JP7101493B2 - Wet non-woven fabric - Google Patents

Description

The present invention relates to a wet nonwoven fabric containing a composite of inorganic particles and fibers, and a method for producing the same.

In general, a non-woven fabric is obtained by laminating fibers containing synthetic fibers without weaving and spreading them in a sheet shape, and appropriately bonding the fibers with each other by an appropriate method. Nonwoven fabrics can be mass-produced at low cost because there is no process of spinning, weaving or knitting unlike cloth. In addition, it is easy to adjust various functions such as air permeability due to porosity, filterability, etc., which are the structural features of non-woven fabric, according to the required quality, depending on the raw materials, manufacturing method, and combination with other materials. Is. Due to these characteristics, non-woven fabrics include diapers, sanitary products, sanitary products such as wipers and masks, filters for gas or liquid filtration, building materials and civil engineering applications such as roofing materials (roofing materials), automobile interior materials, clothing, etc. Widely used in various fields.

In the above-mentioned uses of the nonwoven fabric, in addition to the mechanical properties such as tensile strength and tear strength required for the nonwoven fabric in general, deodorant and / or antibacterial functions are often required. For example, in the use of sanitary products such as diapers, it is effective to use malodorous components such as ammonia, trimethylamine, hydrogen sulfide, and methyl mercaptan (urine odor, stool odor, putrefactive odor, etc.), which are the so-called four major malodors. Moreover, it is required to continuously suppress it.

In addition to the appropriate air permeability and particle collection required for filters in general, the filter application has the above-mentioned deodorant function and the growth and growth of mold and hyphae especially when used under high humidity. Effective and continuous suppression is required.

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

Further, in Patent Document 3, after impregnating a fiber structure with a silicon compound and a basic substance-containing aqueous solution and an aluminum compound and a basic substance-containing aqueous solution, the fiber structure is heated by moist heat to heat the silicon compound and aluminum inside the cellulosic fiber. A cellulosic fiber structure that reacts with a compound to form a zeolite that is a porous silica-aluminum body is disclosed. Further, 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 cellulosic fiber containing one or more silver-based antibacterial agents selected from silver zeolite, zirconium silver phosphate, calcium silver phosphate, and silver-soluble glass. Further, a non-woven fabric using this antibacterial cellulosic fiber is disclosed.

Further, Patent Document 5 describes a paper base material containing oxide pulp in which the amount of carboxyl groups of the oxide pulp is 1.0 mmol / g to 2.0 mmol / g with respect to the absolute dry weight of the oxide pulp. A certain paper base material is disclosed, and it is also described that the paper base material contains fibers produced from synthetic resin in a certain range.

In general, hydrotalcite is a general formula [M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] [An- _{x / n} ^· mH2O] (in the formula, M ²⁺ is a divalent metal ion, and M ³⁺ is. A compound represented by a trivalent metal ion, Ann − _{x / n} ^representing an interlayer anion, and 0 <x <1, where n is a valence of A, 0 ≦ m <1). It is one of the substances used as a catalyst, a pharmaceutical, an additive for resin, etc. (Patent Documents 6 to 8, Non-Patent Documents 1 to 3).

Hydrotalcite is a metal hydroxide having a layered crystal structure similar to talcite and smectite, and each crystal piece of hydrotalcite is often leaf-like or scaly. Hydrotalcite includes manasseite, which is a polytype of hydrotalcite, pyroaurite and sjgrenite, whose metals contained in the hydroxide sheet are magnesium and iron, and divalent and trivalent. Green rust, which has iron in the hydroxide sheet, is known. Since the main skeleton is double hydroxide, it is also called layered double hydroxide (LDH). Hydrotalcite is naturally produced, but the amount produced is small, so synthetic products are mainly used, and various synthetic methods are known.

Patent Document 9 proposes a deodorant fabric in which a metal hydroxide such as hydrotalcite is supported on a polyurethane fiber or the like. Further, Non-Patent Document 4 proposes removing phosphorus from wastewater by using hydrotalcite-supporting fibers.

Japanese Unexamined Patent Publication No. 10-120923 Japanese Unexamined Patent Publication No. 11-315492 Japanese Unexamined Patent Publication No. 2008-031591 Japanese Unexamined Patent Publication No. 11-107033 International Publication No. 2014/0997929 Japanese Unexamined Patent Publication No. 2015-193000 Japanese Unexamined Patent Publication No. 2013-085568 Japanese Unexamined Patent Publication No. 2009-143798 Japanese Unexamined Patent Publication No. 2012-144829

"Application of Hydrotalcite to Water Environment Conservation and Purification", The Chemical Times, no. 1, 2005 "Synthesis of Fe-Mg-based and Al-Mg-based hydrotalcite-like compounds and anion exchange properties", J. Ion Exchange, vol. 16, no. 1, 2005 "Surfactant Adsorption Characteristics of Layered Double Hydroxide and Structural Stability of Emulsified Gel", Bulletin of Toyo University, Natural Sciences, No. 56, pp. 43-52, 2012 "Phosphorus removal performance of hydrotalcite-supported fiber (HTCF) from actual wastewater", Journal of Japan Society on Water Environment, vol. 30, no. 11, pp 671-676, 2007

An object of the present invention is to provide a technique for producing an excellent nonwoven fabric from a composite of inorganic particles such as hydrotalcite and fibers by a wet method.

As a result of diligent studies on the above-mentioned problems, the present inventor uses a composite (composite fiber) in which 15% or more of the fiber surface is coated with inorganic particles together with the synthetic fiber, thereby using a high-quality wet type having excellent strength and the like. We have found that a non-woven fabric can be obtained, and have completed the present invention.

That is, the present invention includes, but is not limited to, the following inventions.
(1) A wet nonwoven fabric containing a composite of inorganic particles and fibers and synthetic fibers, wherein 15% or more of the fiber surface of the composite is covered with inorganic particles.
(2) The wet nonwoven fabric according to (1), wherein the average primary particle diameter of the inorganic particles is 1 μm or less.
(3) The wet non-woven fabric according to (1) or (2), wherein the weight ratio of the fiber to the inorganic particles in the complex is 5/95 to 95/5.
(4) The wet nonwoven fabric according to any one of (1) to (3), wherein the fibers constituting the complex are cellulose fibers.
(5) The wet non-woven fabric according to any one of (1) to (4), wherein the cellulose fiber is a pulp derived from wood.
(6) The wet non-woven fabric according to any one of (1) to (5), wherein the inorganic particles are hydrotalcite.
(7) The wet non-woven fabric according to (6), wherein the hydrotalcite has magnesium or zinc as a divalent metal ion.
(8) The wet non-woven fabric according to (6) or (7), wherein the hydrotalcite has aluminum as a trivalent metal ion.
(9) The wet non-woven fabric according to any one of (1) to (8) for use in hygienic products.
(10) The wet non-woven fabric according to any one of (1) to (9) for use in a mask or wiper.
(11) The wet non-woven fabric according to any one of (1) to (10), which is used for deodorizing, antibacterial or antiviral purposes.
(12) The method for producing a wet nonwoven fabric according to any one of (1) to (11), which comprises a step of forming a nonwoven fabric wet from a raw material containing a composite of inorganic particles and fibers and synthetic fibers. , The above method.

According to the present invention, an excellent wet non-woven fabric can be obtained from a complex of inorganic particles and fibers. By appropriately selecting the type of inorganic particles, a wet nonwoven fabric having various properties can be obtained. For example, a wet nonwoven fabric obtained from a composite of hydrotalcite and a fiber has an excellent deodorizing effect and is therefore hygienic. It can be suitably used for supplies and the like.

FIG. 1 is a wet non-woven fabric (Sample 2 of Experiment 1) according to the present invention (14.7 g / m ² , thickness: 51 μm).

The present invention relates to a nonwoven fabric (wet nonwoven fabric) produced by a wet method from a composite (composite fiber) of inorganic particles and fibers. The composite of the inorganic particles and the fibers used in the present invention is a composite fiber whose surface is covered with the inorganic particles. In particular, in the present invention, a fiber / inorganic particle composite in which 15% or more of the fiber surface is covered with inorganic particles is used.

