JP5223661B2 - Method for producing fiber sheet with polyurethane - Google Patents

Description

  The present invention relates to a method for producing a fiber sheet with polyurethane.

  A sheet-like material mainly composed of ultrafine fibers and polyurethane has excellent characteristics not found in natural leather, and is widely used in various applications. In particular, sheet-like materials using polyester-based ultrafine fibers are excellent in light resistance, and their use has spread year by year for clothing, chair upholstery, automotive interior materials, and the like.

  In producing such a sheet-like material, a step of treating a nonwoven fabric composed of ultrafine fiber-expressing fibers with an organic solvent to express ultrafine fibers, and impregnating the nonwoven fabric with an organic solvent solution of polyurethane, the fiber sheet shape A combination of steps in which a polyurethane is wet-coagulated by immersing the product in water or an organic solvent aqueous solution which is a non-solvent for polyurethane is generally employed. As such an organic solvent, toluene, trichloroethylene or the like is used in the fiber ultrafine process, and a water-miscible organic solvent such as N, N-dimethylformamide is used as the organic solvent for polyurethane. However, since organic solvents are generally highly harmful to the human body and the environment, there is a strong demand for methods that do not use organic solvents in the production of sheet-like materials.

  As a specific solution, for example, regarding the fiber ultrafine process, by using an alkaline aqueous solution soluble component, hot water soluble component, or the like for the ultrafine fiber expression type fiber, the ultrafine fiber can be obtained using an alkaline aqueous solution, hot water, or the like. With regard to the use of an organic solvent for polyurethane, a method of using a polyurethane water dispersion in which polyurethane is dispersed in water instead of the conventional organic solvent type polyurethane has been studied.

  Here, paying attention to the application of the polyurethane water dispersion, generally, the impregnation step of the polyurethane water dispersion is in the order of impregnation, dry coagulation, and drying, but the fiber sheet is simply impregnated with the polyurethane water dispersion. When dry-solidified, a migration phenomenon occurs in which polyurethane moves and concentrates on the surface of the impregnated fiber sheet. Since the texture of the fiber sheet becomes very hard when the migration phenomenon occurs, a technique for suppressing the migration phenomenon has been studied. For example, addition of a heat-sensitive gelling agent to an aqueous polyurethane dispersion can be mentioned. Thermal gelation is the property that polyurethane water dispersion loses fluidity and solidifies when heated above a certain temperature. Thermal gelling agent gives such properties to polyurethane water dispersion. It is an additive.

  It is disclosed that the migration phenomenon at the time of drying of the polyurethane liquid impregnated in the fiber base material is suppressed by imparting heat-sensitive gelling property to the polyurethane liquid.

  For example, in Patent Document 1, a directly spun ultrafine fiber is made into a non-woven fabric by a papermaking method, and then impregnated with a polyurethane water dispersion added with sodium sulfate as a heat-sensitive gelling agent. By adding sodium sulfate, the dispersibility of the polyurethane emulsion can be destabilized, and heat migration gelation is imparted to the polyurethane to suppress the migration phenomenon. However, it is not possible to sufficiently suppress the migration phenomenon. Therefore, it is inevitable that the uneven distribution of polyurethane adhesion in the thickness direction is unavoidable, and the texture of the sheet-like material and the surface quality after the raising treatment are sufficient. Could not be improved. In addition, the method of adding an inorganic salt inhibits the hydration state of the polyurethane emulsion and lowers the stability of the emulsion, and there is a problem in the storage stability of the polyurethane liquid.

Patent Document 2 discloses a migration suppression technique in which a nonionic surfactant and an inorganic salt are combined. By using a nonionic surfactant in combination, the polyurethane liquid can be thickened at a temperature equal to or higher than the cloud point by utilizing the cloud point of polyethylene glycol, and a synergistic effect in combination with an inorganic salt is aimed at. However, complete migration suppression was not possible.
Japanese Patent No. 3166054 JP 2000-96457 A

  An object of the present invention is to provide a polyurethane-attached fiber sheet-like material that suppresses the migration phenomenon while using a water-dispersed polyurethane that has a low environmental burden and is excellent in appearance and texture.

That is, the present invention includes the step of applying a polyurethane solution on the fiber base material, water-dispersed polyurethane liquid der which the polyurethane liquid contains a radical reaction initiator is, water-dispersible polyurethane nonionic self-emulsifiable polyurethane a method for producing a polyurethane with fiber sheet, characterized in der Rukoto.

