阅读说明：本技术 合成皮革 (Synthetic leather ) 是由 大崎和孝 池田祥太郎 于 2020-01-22 设计创作，主要内容包括：本发明提供一种满足国际标准EN45545-2中的发热特性、发烟特性并且作为座椅用表皮材料的耐久性、椅子张紧特性优异的合成皮革。本发明的合成皮革是至少层叠纤维基材、树脂层而成的合成皮革,其构成为,合成皮革的有机质量为400g/m<Sup>2</Sup>以下,树脂层中含有的阻燃剂包含磷系阻燃剂,树脂层中的树脂包含聚碳酸酯系聚氨酯树脂。(The invention provides synthetic leather which satisfies the heat generation characteristics and the smoke emission characteristics of the international standard EN45545-2 and has excellent durability and chair tension characteristics as a seat skin material. The synthetic leather of the present invention is a synthetic leather obtained by laminating at least a fiber base material and a resin layer, and is configured such that the organic mass of the synthetic leather is 400g/m 2 Hereinafter, the flame retardant contained in the resin layer includes a phosphorus flame retardant, and the resin in the resin layer includes a polycarbonate-based polyurethane resin.)

1. A synthetic leather characterized by being a synthetic leather obtained by laminating at least a fiber base material and a resin layer,

the organic mass of the synthetic leather was 400g/m²In the following, the following description is given,

the flame retardant contained in the resin layer contains a phosphorus-based flame retardant,

the resin in the resin layer contains a polycarbonate-based polyurethane resin.

2. The synthetic leather according to claim 1, wherein the mass of the fibrous base material is 350g/m²The following.

Technical Field

The present invention relates to a synthetic leather.

Background

Worldwide, the application of international standard EN45545-2 to a skin material used as an interior material for railways is increasing. In particular, the heat generation property and the smoke emission property in this standard are emphasized.

On the other hand, although not described in international standard EN45545-2, a skin material excellent in durability and chair stretch property is generally required for a seat skin material used as an interior material for railways.

For example, as described in patent document 1, synthetic leather having good appearance and durability suitable for automotive interior applications when used in a vehicle seat has been proposed.

Disclosure of Invention

Problems to be solved by the invention

However, the synthetic leather described in patent document 1 has a problem that it is difficult to satisfy the heat generation characteristics and the smoke emission characteristics in international standard EN 45545-2.

The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a synthetic leather which satisfies heat generation characteristics and smoke emission characteristics of international standard EN45545-2 and is excellent in durability and chair stretch characteristics as a seat skin material

Means for solving the problems

The synthetic leather of the present invention is characterized by being a synthetic leather obtained by laminating at least a fiber base material and a resin layer,

the organic mass of the synthetic leather was 400g/m²In the following, the following description is given,

the flame retardant contained in the resin layer contains a phosphorus-based flame retardant,

the resin in the resin layer contains a polycarbonate-based polyurethane resin.

Effects of the invention

The synthetic leather of the present invention satisfies heat generation characteristics and smoke emission characteristics in international standard EN45545-2, and is excellent in durability and chair stretch characteristics.

Drawings

Fig. 1 is a sectional view showing a first embodiment of the synthetic leather of the present invention.

Fig. 2 is a sectional view showing a second embodiment of the synthetic leather of the present invention.

Fig. 3 is a sectional view showing a third embodiment of the synthetic leather of the present invention.

Fig. 4 is a sectional view showing a fourth embodiment of the synthetic leather of the present invention.

Description of the reference numerals

10: a skin layer; 20: a fibrous base material; 30: a protective layer; 40: an adhesive layer; 50: bonding a foaming layer; 60: a foamed layer; 70: a resin layer; 100. 110, 120, 130: synthesizing leather; 210: a longitudinal line; 220: and (6) transverse lines.

Detailed Description

The synthetic leather of the present invention is characterized by being a synthetic leather obtained by laminating at least a fiber base material and a resin layer,

the organic mass of the synthetic leather was 400g/m²In the following, the following description is given,

the flame retardant contained in the resin layer contains a phosphorus-based flame retardant,

the resin in the resin layer contains a polycarbonate-based polyurethane resin.

Hereinafter, each structure of the synthetic leather of the present invention will be described in further detail.

