JP2022174112A - Antiviral sheet containing cellulose fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antiviral sheet containing cellulose fiber, having excellent antiviral activity.

SOLUTION: The present invention discloses an antiviral sheet containing cellulose fiber. In the antiviral sheet, an antiviral activity value (Mv) to influenza virus or feline calicivirus measured on the basis of JIS L 1922: 2016 (Textiles-Determination of antiviral activity of textile products) is 2.0 or more.

SELECTED DRAWING: None

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to an antiviral sheet. More specifically, it relates to antiviral sheets containing cellulose fibers.

A functional sheet obtained by adding a functionality-imparting agent to a sheet-like base material is used in various industrial fields. Examples of functions generally include deodorant, antibacterial, heat resistance, moisture resistance, weather resistance, solvent resistance, abrasion resistance, electromagnetic wave shielding, etc. Examples of applications include packaging materials (paper containers, cardboard, resin film etc.), building materials (wallpaper, decorative paper, mattress sheets, etc.), daily necessities (deodorants, fragrances), industrial goods (filters, wipers, etc.), medical supplies (masks, etc.), clothing, other paper products (calendars, etc.) etc. Among them, deodorant and antibacterial functions are often required in many industrial fields.

In addition to the above functions, functional sheets are required to have mechanical properties such as tensile strength, tear strength, bursting strength, and, if necessary, air permeability and printability.

Various techniques have been proposed for imparting deodorizing and antibacterial functions to sheet-like substrates. For example, in Patent Documents 1 and 2, a hydrophilic polymer substrate such as cellulose fibers is impregnated with an aqueous solution of either a silicon compound or an aluminum compound, which are constituents of zeolite, and a basic substance and the other aqueous solution are impregnated. An inorganic porous crystal-hydrophilic polymer composite has been proposed in which zeolite is supported inside cellulose fibers by mixing and further impregnating this, and by further supporting metals on the zeolite, antibacterial effects and It is disclosed that a deodorizing effect can be imparted.
Further, in Patent Document 3, after impregnating a fiber structure with an aqueous solution containing a silicon compound and a basic substance and an aqueous solution containing an aluminum compound and a basic substance, the silicon compound and the aluminum are dissolved inside the cellulosic fiber by moist heat heating. A cellulosic fibrous structure is disclosed which is reacted with a compound to form a zeolite, which is a silica-alumina porous body. Furthermore, it is disclosed that antibacterial and antifungal properties can be imparted by introducing metal ions into the porous silica/alumina material.

Patent Document 4 discloses an antibacterial cellulose fiber containing one or more silver-based antibacterial agents selected from silver zeolite, silver zirconium phosphate, silver calcium phosphate, and silver-soluble glass. .

Further, Patent Document 5 discloses a paper base material containing oxidized pulp, wherein the amount of carboxyl groups in the oxidized pulp is 1.0 mmol/g to 2.0 mmol/g with respect to the absolute dry weight of the oxidized pulp. A paper base material for a functional sheet having deodorizing properties and the like is disclosed.

JP-A-10-120923 JP-A-11-315492 JP 2008-031591 A JP-A-11-107033 WO2014/097929

However, those described in Patent Documents 1 to 4 are mere mixtures of cellulose fibers and inorganic compounds containing metal components, and the cellulose fibers and inorganic compounds containing metal components are chemically and firmly bonded. It does not mean that In other words, since inorganic compounds containing metal components do not form a physical or chemical network like fibers, when functional sheets are manufactured using them, the mechanical strength of the base material, such as tensile strength and tear strength, is reduced. In addition to the deterioration of the properties, there is a problem that the inorganic compound containing the metal component falls off from the base material.
In addition, conventional functional sheets have a problem that their antiviral function and the like deteriorate when placed in a high-humidity environment or wet. Here, the wet state means, for example, a state in which 100% or more of water is contained in a mass ratio with respect to a constant mass of the nonwoven fabric after drying.
In view of such circumstances, an object of the present invention is to provide an antiviral sheet containing cellulose fibers with excellent antiviral activity.

The present invention includes, but is not limited to, the following aspects.
[1] An antiviral sheet containing cellulose fibers,
The above sheet having an antiviral activity value (Mv) against influenza virus or feline calicivirus measured in accordance with JIS L 1922:2016 (testing method for antiviral properties of textile products) of 2.0 or more.
[2] The cellulose fibers comprise, as cellulose fibers having an anionic group, oxidized cellulose fibers having a carboxyl group or a carboxylate group; and/or carboxyalkylated cellulose fibers having a carboxyalkyl group; ] sheet described in.
[3] The sheet according to [2], wherein the amount of anionic groups in the cellulose fibers having anionic groups is 0.01 to 3.0 mmol/g.
[4] The cellulose fibers contain Cu and/or Ag as metal ions and/or metal particles, and the content of metal ions and/or metal particles in the sheet is 6.3 mg/g or less [1] The sheet according to any one of to [3].
[5] The sheet according to any one of [1] to [4], wherein the cellulose fibers contain Cu as metal ions and/or metal particles.
[6] The sheet according to any one of [1] to [5], containing LBKP and/or waste paper pulp.
[7] The sheet according to any one of [1] to [6], wherein the total content of metal ions and/or metal particles in the sheet is 0.20-6.3 mg/g.
[8] The sheet according to any one of [1] to [7], which has an antiviral activity value (Mv) against influenza virus or feline calicivirus of 3.0 or more.
[9] The sheet according to any one of [1] to [8], wherein the sheet is paper.
[10] The sheet of [9], which has a clear coating layer on one or both sides.
[11] The sheet according to any one of [1] to [10], which has a basis weight of 20 to 250 g/m ² .
[12] A method for producing a sheet according to any one of [1] to [11], comprising the step of forming a sheet from a slurry containing cellulose fibers.
[13] The method of [12], wherein the slurry further contains LBKP and/or waste paper pulp.
[14] The method of [12] or [13], wherein the sheet comprises 1 to 15% by weight of the cellulose fiber.
[15] The method according to [12] to [14], wherein the slurry contains calcium carbonate, the basis weight of the sheet is 20 to 250 g/m ² , and the sheet is made using a paper machine.

According to the present invention, it is possible to provide an antiviral sheet containing cellulose fibers and having excellent antiviral properties. According to the present invention, since the functional component contributing to antiviral activity and the like remains firmly in the sheet, functions such as antiviral activity are sufficiently exhibited.

The cellulose fiber-containing sheet according to the present invention is an antiviral sheet having a single-layer structure or a multi-layer structure. Specifically, the antiviral sheet according to the present invention conforms to JIS
Antiviral activity value (Mv) against influenza virus or feline calicivirus measured based on L 1922:2016 (antiviral test method for textile products) is 2.0 or more, and antiviral activity value is 2.5 or more or 3.0 or more.

The antiviral sheet according to the present invention may have one or more other functions in addition to antiviral properties. Examples of functions possessed by the antiviral sheet according to the present invention include deodorant, antibacterial, heat resistance, moisture resistance, weather resistance, solvent resistance, abrasion resistance, electromagnetic wave shielding, etc., but the present invention is preferable. In embodiments, the antiviral sheet has deodorizing and/or antibacterial functions.

The application of the antiviral sheet according to the present invention is not particularly limited, and it can be used for any application that requires an antiviral function. Applications of antiviral sheets include, for example, packaging materials (paper containers, corrugated cardboard, resin films, wrapping paper, etc.), building materials (wallpaper, decorative paper, mattress sheets, etc.), sanitary products (diapers, sanitary products, wipers, masks, etc.). Wet towels, gauze, cotton swabs, etc.) Daily necessities (deodorizing materials, aromatic materials, food filters, clean filters, lunch mats, tray masks, table cloths, draining nets, cooking papers, cooking sheets, lye removing sheets, kitchen towels, cloths, etc.) Aprons, pot holders, toilet seat covers, anti-splash sheets for toilet floors, foot wipes, wet wipes, disposable slippers, carpet base materials, shoe insoles, suit covers, handbags, condensation sheets, book covers, vacuum cleaner paper packs, Sticky notes, bookmarks, notebooks, notebook covers, pet sheets, disposable sheets, pillowcases, duvet covers, wipes, etc.), industrial supplies (industrial filters, industrial wipers, automotive interior materials, etc.), medical supplies (masks, protective clothing) , surgical gowns (caps, aprons, underwear), antibacterial mats, cleaning cloths, medical tapes, etc.), clothing (disposable underwear, etc.), gardening and agricultural materials (gardening sheets, agricultural sheets, nursery sheets, fruit bags, etc.), headrest covers (bullet trains and automobiles), and other paper products (calendars, etc.).

The antiviral sheet according to the present invention may have a single-layer structure or a multi-layer structure, but in the case of a multi-layer structure, at least one layer should contain cellulose fibers. In addition, cellulose fibers carrying metal ions and/or metal particles, which will be described later, exhibit excellent antiviral functions even when contained in any layer, but viruses generally adhere to the outermost layer of the sheet, From the viewpoint of efficiently expressing the antiviral function, the cellulose fibers carrying metal ions and/or metal particles are preferably contained in the outermost layer of the sheet.

The antiviral sheet according to the present invention contains cellulose fibers, and the cellulose fibers have anionic groups on their surfaces, and are composed of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn and Cu. preferably contains one or more metal ions and/or metal particles selected from the group of elements. The anionic group is preferably a carboxyl group or a carboxylate group, and preferably has an ionic bond with a metal ion. In the present invention, it is preferable to have at least one layer containing cellulose fibers carrying metal ions and/or metal particles (hereinafter also referred to as “metal-containing cellulose fibers”). From the viewpoint of high activity and safety, the metal ion preferably contains Cu and/or Ag, more preferably Cu. Ag and Cu are highly safe compared to Hg and the like, and can be suitably used for paper applications that are often directly touched by hand. In addition, Cu is less susceptible to the effects of halogen, temperature, etc., compared to Ag, and is known to exert its effects stably. The paper of the present invention containing can be used in all environments and applications.

