Closed isocyanate coupling agent and application thereof

Abstract

The invention discloses a closed isocyanate coupling agent used for surface treatment for thermal conductive fillers and a thermal conductive insulating nylon composite material. When the coupling agent treats the thermal conductive fillers, a closed isocyanate group is not unblocked and generates a chemical bonding or physical adsorption action with the surfaces of the thermal conductive fillers. In the melting process, the isocyanate group can be unblocked and chemically reacts with amidogen or carboxyl on a nylon molecular chain end. The thermal conductive insulating nylon composite material comprises 100 parts of nylon, 25-40 parts of modified thermal conductive insulating filler, 5-25 parts of a flexibilizer and 1-10 parts of an addition agent. The materials are added into a high-speed mixing machine for mixing and then are extruded to obtain the thermal conductive insulating nylon composite material. The closed isocyanate coupling agent is used for a nylon substrate and can obviously improve the dispersity of the fillers in nylon. Meanwhile, the closed isocyanate coupling agent plays a role of chain extension, the thermal conductivity of the composite material achieves the operating requirement, the physical and mechanical properties cannot greatly decline, and actual use requirements are met.

Description

technical field [0001] The invention belongs to the field of resin-based heat-conducting composite materials, and specifically relates to a blocked isocyanate coupling agent and its application in processing heat-conducting and insulating fillers and in heat-conducting and insulating nylon composite materials. Background technique [0002] Nylon (polyamide) is a general term for thermoplastic resins containing repeated amide groups—[NHCO]—on the molecular main chain. It has a regular molecular structure and is an engineering plastic with high crystallinity and good comprehensive properties. It is widely used in electronics and electrical appliances. , automobiles, machinery and other fields. At present, with the high performance of electronic and electrical equipment, the miniaturization of automobiles, and the acceleration of the lightweight of mechanical equipment, the demand for nylon will increase. Especially when nylon is used as a structural material, high requirement...

AI Technical Summary

Problems solved by technology

However, as the amount of thermally conductive fillers increases, the physical and mechanical properties of nylon composites decrease; and because the inorganic surface is hydrophilic, it is difficult to wet and disperse in the nylon matrix, and there are hydroxyl groups on the surface, and the surface energy is relatively large. , fillers always tend to agglomerate, and coupling agents are commonly used to modify the surface of thermally conductive fillers

For example, Lin Xiaodan prepared thermally conductive and insulating nylon plastics by blending and extruding nylon 66 and large particle size MgO. KH-560 was used to modify the surface of MgO. When the amount of MgO added was 70%, the thermal conductivity of the composite material reached 1.90. W / (m K), but the tensile strength and bending strength are reduced to 41.4MPa and 70.61 MPa respectively, and the notched impact strength is also reduced to 3.3kJ / m 2 , the physical and mechanical properties of composite materials cannot meet the actual use needs of special fields

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