Sheet and article

Abstract

To provide a sheet that has excellent basic performance and achieves improvements in the abrasion resistance of the front face and the non-slipperiness of the back face.SOLUTION: A sheet 10 comprises: a first film layer 11 including a first polyurethane film; a foamed layer 12 including polyurethane foam; and a second film layer 13 including a second polyurethane film, in the stated order. The average cell diameter of the polyurethane foam is 50-300 μm inclusive.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a sheet and a method for manufacturing the sheet.

Background Art

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

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional sheets using polyurethane foam are desired to be improved in terms of surface wear resistance and non-slip property on the back surface. In addition, it is also desired that the sheet improves basic performances such as shock absorbency and flame retardancy according to the installation purpose, installation location, and the like. An object of the present disclosure is to provide a sheet having excellent basic performances, improved surface wear resistance and non-slip property on the back surface, and a method for manufacturing the sheet having excellent basic performances, improved surface wear resistance and non-slip property on the back surface. The present disclosure can be realized in the following forms.

Means for Solving the Problems

[0005] A first film layer composed of a first polyurethane film, A foamed layer composed of polyurethane foam, A second film layer composed of a second polyurethane film, provided in this order, A sheet, wherein an average cell diameter of the polyurethane foam is 50 μm or more and 300 μm or less.

[0006] The above method for manufacturing a sheet, comprising: Supplying a polyurethane foam raw material between the first polyurethane film and the second polyurethane film that travel in one direction, and reacting and curing the polyurethane foam raw material to form the polyurethane foam, a method for manufacturing a sheet.

[0007] A first film layer composed of a first polyurethane film, A foam layer composed of a polyurethane foam containing a flame retardant, A second film layer composed of a second polyurethane film, provided in this order.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a sheet excellent in basic performance, with improved surface abrasion resistance and back surface slipperiness, and a method for manufacturing a sheet excellent in basic performance, with improved surface abrasion resistance and back surface slipperiness.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

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

[0011] The sheet, wherein the polyurethane foam contains a flame retardant.

[0012] The sheet, wherein the second film layer has a contact surface on the side opposite to the foam layer side that contacts the object to be installed, and the contact surface has an uneven shape.

[0013] A sheet in which the coefficient of static friction of the surface on the second film layer side, measured in accordance with JIS K7125, is 0.3 or more and 10.0 or less in an atmosphere of 23°C and 50% relative humidity.

[0014] A method for manufacturing a sheet, in which the polyurethane foam raw material is heated, reacted, and cured in a posture where the second polyurethane film is located on the upper side with respect to the supplied polyurethane foam raw material to form the polyurethane foam.

[0015] Hereinafter, the present disclosure will be described in detail. In this specification, in the description using "~" for a numerical range, unless otherwise specified, the lower limit value and the upper limit value are included. For example, in the description of "10~20", both the lower limit value "10" and the upper limit value "20" are included. That is, "10~20" has the same meaning as "10 or more and 20 or less".

[0016] Hereinafter, embodiments embodying the present disclosure will be described in detail. The sheet 10 of the present embodiment includes, in this order, a first film layer 11 composed of a first polyurethane film, a foam layer 12 composed of a polyurethane foam, and a second film layer 13 composed of a second polyurethane film.

[0017] 1. Foam layer 12 The foam layer 12 is composed of a polyurethane foam. The polyurethane foam can be obtained by reacting a mixed raw material containing polyols and polyisocyanates and foaming it by the mechanical froth method. The mechanical froth method is a method of forming bubbles by mixing a 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.

[0018] As polyols, it is preferable to use in combination at least three types of polyols: (A) a first polyol composed of a polymer polyol, (B) a second polyol composed of a polyether polyol, and (C) a third polyol composed of a polyester polyol. By using polyols in combination in this way, the low compression residual strain property and impact absorption property of the sheet 10 can be improved.

[0019] The first polyol is, for example, a polymer polyol having a number average molecular weight of 1,500 to 4,500 (preferably 2,000 to 4,000) and a functionality of 3 or 2. The first polyol imparts strength such as tensile strength, hardness according to the application, and flexibility to the polyurethane foam when used in combination with the second polyol and the third polyol. 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 functionality of 3 as a base polyol can be preferably used. Examples of the base polyol include polyether polyols composed of polymers obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to trivalent polyhydric alcohols such as glycerin. In the case of a polymer polyol having a functionality of 2, as the base polyol, for example, a polyether polyol composed of a polymer obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to divalent polyhydric alcohols such as glycol may be used. Note that the number average molecular weight of the first polyol means the number average molecular weight of the base polyol.

[0020] Further, the polymer content of the first polyol (mass ratio of the portion other than the base polyol to the whole 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 larger. However, if the polymer content exceeds 45% by mass, the viscosity may become too high and the workability may deteriorate. Note that as the first polyol, only one kind of polymer polyol may be contained, or two or more kinds of polymer polyols having different number average molecular weights, polymer contents, etc. may be combined and contained.

[0021] When the total amount of polyols is 100 parts by mass, the content of the first polyol in the mixed raw materials is preferably 80 parts by mass to 95 parts by mass, more preferably 85 parts by mass to 90 parts by mass. If this content is at least the lower limit value, the strength such as tensile strength, hardness, and flexibility can be improved. If this content is at most the upper limit value, the strength in tensile strength, tear strength, etc. can be ensured.

[0022] 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 imparts strength such as tensile strength and low compression residual strain property to the polyurethane foam when used in combination with the first polyol, and further improves the strength such as tensile strength and low compression residual strain property of the polyurethane foam when used in combination with the third polyol.

[0023] As the second polyol, for example, a polyether polyol composed of a polymer obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to a trivalent polyhydric alcohol such as glycerin can be preferably used. Further, the second polyol may have a functional group other than a hydroxyl group such as an amino group. And, as the second polyol, only one kind of polyether polyol may be contained, or two or more kinds of polyether polyols having different number average molecular weights, functional groups, etc. may be combined and contained.

[0024] When the total amount of polyols is 100 parts by mass, the content of the second polyol in the mixed raw material is preferably 5 to 15 parts by mass. If this content is at least the lower limit, sufficient low compression residual strain properties can be obtained. Also, if the above content exceeds the upper limit, low resilience is exhibited. From the viewpoint of obtaining a high resilience polyurethane foam, it is preferable to make the above content not exceed the upper limit. Further, when the content of the second polyol is 5 to 15 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 of hydrolyzability and hardness. The content of the second polyol is not particularly limited, but it may be more than the content of the third polyol.

