Photosensitive resin composition, dry film, cured product, and electronic component

Abstract

The present invention provides a photosensitive resin composition having an excellent dry-to-touch property and an excellent drying management range, from which composition a cured product having excellent heat resistance, good thermal-shock resistance (flexibility), good external-impact resistance, a high reflectivity, and excellent discoloration resistance can be obtained, and a dry film, a cured product, and an electronic component obtained from the composition. The photosensitive resin composition is composed of a resin composition of at least a bi-component system, and comprises (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator, (E) an antioxidant, and (F) an epoxy resin. Relative to 100 parts by mass of the (A) carboxyl-containing resin on a solid basis, the amount of the (B) difunctional polyether polyurethane acrylate is greater than 1.2 parts by mass and less than 11 parts by mass.

Description

Photosensitive resin compositions, dry films, cured products, and electronic components Technical Field

[0001] The present invention relates to a photosensitive resin composition, a dry film having a resin layer comprising the photosensitive resin composition, a cured product having the resin layer of the dry film, and an electronic component having the cured product. Background Technology

[0002] Previously, the mainstream method of exposure, where a photomask is brought into contact with a photosensitive resin composition to form a specified pattern for solder resist, without air trapping, was the conventional method. However, in recent years, with the increasing density of printed circuit boards, direct image (DI) exposure, which does not use a photomask, is becoming more common due to the need for superior alignment accuracy. Direct image exposure (sometimes simply called DI exposure) is an exposure method that exposes the photosensitive resin composition while simultaneously scanning it using an LED light source, laser light source, or similar source. In this method, the white photosensitive resin composition (white solder resist ink) not only forms a solder resist that reflects LED light but also enables the miniaturization and narrowing of the mounting area for LED components.

[0003] While traditionally produced white photosensitive resin compositions have good heat resistance, they have poor resistance to yellowing. This means that with long-term use or in high-temperature environments, the light and heat from LED irradiation will accelerate the yellowing of the solder mask layer, resulting in a decrease in reflectivity and a reduction in light source utilization.

[0004] Patent Document 1 provides a white solder resist ink for LEDs, which discloses the use of a carboxyl-containing photosensitive resin without benzene ring structure, a composition of a compound containing two or more olefinic unsaturated groups in the molecule without benzene ring structure, a sulfur-free photoinitiator composition, and titanium dioxide, etc., to form a coating film with high whiteness and high reflectivity, while maintaining resistance to yellowing under high temperature of 200°C for 30 minutes and soldering conditions of 288°C for 30 seconds, thereby meeting the requirements of printed circuit boards for LEDs.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: CN104559456A Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, due to factors such as thermal expansion and contraction, if the solder resist ink has poor resistance to thermal shock, high-temperature storage performance, or reliability in response to changes in ambient temperature, problems such as shrinkage and cracking may occur, affecting the service life of electronic components. While the white solder resist ink for LEDs disclosed in Patent Document 1 focuses on the ink's reflectivity and resistance to yellowing, it does not address issues such as resistance to thermal shock and resistance to external impacts.

[0010] Solution for solving the problem

[0011] The purpose of this invention is to provide a photosensitive resin composition that can produce cured products with excellent heat resistance, good resistance to thermal shock (flexibility) and external impact resistance, high reflectivity and excellent colorfastness, and has excellent touch drying properties and drying range.

[0012] In addition, the present invention aims to provide a dry film having a resin layer comprising the above-described photosensitive resin composition, a cured product thereof, and an electronic component having the cured product.

[0013] The inventors conducted in-depth research and found that all the above-mentioned technical problems can be solved by providing the following photosensitive resin composition, thereby completing the present invention.

[0014] [1] This invention provides a photosensitive resin composition comprising at least a two-component resin composition, wherein the photosensitive resin composition contains: (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator, (E) an antioxidant, and (F) an epoxy resin.

[0015] The carboxyl-containing resin (A) and the difunctional polyether polyurethane acrylate (B) are contained in the first component, and the epoxy resin (F) is contained in a second component that is different from the first component.

[0016] Relative to 100 parts by weight of the carboxyl-containing resin (A) based on solid content, the difunctional polyether polyurethane acrylate (B) is 1.2 to 11 parts by weight.

[0017] [2]. The photosensitive resin composition according to [1], wherein at least the second component contains the (C) photosensitive monomer.

[0018] [3]. The photosensitive resin composition according to [1] or [2], wherein the (F) epoxy resin comprises bisphenol A phenolic varnish type epoxy resin.

[0019] [4]. The photosensitive resin composition according to [1] or [2], wherein the molar ratio of the epoxy group in the second component to the carboxyl group in the first component is 0.8 to 2.8.

[0020] [5]. The photosensitive resin composition according to [1] or [2], wherein the first component comprises at least one selected from the (C) photosensitive monomer, the (D) photopolymerization initiator and the (E) antioxidant.

[0021] [6]. The photosensitive resin composition according to [5], wherein the first component comprises the (C) photosensitive monomer, the (D) photopolymerization initiator and the (E) antioxidant.

[0022] [7]. The photosensitive resin composition according to [1] or [2], wherein the antioxidant (E) is 3.0 to 9.1 parts by weight relative to 100 parts by weight of the carboxyl-containing resin (A) based on solid content.

[0023] [8]. The present invention also provides a dry film having a resin layer comprising any one of the photosensitive resin compositions described in [1] to [7].

[0024] [9]. Furthermore, the present invention provides a cured product which is formed by curing the resin layer of the photosensitive resin composition described in any one of [1] to [7] or the dry film described in [8].

[0025]

[0010] . The present invention also provides an electronic component having the cured material described in [9].

[0026] The effects of the invention

[0027] According to the present invention, a photosensitive resin composition having excellent touch-drying properties and drying control range can be provided, and the cured product obtained therefrom also has excellent heat resistance, good resistance to thermal shock and external impact, high reflectivity and excellent colorfastness.

[0028] Furthermore, according to the present invention, a dry film having a resin layer comprising the above-described photosensitive resin composition, a cured product having the above-described properties, and an electronic component having the cured product may also be provided. Attached Figure Description

[0029] Figure 1 shows the evaluation results of resistance to external impact. In Figure 1A, the circuit board formed with conventional white ink is shown after punching, and in Figure 1B, the circuit board formed with the ink of the present invention is shown after punching. Detailed Implementation

[0030] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0031] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0032] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0033] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0034] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0035] In this specification, (meth)acrylic acid refers to the term collectively known as acrylic acid, methacrylic acid, and mixtures thereof, as well as other similar expressions.

