Preparation method of high-toughness bismaleimide resin prepreg and composite material

Abstract

The invention relates to the technical field of bismaleimide resin, in particular to a preparation method of a high-toughness bismaleimide resin prepreg and a composite material, the high-toughness bismaleimide resin prepreg comprises a three-layer structure of a fiber layer, an interface buffer layer and a resin layer, and the thickness of the interface buffer layer is 0.1-30 [mu] m; the interface buffer layer is prepared from the following raw materials in parts by weight: 10 to 100 parts of toughening material, 100 parts of process modifier and 0.5 to 2.5 parts of coupling agent; the resin layer is prepared from the following raw materials in parts by weight: 40-70 parts of diphenylmethane bismaleimide resin, 50-80 parts of a modified diluent, 10-40 parts of thermoplastic resin, 1-30 parts of a toughening material, 1-30 parts of a curing agent, 5-15 parts of an accelerant and 10-50 parts of epoxy resin. Through special treatment on the resin-prepreg interface, the compression strength of the laminated board after impact can be remarkably improved, the performance is improved, and the technological process is simplified.

Description

Technical Field

[0001] The invention relates to the field of bismaleimide resins, and in particular to a method for preparing a high-toughness bismaleimide resin prepreg and a composite material. Background Art

[0002] With the rapid development of aerospace technology, the demand for high-performance composite materials is increasing. As an important component of composite materials, the performance of prepreg yarn directly affects the quality and performance of the final composite material. As a component of the prepreg yarn matrix, the epoxy resin system has its own viscosity that affects the viscosity of the prepreg yarn and the impregnation effect. The glass transition temperature of the epoxy resin system determines the use environment, etc. The performance of the epoxy resin system affects the performance of the prepreg yarn. Therefore, different epoxy resin systems need to be combined according to the use environment and requirements. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing a high-toughness bismaleimide resin prepreg and a composite material.

[0004] In a first aspect, the present invention provides a high-toughness bismaleimide resin prepreg, comprising a three-layer structure of a fiber layer, an interface buffer layer and a resin layer, wherein the thickness of the interface buffer layer is 0.1-30 μm;

[0005] The raw materials for preparing the interface buffer layer include, by weight:

[0006] 10-100 parts of toughening material, 100 parts of process modifier, 0.5-2.5 parts of coupling agent;

[0007] The raw materials for preparing the resin layer include:

[0008] 40-70 parts of diphenylmethane bismaleimide resin, 50-80 parts of modified diluent, 10-40 parts of thermoplastic resin, 1-30 parts of toughening material, 1-30 parts of curing agent, 5-15 parts of accelerator and 10-50 parts of epoxy resin.

[0009] In a second aspect, a method for preparing a composite material of a high-toughness bismaleimide resin prepreg is provided, comprising the following steps:

[0010] Step 1: 10-100 parts of the toughening material, 100 parts of the process modifier, and 0.5-2.5 parts of the coupling agent are prepared into a saturated solution by a solution impregnation method, and then the prefabricated yarn is coated and impregnated by a dry method or a wet method, and then prefabricated into a substrate A by heating it multiple times for standby use;

[0011] Step 2, heating 40-70 parts of the diphenylmethane bismaleimide resin and 50-80 parts of the modified diluent to 120-150 degrees Celsius by heating and mixing evenly, fully mixing for 10-40 minutes to form a uniform phase and then lowering the temperature to below 100 degrees Celsius, then adding 10-50 parts of the weighed epoxy resin and dispersing them evenly to form a substrate B, and then adding 1-30 parts of the toughening material, 10-40 parts of the thermoplastic resin, 1-30 parts of the curing agent, and 5-15 parts of the accelerator to the substrate B by multiple additions to form a substrate C for standby use;

[0012] Step 3: The substrate A and the substrate C are made into prepreg by hot melt process.

[0013] Preferably, the step 2 specifically includes:

[0014] The modified diluent is specifically one or more of allyl phenol, allyl bisphenol A, polyether sulfone and DDS;

[0015] The specific ratio of the diphenylmethane bismaleimide resin to the modified diluent is 1:(0.7-1) in molar ratio;

[0016] The toughening material is specifically a thermoplastic toughening material, polysulfone or polyetherketone, and the toughening material and the substrate B are used in a specific weight ratio of (0.3-0.5):1;

[0017] The diphenylmethane bismaleimide resin and the coupling agent are in a weight ratio of 100:(1-3).

[0018] Preferably, the step 2 specifically includes:

[0019] The curing agent is specifically one or more of a high temperature resistant benzoxazine resin and DDS.

[0020] Preferably, the step 2 specifically includes:

[0021] The specific method of adding the modified diluent is to gradually add the modified diluent during the process of heating to 120-150 degrees Celsius, and the modified diluent is kept warm for at least 23 minutes after heating to 120-150 degrees Celsius.

