The secretions of some trees often form resins. As early as 1872, German chemist A. Bayer first discovered that phenol and formaldehyde can quickly form reddish-brown lumps or sticky substances when heated under acidic conditions, but they cannot be purified by classical methods. and stop the experiment. After the 20th century, phenol can be obtained in large quantities from coal tar, and formaldehyde is also produced in large quantities as a preservative, so the reaction products of the two are more attractive, and it is hoped to develop useful products, although many people have spent a lot of labor for it. , but did not achieve the expected results.
In 1904, Beckland and his assistants also carried out this research. The initial purpose was to make insulating paints that replace natural resins. After three years of hard work, in the summer of 1907, not only insulating paints were produced, And also produced a real synthetic plastic material – Bakelite, which is known as “bakelite”, “bakelite” or phenolic resin. Once Bakelite came out, manufacturers soon found that it could not only make a variety of electrical insulation products, but also make daily necessities. I love T. Edison for making records, and soon announced in advertisements that thousands of products have been made with Bakelite. , So Baekeland’s invention was hailed as the “alchemy” of the 20th century.
Before 1940, the phenolic resin with coal tar as the original particle always ranked first in the output of various synthetic resins, reaching more than 200,000 tons per year, but since then, with the development of petrochemical industry, polymerized synthetic resins such as polyethylene The output of , polypropylene, polyvinyl chloride and polystyrene has also continued to expand. With the establishment of many large factories 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.
Today, synthetic resins and additives can be used to obtain plastic products through various molding methods. There are dozens of varieties of plastics, and the world’s annual output is about 120 million tons. They have become the basic materials for production, life and national defense construction.
Post time: Nov-12-2022