Zirconate coupling agents have very similar structure to the titanates. They also perform similar functions. Zirconium compounds exist in both water and organic solvent soluble forms. Like the titanates, zirconate coupling agents are useful in improving the dispersion characteristics of fillers in polymer systems. Examples of zirconate coupling agents and their applications are given in the table above. Bonding is a so-called "special process", meaning that testing cannot be achieved completely by non-destructive methods. Therefore, an understanding of the bonding process must be mastered to avoid errors. DIN 2304-1 [5] (Adhesive Bonding Technology - Quality Requirements for Adhesive Bonding - Part 1: Bonding Process Chain) specifies the requirements for a quality-compliant design of load-transferring adhesive bonds along the bonding process chain - from development through production to reworking. Adhesive bonds are not only subject to certain aging characteristics, but their properties are dependent on the particular environmental conditions, in particular the temperature. Also, both the adhesion-forming interactions between adhesive and substrate, as well as the inter-intramolecular interactions causing the cohesion, can be adversely affected by external influences (including temperature, humidity, chemicals, radiation, mechanical stress). The degree of impairment depends on the nature of the conditions and their duration; this process is called aging. Therefore, when planning a bonding operation, in addition to the actual environmental conditions, their possible long-term effects on the adhesive and substrate must also be taken into account. Nonreactive Products are ethylene Copolymers of ethylene and acrylates (EMA, EEA, EBA) or terpolymers containing also Carbonmonoxide (CO) and/or Vinylacetate (VA). The most recently developed organometallic coupling agents are the aluminates and zircoaluminates. These are conceptually similar to silanes and titanates and find limited use in highly specialized applications. The aluminates appear to be used primarily in adhesives.

Today, the most vehicle manufacturers supply replacement plastic parts with a pre-treatment(primer) which benefits the repainting process. This way, professionals receive parts that are ready for applying the finish paint directly. Similar to this Organometallic Compounds family, patented metal-organic structure offers similar results. It should be noted that the bond to the organic polymer molecule is more complex than the bond to the inorganic substrate. It is important that the chemistry of the organosilane and polymer be well matched for optimum properties. For example, an epoxy silane or amino silane will bond to an epoxy resin, an amino silane will bond to a phenolic resin, and a methacryl silane will bond to an unsaturated polyester resin.Industrieverband Klebstoffe e. V.: manual adhesive technology. Vieweg, Wiesbaden 2016, ISBN 978-3-658-14529-3 . PR-1523-M is an adhesion promoter to enhance the coupling characterics of polyurethane compounds to neoprene surfaces. Zirconates compounds are generally based on alkoxy or neoalkoxy zirconates or zirconium propionates Mono- and diphosphate esters have been used as adhesionpromoters in bonding acrylic adhesive on metals and as a primer for aluminum bonded with epoxy. Hydrolysis must occur to render the silane active for coupling. Proper moisture conditioning of filler or addition of extra water will help assure that the silane hydroxyls and couples.

Various paint adhesion promoters exist and each family has its own properties. Also, these classes can be further adapted to fit the formulator's requirements. However, it can also happen that the new plastic part does not have this previous coat of primer, which in turn will influence the painting process. You will need to apply an adhesion promoteror plastic primer to optimise the anchoring of the subsequent coats. Free radical cure systems: crosslinked polyethylene, peroxide cured elastomer, polyester, polyolefins, EPDM, urethane, alkyd In general, instantaneous bond strength is not achieved. However, pressure-sensitive adhesives used in double-sided adhesive tapes, rapidly curing "superglue" cyanoacrylate, and many light-curing adhesives do achieve significant initial strength after completion of the joining process or very shortly thereafter, although not their ultimate strength required for further processing of the glued assembly.Hermann Onusseit: Practical knowledge of adhesive technology. Volume 1: Basics. Hüthig, 2008, ISBN 978-3-410-21459-5.