Metallic effect powder coating
Last Update: 2020-06-19
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< br / >'me < br / > talicpowercoatings < br / > ZHU Weibing (Ningbo Chengxiang plastic powder Co., Ltd.) < br / > Abstract: This paper introduces the application of aluminum powder, pearlescent powder, copper gold powder and other pigments in powder coating, and summarizes the preparation process and formula technology of metal powder< br / > 1 preface < br / > metal effect powder coating (hereinafter referred to as metal powder) is more and more widely used in the whole decorative coating, which is the mainstream of art powder at present< br / > there are many kinds of metal pigments that can be used in powder coatings, which are generally divided into four categories: aluminum silver pigment, pearlescent pigment, copper gold pigment and other metal pigments (such as nickel powder, stainless steel powder, etc.)Each kind of metal pigment contains a lot of color productsWhen applied to powder, it makes the powder colorful and greatly enriches the variety and decoration of powder coating< br / > metal powder is mainly used in indoor and outdoor metal furniture, lamps, handicrafts, lampblack machine, baby carriage, sports equipment and other industries< br / > according to the survey, most of the metal powders in the domestic powder coating market have quality problemsFirst, the color and pattern between batches are unstable, and second, the spraying performance is poor< br / > like other powders, the development, production and spraying of metal powders also have their own rulesNext, according to the types and production processes of metal powders, we will discuss one by one, and at the end of this paper, we will introduce the new process of producing metal powders - hot bonding technology< br / > 2 aluminum silver powder < br / > aluminum powder pigment can be divided into floating type and non floating typeWhen floating aluminum powder is added into powder coating, it can form continuous phase on the surface of coating after baking, sometimes with mirror effectDue to its unique scintillation, non floating aluminum powder does not present continuous phase in powder coating, but flashes alone like stars< br / > 2.1 scintillation non floating aluminum powder < br / > the particle size of this aluminum powder is usually > 20 μ m, and the surface is generally coated with siliconeThe larger the particle size of non floating aluminum powder is, the better the scintillation effect isBecause of its surface coating, it has good acid and alkaline resistance and certain outdoor durability< br / > the powder coating with non floating aluminum powder can spray the washing machine shell, motorcycle engine shell and other high demand workpiecesThe addition ratio of post mixed non floating aluminum powder is very wide, and the amount of 10% or so has no great influence on the powder spraying performanceAt present, the non floating aluminum powder widely used in domestic powder factories is PCR series products of German aika company< br / > 2.2 the application of floating aluminum powder in powder coating is more popular < br / > the floating aluminum powder is mostly thin under high-power microscope, the average particle size is generally < 20 μ m, the smaller the particle size is, the stronger the metal sense is, and the larger the covering power is< br / > the most powerful metal sense should be chromium plating effect, which is the most popular metal powder in the current marketThe development and production of chromium plating effect of powder coating must start from the selection of base powder formula and aluminum powder, formula 1 can be used as a reference< br / > Formula 1 < br / > raw material name remark < br / > p606045dsm resin, acid value 55mgkoh / g < br / > e-1225 epoxy resin, Huangshan Jinfeng < br / > glp5035 leveling agent, Fenghua Nanhai < br / > benzoin0.5 defoamer < br / > TiO2 3.5 rutile titanium dioxide < br / > wax0.5pe wax < br / > baso421 ultrafine barium sulfate < br / > cblack0.0012 carbon black < br / > Formula 1 uses p6060, because the melting viscosity of the resin is very small, The base powder produced in combination with E-12 epoxy has high levelness and lusterThe function of wax is to improve the scratch resistance of powder surface< br / > in order to get the mirror effect, it is necessary to select the appropriate aluminum powderPC100 of aika company and al2081 of benda-lutz company are recommendedGenerally, the addition ratio is 1.5%If the addition amount is too high, it is easy to produce the phenomenon of powder spitting and gun head blockingIf the amount is too low, there is no mirror effect< br / > for other sizes of floating aluminum powder (mostly 10-20 μ m), the addition ratio of 1.5% - 2.0% can also get very good silver effectThis kind of aluminum powder is added in a small amount (e.g., < 1%)Due to the small amount of aluminum powder, the bottom powder can not be fully covered, and