Cleaning sheet and cleaning method using the same

Abstract

To provide a cleaning sheet which is easy to use and prevents wiped dust from scattering.SOLUTION: The cleaning sheet 10 can be wrapped around, for example, a cleaning tool or a limb of a worker to perform cleaning. The cleaning sheet 10 is a sheet of ester-based polyurethane foam in which cells 12 are exposed on the surface. The cleaning sheet 10 is flexible and self-adhesive. The thickness of the cleaning sheet 10 is 2. 0mm or less. Further, the cleaning sheet 10 has a consistency equal to or less than 100kg / m3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cleaning sheet and a cleaning method using the cleaning sheet. [Background technology]

[0002] It is common to wrap a cloth around a stick to clean gaps (see, for example, Patent Document 1). The cleaning tool in Patent Document 1 has holes and irregularities formed in the stick to make it easier to wrap the cloth around the stick. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-279214 Summary of the Invention [Problem to be solved by the invention]

[0004] The cleaning tool in Patent Document 1 is inconvenient to use because it requires a dedicated stick and the cloth to be removed from the stick after cleaning. Also, when removing the cloth from the dedicated stick, dust and other debris attached to the cloth may fall off or fly around.

[0005] The present invention has been proposed in view of the above-mentioned problems associated with the conventional technology in order to solve these problems in an appropriate manner, and aims to provide a cleaning sheet that is easy to use and does not easily scatter wiped-away dirt, and a cleaning method using this cleaning sheet. [Means for solving the problem]

[0006] A first aspect of the cleaning sheet according to the present invention is as follows: It is an ester polyurethane foam sheet with cells exposed on the surface, The sheet is flexible and self-adhesive; The thickness of the sheet is 2.0 mm or less, The density of the sheet is 100 kg / m 3 The gist is as follows.

[0007] A second aspect of the cleaning sheet according to the present invention is the cleaning sheet according to the first aspect, The ester-based polyurethane foam may have a cell count of 100 cells / 25 mm or less.

[0008] A third aspect of the cleaning sheet according to the present invention is the cleaning sheet according to the first or second aspect, The hardness of the sheet may be 300N or less.

[0009] An example of a cleaning method according to the present invention is characterized in that the cleaning sheet according to any one of the first, second, and third aspects is wrapped around a cleaning tool or the hands and feet of a worker to perform cleaning. [Effects of the Invention]

[0010] The cleaning sheet according to the present invention is easy to use and does not easily scatter wiped-away dirt.

[0011] According to the cleaning method using the cleaning sheet of the present invention, cleaning can be performed using a cleaning sheet that is easy to use. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view showing a cleaning sheet according to an embodiment of the present invention. [Figure 2] 1A to 1C are explanatory diagrams showing an example of use of the cleaning sheet according to the embodiment. [Figure 3] 10A and 10B are explanatory diagrams showing another example of use of the cleaning sheet according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, a cleaning sheet and a cleaning method using the cleaning sheet according to the present invention will be described below by way of preferred embodiments with reference to the accompanying drawings. Note that the embodiments and drawings described below exemplify some of the embodiments of the present invention, and are not intended to limit the scope of the present invention, and may be modified as appropriate within the scope of the gist of the present invention.

[0014] In this specification, when a numerical range is indicated using "to", it is meant to include the lower limit and the upper limit unless otherwise specified.

[0015] (cleaning sheets) As shown in FIG. 1 , the cleaning sheet 10 of the present invention is an ester-based polyurethane foam sheet with cells 12 exposed on its surface. The cleaning sheet 10 is flexible. Furthermore, the cleaning sheet 10 is self-adhesive. Here, self-adhesive refers to the ability of cleaning sheets 10 to adhere to each other without the use of adhesives or pressure-sensitive adhesives when brought into contact with each other, for example, by bending or rolling the cleaning sheets 10 to overlap each other. The adhered cleaning sheets 10 maintain their adhesion unless an external force is applied, and can be released by applying an external force. The self-adhesive properties of the cleaning sheet 10 are thought to result from a combination of frictional forces, anchoring effects in which the unevenness of the cells 12 exposed on the sheet surface intertwines with each other, intermolecular interactions due to intermolecular forces based on the polarity of the polyurethane foam, and electrical effects based on static electricity charged to the polyurethane foam. Ester-based polyurethane foam is particularly preferred because it enhances self-adhesion due to the strong intermolecular forces between the ester groups contained in the ester-based polyurethane foam.

