TAGS: Natural-based Adhesives UV/EB Cure Adhesives
Researchers from POLYMAT Institute at the University of the Basque Country have designed a new pressure sensitive adhesives (PSA) made of 71 percent renewable biological products. The adhesive can be tuned to different strengths using ultraviolet light.
Polymerization of Caster Oil and Black Paper Derivatives
The research team used 2-octyl acrylate derived from castor oil, and piperonal, found in black pepper. The structure of piperonal suggested it could be easily derivatized in two steps to piperonyl methacrylate, a great substitute for other monomers that are more difficult to prepare. Piperonal is already commercially available and produced on industrial scales. Piperonyl methacrylate is readily incorporated in conventional existing production plants. Between 7-10 percent of the world production of polymers—around 300 million tons—uses emulsion polymerization for producing adhesives, coatings, paints, latex, and more, including PSAs.
The researchers blended the two raw materials under the same conditions that would be used in emulsion polymerization. The researchers then performed standard adhesive tests on the resulting polymers to determine that the materials worked as well as commercially available PSAs. They also discovered that by exposing the material to UV light, they could tune the material’s strength, stickiness, and shear resistance.
Fine-tuning of Adhesive Properties through UV light
The tuning of materials’ properties using UV light opened various possibilities, such as dental materials, structural adhesives and coatings that rely on UV-light curing being the possible applications.
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This is an important extension of the previous work to develop bio-content PSA,” said Kevin Lewandowski of 3M corporate research materials laboratory. Researchers have demonstrated the utility of a new bio-based monomer. The UV-mediated cross-linking mechanism is useful for tuning the adhesive properties. UV curing changes sticky pressure sensitive adhesive—good for initial tack and repositioning—into a stronger crosslinked adhesive with better bonding performance.
The researchers managed to synthesize the adhesive in water, which minimizes volatile organic compounds, enhances the overall safety of the process, and reduces costs.
Source: POLYMAT Institute