Synthetic leather

Abstract

A synthetic leather according to this embodiment has: a fibrous substrate; a bonding layer that includes a yellowing-resistant polycarbonate-based polyurethane resin and / or a yellowing polycarbonate-based polyurethane resin; and a surface skin layer that includes a yellowing-resistant polycarbonate-based polyurethane resin and is layered on the fibrous substrate with the bonding layer interposed therebetween. This synthetic leather has superior oleic acid resistance.

Description

[Technical Field]

[0001] This invention relates to synthetic leather, and more specifically, to synthetic leather with excellent resistance to oleic acid. [Background technology]

[0002] Traditionally, synthetic leather has been used in a variety of fields, including vehicle interior materials such as seats and door panels, interior materials such as furniture and chairs, and fashion items such as bags and shoes. Of these, vehicle interior materials are subjected to harsh conditions and therefore require high durability. In particular, for vehicle seats and steering wheels, which often come into direct contact with the human body, durability against sebum secreted from the human body, especially against oleic acid, the main component of sebum, is strongly required.

[0003] For example, Patent Document 1 describes synthetic leather in which a polyurethane resin surface layer is laminated on the surface of a fiber base material via a polyurethane resin adhesive layer. Patent Document 1 also describes that a silicone-modified, non-yellowing polycarbonate-based polyurethane resin is used as the polyurethane resin forming the surface layer, thereby satisfying the oleic acid resistance required for vehicle interior materials. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-31862 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the synthetic leather described in Patent Document 1 has room for improvement in applications requiring higher resistance to oleic acid. Examples of such applications include parts of vehicle interiors that are frequently touched by the human body, especially by hands, such as steering wheels, shift levers, and armrests.

[0006] This invention has been made in view of the current situation, and its purpose is to provide synthetic leather with excellent resistance to oleic acid. [Means for solving the problem]

[0007] A synthetic leather according to an embodiment of the present invention comprises a fibrous base material, an adhesive layer containing a non-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin, and a surface layer containing a non-yellowing polycarbonate polyurethane resin laminated to the fibrous base material via the adhesive layer. [Effects of the Invention]

[0008] According to embodiments of the present invention, it is possible to provide synthetic leather with excellent resistance to oleic acid. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view of synthetic leather according to one embodiment. [Figure 2] This is a schematic cross-sectional view of synthetic leather according to another embodiment. [Figure 3] This is a schematic cross-sectional view of synthetic leather according to another embodiment. [Modes for carrying out the invention]

[0010] The synthetic leather according to this embodiment is formed by laminating an adhesive layer and an epidermis layer on a fibrous substrate. The epidermis layer contains a yellowing-resistant polycarbonate-based polyurethane resin. The adhesive layer contains a yellowing-resistant polycarbonate-based polyurethane resin and / or a yellowing-type polycarbonate-based polyurethane resin. By including such a polyurethane resin in the epidermis layer and the adhesive layer, the intermolecular interactions (hydrogen bonds, van der Waals forces, π-π stacking interactions) of the polyurethane resin are enhanced, and the gaps between molecules become smaller. More specifically, the polycarbonate-based has a stronger intramolecular polarization compared to the polyether-based and polyester-based. Also, the yellowing-resistant type and the yellowing type have an aromatic structure, and intermolecular forces due to the interaction of π electrons between aromatic rings act. Therefore, it is considered that the intermolecular interactions of the polyurethane resin are enhanced. Therefore, the intrusion of oleic acid can be suppressed, and the oleic acid resistance can be improved. Also, at the interface between the epidermis layer and the adhesive layer, the intermolecular interactions of the polyurethane resin are enhanced, and for the same reasons as above, the oleic acid resistance can be improved.

[0011] FIG. 1 schematically shows a cross-sectional structure of a synthetic leather 1 according to an embodiment. In this synthetic leather 1, an epidermis layer 4 is directly laminated on one surface of a fibrous substrate 2 via an adhesive layer 3. Therefore, on one surface of the fibrous substrate 2, the adhesive layer 3 and the epidermis layer 4 are laminated in this order.

[0012] FIG. 2 schematically shows a cross-sectional structure of a synthetic leather 10 according to another embodiment. This synthetic leather 10 is different from the synthetic leather 1 in FIG. 1 in that the epidermis layer 4 has a two-layer structure. Therefore, in the example of FIG. 2, on one surface of the fibrous substrate 2, the adhesive layer 3, the epidermis layer 41, and the epidermis layer 42 are laminated in this order.

[0013] Figure 3 schematically shows a cross-sectional structure of a synthetic leather 100 according to another embodiment. In this synthetic leather 100, an anchor coat layer 5 and a foam layer 6 are provided between an adhesive layer 3 and an epidermis layer 4, and a protective layer 7 is provided on the epidermis layer 4. Therefore, in the example of Figure 3, the adhesive layer 3, the anchor coat layer 5, the foam layer 6, the epidermis layer 4, and the protective layer 7 are laminated in this order on one surface of the fibrous substrate 2.

[0014] In the examples of Figures 1 to 3, the front surface of the synthetic leather is flat, but unevenness may be provided in consideration of the design. Here, the front surface of the synthetic leather means the surface (design surface) that is visible to the eye during use among the front and back of the synthetic leather.

[0015] In the present embodiment, the fibrous substrate is not particularly limited, and examples thereof include fabrics such as woven fabrics, knitted fabrics, non-woven fabrics, and leather (including floor leather). Among them, from the viewpoint of good sewing property of the obtained synthetic leather, a knitted fabric or a woven fabric is preferable, and a knitted fabric is more preferable. For the fabric, a conventionally known solvent-based or solvent-free (including water-based) polymer compound (for example, polyurethane resin and its copolymer, and polyvinyl chloride resin) may be applied or impregnated, and dry coagulation or wet coagulation may be performed. The fibrous substrate may be colored with a dye or a pigment.

[0016] The thickness of the fibrous substrate is not particularly limited, and from the viewpoints of abrasion resistance, strength, and touch feeling, it is preferably 0.9 to 1.3 mm, and more preferably 1.0 to 1.2 mm. The above thickness of the fibrous substrate is the thickness of the fibrous substrate before laminating the adhesive layer and the epidermis layer, but the thickness of the fibrous substrate in the laminated synthetic leather may be set within the same range.

[0017] The synthetic leather according to the present embodiment is formed by laminating an adhesive layer containing a non-yellowing type polycarbonate-based polyurethane resin and / or a yellowing type polycarbonate-based polyurethane resin as a resin layer and an epidermis layer containing a non-yellowing type polycarbonate-based polyurethane resin on the above-mentioned fibrous substrate.

[0018] Here, non-yellowing polycarbonate polyurethane resins and yellowing polycarbonate polyurethane resins are polycarbonate polyurethane resins that have aromatic rings in their molecules, and are different from non-yellowing polycarbonate polyurethane resins that do not have aromatic rings.

[0019] Examples of non-yellowing polycarbonate-based polyurethane resins include (A1) and (A2) listed below. (A1) Obtained by reaction between a polycarbonate polyol component and a non-yellowing polyisocyanate component. (A2) A product obtained by reaction of a polycarbonate polyol with a yellowing polyisocyanate component and containing an ultraviolet absorber and / or a light stabilizer. Polycarbonate-based polyurethane resins that are resistant to yellowing may contain other polyol components or polyisocyanate components as copolymerization components, as long as this does not impair their properties.

