|
|Section4= }} Bakelite ( , sometimes spelled Baekelite), or polyoxybenzylmethylenglycolanhydride, is an early plastic. It is a thermosetting phenol formaldehyde resin, formed from a condensation reaction of phenol with formaldehyde. It was developed by Belgian-born chemist Leo Baekeland in New York in 1907. One of the first plastics made from synthetic components, Bakelite was used for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings, and such diverse products as kitchenware, jewelry, pipe stems, children's toys, and firearms. The "retro" appeal of old Bakelite products has made them collectible. Bakelite was designated a National Historic Chemical Landmark on November 9, 1993 by the American Chemical Society in recognition of its significance as the world's first synthetic plastic.〔(【引用サイトリンク】title=Bakelite: The World’s First Synthetic Plastic )〕 ==History== Baekeland was already wealthy, due to his invention of Velox photographic paper, when he began to investigate the reactions of phenol and formaldehyde in his home laboratory. Chemists had begun to recognize that many natural resins and fibres were polymers. Baekeland's initial intent was to find a replacement for shellac, a material that was in limited supply because it was made naturally from the excretion of lac bugs. Baekeland produced a soluble phenol-formaldehyde shellac called "Novolak", but it was not a market success.〔 Baekeland then began trying to strengthen wood by impregnating it with a synthetic resin, rather than coating it.〔 By controlling the pressure and temperature applied to phenol and formaldehyde, Baekeland produced a hard moldable material which he named "Bakelite".〔(【引用サイトリンク】 work = Plastics )〕 The first synthetic thermosetting plastic ever made, Baekeland speculated on "the thousand and one... articles" that it could be used to make.〔 Baekeland considered the possibilities of using a wide variety of filling materials, including cotton, powdered bronze, and slate dust, but was most successful with wood and asbestos fibers.〔 Baekeland filed a substantial number of patents in the area.〔 His "Method of making insoluble products of phenol and formaldehyde" was filed on July 13, 1907 and granted on December 7, 1909. Baekeland also filed for patent protection in other countries, including Belgium, Canada, Denmark, Hungary, Japan, Mexico, Russia, and Spain. He announced his invention at a meeting of the American Chemical Society on February 5, 1909. Baekeland started semi-commercial production of his new material in his home laboratory, marketing it as a material for electrical insulators. By 1910, he was producing enough material to justify expansion. He formed the General Bakelite Company as a U.S. company to manufacture and market his new industrial material. He also made overseas connections to produce materials in other countries.〔 Bijker gives a detailed discussion of the development of Bakelite and the Bakelite Company's production of various applications of materials.〔 As of 1911, the company's main focus was laminating varnish, whose sales volume vastly outperformed both molding material and cast resin. By 1912, molding material was gaining ground, but its sales volume for the company did not exceed that of laminating varnish until the 1930s. As the sales figures also show, the Bakelite Company produced "Transparent" cast resin (which did not include filler) for a small ongoing market during the 1910s and 1920s.〔 Blocks or rods of cast resin, also known as "artificial amber", were machined and carved to create items such as pipe stems, cigarette holders and jewelry.〔 However, the demand for molded plastics led the Bakelite Company to concentrate on molding, rather than developing market opportunities for cast resins. The Bakelite Corporation was formed in 1922 (after patent litigation favorable to Baekeland) from a merger of three companies: Baekeland's General Bakelite Company; the Condensite Company, founded by J.W. Aylesworth; and the Redmanol Chemical Products Company, founded by L.V. Redman. Under director of advertising and public relations Allan Brown, who came to Bakelite from Condensite, Bakelite was aggressively marketed as "The Material of A Thousand Uses."〔 The Bakelite trademark, featuring the letter B above the mathematical symbol for infinity, was filed for as of August 25, 1925, and claimed in use as of December 1, 1924. A wide variety of uses were listed in their trademark applications. The first issue of ''Plastics'' magazine, October 1925, featured Bakelite on its cover, and included the article "Bakelite -- What It Is" by Allan Brown. The range of colors available included "black, brown, red, yellow, green, gray, blue, and blends of two or more of these". The article emphasized that Bakelite came in various forms. "Bakelite is manufactured in several forms to suit varying requirements. In all these forms the fundamental basis is the initial Bakelite resin. This variety includes Clear Material, for jewelry, smokers' articles, etc.; cement, using in sealing electric light bulbs in metal bases; varnishes, for impregnating electric coils, etc.; lacquers, for protecting the surface of hardware; enamels, for giving resistive coating to industrial equipment; Laminated Bakelite, used for silent gears and insulation; and molding material, from which are formed innumerable articles of utility and beauty. The Molding Material is prepared ordinarily by the impregnation of cellulose substances with the initial 'uncured' resin."〔 In a 1925 report, the United States Tariff Commission hailed the commercial manufacture of synthetic phenolic resin as "distinctly an American achievement", and noted that "the publication of figures, however, would be a virtual disclosure of the production of an individual company." In England Bakelite Limited, a merger of three British phenol formaldehyde resin suppliers (Damard Lacquer Company Limited of Birmingham, Mouldensite Limited of Darley Dale and Redmanol Chemical Products Company of London) was formed in 1926. A new Bakelite factory opened in Tyseley, Birmingham, England around 1928. It was demolished in 1998. A new factory was opened in Bound Brook, New Jersey, in 1931.〔 In 1939 the companies were acquired by Union Carbide and Carbon Corporation. Union Carbide's phenolic resin business including the Bakelite and Bakelit registered trademarks are owned by Momentive Specialty Chemicals. In addition to the original Bakelite material, these companies eventually made a wide range of other products, many of which were marketed under the brand name "Bakelite plastics". These included other types of cast phenolic resins similar to Catalin, and urea-formaldehyde resins, which could be made in brighter colors than polyoxybenzylmethylenglycolanhydride.〔 Once Baekeland's heat and pressure patents expired in 1927, Bakelite Corporation faced serious competition from other companies. Because molded Bakelite incorporated fillers to give it strength, it tended to be made in concealing dark colors.〔 In 1927, beads, bangles and earrings were produced by the Catalin Company, through a different process which enabled them to introduce 15 new colors. Translucent jewelry, poker chips and other items made of phenolic resins were introduced in the 1930s or 1940s by the Catalin Company under the Prystal name. The creation of marbled phenolic resins may also be attributable to the Catalin Company. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bakelite」の詳細全文を読む スポンサード リンク
|