Alkaline developing type resin composition, photocurable dry film and cured product thereof, and printed wiring board formed using the same

Abstract

The present invention provides an alkali-developable resin composition capable of forming a solder resist layer having excellent adhesion and cold-heat shock resistance, a photocurable dry film thereof, a cured product thereof, and a printed circuit board formed using the same. The alkali-developable resin composition is characterized by containing (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) a glass powder, (D) a compound having two or more ethylenically unsaturated groups in one molecule, and (E) an inorganic filler, the (E) inorganic filler including talc, the (C) glass powder including, in terms of weight %, SiO2: 60 to 65 %, Fe2O3: 0.01 to 0.02 %, Al2O3: 14 to 20 %, CaO: 6 to 9 %, MgO: 1 to 2 %, B2O3: 8 to 12 %, the (C) glass powder having a Mohs hardness of less than 6.5.

Description

[0001] This application is a divisional application of the application filed on December 27, 2023, with application number 202380017216.6, entitled "Alkaline developing resin composition, its photocurable dry film and cured product, and printed circuit board formed therefrom". Technical Field

[0002] This invention relates to alkaline developable resin compositions suitable for forming solder resist layers, etc., of which photocurable dry films and cured products are particularly related to alkaline developable resin compositions capable of forming solder resist layers with excellent adhesion and resistance to thermal shock, photocurable dry films and cured products thereof, and printed circuit boards. Background Technology

[0003] Currently, in the formation of solder resist layers (solder resist films) on some consumer printed circuit boards and almost all industrial printed circuit boards, alkaline developable solder resists are used, which are exposed to ultraviolet light to form an image and then fully cured by heat and / or light irradiation (primary curing). Furthermore, in semiconductor devices used in transportation vehicles such as automobiles, trains, ships, and airplanes, there is a trend towards using solder resists designed for high-reliability electronic materials as solder resists on printed circuit boards.

[0004] However, conventional alkaline-developable solder resist inks typically exhibit poor resistance to thermal shock and cracking due to thermal expansion and contraction, resulting in low reliability in response to environmental temperature variations. Furthermore, from the perspectives of protecting copper circuits and aesthetics, the solder resist layer must possess excellent adhesion. While using talc as a filler can improve cracking, adhesion remains poor. Alternatively, using a combination of talc and silica as fillers may meet the thermal shock resistance requirements for automotive-grade solder resist inks, but adhesion is still insufficient.

[0005] For example, the fillers used in the photocurable solder resist ink of Patent Document 1 are silica, barium sulfate, and talc. The curable resin composition for the solder resist layer of Patent Document 2 contains a carboxyl-containing resin, a thermosetting component, a flame retardant, and an ion scavenger. The ion scavenger is a mixture of a hydrotalcite-based ion scavenger and an ion scavenger other than hydrotalcite. The inorganic filler used is aluminum hydroxide. The curable resin composition of Patent Document 3, used as a permanent mask for printed circuit boards, comprises: a resin containing olefinic unsaturated groups and carboxyl groups within its molecule, a photopolymerization initiator, a photopolymerizable monomer, titanium oxide surface-treated with alumina, barium sulfate and / or talc, and an organic solvent. The UV-curable liquid photosensitive solder resist ink of Patent Document 4 describes barium sulfate, talc, or silica as fillers.

[0006] Patent Document 1: CN114716868A

[0007] Patent Document 2: CN108137791A

[0008] Patent Document 3: CN101798432A

[0009] Patent Document 4: CN106380929A Summary of the Invention

[0010] The problem the invention aims to solve

[0011] The purpose of this invention is to provide an alkaline developable resin composition capable of forming a solder resist layer with excellent adhesion and resistance to thermal shock, a photocurable dry film thereof and its cured product, and a printed circuit board.

[0012] Solution for solving the problem

[0013] The inventors conducted repeated and in-depth research to solve the aforementioned problems, and found that the type of filler has a significant impact on resistance to thermal shock. The alkaline developing resin composition described below can solve the above problems, thus completing this invention. The alkaline developing resin composition is characterized by containing (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) glass powder, (D) a compound having two or more vinyl unsaturated groups in one molecule, and (E) an inorganic filler. The (E) inorganic filler contains talc, calculated as a percentage by weight. The (C) glass powder contains SiO2: 60–65%, Fe2O3: 0.01–0.02%, Al2O3: 14–20%, CaO: 6–9%, MgO: 1–2%, and B2O3: 8–12%. The Mohs hardness of the (C) glass powder is less than 6.5.

[0014] That is, the alkaline developing resin composition of the present invention is characterized by containing (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) glass powder, (D) a compound having two or more ethylene unsaturated groups in one molecule, and (E) an inorganic filler, wherein the (E) inorganic filler contains talc, and the (C) glass powder contains SiO2: 60-65%, Fe2O3: 0.01-0.02%, Al2O3: 14-20%, CaO: 6-9%, MgO: 1-2%, B2O3: 8-12%, and the Mohs hardness of the (C) glass powder is less than 6.5.

[0015] In addition, it is preferable to contain other additives (F) besides (B) photopolymerization initiator and (C) glass powder.

[0016] In addition, it is preferred to contain (G) epoxy resin.

[0017] In addition, it is preferred to use an organic solvent containing (H).

[0018] Furthermore, the photocurable dry film of the present invention is characterized in that it is obtained by coating the alkaline developable resin composition onto a carrier film and then drying it.

[0019] Furthermore, the cured product of the present invention is characterized in that it is obtained by photocuring a coating film as follows: a coating film obtained by coating the alkaline developing resin composition onto copper and drying it; or a coating film obtained by coating the alkaline developing resin composition onto a carrier film and drying it, and then laminating the resulting photocurable dry film onto copper.

