JP5613172B2 - Flame retardant solder resist composition and flexible wiring board obtained using the same - Google Patents

Description

  The present invention relates to a flame retardant solder resist composition and a flexible wiring board having a film obtained by photocuring the flame retardant solder resist composition.

  Solder resists used for the production of flexible wiring boards are: 1) A type in which a polyimide film called a coverlay film is punched out with a mold matched to a pattern, and then attached using an adhesive. 2) It has flexibility. There is used a type in which an ultraviolet curable solder resist composition for forming a film is applied by screen printing, and 3) a type of a liquid photo solder resist composition for forming a film having flexibility.

  However, since the coverlay film has a problem in the followability with the copper foil that is a circuit portion, a high-precision and high-density pattern cannot be formed. On the other hand, the ultraviolet curable / thermosetting solder resist composition and the liquid photo solder resist composition have poor adhesion to the polyimide of the substrate, and sufficient flexibility cannot be obtained. Furthermore, the solder resist composition has a problem that warpage occurs due to large shrinkage due to thermal curing and cooling shrinkage after curing, and sufficient solder heat resistance cannot be obtained.

  Therefore, in Patent Document 1, in order to provide a cured coating film having excellent flexibility, (A) a photosensitive prepolymer having two or more unsaturated double bonds and one or more carboxyl groups in one molecule. , (B) a photopolymerization initiator, (C) a diluent, (D) an epoxy compound, (E) a polybutadiene having one or more internal epoxide groups in one molecule, and (F) a composition containing polyurethane fine particles. Has been proposed.

  Furthermore, as a composition suitable for film formation that is excellent not only in flexibility but also in adhesion to a base material, folding resistance, low warpage, and solder heat resistance, in Patent Document 2, A) an aromatic ring A thermosetting resin composition containing a carboxyl group-containing urethane resin obtained by using a compound having an isocyanate group that is not directly bonded and (B) a thermosetting compound is disclosed.

  Moreover, in patent document 3, as composition which can suppress generation | occurrence | production of the curvature by heating in a component mounting process and was excellent in the adhesiveness with respect to a base material, and solder heat resistance, (A) carboxyl group containing resin, (B) predetermined group An oxime ester-based photopolymerization initiator having the following structure: (C) a composition developable with a dilute alkaline aqueous solution containing a compound having two or more ethylenically unsaturated groups in the molecule, wherein the carboxyl group-containing resin ( A) A photosensitive resin composition containing 0.1 to 1.5 parts by mass of the oxime ester photopolymerization initiator (B) with respect to 100 parts by mass is disclosed.

  On the other hand, since flexible wiring boards are required to be flame retardant because they are mounted on electronic devices, and in recent years, electronic devices have become smaller and more complicated in internal structure. Folding resistance is required, but the above resin composition needs to be further improved in the above characteristics.

JP 2002-293882 A JP2009-79179 JP 2009-86414 A

  In view of the above circumstances, the object of the present invention is to form a solder resist excellent in flame retardancy, low elasticity, high elongation and folding resistance in addition to adhesion to a substrate, low warpage, and solder heat resistance. The object is to provide a solder resist composition. Furthermore, the objective of this invention is providing the flexible wiring board excellent in the flame retardance and folding resistance obtained by using such a soldering resist composition.

The first aspect of the present invention includes (A) a carboxyl group-containing photosensitive resin, (B) an acrylated urethane resin, (C) a photopolymerization initiator, (D) a diluent, (E) an epoxy compound, and (F). a phosphorus element-containing organic filler a including flame retardant solder resist composition, the (B) acrylated urethane resin, has a 2-4 acryloyl groups in a molecule, the weight average molecular weight of 1500 to 3000 It is a flame-retardant solder resist composition characterized by being.

  A second aspect of the present invention is a flame retardant solder resist composition, wherein the (B) acrylated urethane resin has 2 to 4 acryloyl groups in one molecule. A third aspect is the flame retardant solder resist composition, wherein the weight average molecular weight of the (B) acrylated urethane resin is 1500 to 3000.

  A fourth aspect of the present invention is the flame retardant solder resist composition, wherein the (F) phosphorus element-containing organic filler is a metal salt of phosphinic acid.

  A fifth aspect of the present invention is a flame retardant solder resist composition further comprising (G) a powdered urethane resin, and the sixth aspect of the present invention is the above-mentioned (A) carboxyl The flame retardant solder resist composition is characterized in that the powdered urethane resin (G) is contained in an amount of 10 to 30 parts by mass with respect to 100 parts by mass of the group-containing photosensitive resin.

  A seventh aspect of the present invention is a flexible wiring board having a film obtained by photocuring the flame retardant solder resist composition. The eighth aspect of the present invention is a reflective sheet having a film obtained by further applying a white flame retardant resin composition containing titanium oxide to the flame retardant solder resist composition. .

  According to the 1st aspect of this invention, the flame retardance of a soldering resist film can be improved in a small quantity by containing a phosphorus element containing organic filler as a flame retardant. Moreover, generation | occurrence | production of curvature can be suppressed by containing acrylated urethane resin. Furthermore, by including an acrylated urethane resin, flexibility due to low elasticity can be improved, and a soft solder resist film excellent in stretchability and folding resistance can be formed.

