Synthetic leather

Abstract

To provide a dark-colored synthetic leather having mat feeling, and especially to provide a jet-black synthetic leather having deep mat feeling, and also to provide a synthetic leather hardly causing window reflection when being used as a skin material of a vehicle interior item.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 40 or less of L*value in Lab color system, 3 to 15 μm of arithmetical average roughness, 200 to 700 μm of average length (RSm), and 1.0 or less of 60° gloss value.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 dark color and a matte texture that gives a more luxurious feel. Synthetic leather is used as a skin material to give a luxurious feel to interior items installed in automobiles, but window reflections occur in which the interior items are reflected on the windshield, door glass, etc. In particular, window reflections occur on the windshield of dashboards and instrument panels, reducing the driver's visibility, so there is a demand for skin materials with a deep matte finish that are less reflective. A method for making synthetic leather matte is known in which a matting agent such as inorganic particles or organic particles is contained in the top coat (Patent Document 1, etc.). However, it has been difficult to achieve a deep matte finish with reduced gloss. In addition, dashboards and instrument panels are exposed to high temperatures, which can easily cause the matte agent to denature, making it difficult to maintain the matte effect over the long term. There is also the problem that the matte agent in the top coat falls off, causing the matte finish to be lost. Artificial leather made by three-dimensionally intertwining ultrafine nylon or polyester fibers and then soaking them in polyurethane resin can relatively easily achieve a suede-like, matte appearance (Patent Document 2, etc.). However, because such artificial leather has brushed fibers on the surface, the color and texture appear to vary in parts depending on the flow of the hair, making it difficult to consistently achieve a matte appearance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-279843 [Patent Document 2] JP 2012-117167 A Summary of the Invention [Problem to be solved by the invention]

[0005] To provide synthetic leather having a dark color and a matte feel, particularly a jet black tone and a deep matte feel, and also to provide synthetic leather which is less likely to show reflections on windows when used as a skin material for vehicle interior parts. [Means for solving the problem]

[0006] The present inventors conducted extensive research to solve the above problems and have developed the synthetic leather of the present invention.

[0007] The present invention relates to the following. (1) Synthetic leather having a synthetic resin layer and a fiber fabric base material in this order from the surface side, and having a color of L in the Lab color system. * The synthetic leather has a surface roughness value of 40 or less, an arithmetic mean roughness (Ra) of 3 to 15 μm, a mean length (RSm) of 200 to 700 μm, and a 60° gloss value of 1.0 or less. Effect of the Invention

[0008] The present invention can provide synthetic leather that is dark in color and has a matte finish. It is also possible to achieve a deep matte finish with a jet black tone. Therefore, it can be suitably used as an interior material for vehicles that require high design quality and a luxurious feel. In addition, it is suitable as a covering material for dashboards and instrument panels because it can suppress window reflections. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The synthetic leather of the present invention is L in the Lab color system. * The values, arithmetic mean roughness (Ra), mean length (RSm), and 60° gloss value are defined as follows: L in the Lab color system * The value is an index representing brightness and is measured in accordance with JIS Z 8781-4:2013. The 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. The 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. The 60° gloss value is an index representing the gloss level, and is measured in accordance with JIS Z 8741:1997. In this specification, the term "jet black" refers to a deep, dark black color.

[0010] The synthetic leather of the present invention is L in the Lab color system. * The specular gloss value is 40 or less, and the 60° gloss value is 1.0 or less. L in the Lab color system * When the value is 40 or less, the synthetic leather of the present invention exhibits a black color or a dark color close to black. When the 60° gloss value is 1.0 or less, the synthetic leather of the present invention has an excellent matte effect and provides a good matte feel. The above L * By combining both the 60° gloss value and the 60° gloss value, the surface of the synthetic leather has a calm dark color and a matte feel. Therefore, the synthetic leather of the present invention has a luxurious feel, and when used as a skin material for the instrument panel of an automobile, light incident from the windshield or door glass is not reflected off the dashboard or instrument panel and is not reflected in the windows, providing a high-quality interior space.

[0011] From the perspective of creating a more luxurious feel and approaching jet black, * A value of less than 25 is preferred. In order to minimize the gloss and improve the matte finish, the 60° gloss value is preferably 0.5 or less, and more preferably 0.4 or less. L * A value of less than 25 and a 60° gloss value of 0.5 or less results in a synthetic leather that has a deep matte finish while still maintaining a jet black tone, giving it a more luxurious feel.

[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 grain has a leather-like texture, while also combining a matte feel and a jet-black tone. The synthetic leather is required to have an arithmetic mean roughness (Ra) of 3 to 15 μm in both the length and width directions.

[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 convex portion, which is an index showing that the surface shape tends to have narrower convex portions. By having an average length (RSm) of 200 to 700 μm, the surface grain has a leather-like texture, while also having a matte feel and a jet black tone. The average length (RSm) is required to be 200 to 700 μm in both the length direction and width direction of the synthetic leather.