[0020] Furthermore, the printed circuit board of the present invention is characterized in that it is obtained by photocuring and then thermally curing a coating, wherein the coating is obtained by coating the alkaline developable resin composition onto a substrate having copper circuits and drying it; or by coating the alkaline developable resin composition onto a carrier film and drying it, and then laminating the resulting photocurable dry film onto a substrate having copper circuits.

[0021] The most significant technical feature of the alkaline developing resin composition of the present invention is that it comprises (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) glass powder, (D) a compound having two or more ethylene unsaturated groups in one molecule, and (E) an inorganic filler, wherein the (E) inorganic filler comprises talc, and the (C) glass powder comprises SiO2: 60-65%, Fe2O3: 0.01-0.02%, Al2O3: 14-20%, CaO: 6-9%, MgO: 1-2%, B2O3: 8-12%, and the Mohs hardness of the (C) glass powder is less than 6.5.

[0022] Based on the features of this invention, by combining soft composite glass powder and talc and adjusting their ratio, adhesion can be improved while maintaining excellent thermal shock resistance.

[0023] In contrast, in the prior art, the simultaneous use of talc and barium sulfate as fillers can meet the requirements for thermal shock resistance of solder resist inks, but the adhesion will be poor (e.g., Patent Document 1).

[0024] As described above, through repeated and in-depth research, the inventors discovered that talc, as a filler, exhibits good flexibility and excellent crack resistance in the Temperature Cycle Test (TCT), but its adhesion deteriorates with increasing usage. While glass powder, especially soft composite glass powder, can provide excellent adhesion as a filler, its resistance to thermal shock is insufficient. By using both talc and glass powder as fillers, excellent resistance to thermal shock and adhesion can be maintained simultaneously, thus achieving the aforementioned objective of this invention.

[0025] The effects of the invention

[0026] As described above, the present invention provides an alkaline developable resin composition capable of forming a solder resist layer with excellent adhesion and resistance to thermal shock, a photocurable dry film thereof, and a cured product thereof, as well as a printed circuit board. Attached Figure Description

[0027] Figure 1 Photographs (NG (cracking)) of the solder mask used to evaluate thermal shock resistance in the embodiments are shown.

[0028] Figure 2 To show a photograph of the solder mask used to evaluate thermal shock resistance in the embodiment without cracking (OK (no cracking)).

[0029] Figure 3 This is a schematic diagram (spindle schematic diagram) of the spindle used in evaluating adhesion in the embodiments. Detailed Implementation

[0030] The constituent components of the alkaline developing resin composition of the present invention will be described below.

[0031] The alkaline developing resin composition of the present invention is characterized by containing (C) glass powder and (E) inorganic filler, wherein the (E) inorganic filler contains talc as an essential component, and therefore the (C) glass powder and (E) inorganic filler will be described first.

[0032] (C) Glass powder

[0033] The (C) glass powder used in the alkaline developing resin composition of the present invention refers to a powdered, glassy, ​​amorphous inorganic material, the main component of which is silicon dioxide. Typically, it is produced by sintering inorganic minerals as the main raw material at high temperature.

[0034] As for the glass powder (C) used in the alkaline developing resin composition of the present invention, a soft composite glass powder is preferred from the perspective of further facilitating the achievement of the objectives of the present invention. The glass powder (C) may be untreated or surface-treated.

[0035] The typical composition of the soft composite glass powder is: SiO2: 60-65%, Fe2O3: 0.01-0.02%, Al2O3: 14-20%, CaO: 6-9%, MgO: 1-2%, B2O3: 8-12%. Preferably, the composition is: SiO2: 61-64%, Fe2O3: 0.012-0.019%, Al2O3: 15-19%, CaO: 6.5-8.5%, MgO: 1.1-1.8%, B2O3: 9-11%. More preferably, the composition is: SiO2: 62-63%, Fe2O3: 0.014-0.018%, Al2O3: 16-18%, CaO: 7-8%, MgO: 1.2-1.6%, B2O3: 9.5-10.5%.

[0036] The soft composite glass powder has a Mohs hardness of less than 6.5, preferably in the range of 4.8 to 6.2, and more preferably in the range of 5 to 6.

[0037] The inventors have discovered that, from the perspective of balancing thermal shock resistance and adhesion of the solder resist layer, further blending (C) glass powder while using talc as a filler can significantly improve adhesion while maintaining excellent thermal shock resistance. In this case, a weight ratio of talc to glass powder of 90:10 to 10:90 is suitable, preferably 80:20 to 20:80, more preferably 75:25 to 25:75, and even more preferably 70:30 to 30:70. Thus, an alkaline developable resin composition capable of achieving both excellent thermal shock resistance and adhesion of the solder resist layer can be obtained.

[0038] For the mixing ratio of (C) glass powder, 10 to 90 parts by weight relative to 100 parts by weight of the vinyl ester resin (A) based on solids is suitable, preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight, and even more preferably 40 to 60 parts by weight. Using (C) glass powder within the above range ensures improved adhesion while achieving excellent resistance to thermal shock. Exceeding the above range reduces its properties as a solder resist and is therefore undesirable.

[0039] Commercially available products of flexible composite glass powder include: K10 (manufactured by Suzhou Jinyi New Material Technology Co., Ltd.) and G2C (manufactured by Shanghai Sibico Mining Co., Ltd.).

[0040] (E) Inorganic packing

[0041] In the alkaline developing resin composition of the present invention, the talc used as the inorganic filler (E) is used to improve resistance to thermal shock. The inorganic filler (E) here does not include the glass powder (C) mentioned above, especially the soft composite glass powder.

