synthetic leather

Abstract

To provide a synthetic leather, which is made of polyvinyl chloride-based resin that is more inexpensive than polyurethane resin and has excellent flex resistance.SOLUTION: A synthetic leather (100) has a skin layer (10), fabric (20), and an adhesion layer (30) disposed between the skin layer (10) and the fabric (20). The skin layer (10) and the adhesion layer (30) contain vinyl chloride-based resin. The adhesion layer (30) is constituted so as to contain plasticizer at 80 pts.mass or more and 110 pts.mass or less to 100 pts.mass of vinyl chloride-based resin contained in the adhesion layer (30) and have 100 μm or more and 300 μm or less of impregnation thickness t1 of an adhesion resin composition comprising the adhesion layer (30) into the fabric (20).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to synthetic leather containing a vinyl chloride resin. [Background technology]

[0002] As shown in Patent Document 1, synthetic leather is composed of a fabric and a skin layer laminated on the surface of the fabric. The skin layer is a resin layer composed of a base resin. Examples of the base resin include polyurethane resin and vinyl chloride resin. Synthetic leather made using polyurethane resin has the advantage of excellent flex resistance, but is more expensive than polyvinyl chloride resin. On the other hand, vinyl chloride resin has the advantages of being inexpensive and easy to process. Therefore, synthetic leather with a skin layer made of vinyl chloride resin as a base resin is widely used in various industrial fields.

[0003] One example of the use of synthetic leather having a surface layer whose base resin is vinyl chloride resin is vehicle interior materials, particularly for vehicle seats such as automobiles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-228258 Summary of the Invention [Problem to be solved by the invention]

[0005] 4, the vehicle seat 200 is composed of a number of parts, such as a seat portion 210, a backrest portion 211, a head portion 212, a seat portion side portion 213, a backrest portion side portion 214, and a head portion side portion 215. Of these parts, the seat portion side portion 213 (particularly the seat portion side portion 213 on the getting-in / out side) has a problem in that it is prone to cracking.

[0006] This is because the seat side portions 213 are bent by a person sitting on the seat portion 210, and a large load is applied to them. In particular, in a vehicle with a high vehicle height, such as an SUV (Sport Utility Vehicle), when getting off the vehicle, the person shifts their weight from the center of the seat portion 210 to the seat side portions 213 and slides off the vehicle seat 200, which places a significant load on the seat side portions 213 when getting off the vehicle. As the number of times the vehicle is used increases, cracks are likely to occur in the synthetic leather that forms the seat side portions 213. In order to prevent the above-mentioned cracks, it is preferable to form the vehicle seat 200 using synthetic leather that uses a polyurethane-based resin that has excellent bending resistance. However, this increases the manufacturing cost.

[0007] The present invention has been made in view of the above-mentioned problems. That is, an object of the present invention is to provide a synthetic leather that uses a polyvinyl chloride resin, which is less expensive than a polyurethane resin, and that has excellent flex resistance. [Means for solving the problem]

[0008] The synthetic leather of the present invention is a synthetic leather comprising a surface layer, a fabric, and an adhesive layer provided between the surface layer and the fabric, wherein the surface layer and the adhesive layer contain a vinyl chloride resin, the adhesive layer contains a plasticizer in an amount ranging from 80 parts by mass to 110 parts by mass per 100 parts by mass of the vinyl chloride resin contained in the adhesive layer, and the penetration depth of the adhesive resin composition constituting the adhesive layer into the fabric is 100 μm to 300 μm. [Effects of the Invention]

[0009] The synthetic leather of the present invention having the above-described structure can be produced more inexpensively than synthetic leather made from polyurethane resin and has excellent flex resistance. Therefore, the synthetic leather of the present invention is suitable for use as a component for a portion that is likely to be subjected to repeated loads, such as the side of the seat cushion of a vehicle seat. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a conceptual diagram showing a cross section of a synthetic leather according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a conceptual diagram showing a cross section of a synthetic leather that is a modified example of the first embodiment. [Figure 3] 1 is a cross-sectional photograph of a synthetic leather according to an example of the present invention. [Figure 4] FIG. 1 is a perspective view of a vehicle seat. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A synthetic leather 100 according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a conceptual diagram showing a cross section obtained by cutting synthetic leather 100 according to a first embodiment of the present invention in the thickness direction. FIG. 2 is a conceptual diagram showing a cross section obtained by cutting synthetic leather 120, which is a modified example of synthetic leather 100 according to the first embodiment, in the thickness direction. FIG. 3 is a photograph of a cross section obtained by cutting synthetic leather 140 according to an example of the present invention in the thickness direction, taken at 100x magnification using a microscope (product name: VHX-5000, manufactured by Keyence Corporation). FIG. 4 is a perspective view of a vehicle seat 200. FIGS. 1 and 2 show an embodiment in which a woven fabric is used as the base material, and FIG. 3 shows an embodiment in which a stockinette knitted fabric is used as the base material. In the description of the present invention, unless otherwise specified, the vertical direction refers to the vertical direction when the synthetic leather is placed on a horizontal surface with the skin layer facing upward.

[0012] As shown in FIG. 1 , the synthetic leather 100 of the present invention comprises a surface layer 10, a fabric 20, and an adhesive layer 30 disposed between the surface layer 10 and the fabric 20. The surface layer 10 and adhesive layer 30 are layers containing a vinyl chloride resin and are constructed using an adhesive resin composition containing the vinyl chloride resin. In the synthetic leather 100 thus constructed containing a vinyl chloride resin, the adhesive layer 30 contains 80 to 110 parts by mass of plasticizer per 100 parts by mass of the vinyl chloride resin contained in the adhesive layer 30, and is configured so that the penetration depth t1 of the adhesive resin composition into the fabric 20 is 100 μm or greater. The synthetic leather 100 of this embodiment further comprises a foam layer 40 disposed between the adhesive layer 30 and the surface layer 10. However, the synthetic leather of the present invention is not limited to this embodiment and includes embodiments that do not include the foam layer 40.

