A polymer resin, a low-temperature-curable resin composition containing the same, and applications thereof

Abstract

This invention provides a polymer resin and a low-temperature curable resin composition containing the polymer resin. The polymer resin has repeating units shown in Formula I, repeating units shown in Formula II, and structural units shown in Formula III. The cured film of the polymer resin composition has high visible light transmittance, good development effect, good adhesion to metal surfaces, good solvent resistance, and a certain degree of toughness, resulting in good application performance.

Description

Technical Field

[0001] This invention belongs to the field of photocuring technology, and relates to a polymer resin, a low-temperature curable resin composition containing the polymer resin, and its applications. Background Technology

[0002] In recent years, with the rapid development of emerging technologies such as artificial intelligence, foldable devices, and brain-computer interfaces, display components have gradually moved towards high definition and flexibility, thus placing higher demands on related manufacturing materials. In particular, the requirements for flexible wearable devices place higher demands on the precision of pattern formation, photosensitivity, adhesion of cured films, and bendability. To meet these application needs, special designs are often required for the structure of materials to achieve high curing strength, development sensitivity, and weather resistance in the cured composition. However, the substrates to which these materials are attached often cannot withstand the high post-baking temperatures (230°C) like glass substrates. Therefore, lower curing temperature requirements have been placed on some adhesives and curing compositions. Japanese Patent Application Publication No. 2008-143954 proposes using a polymer containing isocyanate rings as a semiconductor adhesive, achieving bonding by heating in an oven at 50-250°C for 0.5-4 hours, but its curing efficiency is not high.

[0003] CN107709388A proposes a polymer containing double bonds prepared by epoxy copolymerization of isocyanuric acid diepoxy groups and other bifunctional (such as hydroxyl) monomers. This polymer is then used for free radical polymerization to prepare a related photocurable composition, resulting in a cured film with high visible light transmittance and excellent heat and solvent resistance at temperatures below 200°C. This cured film can be used as a lens material. However, its post-curing development properties are not mentioned. Furthermore, due to the use of a free radical curing process, there may be some oxygen inhibition, making rapid surface drying difficult and potentially affecting adhesion and encapsulation performance. Summary of the Invention

[0004] The present invention aims to provide a polymer resin, a low-temperature curable resin composition containing the same, and its applications. The low-temperature curable resin composition has a low curing temperature, and the cured film exhibits good development accuracy, high visible light transmittance, good adhesion to metal layers such as copper, and good bendability, thus meeting the requirements for bonding and development precision in flexible substrate electronic devices.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a polymer resin having repeating units as shown in Formula I and Formula II.

[0007]

[0008] R1 and R2 independently represent H, C1-C10 alkyl groups; R3 represents C1-C10 alkyl groups, C1-C10 alkoxy groups, C3-C20 cycloalkyl groups, and C6-C12 aromatic groups; m represents an integer from 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10), and n represents an integer from 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0009] R4 and R5 each independently represent C1-C10 alkylene, C1-C10 alkeneoxy, and C3-C10 cycloalkylene; R6 and R7 each independently represent H and C1-C10 alkyl; l represents an integer from 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0010] In this invention, to address the need for rapid low-temperature curing, the polymer structure is adjusted to obtain a polymer with a specific structure, and a corresponding photocurable composition is prepared. This results in a photocurable composition that can cure at low temperatures, exhibits good adhesion to substrates and metal coatings, cures quickly, produces fine patterns, and has good toughness. It can be easily applied to form patterns on flexible substrates for bonding, encapsulation, and other applications, and also possesses good visible light transmittance and solvent resistance.

[0011] In this invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10, C3-C20 can be C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C15, C16, C18 or C20, and C6-C12 can be C6, C7, C8, C9, C10, C11 or C12.

[0012] The polymer resin of the present invention has the above-mentioned repeating structure, wherein the oxobutane side group, after curing, can provide a certain toughness while forming a cured product with a high crosslinking density, thereby improving the bending resistance of the cured film.