In the composite used in the present invention, the fibers and the inorganic particles are not simply mixed, but the fibers and the inorganic particles are bound by hydrogen bonds or the like, so that the inorganic particles do not easily fall off even by the dissociation treatment or the like. It is a thing.

Wet Nonwoven Fabric The wet nonwoven fabric of the present invention is produced by a wet method from a raw material containing the above-mentioned composite (composite fiber) and synthetic fiber. In the production of the wet nonwoven fabric, a paper strength agent, a binder fiber, a filler (filler) and the like may be further added as needed.

A paper machine can be used to produce the wet non-woven fabric. Examples of the paper machine (paper machine) include a long net paper machine, a circular net paper machine, a gap former, a hybrid former, a multi-layer paper machine, and a known paper machine that combines the paper making methods of these devices. When producing a wet nonwoven fabric, it is possible to make a single-layer papermaking as well as a multi-layer papermaking with two or more layers. In the case of three-layer or more, it is preferable to contain the composite fiber in at least one layer, and for example, it may be blended only in the middle layer. The interlayer strength of the wet nonwoven fabric is, for example, 50 to 150 N / m, preferably 70 to 130 N / m. The measurement of interlayer strength is based on JIS K6854-3: 1994. When the total number of layers is three or more, it is preferable that the outermost layer contains a composite fiber (complex) because effects such as deodorization and antibacterial are more likely to be exhibited.

The method for binding the fibers to each other is not particularly limited, and a known method can be used. As an example, a chemical bond method in which an emulsion-based adhesive resin is impregnated or attached to a sheet by a method such as spraying and then heated and dried to bond the intersections of the fibers; a low melting point heat-fused fiber (binder fiber) is used. Thermal bond method in which fibers are bonded to each other by heat-bonding the mixed sheet through between hot rolls or by applying hot air; the sheet is repeatedly pierced with a needle (needle) that moves up and down at high speed, and is carved into the needle. A needle punch method in which fibers are entwined by a protrusion called a barb; a water flow entanglement method in which a high-pressure water stream is jetted onto a sheet in a columnar shape to entangle the fibers; and the like can be mentioned.

Generally, a wet non-woven fabric sheet is produced by a mixed draft in which cellulosic fibers and synthetic fibers are combined. In that case, since the cellulosic fibers have many hydroxyl groups in their molecules, adhesion based on hydrogen bonds is performed. It is known to develop the physical strength of the sheet. On the other hand, since the synthetic fiber does not have a functional group capable of hydrogen bonding to the molecule, not only the cellulosic fiber and the synthetic fiber do not adhere to each other, but also the synthetic fiber does not adhere to the cellulosic fiber. Intervenes in and inhibits the adhesion, resulting in a decrease in the strength of the sheet.

In the thermal bond method, a thermoplastic synthetic resin fiber is used as a binder fiber (heat fusion fiber), which is mixed with a cellulosic fiber, and the cellulosic fiber and the synthetic fiber are mixed with a high temperature dryer on a papermaking machine. Heat melt to bond the fibers. In this case, the thermoplastic resin fiber is generally a polyethylene terephthalate fiber (hereinafter referred to as polyester fiber), a polypropylene fiber, a polyethylene fiber, a polyolefin synthetic pulp (for example, SWP manufactured by Mitsui Chemicals, etc.), a vinylon fiber (PVA). Fiber) and so on. There are two types of binder fibers, one in which the entire fiber is melted by heat bonding treatment and the other in which only the surface of the fiber is melted. However, the binder fiber may be used properly according to the purpose.

In the chemical bond method, a non-woven fabric is formed using a binder that does not require treatment at a high temperature. As the binder, for example, one or a combination of one or more of polyvinyl alcohol type, polyvinylidene chloride type, acrylonitrile type, ethylene vinyl acetate type, acrylic type and polyvinyl acetate type can be preferably used. The content of the binder resin can be, for example, 3.0 to 20.0% by mass, preferably 4.0 to 15.0% by mass, and more preferably 5. It is 0 to 10.0% by mass.

To attach the binder resin to the non-woven fabric, use a commonly used coating machine such as a roll coater, blade coater, rod coater, air knife coater, gate roll coater, curtain coater, size press coater, shim sizer, or the like. With these coating equipment, it is possible to apply or impregnate a coating liquid containing an external chemical. The coating is on-machine (papermaking / drying of the base paper and coating / drying of the binder resin in succession) and off-machine (papermaking / drying of the base paper, winding, and then secondary winding). It may be either coated or dried).

Further, the wet nonwoven fabric according to one aspect of the present invention may be one in which surface irregularities are provided on one side or both sides of a sheet formed by the above-mentioned method, and for example, embossing or the like can be performed. .. This facilitates impregnation with the liquid. Further, since the specific surface area becomes large due to the unevenness, the contact area with the target portion becomes large, so that various functions such as deodorization and antibacterial can be more easily exhibited.

When producing a wet nonwoven fabric using the composite, various organic substances such as polymers, various inorganic substances such as pigments, and various fibers such as pulp fibers may be added. Further, various organic substances such as polymers, various inorganic substances such as pigments, and various fibers such as pulp fibers may be added to the wet nonwoven fabric later.

As various fibers, for example, cellulose-based fibers can be preferably used, and coniferous bleached kraft pulp (NBKP), unbleached kraft pulp (NUKP), broadleaf bleached kraft pulp (LBKP), and broadleaf bleached kraft. Chemical pulp such as pulp (LUKP), coniferous bleached sulphite pulp (NBSP) or unbleached sulphite pulp (NUSP), broadleaf bleached sulphite pulp (LBSP), broadleaf bleached sulphite pulp (LUSP), or , Grand pulp (GP), Thermomechanical pulp (TMP), Mechanical pulp such as Chemithermomechanical pulp (CTMP, etc.), Deinked pulp (DIP), Non-wood fiber pulp such as cotton and Kenaf, Recycled fiber such as rayon. Can be mentioned. Only one type of these fibers may be blended, or two or more types may be blended in combination.

In order to impart opacity, nonflammability and flame retardancy to the wet nonwoven fabric, a filler may be contained in the range of, for example, 30% by mass or less with respect to the total mass of the wet nonwoven fabric. In that case, it is preferable to use a fired clay as the filler from the viewpoint of opacity, nonflammability and flame retardancy. Other fillers include kaolin, calcined kaolin, delaminated kaolin, clay, delaminated clay, illite, heavy calcium carbonate, light calcium carbonate, light calcium carbonate-silica complex, magnesium carbonate, barium carbonate, etc. Examples thereof include inorganic fillers such as titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide and zinc hydroxide. Depending on the purpose of the wallpaper, these fillers may not be included.

A sizing agent can be used for this wet non-woven fabric in the same manner as ordinary paper. In that case, the sizing agent may be an internal addition or an external addition. Examples of the sizing agent to be used include rosin-based sizing agents, rosin-based binder resin sizing agents, alpha carboxylmethyl-saturated fatty acids and the like, alkyl ketene dimers, alkenyl succinic anhydride, cationic polymer-based sizing agents and the like. In addition, various modified starches such as oxidized starch and enzyme-modified starch, water-soluble binders such as carboxylmethylcellulose and casein, surface paper strength agents, dyes, pigments (clay, kaolin, calcium carbonate, titanium dioxide, etc.) are appropriately used. can do.

The basis weight of the wet non-woven fabric according to one aspect of the present invention may be appropriately selected depending on the intended use and the like. For example, from the viewpoint of sheet strength and the like, the basis weight is preferably 5 g / m ² or more, and 10 g / m. ² or more is more preferable, and 12 g / m ² or more may be used. Further, from the viewpoint of handleability, transportation cost and the like, 120 g / m ² or less is more preferable, 100 g / m ² or less is further preferable, and 80 g / m ² or less or 60 g / m ² or less may be used. When the wet nonwoven fabric has a multi-layer structure, it is preferable that the basis weight of each layer is 10 g / m ² or more from the viewpoint of producing a uniform sheet having the minimum strength in handling at the time of production. The basis weight (grain) of the wet non-woven fabric in the present invention is such that a non-woven fabric having an area of 0.05 m ² or more is dried at 105 ° C. until it reaches a constant mass, and then left in a constant temperature room at 20 ° C. and 65% RH for 16 hours or more. Then, the mass may be measured. The thickness of the nonwoven fabric is preferably in the range of 30 to 250 μm, and may be 35 to 200 μm, 40 to 150 μm, or even 45 to 100 μm. When the nonwoven fabric has a multi-layer structure, it is preferable that the thickness of each layer is 20 μm or more from the viewpoint of producing a uniform sheet. The density of the non-woven fabric is not particularly limited.

