阅读说明：本技术 一种非热压罐成型中温固化预浸料制备方法 (Preparation method of non-autoclave molding medium-temperature curing prepreg ) 是由 刘建 杨茂伟 付强 于 2019-07-26 设计创作，主要内容包括：本发明属于复合材料制备技术领域,涉及一种适用于非热压罐成型中温固化的预浸料制备方法。所述预浸料由树脂基体和纤维增强材料组成；所述树脂基体由树脂、固化剂、增韧剂,所述树脂的重量为预浸料总重量的35％～50％,预浸料制备方法包括以下步骤：首先配制树脂基体,树脂基体需满足特定的要求,之后对树脂基体进行加热,调节树脂基体粘度,并采用涂膜工艺将树脂基体制成树脂胶膜；最后将制备的树脂胶膜含浸到纤维增强材料上制备得到预浸料。降低成型后制件的空隙率,提高了制件的力学性能,极大地降低了制造成本,提高产品质量。(The invention belongs to the technical field of composite material preparation, and relates to a preparation method of prepreg suitable for non-autoclave molding and medium-temperature curing. The prepreg consists of a resin matrix and a fiber reinforced material; the resin matrix comprises resin, a curing agent and a toughening agent, the weight of the resin is 35-50% of the total weight of the prepreg, and the prepreg preparation method comprises the following steps: firstly, preparing a resin matrix which needs to meet specific requirements, then heating the resin matrix, adjusting the viscosity of the resin matrix, and preparing the resin matrix into a resin adhesive film by adopting a coating process; and finally, impregnating the prepared resin adhesive film on a fiber reinforced material to prepare the prepreg. The void ratio of the molded part is reduced, the mechanical property of the part is improved, the manufacturing cost is greatly reduced, and the product quality is improved.)

1. a preparation method of a non-autoclave molding medium-temperature curing prepreg is characterized by comprising the following steps: the prepreg consists of a resin matrix and a fiber reinforced material; the resin matrix comprises resin, a curing agent and a toughening agent, wherein the weight of the resin is 35-50% of the total weight of the prepreg, the weight of the curing agent is 1-6% of the total weight of the prepreg, the weight of the toughening agent is 1-6% of the total weight of the prepreg, and the preparation method of the prepreg comprises the following steps:

Firstly, preparing a resin matrix, wherein the resin matrix needs to have high viscosity of 5000 Pa.s-10000 Pa.s at room temperature, lower viscosity of 5 Pa.s-50 Pa.s at 65-85 ℃, longer gel time of 150-500 min and curing temperature of 1 Pa.s-5 Pa.s at 125-135 ℃,

secondly, heating the resin matrix, and preparing the resin matrix into a resin adhesive film by adopting a coating process when the viscosity of the resin matrix is adjusted to be 5-50 pas;

and thirdly, impregnating the prepared resin adhesive film on a fiber reinforced material to prepare the prepreg.

2. the prepreg production method according to claim 1, characterized in that: the resin comprises one or more of epoxy resin, polyester resin, phenolic resin and cyanate resin.

3. The prepreg production method according to claim 1, characterized in that: in the second step, the resin adhesive film is prepared by adjusting the film coating gap to be 0.1-0.6 mm at a film coating speed of 1-10 m/min to control the surface density of the adhesive film.

4. The prepreg production method according to claim 1, characterized in that: and in the third step, the impregnation temperature is controlled within the range of 60-100 ℃, the viscosity of the resin adhesive film is controlled within the range of 5-50 Pa.s, the impregnation speed is adjusted to be 1-10 m/min, and the impregnation degree of the dry fiber fabric is controlled by adjusting the gap between compression rollers to be 0.1-1 mm, so that the preparation of the prepreg is completed.

5. A prepreg production method according to claim 1 or 3, characterized in that: the resin adhesive film can be a single-sided adhesive film or a double-sided adhesive film.

6. The prepreg production method according to claim 1, characterized in that: the fiber reinforced material used for preparing the prepreg comprises one or more of ultrahigh molecular weight polyethylene fiber, quartz fiber, aramid fiber, polyimide fiber, glass fiber and carbon fiber.

