Sheet and article

Abstract

To improve an abrasion resistance and shock absorption of a sheet.SOLUTION: A sheet 10 includes a surface layer 11 made of a polyurethane film and a foam layer 12 made of a polyurethane foam. The polyurethane foam has an average cell diameter of 50 μm or more and 300 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a sheet and a method for making the sheet. [Background technology]

[0002] Patent Document 1 discloses a urethane foam molded product that can be used as a floor mat or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-255995 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional polyurethane foam sheets are desired to be improved in terms of abrasion resistance and impact absorption. The present disclosure aims to provide a sheet having high abrasion resistance and impact absorption properties, and a method for manufacturing a sheet having high abrasion resistance and impact absorption properties. The present disclosure can be realized in the following forms. [Means for solving the problem]

[0005] A surface layer made of a polyurethane film; A foam layer made of polyurethane foam, The polyurethane foam has an average cell diameter of 50 μm or more and 300 μm or less.

[0006] A surface layer made of a polyurethane film; A sheet comprising: an installation layer made of polyurethane foam.

[0007] A method for producing the above sheet, comprising the steps of: A sheet manufacturing method comprising: supplying a polyurethane foam raw material to a surface of the polyurethane film traveling in one direction; and reacting and curing the polyurethane foam raw material to form the polyurethane foam. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a sheet having high abrasion resistance and impact absorption properties, and a method for manufacturing a sheet having high abrasion resistance and impact absorption properties. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view of a sheet according to an embodiment. [Diagram 2] 1 is a photograph showing an observed image of a cross section of a sheet. [Diagram 3] 1A to 1C are diagrams for explaining a manufacturing method of a sheet. [Figure 4] FIG. 2 is a cross-sectional view of a polyurethane film with release paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Here, a preferred example of the present disclosure is given.

[0011] The sheet preferably has a Taber abrasion of 250 mg or less on the surface of the skin layer, measured according to JIS K7204 under conditions of an abrasive wheel H-22, a rotation speed of 60 rpm, a load of 250 g, and 1000 revolutions.

[0012] The sheet preferably has a static friction coefficient of the foam layer or the surface facing the placement layer, measured in accordance with JIS K7125, of 0.3 to 10.0 in an atmosphere at a temperature of 23° C. and a relative humidity of 50%.

[0013] The present disclosure will be described in detail below. In this specification, a description using "~" for a numerical range includes the lower limit and the upper limit unless otherwise specified. For example, the description "10 to 20" includes both the lower limit "10" and the upper limit "20". In other words, "10 to 20" has the same meaning as "10 or more and 20 or less".

[0014] Hereinafter, specific embodiments of the present disclosure will be described in detail. The sheet 10 of this embodiment includes a surface layer 11 made of a polyurethane film and a foam layer 12 made of polyurethane foam. In this embodiment, the foam layer 12 corresponds to the installation layer.

[0015] 1. Foam layer 12 The foam layer 12 is made of polyurethane foam. Polyurethane foam can be obtained by reacting a mixed raw material containing polyols and polyisocyanates and foaming it by a mechanical froth method. The mechanical froth method is a method in which bubbles are formed by mixing compressed gas such as an inert gas when stirring and mixing the mixed raw material without adding a specific foaming agent to the mixed raw material.

[0016] As the polyols, it is preferable to use a combination of at least three types of polyols, namely (A) a first polyol made of a polymer polyol, (B) a second polyol made of a polyether polyol, and (C) a third polyol made of a polyester polyol. By using a combination of polyols in this way, it is possible to improve the low compression set and impact absorption resistance of the sheet 10. Furthermore, in a configuration in which the foam layer 12 is an installation layer, it is possible to improve the gripping property of the sheet 10.

[0017] The first polyol is, for example, a polymer polyol having a number average molecular weight of 1500 to 4500 (preferably 2000 to 4000) and a functional group of 3. The first polyol, when used in combination with the second polyol and the third polyol, imparts strength such as tensile strength, and hardness and flexibility according to the application to the polyurethane foam. As the first polyol, for example, a polymer polyol obtained by graft copolymerizing vinyl monomers such as acrylonitrile and styrene in a polyether polyol having a functional group of 3 as a base polyol can be suitably used. As the base polyol, for example, a polyether polyol made of a polymer obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to a trihydric polyhydric alcohol such as glycerin can be mentioned. The number average molecular weight of the first polyol means the number average molecular weight of the base polyol.

[0018] The polymer content of the first polyol (the mass ratio of the portion other than the base polyol to the entire polymer polyol) is preferably 15% by mass to 45% by mass, more preferably 20% by mass to 40% by mass. From the viewpoint of improving the strength of the polyurethane foam, it is preferable that the polymer content of the first polyol is large, but if the polymer content exceeds 45% by mass, the viscosity may become too high and the workability may decrease. The first polyol may contain only one type of polymer polyol, or may contain a combination of two or more types of polymer polyols having different number average molecular weights, polymer contents, etc.

