JP2009194222A - White alkali-developable photocurable and thermosetting solder resist composition, and metal-base circuit substrate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-reflectance alkali-developable photocurable and thermosetting solder resist composition, and a metal-base circuit substrate using the same having a high reflection function. <P>SOLUTION: The white alkali-developable photocurable and thermosetting solder resist composition comprises (A) a carboxyl-containing (meth)acrylate having no aromatic ring, (B) a (meth)acryl compound, (C) a photopolymerization initiator, (D) an epoxy compound, (E) a curing agent for thermosetting, (F) a curing catalyst for thermosetting, (G) inorganic powder, and (H) an organic solvent. The metal-base circuit substrate comprises an insulating layer formed on metal foil, and a circuit formed on the insulating layer wherein a white film is formed on the insulating layer and the circuit using the solder resist composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a white alkali-developable photocurable / thermosetting solder resist composition and a metal base circuit board using the same.

  Conventionally, liquid crystal display devices have been used in various fields, and in particular, have been used in many fields in the electronic industry such as personal computers and televisions. Among these liquid crystal display devices, particularly those that employ a direct type backlight system, a backlight is disposed on the back of the liquid crystal panel, and the backlight uses the light emitted from the light source as a light guide plate. Incident light is transmitted, and the propagated light is emitted from the front surface side of the light guide plate through a prism sheet or the like, so that the entire back surface of the liquid crystal panel is irradiated. As a light source of the backlight, a small fluorescent tube called a CFL (cold cathode tube) or a light emitting diode (LED) is often used. However, in recent years, due to environmental considerations, backlights using LEDs as light sources are spreading instead of CFLs using mercury.

  In addition, it is desired to further increase the area of a liquid crystal display device for television, and for this purpose, a large amount of light is required. Therefore, it is necessary to supply as much light as possible to the liquid crystal part. For this reason, in order to maximize the amount of light supplied from the backlight, it is necessary to effectively use not only the emitted light from the LED but also the reflected light. In order to effectively use the reflected light, it is common to use a light reflecting sheet.

  Conventionally, as a method of using a light reflection sheet for a direct type backlight using LEDs as a light source, an LED package is mounted on a printed circuit board, and a light reflection sheet is pasted on the printed circuit board. As described above, the printed circuit board and the light reflecting sheet are different from each other (Patent Document 1).

  Moreover, the conventional printed wiring board which has a soldering resist film has not reached the substitute of the light reflection sheet for raising the utilization efficiency of the light of LED (patent documents 2-9).

JP 2006-310014 A Japanese Patent Publication No. 1-54390 Japanese Patent Publication No. 7-17737 JP-A-9-183920 JP 2005-108896 A JP 2005-31233 A JP 2006-96962 A JP 2007-101830 A JP 2007-322546 A

  Conventionally, a printed circuit board for mounting an LED package for a direct type backlight has no light reflecting function. Therefore, when used as a printed circuit board for a backlight, it is necessary to attach a light reflecting sheet after mounting the LED package. there were. For this reason, there has been a problem that the number of man-hours and necessary members at the time of manufacture are complicated and handling is complicated in the manufacturing process, which is inconvenient.

  The present invention has been made in view of the above circumstances, and provides a white alkali-developable photocurable / thermosetting solder resist composition having a high light reflectance, and a completely new metal base circuit board using the same. Objective.

  According to the present invention, (A) a carboxyl group-containing (meth) acrylate having no aromatic ring, (B) a (meth) acrylic compound, (C) a photopolymerization initiator, (D) an epoxy compound, (E) a thermosetting curing agent, (F) a curing catalyst for thermosetting, (G) an inorganic powder, and (H) an organic solvent. A thermosetting solder resist composition is provided.

  According to such a composition, the soldering resist composition which can form a coating film with high light reflectance is obtained. As a result, it is possible to improve the quality of electronic parts and improve reliability.

  Furthermore, according to the present invention, in a metal base circuit board in which an insulating layer is formed on a metal foil and a circuit is formed on the insulating layer, the alkali development type photo-curing property is formed on the insulating layer and the circuit. There is provided a metal base circuit board obtained by forming a solder resist film using a thermosetting solder resist composition.

  Such a circuit board can effectively use reflected light only with a metal-based circuit board without attaching a light reflecting sheet, thereby improving productivity by simplifying the manufacturing process and reducing necessary components. Etc. can be achieved.

  According to the present invention, by setting the composition of the solder resist composition as described above, it is possible to form a solder resist coating film having a high light reflectance, and without attaching a light reflecting sheet after LED mounting, The reflected light can be effectively used only with the metal base circuit board.

  Hereinafter, embodiments of the present invention will be described in detail.