[0020] Examples of yellowing polycarbonate-based polyurethane resins include those obtained by the reaction of (B) a polycarbonate polyol component and a yellowing polyisocyanate component, and which do not contain ultraviolet absorbers and / or light stabilizers. The yellowing polycarbonate-based polyurethane resin may contain other polyol components or polyisocyanate components as copolymer components, as long as this does not impair its effect.

[0021] Examples of polycarbonate polyol components include at least one polyalkylene carbonate diol selected from the group consisting of polyethylene carbonate diol, polybutylene carbonate diol, and polyhexamethylene carbonate diol.

[0022] Aromatic aliphatic polyisocyanates are used as non-yellowing polyisocyanate components. Aromatic aliphatic polyisocyanates are polyisocyanates in which the isocyanate group is not directly bonded to the aromatic ring. Examples include aromatic aliphatic diisocyanates such as xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI), and these may be used individually or in combination of two.

[0023] Aromatic polyisocyanates are used as the yellowing-type polyisocyanate components. Aromatic polyisocyanates are polyisocyanates in which an isocyanate group is directly bonded to an aromatic ring. Examples include aromatic diisocyanates such as phenylenediisocyanate, toluene diisocyanate (TDI), 4,4'- or 2,4'-diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate, and any one or two or more of these may be used in combination. Among these, TDI and / or MDI are preferred from the viewpoint of improving resistance to oleic acid.

[0024] Examples of UV absorbers include "Tinuvin326" and "Tinuvin400" (both manufactured by BASF Japan Ltd.).

[0025] Examples of light stabilizers include "Tinuvin 144" and "Tinuvin 5866" (both manufactured by BASF Japan Ltd.).

[0026] Examples of the non-yellowing polycarbonate polyurethane resins mentioned in (A1) above include those obtained by reacting a polycarbonate polyol component with a non-yellowing polyisocyanate component and a low molecular weight chain extender. Alternatively, a urethane polycarbonate polyol prepolymer, obtained by reacting a polycarbonate polyol component with a non-yellowing polyisocyanate component, may be obtained by reacting this prepolymer with a non-yellowing polyisocyanate component (urethane curing agent). Furthermore, a non-yellowing urethane polyisocyanate prepolymer, obtained by reacting a polycarbonate polyol component with a non-yellowing polyisocyanate component, may be obtained by reacting this prepolymer with a polycarbonate polyol component.

[0027] Examples of the non-yellowing polycarbonate-based polyurethane resins described in (A2) above include those obtained by reacting a polycarbonate polyol component, a yellowing-type polyisocyanate component, a low molecular weight chain extender, and an ultraviolet absorber or light stabilizer. Alternatively, a urethane polycarbonate polyol prepolymer obtained by reacting a polycarbonate polyol component with a yellowing-type polyisocyanate component may be obtained by reacting a yellowing-type polyisocyanate component (urethane curing agent) with an ultraviolet absorber or light stabilizer. Alternatively, a yellowing-type urethane polyisocyanate prepolymer obtained by reacting a polycarbonate polyol component with a yellowing-type polyisocyanate component may be obtained by reacting a polycarbonate polyol component with an ultraviolet absorber or light stabilizer.

[0028] Examples of the yellowing polycarbonate-based polyurethane resin described in (B) above include those obtained by reacting a polycarbonate polyol component with a yellowing polyisocyanate component and a low molecular weight chain extender. Alternatively, it may be obtained by reacting a urethane polycarbonate polyol prepolymer, which is obtained by reacting a polycarbonate polyol component with a yellowing polyisocyanate component, with a yellowing polyisocyanate component (urethane curing agent). Alternatively, it may be obtained by reacting a yellowing urethane polyisocyanate prepolymer, which is obtained by reacting a polycarbonate polyol component with a yellowing polyisocyanate component, with a polycarbonate polyol component.

[0029] Examples of the low molecular weight chain extenders mentioned above include compounds having at least two active hydrogen atoms, such as at least one selected from the group consisting of aliphatic diols, alicyclic diols, aliphatic diamines, alicyclic diamines, and hydrazine derivatives.

[0030] As described above, a polycarbonate-based polyurethane resin that does not yellow easily is used as the resin that constitutes the epidermal layer. By using this resin, the intermolecular interactions of the polyurethane resin (hydrogen bonds, van der Waals forces, π-π stacking interactions) are enhanced, and the gaps between molecules become smaller. Therefore, the penetration of oleic acid can be suppressed, and oleic acid resistance can be improved.

[0031] The form of the non-yellowing polycarbonate-based polyurethane resin for the surface layer is not particularly limited and can be appropriately selected according to the application. For example, it may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. Preferably, from the viewpoint of film-forming properties, it is a solvent-based one-component type.

[0032] The surface layer consists of a resin mainly composed of a low-yellowing polycarbonate polyurethane resin. The resin forming the surface layer may consist solely of a low-yellowing polycarbonate polyurethane resin, but may also contain other resins such as polyurethane resins to the extent that it does not impair the effect. For example, it is preferable that 60% by mass or more, more preferably 80% by mass or more, of the resin forming the surface layer is a low-yellowing polycarbonate polyurethane resin.

[0033] The epidermal layer may contain additives such as crosslinking agents and colorants as needed. The crosslinking agent is incorporated into the resin by reaction to form a crosslinked structure. Examples of crosslinking agents include isocyanate-based crosslinking agents and carbodiimide-based crosslinking agents. Among these, isocyanate-based crosslinking agents are preferred. By adding an isocyanate-based crosslinking agent, the crosslinking density of the resin can be increased, thereby improving oleic acid resistance. Ethanol resistance can also be imparted.

[0034] Examples of isocyanate-based crosslinking agents include aromatic polyisocyanates such as phenylene diisocyanate, TDI, MDI, and naphthalene diisocyanate; aromatic aliphatic polyisocyanates such as XDI and TMXDI; aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate; and alicyclic polyisocyanates. Among these, it is preferable from the viewpoint of resistance to yellowing to change to use at least one selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic aliphatic diisocyanates. It is preferable from the viewpoint of resistance to oleic acid and ethanol to use at least one selected from the group consisting of aromatic diisocyanates and aromatic aliphatic diisocyanates.

[0035] The content of isocyanate-based crosslinking agents in the epidermal layer is not particularly limited. For example, it may be 0.1 to 15% by mass, 1 to 10% by mass, or 3 to 10% by mass in terms of solid content in the resin composition for the epidermal layer used to form the epidermal layer. By limiting the isocyanate-based crosslinking agent content to 15% by mass or less, it is possible to prevent the texture from becoming rough and hard.

[0036] The coloring agent is not particularly limited, and examples include conventionally known pigments, dyes, etc. Adding a coloring agent can improve the design. The content of the coloring agent in the surface layer is not particularly limited, but is preferably 20 to 38% by mass in terms of solid content in the resin composition for the surface layer, more preferably 25 to 35% by mass, and even more preferably 28 to 32% by mass. When the coloring agent content is 20% by mass or more, the surface color of the resulting synthetic leather becomes darker, and discoloration of the polyurethane resin due to heat and light can be suppressed. When the coloring agent content is 38% by mass or less, the friction fastness is not impaired.

[0037] In this embodiment, the surface layer may be formed as one layer or as two or more layers. In Figure 2, the surface layer is formed as two layers. In this case, the form of the non-yellowing polycarbonate polyurethane resin forming the first surface layer (surface layer 42) on the front side is preferably a solvent-based one-component type from the viewpoint of film formation. The form of the non-yellowing polycarbonate polyurethane resin forming the second surface layer (surface layer 41) on the adhesive layer side is preferably a water-based one-component type from the viewpoint of low environmental impact and less likely to dissolve the first surface layer during lamination (when applying multiple layers of resin liquid), and a solvent-based one-component type from the viewpoint of film formation.

