Curable composition and cured layer

Abstract

This disclosure provides a curable composition and a cured layer. The curable composition comprises 100 parts by weight of a first monomer, 1 to 10 parts by weight of a second monomer, 10 to 30 parts by weight of a polyurethane acrylate, and 15 to 35 parts by weight of a blocked isocyanate, wherein the first monomer is a monoacrylate compound, a monomethacrylate compound, a vinyl aromatic compound, an oxetane compound, a maleic anhydride, a dicyclopentadiene, an N-vinylpyrrolidone, an N-vinylformamide, or a combination thereof; and the second monomer is an alcohol compound having at least two reactive functional groups, wherein the reactive functional groups are acrylate groups or methacrylate groups.

Description

Technical Field

[0001] This disclosure relates to a composition and a cured layer formed therefrom. Prior Technology

[0002] In the formation of etch resists, solder resists, and markings on printed circuit boards, the traditional method involves applying a high-viscosity ink composition to the substrate using screen printing. In recent years, to replace screen printing, a method using inkjet printing to spray the ink composition onto the substrate has been developed. The advantages of inkjet printing include reduced ink consumption and the ability to directly draw from digital data. However, the properties of the compositions used in inkjet printing (IJP) processes differ from those conventionally used in screen printing.

[0003] Furthermore, in recent years, the miniaturization and thinning of electronic devices such as mobile phones, cameras, and laptops have been developing. In the manufacturing process of circuit boards, represented by semiconductor packaging substrates, flexible printed circuits (FPCs), or rigid-flexible (RF) substrates, the ink composition used, after inkjet printing, must not only have high adhesion to the substrate, solderability, and chemical resistance, but also be flexural strength to prevent the cured layer from cracking due to bending of the substrate and losing its protective effect.

[0004] Currently, the photocurable inkjet compositions that can be applied to inkjet printing processes are mainly used for rigid boards. The materials are epoxy and phenolic resin derivatives, which are brittle and not resistant to bending after curing.

[0005] Therefore, a novel curable composition is needed to address the problems faced by conventional technologies. Summary of the Invention

[0006] According to embodiments of this disclosure, a composition is provided, for example, a curable composition suitable for inkjet printing (IJP) processes. According to embodiments of this disclosure, the composition comprises 100 parts by weight of a first monomer, 1 to 10 parts by weight of a second monomer, 10 to 30 parts by weight of a polyurethane acrylate, and 15 to 35 parts by weight of a blocked isocyanate, wherein the first monomer is a monoacrylate compound, a monomethacrylate compound, a vinyl aromatic compound, an oxetane compound, maleic anhydride, dicyclopentadiene, N-vinylpyrrolidone, N-vinylformamide, or a combination thereof; and the second monomer is an alcohol compound having at least two reactive functional groups, wherein the reactive functional groups are acrylate groups or methacrylate groups.

[0007] According to the embodiments disclosed herein, a cured layer is also provided, wherein the cured layer is a cured product of the composition disclosed herein. Simple Explanation of the Diagram

[0008] none Implementation

[0009] The following provides a detailed description of the composition and cured layer disclosed herein. It should be understood that the following description provides many different embodiments for implementing different variations of this disclosure. The specific elements and arrangements described below are merely illustrative of this disclosure. Of course, these are illustrative only and not limiting of this disclosure. In this disclosure, the term "about" means an amount that can be increased or decreased by a size that is generally and reasonably understood by one skilled in the art.

[0010] The use of ordinal numbers such as "first," "second," and "third" in the specification and claims to modify the elements of the claims does not imply or represent any prior ordinal number of the claimed element, nor does it represent the order of one claimed element with another, or the order of manufacturing process. The use of these ordinal numbers is only to enable a claimed element with a certain name to be clearly distinguished from another claimed element with the same name.

[0011] The specific embodiments described are merely to illustrate particular ways in which the invention is used and are not intended to limit the invention. Unless otherwise defined, all terms used in this disclosure (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms defined in common dictionaries should be interpreted as having the same meaning as in the relevant art and the content of this disclosure, and that, unless explicitly defined herein, will not be interpreted in an idealized or overly formal sense.

