JP5089426B2 - Alkali-developable photocurable / thermosetting solder resist composition and metal base circuit board using the same - Google Patents

Description

  The present invention relates to an 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. Hereinafter, the light emitting diode (LED) is referred to as LED. 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

  However, conventionally, a printed circuit board for mounting an LED package for a direct type backlight does not have a light reflecting function. Therefore, when used as a printed circuit board for a backlight, a light reflecting sheet is pasted after mounting the LED package. There was a need. 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 an alkali development type photocurable / thermosetting solder resist composition capable of stably producing a white coating film having a high light reflectance, and at all using the same. The purpose is to provide a new metal-based circuit board.

According to the present invention, there is provided an alkali development type photocurable / thermosetting solder resist composition comprising (A) an organic mixture, (B) an inorganic mixture, and (C) a solvent,
The above-mentioned (A) organic mixture is
(A-1) a carboxyl group and a (meth) acryloyl group-containing polymer;
(A-2) an acrylic compound;
(A-3) a photopolymerization initiator;
(A-4) an epoxy compound;
Containing
The above-mentioned (B) inorganic mixture is
(B-1) a first inorganic substance having a refractive index of 1.4 to 2.5 and an average particle major axis of 1.0 to 20 μm;
(B-2) a second inorganic substance having a refractive index of 2.5 to 3.0 and an average particle length of 0.1 to 0.5 μm;
Containing
(A) / (B) volume% ratio is 70 / 30-30 / 70,
The volume percentage ratio of (B-1) / (B-2) is 5 / 95-80 / 20,
The volume% ratio of (B) / ((A) + (B) + (C)) is 20/100 to 50/100,
The blending amount of the above-mentioned (A-2) acrylic compound is such that the acryloyl group in (A-2) is 0.2 to 5 with respect to 1 mol equivalent of the (meth) acryloyl group in (A-1). It is formulated to be 0 mol equivalent,
The blending amount of the above (A-3) photopolymerization initiator is (A-3) photopolymerization start relative to 1 mol equivalent of (meth) acryloyl group in ((A-1) + (A-2)). The agent is blended to be 0.1 to 5.0 mol equivalent,
The compounding quantity of the above-mentioned (A-4) epoxy compound is the epoxy group in (A-4) with respect to 1 mol equivalent of (carboxyl group + hydroxyl group) in ((A-1) + (A-2)). Formulated to be 0.5-3.0 mol equivalent,
An alkali-developable photocurable / thermosetting solder resist composition is provided.

  According to such a composition, an alkali development type photocurable / thermosetting solder resist composition capable of forming a coating film having high light reflectance with good production stability can be obtained. Therefore, if this solder resist composition is used, a printed circuit board for a backlight including a solder resist film having a high light reflectance, which can be substituted for a light reflecting sheet for increasing the light utilization efficiency of LED, is manufactured. It becomes possible to produce well.

  Further, according to the present invention, a metal foil, an insulating layer provided on the metal foil, a circuit provided on the insulating layer, and the alkali development type photocurable / thermosetting solder resist composition described above There is provided a metal base circuit board comprising an insulating layer and a white film provided on a circuit using an object.

  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, a white solder resist coating film having a high light reflectance can be formed with good production stability. Even if it is not attached, the reflected light can be effectively used only by the metal base circuit board.

<Explanation of terms>
In the present specification, the alkali-developable photocurable / thermosetting solder resist composition is a solder resist film in which a non-exposed portion by masking with a photomask or the like is removed with an alkaline aqueous solution and then cured with heat and / or light. Means a solder resist composition capable of alkali development and capable of photocuring and / or heat curing.

  In this specification, a solder resist composition means a coating material for protecting a portion that does not require soldering when soldering a circuit board or the like.

  In this specification, (meth) acryloyl is a general term for methacryloyl and acryloyl.

  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.

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

<Solder resist composition>

  The alkali development type photocurable / thermosetting solder resist composition according to the present embodiment includes (A) an organic mixture, (B) an inorganic mixture, and (C) a solvent.

  Here, the above-mentioned (A) organic mixture comprises (A-1) a carboxyl group and (meth) acryloyl group-containing polymer, (A-2) an acrylic compound, (A-3) a photopolymerization initiator, (A-4) an epoxy compound.

  The above-mentioned (B) inorganic mixture includes (B-1) a first inorganic substance having a refractive index of 1.4 to 2.5 and an average particle major axis of 1.0 to 20 μm, and (B-2) a refractive index of 2. And a second inorganic substance having an average particle length of 0.1 to 0.5 μm.

  Moreover, about the compounding composition of the above-mentioned (A)-(C), the volume% ratio of (A) / (B) is 70 / 30-30 / 70, (B-1) / (B-2) ) Is 5/95 to 80/20, and (B) / ((A) + (B) + (C)) is 20/100 to 50/100.

  Furthermore, the blending amount of the above-described (A-2) acrylic compound is such that the acryloyl group in (A-2) is 0.2 to 1 mol equivalent of (meth) acryloyl group in (A-1). It is mix | blended so that it may become 5.0 mol equivalent.

  And the compounding quantity of the above-mentioned (A-3) photoinitiator is (A-3) light with respect to 1 mol equivalent of the (meth) acryloyl group in ((A-1) + (A-2)). The polymerization initiator is blended so as to be 0.1 to 5.0 mol equivalent.

  Moreover, the compounding quantity of the above-mentioned (A-4) epoxy compound is (A-4) in (A-4) with respect to 1 mol equivalent of (carboxyl group + hydroxyl group) in ((A-1) + (A-2)). It mix | blends so that it may become 0.5-3.0 mol equivalent of epoxy groups.