The surface of the resin layer in the synthetic leather can be given a leather-like appearance by appropriately giving a mottled pattern or the like.

(synthetic leather)

The synthetic leather of the present invention is a synthetic leather obtained by laminating at least a fiber base material and a resin layer, and has an organic mass of 400g/m²The following. By bringing the organic mass to 400g/m²Hereinafter, the heat generation characteristic of International Standard EN45545-2 can be set to a standard value of 50kW/m²The following. From this viewpoint, the organic mass is preferably 350g/m²Hereinafter, more preferably 300g/m²The following. Furthermore, by making the organic mass 200g/m²As described above, the mechanical strength such as tensile strength and tear strength required for synthetic leathers can be reliably ensured.

Here, the "organic mass of the synthetic leather" refers to a mass per unit area of only solid organic substances when all solid components constituting the synthetic leather are divided into organic substances and inorganic substances.

The synthetic leather of the present invention may contain not only organic materials but also inorganic materials. When the inorganic material is contained, the inorganic material is preferably contained in an amount of 25 parts by mass or less based on 100 parts by mass of the total solid components constituting the synthetic leather. By containing the inorganic material within the above range, flame retardancy can be improved while mechanical strength (e.g., tensile strength) of the synthetic leather is well maintained.

Here, the "inorganic mass of the synthetic leather" refers to the mass per unit area of only solid inorganic substances when all solid components constituting the synthetic leather are divided into organic substances and inorganic substances.

(resin layer)

The flame retardant contained in the resin layer in the present invention includes a phosphorus flame retardant. When the flame retardant contained in the resin layer contains a phosphorus-based flame retardant, the standard value can be set to 200 or less in the smoke emission characteristics in international standard EN 45545-2. This is because the phosphorus-based flame retardant has a property of forming a carbide film during combustion to block oxygen, and thus has excellent flame retardancy and is less likely to smoke. From the viewpoint of improving the smoke emission characteristics, the phosphorus-based flame retardant is preferably 50 mass% or more, more preferably 70 mass% or more, even more preferably 90 mass% or more, and particularly preferably substantially 100 mass% of the flame retardant contained in the resin layer.

Examples of the phosphorus flame retardant include triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, 2-ethylhexyl diphenyl phosphate, aromatic condensed phosphate, tris (dichloropropyl) phosphate, polyphosphate salts, and red phosphorus. The resin layer contains one kind of phosphorus flame retardant or two or more kinds of phosphorus flame retardants.

The amount of the phosphorus flame retardant added is preferably 20 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the resin constituting the resin layer. If it is less than 20 parts by mass, it becomes difficult to obtain desired flame retardancy. When the amount exceeds 70 parts by mass, the mechanical strength, texture and drapability of the synthetic leather tend to be lowered.

The resin layer in the present invention may be a single layer or may be composed of a plurality of layers. When the resin layer is composed of a plurality of layers, any one or more of the plurality of layers contains a phosphorus flame retardant. When two or more of the plurality of layers contain the phosphorus flame retardant, the total amount of the phosphorus flame retardant is preferably adjusted to 20 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the resin constituting the resin layer.

The resin in the resin layer of the present invention contains a polycarbonate-based polyurethane resin. By containing a polycarbonate-based polyurethane resin as the resin in the resin layer, synthetic leather having excellent durability can be provided. The synthetic leather of the present invention is excellent in peel strength and abrasion resistance, particularly as measured after exposure to humid heat aging conditions, which are assumed to have hydrolysis. The peel strength may be measured according to JIS K6772, and the abrasion resistance may be measured according to JIS K7204. From this viewpoint, the polycarbonate-based polyurethane resin is preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and particularly preferably substantially 100% by mass of the resin constituting 100% by mass of the resin layer. When the resin layer is formed of a plurality of layers, the polycarbonate-based polyurethane resin is preferably contained in the above ratio in the total amount of the resin contained in all the layers forming the plurality of layers.

In the case where the resin layer is composed of a plurality of layers, one layer may be composed of a polycarbonate-based polyurethane resin, the other layer may be composed of a resin other than a polycarbonate-based polyurethane resin, or any of the layers may contain a polycarbonate-based polyurethane resin and a resin other than the polycarbonate-based polyurethane resin. From the viewpoint of exhibiting excellent peel strength and abrasion resistance even under exposure to humid heat aging conditions, it is preferable that all of the layers constituting the multilayer contain a polycarbonate-based polyurethane resin, and it is more preferable that all of the multilayer be substantially composed of only a polycarbonate-based polyurethane resin.

