Surface material, and backpack bag using the surface material

Abstract

The present invention provides a surface material that is resistant to wrinkles, or that easily returns to its original state even if wrinkles do occur, and that maintains a high-quality appearance, as well as a backpack made using this surface material. [Solution] A surface material in which the bending hysteresis 2HB (gf·cm / cm) and thickness h (mm) when bent in the outward direction satisfy the following formulas (I) and (II). 2HB ≤ 15h - 10 (I) 1.0 ≤ h ≤ 2.5 (II)

Description

[Technical Field]

[0001] This invention relates to a surface material and a backpack made using the surface material. [Background technology]

[0002] Bags of various types and shapes, such as school bags, backpacks, rucksacks, knapsacks, daypacks, school bags, one-shoulder bags, waist bags, and hip bags, have been known for a long time, depending on their intended use. Various proposals have been made regarding the components and surface materials that make up such bags.

[0003] For example, Patent Document 1 describes a shoulder strap comprising a mesh structure in which random loop-shaped continuous linear bodies made of thermoplastic resin are fused at the intersections of the continuous linear bodies, and a synthetic leather sheet in which a resin layer made of synthetic resin is formed on a base layer of nonwoven fabric or woven / knitted fabric, wherein the synthetic leather sheet preferably has a stiffness / softness of 0.1 mN or more and 1 mN or less as measured based on the Gurley bending rebound test, and is positioned on the side of the user's body of the luggage carrier. Patent Document 1 also describes that by using a synthetic leather sheet that is suitable for the body side rather than the surface side, having characteristics such as low stiffness / softness, the shoulder strap can sufficiently distribute the load applied to the body even if it is narrow in width. Patent Document 2 describes a shoulder strap material that uses at least a portion of a sheet (A) having substantially continuous convex portions and adjacent recesses on its surface, wherein the height difference between the convex portions and recesses, the vertical projected area of ​​the adjacent recesses, the average distance between the recesses, and the 20% compressive stress in the thickness direction are within a specific range. Patent Document 2 describes that the shoulder strap material has good cushioning, fit, and wearing comfort when the sheet (A) is used in the portion that comes into contact with the shoulder. Patent Document 3 describes an artificial leather in which a surface layer (1) made of polyurethane resin, an intermediate layer (A) which is a fibrous layer made by impregnating and solidifying porous polyurethane resin into a nylon ultrafine fiber nonwoven fabric, and a back layer (B) which is a fibrous layer made by impregnating and solidifying porous polyurethane resin into a polyester ultrafine fiber nonwoven fabric, are laminated, and the thickness ratio (A) / (B) of the intermediate layer to the back layer is 0.5 to 5. Patent Document 3 describes that this artificial leather sheet is particularly suitable as a material for school bags, and that school bag products using this artificial leather sheet for the main body crown, front section, shoulder straps, and gusset are full of luxury, have fine creases in the crown, and have excellent cushioning. Patent Document 4 describes a flap material for a flap-type bag, in which a colored layer is formed on the back surface of a fiber base layer, and a polyurethane surface layer containing a binder polyurethane and polyurethane fine particles is laminated on the side opposite to the back surface. Patent Document 4 also describes that this flap material for a flap-type bag has a smooth surface, gloss, vivid color, good creasing and texture, and excellent flexibility. Patent Document 5 describes a school bag characterized by having a linear reinforcing material (10) made of a shape-memory material attached to the left and right sides (7a)(7a) of a flap (7) to which a fastener (6) is attached at the lower end. Patent Document 5 describes that, due to the function of the shape-memory material, when the fastener (6) is released, the flap (7) of the school bag will naturally stand up, making it easy to open the flap (7). Furthermore, even if the flap (7) deforms due to a load exceeding the elastic limit of the reinforcing material (10), it can be easily returned to its original shape, so the appearance is not spoiled. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-58438 [Patent Document 2] Japanese Patent Publication No. 2007-412 [Patent Document 3] Japanese Patent Publication No. 2000-239974 [Patent Document 4] Japanese Patent Publication No. 2010-194242 [Patent Document 5] Registered Utility Model No. 3011706 Gazette [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, bags have become not only expected to be durable, but also to possess a sense of luxury. In the shoulder straps and flaps of backpacks and other bags, using thicker outer material makes it more difficult to bend at sharp angles, thus reducing wrinkles and giving the surface a firmer, more luxurious feel. However, when the outer material is thick, deep indentations can form on the inner surface when bent, leading to buckling. Furthermore, the distortion caused by this buckling can easily create large wrinkles that detract from the surface's firmness. Additionally, the internal distortion makes it difficult for wrinkles to return to their original state, and the resulting wrinkles diminish the luxurious feel of the outer material. On the other hand, making the outer material thinner improves its ability to follow bending and makes buckling less likely. However, if the outer material is thin, the cushioning against contact pressure of objects decreases, the surface becomes more prone to wear and peeling, and especially when used for shoulder straps or flaps, the shape of the core material combined on the back side becomes more easily visible on the surface, leading to a premature decline in durability and a sense of luxury.

[0006] Furthermore, with backpacks such as school bags, the shoulder straps are often folded in the opposite direction to how they are normally used, that is, with the outer side facing inward, during packaging before shipment from the manufacturer. Folding the shoulder straps in this way can cause wrinkles, which can reduce the perceived quality of the product when it is sold. Furthermore, during normal use by the user, the flap is repeatedly opened and closed, causing the surface to fold inward. Such prolonged and repeated folding can cause wrinkles to form on the surface of the shoulder straps and flap that are difficult to return to their original state, making it difficult to maintain a high-quality appearance during use.

[0007] The object of the present invention is to provide a skin material that is less likely to develop wrinkles on its surface, or that easily returns to its original state even if wrinkles do occur on the surface, and that maintains a high-class feeling, and a backpack using such a skin material.

Means for Solving the Problems

[0008] As a result of various studies, the inventors of the present invention have found that the bending hysteresis 2HB and the thickness h when the surface is bent inward satisfy a specific relationship, and thus the above problems can be solved, leading to the present invention. That is, the present invention includes the following inventions.

[0009] [1] A skin material in which the bending hysteresis 2HB (gf·cm / cm) when bent in the surface direction and the thickness h (mm) satisfy the following formulas (I) and (II). 2HB ≦ 15h - 10 (I) 1.0 ≦ h ≦ 2.5 (II) [2] The skin material according to [1] above, which is used for one or more selected from shoulder straps and covers. [3] The skin material according to [1] or [2] above, which has an embossed surface and the maximum height difference between the convex and concave portions of the embossed surface is 120 μm or less. [4] The skin material according to [1] or [2] above, in which the arithmetic mean roughness is 10 μm or less. [5] The skin material according to [1] or [2] above, which is disposed on the outer surface side. [6] The skin material according to [1] or [2] above, which is for use in a schoolbag. [7] A backpack using the skin material according to [1] or [2] above.

Effects of the Invention

[0010] According to the present invention, it is possible to provide a skin material that is less likely to develop wrinkles on its surface, or that easily returns to its original state even if wrinkles do occur on the surface, and that maintains a high-class feeling, and a backpack using such a skin material.

Modes for Carrying Out the Invention

[0011] The following describes the surface material according to an embodiment of the present invention, and a backpack using the surface material according to an embodiment of the present invention (hereinafter sometimes referred to as "the surface material of this embodiment" and "the backpack using the surface material of this embodiment"). In this specification, preferred forms of embodiments are shown, but combinations of two or more individual preferred forms are also preferred forms. If there are several numerical ranges for a given item, a preferred form can be created by selectively combining the lower and upper limits of those ranges. In this specification, when a numerical range such as "XX~YY" is mentioned, it means "XX or greater and YY or less." In this specification, when the surface material is stretched, the direction in which the stretchability is least pronounced is called the "longitudinal direction" of the surface material, and the direction perpendicular to that direction is called the "transverse direction" of the surface material. In this specification, "cover" refers to a "cover lid" or "flap," and is a lid-like part that covers the entire opening of a bag. In this specification, "number-average molecular weight" refers to the molecular weight on a standard polystyrene basis, determined by gel permeation chromatography (GPC) measurement.

[0012] [Skin material] The surface material of this embodiment satisfies the following formulas (I) and (II) for both its bending hysteresis 2HB (unit: gf·cm / cm, sometimes simply referred to as 2HB) and thickness h (unit: mm) when bent in the outward direction. It is also preferable that the bending hysteresis 2HB when bent in the direction opposite to the outward direction similarly satisfies the following formulas (I) and (II). 2HB ≤ 15h - 10 (I) 1.0 ≤ h ≤ 2.5 (II) In this specification, "thickness" refers to the value measured at a pressure of 23.5 kPa in accordance with JIS L1096:2020. Furthermore, in equations (I) and (II) above, the values ​​obtained by removing the units from the values ​​of bending hysteresis 2HB and thickness h are applied.

