Prepreg embedded with damping rubber film, method for producing the same, and printed circuit board

Abstract

This invention provides a prepreg with a damping rubber film laminated therein, and a printed circuit board containing the prepreg, enabling the prepreg to maintain good damping characteristics over a wide temperature range. Furthermore, when the printed circuit board containing the prepreg or damping rubber film is subjected to external force, its resonant amplification factor can be reduced by more than half, improving the stability and reliability of the printed circuit board.

Description

Technical Field

[0001] This invention relates to a prepreg embedded with a damping rubber film, a method for preparing the prepreg, and a printed circuit board containing the prepreg. Background Technology

[0002] With the rapid development of modern industry, reducing vibration and noise has become a crucial issue in various fields. Vibration not only reduces operational accuracy and affects product quality but can also shorten product lifespan or jeopardize safety. The application of damping materials can dissipate the energy of mechanical waves, thereby mitigating their harmful effects. In particular, with the increasing complexity of electronic devices, the demand for vibration reduction, especially in printed circuit boards (PCBs), is becoming increasingly strong. When external forces (such as vibration and impact) act on the PCB, the board may experience resonant amplification at specific frequencies, causing circuit fatigue or solder joint damage. Traditional vibration reduction measures are mostly focused on the overall system level, offering limited improvement to the inherent resonance problem of the PCB itself. Therefore, a method is needed to directly introduce damping materials into the PCB layer structure to effectively suppress resonance by enhancing the structural damping of the PCB itself. This has become a major technical challenge facing various fields.

[0003] The elastomer materials commonly used in vibration damping rubbers mainly include the following: natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene propylene diene monomer (EPDM), and butyl rubber (IIR). The influence of elastomer materials on vibration damping characteristics is considered from the perspective of rubber formulation. Besides the selection of rubber components, appropriate vulcanizing agents, fillers (such as carbon black and silica), and additives also need to be chosen.

[0004] The vulcanization process has a long and mature history. However, harmful sulfur-containing compounds are generated during the vulcanization process. Furthermore, rubber products cannot be incinerated at high temperatures after their service life, as the sulfur will inevitably turn into harmful gases or toxic residues. Adjusting the vulcanization system, increasing the type and content of fillers, and introducing additives such as antioxidants can significantly improve the fatigue life of rubber. The use of high-performance vulcanizing agents can shorten vulcanization time, reduce the amount of vulcanizing agent used, and increase crosslinking density, thereby enhancing fatigue resistance.

[0005] Generally, environmental factors such as temperature, humidity, and oxygen content all affect the fatigue properties of rubber. High temperatures intensify the movement of rubber molecular chains, easily leading to stress relaxation and aging; low temperatures cause rubber to harden, reduce toughness, and become brittle. To date, various studies have been conducted to reduce vibration in fields such as precision instrument protection, electronic components, and optical systems. However, with the continuous development of industry, the application scenarios of printed circuit boards extend beyond daily use to include more complex scenarios such as underwater environments, high altitudes, and fire zones. Research on the vibration damping characteristics of damping rubber in extreme working environments remains incomplete.

[0006] Furthermore, traditional block or thick sheet rubber materials have limited adaptability. Thin-film high-damping materials, on the other hand, can be more flexibly bonded or composited into the layer structure of printed circuit boards, achieving precise control of vibration and noise. However, current processes cannot simultaneously accommodate both the structure of the printed circuit board and its high-damping characteristics.

[0007] For example, Patent Document 1 relates to the field of vibration reduction technology for electric generators. Through improved formulations and preparation methods, the resulting product exhibits excellent mechanical properties and is wear-resistant and aging-resistant. This vibration damping pad for electric generators is made from the following raw materials in parts by weight: 50-60 parts nitrile rubber, 40-50 parts polyurethane rubber, 2-3 parts stearic acid, 2-3 parts dioctyl adipic acid, 4-6 parts zinc oxide, 1-2 parts glass fiber, 8-12 parts calcined clay, 8-12 parts microcrystalline cellulose, 8-12 parts silica, 2-4 parts vulcanizing agent, 3-5 parts palm wax, 2-5 parts microcrystalline wax, and 2-4 parts antioxidant. The tensile properties and hardness, among other physical properties, of the products prepared in Examples 1-8 and Comparative Examples 1-2 under 150°C hot air aging conditions were evaluated. However, the damping characteristics under low-temperature conditions were not evaluated. Furthermore, given the relatively uniform operating environment of electric generators, this patent document did not consider the impact of extreme low-temperature environments on the vibration damping pad. Meanwhile, the shock-absorbing pads for electric generators obtained in this patent document are difficult to adapt to the special requirements of thinner and lighter anti-vibration components in printed circuit boards.

[0008] Furthermore, for example, Patent Document 2 relates to an elastomer composition with acoustic attenuation properties. This one-component thermosetting reactive composition consists of a liquid rubber with reactive olefinic double bonds, a solid rubber as needed, and a sulfur-based vulcanization system. It exhibits a high acoustic dynamic loss coefficient in the vulcanized state over a wide operating temperature range, approximately +10°C to +40°C. These compositions can be used as acoustic attenuation adhesives, sealants, or coating materials. However, in this patent document, the elastomer composition, when used as a coating, is formed on the surface of the components by spraying or extrusion and then heated to form the coating, which is difficult to adapt to the process requirements of continuous production of general printed circuit boards. Furthermore, it only focuses on the acoustic attenuation value (d-combi) and does not consider the impact of extreme low-temperature environments on the vibration reduction effect.

[0009] It is evident that commonly used rubber materials currently struggle to simultaneously achieve high damping performance across a wide temperature range. This results in an inability to improve the structural damping of printed circuit boards (PCBs) and reduce the resonant amplification factor under extreme environments (wide operating temperature ranges, such as high temperatures up to 70°C and low temperatures down to -25°C). Furthermore, there are no publicly available or teaching methods for adding damping rubber films suitable for PCB manufacturing processes. Therefore, designing and preparing a prepreg embedded with a damping rubber film that maintains a damping loss factor greater than 0.5 and excellent uniformity within a temperature range of -25°C to 70°C, and its preparation method, has become a pressing problem in this field.

