Wear resistance polyacetals

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. 

Wear resistance of the polyacetal-metal friction pair can be improved considerably by the introduction of higher fat acids or realizing their S3mthesis conditions in the friction zone. Passivation of metal surface layers by phos-phating formulations and epilamens may elevate wear resistance of friction bodies in which polyacetal, polyamide, fluoroplastics, and other substances rub against copper alloys, aluminum, chrome or titanium [108,117,118]. 

Polyacetals are engineering plastics because of their high hardness, rigidity and tensile strength, good abrasion and wear resistance, and favorable low frictional properties, all of which are advantages over other materials. Since polyacetals absorb virtually no water, they have excellent weight retention characteristics. Polyacetals only dissolve in hexafluoroacetone hydrate at... 

Both the matrix and the filler contribute to wear resistance. Typical polymers used in these applications include polyamide, polyacetal, polybutene terephthalate, and polycarbonate. These polymers have the right balance of required properties,... 

A comparison of the abrasive wear by Bohm (1990) found that the hard and more brittle plastics, such as polyacetals, polyamide-imide, and polycarbonates, are less abrasion resistant than softer and tougher materials such as the polyethylenes and polyurethanes. Table 7.2 details some comparative... 

Polyacetals, as distinct from polyformaldehyde, have not been exploited to their fullest potential as other polymers have and much research still remains to be done [17]. Some typical uses are as prepolymers for polyurethane elastomers [18, 19], in dimensional stabilization of cellulosic fabrics [20], paper [21], and segmented cellulose films [21] as synethetic lubricants [22] as coatings for wire [23] as wash-and-wear finishes [24], in solvent-resistant coatings [25] and in castings, laminates, coatings [13, 26], and varnishes [27]. 

Some of the main applications for POM in electrical systems include mountings and brackets for lamp reflectors, gear trains for helical window lift gears, interior input control switches such as multi-function turn signal switches and master light control units, seat adjustment systems, climate control systems and door lock systems. Polyacetals are particularly valued in these applications for their chemical and high temperature resistance, dimensional stability and low wear and friction (gear trains). 

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