JP2013112905A - Sheet-like material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like material that is produced through an environmentally friendly production step, does not leave rucks therein and has soft feeling.SOLUTION: The sheet-like material is obtained by impregnating a nonwoven fabric formed of ultra fine fibers having an average single fiber diameter of 0.3-7 μm with polyurethane. The polyurethane comprises: an aqueous emulsion polyurethane (PU1) which has a heat-sensitive coagulation temperature of 40-90°C and of which the 100% modulus of a dry membrane is 0.1-2 MPa; and an aqueous emulsion polyurethane (PU2) which has a heat-sensitive coagulation temperature of 40-90°C and of which the 100% modulus of a dry membrane is 2.5-5 MPa.

Description

  The present invention relates to an environment-friendly sheet material that does not use an organic solvent in the manufacturing process, and particularly relates to a sheet material that has no wrinkle residue and a good texture.

  A sheet-like material mainly composed of a fibrous base material and polyurethane has excellent characteristics not found in natural leather, and is widely used for various applications. In particular, sheet-like materials using a polyester-based fibrous base material are excellent in light resistance, and therefore their use has been expanded year by year for use in clothing, chair upholstery and automobile interior materials.

  In manufacturing such a sheet-like material, after impregnating a fibrous base material with an organic solvent solution of polyurethane, the obtained fibrous base material is immersed in water or an organic solvent aqueous solution which is a non-solvent of polyurethane. A combination of processes for wet coagulating polyurethane is generally employed. A water-miscible organic solvent such as N, N-dimethylformamide is used as the organic solvent which is a solvent for such 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, a method using a water-emulsion polyurethane in which polyurethane is dispersed in water instead of the conventional organic solvent type polyurethane has been studied. Here, the sheet-like material impregnated with and imparted with water emulsion polyurethane to the fibrous base material has a problem that the texture tends to be hard. There are two main reasons for this: the polyurethane is unevenly distributed in the fibrous base material due to the occurrence of the migration phenomenon, and the polyurethane is firmly gripping the entangled portion of the fiber of the fibrous base material. A solution is being considered.

  As for the migration suppression of the former reason, a technique has been proposed in which an inorganic salt is added as a heat-sensitive coagulant to water-dispersed polyurethane and the fluidity of the water-dispersed polyurethane is lost by heating (see Patent Document 1). However, in the case of this proposal, there is no disclosure about the latter reason, that is, the reason why the polyurethane strongly grips the entangled part of the fiber of the fibrous base material. It will be strongly influenced by the flexibility. For this reason, in order to express a soft texture in a sheet-like material, it is conceivable to apply a flexible polyurethane having low crystallinity. However, in this case, wrinkle recovery is reduced, so that when the sheet is bent, wrinkles remain and cannot be used as a sheet.

  On the other hand, for the suppression of the fiber entanglement point of polyurethane for the latter reason, it is proposed to add an associative thickener to the water emulsion polyurethane to make the polyurethane structure in the fibrous base material porous. (See Patent Document 2). In this proposal, by making the polyurethane porous, the bonding area between the fiber and the polyurethane is reduced, and the gripping force at the entanglement point of the fiber is weakened. However, when an associative thickener is added to a water-emulsion polyurethane, the sheet impregnated with the polyurethane is sticky due to the associative thickener, so a cleaning process for the associative thickener is required. Productivity is low.

  In addition, as a method for suppressing the gripping of fiber entanglement points, a method has been proposed in which a sea-island fiber base material is impregnated with a flexible water-emulsion polyurethane, and after removing sea components, the water-emulsion polyurethane is impregnated again. (See Patent Document 3). In the case of this proposal, by first applying a flexible water-emulsion polyurethane, the tangled point of the fiber is gripped by the flexible polyurethane, and the durability of the product is expressed by the water-emulsion polyurethane that is applied after removing the sea components However, the product is low in productivity because two water emulsion polyurethane impregnation steps are required.

Japanese Patent No. 3166054 JP 2000-297211 A JP 2003-306878 A

  That is, as described above, a sheet-like material having no wrinkle residue and a good texture in the process of not using an organic solvent in the production of the sheet-like material has not been obtained so far.

  Accordingly, an object of the present invention is to provide a sheet-like material having no wrinkle residue and a soft texture by an environment-friendly manufacturing process in view of the background of the above-described prior art.

  The present invention is intended to solve the above problems, and the sheet-like material of the present invention is a sheet-like material containing polyurethane in a non-woven fabric composed of ultrafine fibers having an average single fiber diameter of 0.3 to 7 μm. The polyurethane has a thermal coagulation temperature of 40 to 90 ° C. and a water emulsion polyurethane (PU1) having a dry film 100% modulus of 0.1 to 2 MPa, and a thermal coagulation temperature of 40 to 90 ° C. And a sheet-like product comprising a water-emulsion polyurethane (PU2) having a dry film 100% modulus of 2.5 to 5 MPa.

