Neoprene-phenolic adhesives

These alloy adhesives are thermosetting phenolic resins blended with neoprene (polychloroprene) rubber. They are available in solvent solutions in toluene, ketones, or solvent mixtures, or as unsupported or supported films. The supporting medium may be glass or nylon cloth. Neoprene-phenolic adhesive may be used to bond a variety of substrates such as aluminum. 

Neoprene-phenolic adhesives are formulated for room temperature cure and they are used for bonding metal, wood, and many plastics. A combination of neoprene rubber and a / ara-substituted phenolic resin was first described by Thomson. ... 

F. D. Petke (TENNESSEE EASTMAN CO.) I would have thought that an adhesive which resists plasticizers for PVC, such as the acrylic/ phenolic would allow a build-up of plasticizer at the adhesive-adherend interface. How does this behavior agree with your statement that the acrylic/phenolic adhesive has better aging properties on PVC than the neoprene/phenolic adhesive ... 

Temperatures over 300°F and pressure greater than 50 Ib/in are needed for cure. Neoprene-phenolic adhesives are available as solvent solutions and film. During cure, these adhesives are quite sensitive to atmospheric moisture, surface contamination, and other... 

Table 18. A Neoprene/Phenolic Adhesive Test Formulation. ... 

Phenolic Adhesives recommended are neoprene and urethane elastomer, epoxy and modified epoxy, phenolic-polyvinyl butyral, nitrile-phenolic, polyester, cyanoacrylates, polyurethanes, resorcinols, modified acrylics, polyvinyl acetate, and urea-formaldehyde (1). 

The normal service temperatures of these adhesives range from -57°C to 93 °C. Because of their high resistance to creep and most severe environments, neoprene-phenolic joints can withstand prolonged stress. Fatigue and impact strengths are excellent. However, shear strength is lower than that of other modified phenolic adhesives. 

Adhesives recommended include modified epoxies, modified phenoUcs, epoxy-phenolics, neoprene-phenolics, second-generation acrylics, cyanoacrylates, silicone rubbers, and vinyl plastisols. Sell has ranked a number of adhesives in the order of decreasing durability with aluminum adherends as follows ... 

Adhesives recommended include epoxies, polyurethane, silicone, nylon-epoxy, nitrile-phenolic, neoprene-phenolic, acrylic, cyanoacrylate, anaerobics, and partially hydrogenated polybutadiene (for bonding copper to polyethylene). 

Modified phenolics are materials whose resistance to brittle failure has been enhanced by the addition of a more ductile component without fundamentally reducing the good environmental characteristics of the basic phenolic resin. Typical adhesives are based on nitrile phenolics, neoprene phenolics, epoxy phenolics, and vinyl phenolics. Typical service temperatures range from -60 to h-90°C and for phenolic epoxies up to -h250°C. 

Neoprene-phenolic contact adhesives, known for their high green strength and peel values, contain a resole-type resin prepared from 4-t-butylphenol. The alkyl group increases compatibility and reduces cross-linking. This resin reacts or complexes with the metal oxide, eg, MgO, contained in the formulation, and increases the cohesive strength of the adhesive. In fact, the reactivity with MgO is frequently measured to determine the effectiveness of heat-reactive phenolics in the formulation. 

The main reasons for the use of methyl chloroform in formulations for urethane and neoprene/phenolic contact adhesives, mastics, sealants, and natural mbber tire repair cements are its ability to substantially reduce flammability, its non-photochemical reactivity, and the favorable characteristics of the resulting adhesive formulation. 

In this paper we discuss how some of the physical properties of adhesive compositions affect their performance in the areas of contact tack, specific adhesion, and elevated temperature strengths. We concentrate on water-borne acrylic/phenolic systems, but, also draw upon our experience in solvent and water-borne neoprene/phenolic systems. 

Nitrile- phenolic Solvent solutions, unsupported and supported film Heat and pressure Excellent shear strength good peel strength superior to vinyl and neoprene—phenolics good adhesion Metals, plastics, glass, rubber Med... 

Phenolic adhesives, asphalt, neoprene, polyethylene (PE), pol5 ropylene (PP), sodium silicate Glass fiber and rock wool insulation... 

Resins. Because of colloidal incompatibility, the metal oxide/r-butyl phenolic resin complex which in solvent adhesives provides improved adhesion largely and hot strength is ineffective in latex systems. Of the types of resins which are commonly used in Neoprene latex adhesives, only the terpene phenolics such as Durez 12603 (Occidental) and SP-560 (Schenectady) do not cause an appreciable loss in hot strength as the resin content is increased. Others such as coumarone indene resins, liquid terpene resins and rosin esters are valuable from a standpoint of increasing adhesion and open time, but decrease cohesive strength at elevated temperatures. This is illustrated in Fig. 8, where canvas-to-canvas peel strength at 70°C (158°F) is plotted against resin level with several different classes of resins in Neoprene Latex 750. Only the terpene phenolic systems provided adhesive failure, even at the 50 phr... 

Five of the most important two-polymer adhesives used in films and tapes include vinyl-phenolics, epoxy-phenolics, nitrile-phenoUcs, nylon-epoxies, and elastomer-epoxies. Neoprene-phenolics are available in organic solutions and in supported and unsupported... 

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