Curable composition and synthetic leather

Abstract

To provide a curable composition capable of providing a synthetic leather good in low-temperature characteristics and excellent in physical property balance of flexibility (tactile sensation), chemical resistance, and heat resistance, and to provide a synthetic leather.SOLUTION: The curable composition contains a component (a): a polycarbonate polyol having a hydroxyl value of 40-75 mg KOH / g, a component (b): a polycarbonate polyol having a hydroxyl value of 100-280 mg KOH / g, a component (c): a polyether polyol, a component (d): a polyester polyol, and a component (e): a polyisocyanate having an average number of functional groups of 2-6 per molecule. The total amount of the component (a) and the component (b) is 30-70 mass% based on the total amount of all the polyol components in the composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a curable composition and synthetic leather.

Background Art

[0002] As conventional synthetic leather, there is a type obtained by applying a polyurethane resin solution polymerized using a polyether polyol such as polypropylene glycol or polytetramethylene glycol to a fibrous substrate or a film-forming plate and coagulating it in water. Although these synthetic leathers are excellent in flexibility and texture, they are easily decomposed by components such as sweat and have problems with durability. There is also synthetic leather obtained by using a polyurethane resin solution polymerized using a polyester polyol obtained by reacting a hydroxy compound and a dibasic acid and coagulating it. This synthetic leather has problems with hydrolysis resistance.

[0003] As synthetic leather for solving these problems, for example, Patent Document 1 discloses synthetic leather obtained from a polyurethane resin polymerized using polycarbonate diol. Specifically, Patent Document 1 discloses a porous sheet-like material in which a urethane composition comprising a polyurethane composed of polycarbonate diol, organic isocyanate and low molecular diol and a polyurethane composed of polyester-based diol, organic diisocyanate and low molecular diol is contained or joined in and / or on a fiber substrate.

[0004] Patent Document 2 discloses a porous sheet material obtained by a wet film forming method by applying a solution of a polyurethane resin composed of a polymer diol, an organic isocyanate, and, if necessary, a chain extender to a substrate. The porous sheet material is characterized in that the polymer diol is a mixed diol of a polycarbonate diol and a polyester diol, the polycarbonate diol is composed of 1,4-butanediol and one or more alkane diols having 4 to 6 carbon atoms, and the diol contains 50 to 90 mol% of 1,4-butanediol based on the total number of moles of the diol and is a copolymer polycarbonate diol having a number average molecular weight of 500 to 5000, and the solidification value of the polyurethane resin is 7 to 14.

[0005] Patent Document 3 discloses a synthetic leather surface coating layer using a polyurethane resin composed of an aliphatic oligocarbonate diol obtained by a transesterification reaction of an aliphatic diol and a dialkyl carbonate, a polyester polyol obtained by ring-opening addition polymerization of a cyclic ester compound using a compound having an active hydrogen group as an initiator, a polyisocyanate, and a chain extender.

[0006] Patent Document 4 discloses a porous sheet material obtained by reacting a polymer diol, an organic isocyanate, and a chain extender, the polymer diol being composed of a polycarbonate diol (a1) composed of an alkane diol having 4 to 6 carbon atoms and a polycarbonate diol (a2) composed of an alkane diol having 7 to 12 carbon atoms, both of the polycarbonate diols being copolymer polycarbonate diols, and the percentage mass% of (a1) with respect to the total mass of (a1) and (a2) being 10% or more and 80% or less, and obtained by wet coagulation.

[0007] Patent Document 5 discloses a surface layer material-forming composition for a fiber laminate composed of a main agent and a curing agent. The main agent is a polycarbonate diol obtained from 1,6-hexanediol and a low molecular carbonate, and the curing agent is a modified polyisocyanate (B1) of hexamethylene diisocyanate having a number average molecular weight of 350 to 500 and an average functional group number (f) of 2 ≤ f < 3 and an isocyanurate-modified polyisocyanate (B2) of hexamethylene diisocyanate having f ≥ 3, where (B1):(B2) = 50:50 to 95:5 (mass ratio), and a synthetic leather composed of a surface layer formed from the surface layer material-forming composition for a fiber laminate characterized by not containing an organic solvent in both the main agent and the curing agent and a fiber fabric is disclosed.

[0008] However, although the synthetic leather disclosed in Patent Documents 1 to 5 has hydrolysis resistance, its sweat resistance is not sufficient for applications that require high durability such as automobile seats.

[0009] Therefore, Patent Document 6 proposes a synthetic leather that uses a specific polycarbonate diol (a copolymerized polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol) in order to provide a synthetic leather that is excellent in the balance of physical properties such as sweat resistance and flexibility and does not crack or wrinkle during storage. However, for the polycarbonate diol described in Patent Document 6, it is necessary to use a large amount of an organic solvent during polyurethane polymerization, and further improvement is desired from the viewpoint of environmental load.

[0010] Patent Document 7 proposes a polyurethane for synthetic leather that is excellent in the physical property balance of flexibility, chemical resistance, low-temperature properties, heat resistance, and touch. Here, it is a polyurethane for synthetic leather obtained by reacting at least (a) a compound containing two or more isocyanate groups in one molecule, (b) a chain extender, and (c) a polycarbonate diol, wherein the (c) polycarbonate diol has a hydroxyl value of 20 mg-KOH / g or more and 45 mg-KOH / g or less, a glass transition temperature measured by a differential scanning calorimeter of -30°C or less, and an average carbon number of the dihydroxy compound obtained by hydrolyzing the polycarbonate diol of 3 or more and 5.5 or less. A polyurethane for synthetic leather characterized by this has been proposed. However, the polyurethane for synthetic leather disclosed in Patent Document 7 also requires the use of a large amount of organic solvent during polyurethane polymerization, which is not desirable in terms of environmental load.

[0011] In recent years, environmentally friendly polyurethanes have been proposed. For example, Patent Document 8 discloses a urethane prepolymer composition that is used by reacting a crosslinking agent with active hydrogen in its components to increase the molecular weight. It contains at least 20 to 80% by mass of a hydroxyl-terminated urethane prepolymer with a hydroxyl value of 10 to 100 mgKOH / g. Further, as a medium for the polymer, it contains 20 to 80% by mass of an oligomer having no urethane bond with a hydroxyl value of 20 to 400 mgKOH / g that can crosslink with the above crosslinking agent, and is substantially 100% non-volatile and liquid at a temperature of at least 30°C. A urethane prepolymer composition is characterized by this, and a two-component, solvent-free polyurethane for synthetic leather is proposed, which is characterized by containing 90 to 150 equivalent% of a polyisocyanate crosslinking agent with an NCO content of 5 to 35% by mass relative to the average hydroxyl value of this urethane prepolymer composition.

[0012] However, since the polyurethane prepolymer composition for synthetic leather disclosed in Patent Document 8 is solvent-free, ether-based polyols such as poly-THF or THF-neopentyl glycol copolymer polyol with a hydroxyl value of 20 to 400 mgKOH / g are used as oligomers without urethane bonds, resulting in a decrease in heat resistance and limited applications.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0014] An object of the present invention is to provide a curable composition capable of providing synthetic leather with good low-temperature characteristics and excellent physical property balance of flexibility (touch feeling), chemical resistance, and heat resistance, and synthetic leather using the same, in order to solve the above problems.

Means for Solving the Problems

[0015] As a result of intensive studies, the present inventors have found that a curable composition containing a polycarbonate diol, a polyether polyol, and a polyester polyol having a predetermined structure, or a predetermined isocyanate group-terminated prepolymer composition or a hydroxyl group-terminated prepolymer derived from these polyols, and a predetermined polyisocyanate, is excellent in the balance of physical properties such as flexibility (touch feeling), chemical resistance, low-temperature flexibility, and heat resistance, and can further provide an environmentally friendly synthetic leather that can be manufactured while suppressing the use of solvents, thus completing the present invention.

[0016] That is, the present invention includes the following aspects. <1> Component (a): A polycarbonate polyol having a hydroxyl value of 40 to 75 mgKOH / g, Component (b): A polycarbonate polyol having a hydroxyl value of 100 to 280 mgKOH / g, Component (c): A polyether polyol, Component (d): A polyester polyol, and Component (e): A polyisocyanate having an average functionality of 2 to 6 per molecule, and A curable composition in which the total amount of the component (a) and the component (b) is 30% to 70% by mass based on the total amount of all polyol components in the composition. <2> Component (f): A unit derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mgKOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mgKOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and a unit derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, and the curable composition according to <1> above. <3> Component (f): A polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, Component (a); a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, Component (b); a polyether polyol, Component (c); a polyester polyol, Component (d); units derived from one or more polyols selected from the group consisting of, and Component (e); units derived from a polyisocyanate having an average functionality of 2 to 6 per molecule, an isocyanate group-terminated prepolymer having these as constituent units, and Of the Component (a), the Component (b), the Component (c), and the Component (d), all components not included in the constituent units of the Component (f), and containing The total amount of the units derived from Component (a) and the units derived from Component (b) in the constituent units of the Component (f) and the total amount of the Component (a) and the Component (b) are 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. A curable composition. <4> Component (h): A hydroxyl group-terminated prepolymer containing units derived from one or more polyols selected from the group consisting of Component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, Component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, Component (c): a polyether polyol, Component (d): a polyester polyol, and Component (e): units derived from a polyisocyanate having an average functionality of 2 to 6 per molecule, and Of the Component (a), the Component (b), the Component (c), and the Component (d), all components not included in the constituent units of the Component (h), and the Component (e), and containing The total amount of the units derived from Component (a) and the units derived from Component (b) in the constituent units of the Component (h) and the total amount of the Component (a) and the Component (b) are 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. A curable composition. <5> Component (f): A polycarbonate polyol with a hydroxyl value of 40 to 75 mg KOH / g, Component (a): A polycarbonate polyol with a hydroxyl value of 100 to 280 mg KOH / g, Component (c): A polyether polyol, Component (d): A polyester polyol, one or more units derived from a polyol selected from the group consisting of, and Component (e): A unit derived from a polyisocyanate with an average functionality of 2 to 6 per molecule, an isocyanate group-terminated prepolymer having these as constituent units, and Component (h): A hydroxyl group-terminated prepolymer containing units derived from one or more polyols selected from the group consisting of Component (a): A polycarbonate polyol with a hydroxyl value of 40 to 75 mg KOH / g, Component (b): A polycarbonate polyol with a hydroxyl value of 100 to 280 mg KOH / g, Component (c): A polyether polyol, Component (d): A polyester polyol, and Component (e): A unit derived from a polyisocyanate with an average functionality of 2 to 6 per molecule, and Of the said Component (a), said Component (b), said Component (c), and said Component (d), all components not included in the constituent units of said Component (f) and said Component (h), Optionally said Component (e), Containing, The total amount of the units derived from Component (a) and the units derived from Component (b) in the constituent units of Component (f), the total amount of the units derived from Component (a) and the units derived from Component (b) in the constituent units of Component (h), and the total amount of Component (a) and Component (b) is 30% to 70% by mass with respect to the total amount of all polyol components in the composition. A curable composition. <6> The polycarbonate polyols of said Component (a) and said Component (b) contain a repeating unit represented by the following formula (1) and a terminal hydroxyl group, the curable composition according to any one of <1> to <5> above.

Chemical formula

Chemical formula

Advantages of the Invention

[0017] According to the curable composition of the present invention, it is possible to provide a curable composition capable of providing synthetic leather with good low-temperature characteristics and excellent physical property balance of flexibility (tactile sensation), chemical resistance, and heat resistance, and synthetic leather using the same.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0019] Hereinafter, the embodiments for carrying out the present invention (hereinafter abbreviated as "the present embodiments") will be described in detail. Note that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist thereof.

[0020] The curable composition of the present embodiment is Component (a): A polycarbonate polyol having a hydroxyl value of 40 to 75 mgKOH / g Component (b): A polycarbonate polyol having a hydroxyl value of 100 to 280 mgKOH / g Component (c): A polyether polyol Component (d): A polyester polyol Component (e): A polyisocyanate having an average functionality of 2 to 6 per molecule and includes, wherein the total amount of the component (a) and the component (b) is 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. The curable composition of the present embodiment, upon curing, that is, the component (a), the component (b), (c), (d), and, if necessary, a chain extender (component (g)) and the component (e) react to form a polyurethane. The polyurethane obtained by this reaction can be used as synthetic leather. Here, "synthetic leather" in this specification is a concept including artificial leather using a non-woven fabric as a base fabric in addition to synthetic leather using a knitted fabric or a woven fabric as a base fabric. The synthetic leather obtained by the curable composition of the present embodiment has good low-temperature characteristics and is excellent in the physical property balance of flexibility (touch feeling), chemical resistance, and heat resistance. Furthermore, the curable composition of the present embodiment can be an environmentally friendly curable composition that reduces the amount of solvent used or does not require the use of a solvent at all when producing such excellent synthetic leather.

