Sheet

Abstract

To provide a sheet high in wear resistance and shock absorption, and a method for manufacturing the same.SOLUTION: A sheet 10 includes a skin layer 11 formed of a polyurethane film and a foam layer 12 formed of a polyurethane foam having an average cell diameter of 50 μm or more and 300 μm or less, or a sheet includes a skin layer formed of a polyurethane film and an installation layer formed of a polyurethane foam. The amount of taber wear measured on the conditions of a wear wheel of H-22, a rotational speed of 60 rpm, a load of 250 g and a rotation frequency of 1000 times according to JIS K7204 in a surface on the skin layer side is 250 mg or less.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 urethane foam molded product that can be used as a floor mat or the like.

Prior Art Documents

Patent Documents

[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 abrasion resistance and shock absorption. An object of the present disclosure is to provide a sheet having high abrasion resistance and shock absorption, and a method for manufacturing the sheet having high abrasion resistance and shock absorption. The present disclosure can be realized in the following forms.

Means for Solving the Problems

[0005] An outer skin layer composed of a polyurethane film, A foam layer composed of a polyurethane foam, and comprising A sheet in which the average cell diameter of the polyurethane foam is 50 μm or more and 300 μm or less.

[0006] An outer skin layer composed of a polyurethane film, An installation layer composed of a polyurethane foam, and a sheet provided with

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

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a sheet having high abrasion resistance and impact absorbency, and a method for manufacturing a sheet having high abrasion resistance and impact absorbency.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Here, desirable examples of the present disclosure are shown.

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

[0012] The above sheet preferably has a static friction coefficient on the surface of the foam layer or the installation layer side, measured according to JIS K7125, of 0.3 or more and 10.0 or less in an atmosphere of 23°C and 50% relative humidity.

[0013] Hereinafter, the present disclosure will be described in detail. In this specification, for a 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 "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".

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

[0015] 1. Foamed layer 12 The foamed layer 12 is made 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.

[0016] As the polyols, it is preferable to use in combination at least three types of polyols: (A) a first polyol composed of polymer polyol, (B) a second polyol composed of polyether polyol, and (C) a third polyol composed of polyester polyol. By using polyols in combination in this way, the low compression residual strain property and shock absorption property of the sheet 10 can be improved. Also, in the configuration where the foamed layer 12 is the installation layer, the grip property of the sheet 10 can be improved.

[0017] The first polyol is, for example, a polymeric polyol having a number average molecular weight of 1500 to 4500 (preferably 2000 to 4000) and a functionality of 3. The first polyol, when used in combination with the second polyol and the third polyol, imparts strength such as tensile strength, hardness according to the application, and flexibility to the polyurethane foam. As the first polyol, for example, a polymeric 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. Note that the number average molecular weight of the first polyol means the number average molecular weight of the base polyol.

[0018] Also, the polymer content of the first polyol (mass ratio of the portion other than the base polyol to the whole polymeric 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 decrease. Note that the first polyol may contain only one kind of polymeric polyol, or two or more kinds of polymeric polyols having different number average molecular weights, polymer contents, etc. may be combined and contained.

[0019] When the total amount of polyols is 100 parts by mass, the content of the first polyol in the mixed raw materials is preferably 50 parts by mass to 80 parts by mass, more preferably 55 parts by mass to 78 parts by mass, and still more preferably 58 parts by mass to 70 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 terms of tensile strength, tear strength, etc. 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 residual distortion to the polyurethane foam, and further improves the strength such as tensile strength and low compression residual distortion of the polyurethane foam when used in combination with the third polyol.

[0021] 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.

[0022] When the total amount of polyols is 100 parts by mass, the content of the second polyol in the mixed raw materials is preferably 5 to 16 parts by mass. If this content is 5 parts by mass or more, sufficient low compression residual distortion can be obtained. Also, if the above content exceeds 16 parts by mass, low resilience is exhibited. From the viewpoint of obtaining a high resilience polyurethane foam, it is preferable to make the above content 16 parts by mass or less. Further, when the above content of the second polyol is 7 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 of hydrolyzability and hardness. The content of the second polyol is not particularly limited, but may be more than the content of the third polyol.

[0023] The third polyol is, for example, a polyester polyol having 2 or 3 functional groups. 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 property of the polyurethane foam. Further, the third polyol also has an 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. Examples of the polycaprolactone-based polyester polyol include polyester polyols obtained by ring-opening addition polymerization of lactones such as ε-caprolactone. Examples of the adipate-based polyester polyol include polyester polyols obtained by polycondensation of a polyfunctional carboxylic acid and a polyfunctional hydroxy compound. Among these polyester polyols, it is preferable to use a polycaprolactone-based polyester polyol having 3 functional groups from the viewpoints of making hydrolysis less likely to occur and reducing the volatile organic compound content.

