Method for lowering curing temperature and anti-skinning of Shuangma resin and modified resin

Abstract

The invention relates to a method for preventing skinning on the surface of bismaleimide resin in curing and lowering the curing temperature of the bismaleimide resin. By adding little ketoxime or ketoxime substance into the bismaleimide resin, the skinning phenomenon when the bismaleimide resin is cured and the problems such as unfairness of the cured article surface and resin injection can be effectively prevented; moreover, after adding little ketoxime or ketoxime substance, the curing heat release peak-to-peak value temperature of the bismaleimide resin is greatly reduced by more than 30DEG C, and the heat release peak is narrowed; after the bismaleimide resin is cured under the same condition, the vitrification conversion temperature (DMA method) can be greatly increased by 40DEG C, and the application advantages of the bismaleimide resin on the aspects of curing resin, paint, cured resin and the like at a low temperature and utilizing the resin, paint, cured resin and the like at a high temperature can be improved through the modified resin.

Description

technical field [0001] The invention relates to a method for reducing the curing temperature of double-horse resin and anti-skinning and a modified resin, belonging to the technical field of thermosetting resins. Background technique [0002] Thermosetting resins have a very wide range of applications, such as cast resins, coatings, composite materials and other fields. Compared with thermoplastic resins, thermosetting resins have higher hardness, strength, heat resistance, and have excellent solvent resistance and processability. As a large category of thermosetting resins, Shuangma resin has also received extensive attention. Its cured resin has excellent heat resistance (the glass transition temperature can reach above 300°C) and mechanical properties, and its cost and molding process difficulty are much lower than those of polyimide resin, which is also a high-temperature resistant resin. The fields with high heat resistance of materials, especially the aerospace field...

AI Technical Summary

Problems solved by technology

By mixing some other substances, such as epoxy resin, benzoxazine and other substances, the curing temperature can be reduced, such as the document "Properties of toughened bismaleimide and allyl benzoxazine blends" ( Gu Yi et al., Aerospace Materials Technology 2012, Issue 5, pp. 45-50) and "Benzoxazine–bismaleimideblends: Curing and thermal properties" (SanthoshKumarKS et al., European Polymer Journal 2007, 43:5084–5096) all reported the use of benzoxazine to modify bismuth The thermal curing properties of horse resin, but the exothermic peak will obviously move to the low temperature section when the addition amount is very high, such as reaching more than 30%, which will inevitably lead to a decrease in the heat resistance of the final resin, and the curing peak span is very large. The termination point is still indistinguishable from the double horse resin used, so in practice a high temperature is still required to achieve sufficient curing

"Synthesis and performance research of solvent-free medium-temperature curing bismaleimide resin" (Ren Hongyan et al., Plastic Industry 2010, Issue 6, pages 1-3, 7) reported that the use of epoxy resin modification to reduce the curing of bismaleimide resin Temperature research, but the addition amount is large (mass ratio 1:1) and there is still a curing peak of Shuangma resin in the high temperature section, indicating that high temperature treatment is actually required to completely cure the resin

[0004] For most allylphenol-modified bis-horse resins, there is also a problem that the free surface will quickly skin during the curing process, and due to the uneven internal curing shrinkage, the surface will subsequently wrinkle and form large undulations , resulting in serious potholes on the surface of the final cast body

However, the reason for the skinning of Shuangma resin is still unclear and there are few reports. It may be caused by surface oxidative polymerization and internal thermal fluctuation and shrinkage, which makes it difficult for Shuangma resin to be directly used as a vacuum for coatings and composite materials. Bag molding and other processes, and it is also easy to form skins during the injection process, making injection difficult

However, most of the current research on Shuangma resin focuses on the synthesis of new resins, formulations and toughening and composite materials of Shuangma resin. There are very few reports on this aspect, and a document that can be retrieved (J.Mater.Sci. 42:9170-9175) involves the doping of a quaternary ammonium salt of an amphiphilic copolymer to reduce the volume shrinkage of bima resin curing, thereby reducing surface shrinkage, but this high polymer needs to be dissolved in a solvent in advance and then Doped into Shuangma resin, the solvent needs to be removed before curing, which increases the steps and difficulty of the molding process

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