Rubber base

Spirit A 0.675 40- too Rubber-based adhesives cleaning fluids, degreasing fluids... 

Development of Natural Rubber-Based Tmck Tyre Retreading Compounds," in M. E. Cain and Sifi Zubaidah bte Mohd Rashid, eds.. Proceedings of a UNIDO-sponsored Workshop, Kuala Eumpur, Malaysia, Malaysian Rubber Pioduceis Research Association, Heitfoid, U.K, 1992. 

In general the nitroso rubbers also suffer from a poor resistanee to ionising radiation, sensitivity to degradation by organie bases, highly toxic degradation products and an exceptionally high cost. The advent of the rubbers based on perfluorofmethyl vinyl ether) considered above and of the phosphonitrilic elastomers considered below would appear to put the commercial future of these materials in extreme doubt. 

The increased polarity of the acrylic polymers puts more stringent requirements on the properties of the tackifiers or plasticizers that can be used. The very low polarity additives commonly found in rubber based PSAs are not useful in most acrylic PSA formulations. For example, materials like paraffin waxes, mineral oils, and synthetic hydrocarbon tackifiers have little or no value in most acrylic PSAs. 

Rubber base adhesives, also called elastomeric adhesives, are widely used in industrial and household applications. In fact, about one-third of the adhesives used in the World are made from natural or synthetic rubbers. Some of the elastomeric adhesive systems showing industrial importance in recent years are the following ... 

Some rubber base adhesives need vulcanization to produce adequate ultimate strength. The adhesion is mainly due to chemical interactions at the interface. Other rubber base adhesives (contact adhesives) do not necessarily need vulcanization but rather adequate formulation to produce adhesive joints, mainly with porous substrates. In this case, the mechanism of diffusion dominates their adhesion properties. Consequently, the properties of the elastomeric adhesives depend on both the variety of intrinsic properties in natural and synthetic elastomers, and the modifying additives which may be incorporated into the adhesive formulation (tackifiers, reinforcing resins, fillers, plasticizers, curing agents, etc.). 

Structural applications of rubber base adhesives were also obtained using rubber-thermosetting resin blends, which provided high strength and low creep. The most common formulations contain phenolic resins and polychloroprene or nitrile rubber, and always need vulcanization. 

The chemical nature and molecular weight of the rubber will greatly determine the properties of elastomeric adhesives. However, some common characteristics can be found in most of the rubber base adhesives. The elastomeric adhesives show the following specific features in assembly operations. 

Variety of form. Rubber base adhesives can be supplied for assembly operations as solvent or water-borne dispersions, hot melts, precast films, extruded tapes or reinforced films. In addition solvent and water-borne dispersions can be supplied as single or two-components systems. 

Rubber base adhesives develop strength faster than most other polymeric types. Fig. 1 [3J shows the differences in the development of peel strength for several rubber polymers (without additional additives, except an antioxidant). Natural... 

In the next sections, the manufacture, chemistry and properties of the main ingredients of the rubber base adhesives will be considered. 

Several elastomers can be used in rubber base adhesives. The elastomer used is the backbone of the adhesive, so the performance of the adhesive is provided... 

Some properties of elastomers used in rubber base adhesives... 

The elastomers considered in this section have been selected considering the most commonly used in rubber base adhesives natural rubber butyl nibber and polyisobutylenes styrene-butadiene rubber nitrile rubber polychloroprene rubber (neoprene). Typical properties of these rubbers are shown in Table 2. 

Resins used in rubber base adhesive fonnulations have the following characteristics [16] ... 

Rosins and rosin derivatives. The resins more commonly used in rubber base adhesives are rosin esters, particularly glycerol and pentaerythritol esters, as well as rosins modified by disproportionation and hydrogenation. The glycerol ester of hydrogenated rosin has been reported to be an excellent tackifier for polychloroprene adhesives (see pp. 344-357 in [17]). 

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