JPH1060400A - Self-adhesive composition and curing tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-adhesive compsn. which has a good self-adhesive power while hardly damaging an adherend and not remaining on it when peeled off and to provide a curing tape prepd. by using the same. SOLUTION: This compsn. comprises 100 pts.wt. acrylic ester copolymer obtd. by copolymerzing 80-99.9wt.% (meth)acrylic ester monomer having a 4-12C alkyl group, 0.1-4wt.% carboxylated polar monomer copolymerizable with the (meth)acrylic ester monomer, and 0-19.9wt.% other monomer copolymerizable with the foregoing monomers and 1-25 pts.wt. tackifying resin having a softening point of 95-160 deg.C and has a strength of self-adhesion to stainless steel (according to JIS Z0237.8) of 600-1300g/25mm and a strength of adhesion to polyethylene of 400-1,000g/25mm. This curing tape comprises a substrate and a self-adhesive layer formed thereon from the compsn. The compsn. is suitable for forming a self-adhesive layer of a curing tape, and the curing tape is excellent in hiding properties or protecting effects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pressure-sensitive adhesive composition which has good adhesive strength, causes little damage to a substance to be adhered upon peeling, and has no adhesive residue, and a curing tape using this pressure-sensitive adhesive composition ( Alternatively, the present invention relates to a curing sheet, and in the present invention, a curing tape and a curing sheet are collectively referred to as “curing tape”.

[0002]

2. Description of the Related Art Curing tapes have been used to cover and / or protect untreated parts when spraying or painting mortar or the like onto buildings.

[0003] The adhesive used in such a curing tape exhibits excellent adhesive performance to a surface formed of various materials such as wood, metal, glass, and concrete when the curing tape is applied. is required. Then, after the work is finished, this curing tape is peeled off,
Without damaging the surface of the adherend during this peeling,
Moreover, it is necessary that there is no adhesive residue. That is, the adhesive for the curing tape has a good adhesive strength,
Two completely opposite properties of being easily peelable are required.

Conventionally, as the adhesive for such a curing tape, silicone oil, silicone oil,
By mixing a plasticizer or an emulsifier, etc., the adhesive strength was weakened to secure the properties required at the time of peeling. Further, the strength itself of the pressure-sensitive adhesive is reduced so as to secure characteristics required at the time of peeling.

However, the curing tape using such an adhesive generally has low adhesive strength at the time of adhesion, and the curing tape often peels off spontaneously during operation. Further, by using a microsphere adhesive, a property required at the time of peeling is ensured by spot bonding with the microsphere adhesive.

However, since the curing tape using this pressure-sensitive adhesive is point-adhesive, there is a problem that the concealing property is low as compared with the curing tape which is surface-adhesive.

[0007]

An object of the present invention is to provide a curing tape which has good adhesive strength, a high concealing property and / or a protective effect, does not damage an adherend when peeled off, and has no adhesive residue. It is intended to provide.

Another object of the present invention is to provide a pressure-sensitive adhesive composition capable of forming such a curing tape.

[0009]

SUMMARY OF THE INVENTION The pressure-sensitive adhesive composition of the present invention has 4 to 1 carbon atoms.
80 to 99.9% by weight of a (meth) acrylate monomer having an alkyl group of 2 and 0.1 to 0.1% of a polar group-containing monomer having a -COOH group and copolymerizable with the (meth) acrylate monomer. An acrylic ester polymer (A) obtained by copolymerizing 4% by weight of another monomer copolymerizable with the (meth) acrylate and the polar group-containing monomer in an amount of 0 to 19.9% by weight; ,
The acrylic ester-based copolymer (A) is composed of a tackifying resin (B) having a softening point of 95 to 160 ° C. in an amount of 1 to 25 parts by weight based on 100 parts by weight of the copolymer (A), and having a gel fraction of 30 to 70
6% by weight and has an adhesive strength to stainless steel of 6 as measured by an adhesive strength measurement method in accordance with JIS-Z-0237.8.
It is characterized in that its adhesion to polyethylene is within the range of 400 to 1000 g / 25 mm, and that it is within the range of 400 to 1000 g / 25 mm.