[0042] The parent rock of talc can be any one of magnesium carbonate, serpentine, silica / silica-alumina, or magnesium sediments, and can be any type of silicate mineral. It can be massive or powdery. Surface treatment is optional. An average particle size of 1.0-20.0 μm is suitable, more preferably 2.0-10 μm, and even more preferably 3.0-8.0 μm. Commercially available products include HD25 manufactured by Pingdu Talc Mining Co., Ltd. in Shandong Province, and LMP-100 manufactured by Fuji Talc Industry Co., Ltd.

[0043] The amount of talc is suitable to be 10 to 90 parts by weight relative to 100 parts by weight of (A) vinyl ester resin based on solid content, preferably 20 to 80 parts by weight, and more preferably 30 to 70 parts by weight. If it is within the above range, adhesion can be improved while ensuring excellent resistance to thermal shock.

[0044] Without affecting the purpose of this invention, other fillers besides talc and the glass powder described above (C), such as silica, may also be incorporated. This silica can be either amorphous or crystalline, or a mixture thereof. Amorphous (fused) silica is particularly preferred. Surface treatment may or may not be performed. This silica typically has a Mohs hardness of 6.5 or higher. An average particle size of 0.1 to 10.0 μm is suitable, more preferably 1.0 to 8.0 μm, and even more preferably 2.0 to 6.0 μm. Commercially available examples of this silica include CS1002 and CS1002A manufactured by Jiangsu Lianrui New Materials Co., Ltd., A-8 manufactured by Sibelco Co., Ltd., SE-40 manufactured by Tokuyama Co., Ltd., MSV25G manufactured by Ryusei, MLV-2114 manufactured by Ryusei, SO-E5 manufactured by ADMATECHS, and SO-E2 manufactured by ADMATECHS.

[0045] (A) Vinyl ester resin

[0046] As the (A) vinyl ester resin in the photocurable and thermocurable resin composition of the present invention, from the perspective of photocurability and developability, a known resin containing an olefinic unsaturated double bond in its molecule can be used. Furthermore, to impart alkali developability, a carboxyl-containing resin having an olefinic unsaturated double bond in its molecule is particularly preferred. Moreover, it is more preferable that the unsaturated double bond is derived from acrylic acid or methacrylic acid or derivatives thereof. As the (A) vinyl ester resin, resins starting from epoxy resins, polyurethane resins having a urethane backbone, copolymer resins having a copolymer structure of unsaturated carboxylic acids, and resins starting from phenolic compounds are preferred. Specific examples of the (A) vinyl ester resin are shown below.

[0047] (1) A vinyl ester resin obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with one or more compounds having unsaturated double bonds;

[0048] (2) A photosensitive vinyl ester resin is obtained by adding olefinic unsaturated groups in the form of side groups to a copolymer of unsaturated carboxylic acids such as (meth)acrylic acid and one or more other compounds with unsaturated double bonds, such as glycidyl methacrylate, 3,4-epoxycyclohexyl methyl methacrylate, and (meth)acryloyl chloride.

[0049] (3) A photosensitive vinyl ester resin obtained by reacting copolymers of compounds with epoxy groups and unsaturated double bonds, such as glycidyl methacrylate and 3,4-epoxycyclohexyl methyl methacrylate, and other compounds with unsaturated double bonds, with unsaturated carboxylic acids such as methacrylic acid, and by reacting polyacid anhydrides with the generated secondary hydroxyl groups.

[0050] (4) A photosensitive vinyl ester resin obtained by reacting a copolymer of anhydrides such as maleic anhydride with unsaturated double bonds and other compounds with unsaturated double bonds with compounds such as 2-hydroxyethyl methacrylate with hydroxyl groups and unsaturated double bonds.

[0051] (5) A vinyl ester resin obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polycarboxylic acid anhydride with the generated hydroxyl group.

[0052] (6) A vinyl ester resin containing hydroxyl and carboxyl groups is obtained by reacting a hydroxyl-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polyacid anhydride, and then reacting a compound with an epoxy group and an unsaturated double bond in one molecule with the generated carboxylic acid.

[0053] (7) A vinyl ester resin obtained by reacting a polyfunctional epoxy compound and an unsaturated monocarboxylic acid with a compound having at least one alcoholic hydroxyl group and one reactive group other than the alcoholic hydroxyl group that reacts with an epoxy group, and with a saturated or unsaturated polyacid anhydride.

[0054] (8) A vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional oxetane compound having at least two oxetane rings in one molecule, and reacting a saturated or unsaturated polycarboxylic acid anhydride with a primary hydroxyl group in the resulting modified oxetane resin; and

[0055] (9) For the carboxyl-containing resin obtained by reacting unsaturated monocarboxylic acid with polyfunctional epoxy resin and then reacting it with polybasic acid anhydride, a vinyl ester resin is obtained by further reacting it with a compound having one oxopropane ring and one or more olefinic unsaturated groups.

[0056] (10) A vinyl ester resin is obtained by reacting a bifunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polycarboxylic acid anhydride with the generated hydroxyl group.

[0057] The vinyl ester resins of (2), (5), (7), and (9) are particularly preferred substances among these examples.

[0058] It should be noted that in this specification, (meth)acrylate is a term used collectively to refer to acrylates, methacrylates and mixtures thereof, and the same applies to other similar expressions.

[0059] The aforementioned (A) vinyl ester resin has multiple free carboxyl groups on the side chains of the main polymer chain, and therefore can be developed using a dilute alkaline aqueous solution.

