JPH0366946B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention utilizes a screen printing ink based on a rubber-like elastic material having ultraviolet curable property to screen print on an inorganic or organic surface on which a desired engraving is to be made, and then The present invention relates to a method for forming a sandblasting-resistant surface protective film which is cured by ultraviolet irradiation and has chemical resistance and removability. (Prior art) The conventional sandblasting method involves cutting a synthetic rubber sheet, vinyl chloride sheet, etc. with a thickness of about 1 to 3 m/m to match the size of the object to be engraved, and then carving predetermined characters, figures, patterns, etc. draw,
Paste it onto the surface to be engraved, cut out parts such as letters, figures, patterns, etc. with a knife, etc. to create a master plate for engraving, and engrave by blowing ultra-hard particles such as metal sand (hereinafter referred to as "sandblasting"). This method is completed by peeling and removing the synthetic rubber plate. A photosensitive resin plate with a thickness of about 1 to 3 m/m is cut to match the size of the object to be engraved, and is pasted on the surface to be engraved to form letters, figures, patterns, etc. A negative or positive photomask depicting the image is closely attached to a photosensitive resin plate, then cured with ultraviolet rays, the photomask is removed, the uncured areas are developed using a developing solution such as an organic solvent or aqueous alkaline solution, and heated. Create an original plate for engraving by drying using irradiation or infrared irradiation, paste it on the surface to be engraved,
The method is completed by sandblasting and peeling off the original plate for engraving. Apply photosensitive resin liquid to the surface to be engraved, cover with polyester film, adjust the thickness to about 1 to 3 m/m, and adhere a photomask on top of it. Then, the photomask and polyester film are removed, the uncured areas are developed using a developer such as an organic solvent or an aqueous alkaline solution, and then dried using heat or infrared irradiation. A method of creating an engraving original plate, pasting it on the surface to be engraved, sandblasting, and peeling off the original engraving plate to complete the process.Screen printing on the engraving surface using an organic solvent-based screen printing ink and evaporating it at room temperature. A method of sandblasting a surface protective film dried by drying, heat drying or drying using infrared irradiation, and completing the process by peeling off the surface protective film. There are known methods such as screen printing on an engraved surface and drying the surface protective film by drying by evaporation drying, heating drying, or infrared irradiation at room temperature, sandblasting, and completing the process by peeling off and removing the surface protective film. It is being (Problems to be Solved by the Invention) However, these conventional methods have had many problems. First, in the conventional method of using a synthetic rubber plate as a master plate for engraving, it is necessary to cut the rubber plate to match the size of the object to be engraved, or to cut out letters, figures, patterns, etc. with a knife, etc. If the surface to be carved is hard, the cutting edge may become chipped or worn, requiring the cutting tool to be replaced with a new one or resharpened. Furthermore, if the surface to be engraved is soft, this is not preferable because it may damage the surface to be engraved.
Furthermore, since characters, figures, patterns, etc. must be drawn on each sheet, it is very time-consuming. Also, letters,
Since figures, patterns, etc. must be cut out by hand, it is not possible to create a precise master plate for engraving. The synthetic rubber that is cut out and removed is wasted and must be disposed of. These drawbacks, coupled with the fact that the work was done on-site, increased the number of man-hours and costs. In the conventional method of creating an original plate for engraving using a photosensitive resin plate, the photosensitive resin plate is cut to match the size of the object to be engraved and pasted, as in the conventional method. It took a lot of time. Further, the photosensitive resin plate needs to be developed after being irradiated with ultraviolet rays. The development process uses a developer such as an organic solvent or an alkaline aqueous solution, which is difficult to work with, is harmful to the human body, and requires the installation of a draft or a dedicated developing machine. Furthermore, the developer used for development, such as an organic solvent or an alkaline aqueous solution, must be replaced when used for a long period of time, and requires disposal. In addition, when using a photomask with characters, figures, patterns, etc. on it that leaves a large amount of uncured parts after exposure, the amount of photosensitive resin that must be developed is naturally large, making it unnecessary to take the time and effort to reuse it. This resulted in a lot of waste and high costs. Furthermore, after the development process, it was necessary to perform a drying process using heating or infrared irradiation, which was time-consuming. Similarly to the conventional method, the method of creating an original plate for engraving using a photosensitive resin liquid includes the following steps:
There were many common problems. That is, after irradiation with ultraviolet rays, it is necessary to perform a development process, and the development process uses a developer such as an organic solvent or an alkaline aqueous solution, which has poor workability and is harmful to the human body.