[0038] Furthermore, the surface layer may be formed in three or more layers. In that case, the form of the non-yellowing polycarbonate polyurethane resin forming the first surface layer is preferably a solvent-based one-component type from the viewpoint of film-forming properties. The form of the non-yellowing polycarbonate polyurethane resin forming the surface layer in contact with the adhesive layer is preferably a water-based one-component type from the viewpoint of having a low environmental impact and being less likely to dissolve existing layers during lamination (overcoating), and a solvent-based one-component type from the viewpoint of film-forming properties. The form of the non-yellowing polycarbonate polyurethane resin forming the surface layer existing between the first surface layer and the surface layer in contact with the adhesive layer may be the same as that of the "surface layer in contact with the adhesive layer," that is, a solvent-based or water-based type may be selected depending on the purpose.

[0039] Furthermore, if there are two or more epidermal layers, the content of the crosslinking agent and colorant in the epidermal layers mentioned above only needs to satisfy the above-mentioned numerical range in the outermost epidermal layer (epidermal layer 42 in Figure 2) or the epidermal layer in contact with the protective layer.

[0040] In one embodiment, the thickness of the epidermal layer is preferably 17 to 80 μm, more preferably 20 to 70 μm, and even more preferably 25 to 60 μm. A thickness of 17 μm or more enhances the effect of improving resistance to oleic acid. A thickness of 80 μm or less prevents the resulting synthetic leather from becoming rough and hard. If the epidermal layer is formed from multiple layers, the total thickness of the multiple epidermal layers should satisfy the above numerical range.

[0041] As the resin constituting the adhesive layer, either or both of the following are used: a non-yellowing polycarbonate polyurethane resin and a yellowing polycarbonate polyurethane resin. By using this resin, the intermolecular interactions of the polyurethane resin (hydrogen bonds, van der Waals forces, π-π stacking interactions) are increased, and the gaps between molecules become smaller. Therefore, the penetration of oleic acid can be suppressed, and oleic acid resistance can be improved. Furthermore, by using a non-yellowing polycarbonate polyurethane resin for the surface layer and a non-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin for the adhesive layer, the surface layer and the adhesive layer have an aromatic structure. Therefore, the intermolecular interactions of the polyurethane resin are also increased at the interface between the surface layer and the adhesive layer, and for the same reasons as above, oleic acid resistance can be improved.

[0042] The form of the non-yellowing polycarbonate polyurethane resin for the adhesive layer is not particularly limited and can be appropriately selected depending on the application. For example, it may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. Preferably, from the viewpoint of adhesion between the surface layer and the fibrous substrate, it is a solvent-based two-component curing type.

[0043] The adhesive layer consists of a resin mainly composed of a low-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin. The resin forming the adhesive layer may consist only of a low-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin, but it may also contain other resins such as polyurethane resins to the extent that it does not impair the effect. For example, it is preferable that 60% by mass or more, more preferably 80% by mass or more of the resin forming the adhesive layer is a low-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin.

[0044] The adhesive layer may contain additives such as crosslinking agents, colorants, catalysts, and flame retardants, as needed. Examples of crosslinking agents include isocyanate-based crosslinking agents and carbodiimide-based crosslinking agents. Examples of colorants include pigments and dyes. Examples of catalysts include amine-based catalysts and organotin compounds.

[0045] In one embodiment, the thickness of the adhesive layer is preferably 100 to 200 μm, and more preferably 145 to 195 μm. A thickness of 100 μm or more allows for good resistance to oleic acid and conceals the fibrous substrate, resulting in good design aesthetics. A thickness of 200 μm or less prevents the resulting synthetic leather from becoming rough and hard.

[0046] The thickness of the adhesive layer is preferably greater than the thickness of the surface layer. This results in a better texture. Furthermore, the thickness of the adhesive layer is preferably greater than the thickness of the foam layer, and also preferably greater than the thickness of the anchor coat layer. This results in a better texture.

[0047] While not particularly limited, the adhesive layer is preferably a non-porous layer. Regarding other resin layers, it is also preferable that the resin layers other than the foamed layer—namely, the surface layer, anchor coat layer, and protective layer—are all non-porous layers.

[0048] In this embodiment, a foam layer may be provided between the epidermal layer and the adhesive layer as needed, or a foam layer and an anchor coat layer may be provided.

[0049] The foam layer is laminated on the back surface of the epidermis (i.e., beneath the epidermis). The foam layer is added to the synthetic leather's resin layer to increase its thickness, making it more difficult for oleic acid to penetrate and further improving its resistance to oleic acid. Because it is a foam layer, it does not impair the texture even if the resin layer is thick. In addition, the foam layer can also provide a cooling sensation to the touch.

[0050] The anchor coat layer is provided between the foam layer and the adhesive layer. In other words, the anchor coat layer is laminated on the back surface of the foam layer (i.e., underneath the foam layer) and is provided to enhance the adhesion between the foam layer and the adhesive layer.

[0051] The foam layer and anchor coat layer preferably contain polyurethane resin from the viewpoint of improving adhesion. The polyurethane resin contained in the foam layer and anchor coat layer is preferably a polycarbonate-based polyurethane resin. More preferably, the same polyurethane resin as the surface layer is used. That is, from the viewpoint of improving oleic acid resistance, the foam layer and anchor coat layer preferably contain a polycarbonate-based polyurethane resin that does not yellow easily, and preferably consist of a resin mainly composed of a polycarbonate-based polyurethane resin that does not yellow easily, similar to the surface layer. By using a polycarbonate-based polyurethane resin that does not yellow easily, the intermolecular interactions of the polyurethane resin (hydrogen bonds, van der Waals forces, π-π stacking interactions) are increased, and the gaps between molecules become smaller. Therefore, the penetration of oleic acid can be suppressed, and oleic acid resistance can be improved. In addition, the intermolecular interactions of the polyurethane resin are also increased at the interfaces of each layer, and for the same reasons as above, oleic acid resistance can be improved.

[0052] The form of the non-yellowing polycarbonate polyurethane resin used in the foam layer and anchor coat layer is not particularly limited and can be appropriately selected depending on the application. For example, it may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. Considering the preferred form of hollow fine particles added to the foam layer (hollow fine particles having an outer shell made of thermoplastic resin), a water-based one-component type is preferred.

[0053] In addition to the resin, the foam layer and anchor coat layer may contain additives such as foaming agents, hollow fine particles, crosslinking agents, leveling agents, thickeners, pH adjusters, defoaming agents, and colorants, as needed. Examples of crosslinking agents include isocyanate-based crosslinking agents and carbodiimide-based crosslinking agents. As for the isocyanate-based crosslinking agent, it is preferable to use at least one selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic aliphatic diisocyanates, similar to the epidermal layer.

[0054] The means for forming pores in the foamed layer are not particularly limited, and known methods can be used. For example, physical foaming by mechanical stirring, chemical foaming by adding a foaming agent, or foaming (forming occlusions) by adding hollow microparticles can be used. Alternatively, occlusions may be formed by wet coating of polyurethane resin, followed by covering the layer surface with a non-porous layer. Preferably, pore formation by adding hollow microparticles is preferred from the viewpoint of being easy to adjust the shape and size of the pores and the foaming ratio.

