Bonding agents commercial products

Proprietary bonding agents are used almost exclusively in modern manufacturing processes for metal-rubber bonded products. Isocyanates were proved to be of value in the immediate postwar period, but their moisture sensitivity and tendency to be wiped off the metal during processing have proved as disadvantages. The majority of commercially available adhesives in use today are a complex mixture of undisclosed composition, and in many instances are specifically used for particular rubbers and substrates. 

From this detailed classification, two broad categories emerge, namely those which employ etch-and-rinse and those which are self-etching. Examples of each are shown in Table 5.3, which lists a representative range of current commercial products, with details of the number of steps that each involves and their mode of action. These basic types of bonding agent are now considered in detail in the following sections of the chapter. 

The introduction of a reactive functionality into the polymer, such as unsaturation, offers the potential to use organic acids as coupling agents, but mixed results have been reported. A number of potentially suitable unsaturated products exist, notably, maleic acid and anhydride, acrylic and methacrylic adds, and unsaturated versions of fatty acids such as oleic acid. The acidities and double-bond reactivities of these compounds widely vary depending on their structures, and this probably accounts for the marked differences in their performance. Compounds such as acrylic acid have both high addity and high double-bond reactivity due to the proximity of the carbonyl group to the double bond. The only commercial products specifically developed for use with filled polymer systems are from Lubrizol Advanced Materials (SOLPLUS). 

The colored fraction from crude (FF grade) wood rosin decolorization does not have a generic name. The only material of this nature commercially available at the present time in the United States is the Hercules product, Vinsol. It consists of more than 50% phenolic components and about 25% resin acids and derivatives. Vinsol has a wide diversity of uses, which include emulsifiers for asphalts, tackifiers and bonding agents in adhesives, air-entrainment agents in cements, components of electric insulation, resin extenders in laminates, and foundry cores. 

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