[0025] The third polyol is, for example, a polyester polyol having 2 or 3 functional groups. The third polyol imparts heat resistance and chemical resistance to the polyurethane foam when used in combination with the first polyol, and improves the tensile strength and low compression residual strain properties of the polyurethane foam when used in combination with the second polyol. Further, the third polyol also has the effect of making the cells of the polyurethane foam finer and more uniform.

[0026] 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, polycarbonate-based polyol, etc. can be used. As the polycaprolactone-based polyester polyol, for example, polyester polyols obtained by ring-opening addition polymerization of lactones such as ε-caprolactone can be mentioned. As the adipate-based polyester polyol, for example, polyester polyols obtained by polycondensation of polyfunctional carboxylic acids and polyfunctional hydroxy compounds can be mentioned. Among these polyester polyols, it is preferable to use a polycaprolactone-based polyester polyol with a functionality of 3 from the viewpoints of making hydrolysis less likely to occur and reducing the volatile organic compound content.

[0027] When the total amount of polyols is 100 parts by mass, the content of the third polyol in the mixed raw materials is preferably 1 to 6 parts by mass, more preferably 2 to 5 parts by mass. When this content is less than 1 part by mass, low resilience is exhibited. From the viewpoint of obtaining a high-resilience polyurethane foam, it is preferable to set the above content to be equal to or higher than the lower limit value. Also, if the above content is 6 parts by mass or less, an increase in compression residual strain can be suppressed, and low compression residual strain properties can be ensured.

[0028] In addition, the polyols may contain other polyols other than the above first to third polyols. As the other polyols, any polyols generally used in polyurethane foams can be used without particular limitation. Note that antioxidants may be blended in the above polyols to suppress oxidation of the components, but from the viewpoint of reducing the volatile organic compound content, it is preferable to use BHT-free polyols that do not use dibutylhydroxytoluene (BHT) as an antioxidant. Examples of BHT-free polyols include polyols using hindered phenol-based antioxidants with a molecular weight of 300 or more.

[0029] 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, xylylene diisocyanate (XDI), etc., alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate, etc., aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), etc., or modified polyisocyanates such as free isocyanate prepolymers obtained by the reaction of these with polyols, carbodiimide-modified polyisocyanates, etc. These polyisocyanates may contain only one kind, or two or more kinds may be combined and contained.

[0030] In addition, from the viewpoint of reducing the halogen content (especially chlorine content), it is preferable to use monomeric isocyanate (for example, monomeric MDI), carbodiimide-modified isocyanate, or a prepolymer having an isocyanate group terminal obtained from these as starting materials for polyisocyanates. Also, the functionality of polyisocyanates is preferably in the range of 2.0 to 2.2.

[0031] In addition, the isocyanate index of polyisocyanates is preferably in the range of 0.9 to 1.1. The isocyanate index is the equivalent ratio of the isocyanate groups of polyisocyanates to the reactive groups such as hydroxyl groups that can react with isocyanates in polyols. 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 viewpoints of improving low compression residual strain properties and high resilience.

[0032] The mixed raw material preferably contains a flame retardant. Examples of the flame retardant include expanded graphite, phosphorus-based flame retardants, melamine-based flame retardants, and halogen-based flame retardants. The flame retardant is preferably a non-halogen-based flame retardant in that it does not use environmentally harmful substances, and more preferably one or more selected from the group consisting of expanded graphite and phosphorus-based flame retardants. The flame retardant may be used alone or in combination of two or more.

[0033] From the viewpoint of suppressing bleed and bloom, it is preferable to use expanded graphite as the flame retardant. Expanded graphite is obtained by inserting (intercalating) a chemical substance between the layers of flaky graphite. Examples of the chemical substance to be inserted include nitric acid, potassium permanganate, sulfuric acid, etc. Among these, sulfuric acid having a high expansion start temperature is preferable. The expansion start temperature of the expanded graphite is preferably 170 °C or higher from the viewpoint of suppressing expansion during the production of the sheet 10. Incidentally, the expansion start temperature of the expanded graphite is usually 200 °C or lower.

[0034] The content of the expanded graphite is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 20 parts by mass or more and 45 parts by mass or less, and still more preferably 25 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the polyols. If the content of the expanded graphite is above the lower limit, the flame retardancy can be improved. If the content of the expanded graphite is below the upper limit, it is preferable from the viewpoint of the foamability of the polyurethane foam.

[0035] From the perspective of improving the flame retardancy while ensuring the physical properties of the polyurethane foam, it is preferable to use expanded graphite and a phosphorus-based flame retardant in combination. Examples of the phosphorus-based flame retardant include ammonium polyphosphate, phosphate ester, melamine phosphate, melamine polyphosphate, guanidine phosphate, ethylenediamine phosphate, compounds such as triphenyl phosphate, tricresyl phosphate, bis(1,3-phenylenediphenyl) phosphate, compounds such as triaryl phosphate, trialkyl phosphate, alkylaryl phosphate, and red phosphorus. The phosphorus-based flame retardant used in combination with expanded graphite is preferably a solid (powder) phosphorus-based flame retardant, and more preferably ammonium polyphosphate powder, from the perspective of suppressing bleed and bloom.

[0036] The content of the phosphorus-based flame retardant is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 20 parts by mass or more and 45 parts by mass or less, and still more preferably 25 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of the polyols. If the content of the phosphorus-based flame retardant is above the lower limit, the flame retardancy can be improved. If the content of the phosphorus-based flame retardant is below the upper limit, it is preferable from the perspective of the foaming property of the polyurethane foam. The mass ratio of expanded graphite to the phosphorus-based flame retardant (expanded graphite: phosphorus-based flame retardant) is preferably 5:1 to 1:5, and more preferably 2:1 to 1:2.

[0037] The mixed raw materials preferably contain a foam stabilizer. The foam stabilizer is used to smoothly foam the mixed raw materials. As the foam stabilizer, a known foam stabilizer usually used when the mechanical froth method is adopted can be used, for example, a silicone-based foam stabilizer. Since such a foam stabilizer has a high viscosity, it is usually blended into the mixed raw materials in a diluted state with a solvent such as alkylbenzene. A low-viscosity polyol having a viscosity of 500 cps or less (preferably a viscosity of 40 cps to 500 cps) can be used as the above solvent. Examples of the low-viscosity polyol include polyether polyol having a molecular weight (number average molecular weight) of 1700 or less and polyol that is liquid at room temperature.

