Epoxy resin prepreg for rapid secondary curing and preparation method thereof

Abstract

The invention discloses a rapid secondary curing epoxy resin prepreg and a preparation method thereof. An epoxy resin composition comprises common epoxy resin, weather-resistant modified phenolic resin, flexible modified epoxy resin, a curing agent, a modified catalyst and toluene. According to the invention, the modified epoxy resin and the auxiliary agent are added according to the characteristics of the epoxy resin, the prepared epoxy resin prepreg can be quickly secondarily cured and is convenient for secondary mold processing and molding, the flame retardance of the prepreg after secondary molding reaches UL94V-0 level, and the prepreg has the advantages of high flexibility, dimensional stability, heat resistance and the like; the problem that in the prior art, good flexibility and rapid curing of a laminated board cannot be met at the same time is solved. The epoxy resin is subjected to segmented reaction, the modified resin is sequentially added in a segmented manner for reaction, the catalyst is added, cross-linking reaction of epoxy functional groups of the epoxy resin at different stages is improved, and the product has excellent performance and can quickly react at a special temperature stage.

Description

Technical Field

[0001] The invention belongs to the technical field of prepreg preparation, and more specifically, relates to a fast secondary-cured epoxy resin prepreg and a preparation method thereof. Background Art

[0002] Semi-cured sheet, also known as "PP sheet", is one of the main materials for producing laminates, mainly composed of reinforcing materials and adhesives. At present, glass fiber cloth is commonly used as a reinforcing material, and epoxy resin composition is used as an adhesive. Flexibility, heat resistance, alkali resistance and flame retardancy are important performance indicators of adhesives. Epoxy resin has shortcomings such as poor heat resistance and poor flexibility due to its own structure. Therefore, solving the above-mentioned problems of epoxy resin has become a research focus and hotspot in the field of electronic packaging. Secondly, the high-temperature curing time of conventional epoxy semi-cured sheets is relatively long, and it takes more than 30 minutes above 160°C, which is not convenient for rapid mold processing. Therefore, the development of an epoxy resin composition that can be quickly secondary cured has important application value. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these objects and other advantages of the present invention, a fast secondary-cured epoxy resin prepreg is provided, the epoxy resin prepreg comprising a substrate and an epoxy resin composition supported on the substrate;

[0005] The substrate comprises glass fiber cloth;

[0006] The epoxy resin composition is composed of the following components in parts by weight: 40-60 parts of common epoxy resin, 10-15 parts of weather-resistant modified phenolic resin, 5-10 parts of flexible modified epoxy resin, 8-14 parts of curing agent, 0.05-0.1 parts of modified catalyst and 5-15 parts of toluene.

[0007] Preferably, the common epoxy resin is DER383 resin; the weather-resistant modified phenolic resin is 8020 resin; and the flexible modified epoxy resin is 240A40 resin.

[0008] Preferably, the curing agent is 4,4-diaminodiphenyl sulfone.

[0009] Preferably, the modified catalyst is an imidazole catalyst.

[0010] The method for preparing a fast secondary-cured epoxy resin prepreg as described above comprises the following steps:

[0011] Step 1: Add the common epoxy resin and weather-resistant modified phenolic resin melted in a hot bath into the reactor and stir evenly, heat to the specified temperature, then add the curing agent and toluene, pressurize and heat for 20 to 30 minutes, drop the sample on a colorless glass plate for observation, and stop keeping warm when it is completely transparent;

[0012] Step 2: After the reaction kettle is cooled to a certain temperature, add the flexible modified epoxy resin, stir evenly, add the modified catalyst, continue stirring, take samples to test the gel time at 150°C, if the gel time is greater than 300s, add the modified catalyst until the gel time is 250±50s, and obtain the epoxy resin adhesive;

[0013] Step 3: adding cyclohexanone to adjust the viscosity of the epoxy resin adhesive obtained in step 2, applying glue with a vertical glue coating machine, heating and drying, and obtaining a fast secondary cured epoxy resin prepreg.

[0014] Preferably, in step 1, the specified temperature is 100-120°C.

[0015] Preferably, in step 1, the pressurized heating is: heating to 110-130° C. at a heating rate of 0.2-0.5° C. / min under a pressure of 0.15-0.5 MPa.

[0016] Preferably, in the step 2, the temperature of the reaction kettle is lowered to 40-60° C. and stirring is continued for 100-140 min.

[0017] Preferably, in step three, the viscosity is adjusted to 50±15s (20°C); the speed of glue coating is 50-150cm / min; the heating and drying temperature is 120-200°C, and the time is 2-10min; and the resin content of the fast secondary cured epoxy resin prepreg is 38-65%.

