Paper yarn base paper

Abstract

To provide paper yarn base paper that has antiviral properties as well as deodorant and antibacterial properties, and has excellent twisting suitability.SOLUTION: The paper yarn base paper includes pulp and metal-containing anionic modified cellulosic fibers containing one or more metal ions and / or metal particles selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn and Cu, with a basis weight of 5 to 40 g / m2, a longitudinal tensile strength of 12 N / 15 mm or more, a longitudinal wet tensile strength of 3.0 N / 15 mm or more, and a transverse to longitudinal ratio of tensile strength and wet tensile strength of 25% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a base paper for paper yarns (yarns made of paper) for manufacturing paper yarns.

Background Art

[0002] Various fibers are used for fabrics. For example, there are chemical synthetic fibers such as polyester, nylon, and acrylic, natural fibers such as cotton and wool, and blended fibers obtained by mixing and twisting two or more of natural fibers and synthetic fibers. Since it is easy to impart various functions to synthetic fibers as compared with natural fibers, synthetic fibers are currently the mainstream. Although synthetic fibers are excellent materials, a large amount of extremely small microfibers are generated when washed in a washing machine. Since this microfiber flows out into rivers and the ocean as washing wastewater, there are concerns about its impact on the environment as a type of microplastic. Therefore, attention has been focused on natural materials that decompose in nature, but it is difficult to impart high functionality like synthetic fibers. For example, Patent Document 1 discloses a twisted yarn carrying a metal having a deodorizing effect, but the twist yarn suitability and the like were insufficient.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a base paper for paper yarns that has deodorizing, antibacterial, and antiviral properties and is excellent in twist yarn suitability.

Means for Solving the Problems

[0005] Means for solving the problems of the present invention are as follows. [1] It includes pulp and metal-containing anionic modified cellulose fibers containing one or more metal ions and / or metal particles selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu. with a basis weight of 5 to 40 g / m 2 , a longitudinal tensile strength of 12 N / 15 mm or more, a longitudinal wet tensile strength of 3.0 N / 15 mm or more, and a transverse / longitudinal ratio of tensile strength and wet tensile strength of 25% or less. The base paper for paper yarn is characterized by this. [2] The base paper for paper yarn according to [1], wherein the metal-containing anionic modified cellulose fibers are Cu-containing anionic modified cellulose fibers. [3] The base paper for paper yarn according to [1] or [2], wherein the Cu content is 0.25% by mass or more. [4] The base paper for paper yarn according to any one of [1] to [3], wherein the pulp contains at least one of softwood pulp and hemp pulp. [5] The base paper for paper yarn according to any one of [1] to [4], characterized by containing an amphoteric dry paper strength agent and a wet paper strength agent. [6] The base paper for paper yarn according to any one of [1] to [5], wherein the content of the water-soluble aluminum salt is 0.3% by mass or less based on the total of the pulp and the metal-containing anionic modified cellulose fibers. [Advantages of the Invention]

[0006] According to the present invention, it is possible to provide a base paper for paper yarn that has deodorizing, antibacterial, and antiviral properties and excellent twistability. [Embodiments for Carrying Out the Invention]

[0007] (Base paper for paper yarn) The base paper for paper yarn of the present invention includes pulp and metal-containing anionic modified cellulose fibers containing one or more metal ions and / or metal particles selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu. with a basis weight of 5 to 40 g / m 2, the longitudinal tensile strength is 12 N / 15 mm or more, the longitudinal wet tensile strength is 3.0 N / 15 mm or more, and the horizontal / longitudinal ratio of the tensile strength and the wet tensile strength is 25% or less. In this specification, the description of "A to B" (A and B are numerical values or ratios) means a numerical range including both ends.

[0008] The basis weight of the base paper for paper yarn of the present invention is 5 to 40 g / m 2 is. When the basis weight of the base paper for paper yarn is less than 5 g / m 2 , the base paper for paper yarn does not have sufficient strength, so yarn breakage frequently occurs during twisting. On the other hand, when the basis weight exceeds 40 g / m 2 , the paper yarn obtained by twisting the base paper for paper yarn becomes hard and difficult to handle. The basis weight of the base paper for paper yarn is preferably 7 g / m 2 or more, more preferably 10 g / m 2 or more. Also, it is preferably 35 g / m 2 or less, more preferably 20 g / m 2 or less, and even more preferably 18 g / m 2 or less.

[0009] The base paper for paper yarn of the present invention has a longitudinal tensile strength of 12 N / 15 mm or more and a longitudinal wet tensile strength of 3.0 N / 15 mm or more. The paper yarn is manufactured by thinly slitting the base paper for paper yarn into a tape shape and twisting it. By setting the longitudinal tensile strength of the base paper for paper yarn to 12 N / 15 mm or more and the longitudinal wet tensile strength to 3.0 N / 15 mm or more, it is possible to suppress the occurrence of yarn breakage in the twisting process and the dyeing process after twisting, and a high effect on the washability when made into a fabric is exhibited. The longitudinal tensile strength of the base paper for paper yarn of the present invention is preferably 20 N / 15 mm or more, more preferably 25 N / 15 mm. Also, the longitudinal wet tensile strength of the base paper for paper yarn of the present invention is preferably 5.0 N / 15 mm or more, more preferably 8.0 N / 15 mm or more. The base paper for paper yarn of the present invention has a horizontal / longitudinal ratio of the tensile strength and the wet tensile strength of 25% or less. By satisfying this tensile strength ratio, it is possible to suppress a decrease in workability, paper breakage, and wear of the slitting blade during processing into a tape shape, and to obtain a twisted yarn having sufficient strength.

[0010] (Metal-containing anionic modified cellulose fiber) The metal-containing anionic modified cellulose fiber of the present invention contains one or more metal ions and / or metal particles selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu. In the metal-containing anionic modified cellulose fiber, metal ions are ionically bonded to the cellulose fiber having an anionic group. By using the anionic modified cellulose fiber, the metal ions are chemically bonded and difficult to desorb, and the anionic group improves the paper strength during wet and dry states, so that it can have sufficient strength as a base paper for paper yarns. Examples of the anionic modified cellulose fiber include oxidized cellulose, etherified cellulose (such as carboxymethylated cellulose), esterified cellulose (such as phosphoric acid esterified cellulose), sulfonated cellulose, and the like.

