JPH0158201B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive resin composition suitable for forming a sandblasting resist used when forming patterns on the surface of a substrate by sandblasting. Conventionally, as a method of creating a pattern on the surface of a substrate by sandblasting, a method is known in which paper, rubber, or the like is pasted on the substrate, cut out with a cutter knife, etc., and then sandblasted using this as a sandblasting resist (protective film).

However, in these methods, the protective film is usually created manually, and if the pattern is complex and thin, forming the protective film requires a lot of time and effort.

In recent years, in order to solve these problems, a method has been developed in which a protective film is formed on a substrate by a photographic method using a photosensitive resin and then sandblasted.
35681), or a method of forming a protective film by screen printing and sandblasting. In the former method, resin is applied directly onto the substrate, exposed through a patterned film, and the unexposed areas of the resin must be dissolved and removed, which is time-consuming and very tedious when patterning a large substrate. It is. In addition, in the latter method, the ink used is either a solvent-drying type or a two-component mixture that cures through a reaction, which often causes screen clogging and makes it difficult to create a complete design with sufficient thickness. It had some drawbacks. It was also difficult to peel off the protective film.

The present inventors have previously proposed a new method in which a photosensitive resin is made into ink and a pattern is formed on a base material by screen printing to form a protective film for sandblasting.
This method has made it very easy to form a protective film and has enabled mass production without clogging the screen, but there are problems in that it is difficult to remove the protective film after sandblasting, or it takes a long time to remove it. It had

In order to improve this point, the present inventors have intensively studied many resin compositions, and as a result, they form a protective film that adheres well to the substrate during sandblasting and can be easily peeled off from the substrate after sandblasting. We have discovered a photosensitive resin composition. That is, a photosensitive material for sandblasting resist containing as essential components an unsaturated polyester obtained from ethylene glycol or its condensate, maleic anhydride and phthalic acid, 2-hydroxyethyl methacrylate, polyvinylpyrrolidone or polyethylene glycol dimethacrylate, and a photopolymerization initiator. The present invention provides a synthetic resin composition.

In the present invention, the base material refers to a molded article made of glass, metal, polymethyl methacrylate, polystyrene, polyvinyl chloride, synthetic resin such as phenolic resin, urea-formalin resin, melamine resin, stone, leather, or wood. It also includes those having a paint layer made of alkyd resin, urethane resin, epoxy resin, etc., or a metal thin film layer made of silver, copper, aluminum, etc. on the surface of these substrates.

The photosensitive resin composition of the present invention is preferably a liquid product that can be screen printed. It may be made into a liquid by mixing a diluent such as a solvent. Furthermore, after screen printing, the photosensitive resin composition of the present invention is cured by irradiation with actinic rays to form a protective film that adheres closely to the substrate and is resistant to sandblasting. As a light source for this active light, an ultraviolet fluorescent lamp, a mercury lamp, a carbon arc lamp, sunlight, etc. are used. Although irradiation can be performed in air, it is preferable to irradiate in an atmosphere of an inert gas, such as nitrogen, argon, or carbon dioxide, in order to eliminate surface tackiness and to cure as quickly as possible.

As the unsaturated polyester, an unsaturated polyester obtained from ethylene glycol or its condensate, maleic anhydride and phthalic acid is used. Furthermore, after irradiation with actinic light and blasting, a combination of 2-hydroxyethyl methacrylate and polyvinylpyrrolidone or polyethylene glycol dimethacrylate is added to the unsaturated polyester to facilitate peeling from the substrate by immersion in water. do. The amount of this compound added is 3% by weight or more, preferably 5% by weight or more in order to facilitate peeling by immersion in water after blasting. On the other hand, the content is desirably 90% by weight or less in order to have adhesion to the base material and strength to withstand sandblasting. Examples of photopolymerization initiators include benzoin, benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether, anthraquinones such as anthraquinone and 2-methylanthraquinone, benzophenone, benzyl, diphenyl disulfide, diacetyl, etc. A conventionally known one is used.

The amount of photopolymerization initiator added is 100% of the compound used that has one or more ethylenically unsaturated bonds in the molecule.
Add 0.5 part to 10 parts by weight. Also,
Hydroquinone, hydroquinone monomethyl ether, 2,6-di-
Add 0.05 part to 1.0 part per 100 parts by weight of a compound containing one or more ethylenically unsaturated bonds in the molecule, such as t-butyl-p-cresol.

Furthermore, various viscosity modifiers such as solid fine powders such as silicon dioxide and magnesium oxide, various polymers, thickeners, solvents, etc. may be added to improve screen printability.

Furthermore, a coloring agent such as a dye or a pigment can be added to make the protective film easier to see.

The composition of the present invention has good adhesion to substrates and is flexible, so it is particularly excellent as a sandblasting resist.

