Patent Application
20190351574
There are several methods of treating wood to improve the properties and characteristics thereof for any given application. One such method is thermal-modification, also referred to as thermo-curing, thermo modification, baking, roasting, thermal-stabilization, among other names. Thermal-modification is accomplished through various methods, including hot oil treatment, steam treatment, and pressurized nitrogen-atmosphere treatment. All thermal modification methods involve heating the wood to varied temperatures that may range from 160° C. to 190° C. Time frames for full thermal modification vary, depending upon the treatment applied. While most methods can be complete within 72 hours, some methods involve a curing, drying, and conditioning process that can last seven days. Every method of thermal modification causes a pyrolytic transformation in the chemical structure of lignin, cellulose, and hemicellulose components of the wood. Although thermal-modification of wood often leaves many wood species more rigid and durable, the treatment also makes many species less flexible and often brittle.
Another method of treatment is the impregnation of wood with various treatment agents. Impregnating wood with various treatment agents can improve the wood's properties such as strength, durability, water resistance, dimensional stability, resistance to degradation, and fire resistance. A conventional method of impregnating wood involves immersing the wood in one or more treatment agents and applying pressure to force the treatment agents into the wood. This typically occurs in a large container such as an autoclave. Other passive impregnation methods are also known in the art including spraying, diffusion, and soaking the wood in one or more treatment agents without the application of pressure. The penetration of the treatment agent into the wood is therefore directly dependent on the exposure time of the treatment agent and/or the amount of pressure applied. The penetration may further be improved by heating the wood and treatment agent during impregnation. However, such techniques of using pressure, heat, or a combination thereof may cause the wood to distort, warp, shrink, or otherwise deform from its original shape. In addition, wood impregnation currently takes place on a large scale to impregnate as much wood as possible for a given impregnation cycle. This requires large processing facilities utilizing monstrously sized autoclaves, which may increase operating costs, increase costs to the consumer, and reduce the number of potential suppliers.
Further, these impregnation techniques have not been applied to dimensionally formed, thermally modified wooden products (e.g., wood formed/constructed into a final end-user product or a constituent thereof). Otherwise, such a method may be advantageous to produce a readily available wooden product having superior properties and/or characteristics. Such a method may further reduce overall manufacturing costs, specialize the impregnation process for a given wood species or wooden product, and/or streamline production for companies that manufacture wooden products.
Thus, there exists a need in the art for a method of producing a thermally modified and impregnated wooden product that has been dimensionally pre-formed prior to impregnation and resists deformation during impregnation.
The present invention generally relates to methods of treating wood, and more particularly, to a method of producing a thermally modified and impregnated wooden product.
The general purpose of the method of producing a thermally modified and impregnated wooden product, described subsequently in greater detail, is to provide a method of producing a thermally modified and impregnated wooden product which has many novel features that result in a method of producing a thermally modified and impregnated wooden product which is not anticipated, rendered obvious, suggested, or even implied by prior art, either alone or in combination thereof.
A method of producing a thermally modified and impregnated wooden product is provided herein. In a particular embodiment of the method, a pre-formed thermally modified wooden object is impregnated with one or more treatment agents to produce the thermally modified and impregnated wooden product. The impregnation may include the application of pressure and heat to the thermally modified wooden object while the object is in the presence of one or more treatment agents. The impregnation may include the application of pressure to the thermally modified wooden object while the object is in the presence of a treatment agent recipe. The impregnation may further include the application of pressure and heat to the thermally modified wooden object while the object is in the presence of a treatment agent recipe. The resulting thermally modified and impregnated wooden product has substantially the same dimensions as the pre-formed thermally modified wooden object.
The pre-formed thermally modified wooden object may be in the shape of dimensioned lumber, musical instruments, dimensioned building materials, furniture, outdoor wood products, gun stocks, fencing, fence posts, wood-poles, decking material, siding, watercraft products, aircraft products, flooring, statues, artwork, frames, sports equipment, tools, handles, ledgers, baskets, animal and livestock containment and housing structures, wooden weaponry, blocks, toys, or other crafted wooden objects.