[0021] In the curable composition of the present embodiment, the component (a), the component (b), the component (c), the component (d), the component (e), and, if necessary, the component (g) are used. The curable composition of this embodiment may be a mixture containing components (a), (b), (c), (d), (e), and optionally component (g) as the curable composition. An isocyanate group-terminated prepolymer composition obtained by selecting and reacting one or more of components (a), (b), (c), (d), and optionally component (g) may be prepared, and the isocyanate group-terminated prepolymer composition and a mixture containing one or more of components (a), (b), (c), (d), and optionally component (g) may be used as the curable composition. In this case, two or more isocyanate group-terminated prepolymers may be prepared and blended respectively. Further, the curable composition of this embodiment may be prepared by preparing a hydroxyl group-terminated prepolymer composition obtained by selecting and reacting one or more of components (a), (b), (c), (d), and optionally component (g), and using the hydroxyl group-terminated prepolymer composition and a mixture containing one or more of components (a), (b), (c), (d), and optionally component (g) as the curable composition. In this case, two or more hydroxyl group-terminated prepolymers may be prepared and blended respectively. The composition of this embodiment includes curable compositions in the following embodiments. The following embodiments can be obtained, for example, by the prepolymer method described later.

[0022] One of the compositions of this embodiment using an isocyanate group-terminated prepolymer is a curable composition containing the following isocyanate group-terminated prepolymer. Specifically, it is a curable composition containing an isocyanate group-terminated prepolymer containing "component (f): units derived from one or more polyols selected from the group consisting of component (a): polycarbonate polyol with a hydroxyl value of 40 to 75 mgKOH / g, component (b): polycarbonate polyol with a hydroxyl value of 100 to 280 mgKOH / g, component (c): polyether polyol, and component (d): polyester polyol" and "component (e): units derived from a polyisocyanate with an average functionality of 2 to 6 per molecule". The isocyanate group-terminated prepolymer can be obtained, for example, by previously reacting one or more polyols selected from the group consisting of components (a) to (d) with the polyisocyanate of component (e). As an example of such a curable composition containing an isocyanate group-terminated prepolymer, for example, a curable composition can be obtained that contains the isocyanate group-terminated prepolymer of component (f) and all components among the above components (a), (b), (c), and (d) that are not included in the structural unit of component (f). Here, "all components among the above components (a), (b), (c), and (d) that are not included in the structural unit of component (f)" means all of the remaining components not selected from the group consisting of the four components (a) to (d) with respect to the units derived from one or more polyols selected from the group consisting of components (a) to (d). For example, when component (f) has units derived from components (a) and (b), "all components among the above components (a), (b), (c), and (d) that are not included in the structural unit of component (f)" are components (c) and (d).

[0023] The isocyanate group-terminated prepolymer composition of component (f) may contain unreacted components (a), (b), (c), and (d).

[0024] As one of the compositions of this embodiment using a hydroxyl group-terminated prepolymer, a curable composition containing the following hydroxyl group-terminated prepolymer can be mentioned. Specifically, component (h): "units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mgKOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mgKOH / g, component (c): a polyether polyol, and component (d): a polyester polyol" and "units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule" and The isocyanate group-terminated prepolymer of the component (f) and / or the component (e), and Among the component (a), the component (b), the component (c), and the component (d), all components not included in the structural unit of the component (h) (when the component (f) is included, all components not included in the structural units of the (f) and the component (h)), and A curable composition containing the same. The hydroxyl group-terminated prepolymer can be obtained, for example, by previously reacting one or more polyols selected from the group consisting of components (a) to (d) with the polyisocyanate of component (e). The hydroxyl group-terminated prepolymer composition of component (h) may contain unreacted components (a), (b), (c), and (d). Note that "all components among the component (a), the component (b), the component (c), and the component (d) that are not included in the structural unit of the component (h)" and "all components among the component (a), the component (b), the component (c), and the component (d) that are not included in the structural units of the component (f) and (h)" mean, as described above, all of the remaining components not selected from the group consisting of the four components (a) to (d) that are derived from units of one or more polyols selected from the group consisting of components (a) to (d) included as the structural unit of component (h) (or components (f) and component (h)). For example, when component (h) (or components (f) and (h)) has units derived from components (a) and (b), "all components among the component (a), the component (b), the component (c), and the component (d) that are not included in the structural unit of the component (h) (or components (f) and (h))" are components (c) and (d).

[0025] The synthetic leather obtained from the curable composition of the present embodiment has good low-temperature characteristics and is excellent in the physical property balance of flexibility (touch feeling), chemical resistance, and heat resistance. Further, the synthetic leather obtained from the curable composition of the present embodiment is an environment-friendly synthetic leather that can be manufactured while suppressing the use of solvents.

[0026] <Component (a) and Component (b)> In the curable composition of the present embodiment, at least two types of polycarbonate polyols (component (a) and component (b)) with different hydroxyl values are used. Two types of polycarbonate diols with different hydroxyl values have high solubility in solvents regardless of the amount of hydroxyl groups, so it is considered that synthetic leather can be manufactured while suppressing the amount of solvent used compared to other polycarbonate polyols. In addition, it is considered to have the advantages of polycarbonate polyols with a low hydroxyl value (high molecular weight) and polycarbonate diols with a high hydroxyl value (low molecular weight) well balanced, and to be excellent in the physical property balance of flexibility (tactile feel), chemical resistance, low temperature characteristics, and heat resistance.

[0027] One of the polycarbonate polyols used in the curable composition of the present embodiment is a polycarbonate polyol (component (a)) having a hydroxyl value of 40 to 75 mgKOH / g. The hydroxyl value of component (a) is preferably 45 to 70 mgKOH / g, more preferably 50 to 65 mgKOH / g. When the hydroxyl value of component (a) is 40 mgKOH / g or more, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced. In addition, when the hydroxyl value of component (a) is 75 mgKOH / g or less, the flexibility (tactile feel) and low temperature characteristics of the resulting synthetic leather tend to increase.

[0028] Moreover, the melt viscosity of component (a) at 50°C is preferably 3000 to 25000 mPa·s, more preferably 5000 to 18000 mPa·s, and even more preferably 7000 to 16000 mPa·s. When the melt viscosity of component (a) at 50°C is 3000 mPa·s or more, the flexibility and low temperature characteristics of the resulting synthetic leather tend to increase. In addition, when the melt viscosity of component (a) at 50°C is 25000 mPa·s or less, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced.

[0029] One of the polycarbonate polyols used in the curable composition of this embodiment is a polycarbonate polyol (component (b)) having a hydroxyl value of 100 to 280 mgKOH / g. The hydroxyl value of component (b) is preferably 130 to 250 mgKOH / g, more preferably 160 to 240 mgKOH / g. When the hydroxyl value of component (b) is 100 mgKOH / g or more, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced. Further, when the hydroxyl value of component (b) is 280 mgKOH / g or less, the resulting synthetic leather is excellent in flexibility (touch feeling) and low-temperature properties.

[0030] The melt viscosity of component (b) at 50°C is preferably 150 to 600 mPa·s, more preferably 180 to 500 mPa·s, and still more preferably 200 to 400 mPa·s. When the melt viscosity of component (b) at 50°C is 150 mPa·s or more, the resulting synthetic leather tends to be excellent in flexibility (touch feeling) and low-temperature properties. Further, when the melt viscosity of component (b) at 50°C is 600 mPa·s or less, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced.

[0031] The average number of hydroxyl groups in one molecule of component (a) and component (b) is preferably 1.7 to 3.5, more preferably 1.8 to 3.0, and still more preferably 2.0 to 2.5, respectively.

[0032] Component (a) and component (b) are preferably polycarbonate polyols each having a repeating unit represented by formula (1) and a terminal hydroxyl group. In this embodiment, the structure of the polycarbonate polyol of component (a) and the structure of the polycarbonate polyol of component (b) may be the same or different.

[0033] [Chemical formula] (In formula (1), R1 represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.)

[0034] In components (a) and (b), in addition to the structure of the polycarbonate polyol, an ether structure and an ester structure may be included. When components (a) and (b) have other structures such as an ether structure or an ester structure, the content of the repeating unit represented by formula (1) in each of components (a) or (b) is preferably 50 mol% or more, and more preferably 70 mol% or more.

[0035] Components (a) and (b) are not particularly limited. For example, a bifunctional diol compound, optionally a polyhydric alcohol having three or more functional groups, and a carbonic acid ester can be used as raw materials, and can be synthesized, for example, by a transesterification reaction described in "Polymer Reviews, Volume 9, pages 9-20", etc.

[0036] The bifunctional diol compound used in the transesterification reaction is not particularly limited, and examples thereof include diols having a divalent aliphatic or alicyclic hydrocarbon skeleton having 2 to 15 carbon atoms. Specific examples of the bifunctional diol compound include ethylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2-methyl-1,8-octanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 2-isopropyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, etc. These bifunctional diol compounds may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining a curable composition excellent in flexibility (touch), chemical resistance, low-temperature properties, and heat resistance, an alkylene diol having 3 to 10 carbon atoms is preferable, and an alkylene diol having 4 to 6 carbon atoms is more preferable. Further, it is preferable to use two or more kinds of alkylene diols in combination.

[0037] Since the carbon number of the bifunctional diol compound is 2 or more, the viscosity of the curable composition can be suppressed low, and in addition to reducing the amount of the organic solvent used, the flexibility and low-temperature properties of the obtained synthetic leather tend to increase. Since the carbon number of the bifunctional diol compound is 15 or less, the chemical resistance of the obtained synthetic leather tends to be excellent.

[0038] By using two or more kinds of bifunctional diol compounds in combination, the regularity of the structural units of the obtained polycarbonate diol decreases, and the crystallinity decreases, so that a polycarbonate diol that is liquid at room temperature (25 ° C) tends to be obtained. As a result, the amount of the organic solvent used tends to be suppressed. Further, in the present embodiment, as raw materials for the component (a) and the component (b), in addition to the bifunctional diol, a polyhydric alcohol compound having three or more functional groups can be used as necessary. The polyhydric alcohol compound is not particularly limited, and examples thereof include trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, glycerin and the like. By using a polyhydric alcohol, the average number of hydroxyl groups per molecule in the component (a) and the component (b) can be easily adjusted to be in the range of 1.7 to 3.5.

[0039] In the present embodiment, it is preferable that 50 mol% or more of the repeating units represented by the formula (1) contain at least two repeating units selected from the formula (2), the formula (3), and the formula (4). The content of the repeating units of the formula (2), the formula (3), and the formula (4) is preferably 70 mol% or more, and more preferably 80 mol% or more.

[0040]

Chemical formula

[0041] Among the repeating units represented by formula (1), when at least two repeating units selected from formula (2), formula (3), and formula (4) are 50 mol% or more, in addition to the resulting synthetic leather having excellent flexibility (feel), chemical resistance, low-temperature properties, and heat resistance, there is a tendency to reduce the amount of the inert organic solvent used. Among the repeating units represented by formula (1), the upper limit of the ratio (mol%) of at least two repeating units selected from formula (2), formula (3), and formula (4) is not particularly limited, but is usually 100 mol% or less.

[0042] In the present embodiment, when two repeating units are selected from formula (2), formula (3), and formula (4), the ratio of the two repeating units (hereinafter also referred to as "copolymerization ratio") is 90:10 to 10:90 in molar ratio, preferably 70:30 to 30:70, more preferably 60:40 to 40:60. When the copolymerization ratio is within the above range, the crystallinity of the polycarbonate diol decreases, and there is a tendency to obtain a synthetic leather having high flexibility, good low-temperature properties, and feel. Furthermore, if the copolymerization ratio is within this range, there is a tendency to reduce the amount of the inert organic solvent used.

