Amino plastics

The term amino resin is usually appHed to the broad class of materials regardless of appHcation, whereas the term aminoplast or sometimes amino plastic is more commonly appHed to thermosetting molding compounds based on amino resins. Amino plastics and resins have been in use since the 1920s. Compared to other segments of the plastics industry, they are mature products, and their growth rate is only about half of that of the plastics industry as a whole. They account for about 3% of the United States plastics and resins production. 

Allyl plastics Amino plastics Anneal Assembly... 

Amino plastics Group of plastics generated by the condensation of amines (e.g. urea and melamine with aldehydes). 

Aminos. There are two basic types of amino plastics - urea formaldehyde and melamine formaldehyde. They are hard, rigid materials with good abrasion resistance and their mechanical characteristics are sufficiently good for continuous use at moderate temperatures (up to 100°C). Urea formaldehyde is relatively inexpensive but moisture absorption can result in poor dimensional stability. It is generally used for bottle caps, electrical switches, plugs, utensil handles and trays. Melamine formaldehyde has lower water absorption and improved temperature and chemical resistance. It is typically used for tableware, laminated worktops and electrical fittings. 

Highly cross-linked condensation materials form the basis for a number of important adhesives and bulk materials, especially phenolic and amino plastics. Most of these products have formaldehyde as one of their starting reactants. These materials are thermosets that decompose prior to melting, and are therefore more difficult to recycle than most condensation polymers that are thermoplastics and do melt prior to decomposition. 

The amino resins or plastics, closely related to the phenolics in both synthesis and applications, are obtained by the polymerization of formaldehyde with urea (XXXVII) (/ = 4) or melamine (XXXVIII) (f — 6). Synthesis of the amino plastics can be carried out either in alkaline or acidic conditions [Drumm and LeBlanc, 1972 Nair and Francis, 1983 Updegraff, 1985]. Control of the extent of reaction is achieved by pH and temperature control. The prepolymer can be made at various pH levels depending on the reaction temperature chosen. Polymerization is stopped by cooling and bringing the pH close to neutral. Curing of the prepolymer involves heating, usually in the presence of an added acid catalyst. 

The United States production of amino plastics was more than 3 billion pounds in 2001. The urea-formadehyde polymers account for slightly more than 85% of the total. The amino plastics are similar in properties to the phenolics but are clearer and colorless. They are also harder but have somewhat lower impact strength and resistance to heat and moisture. The melamine resins are better than the ureas in hardness and resistance to heat and moisture. The melamine and urea resins are rated for continuous use at temperatures of 130-150°C and 100°C, respectively. The general applications of the amino and phenolic plastics are the same but there are uses where the amino plastics are superior. The melamine resins find an important niche due to their combination of clarity and lack of color compared to the phenolics and their superior hardness and heat and moisture resistance compared to... 

Synthetic Resin Adhesives for Plywood (Phenolic and Amino plastic), 1945. 

Consequently the graph beyond the peak is probably of little relevance, while stopping the instrument earlier and not emptying it extremely quickly could result in very difficult to remove blocks of hard plastic. ASTM D3795 lists head temperatures for eight different materials, including two temperatures for cross-linkable polyethylene, epoxy, and phenolic. Amino plastics are not in the list, although this type of instrument can be used for the.se materials as described by Paul [62]. 

Synthetic thermosets which cure on heating to solids, e.g., amino plastics, epoxides, phenolic resins, unsaturated polyesters, polyaromatics, and furanes. 

Britain, amino-plastics and Bakelite were responsible for the major part of consumption, with the result that [t]he plastics industry is one of the largest users of formaldehyde. The source of formaldehyde was methanol This was of course formerly obtained from the destructive distillation of wood, but is now produced synthetically from [the high pressure reaction between] carbon monoxide and hydrogen. In 1939, the main producers of formaldehyde for the plastics industry were Synthite Ltd., of West Bromwich, and B.N.R. Ltd., of Barking, Essex (whose selling agent was Victor Blagden Co. Ltd.). 

Amino plastics urea-, thiourea- and melamine-formaldehyde products... 

Polyamides Polyurethanes Polyureas Amino-plastics Polyacrylonitrile and copolymers Polyvinyl-carbazole Polyvinylpyrrolidone... 

There are two basic types of amino plastics - urea formaldehyde (UF) and melamine formaldehyde (MF). Both are hard, rigid materials with good abrasion resistance and mechanical characteristics for their continuous use at moderate temperatures (up... 

Phenolic molding scrap is accepted back by some producers for re-use as filler in new compounds. Similarly, amino plastics (urea and melamine) present no problems in disposal or re-use when ground up. Molders have reused as much as 20 AVt% ground scrap with virgin molding compounds in injection molding and those who have adopted the technique have foimd it an effective method for recycling in-house scrap, but for sub-surface parts only. 

Amino plastics. Collective term for amino resin based plastics. Amino resins are manufactured by condensation of an amine compound such as urea or melamine with... 

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