[0055] Hollow microparticles are spherical particles in which tiny internal voids are covered with a coating (called an outer shell or outer wall) made of various materials. Preferably, they are those that do not undergo volume expansion even when heat-treated. Using such hollow microparticles minimizes volume fluctuations in the foamed layer during manufacturing, reducing variations in quality. Furthermore, it prevents the resin surrounding the hollow microparticles from being stretched and thinned, thus preventing damage to its oleic acid resistance.

[0056] Various types of hollow microparticles that satisfy the above conditions can be used. For example, organic hollow microparticles having an outer shell made of thermosetting resins such as phenolic resin, epoxy resin, or urea resin, or thermoplastic resins such as acrylic resin or polyvinyl chloride resin can be used. Alternatively, inorganic hollow microparticles having an outer shell made of glass, shirasu, silica, alumina, or carbon can also be used. Furthermore, organic hollow microparticles whose surface is coated with inorganic fine powder such as calcium carbonate, talc, or titanium dioxide can also be used. Among these, organic hollow microparticles having an outer shell made of thermoplastic resin, or organic hollow microparticles whose surface is coated with inorganic fine powder, are preferred from the viewpoint of heat resistance, abrasion resistance, and strength.

[0057] A preferred embodiment of hollow microparticles having an outer shell made of a thermoplastic resin is typically a microencapsulated blowing agent that has been pre-foamed. The microencapsulated blowing agent itself contains a volatile blowing agent, such as a low-boiling-point hydrocarbon, within an outer shell made of a thermoplastic resin that can be softened and expanded by heat treatment. In one embodiment, the microencapsulated blowing agent may be used as is, or it may be used as a pre-foamed product obtained by pre-foaming. Among these, the pre-foamed product is preferred from the viewpoint of heat resistance.

[0058] In one embodiment, the thickness of the foamed layer is preferably 70 to 170 μm. A thickness of 70 μm or more allows for good resistance to oleic acid. A thickness of 170 μm or less allows for good processability.

[0059] In one embodiment, the thickness of the anchor coat layer is preferably 17 to 27 μm. A thickness of 17 μm or more prevents the outer shell of the hollow fine particles in the foam layer from dissolving with the solvent in the adhesive layer. A thickness of 27 μm or less prevents the texture from becoming rough and hard.

[0060] In this embodiment, a protective layer may be provided on the surface layer. By providing a protective layer on the surface layer, the abrasion resistance of the resulting synthetic leather can be improved. The protective layer preferably contains a polycarbonate-based polyurethane resin.

[0061] The form of the polycarbonate-based polyurethane resin for the protective layer is not particularly limited and can be appropriately selected depending on the application. For example, it may be solvent-free, hot-melt, solvent-based, or water-based, and may be one-component or two-component curing type. From the viewpoint of abrasion resistance, texture, and feel, a water-based one-component type is preferred.

[0062] The polycarbonate-based polyurethane resin that constitutes the protective layer can be obtained, for example, by reacting a polycarbonate polyol component, a polyisocyanate component, and a low molecular weight chain extender.

[0063] Here, as the polycarbonate polyol component, for example, at least one polyalkylene carbonate diol selected from the group consisting of polyethylene carbonate diol, polybutylene carbonate diol, and polyhexamethylene carbonate diol can be used.

[0064] As the polyisocyanate component, at least one organic polyisocyanate selected from, for example, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, aromatic polyisocyanates, etc., can be used. However, from the viewpoint of abrasion resistance and light resistance, at least one selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic aliphatic diisocyanates is preferred, and among these, at least one selected from the group consisting of HDI, XDI, and IPDI is preferred.

[0065] Furthermore, examples of low molecular weight chain elongators include compounds having at least two active hydrogen atoms, such as at least one selected from the group consisting of aliphatic diols, alicyclic diols, aliphatic diamines, alicyclic diamines, and hydrazine derivatives.

[0066] The protective layer may contain a resin other than a polycarbonate-based polyurethane resin, and in addition to the resin, additives such as a crosslinking agent, a leveling agent, a matting agent, and a coloring agent may be contained as required. Examples of the crosslinking agent include an isocyanate-based crosslinking agent and a carbodiimide-based crosslinking agent. As the isocyanate-based crosslinking agent, an aliphatic polyisocyanate and / or an alicyclic polyisocyanate are preferable. Examples of the matting agent include inorganic particles such as silica. When a matting agent is added to the protective layer, the content of the matting agent in the protective layer is not particularly limited, but may be 3 to 40% by mass in terms of solid content.

[0067] In one embodiment, the thickness of the protective layer is preferably 6 to 16 μm. When the thickness is 6 μm or more, good abrasion resistance can be achieved. When the thickness is 16 μm or less, it is possible to prevent the texture from becoming rough and hard.

[0068] The synthetic leather according to this embodiment preferably has a dark surface color (that is, the color of the front side). By being a dark color, discoloration of the polycarbonate-based polyurethane resin with low yellowing resistance due to heat or light can be suppressed (made less noticeable).

[0069] Specifically, L * a * b * In the L * a * b color system, it is preferably 27 or less, and more preferably 25 or less. L * a * b * The color system is a color display method standardized by the International Commission on Illumination (CIE 1976) and also defined in JIS (JIS Z 8781-4:2013). Incidentally, L * can be obtained by measuring L * at any three locations using an integrating sphere spectrophotometer (Color-i5, manufactured by X-Rite) and calculating the average value of these.

[0070] The lamination of the surface layer and adhesive layer of synthetic leather is carried out, for example, by the following method: A resin liquid (resin composition for the surface layer) for forming the surface layer is applied to a release substrate and then dry-coagulated to form the surface layer. Subsequently, a resin liquid (resin composition for the adhesive layer) for forming the adhesive layer is applied to the surface layer, and while it is still viscous, it is pressed onto one side of a fibrous substrate to laminate the adhesive layer and the surface layer. The surface of the release substrate may be flat, or it may have irregularities such as a grain pattern.

[0071] When a foamed layer is to be formed, the lamination is carried out, for example, by the following method: A resin liquid for forming the surface layer is applied to a release substrate and then dry-coagulated to form the surface layer. Subsequently, a resin liquid for forming the foamed layer (resin composition for foamed layer) is applied to the surface layer and dry-coagulated to form the surface layer and foamed layer on the release substrate. After that, a resin liquid for forming the adhesive layer is applied to the foamed layer, and while it is still viscous, it is pressed onto one side of a fibrous substrate to laminate the adhesive layer, foamed layer, and surface layer.

[0072] When an anchor coat layer is provided, its lamination is carried out in the same manner as the foam layer. That is, after forming the surface layer and foam layer on the release substrate, and before applying the resin liquid that forms the adhesive, a resin liquid (resin composition for the anchor coat layer) for forming the anchor coat layer is applied to the foam layer, and then dry solidification is performed to form the surface layer, foam layer, and anchor coat layer on the release substrate.

[0073] Furthermore, when a protective layer is provided, its lamination is carried out, for example, by the following method: After laminating the adhesive layer and the surface layer onto the fibrous substrate by the method described above, a resin liquid (resin composition for protective layer) for forming the protective layer is applied to the surface layer and dry-coagulated to form the protective layer.

[0074] The application method for each resin liquid can be any known method such as knife coating, roll coating, gravure coating, or spray coating. The resin liquid may be applied in one application in the desired amount, or it may be applied in two or more applications in the desired amount.

