JPH0570752A - Acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive tape, label or sheet - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive adhesive excellent in pressure-sensitive adhesiveness at high temperatures, low-temperature resistance and heat resistance by using a copolymer of n-butyl acrylate with another monomer and having a specified polydispersity index. CONSTITUTION:A pressure-sensitive adhesive composition mainly consisting of an acrylic copolymer containing 70-99.9wt.% at least one monomer of the formula (wherein R1 is H or methyl; and R2 is 2-18 C alkyl) and 0.1-30wt.% other monomers copolymerizable therewith and having a polydispersity index (Mw/Mn) (wherein Mw is the weight-average molecular weight of the acrylic copolymer, and Mn is the number-average molecular weight of the copolymer) is 4 or below. This composition can show a marked effect when its polydispersity is 4 or below. Therefore it can show both low-temperature resistance and heat resistance in respect that its heat resistance can be improved without heightening its glass transition point.

Description

Detailed Description of the Invention

[0001] The present invention relates to an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape, label or sheet which are particularly excellent in pressure-sensitive adhesive performance at high temperatures.

[0002]

2. Description of the Related Art Acrylic adhesives have excellent adhesive properties such as adhesive strength and cohesive strength, weather resistance, oil resistance, etc., and are therefore used as adhesives for forming adhesive layers for adhesive tapes, labels or sheets. Widely used.

Conventionally, as an acrylic pressure-sensitive adhesive, (meth) acrylic acid alkyl ester capable of forming an adhesive polymer having a relatively low glass transition point such as n-butyl acrylate and 2-ethylhexyl acrylate is used as a main component, In addition to this, monomers having functional groups such as acrylic acid, 2-hydroxyethyl (meth) acrylate, and acrylamide, and polymers having a relatively high glass transition point are used as components for increasing the crosslinking point and the intermolecular force and improving the cohesive force. As a hard monomer component capable of forming styrene, a copolymer obtained by copolymerizing styrene, vinyl acetate, etc. is used.

For example, in a solvent-type acrylic pressure-sensitive adhesive, the polymer therein is generally one having a weight average molecular weight of 200,000 to 1,000,000 [polystyrene conversion of gel permeation chromatography (GPC method St conversion)]. However, since it is generally produced by radical polymerization, it is a collection of thousands to millions of molecules, and the polydispersity index (Mw / Mw /
Those having a Mn) of about 5 or more are used.

[0005]

In the conventional acrylic pressure-sensitive adhesives as described above, the elastic modulus decreases with an increase in temperature,
The higher the temperature, the more the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, such as the pressure-sensitive adhesive tape, flows out from the side of the base material and peels off the pressure-sensitive adhesive tape.

However, if the glass transition point of the polymer is further increased in order to obtain heat resistance, the cold resistance and the tackiness will be deteriorated. Therefore, it is designed in a well-balanced manner. However, it does not solve the above problems.

The present invention solves the above-mentioned conventional problems, and not only the adhesive performance at room temperature but also the acrylic adhesive composition excellent in both cold resistance and heat resistance, adhesive tape, and label. Alternatively, the purpose is to provide a sheet.

[0008]

The invention of claim 1 of the present application is based on the general formula

[0009]

[Chemical 2]

(Wherein R ₁ is hydrogen or a methyl group, R ₂
Is 70 to 99.9% by weight of at least one monomer represented by an alkyl group having 2 to 18 carbon atoms) and 0.1 to 30% by weight of another monomer copolymerizable with these monomers. The ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic copolymer containing the acrylic copolymer as the main component as the main component, that is, polydispersity (Mw / M)
It is an acrylic adhesive composition in which n) is 4 or less.

The invention of claim 2 of the present application is an adhesive tape, label or sheet using the acrylic adhesive composition of claim 1. The monomer component constituting the acrylic copolymer used in the present invention includes (a) the general formula

[0012]

[Chemical 3]

(Wherein R ₁ is hydrogen or a methyl group, R _{2 is}
Is an alkyl group having 2 to 18 carbon atoms) 1
It is composed of one or more kinds of monomers and another monomer copolymerizable with the monomers (b) and (a).

Examples of the monomer (a) include n-
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and other monomers capable of forming an adhesive polymer are preferably used, and ethyl (meth) acrylate and methyl (meth) acrylate are preferably used. ) A monomer capable of forming a polymer for controlling the glass transition point such as acrylate is also used as necessary.

