Artificial leather and method for manufacturing the same

Abstract

Provided is an artificial leather comprising: a fibrous base material formed from superfine fibers having an average single fiber diameter of 0.1-10 µm; and a polymeric elastic body. The polymer elastic body comprises a compound having a hydrophilic group and a compound having an ethylene oxide skeleton. The content of the compound, having the ethylene oxide skeleton, in the polymeric elastic body of the artificial leather is 0.1-5 parts by mass per 100 parts by mass of the polymeric elastic body.　The present invention provides an artificial leather that achieves both a soft texture and excellent durability, and also provides a method for manufacturing the same.

Description

[Technical Field]

[0001] This invention relates to artificial leather that combines a flexible texture with excellent durability, and to a method for manufacturing the same. [Background technology]

[0002] Artificial leather, made from fibrous base materials such as nonwoven fabrics and polyurethane, possesses superior characteristics not found in natural leather, and its applications in clothing, upholstery, and automotive interior materials are expanding year by year. Regarding the polyurethane in artificial leather, methods using water-dispersible polyurethane, where polyurethane resin is dispersed in water, rather than organic solvent-based polyurethane, are being investigated from an environmental protection standpoint.

[0003] The solidification of water-dispersible polyurethane is mainly achieved through a so-called moist heat solidification method, which involves heating to break down the hydrated state of the polyurethane dispersion and cause the polyurethane emulsions to aggregate. However, in the moist heat solidification method, a phenomenon known as migration occurs, in which the polyurethane emulsion particles dispersed in water are pulled along by the movement of water and adhere concentratedly to the surface layer of the artificial leather. As a result, the adhesion between the fibrous substrate and the polyurethane becomes dense, and the intertwined parts of the fibers are strongly gripped, resulting in a hard texture.

[0004] To obtain a flexible artificial leather using water-dispersible polyurethane, a method has been proposed in which a thickening agent is added to the polyurethane dispersion to increase its viscosity, thereby suppressing the migration of the polyurethane emulsion to the surface layer of the artificial leather and obtaining a flexible texture (see Patent Documents 1-4). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2019 / 025964 [Patent Document 2] Japanese Patent Publication No. 2014-065980 [Patent Document 3] Japanese Patent Publication No. 2019-112742 [Patent Document 4] International Publication No. 2015 / 129602 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in methods using water-dispersible polyurethane, it is difficult to completely suppress migration phenomena, and the polyurethane is unevenly distributed on the surface layer of the artificial leather, resulting in less flexibility compared to methods using organic solvent-based polyurethane. Furthermore, the uneven distribution of polyurethane on the surface layer of the artificial leather increases its contact with moisture in the air, leading to hydrolysis of the polyurethane and a tendency for deterioration over time.

[0007] In the method disclosed in Patent Document 1, the adhesion between the fibers and polyurethane is reduced by impregnating the polyvinyl alcohol with an organic or inorganic salt simultaneously with the polyvinyl alcohol in the polyvinyl alcohol impregnation step before applying the water-dispersible polyurethane. However, because the polyurethane has a weak gripping force on the fibers, the abrasion resistance and durability are insufficient.

[0008] In the method disclosed in Patent Document 2, the solidification of polyurethane is accelerated by adding an ammonium salt. However, because the polyurethane contains an ammonium salt, the film properties of the polyurethane deteriorate, resulting in insufficient rebound compared to artificial leather using organic solvent-based polyurethane.

[0009] In the method disclosed in Patent Document 3, a thickening agent consisting of polysaccharides is applied to make the polyurethane porous. However, because the viscosity of the aqueous dispersion polyurethane formulation is low, the migration phenomenon cannot be said to be sufficiently suppressed, resulting in insufficient flexibility and durability.

[0010] In the method disclosed in Patent Document 4, polyurethane solidification in hot water results in insufficient abrasion resistance and durability because the polyurethane has a weak gripping force on the fibers.

[0011] Therefore, in view of the background of the above prior art, the present invention aims to provide an artificial leather that can not only manufacture environmentally friendly artificial leather but also achieve both a soft texture and excellent durability, as well as a method for manufacturing the same.

Means for Solving the Problems

[0012] That is, the present invention solves the above problems, and the artificial leather of the present invention is an artificial leather containing a fibrous substrate composed of ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymer elastomer, where the polymer elastomer includes a compound having a hydrophilic group and a compound having an ethylene oxide skeleton represented by the following general formula (1), and the content of the compound having an ethylene oxide skeleton in the polymer elastomer in the artificial leather is 0.1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymer elastomer.

[0013]

Chemical Formula

[0014] Here, R 1 and R 2 are functional groups having 1 to 20 carbon atoms, and n represents the number of repeating units of 10 to 200.

[0015] According to a preferred embodiment of the artificial leather of the present invention, R 1 in the general formula (1) is a functional group having an ester bond represented by the general formula (2).

[0016]

Chemical Formula

[0017] Here, R 3 is an alkyl group having 1 to 19 carbon atoms and an aryl group having 1 to 19 carbon atoms.

[0018] According to a preferred embodiment of the artificial leather of the present invention, the R of the general formula (2) is 3 This is a functional group that includes a terminal group selected from the group consisting of an isopropyl group, a tert-butyl group, and a mesityl group.

[0019] The present invention's method for manufacturing artificial leather is: A fibrous substrate made of ultrafine fiber-generating fibers or ultrafine fibers, After impregnating the polymer elastic precursor having hydrophilic groups with an aqueous dispersion containing a compound having an ethylene oxide skeleton represented by the general formula (1) in an amount of 0.1 parts by mass to 5 parts by mass per 100 parts by mass of solid content of the polymer elastic precursor, The aforementioned polymeric elastic precursor is solidified.

[0020] According to a preferred embodiment of the method for manufacturing artificial leather of the present invention, the viscosity of the aqueous dispersion is 1000 mPa·s or more and 10000 mPa·s or less. [Effects of the Invention]

[0021] According to the present invention, an artificial leather can be obtained that combines a flexible texture with excellent durability. [Modes for carrying out the invention]

[0022] The artificial leather of the present invention is an artificial leather comprising a fibrous base material consisting of ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastic body, wherein the polymeric elastic body comprises a compound having a hydrophilic group and a compound having an ethylene oxide skeleton represented by the following general formula (1), and the content of the compound having the ethylene oxide skeleton in the polymeric elastic body of the artificial leather is 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the polymeric elastic body.

[0023] [ka]

[0024] Here、R 2 This includes compounds with 1 to 20 carbon atoms, where n represents the number of repeating units between 10 and 200. R 1 This is a functional group having an ester bond represented by general formula (2). [ka] Here, R 3 These are alkyl groups having 1 to 19 carbon atoms and aryl groups having 1 to 19 carbon atoms.

[0025] The components will be described in detail below, but the present invention is not limited in any way to the scope described below, as long as it does not exceed the gist of the invention.

[0026] [Ultrafine fibers] Examples of resins that can be used in the ultrafine fibers used in the present invention include polyester resins and polyamide resins, from the viewpoint of excellent durability, particularly mechanical strength, heat resistance, and light resistance.

[0027] Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate. Polyester resins can be obtained, for example, from dicarboxylic acids and / or their ester-forming derivatives and diols.

[0028] Examples of dicarboxylic acids and / or ester-forming derivatives used in the aforementioned polyester resins include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and its ester-forming derivatives. In this invention, ester-forming derivatives refer to lower alkyl esters, acid anhydrides, acyl chlorides, etc. of dicarboxylic acids. Specifically, methyl esters, ethyl esters, hydroxyethyl esters, etc., are preferably used. A more preferred embodiment of the dicarboxylic acid and / or ester-forming derivative used in this invention is terephthalic acid and / or its dimethyl ester.

[0029] Examples of diols used in the aforementioned polyester resins include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and cyclohexanedimethanol. Among these, ethylene glycol is preferred.

[0030] When using polyamide resins as the resin for ultrafine fibers, polyamide 6, polyamide 66, polyamide 56, polyamide 610, polyamide 11, polyamide 12, copolymerized polyamides, etc., can be used.

