Room-temperature vulcanized neutral silicone weather-proof sealant, preparation method and application thereof

Abstract

The invention discloses a room-temperature vulcanized neutral silicone weather-proof sealant which comprises the following components in parts by weight: 160-240 parts of basic polymer, 30-80 parts oflight calcium carbonate, 100-160 parts of heavy calcium carbonate, 3-6 parts of nitrogen-doped graphene, 12-30 parts of simethicone, 8-15 parts of chain extender, 13-19 parts of cross-linking agent,2.5-5 parts of coupling reagent and 0.2-0.4 part of catalyst; the basic polymer is polydimethylsiloxane with two ends terminated by hydroxy; the viscosity of the basic polymer at 25 DEG C is 60000-75000mPa.s. The silicone weather-proof sealant provided by the invention has low tensile modulus, high elasticity, high elasticity recovery rate, excellent weather fastness and excellent adhesive property; after the silicone weather-proof sealant is treated in the manner of cold draw-hot press, water soaking, and the like, the silicone weather-proof sealant is free from interface adhesion failure andcohesive failure; the high-displacement joint filling of the silicone sealant in super high-rise buildings and the sealing for concrete expansion joints of facilities, such as roads, bridges and airport runways, can be promoted.

Description

technical field [0001] The invention relates to the technical field of polymer sealing materials, in particular to a room temperature vulcanized neutral silicone weather-resistant 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 interfacial ...

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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