What is plastic?

1-1. Definition of plastic

Plastics and is synonymous with synthetic resin, and it is defined as follows in JIS K 6900. "Solid with a useful shape formed artificially with polymer materials as main raw materials. However, fiber, rubber, paints, adhesives etc are excluded." In other words, it is a solid with the following three conditions, viz. plastics is a polymer material, it is given useful shape artificially, and it is solid in normal circumstances.

1-2. History of plastic

The concept of polymer compound came into existence when H. Staudingern of Germany annouced the existence of long linked polymer molecules in 1920. In the industry, plastic was synthesized even before the appearance of the concept of polymer. Bakelite invented phenolic resin in the United State, while the industrial production of urea resin adhesive started in Germany in 1918. Early industrial plastics were mainly thermosetting resins such as urea resin and phenolic resin made from chemicals made from coal. In 1920, when Staudingern introduced the concept that polymer compound is a compound with linked polymers, many studies on the synthesis of polymers were undertaken. In the 1930s, condensation linear polymers such as nylon or polyester were synthesized. Later, Ziegler and Natta et al found that a three-dimensional compound with regularity can be formed even at low pressure using catalyst, low-pressure method of polyethylene and polypropylene synthesis were industrialized. Entered an era of coal chemistry from the age of petrochemical and Japan in the 1950s, low coal plastic was mass produced. Then, with the development of automobiles and electric and electronic industry, engineering plastics as high functional resins with added functions were developed one after another and gradually industrialized.。

1-3. Salient features of plastic

(1) Light weight (low specific gravity with 1/5-1/6th weight of metal)
(2) Insulation (excellent insulation due to high electrical resistance)
(3) Corrosion resistance (no worries of rust and decay due to excellent corrosion resistance)
(4) Thermal insulation (excellent thermal insulation due to small coefficient of thermal conductivity)
(5) Nonmagnetic (does not become magnetic)