Solvent-free epoxy resin system suitable for continuous forming process for spaceflight and preparation method of solvent-free epoxy resin system

Abstract

The invention discloses a spaceflight solvent-free epoxy resin system suitable for a continuous forming process as well as a preparation method and application of the spaceflight solvent-free epoxy resin system. The epoxy resin system is prepared from raw materials including epoxy resin, a modifier and a curing agent, wherein the epoxy resin is selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin and phenolic aldehyde type epoxy resin. The environment-friendly solvent-free resin system is obtained by mixing the epoxy resin with the specific modifier and adding the curing agent, compared with an existing epoxy resin system, the solvent is removed, the resin toughness and the interface bonding force are improved, and the resin can be used for a continuous forming process, preparation of composite stringer structural parts for spaceflight and the like; and a resin-based composite material with good mechanical properties can be prepared from the composite material and a fiber reinforced material.

Description

Technical Field

[0001] The invention relates to a solvent-free epoxy resin system for aerospace use suitable for a continuous molding process and a preparation method thereof. Background Art

[0002] With the development of aerospace technology, aircraft use a higher proportion of fiber composite components to replace traditional metal components to reduce structural weight.

[0003] Epoxy resin is widely used in the field of aerospace composite materials due to its advantages such as high temperature resistance, good process compatibility and good mechanical properties. It has become the most practical type of material for spacecraft.

[0004] The continuous molding process refers to the composite material molding process that continuously inputs raw materials, impregnates-compounds, molds-cures, demoulds, cuts, and finally obtains the finished product. Due to the continuity of production, the equipment has the advantages of convenient process control, low labor intensity, low pollution, good working environment, high production efficiency, low cost, and stable product quality. It is an important method for low-cost composite materials. The application of its molded products involves many fields such as aviation, electrical, construction, industrial equipment, transportation, and marine engineering.

[0005] Therefore, it is of great significance to study solvent-free epoxy resin systems for continuous molding processes. Summary of the invention

[0006] In view of the above analysis, the present invention aims to provide a solvent-free epoxy resin system for aerospace use suitable for a continuous molding process and a preparation method thereof; the epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin.

[0007] The purpose of the present invention is mainly achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a solvent-free epoxy resin system for aerospace use suitable for a continuous molding process, wherein the components of the resin system and their mass fractions are as follows:

[0009] Epoxy resin 20-70 parts;

[0010] 10-50 parts of thermoplastic resin;

[0011] Curing agent 10-40 parts.

[0012] As an embodiment, the epoxy resin system comprises the following raw materials in weight ratio:

[0013] Epoxy resin 30-60 parts;

[0014] 20-40 parts of thermoplastic resin;

[0015] 20-30 parts of curing agent.

[0016] As an embodiment, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and novolac epoxy resin.

[0017] As an embodiment, the thermoplastic resin is at least one of polypropylene, polyetherimide, polysulfone, polyetherketone, and polyamide.

[0018] As an embodiment, the thermoplastic resin is selected from polyetherimide and polyamide. During preparation, polyetherimide and polyamide are added in batches.

[0019] As an embodiment, the curing agent is any one of m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone.

[0020] As an embodiment, the epoxy resin system can be fully cured at 180°C.

[0021] In a second aspect, the present invention provides a method for preparing the aforementioned epoxy resin system, the method comprising the following steps:

[0022] S1, mixing the epoxy resin and the thermoplastic resin A to obtain a uniform blending system;

[0023] S2, mixing the thermoplastic resin B with the above blending system to obtain a uniform blending system;

[0024] S3, mixing the curing agent with the above blending system to obtain a uniform blending system.

[0025] As an embodiment, the thermoplastic resin A is polyetherimide; and the thermoplastic resin B is polyamide.

[0026] As an embodiment, the mass ratio of the thermoplastic resin A to the thermoplastic resin B is 1-2:1.

[0027] As an embodiment, in step S1, the epoxy resin is heated and mixed with the thermoplastic resin A; preferably, the mixing is carried out by stirring, and the heating temperature is 120 to 160° C. and the heating time is 1 to 6 hours.

[0028] As an embodiment, in step S2, the blending system is heated and mixed with the thermoplastic resin; preferably, the mixing is carried out by stirring, and the heating temperature is 50 to 100° C. and the heating time is 0.5 to 2 hr.

[0029] As an embodiment, in step S3, the blending system is heated and mixed with the curing agent; preferably, the mixing is carried out by stirring, and the heating temperature is 50 to 100° C. and the heating time is 0.5 to 2 hr.

[0030] In a third aspect, the use of the epoxy resin system of the present invention in the preparation of composite material structural parts by continuous molding process also falls within the protection scope of the present invention.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention uses a thermoplastic resin as a modifier to prepare a resin system with an epoxy resin. The epoxy resin system has a high glass transition temperature and a low viscosity at room temperature, and the mechanical properties of the obtained cured product are good. The epoxy resin system can be directly used in a continuous molding process, and the use temperature is comparable to that of existing resin systems used for winding or lamination.

[0033] (2) The epoxy resin system obtained in the present invention can prepare a composite material without adding a solvent, which simplifies the process. At the same time, not adding a solvent is more environmentally friendly and avoids the influence of the presence of the solvent on the performance of the obtained composite material;

[0034] (3) The preparation process of the epoxy resin system and epoxy resin-based composite material of the present invention is simple, the continuous molding process is suitable for industrial large-scale production, and the composite material can be made at low cost. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0036] The technical solution of the present invention is further described in detail below through specific embodiments.