[0031] Resins that can be used for ultrafine fibers may contain inorganic particles such as titanium dioxide particles, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storage agents, and antibacterial agents, depending on the purpose.

[0032] The cross-sectional shape of the ultrafine fibers can be either round or irregular. Specific examples of irregular cross-sections include elliptical, flattened, triangular, and other polygonal shapes, as well as sector and cross shapes.

[0033] In the present invention, it is important that the average single fiber diameter of the ultrafine fibers is 0.1 μm or more and 10 μm or less. By having an average single fiber diameter of 10 μm or less, preferably 7 μm or less, and more preferably 5 μm or less, the artificial leather can be made more flexible. Furthermore, the quality of the nap can be improved. On the other hand, by having an average single fiber diameter of 0.1 μm or more, preferably 0.3 μm or more, and more preferably 0.7 μm or more, the artificial leather can be made to have excellent color development after dyeing. Furthermore, when performing napping treatment by buffing, the ease of dispersing and separating the bundled ultrafine fibers can be improved.

[0034] In this invention, the average single fiber diameter is measured by the following method: (1) The obtained artificial leather is cut in the thickness direction and the cross-section is observed using a scanning electron microscope (SEM). (2) Measure the fiber diameters of any 50 ultra-fine fibers in the observation plane in three directions at the cross-section of each ultra-fine fiber. However, when adopting ultra-fine fibers with a special-shaped cross-section, first measure the cross-sectional area of the single fiber, and calculate the diameter of the circle corresponding to the cross-sectional area using the following formula. The diameter obtained from this is taken as the single-fiber diameter of the single fiber. Single-fiber diameter (μm) = (4 × (cross-sectional area of single fiber (μm 2 )) / π) 1 / 2 (3) Calculate the arithmetic mean value (μm) of the total 150 points obtained, and round it off to the second decimal place.

[0035] [Fiber-based substrate] The fiber-based substrate used in the present invention is composed of the above-mentioned ultra-fine fibers. Note that it is allowed that ultra-fine fibers of different raw materials are mixed in the fiber-based substrate.

[0036] As a specific form of the above-mentioned fiber-based substrate, a non-woven fabric formed by the entanglement of each of the above-mentioned ultra-fine fibers or a non-woven fabric formed by the entanglement of fiber bundles of ultra-fine fibers can be used. Among them, a non-woven fabric formed by the entanglement of fiber bundles of ultra-fine fibers is preferably used from the viewpoints of the strength and texture of artificial leather. From the viewpoints of flexibility and texture, particularly preferably, a non-woven fabric in which the ultra-fine fibers constituting the fiber bundles of ultra-fine fibers are appropriately spaced apart and have voids is preferably used. Thus, a non-woven fabric formed by the entanglement of fiber bundles of ultra-fine fibers can be obtained, for example, by expressing ultra-fine fibers after previously entangling ultra-fine fiber-expressing fibers. In addition, a non-woven fabric in which the ultra-fine fibers constituting the fiber bundles of ultra-fine fibers are appropriately spaced apart and have voids can be obtained, for example, by using sea-island composite fibers in which the space between island components can be made into voids by removing the sea component.

[0037] As the above-mentioned non-woven fabric, either a short-fiber non-woven fabric or a long-fiber non-woven fabric may be used, but a short-fiber non-woven fabric is more preferably used from the viewpoints of the texture and quality of artificial leather.

[0038] When using short-fiber nonwoven fabric, the fiber length of the short fibers is preferably in the range of 25 mm to 90 mm. By setting the fiber length to 25 mm or more, more preferably 35 mm or more, and even more preferably 40 mm or more, it becomes easier to obtain artificial leather with excellent abrasion resistance due to entanglement. Furthermore, by setting the fiber length to 90 mm or less, more preferably 80 mm or less, and even more preferably 70 mm or less, it is possible to obtain artificial leather with even better texture and quality.

[0039] In the present invention, when a nonwoven fabric is used as a fibrous base material, woven or knitted fabrics can be inserted into, laminated, or backed within the nonwoven fabric for purposes such as improving strength. The average single fiber diameter of the fibers constituting such woven or knitted fabrics is more preferably 0.3 μm to 10 μm, as this suppresses damage during needle punching and maintains strength.

[0040] The fibers that make up the aforementioned woven or knitted fabrics can include synthetic fibers such as polyesters like polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polylactic acid, as well as polyamides such as polyamide 6 and polyamide 66, regenerated fibers such as cellulose polymers, and natural fibers such as cotton and linen.

[0041] [Polymer elastic material] Next, the artificial leather of the present invention has a polymeric elastic body. This polymeric elastic body includes a "compound having hydrophilic groups" formed by the coagulation of a polymeric elastic body precursor having hydrophilic groups, as described later, and a compound having an ethylene oxide skeleton, as described later. Further details of this will be explained below.

[0042] (1) Polymer elastomer precursor First, the polymeric elastic precursor according to the present invention has hydrophilic groups. In the present invention, "having hydrophilic groups" means that the group itself "has a group having active hydrogen." Specific examples of such groups having active hydrogen include hydroxyl groups, carboxyl groups, sulfonic acid groups, amino groups, and the like.

[0043] Examples of polymeric elastic precursors include water-dispersible silicone resins, water-dispersible acrylic resins, water-dispersible polyurethane resins, and copolymers thereof. Among these, water-dispersible polyurethane resins are preferred in terms of texture. In particular, water-dispersible polyurethane resins prepared by reacting a polymeric polyol (described later), an organic diisocyanate, and a compound containing an active hydrogen component having a hydrophilic group to form a hydrophilic prepolymer, and then adding a chain extender and reacting them, are more preferably used. These will be explained in detail below.

[0044] (1-1) High molecular weight polyol Examples of polymeric polyols that are preferably used in the present invention include polyether-based polyols, polyester-based polyols, and polycarbonate-based polyols.

[0045] First, examples of polyether-based polyols include polyols obtained by addition-polymerization of monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and cyclohexylene using polyhydric alcohols or polyamines as initiators, as well as polyols obtained by ring-opening polymerization of the aforementioned monomers using protic acids, Lewis acids, and cationic catalysts as catalysts. Specifically, examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer polyols combining these.

[0046] Next, examples of polyester polyols include polyester polyols obtained by condensing various low molecular weight polyols with polybasic acids, and polyols obtained by opening polymerization of lactones.

[0047] Examples of low molecular weight polyols used in polyester polyols include one or more selected from linear alkylene glycols such as "ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol," branched alkylene glycols such as "neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-methyl-1,8-octanediol," alicyclic diols such as 1,4-cyclohexanediol, and aromatic dihydric alcohols such as 1,4-bis(β-hydroxyethoxy)benzene. Adducts obtained by adding various alkylene oxides to bisphenol A can also be used as low molecular weight polyols.

[0048] On the other hand, examples of polybasic acids used in polyester polyols include one or more selected from the group consisting of succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydroisophthalic acid.

[0049] Examples of polycarbonate-based polyols include compounds obtained by the reaction of a polyol with a dialkyl carbonate, or a polyol with a diaryl carbonate, or other polyols with carbonate compounds.

[0050] For polycarbonate-based polyols, low molecular weight polyols used in polyester-based polyols can be used. On the other hand, dimethyl carbonate and diethyl carbonate can be used as dialkyl carbonates, and diphenyl carbonate can be used as diaryl carbonates.

[0051] In this invention, the number-average molecular weight of the polymer polyol is preferably 500 or more and 5000 or less. By setting the number-average molecular weight of the polymer polyol to 500 or more, more preferably 1500 or more, it is possible to prevent the texture of the artificial leather from becoming hard. Furthermore, by setting the number-average molecular weight to 5000 or less, more preferably 4000 or less, it is possible to maintain the strength of the polyurethane as a binder.