[0038] The content of the foam stabilizer in the mixed raw materials is preferably 3 to 15 parts by mass with respect to 100 parts by mass of the polyols. If the content is 3 parts by mass or more, sufficient foaming power can be obtained, and a uniform cell structure can be formed and the density can be reduced. Also, even if the content exceeds 15 parts by mass, no significant improvement in foaming power can be expected. When diluting the foam stabilizer with a solvent, the mass ratio (foam stabilizer: solvent) is preferably in the range of 15:85 to 85:15.

[0039] The catalyst is mainly for promoting the urethanization reaction between polyols and polyisocyanates, and the mixed raw materials preferably contain a catalyst. As the catalyst, known catalysts commonly used in polyurethane foams, such as organometallic compounds such as ferric acetylacetonate, stannous octoate, tin octoate, and metal complex catalysts such as zinc amine catalysts, tertiary amines such as triethylenediamine, dimethylethanolamine, N,N´,N´-trimethylaminoethylpiperazine, acetates, and alkali metal alcoholates can be used. The catalyst may be used alone or in combination of two or more. Among these, it is particularly preferable that ferric acetylacetonate is at least contained because of its stability, good catalytic activity, and non-toxicity. The effect is disclosed, for example, in U.S. Patent No. 5,733,945 and the like.

[0040] The content of the catalyst in the mixed raw materials is preferably 0.1 to 12.0 parts by mass with respect to 100 parts by mass of the polyols. If the content is 0.1 parts by mass or more, the urethanization reaction can be sufficiently promoted. If the above content is 12.0 parts by mass or less, excessive promotion of the urethanization reaction can be suppressed, the formation of the cell structure can be made uniform, and the physical properties can be stabilized.

[0041] The crosslinking agent is used to form crosslinks between polyols to improve strength and the like, and the mixed raw material preferably contains a crosslinking agent. As the crosslinking agent, known crosslinking agents commonly used in polyurethane foams, for example, polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, etc., amines such as ethylenediamine, diethylenetriamine, hexamethylenediamine, hydrazine, diethyltoluenediamine, diethylenetriamine, etc., amino alcohols such as diethanolamine, triethanolamine, etc., and compounds obtained by adding ethylene oxide, polypropylene oxide, etc. to these active hydrogen compounds can be mentioned. The crosslinking agent may be used alone or in combination of two or more.

[0042] The content of the crosslinking agent in the mixed raw material is preferably 2.0 parts by mass to 15.0 parts by mass with respect to 100 parts by mass of the polyols. If this content is 2.0 parts by mass or more, strength such as tensile strength can be ensured. Also, if the above content is 15.0 parts by mass or less, appropriate hardness can be obtained and high resilience can be imparted.

[0043] The mixed raw material may contain other components other than the above as required. Examples of other components include antioxidants, ultraviolet absorbers, thickeners, plasticizers, antibacterial agents, and colorants. As the antioxidant, for example, dibutylhydroxytoluene and hindered phenol-based antioxidants can be mentioned, but from the viewpoint of reducing the content of volatile organic compounds, it is particularly preferable to use a hindered phenol-based antioxidant having a molecular weight of 300 or more. Examples of the thickener include calcium carbonate, aluminum hydroxide, and magnesium hydroxide. It is also known that these thickeners impart flame retardancy to polyurethane foams, and they are also preferable from the viewpoint of improving the flame retardancy of the sheet 10.

[0044] From the perspective of shock absorption, the polyurethane foam preferably has either an open-cell structure or a semi-open-cell structure, more preferably an open-cell structure. The open-cell structure and the semi-open-cell structure are different from the closed-cell structure and are structures in which the cells have pores. 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 method) defined in JIS L1096:2010. The Gurley air permeability of the polyurethane foam is, for example, 0.5 seconds / 100 mL or more and 50 seconds / 100 mL or less.

[0045] From the perspective of maintaining the 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 perspectives, 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 the polyurethane foam can be calculated by dividing the cumulative cell diameter by the number of cells for the cells in contact with a 25 mm straight line when the cross-section of the polyurethane foam is observed at a magnification of 200 times with a scanning electron microscope. Also, from the perspective of maintaining the elasticity of the polyurethane foam, the thickness of the cell membrane constituting the cells is preferably 10 μm or less, more preferably 5 μm or less.

[0046] From the perspective of maintaining the uniformity of the product, it is preferable that 70% or more of the cells are within ±50 μm of the average cell diameter, more preferably within ±30 μm, and particularly preferably within ±20 μm. The cell diameter distribution can be calculated based on the cell diameters when the average cell diameter described above is measured.

[0047] From the perspective of shock absorption, the shape of the cell is preferably substantially spherical. The shape of the cell can be confirmed by observing the cross-section of the polyurethane foam under a microscope. For example, it is preferable that the average value of the circularity (hereinafter also referred to as the average circularity) calculated by the following formula (1) of the cell is 0.6 or more. Circularity = 4π (cross-sectional area of the cell (mm 2 )) / (perimeter length of the cell cross-section (mm)) 2 (1) The above circularity represents how close the cell cross-section is to a perfect circle, and the closer the circularity is to 1, the closer it is to a perfect circle. The measurement of the average circularity can be calculated, for example, by using image analysis software to measure the bubble perimeter and bubble area for all bubbles within a range of 1 mm × 1 mm, calculating the circularity rate for each, and averaging them.

[0048] Note that the bubble structure, average cell diameter, cell diameter distribution, and cell shape of the polyurethane foam can be controlled by adjusting the manufacturing conditions in the mechanical froth method, the blending composition of the mixed raw materials, and the viscosity of the mixed raw materials.

[0049] The thickness of the polyurethane foam is not particularly limited. From the perspective of shock absorption, the thickness of the polyurethane foam is preferably 0.5 mm or more, more preferably 1.0 mm or more, and still more preferably 2.0 mm or more. From the perspective 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 still more preferably 5.0 mm or less. From these perspectives, 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 still more preferably 2.0 mm or more and 5.0 mm or less.

[0050] The specific gravity of the polyurethane foam is not particularly limited. From the perspective of hardness, the specific gravity of the polyurethane foam is preferably 0.05 g / cm 3 or more, more preferably 0.08 g / cm 3 or more, and still more preferably 0.15 g / cm 3The above is more preferable. From the viewpoint of impact absorbency, the specific gravity of the polyurethane foam is preferably 0.70 g / cm 3 or less, more preferably 0.60 g / cm 3 or less, and still more preferably 0.50 g / cm 3 or less. From these viewpoints, the specific gravity of the polyurethane foam is preferably 0.05 g / cm 3 or more and 0.70 g / cm 3 or less, more preferably 0.08 g / cm 3 or more and 0.60 g / cm 3 or less, and still more preferably 0.15 g / cm 3 or more and 0.50 g / cm 3 or less.