[0016] The ester-based polyurethane foam constituting the cleaning sheet 10 may be one that has been subjected to a film-removing treatment. Film-removed ester-based polyurethane foam can improve the flexibility and extensibility of the cleaning sheet 10 compared to one that has not been subjected to a film-removing treatment. This weakens the restoring force of the cleaning sheet 10 when the cleaning sheet 10 is bent or rolled to self-adhere at overlapping portions, making it easier to maintain the adhered state. Film-removing treatment is a well-known process for removing the cell membrane of polyurethane foam, and includes methods such as immersing the polyurethane foam in an alkaline solution to melt the cell membrane, or placing the polyurethane foam in a sealed container, filling the sealed container with a flammable gas such as oxygen, and igniting the container to cause an explosion and destroy the cell membrane.

[0017] When ester-based polyurethane foam is compressed (heat pressed), the surface cells are crushed by the heat, increasing its smoothness, making it more difficult to obtain the anchoring effect caused by the cells 12 catching on each other compared to a non-compressed product. For this reason, it is preferable that the cleaning sheet 10 is a non-compressed ester-based polyurethane foam that has not been compressed. When the cleaning sheet 10 is a non-compressed ester-based polyurethane foam, the surface cells 12 are not crushed, making it easier to obtain the anchoring effect caused by the cells 12 catching on each other, improving self-adhesion.

[0018] (Thickness) The thickness of the cleaning sheet 10 is 2.0 mm or less. The thickness of the cleaning sheet 10 is preferably in the range of 0.4 mm to 2.0 mm, more preferably in the range of 0.4 mm to 1.5 mm, and even more preferably in the range of 0.4 mm to 1.0 mm. If the thickness of the cleaning sheet 10 is 2.0 mm or less, when the cleaning sheet 10 is bent or rolled and the overlapping portions are self-adhesively adhered, the restoring force of the cleaning sheet 10 to its original shape can be weakened, making it easier to maintain the self-adhesive state. If the cleaning sheet 10 is too thick, the restoring force of the cleaning sheet 10 becomes too strong, making it difficult to maintain the self-adhesive state. On the other hand, if the cleaning sheet 10 is too thin, the cleaning sheet 10 becomes more easily torn and is difficult to process. Furthermore, the cleaning sheet 10's ability to retain dirt such as dust is reduced.

[0019] (density) The density of the cleaning sheet 10 is 100 kg / m 3 The density of the cleaning sheet 10 is 25 kg / m 3 ~100kg / m 3 The range is preferably 28 kg / m 3 ~78kg / m 3 More preferably, it is in the range of 28 kg / m 3 ~50kg / m 3 It is more preferable that the density of the cleaning sheet 10 is in the range of 100 kg / m 3 If the density is less than this, the cleaning sheet 10 can be made lighter. This weakens the restoring force of the cleaning sheet 10 when it is bent or rolled to self-adhere the overlapping portions, making it easier to maintain the self-adhesion state. If the density of the cleaning sheet 10 is too high, the cleaning sheet 10 becomes heavy and its restoring force increases, making it difficult to maintain the self-adhesion state. Furthermore, if the density of the cleaning sheet 10 is too low, it becomes difficult to produce an ester-based polyurethane foam. In this disclosure, the density is a value measured based on JIS K7222:2005.

