Adhesion to Rubber and PVC

Manufacturers Comments Flexible. Outstanding adhesion to PVC, ABS and rubber. Euremelt series resins may be blended to produce a range of properties. The flexi)le, series 2000 resins have much better adhesion to rubbers and plastics than Witeo Euremelt 900 and 1000 series. 

Chlorinated rubber is also used to promote the adhesion of solvent-borne CR adhesives to metals and plasticized PVC. Addition of a low molecular weight chlorinated rubber (containing about 65 wt% chlorine) improves the shear strength and creep resistance of polychloroprene adhesives [75] but a reduction in open time is also produced. A heat reactivation (process in which the surface of the adhesive film is raised to 90-100°C to destroy the crystallinity of the film and allowing diffusion to produce polymer chain interlocking more rapidly) restores tack to the polychloroprene adhesives. 

MG rubbers show the hybrid qualities of the blend. When compounded, MG rubbers are self-reinforcing polymers with high hardness, impact resistance, and good elongation. Compatible with natural rubber in all proportions they can be molded into such items as cutting blocks. They also find use in adhesives permitting bonds to be made between natural or synthetic rubbers and PVC, synthetic fibers, leather, etc. 

Chemical structure, concentration, size and distribution of the rubber phase as well as adhesion to the matrix determine processing and final properties, specifically the impact strength. In the case of a powder blend, like PVC/rubber-systems, the characteristic powder data have also to be taken into account. 

Uses Solvent for cellulose acetate, crude rubber, natural resins, nitrocellulose, vinyl resins, waxes, fats, oils, shellac, rubber, DDT, and other pesticides preparation of adipic acid and caprolactum additive in wood stains, paint, PVC paints, lacquers (to prevent blushing or improve flow), and varnish removers degreasing of metals spot remover lube oil additive in PVC adhesives to control evaporation rate leveling agent in dyeing and delustering silk. 

Presently DOE is funding Air Products Chemical Company for the development of a fluorine surface treatment of tire rubber (crumb rubber) to modify its adhesion properties. This modified rubber could be used in making polymers such as polyurethane and epoxies. The tire rubber might also be used in certain plastics such as polystyrene and PVC, and in rubber products (68). 

Plasticizer migration from the vinyl part into the adhesive bond line can degrade the strength of the joint. Adhesives must be tested for their ability to resist the plasticizer. PVC can be made with a variety of plasticizers. An adhesive suitable for a certain flexible PVC formulation may not be compatible with a PVC from another supplier. Nitrile rubber adhesives have been found to be very resistant to plasticizers and are often the preferred adhesive for flexible PVC films. However, certain epoxy adhesive formulations have also been found to provide excellent adhesion to flexible PVC substrates. Several such starting formulations are presented in Table 16.7. A comparison of the performance of several classes of adhesive when bonding PVC to itself and to various other materials is given in Table 16.15. 

Solid dimer polyamides used as vehicles for flexographic inks (14, 24) possess the required alcohol solubility to make it possible to use them on presses with rubber rolls. Their adhesion to films such as polyethylene, Saran, and Mylar is excellent, and their flexibility ensures that they will function properly on these flexible substrates. In addition, they have excellent gloss and good blocking resistance. Thus, they are commonly used on polyolefin, Saran, cellophane. Mylar, cellulose acetate, and PVC films. 

Choice of an appropiate surface treatment and a suitable primer are important because adhesion to the substrates presents difficulties [11.37]. Primers based on modified alkyd resins or two-pack epoxy-resins for derusted ferrous metals mainly contain zinc phosphate and zinc OKide as corrosion protection pigments. Nonferrous metals are first washed with an ammoniacal wetting agent before applying the primer that contains a binder based on synthetic resins (e.g., PVC copolymers, chlorinated rubber) which ensure good adhesion to the substrate. The same primer must be used on zinc or galvanized surfaces because the use of alkyd resins causes embrittlement [11.38] The primed surfaces are largely topcoated with alkyd resin systems. 

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