JP2009007723A - Water-absorbing and water-dispersing paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide water-absorbing and water-dispersing paper having excellent liquid absorptivity, also having a high surface strength on being wet, capable of being dispersed with water flow after its use, and also having a deodorization function against bad smelling substances. <P>SOLUTION: This water-absorbing and water-dispersing paper having both of water-dispersing property and water absorptivity, and having a high surface strength on being wet, and also deodorization capacity is obtained by stacking a liquid-absorbing layer containing a complex fiber obtained by forming a polymer electrolyte complex with a cationic water soluble polymer in at least a part of a fibrous carboxyalkylcellulose and a surface layer containing water-dispersing fibers, or the water-dispersing fibers and water soluble fibers at least on one side, and laminating them by joining together in papermaking to make a sheet like material, and then incorporating an alkaline compound and a deodorizing agent to the whole or a part of the sheet like material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water-absorbing water-dispersed paper suitable for an antifouling sheet or the like that can be laid at a droplet scattering site such as filth to absorb the droplet, and can be dispersed and washed away with flush water or the like in a flush toilet after use.

  Conventionally, as a sheet for absorbing droplets, a laminated sheet of thin paper such as tissue paper or a nonwoven fabric, a laminated sheet in which a superabsorbent resin is added between paper or nonwoven fabric, and the like have been used. These absorbent sheets are used in a wide variety of applications, including drip absorption of food, condensation water absorption in cargo containers, freshness of vegetables and fresh fish, and components of disposable diapers and sanitary products. Various proposals have been made.

  For example, Patent Document 1 proposes a water absorbent sheet for transporting fresh products in which a thermoplastic resin and a water absorbent resin are sandwiched and fixed between two base papers, at least one of which is made of stretched paper.

  Patent Document 2 discloses a sewage water absorbing sheet in which a water absorbing resin is sandwiched and fixed between two water absorbing nonwoven fabrics such as Japanese paper.

  Patent Document 3 discloses a water-absorbing sheet in which a water-absorbing resin is fixed to a base paper with a reactive hot-melt adhesive as means for preventing the water-absorbing resin from falling off after water absorption, which is a drawback of conventional water-absorbing sheets.

  Patent Document 4 discloses a water-absorbing sheet obtained by paper-making a water-absorbing fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of a fibrous carboxyalkyl cellulose salt.

  Patent Document 5 discloses water absorption in which a polyelectrolyte complex of a cationic water-soluble polymer is formed on at least a part of a surface layer composed of a crosslinked carboxyalkyl cellulose and a fibrous carboxyalkyl cellulose water-soluble salt. A water-absorbing sheet is disclosed in which a liquid-absorbing layer containing a conductive fiber is laminated by sheet bonding.

  Moreover, about the water absorption sheet | seat which can be thrown away and washed to a flush toilet etc. after use, in patent document 6, the water absorption layer which consists of toilet paper which can be poured into a flush toilet, and the non-water absorption layer which consists of a saucer-like hard member and cannot be poured into a flush toilet A urine collection mat having a two-layer structure is disclosed.

  Patent Document 7 discloses a water-absorbing sheet obtained by mixing water-absorbing fibers and water-soluble fibers, a plurality of water-resistant pressure-sensitive adhesives formed so as to be scattered in an island shape on one surface of the water-absorbing sheet, and further water absorbing A water-absorbing sheet for toilets provided with a water-resistant printed pattern formed independently on the other surface of the sheet is disclosed. When the water-absorbing sheet is poured into water after use, the water-absorbing sheet is finely dispersed at the bottom surface where no adhesive layer is formed or at the position where there is no printed pattern because the water-soluble fibers dissolve.

JP-A-5-31856 Japanese Patent Laid-Open No. 11-227085 JP 2001-158074 A Japanese Patent No. 2891803 (Japanese Patent Laid-Open No. 5-106190) Japanese Patent No. 3326325 (Japanese Patent Laid-Open No. 9-239903) JP 2002-165729 A Japanese Patent No. 3692324 (Japanese Patent Laid-Open No. 2003-210359)

  However, since the water-absorbent sheets disclosed in Patent Documents 1 to 5 use water-insoluble paper or nonwoven fabric as the base paper, the sheet form does not collapse even when thrown in water, and water dispersibility and water solubility It does not have. In addition, the water-absorbing resin and water-absorbing fibers used maintain water absorption and swelling even after being thrown into water, which causes drainage problems such as strainers such as piping clogged with swollen gel. .

  Further, the urine collection mat proposed in Patent Document 6 is a thin paper such as toilet paper and has a small water absorption amount, and the water absorption layer itself has a low rigidity. It is necessary to take a two-layer structure in which a non-water-absorbing layer that cannot flow is used as a tray, and cannot be said to be a sheet having both water-absorbing properties and water-dispersibility.

  In the water absorbent sheet for toilets disclosed in Patent Document 7, a water-resistant adhesive and a printed pattern are formed on each of the front and back surfaces of the water absorbent sheet. For this reason, since the water absorbing sheet includes a portion that is insoluble in water, there is a concern that if the sheet is passed through the toilet as it is, it may cause clogging or increased load on the sewage facility. In other words, although it can be dispersed into small island-shaped pieces by running water from the flush toilet after use, the water-resistant part remains as it is, so it accumulates without being treated in the sewage pipe or sewage treatment plant, and the treatment load of the sewage treatment facility is increased. An increase is assumed.

  The present invention was made to solve the conventional problems as described above, has a high liquid absorption capability, and has a high surface strength when wet, and after use, it is dispersed / dissolved with a large amount of water flow. It is to provide a water-absorbing water-dispersed paper that can be used.

  In the present invention, by incorporating an alkaline compound into the swellable structure as described in Patent Document 4, not only the water absorption ability of the swellable structure is improved, but also the swellable structure is incorporated into a large amount of water. This is based on finding the phenomenon that the original shape collapses when dispersed and dissolved.

  The present inventors utilize the above phenomenon and laminate a surface layer for improving the surface strength when wetted with water droplets or wrinkles on at least one side of the liquid absorbing layer composed of the swellable structure by sheeting. The above problems were solved and the present invention was completed by adding an alkaline compound to the whole or a part of the formed sheet to impart a high liquid absorption capacity and dispersion / solubility in water.

  That is, according to the present invention, a liquid-absorbing layer comprising a complex fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of fibrous carboxyalkyl cellulose, and water dispersion on at least one side thereof Since the alkaline compound is contained in the whole or part of the sheet-like material in which the water-soluble or water-soluble surface layer is laminated by sheet-bonding, it has both water absorption and water dispersibility, and has a wet surface strength. High water-absorbing water-dispersed paper can be obtained.

  The water-absorbing water-dispersed paper of the present invention has an excellent liquid-absorbing property and has a high surface strength when wet, and can be dispersed in a water stream after use, so that temporary absorption of urine and disposal in water after use are possible. It can be used in a wide range of fields that require disposal in water after liquid absorption, such as the intended antifouling sheet. Moreover, since the deodorizing ability can be imparted without impairing the above characteristics, it can be suitably used for applications that absorb sewage that produces odors such as antifouling sheets.