The curing tape of the present invention has a carbon number of 4 to
80 to 99.9% by weight of a (meth) acrylate monomer having an alkyl group of 12 and 0.1 to 0.1% of a polar group-containing monomer having a -COOH group and copolymerizable with the (meth) acrylate monomer. 4% by weight and 0 to 19.9% by weight of another monomer copolymerizable with the (meth) acrylate and the polar group-containing monomer.
Acrylic ester-based polymer (A) copolymerized in the amount of
And a tackifying resin (B) having a softening point of 95 to 160 ° C. in an amount of 1 to 25 parts by weight based on 100 parts by weight of the acrylate-based copolymer (A), and having a gel fraction of 30 ~
It is in the range of 70% by weight, and has an adhesive strength to stainless steel of 600 to 1300 g / 25 mm and an adhesive strength to polyethylene of 400 to 1000 g / 25 mm measured by an adhesive strength measurement method based on JIS-Z-0237.8. It is characterized in that the pressure-sensitive adhesive composition is applied on one surface of a film substrate.

The present invention comprises an acrylate polymer (A) mainly comprising a (meth) acrylate monomer having a specific alkyl group and a tackifier resin (B) having a specific softening point. The gel fraction is adjusted to be in the range of 30 to 70% by weight, for example, using a crosslinking agent.
It is an adhesive composition having an adhesive strength to stainless steel measured by an adhesive strength evaluation method based on SZ-0237.8 adjusted to 600 to 1300 g / 25 mm and an adhesive strength to polyethylene within a range of 400 to 1000 g / 25 mm.

The curing sheet obtained by coating such a pressure-sensitive adhesive composition on one surface of a support has not only low adhesive strength but also good adhesiveness and high concealing property and / or protective effect. Nevertheless, there is no damage to the adherend and no adhesive residue when peeling.

[0013]

Next, the pressure-sensitive adhesive composition of the present invention and a curing tape using the pressure-sensitive adhesive composition will be described in detail.

The pressure-sensitive adhesive composition of the present invention comprises an acrylic ester polymer (A) and a tackifier resin (B). The acrylate polymer (A) is a copolymer of a (meth) acrylate, a polar group-containing monomer, and another monomer.

The (meth) acrylate used in the present invention is a (meth) acrylate in which the alkyl group forming the ester group has 4 to 12 carbon atoms. Examples of such (meth) acrylates include butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and heptyl (meth) acrylate.
Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decanyl (meth) acrylate, undecanyl (meth) acrylate and dodecanyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isononyl (meth) acrylate it can.

Among these, 2-ethylhexyl (meth)
Acrylate, isononyl (meth) acrylate, butyl (meth) acrylate, and isooctyl (meth) acrylate are preferred.

The above-mentioned polar group-containing monomer is the above (meth)
It is a monomer copolymerizable with an acrylate ester and contains a -COOH group as a polar group. Examples of such a polar group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and the like.

Among these, acrylic acid, methacrylic acid and the like are preferable as the polar group-containing monomer. Examples of other monomers include 2-hydroxyethyl (meth)
Acrylate, vinyl acetate, styrene, divinylbenzene, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic amide, dimethylamide methacrylate, dimethylamide acrylate, stearyl (meth) acrylate and behenyl (meth)
Acrylate and the like can be mentioned.

The acrylate polymer (A) used in the present invention is obtained by converting the above (meth) acrylate to 80 to 80%.
It is used in an amount of 99.9% by weight, preferably 90 to 99.9% by weight, particularly preferably 90 to 99% by weight, and contains the polar group-containing monomer in an amount of 0.1 to 4% by weight, preferably 0.1 to 3% by weight. %, Particularly preferably in amounts of 1 to 3% by weight, the other monomers being 0 to 19.9% by weight, preferably
It is used in an amount of 0 to 9.9% by weight, particularly preferably 0 to 9% by weight. The total of these three components is 100% by weight.