[0043] In this embodiment, when three types of repeating units of formula (2), formula (3), and formula (4) are selected, the proportions of the structural units of formula (2), formula (3), and formula (4) are preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably 20 mol% or more, respectively, when the total of the three types of repeating units of formula (2), formula (3), and formula (4) is 100 mol%. When the proportion of each of the three types of repeating units of formula (2), formula (3), and formula (4) in the total of the three types of repeating units of formula (2), formula (3), and formula (4) is within the above range, the crystallinity of the polycarbonate diol decreases, and a synthetic leather having high flexibility, good low-temperature characteristics, and feel tends to be obtained. Further, when the proportion of each of the three types of repeating units of formula (2), formula (3), and formula (4) is within the above range, the amount of the inert organic solvent used can tend to be reduced.

[0044] Examples of the carbonic ester that can be used for the synthesis of component (a) and component (b) include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate; diaryl carbonates such as diphenyl carbonate; alkylene carbonates such as ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate; and the like. From the viewpoints of ease of availability and ease of setting the polymerization reaction conditions, it is preferable to use dimethyl carbonate, diethyl carbonate, diphenyl carbonate, or ethylene carbonate as the carbonic ester.

[0045] In the production of component (a) and component (b), a catalyst may or may not be added. When adding a catalyst, it can be freely selected from the catalysts used in ordinary transesterification reactions. As the catalyst, for example, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, etc., as well as metal salts thereof, metal alkoxides thereof, and organic compounds containing the metal are used. Among the above catalysts, organic compounds containing titanium, tin, or lead are preferred. Also, the amount of the catalyst used is usually 0.00001 to 0.1% of the mass of the bifunctional diol compound which is the raw material and the trifunctional or higher polyhydric alcohol which may be contained as necessary.

[0046] As described above, the production method of component (a) and component (b) in the present embodiment can be synthesized by a transesterification reaction using a bifunctional diol compound, a trifunctional or higher polyhydric alcohol as necessary, and a carbonic ester as raw materials. More specifically, the transesterification reaction is carried out according to the following procedure. First, one or more bifunctional diol compounds in a predetermined ratio, one or more trifunctional or higher polyhydric alcohols in a predetermined ratio as necessary, and one or more carbonic esters in a predetermined ratio are mixed, and the transesterification reaction is carried out at a temperature of 100 to 200 ° C, preferably 140 to 180 ° C, in the absence or presence of a transesterification catalyst under normal pressure or reduced pressure. Subsequently, by distilling off the alcohol derived from the carbonic ester generated during the reaction, a polycarbonate diol having a molecular weight of about 300 to 500 g / mol is obtained. Next, under reduced pressure, at 130 to 230 ° C, preferably 150 to 200 ° C, the unreacted carbonic ester, bifunctional diol, and optionally contained trifunctional or higher polyhydric alcohol are distilled off, and components (a) and (b) having a desired hydroxyl value can be obtained by a condensation reaction. The composition of component (a) and component (b) and the average number of hydroxyl groups per molecule can be adjusted by controlling the charging ratio of each component at the beginning, the amount of each raw material distilled off during production, and the amount of the reaction product.

[0047] As component (a) and component (b) used in this embodiment, commercially available products may be used. Although not particularly limited, for example, those manufactured by Asahi Kasei Corporation; trade name "Duranol" series, those manufactured by Ube Industries, Ltd.; trade name "ETERNACOLL" series, those manufactured by Kuraray Co., Ltd.; trade name "Kuraray Polyol C" series, "Kuraray Polyol F" series, those manufactured by Daicel Corporation; trade name, "Placcel" series, those manufactured by Tosoh Corporation; trade name "Niporan" series, those manufactured by Perstop Co., Ltd.; "Oximer" series, those manufactured by Mitsubishi Chemical Corporation; trade name "BENEBiOL" series, etc. can be mentioned. These may be used alone or in any combination of two or more.

[0048] <Component (c)> In the curable composition of this embodiment, component (c): polyether polyol is used. By using polyether polyol, it can contribute to the flexibility and low-temperature characteristics of synthetic leather, and also contribute to the improvement of heat and humidity resistance.

[0049] The polyether polyol used in the curable composition of this embodiment is not particularly limited, but it is preferably a polyether polyol having a hydroxyl value of 40 to 75 mgKOH / g. The hydroxyl value of component (c) is preferably 45 to 70 mgKOH / g, more preferably 50 to 65 mgKOH / g. When the hydroxyl value of component (c) is 40 mgKOH / g or more, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced. Also, when the hydroxyl value of component (c) is 75 mgKOH / g or less, the flexibility (touch feeling) and low-temperature characteristics of the resulting synthetic leather tend to be further enhanced.

[0050] Component (c) preferably has a melt viscosity at 50°C of 200 to 2000 mPa·s, more preferably 300 to 1500 mPa·s, and even more preferably 500 to 1000 mPa·s. When the melt viscosity of component (c) at 50°C is 200 mPa·s or more, the flexibility and low-temperature properties of the resulting synthetic leather tend to be enhanced. Also, when the melt viscosity of component (c) at 50°C is 2000 mPa·s or less, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced.

[0051] The average number of hydroxyl groups in one molecule of component (c) is preferably 1.7 to 3.5, more preferably 1.8 to 3.0, and even more preferably 2.0 to 2.5, respectively.

[0052] The number of carbon atoms in the main chain of component (c) is not particularly limited, but from the viewpoint of easy availability, the number of carbon atoms in the main chain is preferably 2 to 4. Further, from the viewpoint of suppressing the decrease in water resistance due to water absorption of the polyurethane, it is preferable that the oxygen atom content is low, and the number of carbon atoms in the main chain is more preferably 3 to 4. Only one type of polyether polyol may be used, or two or more types may be used in combination. Specific examples of the polyether polyol are not particularly limited, and include, for example, polytetramethylene ether glycol, polytetramethylene ether glycol having an alkyl side chain, polytrimethylene ether glycol, polypropylene glycol, polyethylene glycol, and copolymers of two or more of these; random copolymers or block copolymers of ethylene oxide and propylene oxide, or random copolymers or block copolymers of ethylene oxide and butylene oxide, etc. Among them, polytetramethylene ether glycol, polytrimethylene ether glycol, etc. are preferable.

[0053] As the component (c) used in this embodiment, commercially available products may be used. The commercially available products are not particularly limited. For example, those manufactured by Mitsubishi Chemical; trade names "polytetramethylene ether glycol (PTMG)", "BioPTMG", manufactured by Invista; trade name "Terathane" series, manufactured by BASF; "PolyTHF" series, manufactured by Hodogaya Chemical; "PTG" series, manufactured by Lyondell Basel; "Polymeg" series, manufactured by Bayer; "Arcol" series, manufactured by SK Chemicals; "EcoTrion" series, manufactured by NOF Corporation; "Pronon" series, manufactured by Sanyo Chemical Industries; "Sunnex" series, manufactured by ADEKA; "Adekapolyglycol" series, manufactured by DIC; "Polyrite" series, etc. are available.

[0054] Examples of the component (c) include those obtained by using any of the following methods (1) to (2), etc. (1) Polyether polyol or polytetramethylene ether glycol obtained by adding a single or a mixture of alkylene oxides to a single or a mixture of polyhydric alcohols (2) Polyether polyol obtained by reacting a polyfunctional compound with an alkylene oxide Examples of the polyhydric alcohol include glycerin and propylene glycol. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

[0055] In this embodiment, as a starting material for the component (c), in addition to the bifunctional diol, a polyhydric alcohol compound having three or more functional groups can be used as needed. The polyhydric alcohol compound is not particularly limited. For example, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, glycerin, etc. can be mentioned. By using the polyhydric alcohol, the average number of hydroxyl groups in one molecule in the component (c) tends to be easily adjusted to the range of 1.7 to 3.5.

[0056] <Component (d)> In the curable composition of the present embodiment, component (d): polyester polyol is used. By using an ester polyol, it contributes to improving the adhesive strength between the layers of synthetic leather and tends to improve the adhesiveness with polyester fibers, which are typical base fabrics. In addition, a balance of physical properties such as flexibility (touch feeling), chemical resistance, low-temperature properties, and heat resistance can be maintained.

[0057] Component (d) used in the curable composition of the present embodiment is not particularly limited, but it is preferably a polyester polyol having a hydroxyl value of 40 to 75 mgKOH / g. The hydroxyl value of component (d) is preferably 45 to 70 mgKOH / g, more preferably 50 to 65 mgKOH / g. When the hydroxyl value of component (d) is 40 mgKOH / g or more, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced. Also, when the hydroxyl value of component (d) is 75 mgKOH / g or less, the flexibility (touch feeling) and low-temperature properties of the resulting synthetic leather tend to be enhanced. Furthermore, it is preferable that the hydroxyl value of component (c): polyether polyol and the hydroxyl value of the said component (d): polyester polyol are each 40 to 75 mgKOH / g.

[0058] The melt viscosity of component (d) at 50°C is preferably 500 to 7000 mPa·s, more preferably 800 to 5000 mPa·s, still more preferably 1000 to 4000 mPa·s. When the melt viscosity of component (d) at 50°C is 500 mPa·s or more, the flexibility and low-temperature properties of the resulting synthetic leather tend to be enhanced. Also, when the melt viscosity of component (d) at 50°C is 7000 mPa·s or less, the viscosity of the resulting curable composition can be kept low, and the amount of organic solvent used can be reduced.

[0059] The average number of hydroxyl groups in one molecule of component (d) is preferably 1.7 to 3.5, more preferably 1.8 to 3.0, still more preferably 2.0 to 2.5, respectively.

[0060] Component (d) is not particularly limited, and examples thereof include polyester polyols of any of the following (1) or (2). (1) A polyester polyol resin obtained by a condensation reaction of a dibasic acid alone or a mixture of two or more kinds thereof with a bifunctional diol compound and / or a mixture of a polyhydric alcohol alone or two or more kinds thereof (2) A polycaprolactone polyol obtained by ring-opening polymerization of ε-caprolactone with a bifunctional diol compound and / or a polyhydric alcohol The dibasic acid is not particularly limited, and examples thereof include carboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. The bifunctional diol compound is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2-methyl-1,8-octanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 2-isopropyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, etc. The polyhydric alcohol compound is not particularly limited, and examples thereof include trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, glycerin, etc.

[0061] The number of carbon atoms in the main chain of component (d) is not particularly limited. However, from the perspective of availability, the number of carbon atoms in the main chain is preferably 2 to 9 for those derived from bifunctional diol compounds and polyhydric alcohols, and preferably 4 to 10 for those derived from dibasic acids. Furthermore, from the perspective of suppressing the decrease in water resistance due to water absorption of the polyurethane, it is preferable that the content of carbon atoms is higher. More preferably, it is 4 to 6 for those derived from bifunctional diol compounds and polyhydric alcohols, and more preferably 4 to 10 for those derived from dibasic acids. Only one type of polyester polyol may be used, or two or more types may be used in combination. Specific examples of component (d) are not particularly limited. For example, polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, polypentylene adipate diol, polyhexylene adipate diol, polyethylene butylene adipate diol, polyhexamethylene isophthalate adipate diol, polyethylene succinate diol, polybutylene succinate diol, polyethylene sebacate diol, polybutylene sebacate diol, poly(3-methyl-1,5-pentylene adipate) diol, poly-γ-butyrolactone diol, poly-δ-valerolactone diol, poly-ε-caprolactone diol, the polycondensate of 1,6-hexanediol and dimer acid, castor oil-modified polyol, etc. can be mentioned. Among them, preferably, polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, polypentylene adipate diol, polyhexylene adipate diol, poly(3-methyl-1,5-pentylene adipate) diol, poly-ε-caprolactone diol, and more preferably polyhexylene adipate diol, poly(3-methyl-1,5-pentylene adipate) diol, poly-ε-caprolactone diol.

[0062] As described above, the production method of component (d) in this embodiment can be synthesized by a transesterification reaction using a bifunctional diol compound, a polyhydric alcohol having three or more functions as needed, and a dibasic acid as raw materials. More specifically, the transesterification reaction is carried out according to the following procedure. First, one or more difunctional diol compounds in a predetermined ratio, one or more polyhydric alcohols with three or more functional groups in a predetermined ratio as required, and one or more dibasic acids in a predetermined ratio are mixed, and the transesterification reaction is carried out at a temperature of 100 to 280 ° C, preferably 140 to 220 ° C, in the absence or presence of a transesterification catalyst under normal pressure or reduced pressure. Subsequently, the component (d) with a desired hydroxyl value can be obtained by a condensation reaction for distilling off the water generated during the reaction. The composition of component (d) and the average number of hydroxyl groups in one molecule can be adjusted by controlling the charging ratio of each initial component, the amount of each raw material distilled off during production, and the amount of the reaction product.