<Explanation of terms>
In the present specification, white means that the light is continuously reflected at a high reflectance in the visible light region of 400 to 800 nm, for example, 80% or more in the ratio of the light intensity of the incident light to the reflected light.
In the present specification, the alkali-developable photocurable / thermosetting solder resist composition is:
It means a solder resist composition capable of alkali development and capable of photocuring and / or heat curing.
In this specification, the solder resist composition means a heat-resistant coating material for protecting a portion that does not require soldering when soldering a circuit board or the like.
In this specification, (meth) acrylate is a general term for methacrylate and acrylate.
In the present specification, the description “to” includes numerical values of the lower limit and the upper limit of the defined range, and means a range of “more than the lower limit value and less than the upper limit value”.
In the present specification, the molecular weight means a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (hereinafter referred to as GPC) or the like.

<Embodiment>
<Solder resist composition>
A white alkali-developable photocurable / thermosetting solder resist composition according to an embodiment of the present invention includes (A) a carboxyl group-containing (meth) acrylate having no aromatic ring, and (B) (meth). An acrylic compound, (C) a photopolymerization initiator, (D) an epoxy compound, (E) a thermosetting curing agent, (F) a thermosetting curing catalyst, (G) an inorganic powder, and (H) An organic solvent.

  According to the said composition, the soldering resist composition which can form a soldering resist coating film with a high light reflectance can be provided.

<(A) Carboxyl group-containing (meth) acrylate having no aromatic ring>
The (A) carboxyl group-containing (meth) acrylate having no aromatic ring is not particularly limited as long as the resin does not have an aromatic ring and has a carboxyl group.
Examples of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring include acid group-containing acrylate manufactured by Daicel-Cytec Co., Ltd., product names CYCLOMER (ACA200M, ACA230AA, ACAZ250, ACAZ251, ACAZ300, and ACAZ320). ), Product names AGOR4120, ORGA4060, etc. of Osaka Organic Chemical Industry Co., Ltd. can be mentioned. These carboxyl group-containing (meth) acrylates having no aromatic ring can be used alone or in combination of two or more.

  The (A) carboxyl group-containing (meth) acrylate having no aromatic ring preferably has a resin acid value in the range of 30 mgKOH / g to 150 mgKOH / g. When the resin acid value is 30 mgKOH / g or more, it is easy to remove the unexposed portion with a weak alkaline aqueous solution. Moreover, if the resin acid value is 150 mgKOH / g or less, the water resistance, electrical characteristics, etc. of the cured coating are improved.

  Moreover, it is preferable that the weight average molecular weight of the said (A) carboxyl group-containing (meth) acrylate which does not have an aromatic ring exists in the range of 5,000-100,000. If the weight average molecular weight is 5,000 or more, the dryness to touch is good. Moreover, if a weight average molecular weight is 100,000 or less, developability and storage stability will be improved.

<(B) (Meth) acrylic compound>
The (B) (meth) acrylic compound is not particularly limited, and means an acrylic compound and / or a methacrylic compound.
Examples of the (B) (meth) acryl compound include mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl Hydroxyalkyl acrylates such as acrylate; acrylamides such as N, N-dimethylacrylamide and N-methylolacrylamide; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate; hexanediol, trimethylolpropane, pentaerythritol, di Polyhydric alcohols such as pentaerythritol and tris-hydroxyethyl isocyanurate, or their ethylene oxide or propylene ox Polyhydric acrylates of idoid adducts; Phenoxy acrylate, bisphenol A diacrylate and acrylates such as ethylene oxide or propylene oxide adducts of these phenols; Glycidyl such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether Acrylates of ethers; melamine acrylates; and / or methacrylates corresponding to the above acrylates, tricyclodecyl methacrylate, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimethacrylate, 1,6-hexanediol glycidyl ether acrylate , Acrylic acid modification of hexahydrophthalic acid diglycidyl ester, tetrahydrofurfuryl acrylate, It can be exemplified acryloyl group silsesquioxane derivatives. These (meth) acrylic compounds can be used alone or in combination of two or more. Among these, terminal acryloyl group silsesquioxane derivatives and the like are preferable because of excellent transparency.

  The blending amount of the (B) (meth) acrylic compound is preferably 300 to 850 parts by weight, particularly preferably 400 to 800, with respect to 100 parts by weight of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring. Part by mass. When the blending amount of the (B) (meth) acrylic compound is 300 parts by mass or more or 400 parts by mass or more, the heat resistance is improved. On the other hand, when the blending amount of the (B) (meth) acrylic compound is 850 parts by mass or less or 800 parts by mass or less, the solubility of the white film during alkali development is improved, which is preferable.

<(C) Photopolymerization initiator>
The (C) photopolymerization initiator is not particularly limited, and includes a compound capable of initiating polymerization of monomers and oligomers by light irradiation.
Examples of the (C) photopolymerization initiator include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1, Acetophenones such as 1-dichloroacetophenone; benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopro Pan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1 Aminoalkylphenones such as butanone; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2- Thioxanthones such as chlorothioxanthone and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; benzophenones such as benzophenone; or xanthones; (2,6-dimethoxybenzoyl) -2,4,4 -Pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Phosphine oxide such as chill-2,4,6-trimethyl benzoyl phenyl phosphinothricin Nate; various peroxides, and the like titanocene initiators. These are also light such as tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine and the like. You may use together with a sensitizer etc. The said (C) photoinitiator can be used individually or in combination of 2 or more types.