Raw materials other than the metal-containing cellulose fibers are not particularly limited, and known raw materials can be used. For example, one or more types of other materials such as cellulose fibers that do not carry metal ions or metal particles (hereinafter also referred to as "general cellulose fibers"), synthetic fibers, resins, and inorganic substances may be included.
The sheets of the present invention may contain fillers. The content of the filler in the sheet is not particularly limited, but it is preferably in a range not exceeding 20% by weight of the sheet weight, and may be 10% by weight or less or 5% by weight or less. Examples of fillers include heavy calcium carbonate, light calcium carbonate, silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice stone powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, Calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, calcium silicate, montmorillonite, pentonite, graphite, aluminum powder, molybdenum sulfide and the like.

Other materials include, but are not limited to, bulking agents, dry paper strength improvers, wet paper strength improvers, drainage improvers, retention improvers, dyes, sizing agents, aluminum sulfate, etc., if necessary. may be used. The total content of materials other than fillers should preferably not exceed 10% by weight of the sheet weight.

Moreover, the manufacturing method of the sheet is not particularly limited, and a known method can be used. For example, a method of ejecting water in which the raw material is dispersed and dehydrating it by pressure or heat (so-called wet method), or a method of ejecting the raw material in a dry state and forming a sheet by similarly applying pressure or heat (so-called dry method). can be a method. Since cellulose fibers are hydrophilic, it is preferable to form the sheet by a wet method.
In the present invention, a sheet can also be produced by mixing pulp slurry (paper stock) with the above cellulose fiber and making paper using the sample, in the same manner as a normal paper sheet. A known paper machine such as a fourdrinier paper machine, a twin wire paper machine, a cylinder paper machine, or the like can be used for papermaking, and the papermaking conditions are not limited.
Moreover, the antiviral sheet according to the present invention may be subjected to a known surface treatment such as calendering, if necessary. A known treatment apparatus can be used for the surface treatment, and the conditions are not limited.
The antiviral sheet according to the present invention may optionally be provided with a coating layer containing no pigment (clear coating layer) on the surface of the sheet. The sheet of the present invention preferably has a clear coating layer on one or both sides of the sheet, more preferably at least a clear coating layer containing starches. By having a clear coating layer, when the sheet of the present invention is paper, it is possible to obtain paper that is particularly excellent in smoothness, surface strength, and printability. In addition, although the reason is not clear, the sheet of the present invention has excellent antiviral activity and antibacterial/deodorizing function even when the sheet surface is covered with a clear coating layer.
The coating amount of the clear coating layer is preferably 0.01 to 3.0 g/m ² , more preferably 0.1 to 2.0 g/m ² in terms of solid content per side. Clear coating can be formed by applying a coating liquid onto a sheet using a coater (coating machine) such as a size press, gate roll coater, pre-metering size press, curtain coater, or spray coater. . The solid content concentration of the clear coating liquid is preferably 2 to 14% by weight from the viewpoint of boiling and coating amount adjustment. It is preferably from 5 to 450 mPa·s, more preferably from 10 to 300 mPa·s.
In the present invention, starch refers to a mixture of amylose and amylopectin,
Generally, the mixing ratio varies depending on the plant that is the raw material of starch. In the present invention, starches also include starch-derived polymer compounds. Examples of the polymer include denatured, modified, and processed starch. Starches include, for example, raw starch, oxidized starch, esterified starch, cationized starch, and acetylated tapioca starch as raw materials, and auto-modified starch produced by thermochemical or enzymatic denaturation in a papermaking factory. It preferably contains modified starch such as modified starch and hydroxyethylated starch. The clear coating layer of the present invention includes, for example, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose and methylcellulose; denatured alcohols such as polyacrylamide, polyvinyl alcohol, carboxyl-modified polyvinyl alcohol and acetoacetylated polyvinyl alcohol; and styrene-butadiene copolymers. It is also possible to use coalescence, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid ester, etc., and two or more of them may be used in combination. . For the purpose of improving sizing properties, surface sizing agents such as styrene sizing agents, olefin sizing agents, acrylate sizing agents, styrene-acrylic sizing agents and cationic sizing agents may be used in combination. In addition, in the present invention, various auxiliary agents such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, colorants, conductive agents, etc., which are blended in ordinary clear coating, may be added as necessary. used.
^The basis weight of the antiviral sheet according to the present invention is not particularly limited, and a general range can be set as necessary. /m ² , and may be in the range of 20 to 250 g/m ² . If the basis weight is more than 1,000 g/m ² , the easiness of bending and easiness of cutting, which are peculiar to the sheet, may deteriorate, which may cause problems. When the sheet has a multilayer structure, the outermost base paper layer preferably contains the metal ions and/or metal particles of the present invention. Further, when the basis weight of each layer is 10 g/m ² or more, it is preferable from the viewpoint of producing a uniform sheet having minimum strength in handling during production.

The thickness of the antiviral sheet is preferably in the range of 20-500 μm, more preferably in the range of 30-200 μm. When the sheet has a multilayer structure, each layer preferably has a thickness of 20 μm or more from the viewpoint of producing a uniform sheet. The density of the sheet is not particularly limited.

When the antiviral sheet according to the present invention has a multilayer structure, each layer may be produced one by one and then laminated by a known method, or the layers may be formed while sequentially laminating each layer. Alternatively, a sheet may be manufactured by a so-called simultaneous multilayer method in which multiple layers are formed at once while simultaneously discharging raw materials for each layer. A method for adhering each layer is not particularly limited, and a known method can be used. For example, a method of using an adhesive, a method of passing between heated rolls, or a method of fusing the layers by applying hot air, and the like can be mentioned.
When the antiviral sheet according to the present invention has a multi-layer structure, the outermost layer may be laminated with one or more layers. You may have it in an outer layer. Alternatively, single-layer sheets may be simply laminated, and one or more layers may have a three-dimensional structure like corrugated cardboard.

The outermost layer of the antiviral sheet according to the present invention may be printed if necessary.

When the antiviral sheet according to the present invention contains cellulose fibers carrying metal ions and/or metal particles, it preferably contains a total of 0.20 mg/g or more of metal ions and metal particles per 1 g of the sheet. 0.25 mg/g or more is more preferred, 0.30 mg/g or more is even more preferred, and 0.60 mg/g or more is most preferred. Also, the total content of metal ions and metal particles per 1 g of the sheet is preferably 6.3 mg/g or less, and may be 5.0 mg/g or less or 4.0 mg/g or less.
The total content of metal ions and/or metal particles in the sheet per 1 g of the sheet is 0
. By making it 20 mg / g or more and 6.3 mg / g, a sheet excellent in antiviral function etc. can be easily obtained, and excessive metal ions and / or metal particles will suppress the increase in environmental load and coloring of the sheet. can do.

The content of metal ions and metal particles in the antiviral sheet can be measured (quantified) by, for example, ICP optical emission spectrometry (ICP-OES).

Also, the content of the metal-containing cellulose fibers is preferably 0.5% by weight or more relative to the antiviral sheet. If the content of the metal-containing cellulose fibers is too low, it may not be possible to impart sufficient antiviral function. The upper limit of the content is not particularly limited, and can be appropriately adjusted according to the degree of desired antiviral, deodorant, antibacterial function, etc., but may be 100% by weight. The content of metal-containing cellulose fibers may be, for example, 1-80% by weight, 2-60% by weight, 3-40% by weight, and the like.
In addition, since the content of the metal-containing cellulose fibers is preferably 0.5% by weight or more relative to the antiviral sheet as described above, the content of general cellulose fibers in the antiviral sheet is 99.5% by weight. % by weight or less. The lower limit of the content of general cellulose fibers is not particularly limited, and the general cellulose fibers may not be included.

The antiviral sheet according to the invention comprises cellulose fibers. The type of cellulose fiber in the present invention is not particularly limited, and any type can be used as required. Moreover, two or more kinds of cellulose fibers among them may be mixed at an arbitrary ratio and used. The origin of the cellulose fiber is not particularly limited, and examples thereof include cellulose fibers derived from plants, animals, algae, and microorganisms. Among them, cellulose fibers derived from plants or microorganisms are preferable. Fibers are particularly preferred.
Plant-derived cellulose fibers include, for example, wood, bamboo, hemp, jute, kenaf, agricultural waste, pulp (unbleached softwood kraft pulp (NUKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP) ), bleached hardwood kraft pulp (LBKP), unbleached softwood sulfite pulp (NUSP), bleached softwood sulfite pulp (NBSP), thermomechanical pulp (TMP), recycled pulp, waste paper pulp, etc.). Examples of cellulose fibers derived from sea squirts include cellulose fibers derived from sea squirts, and examples of cellulose fibers derived from microorganisms include cellulose fibers derived from acetobacter.

The number average fiber diameter and number average fiber length of the cellulose raw material used in the present invention are not particularly limited, and any number average fiber diameter and number average fiber length can be used as required. Moreover, two or more types of cellulose fibers having different number average fiber diameters and number average fiber lengths may be mixed at an arbitrary ratio and used. For example, in the case of softwood kraft pulp (NBKP), which is one of the general pulps, the number average fiber diameter is about 30 to 60 μm and the number average fiber length is about 3 to 5 mm. , a number average fiber diameter of about 10 to 30 μm, and a number average fiber length of about 1 to 2 mm.
When the sheet of the present invention is paper, it preferably contains LBKP and/or waste paper pulp as cellulose fibers. LBKP and waste paper pulp have relatively short fiber lengths, and by including these pulps, it is possible to obtain paper with excellent smoothness, and the paper obtained in this way has excellent surface properties and printability (especially printability). ).
(1) Modification of Cellulose Fiber Cellulose fiber has three hydroxyl groups per glucose unit and can be subjected to various chemical modification treatments. In the present invention, it is preferable to perform a chemical modification treatment having an anionic group after the treatment.
Examples of cellulose fibers into which anionic groups have been introduced include oxidized cellulose fibers having a carboxyl group or a carboxylate group, phosphate-esterified cellulose fibers having a phosphoric acid group, phosphite-esterified cellulose fibers having a phosphite group, Examples include sulfonated cellulose fibers having sulfate groups. In the present invention, in order to introduce metal ions or metal particles into at least a portion of the cellulose fibers in the step described below, modification (oxidation) is performed to introduce carboxyl groups or carboxylate groups into at least a portion of the cellulose fibers. is preferred. In addition, in this specification, the anionic group introduced into the cellulose fiber may be referred to as an acid group.

Here, the carboxyl group means a group represented by -COOH, and the carboxylate group means a group represented by -COO-. The counter ion of the carboxylate group is not particularly limited. As will be described later, when metal particles are formed through ionic bonds with carboxylate groups, the metal ions serve as counters.