[0013] The synthetic leather 100 containing vinyl chloride resin exhibits excellent flex resistance because the adhesive layer 30 contains a predetermined amount of plasticizer and the adhesive resin composition constituting the adhesive layer 30 is configured to sufficiently penetrate into the fabric 20. Therefore, the synthetic leather 100 can be fully adapted to applications requiring excellent flex resistance while keeping production costs low. The synthetic leather 100 will be described in more detail below.

[0014] [material] The fabric 20 is a layer for supporting the skin layer 10. Any fabric that is commonly used as a fabric (base fabric) for synthetic leather or artificial leather can be used as the fabric 20. Examples of the fabric 20 include knitted fabric, woven fabric, and nonwoven fabric. The knitted fabric, woven fabric, and nonwoven fabric can be made of a single fiber selected from synthetic fibers such as polyester, polyamide, polyacrylonitrile, and nylon, natural fibers such as cotton and hemp, and regenerated fibers such as rayon and acetate, or a blend of these fibers. Among these, knitted fabric and woven fabric are preferred from the viewpoint of allowing the adhesive resin composition that constitutes the adhesive layer 30 to be easily and sufficiently impregnated. In Figures 1 and 2, which explain this embodiment (synthetic leathers 100 and 120), woven fabric is shown as an example. Moreover, synthetic leather 140 shown in Fig. 3 was produced using a stockinette knitted fabric as the base material 20. The base material 20 in synthetic leather 140 is arranged with the face of the knitted fabric facing the adhesive layer 30. As can be seen from Figs. 1 to 3, the knitted fabric and woven fabric that can form base material 20 are made up of a plurality of threads, and have unevenness on the surface, which makes it easy for the adhesive resin composition to penetrate into the threads that protrude toward the adhesive layer. For example, as shown in Figures 1 and 2, a woven fabric 20 is made up of warp yarns 21 and weft yarns 22, while a knitted fabric 20 is made up of knitting yarns by an appropriate knitting technique. Generally, threads such as warp yarns, weft yarns, and knitting yarns are fiber bundles made up of numerous fibers 52. The fibers 52 can be observed, for example, in Figure 3. In the synthetic leather of the present invention, which uses a typical knitted or woven fabric as the fabric 20, the fibers 52 can be confirmed by observing the cut surface with a microscope, as shown in Figure 3. In the following explanation, Figure 3 will also be referenced as appropriate when describing the fibers 52 of the fabric 20. Note that while Figure 3 shows the cut surface observed with a microscope at 100x magnification, the magnification during observation may be adjusted as long as the fibers 52 can be confirmed.

[0015] The thickness of the fabric 20 used to form the synthetic leather 100 is not particularly limited, but from the viewpoint of easily achieving good peel strength and sufficient flex resistance, it is preferably 200 μm or more, more preferably 250 μm or more, and even more preferably 300 μm or more. Furthermore, from the viewpoint of reducing the overall weight of the synthetic leather 100 and achieving a lighter weight, the thickness of the fabric 20 is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less.

[0016] [Adhesive layer] The adhesive layer 30 is provided between the fabric 20 and the skin layer 10, and is a layer for directly or indirectly bonding the fabric 20 and the skin layer 10. In this embodiment, the adhesive layer 30 is provided between the fabric 20 and the foam layer 40, and indirectly bonds the fabric 20 and the skin layer 10 together.

[0017] PVC resin: The adhesive layer 30 is made of a material containing a vinyl chloride resin. The vinyl chloride resin refers to a resin containing structural units derived from vinyl chloride. Specific examples include a vinyl chloride homopolymer, a copolymer of a vinyl chloride monomer with another monomer copolymerizable therewith, or a blend of these resins. Examples of other monomers copolymerizable with the vinyl chloride-based monomers include ethylene, propylene, vinyl acetate, vinylidene chloride, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, maleic acid, acrylonitrile fumarate, etc. The vinyl chloride-based resin contained in the adhesive layer 30 may be one type or two or more types.

[0018] The content of vinyl chloride resin in the adhesive layer 30 is not particularly limited, but from the viewpoint of reducing the manufacturing costs of the synthetic leather 100, the content of vinyl chloride resin in 100% by mass of the resin constituting the adhesive layer 30 is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably substantially 100% by mass.

[0019] The adhesive layer 30 may contain other resins in addition to the vinyl chloride resin as described above. The other resins may be one or more selected from resins that can be used as constituent materials for adhesive layers, such as polyurethane resins or polyolefin resins.

[0020] Generally, the adhesive layer 30 is formed by applying an adhesive layer-forming coating liquid (adhesive resin composition) to one of the layers facing each other via the adhesive layer 30, and then laminating the other layer. The thickness of the adhesive layer-forming coating liquid is not particularly limited, but from the viewpoint of allowing the adhesive resin composition to easily penetrate sufficiently into the fabric 20, it is preferably 80 μm or more and 300 μm or less.

[0021] Plasticizer: The adhesive layer 30 contains a plasticizer in addition to the vinyl chloride resin described above. The adhesive layer 30 is formed using an adhesive resin composition containing a vinyl chloride resin and a plasticizer. The adhesive layer 30 contains 80 to 110 parts by mass of plasticizer per 100 parts by mass of vinyl chloride resin in the adhesive layer 30. By thus including a sufficient amount of plasticizer in accordance with the amount of vinyl chloride resin contained in the adhesive layer 30, the flex resistance of the synthetic leather 100 can be improved. From this perspective, the adhesive layer 30 preferably contains 90 or more parts by mass of plasticizer per 100 parts by mass of vinyl chloride resin, and more preferably contains 95 or more parts by mass of plasticizer.