By reducing the amount of polar groups introduced into the acrylate polymer, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention can be adhered to various adherends. Will be possible.

The above-mentioned monomer is usually dissolved or dispersed in an organic solvent such as toluene, xylene, benzene, hexane, heptane, ethyl acetate, butyl acetate, methyl isobutyl ketone, methyl ethyl ketone, acetone and alcohols. Or in the dispersion,
Under stirring, the polymerization initiator is added, and the acrylate polymer is heated to a temperature not higher than the boiling point of the solvent.
(A) can be obtained. The polymerization initiator used here may be either an inorganic or organic initiator, but when an organic solvent is used, the organic initiator is usually soluble in this organic solvent. Therefore, use an organic initiator such as azobisisobutyronitrile (hereinafter sometimes abbreviated as "AIBN") or benzyl peroxide (hereinafter sometimes abbreviated as "BPO"). Is preferred.

The acrylate polymer (A) thus obtained usually has a weight average molecular weight of 100,000 to 600,000,
Preferably it is in the range of 200,000 to 500,000 and the gel fraction is usually in the range of 0 to 5%. That is, the acrylate polymer (A) thus produced has a low crosslinking density at this time.

The acrylate polymer (A) thus obtained can be separated from the solvent and used in the next step, but is preferably used in the next step while being dissolved in the reaction solvent.

The pressure-sensitive adhesive composition of the present invention contains a tackifier resin having a specific softening point. The softening point of the tackifier resin used in the present invention needs to be in the range of 95 to 160 ° C., and the softening point is 100 to 1
It is preferably in the range of 60 ° C.
It is particularly preferred that it is in the range of ° C.

By using such a tackifying resin having a high softening point, the pressure-sensitive adhesive composition of the present invention is required to have a good adhesive strength, especially as a curing tape when used as a pressure-sensitive adhesive for a curing tape. Adhesive strength can be secured.

Examples of the tackifying resin used in the present invention include rosin-based resins, terpene-based resins, terpene-phenol-based resins and pentane-based resins stabilized by disproportionation, hydrogenation or polymerization. Examples include petroleum-based resins (eg, modified xylene resins).

The tackifier resin is used in an amount of 1 to 25 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the acrylate polymer (A). Is done. If the amount of the tackifying resin is less than 1 part by weight, sufficient tackiness cannot be ensured. If the amount is more than 25 parts by weight, adhesive residue may be generated when the resin is peeled off. Depending on the case, peeling may occur during application and sufficient concealing properties and / or protective effects may not be obtained.

The pressure-sensitive adhesive composition of the present invention has a gel fraction of 3
It is in the range of 0-70%, preferably in the range of 40-60%. By adjusting the gel fraction within the above range, good releasability is exhibited.

The gel fraction of the pressure-sensitive adhesive composition of the present invention is a value obtained by immersing a sample in a toluene solvent, filtering the toluene insoluble matter, and measuring the weight percentage of the insoluble matter relative to the total amount of the sample. The above-mentioned range can be adjusted by blending, for example, a reaction curing agent or the like with the acrylate polymer and the tackifier resin to form a crosslinked structure.

Examples of the reaction curing agent used here include:
Examples thereof include a polyisocyanate-based curing agent, an epoxy-based curing agent, a metal salt chelating agent-based curing agent, a melamine-based curing agent, and a peroxide-based curing agent. For example, the polyisocyanate compound used as a curing agent in the present invention may be a polyisocyanate-based compound that is generally used as a curing agent for a resin. Representative examples of such a polyisocyanate-based curing agent include the following. Compounds having the structure as described can be used.

[0031]

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As a typical example of the epoxy-based curing agent, a compound having the following structure can be used.

