JP6275671B2 - Water-decomposable sheet and method for producing water-degradable sheet - Google Patents

Description

  The present invention relates to a water-decomposable sheet and a method for producing a water-decomposable sheet.

Conventionally, woven cloth cloths that are used repeatedly have been used for cleaning toilets. Instead, disposable wet sheets made of paper have been used in recent years. And this type of wet sheet is preferably provided in a state of being impregnated with a cleaning agent, and can be processed by flowing into a toilet after use.
In such wet sheets, 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 disintegrability that does not clog piping etc. when flowing into a toilet or the like. However, as one technique for effectively achieving these, it is known to use a hydrolytic paper to which a water-soluble binder containing carboxymethylcellulose (CMC) is added as the base paper (for example, Patent Document 1). reference).

JP 2005-076141 A

  By the way, for example, when a wet sheet is used for cleaning a toilet, the conventional wet sheet may be broken if the edge of the toilet is rubbed strongly. Therefore, it has been a problem to improve the resistance to tearing when rubbed strongly while ensuring water disintegration.

  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 having improved water-disintegrability and improved resistance to tearing when strongly rubbed.

In order to solve the above-mentioned problem, the invention described in claim 1
A water-decomposable sheet comprising a substantially water-dispersible multi-ply base paper sheet containing pulp and a water-soluble binder,
The water-soluble binder is applied to both surfaces of the water-decomposable sheet,
The smoothness of the coated surface coated with the water-soluble binder of the base paper sheet is higher than the smoothness of the non-coated surface where the water-soluble binder is not coated,
The coated surface is a smooth surface smoothed in a paper making process .

The invention according to claim 2 is the invention according to claim 1,
The coating surface is a dryer surface of a dryer part in a paper making process.

The invention according to claim 3 is the invention according to claim 1 or 2,
The content of the water-soluble binder is increased as it goes to the front and back surfaces.

Invention of Claim 4 is a manufacturing method of the water-decomposable sheet as described in any one of Claims 1-3,
A paper making process of drying a wet paper to make a plurality of base papers,
A ply processing step of plying the plurality of base papers;
A solution application step of applying a binder solution containing the water-soluble binder to the ply processed sheet in the ply processing step;
Including
In the ply process, the ply process is performed with the smooth surface smoothed in the paper making process as an outer surface.

The invention according to claim 5 is the invention according to claim 4,
In the solution application step, the binder solution is sprayed to a corresponding outer surface from a spray nozzle provided corresponding to both outer surfaces of the ply-processed sheet.

The invention according to claim 6 is the invention according to claim 4 or 5,
A drying step of drying the sheet to which the binder solution has been applied in the solution application step;
An embossing process for embossing the sheet dried in the drying process;
Is further included.

The invention according to claim 7 is the invention according to any one of claims 4 to 6,
The basis weight of each of the plurality of base papers not containing the water-soluble binder is 15 to 75 gsm,
The basis weight of the plurality of ply base paper sheets is 30 to 150 gsm.

  According to the present invention, since the smoothness of the outer surface of the water-decomposable sheet is high, the water-soluble binder tends to stay on the outer surface and the surface strength is increased, and tearing when rubbed strongly while ensuring water-decomposability. A water-decomposable sheet with improved bitterness can be provided.

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 which shows an example of the manufacturing equipment (solution provision equipment) of the toilet cleaner which concerns on this embodiment. It is a schematic diagram which shows an example of the manufacturing equipment (processing equipment) 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 a top view which shows another example of the toilet cleaner which concerns on this embodiment. FIG. 10 is an AA partial enlarged view of FIG. 9. (A) is a BB cutting part end elevation of Drawing 10, and (b) is a CC cutting part end elevation of Drawing 10. It is the schematic which shows an example of a papermaking apparatus.

  Hereinafter, a water-decomposable sheet that is an embodiment of the present invention and a method for producing the water-decomposable sheet will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

In the water-decomposable sheet according to the present invention, the water-decomposable sheet will be described using the toilet cleaner 100 as an example, but the water-decomposable sheet according to the present invention is wet tissue impregnated with a chemical solution for wiping purposes other than the toilet cleaner. Is also included. Further, the paper conveyance direction at the time of manufacturing the toilet cleaner 100 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).

