Adhesives, neoprene

During World War II, several new synthetic elastomers were produced and new types of adhesives (mainly styrene-butadiene and acrylonitrile copolymers) were manufactured to produce adequate performance in joints produced with new difficult-to-bond substrates. Furthermore, formulations to work under extreme environmental conditions (high temperature, resistance to chemicals, improved resistance to ageing) were obtained using polychloroprene (Neoprene) adhesives. Most of those adhesives need vulcanization to perform properly. 

Ncoweld. [Itiperial Adhesives] Neoprene adhesive latex. 

Choice of adhesive. Use neoprene adhesive for applications where vibration, bumps, etc., are encountered such as over-the-road trailers. For higher temperatures epoxy is preferred. Neoprene-based adhesive should be allowed to dry to touch before the sheets are applied over it. Neoprene adhesive is used for application temperature not exceeding 107°C while epoxy adhesive is used for up to 121°C. It is important to note that adhesive can become a weak link in an otherwise strong chain. 

Solvent-based neoprene adhesives develop qmck initial bonds and remain strong and flexible most indefinitely. They can be used to join a wide variety... 

Buchoff, L.S., Adhesives in the electrical industry (Chapter 50). Handbook of Adhesives (I. Skeist, ed.), 3rd ed.. Van Nostrand Reinhold, New York, 1990. Steinflnk, M., Neoprene adhesives solvent and latex (Chapter 21). Handbook of Adhesives (I. Skeist, ed.), 3rd ed.. Van Nostrand Reinhold, New York, 1990. 

PTBP had been known to cause contact dermatitis in shoe manufacturers, and wearers, and in automobile assemblymen (Kahn 1970). PTBP formaldehyde resin (PTBPFR) is also a contact sensitizer, present in neoprene adhesives used in the manufacture of car seats, roof linings, and care interiors. Depigmentation on the hands and forearms were observed in 11 of 99 British automobile factory workers who were exposed to a PTBFR glue without wearing protective gloves (Calnan and Cooke 1974). Malten (1984) attributed the leukoderma to excess PTBP in the glue. 

Diphenylmethane-4,4 -diisocyanate, 1% petrolatum. In urethane or neoprene adhesives Toluene-2,4-diisocyanate, 1% petrolatum. In urethane or neoprene adhesives... 

Then the width of the stream depends on the type of adhesive low viscosity water-based adhesives will give a 50 cm width while rubber-based adhesives, such as neoprene adhesives, may give oidy 30 to 45 cm width. It also depends on the viscosity the more fluid the adhesive, the easier it will be to spray it in fine particles. 

Only the water based adhesives and glues such as vinyls, acrylics, some thermosetting glues such as UF, some fluid epoxies may be sprayed with airless spray. However, we may mention here the use of airless to spray a dispersion contact neoprene adhesive of high viscosity - 50,000 mPas - with a coverage of 100 g/m. ... 

Polyurethane and CR adhesives are widely used for bonding vulcanised rubber. Urethane adhesives perform better in some respects compared to neoprene adhesives on greasy leather as excessive grease and fatty acid present can affect neoprene adhesives more adversely [35]. Vulcanised SBR can be bonded satisfactorily using neoprene adhesive if the surface is freshly prepared. Urethane adhesives used are of three types ... 

The data of Table 2 indicates that water-borne acrylic/BKUA-2260 adhesives have excellent metal adhesion whereas water-borne acrylic/ CK-1834 dispersion adhesives and water-borne neoprene adhesives have poor metal adhesion. The dispersing aids employed in the last two systems were investigated as possible causes of this lower metal adhesion. The surfactant system employed to disperse CK-1834 and similar phenolics is listed at the bottom of Table 7. In order to separate out the effects of the dispersing agents and at the same time maintain a stable system, the CK-1834 phenolic and the acrylic resin were put into acetone solution. The components of the dispersant system were individually added and their effect on the metal adhesion of the system was determined. The data of Table 5 clearly shows that the oleic acid and its salts are the principle cause of the reduced metal adhesion The peel strengths fall off dramatically when these components are added. Furthermore, the dark violet color, characteristic of the phenolic-iron complex, disappears, indicating that the oleic acid interferes with the phenolic substrate interaction and forms a weak boundary layer. 