[0020] (Number of cells) The cell count of the ester-based polyurethane foam is preferably 100 cells / 25 mm or less. The cell count of the ester-based polyurethane foam is preferably in the range of 15 cells / 25 mm to 100 cells / 25 mm, more preferably in the range of 19 cells / 25 mm to 100 cells / 25 mm, and even more preferably in the range of 40 cells / 25 mm to 91 cells / 25 mm. When the cell count of the cleaning sheet 10 is 100 cells / 25 mm or less, the anchoring effect of the unevenness of the cells 12 exposed on the sheet surface intertwining with each other is strengthened, improving self-adhesion. If the cell count of the cleaning sheet 10 is too high, it tends to become clogged with dust and other debris, and the anchoring effect of the unevenness of the cells exposed on the sheet surface intertwining with each other tends to be weakened. On the other hand, if the cell count of the cleaning sheet 10 is too low, it tends to be difficult to retain dust and other debris, and the anchoring effect of the unevenness of the cells exposed on the sheet surface intertwining with each other tends to be weakened. In this disclosure, the cell count is a value measured based on JIS K6400-1:2004 Appendix 1 (Reference). In ester-based polyurethane foam, the cells may have a uniform shape or may have a variable shape. Furthermore, by changing the cell count (cell coarseness) of the cleaning sheet 10 depending on the target to be cleaned, the cleaning sheet 10 can appropriately capture the dirt on the target to be cleaned.

[0021] (Hardness) The hardness of the cleaning sheet 10 is preferably 300 N or less. The hardness of the cleaning sheet 10 is more preferably in the range of 100 N to 250 N, and even more preferably in the range of 108 N to 215 N. When the hardness of the cleaning sheet 10 is 300 N or less, when the cleaning sheet 10 is bent or rolled to self-adhere at overlapping portions, the restoring force of the cleaning sheet 10 to its original shape can be weakened, making it easier to maintain the self-adhesive state. If the cleaning sheet 10 is made too hard, the restoring force of the cleaning sheet 10 becomes too large, making it difficult to maintain the self-adhesive state. On the other hand, if the cleaning sheet 10 is made too soft, the cleaning sheet 10 becomes difficult to handle. In the present disclosure, the hardness is a value measured based on JIS K6400-2:2012D method.

[0022] (stretch) The elongation of the cleaning sheet 10 is preferably 100% or more. The elongation of the cleaning sheet 10 is preferably in the range of 100% to 700%, more preferably in the range of 150% to 700%, and even more preferably in the range of 211% to 553%. When the elongation of the cleaning sheet 10 is 100% or more, the anchoring effect between the cells 12 exposed on the sheet surface can be increased, thereby improving self-adhesion. Note that in the present disclosure, the elongation is a value measured based on JIS K6400-5:2012.

[0023] The cleaning sheet 10 tends to become softer (less hard) and more stretchable (more stretchable) as the cells become finer (larger cell count).The cleaning sheet 10 tends to have better self-adhesion as the cell count increases and the sheet becomes softer and more stretchable.Furthermore, the cleaning sheet 10 is more preferably made of polyurethane foam that has been subjected to a film removal treatment, as this tends to make the sheet softer and more stretchable.

[0024] (ester-based polyurethane foam) Ester-based polyurethane foams are obtained from compositions containing polyol and polyisocyanate. Here, the term "ester-based polyurethane foam" refers to foams using 50% by weight or more of polyester polyol as the raw polyol. Polyester polyols are preferably used in an amount of 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

[0025] (Polyol) The polyester polyol may be a polyester polyol used in the production of urethane foam. Suitable polyester polyols include those obtained by polycondensation of an aliphatic carboxylic acid such as malonic acid, succinic acid, or adipic acid with a polyol such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, sorbitol, or sucrose, as well as lactone-based polyols obtained by ring-opening lactones. Only one type of polyester polyol may be used, or two or more types may be used.

[0026] The number of functional groups of the polyester polyol is preferably from 2.0 to 5.0, more preferably from 2.0 to 4.0, and even more preferably from 2.0 to 3.0.

