JP2017155364A - Non-woven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-woven fabric that dynamics properties are good, can prevent falling of deodorization and antimicrobe components, and keeps deodorization and antimicrobe effects without depending on humidity and in wetting condition.SOLUTION: A non-woven fabric contains metal ion-containing cellulosic fiber that cellulosic fiber having carboxyl group or carboxylate group on the surface contains one or more metal ions chosen from a group of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn and Cu, and synthetic fiber.SELECTED DRAWING: None

Description

  The present invention relates to a nonwoven fabric. More specifically, the present invention relates to a nonwoven fabric having a deodorizing and antibacterial function.

  In general, a nonwoven fabric is a fiber in which synthetic fibers are laminated without being woven and spread into a sheet, and the fibers are appropriately bonded by an appropriate method. Non-woven fabrics can be produced in large quantities at low cost because there is no process of spinning and weaving or knitting like a fabric. In addition, by combining with raw materials, manufacturing methods, and other materials, it is easy to adjust various functions such as air permeability and filterability, which are structural features of nonwoven fabric, according to the required quality. It is. Because of these characteristics, non-woven fabrics are various such as diapers, sanitary products such as sanitary products, wipers, masks, filters for gas or liquid filtration, building materials such as roofing materials (roofing materials) and civil engineering, automobile interior materials, clothing, etc. Widely used in various fields.

In the use of the above-described nonwoven fabric, in addition to mechanical properties such as tensile strength and tear strength required for nonwoven fabrics in general, deodorization and / or antibacterial functions are often required. For example, in the use of sanitary goods such as diapers, effective odor components such as ammonia, trimethylamine, hydrogen sulfide, and methyl mercaptan (such as human urine odor, stool odor, and rotten odor) are effective. And it is required to continuously suppress.
In addition, in filter applications, in addition to the moderate air permeability and particle collection required for filters in general, the deodorizing function described above, and the growth and development of mold and mycelia especially when used under high humidity Effective and continuous control is required.

  In order to impart these deodorant and antibacterial functions, various methods have been proposed. In Patent Documents 1 and 2, one aqueous solution of a silicon compound or an aluminum compound, which is a constituent component of zeolite, is impregnated into a hydrophilic polymer substrate such as cellulose fiber, and a basic substance and the other aqueous solution are mixed. An inorganic porous crystal-hydrophilic polymer composite in which a material is further impregnated and zeolite is supported inside a cellulosic fiber has been proposed. Furthermore, it is disclosed that an antibacterial effect and a deodorizing effect can be imparted by supporting a metal on the zeolite.

  Patent Document 3 discloses that 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 aluminum are heated inside the cellulosic fiber by heating with moisture. A cellulosic fiber structure is disclosed which reacts with a compound to produce a silica-alumina porous zeolite. Furthermore, it is disclosed that antibacterial and antifungal properties can be imparted by introducing metal ions into the silica / alumina porous body.

  Patent Document 4 discloses an antibacterial cellulose fiber containing one or more silver antibacterial agents selected from silver zeolite, silver zirconium phosphate, silver calcium phosphate, and silver-dissolving glass. Furthermore, a nonwoven fabric using this antibacterial cellulosic fiber is disclosed.

  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 absolutely dry weight of the oxidized pulp. A certain paper base material is disclosed, and it is also described that fibers produced from a synthetic resin are contained in a certain range with respect to the paper base material.

JP-A-10-120923 JP 11-315492 A JP 2008-031591 A Japanese Patent Laid-Open No. 11-107033 International Publication No. 2014/097929

However, Patent Documents 1 to 4 only describe a simple mixture of an inorganic compound containing a cellulose fiber and a metal component, and the cellulose fiber and the inorganic compound containing the metal component are chemically bonded to each other. I don't mean. In other words, since inorganic compounds containing metal components do not form a physical / chemical network like fibers, when non-woven fabrics are produced using them, the mechanical properties of the substrate, such as tensile strength and tear strength, are reduced. In addition to the reduction, there is a problem that an inorganic compound containing a metal component falls off from the substrate.
Furthermore, there is a problem that the deodorizing / antibacterial effect is lowered when the nonwoven fabric is placed in a high humidity environment or wet. Here, when wet, for example, refers to a state in which moisture is contained in a mass ratio of 100% or more with respect to a certain mass after drying of the nonwoven fabric.
Moreover, in the paper base material of patent document 5, it cannot be said that the deodorizing effect is enough.

  Accordingly, an object of the present invention is to provide a non-woven fabric that has good mechanical properties, can suppress the deodorization / antibacterial component from falling off, and has a deodorization / antibacterial effect that is not dependent on humidity and is secured even when wet.

  In order to achieve the above-mentioned object, the nonwoven fabric of the present invention is made of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn with respect to cellulosic fibers having a carboxyl group or a carboxylate group on the surface. And a metal ion-containing cellulosic fiber containing at least one metal ion selected from the group of Cu and a synthetic fiber.

In the metal ion-containing cellulose fiber, it is preferable that a part of the hydroxyl group at the C6 position in the glucose unit of cellulose is oxidized to a carboxyl group.
The metal ions are preferably Ag ions or Cu ions.
It is preferable to further include a cellulosic fiber that does not contain metal ions.