[0051] 2. First Film Layer 11 The first film layer 11 is composed of a first polyurethane film. In this embodiment, an example is given in which the first film layer 11 is a surface layer appearing on the surface 10A of the sheet 10. The first polyurethane film can be obtained by reacting a mixed raw material containing polyols and polyisocyanates.

[0052] As the polyols, polyester polyols, polyether polyols, polycarbonate polyols, polymer polyols, and mixtures thereof can be used. Among these, from the viewpoint of abrasion resistance, it is preferable to contain polyester polyols.

[0053] The above polyester polyol can be obtained, for example, by reacting a dicarboxylic acid and a glycol according to a conventional method. Examples of the above 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 above 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. The polyester polyols obtained therefrom have a linear structure, but branched polyesters can also be obtained by using a trivalent or higher ester-forming component.

[0054] When the total amount of polyols is 100 parts by mass, the content of the polyester polyol in the mixed raw materials is preferably 50 to 100 parts by mass, more preferably 70 to 98 parts by mass, and still more preferably 85 to 95 parts by mass. If the content of the polyester polyol is at least the above lower limit value, the abrasion resistance will be good. If the content of the polyester polyol is at most the above upper limit value, it is preferable from the viewpoint of physical strength.

[0055] 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.

[0056] The first polyurethane film can further contain additives such as a flame retardant, an adhesion promoter, a colorant, a plasticizer, and combinations thereof. The additives are selected so as not to have a significant adverse effect on the desired properties of the first polyurethane film. In a configuration where the polyurethane foam contains expanded graphite as a flame retardant, it is preferable to use the first polyurethane film containing a colorant. If the first polyurethane film is colorless and transparent, the expanded graphite in the polyurethane foam is visible through the first film layer, and the color of the sheet 10 is restricted. By using the first polyurethane film containing a colorant, the degree of freedom of the color of the sheet 10 can be increased.

[0057] The thickness of the first polyurethane film is not particularly limited. From the viewpoints of abrasion resistance and moldability, the thickness of the first polyurethane film is preferably 0.001 mm or more, more preferably 0.005 mm or more, and still more preferably 0.010 mm or more. From the viewpoints of stretchability and cost, the thickness of the first polyurethane film is preferably 0.200 mm or less, more preferably 0.100 mm or less, and still more preferably 0.050 mm or less. From these viewpoints, the thickness of the first polyurethane film is preferably 0.001 mm or more and 0.200 mm or less, more preferably 0.005 mm or more and 0.100 mm or less, and still more preferably 0.010 mm or more and 0.050 mm or less.

[0058] The specific gravity of the first polyurethane film is not particularly limited. From the viewpoint of air permeability, the specific gravity of the first polyurethane film is preferably 0.8 g / cm 3 or more, more preferably 0.9 g / cm 3 or more, and still more preferably 0.95 g / cm 3 or more. From the viewpoint of flexibility, the specific gravity of the first polyurethane film is preferably 2.0 g / cm 3 or less, more preferably 1.5 g / cm 3 or less, and still more preferably 1.2 g / cm 3 or less. From these viewpoints, the specific gravity of the first polyurethane film is 0.8 g / cm 3 or more and 2.0 g / cm3 The following is preferable, 0.9 g / cm 3 or more and 1.5 g / cm 3 or less is more preferable, 0.95 g / cm 3 or more and 1.2 g / cm 3 is even more preferable.

[0059] The elongation of the first polyurethane film is not particularly limited. The elongation of the first polyurethane film is preferably 150% or more, more preferably 150% to 500%, and even more preferably 200% to 500%. When this elongation is at or above the lower limit value, the followability is excellent as compared with the case of using a general PET film or the like. Note that this elongation is a value measured in accordance with JIS K 6251.

[0060] The first polyurethane film is preferably a non-foamed polyurethane film. It is more preferable to use a film that is substantially pore-free. Examples of the film-forming method of the first polyurethane film include a wet method and a dry method. However, in order to obtain a substantially pore-free first polyurethane film, it is preferable to use the dry method. Specifically, it is coated on a first base material 21 with releasability such as a release paper or a release film using a normal coating method, for example, a knife coater, a comma coater, a reverse coater, etc., and formed into a film. The fact that the first polyurethane film is substantially pore-free can be evaluated by measuring the air permeability of the first polyurethane film. For example, the first polyurethane film may be a film having an Gurley air permeability exceeding 10,000 seconds / 100 mL.

[0061] As shown in FIG. 2, the first film layer 11 preferably has an uneven shape 11A on the surface 10A. The uneven shape 11A constitutes, for example, a matte pattern or a geometric pattern. The uneven shape 11A can be integrally formed on the first polyurethane film. For example, the uneven shape 11A can be formed by transferring the shape imparted to the first base material 21 described in the manufacturing method of the sheet 10 described later.

[0062] 3. Second Film Layer 13 The second film layer 13 is composed of a second polyurethane film. In this embodiment, an example is given where the second film layer 13 is the back surface layer that appears on the back surface 10B of the sheet 10. That is, in the second film layer 13 of this embodiment, the surface on the side opposite to the foaming layer 12 side is the installation surface that contacts the object to be installed. The second polyurethane film can be obtained by reacting a mixed raw material containing polyols and polyisocyanates.

[0063] As the polyols, polyester polyol, polyether polyol, polycarbonate polyol, polymer polyol, and mixtures thereof can be used. Among these, from the viewpoint of improving the strength while ensuring flexibility in order to increase the friction coefficient, it is preferable to use a combination of polyether polyol and polyester polyol.

[0064] As the polyether polyol, for example, a polyether polyol composed of a polymer obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to a polyhydric alcohol such as glycerin or glycol can be preferably used. As the polyether polyol, only one kind of polyether polyol may be contained, or two or more kinds of polyether polyols having different number average molecular weights, functional groups, etc. may be combined and contained.

[0065] The polyester polyol can be obtained, for example, by reacting a dicarboxylic acid and 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. The polyester polyols obtained from these are linear in structure, but branched polyesters can also be obtained by using a trivalent or higher ester-forming component.