  Since the alkali development type photocurable / thermosetting solder resist composition of the present embodiment adopts such a composition, a coating film having a high light reflectance can be formed with good production stability. Therefore, if the alkali-developable photocurable / thermosetting solder resist composition of the present embodiment is used, it can be replaced with a light reflecting sheet for increasing the light utilization efficiency of the LED, and the solder resist film having a high light reflectance. A printed circuit board for a backlight including the above can be manufactured with high manufacturing stability.

<(A) Organic mixture>
The (A) organic mixture used in the present embodiment includes (A-1) a carboxyl group and (meth) acryloyl group-containing polymer, (A-2) an acrylic compound, (A-3) a photopolymerization initiator, (A-4) an epoxy compound. Thus, since the alkali development type photocurable / thermosetting solder resist composition of the present embodiment uses an organic mixture in which four kinds of organic compounds are blended in a well-balanced manner, a coating film with high light reflectance is used. It can be formed with good production stability.

  In addition to (A-1) to (A-4), the (A) organic mixture used in the present embodiment may further contain (A-5) amines and / or acid anhydrides. (A-5) When amines and / or acid anhydrides are used in combination, curing is promoted, which is more preferable.

<(A-1) carboxyl group and (meth) acryloyl group-containing polymer>
The (A-1) carboxyl group and (meth) acryloyl group-containing polymer is not particularly limited, and means a polymer having a carboxyl group and a (meth) acryloyl group in the molecule.

  Examples of the (A-1) carboxyl group- and (meth) acryloyl group-containing polymer include epoxy acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., product name NK Oligo FA-7440 / PGMAc, manufactured by Daicel-Cytec Corporation. Acid group-containing acrylates, product names CYCLOMER (ACA200M, ACA230AA, ACAZ250, ACAZ251, ACAZ300, ACAZ320) and the like can be mentioned. In addition, these are a mixture with (C) solvent, Preferably the product name CYCLOMER by Daicel Cytec Co., Ltd. which does not contain an aromatic ring is good. These carboxyl group and (meth) acryloyl group-containing polymers can be used alone or in combination of two or more.

  The (A-1) carboxyl group and (meth) acryloyl group-containing polymer preferably has a resin acid value in the range of 30 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.

  The weight average molecular weight of the (A-1) carboxyl group- and (meth) acryloyl group-containing polymer is preferably in the range of 5,000 to 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.

<(A-2) Acrylic compound>
(A-2) The acrylic compound is not particularly limited, and means an acrylic compound and / or a methacrylic compound.

  (A-2) Examples of acrylic compounds include mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, Polyhydric alcohols such as tris-hydroxyethyl isocyanurate or polyhydric acrylates of these ethylene oxide or propylene oxide adducts; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxybutyl acrylate; N, N-dimethyl Acrylamides such as acrylamide and N-methylolacrylamide; aminoal such as N, N-dimethylaminoethyl acrylate Acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide or propylene oxide adducts of these phenols; glycidyl ether acrylates such as glycerin diglycidyl ether and trimethylolpropane triglycidyl ether; And / or methacrylates corresponding to the above acrylates, tricyclodecyl methacrylate, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimethacrylate, 1,6-hexanediol glycidyl ether acrylate, tetrahydrofurfuryl acrylate And acrylic acid-modified products of hexahydrophthalic acid diglycidyl esterThese acrylic compounds can be used alone or in combination of two or more.

<(A-3) Photopolymerization initiator>
(A-3) The photopolymerization initiator is not particularly limited, and means a compound capable of initiating polymerization of monomers and oligomers by light irradiation.

  (A-3) Examples of the photopolymerization initiator include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1 1,2-dichloroacetophenone and other acetophenones; benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphine Phosphine oxides such as Ito; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) Aminoalkylphenones such as) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; Anthraquinones such as methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropyl Thioxanthones such as thioxanthone; acetophenone dimethyl ketal; Ketals such as benzyl dimethyl ketal; benzophenones such as benzophenone; or xanthones; various peroxides, titanocene initiators, and the like. These photopolymerization initiators may be used alone or in combination of two or more. Can be used. These photopolymerization initiators include photosensitizers such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. You may use together.

<(A-4) Epoxy compound>
(A-4) The epoxy compound is not particularly limited, and means a compound containing an epoxy ring.

  (A-4) As the epoxy compound, for example, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, phenol novolak type or cresol novolak type epoxy resin or the like, Bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl skeleton epoxy resin, naphthalene skeleton epoxy resin, trisphenol methane type epoxy resin, dicyclopentadiene type epoxy resin glycidyl ether type epoxy resin, cycloaliphatic epoxy resin, Glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, heterocyclic epoxy resin such as triglycidyl isocyanurate having triazine skeleton, bixylenol type epoxy resin, Rate type epoxy resin, glyoxal type epoxy resin, rubber-modified epoxy resins, silicone-modified epoxy resins, such as ε- caprolactone-modified epoxy resin. These epoxy compounds can be used alone or in combination of two or more.

<(A-5) Amines and / or acid anhydrides>
(A-5) The amines and / or acid anhydrides may be amines only, acid anhydrides only, or a mixture of amines and acid anhydrides.

  As such (A-5) amines, known ones 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, lalomine, diaminodiphenylmethane, metaphenyldiamine, diaminodisulfone, polyoxypropylenediamine, polyoxypropylenetriamine, polycyclohexyl Examples thereof include polyamine mixtures and N-aminoethylpiperazine. These amines can be used alone or as a mixture of two or more.

  As such (A-5) acid anhydride, a publicly known thing can be used. Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate), anhydrous Maleic acid, tetrahydromaleic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydro Phthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic acid anhydride, alkylstyrene-maleic anhydride copolymer, polyazeline acid anhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid An acid anhydride etc. can be mentioned. These acid anhydrides can be used alone or as a mixture of two or more.

