Polyacetal resin

Table 5. World Supply/Demand for Polyacetal Resins for 1988 ...

At room temperature there is only a small decrease in free energy on conversion of monomer to polymer. At higher temperatures the magnitude of the free energy change decreases and becomes zero at 127°C above this temperature the thermodynamics indicate that depolymerisation will take place. Thus it is absolutely vital to stabilise the polyacetal resin both internally and externally to form a polymer which is sufficiently stable for processing at the desired elevated temperatures. 

These aspects were discussed in Chapter 9 and further details regarding polyacetal resins may be found from manufacturers, literature and in the various monographs cited at the end of this chapter. 

SITTIG, M., Polyacetal Resins, Gulf Publishing, Houston (1963)... 

Other areas of application include a number of plastics which are processed at elevated temperature. P.R.209 lends color to polyolefins (in which it only slightly affects the shrinkage), to ABS, to polyacetal resins, and other industrial polymers. 

Polyacetal resins have a repeating unit of -O-CH2-. They are strong, stiff polymers for valves, hoses, and tube connectors. Pentaerythritol finds end-uses in alkyd resins and explosives (pentaerythritol tetranitrate). To appreciate this synthesis, the student should review two condensation reactions, the crossed aldol and the crossed Cannizzaro. Acetaldehyde reacts with 3 mol of formaldehyde in three successive aldol condensations. This product then undergoes a Cannizzaro reaction with formaldehyde. 

Masamoto J, Matsuzaki K, Iwaisako T, Yoshida K, Kagawa K, Nagahara H (1993) Development of a new advanced process for manufacturing polyacetal resins. Part 3. End-capping during polymerization for manufacturing acetal homopolymer and copolymer. J Appl Polym Sci 50 1317-1329... 

H. Ome, S. Kumasawa, and J. Kumaki, Poly(lactic acid)/polyacetal resin compositions and heat-resistant high-strength moldings there from with good surface appearance and dimensional stability, Japanese patent 2003342460 A2, assigned to Toray Industries, Inc., December 3, 2003. 

Disinfection by-product) production of urea-formaldehyde, phenolic, melamine, pentaerythritol and polyacetal resins industrial synthesis of a number of organic compounds cosmetics fungicides textiles embalming fluids 3210,322, 351, 3529,354... 

Polyacetal resin compositions having excellent wear resistance were prepared by Kim [4], These resins consisted of polyoxymethylene polymer, ethylene vinylacetate, melamine, triethyleneglycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionate, and hydroxyl pentaerythritol fatty acid ester. 

M. Sittig, Polyacetal Resins, Gulf Publishing Co., Houston, Tex., 1963. 

Among the more than several uses for polyethers in ordn application is as a binder for extrusion-cast expls (Ref 3), and in a caseless proplht charge where the charge is used as an ammo element (Ref 5). Also, some development work on the use of Polyacetal resins (polyformaldehyde) as a fuel has been done by Singhal T ien y[Pg.816]

Use Urea and melamine resins, polyacetal resins, phenolic resins, ethylene glycol, pentaerythritol, hexamethylenetetramine, fertilizer, disinfectant, biocide, embalming fluids, preservative, reducing agent as in recovery of gold and silver, corrosion inhibitor in oil wells, durable-press treatment of textile fabrics, industrial sterilant, treatment of grain smut, foam insulation, particle board, plywood, a versatile chemical intermediate. 

Patent Number US 5478563 A 19951226 ANTIBACTERIAL AND ANTIFUNGAL POLYACETAL RESIN COMPOSITION... 

Antibacterial amd antifungal polyacetal resin compositions include a polyacetal base resin, and an antibacterial and/or antifungal effective amoimt between about 0.1-5 pbw, per 100 pbw of the polyacetal base resin, of at least one antibacterial and antifungal agent which contains a metal ion selection from among silver, copper and zinc ions. JAPAN... 

Polyoxymethylene (POM). Polyoxymethylene can be made from a condensation reaction of polyformaldehyde (DuPont method). Demand for polyacetal has been around 4,600 tons per year [8], The price for polyacetal resin is 1.44 per pound [9],... 

Several papers57"59 were devoted to investigating a complex process such as the cationic copolymerization of monomeric formaldehyde with dioxolane in the gas, liquid, and gas-liquid phases. It is known that polyacetal resins are industrially produced by copolymerizing cyclic acetals (trioxane, 1,3,5,7-tetraoxane), or by anionic homopolymerization of monomeric formaldehyde with subsequent modification of end groups. 

Polyfine . [Advanced Web Prods.] Thermoplastic resins economical substitute to polyacetal resin in q)plics. where friction and wear props, are required for VTR U )e reel, noiseless gear, bearing surface. 

The TG-MS of a polyacetal resin is shown in Figure 8.71 (149). The TG curve indicated two mass-loss steps involving 75 and 21%, respectively. MS of the two cuts corresponding to the two mass-loss steps showed mainly formaldehyde for the first cut and tetrafluoroethylene for the second cut. Since polyoxymethylene and polytetrafiuoroethylene are known to de-polymerize almost completely into their respective monomers, the resin part probably consists of 75% of the former and 21% of the latter by weight. 

OTHER COMMENTS used in the production of amino, phenolic, and polyacetal resins used in the manufacture of wood products, plastics, fertilizers and foam insulation used as a preservative, disinfectant and antibacterial food additive. 

The ultramarines range in color from a medium shade blue through violet to pink. A household example of an ultramarine blue in full shade is the Milk of Magnesia bottle. Standard grades of ultramarine pigments (uncoated) react with polyacetal resins, and I have observed color drift of these pigments in PC and PA 6/6. Some properties of ultramarine pigments are listed in Table 1. 

MAJOR APPLICATION Thermal stabilizer for polyoxymethylene, and stabilizer for polyacetal resin. Because of high amide concentration, nylon 3 shows properties of an excellent formaldehyde scavenger. 

Synonyms Acetal resin Polyacetal Polyacetal copolymer Polyacetal resin Polyfonnaldehyde Polyot methylene copolymer POM Classification Thermoplastic polymer... 

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