JP5478291B2 - Crosslinkable composition for producing screen printing mask with resin - Google Patents

Description

  The present invention relates to a crosslinkable resin composition for use in the production of a resin-coated screen printing mask.

  With recent miniaturization and multi-functionalization of electronic devices, the density of printed wiring boards and the miniaturization of wiring patterns have been promoted, and high-density mounting of electronic components on printed wiring boards has been widely performed. Yes. In high density mounting of electronic components on this printed wiring board, cream solder is printed to mount the electronic components on the surface of the printed wiring board, and the electronic components are mounted on the solder terminals, and then heated in a reflow furnace for soldering. To do. As a method for printing cream solder, a screen printing process is widely used. In general, screen printing is performed by setting a screen printing mask having a pattern-shaped opening formed on an upper surface of a substrate to be printed, supplying paste material such as cream solder on the screen printing mask, and using a squeegee. In this method, the paste material is transferred and printed in a pattern through the opening by scraping.

  When cream solder is printed on the surface of the substrate to be printed using a screen printing mask and solder terminals for mounting electronic components are formed, if the pattern becomes dense and high definition, the cream solder can be removed from the screen printing mask. Cause deterioration. In recent years, there has been an increasing trend toward lead-free cream solder materials due to environmental problems, and lead-free solder containing no lead has been used as part of the countermeasure. Lead-free cream solder tends to be inferior in transferability compared to conventional cream solder. Deterioration of transferability, specifically, deterioration of the ability to remove cream solder from a screen printing mask causes defects such as protrusions, chipping, cracks, and removal of solder terminals. In addition, bleeding of cream solder may occur due to deterioration of the adhesion between the substrate to be printed and the screen printing mask, both of which have been a major cause of yield reduction.

  In order to solve such a problem, a screen printing mask with resin in which a silicone elastomer is laminated as a resin layer on a metal mask and an opening is provided by a laser method has been proposed (for example, see Patent Document 1). The presence of the resin layer improves adhesion to the printed circuit board and can achieve screen printing that does not cause cream solder bleeding, but the resin layer adheres to the printed circuit board and raises the screen printing mask with resin. In addition, there is a problem that the substrate to be printed is lifted and separation of the plate cannot be easily performed. Also, if the metal mask and the resin layer are simultaneously opened by the laser method, a large amount of heat is generated from the metal mask, which may cause deformation or modification of the resin layer. Both the metal mask and the resin layer are opened well. There is also a problem that it is difficult to determine the laser irradiation conditions for this purpose.

  In addition, a technique has been proposed in which a photosensitive resin layer is formed after a metal mask is manufactured, and the photosensitive resin layer is opened in accordance with the opening position of the metal mask by a photolithography method (see, for example, Patent Document 2). However, when the printed pattern has a high density and a high definition, there is a problem in the photolithographic method that it is difficult to accurately form the opening of the photosensitive resin layer without being displaced at the opening position of the metal mask.

  On the other hand, a method for manufacturing a resin-coated screen printing mask in which a resin layer having an opening is provided at substantially the same position as the opening on one main surface of the screen printing mask having an opening, A step of coating a resin layer on one main surface of the printing mask by laminating, and a resin layer by supplying a resin layer removing liquid from the main surface opposite to the side on which the resin layer of the screen printing mask is provided A method of producing a screen-printed mask with resin including a step of forming an opening in is proposed (for example, see Patent Document 3). Depending on this method, there is an effect that no displacement occurs between the opening of the screen printing mask and the opening of the resin layer, and there is no collective opening by the laser method, so that an effect that the deformation of the resin layer does not occur is obtained. It is done. In addition, since a screen printing mask having an opening portion can be produced under optimum manufacturing conditions, a resin layer can be formed on a screen printing mask having good inner wall surface smoothness and opening shape dimensional accuracy, etc. The effect that the board thickness of a printing mask and the thickness of a resin layer can be set freely is also acquired. Patent Document 3 contains a crosslinkable composition containing a binder polymer containing a carboxyl group, a photopolymerizable compound having at least one polymerizable ethylenically unsaturated group in the molecule, and a photopolymerization initiator. A resin layer has been proposed, and after the opening is formed, the resin layer is subjected to a resistance treatment by photocrosslinking by an ultraviolet irradiation treatment and a heat treatment.