[0019] The content of the first polyol in the mixed raw material is preferably 50 parts by mass to 80 parts by mass, more preferably 55 parts by mass to 78 parts by mass, and even more preferably 58 parts by mass to 70 parts by mass, when the total amount of polyols is 100 parts by mass. If this content is equal to or greater than the lower limit, strength such as tensile strength, hardness, and flexibility can be improved. If this content is equal to or less than the upper limit, strength such as tensile strength and tear strength can be ensured.

[0020] The second polyol is, for example, a polyether polyol having a number average molecular weight of 300 to 900 (preferably 450 to 750) and a functionality of 3. The second polyol, when used in combination with the first polyol, imparts strength such as tensile strength and low compression set to the polyurethane foam, and when used in combination with the third polyol, further improves strength such as tensile strength and low compression set of the polyurethane foam.

[0021] As the second polyol, for example, a polyether polyol consisting of a polymer obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to a trihydric polyalcohol such as glycerin can be suitably used. The second polyol may have a functional group other than a hydroxyl group such as an amino group. As the second polyol, only one type of polyether polyol may be contained, or two or more types of polyether polyols having different number average molecular weights, functional groups, etc. may be contained in combination.

[0022] The content of the second polyol in the mixed raw material is preferably 5 parts by mass to 16 parts by mass when the total amount of polyols is 100 parts by mass. If this content is 5 parts by mass or more, low compression set can be obtained sufficiently. If the content exceeds 16 parts by mass, low resilience is expressed. From the viewpoint of obtaining a polyurethane foam with high resilience, it is preferable to set the content to 16 parts by mass or less. If the content of the second polyol is set to 7 parts by mass to 10 parts by mass, high resilience can be imparted to the polyurethane foam. The content of the second polyol and the content of the third polyol are appropriately adjusted in consideration of the balance between hydrolysis and hardness. The content of the second polyol is not particularly limited, but may be greater than the content of the third polyol.

[0023] The third polyol is, for example, a polyester polyol having a functionality of 2 or 3. The third polyol, when used in combination with the first polyol, imparts heat resistance and chemical resistance to the polyurethane foam, and when used in combination with the second polyol, improves the tensile strength and low compression set of the polyurethane foam. The third polyol also has the effect of making the cells of the polyurethane foam finer and more uniform.

[0024] The molecular weight (number average molecular weight) of the third polyol is preferably in the range of 400 to 2500, more preferably in the range of 450 to 1500. As the third polyol, for example, polycaprolactone-based polyester polyol, adipate-based polyester polyol, etc. can be used. As the polycaprolactone-based polyester polyol, for example, polyester polyol obtained by ring-opening addition polymerization of lactones such as ε-caprolactone can be mentioned. As the adipate-based polyester polyol, for example, polyester polyol obtained by polycondensation of polyfunctional carboxylic acid and polyfunctional hydroxy compound can be mentioned. Among these polyester polyols, it is preferable to use polycaprolactone-based polyester polyol having three functional groups from the viewpoint of making hydrolysis difficult to occur and reducing the content of volatile organic compounds.

[0025] The content of the third polyol in the mixed raw material is preferably 1 to 6 parts by mass, more preferably 2 to 5 parts by mass, when the total amount of polyols is 100 parts by mass. When the content is less than 1 part by mass, low resilience is exhibited. From the viewpoint of obtaining a polyurethane foam with high resilience, it is preferable to set the content to the lower limit or more. Also, when the content is 6 parts by mass or less, an increase in compression set can be suppressed, and low compression set can be ensured.

[0026] The polyols may contain other polyols than the first to third polyols. The other polyols may be any polyol that is generally used in polyurethane foams, without any particular limitations. The polyols may contain an antioxidant to suppress oxidation of the components, but from the viewpoint of reducing the content of volatile organic compounds, it is preferable to use BHT-free polyols that do not use dibutylhydroxytoluene (BHT) as an antioxidant. Examples of BHT-free polyols include polyols that use a hindered phenol-based antioxidant with a molecular weight of 300 or more.

[0027] Polyisocyanates are compounds having a plurality of isocyanate groups. Examples of polyisocyanates include aromatic polyisocyanates such as 4,4-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, and xylylene diisocyanate (XDI), alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), and free isocyanate prepolymers obtained by reacting these with polyols, and modified polyisocyanates such as carbodiimide-modified polyisocyanates. These polyisocyanates may be contained in only one type, or in a combination of two or more types.

[0028] From the viewpoint of reducing the halogen content (especially the chlorine content), it is preferable to use a monomeric isocyanate (e.g., monomeric MDI), a carbodiimide-modified isocyanate, or a prepolymer having an isocyanate group terminal obtained from these as starting materials. The number of functional groups of the polyisocyanates is preferably in the range of 2.0 to 2.2.

