Composite sheet

Abstract

To provide a composite sheet which has a good texture, can be provided at a lower cost compared with conventional synthetic leather, hardly leaves wrinkles when folded, and is easy to follow even a structure of a complicated shape.SOLUTION: A composite sheet (100) has a skin layer (10) and a slab urethane foam layer (20), with the average thickness of the slab urethane foam layer (20) being 1.5 mm or more. The composite sheet is configured such that no base fabric is provided between the skin layer (10) and the slab urethane foam layer (20).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite sheet in which a resin surface layer is supported on a urethane foam layer. [Background technology]

[0002] Synthetic leather is widely used as a substitute for genuine leather from the standpoint of cost reduction and animal welfare. As shown in Patent Document 1, such synthetic leather is composed of a base fabric made of a fabric such as a woven, knitted, or nonwoven fabric, and a surface layer laminated on the surface of the base fabric.

[0003] The above-mentioned surface layer is a resin layer composed of a base resin such as polyurethane resin or vinyl chloride resin, and the base fabric is a layer that serves as a foundation to support the above-mentioned resin layer. The base fabric is an aggregate of fibers and is excellent in that it is stiff and can firmly support the surface layer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-228258 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, conventional synthetic leather had the following problems. Specifically, because conventional synthetic leather has a stiff base fabric, creases that occur when folded tend to remain, and wrinkles can occur in the surface layer. In addition, when conventional synthetic leather is laminated to the outer surface of a complex-shaped structure, the synthetic leather does not conform well to the outer surface in areas with sharp angles or uneven surfaces, making it difficult to laminate neatly. Furthermore, there was a demand for a sheet that could be used as a substitute for genuine leather while achieving further cost reduction.

[0006] This invention has been made in view of the above-mentioned problems. Specifically, the object of this invention is to provide a composite sheet that has a good texture, can be provided at a lower cost compared to conventional synthetic leather, does not retain wrinkles when folded, and can easily conform to the outer surface of complexly shaped components. [Means for solving the problem]

[0007] The composite sheet of the present invention Made of a resin layer It has a surface layer and a slab urethane foam layer, and the average thickness of the slab urethane foam layer is 1.5 mm or more. The 40% compression hardness of the above slab polyurethane foam layer is 250N or higher, and the density of the above slab polyurethane foam layer is 30 kg / m³. 3 More than 70kg / m 3 The following: This product is characterized by the absence of a base fabric between the above-mentioned surface layer and the above-mentioned slab urethane foam layer. [Effects of the Invention]

[0008] The composite sheet of the present invention having the above configuration is a composite sheet that has a good texture and can be provided at low cost, is less prone to wrinkles when folded, and can easily conform to the outer surface of complexly shaped components. [Brief explanation of the drawing]

[0009] [Figure 1] This is a conceptual diagram showing a cross-section of synthetic leather, which is the first embodiment of the present invention. [Figure 2] This is a conceptual diagram showing a cross-section of synthetic leather, which is a second embodiment of the present invention. [Figure 3] This is a conceptual diagram showing a cross-section of conventional synthetic leather. [Modes for carrying out the invention]

[0010] [First Embodiment] Hereinafter, the composite sheet 100 of the first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a conceptual diagram showing a cut surface formed by cutting the composite sheet 100 which is the first embodiment of the present invention in the thickness direction. Also, as a comparison with the first embodiment, the conventional synthetic leather will be described as appropriate with reference to FIG. 3. FIG. 3 is a conceptual diagram showing a cut surface formed by cutting the synthetic leather 20 shown as an example of the prior art in the thickness direction.

[0011] As shown in FIG. 1, the composite sheet 100 of the present embodiment has an epidermis layer 10 and a slab urethane foam layer 20. Although no base fabric is provided between the epidermis layer 10 and the slab urethane foam layer 20, the average thickness of the slab urethane foam layer 20 is 1.5 mm or more, whereby the epidermis layer 10 is firmly supported. Therefore, although the composite sheet 100 does not have a base fabric between the epidermis layer 10 and the slab urethane foam layer 20, it can be applied to various uses as a substitute for genuine leather or conventional synthetic leather. Generally, since the urethane foam sheet constituting the slab urethane foam layer 20 can be prepared at a lower price than the base fabric used for synthetic leather, the composite sheet 100 can reduce costs compared to conventional synthetic leather. Also, since the composite sheet 100 supports the epidermis layer 10 by the slab urethane foam layer 20 instead of a base fabric, it exhibits excellent effects due to the characteristics of the slab urethane foam layer 20.

[0012] The average thickness of the composite sheet 100 in the present embodiment is not particularly limited, but for example, it is preferably 1.6 mm or more and 12 mm or less, and more preferably 1.6 mm or more and 10 mm or less. The average thickness of the composite sheet 100 is obtained by actually measuring the thicknesses of several randomly selected locations (for example, 10 locations) in the composite sheet 100 and calculating the average value. The adjustment of the average thickness of the composite sheet 100 is performed by appropriately adjusting the thicknesses of each layer constituting the composite sheet 100, but it is preferable to appropriately adjust the thickness of the layer showing the maximum thickness among the layers constituting the composite sheet 100.

[0013] [Epidermis layer] The surface layer 10 is a resin layer capable of exhibiting the texture of genuine leather, and can be constructed in the same way as the surface layer in conventional synthetic leather. More specifically, the surface layer 10 can be constructed by including, for example, a polyurethane resin or a vinyl chloride resin as a base resin. In the present invention, the base resin refers to a resin that is included in the resin constituting the surface layer 10 in an amount exceeding 50% by mass. The surface layer 10 is a layer that constitutes the surface or near the surface of the composite sheet 100. In this embodiment, the surface layer 10 is provided on the outermost surface of one side of the composite sheet 100, but for example, another layer (for example, a surface protection layer not shown) may be provided on the side of the surface layer 10 opposite to the slab urethane foam layer 20.