  In general, when a screen printing mask is repeatedly used, a cream solder residue is generated at the opening of the screen printing mask or the printed substrate contact surface. At this time, it is necessary to perform ultrasonic cleaning with an organic solvent such as alcohols or glycols, or to wipe off with a waste or cleaning paper impregnated with an organic solvent. For this reason, it is necessary to form a solvent-resistant resin layer that does not swell in an organic solvent and can withstand rubbing of the waste.

  In order to produce such a resin layer having resistance to organic solvents, it can be solved by forming a resin layer having a high crosslinking density by increasing the blending amount of the polyfunctional monomer. However, on the other hand, there has been a problem that the resin layer becomes hard. When the resin layer is hard, the followability of the resin layer to the symbol marks on the substrate and the unevenness of the solder resist deteriorates, and even if printing is performed with a strong printing pressure, cream solder bleeding occurs. In the resin layer containing the crosslinkable composition of Patent Document 3, it may be difficult to achieve both the organic solvent resistance and the flexibility of the resin.

JP 2004-31867 A Japanese Patent No. 3017752 International Publication No. 2007/117040 Pamphlet

  The subject of this invention is providing the crosslinkable composition used for preparation of the screen-printing mask with resin which balances solvent resistance and a softness | flexibility.

  As a result of intensive studies to solve the above problems, the present inventors have formed a resin layer and a masking layer containing a crosslinkable composition on one main surface of a screen printing mask having an opening. And a step of forming an opening in the resin layer by supplying a resin layer removal liquid from the main surface opposite to the side on which the resin layer is provided of the screen printing mask. A crosslinkable composition used, at least (A) a binder polymer containing a carboxyl group, (B) a photopolymerization initiator, (C) a urethane (meth) acrylate compound, and (D) a polyfunctional blocked isocyanate compound It has been found that the above-mentioned problems can be solved by a crosslinkable composition for producing a screen-printed mask with resin, characterized by comprising

  Since the crosslinkable composition for producing a screen-printed mask with resin of the present invention contains the component (B) and the component (C), a cured film is formed by performing photocrosslinking after forming the opening. The Furthermore, by performing the heat treatment, a strong bond is formed by thermal crosslinking between the isocyanate group generated from the blocked isocyanate group in the component (D) and the carboxyl group in the component (A). Since an excellent cured film can be obtained, it is possible to produce a screen-printed mask with a resin that is less likely to cause a reduction in the thickness of the resin layer even when rubbed with a waste impregnated with an organic solvent. Moreover, since it contains (C) component, even if it is a cured film, a flexible resin layer can be formed. Moreover, since (A) component is contained, it is possible to use alkaline aqueous solution for a resin layer removal liquid, and can form an opening part in a resin layer.

Sectional drawing showing 1 process of the method of producing the screen printing mask with resin concerning this invention. Sectional drawing showing 1 process of the method of producing the screen printing mask with resin concerning this invention. Sectional drawing showing 1 process of the method of producing the screen printing mask with resin concerning this invention. Sectional drawing showing 1 process of the method of producing the screen printing mask with resin concerning this invention.

  Hereinafter, the crosslinkable composition for producing a screen-printed mask with resin of the present invention (hereinafter referred to as “crosslinkable composition of the present invention”) will be described in detail. A printed wiring board will be described as an example of a substrate to be printed and cream solder will be described as an example of a paste material. However, the present invention is not limited to this example unless it is contrary to the spirit of the present invention.

  With reference to the drawings, a method for producing a screen-printed mask with resin according to the present invention will be described. A resin layer 4 and a masking layer 3 are formed by lamination on one main surface (hereinafter referred to as “first surface”) of a screen printing mask 1 (FIG. 1) having an opening 2 so as to close the opening. (FIG. 2). Next, a resin layer removing liquid is supplied from the other main surface (hereinafter referred to as “second surface”). The resin layer removing liquid passes through the opening 2 and reaches the resin layer 4 on the first surface, and removes the resin layer 4 on the opening 2 (FIG. 3). The masking layer 3 is made of a component that is insoluble in the resin layer removing liquid. Therefore, the resin layer removing liquid can be accurately and selectively removed on the opening 2 of the resin layer 4. After removing the resin layer 4 on the opening 2, the masking layer 3 is removed (FIG. 4), so that a screen-printed mask with resin from which the opening 2 of the resin layer 4 is removed can be produced.