  According to the present invention, it is possible to obtain a non-woven fabric that has good mechanical properties, can suppress the deodorization / antibacterial component from falling off, and ensures the deodorization / antibacterial effect regardless of humidity and even when wet.

  The nonwoven fabric which concerns on embodiment of this invention is from the group of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu with respect to the cellulosic fiber which has a carboxyl group or a carboxylate group on the surface. A metal ion-containing cellulosic fiber containing at least one selected metal ion and a synthetic fiber. Details will be described below.

<1. Metal ion-containing cellulose fiber>
The nonwoven fabric which concerns on embodiment of this invention is chosen from the group of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu with respect to the cellulose fiber which has a carboxyl group or a carboxylate group. A metal ion-containing cellulosic fiber containing one or more metal ions is included.
The content of the metal ion-containing cellulose fiber is preferably 1% by mass or more with respect to the nonwoven fabric. If the content is less than 1% by mass, sufficient deodorizing and antibacterial effects may not be imparted. The upper limit of the content is not particularly limited, and can be adjusted as appropriate according to the degree of deodorization / antibacterial effect to be obtained. However, from the viewpoint of cost and the like, it can be, for example, 95% by mass.

<2. Cellulose fiber not containing metal ions>
In addition to the metal ion-containing cellulose fiber, the nonwoven fabric according to the embodiment of the present invention is a cellulose fiber that does not contain metal ions (hereinafter referred to as “general cellulosic fiber”). It may be contained depending on the function desired.
General cellulosic fibers include, for example, wood pulp; bamboo, cotton, hemp, jute, kenaf, farmland waste, non-wood products such as animals (eg, ascidians), algae, microorganisms (eg, acetic acid bacteria (Acetobacter)) Pulp.
Wood pulp is preferred as the general cellulosic fiber, and one or more general cellulosic fibers can be mixed and used.

  The content of the metal ion-containing cellulosic fiber is preferably 1% by mass or more, and the content of the synthetic fiber described later is preferably 5% by mass or more. The amount is preferably 94% by mass or less. The lower limit of the content of the general cellulosic fiber is not particularly limited, and the general cellulosic fiber may not be included.

The number average fiber diameter and the number average fiber length of the metal ion-containing cellulose fiber and the general cellulosic fiber are not particularly limited, and required mechanical properties such as tensile strength and tear strength, air permeability, Any value can be used depending on the texture and the like. Further, two or more kinds of fibers having different number average fiber diameters and number average fiber lengths may be mixed and used at an arbitrary ratio.
As an example, in the case of softwood kraft pulp (NBKP) which is one of natural cellulose fibers, the number average fiber diameter is about 30 to 60 μm, the number average fiber length is about 3 to 5 mm, and in the case of hardwood bleached kraft pulp (LBKP), several The average fiber diameter is about 10 to 30 μm, and the number average fiber length is about 1 to 2 mm.

The metal ion-containing cellulosic fibers and the general cellulosic fibers may be subjected to a beating treatment one or more times in the production process until they are contained in the nonwoven fabric. Here, the beating process is a process for applying a mechanical shearing force to the fiber. By the beating treatment, a part of the cellulosic fiber is fibrillated or nanofibered, and mechanical properties such as tensile strength are improved.
In particular, in the case of a metal ion-containing cellulose fiber, the deodorizing effect and antibacterial effect after supporting the metal ion can be further enhanced by performing the beating treatment.

Generally, freeness (CSF) is used as an index of the beating degree. The freeness of the metal ion-containing cellulose fiber is preferably in the range of 30 to 600 ml.
If the freeness is lower than 30 ml, the yield in the non-woven fabric is reduced in the nonwoven fabric manufacturing process. If the freeness is higher than 600 ml, the fibrillation is insufficient and the deodorization / antibacterial effect May decrease.
The freeness of the general cellulosic fiber is not particularly limited, and can be freely selected from a general freeness range, for example, a range of 5 to 950 ml, depending on the desired quality.

  The apparatus used for beating is not specifically limited, A well-known apparatus can be used arbitrarily. Examples of beating devices include refiners, beaters, PFI mills, kneaders, dispersers, etc., which operate metal or blade and pulp fibers around the rotation axis, those caused by friction between pulp fibers, high-pressure homogenizers, ultra-high pressure homogenizers , Nanomizers, various mills, stone mills and the like.

<3. Production of metal ion-containing cellulose fiber>
The metal ion-containing cellulosic fiber is obtained by introducing a carboxyl group or a carboxylate group into a surface glucose unit by chemically modifying a general cellulosic fiber as follows, and further supporting metal ions thereafter. Can be manufactured.
Hereinafter, a method for introducing a carboxyl group or a carboxylate group into a glucose unit on the surface of the cellulosic fiber and a method for supporting a metal ion thereafter will be described.