[0022] Preferably, the step 2 specifically includes:

[0023] When the temperature is lowered to below 100 degrees Celsius, mechanical stirring combined with natural cooling is used, wherein the mechanical stirring rate is 30-50 r / min;

[0024] The epoxy resin is added while stirring, wherein the stirring rate is 30-50r / min and the dispersion rate is 100-400r / min;

[0025] After 1-30 parts of the toughening material, 1-30 parts of the curing agent, and 5-15 parts of the accelerator are added to the substrate B, the substrate C is obtained by stirring at 20-50 r / min, adding in steps at a dispersion rate of 200-300 r / min, and then naturally cooling.

[0026] Preferably, the step 2 specifically includes:

[0027] The epoxy resin is a bisphenol A type multifunctional epoxy.

[0028] Preferably, the step 2 specifically includes:

[0029] The accelerator is an imidazole-type adduct, specifically one or two of 2-methylimidazole, 1-methylimidazole, dimethyltetraethylimidazole, etc.

[0030] Preferably, the step three specifically includes:

[0031] During the hot melt process of preparing the prepreg, the temperature is controlled at 30-70°C.

[0032] Preferably, the step 1 specifically includes:

[0033] When the toughening material is configured into the saturated solution, it needs to be heated to 70-100° C. in a solvent and then maintained for (1.0-1.5) h;

[0034] The coupling agent is specifically one or more of KH550, KH560, KH570 and lipids;

[0035] The process modifier is specifically one or more of acetone, dmf and allylphenol.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] This patent can significantly improve the post-impact compression strength of the laminate, improve performance, and simplify the process flow through special treatment of the resin-prepreg interface. The optimized resin ratio and interface can significantly shorten the curing time and cost of similar bismaleimide resin prepregs on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the prepreg structure of the present invention.

[0039] Figure 2 The figure is a schematic diagram of the process for preparing the composite material of the present invention. DETAILED DESCRIPTION

[0040] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0041] like Figure 1 A high-toughness bismaleimide resin prepreg shown includes a three-layer structure of a fiber layer, an interface buffer layer and a resin layer, wherein the thickness of the interface buffer layer is 0.1-30 μm;

[0042] By weight, the raw materials for preparing the interface buffer layer include:

[0043] 10-100 parts of toughening material, 100 parts of process modifier, 0.5-2.5 parts of coupling agent;

[0044] The raw materials for preparing the resin layer include:

[0045] 40-70 parts of diphenylmethane bismaleimide resin, 50-80 parts of modified diluent, 10-40 parts of thermoplastic resin, 1-30 parts of toughening material, 1-30 parts of curing agent, 5-15 parts of accelerator and 10-50 parts of epoxy resin.

[0046] Specifically, the raw materials for preparing the fiber layer include yarns.

[0047] like Figure 2 The method for preparing a composite material of a high-toughness bismaleimide resin prepreg comprises the following steps:

[0048] Step 1: 10-100 parts of toughening material, 100 parts of process modifier, and 0.5-2.5 parts of coupling agent are prepared into a saturated solution by solution impregnation method, and then the prefabricated yarn is coated and impregnated by dry method or wet method, and then prefabricated into substrate A by multiple heating and waiting;

[0049] Step 2, 40-70 parts of diphenylmethane bismaleimide resin and 50-80 parts of modified diluent are heated to 120-150 degrees Celsius by mixing evenly while heating, and after being fully mixed for 10-40 minutes, the temperature is lowered to below 100 degrees Celsius, and then 10-50 parts of epoxy resin are weighed and evenly dispersed to form substrate B, and then 1-30 parts of toughening material, 10-40 parts of thermoplastic resin, 1-30 parts of curing agent, and 5-15 parts of accelerator are added to substrate B by multiple additions to form substrate C for standby use;

[0050] Step 3: Prepare prepreg by hot-melt process using substrate A and substrate C.

[0051] Specifically, the toughening material is a combination of one or more of polyetherketoneketone, polyetherimide, polyarylethersulfone, polysulfone and polyester.

[0052] Specifically, the yarn is specifically T800 carbon fiber tow.

[0053] Specifically, step 2 includes:

[0054] The modified diluent is specifically one or more of allyl phenol, allyl bisphenol A, polyether sulfone and DDS;

[0055] The specific ratio of diphenylmethane bismaleimide resin to modified diluent is 1:(0.7-1) in molar ratio;

[0056] The toughening material is specifically a thermoplastic toughening material, polysulfone or polyetherketone, and the ratio of the toughening material to the base material B is specifically a weight ratio (0.3-0.5): 1;

[0057] The weight ratio of diphenylmethane bismaleimide resin to coupling agent is 100:(1-3).

[0058] Specifically, step 2 includes:

[0059] The curing agent is specifically one or more of a high temperature resistant benzoxazine resin and DDS.