[0066] The contents of the polyether polyol and the polyester polyol in the mixed raw materials are appropriately adjusted according to the physical properties required for the second film layer 13. The mass ratio of the polyether polyol to the polyester polyol (polyether polyol: polyester polyol) is preferably 5:95 to 50:50, more preferably 8:92 to 40:60, and even more preferably 10:90 to 30:70. When the total amount of the polyol components is 100 parts by mass, the total content of the polyether polyol and the polyester polyol is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 70 parts by mass or more.

[0067] 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, xylylene diisocyanate, and aliphatic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and the like.

[0068] The second polyurethane film can further contain additives such as a flame retardant, an adhesion promoter, a colorant, a plasticizer, and combinations thereof. The additives are selected so as not to have a significant adverse effect on the desired properties of the second polyurethane film.

[0069] The thickness of the second polyurethane film is not particularly limited. From the viewpoints of durability and moldability, the thickness of the second polyurethane film is preferably 0.001 mm or more, more preferably 0.005 mm or more, and still more preferably 0.010 mm or more. From the viewpoints of stretchability and cost, the thickness of the second polyurethane film is preferably 0.200 mm or less, more preferably 0.100 mm or less, and still more preferably 0.050 mm or less. From these viewpoints, the thickness of the second polyurethane film is preferably 0.001 mm or more and 0.200 mm or less, more preferably 0.005 mm or more and 0.100 mm or less, and still more preferably 0.010 mm or more and 0.050 mm or less.

[0070] The specific gravity of the second polyurethane film is not particularly limited. From the viewpoint of enhancing durability, the specific gravity of the second polyurethane film is preferably 0.8 g / cm 3 or more, more preferably 0.9 g / cm 3 or more, and still more preferably 0.95 g / cm 3 or more. From the viewpoint of ease of handling of the product due to weight reduction, the specific gravity of the second polyurethane film is preferably 2.0 g / cm 3 or less, more preferably 1.5 g / cm 3The following is more preferable, 1.2 g / cm 3 The following is even more preferable. From these viewpoints, the specific gravity of the second polyurethane film is 0.8 g / cm 3 or more and 2.0 g / cm 3 or less is preferable, 0.9 g / cm 3 or more and 1.5 g / cm 3 or less is more preferable, 0.95 g / cm 3 or more and 1.2 g / cm 3 is even more preferable.

[0071] As shown in FIG. 2, the second film layer 13 preferably has an uneven shape 13A on the installation surface. The uneven shape 13A is configured to have a plurality of anti-slip protrusions such as columnar shapes and hemispherical (dome) shapes, for example. The uneven shape 13A can be integrally formed on the second polyurethane film by embossing. In a configuration having such an uneven shape 13A, it is preferable that the anti-slip property of the sheet 10 can be improved without performing separate anti-slip processing or the like after forming the sheet. For example, the uneven shape 13A can be formed by transferring the shape imparted to the second base material 23 described in the manufacturing method of the sheet 10 described later.

[0072] 4. Configuration of the sheet The sheet 10 is, for example, a laminate in which a first film layer 11 of ester-based polyurethane, a foamed layer 12 of ether-based polyurethane, and a second film layer 13 of ether / ester-based polyurethane are laminated in this order. It is preferable that the foamed layer 12 and the first film layer 11 are directly in contact and adhered. Also, it is preferable that the foamed layer 12 and the second film layer 13 are directly in contact and adhered.

[0073] The sheet 10 is suitable as a floor covering (carpet, flooring material). When used as a floor covering, the sheet 10 is installed on a laying surface such as indoors, a passage, and the floor of a vehicle with the surface 10A facing up. The first film layer 11 is exposed on the side opposite to the foamed layer 12 and comes into contact with people walking on the surface 10A side or objects placed on the surface 10A side. That is, the first film layer 11 is interposed between the foamed layer 12 and people walking on the surface 10A side or objects placed on the surface 10A side. Therefore, even if an additive such as expanded graphite that may fall off or transfer color is added to the foamed layer 12, the additive can be prevented from coming into contact with people or objects. The second film layer 13 is exposed on the side opposite to the foam layer 12 and contacts the object to be installed, such as a floor. That is, the second film layer 13 is interposed between the object to be installed, such as a floor material, and the foam layer 12. Therefore, even if an additive such as expanded graphite that may fall off or transfer color is added to the foam layer 12, the additive can be prevented from adhering to the object to be installed. The configuration of the sheet is not limited to this. For example, unlike the present embodiment, the sheet may further include an optional layer on the upper side of the first film layer or between the first film layer and the foam layer. The sheet may further include an optional layer on the lower side of the second film layer or between the foam layer and the second film layer.

[0074] The Taber abrasion of the surface 10A of the sheet 10 facing the first film 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 foam layer 12 alone is greater than the Taber abrasion of the surface facing the first film 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.

[0075] The static friction coefficient of the surface 10B of the sheet 10 facing the second film layer 13 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. This coefficient of static friction is measured in accordance with JIS K7125 under an atmosphere of 23°C and 50% relative humidity.

[0076] When the surface on the side opposite to the foamed layer 12 of the second film layer 13 is the installation surface that contacts the object to be installed, the second film layer 13 functions as an anti-slip layer with respect to the laying surface. Therefore, even if a configuration such as an adhesive layer is not provided between the second film layer 13 and the laying surface, the grip of the sheet 10 with respect to the laying surface can be ensured.

[0077] The 25% compression load of the sheet 10 is not particularly limited. The 25% compression load (25% CLD, JIS K 6254:2010) of the sheet 10 is preferably 0.01 to 0.5 MPa.

[0078] The shock absorbency of the sheet 10 is not particularly limited. The shock load of the sheet 10 measured by the measurement method described later is preferably 0.35 kN or less.

[0079] 5. Manufacturing method of the sheet 10 The manufacturing method of the sheet 10 is, for example, supplying a polyurethane foam raw material between a first polyurethane film and a second polyurethane film that travel in one direction, and reacting and curing the polyurethane foam raw material to form a polyurethane foam. From the viewpoint of suppressing the gas floating of the first polyurethane film that appears on the surface 10A, it is preferable to heat the supplied polyurethane foam raw material with the second polyurethane film positioned above the polyurethane foam raw material in a posture, and react and cure it to form a polyurethane foam. The manufacturing method of the sheet 10 of the present embodiment manufactures a polyurethane foam by the mechanical froth method. The sheet 10 can be manufactured, for example, using the manufacturing apparatus 30 shown in FIG. 3.