[0014] In the surface layer constituent resin constituting the surface layer 10, the content ratio of base resins such as polyurethane resin and / or vinyl chloride resin is not particularly limited, but in 100% by mass of the surface layer constituent resin, the content ratio of base resins such as polyurethane resin and / or vinyl chloride resin is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably substantially 100% by mass.

[0015] The polyurethane resin used as the base resin in the surface layer 10 can be appropriately selected from polyurethane resins capable of forming the surface layer of synthetic leather. Specifically, examples of the polyurethane resins include polyester polyurethane resins, polyether polyurethane resins, polycaprolactone polyurethane resins, polyester / polyether copolymer polyurethane resins, polyamino acid / polyurethane copolymer resins, and non-yellowing polycarbonate polyurethane resins obtained by reacting a polycarbonate diol component with a non-yellowing diisocyanate component and a low molecular weight chain extender. Furthermore, polyvinyl chloride resin or synthetic rubber may be mixed with the polyurethane resins as long as it does not impair the various physical properties of the synthetic leather. The polyurethane resin contained in the surface layer 10 may be one type or two or more types.

[0016] Furthermore, the vinyl chloride resin used as the base resin in the surface layer 10 refers to a resin containing structural units derived from vinyl chloride, and can be appropriately selected from vinyl chloride resins capable of forming the surface layer of synthetic leather. Specifically, examples of the vinyl chloride resin include a homopolymer of vinyl chloride, a copolymer using a vinyl chloride monomer and other monomers copolymerizable thereto, or a blend of these resins. Other monomers copolymerizable with the above-mentioned vinyl chloride monomers include, for example, ethylene, propylene, vinyl acetate, vinylidene chloride, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, maleic acid, and acrylonitrile fumarate. Furthermore, polyurethane resins or synthetic rubbers may be mixed with the above-mentioned vinyl chloride resin, as long as the physical properties of the synthetic leather are not impaired. The vinyl chloride resin contained in the surface layer 10 may be one type or two or more types.

[0017] When a vinyl chloride resin is used as the base resin in the surface layer 10, a plasticizer may be added together with the vinyl chloride resin to more effectively exhibit flexibility similar to that of natural leather. Examples of plasticizers include general phthalate ester plasticizers such as dioctyl phthalate (DOP), diisononyl phthalate (DINP), butyl benzyl phthalate (BBP), diisodecyl phthalate (DIDP), and diundecyl phthalate (DUP); general fatty acid ester plasticizers such as dioctyl adipate (DOA), dioctyl sebacate (DOS), and dioctyl azelaate (DOZ); polymeric plasticizers such as trioctyl trimellitate plasticizers and adipic acid polyester plasticizers such as polypropylene adipate; sebacate plasticizers; and phosphate ester plasticizers such as tricresyl phosphate (TCP), trixylenyl phosphate (TXP), tris(isopropylphenyl) phosphate, tributyl phosphate, triethyl phosphate, triphenyl phosphate, and triethylphenyl phosphate.

[0018] The thickness of the epidermal layer 10 is not particularly limited, but it is preferably formed to a thickness of 10 μm to 500 μm, and more preferably to a thickness of 10 μm to 400 μm. The thickness of the epidermal layer 10 is obtained by measuring the thickness of the epidermal layer 10 at multiple randomly selected locations (for example, 10 locations) on the cross-section of the composite sheet 100 observed with a microscope, and then taking the arithmetic mean of these measured values.

[0019] Other additives: In addition to the resin and plasticizer, the surface layer 10 may contain additives as appropriate, without departing from the spirit of the present invention. Examples of such additives include defoaming agents, defoaming agents, stabilizers, fillers, flame retardants, and pigments.

[0020] Incidentally, the composite sheet 100 may have a textured or embossed pattern, etc., which can be observed when the surface layer 10 is examined. Here, "texture" refers to irregular bumps and dips on the surface side of the surface layer 10, and "pattern" refers to decorative patterns, designs, etc., on the surface side of the material. Since the composite sheet 100 has a slab urethane foam layer 20 with a thickness of 1.5 mm or more, when embossing is applied from the surface layer 10 side, recesses can be firmly formed not only on the surface layer 10 but also on the slab urethane foam layer 20. Therefore, compared to conventional synthetic leather, the composite sheet 100 can form deep and clear patterns, etc., and has superior design appeal.

[0021] [Slab urethane foam layer] The slab urethane foam layer 20 is a layer that supports the surface layer 10 described above, and is laminated to the surface layer 10 directly or indirectly. In this embodiment, it is laminated to the surface layer 10 via an adhesive layer 30, but for example, the adhesive layer 30 may be omitted and the slab urethane foam layer 20 may be laminated directly to the surface layer 10. In this invention, the slab urethane foam layer 20 refers to a layer made of urethane foam with an average thickness of 1.5 mm or more, and capable of supporting the surface layer 10. From the viewpoint of better solving the intended problems of this invention, the average thickness of the slab urethane foam layer 20 is preferably 1.6 mm or more, and more preferably 1.7 mm or more. On the other hand, the upper limit of the average thickness can be appropriately determined depending on the application of the composite sheet 100, but from the viewpoint of keeping costs down while sufficiently satisfying the problems of being less prone to wrinkling and conforming well to the outer surface of articles with complex shapes, it is preferably 10 mm or less, and more preferably 8.0 mm or less. On the other hand, the base fabric, which is contrasted with this, refers to a fabric made of fibers such as woven, knitted, or nonwoven fabrics. The thickness of the base fabric is not particularly limited, but in general synthetic leather, a base fabric with a thickness of about 0.5 mm to 2.0 mm is commonly used.

