TWI863680B - Prepreg, laminates, and printed circuit board using the same - Google Patents

Abstract

A prepreg, laminates, and printed circuit board using the same is provided. The prepreg are formed by impregnating a base material into a heat-resistant resin composition. The heat-resistant resin composition includes bismaleimide resin, allyl-modified long-chain polymer resin and fluorine-containing maleimide compound. The fluorine-containing maleimide compound reacts with the allyl-modified long-chain polymer resin to form a network structure. The weight ratio of bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75.

Description

Prepregs, laminates and printed circuit boards

The present invention relates to a prepreg, a laminate and a printed circuit board, and in particular to a heat-resistant prepreg, a laminate and a printed circuit board.

In the fields of electronics, aerospace, etc., printed circuit boards are used in a variety of high-speed digital communication applications, and usually need to select materials with excellent electrical and mechanical properties and high heat resistance. The existing technology usually uses a laminate with a copper foil/dielectric layer/copper foil structure to make printed circuit boards, and the dielectric layer is mostly formed by a resin with poor heat resistance, which does not meet the requirements. In addition, if too much heat-resistant resin is added, it will affect the mechanical and electrical properties.

Therefore, how to improve the resin composition formula to take into account both high heat resistance and excellent mechanical and electrical properties to further form prepregs, laminates and printed circuit boards to overcome the above-mentioned defects has become one of the important issues that the industry wants to solve.

The technical problem to be solved by the present invention is to provide a prepreg sheet in view of the shortcomings of the prior art, which is formed by impregnating a substrate in a heat-resistant resin composition, wherein the heat-resistant resin composition includes: a bismaleimide resin, an allyl-modified long-chain polymer resin, and a fluorine-containing maleimide compound. The fluorine-containing maleimide compound reacts with the allyl-modified long-chain polymer resin to form a network structure. The weight ratio of bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75.

In one embodiment of the present invention, the substrate is glass fiber, metal fiber, liquid crystal polymer fiber, synthetic fiber or natural fiber.

In one embodiment of the present invention, the weight ratio of the bismaleimide to the allyl-modified long-chain polymer resin is 0.9:1.1~1.1:0.9.

In one embodiment of the present invention, the bismaleimide is m-phenylene bismaleimide, 4,4'-bismaleimide diphenylmethane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane or phenylmethane maleimide.

In one embodiment of the present invention, the weight ratio of the allyl-modified long-chain polymer resin, the bismaleimide and the fluorine-containing maleimide compound is 100:85:15.

In one embodiment of the present invention, the allyl-modified long-chain polymer resin is an acryl benzoxazine resin or an acryl phenolic resin.

In one embodiment of the present invention, the fluorine-containing maleimide compound has a structure of formula A:

In one embodiment of the present invention, the gel time of the heat-resistant resin composition is 340 seconds to 360 seconds.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a laminated plate, which includes the aforementioned prepreg; and a metal foil layer, wherein the metal foil layer is arranged on at least one surface of the prepreg.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a printed circuit board, which includes the aforementioned laminate.

One of the beneficial effects of the present invention is that the prepreg, laminate and printed circuit board provided by the present invention can provide a prepreg with excellent electrical properties, excellent heat resistance and low expansion coefficient through the technical scheme of "fluorine-containing maleimide compound, which reacts with the allyl-modified long-chain polymer resin to form a network structure" and "the weight ratio of the bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75".

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention. However, the detailed description provided is only for reference and explanation, and is not used to limit the present invention.

The following is a specific embodiment to illustrate the implementation of the "prepreg, laminate and printed circuit board" disclosed in the present invention. The technical personnel in this field can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. The following implementation will further explain the relevant technical content of the present invention, but the disclosed content is not used to limit the scope of protection of the present invention.

It should be understood that the term "or" used in this article may include any one or more combinations of the associated listed items as appropriate.

The present invention provides a heat-resistant resin composition, which includes: a bismaleimide resin, an allyl-modified long-chain polymer resin, and a fluorine-containing maleimide compound. The bismaleimide resin can be m-phenylene-bismaleimide, 4,4'-bismaleimidodiphenyl methane, bis(3-ethyl-5-methyl-4-maleimido phenyl)methane, or phenylmethane maleimide.