  The blending amount of the (C) photopolymerization initiator is 100 parts by mass of the total of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring and the (B) (meth) acrylic compound. Preferably they are 2 mass parts-6 mass parts, More preferably, they are 3 mass parts-5 mass parts. When the blending amount of the (C) photopolymerization initiator is 2 parts by mass or more or 3 parts by mass or more, the photocurability is high and pattern formation after exposure / development is facilitated. Moreover, if the compounding quantity of the said (C) photoinitiator is 6 mass parts or less or 5 mass parts or less, since it is excellent in thick film sclerosis | hardenability, it is preferable.

<(D) Epoxy compound>
The (D) epoxy compound is not particularly limited, and includes a compound containing an epoxy ring.
Examples of the epoxy compound (D) include various known and commonly used epoxy resins such as bisphenol S-type epoxy resin, diglycidyl phthalate resin, triglycidyl isocyanurate (for example, TEPIC-H (S-triazine ring manufactured by Nissan Chemical Co., Ltd.). Β-form having a structure in which three epoxy groups are bonded in the same direction to the skeleton plane, and TEPIC (beta-form, one epoxy group for the S-triazine ring skeleton plane is the other two epoxy groups. Etc.), etc., etc.), bixylenol type epoxy resins, biphenol type epoxy resins, bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, Bisphenol F type resin, brominated bisphenol A type epoxy resin, phenol novolac type or Resole novolac epoxy resin, cycloaliphatic epoxy resin, bisphenol A novolac epoxy resin, chelate epoxy resin, glyoxal epoxy resin, amino group-containing epoxy resin, rubber-modified epoxy resin, dicyclopentadiene phenolic epoxy resin, silicone Examples thereof include modified epoxy resins and ε-caprolactone-modified epoxy resins. These epoxy compounds can be used alone or in combination of two or more.

  Among the above, it is more preferable to use an epoxy resin having no aromatic ring. Among them, since the alicyclic epoxy resin has transparency in a low wavelength region to a high wavelength region, the reflectance of the inorganic powder can be efficiently used, and the high reflectance can be achieved. .

  Examples of the alicyclic epoxy resin include product names Celoxide 2021P and Servenus B0134 manufactured by Daicel Chemical Industries, Ltd. These alicyclic epoxy resins can be used alone or in combination of two or more.

  The blending amount of the (D) epoxy compound is preferably 90 to 400 parts by weight, particularly preferably 150 to 300 parts by weight with respect to 100 parts by weight of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring. It is. If the blending amount of the (D) epoxy compound is 400 parts by mass or less or 300 parts by mass or less, it is difficult to cause a decrease in solubility of the unexposed part in the developing solution or development residue, and the practical use. Is suitable. On the other hand, when the blending amount of the (D) epoxy compound is 90 parts by mass or more or 150 parts by mass or more, the electrical characteristics, solder heat resistance, chemical resistance, etc. of the cured coating film are improved.

<(E) Curing agent for thermosetting>
The (E) thermosetting curing agent is not particularly limited, and includes a compound capable of initiating a curing reaction under normal temperature or high temperature conditions.
As the (E) thermosetting curing agent, known amines or acid anhydrides can be used.

  Examples of amines include melamine, dicyandiamide, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylaminopropylamine, isophoronediamine, 1,3- Bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norborneneamine, 1,2-diaminocyclohexane, laromine, diaminodiphenylmethane, metaphenyldiamine, diaminodisulfone, polyoxypropylenediamine, polyoxypropylenetriamine, polycyclohexylpolyamine A mixture, N-aminoethyl piperazine, etc. can be mentioned. These amines can be used alone or as a mixture of two or more.

  Among the above, it is preferable to use dicyandiamide because it does not have an aromatic ring, storage stability, and will not be dissolved during the heating step during the formation of the coating film as described later.

  The amount of dicyandiamide is 3 to 6 parts by mass, preferably 4 to 5 parts by mass, based on 100 parts by mass of the epoxy compound. When the blending amount of dicyandiamide is 3 parts by mass or more or 4 parts by mass or more, the curability of the coating film is improved, and electrical characteristics, solder heat resistance, and chemical resistance are sufficiently obtained. On the other hand, when the amount of dicyandiamide is 6 parts by mass or less or 5 parts by mass or less, discoloration of the coating film, cracking of the coating film, and the like are less likely to occur.

  Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis (anhydro trimellitate), glycerol tris (anhydro trimellitate), maleic anhydride , Tetrahydromaleic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride Acid, succinic anhydride, methylcyclohexene dicarboxylic acid anhydride, alkylstyrene-maleic anhydride copolymer polyazeline acid anhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid anhydride, 3 or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride 3 or 4-methyl-hexahydromethyl phthalic anhydride-3,6 endomethylene-1,2,3,6-tetrahydrophthalic anhydride, etc. Can be mentioned. These acid anhydrides can be used alone or as a mixture of two or more.

