JPS6219311B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for forming a surface protective layer on the surface of an adherend, and more specifically, the present invention relates to a method for forming a surface protective layer on an adherend, and more specifically, the present invention relates to a method for forming a surface protective layer on an adherend, and more specifically, it relates to a method for forming a surface protective layer on an adherend, and more particularly, it relates to a method for forming a surface protective layer on an adherend, and more particularly, it relates to a method for forming a surface protection layer on an adherend, and more particularly, it relates to a method for forming a surface protective layer on an adherend, and more particularly, it relates to a method for forming a surface protective layer on an adherend, and more particularly, it relates to a method for forming a surface protective layer on an adherend. The present invention provides a method for forming a surface protective layer to semi-permanently prevent such occurrence. Conventionally, the surface of adherends such as plate-shaped articles has been protected by temporarily applying a surface protection adhesive film before processing, and then applying paint after processing. It is common for there to be. These series of steps begin with pasting the film onto a plate-shaped article, followed by bending, drawing, and
The process involves processing such as punching, followed by film peeling, surface cleaning, painting, and drying, which is not only complicated, but also requires safety because the cleaning fluid and paint contain large amounts of organic solvents. Or there were various hygiene problems. Accordingly, a first object of the present invention is to provide a method for forming a surface protective layer that can easily protect the surface of a plate-shaped article before processing and protect the surface after processing. A second object of the present invention is to provide a method for forming a surface protective layer by a simple operation without using an organic solvent during construction. The object of the present invention is to provide a self-supporting sheet (or film) containing a photopolymerizable compound having at least one (meth)acryloyl group in the molecule, a photosensitizer, and a base polymer. A composite sheet (or film) formed with a photocurable adhesive layer is laminated onto the surface of an adherend via the adhesive layer, the adhesive layer is cured by backlight irradiation, and then the self-supporting adhesive layer is cured. This is achieved by peeling off only the sheet (or film) and forming a surface protective layer made of a cured polymer on the surface of the adherend. According to the method of the present invention, damage to the surface of an adherend such as a plate-shaped article before and during processing is prevented by pasting the composite sheet,
After processing, it is protected by a surface protection layer formed by polymerizing and curing the photocurable adhesive layer by irradiating it with light.
The surface of the adherend will not be damaged. A photopolymerizable compound having at least one (meth)acryloyl group in the molecule used in carrying out the present invention refers to a photopolymerizable compound having at least one (meth)acryloyl group in the molecule as a polymerizable double bond. , preferably two or more, such as 1,4-butylene glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate. , polyethylene glycol di(meth)acrylate,
Examples include monomers such as trimethylolpropane tri(meth)acrylate and tetramethylolmethanetetra(meth)acrylate, and oligomers such as epoxy acrylate, urethane-modified acrylate, and oligoester acrylate.
These may be used in combination of two or more types as necessary. In addition, base polymers can be divided into those that have adhesive properties themselves and those that exhibit the necessary adhesive properties by blending the photopolymerizable compound. number is 1
~12 (meth)acrylic acid alkyl ester polymers, (meth)acrylic acid alkyl esters and (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, styrene, vinyl acetate, A binary or tertiary copolymer formed by copolymerizing with an unsaturated compound such as (meth)acrylonitrile (including a polymer formed by crosslinking using a crosslinking agent), or a styrene-isoprene-styrene block copolymer Examples include rubber-based adhesive substances mainly composed of rubbers such as rubber, styrene-butadiene rubber, and nitrile-butadiene rubber. Examples of the latter include saturated or unsaturated polyester resins, polybutyral resins, and the like. The blending ratio of the photopolymerizable compound and the base polymer is 80:20 to 10:90, preferably 70:30 to 30:70.
