JP2022008129A - Cleaning sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning sheet excellent in cleaning performance.

SOLUTION: A cleaning sheet comprising a water retention layer, and a scraping layer laminated on the water retention layer and integrated is such that: the water retention layer contains 100 mass% of cellulosic fibers 110 based on the total mass of fibers constituting the water retention layer; and the scraping layer contains based on the total mass of the scraping layer, 30 mass% or more of thermoplastic fibers which contain large-diameter thermoplastic fibers and small-diameter thermoplastic fibers having relatively different fineness, and is formed by an air-laid method. The cleaning sheet contains 10 mass% or more and 90 mass% or less of the thermoplastic fibers, and 10 mass% or more and 90 mass% or less of the cellulosic fibers 110 based on the total mass of the cleaning sheet.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a cleaning tool, and more particularly to a cleaning sheet having excellent cleaning performance against sticky stains such as kogation, scale, and oil.

Conventionally, various forms of cleaning tools for wiping and scraping off dirt have been used in various fields. For example, in cleaning applications such as kitchens, bathrooms, washrooms, toilets, from sinks, ranges, cookware, bathtubs, washbasins, toilets, and walls and floors, scale, water stains, oils, soap scum, scorching, dust. A sheet-shaped cleaning tool (cleaning sheet) for removing stains such as descaling is used. Such a sheet-shaped cleaning tool is required to have cleaning performance that can remove sticky dirt well and does not damage the material of the surface to be cleaned.

For example, in Patent Document 1, an air-laid nonwoven fabric is laminated and integrated on at least one surface of a liquid-retaining sheet for the purpose of providing a cleaning sheet having sufficient polishing property and scraping property against stains without using polishing particles. The cleaning sheet of the composition is disclosed. In Patent Document 1, thermoplastic fibers having different diameters are blended with an air-laid nonwoven fabric, and the tips of the thermoplastic fibers having a large diameter are present on the surface to improve the scraping property. Further, in Patent Document 1, a cellulosic fiber is blended in a liquid-retaining sheet, and by using the cleaning sheet as a wet sheet impregnated with an aqueous detergent, the cleaning agent is applied to the dirt to make it dirty. It is said that it can float.

Japanese Patent Application Laid-Open No. 2003-61885

An object of the present invention is to provide a cleaning sheet having a structure different from that of Patent Document 1 and having excellent cleaning performance against sticky stains such as kogation, scale, and oil.

The present invention for solving the above problems has the following aspects.

[1] A cleaning sheet including a water-retaining layer and a scraping layer laminated and integrated on the water-retaining layer, wherein the water-retaining layer is 100 mass based on the total mass of fibers constituting the water-retaining layer. The scraping layer contains 30% by mass of a thermoplastic fiber containing a large-diameter thermoplastic fiber and a small-diameter thermoplastic fiber having relatively different fineness, based on the total mass of the scraping layer. The cleaning sheet contains 10% by mass or more and 90% by mass or less, and 10% by mass, based on the total mass of the cleaning sheet. A cleaning sheet containing% or more and 90% by mass or less of cellulose-based fibers.

[2] The cleaning sheet according to [1], wherein the water-retaining layer is formed into a sheet by entanglement of the cellulosic fibers.

[3] The cleaning sheet according to [1], wherein the water-retaining layer contains a binder, and the fibers of the cellulosic fibers are adhered to each other by the binder present at the intersection thereof.

[4] The cleaning sheet according to any one of [1] to [3], wherein the integration is performed by fusing the thermoplastic fibers contained in the scraping layer.

[5] The cleaning sheet according to [4], wherein the scraping layer contains a heat-sealing resin, and the integration is strengthened by fusion of the heat-sealing resin.

[6] The cleaning sheet according to any one of [1] to [5], wherein the scraping layer contains a detergency powder.

[7] The cleaning sheet according to any one of [1] to [6], which contains a cleaning liquid.

The cleaning sheet of the present invention is particularly excellent in cleaning performance against sticky dirt, and according to the present invention, dirt on the surface to be cleaned can be removed without damaging the surface to be cleaned. The cleaning sheet of the present invention has excellent water retention, and can be attached to the surface to be cleaned for a long period of time in a moist state to soften the dirt, or to supply water to the surface to be cleaned and become dirty. The cleaning effect is high because it can be scraped off.

