JP2018083989A - Water-disintegrable sheet and method of producing the water-disintegrable sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet having improved tear resistance when rubbed with strong force while keeping the water water-disintegrable property.SOLUTION: The water-disintegrable sheet is obtained by impregnating a base paper sheet with an aqueous agent, wherein the base paper sheet has a basis weight of 30-150 gsm and contains a water-soluble binder and a carboxymethylated cellulose nanofiber, and the aqueous agent contains a crosslinking agent which crosslinks the water-soluble binder.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water-decomposable sheet impregnated with an aqueous chemical such as a toilet cleaner and a method for producing the water-decomposable sheet.

Conventionally, woven cloth cloths that are used repeatedly have been used for cleaning toilets, but instead of this, paper disposable water-decomposable sheets have been used in recent years. .
This type of water-decomposable sheet is provided in the state of being impregnated with a cleaning agent, and can be processed by flowing into a toilet after use.

  In such a water-decomposable sheet, it is required to ensure paper strength that does not break in a wet state impregnated with a cleaning agent at the time of wiping work, and water decomposability that does not clog pipes when flowing into a toilet or the like. However, as one technique for effectively achieving these, it is known to use a water-degradable sheet to which a water-soluble binder containing carboxymethyl cellulose (hereinafter referred to as CMC) is added as the base paper. (For example, refer to Patent Document 1).

Japanese Patent No. 3865506

By the way, the conventional water-decomposable sheet may be torn, for example, when the edge of a toilet bowl is rubbed strongly in toilet cleaning. However, when the coating concentration of the CMC solution is increased in order to improve the surface strength, the amount of the CMC solution entering the inside of the water-decomposable sheet increases and the water-decomposability is deteriorated.
Thus, in the water-decomposable sheet, there has been a demand for improving the resistance to tearing when rubbed strongly while ensuring the water-decomposability.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a water-decomposable sheet and a method for producing the water-decomposable sheet with improved water-disintegrability and improved resistance to tearing when rubbed strongly. And

In order to solve the above problems, the invention described in claim 1
A water-degradable sheet obtained by impregnating a base paper sheet with an aqueous drug,
The base paper sheet has a basis weight of 30 to 150 gsm, contains a water-soluble binder and carboxymethylated cellulose nanofibers,
The aqueous drug contains a cross-linking agent that cross-links with the water-soluble binder.

The invention according to claim 2
The water-decomposable sheet according to claim 1,
The base paper sheet is
A wear resistance test using a Gakushin type friction fastness tester using a PP band as a Gakuden pendulum was performed three times each in the MD direction and the CD direction, and the average of the three measured values was calculated. The value is 50 times or more.

The invention according to claim 3
A method for producing a water-decomposable sheet,
A solution application step for applying a solution containing a water-soluble binder and carboxymethylated cellulose nanofibers to the outer surface of the base paper sheet;
A drying step of drying the sheet provided with the solution;
A drug application step of applying an aqueous drug containing a crosslinking agent that crosslinks the water-soluble binder to the dried sheet;
Including
The concentration of the solution applied in the solution application step is 3.0% or more, and the mixing ratio of the water-soluble binder and the carboxymethylated cellulose nanofiber in the solution is a ratio of 9: 1 to 1: 1. It is characterized by being.

The invention according to claim 4
A method for producing a water-decomposable sheet according to claim 3,
The concentration of the solution applied in the solution application step is 3.5% or more.

  According to the present invention, it is possible to improve the resistance to tearing when rubbed strongly while ensuring water disintegration. Therefore, wiping property can be improved.

It is a top view which shows an example of the toilet cleaner which concerns on this embodiment. (A) is a figure which shows the fiber orientation of the conventional paper, (b) is a figure which shows the fiber orientation of this invention. It is the enlarged view and sectional drawing of the embossed part of a toilet cleaner. It is explanatory drawing which shows an example of the contact area of embossing. It is a flowchart which shows the manufacturing method of the toilet cleaner which concerns on this embodiment. It is a schematic diagram of the toilet cleaner manufacturing equipment (solution application equipment) according to the present embodiment. It is a schematic diagram of the manufacturing equipment (processing equipment) of the toilet cleaner which concerns on this embodiment. It is the schematic which shows an example of a papermaking apparatus. It is a graph which shows evaluation of surface strength. It is a graph which shows evaluation of surface strength. It is a top view which shows another example of the toilet cleaner which concerns on this embodiment. It is a top view which shows another example of the toilet cleaner which concerns on this embodiment. It is an AA partial enlarged view of FIG. (A) is a BB cutting part end elevation of Drawing 13, (b) is a CC cutting section end elevation of Drawing 13.

Hereinafter, a water-decomposable sheet which is an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.
The water-decomposable sheet will be described by taking a toilet cleaner as an example, but the water-decomposable sheet includes wet tissue impregnated with an aqueous chemical for wiping purposes other than the toilet cleaner. In addition, the paper conveyance direction at the time of manufacturing the toilet cleaner will be described as the Y direction (vertical direction), and the direction orthogonal to the conveyance direction will be described as the X direction (lateral direction).

[Description of toilet cleaner]
The toilet cleaner 100 is obtained by plying (stacking) a plurality of (for example, two) base paper sheets, and is impregnated with a predetermined aqueous medicine. The base paper sheet may be composed of a single base paper sheet that is not ply-processed.
The basis weight of the base paper sheet is about 30 to 150 gsm. The basis weight is based on JIS P 8124.

  The base paper sheet of the toilet cleaner 100 is made of a water-degradable fiber assembly so that it can be discarded as it is in the toilet bowl after the toilet is cleaned.

  Although it will not specifically limit as a fiber assembly if it is a fiber assembly which has water disintegration property, Single layer or multiple layers paper or a nonwoven fabric can be used suitably. The raw fiber may be natural fiber or synthetic fiber, and these may be mixed. Suitable raw material fibers include cellulose fibers such as wood pulp, non-wood pulp, rayon and cotton, biodegradable fibers made of polylactic acid, and the like. In addition, polyethylene fibers, polypropylene fibers, polyvinyl alcohol fibers, polyester fibers, polyacrylonitrile fibers, synthetic pulp, glass wool and the like can be used in combination with these fibers as a main component.

