JPS62168569A - Preparation of ultraviolet cured transient surface protecting film - Google Patents

Abstract

PURPOSE:To prepare a protecting film of superb chemical resistance and heat resistance capable of being surface-treated very accurately by utilizing an ink of specific composition which is made from an ultraviolet ray cured rubber-like elastic material as a base and has screen printing properties. CONSTITUTION:An ink composition to be utilized is a solventless or solvent-free type ink having screen printing properties, which is made from ultraviolet curing rubber-like elastic materials such as urethane acrylate of polyether type, urethane acrylate of polyester type and the like having a B-6B pencil hardness value as a base and unsaturated monomer as essential component. Necessary amounts of photosensitizer, heat polymerization preventing agent, coloring agent, anti-foam agent, general-purpose rubber, some of organic solvent and the like are added and blended with said composition, and the resulting compound is coated with screen printing or the like, cured by irradiation with ultraviolet rays to obtain a transient surface protecting film.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for forming an ultraviolet curable temporary surface protective coating, an ultraviolet curable rubber-like elastic body, and a screen ink using the same. In more detail, the metal surfaces of copper-clad laminates used in printed wiring boards, or the inorganic surfaces of steel plates, aluminum plates, copper plates, and other inorganic surfaces such as quartz plates and inorganic glass plates, are coated with electrolytic plating, non-copper plates, etc. Through surface treatment methods such as electrolytic plating and soldering,
The present invention relates to a method of forming a temporary surface protective coating used in selective surface treatment, a rubber-like elastic body used therein, and a screen ink.

(Prior art) Conventionally, surface treatment methods such as electrolytic plating, electroless plating, and soldering are: ■ Laminating an adhesive layer on crepe paper or polyester film on the surface of a material with an inorganic surface to be treated. Apply the adhesive tape, immerse it in a plating liquid tank or solder liquid tank, perform the desired plating or soldering process, take out the treated material from the plating liquid tank or solder liquid tank, and cool it to room temperature. Then, the adhesive tape is peeled off, washed with a cleaning solvent such as Freon (product name: DuPont, USA), and then dried. (products sold by several companies) are heated and pasted onto the surface of the material having the desired inorganic surface to be treated,
A negative or positive photomask is placed on top of the photomask, then UV curing is performed, and the photomask is removed.
By developing the uncured area using a developer such as an organic solvent or aqueous alkaline solution and drying it using heat or infrared irradiation, a protective coating film is formed on the next surface, which can be used in a plating bath or The material is immersed in a solder solution bath, subjected to the desired plating or soldering treatment, and the treated material is removed from the plating solution bath or solder solution bath and cooled to room temperature. The next surface protective coating is removed using a removal treatment solution (for example, an organic solvent such as methylene chloride, trichloroethylene, or a strong alkaline aqueous solution such as an aqueous sodium hydroxide solution), suitable for a cleaning process such as washing with water, and then dried. ■ How to complete using a plating resist material solution dissolved in an organic solvent (
A product sold by several companies such as Tokyo Ohka Kogyo ■) is coated on the surface of the material with the desired inorganic surface to be treated using a coating machine such as a spin coater or Whaler, and then heated with a dryer etc. The organic solvent is removed by drying using a drying machine, a negative or positive photomask is adhered thereon, and then cured with ultraviolet rays, the photomask is removed, and an organic solvent or alkaline aqueous solution, etc. The uncured area is developed using a developer solution and dried using heating or infrared irradiation to form a second surface protective coating film, which is then immersed in a plating solution tank or solder solution tank.
After performing the desired plating and soldering processing, the treated material is removed from the plating solution bath or soldering solution bath, cooled to room temperature, and then treated with a stripping solution (
For example, the surface protective coating is removed using an organic solvent such as methylene chloride or trichloroethylene, or a strong alkali aqueous solution such as sodium hydroxide, and then subjected to a cleaning process such as water washing, and then dried. The method to be completed: ■ Screen printing a heat-curable screen printing ink onto the surface of the material having the desired inorganic surface to be treated, followed by heat treatment to form a second surface protective coating; The material is immersed in a plating liquid bath or a soldering liquid bath, subjected to desired plating or soldering treatment, and the treated material is taken out from the plating liquid bath or soldering liquid bath, cooled to room temperature, and then,
- A method is known in which the surface protective coating film is completely removed by physically removing the protective film.

