Choice of barium sulfate may directly affect the printing quality of the powder coating. This article will analysis mainly from the use of heat transfer powder coating requirements and manufacturing technologies , and combined with production technology and properties of barium sulfate, summarizes the selection of barium sulfate, to achieve the goal of improve heat transfer powder coating performance.
Barium sulfate have two kinds of precipitated barium sulfate and natural barium sulfate (heavy barium sulfate). In chemistry, they are the same in substance,both of them is barium sulfate.Natural barium sulfate is barite ore, through ore dressing, washing, crushing( grinding) process, such as barium sulfate containing impurities which without the national standards.The precipitated barium sulfate is produced by chemical precipitation of pure barium sulfate, the purity of 98% or more, with the national standard.
Because the chemical inertness of barium sulfate is very strong, so it’s simple to choose precipitated barium sulfate than to choose ultrafine barium sulfate, the main consideration when choosing precipitated barium sulfate is the following indicators : oil absorption (as small as possible), optical bao (the higher the better), particle size (small and uniform), white (the white the better), etc.
Natural barium sulfate is barite ore, the ore dressing, washing, crushing (grinding), and other process.From the perspective of mineral processing to analyze, the higher purity of barite ore, the higher purity of natural barium sulfate. According to the analysis of washing process,natural barium sulfate can be divided into pickling barium sulfate and washing barium sulfate (superfine barium sulfate), and the purity of pickling barium sulfate is higher than washing barium sulfate. Analysis from the grinding process, grinding particle size as evenly as possible, the fineness of grinding will according to different customer requirements to produce more than 600 mesh to 5000 mesh of natural barium sulfate, the smaller grinding fineness, the better gloss retention.So different minerals with different process to produce different natural barium sulfate,and the quality difference is very big, the price has obvious difference.
Below we learn the process of transfer printing on aluminium profile.
The first step: spraying pretreatment;
the second step: to powder of artifacts, curing. Curing conditions of 200 ℃ / min
the third step: stickers;
the fourth step: vacuum transfer printing, thermal transfer conditions: 180 ℃ / 5 min,
the fifth step : tore down a transfer paper.
From the manufacturing technique,the powder coatings for transfer process on aluminium profiles undergo high temperature production two times, so the barium sulfate performance is an important index of heat-resistant, the higher purity, the better heat resistance.
More,the surface roughness (flow flat) of heat transfer powder coating is good or bad will directly affect the effect of heat transfer printing and tearing, so the particle size of barium sulfate and oil absorption are important measure indexes.For highlight coasting, we’d better to choose barium sulfate with small fineness and uniform particle size , to get good film gloss and flat. For the flatting coating, we’d better to choose barium sulfate with finess (600 mesh &800mesh )and uniform particle size. For the extinction coating should be chosen in 600 mesh and 800 mesh fineness and uniform particle size . About Oil absorption,the smaller the better. So choose a suitable barium sulfate for transfer printing powder is extremely important.
Barium sulfate is added to the powder coating can improve the coating hardness, rigidity and scratch resistance and other physical and mechanical performance, at the same time improve the storage stability ,friability and electrification.Therefore, in order to guarantee the quality of coating, it is necessary to use high purity barium sulfate as a filler.Befor barium sulfate into your storehouse, using 10% hydrochloric acid solution to test whether calcium carbonate is in it or not. Calcium carbonate will reduce the weather resistance of coatings.
According to the above information, we offer our sugguestion as follows:
for extinction heat transfer powder coating on aluminium profiles: XT - 206
for 80-90 degrees highligh heat transfer powder coating on aluminium profiles: XT - 306
for more than 90 degrees high heat transfer powder coating on aluminium profiles: XT - 108, precipitated barium sulfate.
If you want to know more about our industry grade barium sulphate , please consult our brochure, or visit the Xintu Chemical (www.xintuchemical.com) website which provides accessible and engaging information on the key role barium sulfate plays in enriching the world around us. Xintu chemical publishes regular articles on how barium sulfate is used across a range of applications, from paints, inks, paper, plastics, food, cosmetics, ceramics, fibers, rubber and many more.