  According to the preferable aspect of the sheet-like material of the present invention, the mass ratio of PU1 and PU2 of the polyurethane is PU1: PU2 = 1: 9 to 5: 5.

  According to the preferable aspect of the sheet-like material of this invention, the polyurethane content of the said sheet-like material is 1-40 mass% with respect to the mass of the said nonwoven fabric.

  According to the present invention, it has a graceful appearance with suede-like napping by an environmentally friendly manufacturing process, has a good wrinkle recovery property that does not wrinkle when expanded after folding, and is also practical as a garment Can be obtained. In addition, productivity is also good because a plurality of impregnation steps are not required to achieve both good wrinkle recovery and a soft texture.

  The sheet-like material of the present invention is a sheet-like material containing a specific polyurethane in a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.3 to 7 μm. The specific polyurethane includes a water emulsion polyurethane (PU1) having a thermal coagulation temperature of 40 to 90 ° C. and a 100% modulus of the dry film of 0.1 to 2 MPa, and a thermal coagulation temperature of 40 to 90 ° C. It is made of water-emulsion polyurethane (PU2) having a dry film 100% modulus of 2.5 to 5 MPa.

  The nonwoven fabric used in the present invention may be either a short fiber nonwoven fabric or a long fiber nonwoven fabric, but a short fiber nonwoven fabric is preferably used in terms of texture and quality.

  When the fiber length is preferably 25 mm or more, a sheet-like material having excellent wear resistance can be obtained by entanglement. In addition, by making the fiber length preferably 90 mm or less, a sheet-like product having a better texture and quality can be obtained. The fiber length of the short fibers in the short fiber nonwoven fabric is more preferably 30 to 70 mm.

  In the present invention, it is a preferable aspect that the nonwoven fabric has a structure in which fiber bundles (fiber bundles) are intertwined. When the fibers are intertwined in a bundle state, the strength of the sheet-like material is improved. The nonwoven fabric of such an embodiment can be obtained by causing the ultrafine fibers to develop after entanglement of the ultrafine fiber-expressing fibers in advance.

  In the nonwoven fabric, needle punching or water jet punching can be employed as a method for entanglement of fibers or fiber bundles.

  A nonwoven fabric or a knitted fabric can be inserted into the nonwoven fabric for the purpose of improving the strength. The average single fiber diameter of the fibers constituting the woven or knitted fabric is preferably about 0.3 to 10 μm.

  As fibers constituting the nonwoven fabric, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate and polylactic acid, polyamides such as 6-nylon and 66-nylon, acrylic, polyethylene, polypropylene, and thermoplastic cellulose are melted. A fiber made of a thermoplastic resin that can be spun can be used. Among these, polyester fibers are preferably used from the viewpoints of strength, dimensional stability, and light resistance. Moreover, the nonwoven fabric may be configured by mixing fibers of different materials.

  The cross-sectional shape of the fibers constituting the nonwoven fabric may be a round cross section, but may be a polygonal shape such as an ellipse, a flat shape, or a triangle, or a modified cross section such as a sector shape or a cross shape.

  It is important that the average single fiber diameter of the fibers constituting the nonwoven fabric is 0.3 to 7 μm. When the average fiber diameter of the fibers is 7 μm or less, preferably 6 μm or less, more preferably 5 μm or less, the tactile feeling of the nonwoven fabric becomes flexible. On the other hand, by setting the average single fiber diameter of the fibers to 0.3 μm or more, preferably 0.7 μm or more, more preferably 1 μm or more, the dispersion of fibers during napping treatment such as coloring after dyeing or grinding with sandpaper etc. Excellent in ease and judgment.

  Moreover, it is also a preferable aspect to use an ultrafine fiber expression type fiber. By using the ultrafine fiber expression type fiber, it is possible to stably obtain a form in which the above-described fiber bundles are intertwined.

  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 can be preferably used also from the viewpoint of the flexibility and texture of the sheet-like material because an appropriate void can be imparted between the island components, that is, between the ultrafine fibers, by removing the sea components. .

  For the sea-island type fiber, a sea-island type compound base is used, and the sea-island type composite fiber that spins the sea component and the island component by mutual arrangement and the sea component and the island component are mixed and spun. Although there are spun fibers, sea-island type composite fibers are preferably used from the viewpoint that ultrafine fibers having a uniform fineness can be obtained, and that 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, copolymer polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, or the like, polylactic acid, polyvinyl alcohol, or the like can be used. Among them, copolyesters obtained by copolymerizing alkali-decomposable sodium sulfoisophthalate or polyethylene glycol that can be decomposed without using an organic solvent, polylactic acid, and polyvinyl alcohol that can be dissolved and removed with hot water are preferably used. .

