Laminate and synthetic leather

Abstract

This laminate comprises a substrate (i) and a urethane foam layer (ii), wherein the urethane foam layer (ii) is in direct contact with the substrate (i), the urethane foam layer (ii) contains a urethane resin (A) having a nonionic group, and the flow start temperature of the urethane resin (A) is greater than 130 °C.

Description

Laminate and synthetic leather

[0001] This application claims priority to Japanese Patent Application No. 2023-193111, filed on November 13, 2023, the contents of which are incorporated herein by reference.

[0002] Due to their excellent mechanical strength and texture, urethane resins are widely used in the production of synthetic leathers, including artificial leathers. Until now, solvent-based urethane resins containing N,N-dimethylformamide (DMF) have been the mainstream for synthetic leather applications. However, due to DMF restrictions in Europe, strengthened VOC emission regulations in China and Taiwan, and DMF restrictions imposed by major apparel manufacturers, there is a demand for DMF-free urethane resin compositions for each layer of synthetic leather. Among these, water-based urethanes (PUDs), in which urethane resins are dispersed in water, are being considered as an alternative raw material for the intermediate porous layer formed by wet coagulation of conventional solvent-based urethane resins.

[0003] For example, Patent Document 1 discloses a foam-forming composition characterized by containing (A) a first self-emulsifying aqueous polyurethane resin having at least one hydrophilic functional group selected from the group consisting of a sulfo group and a sulfonate group, (B) a second self-emulsifying aqueous polyurethane resin having at least one hydrophilic functional group selected from the group consisting of a carboxy group and a carboxylate group, (C) a crosslinking agent, (D) a foaming agent, (E) a thickener, and (F) water, and a leather material having a foamed resin layer made of a foamed and cured product of the foam-forming composition.

[0004] However, conventional synthetic leathers such as those described in Patent Document 1 require an adhesive layer between the substrate and the urethane foam layer, which necessitates a relatively long period of aging, resulting in productivity problems.

[0005] Furthermore, in recent years, there has been a demand for synthetic leather that has a soft feel while also offering good processability, such as making the uneven patterns on the surface of the synthetic leather more clearly visible when embossed. However, there has been no synthetic leather that satisfies these increasingly increasing requirements, and there has been no synthetic leather that satisfies current market demands.

[0006] Therefore, there has been a demand for a laminate that is easy to peel, has a soft texture, and is also easy to process, and for a synthetic leather having such a laminate.

[0007] Japanese Patent Application Laid-Open No. 2020-109152

[0008] An object of the present invention is to provide a laminate that has quick peelability, a soft texture, and good processability, and to provide a synthetic leather having the laminate.

[0009] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that by using a urethane resin having a specific structure and exceeding a specific flow initiation temperature, and by configuring a structure in which the substrate (i) and the urethane foam layer (ii) are in direct contact with each other, it is possible to prepare a laminate that has easy peelability, a soft texture, and good processability, and have completed the present invention.

[0010] That is, the present invention has the following aspects. [1] A laminate including a substrate (i) and a urethane foam layer (ii), wherein the urethane foam layer (ii) is in direct contact with the substrate (i), and the urethane foam layer (ii) contains a urethane resin (A) having a nonionic group, the urethane resin (A) having a flow-initiation temperature of greater than 130°C. [2] The laminate according to [1], wherein the urethane resin (A) has a flow-initiation temperature of 150°C or higher. [3] The laminate according to [1] or [2], wherein the urethane resin (A) is a urethane resin made from a polyisocyanate and one or more polyols selected from the group consisting of a polyether polyol, a polycarbonate polyol, and a polyester polyol. [4] The laminate according to any one of [1] to [3], wherein the urethane foam layer (ii) further contains a surfactant. [5] The laminate according to [4], wherein the surfactant is a long-chain carboxylate salt. [6] The dry density of the urethane foam layer (ii) is 200 to 1000 kg / m ３ [7] A synthetic leather having the laminate according to any one of [1] to [6].

[0011] According to the present invention, it is possible to provide a laminate that has quick peelability, a soft texture, and good processability, and a synthetic leather having the laminate.

[0012] 1 is an SEM image of the laminate of Example 1. FIG. 2 is an SEM image of the laminate of Comparative Example 2.

[0013] (Laminate) The laminate of this embodiment includes a substrate (i) and a urethane foam layer (ii). In the laminate of this embodiment, the urethane foam layer (ii) is in direct contact with the substrate (i). That is, the laminate of this embodiment does not have an adhesive layer between the substrate (i) and the urethane foam layer (ii).

[0014] <Substrate (i)> Examples of the substrate (i) that can be used include fiber substrates such as nonwoven fabrics, woven fabrics, and knitted fabrics made from polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, hemp, silk, wool, glass fibers, carbon fibers, and blends thereof; nonwoven fabrics impregnated with resins such as polyurethane resins; nonwoven fabrics further provided with a porous layer; and resin substrates such as thermoplastic urethane (TPU).