[0022] The average thickness of the slab polyurethane foam layer 20 is obtained by measuring the thickness of the slab polyurethane foam layer 20 at multiple randomly selected locations (for example, 10 locations) on the cross-section of the composite sheet 100 observed with a microscope, and then taking the arithmetic mean of these measured values.

[0023] As mentioned above, conventional synthetic leather had the problem of easily retaining wrinkles when folded or otherwise processed. This was presumed to be because the fibers constituting the base fabric would break when folded, and that condition would persist. On the other hand, the composite sheet 100 exhibits the excellent effect of being less prone to retaining wrinkles when folded or otherwise processed. This was presumed to be due to the self-restoring properties of the slab urethane foam layer 20 having a thickness of 1.5 mm or more.

[0024] Furthermore, conventional synthetic leather had the problem of being difficult to conform to the outer surface of items with complex shapes. This was presumed to be due to the stiffness of the base fabric. On the other hand, when a composite sheet 100 comprising a slab urethane foam layer 20 having a thickness of 1.5 mm or more is laminated to the outer surface of an article with a complex shape, by sufficiently pressing the composite sheet 100 against the complex shape, some of the air bubbles in the urethane foam constituting the slab urethane foam layer 20 are crushed, thereby allowing the composite sheet 100 to conform perfectly to the complex shape. As a result, the composite sheet 100 exhibits excellent conformability to the outer surface of an article with a complex shape.

[0025] The slab urethane foam layer 20 is a foamed resin layer containing a urethane-based resin as the base resin. In the 100% by mass of the slab urethane foam layer constituent resin that makes up the slab urethane foam layer 20, it is preferable that the urethane-based resin accounts for 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass or more.

[0026] The urethane resin contained in the slab urethane foam layer 20 can be appropriately selected from the same resins as those contained in the surface layer 10 described above. The means for foaming the urethane resin in the slab urethane foam layer 20 are not particularly limited and include physical foaming by mechanical stirring, chemical foaming by adding a foaming agent, and pseudo-foaming by adding hollow fine particles. Generally, a polyurethane foam can be formed by reacting an isocyanate group with water, a blowing agent, to generate carbon dioxide, and then reacting the isocyanate with a polyol to cure it, thereby incorporating carbon dioxide into the urethane resin.

[0027] Incidentally, since the slab urethane foam layer 20 is a foamed layer with an average thickness of 1.5 mm or more, it has moderate flexibility and provides a good feel and cushioning in the composite sheet 100. However, air bubbles in the slab urethane foam layer 20 may be visible as minute irregularities on the surface of the surface layer 10. Such air bubbles can be eliminated, for example, by designing the surface layer 10 to be sufficiently thick. In addition to adjusting the thickness of the surface layer 10, from the viewpoint of avoiding the occurrence of such air bubbles and providing a composite sheet 100 with a more beautiful appearance, it is preferable that the 40% compression hardness of the slab urethane foam layer 20 be 250 N or more, more preferably 300 N or more, and even more preferably 350 N or more. From the viewpoint of improving the appearance of the composite sheet 100, there is no particular upper limit to the 40% compression hardness of the slab urethane foam layer 20. However, from the viewpoint of maintaining appropriate flexibility, it is preferable that the upper limit of the 40% compression hardness be 800N or less. Furthermore, if the 40% compression hardness of the slab urethane foam layer 20 is 250N or more, there is the advantage that wrinkles are less likely to form on the surface of the composite sheet 100 during the manufacturing of the composite sheet 100, as described later. The 40% compression hardness of the slab polyurethane foam layer 20 is measured in accordance with JIS K6400-2A method:2012.

[0028] Furthermore, as a different means of improving the appearance of the composite sheet 100, the density of the slab urethane foam layer 20 is 30 kg / m³. 3 Preferably, it is 33 kg / m 3 It is more preferable that the above conditions are met. From the viewpoint of improving the appearance of the composite sheet 10, there is no particular upper limit to the density of the slab urethane foam layer 20; however, from the viewpoint of maintaining appropriate flexibility, the above upper limit of density is 70 kg / m³. 3 The following is preferable: The density of the slab polyurethane foam layer 20 is measured in accordance with JIS K7222:2005.

[0029] Furthermore, since the slab urethane foam layer 20 is composed of foamed polyurethane, when an adhesive layer 30 is formed on one side of the slab urethane foam layer 20 as in this embodiment, the adhesive constituting the adhesive layer 30 can adequately impregnate the air bubbles contained in the slab urethane foam layer 20, resulting in good adhesion. From the viewpoint of ensuring sufficient adhesion, the air permeability of the slab urethane foam layer 20 should be 5 ml / cm². 2 It is preferable that the value be / s or higher.

[0030] However, it is desirable to note that depending on the size and connectivity of the air bubbles contained in the slab urethane foam layer 20, the adhesive may penetrate too deeply, which may actually reduce the adhesion between the slab urethane foam layer 20 and the surface layer 10. In embodiments in which the slab urethane foam layer 20 is laminated directly or indirectly to the surface layer 10 by the adhesive layer 30, from the viewpoint of taking sufficient care to prevent the aforementioned reduction in adhesion, the air permeability of the slab urethane foam layer 20 should be 50 ml / cm². 2 It is preferable that the rate is less than or equal to 40 ml / cm³. 2 It is more preferable that the value be less than or equal to / s.