Specifically, the fluorine-containing maleimide compound can react with the allyl-modified long-chain polymer resin to form a network structure to provide high heat resistance and excellent mechanical and electrical properties. In one embodiment of the present invention, the fluorine-containing maleimide compound can have a structure of formula A:

Furthermore, in one embodiment of the present invention, the synthesis method of the fluorine-containing maleimide compound is to place 17.9 grams of 4-amino-2-fluorobenzotrifluoride (4-Amino-2-fluorobenzotrifluoride) produced by Merck and 150 grams of dimethylacetamide (DMAC) in a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube, and heat it to about 60° C. and stir it evenly to make it completely dissolved. Subsequently, while maintaining stirring, 10 grams of maleic anhydride are gradually added within 20 minutes, and the temperature of the synthetic solution is raised to 90° C., and then 1 gram of 5-ethyl-2-methylpyridine is added. The mixture was gradually heated to 140°C and reacted for 1 hour. The reaction formula is shown in the following reaction formula A to obtain the fluorine-containing maleimide compound BMI-F.

As above, after reacting at 140℃ for 1 hour, the temperature was lowered to room temperature, and 400g of methanol was added for precipitation. After washing with methanol three times and drying, the fluorinated maleic anhydride resin of formula A in this case was obtained.

On the other hand, the allyl-modified long-chain polymer resin of the present invention can be an allyl benzoxazine resin or an allyl phenolic resin. Specifically, the allyl-modified long-chain polymer resin of the present invention can be synthesized by the methods described in the following Synthesis Examples 1 to 5.

[Synthesis Example 1] Preparation of propenylbenzoxazine (BZ-A) resin

100 grams of BPA-type benzoxazine resin (BPA-BZ produced by Yuanhong) and 300 grams of toluene were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, a cooling tube, a dropping device, and a decompression recovery device to form a synthetic solution. 15 grams of potassium hydroxide (KOH) was added and the synthetic solution was heated to about 40°C and stirred evenly. While maintaining stirring, 38 grams of allyl chloride (Allyl Chloride) was gradually added to the synthetic solution within 20 minutes to react for 1 hour. At this time, the synthetic solution gradually increased in temperature to about 90°C, and the synthetic solution was heated and maintained at a temperature of about 90°C and reacted for 1 hour. Then, the allyl chloride was removed at 90°C and under reduced pressure at 90 mmHg. Then, heating and stirring were stopped, 300 g of pure water was added and the mixture was left to stand for about 20 minutes. After the synthetic solution was separated into two layers, the lower aqueous phase was removed and the solution was washed with water three times until the washed solution was neutral, thereby obtaining a toluene solution of 410 g of propylene grafted benzoxazine (BZ-A). The reaction formula is shown in the following reaction formula 1.

[Synthesis Example 2] Preparation of Propylene Phenolic Resin (PN-A) Resin

100 grams of phenolic resin (Phenolic Novolac produced by Changchun) and 300 grams of toluene were added to the reactor, and 15 grams of potassium hydroxide (KOH) were added. While maintaining stirring, 38 grams of allyl chloride were gradually added to the synthetic solution within 20 minutes to react for 1 hour. Allyl chloride was then removed at 90°C and under reduced pressure at 90 mmHg. Subsequently, heating and stirring were stopped, 300 grams of pure water were added and allowed to stand for about 20 minutes. After the synthetic solution was separated into two layers, the lower aqueous phase was removed and washed with water three times until the washed solution was neutral, thus obtaining 417 grams of propylene grafted phenolic (PN-A) resin toluene solution. The reaction formula is shown in the following reaction formula 2.

[Synthesis Example 3] Preparation of Propylene Phenolic Resin (Nath-A) Resin

100 g of naphthol aralkyl phenolic resin (SN-495 Nathpthlene phenolic Novolac produced by Nippon Steel) and 300 g of toluene were added to the reactor, and 15 g of potassium hydroxide (KOH) was added. While maintaining stirring, 38 g of allyl chloride was gradually added to the synthetic solution within 20 minutes and reacted for 1 hour. Allyl chloride was then removed at 90°C and under reduced pressure at 90 mmHg. Then, stop heating and stirring, add 300 grams of pure water and let it stand for about 20 minutes. After the synthetic solution is separated into two layers, remove the lower aqueous phase and repeat water washing three times until the washed solution is neutral, and obtain 421g of acrylic grafted phenolic (Nath-A) resin toluene solution. The reaction formula is shown in the following reaction formula 3.

