Drug – bio-affecting and body treating compositions – Inorganic active ingredient containing – Heavy metal or compound thereof
Reexamination Certificate
2000-05-25
2003-04-01
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Inorganic active ingredient containing
Heavy metal or compound thereof
C424S195180, C424S617000, C424S619000, C424S630000, C424S631000, C424S632000, C424S633000, C424S634000, C424S635000, C424S637000, C424S638000, C424S639000, C424S640000, C424S641000, C424S646000, C424S647000, C424S648000, C424S650000, C424S651000, C424S652000, C424S654000, C424S655000, C424S656000, C424S677000, C424S682000, C424S683000, C424S684000, C424S685000, C424S686000, C424S687000, C424S688000, C424S689000, C424S690000, C424S691000, C424S692000, C424S693000, C424S694000, C424S695000, C424S696000, C424S
Reexamination Certificate
active
06541038
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for treating wood with a metal-containing treating agent that contains a metal, a metal compound and/or a metal ion and to a woody material containing a metal, a metal compound and/or a metal ion obtained by the method. More particularly, the present invention relates to a method for treating wood characterized by causing lignin and/or a lignin derivative to be contained in a treating agent containing a metal, a metal compound and/or a metal ion, oxidizing and/or macromolecularizing of the lignin or derivative thereof in the wood with a polyphenol oxidizing catalyst and/or heating to fix the lignin or derivative thereof together with a metal component, and to a woody article containing a metal, a metal compound and/or a metal ion obtained by the treating method.
PRIOR ART
Conventionally, treating methods that impregnate wood with treating agents containing various metals, metal compounds and/or metal ions have been practiced in order to impart wood with desirable properties such as antimicrobial properties, microbicidal properties, antiseptic properties, insect-repellent properties, antiviral properties, organism-repellent properties, weatherability, fire resistance, or abrasion resistance or to color wood.
In these treating methods, it is generally preferred that the metals, metal compounds and/or metal ions as active ingredients are contained in the wood in larger amounts. Accordingly, there have heretofore been proposed treating agents to which alkanolamines, for example, are added in order to increase permeability of the metal fine powders, fine powders of metal compounds, or metal ions into wood.
For example, Australian Patent No. 519,146 describes a shelf stability improving agent for cellulose-based materials that is composed of an anti-organism agent containing a metal ion capable of forming an ammine complex and a hydroxyalkylamine to which is added an aliphatic monocarboxylic acid having 6 to 12 carbon atoms. This is to form soap from the amine and carboxylic acid so that permeability into the cellulose material can be enhanced.
Also, U.S. Pat. No. 5,426,121 describes a shelf stability agent for wood that has improved anti-organism effect by containing a reaction product between copper cation and an alkoxylated diamine.
Further, JP-A-H08-12504 describes a shelf stability agent composed of an anti-organism composition containing an antiseptic heavy metal and a triazole compound to which a boric acid compound is added. These are contemplated to improve anti-organism properties by use of an auxiliary component as an anti-organism component for improving anti-organism properties such as an organic antimicrobial component with a metal compound.
The treating agents as described above prepared so as to increase the permeability of metal ions are useful for producing treated wood that contains a large amount of metal component. On the contrary, there is a problem in that the metal component that are impregnated could be readily leached from the treated wood when the treated wood is brought into contact with water, so that the useful properties imparted to the wood by the metal component would be degraded. The leached metals, metal compounds and/or metal ions are released to the ambient environment and scattered, thus causing environmental pollution.
In the various kinds of treating methods described above, efforts have been made in order to increase the permeability into cellulose and wood, but no study has been made to prevent leaching. The organic anti-organism agents to be added in these methods in order to improve the anti-organism properties are mostly poor in long term stability as compared with the metal compounds and metal ions. Therefore, it is difficult to maintain excellent anti-organism properties for a long time by mere addition of the organic-based anti-organism components. Furthermore, addition of a considerable amount of organic-based agent causes an increase in a cost of the production.
To prevent leaching of the metal compound and metal ions, many methods have been proposed for insolubilization of the chemical agents before or after the injection thereof. Specifically, one method is that a target article is first treated with a solution of a metal compound as an active ingredient, and then with chemical agent that increases the fixing property of the metal compound. Another method is that a target article is preliminarily treated with a fixing agent for metal ions prior to a metal compound. The aforementioned methods are generally used. In any rate, multi-stage treatment consisting of two or more steps is required. For example, JP-A-H07-88808 discloses a method for treating wood that sequentially conducts a first stage injection treatment with an alkali solution containing a metal compound and sodium silicate and a second stage injection treatment with a neutral salt solution containing an alkaline earth metal salt to insolubilize the sodium silicate by converting it to an alkaline earth silicic acid salt, thus improving the fixing property of the metal component in the target article for treatment.
However, such a multi-stage treatment has the practical problems in the cost and facility. Because after the treatment in the preceding stage, it requires a drying step for enabling an injection with an agent in the subsequent stage, and separate treatment tanks must be provided for the respective treatment stages.
For this reason, development of a method for treating wood has been desired in respect of a metal-containing treating agent that has high permeability into wood and prevents the metal component from leaching from the wood.
Lignin and lignosulfonic acid or lignosulfonic acid salts obtained in pulp industry are typical examples of biomass. Because of the complexity of its structure and the difficulty of decomposition, they have been utilized only as a dispersant, a granulating agent, a chemical agent for concrete, corrosion inhibitor, starting material for adhesive or the like and find insufficient industrial application so that development of other new methods of application has been desired.
OBJECT OF THE INVENTION
Therefore, an object of the present invention is to provide an improved wood treating method by impregnating wood with a metal, a metal compound, and/or a metal ion that can decrease leaching of the metal, metal compound, and/or metal ion in the wood and to provide a woody article treated with a metal-containing chemical agent by the method.
Another object of the present invention is to provide a useful industrial utilization method for lignin, lignosulfonic acid or lignosulfonic acid salts by use of lignin and/or lignin derivatives as a component of a woody treating agent.
SUMMARY OF THE INVENTION
The present inventors have made intensive research with view of developing a new production method for metal-containing wood that can suppress leaching of a metal, a metal compound, and/or a metal ion to a low level. As a result, they have found that impregnation of wood with lignin, lignosulfonic acid, and/or a lignin derivative, which are organic compounds available at low costs and in large amounts, together with a metal, a metal compound, and/or a metal ion, and then oxidation reaction and/or polymerization reaction of the lignin and/or lignin derivative in the wood result in fixing of the metal, metal compound, and/or metal ion in the wood so that their leaching can be considerably suppressed. The present invention has been accomplished on the basis of these findings.
That is, the present invention provides the following method for treating wood, production method for woody material treated with a metal-containing treating agent, and wood and woody material obtained by the methods.
[1] A method for treating wood characterized by impregnating wood with a metal-containing treating agent containing lignin and/or lignin derivatives and a metal, a metal compound, and/or a metal ion and then oxidizing and/or macromolecularizing the lignin and/or lignin derivatives in the wood to
Aoki Hirobumi
Echigo Takashi
Tanaka Keijitsu
Pak John
SDS Biotech K.K.
Sughrue & Mion, PLLC
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