[0031] The air permeability of the slab polyurethane foam layer 20 described above is measured in accordance with JIS-L1096:2020.

[0032] From the viewpoint of avoiding the appearance of air bubble marks constituting the slab urethane foam layer 20 on the surface of the skin layer 10 and meeting the demand for cost reduction, it is preferable that in the composite sheet 100, the total thickness of the layers other than the slab urethane foam layer 20 (in this embodiment, the sum of the thickness of the skin layer 10 and the thickness of the adhesive layer 30) is 100 μm or more and 500 μm or less.

[0033] Furthermore, the physical properties of the slab urethane foam layer 20 described above are due to the physical properties of the urethane foam used to constitute the slab urethane foam layer 20. Therefore, by selecting a urethane foam whose physical properties, such as 40% compression hardness, density, or air permeability, are within the preferred range described above, and using this to construct the slab urethane foam layer 20, a composite sheet 100 can be obtained that has a slab urethane foam layer 20 exhibiting the preferred range of 40% compression hardness, density, or air permeability described above. Furthermore, when confirming the physical properties of the slab urethane foam layer 20 constituting the composite sheet 100, a measurement sheet may be prepared by cutting out the slab urethane foam layer 20 from the composite sheet 100, and this measurement sheet may be used to measure each physical property. When preparing the above measurement sheet, it is preferable to cut out the slab urethane foam layer 20 while avoiding the interface between the slab urethane foam layer 20 and the adjacent layer.

[0034] [Adhesive layer] The adhesive layer 30 is provided between the slab urethane foam layer 20 and the surface layer 10, and is a layer for directly or indirectly bonding the slab urethane foam layer 20 and the surface layer 10. In this embodiment, the adhesive layer 30 directly bonds the slab urethane foam layer 20 and the surface layer 10. The adhesive constituting the adhesive layer 30 can be appropriately selected from adhesives used to form the layer structure of conventional synthetic leather. For example, typical adhesives include vinyl chloride resin adhesives and polyurethane resin adhesives. The vinyl chloride resin contained in the vinyl chloride resin adhesive or the polyurethane resin contained in the polyurethane resin adhesive is the same resin as the resin constituting the surface layer 10 described above, so specific examples are omitted here.

[0035] In the adhesive layer 30, the content ratio of vinyl chloride resin in the vinyl chloride resin adhesive or polyurethane resin in the polyurethane resin adhesive is not particularly limited. However, from the viewpoint of suppressing the manufacturing cost of the composite sheet 100, it is preferable that the content ratio of vinyl chloride resin or polyurethane resin in 100% by mass of the resin constituting the adhesive layer 30 be 90% by mass or more, more preferably 95% by mass or more, and even more preferably substantially 100% by mass.

[0036] The adhesive layer 30, which is composed of a vinyl chloride resin adhesive, may contain other resins in addition to the vinyl chloride resin. As the other resins, one or more can be selected from resins usable as adhesives, such as polyurethane resins or polyolefin resins. Similarly, the adhesive layer 30, which is composed of a polyurethane resin adhesive, may contain other resins in addition to the polyurethane resin. As other resins, one or more can be selected from resins that can be used as adhesives, such as vinyl chloride resins or polyolefin resins.

[0037] Furthermore, from the viewpoint of adhesion between the epidermal layer 10 and the adhesive layer 30, if the epidermal layer 10 is composed of a polyurethane resin as the base resin, it is preferable that the adhesive layer 30 be composed of a polyurethane resin adhesive, and if the epidermal layer 10 is composed of a vinyl chloride resin as the base resin, it is preferable that the adhesive layer 30 be composed of a vinyl chloride resin adhesive.

[0038] Generally, the adhesive layer 30 is formed by coating one of the opposing layers with an adhesive resin composition via the adhesive layer 30, and then laminating the other layer. The coating thickness of the adhesive resin composition is not particularly limited, but it is preferably 60 μm or more and 300 μm or less relative to the coated surface.

[0039] Plasticizer: When the adhesive layer 30 is composed of a vinyl chloride resin adhesive, it is preferable to use a plasticizer together with the vinyl chloride resin. That is, the adhesive layer 30 is preferably composed of an adhesive resin composition containing a vinyl chloride resin and a plasticizer. In the adhesive layer 30, it is preferable that the plasticizer is contained in an amount of 80 parts by mass or more and 110 parts by mass or less per 100 parts by mass of the vinyl chloride resin contained in the adhesive layer 30. Examples of plasticizers include ester-based plasticizers having ester bonds in the molecule. Examples of ester-based plasticizers include, but are not limited to, phthalate-based ester plasticizers, adipic acid-based ester plasticizers, sebaciate-based ester plasticizers, maleic acid-based ester plasticizers, etc. Examples of plasticizers other than ester-based plasticizers include trimellitic acid-based plasticizers and phosphate-based plasticizers. From the viewpoint of versatility, phthalate-based ester plasticizers are preferred.

[0040] The composite sheet 100 of this embodiment has been described above, with appropriate comparisons to conventional synthetic leather. Incidentally, in conventional synthetic leather, the configuration shown in Figure 3 is sometimes adopted. Figure 3 is a conceptual diagram showing a cross-section created by cutting conventional synthetic leather 200 in the thickness direction. The synthetic leather 200 comprises a surface layer 10 and a base fabric 201 laminated together via an adhesive layer 30, and further comprises a cushion layer 202 on the side of the base fabric 201 opposite to the surface layer 10. Here, the cushion layer 202 may be made of urethane foam, similar to the slab urethane foam layer 20 described above. While the cushioning properties of the synthetic leather 200 can be improved by adding a cushioning layer 202 to the base fabric 201, the presence of the base fabric 201 between the surface layer 10 and the cushioning layer 202 means that wrinkles caused by bending and other actions tend to remain in the synthetic leather 200, resulting in the same problems as synthetic leather without the cushioning layer 202. In other words, the conventional synthetic leather 200 shown in Figure 3 does not suggest that the presence of the cushioning layer 202 solves these problems.

