Medium-temperature fast curing single-component epoxy resin system for prepreg and preparation method thereof

文档序号：501692 发布日期：2021-05-28 浏览：7次中文

阅读说明：本技术 预浸料用中温快速固化单组分环氧树脂体系及其制备方法 (Medium-temperature fast curing single-component epoxy resin system for prepreg and preparation method thereof ) 是由王隽王钧于 2021-01-06 设计创作，主要内容包括：本发明属于环氧树脂技术领域,具体涉及一种预浸料用中温快速固化单组分环氧树脂体系及其制备方法。本预浸料用中温快速固化单组分环氧树脂体系包括：制备组分A,即将环氧树脂基体加热搅拌；制备组分B,即通过含活泼N-H键的咪唑类化合物与三聚氯氰进行亲核取代反应,得到含三嗪环结构的咪唑类潜伏型固化剂；以及将组分A和组分B加热搅拌混合均匀,得到预浸料用单组分环氧树脂体系。(The invention belongs to the technical field of epoxy resin, and particularly relates to a medium-temperature fast curing single-component epoxy resin system for prepreg and a preparation method thereof. The medium-temperature fast curing single-component epoxy resin system for the prepreg comprises: preparing a component A, namely heating and stirring an epoxy resin matrix; preparing a component B, namely performing nucleophilic substitution reaction on an imidazole compound containing active N-H bonds and cyanuric chloride to obtain an imidazole latent curing agent containing a triazine ring structure; and heating, stirring and uniformly mixing the component A and the component B to obtain a single-component epoxy resin system for the prepreg.)

1. A method for preparing a single-component epoxy resin system for a prepreg, the method comprising:

preparing a component A, namely heating and stirring an epoxy resin matrix;

preparing a component B, namely performing nucleophilic substitution reaction on an imidazole compound containing active N-H bonds and cyanuric chloride to obtain an imidazole latent curing agent containing a triazine ring structure; and

and heating, stirring and uniformly mixing the component A and the component B to obtain the single-component epoxy resin system for the prepreg.

2. The production method according to claim 1,

the epoxy resin matrix comprises at least one of bisphenol A type glycidyl ether, novolac epoxy resin and glycidyl amine type epoxy resin;

the heating and stirring temperature of the epoxy resin matrix is 50-120 ℃.

3. The production method according to claim 1,

the molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is as follows:

wherein

R₁Is one of hydrogen, methyl, ethyl, phenyl or undecyl, R₂Is one of hydrogen, methyl or phenyl.

4. The production method according to claim 1,

the preparation component B comprises:

mixing imidazole compounds containing active N-H bonds, acid-binding agents and solvents uniformly;

dripping organic solution of cyanuric chloride under the dripping condition;

nucleophilic substitution reaction is carried out under the nucleophilic substitution condition, and an imidazole group and a triazine ring are constructed in one molecule, namely the imidazole latent curing agent containing the triazine ring structure.

5. The production method according to claim 4,

the dropping conditions comprise:

the dropping atmosphere is inert atmosphere or nitrogen atmosphere;

the dropping temperature is 0-70 ℃; and

stirring while dripping;

the nucleophilic substitution conditions are as follows:

the nucleophilic substitution atmosphere is inert atmosphere or nitrogen atmosphere;

the nucleophilic substitution temperature is 65-120 ℃; and

stirring and reacting for 2-8 h.

6. The production method according to claim 4,

the molar ratio of the imidazole compound containing active N-H bonds, cyanuric chloride and the acid-binding agent is (3-3.2) to 1 (3-3.2).

7. The production method according to claim 4,

the concentration of the cyanuric chloride organic solution is 0.5-1.0 mol/L;

the solvent comprises one or a combination of more of tetrahydrofuran, acetone, benzene, toluene, xylene, N-dimethylformamide or N, N-dimethylacetamide;

the acid-binding agent comprises one or more of sodium hydride, pyridine, triethylamine, sodium hydroxide, potassium hydroxide and sodium carbonate.

