Urethane foam and liquid collection kit

Abstract

To provide urethane foam having excellent performance.SOLUTION: An aspect according to the present invention is urethane foam. In the urethane foam, a liquid-releasing ratio measured by the following measuring method is 50% or more. (Measuring method of liquid-releasing ratio) A test piece of 7.5 mm×7.5 mm×10 mm is prepared. The test piece is immersed into evaluation liquid for 10 seconds, and the mass of the test piece is measured. The test piece is placed into a centrifugal tube with filter, and centrifugation is performed at 100G×3 seconds. The mass of the test piece after centrifugation is measured. The liquid-releasing ratio is calculated according to the following formula: liquid-releasing ratio (%)=[(test piece mass immediately after immersion-test piece mass after separation) / (test piece mass immediately after immersion-test piece mass in drying)]×100.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a urethane foam and a liquid collection kit.

Background Art

[0002] Hydrophilic urethane foam or water-absorbent urethane foam is used in applications where water absorption (such as the amount of water absorbed and the water absorption rate) is required, such as initial wound dressings, cosmetics, incontinence products, wiping materials, and seedling cultivation media.

[0003] It is known that the water absorption of urethane foam can be imparted by using a polyol containing a hydrophilic group such as alkylene oxide as the polyol that is a raw material of the polyurethane foam.

[0004] For example, Patent Document 1 discloses a hydrophilic urethane foam having excellent water absorption, which is obtained by using a polyether polyol having an ethylene oxide content of 50 to 90% as the polyol that is a raw material of the polyurethane foam.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the urethane foam according to the prior art may not have sufficient performance in applications such as liquid collection.

[0007] Therefore, an object of the present invention is to provide a urethane foam having excellent performance.

Means for Solving the Problems

[0008] The inventors have conducted intensive studies and found that the above problems can be solved by a urethane foam having specific properties. That is, the present invention is as follows.

[0009] One form of the present invention is a urethane foam. The urethane foam has a liquid drainage rate of 50% or more as measured by the following measurement method. (Measurement method of liquid drainage rate) Prepare a test piece of 7.5 mm × 7.5 mm × 10 mm. Immerse the test piece in the evaluation liquid for 10 seconds and measure the mass of the test piece. Put the test piece into a centrifuge tube with a filter and perform centrifugation at 100G × 3 seconds. Measure the mass of the test piece after centrifugation. Calculate the liquid drainage rate according to the following formula. Liquid drainage rate (%) = [(mass of the test piece immediately after immersion - mass of the test piece after separation) / (mass of the test piece immediately after immersion - mass of the test piece at the time of drying)] × 100

[0010] The urethane foam preferably has an average cell diameter of 700 to 1500 μm at a thickness T 0.5

[0011] Another form of the present invention is a liquid collection kit including the urethane foam.

Effect of the Invention

[0012] According to the present invention, a urethane foam having excellent performance can be provided.

Mode for Carrying Out the Invention

[0013] In this specification, when an upper limit value and a lower limit value are separately described, a numerical range combining any upper limit value and any lower limit value is regarded as being substantially disclosed.

[0014] In this specification, the content of a certain component in the urethane foam can be read as the content of the certain component in the raw material composition (foam composition) based on the solid content of the raw material composition (foam composition). ​

[0015] In this specification, when a certain compound is described, its isomers are also considered to be described simultaneously.

[0016] In this specification, unless otherwise specified, various measurements are carried out at an environmental temperature of room temperature (25 °C).

[0017] In this specification, the evaluation solution refers to a solution obtained by diluting 8.4 g of sodium chloride and 0.4 g of potassium chloride with distilled water to make 1 L of the solution.

[0018] Hereinafter, the composition / raw materials, manufacturing method, structure, physical properties / characteristics, uses / usage methods of the urethane foam will be described, but the present invention is not limited thereto.

[0019] <<<Composition / Raw Materials>>> The urethane foam according to the present disclosure is obtained by foaming and curing a foam composition containing a urethane prepolymer. Further, the urethane foam may contain other components. Hereinafter, the urethane prepolymer, which is a constituent raw material of the urethane foam, and other components will be described.

