High-temperature-resistant flexible adhesive cured at normal temperature and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant flexible adhesive cured at normal temperature and a preparation method thereof. The high-temperature-resistant flexible adhesive is prepared by adopting bisphenol-A epoxy resin, high-polymerization-degree epoxy resin, polysulfide rubber and organic silicon resin as bonding components, adopting polyamide as a main curing component, and adding inorganic auxiliary materials with different proportions. The high-temperature-resistant flexible adhesive disclosed by the invention has the advantages that a Si-O chain section in organic silicon and a flexible chained structure in the polysulfide rubber are formed by changing grafting positions of the organic silicon and the epoxy resin, so that not only are the high-temperature resistance and the toughness of a cured product improved, but also the consumption of epoxy groups in a process of modification is reduced. The epoxy resin adhesive prepared by the method solves the problems that the cost is high, the purchasing of raw materials is difficult and the modification of the bonding components consumes a great quantity of epoxy groups to cause insufficient curing reaction and further cause reduction of the strength of the adhesive in the epoxy resin adhesive in the prior art. The high-temperature-resistant flexible adhesive has the characteristics that the operation can be carried out under the room-temperature condition, and simultaneously the high temperature can be resisted.

Description

technical field [0001] The invention relates to the technical field of adhesives, in particular to a room temperature curing high temperature resistant flexible adhesive and a preparation method thereof. Background technique [0002] Due to the characteristics of high strength, low price, simple process and excellent comprehensive performance of epoxy resin cured products, epoxy resin adhesives have been widely used in various industrial fields, but at the same time, epoxy resin adhesives also have poor toughness and cured products Problems such as heat resistance limit the application of epoxy resin adhesives to a certain extent. In recent years, the main research content is to graft macromolecular groups on epoxy resin, increase the crosslinking density of epoxy resin, and use the polar groups of macromolecules to react with epoxy groups of epoxy resin to form more Macromolecular modified epoxy resin. Although this method increases the moisture-proof, heat-resistant, and...

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Problems solved by technology

Although this method increases the moisture-proof, heat-resistant, and electrical properties of epoxy resin adhesives, it also greatly increases its viscosity, and the addition of macromolecules also consumes a large amount of epoxy groups. The epoxy resin does not have enough epoxy groups to react with the curing agent, thus reducing the strength of the adhesive

At present, the research on epoxy resin toughened and modified adhesives at home and abroad mainly includes the aspects of toughening and softening adhesives, but there are still many problems, such as Wang Chao et al [China Adhesives, 2007, 16 ( 1): 1-5] Use CTBN (liquid-terminated carboxylated nitrile rubber) to toughen the epoxy resin to form a modified epoxy resin with internal toughening, but CTBN has few cross-linking points, low activity, and difficult procurement of raw materials And the curing temperature requirements are high, and the general use temperature after modification is only 120°C; Sun Shaoyu et al. adopt "room temperature curing high temperature resistant high strength toughness epoxy structural adhesive and preparation method" [CN87100265, 1988, 7, 20] prepared the adhesive Binder, although it can be cured at room temperature and can withstand high temperature of 200 ℃, CTBN is also used as the adhesive component, which also has the above problems. Epoxy groups react to consume epoxy groups. If the reaction is too high, the adhesive components will be cross-linked, which will cause insufficient curing reaction [Yao Xingfang, Zhang Shifeng, Chemistry and Adhesion, 2008, 30 (6): 13-16 ]; The adhesive prepared by Sun Yangxuan et al. using "room temperature curing high temperature resistant flexible epoxy adhesive and its preparation method" [CN1546590A, 2004, 11, 7] also uses liquid end carboxylated nitrile rubber, liquid end Expensive raw materials such as hydroxynitrile butadiene rubber and multifunctional epoxy resin are used as adhesive components; Jiang Bocheng et al. Improving the toughness and temperature resistance of cured epoxy resin adhesives also faces problems such as difficult procurement of raw materials and high prices, and the use of imide curing agents can only be cured at high temperatures, which is to a large extent Limits the application of epoxy adhesives at room temperature

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