Further, in order to effectively exhibit various performances, the specific surface area is preferably 3 m ² / g to 200 m ² / g, more preferably 10 m ² / g to 180 m ² / g. From the same viewpoint, the ash content in the sheet is preferably 3% by weight to 80% by weight, more preferably 10% by weight or more.

The ash content of the wet nonwoven fabric can be adjusted by the amount of inorganic particles contained in the composite and the amount of a filler (hereinafter, also referred to as an internal filler) appropriately added separately from the inorganic particles complexed with the composite. However, it is preferably 20 to 50% by weight. The ash content is a value measured according to JIS P-8251: 2003.

The content of the composite contained in the wet nonwoven fabric is preferably 10% by weight or more and 90% by weight or less, and preferably 20% by weight or more and 80% by weight or less, based on the total weight of the wet nonwoven fabric. Is more preferable, and may be 60% by weight or less or 40% by weight or less. When the content of the complex contained in the wet nonwoven fabric is within the above range, the effect of the present invention can be fully exhibited.

The non-woven fabric of the present invention can be used for various purposes, for example, paper, fiber, cellulose-based composite material, filter material, paint, plastic or other resin, rubber, elastomer, ceramic, glass, tire, building material (asphalt). , Asbestos, cement, boards, concrete, bricks, tiles, plywood, fiberboard, etc.), various carriers (catalyst carrier, pharmaceutical carrier, pesticide carrier, microbial carrier, etc.), excipients (impurity removal, deodorization, dehumidification, etc.), Wrinkle inhibitor, clay, abrasive, modifier, repair material, heat insulating material, moisture-proof material, water-repellent material, water-resistant material, light-shielding material, sealant, shield material, insect repellent, adhesive, ink, cosmetics, medical material , Paste materials, food additives, tablet excipients, dispersants, shape-retaining agents, water-retaining agents, filtration aids, refined oil materials, oil treatment agents, oil modifiers, radio wave absorbers, insulating materials, sound insulation materials, soundproofing Shaking materials, semiconductor encapsulants, radiation blocking materials, cosmetics, fertilizers, feeds, fragrances, additives for paints / adhesives / resins, discoloration inhibitors, conductive materials, heat transfer materials, sanitary goods (disposable diapers, sanitary napkins) , Incontinence pad, breast milk pad), etc. can be widely used for all purposes. Suitable uses of the non-woven fabric according to the present invention include diapers, sanitary products, sanitary products such as wipers and masks, filters for filtering gas or liquid, building materials and civil engineering applications such as roofing materials, automobile interior materials, and the like. Examples include clothing.

Complex of inorganic particles and fibers (composite fiber)
In the present invention, the inorganic particles to be composited with the fiber are not particularly limited, but are preferably water-insoluble or sparingly soluble inorganic particles. Since the synthesis of inorganic particles may be carried out in an aqueous system and the complex may be used in an aqueous system, it is preferable that the inorganic particles are insoluble or sparingly soluble in water.

The inorganic particles referred to here refer to metals or metal compounds. Metal compounds include metal cations (eg, Na ⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Ba ²⁺ , etc.) and anions (eg, O ^2- , ^OH- , CO ₃ ^2- , PO ₄ ³ ). ^- , SO ₄ ^2- , NO _3- , Si ₂ O ₃ ^2- , SiO ₃ ^2- , ^Cl- , ^{F-, S 2- ,} etc.) are bonded by ionic bonds and are generally called inorganic salts. Say. The method for synthesizing these inorganic particles may be either a gas-liquid method or a liquid-liquid method. As an example of the gas-liquid method, there is a carbon dioxide gas method. For example, magnesium carbonate can be synthesized by reacting magnesium hydroxide with carbon dioxide gas. Examples of the liquid method include reacting an acid (hydrochloric acid, sulfuric acid, etc.) with a base (sodium hydroxide, potassium hydroxide, etc.) by neutralization, reacting an inorganic salt with an acid or a base, or combining inorganic salts with each other. There is a method of reacting. For example, barium sulfate can be obtained by reacting barium hydroxide with sulfuric acid, aluminum hydroxide can be obtained by reacting aluminum sulfate with sodium hydroxide, and calcium and aluminum can be obtained by reacting calcium carbonate with aluminum sulfate. Complex inorganic particles can be obtained. Further, when synthesizing the inorganic particles in this way, any metal or metal compound can coexist in the reaction solution. In this case, the metal or the metal compound is efficiently incorporated into the inorganic particles and is composited. Can be transformed into. For example, when phosphoric acid is added to calcium carbonate to synthesize calcium phosphate, titanium dioxide is allowed to coexist in the reaction solution to obtain composite particles of calcium phosphate and titanium.

The complex of the present invention can be obtained by synthesizing inorganic particles in the presence of fibers in one preferred embodiment. This is because the fiber surface provides a suitable field for the precipitation of inorganic particles, so that a complex of inorganic particles and fibers can be easily synthesized.

As one preferred embodiment, the average primary particle size of the inorganic particles in the composite of the present invention can be, for example, less than 1 μm, but the average primary particle size is less than 500 nm or the average primary particle size is less than 200 nm. Inorganic particles of 100 nm or less can be used. Further, the average primary particle diameter of the inorganic particles can be 10 nm or more.

Further, the inorganic particles in the composite of the present invention may take the form of secondary particles in which fine primary particles are aggregated, and secondary particles suitable for the intended use can be generated by an aging step, and by pulverization. It is also possible to make the agglomerates finer. As a crushing method, a ball mill, a sand grinder mill, an impact mill, a high pressure homogenizer, a low pressure homogenizer, a dyno mill, an ultrasonic mill, a kanda grinder, an attritor, a stone mill, a vibration mill, a cutter mill, a jet mill, a breaker, and a beating machine. , Short-screw extruder, twin-screw extruder, ultrasonic stirrer, household juicer mixer and the like.

The strength of the binding of the fiber and the inorganic particles in the composite can be evaluated by a numerical value such as, for example, the ash yield (%), that is, (ash content of the sheet / ash content of the complex before dissociation) × 100. Specifically, the complex is dispersed in water, adjusted to a solid content concentration of 0.2%, dissociated with a standard disintegrator specified in JIS P 820-1: 2012 for 5 minutes, and then according to JIS P 8222: 1998. The ash yield when sheeted using a 150 mesh wire can be used for evaluation. In a preferred embodiment, the ash yield of the complex used in the present invention is 20% by mass or more, more preferably 50% by mass or more.

(Complex of hydrotalcite and fiber)
As an example of the complex used in the wet non-woven fabric of the present invention, a complex of hydrotalcite (HT) and fibers will be described below. This complex has high deodorant properties.

In general, hydrotalcite is [M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] [Ann- _{x / n} ^· mH2O] (in the formula, M ²⁺ is a divalent metal ion and M ³⁺ is a trivalent metal ion. Represents a metal ion of, Ann− _{x / n} ^represents an interlayer anion, and is represented by the general formula of 0 <x <1, where n is the valence of A, 0 ≦ m <1). Here, M ²⁺ , which is a divalent metal ion, is a trivalent metal ion such as Mg ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Ca ²⁺ , Ba ²⁺ , Cu ²⁺ , Mn ²⁺ , etc. An M ³⁺ is, for example, Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Ga ³⁺ , etc., and An-, which is an interlayer anion, has an ^n- value such as OH-, ^{Cl- ,} CO _3- ^, SO _4- ^, etc. Anions can be mentioned, where x is generally in the range 0.2-0.33. Of these, as the divalent metal ion, Mg ²⁺ , Zn ²⁺ , Fe ²⁺ , and Mn ²⁺ are preferable. The crystal structure has a laminated structure consisting of a two-dimensional basic layer in which the brucite units of a regular octahedron having a positive charge are lined up and an intermediate layer having a negative charge.

