METHOD OF MANUFACTURING ANTIVIRAL FIBER PRODUCT AND ANTIVIRAL MASK CONTAINING THE PRODUCT

Abstract

A method of manufacturing an antiviral fiber product includes impregnating a virus-inactivating agent into a cellulose-based fiber at a temperature of 120° C. to 200° C. and a pressure of 0.0098 MPa to 0.59 MPa. The virus-inactivating agent contains: an aqueous organic acid solution containing 40 wt % to 50 wt % of organic acid partially lactonizing when dissolved in water; zinc oxide nanoparticles dispersed in the aqueous organic acid solution; and zinc salt of organic acid generated by dispersion of the zinc oxide nanoparticles into the aqueous organic acid solution.

Claims

1. A method of manufacturing an antiviral fiber product comprising: impregnating a virus-inactivating agent into a cellulose-based fiber at a temperature of 120° C. to 200° C. and a pressure of 0.0098 MPa to 0.59 MPa, the virus-inactivating agent comprising: an aqueous organic acid solution containing 40 wt % to 50 wt % of organic acid partially lactonizing when dissolved in water; zinc oxide nanoparticles dispersed in the aqueous organic acid solution; and zinc salt of organic acid generated by dispersion of the zinc oxide nanoparticles into the aqueous organic acid solution.

2. The method according to claim 1, wherein the zinc oxide nanoparticles comprise zinc oxide nanoparticles having a diameter of 50 nm to 70 nm.

3. The method according to claim, wherein the zinc salt of organic acid comprises zinc gluconate.

4. The method according to claim 3, wherein the virus-inactivating agent comprises 5000 ppm to 10000 ppm of the zinc gluconate.

5. An antiviral mask comprising a fiber product manufactured by the method according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0049] FIGS. 1(a) and 1(b) show a mask in which the fiber product according to the present invention is contained; FIG. 1(a) is an external view of the mask, and FIG. 1(b) is a partially cutaway view of the mask body having a laminated structure.

DESCRIPTION OF EMBODIMENT

[0050] The method of manufacturing a fiber product according to the present invention uses a virus-inactivating agent in which zinc oxide nanoparticles are dispersed into an aqueous organic acid solution in such a manner that the solution contains 5000 ppm to 10000 ppm concentration of zinc salt of organic acid. The aqueous organic acid solution contains 40 wt % to 50 wt % of organic acid that partially lactonizes when dissolved in water.

[0051] Examples of such organic acids include gluconic acid, acetic acid, citric acid, tartaric acid, malic acid, and lactic acid. Among these acids, gluconic acid is preferable.

[0052] The virus-inactivating agent can be manufactured, for example, as follows. Zinc oxide nanoparticles having a diameter of 50 nm to 70 nm are dispersed and stirred into an aqueous gluconic acid solution containing 40 wt % to 50 wt % of gluconic acid at room temperature so that the resulting zinc gluconate has a concentration of 5000 ppm to 10000 ppm. Throughout the dispersion, the solution temperature is prevented from exceeding room temperature. It has been confirmed that while the zinc oxide nanoparticles are being dispersed and stirred in an aqueous gluconic acid solution, the solution generates heat and undergoes gelation if generating too much heat.

[0053] The virus-inactivating agent thus obtained is impregnated into a cellulose-based fiber at a temperature of 120° C. to 200° C. and a pressure of 0.0098 MPa to 0.59 MPa.

[0054] The high temperature peak and the high pressure peak can either coincide with each other or differ from each other.

[0055] The cellulose-based fiber is not limited to cellulosic natural fibers (e.g., cotton, hemp, flax) and regenerated fibers (e.g., rayon), but can further contain other types of fibers (e.g., synthetic fiber). For example, the cellulose-based fiber can be a cloth made of a blend of cellulose and other materials or a cloth made of different types of fibers. The mass ratio of cellulosic natural or regenerated fiber to the cellulose-based fiber is preferably at least 30%, more preferably at least 50%, and further more preferably at least 70%.

