Synthetic leather

Abstract

The present invention provides a novel synthetic leather which has a dry and comfortable surface. The synthetic leather according to the present invention is obtained by providing a synthetic resin layer and a fiber fabric base material in this order from the surface side, and has an arithmetic average roughness (Ra) of 3-15 [mu] m and an average length (RSm) of 200-700 [mu] m.

Description

Technical Field

[0001] The present invention relates to synthetic leather, and more particularly to synthetic leather having excellent texture, which has never been achieved before. Background Art

[0002] Natural leather has been used as a material closely related to daily life since ancient times. Due to the properties of leather fabric, it is used in various applications as a material with moisture absorption, heat resistance, cold resistance and toughness. However, natural leather has a limit in terms of supply, and has problems such as brittleness and discoloration due to swelling, so synthetic leather is used as a material to replace natural leather.

[0003] For example, Patent Document 1 proposes a technique of adding organic fine particles to impart a dry touch in order to provide a synthetic leather having an improved touch.

[0004] In addition, Patent Document 2 proposes a method of adding a matting agent such as inorganic particles or organic particles to a coating material in order to give a synthetic leather a matte color tone.

[0005] In addition, Patent Document 3 proposes artificial leather obtained by three-dimensionally entwining ultrafine nylon or polyester fibers and then impregnating them with a polyurethane resin in order to relatively easily express a suede-like, matte appearance.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2011-89245

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 10-279843

[0010] Patent Document 3: Japanese Patent Application Publication No. 2012-117167 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in order to present a good appearance imitating natural leather, a texture is usually provided on the surface of the synthetic leather.

[0013] However, it is difficult to give a dry touch to a synthetic leather provided with a texture, and the technology disclosed in Patent Document 1 is not sufficient. In addition, it is also difficult to provide a synthetic leather with a dry touch in the technologies disclosed in Patent Documents 2 and 3. In addition, the dry touch mentioned here refers to a long and smooth touch that can be felt when touching the surface with the hand. In addition, the texture refers to the three-dimensional concave and convex provided on the surface of the synthetic leather by processing in order to approximate the appearance of natural leather.

[0014] Therefore, an object of the present invention is to provide a synthetic leather having a dry touch on the surface and excellent texture which has not been achieved so far.

[0015] Means used to solve problems

[0016] The gist of the present invention is as follows.

[0017] (1) The synthetic leather of the present invention is formed by sequentially providing a synthetic resin layer and a fiber cloth substrate from the surface side, and is characterized in that an arithmetic mean roughness (Ra) is greater than or equal to 3 μm and less than or equal to 15 μm, and an average length (RSm) is greater than or equal to 200 μm and less than or equal to 700 μm.

[0018] (2) The synthetic leather according to (1) above, wherein the stick-slip coefficient is 0.1 or less.

[0019] (3) The synthetic leather described in (1) or (2) above, characterized in that the L* value is 40 or less and the 60° gloss value is 1.0 or less.

[0020] Effects of the Invention

[0021] The present invention can provide a synthetic leather which has a dry touch and has a good texture even when a texture is provided on the surface, which is a texture not previously available. DETAILED DESCRIPTION

[0022] [First embodiment]

[0023] The synthetic leather of the first embodiment is a synthetic leather in which a synthetic resin layer and a fiber cloth substrate are provided in order from the surface side, and has an arithmetic mean roughness (Ra) of 3 μm to 15 μm, and an average length (RSm) of 200 μm to 700 μm.

[0024] According to the synthetic leather having the above-mentioned structure, it is possible to provide a synthetic leather having a good texture which has never been seen before and which has a dry touch even when the surface is textured.

[0025] <Arithmetic mean roughness (Ra)>

[0026] The arithmetic mean roughness (Ra) in this embodiment is the average value of the distance from the reference line to the bottom of the concave part and the top of the convex part, with the average value of the height of the concave and convex parts of the surface as the reference line. Specifically, the arithmetic mean roughness (Ra) is measured based on JIS B 0601:2013.