[0020] <<Urethane Prepolymer>> The urethane prepolymer is obtained by reacting a polyol and a polyisocyanate. In other words, the urethane prepolymer is a reaction product of a polyol and a polyisocyanate. More specifically, the urethane prepolymer is usually an isocyanate group-terminated urethane prepolymer (isocyanate prepolymer) obtained by subjecting a polyol and a polyisocyanate to a urethane reaction such that the polyisocyanate is in excess.

[0021] <Polyol> The polyol is not particularly limited and can be freely selected in consideration of the desired properties of the polyurethane foam.

[0022] Examples of the polyol include polyester polyol, polycarbonate polyol, polyether polyol, polyester ether polyol, etc., and they can be freely selected in consideration of the properties of the desired polyurethane foam.

[0023] Examples of the polyester polyol include those obtained by the dehydration condensation reaction of aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, or their acid esters or acid anhydrides with ethylene glycol, 1,3 - propylene glycol, 1,2 - propylene glycol, 1,3 - butanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol, 3 - methyl - 1,5 - pentanediol, neopentyl glycol, 1,8 - octanediol, 1,9 - nonanediol, etc., or mixtures thereof; and polylactone diols obtained by ring - opening polymerization of lactone monomers such as ε - caprolactone and methylvalerolactone.

[0024] Examples of the polycarbonate polyol include those obtained by reacting at least one polyhydric alcohol such as ethylene glycol, 1,2 - propylene glycol, 1,3 - propylene glycol, 1,3 - butanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol, 3 - methyl - 1,5 - pentanediol, neopentyl glycol, 1,8 - octanediol, 1,9 - nonanediol, diethylene glycol, etc. with diethylene carbonate, dimethyl carbonate, diethyl carbonate, etc.

[0025] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc., which are obtained by polymerizing cyclic ethers such as ethylene oxide (EO), propylene oxide, and tetrahydrofuran, respectively, and copolymers thereof. In addition, they can also be obtained by polymerizing the above cyclic ethers using polyhydric alcohols such as glycerin and trimethylolethane.

[0026] Examples of polyester ether polyols include those obtained by dehydration condensation reactions of aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid, alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, or acid esters or acid anhydrides thereof, with glycols such as diethylene glycol or propylene oxide adducts, or mixtures thereof.

[0027] The polyols can be used alone or in combination of multiple ones.

[0028] The polyol is preferably a diol and / or a triol.

[0029] The polyol preferably contains a random-type polyether polyol. More specifically, it is preferable that the random-type polyether polyol is contained in an amount of 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more in all the polyols constituting the urethane prepolymer.

[0030] Random polyether polyol contains ethylene oxide. Here, the "random type" of random polyether polyol indicates that it is a random copolymer. That is, random polyether polyol refers to a polyether polyol in which ethylene oxide and propylene oxide are randomly copolymerized. Note that a polyether polyol in which ethylene oxide and propylene oxide are block copolymerized is referred to as a block polyether polyol.

[0031] It is preferable that the proportion of ethylene oxide in one molecule of random polyether polyol (hereinafter sometimes expressed as the EO content rate of random polyether polyol) is 20.0% by mass or more, 25.0% by mass or more, or 30.0% by mass or more. By including a random polyether polyol with an EO content rate in such a range as the polyol, it becomes easier to adjust the EO content rate of the urethane prepolymer, and a urethane foam with excellent hydrophilicity can be obtained.

[0032] Random polyether polyol preferably contains a diol compound and a triol compound.

[0033] It is preferable that the number average molecular weight of the polyol is 200 to 5000, 300 to 4500, or 400 to 4000. In particular, when the number average molecular weight of the random polyether polyol is in such a range, the number average molecular weight of the urethane prepolymer is included in an appropriate range, so a urethane foam having excellent water absorption and the like can be obtained.

[0034] Note that the raw material of the urethane prepolymer may contain a monoalcohol other than the polyol as an alcohol component within a range that does not inhibit the effects of the invention.

[0035] <Polyisocyanate> The polyisocyanate is not particularly limited and can be freely selected in consideration of the characteristics of the desired polyurethane foam.

[0036] The polyisocyanate may be bifunctional or may have three or more functional groups.