  Hereinafter, the present invention will be described in detail. FIG. 1 schematically shows the basic structure of the water-absorbing water-dispersed paper according to the present invention. The water-absorbing water-dispersed paper 1 has a surface layer 21 laminated on at least one surface of the liquid-absorbing layer 11 by sheet-bonding, and the liquid-absorbing layer 11 includes complex fibers 12 that are mainly liquid-absorbing, The surface layer 21 includes water-soluble fibers 22 and water-dispersible fibers 23.

  In the present invention, the liquid-absorbing layer includes a complex fiber in which a polymer electrolyte complex with a cationic water-soluble polymer is formed on at least a part of the fibrous carboxyalkyl cellulose. The liquid layer is converted into a corresponding fibrous carboxyalkyl cellulose salt by the alkaline compound added after the lamination lamination with the surface layer, and has a water absorption property.

  Examples of the fibrous carboxyalkyl cellulose serving as the complex fiber substrate include fibrous carboxymethyl cellulose and fibrous carboxyethyl cellulose. The degree of etherification of fibrous carboxyalkyl cellulose, which is closely related to water absorption when it is poured into water absorption or water, is 0.1 to 1.0, preferably 0.3 to 0.8, more preferably 0.4. ~ 0.6.

  The cationic water-soluble polymer added to form a polyelectrolyte complex on the fibrous carboxyalkyl cellulose is a polymer compound having a basic group in the molecule. It is a water-soluble polymer comprising a repeating unit having at least one selected from secondary nitrogen atoms. An example of such a cationic water-soluble polymer is a natural polymer compound chitosan, and the synthetic polymer has a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer. There are a polymer (1) and a polymer (2) having a primary, secondary, tertiary or quaternary nitrogen atom in the main chain of the polymer.

  One example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer is (1-a) a primary, secondary, tertiary or quaternary nitrogen atom. And a homopolymer of a monomer having a polymerizable group such as a vinyl group, that is, a homopolymer of the following monomers. N, N-dialkylvinylamine, vinyltrialkylammonium, N-alkylaminoalkyl acrylate, N-alkylaminoalkyl methacrylate, N-alkylaminoalkyl acrylamide, N-alkylaminoalkyl methacrylamide, N, N-dialkylaminoalkyl Acrylate, N, N-dialkylaminoalkyl methacrylate, N, N-dialkylaminoalkylacrylamide, N, N-dialkylaminoalkylmethacrylamide, acryloyloxyalkyltrialkylammonium, methacryloyloxyalkyltrialkylammonium, acrylamidealkyltrialkylammonium , Methacrylamide alkyltrialkylammonium, vinyloxyalkylamine, N Alkyl vinyloxy alkyl amine, N, N-dialkyl vinyloxy alkyl amine, N, N, N- trialkyl-vinyloxy monomers such as alkyl ammonium. In these monomers, the alkyl group has 1 to 4 carbon atoms, an alkanol group may be introduced instead of the alkyl group, and instead of one alkyl group bonded to the nitrogen atom of the quaternary ammonium salt. It may be one into which an alkoxycarbonylalkylene group has been introduced. A specific example of a homopolymer of the above monomer is poly (methacryloyloxyethyltrimethylammonium chloride).

  Another example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer is (1-b) primary, secondary, tertiary or quaternary nitrogen atom. In addition, it is a copolymer of a monomer having another polymerizable group and another monomer, that is, a copolymer of the monomer mentioned in the above (1-a) and another monomer. Other monomers include acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, alkyl acrylate, alkyl methacrylate, vinyl acetate, styrene, α-methylstyrene, 4-vinylpyridine, 2-vinylpyridine and the like. A specific example of the copolymer is poly (3-acrylamide-3-methylbutyltrimethylammonium chloride-CO-acrylamide).

  As another example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer, (1-c) a homopolymer such as polyacrylamide is modified by Mannich modification or Hoffmann decomposition. Some are cationized by reaction.

  The polymer (2) having a primary, secondary, tertiary or quaternary nitrogen atom in the main chain of the polymer includes (2-a) ionene polymer, (2-b) polyethyleneimine, (2- c) Polyamine resins in a narrow sense and (2-d) other condensation polymers.

  The (2-a) ionene polymer is a polymer having an ionic amino group, particularly a quaternary ammonium group, in the main chain, and most of the nitrogen atoms are quaternized. For example, (2-a) -I) a polyadduct of a dihalo compound having a halogen atom at both ends of the molecule and a ditertiary amine having a tertiary nitrogen atom at both ends of the molecule, (2-a-ii) epichlorohydrin 2 per mole of the primary amine A polyadduct of a polymerizable precursor produced by ring-opening addition of a mole (a tertiary amine having a chlorine group at both ends of the molecule) and a di-tertiary amine having a tertiary nitrogen atom at both ends of the molecule, (2-a -Iii) 1 mol of epichlorohydrin is added to 1 mol of secondary amine by ring-opening addition, and a compound having a chlorine atom at one molecular end and a tertiary nitrogen atom at the other molecular end is polyadded. The resulting polymer.

  (2-b) Polyethyleneimine is a polymer produced by ring-opening polymerization of ethyleneimine, and has primary, secondary and tertiary nitrogen atoms in the main chain and branched main chain.

  (2-c) Although the academic definition of polyamine resin has not been established, in a narrow sense, for example, primary, secondary, tertiary, and quaternary nitrogen atoms are included, and quaternized nitrogen atoms are the total number of nitrogen atoms. It is defined as less than half, and is distinguished from the ionene polymer in that it has few quaternized nitrogen atoms. Examples include the following: (2-c-i) a polyamine resin which is a polymer obtained by polycondensing a compound obtained by ring-opening addition of 1 mol of epichlorohydrin to 1 mol of a primary amine while suppressing generation of a quaternary nitrogen atom, and a hydrochloride thereof, (2-c-ii) polyamine resin which is a polycondensate of alkylenediamine and epichlorohydrin, (2-c-iii) polyamine resin which is a polycondensate of alkylenediamine and alkylene dihalide.

  (2-d) Other condensation polymers include (2-d-i) polyamine polyamides that are polycondensates of alkylene polyamines and dicarboxylic acids, such as polycondensates of diethylenetriamine and adipic acid, (2-d-ii) ) When epichlorohydrin and dimethylamine are further added to the polyamine polyamide, the chlorine group of epichlorohydrin is added to the amide group of the polyamine polyamide to quaternize, and epichlorohydrin is ring-opened to dimethylamine. Thus, a polymer having secondary, tertiary and quaternary nitrogen atoms in the main chain and a tertiary nitrogen atom in the side chain is obtained.

  Furthermore, in the above-mentioned chitosan, homopolymer, copolymer, modified product, etc., a polymer obtained by quaternizing a primary, secondary or tertiary nitrogen atom with a quaternizing agent is also a cationic water-soluble polymer. A quaternizing agent can introduce an alkyl group or an alkoxycarbonylalkylene group into a primary, secondary or tertiary nitrogen atom. Alkyl halides such as methyl chloride, ethyl chloride and methyl bromide, dimethyl sulfate, chloro Such as methyl acetate. The quaternization reaction may be conducted after the repeating unit is in the monomer stage, or after polymerization, the repeating unit in the polymer may be subjected to quaternization by a polymer reaction.