  According to the 2nd aspect of this invention, generation | occurrence | production of a curvature and elasticity can be suppressed more because an acrylated urethane resin has 2-4 acryloyl groups in 1 molecule. According to the third aspect of the present invention, when the weight average molecular weight of the acrylated urethane resin is 1500 to 3000, the extensibility is further improved and a soft solder resist film can be formed. Moreover, since the acrylated urethane resin has 2 to 4 acryloyl groups in one molecule and the weight average molecular weight is 1500 to 3000, the occurrence of warpage is further suppressed, and the extensibility and folding resistance are further improved. To do.

  According to the 4th aspect of this invention, since a phosphorus element containing organic filler is a metal salt of phosphinic acid, it is excellent in solder heat resistance and heat resistance with a metal, and can further improve a flame retardance.

  According to the fifth aspect of the present invention, since the powder urethane resin is further contained, the elasticity can be further suppressed. Moreover, according to the 6th aspect of this invention, by containing 10-30 mass parts of powder urethane resin with respect to 100 mass parts of carboxyl group-containing photosensitive resin, in addition to low elasticity, generation | occurrence | production of curvature is produced. While further suppressing the elongation and folding resistance, a softer solder resist film can be formed.

  According to the seventh aspect of the present invention, since the flexible wiring board is coated with the flame retardant solder resist composition film, the flexible wiring board can have a soft structure excellent in folding resistance. According to the eighth aspect of the present invention, since the surface of the base film is coated with a film of a white flame retardant solder resist composition obtained by further blending titanium oxide with the flame retardant solder resist composition, low warpage A soft reflective sheet with excellent folding resistance can be obtained.

  Next, the flame-retardant solder resist composition according to the embodiment of the present invention will be described. The flame-retardant solder resist composition according to the embodiment of the present invention includes (A) a carboxyl group-containing photosensitive resin, (B) an acrylated urethane resin, (C) a photopolymerization initiator, (D) a diluent, E) An epoxy compound and (F) a phosphorus element-containing organic filler are included, and each of the above components is as follows.

  (A) The carboxyl group-containing photosensitive resin is not particularly limited, and is a photosensitive carboxyl group-containing resin having one or more photosensitive unsaturated double bonds, or a carboxyl having no photosensitive unsaturated double bonds. Any of the group-containing resins can be used. As an example of the component (A), at least a part of the epoxy group of a polyfunctional epoxy resin having two or more epoxy groups in the molecule is reacted with a radically polymerizable unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid. Mention may be made of polybasic acid-modified epoxy (meth) acrylates obtained by obtaining (meth) acrylates and reacting the produced hydroxyl groups with polybasic acids or anhydrides thereof.

  Any polyfunctional epoxy resin may be used as long as it is a bifunctional or higher functional epoxy resin, and there is no particular limitation on the epoxy equivalent, but one having a molecular weight of usually 1000 or less, preferably 100 to 500 is used. Examples of the polyfunctional epoxy resin include biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, rubber modified epoxy resin such as silicone modified epoxy resin, ε-caprolactone modified epoxy resin, bisphenol A type, bisphenol. Phenol type novolak type epoxy resin such as F type, bisphenol AD type, cresol novolac type epoxy resin such as o-cresol novolak type, bisphenol A novolak type epoxy resin, cyclic aliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin, Glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolac type epoxy resin, polyfunctional modified novolac type epoxy resin, phenols and phenolic hydroxyl group Condensate type epoxy resin with an aromatic aldehyde having the like. Moreover, what introduce | transduced halogen atoms, such as Br and Cl, to these resin can also be used. Of these, rubber-modified epoxy resins such as silicone-modified epoxy resins are preferred from the viewpoint of the flexibility of the coating film. These epoxy resins may be used alone or in combination of two or more.

  The radically polymerizable unsaturated monocarboxylic acid to be used is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and the like. At least one of acrylic acid and methacrylic acid (hereinafter referred to as (meth)). Acrylic acid is sometimes preferred.) Acrylic acid is particularly preferred. What reacted (meth) acrylic acid is epoxy (meth) acrylate. There is no restriction | limiting in particular in the reaction method of an epoxy resin and radically polymerizable unsaturated monocarboxylic acid, For example, it can react by heating an epoxy resin and acrylic acid in a suitable diluent.

  The polybasic acid or polybasic acid anhydride reacts with a hydroxyl group generated by the reaction between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid to give the resin a free carboxyl group. The polybasic acid to be used or its anhydride is not particularly limited, and either saturated or unsaturated can be used. Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4- Ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexahydro Examples include phthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and diglycolic acid. Examples of polybasic acid anhydrides include these anhydrides. These compounds may be used alone or in combination of two or more.

  Since the solder resist composition containing the above-described carboxyl group-containing photosensitive resin can form a solder resist film having excellent flexibility, it is advantageous for application to a printed wiring board, particularly a flexible wiring board.

  (B) Acrylic urethane resin should just be urethane acrylate obtained by making acrylic acid which is radically polymerizable unsaturated monocarboxylic acid react with urethane resin, and is not limited to a specific compound. The urethane resin is obtained by reacting a compound having two or more isocyanate groups in one molecule with a polyol compound having two or more hydroxyl groups in one molecule.

