JP2020146132A - Wet sheet and method for forming oil-proof coating film using this wet sheet - Google Patents

Abstract

To realize useful prevention of oil stains by making the surface of the base material oil-repellent, in which even if the content of fluorine-based compound in liquid composition is reduced, an oil-proof coating film is formed on the surface of the base material when it moves along the surface of the base material.SOLUTION: There is provided a wet sheet in which a sheet base material is impregnated with a liquid composition containing a hydrophilic oil-repellent agent of a fluorine-based compound represented by the formula (1), a film-forming agent of polyacrylic acid, and a solvent. The solvent is at least one alcohol and water in the range of 1 to 3 carbon atoms. It is satisfied that by mass ratio, fluorine-based compound: polyacrylic acid: alcohol: water=(0.001 to 0.1) :( 0.1 to 4) :( 25 to 55) :( 40 to 75). The sheet base material consists of a non-woven fabric with a texture of 30 to 100 g/m2 and a breathability of 1 to 250 cm3/cm2/sec, contains fluorine-based compound in the liquid composition at a ratio of 0.01 to 50 mg/m2 per unit area of the non-woven fabric, and contains water or a liquid content of water and alcohol in a ratio of 1 to 50 g/m2 with respect to the non-woven fabric in a water equilibrium state.SELECTED DRAWING: None

Description

In the present invention, even if the content of the fluorine-based compound in the liquid composition is reduced, when it moves along the surface of the base material, an oil-proof coating film is formed on the surface of the base material, and the surface of the base material is oil-repellent. The present invention relates to a wet sheet that helps prevent oil stains and a method for forming an oil-proof coating film using the wet sheet.

Conventionally, as a wet sheet of this kind, the applicant has added 0.1 to 10% by mass of a nitrogen-containing fluorine compound represented by the following general formula (24) and one or two having 1 to 4 carbon atoms. We have proposed a wet sheet in which a sheet base material is impregnated with a liquid composition containing 4.9 to 80% by mass of alcohol of seeds or more and 95 to 10% by mass of water (Patent Document 1 (Claim 1 and 2). reference.). This sheet base material is composed of a non-woven fabric having a grain size of 30 to 100 g / m ² and a breathability of 1 to ²⁰⁰ cm ³ / cm ² / sec, and contains nitrogen-containing fluorine-based compounds in the liquid composition per unit area of the non-woven fabric. It is contained at a ratio of 0.1 to 5.0 g / m ² , and contains water or a liquid content of water and alcohol in a ratio of 1.0 to 50 g / m ² with respect to 100% by mass of the non-woven fabric in a water equilibrium state. ..

In the above formula (24), Rf ¹ and Rf ² are linear or branched perfluoroalkyl groups having 1 to 6 carbon atoms, which are the same or different from each other. Further, Rf ³ has 1 to 6 carbon atoms and is a linear or branched perfluoroalkylene group. Further, Z is any one hydrophilic imparting group selected from the group consisting of nonionic type, cationic type, anionic type and amphoteric type.

JP-A-2018-197322

However, the liquid composition that invades the wet sheet shown in Patent Document 1 does not contain a film-forming agent, and is only a nitrogen-containing fluorine-based compound having a structure represented by the formula (24) and a solvent. Therefore, there is a problem that the film does not have hydrophilic and oil-repellent properties unless the liquid composition contains a relatively large amount of fluorine-based compounds. Further, when a nitrogen-containing fluorine-based compound having a structure represented by the formula (24) and a film-forming agent are combined in an attempt to reduce the content of the fluorine-based compound in the liquid composition, the formed film is rainbow-colored. There is a problem that it is difficult to obtain a film having a good appearance due to the occurrence of interference fringes. Therefore, there has been a demand for a wet sheet in which a good film-forming property can be obtained by using a liquid composition in which a new fluorine-based compound is used instead of the nitrogen-containing fluorine-based compound to reduce the content.

An object of the present invention is that even if the content of the fluorine-based compound in the liquid composition is reduced, when it moves along the surface of the base material, an oil-proof coating film is formed on the surface of the base material to cover the surface of the base material. It is an object of the present invention to provide a wet sheet which is made oil-repellent and is useful for preventing oil stains, and a method for forming an oil-proof coating film using the wet sheet.

