Coatings World - April 2009

A more sophisticated variation is to use, for example, titanium esters mixed with aluminum flake. The esters can be formulated into the binder system of stoving paints which will resist temperatures of up to 400°C. Above that temperature, burn-off occurs, depositing a titani-um-aluminum complex coating which has good hardness and adhesion, and can resist temperatures of up to 800°C.

Chart 1

“The 35 segments that
make up the global
market for heat resist-
ant coatings is valued
at US$543.9MM and is
expanding at an aver-
age growth rate of
5.78% annually.”

Source: Chemark Consulting

Chart 2

Powder coatings which will resist temperatures of 300-500°C, depending on formulation, have been on the market for several years and are used for applications such as barbecues, stoves and exhaust systems. An important consideration here is that powder coatings are often applied at relatively high film builds, but for these applications the film must be kept thin to minimize thermal stresses on heating.

IMPORTANCE OF PIGMENTATION

As has been noted in the example above, the pigment may react with the binder at high temperatures, making its choice critical. In general, however, there are two main issues:

• The pigment must itself be capable of resisting the service temperature; and

• Flake-form pigments may help to protect the resin system against oxidation.

Thus, leafing aluminum flake is widely used, though at temperatures above 500°C, ceramic frits are preferable. Black iron oxide and some other metal oxides are used in some applications, but care has to be taken not to choose materials that

will lose water of crystallization and/or change their crystal form at service temperatures, as this results in a change of color and possible damage to film integrity.

MARKET SIZE & GROWTH RATES

There are 35 market segments representing 1,152 possible combinations serving this fast growing market (see Table 1).

The 35 segments that make up the global market for heat resistant coatings is valued at US$543.9MM and is expanding at an average growth rate of 5.78% annually.

Broken down in regional markets,

Source: Chemark Consulting

NAFTA accounts for $246.6MM of the global market; all of Europe represents $199.9MM; China makes up $46.33MM; and South America accounts for the remaining $36.85MM (see Chart 1).

Although powder coatings have established a 14% foothold share in the heat resistant coatings market segment, it is not growing as fast as the liquid portion due to the greater technical flexibility with liquid systems versus powder (see Chart 2).