(Each is a weight ratio), and if the content of the compound exceeds 80%, the cohesiveness of the photocurable adhesive layer before light irradiation will be poor, and the adhesive will ooze out to the side surfaces, which is undesirable. Moreover, if it is less than 10%, sufficient curing cannot be obtained, which is not preferable. The photosensitizer is not particularly limited as long as it promotes the photopolymerization reaction of the compound, but examples include benzoyl, benzoyl methyl ether,
Benzoins such as benzoin ethyl ether, benzoin isopropyl ether, and α-methylbenzoin; anthraquinones such as 1-chloroanthraquinone and 2-chloroanthraquinone; benzphenones such as benzophenone, p-chlorobenzophenone, and p-dimethylaminobenzophenone; and sulfur-containing compounds such as diphenyl disulfide and tetramethylthiuram disulfide. It is preferably added in an amount of 0.5 to 10% by weight. In this way, a photocurable adhesive composition composed of a photopolymerizable compound, a photosensitizer, and a base polymer,
Colored or colorless transparent self-supporting sheets (or films) that transmit light, such as polyvinyl chloride sheets or films, polyolefin sheets or films (sheets or films made of ethylene-vinyl acetate copolymer and its saponified product) include)
Polyester sheet or film (thickness is 10~
(preferably 300 μm) on one side with a thickness of about 1~
It is coated or transferred in a range of 100 μm to form a photocurable adhesive layer, but appropriate amounts of other compounding agents can be added to the composition depending on the purpose. Examples of compounding agents include polymerization inhibitors that prevent thermal polymerization during production and reactions during storage, such as hydroquinone, hydroquinone monomethyl ether, and tert-
Butylcatechol, p-benzoquinone, 2.5-
tert-butylhydroquinone, phenothiazine, pigments for coloring or decoration such as zinc white, yellow lead, red red iron, dyes such as toluidine red, phthalocyanine blue, phthalocyanine green, other metal powders, glass beads,
Examples include glass powder, glass flakes, etc., and adhesion-imparting resins such as xylene resin and coumaron resin for the purpose of improving adhesion to the surface of the adherend. A composite sheet (or film) consisting of a self-supporting sheet (or film) and a photocurable adhesive layer constructed in this way can be used in the form of a plate made of a metal plate, glass plate, wood board, decorative board, plastic board, etc. It is attached to the surface of an adherend such as an article via an adhesive layer. Generally, self-supporting sheets (or films) are used to produce high-pressure mercury lamps, ultra-high pressure mercury lamps,
The adhesive layer is photopolymerized and cured by irradiating it with light for 0.3 seconds or more, preferably 3 seconds or more using a light source such as a metal halide lamp, carbon arc lamp, or xenon lamp. Then the support sheet (or film)
By peeling only the adhesive, a surface protective layer made of a cured polymer is formed on the surface of the adherend. Peeling of the support sheet (or film) after curing is due to the plastic flow of the adhesive layer at the time of peeling. This can be easily done from the adhesive layer that has been lost. It will be understood that the light irradiation may be performed after the composite sheet is attached to an adherend such as a plate-shaped article, before or after the adherend is processed. As described above, according to the method of the present invention, by irradiating the composite sheet used for surface protection of the adherend surface with light and peeling off the self-supporting sheet, the surface protective layer can semi-permanently protect the surface. It has the characteristic of being able to form. Of course, the method of the present invention can be used simply to form a surface protective layer on the surface of an article, regardless of the processing of the adherend. Next, examples of the present invention will be shown. The text middle part means the weight part. Example 1 2-Ethylhexyl acrylate 50 parts Methyl methacrylate 50 Methacrylic acid 2 Benzoyl perkiside 0.2 Ethyl acetate 100 The above blended composition was polymerized in a conventional manner to obtain an acrylic copolymer. Next, to 50 parts of the copolymer (solid content), 50 parts of tetraethylene glycol dimethacrylate,
7 parts of benzophenone, 2 parts of a reaction product of 3 moles of tolylene diisocyanate and 1 mole of 1,1,1-trimethylol, and 0.01 part of hydroquinone were mixed uniformly and coated on one side of a 60 μm thick polyethylene sheet after drying. The composite sheet was coated to a thickness of 5 μm and dried at 100° C. for 5 minutes to obtain a composite sheet. Example 2 Vinyl acetate 60 parts Methyl methacrylate 20 Ethyl acrylate 20 Azobisisobutyronitrile 0.05 Ethyl acetate 100 The above blended composition was polymerized by a conventional method to obtain an acrylic copolymer. Next, to 70 parts (solid content) of the copolymer, 30 parts of tetramethylolmethanetetraacrylate, 3 parts of benzoin methyl ether, and hydroquinone
Blend 0.01 part and mix uniformly, and apply it to one side of a 60 μm thick polyvinyl chloride sheet to a dry thickness of 5 μm.
