1
The range of 0/90 to 90/10 is preferred. Outside 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 or
Alternatively, it is necessary to lower the melt viscosity of the polymer having a low Tg.

In the acrylic block polymer, the polyvalent methacrylate portion is a residue of a trivalent to hexavalent mercaptan, and the plurality of polymer portions have two different compositions and have the following general formula (1):

[0044]

Embedded image

A polymer represented by the following formula is possible. In the above formula (1), polymer portions 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 (1), the following formula:

[0046]

Embedded image

The moiety represented by is a residue of a trivalent to hexavalent mercaptan. In the above formula (1), n + m is a number equal to or greater than 3 and equal to or less than the valency of the residue of the mercaptan, and n is 0.1 or less.
1 or more, preferably 0.5 or more, m is 0.1 or more,
Preferably, the number is 0.5 or more. If n or m is less than the above-mentioned value, there is a possibility that desired sufficient performance may not be obtained. The first α, β-unsaturated monomer has a glass transition point of 273 K or more, preferably 300 K or more, and has at least one high glass transition point weight selected from the group consisting of homopolymers and copolymers. At least one monomer capable of forming a coalescence. 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 the cohesive force is greatly reduced due to the transfer of the plasticizer. As the first α, β-unsaturated monomer, for example, at least one selected from the group consisting of styrene, vinyl acetate, acrylonitrile, methacrylonitrile and methyl methacrylate is 5 to 40% by weight, preferably 10 to 40% by weight. 30
A group consisting of the above-mentioned (meth) acrylic acid alkyl ester monomer, a reactive functional group-containing α, β-unsaturated monomer and a copolymerizable α, β-unsaturated monomer. At least one selected from

A first mixture containing a 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 is from 2,000 to 1,000,000, preferably 1
0000 to 400,000, more preferably 20,000
00 to 200,000. If the number average molecular weight is lower than the above range, properties as a block polymer may not be exhibited, and if it is higher, the viscosity may be high and handleability may be deteriorated.

The acrylic block polymer has a plurality of polymer portions having two or more different compositions when formed through a first polymerization step and a second polymerization step described below,
By repeating the second polymerization step two or more times, it is possible to have a plurality of polymer parts having three or more different compositions. In the first polymerization step, the first α, β is obtained starting from the mercapto group of the polyvalent mercaptan.
Performing radical polymerization of unsaturated monomers. By the radical polymerization, a product in which one end of a polymer portion having one composition is bonded to one or a plurality of sulfur residues of a mercapto group in each molecule of the polyvalent mercaptan 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 addition step, the second mixture is obtained by adding the monomer mixture to the reaction mixture obtained by the radical polymerization performed earlier. This monomer mixture is capable of forming a polymer that is incompatible with the high glass transition point type polymer,
Contains acrylic acid alkyl ester monomers. here,
“Incompatible” means that the tangent loss (tan δ, storage modulus G ′ and loss modulus G ”are measured in the dynamic viscoelasticity measurement of the polymer.
Ratio: tan δ = G ″ / G ′) means that the number of curve peaks is 2. That is, the number of curve peaks is caused by the polymer of the monomer mixture containing the alkyl (meth) acrylate monomer. The peak appears on the low temperature side, and the peak due to the high glass transition point polymer having a glass transition point of 273 K or higher appears on the high temperature side, while “compatible” means that two curve peaks of the tangent loss are used. Means one peak without separation.

[0051] The second mixture may optionally be, for example,
Organic solvents such as 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 Good. The organic solvent may be a single solvent or a mixed solvent. The second α, β-unsaturated monomer used in the addition step contains a (meth) acrylic acid alkyl ester monomer as an essential component and, if necessary, contains a reactive functional group-containing α, β- It may further include an unsaturated monomer. The second α, β-unsaturated monomer may or may not further comprise a reactive functional group-containing α, β-unsaturated monomer, and may be an α-β-unsaturated monomer copolymerizable with these monomers. , Β-unsaturated monomers.

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 a pressure-sensitive adhesive. Things are given, 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 is exemplified. The amount of the (meth) acrylic acid alkyl ester monomer used to obtain the acrylic block polymer is 68 to 68% based on the total amount of the second α, β-unsaturated monomer used. 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 second α, β-unsaturated monomer used for obtaining the acrylic block polymer may further comprise a reactive functional group-containing α, β-unsaturated monomer, if necessary. Can be included. 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. Examples thereof include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, and anhydride. At least one selected from the group consisting of unsaturated carboxylic acids such as maleic acid and maleic acid. When a carboxyl group-containing α, β-unsaturated monomer is used to obtain an acrylic block polymer, the carboxyl group-containing α, β
The amount of unsaturated monomer is, for example, 0.1 to 10% by weight, preferably 2 to 8% by weight, based on the total amount of the second α, β-unsaturated monomer used. . If 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
If the amount is more than 100% by weight, the cohesive strength becomes too high, 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. Examples thereof include 2-hydroxyethyl (meth) acrylate and ( Hydroxy group-containing polymerizable monomers such as 2-hydroxypropyl (meth) acrylate, 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: Hydroxyl-containing α, β-
When an unsaturated monomer is used, the amount of the hydroxyl group-containing α, β-unsaturated monomer is, for example, 0.1% based on the total amount of the second α, β-unsaturated monomer used. It is from 0.1 to 2% by weight, preferably from 0.1 to 1% by weight. Hydroxyl group-containing α, β-
When the amount of the unsaturated monomer is less than 0.01% by weight, the crosslinking point becomes insufficient, so that the crosslinking density is insufficient and the cohesive strength may be insufficient. Or the cohesive strength becomes too high, and the adhesive strength may decrease.