[0037] Examples of the bifunctional polyisocyanate include aromatic ones such as 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), hydrogenated MDI, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, polymethylene polyphenyl polyisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylylene diisocyanate (TMXDI), etc. alicyclic ones such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexane diisocyanate, etc. and alkylene ones such as butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, lysine diisocyanate, etc.

[0038] Examples of polyisocyanates having three or more functional groups include 1-methylbenzene-2,4,6-triisocyanate, 1,3,5-trimethylbenzene-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, triphenylmethane-4,4',4''-triisocyanate, polymeric MDI, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, 1,8-diisocyanatomethyloctane, and the like.

[0039] In addition, the polyisocyanate can include these modified products, derivatives, and the like.

[0040] The polyisocyanate can be used alone or in combination of a plurality thereof.

[0041] The polyisocyanate preferably contains an aliphatic isocyanate. More specifically, it is preferable that the aliphatic isocyanate is contained in an amount of 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more in all the polyisocyanates constituting the urethane prepolymer.

[0042] The blending amount of the polyisocyanate can be adjusted so that the average functional group number of the hydroxyl groups of the polyol and the NCO% of the urethane prepolymer are within a desired range. For example, when the total blending amount of the polyol and the polyisocyanate is 100% by mass, the blending amount of the polyisocyanate can be 10 to 40% by mass, or 20 to 35% by mass.

[0043] <<Other components>> Other components include resin components other than urethane prepolymers and known additives. Known additives include, for example, catalysts, surfactants, antioxidants, ultraviolet absorbers, antibacterial agents, and the like. Further, the urethane foam may contain additives (for example, foam stabilizers described later) used in the production of the urethane foam.

[0044] Other components can be 10% by mass or less, 5% by mass or less, or 2% by mass or less, etc., based on the total amount of the urethane foam.

[0045] <<Properties of Urethane Prepolymer>> The average functionality number (isocyanate group number) of the urethane prepolymer is usually 2 or more, preferably more than 2 and less than 3, or preferably 2.2 or more and 2.7 or less.

[0046] The NCO% (isocyanate content) of the urethane prepolymer is preferably 3.0 to 10.0% or 4.0 to 10.0%. By setting the NCO% of the urethane prepolymer within such a range, when the urethane foam is made hydrophilic, it is possible to obtain a urethane foam having an excellent balance in water absorption rate, water absorption amount, etc.

[0047] The NCO% of the urethane prepolymer is measured in accordance with Method A (toluene / dibutylamine, hydrochloric acid method) of JIS K1603-1:2007 "Plastics - Polyurethane Raw Materials - Aromatic Isocyanates - Test Methods - Part 1: Method for Determining the Isocyanate Group Content".

[0048] The viscosity of the urethane prepolymer at 25°C is preferably 1000 to 10000 mPa·s, 2000 to 8000 mPa·s, or 3000 to 6000 mPa·s. By setting it within such a range, a urethane foam having excellent performance can be easily obtained.

[0049] The viscosity of the urethane prepolymer can be changed, for example, by adjusting the molecular weight, average functionality number, etc. of the urethane prepolymer.

[0050] The number average molecular weight of the urethane prepolymer is not particularly limited as long as the effects of the invention are not inhibited. For example, it is preferably 500 to 10,000, 750 to 7,500, or 1,000 to 5,000. By setting the range in this way, the viscosity of the foam composition containing the urethane prepolymer does not become too high, making molding easy, and a urethane foam having excellent water absorption and the like can be obtained.

[0051] The viscosity of the urethane prepolymer at 25°C is the E-type viscosity measured in accordance with JIS Z8803:2011 "Method for Measuring Viscosity of Liquids". The measurement is performed using a cone-plate type rotational viscometer.

[0052] The proportion of alkylene oxide in one molecule of the urethane prepolymer is preferably 20.0 to 55.0% by mass, 25.0 to 55.0% by mass, or 30.00 to 52.5% by mass. More specifically, the proportion of ethylene oxide in one molecule of the urethane prepolymer (hereinafter sometimes referred to as the urethane prepolymer EO content) is preferably 20.0 to 55.0% by mass, 25.0 to 55.0% by mass, or 30.00 to 52.5% by mass. By setting the proportion of alkylene oxide or the urethane prepolymer EO content within such a range, a urethane foam having excellent water absorption and the like can be obtained.