[0036] The photosensitive resin composition of the present invention preferably comprises a resin composition of at least a two-component system. For example, a two-component system may be described where one resin composition serves as the main component (hereinafter referred to as the first component) and another resin composition serves as the curing agent component (hereinafter referred to as the second component). In this case, for example, the first component may contain at least (A) a carboxyl-containing resin and (B) a difunctional polyether-type polyurethane acrylate; and the second component may contain at least (C) a photosensitive monomer and (F) an epoxy resin.

[0037] Here, from the viewpoint of preventing chemical reactions during storage, the first component preferably comprises (A) a carboxyl-containing resin and (B) a difunctional polyether polyurethane acrylate, and at least one selected from (C) a photosensitive monomer, (D) a photopolymerization initiator and (E) an antioxidant; more preferably, it comprises (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator and (E) an antioxidant; even more preferably, it comprises (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator, (E) an antioxidant and (G) an inorganic filler; most preferably, it comprises (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator, (E) an antioxidant, (G) an inorganic filler and (H) other components.

[0038] Furthermore, if the epoxy resin (F) is in the same component as the aforementioned carboxyl-containing resin (A) and difunctional polyether polyurethane acrylate (B), the detailed mechanism is unclear. However, sometimes the flexibility of the photosensitive resin composition may be reduced or its developability and storage stability may be affected due to reactions between the components. The inventors of this invention have discovered that by using a first component containing at least (A) a carboxyl-containing resin and a specific amount of (B) a difunctional polyether polyurethane acrylate, and a second component containing at least (C) a photosensitive monomer and (F) an epoxy resin, the above-mentioned problems can be improved.

[0039] The components constituting the photosensitive resin composition of the present invention will be described below.

[0040] (A) Carboxyl-containing resin

[0041] Carboxyl-containing resins can become alkaline-developable by including carboxyl groups, and are preferably included in the first component described above. As (A) the carboxyl-containing resin, various conventionally known carboxyl-containing resins having carboxyl groups within the molecule can be used. Furthermore, from the perspective of curability and developability, in addition to carboxyl groups, it is preferable to use carboxyl-containing resins having olefinic unsaturated groups within the molecule.

[0042] As a specific example of (A) carboxyl-containing resins, the following compounds (both oligomers and polymers) can be listed.

[0043] (1) A carboxyl-containing resin obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with compounds containing unsaturated groups such as styrene, α-methylstyrene, lower alkyl esters of (meth)acrylic acid, and isobutylene.

[0044] (2) A carboxyl-containing polyurethane resin obtained by the addition polymerization reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-containing diol compounds such as dimethylolpropionic acid and dimethylolbutyric acid, as well as diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A epoxy alkyl adduct diols, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups.

[0045] (3) Polyurethane resin is obtained by addition polymerization of diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate with diol compounds such as polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A epoxy alkyl adduct diol, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups. The polyurethane resin is then reacted with acid anhydride to obtain a polyurethane resin with carboxyl groups at the end.

[0046] (4) A photosensitive carboxyl-containing polyurethane resin obtained by addition polymerization of diisocyanate with bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin, etc., meth)acrylate or its partial anhydride modified form, carboxyl-containing diol compound, and diol compound.

[0047] (5) A carboxyl-containing polyurethane resin obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups, such as (meth)acrylic acid hydroxyalkyl ester, to the resin synthesis of (2) or (4) above for terminal (meth)acrylation.

[0048] (6) A carboxyl-containing polyurethane resin is obtained by adding equimolar reactants of isophorone diisocyanate and pentaerythritol triacrylate to the resin synthesis of (2) or (4) above and performing terminal (meth)acrylation of compounds having one isocyanate group and one or more (meth)acryloyl groups.

[0049] (7) A photosensitive carboxyl-containing resin is obtained by reacting a multifunctional epoxy resin with (meth)acrylic acid to add phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and other dicarboxylic anhydrides to the hydroxyl groups present in the side chain.

[0050] (8) The multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the difunctional epoxy resin with epichlorohydrin is reacted with (meth)acrylic acid, and the generated hydroxyl groups are added to the dicarboxylic acid anhydride to obtain a carboxyl-containing resin.

[0051] (9) A carboxyl-containing polyester resin is obtained by reacting a polyfunctional oxoheterobutane resin with a dicarboxylic acid and adding the generated primary hydroxyl group to a dicarboxylic acid anhydride.

[0052] (10) A carboxyl-containing photosensitive resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with ethylene oxide, propylene oxide and other epoxides, reacting the reaction product with a monocarboxylic acid containing unsaturated groups, and reacting the reaction product with a polyacid anhydride.

[0053] (11) A carboxyl-containing photosensitive resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with cyclic carbonates such as ethylene carbonate and propylene carbonate, reacting the reaction product with a monocarboxylic acid containing unsaturated groups, and reacting the resulting reaction product with a polyacid anhydride.

[0054] (12) A carboxyl-containing photosensitive resin is obtained by reacting an epoxy resin having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenylethanol, with a monocarboxylic acid containing unsaturated groups, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with polyacid anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic anhydride.

[0055] (13) A carboxyl-containing resin having at least one of an amide structure and an imide structure.

[0056] (14) A photosensitive carboxyl-containing resin obtained by further adding (meth)acrylate, α-methylglycidyl (meth)acrylate, methyl 3,4-epoxycyclohexyl methacrylate, etc., to any of the carboxyl-containing resins mentioned in (1) to (13) above.

[0057] The carboxyl-containing resin (A) described above has a large number of free carboxyl groups in the side chains of the main polymer chain, and can therefore be developed by dilute alkaline aqueous solution. Preferably, it includes at least one of the carboxyl-containing resins described in (1), (7), (8), (10), (11), and (14) above.

[0058] (A) Carboxyl-containing resins can be used alone or in combination of two or more.

[0059] (A) The acid value of the carboxyl-containing resin is preferably in the range of 20 mg KOH / g or more and 140 mg KOH / g or less, more preferably in the range of 30 mg KOH / g or more and 120 mg KOH / g or less. (A) By making the acid value of the carboxyl-containing resin within the above range, alkaline development can be performed well, and a normal pattern of cured material can be formed.

[0060] (A) Carboxyl-containing resins can be any resin containing carboxyl groups in its molecule; there are no particular limitations on the resin skeleton. However, from the viewpoint of further improving insulation reliability and reflectivity, resins without a phenolic skeleton are preferred. When a carboxyl-containing resin does not contain a phenolic skeleton, it is less prone to discoloration due to thermal degradation, thus tending to have improved reflectivity. A phenolic skeleton refers to the skeleton of an aromatic compound having one or more hydroxyl groups directly bonded to an aromatic ring.

[0061] (A) The weight-average molecular weight of the carboxyl-containing resin varies depending on the resin skeleton, but is generally preferably 2,000 or more and 150,000 or less. When the weight-average molecular weight is 2,000 or more, the dried coating exhibits good non-stickiness (touch-drying), good moisture resistance after exposure, and good resolution, and there is no film reduction during development. On the other hand, when the weight-average molecular weight is 150,000 or less, the developability and storage stability are good. More preferably, it is 5,000 or more and 100,000 or less.

