JPH09316417A - Acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having acid value index and softening point index each within a specified range, high in initial tack performance, retaining its tack performance to vinyl chloride resins with the lapse of time, and useful for e.g. pressure-sensitive adhesive tapes. SOLUTION: This pressure-sensitive adhesive composition comprises an acrylic copolymer consisting mainly of an alkyl (meth)acrylate, 200,000-1500,000 in weight-average molecular weight (MW) and 2-4 in the ratio of weight-average molecular weight to number-average molecular weight (Mn ): MW/Mn and a tackifying resin (e.g. disproportionated rosin), having an acid value index shown by formula I (AVi is the acid value of (i)th component tackifying resin; Wi is the weight fraction of (i)th component tackifying resin in the composition) of 2-25 and a softening point index shown by formula II [SPi is the softening point of (i)th component tackifying resin ( deg.K)] of 4.5-6.5.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape, and more specifically to an acrylic pressure-sensitive adhesive composition whose adhesive strength does not change with time even when a plasticizer or metal ions are introduced. The present invention relates to an adhesive tape obtained by laminating this on a vinyl chloride resin film substrate or a metal thin film laminated plastic film substrate containing a plasticizer and a metal stabilizer.

[0002]

2. Description of the Related Art Conventional acrylic pressure-sensitive adhesives have an alkyl (meth) acrylate as a main component monomer and, if necessary, have a crosslinking base such as (meth) acrylic acid for the purpose of enhancing heat resistance and holding power. Those mainly composed of a copolymer obtained by copolymerizing a vinyl monomer containing a carboxyl group have been used. However, when the acrylic pressure-sensitive adhesive is laminated on a vinyl chloride resin film containing a plasticizer to form a pressure-sensitive adhesive tape, or when the pressure-sensitive adhesive tape using the acrylic pressure-sensitive adhesive is applied to the surface of a vinyl chloride resin product containing a plasticizer. However, there has been a problem that the plasticizer gradually migrates into the acrylic pressure-sensitive adhesive layer, and the adhesive performance of the pressure-sensitive adhesive tape is significantly deteriorated over time.

The deterioration of the performance of the pressure-sensitive adhesive tape over time due to the migration of the plasticizer is caused by a decrease in the cohesive force of the pressure-sensitive adhesive layer, and many improvements have been proposed. For example, JP-A-53-94519 discloses that a decrease in cohesive force is suppressed by blending a reactive resol-type phenol resin with an acrylic adhesive, and JP-A-1-101384. Discloses that a decrease in cohesive force is suppressed by using a polyfunctional unsaturated monomer, a keto / enol tautomer, and a complex compound of a polyvalent metal as an acrylic pressure-sensitive adhesive.

However, the above-mentioned Japanese Patent Laid-Open No. 53-9451.
No. 9 and JP-A-1-101384, the acrylic pressure-sensitive adhesive is laminated on a vinyl chloride resin film substrate containing a plasticizer and a metal-based stabilizer to be used as a pressure-sensitive adhesive tape. However, even when it is adhered to an adherend made of a vinyl chloride resin containing a plasticizer and a metal stabilizer, the adhesive performance of the acrylic pressure-sensitive adhesive is deteriorated with time. Further, in place of a relatively low molecular weight plasticizer such as dioctyl phthalate (DOP) which is most frequently used as a plasticizer for vinyl chloride resins containing the above metal-based stabilizer, a high molecular weight compound having relatively low migration is used. Even when the polyester-based plasticizer is used, the adhesive performance of the pressure-sensitive adhesive layer also deteriorates with time.

Further, in an adhesive tape in which a metal thin film and an acrylic adhesive layer in which a vinyl monomer containing a carboxyl group is copolymerized are sequentially provided on one surface of a plastic film, the tape may be peeled from an end portion or may be adhered with time. There was a drawback that the performance decreased.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to obtain an acrylic resin which has a high initial adhesiveness and does not deteriorate the adhesiveness with time to a vinyl chloride resin containing a plasticizer and a metal stabilizer. A pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape using the same, and a metal thin film and a pressure-sensitive adhesive layer are sequentially laminated on one surface of a plastic film, the initial adhesive performance is high, and the adhesive performance over time does not decrease, and An object of the present invention is to provide an adhesive tape that is less likely to be peeled off from the end after being attached to a body.

