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Amino resins manufacture

Commercially, urea is produced by the direct dehydration of ammonium carbamate, NH2COONH4, at elevated temperature and pressure. Ammonium carbamate is obtained by direct reaction of ammonia and carbon dioxide. The two reactions are usually carried out simultaneously in a high pressure reactor. Recendy, urea has been used commercially as a catde-feed supplement (see Feeds and feed additives). Other important appHcations are the manufacture of resins (see Amino resins and plastics), glues, solvents, and some medicinals. Urea is classified as a nontoxic compound. [Pg.298]

Amino and Phenolic Resins. The largest use of formaldehyde is in the manufacture of urea—formaldehyde, phenol—formaldehyde, and melamine—formaldehyde resins, accounting for over one-half (51%) of the total demand (115). These resins find use as adhesives for binding wood products that comprise particle board, fiber board, and plywood. Plywood is the largest market for phenol—formaldehyde resins particle board is the largest for urea—formaldehyde resins. Under certain conditions, urea—formaldehyde resins may release formaldehyde that has been alleged to create health or environmental problems (see Amino RESINS AND PLASTICS). [Pg.497]

The commonly used resins in the manufacture of decorative and industrial laminates ate thermosetting materials. Thermosets ate polymers that form cross-linked networks during processing. These three-dimensional molecules ate of essentially infinite size. Theoretically, the entire cured piece could be one giant molecule. The types of thermosets commonly used in laminates ate phenoHcs, amino resins (melamines), polyesters, and epoxies. [Pg.531]

Amino resins are manufactured throughout the industrialized world to provide a wide variety of useful products. Adhesives (qv), representing the largest single market, are used to make plywood, chipboard, and sawdust board. Other types are used to make laminated wood beams, parquet flooring, and for furniture assembly (see Wood-BASED composites and laminates). [Pg.321]

Approximately 25% of the formaldehyde produced in the United States is used in the manufacture of amino resins and plastics. [Pg.323]

In addition to the two main reactions, ie, methylolation and condensation, there are a number of other reactions important for the manufacture and uses of amino resins. For example, two methylo1 groups may combine to produce a dimethylene ether linkage and Hberate a molecule of water ... [Pg.324]

The steps followed in the precure are repeated in the postcure process, except that after the drying step the goods are shipped to a garment manufacturer who makes garments, presses them into the desired shape with creases or pleats, and then cures the amino resin on the completed garment. [Pg.331]

Ammonia is used in the fibers and plastic industry as the source of nitrogen for the production of caprolactam, the monomer for nylon 6. Oxidation of propylene with ammonia gives acrylonitrile (qv), used for the manufacture of acryHc fibers, resins, and elastomers. Hexamethylenetetramine (HMTA), produced from ammonia and formaldehyde, is used in the manufacture of phenoHc thermosetting resins (see Phenolic resins). Toluene 2,4-cHisocyanate (TDI), employed in the production of polyurethane foam, indirectly consumes ammonia because nitric acid is a raw material in the TDI manufacturing process (see Amines Isocyanates). Urea, which is produced from ammonia, is used in the manufacture of urea—formaldehyde synthetic resins (see Amino resins). Melamine is produced by polymerization of dicyanodiamine and high pressure, high temperature pyrolysis of urea, both in the presence of ammonia (see Cyanamides). [Pg.358]

Textiles. Citric acid acts as a buffer in the manufacture of glyoxal resins which are used to give textiles a high quaUty durable-press finish (see Amino resins). It has been reported to increase the soil-release property of cotton with wrinkle-resistant finishes and is used as a buffer, a chelating agent, and a non-volatile acid to adjust pH in disperse dying operations (182—193). [Pg.186]

Uses. Most of the melamine produced is used ia the form of melamiae—formaldehyde resias (see Amino resins and plastics). Other appHcations (63) iaclude the use of melamine pyrophosphate [15541 -60-3] ia fire retardant textile finishes, chloriaated melamine as a bactericide, and melamine as a tarnish inhibitor in detergent compositions, in papermaking, and manufacture of adhesives. [Pg.373]

Formaldehyde is an important chemical in the plastics industry, being a vital intermediate in the manufacture of phenolic and amino resins. It was also used by Reppe during World War II as an important starting point for the preparation of a wide range of organic chemicals. Consumption of formaldehyde in acetal resins is still a minor outlet for the material but exceptionally pure material is required for this purpose. [Pg.532]

By far the bulk of amino resins are used in the woodworking industry for the manufacture of chipboard, plywood and as general glues and adhesives. Melamine-formaldehyde is an important component of decorative laminates. The amount of amino resins used for moulding applications is only of the order of 5% of the total. [Pg.669]

Since cross-linking occurs via an addition mechanism across the double bonds in the polyesters and the reactive diluent there are no volatiles given off during cure (c.f. phenolic and amino-resins) and it is thus possible to cure without pressure (see Figure 25.1). Since room temperature cures are also possible the resins are most useful in the manufacture of large structures such as boats and car bodies. [Pg.696]

