Low-oil-permeability high-strength addition-type silica gel and preparation method thereof

Abstract

The invention relates to low-oil-permeability high-strength addition-type silica gel and a preparation method thereof. The addition-type silica gel is prepared from the following raw material components in parts by weight: 100 parts of alpha,omega-vinyl polydimethylsiloxane, 5 to 15 parts of single-ended vinyl polydimethylsiloxane, 15 to 30 parts of polymethylhydrosiloxane H1, 10 to 25 parts of polymethylhydrosiloxane H2, 0.01 to 2 parts of inhibitor, and platinum catalyst containing 0.5 to 50 ppm of platinum by mass, wherein nSi-H / nSi-Vi is greater than 1 in the addition-type silica gel. Theaddition-type silica gel has not only higher tensile strength and elongation at break, but superior oil permeability resistance, and stable adhesive performance and dielectric property, and can meet the encapsulating protection requirements of high-end precise electronic parts and components.

Description

technical field [0001] The invention relates to a silicone gel, in particular to an addition-type silicone gel with low oil permeability and high strength and a preparation method thereof. Background technique [0002] Silicone gel, commonly known as jelly gel, the moles of the two active functional groups silanyl and vinyl groups that play a role in vulcanization in addition-type silicone gels are usually less than 1, that is, n Si-H / n Si-Vi ≤1, generally between 0.2-0.8, its cross-linking density is generally 1 / 2 to 1 / 10 of that of addition-type silicone rubber, and after vulcanization, it is a frozen material with coexistence of solid and liquid, except that it has the properties of general addition-type silicone rubber In addition, its own softness endows the material with low elastic modulus and low internal stress, and has self-healing properties. It can automatically heal after being cracked by external force. When used for device potting, it can not only prevent du...

AI Technical Summary

Problems solved by technology

[0003] The ultra-low hardness of silicone gel endows it with shock absorption and damping properties, but due to the low crosslinking density and insufficient vulcanization degree, it also brings problems of insufficient strength and toughness and easy oil leakage on the surface of the gel. It may lead to the cracking of the colloid, and the seepage of the oil will greatly reduce its dielectric properties and adhesion

In the currently published literature on addition-type silicone gel, silicone resin is usually added to make the silicone gel have good flexibility and strength at the same time, but the elongation is not high and the elasticity is not good.

CN10251677A discloses an addition-type silicone gel for potting precision electronic components, but it cannot guarantee that the silicone gel has good toughness and strength

CN103709988A discloses a silicone gel with good toughness and strength at the same time, but the elongation is not high and the elasticity is not good

CN104212185A discloses a kind of stable and non-oil-seeking addition type silicone gel, which reduces oil seepage by pretreatment of raw materials by falling film evaporator, single-end vinyl silicone oil instead of dimethyl silicone oil as plasticizer, but raw material processing The process is relatively complicated, and the relevant data of its oil leakage have not been disclosed

Images