The wet heat aging condition as used herein means that the synthetic leather is left to stand in an atmosphere of 70 ℃ and at a humidity of 95% RH for 5 to 10 weeks.

The polycarbonate-based polyurethane resin may be any resin that can be used for a resin layer of synthetic leather, and examples thereof include a non-yellowing type polycarbonate-based polyurethane resin obtained by reacting a polycarbonate diol component with a non-yellowing type diisocyanate component, a low molecular chain extender, and the like.

The polycarbonate-based polyurethane resin may be mixed with a polyether-based polyurethane resin, a polyester-based polyurethane resin, or the like, as long as the properties of the synthetic leather are not impaired.

The method for producing the resin layer made of the polycarbonate-based polyurethane resin is not particularly limited. For example, a polycarbonate-based polyurethane resin solution is prepared by dissolving a polycarbonate-based polyol, a polyisocyanate, and a phosphorus-based flame retardant in an organic solvent such as methyl ethyl ketone, toluene, or dimethylformamide, or a solvent such as water. In this case, one or more of various additives such as a conductive agent, a colorant, a filler, a light stabilizer, an ultraviolet absorber, and an antioxidant may be added as necessary. Then, the prepared polycarbonate-based polyurethane resin solution is applied to a release paper with stripes or the like and dried, thereby producing a resin layer. The polycarbonate-based polyurethane resin solution may be of a one-pack type or a two-pack type.

The resin layer in the present invention may be a single layer or may be composed of a plurality of layers. The synthetic leather of the present invention having a single-layer or multi-layer resin layer will be described with reference to fig. 1 to 4. In all the drawings, the same components are denoted by the same reference numerals, and overlapping description is omitted as appropriate. In addition, the cross sections in fig. 1 to 4 each show a cross section when the synthetic leather is cut in the thickness direction.

Fig. 1 is a cross-sectional view of a first embodiment of the synthetic leather of the present invention including a single-layered resin layer. The synthetic leather 100 shown in fig. 1 includes a resin layer 70 composed only of the skin layer 10 on one surface of the fiber base material 20. The skin layer 10 is a layer that is the main body of the resin layer 70, and the skin layer 10 contains at least a polycarbonate-based polyurethane resin. The fiber base material 20 is a layer for supporting the resin layer 70. Here, as the fiber base material 20, a knitted fabric composed of vertical threads 210 and horizontal threads 220 is illustrated. The protective layer 30 is a surface-treated layer for protecting the skin layer 10, and is optionally provided on the front surface side (the side opposite to the fiber base material 20 with the resin layer 70 interposed therebetween) of the synthetic leather of the present invention.

Fig. 2 to 4 are sectional views of second to fourth embodiments of the synthetic leather of the present invention including a plurality of resin layers.

The synthetic leather 110 shown in fig. 2 includes a resin layer 70 composed of a skin layer 10 and an adhesive layer 40. The adhesive layer 40 is a layer for bonding the skin layer 10 and the fiber base material 20. Even in the embodiment without an adhesive layer, such as the synthetic leather 100 described above, the skin layer 10 in a semi-cured state and the fiber base material 20 can be bonded by a method such as laminating them. However, the provision of the adhesive layer 40 is preferable because the peel strength of the resin layer 70 with respect to the fiber base material 20 can be increased.

The synthetic leather 120 shown in fig. 3 includes a resin layer 70 composed of a skin layer 10 and an adhesive foam layer 50. The adhesive foamed layer 50 is a foamed resin layer having adhesiveness. Therefore, the adhesive foam layer 50 can bond the skin layer 10 and the fiber base material 20, and can impart good durability to the synthetic leather 120 due to impact absorption.

The synthetic leather 130 shown in fig. 4 includes a resin layer 70 composed of a skin layer 10, a foam layer 60, and an adhesive layer 40. The foamed layer 60 is a foamed resin layer and can impart excellent durability to the synthetic leather 130 due to impact absorption. In addition, in the adhesive layer 40, the resin layer 70 is joined to the fiber base material 20 by joining the foamed layer 60 to the fiber base material 20. By providing the foaming layer 60 and the adhesive layer 40 as separate layers in this way, the contact area between the adhesive layer 40 and the fiber base material 20 can be increased as compared with the synthetic leather 120 described above. Therefore, the synthetic leather 130 shows excellent durability and shows better peel strength.

