On the type of plastic and each technical term
- Thermoplastic Plastic
- Thermoset plastic
It gets softened by applying heat, and it hardens when it is cooled, once softened it gets soft again when heat is applied. By heating and cooling, it can be in fluid state or solid state.
It is inexpensive, most plastic is thermoplastic because it has high productivity, molds, materials and machinery alone, mass production is possible. Moreover, it can be recycled again by heating, so it is easy to recycle defective products.
Furthermore, due to the difference in crystal structure, it is classified as "crystalline plastic" or "non-crystalline plastic". This is whether the crystal structure is arranged in an ordered arrangement or in an amorphous form. There are various differences between the two, first the strength is higher with crystallinity.
And the transparency is higher for amorphous and the chemical resistance is higher for crystalline. Chemical resistance is the property that can withstand changes in appearance and physical properties, expansion, etc. when chemicals are used. The way of thinking is similar to the strength of plastic.
- Polyethylene, polypropylene, polytetra, liquid crystal polymer, polyphenylene sulfide, polyethylene terephthalate, polyamide, polyacetal, fluororesin and the like. In particular, polycarbonate has the highest impact resistance and heat resistance among plastics and can be used for a long time. Moreover, because it has high transparency and high processability, it is used for military supplies and a wide range of industrial products from various places.
It is safe and does not generate toxic gas because it is difficult to spread. For daily necessities, it is also used for smartphones, cameras, eyeglasses and the like.
- 2.Non-crystalline dt>
- There are vinyl chloride, vinyl acetate, polystyrene, polyvinyl alcohol, polvinyl butyral, ABS resin, methacrylic resin, polyamide (nylon resin), polystyrene, methacrylic resin and others.
When it gets hot, it gets hard, and there is a property that it does not become soft even when applying heat again.
As a characteristic of molecular bonding, it is stable, strong and resistant to heat. It is excellent in heat resistance, water resistance and chemical resistance, and it is used for home appliances, dishes, functional parts and structural parts.
For example, a breaker or an outlet. It is necessary to use thermosetting plastic because it has characteristics that melts and does not deform even when electricity and heat are transmitted. However, because the productivity is not good, the cost is high and burrs (protrusions to be produced in processing) tend to be generated, so it is necessary to process again. It also has the property that material can not be reused. p>
There are phenolic resin bakelite, melamine (decora), unsaturated polyester (UPR), epoxy, urea resin and so on.
Although the types of plastics can be roughly divided depending on their properties, heat resistance and strength are different, so there are individual plastics suitable for that product. It is necessary to identify suitable plastics and use them properly.