[0052] (1-2) Organic diisocyanates The organic diisocyanates preferably used in the present invention include aromatic diisocyanates having 6 to 20 carbon atoms (excluding carbon atoms in the NCO group; the same applies hereinafter), aliphatic diisocyanates having 2 to 18 carbon atoms, alicyclic diisocyanates having 4 to 15 carbon atoms, aromatic aliphatic diisocyanates having 8 to 15 carbon atoms, modified forms of these diisocyanates (such as carbodiimide modified forms, urethane modified forms, uretdione modified forms, etc.), and mixtures of two or more of these.

[0053] Specific examples of aromatic diisocyanates having 6 to 20 carbon atoms include 1,3- and / or 1,4-phenylenediisocyanate, 2,4- and / 2,6-tolylenediisocyanate, 2,4'- and / or 4,4'-diphenylmethanediisocyanate (hereinafter abbreviated as MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, and 1,5-naphthylenediisocyanate.

[0054] Specific examples of aliphatic diisocyanates having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexaate.

[0055] Specific examples of the alicyclic diisocyanates having 4 to 15 carbon atoms include isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, and 2,5- and / or 2,6-norbornane diisocyanate.

[0056] Specific examples of aromatic aliphatic diisocyanates having 8 to 15 carbon atoms include m- and / or p-xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate.

[0057] Of these, preferred organic diisocyanates are alicyclic diisocyanates. Particularly preferred organic diisocyanates are dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI).

[0058] (1-3) Compounds containing active hydrogen components having hydrophilic groups Examples of hydrophilic active hydrogen component-containing compounds preferably used in the present invention include compounds containing a nonionic group and / or anionic group and / or cationic group and active hydrogen. These hydrophilic active hydrogen component-containing compounds can also be used in the form of salts neutralized with a neutralizing agent. By using these hydrophilic active hydrogen component-containing compounds, the stability of the aqueous dispersion used in the method for manufacturing artificial leather can be improved.

[0059] Examples of compounds having nonionic groups and active hydrogen include compounds containing two or more active hydrogen components or two or more isocyanate groups and having polyoxyethylene glycol groups with a molecular weight of 250 to 9000 in their side chains, as well as triols such as trimethylolpropane and trimethylolbutane.

[0060] Examples of compounds having anionic groups and active hydrogen include carboxyl group-containing compounds such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid, and their derivatives; compounds containing sulfonic acid groups such as 1,3-phenylenediamine-4,6-disulfonic acid and 3-(2,3-dihydroxypropoxy)-1-propanesulfonic acid, and their derivatives; and salts obtained by neutralizing these compounds with a neutralizing agent.

[0061] Examples of compounds having cationic groups and active hydrogen include tertiary amino group-containing compounds such as 3-dimethylaminopropanol, N-methyldiethanolamine, and N-propyldiethanolamine, as well as their derivatives.

[0062] (1-4) Chain elongators Preferably used chain extenders in the present invention include water, low molecular weight diols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol, alicyclic diols such as 1,4-bis(hydroxymethyl)cyclohexane, aromatic diols such as 1,4-bis(hydroxyethyl)benzene, aliphatic diamines such as ethylenediamine, alicyclic diamines such as isophoronediamine, aromatic diamines such as 4,4-diaminodiphenylmethane, aromatic aliphatic diamines such as xylenediamine, alkanolamines such as ethanolamine, hydrazine, dihydrazides such as adipic acid dihydrazide, and mixtures of two or more of these.

[0063] Among these, preferred chain elongators are water, low molecular weight diols, aromatic diamines, and aliphatic diamines, and more preferably water, ethylene glycol, 1,4-butanediol, 4,4'-diaminodiphenylmethane, ethylenediamine, and mixtures of two or more of these.

[0064] (1-5) Composition of water-dispersible polyurethane resin As described above, the water-dispersible polyurethane resin preferably used in the present invention is prepared by reacting the above-mentioned high-molecular-weight polyol, an organic diisocyanate, and a compound containing an active hydrogen component having a hydrophilic group to form a hydrophilic prepolymer, and then adding a chain extender and reacting it thereafter.

[0065] (1-6) Composition of polymeric elastic precursors From the viewpoint of hydrolysis resistance, the polymeric elastic precursor preferably contains polyetherdiol and / or polycarbonatediol as constituent components. By containing polyetherdiol as a constituent component, the polymeric elastic precursor can be made highly flexible due to the high degree of freedom of its ether bonds, resulting in a low glass transition temperature and weak cohesive force. On the other hand, by containing polycarbonatediol as a constituent component, the polymeric elastic can be made highly water-resistant, heat-resistant, weather-resistant, and mechanically superior due to the high cohesive force of its carbonate groups.

[0066] The number-average molecular weight of the polymer elastic precursor used in the present invention is preferably 20,000 to 500,000. A number-average molecular weight of 20,000 or more, more preferably 30,000 or more, can increase the strength of the polymer elastic material. On the other hand, a number-average molecular weight of 500,000 or less, more preferably 150,000 or less, can improve viscosity stability and workability.

[0067] The number-average molecular weight of the aforementioned polymeric elastic precursor can be determined by gel permeation chromatography (GPC) and measured under the following conditions. • Equipment: Tosoh Corporation "HLC-8220" • Column: "TSKgel α-M" manufactured by Tosoh Corporation • Solvent: N,N-dimethylformamide (DMF) ·Temperature: 40℃ • Calibration: Polystyrene.

[0068] (2) Compounds having an ethylene oxide skeleton In manufacturing the artificial leather of the present invention, it is important to add a compound having an ethylene oxide skeleton to the solution for forming the polymeric elastic body. In addition, if necessary, various stabilizers such as colorants (titanium dioxide, carbon black, etc.), ultraviolet absorbers (benzophenone-based, benzotriazole-based, etc.), antioxidants [hindered phenols such as 4,4-butylidene-bis(3-methyl-6-1-butylphenol); organic phosphates such as triphenyl phosphite and trichloroethyl phosphite, etc.], inorganic fillers (calcium carbonate, etc.), crosslinking agents (carbodiimide crosslinking agents and blocked isocyanate crosslinking agents), and thickeners (urethane-modified polyethers and acrylic polymers, etc.) can be included in the solution for forming the polymeric elastic body. Compounds having an ethylene oxide skeleton will be described in detail below.

[0069] The artificial leather of the present invention comprises a polymeric elastic material containing the aforementioned hydrophilic group compound and a compound having an ethylene oxide skeleton represented by the following general formula (1).

[0070] [ka]

[0071] Here, R 1 and R 2 This is a functional group having 1 to 20 carbon atoms, where n represents the number of repeating units between 10 and 200. In the process of manufacturing this artificial leather, a compound having an ethylene oxide skeleton represented by the general formula (1) is included in the solution for forming the polymeric elastic material.

[0072] R in this general formula (1) 1 Ya R 2Specific examples include alkyl groups having 1 to 20 carbon atoms, aryl groups having 1 to 20 carbon atoms, carbonyl groups having 1 to 20 carbon atoms, ether groups having 1 to 20 carbon atoms, carboxyl groups, functional groups having an ester bond to an alkyl group or aryl group having 1 to 20 carbon atoms, and functional groups having a peptide bond to an alkyl group or aryl group having 1 to 20 carbon atoms. Furthermore, in addition to linear chains, functional groups containing the above-mentioned functional groups as side chains may also be used for each functional group.

[0073] In particular, R in general formula (1) 1 It is preferable that the functional group has an ester bond represented by general formula (2).

[0074] [ka]

[0075] Here, R 3 These are alkyl groups having 1 to 19 carbon atoms and aryl groups having 1 to 19 carbon atoms. By using compounds having ester bonds, various side chains can be imparted to compounds having an ethylene oxide skeleton, thereby conferring properties suitable for the purpose.

[0076] In particular, in the present invention, R 3 It is preferable that the functional group includes a terminal group selected from the group consisting of isopropyl, tert-butyl, and mesityl groups. Having these functional groups increases the constraint on the molecular chain, which can contribute to improving the durability of the polymeric elastic material that grips the ultrafine fibers in artificial leather.