It was necessary to install a draft and a special developing machine.
Furthermore, the developing solution such as an organic solvent or aqueous alkaline solution used for development must be replaced when used for a long period of time, requiring disposal. Also, after exposure,
Characters, figures, etc. that have many uncured parts left behind
When using a photomask with a pattern or the like drawn on it, the amount of photosensitive resin that must be developed is naturally large, and the process of reusing the photosensitive resin requires a lot of effort, resulting in a lot of waste and high costs. Further, after the development process, it was necessary to perform a drying process by heating or infrared irradiation, which was time-consuming. For this reason, instead of developing using a developer such as an organic solvent or aqueous alkaline solution, a method has been proposed in which the uncured photosensitive resin liquid is blown off with an air knife; It is not possible to completely remove the photosensitive resin liquid, which causes defects to remain on the sandblasted surface. The conventional method using organic solvent-based screen printing ink can eliminate the labor and waste of the conventional method by screen printing, but since it uses an organic solvent, it has poor workability and is harmful to the human body. It was harmful and required environmental equipment such as a draft. Furthermore, since the organic solvent evaporates to a greater or lesser extent, the viscosity of the ink changes, making it necessary to adjust the viscosity before use, and also causing clogging of the screen plate. Also, depending on the type of solvent used, the screen plate may be immersed in the emulsion, thereby shortening the life of the screen plate. When a high boiling point solvent is used, this problem is reduced, but drying becomes more difficult.
Both high boiling point solvents and low boiling point solvents can be evaporated and dried at room temperature.
It was necessary to perform a drying process such as heating drying or drying by infrared irradiation, which took time. Furthermore, since it contains evaporative components, the film thickness changes immediately after printing and after drying, making it difficult to control the thickness, and only a thin dry film can be formed. As a result, the sandblasting resistance deteriorated, making it impossible to form a surface protective film suitable for sandblasting. The conventional method of using a water-dispersed screen printing ink has alleviated the pollution drawbacks of the conventional method, but there are changes in the viscosity of the ink, the need to adjust the viscosity, and problems with the screen printing plate. Defects such as clogging remain. Further, it was necessary to perform drying treatment by evaporation drying at room temperature, heating drying, or infrared irradiation, which took time. In addition, since it contains evaporative components, the film thickness changes immediately after printing and after drying, making it difficult to control the thickness, and only a thin dry film can be formed, which reduces sandblasting resistance.
This method had problems such as not being able to form a surface protective film suitable for sandblasting. (Means for Solving the Problems) Therefore, the present inventors conducted long-term sincere research in order to overcome the drawbacks of the conventional method, and as a result, they arrived at the present invention. The present invention relates to a method for forming a sandblast-resistant surface protective film that overcomes many of the drawbacks of the conventional methods. That is, the method for forming a sandblast-resistant surface protective film of the present invention utilizes a screen printing ink based on a rubber-like elastic material having ultraviolet ray curability to coat an inorganic surface or an organic surface on which a desired engraving is to be performed. Screen printed on top, then dried by UV irradiation,
This is a method of forming a sandblasting resistant surface protective film. According to the present invention, it is possible to improve the safety and workability of the conventional method, eliminate waste, and significantly reduce the number of steps and costs. What's more, screen printing accurately reproduces minute characters, figures, patterns, etc.