  ADVANTAGE OF THE INVENTION According to this invention, the migration phenomenon can be suppressed and the fiber sheet-like article with a polyurethane excellent in the external appearance and the texture can be obtained, using the water dispersion type polyurethane with a little burden on an environment.

  Examples of fibers constituting the fiber base material include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyester such as polylactic acid, polyamide such as 6-nylon and 66-nylon, acrylic, polyethylene, polypropylene, thermoplastic cellulose, and the like. A thermoplastic resin that can be melt-spun can be used. Among these, polyester is preferably used from the viewpoint of strength, dimensional stability, and light resistance. Further, the fiber base material may be configured by mixing fibers of different materials.

  The cross-sectional shape of the fiber may be a round cross section, but may be a polygonal shape such as an ellipse, a flat shape, or a triangle, or a deformed cross section such as a sector shape or a cross shape.

  As an average fiber diameter of the fiber which comprises a fiber base material, 0.3-25 micrometers is preferable. By making the thickness 25 μm or less, preferably 22 μm or less, more preferably 20 μm or less, it becomes easy to produce a nonwoven fabric by needle punching. On the other hand, by making it 0.3 μm or more, preferably 0.7 μm or more, more preferably 1 μm or more, coloring property after dyeing, dispersibility of bundled fibers during napping treatment such as grinding with sandpaper, etc., ease of spreading. Excellent.

  It is also preferable to use ultrafine fiber expression type fibers. By doing so, the form which the fiber bundle mentioned later intertwined can be obtained stably.

  As ultra-fine fiber expression type fiber, two-component thermoplastic resins with different solvent solubility are used as sea component / island component, and island component is made into ultra-fine fiber by dissolving and removing the sea component using solvent etc. Alternatively, a two-component thermoplastic resin may be alternately disposed in a radial or multilayer manner on the fiber cross section, and a peelable composite fiber that is split into ultrafine fibers by separating and separating each component may be employed. Among these, the sea-island type fibers are preferable also from the viewpoint of flexibility and texture of the sheet-like material because an appropriate void can be provided between the island components, that is, between the ultrafine fibers, by removing the sea component.

  Sea-island type fibers include sea-island type composite bases, sea-island type composite fibers that are spun by arranging the sea and island components in mutual alignment, and mixed spinning fibers that are spun by mixing the two components of the sea and islands. However, sea-island type composite fibers are more preferable because ultrafine fibers with uniform fineness can be obtained, and because a sufficiently long ultrafine fiber can be obtained and contribute to the strength of the sheet-like material.

  As the sea component of the sea-island fiber, polyethylene, polypropylene, polystyrene, copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid or polyethylene glycol, polylactic acid, or the like can be used. Of these, copolymerized polyester or polylactic acid obtained by copolymerizing alkali-decomposable sodium sulfoisophthalic acid or polyethylene glycol, which can be decomposed without using an organic solvent, is preferable.

  The average single fiber diameter of the fiber obtained from the island component of the sea-island fiber is preferably 0.3 to 7 μm. By setting the thickness to 7 μm or less, preferably 6 μm or less, more preferably 5 μm or less, it is possible to obtain a sheet-like product having excellent flexibility and napping quality. On the other hand, by making it 0.3 μm or more, preferably 0.7 μm or more, more preferably 1 μm or more, coloring property after dyeing, dispersibility of bundled fibers during napping treatment such as grinding with sandpaper, etc., ease of spreading. Excellent.

  As the form of the fiber base material, a woven fabric, a knitted fabric, or a non-woven fabric can be adopted. Especially, since the surface quality of the sheet-like thing at the time of surface raising treatment is favorable, a nonwoven fabric is preferable.

  As the nonwoven fabric, either a short fiber nonwoven fabric or a long fiber nonwoven fabric may be used, but a short fiber nonwoven fabric is preferable in terms of texture and quality.

  The fiber length of the short fibers in the short fiber nonwoven fabric is excellent in wear resistance due to entanglement by being 25 mm or more. Moreover, it is excellent in a texture and quality by setting it as 90 mm or less.

  When the fiber base material is a nonwoven fabric, it is preferable that a bundle of fibers (fiber bundle) is entangled. Since the fibers are intertwined in a bundle state, the strength of the sheet is improved. The nonwoven fabric of this aspect can be obtained by entanglement of the ultrafine fiber-expressing fibers in advance and allowing the ultrafine fibers to develop.