[0077] Furthermore, it is preferable that n in the above general formula (1) is between 10 and 200 repeating units. By setting n to 10 or more, more preferably 15 or more repeating units, moisture in the air can be selectively adsorbed, thereby suppressing the deterioration of the polymer elastomer that deteriorates over time in actual use. By setting n to 200 or less, more preferably 150 or less repeating units, compatibility with the polymer elastomer precursor can be improved, and inhibition of coagulation of the polymer elastomer can be suppressed.

[0078] The viscosity of the solution when a compound having an ethylene oxide skeleton is dissolved in water is preferably 500 mPa·s or more and 10,000 mPa·s or less. By setting the solution viscosity to 500 mPa·s or more, more preferably 1,000 mPa·s or more, the above-mentioned number of repeating units can be achieved, and the deterioration of the polymer elastomer that deteriorates over time in actual use can be suppressed. On the other hand, by setting the solution viscosity to 10,000 mPa·s or less, more preferably 9,000 mPa·s or less, the above-mentioned number of repeating units can be achieved, improving compatibility with the polymer elastomer precursor and suppressing inhibition of polymer elastomer coagulation.

[0079] The number-average molecular weight of the compound having an ethylene oxide skeleton added to the aqueous dispersion obtained by dispersing the polymer elastic material precursor in water is preferably 500 or more and 10,000 or less. By setting the number-average molecular weight to 500 or more, more preferably 800 or more, the number of repeating units described above can be achieved, and the deterioration of the polymer elastic material that deteriorates over time in actual use can be suppressed. On the other hand, by setting the number-average molecular weight to 10,000 or less, more preferably 9,000 or less, the number of repeating units described above can be achieved, improving compatibility with the polymer elastic material precursor and suppressing inhibition of coagulation of the polymer elastic material.

[0080] Furthermore, the number-average molecular weight of compounds having an ethylene oxide skeleton can be measured in the same way as the number-average molecular weight of the polymeric elastic precursors described above.

[0081] The content of the compound having an ethylene oxide skeleton added to the aqueous dispersion is preferably 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the solid content of the polymer elastic material precursor in the aqueous dispersion. By setting the content to 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 part by mass or more, it is possible to suppress the deterioration of the polymer elastic material that is uniformly present in the artificial leather and deteriorates over time during actual use. On the other hand, by setting the content to 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 2.5 parts by mass or less, the number of repeating units can be set as described above, improving compatibility with the polymer elastic material precursor and suppressing inhibition of coagulation of the polymer elastic material.

[0082] The viscosity of the aqueous dispersion containing the compound having an ethylene oxide skeleton is preferably 1,000 mPa·s or more and 10,000 mPa·s or less. A viscosity of 1,500 mPa·s or more, and more preferably 1,800 mPa·s or more, can suppress migration. On the other hand, by setting the viscosity to 10,000 mPa·s or less, and more preferably 9,000 mPa·s or less, the impregnation properties of polyurethane can be improved.

[0083] (3) Polymer elastic material The polymeric elastic material in the artificial leather of the present invention preferably contains polyetherdiol and / or polycarbonatediol as constituent components.

[0084] The polymeric elastic material according to the present invention, by containing polyetherdiol as a constituent component, can be made highly flexible due to its high degree of freedom in ether bonds, resulting in a low glass transition temperature and weak cohesive force. On the other hand, by containing polycarbonatediol as a constituent component, the polymeric elastic material can be made highly durable, such as water resistance, heat resistance, and weather resistance, due to the high cohesive force of its carbonate groups.

[0085] The polymeric elastic material used in the present invention appropriately grips the fibers together in the artificial leather, and preferably, from the viewpoint of having a pile on at least one side of the artificial leather, it is preferable that it exists inside the fibrous base material.

[0086] [Artificial leather] In the artificial leather of the present invention, it is important that the content of the compound having an ethylene oxide skeleton represented by general formula (1) in the polymer elastic body of the artificial leather is 0.1 parts by mass or more and 5 parts by mass or less. When the content in the polymer elastic body is 0.1 parts by mass or more, preferably 0.3 parts by mass or more, it is uniformly present in the artificial leather and the deterioration of the polymer elastic body that deteriorates over time in actual use can be suppressed. On the other hand, when the content in the polymer elastic body is 5 parts by mass or less, preferably 4 parts by mass or less, the compound having an ethylene oxide skeleton is present with good compatibility with the polymer elastic body precursor and the inhibition of coagulation of the polymer elastic body can be suppressed.

[0087] The artificial leather of the present invention preferably has a longitudinal bending length of 40 mm or more and 150 mm or less, as defined by the "41.5° cantilever method" described in JIS L1913:2010 "General Nonwoven Fabric Testing Method". By setting the bending length within the above range, it is possible to obtain an appropriate balance of flexibility and resilience. Regarding the bending length, it is preferably 50 mm or more, more preferably 55 mm or more, from the standpoint of obtaining a resilient artificial leather, and preferably 120 mm or less, more preferably 110 mm or less, from the standpoint of obtaining a flexible artificial leather.

[0088] In the artificial leather of this invention, the longitudinal direction refers to the direction in which the napping treatment is applied to the artificial leather. Methods for determining the napping direction can be appropriately employed depending on the composition of the artificial leather, such as visual inspection by tracing with a finger or SEM imaging. Specifically, the longitudinal direction is the direction in which the nap fibers can be made to lie flat or stand up when traced with a finger. Alternatively, by SEM imaging of the surface of the artificial leather traced with a finger, the direction in which the most flattened nap fibers are present is determined as the longitudinal direction. On the other hand, in the artificial leather of this invention, the transverse direction refers to the direction perpendicular to the longitudinal direction.

[0089] The artificial leather of the present invention preferably exhibits a wear loss of 30 mg or less after 50,000 cycles of the Martindale abrasion test specified in JIS L1096:2010 "Testing Methods for Woven and Knitted Fabrics" following an accelerated degradation test (jungle test, left for two weeks in a space at 70°C and 95% relative humidity) under high temperature and high humidity conditions. By keeping the wear loss after the accelerated degradation test (jungle test) within the above range, deterioration of the polymer elastic material can be suppressed even with long-term use, and the appearance of the artificial leather can be maintained. From the viewpoint of suppressing deterioration of the appearance of the artificial leather, the wear loss is preferably 25 mg or less, and more preferably 20 mg or less.

[0090] [Manufacturing method for artificial leather] The present invention provides a method for producing artificial leather, in which an ultrafine fiber-generating fiber or a fibrous substrate made of ultrafine fibers is impregnated with an aqueous dispersion containing a polymer elastic precursor having hydrophilic groups and a compound having an ethylene oxide skeleton represented by general formula (1) in an amount of 0.1 parts by mass to 5% by mass per 100 parts by mass of the solid content of the polymer elastic precursor, and then the polymer elastic precursor is coagulated. Details are described below.

[0091] <Formation process of fibrous base material> In the present invention, it is preferable to use ultrafine fiber-generating fibers as a means of obtaining ultrafine fibers. By first entangling ultrafine fiber-generating fibers to form a nonwoven fabric, and then further miniaturizing the fibers, a nonwoven fabric can be obtained in which bundles of ultrafine fibers are entangled.

[0092] As a type of ultrafine fiber generating fiber, it is preferable to use a sea-island type composite fiber in which two thermoplastic resins with different solvent solubility (two or three components in the case of core-sheath composite fibers) are used as the sea component and island component, and the sea component is dissolved and removed using a solvent or the like to form the island component into ultrafine fibers. This is preferable from the viewpoint of texture and surface quality of the artificial leather base material because when the sea component is removed, appropriate voids can be provided between the island components, i.e., between the ultrafine fibers inside the fiber bundle.

[0093] As for sea-island type composite fibers, a method using a polymer interconnected array that is spun by using a sea-island type composite die and interconnecting two components (three components if the island is a core-sheath composite fiber) of sea component and island component is preferred from the viewpoint of obtaining ultrafine fibers with a uniform single fiber diameter.