[0007]

The invention according to claim 1 has an alkyl (meth) acrylate as a main component, a weight average molecular weight (Mw) of 200,000 to 1,500,000, and a weight average molecular weight (Mw) and a number average. An acrylic pressure-sensitive adhesive composition comprising an acrylic copolymer having a molecular weight (Mn) ratio (Mw / Mn) of 2 to 4 and a tackifying resin, having an acid value index described later of 2 to 25, In addition, the softening point index described later is 4.5.
The gist of the present invention is an acrylic pressure-sensitive adhesive composition characterized in that

The acrylic copolymer copolymerizes a monomer composition comprising more than 50% by weight of alkyl (meth) acrylate and less than 50% by weight of polar vinyl monomer copolymerizable with the above alkyl (meth) acrylate. It is obtained by The polar vinyl monomer is 50
This is because when the content is at least wt%, the glass transition temperature of the obtained acrylic copolymer becomes high, and it becomes difficult to obtain the initial adhesiveness and the low-temperature adhesiveness of the obtained acrylic pressure-sensitive adhesive composition.

The alkyl group of the alkyl (meth) acrylate preferably has 2 to 14 carbon atoms, and more preferably 4 to 12 carbon atoms. Examples of the alkyl (meth) acrylate include ethyl (meth) acrylate and n-
Propyl (meth) acrylate, isopropyl (meth)
Acrylate, n-butyl (meth) acrylate, se
Examples thereof include c-butyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate. You may use together.

As the polar vinyl monomer copolymerizable with the above-mentioned alkyl (meth) acrylate, for example, (meth)
Acrylic acid, itaconic acid, maleic acid (anhydrous), fumaric acid (anhydrous), etc., a carboxyl group-containing vinyl monomer, 2
-Hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, caprolactone-modified (meth) acrylate, polyoxyethylene-modified (meth) acrylate and other hydroxyl group-containing vinyl monomers, (meth ) Acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, (meth) acryloylmorpholine, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, etc. containing nitrogen Examples thereof include vinyl monomers and vinyl acetate.
Two or more of these may be used in combination.

The method for polymerizing the above-mentioned monomer composition containing an alkyl (meth) acrylate as a main component is not particularly limited. For example, solution polymerization, bulk polymerization, suspension polymerization, or other polymerization method may be used. Azo compounds such as butyronitrile, benzoyl peroxide, thermal polymerization initiators such as peroxides such as ammonium persulfate, redox polymerization initiators in which a reducing agent is combined with the above thermal polymerization initiators, methoxyacetophenone, benzyl dimethyl ketal Polymerization can be performed using a polymerization initiator such as an ultraviolet polymerization initiator. In particular, the solution polymerization method is suitable because an organic solvent is used during the polymerization, so that the acrylic resin can be uniformly mixed when the tackifying resin is added to the obtained acrylic copolymer.

In the above polymerization reaction, by adding a chain transfer agent, the obtained acrylic copolymer can be controlled to have a desired molecular weight. Examples of such a chain transfer agent include lauryl mercaptan and the like.

The molecular weight of the acrylic copolymer can be determined from the polystyrene equivalent molecular weight using a gel permeation chromatograph (GPC) method. The weight average molecular weight (Mw) of the acrylic copolymer is 200,000 to 15
0,000, preferably 200,000 to 1,200,000, more preferably 3
It is 50,000 to 700,000. When the Mw of the acrylic copolymer is less than 200,000, the cohesive force of the pressure-sensitive adhesive layer cannot be sufficiently obtained,
When the Mw of the acrylic copolymer is more than 1,500,000, the viscosity of the obtained pressure-sensitive adhesive becomes too high, and the productivity in the mixing, transporting and coating steps deteriorates.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic copolymer,
That is, the molecular weight distribution is 2 to 4, preferably 2 to 3.5. When the acrylic copolymer has a (Mw / Mn) of more than 4, the resulting adhesive layer has a poor balance between cohesive force and adhesive force, and the acrylic system has a (Mw / Mn) of less than 2 Copolymers are difficult and virtually impossible to produce.

The tackifying resin used in the invention of claim 1 has an acid value index (AP) of 2 to 25 as an acrylic pressure-sensitive adhesive composition after being added to an acrylic copolymer.
And the softening point index (SpP) is 4.5 to 6.5.
It is assumed that.

