JP2020105665A - Napped artificial leather - Google Patents

Abstract

To provide a napped artificial leather which is imparted with a high level of flame retardancy using a non-halogen flame retardant without impairing a sense of luxury on the surface.SOLUTION: There is provided a napped artificial leather with a napped surface having a thickness of 0.25 to 1.5 mm, in which the napped artificial leather includes phosphorus-based flame retardant particles adhered to a polyurethane unevenly distributed in a range of 200 μm or less from a back surface. The napped artificial leather comprises a first polyurethane comprising: a polymer polyol which contains 60 mass% or more of a polycarbonate polyol and has 6.5 or less of a repeating average carbon number excluding a reactive functional group; and an organic polyisocyanate which contains at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate. The phosphorus-based flame retardant particles have an average particle diameter of 0.1 to 30 μm, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point or a decomposition temperature of 150°C or more, and a phosphorus-based flame retardant particle content ratio of 1 to 6 mass% in terms of phosphorus atom.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a napped artificial leather having both a high level of flame retardancy and an excellent high-grade surface feeling.

BACKGROUND ART Up to now, a napped artificial leather having an appearance like suede leather, which is obtained by raising one surface of an artificial leather raw machine in which a fiber entangled body such as a non-woven fabric of ultrafine fibers is impregnated with polyurethane, is known. The napped artificial leather is used as a material for shoes, clothing, gloves, bags, balls and the like, and as an interior material for buildings and vehicles. The napped artificial leather is superior in quality stability, heat resistance, water resistance, and abrasion resistance to natural leather such as suede leather, and has advantages such as easy maintenance.

By the way, in recent years, an interior material using a leather-like sheet such as artificial leather has been adopted as an interior material for public transport such as aircrafts, ships and railway vehicles and an interior material for public buildings such as hotels and department stores. Interior materials used in public places are required to have a high level of flame retardancy such as self-extinguishing property, low smoke generation property and low heat generation property in order to ensure safety in case of fire. In order to satisfy such a requirement for flame retardancy, it has been widely practiced to mix a halogen-based flame retardant having high flame retardancy with an interior material. However, since halogen-based flame retardants generate toxic halogen gas when they burn, non-use of halogen-based flame retardants is recommended by environmental officials and users. For example, the following Patent Documents 1 to 3 disclose a technique of using a phosphorus-based flame retardant or a metal hydroxide-based flame retardant to make a leather-like sheet flame-retardant.

JP-A-56-050985 JP, 2009-235628, A JP, 2013-227685, A

The napped artificial leather obtained by impregnating the voids inside the fiber entangled body of ultrafine fibers having a fineness of less than 1 dtex with polyurethane is a napped artificial fabric based on a knitted fabric of fibers having about 1 to 5 dtex, which is also called regular fiber. Compared to leather, the surface touch is smoother and superior in quality. However, the napped artificial leather containing ultrafine fibers has a lower flame retardancy than the napped artificial leather containing regular fibers because the surface area of the fibers is larger. Further, it is difficult to impart a high level of flame retardancy to a napped artificial leather containing ultrafine fibers without using a halogen-based flame retardant. Examples of the non-halogen flame retardant include phosphorus flame retardants. Specific examples include polyphosphoric acid metal salts, polyphosphoric acid inorganic salts such as polyphosphoric acid carbamate and polyphosphoric acid inorganic salts such as guanidine phosphate. The phosphorus-based flame retardant of However, since these polyphosphate inorganic salts and phosphates have relatively high water solubility, the flame retardant swells or dissolves due to moisture, water, or heat in the use environment, and the drying treatment after applying the flame retardant. And bleed in. When the flame retardant swells, dissolves, or bleeds, the flame retardant may whiten or color the napped surface, which is the main surface, thereby impairing the high-quality surface of the napped artificial leather. In addition, aromatic phosphoric acid esters and aliphatic phosphoric acid esters such as aliphatic phosphonic acid esters and aliphatic cyclic phosphonic acid esters have relatively low water solubility, but their flame retardant effect is insufficient. There was, the texture of the napped artificial leather was impaired, and bleeding was likely to occur.

The present invention provides a napped artificial leather containing a fiber entangled body of ultrafine fibers, which imparts a high level of flame retardancy by using a non-halogen flame retardant without impairing the high-grade feeling of the surface. To aim.

One aspect of the present invention includes a fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, and polyurethane impregnated into the fiber entangled body, and having a main surface that is a napped surface in which the ultrafine fibers are napped. A napped artificial leather having a length of 0.25 to 1.5 mm, further including phosphorus-based flame retardant particles adhered to polyurethane, which is unevenly distributed in a range of a thickness of 200 μm or less from the back surface with respect to the main surface. A polymer polyol is a reaction product of an organic polyisocyanate and a chain extender, and 60% by mass or more of the polymer polyol is a polycarbonate polyol, and the repeating average carbon number excluding reactive functional groups is 6.5 or less. The isocyanate contains the first polyurethane containing at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and the phosphorus-based flame retardant particles have an average particle diameter of 0. 5 to 30 μm, phosphorus atom content is 14% by mass or more, solubility in water at 30° C. is 0.2% by mass or less, melting point or decomposition temperature is 150° C. or more in the absence of melting point, and phosphorus-based flame retardant The napped artificial leather has a particle content of 1 to 6 mass% in terms of phosphorus atom content. According to such a configuration, in a napped artificial leather containing a fiber entangled body of ultrafine fibers, a napped artificial leather provided with a high level of flame retardancy by using a non-halogen flame retardant without impairing the high-grade feeling of the surface. Obtainable.

Further, it is preferable that 90 to 100% by mass of the phosphorus-based flame retardant particles be present in a range of a thickness of 200 μm or less from the viewpoint of not impairing the high-class surface feeling.

Further, when the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the polyurethane is 5 to 20 mass% in terms of phosphorus atom, it is possible to sufficiently suppress the decrease in flame retardancy due to the polyurethane. It is preferable from the point.

In addition, the polyurethane includes a first polyurethane existing in the entire thickness section and a second polyurethane unevenly distributed in a thickness range of 200 μm or less, and the phosphorus-based flame retardant particles are attached to the second polyurethane. However, it is preferable because the phosphorus-based flame retardant particles are likely to be unevenly distributed in a thickness range of 200 μm or less.

Further, the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is 10 to 30% by mass in terms of phosphorus atom, and thus the second polyurethane reduces the flame retardancy. Is preferable because the influence of is small.

As the phosphorus-based flame retardant particles described above, organic phosphinic acid metal salts, aromatic phosphonic acid esters, and phosphoric acid ester amides are particularly preferable.

According to the present invention, in a napped artificial leather containing a fiber entangled body of ultrafine fibers, a napped artificial leather provided with a high level of flame retardancy by using a non-halogen flame retardant can be obtained without impairing the high-grade feeling of the surface. ..

