POM Plastic Granules Polyoxymethylene Material

According to the different chemical structures in its molecular chain, it can be divided into homo polyoxymethylene and copolymerized polyoxymethylene. The important differences between the two are: the density, crystallinity, and melting point of homo polyoxymethylene are high, but the thermal stability is poor, the processing temperature range is narrow (about 10 ° C), and the stability to acid and alkali is slightly lower; while the density, crystallinity and melting point of polyformaldehyde copolymer The melting point and strength are low, but the heat stability is good, it is not easy to decompose, the processing temperature range is wide (about 50 ℃), and the acid and alkali stability is good. It is an engineering plastic with excellent comprehensive properties. It has good physical, mechanical, and chemical properties, especially excellent friction resistance. Commonly known as Saigang or Duangang, it is the third largest general-purpose engineering plastic. It is suitable for making anti-friction and wear-resistant parts, transmission parts, chemical industry, instruments,s and other parts.

One of the synthetic resins, also known as polyoxymethylene resin, POM plastic, Saigang material, etc.; is a white or black plastic particle with high hardness, high rigidity, and high wear resistance. Mainly used for gears, bearings, auto parts, machine tools, instrument internals, and other products that play a skeleton role.

Scope of Application

It is suitable for making anti-friction and wear-resistant parts, transmission parts, chemical industry, instrument and other parts. Rigid, high wear-resistant characteristics. Mainly used for gears, bearings, auto parts, machine tools, instrument internals and other products that play a skeleton role.

POM Plastic Granules

Features of POM Plastic Granules

(1) POM material does not need to be dried before processing, it is better to preheat (about 80°C) during processing, which is good for the stability of product size;

(2) The processing temperature of POM is very narrow (0~215°C), and it will decompose when it stays in the barrel for a long time or when the temperature exceeds 220°C, producing irritating formaldehyde gas;

(3) When POM material is injected, the holding pressure should be higher (similar to the injection pressure) to reduce the pressure drop. The screw speed should not be too high, and the residual amount should be small;

(4) The shrinkage rate of POM products is large, and it is easy to shrink or deform. POM has a large specific heat, and high mold temperature (80~100°C), and the product is very hot when demoulded, so it is necessary to prevent burns to fingers;

(5) POM should be molded and processed under the conditions of "medium pressure, medium speed, low material temperature, and high mold temperature". When precision products are molded, it is necessary to control the mold temperature

(6) High mechanical strength and rigidity;

(7) Highest fatigue strength;

(8) Good environmental resistance and organic solvent resistance;

(9) Strong resistance to repeated impact, good electrical properties, good recovery, self-lubrication, good wear resistance, and excellent dimensional stability.

Application of POM Plastic Granules

It can replace most non-ferrous metals, automobiles, machine tools, instrument internals, bearings, fasteners, gears, springs, pipes, conveyor belt accessories, electric kettles, pump casings, drainers, faucets, etc.

POM Plastic Granules Shipment

Physical and Chemical 

General Performance of POM Plastic Granules

Polyoxymethylene is a hard and dense material with a smooth and shiny surface, light yellow or white, and the thin-walled part is translucent. The combustion characteristics are easy to burn and continue to burn after leaving the fire. The upper end of the flame is yellow, and the lower end is blue. Melting and dripping occur, and there is a strong irritating smell of formaldehyde and a fishy smell. POM is a white powder, generally opaque, with good colorability, specific gravity 1.41-1.43 g/cm3, molding shrinkage rate of 1.2-3.0%, molding temperature 170-200°C, drying condition 80-90°C for 2 hours. The long-term heat resistance of POM is not high, but it can reach 160°C in the short term. The short-term heat resistance of homopolymerized POM is more than 10°C higher than that of copolymerized POM, but the long-term heat resistance of copolymerized POM is about 10°C higher than that of homopolymerized POM. It can be used for a long time in the temperature range of -40℃~100℃. POM is easy to decompose, and the decomposition temperature is 240 degrees. Irritant and corrosive gases are produced during decomposition, so the mold steel should be made of corrosion-resistant materials.