8. The production method according to claim 5,

the molecular formula of the imidazole compound containing active N-H bonds is

Wherein

R₁Is any one of hydrogen, phenyl and alkyl, R₂Is any one of hydrogen, phenyl and alkyl.

9. The production method according to claim 1,

the mass ratio of the component A to the component B is 100 (6-12), and the heating and stirring temperature of the component A and the component B is 50-70 ℃.

10. The single-component epoxy resin system for the prepreg is characterized by comprising the following raw materials:

component A according to claim 1 and component B according to claim 1.

Technical Field

The invention belongs to the technical field of epoxy resin, and particularly relates to a medium-temperature fast curing single-component epoxy resin system for prepreg and a preparation method thereof.

Background

The prepreg forming process is one of the most main forming methods of the composite material, and has the advantages of simple and convenient operation, excellent mechanical property of the product, stable quality, convenience for large-scale industrial production and the like. The epoxy resin has the advantages of good mechanical property, bonding property, chemical corrosion resistance, electrical property, dimensional stability and the like, and a single-component epoxy resin system prepared by mixing the epoxy resin with a latent curing agent is one of the most main matrix resins of the prepreg. However, the conventional one-component epoxy resin system mainly uses dicyandiamide as a latent curing agent, which has disadvantages of high curing temperature and long curing time.

Disclosure of Invention

The invention provides a medium-temperature fast curing single-component epoxy resin system for prepreg and a preparation method thereof.

In order to solve the technical problem, the invention provides a preparation method of a single-component epoxy resin system for a prepreg, which comprises the following steps: preparing a component A, namely heating and stirring an epoxy resin matrix; preparing a component B, namely performing nucleophilic substitution reaction on an imidazole compound containing active N-H bonds and cyanuric chloride to obtain an imidazole latent curing agent containing a triazine ring structure; and heating, stirring and uniformly mixing the component A and the component B to obtain the single-component epoxy resin system for the prepreg.

As a further improvement of the present invention, the epoxy resin matrix comprises at least one of bisphenol a type glycidyl ether, novolac epoxy resin, glycidyl amine type epoxy resin; the heating and stirring temperature of the epoxy resin matrix is 50-120 ℃.

As a further improvement of the present invention,

the molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is shown in the specification

Wherein R is₁Is one of hydrogen, methyl, ethyl, phenyl or undecyl, R₂Is one of hydrogen, methyl or phenyl.

As a further improvement of the present invention, the preparation component B comprises: mixing imidazole compounds containing active N-H bonds, acid-binding agents and solvents uniformly; dripping organic solution of cyanuric chloride under the dripping condition; nucleophilic substitution reaction is carried out under the nucleophilic substitution condition, and an imidazole group and a triazine ring are constructed in one molecule, namely the imidazole latent curing agent containing the triazine ring structure.

As a further improvement of the present invention, the dropping conditions include: the dropping atmosphere is inert atmosphere or nitrogen atmosphere; the dropping temperature is 0-70 ℃; and stirring while dripping; the nucleophilic substitution conditions are as follows: the nucleophilic substitution atmosphere is inert atmosphere or nitrogen atmosphere; the nucleophilic substitution temperature is 65-120 ℃; and stirring for reaction for 2-8 h.

As a further improvement of the invention, the molar ratio of the imidazole compound containing active N-H bonds, cyanuric chloride and the acid-binding agent is (3-3.2) to 1 (3-3.2).

As a further improvement of the invention, the concentration of the organic solution of cyanuric chloride is 0.5-1.0 mol/L; the solvent comprises one or a combination of more of tetrahydrofuran, acetone, benzene, toluene, xylene, N-dimethylformamide or N, N-dimethylacetamide; the acid-binding agent comprises one or more of sodium hydride, pyridine, triethylamine, sodium hydroxide, potassium hydroxide and sodium carbonate.

As a further improvement of the invention, the molecular formula of the imidazole compound containing active N-H bonds is

Wherein R is₁Is any one of hydrogen, phenyl and alkyl, R₂Is any one of hydrogen, phenyl and alkyl.