[0012] This disclosure provides a composition, such as a photosensitive curable composition, which can be used to form a patterned film layer using an inkjet printing (IJP) process and then a cured layer using an exposure process. By introducing specific reactive monomers and combining them with specific components and proportions, the composition disclosed herein exhibits a viscosity between 18 cps and 34 cps at 25 °C, making it highly suitable for forming patterned film layers using an inkjet printing (IJP) process. It also demonstrates excellent storage stability (viscosity increase of less than or equal to 1% after 30 days of storage at 60 °C). Furthermore, the cured layer prepared using the composition disclosed herein maintains high chemical resistance, solderability, and adhesion while also exhibiting excellent folding resistance, making it highly suitable for use in printed circuit boards.

[0013] According to an embodiment of this disclosure, a composition is provided. According to an embodiment of this disclosure, the composition comprises 100 parts by weight of a first monomer, 1 to 10 parts by weight (e.g., 1.5 parts by weight, 2 parts by weight, 3 parts by weight, 5 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, or 9 parts by weight) of a second monomer, 10 to 30 parts by weight (e.g., 12 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, or 28 parts by weight) of a polyurethane acrylate, and 15 to 35 parts by weight (e.g., 17 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, or 33 parts by weight) of a blocked isocyanate. According to an embodiment of this disclosure, when the amount of the second monomer is too small, the cured layer prepared by the composition has low chemical resistance, solderability, and adhesion; and when the amount of the second monomer is too large, the cured layer prepared by the composition has high viscosity and is unsuitable for forming patterned film layers using inkjet printing (IJP) processes. According to the embodiments disclosed herein, when the amount of polyurethane acrylate is too small, the resulting film layer has poor folding resistance; and when the amount of polyurethane acrylate is too large, the viscosity of the composition will be too high, which is not conducive to use in inkjet printing processes. According to the embodiments disclosed herein, when the amount of blocked isocyanate compound is too small, the resulting film layer has poor adhesion and solder resist properties; and when the amount of blocked isocyanate compound is too large, the viscosity of the composition will be too high, which is not conducive to use in inkjet printing processes.

[0014] According to the embodiments disclosed herein, the first monomer may be a monoacrylate compound, a monomethacrylate compound, a vinyl aromatic compound, an oxetane compound, maleic anhydride, dicyclopentadiene, N-vinylpyrrolidone, N-vinylformamide, or a combination thereof.

[0015] According to the embodiments disclosed herein, the monoacrylate compound may be methyl acrylate, ethyl acrylate, butyl acrylate, stearyl acrylate, acrylmorpholine, 2-hydroxy-3-acryloxypropyl acrylate, 2-hydroxy-3-phenoxyethyl acrylate, 1,4-cyclohexane dimethanol monoacrylate, methoxy polyethylene glycol monoacrylate, alkoxylated lauryl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, or stearyl acrylate. acrylate), isodecyl acrylate, 2-phenoxyethyl acrylate, 3,3-acrylate5-Trimethylcyclohexyl acrylate, isobornyl acrylate, tridecyl acrylate, ethoxylated nonyl phenol acrylate, octyldecyl acrylate, cyclic trimethylolpropane formal acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, ethylhexyl acrylate, or combinations thereof.

[0016] According to the embodiments disclosed herein, the monomethacrylate compound may be methyl methacrylate, ethyl methacrylate, butyl methacrylate, stearyl methacrylate, methacryloyl morpholine, 2-hydroxy-3-methacryloxypropyl methacrylate, 2-hydroxy-3-phenoxyethyl methacrylate, 1,4-cyclohexane dimethanol monomethacrylate, methoxy polyethylene glycol monomethacrylate, alkoxylated lauryl methacrylate, tetrahydrofuran methacrylate, or lauryl methacrylate. methacrylate), 2-(2-ethoxyethoxy)ethyl methacrylate, stearyl methacrylate, isodecyl methacrylate, 2-phenoxyethyl methacrylate, 3,3-methacrylate5-Trimethylcyclohexyl methacrylate, isobornyl methacrylate, tridecyl methacrylate, ethoxylated nonyl phenol methacrylate, octyldecyl methacrylate, cyclic trimethylolpropane formal methacrylate, hydroxyethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, ethylhexyl methacrylate, or combinations thereof.

