The adhesion of reinforcing textiles in the rubber industry has long been achieved through various approaches, including the modification of the textile by primer coating and surface treatment. Many approaches have dealt with the modification of the rubber combined with complementary treatment of the textile fibers.[i],[ii] Resorcinol Formaldehyde Latex (RFL) treatment is still the most popular process to treat fiber for rubber applications. However, using RFL presents environmental and processing challenges during manufacturing steps. Most RFL treatments require a multi-step process, and its shelf life limits productivity and reproducibility of results.
In the continuing effort to promote more environmentally friendly and easy-to-use products, aqueous dispersions of functionalized low-molecular-weight hydrocarbon polymers (AqFLPs) have been developed.[iii] Table 1 summarizes the physical and chemical properties of the dispersions. AqFLPs show good stability, low viscosity and small particle size. The development of these aqueous dispersions can allow for a wider range of waterborne applications including textile and other substrate treatment. They can also be used in a number of other surface modification areas, including adhesive and coating applications. When properly formulated into surface treatments, the dispersions can increase rubber adhesion to textile, metal and plastic substrates, improve chemical resistance, and affect more homogeneous dispersions of polar fillers in non-polar rubber and plastics.[iv] The hydrophobic and hydrophilic components of the dispersions allow for interaction between polar and non-polar substrates. With the addition of aqueous AqFLPs to styrene butadiene (SB) and styrene butadiene vinyl pyridine (VP) emulsions, excellent compatibility was observed and improvement in adhesion was demonstrated. The blends were homogeneous, grit free and showed good stability.