JP6349802B2 - Adhesive composition - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition that can be used in various fields including the manufacture of electronic devices such as portable electronic terminals, and the fixing of interior and exterior members of automobiles and buildings.

  Adhesives are used in the production scenes of various products such as electronic devices and automobiles. For example, in the case of the production of electronic devices, fixing or filling two or more casings constituting the electronic device. Used for fixing batteries, circuit boards, etc.

  Examples of the pressure-sensitive adhesive that can be used in the above-described scene include a polymer obtained by copolymerizing at least an alkyl acrylate ester, a hydroxyl group-containing monomer, vinyl acetate, and a carboxyl group-containing monomer, and the carboxyl group in the polymer. A pressure-sensitive adhesive composition is known in which the weight ratio of the group-containing monomer is 0.01 to 1.0 part by weight, contains a crosslinking agent, and has a ball tack of 12 to 30 (for example, patents). Reference 1).

  On the other hand, the usage of electronic devices such as portable electronic terminals is diverse, and as the pressure-sensitive adhesive, for example, even when a strong impact is applied to the electronic devices, etc. There is a demand from the industry to achieve both a level of impact resistance that does not cause peeling.

  However, it is technically difficult to achieve both an excellent peel adhesion and the impact resistance at a higher level, and pressure-sensitive adhesives having the above-mentioned properties at a level required by the industry have not yet been found. The fact was not.

JP 2011-168658 A

  The problem to be solved by the present invention is to provide an adhesive composition having both excellent peel adhesive strength and excellent impact resistance.

  The present inventors can solve the above-mentioned problems by using a pressure-sensitive adhesive composition containing an acrylic polymer (A) having a specific amount of hydroxyl groups among pressure-sensitive adhesive compositions containing an acrylic polymer. I found it.

  That is, this invention is an adhesive composition containing the acrylic polymer (A) which has a hydroxyl group, Comprising: The said acrylic polymer (A) is 0 (meth) acrylic monomer (a1) which has a hydroxyl group. The present invention relates to a pressure-sensitive adhesive composition characterized by being obtained by polymerizing a monomer component containing 0.01 mass% to 0.1 mass%.

  The pressure-sensitive adhesive composition of the present invention can achieve both excellent peel adhesion and excellent impact resistance. For example, manufacturing electronic devices such as portable electronic terminals, fixing automobile parts, fixing interior and exterior of buildings, etc. It can be used in various scenes including

  The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition containing an acrylic polymer (A) having a hydroxyl group, wherein the acrylic polymer (A) is a (meth) acrylic monomer having a hydroxyl group (a1). ) Is obtained by polymerizing a monomer component containing 0.01% by mass to 0.1% by mass.

As the acrylic polymer (A), an acrylic polymer having a very specific amount of hydroxyl groups is used in order to obtain a pressure-sensitive adhesive composition having both excellent peel adhesion and excellent impact resistance.
Here, instead of the acrylic polymer (A), a single (meth) acrylic monomer (a1) having a hydroxyl group with respect to the total amount of the monomer component is contained in an amount exceeding 0.1% by mass. A pressure-sensitive adhesive composition containing an acrylic polymer obtained by polymerizing a monomer component may not be able to achieve both excellent peel adhesion and excellent impact resistance.
The (meth) acrylic monomer (a1) having a hydroxyl group is preferably used in an amount of 0.01% by mass or more and less than 0.1% by mass with respect to the total amount of the monomer component. It is more preferable to use in the range of mass% to 0.08 mass% in order to obtain a pressure-sensitive adhesive composition that achieves both excellent peel adhesion and excellent impact resistance.
Further, as the acrylic polymer (A), it is preferable to use an acrylic polymer having an acid value in the range of 1 to 50 in order to impart even more excellent peel adhesion and excellent impact resistance. More preferably, those having an acid value in the range of 10 to 50 are used, more preferably those having an acid value in the range of 25 to 40. The acid value is preferably an acid value derived exclusively from a carboxyl group.
Moreover, as said acrylic polymer (A), it is preferable to use what has an aliphatic cyclic structure, in order to make the further excellent peel adhesive force and the outstanding impact resistance compatible.
Examples of the aliphatic cyclic structure include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a propylcyclohexyl group, a tricyclo [5,2,1,0,2,6] decyl group, and a bicyclo [ 4,3,0] -nonyl group, tricyclo [5,3,1,1] dodecyl group, propyltricyclo [5,3,1,1] dodecyl group, norbornene group, isobornyl group, dicyclopentanyl group, Examples include an adamantyl group, and among them, a cyclohexyl group, a norbornene group, an isobornyl group, and an adamantyl group are preferable in order to obtain a pressure-sensitive adhesive composition having both excellent peel adhesive strength and excellent impact resistance.
Moreover, as the acrylic polymer (A), a pressure-sensitive adhesive composition that has both excellent peel adhesion and excellent impact resistance can be obtained by using a polymer having a weight average molecular weight of 800,000 or more. It is preferable to obtain, more preferably one having a weight average molecular weight in the range of 800,000 to 2,200,000, more preferably one having a weight average molecular weight in the range of 1,000,000 to 2,200,000. It is further preferable for obtaining a pressure-sensitive adhesive composition having both adhesive strength and excellent impact resistance. In addition, the said weight average molecular weight is a weight average molecular weight in standard polystyrene conversion measured with a gel permeation chromatograph (GPC).

