JP7265354B2 - Raised artificial leather and composite material using it - Google Patents

Description

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

Conventionally, there has been known a napped artificial leather having a suede leather-like appearance, which is obtained by raising one surface of an artificial leather greige obtained by impregnating polyurethane into a fiber entanglement such as a nonwoven fabric of ultrafine fibers. Raised artificial leather is used as materials for shoes, clothing, gloves, bags, balls, etc., and as interior materials for buildings and vehicles. Compared with natural leather such as suede leather, napped artificial leather is superior in quality stability, heat resistance, water resistance, and abrasion resistance, and has advantages such as easy maintenance.

By the way, in recent years, interior materials using leather-like sheets such as artificial leather have been adopted as interior materials for public transportation such as aircraft, ships and railway vehicles, and as interior materials 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, low smoke and low heat generation in order to ensure safety in the event of a fire. In order to meet such requirements for flame retardancy, it has been widely practiced to blend a halogen-based flame retardant with high flame retardancy into interior materials. However, since halogen-based flame retardants generate toxic halogen gas when burned, non-use of halogen-based flame retardants is recommended by environmental public organizations and users. For example, Patent Literatures 1 to 3 below disclose techniques using phosphorus-based flame retardants and metal hydroxide-based flame retardants to impart flame retardancy to leather-like sheets.

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

Raised artificial leather obtained by impregnating the voids inside the fiber entanglement of ultrafine fibers with a fineness of less than 1 dtex with polyurethane is a napped artificial leather based on a knitted or woven fabric of fibers of about 1 to 5 dtex, which is also called regular fiber. Compared to leather, the surface touch is smooth and has an excellent sense of quality. However, the napped artificial leather containing ultrafine fibers has lower flame retardancy than the napped artificial leather containing regular fibers because the surface area of the fibers is larger. In addition, it has been difficult to impart a high level of flame retardancy to napped artificial leather containing ultrafine fibers without using a halogen-based flame retardant. Examples of non-halogen flame retardants include phosphorus flame retardants. Specific examples include metal polyphosphates, ammonium polyphosphates, inorganic polyphosphates such as carbamate polyphosphates, and phosphates such as guanidine phosphate. of phosphorus-based flame retardants. However, these polyphosphate inorganic salts and phosphates have a relatively high water solubility, so the flame retardant may swell or dissolve due to humidity, water, or heat in the usage environment, and the drying treatment after applying the flame retardant may occur. It bleeds in When the flame retardant swells, dissolves, or bleeds, the flame retardant whitens or colors the napped surface, which is the main surface, and sometimes impairs the surface quality of the napped artificial leather. In addition, aliphatic phosphate esters such as aromatic-containing phosphate esters, aliphatic phosphonate esters, and aliphatic cyclic phosphonate esters have relatively low water solubility, but their flame-retardant effect is insufficient. In addition, the texture of the napped artificial leather is damaged, and bleeding is likely to occur.

An object of the present invention is to provide a napped artificial leather containing a fiber entanglement of ultrafine fibers, which is imparted with a high level of flame retardancy by using a non-halogen flame retardant without impairing the surface luxury feeling. 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 and phosphorus-based flame retardant particles impregnated into the fiber entangled body, and the raised ultrafine fibers are raised. A napped artificial leather with a thickness of 0.25 to 1.5 mm having a main surface that is a surface, wherein the polyurethane is a first polyurethane that exists throughout the thickness cross section and a thickness of 200 μm or less from the back surface to the main surface. 90 to 100% by mass of the phosphorus-based flame retardant particles are attached to the second polyurethane, and the first polyurethane is a polymer polyol and an organic polyisocyanate is a reaction product between and a chain extender, and 60% by mass or more of the polymer polyol is polycarbonate polyol, and the repeating average number of carbon atoms excluding reactive functional groups is 6.5 or less, and the organic polyisocyanate is Polyurethane containing at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, phosphorus-based flame retardant particles having an average particle diameter of 0.1 to 30 μm and phosphorus atoms The content is 14% by mass or more, the solubility in water at 30 ° C. is 0.2% by mass or less, the melting point or the decomposition temperature when there is no melting point is 150 ° C. or more, and the phosphorus-based flame retardant in the napped artificial leather The napped artificial leather has a particle content of 1 to 6% by mass in terms of phosphorus atoms. According to such a configuration, in the napped artificial leather containing the fiber entanglement of ultrafine fibers, the napped artificial leather is imparted with a high level of flame retardancy using a non-halogen flame retardant without impairing the surface luxury feeling. Obtainable.

When 90 to 100% by mass of the phosphorus -based flame retardant particles are present in the thickness range of 200 μm or less, the high-quality feel of the surface is not impaired .

Further, the content of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles, the first polyurethane, and the second polyurethane is 5 to 20% by mass in terms of phosphorus atoms. It is preferable from the point of being able to sufficiently suppress the decrease in flammability.

In addition, the polyurethane includes a first polyurethane that exists throughout the thickness cross section and a second polyurethane that is unevenly distributed in a thickness range of 200 μm or less, and phosphorus-based flame retardant particles are attached to the second polyurethane. Thereby, the phosphorus-based flame retardant particles can be unevenly distributed within a thickness range of 200 μm or less.

Further, the content 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. is preferable because the influence of is small.