The second α, β-unsaturated monomer used to obtain the acrylic block polymer contains a (meth) acrylic acid alkyl ester monomer as an essential component,
Regardless of whether it further contains a reactive functional group-containing α, β-unsaturated monomer, α, β copolymerizable with these monomers
It may further include a β-unsaturated monomer. The copolymerizable α, β-unsaturated monomer is not particularly restricted but includes, for example, aromatic α, β-unsaturated monomers such as styrene and α-methylstyrene; vinyl acetate, vinyl propionate Vinyl esters such as N-vinylpyrrolidone,
N-group-containing α, β-unsaturated monomers such as acryloylmorpholine; α, β-unsaturated nitriles such as (meth) acrylonitrile; and unsaturated amides such as (meth) acrylamide and N-methylolacrylamide. At least one selected from Copolymerizable α, β used to obtain acrylic block polymer
The amount of the unsaturated monomer is, for example, 0 to 20% by weight based on the total amount of the second α, β-unsaturated monomer used in consideration of the balance between tackiness and cohesion and cohesion. %. When the amount of the copolymerizable α, β-unsaturated monomer exceeds 20% by weight, the acrylic block polymer becomes hard,
Adhesive strength may decrease.

The composition of the second α, β-unsaturated monomer used to obtain the acrylic block polymer has a Tg of 2 from the balance of tack and adhesion.
It is preferable to use them in combination so as to be 00K to 240K. The amount of the second α, β-unsaturated monomer used to obtain the acrylic block polymer is a total of 100% by weight of the monomer and the first α, β-unsaturated monomer. Parts by weight, for example, 60 to 95 parts by weight, preferably 70 to 95 parts by weight.
90 parts by weight. If the amount of the second α, β-unsaturated monomer exceeds 95 parts by weight, that is, if the amount of the first α, β-unsaturated monomer is less than 5 parts by weight, the migration of the plasticizer will occur. In some cases, the cohesive strength is significantly reduced. Also, the second α,
If the amount of the β-unsaturated monomer is less than 60 parts by weight, that is, if the amount of the first α, β-unsaturated monomer exceeds 40 parts by weight, the physical properties of the pressure-sensitive adhesive may be greatly reduced. is there.

In the second polymerization step, radical polymerization of the monomers contained in the second mixture is performed. If necessary, unreacted monomer components can be removed from the reaction mixture containing the product of the previous radical polymerization, or
The unreacted monomer components may be left without being removed and used for the subsequent radical polymerization. Subsequent radical polymerization is performed starting from all or a part of the remaining mercapto groups in the polyvalent mercaptan. A product in which one end of a polymer portion having another composition is bonded to the sulfur residue of the mercapto group serving as the starting point is obtained. This product may have unreacted mercapto groups.
In this case, by repeating the second polymerization step twice, a polymer portion having a third different composition is introduced, and by repeating the second polymerization step three times, the third and fourth polymerization steps are performed.
, A polymer portion having a different composition can be introduced as the number of repetitions of the second polymerization step is increased.

The first and second polymerization steps for producing the acrylic block polymer can be carried out by a conventional radical polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like. In order to obtain an inexpensive polymer, a bulk polymerization method containing no extra volatile components is preferred. The polymerization temperature is preferably from 30 to 200 ° C., more preferably from 100 to 15 ° C. which enables stable bulk polymerization without using a polymerization initiator.
0 ° C. A conventional radical polymerization initiator (for example, 2,2'-) is used for polymerization for producing an acrylic block polymer.
Azo-based polymerization initiators such as azobisisobutyronitrile and 2,2'-azobiscyclohexanecarbonitrile; and peroxide-based polymerization initiators such as benzoyl peroxide) can be used. 1 / of polyvalent mercaptan
3 or less, 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 that gives the block polymer, and the efficiency of the block polymer production is increased. In addition, polymerization stability of bulk polymerization, which is an industrially inexpensive production method, deteriorates, a runaway reaction occurs, and in the worst case, there is a risk of explosion.

As a procedure for producing the acrylic block polymer, radical polymerization of the first α, β-unsaturated monomer is performed starting from the mercapto group of the polyvalent mercaptan, and the polymerization rate is 50% or more. Preferably, when the content becomes 80% or more, an acrylic block polymer can be obtained by adding and polymerizing a monomer mixture containing a (meth) acrylic acid alkyl ester monomer. The reason why the polymerization rate of the previously performed radical polymerization is set to 50% or more is that the properties of the polymer forming the block are obtained even if the next polymerization is performed without removing the unsaturated monomer remaining after the polymerization. Is to be as different as possible. Therefore, after the first polymerization step, the remaining unsaturated monomer can be volatilized and removed. Further, if each radical polymerization is terminated by adding a polymerization inhibitor, it is possible to prevent a polymer portion having a different composition from being connected to the tip of the generated polymer portion by a subsequent radical polymerization.