[0010] Existing technical documents

[0011] Patent Document 1: CN 108794834 B

[0012] Patent Document 2: JP Patent No. 10-509755 Summary of the Invention

[0013] The technical problem that the invention aims to solve

[0014] As mentioned above, none of the technologies disclosed in the aforementioned patent documents consider a prepreg with stable vibration damping performance over a wide operating temperature range (e.g., high temperatures up to 70°C and low temperatures down to -25°C). Therefore, the technical problem this invention aims to solve is to provide a prepreg with a damping rubber film laminated therein, and a printed circuit board containing the prepreg or damping rubber film, enabling the prepreg or damping rubber film to maintain good damping characteristics over a wide temperature range. Furthermore, when the printed circuit board containing the prepreg or damping rubber film is subjected to external force, its resonant amplification factor can be reduced by more than half (the root mean square value of random vibration (RMS) decreases by more than half), improving the stability and reliability of the printed circuit board.

[0015] Solutions for solving technical problems

[0016] In view of the above-mentioned technical problems, the inventors of this application have made continuous and painstaking research, and as a result, proposed a damping rubber film layered between two prepregs on a printed circuit board, wherein the thickness of the damping rubber film is 0.05-0.3mm, and the damping loss factor is maintained above 0.5 at -25℃ to 70℃.

[0017] That is, the present invention relates to the following technical solutions.

[0018] This invention provides a prepreg with a damping rubber film for printed circuit boards, characterized in that:

[0019] The damping rubber film is stacked between two prepreg sheets on the printed circuit board.

[0020] The thickness of the damping rubber film is 0.05-0.3 mm.

[0021] The damping rubber film is formed from a damping rubber composition with nitrile rubber as the main rubber component.

[0022] The damping rubber composition also includes a vulcanizing agent, a plasticizer, a reinforcing filler, and an anti-aging agent.

[0023] The acrylonitrile (ACN) content in the nitrile rubber is greater than 30% and less than 60% by percentage, and the Mooney viscosity of the nitrile rubber is greater than 60 and less than 120.

[0024] The vulcanizing agent is selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents.

[0025] The plasticizer is selected from one or more of ester plasticizers and petroleum resins, wherein the ester plasticizer is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms.

[0026] The film maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25°C to 70°C.

[0027] According to embodiments of the present invention, the content of rubber component in the damping rubber composition is 40-90% by weight.

[0028] According to an embodiment of the present invention, the content of the vulcanizing agent in the damping rubber composition is 1-30 parts by weight per 100 parts by weight of rubber component.

[0029] According to an embodiment of the present invention, the content of plasticizer in the damping rubber composition is 1-20 parts by weight per 100 parts by weight of rubber component.

[0030] According to an embodiment of the present invention, the content of reinforcing filler in the damping rubber composition is 1-50 parts by weight per 100 parts by weight of rubber component.

[0031] According to an embodiment of the present invention, the content of the anti-aging agent in the damping rubber composition is 10-60 parts by weight per 100 parts by weight of rubber component.

[0032] The present invention provides a method for preparing a prepreg, comprising: a step of laminating a damping rubber film between two prepregs and laminating them at 10-25°C and 0.1-1.5 MPa pressure.

[0033] According to an embodiment of the present invention, the damping rubber film is obtained by hot-pressing and vulcanizing a pre-formed rubber film with a thickness of 0.05-0.3 mm, which has been cast into a film, at 120-200°C and 3-15 MPa.

[0034] The present invention provides a printed circuit board comprising one or more layers of the prepreg or one or more layers of damping rubber film.

[0035] According to an embodiment of the present invention, its resonant amplification factor is reduced by more than half compared to a printed circuit board containing a prepreg of equal thickness.

[0036] Invention Effects

[0037] According to the technical solution of the present invention, a prepreg with stable vibration damping effect over a wide range and unaffected by environmental changes can be obtained. Without significantly increasing PCB thickness or adversely affecting electrical performance, the PCB resonance amplification factor is greatly reduced (significantly reducing the random root mean square (RMS) value), thereby improving vibration damping performance and service life. Furthermore, the manufacturing process is compatible with existing PCB manufacturing processes, requiring only the addition of a damping rubber film lamination step during the stacking process, making it economical and efficient. Detailed Implementation

[0038] The present invention is further illustrated below by way of embodiments, but it should be understood that these specific examples are not intended to limit the scope of the invention in any way. It should be noted that, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and their quality meets national standards. Unless otherwise specified in the present invention, content refers to weight percentage or weight ratio.

[0039] The prepreg of the present invention comprising a damping rubber film is formed by stacking a damping rubber film with a thickness of 0.05-0.3 mm between two prepregs on a printed circuit board. The damping rubber film is formed from a damping rubber composition with nitrile rubber as the main rubber component.

[0040] [Damping rubber composition]

[0041] The damping rubber composition of the present invention uses nitrile butadiene rubber (NBR) as the main rubber component and contains 1-30 parts by weight of vulcanizing agent, 1-20 parts by weight of plasticizer, 1-50 parts by weight of reinforcing filler, and 10-60 parts by weight of anti-aging agent relative to 100 parts by weight of the rubber component. The nitrile butadiene rubber has an acrylonitrile (ACN) content greater than 30% and less than 60%, and a Mooney viscosity greater than 60 and less than 120. The vulcanizing agent is selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents. The plasticizer is selected from one or more of ester plasticizers, petroleum resins, etc., and the ester plasticizer is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms.

[0042] <Rubber Composition>

[0043] The damping mechanism of rubber materials is due to energy dissipation caused by intermolecular friction when molecular chains move under alternating stress. Nitrile butadiene rubber (NBR), containing a large number of side methyl groups and polar side groups, has a high tanδ and excellent damping performance, making it widely used in vibration damping materials. However, generally, the damping factor of a single rubber is very small, and its glass transition temperature (Tg) range is narrow, resulting in a narrow effective damping temperature range. Therefore, it is difficult to prepare high-performance damping materials using only a single rubber; usually, blending with other rubber materials is necessary to improve the damping performance.

[0044] This invention, through dedicated research, has yielded a damping rubber film obtained by blending nitrile rubber as the main rubber component with a specific vulcanizing agent and incorporating specific anti-aging agents and other components. This film achieves excellent damping performance over a wide temperature range, a surprising achievement in the field. In this invention, using nitrile rubber as the main rubber component means that the content of nitrile rubber in the rubber component is 50% or more by weight, preferably 60% or more, more preferably 65% ​​or more, more preferably 80% or 90% or more. In the most preferred embodiment of this application, the rubber component consists solely of nitrile rubber.

