Flame-retardant formulations for PVC insulated cable materials

Flame-retardant formulations for PVC insulated cable materials can be designed differently depending on user needs, flame-retardant requirements, and physicochemical properties. Currently, commonly used halogen-free flame-retardant formulations use raw materials such as magnesium hydroxide, talc, aluminum hypophosphite synergist, and calcium carbonate. Halogenated systems mainly use bromine and antimony trioxide (ATO), but the price of ATO may remain high. Developing cost-effective flame-retardant agents or antimony trioxide substitutes for PVC has broad market application prospects. Below, we will briefly explain a flame-retardant formulation and preparation process for PVC insulated cable materials.

I. Raw Materials and Formulation

PVC Resin: 100; Stabilizer: 24.5; Pentaerythritol Esters: 28; Flame Retardant: 5; Trioctyl Trimethicone: 10; Lubricant: 2; Chlorinated Paraffin: 5; Antioxidant: 0.5; Stabilizer: 13; CaCO3: 6;

II. Production Process

1. Sieving: The PVC resin powder is sieved through a sieve of a specific mesh size to remove mechanical impurities and fish-eye defects.

2. Mixing: Stabilizer, flame retardant, lubricant, plasticizer, etc., are added to a reactor and stirred evenly. The mixture is then ground in a sand mill, controlling the fineness. After filtration, it is transferred to a storage tank and stored under stirring for later use.

3. Pigment Grinding: The pigment is impregnated with plasticizer, stirred evenly, and then ground in a three-roll mill to fully disperse the pigment and improve its coloring power.

4. Kneading: The metered PVC resin, colorant, and prepared slurry are fed into a high-speed mixing kettle and kneaded under heat to ensure uniform mixing.

5. Plasticizing: The kneaded material is then fed into an internal mixer for further mixing, followed by open mixing in a roller mill to fully plasticize the material.

6. Pelletizing and Packaging:

The market demand for flame-retardant cable materials with low heavy metal content, no lead or chromium, and low smoke and halogen-free properties is increasing year by year. The stabilizer in the formula is mainly calcium-zinc stabilizer, which effectively reduces the decomposition of PVC. Insulating flame-retardant cable materials have extensive applications in wires and cables, communication cables, and transportation cables.