JP2007075523A - Hydrolyzable sanitary paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide hydrolyzable sanitary paper with water absorbency and excellent strike through preventive capability. <P>SOLUTION: The ratio of the strength in the longitudinal direction of an outer layer to the strength in the longitudinal direction of another layer in the multi-layered hydrolyzable sanitary paper is 1:2.1 to 1:7.5, and the ratio of the dry tension strength in the lateral direction to that in the longitudinal direction is 1:2.0 to 1:3.5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water-decomposable sanitary paper such as toilet paper.

Since water-degradable sanitary paper such as toilet paper directly touches the skin, consumers are required to have excellent functionality such as softness, softness, smoothness, and thickness.
In recent years, with the spread of warm water flush toilet seats, further demands have been made on toilet paper. That is, the main purpose of using toilet paper in a warm water flush toilet seat is to wipe off the water remaining on the body surface after washing, so that toilet paper used in the warm water flush toilet seat is particularly required to absorb water. It has become. And in this toilet paper, it is calculated | required that the whole quantity of the water which remained on the body surface is absorbed, and the absorbed water | moisture content penetrates and does not reach a wiping hand side.
Then, toilet paper suitable for a warm water washing toilet seat which can improve a water absorption by using the space which arises by stacking a sheet and can perform a necessary function with one set of sheets is proposed (for example, patent documents). 1).
JP 2002-172072 A

However, in the above invention, the water-degradable sanitary paper is overlaid and the sanitary paper is embossed to increase the surface area, thereby securing water absorption and improving water absorption, but the number of embosses increases. There arises a problem that the softness and smoothness are lowered and the touch becomes worse. In addition, since there is no consideration about the softness and smoothness of the sanitary paper surface, there is a problem that it is difficult for a user who has a disease especially in the excretion part who prefers a warm water washing toilet seat.
Then, the main subject of this invention is providing the water-decomposable sanitary paper which can ensure a water absorption, can aim at prevention of a see-through, and can give a feeling of thickness and a softness | flexibility.

The invention according to claim 1 of the present invention which has solved the above problems
A water-degradable sanitary paper having a multilayer structure having two or more layers,
The ratio of the longitudinal tensile strength according to JIS P 8113 of at least one outer layer to the longitudinal tensile strength according to JIS P 8113 of any other layer is 1: 2.1 to 1: 7.5 The water-degradable sanitary paper is characterized in that the ratio of the transverse direction and the longitudinal direction of the dry tensile strength based on JIS P 8113 as a whole water-degradable sanitary paper is 1: 2.0 to 1: 3.5. .

The invention according to claim 2 is the water-decomposable sanitary paper according to claim 1, wherein each layer has a basis weight of 11 to 22 g / m ² and each layer has a paper thickness of 60 to 200 μm.

In the invention according to claim 3, the water absorption amount of at least one outer layer is 150 to 400 g / m ² , and the water absorption amount of any layer other than the layer is 100 to 300 g / m ^2. 2. The water-decomposable sanitary paper according to 2.

  According to the first aspect of the present invention, the moisture absorbed in the outer layer is quickly trapped inside, and then the moisture can be diffused in a layer having a strength higher than that of the outer layer. It is possible to favorably penetrate the moisture while ensuring appropriateness. As this mechanism, increasing the strength is to promote the beating of the raw pulp in the pre-papermaking stage and to promote the binding between pulp fibers during papermaking. As a result, there are less voids between fibers, making it difficult for moisture to pass. . In other words, reducing the strength means that there are more voids between the fibers and moisture easily passes, so the strength of the outer layer that comes into direct contact with moisture is reduced, and first the moisture is quickly trapped inside. The moisture can be diffused in a layer having a higher strength than the outer layer. The ratio is preferably 1: 2.1 to 1: 7.5. If the ratio is smaller than this lower limit, the absorbed moisture is likely to diffuse inside, but the moisture penetrates in the vertical direction when the moisture is wiped off, and the hand gets wet. There is a fear. If it is larger than the upper limit, the diffusion of moisture does not proceed and the moisture cannot be sufficiently absorbed. For example, in the case of toilet paper, moisture may remain in the excretory part and the vicinity thereof. Further, the ratio of the transverse direction and the longitudinal direction of the dry tensile strength is preferably 1: 2.0 to 1: 3.5 so that the water-decomposable sanitary paper itself does not collapse when wiping off moisture. If it is smaller than this lower limit, the absorbed moisture easily diffuses inside, but the water-decomposable sanitary paper may collapse when wiping off the moisture. If it is larger than the upper limit, the diffusion of moisture does not proceed and it tends to flow backward and return to the outer layer.