[0013] In this specification, when a part containing a surface material is formed of multiple layers, and an inner layer has a hardness difference of more than 30 from the outermost layer, the outermost layer is considered the surface material. In this case, the bending hysteresis 2HB when bent in the outward direction is measured using only the outermost layer (with the inner layers removed), and the thickness of the surface material refers to the thickness of the outermost layer. In this specification, "hardness difference" refers to the difference in hardness, which is the median of five values ​​measured using a Type C durometer as specified in "7. Hardness Test" of JIS K7312:1996. Hardness measurement is performed on a smooth and sufficiently hard surface (a Type D durometer measurement value of 80 or higher as specified in "7. Hardness Test" of JIS K7312:1996), with the surface facing outwards when the part is constructed being used as the measurement surface. If the thickness of the object to be measured is less than 10 mm, multiple objects should be stacked with their measurement surfaces aligned in the same direction so that the total thickness is 10 mm or more. In this specification, a part containing a surface material is formed of multiple layers, with an inner layer having a hardness difference of 30 or less from the outermost layer, and the outermost layer can be peeled off from the inner layer with a peel strength of 35 N / 25 mm or less. In this case, the outermost layer is the surface material. In this case, the bending hysteresis 2HB when bent in the outward direction is measured using only the outermost layer (with the inner layers peeled off), and the thickness of the surface material refers to the thickness of the outermost layer. In this specification, a part containing a surface material is formed of multiple layers, with an inner layer having a hardness difference of 30 or less from the outermost layer, and the outermost layer cannot be peeled off the inner layer with a peel strength of 35 N / 25 mm or less. In this case, the outermost layer and the inner layer together constitute the surface material. In this case, the bending hysteresis 2HB when bent in the outward direction is measured using the surface material including the outermost and inner layers (without peeling off the inner layer), and the thickness of the surface material refers to the surface material including the outermost and inner layers. If the outermost layer cannot be peeled from the inner layer with a peel strength of 35 N / 25 mm or less, interlayer slippage is less likely to occur at the interface between the outermost and inner layers, and the material bends integrally during repeated bending. Therefore, even when the surface of the skin material is repeatedly folded in the direction where the surface side faces inward, wrinkles are less likely to form on the surface. Furthermore, the bending resilience of the skin material is not impaired, and there is no adverse effect on maintaining the performance of the part using the skin material. The above-mentioned inner layer may be a single layer or a multi-layer layer.

[0014] The surface material satisfying the above formulas (I) and (II) not only suppresses buckling and is resistant to wrinkles, or if wrinkles do occur, they easily return to their original state, but also maintains a high-quality appearance. The surface material of this embodiment is not particularly limited as long as it satisfies the above formulas (I) and (II). However, from the viewpoint of obtaining a surface material that is less prone to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance, it is preferable to include a fibrous base material such as a woven or knitted fabric or a nonwoven fabric, and it is more preferable to include a fibrous base material that is a nonwoven fabric. Furthermore, from the same viewpoint, it is preferable that the surface material of this embodiment has a coating layer on its surface.

[0015] Hysteresis 2HB can be adjusted, for example, by changing the type, modulus, and content of the resin constituting the fibers and polymer elastic material in the fibrous base material contained in the surface material, as well as the ratio of fibers to polymer elastic material. For example, by using ultrafine fibers or hollow fibers as the fibers, the bending stress of the fibers is reduced, thereby reducing hysteresis 2HB. Alternatively, by increasing the ratio of polymer elastic material, the resilience of the surface material is increased, which also reduces hysteresis 2HB.

[0016] In this embodiment, the 2HB (gf·cm / cm) of the surface material is preferably 4.0 gf·cm / cm or higher, more preferably 4.5 gf·cm / cm or higher, and even more preferably 5.0 gf·cm / cm or higher, from the viewpoint of suppressing the occurrence of wrinkles, and from the viewpoint of restoring the wrinkles to their original state and maintaining a high-quality appearance even if wrinkles occur, it is preferably 18.0 gf·cm / cm or lower, more preferably 16.0 gf·cm / cm or lower, and even more preferably 14.0 gf·cm / cm or lower.

[0017] In this embodiment, the thickness h (mm) of the surface material is preferably 1.1 mm or more, more preferably 1.2 mm or more, and even more preferably 1.3 mm or more, from the viewpoint of providing a sense of luxury, and preferably 2.3 mm or less, more preferably 2.1 mm or less, and even more preferably 2.0 mm or less, from the viewpoint of suppressing the occurrence of wrinkles.

[0018] From the viewpoint of weight reduction, the apparent density of the surface material in this embodiment is preferably 0.50 g / cm³. 3 More precisely, 0.40 g / cm³ 3 More preferably, 0.35 g / cm³ 3 The following is preferred, and from the viewpoint of tensile strength, tear strength, seam strength, and shape retention, it is preferably 0.25 g / cm 3 More preferably 0.30 g / cm³ 3 More preferably 0.32 g / cm³ 3 That's all. The apparent density was determined by taking two 10cm x 10cm test pieces and measuring the mass of each piece using an electronic balance. 2 This value is calculated by converting it to a mass per unit area, and then taking the average value and the thickness of the test specimen.

[0019] The surface material of this embodiment may be embossed. That is, the surface material of this embodiment may have an embossed surface with recesses and protrusions. If the surface material of this embodiment has an embossed surface, the maximum height difference between the convex and concave parts on the surface of the surface material is preferably small from the viewpoint of giving a sense of luxury, but it may be 120 μm or less, 60 μm or less, 20 μm or less, and from the viewpoint of ease of manufacturing, it may be 5 μm or more, 10 μm or more, or 15 μm or more. In this invention, the "maximum height difference between convex and concave portions" on the surface of the surface material is the average value of the maximum height (Rz) obtained by measuring three randomly selected locations on the surface of the surface material at a magnification of 40x using a KEYENCE VR-3000 3D surface shape measuring machine, and filtering the obtained measurements with no low-pass filter (S-filter) and a high-pass filter (L-filter) of 1 mm.

[0020] The arithmetic mean roughness (Sa) on the surface of the skin material is preferably small from the viewpoint of giving a sense of luxury, but it may be 10 μm or less, 7 μm or less, 3 μm or less, and from the viewpoint of ease of manufacture, it may be 0.5 μm or more, 1 μm or more, or 2 μm or more. In this invention, "arithmetic mean roughness (Sa)" refers to the average value of the arithmetic mean roughness (Sa) obtained by measuring three randomly selected locations on the surface of the surface material at a magnification of 40x using a KEYENCE VR-3000 3D surface shape measuring machine, and then filtering the obtained measurements with no low-pass filter (S-filter) and a high-pass filter (L-filter) of 1 mm.

[0021] The surface material of this embodiment preferably has the flexural hardness of a sheet material that covers the outer surface, and preferably the gaul bending resilience of the surface and back surface is 2.5 to 25 mN, and more preferably either the surface or the back surface is 10 mN or more. By providing the necessary bending hardness for a sheet material covering the outer surface, it is possible to create a surface material that is less prone to wrinkles, or that recovers more easily from wrinkles that do occur, resulting in a more lasting sense of luxury. In this specification, "Gare bending resilience" refers to a value measured in accordance with JIS L1096:2020, 8.22 Bending resilience, Method A.

[0022] <Textile base material> As the fibers constituting the knitted or nonwoven fabrics that serve as the fiber base material, any of the conventionally known natural fibers, synthetic fibers, or semi-synthetic fibers can be used, as long as they provide a surface material that satisfies the above formulas (I) and (II). Industrially, known cellulose fibers, acrylic fibers, polyester fibers, polyamide fibers, and polyolefin fibers, either individually or in mixtures, are preferred in terms of quality stability and cost. Among these, polyester fibers, polyamide fibers, and polyolefin fibers are preferred, with polyamide fibers being more preferred. Furthermore, recycled resins and bio-resins can also be used as raw materials for the fibers.

[0023] Examples of polyamide resins that constitute polyamide fibers include polyamide 6, polyamide 6,6, polyamide 6,10, polyamide 10,10, polyamide 11, and polyamide 12. Among these, polyamide 6 and polyamide 6,6 are preferred from the viewpoint of availability, and polyamide 6 is more preferred. The above polyamide resin may be used individually or in combination of two or more types.

[0024] The polyamide resin may contain various additives, to the extent that they do not impair the effects of the present invention. Examples of additives include catalysts, colorants, heat-resistant agents, flame retardants, lubricants, antifouling agents, fluorescent whitening agents, matting agents, gloss improvers, antistatic agents, fragrances, deodorizers, antibacterial agents, mite repellents, and inorganic fine particles.

[0025] From the viewpoint of obtaining a surface material that is less prone to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance, the fiber length of the fibers contained in the fibrous base material is preferably 30 mm or more, more preferably 35 mm or more, even more preferably 40 mm or more, preferably 70 mm or less, more preferably 65 mm or less, and even more preferably 60 mm or less.

[0026] From the viewpoint of obtaining a surface material that is resistant to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance, the fibers constituting the fibrous base material are preferably ultrafine fibers or porous hollow fibers, and more preferably ultrafine fibers. In this specification, "ultrafine fiber" refers to a fiber that has been made ultrafine by removing at least one component from a multi-component fiber (composite fiber) consisting of at least two or more spun polymers having different chemical or physical properties. In the present invention, although not particularly limited, ultrafine fibers that can achieve a flexible texture closer to that of natural leather are preferred, and ultrafine fibers or bundles of ultrafine fibers having an average fineness of 0.3 dtex or less, particularly 0.1 dtex or less, and an average fineness of 0.0001 dtex or more, particularly 0.001 dtex or more, are preferably used.

[0027] The surface material of this embodiment may contain two or more fiber base materials with different fiber types, fiber lengths, and average fineness, or it may contain one type alone.

[0028] When a part containing a surface material is formed as a single layer, the thickness of the fibrous base material contained in the surface material is preferably 1.0 mm or more, more preferably 1.1 mm or more, and even more preferably 1.2 mm or more, from the viewpoint of giving a sense of luxury, and preferably 2.5 mm or less, more preferably 2.3 mm or less, and even more preferably 2.1 mm or less, from the viewpoint of suppressing the occurrence of wrinkles.