Hydrotalcite has been used for various applications utilizing its anion exchange function, for example, for ion exchange materials, adsorbents, deodorants and the like. In addition, by utilizing the combination of constituent metal ions and heating and dehydrating hydrotalcite in which each constituent metal ion is in a good mixed state, or by further heating and calcining, a composite oxide having a uniform composition can be easily obtained. There are also examples of its use in catalyst applications.

The ratio of hydrotalcite in the complex of the present invention can be 10% or more, 20% or more, and preferably 40% or more. The ash content of the complex of hydrotalcite and fiber can be measured according to JIS P 8251: 2003. In the present invention, the ash content of the complex of hydrotalcite and the fiber can be 10% or more, 20% or more, and preferably 40% or more. Further, the complex of the hydrotalcite and the fiber of the present invention preferably contains magnesium, iron, manganese or zinc in an ash content of 10% or more, and more preferably 40% or more. The content of magnesium or zinc in the ash can be quantified by X-ray fluorescence analysis.

The present invention relates to a complex of hydrotalcite and fiber, but in a preferred embodiment, 15% or more of the fiber surface is covered with hydrotalcite. In a preferred embodiment, the composite of the present invention has a fiber coverage (area ratio) of 25% or more, more preferably 40% or more, but a coverage of 60% or more according to the present invention. It is also possible to produce a complex of 80% or more. Further, in the composite of hydrotalcite and fiber according to the present invention, in a preferred embodiment, it is possible that the hydrotalsite is not only fixed on the outer surface of the fiber or inside the lumen, but also generated on the inside of the microfibril. It is clear from the results of microscopic observation.

When hydrotalcite and fibers are complexed according to the present invention, not only is hydrotalcite easier to yield to the product, but also hydrotalcite is uniformly dispersed without agglomeration, as compared with the case where hydrotalcite is simply mixed with fibers. You can get the product. That is, according to the present invention, the yield of the composite of hydrotalcite and fiber (the weight ratio of the charged hydrotalcite remaining in the product) can be 65% or more, and 70% or more. It can also be 85% or more.

(Synthesis of hydrotalcite and fiber composite)
In the present invention, a composite of hydrotalcite and fiber is produced by synthesizing hydrotalcite in solution in the presence of fiber.

The method for synthesizing hydrotalcite can be a known method. For example, a fiber is immersed in a carbonate aqueous solution containing carbonate ions constituting an intermediate layer and an alkaline solution (sodium hydroxide, etc.) in a reaction vessel, and then an acid solution (divalent metal ions and trivalents constituting the basic layer) is immersed. A metal salt solution containing metal ions) is added, and the temperature, pH, etc. are controlled to synthesize hydrotalcite by a co-precipitation reaction. Further, in the reaction vessel, the fiber is immersed in an acid solution (a metal salt aqueous solution containing divalent metal ions and trivalent metal ions constituting the basic layer), and then a carbonate aqueous solution containing carbonate ions constituting the intermediate layer. And an alkaline solution (sodium hydroxide, etc.) can be added dropwise to control the temperature, pH, etc., and hydrotalcite can be synthesized by a co-precipitation reaction. Although the reaction under normal pressure is common, there is also a method of obtaining it by a hydrothermal reaction using an autoclave or the like (Japanese Patent Laid-Open No. 60-6619).

In the present invention, various chlorides, sulfides, glass oxides, and sulfates of magnesium, zinc, barium, calcium, iron, copper, cobalt, nickel, and manganese are used as sources of divalent metal ions constituting the basic layer. Can be used. Further, as a source of trivalent metal ions constituting the basic layer, various chlorides, sulfides, glass oxides and sulfates of aluminum, iron, chromium and gallium can be used.

In the present invention, water is used for preparing a suspension, and as this water, ordinary tap water, industrial water, groundwater, well water, etc. can be used, as well as ion-exchanged water, distilled water, and super water. Pure water, industrial wastewater, and water obtained during the manufacturing process can be preferably used.

In the present invention, carbonate ion, nitrate ion, chloride ion, sulfate ion, phosphate ion and the like can be used as the interlayer anion. When carbonate ions are used as interlayer anions, sodium carbonate is used as a source. However, sodium carbonate can be replaced with a gas containing carbon dioxide (carbon dioxide gas), and may be a substantially pure carbon dioxide gas or a mixture with other gases. For example, exhaust gas discharged from an incinerator, a coal boiler, a heavy oil boiler, or the like in a paper mill can be suitably used as a carbon dioxide-containing gas. In addition, a carbonation reaction can be carried out using carbon dioxide generated from the lime firing step.

When producing the complex of the present invention, various known auxiliaries can be further added. For example, a chelating agent can be added to the neutralization reaction, specifically polyhydroxycarboxylic acids such as citric acid, malic acid, tartaric acid, dicarboxylic acids such as oxalic acid, sugar acids such as gluconic acid, iminoni. Aminopolycarboxylic acids such as acetic acid and ethylenediamine tetraacetic acid and their alkali metal salts, alkali metal salts of polyphosphates such as hexametaphosphate and tripolyphosphate, amino acids such as glutamate and aspartic acid and their alkali metal salts, acetylacetone and acetoacetic acid. Examples thereof include ketones such as methyl and allyl acetoacetate, saccharides such as sucrose, and polyols such as sorbitol. In addition, as a surface treatment agent, saturated fatty acids such as palmitic acid and stearic acid, unsaturated fatty acids such as oleic acid and linoleic acid, resinous acids such as alicyclic carboxylic acid and avietinic acid, salts, esters and ethers thereof, and alcohol-based agents. Activators, sorbitan fatty acid esters, amide-based and amine-based surfactants, polyoxyalkylene alkyl ethers, polyoxyethylene nonylphenyl ether, sodium alphaolefin sulfonate, long-chain alkyl amino acids, amine oxides, alkylamines, fourth A tertiary ammonium salt, an aminocarboxylic acid, a phosphonic acid, a polyvalent carboxylic acid, a condensed phosphoric acid and the like can be added. Further, a dispersant can also be used if necessary. Examples of the dispersant include sodium polyacrylic acid, sucrose fatty acid ester, glycerin fatty acid ester, acrylic acid-maleic acid copolymer ammonium salt, methacrylic acid-naphthoxypolyethylene glycol acrylate copolymer, and methacrylic acid-polyethylene glycol. There are monomethacrylate copolymer ammonium salt, polyethylene glycol monoacrylate and the like. These can be used alone or in combination of two or more. Further, the timing of addition may be before or after the neutralization reaction. Such additives can be added in an amount of preferably 0.001 to 20%, more preferably 0.1 to 10%, based on hydrotalcite.

(Reaction condition)
In the present invention, the temperature of the synthesis reaction can be, for example, 30 to 100 ° C, preferably 40 to 80 ° C, more preferably 50 to 70 ° C, and particularly preferably about 60 ° C. If the temperature is too high or too low, the reaction efficiency tends to decrease and the cost tends to increase.

Further, in the present invention, the neutralization reaction can be a batch reaction or a continuous reaction. In general, it is preferable to carry out a batch reaction step because of the convenience of discharging the residue after the neutralization reaction. The scale of the reaction is not particularly limited, but the reaction may be carried out on a scale of 100 L or less, or may be reacted on a scale of more than 100 L. The size of the reaction vessel may be, for example, about 10 L to 100 L, or may be about 100 L to 1000 L.

Furthermore, the neutralization reaction can be controlled by monitoring the pH of the reaction suspension, reaching, for example, below pH 9, preferably below pH 8, more preferably around pH 7, depending on the pH profile of the reaction. The neutralization reaction can be carried out until the pH is increased.

Furthermore, the synthesis reaction can be controlled by the reaction time, and specifically, the time during which the reaction product stays in the reaction vessel can be adjusted and controlled. In addition, in the present invention, the reaction can be controlled by stirring the reaction solution in the reaction vessel or by making the neutralization reaction a multi-step reaction.