[0011] In the present invention, natural cellulose is preferably used as the raw material of the metal-containing anionic modified cellulose fiber. Examples of natural cellulose include various wood pulps obtained from coniferous trees and broad-leaved trees, kenaf, bagasse, straw, bamboo, cotton, non-wood pulps obtained from seaweeds, cellulose obtained from jellyfish, cellulose produced by microorganisms, and the like. The metal-containing anionic modified cellulose fiber preferably has a Canadian standard drainage degree of 200 to 700 ml, a fiber length of 0.5 to 2.5 mm, and a fiber diameter of 10 to 40 μm. Within this range, it is difficult to break the paper during papermaking. In this specification, the average fiber length and the average fiber width respectively mean the length-weighted average fiber length and the length-weighted average fiber width. For example, they can be measured by observing the fibers using an image analysis device such as a fiber tester manufactured by ABB Ltd., a fractionator manufactured by Valmet Corporation, FS5 manufactured by Valmet Corporation, Morfi manufactured by Voith Turbo GmbH, an optical microscope, an electron microscope, or the like.

[0012] Regarding the amount of anionic groups in the cellulose fiber having an anionic group, in the cellulose fiber having a carboxyl group, a carboxylate group, a phosphate group, or a sulfonic acid group, it can be measured by the following method. (Quantification of the amount of anionic groups 1) Prepare 60 ml of a 0.5% by mass slurry (aqueous dispersion) of a cellulose-based fiber sample having an acid group, add 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5, and then add a 0.05 N sodium hydroxide aqueous solution dropwise until the pH reaches 11, and measure the electrical conductivity. Calculate from the amount of sodium hydroxide (a) consumed in the neutralization stage of the weak acid where the change in electrical conductivity is gentle using the following formula. Amount of anionic groups [mmol / g] of cellulose-based fibers having an acid group = a [ml] × 0.05 / mass of oxidized cellulose-based fibers having an acid group [g] / x (x: value corresponding to the valence of the acid group (carboxyl group, carboxylate group, sulfonic acid group: 1, phosphate group: 2))

[0013] When quantifying the amount of anionic groups by carboxyalkylation treatment, use the following method. (Quantification of the amount of anionic groups 2) Precisely weigh about 2.0 g of carboxyalkylated cellulose fiber (absolutely dry) and place it in a 300 mL Erlenmeyer flask with a stopper. Add 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitric acid to 1000 mL of nitric acid methanol, shake for 3 hours to convert the carboxyalkyl cellulose salt (CM cellulose) to hydrogen-type CM cellulose. Precisely weigh 1.5 - 2.0 g of hydrogen-type CM cellulose (absolutely dry) and place it in a 300 mL Erlenmeyer flask with a stopper. Moisten the hydrogen-type CM cellulose with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. Use phenolphthalein as an indicator and back-titrate the excess NaOH with 0.1 N H2SO4. The degree of carboxyalkyl substitution (DS) is calculated by the following formula. A = [(100 × F’ - (0.1 N H2SO4) (mL) × F) × 0.1] / (absolute dry mass (g) of hydrogen-type carboxyalkylated cellulose) DS = 0.162 × A / (1 - 0.058 × A) A: Amount of 1 N NaOH (mL) required for neutralization of 1 g of hydrogen-type carboxyalkylated cellulose F’: Factor of 0.1 N NaOH Factor of H2SO4 with F: 0.1N

[0014] The amount of anionic groups in the anionic group-containing cellulose fiber is preferably 0.01 to 3.0 mmol / g. When the amount of acid groups is less than 0.01 mmol / g, in the step of supporting metal ions described below, the amount of metal ions present on the surface of the cellulose fiber may not be sufficient, and the deodorizing, antibacterial, and antiviral functions may be inferior. On the other hand, when the amount of acid groups exceeds 3.0 mmol / g, cellulose cleavage is likely to occur as a side reaction during the oxidation reaction, and the yield may decrease.

[0015] The metal-containing anionic modified cellulose fiber can be produced by chemically modifying a general cellulose fiber as follows to introduce an anionic group into the glucose unit on the surface, and then further supporting metal ions and / or metal particles. Hereinafter, the method of introducing an anionic group into the glucose unit on the surface of the cellulose fiber and the method of supporting metal ions and / or metal particles thereafter will be described respectively.

[0016] <Oxidized cellulose> Cellulose has three hydroxyl groups per glucose unit and can be subjected to various chemical modification treatments. Oxidized cellulose is a modification that introduces a carboxyl group or a carboxylate group into at least a part of the cellulose fiber in the process described below. Here, in this specification, the carboxyl group refers to a group represented by -COOH, and the carboxylate group refers to -COO - refers to a group represented by, and the counter ion of the carboxylate group is not particularly limited. Also, the carboxyl group or the carboxylate group together is also referred to as an "acid group".

[0017] The method of modification for introducing a carboxyl group or a carboxylate group is not particularly limited as long as the modified cellulose fiber contains a carboxyl group or a carboxylate group. These will be described in detail below. (Oxidation of Cellulosic Fibers) In the present invention, the method for oxidizing cellulosic fibers is not particularly limited, and known methods can be used. As an example, there is a method of oxidizing a cellulose raw material in water using an oxidizing agent in the presence of a substance selected from the group consisting of N-oxyl compounds, bromides, iodides, and 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, and a group selected from the group consisting of an aldehyde group, a carboxyl group, and a carboxylate group is generated. The concentration of the cellulose raw material during the reaction is not particularly limited, but is preferably 5% by mass or less.

[0018] The N-oxyl compound refers to a compound capable of generating a nitroxyl radical. Examples of the nitroxyl radical include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). As the N-oxyl compound, any compound can be used as long as it promotes the target oxidation reaction. The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount capable of oxidizing the cellulosic fibers. For example, for 1 g of absolutely dry cellulose, 0.01 mmol or more is preferable, and 0.02 mmol or more is more preferable. 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 with respect to 1 g of absolutely dry cellulose.

[0019] A bromide is a compound containing bromine, and examples thereof include alkali metal bromides that can dissociate and ionize in water, such as sodium bromide. An iodide is a compound containing iodine, and examples thereof include alkali metal iodides. The amount of the bromide or iodide used may be selected within a range that can promote the oxidation reaction. The total amount of the bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, per 1 g of absolutely dry cellulose. The upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, still more preferably 5 mmol or less. Therefore, the total amount of the bromide and iodide is preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, still more preferably 0.5 to 5 mmol, per 1 g of absolutely dry cellulose.

[0020] The oxidizing agent is not particularly limited, and examples thereof include halogens, hypohalous acids, halous acids, perhalic acids, their salts, halogen oxides, peroxides, etc. In particular, hypohalous acids or their salts are preferred because they are inexpensive and have a low environmental impact, more preferably hypochlorous acid or its salt, and still more preferably sodium hypochlorite. The amount of the oxidizing agent used is preferably 0.1 mmol or more, more preferably 1 mmol or more, still more preferably 3 mmol or more, per 1 g of absolutely dry cellulose. The upper limit is preferably 500 mmol or less, more preferably 50 mmol or less, still more preferably 25 mmol or less. When using an N-oxyl compound, the amount of the oxidizing agent used is preferably 1 mol or more per 1 mol of the N-oxyl compound, and the upper limit is preferably 40 mol. Therefore, the amount of the oxidizing agent used is preferably 1 to 40 mol per 1 mol of the N-oxyl compound.

