Synthetic leather

Abstract

To provide a synthetic leather that is suitably used as a vehicle interior material or for furniture and has "moist and dry touch" like baby's cheek.SOLUTION: A synthetic leather is formed by disposing a synthetic resin layer and a fiber fabric base material in this order from a front surface side and has 3 to 15 μm of arithmetical average roughness, 200 to 700 μm of average length (RSm), and 0.1 or less of stick-slip coefficient. The stick-slip coefficient depends on dynamic friction coefficient measured according to JISK7125.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to synthetic leather, and more particularly to synthetic leather having excellent design.

[0002] Natural leather has been used for a long time as an intimate part of daily life, and has been used for various purposes as a tough material with moisture absorption, heat resistance, and cold resistance due to the properties of leather fabric. However, natural leather is limited in supply and has problems such as weakening and discoloration due to swelling, so synthetic leather is used as an alternative.

[0003] Consumer preferences are becoming more diverse, and there is a demand for synthetic leather with a better feel, one that is moist and smooth to the touch. As a method for improving the feel of synthetic leather, a technique for imparting a smooth feel by adding organic fine particles is known (Patent Document 1, etc.). However, a moist and smooth feel has not yet been achieved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-89245 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide synthetic leather that has a "moist and smooth feel" like the cheek of a newborn baby. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have invented a synthetic leather that has a moist and smooth feel.

[0007] The present invention relates to the following. (1) A synthetic leather comprising a synthetic resin layer and a fiber fabric base material in this order from the surface side, the synthetic leather having an arithmetic mean roughness (Ra) of 3 to 15 μm, a mean length (RSm) of 200 to 700 μm, and a stick-slip coefficient of 0.1 or less. Effect of the Invention

[0008] The present invention can provide synthetic leather that has a moist and smooth feel. Therefore, it can be suitably used for vehicle interior materials and furniture applications where a good tactile feel is required. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The synthetic leather of the present invention is characterized in that it comprises a synthetic resin layer and a fiber fabric substrate, and has an arithmetic mean roughness (Ra) of 3 to 12 μm, a mean length (RSm) of 200 to 700 μm, and a stick-slip coefficient of 0.1 or less. The stick-slip coefficient in the present invention is based on the dynamic friction coefficient measured in accordance with JIS K7125, and the specific measurement method is as follows. A test piece cut out from the synthetic leather of the present invention is attached horizontally to a measuring device. A weight (width: 62 mm, length: 102 mm, weight W: 9.8 N) wrapped around the test piece cut out from the synthetic leather of the present invention without slack is placed on the test piece attached to the measuring device, and slid at a speed of 50 mm / min with a load cell. The load at that time is measured, and the maximum point average load A and the minimum point average load B are read. The value calculated from the following formula is the stick-slip coefficient in the present invention. (Formula 1) Stick-slip coefficient = AB / W

[0010] Arithmetic mean roughness (Ra) is the average distance from the reference line to the unevenness of the surface, with the average value of the unevenness as a reference line. Arithmetic mean roughness (Ra) is measured based on JIS B0601:2013. The mean length (RSm) is a lateral parameter of the profile and is the average of the lengths of the profile elements in the reference length. The mean length (RSm) is measured according to JIS B0601:2013.

[0011] The synthetic leather of the present invention has a stick-slip coefficient of 0.1 or less. The stick-slip coefficient in the present invention is a value measured by the above-mentioned method, and a small stick-slip indicates 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, in other words, that the frictional vibration consisting of the stick behavior in which stress accumulates and the slip behavior until the stress is released and accumulated again is small and constant. Therefore, the surface of the synthetic leather of the present invention slides smoothly, and therefore, a synthetic leather having a moist and silky feel can be obtained.

[0012] The synthetic leather of the present invention has an arithmetic mean roughness (Ra) of 3 to 15 μm. The arithmetic mean roughness (Ra) is one of the parameters in the height direction of a profile curve, and is the average value of the height difference from the average plane in the profile curve over a reference length. The smaller the arithmetic mean roughness (Ra) value, the smaller the convex and concave portions in the surface shape. By having an arithmetic mean roughness (Ra) of 3 to 15 μm, the surface texture has a leather-like texture, while still providing a moist and smooth feel.

[0013] The synthetic leather of the present invention has an average length (RSm) of 200 to 700 μm. The smaller the average length (RSm), the narrower the width of the protrusions, which is an index showing that the surface shape tends to have narrower protrusions. By having an average length (RSm) of 200 to 700 μm, the surface grain has a leather-like texture, while still having a moist and smooth feel.

[0014] Methods for bringing the arithmetic mean roughness (Ra) and mean length (RSm) into the ranges specified in the present application include using a release paper that corresponds to the surface shape of the synthetic leather of the present invention, embossing the surface to correspond to the surface shape of the synthetic leather of the present invention, buffing the surface of the synthetic leather with sandpaper, and irradiating the surface with a laser.

[0015] The synthetic leather of the present invention is formed by providing, from the surface side, a synthetic resin layer and a fiber fabric substrate in this order.