  The resin layer contains the crosslinkable composition of the present invention. The crosslinkable composition of the present invention contains at least (A) a binder polymer containing a carboxyl group, (B) a photopolymerization initiator, (C) a urethane (meth) acrylate compound, and (D) a polyfunctional blocked isocyanate compound. Do it.

  The component (A) is not particularly limited as long as it is mixed with the component (B), the component (C), and the component (D). Examples thereof include organic polymers such as acrylic resins, epoxy resins, urethane resins, amide resins, amide epoxy resins, and alkyd resins. These may be used individually by 1 type and may be used in combination of 2 or more type.

  When an aqueous alkali solution is used for the resin layer removal solution, it is preferable to use an acrylic resin because of its high solubility in the resin layer removal solution. As the acrylic resin, a monomer having (meth) acrylate as a main component and having an ethylenically unsaturated carboxylic acid and other copolymerizable ethylenically unsaturated groups (hereinafter referred to as “polymerizable monomer”). May be any acrylic polymer obtained by copolymerization.

  Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, 3-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (dimethylamino) ethyl Meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate.

  Monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid are preferably used as the ethylenically unsaturated carboxylic acid, and dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and anhydrides and half esters thereof. It can also be used. Among these, acrylic acid and methacrylic acid are particularly preferable.

  Examples of the other polymerizable monomers include styrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-methoxystyrene, p-ethoxystyrene, p-chlorostyrene, p-bromostyrene, (Meth) acrylonitrile, (meth) acrylamide, diacetone acrylamide, vinyl toluene, vinyl acetate, vinyl n-butyl ether and the like can be mentioned.

  In the component (A) according to the present invention, combinations of two or more types include, for example, a combination of two or more types of polymers having different copolymerization components, or two or more types of polymers having different mass average molecular weights. And combinations of two or more binder polymers having different dispersities (mass average molecular weight / number average molecular weight).

  The acid value of component (A) is preferably 30 to 500 mgKOH / g, and more preferably 100 to 300 mgKOH / g. When an alkaline aqueous solution is used as the resin layer removing solution, the acid value tends to be longer if the acid value is less than 30 mg KOH / g, whereas if it exceeds 500 mg KOH / g, the resin layer on the mask for screen printing is used. May stick.

  Moreover, it is preferable that it is 10,000-200,000, and, as for the mass mean molecular weight of a component (A), it is more preferable that it is 10,000-150,000. If the weight average molecular weight is less than 10,000, it may be difficult to form the crosslinkable composition of the present invention in a film state, whereas if it exceeds 200,000, the solubility in the resin layer removing solution deteriorates. Tend.

  Examples of the component (B) according to the present invention include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy -4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone Aromatic ketone such as -1, 2-ethylanthraquinone, phenanthrenequinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3- Diphenylanthraquinone, 1-chloroanthraquinone, -Quinones such as methyl anthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone; benzoin methyl ether, benzoin ethyl ether, benzoin phenyl Benzoin ether compounds such as ether; benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o- Chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenyl Imidazole dimer, 2- (p- 2,4,5-triarylimidazole dimers such as toxiphenyl) -4,5-diphenylimidazole dimer; acridines such as 9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane Derivatives: N-phenylglycine, N-phenylglycine derivatives, coumarin compounds and the like. The substituents of the aryl groups of two 2,4,5-triarylimidazoles in the 2,4,5-triarylimidazole dimer may give the same and symmetrical compounds, but differently Asymmetric compounds may be provided. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid. These may be used alone or in combination of two or more.

