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What is the use of polyethylene / pe wax in plastics?

What is the use of polyethylene / pe wax in plastics?

2021-10-18

Polyethylene wax, also known as low molecular weight polyethylene and polymer wax, is abbreviated as PE wax. In recent years, the production scale and application field of pe wax in China have developed rapidly. It has become a lubricant, brightener and dispersant in plastics, rubber, leather, paint, pigment, hot melt adhesive, candles, low-voltage electrical appliances, cosmetics and so on. This paper briefly introduces the application of polyethylene wax in PVC, modified masterbatch, color masterbatch and engineering plastics for reference.

1. Application of pe wax in PVC products

PVC resin is unstable to heat during processing and molding, so it is necessary to add heat stabilizer or molding lubricant during molding. The lubricant can prevent the resin from staying in the plastic product processing machinery or causing resin decomposition due to local overheating, and make the resin easy to form. Generally, there are three types of lubricants: internal lubricants characterized by reducing the friction between PVC molecules and improving the internal fluidity; An external lubricant that prevents resin from adhering to the inner wall of the processing molding machine and an internal and external lubricant with both the above two functions. 

The compatibility between lubricant and resin depends on the molecular structure of lubricant, such as carbon chain length, molecular polarity and so on.

Polyethylene wax can be used as an external lubricant for PVC because of its long carbon chain and no polar group. If polyethylene wax of high density and medium density is used as a lubricant for calendering, extrusion, injection molding and molding, the following effects will be produced:

(1)Excellent external lubrication

During calendering forming, it has the effect of preventing adhesion to rolls; During extrusion molding, injection molding and molding, it can effectively prevent adhesion of screws and molds, improve demoulding effect and improve the beauty of plastic products.

(2) It also has the effect of internal lubrication

In particular, chlorinated polyethylene wax can also play the effect of internal lubrication because of its polar groups in its molecules.

(3) The addition amount is small and the lubrication effect is obvious

Generally adding 0.5% polyethylene wax can achieve very good lubrication effect, thereby increasing the extrusion volume or reducing the torque load of the main engine in the production of PVC. When adding more than 0.5% in the pure PVC, due to the excessive lubrication, the gelatinization is slow, the extrusion amount is reduced, and the effect is not good. In addition, the amount of polyethylene wax should be increased appropriately in the PVC products with inorganic powder. Inorganic powder and polyethylene wax should be increased in the same amount, and satisfactory results will be obtained.

(4) The compound effect with other additives is good

Polyethylene wax can play a good external lubrication effect when mixed with metal ester soap, lead or organotin stabilizer of PVC. External lubricants are generally combined with internal lubricants such as fatty acid alcohol esters to give play to the synergistic lubrication effect.

(5) Does not affect transparency

When the amount of polyethylene wax added to PVC is 0.3%, it does not affect the transparency of PVC, while the use of high-density polyethylene wax (molecular weight 2000-4000) or low acid value type of chlorinated polyethylene wax (acid value about 1.0, molecular weight about 4000) has the least impact on the transparency of PVC.

(6) Good thermal stability, no frost, no demoulding

The addition of polyethylene wax in PVC will not produce initial dyeing, so PVC has good thermal stability; There will be no frost on the formed crystal surface, and there will be no demoulding on the roll surface and molding surface.

(7) Good dispersion

In particular, micro powdered polyethylene wax is easier to be evenly mixed with PVC and evenly dispersed in PVC products.

(8) Non toxic

Because polyethylene wax has no toxicity, it can be used to contact products in food, medicine, daily chemicals, daily necessities and so on, without toxic and side effects on human body.

2. Application of polyethylene wax in modified masterbatch and color masterbatch

(1) Application of polyethylene wax in modified masterbatch

At present, the production and application of polyolefin filled modified masterbatch is very common. Due to market competition and product use, the masterbatch price is low and the enterprise benefit is poor. Many factories use a large number of paraffin instead of resin. After users add masterbatch, the product quality is affected. In production, paraffin and other additives are easy to decompose under the action of high temperature, high pressure and high shear, The smoke pollutes the production environment and increases the material consumption. The torque and head pressure of the main engine are significantly increased, and the product dispersion and output are also affected. This is mainly because the lubricity of additives such as paraffin decreases at high temperature, resulting in the decomposition or precipitation of low molecular materials. Therefore, we In the production of modified masterbatch such as polyethylene, 2% ~ 3% polyethylene wax is used instead of paraffin and other additives, which can effectively reduce the smoke generated in the production environment and reduce the material consumption. In particular, while increasing the output, it can effectively reduce the torque and head pressure of twin-screw extrusion granulation unit, and the host current is reduced by 10% - 20%. When applied in plastic products, the product has uniform dispersion, The appearance of the products has also been significantly improved.

