Skin material

Abstract

The purpose of the present invention is to provide a skin material in which a good uneven shape is formed on the surface without quilting, and which has excellent cushioning properties.　The present invention provides a skin material in which a skin layer and a cushion layer containing a nonwoven fabric are laminated, wherein the skin material has an uneven structure of the surface of the skin layer, and the cushion layer has an average density of 70-130 kg / m3 on the skin layer side and has an average density of 30-55 kg / m3 on the side opposite to the skin layer.

Description

skin material

[0001] This invention relates to a skin material.

[0002] Generally, genuine leather or synthetic leather is used as the surface material for parts of automobiles such as steering wheels, seats, doors, instrument panels, assist grips, and grips. Examples of synthetic leather surface materials include those in which a surface material is bonded to the surface of a cushioning material made of resin. Such surface materials are required to have a luxurious appearance and enhanced tactile feel. For example, International Publication No. 2021 / 240793 discloses a surface material having irregularities on its surface and a quilting pattern corresponding to these irregularities.

[0003] However, quilting is very costly. Therefore, the present invention aims to provide a surface material that has a good uneven surface shape without the need for quilting and has excellent cushioning properties.

[0004] The inventors diligently conducted research to solve the above problems. As a result, they discovered that the above problems can be solved by constructing a surface material by laminating a surface layer having an uneven surface structure and a cushion layer containing a nonwoven fabric as a cushioning material, and by controlling the density of the cushion layer to predetermined values ​​in the region on the side of the surface layer and the region on the opposite side of the surface layer, and thus completed the present invention.

[0005] In other words, the present invention relates to a skin material comprising a skin layer and a cushion layer including a nonwoven fabric, wherein the skin material has an uneven surface structure on the surface of the skin layer, and the cushion layer has an average density of 70 to 130 kg / m³ on the side of the skin layer. ３ The average density on the side opposite the epidermal layer is 30 to 55 kg / m³. ３ It is a skin material.

[0006] Figure 1 is a schematic cross-sectional view showing a skin material according to one embodiment of the present invention.

[0007] One embodiment of the present invention is a skin material comprising a skin layer and a cushion layer including a nonwoven fabric, wherein the skin material has an uneven surface structure on the surface of the skin layer, and the cushion layer has an average density of 70 to 130 kg / m³ on the side of the skin layer. ３ The average density on the side opposite the epidermal layer is 30 to 55 kg / m³. ３ This is a surface material. According to the present invention, a surface material with excellent cushioning properties can be obtained by forming a good uneven surface shape on the surface without quilting.

[0008] Surface materials used in automotive interior components are required to have excellent cushioning properties as well as a superior appearance. For example, as described in International Publication No. 2021 / 240793, surface materials with a textured surface created by quilting at each recess are known, but quilting is costly. Polyurethane resin is widely used as a cushioning material because it is lightweight, easy to mass-produce, and inexpensive, but when attempting to create a textured surface by press molding polyurethane resin, the polyurethane resin may melt during press molding, impairing breathability. Furthermore, in recent years, there has been a movement to reduce the amount of polyurethane resin used from an environmental perspective.

[0009] In this embodiment of the surface material, the surface material includes at least a cushion layer and a surface layer, and has an uneven surface structure, with a nonwoven fabric used for the cushion layer. In the cushion layer, the average density on the side of the surface layer is 70 to 130 kg / m³. ３ The average density on the opposite side of the epidermal layer is 30-55 kg / m³. ３ This is controlled to maintain the shape of the uneven surface structure (uneven shape) of the skin material while simultaneously ensuring cushioning.

[0010] Embodiments of the present invention will be described below with reference to the drawings as appropriate. However, the present invention is not limited to the embodiments described below. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. Also, the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios. Furthermore, in this specification, "X to Y" indicating a range includes X and Y, and means "X or more and Y or less". Also, unless otherwise specified, operations and measurements of physical properties, etc., are performed under conditions of room temperature (20 to 25°C) / relative humidity 40 to 50% RH.

[0011] [Skin Material] Figure 1 is a schematic cross-sectional view of a skin material according to one embodiment of the present invention. The skin material 1 of this embodiment has a cushion layer 3, an adhesive layer 4, and a skin layer 5 in this order on one surface of a base material 2, and the surface of the skin layer 5 has an uneven structure 6. The cushion layer 3 has a predetermined average density in the thickness direction in a region 3a on the side of the skin layer 5 and a region 3b on the opposite side of the skin layer 5. Here, the region 3a on the side of the skin layer 5 refers to the region in the thickness direction of the cushion layer from the surface facing the skin layer (in this case, the interface with the adhesive layer) to a position that is half the distance from the surface on the opposite side of the skin layer (the position shown by the dashed line in Figure 1). The region 3b on the opposite side of the skin layer 5 refers to the region in the thickness direction of the cushion layer from the position that is half the thickness of the distance from the surface facing the skin layer to the surface on the opposite side of the skin layer to the surface on the opposite side of the skin layer.

[0012] The main components of the skin material described above will be explained below. However, the skin material of the present invention is not limited to the form shown in Figure 1.

[0013] (Epidermal layer) The epidermal layer is formed on the outermost surface of the epidermal material. In this specification, "outermost surface" refers to the side that the user directly touches.