there are often blooming phenomena and sometimes small stripes< br / > 2.3 fine art powder coating mainly adopts floating aluminum powder < br / > the fine art powder here mainly includes sand grain, hammer grain, wrinkle (continuous paint) and crack and other powder coating The typical fine arts powder is black bottom silver flower, and the bottom powder is hammer pattern According to the production process, there are two main methods to produce hammer pattern powder, one is adding floating agent after the other is internal extrusion hammer pattern agent < br / > when the art powder is produced by adding floating agent after spraying, the pattern is easy to adjust, but the beauty is poor, the uneven pattern distribution is easy to occur in the spraying process, and the recovery and utilization of the powder is also very difficult < br / > if the technology of internal extrusion hammer pattern agent is mastered properly, regular and beautiful patterns can be obtained, and the three-dimensional sense is strong, the patterns in all parts of the workpiece are relatively uniform, and the powder recycling rate is high See formula 2 for the recommended formula < br / > formula 2 < br / > raw material name remark < br / > polyester 56 low acid value mixed polyester, acid value 35mgkoh / g < br / > e-1224604 epoxy, equivalent 750, Huangshan Jinfeng < br / > cab-551-0.20.045 cellulose acetate, Eastman company of the United States < br / > wax0.3pe wax < br / > filler 20 can choose calcium carbonate or barium sulfate < br / > cblack1 blue phase carbon black < br / > because it is an internal extrusion hammer agent, the pattern is basically shaped in the extrusion stage, So it is very important to control extrusion conditions The melting point of acetobutylcellulose is about 140 ℃ Different extrusion temperature has obvious influence on its dispersion The proportion of acetobutylcellulose in the powder also has great influence on the pattern Generally, when the amount of acetobutylcellulose is less than 0.035%, the pattern will be large and easy to expose the bottom; when the amount of acetobutylcellulose is more than 0.08%, the pattern will be small and stable < br / > Add 0.3% ~ 0.5% floating aluminum powder to the above-mentioned bottom powder, such as Su Renke's pp1170, to get the effect of black bottom silver flower with clear pattern, clear black and white, strong three-dimensional sense < br / > formula 2 is high gloss metal powder Matte metal powder is also very popular, but there are technical difficulties in producing matte aluminum silver powder with large and beautiful patterns If the internal extrusion method is used, the flow of hammering agent during dispersion and curing is limited due to the high viscosity of the base powder, so the pattern is usually irregular and small < br / > therefore, the development of matte aluminum silver powder with large and beautiful patterns must be adjusted on the bottom powder The method can be used is to add some hydroxypolyester into the formula, and use the incompatibility between it and epoxy resin to reduce the addition of matting agent, so as to reduce the viscosity of the bottom powder properly, or add low viscosity carboxyl polyester such as ce1099 of tianshong into the formula, Generally, only 15% - 20% ce1099 can be added to obtain a larger pattern The reference formula is shown in Formula 3 and formula 4 < br / > formula 3 < br / > raw material name remark < br / > e-1250 epoxy resin, Huangshan Jinfeng < br / > el-120025 hydroxy resin, Guangzhou south < br / > 603-1a4.5 matting agent, Fenghua South China Sea < br / > wax0.3pe wax < br / > baso420 crude barium sulfate < br / > cblack1 carbon black < br / > formula 4 < br / > raw material name remark < br / > e-1255 epoxy resin Huangshan Jinfeng < br / > ce-109920 low acid polyester, tianshong group < br / > p-684.8 matting agent, Zhaoqing Lingan < br / > wax0.3pe wax < br / > baso419 crude barium sulfate < br / > cblack 1 carbon black < br / > the baking conditions of formula 3 and formula 4 are 200 ℃ / 10min (metal substrate temperature), and the luster of the base powder is less than 5% < br / > the above two kinds of base powder can easily get larger patterns after mixing with aluminum powder and floating agent, but there are slight differences in stereoscopic sense and pattern shape It is suggested to use sulenke's aluminum powder pp1170 with the addition ratio of about 0.5% The amount of floating agent depends on the situation It is very important to choose the variety of flocculent It's better to crush more flocculent at one time, use a coarser screen to screen and retain more coarser powder < br / > 2.4 other fine arts powder (sand grain powder or continuous paint) < br / > generally, the effect is not obvious after adding aluminum silver powder, because their patterns are very fine, the aluminum powder can not be fully oriented, and the shininess is weakened or inhibited to varying degrees The production of this