A graphene oxide enhanced photosensitive cover film composition

Abstract

The present invention belongs to the technical field of printed circuit board protective films, and specifically discloses a graphene oxide enhanced photosensitive cover film composition, which is formed by mixing and curing at least the following raw materials: 100 parts by weight of an alkali-soluble resin, 10-40 parts by weight of an acrylate monomer, 0.1-10 parts by weight of a photopolymerization initiator, 10-60 parts by weight of a thermal curing agent, 0.01-10 parts by weight of graphene oxide, and 0.1-10 parts by weight of a colorant. Compared with the prior art, the composition of the present invention has significantly improved flexibility, excellent mechanical properties, can use carbon black as a colorant, and has high resolution.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuit board protective films, and specifically relates to a graphene oxide enhanced photosensitive cover film composition. Background Art

[0002] In recent years, the popularity of smartphones and tablet terminals and their performance improvement are advancing rapidly. For information equipment terminals represented by them, consumers have high demands for miniaturization and thinness. In order to respond to this demand, the internal circuit substrate of the product needs to develop towards high density and minimum space. Therefore, the use of flexible printed circuit boards that can be bent and stored and can increase the freedom of circuit configuration is expanding.

[0003] In the manufacturing process of printed circuit boards, a protective film called a cover layer or solder mask is required to cover the printed circuit board in order to protect the wiring (circuit) pattern on the substrate from the external environment, or to prevent solder from adhering to non-soldering parts when soldering electronic components on the printed circuit board. For flexible printed circuit boards, the protective film must have good flexibility to meet the bending performance requirements, but most existing protective films are difficult to meet the requirements.

[0004] Patent CN103676475 discloses a black curable resin composition, including a photosensitive resin containing a carboxyl group, a photopolymerization initiator, a diluent, an epoxy compound, a polyurethane (meth) acrylate, and a perylene-based black colorant. The patent improves the flexibility of the cured product by using polyurethane (meth) acrylate and perylene-based black colorants in the curable resin composition, wherein the polyurethane (meth) acrylate can form a cross-linked structure with each other in the cured product, and the perylene-based black colorant is used to replace the commonly used carbon black colorant to eliminate the adverse effects of carbon black on the flexibility of the protective film. The patent can improve the flexibility of the protective film to a certain extent (the number of bends without cracking the protective film is more than 2 times, up to 14 times), but the improvement level is limited, and the use of perylene-based black colorants instead of carbon black will reduce the hiding power, which will limit its application. Summary of the invention

[0005] One of the purposes of the present invention is to provide a graphene oxide enhanced photosensitive cover film composition, which has significantly improved flexibility, excellent mechanical properties, can use carbon black as a colorant, has high resolution, and good nickel-gold properties.

[0006] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0007] A graphene oxide enhanced photosensitive cover film composition is formed by mixing and curing at least the following raw materials: 100 parts by weight of an alkali-soluble resin, 10-40 parts by weight of an acrylate monomer, 0.1-10 parts by weight of a photopolymerization initiator, 10-60 parts by weight of a thermal curing agent, 0.01-10 parts by weight of graphene oxide, and 0.1-10 parts by weight of a colorant. The colorant of the present invention can be selected from pigments of different colors, such as black, blue, green, and red pigments, and specific examples are as follows: black pigments, such as carbon black MA-7, carbon black N220, etc.; blue pigments, such as phthalocyanine organic pigments such as pigment blue 15:3, pigment blue 15:6, pigment blue 15:4, and pigment blue 60; green pigments, such as green organic pigments such as pigment green PG7 and pigment green PG36; red pigments, such as pyrrolopyrrole dione organic red pigments such as pigment red 254, pigment red 264, pigment red 270, and pigment red 272.

