Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-04-06
2002-11-19
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S393000, C264S188000
Reexamination Certificate
active
06482514
ABSTRACT:
TECHNICAL FIELD
The present invention relates to rayon fibers superior in deodorization performance and to a method for producing the rayon fibers.
BACKGROUND ART
Deodorization treatment has been conventionally applied to rayon fibers used as wadding and rayon fibers for clothing in order to prevent quilts or clothes from offensive smelling. The deodorization treatment has been also applied to rayon fibers used in carpet, wall cloth, or the like, in order to prevent a room from offensive smelling by adsorbing it into the carpet or the like.
As one of such deodorant rayon fibers, a deodorant rayon fibers containing fine grains of activated charcoal, into which metal complex of phthalocyanine is adsorbed, in a matrix of the rayon fiber are known (the Japanese Patent Publication (unexamined) No. 300769/1988). This deodorant rayon fibers transforms odor molecules into odorless molecules (odorless components) through a chemical reaction between the metal complex of phthalocyanine adsorbed by the fine grains of activated charcoal and the odor molecules. It is to be noted that, in this known art, the fine grains of activated charcoal are used just for carrying the metal complex of phthalocyanine, and not for adsorbing the odor molecules. This is because when the fine grains of activated charcoal are contained in the matrix of the rayon fiber, micropores of the fine grains of activated charcoal are coated or covered by cellulose and the power for adsorbing the odor molecules is almost lost. In other words, when such a type of deodorant as adsorbing the odor molecules into micropores (activated charcoal is typical) is implanted (contained) in the matrix of the rayon fiber, its deodorization performance is lost. As a result, it is impossible to give any deodorization performance to the rayon fibers. This has been a common technical sense in the field of art.
However, the inventors have found that a specific deodorant among the deodorants of the type adsorbing the odor molecules into the micropores does not substantially lose its deodorization performance even if the deodorant is implanted in the matrix of the rayon fiber. Moreover, the inventors have also unexpectedly found that deodorization performance is further improved for a certain kind of odor components as compared with the deodorization performance achieved by using the specific deodorant alone, and that the specific deodorant produces minus ions under specific conditions. (It is usually said that the more minus ions exist, the more favorable environment is provided for human body.)
SUMMARY OF THE INVENTION
The present invention was made on the basis of the foregoing discoveries.
The present invention relates to deodorant rayon fibers implanting fine grains, which are produced by milling white charcoal made by carbonizing an oak, in a matrix of the rayon fiber. Scratch hardness of the white charcoal is prefferably more than 15 degree. The degree of the scratch hardness is set on the basis of the scratch hardness of steel and lead. That is, the scratch hardness of steel is 20 degree, and the lead is 1 degree.
It is preferable in the present invention to use “Binchotan” charcoal which is a kind of white charcoal. “Binchotan” charcoal is a white charcoal made in Japan. “Binchotan” charcoal is produced by carbonizing “Ubamegashi” which is a kind of oak. Scratch hardness of “Binchotan” charcoal is simillar to that of steel or harder than steel.
In general, a viscose rayon fiber is used as the rayon fiber, and it is also preferred to use a cuprammonium rayon fiber or an acetate rayon fiber as the rayon fiber.
The most significant characteristic of the present invention is that fine grains produced by milling white charcoal, prefarably “Binchotan” charcoal, are used as a deodorant to be implanted in the matrix of the rayon fiber. It is considered that once using the fine grains of white charcoal, deodorization function is not easily deteriorated even if the fine grains are implanted in the matrix of the rayon fiber by the following reasons. The white charcoal has a property of being harder than activated charcoal and black charcoal. Espesially, the “Binchotan” charcoal is simillar to or harder than steel in hardness, therefore cannot be cut with a saw, and the teeth of the saw will be nicked instead of cutting the “Binchotan” charcoal. Accordingly, when such a hard white charcoal is mlled into fine grains by applying shock and friction using a hammer mill, a ball mill or the like, the fine grains do not form spheres with smooth surfaces, but their configurations become irregular with recessions and projections. When a large quantity of such fine grains of the white charcoal is implanted in the matrix of the rayon fiber, the projections on the surfaces of the fine grains are in contac with the surface of the rayon fiber at a large number of points “a” as shown in FIG.
1
. (
FIG. 1
is a schematic view showing a cross section of the deodorant rayon fiber). At these points “a”, the projections of the fine grains are sometimes exposed. In other cases, the projections are not originally exposed, but when the surface of the rayon fiber is rubbed, the surface of the rayon fiber is gradually damaged, and consequently, the projections of the fine grains are finally exposed. It is therefore considered that odor components are taken or adsorbed into the fine grains through these exposed portions, whereby the deodorization function is performed.
It is considered that this is the very reason why the deodorization performance of the rayon fibers, in the matrix of which the large quantity of fine grains is implanted, is not easily deteriorated.
The deodorant rayon fibers according to the invention are generally produced as described below. First, the white charcoal is prepared and milled to obtain a large quantity of fine grains of the white charcoal. Any of publicly known methods can be used. It is, however, preferred to use a two-stage milling method in which rough milling is performed at first stage, and fine milling is performed at next stage. The most preferable process method is to use the two-stage milling method in which the rough milling is performed by dry milling, and wet milling performs the fine milling. Any of publicly known milling machines can be used. It is, however, preferred to use a hammer mill, a roll crusher, or the like in the rough milling, and use a ball mill, a tower mill, or the like in the fine milling.
Grain diameter of the fine grains of the white charcoal can be any value as far as the grain diameters are small enough to be implanted in the matrix of the rayon fiber. It is, however, preferred that at least 95% of the large quantity of the fine grains is less than 1.0 &mgr;m in grain diameter. If less than 95% of the fine grains are less than 1.0 &mgr;m in grain diameter, when adding and mixing the fine grains into viscose solution, there arises a possibility that the viscose solution increases its viscosity, eventually resulting in occurrence of gelation. In addition, distribution of the grain diameters of the fine grains can be measured using a coal counter or the like. The large quantity of fine grains obtained in this manner is then dispersed in water to produce water dispersion. In the dispersion of the fine grains in water, it is preferred to use a suitable dispersant such as surfactant, but it is not always necessary to use a dispersant Furthermore, in case that the fine grains are obtained through the wet milling using water (any dispersant such as a surface-active agent is contained therein in some cases), those fine grains are already dispersed in water. Therefore, it is also preferred to use them as they are. Rate of the fine grains in the water dispersion is preferably in the range of 5 to 80 weight percent. If the ratio is less than 5 weight percent, number of the fine grains implanted in the matrix of the rayon fiber tends to be insufficient. On the other hand, if the ratio is more than 80 weight percent, obtaining the water dispersion in which the fine grains are stably dispersed tends to be difficult,
Matsumoto Mitsugu
Nishijima Seiichi
Shimizu Akira
Edwards N.
Jones Tullar & Cooper P.C.
Minabegawa Village Co-op Forest
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