[0060] Furthermore, the acid value of the vinyl ester resin in (A) is preferably in the range of 40 to 200 mg KOH / g, and more preferably in the range of 45 to 120 mg KOH / g. When the acid value of (A) vinyl ester resin is less than 40 mg KOH / g, it is difficult to develop with alkali. On the other hand, when it exceeds 200 mg KOH / g, it will promote the dissolution of the exposed area by the developer. Therefore, the lines become finer than required, and sometimes the exposed and unexposed areas are dissolved and peeled off by the developer indiscriminately, making it difficult to draw a normal resist pattern. Therefore, it is not preferred.

[0061] Furthermore, the weight-average molecular weight of the aforementioned (A) vinyl ester resin varies depending on the resin skeleton, and is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. When the weight-average molecular weight is less than 2,000, the coating onto the substrate and the non-stick properties after drying sometimes deteriorate. In addition, the moisture resistance of the coating after exposure sometimes worsens, the amount of film produced during development decreases, and the resolution deteriorates significantly. On the other hand, when the weight-average molecular weight exceeds 150,000, the developability sometimes deteriorates significantly, and the storage stability deteriorates.

[0062] (A) The ideal amount of vinyl ester resin in the formulation is 20-60% by mass of the total composition based on solids, preferably 25-50% by mass. (A) If the amount of vinyl ester resin in the formulation is less than the range described above, the coating strength decreases, which is not preferred. On the other hand, if the amount is more than the range described above, the viscosity of the composition increases or the coatability decreases, which is also not preferred.

[0063] (B) Photopolymerization initiator

[0064] There are no particular limitations on the photopolymerization initiator used in the alkaline developable resin composition of the present invention, as long as it is a photopolymerization initiator commonly used in alkaline developable resin compositions.

[0065] As photopolymerization initiators, known substances can be used, including: benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoin and its alkyl ethers; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4-(1-tert-butyldioxy-1-methylethyl)acetophenone, and other acetophenones; 2-methylanthraquinone, 2-pentylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, etc. Anthraquinones; thioxanthones such as isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzoyl dimethyl ketal; benzophenones such as 4-(1-tert-butyldioxy-1-methylethyl)benzophenone and 3,3',4,4'-tetra(tert-butyldioxycarbonyl)benzophenone; and xanthones, etc.

[0066] In addition, oxime ester photopolymerization initiators with oxime ester groups, alkyl phenyl ketone photopolymerization initiators, α-aminoacetophenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanium ceramsite photopolymerization initiators, phosphate ester photopolymerization initiators, etc., can also be used as photopolymerization initiators.

[0067] Commercially available oxime ester-based photopolymerization initiators include Irgacure OXE01 and Irgacure OXE02 manufactured by BASF Japan, and N-1919 and NCI-831 manufactured by ADEKA CORPORATION. Photopolymerization initiators with two oxime ester groups within the molecule are preferred; specifically, oxime ester compounds with a carbazole ring structure can be cited as examples.

[0068] Commercially available alkyl phenyl ketone photopolymerization initiators include α-hydroxyalkyl phenyl ketones such as Omnirad 184, Omnirad 1173, Omnirad 2959, and Omnirad 127 manufactured by IGM Resins B.V.

[0069] As α-aminoacetophenone-based photopolymerization initiators, specific examples include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone. Commercially available products include Omnirad 907, Omnirad 369, and Omnirad 379 manufactured by IGM Resins BV.

[0070] Examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and acylphosphine oxide photopolymerization initiators with three or more functional groups. These acylphosphine oxide photopolymerization initiators can be photopolymerization initiators having three or more acylphosphine oxide skeletons in one molecule, and can be represented by the following formula (I).

[0071]

[0072] In the formula,

[0073] A represents a single bond, O, S, or NR independently of each other. 3 ;

[0074] G is a multifunctional compound (core) G-(AH) m+n The residues, where AH each represent an alcohol group, an amino group, or a thiol group;

[0075] Both m and n are integers, and m+n is an integer between 3 and 10;

[0076] m is an integer between 3 and 8;

[0077] R1 and R2 are independently C1-C 18 Alkyl, C6-C 12 aryl and C5-C 12 The cycloalkyl group is either not broken or is cleaved by the following groups: one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups, or R1 and R2 are independently five- to six-membered heterocyclic groups containing oxygen and / or nitrogen and / or sulfur atoms, wherein the aforementioned groups are optionally substituted by aryl, alkyl, aryloxy, alkoxy, heteroatom and / or heterocyclic groups.

[0078] R2 can be R1-(C=O)-;

[0079] Y is either O or S;

[0080] R3 is hydrogen or a C1-C4 alkyl group;

[0081] The photopolymerization initiator of formula (I) does not contain photocurable olefinic unsaturated groups.

[0082] Preferably, in formula (I), m+n is an integer between 3 and 8, more preferably an integer between 3 and 6. For example, in formula I, m is an integer between 3 and 6, more preferably an integer between 3 and 5.

[0083] In equation (I), when A is oxygen, G-(AH) m+n It is a polyhydroxy (multi-hydroxyl) compound, selected from the group consisting of monomeric polyols, oligomeric polyols, polymeric polyols, and mixtures thereof. When A is sulfur, G-(AH) m+n It is a polythiol compound. In formula (I), when A is nitrogen, G-(AH) m+n It can be a linear or branched polyamine. When A is a mixture of oxygen and / or nitrogen and / or sulfur, G-(AH) m+n Compounds containing different functional groups, such as compounds containing amino and hydroxyl groups. The residue G- suitable for implementation of this invention does not contain a photocurable olefinic unsaturated group. When A is a single bond, G- is G-(AH) as listed above. m+n The residues after removing hydroxyl and / or amino and / or thiol groups.