[0027] The arithmetic mean roughness (Ra) of the synthetic leather of the present embodiment is greater than 3 μm and less than 15 μm, preferably greater than 5 μm and less than 13 μm, and more preferably greater than 7 μm and less than 11 μm. The arithmetic mean roughness (Ra) is one of the parameters in the height direction of the profile curve, and is the average value of the height difference from the average surface in the profile curve in the reference length. The smaller the value of the arithmetic mean roughness (Ra), the smaller the convex and concave parts of the surface shape become. By having an arithmetic mean roughness (Ra) in the range of greater than 3 μm and less than 15 μm, a synthetic leather with a dry touch can be provided even when it is processed to form an imitation leather by providing a texture on the surface.

[0028] The above-mentioned arithmetic mean roughness (Ra) is a parameter of the height direction of the profile curve, and is preferably 3 μm or more and 15 μm or less in either the length direction or the width direction of the synthetic leather. In addition, the length direction of the synthetic leather refers to the manufacturing direction of the synthetic leather, and the width direction of the synthetic leather refers to the direction perpendicular to the above-mentioned length direction.

[0029] <Average length (RSm)>

[0030] The average length (RSm) is a parameter of the profile curve in the lateral direction, and is the average length of the profile curve elements at the reference length. Specifically, the average length (RSm) is measured based on JIS B 0601:2013.

[0031] In the present invention, the profile curve refers to the concavo-convex shape measured in any one direction on the surface of the synthetic leather, and the lateral direction of the profile curve refers to the direction perpendicular to the height direction or depth direction of the concavo-convex shape observed on the profile curve.

[0032] The average length (RSm) of the synthetic leather of the present embodiment is more than 200 μm and less than 700 μm, preferably more than 250 μm and less than 650 μm, more preferably more than 300 μm and less than 600 μm. The smaller the value of the average length (RSm), the narrower the width of the convex portion becomes. The average length (RSm) is an index indicating the trend of the convex portion having a narrower width in the surface shape. By having an average length (RSm) of more than 200 μm and less than 700 μm, a synthetic leather having a surface texture that is imitation leather and presents a dry touch can be provided. The necessary condition for the average length (RSm) is that it is more than 200 μm and less than 700 μm in either the length direction and the width direction of the synthetic leather.

[0033] In addition, in the present embodiment, the method of setting the arithmetic mean roughness (Ra) and the average length (RSm) to the above-mentioned numerical range is not particularly limited. For example, as such method, there can be cited a method of using a release paper corresponding to the surface shape of the synthetic leather, a method of performing embossing processing such as shaping by an embossing roller in a manner corresponding to the surface shape of the synthetic leather, a method of polishing the surface of the synthetic leather using sandpaper, a method of irradiating the synthetic leather with a laser, etc.

[0034] <Layer structure of synthetic leather>

[0035] The synthetic leather of the present embodiment is constituted by sequentially providing a synthetic resin layer and a fiber cloth base material from the surface side.

[0036] [Synthetic resin layer]

[0037] Generally, any synthetic resin can be used as long as it can be used for synthetic leather, but polyurethane-based resins and polyvinyl chloride-based resins are preferred.

[0038] As the above-mentioned polyurethane resin, specifically, polyester polyurethane resin, polyether polyurethane resin, polycaprolactone polyurethane resin, polyester / polyether copolymer polyurethane resin, polyamino acid / polyurethane copolymer resin, non-yellowing polycarbonate polyurethane resin obtained by reacting polycarbonate diol component with non-yellowing diisocyanate component and low molecular weight chain extender, etc., can be listed. In addition, polyvinyl chloride resin, synthetic rubber, etc. can also be mixed in the above-mentioned polyurethane resin within the range of not damaging the various physical properties of synthetic leather. As the above-mentioned polyvinyl chloride resin, specifically, polyvinyl chloride, copolymers of other monomers copolymerizable with vinyl chloride monomer, or blends of these resins, etc. can be listed.

[0039] Examples of other monomers copolymerizable with the vinyl chloride monomer include ethylene, propylene, vinyl acetate, vinylidene chloride, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, maleic acid, and acrylonitrile fumarate.

