The effect of TGIC granulation method on the properties of polyester powder coating film

Xu Hongling, Xu Yingxuan, Guo Aiqiang, Wang Jun, Niu Wenjie
Anshan Runde Fine Chemical Co., Ltd.
Liaoning University of Science and Technology School of Chemical Engineering
Angang Group Mining Design Research Co., Ltd. Process Design Research Institute
Abstract: Study of TGIC Synthesis The granulation method of the post-treatment process is: negative pressure melting and crushing method, blowing hot dry method, wet legal grain blowing hot dry method, wet legal grain vacuum hot dry method, and the powder coating made with polyester resin respectively, to test the corresponding impact resistance, heat resistance, adhesion. The results showed that when the same amount of TGIC was added, the performance of TGIC and polyester resin film-forming was achieved by the wet legal grain vacuum-drying legal system, and when the amount was added, the impact resistance, heat resistance and adhesion were 3mm, 565h, 56N/cm2, respectively, and the performance of the paint film reached . The method can recover 115mL ethanol for every 500g TGIC produced, which reduces both environmental pollution and production

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TGIC name (1H, 3H, 5H) - THREE (2, 3 - epoxy propylene) - are triazole-2, 4, 6 -tritone, is a multi-ring compound with good heat resistance, weather resistance, bonding and excellent high temperature electrical properties. The appearance of white crystalline powder, melting range of 95 to 115 degrees C, density 1.33g/cm3 (120 degrees C melt). At present, most of the product is used as a curing modifier for polyester/TGIC powder coatings, Yan et al. also used TGIC for CEPET chaining agent, but also because of the relative molecular mass is small, can also be used as epoxy resin modifier.
powder coating is a typical "4E" (efficient, economical, ecological, energy) coating varieties, the use of 8% per year growth rate. 50% of the world's powder coatings are filmed with polyester resins, and polyester/TGIC powder coatings are cross-cured by arbond-based polyester resins and TGICs. Acid value (KOH) 30 to 70 mg/g, softening point 70 to 110 degrees C, hydroxyl value (KOH) 0 to 5 mg/g polyester resin and TGIC have good matching performance. The performance of powder coating coating film depends on the performance of polyester resin and is closely related to the content of ethanol and epoxy propane in TGIC. Polyester/TGIC powder coatings have no volatile parts in the curing process, so they have excellent weather resistance and yellowing resistance. Excellent cheap grid and good surface effect make it widely used in aluminum profile static spraying. Foreign Perera, Montser-rat and so on on the curing of polyester and TGIC has a certain amount of research, the relevant literature in China is rarely reported. TGIC is synthesized in excess epoxy chloropropane, crystallized in ethanol, and a small amount of epoxy chloropropane remains between the cores of TGIC. Both ethanol and epoxy chloropropane seriously affect the film-forming properties of TGIC and polyester resins, and in order to reduce the content of both in TGIC, four methods of granulation drying are proposed: decompression melting and crushing, ventilation heat drying, wet legal particle ventilation heat drying and wet legal particle vacuum heat drying, and the effect of different TGIC granulation methods on polyester/TGIC powder coating performance is discussed.
1 Test Materials and Methods
1.1 Reagents and Instruments
TGIC (30% Ethanol Content After Crystal Filtration), Anshan Runde; Sabbath: Industrial Grade, Wuhan Silver Color Technology Co., Ltd.; Polyester Resin (CE2098): Industrial Product, acid value (KOH) 30 to 34 mg/g, Zhejiang Tiansong New Materials Co., Ltd. production; leveling agent (GLP588): industrial grade, Ningbo South China Sea Chemical Co., Ltd.; titanium white powder (R902): industrial grade, Komu Chemical (Shanghai) Co., Ltd.
