Phenolic panels

Fiberboard (fibers with added phenolics) panelling, furniture, insulation... 

Both the published literature and previously unpublished information obtained by the structural panel industry indicate that formaldehyde levels associated with panel products glued with phenol formaldehyde adhesives are extremely low. Large dynamic chamber tests which simulate conditions that might be found in tightly sealed residences indicate consistently that formaldehyde levels associated with freshly manufactured phenolic panel products are less than 0.1 parts per million. The data, as well as theoretical considerations, also indicate that the amount of formaldehyde contributed to the environment by phenolic panel products should rapidly approach zero as the small quantity of formaldehyde initially present in the products is released. 

Because phenolic panels have not presented formaldehyde-related problems in the marketplace, there has not been much need to develop information on formaldehyde emissions from these products. 

Nevertheless, a considerable amount of information has been generated to satisfy curiosity and to answer inquiries concerning emissions from phenolic panel products. This information is summarized in this paper under three primary subject headings (1) Theoretical Considerations (2) Literature Review (3) Previously Unpublished Information. 

A third reason for predicting very low emissions of formaldehyde from phenolic panels is that the cured resin is extremely stable and does not break down to release additional formaldehyde, even under extremely harsh environmental conditions ( ). The high resistance of phenolic resins to deterioration under severe service conditions is, of course, a principal reason they are used so widely in making exterior types of wood panel products. Because of their chemical stability the U.S. Environmental Protection Agency has declared that phenol formaldehyde resins represent a consumptive use of formaldehyde, meaning that formaldehyde is irreversibly consumed in its reaction with phenol so that the formaldehyde loses its chemical identity (3). 

Any formaldehyde that might be present initially in fresh phenolic panels, would be expected to diminish through time, since additional formaldehyde is not released from a breakdown of the resin. Thus, barring contamination from other sources, formaldehyde emissions associated with thoroughly aged phenolic panels should be nil. 

Nestler ( ) thoroughly reviewed the worldwide literature on formaldehyde emissions from wood products published through January, 1977. According to Blomquist ( .)> Nestler s literature review includes only three citations which even mention phenolic adhesives, and none of these citations made specific mention of any problems associated with the use of phenolic panels. 

Since Nestler s review was published, some additional information on formaldehyde emissions from phenolic panels has appeared in the literature. Information obtained using dynamic test chambers is summarized in Table I. Perforator and two-hour desiccator data are summarized in Table II. 

Table I. Summary of Published Dynamic Chamber Test Data for Phenolic Panels...

It is important to note here that higher temperatures probably increase emissions from phenolic panels simply by accelerating the release of that small amount of residual formaldehyde that originates from the adhesive and subsequently becomes adsorbed to the wood substance and water in the wood. Because phenolic resins are very stable chemically, any temperature-related increase in emissions would not be expected to be associated with resin degradation. Consequently, temperature would be expected to exert much less influence on emissions from panels which have been aired out than from fresh panels. Indeed, this trend is shown by the data, as discussed below. 

The two-hour desiccator and Perforator test results shown in Table II are also indicative of very low formaldehyde levels for phenolic panels. As with most of the results obtained in dynamic chamber tests, the uniformity of these test results, both within and between studies, indicates that the various phenolic panel products are quite similar with respect to their emitting potential. 

Much of the information pertaining to formaldehyde emissions from phenolic panels has been obtained by manufacturers of these products but has not been published previously in the open literature. This information has been obtained primarily to form a basis for answering consumer inquiries. 

American Plywood Association Study. Probably the most extensive study of phenolic panel emissions was conducted by W. F. Lehmann of Weyerhaeuser Company for the American Plywood Association. In this... 

Table IV. Results of Large-Scale Dynamic Chamber Tests and Two-Hour Desiccator Tests on Various Types of Phenolic Panel Productsd)...

American Plywood Association study, phenolic panel emissions, 32-35... 

The first known plastic-bodied car was conceived by Henry Ford I as the soybean car . A prototype was produced in 1941, with a tubular steel frame supporting 14 phenolic panels (derived in fact from petroleum, and not soya bean oil). Costs turned out to be far higher than anticipated (the panels were described as only a quarter of an inch thick ). The car is best remembered now for the famous photograph of it resisting a sledgehammer vigorously wielded by Henry Ford (see Fig. 5.1). The Scarab of 1945 was a... 

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