  A needle punch or a water jet punch can be employed as a method of entanglement of fibers or fiber bundles in the nonwoven fabric.

  When the fiber base material is a non-woven fabric, a woven fabric or a knitted fabric may be inserted for the purpose of improving the strength. The average fiber diameter of the fibers constituting the woven or knitted fabric is preferably about 0.3 to 10 μm.

  The sea removal treatment when sea-island fibers are used may be performed before or after application of polyurethane to the fiber base material. If the sea removal treatment is performed before the polyurethane is applied, the polyurethane is in close contact with the ultrafine fibers so that the ultrafine fibers can be strongly held, so that the wear resistance of the sheet is improved. On the other hand, when sea removal treatment is performed after polyurethane is applied, voids are generated between the polyurethane and the ultrafine fibers due to the sea components removed from the sea, so the polyurethane is not directly gripped by the polyurethane and the texture of the sheet is flexible. It becomes.

  The sea removal treatment can be performed by immersing the sea-island fiber in a solvent and squeezing it.

  As the solvent for dissolving the sea component, an organic solvent such as toluene or trichloroethylene in the case of polyethylene, polypropylene or polystyrene, or an alkaline aqueous solution such as sodium hydroxide in the case of copolymerized polyester or polylactic acid can be used.

  As the polyurethane used in the present invention, those obtained by reaction of a polymer diol, an organic diisocyanate and a chain extender are preferable.

  As the polymer diol, polycarbonate-based diol, polyester-based diol, polyether-based diol, silicone-based diol, and fluorine-based diol can be adopted, and a copolymer obtained by combining these may be used. Of these, polycarbonate diols and polyether diols are preferably used from the viewpoint of hydrolysis resistance, and polycarbonate diols and polyester diols are preferable from the viewpoint of light resistance and heat resistance. From the viewpoint of all the balance of hydrolysis resistance, heat resistance, and light resistance, polycarbonate diols and polyester diols are more preferable, and polycarbonate diols are particularly preferable.

  The polycarbonate-based diol can be produced by an ester exchange reaction between an alkylene glycol and a carbonate ester, or a reaction between phosgene or chloroformate ester and an alkylene glycol.

  Examples of the alkylene glycol include linear chains such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol. Alkylene glycol, branched alkylene glycol such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol, Examples include alicyclic diols such as 4-cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylolpropane, and pentaerythritol. Either a polycarbonate diol obtained from a single alkylene glycol or a copolymerized polycarbonate diol obtained from two or more alkylene glycols may be used.

  In addition, if the alkylene part of the alkylene glycol has a branched structure, radicals generated by light or heat deterioration are likely to be generated in the alkyl group of the branch part, which may cause light / heat deterioration of the polyurethane. More preferably, the alkylene moiety is linear. Further, when the alkylene part of the alkylene glycol has a linear structure, the crystallinity of the polyurethane is improved, and the flexibility of the polyurethane tends to be hardened. Polycarbonate diol composed of 1,4-butanediol and 1,5-pentanediol, or polycarbonate diol composed of 1,5-pentanediol and 1,6-hexanediol is particularly preferred.

  Examples of the polyester diol include polyester diols obtained by condensing various low molecular weight polyols and polybasic acids.

  Examples of the low molecular weight polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-propane. Diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, cyclohexane One or more selected from -1,4-dimethanol can be used. Further, addition products obtained by adding various alkylene oxides to bisphenol A can also be used.

  Examples of the polybasic acid include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydroisophthalic acid. One kind or two or more kinds selected from acids may be mentioned.

  Examples of the polyether-based diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymer diols obtained by combining them.

  The number average molecular weight of the polymer diol is preferably 500 to 4000. When the number average molecular weight is 500 or more, more preferably 1500 or more, the texture is prevented from becoming hard, and when it is 4000 or less, more preferably 3000 or less, the strength as polyurethane can be maintained.

  Examples of the organic diisocyanate include aliphatic systems such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and xylylene diisocyanate, and aromatic systems such as diphenylmethane diisocyanate and tolylene diisocyanate, and these may be used in combination. Of these, aliphatic systems such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferable from the viewpoint of light resistance.