[0029] The isocyanate index of the polyisocyanates is preferably in the range of 0.9 to 1.1. The isocyanate index is the equivalent ratio of the isocyanate groups of the polyisocyanates to the reactive groups such as hydroxyl groups in the polyols that can react with isocyanate. Therefore, when the value is less than 1, it means that the reactive groups such as hydroxyl groups are in excess of the isocyanate groups, and when it exceeds 1, it means that the isocyanate groups are in excess of the reactive groups such as hydroxyl groups. If the isocyanate index is 0.9 or more, the polyols can react sufficiently with the polyisocyanates. If the isocyanate index is 1.1 or less, it is preferable from the viewpoint of improving low compression set and high resilience.

[0030] The mixed raw material preferably contains a foam stabilizer. The foam stabilizer is used to smoothly foam the mixed raw material. As the foam stabilizer, a known foam stabilizer that is usually used when the mechanical froth method is adopted, for example, a silicone-based foam stabilizer, can be used. Since such a foam stabilizer has a high viscosity, it is usually diluted with a solvent such as alkylbenzene and then mixed into the mixed raw material. As the solvent, a low-viscosity polyol having a viscosity of 500 cps or less (preferably a viscosity of 40 cps to 500 cps) may be used. Examples of low-viscosity polyols include polyether polyols having a molecular weight (number average molecular weight) of 1700 or less and polyols that are liquid at room temperature.

[0031] The content of the foam stabilizer in the mixed raw material is preferably 3 to 6 parts by mass relative to 100 parts by mass of polyols. If the content is 3 parts by mass or more, the foam stabilizing power is sufficient, and a uniform cell structure can be formed and the density can be reduced. Even if the content exceeds 6 parts by mass, no significant improvement in the foam stabilizing power can be expected. When the foam stabilizer is diluted with a solvent, the mass ratio (foam stabilizer:solvent) is preferably in the range of 25:75 to 75:25.

[0032] The catalyst is mainly for promoting the urethane reaction between the polyols and the polyisocyanates, and the mixed raw material preferably contains a catalyst. As the catalyst, known catalysts usually used in polyurethane foams, such as organometallic compounds such as ferric acetylacetonate, stannous octoate, and tin octoate (tin octoate), tertiary amines such as triethylenediamine, dimethylethanolamine, and N,N',N'-trimethylaminoethylpiperazine, acetates, and alkali metal alcoholates can be used.

[0033] The catalyst content in the mixed raw material is preferably 0.1 to 5.0 parts by mass relative to 100 parts by mass of polyols. If this content is 0.1 parts by mass or more, the urethane reaction can be sufficiently promoted. If the content is 5.0 parts by mass or less, the urethane reaction is prevented from being excessively promoted, and the cell structure can be formed uniformly.

[0034] The crosslinking agent is used to form crosslinks between polyols to improve strength, etc., and the mixed raw material preferably contains a crosslinking agent. Examples of the crosslinking agent include known crosslinking agents that are commonly used in polyurethane foams, such as polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol, amines such as ethylenediamine, diethylenetriamine, hexamethylenediamine, hydrazine, diethyltoluenediamine, and diethylenetriamine, aminoalcohols such as diethanolamine and triethanolamine, and compounds obtained by adding ethylene oxide, polypropylene oxide, etc. to these active hydrogen compounds.

[0035] The content of the crosslinking agent in the mixed raw material is preferably 2.0 parts by mass to 10.0 parts by mass relative to 100 parts by mass of polyols. If the content is 2.0 parts by mass or more, strength such as tensile strength can be ensured. Also, if the content is 10.0 parts by mass or less, appropriate hardness can be obtained and high resilience can be imparted.

[0036] The mixed raw material may contain other components other than those described above as necessary. Examples of the other components include antioxidants, ultraviolet absorbers, thickeners, plasticizers, antibacterial agents, flame retardants, and colorants. Examples of the antioxidant include dibutylhydroxytoluene and hindered phenol-based antioxidants, and from the viewpoint of reducing the content of volatile organic compounds, it is particularly preferable to use hindered phenol-based antioxidants having a molecular weight of 300 or more. Examples of the thickener include calcium carbonate, aluminum hydroxide, and magnesium hydroxide. Examples of the flame retardant include expanded graphite, phosphate esters, melamine resins, and halogen-based flame retardants.

[0037] From the viewpoint of impact resistance and absorption, the polyurethane foam preferably has either an open cell structure or a semi-open cell structure, and more preferably has an open cell structure. The open cell structure and the semi-open cell structure are structures in which the cells have pores, unlike the closed cell structure. The cell structure of the polyurethane foam can be evaluated by measuring the air permeability of the polyurethane foam. The air permeability of the polyurethane foam can be determined, for example, as the air permeability (Gurley air permeability) determined in accordance with the air permeability measurement method B (Gurley type method) specified in JIS L1096:2010. The Gurley air permeability of the polyurethane foam is, for example, 5 seconds / 100 mL or more and 20 seconds / 100 mL or less.