[0013] The polymerization unit shown in Formula II can provide the polymer with a faster curing rate and a higher crosslinking density. The resulting cured film has high visible light transmittance and good adhesion to metal materials, which is beneficial for adding metals to the substrate or preparing more intricate patterns.

[0014] To obtain better hardness, solvent resistance, and certain alkali solubility, the polymer resin provided by this invention also contains structural units as shown in Formula III:

[0015]

[0016] Among them, R8 represents H, acetyl or alkoxyacyl, etc.; R9, R 10 H and C1-C10 alkyl groups are represented independently; k represents an integer from 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10).

[0017] To achieve better alkali solubility, the polymer resin provided by this invention also contains a certain amount of repeating units with carboxyl groups. There are no particular limitations here, as long as carboxyl groups can be provided. This repeating unit can be polymerized from compounds having carboxylic acid groups and unsaturated double bonds (such as any one or a combination of at least two of the following: methacrylic acid, acrylic acid, 1-vinylpentanoic acid, succinic acid mono-2-(2-acryloyloxy)hydroxyethanol, etc.).

[0018] In addition, to adjust the application effect of polymer resin, repeating units can be obtained by adding acrylate epoxy compounds, such as: glycidyl acrylate, propyl glycidyl acrylate, butyl glycidyl acrylate, β-ethyl glycidyl acrylate, glycidyl methacrylate, propyl glycidyl methacrylate, β-glycidyl methacrylate, etc., one or at least two of which are polymerized together.

[0019] On the other hand, the present invention provides a method for preparing the polymer resin as described above, the method comprising the following steps:

[0020] The product is obtained by copolymerization of unsaturated carboxylic acids, monomeric compounds of repeating units shown in Formula I, monomeric compounds of repeating units shown in Formula II, and optionally monomeric compounds of repeating units shown in Formula III.

[0021] Preferably, the mass ratio of the unsaturated carboxylic acid, the monomeric compound of the repeating unit shown in Formula I, the monomeric compound of the repeating unit shown in Formula II, and the monomeric compound of the repeating unit shown in Formula III is (15-20):(10-16):(5-18):(5-20); wherein the mass percentage of the unsaturated carboxylic acid 15-20 can be 15, 16, 17, 18, 19, or 20, etc.; the mass percentage of the monomeric compound of the repeating unit shown in Formula I 10-16 can be 10, 11, 12, 13, 14, 15, or 16; the mass percentage of the monomeric compound of the repeating unit shown in Formula II 5-18 can be 5, 7, 9, 10, 12, 14, 16, or 18, etc.; and the mass percentage of the monomeric compound of the repeating unit shown in Formula III 5-20 can be 5, 6, 8, 10, 13, 15, 17, or 20, etc.

[0022] The polymer resin provided by this invention also includes unsaturated compounds with cyclic structures and other monomers in its raw materials. After copolymerization, it forms a cured composition to improve the hardness of the film and enhance the material's application properties such as scratch resistance and etching resistance.

[0023] Exemplarily, the other monomers include any one or a combination of at least two of the following: alkyl methacrylates (such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, etc.), alkyl acrylates (such as butyl acrylate), hydroxyl-containing (meth)acrylates (such as hydroxyethyl methacrylate), aryl methacrylates, substituted alkyl methacrylates, alkenyl-containing monomers (such as styrene, 1-hexene, 4-ethoxystyrene, etc.), or maleimide compounds (such as N-phenylmaleimide), more preferably methyl methacrylate and / or ethyl methacrylate.

[0024] The polymer provided by the present invention is obtained by free radical copolymerization, and the initiator used in the copolymerization includes peroxide initiators or azo initiators.

[0025] Preferably, the peroxide initiator includes any one or a combination of at least two of benzoyl peroxide, ethyl hexanoate peroxide, cumene peroxide, hydrogen peroxide, or potassium persulfate.

[0026] Preferably, the azo initiator includes any one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, and azobisisovalerate.