  As the chain extender, amines such as ethylenediamine and methylenebisaniline and diols such as ethylene glycol can be used. Moreover, you may use the polyamine obtained by making polyisocyanate and water react as a chain extender.

  The weight average molecular weight of the polyurethane is preferably 100,000 or more and 600,000 or less. By setting the weight average molecular weight to 100,000 or more, more preferably 150,000 or more, the wear resistance of the sheet-like material is improved. Moreover, by making it 600,000 or less, more preferably 500,000 or less, an increase in the viscosity of the polyurethane liquid can be suppressed, and the nonwoven fabric can be easily impregnated.

  Polyurethane may be used in combination with a crosslinking agent for the purpose of improving water resistance, abrasion resistance, hydrolysis resistance and the like. The cross-linking agent may be an external cross-linking agent added as a third component to the polyurethane, or may be an internal cross-linking agent that introduces a reaction point that becomes a cross-linked structure in advance in the polyurethane molecular structure. It is more preferable to use an internal crosslinking agent from the viewpoint that the crosslinking points can be formed more uniformly in the polyurethane molecular structure and the reduction in flexibility can be reduced.

  As the crosslinking agent, a compound having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, or the like can be used. However, when the crosslinking proceeds excessively, the polyurethane tends to harden and the texture of the sheet-like material also tends to harden. Therefore, those having a silanol group are preferred in terms of the balance between reactivity and flexibility. When a silanol group is introduced into the polyurethane molecular structure as an internal cross-linking agent, the polyurethane impregnated and solidified in the internal space of the nonwoven fabric has a cross-linked structure due to siloxane bonds, while maintaining the texture of the sheet-like material. Durability such as hydrolysis resistance can be dramatically improved.

  The polyurethane used in the present invention preferably has a hydrophilic group in the molecular structure. By doing so, the dispersion and stability of the water-dispersed polyurethane can be improved.

  Hydrophilic groups include cationic systems such as quaternary amine salts, anionic systems such as sulfonates and carboxylates, nonionic systems such as polyethylene glycol, and combinations of cationic systems and nonionic systems, and combinations of anionic systems and nonionic systems. Either of these can be adopted.

  Of these, nonionic compounds that are free from yellowing caused by light and harmful effects caused by a neutralizing agent are particularly preferable.

  That is, when an anionic system is used, a neutralizing agent is required. For example, when the neutralizing agent is a tertiary amine such as ammonia, triethylamine, triethanolamine, triisopropanolamine, trimethylamine, or dimethylethanolamine. The amine is generated and volatilized by heat during film formation and drying, and released outside the system. Therefore, it is indispensable to introduce an apparatus for recovering volatile amines in order to suppress atmospheric emissions and work environment deterioration. In addition, if amine does not volatilize by heating and remains in the final product sheet, it may be discharged to the environment when the product is incinerated, but nonionics do not use a neutralizing agent. Further, it is not necessary to introduce an amine recovery device, and there is no fear of residual amine in the sheet. Further, when the neutralizing agent is an alkali metal such as sodium hydroxide, potassium hydroxide or calcium hydroxide, or a hydroxide of an alkaline earth metal, the polyurethane part becomes alkaline when wetted with water. Since the nonionic system does not use a neutralizing agent, there is no need to worry about deterioration due to hydrolysis of polyurethane.

  It is important that the polyurethane liquid used in the present invention is a water-dispersed polyurethane liquid dispersed and stabilized in water. Water-dispersed polyurethane is a forced emulsification type polyurethane that is forcibly dispersed and stabilized using a surfactant, and has a hydrophilic structure in the polyurethane molecular structure and is dispersed in water even when no surfactant is present. -It is classified as a self-emulsifying polyurethane that stabilizes. Any of these may be used in the present invention, but self-emulsifying polyurethane is more preferable in that it does not contain a surfactant. When a forced emulsification type polyurethane containing a surfactant is used, the surfactant causes the stickiness of the surface of the sheet-like material and the like, and a cleaning step is required, which increases the processing steps and leads to an increase in cost. Further, since the water resistance of the polyurethane film formed into a film is lowered due to the presence of the surfactant, there is a tendency for the polyurethane to fall into the dyeing liquid in the dyeing of the fiber sheet with polyurethane. The self-emulsifying polyurethane also has an advantage that a remarkable coagulation effect of the polyurethane can be obtained upon heating in combination with a radical reaction initiator described later.