[0080] The manufacturing apparatus 30 includes a mixing section (not shown), a roll mechanism 32 including supply rolls 33, 34 and a product recovery roll 35, a discharge nozzle 36, and a heating section 37. The mixing section is a part that mixes raw materials to obtain the polyurethane foam raw material M. The first supply roll 33 is a part around which the first polyurethane film with the first base material 21 is wound and supplies the first polyurethane film by a drive source (not shown). The second supply roll 34 is a part around which the second polyurethane film with the second base material 23 is wound and supplies the second polyurethane film by a drive source (not shown). The product recovery roll 35 is a part that winds the sheet 10 in a roll shape and recovers it. The discharge nozzle 36 is a part that supplies the polyurethane foam raw material M between the first polyurethane film and the second polyurethane film. The heating section 37 is composed of a heater or the like that heats the supplied polyurethane foam raw material M. Further, the manufacturing apparatus 30 includes a first base material recovery roll 38 that peels and recovers the first base material 21 from the first polyurethane film, and a second base material recovery roll 39 that peels and recovers the second base material 23 from the second polyurethane film.

[0081] The sheet 10 can be manufactured as follows. First, the first polyurethane film with the first base material 21 is continuously supplied from the first supply roll 33, and the second polyurethane film with the second base material 23 is continuously supplied from the second supply roll 34. In the process where the first polyurethane film and the second polyurethane film are continuously supplied, the polyurethane foam raw material M is supplied between the first polyurethane film and the second polyurethane film from the discharge nozzle 36. At this time, the thickness of the sheet 10 can be set according to the distance between the first polyurethane film and the second polyurethane film.

[0082] Subsequently, the polyurethane foam raw material M is heated in the heating unit 37 to cause reaction and curing. At this time, the polyurethane foam raw material M is heated under the condition that the product temperature becomes the expansion start temperature of the expanded graphite (for example, 170°C or lower). The heating by the heating unit 37 is performed with the second polyurethane film positioned on the upper side. In this way, even if the expanded graphite added to the polyurethane foam raw material partially expands and gas is generated, it is difficult for the gas to move to the first polyurethane film side, and it is possible to suppress the occurrence of gas floating on the surface 10A side of the sheet 10. After that, after the first polyurethane film, the polyurethane foam, and the second polyurethane film in the laminated state are fixed, the first base material 21 and the second base material 23 are peeled off, and the sheet 10 is wound around the product recovery roll 35.

[0083] The sheet 10 obtained in this way can be cut into a predetermined shape and used as a floor covering (carpet, flooring material). In addition to floor coverings, the sheet 10 can be applied to coasters, pot mats, shoe insoles, vehicle seats, and the like.

[0084] 6. Effects of this Embodiment Conventionally, in removable floor coverings (carpet materials, flooring materials) for personal use and in the home, fiber materials and resin foams such as polyethylene foam and EVA have been used. Basic functions such as cleanability, ease of installation, walkability, and durability are required for floor coverings. Furthermore, in recent years, especially in housing (facilities) corresponding to caregiving and child-rearing, due to the issues of barrier-free design and ensuring safety during falls, floor coverings with few steps (thin thickness) and excellent shock absorption performance have been demanded. Thus, the demand for sheets that have the basic functions of floor coverings and high shock absorption is increasing. Also, in facilities and buildings where a large number of unspecified people come and go, such as care facilities and accommodation facilities, performance that meets the flameproof performance standards defined by the Fire Prevention Law is required, but in reality, there is no floor covering that satisfies all of them.

[0085] The sheet 10 of this embodiment includes a first film layer 11, a foamed layer 12, and a second film layer 13 in this order, thereby ensuring basic performances such as impact absorbency and flame retardancy, and improving the abrasion resistance of the front surface 10A and the non-slip property of the back surface 10B. Since the sheet 10 has high impact absorbency, it is possible to reduce the thickness to cope with wheelchairs, walkers, etc. required by care recipients and infants and young children, and reduce the step difference. Further, at the time of a fall, the impact can be absorbed to ensure safety. When the foamed layer 12 has high resilience, the feet do not sink too much during walking, and the walkability is good. Similarly, when the foamed layer 12 has high resilience, the wheels of the wheelchair or walker do not sink too much during traveling, and it is easy to travel.

[0086] Since the sheet 10 has high abrasion resistance of the first film layer 11, durability can be ensured. For example, when used as a floor covering, abrasion due to rubbing associated with wheelchair use, walking, and cleaning can be suppressed, and damage to the sheet 10 can be suppressed. Therefore, the life of the sheet 10 can be extended. Further, in the sheet 10, solvents and dirt hardly penetrate into the first film layer 11, and deposits attached to the first film layer 11 can be easily wiped off. Therefore, the sheet 10 has good cleanability. Further, the first film layer 11 has high chemical resistance and can contribute to improving the durability of the sheet 10.

[0087] Since the sheet 10 has high grip performance of the second film layer 13, it is excellent in easy installation. Specifically, the sheet 10 is hardly slippery with respect to the laying surface even when the second film layer 13 is simply placed in contact with the laying surface. Therefore, when installing the sheet 10, it can be directly installed on the laying surface without using an adhesive or an adhesive as in the prior art. Further, when an adhesive or an adhesive is not used, there is no need to spend time peeling off the adhesive or the adhesive remaining on the laying surface when the floor covering is removed using a solvent. When the polyurethane foam contains a flame retardant, there is a concern that the static friction coefficient of the foamed layer 12 alone may decrease. In this embodiment, since the second film layer 13 is provided together with the foamed layer 12, while ensuring functions such as impact absorbency and flame retardancy by the foamed layer 12, the grip force can also be ensured by the second film layer 13.

[0088] When the polyurethane foam contains a flame retardant, the flame retardancy of the sheet 10 can be improved. Specifically, the sheet 10 can be imparted with flame-retardant performance applicable to the criteria of Article 4, Paragraph 3 of the Enforcement Regulations of the Fire Services Act. Further, when a halogen-derived material is not used for the flame retardant, it is also possible to make a formulation that is friendly to the environment. Furthermore, in the present embodiment, since the foam layer 12 is covered with the first film layer 11 and the second film layer 13, contact between the flame retardant and people and objects can be suppressed, and also, dropout of the flame retardant in the polyurethane foam can be suppressed.

[0089] In the manufacturing method of the sheet 10 of the present embodiment, since the first film layer 11, the foam layer 12, and the second film layer 13 are integrally formed, there is no need for the labor of bonding the first film layer 11, the foam layer 12, and the second film layer 13. Further, since the first film layer 11, the foam layer 12, and the second film layer 13 are all made of a polyurethane resin, bonding strength is ensured and peeling hardly occurs.

