JPH08109356A - Acrylic tacky tape - Google Patents

Abstract

PURPOSE: To obtain an acrylic tacky tape excellent in bonding performances such as initial adhesive strength, peel strength or shearing force not only in the original state but also at high temperatures by forming a specific acrylic tacky agent layer on a specified acrylic tacky sheet. CONSTITUTION: This product is obtained by forming (B) a tacky agent layer comprising an acrylic copolymer, containing >=70wt.% gel component and having 500000-1500000 weight-average molecular weight on at least one surface of (A) an acrylic tacky sheet comprising an acrylic copolymer containing a particulate filler, having 1-150μm average particle diameter and dispersed therein. The component (A) is preferably obtained by a method for including the particulate filler such as fine polyethylene particles in a photopolymerizable composition comprising 100 pts.wt. photopolymerizable monomers comprising 50-98wt.% alkyl (meth)acrylate having a 1-12C alkyl group and 50-2wt.% vinyl monomer containing a polar group, 0.01-1 pt.wt. monomer having >=2 reactive double bonds and 0.01-5 pts.wt. photopolymerization initiator and photopolymerizing the resultant photopolymerizable composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic pressure-sensitive adhesive sheet obtained by photopolymerization, and more specifically, an acrylic pressure-sensitive adhesive sheet having excellent adhesive strength and capable of easily performing a work for joining structures and the like. Regarding adhesive tape.

[0002]

2. Description of the Related Art Conventionally, a polyethylene foam, a chloroprene foam, a urethane foam, an acrylic foam or the like is used as a base material, and an acrylic pressure-sensitive adhesive layer is provided on both sides of the base material. Double-sided foam adhesive tape is adhesive-free in many fields such as automobile industry, electrical and electronic industry, building materials, etc. from the viewpoint of solvent-free work safety and high work efficiency such as speed of adhesive force development. Is used for joining work instead.

A novel adhesive tape, which is suitable for the above-mentioned use, is obtained by dispersing glass microbubbles (hollow body fine particles) in an adhesive layer to satisfy both performances of peeling force and shearing force under normal conditions. It has been done
7-17030). Further, in the above-mentioned documents,
For the purpose of improving the initial adhesive strength, a non-filler type acrylic pressure-sensitive adhesive is laminated on one surface of the above-mentioned pressure-sensitive adhesive tape as a surface layer paste.

[0004]

However, in the ordinary acrylic pressure-sensitive adhesives described in the above-mentioned documents, when the acrylic polymer has a low molecular weight, the peeling force and the shearing force in the normal state are excellent, but at the high temperature the surface layer Due to the decrease in the adhesive strength of the adhesive, the adhesive performance such as peeling force and shearing force at high temperature was not yet sufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an acrylic pressure-sensitive adhesive sheet having excellent adhesive performance such as peeling force and shearing force not only under normal conditions but also under high temperature. That is.

[0006]

In the acrylic pressure-sensitive adhesive tape of the present invention, an acrylic pressure-sensitive adhesive sheet is used as a substrate, and a pressure-sensitive adhesive layer made of an acrylic copolymer is formed on at least one surface of the acrylic pressure-sensitive adhesive sheet. Has been done.

The above-mentioned acrylic pressure-sensitive adhesive sheet imparts a peeling force and a shearing force to the pressure-sensitive adhesive tape, and is made of an acrylic copolymer (A) in which a granular filler is dispersed.

The above acrylic copolymer (A) is obtained by a solution polymerization method of polymerizing in a solvent, an emulsion polymerization method of polymerizing in water, a photopolymerization method of polymerizing by irradiating with light (mainly ultraviolet rays), and the like. However, the photopolymerization method is particularly preferable in that the thickness can be secured, the polymerization rate is high and the production efficiency is high, and the granular filler is easily dispersed in the acrylic copolymer (A). preferable.

The acrylic copolymer obtained by the above photopolymerization method includes 100 parts by weight of a photopolymerizable monomer composed of (meth) alkyl acrylate (a) and a vinyl monomer (b) having a polar group, and a reactive double polymer. It is preferably formed from a photopolymerizable composition comprising 0.01 to 1 part by weight of a monomer (c) having two or more bonds and 0.01 to 5 parts by weight of a photopolymerization initiator (d).