  The compounding amount of the acid anhydride is obtained by dividing the acid anhydride equivalent by the epoxy equivalent and further multiplying by 100 to 100 parts by mass of the epoxy resin. However, when a curing accelerator is used in combination, the acid anhydride equivalent is divided by the epoxy equivalent, and further multiplied by 100, and further multiplied by 0.9 to 0.95 is 100 parts by mass of the epoxy resin. It is the blending amount.

<(F) Curing catalyst for thermosetting>
The (F) thermosetting curing catalyst is not particularly limited, and includes a compound capable of promoting the thermosetting reaction.
As said (F) curing catalyst for thermosetting, an imidazole type is preferable from a viewpoint of hardening acceleration, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl -4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,3-dihydro-1H-pyrrolo [1,2 -A] benzimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino -6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 1-silane Anomethyl-2-methylimidazole and the like are preferred. The amount added may be arbitrarily changed in order to obtain a desired curing rate.

<(G) Inorganic powder>
The (G) inorganic powder is not particularly limited, and a white inorganic compound can be used.
The inorganic powder (G) is, for example, selected from rutile type titanium oxide, barium sulfate, zirconium oxide, talc, mica, silicon dioxide, zinc oxide, magnesium oxide and aluminum oxide. It is essential. As a preferred inorganic powder blend, rutile type titanium oxide, zirconium oxide, talc combination, rutile type titanium oxide, zirconium oxide, mica combination, rutile type titanium oxide, zirconium oxide, talc, mica combination and rutile type titanium oxide, There is a combination of zirconium oxide and barium sulfate.

  Moreover, it is preferable that the said inorganic powder (G) contains a rutile type titanium oxide, barium sulfate, and a zirconium oxide in single substance or in combination of 2 or more types. According to such a combination, since the film forming property and the concealing property are excellent, a coating film having excellent light reflectance is formed.

  Moreover, it is preferable that the said inorganic powder (G) contains a rutile type titanium oxide, barium sulfate, and a zirconium oxide in combination of 2 or more types. According to such a combination, since the film forming property and the concealing property are excellent, a coating film having excellent light reflectance is formed.

  More preferably, the (G) inorganic powder is a combination of rutile titanium oxide, zirconium oxide, and barium sulfate. According to such a combination, since the film forming property and the concealing property are excellent, a coating film having a further excellent light reflectance is formed.

  The blending amount of the (G) inorganic powder is 100 masses of the total of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring, the (B) (meth) acryl compound, and the (D) epoxy compound. Parts, preferably 350 to 700 parts by mass, more preferably 360 to 680 parts by mass. When the blending amount of the inorganic powder (G) is 350 parts by mass or more, the decrease in reflectance on the low wavelength side is suppressed. On the other hand, if it is 700 mass parts or less or 680 mass parts or less, since the coating-film intensity | strength is improved and generation | occurrence | production of a crack etc. is suppressed, it is preferable.

  When the (G) inorganic powder is a combination of rutile type titanium oxide, zirconium oxide, and barium sulfate, the blending ratio (% by mass) of each powder is rutile type titanium oxide 42 to 52%, preferably 47%, Zirconium oxide may be 19-29%, preferably 24%, and barium sulfate 24-34%, preferably 29%. According to the said mixture ratio, the coating film which has the further outstanding light reflectivity is formed.

  Examples of the rutile type titanium oxide include CR-50, CR50-2, CR-57, CR-60, CR-60-2, CR-63, CR-67, CR-58, CR manufactured by Ishihara Sangyo Co., Ltd. -58-2, CR-Super70, CR-80, CR-85, CR-90, CR-90-2, CR-93, CR-95, CR-953, CR-97, UT771, PF-690, PF -691, PF-711, PF-739, PF-740, PC-3, S-305, Sakai Chemical Industry Co., Ltd. SR-1, R-42, R-45M, R-650, R-32, R-5N, GTR-100, GTR-300, R-62N, R-7E, R-44, R-3L, R-11P, R-21, R-25, TCR-52, R-310, D- 918, FTR-700, TR made by Fuji Titanium Industry Co., Ltd. 600, TR-700, TR-750, TR-840, TR-900, manufactured by Takeka Co., Ltd. JR-301, JR-403, JR-405, JR-600A, JR-605, JR-600E, JR-603 , JR-805, JR-806, JR-701, JRNC, JR-800, KA-10, KA-20, KA-30, KR-310, KR-380, KV-200, etc. manufactured by Titanium Industry Co., Ltd. Can be used. These can be used alone or in combination of two or more.

  As the zirconium oxide, for example, EP, SPZ, SOPT, DK-3CH, UEP, RC-100, NNC, WG-8S, etc. manufactured by Daiichi Rare Element Chemical Co., Ltd. can be used. These can be used alone or in combination of two or more.

  As barium sulfate, Sakai Chemical Industry Co., Ltd. B-30, B-31, B-32, B-33, B-34, B-35, B-35T etc. can be used, for example. These can be used alone or in combination of two or more.