<3-1. Introduction of carboxyl group or carboxylate group>
Cellulose has three hydroxyl groups per glucose unit and can be subjected to various chemical modification treatments. In this invention, the modification | denaturation which introduce | transduces a carboxyl group or a carboxylate group with respect to at least one part of a cellulosic fiber in the process mentioned later is performed.
Here, the carboxyl group refers to a group represented by —COOH, and the carboxylate group refers to a group represented by —COO—. The counter ion of the carboxylate group is not particularly limited. The carboxyl group or carboxylate group is also referred to as an “acid group”.

  The content of acid groups can be measured by the method disclosed in paragraph 0021 of JP2008-001728A. That is, using a precisely weighed dry cellulose sample, 60 mL of a 0.5 to 1 mass% slurry is prepared, and the pH is adjusted to about 2.5 with a 0.1 mol / L hydrochloric acid aqueous solution. Then, 0.05 mol / L sodium hydroxide aqueous solution is dripped and electrical conductivity measurement is performed. The measurement is continued until the pH is about 11. From the amount (V) of sodium hydroxide consumed until the neutralization step of the weak acid, where the change in electrical conductivity shows a gradual change, the acid group amount X1 is determined using the following equation.

X1 (mmol / g) = V (mL) × 0.05 / mass of cellulose fiber (g)
The amount of acid groups of the cellulose fiber is preferably 0.1 to 3.0 mmol / g. When the amount of acid groups is less than 0.1 mmol / g, the amount of metal particles present on the surface of the cellulosic fiber is not sufficient in the step of supporting metal ions described later, and the deodorization and antibacterial functions may be inferior. is there. On the other hand, when the amount of acid groups exceeds 3.0 mmol / g, the metal particles may aggregate, and the deodorizing and antibacterial functions may be similarly deteriorated.

  The modification method 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. Examples include oxidation (carboxylation), ether , Phosphorylation, esterification, silane coupling, fluorination, and cationization. In particular, oxidation (carboxylation) and etherification are preferable. Hereinafter, these will be described in detail.

<3-1-1. Oxidation>
In the present invention, the method for oxidizing the cellulosic fibers is not particularly limited, and a known method can be used. An example 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 to produce a group selected from the group consisting of an aldehyde group, a carboxyl group, and a carboxylate group. Although the density | concentration of the cellulose raw material at the time of reaction is not specifically limited, 5 mass% or less is preferable.

  The N-oxyl compound refers to a compound that can generate a nitroxy 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 fiber. For example, 0.01 mmol or more is preferable and 0.02 mmol or more is more preferable with respect to 1 g of absolutely dry cellulose. The upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, and still more preferably 0.5 mmol or less. Accordingly, the amount of N-oxyl compound used is preferably 0.01 to 10 mmol, more preferably 0.01 to 1 mmol, and still more preferably 0.02 to 0.5 mmol with respect to 1 g of absolutely dry cellulose.

  The bromide is a compound containing bromine, and examples thereof include alkali metal bromide that can be dissociated and ionized in water, such as sodium bromide. Further, the iodide is a compound containing iodine, and examples thereof include alkali metal iodide. What is necessary is just to select the usage-amount of a bromide or iodide in the range which can accelerate | stimulate an oxidation reaction. The total amount of bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, with respect to 1 g of absolutely dry cellulose. The upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, and still 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, and still more preferably 0.5 to 5 mmol with respect to 1 g of absolutely dry cellulose.

The oxidizing agent is not particularly limited, and examples thereof include halogen, hypohalous acid, halous acid, perhalogen acid, salts thereof, halogen oxide, and peroxide. In particular, hypochlorous 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 burden.
The amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, and still more preferably 3 mmol or more with respect to 1 g of absolutely 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 used is preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, further preferably 1 to 25 mmol, and most preferably 3 to 10 mmol with respect to 1 g of absolutely dry cellulose.
When the N-oxyl compound is used, the amount of the oxidizing agent used is preferably 1 mol or more with respect to 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 with respect to 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, and more preferably 30 ° C. or lower. Accordingly, 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 more, and more preferably 10 or more. The upper limit is preferably 12 or less, and more preferably 11 or less. Therefore, the pH of the reaction solution is preferably about 8 to 12, more preferably about 10 to 11.
Usually, a carboxyl group is generated in cellulose as the oxidation reaction proceeds, and therefore the pH of the reaction solution tends to decrease. Therefore, in order to advance the oxidation reaction efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution in the above range. The reaction medium for the oxidation is preferably water for reasons such as ease of handling and the difficulty of side reactions.

  The reaction time in the oxidation can be appropriately set according to the progress of the 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 in 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 stages. For example, by oxidizing the oxidized cellulose obtained by filtration after the completion of the first stage reaction again under the same or different reaction conditions, the efficiency is not affected by the reaction inhibition by the salt generated as a by-product in the first stage reaction. Can be oxidized well.

Another example of the carboxylation (oxidation) method is a method of oxidizing by ozone treatment. By this oxidation reaction, at least the 2- and 6-position hydroxyl groups of the glucopyranose ring constituting cellulose are oxidized, and the cellulose chain is decomposed.
The ozone treatment is usually performed by bringing a gas containing ozone and a cellulose raw material into contact with each other. 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, and more preferably 220 g / m 3 or less. 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 amount of ozone added is preferably 0.1 parts by mass or more and more preferably 5% by mass or more with respect to 100% by mass of the solid content of the cellulose raw material. The upper limit is usually 30% by mass or less. Therefore, the amount of ozone added is preferably 0.1 to 30% by mass and more preferably 5 to 30% by mass with respect to 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 to 50 ° C, and more preferably 20 to 50 ° C.
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, and preferably about 30 to 360 minutes.
When the condition of the ozone treatment is within the above range, it is possible to prevent the cellulose from being excessively oxidized and decomposed, and the yield of oxidized cellulose is improved.