<(A) Composition of organic mixture>
To repeat, the (A) organic mixture used in this embodiment comprises (A-1) a carboxyl group and (meth) acryloyl group-containing polymer, (A-2) an acrylic compound, and (A-3) light. A polymerization initiator and (A-4) an epoxy compound are contained. Thus, since the alkali development type photocurable / thermosetting solder resist composition of the present embodiment uses an organic mixture in which four kinds of organic compounds are blended in a well-balanced manner, a coating film with high light reflectance is used. It can be formed with good production stability.

  Thus, in the organic mixture which mix | blended four types of organic compounds with sufficient balance, the compounding quantity of (A-2) acrylic compound is (A) with respect to 1 mol equivalent of the (meth) acryloyl group in (A-1). -2) It is preferable to mix | blend so that it may become 0.2-5.0 mol equivalent of acryloyl groups in an acryl-type compound. (A-2) When the acryloyl group in the acrylic compound is 0.2 equivalent or more, photocurability is improved, and pattern formation after exposure and development is facilitated. Conversely, when (A-2) the acryloyl group in the acrylic compound is 5.0 mol equivalent or less, it becomes easy to remove the non-exposed portion of the solder resist composition with an alkaline aqueous solution, and the residual development is easily suppressed. preferable.

  Moreover, the compounding quantity of (A-3) photoinitiator is (A-3) photopolymerization start with respect to 1 mol equivalent of (meth) acryloyl group in ((A-1) + (A-2)). It is preferable to mix | blend so that it may become 0.1-5.0 mol equivalent of agent. (A-3) When the photopolymerization initiator is 0.1 mol equivalent or more, photocurability is improved, and pattern formation after exposure and development is facilitated. Conversely, (A-3) a photopolymerization initiator of 5.0 mol equivalent or less is preferred because the heat discoloration is improved and cracks are hardly generated in the cured coating film.

  And the compounding quantity of (A-4) epoxy compound is contained in (A-4) epoxy compound with respect to 1 mol equivalent of (carboxyl group + hydroxyl group) in ((A-1) + (A-2)). The epoxy group is preferably blended so as to be 0.5 to 3.0 mol equivalent. (A-4) When the epoxy group contained in the epoxy compound is 0.5 mol equivalent or more, the thermosetting property is improved, and (A-1) carboxyl group and hydroxyl group in the carboxyl group- and (meth) acryloyl group-containing polymer and (A-2) Since the proportion of the carboxyl group and hydroxyl group remaining in the unreacted state in the acrylic compound is reduced, it is preferable because the moisture resistance, electrical properties, solder properties, and chemical resistance of the cured coating film are improved. On the contrary, when the epoxy group contained in the epoxy compound (A-4) is 3.0 mol equivalent or less, it becomes easy to remove the non-exposed portion of the solder resist composition with an alkaline aqueous solution, and the development residue is hardly generated. preferable.

  In addition, as described above, in the (A) organic mixture used in this embodiment, when (A-5) amines and / or acid anhydrides are used in combination, the ink characteristics are improved and the coating film is more uniformly and cleanly applied. A film is formed, and curing is accelerated, which is more preferable. At this time, the compounding amount of (A-5) amine and / or acid anhydride is (A-4) amine equivalent (primary amine + primary amine in amine) with respect to 1 equivalent of epoxy group contained in the epoxy compound. It is preferable to add so that the total of the anhydride equivalents in the (diamine + tertiary amine) and / or acid anhydride is 1 equivalent or less. When it is 1 equivalent or less, heat discoloration resistance and light discoloration resistance are improved, and cracks are less likely to occur in the coating film after curing.

<(B) Inorganic mixture>
The (B) inorganic mixture used in the present embodiment includes (B-1) a first inorganic substance having a refractive index of 1.4 to 2.5 and an average particle major axis of 1.0 to 20 μm, and (B-2) a refractive index. And a second inorganic substance having an average particle length of 0.1 to 0.5 μm. As described above, the alkali development type photocurable / thermosetting solder resist composition of the present embodiment includes (B-1) an inorganic substance having a small refractive index and a large average particle length, and (B-2) a refractive index. Since an inorganic mixture in which two types of inorganic substance having a large average particle length and a small average particle size are mixed in a balanced manner is used, a coating film having high light reflectance can be formed with good production stability. In this way, by mixing coarse particles having a large average particle length and fine particles having a small average particle length, it becomes possible to achieve a higher filling than when each of them is used alone, and the coating properties are reduced by highly filling inorganic particles. Can be suppressed. Further, an inorganic material having a small refractive index tends to have a higher reflectance when the average particle length is larger, and an inorganic material having a larger refractive index tends to have a higher reflectance when the average particle length is smaller. Therefore, it is possible to improve the reflectivity while suppressing a decrease in coating performance by using a mixture of coarse particles having a large average particle length with a specific refractive index within a reasonable range and fine particles having a small average particle length. Thus, it became possible to produce a white solder resist film having a high reflectivity on an exquisite balance of practical composition.

  Moreover, (B) inorganic mixture used for this embodiment is (B-3) an inorganic substance with a refractive index of 1.4 to 2.5 and an average particle length of 0.1 to 0.5 μm as the third inorganic substance. Use in combination is preferable because the reflectance becomes higher.

<(B-1) First inorganic substance>
(B-1) The first inorganic substance is not particularly limited, and has a refractive index of 1.4 (preferably 1.5 or more) to 2.5 (preferably 2.0 or less) and an average particle length of 1.0 to 1.0. A 20 μm white inorganic substance can be used. (B-1) If the refractive index of a 1st inorganic substance is 1.4 or more or 1.5 or more, there exists a tendency for a reflectance not to fall with an inorganic substance with an average particle major axis of 20 micrometers or less, and it is preferable. On the other hand, if the refractive index of the (B-1) first inorganic substance is 2.5 or less or 2.0 or less, the reflectance tends not to decrease even when an inorganic substance having an average particle major axis of 1 μm or more is used, which is preferable. .