[0040] When the synthetic resin layer is formed of a polyvinyl chloride resin, a plasticizer is blended with the polyvinyl chloride resin in order to more effectively exhibit softness similar to that of natural leather. Examples of the plasticizer include general phthalate plasticizers such as dioctyl phthalate (DOP), diisononyl phthalate (DINP), butyl benzyl phthalate (BBP), diisodecyl phthalate (DIDP), and diundecyl phthalate (DUP); general fatty acid ester plasticizers such as dioctyl adipate (DOA), dioctyl sebacate (DOS), and dioctyl azelate (DOZ); polymer plasticizers such as trioctyl trimellitate plasticizers and adipic acid polyester plasticizers such as polypropylene adipate; sebacic acid plasticizers; and phosphate plasticizers such as tricresyl phosphate (TCP), trixylene phosphate (TXP), triisopropylphenyl phosphate, tributyl phosphate, triethyl phosphate, triphenyl phosphate, and triethylphenyl phosphate. In addition to the above, the synthetic resin layer may contain various additives such as a pigment, a filler, a dispersant, a defoaming agent, a matting agent, and a lubricant.

[0041] The synthetic resin layer may be at least one layer, but preferably two or more layers are used in consideration of mechanical strength, hand feel, etc. When the synthetic resin layer is formed of two layers, it may be composed of a layer located on the surface side of the synthetic leather (sometimes referred to as a "skin layer" in the following description) and a layer in contact with the fiber cloth substrate described later (sometimes referred to as an "adhesive layer" in the following description).

[0042] The adhesive layer is a layer provided to bond the epidermis layer to the fiber cloth substrate. The adhesive layer is preferably formed by impregnating a portion of the composition constituting the adhesive layer into the fiber cloth substrate described later. The synthetic leather of this embodiment has a portion of the composition constituting the adhesive layer impregnated into the fiber cloth substrate in the thickness direction of the synthetic leather, thereby improving the mechanical strength of the synthetic leather. In the synthetic resin layer of this embodiment, a foaming layer may be further provided between the epidermis layer and the adhesive layer. By providing the foaming layer, the touch and feel become good, and a more high-grade synthetic leather can be obtained. As a method for providing a foaming layer in the synthetic resin layer, physical foaming based on mechanical stirring, chemical foaming based on the addition of a foaming agent, simulated foaming based on the addition of hollow particles, etc. can be cited.

[0043] The foaming ratio is preferably 1.3 to 2.0 times. When the foaming ratio is 1.3 to 2.0 times, the mechanical strength of the synthetic leather can be ensured while the touch and feel can be improved.

[0044] [Fiber fabric base material]

[0045] The fabric constituting the fiber cloth substrate is not particularly limited, and any fabric may be used as long as it is a fabric using fibers such as knitted fabric, woven fabric, and nonwoven fabric. The fibers constituting the fiber cloth substrate 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, and nylon. Examples of the material of the natural fiber include, but are not limited to, cotton, linen, and rayon.

[0046] The thickness of the fiber cloth substrate is not particularly limited. If the mechanical strength and feel of the synthetic leather are taken into consideration, the thickness is preferably 100 μm or more and 2000 μm or less, and more preferably 500 μm or more and 1200 μm or less. The weight per unit area of ​​the fiber cloth substrate is not particularly limited. If the mechanical strength and feel of the synthetic leather are taken into consideration in the same way as the thickness, the weight per unit area of ​​the fiber cloth substrate is preferably 10 g / m 2 Above and 500g / m 2 Below, more preferably 100g / m 2 Above and 400g / m 2 the following.

[0047] [Surface treatment layer]

[0048] The synthetic leather of this embodiment may be provided with a surface treatment layer on the synthetic resin layer.

[0049] The surface treatment layer is provided for the purpose of polishing or matting the synthetic leather, imparting abrasion resistance, imparting a tactile feel, imparting antifouling properties, and the like.

[0050] The surface treatment layer preferably has a polyurethane resin as the main agent, for example, polyether polyurethane resin, polyester polyurethane resin, polycarbonate polyurethane resin, etc., which can be used alone or in combination of two or more. Among them, from the viewpoint of durability and weather resistance, the main agent constituting the surface treatment layer is preferably a polycarbonate polyurethane resin. The surface treatment layer can be provided, for example, by applying a coating liquid having a polyurethane resin as the main agent and dispersed in an organic solvent or water to the surface of the epidermis.