The one or more treatment agents may be natural or synthetic and may include at least one of oil, polymerizing agents, lacquering agents, plasticizing agents, varnishing agents, and combinations thereof.
Another method of producing a thermally modified and impregnated wooden product is also provided. At least one piece of wood is thermally modified and subsequently formed into a wooden object by hand, tool, machine, a computer numerical control machine, or a combination thereof. The wooden object is then impregnated with one or more treatment agents to produce the thermally modified and impregnated wooden product, where the thermally modified and impregnated wooden product has substantially the same dimensions as the wooden object.
Thus has been broadly outlined the more important features of the present method of producing a thermally modified and impregnated wooden product so that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
Objects of the present method of producing a thermally modified and impregnated wooden product, along with various novel features that characterize the invention are particularly pointed out in the claims forming a part of this disclosure. For better understanding of the method of producing a thermally modified and impregnated wooden product, its operating advantages and specific objects attained by its uses, refer to the accompanying drawings and description.
The present invention has utility as a method of producing a thermally modified and impregnated wooden product that is pre-formed prior to impregnation and resists deformation during impregnation. The present invention is particularly advantageous for producing a wooden product that has at least one of increased strength, ultraviolet-resistance, dimensional stability, moisture resistance, heat resistance, tonal qualities, fungal resistance, insect resistance, flexibility, punch-through resistance, fire resistance, deep-freeze-damage resistance, bacterial resistance, contagion resistance, chemical resistance, salt-damage resistance, marine invasive-species resistance, terrestrial invasive species resistance, structural integrity, or a combination thereof. Further, the present invention may produce wooden products with deep-colorization combined with deep-strengthening as well as enhanced fire resistance and even produce wooden products having fire retardation substances introduced deep into the wooden product. Finally, embodiments of the methods described herein may further reduce overall operating/manufacturing costs, specialize the impregnation process for a given wood species or wooden product, and/or streamline production for companies that manufacture wooden products. The following description of various embodiments of the invention is not intended to limit the invention to those specific embodiments, but rather to enable any person skilled in the art to make and use this invention through exemplary aspects thereof.
It is to be understood that in instances where a range of values are provided, the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of that range. By way of example, a recited range of 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.
As used herein, the term “treatment agent” refers to an agent or substance for treating wood. The “treatment agent” may be natural or synthetic. Examples of “treatment agents” include oil, polymers, polymerizing agents, lacquering agents, plasticizing agents, and varnishing agents. More particularly, the “treatment agents” may include vegetable oils (drying, semi-drying, or non-drying oils), epoxidized oils (epoxidized jatropha oil), synthetic oils, bioplastics (polylactide), polyesters, polystyrene, acrylate polymers, poly(methyl methacrylate), polycarbonates, comonomers (such as butyl acrylate and methacrylic acid), copolymers, epoxies, natural resins, acrylic resins, shellac, lacquers, nitrocellulose lacquers, plasticizers, thinning solvents, pigments, tints, stains, and dies. Thinning solvents may further include acetone, n-Butanol, dimethylformamide (DMF), ethylbenzene, glycol ethers (such as 2-butoxyethanol), methyl ethyl ketone (MEK), mineral spirits, n-butyl acetate, naphtha, toluene, turpentine, xylene, citrus solvent, and other thinners.
As used herein, the term “treatment agent recipe” refers to a mixture of two or more treatment agents to aid in impregnation.