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

According to the present invention, it is possible to obtain a napped artificial leather containing a fiber entangled body of ultrafine fibers, which is imparted with a high level of flame retardancy using a non-halogen flame retardant without impairing the surface's luxurious appearance. .

The napped artificial leather of the present embodiment includes a fiber entanglement containing ultrafine fibers having a fineness of 0.5 dtex or less and polyurethane impregnated into the fiber entanglement, and has a main surface that is a napped surface on which the ultrafine fibers are raised. A napped artificial leather with a thickness of 0.25 to 1.5 mm, further comprising phosphorus-based flame retardant particles attached to polyurethane unevenly distributed in a range of 200 μm or less in thickness from the back surface 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 60% by mass or more of the polymer polyol is polycarbonate polyol, and the repeating average carbon number excluding reactive functional groups is 6.5 or less, The organic polyisocyanate contains a 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 0.1 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, a melting point or a decomposition temperature in the absence of a melting point of 150° C. or more, and a phosphorus-based The napped artificial leather contains flame retardant particles in a content ratio of 1 to 6% by mass in terms of phosphorus atoms.

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

Examples of fiber entangled bodies 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 0.5dtex or less. Among these, a nonwoven fabric made of ultrafine fibers is particularly preferable because it has a high homogeneity, so that a napped artificial leather having excellent suppleness and a feeling of fullness can be obtained. In this embodiment, a nonwoven fabric of ultrafine fibers will be described in detail as a representative example of the entangled body of ultrafine fibers.

As a method for producing a nonwoven fabric of ultrafine fibers, for example, islands-in-sea composite fibers are melt-spun to produce a web, and after the web is entangled, the sea component is selectively removed from the islands-in-the-sea composite fibers to produce ultrafine fibers. such as forming As a method of manufacturing a web, there is a method of forming a long fiber web by collecting sea-island composite fibers of long fibers spun by a spunbond method or the like on a net without cutting them, or a method of forming a long fiber web by cutting long fibers into staples. and forming a short fiber web. Among these, the long-fiber web is particularly preferred because it is excellent in denseness and fullness. Also, the formed web may be subjected to a fusion treatment to impart shape stability. As the entangling treatment, for example, about 5 to 100 webs are piled up, and a method of needle punching or high-pressure water jet treatment can be used. In any of the steps from removing the sea component of the sea-island composite fiber to forming the ultrafine fiber, the sea-island composite fiber is densified and solidified by applying a fiber shrinkage treatment such as a heat shrink treatment with steam. can improve the feeling.

In this embodiment, the case of using sea-island composite fibers will be described in detail. may be spun to produce a nonwoven fabric. As a specific example of the ultrafine fiber-generating fibers other than the islands-in-the-sea composite fiber, a plurality of ultrafine fibers are formed by lightly adhering to each other immediately after spinning, and are unraveled by a mechanical operation to form a plurality of ultrafine fibers. Any fiber that can form ultrafine fibers, such as a peel-split type fiber or a petal-shaped fiber in which a plurality of resins are alternately assembled in a petal shape in the melt spinning process, can be used without particular limitation. .

The island component resin forming the ultrafine fibers of the sea-island 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, and polyhexamethylene terephthalate; polylactic acid, polyethylene succinate, polybutylene succinate, Aliphatic polyesters such as polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate resin; polyamides such as polyamide 6, polyamide 66, polyamide 10, polyamide 11, polyamide 12, polyamide 6-12; polypropylene, polyethylene, polybutene , polymethylpentene, and polyolefins such as chlorinated polyolefins. 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 preferred.

As the sea component resin for forming the islands-in-sea composite fiber, a resin is selected which differs in solubility to a solvent or decomposability to a decomposing agent from that of the island component resin. Specific examples of thermoplastic resins constituting the sea component include water-soluble polyvinyl alcohol, polyethylene, polypropylene, polystyrene, ethylene-propylene resin, ethylene-vinyl acetate resin, styrene-ethylene resin, styrene-acrylic resin, and the like.

The sea component of the islands-in-sea composite fiber is removed by dissolving or decomposing at an appropriate stage after forming the web. By such decomposition removal or dissolution-extraction removal, the islands-in-the-sea composite fibers are made into ultrafine fibers to form fiber bundle-like ultrafine fibers.

The fineness of the ultrafine fibers is 0.5 dtex or less. It is more preferably 0.001 to 0.4 dtex, particularly preferably 0.01 to 0.3 dtex. If the fineness exceeds 0.5 dtex, the napped surface tends to lose its luxurious feel. In addition, the fineness is obtained by photographing the cross section of the napped artificial leather in the thickness direction with a scanning microscope at a magnification of 2000 times, obtaining 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 The fineness of can be calculated. The fineness can be defined as the average value of fineness of 100 average single fibers evenly obtained from photographed images.

The first polyurethane is evenly applied to the entire nonwoven fabric. The first polyurethane binds the ultrafine fibers, thereby imparting shape stability to the fiber entangled body containing the ultrafine fibers having a fineness of 0.5 dtex or less, and imparting a high-quality feel to the napped surface. Note that polyurethane tends to be more flammable than microfibers. In the napped artificial leather of the present embodiment, by applying a flame retardant to the back side, it is possible to suppress the influence of the flame retardant on the appearance of the main surface, which is the napped surface, due to the addition of the flame retardant. 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 napped surface.