The first to fourth embodiments described above are examples of the embodiment of the present invention, and do not limit the present invention at all. Any layer may be appropriately disposed between one layer constituting the synthetic leather described above and another layer adjacent thereto without departing from the scope of the resin of the present invention.

The polycarbonate-based polyurethane resin solution used for forming the skin layer, the foam layer, the adhesive layer, or the adhesive foam layer may be either a one-pack type or a two-pack type.

In the case where the resin layer is a multilayer, the phosphorus flame retardant may be contained in any one of the skin layer, the foamed layer, the adhesive layer, and the adhesive foamed layer, and for example, the phosphorus flame retardant may be contained in a multilayer such as an adhesive layer and a foamed layer, an adhesive layer and a skin layer, a foamed layer and a skin layer, an adhesive layer and a foamed layer and a skin layer, and an adhesive foamed layer and a skin layer.

Hereinafter, each layer constituting the synthetic leather will be described in further detail.

(skin layer)

The skin-like layer is a layer constituting the surface of the synthetic leather, and can be given a leather-like appearance by appropriately giving a striped pattern or the like. The skin layer contains a polycarbonate-based polyurethane resin and may contain a phosphorus-based flame retardant. In addition, both the mode in which the skin layer is disposed on the outermost surface of the synthetic leather and the mode in which the skin layer is disposed at a position close to the outermost surface of the synthetic leather are included in the present invention. That is, the present invention includes a mode in which an arbitrary layer (for example, a protective layer) is disposed on the surface side of the skin layer.

The thickness of the skin layer is not particularly limited, and the thickness after curing is preferably 10 μm or more and 60 μm or less.

(foaming layer)

The foamed layer is laminated on the fiber base material side of the skin layer, and is a layer for imparting texture and durability to the synthetic leather. The foamed layer preferably contains a polycarbonate-based polyurethane resin, and may contain a phosphorus-based flame retardant.

The thickness of the foamed layer is not particularly limited, and the thickness after curing is preferably 200 μm to 500 μm. The foamed layer may be formed by chemical foaming in which a chemical foaming agent is foamed, or may be formed by mechanical foaming in which foaming is mechanically performed.

(adhesive layer)

The adhesive layer is a layer for bonding the fiber base material and the resin layer. The adhesive layer is a layer that bonds the fiber base material and the skin layer (see fig. 2) or bonds the fiber base material and the foam layer (see fig. 4), for example. The adhesive layer preferably contains a polycarbonate-based polyurethane resin, and may contain a phosphorus-based flame retardant.

The thickness of the adhesive layer is not particularly limited, and the thickness after curing is preferably 30 μm or more and 120 μm or less.

The adhesive layer may be formed using an adhesive containing a polycarbonate-based polyurethane resin. For example, the adhesive layer is formed by applying the adhesive to the surface of the skin layer on the side facing the fiber base material, or applying the adhesive to the surface of the foam layer on the side facing the fiber base material.

(adhesion foaming layer)

The adhesive foam layer is a layer that joins the fiber base material and the resin layer and can impart durability to the synthetic leather by absorbing impact.

For a technique of bonding a layer such as a skin layer to a fiber base material by using a bonding foaming agent, for example, a description disclosed in WO2014/192283 can be referred to.

The adhesive foam layer formed is formed by, for example, applying an adhesive foam agent to the surface of the skin layer on the side facing the fiber base material and heating the adhesive foam layer at an appropriate temperature. The adhesive foaming agent mentioned here is, for example, a polycarbonate-based polyurethane resin solution containing heat-expandable particles. The heat-expandable particles applied to the skin material or the like are foamed by heating, and form cells in the polyurethane resin.

Further, by laminating the fiber base material on the adhesive foam layer before the polyurethane resin is completely cured, the fiber base material and the skin-like layer can be adhered.

The thickness of the adhesive foam layer formed using the adhesive foam agent is not particularly limited, and the thickness after curing is preferably 50 μm or more and 1000 μm or less.