[0008] In the above-mentioned composition formula of the present invention, graphene oxide is added, and its structural formula is as follows:

[0009]

[0010] The oxygen-containing functional groups of graphene oxide (such as carboxyl, epoxy group, etc.) undergo curing and crosslinking reactions with the alkali-soluble resin, thermosetting agent, etc. in the formula to form a crosslinked network structure, which can significantly improve the mechanical properties (folding resistance, tensile strength, elongation at break) of the protective film. Moreover, when carbon black is used as a colorant, it can still ensure that the protective film has good flexibility. Graphene oxide can fully make up for the defects of carbon black. The graphene oxide used in the present invention can be laboratory-made graphene oxide, or commercially available graphene oxide, such as single-layer graphene oxide, multi-layer graphene oxide, and industrial-grade graphene oxide products. Considering the price advantage, industrial-grade graphene oxide products are preferred.

[0011] Preferably, the alkali-soluble resin is one or more of photosensitive epoxy acrylic resin, styrene acrylic resin, and photosensitive polyurethane acrylic resin. The use of these types of alkali-soluble resins can further improve the photosensitivity and developing ability of the resin composition, thereby improving the resolution of the resin composition after film formation, meeting the high-precision requirements of the circuit board.

[0012] Furthermore, the photosensitive epoxy acrylic resin is one or more of carboxylic acid modified bisphenol A epoxy resin, carboxylic acid modified bisphenol F epoxy resin, carboxylic acid modified o-cresol epoxy resin and carboxylic acid modified biphenyl epoxy resin (commercially available products of the photosensitive epoxy acrylic resin containing a carboxyl group can be ZFR-1401H, CCR-4959HW, ZCR-226 of Nippon Kayaku Co., Ltd., Z-250, Z-320 of Daicel Japan, PR-300CP, PR-400 of Showa High Polymer Co., Ltd.); the styrene acrylic resin is a carboxylic acid modified styrene acrylic resin having a weight average molecular weight of 3-20w and a glass transition temperature of 90-150°C; the photosensitive polyurethane acrylic resin is one or more of aliphatic polyurethane acrylic resin, alicyclic polyurethane acrylic resin and aromatic polyurethane acrylic resin.

[0013] Preferably, the acid value of the alkali-soluble resin is 60-150 mgKOH / g. When the acid value is lower than 60 mgKOH / g, the development is poor, resulting in problems such as residual adhesive and incomplete development; and when the acid value is higher than 150 mgKOH / g, the development is excessive, resulting in line width and line spacing deviating from the standard value.

[0014] Preferably, the molecular weight of the acrylic ester monomer is 200-2000, and the glass transition temperature is -30-100°C. In terms of specific variety selection, the acrylate monomers include but are not limited to (ethoxy)phenol (meth)acrylate, stearic acid acrylate, ethoxy (propoxy) nonylphenol (meth)acrylate, ethoxy (propoxy) tetrahydrofurfuryl (meth)acrylate, 1,6-hexanediol diacrylate, PPG (400) diacrylate, tricyclohexanedimethanol diacrylate, dioxanediol diacrylate, ethoxylated (propoxylated) bisphenol A di(meth)acrylate, polyethylene glycol (400) diacrylate, polypropylene glycol (600) diacrylate, ethoxy (propoxy) trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

[0015] Preferably, the photopolymerization initiator is an acylphosphine oxide photopolymerization initiator and / or an oxime ester photopolymerization initiator. The photopolymerization initiator of the present invention includes but is not limited to 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one, 2,4-diethylthioxanthone, acylphosphine oxide photopolymerization initiator, oxime ester photopolymerization initiator (such as 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3-yl]-, 1,8- One or more of bis(O-acetyl oxime)); wherein, acylphosphine oxide photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, etc., oxime ester photopolymerization initiators such as 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3-yl]-, 1,8-bis(O-acetyl oxime), etc. The preferred category of photopolymerization initiators is acylphosphine oxide photopolymerization initiators and / or oxime ester photopolymerization initiators, because they have better effects of improving the photocuring performance of the resin composition and increasing the photosensitivity.

[0016] Preferably, the heat curing agent is an epoxy resin with an epoxy equivalent of 70-500 g / eq and at least two epoxy groups, which can effectively improve the soldering heat resistance, developability and adhesion of the cured film. The epoxy resin includes but is not limited to one or more of bisphenol epoxy resin (including bisphenol A type, bisphenol F type, bisphenol S type, etc.), biphenyl epoxy resin, novolac epoxy resin (including phenol novolac type, novolac type, etc.), epoxy resin containing naphthalene ring, alicyclic epoxy resin, and aliphatic epoxy resin.