To provide a sandblasting method that can sufficiently withstand sandblasting even with a thickness of 30 μm and is easy to re-peel. The present invention will be explained below based on the configuration. The rubber-based copolymer having ultraviolet curable properties as a rubber-like elastic body having ultraviolet curable properties used in the present invention includes 100 parts by weight of a liquid rubber having a hydroxyl group with a molecular weight of 1,000 to 10,000, and 5 to 190 parts by weight of a diisocyanate compound. , a rubber-based copolymer with ultraviolet curable properties made by uniformly mixing and reacting 1 to 90 parts by weight of a dihydric alcohol with a molecular weight of 300 or less and 2 to 25 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group. , its main components are as follows; (However, R is an alkyl group having 1 to 8 carbon atoms, R ₁
is H or CH ₃ , R ₂ is a diisocyanate residue, R ₃
is the residue of dihydric alcohol with the hydroxyl group removed, X is the part of the diene liquid rubber having the hydroxyl group with the hydroxyl group removed, l is 1 to 4, n is 1 to 12, m is 1<m<3
). Examples of the diene-based liquid rubber having a hydroxyl group include number-average 1,2-polybutadiene, 1,4-polybutadiene, 1,2-pentadiene, styrene-butadiene copolymer, acrylonitrile-polybutadiene copolymer, isoprene, etc., which have a hydroxyl group in the molecule. It is a polymer with a molecular weight of about 1000 to 10000, the position of the hydroxyl group is arbitrary, and the number of hydroxyl groups in the molecule (m) is about 1<m<3. Examples of the ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate.
Examples include hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and polypropylene glycol monomethacrylate. Examples of diisocyanate compounds include tolylene diisocyanate, xylylene diisocyanate,
naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
Examples include 4,4'-diphenylmethane diisocyanate, lysine diisocyanate, and hydrogenated tolylene diisocyanate. Examples of dihydric alcohols with a molecular weight of 300 or less include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,3-propylene glycol.
Butanediol, 1,4-butanediol, 1,
5-pentanediol, 1,6-hexanediol, trimethylolpropane monoacrylate,
Examples include trimethylolpropane monomethacrylate and glycerol-α-monoallyl ether. Next, compositional limitations of the ultraviolet curable rubber-like elastic body used in the present invention will be explained. The above diisocyanate compound and dihydric alcohol with a molecular weight of 300 or less are 5 to 190 parts by weight and 1 to 190 parts by weight, respectively, per 100 parts by weight of diene liquid rubber having a hydroxyl group.
90 parts by weight is preferable, and when the total amount of the two components exceeds 280 parts by weight per 100 parts by weight of liquid rubber having a hydroxyl group with a molecular weight of 1,000 to 10,000, the properties of the rubber (chemical resistance, water resistance, flexibility, elasticity,
This is undesirable because the elongation (elongation, restorability against bending) and adhesion to the base material are lowered, and the resistance to sandblasting is lowered. In addition, if the total amount of the two components does not reach 6 parts by weight per 100 parts by weight of the liquid rubber, the microscopic phase separation between the hard segment and the soft segment will not occur properly, resulting in high strength and high elongation. Since it becomes difficult to obtain a photocured product, the cured film is damaged by sandblasting, which is not preferable. In other words, for sandblasting, the protective film needs to have the above-mentioned rubber properties and physical properties of appropriate strength, so such compositional limitations are imposed. Here, the portion n of continuous urethane bonds in formula () represents a hard segment, and the portion X in formula () represents a soft segment and corresponds to the rubber main chain. Formula () consists of these two segments, and the softness and physical properties of the polymer, such as flexibility and bending resistance, appear from the soft segment,
Hard physical properties such as strength, toughness, and tear strength appear from the hard segments. Therefore, if only soft segments are used, the protective film may be damaged during sandblasting, but if hard segments are incorporated, the protective film will have the properties of rubber and appropriate strength, and it will be more durable during sandblasting. It has the effect of having excellent physical properties such as moderate adhesion and releasability after treatment. The ethylenically unsaturated monomer having a hydroxyl group is preferably used in an amount of 2 to 25 parts by weight per 100 parts by weight of diene liquid rubber having a hydroxyl group. ) or a polymer different from the main component formula () is generated.
