LED packaging with silicone material status

one The classification of the silicone material silicone rubber ( 硅橡胶) , hereinafter referred to as silica gel, it is to point to the main chain consists of alternating silicon atoms and oxygen atoms, molecules side chain of organic groups such as methyl and phenyl of polymer materials. The molecular chain has a special machine inorganic silica gel material structure, a combination of the dual advantages of both organic and inorganic materials, excellent high and low temperature resistance, weather resistance, arc resistance, electrical insulation and physiological inertia characteristics. Organic silicone materials according to the chemical structure of the silica gel materials and curing mechanism of product form can be divided into the following several types: silica gel according to the curing temperature, can be divided into high temperature curing silicone ( HTV) And room temperature curing silicone ( RTV) ; According to the product form and the mixed mode, mixing type of silica gel and can be divided into liquid silicone; According to the cross-linking reaction mechanism, and can be divided into condensation reaction, addition reaction and organic peroxides. Then according to reaction type, a brief introduction of the silicone material. 1. Condensation reaction type type of silica gel, silica gel condensation reaction in general is based on hydroxyl-terminated poly siloxane polymer, polyfunctional silane and siloxane as crosslinking agent, under the effect of catalyst, the room temperature water vapor or blender can happen condensation reaction, form the three-dimensional network of elastomer. The basic component of condensation reaction silicone and chemical function as shown below. Room temperature curing adhesives to take off the alcohol, for example, the curing mechanism is: the hydroxyl silicone oil seal end polycondensation (and crosslinking agent. Formation of alkoxy sealing side) , prepolymer contact after the moisture in the air, reactive partially hydrolyzed to generate hydroxyl silicon, the silicon hydroxyl and has not yet been based polymer hydrolysis condensation reaction, removing low molecular, accomplished by chemical crosslinking of polymer chain between curing. Condensation silicone production device according to the types of crosslinking reaction by-products, condensation type silica gel and can be subdivided into acid type, take off a ketone oxime, take off the alcohol, take off the amine, acetone, amide type of six kinds of types, common the advantages and disadvantages of three kinds of condensation silicone as shown below. Condensation silicone building sealant, used as a general lighting devices, such as automobile headlights sealed with antifouling materials, electrical insulator, etc. 2. Plus molding silicone and silicone molding is based on vinyl polysiloxane polymers, including Si - H bonds of polysiloxane as crosslinking agent, in the role of platinum catalyst addition reaction, the three-dimensional crosslinked structure of the silicone rubber. Platinum silicon catalytic hydrogen addition reaction diagram and molding silicone is mainly composed of base polymers, crosslinking agent, catalyst, reinforcing filler and functional additives. Because add silicone molding has low shrinkage rate, no small molecules released during the process of crosslinking, the advantages of excellent high and low temperature resistance, the current LED encapsulation adhesive for the vast majority of forming silica gel, aiming at forming silica gel, the back has a detailed introduction. 3. Peroxide trigger type silicone peroxide silicone, peroxide as curing agent, and the foundation of the vinyl polymer crosslinking reaction to get 3 d mesh three-dimensional structure. Peroxide caused by silicone, there are two obvious drawbacks: one is the need to use more expensive high purity of silane monomer as raw materials and intermediates, 2 it is due to the presence of peroxide in the silica gel, lead to air will seriously affect the solidification, inert gas protection are required for curing, so the production and use cost is higher, it also limits its application scope to a great extent.

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