The napped artificial leather of the present embodiment includes a fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, and polyurethane impregnated into the fiber entangled body, and a main surface that is a napped surface in which the ultrafine fibers are napped. A napped artificial leather having a thickness of 0.25 to 1.5 mm, further comprising phosphorus-based flame retardant particles adhered to polyurethane, which is unevenly distributed in a range of a thickness of 200 μm or less from the back surface with respect to the main surface, and the polyurethane is a polymer. It is a reaction product of a polyol, an organic polyisocyanate and a chain extender, and the polymer polyol is 60% by mass or more of a polycarbonate polyol and has a repeating average carbon number of 6.5 or less excluding reactive functional groups, The organic polyisocyanate contains the first polyurethane containing at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and the phosphorus-based flame retardant particles have an average particle size of 0.1 to 30 μm, phosphorus atom content is 14% by mass or more, solubility in water at 30° C. is 0.2% by mass or less, and melting point or decomposition temperature is 150° C. or more when no melting point is present. The napped artificial leather in which the content ratio of the flame retardant particles is 1 to 6 mass% in terms of phosphorus atom conversion content ratio.

The napped artificial leather of the present embodiment includes, for example, a first polyurethane impregnated into a fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, and has a main surface that is a napped surface on which napped ultrafine fibers are napped. A resin liquid containing phosphorus-based flame retardant particles and a second polyurethane is unevenly distributed on the back surface of the napped artificial leather having a thickness of 0.25 to 1.5 mm with respect to the main surface of the raw machine in a range of a thickness of 200 μm or less from the back surface. It is obtained by subjecting to flame-retardant treatment.

Examples of the fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less include fiber structures such as nonwoven fabrics, woven fabrics and knitted fabrics containing ultrafine fibers having a fineness of 0.5 dtex or less. Among these, a non-woven fabric of ultrafine fibers is particularly preferable because it provides a napped artificial leather excellent in suppleness and fullness because of its high homogeneity. In the present embodiment, as a fiber entangled body of ultrafine fibers, a nonwoven fabric of ultrafine fibers will be described in detail as a representative example.

As a method for producing a nonwoven fabric of ultrafine fibers, for example, a web is produced by melt-spinning sea-island type composite fibers, the web is entangled, and then the sea component is selectively removed from the sea-island type composite fibers to obtain ultrafine fibers. And a method of forming. As a method for producing a web, a method of forming a long fiber web by collecting on a net without cutting sea-island type composite fibers of long fibers spun by a spunbond method, or cutting the long fibers into staples. And a method of forming a short fiber web. Of these, long-fiber webs are particularly preferable because they are excellent in compactness and fullness. Further, the formed web may be subjected to a fusion treatment in order to impart morphological stability. Examples of the entanglement treatment include a method of stacking about 5 to 100 webs, and needle punching or high-pressure water flow treatment. In addition, in any of the steps from removing the sea component of the sea-island type composite fiber to forming the ultrafine fiber, the sea-island type composite fiber is densified and enriched by performing a fiber shrinkage treatment such as heat shrinkage treatment with steam. The feeling can be improved.

In the present embodiment, the case of using the sea-island type composite fiber will be described in detail. However, even if an ultrafine fiber generating fiber other than the sea-island type composite fiber is used, the ultrafine fiber generating type fiber is not used, and the ultrafine fiber is directly used. May be spun into a nonwoven fabric. In addition, as a specific example of the ultrafine fiber-generating fiber other than the sea-island type composite fiber, a plurality of ultrafine fibers are lightly bonded and formed immediately after spinning, and a plurality of ultrafine fibers are formed by loosening by mechanical operation. Any fiber capable of forming an ultrafine fiber, such as a peelable split-type fiber or a petal-type fiber obtained by alternately collecting a plurality of resins in a petal-like shape in the melt spinning process, is not particularly limited. ..

The resin of the island component that forms the ultrafine fibers of the sea-island type composite fiber is not particularly limited. Specifically, for example, aromatic polyesters such as polyethylene terephthalate (PET), isophthalic acid modified PET, sulfoisophthalic acid modified PET, polybutylene terephthalate, polyhexamethylene terephthalate; polylactic acid, polyethylene succinate, polybutylene succinate, Aliphatic polyesters such as polybutylene succinate adipate and polyhydroxybutyrate-polyhydroxyvalerate resin; polyamides such as polyamide 6, polyamide 66, polyamide 10, polyamide 11, polyamide 12, polyamide 6-12; polypropylene, polyethylene, polybutene Polyolefin such as polymethylpentene and chlorine-based polyolefin. These may be used alone or in combination of two or more. Among these, PET or modified PET, polylactic acid, polyamide 6, polyamide 12, polyamide 6-12, polypropylene and the like are preferable.

Further, as the resin of the sea component forming the sea-island type composite fiber, a resin having a different solubility to a solvent or a decomposability to a decomposing agent than the resin of the island component is selected. Specific examples of the thermoplastic resin constituting the sea component include water-soluble polyvinyl alcohol, polyethylene, polypropylene, polystyrene, ethylene propylene resin, ethylene vinyl acetate resin, styrene ethylene resin, and styrene acrylic resin.

The sea component of the sea-island type composite fiber is dissolved or decomposed and removed at an appropriate stage after forming the web. The sea-island type composite fibers are made into ultrafine fibers by such decomposition removal or dissolution extraction removal, and ultrafine fibers in the form of fiber bundles are formed.

The fineness of the ultrafine fibers is 0.5 dtex or less. Further, it is preferably 0.001 to 0.4 dtex, and particularly preferably 0.01 to 0.3 dtex. When the fineness is more than 0.5 dtex, the napped surface tends to have a high-grade feeling. The fineness is determined by taking a cross section in the thickness direction of the napped artificial leather with a scanning microscope at a magnification of 2000 times to obtain the cross-sectional area of the single fiber, and from the cross-sectional area and the specific gravity of the resin forming the fiber, one single fiber is obtained. The fineness of can be calculated. The fineness can be defined as the average value of the average fineness of 100 single fibers, which is obtained from the photographed image.

The first polyurethane is evenly applied to the entire nonwoven fabric. The first polyurethane imparts morphological stability to a fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, or imparts a high-grade feeling to the napped surface by restraining the ultrafine fibers. Note that polyurethane tends to burn more easily than ultrafine fibers. In the napped artificial leather of the present embodiment, by adding the flame retardant to the back side, it is possible to suppress the influence of the addition of the flame retardant on the appearance of the main surface, which is the napped surface. On the other hand, by using a specific polyurethane as the polyurethane, it is possible to improve the flame retardancy of the main surface, which is the raised surface.

Polyurethane is a reaction product of a polymer polyol, an organic polyisocyanate and a chain extender, and the polymer polyol is 60% by mass or more of a polycarbonate polyol and has a repeating average carbon number of 6 excluding reactive functional groups. 5 or less, and the organic polyisocyanate includes a first polyurethane including at least one selected from the group consisting of 4,4′-dicyclohexylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate. Such a first polyurethane is excellent in self-extinguishing property, has a small amount of heat generation and smoke generation, and exhibits a high level of flame retardancy.

Examples of the polycarbonate polyol include polycarbonate polyols such as polyhexamethylene carbonate diol, poly(3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, polycyclohexane carbonate diol, and the like. These copolymers are mentioned.