[0062] Based on solids content, the amount of carboxyl-containing resin (A) in the formulation is preferably 10% by mass or more and 70% by mass or less relative to the photosensitive resin composition, more preferably 15% by mass or more and 65% by mass or less, and particularly preferably 19% by mass or more and 60% by mass or less. When it is 10% by mass or more, the decrease in the strength of the cured film can be suppressed. On the other hand, when it is 70% by mass or less, the viscosity of the photosensitive resin composition does not become too high, and the coatability is good.

[0063] Furthermore, the aforementioned (A) carboxyl-containing resin is not limited to the substances listed above. In addition, it can be used alone or in combination of two or more. From the viewpoint of better realizing the technical effect of this application, it is preferable to use two or more (A) carboxyl-containing resins in combination. Commercially available (A) carboxyl-containing resins that can be used in combination include CYCLOMER P(ACA)Z250 (manufactured by Daicel Chemical Industry Co., Ltd.) and UE-6500 (manufactured by DIC Corporation).

[0064] (B) Difunctional polyether polyurethane acrylate

[0065] Through research, the inventors discovered that adding (B) difunctional polyether polyurethane acrylate to the first component enables the formed cured product to possess excellent heat resistance, good resistance to thermal shock (flexibility), resistance to external impact, high reflectivity, and excellent colorfastness. While the detailed mechanism is not fully understood, it is speculated that difunctional polyether polyurethane acrylates have multiple polymerizable forms, excellent mechanical properties, and a suitable number of double bonds. Therefore, containing a specific amount of (B) difunctional polyether polyurethane acrylate in the first component ensures both a certain degree of toughness and colorfastness of the photosensitive resin composition. In contrast, trifunctional and higher functionalities, due to their better rigidity, are more brittle, and the resulting cured product cannot guarantee excellent heat resistance, high reflectivity, good resistance to thermal shock (flexibility), and resistance to external impact.

[0066] As for (B) difunctional polyether polyurethane acrylate, it is preferable to use a polyether whose ends are capped with polyurethane acrylate. Commercially available (B) difunctional polyether polyurethane acrylate products include KAYARAD UX-2201W (manufactured by Wuxi Chemical Chemical Co., Ltd.), KAYARAD UXF-4001-M35, and KAYARAD UXF-4002 (all manufactured by Nippon Kayaku Co., Ltd.).

[0067] As the amount of (B) difunctional polyether polyurethane acrylate in the formulation, relative to 100 parts by weight of the (A) carboxyl-containing resin based on solid content, the amount of (B) difunctional polyether polyurethane acrylate is 1.2 to 11 parts by weight, preferably 2.5 to 10 parts by weight, more preferably 3.5 to 8.0 parts by weight, and most preferably 4.5 to 6.9 parts by weight.

[0068] (C) Photosensitive monomer

[0069] The photosensitive resin composition capable of forming the cured product of the present invention may contain commonly known photosensitive monomers. The photosensitive monomer (C) is preferably contained in at least the second component described above, and more preferably in both the first and second components described above.

[0070] The (C) photosensitive monomer can be, for example, a compound having one or more olefinic unsaturated groups in its molecule. This (C) photosensitive monomer facilitates (in the case of containing olefinic unsaturated groups) photocuring of the (A) carboxyl-containing resin based on active energy ray irradiation, thereby curing the photosensitive resin composition.

[0071] The photosensitive monomers preferably used in this invention include, for example, methyl α-(allyloxymethyl)acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, and other diol diacrylates, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, etc. Propylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, diacrylates of diols obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diacrylates of caprolactone-modified hydroxypentanoic acid neopentyl glycol diacrylate, diacrylates of bisphenol A EO adduct, diacrylates of bisphenol A PO adduct, tricyclodecanediethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate Diacrylates with cyclic structures, or difunctional (meth)acrylates such as their corresponding methacrylate monomers, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphate triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxy pentaacrylate, or polyfunctional acrylates represented by their sesquioxane-modified derivatives, or polyfunctional (meth)acrylates such as their corresponding methacrylate monomers, trifunctional methacrylates, ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof.

[0072] In the first component described above, the content of this (C) photosensitive monomer is preferably in the range of 2 to 20.0 parts by weight, more preferably in the range of 4.0 to 15.0 parts by weight, relative to 100 parts by weight of the (A) carboxyl-containing resin based on solids. If the content of the (C) photosensitive monomer is within the above range, the photosensitive resin composition has sufficient photocurability, patterning during development becomes better, and touch drying properties also become better.

[0073] In the second component described above, the content of this (C) photosensitive monomer is preferably in the range of 5.0 to 35.0 parts by weight, more preferably in the range of 10.0 to 35.0 parts by weight, relative to 100 parts by weight of the (A) carboxyl-containing resin based on solid content. If the content of the (C) photosensitive monomer is within the above range, the photosensitive resin composition has sufficient photocurability, patterning during development becomes better, and touch drying properties also become better.

[0074] (D) Photopolymerization initiator

[0075] As for the (D) photopolymerization initiator used in the photosensitive resin composition of the present invention, there are no particular limitations as long as it is a photopolymerization initiator commonly used in photosensitive resin compositions, and the (D) photopolymerization initiator is preferably included in the first component described above.

[0076] As photopolymerization initiators (D), known substances can be used, including: benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoin and its alkyl ether series; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4-(1-tert-butyldioxy-1-methylethyl)acetophenone, and other acetophenone series; 2-methylanthraquinone, 2-pentylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and other anthraquinone series; isopropylthiophene Thioxanone series such as oxanone, 2,4-dimethylthioxanone, 2,4-diisopropylthioxanone, and 2-chlorothioxanone; ketal series such as acetophenone dimethyl ketal and benzoyl dimethyl ketal; benzophenone series such as 4,4'-bis(diethylamino)benzophenone, 4-(1-tert-butyldioxy-1-methylethyl)benzophenone, and 3,3',4,4'-tetra(tert-butyldioxycarbonyl)benzophenone; and oxanthone series, etc.

[0077] Alternatively, as a photopolymerization initiator, one or more photopolymerization initiators selected from the group consisting of oxime ester-based photopolymerization initiators having an oxime ester group, alkyl phenyl ketone-based photopolymerization initiators, α-aminoacetophenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and diacene-based photopolymerization initiators may be used.

[0078] Examples of α-aminoacetophenone-based photopolymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone. Commercially available products include Omnirad 907, Omnirad 369, and Omnirad 379 manufactured by IGMresins B.V.

