Natural rubber-based adhesives

De, S.K., Natural rubber-based adhesives. In Pizzi, A. and Mittal, K.L. (Eds.). Handbook of Adhesive Technology. Marcel Dekker, New York, 1994, pp. 315-318. 

M Filament Tape - delamination or separation of the polyester backing from the glass filaments which adhere by means of a natural rubber-based adhesive. 

Use of Solvent-based adhesives in seaming stems from the pioneering work of Charles Macintosh in the last century seam bonding with rubber solutions was a method used in the original waterproof coats carrying his name. Developments of the rubber-bonded seams are used in the manufacture of items such as life jackets and life rafts. The following (in cross-linked form) are commonly used Natural rubber-based adhesives, Poiychioroprene rubber adhesives, Poiyurethane and butyl rubber. 

Further information on rubber-based adhesives is to be found in specialized articles Natural Rubber-Based Adhesives, Nitrile Rubber Adhesives, Polychloroprene Rubber Adhesives Applications and Properties and Polychloroprene Rubber Adhesives Modifiers and Additives. 

Natural rubber-based adhesives JOSE MIGUEL MARTIN-MARTINEZ... 

S. K. De, Natural rubber-based adhesives in Handbook of Adhesive Technology, 2nd edn, K. L. Mittal and A. Pizzi, Eds., Marcel Dekker, 2003, p. 511. 

The chemical structure of CR is analogous to that of natural rubber (see Natural rubber-based adhesives) with the methyl group of cw-l,4-polyisoprene replaced by a chlorine atom, see Fig. 1. 

Natural rubber-based adhesives constitute many nsefnl types of adhesives. They have been made from the latex that is collected from the sap of rubber trees grown in Malaysia and other countries of Sonth East Asia. Rnbber of this type was first collected from the Hevea brasiliensis tree - seeds from the tree were first taken from the Amazon forests in Brazil, propagated in Kew in London, and then supplied, over a century ago, to Malaya and adjacent counuies, where there are now many millions of rubber trees, yielding cis-polyisoprene-based natnral rnbber. This has similar properties to the principal SBR synthetic rubber, derived from styrene and butadiene, both of which are obtained by the cracking process from crnde oil, with subsequent chemical reactions. Natural rubber is obtained from the uee by tapping the bark, when the latex flows out spontaneously as the tree is wounded. This latex is about 33% solids - most natural rubber latex is concentrated to 60% and preserved with ammonia for transport and storage. 

In addition to the articles cited above, further information is to be found in Rubber-based adhesives typical characteristics and Natural rubber-based adhesives. 

Natural rubber (NR) is characterized by high cohesive strength and high tack. For use in solution adhesives, NR must be masticated sufficiently to break down gel and reduce viscosity for dissolution in suitable solvents. When low gel content is achieved, viscosity-stabilized rubbers dissolved without the need for mastication. It is usual to form the rubber into a thin layer to present a large surface to the solvent for rapid swelling (see Natural rubber-based adhesives). 

Natural rubber-based adhesives J M MARTfN MARTINEZ Nature and properties... 

FIGURE 20. Soft-machine curves for a natural-rubber-based adhesive peeling from human skin at three crosshead speeds (mm/min) and four skin temperatures. Circles pertain to 28 C, squares to 32 °C, triangles to 36 °C, and diamonds to 37 X. 

Flat creped papers saturated with rubberlike polymer latices generally have a back-size coating to control the unwind characteristic without impairing the adhesion of paints. In combination with natural-rubber-based adhesives, these tapes are used for masking in the automotive industry, for assembling electronic components, and insulation of low-voltage devices etc. 

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