Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1999-11-17
2001-07-24
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S395000, C428S375000, C427S523000, C427S189000
Reexamination Certificate
active
06265064
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a natural fiber containing titanium oxide having various functions such as a deodorizing function, a stain resisting (stain proofing or stain releasing) function, an antibacterial function, and the like, by a photo-catalytic action of titanium oxide, and to a process for producing the same.
BACKGROUND ART
It conventionally has been known that titanium oxide has a photo-catalytic action and thereby decomposes organic matters. The mechanism of decomposing organic matters by the photo-catalytic action can be explained as follows. More specifically, when titanium oxide is irradiated with light beam such as visible radiation, ultraviolet rays, and the like, charge separation occurs so as to generate electrons and highly oxidizable electron holes. The electron holes react with water vapor or oxygen in the air to generate reaction active species such as OH radicals, O
2
−
, etc. Such reaction active species instantaneously decompose organic matters existing around them. At present, titanium oxide is used for the purpose of environmental clean-up, for example, a deodorizing purpose, stain resisting purpose, an antibacterial purpose, etc. by using the photo-catalytic action.
However, when titanium oxide is used in a field of fibers, there are the following problems. First, since titanium oxide is provided in a form of powder, it can be mixed and added to the interior of synthetic fibers. However, since there is no effective method for attaching titanium oxide to natural fibers such as wool, cotton, etc., it has been difficult to attach titanium oxide to natural fibers. Furthermore, even if titanium oxide is attached to natural fibers by some means, the portion of the natural fiber to which titanium oxide is attached is deteriorated by the strong photo-catalytic action of titanium oxide and titanium oxide is easily peeled off. Moreover, as mentioned above, titanium oxide is activated only when ultraviolet rays are present in light to some extent, therefore titanium oxide does not exhibit a sufficient effect inside the house. Furthermore, when titanium oxide is allowed to attach to an animal fiber including protein as a main component, the fibers turn yellow due to the influence of titanium ion.
It is therefore an object of the present invention to provide a natural fiber containing titanium oxide that sufficiently exhibits various functions such as a deodorizing function, a stain resisting function, an antibacterial function, and the like, and to provide a process for producing the same by developing an effective method of attaching titanium oxide to natural fibers in which titanium oxide is not peeled off and no yellowing occurs.
DISCLOSURE OF INVENTION
In order to achieve the above-mentioned object, a natural fiber containing titanium oxide of the present invention has a surface that is plated with titanium oxide.
If the surface of the natural fiber is plated with titanium oxide like this way, the natural fiber per se is not deteriorated and not yellowed due to the photo-catalytic action of titanium oxide. Furthermore, since the attachment by plating is strong, titanium oxide does not peel off. Moreover, since titanium oxide is attached to the surface of the natural fiber, the photo-catalytic action of titanium oxide is sufficiently exhibited, thereby providing the natural fiber with excellent functions such as a deodorizing function, a stain resisting function, an antibacterial function, and the like.
Moreover, in the natural fiber of the present invention, the reason why the natural fiber per se to which titanium oxide is attached is not deteriorated is explained as follows. More specifically, titanium oxide acts on oxygen etc. with which it is in contact so as to produce active oxygen etc. However, the natural fiber of the present invention is plated with titanium oxide, titanium oxide is extremely closely attached to the natural fiber, so that oxygen, etc. cannot enter a place between the natural fiber and titanium oxide. Consequently, reaction active species such as active oxygen, etc. do not develop between the natural fiber and titanium oxide.
When the natural fiber of the present invention is plated with titanium oxide, either the entire or a part of the surface of the natural fiber may be coated with titanium oxide. Preferably, titanium oxide is uniformly attached to the surface of the natural fiber at the rate of 1 to 10% (more preferably at the rate of 2 to 5%) on an area basis.
In the present invention, the plating is not particularly limited, but a chemical plating is preferred.
It is preferable in the natural fiber containing titanium oxide of the present invention that the natural fiber contains protein and is treated to become anionic because the protein-containing natural fiber can further be prevented from yellowing.
It is preferable that the natural fiber is at least one fiber selected from the group consisting of wool, silk and cotton. It is particularly preferable that the natural fiber is an animal fiber such as wool and silk, etc. including protein as a main component.
It is preferable that the natural fiber containing titanium oxide of the present invention contains a noble metal in the plating of titanium oxide. By containing a noble metal, the effect of further improving the photo-catalytic action of titanium oxide can be obtained.
Moreover, in the present invention, titanium oxide and the noble metal in the natural fiber may be an ion or may not be an ion.
It is preferable that the natural fiber containing titanium oxide of the present invention contains gold in the plating of titanium oxide and has a function of oxidizing and decomposing organic matters even in conditions without light.
Next, a process for producing a natural fiber containing titanium oxide comprises plating the surface of the natural fiber with titanium oxide.
For the same reason as mentioned above, it is preferable that the natural fiber is treated to become anionic and then plated with titanium oxide.
It is preferable that natural fiber is treated to become anionic by using at least one acid selected from the group consisting of sulfamic acid, acetic acid, succinic anhydride and citraconic acid.
It is preferable in the process for producing a natural fiber containing titanium oxide of the present invention that a method of plating with titanium oxide comprises: preparing a solution containing titanium ion by adding at least one titanium compound of titanium alkoxide and titanium fluoride to an aqueous solvent; immersing a natural fiber treated to become anionic in this solution; further adding a mixture solution of boric acid, citric acid and D, L-malic acid to this solution and thereby changing the titanium ion to titanium oxide ion; and allowing the generated titanium oxide ion to deposit on the surface of the natural fiber so as to plate the surface.
For the same reason as mentioned above, it is preferable in the process for producing a natural fiber containing titanium oxide of the present invention that the natural fiber contains protein as a main component and a peptide bonding portion in the protein molecule is treated to become anionic. Furthermore, for the same reason as mentioned above, it is preferable that the natural fiber is at least one fiber selected from the group consisting of wool, silk and cotton. An animal fiber such as wool, silk, and the like, is particularly preferred.
It is preferable in the process for producing the natural fiber containing titanium oxide of the present invention that the surface of the natural fiber is plated with a noble metal in addition to titanium oxide.
BEST MODE FOR CARRYING OUT THE INVENTION
The natural fiber containing titanium oxide of the present invention is produced by, for example, the below mentioned process. Hereinafter, “% owf” represents weight % with respect to a processing weight of the natural fibers. For example, in a case where 3 kg of wool is processed, 5% owf additives means 150 g of additives.
First, the surface of the natural fiber is treated to become anionic. An
Edwards N.
Kyorasha Co., Ltd.
Merchant & Gould P.C.
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