kind of art powder is relatively easy < br / > 3 pearlescent powder coating < br / > pearlescent pigment has the Pearl flash effect similar to natural shells, fish, birds and so on, which can not be replaced by conventional pigments < br / > the first pearlescent pigments are made of fish scales, and then there are synthetic silver chloride, basic lead carbonate and arsenic compound pearlescent pigments successively Due to the toxicity of these pearlescent pigments, the range of use is strictly limited < br / > the pearlescent pigments widely used now are series of mica titanium and mica iron, which have the characteristics of non-toxic, good light stability, rich color phase and excellent comprehensive performance < br / > pearlescent pigments are rich in hues, which can be roughly divided into four categories: silver white, iridescent (interference color), golden yellow, metal color (bronze, Zaohong, purplish red, ancient copper, etc.) < br / > when adjusting the formula, the technicians of the powder factory must consider the stability of the color and particle size of the pearlescent pigment, otherwise it will affect the color and quality of the final product < br / > there are many suppliers of pearlescent pigments Merck in Germany is the representative in foreign countries, and Changzhou Huazhu pigment company is the representative in China < br / > several typical powder formulations of pearlescent pigments are introduced here Considering the influence of the price of pearlescent pigments on the powder cost, some pearlescent pigments of Changzhou Huazhu are used for analysis < br / > 3.1 bronze hammer powder < br / > high gloss type, the bottom powder is the same as formula 2, then mixed with pearlescent pigment f-052, the dosage is 0.8% ~ 1.0% < br / > for matte type, formula 3 or formula 4 is used as the base powder, followed by pearlescent pigment f-050 (dosage 0.5%), or f-052 (dosage 0.8%), and flocculent (dosage 0.5%) < br / > 3.2 pine green hammer powder < br / > high gloss type, the bottom powder is the same as formula 2, add pearlescent pigment g-035, the dosage is 0.8% ~ 1.0% < br / > for the matte type, formula 3 or formula 4 is used, pearl pigment g-035 is added, the dosage is 1.0% ~ 1.4%, and the dosage of flocculent is 0.6% < br / > 3.3 Purple Satin hammer powder < br / > high gloss type, the bottom powder is the same as formula 2, adding pearl pigment g-019, the dosage is 0.8% ~ 1.0% < br / > for matte type, formula 3 or formula 4 can be used as the base powder, pearl pigment g-019 can be added, the dosage is 1.2% ~ 1.5%, and the dosage of flocculent is 0.5% < br / > 3.4 golden sand grain powder < br / > black sand grain is used as the base powder, and the recommended formula is reference formula 5 < br / > formula 5 < br / > raw material name remark < br / > polyester 58 low acid value pure polyester, acid value 35mgkoh / g < br / > t105m3.2hmma curing agent, Fenghua Nanhai < br / > pv-880.12 silica adsorption type pure leveling agent < br / > tf-18301.5 sanding agent, Germany Lubrizol < br / > wax0.6pe wax < br / > bp-8811.2 organic bentonite < br / > baso435 precipitates barium sulfate or barite < br / > cblack1 carbon black < br / > the above-mentioned bottom powder is directly mixed with 2.5% pearlescent pigment h-030 to obtain elegant and rich gold effect < br / > there are many kinds of pearlescent pigments, which can easily transfer out powders of various colors The silver white series pearlescent pigments have worse scintillation than non floating aluminum powders Pearlescent pigments should be selected as far as possible when strong acid-base resistance is required In addition, pearlescent pigment should be preferred in the case of good weather resistance < br / > 4 copper gold powder < br / > the copper gold powder used for powder coating does not contain gold in fact, and its main component is copper Due to the doping of different proportions of zinc or tin, a variety of color phases can be obtained After being added to the powder coating, the gold effect can be seen from soft to rough < br / > copper gold powder has soft light, friendly color, simple and beautiful appearance, and is mostly used for painting metal furniture, lamps and crafts < br / > in addition to the color phase, the heat resistance of copper gold powder should be considered Copper gold powder pigment can be directly mixed with the base powder, and the addition proportion depends on the specific situation Its color and flash are weaker than pearlescent pigment < br / > 5 technical points of metal powder coating < br / > 5.1 tips for selection of metal pigment < br / > floating aluminum powder should not be used in occasions requiring alkali resistance < br / > < br / > < br / > according to the existing experience, aluminum powder and copper gold powder should be imported products as far as possible, so as to better ensure the stability of powder quality < br / >
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