[0079] 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 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO; (Di-p-tolylphosphoryl)(mesityl)methanone). Commercially available products include Omnirad TPO manufactured by IGMresins, Omnirad 819 manufactured by IGMresins B.V., Ltcure TMO manufactured by PhiChem, and GR-TPO manufactured by Hubei Gurun Technology Co., Ltd.

[0080] 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 IGMresins B.V.

[0081] As photopolymerization initiators, thioxanthone-based and benzophenone-based photopolymerization initiators are preferred. Isopropyl thioxanthone-based and 4,4'-bis(diethylamino)benzophenone are more preferred. Using thioxanthone-based and acylphosphine oxide-based photopolymerization initiators can yield cured patterns with excellent deep curing properties and suppressed undercutting. Commercially available products include ITX manufactured by DKSH JAPAN and EAB manufactured by Daido Chemical Industries, Ltd.

[0082] The amount of photopolymerization initiator (D) is preferably 3.0 to 20 parts by weight, more preferably 4.0 to 18 parts by weight, further preferably 5.0 to 15 parts by weight, and particularly preferably 6.0 to 13 parts by weight, relative to 100 parts by weight of the carboxyl-containing resin (A) based on solid content. By blending the photopolymerization initiator within the above range, a photosensitive resin composition with excellent photocurability and developability, as well as improved adhesion, can be obtained.

[0083] (E) Antioxidants

[0084] The photosensitive resin composition of the present invention may contain antioxidants such as free radical scavengers that neutralize generated free radicals and peroxide decomposers that decompose generated peroxides into harmless substances and prevent the generation of new free radicals. The antioxidants used in the present invention can prevent oxidative degradation of resins, etc., further inhibit yellowing, and improve colorfastness. (E) The antioxidant is preferably included in the first component described above. (E) The antioxidant may be used alone or in combination of two or more.

[0085] As the (E) antioxidant used in the photosensitive resin composition of the present invention, from the perspective of further benefiting the realization of the object of the present invention, an antioxidant that functions as a free radical scavenger is preferred, and a hindered phenolic antioxidant is more preferred.

[0086] Examples of antioxidants that function as free radical scavengers include: hydroquinone, 4-tert-butylcatechol, 2-tert-butylhydroquinone, hydroquinone monomethyl ether, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, 2,2-methylene-bis(4-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl- Phenolic compounds such as 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 1,3,5-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)-triazine-2,4,6-(1H,3H,5H)trione; quinone compounds such as p-methoxyphenol and benzoquinone; amine compounds such as bis(2,2,6,6-tetramethyl-4-piperidinyl)-sebate and phenothiazine. Commercially available products include, for example, ADEKASTAB. AO-30, ADEKASTAB AO-330, ADEKASTAB AO-20, ADEKASTAB LA-77, ADEKASTAB LA-57, ADEKASTAB LA-67, ADEKASTAB LA-68, ADEKASTAB LA-87 (above, made by ADEKA CORPORATION), IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX 1135, TINUVIN 111FDL, TINUVIN 123, TINUVIN 144, TINUVIN 152, TINUVIN 292, TINUVIN 5100 (above, made by BASF JAPAN LTD., trade name), CHINOX Examples of hindered phenolic antioxidants include TP-10H (manufactured by Double Bond Chemical Co., Ltd.); examples of hindered phenolic antioxidants include 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxellaspiro[5.5]undecane and pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). Commercially available products meeting the above criteria include, for example, MIANOX AO-80 (manufactured by Nanjing Milan Chemical Co., Ltd.) and IRGANOX 1010 (manufactured by BASF).

[0087] Antioxidants that function as peroxide decomposers include, for example, phosphorus compounds such as triphenyl phosphite, and sulfur compounds such as pentaerythritol tetra(lauryl thiopropionate), dilauryl thiodipropionate, and dioctadecyl 3,3'-thiodipropionate. Commercially available examples include ADEKASTAB TPP (manufactured by ADEKA CORPORATION), MARK AO-412S (manufactured by ADEKA CORPORATION), and Sumilizer TPS (manufactured by Sumitomo Chemical Co., Ltd.).

[0088] The proportion of the antioxidant (E) is suitable as 3.0 to 9.1 parts by weight relative to 100 parts by weight of the carboxyl-containing resin (A) in solids, preferably 3.4 to 9.1 parts by weight, more preferably 3.4 to 7.1 parts by weight, even more preferably 3.4 to 5.2 parts by weight, and particularly preferably 3.4 to 4.6 parts by weight. Using an amount of antioxidant (E) within the above range ensures excellent touch-drying properties and drying range of the photosensitive resin composition without affecting printability, and maintains the heat resistance, thermal shock resistance, and impact resistance of the cured product obtained therefrom.

[0089] (F) Epoxy resin

[0090] The (F) epoxy resin used in the photosensitive resin composition of the present invention is a component used to impart heat resistance, and is preferably included together with the aforementioned (C) photosensitive monomer in a second component different from the first component. Only one type of (F) epoxy resin may be used, or two or more types may be used in combination. Furthermore, from the viewpoint of further improving heat resistance, the epoxy resin preferably comprises an epoxy resin having an aromatic backbone. Moreover, both liquid and solid epoxy resins can be used.

[0091] Examples of epoxy resins with an aromatic backbone include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol phenolic varnish type epoxy resin, phenol phenolic varnish type epoxy resin, glycidyl ester type epoxy resin obtained by reacting a polyacid compound with an aromatic backbone with epichlorohydrin, and glycidyl ether type epoxy resin with an aromatic backbone. From the viewpoint of further improving the strength, heat resistance, and colorfastness of the cured product, epoxy resins with an aromatic backbone are preferably epoxy resins with a bisphenol backbone or a phenolic varnish backbone, more preferably epoxy resins with both a bisphenol backbone and a phenolic varnish backbone, and most preferably bisphenol A phenolic varnish type epoxy resin.

[0092] The epoxy equivalent of the epoxy resin having the aromatic backbone described above is preferably 100 or more and 1000 or less. If the epoxy equivalent is 100 or more, the formability of the photosensitive resin composition will be better. If the epoxy equivalent is 1000 or less, the formability will be further improved.

[0093] Commercially available epoxy resins with the aforementioned aromatic backbone include, for example: PNE-177 (phenolic varnish type epoxy resin), CNE-200EL, 704P-CA75 (cresol phenolic varnish type epoxy resin), and BNE200D75 (bisphenol A phenolic varnish type epoxy resin) manufactured by Changchun Artificial Resin Factory (Co., Ltd.); NPEL-128E (bisphenol A type epoxy resin) manufactured by Nan Ya Plastics Co., Ltd.; and jER157S (bisphenol A phenolic varnish type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd. However, it is not limited to using the epoxy resins listed above. For example, it can use naphthyl-containing epoxy resins such as ESN-190 and ESN-360 manufactured by NIPPON STEEL Chemical & Material Co., Ltd., HP-4032, EXA-4750, and EXA-4700 manufactured by DIC Corporation, and epoxy resins with a dicyclopentadiene backbone such as HP-7200 and HP-7200H manufactured by DIC Corporation.

