Method for manufacturing porous body, method for manufacturing cosmetic products, and method for manufacturing nursing products

Abstract

To provide a porous body which is excellent in heat resistance and oil resistance.SOLUTION: A method for producing a porous body removes sugar alcohol and inorganic salt particles from a mixture obtained by mixing a thermoplastic polyurethane resin, the sugar alcohol and the inorganic salt particles at a temperature equal to or higher than a melting point of the sugar alcohol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a porous body, a porous body, a cosmetic product, and a nursing product. [Background technology]

[0002] Patent Document 1 discloses a method for producing a microporous body. In the method, a three-dimensional interconnected pore structure is obtained by extracting and removing polyethylene glycol and sodium sulfate anhydrous from a molded product of a mixture of polystyrene elastomer, polyethylene glycol, and sodium sulfate anhydrous with water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-244514 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the porous body obtained by the method described in Patent Document 1 does not have sufficient heat resistance and oil resistance, making it difficult to use in applications where heat resistance and oil resistance are required.

[0005] The present disclosure has an object to obtain a porous body having excellent heat resistance and oil resistance. The present disclosure can be realized in the following aspects. [Means for solving the problem]

[0006] A method for producing a porous body, comprising the steps of: mixing a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles at a temperature equal to or higher than the melting point of the sugar alcohol; and removing the sugar alcohol and inorganic salt particles from the mixture. [Effects of the Invention]

[0007] According to the present disclosure, a porous body having excellent heat resistance and oil resistance can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram conceptually illustrating the removal of sugar alcohol and inorganic salt particles from a mixture. DETAILED DESCRIPTION OF THE INVENTION

[0009] Here, a preferred example of the present disclosure will be described. A method for producing a porous body, comprising removing the sugar alcohol and inorganic salt particles from a mixture of a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles in a ratio of the thermoplastic polyurethane resin to the total mixture of 12% by volume to 55% by volume. A porous body obtained by the above manufacturing method. A porous body made of thermoplastic polyurethane resin that has an area change rate of 10% or less in the following oil resistance test. <Oil resistance test> The porous body is cut into a piece of 50 mm x 50 mm x 3 mm and immersed in liquid paraffin at 23°C for 24 hours. The area of ​​the 50 mm x 50 mm surface of the porous body after immersion is measured, and the area change rate ΔS% is calculated. When the area after immersion is S, the area change rate ΔS is expressed as follows: ΔS=(|S-2500| / 2500)×100 - A porous body made of thermoplastic polyurethane resin with an elongation rate of 250% or more in a tensile elongation test (JIS K 7161). Porous body with a porosity of 45%-88%. · Cosmetic products with porous bodies. · Nursing products with porous bodies.

[0010] The present disclosure will be described in detail below. In this specification, when a numerical range is indicated using "-", it is intended to include both the lower limit and the upper limit unless otherwise specified. For example, the expression "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less".

[0011] 1. Manufacturing method of porous body (part 1) The method for producing a porous body of this embodiment involves removing the sugar alcohol and inorganic salt particles from a mixture obtained by mixing a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles at a temperature equal to or higher than the melting point of the sugar alcohol.

[0012] (1) Thermoplastic polyurethane resin The thermoplastic polyurethane resin is not particularly limited. The thermoplastic polyurethane resin is preferably a thermoplastic polyurethane elastomer that exhibits meltability at high temperatures and rubber elasticity at low temperatures. Examples of the thermoplastic polyurethane elastomer include a block copolymer having a hard segment block and a soft segment block as repeating units.

[0013] The hard segment block is preferably composed of at least a diisocyanate and a diol. Examples of diisocyanates include 1,6-hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), isophorone diisocyanate (IPDI), xylene diisocyanate (XDI), hydrogenated XDI, tolylene diisocyanate (TDI), triisocyanate, tetramethylxylene diisocyanate (TMXDI), and 1,3,6-hexamethylene triisocyanate.

[0014] Examples of diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, and tripropylene glycol.

[0015] The soft segment block is composed of at least a polyol and a diisocyanate. It is preferable that Examples of the polyol include polyester polyol, polyether polyol, and polycarbonate polyol.