[0021] Conditions such as the pH and temperature during the oxidation reaction are not particularly limited. Generally, 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 lower, more preferably 11 or lower. Therefore, the pH of the reaction solution is preferably about 8 to 12, more preferably about 10 to 11. Generally, as the oxidation reaction proceeds, carboxyl groups are generated in the cellulose, so the pH of the reaction solution tends to decrease. Therefore, in order to efficiently proceed the oxidation reaction, 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. The reaction medium during oxidation is preferably water for reasons such as ease of handling and low likelihood of side reactions.

[0022] The reaction time for oxidation can be appropriately set according to the degree of progress of oxidation, and is usually 0.5 hours or more. 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. The oxidation may be carried out in two or more stages. For example, the oxidized cellulose obtained by filtration after the completion of the first-stage reaction is oxidized again under the same or different reaction conditions, so that it can be efficiently oxidized without being inhibited by the sodium chloride by-produced in the first-stage reaction. Another example of the oxidation method is the method of oxidizing by ozone treatment. By this oxidation reaction, at least the hydroxyl groups at the 2-position and 6-position of the glucopyranose ring constituting the cellulose are oxidized, and the decomposition of the cellulose chain occurs.

[0023] The ozone treatment is usually carried out by bringing a gas containing ozone into contact with the cellulose raw material. The ozone concentration in the gas is preferably 50 g / m 3 or higher. The upper limit is preferably 250 g / m 3 or lower, more preferably 220 g / m 3 or lower. Therefore, the ozone concentration in the gas is preferably 50 to 250 g / m 3 and more preferably 50 to 220 g / m 3 . The ozone addition amount is preferably 0.1% by mass or more, more preferably 5% by mass or more, based on 100% by mass of the solid content of the cellulose raw material. The upper limit is usually 30% by mass or less. Therefore, the ozone addition amount is preferably 0.1 - 30% by mass, more preferably 5 - 30% by mass, based on 100% by mass 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 lower. Therefore, the ozone treatment temperature is preferably 0 - 50°C, more preferably 20 - 50°C. The ozone treatment time is usually 1 minute or more, preferably 30 minutes or more. The upper limit is usually 360 minutes or less. Therefore, the ozone treatment time is usually about 1 - 360 minutes, preferably about 30 - 360 minutes. When the ozone treatment conditions are within the above range, it is possible to prevent the cellulose from being excessively oxidized and decomposed, and the yield of oxidized cellulose is good.

[0024] For the product obtained after ozone treatment, further post-oxidation treatment may be performed using an oxidizing agent. The oxidizing agent used for the post-oxidation treatment is not particularly limited, and examples include chlorine-based compounds such as chlorine dioxide and sodium chlorite; oxygen, hydrogen peroxide, persulfuric acid, peracetic acid, etc. Examples of the method for the post-oxidation treatment include 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.

[0025] The amounts of carboxyl groups, carboxylate groups, and aldehyde groups contained in the oxidized cellulose-based fibers can be adjusted by controlling oxidation conditions such as the addition amount of the oxidizing agent and the reaction time.

[0026] (Etherification of Cellulose-Based Fibers) As for the etherification, any method may be used as long as the functional group after the reaction contains a carboxyl group or a carboxylate group for the convenience of introducing metal ions into the cellulose-based fiber in the subsequent process, and known methods can be used. Examples include carboxymethyl (etherification), carboxyethyl (etherification), carboxypropyl (etherification), carboxybutyl (etherification) and other carboxyalkyl etherifications, and carboxyphenyl (etherification). As an example, the method of carboxymethylation will be described below.

[0027] The method of carboxymethylation is not particularly limited, and known methods can be used. For example, there is a method of mercerizing the cellulose raw material as the starting material and then etherifying it. A general-purpose solvent is used in the carboxymethylation reaction. Examples of the solvent include water, alcohol (e.g., lower alcohol) and a mixed solvent thereof. Examples of the lower alcohol include methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butyl alcohol, isobutyl alcohol, and tertiary butanol. The mixing ratio of the lower alcohol in the mixed solvent is usually 60% by mass or more or 95% by mass or less, and preferably 60 - 95% by mass. The amount of the solvent is usually 3 times by mass or more based on the cellulose raw material. The upper limit is not particularly limited, but it is 20 times by mass. Therefore, the amount of the solvent is preferably 3 - 20 times by mass.

[0028] Mercerization is usually carried out by mixing the cellulose raw material and a mercerizing agent. Examples of the mercerizing agent include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of the mercerizing agent used is preferably 0.5 times mol or more, more preferably 1.0 times mol or more, and even more preferably 1.5 times mol or more per anhydrous glucose residue of the starting material. The upper limit is usually 20 times mol or less, preferably 10 times mol or less, and more preferably 5 times mol or less. Therefore, 0.5 - 20 times mol is preferred, 1.0 - 10 times mol is more preferred, and 1.5 - 5 times mol is even more preferred. 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. Therefore, the reaction temperature is usually 0 to 70°C, preferably 10 to 60°C. The reaction time is usually 15 minutes or longer, preferably 30 minutes or longer. The upper limit is usually 8 hours or shorter, preferably 7 hours or shorter. Therefore, it is usually 15 minutes to 8 hours, preferably 30 minutes to 7 hours.

[0029] The etherification reaction is usually carried out by adding a carboxymethylating agent to the reaction system after mercerization. Examples of the carboxymethylating agent include sodium monochloroacetate. The addition amount of the carboxymethylating agent is preferably usually 0.05 times mole or more, more preferably 0.5 times mole or more, and even more preferably 0.8 times mole or more per glucose residue of the cellulose raw material. The upper limit is usually 10.0 times mole or lower, preferably 5 times mole or lower, and more preferably 3 times mole or lower. Therefore, it is preferably 0.05 to 10.0 times mole, more preferably 0.5 to 5 times mole, and even more preferably 0.8 to 3 times mole. The reaction temperature is usually 30°C or higher, preferably 40°C or higher, and the upper limit is usually 90°C or lower, preferably 80°C or lower. Therefore, the reaction temperature is usually 30 to 90°C, preferably 40 to 80°C. The reaction time is usually 30 minutes or longer, preferably 1 hour or longer. The upper limit is usually 10 hours or shorter, preferably 4 hours or shorter. Therefore, the reaction time is usually 30 minutes to 10 hours, preferably 1 hour to 4 hours. During the carboxymethylation reaction, the reaction solution may be stirred as necessary.

