JPS62168568A - Preparation of sandblast resistance surface protecting film - Google Patents

Abstract

PURPOSE:To improve working environment and prepare a surface protecting film of superb performance by screen printing with screen ink made from an ultraviolet curing rubber-like elastic material as a base and curing by means of irradiation with ultraviolet rays. CONSTITUTION:A composition to form a film for screen printing on an inorganic surface or an organic surface, on which desired engraving is produced, is made from an ultraviolet curing rubber-like elastic material of flexible physical properties of coating carrying a B-6B pencil hardness measured such as urethane acrylate of polyether type, urethane acrylate of polyester type or the like as a base. Necessary amounts of unsaturated monomer of ethylene type, photosensitizer, thickening agent and the like are blended with the composition to prepare a solventless or solvent-free type screen ink having screen printing properties, which is, after being printed, irradiated with ultraviolet rays and cured to impart sandblast resistance properties.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention uses a screen printing ink based on a rubber-like elastic material having ultraviolet ray curability to print on an inorganic or organic surface on which a desired engraving is to be performed. The present invention relates to a method of forming a sandblasting-resistant surface protective film having chemical resistance and removability by screen printing on the surface and then curing it by irradiating it with ultraviolet rays.

(Prior art) Conventional sandblasting methods include: ■ 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 carving a predetermined character, figure, or pattern. etc., and paste it on the surface to be carved.
A master plate for engraving is created by cutting out parts such as letters, figures, patterns, etc. with a knife, etc., and engraving is performed by blowing ultra-hard particles such as metal sand (hereinafter referred to as "Zandblas 1-"), and the synthetic rubber plate is peeled off. How to complete the process by removing: ■ Cut a photosensitive resin plate with a thickness of about 1 to 3 m/m to match the size of the object to be engraved, paste it on the surface to be engraved, and print the letters,
A negative, square, or positive photomask with a figure, pattern, etc. drawn on it is adhered to a photosensitive resin plate, then cured with ultraviolet rays, the photomask is removed, and a developing solution such as an organic solvent or alkaline aqueous solution is used. An original plate for engraving is created by developing the uncured area and drying it using heat or infrared irradiation, and then attaching it to the surface to be engraved, sandblasting,
A method to complete by peeling off the original plate for engraving: 1. Apply a photosensitive resin liquid to the surface to be engraved, cover it with a polyester film, adjust the thickness to about 1 to 3 m/m, and tightly fit a photomask on top of it. Then, the photomask and polyester film are removed, the uncured parts are developed using a developer such as an organic solvent or an alkaline aqueous solution, and the film is dried using heat or infrared irradiation. A method of creating a master plate for engraving, applying it to the surface to be engraved by sandblasting, and then peeling and removing the master plate for engraving. Sandblasting the surface protective film dried by evaporation drying, heat drying, or infrared irradiation drying method at room temperature, and completing the process by peeling off the surface protective film, ■ Utilizing water-dispersed screen printing ink. The method is completed by screen printing on the surface to be engraved, sandblasting the surface protective film dried by evaporation drying, heating drying, or drying using infrared irradiation at room temperature, and peeling off and removing the surface protective film. , etc. are known.

(Problems to be Solved by the Invention) However, these conventional methods have many problems.

First, in the conventional method (3), which uses 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. However, 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.

In addition, it is very time-consuming because letters, figures, patterns, etc. have to be borrowed one by one. Furthermore, since characters, 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 method of creating an original plate for engraving using a photosensitive resin plate according to the conventional method ①, the photosensitive resin plate is cut to match the size of the object to be engraved and pasted, as in the conventional method ②. It took some time to put it on.

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 has poor workability and is harmful to the human body, requiring 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. Furthermore, when using a photomask with characters, figures, patterns, etc. drawn on it that leaves a large amount of uncured portions after exposure, the amount of photosensitive resin that must be developed is naturally large, making it difficult to reuse it. Without it, there would be a lot of waste and the cost would be high. Furthermore, after the development process, it was necessary to perform a drying process using heating or infrared irradiation, which was time-consuming.

