The performance of POM, what material does POM enhance with POM to increase viscosity

Polyacetal (POM).

Properties It is a crystalline thermoplastic plastic, with an obvious melting point of 165 175, and its properties are closest to metal, and it is generally called plastic steel.

Advantage 1, high mechanical strength and rigidity.

2. Highest fatigue strength.

3. Good environmental resistance and organic solvent resistance.

4. Strong resistance to repeated impacts.

5. Wide operating temperature range (-40 120) 6. Good electrical properties.

7. Good resilience.

8. It has its own lubrication and good wear resistance.

9. Excellent size stability.

Disadvantages: 1. If the processing process is high temperature for a long time, it is easy to decompose.

2. No self-extinguishing.

3. Poor acid resistance.

4. Large forming shrinkage.

Uses Electronic appliances: washing machines, juicer parts, timer components.

Automotive: handlebar parts, power window parts.

Industrial parts: mechanical parts, gears, handles, toys, screws.

Polyoxymethylene (POM), also known as polyoxymethylene. Around 1955, DuPont polymerized formaldehyde to obtain formaldehyde homopolymers. POM is a milky opaque highly crystalline linear polymer that is a self-lubricating material and belongs to one of the five major engineering plastics.

Density, melting point 175, decomposition temperature 235 240, excellent dyeing performance, strength, stiffness, impact strength, creep resistance, fatigue resistance, dimensional stability, small moisture absorption; It can be used in 85 water for a long time, chemical resistance, oil resistance, wide range of operating temperatures, and can be used for a long time between -40 100, which is an engineering plastic with excellent performance and ideal replacement for non-ferrous metals such as copper and tin. Q group 137218701

Summary. High viscosity POM - POM can be further improved through various enhancement modifications, such as glass fiber reinforcement can increase the rigidity and strength of the material itself, can also be improved by other alloys including TPU, PVC and other alloys or additives to improve toughness and impact strength, can also be improved through mineral filling to improve the surface appearance and flatness of the product, etc., by adding Teflon or molybdenum disulfide to further improve scratchability, etc., but POM can not be modified to achieve the level of flame retardant. Because POM is easy to decompose in the thermoforming process, for example, the decomposition of flame retardant in the thermoforming process will add a large amount of decomposition of POM, and because this material is divided into 5 structures, it is also difficult to be compatible with accelerants, so the development of flame retardant POM in the future is quite difficult.

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High viscosity POM - POM can be modified through a variety of enhancements to further improve the scope of application, such as through glass fiber reinforcement can increase the rigidity and strength of the material itself, can also be improved by other alloys or additives including TPU, PVC and other alloys or additives, can also be used to improve the surface appearance and flatness of the product slag book through mineral filling, etc., by adding Teflon or molybdenum disulfide to further improve scratchability, etc., but POM can not be modified to achieve the level of flame retardant. Because POM is easy to decompose in the thermoforming process, for example, the decomposition of flame retardant in the thermoforming process will add a large amount of decomposition of POM, and because this material is divided into 5 structures, it is also difficult to be compatible with the accelerant, so the development of flame retardant POM in the future is quite difficult.

Polyoxymethylene plastics do have higher formaldehyde content than other engineering plastics.

Polyoxymethylene POM is an engineering plastic formed by the polymerization of formaldehyde, formaldehyde is a chemical product, and is a monomer material for polymerizing POM. Polyoxymethylene plastic (granular), formaldehyde is liquid.

Therefore, theoretically speaking, polyoxymethylene plastic does not contain formaldehyde.

Other engineering plastics, such as PA, PC, PBT, PPO, etc., are not made of formaldehyde, and formaldehyde is not present in the polymerization process. Therefore, other engineering plastics do not have formaldehyde content.

However, in fact, it is impossible to do 100% polymerization of polyoxymethylene in the polymerization production, and there is still a certain amount of monomer formaldehyde, and there will be a certain amount of formaldehyde released in the storage of polyoxymethylene plastic and the later injection molding production process. Therefore, polyoxymethylene is indeed higher than other engineering plastics.

To reduce the formaldehyde content of acetal plastic or its products, first of all, we must choose high-quality polyoxymethylene materials, the lower the odor, the better, the smell is large, which means that the formaldehyde content is high. After injection molding, it is recommended to store the POM product in an open place for a period of time to reduce the odor before packaging.

It is a polymer of formaldehyde, which is composed entirely of formaldehyde.

Sorting out the problems and solutions of polyoxymethylene (POM) products.

01 Q: POM parts have poor aging resistance, and the products are easy to turn yellow.

This is mainly due to the poor thermal stability of the resin itself, which is easy to be oxidized during use, and the large molecules break to form small molecules or generate some chromogenic groups, resulting in yellowing; The anti-aging system and heat stabilizers can be improved, such as adding more antioxidants and light stabilizers to delay aging and prolong the service life.

02 Q: The flame retardancy of the polyoxymethylene cable sheath is poor.

The flame retardancy of POM itself is relatively poor (flammable compared to general synthetic polymer materials), and the thermal stability is poor, so it is difficult for POM flame retardant to achieve V0, and its flame retardancy can usually be improved by adding flame retardants, but due to the molecular structure characteristics of POM, conventional halogen-containing flame retardant systems such as halophosphate esters, halogen paraffins, and antimony trioxide will not only not improve the flame retardancy of the material when added to POM, but will aggravate the combustion of polyoxymethylene.

It is recommended to add intumescent flame retardants, such as red phosphorus, phosphate, aluminum hydroxide (magnesium), tricyanuric acid and polymelamine salt, etc., or several of them can be used in combination.