[0084] G-(AH) is preferred. m+n It has a number average molecular weight of 1500 or less, more preferably 800 or less, and even more preferably 500 or less.

[0085] When n is not 0, the compound of formula (I) has an alcoholic free radical and / or an amino and / or a thiol group.

[0086] Table 1 shows representative trifunctional or higher acylphosphine-based photopolymerization initiators included in formula (I). Among these, PI-3, PI-4, PI-10, PI-11, PI-12, PI-14, and PI-17 are particularly preferred. By including such trifunctional or higher acylphosphine-based photopolymerization initiators, cured products with suppressed exhaust and superior insulation reliability can be obtained.

[0087] Table 1

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Such acylphosphine photopolymerization initiators with three or more functions can be manufactured, for example, by the method described in Japanese Patent No. 6599446.

[0096] Commercially available photopolymerization initiators based on acylphosphine oxides include Omnirad TPO manufactured by IGM Resins, Omnirad 819 manufactured by IGM Resins BV, and Omnipol TP.

[0097] Specifically, examples of the aforementioned titanium-based photopolymerization initiators include bis(cyclopentadienyl)-diphenyltitanium, bis(cyclopentadienyl)-titanium dichloride, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrolo-1-yl)phenyl)titanium. Commercially available examples include Omnirad 784 manufactured by IGM Resins B.V.

[0098] For the mixing ratio of these photopolymerization initiators (B), 0.01 to 30 parts by weight relative to 100 parts by weight of the vinyl ester resin (A) based on solids is suitable, preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight. If the amount of photopolymerization initiator used is less than the range described above, the photocurability of the composition deteriorates; on the other hand, if the amount is excessive, its properties as a solder resist are reduced, which is not preferred.

[0099] It should be noted that in this specification, polymer is a term used collectively to refer to homopolymers, copolymers and mixtures thereof, and the same applies to other similar expressions.

[0100] (D) Compounds having two or more vinyl unsaturated groups in one molecule

[0101] The compound (D) used in the alkaline developing resin composition of the present invention, having two or more vinyl unsaturated groups in one molecule, is a compound that, through photocuring by irradiation with active energy rays, renders the aforementioned (A) vinyl ester resin insoluble in alkaline aqueous solutions, or contributes to the insolubility of the aforementioned vinyl ester resin in alkaline aqueous solutions. Specific examples of such compounds include:

[0102] Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and other hydroxyalkyl acrylates;

[0103] Monoacrylates or diacrylates of diols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol;

[0104] Acrylamides such as N,N-dimethylacrylamide, N-hydroxymethylacrylamide, and N,N-dimethylaminopropylacrylamide;

[0105] N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropyl acrylate, and other aminoalkyl acrylates;

[0106] Polyols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, trihydroxyethyl isocyanurate, or their ethylene oxide adducts or propylene oxide adducts, and polyacrylates;

[0107] Acrylates such as phenoxy acrylates, bisphenol A diacrylates, and ethylene oxide adducts or propylene oxide adducts of these phenols;

[0108] Acrylates of glycidyl ethers such as diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate;

[0109] And melamine acrylate, and at least one of the methacrylates corresponding to the above acrylates.

[0110] Furthermore, examples include: epoxy acrylate resins formed by reacting multifunctional epoxy resins such as cresol phenolic varnish-type epoxy resins with acrylic acid, and epoxy urethane acrylate compounds formed by further reacting the hydroxyl groups of the epoxy acrylate resin with hydroxy acrylates such as pentaerythritol triacrylate and half urethane compounds such as isophorone diisocyanate.

[0111] The amount of compound (D) having two or more vinyl unsaturated groups per molecule is preferably 5 to 100 parts by weight relative to 100 parts by weight of the aforementioned vinyl ester resin (A) based on solids content. When the amount of such compound (D) is less than 5 parts by weight relative to 100 parts by weight of the aforementioned vinyl ester resin (A), the photocurability of the resulting alkaline-developable resin composition decreases, making it difficult to form patterns through alkaline development after irradiation with active energy rays, which is therefore undesirable. On the other hand, when the amount exceeds 100 parts by weight, the solubility in alkaline aqueous solutions decreases, and the cured coating becomes brittle, which is also undesirable.

[0112] (F) Other additives

[0113] As described above, other additives in this invention refer to additives other than (B) photopolymerization initiator and (C) glass powder.

[0114] Examples of such additives include: commonly known colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, carbon black, and naphthalene black; commonly known thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrogallol, and phenothiazine; commonly known thickeners such as micronized silica, organobentonite, and montmorillonite; at least one type of defoamer and leveling agent from organosilicon, fluorine, and polymeric systems; binding agents from imidazole, thiazole, and triazole systems; silane coupling agents; antioxidants from phenol, phosphorus, and sulfur systems; hindered amine light stabilizers; and dispersants.

[0115] The mixing ratio of such (F) other additives is suitable to be 0.01% by weight or more and 20% by weight or less of the total amount of the alkaline developing resin composition. When it is less than 0.01% by weight, the corresponding effect cannot be obtained sufficiently, and when it exceeds 20% by weight, the printability and hardness of the alkaline developing resin composition deteriorate, so it is not preferred.

[0116] (G) Epoxy Resin

[0117] To impart heat resistance, it is preferred that the alkaline developing resin composition used in this invention is a compound of epoxy resin having at least two epoxy groups in its molecules, i.e., a multifunctional epoxy resin (G).