(Problems to be Solved by the Present Invention) However, such conventional methods have many problems as follows.

Although the method of pasting adhesive tape (conventional method ①) is low cost, it has poor chemical resistance to plating solutions, often peels off during the plating process, and when the soldering process is performed, the solder solution is heated to 250°C. Because it is used at ~260°C, the adhesive layer melts, and when the adhesive tape is peeled off after treatment, the adhesive transfers and remains on the surface of the material that has the desired inorganic surface to be treated, resulting in the adhesive layer melting. It was difficult to remove the agent. Moreover, when the covering parts are scattered, it is necessary to cut the adhesive tape to the size of the covering parts and stick them one by one, which is time-consuming.

The dry film type resist h for plating according to the conventional method (1) requires a special laminating machine to be applied by heating, and the developer used for the development process is an organic solvent or alkaline aqueous solution that is toxic to the human body. It was necessary to install a dedicated developing machine and draft. Furthermore, the organic solvent or alkaline aqueous solution used for development must be replaced when used for a long period of time, requiring disposal. or,
After the development process, it was necessary to perform a drying process using heat or infrared irradiation, which was time-consuming. Furthermore, when removing the film after plating and soldering, a special stripping solution must be used, which causes similar problems.

In the method using a solution of a resist material for plating treatment dissolved in an organic solvent in the conventional method (3), the solution is applied.

A dedicated developer and ventilation equipment such as a draft were required for drying, as the developing solution used for processing is an organic solvent or alkaline aqueous solution that is toxic to the human body. . Further, the developing solution such as an organic solvent or an alkaline aqueous solution used for development must be replaced when used for a long period of time, requiring disposal. Further, after the development process, it was necessary to perform a drying process using heating or infrared irradiation, which was time-consuming.

Further, when removing the film after the plating process and the soldering process, a special peeling solution must be used, resulting in similar problems.

The conventional method (ii) using a heat-curable screen printing ink forms a primary surface protective film by screen printing and heat treatment, so there is no need for development processing or equipment necessary for development processing.

Moreover, the film can be peeled off simply by turning it over by hand, and the problems of the conventional methods (1) to (3) can now be overcome. However, because it hardens by heating, for example, printed wiring boards (
When using a substrate made by laminating a layer of glass cloth impregnated with epoxy resin or a layer of paper impregnated with phenol resin and a thin copper layer using an adhesive, the substrate deforms due to the difference in the coefficient of expansion and contraction of each layer. This affected plating and soldering processes, making it impossible to perform processes with high precision.

Further, curing by heating has a problem in that a curing time of at least 5 to 10 minutes is required.

(Means for Solving the Problems) As a result of intensive research to overcome the drawbacks of the conventional methods, the present inventors have developed a solvent-less or solvent-based method based on a rubber-like shell having ultraviolet curable properties. This invention was achieved by producing a free-type screen ink, (1) applying screen printing or coating with a thin film coating machine to the surface to be treated, and (2) forming a primary surface protective coating film by curing with ultraviolet rays. I ended up doing it.

That is, the present invention provides a method for forming a primary surface protective coating film used when selectively surface-treating an inorganic surface by surface treatment methods such as electrolytic plating, electroless plating, and soldering. A solventless or solvent-free screen ink having screen printing properties based on a rubber-like elastomer is produced, and this is used to screen print or print on an inorganic or organic surface to be covered with a desired coating. , relates to a method for forming a temporary surface protective coating film cured by UV rays, characterized in that a second surface protective coating film is formed by coating with a thin film coating machine and then curing by irradiating ultraviolet rays. .

Still another object of the present invention is that the rubber-like elastic body having ultraviolet ray curing properties has a molecular weight of 1 LOOO or more.
Consisting of 100 parts by weight of a liquid rubber having the following hydroxyl group, 5 to 190 parts by weight of a diisocyanate compound, 1 to 90 parts by weight of a dihydric alcohol having a molecular weight of 300 or less, and 2 to 25 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group. It is a rubber-based polymer with ultraviolet curable properties made by uniformly blending and polymerizing four components, and its main components are of the following formula: (where R is an alkyl group having 1 to 8 carbon atoms, R1 is H or C1 ( 3, R2 is a diisocyanate residue, R3 is a residue of a dihydric alcohol with the hydroxyl group removed, X is a part of a diene liquid rubber having a hydroxyl group with the hydroxyl group removed, β is 1 to 4, n
is 1 to 12, and m represents l<m<3.