The above (meth) alkyl acrylate (a)
Is preferably an alkyl group having 1 to 12 carbon atoms,
More preferably, it is 4-12, for example, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-.
Examples thereof include octyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate, and these can be used in combination of two or more.

The above-mentioned (meth) alkyl acrylate is preferably contained in an amount of 50 to 98% by weight based on the total amount of the photopolymerizable monomer because the shearing force of the pressure-sensitive adhesive sheet obtained is decreased when the amount is increased and the peeling force is decreased when the amount is decreased. And more preferably 70 to 95% by weight.

Vinyl monomer (b) having the above polar group
Is a monomer copolymerizable with the (meth) alkyl acrylate (a), and specifically, a vinyl monomer having a carboxyl group such as (meth) acrylic acid, maleic acid, fumaric acid or itaconic acid, or an anhydride thereof. Substance, (meth) acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropylacrylamide, etc. , 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl acrylate, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, caprolactone-modified (meth) acrylate. Vinyl monomers having a hydroxyl group.

When the vinyl monomer having a polar group is increased, the peeling force of the obtained pressure-sensitive adhesive sheet is lowered, and when it is decreased, the shearing force is lowered. Therefore, it is preferably 2 to 50% by weight based on the total amount of the photopolymerizable monomer. %, And more preferably 5 to 30% by weight.

The monomer (c) having two or more reactive double bonds used in the present invention is for crosslinking the copolymers, specifically, hexanediol (meth) acrylate, ( Poly) ethylene glycol diol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylpropane tri Examples thereof include methacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate and urethane acrylate.

If the amount of the above-mentioned monomer added is too large, the crosslink density becomes too high, and it becomes difficult to obtain the peeling force. If it is too small, the crosslink density becomes too low and it becomes difficult to obtain the cohesive force. It is preferably 0.01 to 1 part by weight, and more preferably 0.02 to 0.8 part by weight, based on 100 parts by weight of the total amount.

Examples of the photopolymerization initiator (d) used in the present invention include ketone-based compounds such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone [Darocur 2959: manufactured by Ciba Geigy]. , Α-
Hydroxy-α, α'-dimethyl-acetophenone [Darocur 1173: manufactured by Ciba Geigy], methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone [Irgacure 651: manufactured by Ciba Geigy],
Examples thereof include acetophenone-based compounds such as 2-hydroxy-2-cyclohexylacetophenone [Irgacure 184: manufactured by Ciba-Geigy], ketal-based compounds such as benzyldimethyl ketal, halogenated ketones, acylphosphinoxides, and acylphosphonates.

If the amount of the above-mentioned photoinitiator added is too large, the amount of radicals generated becomes too large, and a low-molecular weight copolymer is likely to be produced. If it is too small, the polymerization reaction is difficult to proceed. The amount is preferably 0.1 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight.

The granular filler used in the above-mentioned acrylic pressure-sensitive adhesive sheet imparts high shearability and peel strength to the pressure-sensitive adhesive sheet obtained, and is, for example, a glass balloon,
Inorganic hollow particles such as alumina balloons, shirasu balloons and fly ash balloons, polymethylmethacrylate (PMMA), acrylonitrile-vinylidene chloride copolymer, polystyrene, organic hollow particles such as phenol resin, glass beads, silica beads, silica alumina Examples thereof include beads, fly ash, inorganic particles such as synthetic mica, organic particles such as polyethyl acrylate, polyethylene, polyurethane and polypropylene, and porous filler such as diatomaceous earth and porous silica.

The above-mentioned granular filler has an average particle diameter of 1 to 150 μm, because the shear strength of the obtained pressure-sensitive adhesive sheet becomes insufficient when the average particle diameter becomes large, and it becomes difficult to obtain sufficient peel strength when the average particle diameter becomes small.

A tackifying resin may be added to the photopolymerizable composition of the present invention, for example, rosin resin, modified rosin resin, terpene resin, terpene phenol resin, C5 and C9 petroleum resin, The coumarone resin and these hydrogenated products can be used alone or in combination.