  (B-1) As an inorganic substance having a refractive index of 1.4 to 2.5 and an average particle length of 1.0 to 20 μm, for example, silicon dioxide (refractive index 1.5), barium sulfate (refractive index 1.6). , Magnesium oxide (refractive index 1.7), aluminum oxide (refractive index 1.8), zinc oxide (refractive index 2.0), talc (refractive index 1.6), mica (refractive index 1.6). These can be used alone or in combination of two or more.

  Specifically, large particle barium sulfate manufactured by Sakai Chemical Industry Co., Ltd., product name BMH-60, plate-like barium sulfate, product name A, HF, H, HM, HL, HP, HG, Nippon Talc Co., Ltd. Product talc and product names MS-P, MS, SWE, SW, SSS, NTL, L-1, K-1, LG, P-2, P-3, P-4, P-6, P- 8, C-31, mica manufactured by Yamaguchi Mica Industry Co., Ltd., product names A-11, SJ-005, SJ-010, zinc oxide manufactured by Sakai Chemical Industry Co., Ltd., product names LPZINC-2, LPZINC- 3, LPZINC-11, Magnesium oxide manufactured by Kamishima Chemical Co., Ltd., product name Starmag P, HP-30, HP-30A, Magnesium oxide / Product names manufactured by Kyowa Chemical Industry Co., Ltd. Kyowa Mag 30, Kyowa Mag 150, Pyroxuma 5Q, manufactured by Denki Kagaku Kogyo Co., Ltd. Silicon dioxide, product names FS-5DC, FS-3DC, FB-5DC, FB-3SDC, FB-5SDX, FB-1SDX, aluminum oxide manufactured by Denki Kagaku Kogyo Co., Ltd. Product names DAM-03, DAM-05, DAM-10, DAW-03, DAW-05, DAW-10, ASFP-30, etc. can be used.

<(B-2) Second inorganic substance>
(B-2) The second inorganic substance is not particularly limited, and a white inorganic substance having a refractive index of 2.5 to 3.0 and an average particle major axis of 0.1 to 0.5 μm can be preferably used. . (B-2) If the refractive index of a 2nd inorganic substance is 2.5 or more and 3.0 or less, since there exists a tendency for a reflectance to become high with an average particle major axis of 0.1-0.5 micrometer, it is preferable.

  (B-2) As a white inorganic substance having a refractive index of 2.5 to 3.0 and an average particle length of 0.1 to 0.5 μm, rutile type titanium oxide (refractive index of 2.7) can be mentioned. Specifically, CR-50, CR50-2, CR-57, CR-60, CR-60-2, CR-63, CR-67, CR-58, CR-58-2 manufactured by Ishihara Sangyo Co., Ltd. , 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, SR-1, R-42, R-45M, R-650, R-32, R-5N, manufactured by Sakai Chemical Industry Co., Ltd. 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-600, TR-700 manufactured by Fuji Titanium Industry Co., Ltd. R-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, JR, KA-10, KA-20, KA-30, KR-310, KR-380, KV-200 manufactured by Titanium Industry Co., Ltd. may be used. it can. These can be used alone or in combination of two or more.

<(B-3) Third inorganic substance>
(B-3) The third inorganic substance is not particularly limited, and an inorganic substance having a refractive index of 1.4 to 2.5 and an average particle major axis of 0.1 to 0.5 μm can be suitably used. Although the reflectance is low when used alone, the reflectance increases when used in combination with (B-1) and (B-2).

  As such (B-3) inorganic substance having a refractive index of 1.4 to 2.5 and an average particle length of 0.1 to 0.5 μm, a publicly known one can be used. For example, silicon dioxide (refractive index 1.5), barium sulfate (refractive index 1.6), magnesium oxide (refractive index 1.7), aluminum oxide (refractive index 1.8), zinc oxide (refractive index 2.0). These may be used alone or in combination of two or more.

  Specifically, barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. Product names B-30, B-31, B-32, B-33, B-34, B-35, B-35T, Hakusuikku Co., Ltd. Zinc oxide, product name F-1, magnesium oxide manufactured by Iwatani Chemical Industry Co., Ltd., product names MTK-30, MJ-30, silicon dioxide manufactured by Denki Kagaku Kogyo Co., Ltd., product name SFP-20M, electrochemistry Aluminum oxide manufactured by Kogyo Co., Ltd., product name ASFP-20, and the like can be used.

  The particle major axis of (B-1) the first inorganic substance, (B-2) the second inorganic substance, and (B-3) the third inorganic substance contained in the (B) inorganic mixture used in the present embodiment is These can be directly observed and measured with an optical microscope, a scanning electron microscope, or the like. The particle major axis is perpendicular to the parallel line that determines the minor axis (distance between two parallel lines at the shortest distance in contact with the contour in the plan view of the particle) in the plan view of the particle with the particle placed on a plane. This is the distance between two parallel lines of direction (Revised 2nd edition, Powder Theory and Application, issued on May 12, 1979, published by Maruzen Co., Ltd.). Here, the average particle major axis is an average value obtained by measuring the major axis of 100 or more particles.

<(B) Composition of inorganic mixture>
Again, the (B) inorganic mixture used in the present embodiment includes (B-1) a first inorganic substance having a refractive index of 1.4 to 2.5 and an average particle length of 1.0 to 20 μm, and (B -2) a second inorganic substance having a refractive index of 2.5 to 3.0 and an average particle major axis of 0.1 to 0.5 μm. As described above, the alkali development type photocurable / thermosetting solder resist composition of the present embodiment includes (B-1) an inorganic substance having a small refractive index and a large average particle length, and (B-2) a refractive index. Since an inorganic mixture in which two types of inorganic substance having a large average particle length and a small average particle size are mixed in a balanced manner is used, a coating film having high light reflectance can be formed with good production stability.