  The cationic water-soluble polymer has a highly reactive functional group that generates a crosslink other than primary, secondary, tertiary, or quaternary nitrogen atoms, such as a glycidyl group, an aldehyde group, a carboxyl group, a vinyl group, It is desirable that an allyl group, an N-methylol group, a thiol group, an isocyanate, an isothiocyanate and the like are not substantially contained. This is to prevent the cationic water-soluble polymer from forming a covalent bond cross-link other than forming a polyelectrolyte complex with the fibrous carboxyalkyl cellulose. The term “substantially free” means that the covalent crosslinking is not included to the extent that the formation of the polyelectrolyte complex is not inhibited or reduced.

  The cationic water-soluble polymer has a cation equivalent of 0.1 to 20 meq / g, preferably 1 to 15 meq / g, more preferably 2 to 10 meq / g in the range of pH 3-9. The (number) average molecular weight is 5000 to 100,000, preferably 5000 to 70000, and more preferably 5000 to 20000.

  The addition amount of the cationic water-soluble polymer to the fibrous carboxyalkyl cellulose is within the range corresponding to the cation equivalent of 0.01 to 100% of the anion equivalent of the fibrous carboxyalkyl cellulose. An appropriate amount is selected depending on the type of molecule. By adding an amount of the cationic water-soluble polymer in this range, a polyelectrolyte complex is formed in the fibrous carboxyalkyl cellulose. The polyelectrolyte complex is a complex that is considered to be formed mainly through a Coulomb force between a fibrous carboxyalkyl cellulose having an opposite charge and a cationic water-soluble polymer. Although the details of the structure are not clear, cationic water-soluble polymers are ion-crosslinked between the molecules of fibrous carboxyalkyl cellulose, and cationic water-soluble polymers are close to the molecular chain of fibrous carboxyalkyl cellulose. The structure etc. which can be considered are considered.

  The fibrous carboxyalkyl cellulose that has become a complex fiber due to the formation of the polyelectrolyte complex swells while maintaining the fiber form when converted to the corresponding salt by an alkaline compound, and becomes a fibrous gel. To have.

  In addition to the complex fiber, the liquid absorbing layer preferably contains water-dispersible fibers in order to improve papermaking properties, wet strength, and cost.

  The water dispersible fiber can be selected from various natural fibers, semi-synthetic fibers, and synthetic fibers. Natural fibers include plant pulp fibers such as wood pulp and non-wood pulp, regenerated cellulose fibers such as viscose rayon having an average fiber length of 20 mm or less, and purified cellulose fibers such as lyocell having an average fiber length of 20 mm or less. Semi-synthetic fibers include acetate and promix fibers with an average fiber length of 20 mm or less. Synthetic fibers include, for example, short fibers having an average fiber length of 20 mm or less, polyester fibers having an average fiber length of 20 mm or less, polyolefin fibers, and the like using biodegradable thermoplastic resins such as polyvinyl alcohol, polylactic acid, and polybutylene succinate. Non-biodegradable synthetic fibers and the like can also be included in the water-dispersible fibers when used at a temperature lower than the heat fusion temperature between the fibers. The above-described non-biodegradable synthetic fibers must be blended by selecting an appropriate amount within a range that does not impair the water dispersibility and biodegradability of the water-dispersed paper.

  Furthermore, fibrous carboxyalkyl cellulose water-insoluble salts such as aluminum salts, iron salts, copper salts, cobalt salts, zinc salts, tin salts, lead salts, barium salts, and manganese salts of fibrous carboxyalkyl celluloses are also water-dispersible fibers. Can be included. These fibrous carboxyalkyl cellulose water-insoluble salts have a deodorizing effect on ammonia, amine, and sulfur-based malodorous substances. The base saturation of the fibrous carboxyalkyl cellulose insoluble salt (the ratio of the carboxyl group that has become a salt) is 2 to 50%, preferably 10 to 40%, and more preferably 20 to 30%.

  The ratio of the water-dispersible fiber and the complex fiber blended in the liquid absorbing layer is water-dispersible fiber / complex fiber = 0 to 90/100 to 10% by weight. The liquid-absorbing layer may be composed only of complex fibers without containing water-dispersible fibers, while the blending ratio of water-dispersible fibers is 90% by weight or less, desirably 60% by weight or less, Desirably, it is 40 weight% or less. When the mixing ratio of the water-dispersible fiber exceeds 90% by weight, the water absorption ability by the complex fiber is lowered, which is not preferable.

  In addition to this, the liquid-absorbing layer, if necessary, starch-based, polyacrylamide-based paper strength enhancers, wetting agents such as sucrose fatty acid esters, white or colored fillers or dyes / pigments that are usually used for papermaking Can be added.

The liquid-absorbing layer composed of the above components is thus formed by paper-making a complex fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of the fibrous carboxyalkyl cellulose. However, when water-dispersible fibers and the like are blended, papermaking properties are further improved. The basis weight of the liquid absorbing layer needs to be larger than the basis weight of the surface layer, and is 30 to 200 g / m ² , preferably 50 to 120 g / m ² , and more preferably 60 to 100 g / m ² . The absorbent layer is made as a single-layer sheet with a single mesh, and multiple wet paper sheets are made with two or more meshes to create a large basis weight absorbent layer. can do. In this case, it is also possible to change the blending ratio of the complex fiber and the water-dispersible fiber for each layer constituting the liquid absorption layer.

  The present invention is characterized in that a surface layer made of water-dispersible and water-soluble fibers is laminated on at least one surface of the liquid-absorbing layer by sheet bonding. The surface layer needs to have appropriate wet strength and surface strength when wetted with water, and have a property of being easily dispersed and dissolved in a large amount of water. When the liquid absorbing layer is exposed without providing a surface layer, the swollen gel is exposed when wet with water, the paper surface feels bad, and the surface shape tends to collapse due to external forces, so it is practical Unsatisfactory due to poor nature.

  The water-dispersible fiber blended in the surface layer can be selected from various natural fibers, semi-synthetic fibers, and synthetic fibers. Natural fibers include plant pulp fibers such as wood pulp and non-wood pulp, regenerated cellulose fibers such as viscose rayon having an average fiber length of 20 mm or less, and purified cellulose fibers such as lyocell having an average fiber length of 20 mm or less. Semi-synthetic fibers include acetate and promix fibers with an average fiber length of 20 mm or less. Synthetic fibers include, for example, short fibers having an average fiber length of 20 mm or less, polyester fibers having an average fiber length of 20 mm or less, polyolefin fibers, and the like using biodegradable thermoplastic resins such as polyvinyl alcohol, polylactic acid, and polybutylene succinate. Non-biodegradable synthetic fibers and the like can also be included in the water-dispersible fibers when used at a temperature lower than the heat fusion temperature between the fibers. Furthermore, fibrous carboxyalkyl cellulose water-insoluble salts such as aluminum salts, iron salts, copper salts, cobalt salts, zinc salts, tin salts, lead salts, barium salts, and manganese salts of fibrous carboxyalkyl celluloses are also water-dispersible fibers. Can be included. These fibrous carboxyalkyl cellulose water-insoluble salts have a deodorizing effect on ammonia, amine, and sulfur-based malodorous substances. The base saturation of the fibrous carboxyalkyl cellulose insoluble salt (the ratio of the carboxyl group that has become a salt) is 2 to 50%, preferably 10 to 40%, and more preferably 20 to 30%.