Polyurethane is a reaction product of a polymer polyol, an organic polyisocyanate and a chain extender, and 60% by mass or more of the polymer polyol is polycarbonate polyol, and the average repeating carbon number excluding reactive functional groups is 6.5. 5 or less, and the organic polyisocyanate contains 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 properties, generates a small amount of heat and smoke, and exhibits a high level of flame retardancy.

Examples of polycarbonate polyols include polycarbonate polyols such as polyhexamethylene carbonate diol, poly(3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, and polycyclohexane carbonate diol, and and copolymers thereof.

In addition, as the high-molecular polyol, a high-molecular polyol other than the polycarbonate-based polyol may be included within a range not exceeding 40% by mass. Examples of polymer polyols other than polycarbonate-based polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 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- methyl-1,5-pentane sebacate) diol, polyester polyols such as polycaprolactone diol and copolymers thereof; polycarbonate polyols having 6.5 or more carbon atoms; and polyester carbonate polyols. Moreover, you may use polyfunctional alcohols, such as trifunctional alcohol and tetrafunctional alcohol, and short-chain alcohols, such as ethylene glycol. These may be used alone or in combination of two or more.

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

The mass ratio of the polycarbonate contained in the polymer polyol used to produce the first polyurethane is 60% by mass or more, preferably 70% by mass or more. When the mass ratio of the polycarbonate contained in the polymer polyol is less than 60% by mass, the amount of heat generated and the amount of smoke generated are increased.

In addition, the repeating average number of carbon atoms excluding the reactive functional groups of the polymer polyol used for producing the polyurethane is 6.5 or less, preferably 6.0 or less. When the repeating average number of carbon atoms excluding the reactive functional groups of the polymer polyol exceeds 6.5, the amount of heat generated and the amount of smoke generated also increase. Here, the average carbon number excluding the reactive functional groups of the polymer polyol means the polymer polyolization reaction of carbonate groups (-OCOO-), ester groups (-COO-), ether groups (-O-), etc. is defined as the carbon number of the hydrocarbon number excluding the reactive functional groups in. In addition, the average number of carbon atoms excluding reactive functional groups when two or more types of polymer polyols are used is the number of hydrocarbons excluding two or more types of reactive functional groups such as carbonate groups, ester groups, and ether groups. A value obtained by calculating the average value of the number of carbon atoms.

Although the molecular weight of the high-molecular polyol is not particularly limited, it is, for example, about 200 to 6,000 in average molecular weight.

Also, 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. At least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate accounts for 60% by mass or more, further 70% by mass or more, particularly 80% by mass or more of the organic polyisocyanate. It is preferable from the viewpoint of excellent self-extinguishing property and reduction in the amount of heat generated and the amount of smoke generated.

In addition to 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, other organic isocyanates may be used in combination as the organic polyisocyanate used to produce the first polyurethane. Specific examples of such organic isocyanates include non-yellowing diisocyanates such as aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and norbornene diisocyanate; Aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate polyurethane, and the like are included. Moreover, you may use together polyfunctional isocyanate, such as trifunctional isocyanate and tetrafunctional isocyanate, and blocked polyfunctional isocyanate as needed. These may be used alone or in combination of two or more.

Examples of chain extenders used in the production of the first polyurethane include hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and its derivatives, adipic acid dihydrazide, and 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 ) diols such as benzene and 1,4-cyclohexanediol; triols such as trimethylolpropane; pentaols such as pentaerythritol; and aminoalcohols 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 its derivatives, triamines such as diethylenetriamine, ethylene glycol, propylene glycol, 1,4-butanediol and its derivatives are used in combination of two or more. is preferable from the viewpoint of excellent mechanical properties. In addition, during the chain elongation reaction, together with a chain elongation agent, monoamines such as ethylamine, propylamine, butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; methanol, ethanol, propanol, butanol, etc. Monools may be used in combination. Among them, 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 generated and smoke generated is small.

In addition, in order to control the water absorption rate of polyurethane, adhesion to fibers, and hardness, cross-linking agents containing two or more functional groups in the molecule capable of reacting with functional groups possessed by monomer units forming polyurethane, such as , a carbodiimide compound, an epoxy compound, an oxazoline compound, or a self-crosslinking compound such as a polyisocyanate compound or a polyfunctional block isocyanate compound may be added to form a crosslinked structure.

Polyurethane emulsions include forced emulsification type polyurethane emulsions that have no ionic groups in the polyurethane skeleton and are emulsified by adding an emulsifier, and ionic groups such as carboxyl groups, sulfonic acid groups, and ammonium groups in the polyurethane skeleton. and a self-emulsifying polyurethane emulsion formed by self-emulsification, and a polyurethane emulsion using both an emulsifier and an ionic group in the polyurethane skeleton. For example, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butanoic acid, 2,2-bis(hydroxymethyl)valeric acid and the like are used to introduce carboxyl groups into the polyurethane skeleton. and a method of incorporating a unit such as a carboxyl group-containing diol in 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 of obtaining a supple texture and imparting a smooth surface touch and surface physical properties. If the 100% modulus is too low, the fabric tends to soften when subjected to heat to bind the ultrafine fibers, thereby deteriorating the supple texture and smooth surface touch. On the other hand, if the 100% modulus is too high, the smooth touch of the surface tends to deteriorate and the texture tends to become hard.

