While any Neoprene polychloroprene grade can be used to make a solvent-based adhesive, the A grades and W grades are preferred. The two main criteria which influence the polymer selection when designing an adhesive formula are the crystallization rate and viscosity. Crystallization determines the rate of initial strength development. The faster the rate of crystallation, the faster the rate of strength development.

Viscosity influences the inherent strength of the adhesive film, the solution viscosity and solids content. The higher the polymer viscosity or molecular weight, the higher the film strength, the higher the adhesive viscosity, or the lower the solids at a given adhesive viscosity.

Dipped Goods

Elastomeric parts are made by a variety of techniques: injection and compression molding, continuous extrusion, and hand built-up. All of these use dry rubber manufacturing techniques. Parts are also made by a liquid process called dipping. In this technique, raw liquid dispersions are first compounded with the proper formulating ingredients. The liquid compound is placed in a tank into which forms, typically porcelain, are lowered and held while the liquid dispersions compound slowly builds thickness on the form. The form is then withdrawn yielding a uniform coating of rubber composition. After drying and curing, the part is stripped off of the form for finishing operations.

The main application for this process is the production of thin wall parts where molding would be difficult to control. Examples are supported and unsupported gloves, convoluted boots, weather and toy balloons, play balls, metal and fiber coatings, and related industrial and consumer applications. Neoprene liquid dispersions are well suited to this manufacturing process due to the high initial strength of the deposited film combined with its well known balance of final properties, including heat and ozone resistance, weatherablity, oil and chemical resistance, and tear strength.

Neoprene liquid dispersions must be compounded to achieve best results.

Binders, Coatings and Modifiers

Neoprene liquid dispersions are used in a variety of applications where its resistance to heat, oil, chemicals, ozone, weathering, and its good mechanical properties enable products to be made with superior performance properties. Examples include:

• Wet-end and saturated paper
• Bonded fibers
• Coated fabric
• Industrial coatings
• Elasticized concrete
• Modified asphalt
• Carpet backing

While it is the key component of the compositions used for the above applications, Neoprene must be formulated to bring out its performance features.