[0038] From the viewpoint of maintaining uniformity of the product, the average cell diameter of the polyurethane foam is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less. The average cell diameter of the polyurethane foam is preferably 50 μm or more. From these viewpoints, the average cell diameter of the polyurethane foam is preferably 50 μm or more and 300 μm or less, more preferably 50 μm or more and 250 μm or less, and even more preferably 50 μm or more and 200 μm or less. The average cell diameter of a polyurethane foam can be calculated by dividing the cumulative cell diameters of cells contacting a 25 mm straight line when the cross section of the polyurethane foam is observed under a scanning electron microscope at a magnification of 200 times by the number of cells. Moreover, from the viewpoint of maintaining the elasticity of the polyurethane foam, the thickness of the cell membrane constituting the cells is preferably 10 μm or less, and more preferably 5 μm or less.

[0039] From the viewpoint of maintaining uniformity of the product, the cell size distribution is preferably within ±50 μm of the average cell size for 70% or more of the cells, more preferably within ±30 μm, and particularly preferably within ±20 μm. The cell size distribution can be calculated based on the cell size when the above-mentioned average cell size is measured.

[0040] From the viewpoint of impact absorption, the shape of the cells is preferably approximately spherical. The shape of the cells can be confirmed by observing a cross section of the polyurethane foam under a microscope. For example, the cells preferably have an average circularity (hereinafter also referred to as average circularity) of 0.6 or more, calculated by the following formula (1): Circularity = 4π((cross-sectional area of ​​cell (mm 2 )) / (perimeter of cell cross section (mm)) 2 (1) The circularity indicates how close the cell cross section is to a perfect circle, with the circularity being closer to 1. The average circularity can be measured, for example, by using image analysis software to measure the bubble perimeter and bubble area of ​​all bubbles within an area of ​​1 mm x 1 mm, calculating the circularity of each, and averaging the results.

[0041] The cell structure, average cell size, cell size distribution, and cell shape of the polyurethane foam can be controlled by adjusting the production conditions in the mechanical froth method, the composition of the mixed raw materials, and the viscosity of the mixed raw materials.

[0042] The thickness of the polyurethane foam is not particularly limited. From the viewpoint of impact resistance and absorption, the thickness of the polyurethane foam is preferably 0.5 mm or more, more preferably 1.0 mm or more, and even more preferably 2.0 mm or more. From the viewpoint of reducing the step with the laying surface, the thickness of the polyurethane foam is preferably 20.0 mm or less, more preferably 10.0 mm or less, and even more preferably 5.0 mm or less. From these viewpoints, the thickness of the polyurethane foam is preferably 0.5 mm or more and 20.0 mm or less, more preferably 1.0 mm or more and 10.0 mm or less, and even more preferably 2.0 mm or more and 5.0 mm or less.

[0043] The specific gravity of the polyurethane foam is not particularly limited. From the viewpoint of hardness, the specific gravity of the polyurethane foam is 0.05 g / cm 3 More than 0.08 g / cm is preferable. 3 More preferably, 0.15 g / cm 3 More preferably, the specific gravity of the polyurethane foam is 0.70 g / cm from the viewpoint of shock absorption. 3 Less than 0.60 g / cm is preferred. 3 Less than 0.50 g / cm is more preferable. 3 From these viewpoints, the specific gravity of the polyurethane foam is preferably 0.05 g / cm or less. 3 More than 0.70g / cm 3 Less than 0.08 g / cm is preferred. 3 More than 0.60g / cm 3 Less than 0.15 g / cm is more preferable.3 More than 0.50g / cm 3 The following is even more preferred:

[0044] 2. Epidermal layer 11 The surface layer 11 is made of a polyurethane film. The polyurethane film can be obtained by reacting a mixed raw material containing polyols and polyisocyanates.

[0045] As the polyol, polyester polyol, polyether polyol, polycarbonate polyol, polymer polyol, and mixtures thereof can be used. Among these, polyester polyol is preferred from the viewpoint of abrasion resistance.

[0046] The polyester polyol can be obtained, for example, by reacting a dicarboxylic acid with a glycol according to a conventional method. Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid, oxycarboxylic acids such as oxybenzoic acid, and ester-forming derivatives thereof. Examples of the glycol component include aliphatic glycols such as ethylene glycol, 1,4-butanediol, diethylene glycol, and triethylene glycol, alicyclic glycols such as 1,4-cyclohexanedimethanol, aromatic diols such as p-xylenediol, and polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These polyester polyols have a linear structure, but they can also be made into branched polyesters by using ester-forming components with a valence of 3 or more.

[0047] The content of polyester polyol in the mixed raw material is preferably 50 parts by mass to 100 parts by mass, more preferably 70 parts by mass to 98 parts by mass, and even more preferably 85 parts by mass to 95 parts by mass, when the total amount of polyols is 100 parts by mass. If the content of polyester polyol is equal to or more than the lower limit, the abrasion resistance is good. If the content of polyester polyol is equal to or less than the upper limit, it is preferable from the viewpoint of physical strength.

