Polyacetal (POM), also known as polyoxymethylene or acetal resin, is a high-performance engineering thermoplastic renowned for its superior mechanical strength, excellent wear resistance, and dimensional stability across various industries.
Available in granule or powder form, this material offers low friction, high chemical resistance, and reliable performance across a temperature range of -40°C to 100°C, making it an ideal choice for producing precise, durable components in automotive, electronics, industrial equipment, and household appliances.
Tolymer Group supplies high-quality polyacetal in various grades, meeting market demands with a focus on optimal performance and sustainability.
This polymer adds significant value to final products through its durability and high efficiency.
Polyacetal’s unique combination of mechanical, chemical, and thermal properties makes it a key material for manufacturing high-precision engineering components. With metal-like strength, low friction, and fatigue resistance, it serves as a cost-effective alternative to traditional materials like steel and aluminum in industrial applications.
Applications of polyacetal include:
Polyacetal enhances component efficiency, reduces maintenance costs, and extends product lifespan, enabling manufacturers to produce competitive, high-quality products.
These components enhance vehicle performance and reduce maintenance needs.
These components ensure long-term performance and stability in harsh industrial environments.
Example:
Dishwasher switches with smooth operation and high safety.
These products are designed for everyday applications.
These components deliver reliable performance and long service life in industrial and domestic systems.
Polyacetal’s outstanding engineering properties make it an ideal choice for precise, high-performance applications. Its benefits support manufacturers in producing high-quality products:
High Mechanical Strength:
With an elastic modulus up to 3,200 MPa and tensile strength up to 70 MPa, polyacetal is a viable metal replacement for components like gears and bearings, reducing product weight.
Low Friction and Wear Resistance:
A low friction coefficient (0.1 to 0.3) and high wear resistance make it ideal for moving parts like rails and bearings, reducing lubrication needs by up to 50%.
Excellent Dimensional Stability:
Low shrinkage (1-2%) and creep resistance ensure suitability for precision components like connectors and valves, even at -40°C to 100°C.
Chemical Resistance:
Resistance to fuels, oils, and organic solvents makes it suitable for automotive fuel systems and industrial pumps, enhancing durability in chemical environments.
Optimal Processability:
A melt flow index (MFI) of 5 to 30 g/10 min and moderate processing temperature (180°C to 220°C) enable fast, precise production via injection molding and extrusion.
Electrical Insulation:
High electrical resistance (up to 10¹⁴ ohm-m) ensures safety in electronic components like connectors and switches.
Fatigue Resistance:
Excellent resistance to dynamic loads makes it suitable for components like gears and plastic springs under constant stress.
Smooth, High-Quality Finish:
A polished surface and colorability make it ideal for consumer products like zippers and locks requiring an attractive appearance.
Despite its numerous advantages, polyacetal has limitations that manufacturers should consider:
Limited UV Resistance:
Without UV stabilizers, polyacetal degrades under sunlight, affecting color and mechanical properties. UV-resistant grades increase costs by up to 20%.
Sensitivity to Strong Acids and Bases:
Polyacetal has low resistance to strong acids (e.g., sulfuric acid) and bases, limiting use in specific chemical environments like chemical plants.
Higher Cost Compared to Commodity Polymers:
Polyacetal is up to twice as expensive as polyethylene or polypropylene, potentially limiting its use in cost-sensitive applications like packaging.
Limited Moisture Absorption:
Moisture absorption of 0.2% to 0.5% in humid environments may cause minor changes in mechanical properties, especially in homopolymer grades.
Flammability:
Without flame-retardant additives, polyacetal is flammable, requiring modifications for fire-safety applications, which increase costs.
Poor Additive Dispersion:
In reinforced grades with glass fiber, inadequate dispersion may reduce strength or cause surface defects, particularly in non-standard production processes.
Limited Service Temperature:
Polyacetal (especially homopolymer) may lose properties above 100°C, restricting use in high-temperature applications like engine components.