The generation of unreacted components causes problems such as reduced yield and poor storage stability, and the formation of a polymer having a structure different from formula () is unfavorable in terms of physical properties. Only the ethylenically unsaturated monomer contained therein contributes to the addition polymerization, and the remainder remains as an unreacted material, which is not preferable. Furthermore, even if the amount does not reach 2 parts by weight, unreacted components (all blended components) will be generated during the polymerization step, or a polymer different from the main component formula () will be generated, and the generation of unreacted components will reduce the yield. This may cause problems such as reducing storage stability and reducing storage stability.
The production of a polymer having a structure different from the formula () is unfavorable in terms of physical properties, and there arises a problem of poor photosensitivity upon addition polymerization. As described above, polymerization is limited by the molecular weight and number of reactive groups of each component, and the amount of the main component is limited by formula ().

[Table] The rubber-like elastic body having ultraviolet curable properties suitable for use in the present invention includes 100 parts by weight of a liquid rubber having a hydroxyl group with a molecular weight of 1,000 to 10,000, 5 to 190 parts by weight of a diisocyanate compound, and a dihydric alcohol with a molecular weight of 300 or less. A rubber copolymer with ultraviolet curability, which is made by uniformly mixing and reacting 1 to 90 parts by weight and 2 to 25 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group, and its main component is expressed by the formula (). The rubber-based urethane acrylate shown has flexible physical properties after UV curing, and its approximate pencil hardness value is B ~
6B polyether urethane acrylate,
Alternatively, it is selected from polyester urethane acrylate. Examples of polyether urethane acrylates include modifying the ends of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. with a diisocyanate compound such as 2,4-tolylene diisocyanate, that is, modifying both ends with NCO groups ( isocyanate group) and an ethylenically unsaturated monomer having one hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, etc. in a ratio of 1:2. There is a reacted polyether urethane acrylate,
Examples of polyester urethane acrylates include polyesters made of ethylene glycol and adipic acid, polyesters made of 1,6-hexanediol and adipic acid, polyesters made of ethylene glycol, adipic acid, and triethylene glycol, etc. , a prepolymer modified with a diisocyanate compound such as 4-tolylene diisocyanate, that is, with NCO groups at both ends, and an ethylenically unsaturated monomer having one hydroxyl group as described above, :=
There is a polyester urethane acrylate reacted at a ratio of 1:2. For example, as a polyether urethane acrylate, Aronix M-
1100, Aronix M-1200 (manufactured by Toagosei Kagaku Kogyo Co., Ltd., product name), Goselac UV2000B, Goselac UV3000B (all manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.)