[0053] The proportion of alkylene oxide in one molecule of the urethane prepolymer or the urethane prepolymer EO content indicates the mass percentage of alkylene oxide or ethylene oxide contained in one molecule of the urethane prepolymer when the mass (number average molecular weight) of one molecule of the urethane prepolymer is 100% by mass.

[0054] Here, the urethane prepolymer EO content indicates the mass percentage of ethylene oxide contained in the urethane prepolymer when the total amount of the urethane prepolymer is 100% by mass.

[0055] <<<STRUCTURE>>> <<Apparent porosity>> The urethane foam preferably has an apparent porosity of 10% or more, 12% or more, or 15% or more, and preferably 90% or less, 80% or less, or 70% or less on at least one main surface (preferably both main surfaces). The apparent porosity of the urethane foam is measured as follows.

[0056] (Method for measuring apparent porosity) Using a scanning electron microscope (SEM, Keyence Corporation, VHX-D510), an enlarged image (evaluation area) of the surface of the urethane foam is captured to obtain a surface image. The captured surface image is separated into the resin skeleton part and the void part by color brightness using the attached image processing software, the area of the void part is calculated, and for the parts where the resin skeleton part and the void part cannot be clearly separated by color brightness, manual setting is performed, and the apparent porosity is calculated by the following formula. Apparent porosity (%) = [(Area of void part) / (Evaluation area)] × 100

[0057] The apparent porosity can be adjusted by changing the surface uneven shape (or surface roughness) of the base material (the base material in contact with the urethane foam) used when manufacturing the urethane foam. For example, when using a base material with large surface unevenness (for example, an embossed base material), the apparent porosity tends to be high.

[0058] <<Average cell diameter>> When the thickness of the urethane foam is T, the average cell diameter (cross-sectional average cell diameter) at a thickness of 0.1T from the main surface (one main surface) of the urethane foam (thickness T 0.1 ) is preferably 100 to 1000 μm, or 300 to 800 μm. 0.1 When the thickness of the urethane foam is T, the average cell diameter (cross-sectional average cell diameter) at a thickness of 0.5T from the main surface (one main surface) of the urethane foam (thickness T

[0059] When the thickness of the urethane foam is T, the average cell diameter (cross-sectional average cell diameter) at a thickness of 0.5T from the main surface (one main surface) of the urethane foam (thickness T 0.5 ) is preferably 100 to 1000 μm, or 300 to 800 μm. 0.5The average cell diameter in cross-section is preferably 700 to 1500 μm, or 750 to 1200 μm.

[0060] When the thickness of the urethane foam is T, the average cell diameter at a thickness of 0.9T from the main surface (one of the main surfaces) of the urethane foam (thickness T 0.9 ) is preferably 100 to 1000 μm, or 300 to 800 μm. 0.9 (average cell diameter in cross-section)

[0061] T 0.5 average cell diameter in cross-section / T 0.9 average cell diameter in cross-section, or T 0.5 average cell diameter in cross-section / T 0.1 The average cross-sectional cell diameter is preferably 1.2 or more, 1.4 or more, or 1.6 or more, and is preferably 2.5 or less, 2.3 or less, or 2.1 or less.

[0062] T 0.1 average cell diameter in cross-section, T 0.5 average cell diameter in cross-section, T 0.9 By setting the average cell diameter in cross-section within the range as described above, it becomes easier to obtain a urethane foam having an excellent balance between liquid drainage property and water absorption property.

[0063] T 0.1 average cell diameter in cross-section, T 0.5 average cell diameter in cross-section, T 0.9 The average cell diameter in cross-section can be measured according to the following method.

[0064] (Method for measuring average cell diameter in cross-section) Using a scanning electron microscope (SEM, manufactured by KEYENCE CORPORATION, VHX-D510), enlarged images of each cross-section along a predetermined thickness of the foamed layer are captured, and the average cell diameter (μm) of each cross-section is determined by image analysis. The number of bubbles to be analyzed is 30, and the average value of the longest diameters of each cell is calculated.

