JP2019137962A - Dry-type nonwoven fabric - Google Patents

Abstract

To provide a method for producing a dry-type nonwoven fabric from a composite of inorganic particles and fiber.SOLUTION: A dry-type nonwoven fabric comprising a composite of inorganic particles and fiber is provided. In the dry-type nonwoven fabric, 15% or more of the fiber surface of the composite is coated with inorganic particles.SELECTED DRAWING: None

Description

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

  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 used in diapers, sanitary products, wipers, masks and other sanitary products, gas or liquid filtration filters, roofing materials (roofing materials), building materials and civil engineering applications, 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 trapping properties required for filters in general, the above deodorizing function, and especially the growth and development of mold and mycelia 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.

In general, hydrotalcite is represented by the general formula [M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] [A ⁿ⁻ _{x / n} · mH 2 O] (wherein M ²⁺ represents a divalent metal ion, and M ³⁺ represents A compound represented by a trivalent metal ion, wherein A ⁿ⁻ _{x / n} represents an interlayer anion, and 0 <x <1, n is a valence of A, and 0 ≦ m <1. It is a substance utilized as a catalyst, a pharmaceutical, an additive for resin, etc. (patent documents 6-8, nonpatent literature 1-3).

  Similar to talc and smectite, hydrotalcite is a metal hydroxide having a layered crystal structure, and each crystal piece of hydrotalcite is often leaf-like or scaly. Hydrotalcite includes manasseite, a polytype of hydrotalcite, pyroaurite and sjgrenite, whose metal contained in the hydroxide sheet is magnesium and iron, and divalent and trivalent. A green rust having a hydroxide sheet of iron is known. Since the main skeleton is double hydroxide, it is also called layered double hydroxide (LDH). Hydrotalcite is naturally produced but its production 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. In Non-Patent Document 4, it is proposed to remove phosphorus from waste water using hydrotalcite-supporting fibers.

JP-A-10-120923 JP 11-315492 A JP 2008-031591 A Japanese Patent Laid-Open No. 11-107033 International Publication No. 2014/097929 JP2015-193000A JP 2013-085568 A JP 2009-143798 A JP 2012-144829 A

“Application of hydrotalcite to water environment conservation and purification”, The Chemical Times, no. 1, 2005 "Synthesis and anion exchange characteristics of Fe-Mg and Al-Mg hydrotalcite-like compounds", J. Ion Exchange, vol. 16, no. 1, 2005 "Surfactant adsorption property of layered double hydroxide and structural stability of emulsified gel", Toyo University Bulletin, Natural Sciences, 56, 43-52, 2012 “Phosphorus removal performance of hydrotalcite-supporting fiber (HTCF) from actual wastewater”, Journal of Japan Society on Water Environment, vol. 30, no. 11, pp 671-676, 2007

  The subject of this invention is providing the technique which manufactures the nonwoven fabric excellent from the composite of inorganic particles, such as a hydrotalcite, and a fiber with a dry process.

  As a result of intensive studies on the above problems, the present inventor obtained a high-quality dry nonwoven fabric excellent in strength and the like by using a composite (composite fiber) in which 15% or more of the fiber surface is coated with inorganic particles. As a result, the present invention has been completed.

That is, the present invention includes, but is not limited to, the following inventions.
(1) A dry nonwoven fabric comprising a composite of inorganic particles and fibers, wherein 15% or more of the fiber surface of the composite is coated with inorganic particles.
(2) The nonwoven fabric according to (1), comprising a composite of inorganic particles and fibers and a binder.
(3) The nonwoven fabric according to (1) or (2), comprising a composite of inorganic particles and fibers and a synthetic fiber.
(4) The nonwoven fabric in any one of (1)-(3) whose average primary particle diameter of an inorganic particle is 1 micrometer or less.
(5) The nonwoven fabric in any one of (1)-(4) whose weight ratio of the fiber and inorganic particle in a composite_body | complex is 5 / 95-95 / 5.
(6) The nonwoven fabric in any one of (1)-(5) whose fiber which comprises a composite_body | complex is a cellulose fiber.
(7) The nonwoven fabric according to any one of (1) to (6), wherein the cellulose fibers are wood-derived pulp.
(8) The nonwoven fabric according to any one of (1) to (7), wherein the inorganic particles are hydrotalcite.
(9) The nonwoven fabric according to (8), wherein the hydrotalcite has magnesium or zinc as a divalent metal ion.
(10) The nonwoven fabric according to (8) or (9), wherein the hydrotalcite has aluminum as a trivalent metal ion.
(11) The nonwoven fabric according to any one of (1) to (10) for use in sanitary goods.
(12) The nonwoven fabric according to any one of (1) to (11) for use in a mask or a wiper.
(13) The nonwoven fabric according to any one of (1) to (12), which is used for deodorization, antibacterial use, or antiviral use.
(14) A method for producing the nonwoven fabric according to any one of (1) to (13), which comprises a step of forming a nonwoven fabric in a dry process from a raw material containing a composite of inorganic particles and fibers.

  According to the present invention, an excellent dry nonwoven fabric can be obtained from a composite of inorganic particles and fibers. A dry nonwoven fabric having various properties can be obtained by appropriately selecting the type of inorganic particles. For example, a dry nonwoven fabric obtained from a composite of hydrotalcite and fibers has an excellent deodorizing effect and the like. It can be suitably used for articles and the like.

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

  The composite used in the present invention is not simply a mixture of fibers and inorganic particles, but the fibers and inorganic particles are bound together by hydrogen bonding or the like, so that the inorganic particles are not easily dropped even by disaggregation treatment. Is.

Dry nonwoven fabric The dry nonwoven fabric of the present invention is produced from a raw material containing a composite fiber by a dry method. In the production of a dry nonwoven fabric, synthetic fibers, paper strength agents, binders, fillers (fillers), and the like may be further added as necessary. Examples of the dry method include a card method (carding method), an air array method, and a web bonding method for forming a web, and a chemical bond method, a thermal bond method, a spunlace method, a needle punch method, and the like.