Polyester urethane acrylates include PU-122 and PU-124 (trade names, manufactured by Arakawa Chemical Industries, Ltd.). Here, the fact that the physical properties of the coating film after UV curing are flexible, with a pencil hardness of B to 6B means that benzoin, benzoin methyl ether, benzoin, benzoin methyl ether, Add a photosensitizer such as benzophenone, Michler's ketone, azobisisobutyronitrile, benzyl dimethyl ketal, 2-methylanthraquinone, 2,2-diethoxyacetophenone, etc., until the acryloyl group (or methacrylate group) reacts sufficiently. When irradiated with ultraviolet rays, the physical properties of the cured film have a pencil hardness of B to 6B, which means that it is rubber-like. A solvent-free or solvent-free screen ink having screen printing properties suitable for use in the present invention is based on the above-mentioned ultraviolet curable rubber-like elastic material, an ethylenically unsaturated monomer, a photosensitizer, Thermal polymerization inhibitor, coloring agent,
This is an ink composition prepared to impart screen printing properties by adding and blending an antifoaming agent, a thickener, a release agent, a general-purpose rubber, a liquid rubber, a small amount of an organic solvent, etc. as necessary. Examples of the ethylenically unsaturated monomer include the aforementioned ethylenically unsaturated monomers having a hydroxyl group, methyl methacrylate, ethyl methacrylate, butyl methacrylate, glycidyl methacrylate, 1,4
- Methacrylates such as butylene dimethacrylate, ethylene glycol dimethacrylate, diethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1, Acrylates such as 6-hexane diacrylate and diethylaminoethyl acrylate, methacrylic acid, acrylic acid, acrylonitrile, acrylamide, N-methylolacrylamide, styrene, vinyltoluene, α-methylstyrene, vinyl acetate, N-vinyl-2-pyrrolidone, diallyl phthalate, etc., and its blending amount is determined by the above-mentioned ultraviolet curable rubber-like elastic material.
One or more of them is used in a normally used amount of 10 to 200 parts by weight per 100 parts by weight. Examples of photosensitizers include benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, benzophenone, Michler's ketone, 1-naphthalenesulfonyl chloride, 2,5-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, azoisobutyronitrile. , 1-azobis-1
-Cyclohexanecarbonitrile, benzyl dimethyl ketal, 2-methylanthraquinone, biimidazole, thioxanthone, 2,4-diisopropylthioxanthone, 2,2-diethoxyacetophenone, benzoin peroxide, 2,4
-Dichlorobenzoyl peroxide, etc., and the amount of one or more of them is used in the usual amount of 0.1 to 10 parts by weight per 100 parts by weight of the above-mentioned ultraviolet curable rubber-like elastic body. As the thermal polymerization inhibitor, hydroquinone, t-
Butylcatechol, o-dinitrobenzene, o-
Nitrophenol, m-nitrophenol, p-
Nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, phenothiazine, ferric chloride, etc. are included, and their blending amounts are as follows:
One or more of them is used in a normally used amount of 0.01 to 1.0 parts by weight per 100 parts by weight of the above-mentioned ultraviolet curable rubber-like elastic body. The coloring agent may be a dye or a pigment, and the amount of the colorant to be added is the amount usually used for 100 parts by weight of the rubber-like elastic material having ultraviolet curable properties as described above.
It is used in an amount of 0.001 to 10 parts by weight. Antifoaming agents include silicone-based, acrylic-based, polyglycol-based, and polyether-based surfactants, and the blending amount is one or two based on 100 parts by weight of the above-mentioned ultraviolet-curable rubber-like elastic material. The seeds or more are used in commonly used amounts, from 0.1 to 10 parts by weight. Examples of thickeners include inorganic fillers such as silicas, talcs, magnesium carbonate, calcium carbonate, and titanium oxide.
One or more of them are used in a commonly used amount of 0.5 to 200 parts by weight. Examples of release agents include silicone-based, glycol-based, acrylic-based, and wax-based release agents. Two or more types are used in a normally used amount of 0.1 to 10 parts by weight. General-purpose rubbers include polybutadiene, isoprene, chlorosulfonated polyethylene, natural rubber,
There are general-purpose rubbers such as polybutylene, and the amount of one or more of them is usually used per 100 parts by weight of an ultraviolet-curable rubber-like elastic material, 5 to 20 parts by weight.