[0033]

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The amount of the reaction hardener used is adjusted so that the gel fraction of the pressure-sensitive adhesive composition falls within the above range. That is, the amount of the reaction curing agent is used, since the gel fraction of the obtained pressure-sensitive adhesive composition varies significantly depending on the type of the reaction curing agent, so that the gel fraction of the pressure-sensitive adhesive composition falls within the above range. It can be selected as appropriate.

Although the method for adjusting the gel fraction using a reaction hardener has been described above, the gel fraction may be adjusted to fall within the above range by another method. After blending the above reaction curing agent, by aging the pressure-sensitive adhesive composition of the present invention under mild conditions for about 1 to 15 days, for example, at room temperature,
A crosslinked structure can be formed uniformly.

The thus formed pressure-sensitive adhesive composition is usually dissolved in a solvent before aging, applied, dried and then aged. And the adhesive composition of the present invention has an adhesive force measured by an adhesive force test method based on JIS-Z-0237.8, which is 600 to 1300 for stainless steel.
g / 25mm, 400-1000g / 25 for polyethylene
It is necessary to be within the range of 600 to 1200 g / 25 mm for stainless steel and 400 to 800 g / 25 mm for polyethylene.

The adhesive strength in the above range belongs to medium to high adhesive strength (adhesive strength) as an adhesive, and due to such adhesive strength, peeling or lifting occurs during application of the curing tape. do not do. Then, when peeling, there is no adhesive residue on the surface of the adherend, and no damage is caused to the adherend at the time of peeling.

The adhesive strength specified in the pressure-sensitive adhesive composition of the present invention is a value evaluated by a measuring method in accordance with JIS-Z-0237.8, and specifically, a 25 μm-thick PET (polyethylene terephthalate) film. A sample coated with the pressure-sensitive adhesive composition so as to have a dry thickness of 25 μm is used. At this time, the type and the amount of the curing agent to be added to the pressure-sensitive adhesive composition to be applied can be appropriately selected so that a desired gel fraction can be obtained after aging.

The coated sample of the pressure-sensitive adhesive composition thus obtained was stuck on a stainless steel plate and a polyethylene plate in a standard state determined by JIS, and left as it was for 20 minutes. The peel angle was 180 ° and the peel speed was 300 mm. / min. and the peel strength per 25 mm width is measured. The peel strength measured here is defined as the adhesive strength specified in the present invention. This adhesive force is 600 to 130 for stainless steel.
0 g / 25 mm, preferably in the range of 600-1200 g / 25 mm, and 400-1000 for polyethylene.
When it is within the range of g / 25 mm, preferably 400 to 800 g / 25 mm, good hiding and / or protective effect and releasability are obtained.

The curing tape of the present invention is a tape in which a pressure-sensitive adhesive layer comprising the above-mentioned pressure-sensitive adhesive composition is formed on one surface of a substrate tape as a support. In this curing tape, the support can be formed of paper, plastic, metal foil, cloth, or the like. In the present invention, it is particularly preferable that the support be formed of plastic.

Examples of plastic materials from which the support can be formed include α-olefin (co) polymers such as polyethylene and polypropylene, polyvinyl chloride,
Examples thereof include polyvinyl acetate, polyethylene terephthalate, and ethylene / vinyl acetate copolymer.

The thickness of such a support is usually 10 to 1
000 μm. The pressure-sensitive adhesive composition can be directly applied to such a support surface, but the coating liquid containing the pressure-sensitive adhesive composition is applied to a separator or the like in advance, and after removing the solvent, the pressure-sensitive adhesive formed on the separator surface is removed. By transferring the layer to the surface of the support, the support can be prevented from being eroded by the solvent.

The thickness of the pressure-sensitive adhesive layer thus formed is usually 5 to 100 μm, preferably 10 to 60 μm.
Within the range. When this curing tape is wound and used, it is not necessary to particularly arrange a release paper or the like on the pressure-sensitive adhesive layer, but a release layer may be provided on the pressure-sensitive adhesive layer.