When the photopolymerizable composition is polymerized,
Since the polymerization rate may decrease or the molecular weight may decrease, in such a case, for example, a chain transfer agent such as n-dodecyl mercaptan (dodecane thiol) or t-dodecyl mercaptan is used as a photopolymerizable monomer. It may be added within the range of 0.01 to 0.1 parts by weight with respect to 100 parts by weight.

As the method for producing the pressure-sensitive adhesive sheet of the present invention, the above-mentioned photopolymerizable composition is applied onto a release sheet using a coating machine such as a roll coater and irradiated with light to polymerize on the release sheet. There is a method.

In the above method, in order to prevent the granular filler in the photopolymerizable composition from settling and becoming non-uniform, the photopolymerizable composition is sufficiently stirred and then thickened. Further, thixotropy is imparted in order to secure a coating thickness on the release sheet so as to have a predetermined thickness. Then, the pressure-sensitive adhesive sheet is obtained by irradiating the coated surface of the photopolymerizable composition with light.

The thickness of the pressure-sensitive adhesive sheet of the present invention is preferably in the range of 50 μm to 5 mm from the viewpoint of ease of use, and 100
When the thickness is less than or equal to μm, the coating can be performed even when the viscosity is 1000 cps and the thixotropic index value (hereinafter, TI value) is about 1.5, but when manufacturing a sheet having a thickness larger than that, a higher viscosity or A higher TI value is preferable from the viewpoint of ensuring the thickness.

As means for increasing the viscosity of the photopolymerizable composition, acrylic rubber, nitrile rubber, diblock such as styrene-isoprene-styrene block (SIS), or elastomer such as triblock rubber, polymethylmethacrylate ( PMMA), polystyrene (P
Examples of the method include adding and dissolving a thermoplastic resin such as st).

The viscosity can also be increased by preliminarily partially polymerizing a part of the photopolymerizable composition without adding the above-mentioned additives. In this case, a monomer having two or more reactive double bonds is used. It is preferable to carry out before the addition of so as to prevent the generation of microgel, because streaks, spots and the like are less likely to occur during coating.

As means for increasing the photopolymerizable composition to a high TI value, silica particles having an average particle diameter of 5 μm or less, alumina particles, white carbon such as silica-alumina particles,
A method of adding a thixotropy-imparting agent such as carbon black can be mentioned.

For light irradiation, lamps having an emission distribution at a light wavelength of 400 nm or less are used. Examples of such lamps are a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp and a black light. Examples include lamps, microwave-excited mercury lamps, and metal halide lamps. Among them, the chemical lamp is preferable for producing a thick film sheet because it efficiently emits light in the active region of the photoinitiator, and the light irradiation intensity is 0.
The range of 1 to 100 mW / cm ² is preferable.

The photopolymerization reaction in the present invention is inhibited by oxygen in the air and oxygen dissolved in the photopolymerizable composition. For this reason, it is preferable to use a method that does not interfere with oxygen for the light irradiation.

As the above-mentioned method, for example, the coated photopolymerizable composition is covered with a film such as polyethylene terephthalate (PET) or Teflon whose surface is release-treated,
Examples include a method of irradiating the composition with light through this film, and a method of reacting in an inert zone in which oxygen is replaced with an inert gas such as nitrogen gas or carbon dioxide gas. In the method of reacting in the inert zone, the oxygen concentration in the light irradiation atmosphere is preferably 5000 ppm or less from the viewpoint of smoothly performing photopolymerization,
More preferably, it is 300 ppm or less.

The acrylic pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer made of the acrylic copolymer (B) formed on at least one surface of the acrylic pressure-sensitive adhesive sheet.

The acrylic copolymer (B) forming the pressure-sensitive adhesive layer contains an alkyl (meth) acrylate as a main component and was used to obtain the acrylic copolymer in the acrylic pressure-sensitive adhesive sheet shown above. , And those similar to alkyl (meth) acrylates.

When the content of the above-mentioned alkyl (meth) acrylate in the acrylic copolymer is low, the cohesive force becomes too high and the initial adhesiveness is lowered, and when the content is high, the cohesive force is low and the shearing force is lowered. Therefore, it is preferably 40 to 95% by weight, and more preferably 60 to 95% by weight.
It is 93% by weight.