[0015] <Urethane foam layer (ii)> The dry density of the urethane foam layer (ii) is 200 to 1000 kg / m ３ The dry density of the urethane foam layer (ii) is the value obtained by subtracting the weight of the substrate (i) per 10 cm square from the weight of the laminate per 10 cm square, and dividing the result by the thickness of the urethane foam layer (ii).

[0016] The dry density of the urethane foam layer (ii) can be controlled by the expansion ratio, which can be controlled by the type of urethane used and the stirring speed and time during foaming.

[0017] The thickness of the urethane foam layer (ii) is, for example, 50 to 600 μm.

[0018] The urethane foam layer (ii) contains a urethane resin (A) having a nonionic group (hereinafter also referred to as "component (A)").

[0019] <<Urethane Resin (A) Having Nonionic Groups>> Component (A) is a urethane resin having nonionic groups and is dispersible in water. Component (A) has superior hydrolysis properties compared to other water-dispersible urethane resins (e.g., anionic urethane resins). Furthermore, since no crosslinking agent needs to be added, it has excellent processability.

[0020] The flow initiation temperature of component (A) is greater than 130° C., preferably greater than 150° C., and more preferably greater than 160° C. When the flow initiation temperature of component (A) is greater than 130° C., the peel strength is improved. Furthermore, when the flow initiation temperature of component (A) is equal to or greater than the above-mentioned preferable lower limit, the peel strength is further improved.

[0021] There is no particular upper limit to the flow temperature of component (A), but it is preferably 250°C or lower, for example.

[0022] The flow initiation temperature of component (A) can be controlled, for example, by appropriately adjusting the length of the molecular chain of the urethane resin. Specifically, it can be controlled by the amount of chain extender (a3) ​​added in the "chain extension step" described below. The flow initiation temperature of component (A) can be controlled, for example, by the type of polyol (a2), the amount of chain extender (a2-1) used, and the type of polyisocyanate (a1), which are raw materials for urethane resin (A) described below. Methods for adjusting the flow initiation temperature of component (A) to a high level include, for example, using a polyol with high crystallinity such as polycarbonate polyol as polyol (a2), increasing the amount of chain extender (a2-1) used, or using a polyisocyanate with high crystallinity such as 4,4'-diphenylmethane diisocyanate or dicyclohexylmethane diisocyanate as polyisocyanate (a1). Methods for adjusting the flow initiation temperature of component (A) to a low level include using a polyol with low crystallinity such as polyoxypropylene glycol as the polyol (a2), reducing the amount of chain extender (a2-1) used, and using a polyisocyanate with low crystallinity such as toluene diisocyanate or isophorone diisocyanate as the polyisocyanate (a1).

[0023] The flow initiation temperature of component (A) was determined by applying the urethane resin composition to release paper (coating thickness: 150 μm), drying in a hot air dryer at 70°C for 4 minutes and then at 120°C for 2 minutes to obtain a dried product, and then measuring the flow initiation temperature of this dried product using a flow tester "CFT-500A" manufactured by Shimadzu Corporation (using a die with an aperture diameter of 1 mm and a length of 1 mm, a load of 98 N, and a temperature rise rate of 3°C / min).

[0024] Specific examples of the component (A) include urethane resins made from polyisocyanate (a1) and polyol (a2).

[0025] [Polyisocyanate (a1)] Examples of the polyisocyanate (a1) that can be used include aromatic polyisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimidized diphenylmethane polyisocyanate; and aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dimer acid diisocyanate, and norbornene diisocyanate. These polyisocyanates may be used alone or in combination of two or more.

[0026] The proportion of the polyisocyanate (a1) used is preferably 5 to 60 mass%, more preferably 10 to 55 mass%, and even more preferably 15 to 50 mass%, relative to 100 mass% of the total of the polyisocyanate (a1) and the polyol (a2).

[0027] [Polyol (a2)] Examples of the polyol (a2) that can be used include polyether polyols, polyester polyols, polyacrylic polyols, polycarbonate polyols, polybutadiene polyols, etc. These polyols may be used alone or in combination of two or more.

[0028] From the viewpoint of the mechanical strength of the resulting coating, the number average molecular weight of the polyol (a2) is preferably 500 to 100,000, and more preferably 800 to 10,000. The number average molecular weight of the polyol (a2) is a value measured by gel permeation column chromatography (GPC).

[0029] Of the above, the polyol (a2) is preferably a polyether polyol (a21), a polycarbonate polyol (a22), or a polyester polyol (a23).

[0030] Polyether polyol (a21) Examples of the polyether polyol (a21) include polyethylene glycol, polypropylene glycol, polyethylene glycol-polytetramethylene glycol (block or random), polytetramethylene ether glycol, polyhexamethylene glycol, etc. Among these, polytetramethylene ether glycol is preferred.