[0030] When modifying a cellulose raw material by carboxymethylation, the degree of carboxymethyl substitution per anhydrous glucose unit in the resulting carboxymethylated cellulose-based fiber is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.10 or more. The upper limit is preferably 0.50 or less, more preferably 0.40 or less, and still more preferably 0.35 or less. Therefore, the degree of carboxymethyl substitution is preferably from 0.01 to 0.50, more preferably from 0.05 to 0.40, and still more preferably from 0.10 to 0.35. The measurement of the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose-based fiber can be carried out, for example, by the following method. That is, 1) Weigh accurately about 2.0 g of carboxymethylated cellulose (absolutely dry) and put it into a 300 mL conical flask with a stopper. 2) Add 100 mL of special grade concentrated nitric acid to 1000 mL of methanol to obtain 100 mL of a nitric acid-methanol solution, shake for 3 hours, and convert the carboxymethyl cellulose salt (carboxymethylated cellulose) into hydrogen-type carboxymethylated cellulose. 3) Weigh accurately 1.5 - 2.0 g of hydrogen-type carboxymethylated cellulose (absolutely dry) and put it into a 300 mL conical flask with a stopper. 4) Moisten the hydrogen-type carboxymethylated cellulose with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. 5) Using phenolphthalein as an indicator, back-titrate the excess NaOH with 0.1 N H2SO4. 6) Calculate the degree of carboxymethyl substitution (DS) by the following formula. A = [(100 × F’ - (0.1 N H2SO4)(mL) × F) × 0.1] / (absolute dry mass of hydrogen-type carboxymethylated cellulose (g)) DS = 0.162 × A / (1 - 0.058 × A) A: Amount of 1 N NaOH (mL) required for neutralizing 1 g of hydrogen-type carboxymethylated cellulose F’: Factor of 0.1 N NaOH F: Factor of 0.1 N H2SO4

[0031] (Esterification of Cellulosic Fibers) Any method can be used for esterification as long as it introduces a functional group having anionic properties, and known methods can be employed. Examples include phosphoric acid esterification and sulfuric acid esterification. As an example, the methods of phosphoric acid esterification and sulfuric acid esterification will be described below.

[0032] (Phosphoric Acid Esterified Cellulose, Phosphorous Acid Esterified Cellulose) Phosphoric acid esterified cellulose is cellulose esterified with a compound having a phosphoric acid group or a phosphorous acid group. Examples of the compound having a phosphoric acid group or a phosphorous acid group include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, their esters and salts. These compounds are low-cost and easy to handle. Examples of the compound having a phosphate group or a phosphite group include phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, 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, sodium hydrogen phosphite, ammonium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid, etc. Among them, phosphoric acid, sodium salts of phosphoric acid, potassium salts of phosphoric acid, ammonium salts of phosphoric acid, phosphorous acid, sodium salts of phosphorous acid, potassium salts of phosphorous acid, and ammonium salts of phosphorous acid are preferred because of their high efficiency of phosphate esterification or phosphite esterification and easy industrial application. Sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydrogen phosphite, and sodium dihydrogen phosphite are more preferred. The compound having a phosphate group or a phosphite group may be used alone or in combination of two or more.

[0033] In phosphorylated cellulose and phosphitized cellulose, the lower limit of the introduction amount of the phosphate group or phosphite group per 1 g (mass) of phosphorylated cellulose or phosphitized cellulose is preferably 0.1 mmol / g or more. If it exceeds 3.5 mmol / g, the desired physical properties may not be obtained. The introduction amount of the phosphate group or phosphite group per 1 g (mass) of phosphorylated cellulose or phosphitized cellulose is preferably 0.1 to 3.5 mmol / g.

[0034] The phosphorylation reaction or the phosphite esterification reaction is carried out, for example, by reacting a cellulose raw material with a compound having a phosphate group or a phosphite group. Examples of the method of reacting the cellulose raw material with the compound having a phosphate group or a phosphite group include a method of mixing a powder or an aqueous solution of the compound having a phosphate group or a phosphite group with the cellulose raw material, and a method of adding an aqueous solution of the compound having a phosphate group or a phosphite group to a slurry of the cellulose raw material. Among these, from the reasons that the uniformity of the reaction is enhanced and the phosphorylation efficiency and the phosphite esterification efficiency are increased, the method of mixing an aqueous solution of the compound having a phosphate group or a phosphite group with the cellulose raw material or its slurry is preferable. The pH of the aqueous solution of the compound having a phosphate group or a phosphite group is preferably 7 or less from the viewpoint of enhancing the efficiency of introducing the phosphate group or the phosphite group, and more preferably 3 to 7 from the viewpoint of suppressing hydrolysis.

[0035] The lower limit of the addition amount of the compound having a phosphate group or a phosphite group is preferably 0.2 parts by mass or more, more preferably 1 part by mass or more in terms of phosphorus atom, based on 100 parts by mass of the cellulose raw material. By being in such a range, the yield of phosphorylated cellulose and phosphite esterified cellulose can be improved. On the other hand, the upper limit is preferably 500 parts by mass or less, more preferably 400 parts by mass or less. By being in such a range, a yield commensurate with the addition amount of the compound having a phosphate group or a phosphite group can be efficiently obtained. The addition amount of the compound having a phosphate group or a phosphite group is preferably 0.2 to 500 parts by mass, more preferably 1 to 400 parts by mass.

[0036] When reacting a cellulose raw material with a compound having a phosphate group or a phosphite group, a basic compound may be further added to the reaction system. Examples of the method of adding the basic compound include adding it to a slurry of the cellulose raw material, an aqueous solution of the compound having a phosphate group or a phosphite group, or a slurry of the cellulose raw material and the compound having a phosphate group or a phosphite group. The basic compound is not particularly limited, but a nitrogen-containing compound showing basicity is preferred. "Showing basicity" usually means that an aqueous solution of the basic compound exhibits a peach to red color in the presence of a phenolphthalein indicator, or the pH of the aqueous solution of the basic compound is greater than 7.

[0037] The nitrogen-containing compound showing basicity is not particularly limited as long as the effects of the present invention are achieved. Among them, a compound having an amino group is preferred. For example, urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine can be mentioned. Among these, urea is preferred for reasons of low cost and easy handling. The addition amount of the basic compound is preferably 2 to 1000 parts by mass, more preferably 100 to 700 parts by mass. The reaction temperature is preferably 0 to 95°C, more preferably 30 to 90°C. The reaction time is not particularly limited, but is usually about 1 to 600 minutes, preferably 30 to 480 minutes. When the reaction conditions are within any of these ranges, it is possible to prevent excessive introduction of phosphate groups or phosphite groups into the cellulose and make it easily soluble, and the yields of phosphoric acid esterified cellulose and phosphorous acid esterified cellulose can be improved.

