Some of the secretions of trees often form resin, but amber is a fossil of resin. Although shellac is also regarded as resin, it is a deposit of lac insects secreted on the tree. Shellac paint made from shellac was initially used only as wood as a preservative, but with the invention of the electric motor, it became the earliest insulating paint. However, after entering the 20th century, natural products have been unable to meet the needs of electrification, prompting people to find new cheap substitutes.
As early as 1872, the German chemist Bayer (A. Bayer) first discovered that phenol and formaldehyde can quickly form a reddish brown lumpy or sticky substance when heated under acidic conditions, but the experiment was stopped because they could not be purified by classic methods. After the 20th century, phenol was already available in large quantities from coal tar, and formaldehyde was also produced in large quantities as a preservative. Therefore, the reaction products of the two have attracted more attention, and hope to develop useful products, although many people have spent a lot of labor on it , But none of them achieved the expected results.
In 1904, Beckland and his assistants also carried out this research. The original purpose was just to make insulating lacquer instead of natural resin. After three years of hard work, finally in the summer of 1907, not only the insulating lacquer was made, And also made a real synthetic plastic material-Bakelite, which is known as "bakelite" "bakelite" or phenolic resin.
Once Bakelite came out, the manufacturer soon discovered that it can not only manufacture a variety of electrical insulation products, but also make daily necessities. Edison (T. Edison) is used to make records, and soon announced in the advertisement: Bakelite has made thousands of Products, and for a time hailed Beckland’s invention as the “alchemy” of the 20th century.
Phenolic resins with coal tar as the original particle have been the first in the production of various synthetic resins until 1940, reaching more than 200,000 tons per year. However, with the development of petrochemical industry, polymerized synthetic resins such as polyethylene and The production of polystyrene is also expanding. With the establishment of many large-scale plants with an annual output of more than 100,000 tons of these products, they have become the four types of synthetic resins with the largest output today. Synthetic resins and additives are added to obtain plastic products through various molding methods. Today there are dozens of plastic varieties. The world's annual output is about 120 million tons, and our country is also more than 5 million tons. They have become production and living. And basic materials for national defense construction.
Synthetic resin is the most important component of plastic, and its content in plastic is generally 40% to 100%. Because of the large content, and the nature of the resin often determines the nature of the plastic, people often think of resin as a synonym for plastic. For example, mix polyvinyl chloride resin with polyvinyl chloride plastic, phenolic resin and phenolic plastic. In fact, resin and plastic are two different concepts. Resin is an unprocessed raw polymer, which is not only used to make plastics, but also as a raw material for coatings, adhesives and synthetic fibers. In addition to a very small part of plastic containing 100% resin, most plastics, in addition to the main component resin, also need to add other substances.