[0016] Examples of polyester polyols include polyester polyols obtained by condensation polymerization of diols and dicarboxylic acids; and polylactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone. Examples of the diols include the diols exemplified above in the description of the hard segment blocks. Examples of dicarboxylic acids include succinic acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid, and isophthalic acid.

[0017] Examples of polyether polyols include polyether polyols obtained by condensation polymerization of dicarboxylic acids and glycols; polyethylene glycol; polypropylene glycol; and polytetramethylene glycol. Examples of the dicarboxylic acid include the dicarboxylic acids exemplified above in the description of the polyester polyol. Examples of glycols include diethylene glycol and propylene oxide adducts.

[0018] Examples of polycarbonate polyols include polycarbonate polyols obtained by reacting diols with carbonates; copolymers of polycaprolactone polyol and polyhexamethylene carbonate; and the like. Examples of the diols include the diols exemplified above in the description of the hard segment blocks. Examples of carbonates include diethylene carbonate and diethyl carbonate.

[0019] As a commercially available polyurethane-based thermoplastic elastomer, for example, the "Elastollan" series (e.g., ET870-11V, NY585, etc.) manufactured by BASF can be used. One type of thermoplastic polyurethane resin may be used alone, or two or more types may be used in combination.

[0020] (2) Sugar alcohols A sugar alcohol is a polyhydric alcohol obtained by reducing the carbonyl group of a sugar to a hydroxyl group. The sugar alcohol is not particularly limited. From the viewpoint of productivity, a sugar alcohol that is highly soluble in water and has heat stability is preferred. The solubility of the sugar alcohol at 40° C. is preferably 20 g / 100 g water or more, more preferably 30 g / 100 g water, and even more preferably 35 g / 100 g water. The upper limit of the solubility of the sugar alcohol is not particularly limited, but is usually 80 g / 100 g water or less. The residual rate of sugar alcohol when heated to 160°C is preferably 80% by mass or more, and more preferably 90% by mass or more. The residual rate can be defined as the amount (% by mass) of sugar alcohol after heating, where the total amount of sugar alcohol before heating is 100% by mass.

[0021] Examples of sugar alcohols include reduced palatinose, sorbitol, glycerol, erythritol, xylitol, mannitol, maltitol, reduced starch saccharification products, and xylitol. The sugar alcohol is preferably reduced palatinose or sorbitol, and more preferably reduced palatinose. One type of sugar alcohol may be used alone, or two or more types may be used in combination.

[0022] Reduced palatinose can be produced by hydrogenating palatinose, which is produced by treating sugar with a transferase. Specifically, reduced palatinose includes a mixture of white, odorless crystals of α-D-glucopyranosyl-1,6-sorbitol (GPS) and α-D-glucopyranosyl-1,6-mannitol (GPM). A more specific example is Palatinit (trade name: manufactured by Shin-Mitsui Sugar Co., Ltd.). For example, the solubility of Palatinit at 40°C is 40g / 100g of water. When heated to 160°C, the residual rate is 96.6%. The melting point of Palatinit is 145°C-150°C. Sorbitol can be produced by reducing glucose. For example, the solubility of sorbitol at 40°C is 70-80g / 100g of water. The melting point of sorbitol is 95°C.

[0023] (3) Inorganic salt particles The inorganic salt particles are not particularly limited, but from the viewpoint of obtaining a stable internal structure, the inorganic salt particles are preferably a substance that is thermally stable even when the thermoplastic polyurethane resin is thermally melted, and a pore-forming material that is soluble in water. As the inorganic salt, metal salts such as sodium chloride, sodium sulfate, sodium carbonate, sodium metasilicate, and sodium tetraborate are preferably used. Sodium chloride is more preferred as the inorganic salt because it is safe, has a stable particle size, and allows for better control of the pore size of the resin porous body. As the inorganic salt particles, one type of inorganic salt particles may be used alone, or two or more types of inorganic salt particles may be used in combination.

[0024] The average particle diameter D50 (50% diameter on a volume basis) of the inorganic salt particles is not particularly limited. The average particle diameter D50 of the inorganic salt particles is preferably 10 μm or more and 200 μm or less, more preferably 5 μm or more and 150 μm or less, and even more preferably 20 μm or more and 135 μm or less. By appropriately setting the average particle diameter D50 of the inorganic salt particles, the pore size can be suitably controlled.