[0063] As the component (d) used in this embodiment, commercially available products may be used. The commercially available products are not particularly limited. For example, those manufactured by Kyowa Chemical Industry Co., Ltd.; trade name "Kyowapol" series, manufactured by Kuraray Co., Ltd.; trade name "Kuraray Polyol" series, manufactured by Daicel Corporation; trade name "Placcel" series, manufactured by DIC Corporation; trade name "Polylite" series, manufactured by Tosoh Corporation; trade name "Nipporan" series, manufactured by Bayer; "Desmophen" series, etc.

[0064] In this embodiment, the preferred mass ratio of component (a) to component (b) is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total 100% by mass of component (a) and component (b), in terms of the proportion of component (a) contained therein. When the proportion of component (a) is 20% by mass or more, the flexibility (touch feeling) and low-temperature characteristics of the obtained synthetic leather tend to be more excellent. When the proportion of component (a) is 80% by mass or less, the viscosity of the obtained curable composition can be kept low, and the amount of the organic solvent used can be reduced.

[0065] In the curable composition of the present embodiment, polyols of components (a), (b), (c), and (d) are used, but polyols other than components (a), (b), (c), and (d) may be used in combination as necessary. Here, the polyols other than components (a), (b), (c), and (d) are not particularly limited as long as they are those used in the production of ordinary polyurethanes. Examples include acrylic polyols, polyolefin polyols, castor oil polyols, polycarbonate polyols other than component (a) and component (b), and the like.

[0066] In the curable composition of the present embodiment, the total amount of the above-mentioned component (a) and component (b) is 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. The mass ratio of component (a) and component (b) to the combined mass of component (a) and component (b) and other polyols (the total amount of all polyol components in the composition) is more preferably 40% by mass or more. When the mass ratio of component (a) and component (b) is 30% by mass or more, when made into synthetic leather, the balance of flexibility (feel), chemical resistance, low-temperature characteristics, and heat resistance tends to be excellent. On the other hand, adding other polyols contributes to the effect of reducing the viscosity of the curable composition of the present embodiment and can be used in combination within a range that does not impair the performance. When the curable composition of the present embodiment contains the prepolymer of component (f) or the prepolymer of component (h) described below, it is as follows. i) When containing the prepolymer of component (f) The total amount of the units derived from component (a) and the units derived from component (b) in the structural units of component (f), and the total amount of component (a) and component (b), is 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. ii) When containing the prepolymer of component (h) The total amount of the units derived from component (a) and the units derived from component (b) in the structural units of component (h), and the total amount of component (a) and component (b), is 30% by mass to 70% by mass with respect to the total amount of all polyol components in the composition. iii) When containing the prepolymer of component (f) and the prepolymer of component (h) The total amount of the units derived from component (a) and the units derived from component (b) in the structural unit of component (f), the total amount of the units derived from component (a) and the units derived from component (b) in the structural unit of component (h), and the total amount of component (a) and component (b) is 30% to 70% by mass based on the total amount of all polyol components in the composition. The total amount of the units derived from component (a) or component (b) in the prepolymer can be calculated, for example, by a method of measuring with an infrared spectrophotometer (IR), a method of measuring with a nuclear magnetic resonance apparatus after dissolving in a heavy solvent (1H-NMR, 13C-NMR), a method of analyzing the composition of the polyol described later, gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), and one of known analysis methods such as a matrix-assisted laser desorption / ionization time-of-flight mass spectrometer MALDI-TOFMS, or a combination thereof.

[0067] <Component (e)> In the curable composition of the present embodiment, a polyisocyanate (component (e)) having an average functionality of 2 to 6 per molecule is used. Examples of component (e) in the present embodiment include aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, diphenylmethane-4,4'-diisocyanate (MDI), naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), polymethylene polyphenylene polyisocyanate (polymeric MDI, PMDI), polycarbodiimide-modified diphenylmethane diisocyanate; aromatic aliphatic diisocyanates such as xylylene diisocyanate (XDI), phenylene diisocyanate; aliphatic diisocyanates such as 4,4'-methylenebis(cyclohexyl diisocyanate) (hydrogenated (also referred to as hydrogenated) MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane diisocyanate (hydrogenated XDI), and the like.

[0068] As the component (e) used in this embodiment, a polyisocyanate having an average of 2.1 or more isocyanate groups in one molecule can also be used. Examples of the polyisocyanate having an average of 2.1 or more isocyanate groups in one molecule include aromatic polyisocyanates such as crude MDI and crude TDI; derivatives of aliphatic isocyanates such as HDI and IPDI, specifically diisocyanate derivatives such as biuret, allophanate, uretdione, and isocyanurate; and polyhydric alcohol adduct types can be used. The polyisocyanate having 2.1 or more isocyanate groups in one molecule is not particularly limited. For example, Sumidur 44S, 44V70 (both manufactured by Sumitomo Bayer Urethane), Desmodur HL which is a copolymer of TDI and HDI (manufactured by Sumitomo Bayer Urethane), various Duranates manufactured by Asahi Kasei Corporation, namely Duranate 24A-100, Duranate 22A-75PX, Duranate 18H-70B, Duranate 21S-75E, Duranate THA-100, Duranate TPA-100, Duranate TKA-100, Duranate TLA-100, Duranate TUL-100, Duranate MFA-75X, Duranate TSA-100, Duranate TSS-100, Duranate TSE-100, Duranate D-101, Duranate D-201, Duranate P-301-75E, Duranate E-402-90T, Duranate E-402-90T, Duranate E-405-80T, Duranate ME20-100, Duranate 17B-60PX, Duranate TPA-B80X, Duranate MF-B60X, Duranate E-402-B80T, Duranate ME20-B80S, Duranate WB40-100, Duranate WB40-80D, Duranate WT20-100, Duranate WT30-100, etc. are available.

[0069] Furthermore, as the component (e), a so-called blocked isocyanate blocked with a known blocking agent such as a lower alcohol such as butanol or 2-ethylhexanol, methyl ethyl ketone oxime, lactams, phenols, imidazoles, or an active methylene compound can also be used.

[0070] When the amount of component (e) used is expressed as [isocyanate equivalent of component (e)] / [total hydroxyl equivalent of components (a), (b), (c), and (d)], it is preferably adjusted to be 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1. By having [isocyanate equivalent of component (e)] / [total hydroxyl equivalent of components (a), (b), (c), and (d)] be 0.7 or more and 1.3 or less, the molecular weight of the resulting polyurethane can be appropriately controlled, and it tends to have excellent mechanical properties such as strength, elongation, and abrasion resistance.

[0071] It is preferable to use an aromatic polyisocyanate such as MDI as component (e). By using an aromatic polyisocyanate, a synthetic leather with excellent mechanical properties tends to be obtained. When an aromatic polyisocyanate such as MDI is used as component (e) in the curable composition, the curable composition can be suitably used mainly as an adhesive between the base fabric and the surface layer of the synthetic leather. When an aliphatic polyisocyanate such as hydrogenated MDI is used as component (e) in the curable composition, a synthetic leather with better weather resistance can be obtained from the curable composition, so it is suitably used as a curable composition for the surface layer.

[0072] <Component (g)> In the curable composition of this embodiment, a chain extender: component (g) can be used as needed. Component (g) can be used for adjusting physical properties such as the strength, abrasion resistance, and flexibility of the cured polyurethane. The chain extender is not particularly limited. For example, short-chain diols such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol; polyhydric alcohols such as trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, and glycerin; diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, and isophoronediamine; amino alcohols such as ethanolamine, diethanolamine, and triethanolamine, etc. can be mentioned. Among these, as component (g), from the viewpoint of reducing the local reaction with isocyanates, it is preferably a diol or polyhydric alcohol having 2 to 6 carbon atoms, and more preferably a diol having 2 to 6 carbon atoms. One type or two or more types of chain extenders may be used.

[0073] The addition amount of component (g) is preferably 30% by mass or less, more preferably 3% to 20% by mass, and still more preferably 5% to 10% by mass based on the total of components (a), (b), (c), and (d). It is desirable to adjust the amount of isocyanate in accordance with the addition amount of the chain extender. For example, with respect to the total of the hydroxyl equivalent weights of components (a), (b), (c), and (d) plus the equivalent weight (g) of the functional groups of component (g), the isocyanate equivalent of component (e) to be used is preferably adjusted to be 0.7 to 1.3 equivalents, more preferably 0.8 to 1.2 equivalents, and still more preferably 0.9 to 1.1 equivalents.

[0074] <Inert organic solvent> The curable composition of this embodiment may contain an inert organic solvent as needed to adjust the workability during urethane production. The content of the inert organic solvent is preferably 40% by mass or less, more preferably 3% by mass or more and 30% by mass or less, still more preferably 5% by mass or more and 20% by mass or less, based on the total amount of the curable composition. Adding an inert organic solvent is effective for reducing the viscosity of the curable composition, improving the workability during synthetic leather production, and further improving the appearance of the resulting synthetic leather. However, the solvent used in the process is released into the atmosphere through a drying process unless an expensive solvent recovery device is introduced, which may lead to an increase in VOC (Volatile Organic Compounds). From the perspective of reducing the environmental impact, it is preferable to keep the content of the inert organic solvent at a low level or, ideally, not use any solvent at all.

[0075] The inert organic solvent is not particularly limited as long as it is an organic solvent that is substantially inert to polyisocyanate, and it is preferably one that does not have active hydrogen. The inert organic solvent is not particularly limited, but examples include hydrocarbons such as pentane, hexane, heptane, octane, decane, petroleum ether, petroleum benzine, ligroin, petroleum spirit, cyclohexane, and methylcyclohexane; fluorinated inert liquids such as fluorinated oils like trichlorofluoroethane, tetrachlorodifluoroethane, and perfluoroether; perfluorocyclohexane, perfluorobutyltetrahydrofuran, perfluorodecalin, perfluoro-n-butylamine, perfluoropolyether, dimethylpolysiloxane, etc. These may be used alone or as a mixture. Further examples of the inert organic solvent include single or mixed solvents such as methyl ethyl ketone (also referred to as MEK), acetone, ethyl acetate, butyl acetate, toluene, xylene, dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide, diethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, tetrahydrofuran (THF), dioxane, etc.

[0076] <Other Additives> In the curable composition of this embodiment, a curing accelerator (catalyst), filler, flame retardant, dye, organic or inorganic pigment, mold release agent, fluidity modifier, plasticizer, antioxidant, ultraviolet absorber, light stabilizer, defoaming agent, leveling agent, colorant, foaming agent, etc. can be added according to various applications.

[0077] The curing accelerator is not particularly limited, and examples thereof include amines and metal catalysts. The effect promoter of amines is not particularly limited, and examples thereof include, for example, triethylamine which is a monoamine, N,N-dimethylcyclohexylamine, tetramethylethylenediamine which is a diamine, other triamines, cyclic amines, alcohol amines such as dimethylethanolamine, ether amines, etc. The metal catalyst is not particularly limited, and examples thereof include, for example, potassium acetate, potassium 2-ethylhexanoate, calcium acetate, lead octylate, dibutyltin dilaurate, tin octylate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octylate, zinc neodecanoate, phosphine, phospholine, etc.

[0078] The filler and pigment are not particularly limited, and examples thereof include, for example, woven fabric, glass fiber, carbon fiber, polyamide fiber, mica, kaolin, bentonite, metal powder, azo pigment, carbon black, clay, silica, talc, gypsum, alumina white, barium carbonate, etc.

[0079] The mold release agent, fluidity modifier, and leveling agent are not particularly limited, and examples thereof include, for example, silicone, aerosil, wax, stearate, polysiloxane such as BYK-331 (manufactured by BYK Chemical Co., Ltd.).