[0094] As the marine component of sea-island type composite fibers, polyethylene, polypropylene, polystyrene, copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid or polyethylene glycol, and polylactic acid can be used, but from the viewpoint of spinnability and ease of elution, polystyrene and copolymerized polyester are preferably used.

[0095] In the sea-island type composite fiber used in the present invention, the mass ratio of sea component to island component is preferably in the range of sea component:island component = 10:90 to 80:20. When the mass ratio of sea component is 10% by mass or more, the island component is easily made sufficiently fine. Furthermore, when the mass ratio of sea component is 80% by mass or less, productivity is improved because the proportion of eluted components is low. More preferably, the mass ratio of sea component to island component is in the range of sea component:island component = 20:80 to 70:30.

[0096] Furthermore, the fibrous base material is preferably in the form of a nonwoven fabric in which fibers are intertwined. As mentioned above, both short-fiber and long-fiber nonwoven fabrics can be used, but a short-fiber nonwoven fabric is preferable because it has more fibers oriented in the thickness direction of the artificial leather compared to a long-fiber nonwoven fabric, resulting in a high level of density on the surface of the artificial leather when it is napped.

[0097] When a short-fiber nonwoven fabric is used as the fibrous base material, the obtained ultrafine fiber-generating fibers are preferably crimped and cut to a predetermined length to obtain raw cotton. Known methods can be used for crimping and cutting.

[0098] Next, the obtained raw cotton is formed into a fiber web using a cross wrapper or the like, and then entangled to obtain a short-fiber nonwoven fabric. Methods such as needle punching or water jet punching can be used to entangle the fiber web and obtain a short-fiber nonwoven fabric.

[0099] Furthermore, it is preferable to laminate the obtained short-fiber nonwoven fabric with a woven fabric and then entangle and integrate them. For entanglement and integration of the short-fiber nonwoven fabric and the woven fabric, it is preferable to laminate the woven fabric on one or both sides of the short-fiber nonwoven fabric, or to sandwich the woven fabric between multiple short-fiber nonwoven fabric webs and then entangle the fibers of the short-fiber nonwoven fabric and the woven fabric by processes such as needle punching or water jet punching.

[0100] The apparent density of a short-fiber nonwoven fabric made of ultrafine fibers after needle punching or water jet punching is 0.15 g / cm³. 3 More than 0.45g / cm 3 Preferably, the apparent density is 0.15 g / cm³. 3 By doing so, the fibrous substrate can obtain sufficient morphological and dimensional stability. On the other hand, the apparent density is preferably 0.45 g / cm³. 3 By doing the following, it is possible to maintain sufficient space for imparting the polymeric elastic precursor.

[0101] From the viewpoint of densification, it is preferable that the nonwoven fabric obtained in this manner be shrunk by dry heat, wet heat, or both, and further increased in density. The nonwoven fabric can also be compressed in the thickness direction by calendering or the like.

[0102] When using sea-island type composite fibers, the desalination treatment to remove the marine component from the composite fibers can be performed before and / or after applying an aqueous dispersion containing a polymer elastic precursor having hydrophilic groups to the fibrous substrate. Performing the desalination treatment before applying the aqueous dispersion tends to result in a structure where the polymer elastic material adheres directly to the ultrafine fibers, allowing for a strong grip on the ultrafine fibers and thus improving the abrasion resistance of the artificial leather. Performing the desalination treatment after applying the aqueous dispersion creates an appropriate space between the ultrafine fibers and the polymer elastic material, making the texture of the artificial leather more flexible.

[0103] When using sea-island composite fibers, the fiber thinning treatment (de-sea treatment) can be performed, for example, by immersing the sea-island composite fibers in a solvent and then squeezing out the liquid. As a solvent to dissolve the sea components, an alkaline aqueous solution such as sodium hydroxide or hot water can be used.

[0104] In the ultrafine fiber development process, equipment such as continuous staining machines, vibro-washer type desalination machines, liquid flow staining machines, Wins staining machines, and Zigger staining machines can be used.

[0105] On the other hand, by applying an inhibitor such as a cellulose derivative or polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) to a fibrous substrate, and then applying an aqueous dispersion, the adhesion between the fibrous substrate and the polymeric elastic material can be reduced, and a more flexible texture can also be achieved.

[0106] The aforementioned inhibitor application can be performed either before or after the desalination treatment of the sea-island structure fibers. By applying the inhibitor before desalination, the shape retention of the fibrous substrate can be increased even when the basis weight of the fibers decreases and the tensile strength of the fibrous substrate declines. Therefore, thin artificial leather can be processed stably, and the thickness retention rate of the fibrous substrate during the desalination process can be increased, suppressing the densification of the fibrous substrate. On the other hand, by applying the inhibitor after desalination, the fibrous substrate can be made denser, so it is preferable to adjust the application as appropriate depending on the purpose.

[0107] As the aforementioned inhibitor, PVA is preferably used because it has a high reinforcing effect on fibrous substrates and is not easily eluted in water. Among PVAs, it is more preferable to use highly saponified PVA, which is less soluble in water, from the viewpoint that the inhibitor is less likely to elute when an aqueous dispersion containing a polymer elastomer precursor having hydrophilic groups is applied, and that it can more effectively inhibit adhesion between ultrafine fibers and polymer elastomers.

[0108] Highly saponified PVA is preferably saponified to 95% or more and 100% or less, and more preferably 98% or more and 100% or less. By increasing the saponification degree to 95% or more, it is possible to suppress the elution of PVA when an aqueous dispersion containing a polymeric elastic precursor having hydrophilic groups is applied.

[0109] The degree of polymerization of PVA is preferably 500 to 3500, and more preferably 500 to 2000. By setting the degree of polymerization of PVA to 500 or higher, the elution of PVA when an aqueous dispersion containing a polymeric elastic precursor is applied can be suppressed. Furthermore, by setting the degree of polymerization of PVA to 3500 or lower, the viscosity of the PVA solution does not become too high, and high-saponification PVA can be stably applied to the fibrous substrate.

[0110] The amount of PVA added to the fibrous substrate is 0.1% by mass or more and 50% by mass or less, preferably 1% by mass or more and 45% by mass or less, relative to the fiber mass of the fibrous substrate. By adding 0.1% by mass or more of PVA, a sheet material with good flexibility and texture can be obtained, and by adding 50% by mass or less of PVA, a sheet material with good processability and better physical properties such as abrasion resistance can be obtained.

[0111] <Process for imparting polymeric elasticity> The present invention provides a method for producing artificial leather, in which an ultrafine fiber-generating fiber or a fibrous substrate made of ultrafine fibers is impregnated with an aqueous dispersion containing a polymer elastic precursor having hydrophilic groups and a compound having an ethylene oxide skeleton represented by general formula (1) in an amount of 0.1 parts by mass to 5 parts by mass per 100 parts by mass of the solid content of the polymer elastic precursor, and then the polymer elastic precursor is coagulated.

[0112] In the method for producing artificial leather of the present invention, a polymeric elastic precursor having hydrophilic groups is applied to a fibrous base material.

[0113] In the method for producing artificial leather of the present invention, it is preferable that the polymeric elastic precursor contains polyetherdiol and / or polycarbonatediol as constituent components. The reason is as described in section (1-6) Composition of the polymeric elastic precursor above.

[0114] In the method for manufacturing artificial leather of the present invention, the coagulation of the polymer elastic material precursor can be performed using coagulation methods commonly used in this field, such as dry heat coagulation or liquid coagulation. However, in dry heat coagulation, compounds having an ethylene oxide skeleton tend to separate from the polymer elastic material being coagulated due to migration caused by the evaporation of water during heating. Therefore, it is more preferable to use liquid coagulation, in which compounds having an ethylene oxide skeleton are more easily incorporated into the polymer elastic material.

[0115] When using the dry heat coagulation method, it is preferable to apply an aqueous dispersion to the fibrous substrate, then heat-treat it at a temperature of 120°C to 180°C to induce dry heat coagulation, thereby imparting a polymeric elastic material precursor to the fibrous substrate.