In the present invention, since the complex as a reaction product is obtained as a suspension, it is stored in a storage tank and treated with concentration, dehydration, pulverization, classification, aging, dispersion and the like, if necessary. Can be done. These can be performed by a known process, and may be appropriately determined in consideration of the application, energy efficiency, and the like. For example, the concentration / dehydration treatment is performed using a centrifugal dehydrator, a sedimentation concentrator, or the like. Examples of this centrifugal dehydrator include a decanter, a screw decanter, and the like. There is no particular limitation on the type of filter or dehydrator, and general ones can be used. For example, a pressurized dehydrator such as a filter press, a drum filter, a belt press, or a tube press can be used. A calcium carbonate cake can be obtained by preferably using a vacuum drum dehydrator such as an Oliver filter. As a crushing method, a ball mill, a sand grinder mill, an impact mill, a high pressure homogenizer, a low pressure homogenizer, a dyno mill, an ultrasonic mill, a kanda grinder, an attritor, a stone mill, a vibration mill, a cutter mill, a jet mill, a breaker, and a beating machine. , Short-screw extruder, twin-screw extruder, ultrasonic stirrer, household juicer mixer and the like. Examples of the classification method include a sieve such as a mesh, an outward type or inward type slit or a round hole screen, a vibration screen, a heavy foreign matter cleaner, a lightweight foreign matter cleaner, a reverse cleaner, and a sieving tester. Examples of the dispersion method include a high-speed disperser and a low-speed kneader.

The complex obtained by the present invention can be blended in a filler or a pigment in a suspension state without being completely dehydrated, or can be dried into a powder. The dryer in this case is also not particularly limited, but for example, an air flow dryer, a band dryer, a spray dryer and the like can be preferably used.

The complex obtained by the invention can be intercalated with chloride ions, nitrate ions and the like as interlayer ions by treating with a weak acid such as dilute hydrochloric acid or dilute nitric acid. Examples of the intercalating compound include anionic substances, and examples thereof include a thiosulfato complex of copper or silver, copper chloride, silver chloride, copper nitrate, silver nitrate and the like. As a method of intercalation, a known method can be used, but a solution containing an anionic substance can be added to the complex of hydrotalcite and the fiber and mixed. Further, a solution containing a cationic substance such as copper chloride, silver chloride, copper nitrate and silver nitrate can be added to the composite of hydrotalcite and fiber to treat the surface of the composite. By these methods, copper or silver can be attached to the complex, and antibacterial properties and antiviral properties can be imparted.

Further, the complex obtained by the present invention can be modified by a known method. For example, in some embodiments, the surface can be made hydrophobic to improve miscibility with a resin or the like.

(Fibers that make up the complex)
In the present invention, inorganic particles and fibers are complexed. The fibers constituting the composite are not particularly limited, but for example, natural fibers such as cellulose, synthetic fibers artificially synthesized from raw materials such as petroleum, and recycled fibers (semi-synthetic fibers) such as rayon and lyocell. ), Furthermore, inorganic fibers such as ceramics can be used without limitation. In addition to the above, natural fibers include protein-based fibers such as wool, silk thread and collagen fiber, and composite sugar chain-based fibers such as chitin / chitosan fiber and alginate fiber.

Examples of the cellulose-based raw material include pulp fibers (wood pulp and non-wood pulp) and bacterial cellulose, and wood pulp may be produced by pulping the wood raw material. Wood raw materials include red pine, black pine, todo pine, ezo pine, beni pine, larch, fir, tsuga, sugi, hinoki, larch, shirabe, spruce, hiba, douglas fur, hemlock, white fur, spruce, balsam fur, cedar, pine, Coniferous trees such as merkushimatsu and radiata pine, and their mixed materials, beech, hippo, hannoki, nara, tab, shii, white hippo, hakoyanagi, poplar, tamo, doroyanagi, eucalyptus, mangrove, lauan, acacia and other broadleaf trees and their mixture. The material is exemplified.

The method for pulping a wood raw material is not particularly limited, and examples thereof include a pulping method generally used in the paper industry. Wood pulp can be classified by the pulping method, for example, chemical pulp distilled by a method such as craft method, sulfite method, soda method, polysulfide method; mechanical pulp obtained by pulping by mechanical force such as refiner, grinder, etc .; chemicals. Examples thereof include semi-chemical pulp; used paper pulp; and deinked pulp obtained by pulping by mechanical force after pretreatment with. The wood pulp may be in an unbleached state (before bleaching) or in a bleached state (after bleaching).

Examples of non-wood-derived raw materials include cotton, hemp, sisal hemp, Manila hemp, flax, straw, bamboo, bagasse, kenaf, sugar cane, corn, rice straw, kozo, and honey.

The pulp fiber may be unbeaten or beaten, and may be selected according to the physical characteristics of the complex sheet, but it is preferable to beat the pulp fiber. This can be expected to improve the sheet strength and promote the fixation of calcium carbonate.

Synthetic fibers include polyester, polyamide, polyolefin, acrylic, nylon, acrylic, vinylon, ceramic fibers, etc., semi-synthetic fibers include rayon, acetate, etc., and inorganic fibers include glass fibers, carbon fibers, various metal fibers, etc. Can be mentioned.

Further, these cellulose raw materials are further treated to obtain powdered cellulose, chemically modified cellulose such as oxidized cellulose, and cellulose nanofibers: CNF (microfibrillated cellulose: MFC, TEMPO oxidized CNF, phosphate esterified CNF, carboxymethylated). It can also be used as CNF, machine crushing CNF, etc.). The powdered cellulose used in the present invention has a constant particle size in the shape of a rod shaft, which is produced by, for example, purifying and drying an undecomposed residue obtained after acid-hydrolyzing selected pulp, pulverizing and sieving. A crystalline cellulose powder having a distribution may be used, or commercially available products such as KC Flock (manufactured by Nippon Paper Co., Ltd.), Theoras (manufactured by Asahi Kasei Chemicals Co., Ltd.), and Abyssel (manufactured by FMC) may be used. The degree of polymerization of cellulose in powdered cellulose is preferably about 100 to 1500, the degree of crystallinity of powdered cellulose by the X-ray diffraction method is preferably 70 to 90%, and the volume average particle diameter by a laser diffraction type particle size distribution measuring device. Is preferably 1 μm or more and 100 μm or less. The cellulose oxide used in the present invention can be obtained by oxidizing in water with an oxidizing agent in the presence of, for example, an N-oxyl compound and a compound selected from the group consisting of bromide, iodide or a mixture thereof. can. As the cellulose nanofiber, the method of defibrating the cellulose raw material is used. As a defibration method, for example, an aqueous suspension of chemically modified cellulose such as cellulose or oxidized cellulose is mechanically ground or beaten with a refiner, a high-pressure homogenizer, a grinder, a uniaxial or multiaxial kneader, a bead mill or the like. Thereby, a method of defibrating can be used. Cellulose nanofibers may be produced by combining one or more of the above methods. The fiber diameter of the produced cellulose nanofibers can be confirmed by observation with an electron microscope or the like, and is, for example, in the range of 5 nm to 1000 nm, preferably 5 nm to 500 nm, and more preferably 5 nm to 300 nm. When producing the cellulose nanofibers, before and / or after the cellulose is defibrated and / or finely divided, an arbitrary compound may be further added and reacted with the cellulose nanofibers to modify the hydroxyl group. can. Functional groups to be modified include acetyl group, ester group, ether group, ketone group, formyl group, benzoyl group, acetal, hemiacetal, oxime, isonitrile, allen, thiol group, urea group, cyano group, nitro group and azo group. , Aryl group, aralkyl group, amino group, amide group, imide group, acryloyl group, methacryloyl group, propionyl group, propioloyl group, butyryl group, 2-butyryl group, pentanoyl group, hexanoyl group, heptanoyle group, octanoyl group, nonanoyl group. , Decanoyl group, undecanoyl group, dodecanoyl group, myristoyl group, palmitoyl group, stearoyl group, pivaloyl group, benzoyl group, naphthoyl group, nicotinoyyl group, isonicotinoyl group, floyl group, cinnamoyl group and other acyl groups, 2-methacryloyloxyethyl isothia Isocyanate group such as noyl group, methyl group, ethyl group, propyl group, 2-propyl group, butyl group, 2-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl. Examples thereof include an alkyl group such as a group, an undecyl group, a dodecyl group, a myristyl group, a palmityl group and a stearyl group, an oxylan group, an oxetane group, an oxyl group, a thiilan group and a thietan group. Hydrogen in these substituents may be substituted with a functional group such as a hydroxyl group or a carboxyl group. Further, a part of the alkyl group may have an unsaturated bond. The compound used for introducing these functional groups is not particularly limited, and is, for example, a compound having a phosphate-derived group, a compound having a carboxylic acid-derived group, a compound having a sulfuric acid-derived group, or a sulfonic acid-derived compound. Examples thereof include a compound having a group of, a compound having an alkyl group, a compound having a group derived from an amine, and the like. The compound having a phosphoric acid group is not particularly limited, and examples thereof include phosphoric acid, lithium dihydrogen phosphate which is a lithium salt of phosphoric acid, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, and lithium polyphosphate. .. Further, examples thereof include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, and sodium polyphosphate, which are sodium salts of phosphoric acid. Further, potassium dihydrogen phosphate, which is a potassium salt of phosphoric acid, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate can be mentioned. Further, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, ammonium polyphosphate, which are ammonium salts of phosphoric acid, and the like can be mentioned. Of these, phosphoric acid, a sodium salt of phosphoric acid, a potassium salt of phosphoric acid, and an ammonium salt of phosphoric acid are preferable, and sodium dihydrogen phosphate is preferable from the viewpoint of high efficiency of introducing a phosphoric acid group and easy industrial application. , Disodium hydrogen phosphate is more preferred, but is not particularly limited. The compound having a carboxyl group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. .. The acid anhydride of the compound having a carboxyl group is not particularly limited, and examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. Be done. The derivative of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of an acid anhydride of a compound having a carboxyl group and a derivative of an acid anhydride of a compound having a carboxyl group. The imide of the acid anhydride of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of a dicarboxylic acid compound such as maleimide, succinic acidimide, and phthalic acidimide. The derivative of the acid anhydride of the compound having a carboxyl group is not particularly limited. For example, at least a part of the hydrogen atom of the acid anhydride of a compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc., is a substituent (for example, an alkyl group, a phenyl group, etc.). ) Is substituted. Among the compounds having a group derived from the carboxylic acid, maleic anhydride, succinic anhydride, and phthalic anhydride are preferable because they are easily applied industrially and easily gasified, but are not particularly limited. Further, the cellulose nanofibers may be modified in such a manner that the modifying compound physically adsorbs to the cellulose nanofibers without chemically binding. Examples of the compound that is physically adsorbed include a surfactant and the like, and any of anionic, cationic and nonionic compounds may be used. If the above modification is performed before the cellulose is defibrated and / or pulverized, these functional groups can be desorbed and returned to the original hydroxyl group after the defibration and / or pulverization. By applying the above modifications, it is possible to promote the defibration of the cellulose nanofibers and facilitate the mixing with various substances when the cellulose nanofibers are used.