Similar to the conventional method (2), the method of preparing an original plate for engraving using a photosensitive resin liquid according to the conventional method (2) has many problems in common. 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 alkaline aqueous solution, which is difficult to work with and is harmful to the human body. I needed to.

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. Furthermore, when using a photomask with characters, figures, patterns, etc. drawn on it that leaves a large amount of uncured portions after exposure, the amount of photosensitive resin that must be developed is naturally large, making it difficult to reuse it. Without it, there would be a lot of waste and the cost would be high. 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.
The photosensitive resin liquid adhering to the surface to be engraved cannot be completely removed, which causes defects to remain on the surface to be sandblasted.

The method of using an organic solvent-based screen printing ink of the conventional method (■) can eliminate the labor and waste of the conventional methods (■ to ■) by screen printing, but the workability is poor because it uses an organic solvent. , was harmful to the human body 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 even causing clogging of the screen plate. Also, depending on the type of solvent used, the screen plate was immersed in the emulsion, which shortened the life of the screen plate.

When a high boiling point solvent is used, the problem of scorching is reduced, but drying becomes more difficult. Both high-boiling point solvents and low-boiling point solvents require time-consuming drying treatments such as evaporation drying at room temperature, heating drying, or drying by infrared irradiation. 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.

Conventional method (2), which uses water-dispersed screen printing ink, has less of the pollution drawbacks of conventional method (2), but the viscosity of the ink changes and the viscosity needs to be adjusted before use. Defects such as clogging of the plate 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.Also, it is difficult to form a thin dry film, which reduces sandblasting resistance and prevents sandblasting. This method had problems such as not being able to form a protective film on the surface.

(Means for Solving the Problems) Therefore, the present inventors conducted long-term sincere research in order to overcome the drawbacks of the conventional methods, 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 elastomer having ultraviolet ray curability to coat an inorganic surface or an organic surface on which a desired engraving is to be performed. In this method, the surface is screen printed and then dried by irradiation with ultraviolet rays to form a sandblast-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. Furthermore, to provide a sandblasting method that accurately reproduces fine characters, figures, patterns, etc. by screen printing, sufficiently withstands sandblasting even with a thin film as thick as 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 having a molecular weight of 1,000 or more and 10,000 or less, 5 parts by weight of a diisocyanate compound, ~190
parts by weight, 1 to 90 parts by weight of dihydric alcohol with a molecular weight of 300 or less, and 2 to 90 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group
It is a rubber-based copolymer having ultraviolet curable properties obtained by uniformly mixing and reacting 25 parts by weight, and its main components are of the following formula; (where, R is an argyl group having 1 to 8 carbon atoms, R3 is H or CH3, R2 are diisocyanate residues, R3 is the residue of dihydric alcohol from which the hydroxyl group has been removed, X is the portion of the diene liquid rubber having the hydroxyl group from which the hydroxyl group has been removed, 1 is 1 to 4, n
is 1 to 12, m represents l<m<3).

Examples of the diene liquid rubber having a hydroxyl group include 1,2-polybutadiene having a hydroxyl group in the molecule, 1.4
-Polybutadiene, 1,2-pentadiene, styrene-
Butadiene copolymer, acrylonitrile-butadiene copolymer, isoprene, etc. with a number average molecular weight of 1.00
It is a polymer of about 0 to 10,000, the position of the hydroxyl group is arbitrary, and the number of hydroxyl groups in the molecule (m) is about l<m<3.

Examples of the ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and polypropylene glycol monomethacrylate.

.

Examples of diisocyanate compounds include tolylene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-difhenylmethane diisocyanate-1, 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, L3-7'tanediol, 1,4-
Butanediol, 1,5-bentanediol, 1,6-
Hexanediol, trimethylolpropane monoacrylate, trimethylo-.

Examples include propane monomethacrylate, glycerol-α-monoallyl ether, and the like.