  Examples of talc include MS-P, MS, SWE, SW, SSS, NTL, L-1, K-1, LG, P-2, P-3, P-4, manufactured by Nippon Talc Co., Ltd. P-6, P-8, C-31, etc. can be used. These can be used alone or in combination of two or more.

  As the mica, for example, mica / product names A-11, SJ-005, SJ-010 manufactured by Yamaguchi Mica Industry Co., Ltd. can be used. These can be used alone or in combination of two or more.

  As silicon dioxide, for example, manufactured by Denki Kagaku Kogyo Co., Ltd. and product names FB-5DC, FB-3SDC, FB-5SDX, FB-3SDX, FB-1SDX, SFP-20M, SFP-30M, and aluminum oxide, Electrochemical Industry Co., Ltd. product names DAM-03, DAM-05, DAM-10, DAW-03, DAW-05, DAW-10, ASFP-30, and the like can be used.

  As zinc oxide, for example, Hakusuikku Co., Ltd. product name F-1, F-2, F-3 etc. can be used. These can be used alone or in combination of two or more. Examples of magnesium oxide include Iwatani Chemical Industry Co., Ltd., product names MTK-30, MJ-30, Kyowa Chemical Industry Co., Ltd., product names Kyowa Mag Series Kyowa Mug 150, Kyowa Mug 30, and Kyowa Mug MF Series MF. -150, MF-30, Pyroxuma series 5301, 5301K, 3320, 500-04R, etc. can be used. These can be used alone or in combination of two or more.

<(H) Organic solvent>
The (H) organic solvent is not particularly limited, and is used for the purpose of adjusting the viscosity of the composition or controlling the physical properties of the coating film, and a known organic solvent can be used.
Examples of the (H) organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, Glycol ethers such as propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate and Esters such as esterified products of the above glycol ethers; ethanol, propanol, ethylene Recall, alcohols such as propylene glycol; may be mentioned petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, a petroleum solvent or the like, such as solvent naphtha; octane, aliphatic hydrocarbons such as decane. These solvents can be used alone or as a mixture of two or more.

  The blending amount of the (H) organic solvent is (A) a carboxyl group-containing (meth) acrylate having no aromatic ring, the (B) (meth) acryl compound, the (D) epoxy compound, and the (G). The total amount of the inorganic powder is 5 to 30 parts by mass, preferably 10 to 20 parts by mass with respect to 100 parts by mass. The purpose of use of the organic solvent is not only to make the alkali-developable photocurable / thermosetting solder resist composition easy to apply, but also to form a film by drying and to bring the photomask into contact with the coating film. This is because a contact-type exposure method is used.

<Other ingredients>
Furthermore, a known sensitizer, thermal polymerization inhibitor, thickener, antifoaming agent, leveling agent, surface conditioner, coupling agent, flame retardant aid and the like can be used as necessary.

  The alkali-developable photocurable / thermosetting solder resist composition can be provided in a liquid or paste form.

  The alkali-developable photocurable / thermosetting solder resist composition is adjusted to a viscosity suitable for the coating method by diluting with an (H) organic solvent, if necessary. This is applied to a printed wiring board on which a circuit is formed by a method such as a screen printing method, a curtain coating method, a spray coating method, or a roll coating method, and an organic solvent contained in the composition at a temperature of 70 to 90 ° C., for example. A tack-free coating film can be formed by evaporating and drying. Then, the said metal base circuit board is obtained by exposing with active energy rays, such as ultraviolet rays (300-450 nm etc.) selectively through a photomask, and developing an unexposed part with a dilute alkaline aqueous solution, and forming a resist pattern. be able to. The dilute alkaline aqueous solution used here is generally 0.5 to 5% by weight sodium carbonate aqueous solution, but other alkaline aqueous solutions can also be used. Examples of other dilute alkaline aqueous solutions include alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, and the like. As an irradiation light source for exposure, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used. In addition, a laser beam can also be used as an actinic beam.

  A solder resist coating film can be formed by further thermally curing the coating film thus obtained at about 100 to 200 ° C.

  It turned out that the soldering resist film formed using the said soldering resist composition has a high reflectance.

<Metal base circuit board>
Furthermore, by providing a white film using the alkali development type photocurable / thermosetting solder resist composition, it is possible to obtain a metal base circuit board that does not require a light reflecting sheet.

  FIG. 1 is a cross-sectional view for explaining a configuration of the metal base circuit board in an embodiment of the present invention. The metal base circuit board has a white film 4 having a high reflectance on the metal base circuit board composed of the metal foil 1, the insulating layer 2 and the circuit 3, and the white alkali development type photo-curable / thermo-curable solder resist. The LED package 5 is formed by using a composition, and a plurality of LED packages 5 are bonded and mounted by solder bonding portions 6 or the like.