  It is important that the polyurethane liquid used in the present invention contains a radical reaction initiator. A radical reaction initiator refers to a substance that decomposes to generate radicals by stimulation with heat, light, or the like. By adopting a radical reaction initiator, it is possible to impart heat-sensitive gelling properties that are faster in response to polyurethane than inorganic salts such as nonionic surfactants and sodium sulfate, and to suppress migration. As its mechanism, polyethylene glycol in the polyurethane molecular structure or polyethylene glycol, which is a nonionic surfactant in the polyurethane liquid, is attacked and decomposed by radicals generated by thermal decomposition of the radical reaction initiator. This is presumed to be because it cannot be stably dispersed in water and suddenly loses fluidity and solidifies.

  Examples of the radical reaction initiator include inorganic compounds such as persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate, azo compounds such as azobisisobutyronitrile, and organic compounds such as benzoyl peroxide and triethylborane. Can be mentioned. Among them, persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate are preferable because they are water-soluble radical reaction initiators and can be easily mixed with the water-dispersed polyurethane liquid.

  Further, by using a radical reaction initiator, gelation does not start unless the temperature reaches a temperature at which the radical reaction initiator decomposes, and the stability of the polyurethane liquid is excellent.

  For example, according to a reference example to be described later, it is presumed that polyoxyethylene chain hydrogen abstraction reaction and open chain reaction occur due to ammonium persulfate, which is a radical reaction initiator, to destabilize the dispersibility of the aqueous polyurethane resin.

  Furthermore, when a radical reaction initiator is used in combination, once the polyurethane is solidified and the fluidity is lost, the fluidity will not be restored again and the solidification stability will be improved, and the occurrence of migration phenomenon due to reflowing will be suppressed. It is excellent in operational stability. On the other hand, when nonionic surfactants, inorganic salts, etc. are used as heat-sensitive gelling agents, when polyurethane is solidified by heating and then cooled to near room temperature, the fluidity is restored. If not dried, a migration phenomenon occurs due to reflow.

  The heat-sensitive gelation temperature of the polyurethane liquid is preferably 40 ° C. or higher and 90 ° C. or lower. By setting the temperature to 40 ° C. or higher, stability during storage of the polyurethane liquid is improved, and adhesion of polyurethane to the machine during operation can be suppressed. Moreover, the migration phenomenon of the polyurethane in a fiber base material can be suppressed by setting it as 90 degrees C or less.

  Polyurethane liquids are various additives such as pigments such as carbon black, flame retardants such as phosphorus, halogen, silicone, and inorganic, antioxidants such as phenol, sulfur, and phosphorus, benzotriazole, and benzophenone. -Based, salicylate-based, cyanoacrylate-based, oxalic acid-anilide-based UV absorbers, hindered amine-based, benzoate-based light stabilizers, polycarbodiimide-based hydrolysis stabilizers, plasticizers, antistatic agents, interfaces Activators, softeners, water repellents, coagulation regulators, dyes, preservatives, fillers such as cellulose particles, inorganic particles such as silica and titanium oxide, and the like may be contained.

  The polyurethane liquid may contain a water-soluble organic solvent in an amount of 40% by mass or less based on the polyurethane liquid in order to improve storage stability and film forming property. The content of is preferably 1% by mass or less.

  A polyurethane liquid can be impregnated and coated on a fiber substrate, and can be coagulated by dry heat coagulation, wet heat coagulation, wet coagulation, or these.

  The temperature of wet heat coagulation may be higher than the heat-sensitive gelation temperature of polyurethane, and for example, 40 ° C. or higher and 200 ° C. or lower is preferable. By setting the temperature to 40 ° C. or higher, more preferably 80 ° C. or higher, the time to solidification of polyurethane can be shortened to suppress the migration phenomenon. On the other hand, thermal degradation of polyurethane can be prevented by setting the temperature to 200 ° C. or lower, more preferably 160 ° C. or lower.

  The temperature of wet coagulation in hot water should just be more than the heat-sensitive gelation temperature of a polyurethane, for example, 40 degreeC or more and 100 degrees C or less are preferable. By setting the temperature to 40 ° C. or higher, more preferably 80 ° C. or higher, the time to solidification of polyurethane can be shortened to suppress the migration phenomenon.