  Examples of the compound having two or more isocyanate groups in one molecule include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylene biscyclohexyl isocyanate, trimethylhexamethyl diisocyanate, Examples thereof include diisocyanates such as hexane diisocyanate, hexamethylamine diisocyanate, methylenebiscyclohexyl isocyanate, toluene diisocyanate, 1,2-diphenylethane diisocyanate, 1,3-diphenylpropane diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethyl diisocyanate. These compounds may be used alone or in combination of two or more.

Polyol compounds having two or more hydroxyl groups in one molecule include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1, 5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2-diethyl-1,3- C ₂ -C ₂₂ alkanediols such as propanediol, 3,3-dimethylolheptane, 2-ethyl-2-butyl-1,3-propanediol, 1,12-dodecanediol, 1,18-octadecanediol, 2-butene-1,4-diol, 2,6-dimethyl-1-octene-3,8-dioe Aliphatic diols such as alkene diols; alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2 , 4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy- Aliphatic triols such as 3- (hydroxymethyl) pentane and 2,2-bis (hydroxymethyl) -3-butanol; polyols having four or more hydroxyl groups such as tetramethylolmethane, pentaerythritol, dipentaerythritol and xylitol Can be mentioned. These compounds may be used alone or in combination of two or more.

  Examples of commercially available acrylated urethane resins include “purple light UV-1400B”, “purple light UV-1700B”, “purple light UV-6300B”, and “purple light UV-7510B” manufactured by Nippon Synthetic Chemical Co., Ltd. , "Purple light UV-7600B", "purple light UV-7605B", "purple light UV-7610B", "purple light UV-7620EA", "purple light UV-7630B" and "purple light UV-7640B", manufactured by Negami Kogyo Co., Ltd. “Art Resin UN-9000H”, “Art Resin UN-3320HA”, “Art Resin UN-3320HC”, “Art Resin UN-3320HS” and “Art Resin UN-901T”, manufactured by Shin-Nakamura Chemical Co., Ltd. "NK Oligo U-4HA", "NK Oligo U-6HA", "NK Oligo U-6LPA", "NK Oligo U-15H" ”,“ NK Oligo UA-32P ”,“ NK Oligo U-324A ”and“ NK Oligo U-6H ”,“ EBECRYL1204 ”,“ EBECRYL1205 ”,“ EBECRYL215 ”,“ EBECRYL230 ”manufactured by Daicel Cytec Co., Ltd. "EBECRYL244", "EBECRYL245", "EBECRYL264", "EBECRYL965", "EBECRYL845Y", "EBECRYL8405", "EBECRYL8405" ”,“ EBECRYL1290 ”,“ EBECRYL1290K ”,“ EBECRYL5129 ”,“ EBECRYL 10 ”,“ EBECRYL220 ”,“ EBECRYL284 ”,“ EBECRYL8210 ”,“ EBECRYL8402 ”and“ EBECRYL9260 ”,“ UX-2201 ”,“ UX-2301 ”,“ UX-3204 ”,“ UX-3204 ”manufactured by Nippon Kayaku Co., Ltd. “UX-3301”, “UX-4101”, “UX-0937”, “UX-5000”, “UX-5001”, “UX-5002”, “Beamset 575” manufactured by Arakawa Chemical Industries, Ltd., Tojo Examples thereof include “M-313” and “M-315” manufactured by Synthetic Co., Ltd. The skeleton of the acrylated urethane resin is not particularly limited, but those having a large number of acryl functional groups are remarkably cured and contracted, and are inferior in elastic modulus and warpage, so that the number of acryl functional groups in one molecule is preferably 2-4. In addition, if the value of the weight average molecular weight is small, adhesion of the artwork film to the substrate is likely to occur during exposure, and it becomes difficult to obtain the intended cured coating film. Since the folding endurance tends to be poor when the average molecular weight is large, the upper limit is preferably 3000. Therefore, for example, “EBECRYL 8405” manufactured by Daicel Cytec Co., Ltd., which is tetrafunctional and has a weight average molecular weight of 2700, and “EBECRYL215” manufactured by Daicel Cytec Co., Ltd. which is bifunctional and has a weight average molecular weight of 1,500 are preferable.

  When the above-mentioned acrylated urethane resin is contained in the solder resist composition, it is possible to form a solder resist film having excellent extensibility and folding resistance while suppressing the generation of elastic modulus and warping, so that it is possible to form a printed wiring board, particularly flexible wiring. It is advantageous for application to a board. The amount of the acrylated urethane resin used is 20 to 40 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin, and is 25 because it is excellent in the balance of low elasticity, high elongation, low warpage and folding resistance. -35 mass parts is preferable.

  (C) The photopolymerization initiator is not particularly limited as long as it is generally used. For example, an oxime initiator, benzoin, acetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1- ON, 1-hydroxycyclohexyl phenyl ketone, benzophenone and the like. The usage-amount of a photoinitiator is 5-20 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin, and 8-15 mass parts is preferable.