In addition, a vinyl monomer having a polar group copolymerizable with the above-mentioned alkyl (meth) acrylate may be copolymerized, and in order to obtain the acrylic copolymer in the acrylic pressure-sensitive adhesive sheet shown above as well. The same thing as what was used is mentioned.

When the content of the vinyl monomer having a polar group in the acrylic copolymer is low, the cohesive force is small and the shearing force is low, and when it is high, the cohesive force is too high and the initial adhesiveness is high. 5 to 2 because it decreases
0% by weight is preferred.

Further, as other copolymerizable vinyl monomers, vinyl acetate, vinyl propionate, styrene, isobornyl (meth) acrylate and the like can be mentioned. However, if the content of the above monomer is high, the cohesive force becomes too high. Therefore, the initial adhesiveness decreases, so that it is preferably 30% by weight or less.

If the weight average molecular weight of the acrylic copolymer is small, the cohesive force is small and the heat resistance is low.
On the other hand, if it is too high, the cohesive force will be too high and the initial adhesiveness will be deteriorated.

When the gel fraction of the acrylic copolymer is small, the cohesive force is small and the heat resistance is low. Therefore, it is preferable to have the gel component in an amount of 70% by weight or more.

The above acrylic component is immersed in the above gel component, a polar solvent (good solvent) such as ethyl acetate, toluene, tetrahydrofuran (THF), etc., and the insoluble matter (gel component) is filtered. It can be determined by measuring the weight fraction (% by weight) of the original copolymer weight.

As a method of obtaining the above gel component, in the case of solution polymerization and emulsion polymerization, toluylene diisocyanate (TDI), naphthylene-1,5-diisocyanate, diphenylmethane diisocyanate (MD
I), hexamethylene diisocyanate (HMDI),
Isophorone diisocyanate (IPDI), xylene diisocyanate (XDI), isocyanate crosslinking agents such as trimethylolpropane modified TDI, and epoxy crosslinking such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. And a method of crosslinking the copolymer obtained with an aziridine-based crosslinking agent such as N, N-hexamethylene-6,6-bis (1-aziridinecarboxamide).

Further, in the case of the photopolymerization method, a monomer having two or more copolymerizable unsaturated double bonds in the molecule may be used in place of the above-mentioned crosslinking agent to simultaneously crosslink from the polymerization stage. For example, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, Pentaerythritol tri (meta)
Examples thereof include acrylate, trimethylolpropane tri (meth) acrylate, (meth) allyl acrylate, (meth) vinyl acrylate, and divinylbenzene.

In the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the present invention, a tackifying resin may be added to the above acrylic copolymer, for example, rosin resin, modified rosin resin, terpene resin, terpene phenol resin. Resins, C5 and C9 petroleum resins, coumarone resins, and hydrogenated products thereof can be used alone or in combination.

When the 10-second shear creep compliance of the pressure-sensitive adhesive layer of the present invention is small, the pressure-sensitive adhesive layer becomes hard and the initial adhesive force is lowered, and when it is large, the pressure-sensitive adhesive layer becomes soft and the heat resistance is lowered to reduce the shear force. Since the balance of the peeling force decreases, it is preferably 2.0 to 3.2 × 10 ⁻⁶ cm ² /
It's Dyne.

The shear creep compliance is defined by the following equation as described in the above-mentioned document (Japanese Patent Publication No. 61-34760). J (t) = A
AXi / hF (where t is the time when the measurement is performed,
A is the area of one surface of the adhesive material, Xi is the position at time t (when it is less than h), and F is the weight acceleration of the mass connected to the wire connected to the intermediate plate. Is calculated by the force). A is cm ²
And h is cm and Xi is cm,
And when F is expressed by dyne, J (t) is cm ²
/ Given in dynes.

[0045]

In the present invention, a specific photopolymerizable composition is allowed to contain a granular filler as a filler and photopolymerized,
An acrylic pressure-sensitive adhesive sheet having high peeling force and shearing force can be obtained. Furthermore, by laminating a pressure-sensitive adhesive layer made of an acrylic copolymer, which is a non-filler type and has a specific high molecular weight and a high gel fraction, as the surface layer paste, the initial adhesive strength is high and the acrylic type adhesive is used even at high temperatures. It is possible to secure the high peeling force and shearing force that the adhesive sheet has.

