JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012 - 63

Fig. 1: Applications for 2K coatings: shipbuilding, steel constructions, trains & railways and wind power plants

working on large areas. With manual applications, coating materials must be manually mixed in the proper ratio, allowed to dwell (or «sweat-in») for a given period of time, and then the mixed coating material must be applied before the open time (pot life) of the product expires. Moreover, there can occasionally be considerable material loss – through residues in opened packaging and also through uneven application with the brush. In addition, the consistent quality of the manual mixing is often difficult to consistently reproduce. Last but by no means least, working with such toxic materials represented a health risk for personnel.

Cartridge systems offer convincing advantages
Given its experience with automated dispensing systems, especially with large pack sizes such as those used in the building trade, Sulzer Mixpac was constantly receiving requests from the coatings market. The developers at Sulzer held intensive talks with end-users in order to understand the problems they faced and to find out what they needed. As it proved impossible to meet all the requirements with a single system, two variations were developed: the light, portable MixCoat™ Spray system, and for difficult-to-access areas, the flexible MixCoat™ Flex. Both are easy to use and require very low maintenance. The advantages of the cartridge systems are obvious: - Cost savings: higher material costs incurred by filling cartridges far outweigh the lower labour costs, resulting in significantly shorter working time being required for mixing and applying coatings. - Automated mixing: this yields a much more precise mix ratio which can be reproduced every time. - Precise metering: coatings are applied

evenly for consistent film thickness, with minimal overspray. - Safe storage: the cartridges are extremely stable and can also be resealed easily. - Protection of resources: with each application, only the amount of material that is actually required is used. - Portability: the systems can be used without difficulty wherever they are needed; for example, on-board ships. A complete system is comprised of three different parts: the cartridge, the mixer and the dispenser. Both components of the coating material are stored separately in the side-by-side cartridges. As the material is sometimes toxic, the leak tightness of the cartridge is of paramount importance. In addition, cartridges must be filled without incorporating air so that uniform metering and dispensing is guaranteed. For this, Sulzer was able to call on its own patented technologies. The cartridges are back-filled, while a valve plunger seals the cartridge and prevents air entrapment. At the front, a special outlet system (F-System) ensures that neither component comes into contact with the other before entering the mixer. The cartridges are coded so that they cannot be accidentally connected incorrectly to the mixer, and because the cartridges are easily resealed, opened cartridges can be reused until they are completely empty. There are two advantages to these fea-

tures: first, the material is used as needed; and second, completely empty cartridges are not considered hazardous waste, making them much more economical to dispose of than partially empty containers. The spray mixer is attached to the cartridge at the front and has two functions. First, it ensures that both components bind into a homogenous mixture. To this end, Sulzer uses its tried-and-true QUADRO™ mixing technology. Second, the compressed air in the air-assisted process enables the spray function. There are two options available for the compressed air connections: a standard connection and a “quick lock” connection for a faster and more convenient mixer exchange. Sulzer offers 0° and 90° angled spray tip versions as well. In the latter, the point is designed at a right angle. This facilitates easy spray coating of angled surfaces.

Fig. 3: Spray mixer based on the tried-and-true QUADRO™ mixing technology

The right dispenser for every application
The cartridges and mixer are completed by the addition of the new dispensers, MixCoat™ Spray and MixCoat™ Flex. Typical applications for both systems include 2K coating repair work in shipbuilding, on pipelines, steel constructions and wind power plants as well as on automotive loading spaces or railway cars.

Fig. 2: MIXPAC™ cartridge with patented seal to avoid premature mixing of the two components and incorrect attachment of the mixer

No72 April - May 2012

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JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012