[0038] After reacting a cellulose raw material with a compound having a phosphate group or a phosphite group, a suspension is usually obtained. The suspension is dehydrated as necessary. After dehydration, heat treatment is preferably performed. Thereby, hydrolysis of the cellulose raw material can be suppressed. The heating temperature is preferably 100 to 170 °C. While water is contained during the heat treatment, it is heated at 130 °C or lower (more preferably 110 °C or lower), and after removing the water, it is more preferably heated at 100 to 170 °C. Phosphoric acid esterified cellulose and phosphorous acid esterified cellulose are preferably subjected to a washing treatment such as washing with cold water after boiling.

[0039] (Sulfonated cellulose) Sulfonated cellulose is cellulose sulfonated with a compound having a sulfate group. Examples of the compound having a sulfate group include sulfuric acid, sulfamic acid, chlorosulfonic acid, sulfur trioxide, esters and salts thereof. These compounds are low in cost and easy to handle. As the sulfonation reagent, sulfamic acid is preferably used. Sulfamic acid not only has a lower solubility in cellulose than sulfuric anhydride or sulfuric acid aqueous solution, but also has a low acidity, so that the degree of polymerization can be maintained. In addition, there are no handling restrictions on sulfuric anhydride or sulfuric acid aqueous solution, which is strongly acidic and highly corrosive, and it is not designated as a specified substance under the Air Pollution Control Law, so the environmental load is small. The amount of sulfamic acid used can be appropriately adjusted in consideration of the amount of substituents introduced into the cellulose-based fiber. Sulfamic acid can be used, for example, preferably in an amount of 0.01 to 50 mol, more preferably 0.1 to 30 mol, per mol of glucose unit in the cellulose molecule.

[0040] <Loading of metal ions and / or metal particles> By supporting ions or metal particles of one or more metal elements selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu on anionic modified cellulose fibers, a high antiviral, antibacterial, and deodorizing effect can be imparted. In particular, by using Ag and Cu, the antiviral, antibacterial, and deodorizing functions are further improved. In particular, for anionic modified cellulose fibers, since this metal and the anionic modified cellulose fibers are chemically bonded, when contained in the base paper for paper yarn, the metal component is less likely to desorb from the base paper for paper yarn, and the mechanical properties such as tensile strength are also good.

[0041] The method for supporting the metal ions on the anionic modified cellulose fibers is not particularly limited. For example, a previously prepared dispersion of the anionic modified cellulose fibers and an aqueous solution of a metal compound may be mixed, or a dispersion containing the anionic modified cellulose fibers may be coated on a substrate to form a film, and the film may be brought into contact with an aqueous solution of a metal compound. At this time, the film may remain fixed on the substrate or may be in a state of being peeled off from the substrate. By these methods, the metal ions derived from the metal compound undergo counter-ion exchange with the sodium ions that have already been ionically bonded to an anionic group such as a carboxylate group, so that metal ions are added to the anionic modified cellulose fibers. This counter-ion exchange is considered to occur due to the difference in the ionization tendency between metal ions.

[0042] Here, the aqueous solution of the metal compound is an aqueous solution of a metal salt. Examples of the metal salt include complexes (complex ions), halides, nitrates, sulfates, and acetates. The amount of the aqueous solution of the metal compound used is not particularly limited, but 0.2 to 2.2 mmol of metal ions per 1 g of the anionic modified cellulose fibers is preferable, and 0.4 to 1.8 mmol is more preferable. The time for contacting the metal compound may be adjusted as appropriate. The temperature during contact is not particularly limited, but is preferably in the range of 2 to 50° C. Furthermore, the pH of the liquid during contact is not particularly limited, but since a low pH makes it difficult for metal ions to bind to anionic groups, the pH is preferably in the range of 7 to 13, and particularly preferably in the range of 8 to 12.

[0043] In the present invention, it is possible to introduce metal ions into the anion-modified cellulose fiber as described above, but some of the metal ions may be reduced to form metal particles. If necessary, it is also possible to partially form metal particles on the surface of the anion-modified cellulose fiber by reducing some of the metal ions bound to the metal ion-supported anion-modified cellulose fiber by adding a reducing agent or the like. However, it is preferable to use the entire amount of the metal compound as metal ions without carrying out any special reduction treatment from the viewpoint of antiviral, antibacterial, and deodorizing effects.

[0044] The mechanism by which metal particles are generated in the anion-modified cellulose fiber by reducing the metal compound in the metal-containing anion-modified cellulose fiber obtained above is not clear, but is presumed to be as follows. The metal compound or ions derived from the metal compound in the metal compound-containing anion-modified cellulose fiber are reduced to metal by the reduction reaction. At this time, the generated metal is supported on the surface of the anion-modified cellulose fiber. Since the metals generated in the same manner and adjacent to each other are integrated, the particles grow to form nanoparticles. Meanwhile, metal compounds and the like that exist in the vicinity of the anion-modified cellulose fiber but are not bonded to the anion-modified cellulose fiber are also reduced to generate metal. The metal is quickly integrated with the metal on the surface of the cellulose fiber to form metal particles.

[0045] The reduction reaction may be carried out by a known method, but it is preferably carried out while reducing the metal compound without cleaving the bond between the metal compound and the acid group. Examples of such reduction methods include a gas-phase reduction method using hydrogen and a liquid-phase reduction method 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. For example, the reaction may be carried out at 50 to 60 °C for about 1 to 3 hours. The gas-phase reduction reaction is preferably carried out in a state where the metal-containing anion-modified cellulose-based fiber does not contain water or a solvent. In the case of liquid-phase reduction, a film can be obtained from the above dispersion and subjected to the reduction reaction with or without drying. The film may remain fixed on the substrate or may be in a state peeled off from the substrate. Further, the dispersion can be directly subjected to the liquid-phase reduction reaction without drying. The reaction temperature in the liquid-phase reduction is preferably 4 to 40 °C, more preferably room temperature.

[0046] The fact that the anion-modified cellulose-based fiber contains metal ions or metal particles can be confirmed by a scanning electron microscope image and ICP emission analysis of the extract with a strong acid. That is, the metal ions cannot be confirmed in the scanning electron microscope image, while it can be confirmed by ICP emission analysis that the metal is contained. On the other hand, for example, when the above metal is reduced from ions and exists as metal particles, the metal particles can be confirmed in the scanning electron microscope image, so the presence or absence of metal ions can be determined. Further, the presence or absence of metal ions can also be determined by element mapping using a scanning electron microscope image and energy-dispersive X-ray analysis (EDS). That is, metal ions cannot be confirmed in the scanning electron microscope image, but the presence of metal ions can be confirmed by performing element mapping.

