How To Change The Hardness Of Plastics?
1. The concept and representation of hardness
Hardness refers to the ability of a material to resist the pressing of other hard objects into its surface. The magnitude of the hardness value is a conditional quantitative representation of the degree of softness and hardness of the material. It is not a purely defined physical quantity.
The hardness value depends not only on the material itself, but also on the test conditions and the measurement method, that is, the different hardness measurement methods, and the hardness values measured for the same material are not the same. Therefore, to compare the hardness between materials, the hardness values measured by the same measurement method must be comparable.
The methods commonly used to indicate hardness are as follows:
(1) Shore hardness;
(2) Rockwell hardness;
(3) Mohs hardness;
2. Blending to improve the hardness of plastics
An improved method of plastic blending is to blend a high hardness resin in a low hardness resin to increase its overall hardness. Common blending resins are: PS, PMMA, ABS and MF, etc. The resins to be modified are mainly PE, PA, PTFE and PP.
3. Composite improved plastic hardness
The method of improving the hardness of the plastic composite is to combine a high hardness resin on the surface of the low hardness plastic product. This method is mainly suitable for extrusion products such as plates, sheets, films and pipes. Commonly used composite resins are PS, PMMA, ABS and MF.
4. Plastic surface hardness improvement
The method refers to only improving the hardness of the appearance of the plastic product, and the hardness inside the product is unchanged. This is a low cost hardness improvement method.
This modification method is mainly used for housings, decorative materials, optical materials, and daily necessities. This modification method mainly includes three methods of coating, plating and surface treatment.