The first aspect of the present invention is that in a wet sheet in which a sheet base material is impregnated with a liquid composition, the liquid composition contains a hydrophilic oil repellent agent, a film-forming agent, and a solvent, and the hydrophilic oil repellent agent comprises. One or more of the fluorine-based compounds represented by the following formula (1) or formula (2), the film-forming agent is polyacrylic acid, and the solvent is in the range of 1 to 3 carbon atoms. Alcohol and water, and the mass ratio of the fluorine-based compound, the polyacrylic acid, the alcohol, and the water is: Fluorine-based compound: polyacrylic acid: alcohol: water = (0.001 to 0.1) :. (0.1 to 4): (25 to 55): (40 to 75), and the sheet base material has a texture of 30 to 100 g / m ² and a breathability of ¹ to 250 cm ³ / cm ² / sec. It is composed of a non-woven fabric, and contains a fluorine-based compound in the liquid composition at a ratio of 0.01 to 50 mg / m ² per unit area of the non-woven fabric, and water or water and alcohol are combined with the non-woven fabric in a water-equipped state. It is a wet sheet characterized by containing a liquid content at a ratio of 1 to 50 g / m ² .

In the above formulas (1) and (2), p, q and r are integers of 1 to 6 which are the same or different from each other, and may be linear or branched. Further, in the above formulas (1) and (2), X is a hydrocarbon group having 2 to 10 carbon atoms and is selected from an ether bond, a CO-NH bond, an O-CO-NH bond and a sulfonamide bond. It may contain one or more bonds. Further, in the above formulas (1) and (2), Y is a hydrophilic group having a betaine structure.

The second aspect of the present invention is an invention based on the first aspect, wherein the nonwoven fabric is a group composed of polypropylene (PP) fiber, polyethylene terephthalate (PET) fiber, nylon fiber, rayon fiber, pulp fiber and glass fiber. It is a wet sheet made of fibers selected from 1 type or a mixture of 2 or more types, and a plurality of the non-woven fabrics are laminated.

A third aspect of the present invention is a wet sheet based on the first aspect or the second aspect, which moves along the surface of the base material to apply the liquid composition to the surface of the base material, and the applied liquid composition. This is a method for forming an oil-proof coating film, which forms an oil-proof coating film on the surface of the base material by drying an object.

In the wet sheet according to the first aspect of the present invention, the liquid composition impregnated in the sheet base material contains a fluorine-based compound as a hydrophilic oil repellent, polyacrylic acid as a film-forming agent, and alcohol and water as solvents. Is included in a mass ratio of (0.001 to 0.1) :( 0.1 to 4) :( 25 to 55) :: (40 to 75). The fluorine-based compound represented by the above formula (1) or formula (2) is hydrophilic, but is coated on the surface of the base material formed after the wet sheet impregnated with the liquid composition is moved along the surface of the base material. Gives the film oil resistance. It also improves the appearance of the coating film. The film-forming agent can form a good and uniform film even if the content of the fluorine-based compound is reduced. Alcohols having 1 to 3 carbon atoms dissolve fluorine-based compounds to make them water-soluble. Water dilutes the alcohol solution of the fluorine-based compound and suppresses the quick-drying of the coating film caused by alcohol when it is moved along the surface of the substrate with a wet sheet impregnated with the liquid composition, so that the water-based compound solution Improves wettability to the surface of the base material.

In particular, the fluorine-based compound represented by the above formula (1) or formula (2) has a fluorine-containing functional group component unlike the nitrogen-containing fluorine-based compound containing a fluorine-containing functional group component having a perfluoroamine structure shown in Patent Document 1. It is a fluorine-based compound containing a fluorine-containing functional group component having a perfluoroether structure that does not contain nitrogen. When this fluorine-based compound is used, the perfluoro group is difficult to move around the nitrogen atom like the perfluoroamine structure, whereas the ether structure is such that the perfluoro group is easy to move around the oxygen atom. Therefore, when the wet sheet impregnated with the liquid composition containing the fluorine-based compound is moved along the surface of the base material, the film forming property is improved even in the liquid composition containing a small amount of polyacrylic acid. .. Even if oil adheres to the coating film, the fluorine-based compounds that make up the coating film are hydrophilic, so they are easily compatible with water, and when wiped with a cloth soaked in water, the oil-attached coating film is removed. It can be easily removed.

In the wet sheet according to the first aspect of the present invention, since the non-woven fabric of the sheet base material has a predetermined basis weight, the non-woven fabric does not become too thick and its handling is facilitated. Further, when the wet sheet moves along the surface of the base material, the wet sheet has a certain strength without causing tearing or the like. Further, since the non-woven fabric of the sheet base material has a predetermined air permeability, when the liquid composition is brought into contact with the non-woven fabric, the liquid composition surely permeates into the non-woven fabric. By containing a predetermined amount of water or a liquid content of water and alcohol in the non-woven fabric, the liquid composition does not drip from the non-woven fabric by gravity or when the wet sheet is gripped, and the wet sheet is placed along the surface of the base material. The liquid composition can be applied to the surface of the substrate with a uniform thickness when it is moved. Further, since each component is contained in the liquid composition held in the non-woven fabric in a predetermined ratio, the liquid composition spreads well on the surface of the base material with good wettability, and the formed coating film exhibits oil resistance. ..