[0046]

Embodiments of the present invention will be described below.
In the following, "parts" means "parts by weight". "Preparation of acrylic adhesive sheet" (Adhesive sheet 1) 2-ethylhexyl acrylate 85
0 parts, acrylic acid 50 parts, N-vinylpyrrolidone, 10
0 part, n-dodecanethiol 0.2 part, 2,2-dimethoxy-2-phenylacetophenone [trade name "Irgacure 651": manufactured by Ciba Geigy] 3 parts, and polyethylene fine particles [average particle diameter 20 [mu] m, trade name "Miperon XM-220 ": manufactured by Mitsui Petrochemical Co., Ltd.] 420 parts were placed in a separable flask and mixed by stirring until uniformly dispersed to obtain a photopolymerizable composition, and nitrogen gas was purged to remove dissolved oxygen. did.

Next, when the composition was irradiated with ultraviolet rays using a black lamp, the temperature of the composition increased and the viscosity increased at the same time. When the temperature of the composition increased by 5 ° C., the light irradiation was stopped (this composition is referred to as a partial photopolymerization thickening composition).

0.5 part of hexanediol diacrylate was added to the obtained partial photopolymerization thickening composition, and the thickness at the end of the polymerization was about 1 mm on a polyethylene terephthalate (PET) film which had been subjected to a peeling treatment. And then covered with the same PET film so as to be in contact with the coated surface.

Then, using a chemical lamp, the irradiation intensity of 2 mW / c was applied from above the PET film used for the cover.
Irradiation was performed at m ² for 8 minutes to obtain an acrylic pressure-sensitive adhesive sheet having a thickness of about 1 mm.

(Adhesive sheet 2) An acrylic adhesive sheet having a thickness of about 1 mm was obtained according to the same formulation and manufacturing method as in the adhesive sheet 1, except that the polyethylene fine particles were not added.

(Preparation of Acrylic Adhesives A to G) According to the composition of Table 1, 2-ethylhexyl acrylate,
n-Butyl acrylate, acrylic acid and n-dodecane thiol were charged in a separable flask together with 900 parts of ethyl acetate, the temperature was raised to reflux under a nitrogen gas atmosphere, the temperature was maintained for 20 minutes, and then benzyl peroxide 1.
A solution prepared by dissolving 0 part in 50 parts of ethyl acetate was dropped into the monomer component in the separable flask to carry out a polymerization reaction for 4 hours, and then the same amount of the benzyl peroxide solution was added dropwise to carry out a polymerization reaction for 3 hours. It was Then, add 500 parts of toluene and stir to mix to obtain a viscosity of 120.
0 cps of each adhesive solution was obtained. The weight average molecular weight of the acrylic copolymer in each adhesive solution was measured by gel permeation chromatography (GPC), and the results are shown in Table 1.

To 100 parts of the acrylic copolymer in each of the obtained pressure-sensitive adhesive solutions, an aziridine crosslinking agent [HD
U; N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) was added in the number shown in Table 1 to crosslink the acrylic copolymer to obtain an acrylic pressure-sensitive adhesive. The gel fraction of the acrylic pressure-sensitive adhesive was evaluated by the weight ratio (% by weight) of the original weight (each solid weight) to the insoluble matter after being immersed in ethyl acetate, and the results are also shown in Table 1. It was shown to.

[0053]

[Table 1]

(Preparation of acrylic pressure-sensitive adhesive tape) The acrylic pressure-sensitive adhesive obtained above was once applied to a release sheet and dried to form a pressure-sensitive adhesive layer having a thickness of 25 μm. Adhesive layers were formed on both sides of the sheet by a transfer method according to the combinations shown in Table 2.

[0055]

[Table 2]

(Measurement of Creep Compliance) The creep compliance was measured using the shear creep plastometer shown in FIG. The above acrylic pressure-sensitive adhesive was applied onto a smooth film of polytetrafluoroethylene and dried to prepare a sheet-like product 1a of the acrylic pressure-sensitive adhesive having a thickness of 500 μm. 2 sheets of the above-mentioned sheet 1a
It was cut into a shape of 0 mm × 20 mm, and sandwiched and fixed by the parallel plate 1b and the fixed parallel plate 1c.