Recycling Challenges:
Due to its crystalline structure and specialized additives, recycling polyacetal is more complex than commodity polymers, posing challenges in industries prioritizing sustainability, such as packaging.
Proper storage of polyacetal is essential to maintain its mechanical, chemical, and processing properties. Improper conditions can lead to moisture absorption, additive degradation, or changes in physical properties:
Temperature:
Store at 15°C to 25°C to prevent additive degradation or granule sticking. Temperatures above 30°C may weaken stabilizers, while below 5°C, brittleness may increase.
Moisture Protection:
Moisture levels above 0.2% can cause surface defects during production. Use laminated bags with a polyethylene layer (100-micron thickness) or sealed containers to keep moisture below 0.2%. Warehouses should have dehumidifiers.
UV Protection:
UV light degrades polymer chains. Store in enclosed spaces using opaque bags or protective covers.
Proper Stacking:
Stack bags on dry, flat pallets with a maximum height of five bags to prevent pressure and deformation. Maintain a 50 cm gap between pallets for ventilation and access.
Periodic Checks:
Regularly monitor temperature, humidity, and bag conditions for tears or leaks. Use a first-in, first-out (FIFO) system to prevent quality degradation.
Proper packaging and transportation ensure polyacetal quality and prevent contamination or physical damage:
Robust Packaging:
Use 25 kg laminated bags with a 100-micron polyethylene inner layer to protect against moisture and dust. Big bags (500-1,000 kg) with discharge valves are available for large orders.
Accurate Labeling:
Durable labels with safety information (e.g., “Keep away from moisture and heat”) and technical details (product name, weight, batch number) per ISO 780 standards.
Safe Transportation:
Use well-ventilated, clean vehicles to avoid heat and contamination. Cooling containers (below 30°C) are recommended for hot seasons.
Load Stability:
Symmetrical bag stacking with secure straps and stretch film. Use standard pallets with a 1,000 kg capacity for stability.
Compliance:
Transport per ADR regulations, providing safety data sheets (MSDS) and quality certificates for customs compliance.
Manufacturing with polyacetal may encounter challenges that must be addressed for product quality:
– Thermal Degradation: Processing temperatures above 220°C can produce formaldehyde gas. Maintaining temperatures between 180°C and 220°C and using thermal stabilizers mitigates this.
– Inadequate Melt Flow: High viscosity can cause incomplete mold filling or surface defects. Selecting a grade with an appropriate MFI (5-30 g/10 min) and adjusting injection speed resolves this.
– Moisture Absorption: Moisture above 0.2% can cause bubbles or surface defects. Drying granules (80°C for 2-3 hours) before processing is essential.
– Gas Release: Formaldehyde gas at high temperatures is hazardous. Strong ventilation systems and adherence to recommended temperatures minimize this risk.
– Poor Additive Dispersion: In reinforced grades, inadequate dispersion reduces strength. High-speed mixers and quality control of raw materials address this.
– Unexpected Shrinkage: Excessive shrinkage in thick parts due to uneven cooling can occur. Proper mold design and cooling temperature control reduce this issue.
Selecting high-quality polyacetal is critical for producing precise components:
Grade Type:
Homopolymer for rigidity, copolymer for chemical resistance, and reinforced grades for high strength. Match the grade to the application (e.g., automotive or electronics).
Mechanical Properties:
Verify tensile strength (minimum 60 MPa), elastic modulus (minimum 2,500 MPa), and wear resistance. Request supplier technical reports.
Moisture Content:
Ensure moisture below 0.2% to avoid defects. Request moisture test reports.
Melt Flow Index (MFI):
MFI between 5 and 30 g/10 min for optimal processability. Higher MFI grades are suitable for thin parts.
Safety Certifications:
Ensure compliance with FDA, REACH, or RoHS standards for sensitive applications. Verify the absence of harmful substances.
Environmental Resistance:
UV-resistant grades for outdoor use. Request test reports (e.g., ASTM G154).
Additive Quality:
Ensure uniform dispersion in reinforced grades. Test samples are recommended for quality evaluation.
