Green is the new gold, and the trend for all things sustainable means no stone is left unturned in the fight to be the greenest kid on the block. Lena Zak reports on some of the sustainable adhesives and sealants on the market.
Although adhesives and sealants form only one component out of the thousands that are used to construct a building, they have a significant influence on the building’s total environmental footprint.
Sustainable adhesives are those that work to reduce the harm being done to the environment throughout the adhesive’s entire life span. This includes the manufacture of raw materials, the adhesive’s formulation, processing and end- use, as well as its final disposal.
Henkel has recently recognized the market potential in Australia and New Zealand for environmentally friendly and formaldehyde-free, one component polyurethane adhesives and launched the Purbond product line. The odourless adhesive system emits almost no CO2, thereby significantly reducing any impact on the environment and human health.
Purbond makes use of the natural moisture of wood to join timber sections and requires no solvents or formaldehyde. Its higher yield conserves production resources because less adhesive is needed than with other adhesive solutions. It also contains no VOCs (volatile organic compounds) or water-soluble ingredients that can pollute the environment.
While in the past the major drivers for sustainable adhesive development were government regulations, today’s market is driven primarily by the fact that environmental consciousness has entered all of business life in a very significant way.
Although regulations still play an essential role, it seems that many of today’s formulators and end-users are developing a taste for sustainable products because of market trends, as well as the opportunity to reduce costs — including materials, energy, insurance, waste disposal and so on.
In light of these facts, formulator HB Fuller has also released a series of sealants and adhesives that are both sensitive to the user and to the environment, eliminating chemicals such as Isocyanates, which can cause allergic reactions similar to asthma and a staining of the skin called ‘Black Hand’ in the flooring installation industry. The products also contain less than 5 per cent VOC and a low solvent content.
Many adhesives that are based on natural substances have traditionally been viewed as having inferior performance to synthetic petrochemical derived products. However, this is no longer necessarily true, with many advanced sustainable adhesives and sealants having superior properties, such as hydrophobicity, lower viscosity and biodegradability.
According to Edward M. Petrie, author of The Handbook of Adhesives and Sealants, “the major barriers to the widespread acceptance of these raw materials (so far), have been their availability and the cost to produce them.”
With the increasing popularity of wood in construction, such barriers are being dismantled. “The main benefit for designers using wood is that there are no visible bondlines, which allows for an exceptional aesthetic effect. For builders, the benefit is two-fold: curing time is significantly reduced because the system cures as a result of reacting to the natural moisture of wood, and quality bond strength is guaranteed as a result of applied pressure,” says Brad Simpson, Henkel Australia, segment manager AI — Construction.
Henkel’s Purbond adhesives can be used for both structural and non- structural wood applications such as I-beams, glulams, structural insulated panels, cabinets, millwork, finger jointing and face gluing. In addition to the environmental and structural benefits, Henkel believes Purbond adhesives have helped the global market by promoting wood products, often considered more superior to other materials in terms of sustainability and resource depletion.
“Wood is a wonderful construc tion material. It is easy to process, is an excellent insulator and helps create an interior atmosphere that makes people feel comfortable,” Simpson says.
The major components of conventional wood adhesives, which are replaced in sustainable products, are phenol and urea formaldehyde. Formaldehyde, which has been one of the key constituents of wood to date, has been especially targeted for replacement since it contains phenol and resins and is considered carcinogenic. This creates health related problems for both the manufacturers and end-users of wood composites.
As Petrie explains, the replacement of VOCs, formaldehyde and other toxic chemicals containing synthetic wood adhesives will lead to a reduction in the need for woodworkers to construct and maintain expensive ventilation systems to protect workers from VOC intoxication. It will also reduce worker exposure to toxic materials in manufacturing plants, eliminate the generations of toxic waste products and provide health benefits to consumers with chemical sensitivities.
HB Fuller asserts that everyone has a role to play in preserving the environment. With these beliefs in mind, its product releases have included the Floor Bond MS and Floor Bond XMS flooring adhesives — a range of environmentally friendly alternatives to standard polyurethane floor adhesives, forming stable and easy-to-trowel peaks, especially in cold temperatures. These adhesives do not stain hands during or after use and because they do not contain water, they will not deform timber flooring like traditional polyurethane flooring adhesives.
For Katherine Madden, associate director of Pidcock Architecture + Sustainability, the vital factor to be considered in choosing sealants with “as low a VOC level as possible, combined with natural, organic ingredients”.
Pidcock Architecture + Sustainability is an architectural practice with a strong focus on environmentally sustainable design (ESD). The company aims to demonstrate how the many issues that are fundamental to ESD can be potent influences in architecture and the built environment.
Madden explains that the architects “look for products that help prolong the life of the substrate in varying locations, always ensuring that the Materials Safety Data Sheet (MSDS) for hazardous warnings on materials is satisfactory.”
Other factors that play a role in its decision-making process include the levels of pollutants from sealants entering water streams and the manufacturing processes and practices of the sealant manufacturer. Madden also warns that while “there are not a number of water-based sealants available, care needs to be taken to ensure that the green claims on products are actually accurate.” Turning to reliable manufacturers is one step that can be taken to ensure that such claims are realised.
The sustainable building trend refers to an increasingly popular shift from standard building practices, which are typically guided primarily by short-term economic considerations, to ‘best practice’ with an emphasis on quality construction, energy efficiency, indoor air quality and conservation of natural resources.
With many of the modern synthetic adhesives used in this sector being derived from depleting petrochemical resources, going green now really can mean going for gold. And with so many quality sealants now available in the Australian market, a truly sustainable construction sector really is just around the corner.