As a further improvement of the invention, the mass ratio of the component A to the component B is 100 (6-12), and the heating and stirring temperature of the component A and the component B is 50-70 ℃.

In a second aspect, the present invention also provides a one-component epoxy resin system for prepreg, comprising the following raw materials: component A as described previously and component B as described previously.

The invention has the beneficial effects that the single-component epoxy resin system for the prepreg and the preparation method thereof firstly heat and stir the epoxy resin matrix to form the component A; then, carrying out nucleophilic substitution reaction on an imidazole compound containing active N-H bonds and cyanuric chloride to obtain an imidazole latent curing agent containing a triazine ring structure as a component B; and finally, heating, stirring and uniformly mixing the component A and the component B to obtain a single-component epoxy resin system for the prepreg, wherein the single-component epoxy resin system has the characteristics of long storage period at room temperature and medium-temperature rapid curing.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a process for preparing a one-component epoxy resin system for a prepreg according to the present invention.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A first part: elucidating the specific technical scheme

Referring to fig. 1, the present invention provides a method for preparing a one-component epoxy resin system for a prepreg (i.e., a medium-temperature fast curing one-component epoxy resin system for a prepreg), comprising: preparing a component A, namely heating and stirring an epoxy resin matrix; preparing a component B, namely performing nucleophilic substitution reaction on an imidazole compound containing active N-H bonds and cyanuric chloride to obtain an imidazole latent curing agent containing a triazine ring structure; and heating, stirring and uniformly mixing the component A and the component B to obtain the single-component epoxy resin system for the prepreg.

Optionally, the epoxy resin matrix comprises at least one of bisphenol a type glycidyl ether, novolac epoxy resin and glycidyl amine type epoxy resin; the heating and stirring temperature of the epoxy resin matrix is 50-120 ℃.

Optionally, the single-component epoxy resin system for the prepreg comprises a component A and a component B, the mass ratio of the component A to the component B is 100 (6-12), and the heating and stirring temperature is 50-70 ℃.

Optionally, the molecular structural formula of the imidazole latent curing agent containing a triazine ring structure is as follows:

wherein R is₁Is one of hydrogen, methyl, ethyl, phenyl or undecyl, R₂Is one of hydrogen, methyl or phenyl.

As an alternative embodiment for the preparation of component B.

The preparation component B comprises: mixing imidazole compounds containing active N-H bonds, acid-binding agents and solvents uniformly to form mixed liquor; dripping organic solution of cyanuric chloride under the dripping condition; nucleophilic substitution reaction is carried out under the nucleophilic substitution condition, and an imidazole group and a triazine ring are constructed in one molecule, namely the imidazole latent curing agent containing the triazine ring structure.

Optionally, the dropping conditions include: the dropping atmosphere is inert atmosphere or nitrogen atmosphere; the dropping temperature is 0-70 ℃; and stirring while dropping.

Optionally, the nucleophilic substitution conditions are: the nucleophilic substitution atmosphere is inert atmosphere or nitrogen atmosphere; the nucleophilic substitution temperature is 65-120 ℃; and stirring for reaction for 2-8 h.

Optionally, the molar ratio of the imidazole compound containing active N-H bonds, cyanuric chloride and the acid-binding agent is (3-3.2) to 1 (3-3.2). The concentration of the cyanuric chloride organic solution is 0.5-1.0 mol/L; the solvent comprises one or a combination of more of tetrahydrofuran, acetone, benzene, toluene, xylene, N-dimethylformamide or N, N-dimethylacetamide; the acid-binding agent comprises one or more of sodium hydride, pyridine, triethylamine, sodium hydroxide, potassium hydroxide and sodium carbonate.