[0027] The resin containing the relevant structural units provided by this invention can be easily obtained by copolymerization reaction with the corresponding monomers, and the molecular weight of the polymer resin can be controlled during the synthesis process.

[0028] The weight-average molecular weight of the polymer resin of the present invention is 8,000-20,000, for example 8,000, 9,000, 10,000, 12,000, 15,000, 18,000 or 20,000, preferably 8,000-15,000, and more preferably 10,000-12,000.

[0029] The weight-average molecular weight of the polymer was determined using GPC (gel permeation chromatography), specifically by converting the weight-average molecular weight of polystyrene standards.

[0030] In another aspect, the present invention provides a method for preparing a polymer resin, comprising the following steps:

[0031] An unsaturated carboxylic acid, a monomeric compound of repeating unit shown in Formula I, a monomeric compound of repeating unit shown in Formula II, and optionally a monomeric compound of repeating unit shown in Formula III are mixed and polymerized under the initiation of an initiator to obtain the polymer resin.

[0032] Preferably, the unsaturated carboxylic acid is selected from methacrylic acid and / or acrylic acid.

[0033] Preferably, the monomeric compound of the repeating unit shown in Formula I is selected from oxetane acrylate and / or 2-((3-ethyloxetane)yl)methoxy)ethyl methacrylate;

[0034] Preferably, the monomeric compound of the repeating unit shown in Formula II is selected from 1-vinyl-3,5-diglycidyl isocyanurate and / or 1-propenyl-3,5-diglycidyl isocyanurate;

[0035] Preferably, the monomeric compound of the repeating unit shown in Formula III is selected from 4-vinylphenol acetate and / or 4-isopropenylphenol, etc.

[0036] Preferably, the polymerization reaction is carried out in a solvent, such as: dipropylene glycol monomethyl ether, dipropylene glycol methyl ethyl ether, ethyl 2-oxobutyrate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, n-propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, butyl butyrate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxy-2-methyl... The following are options: ethyl 3-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxypropionate, methyl ethyl ketone, cyclohexanone, heptanone, 3-heptanone, tetrahydrofuran, pyran or γ-butyrolactone, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methyl-3-methoxybutylacetate, 3-methyl-3-methoxybutylpropionate, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, or a combination of at least two of these options. More preferably, they are options: propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, or a combination of at least two of these options. Even more preferably, they are propylene glycol methyl ether acetate and / or diethylene glycol methyl ethyl ether.

[0037] Preferably, the polymerization reaction is carried out in the presence of an inert gas, which includes any one of nitrogen, helium or argon, and is preferably nitrogen.

[0038] Preferably, the polymerization reaction is carried out at a temperature of 60-100°C, such as 60°C, 70°C, 80°C, or 90°C. A preferred temperature is 70-80°C.

[0039] On the other hand, the present invention provides a photosensitive resin composition comprising a polymer resin, a photopolymerizable compound, and a photopolymerization initiator provided by the present invention.

[0040] The photosensitive resin composition provided by this invention has radiation sensitivity and heat sensitivity, low curing temperature, good development effect, excellent chemical resistance, good adhesion of the cured film to the metal circuit, and good light transmittance (visible light) of the cured film.

[0041] Preferably, the photosensitive resin composition comprises the following components in parts by weight: 20-50 parts (e.g., 20, 23, 25, 30, 33, 35, 38, 40, 43, 45, 48 or 50 parts) of the polymer resin described in the first aspect, 10-30 parts (e.g., 10, 13, 15, 18, 20, 23, 25, 28 or 30 parts) of the photopolymerization initiator, and 1-5 parts (e.g., 1, 2, 3, 4 or 5 parts) of the photopolymerization initiator.

[0042] Preferably, the photosensitive resin composition further includes 0-3 parts of an auxiliary agent (e.g., 0 parts, 1 part, 2 parts, or 3 parts).