The amount of anionic groups in cellulose fibers having anionic groups (acid groups) can be measured, for example, by the following method.
Prepare 60 ml of a 0.5% by mass slurry (aqueous dispersion) of a cellulose fiber sample having an anionic group (acid group), add 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5, and then add 0.05 N sodium hydroxide. The aqueous solution is added dropwise, the conductivity is measured until the pH reaches 11, and the amount of sodium hydroxide consumed (a) is measured in the neutralization stage of the weak acid, where the change in conductivity is gradual. Next, the anion group amount [mmol/g] of the cellulose fiber having an anion group (acid group) is calculated using the following formula. In the formula, x is a value corresponding to the valence of the acid group, which is 1 for a carboxyl group, carboxylate group, phosphite group, and sulfonic acid group, and 2 for a phosphate group.
a [ml] x 0.05/weight of cellulose fiber having anionic group (acid group) [g]/x

Moreover, in the case of carboxyalkylated cellulose fibers having carboxyalkyl groups, the following method can be used to quantify the amount of anionic groups resulting from the carboxyalkylation treatment.
(1) About 2.0 g of carboxymethylated cellulose (absolute dry) is precisely weighed and placed in a 300 mL conical flask with a common stopper.
(2) Add 100 mL of nitric acid methanol solution obtained by adding 100 mL of special grade concentrated nitric acid to 1000 mL of methanol, and shake for 3 hours to convert carboxymethylcellulose salt (carboxymethylated cellulose) into hydrogen-type carboxymethylated cellulose.
(3) Accurately weigh 1.5 to 2.0 g of hydrogen-form carboxymethylated cellulose (absolutely dried) and put it in a 300 mL conical flask with a common stopper.
(4) Wet the hydrogen-type carboxymethyl cellulose with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours.
( ₅ ) Back _- titrate excess NaOH with 0.1N H2SO4 using phenolphthalein as an indicator.
(6) Calculate the degree of carboxyalkyl substitution (DS) by the following formula:
A = [(100 x F'- ₍ 0.1N H2SO4) ₍ mL) x F) x 0.1]/(absolute dry mass of hydrogen-form alkoxyalkylated cellulose (g))
DS = 0.162 x A/(1 - 0.058 x A)
A: Amount of 1N NaOH (mL) required to neutralize 1 g of hydrogen-type carboxyalkylated cellulose
F': factor of 0.1N NaOH F: factor of _{0.1N H2SO4}

A method for introducing anionic groups into glucose units on the surface of cellulose fibers will be described below.

(1-1) Oxidation In the present invention, the method of modification (oxidation) for introducing carboxyl groups or carboxylate groups into cellulose fibers is particularly limited if the cellulose fibers after modification contain carboxyl groups or carboxylate groups. However, a known method can be used.
One example is a method of oxidizing a cellulose raw material in water using an oxidizing agent in the presence of an N-oxyl compound and a substance selected from the group consisting of bromides, iodides or mixtures thereof. According to this method, the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized to generate a group selected from the group consisting of an aldehyde group, a carboxyl group and a carboxylate group. The concentration of the cellulose raw material during the reaction is not particularly limited, but is preferably 5% by weight or less.

An N-oxyl compound means a compound capable of generating a nitroxy radical. Nitroxyl radicals include, for example, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). As the N-oxyl compound, any compound can be used as long as it promotes the desired oxidation reaction.

The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount that can oxidize the cellulose fibers. For example, it is preferably 0.01 mmol or more, more preferably 0.02 mmol or more, relative to 1 g of absolutely dry cellulose. The upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, and even more preferably 0.5 mmol or less. Therefore, the amount of the N-oxyl compound used is preferably 0.01 to 10 mmol, more preferably 0.01 to 1 mmol, and even more preferably 0.02 to 0.5 mmol, relative to 1 g of absolute dry cellulose.

Bromide is a compound containing bromine, and examples thereof include alkali metal bromides that can be dissociated and ionized in water, such as sodium bromide. Also, iodides are compounds containing iodine, and examples thereof include alkali metal iodides. The amount of bromide or iodide to be used may be selected within a range capable of promoting the oxidation reaction. The total amount of bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, relative to 1 g of absolutely dry cellulose. The upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, and even more preferably 5 mmol or less. Therefore, the total amount of bromide and iodide is preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, even more preferably 0.5 to 5 mmol, per 1 g of absolute dry cellulose.

Examples of the oxidizing agent include, but are not limited to, halogens, hypohalous acids, halogenous acids, perhalogenates, salts thereof, halogen oxides, and peroxides. Among them, hypohalous acid or a salt thereof is preferable, hypochlorous acid or a salt thereof is more preferable, and sodium hypochlorite is still more preferable, because it is inexpensive and has a low environmental load.

The amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, and even more preferably 3 mmol or more, relative to 1 g of absolute dry cellulose. The upper limit is preferably 500 mmol or less, more preferably 50 mmol or less, and even more preferably 25 mmol or less. Therefore, the amount of the oxidizing agent to be used is preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, even more preferably 1 to 25 mmol, and most preferably 3 to 10 mmol, per 1 g of absolute dry cellulose.

When the N-oxyl compound is used, the amount of the oxidizing agent used is preferably 1 mol or more per 1 mol of the N-oxyl compound. The upper limit is preferably 40 mol. Therefore, the amount of the oxidizing agent to be used is preferably 1 to 40 mol per 1 mol of the N-oxyl compound.

Conditions such as pH and temperature during the oxidation reaction are not particularly limited, and in general, the oxidation reaction proceeds efficiently even under relatively mild conditions. The reaction temperature is preferably 4°C or higher, more preferably 15°C or higher. The upper limit is preferably 40°C or lower, more preferably 30°C or lower. Therefore, the temperature is preferably 4 to 40°C, and may be about 15 to 30°C, that is, room temperature.

The pH of the reaction solution is preferably 8 or higher, more preferably 10 or higher. The upper limit is preferably 12 or less, more preferably 11 or less. Therefore, the pH of the reaction solution is preferably about 8-12, more preferably about 10-11.
Normally, carboxyl groups are generated in cellulose as the oxidation reaction progresses, so the pH of the reaction solution tends to decrease. Therefore, in order to allow the oxidation reaction to proceed efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution within the above range. Water is preferred as a reaction medium for oxidation because of ease of handling, less occurrence of side reactions, and the like.

The reaction time in oxidation can be appropriately set according to the degree of progress of oxidation, and is usually 0.5 hours or longer. The upper limit is usually 6 hours or less, preferably 4 hours or less. Therefore, the reaction time for oxidation is usually 0.5 to 6 hours, for example about 0.5 to 4 hours.

Oxidation may be carried out in two or more steps. For example, by oxidizing the oxidized cellulose obtained by filtration after the completion of the reaction in the first step, again under the same or different reaction conditions, the reaction can be efficiently It can be oxidized well.

Another example of a modification (oxidation) method for introducing a carboxyl group or a carboxylate group is a method of oxidation by ozone treatment. This oxidation reaction oxidizes at least the hydroxyl groups at the 2nd and 6th positions of the glucopyranose rings that constitute the cellulose, and causes decomposition of the cellulose chain.

Ozone treatment is usually carried out by contacting a cellulose raw material with an ozone-containing gas. The ozone concentration in the gas is preferably 50 g/m ³ or more. The upper limit is preferably 250 g/m ³ or less, more preferably 220 g/m ³ or less. Therefore, the ozone concentration in the gas is preferably 50-250 g/m ³ , more preferably 50-220 g/m ³ .

The amount of ozone added is preferably 0.1 parts by weight or more, more preferably 5% by weight or more, relative to 100% by weight of the solid content of the cellulose raw material. The upper limit is usually 30% by weight or less. Therefore, the amount of ozone added is preferably 0.1 to 30% by weight, more preferably 5 to 30% by weight, based on 100% by weight of the solid content of the cellulose raw material.

The ozone treatment temperature is usually 0° C. or higher, preferably 20° C. or higher. The upper limit is usually 50°C or less. Therefore, the ozone treatment temperature is preferably 0 to 50.degree. C., more preferably 20 to 50.degree. The ozone treatment time is usually 1 minute or longer, preferably 30 minutes or longer. The upper limit is usually 360 minutes or less. Therefore, the ozone treatment time is usually about 1 to 360 minutes, preferably about 30 to 360 minutes. When the ozone treatment conditions are within the above range, excessive oxidation and decomposition of cellulose can be prevented, and the yield of oxidized cellulose is improved.

The resulting product obtained after ozone treatment may be further subjected to additional oxidation treatment using an oxidizing agent. The oxidizing agent used in the post-oxidation treatment is not particularly limited, but examples thereof include chlorine-based compounds such as chlorine dioxide and sodium chlorite; oxygen, hydrogen peroxide, persulfuric acid, peracetic acid and the like. As a method of anti-oxidation treatment, for example, a method of dissolving these oxidizing agents in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and immersing the cellulose raw material in the oxidizing agent solution can be mentioned.

The amount of anion groups in the oxidized cellulose fibers having carboxyl groups or carboxylate groups is preferably 0.01 to 3.0 mmol/g, more preferably 0.20 to 2.2 mmol/g. If the anionic group is less than 0.01 mmol/g, the amount of metal particles present on the surface of the cellulose fibers is insufficient in the step of supporting metal ions or metal particles on the cellulose fibers, which will be described later. Poor antibacterial function. On the other hand, if the anionic group exceeds 3.0 mmol/g, aggregation of the metal particles may occur, and the antiviral, deodorant, and antibacterial functions may be inferior. Yield may decrease.
The amount of anionic groups (carboxyl groups, carboxylate groups) contained in the oxidized cellulose fibers can be adjusted by controlling the amount of oxidizing agent added and oxidation conditions such as reaction time.

(1-2) Etherification For the convenience of introducing metal ions into the cellulose fibers in a subsequent step, any method may be used as the etherification as long as the functional group after the reaction contains a carboxyl group or a carboxylate group. , a known method can be used. Examples include carboxyalkyl etherification such as carboxymethyl (etherification), carboxyethyl (etherification), carboxypropyl (etherification), carboxybutyl (etherification), and carboxyphenyl (etherification). . The carboxymethylation method will be described below as an example of these methods.