[0051] The surface treatment layer may contain a crosslinking agent, an organic filler, an inorganic filler, etc. as necessary. The thickness of the surface treatment layer is not particularly limited, but is preferably 1 μm to 40 μm, and more preferably 3 μm to 30 μm.

[0052] The surface treatment layer can be provided by applying a coating liquid prepared by dispersing the above-mentioned composition in an organic solvent or water to the surface of the epidermis layer.

[0053] The surface treatment layer weight per unit area is not particularly limited, but is preferably 2 g / m2 Above and 50g / m 2 the following.

[0054] [Primer layer]

[0055] In the present embodiment in which the surface treatment layer is provided, a primer layer may be further provided between the surface treatment layer and the synthetic resin layer in order to improve the adhesion between the two.

[0056] In the surface treatment layer and / or primer layer, any one or two or more of a pigment, an antioxidant, an ultraviolet absorber, a catalyst, inorganic fine particles such as silica, or organic fine particles may be added.

[0057] The synthetic leather of the first embodiment has been described above. The present embodiment can be used as synthetic leather for various applications, and is preferably used for vehicle interior materials and furniture applications that require good tactile feel.

[0058] In addition, regarding the synthetic leather of this embodiment, the arithmetic mean roughness (Ra) and the average length (RSm) are measured from the outermost surface of the synthetic leather. Therefore, in the synthetic leather in which the synthetic resin layer is the outermost surface, the synthetic resin layer becomes the measurement surface, and in the case where the synthetic resin layer is also formed with a surface treatment layer, the surface treatment layer becomes the measurement surface.

[0059] The present invention provides a synthetic leather having excellent texture by adjusting both the arithmetic mean roughness (Ra) as a parameter in the height direction and the average length (RSm) as a parameter in the lateral direction of the concavo-convex shape on the outermost surface of the synthetic leather to predetermined preferred ranges.

[0060] [Second embodiment]

[0061] The synthetic leather of the second embodiment has the structure of the first embodiment described above, and further has the stick-slip coefficient adjusted to 0.1 or less. Therefore, in the following description, the stick-slip coefficient will be mainly described, and the description of the first embodiment will be appropriately referred to for other structures.

[0062] By having the above structure, it is possible to provide a synthetic leather having a wet touch in addition to a dry touch, such as a "wet and dry touch" like the cheek of a newborn baby. Therefore, the synthetic leather of the second embodiment is particularly preferably used for applications such as vehicle interior materials and furniture that require a good touch.

[0063] The stick-slip coefficient is a numerical value based on the dynamic friction coefficient. The dynamic friction coefficient is measured in accordance with JIS K7125. The specific measurement method is as follows.

[0064] A test piece I of a predetermined size cut from synthetic leather is horizontally mounted on the measuring device. In addition, a weight block (width: 62 mm, length: 102 mm, weight W: 9.8 N) without loose winding of a test piece II cut from the same synthetic leather is prepared. The weight block is placed on the test piece I mounted on the measuring device, and a force sensor is used to slide it at a speed of 50 mm / min. The load at this time is measured and the average load A at the maximum point and the average load B at the minimum point are read. The value calculated by the following formula is the stick-slip coefficient in the present invention.

[0065] (Equation 1) Stick-slip coefficient = (AB) / W

[0066] The stick-slip coefficient of the synthetic leather of the present embodiment is 0.1 or less.

[0067] The stick-slip coefficient in the present invention is a value measured by the above-mentioned method. A small stick-slip coefficient means that the difference between the maximum point average load A and the minimum point average load B in the measurement of the dynamic friction coefficient is small, that is, the friction vibration composed of the stick-slip behavior of accumulating stress and the slipping behavior until the stress is released and accumulated again is small and constant.

[0068] Therefore, when the surface of the synthetic leather of the present embodiment is touched by hand, the hand can slide smoothly on the surface of the synthetic leather, so that a synthetic leather having a moist and dry touch can be obtained.

[0069] [Third Embodiment]

[0070] Hereinafter, a third embodiment of the present invention will be described.

[0071] The synthetic leather of the third embodiment has an L* value of less than 40 and a 60° gloss value of less than 1.0 in addition to the structure of the first embodiment. Therefore, in the following description, the L* value and the 60° gloss value are mainly described, and the description of the first embodiment is appropriately referred to for other structures.