  Further, the resulting product obtained after the ozone treatment may be further oxidized using an oxidizing agent. The oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite; oxygen, hydrogen peroxide, persulfuric acid, peracetic acid and the like. Examples of the oxidation treatment method include a method in which these oxidizing agents are dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and the cellulose raw material is immersed in the oxidizing agent solution.

  The amounts of carboxyl groups, carboxylate groups, and aldehyde groups contained in the oxidized cellulose fiber can be adjusted by controlling the oxidizing conditions such as the amount of the oxidizing agent added and the reaction time.

<3-1-2. Etherification>
For the etherification, any method may be used as long as it contains a carboxyl group or a carboxylate group in the functional group after the reaction for the convenience of introducing metal ions into the cellulosic fiber in the subsequent step, and a known method is used. be able to. Examples include carboxymethyl (ether), carboxyethyl (ether), carboxypropyl (ether), carboxybutyl (ether) and other carboxyalkyl etherification, and carboxyphenyl (ether). . As an example, a carboxymethylation method will be described below.

The method of carboxymethylation is not specifically limited, A well-known method can be used. For example, a cellulose raw material as a bottoming raw material is mercerized and then etherified. A common solvent is used in the carboxymethylation reaction. Examples of the solvent include water, alcohol (for example, lower alcohol), and a mixed solvent thereof. Examples of the lower alcohol include methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, 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 to 95% by mass. The amount of the solvent is usually 3 times by mass with respect to the cellulose raw material. Although an upper limit is not specifically limited, It is 20 mass times. Therefore, the amount of the solvent is preferably 3 to 20 times by mass.

  Mercerization is usually performed by mixing a bottoming raw material and a mercerizing agent. Examples of mercerizing agents 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 mol or more, and further preferably 1.5 times mol or more per anhydroglucose residue of the starting material. The upper limit is usually 20 moles or less, preferably 10 moles or less, more preferably 5 moles or less, and more preferably 0.5 to 20 moles, more preferably 1.0 to 10 moles. More preferably 5 to 5 moles.

  The mercerization reaction temperature 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 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 performed 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 usually preferably 0.05 times mol or more, more preferably 0.5 times mol or more, and further preferably 0.8 times mol or more per glucose residue of the cellulose raw material. The upper limit is usually 10.0 times mole or less, preferably 5 moles or less, more preferably 3 times mole or less, and therefore preferably 0.05 to 10.0 times mole, more preferably 0.5 to 5, more preferably 0.8 to 3 times mol.
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. Accordingly, 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 less, preferably 4 hours or less. Therefore, the reaction time is usually 30 minutes to 10 hours, preferably 1 hour to 4 hours.
The reaction solution may be stirred as necessary during the carboxymethylation reaction.

  When the cellulose raw material is modified by carboxymethylation, the degree of carboxymethyl substitution per anhydroglucose unit in the obtained carboxymethylated cellulose fiber is preferably 0.01 or more, more preferably 0.05 or more, and 0.10. More preferably, it is the above. The upper limit is preferably 0.50 or less, more preferably 0.40 or less, and still more preferably 0.35 or less. Accordingly, the degree of carboxymethyl group substitution is preferably 0.01 to 0.50, more preferably 0.05 to 0.40, and still more preferably 0.10 to 0.30.

The degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose fiber can be measured, for example, by the following method. That is, 1) About 2.0 g of carboxymethylated cellulose (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) 100 mL of nitric acid methanol solution obtained by adding 100 mL of special grade concentrated nitric acid to 1000 mL of methanol is added and shaken for 3 hours to convert the carboxymethyl cellulose salt (carboxymethylated cellulose) into hydrogen-type carboxymethylated cellulose. 3) 1.5-2.0 g of hydrogen-type carboxymethylated cellulose (absolutely dry) is precisely weighed and placed in a 300 mL Erlenmeyer flask with a stopper. 4) Wet the hydrogen-type carboxymethylated cellulose with 15 mL of 80% methanol, add 100 mL of 0.1N NaOH, and shake at room temperature for 3 hours. 5) Back titrate excess NaOH with 0.1 N H2SO4 using phenolphthalein as indicator. 6) The degree of carboxymethyl substitution (DS) is calculated by the following formula:
A = [(100 × F ′ − (0.1 N H 2 SO 4) (mL) × F) × 0.1] / (absolute dry mass of hydrogenated carboxymethylated cellulose (g))
DS = 0.162 × A / (1-0.058 × A)
A: 1N NaOH amount (mL) required for neutralizing 1 g of hydrogen-type carboxymethylated cellulose
F ′: 0.1N NaOH factor F: 0.1N H 2 SO 4 factor

<3-2. Metal ion support>
Ion of one or more metal elements selected from the group of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu with respect to cellulosic fibers containing carboxyl groups or carboxylate groups Or by carrying | supporting a nanoparticle, a high deodorizing effect expresses. In particular, by using Ag and Cu, the antibacterial function is further improved.
In the present invention, the metal ions and the cellulosic fibers are chemically bonded to each other, so that when they are contained in the nonwoven fabric, the metal components are not easily detached from the nonwoven fabric, and the mechanical properties such as tensile strength are good. is there.

