Primer and Adhesion Promoter

TRAPYLEN^® and TRAPUR^® are primer and adhesion promoter systems for coating, bonding, printing and laminating of polyolefinic plastics.

Depending on the application TRAPYLEN^® und TRAPUR^® are ready-to-use products or additives to increase adhesion strength.

Mainly used raw materials are

• chlorinated polyolefins (CPO)
• chlorine free modified polyolefins (APO)
• polyurethanes (PU)

Our products are available as

• solid resins
• resin solutions in organic solvents
• water based dispersions
• UV- curable liquids

Primers are generally used for undergrounds which are difficult to coat and shall be adhere, varnished or coated in another manner. The performance of the primer is defined by adhesion strength and adhesion firmness, which means the power of resistance of a coating to mechanical separation from the underground. There are some DIN and ISO-standards for the performance of primers. By an increase of the adhesion firmness, varnishes obtain a better resistance to chemicals and other environmental influences. Nowadays primers are used for various applications. For the glass coating so-called functionalized silanes or other organometallic bonds (titanates or zirconates) are applied. The coating of plastics, especially of polyolefin, is a specific challenge for a primer (also called plastic spray paint primer). The plastics Polypropylene or polyethylene are materials for automobile manufacturing and are for example used for bumpers of cars.

The bumper is often painted in the same color as the car for design reasons and previously had been coated with a modified polypropylene (e.g. chlorinated polypropylene or acrylate modified polyolefin) as paint primer. Especially chlorinated polypropylenes (CPO) had been used in various applications within the past forty years, for example for plastic paint, foil coating or as additives for the printing ink industry. As a result of this development a great number of delivery forms of chlorinated polyolefin do exist.  For example a solid resin can be directly dissolved in a printing ink. These types of adhesion promoter works often also on other plastics.

Alternatives to primers are corona-, plasma-pre-treatment or flame treatment. For foil coating the corona-pre-treatment is used in particular to reach an optimum wetting of the applied coating on the substrate. A negative aspect of this treatment is the loss of surface tension of the stimulated surface which sinks by and by. The application of flame treatment, especially when using flammable solvent colors or varnishes is very difficult or often not possible because of the open flame.

Our product recommendations and technical advice are based on careful investigation and are to our best knowledge but are without guarantee. Users have to test for themselves whether our products perform properly in their application.