[0022] Furthermore, from the viewpoint of more fully achieving the intended objectives of the present invention, it is preferable that the synthetic leather 100 contains 90% by mass or more of vinyl chloride resin relative to 100% by mass of the resin constituting the adhesive layer 30, and contains 80 to 110 parts by mass of plasticizer relative to 100 parts by mass of the vinyl chloride resin contained in the adhesive layer 30.

[0023] Synthetic leather containing a plasticizer may experience a phenomenon in which the plasticizer rises to the surface over time (a phenomenon known as bleed-out). For this reason, the amount of plasticizer added to synthetic leather has generally been kept to a moderate level. In contrast, the present invention makes it possible to improve the flex resistance of the synthetic leather 100 while suppressing bleed-out by incorporating a sufficient amount of plasticizer together with a vinyl chloride resin in the adhesive layer 30, which is an intermediate layer provided between the skin layer 10 and the fabric 20. Furthermore, by thoroughly permeating the fabric 20 with an adhesive resin composition containing a sufficient amount of plasticizer, the synthetic leather 100 has good peel strength and a flexible boundary region between the skin layer 10 and the fabric 20, resulting in excellent flex resistance.

[0024] The plasticizer contained in the adhesive layer 30 can be appropriately selected from plasticizers used in the production of synthetic leathers, and one type of plasticizer or a mixture of two or more types of plasticizers can be used. Specific examples of the plasticizer include ester-based plasticizers. Ester plasticizers are plasticizers that have an ester bond in the molecule, and examples of ester plasticizers include, but are not limited to, phthalic acid ester plasticizers, adipic acid ester plasticizers, sebacic acid ester plasticizers, and maleic acid ester plasticizers. Examples of plasticizers other than ester-based plasticizers include trimellitic acid-based plasticizers, phosphoric acid-based plasticizers, etc. From the viewpoint of versatility, phthalic acid-based ester plasticizers are preferred.

[0025] Penetration Thickness: As shown in FIG. 1 , in the synthetic leather 100, the adhesive resin composition constituting the adhesive layer 30 is sufficiently permeated into the substrate 20. Specifically, the permeation depth t1 is adjusted to be 100 μm or more and 300 μm or less. From the viewpoint of exhibiting better flex resistance, the permeation depth t1 is preferably 130 μm or more, more preferably 150 μm or more, and even more preferably 180 μm or more. From the viewpoint of improving flex resistance, there is no particular upper limit to the permeation depth t1, but from the viewpoint of easily obtaining a synthetic leather 100 that exhibits good peel strength, the upper limit is 300 μm or less, and preferably 280 μm or less.

[0026] In the present invention, the penetration thickness t1 refers to the vertical thickness (dimension of the thickest part) of the penetration region 50 formed by impregnating the fabric 20 with the adhesive resin composition that constitutes the adhesive layer 30. The penetration region 50 is a region where the adhesive resin composition has impregnated a portion of the fiber bundles that constitute the fabric 20 and hardened while encapsulating fibers 52 (see FIG. 3). The penetration region 50 can actually be confirmed, for example, from a photograph taken with a microscope as shown in FIG. 3. In FIG. 3, a cloudy region can be confirmed in the upper end region of the fabric 20, which is composed of fiber bundles consisting of a large number of fibers 52. This region is the penetration region 50. The penetration region 50 includes the adhesive resin composition that has impregnated the upper end of the fabric 20 and the fibers 52 encapsulated therein. Specifically, the penetration thickness t1 is determined as follows: The synthetic leather 100 is cut in the thickness direction, and the cross section is observed under a microscope (magnification 100x), and the maximum dimension is measured from the top of the area where the fibers 52 constituting the fabric 20 can be seen (i.e., the bottom of the penetration region 50) to the top of the opaque area (i.e., the top of the penetration region 50). The maximum dimension is measured for 10 penetration regions 50 that are clearly visible under the microscope, and the arithmetic mean value of the obtained measurements is defined as the penetration thickness t1.

[0027] The penetration depth t1 of the adhesive resin composition into the substrate 20 can be adjusted by any suitable means. For example, following the general method of manufacturing synthetic leather, a coating liquid for forming an adhesive layer is applied to a predetermined area (in this embodiment, the exposed surface of the foam layer 40) to create a coated surface. The substrate 20 is then placed on the coated surface to form a laminate, which is then passed between rolls to press the laminate in the thickness direction and bond the layers together. At this time, the penetration depth t1 can be adjusted by adjusting the distance (clearance) between the opposing rolls. The penetration depth t1 can also be adjusted by appropriately adjusting the viscosity of the coating liquid for forming the adhesive layer, the temperature during lamination, etc.

[0028] The fabric 20 used in this embodiment is a woven fabric, and therefore has an upper surface with unevenness formed by warp yarns 21 and weft yarns 22. In the drawing, some of the warp yarns 21 protrude upward to form convex portions, and spaces 60 are formed between the convex portions and the weft yarns 22 and the adhesive layer 30. Above this space 60, a first portion of the adhesive layer 30, which does not contain fibers 52 and is composed only of the adhesive resin composition, can be seen. As described above, the adhesive layer 30 is a layer for directly or indirectly bonding the skin layer 10 and the fabric 20, and in a photograph taken with a microscope, it appears as a cloudy, whitish region formed by the cured adhesive resin composition. Specifically, in FIG. 3, the adhesive layer 30 appears as a first portion of a cloudy, thin layer extending left and right in the plane of the drawing between adjacent penetration regions 50, and a second portion overlapping the penetration region 50.