Also as used herein, the term “pre-formed thermally modified wooden object” refers to an object made of wood that has been: a) thermally modified; and b) crafted, shaped, formed, assembled, or dimensioned into a final end-user product, a constituent thereof, or considerably crafted, shaped, formed, or otherwise dimensioned to that end (e.g., a wooden product that is greater than 50% formed into a final end-user product, or a constituent thereof). Examples of pre-formed thermally modified wooded objects are described below with reference to
With reference now to the drawings, and in particular
Referring to
The impregnation may occur in an impregnation container, such as an autoclave, capable of controlling containment pressure and temperature necessary for each specific treatment agent recipe, wooden object, wooden species, or combinations thereof. The pre-formed thermally modified wooden object may be placed inside the impregnation container, where one or more treatment agents are pumped into the container to immerse (either partially or completely) the wooden object therein. The wooden object is subsequently impregnated using any of the aforementioned techniques (e.g., application of pressure, heat, treatment agent recipe, or a combination thereof). In some embodiments, prior to immersing the wooden object in the treatment agent(s), air or fluid may be removed from the container with the wooden object therein by reducing the pressure inside the container. Removing air may improve the impregnation. Further, it should be appreciated, that the depth of impregnation may be dependent upon the species of the wooden object, the thickness at one or more regions of the wooden object, a pressure-component of one or more treatment agents, a heat component of one or more treatment agents, the treatment agents themselves, and any combination thereof, all of which may be adjusted accordingly to improve penetration depth and/or create a wooden product having specific characteristics and/or properties without deviating from the scope of the invention. It should further be appreciated, that the pressures and temperatures required to effect penetration for a given wood species, treatment agent(s), and/or wooden product may be known in the art and/or determined experimentally without deviating from the scope of the invention.
Advantageously, the resulting thermally modified and impregnated wooden product has substantially the same dimensions as the pre-formed thermally modified wooden object. In other woods, impregnating a pre-formed thermally modified wooden object results in minimal, if any, deformation of the wooden object during impregnation. In some embodiments, the term ‘substantially’ refers to 0% to 1% dimensional deformation of the wooden object during impregnation. In other embodiments, ‘substantially’ refers to 1% to 5% dimensional deformation of the wooden object during impregnation. Further, it should be appreciated, that although some species of wood may deform more than others during impregnation, this deformation is easily addressed by varying the treatment agent recipe based upon the wood species.
Referring to
At least one piece of wood 11 may be obtained from conventional sources and thermally modified by a controlled pyrolysis process (e.g., Westwood process, Plato process, oil heat treatment). In some embodiments, the piece(s) of wood 11 is kiln-dried in an oven using techniques known in the art prior to thermal modification.
The thermally modified wood 13 is then formed into a wooden object 17a. The wooden object 17a may be formed by modifying the thermally modified wood by hand, tool, machine, a computer numerical (CNC) machine, or a combination thereof. The wooden object 17a may be further formed by assembling two or more pieces of the aforementioned modified wood. For example, a first piece of thermally modified wood may be modified into the shape of a table top, while a second piece of thermally modified wood is modified into the shape of table legs, where the table top and table legs are subsequently assembled to form a wooden table 18a. In any case, the resulting formed wooden object refers to an object that has been crafted, shaped, formed, assembled, or dimensioned into a final end-user product, a constituent thereof, or considerably crafted, shaped, formed, or otherwise dimensioned to that end (e.g., a wooden product that is greater than 50% formed into a final end-user product, or a constituent thereof). Examples of formed wooden objects 17a, as illustrated in
After forming the wooden object 17a, the wooden object 17a is impregnated using any of the aforementioned impregnation techniques (Block S16) (e.g., applying pressure, heat, a treatment agent recipe, or a combination thereof). The impregnation may occur in an impregnation container 19, such as an autoclave, for controlling the containment pressure and temperature therein as described above. The wooden object 17a may be partially or completely immersed in the one or more treatment agents. The resulting product is a thermally modified and impregnated wooden product 17b. Advantageously, the dimensions of the thermally modified and impregnated wooden product 17b are substantially the same as the wooden object 17a. The term ‘substantially’ here has the same aforementioned meaning.
In particular embodiments, the impregnation container 19 may be considerably reduced in size compared to traditional industrial sized autoclaves since the wood is already formed. In some embodiments, the impregnation container 19 may be a benchtop device for impregnating smaller wooden products. In other embodiments, the interior geometry of the impregnation container 19 may be sized and/or dimensioned to fit one or more particular products to streamline manufacturing. In a further embodiment, the impregnation container 19 is industrial in size but specialized for a particular wooden product. Overall, it should be appreciated, that by forming the wooden objects 17a prior to impregnation, the final product may have superior properties and/or characteristics and may reduce overall manufacturing costs, specialize the impregnation process for a given wood species or wooden product, and/or streamline production for companies that manufacture wooden products.