[0031] Polycarbonate Polyol (a22) Commercially available polycarbonate polyol (a22) includes "ETERNACOLL UH-100" (manufactured by Ube Industries, Ltd.).

[0032] Examples of the polyester polyol (a23) include an esterification reaction product of a low-molecular-weight polyol with a polycarboxylic acid, a ring-opening polymerization product of a cyclic ester compound such as ε-caprolactone, and a polyester copolymer of the above-mentioned esterification reaction product or ring-opening polymerization product. Among these, a ring-opening polymerization product of a cyclic ester compound such as ε-caprolactone is preferred.

[0033] The proportion of polyol (a2) used is preferably 40 to 95 mass%, more preferably 45 to 90 mass%, and even more preferably 50 to 85 mass%, relative to 100 mass% of the total of polyisocyanate (a1) and polyol (a2), from the viewpoint of obtaining even better mechanical strength.

[0034] The component (A) may be a urethane resin made from polyisocyanate (a1), polyol (a2), chain extender (a3), and compound (a4) having an oxyethylene structure (excluding compounds corresponding to the above-mentioned (a1) to (a3)).

[0035] [Chain extender (a3)] As the chain extender (a3), a compound having a molecular weight of less than 500 (preferably in the range of 50 to 450) can be used. Specific examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, sorbitol, bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl chain extenders having a hydroxyl group, such as phenyl ether and trimethylolpropane; chain extenders having an amino group (—NH ) such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4′-dicyclohexylmethanediamine, 3,3′-dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, and hydrazine; ２ , —NH—, —N(-)-), etc. can be used. These chain extenders may be used alone or in combination of two or more. The molecular weight of the chain extender (a3) ​​is a value calculated from the chemical formula.

[0036] As the chain extender (a3), a chain extender having an amino group (hereinafter also referred to as an "amine chain extender") is preferred because it can easily extend the chain even at a relatively low temperature of 30°C or less, thereby reducing energy consumption during the reaction, because the introduction of a urea group provides even better texture and peel strength, and because it further facilitates high solids content of component (A), and it is more preferable to use an amine chain extender with a molecular weight in the range of 30 to 250. When two or more types of chain extender (a3) ​​are used in combination, the average molecular weight of each chain extender (a3) ​​is indicated, and it is sufficient that this average value falls within the preferred molecular weight range.

[0037] The proportion of chain extender (a3) ​​used is preferably 0.1 to 30 mass%, and more preferably 0.5 to 10 mass%, of the total mass of the raw materials constituting component (A), from the viewpoints of obtaining even better texture and peel strength and making it easier to achieve high solids content of component (A).

[0038] [Compound (a4) having an oxyethylene structure] As the compound (a4) having an oxyethylene structure, polyether polyols having an oxyethylene structure such as polyethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyethylene glycol dimethyl ether, etc. can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use polyethylene glycol and / or polyethylene glycol dimethyl ether, as this allows for easier control of hydrophilicity.

[0039] The proportion of the compound (a4) having an oxyethylene structure used is preferably 0.1 to 10 mass%, more preferably 0.2 to 10 mass%, and even more preferably 0.5 to 8 mass%, of the total mass of the raw materials constituting the component (A), from the viewpoint of obtaining even better mechanical strength.

[0040] The component (A) may be used alone or in combination of two or more thereof. The content of the component (A) is preferably 60 to 99 mass%, more preferably 65 to 98 mass%, and even more preferably 68 to 97 mass%, based on the total amount of solids constituting the urethane foam layer (ii).

[0041] [Method for producing urethane resin (A) having nonionic groups] Examples of methods for producing component (A) include a method comprising the steps of reacting polyisocyanate (a1), polyol (a2), and a compound (a4) having an oxyethylene structure in the absence of a solvent to obtain a urethane prepolymer (i) having an isocyanate group (hereinafter also referred to as the "prepolymer step"), subsequently dispersing the urethane prepolymer (i) in water (hereinafter also referred to as the "emulsification step"), and then reacting the urethane prepolymer (i) dispersed in water with a chain extender (a3) ​​to obtain a urethane resin (A) having a nonionic group (hereinafter also referred to as the "chain extension step").

[0042] "Prepolymerization Process" The prepolymerization process is preferably carried out in the absence of a solvent. In conventional technology, the prepolymerization process has generally been carried out in an organic solvent such as methyl ethyl ketone or acetone, but a desolvation process for distilling off the organic solvent is required after the emulsification process, which requires several production days in actual production sites. In addition, it is difficult to completely distill off the organic solvent in the desolvation process, and in many cases, a small amount of organic solvent remains, making it difficult to fully comply with environmental requirements. On the other hand, by producing a prepolymer in the absence of a solvent, a urethane resin completely free of organic solvent can be obtained, and the production process can also be made more labor-efficient.