  Thus, in the inorganic mixture which mix | blended two types of inorganic compounds with sufficient balance, it is preferable that the volume% ratio of (B-1) / (B-2) is 5 / 95-80 / 20. When the volume ratio of (B-1) in the total volume of (B-1) and (B-2) is 5% or more, a high content of the inorganic substance (B) can be easily added to the solder resist composition. . In addition, even when an inorganic substance is blended in a high amount, a decrease in ink characteristics can be suppressed, and the solder resist composition can be applied to the substrate uniformly and cleanly. When the volume ratio of (B-1) is 80% or less, the solvent (C) of the solder resist composition to be described later is prevented from being cracked in the coating film after volatile drying or after curing, and the coating film Since it suppresses that the adhesiveness of a board | substrate falls, a coating-film defect reduces.

  Moreover, although it repeats, (B) inorganic mixture used for this embodiment is a refractive index of 1.4-2.5 and average particle | grain major axis 0.1-0. It is preferable to use an inorganic substance having a thickness of 5 μm because the reflectance becomes higher. At this time, it is more preferable that the volume ratio of (B-1) / (B-2) / (B-3) is 5/95/0 (excluding 0) to 80/5/15. Of the total volume of (B-1), (B-2), and (B-3), it is preferable that the volume percentage of (B-3) exceeds 0 because the reflectance is further increased. Moreover, if the volume% of (B-3) is 15% or less among the above-mentioned total volume, it can suppress that the coating film after hardening peels from a board | substrate.

<(C) Solvent>
(C) A solvent is not specifically limited, It uses for the objective of adjustment of the viscosity in the soldering resist composition of this embodiment, the physical property control of a coating film, etc., and can use a well-known organic solvent.

  Examples of the solvent (C) include methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol. Glycol ethers such as monoethyl ether; esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate and esterified products of the above glycol ethers; alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; Aliphatic hydrocarbons such as octane and decane; methyl ethyl ketone, cyclohexano Ketones such as; may be used petroleum naphtha, hydrogenated petroleum naphtha, solvent naphtha, petroleum solvents such as petroleum ether: toluene, xylene, aromatic hydrocarbons such as tetramethyl benzene. These solvents can be used alone or as a mixture of two or more.

<Overall blending composition>
Again, in the alkali development type photocurable / thermosetting solder resist composition of the present embodiment, the total composition of (A) an organic mixture, (B) an inorganic mixture, and (C) a solvent. Since the balance of the three main constituents in is good, a coating film with high light reflectance can be formed with good production stability.

  That is, in the alkali development type photocurable / thermosetting solder resist composition of the present embodiment, the volume% ratio of (A) organic mixture / (B) inorganic mixture is 70/30 to 30/70, that is, the solvent ( C) It is preferable that the volume% of the inorganic substance (B) in the coating film (A) + (B) after volatile drying and curing is 30 to 70. When (B) in the cured coating is 30% by volume or more, a satisfactory reflectance is obtained, and when it is 70 or less, the cured coating is difficult to peel off from the substrate.

  Furthermore, in the alkali development type photocurable / thermosetting solder resist composition of this embodiment, the volume% ratio of (B) / ((A) + (B) + (C)) is 20/100 to 50. / 100 is preferable. If the volume percentage of (B) in ((A) + (B) + (C)) is 20% or more, the thickness of the coating film can be easily controlled, and satisfactory reflectance can be obtained. If so, the viscosity of the solder resist composition does not become too high and can be applied uniformly and cleanly to the substrate.

<Other ingredients>
Furthermore, in the alkali development type photocurable / thermosetting solder resist composition of the present embodiment, a curing accelerator, a thermal polymerization inhibitor, a thickener, an antifoaming agent, a leveling agent, and a coupling agent are added as necessary. A flame retardant aid or the like can be added within a range where the total volume% of (B-1), (B-2), and (B-3) in the cured coating film is 30 to 70.

<Formation of solder resist film>
The alkali-developable photocurable / thermosetting solder resist composition of this embodiment is preferably provided in a liquid or paste form. This is because the coating performance on the metal base circuit board is excellent in such a form.

  The alkali-developable photocurable / thermosetting solder resist composition of the present embodiment can be adjusted to a viscosity suitable for the coating method by diluting with a solvent or the like if necessary. This is applied to a metal base substrate 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. Next, a tack-free coating film can be formed by evaporating and drying the solvent (C) contained in the composition at a temperature of 70 to 90 ° C., for example.

  Then, the metal base circuit board of the present invention is formed by selectively exposing through a photomask with active energy rays such as ultraviolet rays (300 to 450 nm, etc.) and developing the unexposed portion with a dilute alkaline aqueous solution to form a resist pattern. Can be obtained. As an irradiation light source for exposure used here, 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. Moreover, a laser beam etc. can be used as an actinic ray. The dilute alkaline aqueous solution used here is generally 0.5 to 5% by weight sodium carbonate aqueous solution, but other alkalis such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate. An aqueous solution of sodium silicate, ammonia, amines, etc. can also be used.

  The coating film thus obtained is further thermally cured at 100 to 200 ° C. to form a solder resist coating film.

  It turned out that the soldering resist film formed by the above methods using the soldering resist composition of this embodiment has a high reflectance as shown in the Example mentioned later.

