Wet sheet

Abstract

To provide a wet sheet which is excellent in flexibility and strength and which improves hydrolyzability.SOLUTION: A wet sheet comprises an air-laid nonwoven fabric layer 10, and a liquid composition with which the air-laid nonwoven fabric layer 10 is impregnated. The air-laid nonwoven fabric layer 10 contains carboxymethylcellulose at a ratio of 1-10 mass%. The liquid composition contains calcium chloride at a ratio of 1 mass% or more and glycols at a ratio of 20-40 mass%. The air-laid nonwoven fabric layer 10 has a thickness of 0.5 mm or more and a density of 0.2 g / cm3 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wet sheet.

Background Art

[0002] Hydrolyzable articles are used for cleaning areas around water such as toilets and for wiping the body. Patent Document 1 describes a hydrolyzable article in which an aqueous chemical is impregnated in a fiber sheet containing pulp and a binder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Hydrolyzable articles such as those in Patent Document 1 are required to have excellent flexibility and strength, and further improvement in hydrolyzability.

Means for Solving the Problems

[0005] The wet sheet of Aspect 1 is a wet sheet comprising an airlaid nonwoven fabric layer and a liquid composition impregnated in the airlaid nonwoven fabric layer, wherein the airlaid nonwoven fabric layer contains carboxymethyl cellulose in a proportion of 1% by mass or more and 10% by mass or less, the liquid composition contains calcium chloride in a proportion of 1% by mass or more and glycols in a proportion of 20% by mass or more and 40% by mass or less, and the airlaid nonwoven fabric layer has a thickness of 0.5 mm or more and a density of 0.2 g / cm 3 as follows.

[0006] Aspect 2 is the wet sheet of Aspect 1, wherein the content of the liquid composition is 150% by mass or more and 400% by mass or less with respect to the dry mass of the airlaid nonwoven fabric layer. Aspect 3 is the wet sheet according to Aspect 1 or Aspect 2, and is for wiping the buttocks.

Advantages of the Invention

[0007] According to the present invention, it is possible to obtain a wet sheet that is excellent in flexibility and strength and has improved hydrolyzability.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] An embodiment of the wet sheet of the present invention will be described. The wet sheet includes an airlaid nonwoven fabric layer and a liquid composition impregnated in the airlaid nonwoven fabric layer.

[0010] The airlaid nonwoven fabric layer contains carboxymethyl cellulose in a proportion of 1% by mass or more and 10% by mass or less. The liquid composition contains calcium chloride in a proportion of 1% by mass or more and glycols in a proportion of 20% by mass or more and 40% by mass or less.

[0011] Hereinafter, the details of the wet sheet will be described. <Airlaid Nonwoven Fabric Layer> The airlaid nonwoven fabric layer means a layer of airlaid nonwoven fabric produced by the airlaid manufacturing method. The type of fiber used as the raw material of the airlaid nonwoven fabric is not particularly limited, but pulp fiber is preferably used.

[0012] Examples of pulp fibers include fibers composed of wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include chemical pulps such as hardwood pulp (hereinafter also referred to as "LBKP"; similarly abbreviated hereinafter), softwood pulp (NBKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen-bleached kraft pulp (OKP), etc.

[0013] In addition, semi-chemical pulps such as semi-chemical pulp (SCP) and chemigroundwood pulp (CGP), and mechanical pulps such as groundwood pulp (GP) and thermomechanical pulp (TMP, BCTMP) can also be used.

[0014] Examples of non-wood pulp include cotton-based pulps such as cotton linter and cotton lint, non-wood-based pulps such as hemp, wheat straw, and bagasse, cellulose, chitin, chitosan, etc. isolated from jellyfish and seaweed, etc.

[0015] Examples of deinked pulp include deinked pulp made from waste paper as a raw material. Among these, using NBKP is preferable because it is easy to improve the strength of the airlaid nonwoven fabric.

[0016] The length of the pulp fibers is not particularly limited, but the average fiber length of the pulverized pulp is about 1 to 5 mm. The method for measuring the length of the pulp fibers is not particularly limited, but for example, it can be determined as the length-weighted average fiber length using a fiber length measuring device FS-200 (manufactured by Kajaani).

[0017] The airlaid nonwoven fabric layer contains carboxymethyl cellulose as a binder. <Carboxymethyl cellulose> Carboxymethyl cellulose as a binder (hereinafter also referred to as "CMC") is not particularly limited, and known CMC can be used.