Still another object of the present invention is that the composition of a solvent-less or solvent-free screen ink having screen printing properties is based on 100 parts by weight of a rubber-like elastic material having ultraviolet curable properties, Saturated monomer 10 to 200 parts by weight, photosensitizer 0.1 to 10 parts by weight, thermal polymerization inhibitor 0.01 to 10, colorant 0.001
~10 parts by weight, antifoaming agent 0.1-10 parts by weight, thickener 0.
5 to 200 parts by weight, 0.1 to 10 parts by weight of release agent,
An ink composition containing one or two selected from the group consisting of 5 to 20 parts by weight of a general-purpose rubber, 5 to 50 parts by weight of a liquid rubber, and 5 to 20 parts by weight of an organic solvent, and has ultraviolet curability. To provide a screen ink for screen printing using a rubber-like elastic body.

The ultraviolet curable rubber-like elastic body used in the present invention is polyether urethane acrylate or polyester urethane, which has flexible coating properties after ultraviolet curing and has a pencil hardness value of B to 6B. Selected from acrylate.

Although the primary surface protection coating film of the present invention is thinner than conventional primary surface protection coating films, it has excellent chemical resistance to plating solutions, heat resistance during soldering, and re-peelability after such processing. Because of its excellent properties, by using the secondary surface protective coating film of the present invention, it is possible to significantly reduce the defects that occur on land using the conventional primary surface protective coating film. Further, according to the present invention, the safety and workability of the conventional method can be improved, waste in the manufacturing process can be eliminated, and the number of steps and costs can be significantly reduced. In addition, screen printing allows for accurate pattern reproduction, and even with a film thickness of 30 μm, it has excellent chemical resistance to plating solutions and heat resistance during soldering, and is easy to re-peel, making it suitable for plating and soldering. , can provide a hassle-free surface treatment method. Furthermore, there is no need to worry about deformation of the surface-treated material due to heat curing, and it is possible to perform surface treatment with high precision by irradiating ultraviolet rays for several seconds to several tens of seconds.

The structure and operation of the present invention will be explained below.

The rubber-based copolymer having ultraviolet curable properties as a rubber-like elastic body after being cured by ultraviolet rays 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, 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 with ultraviolet curable properties obtained by uniformly mixing and reacting 25 parts by weight, and its main component is the following formula: % formula % (1) (where R is an alkyl group having 1 to 8 carbon atoms , R1 is H or CH3, R2 is a diisocyanate residue, R3 is a residue of a dihydric alcohol from which the hydroxyl group has been removed, X is the portion of the diene liquid rubber having a hydroxyl group from which the hydroxyl group has been removed, β is 1 to 4, and n is 1 to 12, m indicates 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-pencdiene, styrene-
Butadiene copolymer, acrylonitrile-cyclodiene copolymer, isoprene, etc. with a number average molecular weight of 1.000
It is a polymer of about 10,000 to 10,000, 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 acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and polypropylene glycol monomethacrylate.

Examples of the diisocyanate compound include tri-1/lene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 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, 1,3-butanediol, and 1,4-propylene glycol.
Butanediol, 1,5-pentanedionope 1,6-
Hexanediol, trimethylolpropane monoacrylate, trimethylolpropane monomethacrylate,
Examples include glycerol-α-monoallyl ether.

Next, compositional limitations of the ultraviolet curable rubber-like elastic body according to the present invention will be explained.

The above diisocyanate compound and dihydric alcohol having a molecular weight of 300 or less are 100% diene liquid rubber having a hydroxyl group.
It is preferably 5 to 190 parts by weight and 1 to 90 parts by weight, respectively, based on the weight part, and the total amount of the two components has a molecular weight of 1.0.
Liquid rubber having 00 or more and 10,000 or less hydroxyl groups 1
If the amount exceeds 280 parts by weight, the properties of the rubber (chemical resistance, water resistance, flexibility, elasticity, elongation, resilience to bending) will be impaired, and the resistance to plating and soldering (metal resistance) will be impaired. The chemical resistance and water resistance of solder and the heat resistance of solder deteriorate, and re-peelability becomes worse. 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 removability 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 formula (1
) The continuous urethane bond n in the formula (1) represents a hard segment, and the X in formula (1) 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, and the hard physical properties, such as strength, toughness, and tear strength, appear from the hard segment. emerging from the segment. 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 like the rubber-like elastic body of the present invention, it has the effect of improving the adhesion to the base material. be.

