Controlled-thermal-expansion layer system with very diverse uses, formed from composite of polymers and knitted fibrous materials, has adjustable thermal expansion in x, y and z layers

摘要

The coefficient of thermal expansion of the laminate in the x-direction, y-direction and z-direction is adjustable : The laminate comprises layer(s) of prepregs pressed together, containing a plastic matrix and a fibrous material. Thermal expansion coefficients in the x and y directions are about equal; that in the z direction equals that in the y or the x or the x and y directions. Differences are limited to 0-5 ppm/K. The thermal expansion coefficient in the cited directions is preferably greater than 50 ppm/K. The fibrous material is a knit. It has high expansibility in the directions cited. It comprises a fiber made of glass, ceramic, carbon, metal, aramid, plastic, natural fibers or polyimide. At least two differing knitted layers are included. All layers in the laminate so formed, have knitting aligned in the same x, y directions. Adjacent layers are turned through the same angle. The matrix is a reactive resin, thermoplastic, cross-linked or non-cross linked elastomer. The matrix contains natural polymers, synthetic polymers and modified natural materials or their combinations. The knit has a knitted-in pattern. This is for identification, decoration and/or marking. In a particular application, a layer of polycarbonate is applied to the data storage layer. Additional functions are incorporated in the knit. The corresponding laminate is also claimed.