[0029] In a part containing a surface material, where multiple layers are formed, and an inner layer is laminated with a hardness difference of 30 or less from the outermost layer, and the outermost layer cannot be peeled off the inner layer with a peel strength of 35 N / 25 mm or less, the total thickness of the fibrous base material contained in the outermost and inner layers is preferably 1.0 mm or more, more preferably 1.1 mm or more, and even more preferably 1.2 mm or more from the viewpoint of giving a sense of luxury, and preferably 2.5 mm or less, more preferably 2.3 mm or less, and even more preferably 2.1 mm or less from the viewpoint of suppressing the occurrence of wrinkles.

[0030] <Polymer elastic material> In this embodiment, the surface material preferably contains a polymeric elastic material from the viewpoint of providing a sense of luxury, a texture similar to natural leather, and shape stability. The surface material of this embodiment may contain a polymeric elastic material in its fibrous base material, or the coating layer formed on the surface of the surface material may contain a polymeric elastic material, or the fibrous base material of the surface material may contain a polymeric elastic material and the coating layer formed on the surface of the surface material may also contain a polymeric elastic material.

[0031] The polymeric elastic material contained in the fibrous base material of the surface material can be any known polymeric elastic material commonly used in the manufacture of artificial leather, such as polyurethane resins, polyester elastomers, rubber resins, polyvinyl chloride resins, polyacrylic acid resins, polyamino acid resins, silicone resins, and modified products, copolymers, or mixtures thereof. The polymeric elastic material may be contained in the fibrous base material alone or in combination of two or more types. From the viewpoint of giving the surface material a high-quality feel, it is preferable that the fibrous base material included in the surface material contains a polyurethane resin as a polymeric elastic material.

[0032] Examples of polyurethane resins include various polyurethanes obtained by reacting, in a predetermined molar ratio, at least one selected from polymer diols such as polyester diols, polyether diols, polyester ether diols, polylactone diols, and polycarbonate diols, having a number average molecular weight of 500 to 3000; at least one organic diisocyanate selected from aromatic, alicyclic, and aliphatic organic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; and at least one chain extender selected from low molecular weight compounds having at least two active hydrogen atoms, such as diols such as ethylene glycol, diamines, hydroxyamines, hydrazines, and hydrazides. Among these, polyurethane obtained by reacting at least one polymer diol selected from polyester diol, polyether diol, polycarbonate diol, etc. is preferred. Furthermore, the raw materials for polyurethane can also include diols made from bio-based materials, diols made from carbon dioxide, and diols obtained from chemical recycling.

[0033] The fibrous base material included in the surface material may contain one type of polyurethane as a polymeric elastic material, or two or more types of polyurethane, and may also contain synthetic rubber, polyester elastomer, polyvinyl chloride, etc.

[0034] The mass ratio of the fibrous base material contained in the surface material to the polymeric elastic material contained in the fibrous base material can be appropriately selected to adjust the physical properties and texture, and is not particularly limited. For example, when the surface material of the present invention is used as the shoulder strap of a school bag, the mass ratio of the fibrous base material to the polymeric elastic material (fibrous base material / polymeric elastic material) is preferably 80 / 20 to 20 / 80, more preferably 70 / 30 to 30 / 70, and even more preferably 60 / 40 to 40 / 60.

[0035] When the fibrous base material contains a polymeric elastic material, it is preferable that the polymeric elastic material exists in a sponge-like solidified state. Furthermore, it is preferable that the fibrous base material has a porous layer formed from the sponge-like solidified polymeric elastic material. Because the fibrous base material has a porous layer formed from a polymeric elastic material solidified into a sponge-like state, it is easy to obtain a texture similar to natural leather, and it is easy to obtain a surface material that is resistant to wrinkles, or if wrinkles do occur, they easily return to their original state, thus maintaining a high-quality appearance.

[0036] The thickness of the porous layer is preferably 100 to 800 μm, more preferably 200 to 600 μm, and even more preferably 300 to 500 μm, from the viewpoint of providing a texture similar to natural leather, and from the viewpoint of obtaining a surface material that is less prone to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance.

[0037] <Coating layer> The surface material of this embodiment preferably has a coating layer on its surface. Furthermore, if the surface material has multiple layers of fibrous base materials, it is preferable to have the coating layer on the outermost fibrous base material. Examples of polymeric elastic materials included in the coating layer formed on the surface of the surface material include synthetic rubber, polyester elastomer, polyvinyl chloride, and polyurethane resins. Among these, polyurethane resins are preferred from the viewpoint of elasticity, softness, abrasion resistance, and the ability to form a porous state. The polyurethane resin mentioned above can be a polyurethane similar to the polymer elastomer contained in the fibrous base material included in the surface material. Furthermore, a mixture of multiple types of polyurethane may be used as needed, and a polymer composition mainly composed of polyurethane resin obtained by adding polymers such as synthetic rubber, polyester elastomer, and polyvinyl chloride can also be used. Among these, polyurethane obtained by reacting at least one polymer diol selected from polyester diol, polyether diol, etc., is preferred.

[0038] The coating layer containing the polymeric elastic material may contain one type of polyurethane, two or more types of polyurethane, or synthetic rubber, polyester elastomer, polyvinyl chloride, etc.

[0039] The coating layer containing the polymeric elastic material may contain additives such as colorants, lightfasteners, dispersants, deodorants, antibacterial agents, and foaming agents. One additive may be used alone, or two or more may be used.

[0040] The coating layer containing the polymeric elastic material may be a single layer or a layer of two or more layers. If the coating layer containing the polymeric elastic material consists of two or more layers, each layer may contain the same polymeric elastic material, or it may contain different polymeric elastic materials.

[0041] The thickness of the coating layer containing the polymeric elastic material is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, from the viewpoint of obtaining a surface material that is less prone to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance. From the viewpoint of suppressing the occurrence of wrinkles, it is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 230 μm or less. Furthermore, the thickness of the coating layer containing the polymer elastic material refers to the total thickness if the coating layer consists of two or more layers.

[0042] The polymer elastomer content in the coating layer containing the polymer elastomer is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and may be 100% by mass.

[0043] When a coating layer containing a polymeric elastic material is formed on the surface of a surface material, the surface material may have an adhesive layer between the coating layer and the fibrous substrate for joining the coating layer and the fibrous substrate. From the viewpoint of adhesion and flexibility, polyurethane-based adhesives, acrylic-based adhesives, and melamine-based adhesives are preferred as the adhesives that constitute the adhesive layer, with polyurethane-based adhesives being more preferred. From the viewpoint of adhesion, the thickness of the adhesive layer is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. From the viewpoint of providing a sense of luxury, it is preferably 100 μm or less, more preferably 90 μm or less, and even more preferably 80 μm or less.

[0044] When forming a coating layer containing a polymeric elastic material on the surface of a surface material, the surface material may be formed by impregnating a fibrous base material with an adhesive and bonding the coating layer to the fibrous base material. In other words, the fibrous base material may contain an adhesive. Examples of adhesives used to impregnate the fibrous base material include those similar to the adhesive used to constitute the adhesive layer described above.

[0045] When a coating layer containing a polymeric elastic material is formed on the surface of a surface material, the polymeric elastic material may be in a sponge-like solidified state. Furthermore, the coating layer may have a porous layer formed from the sponge-like solidified polymeric elastic material. The coating layer has a porous layer formed from a polymeric elastic material solidified into a sponge-like state, making it easy to obtain a texture similar to natural leather.

[0046] <Other ingredients> The surface material of this embodiment may or may not contain components other than the fibrous base material and the polymer elastic body. Examples of such other components include those similar to the additives contained in the polyamide resin described above, and those contained in the coating layer containing the polymer elastic body. These other components may be encapsulated within at least one of the fibrous base material and the polymer elastic body. The content of the above-mentioned other components is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 2% by mass, in the surface material, in order to facilitate the expression of the desired effects of the above-mentioned other components and from the viewpoint of water absorption, water repellency, stain resistance, etc.

[0047] <Applications of surface materials> The surface material of this embodiment is resistant to wrinkles, or if wrinkles do occur, they easily return to their original state, and maintains a high-quality appearance. Therefore, it can be used not only for bags, but also for shoes, clothing, balls, furniture such as sofas, car seats, and various other applications. The outer material of this embodiment can be suitably used in backpacks such as school bags, rucksacks, knapsacks, daypacks, school bags, one-shoulder bags, waist bags, and hip bags. Among these backpacks, it can be particularly suitably used in school bags. When the outer material is used in a school bag, it is preferable to use it on the shoulder straps and flap, where wrinkles are likely to be perceived as a decrease in the sense of luxury, and it is even more preferable to place it on the outer surface side that does not directly come into contact with the body.

[0048] [Method for manufacturing surface material] From the viewpoint of obtaining a surface material that is resistant to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance, it is preferable to manufacture the surface material of this embodiment by a manufacturing method comprising the following steps (1A) to (4A) (first embodiment) or by a manufacturing method comprising the following steps (1B) to (4B) (second embodiment). Furthermore, the first and second embodiments may or may not further include the following step (5).

[0049] <First Embodiment> Process (1A): Process for preparing a fiber web formed from ultrafine fiber generation type fibers. Step (2): Step to obtain an entangled nonwoven fabric using the fiber web. Step (3): Step of impregnating the entangled nonwoven fabric with the polymeric elastic material. Process (4A): Process to remove marine components from the ultrafine generated fibers. Step (5): Step of forming a coating layer containing a polymer elastic material.