Further, the polymer polyol may contain a polymer polyol other than the polycarbonate-based polyol within a range not exceeding 40% by mass. Examples of high-molecular polyols other than polycarbonate-based polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and poly(methyltetramethylene glycol) and copolymers thereof; polyethylene adipate diol, poly 1,2 -Propylene adipate diol, poly 1,3-propylene adipate diol, polybutylene adipate diol, polybutylene sebacate diol, polyhexamethylene adipate diol, poly(3-methyl-1,5-pentane adipate) diol, poly(3- Examples include polyester polyols such as methyl-1,5-pentane sebacate) diol and polycaprolactone diol, and copolymers thereof; polycarbonate polyols having 6.5 or more carbon atoms; polyester carbonate polyols and the like. Further, a polyfunctional alcohol such as a trifunctional alcohol or a tetrafunctional alcohol, or a short chain alcohol such as ethylene glycol may be used. These may be used alone or in combination of two or more.

The polymer polyol used for producing the first polyurethane has a polycarbonate average content of 60 mass% or more and a repeating average carbon number of 6.5 or less excluding reactive functional groups.

The mass ratio of the polycarbonate contained in the polymer polyol used for producing the first polyurethane is 60% by mass or more, and preferably 70% by mass or more. When the mass ratio of the polycarbonate contained in the polymer polyol is less than 60 mass %, the amount of heat generation and the amount of smoke generation are large.

Further, the repeating average carbon number excluding the reactive functional group of the polymer polyol used in the production of polyurethane is 6.5 or less, preferably 6.0 or less. Even when the repeating average carbon number excluding the reactive functional group of the polymer polyol exceeds 6.5, the heat generation amount and the smoke generation amount increase. Here, the average carbon number excluding the reactive functional group of the polymer polyol refers to a polymer polyol-forming reaction of a carbonate group (-OCOO-), an ester group (-COO-), an ether group (-O-), etc. Is defined as the number of carbon atoms of the number of hydrocarbons excluding the reactive functional group in. The average number of carbons excluding reactive functional groups when using two or more polymer polyols is the number of hydrocarbons excluding reactive functional groups such as two or more carbonate groups, ester groups and ether groups. The average value of the number of carbons of is used as the calculated value.

The molecular weight of the polymer polyol is not particularly limited, but is, for example, about 200 to 6000 in average molecular weight.

The organic polyisocyanate used for producing the first polyurethane contains at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate. Further, 60% by mass or more, further 70% by mass or more, particularly 80% by mass or more of the organic polyisocyanate is at least one selected from the group consisting of 4,4′-dicyclohexylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate. Is preferable because it has excellent self-extinguishing property, and the amount of heat generation and the amount of smoke generation are small.

As the organic polyisocyanate used for producing the first polyurethane, in addition to 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, other organic isocyanate may be used in combination. Specific examples of such organic isocyanates include non-yellowing type diisocyanates such as aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and norbornene diisocyanate; 2,4-tolylene diisocyanate, 2,6- Examples thereof include aromatic diisocyanates such as tolylene diisocyanate and xylylene diisocyanate polyurethane. Moreover, you may use together polyfunctional isocyanate, such as trifunctional isocyanate and tetrafunctional isocyanate, or blocked polyfunctional isocyanate as needed. These may be used alone or in combination of two or more.

Examples of the chain extender used for producing the first polyurethane include hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and its derivatives, adipic acid dihydrazide, isophthalic acid. Diamines such as dihydrazide; triamines such as diethylenetriamine; tetramines such as triethylenetetramine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis(β-hydroxyethoxy) ) Benzene, diols such as 1,4-cyclohexanediol; triols such as trimethylolpropane; pentaols such as pentaerythritol; amino alcohols such as aminoethyl alcohol and aminopropyl alcohol. These may be used alone or in combination of two or more. Among these, hydrazine, piperazine, ethylenediamine, hexamethylenediamine, isophoronediamine and derivatives thereof, triamines such as diethylenetriamine, ethylene glycol, propylene glycol, 1,4-butanediol and derivatives thereof are used in combination of two or more thereof. It is preferable that the mechanical properties are excellent. In addition, during chain elongation reaction, monoamines such as ethylamine, propylamine and butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; methanol, ethanol, propanol, butanol, etc. You may use monools together. Above all, it is preferable that the number of carbon atoms excluding the reactive functional group is 6 or less, because the self-extinguishing property is excellent and the amount of heat generation and the amount of smoke generation are small.

Further, in order to control the water absorption of polyurethane, the adhesiveness to fibers, and the hardness, a cross-linking agent containing two or more functional groups in the molecule capable of reacting with the functional groups of the monomer unit forming polyurethane, for example, A crosslinked structure may be formed by adding a self-crosslinking compound such as a carbodiimide compound, an epoxy compound, an oxazoline compound, or a polyisocyanate compound or a polyfunctional blocked isocyanate compound.

As a polyurethane emulsion, a forced emulsification type polyurethane emulsion prepared by adding an emulsifier without having an ionic group in the polyurethane skeleton or an ionic group such as a carboxyl group, a sulfonic acid group or an ammonium group in the polyurethane skeleton. Examples thereof include a self-emulsifying polyurethane emulsion which is emulsified by self-emulsification, and a polyurethane emulsion in which an emulsifier is used in combination with an ionic group of a polyurethane skeleton. For example, in order to introduce a carboxyl group into the polyurethane skeleton, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butanoic acid, 2,2-bis(hydroxymethyl)valeric acid, etc. Examples of the method include incorporating a unit such as the carboxyl group-containing diol of the above into the polyurethane skeleton.

The first polyurethane preferably has a 100% modulus of 0.5 to 7 MPa, more preferably 1 to 5 MPa from the viewpoint that a supple texture can be obtained and a smooth surface touch and surface physical properties can be imparted. If the 100% modulus is too low, it tends to soften when heat is applied and restrain the ultrafine fibers, resulting in a decrease in supple texture and smooth surface touch. If the 100% modulus is too high, smooth surface touch tends to be deteriorated and the texture tends to be hard.

The first polyurethane is, for example, a fiber entanglement of ultrafine fiber-generating fibers such as sea-island type composite fibers for forming ultrafine fibers, or a fiber entanglement of ultrafine fibers and a polyurethane emulsion such as polyurethane emulsion or polyurethane. After being impregnated with the solution, it is solidified to be applied to the fiber entangled body. Examples of the method of impregnating the fiber entangled body with the first polyurethane emulsion or solution include a method using a knife coater, a bar coater, or a roll coater, and a method of dipping. When an emulsion is used, a method of heat treatment in a drying device at 50 to 200° C., a method of heat treatment in a dryer after infrared heating, a method of heat treatment in a dryer after steam treatment, or ultrasonic wave Polyurethane can be solidified by a method of heat-treating with a dryer after heating, or a method of combining these.

As the polyurethane emulsion, it is also pliable to use a self-emulsifying polyurethane and a forced emulsifying polyurethane in combination, for example, a polyurethane emulsion containing 20 to 100% by mass of the self-emulsifying polyurethane and 0 to 80% by mass of the compulsory emulsifying polyurethane. It is preferable in that a texture can be obtained. Further, the dispersion average particle diameter of the polyurethane emulsion is preferably 0.01 to 1 μm, and more preferably 0.03 to 0.5 μm.