In the scheme, an imidazole compound containing an active N-H bond and cyanuric chloride are adopted to carry out nucleophilic substitution reaction to obtain the imidazole latent curing agent containing a triazine ring structure, and the synthetic route is as follows:

the specific preparation process of the imidazole latent curing agent containing the triazine ring structure comprises the following steps: mixing an imidazole compound containing active N-H bonds, an acid-binding agent and a solvent uniformly in a reaction kettle, and continuously introducing nitrogen; dropwise adding an organic solution of cyanuric chloride into the reaction kettle at the temperature of 0-70 ℃ under the conditions of nitrogen and stirring; after the dropwise addition is finished, stirring and reacting for 2-8h at the temperature of 65-120 ℃; after the reaction is finished, the imidazole latent curing agent containing the triazine ring structure is obtained through purification operations such as filtration, reduced pressure distillation, washing, drying and the like.

Optionally, the molecular formula of the imidazole compound containing active N-H bonds is

Wherein R is₁Is any one of hydrogen, phenyl and alkyl, R₂Is any one of hydrogen, phenyl and alkyl.

Further, the invention also provides a single-component epoxy resin system for the prepreg, which comprises the following raw materials: component A as described previously and component B as described previously.

The conventional imidazole curing agent has high curing activity at normal temperature, has short pot life after being mixed with epoxy resin, and cannot be stored for a long time as a single-component system. Compared with the prior art, the imidazole curing agent disclosed by the invention can initiate epoxy resin to carry out anionic chain polymerization, has the characteristic of medium-temperature rapid curing, and has the beneficial effects that:

(1) aiming at the technical problems that the curing activity of a common imidazole curing agent at normal temperature is high and the storage period of a single-component system formed by the common imidazole curing agent and epoxy resin is short, the invention passivates the normal-temperature curing activity of the imidazole curing agent by adopting a chemical modification method, overcomes the defect of short pot life of the imidazole curing agent, improves the latency and effectively improves the storage period of the epoxy resin single-component system.

(2) The single component system consisting of the modified imidazole curing agent and the epoxy resin can be rapidly cured under the condition of medium temperature.

A second part: some examples are given below

Example 1

Selecting an imidazole latent curing agent containing a triazine ring structure, wherein the molecular structural formula of the curing agent is as follows:

wherein R is₁And R₂Are all hydrogen.

The preparation method of the imidazole latent curing agent containing the triazine ring structure comprises the following specific steps:

1) adding 20.4g of imidazole and 30.3g of triethylamine into a three-neck flask containing 250ml of tetrahydrofuran, stirring at room temperature until reactants are uniformly mixed, and continuously introducing nitrogen; dissolving 18.45g of cyanuric chloride in 100ml of tetrahydrofuran, and dropwise adding cyanuric chloride/tetrahydrofuran solution into the three-necked flask through a constant-pressure dropping funnel under the conditions of room temperature, nitrogen and stirring;

2) after the dropwise addition of the cyanuric chloride/tetrahydrofuran solution is finished, heating the temperature in the three-mouth bottle to 75 ℃, and stirring for reaction for 3 hours; after the reaction is finished, distilling under reduced pressure to remove tetrahydrofuran, cooling, adding the obtained solid product into 300ml of distilled water, stirring and washing, then filtering, and drying a filter cake to obtain the imidazole latent curing agent (number: T-1) containing the triazine ring structure, wherein the imidazole latent curing agent is light yellow powder, and the yield is 96%.

Example 2

The molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is as follows:

wherein R is₁Is methyl and R₂Is hydrogen.

The preparation method of the imidazole latent curing agent containing the triazine ring structure comprises the following specific steps:

1) adding 2-methylimidazole 24.6g and triethylamine 30.3g into a three-neck flask containing tetrahydrofuran 200ml, stirring at 50 ℃ until the reactants are uniformly mixed, and continuously introducing nitrogen; dissolving 18.45g of cyanuric chloride in 100ml of tetrahydrofuran, and dropwise adding cyanuric chloride/tetrahydrofuran solution into a bottle through a constant-pressure dropping funnel under the conditions of 50 ℃, nitrogen and stirring;

2) after the dropwise addition of the cyanuric chloride/tetrahydrofuran solution is finished, heating the temperature in the three-mouth bottle to 75 ℃, and stirring for reaction for 4 hours; after the reaction is finished, the tetrahydrofuran is removed by reduced pressure distillation, after cooling, the product is added into 300ml of distilled water for stirring and washing, then filtration is carried out, and the imidazole latent curing agent (number: T-2) containing the triazine ring structure is obtained after drying the filter cake, and yellow powder with the yield of 94 percent is obtained.