[0029] The synthetic leather 100 of this embodiment shown in Fig. 1 and the synthetic leather 140 shown in Fig. 3 have a characteristic configuration in which the penetration region 50 protrudes above the upper surface 32 of the first portion of the adhesive layer 30, which is visible on the underside of the foam layer 40. In other words, the upper end of the penetration region 50, formed by the adhesive resin composition permeating into the fabric 20, reaches the middle of the foam layer 40. It is presumed that this characteristic configuration allows the synthetic leather 100 to exhibit good peel strength and sufficiently high flex resistance.

[0030] However, this is not the only way in which the adhesive resin composition penetrates into the fabric 20. Regarding a penetration mode different from that of this embodiment, a conceptual diagram of a cut surface of synthetic leather 120, which is a modified example of this embodiment, is shown in Figure 2. Synthetic leather 120 is similar to synthetic leather 100 in that some of the fibers 52 penetrate to the same height as the first portion of the adhesive layer 30 to form the penetration region 50. However, synthetic leather 120 differs from synthetic leather 100 in that the upper end of the penetration region 50 does not exceed the upper surface 32 of the first portion of the adhesive layer 30. Thus, the present invention encompasses any embodiment in which the penetration thickness t1 is adjusted to be 100 μm or more and 300 μm or less, regardless of the position of the upper end of the penetration region 50.

[0031] Within the scope of the present invention, the adhesive resin composition constituting the adhesive layer 30 may contain other components in addition to the vinyl chloride resin and the plasticizer.

[0032] (Foam layer) The synthetic leather 100 of this embodiment includes a foam layer 40 between the skin layer 10 and the adhesive layer 30. The foam layer 40 is a foam resin layer containing a vinyl chloride resin, and has a plurality of bubbles 41 within the layer. By providing the foam layer 40, the synthetic leather 100 can be made lighter in weight and also has flexibility and shock absorption properties that are desirable for the texture of synthetic leather.

[0033] The content of the vinyl chloride resin in the foam layer 40 is not particularly limited, but from the viewpoint of reducing the production costs of the synthetic leather 100, the content of the vinyl chloride resin in 100% by mass of the resin constituting the foam layer 40 is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably substantially 100% by mass. The vinyl chloride resin and other resins used in the foam layer 40 are similar to those in the adhesive layer 30 described above, and therefore a detailed description thereof will be omitted here. The vinyl chloride resin constituting the foam layer 40 may be the same as or different from the vinyl chloride resin constituting the adhesive layer 30.

[0034] The foam layer 40 contains a plasticizer in addition to the resin described above. From the viewpoint of further improving the flex resistance of the synthetic leather 100, it is preferable that the foam layer 40 contains 50 parts by mass or more of the plasticizer per 100 parts by mass of the vinyl chloride resin contained in the foam layer 40. On the other hand, from the viewpoint of exhibiting good flex resistance while minimizing the problem of plasticizer bleed-out, it is preferable that the foam layer 40 contains 110 parts by mass or less of the plasticizer per 100 parts by mass of the vinyl chloride resin contained in the foam layer 40. In particular, it is preferable that the content of vinyl chloride resin is 90% by mass or more in 100% by mass of the resin constituting the foam layer 40, and that the plasticizer is contained in the above-mentioned range. The amount of plasticizer per 100 parts by mass of vinyl chloride resin contained in the foam layer 40 is preferably less than the amount of plasticizer per 100 parts by mass of vinyl chloride resin contained in the adhesive layer 30. In this case, it is presumed that this has the effect of preventing bleeding out of the plasticizer.

[0035] The plasticizer used in the foam layer 40 is the same as that used in the adhesive layer 30, and therefore a detailed description thereof will be omitted here. However, the plasticizer used in the foam layer 40 may be the same as or different from the plasticizer used in the adhesive layer 30.

[0036] The foam layer 40 can be formed by applying a foam layer-forming coating liquid containing the resin, optional plasticizer, and a foaming agent to one side of the skin layer 10, followed by a treatment such as heating. The foaming agent is selected from foaming agents commonly used in forming foamed resins using vinyl chloride resins. 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(benzenesulfonylhydrazide), p-toluenesulfonylhydrazide, p-toluenesulfonylsemicarbazide, and expanded beads.

[0037] The thickness t3 of the foam layer 40 is not particularly limited, but is preferably 100 μm or more from the viewpoint of exhibiting good impact absorption or flexibility, and is preferably 500 μm or less from the viewpoint of production costs. The thickness t3 of the foam layer 40 is determined by measuring the thickness of the foam layer at 10 randomly selected points in a microscope photograph of the cut surface of the synthetic leather 100 and calculating the arithmetic average of the measured values.

[0038] (epidermal layer) The surface layer 10 is composed of a vinyl chloride resin. The surface layer 10 is a layer that forms the surface of the synthetic leather 100, and may be provided with a grain or a textured pattern as appropriate to give it a leather-like appearance. The grain here refers to irregular irregularities provided on the surface side of the surface layer 10, and the textured pattern refers to a decorative pattern, design, or the like applied to the surface side of a member. The present invention encompasses both an embodiment in which the surface layer 10 is disposed on the outermost surface of the synthetic leather 100, and an embodiment in which the surface layer 10 is disposed close to the outermost surface of the synthetic leather 110. In this embodiment, an optional layer (for example, the surface protection layer 70 described below) is disposed further surface-side than the surface layer 10.

[0039] The content of vinyl chloride resin in the skin layer 10 is not particularly limited, but from the perspective of reducing the production costs of the synthetic leather 100, the content of 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, of the 100% by mass of resin that constitutes the skin layer 10. The vinyl chloride resin and other resins used in the skin layer 10 are similar to the resin that constitutes the adhesive layer 30 described above, and therefore a detailed description thereof will be omitted here. The vinyl chloride resin that constitutes the skin layer 10 may be the same as or different from the vinyl chloride resin that constitutes the adhesive layer 30.

