At present, thermoplastic products are closely related to our lives. Let's take everyone to learn about PP (polypropylene).
PP is a general-purpose resin closely related to our daily life. It is the most important downstream product of propylene. 50% of the world's propylene and 65% of China's propylene are used to make polypropylene. Polypropylene is the fastest growing general-purpose thermoplastic resin in the world, second only to polyethylene and polyvinyl chloride in total usage.
PP is a crystalline plastic, generally white particles with a waxy luster on the surface and irregular round shapes. Density is the lightest of all plastics. It has a relatively obvious melting point. According to the difference of crystallinity and molecular weight, the melting point is about 170°C, and its decomposition temperature is above 290°C, so it has a wide range of molding temperature and molding shrinkage.
The service temperature of PP can reach 100°C, it has good electrical properties and high-frequency insulation, and is not affected by humidity. But it is brittle at low temperature, not wear-resistant, and easy to age. It is suitable for making general mechanical parts, corrosion-resistant parts and insulating parts. In addition, hinge products made of thermoplastic PP materials have outstanding fatigue resistance.
The hygroscopicity of PP is very small, and it is not necessary to dry it before molding. If it is not stored properly, it can be dried at about 70 ° C for 3 hours. The molding fluidity is good, but the shrinkage range and shrinkage value are large, and shrinkage cavities, dents, and deformation are prone to occur. The cooling speed is fast, and the pouring system and cooling system should dissipate heat slowly.
Thermoplastic PP (polypropylene) should pay special attention to controlling the melting time of raw materials during molding. PP is easy to decompose when in contact with hot metal for a long time. Melt fracture is easy to occur, and the directionality is obvious at low material temperature, especially at low temperature and high pressure.
In terms of mold temperature, when the temperature is lower than 50°C, the plastic parts are not smooth, and poor welding and flow marks are prone to occur, and warping deformation is prone to occur when the temperature is above 90°C. The thickness of the plastic wall must be uniform to avoid lack of glue and sharp corners to prevent stress concentration.
ATP Polymer is a leading polymer compound manufacturing company, supplying specialty plastics to customers around the world. ATP Polymer Technology co, LTD (ATP) is a national high-tech enterprise dedicated to R&D, production and sales of modified thermoplastic polymers, low-smoke and halogen-free and other new environmentally friendly polymer materials.
The main products include TPU, TPEs, LSZH, XLPE, etc. ATP, your reliable polymer material partner.
