Our products such as shaker bottle, salad bowl, sports bottle, the main body of the product generally use PP materials, why use PP materials, PP properties and advantages?
PP raw material, chemical name: polypropylene.
Features: low density, rigid strength.
1 Physical properties:
Polypropylene is a non-toxic, odorless, odorless, milky white, highly crystalline polymer with a density of only 0.90--"0. 91g/rm. It is one of the lightest varieties of all plastics. It is particularly stable to water. The water absorption rate in water is only 0. O1%, the molecular weight is about 80,100,000. The moldability is good, but the shrinkage rate is large (1% to 2.5%). The thick-walled products are easy to be sunken, and some dimensional precision is high. Parts are also difficult to meet the requirements, the surface of the product is glossy and easy to color.
2 Mechanical properties:
Polypropylene has high crystallinity and regular structure, and thus has excellent mechanical properties. The absolute value of the mechanical properties of polypropylene is higher than that of polyethylene, but it is still a low grade in plastic materials, and its tensile strength can only reach 30 MPa or slightly higher. Polypropylene with a higher isotactic index has higher tensile strength, but as the isotactic index increases, the impact strength of the material decreases, but does not change after falling to a certain value. Temperature and loading rate have a great influence on the toughness of polypropylene. When the temperature is higher than the glass transition temperature, the impact fracture is ductile fracture, brittle fracture below the glass transition temperature, and the impact strength value is greatly reduced. Increasing the loading rate increases the temperature at which the ductile fracture transitions to brittle fracture. Polypropylene has excellent bending fatigue resistance, and its product can be bent 106 times at normal temperature without damage. However, at room temperature and low temperature, the impact strength is poor due to the high degree of molecular structure regularity. The most outstanding performance of polypropylene is the resistance to bending fatigue, commonly known as the 100% plastic.
3 thermal performance:
Polypropylene has good heat resistance, and the product can be sterilized at a temperature above 100 ° C, and it is not deformed at 150 ° C under the condition of no external force. The embrittlement temperature is -35 ° C, embrittlement occurs below -35 ° C, and the cold resistance is not as good as polyethylene. The reported values for the glass transition temperature of polypropylene are 18qC, OqC, 5°C, etc., which is also because people use different samples, in which the ratio of crystal phase to amorphous phase is different, so that the chain length of the amorphous part in the molecular chain is different. Caused by. The melting temperature of polypropylene is about 40-50% higher than that of polyethylene, about 164-170 ° C, 100% isotactic polypropylene melting point is 176 ° C
4 Chemical stability:
Polypropylene has good chemical stability. Besides being attacked by concentrated sulfuric acid and concentrated nitric acid, it is stable to various other chemical reagents. However, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons can soften polypropylene and Swelling, while its chemical stability increases with the increase of crystallinity, so polypropylene is suitable for making various chemical pipes and fittings with good anti-corrosion effect.
5 Electrical properties:
It has a high dielectric constant and can be used to make heated electrical insulation products as temperature rises. It also has a high breakdown voltage and is suitable for use as an electrical accessory. It has good resistance to voltage and arc resistance, but it has high static electricity and is easy to age with copper.
Phone: +0086-189 2378 7906
Tel: +0086-189 2378 7906
Add: wangchun industrial park, Ningbo