7. The prepreg production method according to claim 1, characterized in that: the viscosity of the prepared resin matrix at 70-80 ℃ is 10-30 pas, and the gel time is 240-300 min.

8. The prepreg production method according to claim 1 or 6, characterized in that: the fiber reinforced material is quartz fiber.

Technical Field

The invention belongs to the technical field of composite material preparation, and relates to a preparation method of prepreg suitable for non-autoclave molding and medium-temperature curing.

Background

The advanced resin matrix composite material has the advantages of high specific strength, high specific modulus, corrosion resistance, fatigue resistance, designable performance and the like, and becomes an important material for aerospace structures. At present, an autoclave prepreg forming technology is mainly adopted for forming high-performance resin-based composite materials for aerospace, but the molding technology has the defects of high energy consumption, high auxiliary material cost, limited part size, long process and the like, and further popularization and application of the composite materials are limited. Furthermore, since the autoclave molding process typically removes gases and volatiles trapped between the prepreg layers by applying a greater molding pressure, the risk of core collapse and vacuum bag rupture is increased.

The non-autoclave molding process (out of autoclaves, OOA for short) can effectively overcome the defects of the autoclave molding process, particularly, the non-autoclave prepreg can be cured in an oven only by providing a vacuum pressure, and the process is a low-cost composite material manufacturing technology. Meanwhile, how to control the porosity of the composite material under a vacuum pressure to enable the mechanical property of the composite material to reach the autoclave curing level becomes the first challenge for developing a non-autoclave molding prepreg system.

The traditional autoclave process prepreg requires that resin completely soaks dry fibers, and in the curing process of the composite material, the high pressure effect of the autoclave can dissolve the entrapped air and other volatile matters in the paving layer into the resin, so that the void content is reduced. For the non-autoclave curing process, only one atmosphere of pressure is applied to the surface of a part to be manufactured in the curing process of the composite material, so that how to remove residual gas mixed between prepreg layers under one atmosphere of pressure is difficult to achieve, so that the void ratio of the composite material product is reduced, and the performance of the composite material is improved.

Disclosure of Invention

The invention aims to provide a prepreg preparation method for non-autoclave process molding, and the prepreg which is suitable for the non-autoclave process and has good manufacturability and mechanical property is obtained, so that the low-cost manufacturing of a high-performance composite material is realized.

the technical scheme is as follows: the prepreg is composed of a resin matrix and a fiber reinforced material, wherein the resin matrix is composed of epoxy resin, a curing agent and a toughening agent, the weight of the epoxy resin is 35% -50% of the total weight of the prepreg, the weight of the curing agent is 1% -6% of the total weight of the prepreg, the weight of the toughening agent is 1% -6% of the total weight of the prepreg, and the preparation method can be specifically adjusted according to the requirement of adhesive strength;

The preparation method comprises the following steps:

Step 1, preparing resin, wherein the resin has high viscosity of 5000 Pa.s-10000 Pa.s at room temperature, lower viscosity of 5 Pa.s-50 Pa.s at 65-85 ℃, longer gel time of 150-500 min and 1 Pa.s-5 Pa.s at curing temperature of 125-135 ℃, so that the resin is suitable for a non-autoclave prepreg curing process and the prepared prepreg has good manufacturability;

And 2, heating the resin, and preparing the resin into a single-sided or double-sided resin adhesive film by adopting a coating process when the viscosity of the resin is adjusted to be 5-50 pas. The preparation method is to adjust the film coating gap to be between 0.1mm and 0.6mm to control the surface density of the adhesive film at the film coating speed of between 1m/min and 10 m/min.

And 3, impregnating the prepared resin adhesive film into one side or the upper side and the lower side of the fiber fabric to prepare the prepreg. Controlling the impregnation temperature within the range of 60-100 ℃, ensuring the viscosity of the resin adhesive film to be 5-50 Pa.s, adjusting the impregnation speed to be 1-10 m/min, and controlling the impregnation degree of the dry fiber fabric by adjusting the compression roller gap to be 0.1-1 mm, thereby completing the preparation of the non-autoclave prepreg.

