Neoprene cement

Chemical manufacturing Neoprene cement Rayon selenium... 

One of the first applications in which Neoprene proved satisfactory was in the shoe industry, for both temporary and permanent sole attachment. However, early Neoprene cements were plagued by two problems a decrease in viscosity on aging and a black discoloration during storage in steel drums. 

The stability of Neoprene cements containing metal oxides could be increased with about 10 parts of hydrated calcium silicate, (e.g., Sil-ene EF, PPG Industries) or terpene phenolic resin (e.g., Durez 12603, Occidental Chemical Co.). The presence of the former increased the cohesive strength of Neoprene about threefold, while the latter lowered its cohesive strength at elevated temperatures. 

During World War II, polychloroprene was chosen as a replacement for natural rubber because of its availability. Two copolymers of chloroprene and sulphur which contain thiuram disulphide were available (Neoprene GN and CG). One of the first successful applications of these polychloroprene adhesives was for temporary and permanent sole attachment in the shoe industry. However, these polychloroprene cements show a decrease in viscosity on ageing and a black discolouration appears during storage in steel drums. Discolouration was produced by trace amounts of hydrochloric acid produced by oxidation of polychloroprene... 

Phenolic-neoprene contact cements are used for structural metal-metal bonding. especially where fatigue resistance and low temperature performance are important [209]. They are also used for bonding textiles, wood, rubbers, plastics, ceramics, and glass to metal and to one another. Solvent toxicity and flammability has greatly reduced the use of contact cements in the wood products industry. Water-based contact cements persist, but generally do not perform as well as the solvent systems, thus allowing market erosion by alternative binders. 

There are 16 grades of DuPont neoprene alone. They vary in crystallization rate and potential, viscosity, molecular weight, additive content, and other properties ([216], pp. 284-306). Selection of the right materials requires sophisticated knowledge of both the neoprenes and the phenolic additives. Guggenberger provides a good overview of this situation and some basic formulation information ([216], pp. 284-306). She also provides a prototype formula for a heat-resistant contact cement as shown in the Table 18 ([216], source Table 10, p. 293). 

Heat resistant neoprene-phenolic contact cement... 

Polymeric materials are commonly used for bonding materials. Impact or contact adhesives are mainly based on highly crystalline polychloroprene (Neoprene), NR latex is used as a flexible adhesive very suitable for use with fabrics. Rigid adhesives based on materials such as polystyrene cement, epoxy resin or cyanoacrylates are suitable for bonding of rigid materials. The bond is provided by intramolecular forces between the adhesive and the adherend. Adiabatic... 

Of the remaining materials in Table IV, only Viton, neoprene rubber latex,poly(vinyl alcohol), butyl rubber, and butyl-coated nylon exhibited at least a 20-min breakthrough time forl,2 dichloro-ethane permeation to occur. The nitrile rubber latex, cement dipped nitrile rubber, polyethylene (medium density), and surgical rubber latex were all penetrated by 1,2-dichloroethane in less than 3 min and would be of little use in situations requiring the garment to be in constant contact with 1,2-dichloroethane. From the above, butyl rubber or Viton appear to be the best materials to protect the worker against 1,2-dichloroethane, but because of apparent lot-to-lot variations(20) in butyl properties, Viton appears to be the best suited material of these studies to protect the worker from this chemical. 

A bodied, or more viscous, solvent may be required by certain joint designs and for producing airtight or watertight seals. These are made by dissolving usually 5%-15% of polystyrene by weight in a solvent. Solvent-based contact cements provide the strongest bond between polystyrene and wood. These adhesives all have a neoprene (polychloroprene) base and a ketonic-aromatic solvent system. 

Features Rec. for quick-setting, high-strength adhesive cements offers greater vise, and stability than Neoprene AC Properties Creamy wh. chips or grains vise. 25-115 cps (5% in toluene)... 

Chem. Descrip. Pentaerythritol ester of tall oil rosin CAS 8050-26-8 EINECS/ELINCS 232-479-9 Uses Tackifier for NR, SBR, IR, SBS, hot-melt adhesives, mastic adhesives, contact cements, and pressure-sensitive adhesives in emulsion form used in SBR, natural rubber, and neoprene latex adhesives food pkg, adhesives, coatings, paper, closures with sealing gaskets for food containers defoamer in food-contact paper/paperboard Features High-melting... 

Adhesives used to bond acetal homopolymer to itself and to other materials, such as aluminum, steel, natural rubber, neoprene rubber, and Buna rubber, include polyester with isocyanate curing agent, rubber-based adhesives, phenolics, epoxies, modified epoxies, and vinyls. Solvent cementing... 

Solvent cements are usually preferable to conventional adhesives for thermoplastic structural foams. Some solvent cements and solvent-containing, pressure-sensitive adhesives will collapse thermoplastic foams. Water-based adhesives based on SBR, polyvinyl acetate, or neoprene are frequently used. Solvent cementing is not effective on polyethylene foams because of their inertness. Recommendations for adhesives for thermoplastic foams are ... 

Air leaking Into the lines has given some trouble with airlocking of the pumps. These leaks are covered adequately with neoprene rubber cement. 

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