Discussion on the formulation design and coating process of powder coatings for seaside garden furniture

Wen/Lin Linyi, Wu Guanqun, Yang Jielong
Fujian Wan'an Industrial Group Co., Ltd.
Summary: According to the characteristics of the use of modern garden furniture by seashore (high salt, high humidity, strong ultraviolet light), from the pre-coating treatment to solve the problem of anti-humidity and salt spray of modern garden furniture on the seashore, and from the choice of polyester resin, curing agents, fillers and additives, designed to meet the extreme environment of the outdoor powder coating.
1 Foreword
Chinese traditional furniture is a representative of Chinese home design, it is mostly indoor furnishings. Often in order to reflect the luxury of some royal and private gardens, most use some precious wood, not only increase the cost of use, but also at the expense of the natural environment

. Modern garden furniture continues the design style of traditional garden furniture, but in the material has adopted hardware structure-based and a variety of material combinations to make compared to traditional garden furniture, with better corrosion resistance, anti-aging and so on, its metal components are mostly weather-resistant powder static coating. We communicate with customers on a daily basis, often have customers asked to paint garden furniture in the seafront high temperature, high humidity, air rich in salt environment can not only withstand corrosion, but also in long-term sun exposure conditions have a good anti-aging performance. Below we will be based on the customer's requirements for the product to make a summary of the relevant experiments, and some recipes and data with you to discuss.
2 Experimental Part
2.1 Experimental Materials
Different brands of TGIC curing ultra-weather-resistant polyester resins A, B, C; TGIC curing agent (a foreign brand, short for "import" in this article); T GIC curing agent (domestic 1); TGIC curing agent (domestic 2); filler (precipitated pyridoxic acid, quartz powder, mica powder, ultrafine sulphate); wax; sabbath; titanium white powder (golden redstone type).
2.2 Experimental Instrument
Extruder (Haiyang Electrostation Equipment Co., Ltd. SLJ-32); Sieve Powder Machine (Haiyang Electrostation Equipment Co., Ltd. ACM-10); Aging Instrument (Q-LABQUV/SPRAY); Salt Fog Tester (Smart Electronics Co., Ltd. MZ-60); Electrostation Spray Gun (Golden Horse Coating Optiflex2F); Mixer (Haiyang Static Equipment Co., Ltd. J-50).
2.3 Experimental Method
The resin, curing agent, pigment filler, additive is weighed according to the ratio, and the test sample is obtained according to premixed, melted extruded, pressed, crushed, screened, spray plate (film thickness control at 60-80 m), and finally baking curing (190 degrees C/15min). Because of the particularity of the environment in which the product is used, this paper analyzes the data of wet and hot resistance, salt spray resistance and artificial climate aging.
3 Analysis of the results of the experiment explores the comparative selection of
3.1 material weather resistance
3.1.1 TGIC cured polyester resin selection
the test results show that under the same test conditions, different brands of ultra-weather-resistant polyester resins reflect different resistance to artificial climate aging, we have super-weather-resistant polyester resin A as the experimental material behind us. At the same time, we also found in the course of the experiment, ultra-weather-resistant polyester resin made of powder coating impact test data is poor (most of only 35kg-cm) in the formulation design can consider adding a small amount of flexible agent to improve the impact performance of the coating film.
3.1.2 Curing agent selection
test results show that under the same test conditions, three different TGIC in the formulation reflects different salt spray resistance and aging resistance, but also shows that the quality of domestic TGIC is uneven, some brands of TGIC quality and imports are similar. In view of the stability of the experiment, TGIC (import) was used in subsequent experiments.
3.1.3 Filler Selection
Experimental results show that under the same test conditions, four different fillers in the formulation reflect different salt spray resistance and aging resistance, including the use of mica powder has better weather resistance than the use of three other fillers, and precipitation of sulfuric acid second. However, compared with the model made from the above experiments, we can see the same amount of filler, the use of mica powder will affect the smoothness and gloss of the powder coating, so in the design of the formula can be appropriately added in small amounts, and precipitation of radon sulfate with the use.
3.2 Effect of different pre-treatment of sheets on weather resistance
Through the comparative analysis of various materials in 3.1, we selected ultra-weather-resistant polyester A, TGIC (import), precipitated sulphate, mica powder, Titanium white powder (golden redstone type) as the main material of the formula, and then appropriately add leveling agents, tougheners, adhesion promoters, brighteners, scents, waxes and other additives, to make a high-gloss powder coating for the next step of testing work. Below we will use this powder coating sprayed to phosphating iron plate, electrophoretic iron plate, electrophoretic galvanized plate, electrophoretic aluminum plate, chromium aluminum plate five pre-treatment substrates, compared with its moisture-resistant heat type, salt spray resistance, resistance to human and climate aging, so as to finally come up with a powder coating formula used in the coastal environment and its spray processing process.
test results show that different pre-treatment schemes have a great influence on the salt spray resistance of composite powder coating system. According to Table 4: Phosphate iron plate, electrophoretic iron plate and chromium aluminum plate coated with ultra-weather-resistant powder coating, no abnormality in 1000h salt spray test, 1500h does not pass; The electrophoretic aluminum plate of the coating has no abnormality in the 1500h salt spray-resistant experiment and the 2000h does not pass, and the electrophoresis galvanized plate coated with ultra-weather-resistant powder coating has no abnormality in the 3000h salt-resistant spray test. Therefore, according to the analysis of the experimental results, it can be concluded that: on the iron substrate, after different pre-treatment and then sprayed ultra-weather-resistant powder coating salt spray performance>: electrophoretic galvanized plate >electric swimming iron plate> phosphating iron plate; (Because the thickness of electrophoretic coating film has a great impact on the salt spray resistance of the substrate, due to experimental stability and success rate considerations, this paper uses a 20 m thick electrophoresis plate for testing)
4 summary
The defect of powder coating can be well supplemented by the use of different pre-treated substrates. With the development of powder coating technology, the weather resistance of outdoor powder coating has made great progress. Compared with other common powder coatings (e.g. epoxy, polyester, etc.), the melting temperature and baking temperature are the same and the coating process is similar, but the properties (e.g. chemical and weather resistance) are several times that of ordinary epoxy polyester powder coatings. According to the data, its accelerated weather resistance (sun climate color fastness meter) experiment 5000h, gloss hold rate of 92%-98%, almost no aging, salt spray test 2000h unchanged, durability is expected to reach more than 30 years. It can be foreseen that the excellent pre-treatment process coupled with the composite coating process of ultra-weather-resistant powder coating will greatly extend the service life of beach garden furniture and various ancillary facilities, the application prospects are very broad.
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