A method for carboxymethylation is not particularly limited, and a known method can be used. For example, there is a method of mercerizing a cellulose raw material as a starting raw material and then etherifying it. A common solvent is used for the carboxymethylation reaction. Examples of solvents include water, alcohols (eg, lower alcohols), and mixed solvents thereof. Lower alcohols include, for example, methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, tertiary butanol.

The mixing ratio of the lower alcohol in the mixed solvent is usually 60% by weight or more or 95% by weight or less, preferably 60 to 95% by weight. The amount of solvent is usually 3 times the weight of the cellulose raw material. Although the upper limit is not particularly limited, it is 20 times the weight. Therefore, the amount of solvent is preferably 3 to 20 times the weight.

Mercerization is usually carried out by mixing the base material and the mercerizing agent. Examples of mercerizing agents include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of the mercerizing agent to be used is preferably 0.5-fold mol or more, more preferably 1.0-fold mol or more, and even more preferably 1.5-fold mol or more per anhydroglucose residue of the starting material. The upper limit is usually 20-fold mol or less, preferably 10-fold mol or less, more preferably 5-fold mol or less. 0.5 to 5 times mol is more preferable.

The reaction temperature for mercerization is usually 0° C. or higher, preferably 10° C. or higher. The upper limit is usually 70°C or lower, preferably 60°C or lower. Accordingly, the reaction temperature is generally 0-70°C, preferably 10-60°C. The reaction time is usually 15 minutes or longer, preferably 30 minutes or longer. The upper limit is usually 8 hours or less, preferably 7 hours or less. Therefore, it is usually 15 minutes to 8 hours, preferably 30 minutes to 7 hours.

The etherification reaction is usually carried out by adding a carboxymethylating agent to the reaction system after mercerization. Carboxymethylating agents include, for example, sodium monochloroacetate. The amount of the carboxymethylating agent to be added is generally preferably 0.05-fold mol or more, more preferably 0.5-fold mol or more, and even more preferably 0.8-fold mol or more per glucose residue in the cellulose raw material. The upper limit is usually 10.0-fold mol or less, preferably 5-fold mol or less, more preferably 3-fold mol or less, and therefore preferably 0.05 to 10.0-fold mol, more preferably 0.5 to 5 times mol, more preferably 0.8 to 3 times mol.

The reaction temperature is generally 30°C or higher, preferably 40°C or higher, and the upper limit is generally 90°C or lower, preferably 80°C or lower. Therefore, the reaction temperature is usually 30-90°C, preferably 40-80°C. The reaction time is usually 30 minutes or longer, preferably 1 hour or longer. The upper limit is usually 10 hours or less, preferably 4 hours or less. Accordingly, the reaction time is usually 30 minutes to 10 hours, preferably 1 hour to 4 hours. The reaction solution may be stirred if necessary during the carboxymethylation reaction.

When the cellulose raw material is modified by carboxymethylation, the degree of carboxymethyl substitution per anhydroglucose unit in the resulting carboxymethylated cellulose fiber is preferably 0.01 or more, more preferably 0.05 or more, and 0.10 or more. is more preferable. The upper limit is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.35 or less. Therefore, the degree of carboxymethyl substitution is preferably 0.01 to 0.50, more preferably 0.05 to 0.40, even more preferably 0.10 to 0.30.

(1-3) Esterification In the present invention, the modification (esterification) method for introducing a phosphate group or a phosphite group into the cellulose fiber may be any method, and a known method can be used.

The phosphate-esterified cellulose fiber having a phosphate group and the phosphite-esterified cellulose fiber having a phosphite group are cellulose fibers esterified with a compound having a phosphate group and a phosphite group. Examples of compounds having a phosphoric acid group or a phosphorous acid group include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, esters and salts thereof. These compounds are low cost and easy to handle.

Specific examples of compounds having a phosphate group and a phosphite group include phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, and potassium dihydrogen phosphate. , dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, ammonium metaphosphate, phosphorous acid, nitrite Sodium hydrogen phosphate, ammonium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, phosphorous acid triethyl, triphenyl phosphite, pyrophosphite and the like.
Among them, phosphoric acid, sodium salt of phosphoric acid, potassium salt of phosphoric acid, ammonium salt of phosphoric acid, phosphorous acid, and sodium phosphorous acid because of their high esterification efficiency and easy industrial application. Salt, potassium salt of phosphorous acid, ammonium salt of phosphorous acid are preferred, and sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydrogen phosphite and sodium dihydrogen phosphite are more preferred. Compounds having a phosphate group or a phosphite group may be used singly or in combination of two or more.

The esterification reaction is performed, for example, by reacting a cellulose raw material with a compound having a phosphoric acid group or a phosphorous acid group. Examples of the method of reacting a cellulose raw material with a compound having a phosphate group or a phosphorous group include a method of mixing a cellulose raw material with a powder or an aqueous solution of a compound having a phosphate group or a phosphite group, and a slurry of the cellulose raw material. A method of adding an aqueous solution of a compound having a phosphate group or a phosphite group to .
Among these methods, the method of mixing an aqueous solution of a compound having a phosphoric acid group or a phosphorous acid group with a cellulose raw material or a slurry thereof is preferable because the homogeneity of the reaction is enhanced and the efficiency of esterification is enhanced. The pH of the aqueous solution of the compound having a phosphate group and a phosphite group is preferably 7 or less from the viewpoint of increasing the efficiency of introduction of the phosphate group and the phosphite group, and from the viewpoint of suppressing hydrolysis, from 3 to 7. more preferred.

The lower limit of the amount of the compound having a phosphate group or a phosphite group is preferably 0.2 parts by weight or more, more preferably 1 part by weight or more in terms of phosphorus atoms, per 100 parts by weight of the cellulose raw material. Within this range, the yield of phosphate-esterified cellulose fibers and phosphite-esterified cellulose fibers is likely to be improved. On the other hand, the upper limit is preferably 500 parts by weight or less, more preferably 400 parts by weight or less. Within this range, the compound having a phosphate group or a phosphite group can be efficiently obtained at a yield commensurate with the added amount.

When reacting a cellulose raw material with a compound having a phosphoric acid group or a phosphorous acid group, a basic compound may be added to the reaction system. Examples of the method of adding the basic compound to the reaction system include a method of adding to a slurry of cellulose raw materials, a method of adding to an aqueous solution of a compound having a phosphoric acid group or a phosphorous acid group, or a method of adding a cellulose raw material and a phosphoric acid group or a A method of adding to a slurry of a compound having a phosphoric acid group can be mentioned. The basic compound is not particularly limited, but nitrogen-containing compounds exhibiting basicity are preferred. The term "exhibits basicity" usually means that an aqueous solution of a basic compound exhibits a pink to red color in the presence of a phenolphthalein indicator, or that the pH of the aqueous solution of a basic compound is greater than 7. .

The basic nitrogen-containing compound is not particularly limited as long as the effects of the present invention are achieved. Among them, compounds having an amino group are preferred. Examples include urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine. Among these, urea is preferred because it is low cost and easy to handle.

The amount of the basic compound added is preferably 2 to 1000 parts by weight, more preferably 100 to 700 parts by weight. The reaction temperature is preferably 0 to 95°C, more preferably 30 to 90°C. Although the reaction time is not particularly limited, it is usually about 1 to 600 minutes, preferably 30 to 480 minutes. If the reaction conditions are within any of these ranges, it is possible to prevent excessive introduction of phosphate groups and phosphite groups into cellulose, making it easier to dissolve. The yield of acid-esterified cellulose fibers tends to be improved.

After reacting a cellulose raw material with a compound having a phosphoric acid group or a phosphorous acid group, a suspension is usually obtained. It is preferable that the suspension be dehydrated as necessary and heat-treated after the dehydration. Thereby, hydrolysis of the cellulose raw material can be suppressed. The heating temperature is preferably 100 to 170 ° C., and while water is contained during the heat treatment, heat at 130 ° C. or less (more preferably 110 ° C. or less), remove water, and then heat at 100 to 170 ° C. Heating is more preferred.

It is preferable that the phosphate-esterified cellulose fibers and the phosphite-esterified cellulose fibers are subjected to a washing treatment such as washing with cold water after boiling.

In the phosphate-esterified cellulose fiber and the phosphite-esterified cellulose fiber, the anionic group (phosphate group, phosphite group) contained in the phosphate-esterified cellulose fiber and the phosphite-esterified cellulose fiber is 0.1. ~3.5 mmol/g is preferred.

(1-4) Sulfonation Sulfonated cellulose fibers are cellulose fibers sulfonated with a compound having a sulfate group. Compounds having a sulfate group include, for example, sulfuric acid, sulfamic acid, chlorosulfonic acid, sulfur trioxide, esters and salts thereof. These compounds are low cost and easy to handle.

Sulfamic acid is preferably used in the present invention. Sulfamic acid not only has a lower solubility of cellulose than sulfuric anhydride or an aqueous solution of sulfuric acid, but also has a low acidity, so that the degree of polymerization can be maintained. In addition, there are no restrictions on the handling of sulfuric anhydride and aqueous sulfuric acid solutions, which are strongly acidic and highly corrosive.

The amount of sulfamic acid used can be appropriately adjusted in consideration of the amount of anionic groups (sulfate groups) to be introduced into the cellulose fibers. Sulfamic acid can be used, for example, in an amount of preferably 0.01 to 50 mol, more preferably 0.1 to 30 mol, per 1 mol of glucose units in the cellulose molecule.

(2) Carrying Metal Ions and/or Metal Particles on Cellulose Fibers In the present invention, Ag, Au, Pt, Pd, Ni, and Mn are added to cellulose fibers containing anionic groups, particularly carboxyl groups or carboxylate groups. , Fe, Ti, Al, Zn and Cu. Among them, the use of one or more ions selected from the group of Ag and Cu is preferable because the antiviral, deodorant, and antibacterial functions are further improved, and Cu ions and/or metal particles are more preferable.
Cellulose fibers with anionic groups chemically bond metal ions or metal particles with cellulose fibers. It is also characterized by good performance and strength.