[0094] The amount of epoxy resin used in the formulation can be appropriately adjusted by applying heat and allowing for moderate curing, and there is no particular limitation. However, insufficient epoxy resin will result in insufficient strength of the cured film; excessive epoxy resin will affect the developing performance of the ink. The inventors have unexpectedly discovered that when the ratio of carboxyl groups to epoxy groups, by mass, is within the following specific range, excellent touch-drying properties and drying range of the photosensitive resin composition of the present invention can be guaranteed, and simultaneously a cured product with excellent heat resistance, good resistance to thermal shock (flexibility), resistance to external impact, high reflectivity, and excellent colorfastness can be obtained. The molar ratio of epoxy groups from the epoxy resin in the second component to carboxyl groups from the carboxyl-containing resin in the first component, i.e., epoxy groups in the second component / carboxyl groups in the first component, is preferably 0.8 to 2.8, more preferably 1.0 to 2.6, further preferably 1.4 to 2.4, and most preferably 1.8 to 2.2.

[0095] (G) Inorganic packing

[0096] The photosensitive resin composition of the present invention may further include (G) inorganic filler. One type of inorganic filler may be used alone, or two or more may be used in combination.

[0097] The amount of inorganic filler mixed with the material is preferably in the range of 200 to 260 parts by weight relative to 100 parts by weight of carboxyl-containing resin (A) based on solid content, more preferably in the range of 210 to 250 parts by weight, and even more preferably in the range of 220 to 240 parts by weight. When the amount of inorganic filler mixed with the material is 200 parts by weight or more, there is a tendency to obtain a cured film with better solder heat resistance, reflectivity, and colorfastness. When the amount of inorganic filler (especially titanium dioxide) mixed with the material is too low, there is a tendency to not be able to obtain sufficient reflectivity. When the amount of inorganic filler mixed with the material is too high, there is a tendency to deteriorate the developability of the ink and the resistance to thermal shock.

[0098] Examples of inorganic fillers include titanium dioxide, silicon dioxide, barium sulfate, barium titanate, Neuburg silica, talc, clay, titanium dioxide, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, the inclusion of at least one of talc, silicon dioxide, and titanium dioxide is preferred, as it can inhibit the curing shrinkage of the cured photosensitive resin composition and improve properties such as adhesion, hardness, and reflectivity.

[0099] From the perspective of improving the mechanical properties, heat resistance, resistance to external impact and resistance to thermal shock of the cured product, inorganic fillers are preferably included in the first component.

[0100] Inorganic fillers can be surface-treated, and more preferably, their surfaces are surface-treated to introduce curable reactive groups.

[0101] Here, curable reactive groups refer to groups that undergo a curing reaction with epoxy resins and other carboxyl-containing resins. These can be photocurable or thermocurable reactive groups. Examples of photocurable reactive groups include methacryloyl, acryloyl, vinyl, and styrene groups. Examples of thermocurable reactive groups include epoxy, amino, hydroxyl, carboxyl, isocyanate, imino, oxetane, mercapto, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, and oxazoline groups.

[0102] There are no particular limitations on the method for introducing curable reactive groups onto the surface of inorganic fillers. Commonly known methods can be used. Surface treatment agents with curable reactive groups, such as coupling agents with curable reactive groups as organic groups, can be used to treat the surface of the inorganic fillers. As coupling agents, silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents can be used. It should be noted that examples of inorganic fillers that have undergone surface treatment without curable reactive groups include silica-alumina surface treatment, titanate-based coupling agent treatment, aluminate-based coupling agent treatment, and organically treated inorganic fillers.

[0103] The average particle size (D50) of the inorganic filler is 2000 nm or less, more preferably 1200 nm or less. In addition, the lower limit value, in terms of average particle size (D50), is preferably 0.1 nm or more.

[0104] The smaller the average particle size of inorganic fillers, the more diffuse reflection is suppressed during light irradiation, which facilitates the fine processing of cured patterns. The average particle size (D50) can be determined using a laser diffraction-based particle size distribution measuring device and a measuring device based on dynamic light scattering. For example, the Microtrac MT3300EXII manufactured by MicrotracBEL Inc. is a laser diffraction-based measuring device, and the Nanotrac Wave II UT151 manufactured by MicrotracBEL Inc. is a dynamic light scattering-based measuring device.

[0105] (H) Other components

[0106] In the photosensitive resin composition of the present invention, additives may be further mixed as other components (H) as needed without departing from the purpose of the present invention.

[0107] Examples of such components include thermosetting catalysts. Examples of thermosetting catalysts include imidazole derivatives such as imidazole, 2-methylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 4-phenylimidazolium, 1-cyanoethyl-2-phenylimidazolium, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazolium; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipate dihydrazide and sebacic dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, commercially available substances include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole derivatives) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT 3513N (a trade name of a dimethylamine compound), DBU, DBN, and U-CAT SA102 (all bicyclic amidine compounds and their salts) manufactured by San-Apro Co., Ltd. Not particularly limited to these, thermosetting catalysts for epoxy resins or oxazolidine compounds, or substances that promote the reaction of at least one epoxy group and an oxazolidine group with a carboxyl group, are also acceptable.

[0108] In addition, guanidine, acetylguanidine, phenylguanidine, melamine, and reactants of melamine with organic acids such as phthalic acid, namely melamine organic acid salts, 2,4-diamino-6-methacryloyloxyethyl-triazine, 2-vinyl-2,4-diamino-triazine, 2-vinyl-4,6-diamino-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-triazine isocyanuric acid adduct, and other triazine derivatives, are also used. These compounds can also function as adhesion promoters when combined with thermosetting catalysts.

[0109] Thermosetting catalysts can be used alone or in combination of two or more.

[0110] The amount of thermosetting catalyst mixed in is preferably 0.1 to 5% by mass relative to the total amount of the photosensitive resin composition in terms of solid content, more preferably 0.1 to 3% by mass.

[0111] Examples of such components include colorants such as pigments and dyes, heat-resistant polymerization inhibitors, thermosetting catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, volatility agents, antioxidants, antibacterial / mildew inhibitors, defoamers, leveling agents, rheology modifiers, anti-sagging agents, thickeners, adhesion promoters, thixotropic promoters, photoinitiators, sensitizers, photoalkalizing agents, thermoplastic resins, elastomers, organic fillers, mold release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, cellulose resins, etc. In the first and second components of the photosensitive resin composition of the present invention, the aforementioned other components may optionally be added to at least one of them. From the perspective of further achieving the above-mentioned effects, it is more preferable to add them to the first component. Among these, in addition to pigments and dyes, titanium dioxide and the like can also be used as colorants.