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 (I) is produced, and the generation of unreacted components causes problems such as reduced yield and poor storage stability.
Formation of a polymer having a structure different from the formula 1) is unfavorable in terms of physical properties.

Furthermore, only a certain amount of ethylenically unsaturated monomers having hydroxyl groups contribute to the addition polymerization, and the remainder remains as an unreacted material, which is not preferred. Furthermore, even if the amount does not reach 2 parts by weight, unreacted components (all blended components) will be generated during the polymerization step, and a polymer different from the main component (+) formula will be generated.
This causes problems such as a decrease in yield and poor storage stability, and the formation of a polymer having a structure different from that of formula (1) is unfavorable in terms of physical properties, resulting in the problem of poor photosensitivity when subjected to addition polymerization. . As described above, polymerization is limited by the molecular weight and number of reactive groups of each component, and the range of main components is limited by formula (1).

Table 1 Rubber-like elastic bodies having ultraviolet curability suitable for use in the present invention are polyether-based urethane acrylates whose physical properties after ultraviolet curing are flexible and whose pencil hardness values are B to 6B. , or a polyester urethane acrylate, such as (a) polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. whose terminals are modified with a diisocyanate compound such as 2.4-) lylene diisocyanate. In other words, prepolymers with NCO groups (incyanate groups) at both ends, and ethylenic polymers with one hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, etc. There are polyether-based urethane acrylates that are reacted with saturated monomers in a ratio of (a):(b) = 1:2. Examples of polyester-based urethane acrylates include (C) polyesters made of ethylene glycol and adipic acid. , the ends of a polyester consisting of 1,6-hexanediol and adipic acid, ethylene glycol, adipic acid, and triethylene glycol are modified with a diisocyanate compound such as 2,4-tolylene diisocyanate, that is, both ends are modified. N.C.O.
(incyanate group) prepolymer and the above-mentioned (incyanate group)
There is a polyester urethane acrylate obtained by reacting an ethylenically unsaturated monomer having one hydroxyl group such as b) in a ratio of (C):(b)-1:2.

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-jethoxyacetophenone, etc., and apply ultraviolet light until the acryloyl group (or meccrylate group) fully reacts. When irradiated, the physical properties of the cured film have a pencil hardness of B to 6B, which means that it is rubber-like.

A solventless 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, and contains an ethylenically unsaturated monomer as an essential component. Add one or more selected from photosensitizers, thermal polymerization inhibitors, colorants, antifoaming agents, thickeners, release agents, general-purpose rubbers, liquid rubbers, and a small amount of organic solvents. This is an ink composition prepared to impart screen printing properties.

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-butylene dimethacrylate, ethylene glycol dimethacrylate, and diethylaminoethyl. Methacrylates such as methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1,6-
Acrylates such as hexane diacrylate and diethylaminoethyl acrylate, methacrylic acid, acrylic acid, acrylonitrinobeacrylamide, N-methylolacrylamide, styrene, vinyltoluene, α-methylstyrene, vinyl acetate, N-vinyl-2-pyrrolidone, diallyl The compounding amount is 10 to 200 parts by weight of one or more of the above-mentioned rubber-like elastic materials having ultraviolet curable properties.
Add part by weight.

Examples of photosensitizers include benzoin, benzoin methyl ether, benzoin isopropyl ether, penzoin butyl ether, benzophenone, Michler's ketone, 1
-Naphthalenesulfonyl chloride, 2,5-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, azoisobutylnitrile, 1-azobis(ni-1-cyclohexane)benzyl dimethyl ketal, 2-methylanthraquinone, biimidazonobethioxanthone , 2,4-diisopropylthioxanthone, 2,2-jethoxyacetophenone, pentyne peroxide, 2,4-cyclopenzoyl peroxide, etc., and the blending amount is determined by the above-mentioned rubber-like elasticity having ultraviolet curable property. One or more of them is added in a normally used amount of 0.1 to 10 parts by weight per 100 parts by weight.

