PVC profile products experienced a period of rapid development and introduction period from the time point of view, can be defined as the mid-1980s to 1990s of the twentieth century, and around 1995 to 2002. After 2003, PVC profile industry entered a transition period. The import of products: Manufacturer common pursuit of low cost, simplified window profiles section, fill a large number of formulations of calcium carbonate, resulting in low performance pvc sealing strip supply, a lot of quality problems affecting the promotion of the product. 1995 began, a number of strong businesses, start the digestion and absorption of foreign technology essence Continental profiles, developed their own doors and windows series, became the leading edge banding pvc plastic doors and windows sealed, promoting technological upgrading and development of the doors and windows, but also to the entire industry has been an unprecedented development and growth. pvc identification may be determined by determining whether the material containing chlorine pvc sealing strip, but because the vinyl chloride copolymers, polychloroprene, polyvinylidene chloride, polyvinyl chloride, and so contains a high proportion of chlorine, but also by pyridine color reaction to identify. Note that, before the test, the sample must be extracted with ether to remove the plasticizer, Test method: after the sample had taken phenyl ether was dissolved in THF, insoluble component was filtered off, methanol was added for precipitation, and after the front 75 and extracted degrees or less dry. The dried small sample need not react with 1ml of pyridine, after a few minutes pvc sealing strip processing, the scene was added 2 drops of 5% methanol solution of sodium hydroxide (1g then 20ml of sodium hydroxide was dissolved in methanol) was observed immediately what color, 5min and 1h after the observation time, respectively. Identification of different colors according to the chlorine plastic. pvc seal manufacturers, pvc seals, sea Widex Widex provided by Qingdao Rubber Material Co., Ltd. Widex Qingdao Rubber Material Co., Ltd. (www.haihuidaxiangsu.com) strong, credible, in Qingdao, Shandong industrial products industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead the sea Widex and you work into the brilliant, for a better future!