[0118] Commercially available products include, for example: Bisphenol A type epoxy resins such as jER828, jER834, jER1001, jER1004 manufactured by Mitsubishi Chemical Corporation; EPICLON 840, 850, 850S, 1050, 2055 manufactured by DIC Corporation; EPOTOTE YD-011, YD-013, YD-127, YD-128 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.; DER317, DER331, DER661, DER664 manufactured by Dow Chemical Company; and Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 manufactured by Sumitomo Chemical Industries Co., Ltd. (all trade names); bisphenol A type epoxy resins such as jERYL903 manufactured by Mitsubishi Chemical Corporation; and EPICLON 152 and EPICLON manufactured by DIC Corporation. 165. Brominated epoxy resins such as EPOTOTE YDB-400 and YDB-500 manufactured by NIPPONSTEEL Chemical & Material Co., Ltd., DER542 manufactured by Dow Chemical Company, and Sumi-Epoxy ESB-400 and ESB-700 manufactured by Sumitomo Chemical Industry Co., Ltd. (all trade names); brominated epoxy resins such as jER152 and jER154 manufactured by Mitsubishi Chemical Co., Ltd., DEN431 and DEN438 manufactured by Dow Chemical Company, EPICLONN-730, EPICLON N-770, and EPICLON N-865 manufactured by DIC Corporation; and EPOTOTE manufactured by NIPPON STEEL Chemical & Material Co., Ltd. YDCN-701, YDCN-704, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000 manufactured by Nippon Kayaku Co., Ltd., Sumi-Epoxy ESCN-195X, ESCN-220 manufactured by Sumitomo Chemical Co., Ltd., and NIPPON STEELC Chemical & Material Co., Ltd.The company manufactures YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A, and DIC Corporation's EPICLON N-680, N-690, N-695 (all trade names) phenolic varnish-type epoxy resins; DIC Corporation's EPICLON 830, Mitsubishi Chemical Corporation's JER807, and NIPPON STEEL Chemical & Material Co., Ltd.'s EPOTOTEYDF-170, YDF-175, YDF-2004 (all trade names) bisphenol F type epoxy resins; NIPPON STEEL Chemical & Material Co., Ltd. Hydrogenated bisphenol A type epoxy resins such as EPOTOTEST-2004, ST-2007, ST-3000 (trade names) manufactured by Co., Ltd., and YX8034 manufactured by Mitsubishi Chemical Corporation; glycidylamine type epoxy resins such as jER604 manufactured by Mitsubishi Chemical Corporation, EPOTOTE YH-434 manufactured by NIPPONSTEEL Chemical & Material Co., Ltd., and Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Industry Co., Ltd.; hydantoin type epoxy resins; and CELLOXIDE manufactured by Daicel Corporation. 2021P and other (trade names) alicyclic epoxy resins; YL-933 manufactured by Mitsubishi Chemical Corporation, EPPN-501 and EPPN-502 manufactured by Nippon Kayaku Co., Ltd. (all trade names) trihydroxyphenylmethane type epoxy resins; YL-6056, YX-4000, YL-6121 and other bixylenol or biphenol type epoxy resins or mixtures thereof manufactured by Mitsubishi Chemical Corporation; EBPS-200 and ADE manufactured by Nippon Kayaku Co., Ltd. KACORPORATION manufactures EPX-30, DIC manufactures EXA-1514 (trade name) and other bisphenol S type epoxy resins; Mitsubishi Chemical manufactures jER157S (trade name) and other bisphenol A phenolic varnish type epoxy resins; Mitsubishi Chemical manufactures jERYL-931 (trade name) and other tetrahydroxyphenyl ethane type epoxy resins; Nissan Chemical Industries manufactures TEPIC (trade name) and other heterocyclic epoxy resins; Nippon Oil Company manufactures BRENMAR DGT and other diglycidyl phthalate resins; NIPPON STEEL Chemical & Material Co., Ltd. manufactures ZX-1063 and other tetraglycidyl dimethyl ethane resins; NIPPON STEELC Chemical & Material Co., Ltd.This includes, but is not limited to, epoxy resins containing a naphthalene skeleton, such as ESN-190, ESN-360, HP-4032, EXA-4750, and EXA-4700 manufactured by DIC; glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M manufactured by Nippon Oil Company; furthermore, copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; CTBN-modified epoxy resins (such as YR-102 and YR-450 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), etc. These epoxy resins can be used alone or in combination of two or more.

[0119] The content of (G) epoxy resin is preferably 10 to 100 parts by weight relative to 100 parts by weight of (A) vinyl ester resin based on solids, more preferably 20 to 90 parts by weight, and even more preferably 30 to 80 parts by weight.

[0120] (H) Organic solvents

[0121] The organic solvent (H) that can be used in the alkaline developing resin composition of the present invention can be used to synthesize the aforementioned vinyl ester resin (A), prepare the composition, or adjust the viscosity for coating on a substrate or carrier film.

[0122] Examples of such organic solvents include: ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. More specifically, these include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolves, methyl cellosolves, butyl cellosolves, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ethers, naphtha, hydrogenated naphtha, and solvent naphtha. The above-mentioned organic solvents can be used alone or in the form of a mixture of two or more.