[0025] In addition to the thermoplastic polyurethane resin, sugar alcohol, and inorganic salt particles, the porous body may optionally contain additives such as colorants, fillers, flame retardants, plasticizers, antistatic agents, antioxidants, ultraviolet absorbers, antifungal agents, etc. Even in such cases, the blending ratio of the additives is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total thermoplastic polyurethane resin.

[0026] (4)Mixture The mixture is preferably a mixture of a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles, with the thermoplastic polyurethane resin content being 12% to 55% by volume relative to the total volume. The content of the thermoplastic polyurethane resin is more preferably 15% to 50% by volume, and even more preferably 20% to 40% by volume. If the content is below the lower limit of the above range, the resin content may be too low, potentially making it difficult to maintain an interconnected porous structure. However, if the content is above the lower limit of the above range, the porous structure can be maintained while the molding is performed. If the content is below the upper limit of the above range, the sugar alcohol and inorganic salt particles can be suitably removed, allowing the pores to be suitably interconnected. The mixture may contain a water-soluble polymer compound other than the sugar alcohol, but preferably does not contain other water-soluble polymer compounds (e.g., polyethylene glycol) that may be used to elute the inorganic salt particles.

[0027] The ratio of sugar alcohol to thermoplastic polyurethane resin (sugar alcohol / thermoplastic polyurethane resin, volume ratio) is preferably 28 / 100 to 230 / 100, more preferably 32 / 100 to 180 / 100. The ratio of the inorganic salt particles to the thermoplastic polyurethane resin (inorganic salt particles / thermoplastic polyurethane resin, volume ratio) is preferably 45 / 100 to 600 / 100, more preferably 60 / 100 to 450 / 100. The ratio of sugar alcohol to inorganic salt particles (sugar alcohol / inorganic salt particles, volume ratio) is preferably 35 / 100 to 60 / 100, more preferably 40 / 100 to 55 / 100.

[0028] (5) Manufacturing method The method for producing a porous body of this embodiment includes, for example, a step of mixing a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles to obtain a mixture, a step of molding the mixture to obtain a molded body, a step of immersing the molded body in water at a predetermined temperature to remove the sugar alcohol and inorganic salt particles and obtain a porous body, and a step of drying the porous body.

[0029] In the mixing step, a single-screw or twin-screw extruder, kneader, pressure kneader, co-kneader, Banbury mixer, Henschel mixer, rotor mixer, or other kneading machine is preferably used. The temperature at which the mixture is mixed is equal to or higher than the melting point of the sugar alcohol. The upper limit of the temperature at which the mixture is mixed is not particularly limited, but can be set to, for example, 170°C or lower. Specifically, when reduced palatinose is used as the sugar alcohol, mixing can be performed at a temperature of 140°C or higher and 170°C or lower. The time for mixing the mixture can be set appropriately, and can be, for example, 10 minutes or longer. In the molding step, the mixture is molded into a desired shape by a technique such as extrusion, injection, pressing, rolling, or blowing.

[0030] In the removal step, the molded body is immersed in water at a predetermined temperature to remove the sugar alcohol and inorganic salt particles. The temperature of the water used for immersion can be, for example, 20°C to 80°C. The immersion time can be, for example, 1 hour to 12 hours. Once the sugar alcohol and inorganic salt particles are removed, the areas where the sugar alcohol and inorganic salt particles were previously present become voids, resulting in a porous body. The removal rate of the sugar alcohol and inorganic salt particles is preferably 98% or more, and more preferably approximately 100%. In the drying step, the porous body is dried at a predetermined temperature, which may be, for example, 20°C to 80°C.

[0031] 2. Manufacturing method of porous body (part 2) In the method for producing a porous body of this embodiment, the sugar alcohol and inorganic salt particles are removed from a mixture of a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles, with the thermoplastic polyurethane resin being mixed at a ratio of 12% by volume to 55% by volume relative to the total. In the method for producing a porous body (part 2), the temperature at which the mixture is mixed is arbitrary. Regarding the "thermoplastic polyurethane resin," "sugar alcohol," "inorganic salt particles," "mixture," and "production method," the explanations in the section "method for producing a porous body (part 1)" apply as is, and will be omitted, except that the "temperature at which the mixture is mixed" is arbitrary.