m and dried at 100°C for 5 minutes to obtain a composite sheet. Example 3 Styrene-isoprene-styrene block copolymer rubber (manufactured by Ciel Chemical Co., Ltd., trade name: Kraton)
1107) 60 parts acrylated butadiene oligomer at both ends (manufactured by Idemitsu Petrochemical Co., Ltd., trade name PolyBD-R45ACR-LC)
40〃 Benzophenone 7〃 Hydroquinone 0.01〃 The above blended composition was dissolved in toluene to create a 30% toene solution, and this was applied to the surface of a polyethylene sheet with a thickness of 60 μm so that the thickness after drying was 5 μm. A composite sheet was obtained by drying at ℃ for 5 minutes. Example 4 Saturated polyester resin (manufactured by Toyobo Co., Ltd., trade name: Vylon) 40 parts Epoxy acrylate (manufactured by Showa Kobunshi Co., Ltd., trade name: Lipoxy SP-1507) 60〃 Benzophenone 7〃 Hydroquinone 0.01〃 Dissolve the above blended composition in toluene A 30% toluene solution was prepared, and this was applied to a polyvinyl chloride sheet with a thickness of 60 μm so that the thickness after drying would be 5 μm, and dried at 100° C. for 5 minutes to obtain a composite sheet. Table 1 shows the results of characteristic tests performed using the composite sheets obtained in Examples 1 to 4 and forming a surface protective layer.

[Table] Test method in Table 1 Initial adhesion strength: Cut the composite sheet into 25 mm width, BA
After pasting it on a finished stainless steel plate SUS304 and leaving it for 30 minutes, it was peeled off 180 degrees and the adhesive strength was measured.
Conditions (peeling speed 300mm/min, 20℃ x 65%
RH) Self-supporting sheet peeling force: After pasting the composite sheet on a BA-finished stainless steel plate SUS304, the self-supporting sheet was irradiated with ultraviolet light for about 5 seconds from a distance of 10cm using a high-pressure mercury lamp (80W/cm/1 lamp). Peel force was measured. Conditions (peeling speed 300mm/min, 20℃
×65%RH) Pencil hardness: The hardness of the polymerized cured product (surface protective layer) was measured according to JIS K5400. Adhesion: Make 100 cuts at 1 mm intervals in a grid pattern on the polymerized cured product (surface protective layer), paste commercially available cellophane adhesive tape on this, then peel off the tape and indicate the percentage of remaining base pieces. did. As is clear from the above examples, the method of the present invention is notable for the fact that a good surface protective layer can be easily formed on an adherend.

Claims (1)

[Claims] 1. A photocurable adhesive layer containing a photopolymerizable compound having at least one (meth)acryloyl group in the molecule, a photosensitizer, and a base polymer on the self-supporting sheet (or film) surface. The formed composite sheet (or film) is laminated onto the surface of an adherend via the adhesive layer, the adhesive layer is cured by backlight irradiation, and then only the self-supporting sheet (or film) is bonded. A method for forming a surface protective layer, which comprises peeling off to form a surface protective layer made of a polymerized cured product on the surface of the adherend.