Thermal polymerization inhibitors include hydroquinone, 1-butylcatechol, o-dinitrobenzene, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2
,4-dinitrilophenonobe2.4.6- ) IJ
There are nitrophenopephenothiazine, ferric chloride, etc., and the amount of one or more of them is usually used, usually 0. It is used in an amount of .01 to 1.0 parts by weight.

The coloring agent may be a dye or a pigment, and the amount of the coloring agent may be the same as the above-mentioned ultraviolet curable rubber-like elastic material 10.
The amount usually used is 0.001 to 10 parts by weight per 0 parts by weight.

Antifoaming agents include silicone-based, acrylic-based, polyglycol-based, and polyether-based surfactants, and the blending amount is one of them or Amount of two or more types usually used, 0
．． Add 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 added in a normally 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. The amount usually used for seeds or more, 0.1 ~
Add 10 parts by weight.

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 UV curability and the properties of the screen ink. If added in excess of the above amount, the rubber is a non-photosensitive material, so the UV curability will decrease, and the organic Rubber is added to the ink as a solution of general-purpose rubber dissolved in a solvent, which is unfavorable from the standpoint of pollution and workability.

As the liquid rubber, there is a liquid type of the above-mentioned general-purpose rubber type, 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. ~50 parts by weight is used. 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 properties, just like general-purpose rubber, and the effect when added in excess of the above-mentioned amount is the same as that of general-purpose rubber, but since no organic solvent is used in combination, There are no problems with pollution, workability, etc.

In addition, when adding an organic solvent, for example, in the form of a solution of general-purpose rubber dissolved in an organic solvent, it is added as necessary if necessary to impart screen printing characteristics, and the type of organic solvent is arbitrary, and its formulation is 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 such that the evaporation of the organic solvent does not affect the screen printing properties, worsen the working environment, or cause clogging of the screen, and the amount of rubber-like elastic material that has ultraviolet curable properties is sufficient. The amount does not have any negative effects such as a decrease in the curing speed or poor curing, and the amount is usually used, although the amount varies depending on the dissolving ability of the solvent.

(Example) The present invention will be explained below based on examples.

Example 1 (Example of polymerized rubber copolymer with UV curability) 2.4-) 29.2 g of lylene diisocyanate was dissolved in 87.6 g of dioxane, and the solution was placed in a 500 ml reactor. While stirring under a nitrogen atmosphere, a solution of 7.5 g of 1,4-butanediol dissolved in 22.5 g of dioxane was added via a 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. Then 110 g of 2-hydroxyethyl methacrylate and 0.15 g of hydroquinone.

0.075 g of triethylenediamine is 33 g of dioxane
g solution was added via addition funnel. During dripping,
The reaction solution was kept at 75-80°C, and after the dropwise addition was completed, the temperature was 75-80°C.
The reaction was carried out at 0°C for 2 hours. Furthermore, Poly bd R
-45D (hydroxyl group-terminated polybutadiene liquid rubber, average molecular weight 2.800, hydroxyl group content 0.83 meg/g, HOOg manufactured by Idemitsu Petrochemical ■) was dissolved in 300 g of dioxane,
The solution was placed in another 10100 O reactor and the pre-reactant was added via addition funnel while stirring under nitrogen atmosphere.

During the dropwise addition, the reaction solution was kept at 75 to 80°C, and after the dropwise addition
The reaction was carried out at 5 to 80°C for 8 hours, and the reaction was terminated when it was confirmed by infrared absorption spectrum that the absorption of incyanate groups had disappeared.

While stirring the beaker containing 5,400 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. Dissolving the urethane acrylate in tetrahydrofuran,
Irgacure 651 (manufactured by Ciba Geigy) as a sensitizer
A photosensitive solution was prepared by adding and dissolving 5% of the following. 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 (output 3klll, manufactured by Oak) 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 1
The weight was 20 kg/cm, the degree of elongation was 250%, and the JIS hardness (Shore D) was 70.

Example 2 (Example of a solvent-free screen ink having screen printing properties based on a rubber-like elastic material having ultraviolet curable property) Based on the rubber-based urethane acrylate described in Example 1, an ethylenically unsaturated monoplane ink was used. Additives such as , photosensitizer, etc. are added to the ink.
Ink B was prepared using 1V 2000 BJ as a base and adding additives such as an ethylenically unsaturated monomer, a photosensitizer, and the like. The formulation contents of inks Δ and B are shown in Table 2.