[0032] 3.Porous materials The porous body of the present disclosure can be obtained by the above-mentioned manufacturing method. The present disclosure can also be understood as a porous body made of a thermoplastic polyurethane resin having the following properties.

[0033] The porous body may have a three-dimensional interconnected pore structure. The porosity of the porous body is preferably 45% to 88%, more preferably 50% to 85%, and even more preferably 60% to 80%. The porosity of the porous body can be calculated from the blending ratio (volume %) of the mixture based on the removal rate of the sugar alcohol and inorganic salt particles. When the removal rate of the sugar alcohol and inorganic salt particles is approximately 100%, the porosity of the porous body can be calculated as the ratio of the total volume of the sugar alcohol and the inorganic salt particles to the total volume of the mixture. The porosity of the porous body can be controlled by adjusting the volume of the sugar alcohol and the volume of the inorganic salt particles. Furthermore, by adjusting the blending ratio of the thermoplastic polyurethane resin, the sugar alcohol, and the inorganic salt particles, the removal rate of the sugar alcohol and the inorganic salt particles can be made nearly 100%.

[0034] The porous body preferably has an area change rate of 10% or less in the following oil resistance test. The area change rate is more preferably 5% or less, and even more preferably 3% or less. The lower limit of the area change rate is 0%. <Oil resistance test> The porous body is cut into a size of 50 mm x 50 mm x 3 mm and immersed in liquid paraffin for 24 hours at 23° C. The area of ​​the 50 mm x 50 mm surface of the porous body after immersion is measured and the area change rate (%) is calculated. The area change rate ΔS is calculated by dividing the area after immersion by S (mm 2 ), ΔS=(|S-2500| / 2500)×100 It is expressed as:

[0035] The porous body preferably has an elongation percentage of 250% or more, more preferably 300% or more, in a tensile elongation test (JIS K 7161). There is no particular upper limit to the elongation percentage, but it is usually 500% or less. The porous body preferably has a tensile strength of 0.30 MPa or more and 1.50 MPa or less, more preferably 0.50 MPa or more and 1.20 MPa or less, as measured by a tensile elongation test (JIS K 7161). The measurement is carried out using, for example, a dumbbell No. 2 test piece (JIS K 7161) at a pulling speed of 50 mm / min.

[0036] The porous body preferably has a hardness of 5 or more and 30 or less, more preferably 10 or more and 20 or less, measured in accordance with JIS K 7312 hardness test type C. The measurement is carried out, for example, on a sample having a thickness of 20 mm or more (for example, 20 mm) using an Asker C-type durometer conforming to JIS K 7312.

[0037] The porous body of this embodiment has the above-described properties and excellent heat resistance, and therefore can be used in a variety of applications. The applications of the porous body are not particularly limited. For example, from the viewpoint of oil resistance, the porous body is suitable for cosmetic products such as cosmetic puffs and eye shadow color chips. Furthermore, the porous body is highly safe for the human body because it uses sugar alcohol and sodium chloride, which are also used for food. Therefore, the porous body is suitable for nursing supplies such as baby bottle sponges and artificial nipples, pacifiers, baby toys, and the like.

[0038] 4. Effects of this embodiment The present inventors have investigated porous bodies using thermoplastic polyurethane resins in order to improve the heat resistance and oil resistance of porous bodies. However, porous bodies using thermoplastic polyurethane resins, polyethylene glycol, and inorganic salt particles shrink after drying and are not suitable for practical use. Furthermore, even when using thermoplastic polyurethane resins, sugar alcohols, and inorganic salt particles, it is difficult to sufficiently remove the inorganic salt particles depending on the conditions. Based on these new findings, the present inventors have conducted extensive research and have developed a method for producing a porous body according to the present embodiment.