  In the card method, a composite and thermoplastic synthetic fiber are charged into a card machine to form a fiber accumulation layer (nonwoven web), which is heat-treated at a temperature equal to or higher than the melting temperature of the thermoplastic fiber. It can be produced by a thermal bond method in which a part of the synthetic fiber is melted to bond the fibers together, or a method in which the nonwoven web is hydroentangled and then subjected to heat treatment. In addition, examples of the web production method by the card method include parallel web, cross web, random web, Chris cross web, semi-random web, and the like.

  The air array method is a drying heating process (drying) in which a fibrillated raw material fiber is transported in an air stream to form a web, a binder is applied to the web, and the fibers of the fiber web are bonded together by a binder. Process). Examples of the air array method include the Honshu Paper Manufacturing Method (Kinocross Method), the Karl Croyer Method, the Scan Web Method (Danweb Method), the J & J Method, the KC Method, and the Scott Paper Method.

  In addition, when manufacturing the dry-type nonwoven fabric of this invention by the air array method, in order to adhere fibers, you may use a binder. The binder to be used can be appropriately selected according to need. For example, casein, sodium alginate, hydroxyethyl cellulose, carboxymethyl cellulose sodium salt, polyvinyl alcohol (PVA), polyacrylic acid soda and other aqueous binders, polyacrylic Acid esters, acrylic / styrene copolymers, polyvinyl acetate, ethylene / vinyl acetate copolymers, acrylonitrile / butadiene copolymers, methyl methacrylate / butadiene copolymer emulsions, styrene / butadiene copolymer latex An emulsion type binder such as can be used.

  Further, the dry nonwoven fabric according to one embodiment of the present invention may be provided with surface irregularities on one or both sides of a sheet formed by the above-described method, and can be subjected to treatment such as embossing, for example. . This facilitates impregnation of the liquid. Furthermore, since the specific surface area is increased due to the unevenness, the contact area to the target portion is increased, and therefore various functions such as deodorization and antibacterial can be more easily expressed.

  When manufacturing a dry-type nonwoven fabric using a composite, you may provide various organic substances, such as a polymer, various inorganic substances, such as a pigment, and various fibers, such as a pulp fiber. Moreover, you may give various fibers, such as various organic substances, such as a polymer, various inorganic substances, such as a pigment, and a pulp fiber, to a nonwoven fabric later.

  As the various fibers, for example, cellulosic fibers can be used preferably. Coniferous bleached kraft pulp (NBKP), unbleached kraft pulp (NUKP), hardwood bleached kraft pulp (LBKP), hardwood unbleached kraft Chemical pulps such as pulp (LUKP), softwood bleached sulfite pulp (NBSP) or unbleached sulfite pulp (NUSP), hardwood bleached sulfite pulp (LBSP), hardwood unbleached sulfite pulp (LUSP), or , Ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP, etc.) and other mechanical pulp, deinked pulp (DIP), non-wood fiber pulp such as cotton and kenaf, and recycled fiber such as rayon Can be mentioned. Only one type of these fibers can be blended, or two or more types can be blended in combination.

  In order to impart opacity, incombustibility and flame retardancy to the dry nonwoven fabric, the filler may be contained in a range of, for example, 30% by mass or less with respect to the total mass of the dry nonwoven fabric. As a filler in that case, it is preferable to use a calcined clay from the viewpoints of opacity, incombustibility 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 composite, magnesium carbonate, barium carbonate, Mention may be made of inorganic fillers such as titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide. Depending on the purpose of the wallpaper, these fillers may not be included.

  In the dry nonwoven fabric, a sizing agent can be used in the same manner as ordinary paper. In that case, the sizing agent may be internally added or externally added. Examples of the sizing agent to be used include rosin sizing agents, rosin binder resin sizing agents, alpha carboxymethyl saturated fatty acids, alkyl ketene dimers, alkenyl succinic anhydrides, cationic polymer sizing agents, and the like. In addition, various modified starches such as oxidized starch and enzyme-modified starch, water-soluble binders such as carboxymethylcellulose and casein, surface paper strength agents, dyes, pigments (clay, kaolin, calcium carbonate, titanium dioxide, etc.) are used as appropriate. can do.

The basis weight of the dry nonwoven fabric according to one embodiment of the present invention may be appropriately selected according to the use and the like. For example, from the viewpoint of the strength of the sheet, the basis weight is preferably 5 g / m ² or more, and 10 g / m. ² or more is more preferable, and may be 12 g / m ² or more. Further, from the viewpoints of handleability and transportation cost, 120 g / m ² or less is more preferable, 100 g / m ² or less is more preferable, and 80 g / m ² or less or 60 g / m ² or less may be used. When the dry 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 the minimum strength in handling during production. The basis weight (weight per unit area) of the nonwoven fabric in the present invention is that the nonwoven fabric having an area of 0.05 m ² or more is dried at 105 ° C. until a certain mass is reached, and then left in a temperature-controlled room at 20 ° C. and 65% RH for 16 hours or more. The mass should be measured. Moreover, the thickness of a dry-type nonwoven fabric can be 20-5000 micrometers, It is preferable that it is the range of 30-250 micrometers, It is good also as 35-200 micrometers, 40-150 micrometers, and also 45-100 micrometers. When the dry 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 dry nonwoven fabric is not particularly limited.

Further, in order to effectively express the various performances, it is preferred that the specific surface area is ^{3m 2} / ^g~200m 2 / g, more ^{10m 2} / ^g~180m 2 / g is more preferable. From the same viewpoint, the ash content in the sheet is preferably 3% by weight to 80% by weight, and more preferably 10% by weight or more.

  The ash content of the dry nonwoven fabric can be adjusted by the amount of inorganic particles contained in the composite and the amount of filler (hereinafter also referred to as internal filler) added as appropriate separately from the inorganic particles combined with the composite. 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 dry nonwoven fabric is preferably 10% by weight or more and 90% by weight or less, more preferably 20% by weight or more and 80% by weight or less with respect to the total weight of the dry nonwoven fabric. Is more preferable, and may be 60% by weight or less or 40% by weight or less. When the content of the composite contained in the dry nonwoven fabric is within the above range, the effects of the present invention can be sufficiently exerted.