Table 2 1) Made by Toshi ■ Product name 2) Made by Nippon Aerosil ■ Product name 3) Made by Nippon Mistron ■ Product name 4) Made by Sannopco ■ Product name 5) Made by Middle East Oil ■ Product name The preparation method is for ink A. The rubber urethane acrylate described in Example 1 was stirred and dissolved with N-vinyl-2-pyrrolidone and ethylcarpitol acrylate, and after dissolving, all of the above additives were added to the solution and stirred again. I dialed the number. In the case of ink B, "Goselac [JV2000B J with N-vinyl-2-pyrrolidone and ethylcarpitol acrylic l/-]
After stirring and dissolving, all of the additives described in "1" were added to the solution and stirred. The ink was then 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. The viscosity and thixotropic index were measured using a Bit type viscometer (manufactured by Tokyo Keiki).
It was carried out at 25°C.

Table 3 Example 3 (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 50 μm.
The m screen pattern uses a screen plate with a fine line resolution pattern and a urethane squeegee with a hardness of 60 to create a circuit-formed printed wiring board (a double-sided circuit-type glass plate that has been subjected to a circuit-forming process by punching through-holes or etching). Epoxy-copper thin laminate (hereinafter referred to as "circuited printed wiring board")) was manually screen printed. The results are shown in Table 4.

Table 4 Note: The screen printed glass plate was cured with UV rays under the conditions of Example 4, and the thickness of the cured film was measured. Measurement is by micro gauge.

Example 4 (Curing by UV 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, manufactured by 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 tack-free state, and there were no defects due to wrinkles in the ink due to uncuring.

The pencil hardness of the ink Δ was B1 in 10B, and the pencil hardness was 6B.

Example 5 (Plating treatment) The screen-printed and ultraviolet-cured circuit-formed printed wiring boards A and B of Example 4 were placed in an electrolytic plating solution (an aqueous CN solution with a hydrogen ion concentration of 14) at a plating solution temperature of 30°C. The plate was immersed in water for 2 hours to perform plating treatment. After dipping, the circuit-formed printed wiring board was taken out of the plating bath and washed with water. The obtained primary surface protective coating film of the present invention had sufficient adhesion with no peeling observed. The end of the secondary surface protective coating was turned over with a fingernail and pulled by hand to remove the film. The peeled film had rubber elasticity and was not cut during peeling.

Example 6 (Soldering) Printed wiring boards Δ' and B' with circuits formed by screen printing and UV curing of Example 4 (here, ink A
The printed wiring board A' is screen printed by
, the printed wiring board made with ink B was designated as printed wiring board B')
was immersed for 5 seconds in a solder bath maintained at 250 t. After dipping, the circuit-formed printed wiring board was taken out from the solder bath and cooled to room temperature. The obtained primary surface protective coating film of the present invention had sufficient adhesion with no peeling observed. The end of the secondary surface protective coating was turned over with a fingernail and pulled by hand to remove the film. The peeled film has rubber elasticity,
The film was not cut during peeling.

(Effects of the Invention) As explained above, the primary surface protective coating film according to the present invention is based on a rubber-like elastic material having ultraviolet ray curability, and is based on a solventless or solvent-free screen ink having screen printing characteristics. manufacture,
Utilizing this, the desired coating is applied onto an inorganic or organic surface by screen printing or a thin film coater, and then cured by irradiation with ultraviolet rays, so the cured thickness is 30μ
Despite its thin film thickness, it has excellent chemical resistance to plating solutions and heat resistance during soldering, as well as excellent removability after processing, and because it uses solvent-free or solvent-free screen ink, it is easy to work with. improve the environment,
Eliminates the need for air conditioning equipment, etc. In addition, because it uses screen printing and UV curability, it is possible to accurately reproduce patterns and perform highly accurate surface treatment.
The effect of making it possible to remove defects such as deformation of the surface-treated material due to heat curing and to shorten the curing time can be obtained.

