JP2003268298A - Heat-resistant adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive usable under the environment of high temperature, whose adhesive strength is proper to surely fix a low rigidity material to a supporter when the material is subjected to processing and to easily separate it after the processing without giving damage and deformation thereto, and, in addition, no adhesive sticks or remains onto the separated material. <P>SOLUTION: The heat-resistant adhesive is composed mainly of a (meth) acrylic compound obtained by copolymerizing a monomer containing an acryloyl or methacryloyl group with a monomer containing a polar group and having an average molecular weight of 100,000-2,000,000, and a crossliking agent. The adhesive strength of its adhesive layer is 0.1-3.5 N/25 mm by JIS Z0237 after the treatment of heating for 6 hours at 180°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive which can be used in a high temperature environment.

[0002]

2. Description of the Related Art A material having low rigidity such as a plastic film or a thin glass plate is liable to be broken, or is bent during processing such as cutting or conveying, and cannot be kept flat. It is processed by fixing it to a support that can be made. As the fixing means, a method such as suction fixing or fixing with an adhesive is adopted because it can be easily attached and detached.

[0003] However, in the case of suction fixation, a shift may occur during work, or the material may be deformed or deformed depending on the strength of suction.
It may be damaged.

Further, in the method of fixing to a support with an adhesive, the support is peeled off under severe conditions such as high temperature treatment, or conversely, it is difficult to remove the support after fixing, and the support is deformed during the removal.・ It was sometimes damaged.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object thereof is to support a material having low rigidity such as a thin glass plate or a plastic film during processing. If it is necessary to firmly fix it to the body and peel it from the support after processing,
To provide a pressure-sensitive adhesive that can be fixed with an appropriate strength that can be peeled very easily without damaging or deforming the material, and that can be used in a high temperature environment that does not adhere to or remain on the material after peeling. It is in.

[0006]

Means for Solving the Problems That is, the present invention has an average molecular weight of 100,000 to 100,000 obtained by copolymerizing an acryloyl group- or methacryloyl group-containing monomer and a polar group-containing monomer.
2 million (meth) acrylic compounds and cross-linking agent as main components, J after heat treatment after heat treatment at 180 ° C for 6 hours
The adhesive strength of the adhesive layer according to IS Z 0237 is 0.
The heat-resistant pressure-sensitive adhesive according to claim 1, wherein the heat-resistant pressure-sensitive adhesive is 1 to 3.5 N / 25 mm. (2) The polar group of the polar group-containing monomer is a carboxyl group,
The heat-resistant adhesive according to claim 1, which is a polar group selected from a hydroxyl group and an amino group. Is.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the heat-resistant adhesive of the present invention will be described in detail. The present inventors have conducted various studies so as to be able to maintain appropriate tackiness even in a high temperature environment, and as a result, crosslink a (meth) acrylic copolymer having an average molecular weight of 100,000 to 2,000,000. It was confirmed that the above objectives could be achieved.

[0008] JIS Z 0237 has an adhesive force that does not cause floating or peeling during processing and is easy to attach and detach after processing.
It is preferable that the adhesive strength is in the range of 0.1 to 3.5 N / 25 mm, and more preferably 1.5 to 3.3 N / 25.
mm, most preferably 2.0 to 3.0 N / 25 mm. The heat-resistant pressure-sensitive adhesive of the present invention is excellent in heat resistance, especially holding power at high temperature, and bonds the material and the support with necessary and sufficient adhesive strength. Moreover, this adhesive strength does not become excessively high due to heating. Therefore, when it becomes necessary to peel the material from the support, it can be peeled very easily without damaging or deforming the material, and the adhesive does not easily remain on the material. It has a unique feature.

The (meth) acrylic copolymer used in the present invention is a copolymer of an acryloyl group- or methacryloyl group-containing monomer and a polar group-containing monomer. By adding the polar group-containing monomer, the pressure-sensitive adhesive of the present invention can obtain sufficient adhesion to a support, particularly a glass substrate. Examples of the acryloyl group- or methacryloyl group-containing monomer include 2-ethylhexyl acrylate and cyclohexyl acrylate, but are not particularly limited thereto.

The polar group-containing monomer used in the present invention includes acrylic acid, methacrylic acid, dimethyl acrylate, acrylonitrile and the like, and has polar groups such as carboxyl group, hydroxyl group and amino group in the molecule. Polymerizable unsaturated monomers are preferable, such as 2-hydroxyethyl acrylate, β-carboxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylonitrile, methacrylonitrile, and N-vinyl-2-pyrrolidone. Is mentioned.

The (meth) acrylic copolymer used in the present invention usually contains a repeating unit derived from the above polar group-containing monomer in an amount of 0.5 to 30% by weight, preferably 3 to 10% by weight.
It is desirable to have it in an amount of% by weight.

The average molecular weight of the (meth) acrylic copolymer used in the present invention is 100,000 to 2,000,000, preferably 500,000 to 1,000,000. When the average molecular weight of the (meth) acrylic copolymer is smaller than the minimum value, 18
It is not preferable because the holding power after heat treatment at 0 ° C. for 6 hours decreases. Further, when the average molecular weight is larger than the maximum value, there is no problem in characteristics, but it is difficult to mass-produce the (meth) acrylic copolymer, which is not preferable.

The above-mentioned (meth) acrylic copolymer can be obtained by a usual polymerization method such as radical polymerization, solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like for synthesizing an acrylic copolymer.