[0116] Furthermore, as a liquid-based coagulation method, an acid coagulation method using a coagulation solvent with a pH of 1 to 3 or a hot water coagulation method using hot water at a temperature of 80°C to 100°C can be used.

[0117] When using the acid coagulation method as the liquid coagulation method, the coagulation solvent should have a pH of 1 or higher, preferably 1.5 or higher, to prevent deterioration of the polymer elastic precursor. Alternatively, a pH of 3 or lower, preferably 2.5 or lower, can promote coagulation of the polymer elastic precursor. The liquid temperature of the coagulation solvent is preferably 20°C or higher, more preferably 30°C or higher, and even more preferably 40°C or higher, in order to promote coagulation of the polymer elastic precursor. Furthermore, to prevent deterioration of the polymer elastic precursor, the liquid temperature of the coagulation solvent is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower. While there are no particular limitations on the type of coagulation solvent, formic acid, sulfuric acid, etc., are preferably used from the viewpoint of ease of handling.

[0118] The concentration of the polymeric elastic precursor in the aqueous dispersion (content of polymeric elastic precursor in 100 parts by mass of the aqueous dispersion) is preferably 10 parts by mass or more and 50 parts by mass or less, and more preferably 15 parts by mass or more and 40 parts by mass or less, from the viewpoint of storage stability of the aqueous dispersion.

[0119] The aqueous dispersion used in the present invention may contain 40 parts by mass or less of a water-soluble organic solvent per 100 parts by mass of the aqueous dispersion in order to improve storage stability and film-forming properties. However, from the viewpoint of preserving the film-forming environment, it is preferable that the content of the water-soluble organic solvent be 1 part by mass or less.

[0120] In the method for manufacturing artificial leather of the present invention, when using a dry heat solidification method, an inorganic salt can be included in the aqueous dispersion. By including an inorganic salt, the aqueous dispersion can be imparted with heat-sensitive solidification properties. In the present invention, heat-sensitive solidification refers to the property that when the aqueous dispersion is heated, its fluidity decreases and it solidifies when it reaches a certain temperature (heat-sensitive solidification temperature).

[0121] When using the dry heat solidification method, if the polymeric elastic precursor is not heat-sensitive, a migration phenomenon occurs where the polymeric elastic precursor moves to the sheet surface as the water evaporates. Furthermore, as solidification progresses with the polymeric elastic precursor unevenly distributed around the fibers as the water evaporates, the polymeric elastic material surrounds the fibers, creating a structure that strongly restricts their movement. As a result, the texture of the artificial leather hardens significantly.

[0122] In the method for producing artificial leather of the present invention, it is preferable to include a crosslinking agent in the aqueous dispersion. By introducing a three-dimensional network structure into the polymeric elastic material using the crosslinking agent, physical properties such as abrasion resistance can be improved.

[0123] By setting the concentration of the crosslinking agent in the aqueous dispersion to 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of polymer elastic material precursor, a greater number of three-dimensional network structures can be introduced into the polymer elastic material by the crosslinking agent, resulting in artificial leather with excellent abrasion resistance and other properties. Furthermore, by setting the concentration of the crosslinking agent to 10 parts by mass or less, more preferably 7 parts by mass or less, per 100 parts by mass of polymer elastic material precursor, it is possible to suppress the inhibition of the solidification of the polymer elastic material precursor by an excess of crosslinking agent when the polymer elastic material is formed, thereby making it easier to suppress the deterioration of physical properties such as abrasion resistance.

[0124] Furthermore, the crosslinking agent in the method for producing artificial leather of the present invention is preferably a carbodiimide-based crosslinking agent and / or a blocked isocyanate crosslinking agent. The crosslinking agent can impart a three-dimensional crosslinked structure to the molecules of the polymer elastic material in the artificial leather by N-acylurea bonds and / or isourea bonds, which have excellent physical properties such as light resistance, heat resistance, and abrasion resistance, as well as flexibility. This makes it possible to dramatically improve physical properties such as durability and abrasion resistance while maintaining the flexibility of the artificial leather.

[0125] In the method for producing artificial leather of the present invention, it is preferable that the aqueous dispersion contains a compound having an ethylene oxide skeleton of general formula (1). The viscosity of the aqueous dispersion described later can be adjusted by the compound having an ethylene oxide skeleton of general formula (1), and the migration phenomenon in which the polymer elastic precursor moves to the sheet surface as water evaporates can be suppressed.

[0126] In addition, in the present invention, a thickening agent can be used in combination with a compound having the ethylene oxide skeleton of general formula (1). This "thickening agent" is one that, when included in an aqueous dispersion, can adjust the viscosity of the aqueous dispersion, and such thickening agents can be nonionic, anionic, cationic, or biionic.

[0127] The types of thickeners mentioned above can be selected from association-type thickeners and water-soluble polymer-type thickeners.

[0128] As associative thickeners, urethane-modified compounds, acrylic-modified compounds, and copolymers thereof can be used.

[0129] Examples of water-soluble polymer-type thickeners include natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds.

[0130] Examples of natural polymer compounds include nonionic compounds such as tamarind gum, guar gum, roasted bean gum, tragacanth gum, starch, dextrin, gelatin, agarose, casein, and curdlan; anionic compounds such as xanthan gum, carrageenan, gum arabic, pectin, collagen, chondroitin sulfate sodium, hyaluronic acid sodium, carboxymethyl starch, and starch phosphate; and cationic compounds such as cationic starch and chitosan.

[0131] Examples of semi-synthetic polymer compounds include nonionic compounds such as methylcellulose, ethylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, methylhydroxypropylcellulose, soluble starch, and methyl starch, as well as anionic compounds such as carboxymethylcellulose, carboxymethyl starch, and alginates.

[0132] Examples of synthetic polymer compounds include nonionic compounds such as polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polymethyl vinyl ether, polyethylene glycol, and polyisopropylacrylamide; anionic compounds such as carboxyvinyl polymer, sodium polyacrylate, and sodium polystyrene sulfonate; and cationic compounds such as dimethylaminoethyl (meth)acrylate quaternary salt, dimethyldiallylammonium chloride, polyamidine, polyvinylimidazoline, and polyethyleneimine.

[0133] In the method for manufacturing artificial leather of the present invention, a polymer elastic precursor may be applied to a fibrous substrate, solidified, and then a curing treatment may be performed. The heating temperature for the curing treatment by drying is 120°C to 180°C. To enhance the effect of the curing treatment and improve physical properties such as durability and abrasion resistance, the temperature is preferably 140°C or higher, more preferably 145°C or higher. To suppress thermal degradation of the polymer elastic, the temperature is preferably 175°C or lower, more preferably 170°C or lower.

[0134] <Finishing Process> The present invention's method for manufacturing artificial leather preferably includes a dyeing step for dyeing the artificial leather. Various methods commonly used in the art can be used for this dyeing process. For example, immersion dyeing treatments such as liquid flow dyeing using a jigger dyeing machine or liquid flow dyeing machine, thermosol dyeing treatment using a continuous dyeing machine, or printing treatments on the napped surface using roller printing, screen printing, inkjet printing, sublimation printing, and vacuum sublimation printing can be used. In particular, it is preferable to use a liquid flow dyeing machine because it can soften the unnapped artificial leather or artificial leather by simultaneously applying a kneading effect while dyeing it. Furthermore, various resin finishing processes can be applied after dyeing as needed.

[0135] The dyes used in this invention are not particularly limited and can be selected according to the type of fiber constituting the fibrous base material. For example, disperse dyes can be used for polyester fibers, acid dyes or metal-containing dyes can be used for polyamide fibers, and combinations thereof can also be used. When dyeing with disperse dyes, reductive washing may be performed after dyeing.

[0136] It is also preferable to use dyeing aids during the dyeing process. By using dyeing aids, the uniformity and reproducibility of the dyeing can be improved. Furthermore, a finishing treatment using, for example, a softener such as silicone, an antistatic agent, a water repellent, a flame retardant, a lightfastening agent, and an antibacterial agent can be applied in the same bath as the dyeing process or after dyeing.

