A photosensitive conductive resin composition and use thereof

Abstract

This invention provides a photosensitive conductive resin composition and its application. The photosensitive conductive resin composition comprises, by weight, the following components: 20-60 parts of a photosensitive polymer, 10-20 parts of an epoxy resin, 5-20 parts of an acrylate monomer, 0.5-5 parts of a photoinitiator, 20-60 parts of a conductive carbon filler, and 1-10 parts of an additive; the volume resistivity of the conductive carbon filler is ≤0.5 Ω·m. Through the screening and synergistic compounding of specific components, the photosensitive conductive film prepared from this resin composition exhibits excellent conductivity and peel strength, high photosensitivity resolution, and excellent developability, thus meeting the application requirements of photosensitive conductive films.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit board technology and relates to a photosensitive conductive resin composition and its application. Background Technology

[0002] As electronic information products increasingly trend towards thinner, lighter, smaller, and more multifunctional designs, printed circuit boards (PCBs), which are the main support for electronic components, are also undergoing continuous technological advancements to provide high-density wiring, thinness, micro-apertures, and multi-dimensional design. The substrate material largely determines the performance of the PCB, thus necessitating the development of next-generation substrate materials.

[0003] Unreinforced films or resin-coated copper foils are being developed and applied as next-generation substrate materials due to their ability to achieve thinner profiles, high-density wiring, micro-pores, and multi-dimensional molding. Traditional conductive films primarily use laser drilling to create interconnecting holes, while photosensitive films can achieve photo-induced holes, which is not only more efficient than laser drilling but also allows for smaller pore sizes, enabling applications in higher-end fine-line circuitry.

[0004] To meet specific sheet resistance requirements, conductive fillers are typically added to photosensitive conductive adhesive films to improve their conductivity. However, the introduction of conductive fillers negatively impacts properties such as peel strength.

[0005] In summary, how to improve the peel strength and photosensitive resolution of photosensitive conductive adhesive films without reducing other properties is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a photosensitive conductive resin composition and its application. Through the screening and synergistic compounding of specific components, the photosensitive conductive film prepared from this resin composition has excellent conductivity and peel strength, high photosensitive resolution and excellent easy development characteristics.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a photosensitive conductive resin composition, wherein the photosensitive conductive resin composition comprises, by weight parts, the following components:

[0009]

[0010] The volume resistivity of the conductive carbon filler is ≤0.5Ω·m, for example, it can be 0.5Ω·m, 0.4Ω·m, 0.3Ω·m, 0.2Ω·m, 0.1Ω·m, 0.08Ω·m, 0.05Ω·m, 0.02Ω·m or 0.01Ω·m, etc.

[0011] In this invention, the volume resistivity of conductive carbon fillers is tested using the voltammetric method. A voltage is applied across the filler and the current flowing through it is measured. Then, the resistance value and resistivity are calculated sequentially.

[0012] The photosensitive conductive resin composition provided by this invention comprises a combination of a photosensitive polymer, an epoxy resin, an acrylate monomer, a photoinitiator, a conductive carbon filler, and additives. Through the screening and synergistic compounding of specific components, the photosensitive conductive film prepared from this resin composition has excellent conductivity and peel strength, high photosensitivity resolution, and excellent developability, which can meet the application requirements of photosensitive conductive films.

[0013] It is worth noting that by introducing conductive carbon fillers with specific volume resistivity, the photosensitive conductive film can be ensured to have excellent peel strength while maintaining a suitable sheet resistance, thus exhibiting excellent conductivity. Since photosensitive resin is an insulating resin, its conductivity is achieved by adding conductive carbon fillers. The higher the resistivity, the higher the proportion of conductive carbon filler needed to achieve a specific sheet resistance; conversely, the more conductive carbon filler added, the lower the proportion of photosensitive resin, and the lower the peel strength.

[0014] In this invention, the content of the photosensitive polymer in the photosensitive conductive resin composition is 20-60 parts, for example, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts; the content of the epoxy resin in the photosensitive conductive resin composition is 10-20 parts, for example, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts; the content of the acrylate monomer in the photosensitive conductive resin composition is 5-20 parts, for example, 5 parts, 7 parts, 9 parts, 10 parts, or 12 parts. The photoinitiator content in the photosensitive conductive resin composition is 0.5-5 parts, for example, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, or 5 parts; the conductive carbon filler content in the photosensitive conductive resin composition is 20-60 parts, for example, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts; the auxiliary agent content in the photosensitive conductive resin composition is 1-10 parts, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts.