[0072] In addition, as mentioned above, consumers' intentions and uses for synthetic leather are becoming increasingly diverse. As one example, sometimes, as a synthetic leather with a more luxurious feel, a matte tone with a dark color and no gloss is required while having a dry touch on the surface. In addition, the matte tone mentioned here refers to a plain appearance with suppressed gloss on the surface.

[0073] More specifically, for example, synthetic leather is used as a surface material in order to give a sense of luxury to interior decorations installed in motor vehicles. In such applications, there is a problem of "window reflection" in which the reflection of the synthetic leather as an interior decoration is reflected on the windshield, door windows, etc. In particular, synthetic leather attached to the surface of the instrument panel or dashboard may produce window reflection on the windshield, resulting in reduced visual recognition for the driver. Therefore, synthetic leather with a deep matte color tone that is not easy to reflect is required.

[0074] In addition, recently, the number of vehicles using technology for displaying arbitrary information such as speed and map information on the windshield of the vehicle has increased. According to the above technology, the driver can confirm the necessary information while maintaining the forward posture. However, if "window reflection" of the reflected image of the synthetic leather as an interior product is reflected, it is sometimes difficult to confirm the information displayed on the above windshield. Based on such a fact, it is also required to suppress the occurrence of "window reflection".

[0075] Patent Document 2 discloses that a method of making a synthetic leather matte includes adding a matting agent such as inorganic particles or organic particles to a coating (Patent Document 1, etc.). However, it is difficult to produce a deep matte color with suppressed gloss.

[0076] Furthermore, since instrument panels and dashboards are exposed to high temperatures, the matting agent is easily denatured and it is difficult to achieve a matting effect for a long time. In addition, there is a problem that the matting agent in the paint falls off and does not show a matte color tone.

[0077] Patent Document 3 attempts to provide artificial leather with a suede-like and matte appearance. However, since the artificial leather has raised fibers on its surface, local differences in color tone or texture are observed depending on the flow of hair, making it difficult to stably present a matte appearance.

[0078] With respect to the above-mentioned conventional problems, the present embodiment having both the L* value and the 60° gloss value within the predetermined range can provide a synthetic leather having a dark color and a matte feel with excellent design properties in addition to a dry touch.

[0079] According to the present embodiment, a synthetic leather having a jet black tone and a deep matte feel can also be provided. Therefore, the synthetic leather of the present embodiment is particularly preferably used for interior materials of vehicles that require high design and a high-grade feel.

[0080] In addition, the synthetic leather of the present embodiment not only exhibits the above-described excellent designability, but also can well suppress light reflection. Therefore, when the synthetic leather of the present embodiment is used as the surface material of the instrument panel and dashboard, it can prevent the problem of "window reflection" caused by the reflection of light incident from the windshield and window glass on the instrument panel and dashboard. Thus, the synthetic leather of the present embodiment is excellent in terms of both designability and prevention of "window reflection", and therefore can provide a high-quality interior space when used as an interior material of a vehicle.

[0081] <L* value>

[0082] The L* value in the Lab colorimetric system is an index representing lightness and is a value measured in accordance with JIS Z 8781-4:2013.

[0083] When the L* value in the Lab colorimetric system is 40 or less, the synthetic leather of the present invention exhibits a dark color such as black or close to black. From the viewpoint of further creating a sense of luxury and approaching a jet-black tone, the L* value is more preferably less than 25. In addition, the "jet-black tone" means a deep and dark black.

[0084] In order to obtain the above L* value, it is only necessary to add a black and / or dark-colored pigment to the synthetic resin layer. In order to adjust the hue and the like, the synthetic resin layer may also contain pigments other than black and / or dark colors. In addition, when the synthetic resin layer is composed of one layer, it is preferable that the synthetic resin layer contains a black and / or dark-colored pigment. Further, when the synthetic resin layer has two or more layers, it is preferable that the skin layer contains a black and / or dark-colored pigment.

[0085] <60° gloss value>

[0086] The 60° gloss value is an index representing glossiness and is a value measured in accordance with JIS Z 8741:1997.

[0087] When the 60° gloss value is 1.0 or less, the synthetic leather of the present embodiment has an excellent light extinction effect and obtains a good matte feeling. In order to minimize the gloss as much as possible and improve the matte feeling, the 60° gloss value is more preferably 0.5 or less, and further preferably 0.4 or less.