[0075] The uses of the synthetic leather according to this embodiment are not particularly limited. For example, it can be used as interior material for various vehicles, including car seats, headliners, dashboards, door panels, steering wheels, shift levers, armrests, and other automotive interior materials. Other uses include interior applications such as upholstery for sofas and chairs, and fashion applications such as bags and shoes. [Examples]

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0077] Each evaluation item was assessed according to the following method.

[0078] [Oleic acid resistant] (1) Changes in appearance after oleic acid treatment A test specimen measuring 100 mm in height and 160 mm in width was taken. The test specimen was attached to the entire surface of a cardboard backing of the same size and thickness of 1.0 mm (white cardboard No. 12, manufactured by Workup Co., Ltd.) using double-sided tape (No. 7570, manufactured by Teraoka Seisakusho Co., Ltd.). A paper cloth (Wipe-All X50, manufactured by Nippon Paper Crecia Co., Ltd.) cut to 50 mm vertically and 120 mm horizontally was placed on the surface of the test specimen, and 3.5 g of oleic acid (CAS number: 112-80-1) was applied through the paper cloth and left for 5 minutes. Then, a new paper cloth cut to 50 mm vertically and 120 mm horizontally was placed on top of the paper cloth on the test specimen. The test specimen was placed in the center of a stainless steel pad with a lid (EBM18-8 seasoning container with lid, manufactured by Ebematsu Shoji Co., Ltd.), and the stainless steel pad was left to stand (heat treat) for a predetermined time in a forced-air constant-temperature drying oven (DRS420DA, manufactured by Advantec Toyo Co., Ltd.) set to a predetermined temperature. After heat treatment according to the heat treatment conditions described below, the stainless steel pads were removed from the forced-air constant-temperature drying oven and left at room temperature for 1 hour. Then, the paper wipes were removed from the test pieces, and new paper wipes were pressed onto them to remove excess oleic acid. The surface appearance of the resulting oleic acid-treated test pieces was observed visually. Those with no abnormalities in the surface appearance were deemed acceptable, while those with abnormalities (such as peeling of the coating) were deemed unacceptable. <Heat treatment conditions> ·80℃×30 hours ·90℃×30 hours ·100℃×12 hours ·100℃×24 hours ·100℃×30 hours

[0079] (2) Abrasion resistance after oleic acid treatment The test specimens, after the oleic acid treatment described above, were cut with the backing still attached to a size of 50 mm vertically and 120 mm horizontally. The test specimens were attached to the table of a Beslick abrasion tester (manufactured by GIULIANI TECHNOLOGIE srl) using double-sided tape (rubber-specific double-sided tape, 775, manufactured by Teraoka Seisakusho Co., Ltd.). A 1.5 cm square piece of felt (model 701, manufactured by Swissatest Testmaterialien AG) was attached to the tip of the abrasive (a 1.5 cm square flat plate) using double-sided tape (rubber-specific double-sided tape, 775, manufactured by Teraoka Seisakusho Co., Ltd.). The surface pressure on the surface of the test specimen was 444 g / cm². 2 (4.5N / cm 2 With a load of 9.8N (1000gf) applied to the friction element, the stroke was set to 37.5mm, and the felt was rubbed against the test piece at 40 cycles (back and forth) per minute. After 1000 cycles of friction, the surface appearance of the test piece was observed. The test piece was evaluated according to the following evaluation criteria, and grade 4 or higher was considered a pass. <Evaluation Criteria> Grade 5: No abnormalities (paint film peeling, tearing) are observed at all. Grade 4: Slight abnormalities (paint film peeling, tearing) are observed but are not noticeable. Grade 3: Abnormalities (paint film peeling, tearing) are observed. Grade 2: Somewhat significant abnormalities (paint film peeling, tearing) are observed. Grade 1: Significant abnormalities (paint film peeling, tearing) are observed.

[0080] [Yellowing Resistant] A test specimen measuring 70 mm in width and 200 mm in length was taken. The test specimen was mounted on a high-temperature fade meter (SUGA Test Instruments Co., Ltd., UV fade meter U48) and irradiated on the resin layer side of the specimen for 400 hours. The irradiation area was 45 mm x 65 mm, and each test specimen was irradiated at three locations. At that time, the high-temperature fade meter was set to one carbon arc lamp (luminous intensity configuration according to JIS L0842:2004), a distance of 250 mm from the light source to the test specimen, an internal temperature of 55~65°C, a black panel temperature of 83±3°C on the sample stand, a relative humidity of 30~50%, an arc voltage of 120~145 V, a current of 15~17 A, and a sample rotation speed of 3~4 times / min. After irradiation, the surface appearance of the irradiated area of ​​the test specimen was observed and compared with the unirradiated area of ​​the same sample, and the degree of discoloration was measured using a grayscale for discoloration (JIS L0804) as the color difference ΔE. * ab Colorimetric measurements were taken using a colorimeter based on the following criteria. The samples were evaluated according to the evaluation standards below, with grade 4 or higher being considered acceptable. Note that evaluations between grades in JIS L0804 (e.g., grades 3-4) are shown as evaluations between grades (e.g., grades 3-4). (Evaluation Criteria) Grade 5: Color discoloration is equivalent to that of standard gray color chart No. 5. Grade 4: Color discoloration is equivalent to that of standard gray color chart No. 4. Grade 3: Color discoloration is equivalent to that of standard gray color chart No. 3. Grade 2: Color discoloration is equivalent to that of standard gray color chart No. 2. Grade 1: Color discoloration is equivalent to that of standard gray color chart No. 1.

[0081] [Texture] The panelists conducted a sensory evaluation based on touch, and the results were judged according to the following criteria. A score of B or higher is considered a passing grade. (Judgment criteria) A: It has a soft texture. B: The texture is somewhat rough and hard. C: The texture is rough and hard.

[0082] [Example 1] <Fiber-based material> Using an 18G circular knitting machine, a circular knitted fabric was knitted in a mock rod structure using 330dtex / 96f polyester processed yarn as the face and connecting yarns, and 330dtex / 96f polyester processed yarn as the backing yarn. The resulting circular knitted fabric was washed and dried to obtain a fibrous base material (weight 480g / m²). 2 A thickness of 1.0 mm was obtained.

[0083] <Formulation 1: Resin composition for the epidermal layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin CU-9450NL, solvent-based one-component type, solid content 30% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 30 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The viscosity was adjusted using a DMF (Direct Mold Filter) to 3,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C).

[0084] <Formulation 2: Resin composition for foamed layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (DIC Corporation, Hydran WLI-620AR, water-based single-component type, solid content 40% by mass) • Hollow particles: Pre-foamed microcapsules: 25 parts by mass (Manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd., Matsumoto Microsphere FN-100S (pre-foamed by heat treatment), average particle size 50 μm, solid content 100% by mass, powder, outer shell: acrylonitrile polymer, inner contents: isopentane, pre-foamed product) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM XL-50, solids content 50% by mass) • Leveling agent: Silicone-based leveling agent: 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM Fluid H, solids content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by LANXESS Corporation, EUDERM Black BN, solids content 25% by mass) Preparation method: The above-mentioned chemicals were mixed and stirred to prepare a resin composition for the foamed layer. The viscosity of the obtained resin composition for the foamed layer was 5,000 mPa·s (B-type viscometer, rotor: No. 4, 12 rpm, 23°C).

