The prepreg is a composition in which a resin matrix and a reinforcement are formed by impregnating a continuous fiber or fabric under a strictly controlled condition with a resin matrix.

Classification：

According to the physical state, the prepreg can be divided into unidirectional prepreg, unidirectional fabric prepreg and fabric prepreg. According to the resin matrix, the prepreg is divided into thermosetting resin preg and thermoplastic resin preg. According to different reinforcing materials, it is divided into carbon fiber (fabric) prepreg, glass fiber (fabric) preg, aramid fiber (fabric) preg. According to the fiber length, it is divided into the short fiber (below 4176mm) prepreg, long fiber (1217mm) preg and continuous fiber preg. Divided by different curing temperature, curing temperature (120 ℃) presoak material, high temperature (180 ℃) in curing materials as well as the curing temperature over 200 ℃ presoak material, etc.

The preparation methods of prepreg include a dry method and a wet method. Dry method and powder method and hot – melt resin method (the latter is also known as a hot – melt method). Powder prepreg refers to the resin powder attached to the fiber, after partial melting, forming a resin discontinuous, fiber is not fully soaked by the resin of a complex. Compared with the composites made of dry prepreg and wet prepreg, the former has a better appearance and higher control precision of resin content. As for the advanced aviation composite materials, they often show that the wet-heat stability of the hot-melt composite materials is better than that of the solution composite materials: the mechanical properties (such as bending modulus and strength, laminar shear strength, etc.) of the former is better than that of the solution composite materials: the mechanical properties (such as bending modulus and strength, laminar shear strength, etc.) of the former is better than that of the solution composite materials.

Technical indicators

The state and chemical properties of the resin in the prepreg should be in accordance with the specific requirements of the product object, such as the degree of polymerization or polycondensation, molecular weight and its distribution, gel time, and the area of the pressurized section. The viscosity and playability and repairability of the prepreg are included. The rheological properties and outflow of the resin during the curing process should meet the requirements for use. The surface of the prepreg should be smooth, hairless and shiny. The thickness tolerance of the prepreg should be less than that of the intestine. The deviation of the resin content in the prepreg is not greater than that of the soil intestine when the fiber linear density deviation is in the afternoon, and the fiber unit area weight deviation is in the intestine. In prepregs, the degree of fiber collimation must not exceed eight in length.

The edge line should not deviate from the length by more than the visible gap and overlap. The non-particulate resin fiber should be free of buckling, collusion and significant deflagration of the prepreg. The volatile content is usually not more than 2%.

usual format

Common specifications of prepreg according to the fiber content per unit area are: C020, C030, C050, C075, C100, C125, C150, C175, C200, etc.; according to the resin content is divided into 25%, 33%, 37%, 40% and so on.