[0088] According to the present embodiment in which the L* value is less than 25 and the 60° gloss value is 0.5 or less, it is possible to provide a synthetic leather having a jet-black tone, a deep matte feeling, and a stronger sense of luxury. Moreover, the synthetic leather has a dry touch, so it not only has good designability but also is skin-friendly.

[0089] In addition, regarding the synthetic leather of the third embodiment having a surface treatment layer, from the viewpoint of more effectively exhibiting the effects unique to the third embodiment, the unit area weight of the surface treatment layer is preferably 10 g / m2 By appropriately reducing the basis weight of the surface treatment layer, the roughness of the synthetic leather can be appropriately adjusted, and as a result, it is easy to provide a synthetic leather that exhibits a more excellent matte feel.

[0090] The embodiments of the synthetic leather of the present invention are described above, and the synthetic leather of the present invention at least has the structure of the first embodiment, and can further have the structure described in the second embodiment and / or the third embodiment. In addition, it can also have any structure within the scope of the purpose of the present invention.

[0091] [Example]

[0092] The present invention will be described in detail below based on examples. The present invention is not limited to these examples, and various applications are possible without departing from the technical concept of the present invention.

[0093] The arithmetic mean roughness (Ra) and mean length (RSm) in each example and comparative example, the stick-slip coefficient in Example 1 and Comparative Example 1, and the L* value and 60° gloss value in Example 2, Example 3 and Comparative Example 1 were measured as follows. In addition, in the above-mentioned measurements, the outermost surface side of the synthetic leather was the measurement object.

[0094] 〔Arithmetic mean roughness (Ra)〕

[0095] The arithmetic mean roughness (Ra) was measured using a surface roughness tester (manufactured by Mitutoyo Co., Ltd., trade name: SJ-4000) in accordance with JIS B0601: 2013. The measurement was performed in both the longitudinal direction and the width direction of the synthetic leather.

[0096] The measurement conditions were scanning distance: 12.5 mm, and scanning speed: 0.5 mm / s.

[0097] 〔Average length (RSm)〕

[0098] The average length (RSm) was measured using a surface roughness tester (manufactured by Mitutoyo Co., Ltd., trade name: Sueftest SJ-400) in accordance with JIS B 0601: 2013. The measurement was performed in both the longitudinal direction and the width direction of the synthetic leather.

[0099] The measurement conditions were scanning distance: 12.5 mm, and scanning speed: 0.5 mm / s.

[0100] 〔Stick-slip coefficient〕

[0101] Use a measuring device (product number: RTF-1310 manufactured by Universal Testing Instruments Co., Ltd. A&D) to horizontally mount the test piece cut from synthetic leather on the above measuring device. Wrap the test piece also cut from synthetic leather around a weight without looseness. Place the above weight (width: 62mm, length: 102mm, weight W: 9.8N) on the test piece mounted on the measuring device, and use a force sensor to slide it at a speed of 50mm / min to measure the load at this time. Read the average load A at the maximum point and the average load B at the minimum point from the measurement results, and calculate them using the following formula.

[0102] (Equation 2) Stick-slip coefficient = (AB) / W

[0103] Furthermore, the synthetic leather was measured five times in each of the longitudinal direction and the width direction, and the average value thereof was defined as the stick-slip coefficient.

[0104] 〔L* value〕

[0105] The L* value of the surface side of the synthetic leather was measured using a colorimeter (manufactured by Konica Minolta Co., Ltd., spectrophotometer CM-2500d, light source: D65) in accordance with JIS Z 8781-4:2013.

[0106] 〔60° gloss value〕

[0107] The 60° gloss value of the surface side of the synthetic leather was measured in accordance with JIS Z 8741:1997 at an incident angle of 60° using a gloss meter (product of Nippon Denshoku Industries, Ltd., portable gloss meter PG-1 model).