[0016] The synthetic resin constituting the synthetic resin layer may be any resin that can be normally used in synthetic leather, but polyurethane resins and polyvinyl chloride resins are preferred.

[0017] Specific examples of the polyurethane resin include 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 a polycarbonate diol component with a non-yellowing diisocyanate component and a low molecular chain extender, etc. Furthermore, polyvinyl chloride resin, synthetic rubber, etc. may be mixed with the polyurethane resin as long as the physical properties required for synthetic leather are not impaired.

[0018] As the vinyl chloride resin, specifically, polyvinyl chloride, a copolymer of a vinyl chloride monomer with another monomer copolymerizable therewith, or a blend of these resins can be used. 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.

[0019] When the synthetic resin layer is made of polyvinyl chloride resin, a plasticizer is blended together with the polyvinyl chloride resin in order to more effectively exhibit flexibility similar to that of natural leather. Examples of the plasticizer include general phthalate ester 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 azelaate (DOZ); polymer plasticizers such as trioctyl trimellitate plasticizers and adipic acid polyester plasticizers such as polypropylene adipate; sebacic acid plasticizers; and phosphate ester plasticizers such as tricresyl phosphate (TCP), trixylenyl phosphate (TXP), tris(isopropylphenyl)phosphate, tributyl phosphate, triethyl phosphate, triphenyl phosphate, and triethylphenyl phosphate.

[0020] In addition to the above, the synthetic resin layer may contain various additives such as pigments, fillers, dispersants, antifoaming agents, matting agents, and lubricants.

[0021] The synthetic resin layer may be at least one layer, but is preferably two or more layers in consideration of mechanical strength, texture, etc. When the synthetic resin layer is formed of two layers, it consists of a layer located on the surface side of the synthetic leather (referred to as the "surface layer") and a layer in contact with the fiber fabric base material described below (referred to as the "adhesive layer").

[0022] The adhesive layer is a layer provided for bonding the surface layer and the fiber fabric substrate. The adhesive layer is preferably formed by impregnating a part of the composition constituting the adhesive layer into the fiber fabric substrate described below. The synthetic leather of the present invention has improved mechanical strength by impregnating a part of the composition constituting the adhesive layer into the fiber fabric substrate in the thickness direction of the synthetic leather.

[0023] A foam layer may be provided between the surface layer and the adhesive layer. By providing a foam layer, the touch and texture become better, and a synthetic leather with a more luxurious feel can be obtained. Methods for making the synthetic resin layer into a foam layer include physical foaming by mechanical stirring, chemical foaming by adding a foaming agent, and pseudo-foaming by adding hollow fine particles. The expansion ratio is preferably 1.3 to 2.0 times. When it is 1.3 to 2.0 times, the mechanical strength of the synthetic leather is ensured, and the feel and texture are good.

[0024] [Textile fabric base material] The fabric constituting the fiber fabric substrate is not particularly limited, and may be any fabric using fibers, such as knitted fabric, woven fabric, nonwoven fabric, etc. The fibers forming the fiber fabric substrate are not particularly limited, and may be synthetic fibers, natural fibers, etc. Examples of the synthetic fiber material include, but are not limited to, polyester, polyamide, acrylic, nylon, etc. Examples of the natural fiber material include, but are not limited to, cotton, linen, rayon, etc. The thickness of the fiber fabric substrate is not particularly limited, but considering the mechanical strength and texture of the synthetic leather, 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 basis weight of the fiber fabric substrate is also not particularly limited, but considering the mechanical strength and texture of the synthetic leather, as with the thickness, it is preferably 10 g / m 2 More than 500g / m 2 It is preferable that the thickness is less than 100 g / m 2 More than 400g / m 2 It is more preferable that:

[0025] [Surface treatment layer] In the synthetic leather of the present invention, it is preferable to provide a surface treatment layer on the synthetic resin layer. The surface treatment layer is provided for the purpose of giving the synthetic leather a glossy / matte finish, imparting abrasion resistance, providing a good feel, imparting stain resistance, and the like.

[0026] The surface treatment layer is preferably made of a polyurethane resin as a main component, such as polyether polyurethane resin, polyester polyurethane resin, polycarbonate polyurethane resin, etc., which may be used alone or in combination of two or more. Among them, polycarbonate polyurethane resin is preferred from the viewpoints of durability and weather resistance. If necessary, a crosslinking agent, an organic filler, an inorganic filler, etc. may be contained. The thickness of the surface treatment layer is not particularly limited, and is, for example, preferably from 1 to 40 μm, and more preferably from 3 to 30 μm. The surface treatment layer can be provided by coating the surface of the skin layer with a coating liquid prepared by dispersing the above composition in an organic solvent or water.

[0027] A primer layer may be provided between the surface treatment layer and the synthetic resin layer in order to improve adhesion between them. The surface treatment layer and the primer layer may contain additives such as pigments, antioxidants, ultraviolet absorbers, and catalysts.