The prepared resin adhesive film can be a single-sided adhesive film or a double-sided adhesive film;

the resin used for preparing the prepreg comprises one or more of epoxy resin, polyester resin, phenolic resin and cyanate resin.

the reinforcing fiber used for preparing the prepreg comprises one or more of ultra-high molecular weight polyethylene fiber, quartz fiber, aramid fiber, polyimide fiber, glass fiber and carbon fiber.

The beneficial technical effects are as follows: the method for preparing the medium-temperature curing prepreg can be used for non-autoclave process molding. By improving the impregnation degree and the impregnation method of the resin adhesive film and the fiber fabric, the fiber air guide channel is constructed in the prepared prepreg, so that gas is easier to discharge in the curing process only under the atmospheric pressure vacuum condition, the void ratio of the molded part is reduced, the mechanical property of the molded part is improved, the manufacturing cost is greatly reduced, and the product quality is improved. The invention has good application value and economic benefit in the technical field of high-performance composite material manufacturing.

Drawings

FIG. 1 is a schematic cross-sectional view of a prepreg in a non-autoclave process.

Detailed Description

A prepreg preparation method for non-autoclave process molding comprises the following steps;

Firstly, preparing resin to ensure that the resin has higher viscosity of 5 Pa.s-50 Pa.s at the temperature of 65-85 ℃; meanwhile, the viscosity is 0.1 Pa.s-2 Pa.s at the high temperature of 125-135 ℃;

Secondly, adjusting the gel time of the resin to ensure that the resin has longer gel time of 150-500 min at 65-85 ℃ so as to ensure that the resin is suitable for a non-autoclave molding process and the prepared prepreg has longer room temperature storage period;

thirdly, heating the resin to the viscosity of 5-50 Pa.s, preparing the adhesive film by adopting a film coating process, and adjusting the film coating speed to be 1-10 m/min and the film coating gap to be 0.1-0.6 mm to prepare the adhesive film with the required surface density;

Fourthly, impregnating and compounding the resin adhesive film and the fiber fabric reinforcement: the impregnation temperature is adjusted to ensure that the viscosity of the resin is between 20 Pa.s and 100 Pa.s, the compression roller gap is controlled to be between 0.1mm and 1mm, the compounding speed is adjusted to be between 1m/min and 10m/min, and the weight of the resin is 35 to 50 percent of the total weight of the prepreg.

in the specific implementation process of the preparation method, a medium-temperature curing epoxy resin system is selected, the proportion of epoxy resin, a modifier, a toughening agent and a corresponding curing agent is adjusted, rheological properties and the gel time of the resin are researched, the viscosity of the resin at 70-80 ℃ is 10-30 Pa.s, the gel time is 240-300 min, the resin can slowly flow at a low temperature, and the gas can be discharged in enough time while partial dry fibers are reserved; the viscosity at 125-135 ℃ is 1-5 pas, the gel time is 3min-10 min to ensure that the resin can completely soak the dry fiber at the curing temperature and can be quickly cured. The prepreg adopts quartz fiber fabric as a reinforcement, and the surface density of the quartz fiber is 216g/m²The gel content of the resin is controlled to be 38 percent. The coating temperature is selected to be 80 ℃, the resin viscosity is 10Pa.s, the single-sided adhesive film is prepared by adopting a coating process, the coating speed is adjusted to be between 1m/min and 3m/min, and the coating gap is adjusted to be between 0.1mm and 0.15mm to control the surface density of the single-sided adhesive film. Impregnating the prepared single-sided adhesive film and quartz fibers, heating the adhesive film to adjust the viscosity of resin to 60Pa.s, adjusting the gap between compression rollers to be 0.30mm, compounding at the speed of 3m/min, and controlling the proportion of the thickness of the fibers impregnated by the resin adhesive film to the total thickness of the fibers to be 20-30%. FIG. 1 is a schematic cross-sectional view of a prepreg in a non autoclave process, from which the form of the resin impregnated fibers can be seen.