  It is important that the average single fiber diameter of the fiber obtained from the island component of the sea-island fiber is 0.3 to 7 μm. By setting the average single fiber diameter 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, when the average single fiber diameter is 0.3 μm or more, preferably 0.7 μm or more, more preferably 1 μm or more, dispersion of bundle fibers during napping treatment such as coloring after dyeing or grinding with sandpaper etc. Excellent in ease and judgment.

  The sea removal treatment when sea-island fibers are used may be performed before or after the polyurethane is applied to the nonwoven fabric. 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 gripped, so that the wear resistance of the sheet-like material 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 texture of the sheet-like material is not directly gripped by the polyurethane. Becomes flexible.

  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, when the sea component is polyethylene, polypropylene, polystyrene, etc., an organic solvent capable of dissolving each sea component polymer such as toluene or trichloroethylene is used. In the case of a polymer that can be dissolved in an alkaline aqueous solution such as lactic acid, an alkaline aqueous solution such as sodium hydroxide can be used, and in the case where the sea component is a water-soluble polymer such as polyvinyl alcohol, hot water can be used.

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

  As the polymer diol, for example, 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. From the viewpoints of light resistance and heat resistance, it is preferable to use a polycarbonate diol and a polyester diol. From the viewpoint of all the balances of hydrolysis resistance, heat resistance and light resistance, polycarbonate diols and polyester diols are more preferable, and polycarbonate diols are particularly preferably used.

  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 alkylene glycols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol. Chain 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, Alicyclic diols such as 1,4-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 types of alkylene glycols may be used.

  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, and One kind or two or more kinds selected from cyclohexane-1,4-dimethanol can be used. Further, addition products obtained by adding various alkylene oxides to bisphenol A can also be used.

  Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro One kind or two or more kinds selected from isophthalic acid can be mentioned.

  Examples of polyether-based diols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymerized diols combining them.

  The number average molecular weight of the polymer diol is preferably 500 to 4000. By making the number average molecular weight of the polymer diol preferably 500 or more, more preferably 1500 or more, it is possible to prevent the texture from becoming hard. Moreover, the intensity | strength as a polyurethane is maintainable by making a number average molecular weight into 4000 or less preferably, more preferably 3000 or less.

  Examples of the organic diisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, and aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, and combinations thereof. May be used. Among these, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate are preferably used from the viewpoint of light resistance.

  As the chain extender, amine chain extenders such as ethylenediamine and methylenebisaniline and diol chain extenders such as ethylene glycol can be used. Moreover, the polyamine obtained by making polyisocyanate and water react can also be used as a chain extender.

  The polyurethane used in the present invention 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 preferable to use an internal cross-linking agent because cross-linking points can be formed more uniformly in the polyurethane molecular structure and the reduction in flexibility can be reduced.

  As the crosslinking agent, compounds having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, and 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 an oxazoline group, a carbodiimide group, and a silanol group are preferable in terms of the balance between reactivity and flexibility. Used.

  In addition, the polyurethane preferably has a hydrophilic group in the molecular structure. By having a hydrophilic group in the molecular structure, the dispersion / stability of the water-dispersed polyurethane can be improved.

  Examples of the hydrophilic group 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 and nonionic hydrophilic groups, and Any hydrophilic group of a combination of anionic and nonionic hydrophilic groups can be employed. Among these, nonionic hydrophilic groups that are free from yellowing caused by light and harmful effects caused by a neutralizing agent are particularly preferable.

  That is, in the case of an anionic hydrophilic group, a neutralizing agent is required. For example, the neutralizing agent is a tertiary amine such as ammonia, triethylamine, triethanolamine, triisopropanolamine, trimethylamine and dimethylethanolamine. In some cases, amines are generated and volatilized by the heat generated during film formation and drying, and released outside the system. For this reason, in order to suppress the release of air and the deterioration of the working environment, it is essential to introduce a device for recovering volatile amines.

  In addition, when the 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. On the other hand, in the case of a nonionic hydrophilic group, since no neutralizing agent is used, it is not necessary to introduce an amine recovery device, and there is no fear of remaining 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. In the case of a nonionic hydrophilic group, since a neutralizing agent is not used, there is no need to worry about deterioration due to hydrolysis of polyurethane.