[0090] The manufacturing method of the sheet 10 of the present embodiment easily forms the sheet 10 in a long and narrow shape that is long in one direction. Such a sheet 10 can be installed on a large-area laying surface with a single sheet and is easy to use as a floor covering. Further, the sheet 10 can be easily cut to a predetermined size to adjust the size.

[0091] Furthermore, in the manufacturing method of the sheet 10 of the present embodiment, even when the sheet 10 is wound into a roll, the first film layer 11 and the second film layer 13 are interposed between the previously wound foam layer 12 and the subsequently wound foam layer 12. If the previously wound foam layer 12 and the subsequently wound foam layer 12 come into contact, measures are taken to prevent the foam layers 12 from blocking, for example, by laminating a release paper or the like on the foam layer 12 or applying a UV (ultraviolet) coat. Since the first film layer 11 and the second film layer 13 of the present embodiment are interposed between the previously wound foam layer 12 and the subsequently wound foam layer 12, blocking can be suppressed without laminating a release paper or the like or applying a UV coat to the foam layer 12. Thus, the first film layer 11 and the second film layer 13 of the present embodiment also function as layers for suppressing blocking. When the sheet 10 of the present embodiment is configured to be wound into a roll, the sheet 10 is easy to manufacture and easy to handle.

Example

[0092] Next, the above embodiment will be described more specifically with reference to examples and comparative examples. 1. Production of Sheet First, as the first polyurethane film for Examples and Comparative Example 2, a film of polyester-based polyurethane (manufactured by Seiko Chemical Co., Ltd., Luxskin U2245) was prepared. The thickness of the first polyurethane film was set to 0.04 mm. The specific gravity of the first polyurethane film was 1.1 g / cm 3 It was. Also, as the second polyurethane film for the examples, a film of polyether / ester-based polyurethane (manufactured by Seiko Chemical Co., Ltd., Luxskin U2462) was prepared. The thickness of the second polyurethane film was set to 0.02 mm. The specific gravity of the second polyurethane film was 1.1 g / cm 3 It was. Embossing was performed on the installation surface of the second polyurethane film to provide an uneven shape. The thickness of the film having the uneven shape was measured as the dimension from the back surface to the top surface of the convex portion of the uneven shape.

[0093] Next, the components of the mixed raw materials used in the polyurethane foams of the examples and Comparative Examples 1 and 2 are shown below. Polymer polyol 1: Polymer polyol with a number average molecular weight of 3,000, a functionality of 3, and a polymer content of 22% by mass (manufactured by Asahi Glass Co., Ltd., EXCENOL 914) Polymer polyol 2: Polymer polyol with a number average molecular weight of 3,000, a functionality of 2, and a polymer content of 20% by mass (manufactured by Asahi Glass Co., Ltd., EXCENOL 913) Polymer polyol 3: Polymer polyol with a number average molecular weight of 3,000, a functionality of 3, and a polymer content of 40% by mass (manufactured by Sanyo Chemical Industries, Ltd., Sharpflow FS-7301) Polyether polyol: Polyoxypropylene glyceryl ether with a number average molecular weight of 600 and a functionality of 3 (manufactured by Sanyo Chemical Industries, Ltd., Sunnex GP-600) Polyester polyol: Polycaprolactone triol with a molecular weight of 540 and a functionality of 3 (manufactured by Daicel Chemical Industries, Ltd., Placcel 305) Crosslinking agent 1: Dipropylene glycol (manufactured by Asahi Glass Co., Ltd.) Crosslinking agent 2: MPO (2-methyl-1,3-propanediol) (manufactured by Dalian Chemical Co., Ltd.) Thickening agent: Aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., C-31) Foam stabilizer: Block copolymer of dimethylpolysiloxane and polyether (manufactured by Toray Dow Corning Co., Ltd., SZ-1952 ADDITIVE) Catalyst 1: Iron catalyst (manufactured by Nippon Chemical Industry Co., Ltd., FIN-P1) Catalyst 2: Zinc amine catalyst (manufactured by KING INDUSTRIES, Inc., K-KAT XK-622) Flame retardant 1: Expanded graphite (manufactured by Shijiazhuang ADT Carbonic Material Factory, SYZR-802FP) Flame retardant 2: Ammonium polyphosphate (manufactured by CBC Co., Ltd., Terajou C-30) Polyisocyanate: Polymeric MDI (manufactured by BASF INOAC Polyurethane Co., Ltd., Formlite 500B)

[0094]

Table 1

[0095] The sheet of the example was produced as follows. First, the mixed raw materials were put into a mixing head and stirred and mixed to be homogeneous while mixing an inert gas (nitrogen) in the range of 10% to 90% by volume. Then, the mixed raw materials were supplied between the above-mentioned first polyurethane film and the second polyurethane film that were continuously supplied, and heat-cured at 120°C to 170°C. In this way, a sheet was obtained in which a first film layer composed of the first polyurethane film, a foamed layer composed of the polyurethane foam, and a second film layer composed of the second polyurethane film were laminated in this order.

[0096] The sheet of Comparative Example 1 was produced as follows. The foamed layer was obtained in the same manner as the foamed layer of the example, except that a mold-releasing base material was used instead of the polyurethane film. After removing the mold-releasing base material, a UV coat was applied to both surfaces of the obtained foamed layer. The UV coat was performed by applying an acrylic resin and irradiating with UV. In this way, a sheet having coating layers on both surfaces and composed of a foamed layer made of polyurethane foam was obtained.

[0097] In the sheet of Comparative Example 1 thus obtained, the coating layer is exposed on the back side. The sheet of Comparative Example 1 is mainly subjected to a UV coat for the purpose of suppressing blocking. In other words, in fact, the coating layer cannot be abolished for convenience of production and handling in the sheet of Comparative Example 1. On the other hand, the sheet of the example can suppress blocking by the first film layer and the second film layer and does not have a coating layer.

[0098] The sheet of Comparative Example 2 was produced as follows. The foam layer was obtained in the same manner as the foam layer of the Example, except that the mixed raw materials were supplied onto the above-described first polyurethane film to which the mixed raw materials were continuously supplied, and heat-cured at 120°C to 170°C. In this way, a sheet in which a first film layer made of a first polyurethane film and a foam layer made of a polyurethane foam were laminated in this order was obtained. That is, the sheet of Comparative Example 2 is different from the Example in that it does not have a second film layer and the foam layer is exposed on the back surface.