  (D) The diluent is, for example, a photopolymerizable monomer, and is used for obtaining a solder resist film having sufficient acid resistance, heat resistance, alkali resistance, etc., by sufficiently photocuring the carboxyl group-containing photosensitive resin. . Examples of the photopolymerizable monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and the like. Can be mentioned. The addition amount of a diluent is 2.0-40 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin, and 10-25 mass parts is preferable.

  (E) An epoxy compound is for raising the crosslinking density of a cured coating film, and obtaining sufficient cured coating film, for example, adds an epoxy resin. Examples of the epoxy resin include bisphenol A type epoxy resin, novolak type epoxy resin (phenol novolak type epoxy resin, o-cresol novolak type epoxy resin, p-tert-butylphenol novolak type, etc.), bisphenol F and bisphenol S with epichlorohydrin. Bisphenol F-type and bisphenol S-type epoxy resins obtained by reaction, alicyclic epoxy resins having cyclohexene oxide groups, tricyclodecane oxide groups, cyclopentene oxide groups, and the like, tris (2,3-epoxypropyl) isocyanurate , Triglycidyl isocyanurate having a triazine ring such as triglycidyl tris (2-hydroxyethyl) isocyanurate, dicyclopentadiene type epoxy resin, Adama It can be exemplified Tan type epoxy resin. These compounds may be used alone or in combination of two or more. The usage-amount of an epoxy compound is 10-50 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin from the point which obtains a sufficient coating film after hardening, and 20-30 mass parts is preferable.

  (F) The phosphorus element-containing organic filler is for imparting flame retardancy to the solder resist composition. For example, tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2- Chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate, tris (bromochloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromo) Halogen-containing phosphates such as phenyl) phosphate and tris (tribromoneopentyl) phosphate; trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate Any non-halogen aliphatic phosphate; triphenyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, xylenyl diphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyl diphenyl phosphate , Non-halogen aromatic phosphates such as diisopropylphenylphenyl phosphate, tris (trimethylphenyl) phosphate, tris (t-butylphenyl) phosphate, hydroxyphenyldiphenyl phosphate, octyldiphenyl phosphate; aluminum trisdiethylphosphinate, trismethylethylphosphine Aluminum acid, trisdiphenylphosphinic acid Zinc, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, bisdiphenylphosphine Examples thereof include metal salts of phosphinic acids such as titanyl acid and titanium tetrakisdiphenylphosphinate.

  Among these, non-halogen phosphates and metal salts of phosphinic acid are preferable from the viewpoint of preventing dioxin generation and reducing environmental impact, and in a small amount, not only flame resistance but also solder heat resistance, with metal A metal salt of phosphinic acid is particularly preferable from the standpoint of effective heat resistance. Further, among the metal salts of phosphinic acid, aluminum trisdiethylphosphinate is particularly preferable in terms of exhibiting excellent flame retardancy. Aluminum trisdiethylphosphinate is commercially available, for example, as “Exorit OP-935” manufactured by Clariant Japan Co., Ltd. and “Exorit OP-930” manufactured by the same company.

  In the case of phosphoric acid ester, the amount of the phosphorus element-containing organic filler used is sufficient flame retardancy with a lower limit of 5 parts by mass and an upper limit of 50 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin. The lower limit is preferably 10 parts by mass from the standpoint of securing the upper limit, and the upper limit is preferably 40 parts by mass from the viewpoint of reliably suppressing the decrease in the mechanical strength of the solder resist film. On the other hand, when the metal salt of phosphinic acid is used as the phosphorus element-containing organic filler, the amount used is 3 parts by mass for the lower limit and 20 parts by mass for 100 parts by mass of the carboxyl group-containing photosensitive resin. The lower limit is preferably 4 parts by mass from the viewpoint of securing sufficient flame retardancy, and the upper limit is preferably 15 parts by mass from the viewpoint of reliably suppressing the decrease in mechanical strength of the solder resist film.

  In the embodiment of the present invention, in order to further improve the stretchability and folding resistance while further suppressing the occurrence of elasticity and warpage, (G) a powder urethane resin may be further contained as necessary. The powdered urethane resin is not limited to a specific compound. For example, the compound having two or more isocyanate groups in one molecule and two or more hydroxyls in one molecule enumerated in the above (B) acrylated urethane resin. The thing obtained by making the polyol compound which has group react is mentioned. The lower limit of the particle size of the powder urethane resin is 0.1 μm from the viewpoint of obtaining sufficient flexibility by suppressing the elastic modulus, avoiding the difficulty of kneading when making ink, and further increasing thixotropy And 1.0 micrometer is preferable from the point which prevents that rheology control becomes difficult. On the other hand, the upper limit of the particle diameter of the powder urethane resin is 30 μm from the viewpoint of obtaining fine image formation, and preferably 10 μm from the viewpoint of facilitating the formation of a fine pattern. The shape of the particles is not particularly limited, and may be spherical or indefinite. The amount of the powdered urethane resin is 10 to 30 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of further improving elongation and folding resistance while further suppressing the generation of warpage in addition to elasticity. It is preferably 12 to 18 parts by mass from the viewpoint of excellent balance of the above characteristics. Examples of commercially available powdered urethane resins include “RHC-730” manufactured by Dainichi Seika Co., Ltd., “Art Pearl C-300”, “C-400” manufactured by Negami Kogyo Co., Ltd. “C-800”, “P-800T”, “U-600T”, “CF-600T”, “JB-400T”, “JB-800T”, “CE-400T”, “CE” -800T "," Same MM-120TW "," Same C-400R ", etc.