[0080] As the additives used in this embodiment, it is preferable to use at least an antioxidant, a light stabilizer, a heat stabilizer, and a flame retardant. The antioxidant is not particularly limited. For example, phosphorus compounds such as phosphoric acid, phosphorous acid, aliphatic, aromatic or alkyl group-substituted aromatic esters, hypophosphorous acid derivatives, phenylphosphonic acid, phenylphosphinic acid, diphenylphosphonic acid, polyphosphonate, dialkyl pentaerythritol diphosphite, dialkyl bisphenol A diphosphite; phenolic derivatives, especially hindered phenol compounds, sulfur-containing compounds such as thioether-based, dithiocarboxylate-based, mercaptobenzimidazole-based, thiocarbanyl amide-based, thiodipropionate esters; tin-based compounds such as tin maleate, dibutyltin monoxide can be used. These may be used alone or in combination of two or more. The flame retardant is not particularly limited. For example, brominated flame retardants such as tetrabromobisphenol A, decabromodiphenyl ether, octabromodiphenyl ether, hexabromocyclododecane, decabromodiphenylethane, bistribromophenoxyethane, polydibromophenylene oxide, tetrabromophthalic anhydride, TBA carbonate oligomer, and brominated polystyrene; halogenated flame retardants such as chlorinated polyphenyl, perchloropentacyclodecane, and hexachlorocyclopentadiene derivatives; phosphorus-based flame retardants such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, cresyl bis(2,6-xylenyl) phosphate, 2-ethylhexyl phosphate, dimethylmethyl phosphate, resorcinol bis(diphenyl) phosphate, bisphenol A bis(diphenyl) phosphate, bisphenol A bis(dicresyl) phosphate, diethyl-N,N-bis(2-hydroxyethyl)aminomethyl phosphate, phosphoric acid amide, organic phosphine oxide, and red phosphorus; nitrogen-based flame retardants such as ammonium polyphosphate, phosphazene, cyclophosphazene, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives, triazine, melamine cyanurate, succinoguanamine, ethylenedimelamine, triguanamine, triazinyl cyanurate salt, melem, melam, tris(β-cyanoethyl) isocyanurate, acetoguanamine, guanylmelamine sulfate, melem sulfate, melam sulfate; metal salt-based flame retardants such as potassium diphenylsulfone-3-sulfonate, aromatic sulfonimide metal salts, and alkali metal salts of polystyrene sulfonic acid; hydrated metal-based flame retardants such as aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, and tin oxide;Inorganic flame retardants such as silica, aluminum oxide, iron oxide, titanium oxide, manganese oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, tin oxide, antimony oxide, nickel oxide, copper oxide, tungsten oxide, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc stannate, etc.; silicone flame retardants such as silicone powder, etc. can be mentioned. Among them, from the viewpoint of environmental load, phosphorus-based flame retardants are preferably used.

[0081] <Method for producing a curable composition> The curable composition of this embodiment can be produced by a generally industrially used production method.

[0082] The curable composition of this embodiment can be produced, for example, by a method of collectively mixing and reacting component (a), component (b), component (c), component (d), component (e), and optionally component (g) (hereinafter referred to as the "one-shot method"). Also, as described above, the curable composition of this embodiment may be a mixture containing component (a), component (b), component (c), component (d), component (e), and optionally component (g) as a curable composition. One or more of component (a), component (b), component (c), component (d), and optionally component (g) are selected and reacted with component (e) to prepare an isocyanate group-terminated prepolymer composition. The isocyanate group-terminated prepolymer composition and a mixture containing one or more of component (a), component (b), component (c), component (d), and optionally component (g) may be used as the curable composition. At that time, two or more isocyanate group-terminated prepolymers may be prepared and blended respectively. That is, the curable composition of the present embodiment can be produced, for example, by first reacting component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) with component (e) in advance to prepare a prepolymer composition having isocyanate groups at the terminals, and then blending component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) (hereinafter referred to as the "prepolymer method". One or more prepolymers may be used).

[0083] Alternatively, a hydroxyl-terminated prepolymer composition obtained by selecting one or more from among component (a), component (b), component (c), component (d), and, if necessary, component (g) and reacting them with component (e) as described above may be prepared, and a mixture obtained by blending the hydroxyl-terminated prepolymer composition, one or more from among component (a), component (b), component (c), component (d), and, if necessary, component (g), and component (e) and / or one or more of the isocyanate-group-terminated prepolymers prepared as described above may be used as the curable composition. In that case, two or more hydroxyl-terminated prepolymers may be prepared and blended respectively. That is, the curable composition of the present embodiment can be produced, for example, by first reacting component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) with component (e) in advance to prepare a prepolymer composition having hydroxyl groups at the terminals, and then blending one or more from among component (a), component (b), component (c), component (d), and, if necessary, component (g), component (e) and / or the isocyanate-group-terminated prepolymer prepared as described above (hereinafter referred to as the "prepolymer method". One or more prepolymers may be used).

[0084] (One-shot method) When obtaining a curable composition by the one-shot method, the amount of component (e) used is usually 0.7 to 1.3 equivalents, more preferably 0.8 to 1.2 equivalents, and even more preferably 0.9 to 1.1 equivalents as the isocyanate equivalent based on the total hydroxyl group equivalents of components (a), (b), (c), (d), and (g). When the amount of component (e) used is 0.7 equivalent or more and 1.3 equivalents or less, the molecular weight of the resulting polyurethane can be appropriately controlled, and it tends to have excellent mechanical properties such as strength, elongation, and abrasion resistance. When obtaining a curable composition by the one-shot method, an inert organic solvent can be used for the purpose of improving the workability during synthetic leather production. Generally, when a polyol (corresponding to components (a), (b), (c), (d), and (g)) and a polyisocyanate (corresponding to component (e)) are mixed, the viscosity of the curable mixture increases with time. By adding an inert organic solvent to the curable composition, the viscosity of the composition can be lowered, and the coating time can tend to be lengthened.

[0085] When using other additives, the other additives may be added simultaneously when components (a), (b), (c), (d), (g), and (e) are mixed together, or may be premixed with components (a), (b), (c), (d), (g), and (e).

[0086] (Prepolymer method) In the prepolymer method, an isocyanate group-terminated prepolymer composition and / or a hydroxyl group-terminated prepolymer composition obtained by reacting one or more selected from components (a), (b), (c), (d), and optionally component (g) are prepared, and a mixture of the isocyanate group-terminated prepolymer composition and / or the hydroxyl group-terminated prepolymer composition and one or more selected from components (a), (b), (c), (d), component (e), and optionally component (g) may be used as the curable composition. At that time, two or more isocyanate group-terminated prepolymers and / or hydroxyl group-terminated prepolymer compositions may be prepared and blended respectively. Specifically, first, component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) are reacted in advance to prepare a prepolymer composition having an isocyanate group or a hydroxyl group at the terminal (simply referred to as a prepolymer composition), and then component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) and / or component (e) are added.

[0087] When synthesizing the isocyanate group-terminated prepolymer composition, the ratio of component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g) to component (e) is such that the equivalent ratio of the isocyanate group contained in component (e) to the hydroxyl group contained in component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g), [isocyanate equivalent] / [hydroxyl equivalent], is adjusted to be 1.5 to 3.0, preferably 1.8 to 2.7, more preferably 1.9 to 2.3. When [isocyanate equivalent] / [hydroxyl equivalent] during the synthesis of the isocyanate group-terminated prepolymer is 1.5 or more, the molecular weight of the resulting prepolymer is appropriately controlled, the viscosity of the prepolymer is suppressed, and the use of an organic solvent can be reduced. When [isocyanate equivalent] / [hydroxyl equivalent] during the synthesis of the isocyanate group-terminated prepolymer is 3.0 or less, unreacted component (e) is suppressed, and the resulting polyurethane tends to be prevented from becoming hard. When synthesizing the hydroxyl-terminated prepolymer composition, the ratio of component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g) to component (e) is such that the equivalent ratio of the isocyanate groups contained in component (e) to the hydroxyl groups contained in component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g), [hydroxyl equivalent] / [isocyanate equivalent], is adjusted to be 1.5 to 3.0, preferably 1.8 to 2.7, more preferably 1.9 to 2.3. When [hydroxyl equivalent] / [isocyanate equivalent] during the synthesis of the hydroxyl-terminated prepolymer is 1.5 or more, the molecular weight of the resulting prepolymer is appropriately controlled, the viscosity of the prepolymer is suppressed, and the use of organic solvents can be reduced. When [hydroxyl equivalent] / [isocyanate equivalent] during the synthesis of the hydroxyl-terminated prepolymer is 3.0 or less, the molecular weight and molecular weight distribution of the polymer can be appropriately controlled, and the physical properties of the resulting polyurethane tend to be good.

[0088] The ratio of the isocyanate-group-terminated prepolymer composition obtained by previously reacting component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) to component (e) is preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1, expressed as [isocyanate equivalent of the prepolymer composition] / [hydroxyl value equivalent of component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g)]. When [isocyanate equivalent of the prepolymer composition] / [hydroxyl value equivalent of component (a) and / or component (b) and / or component (c) and / or component (d) and / or component (g)] is 0.7 equivalent or more and 1.3 equivalents or less, the molecular weight of the resulting polyurethane can be appropriately controlled, and it tends to be excellent in mechanical physical properties such as strength, elongation, and abrasion resistance. In addition, the ratio of the hydroxyl-terminated prepolymer composition to component (e) and / or the isocyanate-terminated prepolymer is preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1, expressed as [hydroxyl value equivalent of the prepolymer composition] / [isocyanate equivalent of component (e) and / or the isocyanate-terminated prepolymer]. When [hydroxyl value equivalent of the prepolymer composition] / [isocyanate equivalent of component (e) and / or the isocyanate-terminated prepolymer] is 0.7 equivalent or more and 1.3 equivalents or less, the molecular weight of the resulting polyurethane can be appropriately controlled, and it tends to have excellent mechanical properties such as strength, elongation, and abrasion resistance.

[0089] When obtaining a curable composition by the prepolymer method, an inert organic solvent can be used for the purpose of improving workability during the production of synthetic leather. The amount of the inert organic solvent used is preferably 40% by mass or less. When the isocyanate-terminated prepolymer composition and the polycarbonate polyol are mixed, the viscosity of the curable composition increases with time. By adding an inert organic solvent to the curable composition, the viscosity of the composition can be lowered, and the coating time can tend to be extended.

[0090] When using an inert organic solvent, since the viscosity becomes high during prepolymer synthesis, it is preferable to add an inert organic solvent to component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) in advance before performing the prepolymer reaction. Also, when using an inert organic solvent during prepolymer synthesis, the reaction can tend to proceed uniformly.

[0091] When using other additives, since the viscosity becomes high during prepolymer synthesis, it is preferable to add an inert organic solvent to component (a) and / or component (b) and / or component (c) and / or component (d) and, if necessary, component (g) in advance before performing the prepolymer reaction.

[0092] When comparing the one-shot method and the prepolymer method, the prepolymer method makes it easier to adjust the structure of the soft segment portion. As a result, phase separation between the soft segment and the hard segment is more likely to occur, and the resulting polyurethane tends to be excellent in flexibility and low-temperature properties. Therefore, the prepolymer method is preferred.

[0093] <Method for manufacturing synthetic leather> A synthetic leather can be manufactured from the curable composition of the present embodiment. Examples of the method for manufacturing a synthetic leather from the curable composition of the present embodiment include a wet method in which the curable composition of the present embodiment is applied to or impregnated into a base material (base fabric) and wet-cured, and a dry method in which the curable composition of the present embodiment is applied to a release paper or a base material (base fabric) and dried. Furthermore, as a method for manufacturing a synthetic leather, after applying the curable composition of the present embodiment to a release paper to form a skin material, the curable composition of the present embodiment can be used as an adhesive layer thereon, and after laminating with a base material (base fabric), a transfer coating method (a type of dry method) in which the release paper is removed can also be used. That is, the composition of the present embodiment can be used for an adhesive layer for synthetic leather. Since the curable composition of the present embodiment can suppress the amount of the inert organic solvent used, the dry method (transfer coating method) is preferably used.