[0017] Furthermore, the heat curing agent is a compound of bisphenol epoxy resin and aliphatic epoxy resin. The commercially available aliphatic epoxy resin includes TTA186, TTA184, TTA182, TTA27, TTA21P and the like.

[0018] Preferably, the raw materials further include 0-10 parts by weight of a toughening agent. The addition of a toughening agent can further improve the bendability of the protective film formed by the composition, and make the protective film perform better in terms of heat resistance, rebound force, etc. The toughening agent includes but is not limited to one or more of core-shell rubber toughened epoxy resin, thermoplastic elastomer, polyurethane elastomer, and rubber powder. Among them: commercially available core-shell rubber toughened epoxy resins include Kaneka's MX154, MX113, MX158, M257, etc.; thermoplastic elastomers include styrene-butadiene block copolymers (SBS), styrene-poly(ethylene-ethylene / propylene) block-polystyrene (SEEPS), styrene-isoprene-styrene block copolymers (SIS), etc.; commercially available polyurethane elastomers include Dainichiseika's RHC-730, Negami Chemical Industry's Artpearl C-300T, Artpearl C-400T, Artpearl C-600T, Artpearl SE-050T, Artpearl GR-50W, etc.; commercially available rubber powders include Kaneka's MZ100, MZ 210, MZ711, etc.

[0019] Preferably, the raw materials also include 0-2 parts by weight of a thermal curing accelerator to further improve the thermal curing performance, reduce the thermal curing temperature, and shorten the thermal curing time; from the perspective of extending the storage period and improving the storage performance at room temperature, the thermal curing accelerator is preferably a latent thermal curing accelerator.

[0020] Furthermore, the thermal curing accelerator is one or more of boron trifluoride ethylamine complex, adipic acid dihydrazide, p-hydroxybenzoic acid hydrazide, isophthalic acid hydrazide, diaminodiphenyl sulfone, dicyandiamide and derivatives thereof.

[0021] Preferably, in order to improve hiding power, the raw material further comprises 1-10 parts by weight of a light diffuser, and the light diffuser is an organic light diffuser or / and an inorganic light diffuser. Organic light diffusers include silicone powders, acrylic resin powders, etc., and inorganic light diffusers include silica matting powders, etc. More specifically, commercially available silicone powders may be selected from EP-2600, EP-2601, EP-5500, EP-606, etc. of Toray-Dow Corning Co., Ltd.; acrylic resin powders may be selected from Kane ACE®MP-90, Kane ACE®MP-91 of Kane Kagawa Chemical Co., Ltd., MBX-40, MBX-50 of Sekisui Chemical Co., Ltd., etc.; inorganic light diffusers may be selected from BASF LT-1622, Haoyang OMATT-2018N, OMATT-2015N, etc.

[0022] Preferably, in order to further improve the stability, wetting and dispersibility, and film-forming property of the resin composition, the raw material further comprises 0.01-1 parts by weight of an auxiliary agent, wherein the auxiliary agent is one or more of a dispersant, a leveling agent, a defoaming agent, and an adhesion promoter. Wherein: the dispersant may use a known dispersant, such as a polyester propionate dispersant, a silicone resin dispersant, a fluorine surfactant dispersant, and commercially available products may include BYK9077, BYK110, BYK168, SDA-2, SDA-3, HLD-6, etc.; the leveling agent may use a known leveling agent, such as a polyester acrylate leveling agent, a silicone resin leveling agent, etc., and commercially available products may include BYK394, BYK322, BYK UV3530, Efka FL 3740, Modarez PW 336, etc.; the defoamer may use a known defoamer, such as polysiloxanes, polyolefins, polyethers, polyacrylates, and commercially available products may include BYK015, BYK1730, BYK354, GPE-3000, Defom 5300, Defom6800, etc.; commercially available adhesion promoters include ADP-S481, ADP-S478, ADP-S479, Kayamer PM-2, Kayamer PM-21, etc.

