Radio-frequency drying of latex adhesive on carpet. Final report
- Georgia Inst. of Technology, Atlanta, GA (United States). School of Textile and Fiber Engineering
Approximately half of the world`s carpet production is in the United States. During the tufting of carpet, face yarns are inserted through the primary backing, but are not locked in. Secondary lamination with a latex adhesive (backcoating) anchors the tufts, adheres to the secondary backing and provides dimensional stability. Unbacked carpet is pulled through an applicator that applies a layer of latex adhesive to the back side of the carpet. The coated carpet is then laminated to the secondary backing (which has a thin layer adhesive applied to it) and transported by a tenter frame through a convection oven for drying and curing the latex adhesive. Laboratory drying tests were conducted with convection and rf ovens to simulate production conditions and provide a baseline for evaluating the effects of rf heating on drying and curing two typical qualities of carpet (23 and 32 oz/sq yd). With rf preheating the latex temperature increased to 100{degrees}C in less than 20 seconds while it took more than 300 seconds for convective heating. Rf preheating was also found to significantly increase the subsequent drying rate in the convection oven. Since the convective drying rate does not appreciably decrease until the target moisture content of 5% is reached and benefits of preheating are lost when the rf oven follows the convection oven, rf postheating does not offer the advantages of rf preheating. Conclusions are: (1) The component primarily responsible for rf heating of latex-backed carpet is water. (2) Rf preheating and rf postheating are technically feasible. Both reduce moisture content in latex-backed carpet without affecting product quality. (3) Rf preheating has more potential than rf postheating since it eliminates the heating time to reach the maximum drying rate associated with convective drying. (4) Retrofitting an existing backcoating line with a 330-kW rf preheating oven could increase production from 50 fpm to 100 fpm with a simple payback of 1.4 years.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Georgia Inst. of Tech., Atlanta, GA (United States). School of Textile and Fiber Engineering
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 10191354
- Report Number(s):
- EPRI-TR-102546; ON: UN94001883; TRN: 93:003931
- Resource Relation:
- Other Information: PBD: Aug 1993
- Country of Publication:
- United States
- Language:
- English
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