[0043] Preferably, the photosensitive resin composition further includes 12-69 parts of solvent, such as 12 parts, 15 parts, 18 parts, 20 parts, 25 parts, 28 parts, 30 parts, 35 parts, 38 parts, 40 parts, 45 parts, 48 ​​parts, 50 parts, 55 parts, 60 parts, 65 parts, or 69 parts.

[0044] Preferably, the photosensitive resin composition comprises the following components in parts by weight: 30-40 parts of the polymer resin described in the first aspect, 20-25 parts of the photopolymerizable compound, 1-3 parts of the photopolymerization initiator, and 0-1 parts of the additives.

[0045] The photosensitive resin composition provided by this invention utilizes photopolymerizable compounds to improve the photocuring properties, crosslinking properties, and chemical resistance of the cured composition. There are no particular limitations on the photopolymerizable compounds, as long as they are compounds with one or more unsaturated bonds within their molecules.

[0046] Preferably, the photopolymerizable compound includes any one or a combination of at least two of acrylamide compounds, acrylate compounds, or vinyl compounds.

[0047] Preferably, the acrylamide compound includes any one or a combination of at least two of N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, N-hydroxymethylacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-isopropylmethacrylamide, N-hydroxymethylmethacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dimethylmethacrylamide, or N,N-diethylmethacrylamide.

[0048] Preferably, the acrylate compounds may be exemplified as follows: methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethoxytrimethacrylate, trimethylolpropane propoxytrimethacrylate, bisphenol A polyoxyethylene dimethacrylate, bisphenol A dioxyethylene dimethacrylate, and bisphenol A trioxyethylene dimethacrylate. The following are any one or more combinations of bisphenol A oxyvinyl dimethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol hexaacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxy triacrylate, trimethylolpropane propoxy triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, bisphenol A polyoxyethylene diacrylate, bisphenol A dioxyethylene diacrylate, bisphenol A trioxyethylene diacrylate, or bisphenol A oxyvinyl diacrylate.

[0049] Preferably, the vinyl compound comprises any one or a combination of at least two of N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, or N-vinylimidazole.

[0050] Preferably, the photopolymerization initiator includes any one or a combination of at least two of the following: benzophenone initiators, triazine initiators, dialkoxyacetophenone initiators, α-hydroxyalkylphenyl ketone initiators, α-aminealkylphenyl ketone initiators, acylphosphine oxide initiators, benzophenone initiators, benzoin initiators, benzoyl initiators, heterocyclic aromatic ketone initiators, or oxime ester photoinitiators.

[0051] Examples of photopolymerization initiators include: benzophenone, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, diethoxyacetophenone, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, benzoin, benzoin methyl ether, benzoin isobutyl ether, 2-ethyl-9,10-dimethoxyanthracene, 9,10-dimethoxyanthracene, 1-[4-(phenylthio)phenyl]-1,2-octanedione, 2-(O-benzoyl oxime), 2,4,5-triazine, etc. Arylimidazolium dimer, 4,4'-bis(diethylamino)benzophenone, 4,4'-dichlorobenzophenone, 2-methylthioxanthone, 2-isopropylthioxanthone, 10-butyl-2-chloroacridone, o-ethoxycarbonyl-α-oximino-1-phenylpropanone, 1,2-octanedione, dibenzocycloheptanone, trichloroacetophenone, pentyl-4-dimethylaminobenzoate, 9-phenylacridinium, 1,7-di(9-acridyl)heptane, 2,4-bis(trichloromethyl)-6-(2-bromo-4-methoxy)styrenephenyl- s-triazine, 4-benzoyl-4'-methyldimethyl sulfide, 1,3-di(9-acridyl)propane, 2-methyl-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(furan-2-yl)vinyl]-4,5-bis(trichloromethyl)-s-triazine, 2-[2-(4-diethylamino-2-methylphenyl)vinyl]-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-(2-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis( Trichloromethyl)-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine, ethyl 4-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, benzyl-β-methoxyethyl acetal, 1-(4-phenylthio)phenyl-2-(o-benzoyl oxime), 1-(9-ethyl)-6-(2-methylbenzoyl)carbazole-3-yl-1-(O-acetyl oxime), benzyl dimethyl ketal, or 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl) oxime, or any one or a combination of at least two of these.