[Synthesis Example 4] Preparation of Propylene Phenolic Resin (DCDPN-A) Resin

100 g of DCDP novolac resin (ERM-6105 produced by SONGWON, Korea) and 300 g of toluene were added to a reactor, and 15 g of potassium hydroxide (KOH) was added. While stirring, 38 g of allyl chloride was gradually added to the synthetic solution within 20 minutes and reacted for 1 hour. Allyl chloride was then removed at 90°C and under reduced pressure at 90 mmHg. Subsequently, heating and stirring were stopped, 300 g of pure water was added and allowed to stand for about 20 minutes. After the synthetic solution was separated into two layers, the lower aqueous phase was removed and washed with water three times until the washed solution was neutral, to obtain a toluene solution of 417 g of propylene-grafted DCDPN novolac resin (DCDPN-A). The reaction formula is shown in the following reaction formula 4.

[Synthesis Example 5] Preparation of bisphenol-type acrylphenol formaldehyde resin (BPN-A) resin

100 g of phenolic resin (4,40-diglycidyl biphenyl novolac resin (GPH-65) produced by DIC, Japan) and 300 g of toluene were added to a reactor, and 15 g of potassium hydroxide (KOH) was added. While maintaining stirring, 38 g of allyl chloride was gradually added to the synthetic solution over 20 minutes and reacted for 1 hour. Allyl chloride was then removed at 90°C and under reduced pressure at 90 mmHg. Then, stop heating and stirring, add 300 grams of pure water and let stand for about 20 minutes. After the synthetic solution is separated into two layers, remove the lower aqueous phase and repeat water washing three times until the washed solution is neutral, and obtain a toluene solution of 417g of propylene grafted biphenyl phenolic resin (BPN-A). The reaction formula is shown in the following reaction formula 5.

Furthermore, the preparation method of the heat-resistant resin composition of the present invention is described in the following Examples 1 to 9. The reaction formulas of Examples 1 to 9 are roughly as shown in the following Reaction Formula 6.

[Implementation Example 1]

100 g of the benzoxazine resin (BZ-A) of Synthesis Example 1 and 200 g of methyl ethyl ketone (MEK) were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube to form a synthetic solution, and the synthetic solution was heated to about 70°C and uniformly stirred to dissolve. While maintaining stirring, 85 grams of 4,4'-bismaleimidodiphenyl methane resin and 15 grams of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes. At this time, the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution. The obtained product was called BMBZ-1. The gelling time of BMBZ-1 was 346 seconds when tested at 200°C by a gelator.

[Example 2]

100 g of the benzoxazine resin (BZ-A) of Synthesis Example 1 and 200 g of butanone were added to a 1-liter four-necked separable reaction flask equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70° C. and uniformly stirred to dissolve. While maintaining stirring, 85 grams of Bis(3-ethyl-5-methyl-4-maleimido phenyl)methane and 15 grams of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes. At this time, the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution. The obtained product was called BMBZ-2. The gelling time of BMBZ-2 was 365 seconds when tested at 200°C by a gelator.

[Implementation Example 3]

100 g of the benzoxazine resin (BZ-A) of Synthesis Example 1 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of benzyl maleimide (BMI-2300) and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes. At this time, the temperature of the synthetic solution rose to about 110°C, and the synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, which was called BMBZ-3. When tested with a gelator at 200°C, the gel time of BMBZ-3 was 355 seconds.

[Implementation Example 4]

100 g of the acrylphenol resin (PN-A) of Synthesis Example 2 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of 4,4'-bismaleimide diphenylmethane and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes, at which time the temperature of the synthetic solution rose to about 110°C, and the synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, and the obtained product was called BMPN-1. When tested with a gelator at 200°C, the gelation time of BMPN-1 was 346 seconds.

[Implementation Example 5]

100 g of the acrylphenol resin (PN-A) of Synthesis Example 2 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane resin and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes, and the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, which was called BMPN-2. When tested with a gelator at 200°C, the gelation time of BMPN-2 was 346 seconds.