In the wet sheet of the second aspect of the present invention, the non-woven fabric is one or two selected from the group consisting of polypropylene (PP) fiber, polyethylene terephthalate (PET) fiber, nylon fiber, rayon fiber, pulp fiber and glass fiber. Since it is composed of fibers in which the above are mixed, it has good liquid retention and the liquid composition can be smoothly applied to the surface of the base material. Further, if the non-woven fabric is made into a laminate, the liquid-retaining property of the liquid composition is further enhanced, and even if a large area is applied, the non-woven fabric is less damaged and the durability is excellent.

In the method for forming an oil-proof coating film according to the third aspect of the present invention, the wet sheet moves along the surface of the base material to apply the liquid composition to the surface of the base material, and the applied liquid composition is dried. By doing so, this coating film exhibits oil resistance and has an effect of helping to prevent oil stains on the surface of the base material.

Next, a mode for carrying out the present invention will be described.

[Liquid composition impregnated in sheet base material]
The liquid composition (hereinafter, simply referred to as a liquid composition) impregnated in the sheet base material of the present embodiment is a fluorine-based compound represented by the above formula (1) or formula (2), polyacrylic acid, and 1 carbon atom. It is prepared by mixing one or more alcohols and water in the range of ~ 3. As described above, this fluorine-based compound is used to impart hydrophilic oil repellency to the formed film, and polyacrylic acid is used as a film-forming agent for forming a film with the above liquid composition. Alcohol and water are used to solution fluorine compounds and polyacrylic acid, respectively.

The ratio of the fluorine-based compound, polyacrylic acid, alcohol, and water in the above liquid composition when mixed is (0.001 to 0.1) :( 0.1 to 4) :( 25 to 55) in terms of mass ratio. : (40 to 75), preferably (0.003 to 0.05) :( 0.2 to 3) :( 30 to 53) :( 43 to 69). The characteristic point of this embodiment is that the ratio of the fluorine-based compound 0.001 to 0.1 is less than 0.1 to 10% by mass of the fluorine-based compound described in Patent Document 1, and the amount of the film-forming agent is reduced. The polyacrylic acid is contained in a ratio of 0.1 to 4. As a result, unlike the fluorine-based compound described in Patent Document 1, in the present embodiment, the perfluoro group is mainly contained in the oxygen atom represented by the above formula (1) or formula (2), which does not contain nitrogen in the fluorine-containing functional group component. Since a fluorine-based compound having an ether structure that is easy to move is used, the viscosity of the liquid composition does not decrease so much and the film forming property does not deteriorate even with a small proportion of polyacrylic acid.

If the content of the fluorine-based compound in the above liquid composition is less than the lower limit, the formed film is inferior in hydrophilic oil repellency and cannot form an oil-proof film. If it exceeds the upper limit, the wettability to the substrate to which the liquid composition is applied is poor and the film forming property is poor, which is not economical. Further, after the film formation, the fluorine-based compound becomes powdery and easily peels off, which deteriorates the appearance of the film. In addition, the stability of the liquid composition deteriorates. Since the fluorine-based compound is also hydrophilic as described above, it has a role of easily impregnating the non-woven fabric described later with water.

If the content of polyacrylic acid in the above liquid composition is less than the lower limit, the viscosity of the liquid composition becomes too low and it is difficult to form a film, and the coating film is inferior in oil resistance. When the upper limit is exceeded, the film formed of the above liquid composition is a wet sheet in the drying process in which the solvent volatilizes after the liquid composition is applied when the film thickness is about the wavelength of visible light (100 nm to 800 nm). When the film gradually volatilizes from a thin film portion, iridescent interference fringes are generated on the film, which deteriorates the appearance of the film.

If the alcohol content in the above liquid composition is less than the lower limit, the fluorine-based compound is difficult to dissolve in water and the fluorine-based compound is likely to precipitate. If it exceeds the upper limit, polyacrylic acid is likely to be precipitated, and the drying speed of the coating film when it moves along the surface of the base material on the wet sheet becomes too fast, so that the coating film cannot be formed uniformly. The main purpose of alcohol is to dissolve fluorine-based compounds that are insoluble in water. In addition, when alcohol is contained in the non-woven fabric, it prevents the growth of germs on the non-woven fabric and has a deodorant and antiseptic effect.