[0041] [Second Embodiment] Next, a composite sheet 120, which is a second embodiment of the present invention, will be described with reference to Figure 2. Figure 2 is a conceptual diagram showing a cross-section formed by cutting the composite sheet 120, which is a second embodiment of the present invention, in the thickness direction. The composite sheet 120 differs from the composite sheet 100 described above in that it has a foam layer 40 between the surface layer 10 and the adhesive layer 30, and that a backing fabric 50 and a surface protection layer 60 are provided on the side of the slab urethane foam layer 20 opposite to the surface layer 10, but is otherwise configured similarly. In this embodiment, the slab urethane foam layer 20 and the surface layer 10 are indirectly laminated via the adhesive layer 30. In this embodiment, the configuration of the composite sheet 120 will be described mainly in terms of its differences from that of the composite sheet 100, and the configuration common to the composite sheet 100 will be described as appropriate by referring to the description in the first embodiment.

[0042] [Foam layer] The composite sheet 120 of this embodiment includes a foamed layer 40 between the surface layer 10 and the adhesive layer 30. The foamed layer 40 is a foamed resin layer composed of a vinyl chloride resin or a polyurethane resin as the base resin, and has multiple air bubbles within the layer. By incorporating the foam layer 40, the composite sheet 100 can exhibit superior texture and flexibility. Furthermore, the foam layer 40 has the effect of mitigating surface irregularities of the slab urethane foam layer 20, resulting in a good appearance of the composite sheet 10 even if the thickness of the layers other than the slab urethane foam layer 20 is relatively small.

[0043] The content ratio of vinyl chloride resin or polyurethane resin in the foamed layer 40 is not particularly limited, but it is preferable that the content ratio of vinyl chloride resin or polyurethane resin in 100% by mass of the foamed layer constituent resin constituting the foamed layer 40 be 90% by mass or more, more preferably 95% by mass or more, and even more preferably substantially 100% by mass. If the content ratio of vinyl chloride resin or polyurethane resin in 100% by mass of the foamed layer constituent resin is less than 100% by mass, any other resin may be further included as the remaining resin. The vinyl chloride resin, polyurethane resin, and other resins used as the constituent resin of the foam layer are the same as those used for the surface layer 10 described above, so a detailed explanation is omitted here. The vinyl chloride resin or polyurethane resin that constitutes the foam layer 40 may be the same as or different from the resin that constitutes the surface layer 10 and / or the adhesive layer 30. Furthermore, the foamed layer 40 may contain a plasticizer in addition to the resin described above. The plasticizer contained in the foamed layer 40 is the same as that used in the adhesive layer 30 described above, so a detailed explanation is omitted here. However, the plasticizer used in the foamed layer 40 may be the same as the plasticizer used in the adhesive layer 30, or it may be different.

[0044] When the foam layer 40 is mainly composed of a vinyl chloride resin, the foaming agent is appropriately selected from foaming agents commonly used when forming foamed resins using vinyl chloride resins. For example, specific examples of foaming agents include, but are not limited to, sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, sodium borohydride, calcium azide, azodicarbonamide, azobisisobutyronitrile, barium azodicarboxylate, N,N'-dinitropentamethylenetetramine, p,p'-oxybis(benzenesulfonyl hydrazide), p-toluenesulfonyl hydrazide, p-toluenesulfonyl semicarbazide, and expansion beads.

[0045] Furthermore, when the foamed layer 40 is mainly composed of polyurethane resin, it may be formed by physical foaming by mechanical stirring, chemical foaming by adding a foaming agent, or pseudo-foaming by adding hollow fine particles.

[0046] The average thickness of the foam layer 40 is not particularly limited, but from the viewpoint of exhibiting good shock absorption or flexibility, it is preferable to be 100 μm or more, and from the viewpoint of manufacturing cost, it is preferable to be 500 μm or less. The average thickness of the foam layer 40 is determined by measuring the thickness of the foam layer 40 at several randomly selected locations (for example, 10 locations) in a microscope photograph of the cross-section of the composite sheet 100, and taking the arithmetic mean of the measured values.

[0047] In this embodiment, an adhesive layer 30 is provided between the foam layer 40 and the slab urethane foam layer 20. However, the adhesive layer 30 can be omitted by providing, for example, a foam adhesive layer (not shown) as a substitute for the foam layer 40. Specifically, a foam-forming resin composition is applied to the surface of the epidermal layer 10 to form a pre-foamed layer. While the pre-foamed layer is still uncured, a slab urethane foam layer 20 is placed on the pre-foamed layer, and the urethane resin in the pre-foamed layer is cured by heating, thereby forming a foam adhesive layer that adheres to the slab urethane foam layer 20.

[0048] [Lining] The composite sheet 120 has a backing fabric 50 on the side opposite to the surface layer 10 of the slab urethane foam layer 20. By providing the backing fabric 50, the slipperiness of the composite sheet 120 can be improved, thereby improving the workability of the composite sheet 120 during processing. However, if sufficient slipperiness can be ensured on the exposed surface of the slab urethane foam layer 20 without providing the backing fabric 50, or if the processing work does not particularly require slipperiness on the exposed surface of the slab urethane foam layer 20, then it is not necessary to provide the backing fabric 50.