In particular, it is preferable that the fiber aggregate includes at least pulp, and the pulp used as a raw material is preferably a mixture of hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) at an appropriate ratio.
More preferably, the blending ratio of the hardwood bleached kraft pulp exceeds 50% by weight, that is, the blending ratio of the softwood bleached kraft pulp to the hardwood bleached kraft pulp is less than 1/1. By increasing the compounding ratio of hardwood bleached kraft pulp to softwood bleached kraft pulp, gaps between fibers are reduced and moisture transpiration is suppressed, so that the difficulty of drying can be improved.
Moreover, you may be comprised by the sheet | seat which consists of a pulverized pulp, and the sheet | seat which covered the pulverized pulp with the hydrolytic paper, or was pinched | interposed.

  In addition, a water-soluble binder for enhancing paper strength is applied to the base paper sheet of the toilet cleaner 100. Examples of water-soluble binders include carboxymethylcellulose, polyvinyl alcohol, starch or derivatives thereof, hydroxypropylcellulose, sodium alginate, tant gum, guar gum, xanthan gum, gum arabic, carrageenan, galactomannan, gelatin, casein, albumin, pull plan, polyethylene oxide, bis Examples thereof include binder components such as course, polyvinyl ethyl ether, polyacrylic acid soda, polymethacrylic acid soda, polyacrylamide, hydroxylated derivatives of polyacrylic acid, and polyvinylpyrrolidone / vinylpyrrolidone vinyl acetate copolymer.

In particular, it is preferable to use a water-soluble binder having a carboxyl group from the viewpoint of good water decomposability and the ability to express wet strength by a crosslinking reaction.
The water-soluble binder having a carboxyl group is an anionic water-soluble binder that easily forms a carboxylate in water. Examples thereof include polysaccharide derivatives, synthetic polymers, and natural products.

  Examples of the polysaccharide derivative include a salt of carboxymethyl cellulose, carboxyethyl cellulose or a salt thereof, carboxymethylated denven or a salt thereof, and an alkali metal salt of carboxymethyl cellulose (CMC) is particularly preferable.

Regarding CMC, the degree of etherification is desirably 0.6 to 2.0, particularly 0.9 to 1.8, and more preferably 1.0 to 1.5. This is because water disintegration and wet paper strength are very good.
Moreover, it is preferable to use a CMC that is water-swellable. This demonstrates the function of tying the fibers that make up the sheet while remaining unswelled by crosslinking with specific metal ions that are crosslinkers in aqueous chemicals, providing strength as a wiping sheet that can withstand cleaning and wiping operations. It is because it can express.
In the case of the toilet cleaner 100 of this embodiment, CMC is given as a water-soluble binder.

  Examples of the synthetic polymer include a salt of an unsaturated carboxylic acid polymer or copolymer, a salt of a copolymer of an unsaturated carboxylic acid and a monomer copolymerizable with the unsaturated carboxylic acid, and the like. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic anhydride, maleic acid, and fumaric acid. Examples of monomers that can be copolymerized with these include esters of these unsaturated carboxylic acids, vinyl acetate, ethylene, acrylamide, and vinyl ether. Particularly preferred synthetic polymers are those using acrylic acid or methacrylic acid as the unsaturated carboxylic acid. Specifically, polyacrylic acid, polymethacrylic acid, acrylic acid-methacrylic acid copolymer salt, acrylic acid or methacrylic acid. Examples thereof include a salt of a copolymer of an acid and an alkyl acrylate or an alkyl methacrylate. Examples of natural products include sodium alginate, xanthan gum, gellan gum, tarragant gum, pectin and the like.

Carboxymethylated cellulose nanofiber (hereinafter referred to as CNF) is added to the water-soluble binder (CMC in the case of the toilet cleaner 100 of the present embodiment).
The mixing ratio of CMC and carboxymethylated CNF is preferably 9: 1 to 1: 1. That is, it is preferable that carboxymethylated CNF is contained in the water-soluble binder solution in an amount of 10% by weight to 50% by weight. This is because such a blending ratio can effectively improve the surface strength of the toilet cleaner 100 without increasing the amount of CMC.

  Here, CNF refers to fine cellulose fibers obtained by defibrating pulp fibers, and generally refers to cellulose fibers including cellulose fine fibers having a nano width (1 nm or more, 1000 nm or less). The average fiber width is preferably a fiber of 100 nm or less. The average fiber width is calculated using, for example, a certain number average, median, mode diameter (mode), and the like.

  Examples of pulp fibers that can be used for CNF production include chemical pulps such as hardwood pulp (LBKP) and softwood pulp (NBKP), bleached thermomechanical pulp (BTMP), stone ground pulp (SGP), and pressure stone. Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), Thermo Grand Pulp (TGP), Grand Pulp (GP), Thermo Mechanical Pulp (TMP), Chemi Thermo Mechanical Pulp (CTMP), Refiner Mechanical From mechanical pulp such as pulp (RMP), tea waste paper, craft envelope waste paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, corrugated waste paper, Kami white waste paper, Kent waste paper, counterfeit waste paper, old paper waste paper, and used paper waste Waste paper pulp manufactured, deinked waste paper pulp Such as management and deinking pulp (DIP), and the like. These may be used singly or may be used in combination of plural kinds as long as the effects of the present invention are not impaired.

The carboxymethylated CNF of this embodiment can be obtained by defibrating the pulp fiber that has been subjected to carboxymethylation treatment.
By performing carboxymethylation treatment on CNF, it becomes possible for CNF itself to take a metal ion (preferably divalent) and a crosslinked structure in the same manner as CMC. Strength development is greatly improved. By using CNF and CMC in combination, better strength development can be imparted to the hydrolytic paper.

