Thixotrope for packaging LED (light emitting diode ) chip

Abstract

The invention discloses thixotrope for packaging an LED (light emitting diode ) chip. The thixotrope is prepared from a component A and a component B, wherein the component A is prepared from 60 parts by weight of vinyl-terminated silicone oil, 2-7 parts by weight of polyvinyl silicone oil, 3-8 parts by weight of a thixotropic agent and 0.1-0.3 part by weight of a catalyst, and is obtained by evenly mixing the raw materials; the component B is prepared from 0-30 parts by weight of the vinyl-terminated silicone oil, 20-50 parts by weight of MQ-type vinyl silicone resin, 10-20 parts by weight of a chain extender, 2-5 parts by weight of hydrogen-containing silicone oil, 1-2 parts by weight of a thickening agent and 0.01-0.05 part by weight of an inhibitor; the thixotrope is prepared by evenly mixing the component A and the component according to the weight ratio of 1: 1, and defoaming under the vacuum condition. The thixotrope provided by the invention is high in thixotropic index, can be adjusted and controlled, is high in elasticity, tensile strength and tear strength after vulcanization, and is good in light transmittance. The thixotrope is applicable to a dispensing packaging technology of the chip of an LED lamp filament, and has good shape preserving capacity after dispensing and during curing.

Description

technical field [0001] The invention relates to the field of addition-type organic silicon encapsulation glue, in particular to a thixotrope used for LED chip encapsulation. Background technique [0002] Common encapsulation adhesives include epoxy, polyurethane, and silicone. Addition-type liquid silicone rubber has the advantages of convenient processing and molding, no by-products in vulcanization, no corrosion, low shrinkage, and aging resistance and weather resistance. Applied to the packaging of electronic and electrical components, it can protect against moisture, corrosion, and shock. At the same time, the service life of electronic appliances is improved, and it is recognized globally as a new material that can be used in the field of electronics industry. Addition-type liquid silicone rubber is widely used in the packaging of chips in LED lamps. For example, the filament of LED filament lamps is a bracket that connects LED chips in series, and is packaged with sil...

AI Technical Summary

Problems solved by technology

It has been reported in the literature that organic bentonite is used as a thixotropic agent to prepare thixotropic glue. Due to the difficulty in dispersing bentonite with a flake structure, the light transmittance is reduced, and it is not conducive to the dispersion of phosphor powder in the later stage, which will cause uneven color temperature.

There are also reports in the literature on single-component thixotropes. Although they do not need to be further mixed before use and are easy to handle, the storage stability of the thixotropes is poor, requiring frozen storage, which increases the cost of storage and transportation.

[0004] According to public information, the mechanical properties of thixotropes are generally low. The basic range is that the tensile strength is 3-6MPa, the tear strength is 3KN / m, and the elongation at break is basically 100%-200%. Using this type of thixotrope The packaged filament has poor resistance to cold and heat shocks, and the rate of glue cracks and dead lights is high, which weakens the protective effect of thixotropic glue on LED chips.

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