  It is important that the polyurethane contained in the sheet-like material of the present invention comprises a polyurethane (PU1) having a dry film 100% modulus of 0.1 to 2 MPa and a polyurethane (PU2) of 2.5 to 5 MPa. The polyurethane contained in the sheet-like material is more preferably composed of a polyurethane (PU1) having a 100% modulus of 0.7 to 1.5 MPa and a polyurethane (PU2) of 3 to 4.6 MPa in a dry film. It is. The 100% modulus of the dry film is an index representing the hardness of the polyurethane, and in the sheet-like material containing only PU1 whose 100% modulus is in the former range (0.1 to 2 MPa), the texture is flexible. When wrinkles occur, it becomes difficult to recover. Further, in the sheet-like material containing only PU2 whose 100% modulus is in the latter range (2.5 to 5 MPa), since the PU2 itself is hard, the binding force of the fibers constituting the nonwoven fabric is strong and is not easily wrinkled. However, the texture becomes hard and unusable for practical use.

  The 100% modulus of the dry film can be adjusted by the ratio of the hard segment structure resulting from the isocyanate or chain extender in the polyurethane molecular structure and the type of polyol, isocyanate, and the like.

  In the present invention, when both PU1 and PU2 are used alone, it is not possible to obtain both a soft texture and good wrinkle recovery. However, by using PU1 and PU2 together, a soft texture and good wrinkle can be obtained. It has both recoverability.

  The polyurethane used in the present invention is composed of a mixture of PU1 and PU2, and the mass ratio of PU1 and PU2 is preferably PU1: PU2 = 1: 9 to 5: 5. When the ratio of PU1 is too low, the flexibility of the sheet-like material is lowered, and when the ratio of PU2 is too low, the wrinkle recovery property is lowered. Therefore, the mass ratio is more preferably PU1: PU2 = 2: 8. ~ 4: 6. Said 100% modulus can be adjusted with the ratio of the hard segment structure resulting from the isocyanate and chain extender in a polyurethane molecular structure, and kinds, such as a polyol and isocyanate.

  PU1 and PU2 used in the present invention are water emulsion polyurethanes dispersed and stabilized in water. Water-emulsion polyurethanes are forcibly emulsified polyurethanes that are forcibly dispersed and stabilized using a surfactant, and have a hydrophilic structure in the polyurethane molecular structure, and are dispersed in water without the presence of a surfactant. -It is classified as a self-emulsifying polyurethane that stabilizes. Any of these may be used in the present invention.

  The concentration of the water emulsion polyurethane (content of polyurethane relative to the water emulsion polyurethane liquid) is preferably 5% by mass to 50% by mass, more preferably 8%, from the viewpoint of the storage stability of the water emulsion polyurethane liquid. It is 40 mass%.

  In the present invention, the polyurethane liquid is applied to the nonwoven fabric which is a fibrous base material and then solidified to give polyurethane to the nonwoven fabric. However, it is preferable to apply polyurethane uniformly in the thickness direction of the nonwoven fabric. The liquid preferably exhibits heat-sensitive coagulation. When the heat-sensitive coagulation property is not exhibited, the polyurethane liquid undergoes a migration phenomenon that concentrates on the surface layer of the nonwoven fabric during dry coagulation, and the texture of the polyurethane sheet tends to be cured. The heat-sensitive coagulation property refers to a property that, when a polyurethane liquid is heated, the fluidity of the polyurethane liquid decreases and solidifies when reaching a certain temperature (heat-sensitive coagulation temperature).

  In the present invention, the heat-sensitive coagulation temperature of polyurethane is preferably 40 ° C to 90 ° C for both PU1 and PU2. By setting the heat-sensitive coagulation 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 nonwoven fabric can be suppressed by making thermosensitive coagulation temperature into 90 degrees C or less. The heat-sensitive coagulation temperature is more preferably 50 ° C to 80 ° C. When either PU1 or PU2 does not have a thermal coagulation temperature, only polyurethane that does not have a thermal coagulation temperature migrates. Therefore, in the present invention, both PU1 and PU2 need to have a thermal coagulation temperature. In addition, when the heat-sensitive coagulation temperatures of PU1 and PU2 differ by 5 ° C or more, more preferably by 10 ° C or more, phase separation of PU1 and PU2 during heat-sensitive coagulation occurs clearly, and both flexibility and wrinkle recovery are achieved. Cheap.

  In order to make the heat-sensitive coagulation temperature within the range as described above (40 ° C. to 90 ° C.), a heat-sensitive coagulant can be appropriately added. Examples of the thermal coagulant include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate and calcium chloride, and radicals such as sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, and benzoyl peroxide. A reaction initiator is mentioned.