  The following method can be mentioned as an example of carboxymethylation. Carboxymethylation is not limited to the following method, and can be performed by a conventionally known method. Moreover, it is good also as using a commercial item.

  First, a pulp fiber as a raw material, a solvent such as water and / or lower alcohol, and a mercerizing agent such as sodium hydroxide or potassium hydroxide are mixed to form a mercerization. After the mercerization, for example, monochloroacetic acid, A carboxymethylating agent such as sodium monochloroacetate is added to the reaction system to carry out the etherification reaction.

  In addition, examples of the defibrating treatment include mechanical methods such as a high-pressure homogenizer method, a microfluidizer method, a grinder grinding method, a bead mill freeze pulverizing method, and an ultrasonic defibrating method, but are not limited to these methods. Absent. Moreover, nanofibrosis is accelerated | stimulated by combined use, such as TEMPO oxidation treatment and phosphoric acid esterification treatment acid treatment.

Moreover, the density | concentration of the water-soluble binder solution used for manufacture of the toilet cleaner 100 of this embodiment is 3.0% or more and 4.0% or less, Preferably, it is 3.5% or more and 4.0% or less. More preferably, it is 3.8% or more and 4.0% or less. The water-soluble binder solution of each concentration is applied to the base paper sheet in an application amount corresponding to the concentration, and the total amount of CMC / CNF adhering to the base paper sheet after the application ends is constant.
By setting the concentration of the water-soluble binder solution to 3.0% or more, the surface strength of the toilet cleaner 100 can be effectively improved, and as the concentration increases to 3.5% and 3.8%, More effective. Moreover, handling becomes easy on the operation by making the density | concentration 4.0% or less.

  Such toilet cleaner 100 is in a state in which the content of CMC / CNF gradually increases from the inside to the outside in the thickness direction of the base paper sheet. As a result, the toilet cleaner 100 can be made difficult to break even if the edge of the toilet bowl is rubbed more strongly than a conventional product uniformly impregnated with the same amount of water-soluble binder.

The toilet cleaner 100 according to the present embodiment performs a wear resistance test using a Gakushin type friction fastness tester using a PP band as a school pendulum three times each in the MD direction and the CD direction, each three times. The average of the measured values is calculated so that each average value is 50 times or more.
The above-mentioned abrasion resistance test is performed by folding the toilet cleaner 100 in three, rubbing the measurement part with a Gakushin type friction fastness tester, and measuring the number of times when damage such as fluffing or tearing is visually confirmed on the paper surface. To do.
In the above wear resistance test, a PP band with a mesh pattern on the surface is assumed assuming that the toilet cleaner is actually used, that is, the edge of the toilet bowl is rough due to dirt. It is used as As a result, an environmental test can be performed assuming that the toilet cleaner is actually used, and a highly reliable evaluation can be made as to whether or not the toilet cleaner can withstand the actual use. In the above-mentioned abrasion resistance test, it is a condition that the toilet cleaner can withstand 40 times or more as a standard that it can withstand during actual use.

Moreover, although it does not specifically limit about the ratio (vertical / horizontal) of the fiber orientation of the toilet cleaner 100 in length and width, it is preferable that it is 0.8-2.0, and is 0.8-1.2. It is more preferable.
In the paper making process, which is a paper manufacturing process, fibers are spread on the wire of the paper machine and flow in the transport direction. Therefore, in general, the paper is lined with many fibers in the machine direction of the paper machine. (For example, vertical: horizontal = 2.3: 1, etc., see FIG. 2A). Therefore, the fiber density in the lateral direction is thin and the fiber is easy to tear. That is, it is easy to tear depending on the direction of wiping. Therefore, in the present embodiment, as shown in FIG. 2B, the vertical and horizontal fiber orientation ratio of the toilet cleaner 100 is set to 0.8 to 2.0, preferably 0.8 to 1.2. It is possible to provide a toilet cleaner 100 that is hard to tear when wiped from any direction. The ratio of the vertical and horizontal fiber orientations can be determined by the ratio of the wet strength in the MD and CD directions.

  In addition, the toilet cleaner 100 of the present embodiment is impregnated with a predetermined aqueous drug containing a crosslinking agent that crosslinks with a water-soluble binder. Specifically, in addition to the crosslinking agent, an aqueous cleaning agent, a fragrance, and an antiseptic agent. Further, a predetermined aqueous medicine containing an auxiliary agent such as a disinfectant and an organic solvent is impregnated. The aqueous drug is impregnated in an amount of 100 to 500% by weight, preferably 150 to 300% by weight, based on the weight of the base paper sheet that is the base material of the toilet cleaner 100.

  As the crosslinking agent, boric acid, various metal ions, and the like can be used, but when CMC is used as a water-soluble binder, it is preferable to use a polyvalent metal ion. In particular, the use of one or more polyvalent metal ions selected from the group consisting of alkaline earth metals, manganese, zinc, cobalt, and nickel allows the fibers to be sufficiently bonded to withstand use. It is preferable from the standpoint that strength is developed and water disintegration is sufficient. Of these metal ions, it is particularly preferable to use ions of calcium, strontium, barium, zinc, cobalt, and nickel.

  As the aqueous detergent, for example, a surfactant or a lower or higher (aliphatic) alcohol can be used.

  As a fragrance | flavor, 1 type or several types can be suitably selected and used from oily fragrance | flavors, such as orange oil other than an aqueous | water-based fragrance, for example.

  As the preservative, for example, parabens such as methyl paraben, ethyl paraben, propyl paraben and the like can be used. As a disinfectant, for example, benzalkonium chloride, chlorhexidine gluconate, popidone iodine, ethanol, benzilium cetyl oxide, triclosan, chlorxylenol, isopropylmethylphenol and the like can be used. As the organic solvent, polyhydric alcohols such as glycol (divalent), glycerin (trivalent), and sorbitol (tetravalent) can be used.

  In addition, the above-mentioned auxiliary agent for the component of the aqueous drug can be appropriately selected, and if necessary, a component that performs another function may be included in the aqueous drug.

