JPS5996917A - Forming method of surface protection layer - Google Patents

Abstract

PURPOSE:To easily form a surface protection film on a member to be coated by a method wherein a composite sheet comprising a substrate having a radiation-setting adhesive layer applied thereon is adhered on the coated member, radiation is projected to harden the adhesive layer and then only the substrate is separated for removal. CONSTITUTION:A composition consisting of (A) a radiation sensitive compound having a vinyl group [e.g., (meth)acrylic acid alkylester] and (B) a radiation sensitive base polymer (e.g., acryl copolymer, rubber adhesive material) in ratio of about 80:20-10:90wt% is coated on a substrate (self-supporting sheet) (e.g., vinyl chloride sheet) to form a composite sheet which comprises a substrate having a radiation-setting adhesive layer applied thereon. Next, the composite sheet is adhered on a member to be coated (such as a metal or plastic plate) through the adhesive layer, and radiation is projected to cause the adhesive layer to be hardened through polymerization. Thereafter, the substrate is separated for removal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of 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, 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, the present invention 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 that semi-permanently prevents damage to the surface of an adherend.

Conventionally, the surface protection of adherends such as plate-shaped articles has been carried out by temporarily attaching a surface protection adhesive film before processing, and then applying paint etc. after processing. is common.

These series of steps begin with the attachment of the film to a plate-shaped article, followed by processing such as bending, drawing, and punching, followed by film peeling, surface cleaning, painting, and drying. Cleaning solutions and paints are complicated and contain a large amount of organic solvents, which poses various safety and hygiene problems.

Therefore, 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-like article before processing and 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 radiation-curable adhesive layer containing a radiation-sensitive compound having at least one vinyl group in the molecule and a radiation-sensitive base polymer or oligomer on the surface of a self-supporting sheet (or film). The formed composite sheet (or film) is laminated onto the surface of an adherend via the adhesive layer, and then radiation is irradiated to cure the adhesive layer, and then only the self-supporting sheet (or film) is bonded. This is achieved by peeling off 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 the broken adherend made of plate-shaped articles before and during processing is prevented by pasting the composite sheet, and after processing, it is irradiated with radiation to cure it. Since it is protected by a surface protective layer formed by polymerizing and curing a sticky adhesive layer, the surface of the broken adherend is not damaged.

At least one in the molecule used in the practice of the present invention
A radiation-sensitive compound having 1 vinyl group is a (meth)acrylic acid alkyl ester (carbonyl group number 1
5 or less) coon, cN, o in the side chain alone or together with this
ocR (R is an alkyl group), (:! ON Blends with vinyl monomers having polar groups selected from the group of Ht and their derivatives, or 1,4-butylene glycol di(meth)acrynote , 1,6-hexane gelicoldi(meth)acrylate, neopentyl glycol di(
meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)
Acrylate, tetramethylolmethanetetra (meth)
Monomers such as acrylates or epoxy acrylates,
Examples include oligomers such as urethane-modified acrylates and oligoester acrylates, and two or more of these may be used in combination as necessary.

Radiation-sensitive base polymers are divided into those that have adhesive properties themselves and those that exhibit the necessary adhesive properties by incorporating the radiation-sensitive compounds. The number of C in the group is 3 to 12
(meth)acrylic acid alkyl ester polymer, (meth)acrylic acid alkyl ester and (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, dimethylamine ethyl (meth)acrylate, styrene, vinyl acetate, (meth)acrylate ) A binary or ternary copolymer obtained by copolymerizing unsaturated compounds such as acrylonitrile, acrylamide, and their derivatives using a polymerization method such as solution, bulk, pearl emulsion, or suspension (using a crosslinking agent) or natural rubber, polyisoprene rubber, styrene-isoglene-styrene block copolymer rubber, styrene-butadiene rubber, nitrile-butadiene rubber, polyisobutylene rubber, ethylene-propylene rubber, etc. Examples include rubber-based adhesive substances mainly composed of rubber, and examples of the latter include saturated or unsaturated polyester resins, polybutyral resins, and the like.

In addition, examples of radiation-sensitive oligomers include those obtained by reacting the above-mentioned (meth)acrylic acid alkyl ester with a chain transfer agent (including those reacted with a vinyl monomer having a polar group), polyester acrylate, epoxy acrylate, etc. Examples include ester acrylates.

The mixing ratio of the radiation sensitive compound and the radiation sensitive base polymer or oligomer is 80:20 to 10:
90 is preferably 70:30 to 30:70 (each ratio by weight); if the content of the compound exceeds 80%, the cohesiveness of the radiation-curable adhesive layer before radiation irradiation will be poor, and the adhesive will ooze out to the side surfaces. etc. occur, and if it is less than 10%, sufficient curing cannot be obtained, making it undesirable. The cured adhesive composition is a radiation-transparent self-supporting sheet (or film), such as a polyvinyl chloride sheet or film, a polyolefin sheet or film (a sheet or film made of ethylene-vinyl acetate copolymer and its saponified product). f including b), po! On one side of J ester sheet or film (thickness is preferably 10 to 300μ2n), □A thickness of about 1 to 100μ
It is coated or transferred in a range of 2n to form a radiation-curable adhesive layer, but appropriate amounts of other compounding agents may be added to the composition depending on the purpose.

Examples of compounding agents include pigments such as zinc white, yellow lead, and red iron for the purpose of coloring or decoration, dyes such as toluidine red, phthalocyanine blue, and phthalocyanine green, other metal powders, glass beads, glass powder, and glass. Examples include flakes, etc., and adhesion-imparting resins such as ky7lene resin and coumaron resin for the purpose of improving adhesive strength to the surface of the adherend.