If the polymerization is carried out in more stages as described above, an acrylic block polymer comprising a combination of three or more 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 block polymer can be dissolved and / or dispersed. For example, aromatic hydrocarbons such as toluene and xylene And 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. Or a mixed solvent of two or more. The amount of the organic solvent is, for example, 100 to 400 parts by weight, preferably 150 to 35 parts by weight based on 100 parts by weight of the acrylic polymer.
0 parts by weight. 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 composition for a pressure-sensitive adhesive of the present invention is characterized in that when the acrylic block polymer is prepared using a monomer mixture containing an α, β-unsaturated monomer having a reactive functional group, 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. 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 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 multifunctional 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 crosslinking agent include acetylacetone, methyl acetoacetate, acetoacetate and the like 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 1 with respect to 100 parts by weight of the acrylic block polymer.
0 parts by weight, preferably 0.5 to 5 parts by weight. 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 strength may be insufficient. Too long, and the 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, coumarone type, coumarone indene type, styrene resin type, xylene resin type, phenol resin type, petroleum resin type, etc. Tackifier. These can be used alone or in combination of two or more. The amount of the tackifier is, for example, 5 to 100 parts by weight, preferably 1 to 100 parts by weight of the acrylic block polymer.
0 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 a filler, pigment, diluent, antioxidant, It may contain at least one additive selected from the group consisting of an ultraviolet absorber, an ultraviolet stabilizer and the like. The composition for a pressure-sensitive adhesive of the present invention is used, for example, for producing the following pressure-sensitive adhesive product by a method described below. This adhesive product has aspect α
It is provided with a pressure-sensitive adhesive layer for soft PVC formed using the pressure-sensitive adhesive composition of (1) to (7), and is applied to a soft polyvinyl chloride molded product.

The pressure-sensitive adhesive layer for soft PVC is formed, for example, as follows. (A) a cross-linking step of applying the composition for an adhesive of the present invention containing an acrylic block polymer and an organic solvent in which the acrylic block polymer is dissolved and / or dispersed to a substrate to be dried and cross-linked; To form a pressure-sensitive adhesive layer for soft PVC. Each monomer mixture used in the polymerization step for producing the acrylic block polymer may further contain a reactive functional group-containing α, β-unsaturated monomer. 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 object to be coated and drying, thereby cross-linking the acrylic block polymer. 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 block polymer is performed by, for example, room temperature crosslinking that is allowed to stand at room temperature for one week or more, or high temperature accelerated crosslinking that promotes the reaction in a constant temperature room at 40 to 50 ° C. When the acrylic block polymer is made using a monomer mixture containing a reactive functional group-containing α, β-unsaturated monomer, a functional group capable of reacting with the reactive functional group of the acrylic polymer At least 2
It is cross-linked by the reaction with the cross-linking agent. The crosslinking agent used here is the same as the crosslinking agent used in the pressure-sensitive adhesive composition. The conditions for crosslinking may be appropriately set according to the crosslinking agent used.

The pressure-sensitive adhesive product may further include a separator attached to one or both surfaces of the pressure-sensitive adhesive layer for soft PVC. The pressure-sensitive adhesive product has two pressure-sensitive adhesive layers for soft PVC, and a support sandwiched between the pressure-sensitive adhesive layers for soft PVC, and adhered to one surface of the pressure-sensitive adhesive layer for soft PVC opposite to the support. A separator may be further provided. The adhesive product may further include a separator attached to one surface of the soft PVC adhesive layer, and a base material attached to the other surface of the soft PVC adhesive layer. The substrate is, for example, a flexible polyvinyl chloride substrate.

As the separator, for example, a paper base material whose surface is directly subjected to release treatment with a release agent such as silicone, a laminated film obtained by laminating a polyethylene film on the back surface of this release treated paper base material, polyester
A plastic film such as polyethylene or polypropylene is used. The pressure-sensitive adhesive product is, for example, a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a double-sided tape, or the like; or a soft pressure-sensitive adhesive sheet, a soft pressure-sensitive adhesive tape, a soft pressure-sensitive adhesive label, or the like. The adhesive product is produced by the following method, but the production method is not limited. On one surface of the separator, the pressure-sensitive adhesive composition of the present invention is applied with a composition containing at least an acrylic block polymer, a cross-linking agent and an organic solvent, and after drying, the pressure-sensitive adhesive formed on the separator surface The layer is overlaid on one side of another separator, a substrate described below or a support described below, and transferred under pressure (for example, at a pressure of 1 to 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 sides of the support, a pressure-sensitive adhesive composition of the present invention, which is coated with at least an acrylic block polymer, a crosslinking agent and an organic solvent, is dried, and the obtained pressure-sensitive adhesive layer is obtained. Attach a separator to cover.

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 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. The adhesive product can be such that the support is a flexible polyvinyl chloride molded article.

[0072]

EXAMPLES Examples of the present invention and comparative examples outside the scope of the present invention will be shown below, but the present invention is not limited to the following examples. In the following, “%” means “% by weight” and “parts” means “parts by weight”. In addition, the number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) were determined by gel permeation chromatography (GPC) in terms of polystyrene. The glass transition temperature (Tg) was measured using a differential scanning calorimeter "DSC-7" manufactured by Perkin Elmer.
Determined by

The amount of mercapto groups consumed was determined by the Elleman method (colorimetric method) using a dimethylformamide solvent. (Example 1) Methyl methacrylate (MMA) was placed in a 1.5-liter four-neck flask equipped with a Max Blend blade (manufactured by Sumitomo Heavy Industries, Ltd.) equipped with a nitrogen inlet tube, a dropping funnel, a thermometer, and a cooling tube. ), 3 parts of hydroxyethyl acrylate (HEA) and 230 parts of ethyl acetate were added, and the mixture was heated to 83 ° C under a nitrogen atmosphere. After the internal temperature reaches 83 ° C., 2.5 parts of dipentaerythritol hexakisthioglycolate, a hexavalent mercaptan, 2,2 ′
-Azobis (2-methylbutyronitrile) (ABN-
E, manufactured by Nippon Hydrazine Industry Co., Ltd.) (0.8 parts) and 10 parts of ethyl acetate were added to initiate polymerization.

