Contact cement

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... 

The formula in Table 19 is from Guggenberg ([216], source Table 17, p. 305). It is a starting point formula for general-purpose contact cement. The proportions are as dry parts. 

Cements that harden by the loss of solvent generally are to be avoided because the solvent can be lost only be diffusion thru the expl. Diffusion may be slow and the solvent may modify the properties of the expl. Two types of cement that have been used for this purpose are catalytic setting cements, like epoxy resins, and contact cements. Compatibility of the materials to be used should be checked. Compatibility of epoxy resins with most explosives depends upon the catalyst or hardener used (Ref 8). Data regarding bond strengths and other pertinent properties also have been compiled (Refs 5 6)... 

Both surfaces to be cemented should be clean and fit accurately to one another. A minimum continuous layer of cement should be applied to each surface to be joined. Where catalytic resins are used, provision should be made to hold the members in firm contact for the curing period. When contact cements are used, mechanical means are desirable to assure that the elements are in the proper position and orientation when they make the first contact... 

A special-purpose adhesive that forms an exceedingly strong bond to metals and many other materials, including careless experimenters, is cyanoacrylate contact cement, available as Eastman 910 Adhesive and Super Glue (Woodhill Chemical). It is expensive, but only small amounts are needed. In this cement, the material polymerizes rapidly without an added activator. It is not void filling, and a 0.001 in.-thick film yields the best bond. Do not buy more than you will need in a few months since it slowly deteriorates store in the refrigerator. 

This mechanism of adhesion advanced and originally promoted by the Soviets (1963) is of the greatest importance to applications where a material is being adhered to itself, such as in the self tack of rubber. Another familiar example is the application of the same adhesive to two diflerent surfaces from a solvent system, allowing the solvent to dry partially or totally, and then comhining the treated surfaces, such as in the use of contact cement or self-sealing envelopes. 

DispercoII. [Bayer Miles] Polychloro-butadiene and polyurethane latexes for formulation of water-based contact cements, laminating and mastic adhesives for the automotive, construction, furniture, footwear, and iricg. industries. 

Zonester . [Arizona] Rosin esters ther-moplasdc resin, tackifler for rubber, adhesives, contact cements, coatings. 

Contact-Bond Adhesives. Another group of glues, referred to collectively as contact cements or contact-bond adhesives, bear some similarities to the pressure-sensitive adhesives in that they do not rapidly achieve full hardening. Until a few years ago, contact-bond formulations were mainly organic solvent solutions of elastomers, compounded with tackilying resins and antioxidants. However, with recent concerns over energy, environmental, and fire safety questions, interest has turned to water-based systems. 

FIG. 8—Torque versus time data using Brool ield YR-1 Rheometer to test DAP gel formula contact cement. 

The results of the calculations performed on the data for the contact cement and floor adhesive are displayed below in Tables 3 and 4. 

Answer by Author CA-25 contact cement by Minnesota Mining Manufacturing Co. 

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. 

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... 

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