CN104838063B - Tablet and the manufacture method of this tablet - Google Patents

Abstract

The present invention provides the aesthetic look and soft feel that the manufacture method of a kind of tablet, described tablet be capable of having pile, and has better mar proof.The manufacture method of the tablet of the present invention is characterised by, carries out following operation 1～5 successively.Operation (1): the polyvinyl alcohol that to make saponification degree be more than 98%, the degree of polymerization is 800～3500 is dissolved in water, obtains methyl acetate, acetic acid, methanol are respectively the polyvinyl alcohol water solution of below 50ppm；Operation (2): be this polyvinyl alcohol of 0.1～50 mass % for manifesting the fibrous substrate that fiber type is main composition composition with superfine fibre and giving relative to the fiber quality of this fibrous substrate；Operation (3): the fibrous substrate obtained from above-mentioned operation (2) shows the superfine fibre of average single fiber a diameter of 0.3～7 μm；Operation (4): give water dispersant type polyaminoester to the fibrous substrate obtained in above-mentioned operation (3)；Operation (5): remove polyvinyl alcohol in the fibrous substrate obtained from above-mentioned operation (4).

Description

Sheet and method for manufacturing same

technical field

The present invention relates to a sheet-shaped object and a method for producing the sheet-shaped object. The sheet-shaped object uses water-dispersible polyurethane as a binder resin to reduce the amount of organic solvent used in the manufacturing process, and the sheet-shaped object is environmentally friendly. In terms of materials, it can achieve good softness and superior appearance quality at the same time, and has good wear resistance.

Background technique

A sheet mainly composed of a fibrous base material and polyurethane has excellent characteristics not found in natural leather, and is widely used in various applications. In particular, since leather-like sheets using polyester-based fiber substrates are excellent in light resistance, their use in clothing, seat surface processing materials, and automotive interior materials is increasing every year. .

When producing the above-mentioned sheet, the following steps are generally adopted: After impregnating the fibrous base material with an organic solvent solution of polyurethane, the obtained fibrous base material is immersed in water or a mixture of organic solvent/water as a non-solvent of polyurethane. solution for wet coagulation of polyurethane. As an organic solvent that is a solvent for the polyurethane, a water-miscible organic solvent such as N,N-dimethylformamide (hereinafter also referred to as "DMF") is used. For example, the following method has been proposed: impregnating a nonwoven fabric with Polyvinyl alcohol (hereinafter also referred to as "PVA") aqueous solution to obtain a fiber sheet, immerse the fiber sheet in the polyurethane impregnation solution, and then wet-cure the polyurethane in a 45% DMF aqueous solution at 20°C , DMF and polyvinyl alcohol were removed with hot water at 85° C. to produce a sheet (see Patent Document 1). However, since organic solvents are generally highly harmful to the human body and the environment, there is a strong demand for a method that does not use organic solvents when producing sheets.

As a specific solution to this, for example, a method of using a water-dispersible polyurethane obtained by dispersing polyurethane in water instead of the conventional organic solvent-type polyurethane has been studied. However, there is a problem that the handfeel of the sheet-like product formed by impregnating and imparting water-dispersible polyurethane to the fibrous base material becomes hard. The main reason for this problem is that polyurethane bonds strongly to the fibers of the fibrous substrate. In order to solve the above-mentioned problems, researches have been carried out, and the following method has been proposed: in order to partially suppress the adhesion of fibers and polyurethane and to create voids between fibers and polyurethane, similarly to the production process of conventional organic solvent-based polyurethanes, A method in which PVA is previously applied to a fibrous base material, polyurethane is applied thereafter, and PVA is subsequently removed (see Patent Document 2).

Here, since PVA is water-soluble, when water is applied to the fibrous base material after PVA is applied, PVA will dissolve and fall off. In 2, the following methods were used in (i) the ultra-fine fiber step using an alkaline aqueous solution and (ii) the impregnation step of water-dispersed polyurethane. That is, adding borax to the alkaline aqueous solution suppressed the former, that is, the shedding of fibers in the process of ultra-fine fiber, while on the other hand, for the latter, that is, the impregnation process of water-dispersed polyurethane, by using a saponification degree of 98%. And the PVA with a degree of polymerization of 500 inhibits the shedding of PVA to water. However, regarding the effect of adding borax in the process of ultra-fine fiber, since the immersion time in the alkaline aqueous solution takes a long time when the fiber is ultra-fine, even if borax is added to the alkaline aqueous solution, it cannot be completely improved. Inhibit the dissolution of PVA into water. In addition, regarding the impregnation process of water-dispersed polyurethane, due to the low degree of polymerization of PVA, its dissolution into water cannot be completely suppressed, and the shedding of water-dispersed polyurethane liquid cannot be suppressed, so PVA dissolves in the water-dispersed polyurethane liquid. , resulting in the inability to stably control the bonded state of the polyurethane and the fiber, resulting in the problem that the feel of the sheet becomes hard.