The molecular weight is measured by the GPC method using a Tosoh Corporation GPC apparatus (HLC-8329GPC) and converted to polystyrene.
Sample concentration: 0.5% by mass (THF solution)
Sample injection volume: 100 μl
Eluent: THF
Flow rate: 1.0 ml / min Measurement temperature: 40 ° C
This column: TSKgel GMHHR-H (20) 2 Guard column: TSKgel HXL-H
Detector: differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (manufactured by Tosoh Corporation)

  As said acrylic polymer (A), it is preferable to use what has a glass transition temperature of -25 degrees C or less, and it is much more preferable to use what has a glass transition temperature of -45 degreeC--30 degreeC. It is more preferable to obtain a pressure-sensitive adhesive composition that achieves both excellent peel adhesion and excellent impact resistance.

  The acrylic polymer (A) is preferably contained in an amount of 5% by mass to 50% by mass, and preferably 10% by mass to 45% by mass, based on the total amount of the pressure-sensitive adhesive composition. It is more preferable for maintaining the property.

Examples of the (meth) acrylic monomer (a1) having a hydroxyl group used in a specific amount when producing the acrylic polymer (A) include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. , 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyhexyl (meth) acrylate, 6-hydroxyhexyl (meth) acryl, 8-hydroxyoctyl (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and the like can be used.
Among them, as the (meth) acrylic monomer (a1) having a hydroxyl group, 4-hydroxybutyl (meth) acrylate is preferably used, and 4-hydroxybutyl acrylate is more excellent. It is more preferable for obtaining a pressure-sensitive adhesive composition having both peel adhesion and excellent impact resistance.

  Moreover, as said acrylic polymer (A), the monomer component containing the (meth) acrylic monomer (a1) which has the said hydroxyl group, and the (meth) acrylic monomer (a2) which has an acid group is superposed | polymerized. It is more preferable to use what is obtained by obtaining a pressure-sensitive adhesive composition that has both excellent peel adhesive strength and excellent impact resistance.

  Examples of the (meth) acrylic monomer (a2) having an acid group include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, (anhydrous) itaconic acid, and (anhydrous) maleic acid. , Fumaric acid, crotonic acid and the like can be used. Among them, it is more preferable to use acrylic acid or methacrylic acid in order to obtain a pressure-sensitive adhesive composition that has both excellent peel adhesive strength and excellent impact resistance.

At that time, the (meth) acrylic monomer (a1) having a hydroxyl group is preferably in the range of 0.01% by mass to 0.1% by mass, preferably 0.02%, based on the total amount of the monomer components. The amount of the (meth) acrylic monomer (a2) used in the range of mass% to 0.08 mass% and having the acid group is preferably 1 mass% to 15 mass with respect to the total amount of the monomer components. %, More preferably in the range of 1% by mass to 10% by mass, still more preferably in the range of 1% by mass to 7% by mass, and particularly preferably in the range of 1% by mass to 6.5% by mass. .