[0018] Application of a fast secondary-cured epoxy resin prepreg prepared by the preparation method as described above in a laminate.

[0019] The present invention includes at least the following beneficial effects: the present invention adds modified epoxy resin and auxiliary agents according to the characteristics of epoxy resin, and the prepared epoxy resin semi-cured sheet can be quickly re-cured, shortens the hot pressing time, is convenient for secondary processing and molding, and improves production efficiency. The flame retardancy of the semi-cured sheet after secondary molding reaches UL94V-0 level, and has the advantages of good flexibility, dimensional stability, heat resistance, etc., which solves the problem that the prior art cannot simultaneously meet the requirements of good flexibility and rapid curing of laminated boards; the present invention adopts a segmented reaction of epoxy resin, adds modified resin in segments and reacts in sequence, adds a catalyst, improves the cross-linking reaction of epoxy functional groups of epoxy resin at different stages, and allows the product to have excellent performance and can react rapidly at special temperature stages.

[0020] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0023] Example 1

[0024] A fast secondary curing epoxy resin prepreg comprises a glass fiber cloth and an epoxy resin composition, wherein the epoxy resin composition is composed of the following components in parts by weight: 50 parts of a common epoxy resin (DER383), 10 parts of a weather-resistant modified phenolic resin (8020 resin), 5 parts of a flexible modified epoxy resin (240A40), 8 parts of 4,4-diaminodiphenyl sulfone, 0.05 parts of 2-methylimidazole, and 5 parts of toluene;

[0025] The preparation method thereof comprises the following steps:

[0026] Step 1: Put the common epoxy resin and weather-resistant modified phenolic resin melted in a hot bath into the reaction kettle and stir evenly, heat to 110°C, then add 4,4-diaminodiphenyl sulfone and toluene, and heat to 120°C at a heating rate of 0.3°C / min under a pressure of 0.2MPa, keep warm for 30 minutes, take a sample and drop it on a colorless glass plate for observation, and stop keeping warm when it is completely transparent;

[0027] Step 2: After the reaction kettle is cooled to 50°C, add the flexible modified epoxy resin, stir evenly, add 2-methylimidazole, continue stirring for 120 minutes, take a sample to test the gel time at 150°C, add 2-methylimidazole until the gel time is 250s, and obtain an epoxy resin adhesive;

[0028] Step 3: Add cyclohexanone to adjust the viscosity of the epoxy resin adhesive obtained in step 2 to 50s (20°C), use a vertical glue coating machine to apply glue at a speed of 100cm / min, heat at 160°C for 3min, and obtain a fast secondary cured epoxy resin semi-cured sheet with a resin content of 45%.

[0029] Example 2

[0030] The epoxy resin composition of this embodiment is composed of the following components in parts by weight: 50 parts of ordinary epoxy resin (D ER383), 12 parts of weather-resistant modified phenolic resin (8020 resin), 8 parts of flexible modified epoxy resin (240A40), 10 parts of 4,4-diaminodiphenyl sulfone, 0.08 parts of 2-methylimidazole, and 10 parts of toluene; the remaining steps are the same as those in Example 1.

[0031] Example 3

[0032] The epoxy resin composition of this embodiment is composed of the following components in parts by weight: 50 parts of ordinary epoxy resin (D ER383), 15 parts of weather-resistant modified phenolic resin (8020 resin), 10 parts of flexible modified epoxy resin (240A40), 14 parts of 4,4-diaminodiphenyl sulfone, 0.1 parts of 2-methylimidazole, and 15 parts of toluene; the remaining steps are the same as those in Example 1.

[0033] According to IPC-TM-650, the performance of the fast secondary cured epoxy resin prepregs prepared in Examples 1 to 3 was tested, and four prepregs were stacked and hot pressed at 160°C and 2MPa to form a laminated board, and the performance test results are shown in Table 1. It can be seen that the epoxy resin prepreg prepared by the present invention can be rapidly secondary cured, and the curing time is 4 to 6 minutes, which can effectively shorten the pressing time to ≤7 minutes, and the obtained laminated board has excellent flame retardancy, flexibility, dimensional stability and heat resistance.

[0034] Table 1

[0035]

[0036] Comparative Example 1

[0037] An epoxy resin prepreg comprises a glass fiber cloth and an epoxy resin composition, wherein the epoxy resin composition consists of the following components in parts by weight: 55 parts of a common epoxy resin (DER383), 10 parts of a flexible modified epoxy resin (240A40), 8 parts of 4,4-diaminodiphenyl sulfone, 0.05 parts of 2-methylimidazole, and 5 parts of toluene, and the remaining methods are the same as those in Example 1.