[0048] Polyisocyanates are compounds having a plurality of isocyanate groups. Examples of polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate, and aliphatic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

[0049] The polyurethane film may further contain additives such as flame retardants, adhesion promoters, colorants, plasticizers, and combinations thereof. The additives are selected so as not to significantly adversely affect the desired properties of the polyurethane film.

[0050] The thickness of the polyurethane film is not particularly limited. From the viewpoint of abrasion resistance and moldability, the thickness of the polyurethane film is preferably 0.001 mm or more, more preferably 0.002 mm or more, and even more preferably 0.003 mm or more. From the viewpoint of stretchability and cost, the thickness of the polyurethane film is preferably 0.100 mm or less, more preferably 0.050 mm or less, and even more preferably 0.010 mm or less. From these viewpoints, the thickness of the polyurethane film is preferably 0.001 mm or more and 0.100 mm or less, more preferably 0.002 mm or more and 0.050 mm or less, and even more preferably 0.003 mm or more and 0.010 mm or less.

[0051] The specific gravity of the polyurethane film is not particularly limited. From the viewpoint of breathability, the specific gravity of the polyurethane film is 0.8 g / cm. 3 More than 0.9 g / cm is preferable. 3 More preferably, 1.0 g / cm 3 More preferably, the specific gravity of the polyurethane film is 1.5 g / cm from the viewpoint of flexibility. 3 Less than 1.3 g / cm is preferred. 3 Less than 1.2 g / cm is more preferable. 3 From these viewpoints, the specific gravity of the polyurethane film is preferably 0.8 g / cm or less. 3 More than 1.5g / cm 3 Less than 0.9 g / cm is preferred. 3 More than 1.3g / cm 3 Less than 1.0 g / cm is more preferable. 3 More than 1.2g / cm 3 is more preferred.

[0052] The elongation of the polyurethane film is not particularly limited. The elongation of the polyurethane film is preferably 150% or more, more preferably 150% to 500%, and even more preferably 200% to 500%. When the elongation is equal to or more than the lower limit, the film has excellent conformability compared to the case where a general PET film or the like is used. The elongation is a value measured in accordance with JIS K 6251.

[0053] The polyurethane film is preferably a non-foaming polyurethane film. It is more preferable to use a substantially non-porous polyurethane film. The polyurethane film may be produced by a wet method, a dry method, or the like, but the dry method is preferable to obtain a substantially non-porous polyurethane film. Specifically, the polyurethane film is applied to a releasable substrate 13 such as release paper or release film by a normal coating method, for example, a knife coater, a comma coater, a reverse coater, or the like, to form a film. The polyurethane film can be evaluated for its substantially non-porous nature by measuring its air permeability. For example, the polyurethane film may have a Gurley air permeability of more than 10,000 seconds / 100 mL.

[0054] FIG. 4 shows an example of a film 11P with a base material 13 used for a polyurethane film. One surface of this film 11P has an uneven shape 11A. The uneven shape 11A forms, for example, a grained pattern or a geometric pattern. When such a film 11P is used, the uneven shape 11A appears on the surface 10A of the sheet 10 shown in FIG. 1, so that the appearance and feel of the sheet 10 can be improved. The uneven shape 11A can be formed, for example, by transferring a shape given to the base material 13.

[0055] 3. Sheet configuration The sheet 10 is, for example, a laminate in which a surface layer 11 made of ester-based polyurethane and a foam layer 12 made of ether-based polyurethane are laminated. The foam layer 12 and the surface layer 11 are preferably in direct contact with each other and bonded together. The surface layer 11 is exposed on the side opposite to the foam layer 12, forming the front surface 10A of the sheet 10. In this embodiment, the foam layer 12 is exposed on the side opposite to the surface layer 11, forming the back surface 10B of the sheet 10. In the present disclosure, when the foam layer 12 is exposed on the side opposite to the surface layer 11, the foam layer 12 is also referred to as an installation layer.

[0056] The sheet 10 is suitable as a rug (carpet, flooring material). When used as a rug, the sheet 10 is placed on a surface such as a room, a passageway, or the floor of a vehicle with the surface 10A facing up. The configuration of the sheet is not limited to this. For example, unlike this embodiment, the sheet may further include an optional layer such as an anti-slip layer on the opposite side of the foam layer to the skin layer.

[0057] The Taber abrasion of the surface 10A of the sheet 10 facing the skin layer 11 is preferably 250 mg or less, more preferably 200 mg or less, and even more preferably 150 mg or less. A low Taber abrasion is an indicator of high abrasion resistance. The Taber abrasion of the surface 10B of the sheet 10 facing the foam layer 12 is greater than the Taber abrasion of the surface of the sheet 10 facing the skin layer 11, and is, for example, 250 mg or more and 300 mg or less. The Taber abrasion amount is measured in accordance with JIS K7204 under the conditions of an abrasive wheel H-22, a rotation speed of 60 rpm, a load of 250 g, and 1000 revolutions.