[0025] 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 highly resilient polyurethane foam, it is preferable to set the above content to be not less than the lower limit value. Also, if the above content is 6 parts by mass or less, an increase in compression set can be suppressed and low compression set property can be ensured.

[0026] In addition, as the polyols, other polyols other than the above-mentioned first to third polyols may be contained. As the other polyols, any polyols generally used in polyurethane foams can be used without particular limitation. In addition, antioxidants may be blended in the above-mentioned polyols to suppress oxidation of the components. However, 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 using hindered phenol antioxidants having 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; aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI); or modified polyisocyanates such as free isocyanate prepolymers obtained by reacting these with polyols and carbodiimide-modified polyisocyanates. These polyisocyanates may be contained alone or in combination of two or more.

[0028] 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 using them as starting materials for the polyisocyanates. Also, the functional group number of the polyisocyanates is preferably in the range of 2.0 to 2.2.

[0029] Incidentally, 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 and high resilience.

[0030] 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, for example, a silicone-based foam stabilizer can be used. 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. As the above 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 the low-viscosity polyol 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 materials is preferably 3 to 6 parts by mass with respect to 100 parts by mass of the polyols. If this content is 3 parts by mass or more, the foaming power becomes sufficient, and a uniform cell structure can be formed and the density can be reduced. Also, even if it is contained in excess of 6 parts by mass, no further dramatic improvement in foaming 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 used to promote the urethanization reaction between polyols and polyisocyanates, and the mixed raw material preferably contains a catalyst. As the catalyst, known catalysts commonly used in polyurethane foams can be used, for example, organometallic compounds such as ferric acetylacetonate, stannous octoate, tin octoate (stannous 2-ethylhexanoate), tertiary amines such as triethylenediamine, dimethylethanolamine, N,N´,N´-trimethylaminoethylpiperazine, acetates, and alkali metal alcoholates.

[0033] The content of the catalyst in the mixed raw material is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of polyols. If this content is 0.1 part by mass or more, the urethanization reaction can be sufficiently promoted. If the above content is 5.0 parts by mass or less, excessive promotion of the urethanization reaction can be suppressed, and the formation of the cell structure can be made uniform.

[0034] 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 can be used, 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, amines such as ethylenediamine, diethylenetriamine, hexamethylenediamine, hydrazine, diethyltoluenediamine, diethylenetriamine, aminoalcohols such as diethanolamine, 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 to 10.0 parts by mass with respect to 100 parts by mass of the polyols. If this content is 2.0 parts by mass or more, the strength such as tensile strength can be ensured. Further, if the above content is 10.0 parts by mass or less, an appropriate hardness can be obtained and high resilience can be imparted.

[0036] The mixed raw material may contain other components other than the 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. 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. Examples of the flame retardant include expanded graphite, phosphate esters, melamine resins, and halogen-based flame retardants.

[0037] From the viewpoint of impact absorption resistance, the polyurethane foam preferably has either a closed-cell structure or a semi-closed-cell structure, and more preferably has a closed-cell structure. The closed-cell structure and the semi-closed-cell structure are different from the open-cell structure and are structures in which pores are present in the cells. 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 B method ( Gurley 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 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 observing a cross-section of the polyurethane foam with a scanning electron microscope at a magnification of 200 times. 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, and more preferably 5 μm or less.

[0039] 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 measuring the average cell diameter described above.

[0040] From the perspective of shock absorption, the shape of the cells is preferably substantially spherical. The shape of the cells can be confirmed by observing the cross-section of the polyurethane foam with 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 cells is 0.6 or more. Circularity = 4π((Cross-sectional area of the cell (mm 2 )) / (Perimeter 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 average circularity can be measured, 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.

[0041] Note that the bubble structure, average cell diameter, cell diameter distribution, and cell shape of the polyurethane foam can be controlled by adjusting manufacturing conditions in the mechanical froth method, the composition of the mixed raw materials, and the viscosity of the mixed raw materials, etc.

[0042] 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.

[0043] 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 3 or more. From the perspective of shock absorption, 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 perspectives, 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 / cm3 Above 0.50 g / cm 3 The following is more preferable.