[0045] Nitrile rubber is a copolymer polymerized from acrylonitrile and butadiene monomers. The acrylonitrile content of nitrile rubber affects its polarity, chain flexibility, interchain interactions, and the content of double bonds within the molecular chain. The nitrile rubber used in this invention has an acrylonitrile (ACN) content of 30–60% (weight percentage), preferably 31–50%, and most preferably below 45%.

[0046] By using the acrylonitrile rubber specified in this invention, good processability can be achieved, and excellent cold resistance can be maintained. The damping loss factor of the damping rubber material can still be maintained in cold environments as low as -25°C.

[0047] The Mooney viscosity of the nitrile rubber of the present invention is greater than 60 and less than 120, preferably greater than 72 and less than 105, and most preferably less than 100.

[0048] By using the nitrile rubber with the Mooney viscosity specified in this invention, good film-forming properties and uniform texture can be achieved, making it suitable for a wider range of applications. Furthermore, it maintains excellent heat and cold resistance.

[0049] In the damping rubber composition of the present invention, the rubber component is 40-90% by weight, preferably 45-80%, and more preferably 48-70%.

[0050] <Vulcanizing Agent>

[0051] Vulcanizing agents are substances that enable rubber to undergo vulcanization (crosslinking). They are broadly classified into inorganic and organic categories. Inorganic vulcanizing agents include sulfur, sulfur monochloride, selenium, tellurium, etc. Organic vulcanizing agents include organic peroxides (such as benzoyl peroxide), quinone oxime compounds, resin-based vulcanizing agents, etc. Inorganic vulcanizing agents containing excessive amounts of elemental sulfur and sulfur-containing compounds have adverse environmental pollution characteristics, such as the emission of harmful gases.

[0052] The present invention uses a vulcanizing agent selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents, preferably containing resin-based vulcanizing agents. By forming C-C bonds and ether bonds with high thermal stability, the heat resistance and other properties of vulcanized rubber can be improved.

[0053] In the vulcanization process of nitrile rubber, the peroxide vulcanization system can produce rubber compounds with low compression set, fast vulcanization speed, and resistance to hot air aging. This invention can use commonly used peroxide vulcanizing agents, such as alkyl peroxides, diacyl peroxides (benzoyl peroxide (BPO)), and peroxide esters. Specific peroxide vulcanizing agents include dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane.

[0054] When used as a quinone oxime compound vulcanizing agent in the vulcanization of nitrile butadiene rubber, it can achieve better physical and mechanical properties, especially better heat aging resistance. Specifically, p-benzoquinone dioxime, etc., can be used.

[0055] As a resin-based vulcanizing agent, one or more phenolic resin-based vulcanizing agents are preferred, and one or more phenol-formaldehyde resins are more preferred. Examples of phenol-formaldehyde resins include unsubstituted phenol-formaldehyde resins and alkyl-substituted phenol-formaldehyde resins (alkyl groups with 1-15 carbon atoms). The alkyl-substituted phenol-formaldehyde resin may have 1-3 alkyl groups as substituents, and the alkyl groups may be substituted with halogens (alkyl groups with 1-15 carbon atoms). As a resin-based vulcanizing agent, better physical and mechanical properties can be obtained, especially better heat aging resistance. The film vulcanized with the resin-based vulcanizing agent of the present invention achieves good film-forming properties and has a uniform texture.

[0056] The amount of vulcanizing agent used in the damping rubber composition of the present invention is 1-30 parts by weight based on 100 parts by weight of rubber component, preferably 2-28 parts by weight, more preferably 5-27 parts by weight, and most preferably 10-25 parts by weight.

[0057] <Plasticizer>

[0058] The use of plasticizers can significantly improve the mixing performance and molding properties of NBR during processing, such as calendering, extrusion, and injection molding. Plasticizers can also improve polymer processing performance and tensile properties; reduce viscosity, lower hardness and modulus, increase flowability, and improve cold resistance. This invention uses plasticizers selected from one or more of ester plasticizers and petroleum resins. By adding plasticizers, the intermolecular forces of NBR can be weakened, thereby lowering the rubber's Tg, facilitating the casting of the damping rubber composition into a uniformly thick film. Simultaneously, in synergy with vulcanizing agents, NBR is endowed with higher elasticity, lower heat generation, and improved cold resistance.

[0059] The ester plasticizer is preferably selected from one or more esters formed by polycarboxylic acids having two or more carboxyl groups and alcohols having 1-20 carbon atoms.

[0060] Examples of ester plasticizers include ester plasticizers formed from phthalic acid and alcohols with 1-20 carbon atoms, and fatty acid esters formed from fatty acids with two or more carboxyl groups and alcohols with 1-20 carbon atoms.

[0061] The phthalate plasticizers described herein possess excellent compatibility and plasticizing effects. The phthalate plasticizers are selected from one or more of dibutyl phthalate (DBP), dioctyl phthalate, etc. The fatty acid ester plasticizers are selected from one or more of dioctyl sebacate, diisooctyl sebacate, di-n-hexyl sebacate, di-n-butyl sebacate, etc.

[0062] Petroleum resins have good plasticizing effects and processing performance, and can improve the hardness, wear resistance and weather resistance of films.

[0063] The amount of plasticizer used in the damping rubber composition of the present invention is 1-20 parts by weight, preferably 5-18 parts by weight, and more preferably 6-15 parts by weight, based on 100 parts by weight of the rubber component.

[0064] <Reinforcing Filler>

[0065] The damping coefficient and modulus of reinforcing fillers are closely related to those of nitrile rubber. During deformation, internal friction between macromolecular chain segments and fillers, as well as between fillers themselves, alters the damping properties of the vulcanizate. The particle size and other morphological characteristics of the fillers also affect the damping performance.

[0066] The reinforcing filler of this invention is preferably an inorganic reinforcing filler, which is selected from one or more of the following: clay, calcium carbonate, magnesium carbonate, alumina, talc, mica powder, graphite, carbon black, and silica. For example, hard clay is inexpensive and has a significant reinforcing effect. Alumina containing water is an excellent reinforcing filler for heat-resistant formulations of nitrile rubber.

