Ordinary PP is often used in mold injection coat hangers, chairs, stools, barrels, basins, toys, stationery, office supplies, furniture, hinges, turnover boxes and so on.Modified PP is used for washing machine barrel, TV shell, fan blade, refrigerator lining, small home appliance shell, etc.
Polypropylene is a thermoplastic resin made by polymerization of propylene.According to the position of methyl arrangement, it can be divided into three kinds: ① isotactic polypropylene, ② atactic polypropylene and ③ interisotactic polypropylene.
Characteristics of PP
PP non-toxic, tasteless, can be soaked in 100℃ boiling water without deformation, no damage, common acid, alkali organic solvents almost no effect on it is mostly used for tableware.Soybean milk bottles, yogurt bottles, juice bottles, microwave lunch boxes melting point up to 167℃, is the only plastic box can be put into the microwave oven, can be reused after careful cleaning.
Small density, strength stiffness, hardness and heat resistance are better than low pressure polyethylene, can be used at about 100 degrees.
Has good electrical properties and high frequency insulation is not affected by humidity, but low temperature brittle, not wear-resistant, easy to aging.
Preparation technology of PP
PP is generally used for injection molding: PP injection products can account for about half, daily necessities with ordinary PP as raw material, auto parts to enhance or toughen PP as raw material, other uses with high impact strength and low embrittlement temperature of PP-C raw material.
Points for Attention in Use
Some microwave box, box body to 5 PP manufacturing, but the box lid is made to 1 PE, because PE can not withstand high temperature, it can not be put into the microwave oven with the box body.
Polyvinyl chloride (PVC)
PVC is a polymer of free radical polymerization of polyethylene monomer. It is one of the earliest industrialized resin varieties. It is the largest variety of resin before the 1960s, and it is only the second in the late 1960s.
According to the molecular weight, PVC can be divided into general type (the average degree of polymerization is 500-1500) and high degree of polymerization (the average degree of polymerization is greater than 1700) two types.Commonly used PVC resin is mostly general type.
The main properties of PVC:
1) general performance: PVC resin is a white or light yellow powder, the hardness of its products can be adjusted by adding the number of plasticizers, made of soft and hard products.Pure PVC water absorption and permeability are very small.
2) Mechanical properties: PVC has high hardness and mechanical properties, and increases with the increase of molecular weight, but decreases with the increase of temperature.The number of plasticizers added into PVC has a great influence on the mechanical properties. Generally, the mechanical properties decrease with the increase of plasticizer content.The wear resistance of PVC is general.
1) the application of hard PVC products
Pipe material: used for upper water pipe, lower water pipe, gas pipe, infusion pipe and thread pipe profiles: used for doors, Windows, decorative boards, wood lines, furniture and stair handrails.
Plate: can be divided into corrugated board, dense board and foamed board, used for siding, ceiling, shutter, floor and so on.Sheet: used for plastic products, such as a variety of packaging boxes.Silk: used for window screen, mosquito net, rope and so on.
Bottle category: food, medicine and cosmetics packaging materials.
Injection products: pipe fittings, valves, office supplies housing and electrical housing, etc.
2) application of soft PVC products
Film: agricultural greenhouse film, packaging film, raincoat film, etc.
Cable: used for medium and low voltage insulation box sheathed cable material.Footwear: soles and finishes.
Leather: artificial leather, floor leather and wallpaper, etc.Others: soft transparent tubes, records and gaskets, etc.