  The water-soluble fiber blended in the surface layer is fibrous carboxyalkyl cellulose, and specific examples include fibrous carboxymethyl cellulose and fibrous carboxyethyl cellulose.

  Fibrous carboxyalkyl cellulose has a free acid type carboxyalkyl group, and the degree of etherification closely related to water absorption and water solubility when poured in water is 0.1 to 1.0, preferably 0.3. It is -0.8, More preferably, it is 0.4-0.6. Since fibrous carboxyalkyl cellulose has a free acid type carboxyalkyl group, it is insoluble in water and does not gel, but an alkaline compound should be included in the sheet formed after the liquid-absorbing layer and the sheet-joining. Is converted into a corresponding water-soluble salt to form a water-soluble fiber.

  In addition, by partially containing an alkaline compound in the surface layer, part of the fibrous carboxyalkyl cellulose is converted into a water-soluble salt in an island pattern with an area of about 1 square centimeter or less so as not to impair the water dispersibility. If left untreated, it can function as a fibrous deodorant for removing these malodorous substances from the atmosphere by utilizing the reactivity of the fibrous carboxyalkyl cellulose with ammonia and amine-based malodorous substances.

  The type and mixing ratio of water-dispersible fibers and water-soluble fibers blended in the surface layer are determined by the target surface strength and tensile strength in the wet state, and the degree of water dispersibility and hydrophilicity imparted to the surface layer. Is done. Generally, the surface layer after containing an alkaline compound becomes easier to disperse and dissolve as the blending ratio of water-soluble fibers increases, while the surface strength and tensile strength in a wet state increase as the blending ratio of water-dispersible fibers increases. Becomes higher.

  In the surface layer, the formulation for combining moderate surface strength and water dispersibility is: water dispersible fiber / water soluble fiber = 100 to 70/0 to 30% by weight, desirably water dispersible fiber / water soluble fiber = 90 to 80/10 to 20% by weight, more desirably water dispersible fiber / water soluble fiber = 95 to 85/5 to 15% by weight.

  In addition to this, wetting agents such as starch-based, polyacrylamide-based paper strength enhancers, and sucrose fatty acid esters can be added to the surface layer as necessary. White or colored fillers and dye / pigment powders commonly used for papermaking can be added, but in the case of internal addition, agglomeration / fixing agent is added together with these powders, and the sheet is absorbed by water absorption. The powder must be prevented from falling off when rewet. As aggregation / fixing agents, polyacrylamides, polyacrylic acid sodas, polyethylene glycols and other high-molecular aggregation / fixing agents, aluminum sulfate, aluminum chloride, ferric chloride, ferric sulfate, and other inorganic aggregations -Natural polymer type aggregation / fixing agents such as fixing agents, cationic starches and chitosans can be used.

Since the surface layer needs to reinforce the low wet surface strength of the liquid-absorbing layer and increase the wet strength of the entire laminated sheet, the basis weight is 5 to 30 g / m ² , preferably 10 to 20 g / m ² . . When the basis weight is lower than 5 g / m ² , the wet strength is not sufficiently imparted, and when it exceeds 30 g / m ² , the ratio of the surface layer to the entire laminated sheet is increased, and the water absorption amount of the laminated sheet is unfavorably decreased.

  The structure of the laminated sheet is a two-layer structure in which one surface layer is laminated and bonded to one side of one liquid-absorbing layer, and one surface of each layer is drawn on both sides of one liquid-absorbing layer. In addition to the laminated and bonded three-layer structure, a plurality of, for example, two, three, four, and five liquid-absorbing layers with different water-dispersible fibers blended in the liquid-absorbing layer are laminated, and the surface layer is formed on one or both sides. Can be made of a multi-layered structure in which paper is bonded together.

  Thus, a laminated sheet is formed in which the surface layer and the liquid absorbing layer are joined together by combining, and an alkaline compound is subsequently added to the laminated sheet to neutralize the fibrous carboxyalkyl cellulose and corresponding fibrous carboxy. While converting into the alkylcellulose water-soluble salt, an excessive amount of an alkaline compound exceeding the neutralization equivalent is contained in the laminated sheet. By forming the fibrous carboxyalkyl cellulose water-soluble salt, the water dispersibility of the surface layer is greatly improved, and water absorption is imparted to the liquid absorbing layer. The excess alkaline compound contained in the laminated sheet becomes an alkaline aqueous solution when the sheet is poured into a large amount of water, and the fibrous carboxyalkyl cellulose and cationic water-soluble polymer of the liquid absorbing layer In order to dissociate the polyelectrolyte complex fiber, the liquid absorption layer is dispersed and dissolved in water.

  The alkaline compounds are listed below, and two or more kinds may be mixed and used. Alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Alkali metal carbonates and bicarbonates such as sodium carbonate, potassium carbonate and sodium bicarbonate. Phosphate and diphosphate of alkali metals such as sodium phosphate. Among group 2 element metal hydroxides such as calcium hydroxide and magnesium hydroxide, those which do not form water-insoluble salts. Amines such as ethanolamine, alkanolamines and ammonia.

  Regardless of the type of alkaline compound used, the amount of alkaline compound added should be equal to or greater than the neutralization equivalent of the fibrous carboxyalkyl cellulose contained in the surface layer for the surface layer to which the alkaline compound is added. It is. If the addition amount of the alkaline compound is less than the neutralization equivalent, the fibrous carboxyalkyl cellulose is not completely converted into a water-soluble salt, and the water dispersibility of the surface layer is lowered, which is not preferable.

  About a liquid absorption layer, it is necessary to make it 1.1 to 1.7 times the neutralization equivalent of the fibrous carboxyalkyl cellulose contained in the liquid absorption layer of the part to which the alkaline compound was added. If the amount of the alkaline compound is less than 1.1 times the neutralization equivalent of the fibrous carboxyalkyl cellulose, the amount of excess alkaline compound in the liquid absorption layer is insufficient, and the liquid absorption layer is poured into a large amount of water after use. In such a case, since the polymer electrolyte complex fiber of the fibrous carboxyalkyl cellulose and the cationic water-soluble polymer does not dissociate, the liquid absorption layer is not preferable because it retains the sheet form and does not disperse or dissolve in water. On the other hand, if the amount of the alkaline compound exceeds 1.7 times the neutralization equivalent of the fibrous carboxyalkyl cellulose, the excessive amount of the alkaline compound in the liquid-absorbing layer becomes excessive, and the droplets are absorbed during use. It is not preferable because the sheet form cannot be maintained until it is used after being dispersed and dissolved.

  In order to produce the water-absorbing water-dispersed paper according to the present invention, a polyelectrolyte is added to at least a part of the fibrous carboxyalkyl cellulose by adding a cationic water-soluble polymer to the fibrous carboxyalkyl cellulose dispersion. A complex fiber in which a complex is formed is prepared, and if necessary, water-dispersible fibers are blended to obtain a papermaking raw material, which is then made to prepare a liquid absorbent layer wet paper. Further, a water-dispersible fiber is blended with a dispersion of fibrous carboxyalkyl cellulose to make a papermaking raw material, and this is made to form a surface layer wet paper. The wet layer paper for the liquid-absorbing layer and the wet paper sheet for the surface layer are combined to form a two-layer wet paper, and the wet paper is heated and dried. A laminated sheet is prepared based on a method of heat-drying the wet paper as a three-layer wet paper by combining paper sheets so as to form both outer layers. For wet paper making, a paper making method generally used in the paper making technology described in JP-A-4-37536 can be used.