  As described above, according to the present invention, a water-soluble binder and cellulose nanofiber are blended into a base paper sheet, and the base paper sheet is impregnated with an aqueous drug containing a cross-linking agent that crosslinks with the water-soluble binder. The wet tensile strength can be improved as compared with the case where an aqueous drug containing a crosslinking agent that crosslinks with a water-soluble binder is impregnated.

  Further, the surface of the toilet cleaner 100 may be a raw paper sheet, but is preferably embossed. In the case of the toilet cleaner 100, for example, two types of embosses EM11 and EM12 are embossed as shown in FIG. It is given by processing.

  The shape, number, area ratio, and the like of the emboss are arbitrary, but in the case of the toilet cleaner 100, the emboss EM11 is arranged to be a rhombus lattice, whereby the emboss EM11 is arranged in a square lattice or a rectangular lattice. The unevenness of wiping can be reduced as compared with the case where it is. Further, the embossing EM12 is disposed between the embossing EM11.

As shown in FIG. 3A, the embossed EM11 has a bulged portion PR21 having a curved shape.
Moreover, as shown in FIG.3 (b), the embossing EM12 has the planar shape in the bulging part PR22.

And since the embossing EM12 is arrange | positioned between embossing EM11, when the bulging part PR21 of embossing EM11 and the bulging part PR22 of EM12 adjoin and adjoin, they are connected as shown in FIG.3 (c). The embossed EM21 is formed.
Moreover, the case where the bulging part PR21 of the embossing EM11 and the bulging part PR22 of the embossing EM12 are only close to each other and may not be continuous may be used.

  Since the two types of embosses EM11 and EM12 formed in this way can increase the contact area with the object to be cleaned and the like, the hardness of the toilet cleaner 100 is reduced and the wiping performance is improved.

  That is, by forming the embossed EM11 whose bulged portion PR21 is a curved surface and the embossed EM12 whose bulged portion PR22 is a flat surface on the entire sheet surface of the toilet cleaner 100, the toilet cleaner 100 is powered during wiping work. When each emboss is deformed, the contact area is increased for the first time. Therefore, the contact area is increased, and the flexibility is improved due to the deformation of each emboss.

  For example, as shown in FIG. 4A, in the case of a single embossed EM11, the contact area CN31 generated by the deformation of the embossed EM11 due to the force applied to the toilet cleaner 100 during the wiping operation is discrete in the vicinity of the embossed EM11. Will occur. On the other hand, when two types of embossing EM11 and EM12 are combined, as shown in FIG.4 (b), the embossing EM11 and EM12 which deform | transform and generate | occur | produce by the force added to the toilet cleaner 100 at the time of wiping work It can be seen that the area SN32 increases as compared with the contact area CN31 of FIG.

  Moreover, the two types of embossing EM11 and EM12 can similarly obtain the effect of normal embossing, and can improve the texture, absorbability, bulkiness, and the like of the toilet cleaner. Furthermore, the continuous embossing EM21 can also obtain the effect of the appearance by giving embossing similarly to normal embossing.

  Further, the toilet cleaner 100 is folded into two at the center in the Y direction by being folded. Then, it is stored in a folded plastic case, packaging film, etc. in a folded state, and is expanded and used as needed during use. Note that the method of folding the toilet cleaner 100 is not limited to two, and may be, for example, four or eight.

[Manufacturing method of toilet cleaner]
Next, a method for manufacturing a toilet cleaner will be described. FIG. 5 is a flowchart showing a method for manufacturing a toilet cleaner. FIG. 6 is a schematic diagram of a solution application facility for applying a water-soluble binder solution to a toilet cleaner base paper sheet (papermaking sheet). FIG. 7 is a schematic diagram of processing equipment for processing a base paper sheet to which a water-soluble binder solution has been applied by the solution application equipment shown in FIG.

  In the toilet cleaner manufacturing method, as shown in FIG. 5, first, a paper making process (S1) is performed in which a paper as a base paper is made by a paper machine (not shown).

  Next, as shown in FIG. 5 and FIG. 6, in the solution application facility, continuous dry base paper 1 </ b> A fed out from a plurality of (for example, two) primary raw rolls 1, 1 each wound up the base paper that has been made. A ply processing step (S2) for plying 1A to make a ply continuous sheet 1B, a solution application step (S3) for applying a water-soluble binder solution to the ply continuous sheet 1B to make a continuous sheet 1C, and a continuous sheet 1C A drying step (S4) for drying and a slit / winding step (S5) for slitting and winding the dried continuous water-decomposable sheet 1D are performed. The number of primary rolls can be changed as long as there are two or more. However, in the following description, an example of using two primary rolls will be described.

Next, as shown in FIGS. 5 and 7, in the processing facility, the continuous water-decomposable sheet 1 </ b> D fed from the secondary raw roll 11 wound in the slit / winding step (S <b> 5) is embossed. An embossing process (S6) and a finishing process (S7) for finishing the embossed sheet 1E that has been embossed are performed.
Hereinafter, details of each step will be described in detail.

[Paper making process]
First, the paper making process (S1) according to the present embodiment will be described. In the papermaking step (S1) of the present invention, for example, a papermaking raw material is made by a known wet papermaking technique to form a base paper sheet. That is, after making the papermaking raw material into a wet paper state, it is dried by a dryer or the like to form a base paper sheet such as thin paper or crepe paper.
In addition to the pulp and the flocculant, papermaking chemicals such as a wet paper strength agent, an adhesive, and a release agent may be appropriately used for the base paper sheet.

Moreover, in embodiment of this invention, although a water-soluble binder solution is provided in the solution provision process of the solution provision equipment mentioned later, you may make it provide a water-soluble binder solution in the step of a papermaking process.
When a water-soluble binder solution is applied even in the papermaking process, the strength of the entire water-decomposable sheet can be increased, and by applying a water-soluble binder solution in the subsequent solution application process, the surface of the water-decomposable sheet can be obtained. The strength can be further increased.