  The dry nonwoven fabric of the present invention can be used in various applications, such as paper, fiber, cellulosic composite material, filter material, paint, plastic and other resins, rubber, elastomer, ceramic, glass, tire, building material ( Asphalt, asbestos, cement, board, concrete, brick, tile, plywood, fiberboard, etc.), various carriers (catalyst carrier, pharmaceutical carrier, agricultural chemical carrier, microbial carrier, etc.), adsorbent (impurity removal, deodorization, dehumidification, etc.) , Anti-wrinkle agent, 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 Materials, paste materials, food additives, tablet excipients, dispersants, shape retention agents, water retention agents, filter aids, essential oil materials, oil treatment agents, oil modifiers, radio wave absorbers, insulation materials, sound insulation materials, Prevention Materials, semiconductor sealing materials, radiation shielding materials, cosmetics, fertilizers, feeds, fragrances, additives for paints, adhesives and resins, anti-discoloring agents, conductive materials, heat transfer materials, sanitary products (disposable diapers, sanitary napkins, It can be widely used for all purposes such as incontinence pads and breast milk pads. Suitable uses of the nonwoven fabric according to the present invention include sanitary products such as diapers, sanitary products, wipers, masks, filters for gas or liquid filtration, building materials and civil engineering applications such as roofing materials (roofing materials), automobile interior materials, For example, clothing.

Composite of inorganic particles and fiber (composite fiber)
In the present invention, the inorganic particles to be combined with the fiber are not particularly limited, but are preferably inorganic particles that are insoluble or hardly soluble in water. Inorganic particles may be synthesized in an aqueous system, and the composite may be used in an aqueous system. Therefore, the inorganic particles are preferably insoluble or hardly soluble in water.

The inorganic particle said here means a metal or a metal compound. The metal compound is a metal cation (for example, Na ⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Ba ²⁺ ) and an anion (for example, 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.), which are generally called inorganic salts Say. The synthesis method of these inorganic particles may be either a gas-liquid method or a liquid-liquid method. An example of the gas-liquid method is a carbon dioxide gas method. For example, magnesium carbonate can be synthesized by reacting magnesium hydroxide and carbon dioxide gas. Examples of liquid-liquid methods include reacting acid (hydrochloric acid, sulfuric acid, etc.) and base (sodium hydroxide, potassium hydroxide, etc.) by neutralization, reacting inorganic salt with acid or base, The method of making it react is mentioned. For example, barium sulfate and sulfuric acid are reacted to obtain barium sulfate, aluminum sulfate and sodium hydroxide are reacted to obtain aluminum hydroxide, or calcium carbonate and aluminum sulfate are reacted to produce calcium and aluminum. Composite inorganic particles can be obtained. In addition, when synthesizing inorganic particles in this manner, any metal or metal compound can be allowed to coexist in the reaction solution. In this case, these metals or metal compounds are efficiently incorporated into the inorganic particles and are combined. Can be For example, when phosphoric acid is added to calcium carbonate to synthesize calcium phosphate, composite particles of calcium phosphate and titanium can be obtained by allowing titanium dioxide to coexist in the reaction solution.

  In one preferred embodiment, the composite of the present invention can be obtained by synthesizing inorganic particles in the presence of fibers. This is because the fiber surface is a suitable place for the precipitation of inorganic particles, and it is easy to synthesize a composite of inorganic particles and fibers.

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

  In addition, 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 according to the application can be generated by an aging process, or by pulverization. Agglomerates can also be made fine. For grinding, ball mill, sand grinder mill, impact mill, high-pressure homogenizer, low-pressure homogenizer, dyno mill, ultrasonic mill, kanda grinder, attritor, stone mill, vibration mill, cutter mill, jet mill, breaker, beater Short shaft extruder, twin screw extruder, ultrasonic stirrer, household juicer mixer and the like.

  The binding strength between fibers and inorganic particles in the composite can be evaluated by, for example, a numerical value such as ash yield (%), that is, (ash content of sheet / ash content of composite before disaggregation) × 100. Specifically, the composite is dispersed in water, adjusted to a solid content concentration of 0.2%, and disaggregated for 5 minutes with a standard disintegrator specified in JIS P 8220-1: 2012, and then in accordance with 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 content yield of the composite used in the present invention is 20% by mass or more, and more preferably 50% by mass or more.

(Hydrotalcite and fiber composite)
As an example of the composite used in the dry nonwoven fabric of the present invention, a composite of hydrotalcite (HT) and fibers will be described below. This composite has high deodorizing properties.

In general, hydrotalcite is [M2 ⁺ _1- xM3 ⁺ _x (OH) ₂ ] [An ^- _{x /} n.mH2O] (wherein M2 ⁺ is a divalent metal ion and M3 ⁺ is trivalent. A ⁿ⁻ _{x / n} represents an interlayer anion, and 0 <x <1, where n is the valence of A, and 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+. there ^{M 3+} are, for ^{example, Al 3+, Fe 3+, Cr} 3+, Ga 3+ , etc., which ^{a n-} is an interlayer anion, for _{^{example, OH -, Cl -, CO}} 3 -, SO 4 - n-valent such as Anions can be mentioned, and x is generally in the range of 0.2 to 0.33. Of these, Mg ²⁺ , Zn ²⁺ , Fe ²⁺ , and Mn ²⁺ are preferable as the divalent metal ion. The crystal structure has a laminated structure composed of a two-dimensional basic layer in which octahedral brucite units having a positive charge are arranged and an intermediate layer having a negative charge.

  Hydrotalcite has been used for various applications utilizing its anion exchange function, such as ion exchange materials, adsorbents, deodorants and the like. In addition, by utilizing the combination of constituent metal ions, hydrotalcite in which each constituent metal ion is in a well-mixed state is heated and dehydrated, or further heated and fired to easily produce a complex oxide with a uniform composition. In some cases, it can be obtained for use as a catalyst.

