INTRODUCTION
Middlebury Hardwood Products, Inc. initiated a joint project with the Indiana Pollution Prevention and Safe Materials Institute (IPPI) to investigate measures the company could take to reduce emissions of volatile organic compounds (VOCs). The investigation centered around the wood finishing operation, which is responsible for nearly all of the VOCs emitted by the company.
COMPANY BACKGROUND
Middlebury Hardwood Products, Inc. is located in Middlebury, Indiana, and produces high quality hardwood cabinet doors and drawer fronts for the factory-built home industry as well as for the recreational vehicle industry. The company employs approximately 150 people.
MANUFACTURING PROCESS
The company purchases rough-sawn, hardwood lumber, which it machines, molds, and constructs into doors and drawer fronts. The material is then sent to the wood finishing department where a three-step, finish coating process begins. The parts receive an automated finish sanding just prior to the stain application process. The stain dries rapidly, and the parts receive a sealer coat, which is allowed to flash dry for ten minutes. The sealer coat is then scuff-sanded using an automated fladder sander. The parts are then coated with the finish topcoat and allowed to flash-dry for approximately ten minutes. The parts are then fed to a batch oven which operates at 140( F for eleven minutes. The parts are removed from the oven, allowed to cool, and are immediately inspected and stacked for finished-goods inventory.
P2 PROJECT
Middlebury Hardwood Products and IPPI formed a team to investigate areas in which VOC and HAP (hazardous air pollutants) emission reductions could be accomplished. The team decided to take a novel approach and invited four wood finishing coating manufacturing companies to come to the plant and perform a full-production, trial run.
Each coating manufacturer was challenged to develop a three-part coating system tailored specifically for Middlebury Hardwood Products' high-output production schedule. The team's criteria for the coating manufacturers to meet was as follows:
Middlebury tested the coatings of the four coating manufacturers over a two-day period in a full-production atmosphere on its production finishing line. The overall results of the two-day trial demonstrated the following:
Overall, the Middlebury Hardwood Products/IPPI team estimated that VOC reductions approaching 55% could be achieved.
POTENTIAL ENVIRONMENTAL AND COST BENEFITS
The team found that due to the higher-solids content of the four candidate coatings, the surface coating rate of the products was nearly double that of the low-solids finish products the company currently uses. This indicated that nearly twice as many doors and drawers could be coated (per gallon) using the higher-solids candidates, as opposed to the lower-solids counterpart. The cost, per gallon, of the new higher-solids candidates ranged from 20-30% more expensive than the low-solids coating system. However, while the high-solids coating materials cost more per gallon, the coverage rate was double that of the low-solids coating system. Consequently, the new higher-solids coating system candidates offered an estimated cost reduction to the company of 22 to 35%. Overall, initial estimates suggest that the new high-solids systems could reduce VOC emissions by over 50% (nearly 90 tons) and also achieve potential cost reductions in excess of $100,000.
CONCLUSION
The Middlebury Hardwood /IPPI team decided that the two best performing high-solids, finish coating manufacturers should be requested to return for a full production test lasting, approximately, two weeks. This two-week test period will give the company time to estimate, with a greater degree of accuracy, the true VOC reduction and potential cost savings derived from utilizing the new, high-solids coatings. Additionally, the company will be able to gauge more accurately the new candidates performance with regard to quality and processing characteristics during the demanding, high-output, finish line production schedule.
Middlebury Hardwood has invested a great deal of time, effort, and money into investigating the best method to reduce VOC emissions. Their commitment to this task sets them apart from others in their industry and confirms their reputation as a company which takes the lead in all its endeavors.