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Li Xiaoqiang, Li Yong, Xie Jing, Lin Xien, Zeng Li, Peng Haomin
Guangzhou Dynasky Materials Technology Co., Ltd.
China Electrical Science Research Institute Co., Ltd.
Abstract: Analysis of the structure and curing reaction principle of dual-official reunification ester resin, the study of powder coating formula dual-official reunification ester resin acid and hydroxyl value, detergent and filler type and content of the effect on powder coating delamination performance. The results showed that the anti-gloss of the coating increased with the increase of the acid value of the double-colloidal reunification ester resin, while the change of the hydroxy value of the double-colloidal reunification ester resin had less effect on the anti-gloss of the coating;
powder coating is widely used in home appliances, automobiles, aluminum profiles and other fields, is mainly high-gloss type, with the change of people's aesthetic concept and the understanding of the dangers of light pollution, light-absorbing powder coating more and more favored by the vast number of users at home and abroad .
, the main anti-light powder coatings used outdoors are acrylic and pure polyester. The principle of de-lighting is basically to make use of the incompatible system, the difference of curing reaction speed, etc. to cause the rough surface on the microscope of the coating film to produce light-down. Acrylic anti-light powder coating decoration and weather resistance is good, but because of the brittleness of acrylic resin, so that the impact resistance of the anti-light coating film is poor; The most common end pyrethroide polyester resin powder coating is the end pyrethroide polyester resin/TGIC curing system, the system's anti-light powder coating gloss is difficult to achieve less than 10%, and the coating leveling and mechanical performance is not very good;
dual-function reunion ester resin has both end-hydroxyl and end hydroxyl, the presence of 2 kinds of hydroxyl groups for the preparation of anti-light powder coating provides more possibilities for formulation changes, can be prepared due to the existence of multiple curing and the formation of cross-link inter-wear network anti-light coating, and this anti-light powder coating can be combined with end-to-end pyride polyester resin and end hydroxyl polyester resin both performance advantages. Based on the curing principle of bi-official reunification ester resin, this paper analyzes the effect of acid value, hydroxy value, type and content of detergent and filler on the performance of dual-official reunification ester resin anti-light coating.
1 Experimental part
1.1 Main raw materials
dual-official energy reunion ester resin: Guangzhou Dynasky Materials Technology Co., Ltd.; TGIC, closed isocyanate (B1530), hydroxyamide (HAA), titanium White powder, anti-light vanadium, high-gloss palladium, precipitation vanadium, leveling agent, resting incense, carbon black, anti-light agent A9, anti-light agent XG628, epoxy acrylic resin HM308: industrial grade, commercial.
preparation of 1.2 powder coatings and coatings
ingredients in accordance with table 1 formulations.
powdering process: ingredients, premixed, extruded, broken, screened, powder coating. The prepared powder coating is coated after electrostation spraying and cured under 200 degrees C/10 to 15min conditions, and then the relevant performance test is carried out.
1.3 Dual-official reunion ester resin curing reaction principle
In the process of double-official reunion ester resin curing process, the closed isocyanate (B1530) first de-enclosed, and then with dual-official reunion ester resin hydroxyl reaction, and TGIC and its niobium-based reaction, and finally cross-linked into the target product, as shown in Figure 1. Dual-function reunion ester resin compared to ordinary end-to-end pyride polyester resin, after curing molecules introduced more urethane bonds, so its chemical resistance is good, and the presence of urethane bonds and the formation of hydrogen bonds between large molecules, so its mechanical properties outstanding.
1.4 Test and Symptoms
Polyester Resin Acid Value by GB/T6743-2008, Hydroxy Value by GB/T12008.3-2009, Viscosity by GB/T9751.1-2008, Glue Time by GB/T 16995-1997 measurement; horizontal mobility measured by GB/T6554-1986; appearance as visual; feel as touch; gloss measured by GB/T9754-2007; red appearance (KBr pressure sheet) by Perkin Elmer Spectrum 65 Fourier Transform infrared spectrometer.
2 results and discussion
2.1 red appearance
dual-ocyn energy reunion ester resin and its transparent coating infrared spectrum as shown in Figure 2.
From Figure 2, it can be seen that the double-official reunion ester resin appeared at 3537cm-1 - OH's telescopic vibration absorption peak, and the double-official reunification ester resin cured transparent coating film appeared at 3398cm-1 - NH's telescopic vibration absorption peak, which indicates that B1530 and dual-official reunification ester resin hydroxyl reaction, present in the molecular structure.
