General purpose plastics: general purpose plastics refer to plastics with low mechanical properties and heat resistance, which can not be used as structural materials, but with large amount and wide range. Five general plastics: polyethylene, polypropylene, polystyrene, polyvinyl chloride, ABS (propylene, polycarbonate, polyformaldehyde, polyimide and polyamide resin commonly used as foam plastics, etc.) are well known. Among the synthetic fibers, polyester fiber (ester fiber), acrylic fiber (polyacrylonitrile fiber), nylon (polyamide fiber) have already entered thousands of households.
In synthetic rubber, styrene butadiene rubber and polybutadiene general purpose grade polyphenylene ethylene (GPPS)
, and may transition to a loose balance, the price will fall. But if this year's production of high-pressure rubber hose is not ideal, then the tension and balance will transition to a state of short supply, and the price may rise again. Therefore, this year's high-pressure rubber tube price trend is very large. There are many suppliers, purchasers and manufacturers. The steel wire woven high-pressure rubber tube structure is composed of liquid resistant synthetic rubber inner layer, steel wire reinforcement layer and weather resistant synthetic rubber outer layer. Application: mainly used for aircraft fuel oil, mine hydraulic support, oil field exploitation, engineering machinery for China market.
Characteristics and application of polystyrene
I. characteristics
1. GPPS characteristics
GPPS is colorless, odorless, tasteless, glossy and transparent particles. Light weight, low price, low water absorption, good coloring, dimensional stability, good electrical performance, transparent products, easy processing.
GPPS is soluble in aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic ketones and esters, but only in acetone. It can resist the action of some mineral oil, organic acid, alkali, salt, lower alcohol and its aqueous solution. The mechanical properties and dimensional stability can be maintained in humid environment due to the low water absorption. It has excellent electrical performance, high volume resistance and surface resistance, and is not affected by temperature and humidity changes, nor by corona discharge. Radiation resistance is also very good.
GPPS is brittle and easy to crack, low impact strength, poor heat resistance, can not withstand boiling water, can only be used at low temperature and low load. Poor sunlight resistance, flammable. Black when burning, and have special stink.
2 Use of PS
General purpose polystyrene, can be used in daily necessities, electrical, instrument shell, toys, lamps, household appliances, stationery, cosmetics containers, rooms
Interior and exterior decoration, fruit plate, optical parts (such as prism, lens), lens, window mirror and molding, lamp, telecommunication accessories, electric frequency capacitor film, high frequency insulation materials, TV containers, waveguide, chemical containers, etc. Suspension polymerized resin can be made into foam plastics of different density, which can be used as heat insulation, sound insulation, shockproof, floating, packaging materials, cork substitutes, preformed foam can be used as water filtering medium and light concrete, low foaming plastics can be made into synthetic wood for furniture, etc.
3.High impact polystyrene (HIPS) can be injection molded or extruded into various products, suitable for the shell of household electrical appliances, electrical appliances, instrument accessories, refrigerator lining, plate, television, recorder, telephone shell, stationery and educational supplies, toys, packaging containers, daily necessities, furniture, tableware, tray, tableware, structural foam products, etc.
The processing of polystyrene
Polystyrene has good fluidity, processability, easy coloring and good dimensional stability. It can be processed into various parts by injection molding, extrusion, blow molding, foaming, thermoforming, bonding, coating, welding, machining, printing, etc. It is specially suitable for injection molding. The materials can be directly applied without drying during injection molding. However, in order to improve the quality of the product, it can be pre dried for 1-2 h in a blast oven at 55 ℃ ~ 70 ℃. The detailed processing conditions are as follows: the barrel temperature is about 200 ℃, the mold temperature is 60-80 ℃, the injection temperature is 170-220 ℃, and the injection pressure ratio is 1.6-4.0. After forming, the products shall be treated at 70 ℃ for 2-4h in infrared lamp or blast oven.