[0015] Preferably, the photosensitive polymer comprises an epoxy resin containing unsaturated double bonds and carboxyl groups.

[0016] In this invention, the photosensitive polymer can be commercially available or prepared by the following method: the photosensitive polymer is prepared by reacting epoxy resin with acrylic monomer and then reacting with acid anhydride.

[0017] Preferably, the epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, phosphorus-containing epoxy resin, MDI-modified epoxy resin, phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, or alicyclic epoxy resin.

[0018] Preferably, the acrylate monomer comprises at least a bifunctional acrylate.

[0019] In this invention, the at least bifunctional acrylate includes any one or a combination of at least two of the following: 1,6-hexanediol diacrylate, dipentaerythritol pent- / hex-acrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, or pentaerythritol tetraacrylate.

[0020] Preferably, the photoinitiator includes any one or a combination of at least two of the following: alkyl phenyl ketone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanoceramic photopolymerization initiators, or oxime ester photopolymerization initiators.

[0021] As the photoinitiator component used in this invention, there are no particular limitations as long as it can polymerize the photosensitive polymer component, and it can be appropriately selected from commonly used photopolymerization initiators. For example, conventionally known photopolymerization initiators such as alkyl phenyl ketone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanoceramsite-based photopolymerization initiators, and oxime ester-based photopolymerization initiators can be used alone or in combination.

[0022] Examples of alkyl phenyl ketone photopolymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2,2-dimethoxy-1,2-diphenylethane-1-one, and benzyl dimethyl ketal photopolymerization initiators; 1-hydroxy-cyclohexyl-phenyl-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4- α-hydroxyalkyl phenyl ketone photoinitiators such as (2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1-one; α-aminoacetyl ketone photoinitiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinoacetone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, and N,N-dimethylaminoacetylphenyl, can be used alone or in combination.

[0023] As an acylphosphine oxide-based photopolymerization initiator, there are no particular limitations on the type of compound that has an acylphosphine oxide group (=P(=O)-C(=O)- group). Examples include (2,6-dimethoxybenzoyl)-2,4,4-pentylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoyl phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,5-dihydroxyphenyl)diphenylphosphine oxide, (p-hydroxyphenyl)diphenylphosphine oxide, bis(p-hydroxyphenyl)phenylphosphine oxide, and tri(p-hydroxyphenyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, etc. One type can be used alone or multiple types can be used in combination.

[0024] Examples of titanium-based photopolymerization initiators include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium, which can be used alone or in combination.

[0025] Examples of oxime ester-based photopolymerization initiators include ethyl ketone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, and 1-(O-acetyl oxime).

[0026] In this invention, the photoinitiator may be photoinitiator TPO, photoinitiator 379, photoinitiator 907, photoinitiator 819, photoinitiator TMO, photoinitiator EDB, or photoinitiator 369, etc.

[0027] Preferably, the conductive carbon filler includes any one or a combination of at least two of single-walled carbon nanotubes, conductive carbon black, or graphene.

[0028] In this invention, the conductive carbon filler can be used directly or surface-treated with a surface treatment agent. The surface treatment agent includes any one or a combination of at least two of silane coupling agents, organosilicon oligomers, or titanate coupling agents. Those skilled in the art can select the appropriate agent based on experience and process requirements.

[0029] Preferably, the average particle size of the conductive carbon filler is 0.1-5 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm.

[0030] In this invention, the average particle size of the conductive carbon filler was obtained by measuring the particle size using a Malvern laser particle size analyzer.

[0031] It is worth noting that the average particle size of the conductive carbon filler needs to be controlled within the range of 0.1-5 μm. This imparts excellent conductivity and peel strength to the photosensitive conductive resin composition, photosensitive conductive film, and metal foil laminate, while also ensuring easy dispersion and good uniformity of the adhesive solution. If the average particle size of the filler is too small, it will be difficult to disperse in the resin system, resulting in significant agglomeration; if the average particle size of the filler is too large, it will reduce the resolution of the photosensitive conductive resin.

[0032] Preferably, the additives include any one or a combination of at least two of polyalkylammonium salts, polyesters, polyvinylpyrrolidone, or silicone oils.

[0033] In this invention, the polyalkylammonium salt is an alkylammonium salt of a high molecular weight copolymer.

[0034] In this invention, by introducing additives into the resin system, not only can the viscosity of conductive carbon fillers be reduced, but the filling amount of conductive carbon fillers in the system can also be increased to meet the application requirements of photosensitive conductive adhesive films.