In addition, when the acrylic polymer (A) is produced, a (meth) acrylic monomer having an aliphatic cyclic structure as the monomer component in introducing an aliphatic cyclic structure into the acrylic polymer. It is preferable to use the body.
As the (meth) acrylic monomer having an aliphatic cyclic structure, cyclohexyl (meth) acrylate or the like is preferably used, and cyclohexyl acrylate is more preferably used.
The (meth) acrylic monomer having an aliphatic cyclic structure is used in the range of 0.5% by mass to 30% by mass with respect to the total amount of the monomer component. It is preferable to obtain a pressure-sensitive adhesive composition having both excellent impact resistance and more preferable to use in the range of 4% by mass to 25% by mass.
As a monomer component that can be used in the production of the acrylic polymer (A), other monomers can be used as necessary in addition to the above-described monomers.
Examples of the other monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, and isobutyl (meth). Acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) Use alkyl (meth) acrylates such as acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. It is possible.
Among the above-mentioned other monomers, among them, n-butyl acrylate and 2-ethylhexyl acrylate can be used to obtain a pressure-sensitive adhesive composition that has both excellent peel adhesion and excellent impact resistance. Moreover, it is preferable.

  The said alkyl (meth) acrylate which can be used as said other monomer is used in the range of 50 mass%-98 mass% with respect to the whole quantity of the monomer component used for manufacture of the said acrylic polymer (A). It is preferable to use in the range of 60% by mass to 95% by mass, and it is preferable to use in the range of 70% by mass to 94% by mass with excellent peel adhesion and excellent impact resistance. It is preferable for obtaining a compatible pressure-sensitive adhesive composition.

  Examples of other monomers that can be used for the production of the acrylic polymer (A) include acrylic monomers having an amide group, acrylic monomers having an amino group, and acrylic monomers having an imide group. An acrylic monomer having a nitrogen atom such as can be used.

  Examples of the acrylic monomer having an amide group include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, diacetoneacrylamide and the like can be used.

  Examples of the acrylic monomer having an amino group include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like. .

  As the acrylic monomer having an imide group, for example, cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, itaconimide and the like can be used.

  Examples of the other monomers include those other than those described above, such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth). Acrylic monomers containing sulfonic acid groups such as acrylate, (meth) acryloyloxynaphthalenesulfonic acid, sodium vinyl sulfonate, 2-hydroxyethylacryloyl phosphate group-containing acrylic monomers, acrylonitrile, methacrylonitrile, etc. Cyano group-containing monomers, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, glycidyl group-containing acrylic monomers such as allyl glycidyl ether, vinyl acetate, vinyl propionate, vinyl laurate, styrene, Rosuchiren, chloromethylstyrene, alpha-methyl styrene, other substituted styrenes, may also be used methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether.

The acrylic polymer (A) can be produced, for example, by supplying the monomer components and radically polymerizing them in the presence of an organic solvent. Specifically, in the acrylic polymer (A), the monomer component, the polymerization initiator, and the organic solvent are preferably mixed and stirred at a temperature of 40 ° C. to 90 ° C. to cause radical polymerization. Can be manufactured by. The monomer component may be supplied in a lump or may be supplied separately.
Examples of the polymerization initiator include peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, 2,2′-azobis (2-methylbutyronitrile), and 2,2′-azobis. -(2-aminodipropane) dihydrochloride, 2,2'-azobis- (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1, An azo compound such as 1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} can be used. The amount of the polymerization initiator used is preferably in the range of 0.01% by mass to 5% by mass with respect to the total amount of the monomer components.

As the pressure-sensitive adhesive composition of the present invention, it is preferable to use a pressure-sensitive adhesive composition containing a tackifying resin in order to achieve both excellent peel adhesion and excellent impact resistance.
Examples of the tackifying resin include a rosin tackifying resin, a polymerized rosin tackifying resin, a polymerized rosin ester tackifying resin, a rosin phenol tackifying resin, a stabilized rosin ester tackifying resin, and a disproportionated rosin ester. A tackifier resin, a hydrogenated rosin ester tackifier resin, a terpene tackifier resin, a terpene phenol tackifier resin, a petroleum resin tackifier resin, a (meth) acrylate tackifier resin, and the like can be used.
Especially, as said tackifying resin, 2 or more types chosen from the group which consists of polymeric rosin ester type tackifying resin, disproportionated rosin ester type tackifying resin, petroleum type tackifying resin, and terpene phenol type tackifying resin are included. Use in combination is preferable in terms of having excellent compatibility with the specific acrylic polymer (A) and achieving both excellent peel adhesion and excellent impact resistance.