Used in parts by weight. The rubber may be added under particularly severe conditions in order to improve the chemical resistance and heat resistance of the ink. The amount of compounding depends on the effect on the UV curing properties and the properties of the screen ink, and if it is added in excess of the above amount, the rubber is a non-photosensitive substance, so the UV curability will decrease, and furthermore, it will not be suitable for general purpose organic solvents. Since rubber is added to the ink as a solution containing dissolved rubber, it is unfavorable from the standpoint of pollution and workability. Liquid rubbers include liquid types of the general-purpose rubbers mentioned above, and the amount of one or more of them is usually used per 100 parts by weight of an ultraviolet-curable rubber-like elastic material, from 5 to 50 parts by weight. Used in parts by weight. As with general-purpose rubber, it may be added under particularly severe conditions to improve resistance, giving a cured product with improved rubber elasticity and chemical resistance. The amount of compounding depends on the effect on UV curability and screen ink characteristics, just like general-purpose rubber, and the effect when added in excess of the above-mentioned amount is also the same as general-purpose rubber, but since it does not contain organic solvents, No problems will arise regarding pollution, work characteristics, etc. In addition, when adding an organic solvent as a solution of general-purpose rubber dissolved in an organic solvent, it is added as necessary, such as when it is necessary to impart screen printing characteristics, and the type of organic solvent is arbitrary. The amount used is 5 to 20 parts by weight, which is the amount normally used for rubber-like elastic bodies having ultraviolet curable properties. This amount is an amount that does not interfere with screen printing characteristics, worsen the working environment, or cause clogging of the screen due to evaporation of the organic solvent, and furthermore, it is sufficient to prevent curing of the rubber-like elastic material having ultraviolet curable properties. This is an amount that does not have any adverse effects such as a decrease in speed or poor curing, and although the amount varies depending on the solubility of the solvent, it is a normally used amount. (Examples) The present invention will be described below based on Examples. Example 1 (Example of polymerized rubber copolymer with ultraviolet curable property) 29.2 g of 2,4-tolylene diisocyanate was dissolved in 87.6 g of dioxane, and the solution was placed in a 500 ml reactor under a nitrogen atmosphere. While stirring, add 1,4
- A solution of 7.5 g of butanediol dissolved in 22.5 g of dioxane was added via the dropping funnel. During dripping,
Keep the reaction temperature at 45-50℃, and after the completion of dropping, keep the reaction temperature at 45-50℃.
℃ for 3 hours. After that, 10g of 2-hydroxyethyl methacrylate, 0.15g of hydroquinone
g, triethylenediamine 0.075g is dioxane
A solution of 33 g was added via an addition funnel.
During the dropwise addition, the reaction solution was kept at 75 to 80°C, and after the dropwise addition was completed, the reaction was carried out at 75 to 80°C for 2 hours. moreover,
Poly bd R-45D (hydroxyl group-terminated polybutadiene liquid rubber, average molecular weight 2800, hydroxyl group content 0.83meg/
g, manufactured by Idemitsu Petrochemical Co., Ltd.) 100g and dioxane 300g
and put the solution into another 100 ml reactor,
The pre-reactants were added via addition funnel while stirring under a nitrogen atmosphere. During the dropwise addition, the reaction solution was maintained at 75 to 80°C, and after completion of the dropwise addition, the reaction was allowed to proceed at 75 to 80°C for 8 hours, and the reaction was completed when it was confirmed by an infrared absorption spectrum that the absorption of isocyanate groups had disappeared. While stirring the beaker containing 5400 ml of hexane, the reaction solution was gradually dropped into the beaker to obtain a white precipitate. The hexane-purified precipitate was dried in a vacuum dryer for 2 days to obtain a solid rubber-based urethane acrylate. The urethane acrylate was dissolved in tetrahydrofuran, and 5% of IRGAKURE 651 (manufactured by Ciba Geigy) was added as a sensitizer to prepare a photosensitive solution. The photosensitive solution was applied to a glass plate and tetrahydrofuran was evaporated to dryness. The thickness after drying was 100 μm. Next, an ultra-high pressure mercury lamp (input 3 kW, manufactured by Oak Seisakusho Co., Ltd.) was placed at a distance of 50 cm and exposed for 30 seconds to obtain a cured film. The physical properties of the cured film measured using a tensile tester were a tensile strength of 120 Kg/cm, an elongation of 250%, and a JIS hardness (Shor A) of 70. Example 2 (Example of solvent-free screen ink having screen printing properties based on a rubber-like elastic body having ultraviolet curable property) Based on the rubber-based urethane acrylate described in Example 1, ethylenically unsaturated monomer Ink A is added with additives such as , photosensitizer, etc., and ethylenically unsaturated monomer, photosensitizer, etc. are added based on commercially available polyether urethane acrylate "Aloex M-1100". Ink B was prepared by adding the agent. The formulation contents of inks A and B are shown in Table 2.