If the water content in the above liquid composition is less than the lower limit value, polyacrylic acid is likely to be precipitated, and if it exceeds the upper limit value, the fluorine-based compound is likely to be precipitated. Further, if it is less than the lower limit, the alcohol content becomes large, and the drying speed of the liquid film when it moves along the liquid composition on the wet sheet becomes too fast, and similarly, the film cannot be formed uniformly. When the upper limit is exceeded, the alcohol content decreases and the fluorine-based compound becomes difficult to dissolve. As the water, pure water such as distilled water and ion-exchanged water is preferable.

More specifically, examples of the perfluoroether group in the above formula (1) of the fluorine-based compound in the above liquid composition include perfluoroether groups represented by the following formulas (3) to (7).

More specifically, examples of the perfluoroether group in the above formula (2) of the fluorine-based compound in the above liquid composition include perfluoroether groups represented by the following formulas (8) to (11).

Further, examples of X in the above formula (1) or formula (2) include structures represented by the following formulas (12) to (16). The following formula (12) is an ether bond, the following formula (13) is an ester bond, the following formula (14) is an amide bond, the following formula (15) is a urethane bond, and the following formula (16) is a sulfonamide bond. Is shown.

Here, in the above formulas (12) to (16), R ² and R ³ are hydrocarbon groups having 0 to 10 carbon atoms, and R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. Examples of hydrocarbon groups of R ² and R ³ include alkylene groups such as methylene group and ethylene group, and examples of hydrocarbon groups of R ⁴ include alkyl groups such as methyl group and ethyl group, as well as A phenyl group and the like can also be mentioned.

Further, examples of Y in the above formula (1) or formula (2) include hydrophilic groups having a betaine structure such as a carboxybetaine type, a sulfobetaine type, an amine oxide type, and a phosphobetaine type.

Here, specific examples of the fluorine-based compound having a perfluoroether structure represented by the above formulas (1) and (2) include structures represented by the following formulas (17) to (22). ..

The polyacrylic acid in the above liquid composition contains acrylic acid as the main component of the monomer (preferably 70 mol% or more of acrylic acid, more preferably 90 mol% or more, most preferably substantially 100 mol%). A (co) polymer, specifically, water-soluble polyacrylic acid is exemplified. These polyacrylic acids may be copolymerized with other monomers such as maleic acid and p-styrene sulfonic acid, or may be graft-polymerized with other hydrophilic polymers such as starch and polyvinyl alcohol. This polyacrylic acid is preferably a complete acid type polyacrylic acid having a carboxyl group neutralization rate of 0%, and its weight average molecular weight (GPC-Mw) is 1,000 to 250, converted to polystyrene. The range of 000 is preferable, and the range of 5,000 to 10,000 is more preferable. Of course, a commercially available product may be used as the polyacrylic acid. Commercially available products include, for example, trade names: Aquaric HL-415 (manufactured by Nippon Shokubai Co., Ltd.), Aquaric AS-58 (manufactured by Nippon Shokubai Co., Ltd.), Aquaric DL-40 (manufactured by Nippon Shokubai Co., Ltd.). (Manufactured by the company) and the like.

Examples of the alcohol having a carbon number in the range of 1 to 3 in the above liquid composition include methanol, ethanol, and propanol (n-propanol, isopropanol). When an alcohol having 4 or more carbon atoms is used, the solubility of the above-mentioned fluorine-based compound in alcohol becomes poor. Examples of the water of the present embodiment include pure water such as ion-exchanged water and distilled water, or ultrapure water.

Moreover, the liquid composition of this embodiment may contain a preservative. Examples of preservatives include paraoxybenzoic acid esters, sodium salts of paraoxybenzoic acid esters, benzoic acid, benzoates, dehydroacetic acid, dehydroacetate salts, hinokithiol, phenoxyethanol and the like.

[Method for preparing liquid composition]
The liquid composition of the present embodiment is prepared by weighing a predetermined amount of an aqueous solution of polyacrylic acid, water, and alcohol, mixing them to prepare a mixed solution, and adding a fluorine-based compound to the mixed solution and mixing them. ..

[Composition of wet sheet]
The wet sheet of the present embodiment is formed by impregnating a non-woven fabric as a sheet base material with the above liquid composition. This sheet base material consists of a non-woven fabric having a basis weight of 30 to 100 g / m ² and a breathability of 1 to ²⁰⁰ cm ³ / cm ² / sec. A preferred basis weight is 40-80 g / m ² , and a preferred air permeability is 10-180 cm ³ / cm ² / sec. If the basis weight of this non-woven fabric is less than 30 g / m ² , the strength is insufficient, and the non-woven fabric is easily torn when it moves along the surface of the base material with a wet sheet. If the basis weight exceeds 100 g / m ² , the non-woven fabric becomes too thick and difficult to handle. For the texture of the non-woven fabric, the non-woven fabric is cut into a size of 100 mm × 100 mm, and the mass of the cut non-woven fabric in a moisture equilibrium state (hereinafter, simply referred to as a moisture equilibrium state) at a temperature of 25 ° C. and a humidity of 50% is measured per 1 m ^2. Calculated by converting to the weight of the grain.

