Web特集
September 14, 2009
Series: Focus on Paint Market in Japan
Features of industrial waterborne coating system in 2009
The penetration of waterborne coatings has been late.
The improvement on workability and cost efficiency is needed.
Waterborne coatings have been aggressively developed, however, actual reaction in the market is not so active. It is only applied in certain market field and approved by limited customers. Although waterborne coatings take good advantage from environmental viewpoint, it does not grow popular. That reason seems to come from its poor workability and cost efficiency. Under current recession, new investment for waterborne coating system is rarely expected.
Sudden slowdown in the economy since last fall made a big impact to review Japan production scheme, mainly for export business. The rethink of investment plan heavily affected paint industry, as a result, some big projects for new investment of waterborne or powder coating system were postponed, in the worst case, it was canceled. The market depression may shake the base of paint industry.
Unfortunately readjustment or delay of investment plan by customers did deal large blow to waterborne coating market as well.
In recent years, steel furniture producers mainly approved, applied waterborne coating. As for indoor pollution issue, customers selected powder coating because of formaldehyde free. And concerning many customized colors, waterborne coating is preferably used because powder coatings have a difficulty in frequent color change. Major paint producer said, "The coating segmentation between water and powder depends on how/where customers want to spray".
Other waterborne-coated matters are Cable ledge, Distribution board, Automotive parts (shock absorber, interior part) and Industrial machinery. The market is limited and customers are only few leading companies in each field.
According to current curing conditions classified by the heating temperature, we have two types. One is 120-150 C baking for Steel furniture, Automotive parts, Distribution board and Cable ledge, and the other is 60-80 C drying for Car interior parts, Construction equipment, Heavy machinery and Vehicles (that need thick coat and have high thermal capacity) additionally Plastics parts which is unable to be heated at high temperature.
Regarding used resin binder, Polyurethane, Acrylic, Epoxy resin and other oxidative polymers are used for baking system and for drying coating 2-Component urethane, high solid, Epoxy type are used. Actual resin component is not simple but combined highly. Even if basic formulation of coating is made, each application line needs minor tuning occasionally.
One of main factors in slow penetration of baking waterborne coating is to take time and effort for actual spraying; that means poor workability and need high investment to improve. It is difficult for waterborne coating to standardize coating process, therefore, each time we face the sagging and bubbling problem under high humid, we have practically to change spray conditions or arrange coating formulations.
In addition, the limitation of raw materials leads to high cost. Total cost of waterborne coating is usually 20-50% higher than solvent borne type. Furthermore, some performance such as adhesion, corrosion resistance and appearance on film are still in question.
As top coat on drying waterborne coating, 2-component waterborne urethane is desired. However, it has relatively short pot-life, poor film appearance (as gloss, flatness) and difficulty in cleaning of paint caused by its high viscosity. 2-component waterborne urethane system is not approved because of this disadvantage.
As for primer coat under drying waterborne coating, waterborne epoxy is being developed, but the film performance is not enough yet. Water resistance is too bad, adhesion and anti corrosion property is worse than solvent borne type.
Users of construction equipment, heavy machinery and vehicles try to coat 2-component waterborne urethane coating using current spray line. It takes time to approve the coating formulation. For the time being, they apply high solid coatings with current spray facility. Current high solid coatings have around 80% N.V. and is applied by 1 coat with high gloss, thickness.
Until now, high solid coatings have been recognized as a transitory measure before 2-component waterborne urethane coatings is launched. But it is gradually getting the lead under severe economy situation because existing high solid coatings can meet current VOC regulation, have an advantage to utilize running facility and its film performance is acceptable.
Economic circumstance dramatically changed in the last 6 months, so users were very worried about surplus capacity under depressed demand. They should review the production and supply scheme quickly.
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