[0047] In the step of supporting the metal ions or metal particles, the metal content in the anion-modified cellulose fiber is preferably in the range of 10 to 100 mg / g, more preferably in the range of 15 to 80 mg / g, and particularly preferably in the range of 20 to 60 mg / g, based on 1 g of the anion-modified cellulose fiber. If it is less than 10 mg / g, the antiviral, deodorizing, and antibacterial functions may be inferior. On the other hand, if it exceeds 100 mg / g, metal ions are likely to elute during production, increasing the load of wastewater treatment. The metal content of the anion-modified cellulose fiber can be measured by the following method. (1) Before measurement, the sample for measurement is dried (at 50 °C for 1 day). (2) Weigh 0.25 g of the dried sample for measurement and put it into a 50 ml beaker. (3) Pipette 10 ml of concentrated nitric acid and add it to the beaker containing the sample for measurement to prepare a measurement sample solution. (4) After standing for 120 minutes, pass it through a syringe filter to remove (filter) the fiber component from the measurement sample solution. (5) Pipette 1 ml of the filtered measurement sample solution and add it to a test tube containing 49 ml of distilled water. (6) Close the lid of the test tube tightly and shake it to stir. (7) Use ICP-OES (manufactured by Agilent Technology, ICP-OES 5110) to measure (quantify) the content of metal ions and metal particles. (8) Calculate the metal content (mg / g) per 1 g of the anion-modified cellulose fiber from the quantitative result by ICP-OES.

[0048] (Pulp) The pulp that makes up the base paper for paper yarns of the present invention can use chemical pulps such as bleached kraft pulp (BKP), unbleached kraft pulp (UKP), semi-bleached kraft pulp (SBKP), sulfite pulp, etc., and mechanical pulps such as stone ground pulp (SGP), pressure stone ground pulp (TGP), chemiground pulp (CGP), groundwood pulp (GP), thermomechanical pulp (TMP), etc., dissolving pulp, and pulp using softwood or hardwood such as mercerized pulp as raw materials. In the present invention, as the wood pulp, softwood pulp with a long fiber length is preferably used. Also, non-wood pulps such as bast fibers like flax, kenaf, paper mulberry, and mitsumata, hard fibers like bagasse, bamboo, and esparto, seed hair fibers like cotton pulp, and leaf sheath / leaf fibers like abaca pulp and sisal pulp can be used. In the present invention, as the non-wood pulp, hemp pulp is preferred, and in particular, abaca pulp having a long fiber length and an appropriate fiber width is preferably used. The drainage degree (Canadian standard drainage degree) of the pulp is usually about 300 - 680 ml and can be appropriately adjusted according to the physical properties required for the base paper for paper yarns.

[0049] (Pulp formulation) The blending ratio (mass ratio: total is 100) of pulp and metal-containing anionic modified cellulose fibers is not particularly limited, but usually, pulp / metal-containing anionic modified cellulose fibers = 95 / 5 - 75 / 25 (solid content). If the blending amount of the metal pulp is small, the deodorizing, antibacterial, and antiviral effects may not be fully manifested. On the other hand, if the blending amount is too large, the strength of the base paper for paper yarns may not be obtained.

[0050] (Additives) It is preferable to blend at least one of a dry paper strength agent (dry paper strength enhancer) and a wet paper strength agent (wet paper strength enhancer) in the base paper for paper yarns of the present invention. For the dry paper strength agent, carboxymethyl cellulose (CMC), carboxymethyl guar gum, polyacrylamide, glyoxal-modified polyacrylamide, hydroxypropyl guar gum, etc. can be used. As the wet paper strength enhancer, dialdehyde guar gum, glyoxal-modified polyacrylamide, polyamide epichlorohydrin, polyamide polyamine epichlorohydrin, polyamine epichlorohydrin, polyethyleneimine, etc. can be used. In particular, adding both amphoteric dry paper strength agent and wet paper strength agent is preferable from the viewpoints of water resistance and washing resistance.

[0051] The addition amount of the dry paper strength enhancer is not less than 0.20% by mass, preferably not less than 0.30% by mass, more preferably not less than 0.35% by mass, and not more than 1.2% by mass, preferably not more than 1.1% by mass, more preferably not more than 1.0% by mass, based on the total amount of pulp and metal-containing anionic modified cellulose fibers. The addition amount of the wet paper strength enhancer is not less than 0.3% by mass, preferably not less than 0.5% by mass, more preferably not less than 0.8% by mass, and not more than 4.0% by mass, preferably not more than 3.0% by mass, more preferably not more than 2.0% by mass, based on the total amount of pulp and metal-containing anionic modified cellulose fibers.

[0052] Also, the compounding amount of the water-soluble aluminum salt (aluminum sulfate) is preferably not more than 0.3% by mass, more preferably not more than 0.2% by mass, further preferably not more than 0.1% by mass, and most preferably not containing (0% by mass), based on the total amount of pulp and metal-containing anionic modified cellulose fibers. When papermaking is carried out with a paper stock containing a water-soluble aluminum salt, problems such as the metal contained in the metal-containing anionic modified cellulose fibers being replaced by aluminum and the wastewater being contaminated with heavy metals may occur.

[0053] (Other auxiliaries) In the present invention, examples of various auxiliaries include a retention aid, a drainage improver, a coagulant, a bulking agent, a dye, a fluorescent brightening agent, a pH adjuster, an antifoaming agent, an ultraviolet inhibitor, a color fading inhibitor, a pitch control agent, a slime control agent, etc., and they can be appropriately selected and used as needed.

[0054] (Papermaking) The papermaking method of the paper yarn base paper is not particularly limited, and it can be carried out using a Fourdrinier paper machine, a cylinder paper machine, a Duoformer paper machine, an inclined Duoformer paper machine, etc. Among these, it is preferable to use a cylinder paper machine that can increase the fiber orientation. Also, for the drying process, a multi-cylinder cylinder dryer, a Yankee dryer, a hot air dryer, etc. can be appropriately selected.

[0055] (Metal content) The paper yarn base paper of the present invention preferably has a metal content of 0.25 mass% or more. By having a metal content of 0.25 mass% or more, a high deodorizing, antibacterial, and antiviral effect can be exhibited. The metal content of the paper yarn base paper can be measured by the following method. (1) Before measurement, the measurement sample is dried (at 50°C for 1 day). (2) Weigh 0.25 g of the dried measurement sample and put it into a 50 ml beaker. (3) Take 10 ml of concentrated nitric acid with a whole pipette and add it to the beaker containing the measurement sample to prepare a measurement sample solution. (4) After standing for 120 minutes, pass it through a syringe filter to remove (filter) the fiber component from the measurement sample solution. (5) Take 1 ml of the filtered measurement sample solution with a micropipette and add it to a test tube containing 49 ml of distilled water. (6) Close the lid of the test tube tightly and shake it to stir. (7) Use ICP-OES (manufactured by Agilent Technology, ICP-OES 5110) to measure (quantify) the content of metal ions and metal particles. (8) Calculate the amount of metal (mass%) in the paper yarn base paper from the quantitative results by ICP-OES. The metal content can be adjusted with the blending amount of the metal-containing anion-modified cellulose fiber.