[0085] <Formulation 3: Resin composition for anchor coat layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (DIC Corporation, Hydran WLI-620AR, water-based single-component type, solid content 40% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM XL-50, solids content 50% by mass) • Leveling agent: Silicone-based leveling agent: 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM Fluid H, solids content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by LANXESS Corporation, EUDERM Black BN, solids content 25% by mass) Preparation method: The above-mentioned agents were mixed and stirred to prepare a resin composition for the anchor coat layer. The viscosity of the obtained resin composition for the anchor coat layer was 5,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C).

[0086] <Formulation 4: Resin composition for adhesive layer> (1) Production example 1: Polyisocyanate solution • Polyol component: Polycarbonate-based polyol: 20 parts by mass (Manufactured by Ube Industries, Ltd., ETERNACOLL UH-200, solid content 100% by mass) • Diisocyanate component: XDI system: 9.02 parts by mass (Manufactured by Mitsui Chemicals, Inc., Takenate 500, solid content 100% by mass) Preparation method: The above ingredients were mixed and heated to 25-80°C at a rate of 1°C / min. The mixture was stirred at 80°C for 60 minutes to complete the urethane reaction and obtain a polyisocyanate solution. (2) Manufacturing example 2: Polyol solution • Main component: Polycarbonate-based polyol: 30 parts by mass (Manufactured by Ube Industries, Ltd., ETERNACOLL UH-100, solid content 100 parts by mass) • Catalyst: Amine-based catalyst: 2 parts by mass (Manufactured by Tosoh Corporation, TEDA-L33, solid content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) Flame retardant: Phosphorus-based flame retardant: 20 parts by mass (Manufactured by Clariant Japan Co., Ltd., PEKOFLAM STC powder, solid content 100% by mass) ·DMF: 90 parts by mass Preparation method: The viscosity was adjusted using a DMF (Direct Mold Filter) to 10,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C). (3) 29.02 parts by mass of the polyisocyanate solution from Production Example 1 and 152 parts by mass of the polyol solution from Production Example 2 were weighed and mixed by stirring to obtain a resin composition for adhesive layers containing a two-component curable, non-yellowing polycarbonate-based polyurethane resin.

[0087] <Formulation 5: Resin composition for protective layer> • Main component: Water-based polycarbonate polyurethane resin: 90 parts by mass (BAYDERM Finish 61UD, water-based one-component type, solid content 35% by mass) • Matting agent: Silica-containing water-based polycarbonate polyurethane resin: 10 parts by mass (HYDRHOLAC UD-2, solid content 25% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 1 part by mass (AQUADERM XL-50, solid content 50% by mass) • Leveling agent: Silicone-based leveling agent: 1 part by mass (AQUADERM Fluid H, solid content 100% by mass) ·Water: 20 parts by mass All ingredients, except for water, are manufactured by Lanxess Corporation. Preparation method: The above-mentioned chemicals were mixed and stirred to prepare a protective layer resin composition. The viscosity of the obtained protective layer resin composition was 200 mPa·s (B-type viscometer, rotor: No. 1, 12 rpm, 23°C).

[0088] <Manufacturing of synthetic leather> The resin composition for the epidermal layer, prepared according to Formulation 1 described above, was applied to a release paper (ARX196M, manufactured by Asahi Roll Co., Ltd.) having a textured, uneven surface using a comma coater at a rate of 110 g / m². 2 The material was applied in a sheet-like form and then dried in a dryer at 100°C for 3 minutes, followed by 130°C for 3 minutes to form an epidermal layer. The thickness of the resulting epidermal layer was 27 μm.

[0089] Next, the resin composition for the foamed layer, prepared according to Formulation 2 described above, is applied to the surface of the surface layer formed on the release paper using a comma coater at a rate of 90 g / m². 2 The material was applied in a sheet-like form and treated in a dryer at 100°C for 3 minutes to form a foamed layer. The thickness of the resulting foamed layer was 120 μm.

[0090] Next, the resin composition for the anchor coat layer, prepared according to the above-described formulation 3, is applied to the surface of the foamed layer formed on the release paper using a comma coater at a rate of 65 g / m². 2 The material was applied in a sheet-like form and then dried in a dryer at 100°C for 3 minutes, followed by 130°C for 3 minutes to form an anchor coat layer. The thickness of the resulting anchor coat layer was 22 μm.

[0091] Next, the adhesive layer resin composition prepared according to the above-described formulation 4 is applied to the surface of the anchor coat layer formed on the release paper using a knife coater at a rate of 360 g / m². 2 The material was applied in a sheet-like form and pre-dried in a dryer at 80°C for 2 minutes, followed by 100°C for 2 minutes, and then 130°C for 2 minutes. Next, the polyester circular knit fabric, a fibrous base material, was placed on top of the adhesive layer and laminated in a laminator at 120°C and 39.2 N / cm². 2 After applying pressure for 1 minute, the release paper was peeled off. The thickness of the resulting adhesive layer was 170 μm.

[0092] Next, the protective layer resin composition prepared according to the above-described formulation 5 is applied to the surface of the epidermal layer after the release paper has been removed, using a reverse coater at a rate of 59 g / m². 2 The material was applied in a sheet form. It was then dried in a dryer at 100°C for 3 minutes, followed by 140°C for 3 minutes to form a protective layer with a thickness of 11 μm, thereby obtaining synthetic leather.

[0093] Here, the thickness of each layer is obtained by observing the vertical cross-section of the synthetic leather with a microscope (Keyence Corporation, Digital HF Microscope VH-8000), measuring the thickness at 10 arbitrary points, and calculating the average value of these measurements.

[0094] [Example 2] Synthetic leather was obtained in the same manner as in Example 1, except that the foam layer and anchor coat layer were not formed and the thickness of the surface layer was set to 30 μm.

[0095] [Example 3] In Example 2, after forming the epidermal layer, the second resin composition for the epidermal layer, prepared according to Formulation 6 below, was applied to the surface of the epidermal layer formed on the release paper using a comma coater at a rate of 70 g / m². 2 The material was applied in a sheet form. It was then dried in a dryer at 100°C for 3 minutes, followed by 130°C for 3 minutes to form a second surface layer with a thickness of 30 μm. All other steps were carried out in the same manner as in Example 2 to obtain synthetic leather.

[0096] <Formulation 6: Second Epidermal Layer Resin Composition> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (DIC Corporation, Hydran WLI-620AR, water-based single-component type, solid content 40% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM XL-50, solids content 50% by mass) • Leveling agent: Silicone-based leveling agent: 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM Fluid H, solids content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by LANXESS, EUDERM Black B-N, solids content 25% by mass) Preparation method: The above-mentioned agents were mixed and stirred to prepare a second resin composition for the epidermal layer. The viscosity of the obtained second resin composition for the epidermal layer was 5,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C).

[0097] [Example 4] Synthetic leather was obtained in the same manner as in Example 1, except that the resin composition for the epidermal layer that forms the epidermal layer was changed to Formulation 7 below.

[0098] <Formulation 7: Resin composition for the epidermal layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin ME-8210NS, solvent-based one-component type, solid content 30% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 24 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The above-mentioned agents were mixed and stirred to prepare a resin composition for the epidermal layer. The viscosity of the obtained resin composition for the epidermal layer was 3,000 mPa·s (B-type viscometer, rotor: No. 4, 12 rpm, 23°C).

[0099] [Example 5] Synthetic leather was obtained in the same manner as in Example 1, except that a foam layer, an anchor coat layer, and a protective layer were not formed.

[0100] [Example 6] Synthetic leather was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer was set to 100 μm.