[0043] In the prepolymerization step, the molar ratio of the sum of the hydroxyl groups in the polyol (a2) and the hydroxyl groups and amino groups in the compound (a4) having an oxyethylene structure to the isocyanate groups in the polyisocyanate (a1) [isocyanate groups / (hydroxyl groups and amino groups)] is preferably in the range of 1.1 to 3, more preferably in the range of 1.2 to 2, in order to obtain even better texture and peel strength.

[0044] The reaction in the prepolymerization step is carried out, for example, at 50 to 120° C. for 1 to 10 hours.

[0045] "Emulsification step" The emulsification step can be carried out using, for example, a reaction vessel equipped with an agitating blade; a kneader such as a kneader, a continuous kneader, a taper roll, a single-screw extruder, a twin-screw extruder, a triple-screw extruder, a universal mixer, a Plastomill, or a Bodeda-type kneader; a rotary dispersion mixer such as a homomixer, a static mixer, FILMICS, an Ebara Milder, a Clearmix, an Ultra-Turrax, a Cavitron, or a Biomixer; an ultrasonic dispersion device; or a device that has no moving parts and can mix by the flow of the fluid itself, such as an in-line mixer.

[0046] The water used in the emulsification step may be ion-exchanged water, distilled water, etc. These waters may be used alone or in combination of two or more.

[0047] The emulsification step is preferably carried out at a temperature at which water does not evaporate, for example, in the range of 10 to 90°C. The emulsification step can be carried out using the same equipment as in the prepolymer step.

[0048] "Chain extension step" The chain extension step is a step of increasing the molecular weight of the urethane prepolymer (i) by reacting the isocyanate groups of the urethane prepolymer (i) with the chain extender (a3) ​​to obtain component (A). From the viewpoint of productivity, the chain extension step is preferably carried out at a temperature of 50°C or less.

[0049] In the chain extension step, the molar ratio of the isocyanate groups in the urethane prepolymer (i) to the sum of the hydroxyl groups and amino groups in the chain extender (a3) ​​[(hydroxyl groups and amino groups) / isocyanate groups] is preferably in the range of 0.8 to 1.1, more preferably in the range of 0.9 to 1, in order to obtain even better texture and peel strength.

[0050] <<Optional Components>> The urethane foam layer (ii) may contain optional components other than the component (A). Examples of such optional components include surfactants, thickeners, leveling agents, pigments, antifoaming agents, crosslinking agents, emulsifiers, neutralizing agents, film-forming aids, urethanization catalysts, fillers, dyes, flame retardants, and antiblocking agents. These additives may be used alone or in combination of two or more. It is preferable that the component (A) is produced without substantially containing an organic solvent, but an organic solvent may be added as an additive. It is also preferable that the urethane foam layer (ii) does not contain a crosslinking agent. It is preferable that the urethane foam layer (ii) contains the component (A), a surfactant, and a thickener.

[0051] [Surfactant] The surfactant is preferably a surfactant having a hydrophobic moiety with 10 or more carbon atoms. Specifically, the surfactant is preferably a long-chain carboxylate, more preferably a long-chain carboxylate having 10 to 20 carbon atoms, and more preferably a long-chain carboxylate having 14 to 20 carbon atoms.

[0052] Specific examples of the surfactant include alkali metal salts of long-chain carboxylic acids, amine salts of long-chain carboxylic acids, and ammonium salts of long-chain carboxylic acids.

[0053] As the alkali metal used as a raw material for the alkali metal salt of a long-chain carboxylic acid, sodium and potassium are preferred.

[0054] Amines used as raw materials for long-chain carboxylic acid amine salts include monoamines, alkanolamines, polyamines, etc. Monoamines include primary amines, secondary amines, and tertiary amines. Specific examples of primary amines include ethylamine, n-propylamine, butylamine, 1-ethylbutylamine, 1,3-diaminopropane, and cyclohexylamine. Specific examples of secondary amines include diethylamine, di-n-propylamine, di-n-butylamine, 4,4'-diaminodiphenylamine, diethylenetriamine, tetraethylenepentamine, N-(2-aminoethyl)ethanolamine, and morpholine. Specific examples of tertiary amines include dimethylethylamine, diethylmethylamine, triethylamine, and tributylamine. Specific examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, diethylethanolamine, and propanolamine. Specific examples of polyamines include alkylene polyamines such as ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, propylene diamine, dipropylene triamine, tripropylene tetramine, tetrapropylene pentamine, pentapropylene hexamine, butylene diamine, dibutylene triamine, tributylene tetramine, tetrabutylene pentamine, and pentabtylene hexamine; N-alkyl ethylene diamines such as N-methyl ethylene diamine, N-ethyl ethylene diamine, and N-propyl ethylene diamine; N-alkenyl ethylene diamines such as N-vinyl ethylene diamine, N-propenyl ethylene diamine, and N-butenyl ethylene diamine; and N-alkyl or N-alkenyl alkylene polyamines such as N-alkyl diethylene triamine, N-alkenyl diethylene triamine, and N-alkyl triethylene tetramine.