The method for supporting the metal ions on the cellulosic fiber is not particularly limited. For example, a dispersion of the cellulosic fiber prepared in advance and a metal compound aqueous solution may be mixed. The dispersion liquid may be applied on a substrate to form a film, and the metal compound aqueous solution may be dropped and impregnated into the film. At this time, the film may remain fixed on the substrate or may be peeled from the substrate.
Although details are unknown, when metal ions derived from a metal compound form an ionic bond or coordinate with a carboxylate group or coordinate with these methods, the metal ions are added to the cellulosic fiber. Conceivable.

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. Although the density | concentration of metal compound aqueous solution is not specifically limited, It is preferable that it is the range of 10-80 mass% with respect to 100 mass parts of cellulose fibers, and it is more preferable that it is the range of 30-60 mass%. You may adjust suitably the time which a metal compound is made to contact.
Although the temperature at the time of making it contact is not specifically limited, It is preferable that it is the range of 2-50 degreeC. Further, the pH of the liquid at the time of contacting is not particularly limited. However, when the pH is low, it is difficult for the metal ions to bind to the carboxyl group, and therefore it is preferably in the range of 7 to 13, and in the range of pH 8 to 12. It is particularly preferred.

In the present invention, it is possible to introduce metal ions into the cellulosic fiber as described above, but some of the metal ions may be reduced to form metal nanoparticles. In addition, if necessary, a part of the metal ions bonded to the metal ion-supporting cellulosic fiber can be reduced by adding a reducing agent to form metal nanoparticles partially on the surface of the cellulosic fiber. Is also possible.
However, it is preferable from the viewpoint of the deodorizing effect that the entire amount of the metal compound is used as metal ions without performing a special reduction treatment.

  The fact that the cellulosic fiber contains metal ions can be confirmed by a scanning electron microscope image and ICP emission analysis of the extract with a strong acid. That is, the presence of metal ions cannot be confirmed in the scanning electron microscope image, while it can be confirmed that the metal ions are contained in the ICP emission analysis. On the other hand, for example, when the metal is reduced from ions and exists as metal particles, the metal particles can be confirmed by a scanning electron microscope image, so the presence or absence of metal ions can be determined. The presence or absence of metal ions can also be determined by scanning electron microscope images and element mapping. That is, metal ions cannot be confirmed in a scanning electron microscope image, but the presence of metal ions can be confirmed by elemental mapping.

  In the step of supporting the metal ions, the content of the metal ions with respect to the cellulosic fibers is preferably in the range of 10 to 60 mg / g, more preferably in the range of 15 to 55 mg / g with respect to the cellulosic fibers. A range of 20 to 50 mg / g is particularly preferable. If it is less than 10 mg / g, the deodorizing and antibacterial functions may be inferior. On the other hand, when it exceeds 60 mg / g, aggregation of metal particles occurs, and the deodorizing and antibacterial functions may be inferior as well.

<4. Synthetic fiber>
The nonwoven fabric which concerns on embodiment of this invention contains at least 1 or more types of the fiber which consists of synthetic fibers, ie, the synthetic resin which polymerized organic low molecules, such as petroleum. In general, synthetic fibers are inferior in terms of hygroscopicity, water absorption, flexibility, etc., but superior in terms of dimensional stability, light resistance, etc., compared to the above-described cellulose fibers.
The content of the synthetic fiber is preferably 5% by mass or more based on the nonwoven fabric from the viewpoint of dimensional stability. Moreover, since it is preferable that content of a metal ion containing cellulose fiber is 1 mass% or more with respect to a nonwoven fabric, it is preferable that content of a synthetic fiber is 99 mass% or less with respect to a nonwoven fabric.

  The type of synthetic fiber is not particularly limited, and examples thereof include polyester fibers such as polyethylene terephthalate (PET) fiber, polybutylene terephthalate (PBT) fiber, polyethylene naphthalate (PEN), and polyethylene isophthalate (PEI) fiber, polypropylene ( PP) fiber, polyethylene (PE) fiber, ethylene-vinyl alcohol copolymer fiber, polyolefin fiber such as ethylene-vinyl acetate copolymer fiber, polyacryl fiber, polyamide fiber, polyvinyl alcohol (PVA) fiber, polylactic acid (PLA) fiber, polyester copolymer resin-polyester resin, polyethylene resin-polyester resin, ethylene / vinyl alcohol copolymer resin-polyester resin, polyester copolymer resin-polypropylene resin, poly Styrene resins - polypropylene resins, ethylene-vinyl alcohol copolymer resin - polypropylene resins, ethylene-vinyl acetate copolymer resins - such as composite fibers and polypropylene resin.