[0123] When using the alkaline developable resin composition of the present invention to form the solder resist layer of a printed circuit board, the viscosity is adjusted to be suitable for the coating method as needed, and then applied to a printed circuit board with a pre-formed circuit by methods such as screen printing, curtain printing, spraying, or roller coating. A non-sticky coating can be formed by drying at a temperature of approximately 60 to 100°C, for example, as needed. Then, by selectively exposing the unexposed areas with active light through a photomask with a predetermined exposure pattern, an anti-etching pattern can be formed by developing the unexposed areas with an alkaline aqueous solution. Furthermore, by heating to a temperature of approximately 140 to 180°C for thermal curing, for example, the curing reaction of the epoxy resin (G) and the polymerization of the vinyl ester resin (A) can be promoted, thereby improving various properties of the obtained anti-etching coating, such as adhesion, thermal shock resistance, heat resistance, solvent resistance, acid resistance, moisture resistance, PCT resistance, adhesion, and electrical properties.

[0124] As the alkaline aqueous solution used in the above-mentioned development process, alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc., can be used. Furthermore, as the irradiation light source for photocuring, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, semiconductor lasers, solid-state lasers, xenon lamps, or metal halide lamps are suitable.

[0125] In addition to being applied directly as a liquid to a substrate having copper circuitry, the alkaline developer-type resin composition of the present invention can also be used as a photocurable dry film obtained by pre-coating the alkaline developer-type resin composition onto a carrier film and drying it. The following illustrates the use of the alkaline developer-type resin composition of the present invention in the form of a photocurable dry film.

[0126] The photocurable dry film has a structure consisting of a carrier film, a resin layer, and a peelable cover film, which may be used as needed, stacked sequentially. The resin layer is obtained by coating the carrier film with the alkaline developer-type resin composition of the present invention and drying it. After the resin layer is formed on the carrier film, the cover film is stacked on top of it to obtain the photocurable dry film.

[0127] As the carrier film, thermoplastic films such as polyester films with a thickness of 2–150 μm can be used. The resin layer is formed by uniformly coating an alkaline developing resin composition onto the carrier film with a thickness of 10–150 μm using a doctor blade coater, lip coater, comma coater, or film coater, and then drying it. As the cover film, polyethylene films, polypropylene films, etc., can be used. Cover films with a lower adhesion strength to the resin layer than the adhesion strength between the carrier film and the resin layer are preferred.

[0128] The cured product of this application is obtained by photocuring a coating film as follows: a coating film obtained by coating an alkaline developable resin composition onto copper and drying it; or a coating film obtained by coating the alkaline developable resin composition onto a carrier film and drying it, and then laminating the resulting photocurable dry film onto copper.

[0129] To create a cured product on a substrate with copper circuitry using a photocurable dry film, the cover film is peeled off, the resin layer is overlapped with the substrate with copper circuitry, and then laminated using a laminator or similar method to form a resin layer on the substrate with copper circuitry. The formed resin layer is then exposed, developed, and heat-cured in the same manner as described above to form a cured product. The carrier film can be peeled off before or after exposure.

[0130] Alkaline developable resin compositions are suitable for forming a curable coating on printed circuit boards. The curable coating is preferably a permanent insulating coating, and particularly preferably a solder resist layer.

[0131] Example

[0132] The present invention will be described in more detail based on the embodiments and comparative examples, but the scope of protection of the present invention and its implementation are not limited thereto. Unless otherwise specified, "parts" or "%" in the embodiments and comparative examples are based on weight. The morphology tests of the compositions of this embodiment were conducted using the methods described below.

[0133] Synthesis example

[0134] 214 parts of EPICLON N-695 cresol phenolic varnish-type epoxy resin (manufactured by DIC, epoxy equivalent = 214) were added to a four-necked flask equipped with a stirrer and a reflux condenser. 103 parts of carbitol acetate and 103 parts of petroleum-based hydrocarbon solvent (manufactured by Japan Energy Corporation, trade name: Cactus Fines SF-01) were added and heated to dissolve. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. The mixture was heated to 95–105°C, and 72 parts of acrylic acid were slowly added dropwise, allowing the reaction to proceed for 16 hours. The resulting reaction product was cooled to 80–90°C, and 91.2 parts of tetrahydrophthalic anhydride were added, allowing the reaction to proceed for 8 hours. After cooling, the product was removed. The resulting carboxyl vinyl ester resin had a non-volatile content of 65% and an acid value of 87.5 mg KOH / g for its solids.

[0135] Using the vinyl ester resin solution (varnish) of the synthetic example described above, the components and proportions (parts by weight) shown in Table 2 were mixed, premixed with a mixer, and then kneaded using a 3-roll mill to prepare an alkaline developing resin composition. Adhesion and resistance to thermal shock were evaluated according to the methods described below.

[0136] Table 2

[0137]

[0138] "-" indicates that no addition was made.

[0139] A synthetic example of a carboxyl vinyl ester resin has a solid content of 65%, which is equivalent to the carboxyl vinyl ester resin of (5).

[0140] Pigment F: Phthalocyanine Green, manufactured by Dai Nippon Ink & Chemical Co., Ltd. Defoamer AF: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd.

[0141] F. Dispersant: BYK-110, polyphosphate ester, manufactured by BYK Chemical Company. B. Photopolymerization initiator: Omnirad 369E (chemical name: 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone), manufactured by IGM Corporation.

[0142] C-type soft composite glass powder: K10, manufactured by Suzhou Jinyi New Material Technology Co., Ltd. (SiO2: 62.3-62.8%, Fe2O3: 0.0149-0.017%, Al2O3: 16.9-17.6%, CaO: 7.35-7.66%, MgO: 1.4-1.54%, B2O3: 9.6-10.3%), Mohs hardness: 5-6

[0143] E-Talc: LMP-100, manufactured by FUJI TALC INDUSTRIAL.

[0144] Silica: Manufactured by A-8 Sibelco

[0145] Solvent H: PGMEA, propylene glycol monomethyl ether acetate

[0146] G epoxy resin: N-770-75EA, manufactured by DIC, a phenolic varnish-type multifunctional epoxy resin, 75% solids.