Paper laminates, TiCh pigments in, 25 28 Papermaking, 11 179, 287-288. See also Paper manufacture additives in, 15 98 amino resin applications, 2 644-648 asbestos applications, 3 311 calcium carbonate applications, 4 554-555... [Pg.671]

The Food and Drug Administration (1999) permits the use of triethanolamine as a component of adhesives in food packaging as an indirect food additive, as a component of the uncoated or coated food contact surface of paper and paper board for use with dry solid foods with no free fat or oil on the surface, and to adjust pH during the manufacture of amino resins permitted for use as components of paper and paper board in the United States. [Pg.385]

Formaldehyde emission from particleboard has been studied at our laboratory for over 15 years. We search for an answer to the following question Given the fact that amino-resin bonded wood products have the ability to release formaldehyde into indoor air when they are in use, what simple and rapid analysis method can be used at the time of manufacture to predict formaldehyde release under use conditions as quantitatively as possible Obviously, the chosen method needs to be applicable for all types of boards that are available on the market. [Pg.188]

Melamine is used primarily in the manufacture of amino resin. The resin formation reaction is analogous to the urea-formaldehyde system. [Pg.105]

The simple methylol compounds and the low molecular weight polymers obtained from urea and melamine are soluble in water. They are quite suitable for the manufacture of adhesives, molding compounds, and some kinds of textile treating resins. However, amino resins for coating applications require compatibility with the film-forming polymer resins with which they must react. Furthermore, even where compatible, the free methylol compounds are often too reactive and too unstable for use in a coating formulation that may have to be stored for some time before use. Reacting the... [Pg.1106]

Having considered the chemical reactions involved in the preparation of amino resins, a few illustrations will show how these transformations are utilized in the manufacture of molding compounds and coating resins. [Pg.1107]

A troublesome side reaction encountered in the manufacture and use of amino resins is the conversion of formaldehyde to formic acid. Often the reaction mixture of amino compound and formaldehyde must be heated under alkaline conditions. This favors a Cannizzaro reaction in which two molecules of formaldehyde interact to yield one molecule of methanol and one of formic acid. [Pg.325]

Precise control of the course, speed, and extent of the reaction is essential for successful manufacture. Important factors are mole ratio of reactants catalyst (pH of reaction mixture) and reaction time and temperature. Amino resins are usually made by a batch process. The formaldehyde and other reactants are charged to a kettie, the pH adjusted, and the charge heated. Often the pH of the formaldehyde is adjusted before adding the other reactants. Aqueous formaldehyde is most convenient to handle and lowest in cost. [Pg.325]

In general, conditions for the first part of the reaction are selected to favor the formation of methylol compounds. After addition of the reactants, the conditions may be adjusted to control the polymerization. The reaction may be stopped to give a stable symp. This could be an adhesive or laminating resin and might be blended with filler to make a molding compound (see also Laminates Reinforced PLASTICS). It might also be an intermediate for the manufacture of a more complicated product, such as an alkylated amino resin, for use with other polymers in coatings. [Pg.325]

The flow sheet (Fig. 2) illustrates the manufacture of amino resin symps, ceUulose-fiUed molding compounds, and spray-dried resins. [Pg.325]

In the manufacture of amino resins every effort is made to recover and recycle the raw materials. However, there may be some loss of formaldehyde, methanol, or other solvent as tanks and reactors are vented. Some formaldehyde, solvents, and alcohols are also evolved in the curing of paint films and the curing of adhesives and resins appUed to textiles and paper. The amounts of material evolved in curing the resins may be small so that it may be difficult to justify the installation of complex recovery equipment. However, in the development of new resins for coatings and for treating textiles and paper, emphasis is being placed on those compositions that evolve a niinimum of by-products on curing. [Pg.325]

The manufacturing process for partially alkylated amino formaldehyde resins consist of two consecutive reactions. The first reaction is the methylolation (hydroxy-methylation) of an amino compound such as urea, melamine, or benzoguanamine with formaldehyde and can be carried out under basic or acidic conditions. Hydroxy-methylation under acidic conditions leads to simultaneous alkylation and polymerization of the amino resin. The second reaction, alkylation (or etherification), is carried out under acidic conditions. [Pg.82]

Environmental Protection. The potential release of formaldehyde during application and cure is a serious problem in the handling of amino resins. Depending on the structure and the conditions of manufacture a resin can contain 0.25-3% free... [Pg.82]


See other pages where Amino resins manufacture is mentioned: [Pg.120]    [Pg.324]    [Pg.326]    [Pg.333]    [Pg.19]    [Pg.302]    [Pg.10]    [Pg.1109]    [Pg.324]    [Pg.326]    [Pg.333]   


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