[0065] The cell diameter of the urethane foam can be adjusted according to the amount and type of the foaming agent, and the size of the cross-sectional average cell diameter at each thickness can be adjusted by changing the foam stabilizer. For example, when using a foam stabilizer with a higher foaming effect, the cell diameter in the thickness direction tends to be uniform, and T 0.5 the cross-sectional average cell diameter, and T 0.1 the cross-sectional average cell diameter (or T 0.9 the cross-sectional average cell diameter) tend to have close values. In the present disclosure, the HLB can be referred to as an index of the foaming effect. More specifically, in the present disclosure, the foaming effect is likely to be enhanced by using a foam stabilizer with a high HLB. The HLB of the foam stabilizer is preferably 11 to 20, 12 to 19, or 13 to 18. The value of the HLB can be obtained, for example, by the Griffin method.

[0066] <<<Physical properties / Properties>>> <<Drainage rate>> The urethane foam according to the present disclosure preferably has a drainage rate of 50% or more, more preferably 60% or more, as measured by the following measurement method.

[0067] (Measurement method of drainage rate) Prepare a test piece of 7.5 mm × 7.5 mm × 10 mm. Immerse the test piece in the evaluation liquid for 10 seconds and measure the mass of the test piece. Place the test piece in a centrifuge tube with a filter and perform centrifugation at 100G for 3 seconds. Measure the mass of the test piece after centrifugation. Calculate the drainage rate according to the following formula. Drainage rate (%) = [(mass of the test piece immediately after immersion - mass of the test piece after separation) / (mass of the test piece immediately after immersion - mass of the test piece at the time of drying)] × 100

[0068] The larger the surface porosity, and also, T 0.5 the larger the cross-sectional average cell diameter, the more likely the drainage rate is to improve.

[0069] <<Water absorption>> The urethane foam according to the present disclosure preferably has a water absorption of 10 g / g or more, more preferably 15 g / g or more, as measured by the following measurement method.

[0070] (Method for measuring water absorption) Measure according to BS EN 13726-1. Prepare a test piece of 50 mm × 50 mm × 5 mm. Measure the mass of the test piece when dry. Immerse the test piece in an evaluation liquid 40 times its mass at 37°C for 30 minutes. After hanging the immersed test piece for 20 seconds, measure the mass. Calculate the water absorption according to the following formula. Water absorption = [(mass after immersion - mass when dry) / mass when dry]

[0071] <<Water absorption rate>> The urethane foam according to the present disclosure preferably has a water absorption rate measured by the following measurement method of 3 seconds or less, and more preferably 1.5 seconds or less.

[0072] (Method for measuring water absorption rate) Measure according to JIS L 1907. Drop 1 drop of the evaluation liquid at 37°C from a height of 1 cm onto the test piece. The time from when the evaluation liquid is dropped until it is completely absorbed by the test piece is defined as the water absorption rate.

[0073] <<Density>> The density of the urethane foam is, for example, 30 to 150 kg / m 3 or preferably 50 to 120 kg / m 3 The density of the urethane foam can be measured according to JIS K7222:2005 "Foamed Plastics and Rubbers - Method for Determining Apparent Density". Specifically, the density of the urethane foam can be obtained as the value obtained by processing the urethane foam into a size of 100 mm in length × 100 mm in width × 2 mm in thickness and dividing the measured mass by the volume.

[0074] <<<Manufacturing method>>> The urethane foam according to the present disclosure can be manufactured based on known methods. For example, the urethane foam can be obtained by foaming and curing a raw material composition (foam composition) containing a urethane prepolymer and a foaming agent.

[0075] The following describes a preferred method for manufacturing a urethane foam. The method for manufacturing a urethane foam includes a step of manufacturing a urethane prepolymer, a step of preparing a foam composition, and a foaming / curing step.

[0076] <<Manufacture of Urethane Prepolymer>> Into a reaction vessel containing a predetermined amount of polyisocyanate, a predetermined amount of polyol and, if necessary, a catalyst are dropped, and then the inside of the reaction vessel is heated and stirred to react the polyisocyanate with the polyol to produce a urethane prepolymer. The reaction temperature is not particularly limited, but is usually 50 to 120°C, preferably 60 to 100°C. The reaction time is not particularly limited, but is usually 1 to 15 hours.