<Metal base circuit board>
Furthermore, by providing a white film using the alkali developing photocurable / thermosetting solder resist composition of the present embodiment, a metal base circuit board that does not require a light reflecting sheet can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is an example of a metal base circuit board according to the present embodiment. In the metal base circuit board according to the present embodiment, the white film 4 having a high reflectance is formed on the metal base circuit board including the metal foil 1, the insulating layer 2, and the circuit 3, and the alkali development type photocuring property / It is formed using a thermosetting solder resist composition, and a plurality of LED packages 5 are joined and mounted by solder joints 6 or the like. The metal base circuit board of the present embodiment is characterized in that a white film formed using the alkali development type photocurable / thermosetting solder resist composition of the present embodiment has a high reflectance, and is 400 to 800 nm. In the preferred embodiment, it has a reflectance of 80% or more for 460 nm (blue), 525 nm (yellow) and 620 nm (red).

  That is, in summary, the metal base circuit board of the present embodiment includes the metal foil 1, the insulating layer 2 provided on the metal foil 1, the circuit 3 provided on the insulating layer 2, and the present embodiment. It is a metal base circuit board provided with the white film 4 provided on the insulating layer 2 and the circuit 3 using the alkali development type photocurable and thermosetting solder resist composition of the form.

  The metal base circuit board of the present embodiment has the above-described configuration, and the insulating layer 2 has a thermal conductivity of 1 to 4 W / mK, and the withstand voltage between the conductor circuit 3 and the metal foil 1 is 1. It has high heat dissipation and withstand voltage characteristics of 5 kV or more, desirably 2 kV or more, and heat generated from the LED light source is efficiently dissipated to the back side of the metal base circuit board, and further to the outside, By reducing the heat storage of the LED package mounting circuit board and reducing the temperature rise of the LED, it is possible to suppress a decrease in the light emission efficiency 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.

  In the present embodiment, as the metal foil 1, copper and copper alloy, aluminum and aluminum alloy, iron, stainless steel, and the like having good thermal conductivity can be used. Moreover, as thickness of the metal foil 1, the 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 lowered, so that it is not suitable for actual use. If the thickness is 400 μm or less, the thickness increases and is useful for miniaturization and thinning. .

  In the present embodiment, 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.

  For the insulating layer 2, a thermosetting resin is usually used, and as the thermosetting resin, an epoxy resin, a phenol resin, a silicone resin, an acrylic resin, or the like can be used. Among them, what contains a bifunctional epoxy resin (described later) and a polyaddition type curing agent, which are excellent in bonding strength and insulation between the metal foil 1 and the circuit 3 in the cured state, while containing an inorganic filler, are the main components. preferable. 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.

  Epoxy resins include bifunctional epoxy resins such as 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 above-described epoxy resin and 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 -Dihydroxymethylimidazole, 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 filler contained in the insulating layer 2 is preferably an electrically insulating and heat conductive material, and for example, silica, alumina, aluminum nitride, silicon nitride, boron nitride or the like is used. The content of the inorganic filler in the insulating layer 2 is preferably 50 to 75% by volume, and the particle size of the inorganic filler contains 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 filler content is 50% by volume or less, it is difficult to obtain the thermal conductivity required 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. Moreover, it is preferable that the sodium ion concentration in an inorganic filler is 500 ppm or less, and it is more preferable that it is 100 ppm or less. If the sodium ion concentration in the inorganic filler is 500 ppm or less, the migration of ionic impurities is suppressed even at high temperatures and under direct voltage, and the electrical insulation can be prevented from being lowered.

  The thickness of the circuit 3 is preferably 9 μm or more and 140 μm or less, and if it is 9 μm or more, the function as a circuit can be sufficiently achieved, and if it is 140 μm or less, the thickness increases excessively, making it difficult to reduce the size and thickness. Nor.

  <Effect>

  The alkali-developable photocurable / thermosetting solder resist composition according to the present embodiment and a metal base circuit board using the same are manufactured and stable by the present inventors. As a result of diligent investigation to form with good properties, the composition of the organic mixture / inorganic mixture contained in the solder resist composition, the refractive index, particle size, and content of the inorganic substance contained in the inorganic mixture within a predetermined range It has been found out by adjusting that a white solder resist coating film having a high reflectance can be formed with good production stability.

  That is, the solder resist composition according to the present embodiment is a solder resist composition in which the blending composition of the organic mixture / inorganic mixture, the refractive index, the particle size, and the content of the inorganic substance are adjusted within a predetermined range, and exposure After that, by removing the non-exposed part by masking with photomask etc. with alkaline aqueous solution and then curing with heat and light, it is possible to form a white solder resist coating film with high reflectivity with good manufacturing stability. This is a mold photocurable / thermosetting solder resist composition.

  Further, the metal base circuit board according to the present embodiment is a metal base circuit board for a direct type backlight using an LED as a non-ultraviolet irradiation light source and a light reflection sheet. Specifically, the above-described solder resist composition is used. It is a high reflectivity white metal base circuit board having a high reflectivity white coating film instead of the obtained light reflection sheet.

  That is, the metal base circuit board according to the present embodiment is 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, and the above-described alkali development type is formed on the insulating layer and the circuit. It is a metal base circuit board provided with a white film using a photocurable / thermosetting solder resist composition. In the metal base circuit board according to the present embodiment, preferably, the reflectances of visible light of the white film at 460 nm, 525 nm, and 620 nm are all 80 to 95%. In the metal base circuit board according to the present embodiment, preferably, the thermal conductivity of the insulating layer is 1 to 4 W / mK. In the metal base circuit board according to the present embodiment, preferably, the insulating layer contains a bifunctional epoxy resin.

Further, the metal base circuit board according to the present embodiment, preferably, the insulating layer comprises an acid anhydride or a phenol, 0.8 times active hydrogen equivalent of the epoxy equivalent of the difunctional epoxy resin To contain acid anhydrides or phenols. Furthermore, in the metal base circuit board according to the present embodiment, preferably, the insulating layer contains 25 to 50% by volume of a thermosetting resin, and the balance is an average of two types of 0.6 to 2.4 μm and 5 to 20 μm. An inorganic filler having a particle size and having a spherical shape, crushed shape, or scale shape is included.