2.2 Effects of acid and hydroxy on the anti-light performance of the coating
Unlike ordinary mono-energy reunion ester resins, dual-ability reunion ester resins contain both end-oxycodone and end-hydroxyl, in order to investigate the effects of acid and hydroxy-values on the anti-light performance of the double-phenolic reunification resin coating, the same hydroxy (25mgKOH/g) different acid values (15mgOH/g) were examined. , 25mgKOH/g, 35mg KOH/g) double-adhesive reunification ester resin and the same acid value (25mg KOH/g) different hydroxy values (15mgKOH/g, 25mgKOH/g, 35mgKOH/g) double-adhesive reunification ester resin in the use of chemical anti-lighting agents, the results can be seen in Figure 3.
as can be seen from Figure 3, in the case of the same hydroxy value, as the acid value increases, the anti-gloss of the coating film also increases. This may be because there are 3 types of curing reactions in this anti-lighting system, the anti-lighting agent and TGIC reaction, dual-function reunification ester resin niobium-based and TGIC reaction, and dual-function reunification ester resin hydroxyl and closed isocyanate (B1530) reaction, the curing reaction speed of the three is not the same, its lighting principle is largely the use of the difference in the rate of triple curing caused by the microscopic rough surface. And with the increase of the two-cell reunification ester resin acid value, the reaction activity of the resin also increases, that is, the reaction speed with TGIC is accelerated, and this may weaken the TGIC and dual-official reunification ester resin, the curing reaction speed difference, resulting in the de gloss with the increase of the acid value. In addition, it can be seen that in the case of the same acid value, with the increase of hydroxy value, the anti-gloss of the coating film basically remained unchanged. This may be because, relatively speaking, the response rate of hydroxyl and B1530 of dual-hydroerphic reunification ester resin is slow, in a certain range, the increase of hydroxyl value, the difference in curing rate of the three has little effect, therefore, with the increase of hydroxyl value, the de gloss remains in a relatively stable range.
2.3 The effect of the type and content of anti-lighting agent on the anti-light performance of the coating
among the most widely used polyester/TGIC coatings in the domestic outdoor light-absorbing powder coatings, there are three ways to eliminate light: wax powder and metal soap, anti-light curing agent and dry-mixing. The principle of wax powder and metal soap de-lighting method is to use wax powder and metal soap and polyester resin incompatible, when curing migration to the surface, so that the coating surface produces microscopic roughness, reduce the reflection of the coating surface, enhance scattering to reduce gloss, to achieve the effect of de-lighting. Wax powder and metal salt composite anti-lighting agent in a certain range of can obtain a better de-lighting and leveling effect, and stable performance, easy to use, so it has obtained a wide range of applications. At present, there are more applications for Ze he's A9 (A9 and TGIC have chemical reactions, the ratio is about 10:1). Outdoor anti-light curing agent can be broadly divided into 2 categories, one is a mixture of polyacids and amine catalysts, such as XG628, a amine-modified polyacid compound, and the other is acrylic co-polymer. Dry mixed light is mainly the use of 2 resin curing reaction speed differences to form a de-lighting effect, this paper is not discussed. Figure 4 shows the effect of the addition on the de-lighting performance of the dual-ability reunion ester resin coating when using A9 and XG628 respectively.
As can be seen from Figure 4, with the gradual increase of the addition of A9 and XG628, the de-gloss of the double-vinyl reunification resin powder coating is gradually reduced, and when the amount added to 4.5%, the gloss tends to stabilize, but relatively speaking, the use of XG628 is lower than the de gloss of the use of A9. This is caused by the difference in the principle of light loss between the two. A9 is a composite anti-lighting agent of wax powder and metal salt, its light-killing principle is more the use of its incompatible with the resin to cause de-lighting, and XG628 is a TGIC curing agent as the object of the anti-lighting agent, the lighting principle is the use of catalyst-containing detergent, polyester resin and TGIC reaction rate, and the catalyst-containing detergent and polyester resin compatible differences, thus forming a de-lighting. In contrast, the use of XG628 than the use of A9, the coating reaction system is more complex, more conducive to dual-dphernation reunification ester resin de-lighting.
acrylic resin has excellent leveling, weather resistance and solvent resistance and other outstanding properties, for this reason, this paper studies the dual-nel reunification ester resin using acrylic resin anti-light effect. HM308 is an epoxy acrylic resin, Table 2 adds HM308 to the dual-phenolic reunification ester resin coating anti-light performance.