Proceeding Amendment Written March 3, 1986 Michibe Uga, Commissioner of the Patent Office1, Indication of the case, Patent Application No. 7765, filed in 19882, Name of the invention: Method for forming a temporary surface protective coating film cured by ultraviolet rays 3. Relationship with the case of the person making the amendment Patent applicant Hayakawa Rubber Co., Ltd. 4, agent 1, amend the scope of claims on page 1, line 4 to page 4, line 2 of the specification as follows. .

``2. Claim 1: A method for forming a temporary surface protective film used when selectively surface-treating an inorganic surface by a surface treatment method such as electrolytic plating, electroless plating, or soldering. , a solvent-free or solvent-free screen ink with screen printing properties is created based on a rubber-like elastic material with UV curability, and this is screen printed on the inorganic or organic surface to be coated with the desired coating. Alternatively, a method for forming a temporary surface protective coating film cured by UV rays, characterized in that the temporary surface protective coating film is formed by coating with a thin film coating machine and then curing by irradiating with ultraviolet rays.

2. The rubber-like elastic body having ultraviolet curability has a molecular weight of 1
．． 100 parts by weight of liquid rubber having a hydroxyl group of 000 or more and 10,000 or less, 5 to 190 parts by weight of a diisocyanate compound, 1 to 90 parts by weight of a dihydric alcohol having a molecular weight of 300 or less, and 2 to 2 ethylenically unsaturated monomers having a hydroxyl group.
It is a rubber-based copolymer having ultraviolet curable properties made by homogeneously blending and polymerizing four components consisting of 5 parts by weight, and its main components are of the following formula: (where R is an alkyl group having 1 to 8 carbon atoms, R3 is "I" or CH3, R2 is a diisocyanate residue, R3 is a residue of a dihydric alcohol from which the hydroxyl group has been removed, X is a portion of a diene liquid rubber having a hydroxyl group from which the hydroxyl group has been removed, p is 1 to 4, n
The method for forming a temporary surface protective coating film cured by ultraviolet light according to claim 1, wherein m is 1 to 12, and m is 1 < m × 3.

3. The rubber-like elastic body having ultraviolet curable property has flexible physical properties of the coating film after being cured by ultraviolet rays, and has a pencil hardness value of B to 6.
2. The method for forming a UV-cured temporary surface protective coating film according to claim 1, wherein B is polyether-based urethane acrylate or polyester-based urethane acrylate.

4. The composition of the solvent-free or solvent-free screen ink having screen printing properties is based on 100 parts by weight of a rubber-like elastic material having ultraviolet ray curability, and 10 to 200 parts by weight of ethylenically unsaturated monomer as the main component. In addition, 0.1 to 10 parts by weight of photosensitizer, 0.01 to 10 parts by weight of thermal polymerization inhibitor, 0.001 to 10 parts by weight of colorant, 0.1 to 10 parts by weight of antifoaming agent, and thickener. agent 0.5-20
0 parts by weight, 0.1 to 10 parts by weight of a release agent, 5 to 20 parts by weight of a general-purpose rubber, 5 to 50 parts by weight of a liquid rubber, and 5 to 20 parts by weight of an organic solvent. The method for forming a temporary surface protective coating film cured by ultraviolet rays according to claim 1, which is an ink composition prepared by adding and blending at least one species to impart screen printing properties. 2. "Electroplating" on page 4, line 11 of the specification is corrected to "electrolytic plating."

3. On page 6, line 7, "suitable for cleaning process" is corrected to "subject to cleaning process."

4. In the same page 13, line 11, "one or two" is corrected to "one or more".

5. In the same page 3, line 16, add the following between "the shaped elastic body is" and "ultraviolet hardness".

[Molecule II, 100 parts by weight of liquid rubber having 000 to 10,000 hydroxyl groups, 5 to 190 parts by weight of a diisocyanate compound, 1 to 90 parts by weight of dihydric alcohol having a molecular weight of 300 or less, and an ethylenically unsaturated monomer having hydroxyl groups. A rubber-based copolymer with ultraviolet curable properties made by uniformly mixing and reacting 2 to 25 parts by weight of polymers, the main component of which is (I).
Rubber-based urethane acrylate represented by the formula 6, page 21, line 17, ``There is an acrylate.''
Add the following after.