[0077] The polyol, polyisocyanate, etc. are as described above.

[0078] As the catalyst, known ones used in the manufacture of polyurethane foams can be used. For example, amine-based catalysts, organometallic-based catalysts, etc. can be mentioned.

[0079] Examples of amine-based catalysts include triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, etc.

[0080] Examples of organometallic-based catalysts include stannous octoate, dibutyltin dilaurate, lead octenoate, potassium octylate, etc.

[0081] The catalyst can be used alone or in combination of a plurality.

[0082] When the total amount of the urethane prepolymer is 100 parts by mass, the compounding amount of the catalyst is preferably 0.001 to 5.0 parts by mass.

[0083] <<Preparation of Foam Composition>> Prepare a foam composition containing a urethane prepolymer and a blowing agent. The foam composition may optionally contain a foam stabilizer, a pH adjuster, etc. Further, the foam composition may contain the other components described above.

[0084] The urethane prepolymer and the other components are as described above.

[0085] <Blowing agent> The blowing agent is not particularly limited. Examples of the blowing agent include water, pentane, cyclopentane, methylene chloride, carbon dioxide gas, etc. These can be used alone or in combination of a plurality.

[0086] The blowing agent preferably contains water. When water is used as the blowing agent, carbon dioxide gas is generated during the reaction of the isocyanate groups contained in the prepolymer with water, and the urethane foam is foamed by the carbon dioxide gas.

[0087] When the amount of the urethane prepolymer is 100 parts by mass, the blending amount of the blowing agent is preferably 10 to 40 parts by mass, and more preferably 15 to 30 parts by mass.

[0088] <Foam stabilizer> The foam stabilizer is not particularly limited. Any foam stabilizer can be used as long as it is commonly employed as a raw material for urethane foam. Examples thereof include silicone-based compounds and nonionic surfactants. The foam stabilizer preferably has an alkylene oxide structure (for example, an ethylene oxide structure). Two or more foam stabilizers may be used in combination. As described above, the foam stabilizer preferably includes those having an HLB of 11 to 20, 12 to 19, or 13 to 18.

[0089] When the blending amount of the urethane prepolymer is 100 parts by mass, the blending amount of the foam stabilizer can be 0.1 to 10.0 parts by mass.

[0090] <<Foaming / Curing>> First, stir the foam composition as necessary (stirring step). Next, apply the foam composition onto a substrate (coating step). Thereafter, heat the foam composition as necessary to complete foaming and curing, and produce a urethane foam (reaction step).

[0091] <Stirring step> The stirring step is carried out to uniformly mix each component of the foam composition. When each component in the foam composition is sufficiently homogenized, there is no need to carry out the stirring step.

[0092] The stirring step can be carried out using known stirring means such as a mixer.

[0093] The stirring conditions of the stirring step may be appropriately selected according to the viscosity of the foam composition, the components to be blended, etc.

[0094] <Coating step> In the coating step, the foam composition is applied onto a substrate.

[0095] When manufacturing a urethane foam, if a PET film with a very small surface roughness is used, the bubbles generated from the foam composition tend to stay on the surface of the foam composition covered by the substrate. On the other hand, by using a substrate with a large surface roughness (for example, a substrate provided with surface irregularities by embossing or the like), the bubbles generated from the foam composition are appropriately degassed to the outside of the system. As a result, it becomes possible to obtain a urethane foam with a large surface porosity.

[0096] The material of the substrate is not particularly limited. As the substrate, known ones (paper, silicone release film, PP laminate film, PP laminate paper, etc.) can be used.

[0097] In the coating step, the surface of the foam composition opposite to the surface in contact with the substrate may be further covered with another substrate.

[0098] As coating means, for example, known coating means such as an air knife coater, a blade coater, a knife coater, a roll coater, a cast coater, etc. can be used. The coating conditions (coating speed, etc.) can be appropriately adjusted according to the desired shape of the urethane foam, etc.

[0099] <Reaction process> The reaction process is usually carried out at a temperature of 15 to 120 °C, preferably 15 to 60 °C. The reaction time is usually 1 to 10 minutes.

