1. Development of low shrinkage vinyl resin
As a range of unsaturated polyester resins, vinyl ester resins have higher activity and faster curing reaction, resulting in a larger curing shrinkage rate after curing of the vinyl ester resin. Generally, unsaturated polyester resins (including conventional vinyl resins) shrink when cured, and can achieve body shrinkage of about 7-10%. With the improvement of the requirements for high-performance resin technology at home and abroad, it is hoped to find some vinyl resins with lower curing shrinkage, which is a technological breakthrough point that many manufacturers at home and abroad strive to seek in the early 21st century. The mechanism of low shrinkage resin is complicated, and some manufacturers have achieved the goal by adding low shrinkage additive (LPA) in order to overcome the curing shrinkage of the resin, but there are limitations in its application, and more manufacturers are trying to pass the resin. Synthetic methods and molecular design levels to solve this technical problem, ultra-low shrinkage epoxy vinyl ester resin with its sufficient mechanical strength and stiffness, sufficient dimensional stability, heat cycle resistance, corrosion resistance, better performance Meet the requirements of high quality FRP products.
Hydroxyl Modified Vinyl Chloride/Vinyl Acetate Copolymers MVAF
2. Impact resistant vinyl ester resin
The most widely used applications for chemical resistance vinyl resin are corrosion resistant applications. However, since the vinyl resin has more secondary hydroxyl groups, the wettability and cohesiveness of the glass fiber can be improved, the mechanical strength of the laminated product is improved, and the two ends of the molecule are crosslinked, so that the molecular chain is under stress. It can be stretched to absorb external force or thermal shock and exhibit resistance to cracking or cracking. Therefore, vinyl resins are used in some applications requiring high mechanical properties and impact resistance, but conventional vinyl resins still need to be improved in terms of mechanical shock resistance, especially some vinyl resins modified with Fuma acid. Since this type of resin has a high curing crosslink density and a short molecular chain segment between the crosslinking points, the impact resistance is poor. In the synthetic design of these resins, it is required that there are many ether bonds on the main chain of the resin molecule, which can sufficiently improve the impact resistance of the resin. In 2013, another method emerged, that is, by rubber modification, that is, Terminal carboxylated nitrile rubber (CTBN) and nitrile rubber (BNR) toughen methacrylic epoxy vinyl ester resin, after which the domestic and foreign methods have done a lot of work, natural rubber modified ethylene The elongation of the base resin and the like are greatly improved, and can reach 12%.
Generally, the impact strength of vinyl resin is not more than 14.00 KJ/M2, and some 21st century newly developed impact-resistant non-rubber-modified new grade vinyl resin can reach 22 KJ/M2 or more, and rubber-modified vinyl resin can reach 25KJ/ M2, these impact-resistant vinyl resins can be used in some high-impact FRP production, such as sports sleds, sports helmets and so on.
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