The fibers shown above may be used alone or in combination of two or more. Among them, it is preferable to contain wood pulp or a combination of wood pulp and non-wood pulp and / or synthetic fiber, and more preferably only wood pulp.

In a preferred embodiment, the fibers constituting the complex of the present invention are pulp fibers. Further, for example, the fibrous substance recovered from the wastewater of a paper mill may be used in the present invention. By supplying such a substance to the reaction vessel, various composite particles can be synthesized, and fibrous particles and the like can be synthesized in terms of shape.

Synthetic fiber Examples of the synthetic fiber used in the present invention include polyester, polyamide fiber such as nylon and aramid, polyolefin fiber, polyurethane fiber, acrylic fiber, polyvinyl alcohol fiber, vinylon, vinylidene, polyvinyl chloride and the like. Examples of the polyolefin fiber include polyethylene fiber and polypropylene fiber, and examples of polyethylene include high-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, linear low-density polyethylene, and ultra-high-molecular-weight polyethylene. Be done. Examples of the polyester fiber include polyethylene terephthalate (PET) fiber, polytrimethylene terephthalate (PTT) fiber, polybutylene terephthalate (PBT) fiber and the like. Examples of the polyamide fiber include nylon fiber and aramid fiber. As the synthetic fiber used in the present invention, it is preferable to use a polyester-based, polypropylene-based, or polyethylene-based synthetic fiber from the viewpoint of mixing property with the composite (composite fiber) and papermaking property (water squeezing, texture). Is. In particular, when considering the mixing property, it is preferable to use polyester-based synthetic fibers.

Further, the synthetic fiber may be an independent fiber having a single concentric structure, or may be a core-sheath type fiber having different melting points of the core portion and the sheath portion. In a preferred embodiment, the synthetic fiber has a fineness of 0.5 to 4.5 dtex and a fiber length of 3 to 30 mm (preferably 5 to 20 mm, more preferably 5 to 15 mm) from the viewpoint of fiber dispersibility. desirable. The measurement of the fineness and fiber length of this synthetic fiber is based on JIS L 1015: 2010. The melting point of the synthetic fiber is, for example, in the range of 110 to 300 ° C., preferably in the range of 110 to 280 ° C., and is 200 in consideration of high temperature treatment such as embossing under high temperature in the subsequent stage and stability. More preferably, it is in the range of about 260 ° C. When the melting point is as low as less than 110 ° C., stains (fluffing) derived from synthetic fibers are likely to occur in the papermaking dryer when the base paper of the wet non-woven fabric is made. On the other hand, blending synthetic fibers having a melting point of more than 300 ° C. is not only technically meaningless but also uneconomical. When using a core-sheath type synthetic fiber, select one having a melting point of the sheath within the above range. The measurement of the melting point of the synthetic fiber is based on JIS K 7121: 2012.

A binder may be used if necessary. Examples of the binder include heat-sealing fibers and hot water-soluble fibers. Examples of the heat-sealing fiber include a core-sheath type polyester-based composite fiber, a polyethylene terephthalate (PET) fiber, a core-sheath type polyolefin-based composite fiber, and a pulp-like multi-branched fiber having hydrophilicity. Examples of the core-sheath type polyester-based composite fiber include a composite fiber (core-sheath fiber) in which the sheath portion (low melting point component) is made of modified polyester and the core portion (high melting point component) is made of polyethylene terephthalate. Examples of the core-sheath type polyolefin-based composite fiber include a composite fiber (core-sheath fiber) in which the sheath portion (low melting point component) is made of polyethylene and the core portion (high melting point component) is made of polypropylene. Further, the pulp-like multi-branched fiber having hydrophilicity is also referred to as polyolefin synthetic pulp, and examples thereof include those commercially available from Mitsui Chemicals, Inc. under the trade name of SWP. Hot water-soluble fibers are almost insoluble in water at room temperature and maintain their fiber morphology, but when heated on the dryer surface after papermaking, they begin to dissolve easily, and then re-solidify and become strong in dehydration drying. A fiber that constitutes a paper layer. Examples of the hot water-soluble fiber used in the present invention include a polyvinyl alcohol-based fibrous binder. This is usually a short cut of polyvinyl alcohol fiber, which only swells in water at room temperature and does not dissolve, but dissolves in warm water at 60 to 90 ° C. and functions as a binder.

In addition to synthetic fibers, natural fibers such as cellulose fibers, protein-based fibers such as wool, silk thread and collagen fibers, chitin / chitosan fibers, and arginic acid fibers may be blended, if necessary. Preferred natural fibers are cellulose fibers, for example, chemically modified celluloses such as chemical pulps, mechanical pulps, semi-chemical pulps, used paper pulps, deinked pulps, powdered celluloses, oxidized celluloses, and cellulose nanofibers: CNF (microfibrillation). Cellulose: MFC, TEMPO oxide CNF, phosphate esterified CNF, carboxymethylated CNF, machine pulverized CNF, etc.), and the like.

Other Materials The wet nonwoven fabric of the present invention may contain components other than those described above. For example, a wet paper strength agent (paper strength enhancer) can be added. Thereby, the wet strength of the wet nonwoven fabric can be improved. Examples of the wetting paper strength agent include urea formaldehyde resin, melamine formaldehyde resin, polyamide / polyamine / epichlorohydrin resin, vegetable gum, latex, polyethyleneimine, glyoxal, gum, mannogalactan polyethyleneimine resin, and polyacrylamide resin. , Polyvinylamine resin, resin such as polyvinyl alcohol; composite polymer or copolymer polymer composed of two or more kinds selected from the above resins; starch and processed starch; carboxymethyl cellulose, guar gum, urea resin and the like. When a wet paper force agent is further added to the composite, the wet paper force agent may be further added to the slurry obtained after the composite is produced, and then papermaking may be performed. The content of the wetting paper strength agent can be appropriately adjusted according to the use of the wet non-woven fabric, but in order to exert the effect more preferably, for example, 0.1 to 0.1 to the weight of the composite. It is preferably 1.0% by weight, more preferably 0.3 to 0.7% by weight.

