JPS5850275B2 - Kanatsuseisetsuchiyakuzaino Seizouhou - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing pressure sensitive adhesives.

Pressure-sensitive adhesives have conventionally been generally produced by applying an adhesive substance in the form of a solution or emulsion onto a base material such as a tape or sheet.

However, the so-called solution coating method requires the use of a large amount of organic solvent, which has the disadvantage of causing problems such as flammability and toxicity, as well as contributing to air pollution.

Furthermore, the so-called emulsion method, which is a coating method in an emulsion state, generally has the disadvantage that the adhesive substance has poor water resistance and has problems such as corrosiveness to metals.

Furthermore, both of these two methods require a large amount of heat to remove the dispersion medium using heat, and cannot be applied directly to substrates that are not heat resistant.

Recently, however, some attempts have been made to produce adhesives without solvents by irradiating them with ultraviolet rays or ionizing radiation, but they have not yielded highly adhesive products and are still insufficient for practical use. be.

The present invention provides a method for producing a pressure-sensitive adhesive that does not have the drawbacks of the above two methods and has excellent adhesive properties.

The method of the present invention comprises: 1 100 parts by weight of an acrylic compound represented by the formula CH2=C-C00R2 (where R1 is hydrogen or a methyl group, R2 is an alkyl group having 4 or more carbon atoms), diacetone acrylamide or an ester moiety with a hydroxyl group. 1 to 100 parts by weight of acrylic acid or methacrylic acid ester, and a polymer of acrylic acid ester or methacrylic acid ester or acrylic acid ester or methacrylic acid ester and vinyl monomer. A pressure-sensitive adhesive is obtained by polymerizing the adhesive in substantially the absence of a solvent.

R2 of the acrylic compound represented by the above formula may essentially be any alkyl group having 4 or more carbon atoms, but it is usually an alkyl group with 4 carbon atoms such as butyl, hexyl, octyl, dodecyl, etc.
-12 alkyl groups are preferably used.

Such acrylic compounds include butyl acrylate, 2
-Ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, etc.

One component blended into such an acrylic compound is diacetone acrylamide or an ester of acrylic acid or methacrylic acid having a hydroxyl group in the ester moiety, and these are used in an amount of 1 to 100 parts by weight per 100 parts by weight of the acrylic compound of the above formula. It is blended.

Although the number of carbon atoms in the alkyl group of this ester moiety may essentially be any, it is usually selected from 1 to 12 carbon atoms.

These components have a remarkable effect on improving the adhesiveness of the product, but if they are less than 1 part by weight per 100 parts by weight of the acrylic compound, sufficient adhesiveness cannot be obtained;
If it is more than 0 parts by weight, the initial adhesive strength of the adhesive will decrease and the copolymerizability will be insufficient, which is not preferable.

The essence of the present invention is that a predetermined polymer is further blended.

This polymer mainly has the functions of adjusting viscosity and improving adhesiveness, and is selected from polymers having an acrylic ester or methacrylic ester unit as one essential monomer unit.

This seven unit is usually 2 of the total monomer unit of the polymer.
It may be 0% or more, preferably 50% or more, and an appropriate vinyl monomer can be selected as the other monomer unit to be combined with this.

Such polymers include, for example, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, poly 2-ethylhexyl acrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, poly 2-ethylhexyl methacrylate. These include homopolymers of acrylic acid or methacrylic esters, such as acrylic acid esters, and copolymers of acrylic esters and ethylenically unsaturated compounds.

Those skilled in the art can select the amount of the acrylic polymer to be added in order to obtain a viscosity suitable for various coating methods.

It is also possible to use a polymerization accelerator in combination, and common radical polymerization accelerators such as dimethylaniline, diethylaniline, zinc chloride, etc. can be used as appropriate.

Of course, various plasticizers, fillers, adhesion promoters, etc. can also be appropriately added to the composition of the present invention.

As the polymerization method, conventionally known methods using irradiation with ultraviolet rays, electron beams, etc. can be appropriately employed.

Generally, the composition is applied to paper by a known method such as knife coating, roll coating, dip coating, etc.
Preferably, the method is applied by applying it to various base materials such as synthetic resin films, protecting it with release-treated paper or film if necessary, preventing direct contact with oxygen, and irradiating it with ultraviolet rays or the like.

Note that the above composition has a low crosslink density when polymerized and crosslinked because it contains the acrylic compound represented by the above formula.