[0028] The synthetic leather of the present invention has been described above. The synthetic leather of the present invention can be used for various purposes, but is particularly suitable for use as interior materials for vehicles and furniture, which require a good feel. EXAMPLES

[0029] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples, and various applications are possible within the scope of the technical concept of the present invention.

[0030] The stick-slip coefficient, arithmetic mean roughness (Ra), and mean length (RSm) in each of the examples and comparative examples were measured as follows. [Stick-slip coefficient] Using a measuring device (Universal testing machine manufactured by A&D Co., Ltd., model number: RTF-1310), a test piece cut out from synthetic leather is attached horizontally. A weight (width: 62 mm, length: 102 mm, weight W: 9.8 N) made by wrapping a test piece cut out from synthetic leather without slack is placed on the test piece attached to the measuring device, and the weight is slid at a speed of 50 mm / min using a load cell, and the load at that time is measured. The average load A at the maximum point and the average load B at the minimum point are read and calculated using the following formula. (Equation 2) Stick-slip coefficient = AB / W The synthetic leather was measured five times in each of the length and width directions, and the average value was taken as the stick-slip coefficient. [Arithmetic mean roughness (Ra)] The arithmetic mean roughness (Ra) was measured in accordance with JIS B0601:2013 using a surface roughness measuring instrument (manufactured by Mitutoyo Corporation, product name: SJ-4000). The measurement conditions were a scanning distance of 12.5 mm and a scanning speed of 0.5 mm / s. [Average length (Rsm)] The average length (RSm) was measured using a surface roughness measuring instrument (manufactured by Mitutoyo Corporation, product name: Sueftest SJ-400) in accordance with JIS B0601:2013. The measurement conditions were a scanning distance of 12.5 mm and a scanning speed of 0.5 mm / s.

[0031] Example 1 A vinyl chloride paste for the surface layer containing pigment and plasticizer (vinyl chloride made by Kaneka Corporation, product name: PSH24) was applied to a release paper with an arithmetic mean roughness (Ra) of 17.8 μm in the length direction and 15.3 μm in the width direction, and an average length (RSm) of 291 μm in the length direction and 287 μm in the width direction, to a dry thickness of 200 μm, and heated at a temperature of 180°C for 2 minutes to gel (resinify), forming a surface layer. Next, a vinyl chloride paste containing a foaming agent and a plasticizer (vinyl chloride product name: PQHPN, manufactured by Shin-Daiichi Vinyl Co., Ltd.) was applied to a dry thickness of 200 μm and heated at a temperature of 200° C. for 2 minutes to cause gelation (resinification) and foaming, forming a foam layer. Next, a vinyl chloride paste containing a plasticizer for the adhesive layer (vinyl chloride manufactured by Shin-Daiichi Vinyl Co., Ltd., product name: PQHPN) was applied at a rate of 100 g / m 2 Immediately after application, a knitted fabric was attached and heated at 180°C for 2 minutes to cause gelation (resinification), after which the release paper was peeled off to obtain synthetic leather. A resin composition for the surface treatment layer (solid concentration 20%) consisting of a polycarbonate-based polyurethane resin and a carbodiimide crosslinking agent was applied onto the obtained synthetic leather using a gravure roll, heated at 130°C in a continuous oven, and then aged at 50°C for 48 hours to obtain synthetic leather with a surface treatment layer having a coating thickness of 10 μm. The synthetic leather thus obtained had an arithmetic mean roughness (Ra) of 8.0 μm in the length direction and 9.0 μm in the width direction, an average length (RSm) of 378 μm in the length direction and 358 μm in the width direction, and a stick-slip coefficient of 0.003.

[0032] Comparative Example 1 A synthetic leather was obtained in the same manner as in Example 1, except that the release paper was changed to one with an arithmetic mean roughness (Ra) of 23.4 μm in the length direction and 19.4 μm in the width direction, and an average length (RSm) of 958 μm in the length direction and 742 μm in the width direction. The synthetic leather thus obtained had an arithmetic mean roughness (Ra) of 9.6 μm in the length direction and 10.9 μm in the width direction, an average length (RSm) of 974 μm in the length direction and 995 μm in the width direction, and a stick-slip coefficient of 0.3.

[0033] The synthetic leathers obtained in Example 1 and Comparative Example 1 were evaluated as follows. The evaluation results are shown in Table 1.

[0034] [Touch] Ten subjects ran their fingers over the resulting synthetic leather to judge whether it felt "moist and smooth to the touch" and evaluated the touch according to the following criteria. 〇: Seven or more subjects rated the product as "moist and smooth to the touch." ×: Six or fewer subjects rated the texture as "moist and smooth"

[0035] [Table 1]

[0036] From the results of the Examples and Comparative Examples, it is apparent that the synthetic leather of the present invention has a moist and smooth feel.

Claims

[Claim 1] A synthetic leather having a synthetic resin layer and a fiber fabric base material provided in this order from the surface side, The arithmetic mean roughness (Ra) is 3 to 15 μm and the mean length (RSm) is 200 to 700 μm; A synthetic leather having a stick-slip coefficient of 0.1 or less.

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