High-CTI-value high-flame-retardant composite film and preparation method thereof

Abstract

The invention discloses a high-CTI-value high-flame-retardant composite film and a preparation method thereof. The high-CTI-value high-flame-retardant composite film comprises a modified PC material layer and two modified PPO material layers, the modified PC material layer serves as a base material layer, the two modified PPO material layers are compounded on the upper surface and the lower surface of the modified PC material layer in a co-extrusion mode to form a three-extrusion composite film; through a multi-layer co-extrusion preparation method, a high-flame-retardant PPO material and a high-flame-retardant PC material are adopted, PC serves as a main base material, the PPO material with high flame retardance and a high CTI value is co-extruded on the surface of the PC, so that a 0.5 mm film reaches the flame retardant grade of UL94-V0, meanwhile, the PPO material on the double-sided surface layer has a function of CTI being 0, and high CTI value.

Description

technical field [0001] The invention relates to a high CTI value and high flame-retardant composite film and a preparation method thereof. Background technique [0002] Polycarbonate PC has the advantages of high impact resistance, heat resistance, good dimensional stability, electrical insulation properties, etc., so it is widely used in auto parts, home appliances, electronic appliances and other fields; The process of gradually forming a conductive path under the combined action of liquid is called tracking. The CTI value is a measure of the tracking sensitivity index of a material, which indicates that the surface of a material can withstand 50 drops of electrolyte under a certain voltage condition without The highest voltage value that forms leakage traces; the CTI value of the material depends on the generation and accumulation of free carbon on the surface of the material. Spark discharge can remove the accumulation and accumulation of free carbon, so the tracking pro...

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Problems solved by technology

[0003] In the prior art, in order to meet the high requirements of material flame retardancy and CTI value, aromatic phosphate flame retardants or sulfonate flame retardants are usually added, but the addition of aromatic phosphate flame retardants usually affects PC resin produces plasticization, which affects the impact strength and heat resistance of PC resin; and the addition of sulfonate flame retardants maintains the heat resistance of PC resin, but the thin-walled flame retardancy of PC resin will be limited. And the CTI value is not high

In the application field of electronic and electrical casings, especially the outsourcing materials of lithium batteries, plastics are required to have a high CTI value and high flame retardancy in many occasions, and due to the exothermic use environment, the material also requires a specific high heat distortion temperature, but There are very few products on the market that meet both requirements

[0004] At present, the characteristics of PC materials are changed by adding flame retardants, which only solves the flame retardant function of materials, but the improvement of CTI value is not obvious, and the requirement of CTI=0 value cannot be achieved by adding other types of additives.

[0005] In the prior art, alloy materials are also prepared with other materials. Although the CTI value of the material is improved, the flame retardancy, high temperature resistance and mechanical properties of the product will be lost to varying degrees, and the expected characteristics of PC materials cannot be achieved. ; and the alloy materials that can be selected by this method are relatively small, which is very limited; at the same time, because other alloy materials are blended with PC, it will affect the temperature resistance of the original PC material, reduce the flame retardancy and mechanical strength of the PC material

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