The yellow translucent sticky substance secreted by some tree trunks is resin. The purple sticky substance secreted by a lac insect produced in India is also a resin, which is an animal-derived resin. They are all natural resins.
Dissolve resin in solvent to form paint or coating. Turpentine and shellac have been used as coatings since ancient times. Put the resin in a roller and roll it into thin sheets. If it is transparent, it is cellophane. Resin solution or melt is extruded through fine holes, dried and cooled to form fibers. After the resin is put into the mold, it is heated and pressed into plastic products. Natural resin is transferred underground for several years and becomes amber under certain conditions. This is a natural plastic product, which has long been made into ornaments and cigarette holders by officials and businessmen in ancient China. At present, amber in various markets in the world is mainly produced in the Baltic region of Europe. But in recent years, jewelers have gradually turned their attention to Mexico. The ancient Maya in Mexico called amber "the stone of the sun". It's just that Mexican amber is hidden in a tunnel on the edge of a cliff, and the digger must bend down in the dark tunnel and work hard with weak light. Among them are children who are only six or seven years old.
Chemically speaking, resin is a polymer compound. Nitrocellulose is a polymer compound. In 1844, nitrocellulose solution was extruded into filaments. 1847, Maillard, a medical college student, dissolved nitrocellulose in a mixed solution of ethanol and ether, which was called "Koro tincture" and was used to smear wounds. After the solvent evaporates, a film is left to protect the wound. 185 1 year, British photographer Archer used it to make movies. Others use it to make small clothes and hair accessories. This began the initial stage of plastic manufacturing.
Pass, a metal art dealer in Birmingham, England, has done a lot of experiments in 1855~ 1862. After adding camphor and a small amount of castor oil to Coro tincture, the solvent evaporates to form a hard substance, which becomes soft when heated. After adding various pigments, it is molded into various objects. It was originally called Xilongrit Gerrit, which came from the Greek word "wood" and was later called "Parker" by his surname. 1866 Paxsing Company was established for production. Due to inaccurate ingredients and other reasons, the company went bankrupt two years later. Speer, another British businessman who runs tarpaulins, took over the company and changed its name to Si Long Ritter Company to continue production, and its output reached its peak in the 1920s.
Meanwhile, J. Hai Ete, a printer in New Jersey, USA, is experimenting with fake ivory. At that time, due to the lack of ivory and raw materials for making billiards in the United States, two billiards dealers offered a reward of $65,438+$0,000 to collect alternative raw materials for making billiards. After learning about it, Heott cooperated with his brother Heott to develop it. At first, they glued sawdust and shredded paper, but the quality was poor. Once I accidentally cut my finger, and the wound was painted with Corot tincture. I found that Corot tincture was very viscous, and I learned that the British used it to make paroxetine, so I tried it. They only added camphor, not castor oil, to the ethanol and ether solution of nitrocellulose, and tried to prevent the product from wrinkling due to solvent volatilization during molding. Finally, they made an artificial billiards, which was patented under the commodity name "celluloid" on April 6, 187 1, and celluloid company was established in 1872. They not only use celluloid to make billiards, but also use it to make photographic films, combs, waterproof cuffs, wrist guards and chest protectors. And even sold to all parts of Asia, China and Japan. 1898, British Gibb invented celluloid table tennis.
Celluloid has achieved commercial success, surpassing paxson and Si Long Ritter. The Heott brothers didn't get the bonus and became wealthy businessmen. However, the application of nitrocellulose in industrial production is limited because of its flammability.
Phenolic resin makes up for this shortcoming. Phenolic resin is the product of the reaction between phenol and formaldehyde, which was created by Belgian-born American chemist Backlander.
Backlander received his doctorate in natural science from Ghent University, where he was an assistant professor of chemistry, and then moved to the United States. He once invented a kind of light-sensitive printing paper, obtained a monopoly fund, became rich economically, and set up a laboratory in his home to engage in manufacturing research.
He initially tried to make a substitute for Indian shellac. Lac is widely used in coating, papermaking, printing and medicine. The United States needs to import a lot from India every year. He read a paper on the reaction between phenol and formaldehyde published by German chemist Bayer in 1872. This reaction produced a black sticky object which was difficult to remove from the container. Because it is insoluble in water and other solvents, it must be discarded with the container.
After two years of experimental research, Backlander designed and built a solid reaction vessel, which was successful under the conditions of increasing pressure and temperature and selecting catalyst.
Backlander added sawdust to phenolic resin and heated it under pressure to make various products. 1909, he founded a company named after his own surname, and named the product Beckritt after his own surname. We call it bakelite, which is very suitable. Because of its good electrical insulation, high mechanical strength, heat resistance and water resistance, it is widely used in the production of electrical industry to manufacture electrical sockets and lamp holders. Especially after the First World War, the rapid development of radio, radio and other electrical appliances industries has increased the demand for it. It has been used ever since.
However, it is a thermosetting plastic, not a thermoplastic. This can't be said to be its shortcomings, just its performance. Thermosetting plastics will soften at the initial heating and can be molded into a certain shape, but will harden and solidify after heating for a certain time or adding additives, and will not soften after reheating and will not be dissolved in solvents. Its molecules are mostly reticulate. Thermoplastics soften when heated, can be shaped into a certain shape, harden after cooling, soften after reheating and harden after cooling. Most of their molecules are linear.
At the same time, 1897, Clichy, a printer in Hanover, Germany, and Spieler, a chemist in Bavaria, used casein to react with formaldehyde to produce a resin, which was made into a plastic with similar bone hardness. It was sold in the market under the trademarks of Galaritz and Elilud, and was used to make white blackboards in school classrooms. Latvian chemist Sutez also obtained the patent of this product at 1909, and 19 13 was produced in Britain. Casein can be extracted from milk, soybeans and peanuts, so these substances have also become raw materials for making plastics. This kind of plastic is still used to make buttons and some handicrafts.
19 18, Czechoslovakian chemist H. John obtained a patent for the preparation of resin by the reaction of urea and formaldehyde. This urea (urea) formaldehyde resin is colorless, light-resistant, high in hardness and strength, non-flammable and light-permeable. After several years of research, Austrian chemist Pollack thinks this is a good glass substitute. He made glass windows and assembled the doors and windows of a university. But soon the glass broke. It turns out that urea-formaldehyde resin is easy to absorb moisture in the air when it is wet, but it is easy to release moisture after drying. In this way, the glass is broken by internal tension. In order to overcome this shortcoming, celluloid filler was used at that time, but it lost its transparency. Nevertheless, this resin is still used to make clothing products. Nowadays, this resin is widely used for gluing and impregnating wood, as well as treating fabrics and paper.
In the 1920s, furfural C4H3OCHO was used to replace formaldehyde to make resin. Furfural, also known as furfural, comes from agricultural and sideline products such as rice bran, cotton husk and corncob, which reduces the price of products. Melamine formaldehyde resin reappeared in 1930s. Melamine C3H6N6 is made of calcium carbide. The plastic made of melamine formaldehyde resin has the characteristics of fire resistance, water resistance and oil resistance, and can be used to make arc-resistant materials.