[0052] A solvent may also be added to the photosensitive resin composition of the present invention. The amount of solvent added shall be selected by those skilled in the art based on experience and process requirements, so that the resin composition reaches a suitable viscosity and is evenly dispersed, so as to facilitate subsequent processing.

[0053] Preferably, the solvent comprises any one or a combination of at least two of alkylene glycol monoalkyl ethers, amides, carboxylic acid esters, ketones, cyclic ethers, or cyclic esters, and more preferably, alkylene glycol monoalkyl ethers. Examples include propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, or diethylene glycol methyl ethyl ether, and more preferably, propylene glycol methyl ether acetate or diethylene glycol methyl ethyl ether.

[0054] In another aspect of the invention, the photosensitive resin composition further comprises an additive, said additive including any one or a combination of at least two of fillers, curing agents, leveling agents, adhesion promoters, antioxidants, or ultraviolet absorbers. Preferably, the additive accounts for 0.01-1.0 parts by weight.

[0055] The photosensitive resin composition provided by this invention has good low-temperature curing properties, and its cured film exhibits good adhesion to metal circuits and excellent visible light transmittance. Simultaneously, it demonstrates good solvent resistance and corrosion resistance, providing effective protection and isolation. Furthermore, the cured film exhibits good development accuracy and flexibility, meeting the requirements for bonding flexible substrates to electronic devices.

[0056] The curing of the curable resin composition provided by this invention includes photocuring and thermal curing processes, enabling deep curing of the cured film at a relatively low temperature during the baking process after exposure. The curing temperature is relatively low, generally below 180°C, such as 180°C, 150°C, 130°C, 100°C, 80°C, 50°C, 30°C, 20°C, etc., with a preferred temperature of 80-150°C, and more preferably 90-130°C.

[0057] On the other hand, the present invention provides a photosensitive resin laminate, characterized in that the photosensitive resin laminate comprises a photosensitive resin layer formed by the photosensitive resin composition as described above and a support supporting the photosensitive resin layer.

[0058] On the other hand, the present invention provides the application of the photosensitive resin composition or the photosensitive resin laminate as described above in the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frames, and semiconductor packages.

[0059] The present invention has the following beneficial effects:

[0060] The photosensitive resin composition containing the polymer resin described in this invention has a cured film with high visible light transmittance, good development effect, good adhesion to metal surfaces, good solvent resistance, and a certain degree of toughness, resulting in good application performance. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0062] The polymer resins provided by this invention are mainly obtained by copolymerizing the corresponding monomers to obtain the polymer resins of Examples 1-6; in addition, comparative polymer resins 7-10 are obtained by removing the polymerizable monomers corresponding to the polymeric units with specific structures, as listed in Table 1.

[0063] Polymer Preparation Example 1

[0064] The monomers were mixed evenly according to the proportions in Table 1 to obtain a monomer mixture for later use. A certain amount of initiator was thoroughly mixed with a certain amount of solvent to form an initiator solution. 100g of propylene glycol methyl ether acetate (PGMEA) was added to a 500mL four-necked flask equipped with a stirrer, condenser, constant pressure dropping funnel, thermometer and nitrogen inlet. Nitrogen gas was introduced and the mixture was heated to 70℃ under stirring. The monomer mixture and initiator solution were added dropwise simultaneously over a period of 2 hours. After the addition was completed, the mixture was kept at this temperature for 2 hours and then cooled to room temperature to obtain the polymer resin (numbered 1-10). The molecular weight of the sample was determined by gel permeation chromatography (GPC) using polystyrene standards as a reference.

[0065] Table 1. List of Example and Comparative Example Proportions

[0066]

[0067] To further determine the application effect of the polymer-based photocurable composition, a photocurable composition was prepared using the following ratio, with reference to Application Example 1 for the specific ratio.