The acid value index (AP) of the tackifying resin is expressed by the following formula (1): acid value index (AP) = Σ (AVi × Wi) (1) [AVi: Acid value of tackifier resin of i-th component, Wi: Weight fraction of tackifier resin of i-th component in acrylic pressure-sensitive adhesive composition] Acid value and tackiness of each tackifier resin specified in JIS K 0070 It is the sum of the products of the weight fraction of the tackifying resin (% by weight of each tackifying resin relative to the total weight of the acrylic copolymer and the tackifying resin), and the acid groups of the tackifying resin present in the tackifier system. Is a parameter that represents the concentration of. When the acid value index (AP) is less than 2, the adhesiveness to a vinyl chloride resin containing a plasticizer and a metal stabilizer becomes poor,
Further, when the acid value index (AP) exceeds 25, it becomes difficult to obtain the cohesive force of the pressure-sensitive adhesive layer.

The softening point exponent (SpP) is as shown in the following equation (2): softening point exponent (SpP) = Σ (Wi / Spi) × 10000 (2) [Spi: i-th component Softening point (K) of tackifying resin, W
i: Weight fraction of tackifying resin as the i-th component in acrylic pressure-sensitive adhesive composition] Weight fraction of each tackifying resin (of each tackifying resin relative to the total amount of the weight of the acrylic polymer and tackifying resin) (Wt%) is multiplied by the softening point and multiplied by 10,000, and is a parameter showing the cohesive strength level of the whole pressure-sensitive adhesive, which is also correlated with the glass transition temperature of the whole pressure-sensitive adhesive (JE NIELSEN). Written by Shigeharu Onoki: "Mechanical properties of polymers and composites", page 16). When the softening point index (SpP) is less than 4.5, it becomes difficult to obtain the heat resistance of the pressure-sensitive adhesive layer, and when the softening point index (SpP) exceeds 6.5, the initial adhesive performance is And the adhesive performance at low temperatures is reduced.

The tackifying resin is not particularly limited as long as it satisfies the values of AP and SpP when added to the acrylic pressure-sensitive adhesive composition. And has a softening point of 75 to 200 ° C.
A rosin derivative or a phenol resin derivative that is is preferably used. As the rosin derivative having the above acid group,
Examples thereof include rosin that has been subjected to stabilization treatment such as partially disproportionated or disproportionated rosin, hydrogenated rosin, and polymerized rosin, and a rosin derivative modified with a dibasic acid such as maleic acid or fumaric acid.
Examples of the phenol resin derivative include rosin phenol resin, terpene phenol resin and xylene phenol resin. Further, a rosin monomer, a rosin dimer or a mixture thereof, a C5 or C9 petroleum resin, a pinene-based resin, a styrene-based tackifying resin containing no acid group may be used in combination. When combined with a non-tackifying resin, the tackifying resin as a whole, including these acid group-free tackifying resin,
It must satisfy the above expressions (1) and (2).

The acrylic pressure-sensitive adhesive composition of the invention of claim 1 comprises, in addition to the acrylic copolymer and the tackifying resin, a cross-linking agent for the acrylic copolymer, if necessary.
Additives such as a plasticizer, a softening agent, a filler and a coloring agent may be added. The above-mentioned cross-linking agent is different depending on a polar group serving as a cross-linking base, and for example, when the cross-linking base is a hydroxyl group, an aliphatic isocyanate cross-linking agent, an aromatic isocyanate cross-linking agent, and an alicyclic isocyanate cross-linking agent are used. When the cross-linking base point is a carboxyl group, epoxy-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, etc.

The acrylic pressure-sensitive adhesive composition of the invention of claim 1 may be used in a pressure-sensitive adhesive layer of a pressure-sensitive adhesive tape having a flexible film as a base material comprising a vinyl chloride resin, a plasticizer and a metal stabilizer. However, in addition to this, the adherend is a vinyl chloride resin containing a plasticizer and a metal-based stabilizer, such as an emblem sheet of an automobile emblem, a side molding, a skin of an automobile door trim, and a skin of an inner wall of an automobile. It is also suitably used for the pressure-sensitive adhesive layer of a pressure-sensitive adhesive tape or double-sided pressure-sensitive adhesive tape that is used as a product.

Next, the invention of claim 2 will be described in detail. According to the invention of claim 2, a pressure-sensitive adhesive layer made of the acrylic pressure-sensitive adhesive composition of the invention of claim 1 is provided on at least one surface of a flexible film made of a vinyl chloride resin, a plasticizer and a metal stabilizer. The gist is an adhesive tape characterized by.