In addition to the composite and synthetic fibers, the wet nonwoven fabric of the present invention may contain one or more other materials, if necessary. The types of other materials are not particularly limited, but are, for example, stabilizers such as heat-resistant stabilizers and weather-resistant stabilizers, fillers, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, and pigments. , Natural oil, synthetic oil, wax and the like. These may be used alone or in combination of two or more. The total content of these materials is preferably in the range not exceeding 10% by mass with respect to the wet nonwoven fabric.

Stabilizers include, for example, 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'-oxamidbis [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; glycerin monostearate, glycerin distearate, pentaerythritol monosteer Examples thereof include polyhydric alcohol fatty acid esters such as rate, pentaerythritol distearate, and pentaerythritol tristearate.

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

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

Further, a high molecular polymer or an inorganic substance can be added in order to promote the fixing of the filler to the fiber or to improve the yield of the filler or the fiber. For example, as the coagulant, polyethyleneimine and modified polyethyleneimine containing a tertiary and / or quaternary ammonium group, polyalkyleneimine, dicyandiamide polymer, polyamine, polyamine / epiclohydrin polymer, and dialkyldiallyl quaternary ammonium monomer, dialkyl. Aminoalkyl acrylates, dialkylaminoalkylmethacrylates, dialkylaminoalkylacrylamides, dialkylaminoalkylmethacrylate and acrylamide polymers, polymers consisting of monoamines and epihalohydrin, polymers with polyvinylamine and vinylamine moieties, and cations such as mixtures thereof. In addition to the sex polymer, a cation-rich amphoteric polymer in which an anionic group such as a carboxyl group or a sulfone group is copolymerized in the molecule of the polymer, or a mixture of a cationic polymer and an anionic or amphoteric polymer is used. be able to. Further, as the retention agent, a cationic or anionic or amphoteric polyacrylamide-based substance can be used. In addition to these, a yield system called a so-called dual polymer, in which at least one kind of cation or anionic polymer is used in combination, can be applied, and at least one kind of anionic bentonite, colloidal silica, polysilicic acid, etc. can be applied. It is a multi-component yield system that uses one or more of inorganic fine particles such as polysilicic acid or polysilicate microgels and their aluminum modifiers, and organic fine particles with a particle size of 100 μm or less, which are so-called micropolymers cross-linked and polymerized with acrylamide. May be good. In particular, when the polyacrylamide-based substance used alone or in combination has a weight average molecular weight of 2 million daltons or more by the extreme viscosity method, a good yield can be obtained, preferably 5 million daltons or more, more preferably. Can obtain a very high yield when it is the above-mentioned acrylamide-based substance of 10 million daltons or more and less than 30 million daltons. The form of this polyacrylamide-based substance may be an emulsion type or a solution type. The specific composition is not particularly limited as long as the substance contains an acrylamide monomer unit as a structural unit, but for example, a copolymer of a quaternary ammonium salt of an acrylic acid ester and acrylamide, or acrylamide. An ammonium salt quaternized after copolymerizing with and an acrylate ester can be mentioned. The cationic charge density of the cationic polyacrylamide-based substance is not particularly limited.

In addition, depending on the purpose, inorganic particles such as drainage improver, internal sizing agent, pH adjuster, defoaming agent, pitch control agent, slime control agent, bulking agent, calcium carbonate, kaolin, talc, silica, etc. (so-called) Filling fee) and the like. The amount of each additive used is not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to such examples. Further, unless otherwise specified in the present specification, the concentration, parts and the like are based on weight, and the numerical range is described as including the end points thereof.

Experiment 1: Production of wet non-woven fabric (1) Synthesis of hydrotalcite and fiber composite A solution for synthesizing hydrotalcite (HT) was prepared. As an alkaline solution, a mixed aqueous solution (solution A) of Na ₂ CO ₃ (Wako Pure Chemical Industries, Ltd.) and NaOH (Wako Pure Chemical Industries, Ltd.) was prepared. Further, as an acid solution, a mixed aqueous solution (B solution) of ZnCl ₂ (Wako Pure Chemical Industries, Ltd.) and AlCl ₃ (Wako Pure Chemical Industries, Ltd.) was prepared.
-Alkaline solution (A solution, Na ₂ CO ₃ concentration: 0.05 M, NaOH concentration: 0.8 M)
-Acid solution (B solution, ZnCl ₂ concentration: 0.3M, AlCl ₃ concentration: 0.1M)
Cellulose fiber was used as the raw material fiber. Specifically, it contains broad-leaved bleached kraft pulp (LBKP, manufactured by Nippon Paper Industries) and coniferous bleached kraft pulp (NBKP, manufactured by Nippon Paper Industries) in a weight ratio of 8: 2, and uses a single disc refiner (SDR) to perform Canadian standard drainage. Pulp fibers adjusted in degree to 390 ml were used.

Pulp fibers were added to the alkaline solution to prepare an aqueous suspension containing the pulp fibers (pulp fiber concentration: 1.56%, pH: about 12.4). This aqueous suspension (pulp solid content 30 g) is placed in a 10 L reaction vessel, and an acid solution (B solution) is dropped while stirring the aqueous suspension to form a complex of hydrotalcite fine particles and fibers. Synthesized. The reaction temperature was 50 ° C., the dropping rate was 5 to 15 ml / min, and dropping was stopped when the pH of the reaction solution reached about 7 to 8. After completion of the dropping, the reaction solution was stirred for 30 minutes to obtain a Zn-based HT composite (Zn ₆ Al ₂ (OH) ₁₆ CO _{3.4H 2} O and pulp fiber composite).

Further, the Zn-based HT complex was treated with a copper chloride solution to obtain a Zn-based HT complex carrying copper. Specifically, an acid solution prepared by dissolving copper chloride was added to the Zn-based HT complex slurry (concentration: 1.56%) so that the amount of copper per solid content was 2.0%. The mixture was stirred for 3 hours at 50 ° C. After this treatment, the salt was removed by washing with water using 3 times the amount of water.

(2) Evaluation of complex A mat was produced from the synthesized Zn-based HT composite based on JIS P 8222 (basis weight: about 100 g / m ² ). Specifically, the aqueous slurry (about 0.5%) of the Zn-based HT complex was filtered using a filter paper (JIS P3801, for quantitative analysis, type 5 B), and the obtained sample was pressured at 1 MPa for 5 minutes. After dehydration, the mixture was tension-dried at 50 ° C. for 2 hours to produce a composite mat having a size of about 200 cm ² .

When the obtained Zn-based HT composite was observed using an electron microscope (SEM), a large number of Zn-based HT fine particles were precipitated on the fiber surface, and the coverage of the pulp fiber with the fine particles (fine particles among the fiber surface). The area ratio of the portion covered with the particles was 25%, the primary particle size of the fine particles was 200 to 500 nm, and the average primary particle size was 300 nm.

When the Zn-based HT composite was analyzed by the ashing treatment, the weight ratio of the cellulose fibers to the inorganic particles was 49.9: 50.1 (weight ratio of the inorganic particles: 50.1% by weight), and the raw material (pulp. It was almost the same as the theoretical value (50% by weight) calculated from the charging ratio of calcium hydroxide). The above weight ratio was calculated from the ratio of the weight of the remaining ash to the original solid content after heating the complex at 525 ° C. for about 2 hours (JIS P 8251: 2003). However, since the ashing treatment at 525 ° C causes a weight loss due to decarboxylation of hydrotalcite and desorption of interlayer water (about 30%), the ash content is calculated based on the weight loss from the measured weight after the ashing treatment. Calculated. The Zn ratio was calculated based on the composition of hydrotalcite.

