What is the prepreg?

The prepreg is a composition of resin matrix and reinforcement by impregnating continuous fiber or fabric with resin matrix under strictly controlled conditions.B ecause of its easy to use, consistent performance and high quality surface finish, it is becoming more and more common in the composite industry.

Classification

According to the physical state, the prepreg is divided into unidirectional prepreg, unidirectional fabric prepreg and fabric prepreg, and according to the resin matrix, the prepreg is divided into thermosetting resin prepreg and thermoplastic resin prepreg.

Thermosetting Resin Prepreg

It is more commonly used in the manufacture of prepreg composites. The main resin matrix used is epoxy resin. Other thermosetting resins are made into prepreg, including BMI and phenolic resin. Using thermosetting prepreg, thermosetting resin starts with liquid and is completely impregnated with fiber reinforced material. The excess resin is precisely removed from the reinforcement. At the same time, the epoxy resin undergoes partial curing, thus changing the state of the resin from liquid to solid. This is the so-called “stage B”. In stage B, the resin is partially cured and usually sticky. When the resin rises to a high temperature, it usually returns to the liquid briefly before it hardens completely. After curing, the thermosetting resin in stage b is now completely cross-linked.

Thermoplastic Resin Prepreg

It is the reinforcement of composite materials (glass fiber, carbon fiber, aramid, etc.), which has been pre-impregnated with thermoplastic resin. C ommon resins used for thermoplastic prepreg include PP,PET,PE,PPS and PEEK. Thermoplastic prepreg can be provided in the form of unidirectional tape or woven or stitched fabric. The main difference between thermosetting prepreg and thermoplastic prepreg is that thermoplastic prepreg is stable at room temperature and usually has no shelf life. This is the direct result of the difference between thermosetting resin and thermoplastic resin.

Product Characteristics

1. High strength and low density —- The strength of carbon fiber prepreg can reach 6-12 times that of steel, and the density is only 1/4 of steel.

2. Good plasticity —- Can be made into any shape according to the mold shape, easy to shape and easy to process.

3. Corrosion resistance and long life.

Preparation Method

There are two kinds of methods: dry method and wet method. Dry method can be divided into powder method and hot melt resin method (the latter is also called hot melt method). Powder prepreg refers to a kind of composite in which the resin powder is attached to the fiber and partially melted to form a discontinuous resin and the fiber is not fully impregnated by the resin. Compared with the composites made of dry prepreg and wet prepreg, the appearance of the former is better and the control precision of resin content in the material is higher than that of the wet prepreg.

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