The difference of POM-C and POM-H
2025-04-22
The difference of POM-C and POM-H
Polyoxymethylene material, also known as POM or acetal, is a commonly used engineering plastic, often used in humid environments. The remarkable characteristics of POM materials are the dimensional stability of the finished product and low water absorption. Due to its good dimensional stability and fatigue resistance, polyoxymethylene POM material has a high market share in precision parts and engineering materials with small tolerance requirements.
But at the same time, POM materials also have their corresponding defects, such as
- General heat resistance. If used continuously in an environment of 80-100℃, the structure will be damaged or decomposed;
- Not resistant to acid and heat, and will decompose when used under high temperature or acidic conditions;
- Poor UV resistance and is prone to aging during long-term outdoor use;
- Difficult to adhere and paint. Due to its strong surface inertness, polyoxymethylene products are not easy to paint and adhere
Click to learn more ➡️POM material
1. Basic Concepts of POM-C and POM-H
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What is POM-H (homopolymer)?
The polymer chain of POM-H contains only one repeating unit, -CH2-O-. The molecular chain of this material is very neat, which makes the material more crystalline and has excellent mechanical properties. However, the regular structural properties make POM-H less impact-resistant. The material is brittle and prone to structural fracture when subjected to external impact.
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What is POM-C (copolymer)?
Copolymerized oxymethylene, also known as POM-C, is a new polymer material formed by introducing copolymerized monomer materials of other structures on the basis of formaldehyde-based monomers.
The POM-C material after copolymerization changes the neat molecular structure of the POM-H material. The molecular chain structure is irregular, the crystallization performance is poor, and the material strength and rigidity performance are reduced, but the material's high temperature resistance, hydrolysis resistance and structural stability are improved.
The POM-C material after copolymerization changes the neat molecular structure of the POM-H material. The molecular chain structure is irregular, the crystallization performance is poor, and the material strength and rigidity performance are reduced, but the material's high temperature resistance, hydrolysis resistance and structural stability are improved.
2. Performance Differences between POM-C and POM-H
|
Performance
|
POM-H（Homopolymer）
|
POM-C（Acetal copolymer）
|
|---|---|---|
|
Mechanical strength
|
High
|
Low
|
|
Wear resistance
|
Excellent |
Good
|
|
Chemical resistance
|
Generally
|
Stronger,
better acid and alkali resistance than POM-H
|
|
Thermal stability
|
High melting point
|
Low melting point,
but resistant to hot water
|
|
Water absorbency
|
Low
|
High
|
|
Processing stability
|
Narrow processing window
|
Easy to process
|
|
Surface gloss
|
High
|
Low
|
3. Difference between POM-C and POM-H in appearance
The appearance of copolymer and homopolymer is not very different. In the natural state (no filling, no coloring), there is a small difference in appearance.
- POM-H is usually pure white or translucent, with high gloss, and the cross section of the profile is smooth and crisp.
- POM-C is milky white, with slightly lower surface gloss and soft luster, and the cross section is delicate and smooth.
The cross section of POM-H is rougher than that of POM-C
4. Difference between POM-C and POM-H in application
POM-H (Homopolymer material) is more suitable for:
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Parts with high rigidity and dimensional accuracy requirements;
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Gears, bushings, etc. with high self-lubrication requirements;
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Mechanical structural parts with high strength and wear resistance requirements;
Application examples:
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Precision mechanical parts
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Gears, cams
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Slide rails, bearing seats
⚠️ Note that it has poor hydrolysis resistance and is not recommended for long-term use in humid or high-temperature water environments.
POM-C (Acetal copolymer) is more suitable for:
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Environments that require better hydrolysis resistance and chemical resistance;
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Food contact, medical equipment, etc. have higher requirements for cleanliness and stability;
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Parts that require better impact toughness and stronger thermal stability;
Application examples:
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Fluid transport parts (such as valves, pump housings)
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Food industry equipment parts
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Medical equipment, analytical instrument parts
5. Major POM material manufacturer
Click on the company name for more information
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Company
|
Country | Brand |
Types
|
|---|---|---|---|
|
U.S.A
|
Delrin
|
POM-H
|
|
| U.S.A |
Hostaform®, Celcon
|
POM-C
|
|
| Japan |
DURACON
|
POM-H / POM-C
|
|
|
Kolon Plastics
|
Korea |
Kocetal
|
POM-H / POM-C
|
| China |
Yuntianhua
|
POM-H
|
Luoyang Baiyou - as a POM distributor with over 20 years of experience, we recommend the following POM resins
TENAC 3010 is a formaldehyde copolymer material manufactured by Asahi Kasei Corporation. It offers excellent lubricating properties and is commonly used in the production of mechanical components, including low-friction parts for automobiles. The material has been approved by numerous automakers, including BMW, Bosch, Ford, Daimler, and Volkswagen, and is widely used in their automotive products.
Asahi Kasei has a melt flow index (MFI or MVR) of 2.8 g/10 min under test conditions of 190°C and 2.16 kg, making it suitable for injection molding. It has moderate viscosity and is relatively easy to process.
Introduction for POM Polyplastics M90-44