electric thermostat blower drying box: 101-1, Shanghai Luda Experimental Instrument Co., Ltd.; Le-Toledo Instruments Co., Ltd.; Twin screw granulation machine: SET-180, Changzhou Jiacheng Drying Equipment Co., Ltd.; Double screw extruder: SLJ-32, Haiyang City, Shandong Electrostation Equipment Co., Ltd.; Vacuum drying box: DZ F-6050 type, bring your own condensing device, Shanghai Jane Instrument Manufacturing Co., Ltd.; Equipment Co., Ltd.; electrostitive sprayer: NJPC-2003A, Zhejiang Mingquan Industrial Coating Co., Ltd.; Lacquer film impactor: QCJ type, Tianjin material laboratory machine factory; Pull test machine: single-arm number display, Henan Platinum Testing Technology Co., Ltd.1.2TGIC sample preparation
1.2.1 negative pressure melting crushing method
after crystallization filtration TGIC500g heated to liquid under negative pressure, until ethanol-free distillation is placed on a clean white steel plate, translucent liquid TGIC will then harden into a white solid TGIC, and then broken with a crusher to a size less than 5mm after the finished TIC.
1.2.2 blowing hot dry method
after crystallization filtration TGIC500g electric thermostat blowing drying box hot dry finished TGIC.
1.2.3 wet legal grain blowing hot dry method
after crystallization filtration TGIC500g by double screw granulation mechanism granulation, and in the electrothermal constant temperature blowing drying box hot dry finished TGIC.
1.2.4 wet legal particle vacuum drying method
after crystallization filtration TGIC500g with a twin screw granulation mechanism granulation mechanism granulation in a 60 degrees C vacuum drying box drying, until solvent-free distillation is the finished product TGIC.1.3 Polyester powder coating model preparation
finished TGIC and polyester resin and other additives according to table 1 ratio added to the twin screw extruder mixing extrusion, control extruder feed section temperature 100 degrees C, feed segment temperature 180 degrees C, and then high-speed Smash 10min inside the shredder, sieve by the sieve machine to get particle size less than 0.15mm micro-powder, sprayed with electrostatization sprayer to the treated cold-rolled steel plate, control film thickness of 30 to 50 m, placed in the oven 200 degrees C curing 30min, to make a model.
1.4 test and
, volatile and epoxy propane residues were measured using GB/T27807-2011. The impact resistance of the paint film is determined by GB/T1732-1993, the heat resistance is determined by GB/T1740-2007, and the coating adhesion is determined by GB/T9286-88.
2 results and discussion of
2.1 different granulation methods on TGIC density, volatile and epoxy propane residues
TGIC drying is to use wind and heat to remove ethanol and epoxy propane from its molecular surface as much as possible, the looser the particles, the smaller the density, the easier it is to remove ethanol and iclororopane molecules, the lower its content. The indicators before and after drying are shown in Table 2.
From Table 2, it can be seen that the density of negative pressure melting broken legal block TGIC is 1.32g/cm3, the distance between molecules is small, attractive, the molecular surface of ethanol and epoxychloropropane is difficult to remove, the mass score is also high, 0.98% and 0.18%, although the recovery of 110mL ethanol, but its rationalization index does not meet the national standards of TGIC. The wet legal particle vacuum thermal dry legal system TGIC density is 0.76g/cm3 x small, the distance between molecules, attraction is small, its molecular surface ethanol and epoxy chloropropane is easy to remove, the mass score is also low, 0.18% and 0.0046%, respectively, in line with TGIC's national standards. In addition, the method also recycles 115mL of ethanol, which not only reduces environmental pollution but also reduces production costs.
