Elastomers, as adhesives

Petrie, E.M., Chapter 10, "Plastics and Elastomers as Adhesives," Handbook of Plastics and Elastomers, edited by C.A. Harper, McGraw-Hill, New York (1975). 

Cement Cements also encompass the use of compounded elastomers as adhesives. They are reviewed solely as solvent dispersions of elastomer compounds. Such cements are generally prepared as needed in the fabrication of a more complicated end item. Typically, conventional elastomer compounding techniques are employed for the solid elastomer and the necessary additives, with the resulting mix blended with appropriate solvents by slow agitation. 

Petrie EM. Plastics and Elastomers as Adhesives. In Harper CA, ed. Handbook of Plastics, Elastomers and Composites. 4th ed. New York, NY McGraw-Hill 2002. 

The largest market for elastomer-based adhesives is that of lamination (see Laminates). Modem office furniture having Formica as a surfacing material is made with an elastomer-based adhesive. Tile adhesives for ceramic or carpet tile are also elastomer-based and usually solvent appHed. Paper adhesives and shoe manufacture also use substantial quantities of mbber-based materials. Solvent-weld adhesives are used to join plastic plumbing and to repair vinyl sheeting. 

As mentioned earlier, the contact-mechanics-based experimental studies of interfacial adhesion primarily include (1) direct measurements of surface and interfacial energies of polymers and self-assembled monolayers (2) quantitative studies on the role of interfacial coupling agents in the adhesion of elastomers (3) adhesion of microparticles on surfaces and (4) adhesion of viscoelastic polymer particles. In these studies, a variety of experimental tools have been employed by different researchers. Each one of these tools offers certain advantages over the others. These experimental studies are reviewed in Section 4. 

Besides the higher volume pressure sensitive adhesives discussed above, the industry also uses other synthetic elastomers as the base component for PSA formulation. Most of these elastomers require some form of tackification to make the materials tacky. However, a few materials are low enough in Tg and sufficiently compliant to be useful without requiring compounding with tackifiers. 

The properties of polymers determine whether they can be used as a plastic, a fiber, an elastomer, an adhesive, or a paint. 

Organic polymers are sometimes referred to as plastics (although, this should be confined to thermoplastic polymers), macromolecules or resins, though the latter is often used to describe raw polymeric material awaiting fabrication. Many polymers are used in various forms that are not associated with normal plastic materials. These include paints and coatings, elastomers (rubbers), adhesives, sealants (caulks), surfactants and also their use in various industrial applications, e.g., ion-exchange resins, membranes. 

The TPEs are often tested with elastomer standards some thermoplastics and TPEs are used as adhesives. Sometimes PE and more rarely PVC are crosslinked. Consequently, the following standards, while mainly concerning thermoplastics and composites, also include adhesives and elastomers. 

Bascom, W.D., Cottington, R.L., Jones, R.L. Peyser, P. (1975). The fracture of epoxy and elastomer modified epoxy polymers in bulk and as adhesives. J. Appl. Polym. Sci. 19 2545-2562. 

Thanks to their multiphase constitution, block copolymers have the originality to add advantageously the properties of their constitutive sequences. These very attractive materials can display novel properties for new technological applications. In this respect, thermoplastic elastomers are demonstrated examples (l, 2, 3) they are currently used without any modification as elastic bands, stair treads, solings in the footwear industry, impact resistance or flexibility improvers for polystyrene, polypropylene and polyethylene whereas significant developments as adhesives and adherends are to be noted (5.). 

THV can be readily bonded to itself and other plastics and elastomers. It does not require surface treatment, such as chemical etch or corona treatment, to attain good adhesion to other polymers, although in some cases tie-layers are necessary. For bonding THV to elastomers an adhesion promoter is compounded to the elastomer substrate.35... 

The species -O-N-R in the scheme is a stable organic radical called a nitroxide, one type of radical that does not react with itself but which reacts with carbon radicals forming weak C-O-N bonds. This approach continues to develop and allows the synthesis of polymers with very narrow molar mass distributions, block copolymers, and polymers with different architectures such as highly branched materials (discussed shortly). This is but one of a limited number of techniques that show promise for producing improved thermoplastics, elastomers, and adhesives for packaging and automotive applications (Anon. 2002). 

Compared to the carboxylated nitrile elastomer additives, the use of thermoplastics has primarily been focused on the aerospace industry. On a cost per pound basis, the two-phase nitrile additives offer the best combination of property improvement without negative impact. The thermoplastic additives, however, may offer better high-temperature performance, but they are more difficult to formulate and to process as adhesives. As a result, the cost of these adhesives is generally much higher than that of other toughened epoxy mechanisms. 

Tiquid rubbers are polymeric products used primarily as adhesives, sealants, castable rubbers, and rocket propellant binders. The name liquid rubber comes from the properties of flowing at room temperature and curing to rubbery networks. These materials offer advantages over conventional elastomers in their ease of handling and processing as they can be readily pumped and mixed in low power (relative to normal rubber) equipment with resultant savings. 

Physical properties such as adhesion to metals tear resistance, abrasion resistance, resistance to diffusion of gas as well as resistance to dilute and concentrated acids, aliphatic and aromatic hydrocarbons, ketones, oil and gasoline, water absorption, oxidation, ozone, sunlight, heat aging, low temperature and flame of the common elastomers are documented in the literature.114 Rating of elastomers with respect to resistance to the factors cited above are in terms of outstanding, excellent, very good, good, fair and poor. 

These surface-anchored layers can be used as adhesion promoters to enhance elastomer-solid adhesive strength. We have shown that there is then an optimum surface density of surface anchored chains to do so. At high coverage of the surface, the layers lose their efficiency, a tendency which can be rationalized in terms of interdigitation between the elastomer and the surface chains. A full characterization of the different regimes of adhesion enhancement associated with the different regimes of interdigitation between the surface chains and the elastomer is a difficult experimental task, not fully accomplished to date. 

Polyurethane formulations cover an extremely wide range of stiffness, hardness, and densities. The performance properties of polyurethane can be widely modified by selecting appropriate raw materials, catalysts and auxiliary compounds, by employing various production methods and/or by employing various methods for further processing and/or for shaping the final products. Therefore, polyurethanes have wide applications such as elastomer, coating, adhesive, foam, and leather. 

Applications. PBCMO is used especially as material resistant in corrosive atmospheres at moderately elevated temperatures. Useful applications are found as adhesives, coatings, sheeting, lining pipes, tanks, etc. It must also be noted that BCMO and other oxetanes are also used to prepare polyglycols which are used in polyurethanes, polyesters, and polyamide-type elastomers. 

---