Low-emission coatings

Note. In any building the above glazing areas may be doubled when double-glazing is used and trebled when triple glazing, or double-glazing with low-emissivity coating, is used. 

The goal of many of these systems is to have automatic control, so that a person does not have to adjust anything with the time of the day or the season of the year. Low-emissivity coatings for glass keep the heat from the summer sun out of the house, and keep heat in the house in winter. Yet there are times when letting the heat in would be a... 

Further, the dislocations in the world oil supply and the resultant discontinuities in petrochemical prices increased the cost of traditional low-solids solventborne systems and the cost of curing higher temperature thermosetting systems as well. The coatings industry responded to these pressures with new technology low-emission coatings. 

The major limitation of this approach to a low-emission coating is the fact that in order to meet Rule 66 requirements the polymer solids must be high and, as a consequence, the molecular weight must be kept low. As a result, water-reducible polymers are restricted to thermosetting vehicles if adequate performance properties are to be maintained. In applications where thermosetting vehicles are required, this is no particular disadvantage since carboxyl and hydroxyl functionality is already present in the backbone to render the polymer water soluble. 

The development of this approach to low-emission coatings has been advanced by the recent perfection of production methods for producing narrow molecular weight distributions. It has been found that unless the molecular weight distribution is quite narrow, the cured film does not develop adequate properties. 

In summary, acrylic industrial coatings have been employed for almost half a century in applications where durability and resistance to the environment are paramount. Over the years, numerous chemical technologies have been developed to achieve specific properties. Because of their versatility and their inherent resistance properties, acrylic polymers have played a central role in the development of coating technology. The growth of new technologies for low-emission coatings has Increased this role even more. 

When polymerization is used as the hardening principle, reactive components combine to form the binder, e.g., unsaturated polyesters with styrene or acrylate monomers. Here, one component often behaves as a reactive solvent for the other, and low-emission coating systems are the result. Cross-linking can be carried out at room temperature (cold curing) or by radiation curing. 

Open-weave liner (Murphy/Jahn Architects, 2006 Holst, 2006). The low-emissivity coating has the effect of blocking the radiative heat exchange between the external membrane surface and internal surfaces whilst reflecting the coolness of the chilled floor (Holst and Schuler, 2003). Without this... 

Yuste M, et al. Correlation between structure and optical properties in low emissivity coatings for solar thermal collectors. Thin Solid Films 2010 518(20) 5720-3. 

Figure 45.8 Cross-section of the granular aerogel-based glazing, consisting of two glass panels with a low-emissivity coating on the inside, two gaps, and an aerogel-filled PMMA double-skin sheet [25].

MEASURING OF VOC-CONTENT IN PAINTS AND VARNISHES 17.1.3.1 Definition of low-emissive coating materials... 

In summary, acrylic resins allow the user or the coating polymer chemist considerable latitude in choosing an acrylic that best meets his requirements. Due to their excellent resistance properties, acrylic resins play an important role in the development of modern coating systems. Acrylic resins also find wide application in the development of low-emission coatings. 

In this section, the requirements to allow polymeric binders to function well in low-emission (high solids, waterborne, and powder) coatings are discussed. The requirements will apply to all of the binder types (including crosslinkers) that were discussed in the previous sections. Along with the features that allow the binders to perform in the low-emission coatings, the limitations that are imposed on the coatings are also discussed. 

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