  Next, an alkaline compound solution is contained in the laminated sheet. These alkaline compounds are added in the form of an aqueous solution or an aqueous solution containing an organic solvent such as methanol or acetone. The method of adding to the laminated sheet is a method of squeezing the excess liquid with a pressure roll after immersing the laminated sheet in an aqueous solution of the above alkaline compound or a mixed solution of an aqueous organic solvent compatible with the aqueous solution, spraying Known methods such as a spraying method, a coating method using a roll coater, and a gravure printing method can be used. Moreover, you may add an alkaline compound so that the unprinted part of an area of about 1 square centimeter or less may be formed in a discontinuous island shape by a printing system. Thus, when the alkaline compound is printed in a pattern, the unprinted portion is poor in swelling and water dispersibility and improves the surface strength when wet, but the portion where the alkaline compound is continuously printed is dispersed. Since it melt | dissolves, the surface strength in a moist state increases and the laminated sheet which has water dispersibility is obtained.

  If necessary, the laminated sheet can be impregnated and coated with a processing agent such as a water-soluble or water-dispersible paper strength enhancer or a colorant. Examples of water-soluble or water-dispersible paper strength enhancers include starch, polyvinyl alcohol, carboxymethyl cellulose salt, alginic acid salt, various water-soluble gums, polyacrylamide, and polyacrylic acid ester copolymer. As the colorant, known materials such as fillers, dyes and pigments generally used for papermaking can be used.

  The processing agent can be added before or simultaneously with the addition of the alkaline compound to the laminated sheet, and the addition method is a printing method such as impregnation processing such as a size press, coating with a roll coater, spray spraying, gravure printing, etc. It can carry out by a well-known method.

  The deodorizing agent used in the present invention is required to have a characteristic that can exhibit a deodorizing action even in the presence of an alkaline compound and does not reduce the water absorption performance, water dispersibility, and wet surface strength of the laminated sheet. Further, it is necessary to have a deodorizing ability for at least one malodorous substance among basic malodorous substances such as ammonia and amine, and sulfur-based malodorous substances such as methyl mercaptan, dimethyl sulfide, and hydrogen sulfide. If it is a deodorizing agent which has such a characteristic, there will be no restriction | limiting in a deodorizing principle, Any deodorizing agents, such as an adsorption type and a chemical reaction type, can be used, and 2 or more types of deodorizing agents may be mixed and used.

  Examples of the deodorizer based on the adsorption action that can be used in the present invention include activated carbon, activated carbon fiber, zeolite, silica gel, activated clay, montmorillonite, barley stone, and the like, metal oxides such as aluminum oxide, titanium oxide, and zinc oxide, and dioxide dioxide. Examples thereof include a silicon / aluminum oxide / zinc oxide composite composition. The shape of these deodorizers includes powder, granules, fibers, etc., and there is no limitation on the shape.

  Examples of the deodorizer based on a chemical reaction that can be used in the present invention include a metal salt of a polycarboxylic acid or a metal chelate compound. The polycarboxylic acid is a compound having one or more carboxyl groups in one molecule and may have any molecular weight and may be a polymer electrolyte. Specific examples of the polycarboxylic acid include polyacrylic acid, polymethacrylic acid, alginic acid, carboxymethylcellulose, carboxyethylcellulose, polyacrylic acid crosslinked body, polymethacrylic acid crosslinked body, carboxylic acid type weakly acidic cation exchange resin, ethylenediaminetetraacetic acid Nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid and the like.

The metal salt or metal chelate compound of polycarboxylic acid is a salt or metal chelate compound of the above polycarboxylic acid and a polyvalent metal ion. As specific examples of the polyvalent metal ion, Fe ²⁺ , Fe ³⁺ , Cu ²⁺ , Al ³⁺ , Mg ²⁺ , Zn ²⁺ , Sn ⁴⁺ , Pb ²⁺ , Ba ²⁺ , Ca ^{2+ and the} like. Any one kind of these metal ions is usually used, but two or more kinds may be used simultaneously.

  The chemical reaction type deodorizer has powder, granule, fiber, and the like, but the shape is not limited and can be used in the same manner.

  Adsorption-type deodorant and chemical reaction-type deodorant can be added to the liquid-absorbing layer or surface layer by using papermaking raw materials and then embedding at the time of papermaking. In any method, the water absorption performance and water dispersibility of the water-absorbing water-dispersed paper of the present invention are not deteriorated. In addition, when adding a deodorizing agent after laminated sheet formation, the addition time of a deodorizing agent may be either before addition of an alkaline compound with respect to this laminated sheet, after addition, or simultaneous addition.

The addition amount of the deodorizing agent is 0.1 to 20 g / m ² , preferably ² to 10 g / m ² . If the addition amount is less than 0.1 g / m ² , the deodorizing ability is small and the practicality is poor. On the other hand, if the amount added exceeds 20 g / m ² , the deodorizer tends to fall off, which is not preferable. If necessary, the deodorizer may contain a water-soluble binder such as starch, polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, hydroxyethyl cellulose, a viscosity modifier, and the like.

  As another type of deodorizing agent that can be used in the water-absorbing water-dispersed paper of the present invention, an acidic compound can be mentioned. The acidic compound is effective for deodorizing a basic malodorous substance such as ammonia, and can convert the basic malodorous substance into an odorless substance by a neutralization reaction. When the water-absorbing water-dispersed paper of the present invention is used as the above-mentioned antifouling sheet, it is laid on the urine droplet splashing part of a male toilet and absorbs the urine droplets. The usage method is assumed. In this application, since basic malodorous substances such as ammonia are mainly used, the acidic compound can be effectively used as a deodorizing agent.

  However, when a strong acid such as sulfuric acid is used as the acidic compound, the fibrous carboxyalkyl cellulose water-soluble salt formed from the fibrous carboxyalkyl cellulose and the alkaline compound in the liquid absorption layer and the surface layer is hydrolyzed into the water-insoluble fibrous carboxyalkyl cellulose. Decomposes and loses water absorption and water dispersibility. Acidic compounds that do not cause hydrolysis by coexisting with the water-soluble salt of fibrous carboxyalkylcellulose must have lower acidity than carboxyalkylcellulose. Succinic acid, isophthalic acid, adipic acid, azelaic acid, malic acid, citric acid , Organic acids having a pka value of 3.0 or more such as glutaric acid and lactic acid, and weak hydrogen oxyhydrogen salts such as primary phosphates.

  It is necessary to apply the deodorizer composed of these acidic compounds in a pattern on one or both sides of the laminated sheet after the addition of the alkaline compound. The application pattern should be such that the application part having an area of about 1 square centimeter or less is formed in a discontinuous island shape, and the alkaline compound remains in the non-application part without being neutralized. Thus, when the deodorizer which consists of an acidic compound is apply | coated to pattern shape, although an alkaline compound is neutralized in an application part, since fibrous carboxyalkyl cellulose water-soluble salt remains as it is, water absorption is not lost. On the other hand, since there is no alkaline compound, the deodorant-applied part is poorly water-dispersible, but the deodorant-unapplied part, which is a continuous layer, contains an alkaline compound part and is dispersed and dissolved in water. Therefore, a water-absorbing water-dispersed paper having water absorbing properties, water dispersibility, and a deodorizing ability for basic malodorous substances is obtained.