[0018] The airlaid nonwoven fabric layer contains CMC in a proportion of 1% by mass or more and 10% by mass or less. By having the CMC content in the range of 1% by mass or more and 10% by mass or less, the flexibility and strength of the airlaid nonwoven fabric layer in the wet sheet during use can be made suitable. Also, since CMC has high solubility in water, when the wet sheet comes into contact with a large amount of water, such as being flushed down the toilet after use, CMC dissolves quickly in water. When CMC dissolves quickly in water, the fibers constituting the airlaid nonwoven fabric layer are likely to become separated. That is, the hydrolyzability of the wet sheet can be improved.

[0019] Note that the above CMC content means the ratio of the mass of CMC to the total mass of the airlaid nonwoven fabric layer excluding the liquid composition and CMC. The CMC content is preferably 1% by mass or more and 7% by mass or less, and more preferably 1% by mass or more and 5% by mass or less.

[0020] The airlaid nonwoven fabric layer may contain a water-soluble or water-swellable binder other than carboxymethyl cellulose. Examples of binders other than carboxymethyl cellulose include polysaccharide derivatives other than carboxymethyl cellulose, natural polysaccharides, synthetic polymers, and the like.

[0021] Specific examples of polysaccharide derivatives other than carboxymethyl cellulose include, for example, carboxyethyl cellulose, carboxymethylated starch or its salts, starch, methyl cellulose, ethyl cellulose, and the like.

[0022] Specific examples of natural polysaccharides include, for example, guar gum, tragacanth gum, xanthan gum, sodium alginate, carrageenan, gum arabic, gelatin, casein, and the like.

[0023] Specific examples of synthetic polymers include polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer resin (EVA), polyvinyl alcohol derivatives, polymers or copolymers of unsaturated carboxylic acids, and salts thereof.

[0024] <Shape of the airlaid nonwoven fabric layer> As shown in FIG. 1, the airlaid nonwoven fabric layer 10 has a thickness T1 of 0.5 mm or more and a density of 0.2 g / cm 3 as follows.

[0025] The thickness T1 of the airlaid nonwoven fabric layer 10 is preferably 2 mm or less, more preferably 1 mm or less. On the other hand, when the thickness is 0.5 mm or more, it becomes easier to suppress the leakage of dirt when the wet sheet is used for wiping the buttocks. Further, when the thickness T1 of the airlaid nonwoven fabric layer 10 is 2 mm or less, it becomes easier to improve the flexibility of the airlaid nonwoven fabric layer 10. Thereby, it becomes easier to improve the flexibility of the wet sheet.

[0026] Further, when the density of the airlaid nonwoven fabric layer 10 is 0.2 g / cm 3 or less, it becomes easier to improve the flexibility of the wet sheet. Furthermore, in addition to the thickness T1 of the airlaid nonwoven fabric layer 10 being 0.5 mm or more, when the density of the airlaid nonwoven fabric layer 10 is 0.2 g / cm 3 or less, it is possible to suppress the leakage of dirt while improving the flexibility. The lower limit of the density of the airlaid nonwoven fabric layer 10 is not particularly limited.

[0027] Note that, as described later, the density of the airlaid nonwoven fabric layer 10 means the density at the location with the highest density in the airlaid nonwoven fabric layer 10, that is, the maximum density. As shown in FIG. 2, the airlaid nonwoven fabric layer 10 may have irregularities on its surface. For example, the airlaid nonwoven fabric layer 10 may have irregularities on its surface due to being curved in a wave shape. In other words, it may have recesses 11 on its surface. In this case, the thickness T1 of the airlaid nonwoven fabric layer 10 shall mean the apparent thickness including the recesses 11 of the airlaid nonwoven fabric layer 10.

[0028] Also, in FIG. 2, when the density of the airlaid nonwoven fabric layer 10 is 0.2 g / cm 3 The following refers to considering the highest density calculated from the unit volume based on the actual thickness T2 of the airlaid nonwoven fabric layer 10. And in the interior P of the airlaid nonwoven fabric layer 10, it shall mean that the highest density is 0.2 g / cm 2 or less. On the other hand, the density calculated from the unit volume based on the apparent thickness T1 of the airlaid nonwoven fabric layer 10 shall be referred to as the average density or the apparent density.