  In addition to the above components, the flame retardant solder resist according to the embodiment of the present invention may include various additive components, for example, colorants, antifoaming agents, various additives, solvents, extender pigments, and the like. Can be contained.

  As the colorant, known color pigments can be used, and examples thereof include phthalocyanine-based organic pigments such as phthalocyanine green and phthalocyanine blue, anthraquinone-based and azo-based organic pigments, and inorganic pigments such as titanium oxide and carbon black. Moreover, a well-known thing can be used for an antifoamer, For example, a silicone type, a hydrocarbon type, an acrylic type etc. can be mentioned.

  Examples of additives include dispersants such as coupling agents such as silane, titanate, and alumina, boron trifluoride-amine complex, dicyandiamide (DICY) and its derivatives, organic acid hydrazide, and diaminomaleonitrile (DAMN). And its derivatives, melamine and its derivatives, guanamine and its derivatives, amine imide (AI) and latent curing agents such as polyamine, metal salts of acetylacetone such as acetylacetonate Zn and acetylacetonate Cr, enamine, tin octylate, Examples include quaternary sulfonium salts, triphenylphosphine, imidazole, imidazolium salts, and thermosetting accelerators such as triethanolamine borate.

  The solvent is for adjusting the viscosity and drying property of the flame retardant solder resist composition. For example, ketones such as methyl ethyl ketone and cyclohexane, aromatic hydrocarbons such as toluene and xylene, methanol, isopropanol, cyclohexane Alcohols such as hexanol, cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane, petroleum solvents such as petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, Examples thereof include acetates such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and butyl carbitol acetate. The extender pigment is for increasing the physical strength of the coated solder resist film, and examples thereof include silica, barium sulfate, alumina, aluminum hydroxide, talc, and mica.

  Although the manufacturing method of the flame-retardant solder resist composition according to the above-described embodiment of the present invention is not limited to a specific method, for example, after blending the above components at a predetermined ratio, they are mixed by three rolls at room temperature. It can be produced by dispersing.

  Next, the coating method of the flame retardant solder resist composition according to the above-described embodiment of the present invention will be described. The flame-retardant solder resist composition according to the embodiment of the present invention obtained as described above is used, for example, on a flexible wiring board having a circuit pattern formed by etching a copper foil, using a screen printing method or the like. In order to volatilize the solvent in the flame retardant solder resist composition, preliminary drying is performed by heating at a temperature of about 60 to 80 ° C. for about 15 to 60 minutes. Then, the negative film which has the pattern which made translucent except the land of the said circuit pattern is closely_contact | adhered on the apply | coated flame-retardant soldering resist composition, and an ultraviolet-ray is irradiated from it. Then, the coating film is developed by removing the non-exposed areas corresponding to the lands with a dilute alkaline aqueous solution. As a developing method, a spray method, a shower method, or the like is used. As a dilute alkali aqueous solution used, a 0.5 to 5% sodium carbonate aqueous solution is generally used, but other alkalis can also be used. Next, the target solder resist film can be formed on the flexible wiring board by performing post-cure for 20 to 80 minutes with a hot air circulation dryer at 130 to 170 ° C.

  An electronic circuit unit is formed by soldering an electronic component to the flexible wiring board covered with the solder resist film thus obtained by a jet soldering method, a reflow soldering method, or the like.

  Further, a white pigment (for example, titanium oxide such as rutile type titanium oxide) as a colorant is added to 100 parts by weight of the carboxyl group-containing photosensitive resin in the flame retardant solder resist composition according to the above-described embodiment of the present invention. By adding 20 to 200 parts by mass, a white curable resin composition having flame retardancy can be obtained, and a reflective sheet can be obtained by applying this white curable resin composition on a sheet-like base film. it can. For example, the said reflection sheet is arrange | positioned as a back sheet | seat on the back surface side of a solar cell module, ie, the surface on the opposite side to the surface which receives solar radiation. Then, since the sunlight that has passed through the solar cell module without being received by the power generation element of the solar cell module is reflected by the reflection sheet and returned from the back side of the solar cell module to the inside of the solar cell module, the solar cell The power generation efficiency of the module is improved. In addition, the installation method of the reflective sheet to a solar cell module back surface includes the method of sticking directly on a solar cell module back surface using an adhesive agent or an adhesive tape, for example.

  The material of the base film to which the white curable resin composition is applied is not particularly limited. For example, polyimide, polyethylene terephthalate (PET), polyvinyl fluoride (PVF), fluorinated ethylene / propylene copolymer (FEP), Examples include polytetrafluoroethylene (PTFE), aramid, polyamide-imide, epoxy, polyetherimide, polysulfone, polyethylene naphthalate (PEN), and liquid crystal polymer (LCP).