  The component (C) according to the present invention refers to a reaction product of a compound having a terminal isocyanate group obtained by reacting a diol compound and a diisocyanate compound and a (meth) acrylate compound having a hydroxyl group. Examples of the diol compound include polyesters having a hydroxyl group at the terminal, polyethers, and the like. Polyesters obtained by ring-opening polymerization of lactones, polycarbonates, ethylene glycol, propylene glycol, diethylene glycol, Examples thereof include polyesters obtained by condensation reaction of alkylene glycol such as triethylene glycol and dipropylene glycol and dicarboxylic acid such as maleic acid, fumaric acid, glutaric acid and adipic acid. Specific examples of the lactones include δ-valerolactan, ε-caprolactone, β-propiolactone, α-methyl-β-propiolactone, β-methyl-β-propiolactone, α, α-dimethyl- β-propiolactone, β, β-dimethyl-β-propiolactone and the like can be mentioned. Specific examples of the polycarbonates include reaction products of diols such as bisphenol A, hydroquinone, and dihydroxycyclohexanone with carbonyl compounds such as diphenyl carbonate, phosgene, and succinic anhydride. Specific examples of the polyethers include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polypentamethylene glycol.

  Specific examples of the diisocyanate compound that reacts with the diol compound include dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, 2,2-dimethylpentane-1,5-diisocyanate. , Octamethylene diisocyanate, 2,5-dimethylhexane-1,6-diisocyanate, 2,2,4-trimethylpentane-1,5-diisocyanate, nanomethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, decamethylene diisocyanate And an aliphatic or alicyclic diisocyanate compound such as isophorone diisocyanate, and the compound alone or Mixtures of more than can be used.

  Furthermore, as the (meth) acrylate compound having a hydroxyl group, specifically, hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) An acrylate etc. can be mentioned, The single or 2 types or more can be mixed and used.

  Component (C) according to the present invention may contain a carboxyl group. By containing a carboxyl group, the solubility in the resin layer removal liquid tends to be improved. The component (C) containing a carboxyl group is first reacted with a diisocyanate compound and a diol compound having a carboxyl group so that isocyanate groups remain at both ends, and then the terminal isocyanate group of the reaction product is reacted with a hydroxyl group. It can be obtained by reacting a (meth) acrylate compound having

  As for the glass transition point of the component (C) concerning this invention, -10 degrees C or less is preferable. When this glass transition point exceeds -10 ° C., the flexibility of the crosslinkable composition is lost, so that cream solder bleeding may occur.

  The component (D) according to the present invention is a compound that is obtained by reacting a blocking agent with the isocyanate group of a polyfunctional isocyanate compound, and is a stable compound at room temperature. Cleavage generates isocyanate groups. As blocking agents, phenols such as phenol, cresol, p-ethylphenol, pt-butylphenol, alcohols such as ethanol, butanol, ethylene glycol, methyl cellosolve, benzyl alcohol, diethyl malonate, ethyl acetoacetate, etc. Active methylenes, acid amides such as acetanilide, acetamide, other imides, amines, imidazoles, pyrazoles, ureas, carbamic acids, imines, holadaldoxime, acetoaldoxime, cyclohexanone oxime, etc. There are oxime, mercaptan, sodium bisulfite, sulfites such as potassium bisulfite, and lactams.

  Examples of the polyfunctional isocyanate compound include 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, xylylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and 4,4′-methylene bis. (Cyclohexyl isocyanate), trimethylhexanemethylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, lysine diisocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3- (isocyanatomethyl) cyclohexane , Dimer acid diisocyanates and their adducts, biurets, isocyanurates, etc. Ma and the like.

  You may make the crosslinkable composition of this invention contain components other than the said component (A)-(D) as needed. Such components include photopolymerizable monomers, thermal polymerization inhibitors, plasticizers, colorants (dyes, pigments), photochromic agents, thermochromic inhibitors, fillers, antifoaming agents, flame retardants, stable Agents, adhesion-imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, thermosetting agents, surface tension modifiers, water and oil repellents, and the like, each of 0.01 to 20 mass. % Can be contained. These components can be used individually by 1 type or in combination of 2 or more types.

  The photopolymerizable monomer is a compound having at least one polymerizable ethylenically unsaturated group in the molecule other than the component (C). For example, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid; a bisphenol A (meth) acrylate compound; obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid Compound; Nonylphenoxypolyethyleneoxyacrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o-phthalate, etc. (Meth) acrylic acid alkyl ester, EO, PO-modified nonylphenyl (meth) acrylate, and the like. Here, EO and PO represent ethylene oxide and propylene oxide, the EO-modified compound has a block structure of ethylene oxide group, and the PO-modified compound has a block structure of propylene oxide group. Is. These photopolymerizable compounds can be used alone or in combination of two or more.