  The water emulsion polyurethane liquid used in the present invention includes various additives such as pigments such as carbon black, flame retardants such as phosphorus, halogen, silicone and inorganic, phenol, sulfur and phosphorus. Antioxidants, benzotriazoles, benzophenones, salicylates, cyanoacrylates, oxalic acid anilides and other UV absorbers, hindered amines, benzoates, and other light stabilizers, polycarbodiimides, etc. Agents, plasticizers, antistatic agents, surfactants, softeners, water repellents, coagulation regulators, dyes, preservatives, antibacterial agents, deodorants, fillers such as cellulose particles, and silica and titanium oxide It may contain inorganic particles.

  The water-emulsion 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 properties. Therefore, the content of the organic solvent is preferably 1% by mass or less.

  A water emulsion polyurethane liquid can be impregnated into a nonwoven fabric, coated, etc., and the polyurethane can be coagulated by dry heat coagulation, wet heat coagulation, wet coagulation, or a combination thereof.

  The wet heat coagulation temperature may be not less than the heat sensitive coagulation temperature of polyurethane, and is preferably 40 ° C. to 200 ° C., for example. By setting the wet heat solidification temperature to preferably 40 ° C. or higher, more preferably 80 ° C. or higher, the time to solidification of the polyurethane can be shortened to further suppress the migration phenomenon. On the other hand, the heat deterioration of the polyurethane can be prevented by setting the wet heat coagulation temperature to preferably 200 ° C. or lower, more preferably 160 ° C. or lower.

  Moreover, the temperature of wet coagulation should just be more than the heat-sensitive coagulation temperature of a polyurethane, for example, it is preferable that it is 40 to 100 degreeC. By setting the temperature of wet coagulation in hot water to 40 ° C. or higher, more preferably 80 ° C. or higher, the time to solidification of polyurethane can be shortened to further suppress the migration phenomenon.

  The dry solidification temperature and the drying temperature are preferably 80 ° C to 160 ° C. Productivity is excellent when the dry coagulation temperature and the drying temperature are preferably 80 ° C. or higher, more preferably 90 ° C. or higher. On the other hand, when the dry coagulation temperature and the drying temperature are preferably 180 ° C. or lower, more preferably 160 ° C. or lower, thermal deterioration of the polyurethane can be prevented.

  It is preferable that content of the polyurethane with respect to the sheet-like material obtained by this invention is 1-40 mass% with respect to the nonwoven fabric mass. By setting the content ratio of the polyurethane to preferably 1% by mass or more, more preferably 3% by mass or more, it is possible to obtain sheet strength and to prevent the fibers from falling off. Moreover, by making the content ratio of polyurethane preferably 40% by mass or less, more preferably 35% by mass or less, it is possible to prevent the texture from becoming hard and to obtain good napped quality.

  After polyurethane is applied to the nonwoven fabric, dividing the polyurethane-applied sheet-like material into half or several sheets in the sheet thickness direction is a preferable aspect with excellent production efficiency.

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

  In order to form napping on the surface of the sheet-like material, napping treatment can be performed. The raising treatment can be performed by a method of grinding using sandpaper, roll sander or the like.

  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. In general, the dyeing temperature is preferably from 80 ° C to 150 ° C, more preferably from 110 ° C to 130 ° C.

  The dye can be selected according to the type of fiber constituting the nonwoven fabric. For example, disperse dyes can be used for polyester fibers, acidic dyes or metal-containing dyes can be used for polyamide fibers, and combinations thereof can be used. When dyed with disperse dyes, reduction washing may be performed after dyeing.

  It is also a preferred embodiment to use a dyeing assistant during dyeing. By using a dyeing assistant, the uniformity and reproducibility of dyeing can be improved. In addition, a finishing treatment using a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, a light proofing agent, and an antibacterial agent can be performed in the same bath or after dyeing.

  The sheet-like material obtained by the present invention includes furniture, chairs and wall materials, interior materials having a very elegant appearance as a skin material such as seats, ceilings and interiors in vehicle interiors such as automobiles, trains and aircraft, shirts, Jackets, casual shoes, sports shoes, uppers and trims for shoes such as men's shoes and women's shoes, bags, belts, wallets, etc., clothing materials used for some of them, wiping cloth, polishing cloth, CD curtains, etc. It can be suitably used as an industrial material.

  Hereinafter, although the sheet-like material of the present invention and the manufacturing method thereof will be described more specifically with reference to examples, the present invention is not limited to only these examples. The evaluation methods in the examples are as follows.

[Evaluation method]
(1) Average single fiber diameter The average single fiber diameter was obtained by taking a scanning electron microscope (SEM) photograph of the surface of the nonwoven fabric or sheet-like material at a magnification of 2000 times, and randomly forming 100 circular or nearly elliptical fibers. This was calculated by measuring the single fiber diameter and calculating the average value.