[Implementation Example 6]

100 g of the acrylphenol resin (PN-A) of Synthesis Example 2 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of benzyl maleimide (BMI-2300) and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes. At this time, the temperature of the synthetic solution rose to about 110°C, and the synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, and the obtained product was called BMPN-3. When tested with a gelator at 200°C, the gelation time of BMPN-3 was 346 seconds.

[Implementation Example 7]

100 g of the acrylphenol resin (Nath-A) of Synthesis Example 3 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane resin and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes, and the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, and the obtained product was called BMNa. When tested with a gelator at 200°C, the gel time of BMNa was 346 seconds.

[Implementation Example 8]

100 g of the acrylphenol formaldehyde resin (DCDPN-A) of Synthesis Example 4 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane resin and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes, and the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction is then stopped to obtain a brown, transparent, clear solution. The product is called BMDC. When tested with a gelator at 200°C, the gel time of BMDC is 346 seconds.

[Implementation Example 9]

100 g of the bisphenol-type acrylphenol resin (BPN-A) of Synthesis Example 5 and 200 g of butanone were added to a 1-liter four-necked separable reaction bottle equipped with a heating device, a thermometer, a stirrer, and a cooling tube device to form a synthetic solution, and the synthetic solution was heated to about 70°C and stirred evenly to dissolve. While maintaining stirring, 85 g of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane resin and 15 g of fluorinated bismaleimide resin BMI-F were gradually added to the synthetic solution within 20 minutes, and the temperature of the synthetic solution rose to about 110°C. The synthetic solution was heated and maintained at a temperature of about 110°C and reacted for 1 hour. The reaction was then stopped to obtain a brown transparent clear solution, and the obtained product was called BMBPN. When tested with a gelator at 200°C, the gel time of BMBPN was 346 seconds.

The compositions and gelling times of Examples 1 to 9 are shown in Table 1. In Table 1, BMI-1 is 4,4'-bismaleimidodiphenyl methane resin; BMI-2 is bis(3-ethyl-5-methyl-4-maleimido phenyl)methane; and BMI-3 is phenylmethane maleimide (BMI-2300) resin. BMI-1, BMI-2 and BMI-3 are all produced by ACR.

The heat-resistant resin composition of the present invention can be made into a varnish-like form by uniformly mixing the components of the resin composition, including BMI-modified benzoxazine, fillers, toughening agents, etc., with a homogenizer and dissolving or dispersing them in a solvent for subsequent processing. The solvent can be any inert solvent that can dissolve or disperse the components of the resin composition but does not react with the components. The solvents that can be used to dissolve or disperse the components of the resin composition include but are not limited to: toluene, γ-butyrolactone, methyl ethyl ketone, cyclohexanone, butanone, acetone, xylene, methyl isobutyl ketone, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrolidone (NMP). Each solvent can be used alone or in combination. There is no special restriction on the amount of solvent used. In principle, as long as the components of the resin composition can be uniformly dissolved or dispersed therein, it can be used. In a preferred embodiment of the present invention, a mixture of toluene, methyl ethyl ketone, and γ-butyrolactone is used as the solvent.

Furthermore, the resin composition is impregnated or coated on the substrate, and the impregnated or coated substrate is dried to obtain a prepreg. Specifically, after the substrate is impregnated or coated, it can be heated and dried at 175°C for 2 to 15 minutes to obtain a semi-cured prepreg.

In one embodiment, the substrate may be a woven fiber cloth or a non-woven fiber cloth. The woven fiber cloth may be woven from glass fiber, metal fiber, liquid crystal polymer fiber, synthetic fiber or natural fiber. The material of the glass fiber may be E-glass, R-glass, ECR glass, C-glass or Q-glass. The material of the liquid crystal polymer fiber may be fully aromatic polyamide, fully aromatic polyester or polyindole. The material of the synthetic fiber may be polyvinyl alcohol, polyester, polyacrylic acid or polytetrafluoroethylene. The material of the natural fiber may be cotton cloth, linen cloth and felt. The material of the non-woven fiber cloth may be polytetrafluoroethylene, quartz, alumina, aluminum nitride, glass material, liquid crystal polymer or any combination thereof. However, the present invention is not limited thereto. In a preferred embodiment of the present invention, the substrate is 2116 reinforced glass fiber cloth.