  The tackifying resin is preferably used in the range of 10 to 50 parts by mass and in the range of 20 to 40 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). It is more preferable for imparting even better peel adhesion and impact resistance.

Moreover, as said adhesive composition, when forming the adhesive layer provided with the further outstanding cohesion force, it is preferable to use what contains a crosslinking agent.
As said crosslinking agent, an isocyanate type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent, an aziridine type crosslinking agent etc. can be used, for example. Especially, as said crosslinking agent, it is easy to mix and use the said acrylic polymer (A) or its solution manufactured previously, and to use the crosslinking agent which can advance a crosslinking reaction rapidly. Specifically, it is more preferable to use an isocyanate crosslinking agent or an epoxy crosslinking agent.

  Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, and their trimethylolpropane adducts, triphenylmethane isocyanate, and the like. Can be used. Especially, as said isocyanate type crosslinking agent, it is preferable to use tolylene diisocyanate, these trimethylol propane adducts, triphenylmethane isocyanate, etc.

  As an index of the degree of crosslinking of the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition containing the cross-linking agent, the value of the gel fraction for measuring the insoluble content after the pressure-sensitive adhesive layer is immersed in toluene for 24 hours is Can be mentioned. The gel fraction is preferably in the range of 20% by mass to 60% by mass, more preferably in the range of 30% by mass to 50% by mass, and in the range of 40% by mass to 50% by mass. However, it is more preferable for imparting even more excellent peel adhesion and the like.

In addition, the said gel fraction can be measured by the method shown below.
The pressure-sensitive adhesive composition is coated on one side of an arbitrary release liner so that the thickness after drying is 50 μm, dried at 100 ° C. for 3 minutes, and aged at 40 ° C. for 2 days. Form. A sample cut into a 50 mm square is used as a sample.
Next, after measuring the mass (G1) of the sample, the sample is immersed in a toluene solution at 23 ° C. for 24 hours. The toluene-insoluble part of the sample after the immersion is separated by filtration through a 300 mesh wire net, and the mass (G2) of the residue after drying at 110 ° C. for 1 hour is measured, and the gel fraction is determined according to the following formula: .
Gel fraction (mass%) = (G2 / G1) × 100

As the pressure-sensitive adhesive composition, in addition to those described above, those containing other components can be used as necessary.
Examples of the other components include plasticizers, softeners, antioxidants, flame retardants, glass and plastic fibers, balloons and beads, fillers such as metals, metal oxides, and metal nitrides, pigments and dyes, and the like. Additives such as colorants, leveling agents, thickeners, water repellents and antifoaming agents can be used.

Moreover, as an adhesive composition of this invention, when providing favorable coating workability | operativity, it is preferable to use what contains a solvent. As said solvent, aqueous media, such as an organic solvent and water, etc. are mentioned, for example.
Examples of the organic solvent include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, hexane, acetone, cyclohexanone, 3-pentanone, acetonitrile, propionitrile, isobutyronitrile, valeronitrile, dimethyl sulfoxide, dimethylformamide, and the like. be able to.

The pressure-sensitive adhesive composition of the present invention can be applied to the surface of any adherend and used. Moreover, the adhesive composition of this invention can be used for formation of the adhesive layer which comprises the adhesive tape which can be used for fixation of various members.
Examples of the adhesive tape include a non-woven base material, a foam base material, a resin film base material, etc., one side or both sides of the pressure-sensitive adhesive tape provided with the pressure-sensitive adhesive layer, and a so-called base material-less structure composed only of the pressure-sensitive adhesive layer. The adhesive tape is mentioned.
As the pressure-sensitive adhesive layer, one having a thickness of 10 μm to 150 μm is preferably used, and one having a thickness of 20 μm to 100 μm is more preferably used.

