Low-modulus room temperature vulcanization neutral silicone weather-proof sealant and preparation method and application thereof

Abstract

The invention discloses a low-modulus room temperature vulcanization neutral silicone weather-proof sealant. The low-modulus room temperature vulcanization neutral silicone weather-proof sealant is prepared from, by weight, 160-240 parts of basic polymer, 30-80 parts of light calcium carbonate, 100-160 parts of coarse whiting, 3-6 parts of graphene oxide, 12-30 parts of dimethyl silicone, 8-15 parts of chain extender, 13-19 parts of cross-linking agent, 2.5-5 parts of coupling agent and 0.2-0.4 part of catalyst. The basic polymer is polydimethylsiloxane with two hydroxyl terminated ends, and the viscosity of the basic polymer under the temperature of 25 DEG C is 60,000-75,000 mPa s. The silicone weather-proof sealant has the low tensile modulus, high elasticity and high elastic recovery rate, excellent weather resistance and good adhesive property; after cold-drawing, hot-pressing, water immersion and other treatment, no interface bonding damage or cohesive failure appear, high-displacement jointing of the silicone weather-proof sealant in a super high-rise building is promoted, and concrete expansion joint sealing of facilities such as a road, a bridge and an airport pavement is facilitated.

Description

technical field [0001] The invention relates to the technical field of polymer sealing materials, in particular to a low modulus room temperature vulcanized neutral silicone weatherproof sealant and its preparation method and application. Background technique [0002] Modulus is the ratio of stress to strain in a material under stress. The modulus of fully vulcanized silicone sealant can be divided into three types: high modulus, medium modulus and low modulus. The displacement capacity of low modulus silicone sealant can reach +100 / -50, it has the advantages of large permanent deformation, high elastic recovery rate, excellent adhesion and weather aging resistance, etc. It can be used for super high-rise building joint filling, Sealing of concrete expansion joints of large concrete facilities, roads, bridges, airport runways and other facilities. Due to its high modulus and low tear strength, medium and high modulus silicone sealants are prone to cohesive failure or inter...

AI Technical Summary

Problems solved by technology

Chinese patent CN 106833503A "A low-modulus one-component deketoxime type room temperature vulcanized silicone sealant and its preparation method" provides a deketoxime type low modulus silicone sealant, although its modulus is 0.24 ~0.30MPa, which meets the modulus requirements of low-modulus sealants, but the surface-drying speed is slow, between 40-130min, which is not advisable in practical applications; although a small amount of white mineral oil added can play a role Reduce the modulus and increase the elongation, and the amount of white mineral oil is not large, but after the aging of the environment, the white mineral oil will slowly seep out of the sealant and pollute the substrate

The methylvinylbis(ε-caprolactam-based) silane chain extender and aminooxysilane crosslinking agent used in it have high reactivity, but the source is limited and expensive, so it is difficult to use in large quantities in the production process

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