Examples of the monomer (b) include monomers capable of reacting with a cross-linking agent to form a polymer capable of improving cohesive force, such as (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate and acrylamide. It is preferably used to form a monomer having a high glass transition point such as vinyl acetate, styrene, N-vinylpyrrolidone, or a polymer having a low glass transition point such as tetrahydrofurfuryl acrylate or polyethylene glycol acrylate. The resulting monomer can be used.

The copolymer composed of the above-mentioned monomer components (a) and (b) is prepared by solution polymerization or bulk polymerization using a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile. It can be produced by emulsion polymerization using a water-soluble initiator such as ammonium persulfate or potassium persulfate.

The content ratio of each component in the above-mentioned copolymer composed of the monomer components (a) and (b) is 70 to 99.9% by weight of the monomer component (a), and (b). It is necessary that the monomer component is 0.1 to 30% by weight.

When the monomer component (b) in the copolymer is less than 0.1% by weight and the monomer (a) exceeds 99.9% by weight, the copolymer is reacted with a crosslinking agent. Therefore, the effect of improving the cohesive force cannot be expected, and conversely, when the amount of the monomer (b) exceeds 30% by weight and the amount of the monomer (a) is less than 70% by weight, the adhesive performance is deteriorated. Will end up.

The weight average molecular weight (Mw) of the obtained acrylic copolymer is preferably 50 × 10 ⁴ or more, more preferably 60 × 10 ⁴ or more. When the weight average molecular weight (Mw) of the copolymer is less than 50 × 10 ⁴ , the adhesive performance tends to decrease.

The glass transition point of the acrylic copolymer is preferably -25 ° C or higher. When the glass transition point is lower than -25 ° C, cohesiveness and heat resistance tend to be lowered.

The glass transition temperature (Tg) is determined by measuring the dynamic viscoelastic behavior of the polymer at a frequency of 10 Hz using a viscoelastic spectrometer and calculating the ratio (tan δ) between the storage elastic modulus and the loss elastic modulus. It was measured by the method shown by the temperature showing the peak of a certain loss tangent curve.

The acrylic pressure-sensitive adhesive is reacted (crosslinked) with an organic compound or organometallic compound having a polyfunctional group as a cross-linking agent at the time of use in order to improve cohesive force, heat resistance, solvent resistance and the like. As such a cross-linking agent,
For example, polyisocyanate, epoxy resin, melamine resin, aziridine compound, polyvalent metal salt, metal chelate and the like are used.

The amount of addition is 100% of the acrylic copolymer.
0.001 to 5 parts by weight is preferable with respect to parts by weight. If the addition amount is less than 0.001, it is difficult to crosslink the copolymer to improve the cohesive force, and conversely, if it exceeds 5 parts by weight, the adhesive performance tends to decrease.

Further, a tackifying resin is added for the purpose of improving the adhesive force to a non-polar substance. Examples of such resins include rosin-based resins, xylene-based resins, phenol-based resins, C9 petroleum-based resins, C5 / C9 copolymerized petroleum-based resins, coumarone-indene-based resins, terpene-based resins, and the like. A modified resin or the like is used. further,
A softening point of around 60 to 180 ° C. is used centering on a softening point of around 100 ° C.

The amount of addition is 100% of the acrylic copolymer.
The amount is preferably 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, based on parts by weight. If the amount is less than 1 part by weight, the adhesive performance to non-polar substances tends to decrease, and conversely, if the amount exceeds 50 parts by weight, the heat resistance tends to deteriorate.

In addition to the above, the acrylic pressure-sensitive adhesive composition of the present invention may contain a filler such as calcium carbonate or titanium oxide as a filler or a filler which is usually used. This acrylic pressure-sensitive adhesive composition, for example, in a state of being dissolved or dispersed in a solvent or water, is applied to a substrate such as paper, woven cloth, nonwoven cloth, cellophane, various plastic films, foamed sheets, metal foils, etc. Is dried by heating to produce an adhesive tape, label or sheet having an adhesive layer formed on a substrate.