[0023] Preferably, in order to adjust the rheological properties and physical and mechanical properties of the glue, improve the wear resistance and durability of the coating, and reduce the dimensional shrinkage, the raw materials also include 0-40 parts by weight of inorganic fillers. The inorganic fillers are selected from physical fillers such as silicon dioxide, barium sulfate, calcium sulfate, aluminum hydroxide, and talc.

[0024] The second object of the present invention is to provide the application of the above-mentioned graphene oxide enhanced photosensitive cover film composition as an insulating protective film for printed circuit boards. The specific application method is as follows: the above-mentioned resin composition is roll-coated on a PET substrate to form a wet film, and then baked in a hot air blast drying oven at 70-90°C for 15 to 30 minutes for pre-drying; after sufficient drying, the pre-baked film has good dryness to the touch, and then the pre-baked film is applied to a flexible printed circuit board by hot roller lamination or vacuum lamination. Then, a film negative is placed on the surface of the pre-dried resin composition or the surface of PET, and ultraviolet rays are irradiated from above. The ultraviolet rays reach the resin composition through the light-transmitting part of the film to achieve exposure, and the part covered by the film cannot be exposed. The exposure energy is 100-500 mJ.cm -2； Then, a 0.8~1.2wt% Na2CO3 dilute alkali aqueous solution is used to remove the non-exposed area and develop the coating film. The development time is 30~60s, the development temperature is 27~33℃, and the spray pressure is 0.2~0.4MPa. Finally, a hot air blast drying oven is used to heat cure at 150~180℃ for 1~1.5h, thereby forming a film that can be used on a flexible printed circuit board.

[0025] The present invention has the following beneficial effects:

[0026] 1. The present invention adds graphene oxide filler, and utilizes the oxygen-containing functional groups of graphene oxide itself to undergo a curing and cross-linking reaction with the resin raw materials in the formula to form a cross-linked network structure, which significantly improves the mechanical properties such as folding resistance, tensile strength, and elongation at break, and can compensate for the adverse effects of carbon black on the flexibility of the protective film, so that the protective film still has good flexibility when carbon black is used as a colorant; more optimally, the present invention further improves the folding resistance of the protective film by adding a toughening agent, and the insulating protective film formed by the composition of the present invention can be bent up to 20 times without breaking.

[0027] 2. When carbon black is used as a colorant, it is difficult for light to reach the deep layer of the protective film, resulting in insufficient light curing of the deep part of the protective film, large side etching after development, poor adhesion, and further affecting the resolution and nickel-gold properties. The present invention effectively solves this problem by adding graphene oxide filler. On the one hand, graphene oxide has excellent light transmittance, which provides the basic conditions for light to reach the deep layer of the protective film; on the other hand, graphene oxide is a lamellar structure with a high specific surface energy and good hydrophilicity, and has good dispersibility in water and polar organic solvents. The interpenetration of graphene and carbon black effectively inhibits the aggregation of the two fillers themselves, and obtains a highly dispersed, highly exfoliated composite material dispersed in nanometer scale, which reduces the influence of carbon black and enables graphene oxide to give full play to its light transmittance. Therefore, the present invention can ensure that the protective film has high resolution and good nickel-gold properties.

[0028] 3. In addition to carbon black, the present invention can also use other colorants (such as blue, red, and green organic pigments). The protective film prepared also has good mechanical properties, resolution, and nickel-gold properties, and can meet various appearance and application requirements.

[0029] 4. The lamellar structure and good self-recovery ability of graphene oxide also give the protective film good gas barrier properties and self-healing ability, which can increase the service life of the protective film and has advantages that traditional fillers cannot match. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : Table of main components of raw material formula of each embodiment and comparative example composition of the present invention.

[0031] Figure 2 : Performance test data table of various embodiments and comparative example compositions of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.01g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0035] Example 2

[0036] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mg KOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mg KOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.05g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0037] Example 3

[0038] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.1g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0039] Example 4

[0040] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304 and 0.2g TPO, 0.05g DETX), 4g thermal curing agent (including 2.5g BNE-200 epoxy resin and 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.2g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are firstly ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain the glue solution, which is stored in the dark for later use.