  As a method for applying a water-soluble binder solution in a papermaking process, for example, a water-soluble binder and a fixing agent for pulp fibers of the water-soluble binder are added to a dispersion containing pulp as a papermaking raw material, and this is used as a raw material. A method for wet papermaking is known (Japanese Patent Laid-Open No. 3-193996). That is, it is a method of internally adding a water-soluble binder. Alternatively, a sheet made from a pulp-containing dispersion may be wet-papered, press dehydrated or semi-dried, and then a water-soluble binder may be spray-dried or coated and dried to produce a fiber sheet containing a predetermined amount of the water-soluble binder. Is possible. That is, it is a method of externally adding a water-soluble binder. In this case, a fiber sheet having a lower density and better water disintegration can be obtained by using a pre-drying system such as a hot-air passing dryer than performing press dewatering. Furthermore, instead of the above-mentioned wet papermaking method, it is also possible to produce a fiber sheet by drying fiber pulp dry without using water, forming a web, spraying a water-soluble binder, and then drying. . This is the so-called airlaid manufacturing method.

  FIG. 8 shows a schematic view of an example of a production apparatus preferably used for producing a fiber sheet when a water-soluble binder is used as the binder. The manufacturing apparatus (wet papermaking machine) shown in FIG. 8 includes a former 14, a wire part, a first dry part 17, a spray part, and a second dry part 24.

  The former 14 adjusts the furnish supplied from a preparation device (not shown) to a predetermined concentration and supplies it to the wire part. A preparation device (not shown) includes a device that beats and beats raw materials such as pulp fibers, and an addition device that adds additives such as sizing agents, pigments, paper strength enhancers, bleaching agents, and flocculants to the beaten and beaten raw materials. And a stock made of a raw material having a predetermined concentration according to the characteristics of hydrolyzed paper is prepared as a finished stock. It is also possible to mix a binder with the pulp slurry. The wire part is a wet paper that forms the paper stock supplied from the former as a wet paper. The first dry part 17 dries the wet paper formed in the wire part. The spray part sprays the binder onto the paper dried by the first dry part 17. The 2nd dry part 24 dries the paper which has been sprayed with the binder and is wet.

  The furnish supplied from the former 14 is made in the wire part, and a wet paper is formed on the wire 15. Water is removed from the wet paper by suction by a suction box 16 installed in the wire part, and the wet paper has a predetermined moisture content. Next, the wet paper is introduced into the first dry part 17 and dried. The first dry part 17 is composed of a through air dryer (hereinafter referred to as TAD). The TAD includes a rotating drum 18 having a breathable peripheral surface, and a hood 19 that covers the rotating drum 18 almost airtightly. In TAD, air heated to a predetermined temperature is supplied into the hood 19. The heated air flows from the outside of the rotating drum 18 toward the inside. The wet paper web is conveyed in a state of being held on the peripheral surface of the rotary drum 18 rotating in the direction of the arrow in FIG. While being transported in the TAD, the heated paper penetrates the wet paper in the thickness direction, whereby the wet paper is dried to become paper.

  The paper obtained in the first dry part 17 is sprayed with an aqueous solution containing a binder (water-soluble binder solution) in the spray part. The spray part is a position between the first and second dry parts 17 and 24. Both dry parts 17 and 24 are connected via a conveyor.

  The conveyor includes an upper conveyor belt 20 and a lower conveyor belt 21 that rotate in the directions indicated by the arrows. The conveyor 20 is configured to convey paper to the second dry part 24 while being dried by the TAD of the first dry part 17 and sandwiching the paper between the belts 20 and 21. A vacuum roll 22 is disposed at the folded end on the downstream side of the upper conveyor belt 20. The vacuum roll 22 adsorbs paper on the back surface of the upper conveyor belt 20 and conveys the upper conveyor belt 20 under the adsorbed state.

  As shown in FIG. 8, the spray part includes a spray nozzle 23. The spray nozzle 23 is disposed below the second dry part 24 and so as to face the vacuum roll 22. The spray nozzle 23 sprays a spray liquid containing a binder toward the vacuum roll 22 and adds (externally adds) the spray liquid to paper.

  After the binder is supplied in the spray part, the paper is conveyed to the second dry part 24. The second dry part 24 is composed of a Yankee dryer. The paper that has been sprayed with the spray liquid and is in a wet state is conveyed while being held on the peripheral surface of the rotary drum 25 of the Yankee dryer installed in the hood 26. The paper is dried while being held by the rotary drum 25 and conveyed.

  In addition, the position where the binder is supplied in the spray part may be a position between the first and second dry parts 17 and 24. For example, the position above the upper conveyor belt 20 (the first and second dry parts shown in FIG. 8). You may make it spray a binder from the arrow position between 17 and 24). Further, the binder may be sprayed from above (the arrow position on the right side of the second dry part 24 shown in FIG. 8) on the paper after being dried by the second dry part 24. In addition, the direction in which the binder is sprayed between the first and second dry parts 17 and 24 and after the second dry part 24 is not limited to the upper direction, and may be from the lower side or from the upper and lower sides.

  In the present embodiment, in the paper making process, adjustment is performed such that the ratio of vertical and horizontal fiber orientations (vertical / horizontal) of the base paper sheet is 0.8 to 2.0, preferably 0.8 to 1.2. The fiber orientation can be adjusted, for example, by adjusting the angle at which the papermaking raw material is supplied to the wire part in a paper machine. The angle at which the papermaking raw material is supplied can be determined, for example, by adjusting the slice opening degree of the head box. Or it is good also as adjusting fiber orientation by giving a vibration in the direction orthogonal to the conveyance direction (running direction) of a paper machine.