  According to the metal base circuit board according to the present embodiment, a white solder resist coating film having a high reflectance can be formed, and even if the light reflection sheet is not attached after LED mounting, only the metal base circuit board can be formed. The reflected light can be used effectively. In other words, in addition to the conventional printed circuit board function of mounting electronic components, a circuit board having a new function of light reflection function can be obtained. When the metal base circuit board of the present embodiment having a light reflection function is used as a printed circuit board for a direct type backlight using LEDs, for example, a high-reflectance white coating film on the metal base circuit board Can be used as a light reflecting sheet, so that an expensive light reflecting sheet does not have to be used, and the number of man-hours and necessary members for manufacturing the backlight can be reduced, leading to cost reduction.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  For example, in the above embodiment, the circuit board provided with the white film using the alkali development type photocurable / thermosetting solder resist composition of the present embodiment is a metal base circuit board. It is not intended to be limited to circuit boards.

  That is, the alkali development type photocurable / thermosetting solder resist composition of the present embodiment is the same even when applied to a normal circuit board in which a prepreg or the like is laminated on a non-metal core substrate. A white solder resist coating film having a high reflectance can be formed. Therefore, even in this case, when used as a printed circuit board for a direct type backlight using an LED, a high reflectance white coating film on a normal circuit board may be used as a light reflecting sheet. Therefore, it is not necessary to use an expensive light reflecting sheet, and the number of man-hours and necessary members at the time of manufacturing the backlight can be reduced, leading to cost reduction.

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

  For Examples 1 to 13 and Comparative Examples 1 to 16, each component was blended and stirred according to the blending amount (parts by mass) shown in Tables 1 to 4, and then dispersed and kneaded using three rolls to develop the alkali. A photocurable / thermosetting solder resist composition was prepared.

  The prepared compositions of Examples 1 to 13 and Comparative Examples 1 to 16 were applied on the metal base circuit board shown below so that the film thickness after curing was about 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 oxide having an average particle size of 1.2 μm (manufactured by Tatsumori,“ A-1 ”) and crushed coarse particles of silicon oxide 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. An insulating layer is then formed, and then a 200 μm thick aluminum foil is laminated and heated to thermally cure the insulating layer, thereby obtaining a metal base substrate having a sodium ion concentration of 50 ppm or less in the entire inorganic filler in the insulating layer. It was. 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.

(A-1) -1: CYCLOMER ACA200M manufactured by Daicel Cytec Co., Ltd., solid content 47-50 wt%, solvent propylene glycol monomethyl ether, resin density 1.2 g / cm ³ , resin acid value 106-121, weight average molecular weight 10000-17000, double bond equivalent (acryloyl group equivalent) 450
(A-1) -2: Daicel Cytec Co., Ltd. CYCLOMER ACAZ251, solid content 44.5-46.5 wt%, solvent dipropylene glycol monomethyl ether, density 1.1 g / cm ³ , resin density 1.2 g / cm ³ , resin acid value 58 to 74, weight average molecular weight 10000 to 18000, double bond equivalent (acryloyl group equivalent) 380
(A-1) -3: CYCLOMER ACA230AA manufactured by Daicel Cytec Co., Ltd., solid content 51 to 55 wt%, solvent propylene glycol monomethyl ether, density 1.1 g / cm ³ , resin density 1.2 g / cm ³ , resin acid 33-47, double bond equivalent (acryloyl group equivalent) 450

(A-2) -1: dipentaerythritol hexaacrylate, double bond equivalent (acryloyl group equivalent) 96.3, density 1.155 g / cm ³ , molecular weight 578

(A-3) -1: Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Ciba Japan Co., Ltd. IRGACURE819 Molecular weight 419
(A-3) -2: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one Ciba Japan Co., Ltd. IRGACURE907 density 1.2 g / cm ³ , molecular weight 279
(A-3) -3: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Ciba Japan Co., Ltd. DAROCUR TPO Molecular weight 350

  (A-4) -1: Hydrogenated bisphenol A type epoxy resin, Japan Epoxy Resin Co., Ltd. YX-8000 epoxy equivalent 205, density 1.2

(A-5) -1: Melamine molecular weight 126.12, density 1.57 g / cm ³ , 3 equivalents of primary amine, 3 equivalents of tertiary amine in one molecule, amine equivalent 21
(A-5) -2: Dicyandiamide molecular weight 84.08, density 1.4 g / cm ³ , 1 equivalent of primary amine, 2 equivalents of secondary amine, 1 equivalent of tertiary amine, 1 amine equivalent 21
(A-5) -3: 3or4-methyl-hexahydrophthalic anhydride, HN5500 manufactured by Hitachi Chemical Co., Ltd., density 1.16 g / cm ³ , molecular weight 168, acid anhydride equivalent 168

(B-1) -1: Large particle barium sulfate, manufactured by Sakai Chemical Industry Co., Ltd. BMH-60 Average particle major axis 6 μm, density 4.5 g / cm ³
(B-1) -2: Plate-like barium sulfate, manufactured by Sakai Chemical Industry Co., Ltd. A Average particle major axis 6 μm, density 4.5 g / cm ³

(B-2) -1: Titanium oxide, CR-90 manufactured by Ishihara Sangyo Co., Ltd. Average particle major axis 0.25 μm, density 4.2 g / cm ³

(B-3) -1: Barium sulfate, Sakai Chemical Industry Co., Ltd. Variace B-30 Average particle major axis 0.3 μm, density 4.5 g / cm ³

(C) -1: Dipropylene glycol monomethyl ether density 0.95 g / cm ³
Antifoaming agent: Shin-Etsu Chemical Co., Ltd. KS-66 density 1.01 g / cm ³

The solder resist composition was evaluated as follows.
Application property: Application performance of a solder resist composition to a substrate.
Developability: After coating, dried at 80 ° C. for 30 minutes, exposed to ultraviolet light, and then visually observed for removal of non-exposed areas and 1% of sodium-carbonate aqueous solution at 28 ° C. in 1% aqueous solution.
Cured coating film appearance: Visual observation of cured coating film appearance (presence of cracks, coating film surface roughness, etc.).
Adhesion: Visual observation of the adhesion between the cured coating and the substrate.
◎: Good ○: Almost good △: Somewhat bad ×: Bad

  Further, the reflectance of the cured coating film formed satisfactorily was 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 Tables 1 to 4.

