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Anti-dripping additive to improve flame retardancy of polymer compounds
Fluoropolymers, especially high molecular weight (HMW) PTFE, provide flame retardancy to polymers used in various industrial applications. PTFE, when incorporated into the polymer compound, reduces the dripping of the polymer upon burning and thereby retards the spread of flames. INOLUB™ I-SAN contains HMW PTFE in a specific physical form that enables the compounder to optimize the loading of the additive.
I-SAN powders are HMW emulsion-polymerized PTFE particles that have been encapsulated by a Styrene-Acrylonitrile (SAN) shell.
The free-flowing I-SAN powder has excellent dispersibility in various polymer compounds. The encapsulation of PTFE with SAN minimizes the pre-mature fibrillation of the PTFE particles during the mixing process.
During compounding, shear is applied to PTFE particles present in the polymer matrix. Due to this shear, high molecular weight PTFE particles form a microscopic node and fibril structure (50 nm fibril thickness).
Fibrillated PTFE without polymer compound
This PTFE structure forms a network in the compound which supports char formation during burning and reduces the formation of polymer droplets. Emulsion-polymerized PTFE is used for this application as it forms significantly more nodes and fibrils than suspension-polymerized PTFE. As a result, the quantity of emulsion PTFE required to provide anti-dripping characteristics to the polymer compound is much less than with suspension PTFE.
I-SAN can be used in many polymer compounds, such as Polycarbonate (PC), Acrylonitrile Butadiene Styrene (ABS), PC/ABS, Poly (p-phenylene oxide) (PPO), Polybutylene terephthalate (PBT), High-Impact Polystyrene (HIPS) and Polypropylene (PP). These compounds can be used to produce molded or extruded articles or as a component of other industrial products.
I-SAN prevents dripping during combustion and enhances the ability of the polymer compound to comply with UL-94 V0.
The typical dosing of I-SAN is between 0.1% and 0.5% of the polymer compound, depending on the requirement for flame retardancy.
| Engineering Plastics | Dosage (%) | |
|---|---|---|
| Acrylonitrile Butadiene Styrene | ABS | 0.2 |
| High-Impact Polystyrene | HIPS | 0.2 |
| Polyamide | PA | 0.2 |
| Acrylonitrile Butadiene Styrene/ Polycarbonate alloy | ABS/PC | 0.3 |
| Polybutylene terephthalate | PBT | 0.3 |
| Polyethylene | PE | 0.5 |
| Polypropylene | PP | 0.5 |
| Polycarbonate | PC | 0.5 |
The INOLUB™ I-SAN additive suppresses dripping and enhances the ability of the FR thermoplastic formulations to comply with UL-94 V0 and 5V standards.
| UL 94 | V0 | V1 | V2 |
|---|---|---|---|
| Burning time once (s) | ≤ 10 | ≤ 30 | ≤ 30 |
| Burning time total (s) | ≤ 50 | ≤ 250 | ≤ 250 |
| Burning of cotton by dripping | No | No | Yes |
INOLUB™ I-SAN is a flame retardant additive that can be considered as halogen free with reference to the IEC 61249-2-21 and JEDEC JC709 regulations.