Understanding The Plastic Properties Of High Impact Styrene Sheet
High impact styrene sheet was developed in 1950 to improve the impact brittleness of PS. By adding rubber to polystyrene substrate, high impact styrene sheet with different properties can be produced.
In recent years, a variety of special grades of high impact styrene sheet have been developed, including flame retardant grade, stress cracking grade, high gloss grade, high impact strength grade, glass fiber reinforced grade and low residual volatility grade. They have been able to compete with expensive process resins in many application fields.
The outstanding characteristics of high impact styrene sheet are easy processing, excellent dimensional stability, high impact strength and high rigidity. High impact styrene plate is only in heat resistance. There are some limits in oxygen permeability, UV stability and oil resistance. The properties of High Impact Styrene Sheet are closely related to the content of rubber phase in the system.
Physical and chemical properties:
High impact styrene sheet is developed on the basis of PS. PS has good transparency, high hardness, easy to form and process. However, it is the most vulnerable to brittle fracture, which is constrained in use. In order to improve its service performance, butadiene rubber is added to improve its toughness during
polymerization. The impact toughness of the toughened high impact styrene plate is four times higher than that of PS.
It can be divided into low impact PS, medium impact PS and high impact line PS according to the amount added. However, the addition of rubber reduces the surface gloss. After modification, the use temperature of the material was increased. The thermal deformation temperature was 96 ℃, and the high impact styrene plate was also a kind of flammable plastic. The limiting oxygen index was 17.8. The flame was orange yellow and accompanied by a large number of black smoke. The combustion characteristics were softening, foaming, burning, and special taste of phenylene monomer.
The high impact styrene sheet can be processed by many traditional molding methods, such as injection molding, structural foam molding, sheet and film extrusion, hot forming and blow molding. Hips resin absorbs water slowly, so it does not need to be dried in general. Sometimes too much moisture on the surface of the material will be absorbed, which will affect the appearance quality of the final product. Drying at 75 ℃ for 2-3 hours can remove the excess water.
Extrusion of film, sheet and profile is the most widely used processing and forming method for high impact styrene sheet. Impact polystyrene has a wide processing range, so it becomes one of the most
easily thermoformed resins. Generally, the resin melting temperature of common extrusion equipment is 205 - 255 ℃
High impact styrene sheet has excellent thermal stability and shear stability. It can receive a lot of recycled materials without reducing the product performance. The recycled materials used in the thermoforming process can be as high as 60%.
Injection molding is the most widely used processing and molding method next to extrusion. The processing temperature is 200-260 ℃, but for the flame-retardant high impact styrene sheet, the processing temperature must be lower than 240 ℃, so as to prevent the degradation reaction of additives. The melt index of resin processed by injection molding is generally 5.0-15.0 g / min.
The most special use of high impact styrene sheet is as packaging and disposable materials, especially food packaging materials and tableware. The main applications include daily packing containers. Cups, covers and plates for vending machines and sub containers. Bowl and so on. Disposable products such as plates and saucers, bottle caps, safety razors, pen holders, etc. are also part of the high impact styrene sheet consumption.
In recent years, special products have become the focus of high impact styrene sheet product development. The newly developed high impact styrene sheet can compete with the engineering resin in some application fields, some of which are much higher than the current products in quality. Instruments and consumer appliances are one of the growing markets of high impact styrene sheet, including small instruments, refrigerator inner wall and internal parts, TV shell, air conditioning components, commercial machines and audio and video cassettes.
Special grade high impact styrene sheet resin has replaced the engineering plastics with high price in many fields. A kind of high impact strength and high temperature resistant styrene board has even been used as automobile interior parts.