• Plastics are manufactured synthetically using raw materials mostly from natural gas and petroleum, or from coal mines, forests, farms, paper and textile mills.
• In addition to the raw materials chosen, the plastics are generally compounded with some other substances so as to impart certain specific properties to the product.

• Usually such moulding compositions are prepared from two or more of the following materials groups which are named according to their function

   

LUBRICANTS:-

1. Lubricants helps during moulding operations, especially low or during room temperature moulding.
2. The use of lubricants imparts flawlessness, and glossy finish to the plastics products.
3. This is because the lubricants tends to get dispersed towards outer surface of the finished product, hence during, moulding they form a layer between the article and mould.
4. This layer prevents the plastic material from sticking to the surface of the mould, and thereby facilitating the moulding operations.

5. Commonly used lubricants are soaps, or esters of fatty acids such as oleic and stearic or waxes.

    

STABILIZERS:-

1. Stabilizers help to improve thermal stability of the plastic.
2. These are required especially in the processing stage for plastics, which have tendency to decompose or change their colours at moulding temperatures.