[0029] As shown in FIG. 3, the airlaid nonwoven fabric layer 10 may have recesses 11 formed by being locally compressed. For example, the airlaid nonwoven fabric layer 10 may have recesses 11 on its surface due to being compressed from one side of the surface. In this case, the thickness T1 of the airlaid nonwoven fabric layer 10 shall mean the thickness T1 of the non-compressed portion of the airlaid nonwoven fabric layer 10.

[0030] Also, in FIG. 3, when the density of the airlaid nonwoven fabric layer 10 is 0.2 g / cm 3 The following refers to considering the highest density per unit volume based on the thickness T2 to the bottom of the recess 11 of the airlaid nonwoven fabric layer 10. And in the interior P of the airlaid nonwoven fabric layer 10, it shall mean that the highest density is 0.2 g / cm 3 or less.

[0031] The highest density of the airlaid nonwoven fabric layer 10 can be calculated, for example, by cutting out the portion of the above thickness T2 and measuring the mass per unit volume of the cut-out portion. The basis weight of the airlaid nonwoven fabric layer 10 is not particularly limited, but is preferably 30 g / m 2 or more and 100 g / m 2 or less, more preferably 40 g / m 2 or more and 80 g / m 2 or less.

[0032] <Liquid composition> The liquid composition uses water as a medium and contains calcium chloride and glycols. (Calcium chloride) Calcium chloride is used as a crosslinking agent. The type of calcium chloride is not particularly limited, and known calcium chloride can be used. The liquid composition contains calcium chloride at a ratio of 1% by mass or more. When the liquid composition contains calcium chloride within the above numerical range, the CMC contained in the airlaid nonwoven fabric can be preferably crosslinked. By preferably crosslinking CMC, the solubility of CMC in water can be reduced, so that the shape of the airlaid nonwoven fabric layer in the wet sheet during use is easily maintained.

[0033] In addition, since calcium chloride has high solubility in water, it dissolves rapidly in water when it comes into contact with a large amount of water such as flushing it into the toilet after use of the wet sheet. Therefore, it becomes possible to dissolve CMC rapidly in water.

[0034] The content of calcium chloride is preferably 1% by mass or more and 7% by mass or less, more preferably 1% by mass or more and 5% by mass or less. (Glycols) Glycols are used as a moisturizing organic solvent. Glycols mean compounds having a structure in which hydroxy groups are respectively bonded to two carbon atoms of aliphatic hydrocarbons. The type of glycols is not particularly limited, and known glycols can be used.

[0035] The liquid composition contains glycols in a proportion of 20% by mass or more and 40% by mass or less. When the liquid composition contains glycols within the above numerical range, it becomes easier to maintain the state in which CMC is cross-linked with calcium chloride and insolubilized. Therefore, it becomes easier to maintain the strength of the airlaid nonwoven fabric layer in the wet sheet during use.

[0036] In addition, since glycols have high solubility in water, when the airlaid nonwoven fabric layer is brought into contact with a large amount of water such as flushing it down the toilet after use of the wet sheet, they dissolve quickly in water. When glycols dissolve quickly in water, it further becomes possible to dissolve CMC quickly in water.

[0037] The content of glycols is preferably 25% by mass or more and 35% by mass or less, and more preferably 27% by mass or more and 33% by mass or less. Specific examples of glycols include, for example, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol (DPG), butylene glycol, hexylene glycol, and the like.

[0038] As the glycols, one of the above-mentioned glycols may be used alone, or two or more thereof may be used in combination. (Other components) The liquid composition may contain known other components used in the liquid composition of the wet sheet. Examples of other components include, for example, preservatives, surfactants, bactericides, deodorants, thickeners, fragrances, colorants, and the like.

[0039] The content of water as a medium in the liquid composition is not particularly limited, but is preferably 50% by mass or more, and more preferably 60% by mass or more. Also, it is preferably 89% by mass or less, and more preferably 80% by mass or less.

[0040] The content of the liquid composition in the wet sheet is not particularly limited. It is preferably 50% by mass or more and 500% by mass or less, more preferably 100% by mass or more and 450% by mass or less, and even more preferably 150% by mass or more and 400% by mass or less with respect to the dry mass of the airlaid nonwoven fabric layer. The content of the liquid composition is also referred to as the impregnation amount.

[0041] The liquid composition is also referred to as a drug or an aqueous drug. <Method for manufacturing a wet sheet> The method for manufacturing a wet sheet is not particularly limited, and a known method for manufacturing a wet sheet can be adopted. For example, first, an airlaid nonwoven fabric layer with CMC attached is created by spraying an aqueous CMC solution onto a fiber web layer formed by the airlaid method and then drying it.

