一卡二卡不卡无码视屏-你懂的在线资源av-岛国视频无码在线-婷婷五月天综国产一二区精品

In recent years, domestic security protection boxes have developed rapidly. In the initial stage, they mainly supplied military and fire protection. They were mainly used in military and police. The current domestic competition is fierce, but the products themselves lack innovation and most of them imitate the safety box of the United States sent to the company. To a certain extent, there are certain patent issues, at least in the export of this piece is still very problematic.

        At present, the main materials of domestic safety protection boxes are mainly ABS plastics and modified PP engineering plastics, both of which are widely used. However, compared with the two, ABS plastics are relatively sensory, lack sufficient elasticity, and are brittle. Therefore, the protective performance is still inferior to that of modified PP engineering plastics. Modified PP engineering plastics improve the flame retardancy and strength. , impact resistance, toughness and other aspects of performance. Of course, the cost of PP material will be relatively high. The product itself does not have an absolute price advantage, but its wear-resistance, drop-resistance, and low-temperature resistance have been accepted by more people.