[0050] <Second Embodiment> Process (1B): Process for preparing a fiber web formed from hollow fiber-generating fibers. Step (2): Step to obtain an entangled nonwoven fabric using the fiber web. Step (3): Step of impregnating the entangled nonwoven fabric with the polymeric elastic material. Process (4B): Process to remove island components from the hollow fiber generating type fiber. Step (5): Step of forming a coating layer containing a polymer elastic material. The following describes each step.

[0051] <Process (1A)> Step (1A) is a step in which a fiber web formed from ultrafine fiber-generating fibers is prepared. As described above, ultrafine fibers are fibers that have been made ultrafine by removing at least one component from a multi-component fiber (composite fiber) consisting of at least two types of spun polymers with different chemical or physical properties. The multi-component fiber that generates these ultrafine fibers is called an ultrafine fiber generating fiber. Typical examples of ultrafine fiber generating fibers include sea-island type composite fibers, multilayer laminated composite fibers, and radial laminated composite fibers obtained using methods such as the chip blend (mixed spinning) method and the composite spinning method. Among these, sea-island type composite fibers are preferred from the viewpoint of increasing productivity through high-speed spinning and obtaining artificial leather with excellent surface abrasion resistance and pilling resistance. From a similar viewpoint, it is preferable to obtain a fiber web by melt spinning sea-island type composite fibers. In the case of ultrafine fiber generation type fibers that are sea-island type composite fibers, the island component is dispersed in the sea component which forms the matrix in the fiber cross-section, and by removing the sea component, ultrafine fibers in the form of fiber bundles are generated. The following describes in more detail a method for obtaining a fiber web by melt-spinning sea-island type composite fibers, using sea-island type composite fibers as the ultrafine fiber generating type fibers.

[0052] Examples of resins that make up the island components of sea-island composite fibers, which later become ultrafine fibers, include resins similar to the polyamide resins that constitute polyamide fibers. For sea-island composite fibers, it is preferable to use a resin that differs in solubility or decomposition properties from the island component resin and has low compatibility, as the resin for the sea component that is removed by extraction or decomposition. Such a resin is preferably selected appropriately depending on the type and manufacturing method of the island component resin. Examples of marine resins include olefin resins such as polyethylene, polypropylene, ethylene propylene copolymer, and ethylene vinyl acetate copolymer, as well as resins that are soluble in organic solvents and can be dissolved and removed by organic solvents, such as polystyrene, styrene acrylic copolymer, and styrene ethylene copolymer. Additionally, resins that can be removed using only water without solvents, such as polyvinyl alcohol resins, water-soluble polyester resins, easily alkali-degradable modified polyester resins, polyacrylamide resins, and carboxymethylcellulose resins, are also included. Among these, polyethylene and polystyrene are preferred from the viewpoint of melt spinning properties.

[0053] The mass ratio of sea components to island components in sea-island composite fibers is not particularly limited, but for example, a range of sea component:island component = 5:95 to 80:20 is preferable. If the sea component polymer ratio in sea-island composite fibers is 5% by mass or more, the spinning stability of the sea-island fibers is less likely to decrease, making it easier to ensure industrial productivity. In addition, when a polymeric elastic material is added, after removing the sea components, voids of the required size are more easily formed between the ultrafine fiber bundle and the polymeric elastic material, resulting in a feeling of fullness, richness, and a dense surface. On the other hand, if the sea component polymer ratio is 60% by mass or less, the shape and distribution of island components in the cross-section of the sea-island fibers are stable, making it easier to prevent a decrease in quality stability.

[0054] Conventional methods known as the carding method, papermaking method, and spunbond method can be used to manufacture fiber webs. In this embodiment, it is preferable to melt-spin the fibers, then stretch the resulting fibers to about 1 to 5 times their original length, apply crimp, cut the fiber length to about 30 to 70 mm to obtain short fibers, then defibrate them with a card, and pass them through a webber to obtain a fiber web with the desired density.

[0055] <Process (1B)> Step (1B) is a step in which a fiber web formed from hollow fiber-generating fibers is prepared. Typical examples of hollow fiber-generating fibers include sea-island type composite fibers, multilayer laminated composite fibers, and radial laminated composite fibers obtained using methods such as chip blending (mixed spinning) or composite spinning. Among these, sea-island type composite fibers are preferred. In the case of a hollow fiber-generating fiber that is a sea-island type composite fiber, the island component is dispersed in the sea component which forms the matrix in the fiber cross-section. When the island component is removed, the sea component remains, resulting in a porous hollow fiber with many hollow sections within the fiber.

[0056] Examples of marine resins included in sea-island composite fibers that later become porous hollow fibers include resins similar to the polyamide resins that make up polyamide fibers. Examples of island component resins contained in sea-island composite fibers that are removed by extraction or decomposition include those similar to the sea component resin in process (1A), and the preferred embodiments are also the same.

[0057] The mass ratio of sea component to island component in sea-island type composite fibers is not particularly limited, but from the viewpoint of cross-sectional formation, 10 / 90 to 60 / 40 is preferred, and 20 / 80 to 60 / 40 is more preferred.

[0058] Conventional methods known as the carding method, papermaking method, and spunbond method can be used to manufacture fiber webs. In this embodiment, it is preferable to melt-spin the fibers, then stretch the resulting fibers to about 1 to 5 times their original length, apply crimp, cut the fibers to a length of about 3 to 7 cm to obtain short fibers, then defibrate them with a card, and pass them through a webber to obtain a fiber web with the desired density.

[0059] <Process (2)> Step (2) is a step of obtaining an entangled nonwoven fabric using the fiber web. In step (2), the fiber web is layered in multiple layers using a cross wrapper or the like as needed to form a laminate of fiber webs, and then subjected to an entanglement process to obtain an entangled nonwoven fabric.

[0060] Examples of the complexing treatment method include needle punching or high-pressure water jet treatment under the condition that at least one barb penetrates simultaneously or alternately from both sides. When performing the complexing treatment by the needle punching method, various treatment conditions such as the type of needles (the shape, size, barb shape, depth, number, and position of the barbs), the punching density of the needles (the density of the number of needles planted per unit area of the needle board multiplied by the number of reciprocations of piercing the fiber web per unit area by the needle group, that is, the needle punching treatment density per unit area), and the punching depth of the needles (the depth of piercing the fiber web with the needle group) are appropriately selected and implemented. Also, as the punching density of the needle punching treatment, it is preferable that it is 300 to 4000 punches / cm 2 from the viewpoint that high wear resistance can be easily obtained due to the balance between the complexing state and the fiber density. If the punching density is 300 punches / cm 2 or more, the fibers bent in the thickness direction by the barbs approach each other, accelerating the complexing and increasing the fiber density to obtain a sufficient complexing state. Also, if the punching density is 4000 punches / cm 2 or less, the cutting of the fibers by the barbs, which is likely to occur due to the excessive increase in fiber density, is suppressed, and in particular, it is difficult for the complexing state to deteriorate on the surface layer of the fiber web.

[0061] Also, at any stage from the melt spinning of the sea-island composite fiber to the complexing treatment, an oil agent or an antistatic agent may be applied to the ultrafine fiber generating type fiber, hollow fiber generating type fiber, fiber web, fiber web laminate, complex nonwoven fabric, etc. Furthermore, if necessary, a shrinkage treatment of immersing the ultrafine fiber generating type fiber, hollow fiber generating type fiber, fiber web, fiber web laminate, complex nonwoven fabric, etc. in warm water at about 70 to 150°C may be performed to make the complexing state dense in advance.

[0062] The basis weight of the complex fiber sheet is 100 to 1000 g / m 2It is preferable that the range be such. Furthermore, the entangled fiber sheet may be subjected to a treatment that further increases the fiber density and degree of entanglement by heat shrinking as needed. In addition, a heat press treatment may be performed as needed to further densify the entangled fiber sheet that has been densified by the heat shrinking treatment, as well as to fix the shape of the entangled fiber sheet and smooth the surface.

[0063] Furthermore, the entangled nonwoven fabric may be subjected to buffing treatment in order to smooth its surface.

[0064] <Process (3)> Step (3) is the step of impregnating the entangled nonwoven fabric with the polymeric elastic material. Methods for impregnation include known methods such as the dip-nip method, knife-coat method, bar-coat method, roll-coat method, and spray-coat method, in which a solution or dispersion containing a polymeric elastic material is used to impregnate the entangled nonwoven fabric with the polymeric elastic material alone or in combination.

[0065] Details of the polymeric elastic material used in process (3) are as described in the "Polymeric Elastic Material" section above.

[0066] The content of the polymeric elastic material in the solution or dispersion containing the polymeric elastic material is preferably 10 to 60% by mass. Solutions or dispersions containing polymeric elastic materials may contain various additives as appropriate, to the extent that they do not impair the properties of the final surface material, such as colorants (dyes, pigments, etc.), coagulation regulators, antioxidants, ultraviolet absorbers, fluorescent agents, fungicides, penetrating agents, defoamers, lubricants, water repellents, oil repellents, thickeners, bulking agents, curing accelerators, foaming agents, and water-soluble polymer compounds such as polyvinyl alcohol and carboxymethylcellulose. Furthermore, when using a dispersion, adding a heat-sensitive gelling agent allows for more uniform solidification in the thickness direction by using a dry method, or by combining it with methods such as steaming or far-infrared heating. When using a solution, using a solidification modifier in combination makes it easier to obtain more uniform voids.