Examples of the plasticizer include dioctyl phthalate, diisononyl phthalate, octyldecyl phthalate, diisodecyl phthalate, and other phthalic acid plasticizers; diisononyl adipate, diisodecyl adipate and other adipic acid plasticizers; Examples thereof include di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate, chlorinated paraffin, tri-2-ethylhexyl phosphate, epoxidized soybean oil and the like.

When the amount of the above-mentioned plasticizer added is small, it tends to be difficult to obtain sufficient flexibility as a base material for the pressure-sensitive adhesive tape, and when it is large, the amount of the plasticizer tends to be transferred to the pressure-sensitive adhesive layer and plasticized. Because it is in vinyl chloride resin 1
The amount is preferably 3 to 100 parts by weight with respect to 00 parts by weight.

The metal-based stabilizer is not particularly limited, but examples thereof include metal soap-based stabilizers, organic tin-based stabilizers, lead salt-based stabilizers and the like. Examples of the metal soap stabilizer include barium (Ba), zinc (Zn), magnesium (Mg), calcium (Ca), which are higher fatty acids such as stearic acid, lauric acid, and 2-ethylhexoic acid.
And metal salts such as Ba / Zn, Ca / Z
A composite metal soap-based stabilizer having a combination of n, Ca / Ba / Zn, Ca / Mg / Zn and the like is preferably used.

Examples of the above-mentioned organotin stabilizers include dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin mercaptide and the like. Specifically, "T-10"
"00BHJ" (manufactured by Koshosha) and the like are commercially available.

When the amount of the metal-based stabilizer added is small, it tends to be decomposed and deteriorated by the dehydrochlorination reaction.
Further, if it increases, crosslinking tends to proceed due to migration to the pressure-sensitive adhesive layer, and the adhesive performance tends to deteriorate, so 0.1 to 20 parts by weight is preferable with respect to 100 parts by weight of the vinyl chloride resin.

If necessary, the flexible film may contain a pigment, an ultraviolet absorber, an extender and the like. Examples of the pigment include carbon black, titanium white, quinacridone red and the like. Further, examples of the extender include calcium carbonate, magnesium carbonate, barium sulfate and the like.

As the method for producing the flexible film, for example, a sol-casting method in which a vinyl chloride resin organosol having the above-mentioned constitution dispersed in an organic solvent is coated and dried on a release paper and further cured by heating to form a sheet, Examples include, but are not limited to, a calendering method in which the material is heated and melted and molded into a sheet.

The thickness of the flexible film is not particularly limited, but when it is used as an adhesive tape, it is usually preferably 50 μm to 1 mm in view of workability.

As a method for laminating the acrylic pressure-sensitive adhesive composition of the invention of claim 1 on the flexible film, a direct coating method in which the acrylic pressure-sensitive adhesive composition is directly applied and dried, and a method in which it is applied and dried on a release paper are used. Later, there are transfer methods for transferring onto the flexible film, but the transfer method is not limited thereto. Further, for the purpose of improving the adhesion between the soft film and the acrylic pressure-sensitive adhesive layer, corona discharge treatment or the like can be performed on the film.

Next, the invention of claim 3 will be described in detail. The gist of the invention of claim 3 is a pressure-sensitive adhesive tape characterized in that a metal thin film and a pressure-sensitive adhesive layer made of the acrylic pressure-sensitive adhesive composition of the invention of claim 1 are sequentially provided on one surface of a plastic film. It is a thing.

Examples of the plastic film include polyolefin resin such as polyethylene resin and polypropylene resin, vinyl chloride resin, and polyester resin such as polyethylene terephthalate, which are formed into a film shape.

The thickness of the plastic film is not particularly limited, but when it is used as an adhesive tape, it is usually preferably 50 μm to 1 mm in view of its workability.

Examples of the metal to be laminated on the plastic film include silver and aluminum, and examples of the method for laminating the metal thin film include, for example, laminating metal foil by heat lamination, laminating metal foil by adhesive, and metal. Examples include stacking by vapor deposition, but the sputtering method and vapor deposition method are
It is more preferable because the metal thin film can be formed into an extremely thin film.

When the above-mentioned adhesive tape is attached to the bulk of a fluorescent lamp and used for improving the reflection efficiency, the thickness of the metal thin film is preferably 0.1 to 10 μm in order to obtain sufficient reflection efficiency. It is not limited.