When the fiber entangled body is impregnated with the emulsion of polyurethane and then dried, the emulsion may migrate to the surface layer of the fiber entangled body, which may make it difficult to apply it uniformly in the thickness direction. In such a case, the dispersion particle size of the emulsion is adjusted, the type and amount of the ionic groups of the polyurethane are adjusted, and an ammonium salt whose pH changes depending on the temperature of about 40 to 100° C. is added to disperse the water. An associative heat-sensitive gelling agent such as a monovalent or divalent alkali metal salt or alkaline earth metal salt, a nonionic emulsifier, an associative water-soluble thickener, or a water-soluble silicone compound, which lowers stability, or The migration can be suppressed by adding a water-soluble polyurethane compound to lower the water dispersion stability.

The proportion of the first polyurethane contained in the napped artificial leather is 3 to 50% by mass, further 5 to 40% by mass, and particularly 7 to 35% by mass, which indicates high flame retardancy and high-grade surface appearance and morphology. It is preferable because it has an excellent balance with stability and surface properties.

The fiber entangled body containing the first polyurethane is subjected to a wet heat shrinkage treatment or a press treatment, if necessary, to adjust the apparent density, the basis weight and the thickness, and finish into a raw fabric of artificial leather. Then, the raw fabric of the artificial leather is sliced if necessary. Then, by buffing at least one surface of the artificial leather raw material with a contact buff, an emery buff or the like, a raised artificial leather raw material having a raised surface is manufactured. The buffing is preferably performed using, for example, sandpaper or emery paper having a count of 120 to 600. In this way, a raw fabric of napped artificial leather having a napped surface in which fibers on the buffed surface are napped and napped with ultrafine fibers is manufactured. If necessary, the napped artificial leather machine can be dyed, kneaded and softened, blanked and softened, reverse-seal brushing, antifouling, hydrophilic, lubricant, softener, and antioxidant. Finishing treatment such as agent treatment, ultraviolet absorber treatment, and fluorescent agent treatment may be performed.

The thickness of the raised nap artificial leather is approximately equal to the thickness of the finally obtained nap artificial leather. The thickness of the raised nap artificial leather is specifically 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, and more preferably 0.4 to 1.0 mm. When the thickness of the raised nap artificial leather exceeds 1.5 mm, it becomes difficult to obtain a sufficient flame retardant effect.

The napped artificial leather of the present embodiment contains the phosphorus-based flame retardant particles and the second polyurethane on the back surface of the nap artificial surface having a thickness of 0.25 to 1.5 mm described above, which is the main surface of the greige. It can be obtained by subjecting the resin liquid to a flame retarding treatment which is a treatment for unevenly distributing the resin liquid in a range of 200 μm or less from the back surface. Here, in the napped artificial leather of the present embodiment, the phosphorus-based flame retardant particles are unevenly distributed in the range of a thickness of 200 μm or less from the back surface with respect to the main surface, most of the phosphorus-based flame retardant particles present in the napped artificial leather, specifically Specifically, it means that 90 to 100% by mass, and further 95 to 100% by mass of the phosphorus-based flame retardant particles are present in a range of a thickness of 200 μm or less from the back surface with respect to the main surface. The thickness of the phosphorus-based flame retardant particles from the back surface with respect to the unevenly distributed main surface is preferably 50 to 200 μm, more preferably 70 to 180 μm, and particularly preferably 100 to 150 μm. The thickness of the region in which the phosphorus-based flame retardant particles are unevenly distributed in the napped artificial leather is confirmed by observing a cross section in a direction parallel to the thickness direction of the napped artificial leather with a scanning electron microscope.

In this way, the phosphorus content of the phosphorus flame retardant particles in the range of 200 μm or less from the back surface of the main surface of the napped artificial leather to the napped surface is 1 to 6% by mass in terms of phosphorus atom conversion content. By unevenly distributing the particles of the flame-retardant agent, it is possible to impart a high level of flame-retardancy by using the non-halogen flame-retardant agent without impairing the high-grade feeling of the surface.

The content of the phosphorus-based flame retardant particles unevenly distributed in the range of 200 μm or less from the back surface to the napped surface of the main surface in the napped artificial leather is 1 to 6 mass% in terms of phosphorus atom, and preferably 1.5. Is about 5.5 mass %. When the phosphorus atom-based content of the phosphorus flame retardant particles in the napped artificial leather is less than 1% by mass, a high level of flame retardancy cannot be obtained. Further, when the content ratio of phosphorus-based flame retardant particles in the napped artificial leather in terms of phosphorus atom exceeds 6% by mass, the phosphorus-based flame retardant particles are fixed from the back surface to a thickness of 200 μm or less without falling off. It becomes difficult to disperse the napped artificial leather, and the suppleness of the napped artificial leather is lost, and the high-grade feeling of the surface is deteriorated.

Moreover, the phosphorus-based flame retardant particles contained in the napped artificial leather of the present embodiment have an average particle diameter of 0.5 to 30 μm, a phosphorus atom content of 14% by mass or more, and a solubility in water at 30° C. of 0.2% by mass. Hereinafter, it is a flame-retardant compound containing a phosphorus atom which is a particulate solid at room temperature and has a decomposition temperature of 150° C. or higher when a melting point or no melting point is present.

The average particle diameter of the phosphorus-based flame retardant particles is 0.1 to 30 μm, preferably 0.5 to 10 μm, and more preferably 1 to 5 μm. When the average particle diameter exceeds 30 μm, the content of the phosphorus-based flame retardant particles is sufficiently within the range of 200 μm or less from the back surface of the napped artificial leather so that the content of the phosphorus-based flame retardant particles is 1 to 6% by mass in terms of phosphorus atom conversion. It becomes difficult to infiltrate into, and the flame retardant effect tends to be insufficient. If the average particle size is less than 0.5 μm, the particles tend to aggregate and become unevenly dispersed, which tends to cause uneven flame retardancy.

The phosphorus atom content of the phosphorus-based flame retardant particles is 14% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more. When the phosphorus atom content of the phosphorus-based flame retardant particles is less than 14% by mass, it becomes difficult to impart a high level of flame retardancy.

Further, the phosphorus-based flame retardant particles have a solubility in water at 30° C. of 0.2% by mass or less, and preferably 0.15% by mass or less. When the phosphorus-based flame retardant particles having a solubility in water at 30° C. of more than 0.2% by mass are used, they tend to bleed to the napped surface when they absorb moisture or get wet with water during production or use.

Further, as the phosphorus-based flame retardant particles, the solubility in hot water at 90° C. of hot water is 5% by mass or less, and further 3% by mass or less, even when they come into contact with hot water during production or use, It is preferable in that it is difficult for the napped surface to bleed and the dimensional change due to moisture absorption is difficult.

Further, the phosphorus-based flame retardant particles are solid particles at room temperature which have a melting point or a decomposition temperature of 150° C. or more, preferably 200° C. or more when no melting point is present. When the melting point or the melting point does not exist and the decomposition temperature is lower than 150° C., the flame retardant is softened by drying after being treated, etc. to be solidified and not in the form of particles, and the ultrafine fibers are bundled, It is easy to damage the surface touch and texture. In addition, it becomes easy to melt and drop in the combustion process, and it becomes difficult to impart a high level of flame retardancy. Here, the melting point of the phosphorus-based flame retardant particles is specified by the melting peak temperature of thermogravimetric differential thermal analysis (TG-DTA) or differential scanning calorimeter analysis (DSC). Further, the thermal decomposition temperature when there is no melting point is specified by the decomposition start temperature by thermogravimetric differential thermal analysis (TG-DTA). The measurement conditions are not particularly limited, but the measurement is performed at a temperature rising rate of 5 to 10° C./min in a nitrogen atmosphere.