It is a micrograph of the cross section of the nonwoven fabric sheet which becomes the water retention layer of this invention. It is a micrograph of the cross section of the nonwoven fabric sheet further containing the thermoplastic fiber.

(Cleaning sheet)
The cleaning sheet of the present invention includes a water-retaining layer and a scraping layer formed by an air-laid method and laminated and integrated with the water-retaining layer (hereinafter, also simply referred to as laminated and integrated). It is a cleaning tool. The cleaning sheet of the present invention contains 10% by mass or more and 90% by mass or less of thermoplastic fibers and 10% by mass or more and 90% by mass or less of cellulosic fibers based on the total mass of the cleaning sheet.

(Water retention layer)
In the present invention, the water-retaining layer has cellulosic fibers as its main component. In the embodiment of the present invention, the water-retaining layer can contain a cellulosic fiber in an amount of 100% by mass based on the total mass of the fibers constituting the water-retaining layer.

Cellulose-based fibers are hydrophilic and can be used in a water-retaining layer to provide water absorption and water retention to cleaning tools. That is, the cleaning tool of the present invention provided with a water-retaining layer made of 100% by mass of cellulosic fibers has high absorbency (water absorption) and retention (water retention) of water and cleaning liquid used at the time of cleaning. .. Therefore, once the cleaning tool of the present invention is impregnated with water or a cleaning agent, the water or cleaning component can be used to clean a wide area of the surface to be cleaned, and cleaning can be performed with a small amount of water or a cleaning agent. It can be done efficiently.

Further, since the cleaning tool of the present invention is in the form of a sheet, it can be easily deformed along the surface to be cleaned. The sheet-shaped cleaning tool (cleaning sheet) of the present invention can be used by being attached to the surface to be cleaned in a state of containing water. At this time, the cleaning sheet of the present invention is as described above. Since it has high water retention, it can be attached to the surface to be cleaned for a long time, and moisture and a cleaning agent can be applied intensively to stains and the like to be removed. Therefore, according to the present invention, a high cleaning effect can be obtained.

As the cellulosic fiber, for example, wood pulp, pulp fiber such as cotton, and recycled fiber such as rayon can be used. The type of fiber may be used alone or in combination.

The water retention layer can be a non-woven fabric. The water retention layer can be made by known methods such as needle punching, spunlace, airlaid and the like. Specifically, for example, a web in which cellulosic fibers are deposited is formed, and the cellulosic fibers in the web are entangled by an entanglement method such as needle punching or spunlacing, or a binder is applied to the web by a chemical bond method. A non-woven fabric sheet serving as a water-retaining layer can be produced by imparting and adhering the fibers of the cellulosic fibers to each other.

In the water-retaining layer produced by a method combining the air raid method and the chemical bond method, the binder exists at the intersection of the cellulosic fibers and can function to fix the fibers to each other.

FIG. 1 shows an electron micrograph of the surface of the nonwoven fabric sheet serving as the water-retaining layer of the present invention. 1 (a) is an image having a magnification of 100 times, and FIG. 1 (b) is an image having a magnification of 400 times, which is a part of FIG. 1 (a). This non-woven fabric sheet contains 100% by mass of cellulosic fibers (pulp) 110 as fibers and a binder (ethylene vinyl acetate copolymer) 120. Cellulose fibers 110 are bonded to each other by a binder 120. The binder 120 is scattered in the non-woven fabric sheet while exhibiting an amoeber-like irregular shape at the intersection of the cellulosic fibers 110 adjacent to each other.

FIG. 2 shows a micrograph of the surface of a reference non-woven fabric sheet further containing a thermoplastic fiber in addition to a cellulosic fiber and a binder. FIG. 2B is a magnified image of a part of FIG. 2A at a magnification of 400 times. Cellulose-based fibers 110 are bonded to each other by a binder 120, or a core-sheath-type thermoplastic fiber (core component is polyester (PET) and sheath component is polyethylene (PE)) (fineness 2.2 dt). , Length 5 mm)) are bonded via fusion of 130. Since the thermoplastic fiber 130 has a certain length, in many cases, one thermoplastic fiber 130 intersects the plurality of cellulosic fibers and adheres to the plurality of cellulosic fibers. Further, the plurality of thermoplastic fibers 130 are also adhered to each other at the intersection.