  Examples of the application method of the deodorant made of an acidic compound include printing methods such as flexographic printing, gravure printing, and screen printing, a point spraying method using a powder spreader, and a point melt addition method using a hot melt applicator.

The coating amount of the deodorizer is 0.1 to 20 g / m ² , preferably ² to 10 g / m ² . If the coating amount is less than 0.1 g / m ² , the deodorizing ability is small and the practicality is poor. On the other hand, if the coating amount exceeds 20 g / m ² , the coating layer tends to fall off, which is not preferable. A water-soluble binder such as starch, polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, and hydroxyethyl cellulose, a viscosity adjusting agent, and the like can be blended with the deodorizing agent made of an acidic compound, if necessary.

  Examples of the water-absorbing water disintegrating paper according to the present invention are shown below. In each of the examples and comparative examples, the water absorption amount of the water-absorbing water-dispersed paper, the surface strength in a wet state, the water dispersibility, and the ammonia deodorizing ability are Evaluation was performed in the following manner in a test room set at a temperature of 23 degrees Celsius and a relative humidity of 50%. In the following examples, “parts by weight” and “% by weight” mean “parts by weight of solids” and “% by weight of solids”.

<Water absorption amount> A test piece of 10 cm × 12 cm is put in a 100-mesh wire mesh cage, dipped in 1000 ml of tap water for 15 minutes, then pulled up, suspended for one minute with one end facing upward, and then the test piece is dropped. The weight of was measured. The amount of water absorption was calculated by the following formula.
Water absorption (g / g) = [(Test piece weight g after removal of excess water) − (Test piece air dry weight g)] ÷ (Test piece air dry weight g)

<Wet surface strength> 5 drops of water droplets were dropped on the surface layer side of a 10 cm x 10 cm test piece with a 3 ml syringe, and after the water drops had penetrated into the paper, placed a finger and reciprocated 30 times without applying force. The degree of surface tearing and gelation when rubbed was observed and evaluated in five stages. Surface strength 1 is broken and surface shape collapses due to gelation, surface strength 2 is a state where gelation occurs and partial collapse of the surface shape is observed, and surface strength 3 is that the surface is slightly gelled. The state where the shape does not collapse, the surface strength 4 indicates that the surface is slimmed but is hardly gelled or broken, and the surface strength 5 indicates that the surface is not broken or gelled. In this evaluation, it has practical strength with a surface strength of 4 or more.

<Water dispersion time> Put 300 ml of deionized water in a 300 ml beaker, add one 3 cm square test piece while stirring at 650 rpm with a stirrer, and use a stopwatch to find the time for cutting the test piece into two or more pieces. The average value of the measurements was taken as the water dispersion time. The shorter the water dispersion time, the better the water dispersibility.

<Ammonia deodorizing ability> A 15 cm x 20 cm test piece was placed in a 300 ml Erlenmeyer flask and sealed with a silicone rubber stopper with a gas inlet, then ammonia standard gas was injected from the gas inlet with a gas tight syringe and the inside of the Erlenmeyer flask The initial gas concentration was 200 PPM. After 1 hour, a gas detection tube manufactured by Gastec Co., Ltd. was inserted into the Erlenmeyer flask from the gas inlet, the gas concentration (PPM) in the Erlenmeyer flask was measured, and the deodorization rate was calculated by the following formula. Ammonia deodorization rate (%) = 100−gas detector tube fixed concentration ÷ ammonia gas initial concentration × 100

(Production of liquid absorption layer)
Fibrous carboxymethyl cellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification 0.43, free acid type) was dispersed in water to prepare a dispersion having a concentration of 1.5%. Polyamine resin (manufactured by Sumitomo Chemical Co., Ltd., number average molecular weight 10,000, cation equivalent is 5.8 milliequivalent / g at pH 6 and contains quaternized nitrogen atoms and tertiary nitrogen atoms in the polymer main chain). A complex fiber obtained by adding 2.0% by weight to the fibrous carboxymethylcellulose and stirring, and various water-dispersible fibers as shown in the water-dispersible fiber column of the liquid-absorbing layer in Table 1, A predetermined weight part of each was blended to prepare a papermaking raw material for the liquid-absorbing layer, and a liquid-absorbing-layer wet paper having a basis weight of 60 g / m ² was produced.

(Preparation of surface layer)
Separately, using softwood bleached wood pulp beaten to a freeness of Canada of 680 CSF as a water-dispersible fiber, the surface layer wet paper having a basis weight of 10 g / m ² is prepared by dispersing in water and preparing a surface layer papermaking raw material. Produced.

(Production of laminated paper)
After layering the surface layer wet paper on one side of the liquid absorbent layer wet paper, pressurizing for 5 minutes at 3.5 kg / cm ² through the filter paper for squeezing, and then contacting the heating mirror plate of the rotary dryer and drying, A two-layer laminated paper was prepared.

  The obtained laminated paper was impregnated with sodium carbonate as an alkaline compound and dried in the same manner as described above with a rotary dryer to obtain the water-absorbing water-dispersed paper of the present invention. The addition amount of the alkaline compound to the handmade paper was 1.26 times the anion equivalent of the fibrous carboxymethylcellulose forming the complex fiber. The characteristics are shown in Table 1.

  The same procedure as in Example 1 except that the laminated paper produced in Example 1 was used and the amount of sodium carbonate added during impregnation was 1.30 times the anion equivalent of the fibrous carboxymethyl cellulose forming the complex fiber. The water-absorbing water-dispersed paper of the present invention was obtained.

  Using the laminated paper prepared in Example 1, using a 1: 1 mixture of sodium carbonate and sodium hydrogen carbonate as an alkaline compound during the impregnation process, the addition amount is 1.47 which is the anion equivalent of fibrous carboxymethyl cellulose forming a complex fiber. The water-absorbing water-dispersed paper of the present invention was obtained in the same procedure as in Example 1 except that the ratio was doubled.

  The water-absorbing water-dispersed paper of the present invention was obtained in the same procedure as in Example 3, but the anion of fibrous carboxymethyl cellulose forming complex fibers with the addition amount of 1: 1 mixture of sodium carbonate and sodium bicarbonate during impregnation processing 1.53 times equivalent

  The same procedure as in Example 1 except that the amount of sodium carbonate added during the impregnation process was 1.10 times the anion equivalent of the fibrous carboxymethyl cellulose forming the complex fiber, using the laminated paper prepared in Example 1. The water-absorbing water-dispersed paper of the present invention was obtained.

(Comparative Examples 1, 2, and 3)
Moreover, the above-mentioned ones without sodium carbonate and those having an addition amount of 1.05 and 1.78 times the anion equivalent of fibrous carboxymethylcellulose were also prepared, and the properties are shown in Table 3 as Comparative Examples 1 to 3, respectively. It was.

