Advancements in adhesive technology from Ashland Specialty Polymers and Adhesives, a business group of Ashland Performance Materials, Dublin, OH, USA, a division of Ashland Inc. (NYSE: ASH), led to a discovery that solved a problem called latex blushing. This whitening effect, associated with clear labels, results from minute water pockets that form in the gaps left between the adhesive particles that are used to adhere the label. Once in the ice, trapped water refracts light, causing the area behind the label to look milky.
Ashland scientists recognized that by reducing the adhesive particle size the gaps also would be reduced. By making the pockets smaller and utilizing an agent that reduces water sensitivity, latex with good blush resistance was developed. The new adhesive eliminates the whitening effect of latex when exposed to water because light is no longer refracted at a visible frequency.
“Ashland's advances in water blush resistance provided a step toward chemistry with a more favorable environmental profile to be used in place of traditional solvent-based products, which tend to release volatile organic compounds into the atmosphere,” says Scott Harvey, a research fellow for Ashland Performance Materials. “By using a water based adhesive we are reducing the potential for negative impact on the environment.”
A research paper entitled, “Aspects of Latex Particle Size Control for Improved Water Blush Resistance,” was presented and written by Harvey and co-authored by Gary Carlson, principal development chemist for Ashland Performance Materials, at The Philadelphia Society Symposium on May 6, in Horsham, PA, USA. The paper was one of 12 technical papers presented during the symposium.