According to the configuration of the present invention containing 100% by mass of cellulosic fibers as fibers, the amount of water taken in is large, and good water absorption and water retention are achieved, as compared with the configuration of the reference example further containing thermoplastic fibers. It tends to be obtained.

It is presumed that this is not only due to the high blending ratio of the cellulosic fibers having water absorption and water retention in the nonwoven fabric sheet, but also due to the difference in the composition. That is, although it is not desired to be bound by theory, in the nonwoven fabric sheet according to the reference example having the above-mentioned configuration, the swelling of the cellulosic fibers themselves and the spatial space between the fibers when water is added It is believed that the spread tends to be hindered by the binding by the thermoplastic fibers. On the other hand, in the nonwoven fabric sheet according to the present invention, the binder is only scattered at the intersections of the cellulosic fibers, and the swelling of the cellulosic fibers themselves and the spatial spread between the cellulosic fibers tend to be difficult to be hindered. It is believed that there is.

The binder can be an aqueous binder and can be applied to the web by methods such as spraying, for example in the form of an aqueous solution. Non-limiting examples of binders that can be used include, for example, casein, arginsan Na, hydroxyethyl cellulose, carboxymethyl cellulose sodium salt, polyvinyl alcohol, sodium polyacrylic acid, polyacrylic acid ester, acrylic / styrene copolymer, poly. Examples thereof include vinyl acetate, ethylene / vinyl acetate copolymer, acrylonitrile / butadiene copolymer, methyl methacrylate / butadiene copolymer, and styrene / butadiene copolymer.

The proportion of the binder in the water-retaining layer produced by the air-laid method may be an amount necessary and sufficient for adhering the fibers to each other to form a sheet shape. The proportion of the binder is, for example, preferably 30% by mass or less, more preferably 25% by mass or less, based on the total mass of the water-retaining layer (both are converted to absolute dry mass). However, if the proportion of the binder is 10% by mass or less, the strength may be significantly lowered. Further, if the proportion of the binder is too large, the number of adhesion intersections between the fibers of the cellulosic fibers increases, the volume increase in the fibers and between the fibers when water is applied is suppressed, and the fibers are incorporated into the fibers and between the fibers. It is believed that the amount of water that can be produced can be limited.

The larger the rice tsubo, the larger the water absorption of the water retention layer. In the present invention, the paper density of the water-retaining layer is preferably 10 g / m2, more preferably 20 g / m2 or more, still more preferably 20 g / m2 or more, from the viewpoint of absorbency and retention of water and cleaning liquid used at the time of cleaning. It is 30 g / m2 or more. When the water-retaining layer has a large paper density, it can provide cushioning when used as a cleaning tool, and when the worker holds the water-retaining layer side, it can have the effect of being gentle on the worker's hands and fingers. Further, when the water-retaining layer side is applied to the surface to be cleaned, the surface to be cleaned is not easily damaged, and when water or a cleaning liquid is contained, more water can be applied to the surface to be cleaned.

On the other hand, depending on the application of the cleaning tool or the surface to be cleaned, water absorption or water retention of water or cleaning liquid is not required so much, or the cleaning tool itself is required to have flexibility that can be bent along the surface to be cleaned. There is. In such a case, it may be preferable that the paper density of the water holding layer is a small value. The water-retaining rice tsubo can be determined in consideration of the balance with the rice tsubo of the scraping layer.

In the present invention, the water-retaining layer does not require a binder for adhesion between the fibers (in the case of entanglement), or even if it does, the binder is included so as to be scattered at the intersections of the fibers (in the case of airlaid). Therefore, the presence of the binder tends to hinder the water absorption and water retention of the water retention layer, and the water retention layer of the present invention can exhibit good water absorption and water retention.

(Scraping layer)
In the present invention, the scraping layer is a layer provided by laminating and integrating with the above-mentioned water retention layer. The scraping layer of the present embodiment is formed by an air-laid method, and contains 30 masses of thermoplastic fibers including large-diameter thermoplastic fibers and small-diameter thermoplastic fibers having relatively different fineness, based on the total mass of the scraping layer. Included in an amount of% or more.