The pressure-sensitive adhesive tape of the present invention can be produced, for example, by applying the pressure-sensitive adhesive composition on one side or both sides of a base material using a roll coater, a die coater or the like and drying it. In addition, the pressure-sensitive adhesive tape previously forms the pressure-sensitive adhesive layer by applying the pressure-sensitive adhesive on the surface of the release liner using a roll coater and the like, and then drying the pressure-sensitive adhesive layer. It can be manufactured by a transfer method in which both surfaces are bonded.
Moreover, the said base material-less adhesive tape can be manufactured by apply | coating the said adhesive to the surface of a release liner previously using a roll coater etc., and drying.

As a base material constituting the adhesive tape, for example, a resin base material such as a polyester film, a polyethylene film, a polypropylene film, a plastic film such as a polyvinyl chloride film, a non-woven base material, a foam base material, cloth, paper, etc. are used. can do.
As the resin base material, one subjected to corona treatment, anchor coat treatment, or the like can be used for improving the anchoring property of the pressure-sensitive adhesive layer.

As the substrate, it is more preferable to use a substrate having a thickness of 1 μm to 500 μm from the viewpoint of providing excellent workability of the tape and excellent followability to the adherend.
Moreover, the said adhesive tape may have another layer as needed other than the said base material and an adhesive layer.
Examples of the other layer include a laminated layer such as a polyester film, a light shielding layer, a light reflection layer, a metal layer, and the like in order to provide, for example, dimensional stability of the adhesive tape and good tensile strength and suitability for rework. Can be mentioned.

Since the pressure-sensitive adhesive tape of the present invention has a further excellent peel adhesion and impact resistance, it can be used, for example, for fixing a narrow member having a sticking site limited to a width of 5 mm or less. .
The narrow member is often used as a member in industrial applications such as electronic terminals such as mobile phones, automobiles, building materials, OA, and home appliance industries.
Specific examples of the member include two or more casings and lens members that constitute an electronic terminal.
Articles such as electronic terminals to which two or more cases and lens members are fixed using the adhesive tape of the present invention are not easily disassembled by an impact such as dropping, and have excellent waterproof properties.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Preparation Example 1] Method for Producing Acrylic Polymer (A-1) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 80.94 parts by mass of n-butyl acrylate, 2-ethylhexyl acrylate 5 Mass parts, 10 parts by mass of cyclohexyl acrylate, 4 parts by mass of acrylic acid, 0.06 parts by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate were charged, and the temperature was raised to 72 ° C. while blowing nitrogen under stirring. .
Next, 2 parts by mass of a 2,2′-azobis (2-methylbutyronitrile) solution previously dissolved in ethyl acetate (solid content: 0.1% by mass) was added to the mixture, and the mixture was stirred at 72 ° C. After holding for 4 hours, it was held at 75 ° C. for 5 hours.
Next, the mixture was diluted with 98 parts by mass of ethyl acetate and filtered through a 200 mesh wire mesh to obtain an acrylic polymer (A-1) solution (nonvolatile content: 40% by mass) having a weight average molecular weight of 1,600,000.
In addition, the said weight average molecular weight is a weight average molecular weight in standard polystyrene conversion measured by a gel permeation chromatograph (GPC), and was measured with the following method.
The measurement of the molecular weight by GPC method is a standard polystyrene conversion value measured using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation.
Sample concentration: 0.5% by mass (tetrahydrofuran solution)
Sample injection volume: 100 μl
Eluent: THF (tetrahydrofuran)
Flow rate: 1.0 ml / min Measurement temperature: 40 ° C
This column: TSKgel GMHHR-H (20) 2 Guard column: TSKgel HXL-H
Detector: differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (manufactured by Tosoh Corporation)

[Preparation Example 2] Production method of acrylic polymer (A-2) The amount of 4-hydroxybutyl acrylate used was changed from 0.06 parts by mass to 0.02 parts by mass, and the amount of n-butyl acrylate used The acrylic polymer (A-2) solution (non-volatile content: 40% by mass) having a weight average molecular weight of 1,640,000 was prepared in the same manner as in Preparation Example 1, except that 80.94 parts by mass was changed from 80.94 parts by mass to 80.98 parts by mass. Obtained.