Further, when the air permeability of the non-woven fabric is less than 1 cm ³ / cm ² / sec, when the liquid composition is brought into contact with the non-woven fabric, the liquid composition is difficult to permeate into the non-woven fabric and it is difficult to impregnate a predetermined amount of the liquid composition. When the air permeability exceeds 200 cm ³ / cm ² / sec, the liquid composition tends to drip from the non-woven fabric when a predetermined amount of the liquid composition is contained in the non-woven fabric and then by gravity or when the wet sheet is gripped. The air permeability of the non-woven fabric conforms to the "breathability A method (Frazier type method)" of JIS L 1096 "General textile test method" by cutting the non-woven fabric to a size of 100 mm x 100 mm and putting the cut non-woven fabric in a moisture equilibrium state. Then, measure using a non-woven fabric tester.

The water contained in the wet sheet or the liquid content of water and alcohol is 1.0 to 50 g / m ² of the non-woven fabric in a water equilibrium state from the viewpoint of preventing liquid dripping and preventing uneven coating. Is. When the non-woven fabric has a basis weight and air permeability in the above range and contains water or a liquid content of water and alcohol in the above range, the liquid composition does not drip from the non-woven fabric in the wet sheet and is based on the wet sheet. By moving along the surface of the material, the liquid composition can be formed on the surface of the base material to form an oil-proof film having a uniform thickness. Further, the non-woven fabric contains each component in a predetermined ratio at a ratio of 0.1 to 5.0 g / m ² of the fluorine-based compound in the liquid composition per unit area of the non-woven fabric. As a result, the liquid composition spreads on the surface of the base material with good wettability, and the formed coating film exhibits oil resistance.

The non-woven fabric is composed of one or a mixture of two or more selected from the group consisting of polypropylene (PP) fiber, polyethylene terephthalate (PET) fiber, nylon fiber, rayon fiber, pulp fiber and glass fiber. Is preferable. By forming the non-woven fabric from the above fibers, the liquid retention property is good, and the liquid composition can be smoothly applied to the surface of the base material. Further, if a plurality of non-woven fabrics are laminated and sewn together to form a laminated body, the liquid-retaining property of the liquid composition is further enhanced, and even if a large area is applied, the non-woven fabric is less damaged and excellent in durability.

[Wet sheet manufacturing method]
The non-woven fabric, which is the base material of the sheet, is cut into a predetermined size. The liquid composition is then brought into contact with the non-woven fabric. The first method is to immerse a single non-woven fabric or a laminated non-woven fabric (hereinafter, simply referred to as non-woven fabric) in a pad or a wide-mouthed container for a predetermined time, and then liquid. Pull up from the composition and drain. In the second method, a predetermined amount of the liquid composition is sprayed onto a non-woven fabric or the like from a spray nozzle. The liquid content of the liquid composition is contained in the non-woven fabric at a ratio of 1.0 to 50 g / m ² with respect to the non-woven fabric in a water equilibrium state.

As another method, the non-woven fabric after deliquescent or the non-woven fabric after spraying is applied so that the liquid content of the liquid composition is contained in the non-woven fabric at a ratio of 1.0 to 50 g / m ² with respect to the non-woven fabric in the water equilibrium state. Pressurize while sandwiched between the press and the lower press to adjust the liquid content. When the non-woven fabric is a non-woven fabric laminate, the liquid can be uniformly impregnated from the lower non-woven fabric to the upper non-woven fabric by applying pressure. If the non-woven fabric impregnated with the liquid composition is not used immediately, one or more wet sheets may be vapor-deposited with aluminum in a moisturizing container or moisturizer to prevent evaporation of water and volatilization of alcohol. It is preferable to store it in a case.

[Method of forming an oil-proof coating film]
The oil-proof coating film moves along the surface of the base material with the wet sheet to apply the liquid composition to the surface of the base material. Examples of the base material include metal materials, plastic materials, ceramic materials, glass materials, surface-processed wood, and processed paper that require oil-proof treatment. An oil-proof coating film is formed on the surface of the base material by applying the liquid composition applied to the surface of the base material and then allowing it to stand at room temperature for natural drying.

Next, examples of the present invention will be described in detail together with comparative examples.