[0017] According to the embodiments disclosed herein, the vinyl aromatic compound may be styrene, methylstyrene, chloromethylstyrene, ethylstyrene, cyclohexylstyrene, divinylbenzene, 1-vinyl-5-hexylnaphthalene, vinylnaphthalene, vinylanthracene, or a combination thereof.

[0018] According to the embodiments disclosed herein, the oxetane compound may be xylylene oxetane, hydroxyoxetane, 3-ethyl-3-(phenoxymethyl)oxetane, or a combination thereof.

[0019] According to the embodiments disclosed herein, the first monomer is liquid at room temperature (e.g., about 18 °C to 35 °C), and the second monomer, polyurethane acrylate, and blocked isocyanate compound are soluble or dispersed in the first monomer. Therefore, the composition disclosed herein has flowability at room temperature (e.g., about 18 °C to 35 °C).

[0020] According to embodiments of this disclosure, the second monomer may be an alcohol compound having at least two reactive functional groups, wherein the reactive functional groups may be acrylate groups or methacrylate groups. According to embodiments of this disclosure, the alcohol compound having at least two reactive functional groups may be pentaerythritol diacrylate, pentaerythritol triacrylate (PETIA), dipentaerythritol tetraacrylate (DPPA), dipentaerythritol pentaacrylate (DPPA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, 2-ethyl-2-(hydroxymethyl)-1,3-propanediyl bismethacrylate, or a combination thereof.

[0021] According to the embodiments disclosed herein, the polyurethane acrylate may be an aromatic polyurethane acrylate, an aliphatic polyurethane acrylate, or a combination thereof. According to the embodiments disclosed herein, the polyurethane acrylate may be an aliphatic polyurethane diacrylate, an aliphatic polyurethane triacrylate, an aliphatic polyurethane hexaacrylate, an aromatic polyurethane diacrylate, an aromatic polyurethane hexaacrylate, an aliphatic polyurethane dimethacrylate, an aliphatic polyurethane trimethacrylate, an aliphatic polyurethane hexamethacrylate, an aromatic polyurethane dimethacrylate, an aromatic polyurethane hexamethacrylate, or a combination thereof.

[0022] According to embodiments disclosed herein, the blocked isocyanate compound can be a reaction product of an isocyanate compound multimer and a capping agent. In other words, the blocked isocyanate compound can be an isocyanate compound multimer with a protecting group. According to embodiments disclosed herein, the blocked isocyanate compound is obtained by capping an isocyanate multimer having a biuret structure, a tricyclic isocyanate structure, or an adduct structure using a capping agent. Furthermore, the blocked isocyanate compound disclosed herein can be generated by heating (e.g., 90 °C to 150 °C) to form isocyanate groups.

[0023] The isocyanate compound used to synthesize blocked isocyanate compounds has two or more isocyanate groups in one molecule. For example, isocyanate compounds can be 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and 1,9-nonamethylene diisocyanate. diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,2'-diethyl ether diisocyanate, diphenylmethane-4,4'-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, methylenebis(cyclohexyl isocyanate), 1,3-cyclohexanedimethylene diisocyanate), cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene diisocyanate (1,5-naphthalene diisocyanate), p-phenylene diisocyanate, 3,3'-methylenebis(o-tolyl diisocyanate), 4,4'-diphenyl ether diisocyanate, tetrachlorophenylene diisocyanate, norbornane diisocyanate, hydrogenated 1,3-xylylene diisocyanate, or hydrogenated 1,4-xylylene diisocyanate.