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

[0045] As the polyols, polyester polyol, polyether polyol, polycarbonate polyol, polymer polyol, and mixtures thereof can be used. Among these, from the viewpoint of wear resistance, it is preferable to contain polyester polyol.

[0046] 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-xylene diol, 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.

[0047] When the content of the polyester polyol in the mixed raw materials is based on 100 parts by mass of the total polyols, it 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.

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

[0049] The polyurethane film can further contain additives such as flame retardants, adhesion promoters, colorants, plasticizers, and combinations thereof. The additives are selected so as not to have a significant adverse effect on the desired properties of the polyurethane film.

[0050] The thickness of the polyurethane film is not particularly limited. From the viewpoints 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 still more preferably 0.003 mm or more. From the viewpoints 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 still 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 still 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 perspective of air permeability, the specific gravity of the polyurethane film is preferably 0.8 g / cm 3 or more, more preferably 0.9 g / cm 3 or more, and still more preferably 1.0 g / cm 3 or more. From the perspective of flexibility, the specific gravity of the polyurethane film is preferably 1.5 g / cm 3 or less, more preferably 1.3 g / cm 3 or less, and still more preferably 1.2 g / cm 3 or less. From these perspectives, the specific gravity of the polyurethane film is preferably 0.8 g / cm 3 or more and 1.5 g / cm 3 or less, more preferably 0.9 g / cm 3 or more and 1.3 g / cm 3 or less, and still more preferably 1.0 g / cm 3 or more and 1.2 g / cm 3 is even more preferable.

[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 still more preferably 200% to 500%. When this elongation is at or above the lower limit value, the followability is excellent compared to 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.

[0053] The polyurethane film is preferably a non-foamed polyurethane film. It is more preferable to use a substantially pore-free film. Examples of the film-forming method of the polyurethane film include a wet method and a dry method. However, to obtain a substantially pore-free polyurethane film, it is preferable to use the dry method. Specifically, it is coated on a mold-releasing substrate 13 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 polyurethane film is substantially pore-free can be evaluated by measuring the air permeability of the polyurethane film. For example, the polyurethane film may be a film having an Gurley air permeability exceeding 10,000 seconds / 100 mL.

[0054] FIG. 4 illustrates 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 constitutes, for example, a embossed pattern or a geometric pattern. When such a film 11P is used, since the uneven shape 11A appears on the surface 10A of the sheet 10 shown in FIG. 1, the appearance and touch feeling of the sheet 10 can be improved. The uneven shape 11A can be formed, for example, by transferring the shape imparted to the base material 13.

[0055] 3. Configuration of the Sheet The sheet 10 is, for example, a laminate in which an epidermal layer 11 of ester-based polyurethane and a foamed layer 12 of ether-based polyurethane are laminated. It is preferable that the foamed layer 12 and the epidermal layer 11 are in direct contact and adhered. The epidermal layer 11 is exposed on the side opposite to the foamed layer 12 and constitutes the surface 10A of the sheet 10. In the present embodiment, the foamed layer 12 is exposed on the side opposite to the epidermal layer 11 and constitutes the back surface 10B of the sheet 10. In the present disclosure, when the foamed layer 12 is exposed on the side opposite to the epidermal layer 11, the foamed layer 12 is also referred to as an installation layer.

[0056] The sheet 10 is suitable as a floor covering (carpet, floor material). When used as a floor covering, the sheet 10 is installed on a laying surface such as an indoor, passage, and floor of a vehicle with the surface 10A facing up. Note that the configuration of the sheet is not limited to this. For example, unlike the present embodiment, the sheet may further include an arbitrary layer such as an anti-slip layer on the side opposite to the epidermal layer with respect to the foamed layer.

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

[0058] The sheet 10 preferably has a coefficient of static friction of 0.3 or more and 10.0 or less, more preferably 0.5 or more and 7.0 or less, and even more preferably 1.0 or more and 4.0 or less on the surface 10B on the side of the foam layer 12. A high coefficient of static friction is one indicator of high grip. This coefficient of static friction is measured in an atmosphere of a temperature of 23°C and a relative humidity of 50% in accordance with JIS K7125.

[0059] When the foam layer 12 is the installation layer, the foam layer 12 comes into contact with the laying surface. The foam layer 12 has a high coefficient of static friction and functions as an anti-slip layer with respect to the laying surface. Therefore, even in a configuration where an adhesive layer or the like is not provided between the foam layer 12 and the laying surface, the grip of the sheet 10 with respect to the laying surface can be ensured.