[0067] Among them, silica, or amorphous silica, is a white, non-toxic fine powder with excellent properties such as porosity, high dispersibility, light weight, good chemical stability, and high temperature resistance. Silica is an effective reinforcing filler for NBR, effectively improving the tensile strength and tear strength of the vulcanizate. However, it is generally believed that using carbon black and silica to reinforce NBR also affects its heat resistance. This invention breaks through this technical understanding.

[0068] The inorganic reinforcing filler of the present invention has a particle size of 1-100 micrometers, preferably 1-80 micrometers, and more preferably 1-60 micrometers.

[0069] The amount of reinforcing filler used in the damping rubber composition of the present invention is 1-50 parts by weight, preferably 5-40 parts by weight, and more preferably 8-30 parts by weight, based on 100 parts by weight of the rubber component.

[0070] Anti-aging agents

[0071] NBR is prone to thermo-oxidative aging during use due to changes in environmental factors such as heat, oxygen, light, and water. This leads to a decline in mechanical and physicochemical properties, affecting the performance of the finished product. When rubber ages, its molecular chains continuously degrade and cross-link. If the decomposition rate is too high, the molecular weight of the rubber will decrease, resulting in sticky products and reduced strength. Conversely, the surface will harden and lose elasticity. Adding antioxidants to the rubber can delay aging.

[0072] The anti-aging agent used in this application is selected from one or more of the following: phenols, polydihydroquinolines, amines, and imidazoles.

[0073] Among them, one or more of the following are preferred: hindered phenols, bisphenol hindered phenols, triphenol hindered phenols, hydroquinone, polydihydroquinoline, diphenylamine, p-phenylenediamine, mercaptobenzimidazole and their salts.

[0074] Specific anti-aging agents include one or more of the following: hindered phenol AO60, hindered phenol AO-70, hindered phenol AO-80, bisphenol hindered phenol 2246, triphenol-type hindered phenol 3114, 3125, 330, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (4020), N-cyclohexyl-N'-phenyl-p-phenylenediamine (4010), 2-mercaptobenzimidazole (MB), and 2-mercaptobenzimidazole zinc salt (MBZ).

[0075] The amount of anti-aging agent used in the damping rubber composition of the present invention is 10-60 parts by weight based on 100 parts by weight of rubber component, preferably 20-60 parts by weight, more preferably 25-55 parts by weight, and most preferably 30-55 parts by weight.

[0076] <Other Additives>

[0077] In the damping rubber composition of the present invention, conventional additives in the art, such as lubricants, vulcanization accelerators, and tackifiers, may be added as needed. The amount of other additives in the damping rubber composition of the present invention is 0-20 parts by weight per 100 parts by weight of the rubber component, preferably 0.1-10 parts by weight, and more preferably 0.5-5 parts by weight.

[0078] [Preparation method of prepreg with damping rubber film]

[0079] The prepreg of the present invention with a damping rubber film is obtained by laminating a damping rubber film between two prepregs and then laminating them at 10-25°C and 0.1-1.5 MPa pressure. The damping rubber film is obtained by hot-pressing and vulcanizing a pre-formed film with a thickness of 0.05-0.3 mm, which has been cast, at 120-200°C and 3-15 MPa.

[0080] Damping Rubber Film and its Manufacturing Process

[0081] The method for preparing the damping rubber film of the present invention includes a step of preparing a rubber solution, a preforming step, and a hot-pressing vulcanization step, thereby obtaining a film that maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25°C to 70°C. The damping rubber film of the present invention can be easily cut or subjected to further coating or lamination operations.

[0082] Specifically, the preparation method of the damping rubber film includes the following steps:

[0083] The process of preparing the adhesive solution: Dissolve the damping rubber composition with nitrile rubber as the main rubber component in a solvent to form an adhesive solution;

[0084] Pre-forming process: The adhesive liquid is coated and dried using a casting method to form a pre-formed adhesive film with a thickness of 0.05-0.3 mm;

[0085] Hot-press vulcanization process: The pre-formed film is hot-pressed and vulcanized at 120-200℃ and 3-15MPa. adhesive Preparation process

[0086] The components of a damping rubber composition with nitrile rubber as the main rubber component are chopped to an equivalent projected area diameter of 0.5-2 cm and then added to a solvent to form a uniform adhesive solution.

[0087] As a solvent of the present invention, any solvent that can be uniformly mixed with each component of the damping rubber composition to form a liquid and can evaporate quickly during the casting process is acceptable. Preferably, one or more organic solvents are used, and more preferably one or more organic solvents selected from toluene, methyl ethyl ketone, cyclohexanone, etc. The viscosity of the liquid can be adjusted according to the film thickness and equipment requirements.

[0088] The amount of solvent used is 0.5-5 times the total weight of the rubber damping composition, preferably 0.7-4 times.

[0089] To ensure uniform mixing, conventional mixing methods such as stirring can be used. There are no special requirements for the mixing temperature, but it is preferably 20-60℃, and more preferably 25-50℃.

[0090] Viscosity modifiers can be added as needed. There are no special restrictions on the types of viscosity modifiers, but examples include polyethylene oxide (PEO) and sodium polyacrylate (PNaAA).

[0091] Casting film process

[0092] On a casting apparatus (such as a casting machine), the adhesive is evenly applied to the surface of the substrate to initially form a wet film.

[0093] The solvent in the wet film is evaporated by constant temperature drying, uniform heating, or segmented heating, with the drying temperature below 80℃, preferably between 30-80℃, to ensure sufficient solvent evaporation and prevent premature cross-linking of the material during the drying process. A pre-formed film is obtained, with a thickness controllable in the range of 0.05-0.3mm.

[0094] Pressure vulcanization process

[0095] The pre-formed rubber film is placed in a vulcanizing machine and hot-pressed for 10-40 minutes at a vulcanization temperature of 120-200℃ and a pressure of 3-15MPa. Vulcanization temperature is a fundamental condition for the vulcanization reaction of rubber; higher vulcanization temperatures result in faster vulcanization and higher production efficiency. Conversely, lower temperatures lead to slower vulcanization and lower production efficiency. If the temperature exceeds 200℃, the high-temperature rubber molecular chains will break down, leading to vulcanization regression. If the temperature is below 120℃, the vulcanization reaction efficiency will decrease. The preferred vulcanization temperature is 130-180℃, more preferably 140-170℃. The preferred pressure is 4-12MPa, more preferably 6-9MPa. The preferred vulcanization time is 15-30 minutes, more preferably 15-25 minutes.