[0035] It should be noted that solvents can also be added to the above-mentioned photosensitive conductive resin composition. The specific amount of solvent added should be selected by those skilled in the art based on experience and process requirements, so as to achieve a suitable viscosity for the resin composition to facilitate coating, etc. During subsequent drying, semi-curing, or complete curing processes, the solvent in the resin composition will partially or completely evaporate.

[0036] In this invention, the solvents used are not specifically limited. Alcohols such as methanol, ethanol, and butanol; ethers such as ethyl cellosolve, butyl cellosolve, ethylene glycol-methyl ether, carbitol, and butyl carbitol; ketones such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and mesitylene; esters such as ethoxyethyl acetate and ethyl acetate; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. One of the above solvents can be used alone, or two or more can be mixed. Preferably, aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene are mixed with ketone fluxes such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

[0037] The photosensitive conductive resin composition provided by the present invention can be prepared by the following method, the preparation method comprising: mixing and dispersing each component in the photosensitive conductive resin composition evenly to obtain the photosensitive conductive resin composition.

[0038] In a second aspect, the present invention provides a photosensitive conductive adhesive film, wherein the material of the photosensitive conductive adhesive film comprises the photosensitive conductive resin composition as described in the first aspect.

[0039] Preferably, the photosensitive conductive adhesive film is prepared by coating the photosensitive conductive resin composition onto a release material and then drying and / or semi-curing it.

[0040] In this invention, the thickness of the photosensitive conductive adhesive film is 5-300 μm, for example, it can be 5 μm, 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm or 300 μm, more preferably 10-200 μm, and even more preferably 20-100 μm.

[0041] Preferably, the photosensitive conductive adhesive film is further provided with a protective film on the side away from the release material.

[0042] Thirdly, the present invention provides a metal foil laminate, the metal foil laminate comprising at least one photosensitive conductive film as described in the second aspect and metal foil located on one or both sides of the laminated photosensitive conductive film.

[0043] In this invention, when a metal foil is provided on one side of the metal foil laminate, a protective film covered on the photosensitive conductive adhesive film is provided on the other side.

[0044] In this invention, the metal foil is a copper foil.

[0045] In this invention, the total thickness of the photosensitive conductive adhesive film in the metal foil laminate is 5-300 μm, for example, it can be 5 μm, 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm or 300 μm, etc., more preferably 10-200 μm, and even more preferably 20-100 μm.

[0046] In this invention, the thickness of the metal foil in the metal foil laminate is 1-105 μm, for example, it can be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or 105 μm, more preferably 3-35 μm, and even more preferably 5-18 μm.

[0047] Fourthly, the present invention provides a multilayer printed circuit board, the multilayer printed circuit board comprising at least one photosensitive conductive film as described in the second aspect and a circuit substrate located on one or both sides of the multilayered photosensitive conductive film, or a circuit substrate located on one side of the multilayered photosensitive conductive film and a metal foil located on the other side.

[0048] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The photosensitive conductive resin composition provided by the present invention comprises a combination of photosensitive polymer, epoxy resin, acrylate monomer, photoinitiator, conductive carbon filler and additives. Through the screening and synergistic compounding of specific components, the photosensitive conductive film prepared from the resin composition has excellent conductivity and peel strength, high photosensitive resolution and excellent easy development characteristics; wherein, the peel strength is 4.3-6.5 N / cm, the sheet resistance is 30-150 Ω, and under preferred conditions the peel strength is 5.0-6.5 N / cm, and the sheet resistance is 30-90 Ω;

[0051] (2) The photosensitive conductive resin composition provided by the present invention further ensures that the photosensitive conductive film has excellent peel strength while its sheet resistance is within a suitable range by controlling the volume resistivity and content of conductive carbon filler, thereby having excellent conductivity. Detailed Implementation

[0052] 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 in any way.

[0053] All materials used in the specific embodiments of this invention can be purchased commercially or prepared using conventional methods in the prior art. Unless otherwise specified, the materials used in this invention are as follows:

[0054] Acrylic acid monomer: Dow Chemical Company, USA;

[0055] Dimethylbenzylamine: Hubei Chengfeng Chemical Co., Ltd.;

[0056] Tetrahydrophthalic anhydride: Wuhan Prof Biotechnology Co., Ltd.;

[0057] Methacrylic acid monomer: Dow Chemical Company, USA.