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

As the polyurethane emulsion, a combination of self-emulsifying polyurethane and forcibly emulsified polyurethane can be used. It is preferable from the point that a texture can be obtained. The dispersion average particle size of the polyurethane emulsion is preferably 0.01 to 1 μm, more preferably 0.03 to 0.5 μm.

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

The ratio of the first polyurethane contained in the napped artificial leather is 3 to 50% by mass, further 5 to 40% by mass, particularly 7 to 35% by mass. It is preferable from the point of being excellent in balance with stability and surface physical properties.

The fiber entangled body containing the first polyurethane is, if necessary, subjected to wet heat shrinkage treatment or press treatment to adjust the apparent density, basis weight and thickness, and finished into a greige artificial leather. The artificial leather greige is then sliced as needed. Then, at least one surface of the artificial leather greige is buffed with a contact buff, an emery buff, or the like to produce a napped artificial leather greige having a napped surface. Buffing is preferably performed using, for example, sandpaper or emery paper of about 120 to 600 grit. Thus, a napped artificial leather greige having a napped surface is produced by raising the fibers of the buffed surface to raise the ultrafine fibers. The greige of napped artificial leather is further dyed, kneaded and softened, dry-buffed and softened, reverse-sealed brushing, antifouling, hydrophilic, lubricant, softener, and antioxidant. Finishing treatments such as agent treatment, ultraviolet absorber treatment, and fluorescent agent treatment may be performed.

The thickness of the greige of the napped artificial leather is approximately equal to the thickness of the finally obtained napped artificial leather. Specifically, the thickness of the greige of the napped artificial leather is 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, more preferably 0.4 to 1.0 mm. When the thickness of the greige of the napped 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 phosphorus-based flame retardant particles and a second polyurethane on the back surface of the main surface of the napped artificial leather greige having a thickness of 0.25 to 1.5 mm. It can be obtained by performing a flame-retardant treatment, which is a treatment in which a resin liquid is unevenly distributed in a range of 200 μm or less in thickness from the back surface. Here, in the napped artificial leather of the present embodiment, the fact that the phosphorus-based flame retardant particles are unevenly distributed in a range of 200 μm or less in thickness from the back surface with respect to the main surface means that most of the phosphorus-based flame retardant particles present in the napped artificial leather, specifically Specifically, it means that 90 to 100% by mass, further 95 to 100% by mass of the phosphorus-based flame retardant particles are present in a range of 200 μm or less in thickness from the back surface to the main surface. The thickness from the back surface to the main surface where the phosphorus-based flame retardant particles are unevenly distributed 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 of the napped artificial leather in a direction parallel to the thickness direction with a scanning electron microscope.

In this way, phosphorus is added to a range of 200 μm or less in thickness from the back surface of the napped surface of the napped artificial leather so that the content ratio of the phosphorus-based flame retardant particles is 1 to 6% by mass in terms of phosphorus atoms. By unevenly distributing the flame retardant particles, it is possible to impart a high level of flame retardancy using a non-halogen flame retardant without impairing the surface's luxurious feel.

The content of the phosphorus-based flame retardant particles unevenly distributed in a range of 200 μm or less in thickness from the back surface to the napped surface of the main surface in the napped artificial leather is 1 to 6% by mass in terms of phosphorus atoms, preferably 1.5. ~5.5% by mass. If the content of the phosphorus-based flame retardant particles in the napped artificial leather is less than 1% by mass in terms of phosphorus atoms, a high level of flame retardancy cannot be obtained. In addition, when the content of the phosphorus-based flame retardant particles in the napped artificial leather exceeds 6% by mass in terms of phosphorus atoms, the phosphorus-based flame retardant particles are fixed from the back surface to a thickness of 200 μm or less without falling off. This makes it difficult to unevenly distribute the fibers, and the softness of the napped artificial leather is lost, and the high-class feeling of the surface is lowered.

In addition, 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. The following are flame-retardant compounds containing phosphorus atoms that are particulate solids at room temperature and have a melting point or a decomposition temperature of 150° C. or higher in the absence of a melting point.

The average particle size of the phosphorus flame retardant particles is 0.1 to 30 μm, preferably 0.5 to 10 μm, more preferably 1 to 5 μm. When the average particle size exceeds 30 μm, the content ratio of the phosphorus-based flame retardant particles in the range of 200 μm or less from the back surface of the napped artificial leather is sufficient so that the content ratio in terms of phosphorus atoms is 1 to 6% by mass. It tends to be difficult to penetrate into the flame retardant effect, and the flame retardant effect tends to be insufficient. On the other hand, if the average particle size is less than 0.5 μm, the particles tend to agglomerate and disperse non-uniformly, resulting in 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, preferably 0.15% by mass or less. When 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 during production or use.

In addition, the phosphorus-based flame retardant particles have a hot water solubility of 5% by mass or less, or 3% by mass or less in hot water at 90 ° C. It is preferable from the viewpoint that it is difficult to bleed to the napped surface and that it is difficult to undergo dimensional change due to moisture absorption.