In the present invention, the large-diameter thermoplastic fiber is relatively thicker than the small-diameter thermoplastic fiber, the large-diameter thermoplastic fiber has a fineness of 10 dtex or more and 200 dtex or less, and the small-diameter thermoplastic fiber has a fineness of 1 dtex or more and 10 dtex or less. Can have the fineness of.

The fiber length of the thermoplastic fiber may be any length suitable for the air-laid method, and can be, for example, a fiber length of 3 mm or more and 10 mm or less.

The type of resin for the thermoplastic fiber can be, for example, polyester, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, nylon, polycarbonate, polylactic acid, or polyetherimide. Composite fibers in which two or more kinds of synthetic resins having different melting points are combined can also be used. Examples of such composite fibers include polyethylene / polypropylene, low melting point polypropylene / polypropylene, polyethylene / polyester, polypropylene / polyester, low melting point polyester / polyester and the like.

Due to the manufacturing method of the scraping layer, many tips of constituent fibers appear on the surface. Thermoplastic fibers generally have moderate rigidity, and their tips can effectively scrape dirt. Large-diameter thermoplastic fibers tend to have a higher ability to scrape so-called sticky hard stains such as kogation than small-diameter thermoplastic fibers. Further, the small-diameter thermoplastic fiber tends to have a higher performance of scraping dirt that has entered into the recesses and gaps of the surface having minute irregularities than the large-diameter thermoplastic fiber. Therefore, it is preferable to appropriately determine the blending ratio of the large-diameter thermoplastic fiber and the small-diameter thermoplastic fiber according to the application. For example, in order to develop good stain detergency against sticky hard stains in the scraping layer, the amount of large-diameter thermoplastic fibers is 10% by mass or more based on the mass of the total thermoplastic fibers in the scraping layer. It is preferable to mix with. However, if the blending ratio is too high, the surface to be cleaned may be damaged, and in order to suppress this, the blending ratio of the large-diameter thermoplastic fiber is preferably limited to 95% by mass. The preferable blending ratio of the large-diameter thermoplastic fiber and the small-diameter thermoplastic fiber is 10:90 to 95: 5 (mass standard).

As described above, in the present invention, the scraping layer is formed by the airlaid method. More specifically, the scraping layer is formed by depositing components containing thermoplastic fibers by an air raid method to form a web, and then heat-treating the thermoplastic fibers to fuse the fibers with each other or with other components. , Can be in the form of a sheet.

The scraping layer can be provided by laminating and integrating the constituent components on the sheet to be the water retention layer by the air raid method. Alternatively, the scraping layer is produced as an air-laid nonwoven fabric separately from the sheet serving as the water-retaining layer, and can be laminated and integrated by joining the two. As a means of joining, that is, integrating, embossing by heat or ultrasonic waves, bonding by hot melt, or the like can be used. Further, the scraping layer may be blended with a heat-fusing resin powder, and the fusion by heat treatment may be utilized to strengthen the bonding between the layers.

Examples of the heat-sealing resin powder that can be used for the scraping layer in order to strengthen the interlayer bonding between the scraping layer and the water-retaining layer include polyethylene, polypropylene, polyester and the like. The shape and size of the powder of these heat-sealing resins may be any as long as they are suitable for the airlaid method, and may be, for example, a granular solid having a particle size in the range of 1 μm to 1000 μm.

The scraping layer may be provided on one side of the water retention layer, or may be provided on both sides. When the scraping layer is provided on one side of the water retention layer, the surface used for cleaning can be changed depending on the type of dirt, and the dirt can be removed efficiently. When the scraping layer is provided on both sides of the water-retaining layer, both sides can be used in the same manner, for example, in cleaning for a dirt having a large degree of sticking, and the frequency of changing the cleaning tool is reduced. When the scraping layers are provided on both sides, the scraping layers on both sides may be the same or different.

