Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Reexamination Certificate
2000-02-02
2002-02-05
Brunsman, David (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
C106S162800, C106S162900
Reexamination Certificate
active
06344077
ABSTRACT:
This is a 371 of PCT/KR98/00119 filed May 12, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aqueous cellulose solution and a rayon fiber produced from the same, and more particularly, to an aqueous cellulose solution containing chitosan and/or chitosan derivatives, or alginic acid and/or alginic acid derivatives, and a water-soluble and antibacterial rayon fiber produced from the solution.
2. Description of the Related Art
In general, a polymer such as rubber, leather, paper, plastic and fiber is not soluble in water. However, water-soluble polymers are also important even though such kind of polymer are few. Water-soluble polymers have been widely used in pharmaceuticals, cosmetics, foods and fiber industries.
Meanwhile, cellulose as a major component of a cell membrane of plants is a linear polymer substance in which D-glucose units are connected by a &bgr;-glucosidic ether bond. Cellulose is not soluble in water due to strong internal bond such as intra- and inter-molecular hydrogen bonds, inter-molecular van der Waals bonds, and high degree of crystallinity caused from intrinsic rigidity. Thus, in order to make cellulose water-soluble, intra- and inter-molecular hydrogen bonds, and inter-molecular van der Waals bonds must be broken. Such solubilized cellulose includes carboxymethyl cellulose, hydroxypropyl cellulose, sulfated cellulose, etc. However, these cellulose are cellulose derivatives which cannot be regenerated back into cellulose because their molecular structures are permanently changed.
In order to produce rayon fiber while maintaining the molecular structure of cellulose, cellulose solution containing sodium cellulose xanthate or cuprammonium cellulose is prepared, and then spun into a coagulating bath, thereby regenerating cellulose. However, reagent such as carbon disulfide CS
2
and Schweitzer's reagent, used to prepare the cellulose solution containing cellulose xanthate or cuprammonium cellulose, are fatally poisonous to humans and pollutes the environment.
Thus, researches have been actively and widely conducted to find a method to solubilize cellulose while minimizing the current pollution problems. As a result, DMF/N
2
O
4
solvent, DMSO/paraformaldehyde solvent, NH
3
/NH
4
SCN solvent, DMAc/LiCl solvent, and NMMO (N-methylmorpholine-N-oxide) solvent have been developed. However, cellulose solutions prepared by such solvent systems are organic solutions, not aqueous solutions, so that costs required for recovering the solvents are high.
Thus, the present inventor has conducted numerous experiments to obtain an aqueous cellulose solution without causing the above problems, and provided an aqueous cellulose solution in a homogeneous phase. The aqueous cellulose solution is obtained by mixing ambidextrous cellulose having a negative charge or positive charge depending on the peripheral circumstances with a water-soluble polymer having the same negative or positive charge as that of the ambidextrous cellulose. Accordingly, in the aqueous solution, cellulose is easily dispersed into the water-soluble polymer by the electrical repelling force, thus providing homogeneous aqueous cellulose solution in which cellulose is mixed with the water-soluble polymer homogeneously at the molecular level. Also, the present inventor has noticed that a fiber or film formed by wet-spinning the homogeneous cellulose solution into a coagulating bath such as low-temperature water or acetone has water-soluble or water-resistant property depending on the composition of the coagulating bath, and also has antibacterial property.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide an aqueous cellulose solution capable of minimizing the problems of pollution.
It is another objective of the present invention to provide a rayon fiber produced from the aqueous cellulose solution.
Accordingly, to achieve the first objective, there is provided an aqueous cellulose solution comprising: a first component containing at least one selected from the group consisting of alkali cellulose and cellulose derivatives; and a second component containing at least one selected from the group consisting of soluble chitosan and chitosan derivatives, or alternatively at least one selected from the group consisting of soluble alginic acid and alginic acid derivatives, wherein the first and second components are homogeneously mixed without phase separation.
To achieve the second objective, there is provided a rayon fiber produced by wet-spinning an aqueous cellulose solution into a coagulating bath, wherein the aqueous cellulose solution comprises: a first component containing at least one selected from the group consisting of alkali cellulose and cellulose derivatives; and a second component containing at least one selected from the group consisting of soluble chitosan and chitosan derivatives, or alternatively at least one selected from the group consisting of soluble alginic acid and alginic acid derivatives, and the first and second components are homogeneously mixed without phase separation.
Preferably, the total content of the first and second components is 4~12 wt % based on the total weight of the cellulose solution.
Preferably, the cellulose derivative is at least one selected from the group consisting of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sulfated cellulose, methyl cellulose, ethyl cellulose, n-propyl cellulose and isopropyl cellulose.
Preferably, the chitosan derivative is at least one selected from the group consisting of alkali chitin, carboxymethyl chitin, hydroxypropyl chitosan, sulfated chitosan, succinyl chitosan, chitosan lactate, sodium chitosan acetate and quaternary ammonium salt of chitosan.
Preferably, the quaternary ammonium salt of chitosan is at least one selected from the group consisting of trimethylammonium chitosan halide, triethylammonium chitosan halide and triisopropylammonoum chitosan halide.
Preferably, the alginic acid derivative is at least one selected from the group consisting of sodium alginate, calcium alginate, potassium alginate and magnesium alginate.
Preferably, the cellulose solution further comprises a base compound of 0.01~5 wt % based on the total weight of the cellulose solution, and the base compound is at least one selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)
2
) and magnesium hydroxide (Mg(OH)
2
).
Preferably, the coagulating bath is water.
Preferably, the coagulating bath is water containing 5~25 wt % of at least one selected from the group consisting of zinc sulfate, sodium sulfate, ammonium sulfate, sodium chloride and calcium chloride.
Preferably, the coagulating bath is water containing 3~8 wt % of at least one selected from the group consisting of chitosan and chitosan derivatives, and 5~25 wt % of at least one selected from the group consisting of zinc sulfate, sodium sulfate, ammonium sulfate, sodium chloride and calcium chloride.
Preferably, the coagulating bath is water containing 3~8 wt % of at least one selected from the group consisting of alginic acid and alginic acid derivatives, and 5~25 wt % of at least one selected from the group consisting of zinc sulfate, sodium sulfate, ammonium sulfate, sodium chloride and calcium chloride.
Preferably, the temperature of the coagulating bath is 4~15° C.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An aqueous cellulose solution of the present invention is obtained by dissolving a mixture containing alkali cellulose and/or cellulose derivatives as a first component, and a water-soluble chitosan and/or derivatives thereof, or a water-soluble alginic acid and/or derivatives thereof, as a second component, in water at room temperature.
In the present invention, in general, cellulose can be separated and purified from wood. Cellulose and cellulose derivatives having a degree of polymerization of 300~600 are favorable in terms of convenience in the spinning process, and material properties of ra
Brunsman David
Leydig , Voit & Mayer, Ltd.
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