【table】

[Table] In the case of ink A, the rubber-based urethane acrylate described in Example 1 was mixed with N-vinyl-2-
Pyrrolidone and ethyl carbitol acrylate were stirred and dissolved, and after dissolution, all of the above additives were added to the solution and stirred again. Then, it was passed through an ink roll a total of three times to obtain Ink A. In the case of ink B, "Aronix M-1100" was dissolved with N-vinyl-2-pyrrolidone and ethyl carbitol acrylate with stirring, and after dissolution, all of the above additives were added to the solution and stirred again. Then, it was passed through an ink roll a total of three times to obtain Ink B. The viscosity and thixotropic index of Inks A and B are shown in Table 3. Viscosity and thixotropic index measurements were performed at 25°C using a BH type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

[Table] Example 3 (Screen printing) Screen printing was performed using inks A and B prepared in Example 2 above. The screen printing conditions were a screen mesh of 150 mesh, a screen emulsion thickness of 50 μm, a screen plate with a fine line resolution pattern, and a urethane squeegee with a hardness of 60 to perform manual screen printing on a glass plate. Ta. The results are shown in Table 4.

[Table] Measured using an outside micrometer manufactured by Mitoyo Seisakusho Co., Ltd. Example 4 (Curing by ultraviolet rays) Ink A printed on the glass plate of Example 3
and B were cured under the following curing conditions. Curing conditions: Ultra-high pressure mercury lamp "Polymer Printer" (input 3kW, manufactured by Oak Seisakusho Co., Ltd.)
using a distance of 50 cm between the glass plate and the lamp, and an exposure time of 30 seconds. After curing, both inks A and B were in a tack-free state, and there were no defects such as wrinkles in the ink due to uncuring. The pencil hardness of ink A was B, and the pencil hardness of ink B was 6B. Example 5 (Sandblasting, etching with hydrofluoric acid, etc., and re-peeling of the surface protective film) Printed on a glass plate in Example 4, and then hardened inks A and B were sandblasted under the following sandblasting conditions. . Sandblasting conditions: Sandblasting machine "TDH-401" (Tokyo Shibaura Electric Co., Ltd.), sandblasting material type "Alundum #150" (Nippon Carlits Co., Ltd.)
(manufactured by), nozzle diameter 15 mm, air pressure 4 kg/
cm ² , the distance between the glass plate and the nozzle was 10 cm, and the sandblasting time was 1 minute.
). After sandblasting, the surface protective films of glass plates A and B were not immersed in any way. Next, the sandblasted glass plates A and B were etched using a mixed solution of hydrofluoric acid and sulfuric acid under the following etching conditions. Etching conditions: 1 with hydrofluoric acid and sulfuric acid:
Approximately half of the mixed solution in Example 1 was poured into a polyethylene pad of 1 volume, and the sandblasted glass plates A and B were immersed therein. After soaking for 2 minutes, take the two glass plates outside, transfer them to a plastic bucket half-filled with water, and use a regular scrubber with your hands wearing rubber gloves to clean the front and back of the glass plates.
That is, it was washed with water by brushing both sides. By brushing, glass plate A
The surface protective film adhering to and B was completely peeled off. Next, the peeled glass plates A and B are
Glass plate A' and glass plate B' were obtained by washing with tap water and wiping off the water with a cloth.