[0055] Of the surfactants listed above, ammonium salts of long-chain carboxylic acids having 10 to 20 carbon atoms are preferred, ammonium salts of long-chain carboxylic acids having 14 to 20 carbon atoms are more preferred, and ammonium stearate is even more preferred.

[0056] The surfactant may be used alone or in combination of two or more. The content of the surfactant is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, and even more preferably 1 to 10% by mass, based on the total amount of solids constituting the urethane foam layer (ii).

[0057] [Thickener] Specific examples of thickeners include cellulose thickeners; acrylic thickeners; urethane thickeners; protein thickeners such as casein, sodium caseinate, and ammonium caseinate; polyvinyl thickeners such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinylbenzyl ether copolymers; polyether thickeners such as Pluronic (registered trademark) polyether, polyether dialkyl esters, polyether dialkyl ethers, and polyether epoxy-modified products; maleic anhydride thickeners such as vinyl methyl ether-maleic anhydride copolymers; and polyamide thickeners such as polyamidoamine salts.

[0058] The thickener may be used alone or in combination of two or more kinds. The content of the thickener is preferably 0.01 to 10% by mass, more preferably 0.05 to 8% by mass, and even more preferably 0.1 to 5% by mass, based on the total amount of solids constituting the urethane foam layer (ii).

[0059] <Other Layers> The laminate of the present embodiment may include layers other than the substrate (i) and the urethane foam layer (ii). Examples of the other layers include a surface layer (iii).

[0060] <<Surface layer>> The surface layer (iii) can be formed by a known method using a known material. The surface layer (iii) contains, for example, a solvent-based urethane resin, a water-based urethane resin, a silicone resin, a polypropylene resin, a polyester resin, etc. Among the above, the surface layer (iii) preferably contains a urethane resin (A) having a nonionic group, and more preferably contains the same urethane resin as the urethane resin contained in the above-mentioned urethane foam layer (ii).

[0061] If necessary, a surface treatment layer (iv) may be further provided on the surface layer (iii) for the purpose of improving scratch resistance, imparting gloss, etc. Examples of materials for forming the surface treatment layer (iv) include known aqueous urethane resins, solvent-based urethane resins, solventless urethane resins, aqueous acrylic resins, silicone resins, polypropylene resins, polyester resins, vinyl chloride resins, etc. These materials can be used alone or in combination of two or more.

[0062] (Method for Producing Laminate) Examples of methods for producing the laminate of this embodiment include: (X) a method of foaming the urethane resin composition to obtain a foamed liquid, applying the foamed liquid onto release paper, drying, and laminating the substrate (i); (Y) a method of foaming the urethane resin composition to obtain a foamed liquid, applying the foamed liquid onto a surface layer prepared on release paper, drying, and laminating the substrate (i); and (Z) a method of foaming the urethane resin composition to obtain a foamed liquid, applying the foamed liquid onto the substrate (i), drying, and, if necessary, laminating a surface layer (iii) prepared on release paper onto the foamed liquid.

[0063] Methods for foaming the urethane resin composition to obtain a foamed liquid include, for example, manual stirring and mechanical foaming using a mixer such as a mechanical mixer. Among these, the method using a mixer is preferred because a foamed liquid can be obtained easily. When a mixer is used, for example, a method of stirring at 500 to 3,000 rpm for 10 seconds to 10 minutes can be mentioned. In this case, in order to obtain a urethane foam layer (ii) with a good texture, it is preferable to increase the volume by 1.2 to 7 times, and more preferably 1.3 to 2 times, before and after foaming.

[0064] The foamed liquid thus obtained can be applied to the substrate (i) or the like by using, for example, a roll coater, a knife coater, a comma coater, an applicator, or the like.

[0065] The method for drying the coated material may be, for example, drying at a temperature of 60 to 130° C. for 30 seconds to 10 minutes.

[0066] (Synthetic Leather) The laminate of the above-described embodiment has quick peelability, a soft texture, and good processability, and is therefore particularly suitable for use as synthetic leather.