  When the ultrafine fiber constituting the nonwoven fabric or the sheet-like material has an irregular cross section, the outer peripheral circular diameter of the irregular cross section is calculated as the single 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) 100% modulus of polyurethane dry film 20% by weight water emulsion polyurethane solution is placed in a 5cm x 10cm x 1cm polyethylene tray, air-dried at 25 ° C for 8 hours, and then hot-air dryer at 120 ° C for 2 hours. Heat treatment was performed to obtain a polyurethane dry film having a thickness of 1 mm. With respect to this polyurethane dry film, the tensile strength at 100% elongation was measured as 100% modulus in accordance with Method A (strip method) described in the tensile tester JIS-L1096-8.12.1 (1999).

(3) Thermosensitive coagulation temperature of water emulsion polyurethane liquid 20 g of water emulsion polyurethane liquid prepared with a solid content of polyurethane of 10% by mass was added to a test tube having an inner diameter of 12 mm, a thermometer was inserted, and then the test tube Was immersed in a warm water bath at a temperature of 95 ° C., and the temperature at which the prepared liquid lost fluidity was measured as the thermal coagulation temperature.

(4) Texture Based on A method (45 ° cantilever method) described in JIS L1096-8.19.1 (1999), 5 test pieces each having a size of 2 × 15 cm in the vertical direction and the horizontal direction were prepared. The sample was placed on a horizontal platform having a temperature slope, 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.

(5) Wrinkle recovery property Based on the Monsanto method described in JIS L1059-1 (1998), the wrinkle recovery angle of 5 test pieces was measured using a 10N load device. formula,
-Anti-wrinkle rate (%) = α x 100 ÷ 180 (α = wrinkle recovery angle (°))
Was used to calculate wrinkle recovery and the average value of 5 sheets was obtained.

(6) Appearance quality The appearance quality of the sheet-like material was the highest, with 10 healthy adult men and 10 adult women each, with a total of 20 evaluators. Evaluation was defined as appearance quality. Appearance quality is good for grades 3 to 5, and grades 4 and 5 are acceptable.
Grade 5: Uniform fiber napping, good fiber dispersion, good appearance and natural leather.
Grade 4: Evaluation between grade 5 and grade 3.
Third grade: The dispersion state of the fibers is slightly poor, but there is fiber napping, the appearance is reasonably good, and the appearance of artificial leather.
Second grade: An evaluation between the third grade and the first grade.
First grade: There are few raised fibers, and the overall dispersion state of the fibers is very poor, and the appearance is poor.

  Adjustment of the polyurethane liquid used in the examples is as follows.

[Preparation of polyurethane liquid A]
As a water-emulsion-based polyurethane resin, a polycarbonate-based forced emulsification type polyurethane liquid containing a carboxylic acid triethylamine salt, in which a polycarbonate polycarbonate diol of polyhexamethylene carbonate and 3-methylpentane carbonate is applied to a polyol and isophorone diisocyanate is applied to an isocyanate 15 parts by mass of sodium sulfate was added as a heat-sensitive coagulant to 100 parts by mass of the solid content, and the whole was prepared to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid B]
As a water-emulsion-based polyurethane resin, a polycarbonate-based forced emulsification type polyurethane liquid containing a carboxylic acid triethylamine salt, in which a polycarbonate polycarbonate diol of polyhexamethylene carbonate and 3-methylpentane carbonate is applied to a polyol and isophorone diisocyanate is applied to an isocyanate As a heat-sensitive coagulant, 20 parts by mass of sodium sulfate was added to 100 parts by mass of the solid content, and the whole was prepared to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid C]
As water-emulsion polyurethane resin, heat-sensitive to 100 parts by mass of solid content of carboxylic acid triethylamine salt-containing polyether-based compulsory emulsification type polyurethane liquid in which polytetramethylene glycol is applied to polyol and dicyclohexylmethane diisocyanate is applied to isocyanate. As a coagulant, 5 parts by mass of sodium sulfate was added, and the whole was adjusted to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid D]
As a water emulsion polyurethane resin, the polyurethane liquid used in the polyurethane liquid A was prepared by adding water to a solid content of 10% by mass without adding a heat-sensitive coagulant.

[Preparation of polyurethane liquid E]
As water emulsion polyurethane resin, heat-sensitive to 100 parts by mass of solid content of carboxylic acid triethylamine salt-containing polyether-based forced emulsification type polyurethane liquid in which polytetramethylene glycol is applied to polyol and hexamethylene diisocyanate is applied to isocyanate. As a coagulant, 5 parts by mass of sodium sulfate was added, and the whole was prepared with water to a solid content of 10% by mass.