Similarities:
All are thermoplastics used for plastic components via molding and extrusion. Both are used in packaging and industrial parts.
Differences:
Polyacetal offers superior mechanical strength, low friction, and dimensional stability but is more expensive. PE and PP are more flexible, cheaper, and suited for general applications like bags and containers.
Polyacetal Advantage: Metal-like strength, low friction for moving parts, and fatigue resistance for engineering applications like gears.
Limitation:
Higher cost (up to twice as much) and lower resistance to strong acids compared to PP, which is more chemically resistant.
Similarities:
Both are engineering polymers with high strength, used for precision parts and packaging. Both support injection molding.
Differences:
PET is better for transparent packaging (e.g., bottles) and has superior chemical resistance, while polyacetal excels in low-friction engineering components like bearings.
Polyacetal Advantage:
Low friction, dimensional stability, and fatigue resistance for moving and precise parts.
Limitation:
Lack of transparency and higher cost compared to PET, which is more economical for packaging.
Similarities:
Both are used for high-strength injection-molded parts in automotive and electronics, with smooth finishes and colorability.
Differences:
ABS offers better impact resistance and is suited for decorative parts, while polyacetal provides lower friction and higher wear resistance.
Polyacetal Advantage:
Low friction and dimensional stability for moving parts like gears and rails.
Limitation:
Higher cost and sensitivity to acids compared to ABS, which is more resistant to impact and chemicals.
Similarities:
Both are used to improve plastic properties and reduce friction in components.
Differences:
Slip masterbatch is added to polymers to reduce friction, while polyacetal has inherent low-friction properties without additives.
Polyacetal Advantage:
Inherent low friction and high strength without external additives.
Limitation:
Higher cost compared to commodity polymers enhanced with slip masterbatch.
Similarities:
Both are combined with polymers to enhance properties or appearance.
Differences:
White and colored masterbatches are designed for coloration, while polyacetal focuses on engineering properties like strength and low friction.
Polyacetal Advantage:
Superior engineering properties for technical applications without needing coloration.
Limitation:
No direct impact on color, where colored masterbatches are more suitable.
Similarities:
Both are used to improve plastic properties and reduce production costs.
Differences:
Calcium carbonate masterbatch reduces costs and adds filler strength, while polyacetal is designed for high-performance, precise components.
Polyacetal Advantage:
Superior engineering properties like low friction and dimensional stability for specialized applications.
Limitation:
Higher cost compared to commodity polymers reinforced with calcium carbonate masterbatch.
Polyacetal (POM) is an engineering polymer with high strength, low friction, and dimensional stability, used for precision components like gears and bearings.
Automotive, electronics, industrial equipment, household appliances, and consumer products.
Polyacetal has higher mechanical strength and lower friction but is more expensive. Polypropylene is more flexible and cost-effective.
Yes, specific FDA-compliant grades are safe for medical use. Verify supplier certifications.
Processed via injection molding or extrusion at 180°C to 220°C. Drying (80°C for 2-3 hours) is essential.
High strength, low friction, dimensional stability, chemical resistance, and optimal processability.
Yes, but its crystalline structure makes recycling more complex.
Homopolymer for rigidity, copolymer for chemical resistance, and reinforced grades for high strength.
Without UV stabilizers, it has limited UV resistance. UV-resistant grades are suitable for outdoor use.
Up to two years under proper conditions.
Suitable up to 100°C. For higher temperatures, specialized grades or other polymers are recommended.
Test tensile strength, MFI, moisture content, and additive dispersion. Review supplier technical reports.
It reduces maintenance costs by minimizing lubrication needs and extending part life, but initial costs are higher.
Homopolymer offers higher rigidity, while copolymer provides better chemical and thermal stability.
No, with proper processing, it does not. Adequate ventilation is recommended.
Maintain processing temperatures below 220°C and ensure strong ventilation.
Yes, its low friction and high wear resistance make it ideal for gears and bearings.