[0137] In this invention, from the viewpoint of manufacturing efficiency, it is also preferable to cut the material in half in the thickness direction, whether before or after the dyeing process.

[0138] The method for manufacturing artificial leather of the present invention may preferably include a napping process, either before or after the dyeing process. The method for forming the nap is not particularly limited, and various methods commonly used in this field, such as buffing with sandpaper, can be used. Since a nap length that is too short makes it difficult to obtain an elegant appearance, and a nap length that is too long tends to cause pilling, it is preferable that the nap length be between 0.2 mm and 1.0 mm.

[0139] When applying a napped finish, a lubricant such as a silicone emulsion can be applied to the surface of the artificial leather before the napping process. Additionally, applying an antistatic agent before the napping process reduces the accumulation of grinding dust on the sandpaper. In this way, the artificial leather is formed.

[0140] Furthermore, in one embodiment of the present invention, decorative features can be applied to the surface as needed. For example, post-processing treatments such as perforation, embossing, laser processing, pin sonic processing, and printing can be applied. [Examples]

[0141] Next, the artificial leather of the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[0142] [Evaluation Method] (1) Evaluation of the flexibility of artificial leather Based on the "41.5° cantilever method" described in 6.7.3 of JIS L1913:2010 "General Nonwoven Fabric Testing Methods," six 25mm x 250mm test specimens were prepared in the longitudinal direction. These were placed on a horizontal table with a 41.5° inclined surface, and the specimens were slid along the surface. The scale was read when the center point of one end of the specimen touched the inclined surface, and the average bending length of the six specimens was calculated.

[0143] (2) Accelerated deterioration test of artificial leather As an accelerated degradation test, we conducted an accelerated degradation test (jungle test) using ESPEC Corporation's "PR-2J" by leaving a 10cm square piece of artificial leather undisturbed for two weeks in a space at 70°C and 95% relative humidity.

[0144] (3) Abrasion evaluation of artificial leather Abrasion evaluation was conducted in accordance with JIS L1096:2010. A James H. Heal & Co. "Model 406" abrasion tester was used as the Martindale abrasion tester, and the company's "ABRASTIVE CLOTH SM25" was used as the standard friction cloth. A load of 12 kPa was applied to the artificial leather after the aforementioned accelerated degradation test, and the number of abrasion cycles was 50,000. Using the mass of the artificial leather before and after abrasion, the abrasion loss was calculated using the following formula.

[0145] Weight loss due to wear (mg) = Mass before wear (mg) - Mass after wear (mg) The wear loss was calculated by rounding the value to the first decimal place.

[0146] (4) Content of compounds having an ethylene oxide skeleton Artificial leather was immersed overnight in N,N-dimethylformamide, and the resulting solution containing the eluted polymeric elastic material and the compound having an ethylene oxide skeleton was concentrated and solidified by heating and drying at 140°C. To the obtained solid, toluene at 25°C was added to eluate only the compound having an ethylene oxide skeleton. After heating and drying the solution containing the compound having an ethylene oxide skeleton, the amount of the compound having an ethylene oxide skeleton per 100 parts by mass of polymeric elastic material was measured.

[0147] (5) Viscosity of an aqueous dispersion containing a compound having an ethylene oxide skeleton The aqueous dispersion containing the prepared polymeric elastic precursor and the compound having an ethylene oxide skeleton was measured at a liquid temperature of 25°C in accordance with JIS K7117-1 (1999).

[0148] [Method for manufacturing nonwoven fabric A for fibrous base material] Using 8 mol% copolymer polyester of SSIA (sodium 5-sulfoisophthalate) as the sea component and polyethylene terephthalate as the island component, a sea-island type composite fiber was obtained with a composite ratio of 43% by mass of sea components and 57% by mass of island components, resulting in 16 islands per filament and an average single fiber diameter of 20 μm. The obtained sea-island type composite fiber was cut to a fiber length of 51 mm and stapled, and a fiber web was formed by passing it through a card and a cross wrapper. Needle punching was then performed to obtain a basis weight of 550 g / m². 2 A nonwoven fabric with a thickness of 3.0 mm was then manufactured. The nonwoven fabric obtained in this way was immersed in hot water at 98°C for 2 minutes to shrink it, and then dried at 100°C for 5 minutes to obtain nonwoven fabric A for fibrous base material.

[0149] [Method for manufacturing nonwoven fabric B for fibrous base material] Using 8 mol% copolymer polyester of SSIA (sodium 5-sulfisophthalate) as the sea component and polyethylene terephthalate as the island component, a sea-island type composite fiber was obtained with a composite ratio of 43% by mass of sea components and 57% by mass of island components, resulting in 16 islands per filament and an average single fiber diameter of 28.9 μm. The obtained sea-island type composite fiber was cut to a fiber length of 51 mm and stapled, and a fiber web was formed by passing it through a card and a cross wrapper. Needle punching was then performed to obtain a basis weight of 550 g / m². 2 A nonwoven fabric with a thickness of 3.0 mm was then manufactured. The nonwoven fabric obtained in this way was immersed in hot water at 98°C for 2 minutes to shrink it, and then dried at 100°C for 5 minutes to obtain nonwoven fabric B for fibrous base materials.

[0150] [Method for producing polymeric elastic precursor A] A prepolymer was prepared in acetone solvent using polyhexamethylene carbonate with a number-average molecular weight (Mn) of 2000 as the polymeric polyol, dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI) as the organic diisocyanate, and a diol compound with polyethylene glycol in its side chain and 2,2-dimethylolpropionic acid as hydrophilic active hydrogen component-containing compounds. Ethylene glycol, ethylenediamine, and water were added as chain extenders and the mixture was stirred. The acetone was removed under reduced pressure to obtain an aqueous dispersion of polymeric elastic precursor A.

[0151] [Example 1] (Formation process of fibrous base material) A 10% by mass aqueous solution of PVA (NM-14, manufactured by Nippon Synthetic Chemical Co., Ltd.) with a degree of saponification of 99% and a degree of polymerization of 1400 was impregnated into a nonwoven fabric A for fibrous substrates, and the fabric was heated and dried at 140°C for 10 minutes to obtain a PVA-contained sheet in which the amount of PVA attached to the fibrous nonwoven fabric was 30% by mass relative to the fiber mass.

[0152] The obtained PVA-treated sheet was immersed in an 8 g / L sodium hydroxide aqueous solution heated to 95°C for 30 minutes to obtain a fibrous base material (PVA-treated ultrafine fiber nonwoven fabric) consisting of ultrafine fibers from which the marine component of the sea-island type composite fiber had been removed.

[0153] (Process of imparting polymeric elasticity) To 100 parts by mass of the solid content of polymer elastic precursor A, 1.5 parts by mass of a compound having an ethylene oxide skeleton represented by the following general formula (3) (viscosity: 6000 mPa·s, number average molecular weight: 2000, number of repeating units of the ethylene oxide skeleton (n): 50) was added (in Table 1, the solid content of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solid content of this polymer elastic precursor is abbreviated as "content in aqueous dispersion"). 5 parts by mass of a blocked isocyanate crosslinking agent (Covestro's "IMPRAFIX2794") and 3 parts by mass of an acrylic thickener were added. The overall solid content was then adjusted to 19% by mass with water to obtain an aqueous dispersion containing the polymer elastic precursor with a viscosity of 2000 mPa·s. After impregnating the PVA-modified ultrafine fiber nonwoven fabric with the aqueous dispersion, the polymer elastic precursor A was coagulated by treating it with a pH 2.3 formic acid aqueous solution at 60°C for 20 minutes, and then curing it (drying with hot air at 160°C for 20 minutes) to obtain a polymer elastic ultrafine fiber nonwoven fabric with a thickness of 2.00 mm, in which 50 parts by mass of polymer elastic material were added to 100 parts by mass of ultrafine fibers of the PVA-modified ultrafine fiber nonwoven fabric.

[0154] The resulting polymeric elastic nonwoven fabric was immersed in water heated to 95°C for 10 minutes to remove the applied PVA and obtain artificial leather.