[0027] The hydroxyl value of the polyester polyol is preferably from 30 mgKOH / g to 100 mgKOH / g, more preferably from 35 mgKOH / g to 80 mgKOH / g, still more preferably from 40 mgKOH / g to 70 mgKOH / g, and particularly preferably from 45 mgKOH / g to 65 mgKOH / g.

[0028] As polyols other than polyester polyols, polyols used in the production of urethane foams, such as polyether polyols and polyether ester polyols, can be used as appropriate within the scope of the present invention.

[0029] (Isocyanate) The raw material isocyanate may be any of aromatic isocyanate, aliphatic isocyanate, and alicyclic isocyanate. Examples of aromatic isocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polymeric MDI (crude MDI), xylylene diisocyanate, and 1,5-naphthalene diisocyanate. Tolylene diisocyanate (TDI) includes isomers 2,4'-tolylene diisocyanate (2,4'-TDI) and 2,6'-tolylene diisocyanate (2,6'-TDI). Examples include T-80, which has a 2,4'-TDI / 2,6'-TDI ratio of 80 / 20, and T-65, which has a 2,4'-TDI / 2,6'-TDI ratio of 65 / 35. Examples of aliphatic isocyanates include hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, etc. Examples of alicyclic isocyanates include cyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), etc. Only one type of isocyanate may be used, or two or more types may be used.

[0030] The composition for obtaining an ester-based polyurethane foam may contain additives such as a foaming agent, a foam stabilizer, a catalyst, a crosslinking agent, a pigment, a plasticizer, a foaming aid, a flame retardant, an antioxidant, and a light stabilizer, as appropriate.

[0031] (Manufacturing method of cleaning sheets) A composition (raw material mixture) containing a polyol and a polyisocyanate is prepared, and this composition is reacted to obtain an ester-based polyurethane foam. The ester-based polyurethane foam is formed into a block shape, for example, by slab molding, although this is not particularly limited. The cleaning sheet 10 is then obtained by reducing the ester-based polyurethane foam to a predetermined thickness, for example, by peeling, and cutting it to a predetermined size. The cleaning sheet 10 may be provided, for example, in the form of a flat sheet or in the form of a roll. When rolled up, the cleaning sheet 10 maintains its shape favorably due to its self-adhesive properties.

[0032] (Cleaning method using cleaning sheets) As shown in FIG. 2, cleaning can be performed by wrapping the cleaning sheet 10 around a cleaning tool 20 and rubbing the cleaning sheet 10 against the object to be cleaned. When attaching the cleaning sheet 10 to the cleaning tool 20, applying tension to the cleaning sheet 10 expands the cells, making them more likely to adhere to each other. Furthermore, the force of the cleaning sheet 10 as it tries to return to its original shape increases the adhesion between the cells, thereby enhancing self-adhesion. As shown in FIG. 3, cleaning can also be performed by wrapping the cleaning sheet 10 around a user's hand and rubbing the cleaning sheet 10 against the object to be cleaned. Because the cleaning sheet 10 has excellent self-adhesion, it can be attached to the cleaning tool 20 or hand simply by wrapping it around the cleaning tool 20 or hand. In other words, there is no need for a shape or structure to secure the cleaning sheet 10 to the cleaning tool 20, and it can be used with any cleaning tool 20. Furthermore, because the cleaning sheet 10 self-adheres when overlapped or wrapped around itself, it can be attached not only to the user's hands but also to their feet. The cleaning sheets 10 may be wrapped in layers in the same place as shown in Figure 2, but other attachment methods are also possible, such as wrapping a portion of the cleaning sheet 10 and wrapping it diagonally. Furthermore, the cleaning tool 20 may be an existing tool such as a broom or brush, or a rod-shaped object such as disposable chopsticks or a toothpick.

