Polypropylene is a popular type of polymer substrate used by many manufacturers of various types of goods. Polypropylene provides durability combined with flexibility as well as chemical resistance properties. Some blends can perform as well as acrylonitrile butadiene styrene (ABS).
It can be challenging bonding polypropylene whether low-density or high density, due to the low surface energy. Surface energy, or surface tension, determines the “wettability” of a surface and dictates how well that surface receives printing or adhesion. Polypropylene typically has a surface tension of 29 millinewton per meter (mN/m), whereas a surface energy of at least 36 mN/m is required to achieve proper wetting or adhesion.
Bonding Polypropylene with Surface Preparation
Pretreating polypropylene surfaces is recommended prior to bonding with some industrial adhesives due to the low surface energy. There are various ways to pretreat polypropylene to prepare for bonding:
- Flame treatment – flame treating is done with specialized equipment that retreats a polypropylene surface to alter the surface energy without altering shape or other properties. This is best suited for flat sheets of polypropylene and requires an investment in the equipment which can be large or bulky.
- Plasma or corona treatment – the surface treatment puts an electric discharge over the surface of parts and is better suited for intricate components. The electronic discharge activates surface electrons which makes them receptive for bonding polypropylene with industrial adhesives. This equipment can also be costly.
- Prime the surface – customized chemical coatings can be used to activate the surface to be receptive for bonding polypropylene with industrial adhesives.
Bonding as soon as possible after surface treatment often provides consistent, quality results.
Industrial Adhesives Solutions for Bonding Polypropylene
Manufacturers wanting to improve their adhesion process involving polypropylene should consult with a custom coatings and chemical manufacturer like Universal Chemicals & Coatings, Inc., UNICHEM. UNICHEM has been providing adhesion solutions for more than 50 years with high quality, industrial adhesive uniBOND, customized to meet your specific requirements. uniBOND is available for bonding polypropylene, lamination bonding for metal, rubber, vinyl laminate adhesives and more.
uniBOND by UNICHEM is proven in many applications bonding polypropylene or polyethylene films and insulative cores to various substrates such as steel, tinplate, or aluminum. uniBOND provides bonding solutions in many applications such as consumer goods, building products, tractor trailers, transportation, and others. uniBOND is available in single stage or two-stage curing formulations.
UNICHEM has been an industry leader in custom coatings and adhesives for over 50 years. We partner with our customers to develop customizable, real-world adhesives solutions in our high-tech, research facilities. Contact us for solutions to your most challenging adhesive problems and experience the UNICHEM difference for successful and cost-efficient bonding polypropylene applications.