[0027]

The acrylic pressure-sensitive adhesive composition of the present invention has a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer, that is, the polydispersity (Mw / Mn) is 4 or less. Therefore, it is possible to suppress the decrease in the storage elastic modulus and the loss elastic modulus at a high temperature, and both can be maintained at a high level. That is, it prevents the flow of adhesive at high temperatures,
Furthermore, it means improved heat resistance that makes it difficult to peel off,
In particular, when the polydispersity (Mw / Mn) is 4 or less, the effect becomes remarkable. Therefore, it is a high-performance pressure-sensitive adhesive composition that can achieve both cold resistance and heat resistance in that the heat resistance can be improved without raising the glass transition point of the pressure-sensitive adhesive.

When an appropriate amount of an organic compound or organometallic compound having a functional group as a crosslinking agent is added to the pressure-sensitive adhesive composition, the copolymer is appropriately crosslinked, and the cohesive strength and heat resistance are excellent. It becomes a thing.

Further, when an appropriate amount of tackifying resin is added, the adhesiveness to non-polar substances becomes excellent.
The pressure-sensitive adhesive tape, label or sheet according to the invention of claim 1 of the present application is a high-performance one having both cold resistance and heat resistance performance by using the acrylic pressure-sensitive adhesive composition.

[0030]

EXAMPLES Examples of the present invention will be described below. Example 1 (1) Polymerization of Acrylic Copolymer 95 parts by weight of n-butyl acrylate, 5 parts by weight of acrylic acid, and lauryl mercaptan 0.0 as a chain transfer agent.
2 parts by weight and 80 parts by weight of ethyl acetate as a solvent were charged into a five-necked flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet so that the total amount was 1 kg, and the mixture was stirred and dissolved. Purge with nitrogen gas for about 30 minutes to remove oxygen dissolved in the monomer solution.

Then, the air in the flask was replaced with nitrogen gas, the temperature was raised with stirring, and the temperature was maintained at 70 ° C. to dissolve 0.05 part by weight of benzoyl peroxide as a thermal polymerization initiator in 3 cc of ethyl acetate. Then, the mixture is dropped with a dropping funnel. The reaction started, and the reaction was carried out at the same temperature for 10 hours to obtain an acrylic copolymer solution.

(2) Measurement of molecular weight of acrylic copolymer The weight average molecular weight (Mw) and number average molecular weight (Mn) of the acrylic copolymer were measured by GPC method St conversion. The results are shown in Table 1.

The method of measuring the molecular weight by the GPC method St conversion is as follows. By gel permeation chromatography, standard polystyrene was used as a reference, tetrahydrofuran was used as an eluent, and detection was performed using a refractometer.

(3) Production of Acrylic Adhesive Tape With respect to 100 parts by weight of the solid content of the above acrylic copolymer solution, N, N'-hexamethylene-1,1 as a crosslinking agent,
Add 0.14 parts by weight of 6-bis (1-aziridinecarboxamide) (manufactured by Mutual Pharmaceutical Co., Ltd .: trade name "HDU"),
The obtained solution was applied onto a polyethylene terephthalate (PET) film having a thickness of 38 μm so that the thickness after drying was 25 μm, and then dried at 110 ° C. for 3 minutes to produce an acrylic pressure-sensitive adhesive tape.

(4) Measurement of Physical Properties A test piece was prepared from this acrylic pressure-sensitive adhesive tape and subjected to the following physical property tests. The results are shown in Table 1.

Storage Elasticity A viscoelasticity spectrometer (manufactured by Iwamoto Seisakusho Co., Ltd.) was used to measure the storage elastic modulus.

Loss Elastic Modulus A viscoelasticity spectrometer (manufactured by Iwamoto Seisakusho) was used to measure the shear load.

90 ° Peeling Retention (80 ° C.) At normal temperature, a tape was attached to a SUS304 plate with a width of 20 mm, left at 80 ° C. for 20 minutes, and then a load of 100 g was applied to peel the tape in a 90 ° direction. The peeling distance per unit time was measured.

90 ° Peeling Retention Force (160 ° C.) The measurement method is the same as 90 ° Peeling retention force (80 ° C.) except that the measurement temperature is 160 ° C.

SP Adhesiveness According to JIS Z0237, a tape was attached to a SUS304 plate with a width of 20 mm, and the 180 ° peel strength was measured after standing at 23 ° C. for 20 minutes. Pulling speed is 300mm /
It was set to min.

Low-speed peeling force The same as the measuring method of SP adhesive force except that the pulling speed was set to 2 mm / min.