[0024] According to the embodiments disclosed herein, the capping agent forming the capping structure of the blocked isocyanate compound disclosed herein may be an oxime compound, a lactam compound, a phenol compound, an alcohol compound, an amine compound, an active methylene compound, a pyrazole compound, a thiol compound, an imidazole-based compound, or an imide-based compound. For example, the oxime compound may be acetone oxime, formaldoxime, cyclohexane oxime, methyl ethyl ketone oxime, cyclohexanone oxime, benzophenone oxime, or acetone oxime; the lactamine compound may be ε-caprolactam or γ-butyrolactam; the phenol compound may be phenol, naphthol, cresol, or xylenol; the alcohol compound may be methanol, ethanol, propanol, butanol, cyclohexanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, or alkyl lactate; the amine compound may be aniline, diphenylamine, ethyleneimine, or polyethyleneimine; the active methylene compound may be diethyl malonate, dimethyl malonate, ethyl acetoacetate, or methyl acetoacetate; the pyrazole compound may be pyrazole, methylpyrazole, or dimethylpyrazole; and the thiol compound may be alkyl thiol or aryl thiol.

[0025] According to embodiments disclosed herein, the composition may further include 0.1 to 20 parts by weight (e.g., 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 10 parts by weight, or 15 parts by weight) of an initiator, such as a photoinitiator. The photoinitiator may be a benzoin-based compound, an acetophenone-based compound, a thioxanthone-based compound, a ketal compound, a benzophenone-based compound, an α-aminoacetophenone compound, an acylphosphine oxide compound, a biimidazole-based compound, a triazine-based compound, or a combination thereof.

[0026] According to embodiments of this disclosure, acetophenone compounds may be photoinitiators manufactured by Ciba Geigy and with trade names Irgacure 2959, Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 379, Irgacure 907, or Darocur 1173. According to embodiments of this disclosure, the initiator may be a photoinitiator with trade names IRGACURE 819, IRGACURE 1800, Lucirin TPO, or Lucirin TPO-L. According to the embodiments disclosed herein, the initiator may also be a photoinitiator manufactured by LAMBSON with trade numbers Esacure 1001M, Esacure KIP150, Speedcure BEM, Speedcure EHA, Speedcure BMS, Speedcure MBP, Speedcure PBZ, Speedcure ITX, Speedcure DETX, Speedcure EBD, Speedcure MBB, or Speedcure BP, or a photoinitiator manufactured by Ciba Geigy with trade numbers Irgacure 2100, Irgacure 250, or Irgacure 784.

[0027] According to embodiments of this disclosure, the composition comprises a first monomer, a second monomer, an acrylic polyurethane, a blocked isocyanate compound, and an initiator. According to embodiments of this disclosure, the composition may consist of a first monomer, a second monomer, an acrylic polyurethane, a blocked isocyanate compound, and an initiator.

[0028] According to embodiments of this disclosure, the composition may further include 0.1 to 10 parts by weight (e.g., 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, or 8 parts by weight) of a photoacid generating agent. The photoacid generating agent disclosed herein may be an onium salt, triarylsulfonium salts, alkylarylsulfonium salts, diaryliodonium salts, diarylchloronium salts, diarylbromonium salts, sulfonates, diazonium salts, diazonaphthoquinone sulfonate, or a combination thereof.

[0029] According to embodiments of this disclosure, the composition comprises a first monomer, a second monomer, an acrylic polyurethane, a blocked isocyanate compound, an initiator, and a photoacid generator. According to embodiments of this disclosure, the composition may consist of a first monomer, a second monomer, an acrylic polyurethane, a blocked isocyanate compound, an initiator, and a photoacid generator.

[0030] According to embodiments of this disclosure, the additive disclosed herein may be 0.1 to 40 parts by weight (e.g., 1 part by weight, 5 parts by weight, 8 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, or 35 parts by weight). According to embodiments of this disclosure, the additive may be a known additive for curable compositions (e.g., curable compositions applicable to printed circuit board manufacturing processes), such as leveling agents, fillers, colorants (e.g., white pigments, black pigments, green pigments, red pigments, blue pigments, or yellow pigments), dyes, defoamers, flame retardants, viscosity modifiers, thixotropic agents, dispersants, stabilizers, or combinations thereof.