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 having a molecular weight of 300 or less are preferably 5 to 190 parts by weight and 1 to 90 parts by weight, respectively, based on 100 parts by weight of the diene liquid rubber having a hydroxyl group, and the total amount of the two components is the molecular weight. 1,00
Liquid rubber having 0 to 10,000 hydroxyl groups 10
If the amount exceeds 280 parts by weight compared to 0 parts by weight, the properties of the rubber (chemical resistance, water resistance, flexibility, elasticity, elongation, resilience against bending) will be impaired, and the resistance to plating and soldering (metal resistance) will be impaired. The chemical resistance and water resistance of the adhesive and the heat resistance of the solder decrease, resulting in poor removability. 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 I segment will not be carried out well, resulting in high strength and high strength. Since it becomes difficult to obtain an elongated photocured product, re-peelability after treatment deteriorates, which is not preferable. The problem with removability is that the film strength is weak and breaks occur during peeling. Here, the expression (
The continuous urethane bond n in 1) represents a hard segment, and the X in formula (I) represents a soft segment and corresponds to the rubber main chain. Formula (1) consists of these two segments, and the soft 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 a soft segment is used, it may peel off from the base material during soldering, but if a hard segment is incorporated, it has the effect of improving adhesion to the base material.

The amount of the ethylenically unsaturated monomer having a hydroxyl group is preferably 2 to 25 parts by weight based on 100 parts by weight of the diene liquid rubber having a hydroxyl group, and if it exceeds 25 parts by weight, unreacted components (total The generation of unreacted components causes problems such as a decrease in yield and poor storage stability, and the formation of a polymer different from the main component formula (1). The production of a polymer having a structure different from I) is undesirable in terms of physical properties, and only the ethylenically unsaturated monomer having a certain amount of hydroxyl groups contributes to the addition polymerization, and the remainder remains as unreacted substances, which is undesirable. Furthermore, even if the amount does not reach 2 parts by weight, unreacted components (all blended components) are generated during the polymerization step, and a polymer different from the main component formula (I) is generated, and the generation of unreacted components is The formation of polymers with a structure different from 2N) is unfavorable in terms of physical properties, and there is a problem of poor photosensitivity when addition polymerized. .

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 (1).

The rubber-like elastic body having ultraviolet curability suitable for use in the present invention is polyether-based urethane acrylate or polyester, which has flexible coating film properties after ultraviolet curing and has a pencil hardness of B to 6B. For polyether-based urethane acrylates, for example, ■ the ends of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. are modified with a diisocyanate compound such as 2,4-tolylene diisocyanate, that is, both ends are modified. N
A CO group (isocyanate group) prepolymer and ■
A polyether system made by reacting an ethylenically unsaturated monomer having one hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, etc. There are urethane acrylates, and polyester-based urethane acrylates include, for example: ■Polyester consisting of ethylene glycol and adipic acid, ■Polyester consisting of 6-hexanediol and adipic acid, and polyester consisting of ethylene glycol, adipic acid, and triethylene glycol. A prepolymer whose terminals are modified with a diisocyanate compound such as 2.4-1-lylene diisocyanate, that is, both terminals are made into NGO groups, and an ethylenically unsaturated monomer having one hydroxyl group as in (1) above. There is a polyester-based urethane acrylate made by reacting (1) and (20) at a ratio of 1:2. Here, the physical properties of the coating film after UV curing are flexible, and the standard is pencil hardness B to 6B.
Benzoin, benzoin methyl ether, benzophenone, Michler's ketone, azobisisobutyronitrile,
When a photosensitizer such as benzyl dimethyl ketal, 2-methylanthraquinone, or 2,2-jethoxyacetophenone is added and UV irradiation is applied until the acryloyl group (or methacrylate group) has fully reacted, the physical properties of the cured film change. It has a pencil hardness of B to 6B, meaning 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 inhibitors, colorants, antifoaming agents, thickeners, release agents, general-purpose rubbers, liquid rubbers, and a small amount of organic solvents are added and blended as necessary to provide screen printing properties. This is an ink composition.

Examples of the ethylenically unsaturated monomer include the aforementioned ethylenically unsaturated monomers having a hydroxyl group, methyl methacrylate, ethyl methacrylate, butyl meccrylate-1, glycidyl methacrylate, 1,4-butylene dimethacrylate, and ethylene glycol dimethacrylate. -1. Methacrylates such as diethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1
, 6-hexane diacrylate, acrylates such as diethylaminoethyl acrylate, methacrylic acid, acrylic acid, acrylonitrile, acrylamide, N-methylolacrylamide, styrene, vinyltoluene, α
-Methylstyrene, vinyl acetate, N-vinyl-2-pyrrolidone, diallyl phthalate, etc., and their blending amounts are as follows:
For 100 parts by weight of the above-mentioned ultraviolet curable rubber-like elastic body, one or more of them are used in an amount of 10 to 2
00 parts by weight.