[Ply processing process]
Next, the ply processing step (S2) of this embodiment will be described. In the ply processing step (S2), as shown in FIG. 6, the continuous dry base papers 1A and 1A continuously fed from the raw roll 1 are ply processed along the continuous direction to form a ply continuous sheet 1B. It is supplied to the mating unit 2. The overlapping portion 2 is composed of a pair of rolls, and plies each continuous dry base paper 1A, 1A to form a ply-processed ply continuous sheet 1B. In addition, when the continuous dry base papers 1A and 1A are overlapped, the continuous dry base papers 1A and 1A may be lightly fastened with pin embossing (contact embossing) so that they are not easily displaced.

[Solution application process]
Next, the solution application step (S3) of this embodiment will be described. In the solution application step (S3), as shown in FIG. 6, both outer surfaces of the ply continuous sheet (paper making sheet) 1B (the surfaces where the continuous dry base papers 1A and 1A do not face each other when the continuous dry base papers 1A and 1A are plyed). ) By spraying the water-soluble binder solution with the two-fluid spray nozzles 3 and 3 to produce a continuous sheet 1C.

  The water-soluble binder solution contains carboxymethyl cellulose (CMC) as a water-soluble binder. In addition, carboxymethylated CNF is added to the water-soluble binder solution. The blending ratio of CMC and carboxymethylated CNF is preferably 9: 1 to 1: 1.

  In addition, as the spraying method of the water-soluble binder solution, the above-mentioned water-soluble binder solution may be sprayed on one outer surface of the ply continuous sheet 1B. Further, the above-described primary raw rolls 1 and 1 are fed from the two-fluid type spray nozzle to the outer surface (the surface where the sheets do not face each other) of at least one of the continuous dry base papers 1A and 1A fed from the primary raw rolls 1 and 1 respectively. You may make it produce | generate the sheet | seat equivalent to the above-mentioned continuous sheet 1C by spraying a water-soluble binder solution, and immediately plying the said continuous dry base paper 1A, 1A.

The two-fluid spray nozzle 3 is a spray nozzle that mixes and sprays compressed air and liquid divided into two systems, compared to a one-fluid spray nozzle that sprays compressed liquid alone, The liquid can be sprayed finely and uniformly.
In the present embodiment, the nozzle diameter of the spray nozzle 3 is set to 0.09 gal / min or less. Moreover, as spray conditions of this embodiment, the density | concentration of water-soluble binder solution; 3.0-4.0%, output temperature; 50-70 degreeC, liquid pressure; 2 Mpa or more, air pressure; 0.05-0. It is preferable to be 2MPs.

In this way, by spraying the water-soluble binder solution on the outer surface of the ply continuous sheet 1B, the toilet cleaner is in a state where the contents of CMC and carboxymethylated CNF gradually increase from the inside toward the outside in the thickness direction. Therefore, it is possible to improve the surface strength while ensuring water disintegration, and it is possible to manufacture a toilet cleaner that is less likely to be damaged even when rubbed strongly.
In addition, the inside and the outside in the thickness direction, when applied to both sides, the inside in the thickness direction is the inside and the outside is the outside. Moreover, when apply | coating to one side, let the non-application surface of a water-soluble binder solution be an inner side, and let an application surface be an outer side.

[Drying process]
Next, the drying step (S4) of this embodiment will be described. In the drying step (S4), as shown in FIG. 6, in the drying facility 4, the insoluble liquid in the water-soluble binder solution of the continuous sheet 1C is evaporated, and the active ingredient, particularly CMC, is applied to the fibers. Let it settle.
Here, since the amount of the water-soluble binder solution that permeates decreases from the outside in the thickness direction of the continuous sheet 1C toward the inside, the fixing amount of the CMC decreases as it goes in the thickness direction. Become. Therefore, when the aqueous drug is impregnated in the finishing step (S7) to be described later, the cross-linking reaction is less likely to occur toward the inner side in the thickness direction, and since there are many voids, the aqueous drug is confined inside the sheet. It can be. Thereby, the toilet cleaner obtained can be made hard to dry. In addition, a large amount of CNF is present near the outer side in the thickness direction of the continuous sheet 1C, and many CMC cross-linking reactions occur near the outer side in the thickness direction of the continuous sheet 1C. It can be.
As the drying equipment 4, a hooded dryer equipment that blows hot air on the continuous sheet 1C to dry it can be used. In order to make the sheets more closely contact each other, a press roll or a turn roll may be installed, and the continuous sheet 1C may be passed through the press roll or the turn roll before the drying step (S4).

  Moreover, you may use the installation by infrared irradiation as said drying installation. In this case, a plurality of infrared irradiation units are arranged in parallel in the conveying direction of the continuous sheet 1C, and drying is performed by irradiating the continuous sheet 1C to be conveyed with infrared rays. Since moisture is generated by infrared rays and dried, uniform drying is possible as compared with a dryer using hot air, and wrinkles can be prevented from occurring in the subsequent slit / winding process.

[Slit and winding process]
Next, the slit / winding step (S5) of this embodiment will be described. In the slit / winding step (S5), in order to use the ply-processed continuous water-decomposable sheet 1D with an off-line processing machine, it is dried in the drying step (S4) and the CMC is fixed. The illustrated continuous water-decomposable sheet 1D is slit to a predetermined width by the slitter 5 while adjusting the tension, and wound by the winder facility 6. The winding speed is appropriately determined in consideration of the ply processing step (S2), the solution application step (S3), and the drying step (S4). Note that if it is too early, the sheet will break, and if it is too late, wrinkles will occur.
In the slit / winding step (S5), the continuous water-decomposable sheet 1D subjected to the ply process is pressure-bonded, whereby the continuous water-decomposable sheet 1D is more integrated and becomes a sheet corresponding to one sheet.

[Embossing process]
Next, the embossing process (S6) of this embodiment will be described. In the embossing step (S6), as shown in FIG. 7, the embossing roll 12 has an embossing process that forms a predetermined shape on the entire surface of the continuous water-decomposable sheet 1D fed from the secondary raw roll 11 by the embossing roll 12. Applied. This embossing is performed for the purpose of improving the strength, bulkiness, wiping property and the like of the sheet, as well as the design.