[Preparation Example 3] Production method of acrylic polymer (A-3) The amount of 4-hydroxybutyl acrylate used was changed from 0.06 parts by weight to 0.1 parts by weight, and the amount of n-butyl acrylate used. The acrylic polymer (A-3) solution having a weight average molecular weight of 16.2 million (nonvolatile content: 40% by mass) was prepared in the same manner as in Preparation Example 1 except that 80.94 parts by mass was changed from 80.94 parts by mass to 80.9 parts by mass. Obtained.

[Preparation Example 4] Production method of acrylic polymer (A-4) Preparation example, except that the cyclohexyl acrylate is not used and the amount of 2-ethylhexyl acrylate is changed from 5 parts by mass to 15 parts by mass 1 was used to obtain an acrylic polymer (A-4) solution (nonvolatile content: 40% by mass) having a weight average molecular weight of 1.32 million.

[Preparation Example 5] Production method of acrylic polymer (A-5) The amount of cyclohexyl acrylate used is changed from 10 parts by mass to 20 parts by mass, and the amount of n-butyl acrylate used is from 80.94 parts by mass. An acrylic polymer (A-5) solution (nonvolatile content: 40% by mass) having a weight average molecular weight of 1,840,000 was obtained in the same manner as in Preparation Example 1, except that the amount was changed to 70.94 parts by mass.

[Preparation Example 6] Method for Producing Acrylic Polymer (A-6) The amount of cyclohexyl acrylate used is changed from 10 parts by weight to 25 parts by weight, and the amount of n-butyl acrylate used is from 80.94 parts by weight. The acrylic polymer (A-6) solution having a weight average molecular weight of 163,000 (A-6) (nonvolatile content: 40 mass) in the same manner as in Preparation Example 1, except that the amount is changed to 70.94 parts by mass and 2-ethylhexyl acrylate is not used. %).

[Preparation Example 7] Method for Producing Acrylic Polymer (A-7) The amount of acrylic acid used is changed from 4 parts by weight to 2 parts by weight, and the amount of n-butyl acrylate used is from 80.94 parts by weight. An acrylic polymer (A-7) solution having a weight average molecular weight of 1,640,000 (nonvolatile content: 40 mass) in the same manner as in Preparation Example 1 except that the content is changed to 97.94 parts by mass and 2-ethylhexyl acrylate is not used. %).

[Preparation Example 8] Production method of acrylic polymer (A-8) The amount of acrylic acid used is changed from 4 parts by mass to 6 parts by mass, and the amount of n-butyl acrylate used is from 80.94 parts by mass. An acrylic polymer (A-8) solution having a weight average molecular weight of 1,640,000 (nonvolatile content: 40 mass) in the same manner as in Preparation Example 1 except that the content is changed to 93.94 parts by mass and 2-ethylhexyl acrylate is not used. %).

[Preparation Example 9] Production method of acrylic polymer (A-9) The amount of 2,2′-azobis (2-methylbutyronitrile) solution used is from 2 parts by mass (solid content: 0.1% by mass) to 1 mass. An acrylic polymer (A-8) solution (non-volatile content 40% by mass) having a weight average molecular weight of 1.780,000 was obtained in the same manner as in Preparation Example 1 except that the content was changed to parts (solid content 0.05% by mass). .

[Preparation Example 10] Production method of acrylic polymer (A-10) The amount of 2,2′-azobis (2-methylbutyronitrile) solution used is from 2 parts by mass (solid content: 0.1% by mass) to 10 masses. An acrylic polymer (A-10) solution (nonvolatile content 40% by mass) having a weight average molecular weight of 810,000 was obtained in the same manner as in Preparation Example 1, except that the content was changed to parts (solid content 0.5% by mass). .

[Comparative Preparation Example 1] Method for producing acrylic polymer (B-1) The amount of 4-hydroxybutyl acrylate used was changed from 0.06 parts by mass to 0.15 parts by mass, and n-butyl acrylate was used. Except for changing the amount from 80.94 parts by mass to 80.85 parts by mass, an acrylic polymer (B-1) solution having a weight average molecular weight of 16.2 million (nonvolatile content: 40% by mass) in the same manner as in Preparation Example 1. Got.