[0040] The degree of polymerization of the vinyl chloride resin contained in skin layer 10 is not particularly limited, but from the viewpoint of excellent flex resistance and abrasion resistance, it is preferably higher than the degree of polymerization of the vinyl chloride resin contained in foam layer 40. The relative relationship of the degrees of polymerization of the vinyl chloride resins is more preferably adjusted so that, for example, the degree of polymerization of the vinyl chloride resin contained in skin layer 10 is in the range of 1000 to 4000, and the degree of polymerization of the vinyl chloride resin contained in foam layer 40 is in the range of 600 to 2000. When skin layer 10 and foam layer 40 each contain two or more vinyl chloride resins, the above-mentioned degree of polymerization can be determined by calculating the average degree of polymerization from the blending ratio of the vinyl chloride resins used and their respective degrees of polymerization. The relative relationship of the polymerization degrees of vinyl chloride resins described above allows for the manufacture of synthetic leather 100 having a foam layer 40 by first forming the surface layer 10 on the upper surface of a release paper or the like, and then applying a foam layer-forming coating liquid to the surface layer 10 and heating it to foam, thereby preventing softening or melting of the once-hardened surface layer 10. As a result, the lower surface 14 of the surface layer 10 is formed to be substantially flat. The upper surface 12 of the surface layer 10 is generally provided with an uneven surface, such as a grained or ruffled pattern, to create the texture of synthetic leather. In contrast, by forming the lower surface 14 to be substantially flat as described above, it is possible to prevent the thickness of the surface layer 10 from becoming extremely thin in certain areas, thereby preventing the flex resistance of the synthetic leather 100 from being partially reduced.

[0041] The skin layer 10 may contain a plasticizer in addition to the resin described above. From the viewpoint of improving the flex resistance of the synthetic leather 100, it is preferable that the plasticizer be contained in an amount of 65 parts by mass or more per 100 parts by mass of the vinyl chloride resin contained in the skin layer 10. On the other hand, from the viewpoint of exhibiting good flex resistance and excellent abrasion resistance, the plasticizer is contained in an amount of preferably 90 parts by mass or less, and more preferably less than 80 parts by mass, per 100 parts by mass of the vinyl chloride resin contained in the skin layer 10. In particular, it is preferable that the vinyl chloride resin content be 90% by mass or more, and that the plasticizer content be in the above-mentioned range, per 100% by mass of the resin constituting the skin layer 10.

[0042] The plasticizer used in the skin layer 10 is the same as that used in the adhesive layer 30, and therefore will not be described in detail here. The plasticizer used in the skin layer 10 may be the same as or different from the plasticizer used in the adhesive layer 30.

[0043] Furthermore, in the synthetic leather 100, it is more preferable that the adhesive layer 30 and the skin layer 10 have the following relationship: That is, the adhesive layer 30 contains 90% by mass or more of vinyl chloride resin relative to 100% by mass of the resin constituting the adhesive layer 30, and contains 80 to 110 parts by mass of plasticizer relative to 100 parts by mass of the vinyl chloride resin. On the other hand, the skin layer 10 contains 90% by mass or more of vinyl chloride resin relative to 100 parts by mass of the resin constituting the skin layer 10, and contains 65 to 80 parts by mass of plasticizer relative to 100 parts by mass of the vinyl chloride resin. In this way, in synthetic leather 100 containing vinyl chloride resin as the main resin, by adjusting the proportion of plasticizer in the adhesive layer 30 to be higher than the proportion of plasticizer in the skin layer 10, the flex resistance and abrasion resistance are improved, and bleeding of the plasticizer from the surface of the skin layer 10 over time can be suppressed.

[0044] The thickness t2 of the skin layer 10 is not particularly limited, but is preferably 150 μm or more from the viewpoint of favorably improving flex resistance, and is more preferably 200 μm or more, even more preferably 250 μm or more, and particularly preferably 300 μm or more from the viewpoint of excellent abrasion resistance in addition to flex resistance. On the other hand, from the viewpoint of excellent texture and flexibility as synthetic leather, the thickness t2 of the skin layer 10 is preferably 500 μm or less, more preferably 450 μm or less, and even more preferably 400 μm or less. The thickness t2 of the epidermis layer 10 is obtained by measuring the thickness of the epidermis layer 10 at 10 randomly selected points on the cut surface of the synthetic leather 100 observed under a microscope and calculating the arithmetic average of the measured values.

[0045] In addition to the vinyl chloride resin and optional plasticizer, the skin layer 10 preferably further contains at least one of an antifoaming agent and a defoaming agent, and more preferably both. The defoaming agent can move air bubbles generated inside the skin layer 10 to the surface, while the antifoaming agent can break down air bubbles generated on the surface of the skin layer 10. Treating the air bubbles in the skin layer 10 in this way can improve the abrasion resistance of the synthetic leather 100.

[0046] In the present invention, the term "antifoaming agent" refers to an agent that has the effect of dissolving (absorbing) small bubbles in a liquid or causing bubbles to burst. Specific examples of antifoaming agents include lower aliphatic alcohol-based antifoaming agents, higher aliphatic alcohol-based antifoaming agents, lower fatty acid-based antifoaming agents, higher fatty acid-based antifoaming agents, lower aliphatic amide-based antifoaming agents, higher aliphatic amide-based antifoaming agents, lower fatty acid ester-based antifoaming agents, higher fatty acid ester-based antifoaming agents, and silicone-based antifoaming agents. The content of the antifoaming agent is preferably in the range of 0.05 parts by mass or more and 0.3 parts by mass or less relative to 100 parts by mass of the vinyl chloride resin contained in the surface layer 10 .

[0047] In the present invention, the defoaming agent refers to a substance that has the effect of moving gas (bubbles) generated inside the skin layer 10 to the interface. Specific examples of the defoaming agent include polyoxyalkylene derivatives, lauryl alcohol sulfate, and sodium lauryl alcohol sulfate (sodium lauryl sulfate). The content of the defoaming agent is preferably in the range of 0.1 part by mass to 1.0 part by mass relative to 100 parts by mass of the vinyl chloride resin contained in the surface layer 10 .

