Résumé : |
Rubber covered rolls, or rollers, are used to handle a variety of materials in business and industry. Depending on the application, rollers may be exposed to high pressure, heat and potentially damaging fluids such as caustics, acids and solvents. The durability of the bond between the roller core and the rubber covering is critical to performance of the roller.
Manufacturers of rubber covered rolls have a long history of succesful use of solvent-borne rubber to metal (R/M) adhesives. Passage of the U. S. Clean Air Act Amendments (CAAA) in 1990, however, has had a significant impact on the future use of these adhesives. Title I of the CAAA requires that emissions of volatile organic compounds (VOCs) be reduced. Typical R/M adhesive contain as much as 6.0 to 7.0 lb VOC per gal. Decreasing the amount of solvent is not a viable option because of consequent difficulties in adhesive application. VOC-exempt solvents, such as 1,1,1-trichloroethane, will soon be banned from production due to their ozone depleting potential.
In addition to Title I regulations, many traditional R/M adhesives contain solvents considered hazardous air pollutants (HAPs) under Title III of the Clean Air Act. Emissions of these substances lust be controlled through the use of "maximum achievable control technology". This includes emission control equipment such as incinerators or carbon absorbers, but can also include the use of compliant adhesives that contain no HAPs.
Given the current regulatory climate, development options for R/M adhesive formulators are limited to 100% solids or aqueous systems. |