[0041] Example 5

[0042] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.5g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0043] Example 6

[0044] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 1g industrial grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0045] Example 7

[0046] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g green K8730 organic dye, 0.1g industrial-grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0047] Example 8

[0048] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g blue 15:4 organic dye, 0.1g industrial-grade graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0049] Example 9

[0050] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin and 1.5g TTA21P epoxy resin), 0.01g of boron trifluoride ethylamine latent curing accelerator, 0.2g of carbon black MA-7, 0.5 g single-layer graphene oxide, 2.0 g light diffuser EP-2601, 0.6 g other additives (including 0.3 g dispersant BYK168, 0.1 g leveling agent BYK 394, 0.1 g defoamer BYK354, 0.1 g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are firstly ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0051] Example 10

[0052] A graphene oxide enhanced photosensitive cover film composition is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin, 1.5g TTA21P epoxy resin), 0.01g boron trifluoride ethylamine latent curing accelerator, 0.2g carbon black MA-7, 0.5g multilayer graphene oxide, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the graphene oxide enhanced photosensitive cover film composition, the above raw materials are first ground by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain a glue solution, which is stored in the dark for later use.

[0053] Comparative Example 1

[0054] The present comparative example provides a curable resin composition, which is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin and 1.5g TTA21P epoxy resin), 0.01g of boron trifluoride ethylamine latent curing accelerator, 0.2g of carbon black MA-7, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the curable resin combination, the above raw materials are firstly grinded by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain the glue solution, which is stored in the dark for later use.

[0055] Comparative Example 2

[0056] The present comparative example provides a curable resin composition, which is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin and 1.5g TTA21P epoxy resin), 0.01g of boron trifluoride ethylamine latent curing accelerator, 0.2g of green K8730 organic pigment, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the curable resin combination, the above raw materials are firstly grinded by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain the glue solution, which is stored in the dark for later use.

[0057] Comparative Example 3

[0058] The present comparative example provides a curable resin composition, which is prepared by mixing and curing the following raw materials: 20g of alkali-soluble photosensitive epoxy acrylic resin GE8988C (acid value 90mgKOH / g, solid content 60%), 5g of alkali-soluble photosensitive epoxy acrylic resin ZAR-1035 (acid value 100mgKOH / g, solid content 64%), 4g of acrylate monomer (including 2.0g 9EOTMPTA and 2.0g BP(EO)10DA), 0.3g of photopolymerization initiator (including 0.05g TR-PBG-304, 0.2g TPO and 0.05g DETX), 4g of thermal curing agent (including 2.5g BNE-200 epoxy resin and 1.5g TTA21P epoxy resin), 0.01g of boron trifluoride ethylamine latent curing accelerator, 0.2g of blue 15:4 organic dye, 2.0g light diffuser EP-2601, 0.6g other additives (including 0.3g dispersant BYK168, 0.1g leveling agent BYK 394, 0.1g defoamer BYK354, 0.1g adhesion promoter ADP-S478). When preparing the curable resin combination, the above raw materials are firstly grinded by three rollers, then dissolved and dispersed by high-speed stirring, and finally filtered to obtain the glue solution, which is stored in the dark for later use.

[0059] The main ingredients of the raw material formula of Examples 1-10 and Comparative Examples 1-3 are shown in the table below: Figure 1As shown, the performance tests were performed on the compositions of Examples 1-10 and Comparative Examples 1-3, and the test items and test methods were as follows:

[0060] 1. Resolution

[0061] The film RP-4: um, L / S = n / 400 was used to evaluate the resolution. After development, it was observed using a scanning electron microscope (SEM). The minimum line width with good side morphology and complete development was used as the evaluation standard.

[0062] 2. Bending resistance of cured film

[0063] The cured films with a thickness of 25 μm prepared in the examples and comparative examples were subjected to a 180° folding test (R=0 mm) and a load of 1 kg was applied, and then the films were restored to a flat state. Furthermore, the folded portion was folded 180° with the substrate on the inside and a load of 1 kg was applied. The films were observed using an optical microscope at x200, and the number of cracks that began to appear was recorded and evaluated according to the following criteria:

[0064] ◎: No cracks on the cured film after folding 20 times; ○: Slight cracks on the cured film after folding 10 times;

[0065] △: After folding in half for 6 times, the cured film had slight cracks; ×: After folding in half for 2 times, the cured film cracked.