[0101] [Example 7] Synthetic leather was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer was set to 200 μm.

[0102] [Example 8] Synthetic leather was obtained in the same manner as in Example 1, except that the thickness of the foam layer was set to 70 μm.

[0103] [Example 9] Synthetic leather was obtained in the same manner as in Example 1, except that the thickness of the foam layer was set to 170 μm.

[0104] [Example 10] Synthetic leather was obtained in the same manner as in Example 1, except that the resin composition for the epidermal layer that forms the epidermal layer was changed to Formulation 8 below.

[0105] <Formulation 8: Resin composition for the epidermal layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin ME-8210NS, solvent-based one-component type, solid content 30% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent (HDI type): 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 30 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The viscosity was adjusted using a DMF (Direct Mold Filter) to 3,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C).

[0106] [Example 11] Synthetic leather was obtained in the same manner as in Example 1, except that the resin composition for the adhesive layer that forms the adhesive layer was changed to Formulation 9 below.

[0107] <Formulation 9: Resin composition for adhesive layer> (1) Production example 3: Polyisocyanate solution • Polyol component: Polycarbonate-based polyol: 20 parts by mass (Manufactured by Ube Industries, Ltd., ETERNACOLL UH-200, solid content 100% by mass) • Diisocyanate component: MDI system: 12 parts by mass (Manufactured by Tosoh Corporation, Millionate MT, 100% solids by mass) Preparation method: The above ingredients were mixed and heated to 25-80°C at a rate of 1°C / min. The mixture was stirred at 80°C for 60 minutes to complete the urethane reaction and obtain a polyisocyanate solution. (2) 32 parts by mass of the polyisocyanate solution from Production Example 3 and 152 parts by mass of the polyol solution from Production Example 2 were weighed and mixed by stirring to obtain a resin composition for adhesive layers containing a two-component curable, yellowing-type polycarbonate-based polyurethane resin.

[0108] [Example 12] Synthetic leather was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer was set to 20 μm.

[0109] [Comparative Example 1] Synthetic leather was obtained in the same manner as in Example 1, except that an anchor coat layer was not formed, and the resin composition for the foam layer and the resin composition for the adhesive layer were changed to formulations 10 and 11 below.

[0110] <Formulation 10: Resin composition for foamed layer> • Main component: Yellowing-type polycarbonate-based polyurethane resin: 100 parts by mass (LANXESS Corporation, LCC Binder UB-1770, water-based single-component type, solids content 30% by mass) • Hollow particles: Pre-foamed microcapsules: 25 parts by mass (Manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd., Matsumoto Microsphere FN-100S (pre-foamed by heat treatment), average particle size 50 μm, solid content 100% by mass, powder, outer shell: acrylonitrile polymer, inner contents: isopentane, pre-foamed product) • Crosslinking agent: Isocyanate-based crosslinking agent: 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM XL-50, solids content 50% by mass) • Leveling agent: Silicone-based leveling agent: 1 part by mass (Manufactured by LANXESS Corporation, AQUADERM Fluid H, solids content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by LANXESS Corporation, EUDERM Black BN, solids content 25% by mass) ·Water: 10 parts by mass Preparation method: The viscosity was adjusted to 5,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C).

[0111] <Formulation 11: Resin composition for adhesive layer> (1) Production example 4: Polyisocyanate solution • Polyol component: Polyether-based polyol: 20 parts by mass (Manufactured by AGC Inc., EXCENOL 2020, solids content 100% by mass) • Diisocyanate component: MDI system: 12 parts by mass (Manufactured by Tosoh Corporation, Millionate MT, solid content 100% by mass) Preparation method: The above ingredients were mixed and heated to 25-80°C at a rate of 1°C / min. The mixture was stirred at 80°C for 60 minutes to complete the urethane reaction and obtain a polyisocyanate solution. (2) Manufacturing example 5: Polyol solution • Main component: Polyether-based polyol: 30 parts by mass (Manufactured by AGC Inc., EXCENOL 1020, solid content 100 parts by mass) • Catalyst: Amine-based catalyst: 2 parts by mass (Manufactured by Tosoh Corporation, TEDA-L33, solid content 100% by mass) • Coloring agent: Carbon black pigment: 10 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) Flame retardant: Phosphorus-based flame retardant: 20 parts by mass (Manufactured by Clariant Japan Co., Ltd., PEKOFLAM STC powder, solid content 100% by mass) ·DMF: 90 parts by mass Preparation method: The viscosity was adjusted using a DMF (Direct Mold Filter) to 10,000 mPa·s (Type B viscometer, rotor: No. 4, 12 rpm, 23°C). (3) 32 parts by mass of the polyisocyanate solution from Production Example 4 and 152 parts by mass of the polyol solution from Production Example 5 were weighed and mixed by stirring to obtain a resin composition for adhesive layers containing a two-component curable, yellowing-type polyether-based polyurethane resin.

[0112] [Comparative Example 2] Synthetic leather was obtained in the same manner as in Example 1, except that the foam layer and anchor coat layer were not formed, and the resin composition for the surface layer that forms the surface layer was changed to the following formulation 12.

[0113] <Formulation 12: Resin composition for the epidermal layer> • Main component: Non-yellowing polyether-based polyurethane resin: 100 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Heimuren Y-201B, solvent-based one-component type, solids content 30% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent: 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 30 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The above-mentioned agents were mixed and stirred to prepare a resin composition for the epidermal layer. The viscosity of the obtained resin composition for the epidermal layer was 3,000 mPa·s (B-type viscometer, rotor: No. 4, 12 rpm, 23°C).

[0114] [Comparative Example 3] Synthetic leather was obtained in the same manner as in Example 1, except that the foam layer and anchor coat layer were not formed, and the resin composition for the surface layer that forms the surface layer was changed to the following formulation 13.

[0115] <Formulation 13: Resin composition for the epidermal layer> • Main component: Non-yellowing polycarbonate polyurethane resin: 100 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE-8850, solvent-based one-component type, solid content 30% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent: 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 30 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The above-mentioned agents were mixed and stirred to prepare a resin composition for the epidermal layer. The viscosity of the obtained resin composition for the epidermal layer was 3,000 mPa·s (B-type viscometer, rotor: No. 4, 12 rpm, 23°C).

[0116] [Comparative Example 4] Synthetic leather was obtained in the same manner as in Example 1, except that the foam layer and anchor coat layer were not formed, and the resin composition for the surface layer that forms the surface layer was changed to the following formulation 14.

[0117] <Formulation 14: Resin composition for the epidermal layer> • Main component: Silicone-modified, non-yellowing polycarbonate-based polyurethane resin: 135 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NES-9015-22, solvent-based one-component type, solids content 22% by mass) • Crosslinking agent: Isocyanate-based crosslinking agent: 5 parts by mass (Manufactured by Dainichi Seika Kogyo Co., Ltd., Rezamin NE crosslinking agent, solid content 75% by mass) • Coloring agent: Carbon black pigment: 30 parts by mass (Manufactured by Stahl Japan Co., Ltd., EX-GP-16-249 BLACK, solid content 45% by mass) ·DMF: 45 parts by mass Preparation method: The above-mentioned agents were mixed and stirred to prepare a resin composition for the epidermal layer. The viscosity of the obtained resin composition for the epidermal layer was 3,000 mPa·s (B-type viscometer, rotor: No. 4, 12 rpm, 23°C).