[Composition of toilet cleaner 100]
First, the configuration of the toilet cleaner 100 will be described.
The toilet cleaner 100 is obtained by plying (stacking) a plurality of (for example, two) base paper sheets, and is impregnated with a predetermined chemical solution. Moreover, as shown in FIG. 1, two types of embossing EM11 and EM12 are given to the whole sheet | seat surface of the toilet cleaner 100 by embossing. The contact area between the two embossing EM11 and such cleaning object caused by EM12 is, 100 mm ² per ^is preferably 15 mm 2 ～30Mm ² about.

  For example, by arranging the embossed EM11 to be a rhombus lattice, it is possible to reduce wiping unevenness compared to the case where the embossed EM11 is disposed in a square lattice or a rectangular lattice. Further, the embossing EM12 is disposed between the embossing EM11.

  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.

  In addition, the base paper sheet of the toilet cleaner 100 of the present embodiment is composed of a water-decomposable fiber assembly so that the toilet paper can be discarded as it is in a toilet pool after cleaning the toilet.

  As the fiber assembly, fibers obtained by mixing hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) are used. As a suitable raw material fiber, the component 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. Can be given. 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. Further, in order to improve the surface strength of the base paper sheet that is the base material of the toilet cleaner 100, a solution containing carboxymethyl cellulose (CMC) is applied to the base paper sheet from the front and back as a binder solution for enhancing paper strength. The toilet cleaner 100 is in a state in which the content of CMC increases from the center in the thickness direction toward the front and back surfaces. As a result, the toilet cleaner 100 is less likely to be broken even if the edge of the toilet bowl is rubbed more strongly than a conventional product that is uniformly impregnated with a water-soluble binder. Moreover, the front surface and the back surface (application surface) of the base paper sheet (ply continuous sheet 1B) to which the binder solution is applied are both the dryer surface of the dryer part in the paper making process described later. In other words, the smoothness of the coated surface of the base paper sheet coated with CMC is higher than the smoothness of the non-coated surface where CMC is not coated.

Further, the toilet cleaner 100 preferably has a ratio of vertical and horizontal fiber orientation (vertical / horizontal) of 0.8 to 2.0, and more preferably 1.0.
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 this embodiment, as shown in FIG.
By setting the vertical and horizontal fiber orientation ratio to 0.8 to 2.0, preferably 1.0, it is possible to provide the toilet cleaner 100 that is not easily torn 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 chemical solution (aqueous drug). Specifically, in addition to an aqueous cleaning agent, a fragrance, an antiseptic, a disinfectant, a paper strength enhancer, A predetermined chemical solution containing an auxiliary agent such as an organic solvent is impregnated. The chemical solution is preferably impregnated in an amount of 150 to 300% by weight with respect to the weight of the base paper sheet that is the base material of the toilet cleaner 100.

  As the chemical solution, an appropriate one can be used. For example, as the aqueous cleaning agent, 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 out of oil-based fragrance | flavors, such as orange oil other than an aqueous | water-based fragrance | flavor. 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 paper strength enhancer (crosslinking agent), boric acid, various metal ions, 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 chemical solution can be appropriately selected, and a component that performs other functions may be included in the chemical solution as necessary.

  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 CN32 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.

[Manufacturing method of toilet cleaner 100]
Next, a method for manufacturing the toilet cleaner 100 will be described.
FIG. 5 is a flowchart showing a method for manufacturing the toilet cleaner 100. FIG. 6 is a schematic diagram of a solution application facility for applying a binder solution to the base paper sheet of the toilet cleaner 100. FIG. 7 is a schematic diagram of processing equipment for processing a base paper sheet to which a binder solution has been applied by the solution application equipment shown in FIG.

  In the manufacturing method of the toilet cleaner 100, as shown in FIG. 5, first, a paper making process (S1) for making a paper as a base paper with a paper machine (not shown) is performed.

  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 form a ply continuous sheet 1B, a solution application step (S3) for applying a binder solution to the ply continuous sheet 1B to form a continuous sheet 1C, and drying the continuous sheet 1C A drying process (S4) and a slit / winding process (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. Details of each process will be described later.