Further, as described in claim ² , it is desirable that the structure of the water-decomposable sanitary paper is such that each layer has a basis weight of 11 to 22 g / m ² and each layer has a paper thickness of 60 to 200 μm.

Furthermore, as described in claim 3, the water absorption amount of at least one outer layer is 150 to 400 g / m ² , and the water absorption amount of any layer other than that layer is 100 to 300 g / m ^2. desirable.

  In the invention according to claim 4 of the present invention, the dry tensile strength in the machine direction of at least one outer layer is 100 to 250 cN / 25 mm, and the dry tensile strength in the machine direction of any layer other than that layer is The water-decomposable sanitary paper according to any one of claims 1 to 3, which has a viscosity of 100 to 800 cN / 25 mm.

  According to the fourth aspect of the invention, it is possible to more suitably prevent problems such as tearing during use.

  The invention according to claim 5 is the water-decomposable sanitary paper according to any one of claims 1 to 4, wherein the result of the looseness test defined in JIS P 4501 is 80 seconds or less.

  According to the fifth aspect of the present invention, for example, even when discarded in a flush toilet after use, water is quickly dissolved and clogging of the toilet is prevented.

  In the invention of claim 6, 1 ml of water is dropped on a horizontal and smooth place where water does not permeate, and then spread to 30 mm × 40 mm, and then placed in an oven in a dry condition as defined in JIS L 0208 for 3 minutes. The water-degradable sanitary paper according to any one of claims 1 to 5, wherein a plurality of sanitary papers after being left are stacked, and the number of the sanitary papers into which water permeates into the stacked sanitary papers is 20 or less.

  According to the sixth aspect of the present invention, it is possible to suitably prevent moisture from getting through. Note that the number of sanitary papers in claim 6 is a concept different from “layer” and means 1 ply = 1 sheet. Therefore, for example, a product of a set of two plies may be generally counted as one product, but in claim 6 it is calculated as two.

  The invention according to claim 7 is the water-decomposable sanitary paper according to any one of claims 1 to 6, wherein a softening agent is added to at least one outer layer.

  According to the seventh aspect of the present invention, the softness is particularly excellent, and moisture can be suitably wiped off without damaging the affected part, particularly for a user who has a disease in the excretory part.

  The invention according to claim 8 is the water-degradable sanitary paper according to any one of claims 1 to 7, wherein a transient wet paper strength agent and / or a cationic starch is added to any layer other than the outer layer. It is.

  According to the invention described in claim 8, since the surface strength of at least one of the layers other than the outer layer is increased, the generation of paper dust can be suppressed.

  The invention according to claim 9 is the water-decomposable sanitary paper according to any one of claims 1 to 8, which is laminated and embossed.

  According to invention of Claim 9, while improving a feeling of thickness, a water absorption can be improved by enlarging a surface area.

  According to the water-decomposable sanitary paper of the present invention, it is possible to ensure water absorption, reliably prevent back-through, and give a sense of thickness and flexibility. In addition, it is possible to reduce the generation of paper powder that can be softened, and that is likely to be generated with the softening.