The phosphorus-based flame retardant particles as described above are selected from organic phosphinic acid metal salts such as metal salts of dialkylphosphinic acid and metal salts of monoalkylphosphinic acid; aromatic phosphonic acid esters; phosphoric acid ester amides and the like. These may be used alone or in combination of two or more. Among these, a metal salt of dialkylphosphinic acid or a metal salt of monoalkylphosphinic acid is preferable because it has high water resistance and heat resistance, a high phosphorus atom content, and a high flame retardant effect.

The second polyurethane used for fixing the phosphorus-based flame retardant particles contained in the napped artificial leather of the present embodiment may be the same as or different from the first polyurethane described above. The second polyurethane preferably has a 100% modulus of 0.5 to 5 MPa, more preferably 1 to 4 MPa, since a supple texture can be obtained and the flame retardant can be prevented from falling off.

On the back surface of the nap artificial surface of the nap artificial leather having a thickness of 0.25 to 1.5 mm with respect to the nap surface, the resin liquid containing phosphorus flame retardant particles and the second polyurethane is 200 μm or less from the back surface. There is no particular limitation on the method of the flame retarding treatment that is applied so as to be unevenly distributed in the range. Specifically, a treatment liquid containing phosphorus-based flame retardant particles and a second polyurethane, for example, by gravure coating, direct coating, roll coating, or spray coating on the back surface of the main surface of the napped artificial leather with respect to the napped surface. Examples of the method include applying and drying while adjusting the application amount and viscosity.

The viscosity of the treatment liquid containing the phosphorus-based flame retardant particles and the second polyurethane is 200 to 10,000 mPa·sec, and further 500 to 5000 mPa·sec. It is easy to allow the napped artificial leather to properly sink from the back side of the greige machine to be unevenly distributed within a thickness of 200 μm or less, thereby imparting high flame retardancy without impairing the high-grade feeling of the napped surface which is the main surface. It is preferable because it can

As the resin liquid containing the second polyurethane, for example, a polyurethane emulsion containing phosphorus-based flame retardant particles prepared by dispersing phosphorus-based flame retardant particles in a polyurethane emulsion which is an emulsion of the second polyurethane is preferably used. To be In the case of a polyurethane emulsion, the average particle size of the emulsion is preferably 10 μm or less, and more preferably 5 μm. The drying temperature of the resin liquid is not particularly limited, but it is usually preferably 100 to 160°C.

The content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is 10 to 30% by mass, further 12 to 30% by mass, and particularly 15 to 25% by mass in terms of phosphorus atom. % Is preferable. When the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is the above-mentioned ratio, it is preferable because the effect of reducing the flame retardancy due to the combustion of the second polyurethane is small.

The content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is in the range of 10 to 30 mass% in terms of phosphorus atom, and The mass is preferably 60 to 90% by mass, and more preferably 70 to 85% by mass.

Further, the proportion of the second polyurethane contained in the napped artificial leather is not particularly limited, but it is 2 to 15% by mass, and further 4 to 10% by mass that the second polyurethane reduces the flame retardancy. It is preferable because the phosphorus-based flame retardant particles can be sufficiently fixed while making the value smaller.

When the ultrafine fibers form a fiber bundle derived from the sea-island type composite fiber, the polyurethane may be impregnated inside the fiber bundle or attached to the outside of the fiber bundle. When the sea-island type composite fiber is subjected to the ultrafine fiber treatment, the thermoplastic resin of the sea component is removed from the sea-island type composite fiber to form voids inside the ultrafine fiber bundle. Therefore, the second polyurethane, which is applied after the sea-island type composite fiber is subjected to the ultrafine fiber treatment, easily binds the ultrafine fibers that form the fiber bundle by impregnating the inside of the fiber bundle. Therefore, the second polyurethane impregnated in the ultrafine fiber bundle contributes to restrain the ultrafine fiber bundle and improve the shape retention of the fiber entangled body.

The proportion of the total amount of polyurethane including the first polyurethane and the second polyurethane contained in the napped artificial leather is not particularly limited, but is 2 to 40% by mass, and further 5 to 35% by mass. It is preferable because the effect of lowering the flame retardancy due to the combustion of can be reduced.

Further, the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the polyurethane including the first polyurethane and the second polyurethane is preferably 5 to 20 mass% in terms of phosphorus atom, Further, it is preferably 6 to 20% by mass from the viewpoint of excellent balance between flame retardancy and suppleness of the napped artificial leather.

The total basis weight of the polyurethane containing the first polyurethane and the second polyurethane contained in the napped artificial leather is 10 to 150 g/m ² , further 10 to 100 g/m ² , and particularly 10 to 50 g/m ² . It is preferable that the napped artificial leather having a particularly good balance between self-extinguishing property and high-grade surface feeling can be obtained.

The napped artificial leather may be softened for the purpose of smoothing the surface touch while improving the smoothness of the surface. Examples of the softening include a method in which napped artificial leather is brought into close contact with an elastic sheet, mechanically contracted in the vertical direction (MD in the production line), and heat-treated by heat treatment in the contracted state.

The napped artificial leather of the present embodiment thus obtained has a basis weight of 150 to 600 g/m ² , and further 170 to 400 g/m ² , which sufficiently maintains high flame retardancy, Phosphorus flame retardant particles are preferable because they do not easily affect the appearance and touch of the napped surface and further reduce the high-grade feeling of the surface.

The napped artificial leather has a thickness of 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, and more preferably 0.4 to 1.0 mm. When the thickness of the napped artificial leather is less than 0.25 mm, the flame retardant is likely to be exposed on the surface and the surface quality and touch are deteriorated. When the thickness of the napped artificial leather exceeds 1.5 mm, the flame retardancy is lowered.

The apparent density of the napped artificial leather is not particularly limited, but it is 0.25 to 0.75 g/cm ³ , and more preferably 0.35 to 0.65 g/cm ³ because the surface has a high fiber density, It is preferable from the viewpoint that the nap feeling and surface touch are good.

The napped artificial leather of the present embodiment is preferably used, for example, as a wall covering material in which a napped artificial leather and an interior base material (back board) are bonded together with an adhesive for composites. Specific examples of the interior base material include concrete, brick, tile, ceramic tile, fiber reinforced cement plate, glass fiber mixed cement plate, calcium silicate plate, steel, aluminum, metal plate, glass, mortar, plaster, Examples include stone, gypsum board, rock wool, glass wool board, wood wool cement board, hard wood wool cement board, wood wool cement board, pulp cement board, and flame-retardant plywood. Among them, concrete, brick, roof tile, ceramic tile, fiber reinforced cement board, glass fiber mixed cement board, calcium silicate board, steel, aluminum, in order to suppress combustibility when combined with napped artificial leather, Metal plates and glass are preferred.