<5. Other materials>
In the nonwoven fabric of this invention, you may contain 1 or more types of other materials other than the said metal ion containing cellulose fiber, general cellulose fiber, and a synthetic fiber as needed. Although it does not specifically limit as a kind of other material, For example, stabilizers, such as a heat stabilizer and a weather stabilizer, a filler, an antistatic agent, a slip agent, an antiblocking agent, an antifogging agent, a lubricant, a dye, and a pigment Natural oil, synthetic oil, wax and the like. These may use 1 type and may use 2 or more types together. The total content of these materials is preferably in a range not exceeding 10% by mass with respect to the nonwoven fabric.

  Examples of the stabilizer include anti-aging agents such as 2,6-di-t-butyl-4-methyl-phenol (BHT); tetrakis [methylene-3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate] methane, β- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid alkyl ester, 2,2′-oxamide bis [ethyl-3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate], phenolic antioxidants; fatty acid metal salts such as zinc stearate, calcium stearate, calcium 1,2-hydroxystearate; glycerol monostearate, glycerol distearate, pentaerythritol monostearate Rate, pentaerythritol distearate, pentaerythritol tristearate Polyhydric alcohol fatty acid esters rate, and the like.

  Examples of the filler include silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, sulfuric acid Examples thereof include barium, calcium sulfite, talc, clay, mica, asbestos, calcium silicate, montmorillonite, pentonite, graphite, aluminum powder, and molybdenum sulfide.

Examples of the colorant include inorganic colorants such as titanium oxide and calcium carbonate, and organic colorants such as phthalocyanine.
Examples of the lubricant include oleic acid amide, erucic acid amide, stearic acid amide, and the like.

<6. Nonwoven fabric>
The nonwoven fabric of the present invention forms an accumulation layer of fibers called fleece from the above metal ion-containing cellulose fibers, general cellulose fibers, synthetic fibers, and other materials contained as necessary, It can be produced by bonding and performing processing such as dyeing, laminating, and coating as necessary.

It does not specifically limit as a method of forming a fleece, A well-known method can be used. As an example, a dry method in which dried fibers are formed in a fixed direction or randomly by a machine called card or air flow called airlaid; as in the case of paper production, the fibers are dispersed in water on a net-like net. And a spunbond method in which a melted raw material resin is directly eluted and spun from the tip of a nozzle to form a fleece with continuous long fibers.
In particular, it is preferable to use a wet method because the cellulosic fibers are hydrophilic. In the case of a wet method, it can be manufactured using a conventional papermaking method. As the paper machine, various conventionally known machines such as a circular paper machine, an inclined short paper machine, a long paper machine, a short paper machine, etc. can be used. Can be combined. Examples of the drying step in the papermaking method include a Yankee dryer type, a multi-cylinder type, a hot air type, and an infrared heating type.

  It does not specifically limit as a method to couple | bond fibers, A well-known method can be used. Examples include a chemical bond method in which an adhesive adhesive resin of emulsion type is impregnated or adhered to the fleece by a method such as spraying, and heated and dried to bond the intersections of the fibers; , Thermal bonding method in which fibers are bonded by hot pressing through hot rolls or by applying hot air; fleece is repeatedly pierced with needles that move up and down at high speed, and protrusions called barbs carved into the needles Examples thereof include a needle punch method in which fibers are entangled; a hydroentanglement method in which high-pressure water flow is injected into a fleece in a columnar shape to entangle fibers. In particular, the chemical bond method is preferable.

  The nonwoven fabric in the present invention may have a single layer structure or a multilayer structure. In the case of a multilayer structure, at least one layer needs to contain a cellulosic fiber carrying the metal ions. In the case where the total number of layers is 3 or more, it is preferable that the outermost layer contains cellulosic fibers carrying the metal ions because the deodorizing and antibacterial effects are more easily exhibited.

  The basis weight (basis weight) of the nonwoven fabric is preferably in the range of 10 to 100 g / m2, and more preferably in the range of 20 to 80 g / m2. When the nonwoven fabric has a multilayer structure, the basis weight of each layer is preferably 10 g / m 2 or more from the viewpoint of producing a sheet that is uniform and has a minimum strength in handling during production. In addition, the basis weight of the nonwoven fabric in the present invention means that a nonwoven fabric having an area of 0.05 m2 or more is dried at 105 ° C. until a constant mass is obtained, and then left in a temperature-controlled room at 20 ° C. and 65% RH for 16 hours or more. It refers to the mass (g) per m2 of the measured nonwoven fabric.

  The thickness of the nonwoven fabric is preferably in the range of 20 to 500 μm, and more preferably in the range of 30 to 100 μm. When the nonwoven fabric has a multilayer structure, the thickness of each layer is preferably 20 μm or more from the viewpoint of producing a uniform sheet. The density of the nonwoven fabric is not particularly limited.

  The nonwoven fabric of the present invention can be used as it is, or laminated with a substrate such as another nonwoven fabric and / or subjected to various processing such as embossing and pleating as necessary, and filtered with gas or liquid. It can use suitably for various uses, such as an industrial filter. Other applications include sanitary products such as diapers, sanitary products, wipers, masks, gas or liquid filtration filters, building materials and civil engineering applications such as roofing materials (roofing materials), automobile interior materials, and clothing.