[Finishing process]
Next, the finishing process (S7) of this embodiment will be described. In the finishing process (S7), as shown in FIG. 7, in the finishing equipment 13, the embossed sheet 1E is cut, the cut sheets are folded, and the aqueous chemical ( (Including aqueous detergent, fragrance, preservative, disinfectant, paper strength enhancer, organic solvent, etc.) and packaging of each sheet impregnated with the aqueous agent in a series of flow.
A toilet cleaner is manufactured through the above steps.

  Next, the results of evaluating the surface strength of Examples and Comparative Examples of the present invention will be described.

  First, the blending ratio of CMC and carboxymethylated CNF or CNF (not carboxymethylated) is the following [Example 1] to [Example 3], [Comparative Example 1] to [Comparative Example 6]. A prepared aqueous solution (water-soluble binder solution) was prepared.

[Example 1]
Mixing ratio of CMC and carboxymethylated CNF; 1: 1
[Example 2]
Mixing ratio of CMC and carboxymethylated CNF; 7: 3
[Example 3]
Mixing ratio of CMC and carboxymethylated CNF; 9: 1
[Comparative Example 1]
Mixing ratio of CMC and CNF; 1: 1
(Here, non-carboxymethylated CNF was used.)
[Comparative Example 2]
Mixing ratio of CMC and CNF; 7: 3
(Here, non-carboxymethylated CNF was used.)
[Comparative Example 3]
Mixing ratio of CMC and CNF; 9: 1
(Here, non-carboxymethylated CNF was used.)
[Comparative Example 4]
Mixing ratio of CMC and carboxymethylated CNF; 0:10
[Comparative Example 5]
Mixing ratio of CMC and carboxymethylated CNF; 10: 0
[Comparative Example 6]
Mixing ratio of CMC and CNF; 10: 0
(Here, non-carboxymethylated CNF was used.)

In addition, the carboxymethylated CNF used in Examples 1 to 3 and Comparative Example 4 is BiNFi-s (TMa-100) manufactured by Sugino Machine Co., Ltd.
Moreover, CNF used in Comparative Examples 1-3 and Comparative Example 6 was obtained by performing fibrillation without subjecting NBKP to carboxymethylation treatment.
Moreover, CMC used by Examples 1-3 and Comparative Examples 1-3, 5 is CMC1330 (Daicel).

Next, in a water-soluble binder coating facility, a base paper (pulp blending; NBKP: LBKP = 40: 60) weighing 45 gsm in a dry state is made into two plies, and then each adjusted aqueous solution is sprayed on the outer surface of each sheet. Applied.
At this time, the concentration of the aqueous solution was 3.0%, 3.3%, 3.5%, 3.8%, and 4.0%. Further, the coating amount on the sheet was adjusted according to the concentration of the aqueous solution so that the total amount of CMC and carboxymethylated CNF (or CNF) adhering on each sheet after spray coating was constant. Specifically, the coating amount of the aqueous solution on the sheet is 30% when the wet coating amount is 40 gsm, 3.3% when the wet coating amount is 36.4 gsm, and 3.5% when the wet coating amount is 34.3 gsm and 3.8%. The wet coating amount was 31.6 gsm and the wet coating amount was 30 gsm at 4.0%. The dry coating amount is 1.2 gsm.

  Thereafter, the substrate is passed through a hot air dryer (temperature 180 ° C.), dried until the moisture content becomes about 8%, and a raw sheet for processing a base paper sheet is prepared while slitting to a predetermined width. The sampled base paper sheet was uniformly impregnated with a drug solution (aqueous drug) to 200% by weight of the sheet with a syringe to obtain samples corresponding to Examples 1 to 3 and Comparative Examples 1 to 6.

[Evaluation of surface strength]
<Test method>
Samples corresponding to Examples 1 to 3 and Comparative Examples 1 to 6 were cut in the MD direction and the CD direction at 75 mm in width and 240 mm in length without peeling off the ply so that both end regions in the width direction overlap. Fold it up, rub the measured part with a Gakushin type friction fastness tester, and measure the number of times when damage such as fluffing and tearing is visually confirmed on the paper surface. This measurement is performed three times each in the MD direction and the CD direction, and the average of the measured values for each three times is calculated.
The test conditions with the Gakushin type friction fastness tester are as follows.
・ Gakushin friction fastness tester: Tester Sangyo Co., Ltd., part number AB301
・ Friction element: Shape 20mm × R50mm
Load 200gf (including white cotton cloth stopper and arm)
Load per unit area 50 gf / cm ² (load 200 gf / contact area 4.0
cm ² )
PP band (Sekisui Jushi Corporation part number 19K (width 15mm)
× Length 60mm)) Be careful not to create gaps or wrinkles on one sheet.
Secure to the friction element with a tie stop.
・ Sample stage: Shape R200mm
Stroke 120mm
Round trip speed 30 cps
・ Sample: width 25mm (without peeling off the ply, fold 75mm in width)
× Length 240mm (sample stage side)
・ Test procedure: (1) Mount the sample on the sample base so as not to loosen.
(2) Gently lower the friction element onto the sample table.
(3) Start test by pressing start SW.
・ Judgment method: The state of the sample is confirmed by swaying, and fluffing or tearing is visually observed on the paper.
The number of times when such damage was confirmed was measured.

  In the above test, assuming a scene where the toilet cleaner is actually used, that is, assuming that the edge of the toilet bowl is rough due to contamination, a PP band with a mesh pattern on the surface is used as a school pendulum. ing. As a result, an environmental test can be performed assuming that the toilet cleaner is actually used, and a highly reliable evaluation can be made as to whether or not the toilet cleaner can withstand the actual use.

