What Does “High Density” Mean in Oxidized Polyethylene Wax?

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2026-02-17

In the specification sheets for Oxidized Polyethylene (OPE) Wax, “density” is often just a number—typically ranging from 0.96 to 0.99 g/cm³. However, for formulators in coatings, inks, and PVC processing, this number tells a crucial story about molecular structure and performance potential.

Understanding the difference between High Density (HDOPE) and Low Density (LDOPE) waxes allows technical teams to predict wear resistance, thermal stability, and emulsification behavior before a trial even begins.

What Does “High Density” Actually Mean?

Density reflects how closely polymer chains pack together:

Lower-density PE structures: more chain branching → lower crystallinity → softer feel
Higher-density PE structures: more linear chains → higher crystallinity → higher hardness

Important: Density is not the same as oxidation level. The “oxidized” part relates to the introduction of polar groups (often reflected by parameters such as acid value), which can improve wetting/adhesion in certain systems.

Key Performance Advantages of High Density

1. Superior Wear and Scratch Resistance

In coatings and printing inks, hardness is directly linked to density. HDOPE waxes form substantially harder particles than LDOPE or standard paraffin. When these particles migrate to the surface (or are dispersed within the film), they act as “spacers” or slip agents that deflect physical stress.

Result: Better scratch resistance in wood coatings, coil coatings, and floor finishes.

2. Higher Thermal Stability (Melting Point)

HDOPE waxes typically soften and melt at higher temperatures (often >130°C, depending on grade) compared to low-density variants.

Benefit: In plastics processing (like rigid PVC extrusion), the wax remains solid/viscous longer in the extruder barrel, providing “delayed” external lubrication or metal release in later zones without degrading too early.

3. Improved Mechanical Strength

Because the polymer chains are linear and tightly packed, the wax itself is less brittle than low-molecular-weight by-products but harder than LDPE waxes.

Impact: In hot melt adhesives (HMA) or plastic composites, it modifies viscosity without sacrificing the structural integrity or softening point of the final product as much as softer waxes might.

Typical Applications

Choosing the Right High-Density Oxidized Polyethylene Wax

Rallychem offers a comprehensive range of high-density oxidized polyethylene wax grades with carefully controlled density, melting points, molecular weights, and oxidation levels. These parameters can be adjusted to optimize wear resistance, hardness, thermal stability, slip, and scratch resistance across different application systems, including plastics, coatings, and printing inks.

By balancing polarity and molecular structure, our high-density oxidized polyethylene wax solutions ensure excellent dispersion and stable surface performance without compromising processing efficiency. Our technical experts work closely with customers to customize solutions that meet exact production conditions and performance requirements.

結論

“High Density” in Oxidized Polyethylene Wax translates directly to physical durability and thermal resilience. By selecting a high-density grade, manufacturers can improve scratch resistance in coatings and stability in PVC extrusion, achieving high performance even at low dosages.

Rallychem offers a specialized series of HDOPE waxes with controlled density and oxidation levels. Whether you need a high-acid number for emulsions or a high-hardness grade for coatings, we can help match the spec to your application.