  The metal base circuit board is characterized in that a white film formed using the white alkali-developable photocurable / thermosetting solder resist composition of the present invention has a high reflectance, and is visible at 400 to 800 nm. It is preferable to have a reflectance of 85% or more with respect to the light region, and in a more preferable embodiment, a reflectance of 85% or more with respect to 460 nm (blue), 525 nm (yellow), and 620 nm (red).

  The metal base circuit board has the above-described configuration, the insulating layer has a thermal conductivity of 1 to 4 W / mK, and a withstand voltage between the conductor circuit and the metal foil is 1.5 kV or more, preferably 2 kV. It has high heat dissipation and withstand voltage characteristics as described above, and efficiently dissipates the heat generated from the LED light source to the back side of the metal base circuit board and further dissipates it to the outside. Decreasing the luminous efficiency of the LED can be suppressed by reducing the heat storage and reducing the temperature rise of the LED. For this reason, it is possible to provide a bright and long-life backlight together with the effect of the high reflectance white film 4 having a light reflection function.

  As the metal foil 1, copper and copper alloy, aluminum and aluminum alloy, iron and stainless steel having good thermal conductivity can be used. Moreover, as thickness of the said metal foil 1, a thing of 9 micrometers or more and 400 micrometers or less can be used. If the thickness of the metal foil 1 is 9 μm or more, the rigidity of the metal base circuit board is reduced, so that it is not suitable for actual use. If the thickness is 400 μm or less, the thickness is reduced and useful for miniaturization and thinning. It is.

  The thickness of the insulating layer 2 is preferably 80 μm or more and 200 μm or less. If it is 80 μm or more, electric insulation can be secured, and if it is 200 μm or less, heat dissipation can be sufficiently achieved, and it can contribute to miniaturization and thickness reduction.

  Although the said insulating layer 2 uses a thermosetting resin normally, an epoxy resin, a phenol resin, a silicone resin, an acrylic resin etc. can be used as a thermosetting resin. Among them, the main component is a bifunctional epoxy resin and a polyaddition type curing agent, which will be described later, which are excellent in bonding strength and insulation between the metal foil 1 and the circuit 3 in a cured state while containing inorganic powder. Those are preferred. As the polyaddition type curing agent, acid anhydrides and phenols excellent in mechanical and electrical properties are preferable, and the active hydrogen equivalent is 0.8 equivalent to the epoxy equivalent of the epoxy resin contained in the thermosetting resin. It is preferable to add so as to be ˜1 times in order to ensure the mechanical and electrical properties of the insulating layer 2.

  Epoxy resins include bifunctional epoxy resins bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, resorcinol diglycidyl ether, hexahydrobisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, nero Those using pentyl glycol diglycidyl ether, phthalic acid diglycidyl ester, dimer acid diglycidyl ester or the like are desirable.

  As the polyaddition type curing agent, acid anhydrides such as phthalic anhydride, tetrahydromethyl phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, methyl nadic anhydride, and phenol novolak as phenols are desirable.

  Further, a curing catalyst may be added to accelerate the curing reaction between the epoxy resin and the polyaddition type curing agent. The curing catalyst is preferably an imidazole type, such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl. -4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 2-phenyl-4,5-dihydroxy Methylimidazole, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1') ] -Ethyl-s-triazine, 1-cyanomethyl-2-methylimidazole It is preferred. The amount added may be arbitrarily changed in order to obtain a desired curing rate.

  The chloride ion concentration in the thermosetting resin constituting the insulating layer 2 is preferably 1000 ppm or less, and more preferably 500 ppm or less. If the chloride ion concentration in the curable resin composition is 1000 ppm or less, the migration of ionic impurities hardly occurs at high temperature and under direct current voltage, and the decrease in electrical insulation is suppressed.

  The inorganic powder contained in the insulating layer 2 is preferably one having electrical insulation and good thermal conductivity. For example, silica, alumina, aluminum nitride, silicon nitride, boron nitride, or the like is used. The insulating layer 2 preferably contains 25-50% by volume of a thermosetting resin. In addition, the content of the inorganic powder in the insulating layer 2 is preferably 50 to 75% by volume, and the particle size of the inorganic powder includes two types having an average particle size of 0.6 to 2.4 μm and 5 to 20 μm. It is preferable. By mixing coarse particles having a large average particle diameter and fine particles having a small average particle diameter, it becomes possible to achieve higher filling than when each of them is used alone, and good thermal conductivity can be obtained. Moreover, there are particle shapes such as crushed, spherical and scale-like. If the inorganic powder content is 50% by volume or less, it is difficult to obtain the thermal conductivity necessary for a circuit board for a backlight using an LED package, and if it is 75% or more, the insulating material becomes highly viscous and insulated. Coating of the material becomes difficult, and problems of mechanical properties and electrical properties are likely to occur. Further, the sodium ion concentration in the inorganic powder is preferably 500 ppm or less, and more preferably 100 ppm or less. If the concentration of sodium ions in the inorganic powder exceeds 500 ppm, the migration of ionic impurities may occur at high temperatures and under DC voltage, and the electrical insulation properties may tend to decrease.