[0096] After vulcanization, a stable cross-linked damping rubber film is formed. The damping rubber film of the present invention maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25°C to 70°C. The damping rubber film of the present invention can achieve stable vibration reduction performance and has a uniform texture over a wide operating temperature range, including extreme environments.

[0097] <Prepreg and its preparation process>

[0098] The sheet used for prepreg in this invention is an insulating dielectric layer mainly composed of resin and reinforcing materials (such as glass fiber). The sheet for prepreg can be manufactured by conventional methods, for example, by impregnating reinforcing materials such as glass cloth in a varnish containing a resin composition with thermosetting resin as the main component in a solvent, and then pre-curing it using conventional methods (such as a high-temperature oven).

[0099] There are no particular limitations on the reinforcing material used in this invention. Examples include fiber fabrics formed from synthetic fibers such as glass fibers, aramid fibers, polyester fibers, aromatic polyester fibers, and fluoropolymers, as well as metal fibers, carbon fibers, and mineral fibers. Among these, glass fiber fabrics formed from glass fibers are preferred.

[0100] There are no particular limitations on the aforementioned thermosetting resins. Epoxy resins or their derivatives (such as halides), cyanate ester resins, bismaleimide resins, phenolic resins, benzoxazine resins, vinyl benzyl ether resins, benzocyclobutene resins, etc., can be used. Generally, it is preferred to include epoxy resins or their halides and other derivatives. Other thermosetting resins can also be used in combination as appropriate.

[0101] <Lamination process of prepreg with damping rubber film>

[0102] A method for preparing a prepreg containing a damping rubber film includes: laminating a damping rubber film between two prepreg layers and performing lamination at 10–25°C and 0.1–1.5 MPa pressure. The lamination conditions can be fine-tuned according to the PCB material system and film properties. The lamination time is preferably 15–40 minutes, more preferably 18–35 minutes. The lamination temperature is preferably 10–20°C. The lamination pressure is preferably 0.5–1.2 MPa. The damping rubber film is embedded or laminated between two prepreg layers through the lamination process.

[0103] Depending on the needs, a coupling agent, such as KH-550 (γ-aminopropyltriethoxysilane), can be added between the damping rubber film and the prepreg to improve the bonding strength.

[0104] Printed Circuit Board

[0105] In this invention, a printed circuit board (PCB) is an electronic interconnect carrier that forms conductive lines on the surface of an insulating substrate through pattern transfer and etching processes. Based on the number of conductive layers, PCBs can be classified as single-sided boards (single-layer), double-sided boards (double-layer), and multilayer boards (≥3 layers). PCBs are manufactured using a thermal lamination process: a core board with etched circuitry is alternately laminated with an adhesive layer (prepreg), and then cured under high temperature and pressure in a vacuum hot press to form an integral structure. Interlayer interconnection is achieved using through-hole plating or a multilayer lamination method.

[0106] The printed circuit board of the present invention can be obtained using conventional manufacturing methods in the art.

[0107] The manufacturing process of the printed circuit board of the present invention includes a core board pretreatment process, an adhesive layer pretreatment process, a thermal lamination process, and a post-treatment process.

[0108] Core board pretreatment process

[0109] (1) Selection of core board: Typically, a composite material formed by reinforcing materials and resin (specific materials are as described above in the description of the reinforcing materials and resins forming the prepreg, for example, formed by glass fiber and epoxy resin or its derivatives) and copper foil are pressed together under high temperature and pressure to serve as the base carrier for the conductive layer. Single-sided or double-sided copper-clad core boards can be selected as needed, and the board thickness and quantity can be selected, and the dimensions can be cut as required.

[0110] (2) Pattern transfer and etching: Dry film imaging—film application, exposure, and development to form resist patterns. Etching—using acidic etching solution to remove unprotected copper layers and form circuit lines.

[0111] (3) Treatment of blind holes and buried holes: Drill holes on specific core boards as needed and perform metallization treatment. First, copper plating is performed—a thin copper layer is deposited on the hole wall to enhance conductivity; then, electroplating is performed to thicken the copper layer—the thickness of the copper layer is increased by electroplating to improve conductivity and reliability.

[0112] Pretreatment process of adhesive layer

[0113] (1) The prepreg serves as an adhesive layer, used in the subsequent hot lamination process to bond the core layers together. The prepreg can be a single layer or a stack of two or more sheets. Furthermore, the materials used to form each sheet can be the same or different. The sheets are primarily composed of resin and reinforcing materials, as detailed above.

[0114] As described in "Preservative Sheets and Their Preparation Process". Select the thickness and quantity as needed, and cut to the required size.

[0115] (2) Add a layer of damping rubber film of the present invention between the two layers of prepreg as a damping adhesive layer; or directly select a prepreg with damping rubber film prepared as described in the previous "Lamination process of prepreg with damping rubber film" as a damping adhesive layer. Select the thickness and quantity as needed, and cut the size as required.

[0116] (3) As needed, multiple layers of damping adhesive can also be added to increase the overall damping performance of the PCB.

[0117] Hot lamination process

[0118] (1) Stack all the core boards and adhesive layers in the required order and perform hot lamination at 170-180℃ and 2.0-2.8MPa pressure for no less than 30 minutes. The hot lamination conditions can be finely adjusted according to the PCB material system and film properties.

[0119] Post-processing

[0120] (1) Via treatment: Drill holes according to application requirements and perform metallization treatment. First, copper plating is performed—a thin copper layer is deposited on the hole wall to enhance conductivity; then, electroplating is performed to thicken the copper layer—the thickness of the copper layer is increased by electroplating to improve conductivity and reliability.

[0121] (2) Surface treatment: Depending on the application requirements, gold plating, tin plating or immersion gold plating processes can be selected for the top and bottom layers.

[0122] (3) Structural processing: According to structural requirements, the PCB is subjected to mechanical processing such as cutting, grooving, and drilling.