[0067] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0068] [Synthesis of Urethane Resin] <Synthesis of Urethane Resin (AX-1)> In the presence of 0.1 parts by mass of stannous octoate, 1,000 parts by mass of polyether polyol (Mitsubishi Chemical Corporation "PTMG2000", number average molecular weight: 2,000), 38 parts by mass of polyethylene glycol (NOF Corporation "PEG600", number average molecular weight: 600), and 262 parts by mass of dicyclohexylmethane diisocyanate were reacted at 100 ° C. until the NCO% reached 2.8% by mass to obtain a urethane prepolymer A1. 1,000 parts by mass of urethane prepolymer A1 heated to 70 ° C. was mixed with 200 parts by mass of a 20% by mass aqueous solution of sodium dodecylbenzenesulfonate (Dai-ichi Kogyo Seiyaku Co., Ltd. "Neogen S-20F") and 467 parts by mass of water to obtain an emulsion. Thereafter, an aqueous dilution of piperazine with an amino group content equivalent to 95% of the NCO groups was immediately added to extend the chain, and finally an aqueous dispersion of urethane resin (AX-1) with a non-volatile content of 55% by mass of the urethane resin was obtained. The urethane resin (AX-1) was applied to release paper (coating thickness 150 μm) and dried in a hot air dryer at 70 ° C. for 4 minutes, then at 120 ° C. for 2 minutes to obtain a dried product. This dried product was measured using a flow tester "CFT-500A" manufactured by Shimadzu Corporation (using a die with a diameter of 1 mm and a length of 1 mm, a load of 98 N, and a heating rate of 3 ° C. / min). The flow initiation temperature of the urethane resin (AX-1) was found to be 180 ° C.

[0069] <Synthesis of Urethane Resin (AX-2)> An aqueous dispersion of urethane resin (AX-2) was obtained in the same manner as in <Synthesis of Urethane Resin (AX-1)> above, except that the polyether polyol was changed to polycarbonate polyol ("ETERNACOLL UH-100" manufactured by Ube Industries, Ltd., number average molecular weight: 1,000). The flow initiation temperature of urethane resin (AX-2), measured in the same manner as above, was 175°C.

[0070] <Synthesis of Urethane Resin (AX-3)> An aqueous dispersion of urethane resin (AX-3) was obtained in the same manner as in <Synthesis of Urethane Resin (X-1)> above, except that the polyether polyol was changed to a polyester polyol ("Placcel 210" manufactured by Daicel Corporation, number average molecular weight: 1,000). The flow initiation temperature of urethane resin (AX-3), measured in the same manner as above, was 160°C.

[0071] <Synthesis of Urethane Resin (X-4)> In the presence of 0.1 parts by mass of stannous octoate, 1,000 parts by mass of polyether polyol ("PTMG2000" manufactured by Mitsubishi Chemical Corporation, number average molecular weight: 2,000), 38 parts by mass of polyethylene glycol ("PEG600" manufactured by NOF Corporation, number average molecular weight: 600), and 262 parts by mass of dicyclohexylmethane diisocyanate were reacted at 100 ° C. until the NCO% reached 2.8% by mass to obtain a urethane prepolymer A1. 1,000 parts by mass of urethane prepolymer A1 heated to 70 ° C. was mixed with 200 parts by mass of a 20% by mass aqueous solution of sodium dodecylbenzenesulfonate ("Neogen S-20F" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 467 parts by mass of water to obtain an emulsion. Immediately thereafter, an aqueous solution of piperazine having an amino group content corresponding to 75% of the NCO groups was added to cause chain elongation, thereby finally obtaining an aqueous dispersion of urethane resin (X-4) having a non-volatile content of 55% by mass. The flow initiation temperature of urethane resin (X-4), measured in the same manner as above, was 130°C.

[0072] <Preparation of Urethane Resin (X-5)> An ether-based PUD "Hydran WLS-120AR" (manufactured by DIC Corporation) was prepared as the urethane resin (X-5). The flow initiation temperature of the urethane resin (X-5), measured in the same manner as above, was 160°C.

[0073] <Synthesis of Urethane Resin (X-6) for Adhesive Layer> In the presence of 1,225 parts by mass of methyl ethyl ketone and 0.1 parts by mass of stannous octoate, 1,000 parts by mass of polyether polyol ("PTMG1000" manufactured by Mitsubishi Chemical Corporation, number average molecular weight: 1,000), 50 parts by mass of 2,2'-dimethylolpropionic acid, and 175 parts by mass of isophorone diisocyanate were reacted at 70 ° C. until the solution viscosity reached 20,000 mPa s, and then 3 parts by mass of methanol was added to terminate the reaction, yielding a methyl ethyl ketone solution of an anionic urethane resin. 61 parts by mass of polyoxyethylene distyrenated phenyl ether and 38 parts by mass of triethylamine were mixed with this urethane resin solution, and then 2,450 parts by mass of ion-exchanged water was added to cause phase inversion emulsification, yielding an emulsion in which the urethane resin was dispersed in water. Next, methyl ethyl ketone was distilled off from the emulsion to obtain an aqueous dispersion of urethane resin (X-6) with a nonvolatile content of 50% by mass.