Ball Tack J. The measurement is performed according to the Dow method (20 ° C.), and the measurement is performed at x / 32 inch. Example 2 Except that 97 parts by weight of n-butyl acrylate, 3 parts by weight of acrylic acid, and 0.05 part by weight of lauryl mercaptan as a chain transfer agent were used as the compounding composition of Example 2 .
In the same manner as in Example 1, an acrylic copolymer was obtained, the molecular weight was measured, an acrylic pressure-sensitive adhesive tape was produced, and the physical properties were measured. The results are shown in Table 1.

Example 3 As a compounding composition, 77 parts by weight of n-butyl acrylate, 20 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and lauryl mercaptan as a chain transfer agent of 0.
After obtaining an acrylic copolymer and measuring the molecular weight in the same manner as in Example 1 except that 03 parts by weight was used,
An acrylic pressure-sensitive adhesive tape was manufactured and its physical properties were measured. The results are shown in Table 1.

Comparative Example 1 As a compounding composition, 95 parts by weight of n-butyl acrylate, 5 parts by weight of acrylic acid and 1 part of ethyl acetate as a solvent were used without using lauryl mercaptan as a chain transfer agent.
A total of 1 kg of 100 parts by weight was charged into a five-necked flask, and the reaction was started at 70 ° C. in the same manner as in Example 1. After the reaction at this temperature for 3 hours, the temperature of the reaction system is changed to the boiling point (about 85
C.) and reacted for 7 hours under reflux to obtain an acrylic copolymer. After measuring the molecular weight of this acrylic copolymer, an acrylic pressure-sensitive adhesive tape was produced and its physical properties were measured. The results are shown in Table 1.

Comparative Example 2 As a compounding composition, without using lauryl mercaptan as a chain transfer agent, 97 parts by weight of n-butyl acrylate, 3 parts by weight of acrylic acid, and 1 part of ethyl acetate as a solvent.
An acrylic resin-based copolymer solution was obtained in the same manner as in Comparative Example 1 except that 50 parts by weight was charged into a five-necked flask in total of 1 kg. After measuring the molecular weight of this acrylic copolymer, an acrylic pressure-sensitive adhesive tape was produced and its physical properties were measured. The results are shown in Table 1.

Comparative Example 3 As a compounding composition, without using lauryl mercaptan as a chain transfer agent, 77 parts by weight of n-butyl acrylate, 20 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and ethyl acetate as a solvent were used. Comparative Example 1 except that 120 parts by weight and a total of 1 kg were charged in a five-necked flask.
An acrylic resin copolymer was obtained in the same manner as in. After measuring the molecular weight of this acrylic copolymer, an acrylic pressure-sensitive adhesive tape was produced and its physical properties were measured. The results are shown in Table 1.

[0047]

[Table 1]

As is clear from Table 1, in each of the examples of the present invention, both the storage elastic modulus and the loss elastic modulus at high temperature can be suppressed to a high level, and the peeling at high temperature can be achieved. Excellent holding power and low-speed peeling power. On the other hand, in each of the comparative examples, the adhesive performance at high temperature is inferior. Example 4 An acrylic copolymer solution was obtained and the molecular weight of the acrylic copolymer was measured in the same manner as in Example 1, and then crosslinked with 100 parts by weight of the solid content of the acrylic copolymer solution. Additive of 1 mol of trimethylolpropane and 3 mol of tolylene diisocyanate as an agent (manufactured by Nippon Polyurethane Company:
Example 1 except that 0.8 parts by weight of the product name "Coronate L") and 20 parts by weight of a special rosin ester (manufactured by Arakawa Chemical Co., Ltd .: product name "Super Ester A-115") as a tackifying resin were added. In the same manner as above, an acrylic pressure-sensitive adhesive tape was produced, and its physical properties were measured. The results are shown in Table 2. The 90 ° peel holding force (120 ° C) was the same as the 90 ° peel holding force (80 ° C) except that the measurement temperature was 120 ° C.
(° C) was measured by the same measurement method.

Example 5 The same as Example 1 except that 93 parts by weight of n-butyl acrylate, 7 parts by weight of acrylic acid, and 0.02 part by weight of lauryl mercaptan as a chain transfer agent were used as a compounding composition. To obtain an acrylic copolymer solution,
After measuring the molecular weight of the acrylic copolymer, an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 4, and the physical properties were measured. The results are shown in Table 2.