Further, the phosphorus-based flame retardant particles are particulate solids at room temperature having a melting point or a decomposition temperature of 150° C. or higher, preferably 200° C. or higher in the absence of a melting point. When the melting point or the decomposition temperature in the absence of a melting point is less than 150° C., it softens and solidifies due to drying or the like after treatment with the flame retardant, and is no longer in a particulate form. It is easy to damage the surface touch and texture. In addition, melt drops tend to occur during the combustion process, making it 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). Also, the thermal decomposition temperature in the absence of a melting point is specified by the decomposition initiation temperature by thermogravimetric differential thermal analysis (TG-DTA). The measurement conditions are not particularly limited, but the measurement is performed in a nitrogen atmosphere at a heating rate of 5 to 10° C./min.

The phosphorus-based flame retardant particles as described above are selected from, for example, organic phosphinate metal salts such as dialkylphosphinate metal salts and monoalkylphosphinate metal salts; aromatic phosphonate esters; phosphoric acid ester amides and the like. These may be used alone or in combination of two or more. Among these, metal dialkylphosphinates and metal monoalkylphosphinates are preferred because of their high water resistance and heat resistance, high phosphorus atom content, and high flame retardancy.

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, from the viewpoint of obtaining a supple texture and preventing the flame retardant from falling off.

A resin liquid containing phosphorus-based flame retardant particles and a second polyurethane is applied from the back surface to a thickness of 200 μm or less on the back surface of the main surface of the napped artificial leather greige with a thickness of 0.25 to 1.5 mm. is not particularly limited. Specifically, a treatment liquid containing phosphorous flame retardant particles and a second polyurethane is applied to the back surface of the main surface of the napped artificial leather against the napped surface by, for example, gravure coating, direct coating, roll coating, or spray coating. is applied while adjusting the coating amount and viscosity, and dried.

The viscosity of the treatment liquid containing the phosphorus-based flame retardant particles and the second polyurethane is 200 to 10000 mPa·sec, preferably 500 to 5000 mPa·sec. To moderately sink from the back surface of a raw fabric of a napped artificial leather and easily unevenly distribute in a range of 200 μm or less in thickness, thereby imparting high flame retardancy without impairing the luxury of the napped surface which is the main surface. It is preferable from the point that

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. be done. In the case of a polyurethane emulsion, the average particle size of the emulsion is preferably 10 μm or less, more preferably 5 μm. Although the drying temperature of the resin liquid is not particularly limited, it is usually preferably from 100 to 160.degree.

The content 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, particularly 15 to 25% by mass in terms of phosphorus atoms. %. When the content of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the second polyurethane is within the above range, it is preferable because the flame retardancy is less affected by combustion of the second polyurethane.

In addition, the content 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% by mass in terms of phosphorus atoms, and the content of the phosphorus-based flame retardant particles The mass is preferably 60 to 90% by mass, more preferably 70 to 85% by mass.

In addition, the ratio of the second polyurethane contained in the napped artificial leather is not particularly limited, but it is 2 to 15% by mass, further 4 to 10% by mass. It is preferable from the viewpoint that the phosphorus-based flame retardant particles can be sufficiently fixed while reducing the .

When the ultrafine fibers form a fiber bundle derived from sea-island composite fibers, the polyurethane may be impregnated inside the fiber bundle or adhered to the outside of the fiber bundle. When the islands-in-the-sea composite fiber is treated to form microfibers, the thermoplastic resin of the sea component is removed from the islands-in-the-sea composite fiber to form voids inside the microfiber bundle. For this reason, the second polyurethane applied after the islands-in-the-sea composite fiber has been treated to form microfibers tends to impregnate the inside of the fiber bundle and bind the microfibers forming the fiber bundle. Therefore, the second polyurethane impregnated in the ultrafine fiber bundles constrains the ultrafine fiber bundles and contributes to improving the shape retention of the fiber entangled body.

The ratio of the total amount of polyurethane containing the first polyurethane and the second polyurethane contained in the napped artificial leather is not particularly limited, but it is 2 to 40% by mass, further 5 to 35% by mass. It is preferable from the point that the influence of the flame retardance deterioration due to the combustion of can be reduced.

Further, the content of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles and the polyurethane containing the first polyurethane and the second polyurethane is preferably 5 to 20% by mass in terms of phosphorus atoms, Furthermore, 6 to 20% by mass is preferable from the viewpoint of excellent balance between flame retardancy and flexibility 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 , particularly 10 to 50 g/m ² . It is preferable from the point of obtaining a napped artificial leather having a particularly excellent balance between self-extinguishing properties and surface luxury.

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

The napped artificial leather of the present embodiment thus obtained has a basis weight of 150 to 600 g/m ² , more preferably 170 to 400 g/m ² , so as to sufficiently maintain high flame retardancy, Phosphorus-based flame retardant particles are preferable because they do not easily affect the appearance and feel of the napped surface, and are less likely to reduce the surface luxury feeling.

The thickness of the napped artificial leather is 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, more preferably 0.4 to 1.0 mm. If the thickness of the napped artificial leather is less than 0.25 mm, the flame retardant is likely to be exposed on the surface, resulting in deterioration of surface quality and touch. Moreover, when the thickness of the napped artificial leather exceeds 1.5 mm, the flame retardancy is lowered.