  The dry solidification temperature and the drying temperature are preferably 80 to 160 ° C. Productivity is excellent by setting it as 80 degreeC or more, More preferably, it is 90 degreeC or more. On the other hand, the heat deterioration of polyurethane can be prevented by setting it to 180 ° C. or lower, more preferably 160 ° C. or lower.

  The ratio of the elastic resin binder containing polyurethane to the sheet is preferably 10 to 80% by mass. By setting the content to 10% by mass or more, more preferably 15% by mass or more, it is possible to obtain sheet strength and to prevent the fibers from dropping off. Moreover, by setting it as 80 mass% or less, More preferably, it is 70 mass% or less, it can prevent that a texture becomes hard and can obtain the target good nap quality.

  After application of the elastic resin binder, it is preferable that the sheet-like material is divided into half or several sheets in the sheet thickness direction because of excellent production efficiency.

  A lubricant such as a silicone emulsion may be applied before the raising treatment described later. Moreover, it is preferable to apply the antistatic agent before the raising treatment in order to make it difficult for the grinding powder generated from the sheet-like material to be deposited on the sandpaper by grinding.

  Raising treatment may be performed to form napping on the sheet surface. The raising treatment can be performed by a method of grinding using sandpaper or a roll sander.

  The sheet material may be dyed. As a dyeing method, it is preferable to use a liquid dyeing machine because the sheet-like material can be softened by dyeing the sheet-like material and at the same time giving a stagnation effect.

  If the dyeing temperature is too high, the polyurethane may be deteriorated. Conversely, if the dyeing temperature is too low, the dyeing to the fiber becomes insufficient. Therefore, it may be set depending on the type of the fiber, and generally 80 ° C. or higher and 150 ° C. or lower is preferable. 110 ° C. or higher and 130 ° C. or lower is more preferable.

  The dye may be selected in accordance with the type of fiber constituting the fiber substrate. For example, disperse dyes may be used for polyester fibers, and acid dyes and metal-containing dyes may be used for polyamide fibers, and combinations thereof. it can. When dyed with disperse dyes, reduction washing may be performed after dyeing.

It is also preferable to use a dyeing assistant during dyeing. By doing so, the uniformity and reproducibility of dyeing can be improved.
It is also preferable to perform a finishing treatment using a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, a light proofing agent or the like after the same bath as the dyeing or after dyeing.

  The sheet-like material of the present invention may be composed of a non-woven fabric in which fiber bundles of ultrafine fibers are entangled and an elastic resin binder mainly composed of polyurethane present in the internal space.

  The sheet-like material may contain functional agents such as dyes, pigments, softeners, texture modifiers, anti-pilling agents, antibacterial agents, deodorants, water repellents, flame retardants, light proofing agents, and weathering agents. Good.

  The fiber sheet with polyurethane obtained by the production method of the present invention has an excellent surface appearance such as suede like natural leather, nubuck, silver surface, etc., and preferably has a smooth surface appearance such as suede or nubuck. With a good touch and excellent lighting effects.

[Evaluation method]
(1) Average fiber diameter A scanning electron microscope (SEM) photograph of the surface of a nonwoven fabric or sheet-like material was taken at a magnification of 2000 times, 100 circularly or nearly elliptical fibers were randomly selected, and the fiber diameter was measured. Then, the average value was calculated.
In addition, when the ultrafine fiber which comprises a nonwoven fabric has an irregular cross section, the outer periphery circular diameter of an irregular cross section is computed as a fiber diameter. In addition, when a circular cross section and an irregular cross section are mixed, or when fibers having greatly different fiber diameters are mixed, 100 are selected and calculated so that each has the same number.

(2) Thermosensitive gelation temperature of polyurethane liquid 20 g of polyurethane liquid prepared to a solid content of polyurethane of 20% was added to a test tube having an inner diameter of 12 mm, a thermometer was inserted, the test tube was sealed, and 95 It was immersed in a hot water bath at 0 ° C., and the temperature at which the prepared liquid lost fluidity was measured as the thermal gelation temperature.

(3) Solidification stability of polyurethane liquid After solidifying a test tube having an inner diameter of 12 mm, sealed with 20 g of a polyurethane liquid prepared with a solid content of polyurethane of 20%, immersed in warm water at 95 ° C. for 3 minutes, After returning to room temperature, the fluidity after 10 minutes, 30 minutes and 1 day later was visually confirmed.