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

  Although the present invention relates to a composite of hydrotalcite and fibers, 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 by hydrotalcite, more preferably 40% or more, but according to the present invention, the coverage is 60% or more. It is also possible to produce a composite of 80% or more. In a preferred embodiment, the composite of hydrotalcite and fiber according to the present invention is not only fixed on the outer surface of the fiber and the inner side of the lumen, but also generated on the inner side of the microfibril. It is clear from the result of microscopic observation.

  When hydrotalcite and fiber are composited according to the present invention, hydrotalcite is not only easily mixed with the fiber compared with the case where hydrotalcite is mixed with fiber, but also uniformly dispersed without agglomeration. Product can be obtained. That is, according to the present invention, the yield of the composite of hydrotalcite and fibers to the product (weight ratio in which the added hydrotalcite remains in the product) can be 65% or more, and 70% or more. Or 85% or more.

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

  The synthesis method of hydrotalcite can be based on a known method. For example, the fibers are immersed in an aqueous carbonate solution containing carbonate ions constituting the intermediate layer and an alkaline solution (such as sodium hydroxide) in the reaction vessel, and then an acid solution (divalent metal ions and trivalent ions constituting the basic layer). Hydrotalcite is synthesized by adding a metal salt aqueous solution containing metal ions and controlling the temperature, pH, etc., and coprecipitation reaction. Further, in the reaction vessel, the fiber is immersed in an acid solution (metal salt aqueous solution containing divalent metal ions and trivalent metal ions constituting the basic layer), and then carbonate aqueous solution containing carbonate ions constituting the intermediate layer. Hydrotalcite can also be synthesized by dropwise addition of an alkaline solution (such as sodium hydroxide) and controlling the temperature, pH, etc. and coprecipitation reaction. Although the reaction at normal pressure is common, there is another method obtained by hydrothermal reaction using an autoclave or the like (Japanese Patent Laid-Open No. 60-6619).

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

  In the present invention, water is used for the preparation of the suspension. As this water, normal tap water, industrial water, ground water, well water, etc. can be used, ion-exchanged water, distilled water, Pure water, industrial waste water, and water obtained during the production process can be suitably used.

  In the present invention, carbonate ions, nitrate ions, chloride ions, sulfate ions, phosphate ions and the like can be used as anions as interlayer anions. When carbonate ions are used as interlayer anions, sodium carbonate is used as the 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 of a paper mill can be suitably used as the carbon dioxide-containing gas. In addition, a carbonation reaction can also be performed using carbon dioxide generated from the lime baking step.

  When producing the composite of the present invention, various known auxiliaries can be further added. For example, chelating agents can be added to the neutralization reaction, specifically, polyhydroxycarboxylic acids such as citric acid, malic acid and tartaric acid, dicarboxylic acids such as oxalic acid, sugar acids such as gluconic acid, Aminopolycarboxylic acids such as acetic acid and ethylenediaminetetraacetic acid and their alkali metal salts, alkali metal salts of polyphosphoric acid such as hexametaphosphoric acid and tripolyphosphoric acid, amino acids such as glutamic acid and aspartic acid and their alkali metal salts, acetylacetone, acetoacetic acid Examples thereof include ketones such as methyl and allyl acetoacetate, saccharides such as sucrose, and polyols such as sorbitol. In addition, as surface treatment agents, saturated fatty acids such as palmitic acid and stearic acid, unsaturated fatty acids such as oleic acid and linoleic acid, resin acids such as alicyclic carboxylic acid and abietic acid, salts, esters and ethers thereof, alcohols Activators, sorbitan fatty acid esters, amide or amine surfactants, polyoxyalkylene alkyl ethers, polyoxyethylene nonyl phenyl ether, sodium alpha olefin sulfonate, long chain alkyl amino acids, amine oxides, alkyl amines, fourth A quaternary ammonium salt, aminocarboxylic acid, phosphonic acid, polyvalent carboxylic acid, condensed phosphoric acid and the like can be added. Moreover, a dispersing agent can also be used as needed. Examples of the dispersant include sodium polyacrylate, sucrose fatty acid ester, glycerin fatty acid ester, acrylic acid-maleic acid copolymer ammonium salt, methacrylic acid-naphthoxypolyethylene glycol acrylate copolymer, methacrylic acid-polyethylene glycol. Examples include monomethacrylate copolymer ammonium salts and polyethylene glycol monoacrylate. These can be used alone or in combination. The timing of addition may be before or after the neutralization reaction. Such additives can be added to the hydrotalcite in an amount of preferably 0.001 to 20%, more preferably 0.1 to 10%.

(Reaction conditions)
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.

  In the present invention, the neutralization reaction can be a batch reaction or a continuous reaction. In general, it is preferable to perform 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 performed on a scale of 100 L or less, or may be performed on a scale of more than 100 L. The size of the reaction vessel can be, for example, about 10 L to 100 L, or about 100 L to 1000 L.

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

  Furthermore, the synthesis reaction can be controlled by the reaction time. Specifically, the synthesis reaction can be controlled by adjusting the time that the reactants stay in the reaction tank. In addition, in this invention, reaction can also be controlled by stirring the reaction liquid of a reaction tank, or making neutralization reaction multistage reaction.

