UV acrylic preparation influencer geometry

Ultraviolet-cured epoxy acrylic is a widely used prepolymer with strong adhesion, good chemical corrosion resistance, high hardness and low price. According to the structure type, can be divided into bisphenol A EA, phenolic EA and cyclooxide oil acrylic. BPA is the most commonly used and the dosing is the largest. Epoxy acrylic is based on epoxy resin and (methyl) acrylic acid, under the action of the catalyst open ring esterification. The primary factor in the preparation process is the "reaction temperature". The esterification reaction is a heat release reaction, and the last 3 side reactions can cause cross-linking and gel, so temperature control is very important during the reaction process, usually the initial control temperature is around 100 degrees C, the reaction later with the decrease of acid value can be appropriately raised temperature (generally heated to 110 to 120 degrees C) to shorten the reaction time. The relevant studies show that the reaction temperature control is the best at 105 to 110 degrees C, higher than 110 degrees C is easy to cause double-bond thermal polymerization and etherization and other side reactions, the change of acid value at different temperatures and determine the optimal temperature is also 110 degrees C, the reaction optimal temperature should be controlled at 105 to 115 degrees C. The influence of raw materials and ratio is also worth paying attention to, in order to get fast curing epoxy acrylic, to choose high epoxy content and low viscosity epoxy resin, so that more acrylic groups can be introduced, bisphenol A epoxy resin generally choose E-51 (epoxy The value is (0.51±0.03) eq/100g) or E-44 (epoxy value is (0.44±0.03) eq/100g). Acrylic and epoxy feed ratio, in most cases to control epoxy resin slightly excessive, generally excessive about 5%, that is, n (acrylic): n (epoxy base) s 1:1.05, to prevent residual acrylic on the substrate and curing film has adverse effects.
And then the effects of the blocker can not be ignored, the reaction temperature is high, in order to prevent the side reaction, must be added to the inhibitor, and in order to improve storage stability, to prevent dark reaction must be added to the blocker, commonly used blockers are parathylphenol, parabens, 2, 5-dimethyl diphenol, 2,6-dichobutyl toluene, etc., the addition amount is about 0.01% to 1% (mass fraction); The effects of catalysts are also present, catalysts are generally used seramine, seasonal ammonium salt, commonly used triethylamine, N, N-dimethylamine, N, N-dimethylamine, trimethyl pyrethroids, triamphetamine, acetylene chromium, ammonium tetra-butyl bromide, ammonium tetraethyl bromide and so on. The study found that the effect of several catalysts on the reaction rate found that ammonium tetrabutyl bromide had the best effect, and found that the amount of ammonium tetrabutyl bromide was 1%, the reaction 5 to 6h and the catalyst was mixed with acrylic first, and then added by drip, the resulting product had good performance; The effects of ammonium and triethyl pyrethyl bromide were found to have the best effect on reaction rate with ammonium triethyl pyrethrin bromide, and the dosing (based on E-44 epoxy resin) was 0.6% to 0.9%;
the factors affecting its preparation can not but mention the correction. According to
China Coatings Onlineexperts
, epoxy acrylates have excellent comprehensive performance, but also has its disadvantages, so many research at home and abroad are focused on its modified aspects. For example, hydroxyl compounds can be used to react with part of the epoxy base, and then the remaining epoxy base and acrylic esterification reaction to improve flexibility. In addition, it can also improve curing speed, brittleness and adhesion through amine change, polyurethane change to improve wear resistance and elasticity, silicone change to improve weather resistance, heat resistance, wear resistance and anti-fouling. Researchers have developed a method of synthesized epoxy acrylates photosensitive coatings using semi-ester methods, or synthetic epoxy acrylic prepolymers based on bisphenol A epoxy resins, acrylics and toluene isocyanates, with low viscosity and good flexibility There is also a kind of acrylic resin synthesized with lipid cyclic epoxy resin as the basic raw material, which has acrylate group and epoxy group, can occur two polymerization reactions of free-form and cation at the same time, showing good synergy effect, thus expanding the application of ultraviolet curing system. Foreign scholars have studied the introduction of phosphorus-containing compounds into the molecular structure of epoxy acrylic to improve flame retardant properties, and found that when the surface of the polymer burns, the phosphorus-containing compounds expand violently and increase in volume, thus protecting the polymer from heat and flame. Domestic also take epoxy soybean oil and acrylic as raw materials, under the action of catalyst synthesis of epoxy soybean oil acrylic prepolymer, the photoactive prepolymer molecular chain for the fat chain structure, can significantly improve the flexibility and adhesion of the coating.
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