[0074] [Method for Producing Laminate] <Laminate of Example 1> Preparation of Skin Layer Composition 100 g of an aqueous dispersion of urethane resin (AX-1), 2.0 g of a thickener (Borch Gel ALA; manufactured by Borchers), 0.1 g of a leveling agent (TEGO Flow 425; manufactured by Evonik), 0.1 g of an antifoaming agent (TEGO Twin 4000; manufactured by Evonik), and 10 g of a black pigment (DILAC HS-9550; manufactured by DIC Corporation) were stirred in a mechanical mixer at 2000 rpm for 2 minutes. The mixture was then defoamed using a vacuum defoamer to prepare Skin Layer Composition X1.

[0075] Preparation of Foam Layer Composition 100 g of an aqueous dispersion of urethane resin (AX-1), 2.0 g of a thickener (Borch Gel ALA; manufactured by Borchers), and 3.0 g of a surfactant (ammonium stearate) were stirred at 2,400 rpm using a mechanical mixer, and air was incorporated to prepare a foam layer composition X1 with a volume of 150% of the initial volume.

[0076] Preparation of Laminate of Example 1 After the surface layer composition X1 was coated onto release paper (EK-100D; manufactured by Lintech) using a knife coater (coating thickness: 100 μm), a surface layer was formed using a hot air dryer (drying conditions: 70°C x 2 min, 120°C x 2 min). The foam layer composition X1 was then coated thereon using a knife coater (coating thickness: 600 μm) to form a foam layer. Next, a substrate (thermoplastic urethane (TPU)) was pressure-bonded to the foam layer, thereby bonding the foam layer and the substrate together. The laminate (synthetic leather) of Example 1 was then obtained by drying at 120°C for 4 minutes. The dry density of the urethane foam layer in the laminate of Example 1 was 630 kg / m ３ The dry density of the urethane foam layer was calculated by subtracting the weight of the substrate per 10 cm square from the weight of the laminate of Example 1 per 10 cm square, and dividing the result by the thickness of the urethane foam layer (the same applies hereinafter).

[0077] <Laminate of Example 2> A laminate of Example 2 was produced in the same manner as in <Laminate of Example 1>, except that the aqueous dispersion of urethane resin (AX-1) in the surface layer composition X1 and the foam layer composition X1 was changed to an aqueous dispersion of urethane resin (AX-2). The dry density of the urethane foam layer in the laminate of Example 2 was 520 kg / m ３ It was.

[0078] <Laminate of Example 3> The laminate of Example 3 was produced by the same production method as <Laminate of Example 1>, except that the aqueous dispersion of urethane resin (AX-1) in the surface layer composition X1 and the foam layer composition X1 was changed to an aqueous dispersion of urethane resin (AX-3). The dry density of the urethane foam layer in the laminate of Example 3 was 780 kg / m ３ It was.

[0079] <Laminate of Comparative Example 1> A laminate of Comparative Example 1 was produced in the same manner as in <Laminate of Example 1>, except that the aqueous dispersion of urethane resin (AX-1) in the surface layer composition X1 and the foam layer composition X1 was changed to an aqueous dispersion of urethane resin (X-4). The dry density of the urethane foam layer in the laminate of Comparative Example 1 was 600 kg / m ３ It was.

[0080] <Laminate of Comparative Example 2> A laminate of Comparative Example 2 was produced by the same production method as in <Laminate of Example 1>, except that the aqueous dispersion of urethane resin (AX-1) in composition X1 for surface layer was changed to an aqueous dispersion of urethane resin (X-5), the aqueous dispersion of urethane resin (AX-1) in composition X1 for foam layer was changed to an aqueous dispersion of urethane resin (X-5), and 4.0 g of a crosslinking agent (Carbodilite SV-02; manufactured by Nisshinbo Chemical Inc.) was further blended.

[0081] <Laminate of Comparative Example 3> A laminate of Comparative Example 3 was produced in the same manner as in <Laminate of Example 1>, except that the aqueous dispersion of urethane resin (AX-1) in the composition X1 for surface layer and the composition X1 for foam layer was changed to an aqueous dispersion of urethane resin (X-5).

[0082] <Laminate of Comparative Example 4> Preparation of adhesive layer composition 100 g of the aqueous dispersion of urethane resin (X-6), 0.1 g of an antifoaming agent (Tego Foamex 800; manufactured by Evonik), and 1.0 g of a thickener (Borch Gel 0620; manufactured by Borchers) were stirred at 2000 rpm for 2 minutes using a mechanical mixer, and then defoamed using a vacuum defoamer to prepare an adhesive layer composition (X-6).

[0083] Preparation of Laminate of Comparative Example 4 After coating the surface layer composition X1 on release paper (EK-100D; manufactured by Lintech) using a knife coater (coating thickness: 100 μm), a surface layer was formed using a hot air dryer (drying conditions: 70°C x 2 min, 120°C x 2 min). Onto the surface layer, the foam layer composition X1 was coated using a knife coater (coating thickness: 600 μm) to form a foam layer (drying conditions: 70°C x 2 min, 120°C x 2 min). Next, the adhesive layer composition (X-6) was coated on the foam layer using a knife coater (coating thickness adjusted to a coating thickness of 50 μm when dried), and an adhesive layer was formed using a hot air dryer (drying conditions: 90°C x 3 min). A substrate (thermoplastic urethane (TPU)) was placed on the adhesive layer and bonded using a laminator at a temperature of 100°C, a pressure of 7.5 MPa, and a feed rate of 0.5 m / min to obtain a laminate of Comparative Example 4.