  Further, as the photopolymerizable monomer, a compound having three or more polymerizable ethylenically unsaturated groups in the molecule may be used. Examples of the photopolymerizable compound having three or more polymerizable ethylenically unsaturated groups in the molecule include trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and pentaerythritol tri (meth). Examples include those containing at least one of acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and trimethylolpropane triglycidyl ether tri (meth) acrylate. It is done.

  The crosslinkable composition of the present invention may be prepared by using alcohols such as methanol, ethanol, n-propanol, 2-butanol and n-hexanol; ketones such as acetone and 2-butanone; ethyl acetate, butyl acetate, Esters such as acetic acid-n-amyl, methyl sulfate, ethyl propionate, dimethyl phthalate, ethyl benzoate, aromatic hydrocarbons such as toluene, xylene, benzene, ethylbenzene; tetrahydrofuran, diethyl ether, ethylene glycol monomethyl ether, Ethers such as ethylene glycol monoethyl ether and 1-methoxy-2-propanol; solvents such as N, N-dimethylformamide and dimethyl sulfoxide or mixed solvents thereof may be contained.

  In the crosslinkable composition of the present invention, the blending amount of the component (A) is preferably 10 to 50% by mass with respect to the total amount of the component (A), the component (C) and the component (D). More preferably, it is 40 mass%. If the blending amount of the component (A) is less than 10% by mass, the film property may be deteriorated or the opening may not be possible. When the compounding amount of the component (A) exceeds 50% by mass, the hardness of the coating may become hard.

  The blending amount of component (B) is preferably 0.1 to 10% by mass, and 0.2 to 5% by mass with respect to the total amount of component (A), component (C) and component (D). It is more preferable. When the blending amount of the component (B) is less than 0.1% by mass, the photopolymerizability may be insufficient. On the other hand, when it exceeds 10% by mass, absorption occurs on the surface of the crosslinkable composition upon exposure. In some cases, the photo-crosslinking inside the resin layer becomes insufficient.

  The compounding amount of the component (C) is preferably 30 to 70% by mass and more preferably 40 to 60% by mass with respect to the total amount of the component (A), the component (C) and the component (D). . When the blending amount of the component (C) is less than 30% by mass, the softness of the resin may be insufficient. On the other hand, when it exceeds 70% by mass, the tackiness of the film surface may be remarkable.

  The amount of component (D) is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total amount of component (A), component (C) and component (D). When the blending amount of component (D) is less than 5% by mass, the solvent resistance after heating may be insufficient, while when it exceeds 40% by mass, the hardness of the coating may be hardened. Also, the photosensitivity may be insufficient.

  In the method for producing a screen-printed mask with resin according to the present invention, a process of removing the masking layer 3 after supplying the resin layer removing liquid from the second surface and removing the resin layer 4 on the opening 2 (FIG. 4). Next, it is necessary to subject the crosslinking composition of the present invention to a crosslinking reaction by ultraviolet irradiation treatment and heat treatment. If only the UV irradiation treatment is used, sufficient mechanical strength and solvent resistance cannot be obtained. If only the heat treatment is used, the edge of the opening will be rounded, thereby causing cream solder bleeding. And it becomes a problem. When the heat treatment is performed first, and then the ultraviolet irradiation treatment is performed, the phenomenon that the edge of the opening is rounded occurs, and first, after holding the shape of the resin layer by the ultraviolet irradiation treatment, It is necessary to heat-treat.

In the ultraviolet irradiation treatment, active light is irradiated using a light source such as a high-pressure mercury lamp or an ultra-high pressure mercury lamp. Amount is preferably 0.5~20J / cm ^2, more preferably 1~10J / cm ^2. When the amount of light is less than 0.5 J / cm ² , unreacted unsaturated groups remain in the photopolymerizable compound in the resin layer, and sufficient photocrosslinking may not be performed. On the other hand, if it exceeds 20 J / cm ² , the photocrosslinking reaction in the resin layer reaches saturation, so that no more light is required. The heat treatment is preferably at or above the temperature at which the blocking agent used is cleaved. The heating temperature is preferably 90 to 250 ° C, more preferably 140 to 200 ° C. If it is less than 90 ° C., the progress of the crosslinking reaction may be slow, and if it exceeds 250 ° C., decomposition of other components may occur. The heat treatment is preferably performed for 10 to 90 minutes.