  As can be seen from Tables 1 to 4, in Examples 1 to 13, by using an inorganic substance having a specific refractive index and a specific average particle major axis in combination, it can be applied even if a high content of the inorganic substance is blended. It can be seen that it is excellent in properties, developability, appearance of cured coating film and adhesion, and is excellent as a solder resist composition having high reflectivity.

  In the above, this invention was demonstrated based on the Example. 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 alkali-developable photocurable / thermosetting solder resist composition of the present invention and the metal base circuit board using the same form a white coating film having a high reflectance 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 of an example of the metal base circuit board based on this invention.

Explanation of symbols

1 Metal foil 2 Insulating layer 3 Circuit 4 White film
5 LED package 6 Solder joint

Claims (11)

(A) an organic mixture, (B) an inorganic mixture, and (C) a solvent, an alkali development type photocurable / thermosetting solder resist composition,
Said (A) organic mixture is
(A-1) a carboxyl group and a (meth) acryloyl group-containing polymer;
(A-2) an acrylic compound;
(A-3) a photopolymerization initiator;
(A-4) an epoxy compound;
Containing
The (B) inorganic mixture is
(B-1) has a mean particle diameter 1.0 to 20, first made of barium sulfate, silicon dioxide, aluminum oxide, zinc oxide, magnesium oxide, talc, from one or two or more combinations selected from mica Of inorganic substances,
A second inorganic material composed of titanium oxide having a (B-2) average particle diameter 0.1 to 0.5 [mu] m,
Containing
(A) / (B) volume% ratio is 70 / 30-30 / 70,
The volume percentage ratio of (B-1) / (B-2) is 5 / 95-80 / 20,
The volume% ratio of (B) / ((A) + (B) + (C)) is 20/100 to 50/100,
The blending amount of the (A-2) acrylic compound is such that the acryloyl group in (A-2) is 0.2 to 5.0 mol with respect to 1 mol equivalent of the (meth) acryloyl group in (A-1). It is formulated to be equivalent,
The blending amount of the (A-3) photopolymerization initiator is (A-3) photopolymerization initiator with respect to 1 mol equivalent of the (meth) acryloyl group in ((A-1) + (A-2)). Is blended to be 0.1 to 5.0 mol equivalents,
The compounding amount of the (A-4) epoxy compound is 0 epoxy group in (A-4) with respect to 1 mol equivalent of (carboxyl group + hydroxyl group) in ((A-1) + (A-2)). .5 to 3.0 mol equivalent,
Alkali development type photocurable / thermosetting solder resist composition. (B) the inorganic mixture, (B-3) having a mean particle diameter 0.1 to 0.5 [mu] m, barium sulfate, silicon dioxide, aluminum oxide, zinc oxide, alone is selected from magnesium oxide or two or more A third inorganic material comprising a combination of
The alkali development according to claim 1, wherein the volume percentage ratio of (B-1) / (B-2) / (B-3) is from 5/95/0 (excluding 0) to 80/5/15. Type photo-curable and thermosetting solder resist composition.   The alkali-developable photocurable / thermosetting solder resist composition according to claim 1 or 2, wherein the (A) organic mixture further contains (A-5) amines and / or acid anhydrides. The (B-1) first inorganic substance is an inorganic substance composed of one or a combination of two or more selected from barium sulfate, silicon dioxide, aluminum oxide, zinc oxide, magnesium oxide, talc and mica,
The (B-2) second inorganic substance is rutile titanium oxide,
The (B-3) third inorganic substance is an inorganic substance consisting of barium sulfate, silicon dioxide, aluminum oxide, zinc oxide, magnesium oxide, or a single or a combination of two or more. An alkali development type photo-curable / thermosetting solder resist composition according to claim 1. Metal foil,
An insulating layer provided on the metal foil;
A circuit provided on the insulating layer;
A white film provided on the insulating layer and the circuit using the alkali development type photocurable / thermosetting solder resist composition according to any one of claims 1 to 4,
A metal-based circuit board comprising:   The metal base circuit board according to claim 5, wherein the white film has a reflectance at 460 nm, 525 nm, and 620 nm of 80% or more.   The metal base circuit board according to claim 5 or 6, wherein the insulating layer has a thermal conductivity of 1 to 4 W / mK.   The metal base circuit board according to claim 5, wherein the insulating layer contains a bifunctional epoxy resin.   The metal base circuit board according to claim 8, wherein the insulating layer further contains an acid anhydride or a phenol. The epoxy equivalent weight of the difunctional epoxy resin, so that the active hydrogen equivalent weight is 0.8 to 1 times, containing an acid anhydride or said phenol, the metal base circuit board according to claim 9 .   The insulating layer contains 25 to 50% by volume of a thermosetting resin, the balance has two types of average particle lengths of 0.6 to 2.4 μm and 5 to 20 μm, and the shape is spherical, crushed, or scaly The metal base circuit board according to any one of claims 5 to 10, comprising a shaped inorganic filler.

Images