[0112] Melamine is preferably added. As an antioxidant, it improves the adhesion between the substrate and the cured film of the resin composition by inhibiting the oxidation of the conductor (copper) on the substrate. As a thermosetting catalyst, it promotes the reaction between epoxy groups and carboxyl groups. This improves the thermal shock resistance, impact resistance, and hardness of the dry film and cured product formed by the photosensitive resin composition. The amount of melamine added is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, further preferably 1.0 to 10 parts by weight, and particularly preferably 2.0 to 5.0 parts by weight, relative to 100 parts by weight of the carboxyl-containing resin (A) based on solids.

[0113] The first and second components of the photosensitive resin composition of the present invention can be prepared by mixing and dispersing these components in a predetermined amount, for example, using a three-roll mill.

[0114] solvent

[0115] In this invention, for general purposes, such as for preparing the various component systems of a photosensitive thermosetting resin composition and adjusting its viscosity, a solvent may be used in at least one component system.

[0116] The solvent can be a conventional organic solvent, such as: ketones like methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons like toluene, xylene, and tetramethylbenzene; glycol ethers like cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; polyol ethers; alkyl esters of organic acids like ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate (CA), butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; polyol esters; aliphatic hydrocarbons like octane and decane; and petroleum solvents like petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha.

[0117] These conventional organic solvents can be used alone or in combination of two or more.

[0118] Relative to 100 parts by weight of (A) carboxyl-containing resin (based on solids), the content of conventional solvent in the first component of the photosensitive resin composition of the present invention is preferably in the range of 100 to 130 parts by weight, more preferably in the range of 105 to 120 parts by weight. Furthermore, without affecting the technical effects of the present invention, the second component may optionally contain the aforementioned solvent. Relative to 100 parts by weight of (A) carboxyl-containing resin (based on solids), the content of conventional solvent in the second component of the photosensitive resin composition of the present invention is preferably in the range of 2.0 to 20 parts by weight, more preferably in the range of 2.0 to 18 parts by weight.

[0119] dry film

[0120] The photosensitive resin composition of the present invention can also be formed into a dry film, the dry film comprising: a support (carrier) film; and a resin layer formed on the support film by the above-described photosensitive resin composition. During dry film formation, the photosensitive resin composition of the present invention is diluted with the above-described organic solvent to an appropriate viscosity, and coated onto the support film with a uniform thickness using a corner roller coater, doctor blade coater, lip coater, bar coater, extrusion coater, reverse coater, transfer roller coater, gravure coater, spray coater, etc. The film is typically dried at a temperature of 50–130°C for 1–30 minutes to obtain the film. There are no particular limitations on the coating thickness; a range of 1–150 μm, preferably 10–60 μm, based on the dried film thickness, is generally suitable.

[0121] After forming the resin layer of the photosensitive resin composition of the present invention on the support film, a peelable protective (covering) film is preferably laminated on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. As the peelable protective film, for example, polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc., can be used, as long as the protective film has a lower adhesive force between the resin layer and the protective film than the adhesive force between the resin layer and the support film when the protective film is peeled off.

[0122] It should be noted that, in this invention, a resin layer can be formed by coating the photosensitive resin composition of this invention onto the aforementioned protective film and drying it, and then a support film can be laminated on its surface. That is, in this invention, when manufacturing the dry film, either a support film or a protective film can be used as the film onto which the photosensitive resin composition of this invention is coated.

[0123] Cured material

[0124] The cured product of the present invention is obtained by curing the resin layer of the photosensitive resin composition of the present invention or the dry film of the present invention. It has excellent heat resistance, good resistance to thermal shock (flexibility) and external impact resistance, high reflectivity and excellent colorfastness.

[0125] Printed Circuit Board

[0126] The printed circuit board of the present invention has a cured product obtained from the resin layer of the photosensitive resin composition or dry film of the present invention. As a method for manufacturing the printed circuit board of the present invention, for example, the photosensitive resin composition of the present invention is adjusted to a viscosity suitable for a coating method using the aforementioned organic solvent, and then coated onto a substrate using methods such as dip coating, flow coating, roller coating, bar coating, screen printing, or curtain coating. The organic solvent contained in the photosensitive resin composition is then evaporated and dried (temporary drying) at a temperature of 60–100°C, thereby forming a non-sticky resin layer on the surface of the substrate. Alternatively, in the case of a dry film, after adhering the resin layer to the surface of the substrate in contact with the substrate using a laminator or the like, the carrier film is peeled off, thereby forming a resin layer on the surface of the substrate.

[0127] As the aforementioned substrates, in addition to printed circuit boards and flexible printed circuit boards pre-formed with copper or the like, examples include: copper-clad laminates of all grades (FR-4, etc.) made of materials such as paper phenolic resin, paper epoxy resin, glass cloth epoxy resin, glass polyimide resin, glass cloth / non-woven epoxy resin, glass cloth / paper epoxy resin, synthetic fiber epoxy resin, fluororesin / polyethylene / polyphenylene ether resin, and polyphenylene oxide / cyanate ester resin for high-frequency circuits; as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafer boards.

[0128] The evaporative drying following coating of the photosensitive resin composition of the present invention can be carried out by means of a hot air circulating drying oven, IR oven, hot plate, convection oven, etc. (using a device equipped with a heat source that uses steam to heat the air, and a method of making hot air in the dryer convect and contacting the air, or by blowing it onto the support using a nozzle).

[0129] After forming a resin layer on the surface of the substrate, the substrate is selectively exposed using active energy rays. The unexposed areas are then developed using a dilute alkaline aqueous solution (e.g., 0.3–3% sodium carbonate aqueous solution) to form a pattern of the cured material. Subsequently, the cured material is irradiated with active energy rays and then heat-cured (e.g., at 100–220°C), or heat-cured and then irradiated with active energy rays, or finally fully cured by heat alone (formal curing), thereby forming a cured film with excellent adhesion, hardness, and other properties.

[0130] The exposure machine used for the aforementioned active energy ray irradiation can be any device that irradiates ultraviolet light, such as an LED light source lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, or a mercury short-arc lamp. Alternatively, a direct tracing device (e.g., a laser direct imaging device that uses CAD data from a computer to directly draw an image using laser light) can also be used. The exposure wavelength for the direct tracing machine is preferably in the range of 380–450 nm. The exposure amount used for image formation varies depending on the film thickness, and can typically be set to 10–1500 mJ / cm². 2 The optimal value can be set to 20–1000 mJ / cm². 2 Within the range.

[0131] As the above-mentioned developing method, immersion method, spraying method, spraying method, brushing method, etc. can be used. As the developing solution, alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc. can be used.