Embodiments of the present invention will be described below with reference to the drawings.
〔Construction〕
The water-decomposable sanitary paper 10 according to the present invention has three or more layers as shown in FIGS. Here, it should be noted that the “layer” in the present invention does not mean a so-called “ply”. That is, the water-decomposable sanitary paper 10 may be a single ply as shown in the illustrated example, for example, a multi-ply paper, but it may be a multi-ply of 2 plies, 3 plies, 4 plies or more, although not shown. May be. At this time, each ply may be composed of a plurality of layers overlapping each other, or may be composed of each layer alone.
As shown in FIG. 1, the water-decomposable sanitary paper 10 according to the present invention is a liquid having a slow permeation rate in which at least one layer other than one outer layer 11, in the illustrated example, the middle layer 21 exerts a weak size effect. It is a permeation suppression layer. Thereby, when the outer layer is a liquid-absorbing layer, penetration of moisture W absorbed (water absorption) into one outer layer 11 (for example, the surface layer) is prevented (extraction to the other outer layer 12 (for example, the back layer)), The problem of being unsanitary due to moisture getting on hands is solved. At this time, as shown in FIG. 2, the middle layers 21 and 21 may be two or more layers, and all of them may be liquid permeation suppression layers. In the present specification, the layers constituting both surfaces of the water-degradable sanitary paper 10 are expressed as outer layers 11 and 12, and all layers sandwiched between the outer layers 11 and 12 are expressed as middle layers 21.

[Raw materials for base paper]
In the water-decomposable sanitary paper according to the present invention, the raw material of the base paper is not particularly limited, and an appropriate raw material can be used. When using pulp fiber as a raw material, examples of the pulp fiber (raw pulp) include wood pulp, non-wood pulp, synthetic pulp, waste paper pulp, and more specifically, groundwood pulp (GP), stone Mechanical pulp (MPC) such as ground pulp (SGP), refiner ground pulp (RGP), pressurized groundwood pulp (PGW), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), bleach chemithermomechanical pulp (BCTMP) ), Chemical mechanical pulp (CGP), semi-chemical pulp (SCP), hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP) and other kraft pulp (KP), soda pulp (AP), sulfite pulp (SP), chemical pulp (CP) such as dissolving pulp (DP) , Synthetic pulp made from nylon, rayon, polyester, polyvinyl alcohol (PVA), deinked pulp (DIP), waste paper pulp such as waist pulp (WP), ground pulp (TP), cotton, flax, hemp, jute , One or several kinds of rag pulp, straw pulp, esparto pulp, bagasse pulp, bamboo pulp, kenaf pulp and other auxiliary pulps such as bast pulp, etc. Can be used.
Raw materials such as pulp fibers are used as a base paper through, for example, a known papermaking process, specifically, a wire part, a press part, a dryer part, a size press, a calendar part, and the like. In this papermaking, for example, suitable chemicals such as a dispersant, caustic soda, aqueous ammonia and other pH adjusters, antifoaming agents, preservatives, fluorescent dyes, mold release agents, water resistance agents, flow modifiers, yield improvers, etc. Can be added.
However, it is preferable that at least one of cellulose, hemicellulose, hydrophilic acetate cellulose, and hydrophilic nonwoven fabric is used as a raw material for the liquid absorption layer.
On the other hand, the liquid permeation suppression layer is preferably made of at least one of a film, a water-repellent nonwoven fabric, and acetate cellulose. However, even when the liquid permeation suppression layer uses pulp fibers as a raw material, it becomes preferable that the sizing agent is contained in an amount of 0.02 to 0.06% in terms of the solid content to the absolute dry mass of the pulp. .05% is more preferable. If the blending amount of the sizing agent is less than 0.02% by mass, it is impossible to sufficiently reduce the back-through of the liquid. On the other hand, when the compounding quantity of a sizing agent exceeds 0.06 mass%, the problem that water repellency becomes too strong will arise.
As the sizing agent, for example, a neutral sizing agent such as alkyl ketene dimer, alkenyl succinic anhydride, and stearic anhydride, an acidic sizing agent such as saponified natural rosin, and reinforced rosin can be used.