70 minutes and 100 minutes after the start of the polymerization, respectively, dipentaerythritol hexakisthioglycolate.
5 parts, 0.4 part of ABN-E and 5 parts of ethyl acetate were added. 140 minutes after the start of polymerization, the conversion of methyl methacrylate reached 83%, the number average molecular weight Mn of the produced polymer was 1.3 × 10 ⁴ , the molecular weight distribution (Mw / Mn) was 1.9,
Glass transition temperature was 90 ° C. From the determination of the mercapto group, 70 mol% of the mercapto group in the added dipentaerythritol hexakisthioglycolate was consumed. Therefore, the number of branches of the polymer portion (MMA / HEA) is 4.2 on average (6 × 0.7 =), and the number average molecular weight is (1.3 × 10 ⁴ /4.2≒)3, It turned out to be 100.

Subsequently, 738 parts of butyl acrylate, 12 parts of HEA, and 74 parts of ethyl acetate were added dropwise to the reaction solution from a dropping funnel.
0 parts were added dropwise over 2 hours. During this time, the internal temperature was 85 ° C. Ten minutes, 40 minutes, and 70 minutes after the completion of dropping, 0.2 parts of ABN-E and 5 parts of ethyl acetate were added, respectively. Inner temperature 8
After reacting at 5 ° C. for 90 minutes, the reaction was cooled to room temperature to complete the reaction. The polymerization rate was 100%. The obtained pressure-sensitive adhesive solution was a fluorescent white viscous liquid having a nonvolatile content of 50.1% and a viscosity of 3,500 cps at 25 ° C. For packaging tapes, dry coating thickness of 25 on PET film
It was applied to a thickness of μm and dried at 100 ° C. for 2 minutes. Table 1 shows the evaluation results of 180 ° peel, ball tack, holding power (stainless steel, cardboard), and cardboard sealability.

It was found that the pressure-sensitive adhesive of Example 1 had excellent holding power without using a cross-linking agent and was excellent as a pressure-sensitive adhesive for packaging tapes. 180 ° peel and ball tack were measured by the methods described above. Holding force is 25mm on stainless steel plate or cardboard plate
Attach the tape with an adhesive area of × 25 mm, press and reciprocate with a 2 kg roller once, adjust the temperature at a predetermined temperature (40 ° C., 80 ° C.) for 1 hour, and apply a load of 1 kg to drop it or 60 hours. The displacement (unit: mm) after one minute was measured and evaluated. Cardboard sealability is as follows: 1kg petroleum can (for 2 pieces) packing cardboard box and adhesive tape at specified temperature (5 ℃, 40 ℃)
And left in a constant temperature / humidity room set at 50 mm, sealed with a 50 mm width, pressed back and forth with a 1 kg roller on the side once, and cut with a cutter knife while leaving the side part 30 mm long.
After a time, peeling of the tape was observed.ハ indicates that no peeling occurred, and x indicates that peeling occurred.

(Comparative Example 1) A pressure-sensitive adhesive solution for comparison was obtained using the same apparatus as in Example 1, except that dipentaerythritol hexakisthioglycolate was not used. The obtained pressure-sensitive adhesive solution had a nonvolatile concentration of 4
It was a white viscous liquid having a viscosity of 11,000 cps at 9.5% and 25 ° C. For a packaging tape, apply on a PET film so that the dry coating thickness is 25 μm.
Dry at 0 ° C. for 2 minutes. Table 1 shows the evaluation results of 180 ° peel, ball tack, holding power (stainless steel, cardboard), and cardboard sealability.

(Comparative Example 2) Using the same apparatus as in Example 1, 289.5 parts of butyl acrylate, 9 parts of acrylic acid,
1.5 parts of HEA and 300 parts of ethyl acetate were added, and the temperature was raised to 83 ° C. in a nitrogen atmosphere. The polymerization was started by adding 2 parts of ABN-E and 10 parts of ethyl acetate. Ten minutes after the start of the polymerization, 675.5 parts of butyl acrylate, 21 parts of acrylic acid, 3.5 parts of HEA, 200 parts of ethyl acetate, and 500 parts of toluene were dropped from the dropping funnel over 3 hours. End of dripping 10
Minutes, 40 minutes, and 70 minutes later, 0.5 parts of ABN-E,
5 parts of ethyl acetate were added. After reacting at an internal temperature of 85 ° C. for 90 minutes, the reaction was terminated by cooling to room temperature. The conversion is 1
00%.

