15mm Polyacetal POM Plastic Plate

Description:

Polyoxymethylene (POM), also known as acetal, polyacetal and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and sold variously .

POM is characterized by its high strength, hardness and rigidity to −40 °C. POM is intrinsically opaque white, due to its high crystalline composition, but it is available in all colors. POM has a density of 1.410–1.420 g/cm3.

Typical applications for injection-molded POM include high-performance engineering components such as small gear wheels, eyeglass frames, ball bearings, ski bindings, fasteners, guns, knife handles, and lock systems. The material is widely used in the automotive and consumer electronics industry.

Production:

Different manufacturing processes are used to produce the homopolymer and copolymer versions of POM.

• Homopolymer

To make polyoxymethylene homopolymer, anhydrous formaldehyde must be generated. The principal method is by reaction of the aqueous formaldehyde with an alcohol to create a hemiformal, dehydration of the hemiformal/water mixture (either by extraction or vacuum distillation) and release of the formaldehyde by heating the hemiformal. The formaldehyde is then polymerized by anionic catalysis and the resulting polymer stabilized by reaction with acetic anhydride. Due to the manufacturing process, large diameter cross sections may have pronounced centerline porosity. 

• Copolymer

The polyoxymethylene copolymer replaces about 1–1.5% of the –CH2O– groups with –CH2CH2O–.

To make polyoxymethylene copolymer, formaldehyde is generally converted to trioxane (specifically 1,3,5-trioxane, also known as trioxin). This is done by acid catalysis (either sulfuric acid or acidic ion exchange resins) followed by purification of the trioxane by distillation and/or extraction to remove water and other active hydrogen containing impurities. Typical copolymers are Hostaform from Celanese and Ultraform from BASF.

The co-monomer is typically dioxolane but ethylene oxide can also be used. Dioxolane is formed by reaction of ethylene glycol with aqueous formaldehyde over an acid catalyst. Other diols can also be used.

Trioxane and Dioxolane are polymerized using an acid catalyst, often boron trifluoride etherate, BF3 OEt2. The polymerization can take place in a non-polar solvent (in which case the polymer forms as a slurry) or in neat trioxane (e.g. in an extruder). After polymerization, the acidic catalyst must be deactivated and the polymer stabilized by melt or solution hydrolysis to remove unstable end Stable polymer is melt compounded, adding thermal and oxidative stabilizers and optionally lubricants and miscellaneous fillers.

Usage:

• Mechanical gears, sliding and guiding elements, housing parts, springs, chains, screws, nuts, fan wheels, pump parts, valve bodies.
• Electrical engineering: insulators, bobbins, connectors, parts for electronic devices such as televisions, telephones, etc.
• Vehicle: fuel sender unit, Light/Control stalk/Combination Switch (including shifter for light, turn signal), power windows, door lock systems, articulated shells.
• Model: model railway parts, such as trucks (bogies) and hand rails (handle bars). POM is tougher than ABS, comes in bright translucent colors, and is not paintable.
• Food industry: Food and Drug Administration has approved some grades of POM for milk pumps, coffee spigots, filter housings and food conveyors.
• Furniture: hardware, locks, handles, hinges.
• Dining: fully automatic coffee brewers; knife handles (particularly folding knives).

Related data:

1. Regular packing, protected by pallet.

2. Depending on the requirement of customers.