The method for supporting the metal ions on the cellulose fibers is not particularly limited. may be coated on the surface of the film to form a film, and the film may be impregnated with the aqueous solution of the metal compound by dripping. At this time, the film may remain fixed on the substrate, or may be peeled off from the substrate.
Although the detailed mechanism is unknown, by these methods, metal ions derived from metal compounds form ionic bonds by exchanging counterions with sodium ions that have already ionically bonded with anionic groups such as carboxylate groups. , or coordinating to add metal ions to the cellulose fibers. This counter ion exchange is thought to occur due to the difference in ionization tendency between metal ions.

Here, the metal compound aqueous solution is an aqueous solution of a metal salt. Examples of metal salts include complexes (complex ions), halides, nitrates, sulfates, and acetates.

The concentration of the aqueous metal compound solution is not particularly limited, but is preferably 0.2 to 2.2 mmol, more preferably 0.4 to 1.8 mmol, relative to 1 g of cellulose fibers. The contact time of the metal compound may be adjusted as appropriate.

Although the temperature at which the metal compound is brought into contact is not particularly limited, it is preferably in the range of 2 to 50°C. In addition, the pH of the liquid at the time of contact is not particularly limited, but if the pH is low, it becomes difficult for metal ions to bind to the carboxyl groups, so it is preferably in the range of 7 to 13, and the pH is in the range of 8 to 12. is particularly preferred.

In the present invention, the effect is exhibited by introducing metal ions into the cellulose fibers as described above, but there are cases where some of the metal ions are reduced to form metal particles. In addition, if necessary, metal particles can be partially formed on the surface of the cellulose fiber by reducing a part of the metal ions bound to the obtained metal ion-containing cellulose fiber by adding a reducing agent or the like. It is possible. However, from the viewpoint of antiviral, antibacterial, and deodorant functions, it is preferable to use the entire amount of the metal compound as it is, without performing any special reduction treatment.

Although the mechanism of generating metal particles in the cellulose fiber by reducing the metal compound in the metal-containing cellulose fiber obtained above is not clear, it is speculated as follows. The reduction reaction reduces the metal compound in the metal compound-containing cellulose fiber or the ions derived from the metal compound into metal. At this time, the generated metal is carried on the surface of the cellulose fibers. Neighboring metals that are similarly formed coalesce, thus forming particles. On the other hand, metal compounds and the like that are present in the vicinity of the cellulose fibers but have not been bonded to the cellulose fibers are also reduced to form metals. This metal quickly integrates with the metal on the surface of the cellulose fibers to form metal particles.

The reduction reaction may be carried out by a known method, but is preferably carried out so as not to cleave the bond between the metal compound and the cellulose fibers while reducing the metal compound. Examples of such reduction methods include vapor phase reduction methods using hydrogen and liquid phase reduction methods using a reducing agent such as an aqueous sodium borohydride solution.
Conditions such as time and temperature in the gas phase reduction are appropriately adjusted, and the reaction may be carried out at 50 to 60° C. for about 1 to 3 hours, for example. The gas phase reduction reaction is preferably carried out in a state where the oxidized cellulose fibers do not contain water or solvent. In the reduction reaction, the film may remain fixed on the substrate or may be peeled off from the substrate. In the case of liquid-phase reduction, a membrane can be obtained from the above-mentioned dispersion and subjected to the reduction reaction either dried or not dried. Alternatively, the dispersion can be subjected to the liquid phase reduction reaction without drying. The reaction temperature in liquid phase reduction is preferably 4 to 40° C., more preferably room temperature.

The average particle size of metal particles can be obtained from a transmission electron microscope image or X-ray diffraction. In the present invention, the average particle size of the metal particles is preferably in the range of 1 to 50 nm as determined from a transmission electron microscope image. Specifically, as a method for determining the average particle size from a transmission electron microscope image, a transmission electron microscope image of cellulose fibers is prepared, and from the image, the circle equivalent diameter of the primary particles of a plurality of metal particles is determined. A method of averaging the values can be mentioned.

The presence of metal ions and/or metal particles in the cellulose fibers can be confirmed by scanning electron microscope images and ICP emission spectroscopic analysis of the liquid extracted with a strong acid. In other words, the presence of metal ions cannot be confirmed by the scanning electron microscope image, while the presence of the metal can be confirmed by the ICP emission spectroscopic analysis. On the other hand, for example, when the metal is reduced from ions and exists as metal particles, the presence or absence of metal ions can be determined because the metal particles can be confirmed in the scanning electron microscope image. The presence or absence of metal ions can also be determined by scanning electron microscope images and elemental mapping. In other words, the presence of metal ions can be confirmed by elemental mapping, although metal ions cannot be confirmed by scanning electron microscope images.

In the step of supporting the metal ions or metal particles, the total content of the metal ions and/or metal particles with respect to the cellulose fibers is preferably in the range of 10 to 100 mg/g, more preferably in the range of 15 to 80 mg/g. is more preferred, and a range of 20 to 60 mg/g is particularly preferred. If the total amount is less than 10 mg/g, the antiviral, deodorant, and antibacterial functions may be inferior. On the other hand, if the total amount exceeds 100 mg/g, metal ions are likely to be eluted during production, which may increase the load on wastewater treatment.

(3) Beating The cellulose fibers in the present invention may be beaten at least once between before the modification treatment and after the metal loading treatment. This is preferable because the fibers can be efficiently fibrillated without agglomeration. Here, the beating treatment is a treatment for applying a mechanical shearing force to the fibers. By the beating treatment, part of the cellulose fibers are fibrillated and the surface area is increased, so that in general the bonding between the fibers during drying can be strengthened. By carrying out the treatment, the antiviral, deodorant, and antibacterial effects after carrying the metal ions and/or metal particles can be further enhanced.
On the other hand, if the beating treatment is performed excessively to make the cellulose fibers too fine, the yield will decrease when the cellulose fibers are blended with pulp to make paper. It is not preferable because the antibacterial function is lowered. Canadian Standard Freeness (CSF) can be used as an indicator of the degree of beating. Specifically, if the freeness (CSF) is less than 30 ml, the yield of the sheet will decrease, resulting in a decrease in the antiviral, deodorant, and antibacterial functions.
If CSF) exceeds 600 ml, fibrillation is insufficient, and antiviral, deodorant, and antibacterial functions may decrease. Thus, by setting the freeness (CSF) of the cellulose fiber to 30 to 600 ml, the antiviral, deodorant, and antibacterial functions are improved.

The device used for beating is not particularly limited, and any known device can be used. Examples of beating equipment include refiners, beaters, PFI mills, kneaders, dispersers, etc., in which metal or blades and pulp fibers act around a rotating shaft, those that rely on friction between pulp fibers, high-pressure homogenizers, and ultra-high-pressure homogenizers. , nanomizers, various mills, and millstone grinders.

In addition, pretreatment may be performed as necessary prior to beating or, if necessary, dispersion treatment performed before beating. Pretreatment includes, for example, mixing, stirring, emulsification, and dispersion, and may be performed using a known device (eg, high-speed shear mixer).

In the present invention, cellulose fibers may be made into nanofibers. The surface area is increased in the nanofiberized portion, and antiviral, deodorant, and antibacterial functions can be improved. On the other hand, if the fibers are completely converted to nanofibers, the fibers will be completely disaggregated, and the yield will decrease when blended with pulp to produce, or they will not remain in the paper (no residue), and the effects of cellulose fibers will be lost. or decrease. Here, the term "nanofibers" refers to disentanglement of cellulose fibers to a fiber diameter of 100 nm or less. In order to form nanofibers, any known device similar to that used for beating can be used.

Hereinafter, the present invention will be described in more detail with specific examples, but the present invention is not limited to the following specific examples. In this specification, concentrations and the like are based on weight unless otherwise specified, and numerical ranges are described as including the endpoints.

Experiment 1. Production of copper ion-loaded oxidized cellulose fiber (Cu ion-loaded oxidized cellulose fiber)
EMPO (manufactured by Sigma Aldrich) 39 mg (0.05 mmol relative to 1 g of cellulose in absolute dry condition) and 514 mg of sodium bromide (1.0 mmol relative to 1 g of cellulose in absolute dry condition) were added to 500 ml of an aqueous solution, and the pulp was uniformly dispersed. Stir until done.
Then, an aqueous sodium hypochlorite solution was added to the reaction system so that the sodium hypochlorite concentration was 5.5 mmol/g, and the oxidation reaction was started at room temperature. The pH in the system decreased during the reaction, but was adjusted to pH 10 by successively adding 3M sodium hydroxide aqueous solution. The reaction was terminated when the sodium hypochlorite was consumed and the pH in the system stopped changing (time required for the oxidation reaction: about 90 minutes).
After the reaction mixture was filtered through a glass filter, washing with a sufficient amount of water and filtration were repeated twice to obtain water-impregnated oxidized cellulose fibers (solid content: 10% by mass, pulp yield: : 90%, carboxyl group content: 1.68 mmol/g).
Water was added to the obtained oxidized cellulose fibers to prepare a dispersion having a solid concentration of 2%, and the pH was adjusted to 9.0. Next, CuCl ₂ (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added with stirring so that the concentration with respect to 1 g of oxidized cellulose fibers was 1.0 mmol/g, and the oxidized cellulose fibers were further stirred for 30 minutes to add Cu ions to the oxidized cellulose fibers. was included.
Thereafter, washing with a sufficient amount of water and filtration were repeated twice to remove unreacted metal salts, thereby obtaining Cu ion-supporting oxidized cellulose fibers impregnated with water (solid content: 30% by mass). The content of metal ions in the resulting Cu ion-supporting oxidized cellulose fibers was 43.8 mg/g, and the Canadian Standard Freeness (CSF) of the Cu ion-supporting oxidized cellulose fibers was 500 ml.