[0014] The surface material of this embodiment has an uneven surface structure on the surface of the surface layer. Having an uneven surface structure can provide a high-quality appearance. The shape of the uneven structure is not particularly limited.

[0015] The height difference of the uneven structure is not particularly limited, but is, for example, 1 mm or more, preferably 1.5 mm or more, more preferably 2 mm or more, even more preferably 2.5 mm or more, and even more preferably 3 mm or more. Within the above range, an even better appearance and a more luxurious appearance can be obtained. The upper limit of the height difference of the uneven structure is not particularly limited, but is, for example, 10 mm or less, preferably 8 mm or less, even more preferably 5 mm or less, and even more preferably 4 mm or less. That is, in a preferred embodiment, the height difference of the uneven structure is 1 to 10 mm. Within the above range, the tactile feel is excellent. The height difference of the uneven structure can be determined by the method described in the following examples. The height difference of the uneven structure of the surface layer can be adjusted, for example, by selecting the uneven structure of the mold when producing the surface material by press molding to obtain the desired height difference, and by controlling conditions such as the surface temperature of each layer during press molding.

[0016] The average spacing of the protrusions in the surface uneven structure of the skin material is not particularly limited, but is, for example, 1 to 10 mm, preferably 3 to 8 mm. This range is preferable because it provides excellent appearance. The average spacing of the protrusions is the average value of the distance between adjacent protrusions (local peaks), and can be determined by observing the surface uneven structure using a 3D scanner, similar to the measurement of the height difference of the uneven structure described in the embodiments below.

[0017] The surface layer is not particularly limited, but it is preferable to include synthetic leather or genuine leather as the surface material. The effects of the present invention can be obtained even more significantly with this configuration. As genuine leather, for example, cowhide, horsehide, pigskin, etc. may be used. Note that the above genuine leather includes split leather.

[0018] While there are no particular limitations on the synthetic leather, materials such as polyurethane (PU) resin, polyvinyl chloride (PVC) resin, and olefin-based thermoplastic elastomer (TPO) can be used, but it is preferable that the synthetic leather contains polyurethane resin. While there are no particular limitations on the polyurethane resin, examples include polycarbonate polyurethane resin, polyester polyurethane resin, and polyether polyurethane resin, which can be used individually or in combination of two or more. Among these, polycarbonate polyurethane resin is preferred because of its excellent abrasion resistance and weather resistance.

[0019] Polycarbonate polyurethane resin is a polyurethane resin having a polycarbonate skeleton in its main chain, and is synthesized by a urethane reaction between a polycarbonate diol and a diisocyanate. The polycarbonate polyurethane resin may be either a non-crosslinked or crosslinked polycarbonate polyurethane resin. The polycarbonate diol is obtained, for example, by reacting at least one carbonate compound selected from the group consisting of alkylene carbonates, diaryl carbonates, and dialkyl carbonates with a diol and / or a polyether polyol. Examples of alkylene carbonates among the carbonate compounds include, but are not limited to, ethylene carbonate, 1,2-propylene carbonate, and 1,2-butylene carbonate. Examples of diaryl carbonates include, but are not limited to, diphenyl carbonate, phenyl naphthyl carbonate, dinaphthyl carbonate, 4-methyldiphenyl carbonate, 4-ethyldiphenyl carbonate, 4-propyldiphenyl carbonate, 4,4'-dimethyldiphenyl carbonate, 4,4'-diethyldiphenyl carbonate, and 4,4'-dipropyldiphenyl carbonate. Examples of dialkyl carbonates include, but are not limited to, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, di-n-butyl carbonate, diisobutyl carbonate, di-t-butyl carbonate, di-n-amyl carbonate, and diisoamyl carbonate. Examples of diols to be reacted with the above carbonate compounds include, but are not limited to, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-methylpentanediol, 3-methylpentanediol, 2,2,4-trimethyl-1,6-hexanediol, 2,3,5-trimethylpentanediol, and mixtures thereof.Examples of polyether polyols include, but are not limited to, polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, alkylene oxide adducts of diols, and mixtures thereof. Examples of the above diols include, but are not limited to, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, isomerized pentanediols, isomerized hexanediols, or octanediols (e.g., 2-ethyl-1,3-hexanediol, 1,2-bis(hydroxymethyl)-cyclohexanone, 1,3-bis(hydroxymethyl)-cyclohexanone, 1,4-bis(hydroxymethyl)-cyclohexanone), trimethylolpropane, and glycerin. Examples of alkylene oxides, though not limited to those listed below, include ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 2,3-butylene oxide, tetrahydrofuran, styrene oxide, and epichlorohydrin. The alkylene oxides may be used individually or in combination of two or more types. The diols and polyether polyols may also be used individually or in combination of two or more types. Examples of diisocyanates include, but are not limited to, aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate (HDI), alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate and isophorone diisocyanate (IPDI), and aromatic diisocyanates such as tolylene diisocyanate (TDI), xylylene diisocyanate, and 4,4'-diphenylmethane diisocyanate (MDI). The above reaction may be carried out in the presence of a chain extender such as 1,4-butanediol, 1,6-hexanediol, or ethylenediamine. The molecular weight (weight-average molecular weight) of the polycarbonate polyurethane resin is not particularly limited, but is preferably 15,000 to 150,000. The above polycarbonate polyurethane resin may be used alone or in the form of a mixture of two or more types.