The obtained comparative pressure-sensitive adhesive had a nonvolatile content of 4
It was a transparent viscous liquid having a viscosity of 13,000 cps at 9.8% and 25 ° C. Number average molecular weight 3.2 × 10 ⁴ , Mw
/Mn=8.9. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[0080]

[Table 1]

The pressure-sensitive adhesive of Example 1 was excellent in all of holding power, ball tack, and cardboard sealing property. Comparative adhesives of Comparative Examples 1 and 2 were inferior to those of Example 1 in all physical properties except ball tack,
It could not be used as a packaging tape. In addition, in the test for holding power, the comparative pressure-sensitive adhesive had undergone cohesive failure and remained on the SUS plate. (Example 2) In the same apparatus as in Example 1, 147.5 parts of methyl methacrylate (MMA) and 1.5 parts of acrylic acid (AA) were used.
Parts, 2-hydroxyethyl acrylate (HEA) 1.0
And 140 parts of ethyl acetate, and the mixture was heated to 83 ° C. under a nitrogen atmosphere. After the internal temperature reached 83 ° C., 2 parts of pentaerythritol tetrakisthioglycolate (PETG), a tetravalent mercaptan, 0.6 parts of ABN-E, and 10 parts of ethyl acetate were added to initiate polymerization.

90 minutes and 120 minutes after the start of the polymerization, respectively.
1 part of ETG, 0.3 part of ABN-E and 5 parts of ethyl acetate were added. 160 minutes after the start of the polymerization, the conversion of MMA reached 85%, and the number average molecular weight of the produced polymer was 1.8 × 1
O ⁴ , molecular weight distribution (Mw / Mn) was 2.0, and glass transition temperature was 91 ° C. From the determination of the mercapto group, 74 mol% of the mercapto group in the added PETG was consumed. Therefore, the number of branches of the polymer part (MMA / AA / HEA) is 2.96 on average (4 × 0.74 =), and the number average molecular weight is (1.8 × 10 ⁴ /2.96≒)6. , 100
It turned out to be.

Subsequently, 666 parts of butyl acrylate (BA), 170 parts of 2-ethylhexyl acrylate (2EHA), 8.5 parts of AA, HEA
5.5 parts and 500 parts of ethyl acetate were added dropwise over 2.5 hours. During this time, the internal temperature was 85 ° C. After completion of the dropwise addition, 500 parts of toluene were added over 20 minutes, and ABN-
0.6 part of E and 5 parts of ethyl acetate were added. After reacting at 85 ° C. for 3 hours, the mixture was cooled, and Pencel C (polymerized rosin ester manufactured by Arakawa Chemical Co., having a softening point of 117 to 12) was used as a tackifier.
7 ° C.) and 100 parts of stiberite ester 10 (hydrogenated rosin ester manufactured by Rika Hercules, softening point 71-78)
(C) 100 parts together with 300 parts of toluene to obtain an adhesive solution having a solid content of 45.2% and a viscosity of 5,600 cps.

One part of Coronate L (an isocyanate compound manufactured by Nippon Polyurethane Co., 75% solids) is mixed with 100 parts of the solid content of the pressure-sensitive adhesive solution, and the thickness after drying on a release paper is 75 μm. And apply 10 sheets
After drying at 0 ° C. for 3 minutes, transfer to both sides of the non-woven fabric for 15 minutes.
A 0 μm double-sided tape was produced. After curing at 23 ° C. for 7 days, physical properties were measured. The 180 ° peel and the holding power were measured by a conventional method with 50 μm thick PET stuck on one side. Table 2 shows the results. 0.4mm rebound resistance
A 20mm thick, 180mm long aluminum plate is stuck on one side of the double-sided tape, and a 2kg roller is reciprocated on a 3mm thick, 25mm wide, 200mm long polystyrene plate, and after 30 minutes 190mm The lifting (mm) from both ends when the polystyrene was bent and deformed and left at 40 ° C. for 24 hours was measured. The smaller the value, the better the resilience resistance. Excellent rebound resistance is useful in applications where flexibility is required.

The pressure-sensitive adhesive of Example 2 was excellent in 180 ° peel, holding power and rebound resistance, and was found to be excellent as a double-sided pressure-sensitive adhesive tape. (Comparative Example 3) BA787 parts,
196.5 parts of 2EHA, 10 parts of AA, 6.5 parts of HEA,
300 parts of a mixture of 1460 parts consisting of 460 parts of ethyl acetate and 200 parts of ethyl acetate were charged. The temperature was raised to 83 ° C. under a nitrogen atmosphere, and 1.2 parts of ABN-E and 10 parts of ethyl acetate were added to initiate polymerization. Fifteen minutes after the start of the polymerization, the remaining 1,160 parts of the mixture was added dropwise over 2.5 hours. During this time, polymerization was continued at 85 ° C.

After the dropwise addition, 500 parts of toluene was added over 20 minutes, and 1.2 parts of ABN-E and 5 parts of ethyl acetate were further added. After reacting at 85 ° C for 3 hours, it was cooled,
As a tackifier, 100 parts of Pencel C and 100 parts of stevelite ester 10 were added together with 450 parts of toluene to give a solid content of 42.5% and a viscosity of 5,800 cps (25 ° C.).
Was obtained. 100 parts of the solid content of this adhesive solution was mixed with 1 part of Coronate L to prepare a double-sided tape in the same manner as in Example 2-2. Example 2-2 had a sufficient holding power, but in Comparative Example 3, it fell after 60 minutes, and it was considered that coronate L was insufficient.
Thus, 2 parts of Coronate L was added and re-evaluated. Table 2 shows the results.

Although the balance between 180 ° peel, holding power and resilience resistance is generally difficult to achieve, Coronate L
One part was insufficient in holding power and repulsion resistance, and the Coronate L2 part was insufficient in repulsion resistance.