(4) Appearance quality The surface quality of the sheet was evaluated by visual inspection and sensory evaluation as follows.
○: Napped length and fiber dispersion state are good.
Δ: Napped length is good, but fiber dispersion is poor. Alternatively, the fibers are dispersed but the napped length is too short.
X: There is almost no napped and it is bad.

(5) Texture Based on A method (45 ° cantilever method) described in JIS L1096: 1999 8.19.1, five test pieces each having a size of 2 × 15 cm are prepared in the vertical direction and the horizontal direction and have a slope of 45 ° C. The sample was placed on a horizontal base, and the test piece was slid to read the scale when the center point of one end of the test piece was in contact with the slope, and the average value of the five pieces was obtained.

[Preparation of polyurethane liquid A]
As a water-based polyurethane resin, a radical reaction is initiated with respect to 100 parts by mass of a solid content of a polyoxyethylene chain-containing polycarbonate-based polyurethane liquid (referred to as “Takelac” XW-76-JE111N “Water-based polyurethane resin 1” manufactured by Mitsui Chemicals Polyurethanes). As an agent, 2 parts by mass of ammonium persulfate was added, and the whole was prepared with water to a solid content of 20% by mass. The thermosensitive gelation temperature of this preparation liquid was 70 ° C. In the evaluation test of the coagulation stability, the fluidity was not recovered even after 10 minutes, 30 minutes, and 1 day after returning to room temperature, and it was good while maintaining the coagulation property.

[Preparation of polyurethane liquid B]
As a water-based polyurethane resin, a radical reaction is initiated with respect to 100 parts by mass of a solid content of a polyoxyethylene chain-containing polyester-based polyurethane liquid (referred to as “Takelac” XW-76-JE201N “Water-based polyurethane resin 2” manufactured by Mitsui Chemicals Polyurethanes). As an agent, 2 parts by mass of ammonium persulfate was added, and the whole was prepared with water to a solid content of 20% by mass. The heat-sensitive gelation temperature of this preparation liquid was 73 ° C. In the evaluation test of the coagulation stability, the fluidity was not recovered even after 10 minutes, 30 minutes, and 1 day after returning to room temperature, and it was good while maintaining the coagulation property.

[Preparation of polyurethane liquid C]
1 part by mass of sodium persulfate was added as a radical reaction initiator to 100 parts by mass of the solid content of the aqueous polyurethane resin 1, and the whole was prepared to a solid content of 20% by mass with water. The thermosensitive gelation temperature of this preparation liquid was 68 ° C. In the evaluation test of the coagulation stability, the fluidity was not recovered even after 10 minutes, 30 minutes, and 1 day after returning to room temperature, and it was good while maintaining the coagulation property.

[Preparation of polyurethane liquid D]
1 part by mass of potassium persulfate was added as a radical reaction initiator to 100 parts by mass of the solid content of the aqueous polyurethane resin 1, and the whole was prepared to a solid content of 20% by mass with water. The thermosensitive gelation temperature of this preparation liquid was 74 ° C. In the evaluation test of the coagulation stability, the fluidity was not recovered even after 10 minutes, 30 minutes, and 1 day after returning to room temperature, and it was good while maintaining the coagulation property.

[Preparation of polyurethane liquid E]
To 100 parts by mass of the solid content of the aqueous polyurethane resin 1, 2 parts by mass of a polyoxyethylene segment-containing azo radical reaction initiator (“VPE-0601” manufactured by Wako Pure Chemical Industries, Ltd.) as a radical reaction initiator is added. The whole was prepared to a solid content of 20% by mass, and this was designated as polyurethane liquid E. The thermosensitive gelation temperature of this preparation liquid was 68 ° C. In the evaluation test of the coagulation stability, the fluidity was not recovered even after 10 minutes, 30 minutes, and 1 day after returning to room temperature, and it was good while maintaining the coagulation property.

[Preparation of polyurethane liquid F]
The solid content of the aqueous polyurethane resin 1 was adjusted to 20% by mass, and this was designated as polyurethane liquid F. The thermosensitive gelation temperature of this preparation liquid was 74 ° C. Further, in the evaluation test of the coagulation stability, when it was returned to room temperature, it was somewhat fluid after 10 minutes, and after 30 minutes, it became liquid and unsatisfactory.