  In the present invention, since the complex which is a reaction product is obtained as a suspension, it is stored in a storage tank or subjected to processing such as concentration, dehydration, pulverization, classification, aging, and dispersion as necessary. Can do. These can be performed by known processes, and may be appropriately determined in consideration of the application and energy efficiency. For example, the concentration / dehydration treatment is performed using a centrifugal dehydrator, a sedimentation concentrator, or the like. Examples of the centrifugal dehydrator include a decanter and a screw decanter. When using a filter or a dehydrator, the type is not particularly limited and a general one can be used. For example, a pressure-type dehydrator such as a filter press, a drum filter, a belt press, a tube press, A calcium carbonate cake can be obtained by suitably using a vacuum drum dehydrator such as an Oliver filter. For grinding, ball mill, sand grinder mill, impact mill, high-pressure homogenizer, low-pressure homogenizer, dyno mill, ultrasonic mill, kanda grinder, attritor, stone mill, vibration mill, cutter mill, jet mill, breaker, beater Short shaft 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 round hole screen, a vibrating screen, a heavy foreign matter cleaner, a lightweight foreign matter cleaner, a reverse cleaner, a sieving tester, and the like. Examples of the dispersion method include a high-speed disperser and a low-speed kneader.

  The composite obtained by the present invention can be blended in a filler or pigment in a suspension state without being completely dehydrated, but can also be dried to form a powder. Although there is no restriction | limiting in particular also about the dryer in this case, For example, an airflow dryer, a band dryer, a spray dryer etc. can be used conveniently.

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

  Further, the composite obtained by the present invention can be modified by a known method. For example, in an embodiment, the surface can be hydrophobized to improve miscibility with a resin or the like.

(Fiber constituting the composite)
In the present invention, hydrotalcite and fiber are combined. The fibers constituting the composite are not particularly limited. For example, natural fibers such as cellulose, synthetic fibers that are artificially synthesized from raw materials such as petroleum, and regenerated fibers such as rayon and lyocell (semi-synthetic fibers) In addition, inorganic fibers including ceramics can be used without limitation. In addition to the above, the natural fibers include protein fibers such as wool, silk thread and collagen fibers, and complex sugar chain fibers such as chitin / chitosan fibers and alginic acid fibers.

  Examples of cellulosic materials include pulp fibers (wood pulp and non-wood pulp) and bacterial cellulose. Wood pulp may be produced by pulping wood materials. Wood materials include red pine, black pine, todomatsu, spruce, beech pine, larch, fir, tsuga, cedar, hinoki, larch, syrup, spruce, hiba, douglas fir, hemlock, white fur, spruce, balsam fur, cedar, pine, Coniferous trees such as Merck pine, Radiata pine, etc., and mixed materials thereof, beech, hippopotamus, alder tree, oak, tab, shii, birch, broadleaf tree, poplar, tamo, dragonfly, eucalyptus, mangrove, lawan, acacia, etc. Examples are materials.

  The method for pulping the 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 pulping method, for example, chemical pulp digested by kraft method, sulfite method, soda method, polysulfide method, etc .; mechanical pulp obtained by pulping by mechanical force such as refiner, grinder; Semi-chemical pulp obtained by carrying out pulping by mechanical force after pretreatment by; waste paper pulp; deinked pulp and the like. Wood pulp may be unbleached (before bleaching) or bleached (after bleaching). It may be beaten or not beaten.

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

  The pulp fiber may be either unbeaten or beaten, and may be selected according to the physical properties of the composite sheet, but it is preferable to beaten. Thereby, improvement of sheet strength and promotion of calcium carbonate fixation can be expected. On the other hand, unbeaten pulp improves the yield when making a composite sheet when a composite sheet containing the composite is once prepared and used as a raw material for the nonwoven fabric, or the composite sheet is crushed. When making a non-woven fabric, the sheet strength becomes weak, so that it is easy to break and is preferable.

  Synthetic fibers include polyester, polyamide, polyolefin, acrylic, nylon, acrylic, vinylon, and ceramic fibers. Semi-finished fibers include rayon and acetate. Inorganic fibers include glass fibers, carbon fibers, and various metal fibers. Is mentioned.