  The thickness of the resin layer of the resin-coated screen printing mask according to the present invention is preferably 1 to 100 μm, and more preferably 5 to 50 μm. The thickness of the resin layer is determined in combination with a predetermined thickness of the screen printing mask so that an appropriate amount of the paste material is printed with respect to the transfer amount of the paste material to be printed. When the thickness of the resin layer is too large, the opening tends to be insufficient. On the other hand, if it is too thin, not only the adhesion between the screen printing mask and the resin layer will be reduced, but the resin layer will not be able to absorb fine irregularities on the surface of the substrate to be printed, Adhesion decreases, bleeding occurs, and may cause a bridge between transfer patterns.

  As the masking layer according to the present invention, a resin or metal that is insoluble or hardly soluble in the resin layer removing solution can be used. Examples of the resin include acrylic resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetal resin such as polyvinyl butyral, polystyrene, polyethylene, polypropylene and its chloride, polyester resin such as polyethylene terephthalate and polyethylene isophthalate, polyamide Resins such as resins, vinyl-modified alkyd resins, phenol resins, xylene resins, polyimide resins, gelatin, and cellulose ester derivatives such as carboxymethyl cellulose can be used. From the viewpoint of versatility, a polyester resin, a polyimide resin, or the like can be preferably used. Copper, aluminum, etc. can be used as a metal. As the masking layer, it is more preferable to use a resin rather than a metal in terms of simplicity and in-plane uniformity. If the masking layer is formed in a film shape and integrated with the resin layer on the screen printing mask, it is preferable because the resin layer and the masking layer can be formed easily and stably in the process.

  As a method for integrally forming the resin layer and the masking layer according to the present invention, a resin layer comprising a resin or a film of a metal or the like that is used as a masking layer and a crosslinkable composition for producing a screen-printed mask with resin in advance. And a method of thermocompression bonding to a screen printing mask with a laminator can be suitably used.

  The resin layer removing liquid according to the present invention is a liquid that can dissolve or disperse the crosslinkable composition (resin layer) for producing a screen-printed mask with resin, and a liquid that matches the composition of the resin layer to be used. With the resin layer removing liquid, the resin layer in the opening is removed, and a region where no resin layer is present is formed in the opening. Even if the resin layer removal solution is a solution that does not dissolve the masking layer, or a solution that dissolves the masking layer, the masking layer swells or changes its shape under the condition that the resin layer is dissolved by an appropriate amount. Use a liquid that does not get wet. In addition, a resin layer removing liquid that does not cause dissolution, swelling, shape change or the like is used for the screen printing mask. In general, an alkaline aqueous solution is usefully used. Examples of the alkaline aqueous solution include, for example, an aqueous solution of an inorganic basic compound such as alkali metal silicate, alkali metal hydroxide, phosphoric acid or alkali metal carbonate, phosphoric acid or ammonium carbonate, ethanolamine, ethylenediamine, propanediamine, An aqueous solution of an organic basic compound such as triethylenetetramine or morpholine can be used. These aqueous solutions need to be adjusted in concentration, temperature, spray pressure and the like in order to control solubility in the resin layer. Any method may be used for supplying the resin layer removing liquid as long as it can be supplied from the surface opposite to the surface having the masking layer so that the resin layer removing liquid is in contact with the resin layer through the opening. A dip treatment device, a double-sided shower spray device, a single-sided shower spray device, or the like can be used. The removal of the resin layer can be quickly stopped by washing with water or acid treatment following the treatment with the resin layer removing solution.

  The screen-printed mask with resin of the present invention has an opening for transferring and printing an appropriate amount of paste material, but there are various shapes. For example, a quadrangle such as a circle, an ellipse, a square, a rectangle, a rhombus and a trapezoid, a polygon such as a hexagon and an octagon, and an indefinite shape such as a gourd and a dumbbell. In addition, the size of the opening is several hundred μm to several tens of mm in general surface mounting, and the size is 30 to 300 μm and the pitch interval is 50 to 500 μm in high-density mounting. Further, the opening of the screen printing mask may have a taper.