(3) Manufacture of wet non-woven fabric Coniferous bleached kraft pulp (NBKP) beaten to a Canadian standard drainage degree of 650 ml, Zn-based HT composite that has been disintegrated, polyethylene terephthalate fiber (PET, fiber diameter: 1.7 decitex, fiber). Length: 5 mm) and binder fiber (fiber diameter: 1.7 decitex, fiber length: 5 mm) were mixed in the formulations shown in Table 1 to prepare a raw material for a wet nonwoven fabric. As the binder fiber (heat fusion fiber), a core-sheath type polyester composite fiber (melting point of the sheath portion: 100 to 160 ° C., core portion: polyethylene terephthalate) was used to form a wet nonwoven fabric by a thermal bond method. .. In order to improve the wet strength, 0.3% by weight of the polyamide epoxy-based wet paper strength agent was added in each formulation, the raw materials were dispersed in water, and the basis weight was 15 g using a circular net Yankee dryer paper machine. A non-woven fabric at / m ² was produced by a wet method.

(4) Physical characteristics of the wet nonwoven fabric The physical properties of the obtained wet nonwoven fabric were evaluated based on the following procedure.
Basis weight: Evaluated based on JIS P 8124: 1998.
-Thickness: Evaluated based on JIS P 8118: 1998.
-Density: Calculated from the measured values of thickness and basis weight.
-Tensile strength, elongation: evaluated based on JIS P 8113: 2006.
Wet tensile strength: Evaluated based on JIS P 8135: 1998.
-Air permeability resistance: 32 test samples (50 mm x 50 mm) are stacked and set in the Garley air permeability tester, the inner cylinder of the Garley air permeability tester is gently lowered, and 100 ml of air is used to prepare the test sample. The passing time (seconds) was measured.

As is clear from the table, the wet nonwoven fabric containing the Zn-based HT complex of the present invention had a high ash content but a small decrease in strength.
Experiment 2: Evaluation of wet non-woven fabric
(1) Evaluation of deodorant characteristics The deodorant characteristics of the wet non-woven fabric produced in Experiment 1 were evaluated. All the sheets used for the deodorization test were 1 g.

The deodorization test is conducted based on the method of the SEK mark textile product certification standard (JEC301, Textile Evaluation Technology Council), and evaluates the deodorizing characteristics for ammonia, acetic acid, isovaleric acid, hydrogen sulfide, methyl mercaptan, and indole. did. Ammonia, acetic acid, hydrogen sulfide and methyl mercaptan were quantified using a detector tube, and isovaleric acid and indole were quantified using gas chromatography.

After adjusting the humidity of the sample at 20 ° C. and 65% RH for 24 hours or more, the deodorizing characteristics (decrease rate,%) of the odorous component were evaluated. Here, the reduction rate (%) can be obtained by the following formula from the initial concentration of the odor component and the concentration at the time of measurement.
Decrease rate (%) = (concentration in blank test-concentration at measurement / concentration in blank test) x 100
(2) Evaluation of antibacterial properties The antibacterial properties of the wet non-woven fabric produced in Experiment 1 were evaluated. The antibacterial property test was carried out by the bacterial solution absorption method (quantitative test method in which the test inoculated bacterial solution is directly inoculated onto the test piece) specified in JIS L 1902. Two types of test strains, Staphylococcus aureus NBRC 12732 and Escherichia coil NBRC 3301, were used, and the viable cell count after 18-hour culture was measured by the plyed flat plate culture method. A standard cotton cloth was used as a standard. The test procedure is shown below.
1. 1. Place 0.4 g of the test piece in a vial, add 0.2 ml of the test bacterial solution (containing 0.05% surfactant (Tween80)), and then cover the vial.
2. 2. Incubate the vial at 37 ° C. for 18 hours.
3. 3. 20 ml of the wash-out solution is added to wash out the test bacteria from the test piece, and the viable cell count in the wash-out solution is measured by a pour-brush plate culture method or a luminescence measurement method.
4. The antibacterial activity value is calculated according to the following formula. An antibacterial activity value of 2.0 or more means that the eradication rate of bacteria is 99% or more.

Antibacterial activity value = {log (control sample / viable cell count immediately after incubation)-log (control sample / viable cell count immediately after inoculation)}-{log (test sample / viable cell count immediately after inoculation)-log (test sample / viable cell count immediately after inoculation)-log (test sample / viable cell count immediately after inoculation) number)}
(3) Evaluation of antiviral properties The wet non-woven fabric produced in Experiment 1 was evaluated for its antiviral properties. The antiviral test was carried out based on the JIS method (L 1922: 2016, antiviral test method for textile products). The complex mat used for the test weighed 0.4 g, and a standard cotton cloth was used as the control sample. Feline calicivirus (Strain: F-9 ATCC VR-782) was used as the test virus species. The test procedure is shown below.
1. 1. Put 0.4 g of the test piece in a vial, drop 0.2 ml of the test virus solution, and then cover the vial.
2. 2. The vial is allowed to stand at 25 ° C. for 2 hours.
3. 3. The virus is washed out from the test piece by adding 20 ml of the wash-out solution, and the infectious titer is calculated by the plaque measurement method.
4. The antiviral activity value (Mv) is calculated by the following formula. In addition, JIS stipulates that the antiviral effect is effective when Mv ≧ 2.0 and sufficiently effective when Mv ≧ 3.0.
Antiviral activity value (Mv) = Log (Vb) -Log (Vc)
Mv: Antiviral activity value Log (Vb): Infectious logarithm after 2 hours of action of the control sample (average value of 3 samples)
Log (Vc): Common logarithm of infectious value after 2 hours of action of antiviral sample (average value of 3 samples)
(4) Evaluation Results The evaluation results are shown in the table below. The wet nonwoven fabrics (Samples 1 to 3) according to the present invention showed high deodorizing ability with respect to odorous components. In addition, the wet nonwoven fabric according to the present invention exhibited excellent antibacterial and antiviral properties.

Claims (15)

A wet nonwoven fabric comprising (a) a composite of inorganic particles and fibers, (b) synthetic fibers, and (c) a fibrous binder.
The content of (a) is 60% by weight or less based on the total weight of the wet nonwoven fabric, and 15% or more of the fiber surface in the composite of (a) is covered with inorganic particles, and the synthetic fiber of (b) is covered. Is different from the fibrous binder of (c), and the above-mentioned wet non-woven fabric is formed by solidifying the fibrous binder melted by the heat of the manufacturing process to form a non-woven fabric. The wet non-woven fabric according to claim 1 , wherein the fibrous binder contains heat-sealed fibers. The wet non-woven fabric according to claim 1 or 2 , wherein the non-woven fabric is a thermal bonded non-woven fabric. The wet nonwoven fabric according to any one of claims 1 to 3 , wherein the content of (a) is 10% by weight or more and 40 % by weight or less with respect to the total weight of the wet nonwoven fabric. The wet non-woven fabric according to any one of claims 1 to 4 , wherein the average primary particle diameter of the inorganic particles is 1 μm or less. The wet non-woven fabric according to any one of claims 1 to 5 , wherein the weight ratio of the fiber to the inorganic particles in the complex is 5/95 to 95/5. The wet non-woven fabric according to any one of claims 1 to 6 , wherein the fibers constituting the complex are cellulose fibers. The wet non-woven fabric according to any one of claims 1 to 7 , wherein the cellulose fiber is a pulp derived from wood. The wet non-woven fabric according to any one of claims 1 to 8 , wherein the inorganic particles are hydrotalcite. The wet non-woven fabric according to claim 9 , wherein the hydrotalcite has magnesium or zinc as a divalent metal ion. The wet non-woven fabric according to claim 9 or 10 , wherein the hydrotalcite has aluminum as a trivalent metal ion. The wet non-woven fabric according to any one of claims 1 to 11 for use in hygiene products. The wet non-woven fabric according to any one of claims 1 to 12 , which is used for a mask or a wiper. The wet non-woven fabric according to any one of claims 1 to 13 , which is used for deodorizing, antibacterial or antiviral purposes. The method for producing a wet nonwoven fabric according to any one of claims 1 to 14 .
The above method comprising a step of forming a nonwoven fabric by a wet method from a raw material containing (a) a composite of inorganic particles and fibers, (b) synthetic fibers, and (c) a fibrous binder.

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