[Comparative Preparation Example 2] Production method of acrylic polymer (B-2) The amount of 4-hydroxybutyl acrylate used was changed from 0.06 parts by weight to 0.2 parts by weight, and n-butyl acrylate was used. Except for changing the amount from 80.94 parts by mass to 80.8 parts by mass, the acrylic polymer (B-2) solution having a weight average molecular weight of 16.3 million (nonvolatile content 40% by mass) in the same manner as in Preparation Example 1. Got.

[Comparative Preparation Example 3] Method for Producing Acrylic Polymer (B-3) The amount of 4-hydroxybutyl acrylate used was changed from 0.06 parts by weight to 0 parts by weight, and the amount of n-butyl acrylate used was changed. An acrylic polymer (B-3) solution having a weight average molecular weight of 1.6 million (nonvolatile content: 40% by mass) was obtained in the same manner as in Preparation Example 1, except that the amount was changed from 80.94 parts by mass to 81 parts by mass.

[Example 1]
In a container, 100 parts by mass of the acrylic polymer (A-1) solution, 10 parts by mass of polymerized rosin ester-based tackifier resin D-125 (manufactured by Arakawa Chemical Industries) and disproportionated rosin-based tackifier resin A- A mixture was obtained by mixing and stirring 100 parts by mass (100 Arakawa Chemical Industries, Ltd.).
Next, Vernock D-40 (manufactured by DIC Corporation, trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by mass, nonvolatile content 40% by mass) as a crosslinking agent with respect to 100 parts by mass of the mixture 1 After adding 4 parts by mass and stirring and mixing so as to be uniform, an adhesive (P-1) was obtained by filtering through a 100 mesh wire net.

[Example 2]
A pressure-sensitive adhesive (P-2) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-2) solution was used instead of the acrylic polymer (A-1) solution.

[Example 3]
A pressure-sensitive adhesive (P-3) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-3) solution was used instead of the acrylic polymer (A-1) solution.

[Example 4]
A pressure-sensitive adhesive (P-4) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-4) solution was used instead of the acrylic polymer (A-1) solution.
However, Example 4 is a reference example.

[Example 5]
A pressure-sensitive adhesive (P-5) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-5) solution was used instead of the acrylic polymer (A-1) solution.

[Example 6]
A pressure-sensitive adhesive (P-6) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-6) solution was used instead of the acrylic polymer (A-1) solution.

[Example 7]
A pressure-sensitive adhesive (P-7) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-7) solution was used instead of the acrylic polymer (A-1) solution.

[Example 8]
A pressure-sensitive adhesive (P-8) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-8) solution was used instead of the acrylic polymer (A-1) solution.

[Example 9]
A pressure-sensitive adhesive (P-9) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-9) solution was used instead of the acrylic polymer (A-1) solution.

[Example 10]
A pressure-sensitive adhesive (P-10) was obtained in the same manner as in Example 1 except that the acrylic polymer (A-10) solution was used instead of the acrylic polymer (A-1) solution.

[Comparative Example 1]
A pressure-sensitive adhesive (Q-1) was obtained in the same manner as in Example 1, except that the acrylic polymer (B-1) solution was used instead of the acrylic polymer (A-1) solution.

[Comparative Example 2]
A pressure-sensitive adhesive (Q-2) was obtained in the same manner as in Example 1 except that the acrylic polymer (B-2) solution was used instead of the acrylic polymer (A-1) solution.

[Comparative Example 3]
A pressure-sensitive adhesive (Q-3) was obtained in the same manner as in Example 1 except that the acrylic polymer (B-3) solution was used instead of the acrylic polymer (A-1) solution.