The larger the paper density of the scraping layer, the higher the strength and the better the scraping performance against sticky dirt and the like. From the viewpoint of scraping performance, the paper density of the scraping layer is preferably 30 g / m2 or more, more preferably 35 g / m2 or more, and further preferably 40 g / m2 or more. However, as the paper density increases, the flexibility tends to decrease. Depending on the shape of the surface to be cleaned, it may be preferable that the paper density is low so that the cleaning sheet can be deformed along the shape.

The balance between the water retention layer and the scraping layer can be appropriately set. The scraping layer allows water to permeate, but has low water retention. Therefore, for example, in the case of an application in which dirt is softened or dissolved mainly by using water or a cleaning liquid, it is preferable to increase the ratio of the water retention layer. Further, in applications such as when it is desired to remove stains in a dry state or in a state close to dry without containing too much water, the ratio of the scraping layer can be increased. For example, the balance between the water retention layer and the scraping layer can be, for example, 9: 1 to 1: 9, 8: 2 to 2: 8, and 6: 4 to 4 as the ratio of paper density. : 6 can be set. In addition, the balance between the water retention layer and the scraping layer can be set by the thickness.

(Washable powder)
In order to improve the detergency, the cleaning sheet of the present invention can be blended with a material (detergency component) capable of providing detergency, for example, in the form of powder (hereinafter, also referred to as detergency powder). .. The detergency powder can be added to the web feedstock, for example in the formation of the scraping layer.

The type of detergency powder can be determined by the type of dirt to be cleaned. It is desirable to use acidic powder for removing stains such as water stains on faucets, and alkaline powder for stains that exhibit acidity in the kitchen.

Examples of the acidic detergency powder include powders of malonic acid, maleic acid, citric acid, malic acid, tartaric acid, succinic acid, fumaric acid, hyaluronic acid, sodium dihydrogen phosphate and the like.

Examples of the alkaline detergency powder include powders of sodium carbonate, sodium hydrogencarbonate, sodium sesquicarbonate, potassium carbonate, potassium hydrogencarbonate, calcium carbonate, magnesium carbonate, magnesium bicarbonate, calcium bicarbonate and the like.

The detergency powder is preferably blended in a cleaning sheet in a blending amount of 1 g / m2 or more from the viewpoint of exhibiting the effect. Further, if the blending amount is too large, it becomes difficult to remove the cleaning component after cleaning the surface to be cleaned. Therefore, it is desirable to blend in a blending amount of 200 g / m2 or less.

(Washable liquid)
The cleaning sheet of the present invention can also be used by containing a cleaning component in the form of a liquid.

It is desirable that the detergency liquid uses water as a medium and contains a surfactant, a water-soluble solvent, and the components of the detergency powder mentioned above.

Examples of the surfactant include carboxylates, sulfonates, sulfates, amine salts, quaternary ammonium salts and the like. The blending amount of the surfactant in the detergency liquid can be, for example, in the range of 0.01 to 30% by mass.

Examples of the water-soluble solvent include ethanol, isopropanol, propanol, diethylene glycol, glycerin, pyrrolidone and the like. The blending amount of the surfactant in the detergency liquid can be, for example, in the range of 1 to 50% by mass.

The blending amount of the detergency powder in the detergency liquid can be, for example, in the range of 0.01 to 30% by mass.

The detergency liquid can be blended with the cleaning sheet by a method such as spray spraying or impregnation.

(The invention's effect)
The cleaning sheet of the present invention can effectively scrape off sticky stains such as kogation and oil stains by a scraping layer formed by an air raid method and containing thermoplastic fibers. Further, by having a water-retaining layer made of cellulosic fibers, when water or a cleaning liquid is used for cleaning, the absorption / holding power of those liquids is high and the cleaning effect is enhanced. Further, by blending a detergency component in the form of a powder or a liquid having a detergency effect, a polishing effect and a stain dissolving power are imparted, and a higher detergency effect can be obtained.

