Plastic film and sheet processing plants can use new processing technologies to produce high-value daily-use consumer plastic products, while at the same time obtaining higher product prices.
In general, new processing technologies are more economical than existing production process systems. For example, in the K 2004 exhibition, the introduction of a processing system that has been successfully promoted in Japan to Europe has been a successful example. Roberto Boscacci, Marketing and Product Manager at WEKO Biel in Switzerland, said that the company’s coating system has provided film manufacturers with an effective way to replace coextruded films with a single-coated film process, thus saving raw materials. And reduce energy consumption.
"In many cases, coextrusion is not cost-effective or necessary for processing plastic films with surface functional properties," Boscacci said. This new processing system uses multiple rotary atomizers to produce uniform sprays containing functional additives (anti-blocking agents, anti-fogging agents, anti-static agents) in nano- or micro-scale coating thicknesses in series or offline mode Spray it. Boscacci said that these coating thicknesses are sufficient for most applications.
After passing through a smooth roller roll and hot air drying, the sprayed microparticles were even further dispersed on the base film. The film can be processed without temporary storage, which also saves costs.
The number of plates on the rotary atomizer depends on the width to be coated. A cam deflection device with two rotational speeds can be placed in an overlapping configuration to ensure a uniform spray pattern. Spray mist flow requires a viscosity of at least 200 mP. Deep-stretched sheets are prepared for thermoforming films and can also be coated simultaneously with coatings containing different additives (eg, anti-blocking agents are used on the outer layer and anti-fogging agents are used on the inner layer). This reduces processing time. .
The amount of spray coating liquid is very small (1-5ml/m2), so the processing plant can significantly reduce the consumption of additives. Researchers at the Institute of Plastics at the University of Paderborn in Germany conducted testing tests at the Extrusion Machine Manufacturing Company in Esde, Germany, by using slip agents, anti-fogging agents and antistatic agents for polyvinyl chloride, polyester, polystyrene and polyethylene. As a result of the wet coating of the base material, the film can be subjected to a coating operation without pretreatment. Only polyethylene films have an "inert" surface and require corona treatment before they can be effectively sprayed with an antistatic agent coating.
Boscacci said that Japanese processors first discovered that this coating system has the advantage of cost savings, thus eliminating the need for internal and external functional film layers. For the same reason, he said that Kpackner Pentaplast, a German packaging and processing company, has purchased two WEKO production systems, which are installed in factories in the Netherlands and North America. With the advent of the WEKO system, the cost of a processed product was given by processing a 5 μm thick, five-layer coextruded film and comparing it with two layers of a 1 μm thick functionalized spray coating on a three-layer substrate. “If we replace the two outer layers of this five-layer coextruded film (one layer with an anti-fogging agent and one with a slip agent), the processing plant can change the co-extruded film layer without changing the film composition. Count to reduce the total film thickness." Boscacci said.
It is said that this company can save 52.4 thousand euros per year through this production system. And if the energy consumption needed in co-extruded film production is added, the savings will reach 61.4 thousand euros per year.
Source: Foreign Plastics