Example 3

The molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is as follows:

wherein R is₁Is ethyl and R₂Is hydrogen.

The preparation method of the imidazole latent curing agent containing the triazine ring structure comprises the following specific steps:

1) adding 2-ethylimidazole 28.8g and triethylamine 30.3g into a three-neck flask containing 300ml of acetone, stirring at 35 ℃ until the reactants are uniformly mixed, and continuously introducing nitrogen; dissolving 18.45g of cyanuric chloride in 120ml of acetone, and dropwise adding cyanuric chloride/acetone solution into a bottle through a constant-pressure dropping funnel at the temperature of 35 ℃ under the conditions of nitrogen and stirring;

2) after the dropwise addition of the cyanuric chloride/tetrahydrofuran solution is finished, heating the temperature in the three-mouth bottle to 65 ℃, and stirring for reacting for 6 hours; after the reaction is finished, reduced pressure distillation is carried out to remove acetone, the product is added into 300ml of distilled water after cooling, stirring and washing are carried out, then filtration is carried out, and a filter cake is dried to obtain the imidazole latent curing agent (number: T-3) containing the triazine ring structure, wherein the imidazole latent curing agent is light yellow solid with the yield of 92%.

Example 4

The molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is as follows:

wherein R is₁Is phenyl and R₂Is hydrogen.

The preparation method of the imidazole latent curing agent containing the triazine ring structure comprises the following specific steps:

1) adding 43.2g of 2-phenylimidazole and 30.3g of triethylamine to a three-neck flask containing 300ml of tetrahydrofuran, stirring at 40 ℃ until the reactants are uniformly mixed, and continuously introducing nitrogen; dissolving 18.45g of cyanuric chloride in 100ml of tetrahydrofuran, and dropwise adding cyanuric chloride/tetrahydrofuran solution into a bottle through a constant-pressure dropping funnel under the conditions of 40 ℃, nitrogen and stirring;

2) after the dropwise addition of the cyanuric chloride/tetrahydrofuran solution is finished, heating the temperature in the three-mouth bottle to 80 ℃, and stirring for reaction for 4 hours; after the reaction is finished, cooling to room temperature, filtering, taking filtrate, and distilling the filtrate under reduced pressure to remove tetrahydrofuran to obtain the imidazole latent curing agent (number: T-4) containing the triazine ring structure, wherein the yield is 95 percent.

Example 5

The molecular structural formula of the imidazole latent curing agent containing the triazine ring structure is as follows:

wherein R is₁Is ethyl and R₂Is methyl.

The preparation method of the imidazole latent curing agent containing the triazine ring structure comprises the following specific steps:

1) adding 2g of ethyl-4-methylimidazole and 30.3g of triethylamine into a three-neck flask containing 250ml of tetrahydrofuran, stirring at 50 ℃ until the reactants are uniformly mixed, and continuously introducing nitrogen; dissolving 18.45g of cyanuric chloride in 100ml of tetrahydrofuran, and dropwise adding cyanuric chloride/tetrahydrofuran solution into a bottle through a constant-pressure dropping funnel under the conditions of 50 ℃, nitrogen and stirring;

2) after the dropwise addition of the cyanuric chloride/tetrahydrofuran solution is finished, heating the temperature in the three-mouth bottle to 75 ℃, and stirring for reaction for 4 hours; after the reaction is finished, cooling to room temperature, filtering, taking filtrate, and distilling the filtrate under reduced pressure to remove tetrahydrofuran to obtain the imidazole latent curing agent (number: T-5) containing the triazine ring structure, wherein the yellow solid is obtained with the yield of 90%.

Example 6