[Water absorption time]
The water absorption time of the water-decomposable sanitary paper in the present invention is measured by the following method under the conditions of JIS P8111. First, the sample sheet is placed on the mouth of the cup, and the periphery of the sample is fixed to the mouth of the cup with a rubber band. Next, use a dropper to drop 1 drop (5 μl) of water onto the sample from a height of 1 cm, measure the time from when the drop falls until it is completely sucked into the sample with a stopwatch. Time (second / drop). Here, when it is determined that the light is not reflected when the water droplet is viewed not obliquely but obliquely (at an inclination of 45 degrees with respect to the vertical), it is determined that the water has been completely sucked into the sample.
Based on this, it is preferable that the ratio of the water absorption time when the outer layer and the middle layer are measured independently is from 1:15 to 1: 1.5. On the other hand, when the water absorption time of the outer layer is set to 1, when the water absorption time of the middle layer is more than 15, moisture absorption in the middle layer cannot catch up and the diffusion is mainly, moisture remains on the surface of the middle layer, Since it returns to the outer layer, it is insufficient to ensure water absorption. On the other hand, when the water absorption time of the outer layer is set to 1, if the water absorption time of the middle layer is less than 1.5, the moisture permeates in the vertical direction quickly, and the water penetrates to the other outer layer, so that it penetrates. There is a fear.

[Water absorption]
Water absorption of the outer layer is a liquid-absorbing layer is preferably comprised between 150 and 400 / m ^2. This is because if it is less than 150 g / m ² , moisture remains in the outer layer, which is insufficient to ensure water absorption. On the other hand, if it exceeds 400 g / m ² , it is excellent in securing water absorption, but it is because there is a risk that the moisture may be reversed due to hand pressure during use.
The water absorption amount of the middle layer which is the liquid permeation suppression layer is preferably 100 to 300 g / m ² . This is because if it is less than 150 g / m ² , moisture remains in the outer layer, which is insufficient to ensure water absorption. Further, if it exceeds 300 g / m ² , it is excellent in securing water absorption, but there is a risk that the moisture may be reversed due to hand pressure during use.

[US tsubo]
In the method for measuring the basis weight of JIS P 8124, the basis weight of each layer of the water-decomposable sanitary paper according to the present invention is preferably 11 to 22 g / m ² . This is because if it is less than 11 g / m ² , it is preferable from the viewpoint of improving the softness of the toilet paper, but the strength of the toilet paper cannot be ensured properly. On the other hand, if it exceeds 22 g / m ² , it becomes too hard to use as toilet paper, resulting in poor touch.

[Paper thickness]
The paper thickness of each layer is preferably 60 to 200 μm. This is because when the thickness is less than 60 μm, it is preferable from the viewpoint of improving the softness of the toilet paper, but the strength of the toilet paper cannot be ensured properly. On the other hand, if it exceeds 200 μm, the toilet paper is too hard and has a poor touch, and a feeling of tingling is generated during use.
In addition, as a measuring method of paper thickness, it shall measure using the dial thickness gauge (thickness measuring device) "PEACOCK G type" (made by Ozaki Seisakusho) on the conditions of JISP8111. Specifically, confirm that there is no dust, dust, etc. between the plunger and the measuring table, lower the plunger on the measuring table, move the memory of the dial thickness gauge to adjust the zero point, and then Then, raise the plunger and place the sample (toilet paper) on the test table, slowly lower the plunger and read the gauge at that time. At this time, only the plunger is placed. The paper thickness is an average value obtained by performing measurement 10 times.

〔Tensile strength〕
The tensile strength of the water-degradable sanitary paper according to the present invention is measured based on the tensile test method of JIS P 8113. Examples of the wet paper strength enhancer to be added include polyamide polyamine epichlorohydrin resin, urea formaldehyde resin, and melamine formaldehyde resin.
Further, it is preferable to add a temporary wet paper strength agent and / or a cationic starch to at least one of the layers other than the outer layer, preferably 0.5 to 8.0 kg / ton (pulp ton). It is desirable to add. On the other hand, if it exceeds 8.0 kg / ton (pulp ton), the paper strength is too strong, which becomes a hindrance to water disintegration when discarded in a flush toilet after use. On the other hand, if it is less than 0.5 kg / ton (pulp ton), the surface strength is poor, so that the cellulose fibers protruding from the surface become fluffy, and as a result, paper powder that is a lump of cellulose fibers tends to be generated.

[Water disintegration]
As for the water decomposability of the water decomposable sanitary paper according to the present invention, the result of the test method for ease of loosening defined by JIS P 4501 is preferably 80 seconds or less. This is because if it exceeds 80 seconds, even if it is discarded in a flush toilet after use, the water disintegration is slow and the drain pipe may be clogged.