In addition, in view of the problems in the above (i) (ii) steps, the following method has been proposed: PVA with a saponification degree of 90% or more is provided to a nonwoven fabric sheet, and heating is performed at 150 to 195° C., thereby reducing A method for the solubility of PVA in water (see Patent Document 3). Although the intermolecular hydrogen bonds of PVA are strengthened by heating at high temperature, thereby reducing the solubility to water, but if the temperature is too high or the heating time is too long, PVA will be insoluble and redissolution in water will become difficult. Therefore, there is a problem that stabilization under appropriate conditions is difficult.

Patent Document 1: Japanese Patent Laid-Open No. 2002-30579

Patent Document 2: Japanese Patent Laid-Open No. 2003-096676

Patent Document 3: Japanese Patent No. 4644971

Contents of the invention

The invention provides a method for manufacturing a sheet and the sheet obtained by the above-mentioned manufacturing method. The manufacturing method can reduce the use of organic solvents in the manufacturing process and is environmentally friendly. The sheet can simultaneously realize The pile has a beautiful appearance and soft feel, and has good wear resistance.

That is, the manufacturing method of the sheet-like article of the present invention is characterized in that the following steps 1 to 5 are sequentially performed,

Step 1: dissolving polyvinyl alcohol with a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water to obtain an aqueous solution of polyvinyl alcohol with concentrations of methyl acetate, acetic acid and methanol below 50 ppm respectively;

Step 2: Applying the polyvinyl alcohol aqueous solution to the fibrous base material mainly composed of microfiber-developing fibers, thereby imparting 0.1 to 50% by mass of the polyethylene to the fiber mass contained in the fibrous base material. alcohol;

Step 3: developing ultrafine fibers with an average single fiber diameter of 0.3 to 7 μm from a fibrous base material mainly composed of ultrafine fiber-displaying fibers;

Step 4: imparting water-dispersible polyurethane to the fibrous base material mainly composed of microfibers to which the polyvinyl alcohol has been imparted;

Step 5: Removing polyvinyl alcohol from the fibrous base material mainly composed of microfibers to which the water-dispersible polyurethane is applied.

A preferable aspect of the manufacturing method of the sheet-shaped article of the present invention is a step of obtaining an aqueous polyvinyl alcohol solution having a concentration of 0.1 to 50 ppm of methyl acetate, acetic acid, and methanol, respectively.

According to a preferred aspect of the method for producing a sheet-shaped article of the present invention, the step of developing ultrafine fibers is a step of treating with an aqueous alkaline solution.

A preferable aspect of the manufacturing method of the sheet-shaped object of this invention includes the process of providing the said polyvinyl alcohol, and heating at 80-170 degreeC.

According to a preferred mode of the manufacturing method of the sheet-shaped object of the present invention, the fibrous base material mainly composed of microfiber display fibers is entangled and integrated with the fabric and/or braided fabric.

In addition, the density of the obtained sheet is preferably 0.2 to 0.7 g/cm ³ .

According to the present invention, it is possible to obtain a sheet-shaped article having a beautiful appearance and a soft texture (which cannot be achieved at the same time conventionally) and having better abrasion resistance despite an environmentally friendly manufacturing process.

detailed description

The manufacturing method of the sheet-shaped article of the present invention is characterized in that the following steps 1 to 5 are carried out sequentially,

Step 1: dissolving polyvinyl alcohol with a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water to obtain an aqueous solution of polyvinyl alcohol with concentrations of methyl acetate, acetic acid and methanol below 50 ppm respectively;

Step 2: Applying the above-mentioned polyvinyl alcohol aqueous solution to the fibrous base material mainly composed of ultrafine fiber-developing fibers, thereby providing 0.1 to 50% by mass of the above-mentioned polyethylene with respect to the fiber mass contained in the fibrous base material. alcohol;

Step 3: developing ultrafine fibers with an average single fiber diameter of 0.3 to 7 μm from a fibrous base material mainly composed of ultrafine fiber-displaying fibers;

Step 4: imparting water-dispersible polyurethane to the fibrous base material mainly composed of microfibers to which the polyvinyl alcohol has been imparted;

Step 5: Removing polyvinyl alcohol from the fibrous base material mainly composed of microfibers to which the water-dispersible polyurethane is applied.