[0088]

[Table 2]

Next, Examples and Comparative Examples in which the pressure-sensitive adhesive composition of the present invention is a high solid solvent type pressure-sensitive adhesive will be described. (Example 3) 195 parts of phenyl methacrylate (PhMA) and acrylic acid (AA) 2 were added to the same apparatus as in Example 1.
, 3 parts of HEA and 190 parts of ethyl acetate, and the mixture was heated to 83 ° C under a nitrogen atmosphere. After the internal temperature reaches 83 ° C, 4
The polymerization was initiated by adding 9 parts of pentaerythritol tetrakisthioglycolate, a bivalent mercaptan, 0.8 parts of 2,2'-azobisvaleronitrile (AIBN) and 10 parts of ethyl acetate.

70 minutes and 100 minutes after the start of the polymerization, pentaerythritol tetrakisthioglycolate 4.5, respectively.
, 0.4 parts of AIBN and 5 parts of ethyl acetate. 140 minutes after the start of the polymerization, the conversion of phenyl methacrylate is 80
% And the number average molecular weight of the produced polymer is 0.5 × 10
^{4. The} molecular weight distribution (Mw / Mn) was 1.8 and the glass transition temperature was 83 ° C. From the determination of the mercapto group, 70 mol% of the mercapto group in the added pentaerythritol tetrakisthioglycolate was consumed. Therefore,
The number of branches of the polymer portion (PhMA / AA / HEA) was 2.8 on average (4 × 0.7 =), and the number average molecular weight was (0.5 × 10 ⁴ /2.8≒) 1800. It turned out to be. Subsequently, BA78 was added to the reaction solution from a dropping funnel.
0 parts, 8 parts of AA, 12 parts of HEA and 150 parts of ethyl acetate were added dropwise over 2 hours. During this time, the internal temperature was 85 ° C.

Ten minutes, 40 minutes, and 70 minutes after the completion of the dropping, 0.2 parts of AIBN and 5 parts of ethyl acetate were added, respectively.
After reacting at an internal temperature of 85 ° C. for 90 minutes, toluene 175
The reaction was terminated by adding parts and cooling. Polymerization rate is 10
It was 0%. The obtained pressure-sensitive adhesive solution had a nonvolatile content of 6
It was a 5.0% fluorescent white viscous liquid having a viscosity of 8,800 cps at 25 ° C. Number average molecular weight 1.9 × 10 ⁴ ,
Mw / Mn = 4.5. To this adhesive solution, 1.68 parts (the amount based on 100 parts of the solid content of the adhesive solution) of Coronate L55E (a polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd .: solid content of 55%) was mixed.
It was applied on a PET film so as to have a dry coating thickness of 25 μm, and was dried at 100 ° C. for 2 minutes. Then 23
Cured at ℃ for 7 days.

Table 3 shows the evaluation results of 180 ° peel, ball tack and holding power (stainless steel) of the obtained pressure-sensitive adhesive tape. The pressure-sensitive adhesive of Example 3 had a high non-volatile content of 65%, a viscosity at 25 ° C. of 8,800 cps, was excellent in mechanical coating properties, and was excellent in the balance of adhesive properties. Example 4 An adhesive solution was obtained by repeating the same operation as in Example 3 except that the polymerizable monomer component, the polyvalent mercaptan, and the solvent were changed to those shown in Table 3. Table 3 shows the evaluation results.

Comparative Example 4 A curing agent was added to the comparative adhesive obtained in Comparative Example 2 to evaluate the adhesive properties. Table 3 shows the results. Although the adhesive properties are excellent, the viscosity is 13,000 despite the low nonvolatile content of 49.8%.
It was as high as cps. (Comparative Example 5) BA22 was prepared using the same apparatus as in Example 1.
9.5 parts, 2-ethylhexyl acrylate (2EHA)
60 parts, 3 parts of AA, 4.5 parts of HEA, 7 parts of octyl thioglycolate, and 190 parts of ethyl acetate were added, and the mixture was heated to 83 ° C. under a nitrogen atmosphere. AIBN 2 parts, ethyl acetate 10
And the polymerization was started.

10 minutes after the start of the polymerization, BA5 was dropped from the dropping funnel.
30 parts, 2EHA 140 parts, AA7 parts, HEA10.5
And 150 parts of ethyl acetate were added dropwise over 3 hours. 10 minutes, 40 minutes, and 70 minutes after the end of the dropping, AIBN 0.
Two parts and 5 parts of ethyl acetate were added. After reacting at an internal temperature of 85 ° C. for 90 minutes, 175 parts of toluene was added and cooled, and the reaction was terminated. The polymerization rate was 100%. The obtained pressure-sensitive adhesive solution was a transparent viscous liquid having a nonvolatile content of 64.5% and a viscosity of 9,900 cps at 25 ° C. The number average molecular weight was 2.1 × 10 ⁴ , and Mw / Mn was 3.5.