As a method for laminating the acrylic pressure-sensitive adhesive composition of the invention of claim 1 on the metal thin film surface of the plastic film provided with the metal thin film, the acrylic pressure-sensitive adhesive composition is directly applied and dried. There are a coating method and a transfer method of coating and drying on a release paper, and then transferring onto the flexible film, but the present invention is not limited thereto.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. (Preparation of Solution of Acrylic Copolymer) Predetermined n-butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, 2-hydroxyethyl acrylate, vinyl acetate and lauryl mercaptan, and 80 parts by weight of ethyl acetate shown in Table 1 are added. A flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas inlet was charged, and the mixture was stirred, dissolved, and uniformly mixed.
Bubbling was performed for 0 minutes to remove oxygen existing in the reaction system. Then, the temperature was raised while stirring and nitrogen gas purging at the same time, and the temperature was maintained at 70 ° C., and a solution of 0.03 parts by weight of benzoyl peroxide dissolved in 1 part by weight of ethyl acetate was added over 3 hours with a dropping funnel. 70 after dropping
The temperature was kept at 0 ° C. and the reaction was carried out for 10 hours to obtain a solution of an acrylic copolymer.

(Measurement of Molecular Weight of Acrylic Copolymer) The obtained acrylic copolymer was subjected to gel permeation chromatograph (GPC) using standard polystyrene as a standard, tetrahydrofuran as an eluent, and a refractometer. The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) were measured according to the usual methods. The measurement results are also shown in Table 1.

[0039]

[Table 1]

(Tackifying Resin) The tackifying resins used in Examples and Comparative Examples of the present invention are shown below. Tackifying resin: A mixture of rosin monomer and polymerized rosin, manufactured by Arakawa Chemical Co., Ltd., trade name "Silva Tuck ST140"
(Acid value = 175, Softening point = 413 ° K) Tackifying resin: Disproportionated rosin, manufactured by Arakawa Chemical Co., Ltd., product name "Longis R" (acid value = 155, softening point = 348 ° K) Tackifying resin: Hydrogenated disproportionated rosin, manufactured by Arakawa Chemical Co., Ltd., trade name "KR-610" (acid value = 170, softening point = 358)
° K)

Tackifying resin: A mixture of rosin monomer and polymerized rosin esterified with a mixture of pentaerythritol and glycerin (containing about 9% by weight of unreacted rosin monomer and polymerized rosin), manufactured by Arakawa Chemical Co., Ltd. Name "Pencel D160" (acid value = 14, softening point = 433 ° K) Tackifying resin: a mixture of disproportionated rosin esterified with a mixture of glycerin and pentaerythritol (disproportionated rosin Leveled rosin about 10% by weight
Contained), manufactured by Arakawa Chemical Co., Ltd., trade name "Super Ester A1"
15 "(acid value = 17, softening point = 388 ° K) Tackifying resin: mixture of disproportionated rosin esterified with glycerin and disproportionated rosin (containing about 2% by weight of disproportionated rosin), Arakawa Chemical Co., Ltd., trade name “Super Ester S100” (acid value = 3, softening point = 373 °
K)

Tackifying resin: xylene phenol resin, manufactured by Mitsubishi Gas Chemical Co., Inc., trade name "Nikanol HP-16"
0 "(acid value = 25, softening point = 433 ° K) Tackifying resin: hydrogenated petroleum resin, manufactured by Arakawa Chemical Co., Ltd., trade name" Alcon P140 "(acid value = 0, softening point = 413 °)
K) Tackifying resin: C9 petroleum resin, manufactured by Mitsui Petrochemical,
Product name "FTR6100" (acid value = 0, softening point = 373
° K)

(Preparation of Acrylic Adhesive Composition Solution)
A predetermined solution of each of the acrylic copolymers shown in Table 2 in terms of solid content and a toluene solution of each tackifying resin (solid content: 45% by weight) were uniformly mixed, and toluene was added to obtain a solid content of 45% by weight. The concentration was adjusted, and to 100 parts by weight of the solid content of the acrylic copolymer, an ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L55E",
1.0 part by weight (solid content: 55% by weight) was uniformly mixed to prepare a solution of the acrylic pressure-sensitive adhesive composition. Further, the oxidation index and the softening point index of each acrylic pressure-sensitive adhesive composition were obtained by the above formulas (1) and (2). The results are shown in Table 2.

