Several Common Plastic Raw Materials

Plastic is a common item in our lives. It is an organic synthetic polymer material that is used in a wide range of applications. To date, there are nearly a hundred different types of plastic materials known. By function plastics are divided into three types: general purpose plastics, engineering plastics and super engineering plastics.

There are seven types of plastics in common use. A triangular recycling symbol consisting of three arrows and the numbers 1-7 therein can usually be found at the bottom of the plastic. These numbers represent the type of resin used in the plastic.

The next section describes some of the plastic materials used in the daily production of products in our factories.

PP

The density of PP is around 0.9g/cubic, the melting point of injection moulding is around 180 degrees. Our factory is using two kinds of PP, there are high transparent and semi-transparent. Generally high permeability is used for more transparent products, without adding colour or adding a little colour, while semi-permeable is used for solid colour products.

PE

The density of PE is around 0.95g/cubic, the melting point of injection moulding is around 180 degrees.  There are two types in use in factories: high pressure and low pressure. High-pressure is softer, low-pressure is harder (but not as hard as PP), tougher and less prone to breakage.

PET

PET is a milky white or light yellow highly crystalline polymer with a smooth and glossy surface. It is creep resistant, fatigue resistant, abrasion resistant and dimensionally stable, with low abrasion and high hardness, and has the greatest toughness of any thermoplastic.

AS/PS

The density of AS/PS is around 1.07 g/cubic and the melting point of the injection moulding is around 220 degrees. The characteristic is that it is transparent and the disadvantage is that it is fragile. Usually used for cold water cups or lunch box lids with high transparency.

TPR

There is no standard for TPR density. As it is a modified material and food grade testing is generally not available. The melting point for injection moulding is around 160 degrees and is generally used for sealing products.

TRITAN

The advantages of TRITAN are that it is BPA free, clear and transparent, impact resistant, high temperature resistant, good resistance to chemical and hydrolysis.