The present invention can also provide a laminate and a printed circuit board. The laminate is obtained by laminating the aforementioned prepreg and metal foil. For example, four prepregs are laminated, and a 0.5 ounce copper foil is laminated on each of the outermost layers on both sides to form a laminate, which is then placed in a hot press for high-temperature hot pressing and curing. In one embodiment, the aforementioned laminate is heated to 200°C to 220°C at a heating rate of 3.0°C/min, and at this temperature, hot pressed for 120 minutes at a full pressure of 15 kg/cm2 (initial pressure of 8 kg/cm2). After cooling to room temperature, a double-sided copper-clad laminate is produced, which can be used to manufacture printed circuit boards.

Furthermore, Table 2 shows the composition and properties of Examples E1 to E10 and Comparative Examples C1 to C3 of the heat-resistant resin composition of the present invention.

其中，ODA-BZ及Allyl-BZ為元鴻生產之苯並噁嗪樹脂；填料為矽比科生產之10um cut SiO2；CNE環氧樹脂為長春人造樹脂、長鏈型環氧樹脂為Huntsman PKFE；增韌劑為李長榮公司生產之苯乙烯共聚物(SEBS)；SPB-100為磷系耐燃劑；銅箔為南亞生產之H1 1/3 oz。

Among them, ODA-BZ and Allyl-BZ are benzoxazine resins produced by Yuan Hong; the filler is 10um cut SiO2 produced by Sibelco; CNE epoxy resin is Changchun Man-Made Resin, and the long-chain epoxy resin is Huntsman PKFE; the toughening agent is styrene copolymer (SEBS) produced by Lee Chang Jung Corporation; SPB-100 is a phosphorus-based flame retardant; and the copper foil is H1 1/3 oz produced by Nan Ya.

Next strength refers to the adhesion of metal foil to the laminated prepreg. Next strength test is to tear a 1/8 inch wide copper foil vertically from the board surface, and the strength of adhesion is expressed by the amount of force required.

The heat resistance test is to immerse the dried metal foil laminate in a 288°C solder bath for 100 seconds and repeat the process 3 times. If the appearance does not change, it means the heat resistance is good and is recorded as "○". If there are bubbles and bulges on the appearance, it means the heat resistance is poor and is recorded as "×".

Glass transition temperature (Tg) is measured using a Thermal Mechanical Analyzer (TMA) in accordance with IPC-TM-650 2.4.24.4.

The water absorption test is based on IPC-TM-650 2.6.2. The copper foil is completely etched off the test piece. The size is 10cm*10cm. The test piece is first baked at 105℃ for half an hour, placed in a drying oven to cool and weighed. Then the test piece is immersed in pure water at 23℃ for 24 hours, taken out, wiped dry, and weighed after standing. Subtract the weight of the test piece before and after treatment to calculate the moisture absorption degree of the test piece.

The dielectric constant (Dk) is measured according to the IPC-TM-650 2.5.5 test specification. The dielectric constant represents the electronic insulation properties of the produced film. The lower the value, the better the electronic insulation properties. The dielectric loss (Df) is measured according to the IPC-TM-650 2.5.5 test specification.

The X/Y axis thermal expansion coefficient (CTE) is measured according to the IPC-TM-650-2.4.24 test specification. The thermal mechanical analyzer (TMA) is used to measure the thermal expansion coefficient (CTE) of the sample under test at a temperature below Tg. The folding resistance-MIT (folding resistance test) test is measured according to the JIS P8115 specification, where R=1.0mm, 90 degree bending frequency 175 times/minute, load 250g, to measure the number of bending times that can be tolerated.

[Beneficial effects of the embodiment]

One of the beneficial effects of the present invention is that the prepreg, laminate and printed circuit board provided by the present invention can provide a prepreg with excellent electrical properties, excellent heat resistance and low expansion coefficient through the technical scheme of "fluorine-containing maleimide compound, which reacts with the allyl-modified long-chain polymer resin to form a network structure" and "the weight ratio of the bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75".