The ability of Neoprene adhesives to crystallize sets them apart from other elastomeric binders. As a result of crystallization, their cohesive film strength is much greater than that of amorphous polymers. Crystallization is a reversible phenomenon, and at temperatures over... 

Metal oxides serve several functions in Neoprene adhesives as shown below ... 

Neoprene adhesives containing metal oxides and r-butyl phenolic resins may separate on standing into a clear upper layer and a lower layer of flocculated metal oxides. This separation, called phasing, may occur in days or months. Once an adhesive has phased, it must be agitated before use to obtain full utility of the metal oxides. 

Terpene phenolic resins, such as Schenectady s SP-560 or Occidental s Durez 12603, are also often used in Neoprene adhesives. They are nonreactive and thermoplastic in nature and so provide longer open tack time and a softer glue line than the f-butyl phenolics, but offer less hot cohesive strength. Terpene phenolic resins are often used in combination with a polyisocyanate curing agent, such as Bayer s Desmodur RF, in a two-part adhesive system to obtain better hot bond strength. 

Fillers find limited use in Neoprene adhesives. They are included primarily to reduce cost in high solids mastics. Conventional fillers such as clay and calcium carbonate are used effectively at levels as high as 250 phr in some mastic applications. 

The procedures used to prepare Neoprene adhesive cements can affect end use properties such as hot cohesive strength and spray ability. Techniques used to prepare cements include milling, direct dissolving, and direct dissolving... 

Automotive uses for Neoprene adhesives also go back many years and include such things as adhering sponge insulation strips to doors and trunk and hood lids. Other applications include attachment of vinyl trim in panels and adhering vinyl landau tops to roofs. Traditional Neo-prene/resin contact cements are used to bond plasticized PVC in these applications because the required adhesion level is not as great as in the shoe industry and/or a barrier film is employed. 

Neoprene adhesives are conventionally applied by spraying, curtain coating, roller coating, brushing, or extrusion (i.e., by a caulking gun). Spraying is by far the most important industrial technique, as it permits rapid laydown of ad-... 

McDonald, J.W., Neoprene Adhesive Processing-High Shear Refining, DuPont Elastomers Informal Bulletin. 

Trim adhesives - Neoprene adhesives are used to adhere vinyl trim and tops as well as in laminating plastie to wood and steel. Nonvulcanizing natural rubber... 

The proportions of these configurations determines the reactivity to vulcanization (1, 2 addition) and the amount of crystallization (trans-1, 4). Neoprene is more e q)ensive than natural rubber or SBR but it is used more frequently for several reasons. Neoprene adhesives based on polymers with high trans-1,4, content crystallize quickly giving high bond strengths. 

Neoprene adhesives show excellent resistance to attack by oils, solvents, water, acids, chemicals, heat, and weaflrering. There are many grades of Neoprene polymer available for use in bodi solvent based and latex adhesives. Neoprene adhesives, because of dieir high bond strengths, are used in the manufacture of shoes (gluing soles), for adhering automobile vinyl trim and tops, and in laminating plastic to wood and steel. 

Statt, B.K. et al, 1992, "Precipitated Silicas in Adhesives and Sealants", Supplier Short Course on Additives, Adhesive and Sealant Council, Washington, DC, April, pp IV, 1-30. Steinfmk, M., 1977, "Neoprene Adhesives Solvent and Latex", Handbook of Adhesives, 2nd ed., 1. Skeist(ed.), Van Nostrand Reinhold, New York, pp 343-367. 

Steinfink M. Neoprene adhesives solvent and latex (chapter 21). In Skeist I, ed. Handbook of Adhesives, 3rd ed. New York, NY Van Nostrand Reinhold 1990. 

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