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

[0061] The manufacturing apparatus 30 includes a mixing unit 31, a roll mechanism 32 including a supply roll 33 and a product recovery roll 34, a discharge nozzle 35, a thickness regulating unit 36, and a heating unit 38. The mixing unit 31 is a part that mixes raw materials to obtain the polyurethane foam raw material M. The supply roll 33 is a part where the polyurethane film with the base material 13 wound thereon is supplied with the polyurethane film by a drive source (not shown). The product recovery roll 34 is a part that winds and recovers the sheet 10 in a roll shape. The discharge nozzle 35 is a part that supplies the polyurethane foam raw material M onto the polyurethane film. The thickness regulating unit 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 unit 38 is composed of a heater or the like that heats the polyurethane foam raw material M on the polyurethane film. Further, the manufacturing apparatus 30 includes a base material recovery roll 39 that peels off and recovers the base material 13 from the polyurethane film.

[0062] The sheet 10 can be manufactured as follows. First, the polyurethane film with the base material 13 is continuously supplied from the supply roll 33. In the process of continuously supplying the polyurethane film, the polyurethane foam raw material M is supplied from the discharge nozzle 35 to the polyurethane film. The thickness of the supplied polyurethane foam raw material M is made a predetermined thickness by the thickness regulating unit 36. Subsequently, the polyurethane foam raw material M is heated in the heating unit 38 to react and cure. After the polyurethane foam and the polyurethane film in the laminated state are fixed, the base material 13 is peeled off, and the sheet 10 is wound around the product recovery roll 34.

[0063] 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 pads, shoe insoles, and vehicle seats.

[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 foot does not sink too much during walking, and the walking performance is good. Similarly, when the foam layer 12 has high resilience, the wheels of the wheelchair or walker do not sink too much during running, and it is easy to run.

[0069] In the manufacturing method of the seat 10 of the present embodiment, since the skin layer 11 and the foam layer 12 are integrally formed, there is no need to spend time bonding the skin layer 11 and the foam layer 12. Further, since both the skin layer 11 and the foam layer 12 are made of polyurethane resin, the adhesive strength is ensured and peeling is unlikely to occur.

[0070] The manufacturing method of the seat 10 of the present embodiment is easy to form the seat 10 in a long and narrow shape in one direction. Such a seat 10 can be installed on a large laying surface with a single sheet and is easy to use as a floor covering. Further, the seat 10 can be easily cut to a predetermined size to adjust the size.

[0071] Furthermore, in the manufacturing method of the seat 10 of the present embodiment, even when the seat 10 is wound in a roll shape, the skin layer 11 is 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 such as laminating a release paper or the like on the foam layer 12 or applying a UV (ultraviolet) coat are taken so that the foam layers 12 do not block each other. Since the skin layer 11 is interposed between the previously wound foam layer 12 and the subsequently wound foam layer 12 in the seat 10 of the present embodiment, blocking can be suppressed without laminating a release paper or the like or applying a UV coat to the foam layer 12. Thus, the skin layer 11 of the present embodiment also has a function as a layer for suppressing blocking. When the seat 10 of the present embodiment is configured to be wound in a roll shape, the seat 10 is easy to manufacture and easy to handle.

Example

[0072] Next, the above embodiment will be described more specifically by giving examples and comparative examples. 1. Fabrication of Seat First, as the polyurethane film of the example, a film of polyester-based polyurethane (manufactured by Seiko Chemical Co., Ltd., Luxskin U2245) was prepared. The thickness of the polyurethane film was 0.004 mm. The specific gravity of the polyurethane film was 1.1 g / cm 3 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 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.) Thickener: 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: Ferric acetylacetonate (manufactured by Nippon Chemical Industry Co., Ltd., Narsem Ferric) Isocyanate: Polymeric MDI (manufactured by BASF INOAC Polyurethane Co., Ltd., Foamlite 500B)

[0074]

Table 1

[0075] The sheets of the examples were 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 69% to 77% by volume. Then, the mixed raw materials were supplied onto the above-mentioned polyurethane film that was continuously supplied, and heat-cured at 120°C to 200°C. In this way, a sheet in which an epidermal layer composed of a polyurethane film and a foamed layer composed of a polyurethane foam were laminated was obtained.

[0076] The sheets of the comparative examples were produced as follows. The foamed layer was obtained in the same manner as the foamed layer of the examples, except that a mold-releasing substrate was used instead of the polyurethane film. After removing the mold-releasing substrate, 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 a polyurethane foam was obtained.