[0058] The static friction coefficient of the surface 10B of the sheet 10 facing the foam layer 12 is preferably 0.3 to 10.0, more preferably 0.5 to 7.0, and even more preferably 1.0 to 4.0. A high static friction coefficient is an indicator of high gripping ability. The static friction coefficient is measured in accordance with JIS K7125 at a temperature of 23° C. and a relative humidity of 50%.

[0059] When the foam layer 12 is the installation layer, the foam layer 12 comes into contact with the installation surface. The foam layer 12 has a high static friction coefficient and functions as an anti-slip layer for the installation surface. Therefore, even if there is no adhesive layer or the like between the sheet 10 and the installation surface, the sheet 10 can have a good grip on the installation surface.

[0060] 4. Sheet manufacturing method The sheet is manufactured, for example, by supplying polyurethane foam raw material to the surface of a polyurethane film traveling in one direction, and reacting and curing the polyurethane foam raw material to form the polyurethane foam. The sheet is manufactured by a mechanical froth method. The sheet can be manufactured using a manufacturing apparatus 30.

[0061] The manufacturing apparatus 30 includes a mixing section 31, a roll mechanism 32 including a supply roll 33 and a product recovery roll 34, a discharge nozzle 35, a thickness regulation section 36, and a heating section 38. The mixing section 31 is a section for mixing the raw materials to obtain the polyurethane foam raw material M. The supply roll 33 is a section on which a polyurethane film with a base material 13 is wound, and supplies the polyurethane film by a driving source (not shown). The product recovery roll 34 is a section for winding the sheet 10 into a roll and recovering it. The discharge nozzle 35 is a section for supplying the polyurethane foam raw material M onto the polyurethane film. The thickness regulation section 36 is composed of a doctor knife or the like that controls the thickness of the polyurethane foam raw material M on the polyurethane film. The heating section 38 is composed of a heater or the like that heats the polyurethane foam raw material M on the polyurethane film. Furthermore, the manufacturing apparatus 30 includes a base material recovery roll 39 that peels off the base material 13 from the polyurethane film and recovers it.

[0062] The sheet 10 can be manufactured as follows. First, a polyurethane film with a substrate 13 is continuously supplied from a supply roll 33. While the polyurethane film is being continuously supplied, a polyurethane foam raw material M is supplied from a discharge nozzle 35 to the polyurethane film. The thickness of the supplied polyurethane foam raw material M is adjusted to a predetermined thickness by a thickness regulation unit 36. Next, the polyurethane foam raw material M is heated in a heating unit 38 to react and harden. After the polyurethane foam and the polyurethane film in a laminated state are fixed together, the substrate 13 is peeled off, and the sheet 10 is taken up on a product recovery roll 34.

[0063] The sheet 10 thus obtained can be cut into a predetermined shape and used as a rug (carpet, flooring material). In addition to rugs, the sheet 10 can also be used for coasters, trivets, shoe insoles, car seats, etc.

[0064] Next, the effects of this embodiment will be described. Traditionally, fiber materials and resin foams such as polyethylene foam and EVA have been used for personal use and removable rugs (carpet materials, flooring materials) in the home. Basic functions such as cleanability, easy installation, walkability, and durability are required for rugs. Furthermore, in recent years, especially in homes (facilities) for nursing care and child rearing, there is a demand for rugs with few steps (thin thickness) and excellent shock absorption performance due to issues of barrier-free access and ensuring safety in the event of a fall. Thus, there is an increasing demand for sheets that combine the basic functions of carpets and have high shock absorption properties.

[0065] The sheet 10 of this embodiment includes the surface layer 11 and the foam layer 12, and thus has high abrasion resistance and impact absorption properties. Since the sheet 10 has high shock absorption properties, it can be made thinner to accommodate wheelchairs and walkers needed by people who need care or small children, and the difference in height can be made smaller. Furthermore, it can absorb shock in the event of a fall, ensuring safety. The sheet 10 has high abrasion resistance, so durability can be ensured. For example, when used as a carpet, wear caused by friction associated with wheelchairs, walking, and cleaning can be suppressed, and damage to the sheet 10 can be suppressed. This allows the lifespan of the sheet 10 to be extended.

[0066] The sheet 10 of this embodiment has excellent gripping properties of the foam layer 12, and is therefore easy to install. Specifically, the sheet 10 is not easily slippery on the surface on which it is to be installed, even when the foam layer 12 is simply placed in contact with the surface on which it is to be installed. Therefore, the sheet 10 can be installed directly on the surface on which it is to be installed, without using an adhesive or glue as in the past. Furthermore, when an adhesive or glue is not used, there is no need to use a solvent to remove the adhesive or glue remaining on the surface when the mat is removed.

[0067] In the sheet 10 of the present embodiment, solvents and dirt are unlikely to penetrate into the surface layer 11, and any deposits on the surface layer 11 can be easily wiped off. This makes the sheet 10 easy to clean. In addition, the surface layer 11 has high chemical resistance, which contributes to improving the durability of the sheet 10.