[0058] Preparation Example 1

[0059] This preparation example provides a method for preparing a photosensitive polymer, the preparation method comprising:

[0060] 100 parts of phenolic epoxy resin EPR627, 30 parts of acrylic monomer and 0.5 parts of dimethylbenzylamine were mixed and heated at 100°C for 6 hours. Then the mixture was cooled to 80°C, and 50 parts of tetrahydrophthalic anhydride were added. The mixture was reacted for 6 hours and then cooled to room temperature to obtain a photosensitive polymer containing unsaturated bonds and carboxyl groups.

[0061] Preparation Example 2

[0062] 100 parts of biphenyl epoxy resin NC3000H, 40 parts of methacrylic acid monomer and 0.5 parts of dimethyl benzylamine were mixed and heated at 100°C for 6 hours. Then the mixture was cooled to 80°C, and 50 parts of tetrahydrophthalic anhydride were added. The mixture was reacted for 6 hours and then cooled to room temperature to obtain a photosensitive polymer containing unsaturated bonds and carboxyl groups.

[0063] Photosensitive polymer 1: provided by preparation example 1;

[0064] Photosensitive polymer 2: provided by preparation example 2;

[0065] Epoxy Resin 1: Phenolic epoxy resin, HEXION, EPR627;

[0066] Epoxy Resin 2: Biphenyl type epoxy resin, Nippon Kayaku, NC3000H;

[0067] Epoxy Resin 3: Naphthalene-containing epoxy resin, DIC, HP4710;

[0068] Acrylate monomer 1:1,6-hexanediol diacrylate (HDDA), Zhongshan Dixin Chemical Co., Ltd.;

[0069] Acrylate monomer 2: Dipentaerythritol pentyl / hexyl acrylate, Zhongshan Dixin Chemical Co., Ltd.;

[0070] Photoinitiator 1: Photoinitiator TPO-L, Jiangsu Juming Chemical Technology Co., Ltd.;

[0071] Photoinitiator 2: Photoinitiator 379, Qingdao Zhenguang Functional Materials Technology Co., Ltd.;

[0072] Conductive carbon filler 1: Conductive carbon black, Tianjin Yiborui Chemical Co., Ltd., model F200A, with an average particle size of 0.1μm and a volume resistivity of 0.5Ω·m;

[0073] Conductive carbon filler 2: Single-walled carbon nanotubes, Carbon Peak Technology, model TF220, with an average particle size of 5μm and a volume resistivity of 0.1Ω·m;

[0074] Conductive carbon filler 3: Graphene, Jiangsu Xianfeng Nano, model XFQ024, with an average particle size of 0.1μm and a volume resistivity of 0.01Ω·m;

[0075] Conductive carbon filler 4: Conductive carbon black, Tianjin Yiborui Chemical Co., Ltd., model F900A, with an average particle size of 0.05μm and a volume resistivity of 0.5Ω·m;

[0076] Conductive carbon filler 5: Conductive carbon black, Tianjin Yiborui Chemical Co., Ltd., model F10A, with an average particle size of 8μm and a volume resistivity of 0.5Ω·m;

[0077] Conductive carbon filler 6: Conductive carbon black, DENKA, model LI100, with an average particle size of 0.3μm and a volume resistivity of 0.8Ω·m;

[0078] Additive 1: Polyalkylammonium salt, BYK, model BYK-9076;

[0079] Additive 2: Polyalkylammonium salt, BYK, model BYK-2152.

[0080] Example 1

[0081] This embodiment provides a photosensitive conductive resin composition, which comprises the following components by weight: 30 parts photosensitive polymer 1, 10 parts phenolic epoxy resin EPR627, 15 parts HDDA, 5 parts photoinitiator TPO-L, 40 parts conductive carbon filler 1, and 4 parts BYK-9076.

[0082] Example 2

[0083] This embodiment provides a photosensitive conductive resin composition, which comprises the following components by weight: 60 parts photosensitive polymer 1, 14 parts biphenyl epoxy resin NC3000H, 5 parts dipentaerythritol pent- / hexyl acrylate, 1 part photoinitiator 379, 20 parts conductive carbon filler 2, and 1 part BYK-9076.

[0084] Example 3

[0085] This embodiment provides a photosensitive conductive resin composition, which comprises the following components by weight: 30 parts photosensitive polymer 1, 10 parts naphthalene-containing epoxy resin HP4710, 18 parts HDDA, 2 parts photoinitiator 379, 40 parts conductive carbon filler 3, and 5 parts BYK-9076.