Example 6 As a compounding composition, 50 parts by weight of n-butyl acrylate, 47 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 0.02 part by weight of lauryl mercaptan as a chain transfer agent were used. Example 1 except that
In the same manner as above, an acrylic copolymer solution was obtained and the molecular weight of the acrylic copolymer was measured. Then, trimethylolpropane 1 as a crosslinking agent was added to 100 parts by weight of the solid content of the acrylic copolymer solution. 0.8 parts by weight of an adduct of 3 mol with tolylene diisocyanate (trade name: "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and styrene-based petroleum resin as a tackifying resin (trade name: "FTR manufactured by Mitsui Petrochemical Co., Ltd."
6100 ") and 20 parts by weight of acrylic acid were added, and an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 1 and its physical properties were measured. The results are shown in Table 2.

Comparative Example 4 As a compounding composition, without using lauryl mercaptan as a chain transfer agent, 95 parts by weight of n-butyl acrylate, 5 parts by weight of acrylic acid and 1 part of ethyl acetate as a solvent were used.
A total of 1 kg of 100 parts by weight was charged into a five-necked flask, and the reaction was started at 70 ° C. in the same manner as in Example 1. After the reaction at this temperature for 3 hours, the temperature of the reaction system is changed to the boiling point (about 85
C.) and reacted under reflux for 7 hours to obtain an acrylic copolymer solution. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1, an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 4, and the physical properties were measured. The results are shown in Table 2.

Comparative Example 5 As a compounding composition, without using lauryl mercaptan as a chain transfer agent, 93 parts by weight of n-butyl acrylate, 7 parts by weight of acrylic acid, and 1 part of ethyl acetate as a solvent were used.
50 parts by weight were charged into a five-necked flask in total of 1 kg,
An acrylic resin-based copolymer solution was obtained in the same manner as in Comparative Example 4. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1, an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 4, and the physical properties were measured. The results are shown in Table 2.

Comparative Example 6 As a compounding composition, 50 parts by weight of n-butyl acrylate, 47 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 3 parts by weight of acrylic acid were used without using lauryl mercaptan as a chain transfer agent. A total of 1 kg of 120 parts by weight of ethyl acetate was charged into a five-necked flask, and an acrylic copolymer solution was obtained in the same manner as in Comparative Example 4. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1,
An acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 6,
The physical properties were measured. The results are shown in Table 2.

[0054]

[Table 2]

As is clear from Table 2, in each of the examples of the present invention, both the storage elastic modulus at high temperature and the loss elastic modulus can be suppressed to a high level, and the exfoliation at high temperature can be maintained. The holding power is excellent and the low speed peel strength is dramatically improved. On the other hand, in each of the comparative examples, the adhesive performance at high temperature is inferior.

Example 7 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl methacrylate, and 0.02 of lauryl mercaptan as a chain transfer agent. An acrylic copolymer solution was obtained in the same manner as in Example 1 except that 1 part by weight was used. After measuring the molecular weight of this acrylic copolymer in the same manner as in Example 1, 1 mol of trimethylolpropane and 3 tolylene diisocyanate as crosslinking agents were added to 100 parts by weight of the solid content of the acrylic copolymer solution. Mole adduct (Nippon Polyurethane Co., Ltd .: trade name "Coronate L")
An acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that 0.8 part by weight was added, and the physical properties were measured. The results are shown in Table 3.

The shear holding force (120 ° C.) was 12 at room temperature, and the tape was attached to the SUS plate with a width of 20 mm.
After standing at 0 ° C. for 20 minutes, a load of 1 kg was applied in the shearing direction, and the deviation distance per unit time was measured.

Example 8 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl methacrylate and 0.05 parts of lauryl mercaptan as a chain transfer agent. An acrylic copolymer solution was obtained in the same manner as in Example 1 except that parts by weight were used, and the molecular weight was measured. Then, in the same manner as in Example 7, an acrylic pressure-sensitive adhesive tape was produced, and its physical properties were measured. Was measured. The results are shown in Table 3.