[Moisture penetration]
The water permeation degree of the water-decomposable thin paper is preferably such that a plurality of thin paper sheets are stacked horizontally, and the number of water permeating into the stacked thin paper sheets is 20 or less.
Here, as a specific method for measuring the moisture penetration degree, for example, three sets (three plies) of toilet paper are set as one set, and these are sequentially stacked to prepare at least 10 sets of stacked samples. Next, 1 ml of water is weighed with a spoid and spread evenly over an area of 30 mm × 40 mm on a horizontal and smooth test table that does not penetrate water. For spreading, a glass piece such as a spoid itself or a preparation used in a microscope can be used, and other glass pieces may be used as long as they can be spread uniformly. Next, prepare a weight, and put the sample stacked on the spread water gently from the top, place the weight almost at the center on the top almost the same time, release the weight after about 1 second, Count the number.
The weight is 650 g, and the bottom has an area of 30 mm × 50 mm. As a placement method, the weight is placed so that the side of 30 mm extends along the side of 30 mm of the spread water, and covers the spread water. The area of 30 mm × 50 mm assumes the area of the paper that comes into contact with the wet excretion part and the periphery of the excretion part after using the warm water washing toilet seat in actual use. Moreover, 650g assumes the force applied when wiping the excretion part after excretion and the excretion part periphery with a toilet paper. The reason why the number of water permeated is 20 or less is that, in practice, the toilet paper is often folded and used so as to be 20 sheets or less. From the viewpoint of preventing the back-through, the number is preferably 15 or less.

[Softness]
The softness (JIS L1096 bending synthesis) of the water-degradable sanitary paper according to the present invention is preferably 1.5 to 3.5 g. This is because if it is less than 1.5 g, it becomes too soft as toilet paper and it is difficult to ensure a sense of thickness. Moreover, when it exceeds 3.5 g, it is because it becomes too hard as a toilet paper and the touch deteriorates.
Here, softness is a resistance value (average value in length and width) when a sanitary thin paper having a width of 10 cm is pushed into a gap having a width of 5.0 mm by a terminal, and means that the smaller the value is, the softer it is. In this specification, softness refers to a value measured by the handle ohm method (JIS L-1096 E method). The softness can be adjusted, for example, by changing the basis weight, the number of layers, the types of fibers and films forming the layers, the fusing process conditions, and the like.

〔Softener〕
In the water-decomposable sanitary paper according to the present invention, it is preferable to add a softening agent to the outer layer. Examples of softeners are surfactant-based softeners, which include anionic surfactants, nonionic surfactants, cationic surfactants and zwitterionic surfactants. It can be appropriately selected and used.
As the anionic surfactant, carboxylate, sulfonate, sulfate ester, phosphate ester, and the like can be used. An alkyl phosphate ester salt is particularly preferable.
Examples of the nonionic surfactant include polyhydric alcohol monofatty acid esters such as sorbitan fatty acid ester, diethylene glycol monostearate, diethylene glycol monooleate, glyceryl monostearate, glyceryl monooleate, propylene glycol monostearate, N- (3 -Oleirosoxy-2-hydroxypropyl) diethanolamine, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbit dense wax, polyoxyethylene sorbitan sesquistearate, polyoxyethylene monooleate, polyoxyethylene monolaurate, polyoxyethylene cetyl Ether, polyoxyethylene lauryl ether and the like can be used.
As the cationic surfactant, a quaternary ammonium salt, an amine salt, an amine, or the like can be used. In addition, as the zwitterionic surfactant, an aliphatic derivative of a secondary or tertiary amine containing carboxy, sulfonate, sulfate, an aliphatic derivative of a heterocyclic secondary or tertiary amine, or the like is used. be able to.
As the zwitterionic surfactant, an aliphatic derivative of a secondary or tertiary amine containing carboxy, sulfonate, sulfate, or an aliphatic derivative of a heterocyclic secondary or tertiary amine may be used. it can.
These softeners may be added internally or externally. In addition, secondary additives such as anionic surfactants, fragrances, colorants, preservatives, and antioxidants can be added to the chemical solution at a ratio of 1% or less.
By adding a softening agent, surface softness and smoothness are expressed, and the touch is improved. In particular, a user who has a disease in the excretory part can wipe off moisture appropriately without damaging the affected part.