The curing tape of the present invention can be used as a masking tape for spraying a mortar or the like or spraying a paint, like a normal curing tape. In particular, the curing tape of the present invention has good adhesiveness to various adherends such as metal, wood, and plastic, has excellent concealing properties and / or protective effects, and has an adhesive residue when peeled after use. And less damage to the adherend during peeling.

[0045]

The pressure-sensitive adhesive composition of the present invention contains an acrylic ester polymer (A) having a specific composition and a tackifier resin (B) having a specific softening point, and has a specific gel fraction. By adjusting so as to have, the adhesive tape has a relatively high adhesive strength and is excellent in concealing properties and / or protective effects, but has no adhesive residue when peeled off, and is suitable as an adhesive for a curing tape.

The curing tape of the present invention has a pressure-sensitive adhesive layer composed of the above-mentioned pressure-sensitive adhesive composition laid on the surface of the support, and has excellent concealing properties and / or protective effects and, when peeled off. No glue residue etc.
Further, the adherend is hardly damaged.

[0047]

EXAMPLES Next, the pressure-sensitive adhesive composition and the curing tape of the present invention will be described with reference to examples, but the present invention is not limited thereto.

[0048]

Example 1 100 parts by weight of toluene were put into a flask, and 100 parts by weight of 2-ethylhexyl acrylate and methacrylic acid were mixed in a weight ratio of 98: 2 in the toluene, and stirred at 70 ° C. After heating to the reaction solution, the polymerization initiator azobisisobutyronitrile (AIBN)
0.5 part by weight was added, and polymerization was carried out at 70 ° C. for 10 hours to produce an acrylate polymer.

The weight average molecular weight of this acrylate polymer was 300,000, and the gel fraction measured as a toluene insoluble content was 0%. 200 parts by weight of a toluene solution of the acrylate polymer obtained as described above (acrylate polymer = 100 parts by weight)
Disproportionated rosin (polymerized rosin-based tackifying resin, softening point = 1
25 ° C, Rika Hercules Co., Ltd., Pentaline-CJ)
Was mixed in 20 parts by weight.

Next, an epoxy-based curing agent having a structure represented by the above formula (trade name: Tetrad X, manufactured by Mitsubishi Rayon Co., Ltd.) was added to the mixture (220 parts by weight) in an amount of 0.3.
Parts by weight were added.

The toluene solution of the pressure-sensitive adhesive composition thus obtained was dried, coated on the pressure-sensitive adhesive to a thickness of 25 μm, and dried. Adhesive tape for adhesive strength evaluation based on JIS-S-0237.8 by transferring the obtained coating film of the adhesive composition having a thickness of 25 μm onto a PET substrate having a thickness of 25 μm and aging at room temperature for 7 days. Specimens were manufactured.

A toluene solution of the pressure-sensitive adhesive composition obtained as a sample for evaluation as a curing tape was applied on a separator so that the pressure-sensitive adhesive thickness after drying was 40 μm.
Let dry. A coating film of the obtained pressure-sensitive adhesive composition having a thickness of 40 μm was coated on an OPP substrate (stretched polypropylene film substrate,
(Thickness: 70 μm), and aged at room temperature for 7 days to produce a curing tape of the present invention.

The gel fraction of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer transferred to the pressure-sensitive adhesive tape sample and the curing tape was 60%. Table 1 shows the results of measurement of the adhesive strength of this adhesive tape test specimen on a stainless steel plate and a polyethylene plate by an evaluation method in accordance with JIS-Z-0237.8.

Further, a stainless plate of this curing tape,
Table 1 also shows the results of measuring the adhesive strength of veneer boards and polyethylene boards by an evaluation method based on JIS-Z-0237.8. In addition, this curing tape is used for stainless steel plate, veneer plate,
It was adhered to the surface of a polyethylene plate, and the peeling during adhesion was visually observed. Furthermore, the cured tape was stuck at 70 ° C. for 120 hours, then peeled off, and the adhesive residue on the surface to be stuck was examined. The results are also shown in Table 1.