  The screen printing mask with resin according to the present invention can be a screen printing mask produced by any method as long as the paste material is placed on one side and the paste material can be transferred onto the pattern by scraping with a squeegee. Can be used. Metal mask produced by additive method, metal mask produced by laser method, metal mask produced by etching method, printing mask having screen printing masking layer with openings on mesh layer (emulsion type screen printing mask, Solid mask, suspend mask).

  As a material for the screen printing mask used for the screen printing mask with resin according to the present invention, a metal plate mainly composed of nickel, copper, chromium, zinc, iron, or the like, an alloy, a stainless steel plate or the like is preferable. The screen printing mask has a thickness of 30 to 400 μm, and may be a single layer or a laminate of the metal or alloy. In the case of an emulsion type screen printing mask (mesh mask), there are a metal mesh in which metal wires are made into a plain weave and a resin mesh in which resin wires are made into a plain weave, depending on the type of mesh material. There is also a non-woven mesh, which is formed by depositing a metal such as nickel into a mesh by an additive method (electroforming method). Further, a mesh called a plating screen is also used in which various plain weave meshes are subjected to metal plating and the intersections are fixed to improve the dimensional stability.

  The screen-printed mask with resin according to the present invention can be used for any screen printing, but is usually attached to a rigid frame. For example, a mesh is first attached to a rigid metal frame, and the outer periphery of the surface on the opposite side of the resin layer of the produced screen print mask with resin is attached to the mesh with an adhesive. paste. Subsequently, a screen-printed mask with resin with a frame can be produced by cutting off the inner mesh other than the bonded portion.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example.

(Examples 1-7, Comparative Examples 1-3)
Each component shown in Table 1 was mixed, and the coating liquid for crosslinkable compositions for resin-made screen printing mask preparation was obtained. In addition, the unit of each component compounding amount in Table 1 represents a mass part. The obtained coating liquid was applied onto a polyethylene terephthalate (PET) film (trade name: R310, 25 μm thickness, manufactured by Mitsubishi Chemical Res. Co., Ltd., used as a masking layer) using a wire bar, and 80 ° C. And dried for 8 minutes, the solvent component was skipped, and the crosslinkable composition for preparing screen print masks with resin of Examples 1 to 7 and Comparative Examples 1 to 3 (dry film thickness: 20 μm) was contained on one side of the PET film. Thus obtained resin layer was obtained.

In Table 1, each component is as follows.
Component (A-1): a copolymer resin obtained by copolymerizing methyl methacrylate / n-butyl acrylate / methacrylic acid at a mass ratio of 58/15/27 (30% by mass solution using 1-methoxy-2-propanol as a solvent, Acid value 176 mg KOH / g, mass average molecular weight 70000),
Component (A-2): cellulose acetate phthalate (manufactured by Wako Pure Chemical Industries, Ltd., 30% by mass solution using methyl ethyl ketone as a solvent)
(B-1) 2- (2′-chlorophenyl) -4,5-diphenylimidazole dimer (B-2) 4,4′-bis (diethylamino) benzophenone (C-1) KRM7222 (trade name, Daicel Cytec Co., Ltd., 80% solution with ethyl acetate as solvent)
(C-2) KRM8296 (trade name, manufactured by Daicel-Cytec)
(C-3) EBECRYL210 (trade name, manufactured by Daicel Cytec Co., Ltd.)
(C-4) Purple light UV-2000B (trade name, manufactured by Nippon Synthetic Chemical Co., Ltd.)
(C-5) Purple light UV-3000B (trade name, manufactured by Nippon Synthetic Chemical Co., Ltd.)
(D-1) Sumidur BL3175 (trade name, manufactured by Sumika Bayer Urethane Co., Ltd., base: 1,6-hexamethylene diisocyanate, blocking agent: methyl ethyl ketone oxime, solid content 75%)
(D-2) Death Module BL1100 (trade name, manufactured by Sumika Bayer Urethane Co., Ltd., base: 2,6-tolylene diisocyanate, blocking agent: ε-caprolactam)
(D-3) Dismotherm 2170 (trade name, manufactured by Sumika Bayer Urethane Co., Ltd., base: 4,4'-diphenylmethane diisocyanate, blocking agent: active methylene, solid content 70%)
BPE-500: 2,2′-bis- (4-methacryloxypentaethoxyphenyl) propane (manufactured by Shin-Nakamura Chemical Co., Ltd.)
TMP-A: Trimethylolpropane triacrylate (manufactured by Kyoeisha Chemical Co., Ltd.)

