Vegetable oils are abundant and not very expensive renewable raw materials. Soybean oil is one of the most attractive. More than 20 billion pounds of soybean oils are produced annually in the United States. Less than 600 million pounds of them are used for industrial application. Vegetable oils for making PSAs has a number of advantages, low cost, low toxicity, inherent biodegradability, and fairly high purity.

Soy PSA

• Soy PSAs have a wide range of the properties: peel strengths can range from 0.1 to 8 pli (pound per inch) for a number of applications.
• Soy PSAs have very high content of bio-based materials such as vegetable oils
• Soy PSAs are very environmentally friendly, i.e., do not contain any heavy metal, toxic chemicals, and any volatile organic compounds
• Soy PSAs are readily biodegradable, i.e., do not cause any environmental pollution after their useful lives.
• Soy PSAs are very cost-competitive to existing petrochemical-based PSAs
• Peel & Shear performance equivalent to commodity solvent based PSA’s.
• Excellent performance on Stainless Steel, Acrylic, and Glass. Lower performance on un-treated Polypropylene.
• Comparable adhesive performance Shift Post – Chemical Exposure to Gasoline, MEK, SA 10W-30, Salt Water, and Humidity.
• Cold temperature adhesion (stainless steel) testing was completed. Peels were about 10% of the control – a 90% adhesion reduction
• Xenon-Arc exposure on the adhesive, when applied to a polyester face stock, was evaluated at 750 Hours – a 4 month outdoor simulation. The product had complete adhesion and was unable to remove without breaking

Markets of interest:

• Labels and Graphics

Conclusions

• This formulation of a soybean-based adhesive offers similar adhesion as most commodity solvent based PSA’s to most surfaces. It shows outstanding adhesion on LSE (low surface energy) substrates, with low shear.
• The adhesive on a PET facestock shows 10% adhesion deltas during chemical resistance testing.
• UV cured, soybean-based adhesives should be furthered as a green alternative to typical fossil fuel derived products. This adhesive would foreseeably have large volume applications within the label and decal market due to its robust adhesion properties and low shear.