[0108] <Example 1>

[0109] On a release paper having an arithmetic mean roughness (Ra) of 17.8 μm in the length direction and 15.3 μm in the width direction and an average roughness (RSm) of 291 μm in the length direction and 287 μm in the width direction, a vinyl chloride slurry for a skin layer containing a pigment and a plasticizer (trade name of vinyl chloride manufactured by Kaneka Co., Ltd.: PSH24) is applied so as to have a dry thickness of 200 μm, and the skin layer is formed by heating at a temperature of 180°C for two minutes to gel (resinize).

[0110] Next, a vinyl chloride slurry containing a foaming agent and a plasticizer (vinyl chloride trade name: PQHPN manufactured by Shin Daiichi Vinyl Chloride Co., Ltd.) was applied on the skin layer to a dry thickness of 200 μm, and heated at 200° C. for two minutes to gel (resinize) and foam, thereby forming a foamed layer.

[0111] Next, the foam layer was coated with 100 g / m 2A vinyl chloride slurry containing a plasticizer for an adhesive layer (vinyl chloride product name: PQHPN manufactured by Shin Daiichi Vinyl Chloride Co., Ltd.) is applied in an amount, and then a knitted fabric is immediately laminated. After heating at a temperature of 180°C for two minutes to gel (resinize), the release paper is peeled off to obtain synthetic leather.

[0112] A resin composition (solid content concentration of 20%) for a surface treatment layer composed of a polycarbonate polyurethane resin and a carbodiimide cross-linking agent is applied to the obtained synthetic leather by a gravure roller, and after continuously heating at 130°C in an oven, it is matured at 50°C for 48 hours to obtain a synthetic leather having a surface treatment layer with a coating thickness of 10 μm.

[0113] The obtained synthetic leather had an arithmetic mean roughness (Ra) of 8.0 μm in the longitudinal direction and 9.0 μm in the width direction, an average length (RSm) of 378 μm in the longitudinal direction and 358 μm in the width direction, and a stick-slip coefficient of 0.003.

[0114] <Example 2>

[0115] Release paper having an arithmetic mean roughness (Ra) of 17.8 μm in the length direction and 15.3 μm in the width direction and an average roughness (RSm) of 291 μm in the length direction and 287 μm in the width direction was used. A resin composition for forming a skin layer was prepared by adding a plasticizer and a pigment (0.8 parts by mass of white pigment, 3.6 parts by mass of black pigment, 2.8 parts by mass of blue pigment, and 0.4 parts by mass of yellow pigment to 100 parts by mass of the vinyl chloride slurry) to the release paper. The resin composition for forming a skin layer was applied to the release paper in such a manner that the dry thickness was 200 μm, and the skin layer was gelled (resinified) by heating at a temperature of 180°C for two minutes to form a black skin layer with a jet black tone.

[0116] Next, a vinyl chloride slurry containing a foaming agent and a plasticizer (vinyl chloride trade name: PQHPN manufactured by Shin Daiichi Vinyl Chloride Co., Ltd.) was applied on the skin layer to a dry thickness of 200 μm, and heated at 200° C. for two minutes to gel (resinize) and foam, thereby forming a foamed layer.

[0117] Next, the foam layer was coated with 100 g / m 2 A vinyl chloride slurry containing a plasticizer for an adhesive layer (vinyl chloride product name: PQHPN manufactured by Shin Daiichi Vinyl Chloride Co., Ltd.) is applied in an amount, and then a knitted fabric is immediately laminated. After heating at a temperature of 180°C for two minutes to gel (resinize), the release paper is peeled off to obtain synthetic leather.

[0118] The obtained synthetic leather had an L* value of 22.6, an arithmetic mean roughness (Ra) of 9.0 μm in the longitudinal direction and 7.0 μm in the width direction, an average length (RSm) of 320 μm in the longitudinal direction and 556 μm in the width direction, and a 60° gloss value of 0.3.

[0119] <Example 3>

[0120] Synthetic leather was obtained in the same manner as in Example 2 except that 4.5 parts by mass of white pigment, 0.1 parts by mass of black pigment, 4.8 parts by mass of blue pigment and 0.3 parts by mass of yellow pigment were added to 100 parts by mass of vinyl chloride slurry for the surface layer to form a dark blue surface layer.

[0121] The obtained synthetic leather had an L* value of 34.0, an arithmetic mean roughness (Ra) of 9.3 μm in the length direction and 9.3 μm in the width direction, an average roughness (RSm) of 315 μm in the length direction and 383 μm in the width direction, and a 60° gloss value of 0.4.