Because epoxy acrylic resin is a reaction with the bi-official reunification ester resin, the larger the addition of epoxy acrylic resin, the greater the acid value of the corresponding double-official reunification ester resin should also be greater. As can be seen from Table 2, with the gradual increase of HM308 addition of epoxy acrylic tree, the de-gloss gradually decreases and the coating is relatively flat. However, from the experimental results, the use of epoxy acrylic resin coating anti-gloss is still high, for this reason, consider increasing the complexity of the system reaction to further reduce the de-gloss, Table 3 is HM308 and dual-official reunification ester resin quality ratio of 3:9 HAA dosing on the dual-official reunification ester resin coating de-glossing performance.
by Table 3, with the increase in HAA additions, the gel time gradually becomes longer, the fluidity gradually becomes longer, the gloss gradually increases. This is mainly because the bi-official reunification ester resin's carbidium-based reaction with epoxy acrylic resin, but with HAA reaction speed is higher than the reaction speed with HAA, so with the increase of HAA addition, gel time gradually become longer, fluid gradually become larger. From the principle of de-lighting, the more complex the curing system, the less glazing should tend to decrease, but the experimental results show that the dual-official reunification ester resin / epoxy acrylic system de-gloss is lower than the dual-official reunification ester resin / epoxy acrylic resin / HAA system. This may be because although there are 2 types of curing reactions in the dual-function reunification ester resin/epoxy acrylic resin/HAA anti-light system, but with the gradual increase of HAA addition, it needs to consume a certain amount of niobium base, so the addition of epoxy acrylic resin needs to be reduced accordingly, so although a heavy curing reaction, but not enough to offset the reduction of epoxy acrylic resin to reduce the role of the luster reduction, so its gloss increases with HAA.
2.4 Effect of filler type and content on coating anti-light performance
The experiment examined the effect of the type and addition of filler BasO4 on the de-lighting performance of powder coating. Table 4 shows the effect of different types of BasO4 on the de-lighting performance of dual-ernation reunification ester resin coatings under the same amount of addition (30%).
from Table 4, the coating with high-gloss and precipitated palladium has a lower dulling gloss, a more delicate and smooth feel, and a smoother board. High-gloss radon and anti-light radon are natural radon, precipitation radon is chemical synthesis, the particle size of the three is sorted as: anti-light radon, high-gloss radon, precipitation radon. It may be that because of the small particle size of high-gloss radon and precipitation radon, larger than the surface area, the amount of oil absorption is relatively large, so the gloss is lower. In addition, due to its small particle size, the coating surface is more delicate, so the plate level is more excellent.
5 is the effect of the amount added to the anti-light palladium on the anti-light performance of the coating.
as can be seen from Figure 5, with the gradual increase in the amount of BasO4 added, the de-gloss of the double-zeled reunification ester resin coating gradually decreased, but after the addition amount to 33%, the gloss stabilized. This is because BasO4 particle size is small, has a certain amount of oil absorption, has a certain amount of light-de-lighting, but when the added amount reaches a certain degree, the continued increase in the amount of dosing on the effect of light-down is not obvious, and has a greater impact on plate leveling and mechanical properties.
(1) The study explores the principle of the curing reaction of dual-official reunion ester resin, and determines by infrared that the hydroxyl of
B1530 and dual-official reunification ester resin reacts;
(3) compared with the study of double-vinyl reunification ester resin using wax powder and metal soap anti-lighting method, anti-light curing agent anti-lighting effect, found that the use of anti-light curing agent method anti-light effect is more excellent;
(4) studied the effect of BasO4 on the de-lighting performance of dual-ergonophide resin, and the results showed that with the gradual increase of BasO4 addition, the de-gloss gradually decreased, but after the addition amount to 33%, the gloss stabilized; The effect of high-gloss radon and precipitation palladium on the anti-light performance shows that the use of high-gloss radon and precipitation palladium has a lower dulling gloss and better surface level.
dual-function reunion ester powder coating because its polyester resin contains both end-oxycodone and end hydroxyl, its curing process is more complex, there is double curing, in the production of anti-light powder coating, more factors will have an impact on its anti-light performance. Lower acid values, the use of anti-light curing agent XG628, the use of high-gloss radon and precipitation radon are conducive to better light-down effect.