[13 types of liquid compositions for wet sheets of Examples 1 to 7 and Comparative Examples 1 to 6]
Table 1 shows the composition ratios of the fluorine-based compounds, polyacrylic acid, alcohol, and water in the liquid compositions for wet sheets of Examples 1 to 7 and Comparative Examples 1 to 6. In Examples 1 and 7 and Comparative Examples 1 to 4 and 6, the fluorine-based compound represented by the above-mentioned formula (17) was used, and in Example 2, the fluorine-based compound represented by the above-mentioned formula (18) was used. In Example 3, the fluorine-based compound represented by the above-mentioned formula (19) was used, in Example 4, the fluorine-based compound represented by the above-mentioned formula (20) was used, and in Example 5, the above-mentioned formula (21) was used. ), And in Example 6, the fluorine-based compound represented by the above-mentioned formula (22) was used. In Comparative Example 5, a nitrogen-containing fluorine-based compound represented by the following formula (23) shown in Patent Document 1 was used. In Table 1, the "mixed alcohol" is an industrial alcohol containing 85% by mass of ethanol, 10% by mass of 1-propanol, and 5% by mass of 2-propanol.

<Example 1>
0.11 g (solid content polyacrylic acid 0.05 g) of an aqueous solution of polyacrylic acid having a solid content of 45% by mass (manufactured by Nippon Shokubai Co., Ltd., trade name: Aquaric HL-415, weight average molecular weight 10,000, pH 2) ), 4.85 g of distilled water and 5.0 g of ethanol are weighed, and these are sufficiently mixed, and then 0.04 g of the fluorine-based compound represented by the above formula (17) is added to this mixed solution. The mixture was mixed to prepare a liquid composition.

<Examples 2 to 7 and Comparative Examples 1 to 6>
As shown in Table 1, the type and addition amount of the fluorine-based compound were changed, the type and addition amount of polyacrylic acid were changed, the type and addition amount of alcohol were changed, and the addition amount of water was changed. In the same manner, liquid compositions for each of the wet sheets of Examples 2 to 7 and Comparative Examples 1 to 6 were prepared. In Comparative Example 5, polyacrylic acid was not added.

[20 types of wet sheets of Test Examples 1 to 11 and Comparative Test Examples 1 to 9]
Table 2 shows the details of the treatment after impregnating the liquid composition, the non-woven fabric which is the base material sheet, and the non-woven fabric which constitute the 20 types of wet sheets of Test Examples 1 to 11 and Comparative Test Examples 1 to 9 with the liquid composition. ..

<Test Example 1>
In the wet sheet of Test Example 1, a non-woven fabric (moisture content:) in which PET fibers and pulp fibers having a basis weight of 60 g / m2, a thickness of 0.3 mm, and a breathability of 150 cm ³ / cm ² / sec, which were first cut into 100 mm × 100 mm, were mixed. Less than 0.1%) was prepared. The liquid composition of Example 1 was stored in a pad, and the non-woven fabric was immersed therein for 30 seconds. Then, the non-woven fabric was pulled up from the pad and hung to drain the liquid to obtain the desired product. When the liquid content of the liquid composition was calculated from the mass difference between the mass of the non-woven fabric before liquid impregnation and the mass of the non-woven fabric after liquid impregnation, it was 40 g / m ² , so the content of the fluorine-based compound was determined from the liquid composition. Was calculated to be 8.00 mg / m ² .

<Test Examples 2 to 11 and Comparative Test Examples 1 to 9>
For the wet sheets of Test Examples 2 to 11 and Comparative Test Examples 1 to 9, a base material sheet having the basis weight, air permeability, and material shown in Table 2 was prepared, respectively. As shown in Table 2, the liquid compositions of Examples 1 to 7 and Comparative Examples 1 to 6 were stored in the same pad as in Example 1, and the non-woven fabric was immersed therein for 30 seconds. Then, the non-woven fabric was pulled up from the pad to obtain the desired product. Table 2 shows the results of the liquid content and the amount of fluorine-based compounds.

<Comparative tests and evaluations>
Hold the 20 types of wet sheets of Test Examples 1 to 11 and Comparative Test Examples 1 to 9 in their hands, and put the SUS304 substrate having a thickness of 1 mm, a length of 150 mm, and a width of 70 mm in a vertically standing state, and then the SUS304 substrate. It moved along the entire surface and dried at a temperature of 25 ° C. to form a coating film on the substrate surface. The appearance of the above 20 types of coating films and the oil resistance of the coating film surface immediately after the coating film was formed were investigated. In addition, the amount of oil adhering after moving along the range hood that guides the oil vapor generated during cooking and the cleanability when the oil stains were wiped with a cloth soaked in water were investigated. These results are shown in Table 3.