As photosensitizers, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, benzophenone, Michler's ketone, 1
-Naphthalenesulfonyl chloride, 2.5-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, 7zoisobutyronitrile, 1-azobis-
Examples include 1-cyclohexanecarbonitrile, benzyl dimethyl ketal, 2-methylanthraquinone, biimidazole, thioxanthone, 2,4-diisopropylthioxanthone, 2,2-jethoxyacetophenone, benzoin peroxide, 2,4-dichlorobenzoyl peroxide, etc. The compounding amount is 0.1 to 10 parts by weight of one or more of them, which is the usual amount, per 100 parts by weight of the above-mentioned ultraviolet curable rubber-like elastic body.

Thermal polymerization inhibitors include hydroquinone, t-butylcatechol, O-dinitrobenzene, 〇-nitrophenol, m-nitrophenol, p-nitrophenol, 2
, 4-dinitrophenol, 2.4.6-trinitrophenol, phenothiazine, ferric chloride, etc., and the blending amount is one type or Two or more kinds are used in a normally used amount of 0.01 to 1.0 parts by weight.

The coloring agent may be a dye or a pigment, and the blending amount is 100% of the above-mentioned ultraviolet curable rubber-like elastic material.
It is used in a commonly used amount of 0.001 to 10 parts by weight.

Examples of antifoaming agents include silicone-based, acrylic-based, polyglycol-based, and polyether-based surfactants. The amount usually used is 0.
It is used in an amount of 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 kinds 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, the amount usually used, 0.1
~10 parts by weight is used.

General-purpose rubbers include polybutadiene, isoprene, chlorosulfonated polyethylene, natural rubber, polybutylene, etc., and the blending amount is one or more of them per 100 parts by weight of the ultraviolet-curable rubber-like elastic material. It is used in a normally used amount of 5 to 20 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 less polluting and less harmful.
Unfavorable from the viewpoint of workability.

As the liquid rubber, there is a liquid type of the above-mentioned general-purpose rubber type, and the blending amount is 5 to 50 parts by weight of one or more types per 100 parts by weight of an ultraviolet curable rubber-like elastic body. Used in parts by weight. As with general-purpose rubber, it may be added under particularly severe conditions to improve resistance.
Provides a cured product with improved rubber elasticity and chemical resistance. The amount of compounding depends on the effect on UV curing properties and screen ink properties, just like general-purpose rubber, and the effect when added in amounts exceeding 2 is the same as that of general-purpose rubber, but organic solvents are not used together. Therefore, there are no problems with pollution, workability, 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 blending amount 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.

(Example) Hereinafter, the present invention will be explained based on examples.

Example 1 (Example of polymerized rubber-based copolymer having ultraviolet curable properties) 2.4-Tolylene diisocyanate-1-29.2g was dissolved in 87.6g of dioxane, and the solution was mixed with 500ml of dioxane. 4
While stirring under nitrogen atmosphere, 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 the dropwise addition, the reaction temperature was maintained at 45-50℃, and after the dropwise addition was completed, the reaction temperature was maintained at 45-50℃, 8
Allowed time to react. Thereafter, a solution containing 10 g of 2-hydroxyethyl methacrylate, 0.15 g of hydroquinone, and 0.075 g of triethylenediamine dissolved in 33 g of dioxane was added using a dropping funnel. The reaction solution was kept at 75-80°C during the dropwise addition, and after the dropwise addition was completed, the temperature was kept at 75-80°C.
, and reacted for 2 hours. Furthermore, Poly M R-45
0 (hydroxyl group-terminated polybutadiene liquid rubber, average molecular weight 2
, 800, hydroxyl group content 0.83 meg/g, Idemitsu Petrochemical.