[0094] The method for manufacturing a synthetic leather will be described below by taking the dry method as an example. As the base material (base fabric), various materials can be used. For example, fibrous base materials can be mentioned. As the fibrous base material, there are fibrous aggregates formed by shaping fibers into non-woven fabrics, woven fabrics, knitted fabrics, raised fabrics subjected to buffing treatment, etc., or those in which each fiber of the fibrous aggregate is bonded by an elastic polymer, etc. Examples of the fibers used in this fibrous aggregate include natural fibers such as cotton, hemp, and wool, regenerated or semi-synthetic fibers such as rayon and acetate, and synthetic fibers such as polyamide, polyester, polyacrylonitrile, polyvinyl alcohol, and polyolefin. These fibers may be single-spun fibers or mixed-spun fibers. Other base materials include paper, release paper, plastic films of polyester and polyolefin, metal plates such as aluminum, and glass plates.

[0095] The curable composition of this embodiment can be applied by generally used methods. Examples of the coating method include a floating knife coater, a knife over roll coater, a reverse roll coater, a roll doctor coater, a gravure roll coater, a kiss roll coater, etc.

[0096] The obtained synthetic leather can be used as it is. Alternatively, this synthetic leather can be obtained in a mode where a polymer solution or emulsion such as a polyurethane resin, a vinyl chloride or cellulose-based resin is applied to the synthetic leather for the purpose of imparting various properties. Also, the synthetic leather can be obtained in a mode of a laminate obtained by laminating and then peeling off the release paper after laminating a coating film obtained by drying the above polymer solution or emulsion separately coated on the release paper.

[0097] Hereinafter, this embodiment will be described with reference to the drawings. The drawings and manufacturing conditions described below are one form of this embodiment, and this embodiment is not limited thereto.

[0098] FIG. 1 is a schematic cross-sectional view of a synthetic leather laminate manufactured by the dry method shown in FIG. 2. The structure of this laminate has an epidermal layer 2 via an adhesive layer 3 on a base material (a knitted fabric made of polyester fibers) 4. A release paper 1 used during production is attached to the outermost layer, but it is peeled off for use.

[0099] FIG. 2 is a schematic diagram showing one method for manufacturing a dry synthetic leather laminate sheet using the curable composition of the present embodiment. In this manufacturing method, first, a resin for the epidermal layer (synthesis example) adjusted to a predetermined temperature is allowed to flow down onto the release paper 1 (usually with a leather-like pattern applied) via a coater 5.

[0100] The coater and the resin for the epidermal layer are usually adjusted to a temperature of 20 to 80°C, preferably 30 to 70°C, more preferably 40 to 60°C. When the temperature of the coater and the resin for the epidermal layer is 20°C or higher, the resin viscosity is suppressed, the flow rate is stable, and coating unevenness is less likely to occur. Also, when the temperature of the coater and the resin for the epidermal layer is 80°C or lower, the volatilization of the solvent used as a diluent is less likely to occur, and it is easier to obtain a uniform thickness of the epidermal layer.

[0101] Thereafter, after forming a sheet of a certain thickness through a coating roll 8, it is passed through a dryer 11 to cure and dry the inert organic solvent to form the epidermal layer 2 of the synthetic leather. The temperature of the dryer is usually set to 60 to 150°C, preferably 70 to 130°C, more preferably 80 to 110°C. The drying time is usually 2 to 15 minutes, preferably 3 to 10 minutes, more preferably 4 to 7 minutes.

[0102] The resin for the epidermal layer is not particularly limited, but in addition to being adjusted by the method shown in the synthesis example, commercially available products may also be used. Although not particularly limited, for example, those made by DIC; "Chrysbon" series, and those made by Dainichi Seika Kogyo; "Resamin" series, etc. can be mentioned.

[0103] Next, each raw material of the curable composition of the present embodiment adjusted to a predetermined temperature is mixed by a mixing head 6, and the curable composition of the present embodiment thus obtained is allowed to flow down to form the adhesive layer 3. When applying the one-shot method to the production of the adhesive layer, the main agent (component (a), component (b), component (c), component (d), and optionally component (g)), the curing agent (component (e)), and optionally an inert organic solvent and additives are fed separately or simultaneously and continuously into the mixing head 6, mixed, and flow down onto the skin layer. When applying the prepolymer method to the production of the adhesive layer, a prepolymer composition (one type or two or more types), and other raw materials (component (a), component (b), component (c), component (d), and optionally component (g)), and optionally an inert organic solvent and additives are fed separately or simultaneously and continuously into the mixing head 6, mixed, and flow down onto the skin layer. By using the curable composition for the adhesive layer, a composite leather with good low-temperature characteristics, excellent physical property balance of flexibility (tactility), chemical resistance, and heat resistance can be obtained, and a synthetic leather with less or no use of the solvent used can be obtained.

[0104] Each component before mixing is usually adjusted to a temperature of 20 to 60°C, preferably 30 to 50°C, more preferably 35 to 45°C. Also, the temperature of the mixing head 6 is usually adjusted to a temperature of 20 to 60°C, preferably 30 to 50°C, more preferably 35 to 45°C. Since the temperature of each component before mixing and the temperature of the mixing head 6 are 20°C or higher, the viscosity of the raw materials used, particularly the polycarbonate polyol, is suppressed, and the flow rate tends to be stable. Further, since the temperature of each component before mixing and the temperature of the mixing head 6 are 60°C or lower, the curing rate of the curable composition of the present embodiment is appropriately controlled, a rapid increase in the viscosity of the curable composition is suppressed, and a uniform thickness of the synthetic leather tends to be obtained.

[0105] Thereafter, after forming a sheet shape with a certain thickness through the coating roll 8, it is passed through the dryer 11 to cure and dry the inert organic solvent to form the adhesive layer 3 of the synthetic leather. Next, the base material 4 and the adhesive layer 3 are overlapped and crimped with the crimping roll 9 to obtain the sheet structure 7, which is then wound by the winding roll 10 to obtain the desired synthetic leather laminate. The temperature of the dryer 11 is usually set at 50 to 140 °C, preferably 60 to 130 °C, more preferably 80 to 120 °C. The drying time is usually 2 to 15 minutes, preferably 3 to 12 minutes, more preferably 4 to 10 minutes.

[0106] In Fig. 2, a manufacturing example of synthetic leather including three layers of the surface layer / adhesive layer / base material is shown. However, by increasing the thickness of the adhesive layer to give it the function of an intermediate layer, a pseudo-four-layer structure of the surface layer / adhesive layer and intermediate layer / base material can also be obtained. Of course, it is also possible to use an intermediate layer separately to form a structure such as the surface layer / adhesive layer / intermediate layer / adhesive layer / base material. The adhesiveness between the surface layer and the base material is controlled by adjusting the curing state of the curable composition. Specifically, it can be obtained by crimping with the base material in a state where the curable composition of the present embodiment is not completely cured. A cured product can be obtained by controlling the temperature and time. As an example, the curing temperature of the dryer 11 is set at 50 to 140 °C, preferably 60 to 130 °C, more preferably 80 to 120 °C. The drying time is usually set at 2 to 15 minutes, preferably 3 to 12 minutes, more preferably 4 to 10 minutes.

[0107] <Use> The synthetic leather obtained by using the curable composition of the present embodiment can be used for automotive interior materials such as automotive seats, furniture such as sofas, clothing, shoes, bags, and other miscellaneous products.

Examples

[0108] Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded. In the following examples and comparative examples, the analysis and evaluation methods of the physical properties of each component are as follows.

[0109] [Analysis and Evaluation of Polycarbonate Polyol] <Hydroxyl Value of Polycarbonate Polyol> It was measured according to JIS K1557-1.

[0110] <Composition (Copolymerization Ratio) of Polycarbonate Polyol> 1 g of a sample of polycarbonate polyol was taken into a 100 mL eggplant flask, 30 g of ethanol and 4 g of potassium hydroxide were added, and the mixture was reacted at 100 °C for 1 hour. After the reaction solution was cooled to room temperature, 2 - 3 drops of phenolphthalein were added as an indicator and neutralized with hydrochloric acid. After cooling in a refrigerator for 1 hour, the precipitated salt was removed by filtration and analyzed using gas chromatography (GC). The GC analysis was performed using a gas chromatograph GC-14B (manufactured by Shimadzu Corporation, Japan) equipped with DB-WAX (manufactured by J&W, USA) as a column, using diethylene glycol diethyl ether as an internal standard, and a flame ionization detector (FID) as a detector to perform quantitative analysis of each component. The temperature rising profile of the column was maintained at 60 °C for 5 minutes and then raised to 250 °C at 10 °C / min. From the molar ratio of each alcohol component detected from the above analysis results, the composition (copolymerization ratio) of the polycarbonate polyol was determined.

[0111] <Average Functionality of Polycarbonate Polyol> The average functionality of the polycarbonate polyol synthesized using only diol monomer as a raw material was set to 2. When a polyfunctional monomer was included as a raw material, the average functionality was determined as follows. The number average molecular weight (Mn) of the polycarbonate polyol was determined by gel permeation chromatography (GPC) analysis in which a calibration curve was prepared using a standard polystyrene having a known molecular weight (the GPC apparatus and analysis conditions are referred to below). The average functionality per molecule (n) was determined by formula (5) using the separately analyzed hydroxyl value and the number average molecular weight (Mn) determined by GPC.

[0112] Average functionality (n)=[Mn]×([OH value]×10 -3 / 56.1) (5)

[0113] (GPC Device and Analysis Conditions) GPC Device: HLC-8320 manufactured by Tosoh Corporation Column: 1 piece of TSKgel G4000H 1 piece of G3000H 2 pieces of G2000H Eluent: Tetrahydrofuran (THF) Flow Rate: 1.0 mL / min Column Temperature: 40 °C RI Detector: RI (built-in in device HLC-8320)

[0114] <Measurement of Melt Viscosity> After preheating the polycarbonate polyol to 50 °C, the melt viscosity was measured at 50 °C using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., TVE-22HT, cone: No. 6).

[0115] [Analysis and Evaluation of Prepolymer Composition] <Measurement of Melt Viscosity> After preheating the prepolymer composition to 50 °C, the melt viscosity was measured at 50 °C using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., TVE-22HT, cone: No. 6) under a nitrogen atmosphere.

[0116] <Measurement of Isocyanate Group Concentration> 10 mL of a mixed solution of di-n-butylamine / toluene (mass ratio: 25.85 / 865) was diluted with 10 mL of dimethylformamide (DMF), and then titrated with a 0.1 N hydrochloric acid propanol solution. The amount of hydrochloric acid propanol required for neutralization was measured and used as the blank value. Then, 2 g of the prepolymer solution was taken out, 10 mL of the mixed solution of di-n-butylamine / toluene was added, and after stirring at room temperature for 30 minutes, it was diluted with 10 mL of DMF in the same manner as the blank measurement, titrated with a 0.1 N hydrochloric acid propanol solution, and the amount of hydrochloric acid propanol solution required for neutralization was measured to quantify the amount of remaining amine. The concentration of the isocyanate group was determined from the volume of the hydrochloric acid propanol solution required for neutralization using the following formula (6).

[0117] Isocyanate group concentration (mass%) = (V1 - V2)×f×42×100 / (W×1000) (6)

[0118] V1: Amount of 0.1 N hydrochloric acid propanol solution required for blank measurement (mL) V2: Amount of 0.1 N hydrochloric acid propanol solution required for this measurement (mL) W: Sample used for this measurement (g) f: Factor of hydrochloric acid propanol solution

[0119] [Analysis and Evaluation of Polyurethane Film] <Preparation of Polyurethane Film> Each component of the curable composition of the present invention pre - heated to 40°C was added to a separable four - necked flask equipped with a stirring blade (4 - paddle type inclined at 45 degrees) with a volume of 200 mL to obtain 80 g of a cured composition under a nitrogen atmosphere, stirred at 40°C for 5 minutes, then using an applicator, it was applied onto a polypropylene resin sheet (width 100 mm, length 1200 mm, thickness 1 mm) with a width of 80 mm, a length of 100 mm, and a thickness of 0.6 mm, dried on a hot plate with a surface temperature of 60°C for 2 hours, and then in an oven at 100°C for 12 hours. Further, it was left standing for 12 hours or more under constant temperature and humidity of 23°C and 55% RH to obtain a polyurethane film. The obtained polyurethane film was subjected to evaluation of various physical properties.

[0120] <Flexibility of Polyurethane Film> The flexibility of the polyurethane film was evaluated by 5 inspectors, and the feel when touching the film by hand was evaluated. The evaluation criteria were as follows. ○ indicates that it was flexible, and the evaluation results of the 5 inspectors were consistent. △ indicates that it was slightly hard, and the evaluation results of the 5 inspectors were consistent. × indicates that it was hard, and the evaluation results of the 5 inspectors were consistent.