(1) Appearance of coating film (SUS304 substrate)
By visually observing the obtained coating film, whether or not streaks are generated in the coating film, whether or not iridescent interference fringes are generated throughout the coating film, and whether or not the coating film is powder-blown. I examined. If the coating film does not have streaks, interference fringes or powder blowing, it is regarded as "excellent", and if any of streaks, interference fringes or powder blowing occurs on the coating film, it is regarded as "good". , Those with mottled streaks, interference fringes or powder blowing on the coating film are regarded as "slightly defective", and any of streaks, interference fringes or powder blowing is entirely generated on the coating film. The thing was regarded as "bad".

(2) Water wettability of the coating film surface (water contact angle)
Using Kyowa Interface Science Drop Master DM-700, prepare ion-exchanged water at 22 ° C ± 1 ° C in a syringe, and make 2 μL of droplets ejected from the tip of the syringe needle. Next, the coating film on the SUS304 substrate to be evaluated is brought close to the droplets to adhere the droplets to the coating film. The contact angle of the attached water was measured. The water wettability (hydrophilicity) of the coating film surface was evaluated by using the value obtained by analyzing the contact angle 1 second after the water touches the film surface in a stationary state by the θ / 2 method as the water contact angle.

(3) Oil repellency on the coating film surface (HD contact angle)
Using Kyowa Interface Science Dropmaster DM-700, prepare n-hexadecane (hereinafter referred to as oil) at 22 ° C ± 1 ° C in a syringe, and make 2 μL droplets ejected from the tip of the syringe needle. To do. Next, the coating film on the SUS304 substrate to be evaluated is brought close to the droplets to adhere the droplets to the coating film. The contact angle of the attached oil was measured. The contact angle 1 second after the oil touched the surface of the coating film in a stationary state was analyzed by the θ / 2 method as the contact angle of the oil, and the oil repellency of the coating film surface was evaluated.

(4) Situation of oil stains With 20 types of wet sheets in hand, they were moved along the inner surface of a clean range hood in the kitchen and air-dried at room temperature to form an oil-proof coating film. For comparison, a part was not applied. Oil vapor was generated under the range hood for 0.5 hours every day, and the state of oil adhesion on the inner surface of the range hood after 30 days was visually inspected. The case where the amount of oil adhered was clearly smaller than that of the unapplied portion was defined as "very small amount". The case where the coating film had a sticky feeling was defined as "small amount". The case where the coating film was clearly sticky was defined as "a large amount". The case where the part where the oil adhered and the part where the oil did not adhere was mottled and partly sticky was defined as "a large amount in some parts".

(5) Cleanability of oil stains In (4) above, when the oil stains adhering to the inner surface of the range hood after 30 days are wiped off with a cloth soaked in water, the cleanability of whether or not the oil stains are removed. I examined. When wiped with a cloth soaked in water, if it has the same degree of cleanliness as before the oil stain test, it is judged as "good", and if it feels sticky after cleaning, it is judged as "slightly bad". When it was clearly sticky, it was regarded as "defective".

As is clear from Table 3, in Comparative Test Example 1, the contact angle showed a good value, but since the liquid composition of Comparative Example 1 in which the proportion of polyacrylic acid was too large as 5% by mass was used, it was coated. Interference fringes were generated on the film, and the appearance of the coating film was poor. Further, in Comparative Test Example 2, the contact angle showed a slightly good value, but the liquid composition of Comparative Example 2 in which the proportion of polyacrylic acid was too small, 0.05% by mass, was used, so that the coating film had oil resistance. Inferior to the above, some oil stains remained after wiping with water, and the cleanability was slightly poor.

In Comparative Test Example 3, the contact angle showed a good value, but since the liquid composition of Comparative Example 3 in which the proportion of the fluorine-based compound was too large at 0.11% by mass was used, the film forming property of the liquid composition was used. The coating film was poorly sprayed, and the appearance of the coating film was poor. In Comparative Test Example 4, since the liquid composition of Comparative Example 4 in which the proportion of the fluorine-based compound was too small as 0.0005% by mass was used, the value of the contact angle was poor, and the formed film was inferior in hydrophilicity and oil repellency, and was an oil-proof film. Was not formed, a large amount of oil stains remained after wiping with water, and the cleanability was poor.

In Comparative Test Example 5, a liquid composition in which the fluorine-based compound is a nitrogen-containing fluorine-based compound containing a fluorine-containing functional group component having a perfluoroamine structure and contains 1% by mass of the fluorine-based compound but does not contain polyacrylic acid is used. Since it was used, the value of the contact angle was poor, the film was inferior in hydrophilicity and oil repellency, an oil-proof film could not be formed, a large amount of oil stains remained by wiping with water, and the cleanability was poor.