[0044]

[Table 2]

(Examples 1 to 5 and Comparative Examples 1 to 6) Solutions of the above acrylic pressure-sensitive adhesive compositions were treated on one surface with a release-treated surface of a polyethylene terephthalate (PET) film having a thickness of 38 μm. And was dried at a temperature of 110 ° C. for 5 minutes to form a pressure-sensitive adhesive layer having a thickness of 65 μm. Then, the above-mentioned pressure-sensitive adhesive layer was laminated on both sides of a cellulosic non-woven fabric having a basis weight of 14 g / m ² , pressure-bonded and transferred to both sides, and then 40
It was aged at ℃ for 3 days to prepare a double-sided adhesive tape having a thickness of 140 μm. Next, a PET film having a thickness of 38 μm was lined on one surface of each of the above double-sided adhesive tapes, and an adhesive tape having an adhesive layer on only one surface was produced and evaluated.

The following stainless steel plates and vinyl chloride resin plates were used as test pieces. Stainless steel plate As a stainless steel plate, "SUS # 30" with a thickness of 2 mm
4 ”(manufactured by Nippon Test Panel Co., Ltd.) was used. Vinyl chloride resin plate As a vinyl chloride resin plate, vinyl chloride resin (degree of polymerization 1
100) 100 parts by weight, dioctyl phthalate 50 parts by weight, organotin stabilizer (manufactured by Koseisha, trade name "T-1000"
BHJ ") 2 parts by weight and 15 parts by weight of calcium carbonate, and a vinyl chloride resin plate having a thickness of 5 mm was used.

An adhesive tape lined with the PET film was attached to the stainless steel plate and vinyl chloride resin plate for 2 k.
It is attached by reciprocating twice with a pressure roller of 300 g at a speed of 300 mm / min, and cured by leaving it in a thermostatic chamber at 23 ° C. for 24 hours. Then, it is adhered to an initial 180 ° peel adhesive force of 80 in accordance with JIS Z0237. The ° C shear retention was measured. In addition, the backed adhesive tape,
300 kg on the vinyl chloride resin plate with a 2 kg pressure roller
Attach by reciprocating 2 times at a speed of mm / min,
After curing by allowing it to stand in a thermostatic chamber at 80 ° C. for 1 week, the 180 ° peel adhesive strength and the 80 ° C. shear holding power over time were measured according to JIS Z0237. The measurement results are shown in Table 3.

[0048]

[Table 3]

(Examples 6 to 10 and Comparative Examples 7 to 12) Solutions of the above acrylic pressure-sensitive adhesive compositions were applied onto the release-treated surface of a PET film having a thickness of 38 μm and subjected to release treatment on one side. It was dried at a temperature of 110 ° C. for 5 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 μm. As a vinyl chloride resin sheet, 100 parts by weight of vinyl chloride resin, 30 parts by weight of dioctyl phthalate, an organic tin stabilizer (manufactured by Koseisha, trade name "T-100"
0BHJ ") 7 parts by weight and calcium carbonate 20 parts by weight,
Organic solvent (Mitsubishi Chemical Co., trade name "Solvesso") 60
A vinyl chloride resin organosol consisting of parts by weight was applied onto a process paper and heat-cured to obtain a thickness of 50 μm. After transferring the pressure-sensitive adhesive layer on one surface of the vinyl chloride resin sheet, it was cured at 40 ° C. for 3 days to prepare a vinyl chloride resin sheet-based pressure-sensitive adhesive tape.

The above-mentioned adhesive tape of vinyl chloride resin sheet base material was applied to the above stainless steel plate with a 2 kg pressure roller.
It was attached by reciprocating 2 times at a speed of 00 mm / min, and allowed to stand for 24 hours in a thermostatic chamber at 23 ° C., and then cured for 180 hours according to JIS Z0237.
Peel adhesion and 80 ° C. shear retention were measured. Also,
After the same operation, the sample was left to stand in a thermostatic chamber at 80 ° C. for 1 week for curing, and then the 180 ° peel adhesive force and the 80 ° C. shear retention force were measured in accordance with JIS Z0237. Table 4 shows the measurement results.