[0077] In the sheet of the comparative example thus obtained, the coating layer is exposed on the side opposite to the epidermal layer, while in the sheet of the example, the foamed layer is exposed on the side opposite to the epidermal layer. The sheet of the comparative example is mainly subjected to a UV coat for the purpose of suppressing blocking. In other words, the fact is that the coating layer cannot be abolished for reasons of production and handling in the sheet of the comparative example. On the other hand, the sheet of the example can suppress blocking by the epidermal layer of the polyurethane film and does not have a coating layer.

[0078] 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.

[0079] 3. Observation of the sheet The cross-section of the sheet of the example was observed using a microscope. The observation image of the cross-section of the sheet is shown in Fig. 2. When the cross-section of the polyurethane film was observed over 1200 μm, no pores were observed. Such a polyurethane film is excellent in cleaning property. Also, when the cross-section of the polyurethane foam was observed, substantially spherical cells were observed. The cell size had high uniformity. A polyurethane foam having such cells is excellent in shock absorbency.

[0080] 4. Evaluation Next, for the obtained sheets of the examples and comparative examples, the surface Taber abrasion loss (mg), the back surface static friction coefficient, and the Gurley air permeability (seconds / 100 mL) were evaluated under the following conditions. In the examples, the 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 surface and the back surface. The results are shown in Table 2.

[0081] [Abrasion loss of the surface] It was measured under the conditions of abrasion wheel H-22, rotation speed 60 rpm, load 250 g, and number of rotations 1000 according to JIS K7204. Each condition was appropriately specified according to the material of the sheet. [Static friction coefficient of the back surface] It was measured in an atmosphere of temperature 23°C and relative humidity 50% according to JIS K7125. [Gurley air permeability] It was determined according to the air permeability measurement B method (Gurley method) defined in JIS L1096:2010 8.26.2. The compression amount was 50% and the range was 100 mL. In the examples, since it exceeded 300 seconds / 100 mL, the measurement was interrupted and marked as "―" in Table 2.

[0082]

Table 2

[0083] As shown in Table 2, it was found that the wear amount of the film surface in the examples was smaller than that in the comparative examples, and the wear resistance was excellent. Also, it was found that the static friction coefficient of the foam surface in the examples was larger than that in the comparative examples, and the grip property was excellent. Furthermore, it was suggested that the examples had almost no air permeability and excellent cleaning property.

[0084] 5. Effects of the Examples According to the above examples, it is possible to provide a sheet having high wear resistance and impact absorbency, and a method for manufacturing a sheet having high wear resistance and impact absorbency.

[0085] The present disclosure is not limited to the embodiments described in detail above, and various modifications or changes are possible within the scope shown in the claims of the present disclosure.

Explanation of Signs

[0086] 10 … Sheet 10A… Surface (surface on the skin layer side) 10B… Back surface (surface on the foam layer side) 11 … Skin layer 11A… Concavo-convex shape 11P… Film 12 … Foam layer 13 … Base material 30 … Manufacturing apparatus 31 … Mixing section 32 … Roll mechanism 33 … Supply roll 34 … Product recovery roll 35 … Discharge nozzle 36 … Thickness regulating section 38 … Heating section 39 … Base material recovery roll

Claims

1. An epidermal layer composed of a polyurethane film, and a foam layer composed of a polyurethane foam, and the average cell diameter of the polyurethane foam is 50 μm or more and 300 μm or less, a sheet satisfying the following (2). (2) The polyurethane foam uses polyols including polymer polyol and polyether polyol as raw materials, when the total amount of the polyols in the raw materials is 100 parts by mass, the content of the polymer polyol in the raw materials is 50 parts by mass or more, when the total amount of the polyols in the raw materials is 100 parts by mass, the content of the polyether polyol in the raw materials is 16 parts by mass or less

2. An epidermal layer composed of a polyurethane film, and an installation layer composed of a polyurethane foam, and a sheet satisfying the following (1). (1) The polyurethane film has a thickness of 0.010 mm or less, the polyurethane foam is a polyurethane foam using a mixed raw material containing polyols and polyisocyanates, and as the polyols, it includes a first polyol composed of polymer polyol and a second polyol composed of polyether polyol, when the total amount of the polyols in the mixed raw materials is 100 parts by mass, the content of the first polyol in the mixed raw materials is 50 parts by mass or more, when the total amount of the polyols in the mixed raw materials is 100 parts by mass, the content of the second polyol in the mixed raw materials is 16 parts by mass or less

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