  The method for coating the white curable resin composition on the sheet-like base film is not particularly limited, and includes the following coating methods in addition to the same coating method as described above. Specifically, the surface of a polyethylene terephthalate film having a thickness of 40 μm is treated with 3% sulfuric acid to wash the surface, and then a white flame-retardant solder resist composition is formed on the washed surface using a known printing method such as screen printing. The product is coated so as to have a predetermined thickness, for example, a cured film thickness of 20 to 23 μm. The white curable resin composition is coated on the entire or substantially entire surface of the base film facing the back surface of the solar cell module. After coating, preliminary drying is performed by heating at a temperature of about 60 to 80 ° C. for about 15 to 60 minutes. Subsequently, the target white film | membrane can be formed on a sheet-like base film by performing a postcure for 10 to 80 minutes at the temperature of about 130-170 degreeC.

  Next, examples of the present invention will be described. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Examples 1-8, Comparative Examples 1-3
Each component shown in the following Table 1 is blended at the blending ratio shown in the following Table 1, and premixed with a stirrer, and then mixed and dispersed at room temperature using three rolls. Examples 1 to 8 and Comparative Example The solder resist composition used in 1-3 was prepared. And the prepared soldering resist composition was applied as follows and the test piece was created. The numbers in Table 1 below indicate parts by mass.

The details of each component in Table 1 are as follows.
(A) Carboxyl group-containing photosensitive resin
-ZFR-1124: Nippon Kayaku Co., Ltd. product, carboxyl group-containing photosensitive resin using a polyfunctional epoxy resin having a bisphenol F structure.
FLX-2089: a photosensitive carboxyl group-containing resin using a urethane-modified epoxy resin manufactured by Nippon Kayaku Co., Ltd.
Cyclomer P (ACA) Z-250: a photosensitive carboxyl group-containing resin using an acrylic copolymer structure resin manufactured by Daicel Chemical Industries, Ltd.
(B) Acrylic urethane resin
EBECRYL 8405: A tetrafunctional, acrylated urethane resin having a weight average molecular weight of 2700, manufactured by Daicel Cytec Co., Ltd.
EBECRYL 215: a bifunctional, acrylated urethane resin with a weight average molecular weight of 1500 , manufactured by Daicel-Cytec.
UX-5002: Nippon Kayaku Co., Ltd., pentafunctional, acrylated urethane resin with a weight average molecular weight of 2900.
UX-0937: Nippon Kayaku Co., Ltd. bifunctional, acrylated urethane resin with a weight average molecular weight of 4000.
EBECRYL 8804: a bifunctional, acrylated urethane resin having a weight average molecular weight of 1300, manufactured by Daicel-Cytec.
(C) Photopolymerization initiator
・ Irgacure 907: Ciba Specialty Chemicals
(E) Epoxy compound
EPICRON 860: Dainippon Ink & Chemicals, bisphenol A type epoxy resin.
(G) Powder urethane resin
RHC-730: manufactured by Dainichi Seika Co., Ltd., particle size 5 to 7 μm.

  In addition, KS-66 is a silicone-based antifoaming agent manufactured by Shin-Etsu Chemical Co., Ltd., the additive R-974 is a thixotropy imparting agent manufactured by Nippon Aerosil Co., Ltd., and DICY-7 is Japan Epoxy Resin Co., Ltd. It is a hardening accelerator. In addition, the colorant has a color tone similar to that of polyimide, which is the base material of the flexible substrate, and CIPigment Blue 15: 3 (Lionol Blue FG-7351 manufactured by Toyo Ink Co., Ltd.) and CI. Pigment Orange71 (manufactured by Ciba Specialty Chemicals) Chromophthal OPP Orange TR) was used.

Test piece preparation process 1
This is a test piece preparation process for evaluating the elastic modulus and elongation rate. After the solder resist composition is uniformly applied to a PET film so as to have a thickness of 50 μm ± 10 μm by using a bar coater, in a BOX furnace And preliminary drying at 70 ° C. for 20 minutes. After the preliminary drying, the applied solder resist composition was irradiated with 400 mJ / cm ² of ultraviolet rays using an exposure apparatus (“HMW-680GW” manufactured by Oak Co., Ltd.). After the irradiation, development was performed with a 1 mass% aqueous sodium carbonate solution at 30 ° C. under a spray pressure of 0.1 MPa for 60 seconds to draw a pattern. After development, a cured coating film was obtained by post-curing at 150 ° C. for 60 minutes in a BOX furnace to obtain a cured coating film, and a test piece for evaluating the elastic modulus and elongation rate was prepared.

(1) Elastic modulus (GPa)
For the test piece prepared in the test piece preparation step 1, an autograph (manufactured by SHIMAZU) is used under the condition of a pulling speed of 5 mm / min for the one obtained by peeling the cured coating film from the PET film and cutting it to a predetermined size. The elastic modulus was measured. Regarding the measurement results, the elastic modulus of less than 3.0 GPa was evaluated as “◎”, the elastic modulus of 3.0 to 5.0 GPa was evaluated as “◯”, and the elastic modulus of over 5.0 GPa was evaluated as “x”.
(2) Growth rate (%)
Using the same sample as that prepared at the time of measuring the elastic modulus, the elongation was measured using an autograph (manufactured by SHIMAZU) under the condition of a pulling speed of 5 mm / min. About the measurement result, the elongation rate of more than 8.0% was evaluated as “◎”, the elongation rate of 1.0 to 8.0% was evaluated as “◯”, and the elongation rate of less than 1.0% was evaluated as “x”.

