NYS Governor's Awards for Pollution Prevention - Emsig
Emsig Manufacturing Corporation, Hudson
Emsig is a manufacturer of clothing buttons employing 150 people in Hudson. Buttons are made from unsaturated polyester resin that requires one of two casting processes or a molding operation. In all these processes the containers, tools and equipment used to work with the resin were previously cleaned with acetone. Emsig switched to a non-toxic, non-hazardous cleaner called Cleaner No. 10 and a closed-loop ultra-filtration system that recovered 90 percent or better of the new cleaner.
Methodologies and Procedures
Plastics buttons are made in one of two casting processes or molded. In the first casting process, sheet casting, pigments are added to the resin to create the desired colors. Catalyst and promoter are added to harden the material which is then poured into large rotating drums through a pour can which determines the button pattern. When the material reaches a solid state it is removed from the drum as a sheet from which button blanks are punched. The blank is then cured to final hardness.
In the second casting process, rod casting, the resin is prepared as in the sheet casting process. The resin is then pumped to a machine which controls the flow of the different colors down a trough creating the desired pattern. The resin is caught in an aluminum tube of varying diameter depending on button size and is hardened. When it reaches a solid state, it is pushed out of the tube and sliced into button blanks.
In the molding process, the resin is first cooked to increase its viscosity and reactivity. It is then laid up in a layer of PVA film, tissue, and cardboard. This is then placed into a molding press which forms the button blanks.
In all these processes, the containers, tools, and equipment used to work with the resin were cleaned with acetone because of its ability to easily remove and dissolve the polyester resin.
In 1993, Emsig decided to reduce the generation of acetone 95 percent by substituting it with an aqueous cleaner, Cleaner No.10. Aqueous cleaner emulsifies rather than dissolves resins. Because of this, resins will drop out of solution, settle and then harden, plugging piping and pumps. If the cleaner is continually circulated, less resin settles out, but the cleaner quickly becomes saturated and no longer will clean the part. The waste from this process cannot be discharged to a sewer due to the styrene content and disposal costs would be excessive.
The solution to the excessive cleaner cost and waste disposal was the use of a closed-loop ultra-filtration system. Testing with the equipment showed an average recovery of 68 percent, and once in a closed-loop system, recovery could reach 90 percent or better. The ultra-filter separates the resin form the cleaner which is then hardened and disposed of in a landfill. The cleaner is continually reused adding only enough fresh cleaner to make up for the losses.
In the eight months that the system was in operation in 1995, the need for 140,087 pounds of acetone was eliminated. The total raw material and disposal cost savings for acetone was $105,748.
During the same period, 30,600 pounds of Cleaner No.10 were used at a cost of $20,700 resulting in an overall savings of $85,048.
Annual savings for material and disposal costs for 1996 over 1994 usage were estimated at $133,000.
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This page was last modified March 8, 1999