[0048] Other additives: In addition to the resin and plasticizer, additives may be added to the skin layer 10 as appropriate within the scope of the present invention. Examples of such additives include stabilizers, fillers, flame retardants, and pigments.

[0049] Surface protection layer: The synthetic leather 100 has a surface protection layer 70 provided on the surface of the skin layer 10 opposite to the fabric 20 side. The surface protective layer 70 is composed of an appropriately selected resin or the like. For example, the surface protective layer 70 is composed of a polyurethane resin and a crosslinking agent. The surface protective layer 70 is a layer that protects the surface of the skin layer 10 and can improve the abrasion resistance, etc., of the synthetic leather 100. A polyurethane resin refers to a resin that contains a urethane bond in its molecule, and more specifically, refers to a resin that has a urethane bond in the repeating unit of its main chain.

[0050] The polyurethane-based resin constituting the surface protective layer 70 is formed by reacting two polyol components and may be any polyurethane-based resin capable of forming a layer suitable for protecting the surface side of the synthetic leather 100. One example is a water-based polyurethane-based resin. A water-based polyurethane-based resin is a polyurethane-based resin that has hydrophilic groups and is soluble or emulsifiable in water. Examples of such water-based polyurethane resins include polyurethanes with hydrophilic groups (anionic hydrophilic groups, cationic hydrophilic groups, or nonionic hydrophilic groups) in the molecule, or polyurethanes with hydrophilic segments. Among water-based polyurethane resins, polycarbonate-based polyurethane resins are preferred from the standpoints of durability, abrasion resistance, and hydrolysis resistance. Polycarbonate-based polyurethanes can be obtained, for example, by polyaddition reaction of polycarbonate-based diol and polyisocyanate.

[0051] The crosslinking agent may 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 thereof include carbodiimide-based crosslinking agents, isocyanate-based crosslinking agents, and oxazoline-based crosslinking agents.

[0052] In the surface protective layer 70 containing a polyurethane-based resin, the proportion of the crosslinking agent blended with respect to 100 parts by mass of the polyurethane-based resin contained in the surface protective layer 70 is not particularly limited, but is preferably, for example, 2 parts by mass or more and 20 parts by mass or less. If the crosslinking agent is less than 2 parts by mass, there is a risk that the abrasion resistance will be insufficient, and if it exceeds 20 parts by mass, there is a risk that the surface protective layer 30 will become hard and cracks will occur in the surface protective layer when bent.

[0053] The thickness of the surface protection layer 70 is not particularly limited, but from the viewpoint of being able to sufficiently protect the skin layer 10, it is preferably 0.5 μm or more and 20 μm or less.

[0054] (synthetic leather) As described above, the synthetic leather 100 contains a vinyl chloride resin in all of the skin layer 10, the foam layer 40, and the adhesive layer 30, and a plasticizer is contained in at least the adhesive layer 30. The skin layer 10 and the foam layer 40 also contain a plasticizer. In such synthetic leather 100, the amount of plasticizer contained in the entire synthetic leather 100 is preferably in the range of 70 parts by mass to 100 parts by mass per 100 parts by mass of vinyl chloride resin contained in the entire synthetic leather 100. In a more preferred embodiment, skin layer 10, foam layer 40, and adhesive layer 30 each contain 90% by mass or more of vinyl chloride resin out of 100% by mass or more of the resin constituting each layer, and skin layer 10, foam layer 40, and adhesive layer 30 each contain a plasticizer. In this embodiment, it is more preferred that adhesive layer 30 is the layer containing the greatest amount of vinyl chloride resin per 100 parts by mass of vinyl chloride resin contained in each layer.

[0055] As described above, by including a sufficient amount of plasticizer throughout the synthetic leather 100, which is composed of a large amount of vinyl chloride resin, it is easy to sufficiently improve the flex resistance and abrasion resistance of the synthetic leather 100 in a balanced manner.

[0056] The synthetic leather of the present invention described above is not particularly limited in its applications, but from the viewpoint of its excellent flex resistance, it is suitable as a sheet-like material for forming the seat side portion 213 of the vehicle seat 200. By using the synthetic leather of the present invention in the seat side portion 213, which is likely to be subjected to load when exiting the vehicle, it is possible to effectively prevent cracks in the seat side portion 213. Of course, the synthetic leather of the present invention can also be used in any or all of the parts of the vehicle seat 200 other than the seat side portion 213.

[0057] (Manufacturing method of synthetic leather) An example of a method for manufacturing synthetic leather 100 is described below. However, the manufacturing method described below does not limit the synthetic leather of the present invention, and the synthetic leather of the present invention may be manufactured by other manufacturing methods as appropriate within the scope of the present invention. The following describes an example of a synthetic leather having a surface layer 10, a foam layer 40, an adhesive layer 30, and a fabric 20. First, a coating solution for forming the surface layer containing a vinyl chloride resin and a plasticizer is prepared, and this is applied to release paper using a doctor knife coater, a comma doctor coater, or other conventional coating means, and then appropriately heated and cured to obtain the surface layer 10. Thereafter, a coating liquid for forming a foamed layer containing a foaming agent, a vinyl chloride resin, and a plasticizer is applied to the exposed surface of the obtained skin layer 10 using the same coating means as described above, and is appropriately heated to foam, thereby forming a foamed layer 40. Then, a coating solution for forming an adhesive layer (adhesive resin composition) containing a vinyl chloride resin and a plasticizer is applied to the exposed surface of the resulting foam layer 40 using the coating means described above, and the fabric 20 is laminated on top of it. In this state, the laminate is passed between opposing rolls spaced a predetermined distance apart to compress the laminate in the thickness direction, and then appropriately heated and cured to obtain a laminate. The amount of penetration of the adhesive resin composition into the fabric 20 can be adjusted by adjusting the distance between the rolls. The release paper or the like is then peeled off to obtain the synthetic leather 100. Thereafter, the surface of the skin layer 10 may be embossed, as appropriate, to impart a grained or ruffled pattern to create a leather-like appearance.