[Preparation of polyurethane liquid F]
As water-emulsion polyurethane resin, heat-sensitive coagulation with respect to 100 parts by mass of polyoxyethylene chain-containing polycarbonate self-emulsifying polyurethane liquid in which polyhexamethylene carbonate is applied to polyol and dicyclohexylmethane diisocyanate is applied to isocyanate 2 parts by mass of ammonium persulfate was added as an agent, and the whole was adjusted to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid G]
Polycarbonate containing carboxylic acid triethylamine with a composition in which polyhexamethylene carbonate is applied to the polyol and dicyclohexylmethane diisocyanate is applied to the isocyanate, and the hard segment amount is increased as compared with the polyurethane used in the polyurethane liquid F, as the water emulsion polyurethane resin. To 100 parts by mass of the solid content of the system forced emulsification type polyurethane liquid, 10 parts by mass of sodium sulfate was added as a heat-sensitive coagulant, and the whole was adjusted to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid H]
As a water-emulsion-based polyurethane resin, a polycarbonate-based triethylamine salt-containing polycarbonate system in which hexamethylene carbonate is applied to the polyol and dicyclohexylmethane diisocyanate is applied to the isocyanate, and the hard segment amount is increased as compared with the polyurethane used in the polyurethane liquid G To 100 parts by mass of the solid content of the forced emulsification type polyurethane liquid, 18 parts by mass of sodium sulfate was added as a heat-sensitive coagulant, and the whole was adjusted to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid I]
As a water-emulsion polyurethane resin, heat-sensitive coagulant for 100 parts by mass of the solid content of a polycarbonate-based forced emulsification type polyurethane liquid containing triethylamine salt of carboxylic acid, in which hexamethylene carbonate is applied to polyol and isophorone diisocyanate is applied to isocyanate. As a result, 5 parts by mass of sodium sulfate was added, and the whole was adjusted to a solid content of 10% by mass with water.

[Preparation of polyurethane liquid J]
As water-emulsion polyurethane resin, heat-sensitive coagulation with respect to 100 parts by mass of the solid content of the polyether-based forced emulsification type polyurethane liquid containing triethylamine salt of carboxylic acid, in which hexamethylene carbonate is applied to polyol and dicyclohexylmethane diisocyanate is applied to isocyanate. 5 parts by weight of sodium sulfate was added as an agent, and the whole was adjusted to a solid content of 10% by weight with water.

  Table 1 shows the compositions and properties of the polyurethane liquids A to J adjusted as described above.

[Example 1]
As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is used, and as the island component, polyethylene terephthalate is used. The sea component is 45% by mass and the island component is 55% by mass. / 1 filament, sea island type composite fiber having an average single fiber diameter of 17 μm was obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber 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 hot water at a temperature of 98 ° C. for 2 minutes to shrink and dried at a temperature of 100 ° C. for 5 minutes. Next, the polyurethane liquid A adjusted as above as PU1 and the polyurethane liquid F adjusted as above as PU2 are mixed into this nonwoven fabric so that the mass ratio of polyurethane (A and F) is A: F = 3: 7. Impregnated with the water emulsion polyurethane solution, treated in a moist and hot atmosphere at a temperature of 100 ° C. for 5 minutes, and then dried with hot air at a drying temperature of 120 ° C. for 5 minutes, so that the polyurethane mass relative to the island component mass of the nonwoven fabric is 30 mass. %, A sheet provided with polyurethane was obtained.

  Next, the sheet thus obtained was immersed in a 10 g / L sodium hydroxide aqueous solution heated to a temperature of 95 ° C. and treated for 30 minutes to remove sea components from the sea-island fibers. A sheet was obtained. The average monofilament diameter on the surface of the obtained sea removal sheet was 2 μm. The surface of the seawater-removed sheet was brushed by grinding using a 240 mesh endless sandpaper, then dyed with disperse dye using a circular dyeing machine, and subjected to reduction cleaning to obtain a sheet. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 2]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (C and G) was C: G = 2: 8. In the same manner as in Example 1, a sheet was obtained. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 3]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (A and G) was A: G = 4: 6. In the same manner as in Example 1, a sheet was obtained. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 4]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (B and F) was B: F = 4: 6. In the same manner as in Example 1, a sheet was obtained. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 5]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (A and J) was A: J = 3: 7. In the same manner as in Example 1, a sheet was obtained. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 6]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (E and I) was E: I = 3: 7. In the same manner as in Example 1, a sheet was obtained. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 7]
As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is used, and as the island component, polyethylene terephthalate is used. / 1 filament, sea island type composite fiber having an average single fiber diameter of 20 μm was obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber 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 hot water at a temperature of 98 ° C. for 2 minutes to shrink and dried at a temperature of 100 ° C. for 5 minutes. Next, the polyurethane liquid A adjusted as above as PU1 and the polyurethane liquid F adjusted as above as PU2 are mixed into this nonwoven fabric so that the mass ratio of polyurethane (A and F) is A: F = 3: 7. Impregnated with the water emulsion polyurethane solution, treated in a moist and hot atmosphere at a temperature of 100 ° C. for 5 minutes, and then dried with hot air at a drying temperature of 120 ° C. for 5 minutes, so that the polyurethane mass relative to the island component mass of the nonwoven fabric is 30 mass. %, A sheet provided with polyurethane was obtained.