[0037] Example 1

[0038] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 150°C, and stir and mix evenly with 15g of polyetherimide at a stirring speed of 3000r / min for 2hr to obtain a mixture; cool to 90°C, add 10g of polyamide to the mixture, stir evenly at a stirring speed of 1000r / min for 30min, cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0039] Example 2

[0040] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 150°C, and stir and mix evenly with 12g of polyetherimide at a stirring speed of 3000r / min for 2hr to obtain a mixture; cool to 90°C, add 10g of polyamide to the mixture, stir evenly at a stirring speed of 1000r / min for 30min, cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0041] Example 3

[0042] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 150°C, and stir and mix them evenly with 10g of polyetherimide at a stirring speed of 3000r / min for 2hr to obtain a mixture; cool to 90°C, add 10g of polyamide to the mixture, stir evenly at a stirring speed of 1000r / min for 30min, cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0043] Example 4

[0044] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 150°C, and stir and mix evenly with 10g of polyetherimide at a stirring speed of 3000r / min for 2hr to obtain a mixture; cool to 90°C, add 15g of polyamide to the mixture, stir evenly at a stirring speed of 1000r / min for 30min, cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0045] Example 5

[0046] Take 40g of bisphenol A epoxy resin and 20g of bisphenol F epoxy resin, heat to 150°C, and stir and mix evenly with 15g of polyetherimide at a stirring speed of 3000r / min for 2hr to obtain a mixture; cool to 90°C, add 10g of polyamide to the mixture, stir evenly at a stirring speed of 1000r / min for 30min, cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0047] Comparative Example 1

[0048] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min and a stirring time of 30min to obtain an epoxy resin system, and store it for later use.

[0049] Comparative Example 2

[0050] Take 50g of bisphenol A epoxy resin and 10g of bisphenol F epoxy resin, heat to 130°C, and stir and mix evenly with 15g of polyetherimide and 10g of polyamide at a stirring speed of 3000r / min for 3hr to obtain a mixture; cool to 70°C, add 25g of diaminodiphenylmethane to the mixture, stir evenly at a stirring speed of 500r / min for 30min to obtain an epoxy resin system, and store for later use.

[0051] Effect verification

[0052] The viscosity and thermal properties of the epoxy resin systems obtained in Examples 1-5 and the resin systems obtained in Comparative Examples 1 and 2 were tested. The epoxy resin systems obtained in Examples 1-5 and the epoxy resin systems obtained in Comparative Examples 1 and 2 were prepared with T800 grade carbon fiber to prepare prepregs. The epoxy resin systems obtained in Examples 1-5 were used to prepare hot melt prepregs. The epoxy resin systems obtained in Comparative Examples 1 and 2 were used to prepare wet prepregs. The epoxy resin content (mass) in the prepregs was 33%, and the carbon fiber content (mass) was 67%. The prepregs were then used to prepare composite unidirectional boards for curing. The curing process was as follows: heating to 120° C. and keeping warm for 1 h, continuing to heat to 150° C. and keeping warm for 1 h, continuing to heat to 180° C. and keeping warm for 3 h. The mechanical properties of the cured products were tested. The testing method was based on GB / T 3354 and JC / T 773. The test results of the tensile strength, tensile modulus, and interlaminar shear strength are shown in Table 1.

[0053] Table 1. Performance test results of Examples 1-5 and Comparative Examples 1 and 2

[0054]

[0055]

[0056] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

[0057] The present invention has many specific application paths, and the above is only a preferred embodiment of the present invention. It should be pointed out that the above embodiments are only used to illustrate the present invention, and are not used to limit the protection scope of the present invention. For those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A solvent-free epoxy resin system for aerospace use suitable for continuous molding process, characterized in that: The components of the resin system and their mass fractions are as follows: Epoxy resin 20-70 parts; 10-50 parts of thermoplastic resin; Curing agent 10-40 parts.

2. The epoxy resin system according to claim 1, characterized in that The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

3. The epoxy resin system according to claim 1, characterized in that The thermoplastic resin is at least one of polypropylene, polyetherimide, polysulfone, polyetherketone and polyamide.

4. The epoxy resin system according to claim 1, characterized in that The thermoplastic resin is selected from polyetherimide and polyamide.

5. The epoxy resin system according to claim 1, characterized in that The curing agent is any one of m-phenylenediamine, diaminodiphenylmethane and diaminodiphenyl sulfone.

6. The epoxy resin system according to any one of claims 1 to 5, characterized in that The epoxy resin system can be completely cured at 180°C.

7. A method for preparing the epoxy resin system according to claim 1, characterized in that: The method comprises the following steps: S1, mixing the epoxy resin and the thermoplastic resin A to obtain a uniform blending system; S2, mixing the thermoplastic resin B with the above blending system to obtain a uniform blending system; S3, mixing the curing agent with the above blending system to obtain a uniform blending system.

8. The method for preparing the epoxy resin system according to claim 7, characterized in that: It also includes at least one of the following technical features: A. The thermoplastic resin A is polyetherimide; the thermoplastic resin B is polyamide; B. The mass ratio of the thermoplastic resin A to the thermoplastic resin B is 1-2:1; C. In step S1, the epoxy resin is heated and mixed with the thermoplastic resin A; the mixture is mixed by stirring, the heating temperature is 120 to 160° C., and the heating time is 1 to 6 hours; D. In step S2, the blending system is heated and mixed with the thermoplastic resin B; the mixing is carried out by stirring, the heating temperature is 50-100° C., and the heating time is 0.5-2 hr.

9. The method for preparing the epoxy resin system according to claim 7, characterized in that: In step S3, the blended system is heated and mixed with the curing agent; the mixing is carried out by stirring, the heating temperature is 50 to 100° C., and the heating time is 0.5 to 2 hours.

10. Use of the epoxy resin system according to claim 1 in preparing composite material structural parts by continuous molding process.

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