[0058] When a surface protective layer is further provided on the surface of the surface layer 10, the surface protective layer can be formed by applying a surface protective layer-forming coating liquid containing a polyurethane resin-forming composition and a crosslinking agent such as isocyanate to the surface of the surface layer 10 of the synthetic leather 100 obtained as described above, and then appropriately heating the coating liquid. Before forming the surface protective layer, the surface of the surface layer 10 may be subjected to the above-mentioned embossing process or the like. [Example]

[0059] Examples of the present invention will be described below. Examples and comparative examples are shown below using synthetic leather having a fabric, adhesive layer, foam layer, surface layer, and surface protection layer as an example. In the examples and comparative examples shown below, the resin constituting the surface layer, adhesive layer, and foam layer is 100% by mass of vinyl chloride resin. However, the examples shown below do not limit the present invention in any way.

[0060] First, the materials for each layer were prepared as follows. Tables 1 and 2 show the compositions and blending ratios of the coating solutions for the surface layer, foam layer, and adhesive layer. Tables 1 and 2 also show the dry thicknesses of the surface protection layer.

[0061] <Coating liquid for forming the surface layer> Vinyl chloride resin (degree of polymerization: 1800) Plasticizer (phthalate ester plasticizer, product name: PL-200, manufactured by C.G. Ester Co., Ltd.) Antifoaming agent (silicone compound, product name: BYK067A, manufactured by BYK) Defoaming agent (polyoxyalkylene derivative, product name: BYK3155, manufactured by BYK) <Coating liquid for forming foam layer> Vinyl chloride resin 1 (degree of polymerization: 1000) Vinyl chloride resin 2 (degree of polymerization: 1800) Plasticizer (phthalate ester plasticizer, product name: PL-200, manufactured by C.G. Ester Co., Ltd.) Foaming agent (azodicarbonamide) <Coating liquid for forming adhesive layer> Vinyl chloride resin (degree of polymerization: 1000) Plasticizer (phthalate ester plasticizer, product name: PL-200, manufactured by C.G. Ester Co., Ltd.) <Fabric> Polyester knit

[0062] Example 1 The coating solution for forming the surface layer, prepared according to the composition ratio shown in Table 1, was applied to release paper (manufactured by Dai Nippon Printing Co., Ltd., product name "DE-73") so that the thickness after curing would be as shown in Table 1, and the coating was cured in an oven at 180°C for 1 minute to obtain a surface layer. Next, a foam layer-forming coating liquid prepared with the composition ratio shown in Table 1 was applied to the exposed side of the obtained skin layer so that the thickness after curing and foaming would be as shown in Table 1, and the coating was cured in an oven at 200°C for 1 minute to obtain a foam layer. Furthermore, the adhesive layer-forming coating liquid prepared with the composition ratio shown in Table 1 was applied to the foam layer at the coating thickness shown in Table 1, and the fabric was laminated. The laminate was then passed through rolls with a gap (clearance) set to 80% of the total thickness of the release paper / surface layer / foam layer / adhesive layer / fabric, and then cured at 200°C for 1 minute. The release paper was then peeled off to obtain a laminate. Then, a coating liquid for forming a surface protective layer containing a water-based polyurethane resin composition and a crosslinking agent was applied to the exposed surface of the surface layer of the laminate in an amount of 20 g / m 2 The mixture was dried in an oven at 150°C for 2 minutes to form a surface protective layer, thereby obtaining the synthetic leather of Example 1.

[0063] Example 2 Synthetic leather was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the surface layer after curing was 200 μm.

[0064] Example 3 Synthetic leather was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the surface layer after curing was 400 μm.

[0065] Example 4 Synthetic leather was obtained in the same manner as in Example 1, except that a fabric with a thickness of 500 μm was used.

[0066] Example 5 Synthetic leather was obtained in the same manner as in Example 1, except that the amount of plasticizer added to the surface layer and the amount of plasticizer added to the foam layer were changed.

[0067] Example 6 Synthetic leather was obtained in the same manner as in Example 1, except that the type of vinyl chloride resin constituting the foam layer was changed.

[0068] Example 7 Synthetic leather was obtained in the same manner as in Example 1, except that a fabric with a thickness of 200 μm was used.

[0069] Example 8 A synthetic leather was obtained in the same manner as in Example 1, except that no foam layer was provided.

[0070] Example 9 Synthetic leather was obtained in the same manner as in Example 1, except that the coating was applied so that the thickness of the surface layer after curing would be 400 μm, no foam layer was provided, the adhesive layer-forming coating liquid was applied to the surface layer to a coating thickness of 200 μm, and a fabric with a thickness of 500 μm was used.

[0071] (Examples 10 and 11) Synthetic leather was obtained in the same manner as in Example 1, except that the amount of plasticizer added to the adhesive layer was changed.

[0072] Example 12 Synthetic leather was obtained in the same manner as in Example 1, except that no antifoaming agent was used in the skin layer.

[0073] Example 13 Synthetic leather was obtained in the same manner as in Example 1, except that no defoaming agent was used in the skin layer.

[0074] (Comparative Example 1) A synthetic leather was obtained in the same manner as in Example 1, except that the gap (clearance) between the rolls after laminating the fabric was set to 100% of the total thickness of the release paper / surface layer / foam layer / adhesive layer / fabric (i.e., the same as the total thickness).

[0075] (Comparative Example 2) Synthetic leather was obtained in the same manner as in Example 1, except that the gap (clearance) between the rolls after laminating the fabric was set to 60% of the total thickness of the release paper / surface layer / foam layer / adhesive layer / fabric.