<Manufacturing method of cleaning sheet>
The method for producing the cleaning sheet of the present invention includes the formation of a water-retaining layer and the formation of a scraping layer. For example, a non-woven fabric sheet to be a water-retaining layer is obtained by a known non-woven fabric manufacturing method such as an air-laid method, a spunlace method, or a needle punching method, and the obtained non-woven fabric sheet is separately produced as a scraping layer by an air-laid method. The cleaning sheet of the present invention can be produced by laminating and integrating the sheets. To integrate the two separately prepared layers, embossing by heat or ultrasonic waves, adhesion using an adhesive, or the like can be performed. Further, for example, when the sheet to be the scraping layer is produced by the air-laid method, the carrier sheet of the air-laid method may be used as the non-woven fabric sheet to be the water-retaining layer according to the present invention.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

[Example 1]
<Manufacturing of non-woven fabric sheet that serves as a water retention layer>
The roll sheet-shaped pulp was defibrated by a pulverizer to obtain short fibers (fiber diameter of about 50 μm, average fiber length of 2 to 3 mm). Using an air-laid web forming device, the staple fibers were deposited on a wire mesh belt while being sucked by a suction box to form a web. Next, in order to bond the fibers of the cellulosic fibers to each other, an appropriate amount of a binder (ethylene vinyl acetate copolymer) was sprayed on the web, and after a drying step, the paper density was 40 g / m2 (of which the amount of the binder was 12). A non-woven fabric sheet (hereinafter, also referred to as a water-retaining layer sheet) serving as a water-retaining layer was obtained.

<Manufacturing of non-woven fabric sheet as a scraping layer>
A core-sheath-type thermoplastic fiber (fineness 35 dt, length 5 mm) in which the core component is polypropylene (PP) and the sheath component is polyethylene (PE), and the core component is polyester (PET) and the sheath component is polyethylene (PE). The core-sheath-type thermoplastic fiber (fineness 2.2 dt, length 5 mm) and the heat-fused resin powder (polyethylene powder, particle size 600 μm) were mixed at a mass ratio of 45:15: 7. A mixture was prepared. Using this mixture as a web raw material, a web was formed using an air-laid web forming apparatus. Next, heat treatment was performed to fuse the thermoplastic fibers to obtain a non-woven fabric sheet (hereinafter, also referred to as a scraping layer sheet) having a paper density of 40 g / m2 and serving as a scraping layer.

<Laminating and integrating the water retention layer and the scraping layer>
The water-retaining layer sheet and the scraping layer sheet are laminated and heat-pressurized, and the thermoplastic fiber and the heat-sealing resin contained in the scraping layer sheet are fused to form the water-retaining layer and the scraping layer. Joined. As a result, a cleaning sheet of Example 1 having a structure in which a scraping layer was laminated and integrated on one side of the water absorption layer was obtained.

[Example 2]
A cleaning sheet of Example 2 was obtained in the same manner as in Example 1 except that the paper density of the water-retaining layer sheet was set to 60 g / m2.

[Example 3]
A cleaning sheet of Example 3 having a paper density of 130 g / m2 was obtained in the same manner as in Example 1 except that baking soda was further added to the web raw material for the scraping layer sheet. In this example, the blending amount of baking soda was 70 g / m2.

[Comparative Example 1]
The constituent fibers of the water-retaining layer sheet are 100% by mass of pulp, 80% by mass of pulp, and a core-sheath-type thermoplastic fiber (fineness 2.2 dt, length) in which the core component is polyester (PET) and the sheath component is polyethylene (PE). The cleaning sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that it was replaced with 20% by mass (5 mm).

[Comparative Example 2]
The constituent fibers of the water-retaining layer sheet are 100% by mass of pulp, 60% by mass of pulp, and a core-sheath-type thermoplastic fiber (fineness 2.2 dt, length) in which the core component is polyester (PET) and the sheath component is polyethylene (PE). The cleaning sheet of Comparative Example 2 was obtained in the same manner as in Example 2 except that it was replaced with 40% by mass (5 mm).

<Evaluation>
The following performance evaluations were performed on the cleaning sheets of Examples and Comparative Examples.

I. Evaluation items and evaluation methods (water retention)
As test pieces, the cleaning sheets of Examples 1 and 2 and Comparative Examples 1 and 2 were cut into flat plates having a size of 10 cm × 10 cm, and the weights were measured, which were used as the initial weights. The test piece was immersed in distilled water for 1 minute and then placed on a wire mesh for 1 minute, and then the weight was measured, which was taken as the water holding weight in the horizontal direction. After that, the weight after suspending the test piece by sandwiching one corner of the test piece with a clip for 1 minute was measured, and this was taken as the water holding weight in the vertical direction. The amount of water retained per volume (horizontal and vertical) was determined by dividing the value obtained by subtracting the initial weight from each of the horizontal water holding weight and the vertical water holding weight by the volume. It was evaluated that the larger the value, the better the water retention.