Examples of adhesives for composites include starch-based, (alkyl)cellulose-based, vinyl acetate-based, ethylene vinyl acetate-based, acrylic resin-based, polyurethane-based, chloroprene-based, phenol-based, nitrile-based, ester-based, silicone Examples thereof include adhesives containing a mixture of a system, a fluorine system, a copolymer or a mixture thereof, or a metal compound such as a metal salt or a hydroxide. Among these, starch-based, (alkyl)cellulose-based, vinyl acetate-based, chloroprene-based, phenol-based, nitrile-based, fluorine-based, silicone-based, and these, from the viewpoint of suppressing combustibility when combined with napped artificial leather Examples thereof include copolymers and mixtures, and adhesives mixed with metal salts and hydroxides.

The flame retardancy of a composite material in which an interior base material is adhered to the back surface of a napped artificial leather with an adhesive can be evaluated using an ISO5660-1 cone calorimeter. The flame retardancy evaluated by a combustion test using a cone calorimeter includes the total heat generation value by combustion (THR; MJ/m ² ), the maximum heat generation value by combustion per unit area and unit time (PHRR; kW/ m ² ), the maximum average rate of heat dissipation (MARHE; kW/m ² ).

Composite material on the back surface of the napped artificial leather of the present embodiment formed by bonding the interior base material with an adhesive, the total calorific value (THR) is 10 MJ / m ² or less, further realizing the 8 MJ / m ² or less of the composite material It is possible. Further, the composite material of the present embodiment can realize a composite material having a maximum heat generation amount (PHRR) of 250 kW/m ² or less, and further 200 kW/m ² or less. Further, the composite material of the present embodiment can realize a composite material having a maximum average heat dissipation rate (MARHE; kW/m ² ) of 90 kW/m ² or less.

Further, the napped artificial leather of the present embodiment has a high level of flame retardancy, a high-class surface feeling, a supple texture, and a sense of fulfillment, and therefore, for example, a public transportation machine such as an aircraft, a ship, a railroad, a vehicle, or It is preferably used for applications requiring a high level of flame retardancy such as self-extinguishing property, low heat generation property, low smoke generation property, such as seats of public buildings such as hotels and department stores, materials for sofas, interiors such as walls, and the like.

Hereinafter, the present invention will be described more specifically with reference to Examples. The scope of the present invention is not limited to the examples.

[Example 1]
Water-soluble thermoplastic polyvinyl alcohol (PVA) was used as the sea component resin, and isophthalic acid-modified polyethylene terephthalate was used as the island component resin to prevent the sea-island type composite fiber from melting. Specifically, the molten resin of the sea component resin and the island component resin is respectively supplied to the spinneret for composite spinning in which nozzle holes for forming 25 island component resin distributions in the sea component resin are arranged. The molten fiber of the sea-island type composite fiber was discharged from the nozzle hole. At this time, the pressure was adjusted so that the mass ratio of the sea component and the island component was 25/75, ie, sea component/island component.

Then, the sea-island composite fiber having a fineness of 3.3 dtex was spun by drawing the molten fiber of the sea-island composite fiber with a suction device and stretching. The spun sea-island type composite fiber was continuously deposited on a movable net, and was lightly pressed by a heated metal roll to suppress surface fluffing. Then, after separating the sea-island type composite fiber from the net, the web was passed between a metal roll and a back roll and hot-pressed to obtain a web having a basis weight of 31 g/m ² .

Next, using a cross wrapper device, eight layers of web were piled up so that the total basis weight was 300 g/m ² , and needle punching was alternately performed from both sides of the web for entanglement treatment. The basis weight of the entangled web, which was the web after needle punching, was 440 g/m ² .

The entangled web was subjected to wet heat shrinkage for 30 seconds under the conditions of 70° C. and 50% RH humidity. The area shrinkage ratio before and after the wet heat shrinkage treatment was 47%.

Then, the contracted entangled web was impregnated with an emulsion of the first polyurethane containing ammonium sulfate as a gelling agent, and then dried. The first polyurethane is a polymer polyol that is 100% polycarbonate polyol and has a repeating average carbon number of 6 excluding reactive functional groups, an organic polyisocyanate that is 4,4′-dicyclohexylmethane diisocyanate, and chain extension. It was a reaction product with the agent and was a self-emulsifying type amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa.

Then, the entangled web provided with the first polyurethane is immersed in hot water to dissolve and remove the PVA to obtain a non-woven fabric in which a fiber bundle containing 25 ultrafine fibers with a fineness of 0.1 dtex is three-dimensionally entangled. A raw machine of artificial leather containing was produced. The content of the first polyurethane in the artificial leather greige was 12% by mass.

Then, the raw fabric of the artificial leather was sliced and divided into two in the thickness direction, and the anti-slicing surface was buffed to finish the raw fabric of the napped artificial leather having a suede-like napped face. The napped artificial leather had a thickness of 0.5 mm, a basis weight of 250 g/m ² , and an apparent density of 0.50 g/cm ³ .

Then, the fabric of the napped artificial leather was dyed using a circular dyeing machine, dried, and then impregnated with a softening agent and further dried.

Then, using a gravure coater equipped with a 35-mesh gravure roll on the sliced surface of the dyed napped artificial leather raw machine, particles of a metal salt of dialkylphosphinic acid, which is a phosphorus-based flame retardant, were dispersed at 2000 mPa·sec. The second polyurethane emulsion was applied at 110 g/m ² and dried at 120° C. to remove water. The particles of the metal salt of dialkylphosphinic acid have a dispersed particle diameter (median diameter: D ₅₀ ) of 4 μm measured by a laser diffraction/scattering particle diameter distribution measuring device and a phosphorus atom content rate of 23.5% by mass. The solubility in water at 30°C was less than 0.2% by mass, and the melting point and decomposition temperature were more than 250°C.

The second polyurethane emulsion contained 10% by mass of the second polyurethane and 28% by mass of the metal salt of dialkylphosphinic acid. The second polyurethane is a polymer polyol that is 100% polycarbonate polyol and has a repeating average carbon number of 5.5 excluding reactive functional groups, and an organic polyisocyanate that is 4,4′-dicyclohexylmethane diisocyanate. It was a reaction product with a chain extender and was a forced emulsification type amorphous polycarbonate urethane having a 100% modulus of 1.0 MPa.

Then, the flame-retardant napped artificial leather raw material is shrunk at a drum temperature of 120° C. and a conveying speed of 10 m/min to shrink 5.0% in the vertical direction (length direction), and then the surface is sealed. By carrying out, napped artificial leather having a suede-like napped surface was obtained. The napped artificial leather had a thickness of 0.52 mm, a basis weight of 290 g/m ² , and an apparent density of 0.56 g/cm ³ .

The napped artificial leather contained 10% by mass of the first polyurethane, 5% by mass of the second polyurethane, and 15% by mass of particles of the metal salt of dialkylphosphinic acid. As a result, the napped artificial leather contained 2.6 mass% of metal salt of dialkylphosphinic acid in terms of phosphorus atom content. Further, the phosphorus atom-equivalent mass% to the total amount of the particles of the metal salt of dialkylphosphinic acid, the first polyurethane and the second polyurethane was 10.3 mass %. Further, the phosphorus atom-equivalent mass% based on the total amount of the second polyurethane and the particles of the metal salt of dialkylphosphinic acid was 17.3 mass %.

Then, the obtained napped artificial leather was evaluated according to the following evaluation methods.