[0020] Polyester polyurethane resin is a polyurethane resin having a polyester backbone in its main chain, and is synthesized by the reaction of a polyester polyol with a diisocyanate. The above reaction may be carried out in the presence of a chain extender. Examples of polyester polyols are, but are not limited to, those obtained by polycondensation of dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, and terephthalic acid with glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 1,8-octamethylenediol, neopentyl glycol, bishydroxymethylcyclohexane, bishydroxyethylbenzene, and alkyldialkanolamines. Furthermore, examples of diisocyanates include, but are not limited to, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, Examples include methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer isocyanate obtained by converting the carboxyl group of a dimer acid to an isocyanate group. The molecular weight (weight-average molecular weight) of the polyester polyurethane resin is not particularly limited, but is preferably 15,000 to 150,000. The above polyester polyurethane resin may be used alone or in the form of a mixture of two or more.

[0021] Polyether polyurethane resin is a polyurethane resin having a polyether backbone in its main chain, and is synthesized by the reaction of a polyether polyol with a diisocyanate. This reaction may be carried out in the presence of a chain extender. The polyether polyol is not particularly limited, but the same polyether polyols described in the section on polycarbonate polyurethane resin can be used. Examples of diisocyanates include, but are not limited to, hexamethylene diisocyanate, tolidine diisocyanate, isophorone diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 1,5-naphthalene diisocyanate, aliphatic diisocyanates, aromatic diisocyanates, etc. The above diisocyanates may be used alone or in combination of two or more. The molecular weight (weight-average molecular weight) of the polyether polyurethane resin is not particularly limited, but is preferably 15,000 to 150,000. The above polyether polyurethane resin may be used alone or in the form of a mixture of two or more.

[0022] Polyvinyl chloride resin is vinyl chloride (CH ２ This resin is primarily composed of constituent units derived from HCl (containing more than 50 mol% of these constituent units). Any polyvinyl chloride resin commonly used for surface materials can be used without particular restrictions. For example, a polyvinyl chloride resin with an average degree of polymerization of 600 to 2000, preferably 650 to 1800, can be suitably used. An average degree of polymerization of 600 or higher provides excellent abrasion resistance and flexural resistance, while an average degree of polymerization of 2000 or lower provides excellent moldability. The average degree of polymerization of the polyvinyl chloride resin refers to the average degree of polymerization measured in accordance with JIS K-6720-2 (1999): "Test Methods for Polyvinyl Chloride Resins".

[0023] The polyvinyl chloride resin may be a homopolymer of vinyl chloride or a copolymer of vinyl chloride and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate, olefins such as ethylene, propylene, and styrene, (meth)acrylate esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate, maleic acid diesters such as dibutyl maleate and diethyl maleate, fumaric acid diesters such as dibutyl fumarate and diethyl fumarate, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl halides such as vinylidene chloride and vinyl bromide, and vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. The above polyvinyl chloride resin may be used alone or in the form of a mixture of two or more kinds.

[0024] The presence of each resin can be confirmed, for example, by performing NMR measurements ( １ 1H-NMR measurement, １３ 13C-NMR measurement, etc.), infrared spectrum analysis, GC-MS analysis, and the like.

[0025] In addition to the above components, the skin material may contain other components. Here, the other components are not particularly limited, and known materials commonly used for leather materials can be used in the same manner. Specifically, pigments, crosslinking agents (curing agents) (e.g., isocyanate-based crosslinking agents, carbodiimide-based crosslinking agents), auxiliaries, tactile agents (e.g., silicone-based tactile agents), leveling agents, thickeners, ultraviolet absorbers, and the like can be mentioned. The above other components may each be used alone or in the form of a mixture of two or more kinds.

[0026] The material of the surface material may be a thermoplastic resin or other material having a softening point (softening temperature) and a melting point, or it may be a thermosetting resin or other material that does not have a softening point or a melting point. Alternatively, it may be a material that does not have a melting point, such as genuine leather. If the surface material has a softening point and / or a melting point, the values ​​of the softening point and / or melting point are not particularly limited. If the surface material has a softening point and / or a melting point, the softening point of the surface material is, for example, 50 to 180°C, preferably 60 to 150°C. The melting point of the surface material is not particularly limited, but is, for example, 130°C or higher, preferably 150°C or higher. If the softening point and / or melting point of the surface material is within the above range, it is easier to control the surface temperature of the surface material within an appropriate range when manufacturing the surface material by press molding, and the surface material of this embodiment can be obtained more easily.

[0027] For example, if the surface material is synthetic leather containing polyvinyl chloride resin or polyurethane resin, the softening temperature of polyvinyl chloride resin is 65 to 85°C, and its melting point is 170°C. Polyurethane resin is a thermosetting resin, so it has no softening point or melting point. Natural leather such as genuine leather also has no melting point. In the case of 100% polyester fiber fabric, which can be used as a fiber base material as described later, the softening temperature is 238 to 240°C, and its melting point is 255 to 260°C. In this specification, the melting point is defined as the temperature that gives the extreme value of the melting absorption curve measured using a differential scanning calorimeter at a heating rate of 20°C / min. The softening point (softening temperature) is defined as the temperature at which the polymer softens and begins to flow, measured using a micro-melting point measuring device (manufactured by Yanagimoto Seisakusho).