(Cleanability)
Place 0.07 g of a mixture of commercially available sugar and soy sauce in a mass ratio of 3: 1 on a stainless steel vat, and while heating the vat with an electric heater, stir and spread the mixture on the vat with a spatula to spread the water. Was skipped to produce a koge with a diameter of about 30 mm. In addition, a detergent diluted solution was prepared by diluting a commercially available dishwashing detergent 100 times with water.

As test pieces, the cleaning sheets of Examples 1 to 3 and Comparative Examples 1 and 2 were cut into flat plates having a size of 30 mm × 30 mm, immersed in a detergent diluent for 1 minute, then taken out, and one side of the test piece was clipped. Suspended vertically for 1 minute. This test piece was placed on the part of the bat where the kogation was located, lightly pressed by hand and reciprocated 30 times to rub the koge, and the state of the koge remaining on the bat was confirmed. Based on the area of the kogation before rubbing (a circle with a diameter of about 30 mm), the ratio of the area of the kogation removed by rubbing was taken as the removal rate. The higher the removal rate, the better the stain removal and the better the detergency. Here, according to the criteria shown in the table below, a three-stage evaluation is performed when the removal rate is 90% or more, 70% or more and less than 90, and 70% or less, and the one with the best detergency is selected first. It is shown using the reference numerals A, B, and C.

II. Evaluation Results The table below shows the outline of the composition of the cleaning sheets of Examples and Comparative Examples and the results of the evaluation test.

Regarding the water retention property, the example in which the fiber of the water retention layer was made of 100% by mass of the cellulosic fiber was better than the comparative example. There was no difference due to the paper density.

Regarding the detergency, when Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2 are compared with each other as test pieces having the same paper density in the water-retaining layer, the fibers of the water-retaining layer start from 100% by mass of cellulosic fibers. Example was better than the comparative example. Further, when Example 1 and Example 2 and Comparative Example 1 and Comparative Example 2 are compared with each other as test pieces having the same constituent components, the test piece having a large paper density in the water-retaining layer is superior in detergency. rice field.

Further, Example 3 to which a detergency component is added is superior in detergency to Example 1 having the same configuration as that of Example 3 except that it does not contain a detergency component, and although it does not contain a detergency component, it is a water-retaining layer. It showed excellent detergency comparable to that of Example 2 in which the rice tsubo was large.

Claims (7)

A cleaning sheet including a water-retaining layer and a scraping layer laminated and integrated with the water-retaining layer.
The water-retaining layer contains 100% by mass of cellulosic fibers based on the total mass of the fibers constituting the water-retaining layer.
The scraping layer contains thermoplastic fibers containing relatively different fineness of large-diameter thermoplastic fibers and small-diameter thermoplastic fibers in an amount of 30% by mass or more based on the total mass of the scraping layer, and is air-laid. Formed by law,
The cleaning sheet is a cleaning sheet containing 10% by mass or more and 90% by mass or less of thermoplastic fibers and 10% by mass or more and 90% by mass or less of cellulosic fibers based on the total mass of the cleaning sheet. .. The cleaning sheet according to claim 1, wherein the water-retaining layer is formed in the form of a sheet by entanglement of the cellulosic fibers. The cleaning sheet according to claim 1, wherein the water-retaining layer contains a binder, and the fibers of the cellulosic fibers are bonded to each other by the binder present at the intersection thereof. The cleaning sheet according to any one of claims 1 to 3, wherein the integration is performed by fusing the thermoplastic fibers contained in the scraping layer. The cleaning sheet according to claim 4, wherein the scraping layer contains a heat-sealing resin, and the integration is strengthened by fusion of the heat-sealing resin. The cleaning sheet according to any one of claims 1 to 5, wherein the scraping layer contains a detergency powder. The cleaning sheet according to any one of claims 1 to 6, which contains a detergency liquid.

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