Further, these cellulose raw materials are further processed to give powdery cellulose, chemically modified cellulose such as oxidized cellulose, and cellulose nanofiber: CNF (microfibrillated cellulose: MFC, TEMPO oxidized CNF, phosphate esterified CNF, carboxymethylated). CNF, machine pulverized CNF, etc.) can also be used. As the powdered cellulose used in the present invention, for example, a fixed particle size in the form of a rod shaft produced by a method of purifying and drying an undegraded residue obtained after acid hydrolysis of a 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 Industries), Theolas (manufactured by Asahi Kasei Chemicals), and Avicel (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 X-ray diffraction is preferably 70 to 90%, and the volume average particle size by a laser diffraction type particle size distribution analyzer. Is preferably 1 μm or more and 100 μm or less. The oxidized cellulose used in the present invention can be obtained, for example, by oxidizing in water using an oxidizing agent in the presence of a compound selected from the group consisting of N-oxyl compounds and bromides, iodides or mixtures thereof. it can. As the cellulose nanofiber, a method of defibrating the cellulose raw material is used. As the defibrating 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 single or multi-screw kneader, a bead mill, or the like. A method of defibration can be used. Cellulose nanofibers may be produced by combining one or more of the above methods. The fiber diameter of the produced cellulose nanofiber can be confirmed by observation with an electron microscope, and is, for example, in the range of 5 nm to 1000 nm, preferably 5 nm to 500 nm, more preferably 5 nm to 300 nm. When producing the cellulose nanofiber, before and / or after the cellulose is defibrated and / or refined, an arbitrary compound may be further added and reacted with the cellulose nanofiber to modify the hydroxyl group. it can. As functional groups to be modified, acetyl group, ester group, ether group, ketone group, formyl group, benzoyl group, acetal, hemiacetal, oxime, isonitrile, allene, thiol group, urea group, cyano group, nitro group, azo group , Aryl group, aralkyl group, amino group, amide group, imide group, acryloyl group, methacryloyl group, propionyl group, propioyl group, butyryl group, 2-butyryl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group , Decanoyl group, undecanoyl group, dodecanoyl group, myristoyl group, palmitoyl group, stearoyl group, pivaloyl group, benzoyl group, naphthoyl group, nicotinoyl group, isonicotinoyl group, furoyl group, cinnamoyl group, etc., 2-methacryloyl group Isocyanate groups such as oxyethylisocyanoyl 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 group, undecyl group, dodecyl group, myristyl group, palmityl group, stearyl group and other alkyl groups, oxirane group, oxetane group, oxyl group, thiirane group, thietane group and the like. 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 be an unsaturated bond. The compound used for introducing these functional groups is not particularly limited. For example, a compound having a phosphoric acid-derived group, a compound having a carboxylic acid-derived group, a compound having a sulfuric acid-derived group, or a sulfonic acid-derived compound And the like, compounds having an alkyl group, compounds having an amine-derived group, and the like. Although it does not specifically limit as a compound which has a phosphoric acid group, Lithium dihydrogen phosphate which is phosphoric acid and the lithium salt of phosphoric acid, Dilithium hydrogen phosphate, Trilithium phosphate, Lithium pyrophosphate, Lithium polyphosphate is mentioned. . Furthermore, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate and sodium polyphosphate which are sodium salts of phosphoric acid are mentioned. Furthermore, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate which are potassium salts of phosphoric acid are mentioned. Further, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate which are ammonium salts of phosphoric acid are included. Of these, phosphoric acid, sodium phosphate, phosphoric acid potassium salt, and phosphoric acid ammonium salt are preferred from the viewpoint of high efficiency in introducing a phosphate group and easy industrial application. Sodium dihydrogen phosphate Although disodium hydrogen phosphate is more preferable, it 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, but examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. It is done. Although it does not specifically limit as a derivative of the compound which has a carboxyl group, The derivative of the acid anhydride of the compound which has a carboxyl group and the acid anhydride imidation of a compound which has a carboxyl group are mentioned. Although it does not specifically limit as an acid anhydride imidation thing of a compound which has a carboxyl group, Imidation thing of dicarboxylic acid compounds, such as maleimide, succinic acid imide, and phthalic acid imide, is mentioned. The acid anhydride derivative of the compound having a carboxyl group is not particularly limited. For example, at least some of the hydrogen atoms of the acid anhydride of the compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc. are substituted (for example, alkyl group, phenyl group, etc. ) Are substituted. Among the compounds having a group derived from a carboxylic acid, maleic anhydride, succinic anhydride, and phthalic anhydride are preferred because they are easily applied industrially and easily gasified, but are not particularly limited. Further, the cellulose nanofiber may be modified in such a manner that the compound to be modified is physically adsorbed on the cellulose nanofiber without being chemically bonded. Examples of the physically adsorbing compound include surfactants, and any of anionic, cationic, and nonionic may be used. When the above-described modification is performed before cellulose is defibrated and / or pulverized, these functional groups can be removed after defibrating and / or pulverization to return to the original hydroxyl group. By performing the modification as described above, it is possible to promote the defibration of the cellulose nanofiber or to easily mix it with various substances when the cellulose nanofiber is used.

  The fibers shown above may be used alone or in combination. Especially, it is preferable that wood pulp is included or the combination of wood pulp, non-wood pulp, and / or synthetic fiber is included, and it is more preferable that it is only wood pulp.

  In a preferred embodiment, the fibers constituting the composite of the present invention are pulp fibers. Further, for example, a fibrous material 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 fibers Examples of the synthetic fibers used in the present invention include polyamide fibers such as polyester, nylon and aramid, polyolefin fibers, polyurethane fibers, acrylic fibers, polyvinyl alcohol fibers, vinylon, vinylidene, and polyvinyl chloride. Examples of the polyolefin fibers include polyethylene fibers and polypropylene fibers. Examples of the polyethylene fibers include high density polyethylene, low density polyethylene, ultra low density polyethylene, linear low density polyethylene, and ultra high molecular weight polyethylene. It is done. Examples of the polyester fiber include polyethylene terephthalate (PET) fiber, polytrimethylene terephthalate (PTT) fiber, and polybutylene terephthalate (PBT) fiber. Examples of polyamide fibers include nylon fibers and aramid fibers. The synthetic fiber used in the present invention is preferably a polyester-based, polypropylene-based, or polyethylene-based synthetic fiber from the viewpoint of mixability with the composite (composite fiber) and papermaking properties (water squeezing, texture). It is. In particular, when considering mixability, it is preferable to use a polyester-based synthetic fiber.

  The synthetic fiber may be a main fiber having a single concentric structure, or may be a core-sheath type fiber having different melting points between the core and the sheath. 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. In addition, 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 considering the high temperature treatment and stability such as embossing at a high temperature in the subsequent stage, 200 More preferably, it is in the range of ˜260 ° C. When the melting point is as low as less than 110 ° C., when a dry nonwoven fabric is produced, dirt (fuzzing) derived from synthetic fibers tends to occur in the dryer. On the other hand, blending a synthetic fiber having a melting point exceeding 300 ° C. is not only technically meaningless but also uneconomical. When the core-sheath type synthetic fiber is used, the one having the melting point of the sheath within the above range is selected. In addition, the measurement of melting | fusing point of a synthetic fiber is based on JISK7121: 2012.

  The content of the composite contained in the dry nonwoven fabric is preferably 10% by weight or more and 90% by weight or less, more preferably 20% by weight or more and 80% by weight or less with respect to the total weight of the dry nonwoven fabric. Is more preferable, and may be 60% by weight or less or 40% by weight or less. When the content of the composite contained in the dry nonwoven fabric is within the above range, the effects of the present invention can be sufficiently exerted.

  In addition, you may use a binder as needed. Examples of the binder include heat-fusible fibers and water-based adhesives. Examples of the heat-fusible fiber include a core-sheath polyester-based composite fiber, a polyethylene terephthalate (PET) fiber, a core-sheath-type polyolefin-based composite fiber, and a hydrophilic pulp-like multibranched fiber. Examples of the core-sheath polyester composite fiber include a composite fiber (core-sheath fiber) in which the sheath (low melting point component) is modified polyester and the core (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 (low melting point component) is made of polyethylene and the core (high melting point component) is made of polypropylene. Moreover, the pulp-like multibranched fiber which has hydrophilic property is also called a polyolefin synthetic pulp, For example, what is marketed by the brand name of SWP from Mitsui Chemicals, Inc. can be mentioned as an example. Water-based adhesives include casein, sodium alginate, hydroxyethylcellulose, sodium carboxymethylcellulose, polyvinyl alcohol (PVA), water-soluble adhesives such as sodium polyacrylate, polyacrylates, acrylic / styrene copolymers, polyacetic acid Emulsion adhesives such as vinyl, ethylene / vinyl acetate copolymer, acrylonitrile / butadiene copolymer, methyl methacrylate / butadiene copolymer, and styrene / butadiene copolymer can be used.