When the resin layer is a multilayer, one or more of the skin layer, the foamed layer, the adhesive layer, and the adhesive foamed layer may contain a phosphorus flame retardant.

The phosphorus flame retardant contained in the adhesive layer or the adhesive foam layer is preferably 20 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the resin constituting the adhesive layer or the adhesive foam layer. When the phosphorus flame retardant is contained in the adhesive layer or the adhesive foam layer in an amount of 20 parts by mass or more, flame retardancy can be imparted to the synthetic leather without lowering the mechanical strength such as abrasion resistance and bendability inherent in the resin layer (hereinafter, this may be referred to as "flame-retardant adhesive layer effect 1"). When the content ratio of the phosphorus flame retardant is 20 parts by mass or more, the synthetic leather can be made to exhibit a desired color tone without adversely affecting the color developability in the skin-like layer containing a pigment (hereinafter, may be referred to as "flame-retardant adhesive layer effect 2").

On the other hand, when the phosphorus flame retardant is contained in the adhesive layer or the adhesive foam layer in an amount of more than 70 parts by mass, the adhesiveness required for the adhesive layer may be insufficient, and the peel strength may be reduced, so that the physical properties as synthetic leather may not be secured.

In particular, the phosphorus-based flame retardant contained in the adhesive layer or the adhesive foam layer is preferably 50 mass% or more, more preferably 70 mass% or more, and still more preferably 90 mass% or more, based on 100 mass% of the phosphorus-based flame retardant contained in the resin layer. This is because if the phosphorus flame retardant is within this range, the above flame retardant adhesive layer effects 1 and 2 can be more sufficiently exhibited.

The method of immersing a part of the adhesive layer in the surface of the fibrous base material is one of preferable embodiments of the synthetic leather of the present invention. This can improve both adhesiveness and flame retardancy. That is, the adhesive layer and the fiber base material can be favorably adhered to each other, and the peel strength of the synthetic leather can be improved. Further, since the voids in the base material in the region of the fiber base material into which the adhesive layer has penetrated are filled with the resin material, there is no oxygen contributing to combustion or a region having less oxygen contributing to combustion. Therefore, the burning speed of the burning from the surface of the synthetic leather can be decelerated upon reaching the area. In this case, if a large amount of flame retardant is contained in the adhesive layer, it is possible to provide synthetic leather having further improved flame retardancy and less possibility of expanding the flame.

Here, the fact that a part of the adhesive layer is immersed in the fiber base material means a state in which the resin material constituting the adhesive layer enters between fibers constituting the fiber base material and is cured.

In order to sufficiently enjoy the above effects, the impregnation rate of the resin material constituting the adhesive layer with respect to the thickness of the fiber base material is preferably 3% to 30%. By setting the content to 3% or more, the combustion speed can be remarkably reduced and the peel strength can be remarkably improved, and by setting the content to 30% or less, the flame retardancy and the peel strength can be obtained without impairing the texture of the fiber base material. The above-mentioned immersion rate was confirmed by the following method. That is, microscopic observation of a cross section of the synthetic leather in the thickness direction was carried out, and the thickness X of the fiber base material and the distance Y from the surface of the fiber base material on the adhesive layer side to the tip of the resin material impregnated into the fiber base material were actually measured at ten randomly selected positions. Then, the thickness X and the distance Y are respectively arithmetically averaged to calculate the average thickness X of the fiber base material_AVAnd average immersion depth Y_AV. Average depth of immersion Y_AVAverage thickness X relative to the fibrous substrate_AVThe ratio of (b) is the above-mentioned immersion rate.

As described above, the resin layer in the present invention may be a single layer or a multilayer, and in any of the embodiments, the resin material is mainly used and a flame retardant such as a phosphorus flame retardant is appropriately contained. The resin layer may contain one or more optional additives such as an ultraviolet absorber, an antioxidant, an antibacterial agent, an insect repellent, an odor preventive, an anti-coloring agent, a heat stabilizer, and an antistatic agent, within a range not departing from the gist of the present invention.

(fiber base)

The fiber base material is a base material that supports the resin layer.

In addition, the mass of the fiber base material is preferably 350g/m in view of heat generation characteristics²The following. If it is 350g/m²Hereinafter, the resin composition is not contained in a large amount in the resin layerThe phosphorus-based flame retardant can also impart desired flame retardant properties.