A' is glass plate A that has been etched, and glass plate B' is glass plate B that has been etched.) For both glass plates A' and B', the parts covered by the surface protective film were transparent and without any scratches, and the parts not covered by the surface protective film were opaque.
It was carved with a depth of about 0.1mm. (Effects of the Invention) As explained above, the present invention uses a solventless or solvent-free screen ink, so the working environment is improved and air conditioning equipment etc. are not required. In addition, due to the screen printing method,
Precise sandblasting is possible, and since UV curing is used, a surface protective film can be formed in a few seconds to tens of seconds. Therefore, this is a method that can reduce the number of work hours and costs of the conventional method, and can greatly contribute to solving the problems of the conventional method. Furthermore, the surface protective film used in the present invention exhibits sufficient sandblasting resistance despite being a thin film with a cured thickness of 30 μm, and has excellent not only sandblasting resistance but also chemical resistance.
Utilizing this property, it is possible to perform chemical treatments such as etching with hydrofluoric acid or the like before or after sandblasting, and the treated surface protective film can be immersed in water and brushed. By rolling up the edge of the membrane by hand, the effect can be obtained that it can be easily peeled off.

Claims (1)

[Claims] 1. After performing the desired engraving by sandblasting using a surface protective film deposited on the inorganic or organic surface on which the desired engraving is to be performed,
In the sandblasting engraving method in which the surface protective film is peeled off and removed, the surface protective film is prepared into a solvent-less or solvent-free screen ink having screen printing properties, mainly based on a rubber-like elastic material having ultraviolet curable properties. A sandblasting-resistant surface protection characterized in that the ink is screen printed on an inorganic or organic surface on which a desired engraving is to be made, and then cured by irradiation with ultraviolet rays to form a surface protection film. Film formation method. 2. The rubber-like elastic body having ultraviolet curability is
100 parts by weight of liquid rubber having a hydroxyl group with a molecular weight of 1,000 to 10,000, diisocyanate compound 5 to 190 parts by weight
Part by weight, dihydric alcohol with a molecular weight of 300 or less 1 to 90
It is a rubber-based copolymer with ultraviolet curability, which is made by uniformly blending and polymerizing four components consisting of 2 to 25 parts by weight of ethylenically unsaturated monomers having a hydroxyl group, and its main components are: formula; (However, R is an alkyl group having 1 to 8 carbon atoms, R ₁ is H or CH ₃ , R ₂ is a diisocyanate residue, R ₃ is a residue of a dihydric alcohol excluding the hydroxyl group, and X is a diene system having a hydroxyl group. Formation of a sandblast-resistant surface protective film according to claim 1, which is a portion of liquid rubber excluding hydroxyl groups, where l is 1 to 4, n is 1 to 12, and m is 1<m<3. Method. 3. The rubber-like elastic body having ultraviolet curable properties is
The sandblasting-resistant surface protection according to claim 1, which is a polyether-based urethane acrylate or a polyester-based urethane acrylate that has flexible coating properties after being cured by ultraviolet rays and has a pencil hardness value of B to 6B. Film formation method. 4. The composition of the solvent-less or solvent-free screen ink having screen printing characteristics is a rubber-like elastic body having ultraviolet curable properties.
Based on 100 parts by weight, the main component is 10 to 200 parts by weight of ethylenically unsaturated monomer and 0.1 parts of photosensitizer.
~10 parts by weight, thermal polymerization inhibitor 0.01-10 parts by weight, colorant 0.001-10 parts by weight, antifoaming agent 0.1-10 parts by weight, thickener 0.5-200 parts by weight, release agent 0.1-10 parts by weight ,
One or more selected from the group consisting of 5 to 20 parts by weight of general-purpose rubber, 5 to 50 parts by weight of liquid rubber, and 5 to 20 parts by weight of organic solvent was added and blended to impart screen printing properties. The method for forming a sandblast-resistant surface protective film according to claim 1, which is an ink composition.