[0068] Application Example 1

[0069] A photosensitive resin composition, by weight, comprises 40 parts of the polymer resin obtained in the examples, 30 parts of the photopolymerizable monomer dipentaerythritol hexamethacrylate, 1.5 parts of the photopolymerization initiator 1-phenyl-1,2-propanedione-2(O-ethoxycarbonyl) oxime, 0.1 parts of the leveling agent BYK307, and 28.4 parts of the solvent propylene glycol monomethyl ether.

[0070] Referring to the formulation shown in Application Example 1, photocurable compositions for Application Examples 1-6 and Comparative Examples 1-4 were prepared, and the specific formulations are listed in Table 2 below.

[0071] Table 2 Application Example Composition Table

[0072]

[0073] To evaluate the application effect of the photocurable composition, the above-mentioned photosensitive resin composition was coated onto a 100mm × 100mm copper-plated PET substrate and pre-baked at 90°C for 90 seconds. Then, it was exposed using a mirror projection device. The exposed sample coating was developed in a 0.04% by mass KOH aqueous solution at 25°C and then baked at 120°C for 30 minutes to form a pattern. The relevant application performance was then evaluated.

[0074] (1) Evaluation of development effect

[0075] The developed pattern was observed using an electron scanning microscope to evaluate the linearity of the development and to determine the adhesion between the pattern and the substrate based on the pattern integrity.

[0076] The evaluation criteria are as follows:

[0077] ①Straightness of developing lines:

[0078] ○: The edges of the pattern lines are almost free of jagged edges;

[0079] △: The edges of the pattern lines have a few jagged edges;

[0080] ╳: The edges of the pattern lines have many defects.

[0081] ② Adhesion between the pattern and the substrate:

[0082] ○: Not peeled off from the substrate, forming a linear pattern;

[0083] △: Although a linear pattern was formed, the pattern was damaged;

[0084] ╳: Peeled off from the substrate without forming a linear pattern.

[0085] (2) Solvent resistance

[0086] The sample coated as described above was deposited onto a glass substrate to form a film. After baking at 90°C for 90 seconds, followed by exposure and baking at 120°C for 30 minutes, the film thickness (H1) was measured. The cured material was then immersed in propylene glycol methyl ether acetate at 50°C for 10 minutes. After drying the solvent, the film thickness (H2) was measured again. The change rate of film thickness before and after immersion was calculated as: (H2-H1) / H1*100%. The solvent resistance was determined based on the change in film thickness, using the following criteria:

[0087] ○: Rate of change ≤ 5%;

[0088] △: 10% ≥ rate of change > 5%;

[0089] ×: Rate of change > 10%.

[0090] (3) Toughness of the cured film of the composition

[0091] The above-mentioned photosensitive resin composition was coated onto a PET substrate (100mm × 100mm) with a copper plating layer and pre-baked at 90°C for 90 seconds. Then, exposure was performed using a mirror projection device aligned with the exposure unit. The exposed sample coatings were developed in a 0.04% (w / w) KOH aqueous solution at 25°C and then baked at 120°C for 30 minutes to form patterns. The cured films prepared in each example and comparative example were tested using an XHS-ZW-03A repeated bending machine. The test conditions were as follows: one end of the cured film to be tested was clamped with a clamp with semi-rounded corners of radii of 1mm, 3mm, and 5mm, and the other end was clamped onto a crankshaft. Driven by a motor, the conductive film was repeatedly bent at a bending frequency of once per second. The appearance of the cured film after 200,000 bends was recorded, and the evaluation criteria were as follows:

[0092] ○: No cracks;

[0093] ╳: There are cracks.

[0094] (4) Visible light transmittance

[0095] After forming a thin film pattern on a PET substrate using the above coating and exposure method, the transmittance is measured using a UV-Vis spectrophotometer at a detection wavelength of 400 nm, with specific measurement standards.

[0096] ○: Transmittance > 95%;

[0097] △: 90% ≤ transmittance ≤ 95%;

[0098] X: Transmittance < 90%.