[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.
The method for manufacturing the toilet cleaner 100 according to this embodiment includes a creping process in which the wet paper is creped (wet creping) before the wet paper is dried by a dryer or the like in the paper making process (S1). ing. When creping is performed in this creping process, it is desirable that the crepe rate is 10 to 15%. In the creping process, only wet creping is performed to crepe the wet paper before drying the wet paper, but the wet paper that has been wet creped is dried. Thereafter, dry creping may be further performed by creping the dried paper. However, the crepe rate of the dry creping process at this time is set lower than that of the wet creping process.
As a raw material of the base paper sheet, for example, known virgin pulp, waste paper pulp and the like can be used, and at least pulp fibers are included. As the pulp used as the raw material, a blend of LBKP and NBKP in an appropriate ratio is particularly suitable. In addition, rayon fiber, synthetic fiber, etc. may contain as fibers other than a pulp fiber.
The base paper sheet of the present invention contains an anionic acrylamide polymer (hereinafter referred to as “anionic PAM”) as a flocculant. An anionic PAM is a polymer obtained by copolymerizing an acrylamide monomer and an anionic monomer.
Examples of the acrylamide monomer include acrylamide alone or a mixture of acrylamide and the following nonionic monomer copolymerizable with acrylamide. Nonionic monomers copolymerizable with acrylamide include methacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, N-isopropylacrylamide, N-hydroxyethylacrylamide, diacetone. Examples include acrylamide, acryloylmorpholine, N-acryloylpyrrolidine, N-acryloylpiperidine, N-vinylrolidone, N-vinylformamide, and N-vinylacetamide. These may be used alone or in combination of two or more.
Examples of the anionic monomer include acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid, itaconic acid, maleic acid, fumaric acid, and neutralized salts thereof.
A monomer such as styrene, acrylonitrile, (meth) acrylic acid ester, or the like may be blended as long as the water solubility of the anionic PAM is not impaired.
The addition amount of the anionic PAM is preferably about 10 to 1000 ppm. By making paper using such an anionic flocculant having the same charge as pulp, the aggregation of the base paper sheet can be reduced, and the water disintegrability can be improved by capillary action.
In addition to the above-described pulp and 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 binder solution is provided in the solution provision process of the solution provision equipment mentioned later, you may make it provide a binder solution in the step of a papermaking process.
When a binder solution is applied even in the paper making process, the strength of the entire water-decomposable sheet can be increased, and by further applying a binder solution in the solution-applying process in the subsequent process, the surface strength of the water-decomposable sheet is further increased. Can be raised.

  As a method for applying the binder solution in the papermaking process, for example, a water-soluble binder and a fixing agent to the pulp fiber of the water-soluble binder are added to a dispersion liquid containing pulp as a papermaking raw material, and this is used as a raw material. A paper making method 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. 12 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. 12 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 transported while being held on the peripheral surface of the rotating 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 (binder solution) containing a binder 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. 12, 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 dryer part 24. The second dryer 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. 12). 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. 12) 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 so that the ratio of vertical and horizontal fiber orientations (vertical / horizontal) of the base paper sheet is 0.8 to 2.0, preferably 1.0. 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.

[Continuous dry base paper]
As physical properties of the continuous dry base paper 1A, the basis weight is preferably about 15 to 75 gsm. Moreover, the basis weight of the ply-processed sheet containing the water-soluble binder (continuous water-decomposable sheet 1D) is about 30 to 150 gsm. The basis weight is based on JIS P 8124.
The continuous dry base paper 1A becomes a ply-processed hydrolyzed paper through a ply processing step (S2), a solution application step (S3), a drying step (S4), and a slit / winding step (S5), which will be described later. The toilet cleaner 100 is processed through an embossing process (S6) and a finishing process (S7).

[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. Here, each continuous dry base paper 1A, 1A is plyed so that the dryer surface (smooth surface) of the dryer part in the paper making process is the outer surface.
The overlapping portion 2 is composed of a pair of rolls, and plies each continuous base paper 1A, 1A to form a ply continuous sheet 1B subjected to ply processing. 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.

[Binder solution]
Next, the binder solution will be described. The binder solution contains carboxymethyl cellulose (CMC) as a water-soluble binder. The concentration of carboxymethylcellulose in the binder solution is 1 to 30% by weight, preferably 1% by weight or more and less than 4% by weight.

  On the other hand, the degree of etherification of CMC is desirably 0.6 to 2.0, particularly 0.9 to 1.8, and more preferably 1.0 to 1.5. The expression of water disintegration and wet paper strength is very good.

  Moreover, CMC can use a water-swellable thing. This demonstrates the function of tying together the fibers constituting the sheet while remaining unswelled by crosslinking of specific metal ions in the chemical solution, and can exhibit strength as a wiping sheet that can withstand cleaning and wiping operations.

