Key Considerations for Selecting PVC Cable Compound Granules

Key Considerations for Selecting PVC Cable Compound Granules

 

I. Core Electrical Properties and Safety Performance

 

These represent the most fundamental and critical attributes of PVC cable compound granules, directly determining whether cables can operate safely.

1. Electrical Insulation Properties of PVC Compound:

Volume Resistivity: Higher values indicate superior insulation performance and lower leakage current.

Dielectric Strength (Breakdown Voltage): The ability to withstand high voltage without breakdown, particularly critical for medium- and high-voltage cables.

2. Flame Retardancy of PVC Compound:

Flame Retardant Rating: A core fire safety requirement, especially in buildings, rail transit, and high-occupancy areas.

Low Smoke Low Halogen/Halogen-Free: Requires minimal smoke and corrosive gases (halogenated hydrocarbons) during combustion while maintaining flame retardancy. Halogen-Free Low Smoke (LSZH) is the mainstream trend for high-end and eco-friendly applications.

II. Physical and Mechanical Properties (Determining Durability and Service Life)

 

Cables endure various mechanical stresses during installation and operation. These properties ensure the structural integrity of the cable.

1. Mechanical Strength:

Tensile Strength and Elongation at Break: Ensures the cable resists tearing or breaking during laying and pulling, while maintaining adequate toughness.

2. Thermal Properties:

Heat Deflection: Resistance to deformation at elevated temperatures.

Thermal Aging Resistance: Retention rate of mechanical and electrical properties after prolonged exposure to high temperatures. This directly impacts the cable's design service life (e.g., temperature ratings of 70°C, 90°C, 105°C, etc.).

3. Environmental Resistance:

Weather Resistance: Ability to withstand aging from UV radiation, ozone, and humid climates—critical for outdoor cables.

Oil and Chemical Solvent Resistance: Essential for cables used in specific industrial environments (e.g., machine tools, chemical plants).

 

III. Processing Performance (Impact on Production Efficiency and Cost)

 

The properties of pellets directly influence the stability, appearance, and speed of cable extrusion production.

1. Rheological Properties and Plasticization Characteristics:

Melt Flow Rate/Plasticization Time: Affects extruder processing temperature, extrusion pressure, surface finish, and production speed. Good processability means fast extrusion speed, smooth surface, absence of crystalline spots, and uniform plasticization.

2. Pellet Morphology:

Pellet Uniformity: Consistent size and shape with no dust facilitates smooth feeding and prevents bridging.

Impurities and Crystalline Points: Contaminants and unplasticized crystalline points severely compromise cable insulation quality, creating potential breakdown points.

 

IV. Long-Term Reliability and Stability

 

1. Migration Resistance: Additives like plasticizers in the formulation should not readily migrate to the surface, causing material brittleness or affecting other components.

2. Compatibility: Excellent compatibility with other cable materials (e.g., conductor shielding, sheathing compounds) to prevent harmful interactions.

 

V. Environmental Compliance and Cost-Related Properties

 

1. Environmental Compliance:

Compliance with regulations such as RoHS and REACH, restricting the use of hazardous substances (e.g., lead, cadmium, specific plasticizers).

2. Material Density:

Under performance requirements, lower density reduces cable weight per unit length and raw material costs (cost per meter).

3. Colorability and Color Stability:

Easy to color, with stable hues during long-term use—no migration or fading.