Eurailmag - #15 - March 2007 - (Page 13)

Coatings THE GRAFFITI ARMS RACE IS WIDENED IN SCOPE VOC-reduction in other process steps But it’s not only the paint: degreasing and cleaning can also cause solvent emission, which can be reduced by more ecologically and labour friendly systems, but it takes longer. Pre-treatment isn’t a process step to bargain with, anyway. A problem that arises with globalisation is the introduction of cheaper Chinese and Indian fat types, which pose problems in standardising or optimising degreasing procedures. Some maintenance shops keep up to 12 or 15 types of degreasing agents in store. How to foil the graffiti taggers The coatings industry faces numerous challenges that also affect the railway maintenance sector. Coatings ideally should be applicable to a variety of metals, should withstand rigorous graffiti removal treatments, and the waterborne variants should be at least equal in their durability properties and color retention over time. Foils are increasingly in use, because of the trend for using passenger wagons to display for commercial messages. The graffiti arms race is widened in scope, because nowadays, damaging public property or collectively used equipment isn’t limited to spraying paint, but also includes carving with knives, and even setting on fire. A remark was made about overly protecting surfaces by spray can paint repellent coating systems, which might provoke damaging the wagon in more destructive ways. Cleanability could be a wiser strategy in this respect. By increasing the density of the molecular network, the penetration of graffiti ink from markers and paint from spray cans is reduced, and resistance to removal agents increases. Foils should be perfectly applied, without loose edges that might attract vandals. An adhesion promoting base coat might come in handy, in case the foil is a permanent application. Obviously, this type of paint shouldn’t fall in the wrong hands… For foil glue producers, their product must stick to polyester better than to metal, but this is difficult. Removing foil sometimes leaves glue residues on the surfaces, which is a major setback. Sandwich foils consist of a printed base foil covered by an anti-graffiti top foil. Temporary foils used as event announcements or advertisements, have the advantage of offering a short-lived surface for the graffiti message anyway. On the other hand, though not mentioned at the conference, taggers might be inspired to add moustaches and such like on faces depicted on the foil. (Also not mentioned, but perhaps quite effective: selling spray cans over the counter as opposed to off the shelf, thereby reducing the amount of stolen graffiti spray in use). Topcoats with extreme low surface tension, might cause graffiti paint to peel off the surface. The tagger, on the other hand, might decide to continue painting on the floor or windows. Graffiti application trends also represent an arms race, e.g., throwing paint balls off bridges, resulting in wide scale and thick layered paint contamination. One speaker regularly buys graffiti paint, and even disguises himself in jeans so as not to reveal whose side he is on. He discovered solvents in graffiti paint that are phased out in some EU countries, making it even harder to introduce effective counter measures for cleaning purposes. Once he came across a double barreled, two-component graffiti gun, a contraption against which he hadn’t yet developed an adequate counter measure. Even more serious was talk during coffee breaks of technicians at railway maintenance shops, or research departments, being bullied to the extent their names are written in airbrush paint on the trains, plus personal threats, too. Learning from other sectors New developments focus on reducing the number of paint layers, which sometimes balance off higher product prices of the systems involved. For instance, one epoxy silicon at a solvent level below 10% can be applied in two layers, instead of three. Systems with good weatherability that also don’t yellow over time, with a solid content of over 90%, also prove their worth, as do High Solid Polytyurethanes with good UV-stability and a solid content of over 80%. Very durable polysilxanes are in use for painting railway bridges. Powder coatings have been applied successfully for decades, e.g., to coat metal furniture parts. A cataforese, electro-coat filler based on a waterborne, two-component EURAILmag Business & Technology Issue 15 http://www.kremlin-rexson.com http://www.kremlin-rexson.com

Table of Contents for the Digital Edition of Eurailmag - #15 - March 2007

SOMMAIRE
NOTICE BOARD
COATINGS
NEWS
SERVICES
INFRASTRUCTURE
HIGH-SPEED LINES
TUNNELS
PEOPLE
ROLLING STOCK
WEBSITE DIRECTORY

Eurailmag - #15 - March 2007

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