[0031] According to an embodiment of this disclosure, a cured layer is also provided, wherein the cured layer is a cured product of the composition described herein. According to an embodiment of this disclosure, the method for preparing the cured layer may include forming a pattern layer on a substrate using an inkjet printing (IJP) process to form the composition described herein. Subsequently, the pattern layer is subjected to an exposure process, and a baking process is performed as needed to obtain the cured layer. According to an embodiment of this disclosure, the light source for the exposure process may be ultraviolet (UV) light (wavelength may be 150 nm to 400 nm), and the exposure amount may be 50 mj / cm² to 200 mj / cm² (e.g., 70 mj / cm², 100 mj / cm², 120 mj / cm², 150 mj / cm², or 180 mj / cm²).

[0032] To make the above-mentioned contents and other objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings.

[0033] Curable Composition

[0034] Example 1 50 g of 4-acryloyl morpholine (ACMO), 15 g of 2-hydroxyethyl acrylate (2-HEA), 15 g of tetrahydrofurfuryl acrylate (THFA), and 8 g of diphenyl2,4,6-trimethylbenzoyl phosphine oxide (TPO) (as a photoinitiator) were uniformly mixed to obtain a mixture. Next, 2 grams of pentaerythritol triacrylate (trade name: Tianjian 4334), 20 grams of aliphatic polyurethane diacrylate (trade name: GU3010Z, manufactured by Guojing Chemical), 14 grams of isophorone diisocyanate (IPDI) trimer (with 3,5-dimethylpyrazole (DMP) as the end-capping agent (trade name: BI 7951, manufactured by Anfeng Industrial Co., Ltd.), and 9 grams of white titanium dioxide (TiO2) (trade name: RFDO) (average particle size approximately 220 to 300 nm) were added to the mixture in sequence. After thorough mixing, the resulting material was filtered through a 1 μm filter to obtain a curable composition (1).

[0035] Example 2 Example 2 was prepared according to the method of preparing curable composition (1) described in Example 1, except that the amount of pentaerythritol triacrylate was increased from 2 grams to 4 grams, the amount of aliphatic polyurethane diacrylate was reduced from 20 grams to 18 grams, and the amount of isophorone diisocyanate trimer was increased from 14 grams to 16 grams, to obtain curable composition (2).

[0036] Example 3 Example 3 was prepared according to the curable composition (1) described in Example 1, except that the amount of pentaerythritol triacrylate was increased from 2 grams to 4 grams, the amount of aliphatic polyurethane diacrylate was reduced from 20 grams to 15 grams, and the amount of isophorone diisocyanate trimer was increased from 14 grams to 19 grams, to obtain curable composition (3).

[0037] Example 4 Example 4 was prepared according to the method of preparing curable composition (1) described in Example 1, except that the amount of pentaerythritol triacrylate was increased from 2 grams to 4 grams, the amount of aliphatic polyurethane diacrylate was reduced from 20 grams to 10 grams, and the amount of isophorone diisocyanate trimer was increased from 14 grams to 24 grams, to obtain curable composition (4).

[0038] Comparative Example 1 83 g of 1,6-hexanediol diacrylate (trade name SR238NS) was uniformly mixed with 8 g of diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as a photoinitiator to obtain a mixture. Next, 18 grams of bisphenol A diglycidyl ether (trade name: Epon 828), 4 grams of pentaerythritol triacrylate (trade name: Tianjian 4334), 12 grams of isophorone diisocyanate (IPDI) trimer (trade name: BI 7951, manufactured by Anfeng Industrial Co., Ltd.), and 9 grams of white titanium dioxide (TiO2) (trade name: RFDO) (average particle size approximately 220 to 300 nm) were added to the mixture in sequence. After thorough mixing, the resulting material was filtered through a 1 μm filter to obtain a curable composition (5).

[0039] Comparative Example 2 Comparative Example 2 was prepared according to the method for preparing the curable composition (5) described in Comparative Example 1, except that bisphenol A diglycidyl ether (Epon 828) was replaced with 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (trade name DOUBLEMER 421P, manufactured by Double Bond Chemical Co., Ltd.), the amount of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) was reduced from 8 grams to 6 grams, and 2 grams of photoacid generator (trade name CPI® ₋100, manufactured by San-Apro Co., Ltd.) was added, to obtain curable composition (6).