[0084] <Laminate of Comparative Example 5> After applying the surface layer composition X1 onto release paper (EK-100D; manufactured by Lintech) using a knife coater (coating thickness: 100 μm), a surface layer was formed using a hot air dryer (drying conditions: 70°C x 2 min, 120°C x 2 min). Onto the surface layer, the foam layer composition X1 was applied using a knife coater (coating thickness: 600 μm) to form a foam layer (drying conditions: 70°C x 2 min, 120°C x 2 min). Next, the adhesive layer composition (X-6) was applied onto the foam layer using a knife coater (coating thickness adjusted to a coating thickness of 50 μm when dried). A substrate (thermoplastic urethane (TPU)) was placed on the adhesive layer, and the two were laminated using a laminator at a temperature of 25°C, a pressure of 5 MPa, and a feed rate of 0.5 m / min. The adhesive layer was then dried in a hot air dryer (drying conditions: 120° C.×2 min) to obtain a laminate of Comparative Example 5.

[0085] [Evaluation of Peel Strength] A 2.5 cm wide hot melt tape (BW-2, manufactured by Sun Chemical Industry Co., Ltd.) was placed on the surface (surface of the skin layer) of the laminate and heated and pressed at 150°C for 30 seconds to adhere the hot melt tape. The laminate was cut along the width of the hot melt tape. The substrate and the hot melt tape were clamped with a zipper, and the substrate and foam layer of the cut laminate were peeled off, and the peel strength was measured using an autograph (manufactured by Shimadzu Corporation). The average value of the obtained data was calculated and converted to a 1 cm width, and the peel strength was evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: 3 kgf / cm or more B: 1.5 to less than 3 kgf / cm C: Less than 1.5 kgf / cm

[0086] [Evaluation of instant peelability] The peel strength of each laminate was measured immediately after production and after aging (heating at 60°C for a week), and the instant peelability was evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: The difference in peel strength is less than 0.5 kgf / cm. B: The difference in peel strength is 0.5 kgf / cm or more.

[0087] [Evaluation of hydrolysis resistance] The laminate of each example was left standing under humid heat conditions of 70°C and 95% RH for 3 weeks, and the hydrolysis resistance was evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: No abnormality in appearance. B: Change in gloss in appearance and / or stickiness to the touch.

[0088] [Evaluation of Processability] The laminate of each example was embossed. Next, the appearance of each laminate was compared, and observation was made with a scanning electron microscope (SEM) to determine whether the pattern was transferred more clearly. The processability was evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: The embossed pattern was transferred clearly, and it was confirmed by SEM observation that the pattern was sharp. B: The embossed pattern was not transferred clearly, and it was confirmed by SEM observation that the pattern was not sharp. Figure 1 shows an SEM image of the laminate of Example 1. Figure 2 shows an SEM image of the laminate of Comparative Example 2.

[0089] [Evaluation of texture] The texture of each laminate was evaluated by touch. A: Flexible and soft. B: Poor flexibility and hard.

[0090]

[0091]

[0092] As shown in Tables 1 and 2, the laminates of the Examples were superior to the laminates of the Comparative Examples in the evaluation results of peel strength, quick releasability, hydrolysis resistance, processability, and texture. Therefore, it was confirmed that the laminates of the Examples had quick releasability, a soft texture, and good processability.

[0093] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A laminate comprising a base material (i) and a urethane foam layer (ii), The urethane foam layer (ii) is in direct contact with the substrate (i), The urethane foam layer (ii) contains a urethane resin (A) having nonionic groups and a surfactant. The flow initiation temperature of the urethane resin (A) is above 130°C. The urethane resin (A) is made from polyisocyanate (a1), one or more polyols (a2) selected from the group consisting of polyether polyols, polycarbonate polyols, and polyester polyols, and a compound (a4) having an oxyethylene structure as essential raw materials. A laminate in which the proportion of the compound having the oxyethylene structure (a4) used is in the range of 0.1 to 10% by mass of the total mass of the raw materials constituting the urethane resin (A).

2. The laminate according to claim 1, wherein the flow initiation temperature of the urethane resin (A) is 150°C or higher.

3. The laminate according to claim 1, wherein the surfactant is a long-chain carboxylate.

4. The dry density of the aforementioned urethane foam layer (ii) is 200 to 1000 kg / m³. ３ The laminate according to claim 1 or 2.

5. A synthetic leather having the laminate described in claim 1 or 2.