[0132] The photosensitive resin composition of the present invention is suitable for forming cured films on electronic components of electronic devices requiring miniaturization and high performance, and is particularly suitable for forming white solder resist layers on printed circuit boards with LEDs requiring miniaturization and high density. It should be noted that the photosensitive resin composition of the present invention can also be used to form interlayer insulating layers or capping layers.

[0133] The following examples and comparative examples illustrate the present invention in detail, but the present invention is not limited to the following examples. It should be noted that, unless otherwise specified, "parts" and "%" are all mass references.

[0134] Example

[0135] <Preparation of Photosensitive Resin Composition>

[0136] The components were mixed according to the formulations shown in Tables 1 and 2 below, stirred, and then mixed and dispersed using a three-roll mill to prepare the photosensitive resin compositions (two-component systems formed by the first component and the second component) of Examples 1 to 7 and Comparative Examples 1 to 8.

[0137] [Table 1]

[0138] [Table 2]

[0139] The components listed in Tables 1 and 2 are as follows.

[0140] *1: CYCLOMER P(ACA)Z250 (45% solids), manufactured by Daicel Chemical Industries, Ltd., corresponding to categories (1) and (14) in the description of carboxyl-containing resins in (A) above.

[0141] *2: UE-6500 (50% solids), manufactured by DIC Corporation, corresponding to categories (1) and (14) in the description of carboxyl-containing resins in (A) above.

[0142] *3: KAYARAD UX-2201W, difunctional polyether polyurethane acrylate, manufactured by Chemical Pharmaceutical (Wuxi) Co., Ltd.

[0143] *4: MT3501A, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, manufactured by Zhangjiagang Dongya Di'ai Chemical Co., Ltd.

[0144] *5: ITX, Isopropylthioxanthone, manufactured by DKSH JAPAN.

[0145] *6: #819, Omnirad 819, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, manufactured by IGMresins B.V.

[0146] *7: GR-TPO, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, manufactured by Hubei Gurun Technology Co., Ltd.

[0147] *8: IRGANOX 1010, hindered phenolic antioxidant, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), manufactured by BASF.

[0148] *9: L-300, hydrated amorphous silica, manufactured by Tosoh Silicon Chemical Co., Ltd.

[0149] *10: HD25, Talc, Manufactured by Fushi (Shanghai) Trading Co., Ltd.

[0150] *11: Tiona 696, titanium dioxide, inorganic filler / colorant, manufactured by Tronox Pigment Bunbury Ltd.

[0151] *12: ORBEN DPM-B, a volatility modifier, manufactured by White Stone Calcium (Shanghai) International Trading Co., Ltd.

[0152] *13: KS-66, defoamer, manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0153] *14: BYK-110, defoamer, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0154] *15: Melamine Funsan, manufactured by Kunshan Qiangwei Powder Equipment Co., Ltd.

[0155] *16: DS-100, defoamer, manufactured by Foshan Nanhai Datian Chemical Co., Ltd.

[0156] *17: Rheology additive, anti-sagging agent, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0157] *18: DPM, dipropylene glycol monoether, manufactured by Taiwan LyondellTech Co., Ltd.

[0158] *19: BNE200D75, Bisphenol A phenolic varnish-type epoxy resin (75% solids), manufactured by Changchun Artificial Resin Factory (stock).

[0159] *20: 704P-CA75, Cresol-phenolic varnish-type epoxy resin (75% solids), manufactured by Changchun Artificial Resin Factory (stock).

[0160] *21: APG-700, polypropylene glycol diacrylate, manufactured by Nantong Xinzhongcun Chemical Co., Ltd.

[0161] *22: EB9260, aliphatic polyurethane acrylate (3-functional), manufactured by Cytec Corporation.

[0162] The following tests were conducted on the photosensitive resin compositions of the obtained examples and comparative examples.

[0163] <Evaluation of substrate fabrication>

[0164] Prepare the experimental substrate according to the following steps.

[0165] Substrate: FR-4 experimental substrate was used;

[0166] Pretreatment: pickling → washing → non-woven fabric (Buff#600+#1000) grinding → washing → drying;

[0167] Printing: Manual screen printing (screen: 100 mesh);

[0168] Drying: Use a hot air circulating dryer to dry at 80℃ for 30 minutes;

[0169] Exposure: Exposure lamp halogen lamp 7kw ORC HMW-680GW;

[0170] Development: The pattern was obtained by developing a 1% sodium carbonate aqueous solution at 30°C for 90 seconds under a spray pressure of 0.2 MPa.

[0171] Curing: Use a hot air circulating dryer to cure at 150℃ for 60 minutes;

[0172] Ink film thickness: 20±2μm

[0173] <Reflectivity>

[0174] For the above-mentioned evaluation substrate, the reflectance of the cured material at 460 nm was measured using a KONICAMINOLTA spectrophotometer CM-26d, and the results are shown in Table 3 below.

[0175] <Colorfastness>

[0176] For the aforementioned evaluation substrate, the initial values ​​of L*, a*, and b* on the ink surface of the substrate were measured using a CM-2600D colorimeter (fixed area). Then, the substrate was placed in a 200℃ oven and baked for 1.0 hour. The values ​​of L*, a*, and b* in the same area were measured again using the CM-2600D colorimeter, and the color difference was calculated to obtain ΔE*ab. The results are shown in Table 3 below.

[0177] It should be noted that ΔE*ab is the difference between the initial value and the value after each treatment in the L*a*b* color system. The larger the value, the more obvious the color change and the worse the color resistance.

[0178] The formula for calculating ΔE*ab is as follows:

[0179] ΔE*ab=[(L *2 -L *1 ) 2 +(a *2 -a *1 ) 2 +(b *2 -b *1 ) 2 ] 1 / 2

[0180] In the formula, L *1 a *1 b *1 Let L*, a*, and b* represent the initial values ​​respectively. *2 a *2 b *2 These represent the values ​​of L*, a*, and b* after each processing step.

[0181] Solder heat resistance

[0182] The aforementioned evaluation substrates coated with rosin-based flux were immersed in a solder bath at 260°C for 30 seconds. After washing the flux with modified alcohol, a peel test was performed to evaluate the peeling of the resist layer. The evaluation criteria are as follows, and the evaluation results are shown in Table 3 below.

[0183] ○: No peeling can be seen.

[0184] △: There is some disconnection between the circuits.

[0185] ×: Unrelated to the circuit, completely disconnected.

[0186] <Touch dryness>

[0187] On a copper-clad laminate polished by a polishing roller, the photosensitive resin compositions of the above-mentioned examples and comparative examples are screen-printed onto the entire surface. The substrate is then dried at 80°C for 30 minutes. The touch dryness of the coating surface is evaluated based on the following criteria, and the evaluation results are shown in Table 3 below.