(Surface appearance)
The napped surface of the napped artificial leather was touched and judged according to the following criteria.
A: The surface touch was smooth, and there was no rough feel due to the phosphorus-based flame retardant particles.
B: The surface touch was rough, and the quality was inferior.
C: The texture was hard and inferior in luxury.
D: Phosphorus flame retardant particles bleed during storage and the surface is whitened.

(Thickness, basis weight, apparent density)
According to JIS L1913, the apparent density (g/cm ³ ) is calculated by measuring the thickness (mm) and the basis weight (g/cm ² ) of the napped artificial leather and dividing the basis weight by the thickness for conversion. did.

(Measurement of thickness of region where phosphorus-based flame retardant particles attached to polyurethane are unevenly distributed)
The cross section direction of the napped artificial leather was cut out, and 10 points were uniformly selected from the whole cross section, and the thickness of the region where the phosphorus-based flame retardant particles were present was measured from the back surface at 10 points with a scanning electron microscope at a magnification of 100 times. Then, the average value of 8 points excluding the maximum value and the minimum value of the thickness was taken as the unevenly distributed thickness of the phosphorus-based flame retardant particles.

(Average particle size of phosphorus flame retardant particles)
Cut out the cross section direction of the napped artificial leather, select 10 points evenly from the entire cross section, select the area where the phosphorus flame retardant particles are present from the back side with a scanning electron microscope at a magnification of 1000 times, and select the diameter of 10 particles. Measured. Then, the average value of the eight particle diameters excluding the maximum value and the minimum value was taken as the average particle diameter of the phosphorus-based flame retardant particles.

(Vertical method combustion test: self-extinguishing)
The vertical method flame resistance of the napped artificial leather was measured by the FAR25 Appendix F Part1(a)(1)(ii) US aircraft interior material combustion test standard. Specifically, the napped artificial leather was cut into 50.8 mm×304.8 mm to prepare a test piece. Then, the test piece was vertically fixed to the sample holder of the combustion test apparatus. A burner was placed directly below one end of the test piece, and after indirect flame for 12 seconds, the burning distance, self-extinguishing time, and drop self-extinguishing time of the test piece were measured. The average of n=10 was calculated.

(Horizontal method combustion test)
The suede-like artificial leather was subjected to the horizontal combustion test according to the FMVSS 302 combustion test standard. Specifically, a suede-like artificial leather was cut into a size of 102 mm mm×356 mm, and a test piece having a marked line of 38 mm from one end of the sample was prepared. Then, the test piece was horizontally fixed to the sample holder of the combustion test apparatus. A burner was placed at the sample end on the marked line side of the test piece, and after indirect flame for 15 seconds, the burning distance and burning time of the test piece were measured. The average of n=10 was calculated. Self-extinguishing (SE) before self-extinguishing before the marked line, self-extinguishing when burning distance 50 mm or less and burning time 60 seconds or less over the marked line, slow burning property when burning velocity 100 mm/min or less, burning velocity 100 mm/min or more was set as flammability.

The above evaluation results are shown in Table 1 below.

[Example 2]
In Example 1, instead of the second polyurethane emulsion containing 10% by weight of the second polyurethane and 28% by weight of the metal salt of dialkylphosphinic acid, 22% by weight of the second polyurethane and 28% by weight of the dialkylphosphine were used. A napped artificial leather was obtained and evaluated in the same manner except that the second polyurethane emulsion containing an acid metal salt was used. The results are shown in Table 1.

[Example 3]
In the same manner as in Example 1, except that the artificial leather having the first polyurethane content of 24% by mass was used instead of the artificial leather having the first polyurethane content of 12% by mass. A napped artificial leather was obtained and evaluated. The results are shown in Table 1.

[Example 4]
In Example 1, the second polyurethane emulsion in which the particles of the metal salt of dialkylphosphinic acid, which is a phosphorus-based flame retardant, were dispersed was coated at a rate of 60 g/m ² instead of 110 g/m ^2. Other than the above, the napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 5]
In Example 1, instead of the non-woven fabric in which fiber bundles containing 25 0.1 dtex ultrafine fibers are three-dimensionally entangled, a non-woven fabric in which fiber bundles containing 6 0.4 dtex ultrafine fibers are three-dimensionally entangled did. Further, as the first polyurethane, a mass ratio of amorphous polycarbonate (average carbon number 5.5 excluding reactive functional groups) and polyether polyol (average carbon number 4 excluding reactive functional groups) 60/40 Which is a reaction product of a polymer polyol having a repeating average carbon number of 4.9 excluding reactive functional groups, an organic polyisocyanate that is 4,4′-diphenylmethane diisocyanate, and a chain extender, A self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa was used. Further, as the phosphorus-based flame retardant particles, the monoalkylphosphinic acid metal salt shown in Table 1 was used instead of the dialkylphosphinic acid metal salt. Otherwise, in the same manner as in Example 1, a napped artificial leather was obtained and evaluated. The results are shown in Table 1.

[Example 6]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1, except that the aromatic phosphonate ester shown in Table 1 was used as the phosphorus-based flame retardant particle instead of the metal salt of dialkylphosphinic acid. The results are shown in Table 1.

[Example 7]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1 except that the phosphoric acid ester amides shown in Table 1 were used instead of the metal salt of dialkylphosphinic acid as the phosphorus-based flame retardant particles. The results are shown in Table 1.

[Example 8]
The sea-island type composite fiber was melt-prevented by using polyethylene as the sea component resin and isophthalic acid-modified polyethylene terephthalate as the island component resin. Specifically, the molten resin of the sea component resin and the island component resin is respectively supplied to the spinneret for composite spinning in which nozzle holes for forming 25 island component resin distributions in the sea component resin are arranged. The molten fiber of the sea-island type composite fiber was discharged from the nozzle hole. At this time, the pressure was adjusted so that the mass ratio of the sea component and the island component was 25/75, ie, sea component/island component.

Then, the sea-island type composite fiber was spun by sucking the molten fiber of the sea-island type composite fiber with a suction device and stretching. The spun sea-island type composite fiber was continuously deposited on a movable net, and was lightly pressed by a heated metal roll to suppress surface fluffing. Then, after separating the sea-island type composite fiber from the net, it was passed between a metal roll and a back roll and hot pressed to obtain a web.

Next, using a cross wrapper device, eight layers of web were piled up so that the total basis weight was 320 g/m ² , and needle punching was alternately performed from both sides of the web for entanglement treatment. Then, the entangled web was subjected to wet heat shrinkage for 30 seconds under the conditions of 70° C. and 50% RH humidity.

Then, the contracted entangled web is impregnated with the N,N-dimethylformamide solution of the first polyurethane, and then immersed in a mixed solution of N,N-dimethylformamide and water to be solidified, followed by polyethylene with toluene. Was extracted and dried. The first polyurethane had a mass ratio of 75/25 of polycarbonate polyol (average carbon number 6 excluding reactive functional groups) and polyester polyol (average carbon number 4 excluding reactive functional groups), Which is a reaction product of a polymer polyol having a repeating average carbon number of 4.9 excluding a volatile functional group, an organic polyisocyanate that is 4,4′-diphenylmethane diisocyanate, and a chain extender, and having a 100% modulus of 5 It was an amorphous polycarbonate urethane having a pressure of 0.0 MPa.