[0067] It is preferable to impregnate the entangled nonwoven fabric with the polymer elastomer as a solution or dispersion, and then solidify the polymer elastomer so that it creates numerous voids in a sponge-like manner, mainly by a wet method when using a solution, or mainly by a dry method when using an aqueous dispersion, thereby forming a porous layer on the entangled nonwoven fabric. In this embodiment, it is preferable to solidify the polymer elastomer by a wet method. By solidifying a polymeric elastic material impregnated into an interwoven nonwoven fabric into a sponge-like structure, a porous layer can be easily obtained. This process makes it easier to acquire a surface material that has a texture similar to natural leather, is less prone to wrinkles, or if wrinkles do occur, they easily return to their original state, and maintains a high-quality appearance.

[0068] One method for solidifying polymeric elastic materials by a wet process is to immerse them in a solidification solution at 20-60°C for 1-60 minutes, which contains a good solvent for polyurethane such as N,N-dimethylformamide, dimethylacetamide, or N-methylpyrrolidone, along with water. From the viewpoint of obtaining a surface material that is resistant to wrinkles, or that easily returns to its original state even if wrinkles occur, and that maintains a high-quality appearance, it is preferable to use a solidification solution containing N,N-dimethylformamide and water. Furthermore, the ratio of N,N-dimethylformamide to water in the solidification solution (N,N-dimethylformamide:water) is preferably 10:90 to 50:50.

[0069] <Process (4A)> Step (4A) is a step to remove marine components from the ultrafine generated fibers. By removing marine components from ultrafine generated fibers, the ultrafine generated fibers can be converted into fiber bundles of ultrafine fibers. This makes it possible to obtain a fiber base material containing ultrafine fibers. Process (4A) may be performed before process (3) or after process (3). Performing step (4A) after step (3) is preferable because the marine components are removed, creating voids between the ultrafine fiber bundles and the polymeric elastic material, and the restraint of the ultrafine fiber bundles by the polymeric elastic material weakens, resulting in a softer texture for the surface material.

[0070] One method for removing marine-derived resins is to use a solvent or decomposing agent that can selectively remove only marine-derived resins. If the marine components are water-soluble resins such as polyvinyl alcohol-based resins, water-soluble polyester resins, easily alkali-degradable modified polyester resins, polyacrylamide resins, or carboxymethylcellulose resins, the marine components can be removed with water. If the marine component is insoluble in water but soluble in organic solvents, and the island component is a polyamide resin or polyester resin, examples of organic solvents that can dissolve and remove the marine component include toluene, trichloroethylene, and tetrachloroethylene. In this embodiment, it is preferable to use toluene, which has high resin dissolving power.

[0071] <Process (4B)> Step (4B) is a step to remove island components from the hollow fiber-generating fiber. By removing island components from hollow fiber-generating fibers, the hollow fiber-generating fibers can be converted into bundles of hollow fibers. This makes it possible to obtain a fiber substrate containing hollow fibers. Process (4B) may be performed before process (3) or after process (3).

[0072] One method for removing island component resins is to use a solvent or decomposing agent that can selectively remove only the island component resins. If the island component is a water-soluble resin such as polyvinyl alcohol-based resin, water-soluble polyester resin, easily alkali-degradable modified polyester resin, polyacrylamide resin, or carboxymethylcellulose resin, the island component can be removed with water. If the island component is insoluble in water but soluble in organic solvents, and the sea component resin is a polyamide resin or polyester resin, examples of organic solvents that dissolve and remove the island component include toluene, trichloroethylene, and tetrachloroethylene. In this embodiment, it is preferable to use toluene, which has high resin dissolving power.

[0073] <Process (5)> Step (5) is a step of forming a coating layer containing a polymeric elastic material. In step (5), it is preferable to form a coating layer containing a polymeric elastic material on the fibrous substrate. Details of the polymeric elastic material used in process (5) are as described in the "Polymeric Elastic Material" section above.

[0074] Methods for forming a coating layer containing a polymeric elastic material on the surface of a fibrous substrate include, for example, a lamination method in which a resin film is formed on a release paper using a solution or dispersion containing a polymeric elastic material, the resin film is adhered to the surface of the fibrous substrate, and then the release paper is peeled off to form the coating layer; a method in which a solution or dispersion containing a polymeric elastic material is applied to the surface of the fibrous substrate using a gravure coater, bar coater, knife coater, comma coater, etc., and then dried. The coating layer may be embossed or otherwise molded to form the desired appearance, if necessary.

[0075] Specifically, the above lamination method involves applying a predetermined amount of a solution or dispersion containing a polymeric elastic material to a transfer release sheet such as a film or release paper, drying it into a film state or drying and solidifying it into a porous state to form a resin film, then bonding it to a fiber substrate via an adhesive such as a polyurethane adhesive, or bonding it by redissolving it using a solution or dispersion containing a polymeric elastic material, and then peeling off the release transfer sheet. When bonding via adhesive, the resin film may be bonded after pressing with a heated press roll (at room temperature to 130°C) as needed, allowing the adhesive to penetrate into the fiber substrate. In this case, the degree of adhesive penetration can be adjusted by adjusting the heating temperature. It is also possible to adjust the degree of adhesive penetration by changing the temperature dependence of softening due to heat by adjusting the melt viscosity of the resin constituting the adhesive.

[0076] In a method of forming a material by applying a solution or dispersion containing a polymeric elastic material to the surface of a fibrous substrate and drying it, after application, a method of drying to a film state by a dry method or solidifying and drying to a porous state may be employed, or a method of solidifying and drying to a porous state by a wet method may be employed.

[0077] The solution or dispersion containing the polymer elastomer used to form the resin film described above, and the solution or dispersion containing the polymer elastomer used to coat the surface of a fiber substrate, may contain, in addition to the polymer elastomer, known additives such as thickeners, curing accelerators, fillers, light stabilizers, antioxidants, ultraviolet absorbers, fluorescent agents, mold inhibitors, flame retardants, penetrating agents, surfactants, water-soluble polymer compounds such as polyvinyl alcohol and carboxymethylcellulose, dyes, pigments, adhesives, etc.

[0078] The coating layer containing the polymeric elastic material may be formed as a single layer or as two or more layers. When the coating layer containing the polymer elastomer consists of two or more layers, the polymer elastomer solution used to form each layer may be the same or may contain different components.

[0079] [school bag] The school bag according to an embodiment of the present invention is a school bag using the surface material according to an embodiment of the present invention. The surface material according to the embodiment of the present invention is resistant to wrinkles, or if wrinkles do occur, they easily return to their original state, and maintains a high-quality appearance. In particular, when used on the shoulder straps and flaps of school bags, it can give the school bag a lasting high-quality appearance.

[0080] [Backpack] The backpack of this embodiment is a backpack using the outer material of this embodiment. The backpack of this embodiment includes a box-shaped body with an opening on the top surface or from the top surface to the upper front for loading and unloading luggage into the storage compartment when in use, and a belt member such as a shoulder strap attached to the body for securing the bag to the user's body. Preferably, the body has sufficient strength to maintain its box shape in order to protect the luggage stored within the intended use. The box shape of the main body is preferably generally rectangular or square in the front view and top view in the state of use, and if it is rectangular, it is preferably long in the height direction or long in the width direction in the front view. The dimensions of the housing portion of the main body are preferably 20 to 29 cm, more preferably 22 to 27 cm, in the short-side direction in the front view, and preferably 9 to 18 cm, more preferably 11 to 16 cm, in the short-side direction in the top view. The belt members are attached to either the top, back, or bottom surface of the main body, and there are one or two of them. The backpack of this embodiment may include a flap that can cover the entire opening and is also openable and closable. The cover may cover the entire opening and extend to the front of the main body, or it may cover more than half of the front of the main body. The surface material of this embodiment is resistant to wrinkles, or if wrinkles do occur, they easily return to their original state, and maintains a high-quality appearance. Therefore, it can be suitably used as the surface material for belt components such as shoulder straps, flaps, and the main body other than the back, and is particularly preferred for use as the surface material for belt components such as shoulder straps and flaps. In this case, from the viewpoint of creating a high-quality appearance, the surface material is preferably leather-like in appearance. [Examples]

[0081] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited in any way by the content of the examples.

[0082] [Measurement and evaluation methods] Various physical properties were measured using the following method. The results are shown in Table 1.

[0083] <Thickness of polyurethane porous layer and coating layer> The thickness of the porous layer was measured by cutting out a section of the obtained surface material and magnifying its cross-section 50 times using an electron microscope. The thickness of the surface layer was measured by magnifying the same area 100 times. However, if the thickness of the surface layer was 10 μm or less, it was measured at 200 times magnification.

[0084] <Maximum height difference between convex and concave parts> Three randomly selected locations on the surface of the obtained surface material (coating layer side surface) were measured at 40x magnification using a Keyence VR-3000 3D surface shape measuring machine. The obtained measurements were filtered with no low-pass filter (S-filter) and with a 1mm high-pass filter (L-filter) to obtain the maximum height (Rz). The average of the three obtained maximum heights (Rz) was calculated and used as the maximum height difference between the convex and concave parts of the surface material.

[0085] <Arithmetic mean roughness> Three randomly selected locations on the surface of the obtained surface material (coating layer side surface) were measured at 40x magnification using a Keyence VR-3000 3D surface shape measuring instrument. The obtained measurements were filtered with no low-pass filter (S-filter) and with a 1mm high-pass filter (L-filter) to obtain the arithmetic mean roughness. The average of the arithmetic mean roughness of the three obtained locations was calculated and defined as the arithmetic mean roughness (Sa) of the surface material.