[0049] The lining fabric 50 can be made from woven fabric, knitted fabric, or nonwoven fabric, etc. The basis weight of the lining 50 is not particularly limited, but from the perspective of significantly improving the above-described slipperiness and achieving weight reduction and cost reduction, it is preferably 10 g / m 2 or more and 100 g / m 2 or less.

[0050] [Surface protective layer] On the surface of the skin layer 10 opposite to the slab urethane foam layer 20 of the composite sheet 120, a surface protective layer 60 is provided. The surface protective layer 60 is composed of a resin or the like appropriately selected. For example, the surface protective layer 60 is composed of a polyurethane-based resin and a crosslinking agent. The surface protective layer 60 is a layer that protects the surface of the skin layer 10 and can improve the abrasion resistance and the like of the composite sheet 100. The polyurethane-based resin that can constitute the surface protective layer 60 refers to a resin containing a urethane bond in the molecule, and more specifically, a resin having a urethane bond in the repeating unit of the main chain.

[0051] The polyurethane resin constituting the surface protective layer 60 is obtained by reacting a polyol component with a polyol component, and any polyurethane resin can be used as long as it can form a layer suitable for protecting the surface side of the composite sheet 120. For example, as an example, an aqueous polyurethane resin can be mentioned. An aqueous polyurethane resin refers to a polyurethane resin having a hydrophilic group and being soluble or emulsifiable in water. Such aqueous polyurethane resins include, for example, polyurethanes having a hydrophilic group (an anionic hydrophilic group, a cationic hydrophilic group, or a nonionic hydrophilic group) in the molecule, or polyurethanes to which a hydrophilic segment is imparted. Among the aqueous polyurethane resins, a polycarbonate-based polyurethane resin is preferable from the viewpoints of durability, abrasion resistance, and hydrolysis resistance. Polycarbonate-based polyurethane can be obtained, for example, by using a polycarbonate-based diol and a polyisocyanate and subjecting them to a polyaddition reaction.

[0052] The above-mentioned crosslinking agent can be any agent that can improve the physical properties of the polyurethane resin by causing self-crosslinking or three-dimensional crosslinking of the polyurethane resin, and examples include carbodiimide-based crosslinking agents, isocyanate-based crosslinking agents, or oxazoline-based crosslinking agents.

[0053] In the surface protective layer 60 containing a polyurethane resin, the proportion of the crosslinking agent blended with 100 parts by mass of the polyurethane resin contained in the surface protective layer 60 is not particularly limited, but is preferably, for example, 2 parts by mass or more and 20 parts by mass or less. If the amount of the crosslinking agent is less than 2 parts by mass, the abrasion resistance may be insufficient, and if it exceeds 20 parts by mass, the surface protective layer 60 may harden and impair its texture.

[0054] The average thickness of the surface protective layer 60 is not particularly limited, but from the viewpoint of being able to adequately protect the surface layer, it is preferably 5 μm to 50 μm. The average thickness of the surface protection layer 60 is obtained by measuring the thickness of the surface protection layer 60 at 10 randomly selected locations on the cross-section of the composite sheet 100 observed with a microscope, and then taking the arithmetic mean of these measured values.

[0055] [Method for manufacturing composite sheets] Next, an example of a method for manufacturing the composite sheet of the present invention will be described. However, the following description does not limit the method for manufacturing the composite sheet of the present invention in any way. The synthetic leather of the present invention may be manufactured by other methods as appropriate, without departing from the spirit of the present invention.

[0056] The composite sheet of the present invention can be manufactured by a manufacturing method that includes a surface layer forming step of coating a release paper with a resin composition for forming a surface layer, a slab urethane foam layer forming step of directly or indirectly laminating a urethane foam sheet with an average thickness of 1.5 mm or more to the surface layer formed in the surface layer forming step to form a pre-composite sheet having a slab urethane foam layer, and a crimping step of passing the laminate formed in the slab urethane foam layer forming step between facing rotating rolls at a predetermined interval and crimping it in the thickness direction. For example, after the crimping step, the composite sheet can be wound up with a winding roll installed downstream of the manufacturing process. Furthermore, the method for manufacturing the composite sheet of the present invention may include, in addition to the surface layer formation step, slab urethane foam layer formation step, and compression step described above, any other appropriate steps. Specifically, the method for manufacturing a composite sheet comprising a surface layer, a foam layer, an adhesive layer, a slab urethane foam layer, and a backing fabric will be described below.

[0057] (epidermal layer formation process) A resin composition for forming an epidermal layer is prepared and applied to release paper using a doctor knife coater, comma doctor coater, or other conventional coating method, and then heated and dried as appropriate to form an epidermal layer. The resin composition for forming an epidermal layer contains an epidermal layer constituent resin including a base resin and appropriate additives.

[0058] (Foam layer formation process) Using a pre-prepared resin composition for forming a foam layer, it is applied to the exposed surface of the surface layer formed as described above by the same coating means as described above, and heated as appropriate to induce foaming and form a foam layer. The resin composition for forming a foam layer contains a foam layer constituent resin including a base resin and appropriate additives. The manner of foaming in the foam layer formation process is not particularly limited and can include physical foaming by mechanically stirring the resin composition for forming the foam layer to incorporate air, chemical foaming by adding a foaming agent, and pseudo-foaming by adding hollow fine particles.

[0059] (Adhesive layer formation process) Using a pre-prepared adhesive layer-forming resin composition, the composition is applied to the exposed surface of the foamed layer formed as described above by the same coating means as described above, and then heated and dried as appropriate to form an adhesive, semi-cured adhesive layer. The adhesive layer-forming resin composition contains an adhesive layer constituent resin including a base resin, and appropriate additives.

