In the carbon fiber industry, the phrase "from raw materials to carbon fibers, the price changes from 1 to 3; processing carbon fiber into composite materials, the price can change from 3 to 10". It is not difficult to see that from carbon fiber to composite materials, the industrial chain is extended, and the added value added is more. Finally, the cost of carbon fiber in composite materials will drop to 20% to 30%.
Carbon fiber fabrics and prepregs are the intermediate links in the development of carbon fiber, and are the only way to connect production and application. The development of carbon fiber prepreg is imperative, and it is also an effective means to lengthen the industrial chain and increase the added value of carbon fiber. According to development experience, carbon fiber prepregs and fabrics are new high-performance composite materials, basic materials for defense military enterprises, and advanced alternative materials for future civil industries. The carbon fiber prepreg production line with a width of 1.2 meters introduced by GE can meet the needs of military industry and civil products.
Carbon fiber prepreg products have shown a new development trend in recent years:
1. The advantages of large tow carbon fiber prepreg in the industrial field are prominent. The unidirectional carbon fiber prepreg has a surface density of up to 600 g / m2. This type of heavy prepreg greatly improves the efficiency of the prepreg and subsequent placement process. It is widely used in the field of wind power blades and automobiles.
2. The prepreg of non-autoclave process (OOA, Out of Autoclave) has been vigorously developed. This molding process greatly reduces the time and cost of the subsequent curing of the prepreg. These new prepregs can use the lower-cost vacuum bagging method, advanced pultrusion method and hot molding method.
3. The appearance of different prepreg product forms. For chopped prepreg, an economical molding process can be used. Semi-preg material does not need to be fully wetted during the prepreg process. The fiber is completely infiltrated in the subsequent process.
4. Special prepreg for different applications. For example, in the automotive field, the requirements for short-time molding of parts are high. In order to meet the subsequent rapid prototyping process, it is necessary to develop rapid curing prepregs of less than 5 minutes.
5. For the production of the board, SparPregTM was developed, and it is possible to obtain a low-porosity laminate without the need for compaction and other exhaust fabrics; in the field of composite molds, various companies have also developed corresponding prepreg products.
6. Prepreg with structure and function. The carbon nanotubes or chopped carbon fibers are mixed into the resin, and then the carbon fiber tow or fabric is infiltrated to form a prepreg with a wave-absorbing function.
7. Pre-preg co-cured with other materials. The prepreg can be cured together with the infused resin, it can be molded and cured together with SMC, or it can be molded and cured with unidirectional prepreg (fabric prepreg) and SMC.
Compared with thermosetting prepregs, thermoplastic prepregs do not require cold storage and transportation. The subsequent molding process is efficient and convenient, the material has high toughness and good impact resistance, and is particularly recyclable. It is in line with energy saving and emission reduction green. Environmental protection trends. However, there are four major problems with thermoplastic prepregs: First, the high viscosity of thermoplastic resins makes it very difficult to infiltrate fibers; Second, there is no suitable low-cost, high-efficiency and quality-preserving prepreg preparation method And equipment; third, the molding temperature of high-performance thermoplastic resin is above 350 ℃, the molding process of prepreg and its composite materials is very difficult; fourth, the price of high-performance thermoplastic resin is too expensive compared with general thermosetting resin. Currently, thermoplastic prepregs with different resin mass fraction accuracy are obtained mainly through powder spraying, fiber blending, film rolling and other processes internationally to meet the needs of various molding applications.