[0055]

Example 2 100 parts by weight of toluene were placed in a flask, and 100 parts by weight of 2-ethylhexyl acrylate, methacrylic acid, and 2-hydroxyethyl methacrylate were mixed in the toluene at a weight ratio of 97: 2: 1. Then, after heating to 75 ° C. with stirring, 0.5 part by weight of a polymerization initiator benzoyl peroxide (BPO) was added to the reaction solution,
Polymerization was performed at 75 ° C. for 10 hours to produce an acrylate polymer.

The weight average molecular weight of this acrylate polymer was 400,000, and the gel fraction measured as a toluene-insoluble component was 1%. 200 parts by weight of a toluene solution of the acrylate polymer obtained as described above (acrylate polymer = 100 parts by weight)
Terpene phenolic tackifying resin (softening point = 105
And 10 parts by weight of Tos-105 (produced by Yashara Chemical Co., Ltd.).

Next, 1.5 parts by weight of a polyisocyanate-based curing agent having a structure represented by the above formula (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) was added as a curing agent to the mixture (210 parts by weight). Was added.

The toluene solution of the pressure-sensitive adhesive composition thus obtained was dried, applied so that the pressure-sensitive adhesive thickness became 25 μm, and dried. Adhesive tape for adhesive strength evaluation based on JIS-S-0237.8 by transferring the obtained coating film of the adhesive composition having a thickness of 25 μm onto a PET substrate having a thickness of 25 μm and aging at room temperature for 7 days. Specimens were manufactured.

A toluene solution of the pressure-sensitive adhesive composition obtained as a sample for evaluation as a curing tape was applied on a separator so that the pressure-sensitive adhesive thickness after drying was 40 μm.
Let dry. The obtained coating film of the pressure-sensitive adhesive composition having a thickness of 40 µm was transferred onto an OPP base material (thickness: 70 µm) and aged at room temperature for 7 days to produce a curing tape of the present invention. The gel fraction of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer transferred to the pressure-sensitive adhesive tape sample and the curing tape was 60%.

With respect to the obtained pressure-sensitive adhesive tape specimen and the curing tape, the adhesive strength of the pressure-sensitive adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling were evaluated in the same manner as in Example 1. Table 1 shows the results.

[0061]

Example 3 100 parts by weight of toluene were placed in a flask, and 100 parts by weight of butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid were mixed in the toluene at a weight ratio of 60: 39: 1, and the mixture was stirred. After the mixture was heated to 70 ° C., 0.5 parts by weight of a polymerization initiator benzoyl peroxide (BPO) was added to the reaction solution.
The polymerization was carried out for an hour to produce an acrylate polymer.

The weight average molecular weight of this acrylate polymer was 350,000, and the gel fraction measured as toluene-insoluble content was 0%. 200 parts by weight of a toluene solution of the acrylate polymer obtained as described above (acrylate polymer = 100 parts by weight)
Terpene phenolic tackifying resin (softening point = 150
C., 10 parts by weight of Yashara Chemical Co., Ltd., G-150) were mixed.

Then, an epoxy-based curing agent having a structure represented by the above formula (trade name: Tetrad X, manufactured by Mitsubishi Rayon Co., Ltd.) was added to the above mixture (210 parts by weight) in an amount of 0.3.
Parts by weight were added.

The thus-obtained toluene solution of the pressure-sensitive adhesive composition was dried, coated so as to have a pressure-sensitive adhesive thickness of 25 μm, and dried. Adhesive tape for adhesive strength evaluation based on JIS-S-0237.8 by transferring the obtained coating film of the adhesive composition having a thickness of 25 μm onto a PET substrate having a thickness of 25 μm and aging at room temperature for 7 days. Specimens were manufactured.