  If necessary, natural fibers such as cellulose fibers, protein fibers such as wool, silk thread and collagen fibers, chitin / chitosan fibers, or alginic acid fibers may be blended in addition to the synthetic fibers. Preferred natural fibers are cellulose fibers, such as chemical pulp, mechanical pulp, semi-chemical pulp, waste paper pulp, deinked pulp, powdered cellulose, chemically modified cellulose such as oxidized cellulose, and cellulose nanofiber: CNF (microfibrillation) Cellulose: MFC, TEMPO oxidized CNF, phosphate esterified CNF, carboxymethylated CNF, mechanically pulverized CNF, and the like).

Other Materials The dry nonwoven fabric of the present invention may contain one or more other materials as necessary in addition to the composite and synthetic fibers. 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 dry 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.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. Unless otherwise specified in the present specification, concentrations and parts are based on weight, and numerical ranges are described as including the end points.

Experiment 1: Production of dry nonwoven fabric (1) Synthesis of composite of hydrotalcite and fiber 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) and NaOH (Wako Pure Chemical Industries) was prepared. Further, as the acid solution was prepared ZnCl ₂ (Wako Pure Chemical) and a mixed aqueous solution of AlCl ₃ (Wako Pure Chemical) (B solution).
・ Alkaline solution (A solution, Na ₂ CO ₃ concentration: 0.05M, NaOH concentration: 0.8M)
Acid solution (B solution, ZnCl ₂ concentration: 0.3M, AlCl ₃ concentration: 0.1M)
Cellulose fibers were used as the raw material fibers. Specifically, it contains hardwood bleached kraft pulp (LBKP, manufactured by Nippon Paper Industries) and softwood bleached kraft pulp (NBKP, manufactured by Nippon Paper Industries) at a weight ratio of 8: 2, and is a Canadian standard drainage using a single disc refiner (SDR). Pulp fibers with a degree adjusted to 390 ml were used.

Pulp fibers were added to the alkaline solution to prepare an aqueous suspension containing pulp fibers (pulp fiber concentration: 1.56%, pH: about 12.4). This aqueous suspension (pulp solid content 30 g) is put into a 10 L reaction vessel, and while stirring the aqueous suspension, an acid solution (B solution) is dropped to form a composite of hydrotalcite fine particles and fibers. Synthesized. The reaction temperature was 50 ° C., the dropping rate was 15 ml / min, and dropping was stopped when the pH of the reaction solution reached about 7-8. After completion of the dropwise addition, 30 minutes, and the reaction stirred to give Zn-based HT complexes _{(Zn 6 Al 2 (OH)} 16 CO 3 · 4H 2 O and complexes of pulp fibers).

  Furthermore, the Zn-based HT composite was treated with a copper chloride solution to obtain a Zn-based HT composite supporting copper. Specifically, an acid solution prepared by dissolving copper chloride was added to a Zn-based HT composite slurry (concentration 1.56%) so that the 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 3 times the amount of water.

(2) Evaluation of composites Based on JIS P 8222, mats were produced from the synthesized Zn-based HT composites (basis weight: about 100 g / m ² ). Specifically, an aqueous slurry of Zn-based HT complex (about 0.5%) was filtered using filter paper (JIS P3801, for quantitative analysis, 5 types B), and the obtained sample was pressured at 1 MPa for 5 minutes. And dehydrated 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 deposited on the fiber surface. The area ratio of the portion covered with 25) was 25%, the primary particle diameter of fine particles: 200 to 500 nm, and the average primary particle diameter: 300 nm.

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

(3) Production of dry nonwoven fabric (Sample 1: Example)
30 parts by mass of the above Zn-based HT composite and 70 parts by mass of core-sheath composite fiber (fiber diameter: 2 dtex, fiber length: 40 mm, core / sheath: polypropylene / polyethylene) are mixed and charged into a card machine. A fiber accumulation layer (nonwoven web) was formed by a random web method. This nonwoven web was heat-treated at 140 ° C. and a part of the thermoplastic fiber was melted by a thermal bond method to produce a dry nonwoven fabric.

(Sample 2: Example)
A dry nonwoven fabric was produced in the same manner as Sample 1, except that 20 parts by mass of the Zn-based HT composite and 80 parts by mass of the core-sheath fiber were used as raw materials.

(Sample 3: Comparative example)
A dry nonwoven fabric was produced in the same manner as Sample 1, except that pulp fibers (kraft pulp used for synthesizing the composite fibers, Canadian standard freeness: 390 ml) were used instead of the Zn-based HT composite.
(Sample 4: Example)
Each of the above Zn-based HT composite and uncombined pulp (NBKP) was defibrated with a hammer mill, and a non-woven web was formed by mixing 50 parts by mass by the air array method. A binder (carboxymethylcellulose sodium salt) was applied to both sides of this nonwoven web at about 1.0 g / m ² per side to produce a dry nonwoven fabric.
(Sample 5: Example)
A non-woven web (first layer) having a basis weight of 10 g / m ² is prepared from rayon fibers (fineness 1.5 decitex, fiber length: 5 mm) using a card machine, and then a basis weight of 20 g / m ² is applied on the web. Thus, a Zn-based HT composite was supplied by the air array method (second layer), and a non-woven web (third layer) produced in the same manner as the first layer was laminated. While transporting the obtained laminate at a transport speed of 20 m / min, a 40 g / m ² dry nonwoven fabric in which the constituent fibers are entangled is obtained by performing high-pressure water flow treatment with water jet (treatment water pressure 7 MPa) from both sides. It was.
(Sample 6: Comparative example)
A dry nonwoven fabric was produced in the same manner as Sample 4 except that pulp fibers (kraft pulp used for synthesizing the composite fibers, Canadian standard freeness: 390 ml) were used instead of the Zn-based HT composite.
(Sample 7: Comparative example)
A dry nonwoven fabric was produced in the same manner as Sample 5, except that pulp fibers (kraft pulp used for synthesizing the composite fibers, Canadian standard freeness: 390 ml) were used instead of the Zn-based HT composite.