[0028] The surface material may be one that has been bonded to a base material (not shown). In this case, an adhesive layer (not shown) made of adhesive may be further provided between the surface material and the base material. The specific form of the base material is not particularly limited, but one similar to base material 2 described later can be used. The specific form of the adhesive layer is also not particularly limited, but one similar to adhesive layer 4 described later can be used.

[0029] The surface material is not particularly limited, but it is preferably perforated. This can provide breathability and thus can be suitably used as an air-conditioning seat. When it is perforated, the hole diameter and interval of the perforations are not particularly limited. For example, the hole diameter of the perforations is 0.5 to 2 mm, and the interval of the perforations is 2 to 10 mm. In a preferred embodiment, the surface material includes synthetic leather or genuine leather as the surface material, and the surface material is perforated. This can provide breathability and the effects of the present invention can be obtained more significantly.

[0030] The thickness of the surface layer in the surface material is not particularly limited, but for example, it is 0.1 to 2 mm. If it is 0.1 mm or more, the wear resistance of the obtained surface material can be improved. Also, if it is 2 mm or less, the texture of the obtained surface material can be made good.

[0031] (Adhesive layer) The above surface layer and the cushion layer described later may be directly laminated, or may be bonded via an adhesive layer 4\. By providing the adhesive layer, the adhesiveness between the surface layer and the cushion layer is improved, and the surface layer and the cushion layer are firmly fixed. Also, the strength of the surface material can be improved. The material constituting the adhesive layer is not particularly limited, but preferably includes a hot melt adhesive. Examples of the hot melt adhesive include vinyl acetate - ethylene copolymer-based hot melt adhesives, olefin-based hot melt adhesives, polyamide-based hot melt adhesives, ester-based hot melt adhesives, polyisobutylene-based hot melt adhesives, etc. The hot melt adhesive may be in the form of an adhesive sheet . The melting point of the hot melt adhesive is not particularly limited, but for example, it is 90 to 130 °C, preferably 100 to 120 °C. The thickness of the adhesive layer is not particularly limited, but for example, it is 0.1 to 1 mm.

[0032] (Cushion layer) The cushion layer includes a non-woven fabric as a cushion material. The non-woven fabric is not particularly limited, and examples include spunbond non-woven fabric; dry non-woven fabrics obtained by various bonding methods such as thermal bonding method, chemical bonding method, needle punching method, hydroentangling method, and stitch bonding method; wet non-woven fabrics obtained by various bonding methods such as thermal bonding method, chemical bonding method, and spunlace method; and the like can be used.

[0033] The material of the non-woven fabric is not particularly limited, and it may be mainly composed of natural fibers or mainly composed of synthetic fibers. Examples of synthetic fibers include thermoplastic resin fibers such as polyester fibers, polyamide fibers, and polyolefin fibers. Examples of polyester fibers include polyethylene terephthalate fibers, polybutylene terephthalate fibers, and polytrimethylene terephthalate fibers. Examples of polyamide fibers include nylon 6 fibers and nylon 66 fibers. Examples of polyolefin fibers include polyethylene fibers and polypropylene fibers. Among them, polyester fibers are preferred from the viewpoints of exhibiting thermoplasticity, having high strength, and excellent durability.

[0034] The non-woven fabric is not particularly limited, but in addition to the above natural fibers and synthetic fibers that are the main materials of the non-woven fabric, it is preferably included with binder fibers (heat-adhesive fibers). The heat-fusing component of the heat-adhesive fibers is not particularly limited, but it preferably has a melting point lower by 40°C or more than the polymer components of the above natural fibers and synthetic fibers. The melting point of the heat-fusing component of the binder fibers is, for example, 140 to 170°C. Examples of the polymer used as the heat-fusing component of the binder fibers include polyurethane-based elastomers, polyester-based elastomers, non-elastic polyester-based polymers and their copolymers, polyolefin-based polymers and their copolymers, polyvinyl alcohol-based polymers, low-melting-point polyesters, low-melting-point polyamides, and the like.

[0035] The above nonwoven fabric preferably includes a longitudinal nonwoven fabric. A longitudinal nonwoven fabric is a nonwoven fabric in which the fibers are arranged in the thickness direction. Here, "the fibers are arranged in the thickness direction" means that when (X) is the total number of fibers arranged parallel to the thickness direction of the nonwoven fabric (total number of fibers in the longitudinal direction) and (Y) is the total number of fibers arranged perpendicular to the thickness direction of the nonwoven fabric (total number of fibers in the transverse direction), X is greater than Y. Furthermore, the longitudinal / transverse ratio (X / Y ratio) of the fibers constituting the longitudinal nonwoven fabric is preferably 1.5 or more, and more preferably 2.0 to 8.0. The ratio of the total number of fibers in the longitudinal direction (X) to the total number of fibers in the transverse direction (Y) can be calculated by cutting a longitudinal nonwoven fabric in the thickness direction, observing under a microscope the number of fibers arranged parallel to the thickness direction (0° to 45°) and the number of fibers arranged perpendicular to the thickness direction (more than 45° and less than or equal to 90°) in the cross-section, and taking the ratio between them.

