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Finding new ways to make adhesives for high-speed packaging applications.

The CCPA's Responsible Care program provided the impetus for Nacan to study different adhesives formulations

Until recently, the formulations of many adhesives included what are now considered by some to be potentially hazardous chemicals. For example, solvents were heavily relied on for high-speed packaging applications.

As long as the adhesives did the job and were competitive in cost, questions of chemical exposure or the effects of solvents flashing off into the atmosphere were not an issue.

However, that changed in the mid-1970s as awareness of the risks involved with chlorinated solvents became a growing public concern on an international scale. The development of super sensitive scientific measurement techniques added to the pressure that manufacturers and end users faced to rethink their processes and applications.

The chemical industry spearheaded a North American initiative to formalize conduct in the making and handling of chemical products. Manufacturers acknowledged that the responsibility for safety was theirs.

This led to the Canadian Chemical Producers Association (CCPA) program of Responsible Care. In 1985, formal signature to this set of principles was made a condition of CCPA membership.

As a CCPA member, Nacan Products Ltd. accepted the program and implemented its requirements throughout its operations -- R&D, manufacturing, transportation and distribution, hazardous waste management.

However, it is one thing to say that certain chemicals must not be used, but quite another to find a way of achieving the same results as a comparable cost using different chemicals.

Nacan decided that if there were concerns about the safety of a substance it was using, the substance would not be used again and a replacement or new approach would be developed. This philosophy extended to clients, that they might also have to modify their production methods.

Nacan's technical manager, Jim Northover, said that one of the more significant opportunities is the potential to switch from solvent-borne adhesives to water-borne formulations. The volatile organic content (VOC) -- MEK, toluene, ethyl acetate, hydrocarbons -- of conventional adhesives is considered a major polluter because the solvent was flashed off in the drying process and voided to the atmosphere. Solvents contained in the waste were also likely to end up in plant effluent.

Nacan can now offer water-borne adhesives for virtually all packaging applications, as well as water-borne cements and laminating adhesives. Solvent contact cements can be replaced by neoprene latex adhesives. Solvent-borne urethanes can be replaced by acrylic emulsions.

Nacan can also offer 100%-solids content urethanes and epoxies to replace solvent-borne systems. Water-borne and hot melt pressure sensitive adhesives can replace some solution grades. For example, solvent-borne rubber solutions can be replaced by synthetic rubber hot melt adhesives and acrylic or synthetic rubber emulsions.

The water-borne adhesives have been successful in achieving acceptable performance levels on the production line and in the field while remaining cost-competitive. Northover noted that there has been "no holus-bolus change from solvent- to water-borne adhesives although they are available."

The owner of Multi-Tac Inc., Frank Filipelli, started the company as a water-based operation. "Solvent-based adhesives are less than 32% solids whereas water-borne are in excess of 55% solids. And water needs to be driven out because it doesn't flash off like a solvent. So you have to make some adjustment to your air velocity and drying temperature, but that's about it."

Not only water-borne adhesives, but others that contain no potentially questionable substances are finding wide commercial acceptance. As Northover explained, "With each new concern we evaluated our materials list and if we used it, we sought out a way to eliminate it."

Nacan goes as far as auditing customer operations to evaluate health and safety procedures in the handling and application of its adhesive products. Its policy is to not sell to companies which do not handle products safely or responsibly. This is part of the Responsible Care philosophy.

Product development is a joint venture between Nacan and its customers. Canadian Coated Papers -- Labelmasters produces pressure sensitive label materials using 100%-solids adhesives. Production manager John Melo said, "We have no solvents and no effluents in our process."

The company is working with Nacan to reformulate adhesives to achieve the desired results. "We are now seeking properties that are not available in a hot melt today," Melo added. This has a double benefit: to the customer which gets what it wants and to the supplier for finding out what the market needs.

Nacan is working with major packagers and paper and board mills to satisfy the need for hot melts and liquid adhesives that do not interfere with the repulping process. Nacan's Cycloflex and Cyclobond formulations have met the needs of some mills and packagers, but more work is needed to define the repulping requirements of all mills involved in recycling waste packaging.
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Publication:Canadian Chemical News
Date:Jan 1, 1993
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