Polyethylene Wax (PE Wax) and Its Modified Products (e.g., Oxidized Polyethylene Wax, OPE)
These materials are widely used across multiple industries due to their unique physicochemical properties:
- Low viscosity
- High melting point
- Exceptional lubricity and dispersibility
I. Plastics Processing (Core Application)
1. PVC Products
- Rigid PVC (window profiles, pipes, sheets):
- External lubricant: Reduces melt friction with equipment (screw, mold), prevents adhesion, enhances surface gloss.
- Release agent: Minimizes die buildup, extends mold cleaning cycles.
- Flexible PVC (wires/cables, films, artificial leather):
- Anti-blocking agent: Prevents interlayer adhesion (e.g., 0.2–0.5 phr).
- Dispersant: Promotes uniform dispersion of fillers (e.g., CaCO₃, TiO₂).
2. Polyolefin Products (PP/PE films, injection moldings, fibers):
- Lubricant: Improves melt flow, reduces screw torque (e.g., 0.1–0.3 phr in injection molding).
- Anti-blocking agent: Replaces silica in packaging films—cost-effective and dust-free (e.g., 0.1–0.2% in LDPE films).
3. Engineering Plastics & Alloys (ABS, PC, PA):
- Flow modifier: Enhances melt stability during high-temp processing (e.g., 0.3% in flame-retardant ABS).
- Pigment dispersant: Prevents agglomeration in color masterbatches (see Section II).
II. Masterbatches & Functional Additives (Key Roles)
1. Universal Color Masterbatches (PP/PE-based):
- Carrier resin: Low-MW carrier for high pigment loading (30–70% content).
- Dispersant: Encapsulates pigments under shear, improves color strength, eliminates "speckles" (e.g., 10–15% in carbon black masterbatch).
2. High-Load Masterbatches (e.g., flame retardant, anti-static):
- Co-dispersant: Synergizes with stearates to prevent agglomeration of functional additives (e.g., Mg(OH)₂).
III. Rubber Industry
1. Tires & Rubber Products:
- Internal lubricant: Reduces compound viscosity during internal mixing, shortens mixing time (replaces partial process oil).
- Physical anti-ozonant: Migrates to surface, forms protective wax film against ozone (e.g., 1–2 phr in SBR).
- Release agent: Prevents sticking of semi-finished products (common in open-mill mixing).
2. Specialty Rubbers:
- Silicone rubber: Improves extrusion surface smoothness (requires low-MW PE wax).
IV. Coatings & Inks
1. Powder Coatings:
- Matting agent: Creates micro-roughness via crystalline structure for satin finish (e.g., 0.5–1.5% in epoxy coatings).
- Flow control agent: Enhances leveling, reduces orange peel.
2. Solvent-Based Inks:
- Abrasion resistance aid: Improves scratch resistance (e.g., 3–5% in gravure inks).
- Matting agent aligner: Orients matting particles for uniform satin effect.
V. Emerging Applications
1. Hot-Melt Adhesives (HMA):
- Viscosity modifier: Lowers application temperature for EVA-based HMAs (5–10% addition).
- Anti-blocking agent: Prevents self-adhesion of adhesive films.
2. Wood-Plastic Composites (WPC):
- Interfacial compatibilizer: Enhances wood-plastic (PE/PP) bonding, reduces water absorption.
3. 3D Printing Filaments:
- Processing aid: Improves extrusion fluidity of PLA/ABS filaments, prevents nozzle clogging.
VI. Selection Guidelines
Parameter | Recommended Applications | Typical Examples |
Low MW | Rubber open-milling, flexible PVC | PE wax (Mₙ=1,000–3,000) |
Medium-High MW | Masterbatches, engineering plastics | PE wax (Mₙ=3,000–8,000) |
Oxidized Type | PVC internal mixing, polar systems (PA/PC) | OPE wax (Acid value: 15–20 mgKOH/g |
Narrow MW Distribution | Premium film anti-blocking, medical packaging | Fischer-Tropsch wax (Melt range ≤5°C)
|
VII. Restricted Applications
- Transparent PC/PMMA parts: May cause haze.
- Food-contact plastics: Requires FDA-compliant grades (e.g., Clariant Licocene® PE).
- Ultra-high-temp plastics (PEEK >350°C): Risk of thermal degradation.
Summary:
PE wax acts as an "industrial staple" in polymer processing, delivering core functionalities:
Lubrication (viscosity reduction, mold release)
Dispersion (pigments/fillers)
Surface modification (anti-blocking, matting, wear resistance)
Precise selection by MW, oxidation degree, and melting point significantly enhances performance and cost efficiency.