  Ingredients other than carboxymethylcellulose in the binder solution include polyvinyl alcohol, starch or derivatives thereof, hydroxypropylcellulose, sodium alginate, tolton gum, guar gum, xanthan gum, gum arabic, carrageenan, galactomannan, gelatin, casein, albumin, pull plan, poly Examples thereof include binder components such as ethylene oxide, viscose, polyvinyl ethyl ether, polyacrylic acid soda, polymethacrylic acid soda, polyacrylamide, hydroxylated derivatives of polyacrylic acid, and polyvinylpyrrolidone / vinylpyrrolidone vinyl acetate copolymer.

It is preferable to use a water-soluble binder having a carboxyl group from the viewpoint of good water decomposability and a point at which wet strength can be expressed 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 is particularly preferable.

  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.

[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, two fluids are formed on both outer surfaces of the ply continuous sheet 1B (the surfaces on which the continuous dry base papers 1A and 1A do not face each other when the continuous dry base papers 1A and 1A are plyed). The above-mentioned binder solution is sprayed by the spray nozzles 3 and 3 of the system or the one-fluid system to generate the continuous sheet 1C.
The ply continuous sheet 1B immediately after the ply processing in the ply processing step is merely overlapped with the continuous dry base papers 1A and 1A. Therefore, in the solution applying step, the binder solution is sprayed from both sides of the ply continuous sheet 1B. , 3 is substantially the same as the case where the binder solution is applied in a state where the continuous dry base papers 1A and 1A are separated, the binder solution penetrates in the thickness direction, and the sheets adhere to each other during conveyance. It penetrates further during crimping in the slit and winding process.
In addition, as a spraying method of a binder solution, you may make it spray the above-mentioned binder solution on the 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 binder solution and carrying out the ply process of the said continuous dry base paper 1A, 1A immediately after.

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.
When a two-fluid spray nozzle is used in the present embodiment, a binder solution (viscosity 400 to 1200 MPa.s) is applied to each outer surface of the ply-processed ply continuous sheet 1B with a high pressure (injection pressure of 1.5 MPa or more). Since it is applied, it is easy to impregnate the binder solution in the thickness direction of the sheet.
On the other hand, when a one-fluid spray nozzle is used in the present embodiment, a binder solution (viscosity 400 to 1200 MPa.s) is applied to the outer surface of each ply-processed ply continuous sheet 1B at an injection pressure of 1.5 MPa or less. Thus, the binder solution is easily impregnated in the thickness direction of the sheet, and the binder solution is easily applied uniformly on the sheet surface.
In this way, by spraying the binder solution onto the outer surface of the ply continuous sheet 1B, the toilet cleaner 100 is centered in the thickness direction (when applied on both sides) or non-coated with the binder solution (when applied on one side). Since the content of the water-soluble binder increases as it goes from the surface to the application surface of the binder solution, the surface strength can be improved while ensuring water disintegration, and the toilet cleaner 100 is less likely to be damaged even when rubbed strongly. Can be manufactured.

[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 equipment 4, the insoluble liquid in the binder solution of the continuous sheet 1C is evaporated to fix the active ingredient, particularly CMC, to the fibers. .
Here, since the amount of the binder solution that permeates decreases from the outer surface of the continuous sheet 1C toward the inside in the thickness direction, the fixing amount of CMC decreases toward the inside in the thickness direction. Therefore, when the chemical solution is impregnated in the finishing step (S7) described later, the cross-linking reaction hardly occurs as it goes inward in the thickness direction, and since there are many voids, the chemical solution is confined inside the sheet. be able to. Thereby, the toilet cleaner 100 obtained can be made hard to dry.
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 chemicals are applied to the folded sheets. Impregnation and packaging of each sheet impregnated with the chemical solution are performed in a series of flows. Here, when CMC is used as the water-soluble binder, the cross-linking agent contained in the chemical solution is preferably 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.
The toilet cleaner 100 is manufactured through the above steps.

In the manufacturing method of the toilet cleaner 100 described above,
A ply processing step of plying a plurality of base papers not containing a water-soluble binder;
A solution application step of applying a binder solution to the ply-processed sheet;
A drying step of drying the sheet provided with the binder solution;
A winding step of slitting and winding the sheet dried in the drying step to a predetermined width;
Including
In the solution application step, the binder solution is sprayed to the corresponding outer surface from spray nozzles provided corresponding to both outer surfaces of the ply-processed sheet.
In the ply processing step, a plurality of base papers that do not contain a water-soluble binder may be ply-processed, and a plurality of base papers that contain a water-soluble binder may be ply-processed.

