Toyochem develops low-odour, low-VOC acrylic adhesive for vehicle and building interiors

Toyochem Co Ltd, the polymers and coatings arm of Japan’s Toyo Ink Group, has launched a new low-odour, low-VOC acrylic pressure-sensitive adhesive (PSA), the Oribain™ EXK 21-046, for use in enclosed spaces such as vehicles and building interiors. EXK 21-046 PSAs not only demonstrate good bonds to metals, plastics, textiles and other substrates, but they are also are capable of reducing total volatile organic compounds (T-VOCs), or the indoor air concentration of a mixture of multiple VOCs, to levels less than one-tenth of that of conventional products. The new low-VOC acrylic PSAs also effectively reduce odour levels, resulting in the increased health and comfort of indoor occupants.

The demand for low-impact interior materials has become a global trend as VOC emission regulations tighten worldwide due to growing public and industry awareness of the importance of indoor air quality. VOCs are suspected to be one of the major causes of sick building syndrome and sensory irritation, so building interior materials made from low VOC-emitting materials are being used where possible. In addition, the rise in electric vehicles and automated driving technology is expected to drive the demand for low-odour, low-VOC materials used in automotive interiors.

“While our conventional PSAs clear the indoor VOC concentration guidelines set by the Japanese government, the newly developed EXK 21-046 system was able to dramatically reduce trace amounts of T-VOCs that remain in standard-type products and to improve air quality,” explains Nao Nakamura, General Manager of Toyochem’s adhesives division. “Toyochem research teams achieved this by developing a material that is not easily retained in the adhesive system and by applying our original polymerisation and compounding technologies to better control viscoelasticity of the adhesive material. This results in a substantial reduction in T-VOC concentrations and lower odour intensity without compromising adhesive performance – a feat that had once been difficult to achieve. We believe the new EXK 21-046 PSA will help to realise indoor living spaces that are healthier for their occupants and for the Earth.”

As depicted in Figure 1, the EXK 21-046 PSA achieves T-VOC emissions rates of 18µgC/g, substantially down from 310µgC/g registered by Toyochem’s conventional PSAs. Moreover, the new PSA system realises a 3.5 grade (clearly noticeable, but still not objectionable) on a 6-grade odour intensity scale, a reduction of 1.5 points from the typical 5 grade (very objectionable) recorded by the company’s standard-type products.