[0068] When the foam layer 12 has high resilience, the feet do not sink too much when walking, and walking is easy. Similarly, when the foam layer 12 has high resilience, the wheels of a wheelchair or walker do not sink too much when running, and running is easy.

[0069] In the manufacturing method of the sheet 10 of the present embodiment, the skin layer 11 and the foam layer 12 are integrally molded, eliminating the need for the time and effort required for bonding the skin layer 11 and the foam layer 12. In addition, since both the skin layer 11 and the foam layer 12 are made of polyurethane resin, adhesive strength is ensured and peeling is unlikely to occur.

[0070] The manufacturing method of the sheet 10 of the present embodiment makes it easy to form the sheet 10 into a long, elongated shape that is long in one direction. Such a sheet 10 can be installed on a large surface area by itself, and is easy to use as a carpet. Moreover, the sheet 10 can be easily cut to a predetermined size to adjust the size.

[0071] Furthermore, in the manufacturing method of the sheet 10 of this embodiment, even when the sheet 10 is wound into a roll, the surface layer 11 is interposed between the foam layer 12 wound earlier and the foam layer 12 wound later. If the foam layer 12 wound earlier and the foam layer 12 wound later come into contact with each other, measures are taken to prevent the foam layers 12 from blocking each other, such as laminating a release paper or applying an ultraviolet (UV) coat to the foam layer 12. In the sheet 10 of this embodiment, the surface layer 11 is interposed between the foam layer 12 wound earlier and the foam layer 12 wound later, so that blocking can be suppressed without laminating a release paper or applying an ultraviolet coat to the foam layer 12. In this way, the surface layer 11 of this embodiment also functions as a layer that suppresses blocking. When the sheet 10 of this embodiment is configured to be wound into a roll, the sheet 10 is easy to manufacture and easy to handle. EXAMPLES

[0072] Next, the above embodiment will be described more specifically with reference to examples and comparative examples. 1. Sheet Preparation First, a polyester polyurethane film (Seiko Kasei, Luxkin U2245) was prepared as the polyurethane film of the example. The thickness of the polyurethane film was 0.004 mm. The specific gravity of the polyurethane film was 1.1 g / cm 3 It was.

[0073] Next, the components of the mixed raw materials used in the polyurethane foams of the Examples and Comparative Examples are shown below. Polymer polyol 1: Polymer polyol having a number average molecular weight of 3,000, a functional group number of 3, and a polymer content of 22% by mass (Asahi Glass Co., Ltd., EXCENOL 914) Polymer polyol 2: Polymer polyol having a number average molecular weight of 3,000, a functional group number of 2, and a polymer content of 20% by mass (Asahi Glass Co., Ltd., EXCENOL913) Polymer polyol 3: Polymer polyol having a number average molecular weight of 3,000, a functional group number of 3, and a polymer content of 40% by mass (manufactured by Sanyo Chemical Industries, Ltd., Sharp Flow FS-7301) Polyether polyol: Polyoxypropylene glyceryl ether having a number average molecular weight of 600 and a functional group of 3 (Sanyo Chemical Industries, Ltd., Sannix GP-600) Polyester polyol: polycaprolactone triol with a molecular weight of 540 and a functional group of 3 (Daicel Chemical Industries, Ltd., Plaxel 305) Crosslinker 1: Dipropylene glycol (Asahi Glass Co., Ltd.) Crosslinker 2: MPO (2-methyl-1,3-propanediol) (manufactured by Dalian Chemical Co., Ltd.) Thickener: Aluminum hydroxide (Sumitomo Chemical Co., Ltd., C-31) Foam stabilizer: Dimethylpolysiloxane and polyether block copolymer (Toray Dow Corning Co., Ltd., SZ-1952 ADDITIVE) Catalyst: Ferric acetylacetonate (Nippon Kagaku Sangyo Co., Ltd., Nursem Ferric) Isocyanate: Polymeric MDI (BASF INOAC Polyurethanes, Formlite 500B)

[0074] [Table 1] The above components were mixed in the proportions shown in Table 1 to obtain mixed raw materials for polyurethane foams of the examples and comparative examples. The symbols (A) to (C) in Tables 1 and 2 indicate compounds corresponding to the components described in the embodiments. The numerical values ​​for each component in Table 1 indicate parts by mass.

[0075] The sheet of the embodiment was produced as follows. First, the mixed raw material was put into a mixing head, and stirred and mixed to become homogeneous while mixing in an inert gas (nitrogen) in the range of 69% by volume to 77% by volume. The mixed raw material was then fed onto the polyurethane film that was continuously fed, and heat cured at 120°C to 200°C. In this way, a sheet was obtained in which a surface layer made of a polyurethane film and a foam layer made of polyurethane foam were laminated.