  Hereinafter, although an example is given and the present invention is explained still in detail, the present invention is not limited to these.

<Example 1>
[Manufacture of oxidized cellulose fiber]
Bleached unbeaten kraft pulp derived from conifers (whiteness 85%) 5.00 g (absolutely dried) TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl; Sigma Aldrich) 39 mg (absolutely 1 g) The solution was added to 500 ml of an aqueous solution in which 0.05 mmol of cellulose and 514 mg of sodium bromide (1.0 mmol of 1 g of completely dry cellulose) were dissolved, and stirred until the pulp was uniformly dispersed.
An aqueous sodium hypochlorite solution was added to the reaction system so that sodium hypochlorite was 5.5 mmol / g, and the oxidation reaction was started at room temperature. During the reaction, the pH in the system was lowered, but a 3M sodium hydroxide aqueous solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system no longer changed.
After the reaction mixture was filtered through a glass filter, washing with a sufficient amount of water and filtration were repeated twice to obtain oxidized cellulose fibers impregnated with water having a solid content of 10% by mass. The pulp yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxyl groups was 1.68 mmol / g.

[Supporting metal ions on oxidized cellulose fiber]
After adding water to the above-mentioned oxidized cellulose fiber to obtain a dispersion having a solid concentration of 2% and adjusting the pH to 9.0, CuCl2 (manufactured by Wako Pure Chemical Industries, Ltd.) is added to the oxidized cellulose fiber at a concentration of 1 g. Cu oxide was added to the oxidized cellulose fiber by adding with stirring to 1.0 mmol / g and further stirring for 30 minutes.
In contrast, washing with a sufficient amount of water and filtration were repeated twice to remove unreacted metal salt and to impregnate water with a solid content of 30% by mass and containing Cu ions (containing metal ions). Cellulosic fiber) was obtained.
The content of metal ions with respect to the oxidized cellulose fiber was 31.9 mg / g, and the freeness of the metal ion-containing cellulose fiber was 500 ml.

[Manufacture of non-woven fabric]
Pulp (NBKP with freeness of 600 ml; manufactured by Nippon Paper Industries Co., Ltd.) as a cellulose fiber (general cellulose fiber) containing no metal ions, polyester fiber (product name: Tepyrus TT04N) as a synthetic fiber Cut length 5 mm, manufactured by Teijin Ltd.), wet paper strength agent (product name: WS4020, manufactured by Seiko PMC Co., Ltd.) in a mixing ratio shown in Table 1, and further added water to a solid content concentration of 0.5% by mass An aqueous dispersion was prepared. In Table 1, the blending ratio of each fiber and wet paper strength agent is a value relative to the total amount of all fibers.
This was paper-made with a round hand-making machine, dehydrated with a press machine, and further dried at 85 ° C. with a cylinder dryer to prepare a round nonwoven fabric having a diameter of about 16 cm.

<Example 2>
In the step of supporting metal ions on the oxidized cellulose fiber, the same method as in Example 1 except that the aqueous solution of CuCl2 was changed to an aqueous solution of AgNO3 (concentration per 1 g of oxidized cellulose fiber: 1.0 mmol / g). A non-woven fabric was prepared.
The content of Ag ions relative to the oxidized cellulose fiber was 20.0 mg / g, and the freeness of the metal ion-containing cellulose fiber was 500 ml.

<Example 3>
In the process of manufacturing the nonwoven fabric, the blending ratio of the metal ion-containing cellulosic fibers to the total fiber content is changed from 20% by mass to 50% by mass, and the blending ratio of the cellulosic fibers not containing the metal ions to the total fiber content is 50 A nonwoven fabric was produced in the same manner as in Example 1 except that the mass was changed from 20% by mass to 20% by mass.

<Comparative Example 1>
In the process of manufacturing the nonwoven fabric, the metal ion-containing cellulosic fiber is not blended, and it is replaced with cellulosic fiber that does not contain the same amount of metal ion (NBKP pulp having a freeness of 600 ml, manufactured by Nippon Paper Industries Co., Ltd.). A nonwoven fabric was produced in the same manner as in Example 1.

<Comparative example 2>
In the process of manufacturing the nonwoven fabric, in place of the metal ion-containing cellulosic fiber, except that a commercially available metal (Cu) ion-supported zeolite high-density crystallized pulp (trade name: copper cellgaia, Rengo Co., Ltd.) was blended, A nonwoven fabric was produced in the same manner as in Example 1.

<Comparative Example 3>
A nonwoven fabric was produced in the same manner as in Example 1 except that the oxidized cellulose fiber was not subjected to the treatment of supporting metal ions and the nonwoven fabric was directly contained in the nonwoven fabric.

<Reference example>
The obtained non-woven sheet is impregnated with a 200 ppm reducing agent solution, the filter paper is piled up to remove excess aqueous solution, and dried in a blow dryer at 50 ° C. for 15 minutes to be contained in the metal ion-containing cellulose fiber. A nonwoven fabric was produced in the same manner as in Example 1 except that Cu ions were reduced to Cu nanoparticles.

