bopp self adhesive packaging tape printing coating slitting machine producing clear & color & printed packing tapes.
Development of coating technology
From the analysis of the development situation in recent years, the future development of coating technology may present the following three important characteristics:
l Scraper coating will remain the most important coating method for a period of time in the future, and is developing towards high speed and high solid content;
l The measurement method of measuring size and pressure is widely accepted and developed rapidly;
l New coating methods such as spray coating and curtain coating have received widespread attention, indicating a bright future;
However, the above developments are unlikely to be smooth and must face many technical challenges. High-solid-state blade coating can cause running problems such as scraper marks, large blade pressure, paint deposition on the blade (commonly known as turning) and blade wear. Metering size press coating must face high speed and high solidity. The problems caused by the coating of high content and high coating amount. It includes fog splashing at the exit of the coating roll nip, orange peel paper on the coated surface, etc.; the new coating method also solves the new problems that have not been encountered in conventional coating.
Advances in coating technology
Advances in coating technology require the continuous development of pigments, adhesives and auxiliaries, and coating auxiliaries are becoming more and more important.
As the solids content increases, the viscoelastic properties of the coating become more and more important. The interaction between the various components in the coating results in the structuring of the wet coating and exhibits significant viscoelastic characteristics. It would be beneficial if such a structure of the coating could be effectively broken under shear and recovered quickly after metering. On the one hand, it exhibits good runningability, on the other hand, it has less migration of coating adhesive and good coating coverage. However, at very high solids, the viscoelastic structure does not eliminate to the desired level. As a result, problems that may occur with the above-described blade coating and metering size press coating are produced.
With theoretical breakthroughs and technological breakthroughs, WRRM, which can significantly reduce the viscoelastic properties of coatings, has begun to emerge. The addition of this WRRM not only allows the Coating to exhibit lower viscoelastic characteristics, but also helps to quickly eliminate viscoelastic properties under shear and renders the coating viscoplastic at high shear rates. Such a coating can achieve better blade and metering size press coating runability, and can increase the solids content by 2 to 3%, while the high shear viscosity is the same or lower.
Spray coating and curtain coating require a new coating aid to achieve good runnability. For example, a wetting agent is required in the coating to allow the spray coated coating to drip and stabilize the curtain coated coating curtain. More importantly, spray coating requires a low coating viscosity, and curtain coating requires a suitable coating elongation viscosity and other properties may also require suitable additives to match.
In addition, coating auxiliaries also show a trend of versatility. Rheology and water retention modifiers have some of the functions of lubricants, and even some companies claim to function as water repellents; new lubricants show many of the characteristics of rheology modifiers.
Zhengzhou EAST IMPORT AND EXPORT co., ltd . ( a goulian group of company) a manufacturer and exporter for all kind of packaging machinery , like bopp tape coating machines, bopp tape slitting machines. Bopp tape core cutter, bopp tape core loader etc