The adhesive obtained in Comparative Example 5 was crosslinked with Coronate L55E in the same manner as in Example 3, and the adhesive properties were compared. The comparative pressure-sensitive adhesive was the same amount of Coronate L55 as in Example 3.
In E, the holding power was insufficient, so about 4 times the amount was used. As a result, the 180 ° peel became extremely small, and the adhesive was inflexible and brittle. (Comparative Example 6) In Example 3, octyl thioglycolate (TGO) was used in place of 18 parts of pentaerythritol tetrakisthioglycolate which is a tetravalent mercaptan.
The same operation as in Example 3 was repeated except that 7 parts were used to obtain a pressure-sensitive adhesive solution for comparison. Table 3 shows the physical property values. Since the thermoplastic addition polymer of this pressure-sensitive adhesive does not have a block structure, poly (PhMA / AA / HEA) and poly (PhMA / BA / AA / HEA) are separated too much, resulting in insufficient adhesion and cohesion. It was something.

[0096]

[Table 3]

1) PMMA macromonomer Mn = 2,0
002) The viscosity was measured at 25 rpm at 30 rpm with a B-type viscometer # 4. 3) Coronate L55E based on 100 parts of adhesive solids
Is added. 4) The probe tack has a load of 100 g, a contact time of 1 second,
It was measured under the conditions of 5 mmφ and 23 ° C. Hereinafter, the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition of aspects α to γ, using these pressure-sensitive adhesive compositions, examples of pressure-sensitive adhesive products of aspects δ to ε with drawings explain. FIG. 1 is a cross-sectional view of one example of an adhesive product.
This adhesive product is a double-sided adhesive tape 5,
It has a soft PVC adhesive layer 2 and a separator 3.

The pressure-sensitive adhesive layer 2 for flexible PVC is formed of an acrylic cross-linked copolymer (crosslinked from an acrylic block polymer) 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 (for example, a film, a sheet, a tape, or a wallpaper).

FIG. 2 is a sectional view of still another example of the adhesive product. This pressure-sensitive adhesive product is a coreless double-sided pressure-sensitive adhesive tape (double-sided pressure-sensitive adhesive tape without a support) 6, which has a pressure-sensitive adhesive layer 2 for soft PVC and a separator 3. The pressure-sensitive adhesive layer 2 for soft PVC is formed of an acrylic cross-linked copolymer (cross-linked acrylic block polymer) produced by a production method including a step of drying and cross-linking the pressure-sensitive adhesive composition of the present invention. Include as main ingredient. The separator 3 is, for example, release paper, and is attached to both surfaces of the soft PVC adhesive layer 2 so as to cover both surfaces. FIG. 3 is a sectional view of still another example of the adhesive product. This pressure-sensitive adhesive product has a pressure-sensitive adhesive layer 2 for soft PVC, a separator 3, and a base material 4.

The pressure-sensitive adhesive layer 2 for soft PVC is formed of an acrylic cross-linked copolymer (crosslinked from an acrylic block polymer) prepared 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 still another example of the pressure-sensitive adhesive product. This adhesive product
It has a soft PVC adhesive layer 2, a separator 3, and a substrate 7.

The pressure-sensitive adhesive layer 2 for flexible PVC is formed of an acrylic cross-linked copolymer (crosslinked from an acrylic block polymer) prepared 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 substrate 7 is made of, for example, amimi foil; polyethylene,
Examples include sheets of polyolefin such as polypropylene. Hereinafter, specific examples according to another embodiment of the present invention will be described together with comparative examples, but the present invention is not limited to the following examples. Further, in the following Examples and Comparative Examples,
“Parts” and “%” represent “parts by weight” and “% by weight”, respectively.

[Production of pressure-sensitive adhesive composition] Example A1- 200 parts of styrene and 1.0 part of pentaerythritol tetrakisthioglycolate (PETG) were mixed with a thermometer, a stirrer, a Max Blend blade (Sumitomo Heavy Industries, Ltd. Co., Ltd.),
The mixture was charged into a 2 liter four-necked flask equipped with an inert gas inlet tube, a reflux condenser and a dropping funnel, and was subjected to polymerization at 140 ° C. under a nitrogen atmosphere. Three hours later, 760 parts of butyl acrylate and 40 parts of acrylic acid were added all at once. After a while, when the internal temperature rose, it was found that the reaction mixture became cloudy and the second-stage polymerization was started. The polymerization rate after reacting at the reflux temperature of the monomers for 5 hours was 99.4%. The residual monomer was removed under reduced pressure, and 1,300 parts of toluene was added to the reaction mixture to dissolve the solid, and the solid content was 36.4.
%, And a solution of an acrylic copolymer having a viscosity of 17,200 cps was obtained.

Examples A2 to A3 and Comparative Example A1-The procedure of Example A1 was repeated except that the reaction raw materials and / or reaction conditions were changed as shown in Table 4.
A solution of an acrylic copolymer having a solid content, viscosity, and weight average molecular weight shown in Table 4 was obtained.

[0104]

[Table 4]

Example B1- Coronate L55E (a polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd .: solid content 55) was added to the solution of the acrylic copolymer (solid content 100 parts) obtained in Example A1.
%) Was mixed to prepare a pressure-sensitive adhesive composition. -Examples B2 to B6 and Comparative Examples B1 to B2-The amounts of the solution of the acrylic copolymer and the amount of the crosslinking agent are shown in Tables 5 to 6.
The procedure of Example B1 was repeated, except that the composition was changed as shown in Table 2, to prepare a pressure-sensitive adhesive composition. -Example C1-The pressure-sensitive adhesive composition obtained in Example B1 was coated on one surface of release paper (manufactured by Fujimori Industries Co., Ltd .: 70K-818T / EF) so that the thickness after drying was 50 µm. It was dried at 100 ° C. for 2 minutes and cured at 23 ° C. for 7 days. Then 5
A soft polyvinyl chloride sheet (with release paper) is placed on one side of a soft polyvinyl chloride sheet having a thickness of 0 μm (manufactured by Okamoto Corporation) and pressurized. Obtained.