[0060] Specifically, step 2 includes:

[0061] The specific method of adding the modified diluent is to gradually add it during the process of heating to 120-150 degrees Celsius, and the modified diluent is kept warm for at least 23 minutes after heating to 120-150 degrees Celsius.

[0062] Specifically, step 2 includes:

[0063] When the temperature is lowered to below 100 degrees Celsius, mechanical stirring is combined with natural cooling, wherein the mechanical stirring rate is 30-50r / min;

[0064] The epoxy resin is added while stirring, wherein the stirring rate is 30-50r / min and the dispersion rate is 100-400r / min;

[0065] After 1-30 parts of toughening material, 1-30 parts of curing agent and 5-15 parts of accelerator are added to substrate B, substrate C is obtained by naturally cooling after stirring at 20-50 r / min and adding in steps at a dispersion rate of 200-300 r / min.

[0066] Specifically, step 2 includes:

[0067] The epoxy resin is a bisphenol A type multifunctional epoxy.

[0068] Specifically, step 2 includes:

[0069] The accelerator is an imidazole-type adduct, specifically one or two of 2-methylimidazole, 1-methylimidazole, dimethyltetraethylimidazole and the like.

[0070] Specifically, step three includes:

[0071] During the hot melt process of preparing prepreg, the temperature is controlled at 30-70°C.

[0072] Specifically, step one includes:

[0073] When the toughening material is configured into a saturated solution, it needs to be heated to 70-100°C in the solvent and maintained for (1.0-1.5) hours;

[0074] The coupling agent is specifically one or more of KH550, KH560, KH570 and lipids;

[0075] The process modifier is specifically one or more of acetone, dmf and allylphenol.

[0076] It should be noted that the thickness of the prepreg prepared in step 3 was 0.1-30 μm when the performance parameters were verified by plate laying, as observed by scanning electron microscope.

[0077] Example 1

[0078] Step 1: After 10 parts by weight of polyaryletherketone, 100 parts by weight of dimethylamide and 1 part by weight of KH570 are heated and dissolved in an organic solution at 80°C, the T800 carbon fiber tow is completely impregnated by pultrusion and then dried and observed by a scanning electron microscope within a range of 3 μm for later use;

[0079] Step 2: Weigh 60 parts by weight of diphenylmethane bismaleimide resin, 45 parts by weight of o-diallyl bisphenol A, and 1.5 parts by weight of silane coupling agent KH570 and a lipid mixture, prepolymerize them at an oil bath temperature of 120-150 degrees Celsius for 10-40 minutes, lower the temperature to 90°C, add 30 parts by weight of E51 epoxy resin to make the resin matrix into a liquid with uniform color, finally weigh 10 parts by weight of polyarylethersulfone, polysulfone and polyester mixture, 20 parts by weight of allylphenol, 10 parts by weight of diaminodiphenylsulfone, and 10 parts by weight of a mixture of dimethylimidazole and dimethyltetraethylimidazole, add them into the system in sequence, mix well, and cool for standby use;

[0080] Step 3: The products of steps 1 and 2 are made into T800 prepreg through hot melt process for panel laying and performance parameter verification.

[0081] Embodiment 2

[0082] 60 parts by weight of diphenylmethane bismaleimide resin, 45 parts by weight of o-diallyl bisphenol A and 1.5 parts by weight of silane coupling agent KH570 were weighed and prepolymerized with a lipid mixture at an oil bath temperature of 120-150 degrees Celsius for 10-40 minutes. After the temperature was lowered to 90°C, 30 parts by weight of E51 epoxy resin were added to turn the resin matrix into a liquid with uniform color. Finally, 10 parts by weight of polyarylethersulfone, polysulfone and polyester mixture, 20 parts by weight of allylphenol, 10 parts by weight of diaminodiphenylsulfone, and 10 parts by weight of a mixture of dimethylimidazole 10 and dimethyltetraethylimidazole were weighed and added into the system in sequence. After mixing and cooling, the prepreg was made into T800 prepreg by hot melt process for panel laying and performance parameter verification.

[0083] Comparative Example 1

[0084] Weigh 60 parts by weight of diphenylmethane bismaleimide resin, heat the temperature to 90°C, add 30 parts by weight of E51 epoxy resin, mix well, weigh 10 parts by weight of polyarylethersulfone, polysulfone and polyester mixture, 20 parts by weight of allylphenol, 10 parts by weight of diaminodiphenylsulfone, and 10 parts by weight of a mixture of dimethylimidazole and dimethyltetraethylimidazole, and add them into the system in sequence. After mixing, cool and make it into T800 prepreg through a hot melt process for panel laying and verification of performance parameters.