[0060] (Slab urethane foam layer formation process) As described above, a slab urethane foam layer is formed by laminating a pre-manufactured urethane foam sheet with an average thickness of 1.5 mm or more onto the semi-cured adhesive layer, thereby obtaining a laminate (pre-composite sheet).

[0061] (Crimping process) As described above, the resulting laminate (pre-composite sheet) is passed between opposing rolls spaced at a predetermined interval and pressed in the thickness direction to obtain a pre-composite sheet. By adjusting the distance between these rolls, the amount of penetration thickness of the adhesive layer-forming resin composition into the slab urethane foam layer can be adjusted.

[0062] (Lamination process of the backing fabric) The pre-composite sheet obtained through the above-described compression process is rolled up and cured, the release paper is peeled off the pre-composite sheet, the exposed side of the slab urethane foam layer is heated and melted, and the backing fabric is laminated and bonded to produce the composite sheet.

[0063] Furthermore, the manufacturing method described above may be modified or new steps added as appropriate to obtain the composite sheet of the present invention. For example, a laminated sheet can be formed by pre-laminating a backing fabric onto a urethane foam sheet using a frame lamination method, and this can be used in the slab urethane foam layer formation process. In this case, the backing fabric lamination step after the compression step is omitted. The frame lamination method referred to here is a lamination method in which at least the surface of a soft urethane foam sheet is melted to laminate and bond the backing fabric. Alternatively, by forming a semi-cured foam layer (foam adhesive layer) that exhibits adhesive properties during the foam layer formation process, and then proceeding with the slab urethane foam layer formation process, the slab urethane foam layer can be directly laminated onto the foam layer (foam adhesive layer). In this case, the adhesive layer formation process described above may be omitted as appropriate. If a surface protection layer is to be provided on the surface of the epidermal layer, a surface protection layer can be formed by applying a coating liquid for forming a surface protection layer, which contains a polyurethane resin forming composition and a crosslinking agent such as isocyanate, to the surface of the epidermal layer of the composite sheet obtained as described above, and then heating it as appropriate.

[0064] As described above, the surface (the surface facing the skin layer) of the resulting composite sheet may be given a textured surface to give it a leather-like appearance, and embossing or other processing may be applied to give it a textured pattern to enhance its design. Furthermore, if a surface protective layer is provided in the composite sheet, the embossing or other processing described above may be applied to the surface of the skin layer before forming the surface protective layer. [Examples]

[0065] Examples of the present invention are described below. In the following examples, a composite sheet having the following layers in this order—a surface layer, a foam layer, an adhesive layer, and a slab urethane foam layer—is shown as an example. A conventional synthetic leather without a slab urethane foam layer is used as a comparative example. However, the following examples do not limit the present invention in any way.

[0066] First, the materials (resin compositions) constituting each layer were prepared as follows. In addition, base materials 1 to 7 to be used as slab urethane foam layers or base fabrics were prepared as follows.

[0067] <Resin composition for forming skin layer> • Polycarbonate-based polyurethane resin (DIC Corporation's "Crisbon NY335FT"): 100 parts by mass • Dimethylformamide: 30 parts by mass • Ethyl acetate: 10 parts by mass • Black pigment: 3 parts by mass <Resin composition for forming foamed layer> • Isocyanate-terminated prepolymer: 100 parts by mass • Polyether polyol: 12.5 parts by mass • Ethyl acetate: 25 parts by mass <Resin composition for forming adhesive layer> • Polycarbonate-based polyurethane resin (DIC Corporation's "Crisbon TA205FT"): 100 parts by mass • Isocyanate compound (DIC Corporation's "Barnock DN950"): 12 parts by mass • Dimethylformamide: 30 parts by mass Methyl ethyl ketone: 30 parts by mass • DIC Corporation's "Crisbon Accel T81-E": 1 mass part

[0068] <Base material> (Base material 1) Density: 45kg / m 3 40% compression hardness: 430N, air permeability: 32ml / cm² 2 / s polyurethane foam, average thickness 2mm (Base material 2) Density: 50kg / m 3 40% compression hardness: 450N, air permeability: 14ml / cm² 2 / s polyurethane foam, average thickness 2mm (Base material 3) Density: 35kg / m 3 40% compression hardness: 390N, air permeability: 9ml / cm² 2 / s polyurethane foam, average thickness 2mm (Base material 4) Density 40kg / m 3 40% compression hardness 270N, air permeability 64 ml / cm² 2 / s polyurethane foam, average thickness 2mm (Base material 5) Density: 45kg / m 3 40% compression hardness: 430N, air permeability: 32ml / cm² 2 / s polyurethane foam, average thickness 5mm (Base material 6) Density 25kg / m 3 40% compression hardness: 300N, air permeability: 13ml / cm² 2 / s polyurethane foam, average thickness 2mm (Base material 7) Polyester tricot knit fabric made from 84dtex polyester yarn, average thickness 0.8mm Furthermore, the densities of base materials 1 to 6 were measured in accordance with JIS K7222:2005, the 40% compression hardness was measured in accordance with JIS K 6400-2A method:2012, and the air permeability was measured in accordance with JIS-L1096:2020.