From Table 1, the double-layered laminated paper of Examples 1 to 5 has a water absorption as high as 18 times or more of its own weight (basis weight 70 g / m ² ), the wet surface strength is 5 and it is torn and gelled. The water dispersion time was 10 seconds or less, and the water dispersibility was excellent. On the other hand, when no sodium carbonate was added as in Comparative Example 1 in Table 3 or when the equivalent ratio of sodium carbonate added as in Comparative Example 2 was less than 1.10, the water absorption amount was extremely low, and the water dispersion time was Was extremely long and substantially free of water dispersibility. In addition, when the equivalent ratio of sodium carbonate added as in Comparative Example 3 exceeds 1.7, the water absorption amount and water dispersibility are excellent, but the surface strength when wet is weak, and the wet part melts and becomes a hole. Will open.

  From the above, the water-absorbing water-dispersed paper of the present invention has water-absorbing and water-dispersing properties as long as the amount of sodium carbonate added is in the range of 1.10 to 1.70 times the anion equivalent of fibrous carboxymethyl cellulose. It is clear that it has a wet surface strength that is high and does not collapse even when a small amount of water is wet.

(Production of liquid absorption layer)
Fibrous carboxymethyl cellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification 0.43, free acid type) is dispersed in water to give a cation-type water-soluble high dispersion in a 1.5% concentration. Cation type polyacrylamide resin (manufactured by Meisei Chemical Industry Co., Ltd., cation equivalent 4.5 meq / g, polymer side chain containing quaternized nitrogen atom) as a molecule is 2.0% by weight with respect to the fibrous carboxymethyl cellulose. A complex fiber obtained by adding and stirring at a ratio of% was prepared. Next, prepare an aqueous dispersion of bleached coniferous wood pulp beaten to a Canadian freeness of 680 CSF, blend each with a predetermined part by weight as shown in Table 2, and prepare a papermaking raw material for the liquid-absorbing layer. A 60 g / m ² absorbent layer wet paper was prepared.

(Preparation of surface layer)
Separately, fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., etherification degree 0.43, free acid type) and Canadian pulp freeness wood pulp beaten to Canadian freeness 680CSF in a ratio of 20:80 ( A mixed fiber raw material blended in (part by weight) and dispersed in water was prepared, and a surface layer wet paper having a basis weight of 10 g / m ² was prepared.

(Production of laminated paper)
After layering the surface layer wet paper on one side of the liquid absorbent layer wet paper, pressurizing for 5 minutes at 3.5 kg / cm ² through the filter paper for squeezing, and then contacting the heating mirror plate of the rotary dryer and drying, A two-layer laminated paper was prepared.

  The obtained laminated paper was impregnated with sodium carbonate as an alkaline compound and dried in the same manner as described above with a rotary dryer to obtain the water-absorbing water-dispersed paper of the present invention. The amount of sodium carbonate added to the laminated paper was 1.30 times the anion equivalent of fibrous carboxymethyl cellulose forming the complex fiber. The characteristics are shown in Table 2.

  The water-absorbing water-dispersed paper of the present invention was obtained in the same procedure as in Example 6, but the fiber composition of the surface layer was changed to fibrous carboxymethyl cellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification 0). .43, free acid form) and conifer bleached wood pulp beaten to a Canadian freeness of 680 CSF at a 30:70 ratio (parts by weight).

(Comparative Examples 4 and 5)
The water-absorbing water-dispersed paper was prepared in the same manner as in Examples 6 and 7 except that the blending ratio of the fibrous carboxymethyl cellulose in the surface layer was 40 parts by weight or 50 parts by weight. Indicated.

From Table 2, the double-layered laminated papers of Examples 6 and 7 have a water absorption as high as 25 times their own weight (basis weight 70 g / m ² ), and the wet surface strength is 4-5 and is broken or gelled. The water dispersion time was 5 seconds or less and the water dispersibility was excellent. On the other hand, as shown in Comparative Examples 3 and 4 in Table 4, when the water-soluble fiber content of the surface layer exceeds 30% by weight, the water absorption is high and the water dispersion time is short, but the surface strength when wet is low. It is weak and the wet part is torn or melted, resulting in a hole.

  From the above, the water-absorbing water-dispersed paper of the present invention has high water-absorbing and water-dispersing properties when the mixing ratio of the water-soluble fibers in the surface layer is in the range of 0 to 30% by weight. It is obvious that the surface morphology also has a wet surface strength that does not collapse.

(Production of liquid absorption layer)
Fibrous carboxymethyl cellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification 0.43, free acid type) was dispersed in water to prepare a dispersion having a concentration of 1.5%. Polyethyleneimine resin (manufactured by Nippon Shokubai Co., Ltd., number average molecular weight 70000, polymer main chain containing primary, secondary, and tertiary nitrogen atoms) is 0.03% by weight based on the fibrous carboxymethylcellulose. 50 parts by weight of the complex fiber obtained by adding and stirring at a ratio of 50 parts by weight and 50 parts by weight of bleached coniferous wood pulp beaten to a Canadian freeness of 680 CSF as a water-dispersible fiber, and the raw material for paper making of the liquid absorbing layer And a liquid-absorbent layer wet paper having a basis weight of 53 g / m ² was produced.

(Preparation of surface layer)
Separately, 20 parts by weight of fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., etherification degree 0.43, free acid type) and 80 weights of softwood bleached wood pulp beaten to Canadian freeness 680CSF A mixed fiber raw material in which parts were blended was prepared to prepare a surface layer wet paper having a basis weight of 27 g / m ² .

(Production of laminated paper)
After layering the surface layer wet paper on both sides of the liquid absorbent layer wet paper, pressurizing for 5 minutes at 3.5 kg / cm ² through the filter paper for squeezing, and then contacting the heating mirror plate of the rotary dryer and drying, A three-layer laminated paper was produced. The characteristics are shown in Table 5.

About the obtained laminated paper, using sodium carbonate as an alkaline compound, sodium carbonate / starch oxide (manufactured by Nippon Corn Starch Co., Ltd.) / Adsorption type deodorizer (manufactured by Daiwa Chemical Industry Co., Ltd., silicon dioxide / aluminum oxide / zinc oxide) (Composite composition) = 7/1 / 1.35 parts by weight of an aqueous solution was impregnated and dried with a rotary dryer to obtain the water-absorbing water-dispersed paper of the present invention shown in Example 8 in Table 5 It was. The amount of sodium carbonate added to the laminated paper was 1.60 times the anion equivalent of the fibrous carboxymethyl cellulose forming the complex fiber. Moreover, the addition amount of the adsorption type deodorizer was 1.5 g / m ² .

From Table 5, the three-layer laminated paper of Example 8 has a water absorption as high as 28 times its own weight (basis weight 107 g / m ² ), the wet surface strength is 5, and no tearing or gelation is observed. The water dispersion time was 8 seconds and the water dispersibility was excellent. Moreover, the ammonia deodorization rate was 60%, and the deodorizing action with respect to ammonia gas was seen. For these reasons, the three-layer laminated water-absorbing water-dispersed paper of the present invention has high water-absorbing and water-dispersing properties, and has a wet surface strength and a deodorizing ability that do not break down even when a small amount of water gets wet. It is obvious.

(Production of liquid absorption layer)
In the same manner as in Example 8, a liquid absorbent layer wet paper having a basis weight of 80 g / m ² was produced.