[0121] <Appearance of Polyurethane Film> The surface appearance of the polyurethane film prepared above was visually judged according to the following criteria. ○ indicates that the surface was smooth. △ indicates that slight streaks were observed in the applicator moving direction on the surface. × indicates that many streaks were observed in the applicator moving direction on the surface.

[0122] <Measurement of molecular weight> A part of the above polyurethane film was cut out, and an N,N-dimethylacetamide solution was prepared so that the concentration of polyurethane became 0.1 mass%. Using a GPC device [manufactured by Tosoh Corporation, product name "HLC-8320" (column: Tskgel SuperHM-H·4 pieces), and a solution prepared by dissolving 2.6 g of lithium bromide in 1 L of dimethylacetamide was used as the eluent], the number average molecular weight (Mn) and weight average molecular weight (Mw) in terms of standard polystyrene were measured.

[0123] <Evaluation of oleic acid resistance> A 3 cm × 3 cm test piece was cut out from the polyurethane film. After measuring the mass of the test piece with an analytical balance, it was put into a 250 mL glass bottle containing 50 mL of oleic acid as the test solvent and left standing in a constant temperature bath under a nitrogen atmosphere at 80 °C for 16 hours. After the test, the test piece was taken out, gently wiped with a paper wiper on both sides, and then the mass was measured with an analytical balance, and the mass change rate (increase rate) from before the test was calculated. The closer the mass change rate is to 0%, the better the oleic acid resistance.

[0124] <Evaluation of ethanol resistance> After preparing a urethane film in the same manner as in the above <Evaluation of oleic acid resistance>, a 3 cm × 3 cm test piece of the urethane film was cut out. After measuring the mass of the test piece with an analytical balance, it was put into a glass petri dish with an inner diameter of 10 cmφ containing 50 mL of ethanol as the test solvent and immersed at room temperature of about 23 °C for 1 hour. After the test, the test piece was taken out, gently wiped with a paper wiper, and then the mass was measured with an analytical balance, and the mass change rate (increase rate) from before the test was calculated. The closer the mass change rate is to 0%, the better the ethanol resistance.

[0125] <Measurement of Glass Transition Temperature (Tg)> A test piece with a width of 10 mm, a length of 40 mm, and a thickness of 0.4 mm was cut out from the polyurethane film. Using a viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, [TA7000 series, DMA7100]), the test piece was set with a distance of 20 mm between the chucks, and the viscoelasticity was measured while heating from -100 °C to 100 °C at a rate of 5 °C / min. The peak of tanδ was read to obtain the glass transition temperature (Tg).

[0126] <Tensile Test at Room Temperature (23 °C)> In accordance with JIS K6301(2010), a polyurethane test piece in the form of a strip with a width of 10 mm, a length of 100 mm, and a thickness of approximately 0.5 mm was subjected to a tensile test at a temperature of 23 °C (relative humidity 55%) using a tensile testing machine (manufactured by Orientec Co., Ltd., product name "Tensilon, model RTE-1210") with a distance of 20 mm between the chucks and a tensile speed of 100 mm / min. The stress at the time when the test piece was stretched by 100%, as well as the breaking point strength and the breaking point elongation, were measured.

[0127] <Low Temperature Tensile Test> In accordance with JIS K6301(2010), a polyurethane test piece in the form of a strip with a width of 10 mm, a length of 100 mm, and a thickness of approximately 0.5 mm was placed with a film at a distance of 20 mm between the chucks on a tensile testing machine (manufactured by Orientec Co., Ltd., product name "Tensilon, model RTE-1210") equipped with a thermostatic bath (manufactured by Orientec Co., Ltd., "model TLF-R3T-E-W"). Subsequently, after standing still at -20 °C for 5 minutes, a tensile test was carried out at a tensile speed of 100 mm / min, and the stress at the time when the test piece was stretched by 100% was measured.

[0128] <Evaluation of Heat Resistance> The polyurethane film was formed into a strip with a width of 10 mm, a length of 100 mm, and a thickness of approximately 50 μm, and was heated at 120 °C for 1000 hours in a gear oven. The breaking strength of the heated sample was measured in the same manner as in the above <Tensile Test at Room Temperature>, and the retention rate (%) was obtained.

[0129] <Evaluation of Hydrolysis Resistance> The polyurethane film was made into a strip shape with a width of 10 mm, a length of 100 mm, and a thickness of about 50 μm, and was heated in a thermostatic and humidistatic chamber at a temperature of 70 °C and a relative humidity of 95% for 400 hours. After heating, the sample was measured for the breaking strength in the same manner as the above <room temperature tensile test>, and the retention rate (%) was determined.

[0130] <Amount of solvent used> From the viewpoint of reducing the environmental load, it is preferable that the amount of solvent used in producing the urethane film is small. It was determined according to the following evaluation criteria. ◎ indicates that the amount of solvent used in the curable composition was in the range of 0 to less than 20%. 〇 indicates that the amount of solvent used in the curable composition was in the range of 20% or more and less than 40%. △ indicates that the amount of solvent used in the curable composition was in the range of 40% or more and less than 60%. × indicates that the amount of solvent used in the curable composition was 60% or more.

[0131] [Analysis and evaluation of synthetic leather] <Flexibility of synthetic leather> The flexibility of the synthetic leather was evaluated by 5 inspectors, and the feel when touching the synthetic leather by hand was evaluated. The evaluation criteria were as follows. ○ indicates that it was flexible, and the evaluation results of the 5 inspectors were consistent. △ indicates that it was slightly hard, and the evaluation results of the 5 inspectors were consistent. × indicates that it was hard, and the evaluation results of the 5 inspectors were consistent.

[0132] <Wear resistance of synthetic leather> A load of 9.8 N was applied to the friction element covered with a cotton cloth to wear the surface of the synthetic leather. The friction element reciprocated 10,000 times at a speed of 60 reciprocations per minute between 140 mm on the surface of the synthetic leather. The synthetic leather after wear was observed and judged according to the following criteria. ○ indicates that there were no cracks or breaks in the resin layer. △ indicates that cracks occurred in the resin layer. × indicates that breaks occurred in the resin layer.

[0133] <Low-temperature storage stability of synthetic leather> The synthetic leather was wound around a paper tube with a diameter of 10 cm and stored in a thermostat at a temperature of -20°C for 1 month. After removing the synthetic leather from the paper tube and leaving it in a constant temperature room at 23°C and 50% humidity for 1 day, the surface was visually observed and judged according to the following criteria. ○ indicates the case where there are no cracks or wrinkles at all. △ indicates the case where minute cracks or wrinkles of 1 mm or less are observed. × indicates the case where cracks or wrinkles exceeding 1 mm are observed.

[0134] <Low-temperature flexibility of synthetic leather> The synthetic leather was made into a strip shape with a width of 20 mm and a length of 50 mm, and a low-temperature bending test was carried out 30,000 times at a temperature of -10°C, a chuck distance of 30 mm, a stroke of 15 mm, and a speed of 100 times / minute using a Demachi bending tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). After taking out the test piece, the surface was visually observed and evaluated according to the following criteria. ○ indicates the case where there are no cracks or wrinkles at all. △ indicates the case where minute cracks or wrinkles of 1 mm or less are observed. × indicates the case where cracks or wrinkles exceeding 1 mm are observed or peeling between the base fabric and the adhesive layer is observed.

[0135] <Evaluation method of adhesiveness (peel strength)> In advance, a cut was made at the interface between the polyester base fabric and the polyurethane resin layer of the synthetic leather, and the peeled urethane resin layer and the base fabric were each fixed with a chuck. At a temperature of 23°C and a speed of 200 mm / min, in accordance with JIS K6854-2, a tensile tester (manufactured by Orientec Co., Ltd., using Tensilon model RTE-1210) was used to measure the peel strength between the polyurethane layer and the base fabric, and it was used as an evaluation of adhesiveness.

[0136] <Chemical resistance of synthetic leather> The synthetic leather was made into a strip shape with a width of 20 mm and a length of 50 mm, and 0.2 mL of oleic acid was dropped onto the surface layer and left standing for 30 minutes. After the test, the surface was wiped with a paper wiper, and then the appearance was confirmed and judged according to the following criteria. 〇 represents the case where there is no change in the texture of the grain or the synthetic leather. △ represents the case where the grain becomes thinner, swelling is observed in the synthetic leather, or a change in the texture of the synthetic leather is observed. × represents the case where the grain disappears or the adhesive layer peels off.

[0137] <Moisture and heat resistance of synthetic leather> The synthetic leather was made into a strip shape with a width of 10 mm and a length of 50 mm, and heated in a thermostatic and humidistatic chamber at a temperature of 90 °C and a relative humidity of 95% for 400 hours. After heating, the samples were taken out, the surface was visually observed and the touch was confirmed, and the judgment was made according to the following criteria. 〇 represents the case where there is no change in the texture of the grain or the synthetic leather. △ represents the case where the grain becomes thinner or a change in the texture of the synthetic leather is observed. × represents the case where the grain disappears or the adhesive layer peels off.

[0138] [Polymerization example 1 of polycarbonate polyol] 423 g (4.8 mol) of ethylene carbonate, 250 g (2.4 mol) of 1,5-pentanediol, and 284 g (2.4 mol) of 1,6-hexanediol were charged into a 2 L glass flask equipped with a rectification column filled with a regular packing and a stirring device. 0.09 g of titanium tetrabutoxide was added as a catalyst, and the reaction was carried out for 12 hours while dropping the reaction temperature from 140 to 160 °C, dropping the pressure from 10 kPa to 2 kPa, and distilling off the mixture of ethylene glycol and ethylene carbonate produced. Thereafter, the distillation was switched to simple distillation, and the reaction was carried out at 180 °C for 5 hours while gradually reducing the pressure to 0.5 kPa to distill out the monomer. The results of analyzing the obtained polycarbonate diol (also referred to as PC1) are shown in Table 1.

[0139] [Polymerization example 2 of polycarbonate polyol] Using the same apparatus as in Polymerization Example 1, polymerization was carried out in the same manner as in Polymerization Example 1, except that 423 g (4.8 mol) of ethylene carbonate, 216 g (2.4 mol) of 1,4-butanediol, 284 g (2.4 mol) of 1,6-hexanediol, and 0.09 g of titanium tetrabutoxide as a catalyst were used. The results of analyzing the obtained polycarbonate polyol (also referred to as PC2) are shown in Table 1.

[0140] [Polymerization Example 3 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that the polymerization time after switching to simple distillation was set to 1 hour. The results of analyzing the obtained polycarbonate polyol (also referred to as PC3) are shown in Table 1.

[0141] [Polymerization Example 4 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that the polymerization time after switching to simple distillation was set to 1.5 hours. The results of analyzing the obtained polycarbonate polyol (also referred to as PC4) are shown in Table 1.

[0142] [Polymerization Example 5 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that 423 g (4.8 mol) of ethylene carbonate, 229 g (2.2 mol) of 1,5-pentanediol, 236 g (2.0 mol) of 1,6-hexanediol, 122 g (0.7 mol) of 1,10-decanediol, and 0.09 g of titanium tetrabutoxide as a catalyst were charged into a 2 L glass flask equipped with a rectification column filled with a regular packing and a stirring device. The results of analyzing the obtained polycarbonate polyol (also referred to as PC5) are shown in Table 1.

[0143] [Polymerization Example 6 of Polycarbonate Polyol] Using the same apparatus as in Polymerization Example 1, polymerization was carried out in the same manner as in Polymerization Example 1, except that 423 g (4.8 mol) of ethylene carbonate, 507 g (4.3 mol) of 3-methyl-1,5-pentanediol, 59 g (0.5 mol) of 1,6-hexanediol, and 0.09 g of titanium tetrabutoxide as a catalyst were used. The results of analyzing the obtained polycarbonate polyol (also referred to as PC6) are shown in Table 1.

[0144] [Polymerization Example 7 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that 423 g (4.8 mol) of ethylene carbonate, 567 g (4.8 mol) of 1,6-hexanediol, and 0.09 g of titanium tetrabutoxide as a catalyst were charged into a 2 L glass flask equipped with a rectification column filled with a regular packing and a stirring device. The results of analyzing the obtained polycarbonate polyol (also referred to as PC7) are shown in Table 1.