[0014] Methods for bringing the arithmetic mean roughness (Ra) and mean length (RSm) into the ranges specified in the present application include using release paper that corresponds to the surface shape of the synthetic leather of the present invention, shaping the surface with an embossing roll that corresponds to the surface shape of the synthetic leather of the present invention, buffing the surface of the synthetic leather with sandpaper, and irradiating 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 surface layer is made of synthetic leather L * Black and / or dark color pigments and other pigments are contained so that the value is 40 or less. When the synthetic resin layer consists of a single layer, the synthetic resin layer contains black and / or dark color pigments.

[0023] 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.

[0024] 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 the expansion ratio is 1.3 to 2.0 times, the mechanical strength of the synthetic leather is ensured, and the feel and texture are good.

[0025] [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:

[0026] [Surface treatment layer] The synthetic leather of the present invention may have a surface treatment layer provided on the synthetic resin layer. The surface treatment layer is provided for the purpose of imparting abrasion resistance, touch, antifouling, etc. The surface treatment layer can be provided by coating the surface of the skin layer with a coating liquid in which a polyurethane resin is dispersed in an organic solvent or water as a base material. In the present invention, the weight of the surface treatment layer is 10 g / m 2 If the basis weight of the surface treatment layer is too high, the roughness of the synthetic leather described above tends to decrease, and it may become difficult to obtain the matte feel desired in the present application.

[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 known additives such as pigments, antioxidants, ultraviolet absorbers, catalysts, inorganic fine particles such as silica, and organic fillers.

[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 an interior material for vehicles, which requires good design and a luxurious feel, and is particularly suitable as a covering material for dashboards and instrument panels, since it reduces window reflections. 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] L in each Example and Comparative Example * The surface roughness (Ra), average length (RSm), and 60° gloss value were measured as follows. [L * value〕 Using a color difference meter (Konica Minolta, Inc., spectrophotometer CM-2500d, light source: D65), the L * The values ​​were measured. [Surface roughness (Ra)] The surface roughness (Ra) was measured using a surface roughness measuring instrument (manufactured by Mitutoyo Corporation, product name: SJ-4000) 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. [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. [60° gloss value] Using a gloss meter (portable gloss meter PG-1 model, manufactured by Nippon Denshoku Industries Co., Ltd.), the incidence angle was set to 60° and the 60° gloss value was measured in accordance with JIS Z 8741:1997.

[0031] Example 1 A resin composition for forming a surface layer, which is 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 vinyl chloride paste (vinyl chloride manufactured by Kaneka Corporation, product name: PSH24) to a release paper having a surface 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, was applied to a release paper having a surface 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, so as to have a dry thickness of 200 μm, and was heated at a temperature of 180° C. for 2 minutes to cause gelation (resinification), thereby forming a jet-black 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 2Immediately 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. The obtained synthetic leather L * The value was 22.6, the surface roughness (Ra) was 9.0 μm in the length direction and 7.0 μm in the width direction, the average length (RSm) was 320 μm in the length direction and 556 μm in the width direction, and the 60° gloss value was 0.3.

[0032] Example 2 A synthetic leather was obtained in the same manner as in Example 1, except that 4.5 parts by mass of white pigment, 0.1 part by mass of black pigment, 4.8 parts by mass of blue pigment, 1.5 parts by mass of red pigment, and 0.3 parts by mass of yellow pigment were added to 100 parts by mass of vinyl chloride paste for the surface layer to form a deep blue surface layer. The obtained synthetic leather L * The value was 34.0, the surface roughness (Ra) was 9.3 μm in the length direction and 9.3 μm in the width direction, the average length (RSm) was 315 μm in the length direction and 383 μm in the width direction, and the 60° gloss value was 0.4.

[0033] 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 a surface 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 obtained synthetic leather L * The value was 26.3, the surface roughness (Ra) 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, and the 60° gloss value was 1.3.

[0034] The following evaluations were carried out on the synthetic leathers obtained in Examples 1 and 2 and Comparative Example 1. The evaluation results are shown in Table 1.

[0035] 〔exterior〕 The appearance of the resulting synthetic leather was observed and rated according to the following criteria. ◎: Jet black (L * value is less than 25) and has a matte finish 〇: Dark tone (L *value is between 25 and 40) and has a matte finish ×: Dark tone (L * value is between 25 and 40) but has no matte finish

[0036] [Reflection in the window] The obtained synthetic leather was placed horizontally, and a flat plate (500mm x 500mm) of 3.5mmt green glass for automobile windows (solar transmittance 60%, according to JIS R3106) was placed at an angle of 30° from the synthetic leather to simulate an automobile windshield. Next, a white plate was placed at a height of about 2m to simulate the sky outdoors, and a 500W solar simulator was irradiated to adjust the illuminance at the position of the synthetic leather to 6000 lux. The degree of reflection on the window was visually observed and evaluated according to the following criteria. ○: No window reflections observed ×: Reflections are observed, impairing visibility

[0037] [Table 1]

[0038] From the results of the Examples and Comparative Examples, it is clear that the synthetic leather of the present invention has a jet black tone and a matte finish. Therefore, it can be suitably used as an interior material for vehicles that require high design quality and a luxurious feel. In addition, since it can suppress reflections on windows, it is also suitable as a covering material for dashboards and instrument panels.

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, L in the Lab color system * The value is 40 or less, 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 60° gloss value of 1.0 or less.

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