Experiment 2. Production of antiviral sheet [sheet 1]
Deinked waste paper pulp derived from waste newspaper (manufactured by Nippon Paper Industries Co., Ltd., CSF: 300 ml) is used as the cellulose fiber, and the Cu ion-supporting oxidized cellulose fiber produced in Experiment 1 is 1% by weight of the entire cellulose fiber. was blended as follows. While stirring at 500 rpm using a three-one motor, 30% by weight (solid content) of light calcium carbonate, 0.7% by weight (solid content) of polyaluminum chloride, and 0.05% by weight with respect to 100% by weight of cellulose fiber. (solid content) of the paper strength improver was sequentially added to prepare a pulp slurry. A sheet having a basis weight of 60 g/m ² , a paper thickness of 120 μm, and an ash content of 14% was produced from the resulting pulp slurry using a circular handsheet machine.
[Sheet 2]
A size press liquid containing 5% by weight of oxidized starch (SK20, manufactured by Nippon Corn Starch Co., Ltd.) was prepared. This size press liquid was applied to both sides of sheet 1 and dried by a conventional method (coating amount: 1 g/m ² in total on both sides).
[Sheet 3]
On one side of the sheet 2, using an RI-I type printer (manufactured by Ishikawajima Sangyo Kikai Co., Ltd.), Vantean Echo ink (manufactured by Toyo Ink Co., Ltd.) is solidly printed so that the ink density immediately after printing is 1.0. did.
[Sheet 4]
A sheet was produced in the same manner as Sheet 1, except that the Cu ion-supporting oxidized cellulose fibers were blended in an amount of 3% by weight based on the total cellulose fibers.
[Sheet 5]
A sheet was produced in the same manner as Sheet 1, except that Cu ion-supporting oxidized cellulose fibers were blended in an amount of 5% by weight with respect to the total cellulose fibers.
[Sheet 6]
A sheet was produced in the same manner as Sheet 2, except that the Cu ion-supporting oxidized cellulose fibers were blended in an amount of 5% by weight based on the total cellulose fibers.
[Sheet 7]
A sheet was produced in the same manner as Sheet 3, except that Cu ion-supporting oxidized cellulose fibers were blended in an amount of 5% by weight with respect to the total cellulose fibers.
[Sheet 8]
LBKP (manufactured by Nippon Paper Industries Co., Ltd., CSF: 480 ml) was used as the cellulose fiber, and the Cu ion-supporting oxidized cellulose fiber produced in Experiment 1 was blended with the cellulose fiber so as to be 4% by weight of the entire cellulose fiber. To 100% by weight of cellulose fiber, 0.16% by weight of sizing agent, 1.50% by weight of aluminum sulfate, and 0.70% by weight of cationized starch were sequentially added to prepare a pulp slurry. From the obtained pulp slurry, paper is made using a paper machine at a speed of 250 m/min, and calendering is performed to obtain a paper having a basis weight of 71.0 g/m ² and a paper thickness of 105 μm.
sheet was manufactured.
[Sheet 9]
A sheet was produced in the same manner as Sheet 8, except that the Cu ion-supporting oxidized cellulose fibers were blended in an amount of 7% by weight with respect to the total cellulose fibers.
[Sheet 10]
A sheet was produced in the same manner as in Sheet 8, except that Cu ion-supporting oxidized cellulose fibers were blended in an amount of 10% by weight with respect to the total cellulose fibers.
[Sheet 11] (Comparative example)
A sheet was produced in the same manner as Sheet 1, except that the Cu ion-supporting oxidized cellulose fiber was not used.
[Sheet 12] (Comparative example)
A sheet was produced in the same manner as Sheet 8, except that Cu ion-supporting oxidized cellulose fibers were not used.
[Sheet 13] (Comparative example)
A sheet was produced in the same manner as Sheet 8, except that Cu ion-supporting oxidized cellulose fibers were blended in an amount of 1% by weight with respect to the total cellulose fibers.

Experiment 3. Evaluation of Antiviral Sheet The obtained antiviral sheet was evaluated for antiviral function and the like by the methods described below.
[Copper content]
The content (mg/g) of metal ions and metal particles per 1 g of the sheet was measured by ICP optical emission spectrometry (ICP-OES) according to the following procedure.
(1) Dry the measurement sample (50°C, 1 day) before measurement. (2) Weigh 0.1 g of the dried measurement sample and put it in a 50 ml beaker. (3) Add concentrated nitric acid. Take 10 ml with a whole pipette and add it to the beaker containing the sample for measurement to prepare a measurement sample solution (10-fold dilution).
(4) Leave to stand for 30 minutes, then pass through a syringe filter to remove (filter) fibers from the measurement sample solution (5) Take 1 ml of the filtered measurement sample solution with a micropipette and add 49 ml of distilled water. Add to tube (50-fold dilution)
(6) Close the lid of the test tube tightly and shake to stir (7) ICP-OES (manufactured by Agilent Technology, ICP-OES
5110) is used to measure (quantify) the content of metal ions and metal particles (8) From the quantification results (ppb) by ICP-OES, the content of metal ions and metal particles per 1 g of sheet (mg/ g) is calculated based on the following formula.
(Quantification result by ICP-OES (ppb) × 10 × 50) / (Weight of sample for measurement (g)
)×1000/1000000000
[Antiviral function]
The antiviral function test was performed according to JIS L 1922:2016, and the antiviral activity value (Mv) was calculated. The weight of the sheet subjected to the test was 0.4 g, and the following two types of test viruses were used.
・Influenza virus (H3N2, ATCC VR-1679)
・ Feline calicivirus (Strain: F-9 ATCC VR-782)

[Deodorizing function]
The deodorant function test was carried out by the SEK mark textile product certification standard (JEC301, Textile Evaluation Technology Council) with ammonia as the object and a test sample size of 100 cm ² . The deodorizing function was evaluated according to the following criteria.
◎ (very good): ammonia reduction rate is 80% or more ○ (good): ammonia reduction rate is 70% or more and less than 80% × (bad): ammonia reduction rate is less than 70%

