Melamine resins, plasticizers

Plastics (polyvinyl acetate, alcohol, chloride, monovinyl acetate, phenolic, urea, and melamine resins, plastics in rods, sheet, and other forms)... 

Since melamine resins are derived from urea, they are more cosdy and are therefore restricted to appHcations requiring superior performance. Essentially ad of the melamine produced is used for making amino resins and plastics. 

Chemical compounds manufactured at petrochemical plants include methanol, formaldehyde, and halogenated hydrocarbons. Formaldehyde is used in the manufacture of plastic resins, including phenolic, urea, and melamine resins. Halogenated hydrocarbons are used in the manufacture of silicone, solvents, refrigerants, and degreasing agents. 

Table 4 Relation between the heat stability of azo pigments in an alkyd-melamine resin baked system, their fastness to overpainting in this paint system, and their bleed resistance in plasticized PVC.

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... 

Another use of urea is for resins, which are used in numerous applications including plastics, adhesives, moldings, laminates, plywood, particleboard, textiles, and coatings. Resins are organic liquid substances exuded from plants that harden on exposure to air. The term now includes numerous synthetically produced resins. Urea resins are thermosetting, which means they harden when heated, often with the aid of a catalyst. The polymerization of urea and formaldehyde produces urea-formaldehyde resins, which is the second most abundant use of urea. Urea is dehydrated to melamine, which, when combined with formaldehyde, produces melamine-formaldehyde resins (Figure 96.2). Melamine resins tend to be harder and more heat-resistant than urea-formaldehyde resins. Melamine received widespread attention as the primary pet food and animal feed contaminant causing numerous cat and dog deaths in early... 

Heat-setting resins cannot be plasticized by low molecular weight plasticizers. Polyvinyl acetals have been claimed for these products. American Cyanamid Co. has suggested polyvinyl acetals or butyrals in an amount of 10 to 25% of the resin for urea and melamine resins. For varnishes and adhesives, combinations of phenolic resins and polyvinyl formal are recommended. Polyvinyl acetals with higher alkyl radicals are suitable for cellulose esters and improve elasticity as well as resistance against water. 

Urea is also used as a protein food supplement for ruminants, in melamine production, and as an ingredient in the manufacture of pharmaceuticals (e.g., barbiturates), synthetic resins, plastics (urethanes), adhesives, coatings, textile antishrink agents, and ion exchange resins. It is an intermediate in the manufacture of ammonium sulfamate, sulfamic acid, and pthalocyanines. 

Plastics can be placed into two main categories, thermoplastic and thermoset. Thermoset plastics are irreversibly formed into a permanent shape often by applying heat. Thermosets caimot be softened and remoulded on heating and have few applications in food packaging, except for the iimer linings used for can coatings and many adhesives, as used, for example, in multilayer materials. A limited range of food contact materials is made from thermosets, predominantly melamine resins and unsaturated polyesters used in tableware and utensils. 

Use Preparation of esters, especially butyl acetate solvent for resins and coatings plasticizers dyeing assistant hydraulic fluids detergent formulations dehydrating agent (by azeotropic distillation) intermediate butylated melamine resins glycol ethers butyl acrylate. 

Micarta [Westinghouse], TM for a group of laminated plastics composed of paper or fabric made from cellulose, glass, asbestos or synthetic fibers bonded with phenolic or melamine resins and cured at elevated temperature and pressure. 

Basotect . [BASF AG] Open-cell resilient foam plastic based on melamine resin used for soundproofing, thermal insulation with firei x)ofing characteristics. 

Basotect , [BASF AG] Opm-cell resil-imit foam plastic based melamine resin used to soundimx g, drermal insulation with fireptooftig character-istks. 

Melamine (2,4,6,-triamino-1,3,5-triazine) is obtained by trimerization of cyanamide or commercially by thermal cyclocondensation of urea at 400°C with elimination of NH3 and CO2. Polycondensation of melamine with formaldehyde produces melamine resins that are used as plastics, glues and adhesives. Cyanuric acid 15 (2,4,6-trihydroxy-1,3,5-triazine) was obtained by Scheele (1776) from pyrolysis of uric acid and was the first 1,3,5-triazine derivative known. Cyanuric acid is synthesized by trimerization of isocyanic acid and is tautomeric with isocyanuric acid 16 ... 

Production of decorated melamine plastic dinner plates makes use of molding and laminating techniques. The pattern is printed on the same type of paper used for the protective overlay of decorative laminates, treated with melamine resin and dried, and then cut into disks of the appropriate size. 

Melamine is a strong organic base, which is used primarily to produce melamine resin, which when combined with formaldehyde produces a very durable thermoset plastic. This plastic is often used in kitchen utensils or plates (often sold under the brand name Melmac), and is the main constituent of Formica and Arborite . Melamine tile wall panels are known as whiteboards. Melamine is also used to make decorative wall panels and is often used as a laminate. Melamine is produced from urea, mainly by either of two methods catalyzed gas-phase production or high-pressure liquid-phase production. 

Figure 8 compares the Tukon hairdness of the melamine and AM 10 films. Films of each material were drawn on primed Bonderite 40 with a 4 blade and cured for 30 minutes at 250° F. Both formulations were catalyzed with 0.8% PTSA on TRS. For the melamine cured films, hardness increases slightly as melamine content is increased from 25 to 40%, but then is reduced at 50% melamine content, probably due to plasticization by unreacted excess melamine functionality. For the acrylated melamine, hardness increases monotonically, probably because of the lower alkoxy functionality and higher Tg of the AM resin compared to the melamine resin. At 40% AM the Tukon hardness is similar to that achieved with a 25% melamine resin. 

C3N3(NH2)3) a white solid organic compound whose molecules consist of a six-membered heterocyclic ring of alternate carbon and nitrogen atoms with three amino groups attached to the carbons. Condensation polymerization with methanal or other aldehydes produces melamine resins, which are important thermosetting plastics. 

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