[0040] Comparative Example 3 Comparative Example 3 was prepared according to the method for preparing the curable composition (5) described in Comparative Example 1, except that the amount of bisphenol A diglycidyl ether (Epon 828) was reduced from 18 g to 9 g, 9 g of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (trade name DOUBLEMER 421P, manufactured by Double Bond Chemical Co., Ltd.) was added, the amount of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) was reduced from 8 g to 7 g, and 2 g of photoacid generator (trade name CPI® ₋100, manufactured by San-Apro Co., Ltd.) was added, to obtain the curable composition (7).

[0041] Comparative Example 4 83 g of 1,6-hexanediol diacrylate (trade name SR238NS), 3 g of 2-hydroxyethyl acrylate (2-HEA), 4 g of tetrahydrofurfuryl acrylate (THFA), and 8 g of diphenyl2,4,6-trimethylbenzoyl phosphine oxide (TPO) (as a photoinitiator) were uniformly mixed to obtain a mixture. Next, 38 g of aliphatic polyurethane diacrylate (trade name GU3010Z, manufactured by Guojing Chemical), 4 g of pentaerythritol triacrylate (trade name Tianjian 4334), and 9 g of white titanium dioxide (TiO2) (trade name RFDO) (average particle size approximately 220 to 300 nm) were sequentially added to the mixture. After mixing evenly, the resulting material was filtered through a 1μm filter element to obtain a curable composition (8).

[0042] Comparative Example 5 Comparative Example 5 was prepared according to the method for preparing the curable composition (8) described in Comparative Example 4, except that 38 grams of aliphatic polyurethane diacrylate was replaced with isophorone diisocyanate (IPDI) trimer (trade name BI 7951, manufactured by Anfeng Industrial Co., Ltd.) to obtain curable composition (9).

[0043] Comparative Example 6 Comparative Example 6 was prepared according to the method for preparing the curable composition (5) described in Comparative Example 1, except that the amount of 1,6-hexanediol diacrylate was increased from 83 g to 94 g and isophorone diisocyanate trimer was not added, resulting in a curable composition (10).

[0044] Next, the viscosity of curable compositions (1) to (10) at 25 °C was measured, and the storage stability of curable compositions (1) to (10) was evaluated. The results are shown in Table 1. The storage stability was evaluated as follows: First, the viscosity (V1) of the curable composition at 25 °C was measured. Then, the viscosity (V2) of the curable composition was measured again after being placed at 60 °C for 30 days, and the viscosity increase (V2-V1) of the curable composition was calculated. After being stored at 60 °C for 30 days, if the viscosity increase was less than or equal to 2 cps, it was recorded as 0; if the viscosity increase was greater than 2 cps and less than or equal to 10 cps, it was recorded as 0. [△]; and if the viscosity increase is greater than 10 cps or the composition is non-flowable, it is recorded as X. Viscosity was measured using a high shear rate viscometer (CAP2000 H, Brookfield).

[0045] Table 1 Viscosity @ 25 °C (cps) Storage stability Example 1 Curable composition (1) 33 O Example 2 Curable composition (2) 31 O Example 3 Curable composition (3) 30 O Example 4 Curable composition (4) 28 O Comparative Example 1 Curable composition (5) 35 X Comparative Example 2 Curable composition (6) 32 X Comparative Example 3 Curable composition (7) 33 X Comparative Example 4 Curable composition (8) 50 O Comparative Example 5 Curable composition (9) 40 O Comparative Example 6 Curable composition (10) 42 X

[0046] As shown in Table 1, by using specific composition and proportion, the curable composition disclosed herein has a room temperature viscosity of less than or equal to 33 cps, and after being stored at 60 °C for 30 days, the viscosity increase is less than or equal to 2 cps (less than or equal to 1%), thus exhibiting excellent storage stability.

