澳门二十四小时线路中心检测(中国)有限公司

Plastic lenses instead of glass lenses, with light weight, not easy to break, convenient molding processing, easy coloring and other advantages, it should be noted that acrylic lenses need acrylic extrusion plate vacuum coating made of acrylic mirror, rather than acrylic pouring plate, pouring acrylic plate can not be made of acrylic mirror, Pouring acrylic plate is methyl methenate monomer (MMA) polymerization, extrusion acrylic is polymethyl methacrylate (PMMA) acrylic lenses are single-sided mirror, double-sided mirror, rubber mirror, paper mirror, half lens, etc., extrusion of acrylic plate particle raw materials, Tongplus equipment heating melting, and then extrusion sheet flattening process, then acrylic extrusion plate why deformation? Why do acrylic lenses deform? Related to its substrate, so extrusion acrylic plate to electroplated acrylic mirror need to pay attention to the following process:

1. Acrylic contains polar side methyl group, with obvious moisture absorption, water absorption rate is generally 0.3-0.4%, the acrylic sheet must be dried before forming, drying conditions are 80℃-85℃ drying 4-5h.

2. Acrylic has effective and obvious non-Newtonian fluid characteristics in the temperature range of molding processing, and the melt viscosity will decrease significantly with the increase of shear rate, and the melt viscosity is also sensitive to temperature changes. Therefore, for the molding process of polymethyl methacrylate, increasing the molding pressure and temperature can significantly reduce the melt viscosity and obtain better fluidity.

3. The temperature at which acrylic begins to flow is about 160 ° C, and the temperature at which it begins to decompose is higher than 270 ° C, with a wide processing temperature range.

4. Acrylic melt viscosity is higher, cooling rate is faster, the product is easy to produce internal stress, so the molding process conditions control requirements are strict, the product also needs to be post-processed after molding.

5. Acrylic is an amorphous polymer, the shrinkage rate and its range of change are small, generally about 0.5%-0.8%, which is conducive to forming plastic parts with high dimensional accuracy.