[0188] ○: Not sticky at all

[0189] △: Slightly sticky

[0190] ×: Sticky

[0191] <Drying Management Range>

[0192] The photosensitive resin compositions of the examples and comparative examples were screen-printed onto a patterned copper foil substrate. The substrates were dried in a hot air circulating drying oven at 75°C for 60 minutes, then removed and slowly cooled to room temperature. The substrates were developed using a 1 wt% sodium carbonate aqueous solution at 30°C under a spray pressure of 0.2 MPa for 60 seconds, and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 3 below.

[0193] ○: No residue was found

[0194] △: Slight residue appears

[0195] ×: A large amount of residue appeared.

[0196] <Resistance to thermal shock>

[0197] The photosensitive 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, and 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 400 mJ / cm². 2 Pattern exposure was performed, followed by development 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. The substrate was then cured in a hot air circulating drying oven at 150°C for 60 minutes to form an evaluation substrate. Multiple evaluation substrates prepared as described above were placed in a thermal cycling machine that cyclically rotated temperatures between -40°C and 125°C, and different number of cycles (25, 50, and 75 cycles) were set for thermal shock cycling (TCT) tests. The appearance was then observed at each number of cycles, and the evaluation criteria are as follows. The evaluation results are shown in Table 3 below.

[0198] ○: No cracks were produced.

[0199] ×: Cracks develop

[0200] <Impact resistance (circuit board punching)>

[0201] Circuit board punching uses a punching die to apply pressure to a pre-formed circuit board, cutting it into the required size and shape. Commonly used punching dies include circular cuts, straight cuts, and irregular cuts.

[0202] The circuit board punching steps performed in this invention are as follows:

[0203] 1. Preparation: Fix the circuit board on the punch press, select a punching die with a straight cut and adjust its size and position.

[0204] 2. Punching operation: Start the punch press, apply sufficient pressure, and the punching die presses the circuit board into the required shape and size.

[0205] 3. Observe whether there are cracks in the sheet after punching (in general, punching cracks are likely to occur at the junction of the copper surface and the substrate, that is, at the part where there is a height difference).

[0206] The results are shown in Figures 1A and 1B. Figure 1A shows the cracking of the circuit board formed by conventional white ink of Comparative Example 1 after punching (the red lines represent the copper surface (the rectangular part in the lower left of the figure), and the irregular patterns are the cracks that appeared after punching); Figure 1B shows the circuit board formed by ink of Example 1 after punching (no cracks appeared).

[0207] [Table 3]

[0208] As shown in Tables 1 to 3, Examples 1 to 7, by containing specific (B) difunctional polyether polyurethane acrylate and (F) epoxy resin in appropriate amounts in different component systems, can obtain photosensitive resin compositions with excellent evaluations in terms of reflectivity, colorfastness, solder heat resistance, touch drying, drying management range, thermal shock resistance, and external impact resistance.

[0209] In contrast, Comparative Example 1, which did not use (B) difunctional polyether polyurethane acrylate, performed poorly in the thermal shock resistance evaluation, especially after 50 and 75 cycles, resulting in cracking. Comparative Example 2, although using (B) difunctional polyether polyurethane acrylate, used a small amount, so the results in the thermal shock resistance evaluation were not significantly improved, and cracking still occurred after 50 and 75 cycles. Comparative Example 3 used an excessive amount of (B) difunctional polyether polyurethane acrylate; although the thermal shock resistance evaluation was improved, the touch dryness and colorfastness were significantly negatively affected, resulting in a sticky residue. Comparative Example 4… instead of (B) difunctional polyether polyurethane acrylate… Comparative Examples 4 and 5 used 4, 6, and 8 parts by weight of polypropylene glycol diacrylate, respectively. The results showed that the thermal shock resistance of Comparative Examples 4 and 5 was not improved, and cracks still appeared after 50 and 75 cycles. Comparative Example 6 had poor thermal shock resistance and poor touch dryness. Instead of (B) difunctional polyether polyurethane acrylate, Comparative Examples 7 and 8 used trifunctional aliphatic polyurethane acrylate. The results showed that the thermal shock resistance was not significantly improved. Comparative Example 7, which used less aliphatic polyurethane acrylate, still cracked after 50 and 75 cycles, while Comparative Example 8, which used more aliphatic polyurethane acrylate, cracked after 75 cycles.

[0210] The results above demonstrate that the photosensitive resin composition of the present invention exhibits excellent touch-drying properties and drying range. Furthermore, the cured product obtained therefrom also possesses excellent heat resistance, good resistance to thermal shock and external impact, high reflectivity, and excellent colorfastness. The photosensitive resin composition of the present invention is suitable for electronic components requiring miniaturization and high performance.

[0211] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0212] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A photosensitive resin composition comprising at least a two-component resin composition, characterized in that, The photosensitive resin composition comprises: (A) a carboxyl-containing resin, (B) a difunctional polyether polyurethane acrylate, (C) a photosensitive monomer, (D) a photopolymerization initiator, (E) an antioxidant, and (F) an epoxy resin. The carboxyl-containing resin (A) and the difunctional polyether polyurethane acrylate (B) are contained in the first component, and the epoxy resin (F) is contained in a second component that is different from the first component. Relative to 100 parts by weight of the carboxyl-containing resin (A) based on solid content, the difunctional polyether polyurethane acrylate (B) is 1.2 to 11 parts by weight.

2. The photosensitive resin composition according to claim 1, wherein, The second component contains at least the photosensitive monomer (C).

3. The photosensitive resin composition according to claim 1 or 2, wherein, The epoxy resin (F) comprises bisphenol A phenolic varnish type epoxy resin.

4. The photosensitive resin composition according to claim 1 or 2, wherein, The molar ratio of epoxy groups in the second component to carboxyl groups in the first component, i.e., the ratio of epoxy groups in the second component to carboxyl groups in the first component, is 0.8 to 2.

8.

5. The photosensitive resin composition according to claim 1 or 2, wherein, The first component comprises at least one selected from the (C) photosensitive monomer, the (D) photopolymerization initiator, and the (E) antioxidant.

6. The photosensitive resin composition according to claim 5, wherein, The first component comprises the (C) photosensitive monomer, the (D) photopolymerization initiator, and the (E) antioxidant.

7. The photosensitive resin composition according to claim 1 or 2, wherein, The antioxidant (E) is 3.0 to 9.1 parts by weight relative to 100 parts by weight of the carboxyl-containing resin (A) based on solid content.

8. A dry film, characterized in that, It has a resin layer comprising the photosensitive resin composition according to any one of claims 1 to 7.

9. A cured product, characterized in that, It is formed by curing the resin layer of the photosensitive resin composition according to any one of claims 1 to 7 or the dry film according to claim 8.

10. An electronic component comprising the cured material of claim 9.

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