[Preparation of polyurethane liquid G]
To 100 parts by mass of the solid content of the aqueous polyurethane resin 1, 5 parts by mass of sodium sulfate was added as an inorganic salt, and the whole was adjusted to a solid content of 20% by mass with water. The thermosensitive gelation temperature of this preparation liquid was 66 ° C. Further, in the evaluation test of the coagulation stability, after returning to room temperature, there was no fluidity after 10 minutes, but after 30 minutes, fluidity was seen somewhat, and after one day it became liquid and was poor.

[Preparation of polyurethane liquid H]
With respect to 100 parts by mass of the solid content of the aqueous polyurethane resin 1, 5 parts by mass of calcium chloride was added as an inorganic salt, and the whole was prepared to a solid content of 20% by mass with water. The thermosensitive gelation temperature of this preparation liquid was 65 ° C. Further, in the evaluation test of coagulation stability, after returning to room temperature, there was no fluidity after 10 minutes, but after 30 minutes, some fluidity was observed, and after 1 day it became liquid and the coagulation stability was poor. Met.

[Reference example]
20 g of the polyurethane liquid A (containing an aqueous polyurethane resin and ammonium persulfate) and the polyurethane liquid F (only the aqueous polyurethane resin) are put in a test tube having an inner diameter of 12 mm, sealed, and immersed in warm water at 95 ° C. for 3 minutes. After coagulation, the coagulated product and the aqueous layer were separated by centrifugation. As a result of analyzing this water layer portion by LC-MS, from the polyurethane liquid A, the polyoxyethylene chain-derived fragment component of 1.0% by mass with respect to the polyurethane resin content, and from the polyurethane liquid F to the polyurethane resin content. As a result, a fragment derived from 0.3% by mass of polyoxyethylene chains was detected.

[Example 1]
Polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate as the sea component and polyethylene terephthalate as the island component, with a composite ratio of 45% by mass of sea component and 55% by mass of island component, 36 islands / 1 A sea-island type composite fiber having an average fiber diameter of 17 μm was obtained as a filament, cut into a fiber length of 51 mm to form a staple, a web was formed through a card and a cross wrapper, and a nonwoven fabric was formed by needle punching.

  This nonwoven fabric was immersed in 98 ° C. hot water for 2 minutes to shrink and dried at 100 ° C. for 5 minutes. Next, it is impregnated with polyurethane liquid A, treated for 5 minutes in a moist and hot atmosphere at 100 ° C., and then dried with hot air at a drying temperature of 120 ° C. for 5 minutes, so that the polyurethane is 30% by mass with respect to the mass of the island component of the nonwoven fabric. A given sheet was obtained.

Next, this sheet was immersed in an aqueous solution of sodium hydroxide having a concentration of 10 g / L heated to 95 ° C. and treated for 30 minutes to obtain a sea removal sheet from which sea components of sea-island fibers were removed. The average fiber diameter on the sea removal sheet surface was 2 μm. And after raising the surface by grinding using 240 mesh endless sandpaper, the surface was dye | stained with the disperse dye with the circular dyeing machine, and the sheet-like thing was obtained.
The appearance quality and texture of the obtained sheet were good.

[Examples 2 to 5, Comparative Examples 1 to 3]
Except having changed each polyurethane liquid, the process similar to Example 1 was performed and the sheet-like material was obtained.

  The fiber sheet material with polyurethane obtained by the present invention is an interior material having a very elegant appearance as a skin material for furniture, chairs, wall materials, seats, ceilings, interiors, etc. in vehicle interiors of automobiles, trains, aircrafts, etc. , Shirts, jackets, casual shoes, sports shoes, men's shoes, women's shoes, upper and trim of shoes, bags, belts, wallets, etc., clothing materials used for some of them, wiping cloth, abrasive cloth, It can be suitably used as an industrial material such as a CD curtain.

Claims (3)

It comprises applying a polyurethane solution on the fiber base material, water-dispersed polyurethane liquid der which the polyurethane liquid contains a radical reaction initiator is, water-dispersible polyurethane is a nonionic self-emulsifiable polyurethane der Rukoto A method for producing a fibrous sheet with polyurethane, which is characterized. The method for producing a fiber sheet with polyurethane according to claim 1 , wherein the fiber substrate is composed of an ultrafine fiber-expressing fiber or an ultrafine fiber. The method for producing a fiber sheet with polyurethane according to claim 2 , wherein the ultrafine fiber expression type fiber is a sea-island type composite fiber.