100 g of (manufactured by I) was dissolved in 300 g of dioxane, and the solution was placed in another 10100 O reactor, and the pre-reactant was added using a dropping funnel while stirring under a nitrogen atmosphere. During the dropwise addition, keep the reaction solution at 75-80"C and keep it at 75-80"C after the dropwise addition.
The reaction was carried out at 80°C for 18 hours, and the reaction was completed when it was confirmed by infrared absorption spectrum that the absorption of isocyanate groups had disappeared.

While stirring the beaker containing 5,400 m6 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 Irgacure 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 the tetrahydrofuran was evaporated to dryness. The thickness after drying was 100 μm.

Next, an ultra-high-pressure mercury lamp (output 3 kl @ manufactured by Okuku Seisakusho) 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 with a tensile tester are tensile strength 120k.
g/cm, elongation 250%, JIS hardness (Shore D)
It was 70.

Large-scale ink (example of solvent-free screen ink having screen printing properties based on a rubber-like elastic body having ultraviolet curability) Based on the rubber-based urethane acrylate described in Example 1, an ethylenically unsaturated monomer Ink A was added with additives such as polyester, photosensitizer, etc., and ethylenically unsaturated monomer, photosensitizer, etc. were added to the commercially available polyether urethane acrylate "Goselac UV2000-BJ" as a base. Ink B was prepared by adding the following agent.The formulation contents of Inks A and B are shown in Table 2.

Table 2 (Composition table) 1) Manufactured by Toshi ■, product name 2) Manufactured by Nippon Aerosil ■, product name 3) Manufactured by Nippon Mistron ■, product name 4) Manufactured by Sannopco ■, product name 5) Middle East Oil ■, product name In the case of ink A, the preparation method is to stir and dissolve the rubber-based urethane acrylate described in Example 1 with N-vinyl-2-pyrrolidone and ethylcarpitol acrylate,
After dissolution, all of the above additives were added to the kneaded solution and stirred again.

Next, pass the ink roll through the ink roll three times in total to ink the ink A.
And so. For ink B (7), [Goselac tlV2
000B J was stirred and dissolved with N-vinyl-2-pyrrolidone and ethylcarpitol acrylate, and after dissolution, all of the above additives were added to the kneaded solution and stirred. 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 carried out using a BH type viscometer (manufactured by Tokyo Keiki).
It was carried out at 5°C.

Example 311 - (Screen printing) Screen printing was performed using inks A and B prepared in Example 2 above. Screen printing conditions were: screen mesh 150 mesh, screen emulsion thickness 50μ
Manual screen printing was performed on the glass plate using a screen plate with a fine line resolution pattern and a urethane squeegee with a hardness of 6o. The results are shown in Table 4.

Table 4 1) After ultraviolet curing (conditions described in Example 4), measurements were taken using an ``outer micrometer'' manufactured by Mitoyo Seisakusho (1 example).
- (Curing by ultraviolet rays) Inks A and B printed on the glass plate of Example 3 were cured under the following curing conditions.

Curing conditions: Using an ultra-high pressure mercury lamp "Polymer Printer" (output 3 kW, @Oak Manufacturing), the distance between the glass plate and the lamp was 50 cm, and the exposure time was 30 seconds.

After curing, both inks A and B were in a tank-free state, and there were no defects such as wrinkles in the ink due to uncuring. Pencil hardness of ink A is B1 Pencil hardness of ink B is 6B
Met. .

Example 5 (Sandblasting, etching with hydrofluoric acid, etc., and re-peeling of the surface protective film) The inks A and B printed on a glass plate in Example 4 and then cured were subjected to sandblasting under the following sandblasting conditions. .

Sandblasting conditions: Sandblasting machine rTDH-40
1J (manufactured by Tokyo Shibaura Electric ■), sandblasting material frequency "Alundum #150j (manufactured by Nippon Karli 1~ Co., Ltd.), nozzle diameter 15 mm, air pressure 4 kg/cm2, distance between glass plate and nozzle 10 cm, The glass plate printed with ink A was designated as glass plate A, and the glass plate printed with ink B was designated as glass plate B.

After sandblasting, the surface protective films of glass plates A and B were not soaked in any way.

Next, glass plates A and B were subjected to sandblasting treatment.
was etched using a mixture of hydrofluoric acid and sulfuric acid under the following etching conditions.