  Next, it manufactures with the manufacturing method of the toilet cleaner of this embodiment, ie, in a ply processing process, each so that the outer surface (front surface and back surface) of the ply continuous sheet 1B may become the dryer surface (smooth surface) of the dryer part in a papermaking process. The toilet cleaner (Example) manufactured by plying the continuous dry base papers 1A and 1A, and the outer surface (front surface and back surface) of the continuous ply sheet 1B in the ply processing step is the dryer surface of the dryer part in the paper making step ( The toilet cleaner (comparative example) manufactured by plying each of the continuous dry base papers 1A and 1A so as to be the opposite surface (non-smooth surface) to the smooth surface) was evaluated for damage when rubbed strongly. The results and the evaluation results regarding the amount of paper dust generated will be described using Tables 1 and 2. Note that whether the outer surface of the toilet cleaner is a smooth surface or a non-smooth surface can be determined by looking at a cross section of the toilet cleaner.

<Conditions for implementation>
Example Material of base paper: 100% pulp
Pulp blending; NBKP: LBKP = 40: 60
Weighing: 45 g / m ²
Number of plies; 2 plies
Ply mode: The dryer surface (smooth surface) of the dryer part in the paper making process
Ply to be the outer surface (front and back) of the sheet
Water-soluble binder and its content; CMC 0.6 g / m ² (spray coating)
Chemical component: Surfactant, glycol ether, disinfectant, fragrance, water, etc.
Chemical solution impregnation rate: 200%
Embossing; Comparison example Base material: Pulp 100%
Pulp blending; NBKP: LBKP = 40: 60
Weighing: about 45 g / m ²
Number of plies: 2
Ply mode; the dryer surface (smooth surface) of the dryer part in the paper making process
The opposite surface (non-smooth surface) becomes the outer surface (front surface and back surface) of the sheet.
Ply as
Water-soluble binder and its content: CMC 0.6 g / m ² (spray coating)
Chemical component: Surfactant, glycol ether, disinfectant, fragrance, water, etc.
Chemical solution impregnation rate: 200%
Embossing: Yes

<Test method>
Cut the test piece (toilet cleaner) into a width of 75 mm x length of 240 mm without peeling off the ply, fold it in three so that both end regions in the width direction overlap, and rub the measured part with a Gakushin type friction fastness tester Then, the number of times at which damage such as fluffing or tearing is visually confirmed on the paper surface is measured. 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
・ Test piece (toilet cleaner): width 25mm (ply is not peeled and 75mm width is folded in three)
× Length 240mm (sample stage side)
Test procedure: (1) Mount the test piece on the sample stage so as not to loosen.
(2) Gently lower the friction element onto the sample table.
(3) Start test by pressing start SW.
・ Judgment method: Check the condition of the test piece by swaying, and visually check for fluffing and tearing.
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 method for paper dust generation>
Each of the above examples and comparative examples was rubbed up and down 10 times on a black tile (the paper dust is white so that it is easy to see visually), and the paper dust on the tile was visually confirmed. The evaluation was evaluated as “◎” when there was no paper dust, “◯” when paper was slightly present, “Δ” when paper dust was present, and “×” when paper dust was high. Moreover, this evaluation was implemented 5 times in each of the Examples and Comparative Examples.

  As shown in the test results shown in Table 1, in the example, the MD direction is “40 times” and the CD direction is “55 times”, and in the comparative example, the MD direction is “20 times” and the CD direction is “40 times”. Thus, it was found that the example had a stronger surface strength than the comparative example in both the MD direction and the CD direction.

  Moreover, as the evaluation of the paper dust generation amount shown in Table 2, the evaluation of the examples was “◯” for all five times, and it was found that the paper dust was hardly generated. On the other hand, the evaluation of the comparative example was “Δ” for 3 out of 5 times and “x” for the remaining 2 times, and it was found that paper dust was likely to be generated.