(4) Physical properties of dry nonwoven fabric The physical properties of the obtained dry nonwoven fabric were evaluated based on the following procedures.
-Basis weight: JIS P 8124: 1998
・ Thickness: JIS P 8118: 1998
-Density: Calculated from measured values of thickness and basis weight-Air permeability resistance: JIS P 8117: 2009

Experiment 2: Evaluation of dry nonwoven fabric (1) Evaluation of deodorizing characteristics The nonwoven fabric manufactured in Experiment 1 was evaluated for its deodorizing characteristics. All sheets subjected to the deodorization test were 1 g.

  The deodorization test is conducted based on the method of SEK Mark Textile Product Certification Standard (JEC301, Textile Evaluation Technology Council) and evaluates the deodorization 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.

The sample was conditioned at 20 ° C. and 65% RH for 24 hours or longer, and then the deodorizing characteristics (reduction rate,%) of the odor components were evaluated. Here, the reduction rate (%) can be obtained from the initial concentration of the odor component and the concentration at the time of measurement by the following equation.
Decrease rate (%) = (Blank test concentration-Measurement concentration / Blank test concentration) x 100
(2) Evaluation of antibacterial properties The antibacterial properties of the nonwoven fabric produced in Experiment 1 were evaluated. The antibacterial test was performed by the bacterial solution absorption method (quantitative test method in which the test inoculum was directly inoculated on the test piece) as defined in JIS L1902. Two types of Staphylococcus aureus NBRC 12732 and Escherichia coil NBRC 3301 were used as test strains, and the viable cell count after 18 hours of culture was measured by the pour plate culture method. A standard cotton cloth was used as a reference. The test procedure is shown below.
1. 0.4 g of the test piece is put in a vial, 0.2 ml of a test bacterial solution (containing 0.05% surfactant (Tween 80)) is dropped, and then the vial is covered.
2. The vial is incubated at 37 ° C. for 18 hours.
3. 20 ml of the washing solution is added to wash out the test bacteria from the test piece, and the number of viable bacteria in the washing solution is measured by the pour plate culture method or the 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 killing rate of bacteria is 99% or more.

Antibacterial activity value = {log (control sample / viable count after culture)-log (control sample / viable count immediately after inoculation)}-{log (test sample / viable count after culture)-log (test sample / viable count immediately after inoculation) number)}
(3) Evaluation of antiviral properties The nonwoven fabric produced in Experiment 1 was evaluated for antiviral properties. The antiviral test was carried out by an antiviral test method for JIS L 1922: 2016 textiles. The composite mat used in the test weighed 0.4 g, and a standard cotton cloth was used as a control sample. Feline calicivirus (Strain: F-9 ATCC VR-782) was used as a test virus species. The test procedure is shown below.
1. Place 0.4 g of the test piece in a vial, drop 0.2 ml of the test virus solution, and then close the vial.
2. The vial is left at 25 ° C. for 2 hours.
3. The virus is washed out from the test piece by adding 20 ml of the washing solution, and the infectivity titer is calculated by the plaque measurement method.
4). The antiviral activity value (Mv) is calculated by the following formula. In JIS, the antiviral effect is determined to be 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): logarithmic value of infectivity after 2 hours of action of control sample (average value of 3 samples)
Log (Vc): Logarithmic logarithm of infectivity after 2 hours of action of antiviral sample (average value of 3 samples)
(4) Evaluation result Although an evaluation result is shown in the following table, the dry nonwoven fabric (samples 1-2) which concerns on this invention showed high deodorizing ability with respect to an odor component. In addition, the dry nonwoven fabric according to the present invention exhibited excellent antibacterial and antiviral properties.

Claims (14)

  A dry nonwoven fabric comprising a composite of inorganic particles and fibers, wherein 15% or more of the fiber surface of the composite is covered with inorganic particles.   The nonwoven fabric according to claim 1, comprising a composite of inorganic particles and fibers and a binder.   The nonwoven fabric according to claim 1 or 2, comprising a composite of inorganic particles and fibers and a synthetic fiber.   The nonwoven fabric in any one of Claims 1-3 whose average primary particle diameter of an inorganic particle is 1 micrometer or less.   The nonwoven fabric in any one of Claims 1-4 whose weight ratio of the fiber and inorganic particle in a composite_body | complex is 5 / 95-95 / 5.   The nonwoven fabric in any one of Claims 1-5 whose fiber which comprises a composite_body | complex is a cellulose fiber.   The nonwoven fabric in any one of Claims 1-6 whose said cellulose fiber is a pulp derived from wood.   The nonwoven fabric according to any one of claims 1 to 7, wherein the inorganic particles are hydrotalcite.   The nonwoven fabric according to claim 8, wherein the hydrotalcite has magnesium or zinc as a divalent metal ion.   The nonwoven fabric according to claim 8 or 9, wherein the hydrotalcite has aluminum as a trivalent metal ion.   The nonwoven fabric according to any one of claims 1 to 10, for use in sanitary goods.   The nonwoven fabric in any one of Claims 1-11 for using for a mask or a wiper.   The nonwoven fabric according to any one of claims 1 to 12, which is used for deodorization, antibacterial use or antiviral use. A method for producing the dry nonwoven fabric according to any one of claims 1 to 13,
The said method including the process of forming a nonwoven fabric by the dry process from the raw material containing the composite_body | complex of an inorganic particle and a fiber.