It is important to perform steps 1 to 5 sequentially in the method for producing a sheet-shaped article of the present invention. After applying an aqueous solution of polyvinyl alcohol (also denoted as PVA) with a degree of saponification of 98% or more and a degree of polymerization of 800 to 3,500 to a fibrous substrate mainly composed of microfiber-displaying fibers, the microfibers are displayed. The process in which microfibers are developed from microfibers (sea removal process), and then water-dispersed polyurethane liquid is applied to the fibrous base material with PVA as the main component of ultrafine fibers, and then removed from the fibrous base material. PVA, whereby large voids originating from PVA and sea components are generated between fibers and polyurethane, and since polyurethane partially directly holds microfibers, it is possible to exhibit a beautiful appearance and soft feel, as well as good abrasion resistance physical properties such as sex.

In addition, when the PVA aqueous solution is applied to the fibrous substrate and heated and dried, the PVA in the water undergoes a so-called migration phenomenon (that is, it is concentrated and adhered to the surface layer of the fibrous substrate driven by the movement of water), and a large amount of it is deposited on the surface of the fibrous substrate. The surface layer of the fibrous substrate and a small amount of it adhere to the inner layer. By migrating the PVA, the water-dispersible polyurethane to be given later is mainly attached to the inner layer of the fibrous base material. Then, when the PVA is removed, near the surface layer of the fibrous base material to which a large amount of PVA is attached, large gaps are generated between the fibers and the polyurethane, and the surface appearance of the sheet through the napping process becomes a beautiful appearance (pile). Uniform fiber opening without bundling).

On the other hand, if the desea treatment is performed after removing PVA, both the voids caused by the removal of PVA and the voids caused by the deseared sea components will be generated between the polyurethane and the microfibers. The area where polyurethane directly holds microfibers is further reduced, and the feel of the sheet becomes softer, but physical properties such as abrasion resistance tend to deteriorate.

[1st process]

First, the first step will be described, that is, the step of dissolving PVA with a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water to obtain an aqueous PVA solution having a concentration of methyl acetate, acetic acid, and methanol of 50 ppm or less.

Methyl acetate, acetic acid, and methanol are substances produced during the process of increasing the degree of saponification from polyvinyl acetate, the precursor of PVA synthesis, and can also be produced by the decomposition of residual polyvinyl acetate that has not been fully saponified substance. Regarding methyl acetate, acetic acid, and methanol, by making the concentration of methyl acetate, acetic acid, and methanol in the PVA aqueous solution to be 50 ppm or less respectively, it is easy to form PVA intermolecular hydrogen bonds during heating and drying, and it is possible to inhibit the release of PVA to water (including Solubility in warm water), acid, and alkaline aqueous solutions. In addition, since the intermolecular hydrogen bonds of PVA are easily formed, the heating and drying temperature can be set to a relatively low temperature (80 to 140° C.), thereby suppressing thermal decomposition of PVA. The concentrations of methyl acetate, acetic acid, and methanol in the PVA aqueous solution are more preferably 0.1 to 50 ppm respectively. By making methyl acetate, acetic acid, and methanol exist in small amounts, they are weakly hydrogen-bonded with PVA molecules, so that the PVA molecules The smaller the distance, the easier the formation of hydrogen bonds between PVA molecules. If the concentrations of methyl acetate, acetic acid, and methanol are too high, the formation of hydrogen bonds between PVA molecules will be inhibited. Therefore, the more preferable concentration is 0.3-40 ppm, and the more preferable concentration is 5-40 ppm.

In addition, the concentrations of methyl acetate, acetic acid, and methanol in the PVA aqueous solution were analyzed as follows. 1 g of PVA aqueous solution was charged into a 24 mL heating tube, and heated at 90° C. for 1 hour. 0.1 mL of generated gas was collected from the heating tube with a gas-tight syringe, introduced into GC/MS (mass spectrometer directly connected to a gas chromatograph) and analyzed.

In order to reduce the concentration of methyl acetate, acetic acid, and methanol in the PVA aqueous solution, it is possible to use PVA that generates less methyl acetate, acetic acid, and methanol when the PVA itself is heated before making the aqueous solution, or in the preparation of the PVA aqueous solution. , prolong the heating time when the temperature is raised (which is used to dissolve PVA in water). For the former, the higher the degree of saponification, the less the amount of methyl acetate, acetic acid, and methanol produced, so it is preferable to use PVA with a high degree of saponification of 98% or more. In addition, for the latter, if the heating temperature is too low, methyl acetate, acetic acid, and methanol cannot be sufficiently removed, so it is preferably 80 to 100° C. If the heating time is too short, methyl acetate, acetic acid cannot be sufficiently removed. , Methanol, so it is preferably more than 1 hour. It should be noted that methyl acetate, acetic acid, and methanol may be completely removed from the PVA aqueous solution.