Comparative Example 7 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid and 0.2 parts by weight of 2-hydroxyethyl methacrylate were used without using lauryl mercaptan as a chain transfer agent. And 120 parts by weight of ethyl acetate as a solvent were charged into a five-necked flask in total of 1 kg, and the reaction was started at 70 ° C. in the same manner as in Example 1.
After the reaction for 3 hours at this temperature, the temperature of the reaction system was raised to the boiling point (about 85 ° C.), and the reaction was performed for 7 hours under reflux to obtain an acrylic copolymer solution. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1, an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 7, and the physical properties were measured. The results are shown in Table 3.

[0060]

[Table 3]

As is clear from Table 3, in each of the examples of the present invention, both the storage elastic modulus and the loss elastic modulus at high temperature can be suppressed to a high level, and the peeling at high temperature can be maintained. Excellent retention and shear retention. On the other hand, in the case of the comparative example, the adhesive performance at high temperature is inferior.

Example 9 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl methacrylate, and 0.02 of lauryl mercaptan as a chain transfer agent. An acrylic copolymer solution was obtained in the same manner as in Example 1 except that 1 part by weight was used. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1, the solid content of the acrylic copolymer solution was 100.
Addition product of 1 mol of trimethylolpropane and 3 mol of tolylene diisocyanate as a cross-linking agent with respect to parts by weight (manufactured by Nippon Polyurethane Co., Ltd .: trade name "Coronate L") 0.8
Parts by weight and special rosin ester as a tackifying resin (Arakawa Chemical Co., Ltd .: trade name "Super Ester A-115")
This acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that 20 parts by weight was added, and the physical properties were measured. The results are shown in Table 4.

The PE adhesion was measured by the same method as the SP adhesion except that a clean polyethylene plate was used instead of the SUS plate. Example 10 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl methacrylate, and 0.02 part by weight of lauryl mercaptan as a chain transfer agent. In the same manner as in Example 1 except that the above was used, an acrylic copolymer solution was obtained, the molecular weight was measured, and then an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 9, and the physical properties were measured. .. The results are shown in Table 4.

Comparative Example 8 As a compounding composition, 95 parts by weight of n-butyl acrylate, 4.8 parts by weight of acrylic acid and 0.2 parts by weight of 2-hydroxyethyl methacrylate were used without using lauryl mercaptan as a chain transfer agent. And 120 parts by weight of ethyl acetate as a solvent were charged into a five-necked flask in total of 1 kg, and the reaction was started at 70 ° C. in the same manner as in Example 1.
After the reaction for 3 hours at this temperature, the temperature of the reaction system was raised to the boiling point (about 85 ° C.), and the reaction was performed for 7 hours under reflux to obtain an acrylic copolymer solution. After measuring the molecular weight of the acrylic copolymer in the same manner as in Example 1, an acrylic pressure-sensitive adhesive tape was produced in the same manner as in Example 9, and the physical properties were measured. The results are shown in Table 4.

[0065]

[Table 4]

As is clear from Table 4, in each of the examples of the present invention, both the storage elastic modulus and the loss elastic modulus at high temperature can be suppressed to a high level, and the peeling at high temperature can be maintained. Excellent retention and shear retention. In addition, it has excellent adhesive performance to non-polar substances. On the other hand, in the case of the comparative example, the adhesive performance at high temperature is inferior.

[0067]

[Effect] Since the acrylic pressure-sensitive adhesive composition of the present invention is configured as described above, it is possible to impart heat resistance without increasing the glass transition point of the polymer, and to provide cold resistance and heat resistance. It can be designed as a high performance adhesive with both capabilities.

Since the acrylic pressure-sensitive adhesive tape, label or sheet of the present invention uses the above-mentioned acrylic pressure-sensitive adhesive composition, it can sufficiently withstand a high temperature of 150 ° C. or higher, and can be used for electric and electronic materials. It can be preferably used in the field.

Claims (2)

[Claims] 1. A general formula: (In the formula, R ₁ is hydrogen or a methyl group, and R ₂ has ₂ carbon atoms.
~ 18 alkyl groups) one or more monomers 7
The main component is an acrylic copolymer having 0 to 99.9% by weight and 0.1 to 30% by weight of another monomer copolymerizable with these monomers. , Weight average molecular weight (Mw) and number average molecular weight (Mn)
And the polydispersity (Mw / Mn) is 4 or less. 2. A pressure-sensitive adhesive tape, label or sheet comprising the acrylic pressure-sensitive adhesive composition according to claim 1.