[0039] According to the method for producing a porous body of the present embodiment, a porous body having excellent heat resistance and oil resistance can be obtained. The reason for this is not clear, but is presumed to be as follows. Note that the present disclosure should not be construed in any way as being limited by the presumed reason. FIG. 1 conceptually illustrates the removal of sugar alcohol 30 and inorganic salt particles 20 from a molded product of mixture 10. By mixing thermoplastic polyurethane resin 11, sugar alcohol 30, and inorganic salt particles 20 at a predetermined temperature or in a predetermined blend ratio, sugar alcohol 30 and thermoplastic polyurethane resin 10 are mixed appropriately. This allows the sugar alcohol 30, a water-soluble polymer compound, to form a path for the inorganic salt particles 20 to leach into thermoplastic polyurethane resin 10. If the water-soluble polymer compound and thermoplastic polyurethane resin are not sufficiently mixed or if they are mixed together, the path for the inorganic salt particles to leach may not be properly formed. In this embodiment, by using a sugar alcohol as the water-soluble polymer compound and mixing the mixture under predetermined conditions, it is believed that a path for the inorganic salt particles 20 to leach into thermoplastic polyurethane resin 11 was formed. As a result, it is presumed that the inorganic salt particles 20 were successfully removed, resulting in a porous body made of thermoplastic polyurethane resin. [Example]

[0040] The present invention will be explained in more detail below with reference to examples.

[0041] 1. Preparation of porous materials Porous bodies of Examples and Comparative Examples were produced using the raw materials shown in Tables 1 and 2. Details of the main raw materials in Tables 1 and 2 are shown below. Thermoplastic polyurethane resin 1: Ether-based thermoplastic polyurethane elastomer, BASF, Elastollan ET870-11V, specific gravity 1.08 Thermoplastic polyurethane resin 2: Ester-based thermoplastic polyurethane elastomer, BASF, Elastollan NY585, specific gravity 1.08 Polyolefin: α-olefin copolymer, manufactured by Mitsui Chemicals, Toughmer A-4090S, specific gravity 0.885 Sodium chloride 1: Nihon Seien Co., Ltd., Salt 90P, average particle size (D50) 90 μm Sodium chloride 2: Naikai Salt Industry Co., Ltd., Nakul UM, average particle size (D50) 50 μm Sodium chloride 3: Naikai Salt Co., Ltd., Nakuru UM-20, average particle size (D50) 20 μm Sodium chloride 4: Tomita Pharmaceutical Co., Ltd., Tomita Salt SB, average particle size (D50) 135 μm Reduced Palatinose: Mitsui Sugar Co., Ltd., Palatinit, specific gravity 1.479, melting point 145℃-150℃ Sorbitol: Sorbitol SG, manufactured by Bussan Food Science Co., Ltd., specific gravity 1.489, melting point 95°C Polyethylene glycol: Sanyo Chemical, PEG20000, specific gravity: 1.2, melting point: 58°C

[0042] The raw materials were mixed in the blending ratios (vol %) shown in Tables 1 and 2. In Tables 1 and 2, blank blending ratios indicate that the raw material was not blended, i.e., 0 vol %.

[0043] In Examples 1-10 and Comparative Example 1, porous bodies were obtained by the following procedure. The raw materials were mixed using a kneader at 50 rpm, 160°C, and 10 minutes. The resulting mixture was press-molded into a size of 100 mm x 150 mm x 3 mm at 160°C and 5 minutes. The resulting molded body was immersed in water at 40°C for 4 hours to elute the sugar alcohol and inorganic salt particles. The resulting porous body was dried at 40°C for 6 hours. In this manner, the porous bodies of the Examples and Comparative Examples were obtained.

[0044] In Comparative Example 2, a porous body was obtained in the same manner as in Examples 1-10 and Comparative Example 1, except that the mixing temperature was 120°C and the press molding temperature was 120°C.

[0045] [Table 1]

[0046] [Table 2]

[0047] 2. Evaluation Method (1) Appearance The presence or absence of shrinkage in the porous body was judged based on the size of the molded body (100 mm x 150 mm x 3 mm). The appearance of the porous body was evaluated according to the following criteria. A: No shrink wrap. B: No shrinkage, but other defects are found. C: With shrink wrap.

[0048] (2) Heat resistance The heat resistance of the porous bodies of Examples 1 to 8 and Comparative Example 2 was evaluated by the following heat resistance test. An evaluation result of "good" is an indicator that the porous body has excellent heat resistance. <Heat resistance test> The porous body is cut into 50 mm x 50 mm x 3 mm pieces and left to stand in a thermostatic chamber at 90°C for 3 hours. After that, the temperature is returned to room temperature, and the state before and after placing in the thermostatic chamber is compared and evaluated according to the following criteria. Good: No change. Poor: Deformed or melted.

