PP Polypropylene GranulesThe isotactic polypropylene in the resin is a highly crystalline (crystallinity close to 95%) thermoplastic resin having a regular configuration. In the commonly used plastic, it is a lighter variety. People often say that PP polypropylene resin refers to isotactic polypropylene. What are the performance characteristics of polypropylene PP particles?

PP Polypropylene Granules

1. It is a milky white waxy substance, tasteless and odorless, with a density of 0.9-0.91g/cm3.

2. Mechanical strength, rigidity and stress cracking resistance are better than high-density polyethylene; good wear resistance, high hardness, good high temperature and impact resistance (but a sharp drop below -5 ℃), and good resistance to repeated folding.

3. Good heat resistance, thermal deformation temperature 114 ℃, Vicat softening point greater than 140 ℃, melting point 164-167 ℃, working temperature up to 150 ℃ under no-load conditions, and disinfection at 130°C, continuous to high working temperature of 110-120°C.

4, good chemical stability, in addition to strong oxidizing acid (such as fuming sulfuric acid, nitric acid) has a corrosive effect on it, and most chemicals do not react chemically; insoluble in water, almost no water absorption, in water 24 hours Water absorption is only 0.01%. However, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons soften or swell it.

5. Excellent electrical insulation performance, good voltage resistance and arc resistance.

6. Polypropylene PP particles are easy to age under the action of light, heat and oxygen during use; they will age and become brittle in the atmosphere for 12 days, and will deteriorate in the room for 4 months. The materials used in the product are added with ultraviolet absorbers and antioxidants to improve the weather resistance of the product.

The transparency of the product is better than that of high density polyethylene products.

8. Poor cold resistance, low low temperature impact strength, poor toughness, large static electricity, poor dyeing, printing and adhesion. In the application, additives can be added to the raw materials or by blending, copolymerization and other methods to improve this performance.

PP Polypropylene GranulesIt has good fluidity and formability at the melting temperature. There are two characteristics in the processing process: one is that the viscosity of PP melt decreases significantly with the increase of shear rate (less affected by temperature); the other is that the molecular orientation is high and the shrinkage rate is large.

The processing temperature of polypropylene PP particles is about 200-300 ℃, and the thermal stability is good (the decomposition temperature is 310 ℃). However, at high temperatures (270-300°C), the residence time in the tube is long and degradation may occur. Since the viscosity of polypropylene plastic particles decreases significantly with the increase of shear rate, increasing the injection pressure and injection speed will improve its fluidity, shrinkage deformation and sag. The temperature should be controlled at 30-50. The polypropylene melt can be shaped into the front end through a very narrow die gap. During the melting process, a large amount of heat of fusion (higher specific heat) must be absorbed, and the product is hot after demolding. There is no need to dry polypropylene particles during processing, and the shrinkage and crystallinity of polypropylene are lower than polyethylene.