Preparation of the Virus-Inactivating Agent

[0056] Six different samples of a virus-inactivating agent were prepared as follows, which contained different concentrations of zinc gluconate: 30,000 ppm; 10,000 ppm; 7,500 ppm; 5,000 ppm; 3,750 ppm; and 2,000 ppm. Zinc oxide nanoparticles having a diameter of 50 nm to 70 nm were dispersed and stirred into an aqueous solution at room temperature while the solution temperature was prevented from exceeding room temperature. The aqueous solution contained 50% of organic acid (gluconic acid in the embodiment) that partially lactonizes when dissolved in water.

[0057] The zinc oxide in the form of ultra-fine particles is considered to be uniformly dispersed and dissolved in water with the assistance of the organic acid (gluconic acid).

[0058] The process of dispersing the zinc oxide nanoparticles into the aqueous organic acid solution is preferably performed while avoiding a solution temperature rise.

[0059] Next, 0.5 ml of each sample of the zinc gluconate solution (sterile distilled water was used for comparison) and 0.5 ml of avian influenza virus (A/whistling swan/Shimane/499/83(H5N3)10.sup.7.5EID.sub.50/0.1 ml) were mixed in a vortex mixer and reacted for 10 minutes at room temperature (20° C.). The mixture solution of each sample and the virus was diluted ten times with sterile phosphate-buffered saline (PBS) containing an antibiotic. Then, 0.1 ml of the diluted mixture solution was inoculated into the chorioallantoic cavity of each of three 10-day-old chicken embryos. After the embryonated eggs were incubated for two days at 37° C., a hemagglutination test was conducted to check whether the virus grew in the chorioallantoic cavities. Then, the virus infectivity titers were calculated by the Reed and Munch method. The results are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Virus Infectivity Titer (log EID.sub.50/0.1 ml) Zinc gluconate 30,000 ppm  5.75 Zinc gluconate 10,000 ppm  2.5 Zinc gluconate 7,500 ppm 2.25 Zinc gluconate 5,000 ppm 3.5 Zinc gluconate 3,750 ppm 4.5 Zinc gluconate 2,000 ppm 6.25 Sterile distilled water 7.75

[0060] As apparent from Table 1, the virus infectivity titer was the lowest (2.25) when the gluconic acid concentration was 7,500 ppm. The reason for the lowest value is unknown.

Impregnation into Fibers

[0061] A virus-inactivating agent containing 7500 ppm of zinc gluconate was prepared in the same manner as above. An experiment was conducted in which the virus-inactivating agent was impregnated into cellulose fiber (20-count yarn) and cellulose cloth (No. 11 canvas), both of which were commercially available.

Example 1

[0062] First, 1 kg of cellulose fiber and 1 kg of cellulose cloth were put in an autoclave available from Ikeda Scientific Co., Ltd. After this, 2 liter of virus-inactivating agent was added. Then, the virus-inactivating agent was impregnated into the cellulose fiber for ten minutes at 134° C. and 0.23 MPa.

[0063] Afterwards, blow drying was conducted at room temperature, thereby obtaining the cellulose fiber and cellulose cloth of Example 1.

Example 2

[0064] The cellulose fiber and cellulose cloth of Example 2 were prepared in the same manner as in Example 1 except that the temperature and pressure were set at 150° C. and 0.39 MPa, respectively.

Example 3

[0065] The cellulose fiber and cellulose cloth of Example 3 were prepared in the same manner as in Example 1 except that the temperature and pressure were set at 120° C. and 0.10 MPa, respectively, and that the impregnation time was set at 20 minutes.

Comparative Example 1

[0066] The cellulose fiber and cellulose cloth of Comparative Example 1 were prepared in the same manner as in Example 1 except that the temperature and pressure were set at 110° C. and 0.044 MPa, respectively, and that the impregnation time was set at 30 minutes.

