阅读说明：本技术 一种环氧树脂组合物、制备方法及其在热熔预浸料中的应用 (Epoxy resin composition, preparation method and application of epoxy resin composition in hot-melt prepreg ) 是由 刘含洋 于宗芝 马壮 王志勇 许峰 于 2019-12-26 设计创作，主要内容包括：本发明创造涉及一种环氧树脂组合物、制备方法及其在热熔预浸料中的应用,根据复合材料对固化温度、反应活性、工艺性和外观特性的要求,设计中温固化反应平缓的热熔环氧树脂的主体树脂及各个组分的比例,将主体环氧树脂、热塑性树脂、固化剂和促进剂,在一定条件下制备得到满足使用要求的环氧树脂组合物；然采用上述环氧树脂体系进行热熔胶膜的涂制,然后与增强纤维或织物进行复合得到热熔预浸料,采用该热熔环氧树脂制备的复合材料产品的表面外观饱满度和无孔洞。(The invention relates to an epoxy resin composition, a preparation method and application thereof in hot-melt prepreg, wherein according to the requirements of a composite material on curing temperature, reactivity, manufacturability and appearance characteristics, the proportion of a main body resin and each component of the hot-melt epoxy resin with moderate curing reaction at medium temperature is designed, and the main body epoxy resin, a thermoplastic resin, a curing agent and an accelerator are prepared under certain conditions to obtain the epoxy resin composition meeting the use requirements; then the epoxy resin system is adopted to coat the hot melt adhesive film, and then the hot melt adhesive film is compounded with the reinforced fiber or fabric to obtain the hot melt prepreg, and the surface appearance plumpness and the non-porous holes of the composite material product prepared by adopting the hot melt epoxy resin are realized.)

1. An epoxy resin composition characterized by: comprises the following components in percentage by mass:

74-92% of main body epoxy resin, 4-16% of thermoplastic resin, 2.3-8.6% of curing agent and 0.8-4.4% of accelerator;

the sum of the mass percentages of the components is 100 percent.

2. The epoxy resin composition according to claim 1, characterized in that: the host epoxy resin is a mixture of a low viscosity epoxy resin and a multifunctional epoxy resin.

3. The epoxy resin composition according to claim 2, characterized in that: the low-viscosity epoxy resin is one or the combination of bisphenol A glycidyl ether and bisphenol F glycidyl ether.

4. The epoxy resin composition according to claim 2, characterized in that: the multifunctional epoxy resin is one of glycidyl amine, phenolic epoxy resin and multifunctional glycidyl ester alicyclic epoxy resin or the combination of the glycidyl amine, the phenolic epoxy resin and the multifunctional glycidyl ester alicyclic epoxy resin.

5. The epoxy resin composition according to claim 1, characterized in that: the thermoplastic resin is one or the combination of polyvinyl formal, polyvinyl butyral and polyether sulfone.

6. The epoxy resin composition according to claim 1, characterized in that: the curing agent is one or the combination of dicyandiamide or modified dicyandiamide.

7. The epoxy resin composition according to claim 1, characterized in that: the accelerator is one or a combination of IA and IB; wherein, the chemical structural formulas of IA and IB are as follows:

8. the epoxy resin composition according to claim 7, characterized in that: the accelerator is preferably IA: the mass ratio of the IB composition is 1: 0.2-1: 1.0.

9. The process for producing an epoxy resin composition according to claims 1 to 8, wherein: the method comprises the following steps:

(1) dissolving multifunctional epoxy resin in the main epoxy resin and thermoplastic resin at the temperature of 100-150 ℃, and stirring for 30-120min at the heat preservation state until the materials are transparent to obtain a component A;

(2) adding the low-viscosity epoxy resin in the main epoxy resin, a curing agent and an accelerant in proportion, premixing, and grinding for 20-40min by using three-roll grinding equipment to obtain a component B;

(3) blending the component A in the component (1) and the component B in the component (2) at 60-90 ℃ for 10-40min to obtain the medium-temperature curing low-heat-release hot-melt epoxy resin composition.

10. A hot-melt prepreg characterized by using the epoxy resin composition according to any one of claims 1 to 9 as a resin matrix.

11. A hot melt prepreg characterized in that the prepreg manufacturing method comprises: a process of preparing a hot melt prepreg by coating the epoxy resin composition according to any one of claims 1 to 9 as a resin matrix to prepare a hot melt adhesive film and then compounding the hot melt adhesive film with a reinforcing fiber or fabric; wherein, the percentage mass content of the resin matrix is 30-40%.

Technical Field

The invention belongs to the technical field of manufacturing of hot-melt prepregs for structural composite materials, and particularly relates to an epoxy resin composition, a preparation method and application of the epoxy resin composition in the hot-melt prepregs.

Background

The resin-based composite material has been widely applied in the fields of aerospace, rail transit and the like due to the characteristics of light weight and high strength, in recent years, large-size and ultra-thick composite material components are more and more extensive, for example, the local thickness of a hydrogen transportation composite material tank body reaches 210mm, and the large shell and the variable-thickness structural part provide more rigorous requirements on resin matrix and forming process requirements, such as relatively mild curing process but curing at 130 ℃, no holes on the surface of a formed product, no additional spraying and the like.