(1) POM is a crystalline plastic with a density of 1.42g/cm3, and its rigidity is very good, commonly known as "Sayang".

(2) It has excellent properties such as fatigue resistance, creep resistance, wear resistance, heat resistance, impact resistance, etc., and has a small friction coefficient and good self-lubrication.

(3) POM is not easy to absorb moisture, and its water absorption rate is 0.22~0.25%. It has good dimensional stability in a humid environment, and its shrinkage rate is 2.1% (larger). It is difficult to control the size during injection molding, and its thermal deformation temperature is 172°C. POM has two kinds of homo polyoxymethylene, with different properties (homo polyoxymethylene has better temperature resistance).

Mechanical Properties of POM Material

POM has high strength and rigidity, good elasticity, good wear resistance, and wear resistance. Its mechanical properties are excellent, the specific strength can reach 50.5MPa, and the specific stiffness can reach 2650MPa, which is very close to the metal. The mechanical properties of POM change slightly with temperature, and the change of copolymerized POM is slightly larger than that of homopolymerized POM material. The impact strength of POM is higher, but the conventional impact is not as good as ABS and PC; POM is sensitive to the gap, and the impact strength can be reduced by as much as 90% if there is a gap. The fatigue strength of POM is very prominent. After 10 alternating loads, the fatigue strength can reach 35MPa, while PA and PC are only 28MPa. The creep property of POM is similar to that of PA, it is only 2.3% at 20°C, 21MPa, and 3000h, and it is little affected by temperature. The friction coefficient of POM is small, the wear resistance is good (POM>PA66>PA6>ABS>HPVC>PS>PC), the limit PV value is very large, and the self-lubricating property is good. When POM products are rubbed against each other, it is easy to produce squealing noise under high load.

Electrical Properties of POM Material

POM has good electrical insulation and is hardly affected by temperature and humidity; the dielectric constant and dielectric loss change little in a wide range of temperature, humidity, and frequency; it has excellent arc resistance and can be used at high temperatures. Keep. The dielectric strength of POM is related to the thickness. When the thickness is 0.127mm, it is 82.7kV/mm, and when the thickness is 1.88mm, it is 23.6kV/mm.

Environmental performance

POM is not resistant to strong alkalis and oxidants and has certain stability to alkenoic acids and weak acids. POM has good solvent resistance, can resist hydrocarbons, alcohols, aldehydes, ethers, gasoline, lubricating oil, weak alkali, etc., and can maintain considerable chemical stability at high temperatures. Low water absorption and good dimensional stability.

The weather resistance of POM is not good. Under the action of ultraviolet rays for a long time, the mechanical properties will decrease, and the surface will be pulverized and cracked.

Fold formability

Crystalline material has a narrow melting range, fast melting, and solidification, and crystallization occurs when the material temperature is slightly lower than the melting temperature. Medium mobility. Hygroscopicity is small, without drying treatment.

Modified POM of POM Material

1. Enhanced POM

The main reinforcing material is glass fiber, glass sphere or carbon fiber, etc., and glass fiber is the most commonly used. After reinforcement, the mechanical properties can be increased by 2 to 3 times, and the heat distortion temperature can be increased by more than 50 °C.

2. High lubrication POM

Adding graphite, F4, molybdenum disulfide, lubricating oil, and low molecular weight PE to POM material can improve its lubricating performance. For example, adding 5 parts of F4 to POM can reduce the friction coefficient by 60% and increase the wear resistance by 1~2 times. For another example, adding liquid lubricating oil to POM can greatly improve wear resistance and limit PV value. In order to improve the dispersion effect of oil, it is necessary to add oil-absorbing carriers such as carbon black, aluminum hydroxide barium sulfate, and ethylene-propylene rubber. Adding 5% oil, the friction of POM material increases by 72%, and the limit PV value can reach 3.9MPa m/s (pure POM is 0.213MPa m/s), which is 3~20 times that of other engineering plastics.