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.
In describing the embodiment of the present invention, the embossed EM11 in which the bulging part PR21 has a curved shape and the embossing EM12 in which the bulging part PR22 has a flat shape are illustrated. It is not necessarily limited to this shape, for example, the bulging part of embossing EM11 and embossing EM12 may be a planar shape from which height differs. Further, for example, the bulging portion of the emboss EM 11 may be a flat shape, and the bulging portion of the emboss EM 12 may be a curved shape.

  In other words, there are two types of embossing (first embossing and second embossing) in which the shape of the bulging part is not the same shape, and the second embossing is arranged around the first embossing. If it exists, the shape of the bulging portion of each emboss may be any shape.

  In the description of the embodiment of the present invention, the embossed EM12 having a flat bulge is disposed between the embossed EM11 having a curved bulge, but the embossed EM11 intersects each other. Also good.

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

  For example, as shown in FIG. 8, embosses EM11 and EM12 (solid line portions) convex in the front direction of FIG. 8 and embossments EM11 and EM12 (broken line portions) concave in the front direction of FIG. Thus, 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 surfaces of the toilet cleaner 100.

In the description of the embodiment of the present invention, the bulging portion PR21 of the emboss EM11 and the bulging portion PR22 of the EM12 are formed as a continuous embossing EM21 by closely adhering to each other. The bulging portion PR21 and the bulging portion PR22 of the EM 12 may be close to each other but not closely attached.

  In the description of the embodiment of the present invention, the shape of the emboss EM 11 is exemplified as a circular shape or an elliptical shape, but the emboss shape may be any shape such as a square or a polygon.

  Moreover, it is preferable that height HT21 and HT22 of the bulging part of embossing EM11 and EM12 in FIG. 3 are 0.40 mm-0.75 mm, for example. The height of the bulging portion of the emboss can be measured by measuring the surface in 3D with a Keyence digital microscope.

  For example, if the height is less than 0.40 mm, the friction at the time of wiping becomes strong and difficult to wipe, and if the height exceeds 0.75 mm, the shapes of the embosses EM11 and EM12 are liable to break during packaging. It looks bad.

  Moreover, the embossing pattern of the toilet cleaner is not limited to the above-described pattern. 9 is a plan view of the toilet cleaner 101 in which only the embossing pattern of the toilet cleaner 100 is changed, FIG. 10 is an enlarged view of a portion AA in FIG. 9, and FIG. 11A is a BB cut portion in FIG. FIG. 11B is an end view of the CC cut part in FIG.

  9-11, 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 binder solution is applied by a spray method. However, the doctor chamber method (for the continuous dry base paper 1A continuously fed from the primary original roll 1 ( Transfer equipment comprising two printing plate rolls paired with one backup roll, an anilox roll paired with each printing plate roll, and a doctor chamber for applying a chemical to each anilox roll), and / or 3 roll system (two printing rolls paired with one backup roll, anilox roll paired with each printing roll, dip roll for applying chemicals to each anilox roll, and dip roll The binder solution may be applied by a transfer facility equipped with a pan for applying a chemical solution to . That is, in the method for producing a water-decomposable sheet obtained by plying a plurality of base papers (continuous dry base paper 1A), out of a plurality of base papers that do not contain a water-soluble binder, A solution application step of applying (transferring) a binder solution to at least one of the surfaces; a ply processing step of plying the plurality of base papers; a drying step of drying the ply-processed sheet; and the drying step A winding step for slitting and winding the sheet dried in a predetermined width, and the solution application step corresponds to at least one of the surfaces of the base paper as the front surface and the back surface of the water-decomposable sheet The binder solution is transferred from the provided printing machine to the corresponding base paper.
In the solution application step, among the plurality of base papers that do not contain a water-soluble binder, the binder solution is applied to at least one surface of the base paper as the front and back surfaces of the water-decomposable sheet, and the water-soluble binder is water-soluble. You may make it provide a binder solution with respect to at least any one surface of the base paper used as the surface of a water-decomposable sheet and a back surface among several base paper containing a binder.