[0056] (Manufacture of paper yarn) The obtained base paper for paper yarn is slit into strips and subjected to a process of twisting it spirally to obtain paper yarn (twisted yarn). The paper yarn can be blended with a flame retardant, pigment, water repellent, oil repellent, resin, and other functional additives within a range that does not impair the effects of the present invention. The timing of blending can be imparted not only in the papermaking process but also in other separate processes such as coating, dipping, and dyeing.

[0057] The paper yarn can be used for fiber products and fabric products in various industrial fields. For example, curtains, partitions, furniture fabrics, tatami mats, wallpapers, carpets, towels, handkerchiefs, pillow covers, sheets, mats, carpets, jackets, skirts, dresses, denim pants, knits, sweaters, underwear, scarves, socks, gloves, hats, stockings, shoes, shoe insoles, bags, white coats, surgical masks, diapers, medical, nursing, and sanitary products, body cleaning sheets, and hand towels, etc. can be mentioned.

Examples

[0058] · Preparation of copper-containing anion-modified cellulose fiber 500 g (bone-dry) of a cellulose raw material (bleached unbeatened kraft pulp derived from softwood) was added to 500 ml of an aqueous solution in which 780 mg of TEMPO (Sigma Aldrich) and 75.5 g of sodium bromide were dissolved, and stirred until the pulp was uniformly dispersed. An aqueous sodium hypochlorite solution was added to the reaction system to a concentration of 6.0 mmol / g to initiate the oxidation reaction. During the reaction, the pH in the system decreased, but a 3M aqueous sodium hydroxide solution was sequentially added to adjust the pH to 10. The reaction was terminated when the sodium hypochlorite was consumed and the pH in the system no longer changed. The mixture after the reaction was filtered through a glass filter to separate and wash the pulp to obtain oxidized cellulose fibers with an acid value of 1.6 mmol / g. To the TEMPO-oxidized cellulose fibers obtained by the above operation, an aqueous solution of a metal salt (CuCl2) at 1.6 mmol per 1 g of the oxidized cellulose fibers was added and stirred. As a result, the oxidized cellulose fibers were made to contain Cu ions, and they were washed to remove unreacted metal salts. The average fiber length was 1.93 mm, the average fiber diameter was 31.2 μm, the Canadian Standard Freeness was 600 ml, and the copper content was 44.7 mg per 1 g of the copper-containing anionic-modified cellulose fibers.

[0059] (Example 1) 90 parts by mass of abaca pulp with a Canadian Standard Freeness (CSF) of 400 ml and 10 parts by mass of copper-containing anionic-modified cellulose-based fibers were mixed to obtain a slurry. As an amphoteric dry-strength agent, polyacrylamide resin (Harmide KS2, non-volatile content 20%, pH 3.0 to 5.0, manufactured by Harima Kasei Co., Ltd.) was added at a solid content of 0.9% with respect to the fibers (dry mass) while stirring. As a cationic wet-strength enhancer, polyamide epichlorohydrin resin (WS4024, non-volatile content 25%, pH 2.5 to 5.0, manufactured by Starlight PMC Co., Ltd.) was added at a solid content of 1.875% with respect to the total of the fibers (the total of pulp and copper-containing anionic-modified cellulose-based fibers, dry mass) while stirring to prepare a papermaking raw material. Using this papermaking raw material, 2 a paper yarn base paper was obtained by papermaking with a cylinder mold paper machine at a target basis weight of 15 g / m

[0060] (Example 2) A paper yarn base paper was obtained in the same manner as in Example 1, except that 45 parts by mass of abaca pulp with a Canadian Standard Freeness (CSF) of 400 ml, 45 parts by mass of NBKP with a Canadian Standard Freeness (CSF) of 400 ml, and 10 parts by mass of copper-containing anionic-modified cellulose-based fibers were mixed to obtain a slurry. (Example 3) A paper yarn base paper was obtained in the same manner as in Example 1, except that 90 parts by mass of NBKP with a Canadian Standard Freeness (CSF) of 400 ml and 10 parts by mass of copper-containing anionic-modified cellulose-based fibers were mixed to obtain a slurry.

[0061] (Example 4) A slurry was prepared in the same manner as in Example 1. As an amphoteric dry-strength agent for this slurry, polyacrylamide resin (Harmide KS2, non-volatile content 20%, pH 3.0 - 5.0, manufactured by Harima Kasei Co., Ltd.) was added while stirring at a solid content of 0.45% based on the slurry (dry mass). As a cationic wet-strength enhancer for this, polyamide epichlorohydrin resin (WS4024, non-volatile content 25%, pH 2.5 - 5.0, manufactured by Seiko PMC Co., Ltd.) was added while stirring at a solid content of 0.938% based on the fiber (dry mass) to prepare a papermaking raw material. Using this papermaking raw material, paper yarn base paper was obtained by papermaking with a cylinder mold paper machine at a target basis weight of 15 g / m 2 ².

[0062] (Example 5) A slurry was prepared in the same manner as in Example 1. As a cationic dry-strength agent for this slurry, polyacrylamide resin (DA4136, non-volatile content 15%, pH 5.0 - 7.0, manufactured by Seiko PMC Co., Ltd.) was added while stirring at a solid content of 0.9% based on the slurry (dry mass), and as a fixing agent, an aqueous aluminum sulfate solution (Liquid Sulfate Band, non-volatile content 27%, pH 2.1 / 20 °C, manufactured by Asahi Chemical Industry Co., Ltd.) was added while stirring at a solid content of 0.81% based on the fiber (dry mass). As a cationic wet-strength enhancer for this, polyamide epichlorohydrin resin (WS4024, non-volatile content 25%, pH 2.5 - 5.0, manufactured by Seiko PMC Co., Ltd.) was added while stirring at a solid content of 1.875% based on the fiber (dry mass) to prepare a papermaking raw material. Using this papermaking raw material, paper yarn base paper was obtained by papermaking with a cylinder mold paper machine at a target basis weight of 15 g / m 2 ².