[0123] The following describes specific embodiments of the present invention using a double-sided printed circuit board or a four-layer printed circuit board as examples.

[0124] Method for fabricating double-sided printed circuit boards

[0125] As one implementation method, the structure of a double-sided printed circuit typically consists of two core boards:

[0126] [Top Layer] Copper foil is applied to one side (top surface) of the sheet material (e.g., using FR-4 material).

[0127] [Bottom Layer] Copper foil is applied to one side (bottom surface) of the sheet material (e.g., using FR-4 material).

[0128] For the printed circuit board of the present invention, according to the aforementioned process, a prepreg is added as an adhesive layer on the lower surface of the top layer and the upper surface of the bottom layer, and a damping rubber film is added between the two prepreg layers (or the prepreg with damping rubber film of the present invention can be used directly between the two core boards), and then a double-sided printed circuit board is formed according to the above-mentioned thermal lamination process.

[0129] Method for fabricating four-layer printed circuit boards

[0130] As another implementation, the structure of a four-layer printed circuit board typically consists of three core layers:

[0131] [Top Layer] Copper foil is applied to one side (top surface) of the sheet material (usually FR-4 material).

[0132] [Inner Layer] Copper foil is applied to both sides of the sheet (usually FR-4 material). The upper surface is inner layer 1, and the lower surface is inner layer 2.

[0133] [Bottom Layer] Copper foil is applied to one side (bottom surface) of the sheet material (usually FR-4 material).

[0134] For the printed circuit board of the present invention, referring to the aforementioned process, a prepreg layer is first added as an adhesive layer to the lower surface of the top layer and the upper surface of the inner layer. A damping rubber film is then bonded between these two prepreg layers. Next, a prepreg layer is added to the lower surface of the inner layer and the upper surface of the bottom layer, and a damping rubber film is also bonded between these two prepreg layers. That is, the layers are stacked in the following order from top to bottom: top layer—prepreg—damping film—prepreg—inner layer—prepreg—damping film—prepreg—bottom layer. Finally, a four-layer printed circuit board is formed according to the above lamination process. Similarly, the prepreg with damping rubber film of the present invention can also be used directly between the top and inner layers, and between the inner and bottom layers.

[0135] In other embodiments, the inner layer may also be in the form of two sheets with copper foil on one side, with a prepreg-damping film-prepreg structure added between the uncoated sides of the two sheets (or the prepreg with damping rubber film of the present invention can be added directly).

[0136] Example

[0137] The present invention will be described in more detail below through examples and comparative examples, but the present invention is not limited to these examples. In accordance with the preferred embodiments of the present invention, those skilled in the art can make appropriate adjustments to the formulation, lamination sequence, and pressing parameters according to different application requirements without departing from the scope of protection of the present invention.

[0138] <Nitrile rubber>

[0139] Nitrile rubber 1: (NBR3308, acrylonitrile content 32%-35%, Mooney viscosity 75-85, manufacturer: Lanzhou Chemical Industry Co., Ltd.)

[0140] Nitrile rubber 2 (NBR3606, acrylonitrile content 36%-40%, Mooney viscosity 65-80, manufacturer: Lanzhou Chemical)

[0141] Nitrile rubber 3: (NBR1704 acrylonitrile content 17-20%, Mooney viscosity 40-65, manufacturer: Lanzhou Chemical)

[0142] Nitrile rubber 4: (trade name: Russian 2665, acrylonitrile content 27%–30%, Mooney viscosity 60–70)

[0143] <Vulcanizing Agent>

[0144] Sulfur (powder, Luoyang Tianzhidao New Material Technology Co., Ltd.)

[0145] Dicumyl peroxide (DCP, Xiangyun Chemical)

[0146] Resin vulcanizing agent 1: (Phenolic resin, Hebei Zetian Chemical Co., Ltd.)

[0147] Resin vulcanizing agent 2: (SP1045, Lianhui Chemical)

[0148] <Plasticizer>

[0149] DMP (Dimethyl Phthalate, Shanghai Huafutai Chemical Co., Ltd.)

[0150] DBP: (Dibutyl Phthalate, Shandong Yousuo Chemical Technology Co., Ltd.)

[0151] DOS: (Dioctyl sebacate, Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd.)

[0152] <Reinforcing Filler>

[0153] Silica 1 (particle size: 48 microns, Shanghai Puni Industrial Co., Ltd.)

[0154] Silica 2 (Particle size: 1.6 microns, Hengtai Plastic Raw Materials Co., Ltd.)

[0155] Silica 3 (particle size: 0.5 microns, Jinan Delan Chemical Co., Ltd.)

[0156] Anti-aging agents

[0157] Hindered phenol AO60 (Shanghai Kaiyin Chemical)

[0158] Bisphenol-hindered phenol 2246 (Guangzhou Yuanda)

[0159] Triphenol-type hindered phenol 3114 (Shanghai Boyer Chemical Co., Ltd.)

[0160] 2,2,4-Trimethyl-1,2-Dihydroquinoline Polymer (RD) (Shandong Yousuo Chemical Technology Co., Ltd.)

[0161] 2-Mercaptobenzimidazole (MB) (Zhejiang Huangyan Zhedong Rubber Additives Co., Ltd.)

[0162] N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (4020) (Shijiazhuang Anhui Chemical Technology Co., Ltd.) N-Cyclohexyl-N'-phenyl-p-phenylenediamine (4010) (Shandong Yousuo Chemical Technology Co., Ltd.)

[0163] <Determination Method>

[0164] <Determination of Damping Factor>

[0165] In characterizing the damping performance of elastomers, the tangent of the phase angle δ (also known as the mechanical loss angle) between strain lag and stress is generally used as the damping factor to describe the magnitude of the material's internal friction. The magnitude of the internal friction of an elastomer material can be expressed as:

[0166]

[0167] In the formula: E″ represents the loss modulus, and E′ represents the energy storage modulus.

[0168] This invention utilizes a MAK-04 viscoelastic spectrometer manufactured by Metravib, France. A vertical load of 50 N is applied, and the displacement and load are reset to zero. The vibration frequency is then preloaded to 125 Hz, with an excitation amplitude of ±50 μm. Except for pre-forming the adhesive solution in a specified fixture, a damping rubber film of a specified size (15 mm long, 3 mm wide, 2 mm thick) is obtained as a sample according to the preparation method of the examples or comparative examples, and the damping factor is measured. The dynamic testing machine employs a single-point testing method and automatically records the damping loss factor (tanδ) of the sample. Refer to GJB981-1990.