Parallel plate 1b-Adhesive sheet 1a
-The stack of fixed parallel plates 1c is placed in an oven, 2
After stabilizing at 5 ± 0.5 ° C, a weight of 500g was connected to the parallel plate 1b via the pulley 1e by the wire 1d, and the wire recorder attached to the free end of the wire was started, and 10 seconds from the chart recorder. By reading the subsequent displacement (deviation length of the parallel plate 1b with respect to the fixed parallel plate 1c), the value of the 10-second shear creep compliance at a predetermined temperature can be calculated by the equation (J = AAXi / h).
Determined in F).

"Performance Evaluation of Adhesive Tape" (T-Type Peeling Test) As an adherend by the measuring method shown in FIG. 2, an aluminum alloy 110 described in JIS H4000.
What was cut into a size of 25 mm width x 100 mm using 0P was crimped to both sides of each cut piece (20 mm width x 100 mm) of each of the above-obtained adhesive tapes with a 2 kg roller to make two reciprocating crimps and 23 ° C. After being left in the atmosphere for 72 hours, a T-type peel test was performed at a pulling speed of 200 mm / min to measure the peel strength.

(Shear Test) As an adherend, SUS304
Using adhesive tape cut (20mm width x 100m
m), both sides are pressed back and forth with a 2 kg roller for 2
It was left for 3 days at 3 ° C. Then 2 for each
It was pulled in the shear direction at a pulling rate of 5 mm / min at a temperature of 3 ° C., and the shear strength was measured.

(Thermal softening test) As an adherend, SUS30
4 is used, and a cut piece of adhesive tape (20 mm x 20 m
m) was adhered and 100 μm of aluminum sea urchin was adhered as a backing, followed by two reciprocal pressure bonding with a 2 kg roller and left at 23 ° C. for 3 days. Then, a load of 1 kg was applied in the shearing direction of the adhesive tape, and the falling speed when the temperature was raised at a speed of 3 ° C./5 min was measured. Table 2 shows the creep compliance value and the performance evaluation result of the adhesive tape.

[0061]

The pressure-sensitive adhesive tape of the present invention is excellent in curved surface followability and extensibility in addition to the initial adhesive force, peeling force, and shearing force. Since it exhibits adhesive performance that can withstand various mechanical strengths, it is suitable for use as an adhesive tape for fixing various molded products such as automobile parts, building materials interior materials, exterior materials, electrical parts, signboards, displays, etc., and also used in a wide range of applications. I can.

[Brief description of drawings]

FIG. 1 is a schematic view of a shear creep plastometer for measuring creep compliance in Examples and Comparative Examples.

FIG. 2 is a side view showing a T-type peel test method for measuring peel strength in Examples and Comparative Examples.

[Explanation of symbols]

 1a Sheet of acrylic adhesive 1b Parallel plate 1c Fixed parallel plate 1d Wire 1e Pulley 2a Aluminum alloy 2b Cut piece of adhesive tape 2c Fixing stand 2d Hook

Claims (3)

[Claims] 1. A weight average molecular weight having 70% by weight or more of a gel component on at least one surface of an acrylic pressure-sensitive adhesive sheet made of an acrylic copolymer (A) in which a granular filler having an average particle size of 1 to 150 μm is dispersed. Fifty
An acrylic pressure-sensitive adhesive tape, wherein a pressure-sensitive adhesive layer made of up to 1.5 million acrylic copolymer (B) is formed. 2. The adhesive layer has a thickness of 2.0 to 3.2 × 10 ⁻⁶ cm.
The acrylic pressure-sensitive adhesive tape according to claim 1, which has a 10 second shear creep compliance of ² / dyne. 3. The acrylic copolymer (A) comprises 50 to 98% by weight of (a) a (meth) alkyl acrylate having an alkyl group having 1 to 12 carbon atoms and (b) a vinyl monomer having a polar group of 50 to 50% by weight. 2% by weight of photopolymerizable monomer 1
Formed from a photopolymerizable composition comprising 00 parts by weight, (c) 0.01 to 1 part by weight of a monomer having two or more reactive double bonds, and (d) 0.01 to 5 parts by weight of a photopolymerization initiator. The acrylic pressure-sensitive adhesive tape according to claim 1 or 2, wherein