Plastic Material: PP Resin
- PP-H has the highest crystallinity and therefore the highest hardness, tensile strength and stiffness. PP-R has a very good long-term creep strength at higher temperatures.
Advantage: Good long-term creep strength at higher temperatures, better strength than the other two kinds.
Disadvantage: Poorer impact resistance (more brittle), less stiffness, poor dimensional stability, and age-sensitive.
Application:extrusion molding, blow molding, injection molding. Products such as plastic bottle, packaging strap, brush, cord/rope/lanyard, plastic woven bag, toy, microwave meal box, document folder, electronic equipment, packaging film, etc.
How to classify: When it is burned with fire, the stretched filament is flat, because the extension is not very good, so the stretch is not long.
- PP-R (PP Random Co-polymeride): Also known as "Polypropylene Random", which has the best characteristic among these three kinds of PP. Produced by adding in 1~4% of vinyl, heaten, pressurized, and use of catalyst. Vinyl monomer distributes randomly among the molecular chain, so it decreases the crystallinity and lower the melting point of polymer, enhance the impact resistance, aging resistance, and heat resistance. From this we can see, adding suitable amount of vinyl is able to affect the heat resistance, mechanical properties, and machining performance. In particular, the more irregular the distribution in molecular chain, the better the improvement of polypropylene properties.
Advantage: Good comprehensive performance. The appropriate amount of vinyl monomer increases hardness, stiffness, nice heat resistance, dimensional stability, outstanding stiffness at low temperature, transparancy, glossiness, and fine appearance.
Application: extrusion moulding, blow molding, film-grade, injection molding. Products such as tubing, infusion bottle, transparent container / housewares, one time syringe, film packaging, etc.
How to classify: It will not turn black after burning, and because the material has better toughness, it can draw a long round wire.
- PP-B (PP Block Co-polymeride): The vinyl content is higher than PP-R, it has 7～15% vinyl monomer generally, however, because the probability that two vinyl monomers and three monomers are connected together in PP-B is very high, the vinyl monomer only exists in the block, and the regularity of PP-H is not reduced, so it cannot improve the melting point, long-term heat resistance, and oxidation resistance by adding vinyl.
Advantage: At room temperature and low temperature, it has great impact resistance, suitable hardness; compare with PP-R, it has less transparency and glossiness.
Application: extrusion molding, injection molding. Products such as baby stroller, sport equipment, luggage/suitcase, paint barrel, battery box, etc.
How to classify: After burning, it will not turn black and can pull out a long round wire.
- Common feature of above three kinds: non-hygroscopic (only adherent moisture on the surface, not absorbed), resistant to chemical, acidity, and alkalinity, poor resistance to oxidation under high temperature.
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