The synthesis methods of EBS can be generally divided into four routes.
1) reaction of stearic acid with amine compounds
2) reaction of stearic acid esters with amine compounds;
3) Reaction of stearoyl chloride with amine compounds;
4) Hydrolysis of nitrile compounds.
Stearic acid method is simple and easy to operate, the reaction conditions are mild and not harsh, the reaction raw materials are easy to obtain and low cost, the yield is high and the three wastes are less, but the ammonium salt intermediates generated in the salt-forming stage are very easy to color, making the product color value high, and the ammonium salt has other side reactions in the dehydration stage, leading to a decrease in product purity and a broadening of the melting range. However, as long as the process control is strengthened, the products produced can fully meet the needs of users; chloride method is characterized by a two-step reaction, simple and easy, mild conditions, but the post-treatment is complex, three wastes, the total yield is relatively low, and does not adapt to the current situation, but the color is good; fatty acid ester and amine reaction can obtain high purity amide, high yield, but the esterification of fatty acids and amidation process of alcohol evaporation process is complex, high energy consumption , is not conducive to the implementation of clean production; cyanide decomposition, although simple, but the preparation of raw materials cyanide is difficult.
Since most EBS manufacturers currently use the stearic acid method to produce EBS, the following discussion focuses on this reaction process.
H2NCH2CH2NH2+ 2RCOOH →
RCOO – + H3N(CH2)2NH3+- OOCR
RCOO- + H3N(CH2)2NH3+- OOCR →
Firstly, in the molten state, stearic acid reacts with ethylenediamine to produce the intermediate ammonium salt (around 100°C), which is extremely easy to color and decomposes above 140°C to obtain the corresponding acetylbis-stearamide. This method has a short process flow, but the reaction temperature is high, generally above 200°C. It is also necessary to select suitable catalysts and antioxidants to ensure that the materials are not oxidized during the synthesis process and to ensure the product chromaticity.
Deqian (Shanghai) Chemical Co., Ltd. charge regulator PW-180 is suitable for epoxy-polyester and polyester-TGI C powder coatings, the dosage is 0.1%~1.0% of the total formula; charge regulator PW 189 is suitable for ring Oxy-polyester and polyester-TGI C powder coatings, the dosage is 0.3%~~1.0% of the total formula. The tribo-charger is used to improve the tribo-charge performance of powder coatings and increase the charge of powder coatings during tribo-electrostatic powder spraying. Electricity, the agent added to increase the powdering rate of powder bed coatings. Most of the powder coatings are applied by electrostatic powder coating wax. Among the electrostatic powder coating methods, one is the corona discharge electrical method to make the powder The paint is negatively charged, and the other is to make the powder paint electrostatically positively charged by the friction charging method. The powder coating of the friction charging method is easily affected by the type and structure of the powder coating resin. Generally, the atmospheric powder coating is easy to be frictionally charged. , Epoxy-poly and TGI C cured polyester powder coatings have poor frictional electrostatic properties. Therefore, if you want to use bad oxygen polyester and TGI C curing polyester powder wood coating for friction electrostatic powder wood coating liquid, you must add friction charging agent in the powder technology coating formula, if the resin manufacturer has already used the polyester resin Add this kind of auxiliary agent, no need to add friction charging agent. The technical indicators of the TB series charging agent produced by Ningbo Nanhai Chemical Co., Ltd. are shown in Table 229. It is dispersed by melt-extrusion mixing method.
Light stabilizer and UV absorber
Light stabilizers are functional additives that can inhibit the aging of film-forming substances and polymer materials under sunlight. There are many reasons for the aging of the coating film under sunlight. The most important reason is the sunlight and the photoaging performance of the coating film. In the phenomena of hair loss, fading, discoloration, cracking, chalking and peeling, adding a light stabilizer can improve the weather resistance of the coating film.
Light stabilizers can be divided into screen-wearing agents, excited state energy scavengers, free radical traps, peroxide decomposers and ultraviolet absorbers according to their principle of action. The most commonly used light stabilizers in the coatings industry are light screen gargles and ultraviolet absorbers. Two or more types of light stabilizers are used in matching light-resistant and attached powder coatings that require certain special properties. The function of the light shielding agent is to make the coating film reflect or absorb ultraviolet rays, reduce the transmission of ultraviolet rays, and protect the inside of the coating film from the influence of ultraviolet rays. The representative ones are rutile white, carbon black, zinc and silica And other pigments and fillers.
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