[0066] 3. Nickel-Au

[0067] The cured films with a thickness of 25 μm prepared in the examples and comparative examples were immersed in nickel-gold solution for 1 hour to achieve a nickel-plated layer thickness of 5 μm and a gold layer thickness of 0.1 μm. Then, a hundred grids were scratched on the surface of the cured film, and a peeling test was performed with 3M tape to observe whether the cured film would fall off and evaluate it according to the following criteria:

[0068] ◎: The cured film did not fall off; ○: The cured film did not fall off, only the edge cut by the blade fell off;

[0069] △: The cured film partially falls off, and the number of small cells that fall off is ≤5; ×: The cured film falls off completely.

[0070] 4. Tensile strength

[0071] The cured films prepared in the examples and comparative examples were subjected to tensile elongation at break test: the test was performed using a tensile tester (Shimadzu EZ-SX) at a tensile speed of 1.0 mm / min and 25°C according to JIS K7127, and the evaluation was performed according to the following criteria:

[0072] ◎: greater than 100 MPa; △: between 10-100 MPa; ×: less than 10 MPa.

[0073] 5. Elongation at break

[0074] Test methods such as tensile strength tests are evaluated based on the following criteria:

[0075] ◎: greater than 5%; △: between 1%-5%; ×: less than 1%.

[0076] 6. Young's modulus

[0077] Test methods such as tensile strength tests are evaluated based on the following criteria:

[0078] ◎: greater than 10 GPa; △: between 1-10 GPa; ×: less than 1 GPa.

[0079] The above performance test results are as follows Figure 2 As shown by Figure 2 It can be seen that the addition of graphene oxide can significantly improve the mechanical properties, folding resistance and nickel-gold resistance of the protective film.

[0080] This specific implementation is only an explanation of the present invention, not a limitation of the present invention. Any changes made by those skilled in the art after reading the specification of the present invention will be protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A graphene oxide enhanced photosensitive cover film composition, characterized in that: The composition is formed by mixing and curing at least the following raw materials: 100 parts by weight of an alkali-soluble resin, 10-40 parts by weight of an acrylate monomer, 0.1-10 parts by weight of a photopolymerization initiator, 10-60 parts by weight of a thermal curing agent, 0.01-10 parts by weight of graphene oxide, and 0.1-10 parts by weight of a colorant; the alkali-soluble resin is one or more of a photosensitive epoxy acrylic resin, a styrene acrylic resin, and a photosensitive polyurethane acrylic resin.

2. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The acid value of the alkali-soluble resin is 60-150 mgKOH / g.

3. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The molecular weight of the acrylic ester monomer is 200-2000, and the glass transition temperature is -30-100°C.

4. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The photopolymerization initiator is an acylphosphine oxide photopolymerization initiator and / or an oxime ester photopolymerization initiator.

5. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The thermal curing agent is an epoxy resin with an epoxy equivalent of 70-500 g / eq and containing at least two epoxy groups.

6. The graphene oxide enhanced photosensitive cover film composition according to claim 5, characterized in that: The thermal curing agent is a compound of bisphenol epoxy resin and aliphatic epoxy resin.

7. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The raw materials further include 0-2 parts by weight of a thermal curing accelerator, and the thermal curing accelerator is a latent thermal curing accelerator.

8. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The raw materials further include 1-10 parts by weight of a light diffuser, and the light diffuser is an organic light diffuser and / or an inorganic light diffuser.

9. The graphene oxide enhanced photosensitive cover film composition according to claim 1, characterized in that: The raw materials also include 0.01-1 parts by weight of an auxiliary agent, wherein the auxiliary agent is one or more of a dispersant, a leveling agent, a defoaming agent, and an adhesion promoter.

10. Use of the graphene oxide enhanced photosensitive cover film composition according to any one of claims 1 to 9 as an insulating protective film for a flexible printed circuit board.

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