[0076] The sheet of the comparative example was produced as follows. The foam layer was obtained in the same manner as the foam layer of the example, except that a releasable substrate was used instead of the polyurethane film. After removing the releasable substrate, both sides of the obtained foam layer were UV-coated. The UV coating was performed by applying an acrylic resin and irradiating UV. In this way, a sheet having coating layers on both sides and a foam layer made of polyurethane foam was obtained.

[0077] In the comparative sheet thus obtained, the coating layer is exposed on the opposite side to the skin layer, whereas in the example sheet, the foam layer is exposed on the opposite side to the skin layer. The comparative sheet is UV coated mainly for the purpose of suppressing blocking. In other words, the comparative sheet cannot eliminate the coating layer due to the convenience of production and handling. On the other hand, the example sheet does not have a coating layer, since blocking can be suppressed by the skin layer of polyurethane film.

[0078] 2. Measurement of Mean Cell Diameter For the sheets of the examples, the average cell diameter was measured by the method described in the embodiment. The average cell diameter of the polyurethane foams of the Examples was from 50 μm to 300 μm. Polyurethane foams having such cells have excellent impact absorption properties.

[0079] 3. Observation of the sheet The cross section of the sheet of the example was observed using a microscope, and the observed image of the cross section of the sheet is shown in FIG. When the cross section of the polyurethane film was observed over a 1200 μm area, no holes were observed. Such a polyurethane film has excellent cleaning properties. Furthermore, when the cross section of the polyurethane foam was observed, cells with a roughly spherical shape were observed. The size of the cells was highly uniform. A polyurethane foam having such cells has excellent impact absorption properties.

[0080] 4. Evaluation Next, the obtained sheets of the examples and comparative examples were evaluated under the following conditions for the Taber abrasion amount (mg) of the front surface, the static friction coefficient of the back surface, and the Gurley air permeability (sec / 100 mL). In the examples, the front surface is the surface on the polyurethane film (skin layer) side, and the back surface is the surface on the polyurethane foam (foam layer) side. In the comparative examples, both sides of the polyurethane foam are the front surface and the back surface. The results are shown in Table 2.

[0081] [Amount of surface wear] In accordance with JIS K7204, the measurements were performed using an abrasive wheel H-22, a rotation speed of 60 rpm, a load of 250 g, and 1000 revolutions. Each condition was appropriately specified depending on the material of the sheet. [Static friction coefficient of back surface] The measurement was carried out in accordance with JIS K7125 at a temperature of 23° C. and a relative humidity of 50%. [Garley breathability] The air permeability was measured according to the B method (Gurley method) of the JIS L1096:2010 8.26.2. The compression amount was 50% and the range was 100 mL. In the working examples, the measurement was stopped because the air permeability exceeded 300 seconds / 100 mL, and the results are shown as "-" in Table 2.

[0082] [Table 2]

[0083] As shown in Table 2, the Examples showed less wear on the film surface than the Comparative Examples, and were found to have superior wear resistance. The Examples also showed a greater static friction coefficient on the foam surface than the Comparative Examples, and were found to have superior grip. Furthermore, the Examples showed almost no breathability, suggesting superior cleaning properties.

[0084] 5. Effects of the embodiment According to the above-described embodiments, a sheet having high abrasion resistance and impact absorbing properties, and a method for manufacturing a sheet having high abrasion resistance and impact absorbing properties can be provided.

[0085] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the claims of the present disclosure. [Explanation of symbols]

[0086] 10 ... sheet 10A: Surface (surface facing the epidermis layer) 10B: Back side (foam layer side) 11...Epidermal layer 11A…Uneven shape 11P...Film 12 ... Foam layer 13...Base material 30...manufacturing equipment 31...Mixing section 32 ...Roll mechanism 33 ... Supply roll 34 ... Product collection roll 35 ...Discharge nozzle 36 ... Thickness regulation section 38...Heating part 39 ... Substrate recovery roll

Claims

1. A surface layer made of a polyurethane film; A foam layer made of polyurethane foam, The polyurethane foam has an average cell diameter of 50 μm or more and 300 μm or less.

2. A surface layer made of a polyurethane film; A sheet comprising: an installation layer made of polyurethane foam.

3. 3. The sheet according to claim 1, wherein the Taber abrasion amount of the surface on the skin layer side is 250 mg or less, as measured in accordance with JIS K7204 under conditions of an abrasion wheel H-22, a rotation speed of 60 rpm, a load of 250 g, and a rotation number of 1000.

4. The sheet according to any one of claims 1 to 3, wherein the static friction coefficient of the foam layer or the surface of the installation layer side measured in accordance with JIS K7125 is 0.3 to 10.0 in an atmosphere at a temperature of 23°C and a relative humidity of 50%.

5. A method for producing the sheet according to any one of claims 1 to 4, comprising the steps of: A sheet manufacturing method comprising: supplying a polyurethane foam raw material to a surface of the polyurethane film traveling in one direction; and reacting and curing the polyurethane foam raw material to form the polyurethane foam.

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