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Polypropylene Wax for Extrusion Blow Molding: Advantages and Considerations

by:Sainuo     2023-11-20

Polypropylene Wax for Extrusion Blow Molding: Advantages and Considerations


Extrusion blow molding is a widely used manufacturing process for producing hollow plastic products. To achieve optimal results, various additives are incorporated into the production process. One such additive is polypropylene wax, which provides several advantages in extrusion blow molding. This article discusses the advantages and considerations of using polypropylene wax as an additive in the extrusion blow molding process.

Advantages of Polypropylene Wax in Extrusion Blow Molding:

1. Enhanced Melt Flow:

Polypropylene wax improves the melt flow properties of the polymer used in extrusion blow molding. The addition of polypropylene wax reduces the melt viscosity, allowing for easier flow of the molten polymer during the extrusion process. This enhanced melt flow results in uniform wall thickness and improved surface finish of the blow-molded products.

2. Reduced Die Swell:

Die swell is a common issue in extrusion blow molding, which refers to the expansion of the plastic melt once it is extruded from the die. Polypropylene wax helps in minimizing die swell by reducing the friction between the polymer chains. By incorporating polypropylene wax, the dimensional stability of the blow-molded products is improved, resulting in accurate and consistent part dimensions.

3. Improved Mold Release:

Polypropylene wax acts as a lubricant, aiding in the release of the blow-molded product from the mold cavity. It reduces the coefficient of friction between the polymer and the mold surface, making it easier to remove the product without any distortion or damage. This improved mold release allows for faster cycle times and increased production efficiency.

4. Enhanced Impact Strength:

The addition of polypropylene wax in extrusion blow molding improves the impact strength of the final product. The wax acts as a toughening agent, increasing the resistance of the polymer to impact loads. This is particularly beneficial for blow-molded products that are prone to rough handling or need to withstand rigorous usage conditions, ensuring their longevity and durability.

5. Cost-Effectiveness:

Polypropylene wax is a cost-effective additive for extrusion blow molding. Due to its low melting point and compatibility with other polymers, a small amount of polypropylene wax can impart significant improvements in the processing and performance properties of the blow-molded products. This cost-effective nature makes it an attractive choice for manufacturers, enabling them to produce high-quality products at a reduced cost.

Considerations when using Polypropylene Wax in Extrusion Blow Molding:

1. Optimum Concentration:

The concentration of polypropylene wax in the polymer matrix should be carefully optimized to achieve the desired results. Too little wax may not provide the intended benefits, while excessive wax can lead to processing issues and compromise the mechanical properties of the final product. Conducting trials and adjusting the wax content accordingly is crucial to obtain the best performance.

2. Interference with Printing:

Polypropylene wax may interfere with subsequent printing processes, especially if specific ink adhesion is required. The selection of inks and printing methods should be considered in conjunction with the presence of polypropylene wax to ensure compatibility and adherence of the printing on the blow-molded products.

3. Processing Temperature:

The processing temperature plays a vital role in the successful incorporation of polypropylene wax in extrusion blow molding. The melting point of the wax should be compatible with the processing temperature used for the polymer. Failure to maintain the appropriate processing temperature can lead to poor dispersion of the wax or inadequate melt flow, limiting the effectiveness of the additive.

4. Material Compatibility:

Polypropylene wax is most commonly used with polyolefins, including polyethylene and polypropylene. However, it may not be compatible with all types of polymers. It is essential to ensure that the polypropylene wax chosen is compatible with the base polymer used in extrusion blow molding. Compatibility tests should be conducted to verify the suitability of the wax for the specific polymer system.

5. Shelf Life:

Polypropylene wax may have a limited shelf life due to the possibility of degradation or contamination over time. It is recommended to store polypropylene wax in a cool, dry place, away from sunlight and moisture, to preserve its properties. Regular testing of the wax's performance and quality is advised to ensure consistency and effectiveness in extrusion blow molding processes.


Polypropylene wax offers numerous advantages in extrusion blow molding, enhancing melt flow, reducing die swell, improving mold release, and increasing impact strength. Additionally, it provides cost-effectiveness, making it a preferred additive for manufacturers. However, considerations such as optimal concentration, interference with printing, processing temperature, material compatibility, and shelf life must be taken into account when incorporating polypropylene wax in extrusion blow molding processes. By carefully assessing these factors, manufacturers can leverage the benefits of polypropylene wax to produce high-quality blow-molded products efficiently.

Qingdao Sainuo Chemical Co.,LTD. is a gaint manufacturer of pe wax, which is one of the most outstanding product produced from us.
Deliver value to our customers by providing the most reliable and efficient products as pe wax.
Qingdao Sainuo Chemical Co.,LTD. can assure you that we never compromise on our quality standards and are one of the best in the market at present.
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