[0086] <Bending Hysteresis 2HB> Two test specimens were prepared by cutting the obtained surface material to a size of 5 cm wide and 20 cm long. One specimen was cut so that the length of the specimen aligned with the longitudinal direction of the surface material to be designated as the "longitudinal test specimen," and the other specimen was cut so that the length of the specimen aligned with the transverse direction of the surface material to be designated as the "transverse test specimen." A large bending test machine "KES-FB2-L" (Kato Tech Co., Ltd.) was used to test for a maximum curvature of ±0.4 cm. -1Under these conditions, the bending hysteresis of the longitudinal specimen and the bending hysteresis of the transverse specimen were measured once each, and the average of the measurements from the two specimens was defined as the bending hysteresis 2HB. Furthermore, bending hysteresis is a concave curvature of 0.2 cm on the surface of the skin material (coating layer side surface). -1 The value of the bending moment when bent (when bent in the front direction), and the curvature of the convex shape with a curvature of 0.2 cm. -1 These values ​​are calculated from the bending moment when the material is bent (in the opposite direction to the front direction), and rounded to one decimal place by rounding to two decimal places.

[0087] <thickness> The thickness (mm) of the obtained surface material was measured at two or more different locations approximately 2 to 5 cm apart, in accordance with Method A of JIS L1096:2020, under a pressure of 23.5 kPa. These values ​​were then averaged and rounded to one decimal place by rounding to two decimal places.

[0088] <Apparent Density> The apparent density was determined by taking two 10cm x 10cm test pieces and measuring the mass of each piece using an electronic balance. 2 The mass was converted to a unit mass, and the calculation was performed using the average value and the thickness of the test specimen.

[0089] <Wrinkle evaluation> The obtained surface material was cut into 6 cm long and 2 cm wide test pieces, ensuring that the longitudinal and length directions of the surface material were aligned. Each test piece was folded in half at the center in the length direction so that the surface on the coating layer side was concave, and a 500 g weight was placed on top and left to stand for 5 minutes. After that, the weight was removed, and the test pieces were visually observed after 24 hours, and the wrinkle condition was judged according to the following criteria. A: No wrinkles visible to the naked eye have formed. B: There is at least one wrinkle visible to the naked eye, but it is not noticeable and does not detract from the luxurious feel. C: At least one wrinkle is visible to the naked eye, and this wrinkle is noticeable, detracting from the sense of luxury. Furthermore, the surface materials that meet the above evaluation criteria are less prone to wrinkles, or if wrinkles do occur, they easily return to their original state, thus maintaining a high-quality appearance even when used as shoulder straps or flaps for school bags, etc.

[0090] <Gare bending rebound properties> From the obtained surface material, ten test pieces measuring 38 mm in length and 25 mm in width were cut out so that the length direction of the test piece and the longitudinal direction of the surface material were aligned, and these were designated as "longitudinal test pieces." In addition, from the obtained surface material, ten test pieces measuring 38 mm in length and 25 mm in width were cut out so that the length direction of the test piece and the transverse direction of the surface material were aligned, and these were designated as "transverse test pieces." Using the obtained "longitudinal test specimens" and "transverse test specimens," the Gaury bending resilience was measured according to JIS L1096:2020, 8.22 Bending Resilience, Method A. Of the "longitudinal test specimens," the Gaury bending resilience was measured on the side of the coating layer of the surface material for 5 specimens, and the average value was taken as the "longitudinal Gaury bending resilience on the front side." For the remaining 5 specimens, the Gaury bending resilience was measured on the side opposite to the coating layer of the surface material, and the average value was taken as the "longitudinal Gaury bending resilience on the back side." Similarly, of the "transverse test specimens," the Gaury bending resilience was measured on the side of the coating layer of the surface material for 5 specimens, and the average value was taken as the "transverse Gaury bending resilience on the front side." For the remaining 5 specimens, the Gaury bending resilience was measured on the side opposite to the coating layer of the surface material, and the average value was taken as the "transverse Gaury bending resilience on the back side."

[0091] [Example 1] A sea-island type composite fiber with a fineness of 15 dtex was produced by melt-spinning 50 parts by mass of polyethylene (sea component) and 50 parts by mass of polyamide 6 (island component) in the same melt system. This sea-island type composite fiber was stretched to 2.5 times its original length, crimped, and then cut to a fiber length of 51 mm. The resulting staples were opened with a card and formed into a fiber web with a cross-wrapper weaver. These fiber webs were stacked, needle-punched, heated to 120°C, and pressed with a calender roll to produce a material with a thickness of 2.3 mm and a basis weight of 600 g / m². 2 Therefore, a tangled nonwoven fabric with a smooth surface was created.

[0092] Next, the entangled nonwoven fabric was immersed in a dimethylformamide (DMF) solution containing 15% by mass of polyester polyurethane (1), which was obtained by polymerizing polyethylene adipate (PEA), 4,4'-diphenylmethane diisocyanate (MDI), and ethylene glycol (EG) (nitrogen atom content: 4.5 mol%, number average molecular weight (polystyrene equivalent, the same applies hereafter): 350,000), and polyether polyurethane (B), obtained by polymerizing polyethylene glycol (PEG), MDI, and EG (nitrogen atom content: 4.0 mol%, number average molecular weight: 300,000), in a mass ratio of (A):(B)=8:2, thereby impregnating the entangled nonwoven fabric with the polyester polyurethane (1). Immediately afterward, a DMF solution containing 25% by mass of polyester polyurethane (2) (nitrogen atom content: 3.5 mol%, number average molecular weight: 300,000), obtained by polymerizing PEA, MDI, and EG, was applied to the surface of the entangled nonwoven fabric at a rate of 150 g / m². 2 The polyester-based polyurethane (2) was applied and impregnated into the entangled nonwoven fabric.

[0093] Next, a DMF solution containing 20% ​​by mass of polycarbonate-based polyurethane (100% modulus: 4 MPa, nitrogen atom content: 3.0 mol%, number average molecular weight: 300,000), obtained by polymerizing a polymer diol containing polyhexamethylene carbonate glycol (PHC) as the main component (50% by mass or more), a diisocyanate containing MDI as the main component (50% by mass or more), and a chain extender containing EG as the main component (50% by mass or more), is applied to the surface of the entangled nonwoven fabric at a rate of 370 g / m². 2 It was applied. The resulting entangled nonwoven fabric was immersed in a coagulation solution of DMF / water = 20 / 80 for 30 minutes to wet-coagulate the polycarbonate-based polyurethane into a porous state. Next, after washing with water, polyethylene in the sea-island composite fibers was extracted and removed using toluene to convert it into ultrafine fibers made of polyamide 6 with an average fineness of 0.01 dtex. A 1.6 mm thick fibrous base material was obtained in which a polyurethane porous layer was formed on an entangled nonwoven fabric consisting of fiber bundles of ultrafine polyamide 6 fibers.

[0094] A DMF solution containing 15 parts by mass of polyester polyurethane (nitrogen atom content: 2.5 mol%, number average molecular weight: 300,000) obtained by polymerizing PEA, MDI, and EG with 100 parts by mass of DMF, 3 parts by mass of yellow pigment, and 1 part by mass of titanium dioxide was applied to the surface of the fibrous substrate using a 200-mesh gravure roll and dried to form a non-porous coating layer with a thickness of approximately 5 μm, thereby obtaining a surface material. The total thickness of the polyurethane porous layer and the non-porous layer (coating layer) was approximately 200 μm.

[0095] [Example 2] A sea-island composite fiber with a fineness of 10 dtex was produced by melt-spinning 50 parts by mass of polyethylene (sea component) and 50 parts by mass of polyamide 6 (island component) in the same melt system. This sea-island composite fiber was stretched to 2.5 times its original length, crimped, and then cut to a fiber length of 51 mm. The resulting staples were opened with a card and formed into a fiber web with a cross-wrapper weaver. This fiber web was stacked, needle-punched, heated to 120°C, and pressed with a calender roll to produce a material with a thickness of 1.9 mm and a basis weight of 540 g / m². 2 A tangled nonwoven fabric with a smooth surface was created.

[0096] Next, the entangled nonwoven fabric was immersed in a DMF solution containing 20% ​​polyether-based polyurethane (nitrogen atom content: 5.0 mol%, number average molecular weight: 300,000) obtained by polymerizing a polymer diol mainly composed of polytetramethylene ether glycol (PTMG) and chain extenders mainly composed of MDI and EG. After that, it was immersed in a coagulation solution of DMF / water = 25 / 75 to wet-coagulate the polyether-based polyurethane into a porous state. Next, polyethylene in the sea-island composite fibers was extracted and removed using toluene, converting it into ultrafine fibers with an average fineness of approximately 0.008 dtex, and a fiber base material with a thickness of 1.3 mm was obtained.