[0038] Comparative Example 2

[0039] An epoxy resin prepreg comprises a glass fiber cloth and an epoxy resin composition, wherein the epoxy resin composition consists of the following components in parts by weight: 53 parts of a common epoxy resin (DER383), 12 parts of a weather-resistant modified phenolic resin (8020 resin), 8 parts of 4,4-diaminodiphenyl sulfone, 0.05 parts of 2-methylimidazole, and 5 parts of toluene, and the remaining methods are the same as those in Example 1.

[0040] Four epoxy resin prepregs prepared in Comparative Examples 1 and 2 were stacked and hot-pressed at 160° C. and 2 MPa to form laminated boards. The performance test results are shown in Table 2. The secondary curing time of the epoxy resin prepregs prepared in Comparative Examples 1 and 2 was greater than that of Examples 1 to 3, and the curing time was 15 to 30 min. The pressing time was correspondingly extended to > 20 min. In addition, the flexibility, heat resistance and dimensional stability of the epoxy resin prepregs prepared in Comparative Examples 1 and 2 were also reduced.

[0041] Table 2

[0042]

[0043] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A fast secondary curing epoxy resin prepreg, characterized in that: The epoxy resin prepreg comprises a substrate and an epoxy resin composition loaded on the substrate; The substrate is one or more of glass fiber, carbon fiber, and silicon carbide fiber; The epoxy resin composition is composed of the following components in parts by weight: 40-60 parts of common epoxy resin, 10-15 parts of weather-resistant modified phenolic resin, 5-10 parts of flexible modified epoxy resin, 8-14 parts of curing agent, 0.05-0.1 parts of modified catalyst and 5-15 parts of toluene.

2. A fast secondary curing epoxy resin prepreg according to claim 1, characterized in that: The common epoxy resin is DER383 resin; the weather-resistant modified phenolic resin is 8020 resin; and the flexible modified epoxy resin is 240A40 resin.

3. A fast secondary curing epoxy resin prepreg according to claim 1, characterized in that: The curing agent is 4,4-diaminodiphenyl sulfone.

4. A fast secondary curing epoxy resin prepreg as claimed in claim 1, characterized in that: The modified catalyst is an imidazole catalyst.

5. The method for preparing a fast secondary cured epoxy resin prepreg according to claim 1, characterized in that: The following steps are involved: Step 1: Add the common epoxy resin and weather-resistant modified phenolic resin melted in a hot bath into the reactor and stir evenly, heat to the specified temperature, then add the curing agent and toluene, pressurize and heat for 20 to 30 minutes, drop the sample on a colorless glass plate for observation, and stop keeping warm when it is completely transparent; Step 2: After the reaction kettle is cooled to a certain temperature, add the flexible modified epoxy resin, stir evenly, add the modified catalyst, continue stirring, take samples to test the gel time at 150°C, if the gel time is greater than 300s, add the modified catalyst until the gel time is 250±50s, and obtain the epoxy resin adhesive; Step 3: adding cyclohexanone to adjust the viscosity of the epoxy resin adhesive obtained in step 2, applying glue with a vertical glue coating machine, heating and drying, and obtaining a fast secondary cured epoxy resin prepreg.

6. The method for preparing a fast secondary cured epoxy resin prepreg according to claim 5, characterized in that: In the step 1, the specified temperature is 100-120°C.

7. The method for preparing a fast secondary cured epoxy resin prepreg according to claim 5, characterized in that: In the step 1, the pressurized heating is: heating to 110-130° C. at a heating rate of 0.2-0.5° C. / min under a pressure of 0.15-0.5 MPa.

8. The method for preparing a fast secondary cured epoxy resin prepreg according to claim 5, characterized in that: In the step 2, the temperature of the reaction kettle is lowered to 40-60° C. and stirring is continued for 100-140 minutes.

9. The method for preparing a fast secondary cured epoxy resin prepreg according to claim 5, characterized in that: In the step three, the viscosity is adjusted to 50±15s (20°C); the speed of glue coating is 50-150cm / min; the heating and drying temperature is 120-200°C, and the time is 2-10min; the resin content of the fast secondary cured epoxy resin prepreg is 38-65%.

10. Use of a fast secondary-cured epoxy resin prepreg prepared by the preparation method according to any one of claims 5 to 9 in the preparation of copper-clad boards or laminates.

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