[0069] (Example 1) A resin composition for forming a surface layer was applied to release paper with a deep, textured surface using a comma coater. The temperature was gradually increased from 80°C to 120°C, and after reaching 120°C, it was dried for 5 minutes to obtain a surface layer with a thickness of approximately 30 μm. Next, a foam layer-forming resin composition was stirred at a speed of 1500 rpm and mixed with 1.0% air at 25°C by volume, which was then applied to the exposed side surface of the obtained surface layer. The mixture was dried at 150°C for 1 minute to obtain a foam layer with a thickness of approximately 280 μm. Then, an adhesive layer-forming resin composition was applied to the exposed side of the foamed layer using a comma coater and dried at 120°C to obtain an adhesive layer with a thickness of approximately 70 μm. At the moment the adhesive layer had developed its adhesive properties, the substrate 1 described above was unrolled and bonded onto the adhesive layer. This resulted in a laminate with a total thickness of 2380 μm. The above laminate (pre-composite sheet) was pressed together between opposing rolls (gap of 1.2 mm, clearance of approximately 50%), then wound into a roll, and matured at 50°C for 48 hours before the release paper was peeled off. This resulted in a composite sheet with the layers laminated in the following order from the surface: surface layer, foam layer, adhesive layer, and base material. The total thickness of the laminate and the thickness of each layer were similar before and after passing it between opposing rolls.

[0070] (Examples 2-6) Composite sheets were manufactured in the same manner as in Example 1, except for the change in the substrate shown in Table 1, and these were designated as Examples 2 to 6.

[0071] (Example 7) A composite sheet was manufactured in the same manner as in Example 1, except that a resin composition for forming an adhesive layer was applied to the exposed side surface of the epidermal layer and no foam layer was provided. This was designated as Example 7.

[0072] (Comparative Example 1) A multilayer sheet was manufactured in the same manner as in Example 1, except that the above-mentioned base material 7 (polyester tricot knit fabric) was used as the base material instead of polyurethane foam, and this was designated as Comparative Example 1.

[0073] (Comparative Example 2) As described above, a urethane foam sheet (density: 45 kg / m³) was applied to the exposed surface side of the base material 7 of Comparative Example 1 using a frame lamination method. 3 40% compression hardness: 430N, air permeability: 32ml / cm² 2 A multilayer sheet with a cushion layer was manufactured by laminating (2 mm) sheets (average thickness 2 mm), and this was designated as Comparative Example 2.

[0074] [evaluation] (Appearance evaluation) The surface condition of the surface layer of each example and comparative example sheet was visually inspected immediately after manufacturing (immediately after peeling off the release paper) and evaluated according to the following criteria. ◎...Good. 〇...Some wrinkles were observed, but combined with the texture transferred from the release paper, it doesn't look out of place. △···Wrinkles distinct from grain are clearly visible.

[0075] (Recovery from creases and wrinkles) Each example and comparative example sheet was cut to 5cm x 12cm, and a test specimen was prepared by folding it in half with the surface layer side as the valley, resulting in a 2.5cm x 12cm specimen. The folded test specimen was then sandwiched between acrylic plates, a load of 3000g was applied, and it was left for 24 hours to form creases. Next, the load was released, the test specimen was unfolded, and the appearance of the creases after 24 hours was examined and evaluated according to the following criteria. ○...Almost no signs of creases or folds are visible. ×...Fold marks are clearly visible.

[0076] (Surface conformability) The appearance of each example and comparative example sheet when attached to the seat surface of an automobile was observed and evaluated according to the following criteria. The seat conforms to the curved surface of the seat, resulting in a good appearance. ×...There are areas where the seat is lifting off the curved surface of the seat, resulting in a poor appearance.

[0077] [Table 1]

[0078] The above embodiment encompasses the following technical concepts. (1) Having an epidermal layer and a slab urethane foam layer, The average thickness of the aforementioned slab urethane foam layer is 1.5 mm or more. A composite sheet characterized in that there is no base fabric between the surface layer and the slab urethane foam layer. (2) The composite sheet according to (1) above, wherein the 40% compression hardness of the slab urethane foam layer is 250 N or more. (3) The density of the slab urethane foam layer is 30 kg / m³ 3 The composite sheet described in (1) or (2) above. (4) The air permeability of the slab urethane foam layer is 5 ml / cm 2 / s or later above And, The composite sheet according to any one of (1) to (3) above, wherein the slab urethane foam layer is laminated directly or indirectly to the surface layer by an adhesive layer. (5) A composite sheet according to any one of the above items (1) to (4), wherein the total thickness of the layers other than the slab urethane foam layer is 100 μm or more and 500 μm or less. (6) A method for manufacturing a composite sheet, comprising: a surface layer formation step of coating a release paper with a resin composition for forming a surface layer; a slab urethane foam layer formation step of directly or indirectly laminating a urethane foam sheet with an average thickness of 1.5 mm or more to the surface layer formed in the surface layer formation step to form a pre-composite sheet having a slab urethane foam layer; and a pressing step of passing the laminate formed in the slab urethane foam layer formation step between facing rotating rolls at a predetermined interval and pressing it in the thickness direction. [Explanation of Symbols]

[0079] 10...epidermal layer 20. Slab urethane foam layer 30...adhesive layer 40... Foam layer 50... lining 100, 120... Composite sheet 200...Synthetic leather 201...Base fabric 202...Cushion layer

Claims

1. Having a surface layer made of a resin layer and a slab urethane foam layer, The average thickness of the aforementioned slab urethane foam layer is 1.5 mm or more. The 40% compression hardness of the slab urethane foam layer is 250 N or more. The density of the slab urethane foam layer is 30 kg / m³ or more and 70 kg / m³ or less. A composite sheet characterized in that there is no base fabric between the surface layer and the slab urethane foam layer.

2. The permeability of the slab urethane foam layer is 5 ml / cm². ２ / s or greater, The composite sheet according to claim 1, wherein the slab urethane foam layer is laminated directly or indirectly to the surface layer by an adhesive layer.

3. The composite sheet according to claim 1 or 2, wherein the total thickness of the layers other than the slab urethane foam layer is 100 μm or more and 500 μm or less.

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