Patent Application
20080226847
The present invention is related to spatted wood veneers, spatted engineered wood flooring and the method of making the veneers and flooring.
Spalted wood occurs naturally in forests in felled logs and trees which have been infected with spalt fungus (a combination of white rot and blue stain). The spalting makes the wood brittle and difficult to cut into lumber. Therefore, it has not been possible to cut the spalted wood into veneers.
According to the American National Standards Institute, a veneer is a thin sheet of wood, rotary cut, sliced, or sawed from a log, bolt or flitch. A veneer is referred to as a ply when assembled. The formation of spatted veneers would permit the manufacture of spatted engineered wood flooring having a spatted wood veneer decorative layer.
Naturally occurring spalted maple is traditionally used by artisans in lathe produced turnings, e.g. bowls and vases. While spatted solid wood floors have been made from lumber pieces cut from spatted logs, it has not been possible to cut the spalted logs into veneers for use in making engineered wood and engineered wood floors. If the decay progresses too far, the wood becomes punky, soft and spongy, stringy, ringshaked, pitted or crumbly.
Spalting is a decay process in certain wood species that gives the wood a unique blotchy appearance having dark lines. White rot is a decay mechanism that yields thin distinctive lives with broad lighter colored areas in between the lines. White rot is caused by, white rot decay fungi. The white rot attacks the cellulose and lignin giving the wood a whitish appearance and multicolored streaks of black, pink and gray. The white rot spores are typically airborne.
Blue stain does not contribute to the decay of the wood but does yield a yellow, orange, red, blue, black or brown coloration. It is caused by microscopic fungi that infect only the sapwood. The blue stain fungi are normally spread by spores that are carried into the wood by insects.
It is an object of the invention is to provide a spatted wood veneer, particularly a veneer that can be produced in a time frame to enable commercial production.
Another object of the invention is to provide engineered wood flooring, i.e. a multi-layered wood flooring product, having a spatted wood veneer decorative layer.
It is also an object of the invention to provide a method to manufacture a spatted wood veneer.
It is a further object of the present invention to provide a method to manufacture a spalted engineered wood flooring having a spalted wood veneer decorative layer.
To form the spatted veneer, green (wet) wood is cut into veneers and then inoculated with the white rot (e.g. Phanerochaete chyrsosporium) and/or blue stain (e.g. Ceratocystis tenella) spores by coating the surfaces of the veneer with a solution containing the spores. Both of the major surfaces of the veneers can be efficiently coated with a roll coat system. Other means of inoculating the cut veneers is to spray the major surfaces of the veneers with a solution containing the white rot and/or blue stain spores. The environment of the impregnated veneers can be controlled to promote the rapid growth of the spalting and then stopped when the desired degree of spalting is achieved.
The invention is directed to any species of wood which can be cut into veneers and spatted. The wood species that can be used include maple, elm, beech, birch, buckeye, basswood, sycamore, apple, and the hickories. Red oak and white oak will also spalt. While walnut will spalt, it is dark in color and more difficult to observe.
White rot grows best at temperatures of from about 70° F. to about 90° F. and a wood moisture content of about 30% in an oxygen rich atmosphere. The best conditions for blue stain are temperatures between about 60° F. and about 150° F. and a wood moisture content of about 20% to about 30% in an oxygen rich atmosphere. For efficient growth of the white rot and blue stain spores, the wood veneer should have a moisture content of about 20% to about 40% during the spatting process
Therefore, the inoculated veneers can be stacked into a chamber in which a preferred environment for spalting the veneer of about 50° F. to about 100° F. with about 50% RH to about 90% RH is maintained. No growth of the white rot is seen below about 50° F. A more preferred environment for processing the spatted veneers is a temperature of from about 70° F. to about 90° F. and about 70% RH to about 90% RH in an oxygen rich atmosphere.
Prior to loading the inoculated veneers into the chamber, the chamber could be sterilized with an ultraviolet light treatment to kill any other spores. The spalting process may take days, weeks or months, depending upon the type and condition of the wood and the environmental conditions. Samples are removed frequently and inspected to determine when the spalting process should be stopped. It is desired to allow the spalting to proceed to a point where the appearance is pleasing, but the structure of the veneer has not been overly weakened.
The spalting process can be halted by drying the veneers at a temperature of at least 130° F. After the spalting process has been stopped, the spalted veneers can be stabilized and/or stiffened by filling the spatted areas with waxes, oils, glues or impregnation chemicals, such as acrylics. The veneers are then glued to the engineered platform or base, and then tongue and groove edges, including locking tongue and groove edges, are typically machined into the engineered wood piece.
| Number | Date | Country | |
|---|---|---|---|
| 60918605 | Mar 2007 | US |
