POM Asahi Kasei 4590

POM Asahi Kasei 4590（TENAC‑C 4590）

POM Asahi Kasei 4590 is a widely‑used copolymer‑acetal engineering plastic with balanced comprehensive properties. It fits applications requiring good stiffness, wear‑resistance, dimensional stability and chemical‑resistance. Its FDA food‑contact certification enables its adoption in special‑purpose fields。

Main Applications

Automotive: gears, bearings, fuel‑system components, interior & exterior door handles, crank‑type window transmission mechanisms, oil‑pump bearing seats, impellers and pipeline valves. Electrical & electronic: washing‑machine and juicer components, timer assemblies, keyboards, switch parts, bearings for audio‑video tapes. Precision machinery & industrial components: gears, bearings, cams, screws, levers, pulleys, sprockets and engineering fittings. Consumer & others: zippers, lighters, buckles, toys, sports‑equipment and thermostats. Especially suitable for food‑contact applications。

Physical & Mechanical Properties

Property Category	Item	Test Standard	Typical Data	Unit
Physical Properties	Density	ISO 1183	1.41	g/cm³
	Water absorption (24 h immersion)	—	0.2‑0.5	%
	MFR (190 ℃ / 2.16 kg)	ISO 1133	9.0	g/10min
	Molding shrinkage	—	1.6‑2.0	%
Mechanical Properties	Tensile yield strength	ISO 527‑1/-2	66	MPa
	Elongation at break	ISO 527‑1/-2	55	%
	Tensile modulus	ISO 527‑1/-2	2800	MPa
	Charpy notched impact strength (23 ℃)	ISO 179/1eA	7	kJ/m²
Thermal Properties	HDT (1.8 MPa)	ISO 75‑1/-2	100	℃
	HDT (0.45 MPa)	ISO 75‑1/-2	156	℃
Flammability	UL94 rating	UL 94	HB	—

Injection Molding Parameters

Process Stage	Parameter	Recommended Range	Unit	Remarks
Pre‑drying	Drying temperature	80‑90	℃	Drying is recommended for damp raw materials to stabilize production and surface quality, avoid bubbles or silver streaks, despite low moisture absorption.
	Drying time	2‑4	h
Barrel temperature	Rear zone	150‑180	℃	POM has narrow processing window; do not exceed 230 ℃, otherwise formaldehyde gas will be generated by thermal decomposition.
	Middle zone	170‑190	℃
	Front zone	180‑200	℃
	Nozzle temperature	Slightly lower than front‑zone temperature	℃	Prevent drooling.
	Melt temperature (POM‑C, copolymer)	190‑210	℃
	Mold temperature	＞60 (80‑90 preferred)	℃	Higher mold temperature improves crystallization, dimensional stability, surface gloss and reduces sink marks.
Injection parameters	Injection pressure	40‑130	MPa	Higher for thin‑wall parts; lower for thick‑wall parts.
	Hold‑up pressure	Close to injection pressure	MPa	Relatively high hold‑pressure to reduce pressure drop and sink marks.
	Back pressure	0.5‑2.0	MPa	Keep as low as possible; excessive back‑pressure causes thermal‑shear degradation.
	Injection speed	Medium	—	Slow speed causes flow marks; excessive speed induces jetting and shear degradation.
	Screw speed	50‑100	rpm	Avoid high rotational speed to prevent excessive shear heat and material degradation.
	Barrel residence time	As short as possible (<20‑30)	min	Prevent thermal decomposition; do NOT exceed 1 h at 190 ℃.
Shutdown procedure	Short‑term shutdown	Drop barrel temperature to 150	℃	Thoroughly purge barrel for long‑term shutdown.
	Barrel purging material	PE / PP	—	Turn off heating, clean barrel and screw. Avoid copper components contacting POM melt, copper accelerates POM degradation.
Post‑treatment	Annealing (if required)	120‑130 ℃, air or oil bath	—	Relieve internal stress for high‑precision or non‑ambient‑service parts. Approx. 10 min per mm wall‑thickness.

Note: All data above is for reference only！