[0100] Through the above steps, the foam according to the present disclosure is manufactured. For the foam thus obtained, a drying process may be carried out as necessary. The drying process includes, for example, methods of exposing the foam to an environment of 80 to 120 °C using a heating furnace, a microwave oven, high-frequency induction heating, hot air drying, etc. The base material can be removed as appropriate.

[0101] <<<Use / Usage method>>> The use of the urethane foam according to the present disclosure is not particularly limited. The urethane foam according to the present disclosure can be used, for example, as a urethane foam for water absorption (liquid absorption) applications in various applications such as primary wound dressings, cosmetic products, incontinence products, wiping materials, seedling cultivation media, etc. Since the urethane foam according to the present disclosure is particularly excellent in liquid drainage property, it is preferably used as a liquid absorbent when collecting a liquid (for liquid collection). The liquid is, for example, body fluid (such as urine) discharged from humans or animals. As a means for hygienically and efficiently separating these liquids, the urethane foam according to the present disclosure is preferably used. More specifically, the urethane foam according to the present disclosure can be preferably used as a member constituting a liquid collection kit for collecting liquids such as urine. The liquid collection kit contains the urethane foam according to the present disclosure, and it is sufficient that the liquid can be collected by bringing the urethane foam according to the present disclosure into contact with the liquid. The specific configuration, shape, etc. are not limited at all.

[0102] Specific examples of the liquid collection kit are shown below.

[0103] The liquid collection kit has a foam part (liquid absorbing part), a support part, a lid part, and a storage part. The foam part is formed of the urethane foam according to the present disclosure. The shape of the foam part is any shape such as a columnar shape, a block shape, a tube shape, etc. The foam part may be a laminate obtained by laminating a plurality of urethane foams according to the present disclosure, or may be a shape processed by performing punching or the like on the urethane foam according to the present disclosure. The support part has a rod-like structure, and the foam part is assembled near the end part of the support part. The storage part is a closed tubular member having an internal space capable of accommodating the foam part, and an opening part for inserting the foam part and the support part into the internal space. The lid part is formed as a member integral with the support part, and the support part is formed so as to protrude from the lid part. By assembling the storage part and the lid part with the foam part accommodated in the internal space of the storage part, the foam part and the support part are sealed in the storage part, and the foam part and the support part are substantially fixed in a state where they are accommodated in the internal space of the storage part.

[0104] The liquid collection kit is used according to the following procedure. While holding one end (e.g., the lid) of the support part, the foam part assembled near the other end of the support part is brought into contact with the liquid to be collected, so that the foam part absorbs the liquid and holds the liquid. With the liquid held in the foam part, the foam part and the support part are accommodated in the internal space of the storage part, and the lid part is assembled to the storage part, thereby sealing the foam part and preventing the liquid held by the foam part from leaking to the outside. Next, if necessary, the storage part is labeled or enclosed in a predetermined package, and transported to a predetermined location. When performing an analysis of the liquid, the liquid in the foam part is released into the internal space of the storage member using centrifugation or the like, if necessary, with the storage part and the lid part assembled. Next, the lid part, the support part, and the foam part are removed from the storage part, and the liquid in the internal space of the storage part is obtained.

[0105] When a highly water-absorbent urethane foam according to the prior art is used as a water-absorbing body in a liquid collection kit, it has high liquid retention and is difficult to drain in centrifugation. Therefore, it takes time to perform sufficient liquid separation, and the workability may be poor. On the other hand, by using the urethane foam according to the present disclosure as a member of the liquid collection kit, it is possible to appropriately collect the liquid while quickly draining it, and the workability of liquid collection can be improved.