A toluene solution of the pressure-sensitive adhesive composition obtained as a sample for evaluation as a curing tape was coated on a separator so that the pressure-sensitive adhesive thickness after drying was 40 μm.
Let dry. The obtained coating film of the pressure-sensitive adhesive composition having a thickness of 40 µm was transferred onto an OPP base material (thickness: 70 µm) and aged at room temperature for 7 days to produce a curing tape of the present invention. The gel fraction of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer transferred to the pressure-sensitive adhesive tape sample and the curing tape was 40%.

In the same manner as in Example 1, the obtained adhesive tape specimen and the curing tape were evaluated for the adhesive strength of the adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0067]

EXAMPLE 4 100 parts by weight of toluene were placed in a flask, and 2-ethylhexyl acrylate, vinyl acetate, methacrylic acid, and 2-hydroxyethyl methacrylate were added to the toluene in a weight ratio of 87: 10: 2: 1. After 100 parts by weight were mixed and heated to 70 ° C. with stirring, the reaction solution was added to a polymerization initiator benzoyl peroxide (BPO) at a concentration of 0.1%.
5 parts by weight were added, and polymerization was carried out at 70 ° C. for 10 hours to produce an acrylate polymer.

The weight average molecular weight of this acrylate polymer was 300,000, and the gel fraction measured as toluene-insoluble content was 0%. 200 parts by weight of a toluene solution of the acrylate polymer obtained as described above (acrylate polymer = 100 parts by weight)
10 parts by weight of a modified xylene-based tackifier resin (softening point = 120 ° C., Nikanol 120, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was mixed.

Next, as a curing agent, 1.5 parts by weight of a polyisocyanate-based curing agent having a structure represented by the above formula (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) was added to the mixture (210 parts by weight). Was added.

The toluene solution of the pressure-sensitive adhesive composition thus obtained was dried, applied so that the pressure-sensitive adhesive had a thickness of 25 μm, and dried. Adhesive tape for adhesive strength evaluation based on JIS-S-0237.8 by transferring the obtained coating film of the adhesive composition having a thickness of 25 μm onto a PET substrate having a thickness of 25 μm and aging at room temperature for 7 days. Specimens were manufactured.

A toluene solution of the pressure-sensitive adhesive composition obtained as a sample for evaluation as a curing tape was applied on a separator so that the pressure-sensitive adhesive thickness after drying was 40 μm.
Let dry. The obtained coating film of the pressure-sensitive adhesive composition having a thickness of 40 µm was transferred onto an OPP base material (thickness: 70 µm) and aged at room temperature for 7 days to produce a curing tape of the present invention. The gel fraction of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer transferred to the pressure-sensitive adhesive tape sample and the curing tape was 40%.

With respect to the obtained pressure-sensitive adhesive tape specimen and curing tape, the adhesive strength of the pressure-sensitive adhesive tape specimen and curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling were evaluated in the same manner as in Example 1. Table 1 shows the results.

[0073]

Comparative Example 1 In Example 1, the amount of the epoxy-based curing agent was 1.5 parts by weight, and the gel fraction of the pressure-sensitive adhesive composition was 85.
%, And a pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape specimen and a curing tape were produced in the same manner.

In the same manner as in Example 1, the obtained adhesive tape specimen and the curing tape were evaluated for the adhesive strength of the adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0075]

Comparative Example 2 The same procedure as in Example 1 was repeated except that the amount of disproportionated rosin (polymerized rosin) was changed to 40 parts by weight and the gel fraction of the pressure-sensitive adhesive composition was changed to 50%. An adhesive tape specimen and a curing tape were manufactured.

The obtained adhesive tape specimen and curing tape were evaluated in the same manner as in Example 1 for the adhesive strength of the adhesive tape specimen and curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0077]

Comparative Example 3 In Example 1, the ratio of 2-ethylhexyl acrylate and methacrylic acid (MAA) used in producing the acrylic ester polymer was changed to 95: 5.
An epoxy-based curing agent represented by the above formula is used as a curing agent in an amount of 0.1.
A pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape sample, and a curing tape were produced in the same manner except that 2 parts by weight were added.