上記の結果から明らかなように、本発明によれば、優れた抗ウイルス機能、消臭機能、抗菌機能を有する抗ウイルス性シートを製造することができた。
実験４
４－１．Ｃｕイオン担持酸化セルロース繊維の製造
針葉樹由来の漂白済み未叩解クラフトパルプ（白色度８５％）２７５ＢＤｋｇ（絶乾）をＴＥＭＰＯ（Ｓｉｇｍａ Ａｌｄｒｉｃｈ社製）１．０７ｋｇ（絶乾１ｇのセルロースに対し０．２５ｍｍｏｌ）と臭化ナトリウム２８．３ｋｇ（絶乾１ｇのセルロースに対し１．０ｍｍｏｌ）を溶解した水溶液５００ｍｌに加え、パルプが均一に分散するまで撹拌した。
次いで、次亜塩素酸ナトリウム水溶液を次亜塩素酸ナトリウムが５．２ｍｍｏｌ／ｇになるように反応系に添加し、室温にて酸化反応を開始した。反応中は系内のｐＨが低下するが、３Ｍ水酸化ナトリウム水溶液を逐次添加し、ｐＨ１０に調整した。次亜塩素酸ナトリウムを消費し、系内のｐＨが変化しなくなった時点で反応を終了した（酸化反応に要した時間：約９０分）。
反応後の混合物をスクリュープレスで脱水した後、十分な水の量による水洗、ろ過を２
回繰り返すことにより、水を含浸させた酸化セルロース繊維を得た（固形分：１０質量％、パルプ収率：９０％、カルボキシル基量：１．６８ｍｍｏｌ／ｇ）。
得られた酸化セルロース繊維に対し、水を加えて固形分濃度２％の分散液とし、ｐＨを９．０に調整した。次いで、ＣｕＣｌ_２（富士フイルム和光純薬）を加え、酸化セルロース繊維１ｇに対する濃度が１．０ｍｍｏｌ／ｇになるよう撹拌しながら加え、さらに３０分間撹拌することにより、酸化セルロース繊維にＣｕイオンを含有させた。
その後、十分な量の水による水洗、ろ過を２回繰り返すことにより、未反応の金属塩を除去し、水を含浸させたＣｕイオン担持酸化セルロース繊維を得た（固形分：３０質量％）。得られたＣｕイオン担持酸化セルロース繊維における金属イオンの含有量は４３．８ｍｇ／ｇであり、Ｃｕイオン担持酸化セルロース繊維のカナダ標準ろ水度（ＣＳＦ）は５００ｍｌであった。
４－２．Ｃｕイオン担持カルボキシメチル化セルロース繊維の製造
回転数を１００ｒｐｍに調節した二軸ニーダーに、水１３０部と、水酸化ナトリウム２０部を水１００部に溶解したものとを加え、広葉樹パルプ（日本製紙社製、ＬＢＫＰ）を１００℃６０分間乾燥した際の乾燥質量で１００部仕込んだ。３０℃で９０分間撹拌、混合しマーセル化セルロースを調製した。更に撹拌しつつイソプロパノール（ＩＰＡ）２３０部と、モノクロロ酢酸ナトリウム６０部を添加し、３０分間撹拌した後、７０℃に昇温して９０分間ＣＭ化反応をさせた。ＣＭ化反応時の反応媒中のＩＰＡの濃度は、５０％である。反応終了後、ｐＨ７になるまで酢酸で中和、含水メタノールで洗浄、脱液、乾燥、粉砕して、ＣＭ置換度が０．３４、セルロースＩ型の結晶化度が７０％、１％（ｗ／ｖ）水分散液とした際のＢ型粘度（ＢＬ型粘度計（東機産業社製）、２５℃、３０ｒｐｍ）が３８ｍＰａ・ｓのＣＭ化セルロース繊維を得た。また、銅イオンを含む水溶液として、硫酸銅５水和物（富士フイルム和光純薬社製）を水に溶解した１０％硫酸銅水溶液を調製した。
温度を２５℃に調整し、５００～６００ｒｐｍで攪拌している１０００ｇの水中に、１０ｇの上記ＣＭ化セルロース繊維（固形分９２．７％）を少量ずつ添加した。次に１ｇのＣＭ化セルロース繊維に対して１．００ｍｍｏｌに相当する硫酸銅となるように、送液ポンプを使用して１０％硫酸銅水溶液を添加した。添加終了後、３０分間撹拌を継続した後に、サンプリングした。
４－３．抗ウイルス性シートの製造
（１）サンプル４－１
セルロース繊維としてＬＢＫＰ（日本製紙、ＣＳＦ：４７０ｍｌ）を使用し、これにＣｕイオン担持酸化セルロース繊維をセルロース繊維全体に対して６重量％となるように配合した。そこに軽質炭酸カルシウムを紙中灰分５％となるように添加した。セルロース繊維１００重量％に対し、０．８０重量％のカチオン化澱粉を添加し、パルプスラリーを調製した。得られたパルプスラリーから、抄紙機を用いて速度５４０ｍ／ｍｉｎで抄造した。
酸化澱粉（日本コーンスターチ、ＳＫ２０）を１００重量質量部に対し、原塩を３．５重量質量部添加し、固形分濃度１１質量％に調製した表面処理液を調製し、ゲートロールコーター（ＧＲＣ）を用いて塗工した（両面塗布量：約１．６ｇ／ｍ^２）。乾燥後、カレンダー処理をし、坪量約８０ｇ／ｍ^２の紙を得た。
（２）サンプル４－２
セルロース繊維としてＬＢＫＰ（日本製紙、ＣＳＦ：４７０ｍｌ）を使用し、これにＣｕイオン担持酸化セルロース繊維をセルロース繊維全体に対して３重量％となるように配合した（軽質炭酸カルシウム無配合）。セルロース繊維１００重量％に対し、０．８０重量％のカチオン化澱粉を添加し、パルプスラリーを調製した。得られたパルプスラリーから、抄紙機を用いて速度５４０ｍ／ｍｉｎで抄造した。
次いで、酸化澱粉（日本コーンスターチ、ＳＫ２０）を１００重量部に対し、アニオン性サイズ剤（ハリマ化成）を５．６部、原塩を３．５重量部添加し、固形分濃度１１質量％に調製した表面処理液を調製し、ゲートロールコーター（ＧＲＣ）を用いて塗工した（
両面塗布量：約１．６ｇ／ｍ^２）。乾燥後、カレンダー処理をし、坪量約８０ｇ／ｍ^２の紙を得た。
（３）サンプル４－３
タルクを紙中灰分５％となるように添加した以外は、サンプル４－２と同様にして抄造した。
（４）サンプル４－４
セルロース繊維としてＬＢＫＰ（日本製紙、ＣＳＦ：４８０ｍｌ）：ＮＢＫＰ（日本製紙、ＣＳＦ：５９０ｍｌ）＝７２：２４となるように混合し、これにＣｕイオン担持酸化セルロース繊維をセルロース繊維全体に対して４重量％となるように配合した。セルロース繊維１００重量％に対し、０．１６重量％のロジン系サイズ剤（荒川化学工業、サイズパインＮ７９６）、１．５０重量％の硫酸バンド（硫酸アルミニウム）、０．７０重量％のカチオン化澱粉を順次添加し、パルプスラリーを調製した。得られたパルプスラリーから、抄紙機を用いて速度２５０ｍ／ｍｉｎで抄紙し、カレンダー処理を行い、シートを製造した（坪量：７１．０ｇ／ｍ^２、紙厚：１０５μｍ）。
（５）サンプル４－５（比較例）
Ｃｕイオン担持酸化セルロース繊維を配合しなかった以外は、サンプル４－２と同様にして抄造した。
（６）サンプル４－６
セルロース繊維としてＬＢＫＰ（日本製紙、ＣＳＦ：４７０ｍｌ）を使用し、これにＣｕイオン担持酸化セルロース繊維をセルロース繊維全体に対して３重量％となるように配合した（軽質炭酸カルシウム無配合）。セルロース繊維１００重量％に対し、０．８０重量％のカチオン化澱粉、０．１重量％のＡＫＤ系サイズ剤（星光ＰＭＣ、ＡＤ１６１４）を添加し、パルプスラリーを調製した。得られたパルプスラリーから、抄紙機を用いて速度５４０ｍ／ｍｉｎで抄造した。
次いで、酸化澱粉（日本コーンスターチ、ＳＫ２０）を１００重量部に対し、アニオン性サイズ剤（ハリマ化成）を５．６部、原塩を３．５重量部添加し、固形分濃度１１質量％に調製した表面処理液を調製し、ゲートロールコーター（ＧＲＣ）を用いて塗工した（両面塗布量：約１．６ｇ／ｍ^２）。乾燥後、カレンダー処理をし、坪量約１８０ｇ／ｍ^２の紙を得た。
（７）サンプル４－７（比較例）
Ｃｕイオン担持酸化セルロース繊維を配合しなかった以外はサンプル４－６と同様に抄造した。
（８）サンプル４－８（ＣＭ化、実施例）
Ｃｕイオン担持酸化セルロース繊維をＣｕイオン担持カルボキシメチル化セルロース繊維とした以外は、サンプル４－２と同様にして抄造した
４－４．抗ウイルス性の評価
得られたシートについて、実験１と同様にして抗ウイルス機能などを評価した。また、金属溶出量などについては、下記のように評価した。
［坪量］ ＪＩＳ Ｐ８１２４に準じて測定した。
［紙厚］ ＪＩＳ Ｐ８１１８に準じて測定した。
［ＩＳＯ白色度］ ＪＩＳ Ｐ８１４８に準じて、色差計（村上色彩、ＣＭＳ－３５ＳＰＸ）を用いて測定した。
［ＩＳＯ不透明度］ ＪＩＳ Ｐ８１４９に準じて測定した。
［色相］ ＪＩＳ Ｐ８１５０に準じて測定した。
［ステキヒトサイズ度］ ＪＩＳ Ｐ８１２２に準じて測定した。
［紙面ｐＨ］
ｐＨメーター（HORIBA製、F-24型）に表面測定用不ガラス電極（HORIBA製、フラット型ｐＨ複合電極6261-10C）を取り付け、下記の手順にて測定した。
（１） 電極を純水で洗浄する
（２） 電極の先端に純水1滴をつける
（３） 測定試料の表面に電極先端を接し、１分後の値を評価する
（４） （１）～（３）を５回繰り返し、その平均値を紙面ｐＨとして記録する
［金属溶出量］
銅について、シート０．８ｇあたりの金属イオンおよび金属粒子の超純水１００ｍｌ中への溶出量を、ＩＣＰ発光分光分析（ＩＣＰ－ＯＥＳ）により、下記の手順によって測定した。
（１） 測定の前に測定用試料を乾燥（５０℃、1日）させておく
（２） ３００ｍｌ容のカップに超純水を入れる（３０℃、１００ｍｌ）
（３） 乾燥させた測定用試料０．８ｇを（２）のカップに入れ蓋する
（４） ３０分間、３０℃で静置してから、シリンジフィルターに通して測定サンプル液から繊維分を除去（ろ過）する
（５） ろ過した測定サンプル液４９ｍｌを試験管に入れ、マイクロピペットで濃硝酸を１ｍｌ加える
（６） 試験管の蓋をしっかり閉め、振って攪拌する
（７） ＩＣＰ－ＯＥＳ（Ａｇｉｌｅｎｔ Ｔｅｃｈｎｏｌｏｇｙ社製、ＩＣＰ－ＯＥＳ
５１１０）を使用して、金属イオンおよび金属粒子の含有量を測定（定量）する
（８） ＩＣＰ－ＯＥＳによる定量結果から、シート０．８ｇあたりの金属イオンおよび金属粒子の超純水１００ｍｌ中への溶出量を下式に基づいて算出する。
ＩＣＰ－ＯＥＳによる定量結果（ｐｐｂ）×５０／４９
［消臭機能］
消臭機能試験は、ＳＥＫマーク繊維製品認証基準（ＪＥＣ３０１、繊維評価技術協議会）の方法にて、硫化水素を対象として、試験資料サイズ１００ｃｍ^２で実施した。以下の基準で消臭機能を評価した。
◎（非常に良い）： 硫化水素の減少率が８０％以上
○（良い） ： 硫化水素の減少率が７０％以上８０％未満
×（悪い） ： 硫化水素の減少率が７０％未満
［抗菌機能］
ＪＩＳ Ｌ１９０２「繊維製品の抗菌性試験方法及び抗菌効果」に従い、ハロー法による定性試験を実施した。具体的には、大腸菌および黄色ブドウ球菌を含んだ寒天培地を作製し、その上に抗ウイルス性シートの５ｃｍ×５ｃｍの試験片を載せ、３７℃で１７時間培養後、試料の周りにできた試験菌の「生育阻止帯」の有無を確認した。以下の基準で抗菌機能を評価した。
○：生育阻止帯が認められ抗菌機能を有する。
×：生育阻止帯が認められず、抗菌機能を有さない。

上記の結果から明らかなように、本発明によれば、優れた抗ウイルス機能、消臭機能、
抗菌機能を有する抗ウイルス性シートを製造することができた。
[Antibacterial function]
A qualitative test was carried out by the halo method in accordance with JIS L1902 "Antibacterial test method and antibacterial effect of textile products". Specifically, an agar medium containing E. coli was prepared, a 5 cm x 5 cm test piece of an antiviral sheet was placed on it, and after culturing at 37 ° C. for 17 hours, the test bacteria formed around the sample. The presence or absence of growth inhibition zone” was confirmed. The antibacterial function was evaluated according to the following criteria.
◯: A zone of inhibition of growth is observed and has an antibacterial function.
x: No growth inhibition zone was observed, and no antibacterial function was observed.