[0049] (3) Tensile strength, tensile elongation (elongation), surface C hardness The tensile strength (MPa), tensile elongation (elongation, %), and surface C hardness of the porous bodies of Examples 1 to 8 and Comparative Example 2 were measured by the method described in the embodiment.

[0050] (4) Oil resistance The oil resistance of the porous bodies of Examples 1 to 8 and Comparative Example 2 was evaluated by the oil resistance test described in the embodiment. The closer the area change rate (%) is to 0, the better the oil resistance is.

[0051] (5) Overall evaluation The porous bodies were evaluated according to the following criteria. A: Appearance is A, heat resistance is good, and oil resistance is 10% or less. B: Appearance is B. C: Appearance is C, heat resistance is poor, or oil resistance is greater than 10%.

[0052] 3.Results The results are shown in Tables 1 and 2. In Tables 1 and 2, "-" indicates that the evaluation was not performed. Examples 1-10 were superior in heat resistance and oil resistance to Comparative Example 2. In Comparative Example 1, the size of the porous body was shrunk to 80 mm x 120 mm compared to the size of the molded body of 100 mm x 150 mm, and it was not very practical. The porous bodies of Examples 1-10 had an area change rate of 10% or less in the oil resistance test. The porous body of Example 1-10 had an elongation percentage of 250 or more in a tensile elongation test (JIS K 7161).

[0053] Among Examples 1-10, Examples 1-8 had better appearance than Examples 9 and 10. Incidentally, collapse was observed in the porous body of Example 9, in which the proportion of thermoplastic polyurethane resin was 10% by volume. In Example 10, in which the proportion of thermoplastic polyurethane resin was 60% by volume, some areas were observed that did not become porous. These results suggest that a porous body can be suitably formed by removing the sugar alcohol and inorganic salt particles from a mixture of thermoplastic polyurethane resin, sugar alcohol, and inorganic salt particles in which the proportion of thermoplastic polyurethane resin to the total is 12% by volume to 55% by volume. The porous bodies of Examples 1-8 had porosities of 45% to 88%.

[0054] 4. Effects of the Example According to the above examples, a porous body having excellent heat resistance and oil resistance can be obtained.

[0055] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible.

Claims

1. A method for producing a porous body, comprising the steps of: mixing a thermoplastic polyurethane resin, a sugar alcohol, and inorganic salt particles in a mixture in which the ratio of the thermoplastic polyurethane resin to the total amount is 12% by volume to 55% by volume; and removing the sugar alcohol and the inorganic salt particles from the mixture; The method for producing a porous body, wherein the ratio of the sugar alcohol to the inorganic salt particles in the mixture (sugar alcohol / inorganic salt particles, volume ratio) is 40 / 100 to 55 / 100.

2. A method for producing the porous body according to claim 1, comprising: The method for producing a porous body, wherein the porous body has an area change rate of 10% or less in the following oil resistance test. <Oil resistance test> The porous body is cut into a size of 50 mm x 50 mm x 3 mm and immersed in liquid paraffin at 23°C for 24 hours. The area of ​​the 50 mm x 50 mm surface of the porous body after immersion is measured, and the area change rate ΔS% is calculated. The area change rate ΔS is calculated by dividing the area after immersion by S (mm ２ ) and ΔS=(|S-2500| / 2500)×100 It is expressed as:

3. A method for producing the porous body according to claim 1 or claim 2, comprising: The method for producing a porous body, wherein the porous body has an elongation percentage of 250% or more in a tensile elongation test (JIS K 7161).

4. A method for producing a porous body described in any one of claims 1 to 3, wherein the thermoplastic polyurethane resin is an ester-based thermoplastic polyurethane elastomer.

5. A method for producing a porous body described in any one of claims 1 to 4, wherein the average particle diameter D50 (50% diameter based on volume) of the inorganic salt particles is 50 μm or more and 135 μm or less.

6. A method for producing a porous body described in any one of claims 1 to 5, wherein the sugar alcohol is sorbitol.

7. A step of obtaining a porous body by carrying out the method for producing a porous body according to any one of claims 1 to 6; and obtaining a cosmetic product using the porous body.

8. A step of obtaining a porous body by carrying out the method for producing a porous body according to any one of claims 1 to 6; and a step of obtaining a nursing article using the porous body.

Images