The gel fraction described in the table was measured by the method shown below.
The pressure-sensitive adhesive composition is coated on one side of an arbitrary release liner so that the thickness after drying is 50 μm, dried at 100 ° C. for 3 minutes, and aged at 40 ° C. for 2 days. Form. A sample cut into a 50 mm square was used as a sample.
Next, after measuring the mass (G1) of the sample, the sample is immersed in a toluene solution at 23 ° C. for 24 hours. The toluene-insoluble matter of the sample after the immersion is separated by filtering through a 300 mesh wire mesh, and the mass (G2) of the residue after drying at 110 ° C. for 1 hour is measured, and the gel fraction is obtained according to the following formula. It was.
Gel fraction (mass%) = (G2 / G1) × 100

[Measurement method of 180 ° peel adhesive strength]
The pressure-sensitive adhesive layer is coated on the surface of the release liner using a bar coater so that the thickness of the pressure-sensitive adhesive layer after drying is 50 μm, and dried at 80 ° C. for 3 minutes to produce a pressure-sensitive adhesive layer. did.
Next, the adhesive layer is attached to one side of a 25 μm thick polyethylene terephthalate substrate, cured for 72 hours in an environment of 40 ° C., and then cut into a rectangle having a width of 20 mm and a length of 120 mm. Was made.
Next, in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH, the adhesive tape is affixed to a stainless steel plate, and the upper surface of the adhesive tape is reciprocated once using a 2 kg roller. The test piece 1 in which the adhesive tape and the stainless steel plate were pressure-bonded was prepared by allowing to stand for 1 hour in an environment with a humidity of 50% RH.
Next, using a Tensilon peel tester, the strength when the adhesive tape is peeled off in the 180 ° direction at a peel speed of 300 mm / min with the stainless steel plate constituting the test piece fixed horizontally is measured. did.

[Impact resistance evaluation method]
The pressure-sensitive adhesive layer is coated on the surface of the release liner using a bar coater so that the thickness of the pressure-sensitive adhesive layer after drying is 50 μm, and dried at 80 ° C. for 3 minutes to produce a pressure-sensitive adhesive layer. did. Next, the said adhesive layer was affixed on both surfaces of the 25-micrometer-thick polyethylene terephthalate base material, and was cured for 72 hours in a 40 degreeC environment. Next, the adhesive tape was cut to prepare two rectangular adhesive tapes having a width of 2 mm and a length of 20 mm.
Next, two rectangular adhesive tapes were attached in parallel to an acrylic plate having a thickness of 2 mm, a width of 25 mm, and a length of 50 mm at a position where the interval in the width direction was 45 mm.
Next, an acrylic plate having a thickness of 2 mm, a width of 25 mm, and a length of 50 mm different from the above is applied to the adhesive tape application surface, and the upper surface of the adhesive tape is reciprocated once using a 2 kg roller, Test pieces 2 were prepared by allowing them to stand in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours.
The stainless steel drop measurement jig (total mass 150 g) with the metal weight and the test piece 2 were attached using a double-sided adhesive tape having a width of 25 mm and a length of 50 mm. The patch obtained above was continuously dropped onto the concrete surface at intervals of 10 cm to 10 cm in height (5 times per step), and the height when peeling or breakage of the tape was observed on the test piece was measured.
A: After dropping from a height of 60 cm, the adhesive tape did not peel off.
○: After dropping from a height of 50 cm, the adhesive tape did not peel off.
X: Peeling of the adhesive tape occurred after dropping from a height of 40 to 50 cm.
XX: Peeling of the adhesive tape occurred after dropping from a height of less than 40 cm.

Claims (4)

A pressure-sensitive adhesive composition containing an acrylic polymer (A) having a hydroxyl group and a crosslinking agent,
The acrylic polymer (A) has a (meth) acrylic monomer (a1) having an aliphatic cyclic structure and a (meth) acrylic monomer (a1) having a hydroxyl group. In the range of 0.5% to 30% by weight and a monomer component containing 1% to 7% by weight of the (meth) acrylic monomer (a2) having a carboxyl group is polymerized. A pressure-sensitive adhesive composition characterized by being obtained.   The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic polymer (A) has an acid value in the range of 1 to 50. The pressure-sensitive adhesive composition according to claim 1 or 2 , wherein the acrylic polymer (A) has a weight average molecular weight of 800,000 or more. Furthermore, it contains two or more selected from the group consisting of a polymerized rosin ester tackifier resin, a disproportionated rosin ester tackifier resin, a petroleum tackifier resin, and a terpene phenol tackifier resin. The pressure-sensitive adhesive composition according to any one of to 3 .