[0036] While conventionally known methods can be employed to obtain such a vertical nonwoven fabric, one example is a method in which short fibers and heat-adhesive short fibers are kneaded together, spun into a uniform web using a roller card, and then heat-treated using a known heat treatment machine while folding the web in an accordion shape, or while it is folded, to form heat-sealed bonding points. Since most of the fibers constituting the web are usually arranged in the planar direction of the web, by continuously folding and laminating them in an accordion shape, most of the fibers can be arranged in the thickness direction. More specifically, a vertical nonwoven fabric can be manufactured by folding it in a zigzag pattern using a strut machine (registered trademark, nonwoven fabric manufacturing apparatus described in European Patent Application Publication No. 0350627) or an air-lay machine (e.g., V21 / R-K12, V21 / K12, manufactured by Fehler), followed by compression and heat treatment. The fiber length of the short fibers used in the vertical nonwoven fabric is preferably in the range of 30 to 100 mm. Furthermore, the vertical nonwoven fabric may be an accordion structure or a fibrous structure obtained by repeatedly depositing short fibers in a strip-like shape. The short fibers constituting the vertical nonwoven fabric are not particularly limited, and the same natural fibers, synthetic fibers, etc. as described above can be used, but polyester fibers and polyolefin fibers are preferred, and polyester fibers are more preferred. The same heat-adhesive fibers (binder fibers) as described above can be used, but it is preferable to use synthetic fibers with a melting point 40°C or more lower than the short fibers.

[0037] Using vertically woven nonwoven fabric in the cushioning layer can improve the durability of the surface material. Furthermore, it can improve moldability and breathability.

[0038] The cushion layer may optionally contain known additives such as heat stabilizers, pigments, flame retardants, conductivity imparters, antistatic agents, moisture permeability enhancers, water repellents, oil repellents, water absorbers, moisture absorbers, deodorants, defoamers, pigment dispersants, hydrolysis inhibitors, crosslinking agents, and thickeners.

[0039] In a preferred embodiment, the cushion layer is substantially made of a nonwoven fabric. In a preferred embodiment, the cushion layer is substantially made of a longitudinal nonwoven fabric. "Substantially made of a nonwoven fabric (longitudinal nonwoven fabric)" means that the inclusion of impurities of about 2-3% by mass or less is permissible. In a preferred embodiment, the cushion layer does not contain polyurethane resin. This avoids the dissolution of polyurethane resin during press molding, which would impair breathability, thus making it possible to obtain a surface material with excellent breathability.

[0040] In this embodiment of the surface material, the average density on the surface layer side of the cushion layer is 70 to 130 kg / m³. ３ The average density on the opposite side of the epidermal layer is 30-55 kg / m³. ３ The average density on the side of the epidermal layer is 70 kg / m³. ３ If the density is less than 130 kg / m³, the function of adhering to the epidermal layer and maintaining the shape of the surface's uneven structure cannot be sufficiently obtained. Also, the average density on the side of the epidermal layer is 130 kg / m³. ３ If it exceeds this, it becomes more likely to bottom out. On the other hand, the average density on the opposite side of the epidermal layer is 30 kg / m³. ３ If it is less than 55 kg / m³, the tactile sensation decreases, and the average density on the opposite side of the epidermal layer is 55 kg / m³. ３ Beyond this point, the cushioning effect is compromised.

[0041] Preferably, the average density on the surface layer side of the cushion layer is 80 to 130 kg / m³. ３ This configuration can further improve moldability. Preferably, the average density of the cushion layer on the side opposite the surface layer is 30 to 45 kg / m³. ３ This configuration can further improve cushioning. In a preferred embodiment, the average density on the surface layer side of the cushion layer is 80 to 130 kg / m³. ３ Furthermore, the average density of the cushion layer on the opposite side of the epidermal layer is 30-45 kg / m³. ３This allows for a higher level of compatibility between moldability and cushioning. Here, it is preferable that the "side of the skin layer" and the "side opposite the skin layer" in the cushioning layer are not separate layers but are formed as a single integrated layer. The average density can be determined by the method described in the examples below. The average density of the "side of the skin layer" and the "side opposite the skin layer" in the cushioning layer can be controlled, for example, by controlling the surface temperature of the skin material side and the surface temperature of the cushioning material side of the laminate by preheating during press molding of the laminate of the skin material and the cushioning material.

[0042] In this embodiment of the surface material, it is preferable that the density of the cushion layer decreases continuously in the thickness direction as it moves away from the surface layer. This can make the effects of the present invention even more pronounced.

[0043] The thickness of the cushioning layer in the surface material is not particularly limited, but is, for example, 1 to 20 mm, preferably 2 to 10 mm, more preferably 3 to 9 mm, and even more preferably 4 to 8 mm. The effects of the present invention can be more significantly obtained within the above range.