[0063] (Example 6) A slurry was prepared in the same manner as in Example 1. As a cationic dry-strength agent, polyacrylamide resin (DA4136, non-volatile content 15%, pH 5.0 - 7.0, manufactured by Starlight PMC Co., Ltd.) was added at a solid content of 0.45% based on the slurry (dry mass), and as a fixing agent, an aqueous aluminum sulfate solution (liquid sulfuric acid band, non-volatile content 27%, pH 2.1 / 20 °C, manufactured by Asahi Chemical Industry Co., Ltd.) was added at a solid content of 0.405% based on the natural fiber (dry mass) while stirring. As a cationic wet-strength enhancer, polyamide epichlorohydrin resin (WS4024, non-volatile content 25%, pH 2.5 - 5.0, manufactured by Starlight PMC Co., Ltd.) was added at a solid content of 0.940% based on the slurry (dry mass) while stirring to prepare a papermaking raw material. Using this papermaking raw material, 2 a paper yarn base paper was obtained by papermaking with a cylinder mold paper machine at a target basis weight of 15 g / m

[0064] (Example 7) A paper yarn base paper was obtained in the same manner as in Example 1, except that the target basis weight was 11.3 g / m 2 . (Example 8) A paper yarn base paper was obtained in the same manner as in Example 1, except that the target basis weight was 7.5 g / m 2 .

[0065] (Example 9) A paper yarn base paper was obtained in the same manner as in Example 1, except that 90 parts by mass of abaca pulp with a Canadian standard freeness (CSF) of 600 ml and 10 parts by mass of copper-containing anionic modified cellulose-based fibers were mixed to obtain a slurry. (Example 10) A paper yarn base paper was obtained in the same manner as in Example 9, except that the target basis weight was 11.3 g / m 2 .

[0066] (Comparative Example 1) A paper yarn base paper was obtained in the same manner as in Example 1, except that copper-containing anionic modified cellulose-based fibers were not used. (Comparative Example 2) A paper yarn base paper was obtained in the same manner as in Example 1, except that papermaking was carried out at a target basis weight of 4.5 g / m 2 . (Comparative Example 3) Target basis weight: 42 g / m 2 A paper yarn base paper was obtained in the same manner as in Example 1, except that it was made by papermaking.

[0067] The following evaluations were performed on the obtained paper yarn base paper. The results are shown in Tables 1 and 2. (1) Basis weight Measured in accordance with JIS P 8124. (2) Thickness Measured in accordance with JIS P 8118. (3) Density Calculated from the values of basis weight and thickness. (4) Tensile strength Measured in accordance with JAPAN TAPPI No.71. (5) Wet tensile strength After immersing in water for 30 seconds, it was measured in accordance with JAPAN TAPPI No.71. (6) Copper content Measured by ICP emission spectrometry (ICP-OES).

[0068] (7) Twisting property and strength The base paper for paper yarns obtained in the examples and comparative examples was processed into a slit shape with a width of 1.5 mm by a slitter device to produce a paper tape, and then the paper tape was twisted by a paper string manufacturing machine to produce paper yarns. The twisting property of the paper yarns was judged according to the following evaluation criteria. · Twisting property 〇: The appearance of the yarn is uniform. △: The appearance of the yarn is slightly non-uniform. ×: There are many untwisted open areas. · Strength 〇: The yarn cannot be easily cut even when pulled by hand. ×: The yarn can be easily cut when pulled by hand. (8) Deodorizing property The deodorizing function test was carried out on 1 g of the twisted test piece using hydrogen sulfide as the target according to the method of the SEK Mark textile product certification standard (JEC301, Fiber Evaluation Technology Council). The deodorizing function was evaluated according to the following criteria. ◎: The reduction rate of hydrogen sulfide is 80% or more ○: Hydrogen sulfide reduction rate is 70% or more and less than 80% ×: Hydrogen sulfide reduction rate is less than 70%

[0069] (9) Antibacterial property According to JIS L1902 "Test Method and Antibacterial Effect of Antibacterial Property of Textile Products", a qualitative test by the bacterial liquid absorption method was carried out. Specifically, 0.2 ml of the test bacterial liquid containing Escherichia coli and Staphylococcus aureus was dropped onto 0.4 g of the twisted yarn test piece. After culturing at 37 °C for 18 - 24 hours, 20 ml of the washing liquid was added to wash out the test bacteria from the test piece, and the viable bacteria count in the washing liquid was measured by the mixed plate culture or luminescence measurement method, and the antibacterial function was evaluated according to the following criteria. ◎: Antibacterial activity value A ≥ 3.0 according to JIS 〇: Antibacterial activity value 3.0 > A ≥ 2.0 according to JIS ×: Antibacterial activity value 2.0 > A according to JIS

[0070] (10) Antiviral property The antiviral function test was carried out in accordance with JIS L 1922:2016, with the mass of the twisted yarn test piece being 0.4 g. As the test viruses, influenza virus (H3N2, ATCC VR - 1679) and feline calicivirus (Strain: F - 9 ATCC VR - 782) were used. The antiviral activity value (Mv) was calculated and evaluated according to the following criteria. ◎: Antiviral activity value Mv ≥ 3.0 according to JIS 〇: Antiviral activity value 3.0 > Mv ≥ 2.0 according to JIS ×: Antiviral activity value 2.0 > Mv according to JIS

[0071] [Table 1]

[0072] [Table 2]

[0073] The base paper for paper yarns obtained in Examples 1 to 10 of the present invention was excellent in twistability and was able to obtain paper yarns excellent in strength. On the other hand, the base paper for paper yarns obtained in Comparative Example 2 was inferior in strength, and the base paper for paper yarns obtained in Comparative Example 3 was inferior in twistability. The base paper for paper yarns obtained in Examples 1 to 4 had a higher metal content than the base paper for paper yarns obtained in Examples 5 and 6, and was able to more strongly exhibit the effects derived from the metal.

Claims

1. a pulp and a metal-containing anionic modified cellulose fiber containing one or more metal ions and / or metal particles selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu; The basis weight is 5 to 40 g / m ２ , a base paper for paper yarns, characterized in that the longitudinal tensile strength is 12 N / 15 mm or more, the longitudinal wet tensile strength is 3.0 N / 15 mm or more, and the horizontal / longitudinal ratio of the tensile strength and the wet tensile strength is 25% or less.

2. The base paper for paper yarn according to claim 1, wherein the metal-containing anionic modified cellulose fiber is a Cu-containing anionic modified cellulose fiber.

3. The base paper for paper yarn according to claim 1 or 2, wherein the Cu content is 0.25% by mass or more.

4. The base paper for paper yarn according to claim 1 or 2, wherein the pulp contains at least one of softwood pulp and hemp pulp.

5. The base paper for paper yarn according to claim 1 or 2, comprising an amphoteric dry paper strength agent and a wet paper strength agent.

6. The base paper for paper yarn according to claim 1 or 2, wherein the content of the water-soluble aluminum salt is 0.3% by mass or less based on the total of the pulp and the metal-containing anionic modified cellulose fiber.

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