[0042] Next, calcium chloride and glycols are mixed in water as a medium and stirred to prepare a liquid composition. A wet sheet can be produced by impregnating the obtained liquid composition into the airlaid nonwoven fabric layer. The obtained wet sheet may be packaged in a known package in a stacked state of a plurality of sheets.

[0043] <Uses of the wet sheet> The uses of the wet sheet are not particularly limited. For example, it can be used as a sweat wiping sheet, a foot wiping sheet, a cleaning sheet, a nursing care wiping sheet, a sheet for removing bacteria and viruses, etc. Targets for using the cleaning sheet include dining tables, cooking tables, kitchen counters, floors, walls, furniture, cupboards, mirrors, windows, doors, toilets, etc. The nursing care wiping sheet can be used for wiping the buttocks. Among these, the wet sheet of the present embodiment is most preferably used for wiping the buttocks in nursing care, which is required to be flushed into the toilet for disposal after wiping feces.

[0044] Also, the wet sheet can also be called wet wipes or hydrolyzable articles. <Action and effect> (1) The wet sheet comprises an airlaid nonwoven fabric layer and a liquid composition impregnated in the airlaid nonwoven fabric layer. The airlaid nonwoven fabric layer contains CMC at a ratio of 1% by mass or more and 10% by mass or less, and the liquid composition contains calcium chloride at 1% by mass or more and glycols at a ratio of 20% by mass or more and 40% by mass or less. The airlaid nonwoven fabric layer has a thickness of 0.5 mm or more and a density of 0.2 g / cm 3 or less.

[0045] When the density of the airlaid nonwoven fabric layer is 0.2 g / cm 3 or less, it becomes easier to improve the flexibility of the wet sheet. Also, when the thickness is 0.5 mm or more, it is possible to suppress the seepage of dirt. Further, since the airlaid nonwoven fabric layer contains CMC within the above numerical range and is impregnated with the above liquid composition, the strength of the wet sheet can be improved.

[0046] Therefore, when the wet sheet is brought into contact with a large amount of water such as flushing it into the toilet, CMC can be quickly dissolved in water, so that the hydrolyzability of the wet sheet can be improved. Also, since the flexibility and strength of the airlaid nonwoven fabric layer in the wet sheet during use become suitable, the usability of the wet sheet can be improved.

[0047] (2) The content of the liquid composition is 150% by mass or more and 400% by mass or less with respect to the dry mass of the airlaid nonwoven fabric layer. Since the content of the liquid composition with respect to the wet sheet becomes suitable, the flexibility and strength of the wet sheet are more likely to be excellent.

[0048] (3) After wiping off dirt as a butt wipe, when the wet sheet is flushed into the toilet, it can be quickly dissolved in water and flushed away, so that clogging of the toilet can be preferably suppressed. Also, since it can have a gentle touch on the skin, the usability as a butt wipe can be improved.

Example

[0049] Hereinafter, in order to make the configuration and effects of the present invention more specific, examples etc. will be given, but the present invention is not limited to these examples. (Example 1) As shown in Table 1, an airlaid nonwoven fabric containing CMC was prepared. The airlaid nonwoven fabric containing CMC was produced by spraying an aqueous CMC solution onto a fiber web prepared by the airlaid method and then drying it. As the fibers constituting the airlaid nonwoven fabric, NBKP having an average fiber length of 5 mm or less was used.

[0050] The type and content of the fibers, the type and content of the binder, the manufacturing method of the nonwoven fabric, the basis weight, the thickness, and the average value and maximum value of the density of the airlaid nonwoven fabric layer 10 are shown in Table 1. Also, the type and content of the crosslinking agent contained in the liquid composition, the type and content of the organic solvent, the content of the preservative, the content of water, and the impregnation amount of the liquid composition are shown in Table 1. In Table 1, % means mass %. As the preservative, a known preservative was used. Salt cal means calcium chloride.

[0051] (Examples 2 to 7, Comparative Examples 1 to 9) The type and content of each component of the nonwoven fabric layer and the liquid composition were changed as shown in Table 1 to produce a wet sheet. In Comparative Example 8, paper was used instead of the airlaid nonwoven fabric. In Comparative Example 9, instead of NBKP, a nonwoven fabric made of rayon fibers and pulp as a binder by spunlace was used.