[0099] The evaluation results are shown in Table 3.

[0100] Table 3

[0101] linearity Adhesion Solvent resistance toughness Visible light transmittance Application Example 1 ○ ○ ○ ○ ○ Application Example 2 ○ ○ ○ ○ ○ Application Example 3 ○ ○ ○ ○ ○ Application Example 4 ○ ○ ○ ○ ○ Application Example 5 ○ △ ○ ○ ○ Application Example 6 △ ○ ○ ○ ○ Comparative Example 1 ○ △ △ ╳ ╳ Comparative Example 2 △ ╳ △ ╳ ╳ Comparative Example 3 ╳ △ △ △ △ Comparative Example 4 △ ╳ ╳ ╳ ╳

[0102] The test results show that the polymer resin and photosensitive resin combination provided by this invention can be cured at a relatively low post-baking temperature, and the resulting pattern has good development effect, excellent pattern linearity, and good visible light transmittance. The cured film has good solvent resistance and adhesion to metal substrates. In addition, the cured film has good toughness, which is beneficial to the preparation of related flexible equipment and has good application prospects.

[0103] Compared to the examples, the comparative examples attempted to remove some monomers, and the application effects were compared with those of the examples. The application effects of the comparative examples were significantly worse. In particular, the oxetane monomers were removed during the polymerization of the polymer in Comparative Example 1, and the toughness of the cured film of the composition prepared with the above polymer was significantly reduced. In addition, due to the loss of the crosslinking regulation effect of oxetane substances, the light transmittance of the cured film was also affected.

[0104] In Comparative Example 2, the epoxy monomer containing the triisocyanuric acid ring was removed during polymer polymerization. The composition prepared using the above polymer showed a significant decrease in the adhesion of the cured film to materials such as metals and the transmittance of visible light.

[0105] In Comparative Example 3, the polymer monomers containing phenolic hydroxyl groups were removed during polymer polymerization. The overall performance of the cured film of the composition prepared using the above polymer decreased, with a significant reduction in linearity of development.

[0106] In Comparative Example 4, the polymer polymerization process removed monomers containing oxocyclic butanes, epoxy monomers containing triisocyanuric acid rings, and polymerizable monomers containing phenolic hydroxyl groups. The compositions prepared using these polymers exhibited significantly reduced adhesion, linearity of development, toughness, and visible light transmittance in their cured films. Overall, their application performance deteriorated.

[0107] By comparing the application effects of the above examples and comparative examples, we can see that the curable composition prepared using the polymer provided by the present invention has better application effects and better application prospects.

[0108] The applicant declares that the present invention is illustrated through the above embodiments to demonstrate the polymer resin of the present invention, the low-temperature curable resin composition containing the polymer resin, and their applications. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the products of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polymer resin, characterized in that, The polymer resin has repeating units as shown in Formula I and Formula II. Where R1 and R2 independently represent H, C1-C10 alkyl groups respectively; R3 represents C1-C10 alkyl groups, C1-C10 alkoxy groups, C3-C20 cycloalkyl groups, and C6-C12 aromatic groups; m represents an integer from 1 to 10, and n represents an integer from 1 to 10. R4 and R5 each independently represent C1-C10 alkylene, C1-C10 alkeneoxy, and C3-C10 cycloalkylene; R6 and R7 each independently represent H and C1-C10 alkyl; l represents an integer from 1 to 10.

2. The polymer resin according to claim 1, characterized in that, The polymer resin also contains structural units as shown in Formula III: Among them, R8 represents H, acetyl or alkoxyacyl, etc.; R9, R 10 H and C1-C10 alkyl groups are represented independently; k represents an integer from 1 to 10.