[0097] Next, a polyurethane top layer solution containing 100 parts by mass of the non-yellowing polycarbonate polyurethane solution "Rezamin ME8116" (manufactured by Dainichi Seika Kogyo Co., Ltd., 30% resin content), 20 parts by mass of the black pigment "Rezamin DUT4790" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 30 parts by mass of DMF, and 30 parts by mass of methyl ethyl ketone (MEK) was applied to the release paper "AR-138" (manufactured by Asahi Roll Co., Ltd.) and dried to form a resin film 1 that would become the top layer of the coating layer. The thickness of the obtained resin film 1 was 15 μm. Next, a polyurethane-based intermediate layer solution containing 100 parts by mass of one-component polyether-based polyurethane "Rezamin ME8106" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 20 parts by mass of black pigment "Rezamin DUT4790" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 30 parts by mass of DMF, and 30 parts by mass of MEK was applied to the resin film 1 and dried to form a resin film 2 which would become the intermediate layer of the coating layer. The total thickness of the obtained resin film 1 and resin film 2 (total of the top layer and intermediate layer of the coating layer) was 35 μm. Next, 100 parts by mass of the cross-linked polyurethane adhesive "UD8310" (manufactured by Dainichi Seika Co., Ltd.), 10 parts by mass of the cross-linking agent "Rezamin NE Cross-linking Agent" (manufactured by Dainichi Seika Co., Ltd.), 2 parts by mass of the cross-linking accelerator "Rezamin HI-299" (manufactured by Dainichi Seika Co., Ltd.), 25 parts by mass of DMF, and 15 parts by mass of ethyl acetate were mixed to prepare a polyurethane adhesive solution. The obtained polyurethane adhesive solution was applied to the surface of the resin film 2, which will be the intermediate layer of the coating layer, at a rate of 130 g / m². 2 The material was applied and dried at 120°C for 15 seconds to evaporate the solvent, obtaining a resin film containing an adhesive layer. Next, the adhesive layer of the resin film and the fiber substrate were bonded together, and the resin film containing the fiber substrate and adhesive layer was pressed together using a metal press roll with a roll clearance of 0.9 mm, which is approximately 65% ​​of the total thickness of the fiber substrate portion (1.4 mm). This allowed the polyurethane adhesive to penetrate the porous polyurethane layer, and a laminate was obtained. The obtained laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days, and the release paper was peeled off to obtain the surface material.

[0098] [Example 3] A sea-island composite fiber with a fineness of 10 dtex was produced by melt-spinning 45 parts by mass of polyamide 6 (sea component) and 55 parts by mass of polystyrene (island component) in the same melt system. This sea-island composite fiber was stretched three times to impart crimp, and then cut to a fiber length of 51 mm. The resulting staples were opened with a card, and a fiber web was formed with a cross-wrapper weaver. This fiber web was stacked and needle-punched, then immersed in an aqueous solution containing 4% by mass of polyvinyl alcohol, dried, and the surface was buffed to produce a fiber with a thickness of 1.4 mm and a basis weight of 300 g / m². 2 A tangled nonwoven fabric with a smooth surface was created.

[0099] Next, the entangled nonwoven fabric was immersed in a DMF solution containing 15% by mass of polyester polyurethane (100% modulus: 10 MPa, nitrogen atom content: 4.0 mol%, number average molecular weight: 300,000) obtained by copolymerizing PEA, MDI, and EG, thereby impregnating the entangled nonwoven fabric with the polyester polyurethane. Immediately afterward, a DMF solution containing 25% by mass of a polymer diol obtained by copolymerizing PHC and polybutylene adipate (PBA) (copolymerization molar ratio PHC:PBA=6:4), and a polycarbonate-based polyurethane (100% modulus: 10 MPa, nitrogen atom content: 3.0 mol%, number average molecular weight: 300,000) obtained by polymerizing MDI and EG, was applied to the surface of the entangled nonwoven fabric at a rate of 340 g / m². 2 The polycarbonate-based polyurethane was applied and impregnated into the entangled nonwoven fabric. Furthermore, a DMF solution containing 20% ​​by mass of the polycarbonate-based polyurethane was added at a rate of 600 g / m². 2 It was applied. The resulting entangled nonwoven fabric was immersed in a coagulation solution (40°C) with a DMF / water ratio of 30 / 70 for 30 minutes to solidify the coated polycarbonate-based polyurethane into a porous state.

[0100] Next, after washing with water, the polystyrene in the sea-island composite fibers was extracted and removed using toluene to convert them into porous fibers, and a 1.6 mm thick fibrous substrate was obtained in which a polyurethane porous layer was formed on an entangled nonwoven fabric made of polyamide 6 porous fibers. The thickness of the polyurethane porous layer was approximately 400 μm.

[0101] Next, the surface of the polyurethane porous layer laminated on the fiber substrate was buffed using 180-grit sandpaper to remove a portion of the polyurethane porous layer formed on the outermost surface. The thickness removed at this time was approximately 1 μm. Furthermore, the back surface, which is opposite the polyurethane porous layer, was buffed using 180-grit sandpaper to obtain a buffed fiber substrate with a thickness of 1.1 mm.

[0102] Next, a polyurethane top layer solution containing 100 parts by mass of non-yellowing polycarbonate polyurethane solution "Rezamin NES9022-15" (manufactured by Dainichi Seika Kogyo Co., Ltd., resin content 25% by mass), 20 parts by mass of black pigment "Seika Seven BS-780" (manufactured by Dainichi Seika Kogyo Co., Ltd.), and 30 parts by mass of MEK was applied to release paper "DE-35" (manufactured by Dai Nippon Printing Co., Ltd.), and dried to form a resin film 3 which would become the top layer of the coating layer. The thickness of the resin film 3 was 15 μm. Next, a polyurethane-based intermediate layer solution containing 100 parts by mass of one-component polyether-based polyurethane "Rezamin ME8116" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 20 parts by mass of black pigment "Rezamin DUT4790" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 30 parts by mass of DMF, and 30 parts by mass of MEK was applied to the resin film 3 and dried to form a resin film 4 that would become the intermediate layer of the coating layer. The total thickness of the obtained resin films 3 and 4 (total of the top layer and intermediate layer of the coating layer) was 35 μm. Next, a polyurethane adhesive solution was prepared by mixing 100 parts by mass of the cross-linked polyurethane adhesive "TA205FT" (manufactured by DIC Corporation), 10 parts by mass of the cross-linking agent "Takenate D110N" (manufactured by Mitsui Chemicals, Inc.), 2 parts by mass of the cross-linking accelerator "Crisbon Accel QS" (manufactured by DIC Corporation), 30 parts by mass of DMF, and 10 parts by mass of ethyl acetate. The obtained polyurethane adhesive solution was then applied to the surface of the resin film 4, which would become the intermediate layer of the coating layer, at a rate of 130 g / m². 2 The material was applied and dried at 120°C for 15 seconds to evaporate the solvent, obtaining a resin film containing an adhesive layer. Next, the adhesive layer of the resin film was bonded to the polyurethane porous layer side of the buffed fiber substrate. Using a metal press roll with a roll clearance of 0.8 mm, which is approximately 65% ​​of the total thickness (1.2 mm) of the polyurethane porous layer in the buffed fiber substrate and the fiber substrate portion without the polyurethane porous layer, the buffed fiber substrate and the resin film including the adhesive layer were pressed together, allowing the polyurethane adhesive to penetrate the polyurethane porous layer and obtain a laminate. The obtained laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days, and the release paper was peeled off to obtain a surface material.

[0103] [Example 4] A buffed fiber substrate with a thickness of 1.1 mm was obtained using the same method as in Example 3. Next, a polyurethane top layer solution containing 100 parts by mass of the non-yellowing polyether polyurethane solution "Rezamin ME8116" (manufactured by Dainichi Seika Kogyo Co., Ltd., 30% resin content), 20 parts by mass of the black pigment "Rezamin DUT4790" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 30 parts by mass of DMF, and 30 parts by mass of MEK was applied to the release paper "DE-35" (manufactured by Dai Nippon Printing Co., Ltd.), and dried to form a resin film 5 that would become the top layer of the coating layer. The thickness of the resin film 5 was 15 μm. Next, a polyurethane-based intermediate layer solution containing 100 parts by mass of one-component polyether-based polyurethane "Rezamin ME8106" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 20 parts by mass of black pigment "Rezamin DUT4790" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 30 parts by mass of DMF, and 30 parts by mass of MEK was applied to the resin film 5 and dried to form a resin film 6 that would become the intermediate layer of the coating layer. The total thickness of the obtained resin film 5 and resin film 6 (total of the top layer and intermediate layer of the coating layer) was 35 μm. Next, 100 parts by mass of the cross-linked polyurethane adhesive "UD8310" (manufactured by Dainichi Seika Co., Ltd.), 10 parts by mass of the cross-linking agent "Rezamin NE Cross-linking Agent" (manufactured by Dainichi Seika Co., Ltd.), 2 parts by mass of the cross-linking accelerator "Rezamin HI-299" (manufactured by Dainichi Seika Co., Ltd.), 25 parts by mass of DMF, and 15 parts by mass of ethyl acetate were mixed to prepare a polyurethane adhesive solution. The obtained polyurethane adhesive solution was applied to the surface of the resin film 6, which will be the intermediate layer of the coating layer, at a rate of 130 g / m². 2 The material was applied and dried at 120°C for 15 seconds to evaporate the solvent, obtaining a resin film containing an adhesive layer. Next, the adhesive layer of the resin film and the polyurethane porous layer side of the fiber substrate were bonded together. Using a metal press roll with a roll clearance of 0.8 mm, which is approximately 65% ​​of the total thickness of the polyurethane porous layer and the fiber substrate portion without the polyurethane porous layer (1.2 mm), the resin film including the fiber substrate and the adhesive layer was pressed together, allowing the polyurethane adhesive to penetrate the polyurethane porous layer and obtain a laminate. The obtained laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days, and the release paper was peeled off to obtain a surface material.

[0104] [Example 5] Using the same method as in Example 3, a 1.6 mm thick fiber substrate was obtained in which a polyurethane porous layer was formed on an entangled nonwoven fabric made of porous fibers made of polyamide 6. Next, a DMF solution containing 12 parts by mass of polyester polyurethane (100% modulus: 10 MPa, nitrogen atom content: 2.5 mol%, number average molecular weight: 300,000) obtained by polymerizing PEA, MDI, and EG, 5 parts by mass of carbon black, and 83 parts by mass of DMF was applied to the porous polyurethane layer of the fiber substrate using a 150-mesh gravure roll and dried to form a coating layer with a thickness of approximately 10 μm. Next, an embossed pattern, including a textured surface, was formed on the fibrous substrate having a coating layer by using an embossing roll with a leather-like pattern at a temperature of 170°C, a pressure of 15 kg / cm, and a processing speed of 1.5 m / min. Furthermore, the back surface was buffed with 180-grit sandpaper to adjust the thickness to 1.3 mm to obtain the surface material.