[0086] Example 4

[0087] This embodiment provides a photosensitive conductive resin composition, which comprises the following components by weight: 20 parts photosensitive polymer 2, 10 parts biphenyl epoxy resin NC3000H, 9.5 parts dipentaerythritol pentyl / hexyl acrylate, 0.5 parts photoinitiator 379, 60 parts conductive carbon filler 1, and 10 parts BYK-9076.

[0088] Example 5

[0089] This embodiment provides a photosensitive conductive resin composition, which comprises the following components by weight: 30 parts photosensitive polymer 1, 10 parts phenolic epoxy resin EPR627, 15 parts HDDA, 5 parts photoinitiator TPO-L, 40 parts conductive carbon filler 1, and 6 parts BYK-2152.

[0090] Example 6

[0091] This embodiment provides a photosensitive conductive resin composition, except that the conductive carbon filler 1 is replaced with an equal amount of conductive carbon filler 4, and all other conditions are the same as in Example 1.

[0092] Example 7

[0093] This embodiment provides a photosensitive conductive resin composition, except that the conductive carbon filler 1 is replaced with an equal amount of conductive carbon filler 5, and all other conditions are the same as in Example 1.

[0094] Comparative Example 1

[0095] This comparative example provides a photosensitive conductive resin composition, which comprises the following components by weight: 30 parts photosensitive polymer 1, 10 parts phenolic epoxy resin EPR627, 15 parts HDDA, 5 parts photoinitiator TPO-L, 40 parts conductive carbon filler 6, and 4 parts BYK-9076.

[0096] Comparative Example 2

[0097] This comparative example provides a photosensitive conductive resin composition, except that 15 parts of conductive carbon filler 2 are used instead of 20 parts of conductive carbon filler 2, and all other conditions are the same as in Example 2.

[0098] Comparative Example 3

[0099] This comparative example provides a photosensitive conductive resin composition, which comprises the following components by weight: 30 parts photosensitive polymer 1, 10 parts phenolic epoxy resin EPR627, 15 parts HDDA, 5 parts photoinitiator TPO-L, 140 parts conductive carbon filler 1, and 20 parts BYK-9076.

[0100] Comparative Example 4

[0101] This comparative example provides a photosensitive conductive resin composition, which comprises the following components by weight: 20 parts photosensitive polymer 2, 10 parts biphenyl epoxy resin NC3000H, 9.5 parts dipentaerythritol pentyl / hexyl acrylate, 0.5 parts photoinitiator 379, and 60 parts conductive carbon filler 1.

[0102] The photosensitive conductive resin compositions provided in the above embodiments and comparative examples were used to prepare multilayer printed circuit boards and to evaluate the samples. The peel strength and sheet resistance were tested, and the specific test results are shown in Table 1.

[0103] The methods for fabricating multilayer printed circuit boards include:

[0104] Mix an appropriate amount of butanone with the photosensitive conductive resin composition provided in the above examples or comparative examples, and stir for 2 hours to form a solution with a solid content of 65%.

[0105] The above solution is coated onto the release film, dried, and then baked in an oven at 120°C for 5 minutes to obtain a semi-cured photosensitive conductive film. The semi-cured photosensitive conductive film (40μm thick) is then pressed and cured with the browned PCB board. The release film is then removed, and surface treatment is performed, including copper plating, to form a multilayer printed circuit board with circuitry.

[0106] The photosensitive conductive adhesive film and the multilayer printed circuit board prepared from the photosensitive conductive resin composition provided in the above embodiments and comparative examples were subjected to performance testing. The specific methods are as follows:

[0107] Peel strength: The peel strength of the copper foil layer of the surface copper plating on the multilayer printed circuit board was tested using the IPC-TM-650 2.4.9 method.

[0108] A photosensitive conductive resin composition was screen-printed onto a 1.6 mm thick FR-4 substrate (copper foil etched away) to achieve a dry film thickness of 30 μm. After drying at 80°C for 30 min, it was allowed to cool naturally to room temperature. Using an off-contact exposure apparatus equipped with an ultra-high pressure mercury lamp (5 kW short arc lamp), a 300 × 300 μm pattern was exposed to the substrate with the aforementioned optimal exposure. A 1 wt% Na₂CO₃ aqueous solution at 30°C was developed for 120 s at a spray pressure of 0.2 MPa, followed by thermal curing at 150°C for 60 min. This resulted in a 300 × 300 μm pattern on the FR-4 substrate, which served as the evaluation sample.

