POM LD755旭化成

POM LD755旭化成，LD755是一种聚甲醛（POM）共聚物产品，低粘度、高刚度、高流动性， 密度:1.52 g/cm3 吸水率:0.2 % 成型收缩率:1.5 % 缺口冲击强度:29 硬度:80 热变形温度:130 ℃

物理性能 额定值 单位制 测试方法 比重 1.52 g/cm³ ASTM D792, ISO 1183 熔流率（熔体流动速率） (190°C/2.16 kg) 25 g/10 min ISO 1133 收缩率 - 流动 1.4 到 1.6 % 内部方法 吸水率 (23°C, 24 hr, 50% RH) 0.20 % ASTM D570 硬度 额定值 单位制 测试方法 洛氏硬度 ASTM D785    M 级 70 ASTM D785    R 级 115 ASTM D785 机械性能 额定值 单位制 测试方法 拉伸模量 3500 MPa ISO 527-2 拉伸应力    屈服 53.0 MPa ISO 527-2    -- 51.0 MPa ASTM D638 伸长率    断裂 8.0 % ASTM D638    断裂 10 % ISO 527-2 弯曲模量    -- 3390 MPa ASTM D790    -- 3400 MPa ISO 178 弯曲强度 86.0 MPa ASTM D790 冲击性能 额定值 单位制 测试方法 简支梁缺口冲击强度 3.0 kJ/m² ISO 179 悬壁梁缺口冲击强度 32 J/m ASTM D256 热性能 额定值 单位制 测试方法 载荷下热变形温度    0.45 MPa, 未退火 159 °C ASTM D648    0.45 MPa, 未退火 160 °C ISO 75-2/B    1.8 MPa, 未退火 130 °C ASTM D648    1.8 MPa, 未退火 110 °C ISO 75-2/A 线形热膨胀系数 - 流动 8.0E-5 cm/cm/°C ASTM D696, ISO 11359-2 可燃性 额定值 测试方法 UL 阻燃等级 (0.710 mm) HB UL 94

The time of developing POM in China is almost the same as that of DuPont Company, which is earlier than that of Asahi Cheng Company in Japan. However, after ten years'development, there is a big gap in technology level between China and foreign companies, which is characterized by small scale, high energy consumption, low grade and unstable product quality. In the past, POM in China missed the opportunity of industrialization of R&D achievements due to insufficient development of downstream products, small demand and planned economic system, and so on. At present, POM is only operating in pilot-scale plants, which is bound to be difficult to compete with foreign products. However, it should also be noted that POM has better conditions in terms of self-development technology level, stable operation time of 1000-ton plant and source of raw materials in domestic engineering plastics. Some experts in the industry believe that domestic technology has the ability to construct large-scale plants in some key technological links, but it needs a certain amount of capital investment. The existing production units will run well, and various auxiliary processes will be improved to prepare conditions for the expansion of the plant scale.

From the production process of POM, formaldehyde is used as the polymerization monomer in homopolymerization. Its chemical properties are very active, which brings many problems to the refining and polymerization process. The copolymerization method uses triformaldehyde as the polymeric monomer. Triformaldehyde is a stable six-segment ring. Compared with formaldehyde, it is more convenient to purify and polymerize. So when the process route of triformaldehyde appears, industry seldom considers formaldehyde as the polymeric monomer. At present, the copolymerization technology of triformaldehyde as the polymeric monomer accounts for about the total of polyformaldehyde in the world. Production capacity. Homopolyformaldehyde from the properties of resin products of two processes

Its crystallinity is slightly higher and its physical and mechanical properties are slightly stronger than that of copolymerized formaldehyde, but its thermal stability and acid-alkali corrosion resistance are obviously lower than that of copolymerized formaldehyde, and its processing temperature range is narrower, while the conditions of copolymerized formaldehyde processing and shaping are not as harsh as that of homopolyformaldehyde. During the processing, less formaldehyde gas is released from thermal decomposition, which can be recycled Obviously affect the quality of products, these advantages are valued and hoped by users.