<Evaluation>
FIG. 9 is a graph showing the results of the test in the MD direction. FIG. 10 is a graph showing the results of the test in the CD direction.
Although the numerical value used as a standard of whether a toilet cleaner can endure at the time of actual use is 40 times, as shown in FIG. 9, FIG. In the range of not less than% and not more than 4.0%, it can be seen that the numerical value is 50 times or more and has high strength.
Further, Examples 1 to 3 show that the numerical value increases as the concentration of the aqueous solution increases, and the strength increases as the concentration of the aqueous solution increases.
Moreover, it turns out that intensity | strength becomes high when Examples 1-3 and Comparative Examples 1-3 use carboxymethylated CNF compared with the case where CNF which is not carboxymethylated is used. This is presumably because the strength of CNF itself was increased by subjecting CNF to carboxymethylation treatment.
Moreover, in Comparative Examples 4-6, it is less than the numerical value used as this standard, and it turns out that it cannot endure at the time of actual use.

As described above, according to this embodiment, a water-soluble binder solution having a blending ratio of CMC and carboxymethylated CNF of 9: 1 to 1: 1 is used, and the concentration is 3.0% or more, 4 By setting the content to 0.0% or less, the surface strength can be improved while maintaining water disintegration.
Therefore, the surface strength can be improved without increasing the coating amount of CMC contained in the water-soluble binder solution.

As mentioned above, although this invention was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.
For example, in the description of the embodiment of the present invention, a toilet cleaner is exemplified as a water-decomposable sheet. However, the present invention is not limited to this. It can be applied to articles that need to be discarded with a large amount of water.

  In the description of the embodiment of the present invention, the embossed EM11 in which the bulging part PR21 has a curved shape and the embossed EM12 in which the bulging part PR22 has a flat shape are illustrated. However, it is not necessarily limited to this shape, and any shape of embossing is applicable.

  For example, in the description of the embodiment of the present invention, all the embosses EM11 and EM12 are convex in the front side of the drawing in FIG. 1, but the embossments EM11 and EM12 convex in the front side of the drawing and the front side in the drawing. Alternatively, the concave embosses EM11 and EM12 may be alternately arranged.

  Specifically, as shown in FIG. 11, the embosses EM11 and EM12 (solid line portions) convex in the front direction of FIG. 11 and the embossments EM11 and EM12 (broken line portions) concave in the front direction of FIG. By disposing in, it is possible to increase the surface strength of the water-decomposable sheet by embossing and to provide a water-decomposable sheet having high wiping performance on both sides of the toilet cleaner 101.

Moreover, the modification which changed only the embossing pattern of the toilet cleaner is shown in FIGS.
12-14, the recessed part e2 is the shape which reversed the convex part e1. The convex portions e1 and the concave portions e2 are alternately arranged as an example, and this row forms an emboss pattern in which the rows are arranged in multiple rows and the convex portions e1 and the concave portions e2 in adjacent rows are shifted from each other by a half pitch. . As described above, the convex portions e1 and the concave portions e2 are alternately formed both in the vertical direction and in the horizontal direction, so that the wiping property of dirt is improved compared to the embossed pattern in which the convex portions and the concave portions are arranged in a line. Can be made. In addition, the shape of the convex part e1 and the recessed part e2 is not specifically limited, Circular, an ellipse, a polygon etc. are used. It is good also as what combined each shape.

  In the description of the embodiment of the present invention, the water-soluble binder solution is applied by a spray method. However, the doctor is applied to the continuous dry base paper 1A continuously fed from the primary raw roll 1. Chamber system (transfer equipment with two plate rolls paired with one backup roll, anilox rolls paired with each plate roll, and a doctor chamber for applying a binder solution to each anilox roll) Or / and 3-roll system (two plate rolls paired with one backup roll, anilox roll paired with each plate roll, and a dip for applying a binder solution to each anilox roll Roll and a transfer facility comprising a pan for applying a binder solution to the dip roll). Nda solution may be granted. In other words, in the solution application step, the water-soluble binder solution is transferred to the corresponding base paper from a printing machine provided corresponding to at least one of the front and back surfaces of the water-decomposable sheet. Also good.

100, 101 Toilet cleaner 1 Primary raw roll 1A Continuous dry base paper 1B Ply continuous sheet 1C Continuous sheet 1D Continuous water-decomposable sheet 1E Embossed sheet 2 Superposition part 3 Spray nozzle 4 First drying equipment 5 Slitter 6 Winder equipment 11 2 Next fabric roll 12 Embossing roll 13 Finishing processing equipment 14 Former 15 Wire 16 Suction box 17 First dry part 18 Rotary drum 19 Hood 20 Upper conveyor belt 21 Lower conveyor belt 22 Vacuum roll 23 Spray nozzle 24 Second dry part 25 Rotary drum 26 Hoods EM11, EM12, EM21 Embossed PR21, PR22 Swelling part HT21, HT22 Swelling part height CN31, SN32 Contact area e1 Convex part e2 Concave part

Claims (4)

A water-degradable sheet obtained by impregnating a base paper sheet with an aqueous drug,
The base paper sheet has a basis weight of 30 to 150 gsm, contains a water-soluble binder and carboxymethylated cellulose nanofibers,
The water-decomposable sheet, wherein the aqueous drug contains a cross-linking agent that cross-links with the water-soluble binder. The base paper sheet is
A wear resistance test using a Gakushin type friction fastness tester using a PP band as a Gakuden pendulum was performed three times each in the MD direction and the CD direction, and the average of the three measured values was calculated. The water-decomposable sheet according to claim 1, wherein the value is 50 times or more. A solution application step for applying a solution containing a water-soluble binder and carboxymethylated cellulose nanofibers to the outer surface of the base paper sheet;
A drying step of drying the sheet provided with the solution;
A drug application step of applying an aqueous drug containing a crosslinking agent that crosslinks the water-soluble binder to the dried sheet;
Including
The concentration of the solution applied in the solution application step is 3.0% or more, and the mixing ratio of the water-soluble binder and the carboxymethylated cellulose nanofiber in the solution is a ratio of 9: 1 to 1: 1. A method for producing a water-decomposable sheet, characterized in that   The method for producing a water-decomposable sheet according to claim 3, wherein the concentration of the solution applied in the solution application step is 3.5% or more.

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