Therefore, the pressure sensitive adhesive of the present invention has high tackiness.

The adhesive strength of the pressure-sensitive adhesive of the present invention varies depending on the adherend and the composition, but it is at least 250 g/l 1 m or more for stainless steel, and is compared to conventional pressure-sensitive adhesives that are irradiated with ultraviolet rays or electron beams. It showed excellent adhesion.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto.

The pressure-sensitive adhesive obtained by the present invention polymerizes on the base material or release paper in the substantially absence of a solvent, so there are no problems such as flammability, toxicity, or contamination of the working environment, and sufficient adhesion is achieved. You can gain strength.

Also, unlike the emulsion method, the adhesive has good water resistance and there is no problem with corrosiveness to metals.

Furthermore, the pressure-sensitive adhesive of the present invention has various characteristics such as sufficient adhesive strength.

Example 1 One part of 2-ethylhexyl acrylate was added to 80 parts by weight of a monomer containing 100 parts by weight of 2-ethylhexyl acrylate and 10 parts by weight of diaseptone acrylamide.
20 parts by weight of a binary copolymer obtained from 00 parts by weight and 48 parts by weight of vinyl acetate were mixed with 1 part by weight of benzoin, 15 parts by weight of benzophenone O, and 0 parts by weight of diethylaniline.
．． An adhesive composition was prepared by adding 5 parts by weight.

Next, the adhesive composition was applied onto a polyester film having a thickness of 50 μm so that the coating thickness was 25 μm, and this coated sheet was coated with a 45 μm film at a distance of 20 cm in a nitrogen atmosphere.
The adhesive composition was polymerized and crosslinked by irradiating it with ultraviolet rays for 10 minutes using a 0W high-pressure mercury lamp.

An adhesive tape was made by cutting the sheet coated with this adhesive into a width of 15 mm, and a 180° beer test was performed according to J15-Z-1522 to measure the adhesive strength, and the adhesive strength was 300 g. /l 5+u.

*1800 peel test refers to adhesive tape being attached to a stainless steel plate, the rubber roll at 2 o'clock being moved back and forth twice, and then the adhesive tape being folded back at 180 degrees to the test panel.
This is a method of peeling at a speed of 300 mm/van and measuring the peeling force at this time.

Example 2 An adhesive composition was polymerized and crosslinked in the same manner as in Example 1 except that the monomer composition in Example 1 was replaced with 100 parts by weight of 2-ethylhexyl acrylate and 30 parts by weight of diaseptone acrylamide. An adhesive tape was prepared and the adhesive strength was measured using the method described above, and it was found to be 390 g/15 mm.

Example 3 100 parts by weight of 2-ethylhexyl acrylate and 2-
30 parts by weight of a binary copolymer of 100 parts by weight of 2-ethylhexyl acrylate and 35 parts by weight of todia-7ton acrylamide were blended with 70 parts by weight of a monomer obtained by blending 40 parts by weight of hydroxyethyl acrylate. ,
An adhesive composition was prepared by adding 1 part by weight of benzoin and 1 part by weight of diethylaniline.

Next, this adhesive composition was applied uniformly to a thickness of 25 μm on a release paper whose surface had been siliconized, and the adhesive composition was irradiated with a 600W high-pressure mercury lamp from a distance of 20 cm in a nitrogen atmosphere for 7 minutes. was polymerized and crosslinked on release paper.

Next, a 50μ soft vinyl chloride film was laminated on the surface of this adhesive, and the adhesive was transferred to the film base material to create an adhesive sheet covered with release paper.

This adhesive sheet was cut into 15 strips to make tape pieces for measuring adhesive strength, and the adhesive strength was measured at 500 g/15
It was a.

Claims (1)

[Claims] 1h. 100 parts by weight of an acrylic compound represented by the formula CH2=C-C00R2 (wherein R1 is hydrogen or a methyl group, and R2 is an alkyl group having 4 or more carbon atoms) and diacetone acrylamide or an ester moiety. A composition comprising 1 to 100 parts by weight of an ester of acrylic acid or methacrylic acid having a hydroxyl group, and a polymer of an acrylic ester or methacrylic ester or an acrylic ester or methacrylic ester and a vinyl monomer, A method for producing a pressure-sensitive adhesive, which comprises providing it on a base material or release paper and polymerizing it in substantially the absence of a solvent.