"For example, as polyether urethane acrylates, Aloex M-1100, Aloex M-1
200 (manufactured by Toagosei Kagaku Kogyo ■, product name), Go * Rack [lV2O static B, Go Serak tlV30
00B (manufactured by Nippon Gosei Kagaku Kogyo ■, product name), polyester urethane acrylate toshiteha,
There are PIJ-122, PHI-124 (trade name, manufactured by Arayo Chemical Industry Co., Ltd.), and the like.

7. The following correction is made to page 22, line 15.

``Thermoelectricity with a saturated monomer and a photosensitizer as essential components'' 8, 18 hours in line 16 of page 28 is corrected to ``3 hours.''

9. Correct "output" in the first line of page 30 to "input".

10. Correct [Ar D) 70J in the 5th line of page 30 to "Arm) 70".

11, page 30, lines 12-13 [Goselac I
[Correct JV2000B J to Aroex M-1100j.

12, page 31, page 5, table 2)
2" is corrected to "Aroex M-1100J.

13. In the fifth line from the bottom of page 31, "1) Product name manufactured by Toshi ■" is corrected to 11) Product name manufactured by Toagosei Chemical Industry ■.

14, page 32, lines 6-7 [Goselac Uv2
000BJ is corrected to [Aroex M-1100J.

15. In the same page 33, line 10, "emulsion thickness 50 μm scratch" is corrected to "emulsion thickness 50 μm 1 scratch".

16, on page 33, line 16, “manual” is replaced with “
(referred to as "manual")).

17. Correct "output 3kw J" in line 16 of page 34 to "input 3IVJ.

18, "Wiring boards Δ and B" in the 7th line of page 35 are printed wiring boards A' and B' (here, the one screen printed with ink Δ is called printed wiring board A', and the one printed with ink B is called printed wiring board (The board B' was used as the board B'.)

Claims (1)

[Claims] 1. In a method for forming a temporary surface protective film used when selectively surface-treating an inorganic surface by surface treatment methods such as electroplating, electroless plating, and soldering, an ultraviolet curable Based on a rubber-like elastic body with
A solvent-free or solvent-free screen ink having screen printing properties is prepared, and this is applied by screen printing or a thin film coating machine onto the inorganic or organic surface to be coated with the desired coating.
A method for forming an ultraviolet-cured temporary surface protection coating film, which comprises forming a temporary surface protection coating film by subsequently curing the film by irradiating it with ultraviolet rays. 2. The rubber-like elastic body having ultraviolet curable properties has a molecular weight of 1,
100 parts by weight of a liquid rubber having a hydroxyl group of 000 to 10,000, 5 to 190 parts by weight of a diisocyanate compound, 1 to 90 parts by weight of a dihydric alcohol having a molecular weight of 300 or less, and 2 to 2 to 100 ethylenically unsaturated monomers having a hydroxyl group. 25
It is a rubber-based copolymer with ultraviolet curable properties made by homogeneously blending and polymerizing four components consisting of parts by weight, and its main components are as follows; ▲There are mathematical formulas, chemical formulas, tables, etc.▼... ) (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,
is a portion of a diene-based liquid rubber having a hydroxyl group excluding the hydroxyl group, l is 1 to 4, n is 1 to 12, and m is 1<m<3. A method for forming a temporary surface protective coating film cured by UV rays. 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 to 6B.
The method for forming a temporary surface protective coating film cured by ultraviolet rays according to claim 1, which is a polyether-based urethane acrylate or a polyester-based urethane acrylate. 4. The composition of the solvent-less or solvent-free screen ink having screen printing properties is based on 100 parts by weight of a rubber-like elastic material having ultraviolet ray curability, and 10 to 200 parts by weight of ethylenically unsaturated monomer as the main component. In addition, 0.1 to 10 parts by weight of photosensitizer, 0.01 to 10 parts by weight of thermal polymerization inhibitor, 0.001 to 10 parts by weight of colorant, 0.1 to 10 parts by weight of antifoaming agent, and thickener. agent 0.5-200
Parts by weight, release agent 0.1 to 10 parts by weight, general-purpose rubber 5
~20 parts by weight, 5 to 50 parts by weight of liquid rubber, and 5 parts by weight of organic solvent
The ultraviolet-cured temporary according to claim 1, which is an ink composition prepared by adding and blending one or more selected from the group of ~20 parts by weight to impart screen printing properties. Method for forming a surface protective coating.