Etching conditions: Pour about half of a 1:1 mixture of hydrofluoric acid and sulfuric acid into a 1x volume polyethylene band, and sandblast glass plates A and B.
It was immersed in it. After soaking for 2 minutes, take the two glass plates outside, transfer them to a plastic bucket that is about half full of water, and use your rubber-gloved hands to brush the front and back of the glass plates, that is, both sides, using a regular tank. Washed with water. By brushing glass plates A and B
The surface protective film that had adhered to the surface was completely removed. Next, the peeled glass plates A and B are washed with tap water, and the water is wiped off with a cloth to form glass plates A' and B'.
Here, glass plate A' is obtained by etching glass plate A, and glass plate B' is obtained by etching glass plate B. The parts of glass plates A' and B' that were covered with the surface protective film were both transparent and without any scratches.
The portions not covered by the surface protective film were opaque and had engravings approximately 0.1 mm deep.

(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, since it uses a screen printing method, precise sandblasting is possible, and since it uses ultraviolet curing, a surface protective film can be formed in a few seconds to several tens of seconds. Therefore, it 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 has a cured thickness of 3
Although it is a thin film of 0 μm, it exhibits sufficient sandblasting resistance, and is not only resistant to sand blasting, but also has excellent chemical resistance. It is possible to perform chemical treatments such as sandblasting before or after sandblasting, and the treated surface protective film can be easily peeled off by soaking it in water and brushing it, or by rolling up the edges of the film by hand. This has the effect of being able to.

Claims (1)

[Scope of Claims] 1. Using a surface protective film deposited on an inorganic or organic surface on which a desired engraving is to be performed, a desired engraving is performed by sandblasting, and then the surface protective film is peeled off and removed. In the sandblasting engraving method, the surface protective film is prepared into a solventless or solvent-free screen ink having screen printing properties, mainly based on a rubber-like elastic material having ultraviolet ray curing properties, and using this ink. 1. A method for forming a sandblast-resistant surface protective film, which comprises screen printing on an inorganic or organic surface on which a desired engraving is to be made, and then curing the surface by irradiating it with ultraviolet rays to form a surface protective film. 2. The rubber-like elastic body having ultraviolet curable properties includes 100 parts by weight of a liquid rubber having a hydroxyl group with a molecular weight of 1,000 or more and 10,000 or less, and 5 to 190 parts by weight of a diisocyanate compound.
parts by weight, 1 to 90 parts by weight of dihydric alcohol with a molecular weight of 300 or less, and 2 to 2 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group
It is a rubber-based copolymer with ultraviolet curable properties made by uniformly blending and polymerizing four components consisting of 5 parts by weight, and its main components are as follows: ▲There are mathematical formulas, chemical formulas, tables, etc.▼... (I) (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 dihydric alcohol residue excluding the hydroxyl group, and X is a diene liquid having a hydroxyl group. The part of the rubber excluding the hydroxyl group, l is 1 to
4. The method for forming a sandblast-resistant surface protective film according to claim 1, wherein n is 1 to 12 and m is 1<m<3. 3. The rubber-like elastic body having ultraviolet curable properties has flexible coating film properties after being cured by ultraviolet rays, and has a pencil hardness value of B~
The method for forming a sandblast-resistant surface protective film according to claim 1, wherein the polyether-based urethane acrylate or polyester-based urethane acrylate is 6B. 4. Solventless having the above-mentioned screen printing properties;
Alternatively, the composition of the solvent-free screen ink is based on 100 parts by weight of an ultraviolet-curable rubber-like elastic material, 10 to 200 parts by weight of an ethylenically unsaturated monomer, and 0.1 parts by weight of a photosensitizer. ~10 parts by weight, thermal polymerization inhibitor 0.01-10 parts by weight, colorant 0.001-10 parts by weight
parts by weight, antifoaming agent 0.1-10 parts by weight, thickener 0.5-2
00 parts by weight, 0.1 to 10 parts by weight of a release agent, 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. 2. The method for forming a sandblast-resistant surface protective film according to claim 1, which is an ink composition prepared by adding and blending at least one of the following species to impart screen printing properties.