A crosslinking agent such as a polyisocyanate compound or an epoxy compound is added to the pressure-sensitive adhesive of the present invention in order to cure it by heat treatment. The addition amount of these crosslinking agents is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the above-mentioned (meth) acrylic copolymer. If the addition amount is less than the lower limit value, it is difficult to sufficiently complete the curing, and if the addition amount is more than 5.0 parts by weight, the holding power at high temperature may decrease.

The adhesive of the present invention has a rosin resin, a terpene resin, a coumarone resin, a phenol resin, a styrene resin, an aliphatic petroleum resin, in order to enhance the adhesive strength, within the range not impairing the object of the invention. A tackifier such as an aromatic petroleum resin or an aliphatic aromatic copolymer petroleum resin may be added.

In the present invention, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 to 50 μm. For the pressure-sensitive adhesive layer of the present invention, the pressure-sensitive adhesive is applied to a support as it is or after being made into a solution with a suitable organic solvent.
It can be obtained by drying by heat treatment or the like at -100 ° C for 30 seconds to 1 hour.

The pressure-sensitive adhesive of the present invention is provided with a pressure-sensitive adhesive layer on the surface of a support containing, for example, glass or plastic by a method such as coating, and an adherend such as a glass substrate or a plastic film via the pressure-sensitive adhesive layer. Can be used by temporarily fixing them by pasting them with a thermal laminating machine.

[0018]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 100 parts by weight of a copolymer having an average molecular weight of 600,000 obtained by copolymerizing 90 parts by weight of 2-ethylhexyl acrylate and 10 parts by weight of 2-hydroxyl acrylate which is a polar group-containing monomer. Against ethyl acetate 5
0 part by weight was sufficiently stirred at 25 ° C. to obtain 150 parts by weight of a mixed solution of an acrylic compound with ethyl acetate.

Next, 150 parts by weight of the above reaction solution (corresponding to 100 parts by weight of the acrylic copolymer) was added as a crosslinking agent with a polyisocyanate compound (Nippon Polyurethane: Coronate).
L) 0.5 part by weight was added and sufficiently stirred to obtain an adhesive of the present invention.

The pressure-sensitive adhesive obtained as described above was coated on a glass plate having a thickness of 0.7 mm whose surface was washed with a neutral detergent so that the coating thickness after drying was 20 μm, and the temperature was maintained at 80 ° C. for 10 minutes.
Allow to dry for minutes. Then, a 200 μm thick polyether sulfone (PES) film was used with a thermal laminator (manufactured by MKK Co., Ltd.), pressure: 0.7 MPa,
Temperature: 25 ° C. were laminated and adhered. The adhesive strength between the PES film and the glass substrate bonded in this way is determined by JI
The adhesive strength was measured according to SZ0237.

These were heated in an oven at 180 ° C. for 6 hours, and the peeling / floating of the film was observed during and after the heat treatment. Similarly, the adhesive strength between the heat-treated PES film and the glass substrate was measured according to JIS Z 0237. Then, the PES film was peeled from the glass plate by cooling at 25 ° C. for 3 minutes, and the ease of peeling at that time and the residual property (adhesive residue) of the adhesive on the PES substrate were visually observed and evaluated. Table 1 shows the evaluation results of each item.

Example 2 A sample was prepared in the same manner as in Example 1 except that the polar group-containing monomer was β-carboxyethyl acrylate, and the same items as in Example 1 were tested. The results are shown in Table 1.

Example 3 A sample was prepared in the same manner as in Example 1 except that 70 parts by weight of 2-ethylhexyl acrylate and 20 parts by weight of butyl acrylate were used as the acryloyl group-containing monomer. Was prepared, and the same items as in Example 1 were tested. The results are shown in Table 1.

Comparative Example 1 A sample was prepared in the same manner as in Example 1 except that 2-hydroxyl acrylate was not added, and the same items as in Example 1 were tested. The results are shown in Table 1.

[Comparative Example 2] In Example 1, the molecular weight was 50.
A sample was prepared in the same manner as in Example 1 except that 000 acrylic copolymer was used, and the same items as in Example 1 were tested. The results are shown in Table 1.

[Comparative Example 3] Instead of the adhesive layer prepared in Example 1, a joining tape (trade name: Y-4910) was used.
J, manufactured by Sumitomo 3M Ltd.) was used to prepare a sample in the same manner as in Example 1, and the same items as in Example 1 were tested. The results are shown in Table 1.

[0028]

[Table 1]

[0029]

EFFECTS OF THE INVENTION According to the present invention, glass, plastic, etc. to be adhered can be fixed to a support with necessary and sufficient adhesive strength during the process of processing, conveying and the like. The adhesive body can be processed in detail. Also,
Floating or peeling does not occur even under high temperature conditions, and the adhesive strength does not become excessively high due to heating or the like. Furthermore, when it becomes necessary to peel the adherend from the support, it is extremely easy to peel without damaging or deforming the adherend and leaving no adhesive on the support. Is possible.

Claims (2)

[Claims] 1. A main component is a (meth) acrylic compound having an average molecular weight of 100,000 to 2,000,000 obtained by copolymerizing an acryloyl group- or methacryloyl group-containing monomer and a polar group-containing monomer, and a crosslinking agent at 180 ° C. A heat-resistant pressure-sensitive adhesive characterized in that the pressure-sensitive adhesive layer according to JIS Z0237 after 6 hours of heat treatment has an adhesive strength of 0.1 to 3.5 N / 25 mm. 2. The heat-resistant adhesive according to claim 1, wherein the polar group of the polar group-containing monomer is a polar group selected from a carboxyl group, a hydroxyl group and an amino group.