[0169] <Resonance Amplification Factor>

[0170] Vibration tests mainly include sinusoidal vibration tests, random vibration tests, and three-dimensional vibration tests. A vibration table (frequency band 2Hz~3000Hz) and a control and detection system are used to conduct sinusoidal and random vibration tests on printed circuit boards, following GJB150.16A-2009 "Laboratory Environmental Test Methods for Military Equipment Part 16: Vibration Tests". Frequency range (2Hz~3000Hz), acceleration (20g), and displacement (≤51mm) are specified.

[0171] Example 1

[0172] Prepare the raw materials according to the formula shown in Table 1. Prepare 100g nitrile rubber, 2g sulfur, 20g resin vulcanizing agent 1, 10g DMP, 15g silica 1, 45g AO60, and 5g anti-aging agent 4010.

[0173] In the process of preparing the adhesive solution, the material is cut into small pieces of about 2cm, and the material is added to toluene at a ratio of 3 parts toluene per part of damping rubber composition. The mixture is stirred at room temperature for 60-90 minutes until a uniform adhesive solution is formed.

[0174] In the preforming process, the adhesive is evenly coated onto the surface of the substrate on a casting machine to initially form a wet film. The solvent in the wet film is evaporated by drying at a constant temperature of 80°C, resulting in a preformed adhesive film with a thickness of 0.12 mm.

[0175] In the hot-press vulcanization process, the rubber film is placed in a vulcanizing machine and hot-pressed for 15 minutes at 160℃ and 5MPa. The damping factor was measured using the aforementioned method, and the results showed that the loss factor of the obtained damping rubber film was above 0.52 in the range of -25℃ to 70℃.

[0176] Examples 2-4

[0177] In addition to adjusting the formula according to Table 1 to prepare each raw material (100g of nitrile rubber, and other components weighed according to the weight ratio or weight percentage shown in the table), the adhesive solution was prepared, pre-formed, and hot-pressed for vulcanization in the same manner as in Example 1. The tests were conducted in the same way, and the results are shown in Table 1.

[0178] Comparative Examples 1-4

[0179] In addition to preparing each raw material according to the adjusted formula in Table 1 (100g of nitrile rubber, and other components weighed according to the weight ratio or weight percentage shown in the table), the rubber solution was prepared, pre-formed, and hot-pressed vulcanized according to the mixing method in Example 1, and the same tests were performed. The results are shown in Table 1.

[0180] The composition of the damping rubber compositions of Examples 1-4 and Comparative Examples 1-4, and the measurement results of the obtained damping rubber films are shown in Table 1 below. All components are expressed in parts by weight or weight percentages.

[0181] Table 1

[0182]

[0183]

[0184] Example 5

[0185] Using the damping rubber film obtained in Example 3, a semi-cured sheet with a damping rubber film was prepared:

[0186] Two 0.14mm thick prepreg sheets, each 150mm x 150mm in size, and one damping rubber film obtained in Example 3, each 0.12mm thick and 150mm x 150mm in size, were selected. The damping rubber film was stacked between the two prepreg sheets and laminated at 15°C and 1.2MPa pressure for 30 minutes to obtain a prepreg sheet with a damping rubber film thickness of approximately 0.4mm.

[0187] Example 6

[0188] Using the damping rubber film obtained in Example 4, a semi-cured sheet with the damping rubber film was prepared:

[0189] Two 0.08mm thick prepreg sheets, each 150mm x 150mm in size, and one damping rubber film obtained in Example 4, each 0.12mm thick and 150mm x 150mm in size, were selected. The damping rubber film was laminated between the two prepreg sheets and pressed at 15°C and 1.2MPa pressure for 20 minutes to obtain a prepreg sheet with a damping rubber film thickness of approximately 0.28mm.

[0190] Example 7

[0191] Using the damping rubber film obtained in Example 1, a simple double-sided printed circuit board sample was made according to the aforementioned printed circuit board preparation process.

[0192] The pretreatment of each layer of material, from top to bottom, is as follows:

[0193]

Top Layer

[0194]

Adhesive Layer 1

[0195] [Damping layer] The damping rubber film obtained in Example 1 is selected, with a thickness of 0.12mm and a size of 150mm*150mm;

[0196]

Adhesive Layer 2

[0197] [Bottom Layer] A single-sided copper-clad FR4 core board is used, with dimensions of 150mm*150mm, board thickness of 0.6mm, copper thickness of 1oz, and the copper-clad side is the bottom layer;

[0198] Then, the circuit board samples were hot-pressed at 170℃ and 2.5MPa for 30 minutes, and a double-sided printed circuit board sample with a total thickness of about 1.6mm was produced through a hot lamination process.

[0199] Vibration tests were conducted on the entire printed circuit board sample according to the above method, and the total root mean square value of random vibration was measured. Compared with a PCB of the same thickness (the thickness of the damping rubber film is made up by the thickness of the prepreg) prepared in the same way except without the addition of the damping rubber film, the total root mean square value of random vibration of the PCB of the present invention decreased by about 55%, indicating that the resonance amplification factor was reduced by more than half, which can improve the performance stability of the product in complex vibration environment.

[0200] Example 8

[0201] Using the damping rubber film obtained in Example 2, a simple four-layer printed circuit board sample was made according to the aforementioned printed circuit board preparation process.

[0202] The pretreatment of each layer of material, from top to bottom, is as follows:

[0203]

Top Layer

[0204]

Adhesive Layer 1

[0205]

Damping layer 1

[0206]

Adhesive Layer 2

[0207]

Inner Layer

[0208]

Adhesive Layer 3

[0209]

Damping layer 2

[0210]

Adhesive Layer 4

[0211] [Bottom Layer] A single-sided copper-clad FR4 core board is used, with dimensions of 150mm*150mm, board thickness of 0.5mm, copper thickness of 1oz, and the copper-clad side is the bottom layer;

[0212] Then, the circuit board samples were hot-pressed at 170℃ and 2.5MPa for 45 minutes, and a four-layer printed circuit board sample with a total thickness of about 2.0mm was produced through a hot lamination process.

