Bakelite
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Bakelite (pronounced /ˈbeɪkɨlaɪt/), or polyoxybenzylmethylenglycolanhydride, is an early plastic. It is a thermosetting phenol formaldehyde resin, formed from an elimination reaction of phenol with formaldehyde, usually with a wood flour filler. It was developed in 1907–1909 by Belgian chemist Dr. Leo Baekeland.
One of the first plastics made from synthetic components (although phenol can be extracted from biological sources), Bakelite was used for its electrically nonconductive and heat-resistant properties in radio and telephone casings and electrical insulators, and also in such diverse products as kitchenware, jewellery, pipe stems, and children's toys. In 1993 Bakelite was designated an ACS National Historical Chemical Landmark in recognition of its significance as the world's first synthetic plastic.[1]
The "retro" appeal of old Bakelite products and labor intensive manufacturing has made them quite collectible in recent years.
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[edit] History
Dr. Baekeland had originally set out to find a replacement for shellac (made from the excretion of lac beetles). Chemists had begun to recognize that many natural resins and fibers were polymers, and Baekeland investigated the reactions of phenol and formaldehyde. He first produced a soluble phenol-formaldehyde shellac called "Novolak" that never became a market success, then turned to developing a binder for asbestos which, at that time, was moulded with rubber. By controlling the pressure and temperature applied to phenol and formaldehyde, he found he could produce his dreamed-of hard mouldable plastic: bakelite.[2]
The Bakelite Corporation was formed in 1922 (after patent litigation favorable to Baekeland) from a merger of three companies: the General Bakelite Company, which Baekeland had founded in 1910, the Condensite Company founded by J.W. Aylesworth, and the Redmanol Chemical Products Company founded by L.V. Redman.[3]
The Catalin Corporation of America acquired the Bakelite formulas in 1927.
Bakelite Limited was formed in 1926 from the amalgamation of three suppliers of phenol formaldehyde materials: the Damard Lacquer Company Limited of Birmingham; Mouldensite Limited of Darley Dale and Redmanol Chemical Products Company of London. Around 1928 a new factory opened in Tyseley, Birmingham, England (subsequently demolished in 1998). In 1939 the company was acquired by the Union Carbide and Carbon Corporation.
[edit] Properties
Phenolics are seldom used in general consumer products today due to the cost and complexity of production and their brittle nature. An exception to this overall decline is their use in small precision-shaped components where their specific properties are required, such as molded disc brake cylinders, saucepan handles, electrical plugs and switches and parts for electrical irons. Today, Bakelite is manufactured and produced in sheet, rod and tube form for hundreds of industrial applications in the electronics, power generation and aerospace industries, and under a variety of commercial brand names, including Garolite.
Phenolic sheet is a hard, dense material made by applying heat and pressure to layers of paper or glass cloth impregnated with synthetic resin. These layers of laminations are usually of cellulose paper, cotton fabrics, synthetic yarn fabrics, glass fabrics or unwoven fabrics. When heat and pressure are applied to the layers, a chemical reaction (polymerization) transforms the layers into a high-pressure thermosetting industrial laminated plastic. When rubbed, original Bakelite has a telltale odor.
Bakelite Phenolic is produced in dozens of commercial grades and with various additives to meet diverse mechanical, electrical and thermal requirements. Some common types include:
- PAPER REINFORCED PHENOLIC NEMA XX per MIL-I-24768 PBG Normal electrical applications, moderate mechanical strength, continuous operating temperature of 250°F.
- CANVAS REINFORCED PHENOLIC NEMA C per MIL-I-24768 TYPE FBM NEMA CE per MIL-I-24768 TYPE FBG Good mechanical and impact strength with continuous operating temperature of 250°F.
- LINEN REINFORCED PHENOLIC NEMA L per MIL-I-24768 TYPE FBI NEMA LE per MIL-I-24768 TYPE FEI Good mechanical and electrical strength. Recommended for intricate high strength parts. Continuous operating temperature 250°F.
- NYLON REINFORCED PHENOLIC NEMA N-1 per MIL-I-24768 TYPE NPG Superior electrical properties under humid conditions, fungus resistant, continuous operating temperature of 160°F.
[edit] Applications and usage
Although no longer extensively used as an industrial manufacturing material, Bakelite was used in myriad applications including saxophone mouthpieces, whistles, cameras, solid-body electric guitars, rotary-dial telephones, early machine guns, and appliance casings. The thermosetting plastic was at one point considered for the manufacture of coins, due to a shortage of traditional manufacturing material. In 1943, Bakelite and other non-metal materials were tested for usage as a penny in the United States before the Mint settled on zinc coated steel.[4][5]
Bakelite was used widely from the late 1920s and throughout the 1930s for jewelry. Huge quantities of beads, bangles and earrings were produced by the Catalin Company which introduced 15 new colours in 1927, and created marbled and translucent plastics. The jewelry of this era is now highly collectable. It was no longer made after the second world war due to expensive production costs. Jewelry boxes, desk sets, clocks, radios, kitchenware such as canisters and tableware were also made of Bakelite during the 1930s.
The foremost usage of Bakelite today is as a substitute for porcelain and other opaque ceramics in applications where fine detail is unimportant (other thermoset resins can capture detail more finely when molded) and durability over traditional ceramic compounds is desired. As such, a main continuing use for Bakelite is in the area of board and tabletop games. Devices such as billiard balls, dominoes, Mahjongg tiles and other gaming tilesets, and movers/pieces for games like chess, checkers, and backgammon are constructed of Bakelite for the look, durability, fine polish, weight, and sound of the resulting pieces. Dice are sometimes made of Bakelite for weight and sound, but the majority are made of a thermoplastic such as ABS. Bakelite is used to make the presentation boxes of Breitling watches and sometimes as a substitute for metal firearm magazines. It also saw extensive use in Soviet military firearm grips.
Bakelite is also used in the mounting of metal samples in metallography.[6]
Phenolic resins have been commonly used in ablative heat shields. Soviet heatshields for ICBM warheads and spacecraft reentry consisted of asbestos textolite impregnated with Bakelite.[7]
[edit] Patents
[edit] See also
- Ansco Panda – children's Bakelite box camera
- Bayko – A construction set toy in which most of the parts were made of Bakelite
- Catalin
- Galalith - another early plastic, derived from milk
- Novotext
- Phenol formaldehyde resin
- Phenolic resin
[edit] References
- ^ New Products
- ^ Amato, Ivan (29 March 1999). "Leo Baekeland". Time 100. TIME. http://www.time.com/time/time100/scientist/profile/baekeland.html.
- ^ American Institute of Chemical Engineers Staff (1977). Twenty-Five Years of Chemical Engineering Progress. Ayer Publishing. pp. 216. ISBN 0836901495.
- ^ J2051/P2073 USPatterns.com. Accessed July 28, 2006
- ^ The New Yorker. Penny Dreadful. David Owen. March 31, 2008.
- ^ http://www.grc.nasa.gov/WWW/StructuresMaterials/ASG/MetLab/mounting.html
- ^ Roads to Space: an oral history of the Soviet space program