<Evaluation>
A test piece was prepared from the obtained non-woven fabric, and the test piece was subjected to the following method, deodorizing property, antibacterial property, tensile strength and elongation as mechanical properties, lint as an indicator of fine powder detachment, and filter As performance, air permeability and particle collection rate were evaluated.

[Deodorization]
A gas bag with a cock containing four 5 cm × 5 cm test pieces was filled with 1.5 L of ammonia gas adjusted to 300 ppm at a humidity of 50% with an air pump. Next, the suction tube and the rubber tube were connected to the detection tube, and the rubber tube was connected to the gas bag. And the ammonia gas concentration in the gas bag 50 minutes after filling with air was measured.
◎: Very good Residual concentration is 1/5 or less of the initial value ○: Good Residual concentration is 1/4 or less of the initial value △: Normal Residual concentration is higher than 1/4 of the initial value and 1/3 or less In addition, the same test was performed when ammonia gas with a humidity of 90% adjusted to 500 ppm was used and when 0.5 ml of water was dropped onto the test piece (when wet). Evaluated.
If evaluation is (double-circle), it is excellent in deodorizing property.

[Antimicrobial]
In accordance with JIS L1902, “Antibacterial test method and antibacterial effect of textile products”, a qualitative test by the halo method was performed. Specifically, an agar medium containing Escherichia coli was prepared, a test piece of 5 cm × 5 cm was placed thereon, cultured at 37 ° C. for 17 hours, and the “growth inhibition zone” of the test bacteria formed around the sample. The presence or absence was confirmed. Evaluation was made according to the following criteria.
○: Growth inhibition zone is recognized and has antibacterial properties.
X: No growth inhibition zone was observed and no antibacterial activity was observed.

[Specific tensile strength]
In accordance with JIS L1913 "General nonwoven fabric test method", a test piece having a width of 25 mm and a length of 300 mm was pulled using a constant-speed extension type tensile tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) at a gripping interval of 200 mm and 10 mm / min The specific tensile strength was obtained by applying a load until the test piece was cut, taking the strength at the maximum load as the tensile strength and dividing the measurement result by the basis weight.

[Lint]
A dust generation test was performed in accordance with JIS B9923 (tumbling method), and measurement was performed with a particle counter (product name “KC-01D1” manufactured by Rion). Evaluation was made according to the following criteria. The better the evaluation, the smaller the fall of fine powder such as paper powder and zeolite. If the evaluation is ○, there is no practical problem.
○: Normal ×: Bad

[Breathable]
According to JIS L1913 "General nonwoven fabric test method", it measured by the Gurley method. Specifically, using a Gurley type air permeability tester (manufactured by Toyo Seiki Seisakusho), 10 test pieces of 50 mm x 130 mm are overlaid on the air outlet and tightened. The time (seconds) required for 200 mL of air to be ejected through the specimen with the load generated by the mass was measured.

[Particle collection rate]
In accordance with JIS B9908 “Performance test method of ventilation air filter unit / ventilation electric dust collector”, test method type 3 was carried out. Specifically, 11 types of test powder 1 (Kanto loam, 50% median diameter 2 μm) specified in JIS Z 8901 were used as dust, and the collection efficiency was calculated by the following formula.
Particle collection rate (%) = (1-C2 / C1) × 100
C1: Number of dust on the upstream side of the filter C2: Number of dust on the downstream side of the filter For the calculated results, a case where the result is equal to or greater than that of Comparative Example 1 described later is indicated by ◯, and a case where the result is inferior is indicated by ×. If the evaluation is ○, there is no practical problem.

As is apparent from Table 2, in each of the examples containing metal ion-containing cellulosic fibers and synthetic fibers, the mechanical properties (specific tensile strength) are good, and the deodorization / antibacterial effect is not dependent on humidity but is wet. It was very high even at times.
On the other hand, in the case of the comparative example 1 which did not contain a metal ion containing cellulosic fiber, it was inferior in deodorizing property and mechanical characteristics.
In the case of Comparative Example 2 containing a commercially available metal (Cu) ion-carrying zeolite high-density crystallized pulp instead of the metal ion-containing cellulose fiber, the deodorizing property is inferior to each of the examples, particularly at high humidity and when wet In addition to being inferior in deodorizing property, powder omission occurred.
In the case of Comparative Example 3 in which the oxidized cellulose fiber did not carry metal ions, the deodorizing property was inferior.

Claims (4)

  Contains one or more metal ions selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn, and Cu for cellulosic fibers having carboxyl groups or carboxylate groups on the surface A nonwoven fabric comprising metal ion-containing cellulosic fibers and synthetic fibers.   The nonwoven fabric according to claim 1, wherein in the metal ion-containing cellulosic fiber, a part of the hydroxyl group at the C6 position in the glucose unit of cellulose is oxidized to a carboxyl group.   The nonwoven fabric according to claim 1 or 2, wherein the metal ions are Ag ions or Cu ions.   The nonwoven fabric as described in any one of Claims 1-3 which further contains the cellulosic fiber which does not contain a metal ion.