Test piece preparation process 2
This is a test piece preparation process for evaluating the amount of warpage, combustibility, folding resistance, and solder heat resistance, and a circuit pattern was provided on a polyimide film having a thickness of 25 μm (“Kapton 100H” manufactured by Toray DuPont Co., Ltd.). After surface treatment with a 3% sulfuric acid aqueous solution for the flexible wiring board, a solder resist composition is applied by a screen printing method so that the DRY film thickness is 20 to 23 μm, and a preliminary test is performed at 70 ° C. for 20 minutes in a BOX furnace. Drying was performed. After the preliminary drying, the applied solder resist composition was irradiated with 400 mJ / cm ² of ultraviolet rays using an exposure apparatus (“HMW-680GW” manufactured by Oak Co., Ltd.). After the irradiation, development was performed with a 1 mass% aqueous sodium carbonate solution at 30 ° C. under a spray pressure of 0.1 MPa for 60 seconds to draw a pattern. After development, a cured coating film is obtained by post-curing at 150 ° C. for 60 minutes in a BOX furnace to obtain a cured coating film, and a test for evaluating the warpage amount, combustibility, folding resistance, and solder heat resistance. Created a piece.

(3) Warpage After cutting the test piece created in the test piece preparation step 2 into 3 cm x 3 cm, place the test piece gently on a horizontal table so that the top is concave, and do not apply any external force. The vertical distance between the four corners and the table was measured to a unit of 1 mm with a straight scale, and the maximum value was taken as the amount of warpage. Regarding the measurement results, the warpage amount of less than 5 mm was evaluated as “◎”, the warpage amount of 5 to 8 mm was evaluated as “◯”, and the warpage amount of more than 8 mm was evaluated as “x”.
(4) Flammability The test piece created in the test piece creation step 2 was subjected to a vertical combustion test based on the UL94 standard. Evaluation was expressed as VTM-0 to combustion based on the UL94 standard.
(5) Folding resistance About the test piece created in the test piece creation step 2, 180 ° folding is repeated several times by goby folding, and the occurrence of cracks in the coverlay at that time is visually observed with an optical microscope of × 200. Observe and measure the number of times cracks did not occur. About the measurement result, 4 times or more was evaluated as "(double-circle)", 2-3 times was evaluated as "(circle)", and 0-1 time was evaluated as "x".
(6) Solder heat resistance The cured coating film of the test piece prepared in the test piece preparation step 2 was immersed in a solder bath at 260 ° C. for 30 seconds in accordance with the test method of JIS C-6481, and then a peeling test using a cellophane tape was performed. The coating film state after repeating this 1 to 3 times was visually observed. As for the observation results, “◎” indicates that no change is observed in the coating even after 3 cycles, “◯” indicates that the coating is slightly changed after 3 cycles, and “○” indicates that the change after 2 cycles is repeated. A film where a change was observed was evaluated as “Δ”, and a film where peeling was observed after one cycle was evaluated as “x”.

  Table 2 shows the measurement results of the elastic modulus, elongation, warpage and folding resistance, and Table 3 shows the evaluation results and observation results of the elastic modulus, elongation, warpage, combustibility, folding resistance and solder heat resistance. .

  As shown in the said Table 2 and Table 3, Examples 1-8 which mix | blended the organic filler containing a phosphorus atom did not burn, but flame retardance was recognized. On the other hand, the comparative examples 2 and 3 which did not mix | blend the organic filler containing a phosphorus atom burned. Moreover, although Examples 1-8 which mix | blended the acrylation urethane resin were suppressed warpage and low elasticity, the outstanding elongation property, and bending resistance were recognized, on the other hand, the acrylated urethane resin was mix | blended. In Comparative Examples 1 and 3, the occurrence of warpage was not suppressed, the elasticity was increased, and the stretchability and folding resistance were remarkably inferior. Further, in Example 8 in which the powdered urethane resin was blended, warpage was suppressed particularly compared to other examples in which the powdered urethane resin was not blended, and more excellent elongation and folding resistance were recognized. .

  Example 1 in which ZFR-1124 using a polyfunctional epoxy resin having a bisphenol F structure was blended with respect to a carboxyl group-containing photosensitive resin was blended with a cyclomer P (ACA) Z-250 using a resin having an acrylic copolymer structure. Compared with Example 7, the occurrence of warpage was further suppressed, and the low elasticity, stretchability, and folding resistance were more excellent.

Examples 9-16, Comparative Examples 4-6
Each component shown in the following Table 4 was blended at the blending ratio shown in the following Table 4, premixed with a stirrer, then mixed and dispersed at room temperature using three rolls, Examples 9 to 16 and Comparative Examples The white curable resin composition used in 4-6 was prepared. And the prepared white curable resin composition was applied as follows, and the test piece was created. The numbers in Table 4 below indicate parts by mass.