In mere roll transfer, in order to apply a desired amount of chemical solution, a very high concentration chemical solution is required, and such a chemical solution has a high viscosity and cannot be uniformly transferred by roll transfer. Further, if the concentration is lowered in order to lower the viscosity, the desired applied amount cannot be obtained as described above. As described above, since it is extremely difficult to apply a chemical to the dried base paper, a doctor chamber method and / or a three-roll method is adopted.
By adopting a doctor chamber method or / and a three-roll method in which a pair of printing plate rolls is provided for one backup roll, a sufficient amount of chemical solution is applied to each printing plate roll at least in the total amount. Can be applied to the dried base paper. Further, since there is only one backup roll, it can be applied extremely uniformly. This is because the tension between the first printing roll and the next printing roll is extremely stable and constant because there is only one backup roll. However, the chemical solution can be applied to the continuous base paper very uniformly. In addition, since the interval between the two printing plate rolls is shortened, even after the chemical solution is applied on the first printing plate roll and then applied on the next printing plate roll, uniform transfer can be performed without uneven application. It is. Such an effect cannot be obtained simply by making the backup roll and the plate roll into a pair of two stages.

More preferably, the chemical solution is applied by the doctor chamber method because the chemical solution can be transferred more uniformly and stably in the width direction than the three-roll method.
Furthermore, it has the drying process which dries the continuous paper to which the chemical | medical solution was provided. This drying process is preferably indirect drying without direct contact with the continuous paper, particularly by infrared irradiation. In the case of indirect drying, generation of wrinkles is suppressed. In particular, if it is caused by infrared irradiation, drying of the various portions of the paper surface occurs uniformly, so that generation of wrinkles and distortion during drying can be effectively prevented.
The doctor chamber method will be described in detail below as an example.

In this doctor chamber type transfer equipment, one plate roll is provided for one backup roll.
The coating processing speed when applying the binder solution is 30 to 100 m / min, and more preferably 50 to 80 m / min. If it is less than 30 m / min, the crepe stretches before being dried, and there is a problem that it is difficult to process in a subsequent process. On the other hand, when the amount exceeds 100 m / min, a sufficient transfer amount cannot be obtained, or variation in wet strength and water disintegration occurs due to variation in the coating amount in the width direction.

The diameter of the backup roll is suitably 250 to 420 mm. When the diameter is less than 250 mm, the contact area between the printing plate roll and the backup roll is reduced, and stable coating cannot be performed. Even if the diameter exceeds 420 mm, there is no problem in manufacturing, but it is not preferable because the equipment cost is excessive.

The printing plate roll is provided with an anilox roll for delivering a binder solution thereto, and a doctor chamber for delivering the binder solution to the anilox roll for application thereto is provided. For the doctor chamber, a snake pump that delivers the binder solution to the doctor chamber is installed on both the feed and return to feed the anilox roll solution pan. High binder solution transfer is possible.

The continuous dry base paper 1A fed out from the primary raw roll 1 is wound around a backup roll through an appropriate guide roll, and given appropriate tension and surface stability.
Then, the binder solution is roll-transferred by the printing plate roll to the continuous dry base paper 1A wound around the backup roll.
Here, the printing plate roll is a solid roll with no concave grooves, and a binder solution is applied to the entire continuous dry base paper 1A as in solid printing. The seamless roll used as the printing plate roll is formed by winding a rubber plate around a sleeve of a type roll, putting it in a kettle, performing overheating welding, and polishing. The rubber plate used as the material can be selected in material, hardness, color and the like according to a predetermined purpose.

On the other hand, the number of lines and the cell capacity of the anilox roll delivering the binder solution to the printing plate roll are 60 to 120 lines / inch and the cell capacity is 40 to 90 ml / m ² depending on the concentration of the binder solution. Is desirable. If the number of lines is less than 60 lines / inch, an excessive binder solution is transferred to the printing plate roll, and as a result, the binder solution may be applied to the continuous dry base paper 1A with unevenness from the printing plate roll. Rise. On the other hand, when the number of lines exceeds 120 lines / inch, it becomes difficult to deliver a sufficient amount of the binder solution to the entire peripheral surface of the printing plate roll. Further, if the cell capacity is less than 40 ml / m ² , it becomes difficult to deliver a sufficient amount of the binder solution to the printing plate roll, and even if the cell capacity exceeds 90 ml / m ² , only the yield is deteriorated. .
Note that the continuous dry base paper 1A to which the binder solution is applied (transferred) as described above targets only the base paper that is the uppermost layer or the lowermost layer when plying. That is, for example, in the case of three-ply processing, the binder solution is not applied (transferred) to the continuous dry base paper 1A serving as the middle layer.