  Next, the sheet thus obtained was immersed in a 10 g / L sodium hydroxide aqueous solution heated to a temperature of 95 ° C. and treated for 30 minutes to remove sea components from the sea-island fibers. A sheet was obtained. The average single fiber diameter on the surface of the obtained sea-sealing sheet was 4.6 μm. The surface of the seawater-removed sheet was brushed by grinding using a 240 mesh endless sandpaper, then dyed with disperse dye using a circular dyeing machine, and subjected to reduction cleaning to obtain a sheet. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Example 8]
As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is used, and as the island component, polyethylene terephthalate is used. / 1 filament, sea island type composite fiber having an average single fiber diameter of 17 μm was obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber 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 hot water at a temperature of 98 ° C. for 2 minutes to shrink and dried at a temperature of 100 ° C. for 5 minutes. Next, the polyurethane liquid A adjusted as above as PU1 and the polyurethane liquid F adjusted as above as PU2 are mixed into this nonwoven fabric so that the mass ratio of polyurethane (A and F) is A: F = 3: 7. Impregnated with the water emulsion polyurethane solution, treated in a moist and hot atmosphere at a temperature of 100 ° C. for 5 minutes, and then dried with hot air at a drying temperature of 120 ° C. for 5 minutes, so that the polyurethane mass relative to the island component mass of the nonwoven fabric is 30 mass. %, A sheet provided with polyurethane was obtained.

  Next, the sheet thus obtained was immersed in a 10 g / L sodium hydroxide aqueous solution heated to a temperature of 95 ° C. and treated for 30 minutes to remove sea components from the sea-island fibers. A sheet was obtained. The average single fiber diameter on the surface of the obtained sea removal sheet was 0.4 μm. The surface of the seawater-removed sheet was brushed by grinding using a 240 mesh endless sandpaper, then dyed with disperse dye using a circular dyeing machine, and subjected to reduction cleaning to obtain a sheet. The obtained sheet-like product had good appearance quality, texture and wrinkle recovery rate.

[Comparative Example 1]
In Example 1, except that the polyurethane liquid was changed as shown in Table 2 and impregnated with a water emulsion polyurethane liquid mixed so that the mass ratio of polyurethane (A and H) was A: H = 5: 5. In the same manner as in Example 1, a sheet was obtained. Although the wrinkle recovery rate of the obtained sheet-like material was good, the texture became hard.

[Comparative Example 2]
In Example 1, a sheet-like material was obtained in the same manner as in Example 1 except that the polyurethane liquid was changed as shown in Table 2. The texture of the obtained sheet was good, but the wrinkle recovery rate was poor.

[Comparative Example 3]
In Example 1, a sheet-like material was obtained in the same manner as in Example 1 except that the polyurethane liquid was changed as shown in Table 2. The obtained sheet-like product had a good wrinkle recovery rate, but the texture became hard and the appearance quality was poor.

[Comparative Example 4]
In Example 1, a sheet-like material was obtained in the same manner as in Example 1 except that the polyurethane liquid was changed as shown in Table 2. The obtained sheet-like product had a good wrinkle recovery rate, but the texture became hard and the appearance quality was poor.

  Table 2 shows the evaluation results of the sheet-like materials obtained in the above Examples and Comparative Examples.

Claims (3)

  A sheet-like material in which polyurethane is contained in a nonwoven fabric composed of ultrafine fibers having an average single fiber diameter of 0.3 to 7 μm, and the polyurethane has a thermal coagulation temperature of 40 to 90 ° C. and 100% modulus of a dry film. Emulsion polyurethane (PU1) having a 0.1 to 2 MPa, and a water emulsion polyurethane (PU2) having a thermal coagulation temperature of 40 to 90 ° C. and a 100% modulus of the dry film of 2.5 to 5 MPa. A sheet-like material comprising:   The sheet-like material according to claim 1, wherein a mass ratio of PU1 and PU2 of polyurethane is PU1: PU2 = 1: 9 to 5: 5.   The sheet-like material according to claim 1 or 2, wherein the polyurethane content of the sheet-like material is 1 to 40% by mass relative to the mass of the nonwoven fabric.