[0051]

[Table 4]

(Examples 11 to 15, Comparative Examples 13 to 18)
The solution of each of the above-mentioned acrylic pressure-sensitive adhesive compositions was applied onto the release-treated surface of a PET film having a thickness of 38 μm and subjected to release treatment on one side, dried at a temperature of 110 ° C. for 5 minutes, and had a thickness of 25 μm.
m of the pressure-sensitive adhesive layer was formed. Then, the above-mentioned pressure-sensitive adhesive layer was transferred onto the aluminum vapor-deposited surface of an aluminum vapor-deposited PET film (trade name “ZAGVM film” manufactured by Saichi Industry Co., Ltd.), and then cured at 40 ° C. for 3 days to perform aluminum vapor deposition P.
An ET film-based adhesive tape was produced.

Each of the above aluminum vapor-deposited PET film-based adhesive tapes was attached to the above-mentioned stainless steel plate by reciprocating two times at a speed of 300 mm / min with a pressure roller of 2 kg and left in a constant temperature room at 23 ° C. for 24 hours. After curing, the initial 180 ° peel adhesive force and 80 ° C. shear holding force were measured according to JIS Z0237. In addition, after the same operation, the sample was left to stand in a thermostatic chamber at 80 ° C. for 1 week for curing, and then the 180 ° peel adhesive force and the 80 ° C. shear holding force were measured in accordance with JIS Z0237.

Further, the above-mentioned pressure-sensitive adhesive tape of an aluminum vapor-deposited PET film substrate was attached to a galvanized steel sheet at 23 ° C., left for 2 hours, and then immersed in a 5% by weight sodium chloride aqueous solution at 30 ° C. for 4 hours. , Measure the maximum length in which salt water has penetrated from the end of the adhesive layer in mm units,
The salt water resistance was measured. The above measurement results are shown in Table 5.

[0055]

[Table 5]

[0056]

Since the acrylic pressure-sensitive adhesive composition of the invention of claim 1 is constructed as described above, it contains a stainless steel plate, a plasticizer and a metal stabilizer when used as an adhesive tape. It has excellent initial adhesiveness to adherends such as vinyl chloride resin plates. Furthermore, after being attached to the vinyl chloride resin, there is no decrease in the adhesive strength due to the transfer of the plasticizer or the metal-based stabilizer to the adhesive layer even after heating and aging, and it shows good adhesive performance over time. ing.

The pressure-sensitive adhesive tape according to the second aspect of the present invention is constructed as described above, so that it is excellent in the initial pressure-sensitive adhesive performance and also has a pressure-sensitive adhesive layer of a plasticizer or a metal-based stabilizer even after being aged with heating. There is no decrease in the adhesive strength due to the transition to, and good adhesive performance over time is exhibited.

Since the pressure-sensitive adhesive tape of the invention of claim 3 is constructed as described above, it is excellent in the initial pressure-sensitive adhesive performance and, when it is used for the purpose of being attached to the bulk of a fluorescent lamp or the like to enhance the reflection efficiency. The ionization of the metal thin film layer due to moisture or water in the air, and the decrease in the adhesive strength due to the migration of the metal ions to the adhesive layer, the adhesive tape does not peel from the end. ing.

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Claims (3)

[Claims] 1. An alkyl (meth) acrylate as a main component, having a weight average molecular weight (Mw) of 200,000 to 1,500,000, and a ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn). An acrylic pressure-sensitive adhesive composition comprising an acrylic copolymer having 2 to 4 and a tackifying resin, wherein the acid value index (AP) = Σ (AVi × Wi) below (1) The acid value index represented by [AVi: acid value of tackifier resin of i-th component, Wi: weight fraction of tackifier resin of i-th component in acrylic pressure-sensitive adhesive composition] is 2 to 25 And softening point index (SpP) = Σ (Wi / Spi) × 10000 (2) [Spi: softening point (° K) of the tackifying resin of the i-th component,
Wi: weight fraction of tackifying resin as the i-th component in the acrylic pressure-sensitive adhesive composition], and the softening point index is 4.5 to 6.
5. The acrylic pressure-sensitive adhesive composition, which is 5. 2. A pressure-sensitive adhesive layer comprising the acrylic pressure-sensitive adhesive composition according to claim 1 provided on at least one surface of a flexible film comprising a vinyl chloride resin, a plasticizer and a metal-based stabilizer. And adhesive tape. 3. A pressure-sensitive adhesive tape comprising a plastic film, a metal thin film and a pressure-sensitive adhesive layer comprising the acrylic pressure-sensitive adhesive composition according to claim 1, which are sequentially provided on one surface of the plastic film.