2.2 different granulation methods to make TGIC on the impact resistance of polyester powder coatings
It can be seen that TGIC addition in 7%, 4 kinds of TGIC / polyester powder coating impact resistance performance is good, respectively, 6, 4, 4, 3mm, which is due to TGIC and polyester resin curing, paint film has the characteristics of multi-structure and high cross-link density, so that the paint film in many aspects show unique performance. The more mass fractions TGIC adds, the greater the crosslink density and the better impact resistance. When the addition of TGIC reaches 7%, cross-link density, performance reaches. TGIC additions continue to increase, no more hydroxyl-containing polyester resins and TGIC cross-linking, so that cross-link density gradually decreased, so the impact resistance gradually decreased. In addition, in the same amount of TGIC addition, wet legal particles vacuum thermal dry legal system TGIC and polyester film resistance is better than the other three methods, which is due to wet legal particles vacuum thermal dry legal system TGIC volatile and ethylene chloropropane content is low. TGIC and polyester film when the low boiling point of ethanol and epoxy chloropropane with the temperature increased molecular thermal movement, molecular elasticity increased, they will continue to break through the viscosity of the melt to reach the air, and the melt surface to form pores, the lower its content, the fewer pores, the better impact resistance.2.3 different granulation methods to make TGIC on the thermal resistance of polyester resins
the experimental results of polyester powder coating heat resistance are shown in Table 4. It can be seen that the heat resistance of TGIC and polyester resin film-forming is better than the other three methods when the same TGIC is added, which is due to the dispersion of TGIC particles, volatile parts and epoxy propane mass fraction of wet legal particles vacuum thermal drying. Low, 0.18% and 0.0046%, respectively, TGIC's triglyceride ring structure and hydroxyl-containing polyester resin cross-link density is increasing, resulting in lower ethanol and epoxy chloropropane mass fractions at low boiling point, the fewer pores. TGIC and polyester film cross-close more high, paint film heat resistance is better.
TGIC added mass score at 7% when the paint film heat resistance reached a high, respectively, 450, 520, 520, 565h, due to the increasing cross-link density of TGIC added mass fraction, when TGIC added quality When the elasticity of the gas molecules reaches 7%, the viscosity of the gas molecules is balanced with the viscosity of the polyester resin, the paint film surface is smooth and the paint film performance is good, and when they break through this balance, the cross-link density is decreasing, leaving pinholes on the paint film surface, which makes the paint film's performance decrease and the heat resistance decrease.
the effect of TGIC on polyester resin adhesion from different granulation methods
the results of the polyester powder coating adhesion experiment are shown in Table 5. It can be seen that the adhesion between TGIC and polyester film is better than the other three methods when the same TGIC is added, which is due to the dispersion, volatilization and epoxy of TGIC particles in wet legal particle vacuum thermal drying. Chloropropane content is very low, low boiling point of ethanol and epoxy chloropropane with the temperature increase of molecular thermal motion, gas molecule elasticity is less than the viscosity of the resin, so that their cross-link density, paint film surface smooth, paint film adhesion is excellent. When TGIC adds a mass score of 7%, the adhesion of the four methods is 29, 52, 53, 56N/cm2, all of which are values, due to the triglyceride ring structure and hydroxyl polyester when the addition of TGIC increases. Resin cross-linking density is increasing, when the added mass fraction reaches 7%, TGIC and polyester resin just completely cross-link, paint film adhesion, TGIC addition continues to increase when there is not enough hydroxyl-containing polyester resin cross-linking with it, paint film adhesion will gradually decrease.
3 Conclusion
By discussing the effects of different TGIC granulation methods on polyester/TGIC powder coating performance, the following conclusions can be drawn:
(1) the content of TGIC volatiles and epoxy propane in the vacuum heat-drying legal system of wet legal particles is very low, the physicochloropropane is in line with national standards, and 115mL of recoverable ethanol per 500g TGIC is produced, reducing both environmental pollution and production costs.
(2) When TGIC adds quality scores that increase, impact resistance, heat resistance, adhesion increases, and when the added quality score reaches 7%, the performance decreases.
(3) TGIC using wet legal particles vacuum heat dry legal system in the polyester / TGIC system to add a mass score of 7%, impact resistance, heat resistance, adhesion is 3mm, 565h, 56N/cm2, paint film performance.
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