[0213] Vibration tests were conducted on the entire printed circuit board sample according to the above method, and the total root mean square value of random vibration was measured. Compared with a PCB of the same thickness (the thickness of the damping rubber film is made up by the thickness of the prepreg) except that no damping rubber film was added, the total root mean square value of random vibration of the PCB of the present invention decreased by about 71%, indicating that the resonance amplification factor was reduced by more than half, which can improve the performance stability of the product in complex vibration environment.

[0214] Example 9

[0215] Using the prepreg with damping rubber film obtained in Example 5, a simple double-sided printed circuit board sample was made according to the aforementioned printed circuit board preparation process.

[0216] The pretreatment of each layer of material, from top to bottom, is as follows:

[0217]

Top Layer

[0218] [Damping Adhesive Layer] A 0.4 mm thick semi-cured sheet with a damping rubber film obtained in Example 5 was selected, with a size of 150 mm * 150 mm;

[0219] [Bottom Layer] A single-sided copper-clad FR4 core board is used, with dimensions of 150mm*150mm, board thickness of 0.6mm, copper thickness of 1oz, and the copper-clad side is the bottom layer;

[0220] Then, the circuit board samples were hot-pressed at 170℃ and 2.5MPa for 30 minutes, and a double-sided printed circuit board sample with a total thickness of about 1.6mm was produced through a hot lamination process.

[0221] Vibration tests were conducted on the entire printed circuit board sample according to the above method, and the total root mean square value of random vibration was measured. Compared with a PCB of the same thickness (the thickness of the damping rubber film is made up by the thickness of the prepreg) except that no damping rubber film was added, the total root mean square value of random vibration of the PCB of the present invention decreased by about 56%, indicating that the resonance amplification factor was reduced by more than half, which can improve the performance stability of the product in complex vibration environment.

[0222] Example 10

[0223] Using the prepreg with damping rubber film obtained in Example 6, a simple four-layer printed circuit board sample was made according to the aforementioned printed circuit board preparation process.

[0224] The pretreatment of each layer of material, from top to bottom, is as follows:

[0225]

Top Layer

[0226]

Damping Adhesive Layer 1

[0227]

Inner Layer

[0228]

Damping Adhesive Layer 2

[0229] [Bottom Layer] A single-sided copper-clad FR4 core board is used, with dimensions of 150mm*150mm, board thickness of 0.5mm, copper thickness of 1oz, and the copper-clad side is the bottom layer;

[0230] Then, the circuit board samples were hot-pressed at 170℃ and 2.5MPa for 45 minutes, and a four-layer printed circuit board sample with a total thickness of about 2.0mm was produced through a hot lamination process.

[0231] Vibration tests were conducted on the entire printed circuit board sample according to the above method, and the total root mean square value of random vibration was measured. Compared with a PCB of the same thickness (the thickness of the damping rubber film is made up by the thickness of the prepreg) except that no damping rubber film was added, the total root mean square value of random vibration of the PCB of the present invention decreased by about 70%, indicating that the resonance amplification factor was reduced by more than half, which can improve the performance stability of the product in complex vibration environment.

[0232] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, shall still fall within the protection scope of the present invention.

[0233] In industrial applications, the prepreg or printed circuit board of this invention can be used in vibration-sensitive or high-reliability electronic devices, such as aerospace electronic components, automotive electronic control modules, communication equipment, and precision measuring devices. By directly introducing high-damping materials into the PCB structure, vibration resonance can be effectively suppressed, extending the service life of the circuit board and its components, and improving the overall product quality and market competitiveness.

Claims

1. A prepreg with a damping rubber film for use in printed circuit boards, characterized in that: The damping rubber film is stacked between two semi-cured sheets. The thickness of the damping rubber film is 0.05-0.3 mm. The damping rubber film is formed from a damping rubber composition with nitrile rubber as the main rubber component. The damping rubber composition also includes a vulcanizing agent, a plasticizer, a reinforcing filler, and an anti-aging agent. The acrylonitrile (ACN) content in the nitrile rubber is greater than 30% and less than 60% by weight, and the Mooney viscosity of the nitrile rubber is greater than 60 and less than 120. The vulcanizing agent is selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents. The plasticizer is selected from one or more of ester plasticizers and petroleum resins, wherein the ester plasticizer is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms. The anti-aging agent is selected from two or more of phenols, polydihydroquinolines, amines, and imidazoles, and the content of the anti-aging agent is between 36 parts by weight and 55 parts by weight per 100 parts by weight of the rubber component. The reinforcing filler is selected from one or more of graphite, carbon black, and silica, and the particle size of the reinforcing filler is 1-100 micrometers. The damping rubber film maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25℃ to 70℃.

2. The prepreg having a damped rubber film according to claim 1, wherein, The rubber component in the damping rubber composition is 40-90% by weight.

3. The prepreg with a damping rubber film as described in claim 1 or 2, wherein, The content of the vulcanizing agent in the damping rubber composition is 1-30 parts by weight per 100 parts by weight of rubber component.

4. The prepreg with a damping rubber film as described in claim 1 or 2, wherein, The plasticizer content in the damping rubber composition is 1-20 parts by weight per 100 parts by weight of the rubber component.

5. The prepreg with a damping rubber film as described in claim 1 or 2, wherein, The content of reinforcing filler in the damping rubber composition is 1-50 parts by weight per 100 parts by weight of rubber component.

6. A method for preparing a prepreg with a damping rubber film as described in any one of claims 1 to 5, comprising: The process of laminating a damping rubber film between two semi-cured sheets and performing the lamination at 10~25℃ and 0.1~1.5MPa pressure.

7. The preparation method according to claim 6, wherein the damping rubber film is obtained by hot-pressing and vulcanizing a pre-formed rubber film with a thickness of 0.05-0.3 mm after casting at 120-200℃ and 3-15 MPa.

8. A printed circuit board comprising one or more layers of a prepreg with a damping rubber film as described in any one of claims 1 to 5, or comprising one or more layers of a damping rubber film as described in any one of claims 1 to 5.

9. The printed circuit board of claim 8, wherein the resonant amplification factor is reduced by more than half compared to a printed circuit board comprising a prepreg of equal thickness.

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