[0047] Solidified products and property assessment Pattern layers (15±1μm thick) of curable compositions (1) to (10) were formed on copper foil substrates with a polyimide (PI) coating (size 10cm*10cm) using an inkjet printing (IJP) process (printer model KM1020, manufactured by Kyocera). The pattern layers were then exposed using ultraviolet light with a wavelength of 395nm and baked at 150°C to obtain cured layers (1) to (10) disposed on the polyimide coating. The chemical resistance, solderability (at 288°C), folding resistance, and adhesion of the cured layers (1) to (10) were then evaluated, and the results are shown in Table 2. The chemical resistance is evaluated as follows: The cured layer (along with the copper foil substrate) is cut into test pieces (10mm × 100mm) and immersed in sulfuric acid aqueous solution (10wt%) and sodium hydroxide aqueous solution (10wt%) respectively, and stirred at 25 °C. After 20 minutes, the cured layer is removed and observed. If the surface of the cured layer is undamaged, it is recorded as O; if the surface of the cured layer is slightly damaged, it is recorded as △; and if the cured layer is significantly swollen or peeled off from the copper foil substrate, it is recorded as X. The solderability is evaluated as follows: The cured layer (along with the copper foil substrate) is cut into test pieces (10mm × 100mm) and placed in a solder bath at 288 °C. After 10 minutes, the cured layer is removed and observed. If the surface of the cured layer is undamaged, it is recorded as O; if the surface of the cured layer is slightly damaged, it is recorded as △; and if the cured layer is significantly swollen or peeled off from the copper foil substrate, it is recorded as X. The flexural strength was assessed as follows: the cured layer (along with the copper foil substrate) was cut into test pieces (10mm × 100mm) and bent from the center of the test piece with a radius of curvature of 1.0mm (bending angle 180°, load 1 kg, and 3 bends). If the cured layer showed no breakage, it was recorded as O; if the cured layer had minor cracks or damage, it was recorded as △; and if the cured layer fractured over a large area or peeled off from the copper foil substrate, it was recorded as X. Adhesion was assessed using the cross-cut adhesion test (according to ASTM D3359).

[0048] In addition, curable compositions (1) to (10) were applied to paper phenolic laminates (FR-1, 10cm x 10cm) using an inkjet printing (IJP) process (printer model KM1020, manufactured by Kyocera) to form patterned layers (15 ± 1 μm thick). The patterned layers were then exposed using ultraviolet light at a wavelength of 395 nm and baked at 150°C to obtain cured layers (11) to (20) disposed on the phenolic resin. The adhesion of the cured layers (11) to (20) was then evaluated, and the results are shown in Table 2.

[0049] Table 2 Chemical resistance Solderability @288 °C Flexural strength Adhesion Adhesion Example 1 Cured layer (1) O O O 5B Cured layer (11) 5B Example 2 Cured layer (2) O O O 5B Cured layer (12) 5B Example 3 Curing layer (3) O O O 5B Cured layer (13) 5B Example 4 Cured layer (4) O O O 5B Cured layer (14) 5B Comparative Example 1 Cured layer (5) O O X 0B Cured layer (15) 4B Comparative Example 2 Cured layer (6) O O △ 1B Cured layer (16) 4B Comparative Example 3 Cured layer (7) O O △ 1B Cured layer (17) 4B Comparative Example 4 Cured layer (8) X X X 4B Cured layer (18) 5B Comparative Example 5 Cured layer (9) O O X 5B Cured layer (19) 4B Comparative Example 6 Cured layer (10) O O X 1B Cured layer (20) 1B

[0050] As shown in Table 2, by using specific composition and proportion, the cured layer obtained by using the curable composition disclosed herein has good chemical resistance, solderability and adhesion, as well as 180-degree flexural strength, making it suitable for forming patterned layers on flexible / bendable substrates using inkjet printing processes.

[0051] In summary, by introducing specific reactive monomers and combining them with specific components and proportions, the composition disclosed herein exhibits a viscosity between 18 cps and 34 cps at 25 °C, making it highly suitable for forming patterned films using inkjet printing (IJP) processes. It also demonstrates excellent storage stability (viscosity increase of less than or equal to 1% after 30 days of storage at 60 °C). Furthermore, the cured layer prepared using the composition disclosed herein maintains high chemical resistance, solderability, and adhesion while also exhibiting excellent folding resistance, making it ideal for use in printed circuit boards.

[0052] Although this disclosure has been presented above with reference to several embodiments, it is not intended to limit this disclosure. Anyone skilled in the art can make any modifications and alterations without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.

