Chlorinated Paraffin Wax: Properties, Classification, and Industrial Uses
Definition
Chlorinated paraffin (CP) is a chlorinated derivative of paraffin hydrocarbons, characterized by low volatility, flame retardancy, excellent electrical insulation, and cost-effectiveness. Its general molecular formula is
,where n = 10–30 (carbon chain length) and m = number of chlorine atoms.
Physical Properties
· Appearance:
- Short-chain CPs: Colorless or pale yellow viscous liquids.
- Long-chain CPs: Solid forms.
· Density: Increases with chlorine content (typically 1.16–1.7 g/cm³).
- Liquid CPs (40–50% chlorine): Lower density (~1.16–1.26 g/cm³).
- Solid CPs (≥70% chlorine): Higher density (~1.65 g/cm³).
· Solubility:
- Insoluble in water, but soluble in organic solvents (benzene, ether, ketones).
- Higher chlorination may alter solubility in non-polar solvents.
Chemical Properties
· Stability:
- Relatively stable but decomposes under high heat/UV light, releasing hydrogen chloride (HCl).
· Reactivity:
- Can corrode metals, especially in the presence of moisture.
Classification of Chlorinated Paraffin
1. By Chlorine Content
2. By Carbon Chain Length
Industrial Applications
1. Plastics Industry (Primary Application Sector)
As one of the most cost-effective secondary plasticizers, chlorinated paraffin plays a crucial role in the plastics sector:
PVC Applications:
· Flexible PVC Products: Used in cable insulation (replacing 30-50% of primary plasticizers like DOP)
· Rigid PVC Formulations: Acts as processing aid and flame retardant (3-5% addition)
· Flooring Materials: Provides dimensional stability and reduces fogging (8-12% typical loading)
· Automotive Parts: Dashboard components and underbody coatings benefit from its low-temperature properties
Technical Advantages:
· Reduces formulation costs by 15-30% compared to phthalate plasticizers
· Low volatility ensures long-term performance (evaporation loss <0.5% at 90°C)
· Synergistic effect with antimony trioxide (flame retardancy improvement up to 30%)
2. Rubber Industry (Critical Performance Modifier)
Functional Applications:
· Wire & Cable Compounds: Meets IEC 60332 flame retardancy standards (typical dosage 10-15 phr)
· Conveyor Belts: Enhances abrasion resistance (15-20% improvement in DIN abrasion tests)
· Sealing Products: Improves compression set characteristics at elevated temperatures
Technical Benefits:
· Halogen content provides self-extinguishing properties (UL94 V-0 achievable)
· Reduces compound viscosity for better processing (Mooney viscosity reduction by 10-15 points)
· Extends service life in outdoor applications (UV stability improvement)
3. Coatings & Paints (Multifunctional Additive)
Formulation Advantages:
· Intumescent Coatings: Acts as carbonific agent in fireproof paints (15-25% formulation content)
· Marine Coatings: Provides excellent water resistance (salt spray resistance >1000 hours)
· Industrial Maintenance Paints: Enhances adhesion to metal substrates (cross-cut adhesion improvement by 1-2 grades)
Performance Characteristics:
· Lowers VOC content compared to traditional additives (30-50% reduction potential)
· Improves brushability and flow characteristics
· Extends recoatability window without intercoat adhesion issues
Other Uses
· Textile/paper waterproofing
· Metalworking lubricants (anti-wear, extreme-pressure additives)
· Adhesives, inks, sealants