[0109] Sheet resistance: The sheet resistance of a sample is measured and evaluated using a sheet resistance meter.

[0110] Table 1

[0111]

[0112]

[0113] As shown in Table 1:

[0114] The photosensitive conductive resin compositions provided in Examples 1-7 of this invention produce photosensitive conductive films with excellent peel strength and conductivity; wherein the peel strength is 4.3-6.5 N / cm and the sheet resistance is 30-150 Ω, and under preferred conditions the peel strength is 5.0-6.5 N / cm and the sheet resistance is 30-90 Ω.

[0115] A comparison of Examples 1 and 6-7 shows that when the average particle size of the conductive carbon filler is too small, the conductive channels are difficult to form, resulting in a larger sheet resistance of the photosensitive conductive film; when the average particle size of the conductive carbon filler is too large, the bonding force between carbon black and copper is poor, resulting in a lower peel strength of the photosensitive conductive film.

[0116] As can be seen from Comparative Example 1, when the volume resistivity of conductive carbon fillers is too high, the sheet resistance of the photosensitive conductive film is too high and the conductivity decreases due to the poor conductivity of conductive carbon fillers.

[0117] As can be seen from the comparison between Example 2 and Comparative Example 2, when the content of conductive carbon filler is too low, insufficient conductive channels cannot be formed, resulting in an excessively high sheet resistance of the photosensitive conductive adhesive film and a decrease in conductivity. As can be seen from the comparison between Example 1 and Comparative Example 3, when the content of conductive carbon filler is too high, the poor adhesion of the conductive filler leads to a low bonding force between the photosensitive conductive adhesive film and the circuit board, causing the pattern to fall off and making testing impossible.

[0118] As can be seen from the comparison of Comparative Example 4, when no additives are added, the viscosity of the photosensitive conductive film made by the resin composition is too high, resulting in a low bonding force between the photosensitive conductive film and the circuit board, causing the pattern to fall off and making it impossible to conduct tests.

[0119] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A photosensitive conductive resin composition, characterized in that, The photosensitive conductive resin composition comprises the following components in parts by weight: The volume resistivity of the conductive carbon filler is ≤0.5Ω·m.

2. The photosensitive conductive resin composition according to claim 1, characterized in that, The photosensitive polymer includes an epoxy resin containing unsaturated double bonds and carboxyl groups; Preferably, the epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, phosphorus-containing epoxy resin, MDI-modified epoxy resin, phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, or alicyclic epoxy resin.

3. The photosensitive conductive resin composition according to claim 1 or 2, characterized in that, The acrylate monomers include acrylates with at least a bifunctional group.

4. The photosensitive conductive resin composition according to any one of claims 1-3, characterized in that, The photoinitiator includes any one or a combination of at least two of the following: alkyl phenyl ketone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanoceramic photopolymerization initiators, or oxime ester photopolymerization initiators.

5. The photosensitive conductive resin composition according to any one of claims 1-4, characterized in that, The conductive carbon filler includes any one or a combination of at least two of single-walled carbon nanotubes, conductive carbon black, or graphene.

6. The photosensitive conductive resin composition according to any one of claims 1-5, characterized in that, The average particle size of the conductive carbon filler is 0.1-5 μm, more preferably 1-3 μm.

7. The photosensitive conductive resin composition according to any one of claims 1-6, characterized in that, The additives include any one or a combination of at least two of polyalkylammonium salts, polyesters, polyvinylpyrrolidone, or silicone oils.

8. A photosensitive conductive adhesive film, characterized in that, The material of the photosensitive conductive adhesive film includes the photosensitive conductive resin composition as described in any one of claims 1-7; Preferably, the photosensitive conductive adhesive film is obtained by coating the photosensitive conductive resin composition onto a release material and then drying and / or semi-curing it; Preferably, the photosensitive conductive adhesive film is further provided with a protective film on the side away from the release material.

9. A metal foil-coated laminate, characterized in that, The metal foil laminate includes at least one photosensitive conductive film as described in claim 8 and metal foil located on one or both sides of the laminated photosensitive conductive film.

10. A multilayer printed circuit board, characterized in that, The multilayer printed circuit board includes at least one photosensitive conductive film as described in claim 8 and a circuit board located on one or both sides of the multilayered photosensitive conductive film, or a circuit board located on one side of the multilayered photosensitive conductive film and a metal foil located on the other side.

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