[0085] The resin and prepreg planks in the above examples and comparative examples were cured using the same curing parameters, and their heat resistance and impact strength were tested respectively. The results are shown in the following table:

[0086]

[0087]

[0088] It can be concluded from the data in the table that in the comparative example, for the unmodified bismaleimide resin, under the same toughening material and curing material conditions as in the example, the glass transition temperature, impact strength and post-impact compression strength of the cured product are significantly lower than those after the fiber surface interface treatment;

[0089] The fiber surface of Example 2 which has not been treated is also lower than that of Example 1 which has been treated under the same modification conditions.

[0090] In summary, special treatment of the resin-prepreg interface can significantly improve the post-impact compressive strength of the laminate, improve performance, simplify the process flow, and the optimized resin ratio and interface can significantly shorten the curing time and cost of similar bismaleimide resin prepregs on the market.

[0091] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A high-toughness bismaleimide resin prepreg, characterized in that: It comprises a three-layer structure of a fiber layer, an interface buffer layer and a resin layer, wherein the thickness of the interface buffer layer is 0.1-30 μm; The raw materials for preparing the interface buffer layer include, by weight: 10-100 parts of toughening material, 100 parts of process modifier, 0.5-2.5 parts of coupling agent; The raw materials for preparing the resin layer include: 40-70 parts of diphenylmethane bismaleimide resin, 50-80 parts of modified diluent, 10-40 parts of thermoplastic resin, 1-30 parts of toughening material, 1-30 parts of curing agent, 5-15 parts of accelerator and 10-50 parts of epoxy resin.

2. A method for preparing a composite material of a high-toughness bismaleimide resin prepreg, used for preparing a high-toughness bismaleimide resin prepreg as claimed in claim 1, characterized in that: The following steps are involved: Step 1: 10-100 parts of the toughening material, 100 parts of the process modifier, and 0.5-2.5 parts of the coupling agent are prepared into a saturated solution by a solution impregnation method, and then the prefabricated yarn is coated and impregnated by a dry method or a wet method, and then prefabricated into a substrate A by heating it multiple times for standby use; Step 2, heating 40-70 parts of the diphenylmethane bismaleimide resin and 50-80 parts of the modified diluent to 120-150 degrees Celsius by heating and mixing evenly, fully mixing for 10-40 minutes to form a uniform phase and then lowering the temperature to below 100 degrees Celsius, then adding 10-50 parts of the weighed epoxy resin and dispersing them evenly to form a substrate B, and then adding 1-30 parts of the toughening material, 10-40 parts of the thermoplastic resin, 1-30 parts of the curing agent, and 5-15 parts of the accelerator to the substrate B by multiple additions to form a substrate C for standby use; Step 3: The substrate A and the substrate C are made into prepreg by hot melt process.

3. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: The modified diluent is specifically one or more of allyl phenol, allyl bisphenol A, polyether sulfone and DDS; The specific ratio of the diphenylmethane bismaleimide resin to the modified diluent is 1:(0.7-1) in molar ratio; The toughening material is specifically a thermoplastic toughening material, polysulfone or polyetherketone, and the toughening material and the substrate B are used in a specific weight ratio of (0.3-0.5):1; The diphenylmethane bismaleimide resin and the coupling agent are in a weight ratio of 100:(1-3).

4. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: The curing agent is specifically one or more of a high temperature resistant benzoxazine resin and DDS.

5. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: The modified diluent is specifically added in a stepwise manner during the temperature rise to 120-150 degrees Celsius, and the modified diluent is kept warm for at least 23 minutes after the temperature rises to 120-150 degrees Celsius.

6. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: When the temperature is lowered to below 100 degrees Celsius, mechanical stirring combined with natural cooling is used, wherein the mechanical stirring rate is 30-50 r / min; The epoxy resin is added while stirring, wherein the stirring rate is 30-50r / min and the dispersion rate is 100-400r / min; After 1-30 parts of the toughening material, 1-30 parts of the curing agent, and 5-15 parts of the accelerator are added to the substrate B, the substrate C is obtained by stirring at 20-50 r / min, adding in steps at a dispersion rate of 200-300 r / min, and then naturally cooling.

7. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: The epoxy resin is a bisphenol A type multifunctional epoxy.

8. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 2 specifically includes: The accelerator is an imidazole-type adduct, specifically one or two of 2-methylimidazole, 1-methylimidazole, dimethyltetraethylimidazole, etc.

9. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step three specifically includes: During the hot melt process of preparing the prepreg, the temperature is controlled at 30-70°C.

10. The method for preparing a composite material of a high-toughness bismaleimide resin prepreg according to claim 2, characterized in that: The step 1 specifically includes: When the toughening material is configured into the saturated solution, it needs to be heated to 70-100° C. in a solvent and then maintained for (1.0-1.5) h; The coupling agent is specifically one or more of KH550, KH560, KH570 and lipids; The process modifier is specifically one or more of acetone, dmf and allylphenol.

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