[0053] none

Claims

1. A curable composition comprising: 100 parts by weight of a first monomer, wherein the first monomer is a monoacrylate compound, a monomethacrylate compound, a vinyl aromatic compound, an oxetane compound, maleic anhydride, dicyclopentadiene, N-vinylpyrrolidone, N-vinylformamide, or a combination thereof; 1 to 10 parts by weight of a second monomer, wherein the second monomer is an alcohol compound having at least two reactive functional groups, wherein the reactive functional groups are acrylate or methacrylate groups; 10 to 30 parts by weight of a polyurethane acrylate; and 15 to 35 parts by weight of a blocked isocyanate compound.

2. The curable composition as claimed in claim 1, wherein the curable composition has a viscosity of 18 cps to 34 cps at 25°C.

3. The curable composition as claimed in claim 1, wherein the monoacrylate compound is methyl acrylate, ethyl acrylate, butyl acrylate, stearyl acrylate, acrylmorpholine, 2-hydroxy-3-acryloxypropyl acrylate, 2-hydroxy-3-phenoxyethyl acrylate, 1,4-cyclohexane dimethanol monoacrylate, methoxy polyethylene glycol monoacrylate, alkoxylated lauryl acrylate, tetrahydrofuran acrylate, lauryl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate. acrylate), stearyl acrylate, isodecyl acrylate, 2-phenoxyethyl acrylate, 3,3-acrylate5-Trimethylcyclohexyl acrylate, isobornyl acrylate, tridecyl acrylate, ethoxylated nonyl phenol acrylate, octyldecyl acrylate, cyclic trimethylolpropane formal acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, ethylhexyl acrylate, or combinations thereof.

4. The curable composition as claimed in claim 1, wherein the monomethacrylate compound is methyl methacrylate, ethyl methacrylate, butyl methacrylate, stearyl methacrylate, methacryloyl morpholine, 2-hydroxy-3-methacryloxypropyl methacrylate, 2-hydroxy-3-phenoxyethyl methacrylate, 1,4-cyclohexane dimethanol monomethacrylate, methoxy polyethylene glycol monomethacrylate, alkoxylated lauryl methacrylate, tetrahydrofuran methacrylate, or lauryl methacrylate. methacrylate), 2-(2-ethoxyethoxy)ethyl methacrylate, stearyl methacrylate, isodecyl methacrylate, 2-phenoxyethyl methacrylate, 3,3-methacrylate5-Trimethylcyclohexyl methacrylate, isobornyl methacrylate, tridecyl methacrylate, ethoxylated nonyl phenol methacrylate, octyldecyl methacrylate, cyclic trimethylolpropane formal methacrylate, hydroxyethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, ethylhexyl methacrylate, or combinations thereof.

5. The curable composition as claimed in claim 1, wherein the vinyl aromatic compound is styrene, methylstyrene, chloromethylstyrene, ethylstyrene, cyclohexylstyrene, divinylbenzene, 1-vinyl-5-hexylnaphthalene, vinylnaphthalene, vinylanthracene, or a combination thereof.

6. The curable composition as claimed in claim 1, wherein the oxetane compound is xylylene oxetane, hydroxyoxetane, 3-ethyl-3-(phenoxymethyl)oxetane, or a combination thereof.

7. The curable composition as claimed in claim 1, wherein the alcohol compound having at least two reactive functional groups is pentaerythritol diacrylate, pentaerythritol triacrylate (PETIA), dipentaerythritol tetraacrylate (DPPA), dipentaerythritol pentaacrylate (DPPA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, 2-ethyl-2-(hydroxymethyl)-1,3-propanediyl bismethacrylate, or a combination thereof.

8. The curable composition as claimed in claim 1, wherein the polyurethane acrylate is an aromatic polyurethane acrylate, an aliphatic polyurethane acrylate, or a combination thereof.

9. The curable composition as claimed in claim 1, wherein the blocked isocyanate compound is a reaction product of a polymer of an isocyanate compound and a capping agent.

10. The curable composition as claimed in claim 1, further comprising: 1-20 parts by weight of an initiator.

11. A cured layer, wherein the cured layer is a cured product of the curable composition described in any one of claims 1 to 10.