Examples C2 to C6 and Comparative Examples C1 to C
2- The procedure of Example C1 was repeated except that the pressure-sensitive adhesive composition was changed as shown in Tables 5 and 6, to produce a soft PVC pressure-sensitive adhesive sheet. Comparative Example D1- A commercially available double-sided tape for soft PVC (a double tack tape # 577 manufactured by Sekisui Chemical Co., Ltd.) was prepared for comparison. -Comparative Example D2- 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 D3- 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. In the table, TETRAD-C is 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane manufactured by Mitsubishi Gas Chemical Company, Ltd. With respect to the flexible PVC adhesive sheet and the double-sided tape obtained in the examples and comparative examples, the holding power and the adhesive power were measured according to JIS-Z0237 (1991), and the results are shown in Tables 5 to 6.

The holding force was 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 heating was promoted. 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.

[0110]

[Table 5]

[0111]

[Table 6]

As shown in Tables 4 to 6, the examples of the present invention are based on the molecular weight of the obtained polymer (acrylic graft polymer or acrylic block polymer) suitable for a single-sided adhesive sheet, Suitable for adhesive tape, but excellent in initial adhesive strength, suppresses decrease in cohesive force even when plasticizer migrates from soft PVC due to accelerated heating, adhesive strength is considerably higher than comparative examples 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) K) Methyl methacrylate: 378 (K) Vinyl acetate: 305 (K) Acrylonitrile: 398 (K) Styrene: 373 (K)

[0113]

(Equation 1)

[0114]

According to the present invention, there is provided a solvent-based pressure-sensitive adhesive composition comprising a thermoplastic polyaddition having a polyvalent mercaptan portion and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion. A first polymer portion comprising a high glass transition point type polymer having a glass transition point of 273 K or more, comprising a polymer having a glass transition point of at least 273 K, and a second polymer having an organic solvent in which the thermoplastic addition polymer is dissolved and / or dispersed. The united part is 273K
It is composed of a low glass transition type polymer having a glass transition point of less than 20,000 cps or less at 25 ° C., so that it has excellent adhesiveness and heat resistance, and especially when no cross-linking agent is used, the adhesive with time can be used. Less likely to cause a drop or change in force.

The solvent-based pressure-sensitive adhesive composition of the present invention may be prepared using a pressure-sensitive adhesive tape (kraft paper, uniaxially oriented polypropylene (OP
P), cellophane, soft vinyl chloride resin, polyethylene,
Substrates such as cloth, PET, foam, and non-woven fabric are used. Adhesive labels (paper, synthetic paper, soft vinyl chloride resin, OPP, cellophane, polyethylene, PET, etc.) for cardboard sealing, light packaging seal, protection, train, paint masking, double-sided adhesive etc. Used as a base material), medical adhesive products (adhesive plasters, patches,
It is useful for applications such as transdermal patches. When the non-volatile content of the solvent-based pressure-sensitive adhesive composition of the present invention is 60 to 80% by weight, it is excellent in tackiness and heat resistance, and can be used as a high-solid solvent-type pressure-sensitive adhesive capable of coping with environmental problems, energy saving, and speeding up the line. Useful.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one example of an adhesive product.

FIG. 2 is a cross-sectional view of one example of an adhesive product.

FIG. 3 is a cross-sectional view of one example of an adhesive product.

FIG. 4 is a cross-sectional view of one example of an adhesive product.

[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

Claims (3)

[Claims] 1. A solvent-based pressure-sensitive adhesive composition comprising a thermoplastic addition polymer and an organic solvent in which the thermoplastic addition polymer is dissolved and / or dispersed, wherein the thermoplastic addition polymer is a polyvalent mercaptan And a polymer having a star-shaped block structure having a polyvalent mercaptan portion, which is the remaining portion from which the proton of the mercapto group is dissociated, and a first polymer portion and a second polymer portion radially extending from the polyvalent mercaptan portion. And its viscosity at 25 ° C. is 20,000 cps
And wherein the first polymer portion is composed of a high glass transition point type polymer having a glass transition point of 273K or more, and the second polymer portion is a low glass transition point having a glass transition point of less than 273K. A solvent-type pressure-sensitive adhesive composition, comprising a type polymerization. 2. The solvent-based pressure-sensitive adhesive composition according to claim 1, wherein the polymer having a star block structure is a polymer produced by the following production method. Polyvalent mercaptan and 273K
A preparation step of preparing a first mixture containing a first α, β-unsaturated monomer capable of producing a high glass transition point polymer having the above glass transition point, and a mercapto of the polyvalent mercaptan A radical polymerization of the first α, β-unsaturated monomer starting from the group to obtain a reaction mixture;
A polymerization step and an addition step of adding a second α, β-unsaturated monomer to the reaction mixture to obtain a second mixture capable of producing a low glass transition point type polymer having a glass transition point of less than 273K. A second polymerization step of performing radical polymerization of the monomer contained in the second mixture. 3. The method according to claim 1, wherein the nonvolatile content is 60 to 80% by weight.
The solvent-based pressure-sensitive adhesive composition according to claim 1.