[0076] (Comparative Example 3) Synthetic leather was obtained in the same manner as in Example 1, except that the amount of plasticizer added to the adhesive layer was changed.

[0077] The resulting synthetic leather was cut in the thickness direction, and the cut surface was observed under a microscope. The maximum dimension of the penetration area was measured at 10 locations on the cut surface, and the penetration thickness of the adhesive resin composition was determined by arithmetic average. The penetration thicknesses are shown in Tables 1 and 2.

[0078] [evaluation] The synthetic leathers obtained in the examples and comparative examples were evaluated as follows. A rating of ◯ (good) or Δ (fair) was considered to be suitable for practical use.

[0079] <Peel strength> According to JIS K6772-1994, the peel strength was measured when the interface between the synthetic leather fabric and the adhesive layer was peeled parallel to the surface using a tensile tester, and the peel strength was evaluated according to the following criteria. ○ (Good) 7N / cm or more △ (Acceptable) 4N / cm or more and less than 7N / cm × (Not acceptable) Less than 4N / cm

[0080] <Wear resistance> The test was conducted using a Gakushin type friction tester in accordance with JIS L0823-1971. The resulting synthetic leather was cut into test pieces 20 mm wide and 50 mm long, and the test pieces were attached to a friction element with the surface layer facing outward. Then, a test was conducted in which the friction element was rubbed against a No. 6 cotton canvas (30 mm wide, 250 mm long) fixed to a test table so as not to wrinkle, under the conditions of a pressure load of 1,000 fg, a stroke length of 100 mm, and a stroke speed of 30 strokes / min. The surface condition of the test piece after 10,000 strokes was visually observed and evaluated based on the following criteria. ○ (Good): No cracks were found on the surface layer. △ (Acceptable) - Slight damage to the surface layer was observed × (Unacceptable): The surface layer was severely damaged.

[0081] <Bending resistance> A flexography test was conducted at -20°C in accordance with JIS K6545-1994, and the condition of the synthetic leather was checked every 5,000 flexes. The number of flexes until cracks were observed in the synthetic leather was measured and evaluated according to the following criteria. ○(Good) 30,000 times or more △ (Acceptable) 15,000 times or more but less than 30,000 times × (Not acceptable) Less than 15,000 times

[0082] <Tactile sensation> Five testers held the synthetic leather in their hands, checked its feel, and judged whether it felt soft or not, and evaluated it according to the following criteria. ○ (Good): Four or five testers rated it as soft. △ (Acceptable): Two or three testers evaluated the product as soft. × (Fail): 0 or 1 tester rated it as soft

[0083] [Table 1]

[0084] [Table 2]

[0085] The above embodiment encompasses the following technical ideas. (1) A synthetic leather comprising a surface layer, a fabric, and an adhesive layer provided between the surface layer and the fabric, the surface layer and the adhesive layer contain a vinyl chloride resin, the adhesive layer contains a plasticizer in a range 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, A synthetic leather characterized in that the adhesive resin composition constituting the adhesive layer penetrates into the fabric to a depth of 100 μm or more and 300 μm or less. (2) The synthetic leather according to (1) above, wherein the synthetic leather contains a plasticizer in an amount of 70 to 100 parts by mass per 100 parts by mass of vinyl chloride resin contained in the entire synthetic leather. (3) The synthetic leather according to (1) or (2) above, wherein the surface layer contains a plasticizer in an amount of 65 to 90 parts by mass per 100 parts by mass of the vinyl chloride resin contained in the surface layer. (4) A foam layer is provided between the skin layer and the adhesive layer, The synthetic leather according to any one of (1) to (3), wherein the foam layer contains a vinyl chloride resin, and the degree of polymerization of the vinyl chloride resin contained in the skin layer is higher than the degree of polymerization of the vinyl chloride resin contained in the foam layer. (5) The synthetic leather according to any one of (1) to (4) above, which is a sheet-like material for forming the side surface of a seat of a vehicle seat. [Explanation of symbols]

[0086] 10...epidermal layer 12...Top surface 14...Bottom surface 20...Fabric 21. Warp 22. Weft 30...adhesive layer 32...Top surface 34...bottom surface 40...Foam layer 50... Penetration area 52. Fiber 60...space 70...Surface protective layer t1: Penetration thickness t2: Skin thickness t3: Thickness of the foam layer 100, 120, 140...Synthetic leather 200 Vehicle seats 210... Seat part 211 Backrest 212...Head 213...Seat side part 214 Backrest and side sections 215···Head side

Claims

1. A synthetic leather comprising a surface layer, a fabric, and an adhesive layer provided between the surface layer and the fabric, the surface layer and the adhesive layer contain a vinyl chloride resin, the adhesive layer contains a plasticizer in a range 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, A synthetic leather characterized in that the adhesive resin composition constituting the adhesive layer penetrates into the fabric to a depth of 100 μm or more and 300 μm or less.

2. 2. The synthetic leather according to claim 1, wherein the synthetic leather contains 70 to 100 parts by mass of a plasticizer relative to 100 parts by mass of a vinyl chloride resin contained in the entire synthetic leather.

3. 3. The synthetic leather according to claim 1, wherein the surface layer contains 65 to 90 parts by mass of a plasticizer relative to 100 parts by mass of the vinyl chloride resin contained in the surface layer.

4. a foam layer is provided between the skin layer and the adhesive layer; the foam layer contains a vinyl chloride resin, 4. The synthetic leather according to claim 1, wherein the degree of polymerization of the vinyl chloride resin contained in the surface layer is higher than the degree of polymerization of the vinyl chloride resin contained in the foam layer.

5. 5. The synthetic leather according to claim 1, which is a sheet-like material for forming a side surface of a seat of a vehicle seat.

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