[0118] Regarding the synthetic leather obtained in the above examples and comparative examples, the surface color (L * a * b * L in color systems * The following measurements were taken, along with an evaluation of resistance to oleic acid and yellowing. The results are shown in Tables 1-3.

[0119] [Table 1]

[0120] [Table 2]

[0121] [Table 3]

[0122] As shown in Table 3, Comparative Example 1 used a yellowing-type polyether-based polyurethane resin for the adhesive layer, resulting in poor resistance to oleic acid. Comparative Example 2 used a polyether-based polyurethane resin for the surface layer, Comparative Example 3 used a non-yellowing-type polyurethane resin for the surface layer, and Comparative Example 4 used a silicone-modified non-yellowing-type polyurethane resin for the surface layer; all of these exhibited even worse resistance to oleic acid compared to Comparative Example 1.

[0123] In contrast, as shown in Tables 1 and 2, Examples 1 to 12 exhibited excellent oleic acid resistance, and in particular, Examples 1, 3, 4, and 6 to 12 passed the oleic acid resistance appearance change test even under heat treatment conditions of 100°C for 30 hours, and their abrasion resistance was also grade 4, demonstrating excellent oleic acid resistance. Furthermore, in Examples 1 to 3 and 5 to 12, the surface color L * The ratio was 27 or less, and despite not using a non-yellowing polyurethane resin, it exhibited excellent yellowing resistance.

[0124] The following are some embodiments, but are not limited to them. [1] Synthetic leather comprising a fibrous base material, an adhesive layer containing a non-yellowing polycarbonate polyurethane resin and / or a yellowing polycarbonate polyurethane resin, and a surface layer containing a non-yellowing polycarbonate polyurethane resin laminated on the fibrous base material via the adhesive layer. [2] The synthetic leather according to [1], further comprising a protective layer laminated on the surface layer. [3] The synthetic leather according to [2], wherein the protective layer comprises a polycarbonate-based polyurethane resin. [4] The synthetic leather according to [2] or [3], wherein the protective layer contains a matting agent, and the content of the matting agent in the protective layer is 3 to 40% by mass. [5] The synthetic leather according to any one of [1] to [4], further comprising a foamed layer containing a polycarbonate-based polyurethane resin between the surface layer and the adhesive layer. [6] The synthetic leather according to [5], wherein the foamed layer comprises a polycarbonate-based polyurethane resin that is resistant to yellowing. [7] The synthetic leather according to [5] or [6], wherein the thickness of the adhesive layer is greater than the thickness of the foam layer. [8] The synthetic leather according to any one of [5] to [7], further comprising an anchor coat layer containing a polycarbonate polyurethane resin between the foam layer and the adhesive layer. [9] The synthetic leather according to [8], wherein the anchor coat layer comprises a polycarbonate-based polyurethane resin that is resistant to yellowing.

[10] The synthetic leather according to [8] or [9], wherein the thickness of the adhesive layer is greater than the thickness of the anchor coat layer.

[11] Synthetic leather according to any one of [1] to

[10] , wherein the thickness of the adhesive layer is greater than the thickness of the surface layer.

[12] The synthetic leather according to any one of [1] to

[11] , wherein the non-yellowing polycarbonate polyurethane resin contained in the adhesive layer and / or the surface layer is obtained by (A1) a reaction between a polycarbonate polyol component and a non-yellowing polyisocyanate component, or (A2) a reaction between a polycarbonate polyol and a yellowing polyisocyanate component and contains an ultraviolet absorber and / or a light stabilizer.

[13] The synthetic leather according to

[12] , wherein the non-yellowing polyisocyanate component is an aromatic aliphatic polyisocyanate, preferably XDI and / or TMXDI.

[14] The synthetic leather according to any one of [1] to

[13] , wherein the yellowing polycarbonate-based polyurethane resin contained in the adhesive layer is obtained by the reaction of (B) a polycarbonate polyol component and a yellowing polyisocyanate component and does not contain an ultraviolet absorber and / or a light stabilizer.

[15] The synthetic leather according to any one of

[12] to

[14] , wherein the yellowing polyisocyanate component is an aromatic polyisocyanate, preferably at least one selected from the group consisting of phenylenediisocyanate, TDI, MDI, and naphthalene diisocyanate.

[16] The synthetic leather according to any one of [1] to

[15] , wherein 60% by mass or more, more preferably 80% by mass or more of the resin forming the surface layer is the non-yellowing polycarbonate-based polyurethane resin.

[17] The synthetic leather according to any one of [1] to

[16] , wherein the epidermal layer has a cross-linked structure formed by an isocyanate-based cross-linking agent, and the content of the isocyanate-based cross-linking agent in the epidermal layer is 0.1 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 3 to 10% by mass.

[18] The synthetic leather according to any one of [1] to

[17] , wherein the epidermal layer contains a coloring agent, and the content of the coloring agent in the epidermal layer is 20 to 38% by mass, more preferably 25 to 35% by mass, and even more preferably 28 to 32% by mass.

[19] The synthetic leather according to any one of [1] to

[18] , wherein 60% by mass or more, more preferably 80% by mass or more of the resin forming the adhesive layer is the non-yellowing polycarbonate-based polyurethane resin and / or the yellowing polycarbonate-based polyurethane resin.

[20] L * a * b * L in color systems * Synthetic leather as described in any one of items [1] to

[19] , having a surface color of 27 or less. [Explanation of Symbols]

[0125] 1, 10, 100… Synthetic leather, 2… Fiber-based base material, 3… Adhesive layer, 4… Epidermal layer, 5… Anchor coat layer, 6… Foam layer, 7… Protective layer

Claims

1. A fibrous base material, An adhesive layer having a thickness of 100 to 200 μm, comprising a non-yellowing polycarbonate-based polyurethane resin and / or a yellowing polycarbonate-based polyurethane resin, A surface layer having a thickness of 17 to 80 μm is laminated onto the fibrous substrate via the adhesive layer, comprising a non-yellowing polycarbonate-based polyurethane resin, A foamed layer having a thickness of 70 to 170 μm is provided between the surface layer and the adhesive layer, comprising a non-yellowing polycarbonate polyurethane resin. A protective layer with a thickness of 6 to 16 μm is laminated on the aforementioned surface layer, Synthetic leather with [specific properties].

2. The synthetic leather according to claim 1, wherein the thickness of the adhesive layer is greater than the thickness of the foam layer.

3. The synthetic leather according to claim 1 or 2, further comprising an anchor coat layer containing a polycarbonate-based polyurethane resin between the foam layer and the adhesive layer.

4. The synthetic leather according to claim 3, wherein the anchor coat layer contains a polycarbonate-based polyurethane resin that is resistant to yellowing.

5. The synthetic leather according to claim 3 or 4, wherein the thickness of the anchor coat layer is 17 to 27 μm.

6. The non-yellowing polycarbonate-based polyurethane resin is obtained by (A1) a reaction between a polycarbonate polyol component and a non-yellowing polyisocyanate component, or (A2) a reaction between a polycarbonate polyol and a yellowing polyisocyanate component and containing an ultraviolet absorber and / or a light stabilizer. The synthetic leather according to any one of claims 1 to 5, wherein the yellowing polycarbonate-based polyurethane resin is obtained by the reaction of (B) a polycarbonate polyol component and a yellowing polyisocyanate component and does not contain an ultraviolet absorber and / or a light stabilizer.

7. L ＊ a ＊ b ＊ L in color systems ＊ A synthetic leather according to any one of claims 1 to 6, having a surface color of 27 or less.

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