[0105] [Comparative Example 1] A sea-island composite fiber with a fineness of 10 dtex was produced by melt-spinning 45 parts by mass of polyamide 6 (sea component) and 55 parts by mass of polystyrene (island component) in the same melt system. This sea-island composite fiber was stretched three times, crimped by applying a fiber oil, and then cut to a fiber length of 51 mm. The resulting staples were opened with a card and formed into a fiber web with a cross-wrapper weaver. This fiber web was stacked and needle-punched, then immersed in an aqueous solution containing 4% by mass of polyvinyl alcohol, dried, and the surface was buffed to produce a fiber with a thickness of 1.4 mm and a basis weight of 390 g / m². 2 A tangled nonwoven fabric with a smooth surface was obtained.

[0106] Next, the entangled nonwoven fabric was immersed in a DMF solution containing a total of 15% by mass of polymer diol obtained by copolymerizing PHC and PBA, and polycarbonate-based polyurethane (100% modulus: 10 MPa, nitrogen atom content: 3.0 mol%, number average molecular weight: 300,000) obtained by polymerizing MDI and EG, thereby impregnating the entangled nonwoven fabric with the polycarbonate-based polyurethane. Immediately thereafter, a DMF solution containing 25% by mass of the aforementioned polycarbonate-based polyurethane is applied to the surface of the entangled nonwoven fabric at a rate of 340 g / m². 2The polycarbonate-based polyurethane was applied and impregnated into the entangled nonwoven fabric. Furthermore, a DMF solution containing 20% ​​by mass of the polycarbonate-based polyurethane was added at a rate of 600 g / m². 2 It was applied. The resulting entangled nonwoven fabric was immersed in a coagulation solution (40°C) with a DMF / water ratio of 30 / 70 for 30 minutes to solidify the coated polycarbonate-based polyurethane into a porous state.

[0107] Next, after washing with water, the polystyrene in the sea-island composite fibers was extracted and removed using toluene to convert them into porous fibers, and a 1.6 mm thick fibrous substrate was obtained in which a polyurethane porous layer was formed on an entangled nonwoven fabric made of polyamide 6 porous fibers. The thickness of the polyurethane porous layer was approximately 400 μm.

[0108] Next, the surface of the polyurethane porous layer laminated in the fiber substrate was buffed using 180-grit sandpaper to remove a portion of the polyurethane porous layer formed on the outermost surface. The thickness removed at this time was approximately 1 μm. Furthermore, the back surface, which is opposite the polyurethane porous layer, was buffed using 180-grit sandpaper to obtain a buffed fiber substrate with a thickness of 1.6 mm.

[0109] Next, a resin film containing an adhesive layer was obtained using the same method as in Example 3. Next, the adhesive layer of the resin film and the polyurethane porous layer side of the buffed fiber substrate were bonded together. Using a metal press roll with a roll clearance of 1.4 mm, which is approximately 65% ​​of the total thickness (1.7 mm) of the polyurethane porous layer in the buffed fiber substrate and the fiber substrate portion without the polyurethane porous layer, the buffed fiber substrate and the resin film including the adhesive layer were pressed together, allowing the polyurethane adhesive to penetrate the polyurethane porous layer and obtain a laminate. The obtained laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days, and the release paper was peeled off to obtain a surface material.

[0110] [Comparative Example 2] Using the same method as in Example 3, a 1.6 mm thick fibrous substrate was obtained in which a polyurethane porous layer was formed on an entangled nonwoven fabric made of porous polyamide 6 fibers. The thickness of the polyurethane porous layer was approximately 400 μm. Next, a DMF solution containing 30 parts by mass of the black pigment "Seika Seven BS-780" (manufactured by Dainichi Seika Co., Ltd., 20% by mass of carbon black, 9% by mass of polycarbonate polyurethane, 71% by mass of DMF) and 70 parts by mass of the silicone-modified polycarbonate polyurethane solution "Rezamin NES9022-15" (manufactured by Dainichi Seika Kogyo Co., Ltd., 25% by mass of resin, 75% by mass of DMF) was applied onto the polyurethane porous layer of the fiber substrate using a 150-mesh gravure roll to form a non-porous coating layer with a thickness of approximately 15 μm. Next, 18 recesses / mm² with an average depth of 60 μm are made in the fibrous substrate having a coating layer. 2 An embossed pattern, including the uneven surface, was formed on the coating layer by using an embossing roll with a fine uneven pattern across its entire surface, at a temperature of 170°C, a pressure of 15 kg / cm, and a processing speed of 1.5 m / min. Next, the back surface, which is opposite the coating layer, was buffed with 180-grit sandpaper to obtain a 1.2 mm thick surface material with the coating layer.

[0111] [Comparative Example 3] After melt-spinning polyamide 6, it was stretched three times, crimped with a fiber oil, dried, and cut to a fiber length of 51 mm to obtain 2.5 dtex staples. Separately, after melt-spinning polyethylene terephthalate, it was stretched four times, crimped with a fiber oil, dried, and cut to a fiber length of 51 mm to obtain 1.5 dtex staples. Then, the polyamide 6 staples and polyethylene terephthalate staples were blended by weight in a 50:50 ratio, opened with a card, and a fiber web was produced. This fiber web is layered, needle-punched, immersed in an aqueous solution containing 4% by mass of polyvinyl alcohol, dried, and then buffed to achieve a thickness of approximately 1.4 mm and a basis weight of 400 g / m². 2 An entangled nonwoven fabric was obtained.

[0112] Next, the entangled nonwoven fabric was immersed in a DMF solution containing a total of 15% by mass of polyester polyurethane (100% modulus: 10 MPa, nitrogen atom content: 4.5 mol%, number average molecular weight: 350,000) obtained by copolymerizing PEA, MDI, and EG (copolymerization molar ratio: PHC:PBA = 6:4), thereby impregnating the entangled nonwoven fabric with the polyester polyurethane. The resulting entangled nonwoven fabric was immersed in a coagulation solution (40°C) with a DMF / water ratio of 30 / 70 for 30 minutes to solidify the polyester-based polyurethane into a porous state. Next, a fused nonwoven fabric made by solidifying polyester polyurethane into a porous structure was washed with water, then immersed in an aqueous solution containing 1.5% by mass of ethylenebis-stearamide, and dried to obtain a 1.2 mm thick fibrous base material consisting of a fused nonwoven fabric of polyamide staples and polyethylene terephthalate staples.

[0113] Next, a DMF solution containing a total of 25% by mass of polycarbonate-based polyurethane (100% modulus: 10 MPa, nitrogen atom content: 3.0 mol%, number average molecular weight: 300,000) obtained by copolymerizing polymer diols (polymerization molar ratio of PHC:PBA = 6:4), MDI, and EG was applied to the surface of the entangled nonwoven fabric at a rate of 600 g / m². 2 It was applied. The resulting entangled nonwoven fabric was immersed in a coagulation solution (40°C) of DMF / water = 30 / 70 for 30 minutes, and the coated polycarbonate-based polyurethane was wet-coagulated into a porous state, thereby obtaining a fibrous base material in which a polyurethane porous layer was formed on the entangled nonwoven fabric.

[0114] Next, a resin film containing an adhesive layer was obtained using the same method as in Example 4. Next, the adhesive layer of the resin film and the polyurethane porous layer side of the fiber substrate were bonded together. Using a metal press roller with a roll clearance of 0.8 mm, which is approximately 65% ​​of the total thickness of the fiber substrate and the porous coating layer (1.2 mm), the resin film including the fiber substrate and adhesive layer was pressed together, allowing the polyurethane adhesive to penetrate the polyurethane porous layer and obtain a laminate. The obtained laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days. After peeling off the release paper, the back side (the side without the coating layer) was buffed with 180-grit sandpaper to remove 0.7 mm of the back side, obtaining a surface material.

[0115] [Comparative Example 4] In Comparative Example 3, the laminate was dried at 130°C for 3 minutes, then aged at 50°C for 3 days, and after peeling off the release paper, the surface material was obtained in the same manner as above, except that the back surface was not buffed.

[0116] [Table 1]

[0117] As shown in Table 1, the surface materials obtained in Examples 1 to 5 that satisfy formulas (I) and (II) are less prone to wrinkles, or if wrinkles do occur, they easily return to their original state, and the high-quality appearance is maintained. On the other hand, the surface materials obtained in Comparative Examples 1 to 4, which do not satisfy formulas (I) and (II), are prone to wrinkles, and even if wrinkles occur, they easily return to their original state, indicating that they are surface materials that do not maintain a high-quality appearance.

Claims

1. A surface material whose bending hysteresis 2HB (gf・cm / cm) and thickness h (mm) when bent in the front direction satisfy the following formulas (I) and (II). 2HB≦15h-10 (I) 1.0≦h≦2.5 (II)

2. The surface material according to claim 1, used for one or more selected from shoulder straps and flaps.

3. The surface material according to claim 1 or 2, having an embossed surface, wherein the maximum height difference between the convex and concave portions of the embossed surface is 120 μm or less.

4. The surface material according to claim 1 or 2, wherein the arithmetic mean roughness is 10 μm or less.

5. The surface material according to claim 1 or 2, which is arranged on the external surface side.

6. The outer material according to claim 1 or 2, for use in school bags.

7. A backpack using the surface material described in claim 1 or 2.

Images