Comparative Example 2

[0067] The cellulose fiber and cellulose cloth of Comparative Example 2 were prepared, both of which underwent no treatment.

Washing

[0068] Each of the cellulose fibers and each of the cellulose clothes of Examples 1 to 3 and Comparative Examples 1 and 2 were divided in two amounts, and each half was washed 350 times without detergent in a commercially-available household washing machine.

[0069] The cellulose fibers and cellulose clothes of Examples 1 to 3 and Comparative Examples 1 and 2, both unwashed and washed, were prepared. The same experiment as above was conducted after 0.5 g of each of the fiber products was put in a container containing 1.0 ml of the avian influenza virus solution so as to calculate the virus infectivity titers. In the Table 2 shown below, ◯ (good) indicates that log EID.sub.50/0.1 ml is 3.5 or below, x (poor) indicates that log EID.sub.50/0.1 ml is 5 or greater, and Δ (fair) indicates values between them.

TABLE-US-00002 TABLE 2 Impregnation Process Temperature Pressure Antiviral Activity (° C.) (MPa) Unwashed Washed Example 1 134 0.23 ∘ ∘ Example 2 150 0.39 ∘ ∘ Example 3 120 0.10 ∘ ∘ Comparative Example 1 110 0.044 ∘ x Comparative Example 2 — — x x

[0070] It has been found that the cellulose fiber and cellulose cloth of Comparative Example 2, which had not undergone the impregnation treatment with the virus-inactivating agent, had no antiviral effect. It has also been found that the cellulose fibers and cellulose clothes of examples 1 to 3 had good antiviral activity both before and after they were washed, indicating excellent antiviral properties even after being washed. On the other hand, although the cellulose fiber and cellulose cloth of Comparative Example 1 had the same antiviral properties as those of Examples 1 to 3 before being washed, the properties did not remain after being washed.

Application to Masks

[0071] FIGS. 1(a) and 1(b) show an antiviral mask in which the fiber product according to the present invention is contained; FIG. 1(a) is an external view of the mask, and FIG. 1(b) is a partially cutaway view of the mask body having a laminated structure. As shown in FIG. 1(b), the mask body is formed of a plurality (three in this drawing) of layers of cloth.

[0072] In the drawing, an inner layer 13 is a cloth that will touch the user's mouth. Therefore, this layer should preferably be made of a material which is pleasant to touch. A middle layer 12 will be out of direct contact with both the outside air and the user's mouth. Therefore, applying the present invention to the cloth of this layer can provide long-term antiviral activity. An outer layer 11 will be exposed to the outside air. Applying the present invention to the cloth of this layer can prevent the user's hand, after touching the mask, from being contaminated with viruses.

[0073] Furthermore, the function of blocking pollen and fine particles such as PM 2.5 may be provided to any of these layers.

[0074] The cloth used for the mask is preferably resistant to at least 350 times of washing. The fiber product of the present invention, which is durable to at least 350 times of washing, is preferably made of string and fabric suitable for the properties of the product.

[0075] Furthermore, the present invention is applicable to clothes used for medical and nursing workers, and for hospital and nursing-facility users to prevent hospital-acquired infections.

[0076] In the above-mentioned Examples, gluconic acid was used as an organic acid; however, the present invention is not limited to gluconic acid.

[0077] It should be understood that the above Examples have been described as examples of the implementation of the present invention. The scope of the present invention is shown not by the above description but by the scope of the claims, including all modifications and equivalents.

INDUSTRIAL APPLICABILITY

[0078] The antiviral fiber product according to the present invention maintains bactericidal and antiviral effects even after being washed many times, thereby providing high industrial applicability.

REFERENCE MARKS IN THE DRAWINGS

[0079] 1 antiviral mask [0080] 11 outer layer [0081] 12 middle layer [0082] 13 inner layer