In the same manner as in Example 1, the obtained adhesive tape specimen and the curing tape were evaluated for the adhesive strength of the adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0079]

Comparative Example 4 In Example 1, the amount of the epoxy-based curing agent was 0.06 parts by weight, and the gel fraction of the pressure-sensitive adhesive composition was 2.
A pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape sample, and a curing tape were produced in the same manner except that the content was adjusted to 0%.

In the same manner as in Example 1, the adhesive tape specimen and the curing tape obtained were evaluated for the adhesive strength of the adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0081]

Comparative Example 5 In Example 2, a terpene phenol-based tackifying resin having a softening point of 105 ° C. was replaced with a softening point of 85.
A pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape test sample, and a curing tape were produced in the same manner except that a terpene phenol-based tackifier resin (manufactured by Yasuhara Chemical Co., Ltd., To-85) was used.

With respect to the obtained pressure-sensitive adhesive tape specimen and the curing tape, the adhesive strength of the pressure-sensitive adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling were evaluated in the same manner as in Example 1. Table 1 shows the results.

[0083]

Comparative Example 6 In Example 2, the amount of the terpene phenol-based tackifying resin was changed to 40 parts by weight, and a polyisocyanate-based curing agent represented by the above formula was used as a curing agent.
A pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape sample, and a curing tape were produced in the same manner except that parts by weight were added.

With respect to the obtained pressure-sensitive adhesive tape specimen and the curing tape, the adhesive strength of the pressure-sensitive adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling were evaluated in the same manner as in Example 1. Table 1 shows the results.

[0085]

Comparative Example 7 The procedure of Example 3 was repeated except that the amount of the terpene phenol-based tackifying resin was changed to 20 parts by weight, and that the epoxy-based curing agent represented by the above formula was added in an amount of 0.4 part by weight. Thus, a pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape specimen, and a curing tape were produced.

In the same manner as in Example 1, the adhesive tape specimen and the curing tape obtained were evaluated for the adhesive strength of the adhesive tape specimen and the curing tape, the peeling during adhesion of the curing tape and the adhesive residue after peeling. Table 1 shows the results.

[0087]

[Table 1]

Claims (2)

[Claims] (1) 80 to 99.9% by weight of a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, having a -COOH group and copolymerizable with the (meth) acrylate monomer. Acrylic obtained by copolymerizing a polar group-containing monomer in an amount of 0.1 to 4% by weight and another monomer copolymerizable with the (meth) acrylate and the polar group-containing monomer in an amount of 0 to 19.9% by weight. An acid ester polymer (A) and a tackifier resin (B) having a softening point of 95 to 160 ° C. in an amount of 1 to 25 parts by weight based on 100 parts by weight of the acrylate ester copolymer (A). And the gel fraction is in the range of 30 to 70% by weight,
An adhesive composition characterized by having an adhesive strength to stainless steel of 600 to 1300 g / 25 mm and an adhesive strength to polyethylene of 400 to 1000 g / 25 mm measured by an adhesive strength measuring method based on SZ-0237.8. (2) 80 to 99.9% by weight of a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, having a -COOH group and copolymerizable with the (meth) acrylate monomer. Acrylic obtained by copolymerizing a polar group-containing monomer in an amount of 0.1 to 4% by weight and another monomer copolymerizable with the (meth) acrylate and the polar group-containing monomer in an amount of 0 to 19.9% by weight. An acid ester polymer (A) and a tackifier resin (B) having a softening point of 95 to 160 ° C. in an amount of 1 to 25 parts by weight based on 100 parts by weight of the acrylate ester copolymer (A). And the gel fraction is in the range of 30 to 70% by weight,
An adhesive composition having an adhesive force to stainless steel measured by an adhesive force measuring method based on SZ-0237.8 of 600 to 1300 g / 25 mm, and an adhesive force to polyethylene within a range of 400 to 1000 g / 25 mm, Curing tape characterized by being coated on one side.