[0052]

Table 1

[0053] (Evaluation Test) For the wet sheets of Examples 1 to 7 and Comparative Examples 1 to 9, flexibility, strength, hydrolysis resistance, and reverse penetration were evaluated. The evaluation method, evaluation criteria, and evaluation results are shown below.

[0054] (Flexibility) The flexibility was evaluated by sensory evaluation by five monitors. Five monitors were actually asked to use it for wiping the buttocks, and they were asked to evaluate the wiping feeling and texture on the skin on a scale of 5 points, and the average value was calculated. Note that the higher the score, the better the wiping feeling and texture. The evaluation was carried out according to the following evaluation criteria. The results are shown in Table 1.

[0055] · Evaluation criteria for flexibility ◎ (Particularly excellent): When it is 4.0 points or more ○ (Excellent): When it is 3.0 points or more and less than 4.0 points × (Unacceptable): When it is less than 3.0 points (Strength) The strength was measured with a tensile strength tester (Tensilon universal testing machine RTG-1210 manufactured by A&D Company). The results are shown in Table 1.

[0056] Note that the strength (MD) means the tensile strength along the running direction (longitudinal direction) during non-woven fabric production. The strength (CD) means the tensile strength along the width direction (transverse direction) during non-woven fabric production. · Evaluation criteria for strength ◎ (Particularly excellent): When the strength (MD) and the strength (CD) are 105 gf / 25 mm or more ○ (Excellent): When the strength (MD) and the strength (CD) are 80 gf / 25 mm or more and at least one of them is less than 105 gf / 25 mm × (Unacceptable): When at least one of the strength (MD) and the strength (CD) is less than 80 gf / 25 mm (Hydrolyzability) The evaluation of hydrolyzability was carried out according to the following procedure. The ease of loosening was measured according to JIS P4501. The evaluation was carried out according to the following evaluation criteria. The results are shown in Table 1.

[0057] · Evaluation criteria for hydrolyzability ◎ (Particularly excellent): When it dissolved in less than 20 seconds ○ (Excellent): When it dissolved in 20 seconds or more and less than 100 seconds × (Unacceptable): When it dissolved in 100 seconds or more or did not dissolve (Lining pull-out property) The evaluation of the penetration resistance was carried out by dropping 1 cc of colored glycerin onto an acrylic plate and wiping it off with a wet sheet. The presence or absence of glycerin adhering to the fingers holding the sheet and the penetration through the sheet surface were visually evaluated. The evaluation was made according to the following criteria. The results are shown in Table 1.

[0058] · Evaluation criteria for penetration resistance ◎ (Particularly excellent): When there was no glycerin adhering to the fingers and almost no penetration of glycerin through the sheet surface was visible even visually ○ (Excellent): When there was no glycerin adhering to the fingers, but glycerin was visible on the sheet surface visually × (Unacceptable): When glycerin penetrated and adhered to the fingers From Table 1, Comparative Examples 2, 4, 6 to 8 had an evaluation of "unacceptable" for flexibility. Also, Comparative Examples 1, 3, and 5 had an evaluation of "unacceptable" for strength. Comparative Example 8 had an evaluation of "unacceptable" for penetration resistance. Also, Comparative Example 9 had evaluations of "unacceptable" for hydrolysis resistance and penetration resistance. In contrast, Examples 1 to 7 were confirmed to have flexibility, strength, hydrolysis resistance, and penetration resistance all at "excellent" or above. It was confirmed that they can be suitably used for wiping the buttocks.

Explanation of symbols

[0059] 10... Airlaid nonwoven fabric layer, 11... Concave portion.

Claims

1. A wet sheet comprising an air-laid nonwoven fabric layer and a liquid composition impregnated in the air-laid nonwoven fabric layer, wherein the air-laid nonwoven fabric layer contains carboxymethyl cellulose in a proportion of 1% by mass or more and 10% by mass or less, the liquid composition contains calcium chloride in a proportion of 1% by mass or more and glycols in a proportion of 20% by mass or more and 40% by mass or less, The airlaid nonwoven fabric layer has a thickness of 0.5 mm or more and a density of 0.2 g / cm 3 or less, and is a wet sheet characterized by this.

2. The wet sheet according to claim 1, wherein the content of the liquid composition is 150% by mass or more and 400% by mass or less based on the dry mass of the air-laid nonwoven fabric layer.

3. The wet sheet according to claim 1 or 2, which is for wiping the buttocks.

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