[0099] 2. Measurement of average cell diameter For the sheet of the Example, the average cell diameter was measured by the method described in the embodiment. The average cell diameter of the polyurethane foam of the Example was 50 μm or more and 300 μm or less. A polyurethane foam having such cells is excellent in shock absorbency.

[0100] 3. Observation of the sheet The cross-section of the sheet of the Example was observed using a microscope. When the cross-section of the first polyurethane film was observed over 1200 μm, no pores were observed. Such a first polyurethane film is excellent in cleaning property. In addition, when the cross-section of the polyurethane foam was observed, substantially spherical cells were observed. The size of the cells was highly uniform. A polyurethane foam having such cells is excellent in shock absorbency.

[0101] 4. Evaluation Next, for the obtained sheets of the Example and Comparative Examples 1 and 2, the 25% compression load, anti-inflammatory property, Taber abrasion amount (mg) of the surface, coefficient of static friction of the back surface, Gurley air permeability (seconds / 100 mL), and shock absorbency were evaluated under the following conditions. In the Example, the surface is the surface on the side of the first polyurethane film (first film layer), and the back surface is the surface on the side of the second polyurethane film (first film layer). In Comparative Example 1, both sides of the polyurethane foam are the surface and the back surface. In Comparative Example 2, the surface is the surface on the side of the first polyurethane film, and the back surface is the surface on the side of the polyurethane foam (foam layer). The results are shown in Table 2.

[0102] [25% Compressive Load] The 25% compressive load (MPa) (25% CLD, JIS K 6254:2010) was measured as the compressive stress when a φ50 mm sample was compressed by 25% at a speed of 1 mm / min. The 25% compressive load of a commercially available pile carpet (thickness 8.0 mm) was 0.09 MPa. [Anti-inflammatory property] In accordance with Article 4-3 of the Enforcement Regulations of the Fire Service Act, the test was conducted by the 45° air mix burner method. When it met the judgment criteria, it was marked as "Conforms" in Table 2. Note that Comparative Example 1 did not conduct the test regarding the anti-inflammatory property. [Wear amount of the surface] It was measured according to JIS K7204 under the conditions of a wear wheel H-22, a rotational speed of 60 rpm, a load of 250 g, and a number of rotations of 1000. Each condition was appropriately specified according to the material of the sheet. [Coefficient of static friction of the back surface] It was measured in accordance with JIS K7125 under an atmosphere of a temperature of 23°C and a relative humidity of 50%. [ Gurley air permeability] It was determined according to the air permeability measurement Method B (Gurley method) specified in JIS L1096:2010 8.26.2. The compression amount was 50% and the range was 100 mL. Since Examples and Comparative Example 2 exceeded 300 seconds / 100 mL, the measurement was interrupted and marked as "No ventilation" in Table 2. [Impact absorbency] The sample was placed on a plastic tile (P tile), and a 112 g steel ball was freely dropped from a falling height of 200 mm, and the impact load (kN) was measured. The impact load measured without placing the sample was 0.97 kN. The impact load of a commercially available pile carpet (thickness 8.0 mm) was 0.36 kN.

[0103]

Table 2

[0104] As shown in Table 2, it was found that the wear amount on the surface of the example was smaller than that of Comparative Example 1, and the wear resistance was excellent. Also, it was found that the static friction coefficient on the back surface of the example was larger than that of Comparative Example 1 and Comparative Example 2, and the grip property was excellent. Furthermore, it was suggested that the example had almost no air permeability and excellent cleaning property. Additionally, it was confirmed that the example was excellent in basic performances such as 25% compression load, anti-inflammability, and shock absorbability.

[0105] 5. Effects of the Example According to the above examples, it is possible to provide a sheet excellent in basic performances with improved wear resistance on the surface and non-slip property on the back surface, and a method for manufacturing the sheet excellent in basic performances with improved wear resistance on the surface and non-slip property on the back surface.

[0106] The present disclosure is not limited to the embodiments detailed above, and various modifications or changes are possible within the scope shown in the claims of the present disclosure.

Explanation of Reference Numerals

[0107] 10 … Sheet 10A… Surface 10B… Back surface (surface on the side of the second film layer) 11 … First film layer 11A… Concavo-convex shape 12 … Foam layer 13 … Second film layer 13A… Concavo-convex shape 21 … First base material 23 … Second base material 30 … Manufacturing apparatus 32 … Roll mechanism 33 … First supply roll 34 … Second supply roll 35 … Product recovery roll 36 … Discharge nozzle 37 … Heating unit 38 … First base material recovery roll 39 … Second base material recovery roll

Claims

1. a first film layer composed of a first polyurethane film; A foam layer made of a polyurethane foam containing a flame retardant; a second film layer composed of a second polyurethane film, in this order; A sheet that satisfies the following (1). (1) The average cell diameter of the polyurethane foam is 50 μm or more and 300 μm or less, The sheet has a static friction coefficient of 0.3 to 10.0 on the surface of the second film layer side, measured in accordance with JIS K7125, in an atmosphere having a temperature of 23° C. and a relative humidity of 50%.

2. a first film layer composed of a first polyurethane film; A foam layer made of a polyurethane foam containing a flame retardant; a second film layer composed of a second polyurethane film, in this order; A sheet that satisfies the following (2). (2) The polyurethane foam is a polyurethane foam using a mixed raw material containing polyols and polyisocyanates, and the polyols include a polymer polyol. The content of the polymer polyol in the mixed raw material is 80 parts by mass or more when the total amount of the polyols is 100 parts by mass.

3. a first film layer composed of a first polyurethane film; A foam layer made of a polyurethane foam containing a flame retardant; a second film layer composed of a second polyurethane film, in this order; A sheet that satisfies the following (3). (3) The polyurethane foam contains, as the flame retardant, one or more of expandable graphite, melamine resin, and halogen-based flame retardant.

4. a first film layer composed of a first polyurethane film; A foam layer made of polyurethane foam; a second film layer composed of a second polyurethane film, in this order; The polyurethane foam has an average cell diameter of 50 μm or more and 300 μm or less, A method for producing a sheet having a thickness of the polyurethane foam of 2 mm or more and 20 mm or less, comprising the steps of: A method for manufacturing a sheet, comprising: supplying a polyurethane foam raw material between the first polyurethane film and the second polyurethane film traveling in one direction; and reacting and curing the polyurethane foam raw material to form the polyurethane foam.

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