[0155] [ka]

[0156] (Finishing process) The obtained artificial leather was cut in half perpendicular to the thickness direction, and the opposite side of the cut surface was ground with 180-grit endless sandpaper to obtain artificial leather with a pile that was 0.75 mm thick.

[0157] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 70 mm and a wear loss of 15 mg after an accelerated degradation test (jungle test), demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymeric elastic material of the artificial leather (abbreviated as "content in polymeric elastic material" in Table 1) was 0.7 parts by mass per 100 parts by mass of polymeric elastic material. The results are shown in Table 1.

[0158] [Example 2] The procedure was carried out in the same manner as in Example 1, except that the amount of solids of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solids of polymer elastic precursor A, and the viscosity of the aqueous dispersion containing polymer elastic precursor A were changed.

[0159] The resulting artificial leather with a raised nap was dyed black using a jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 90 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 20 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymeric elastic material of the artificial leather was 0.5 parts by mass per 100 parts by mass of the polymeric elastic material. The results are shown in Table 1.

[0160] [Example 3] The procedure was carried out in the same manner as in Example 1, except that the amount of solids of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solids of polymer elastic precursor A, and the viscosity of the aqueous dispersion containing polymer elastic precursor A were changed.

[0161] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 55 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 28 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymeric elastic material of the artificial leather was 2.0 parts by mass per 100 parts by mass of the polymeric elastic material. The results are shown in Table 1.

[0162] [Example 4] The procedure was carried out in the same manner as in Example 1, except that the solution viscosity when the compound having an ethylene oxide skeleton was dissolved in water, the number-average molecular weight, the number of repeating units (n) of the ethylene oxide skeleton, and the solid content of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solid content of polymer elastic precursor A were changed.

[0163] The resulting artificial leather with a raised nap was dyed black using a liquid flow dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 110 mm, and the abrasion loss after an accelerated degradation test (jungle test) was 25 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymer elastic material of the artificial leather was 1.0 part by mass per 100 parts by mass of the polymer elastic material. The results are shown in Table 1.

[0164] [Example 5] The procedure was carried out in the same manner as in Example 1, except that the solution viscosity, number-average molecular weight, number of repeating units (n) of the ethylene oxide skeleton, and viscosity of the aqueous dispersion containing the polymer elastic precursor were changed when the compound having an ethylene oxide skeleton was dissolved in water.

[0165] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 120 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 30 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymeric elastic material of the artificial leather was 0.9 parts by mass per 100 parts by mass of the polymeric elastic material. The results are shown in Table 1.

[0166] [Example 6] The procedure was carried out in the same manner as in Example 1, except that the PVA-containing ultrafine fiber nonwoven fabric was impregnated with an aqueous dispersion, and then the polymer elastic material precursor A was dry-heat solidified by dry heat treatment with hot air at 120°C for 20 minutes.

[0167] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 120 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 30 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymer elastic material of the artificial leather was 0.2 parts by mass per 100 parts by mass of the polymer elastic material. The results are shown in Table 1.

[0168] [Example 7] The procedure was carried out in the same manner as in Example 1, except that nonwoven fabric B for fibrous base materials was used as the nonwoven fabric for fibrous base materials.

[0169] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 5.5 μm. The resulting artificial leather had a bending length of 100 mm, and the abrasion loss after an accelerated degradation test (jungle test) was 18 mg, demonstrating a flexible texture and excellent durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymeric elastic material of the artificial leather was 0.7 parts by mass per 100 parts by mass of the polymeric elastic material. The results are shown in Table 1.

[0170] [Comparative Example 1] The procedure was carried out in the same manner as in Example 1, except that no compound having an ethylene oxide skeleton was added.

[0171] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 160 mm, and the abrasion loss after an accelerated degradation test (jungle test) was 38 mg, indicating a hard texture and poor durability. The results are shown in Table 2.

[0172] [Comparative Example 2] The procedure was carried out in the same manner as in Example 1, except that the amount of solids of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the polymer elastic precursor A, and the viscosity of the aqueous dispersion containing the polymer elastic precursor were changed.

[0173] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 190 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 40 mg, indicating a hard texture and poor durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymer elastic material of the artificial leather was 5.5 parts by mass per 100 parts by mass of the polymer elastic material. The results are shown in Table 2.

[0174] [Comparative Example 3] The procedure was carried out in the same manner as in Example 1, except that the solid content of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solid content of polymer elastic precursor A, the viscosity of the solution when the compound having an ethylene oxide skeleton is dissolved in water, the number-average molecular weight, the number of repeating units (n) of the ethylene oxide skeleton, and the viscosity of the aqueous dispersion containing polymer elastic precursor A were changed.

[0175] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 170 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 33 mg, indicating a hard texture and poor durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymer elastic material of the artificial leather was 1.5 parts by mass per 100 parts by mass of the polymer elastic material. The results are shown in Table 2.

[0176] [Comparative Example 4] The procedure was carried out in the same manner as in Example 1, except that the solid content of the compound having an ethylene oxide skeleton relative to 100 parts by mass of the solid content of polymer elastic precursor A, the viscosity of the solution when the compound having an ethylene oxide skeleton is dissolved in water, the number-average molecular weight, the number of repeating units (n) of the ethylene oxide skeleton, and the viscosity of the aqueous dispersion containing polymer elastic precursor A were changed.

[0177] The resulting artificial leather with a raised nap was dyed black using a liquid jet dyeing machine at a temperature of 120°C. It was then dried in a dryer to obtain artificial leather with an average single fiber diameter of 3.8 μm. The resulting artificial leather had a bending length of 220 mm, and the abrasion loss after the accelerated degradation test (jungle test) was 50 mg, indicating a hard texture and poor durability. Furthermore, the content of compounds with an ethylene oxide skeleton in the polymer elastic material of the artificial leather was 0.6 parts by mass per 100 parts by mass of the polymer elastic material. The results are shown in Table 2.

[0178] [Table 1]

[0179] [Table 2] [Industrial applicability]

[0180] The artificial leather obtained by the present invention can be suitably used as an interior material having a very elegant appearance, such as furniture, chairs and wall materials, seats, ceilings and interiors in the interiors of automobiles, trains and aircraft, uppers and trims of shoes such as shirts, jackets, casual shoes, sports shoes, men's and women's shoes, bags, belts, wallets, and clothing materials used in parts thereof, as well as industrial materials such as wiping cloths, abrasive cloths and CD curtains.

Claims

1. Artificial leather comprising a fibrous base material consisting of ultrafine fibers with an average single fiber diameter of 0.1 μm or more and 10 μm or less, and a polymeric elastic body, wherein the polymeric elastic body comprises a compound having a hydrophilic group and a compound having an ethylene oxide skeleton represented by the following general formula (1), and the content of the compound having the ethylene oxide skeleton in the polymeric elastic body of the artificial leather is 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the polymeric elastic body. 【Chemistry 1】 Here, R ２ R is a functional group having 1 to 20 carbon atoms, where n represents the number of repeating units from 10 to 200. R1 is a functional group having an ester bond as shown in general formula (2). 【Chemistry 2】 Here, R3 is an alkyl group having 1 to 19 carbon atoms and an aryl group having 1 to 19 carbon atoms.

2. R in the general formula (2) ３ The artificial leather according to claim 1, wherein the functional group includes a terminal group selected from the group consisting of an isopropyl group, a tert-butyl group, and a mesityl group.

3. A method for producing artificial leather according to claim 1 or 2, comprising impregnating an ultrafine fiber-generating fiber or a fibrous substrate made of ultrafine fibers with an aqueous dispersion containing a polymer elastic precursor having hydrophilic groups and a compound having an ethylene oxide skeleton represented by the general formula (1) in an amount of 0.1 parts by mass to 5 parts by mass per 100 parts by mass of the solid content of the polymer elastic precursor, and then coagulating the polymer elastic precursor.

4. The method for producing artificial leather according to claim 3, wherein the viscosity of the aqueous dispersion is 1,000 mPa·s or more and 10,000 mPa·s or less.

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