One of the important applications of unsaturated polyester resins is in the field of anti-corrosion, such as anti-corrosion FRP lining, anti-corrosion coatings, etc. As we all know, the core of unsaturated polyester resin is the product of the condensation of alcohol and esterification, but since then it has buried the hidden danger of not being resistant to corrosion. In terms of solvent resistance and acid resistance, unsaturated polyester resins are competent even when the conditions are not very precise. But in terms of alkali resistance, it is obviously very poor. The ester group is easily hydrolyzed under strong conditions, breaking the main molecular chain and destroying the material. Therefore, the main goal in overcoming the corrosion resistance of unsaturated polyester resins is to improve the hydrolytic stability of the resins. In this regard, the early research results were the introduction of BAPM resins, which were considered to be the most resistant to alkaline hydrolysis.
The general view is that the bulky volume of bisphenol A is blocked by alkaline ions, but it may also be due to the strong power supply of the right group, which reduces the positronicity of the carbonyl carbon atom and reduces the attack of hydroxide detachment. effect. In fact, there are similar results. For example, the use of neomerdiol, or 1,4 dimethanol cyclohexane instead of propylene glycol or ethylene glycol to produce unsaturated polyester, is also considered to have better resistance to hydrolysis stability of the resin, often used as a gel coat resin.
In addition to the choice of alcohol, in recent years, the application of ethylenically unsaturated polyester resin has attracted worldwide attention. It is considered to have not only good corrosivity, but also good overall performance, and the most widely used industrial applications. Their molecular structure is similar to that of MPGM, ME-1, MFE-51, AE-1, DMGS, etc. Because the end groups are capped with double bonds, the ester group is no longer on the main chain of the molecule after crosslinking and curing. This is The reason for the corrosion resistance of this type of resin. Moreover, the blocked double bond is not a double bond of cis and trans acid, but is usually a double bond of acrylic acid or methacrylic acid. They can be self-polymerized or copolymerized with a cross-linking agent, and thus form the main chain of the cured resin, thereby Greatly enhance the corrosion resistance of cured products.