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

The napped artificial leather of the present embodiment is preferably used, for example, as a wallcovering material in which the napped artificial leather and an interior base material (back board) are bonded together with a composite adhesive. Specific examples of interior base materials include concrete, brick, tile, ceramic tile, fiber reinforced cement board, glass fiber mixed cement board, calcium silicate board, steel, aluminum, metal plate, glass, mortar, plaster, Stone, gypsum board, rock wool, glass wool board, wood wool cement board, hard wood wool cement board, wood wool cement board, pulp cement board, flame-retardant plywood and the like. Among these, concrete, brick, tile, ceramic tile, fiber reinforced cement board, glass fiber mixed cement board, calcium silicate board, iron and steel, aluminum, A metal plate and glass are preferred.

Examples of composite adhesives 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, and silicone-based adhesives. Fluorine-based adhesives, copolymers or mixtures thereof, or adhesives mixed with metal compounds such as metal salts and hydroxides. Among these, starch-based, (alkyl) cellulose-based, vinyl acetate-based, chloroprene-based, phenol-based, nitrile-based, fluorine-based, silicone-based and these Copolymers, mixtures, and adhesives containing metal salts or hydroxides are included.

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

The composite material obtained by bonding the interior base material to the back surface of the napped artificial leather of this embodiment with an adhesive has a total calorific value (THR) of 10 MJ/m ² or less, or 8 MJ/m ² or less. It is possible. In addition, the composite material of the present embodiment can realize a composite material having a maximum heating value (PHRR) of 250 kW/m ² or less, further 200 kW/m ² or less. In addition, the composite material of this embodiment can realize a composite material having a maximum average rate of heat dissipation (MARHE; kW/m ² ) of 90 kW/m ² or less.

In addition, the napped artificial leather of the present embodiment has a high level of flame retardancy, a surface luxury feeling, a supple texture, and a sense of fulfillment. It is preferably used for applications that require a high level of flame retardancy such as self-extinguishing, low heat generation and low smoke emission, such as materials for seats and sofas in public buildings such as hotels and department stores, and interior decoration such as walls.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the scope of the present invention is not limited at all by 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 melting of the islands-in-the-sea composite fiber. Specifically, molten resins of the sea component resin and the island component resin are supplied to a composite spinning nozzle having nozzle holes for forming a cross section in which 25 island component resins are distributed in the sea component resin. , the melted fibers of the islands-in-the-sea composite fiber were discharged from the nozzle hole. At this time, the supply was performed while adjusting the pressure so that the mass ratio of the sea component and the island component was sea component/island component=25/75.

Then, a sea-island composite fiber having a fineness of 3.3 dtex was spun by sucking and drawing the molten fiber of the sea-island composite fiber with a suction device. The spun sea-island composite fibers were continuously deposited on a movable net and lightly pressed with a heated metal roll to suppress surface fluffing. After peeling the sea-island composite fiber from the net, it 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-lapper device, 8 layers of the web were stacked so that the total basis weight was 300 g/m ² , and needle-punched alternately from both sides to entangle. The basis weight of the entangled web, which is the web after needle punching, was 440 g/m ² .

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

The shrunk entangled web was then impregnated with a first polyurethane emulsion containing ammonium sulfate as a gelling agent and then dried. The first polyurethane consists of a polymer polyol that is 100% polycarbonate-based polyol and has an average repeating carbon number of 6 excluding reactive functional groups, an organic polyisocyanate that is 4,4′-dicyclohexylmethane diisocyanate, and chain extension. It was a self-emulsifying amorphous polycarbonate urethane which was a reaction product with 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, thereby producing a nonwoven fabric in which fiber bundles containing 25 ultrafine fibers having a fineness of 0.1 dtex are three-dimensionally entangled. A greige of artificial leather containing The content of the first polyurethane in the artificial leather greige was 12% by mass.

Then, the artificial leather greige was sliced into two parts in the thickness direction, and the non-sliced surface was buffed to finish a napped artificial leather greige having a suede-like napped surface. The greige of 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, using a circular dyeing machine, the raw fabric of the plush artificial leather was dyed, dried, impregnated with a softening agent, and further dried.

Then, on the sliced surface of the napped artificial leather raw fabric after dyeing, using a gravure coating machine equipped with a 35-mesh gravure roll, particles of dialkylphosphinate metal salt, which is a phosphorus-based flame retardant, are dispersed at a pressure of 2000 mPa / sec. After coating the second polyurethane emulsion in an amount of 110 g/m ² , the moisture content was dried at 120°C. The particles of the dialkylphosphinate metal salt had a dispersed particle diameter (median diameter: D ₅₀ ) of 4 µm as measured by a laser diffraction/scattering particle size distribution analyzer, and a phosphorus atom content of 23.5% by mass. , a solubility in water at 30°C of less than 0.2% by mass, and a melting point and decomposition temperature of greater than 250°C.

Also, the second polyurethane emulsion contained 10% by weight of the second polyurethane and 28% by weight of the dialkylphosphinate metal salt. The second polyurethane comprises a polymer polyol that is 100% polycarbonate-based 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 forced emulsification type amorphous polycarbonate urethane which was a reaction product with a chain extender and had a 100% modulus of 1.0 MPa.

Then, the flame retardant napped artificial leather raw machine 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 (longitudinal direction), and then the surface is sealed. to obtain a napped artificial leather having a suede-like napped surface. 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 dialkylphosphinate metal salt particles. As a result, the napped artificial leather contained 2.6% by mass of dialkylphosphinic acid metal salt in terms of phosphorus atom content. Also, the mass % in terms of phosphorus atoms with respect to the total amount of the dialkylphosphinate metal salt particles, the first polyurethane and the second polyurethane was 10.3 mass %. Also, the mass % in terms of phosphorus atoms with respect to the total amount of the second polyurethane and the particles of the dialkylphosphinate metal salt was 17.3 mass %.