In the doctor chamber method, the binder solution is transferred to the continuous dry base paper 1A, that is, the binder solution is transferred to the continuous dry base paper 1A before the ply processing step. Thereafter, the binder solution may be transferred to the ply continuous ply sheet 1B.
That is, in a method for producing a water-degradable sheet obtained by plying a plurality of base papers (continuous dry base paper 1A), a ply processing step of plying a plurality of base papers not containing a water-soluble binder, and a ply-processed sheet A solution application step for applying (transferring) the binder solution to the sheet, a drying step for drying the sheet provided with the binder solution, and a winding step for slitting and winding the sheet dried in the drying step to a predetermined width. And the solution applying step transfers the binder solution to a corresponding outer surface from a printing machine provided corresponding to the outer surface of at least one of the ply-processed sheets.
In the ply processing step, a plurality of base papers that do not contain a water-soluble binder may be ply-processed, and a plurality of base papers that contain a water-soluble binder may be ply-processed.
Thus, when transferring a binder solution by a doctor chamber system, since a binder solution with high viscosity can be apply | coated, it can suppress that a binder solution osmose | permeates the inside of a sheet | seat. Therefore, CMC can be fixed only on the sheet surface. In addition to the case where the binder solution is transferred by the doctor chamber method, for example, the binder surface may be coated on the sheet surface by a coater for hot melt resin coating. In such a case, it is possible to fix the CMC only on the sheet surface.

In the description of the embodiment of the present invention, the binder solution is applied in the solution application process of the solution application equipment shown in FIG. 6, but the binder solution may be applied in the paper making process. Good.
That is, in the method for producing a water-decomposable sheet obtained by plying a plurality of base papers (continuous dry base paper 1A), the paper making process includes making a plurality of base papers, and the paper making process is performed on wet paper being made. To apply a binder solution.

Specifically, in the paper making process, for example, the wet paper formed by the paper making net is transported on the felt, and the wet paper on the felt is transferred to the Yankee dryer via the touch roll. The wet paper is dried to obtain a base paper in the process of being attached and conveyed, and the binder solution is sprayed from the spray nozzle onto the wet paper immediately after being transferred onto the above-mentioned Yankee dryer.
Thus, when the binder solution is applied even in the paper making process, the strength of the entire water-decomposable sheet obtained can be increased, and the surface of the water-decomposable sheet can be obtained by further applying the binder solution in the subsequent solution applying process. The strength can be further increased.

  In describing the embodiments of the present invention, CMC is used as the water-soluble binder, but polyvinyl alcohol (PVA) may be used.

  In addition, the detailed configuration of the toilet cleaner 1 can be changed as appropriate without departing from the spirit of the present invention.

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 Hood EM11 Embossed EM12 Embossed EM13 Embossed PR21 Swelling part PR22 Swelling part

Claims (7)

A water-decomposable sheet comprising a substantially water-dispersible multi-ply base paper sheet containing pulp and a water-soluble binder,
The water-soluble binder is applied to both surfaces of the water-decomposable sheet,
The smoothness of the coated surface coated with the water-soluble binder of the base paper sheet is higher than the smoothness of the non-coated surface where the water-soluble binder is not coated,
The water-decomposable sheet , wherein the coated surface is a smooth surface smoothed in a papermaking process .   The water-decomposable sheet according to claim 1, wherein the coating surface is a dryer surface of a dryer part in a papermaking process.   The water-decomposable sheet according to claim 1 or 2, wherein the content of the water-soluble binder is increased toward the front surface and the back surface. A method for producing a water-decomposable sheet according to any one of claims 1 to 3,
A paper making process of drying a wet paper to make a plurality of base papers,
A ply processing step of plying the plurality of base papers;
A solution application step of applying a binder solution containing the water-soluble binder to the ply processed sheet in the ply processing step;
Including
In the ply process, the ply process is performed using the smooth surface smoothed in the paper making process as an outer surface.   5. The water-decomposable sheet according to claim 4, wherein, in the solution application step, the binder solution is sprayed to a corresponding outer surface from a spray nozzle provided corresponding to both outer surfaces of the ply-processed sheet. Production method. A drying step of drying the sheet to which the binder solution has been applied in the solution application step;
An embossing process for embossing the sheet dried in the drying process;
The method for producing a water-decomposable sheet according to claim 4, further comprising: The basis weight of each of the plurality of base papers not containing the water-soluble binder is 15 to 75 gsm,
The method for producing a water-decomposable sheet according to any one of claims 4 to 6, wherein the basis weight of the plurality of ply base paper sheets is 30 to 150 gsm.

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