Example

[0106] Hereinafter, the urethane foam will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0107] <<<Manufacture of urethane prepolymer>>> As raw materials, 24.3 parts by mass of polyol I shown below, 24.3 parts by mass of polyol II, 25.8 parts by mass of polyethylene glycol, 25.6 parts by mass of polyisocyanate, and a catalyst to be 20 ppm of the total amount of the composition were weighed into a reaction tank, heated to a temperature range of 55 °C ± 5 °C, and reacted for 4 hours to produce a composition containing a urethane prepolymer. <Polyol I> Random type polyol Copolymer of ethylene oxide / propylene oxide Average functionality 2 Number average molecular weight 1000 EO content 50% by mass Hydroxyl value 112.1 mgKOH / g <Polyol II> Random type polyol Copolymer of ethylene oxide / propylene oxide Average functionality 3 Number average molecular weight 1500 EO content 70% by mass Hydroxyl value 112.1 mgKOH / g <Polyethylene glycol (PEG1000)> Average functionality 2 Number average molecular weight 1000 EO content: 100% by mass Hydroxyl value: 113 mg KOH / g <Polyisocyanate> Hexamethylene diisocyanate (HDI) <Catalyst> KAT 716LA manufactured by TIB Chemical

[0108] The obtained urethane prepolymer had an average functionality of 2.3, an NCO% of 6.2%, a viscosity at 25°C of 4400 mPa·s, and a number-average molecular weight of 4400.

[0109] <<<Manufacture of urethane foam>>> Using the compounding amounts shown in Table 1, the aforementioned urethane prepolymer, blowing agent (water), foam stabilizer [Pluronic (registered trademark) L-64 (HLB: 10), Pluronic (registered trademark) F-68 (HLB: 16), or Pluronic (registered trademark) F-88 (HLB: 16) manufactured by ADEKA], and pH adjuster were mixed to prepare a foam composition. Using a roll coater, the foam composition was cast onto a substrate while adjusting the clearance so that the thickness after foaming would be 5 mm. Further, a substrate was inserted onto the foam composition, and in a state where the foam composition was sandwiched by the substrate, it was foamed and cured at 50 to 60°C. After curing (5 minutes later), the substrate was removed to obtain a sheet-like urethane foam. For each urethane foam in which moisture remained, it was heated in a drying oven at 80°C until it was completely dried.

[0110] <<<Measurement>>> For each urethane foam, density, surface porosity, cross-sectional average cell diameter (T 0.1 Cross-sectional average cell diameter, T 0.5 Cross-sectional average cell diameter and T 0.9 Cross-sectional average cell diameter), water absorption rate, water absorption amount, and liquid drainage rate were measured. The measurement method for each item is as described above. For the test pieces, the aforementioned urethane foam was processed, and the urethane foam was laminated as necessary. The measurement results are shown in Table 1.

[0111] The water absorption rate was evaluated as follows. △: More than 3.0 sec ○: 1.5 sec or more and 3.0 sec or less ◎: Less than 1.5 sec

[0112] The water absorption amount was evaluated as follows. △: 10 g / g or less ○: More than 10 g / g and 15 g / g or less ◎: More than 15 g / g

[0113] The liquid drainage rate was evaluated as follows. △: Less than 50% ○: 50% or more and less than 60% ◎: 60% or more

[0114] Regarding the water absorption rate, water absorption amount, and liquid drainage rate, when all are ◎, the overall evaluation is ◎; when there is no △ and there is at least one ○, the overall evaluation is ○; when there is at least one △, the overall evaluation is △.

[0115]

Table 1

Industrial Applicability

[0116] Since the urethane foam of the present invention has excellent performance, it can be preferably applied to various uses such as initial wound dressings, cosmetic products, incontinence products, wiping materials, seedling cultivation media, etc., and for liquid collection.

Claims

1. A urethane foam having a liquid drainage rate of 50% or more as measured by the following measurement method. (Measurement method of liquid drainage rate) Prepare a test piece of 5 mm × 7.5 mm × 10 mm. Immerse the test piece in the evaluation liquid for 10 seconds and measure the mass of the test piece. Place the test piece in a centrifuge tube with a filter and perform centrifugation at 100 G for 3 seconds. Measure the mass of the test piece after centrifugation. Calculate the liquid drainage rate according to the following formula. Liquid drainage rate (%) = [ (mass of the test piece immediately after immersion - mass of the test piece after separation) / (mass of the test piece immediately after immersion - mass of the test piece at the time of drying) ] × 100

2. Thickness T ０．５ The urethane foam according to claim 1, wherein the average cell diameter at ０．５ is 700 to 1500 µm.

3. A liquid sampling kit comprising the urethane foam according to Claim 1 or 2.

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