The thickness of the fiber base is not particularly limited, and is preferably 0.5mm to 1.2mm in consideration of chair stretch properties.

The density of the fiber base material is not particularly limited, but considering the chair stretch property, for example, in the case of a knitted fabric, the longitudinal density (wale) and the lateral density (course) are preferably 30 to 45, respectively. Here, the longitudinal density refers to the stitch (loop) connection in the longitudinal direction of the knitted fabric, and the lateral density refers to the stitch (loop) connection in the width direction of the knitted fabric.

The fiber base material is not particularly limited, and may be any material using fibers, such as a knitted fabric, a woven fabric, or a nonwoven fabric. Although not particularly limited, in consideration of chair stretch properties, a knitted fabric having an appropriate elongation is preferable as the fiber base material. The fibers forming the fibrous base material are not particularly limited, and examples thereof include synthetic fibers and natural fibers. Examples of the material of the synthetic fiber include, but are not limited to, polyester, polyamide, acrylic fiber, nylon, and the like. Examples of the material of the natural fiber include cotton, hemp, and rayon.

The fibers are preferably mainly polyester fibers in view of mechanical strength, stretchability, processability, cost, and the like. Further, if rayon is contained in a predetermined ratio, there are advantages in that the flame retardancy is improved and the smoke emission is suppressed. In addition, in the case of containing rayon, the blending ratio thereof is preferably polyester: rayon 25: 75-90: 10. if the ratio of rayon is large, the strength of the fiber base material tends to be reduced, and if the ratio of rayon is small, it is difficult to obtain a significant effect (effect of suppressing heat generation and smoke generation) of adding rayon.

The fibers constituting the fiber base material may include flame-retardant fibers represented by aramid fibers, polyphenylene sulfide fibers, and the like, or fibers subjected to flame-retardant treatment.

Further, flame retardant processing may be applied to a fabric formed into a knitted fabric, a woven fabric, a nonwoven fabric, or the like. The method of flame-retardant processing is not particularly limited, and examples thereof include a method in which a flame retardant is added to a dyeing solution used when dyeing a fiber base material, and the fiber base material is impregnated with the flame retardant together with the dyeing solution to impart flame retardancy (liquid stream flame-retardant method).

(production method)

The method for producing the synthetic leather of the present invention is not particularly limited. For example, in the case of forming a synthetic leather having the structure shown in fig. 4, a polycarbonate-based polyurethane resin solution for a skin layer is applied to a release paper or the like by a blade coater, a comma blade coater, or another common application means, and is dried by heating to obtain a skin layer (including a semi-cured state), and then a polycarbonate-based polyurethane resin solution for a foam layer is applied to an exposed surface of the obtained skin layer by the same application means as described above, and is dried by heating to foam the skin layer to form a foam layer (including a semi-cured state), and a polycarbonate-based polyurethane resin solution for an adhesive layer is applied to the exposed surface of the foam layer by the same application means as described above, and is dried by heating to form an adhesive layer. Synthetic leather can be obtained by laminating a fiber base material on the adhesive layer in a semi-cured state and then peeling off release paper or the like.

In the case of forming the synthetic leather having the structure shown in fig. 2, a skin-like layer is obtained in the same manner as described above, and then a fiber base material is laminated with an adhesive layer, and a release paper or the like is peeled off to obtain the synthetic leather. Alternatively, in the case of forming the synthetic leather having the structure shown in fig. 3, a skin-like layer is obtained in the same manner as described above, a fiber base material is laminated with a foam layer being bonded thereto, and a release paper or the like is peeled off to obtain the synthetic leather.

In addition, the surface of the skin layer may be embossed to give a leather-like appearance.

Further, an arbitrary layer such as a surface treatment layer (protective layer) may be formed on the skin-like layer of the synthetic leather obtained. A surface treatment layer is provided on the surface of the skin-like layer as necessary for the purpose of enhancing the surface gloss of the skin-like layer, improving the abrasion resistance, enhancing the touch feeling, and the like. For example, the surface treatment layer can be provided by applying a coating liquid in which a urethane resin, silicone, an organic filler, or the like is dispersed in an organic solvent or water to the surface of the skin layer.