[0044] (Base Material) The surface material of this embodiment may have a base material 2 on the side opposite to the surface layer of the cushion layer. The base material is not particularly limited, and resin film base materials such as polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various types of nylon, polyolefin resins such as polypropylene, and fibrous base materials can be used, but a fibrous base material is preferred. The fibrous base material is not particularly limited, and examples include fabrics such as knitted fabrics, woven fabrics, nonwoven fabrics, and natural leather. Fabrics may be coated or impregnated with conventionally known solvent-based or solvent-free (including water-based) polymer compounds (e.g., polyurethane resins and their copolymers, and polyvinyl chloride resins) and then dry-coagulated or wet-coagulated. Furthermore, the fabric may be treated with known pretreatment agents (e.g., penetrating agents, water repellents, flame retardants, ultraviolet absorbers, etc.). The fibrous base material may be colored with dyes or pigments. Furthermore, the surface of the fibrous base material may have nap by conventionally known napping treatment.

[0045] The types of fibers that make up the fibrous base material are not particularly limited, and conventionally known fibers such as natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be listed, and two or more of these may be combined.

[0046] The thickness of the substrate is not particularly limited, and conventionally known knowledge may be adopted as appropriate, but for example, it may be 0.1 to 10 mm.

[0047] The base material 2 and the cushion layer 3 may be directly laminated together, or they may be bonded together via an adhesive layer. The material constituting the adhesive layer is not particularly limited, but the same material as the adhesive layer 4 described above can be used.

[0048] The overall thickness of the skin material in this embodiment is not particularly limited, but is, for example, 1 to 20 mm, and preferably 1 to 10 mm.

[0049] (Method for manufacturing the surface material) The method for manufacturing the surface material in this embodiment is not particularly limited, but it is preferable to use a press molding method because it is highly productive and has excellent moldability. As an example, a method including the following steps may be used: (1) A step of laminating a surface material and a cushioning material including a nonwoven fabric to obtain a laminate; (2) A step of press molding the obtained laminate to obtain a surface material including a surface layer and a cushioning layer: Here, the mold used in press molding has an uneven structure on the surface that is in contact with the surface material. In this way, a cushioning layer having an uneven structure on its surface and where the average density on the side of the surface layer and the average density on the opposite side of the surface layer are both predetermined values ​​can be obtained at low cost. Therefore, a surface material with excellent cushioning properties can be easily obtained by forming a good uneven shape on the surface without quilting. In the surface material obtained in this way, the cushioning layer is integrally molded with the surface layer. In the cushioning layer, the "side of the surface layer" and the "side opposite the surface layer" are not separate layers, but are formed as a single unit. In the surface material obtained in this way, the density of the cushion layer decreases continuously in the thickness direction as it moves away from the surface layer.

[0050] The means of obtaining a laminate by laminating a surface material and a cushioning material including a nonwoven fabric are not particularly limited. The forms of the surface material and cushioning material are as described above. The density of the cushioning material before press molding is not particularly limited, but for example, 5 to 35 kg / m³ ３ The load is preferably 10 to 20 kg / m ３ The thickness of the cushioning material before press molding is not particularly limited, but is, for example, 5 to 50 mm, preferably 20 to 40 mm.

[0051] If the surface material further includes layers such as a base material and an adhesive layer in addition to the surface material and cushioning material, it is preferable to form a laminate that further includes these layers. For example, a laminate is made by laminating a base material, cushioning material, adhesive layer, and surface material in this order.

[0052] Press molding is performed by applying pressure to the laminate using a mold. The press molding method is not particularly limited, but cold press molding is preferred. Cold press molding is a technique in which the material is preheated and then pressed and molded with a mold. The mold consists of a mold 1 on the surface material side and a mold 2 on the cushion material side, and it is preferable that the mold 1 on the surface material side has an uneven surface structure on the side that is in contact with the surface material. The height difference and spacing of the uneven structure in mold 1 can be selected according to the desired height and spacing of the unevenness in the surface material.

[0053] In cold press molding, it is preferable to preheat the cushioning material and surface material in the laminate. The heating temperature can be set appropriately depending on the materials of the cushioning material and surface material. For example, if the surface material is a thermoplastic resin such as polyvinyl chloride resin, it is preferable to preheat the laminate so that the surface temperature on the surface material side is above the softening point and below the melting point of the surface material at the time of pressing. For example, if the surface material is a thermosetting resin such as polyurethane resin or genuine leather, it is more preferable that the surface temperature on the surface material side of the laminate at the time of pressing be 130 to 190°C, and even more preferable that be 140 to 180°C. It is preferable that the surface temperature at the time of pressing be within the above range because it is easy to control the average density on the surface material side of the cushioning layer in the resulting surface material to be within a predetermined range. The means for preheating and the preheating time are not particularly limited and can be set appropriately. In cold press molding, the temperature of both mold 1 and mold 2 at the time of pressing are room temperature (20 to 25°C).

[0054] When press-molding the laminate, it is preferable to preheat the surface temperature on the cushioning material side to a temperature below the melting point of the cushioning material. Preferably, the surface temperature on the cushioning material side of the laminate is below the melting point of the main fibers of the nonwoven fabric constituting the cushioning material, and above the melting point of the binder fibers. In one embodiment, preheating is performed so that the surface temperature on the cushioning material side of the laminate is, for example, 156 to 200°C, preferably 160 to 180°C. It is preferable that the surface temperature during pressing is within the above range because it is easy to control the average density on the side opposite the cushioning material of the resulting surface material to a predetermined range. The means for preheating and the preheating time are not particularly limited and can be set as appropriate.