As is clear from the above results, according to the present invention, an antiviral sheet having excellent antiviral, deodorant and antibacterial functions could be produced.
Experiment 4
4-1. Production of Cu ion-supporting oxidized cellulose fiber 275 BD kg (absolutely dry) of bleached unbeaten kraft pulp (whiteness 85%) derived from softwood was mixed with 1.07 kg of TEMPO (manufactured by Sigma Aldrich) (0.25 mmol per 1 g of absolute dry cellulose). ) and 28.3 kg of sodium bromide (1.0 mmol per 1 g of absolute dry cellulose) were added to 500 ml of an aqueous solution and stirred until the pulp was uniformly dispersed.
Then, an aqueous sodium hypochlorite solution was added to the reaction system so that sodium hypochlorite was 5.2 mmol/g, and an oxidation reaction was initiated at room temperature. The pH in the system decreased during the reaction, but was adjusted to pH 10 by successively adding 3M sodium hydroxide aqueous solution. The reaction was terminated when the sodium hypochlorite was consumed and the pH in the system stopped changing (time required for the oxidation reaction: about 90 minutes).
After the reaction mixture is dehydrated with a screw press, it is washed with a sufficient amount of water and filtered for 2 times.
By repeating the process several times, oxidized cellulose fibers impregnated with water were obtained (solid content: 10% by mass, pulp yield: 90%, amount of carboxyl groups: 1.68 mmol/g).
Water was added to the obtained oxidized cellulose fibers to prepare a dispersion having a solid concentration of 2%, and the pH was adjusted to 9.0. Next, CuCl ₂ (Fuji Film Wako Pure Chemical Industries, Ltd.) was added with stirring so that the concentration with respect to 1 g of oxidized cellulose fibers was 1.0 mmol/g, and the oxidized cellulose fibers were further stirred for 30 minutes to add Cu ions to the oxidized cellulose fibers. let me
Thereafter, washing with a sufficient amount of water and filtration were repeated twice to remove unreacted metal salts, thereby obtaining Cu ion-supporting oxidized cellulose fibers impregnated with water (solid content: 30% by mass). The content of metal ions in the resulting Cu ion-supporting oxidized cellulose fibers was 43.8 mg/g, and the Canadian Standard Freeness (CSF) of the Cu ion-supporting oxidized cellulose fibers was 500 ml.
4-2. Production of Cu ion-carrying carboxymethylated cellulose fibers Add 130 parts of water and 20 parts of sodium hydroxide dissolved in 100 parts of water to a twin-screw kneader whose rotation speed is adjusted to 100 rpm, and hardwood pulp (Nippon Paper Industries Co., Ltd. LBKP) was charged at 100 parts by dry mass when dried at 100° C. for 60 minutes. The mixture was stirred and mixed at 30°C for 90 minutes to prepare mercerized cellulose. Further, while stirring, 230 parts of isopropanol (IPA) and 60 parts of sodium monochloroacetate were added, and after stirring for 30 minutes, the temperature was raised to 70° C. and a CM conversion reaction was carried out for 90 minutes. The concentration of IPA in the reaction medium during the CM conversion reaction is 50%. After completion of the reaction, the reaction was neutralized with acetic acid until the pH reached 7, washed with water-containing methanol, deliquored, dried, and pulverized. /v) A CM-modified cellulose fiber having a B-type viscosity (BL-type viscometer (manufactured by Toki Sangyo Co., Ltd.), 25° C., 30 rpm) of 38 mPa·s when made into an aqueous dispersion was obtained. As an aqueous solution containing copper ions, a 10% copper sulfate aqueous solution was prepared by dissolving copper sulfate pentahydrate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) in water.
10 g of the CM-modified cellulose fiber (solid content 92.7%) was added little by little to 1000 g of water whose temperature was adjusted to 25° C. and stirred at 500-600 rpm. Next, a 10% copper sulfate aqueous solution was added using a liquid feed pump so that copper sulfate corresponding to 1.00 mmol per 1 g of CM cellulose fiber was added. After the addition was completed, stirring was continued for 30 minutes before sampling.
4-3. Production of antiviral sheet (1) Sample 4-1
LBKP (Nippon Paper Industries Co., Ltd., CSF: 470 ml) was used as cellulose fibers, and Cu ion-supporting oxidized cellulose fibers were added to the cellulose fibers in an amount of 6% by weight based on the total cellulose fibers. Light calcium carbonate was added thereto so that the ash content in the paper was 5%. A pulp slurry was prepared by adding 0.80% by weight of cationized starch to 100% by weight of cellulose fiber. A paper machine was used to make paper from the resulting pulp slurry at a speed of 540 m/min.
A surface treatment liquid was prepared by adding 3.5 parts by weight of raw salt to 100 parts by weight of oxidized starch (Japanese cornstarch, SK20) to a solid content concentration of 11% by weight, and using a gate roll coater (GRC). (Coating amount on both sides: about 1.6 g/m ² ). After drying, it was calendered to obtain paper with a basis weight of about 80 g/m ² .
(2) Sample 4-2
LBKP (Nippon Paper Industries Co., Ltd., CSF: 470 ml) was used as cellulose fibers, and Cu ion-supporting oxidized cellulose fibers were blended in 3% by weight of the total cellulose fibers (no light calcium carbonate blended). A pulp slurry was prepared by adding 0.80% by weight of cationized starch to 100% by weight of cellulose fiber. A paper machine was used to make paper from the resulting pulp slurry at a speed of 540 m/min.
Next, 5.6 parts of an anionic sizing agent (Harima Kasei) and 3.5 parts of raw salt are added to 100 parts by weight of oxidized starch (Japanese corn starch, SK20) to prepare a solid content concentration of 11% by mass. A surface treatment liquid was prepared and coated using a gate roll coater (GRC) (
Coating amount on both sides: about 1.6 g/m ² ). After drying, it was calendered to obtain paper with a basis weight of about 80 g/m ² .
(3) Sample 4-3
Paper was made in the same manner as Sample 4-2, except that talc was added so that the ash content in the paper was 5%.
(4) Sample 4-4
LBKP (Nippon Paper Industries, CSF: 480 ml) and NBKP (Nippon Paper Industries, CSF: 590 ml) as cellulose fibers were mixed in a ratio of 72:24, and Cu ion-supporting oxidized cellulose fibers were added to the entire cellulose fibers by 4 weight. %. 0.16% by weight of rosin-based sizing agent (Arakawa Chemical Industries, Sizepine N796), 1.50% by weight of aluminum sulfate (aluminum sulfate), and 0.70% by weight of cationized starch with respect to 100% by weight of cellulose fiber were sequentially added to prepare a pulp slurry. The obtained pulp slurry was made into a sheet (basis weight: 71.0 g/m ² , paper thickness: 105 μm) by using a paper machine at a speed of 250 m/min and subjected to calendering.
(5) Sample 4-5 (comparative example)
Paper was made in the same manner as Sample 4-2, except that the Cu ion-supporting oxidized cellulose fiber was not blended.
(6) Sample 4-6
LBKP (Nippon Paper Industries Co., Ltd., CSF: 470 ml) was used as cellulose fibers, and Cu ion-supporting oxidized cellulose fibers were blended in 3% by weight of the total cellulose fibers (no light calcium carbonate blended). A pulp slurry was prepared by adding 0.80% by weight of cationized starch and 0.1% by weight of an AKD-based sizing agent (Seiko PMC, AD1614) to 100% by weight of cellulose fiber. A paper machine was used to make paper from the resulting pulp slurry at a speed of 540 m/min.
Next, 5.6 parts of an anionic sizing agent (Harima Kasei) and 3.5 parts of raw salt are added to 100 parts by weight of oxidized starch (Japanese corn starch, SK20) to prepare a solid content concentration of 11% by mass. A surface treatment liquid was prepared and coated using a gate roll coater (GRC) (coating amount on both sides: about 1.6 g/m ² ). After drying, it was calendered to obtain paper with a basis weight of about 180 g/m ² .
(7) Sample 4-7 (comparative example)
Paper was made in the same manner as Sample 4-6, except that the Cu ion-supporting oxidized cellulose fiber was not blended.
(8) Sample 4-8 (commercialization, example)
Paper was made in the same manner as in Sample 4-2, except that Cu ion-supporting oxidized cellulose fibers were replaced with Cu ion-supporting carboxymethylated cellulose fibers. 4-4. Evaluation of Antiviral Properties The antiviral function and the like of the obtained sheet were evaluated in the same manner as in Experiment 1. In addition, the metal elution amount and the like were evaluated as follows.
[Basis Weight] Measured according to JIS P8124.
[Paper Thickness] Measured according to JIS P8118.
[ISO Whiteness] Measured according to JIS P8148 using a color difference meter (Murakami Color Co., Ltd., CMS-35SPX).
[ISO Opacity] Measured according to JIS P8149.
[Hue] Measured according to JIS P8150.
[Steckigt Sizing Degree] Measured according to JIS P8122.
[Paper surface pH]
A non-glass electrode for surface measurement (flat pH composite electrode 6261-10C, manufactured by HORIBA) was attached to a pH meter (model F-24, manufactured by HORIBA), and the pH was measured according to the following procedure.
(1) Wash the electrode with pure water (2) Put a drop of pure water on the tip of the electrode (3) Touch the tip of the electrode to the surface of the measurement sample and evaluate the value after 1 minute (4) (1) Repeat ~ (3) 5 times and record the average value as the paper surface pH [metal elution amount]
Regarding copper, the amounts of metal ions and metal particles eluted into 100 ml of ultrapure water per 0.8 g of the sheet were measured by ICP optical emission spectrometry (ICP-OES) according to the following procedure.
(1) Dry the measurement sample (50°C, 1 day) before measurement (2) Put ultrapure water in a 300ml cup (30°C, 100ml)
(3) Put 0.8 g of the dried sample for measurement into the cup of (2) and cover it. (4) Allow to stand at 30°C for 30 minutes, then pass it through a syringe filter to remove fibers from the measurement sample solution. (Filtration) (5) Put 49 ml of the filtered measurement sample solution into a test tube and add 1 ml of concentrated nitric acid with a micropipette (6) Close the lid of the test tube tightly and shake to stir (7) ICP-OES (Agilent ICP-OES manufactured by Technology
5110) is used to measure (quantify) the content of metal ions and metal particles (8) From the results of quantification by ICP-OES, metal ions and metal particles per 0.8 g of sheet into 100 ml of ultrapure water Calculate the amount of elution of based on the following formula.
Quantification result by ICP-OES (ppb) × 50/49
[Deodorizing function]
The deodorizing function test was carried out using a test sample size of 100 cm ² for hydrogen sulfide according to the SEK mark textile product certification standard (JEC301, Textile Evaluation Technology Council). The deodorizing function was evaluated according to the following criteria.
◎ (Very good): Reduction rate of hydrogen sulfide is 80% or more ○ (Good): Reduction rate of hydrogen sulfide is 70% or more and less than 80% × (Bad): Reduction rate of hydrogen sulfide is less than 70% [Antibacterial function ]
A qualitative test was carried out by the halo method in accordance with JIS L1902 "Antibacterial test method and antibacterial effect of textile products". Specifically, an agar medium containing E. coli and Staphylococcus aureus was prepared, a 5 cm x 5 cm test piece of an antiviral sheet was placed on it, and after culturing at 37 ° C. for 17 hours, a The presence or absence of a "growth inhibition zone" of the test bacteria was confirmed. The antibacterial function was evaluated according to the following criteria.
◯: A zone of inhibition of growth is observed and has an antibacterial function.
x: No growth inhibition zone was observed, and no antibacterial function was observed.

As is clear from the above results, according to the present invention, excellent antiviral function, deodorant function,
An antiviral sheet having an antibacterial function could be produced.

Claims (1)

The invention described in the specification.