  The thickness of the circuit 3 is preferably 9 μm or more and 140 μm or less. If the thickness is 9 μm or more, the function as a circuit can be sufficiently achieved. If the thickness is 140 μm or less, the thickness is excessively increased and it is difficult to reduce the size and thickness. There is nothing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by an Example.

  Table 1 shows the blending amounts of Examples 1 to 5 and Comparative Examples 1 and 2. The numbers inside indicate weight (grams).

CYCLOMER ACAZ251: manufactured by Daicel Cytec Co., Ltd. AGOR4120: manufactured by Osaka Organic Chemical Industry Co., Ltd. AC-SQ: terminal acryloyl group silsesquioxane derivative manufactured by Toagosei Co., Ltd. Light ester HO: 2-hydroxyethyl methacrylate Kyoeisha Chemical Co., Ltd. FA-513M: Tricyclodecyl methacrylate manufactured by Hitachi Chemical Co., Ltd. Deconal acrylate DA722: Acrylic acid modified product of hexahydrophthalic acid diglycidyl ester EA-5521: 1,6 manufactured by Nagase ChemteX Corporation -Hexanediol glycidyl ether acrylate Shin Nakamura Chemical Co., Ltd. Light acrylate DPE-6A: Dipentaerythritol hexaacrylate Kyoeisha Chemical Co., Ltd. Servenus B0134: Alicyclic epoxy resin Die Cell Chemical Industry Co., Ltd. Celoxide 2021P: Alicyclic Epoxy Resin Daicel Chemical Industries, Ltd. YX-8000: Hydrogenated Bisphenol A Type Liquid Epoxy Resin Japan Epoxy Resin Co., Ltd. YX-4000H: Tetramethylbiphenol Type Solid Epoxy resin Made by Japan Epoxy Resin Co., Ltd. CR-90: Rutile type titanium oxide Made by Ishihara Sangyo Co., Ltd. EP: Zirconium oxide Made by Daiichi Rare Element Chemical Industry Co., Ltd. B-30: Barium sulfate Made by Sakai Chemical Industry Co., Ltd. SFP-20M: silicon dioxide manufactured by Denki Kagaku Kogyo Co., Ltd. P-3: talc manufactured by Nippon Talc Co., Ltd. H-320: aluminum hydroxide manufactured by Showa Denko Co., Ltd. Darocur TPO: 2,4,6-trimethylbenzoyldiphenylphos Fin oxide Ciba Japan Co., Ltd. DICY7: Dicyandiamide Di Hap-5 Epoxy Resin Co., Ltd. HN-5500: 3 or 4-methyl-hexahydrophthalic anhydride Hitachi Chemical Co., Ltd. TBZ: 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole Shikoku Kasei Kogyo Co., Ltd. ) TMSOX: 3-ethyl (trimethoxysilylpropoxymethyl) oxetane manufactured by Toagosei Co., Ltd. KS-66: manufactured by Shin-Etsu Chemical Co., Ltd. BYK-300: manufactured by Big Chemie Japan Co., Ltd.

  Each component was blended and stirred according to the blending amounts shown in Table 1, and then dispersed and kneaded using three rolls to prepare a high reflectance alkali-developable photocurable / thermosetting solder resist composition.

  The prepared compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were applied on the metal base circuit board shown below so that the film thickness after curing was 20 to 25 μm by the screen printing method.

  The metal base circuit board is a 35 μm thick copper foil on a bisphenol A type epoxy resin (Japan Epoxy Resin, “EP-828”), and a phenol novolak (Dainippon Ink Chemical Industries, “TD-”) as a curing agent. 2131 "), and crushed coarse particles of silicon dioxide having an average particle size of 1.2 μm (manufactured by Tatsumori Co., Ltd.,“ A-1 ”) and crushed coarse particles of silicon dioxide having an average particle size of 10 μm ( “5X” manufactured by Tatsumori Co., Ltd.) is combined so that the volume of the insulating layer is 56% by volume (spherical coarse particles and spherical fine particles have a mass ratio of 7: 3), and the thickness after curing is 100 μm. A metal base substrate in which an insulating layer is formed, and then an aluminum foil having a thickness of 200 μm is laminated and the insulating layer is thermally cured by heating, so that the total concentration of sodium ions in the insulating layer is 50 ppm or less. Got. Further, the obtained metal base substrate was obtained by masking a predetermined position with an etching resist and etching the copper foil, and then removing the etching resist to form a copper circuit. At this time, a white coating film is not formed on the LED package mounting portion on the copper circuit.

After applying the solder resist composition, it was dried at 80 ° C. for 30 minutes. Next, UV exposure was performed with an integrated light amount of 400 mJ / cm ^2, the non-exposed portion was removed using a 1% sodium carbonate aqueous solution at 28 ° C. as a developer, and then thermosetting was performed at 150 ° C. for 60 minutes.