[0055] The pressure during press molding is not particularly limited, but for example, it is between 0.2 and 10 MPa. Within this range, the effects of the present invention can be obtained even more significantly.

[0056] The press molding time is not particularly limited, but is, for example, 10 to 1000 seconds, preferably 20 to 300 seconds. Within this range, the effects of the present invention can be obtained even more significantly.

[0057] In the obtained skin material, the ratio of the height difference of the surface uneven structure to the height difference of the mold's uneven structure (height difference of the surface uneven structure of the skin material / height difference of the mold's uneven structure) is preferably 0.7 or more, more preferably 0.85 or more, even more preferably 0.9 or more, and most preferably 1.

[0058] Furthermore, if the laminate before press molding contains an adhesive layer, the adhesive layer may melt due to heating during press molding, resulting in the absence of an adhesive layer in the final surface material. In this case, the components of the adhesive layer, such as the adhesive, are dissolved into the surface layer and / or cushion layer. Such configurations are also included within the scope of the present invention.

[0059] (Applications) The surface material of the present invention has high cushioning properties and excellent appearance, so it can be used in a variety of products, including automotive interior parts, interior products such as sofas, shoes, and bags. In particular, the surface material of the present invention can be suitably used in automotive interior parts such as car seats. In particular, the surface material of this embodiment can be suitably used for car seats. It is especially suitable for the seat surface and the backrest of a car seat.

[0060] Furthermore, the following items are also included in the scope of the present invention: Item 1: A skin material comprising a skin layer and a cushion layer including a nonwoven fabric, wherein the skin material has an uneven surface structure, and the cushion layer has an average density of 70 to 130 kg / m³ on the side of the skin layer. ３ The average density on the side opposite the epidermal layer is 30 to 55 kg / m³. ３ The surface material is: item 2: the average density of the surface layer on the cushion layer side is 80 to 130 kg / m³ ３ The surface material as described in item 1; Item 3: The average density of the cushion layer on the side opposite to the surface layer is 30 to 45 kg / m³ ３ The surface material according to item 1 or 2; item 4: the surface material according to any one of items 1 to 3, wherein the height difference of the uneven structure is 3 mm or more; item 5: the surface material according to any one of items 1 to 4, wherein the surface layer includes synthetic leather or genuine leather which is a surface material, and the surface material is perforated. Item 6: A method for manufacturing a skin material, comprising the steps of: laminating a skin material and a cushioning material containing a nonwoven fabric to obtain a laminate; and press-molding the laminate to obtain a skin material containing a skin layer and a cushioning layer, wherein the mold used during press molding has an uneven surface on the side that contacts the skin material; Item 7: A method for manufacturing a skin material according to any one of Items 1 to 5, comprising the steps of: laminating a skin material and a cushioning material containing a nonwoven fabric to obtain a laminate; and press-molding the laminate to obtain a skin material containing a skin layer and a cushioning layer, wherein the mold used during press molding has an uneven surface on the side that contacts the skin material; Item 8: A skin material according to any one of Items 1 to 5, used in automotive interior parts.

[0061] The effects of the present invention will be explained using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. In the following examples, unless otherwise specified, the operations were carried out at room temperature (20 to 25°C). Also, unless otherwise specified, "%" and "parts" mean "mass percent" and "parts by mass," respectively.

[0062] [Example 1] The following materials were prepared: Surface material: Synthetic leather PU2.0 manufactured by Seiren Co., Ltd. (polyurethane resin, perforated with hole diameter 1.1 mm and pitch 5 mm, thickness 1 mm) Cushioning material: Vertical nonwoven fabric EBHJ400 manufactured by Teijin Frontier Co., Ltd. (main material: polyester fiber, binder fiber: low melting point polyester, melting point of binder fiber approximately 155°C, initial density 14 kg / m³) ３ (28mm thick) Adhesive sheet: Polyamide-based hot melt adhesive, basis weight 12g / m² ２ Melting point 110°C, thickness 0.1 mm. Mold: Sheet-shaped prototype mold (consisting of a lower mold on the side in contact with the surface material and an upper mold on the side in contact with the cushioning material, with identically shaped protrusions with a height of 3.5 mm repeatedly formed on the surface of the lower mold on the side in contact with the surface layer).

[0063] A laminate was created by stacking a cushioning material, an adhesive sheet, and a surface material in that order. A mold was placed on the surface material side and the cushioning material side, respectively, and press molding was performed. By preheating the laminate before press molding, the surface temperature of the laminate during press molding was set to 170°C on the surface material side and 160°C on the cushioning material side. The pressure during press molding was 5 MPa. The preheating time was 60 seconds, and the pressing time was 50 seconds. This obtained the surface material of this embodiment.

[0064] [Example 2] The surface material for this example was obtained in the same manner as in Example 1, except that the surface material was changed to genuine leather (perforated with holes 1.1 mm in diameter and 5 mm in pitch, 1 mm thick).

[0065] [Example 3] The surface material of this example was obtained in the same manner as in Example 1, except that the preheating time in press molding was changed to 50 seconds.