03 Q: What can be added to recycled polyoxymethylene to increase toughness and luster?

Due to the high crystallinity of POM, the large crystalline grains, the low notched impact strength, and the tendency to fracture in a brittle manner, there are two main ways to improve the impact toughness of POM:

1) Toughening of elastomers (commonly used elastomers such as TPU, EPDM, nitrile rubber, silicone rubber, etc.);

2) Toughening of rigid particles (commonly used are talc, diatomaceous earth, titanium dioxide, calcium carbonate, glass beads, etc.), POM material itself has the characteristics of smooth surface and shiny, so it can also be improved by processing aids, such as adding an appropriate amount of release agent, internal lubricant, etc.

04 Q: Which type of polyoxymethylene toughened TPU to choose? What compatibilizers are used?

1) Different types of TPU were used to toughen and modify polyoxymethylene, and the results showed that polycaprolactone copolyester TPU had a better toughening effect.

2) The amount of TPU has a great impact on the performance of the toughened material, when the amount of TPU is 40%, due to the formation of a double continuous phase structure of the blend, the impact performance is abrupt, and the toughening effect is the best.

3) It can also be used as a compatibilizer by adding SEBS-G-MA.

05Q: How to solve the problem of large shrinkage of POM?

The basic attribute of POM itself is that the shrinkage rate is relatively large, which can usually be enhanced by adding fillers such as glass fiber, and at the same time, the shrinkage degree can be significantly reduced.

The scientific name of polyoxymethylene polyoxymethylene (POM) is also known as saigang and special steel. It is obtained by polymerization of formaldehyde and other raw materials.

POM-H (polyoxymethylene homopolymer) and POM-C (polyoxymethylene copolymer) are high-density, high-crystallinity thermoplastic engineering plastics.

It has good physical, mechanical and chemical properties, especially excellent friction resistance.

AnswerPOM, also known as polyoxymethylene, is a non-toxic, hard, dense material with a smooth and shiny surface, which is used in automotive parts, instrumentation, machine tools, etc. POM has high strength and stiffness, and its mechanical properties are very similar to those of metallic materials.

POM is a hard and dense material with a smooth surface and a glossy color. It is light yellow or white and can be used for a long time in temperatures ranging from -40 to 100°C. Its abrasion resistance and self-lubricating properties are better than most engineering plastics, and it has good oil and peroxide resistance.

Professional high-temperature resistant POM, toughened POM, reinforced POM, weather-resistant POM, extrusion POM, wear-resistant POM, self-lubricating POM, antistatic POM, etc.

Seek solutions from three aspects: raw materials, molds, and injection molding processes.

Raw materials: Warpage-resistant models.

In terms of molds: 1) The thickness and quality of the parts should be uniform.

2) The design of the cooling system should make the temperature of all parts of the mold cavity uniform, and the gating system should make the material flow symmetrical to avoid warping caused by different flow directions and shrinkage rates, appropriately thicken the sub-runners and sprue of the parts that are difficult to form, and try to eliminate the density difference, pressure difference and temperature difference in the cavity.

3) The transition area and corner of the thickness of the workpiece should be smooth enough, and there should be good demoulding, such as increasing the demoulding margin, improving the polishing of the die surface, and maintaining the balance of the ejection system.

4) The exhaust should be good.

5) Increase the wall thickness of the part or increase the anti-warpage direction, and enhance the anti-warpage ability of the part by the stiffener.

6) The strength of the material used in the mold is insufficient.

Processing: 1) The pressure is too high, the holding time is too long, and the melting temperature is too low and the speed is too fast, which will cause the internal stress to increase and warp deformation.

2) The mold temperature is too high and the cooling time is too short, so that the workpiece during demoulding is overheated and the ejection deformation occurs.

3) Reduce the screw speed and back pressure while maintaining a minimum charge to limit the generation of internal stress.

4) If necessary, the parts that are easy to warp and deform can be softly shaped or annealed after demolding.

1. It has a very low coefficient of friction and good geometric stability, especially suitable for making gears and bearings 2. It has the characteristics of high temperature resistance, and is also used for pipeline devices (pipeline valves, pump housings), lawn equipment, etc. 3. It is a tough and elastic material, which has good creep resistance, geometric stability and impact resistance even at low temperature. 4. The homopolymer material has good ductility strength and fatigue resistance, but it is not easy to process.

Copolymer materials are thermally and chemically stable and easy to process. Both homopolymer and copolymer materials are crystalline and do not easily absorb water. 5. The high crystallization range mold index slag degree leads to its quite high shrinkage, which can reach 2% high.

There are different shrinkage rates for a variety of different reinforcement materials. 6. It has good comprehensive properties, it is the hardest in thermoplastics, and it is one of the varieties with mechanical properties closest to metal in plastic materials, and its tensile strength, bending strength, fatigue strength, wear resistance and electrical properties are very good, and can be used for a long time between -40 and --100. 7. It is a crystalline plastic, the melting point is obvious, once the melting point is reached, the melt viscosity decreases rapidly.

When the temperature exceeds a certain limit or the melt is heated for too long, it will cause decomposition. Copper is a catalyst for POM degradation, and copper or copper materials should be avoided in areas that come into contact with POM melts. 8. According to the different molecular chain structures, polyoxymethylene can be divided into homopolymeric formaldehyde and copolymer formaldehyde.

The density, crystallinity and melting point of the former are high, but the thermal stability is poor, the processing temperature range is narrow (10), and the stability of acid and alkali is slightly lower; The latter has low density, crystallinity and melting point, but has good thermal stability, is not easy to decompose, and has a wide processing temperature range (50). The disadvantages of polyoxymethylene are: corrosion by strong acid, poor weather resistance, poor adhesion, thermal decomposition and softening temperature are close, and the oxygen limiting index is small.