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

(Luxury surface)
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 feeling 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 the quality was inferior.
D: Phosphorus-based flame retardant particles bleed during storage and the surface was whitened.

(thickness, basis weight, apparent density)
According to JIS L1913, the thickness (mm) and basis weight (g/cm ² ) of the napped artificial leather are measured, and the apparent density (g/cm ³ ) is calculated by dividing the basis weight by the thickness. bottom.

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

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

(Vertical combustion test: self-extinguishing property)
The vertical method flame retardancy of the napped artificial leather was measured according to the FAR25 Appendix F Part 1(a)(1)(ii) combustion test standard for aircraft interior materials. Specifically, a napped artificial leather was cut into a size of 50.8 mm×304.8 mm to prepare a test piece. The test piece was then fixed vertically to the sample holder of the combustion test apparatus. A burner was placed just below one end of the test piece, and after 12 seconds of indirect flame, the test piece's burning distance, self-extinguishing time, and drop self-extinguishing time were measured. An average of n=10 was calculated.

(Horizontal combustion test)
The suede-like artificial leather was subjected to a horizontal combustion test according to the FMVSS302 combustion test standard. Specifically, a suede-like artificial leather was cut into a size of 102 mm×356 mm, and a test piece was prepared by drawing a reference line 38 mm from one end of the sample. Then, the test piece was horizontally fixed to the sample holder of the combustion test apparatus. A burner was placed at the end of the sample on the marked side of the test piece and flamed for 15 seconds, after which the burning distance and burning time of the test piece were measured. An average of n=10 was calculated. Self-extinguishing before the marked line (SE), self-extinguishing when the burning distance is 50 mm or less and the burning time is 60 seconds or less beyond the marked line, slow burning when the burning speed is 100 mm/min or less, and burning speed. 100 mm/min or more was defined as flammable.

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 dialkylphosphinate metal salt, 22% by weight of the second polyurethane and 28% by weight of the dialkylphosphine 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. Table 1 shows the results.

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

[Example 4]
In Example 1, instead of applying the second polyurethane emulsion in which particles of a dialkylphosphinate metal salt, which is a phosphorus-based flame retardant, were dispersed so as to be 110 g/m ² , it was applied so as to be 60 g/m ² . A napped artificial leather was obtained and evaluated in the same manner, except for the above. Table 1 shows the results.

[Example 5]
Instead of the nonwoven fabric in which fiber bundles containing 25 ultrafine fibers of 0.1 dtex are three-dimensionally entangled in Example 1, a nonwoven fabric is formed in which fiber bundles containing 6 ultrafine fibers of 0.4 dtex are three-dimensionally entangled. bottom. 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) was 60/40. It is a reaction product of a polymer polyol having an average repeating 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. Furthermore, the monoalkylphosphinate metal salts shown in Table 1 were used as phosphorus-based flame retardant particles instead of the dialkylphosphinate metal salts. Otherwise, the napped artificial leather was obtained and evaluated in the same manner as in Example 1. Table 1 shows the results.

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

[Example 7]
A napped artificial leather was obtained and evaluated in the same manner as in Example 1, except that the phosphoric acid ester amide shown in Table 1 was used instead of the dialkylphosphinate metal salt as the phosphorous-based flame retardant particles. Table 1 shows the results.

[Example 8]
Using polyethylene as the sea component resin and isophthalic acid-modified polyethylene terephthalate as the island component resin, the sea-island composite fiber was prevented from melting. Specifically, molten resins of the sea component resin and the island component resin are supplied to a composite spinning nozzle having nozzle holes for forming a cross section in which 25 island component resins are distributed in the sea component resin. , the melted fibers of the islands-in-the-sea composite fiber were discharged from the nozzle hole. At this time, the supply was performed while adjusting the pressure so that the mass ratio of the sea component and the island component was sea component/island component=25/75.

Then, a sea-island composite fiber was spun by sucking and drawing the molten fiber of the sea-island composite fiber with a suction device. The spun sea-island composite fibers were continuously deposited on a movable net and lightly pressed with a heated metal roll to suppress surface fluffing. After peeling the islands-in-the-sea 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-lapper device, 8 layers of the web were stacked so that the total basis weight was 320 g/m ² , and needle-punched alternately from both sides to entangle. Then, the entangled web was subjected to wet heat shrinkage for 30 seconds under conditions of 70° C. and 50% RH humidity.

Then, the shrunk entangled web is impregnated with an N,N-dimethylformamide solution of the first polyurethane, immersed in a mixed solution of N,N-dimethylformamide and water, coagulated, and then treated with toluene to form polyethylene. was extracted and dried. The first polyurethane has 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 reacts 100% modulus is 5 It was an amorphous polycarbonate urethane of 0.0 MPa.

