Nitrile mbber adhesive

Nitrile latices are used ia a wide variety of appHcations, including production of dipped nitrile mbber products. In the principle use of paper saturation, adhesives and fiber bonding, small particle size and optimum surface tension is desirable to achieve rapid penetration and setup or dryiag. 

Adhesion. Commercially available 1- or 2-coat adhesive systems produce mbber failure in bonds between ethylene—acryflc elastomer and metal (14). Adhesion to nylon, polyester, or aramid fiber cord or fabric is greatest when the cord or fabric have been treated with carboxylated nitrile mbber latex. 

Adhesion of melamine fiber to rubber matrices Rajeev et al. found that the dry bonding system consisting of resorcinol, hexamethylene tetramine and hydrated silica effectively reinforces EPDM [64], maleated EPDM [118], and nitrile mbber matrices [119]. They observed increase in tensile... 

NR, styrene-butadiene mbber (SBR), polybutadiene rubber, nitrile mbber, acrylic copolymer, ethylene-vinyl acetate (EVA) copolymer, and A-B-A type block copolymer with conjugated dienes have been used to prepare pressure-sensitive adhesives by EB radiation [116-126]. It is not necessary to heat up the sample to join the elastomeric joints. This has only been possible due to cross-linking procedure by EB irradiation [127]. Polyfunctional acrylates, tackifier resin, and other additives have also been used to improve adhesive properties. Sasaki et al. [128] have studied the EB radiation-curable pressure-sensitive adhesives from dimer acid-based polyester urethane diacrylate with various methacrylate monomers. Acrylamide has been polymerized in the intercalation space of montmorillonite using an EB. The polymerization condition has been studied using a statistical method. The product shows a good water adsorption and retention capacity [129]. 

Uses Plasticizer, softener for NR, SR, nitrile mbber, CR, vinyl, film sheeting, textile coatings, pkg. materials, adhesives, nitrocellulose films Features Monomeric does not affect cure gives vulcanizate with extremely good aging and elec, props. gives low temp, flexibility Properties APHA 35 m.w. 390 sp.gr. 0.985 dens. 8.2 Ib/gal vise. 375 cSt (0 C) pour pt. -60 E cloud pt. < -60 E flash pt. 420 E ref. index 1.4851... 

Nitrile rubber adhesives have been used to bond medium-to-high polarity rubbers with polyamide substrates. In an early work, nitrile rubber in solvent was treated with 10-20 parts of phosphoric acid at 50-100°C and subsequently neutralized. In more recent work, acrylic acid, methacrylic acid, dicumyl peroxide and phenol ether were added to a mixture of nitrile and formaldehyde-phenol oligomer to give a mbber-to-polyamide adhesive. 

This is one of the most important synthetic thermoplastic elastomers. Nitrile mbber is a copolymer of butadiene and acrylonitrile. The copolymer usually contains enough acrylonitrile (>25%) so that good resistance to oil and grease can be obtained. Adhesive properties also increase with increasing nitrile content. These adhesives are used to bond vinyls, other elastomers, and fabrics where good wear, oil, and water resistance are important. Compatibility with additives, fillers, and other resins is another advantage of this material [3,80]. Table 5.7 summarizes the properties of nitrile rubber. 

Adhesives recommended are epoxies, phenolic-polyvinyl butyral, epoxy-phenolic, nitrile-phenolic, polyurethane, neoprene, butadiene-nitrile mbber, cyanoacrylates, resorcinol-polyvinyl butyral, furane, and urea-formaldehyde. 

Adhesives. Contact adhesives are blends of mbber, phenoHc resin, and additives suppHed in solvent or aqueous dispersion form they are typically appHed to both surfaces to be joined (80). Evaporation of the solvent leaves an adhesive film that forms a strong, peel-resistant bond. Contact adhesives are used widely in the furniture and constmction industries and also in the automotive and footwear industries. The phenoHc resins promote adhesion and act as tackifiers, usually at a concentration of 20—40%. In solvent-based contact adhesives, neoprene is preferred, whereas nitrile is used in specialty appHcations. The type and grade of phenoHc resin selected control tack time, bond strength, and durabiHty. 

The most common adhesive system used for bonding continuous fibers and fabrics to rubber is resorcinol-formaldehyde latex (RFL) system. In general, RFL system is a water-based material. Different lattices including nitrile and SBR are used as the latex for the adhesive system. 2-Vinylpyridine-butadiene-styrene is the common latex used in the adhesive recipe. RFL system is widely being used in tires, diaphragms, power transmission belts, hoses, and conveyor belts because of its dynamic properties, adhesion, heat resistance, and the capacity to bond a wide range of fabrics and mbbers. 

These materials are based on polymer latexes made by emulsion polymerization. They flow easily while the continuous water phase is present and dry by evaporation of the water, leaving behind a layer of polymer. In order that the polymer particles coalesce to form a continuous joint and be able to flow to contact the adherend surfaces, the polymers used must be above their glass transition temperature at use temperature. These requirements are similar to those for latex paints, so it is not surprising that some of the same polymers are used in both applications, for example, styrene-butadiene copolymers and poly(vinyl acetate). Nitrile and neoprene mbbers are used for increased polarity. A familiar example of a latex adhesive is white glue, basically a plasticized poly(vinyl acetate) latex. Latex adhesives have displaced solvent-based adhesives in many applications because of their reduced pollution and fire hazards. They are used extensively for bonding pile and backing in carpets. 

Styrene Block Copolymer Cheap Good heat resistance Good toughness Low water absorption Poor adhesion to nitrile, neoprene, natural mbber... 

Suggested adhesives include modified acrylics, epoxies, polyesters, resorcinol-formaldehyde, fiirane, phenol-formaldehyde, polyvinyl formal-phenolic, polyvinyl butyral, nitrile rubber-phenolic, polyisobutylene mbber, polyurethane rubber, reclaimed rubber, melamine-formaldehyde, epoxy-phenolic, and cyanoacrylates. For maximum adhesion primers should be used. Nitrile-phenolics give excellent bonds if cured under pressure at temperatures of 149°C. Lower-strength bonds are obtained with most mbber-based adhesives. 

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