聚甲醛塑料，俗称赛钢，为结晶性热可塑性塑料，具明显熔点165~175℃，性质Zui接近金属。
优点 1、具高机械强度和刚性
2、Zui高的疲劳强度
3、环境抵抗性、耐有机溶剂性佳
4、耐反覆冲击性强
5、广泛的使用温度范围(-40℃~120℃)
6、良好的电气性质
7、复原性良好
8、具自已润滑性、耐磨性良好
9、尺寸安定性优
缺点 1、加工过程若长时间高温下易起热分解
2、无自熄性
3、抗酸性差
4、成形收缩率大
用途 电子电器：洗衣机、果汁机零件、定时器组件
汽 车： 车把零件、电动窗零件
工业零件：机械零件、齿轮、把手、玩具、螺杆
'It was somewhere here,' she said. 'I know I could still hearthe sound of the spring when I found thehollow under the bush. Ah -there's the bush!'
It certainly was a great bush, green and spiky14 outside,with a few yellow blooms on it still. Under itwas a big hollowplace, where the ground was soft andfine, scattered15 with dry old prickles.
The main trunk - for it was almost a trunk that supported the bigbush - was not quite in the middle,so there was a good bit of room.Julian caught hold of the branches that hid the hollow, usingafolded sheet of brown paper to hold them by, for the bush was veryprickly.