Otherwise, in the same manner as in Example 1, a napped artificial leather was obtained and evaluated. The results are shown in Table 1.

[Example 9]
Polyethylene was used as the sea component resin and 6-nylon was used as the island component resin to prevent the sea-island type composite fiber from melting. Specifically, polyethylene and 6-nylon were mixed at a mass ratio of 50/50 and melted, and the molten resin was supplied to the spinneret for mixing and spun out from the nozzle hole. The number of islands was about 600 on average, and the fibers were drawn to obtain 5.5 dtex fibers. This fiber was crimped, cut into 51 mm and carded to obtain a short fiber web having a basis weight of 100 g/m ² . A six-layer superposed web was prepared using a cross-lapper device, sprayed with an oil solution, needle-punched under the conditions of 1500 punch/cm ² , and then hot-pressed to give an apparent density of 0. A fiber entangled body having a thickness of 40 g/cm ³ and a thickness of 1.5 mm was obtained.
Then, the fiber entangled body is impregnated with the N,N-dimethylformamide solution of the first polyurethane, and then immersed in a mixed solution of N,N-dimethylformamide and water for coagulation, followed by extraction of polyethylene with toluene. Dried. The first polyurethane had a mass ratio of 75/25 of polycarbonate polyol (average carbon number 6 excluding reactive functional groups) and polyester polyol (average carbon number 4 excluding reactive functional groups), and Which is a reaction product of a polymer polyol having a repeating average carbon number of 4.9 excluding a functional group, 4,4'-diphenylmethane diisocyanate and a chain extender, and having a 100% modulus of 5 The polyurethane was 0.0 MPa. Other than that, the napped artificial leather was obtained and evaluated in the same manner as in Example 1 except that the dye was changed from disperse dyeing to gold-containing dyeing. The results are shown in Table 1.

[Example 10]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1, except that the artificial leather having a thickness of 1.3 mm was used. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, instead of the second polyurethane emulsion containing 10% by weight of the second polyurethane and 28% by weight of metal salt of dialkylphosphinic acid, 10% by weight of the second polyurethane and 6.8% by weight. A napped artificial leather was obtained and evaluated in the same manner except that the second polyurethane emulsion containing the metal salt of dialkylphosphinic acid was used. The viscosity of the aqueous dispersion of phosphorus-based flame retardant particles and the second polyurethane was 100 mPa·sec. The results are shown in Table 2.

[Comparative Example 2]
In Example 1, instead of the second polyurethane emulsion containing 10% by weight of the second polyurethane and 28% by weight of the metal salt of dialkylphosphinic acid, an aqueous dispersion containing 28% by weight of ammonium polyphosphate was used. The napped artificial leather was obtained and evaluated in the same manner except that it was used. The results are shown in Table 2.

[Comparative Example 3]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1 except that ammonium polyphosphate shown in Table 1 was used as the phosphorus-based flame retardant particles instead of the metal salt of dialkylphosphinic acid. The results are shown in Table 2.

[Comparative Example 4]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1 except that the aromatic phosphoric acid ester shown in Table 1 was used as the phosphorus-based flame retardant particles instead of the metal salt of dialkylphosphinic acid. The results are shown in Table 2. Note that the phosphorus-based flame retardant was treated in the form of an aqueous dispersion during the treatment with the flame retardant, but when observed in a napped artificial leather, it was not resin-formed into a particulate form.

[Comparative Example 5]
A napped artificial leather was obtained and evaluated in the same manner as in Example 4 except that the first polymer elastic body was changed to polyether polyurethane (repeating average carbon number 5 excluding reactive functional groups). The results are shown in Table 2.

[Comparative Example 6]
In Example 4, the number of island components of the spinneret was changed from 25 to 4, and ultrafine fibers having an average fineness of 0.6 dtex were used, and the first polymer elastic body was made of polycarbonate-based polyurethane (reactive functional group). A napped artificial leather was obtained and evaluated in the same manner except that the average carbon number was repeated except for the group. The results are shown in Table 2.

Referring to Tables 1 and 2, all of the napped artificial leathers obtained in Examples 1 to 10 have a good surface quality, have a supple texture, and further have good self-extinguishing property and smoke generation. The napped artificial leather has a high level of flame retardancy and a small amount and a small amount of heat generated by combustion. On the other hand, the napped artificial leather obtained in Comparative Example 1, in which the phosphorus-based flame retardant particles are few and the flame-retardant particles are present inside, the phosphorus-based flame retardant is exposed on the surface and is inferior in the high-class surface feeling, and the flame retardancy is high. Was not enough. Further, the napped artificial leather obtained in Comparative Example 2 in which ammonium polyphosphate was used as the phosphorus-based flame retardant particles was inferior in high-grade feeling due to bleeding with time. In addition, the napped artificial leather obtained in Comparative Example 3 was slightly inferior in flame retardancy, bleeding occurred over time, and was inferior in high-grade surface feeling. Further, in Comparative Example 4 in which the phosphorus-based flame retardant particles were changed to the aromatic phosphate ester, the texture was hard and the flame retardancy was insufficient. Further, in Comparative Example 5 in which the napped artificial leather had a large fineness and a high fabric weight, the flame retardancy was insufficient.

Claims (6)

A fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, and polyurethane impregnated into the fiber entangled body, having a main surface that is a napped surface on which the ultrafine fibers are napped 1.5mm napped artificial leather,
Further comprising phosphorus-based flame retardant particles attached to the polyurethane, which are unevenly distributed in a range of a thickness of 200 μm or less from the back surface with respect to the main surface,
The polyurethane is a reaction product of a polymer polyol, an organic polyisocyanate and a chain extender, and the polymer polyol is 60% by mass or more of a polycarbonate polyol and has a repeating average carbon number excluding a reactive functional group. 6.5 or less, the organic polyisocyanate comprises a first polyurethane, containing at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate,
When the phosphorus-based flame retardant particles have an average particle size of 0.1 to 30 μm, a phosphorus atom content of 14% by mass or more, a solubility in water at 30° C. of 0.2% by mass or less, and a melting point or no melting point. The decomposition temperature is above 150°C,
The napped artificial leather, wherein the content of the phosphorus-based flame retardant particles is 1 to 6 mass% in terms of phosphorus atom conversion content. The napped artificial leather according to claim 1, wherein 90 to 100 mass% of the phosphorus-based flame retardant particles are present in the range of the thickness of 200 µm or less. The napped artificial leather according to claim 1 or 2, wherein the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the polyurethane is 5 to 20% by mass in terms of phosphorus atom. The polyurethane includes the first polyurethane existing in the entire thickness section and the second polyurethane unevenly distributed in the range of the thickness of 200 μm or less,
The napped artificial leather according to any one of claims 1 to 3, wherein the phosphorus-based flame retardant particles are attached to the second polyurethane. The napped artificial leather according to claim 4, wherein the content ratio of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is 10 to 30% by mass in terms of phosphorus atoms. The said phosphorus flame retardant particle contains at least 1 sort(s) of compound selected from the group which consists of organic phosphinic acid metal salt, aromatic phosphonic acid ester, and phosphoric acid ester amide, The any one of Claims 1-5. Napped artificial leather.