The details of each component in Table 4 are as follows.
CR-80: Rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd.
The details of the other components are the same as those described in Table 1 above.

Test piece preparation process 3
This is a test piece preparation process for evaluating the warpage, folding resistance, flammability, and pencil hardness of a white curable resin composition containing titanium oxide, and is a polyethylene terephthalate film (Toray Industries, Inc.) with a thickness of 40 μm. , “Lumilar”) was treated with a 3% aqueous sulfuric acid solution to clean the surface, and then the white curable resin composition was applied to one entire surface of the polyethylene terephthalate film so that the DRY film thickness was 20 to 23 μm. It apply | coated by the screen-printing method and performed the preliminary drying for 20 minutes at 70 degreeC in the BOX furnace. After preliminary drying, a cured coating film was obtained by post curing at 150 ° C. for 60 minutes to obtain a cured coating film, and a test piece was prepared. In addition, in order to remove the influence of the deterioration of the polyethylene terephthalate film itself accompanying the environmental standing test, the reflectance was obtained by obtaining a cured coating film on the glass plate in the same process as described above to prepare a test piece.

(7) Reflectance Using a spectrophotometer U-3410 (manufactured by Hitachi, Ltd .: φ60 mm integrating sphere), the reflectance at 450 nm of the test piece coated with the cured coating film was measured. “Initial” means post-cure, “after irradiation” means UV irradiation at 50 J / cm ^{2 for} 2 minutes, “after heating” means heat treatment at 170 ° C. for 100 hours, “after heating and humidification” "Means after 1000 hours at 85 ° C and 85% RH.
(8) Pencil hardness Press the B to 9H pencil sharpened so that the tip of the core is flat against the cured coating film at an angle of about 45 °, and the pencil hardness will not cause the coating film to peel off. Recorded.
In addition, the evaluation method of curvature property, combustibility, and bending resistance is the same as the said test piece preparation process 2. FIG.

  Table 5 shows measurement results of warpage, folding resistance, reflectance, and pencil hardness, and Table 6 shows evaluation results of warpage, combustibility, and folding resistance.

  As shown in Table 6 above, Examples 9 to 16 in which an organic filler containing phosphorus atoms was blended did not burn and flame retardancy was recognized. On the other hand, the comparative examples 5 and 6 which did not mix | blend the organic filler containing a phosphorus atom burned. Moreover, as shown in Table 5 and Table 6, Examples 9-16 which mix | blended acrylated urethane resin have curvature property, suppressing the fall of the reflectance after an ultraviolet irradiation, a heating, and after humidification heating. It was suppressed and excellent folding resistance was recognized. Moreover, in Examples 9-16, pencil hardness was 4H-5H and was excellent in coating-film hardness. Accordingly, when the sheets coated with the white curable resin compositions of Examples 9 to 16 are used as, for example, a back sheet of a solar cell, a decrease in reflectance due to solar radiation, solar heat and aging can be suppressed, and low Since it is excellent in adhesion to the solar cell module due to warpage, it is possible to maintain improvement in power generation efficiency over a long period even in a harsh natural environment. Moreover, since the white curable resin composition of Examples 9-16 is excellent in folding resistance and coating-film hardness, it can prevent peeling from the sheet | seat at the time of processing of a back sheet, transportation, installation, etc. On the other hand, in Comparative Examples 4 and 6 in which no acrylated urethane resin was blended, the occurrence of warpage was not suppressed and the folding resistance was remarkably inferior. Further, in Example 16 in which the powdered urethane resin was blended, warpage was particularly suppressed and more excellent folding resistance was recognized as compared with other examples in which the powdered urethane resin was not blended.

  The present invention provides a solder resist composition capable of forming a solder resist excellent in flame retardancy, low elasticity, high elongation and folding resistance in addition to adhesion to a substrate, low warpage, and solder heat resistance. Therefore, the utility value is particularly high in the field of flexible wiring boards that require excellent flame retardancy and a soft structure, and the field of reflective sheets provided on the back surface of solar cell modules.

Claims (6)

(A) a carboxyl group-containing photosensitive resin, (B) a acrylic urethane resin, (C) a photopolymerization initiator, (D) a diluent, (E) an epoxy compound and (F) a phosphorus element-containing organic filler including flame a retardant solder resist composition,
The flame retardant solder resist composition, wherein the (B) acrylated urethane resin has 2 to 4 acryloyl groups in one molecule and has a weight average molecular weight of 1500 to 3000 .   The flame retardant solder resist composition according to claim 1, wherein the (F) phosphorus element-containing organic filler is a metal salt of phosphinic acid.   The flame retardant solder resist composition according to claim 1, further comprising (G) a powder urethane resin. The flame retardant according to claim 3 , wherein the powder urethane resin (G) is contained at a ratio of 10 to 30 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. Solder resist composition. The flexible wiring board which has a membrane | film | coat obtained by photocuring the flame-retardant soldering resist composition of any one of Claims 1-4 . It has the film | membrane obtained by apply | coating the flame retardant solder resist composition of any one of Claims 1-4 further with the white flame retardant solder resist composition containing the titanium oxide. Reflective sheet.