[0122] <Comparative Example 1>

[0123] Synthetic leather was obtained in the same manner as in Example 1 except that the release paper was changed to one having an arithmetic mean roughness (Ra) of 23.4 μm in the longitudinal direction and 19.4 μm in the width direction and an average length (RSm) of 958 μm in the longitudinal direction and 742 μm in the width direction.

[0124] The arithmetic mean roughness (Ra) of the obtained synthetic leather was 9.6 μm in the length direction and 10.9 μm in the width direction, the average length (RSm) was 974 μm in the length direction and 995 μm in the width direction, the stick-slip coefficient was 0.3, the L* value was 26.3, and the 60° gloss value was 1.3. The following evaluation (touch 1) was performed on the synthetic leather obtained in Examples 1 to 3 and Comparative Example 1. The evaluation results are shown in Table 1.

[0125] [Touch 1]

[0126] Ten test subjects slid their fingers over the obtained synthetic leather to judge whether or not there was a "dry touch feeling". The touch feeling was evaluated based on the following criteria.

[0127] ○: 7 or more subjects rated it as "dry touch"

[0128] ×: The number of subjects who evaluated as “dry touch” was 6 or less The following evaluation (touch 2) was performed on the synthetic leathers obtained in Example 1 and Comparative Example 1. The evaluation results are shown in Table 1.

[0129] [Touch 2]

[0130] Ten test subjects slid their fingers over the obtained synthetic leather to judge whether or not there was a "wet and dry touch feeling". The touch feeling was evaluated based on the following criteria.

[0131] ○: 7 or more subjects rated it as "moist and dry touch"

[0132] ×: The number of subjects who evaluated as “wet and dry touch” was 6 or less The following evaluations (appearance, window reflection) were performed on the synthetic leathers obtained in Example 2, Example 3, and Comparative Example 1. Table 1 shows the evaluation results.

[0133] [Appearance]

[0134] The appearance of the obtained synthetic leather was observed and evaluated based on the following criteria.

[0135] ◎: It is a pitch-black tone (L* value less than 25) with a matte feel.

[0136] ○: Dark tone (L* value is 25 or more and 40 or less), with a matte feel

[0137] ×: Dark tone (L* value is 25 or more and 40 or less), but does not have a matte feel (window reflection)

[0138] The obtained synthetic leather substrate was placed horizontally with the lower surface side facing the lower surface, and a flat plate (500mm×500mm) of 3.5mm green glass for automobile windows (solar radiation transmittance 60%, based on JIS R 3106) was set at an angle of 30° from the synthetic leather to simulate the windshield of an automobile. Next, a white plate was set at a height of about 2m assuming the outdoor sky, and a 500W solar simulator was irradiated. The illuminance at the position of the synthetic leather was adjusted to 6000 lux, and the degree of window reflection was visually observed, and evaluated according to the following criteria.

[0139] 0: No window reflection observed

[0140] ×: Window reflection is observed, which impairs vision

[0141]

[0142] It was confirmed that all of Examples 1 to 3 satisfying the structure of the present invention had a dry touch.

[0143] In addition, Example 1 having a stick-slip coefficient of 0.1 or less has not only a dry touch but also a moist touch.

[0144] In addition, it was confirmed that Examples 2 and 3, which had an L* value of 40 or less and a 60° gloss value of 1.0 or less, had a jet black tone and a matte feel on the basis of a dry touch, and window reflection was suppressed. Therefore, Examples 2 and 3 can be preferably used as interior materials for vehicles requiring high design and a high-grade feel, and are also preferably used as surface materials for instrument panels and dashboards because they can suppress window reflection.

Claims

1. A synthetic leather comprising a synthetic resin layer and a fiber cloth substrate in this order from the surface side, characterized in that: The arithmetic mean roughness (Ra) is 3 μm or more and 15 μm or less, The average length (RSm) is 200 μm or more and 700 μm or less.

2. The synthetic leather according to claim 1, characterized in that The stick-slip coefficient is less than 0.

1.

3. The synthetic leather according to claim 1 or 2, characterized in that: L* value is below 40, The gloss value at 60° is less than 1.0.

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