(Preparation of surface layer)
Separately, 10 parts by weight of fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., etherification degree 0.43, free acid type) and 80 weights of hardwood bleached wood pulp beaten to a Canadian freeness of 650 CSF And a mixed fiber raw material containing 10 parts by weight of rayon short fibers (1.7 dt × 5 mm) were prepared to prepare a surface layer wet paper having a basis weight of 30 g / m ² .

(Production of laminated paper)
After layering the surface layer wet paper on both sides of the liquid absorbent layer wet paper, pressurizing for 5 minutes at 3.5 kg / cm ² through the filter paper for squeezing, and then contacting the heating mirror plate of the rotary dryer and drying, A three-layer laminated paper was produced.

About the obtained laminated paper, using sodium carbonate as an alkaline compound, sodium carbonate / oxidized starch (manufactured by Nippon Corn Starch Co., Ltd.) / Chemical reaction type deodorant (polyiron acrylate (III) salt powder, polyacrylic acid carboxyl) The aqueous solution blended at a ratio of gram equivalent of iron (III) ion to group: 0.5) = 7/1/2 part by weight was impregnated and dried with a rotary drier, and shown in Example 9 in Table 5. A water-absorbing water-dispersed paper of the present invention was obtained. The amount of sodium carbonate added to the laminated paper was 1.49 times the anion equivalent of the fibrous carboxymethyl cellulose forming the complex fiber. Moreover, the addition amount of the chemical reaction type deodorizer was 2.5 g / m ² .

From Table 5, the three-layer laminated handmade paper of Example 9 has a water absorption as high as 32 times its own weight (basis weight: 140 g / m ² ), and the wet surface strength is 5 and tearing or gelation is observed. The water dispersion time was 4 seconds and the water dispersibility was excellent. Further, the ammonia deodorization rate was 99%, and it had an excellent deodorizing action on ammonia gas. For these reasons, the three-layer laminated water-absorbing water-dispersed paper of the present invention has high water-absorbing and water-dispersing properties, and has a wet surface strength and a deodorizing ability that do not break down even when a small amount of water gets wet. It is clear.

  In the same manner as in Example 8, a three-layer laminated type laminated paper was produced. The obtained laminated paper was impregnated with sodium carbonate as an alkaline compound, impregnated with an aqueous solution of sodium carbonate / oxidized starch (manufactured by Nippon Corn Starch Co., Ltd.) = 7/1 part by weight, and dried with a rotary dryer Thus, a water-absorbing water-dispersed paper was obtained. The amount of sodium carbonate added to the handmade paper was 1.60 times the anion equivalent of the fibrous carboxymethyl cellulose forming the complex fiber.

Next, a pattern in which a succinic acid is used as a deodorizing agent composed of an acidic compound and a coating solution having a composition of succinic acid / polyvinylpyrrolidone / ethyl alcohol = 15/3/82 parts by weight is dispersed in a circle having a diameter of 2 mm in a polka dot pattern. Then, gravure printing was performed on one side of the water-absorbing water-dispersed paper. The amount of succinic acid added was 4 g / m ² .

From Table 5, the three-layer laminated handmade paper of Example 10 has a water absorption as high as 25 times its own weight (basis weight 111 g / m ² ), the wet surface strength is 5, and tearing and gelation are observed. The water dispersion time was 8 seconds and the water dispersibility was excellent. Moreover, the ammonia deodorization rate was 99%, and an excellent deodorizing action against ammonia gas was observed. For these reasons, the three-layer laminated water-absorbing water-dispersed paper of the present invention has high water-absorbing and water-dispersing properties, and has a wet surface strength and a deodorizing ability that do not break down even when a small amount of water gets wet. It is clear.

Table 1 summarizes the characteristics of Examples 1 to 5.

Table 2 summarizes the characteristics of Examples 6 and 7.

Table 3 summarizes the characteristics of Comparative Examples 1 to 3.

Table 4 summarizes the characteristics of Comparative Examples 4 and 5.

Table 5 summarizes the characteristics of Examples 8-10.

  The water-absorbing water-dispersed paper according to the present invention has an excellent water-absorbing property, and in the disposal process, water-dispersing treatment is possible without increasing the load on the sewerage treatment facility, and the processing is a characteristic of paper. Since it is easy to handle, it is suitable for cleanliness maintenance in a place where wetting with water droplets or the like is likely to occur, and is particularly suitable for application to an antifouling mat for toilets, a mat for nursing care, and the like.

It is the cross-sectional schematic diagram which showed the structure of the water absorptive water dispersion paper of this invention which provided the surface layer in the single side | surface of an absorption layer.

Explanation of symbols

1 Water-absorbing water-dispersed paper 11 Water-absorbing layer 12 Complex fiber 21 Surface layer 22 Water-soluble fiber 23 Water-dispersible fiber

Claims (11)

A liquid-absorbing layer comprising a complex fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of a fibrous carboxyalkyl cellulose, and water dispersible and water-soluble fibers on at least one side thereof A water-absorbing water-dispersed paper, characterized in that an alkaline compound is contained in the whole or a part of a sheet-like material in which surface layers are laminated by sheet bonding. The water-absorbing water-dispersed paper according to claim 1, wherein the liquid-absorbing layer contains water-dispersible fibers. The water-absorbing water-dispersed paper according to claim 1, wherein the water-soluble fiber of the surface layer is fibrous carboxyalkyl cellulose. The water-absorbing water-dispersed paper according to claim 1 or 2, wherein the water-dispersible fiber is at least one selected from natural fibers, semi-synthetic fibers, and synthetic fibers. The water-absorbing water-dispersed paper according to any one of claims 1 to 4, wherein a part or all of the fibrous carboxyalkyl cellulose forms a water-soluble salt. Alkaline compounds selected from alkali metal and alkaline earth metal hydroxides, carbonates, bicarbonates, phosphates, diphosphates, borates, silicates, and ammonia, amines, alkanolamines The water-absorbing water-dispersed paper according to any one of claims 1 to 5, wherein the water-absorbing water-dispersed paper is at least one kind. A cationic water-soluble polymer has a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer and a primary, secondary, tertiary or quaternary nitrogen atom in the main chain of the polymer. The water-absorbing water-dispersed paper according to any one of claims 1 to 6, wherein the water-absorbing water-dispersed paper is at least one selected from polymers having the same. The water-absorbing water-dispersed paper according to any one of claims 1 to 7, wherein the water-absorbing water-dispersed paper contains at least one kind of deodorizing agent. The water-absorbing water-dispersed paper according to claim 8, wherein the deodorizing agent is a silicon dioxide / aluminum oxide / zinc oxide composite composition. The water-absorbing water-dispersed paper according to claim 8, wherein the deodorizing agent is a metal salt of a polycarboxylic acid or a metal chelate compound. The deodorizer is an organic acid having a pka value of 3.0 or more, such as succinic acid, isophthalic acid, adipic acid, azelaic acid, malic acid, citric acid, glutaric acid, lactic acid, or weak acid hydrogen salt such as primary phosphate The water-absorbing water-dispersed paper according to claim 8, wherein these deodorizing agents are applied in a discontinuous island pattern on one or both sides of the laminated sheet after addition of the alkaline compound.

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