Most of the existing medium-temperature curing systems are latent resin systems, 1-dimethyl-3-phenylurea is mostly adopted as an accelerator, the latent curing agent is rapidly excited at the temperature of 90-130 ℃, relatively large heat is released by reaction, a plurality of heat preservation steps are required to be manually arranged when a large-scale large-thickness composite material is formed, and the consistency of the product quality cannot be guaranteed. And the appearance quality of the composite material product manufactured by the prior resin system often has tiny cavities, a subsequent spraying procedure is needed, and the risk of peeling off at any time exists because the interface combination of the coating system and the composite material is poor.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art and providing a medium temperature curing low exothermic epoxy resin composition.

Another object of the present invention is to provide a method for preparing a medium-temperature curing low-exothermic hot-melt epoxy resin composition.

It is still another object of the present invention to provide a hot melt prepreg comprising the hot melt epoxy resin composition.

The above purpose of the invention is mainly realized by the following technical scheme:

the technical scheme of the invention is as follows: according to the requirements of the composite material on curing temperature, reactivity, manufacturability and appearance characteristics, the proportion of the main body resin and each component of the hot-melt epoxy resin with mild medium-temperature curing reaction is designed, and the hot-melt epoxy resin meeting the use requirement is prepared from the main body epoxy resin, the thermoplastic resin, the curing agent and the accelerator under certain conditions. The epoxy resin system is adopted to coat the hot melt adhesive film, and then the hot melt adhesive film is compounded with the reinforced fiber or the fabric to obtain the hot melt prepreg.

The specific method of the invention is as follows:

(1) dissolving multifunctional epoxy resin in the main epoxy resin and thermoplastic resin at the temperature of 100-150 ℃, and stirring for 30-120min at the heat preservation state until the materials are transparent to obtain a component A;

(2) adding the low-viscosity epoxy resin in the main epoxy resin, a curing agent and an accelerant in proportion, premixing, and grinding for 20-40min by using three-roll grinding equipment to obtain a component B;

(3) blending the component A in the component (1) and the component B in the component (2) at 60-90 ℃ for 10-40min to obtain the medium-temperature curing low-heat-release hot-melt epoxy resin composition.

Specifically, the mass percentages of the main body epoxy resin, the thermoplastic resin, the curing agent and the accelerator are respectively 74% -92%: 4% -16%: 2.3% -8.6%: 0.8 to 4.4 percent, and the sum of the percentage contents of the components is 100 percent. When the components are mixed according to the proportion, the resin system can be ensured to be cured smoothly and completely in a medium temperature range, and the surface of a composite material product prepared by the resin is ensured to have no holes, no spraying and the like.

Wherein the main epoxy resin is a mixture of a low-viscosity epoxy resin and a multifunctional epoxy resin, and preferably, the mass ratio of the low-viscosity epoxy resin to the multifunctional epoxy resin is 10:90-90: 10;

the low-viscosity epoxy resin is one or a combination of bisphenol A glycidyl ether (DYD128, Yueyang petrochemical resin factory) and bisphenol F glycidyl ether (830s, tin-free resin factory);

the multifunctional epoxy resin is one or the combination of glycidyl amine (AG-80, available on the market), novolac epoxy resin (638s, available on the market), multifunctional glycidyl ester alicyclic epoxy resin (TDE-85, available on the market);

the thermoplastic resin is thermoplastic plastic which can be dissolved in epoxy resin, preferably one or a combination of more of polyvinyl formal, polyvinyl butyral and polyether sulfone, and the thermoplastic resin can ensure that the appearance of a subsequent composite material product is smooth and has no holes;

the curing agent is one or the combination of dicyandiamide (Dicy, available in the market) or modified dicyandiamide (HT2833, available in the market);

the accelerator is a composition having the following chemical structures IA (Ecure20, commercially available) and IB (UR800, commercially available), preferably IA: the mass ratio of the IB composition is 1: 0.2-1: 1.0, so that the hot-melt epoxy resin system can be cured in a medium-temperature range, and the reaction releases heat smoothly due to a special chemical structure.

The hot-melt epoxy resin composition is used as a resin matrix to coat a hot-melt adhesive film, and then the hot-melt adhesive film is compounded with reinforcing fibers or fabrics to prepare the hot-melt prepreg. Wherein the percentage mass content of the resin matrix in the hot-melt prepreg is 30-40%.

The application of the medium-temperature cured hot-melt epoxy resin composition and the hot-melt prepreg prepared by the method in the preparation of resin matrix composite materials also belongs to the protection scope of the invention.

The beneficial effects created by the invention are as follows:

(1) the hot-melt epoxy resin composition provided by the invention adopts two accelerators of aromatic urea (IA) and alicyclic urea (IB) to be mixed, wherein the IA aromatic urea contains an electron-withdrawing induction effect of halogen atoms, so that the catalytic activity is reduced compared with that of 1, 1-dimethyl-3-phenylurea in the presence of dicyandiamide; IB is alicyclic urea, when used as a dicyandiamide catalyst, the curing is smoother, more storage periods can be given to prepreg, the technical problems that the resin system can be cured at 90-130 ℃, the reaction heat release is low, the curing is gentle and difficult to combine are solved, and finally the medium-temperature cured low-heat-release hot-melt epoxy resin system is obtained.

(2) The hot-melt epoxy resin composition provided by the invention is dissolved and modified by adopting specific thermoplastic resin, has good laminating property at room temperature, and the surface appearance plumpness and no pores of a composite material product prepared by adopting the hot-melt epoxy resin composition.

(3) The hot-melt epoxy resin composition and the prepreg thereof provided by the invention are already applied to large-scale super-size composite material products, and the surface of the product can meet the index requirement without secondary spraying.

Detailed Description

It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.