Otherwise, the napped artificial leather was obtained and evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 9]
Using polyethylene as the sea component resin and 6-nylon as the island component resin, the sea-island composite fiber was prevented 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 a mixed spinning nozzle and discharged from a nozzle hole. The number of islands was about 600 on average, and a fiber of 5.5 dtex was obtained by drawing. The fibers were crimped, cut to 51 mm, and carded to obtain a staple fiber web having a basis weight of 100 g/m ² . A 6-layer laminated web was produced from this using a cross-lapper device, sprayed with an oil solution, needle-punched at 1,500 punches/cm ² , and hot-pressed to achieve an apparent density of 0.00. A fiber entangled body having a weight of 40 g/cm ³ and a thickness of 1.5 mm was obtained.
Then, the fiber entangled body was impregnated with an N,N-dimethylformamide solution of the first polyurethane, immersed in a mixed solution of N,N-dimethylformamide and water, solidified, and then polyethylene was extracted with toluene. Dried. The first polyurethane has 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 reacts 100% modulus is 5 .0 MPa polyurethane. 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 metal dyeing. Table 1 shows the results.

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

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

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

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

[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 instead of the dialkylphosphinate metal salt as the phosphorus-based flame retardant particles. Table 2 shows the results. The phosphorus-based flame retardant was treated in the form of an aqueous dispersion during the flame retardant treatment, but when observed on the napped artificial leather, it was turned into a resin film and was not in the form of particles.

[Comparative Example 5]
A napped artificial leather was obtained and evaluated in the same manner as in Example 4, except that the first polymeric elastomer was changed to polyether-based polyurethane (having an average repeating carbon number of 5 excluding the reactive functional group). Table 2 shows the results.

[Comparative Example 6]
In Example 4, the number of island components in the spinneret was changed from 25 to 4, ultrafine fibers with an average fineness of 0.6 dtex were used, and the first elastic polymer was polycarbonate-based polyurethane (reactive functional A napped artificial leather was obtained and evaluated in the same manner except that the repeating average carbon number was changed to 9) excluding the group. Table 2 shows the results.

Referring to Tables 1 and 2, all of the napped artificial leathers obtained in Examples 1 to 10 have a good surface luxury feeling, have a supple texture, and further have good self-extinguishing properties and emit smoke. It was a napped artificial leather with a low amount of heat and combustion heat, and a high level of flame retardancy. 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 to the inside, the phosphorus-based flame retardant is exposed on the surface and the surface luxury feeling is poor. was also inadequate. In addition, the napped artificial leather obtained in Comparative Example 2, in which ammonium polyphosphate was used as the phosphorus-based flame retardant particles, caused bleeding over time and was inferior in surface luxury. In addition, the napped artificial leather obtained in Comparative Example 3 was slightly inferior in flame retardancy, and bleeding occurred over time, resulting in inferior surface quality. Moreover, Comparative Example 4 in which the phosphorus-based flame retardant particles were changed to an aromatic phosphate ester had a hard texture and insufficient flame retardancy. Moreover, in Comparative Example 5, in which the fineness of the napped artificial leather was large and the basis weight was high, the flame retardancy was insufficient.

Claims (7)

A main surface which is a napped surface including a fiber entangled body containing ultrafine fibers having a fineness of 0.5 dtex or less, and polyurethane and phosphorus-based flame retardant particles impregnated in the fiber entangled body, and having the ultrafine fibers raised. A napped artificial leather with a thickness of 0.25 to 1.5 mm,
The polyurethane includes a first polyurethane that exists over the entire thickness cross section and a second polyurethane that is unevenly distributed in a range of 200 μm or less in thickness from the back surface with respect to the main surface,
90 to 100% by mass of the phosphorus-based flame retardant particles are attached to the second polyurethane,
The first polyurethane is a reaction product of a polymer polyol, an organic polyisocyanate, and a chain extender, and 60% by mass or more of the polymer polyol is a polycarbonate polyol, and a repeating average excluding reactive functional groups A polyurethane having a carbon number of 6.5 or less, wherein the organic polyisocyanate 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% by mass or more, a solubility in water at 30° C. of 0.2% by mass or less, and a melting point or when there is no melting point. The decomposition temperature is 150° C. or higher,
A napped artificial leather, wherein the content of the phosphorus-based flame retardant particles in the napped artificial leather is 1 to 6% by mass in terms of phosphorus atoms. 2. The content of the phosphorus-based flame retardant particles in the total amount of the phosphorus-based flame retardant particles , the first polyurethane, and the second polyurethane is 5 to 20% by mass in terms of phosphorus atoms . The napped artificial leather described in . The napped artificial leather according to claim 1 or 2, wherein the content 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. . 4. The phosphorus-based flame retardant particles according to any one of claims 1 to 3, wherein the phosphorus-based flame retardant particles contain at least one compound selected from the group consisting of organic phosphinic acid metal salts, aromatic phosphonic acid esters, and phosphoric acid ester amides. plush artificial leather. A composite material obtained by bonding an interior base material to the back surface of the napped artificial leather according to any one of claims 1 to 4 with an adhesive. The interior base material is concrete, brick, tile, ceramic tile, fiber reinforced cement board, glass fiber mixed cement board, calcium silicate board, steel, aluminum, metal plate, glass, mortar, plaster, stone, gypsum board, 6. The composite material according to claim 5, which is selected from the group consisting of 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. The adhesive is a mixture of starch-based, (alkyl)cellulose-based, vinyl acetate-based, chloroprene-based, phenol-based, nitrile-based, fluorine-based, silicone-based, copolymers and mixtures thereof, metal salts and hydroxides. 7. A composite material according to claim 5 or claim 6, selected from the group consisting of adhesives.