[Temporary wet paper strength agent]
Add a temporary wet paper strength agent so that the surface does not become rough or tear at the amount of water at the time of wiping off, but it should be destroyed by a large amount of water at the time of disposal, for example, water flow in a flush toilet Can do. For example, TS-20 (manufactured by Starlight PMC) or the like can be used.
In the water-degradable sanitary paper according to the present embodiment, if it is at least 2 plies and stacked after embossing is applied to each sheet, it becomes possible to improve the thickness feeling and increase the surface area to improve water absorption. Is preferred. More preferably, laminate embossing is desirable.

  The physical properties and the like of the water-decomposable sanitary paper having a three-layer structure according to Examples and Comparative Examples of the present invention were measured. Table 1 shows the evaluation items and results. In addition, each Example and each comparative example are toilet paper of 3 sheets (3 plies), and each ply has a single layer structure.

  As can be seen from Table 1, in Examples 1 to 4, even though water absorption is ensured, the prevention of breakthrough is also achieved. On the other hand, Comparative Examples 1 to 3 are substantially the same as the Examples in terms of water absorption, but are inferior in moisture penetration and do not have the ability to prevent see-through. Furthermore, Examples 1-4 are excellent in softness (softness), and also have sufficient water decomposability and tensile strength (dry and wet). Accordingly, it can be said that the water-decomposable sanitary paper of the present invention has sufficient water absorption, is reliably prevented from falling through, and has softness. The water disintegration value is an average of three times.

  INDUSTRIAL APPLICABILITY The present invention can be used for water-decomposable sanitary paper such as toilet paper and disposable wiping sheets, and water-degradable paper such as toilet cleaning sheets.

It is sectional drawing of the water-decomposable sanitary paper concerning this Embodiment. It is sectional drawing of the other example of the water-decomposable sanitary paper concerning this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Water-decomposable sanitary paper, 11 ... Outer layer (surface layer), 12 ... Outer layer (back layer), 21 ... Inner layer, W ... Moisture.

Claims (9)

A water-degradable sanitary paper having a multilayer structure having two or more layers,
The ratio of the longitudinal tensile strength according to JIS P 8113 of at least one outer layer to the longitudinal tensile strength according to JIS P 8113 of any other layer is 1: 2.1 to 1: 7.5 A water-decomposable sanitary paper, wherein the ratio of the transverse direction and the longitudinal direction of the dry tensile strength based on JIS P 8113 as a whole water-degradable sanitary paper is 1: 2.0 to 1: 3.5. ^2. The water-decomposable sanitary paper according to claim 1, wherein the weight of each layer is 11 to 22 g / m ² and the thickness of each layer is 60 to 200 μm. The water absorption of at least one of the outer layers are 150 and 400 / m ^2, the water absorption amount of any of the layers other than the layer is 100 to 300 g / m ^2, according to claim 1 or 2 water-disintegrable hygiene paper according.   The dry tensile strength in the machine direction of at least one outer layer is 100 to 250 cN / 25 mm, and the dry tensile strength in the machine direction of any layer other than that layer is 100 to 800 cN / 25 mm. The water-decomposable sanitary paper according to any one of 1 to 3.   The water-decomposable sanitary paper according to any one of claims 1 to 4, wherein the result of a looseness test defined in JIS P 4501 is 80 seconds or less.   After dropping 1 ml of water in a horizontal and smooth place where water cannot permeate, spread it to 30 mm x 40 mm, and then put a plurality of sheets of sanitary paper after standing for 3 minutes in an absolutely dry dryer as defined in JIS L 0208 The water-decomposable sanitary paper according to any one of claims 1 to 5, wherein the number of sanitary papers stacked and permeated with water into the stacked sanitary papers is 20 or less.   The water-decomposable sanitary paper according to any one of claims 1 to 6, wherein a softening agent is added to at least one outer layer.   The water-decomposable sanitary paper according to any one of claims 1 to 7, wherein a transient wet paper strength agent and / or a cationic starch is added to any layer other than the outer layer.   The water-decomposable sanitary paper according to any one of claims 1 to 8, which is laminated and embossed.

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