  The exposure was performed using an ultraviolet curing apparatus ANUP7324 manufactured by Matsushita Electric Works. The integrated light quantity measurement was performed using a TOPCON UV checker UVR-T1. The film thickness was measured using an overcurrent film thickness meter EDY-1000 manufactured by Sanko Electronic Laboratory. The reflectance was measured using a spectrocolorimeter CD100 manufactured by Yokogawa M & C.

  The solder resist composition was evaluated as follows. The reflectance of the coating film after exposure and curing and the coating film in a state treated at 260 ° C. for 1 minute as a heat resistance test were measured. In addition, the reflectance measured the reflectance of the coating-film part provided on the copper circuit which shows a lower reflectance than on an insulating layer. The evaluation results are shown in Table 2.

<Experimental considerations>
As is clear from Table 2, in the examples using the composition of the present invention, rutile type titanium oxide, zirconium oxide and barium sulfate, highly transparent acrylic compounds and alicyclic epoxy resins are used as inorganic powders. Thus, it can be seen that the film is excellent as a solder resist composition having a reflectance of 85% or more and a high reflectance even after film formation and after a heat resistance test.

  In the above, it demonstrated based on the Example of this invention. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

  The highly reflective alkali-developable photocurable / thermosetting solder resist composition of the present invention and a metal base circuit board using the same form a white film with high reflectivity on the surface of the metal base board on which the LED package is mounted. Therefore, it has a light reflection function with a configuration similar to that of a normal printed circuit board. For this reason, the reflected light of the LED light source can be supplied to the liquid crystal part without using an expensive light reflecting sheet. Moreover, the man-hour at the time of liquid-crystal backlight manufacture can also be reduced, it is efficient, and it is very useful industrially as a metal base circuit board for LED.

It is sectional drawing for demonstrating the structure of the metal base circuit board which concerns on one Embodiment of this invention.

Explanation of symbols

1 Metal Foil 2 Insulating Layer 3 Circuit 4 White Film 5 LED Package 6 Solder Joint

Claims (13)

  (A) Carboxyl group-containing (meth) acrylate having no aromatic ring, (B) (meth) acryl compound, (C) photopolymerization initiator, (D) epoxy compound, and (E) for thermosetting A white alkali-developable photocurable / thermosetting solder resist composition comprising a curing agent, (F) a curing catalyst for thermosetting, (G) an inorganic powder, and (H) an organic solvent. object.   The inorganic powder (G) contains rutile type titanium oxide, barium sulfate, zirconium oxide, talc, mica, silicon dioxide, zinc oxide, magnesium oxide or aluminum oxide alone or in combination of two or more. The white alkali-developable photocurable / thermosetting solder resist composition according to claim 1.   2. The white alkali-developable photocurable heat of claim 1, wherein the inorganic powder (G) contains rutile titanium oxide, barium sulfate, and zirconium oxide alone or in combination of two or more. A curable solder resist composition.   2. The white alkali-developable photocurable / thermosetting solder according to claim 1, wherein the inorganic powder (G) contains rutile type titanium oxide, barium sulfate, and zirconium oxide in a combination of two or more. Resist composition.   The blending amount of the (G) inorganic powder is 100 parts by mass of the total of the (A) carboxyl group-containing (meth) acrylate having no aromatic ring, the (B) acrylic compound, and the (D) epoxy compound. The white alkali-developable photocurable / thermosetting solder resist composition according to claim 1, wherein the composition is 350 parts by mass or more and 700 parts by mass or less.   The white alkali-developable photocurable / thermosetting solder resist according to any one of claims 1 to 5, wherein the (B) (meth) acrylic compound contains a terminal acryloyl group silsesoxane derivative. Composition.   The white alkali-developable photocurable / thermosetting property according to any one of claims 1 to 6, wherein the reflectance is 85% or more at 460 nm, 525 nm and 620 nm of visible light. Solder resist composition.   In the metal base circuit board which formed the insulating layer on the metal foil and formed the circuit on the insulating layer, the white layer according to any one of claims 1 to 7 on the insulating layer and the circuit A metal base circuit board obtained by forming a solder resist film using an alkali developing type photo-curable / thermosetting solder resist composition.   The metal base circuit board according to claim 8, wherein the insulating layer has a thermal conductivity of 1 W / mK or more and 4 W / mK or less.   The metal base circuit board according to claim 8, wherein the insulating layer contains an acid anhydride or a phenol.   The metal base circuit board according to any one of claims 8 to 9, wherein the insulating layer contains a bifunctional epoxy resin.   The metal base circuit board according to claim 11, comprising an acid anhydride or a phenol such that an active hydrogen equivalent is 0.8 times or more and 1 time or less with respect to an epoxy equivalent of the bifunctional epoxy resin.   The insulating layer contains 25% by volume or more and 50% by volume or less of a thermosetting resin, the balance has two average particle sizes of 0.6 μm or more and 2.4 μm or less and 5 μm or more and 20 μm or less, and the shape is spherical, The metal base circuit board according to claim 8, wherein the metal base circuit board is a crushed or scaly inorganic powder.

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