[0066] [Comparative Example 1] The surface material of this comparative example was obtained in the same manner as in Example 1, except that the surface temperature of the laminate during press molding was set to 170°C for both the surface material side and the cushioning material side.

[0067] [Comparative Example 2] The surface material of this comparative example was obtained in the same manner as in Example 1, except that the surface temperature of the laminate during press molding was set to 160°C for the surface material side and 160°C for the cushion material side.

[0068] [Evaluation] (Thickness of the surface material) The thickness of the surface material obtained in each example and comparative example was measured using calipers as the thickness of the part where the height of the protrusions of the uneven structure is maximum, and the average value was calculated to determine the thickness of the surface material.

[0069] (Average density of the cushion layer on the side of the epidermal layer and on the opposite side of the epidermal layer) The thickness of the cushion layer of the epidermal material obtained in each example and comparative example was measured with calipers. If the cushion layer had an uneven structure, the thickness of the part where the height of the protrusion was maximum was taken as the thickness of the cushion layer. Then, the average density of the region from the surface facing the epidermal layer to the point where the distance from the surface opposite the epidermal layer is half the thickness was calculated in the thickness direction of the cushion layer, and this was taken as the average density on the epidermal layer side. Here, the value of the average density was calculated from the thickness and weight of the region from the surface facing the epidermal layer to the point where the distance from the surface opposite the epidermal layer is half the thickness. Similarly, in the thickness direction of the cushion layer, the average density of the region from the point where the distance from the surface facing the epidermal layer is half the distance to the surface opposite the epidermal layer was calculated, and this was taken as the average density on the opposite side of the epidermal layer. Note that in the epidermal material of each example and comparative example, the contribution of components derived from the adhesive layer is relatively low in the measurement of the thickness and average density of the cushion layer, so the thickness of the adhesive layer can be ignored.

[0070] (Moldability of uneven structure) For the surface materials prepared in each example and comparative example, the height difference of the surface uneven structure was measured using a 3D scanner. The measurement results of the height difference of the surface uneven structure and the ratio of the height difference of the surface uneven structure to the height difference of the mold uneven structure are shown in Table 1 below. In Table 1 below, ○, △, and × follow the following criteria. If it is △ or ○, it can be used without problems: ○ (Good): 85% or more of the height difference of the mold uneven structure, △ (Acceptable): 70% or more but less than 85% of the height difference of the mold uneven structure, × (Unacceptable): Less than 70% of the height difference of the mold uneven structure.

[0071] (Cushioning) The cushioning properties of the surface materials prepared in each example and comparative example were evaluated. A compression testing machine was used as the apparatus. A spherical indenter (10 mm in diameter) was used as the indenter, and the load was 200 gf / cm. ２ The speed was set to 0.04 mm / sec. The displacement was measured when a load was applied from the side of the surface layer of the surface material. The results are shown in Table 1 below. Note that according to the following criteria, ○ or △ indicates that it can be used without problems: ○ (Good): Displacement of 1.8 mm or more, △ (Acceptable): Displacement of 1.2 mm or more but less than 1.8 mm, × (Not acceptable): Displacement of less than 1.2 mm.

[0072]

[0073] From the results in Table 1 above, it was found that the skin materials of Examples 1 to 3, in which a skin layer and a cushion layer containing a nonwoven fabric are laminated, and the cushion layer has a predetermined average density on both the side of the skin layer and the side opposite the skin layer, formed a good uneven surface and exhibited excellent moldability of the uneven structure. It was also found to have excellent cushioning properties. In contrast, the skin material of Comparative Example 2, in which the average density of the cushion layer on the side of the skin layer was less than the predetermined value, did not form a good uneven surface. Furthermore, the skin material of Comparative Example 1, in which the average density of the cushion layer on the side opposite the skin layer was greater than the predetermined value, exhibited insufficient cushioning.

[0074] This application is based on Japanese Patent Application No. 2024-156809, filed on 10 September 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0075] 1. Skin material, 2. Base material, 3. Cushion layer 3a. Region on the skin layer side, 3b. Region on the opposite side of the skin layer, 4. Adhesive layer, 5. Skin layer, 6. Uneven structure.

Claims

1. A skin material comprising a skin layer and a cushion layer containing a nonwoven fabric, wherein the skin material has an uneven surface structure on the surface of the skin layer, and the cushion layer has an average density of 70 to 130 kg / m³ on the side of the skin layer. ３ The average density on the side opposite the epidermal layer is 30 to 55 kg / m³. ３ It is a skin material.

2. The average density of the cushion layer on the surface layer side is 80 to 130 kg / m³. ３ The surface material according to claim 1.

3. The average density of the cushion layer on the side opposite to the surface layer is 30 to 45 kg / m³. ３ The surface material according to claim 1.

4. The surface material according to claim 1, wherein the height difference of the uneven structure is 3 mm or more.

5. The surface material according to claim 1, wherein the surface layer includes synthetic leather or genuine leather which is a surface material, and the surface material is perforated.

6. A method for manufacturing a skin material, comprising the steps of: laminating a skin material and a cushioning material including a nonwoven fabric to obtain a laminate; and press-molding the laminate to obtain a skin material including a skin layer and a cushioning layer, wherein the mold used during press molding has an uneven surface on the side that contacts the skin material.

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