(2) Application of polyethylene wax in color masterbatch processing

Polyethylene wax is widely used in color masterbatch processing. The purpose of adding polyethylene wax is not only to improve the processing performance of Color Masterbatch system, but also to promote the dispersion of pigments in color masterbatch. The quality of Color Masterbatch mainly depends on the dispersion of pigments. Pigment dispersion is very important for color masterbatch. Good pigment dispersion and high coloring power of color masterbatch, The coloring quality of the product is good and the color cost is low. Polyethylene wax can improve the pigment dispersion level to a certain extent. It is a common dispersant in the production of color masterbatch. Color masterbatch is a pigment concentrate with resin as carrier. Pigment exists in three states: primary particle, condensate and aggregate. The dispersion mechanism of raw materials is the process of breaking aggregate particles into agglomerates and primary particles, and stabilizing the newly generated particles. The dispersion process of pigment in resin can be represented by the following three steps: firstly, the resin melt moistens the surface of pigment aggregate and penetrates into the internal pores; Secondly, the aggregates are broken under the action of external shear force and impact collision between pigment particles; Finally, the newly generated pigment particles are wetted and coated by the resin melt, which is stable and no longer agglomerated. These three steps can be simply expressed as lubrication - crushing - stabilization.

The resin melt has high viscosity and poor compatibility with the pigment surface, so it has poor wetting and is difficult to penetrate into the pores of the pigment group. Therefore, it can not effectively transfer the shear force, and it is difficult to better break the pigment group and disperse evenly. Even after the pigment group is broken, the resin solution can not quickly wet and protect the new surface, In order to solve this problem, polyethylene wax can be added in the processing of color masterbatch.

When processing the color masterbatch system with polyethylene wax, the polyethylene wax is first dissolved with the resin and wrapped on the pigment surface. Due to its low viscosity and good compatibility with pigments, polyethylene wax is easy to wet pigments and penetrate into the internal pores of pigment clusters, weaken cohesion, make pigment aggregates easier to open under the action of external shear force, and the newly generated particles can also be quickly wetted and protected. In addition, polyethylene wax can reduce the viscosity of the system and improve the fluidity. Therefore, adding polyethylene wax in the production of color masterbatch can improve the production efficiency, increase the output, increase the pigment concentration and improve the application performance of color masterbatch.

Polyethylene wax can improve the processability, surface gloss, lubricity and thermal stability of HDPE, PP and PVC as a strong color masterbatch dispersant for a variety of thermoplastic resins and a lubricating dispersant for filling masterbatch and degradation masterbatch.

After adding 3% ~ 5% polyethylene wax to paraffin, the melting point of paraffin can be increased from 56-58 ℃ to 70-80 ℃, which is beneficial to improve the thermal stability of additives, coupling agents and plastic products.

3. Application of pe wax in engineering plastics

Polyethylene wax can be added to the resin as an improver to improve its melt flow rate. Adding an appropriate amount of polyethylene wax to engineering plastics can improve the melt flow rate, improve the compatibility and processing stability of composites, and improve the aging resistance and external brightening effect of products. For example, adding about 0.1% polyethylene wax to nylon can achieve a melt flow rate of 6.7g/10min, However, only 5.6g/10min without polyethylene wax. Polyethylene wax is used in household appliances, automobiles, machinery and other products produced by modified plastics such as ABS and polyurethane. It can not only improve the appearance brightness, extinction effect and wear resistance of plastic products, but also improve the compatibility and dispersion of different materials, especially the processing technology of adding ultra-fine inorganic materials and the performance of plastic products.

Polyethylene wax is used as a lubricant for cable insulation materials, which can enhance the dispersion of fillers, improve the extrusion rate, increase the mold flow and improve the demoulding effect.

Additives are called "monosodium glutamate" in the plastic industry " , polyethylene wax is a useful modified functional additive in the processing technology of plastic products. Not only its lubricating performance and thermal stability have been recognized by the industry, but also polyethylene wax can improve the aging resistance of plastic products, the appearance light malaria effect, reduce the plasticizing viscosity, reduce the extrusion pressure of equipment, improve the operating torque of processing equipment, save energy and reduce consumption, which is conducive to the dispersion effect of products and reduce material consumption Decomposition caused by excessive heating, pressure and shear. 

Because the melt viscosity of polyethylene wax is greater than that of paraffin wax, adding an appropriate amount of polyethylene wax is conducive to the dispersion of products. When the concentration of polyethylene wax exceeds a certain value, the dispersion effect will decline. The optimal dosage of polyethylene wax with different molecular weight in different products is also different, which needs to be combined with processing equipment, process conditions The best formula and dosage are found through repeated experiments, so as to achieve the lowest production cost and obtain the best quality and benefit. The excellent properties of polyethylene wax provide good physical and chemical properties for the development of new products. The research, test, application and promotion of polyethylene wax broaden the field of plastic processing and application, improve the performance and reduce the material consumption. It will become a new kind of functional material and provide a broader development prospect for the development of plastic industry.

Qingdao Sainuo Chemical Co., Ltd. We are manufacturer of  PE wax, PP wax, OPE wax, EVA wax, PEMA, EBS, Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing.

Sainuo rest assured wax, welcome your inquiry!

Website:https://www.sainuowax.com

E-mail:sales@qdsainuo.com

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Address:Room 2702,Block B, Suning Building, Jingkou Road, Licang District, Qingdao,China


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