Polychloroprene rubber adhesives: modifiers and additives

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. 

The curing of CR adhesives is different from that for most rubber-based adhesives as it involves the labile chlorine atoms. This is reflected in the compounding ingredients. The most common room curing agent is zinc oxide, but isocyanates are also very common. Further discussion is given in Polychloroprene rubber adhesives modifiers and additives. 

During the World War II, several new synthetic elastomers were prodnced, and new types of adhesives (mainly styrene-butadiene and acrylonitrile copolymers (see Nitrile rubber adhesives)) were manufactured to produce adequate performance in joints produced with new difficult-to-bond substrates. Furthermore, formulations to work under extreme enviromnental conditions (high temperature, resistance to chemicals, improved resistance to ageing) were obtained using polychloroprene (Neoprene) adhesives (see Polychloroprene rubber adhesives applications and properties and Polychloroprene rubber adhesives modifiers and additives). Most of those adhesives need vnlcanization in order to perform properly. 

Polychloroprene rubber (CR) is the most popular and versatile of the elastomers used in adhesives see Polychloroprene rubber adhesives applications and properties and Polychloroprene rubber adhesives modifiers and additives. 

Polychloroprene rubber adhesives modifiers and additives J M MARXfN MARXfNEZ Resin, tackifier, cross-linking agent addition... 

Prane (11) reviews the field and concentrates on history citing pivotal patents related to acrylics (or reactive ) adhesives. These patents show that numerous materials have been utilized in toughening acrylic adhesivesr some nonreactive in the systems, others reacting in, while still others using combinations of each general type modifier. Thus, we find examples for polychloroprene, thermoplastic urethanes, urethane adducts, acrylic rubber, chlorosulfonated polyethylene in addition to buta-diene/acrylonitrile rubber (or its carboxylic version). 

Standard-grade PSAs are usually made from styrene-butadiene rubber (SBR), natural rubber, or blends thereof in solution. In addition to rubbers, polyacrylates, polymethylacrylates, polyfvinyl ethers), polychloroprene, and polyisobutenes are often components of the system ([198], pp. 25-39). These are often modified with phenolic resins, or resins based on rosin esters, coumarones, or hydrocarbons. Phenolic resins improve temperature resistance, solvent resistance, and cohesive strength of PSA ([196], pp. 276-278). Antioxidants and tackifiers are also essential components. Sometimes the tackifier will be a lower molecular weight component of the high polymer system. The phenolic resins may be standard resoles, alkyl phenolics, or terpene-phenolic systems ([198], pp. 25-39 and 80-81). Pressure-sensitive dispersions are normally comprised of special acrylic ester copolymers with resin modifiers. The high polymer base used determines adhesive and cohesive properties of the PSA. 

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