In Comparative Test Example 6, the contact angle showed a good value, but the liquid composition of Comparative Example 6 in which the proportion of alcohol was too low at 20% by mass and the proportion of water was too high at 79.48% by mass was used. Therefore, the fluorine-based compound was difficult to dissolve in water, powder blowing occurred on the coating film, and the appearance of the coating film was poor. The cleanability was a little poor.

In Comparative Test Example 7, the contact angle showed a good value, but the basis weight of the non-woven fabric was too small, 20 g / m ^2, and the air permeability was too high, 300 cm ³ / cm ² / sec, so that the wet sheet was placed on the substrate surface. When moved along the wet sheet, the wet sheet was torn and the coating film was formed in a mottled manner. The appearance of the coating film was poor, and the cleanability was slightly poor.

In Comparative Test Example 8, the contact angle showed a good value, but the liquid content of the non-woven fabric was too high at 70 g / m ² , so the liquid composition drips from the non-woven fabric and the liquid composition is on the surface of the SUS304 substrate. It was not possible to form an oil-proof film of uniform thickness. As a result, it was not suitable for practical use, the appearance of the coating film was poor, and the cleanability was slightly poor.

In Comparative Test Example 9, the contact angle showed a good value, but the non-woven fabric was thick and hard because the basis weight of the non-woven fabric was too large at 150 g / m ² and the air permeability was too low at 0.5 cm ³ / cm ² / sec. Therefore, the contact with the substrate was poor. As a result, the appearance of the coating film was slightly poor, and the coating film was formed in a mottled manner. The cleanability was a little poor.

On the other hand, in Test Examples 1 to 11, the wet sheet contains a hydrophilic oil-repellent agent of a fluorine-based compound shown in the first aspect of the present invention, a film-forming agent of polyacrylic acid, and a solvent in a predetermined ratio. Since the sheet base material is impregnated with the liquid composition containing the mixture, and the texture amount, air permeability, fluorine compound amount, and liquid content of the non-woven fabric satisfy the requirements of the wet sheet according to the first aspect of the present invention, SUS304 Good results were obtained on the substrate. Further, in a test with a range hood after 30 days, the amount of oil adhered was extremely small as compared with the uncoated portion, and the cleanability was also good. Further, since the fluorine compound of the present invention is also hydrophilic, it is easily compatible with water, and oil stains can be easily removed with a cloth containing water.

The wet sheet impregnated with the liquid composition for a wet sheet of the present invention can be used in factories that use machine oil, kitchens where oil scatters, range hoods in which oil vapors can enter, and other fields that prevent oil stains and oil-stained areas. Used in the field of cleaning.

Claims (3)

In a wet sheet in which the sheet base material is impregnated with the liquid composition,
The liquid composition contains a hydrophilic oil repellent, a film-forming agent, and a solvent.
The hydrophilic oil repellent is a fluorine-based compound represented by the following formula (1) or formula (2), the film-forming agent is polyacrylic acid, and the solvent is in the range of 1 to 3 carbon atoms. One or more alcohols and water,
The mass ratio of the fluorine-based compound, the polyacrylic acid, the alcohol, and the water is: fluorine-based compound: polyacrylic acid: alcohol: water = (0.001 to 0.1) :( 0.1 to 4). : (25-55): (40-75),
The sheet base material comprises a non-woven fabric having a grain size of ³⁰ to 100 g / m ² and a breathability of ¹ to 250 cm ³ / cm ² / sec, and the fluorine-based compound in the liquid composition is 0. wherein a ratio of 01~50mg / m ^2, the wet sheet, characterized in that the liquid component in conjunction with water or water and alcohol to said nonwoven moisture equilibrium in a proportion of 1 to 50 g / m ^2.

In the above formulas (1) and (2), p, q and r are integers of 1 to 6 which are the same or different from each other, and may be linear or branched. Further, in the above formulas (1) and (2), X is a hydrocarbon group having 2 to 10 carbon atoms and is selected from an ether bond, a CO-NH bond, an O-CO-NH bond and a sulfonamide bond. It may contain one or more bonds. Further, in the above formulas (1) and (2), Y is a hydrophilic group having a betaine structure. The non-woven fabric comprises one or a mixture of two or more selected from the group consisting of polypropylene (PP) fiber, polyethylene terephthalate (PET) fiber, nylon fiber, rayon fiber, pulp fiber and glass fiber. The wet sheet according to claim 1, wherein a plurality of sheets are laminated. The wet sheet according to claim 1 or 2 is moved along the surface of the base material to apply the liquid composition to the surface of the base material, and the applied liquid composition is dried to prevent the surface of the base material from being covered. A method for forming an oil-proof coating film.