[0145] [Polymerization Example 8 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that the polymerization time after switching to simple distillation was set to 3 hours. The results of analyzing the obtained polycarbonate polyol (also referred to as PC8) are shown in Table 1.

[0146] [Polymerization Example 9 of Polycarbonate Polyol] Polymerization was carried out in the same manner as in Polymerization Example 1, except that the polymerization time after switching to simple distillation was set to 10 hours. The results of analyzing the obtained polycarbonate polyol (also referred to as PC9) are shown in Table 1.

[0147]

Table 1

[0148] [Synthesis Example 1 of Prepolymer Composition] 30 g (0.12 mol) of MDI was charged into a 500 mL separable flask sealed with nitrogen gas and heated to 50°C. 120 g of methyl ethyl ketone (MEK) heated to 50°C and 120 g (0.06 mol) of polycarbonate polyol PC1 to which 0.007 g of dibutyltin dilaurate was added as a catalyst were added dropwise over 30 minutes with stirring. The reaction was carried out at 50°C with stirring for 2 hours to obtain a prepolymer composition having isocyanates at both ends. The results of analyzing the obtained prepolymer composition (also referred to as PCP1) are shown in Table 2.

[0149] [Synthesis Examples 2 to 14 of Prepolymer Compositions] A prepolymer composition was synthesized in the same manner as in Synthesis Example 1 of the prepolymer composition, except that the amounts of the polycarbonate polyol, MDI, and MEK used were the amounts shown in Table 2. The results of analyzing the obtained prepolymer compositions (each also referred to as PCP2 to PCP14) are shown in Table 2.

[0150] [Table 2]

[0151] [Example 1] 10 g of polycarbonate polyol PC1 pre-heated to 60°C, 10 g of polycarbonate polyol PC3, 7 g of polyester polyol PEs1, 7 g of polyether polyol PE1, 10 g of MDI pre-dissolved at 80°C, 8.1 g of methyl ethyl ketone (MEK), and 0.003 g of dibutyltin dilaurate as a catalyst were charged into a 200 mL separable flask with a stirring blade under nitrogen seal. After stirring at 60°C for 3 minutes, it was applied onto a polypropylene resin sheet (width 100 mm, length 1200 mm, thickness 1 mm) using an applicator, with a width of 80 mm, length of 100 mm, and thickness of 0.6 mm, and dried on a hot plate at a surface temperature of 60°C for 2 hours, and then in an oven at 100°C for 12 hours. Further, it was left standing for 12 hours or more under constant temperature and humidity of 23°C and 55% RH to obtain a polyurethane film. The obtained polyurethane film was subjected to evaluation of various physical properties. The evaluation results are shown in Table 3.

[0152] [Examples 2 to 15] A polyurethane film was obtained in the same manner as in Example 1, except that the types and amounts of the raw materials were the same as those described in Table 3. The evaluation results of the obtained polyurethane film are shown in Table 3.

[0153] [Comparative Examples 1 to 5] A polyurethane film was obtained in the same manner as in Example 1, except that the types and amounts of the raw materials were the same as those described in Table 3. The evaluation results of the obtained polyurethane film are shown in Table 3.

[0154]

Table 3

[0155] [Polymerization Example of Polyester Polyol] Into a 2 L glass flask equipped with a nitrogen-substituted stirring device, 584 g (4.0 mol) of adipic acid and 567 g (4.8 mol) of 3-methyl-1,5-pentanediol were charged. 0.02 g of titanium tetrabutoxide was added as a catalyst, and the reaction was carried out at a reaction temperature of 190 to 220 °C under normal pressure while distilling off the generated water. While sampling appropriately, the reaction was stopped when the target hydroxyl value was reached, and PEs2 was obtained. PEs3: Kuraray Polyol P-1010 (polyester polyol, hydroxyl value 112 mg KOH / g, functionality 2.0, manufactured by Kuraray) PEs4: Kuraray Polyol P-3010 (polyester polyol, hydroxyl value 37.3 mg KOH / g, functionality 2.0, manufactured by Kuraray) PE1: PTMG2000 (polyether polyol, hydroxyl value 56.4 mg KOH / g, functionality 2.0, manufactured by Mitsubishi Chemical) PE2: PTMG-1800 (polyether polyol, hydroxyl value 63.2 mg KOH / g, functionality 2.0, manufactured by Asahi Kasei) PE3: PTMG1000 (polyether polyol, hydroxyl value 112 mg KOH / g, functionality 2.0, manufactured by Mitsubishi Chemical) PE4: PTMG3000 (polyether polyol, hydroxyl value 38.0 mg KOH / g, functionality 2.0, manufactured by Mitsubishi Chemical) CE1: 1,4-butanediol (manufactured by Mitsubishi Chemical, chain extender)

[0156] [Urethane solution for epidermal layer: Surface layer synthesis example 1] 60 g of polycarbonate polyol PC1 preheated to 60°C, 6 g of polyester polyol PEs1, 12 g of hydrogenated MDI, 300 g of methyl ethyl ketone (MEK), and 0.003 g of dibutyltin dilaurate as a catalyst were charged into a 500 mL separable flask equipped with a stirring blade under nitrogen seal. After stirring at 60°C for 30 minutes, 1 g of chain extender CE1 was added, and then the temperature was raised to 80°C and stirring was continued. The reaction was continued until an increase in viscosity was observed, 1 g of ethanol was added to stop the reaction, and a urethane solution for the skin layer was obtained.

[0157] [Example 16] 100 g of prepolymer composition PCP1 preheated to 50°C, 5 g of polycarbonate polyol PC3, 15 g of polyester polyol PEs1, and 15 g of polyether polyol PE1 were charged into a 200 mL separable flask equipped with a stirring blade under nitrogen seal. After stirring at 50°C for 5 minutes, using an applicator, it was applied onto a polypropylene resin sheet (width 100 mm, length 1200 mm, thickness 1 mm) with a width of 80 mm, a length of 100 mm, and a thickness of 0.6 mm, and dried on a hot plate at a surface temperature of 60°C for 2 hours and then in an oven at 100°C for 12 hours. Further, it was allowed to stand for 12 hours or more under constant temperature and humidity of 23°C and 55% RH to obtain a polyurethane film. The obtained polyurethane film was subjected to evaluation of various physical properties. The evaluation results are shown in Table 4.

[0158] [Examples 17 - 20] A polyurethane film was obtained in the same manner as in Example 16 except that the types and amounts of the prepolymer composition and polycarbonate polyol were the types and amounts described in Table 4. In addition, components (a), (b), (c), (d), and, if necessary, component (g) are included in the prepolymer component and / or polyol. The evaluation results of the obtained polyurethane film are shown in Table 4.

[0159] [Comparative Example 6] A polyurethane film was obtained in the same manner as in Example 16, except that the types and amounts of the prepolymer composition and the polycarbonate polyol were the types and amounts described in Table 4. The evaluation results of the obtained polyurethane film are shown in Table 4.

[0160] [Table 4]

[0161] [Example 21] Using the same apparatus as shown in Figure 2, a release paper having a embossed pattern (manufactured by Lintec Corporation, R-86M) was used. A solution in which 5 parts by mass of a black pigment was dispersed in 100 parts by mass of the resin for the skin layer synthesized in Synthesis Example 1 and allowed to stand overnight was discharged from a coater, continuously flowed down on the release paper, and adjusted to a thickness of 50 μm with an application roll. It was passed through a dryer at 120 °C to form a urethane layer as the skin layer. Next, the raw materials used in Example 1 were continuously mixed with a mixing head at a temperature of 40 °C so as to have the same composition ratio as in Example 1, continuously flowed down on the release paper, and adjusted to a thickness of 250 μm with an application roll. It was passed through a dryer at 120 °C to form a urethane layer as the adhesive layer. Next, it was laminated using a base fabric (a knitted fabric made of polyester fibers) with a thickness of 600 μm and a pressure roll, wound up using a winding roll, and aged at 50 °C for 1 week. The release paper was removed to obtain a synthetic leather composed of a polyurethane laminate. The physical property evaluation results of the synthetic leather are shown in Table 5.

[0162] [Examples 22 to 37] A synthetic leather composed of a polyurethane laminate was obtained in the same manner as in Example 21, except that the type of the curable composition serving as the adhesive layer was the composition shown in Table 5. The obtained synthetic leather was evaluated, and the results are shown in Table 5.

[0163] [Comparative Examples 7 to 12] A synthetic leather composed of a polyurethane laminate was obtained in the same manner as in Example 20, except that the type of the curable composition to be the subsequent layer was the composition shown in Table 5. The obtained synthetic leather was evaluated, and the results are shown in Table 5.

[0164]

Table 5

Industrial Applicability

[0165] The curable composition of the present invention is excellent in the balance of physical properties such as flexibility, chemical resistance, low-temperature characteristics, heat resistance, and touch feeling, and can be used for an environment-friendly synthetic leather with less solvent used.

Explanation of Symbols

[0166] 1 Release paper 2 Epidermal layer 3 Adhesive layer 4 Base material (woven fabric) 5 Coating machine (epidermal layer) 6 Mixing head (adhesive layer) 7 Sheet structure (dry synthetic leather product) 8 Coating roll 9 Pressing roll 10 Take-up roll 11 Dryer

Claims

1. Component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, Component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, Component (c): a polyether polyol, Component (d): a polyester polyol, and Component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, which comprises a curable composition, wherein the total amount of the component (a) and the component (b) is 30% by mass to 70% by mass based on the total amount of all polyol components in the composition.

2. Component (f): an isocyanate group-terminated prepolymer containing units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, the curable composition according to claim 1.

3. Component (f): an isocyanate group-terminated prepolymer having as constituent units units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, and all components among the component (a), the component (b), the component (c) and the component (d) that are not included in the constituent units of the component (f), which comprises a curable composition, wherein the total amount of the units derived from component (a) and the units derived from component (b) in the constituent units of the component (f) and the total amount of the component (a) and the component (b) is 30% by mass to 70% by mass based on the total amount of all polyol components in the composition.

4. ​ Component (h): A hydroxyl-terminated prepolymer containing units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, and Among the component (a), the component (b), the component (c), and the component (d), all components not included in the constituent units of the component (h), The component (e), Including, The total amount of the units derived from component (a) and the units derived from component (b) in the constituent units of component (h) and the total amount of component (a) and component (b) is 30% to 70% by mass based on the total amount of all polyol components in the composition. A curable composition.

5. Component (f): An isocyanate group-terminated prepolymer having as constituent units units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, and Component (h): A hydroxyl-terminated prepolymer containing units derived from one or more polyols selected from the group consisting of component (a): a polycarbonate polyol having a hydroxyl value of 40 to 75 mg KOH / g, component (b): a polycarbonate polyol having a hydroxyl value of 100 to 280 mg KOH / g, component (c): a polyether polyol, and component (d): a polyester polyol, and units derived from component (e): a polyisocyanate having an average functionality of 2 to 6 per molecule, and Among the component (a), the component (b), the component (c), and the component (d), all components not included in the constituent units of the component (f) and the component (h), Optionally the component (e), Including, The total amount of the units derived from component (a) and the units derived from component (b) in the structural unit of component (f), the total amount of the units derived from component (a) and the units derived from component (b) in the structural unit of component (h), and the total amount of component (a) and component (b) is 30% by mass to 70% by mass based on the total amount of all polyol components in the composition. A curable composition.

6. The curable composition according to claim 1, wherein the polycarbonate polyol of component (a) and component (b) contains a repeating unit represented by the following formula (1) and a terminal hydroxyl group. 【Chemical 1】 (In formula (1), R 1 is a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.)

7. At least 50 mol% of the repeating units represented by the formula (1) contains at least two repeating units selected from the formula (2), the formula (3), and the formula (4). The curable composition according to claim 6. 【Chemical 2】

8. The curable composition according to claim 1, comprising component (g): a chain extender.

9. The curable composition according to claim 1, wherein the hydroxyl value of component (c): polyether polyol and the hydroxyl value of component (d): polyester polyol are each 40 to 75 mgKOH / g.

10. The curable composition according to claim 1, containing an inert organic solvent of 40% by mass or less based on the total amount of the composition.

11. The curable composition according to claim 1, used for an adhesive layer of synthetic leather.

12. A synthetic leather produced from the curable composition according to any one of claims 1 to 11.

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