[0147] Compounds with two or more vinyl unsaturated groups in molecule D: MT-3501G, manufactured by Zhangjiagang Dongya Di'ai Chemical Co., Ltd.

[0148] Performance evaluation:

[0149] (1) Adhesion (Pull-off test)

[0150] The alkaline developing resin compositions of the examples and comparative examples were screen-printed onto a substrate with a 2 mm copper wire pattern to a thickness of 40 μm. The substrate was then dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, an exposure apparatus equipped with a high-pressure mercury lamp was used at 300 mJ / cm². 2 The pattern was exposed, then developed in a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulating drying oven at 150°C for 60 minutes. This produced a copper circuit board with a cured film.

[0151] In addition, a DeFelsko PosiTest AT digital pull-out adhesion tester (capable of measuring the adhesion of coatings on metals, concrete, and other materials) was prepared. Using Emerson Cummins adhesive (LOCTITE ABLESTIK 2332-17 high-strength structural adhesive), the spindle (1cm in bottom diameter) was attached (e.g., [example missing]). Figure 3 (As shown in the schematic diagram) The curing film was adhered and fixed (heated at 120°C for 1 hour) to the surface of the above-mentioned curing film, and the pull force required to separate the curing film per unit area from the copper substrate was measured, expressed in MPa, according to ATSMD4541.

[0152] ○: Tensile strength above 6.0MPa

[0153] ×: Tensile strength less than 6.0 MPa

[0154] (2) Resistance to thermal shock

[0155] The alkaline developable resin compositions of the examples and comparative examples were screen-printed onto a substrate with a 2 mm copper wire pattern to a thickness of 40 μm. The substrate was then dried in a hot air circulating dryer at 80°C for 30 minutes. After cooling to room temperature, the pattern was exposed using an exposure apparatus equipped with a high-pressure mercury lamp at 400 mJ / cm². Following this, development was performed for 60 seconds in a 1 wt% sodium carbonate aqueous solution at 0.2 MPa pressure and 30°C, followed by curing in a hot air circulating dryer at 150°C for 60 minutes. A thermal shock resistance evaluation substrate with 17 right-angled resist patterns was fabricated by irradiating the substrate with ultraviolet light at a cumulative exposure of 2000 mJ / cm² in a UV transport oven. Multiple evaluation substrates prepared as described above were placed in a thermal shock cycler that cyclically rotated between -40°C and 160°C for different number of cycles to conduct thermal shock resistance tests (TCT tests). Then, observe the appearance at each cycle number and record the maximum number of cycles without cracking (for information on the presence or absence of cracks, please refer to...). Figure 1 and Figure 2 The evaluation criteria are as follows.

[0156] ○: No cracks after more than 1000 cycles

[0157] △: No cracks after 700 to less than 1000 cycles.

[0158] ×: Cracks appear when the number of cycles is below 700.

[0159] As can be seen from the above, by adjusting the composition to that of Examples 1-3, an alkaline developable resin composition that yields a solder resist layer with excellent resistance to thermal shock and excellent adhesion can be obtained. In contrast, in Comparative Examples 1 and 2, since only talc and silica were used as fillers, the adhesion was low. In Comparative Example 2, which used even less talc, the resistance to thermal shock was also reduced. Comparative Example 3 used only soft composite glass powder, which improved adhesion but resulted in low resistance to thermal shock. Comparative Example 4 used only silica, which similarly improved adhesion but resulted in low resistance to thermal shock. Comparative Example 5 used both soft composite glass powder and silica, which similarly improved adhesion but resulted in low resistance to thermal shock.

Claims

1. An alkaline developing resin composition, characterized in that, The product contains (A) vinyl ester resin, (B) photopolymerization initiator, (C) glass powder, (D) a compound having two or more vinyl unsaturated groups in one molecule, and (E) an inorganic filler, wherein the (E) inorganic filler comprises talc. Calculated by weight percent, the (C) glass powder contains SiO2: 60-65%, Fe2O3: 0.01-0.02%, Al2O3: 14-20%, CaO: 6-9%, MgO: 1-2%, B2O3: 8-12%, and the Mohs hardness of the (C) glass powder is less than 6.

5. The alkaline developing resin composition contains (G) epoxy resin, and the content of (G) epoxy resin is 10 to 100 parts by weight relative to 100 parts by weight of (A) vinyl ester resin based on solids.

2. The alkaline developing resin composition according to claim 1, characterized in that, It also contains (F) other additives besides (B) photopolymerization initiator and (C) glass powder.

3. The alkaline developing resin composition according to claim 1 or 2, characterized in that, It also contains (H) organic solvents.

4. A photocurable dry film, characterized in that, It is obtained by coating the alkaline developing resin composition according to any one of claims 1 to 3 onto a carrier film and drying it.

5. A cured product, characterized in that, It is obtained by photocuring the following coating: coating obtained by applying the alkaline developing resin composition according to any one of claims 1 to 3 onto copper and drying it; or coating the alkaline developing resin composition onto a carrier film and drying it, and then laminating the resulting photocurable dry film onto copper.

6. A printed circuit board, characterized in that, It comprises a cured product obtained by photocuring and then thermally curing a coating film, wherein the coating film is: a coating film obtained by coating an alkaline developable resin composition according to any one of claims 1 to 3 onto a substrate having copper circuits and drying it; or a coating film obtained by coating the alkaline developable resin composition onto a carrier film and drying it, and then laminating the resulting photocurable dry film onto a substrate having copper circuits.

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