The prepreg of the present invention is coated with a heat-resistant resin, wherein the weight ratio of bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75, preferably 0.9:1.1~1.1:0.9, to provide a prepreg with excellent electrical properties, excellent heat resistance and low expansion coefficient.

Furthermore, the weight ratio of the allyl-modified long-chain polymer resin, dimaleimide and fluorine-containing maleimide compound is 100:85:15, which can make the allyl-modified long-chain polymer resin react to form a network structure more efficiently. Therefore, the thermosetting resin of the present invention is used to make the resin composition to impregnate the substrate, which can make the substrate have better folding resistance.

On the other hand, the heat-resistant resin composition of the present invention includes 15 to 25 parts by weight of epoxy resin, 10 to 20 parts by weight of benzoxazine resin, and 50 to 60 parts by weight of the thermosetting resin of Examples 1 to 9. When the content of the epoxy resin is less than 15 parts by weight, the toughness of the heat-resistant resin composition is poor, and when the content of the epoxy resin is greater than 25 parts by weight, the impact resistance of the cured product of the heat-resistant resin composition is deteriorated. When the content of the benzoxazine resin is less than 10 parts by weight, the moisture absorption rate of the heat-resistant resin composition is deteriorated, and when the content of the benzoxazine resin is greater than 20 parts by weight, the cured product of the heat-resistant resin composition becomes too brittle, resulting in poor processability. When the content of the thermosetting resin is less than 50 parts by weight, the heat resistance of the heat-resistant resin composition is poor. When the content of the thermosetting resin is greater than 60 parts by weight, the processing performance of the heat-resistant resin composition will be affected.

Preferably, the heat-resistant resin composition of the present invention comprises 18 to 22 parts by weight of epoxy resin, 13 to 16 parts by weight of benzoxazine resin and 53 to 56 parts by weight of the thermosetting resin of Examples 1 to 9. In a preferred embodiment of the present invention, the epoxy resin is composed of a long-chain epoxy resin and a CNE epoxy resin in a weight ratio of 1:3, and the benzoxazine resin is composed of Allyl-BZ and ODA-BZ in a weight ratio of 1:2, thereby obtaining a heat-resistant resin composition with good high-temperature insulation, arc resistance and tracking resistance. After hardening, the heat-resistant resin composition can obtain a material with a high cross-linking density and improved flexibility, and is more suitable for use in electronics, aerospace and other fields.

The above disclosed contents are only the preferred feasible embodiments of the present invention, and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the contents of the specification and drawings of the present invention are included in the scope of the patent application of the present invention.

Claims (10)

A prepreg is formed by impregnating a substrate into a heat-resistant resin composition, wherein the heat-resistant resin composition includes: a bismaleimide resin; an allyl-modified long-chain polymer resin; and a fluorine-containing maleimide compound, which reacts with the allyl-modified long-chain polymer resin to form a network structure: wherein the weight ratio of the bismaleimide to the allyl-modified long-chain polymer resin is 0.75:1.25~1.25:0.75. The prepreg as described in claim 1, wherein the substrate is glass fiber, metal fiber, synthetic fiber or natural fiber. The prepreg as described in claim 1, wherein the weight ratio of the bismaleimide to the allyl-modified long-chain polymer resin is 0.9:1.1~1.1:0.9. The prepreg sheet as claimed in claim 1, wherein the bismaleimide is m-phenylene bismaleimide, 4,4'-bismaleimide diphenylmethane, bis(3-ethyl-5-methyl-4-maleimidephenyl)methane or phenylmethane maleimide. The prepreg as described in claim 1, wherein the weight ratio of the allyl-modified long-chain polymer resin, the bismaleimide and the fluorine-containing maleimide compound is 100:85:15. The prepreg sheet as described in claim 1, wherein the allyl-modified long-chain polymer resin is an acryl benzoxazine resin or an acryl phenolic resin. The prepreg as claimed in claim 1, wherein the fluorine-containing maleimide compound has a structure of formula A:

Formula A. The prepreg as described in claim 1, wherein the gel time of the heat-resistant resin composition is 340 seconds to 360 seconds. A laminated plate, comprising: a prepreg sheet as described in claim 1; and a metal foil layer, the metal foil layer being disposed on at least one surface of the prepreg sheet. A printed circuit board comprising a laminate as described in claim 9.