A composite sheet (or film) consisting of a self-supporting sheet (or film) and a radiation-curable adhesive layer configured in this way can be used as a board made of a metal plate, glass plate, wood board, decorative board, glass board, etc. It is attached to the surface of an adherend such as a shaped article via an adhesive layer. Therefore, in general, from a self-supporting sheet (or film), radiation sources such as α rays, β rays, γ rays, χ rays, neutron beams, and sulfur rays are used to remove 0. I
The adhesive layer is irradiated with radiation at an amount of at least Mra, preferably at least 2 Mro-d, to polymerize the adhesive layer. Then, by peeling off only the support sheet (or film), 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 during peeling, so the adhesive strength of the sheet (or film) is largely due to the plastic flow of the adhesive layer at the time of peeling. This can easily be done from the lost adhesive layer.

It will be understood that the timing of radiation irradiation (4) may be after the covering sheet has been attached to the adherend, such as a plate-shaped article, or before or after processing the adherend, such as sheet metal cutting, etc. .

As described above, according to the method of the present invention, by irradiating the composite sheet used to protect the surface of the adherend and peeling off the self-supporting sort, a surface protective layer that can protect the surface semi-permanently can be formed. It has the characteristic that it can be formed.

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.

Examples of the present invention are shown below, with 0 in the middle meaning parts by weight. Example 1 n-octyl acrylate 60 parts Methyl methacrylate 40 Methacrylic acid 3 Ethyl acetate
100 The above blended composition was polymerized by a conventional method to obtain an acrylic copolymer.

Next, 50 parts of tetraethylene glycol dimethacrylate and a reaction product of 3 moles of tolylene diisocyanate and 1 mole of 1,1,1-trimethylolpropane were added to 50 parts of the copolymer (solid content). Mix uniformly, apply to one side of a 100 μm thick polyethylene sheet to a dry thickness of 5 μm, and heat at 100°C for 5 μm.
After drying for a minute, a C composite sheet was obtained.

Example 2 Vinyl acetate 60 parts Methyl methacrylate 20 Propyl acrylic V-)2'O // Azobisisobutyronitrile 0.05 // Ethyl acetate 100 The above blended composition was polymerized by a conventional method to obtain an acrylic copolymer. A polymer was obtained.

Next, 30 parts of tetramethylolmethanetetraacrylate was added to 70 parts of the copolymer (solid content), mixed uniformly, and after drying was applied to one side of a 120 μm thick polyvinyl chloride sheet. The thickness is 5 μm.

The composite sheet was coated and dried at 100° C. for 5 minutes to obtain a composite sheet.

Example 3 Styrene-isofrene-styrene bronok-1ut composite rubber (manufactured by Shell Chemical Co., Ltd., trade name: Kraton 1107)
60 parts acrylated butadiene oligomer at both ends (manufactured by Idemitsu Petrochemical Co., Ltd., trade name PolyBD-R4,5ACR-LC) 40 The above blended composition was dissolved in toluene to create a 30% toene solution, and this was Coat the surface of a polyethylene sheet with a thickness of 100 μm so that the thickness after drying is 5 μm,
A composite notebook 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-15
07) 60 tt The above blended composition was dissolved in toluene to create a 30% toluene solution, and this was applied to a polyvinyl chloride sheet with a thickness of 1201t77J so that the thickness after drying was 5 μm. A composite sheet was obtained by drying for a minute.

Example 5 n-Butyl acrylate 35 parts Acrylonitrile 55 Hydroxyethyl acrylate 1 o β-mercaptoethanol 0.1 Azobis (cyanovaleric acid)
0.05 parts of the above formulation was placed in a reaction flask and reacted at 75°C for 4.5 hours to obtain a viscous oligomer.

Next, 40 parts of tetraethylene glycol dimethacrylate was blended with 60 parts of this oligomer, mixed uniformly, and 5μ
A composite sheet was obtained by forming the composite sheet to a thickness of m.

Table 1 shows the results of characteristic tests performed using the composite sheets obtained in Examples 1 to 5 and forming a surface protective layer.

Test method in Table 1 The initially bonded crab composite sheet was cut into a width of 25mm, pasted on a BA finished stainless steel plate 5US304, left for 30 minutes, and then peeled off at 180 degrees to measure the adhesive strength. Conditions (peeling speed 3 Q Q my/min, 20°C x 65%
R, H,) BA self-supporting sheet peelable crab composite sheet
After pasting it on a finished stainless steel plate 8US304, it was heated to 2 MeV and 3 m using an insulated iron core transformer type electron accelerator.
After irradiating the electron beam with the conveyor speed adjusted so that the irradiation dose was 5 Mrad under the conditions of A, the peeling force of the self-supporting sheet was measured. Conditions (peeling speed 300 my/
min, 20°C x 65% R, H,) Pencil hardness:
The hardness of the polymerized cured product (surface protective layer) was measured according to J.K. SK 5400.

Make 100 cuts at 1f1 intervals in the shape of a base grid on the adhesive crab polymerized cured product (surface protective layer), paste commercially available cellophane adhesive tape on this, then peel off the tape and display the remaining chips on the base grids. 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.

patent applicant Nitto Electric Industry Co., Ltd. Representative Sanbe Hijikata

Claims (1)

[Claims] A radiation-sensitive compound having at least one vinyl group in the molecule on the self-supporting sheet (or film) surface;
A composite sheet (or film) formed with a radiation-curable adhesive layer containing a radiation-sensitive base polymer or oligomer is laminated onto an adherend surface via the adhesive layer, and then irradiated with radiation to form the adhesive layer. A method for forming a surface protective layer, comprising: curing the self-supporting sheet (or film), and then peeling off only the self-supporting sheet (or film) to form a surface protective layer made of a cured polymer on the surface of the adherend.