[0033] The cleaning sheet 10 is easy to use because it can be easily attached to an object due to its self-adhesive properties. The cleaning sheet 10 is also easy to use because it can be attached to a wide variety of objects. Furthermore, the cleaning sheet 10 is easy to use because it can be easily removed from an object. The cleaning sheet 10 is made of polyurethane foam with exposed cells on its surface, which allows the cells to retain dust and other debris during cleaning and prevents the debris from scattering. Furthermore, when removing the cleaning sheet 10 from an object, simply wrap the dust-covered side inward to dispose of the cleaning sheet 10 without scattering dust and other debris. Because the cleaning sheet 10 is made of polyurethane foam, fibers do not fall off like those found in nonwoven or woven fabrics. The cleaning sheet 10 retains dust and other debris that adheres to it during cleaning using the cells and the electrostatic effect described above, preventing the dust and other debris from scattering. [Example]

[0034] In the examples, polyester polyol A having a functionality of 2.0 to 3.0 and a hydroxyl value of 45 mg KOH / g to 65 mg KOH / g was used. The raw material blends of the ester-based polyurethane foams in Examples 1 to 5 were the same, and the physical properties of the polyurethane foams were controlled by adjusting the production conditions. For the ester-based polyurethane foams in Examples 6 to 8, the physical properties of the polyurethane foams were controlled by, for example, reducing the amount of water blended as a blowing agent compared to Examples 1 to 5. In Examples 1 to 8, polyurethane foams were produced using the aforementioned polyester polyol A. In Example 9, polyester polyol B having a functionality of 2.0 to 3.0 and a hydroxyl value of 45 mg KOH / g to 65 mg KOH / g was used. The ether-based polyurethane foam of Comparative Example 1 used a polyether polyol instead of a polyester polyol as the polyol. In Examples 1 to 9 and Comparative Example 1, the resulting polyurethane foams were rolled to the thicknesses shown in Tables 1 and 2 and 50 mm wide. Examples 1 to 5, 7 to 8 and Comparative Example 1 are film-removed products that have undergone film-removal treatment. Examples 6 and 9 are non-film-removed products that have not undergone film-removal treatment. The density, hardness, cell number and elongation of Examples 1 to 9 and Comparative Example 1 are as shown in Tables 1 and 2. The reference example is a cotton cloth with a thickness of 1.0 mm.

[0035] Each of the sheets in the Examples, Comparative Examples, and Reference Examples was attached to a disposable chopstick by pinching it around the tip of the chopstick and wrapping it around three times while pulling, and then visually inspected for self-adhesion. The results were evaluated as "◎" when the entire wrapped sheet was adhered without any gaps, "◯" when the wrapped sheet was adhered but with some gaps, and "×" when the wrapped sheet was not adhered. The results are shown in Tables 1 and 2.

[0036] [Table 1]

[0037] [Table 2]

[0038] It was confirmed that the sheets of Examples 1 to 9 have self-adhesive properties. Example 2 and Comparative Example 1 have almost the same density, hardness, cell number, and elongation, but it was found that Example 2, which is an ester-based polyurethane foam, has self-adhesive properties, while Comparative Example 1, which is an ether-based polyurethane foam, does not have self-adhesive properties. [Explanation of symbols]

[0039] 10 cleaning sheets, 12 cells, 20 cleaning tools

Claims

1. It is an ester polyurethane foam sheet with cells exposed on the surface, The sheet is flexible and self-adhesive; The thickness of the sheet is 2.0 mm or less, The density of the sheet is 100 kg / m ３ Below is the cleaning sheet.

2. 2. The cleaning sheet according to claim 1, wherein the number of cells in the ester-based polyurethane foam is 100 cells / 25 mm or less.

3. 2. The cleaning sheet according to claim 1, wherein the hardness of the sheet is 300 N or less.

4. A cleaning method comprising wrapping the cleaning sheet according to any one of claims 1 to 3 around a cleaning tool or the hands and feet of a worker to perform cleaning.

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