Various methods can be used to form a pattern on a substrate using the composition of the present invention. For example, a method of directly printing on a substrate and curing by irradiating with actinic rays, or a method of printing on release paper or a release film, curing and pasting on the substrate, etc. are used.

In order to use the resin composition of the present invention in the pasting method, the resin cured by irradiation with actinic rays must have flexibility. For this purpose, an appropriate proportion may be selected from the above-mentioned composition, but a composition containing 30% by weight or more of the above-mentioned unsaturated polyester is preferred.
Generally, after sandblasting, the cured resin formed on the substrate is peeled off from the substrate. The method of peeling is to immerse it in water so that it will peel off naturally from the base material. If the water temperature is raised, peeling becomes easier. The length of time for immersion in water varies depending on the type of resin and the material of the base material, but it is usually 10 minutes or more, preferably 20 minutes or more for complete peeling. Of course, even if the immersion time is around 1 minute, it can be easily peeled off with physical force.

By using the composition of the present invention, operations such as patterning and lettering on a base material have become extremely easy. In particular, it is excellent in that a protective film can be formed by screen printing and peeling can be easily performed by simply immersing it in water.

This improves the conventional method of removing a protective film from a base material, which took time or caused damage to the surface of the base material due to forceful peeling.

The composition of the present invention is also photosensitive and will not cure unless exposed to actinic light. Therefore, beautiful printing can be achieved for a long time without clogging the screen printing plate.

Using the composition of the present invention, patterns can be easily applied to molded products of various substrates, such as glass, metal, resin, etc.

EXAMPLES Next, the present invention will be specifically explained using Examples, but the present invention is not limited thereto.

Example 1 50 parts by weight of unsaturated polyester synthesized from triethylene glycol, maleic anhydride, and phthalic acid, 20 parts by weight of 2-hydroxyethyl methacrylate, polyethylene glycol dimethacrylate (NK-23G, manufactured by Shin Nakamura Chemical Industries) 20 parts by weight,
10 parts by weight of pentaerythritol triacrylate, 7 parts by weight of silica powder (manufactured by Nippon Aerosil Co., Ltd.), 1 part by weight of benzoin isobutyl ether,
Add 0.1 part by weight of 2,6-di-t-butylcresol (Sumilizer BHT, manufactured by Sumitomo Chemical) and 0.5 part by weight of Sumiplast Violet RR as a coloring agent, and knead well with a triple roll to make a photosensitive resin. A composition was prepared. This composition was screen printed on a glass plate through a thick stencil (film thickness 250 microns) having an arabesque cut-out pattern prepared separately, and immediately irradiated with ultraviolet fluorescent lamps (10 20W). Irradiation was performed for 1 minute at a distance of approximately 10 cm. An arabesque pattern of hardened resin was created on the glass plate. This was then injected with 200 mesh of alundum together with 2 kg/cm ² of compressed air.

After sandblasting the entire surface of the glass plate, the glass plate was immersed in water. After a while, the hardened resin swelled with water, expanded, and began to peel off from the glass plate. In this way, it has the advantage that the protective film can be peeled off at the same time as cleaning the glass plate soiled with sand. A transparent arabesque pattern appeared on the frosted glass plate.

Example 2 70 parts by weight of the same unsaturated polyester as in Example 1,
30 parts by weight of 2-hydroxyethyl methacrylate, 20 parts by weight of polyvinyl pyrrolidone, silica powder (Aerosil #300, manufactured by Nippon Aerosil Co., Ltd.) 8
parts by weight, 1 part by weight of benzoin isobutyl ether, 0.1 part by weight of 2,6-di-t-butyl cresol, and Sumiplastret as a coloring agent.
0.1 part by weight of AS was thoroughly mixed and kneaded uniformly using a three-roll mill. This composition was screen printed onto cylindrical tips (thickness: 200μ). Immediately after printing, the ink was cured by irradiation with an ultraviolet fluorescent lamp. Next, 200 mesh of Vajra sand was sprayed onto this material along with 1.5 kg/cm ² of compressed air. The photo-cured area withstood the blast and was sufficient as a protective film. After plastination, the hardened resin peeled off when the tip was immersed in water.

Example 3 The composition of Example 1 was screen printed onto an aluminum plate and spray-blasted with 80 mesh glass beads with 3 kg/cm ² of compressed air after being placed under an ultraviolet fluorescent lamp for 2 minutes. When the aluminum plate was then immersed in water, the photocured resin peeled off and a pattern appeared on the aluminum plate.

Claims (1)

[Claims] 1 Photosensitivity for sandblasting resist containing as essential components unsaturated polyester obtained from ethylene glycol or its condensate, maleic anhydride and phthalic acid, 2-hydroxyethyl methacrylate, polyvinylpyrrolidone or polyethylene glycol dimethacrylate, and a photopolymerization initiator Resin composition.