3. The polymer resin according to any one of claims 1-2, characterized in that, The polymer resin also contains repeating units with carboxyl groups; Preferably, the repeating unit with a carboxyl group is obtained by polymerization of a compound having a carboxylic acid group and an unsaturated double bond; Preferably, the polymer resin further comprises repeating units derived by polymerization of acrylate epoxy compounds; Preferably, the acrylate epoxy compound is selected from one or a combination of at least two of glycidyl acrylate, propyl glycidyl acrylate, butyl glycidyl acrylate, β-ethyl glycidyl acrylate, glycidyl methacrylate, propyl glycidyl methacrylate, or β-glycidyl methacrylate.

4. The polymer resin according to any one of claims 1-3, characterized in that, The polymer resin has a weight-average molecular weight of 8,000-20,000, preferably 8,000-15,000, and more preferably 10,000-12,000.

5. The method for preparing the polymer resin according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: The product is obtained by copolymerization of unsaturated carboxylic acids, monomeric compounds of repeating units shown in Formula I, monomeric compounds of repeating units shown in Formula II, and optionally monomeric compounds of repeating units shown in Formula III. Preferably, the mass ratio of the unsaturated carboxylic acid, the monomeric compound of the repeating unit shown in Formula I, the monomeric compound of the repeating unit shown in Formula II, and the monomeric compound of the repeating unit shown in Formula III is (15-20):(10-16):(5-18):(5-20). Preferably, the unsaturated carboxylic acid is selected from methacrylic acid and / or acrylic acid; Preferably, the monomeric compound of the repeating unit shown in Formula I is selected from oxetane acrylate and / or 2-((3-ethyloxetane)yl)methoxy)ethyl methacrylate; Preferably, the monomeric compound of the repeating unit shown in Formula II is selected from 1-vinyl-3,5-diglycidyl isocyanurate and / or 1-propenyl-3,5-diglycidyl isocyanurate; Preferably, the monomeric compound of the repeating unit shown in Formula III is selected from 4-vinylphenol acetate and / or 4-isopropenylphenol; Preferably, the polymerization reaction is carried out at a temperature of 60-100°C, and more preferably at a temperature of 70-80°C.

6. A photosensitive resin composition, characterized in that, The photosensitive resin composition comprises the polymer resin, photopolymerizable compound, and photopolymerization initiator as described in any one of claims 1-5.

7. The photosensitive resin composition according to claim 6, characterized in that, The photosensitive resin composition comprises the following components in parts by weight: 20-50 parts of the polymer resin according to any one of claims 1-5, 10-30 parts of the photopolymerizable compound, and 1-5 parts of the photopolymerization initiator; Preferably, the photosensitive resin composition further includes 0-3 parts of an additive; Preferably, the photosensitive resin composition further includes 12-69 parts of solvent; Preferably, the photopolymerizable compound includes any one or a combination of at least two of acrylamide compounds, acrylate compounds, or vinyl compounds; Preferably, the vinyl compound comprises any one or a combination of at least two of N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, or N-vinylimidazolium; Preferably, the photopolymerization initiator includes any one or a combination of at least two of the following: benzophenone initiators, triazine initiators, dialkoxyacetophenone initiators, α-hydroxyalkylphenyl ketone initiators, α-aminealkylphenyl ketone initiators, acylphosphine oxide initiators, benzophenone initiators, benzoin initiators, benzoyl initiators, heterocyclic aromatic ketone initiators, or oxime ester photoinitiators; Preferably, the additives include any one or a combination of at least two of the following: fillers, curing agents, leveling agents, adhesion promoters, antioxidants, or ultraviolet absorbers; Preferably, the photosensitive resin composition further comprises a solvent.

8. A cured film, characterized in that, The cured film is obtained by curing the photosensitive resin composition as described in claim 6 or 7.

9. A photosensitive resin laminate, characterized in that, The photosensitive resin laminate comprises a photosensitive resin layer formed from the photosensitive resin composition as described in claim 6 or 7, and a support supporting the photosensitive resin layer.

10. The use of the photosensitive resin composition according to claim 6 or 7 or the photosensitive resin laminate according to claim 9 in the manufacture of printed circuit boards, protective patterns, conductor patterns, lead frames, and semiconductor packages.

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