  Next, a large number of openings were formed on a 100 μm thick stainless steel plate (SUS304) with a YAG laser to produce a screen printing mask with an area of 400 × 480 mm. Examples 1 to 7 and Comparative Example 1 obtained above were used. A resin layer containing the crosslinkable composition for preparing a screen-printing mask with resin of 3 to 3 was thermocompression bonded to the first surface of the screen-printing mask at 100 ° C. to provide a resin layer and a masking layer.

  Next, using a resin layer removing solution of 10% by mass sodium carbonate aqueous solution (30 ° C.), a shower spray is applied from the second surface side of the screen printing mask to remove the resin layer on the opening on the first surface. The masking layer was removed after washing with water. When the openings were observed at 10 locations in the plane using an optical microscope, no resin layer remained and good openings could be implemented. Furthermore, the resin layer opening was not displaced over the entire surface, and a resin layer having a thickness of 20 μm was formed.

Next, using a high pressure mercury lamp light source device for baking having a suction adhesion mechanism (trade name: UNIREC URM300, manufactured by USHIO INC., 12 mW / cm ² ), UV irradiation is performed for 300 seconds to photocrosslink the resin layer. It was. Furthermore, it heat-processed for 90 minutes in 120 degreeC oven, the resin layer was heat-crosslinked, and the screen printing mask with resin was produced.

  The screen printing masks with resin produced in Examples 1 to 7 and Comparative Examples 1 to 3 were set on a printed wiring board placed on a pallet, and cream solder was screen printed with a squeegee. In the case of using the resin-coated screen printing masks of Examples 1 to 7 and Comparative Example 1, the cream solder bleeds little, the cream solder remaining in the opening after printing is small and good printing can be performed, and the initial printability is high. It was confirmed that it was good. When the resin-coated screen printing masks of Comparative Examples 2 and 3 were used, the resin layer was hard and bleeding occurred from the 10th plate.

Next, since it was necessary to scrape the residue of the cream solder generated on the printed substrate contact surface of the resin-coated screen printing mask with a waste dipped in an organic solvent, a wiping test was conducted with a waste dipped in an isopropyl alcohol solvent. went. In the wiping test, a waste cloth (trade name: Nanowiper, manufactured by Mitsubishi Paper Industries Co., Ltd.) was wrapped around a 500 g weight of a cylinder having a cross-sectional area of 28.3 cm ² and impregnated with an appropriate amount of each solvent at 20 mm / sec. Rubbed 200 times. As a result of evaluation by waste coloring, the resin-coated screen printing masks obtained in Examples 1 to 7 and Comparative Example 2 were confirmed to have very good solvent resistance. However, in the screen-printed masks with resins of Comparative Examples 1 and 3, the green color of phthalocyanine green was transferred darkly, and it was confirmed that the solvent resistance was low.

  The resin-coated screen printing mask of the present invention is widely applicable to screen printing applications. For example, as a paste material, a conductive material, an insulating material, a color material, a sealing material, an adhesive material, a resist material, a treatment A drug or the like can be applied to a use for forming a pattern on an arbitrary substrate by screen printing.

1 Screen Print Mask 2 Opening 3 Masking Layer 4 Resin Layer

Claims (1)

  A step of forming a resin layer and a masking layer containing a crosslinkable composition on one main surface of a screen printing mask having an opening, and a main side opposite to the side on which the resin layer of the screen printing mask is provided And a step of forming an opening in the resin layer by supplying a resin layer removing liquid from the surface. A crosslink for producing a screen-printed mask with resin, comprising: a binder polymer to be contained; (B) a photopolymerization initiator; (C) a urethane (meth) acrylate compound; and (D) a polyfunctional blocked isocyanate compound. Sex composition.

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