In embodiment of this invention, the saponification degree of the PVA provided to a fibrous base material is 98% or more, and the polymerization degree is 800-3500. When the degree of saponification of PVA is 98% or more, it is possible to prevent PVA from being dissolved in the water-dispersible polyurethane liquid when the water-dispersible polyurethane is imparted. If PVA is dissolved in the water-dispersed polyurethane liquid, not only the effect of protecting the surface of the microfibers constituting the pile cannot be sufficiently obtained, but also when the water-dispersed polyurethane liquid dissolved with PVA is given to the fibrous substrate, PVA is absorbed into polyurethane, and it becomes difficult to remove PVA afterwards, so that the bonded state of polyurethane and fiber cannot be controlled stably, and the texture becomes hard.

In addition, the solubility of PVA in water changes depending on the degree of polymerization, and the smaller the degree of polymerization of PVA is, the more the PVA dissolves in the water-dispersible polyurethane liquid when it is imparted to the water-dispersible polyurethane. The higher the degree of polymerization of PVA, the higher the viscosity of the PVA aqueous solution. When the fibrous substrate is impregnated with the PVA aqueous solution, PVA cannot penetrate into the inside of the fibrous substrate. Therefore, the degree of polymerization of PVA is preferably 1000 to 3000, more preferably 1200~2500.

In the present invention, for PVA, the viscosity at 20° C. of a 4% by mass aqueous solution is preferably 10 to 70 mPa·s. When the viscosity of PVA is within the above range, an appropriate migration structure can be obtained inside the fibrous substrate during drying, and a balance between the flexibility of the sheet and physical properties such as surface appearance and abrasion resistance can be obtained. By setting the above-mentioned viscosity to be 10 mPa·s or more, more preferably 15 mPa·s or more, it is possible to suppress the formation of an extreme migration structure. On the other hand, by setting the viscosity to be 70 mPa·s or less, more preferably 50 mPa·s or less, and still more preferably 40 mPa·s or less, the fibrous base material can be easily impregnated with PVA.

In the present invention, the glass transition temperature (Tg) of PVA is preferably 70 to 100°C. By setting the glass transition temperature of PVA to 70° C. or higher, more preferably 75° C. or higher, softening in the drying step can be prevented, dimensional stability of the fibrous substrate can be obtained, and deterioration of the surface appearance of the sheet can be suppressed. Furthermore, by making the glass transition temperature 100° C. or lower, more preferably 95° C. or lower, it is possible to prevent the fibrous base material from becoming too hard and degrading the handleability.

In the present invention, the melting point of PVA is preferably 200 to 250°C. By setting the melting point of PVA to 200° C. or higher, more preferably 210° C. or higher, softening in the drying step can be prevented, dimensional stability of the fibrous substrate can be obtained, and deterioration of the surface appearance of the sheet can be suppressed. In addition, by setting the melting point of PVA to be 250° C. or lower, more preferably 240° C. or lower, it is possible to prevent the fibrous base material from becoming too hard and degrading handling properties.

In the present invention, the tensile strength of the PVA film is preferably 400 to 800 kg/cm ² . By setting the tensile strength of the PVA film to 400 kg/cm ² or more, more preferably 450 kg/cm ² or more, it is possible to suppress dimensional changes during handling and to suppress deterioration of the surface appearance of the sheet. By setting the tensile strength of the PVA film to 800 kg/cm ² or less, more preferably 750 kg/cm ² or less, the PVA-applied sheet does not become too hard, and the occurrence of buckling and wrinkling during handling can be suppressed. In addition, the tensile strength here is the value measured about the 100-micrometer-thick film of PVA in the atmosphere of temperature 20 degreeC, and humidity 65%.

[Second process]

Next, the second step will be described, that is, the PVA aqueous solution is applied to the fibrous base material mainly composed of microfiber-developing fibers, thereby imparting 0.1 to 50% by mass to the fiber mass contained in the fibrous base material. The process of the PVA.

The fibrous base material of the present invention has microfiber-revealing fibers as a main constituent. By using ultra-fine fiber display type fibers, the fibers can be ultra-fine through the subsequent fiber ultra-fine process, and a beautiful surface appearance can be obtained.

In a preferred embodiment of the present invention, the average single fiber diameter of the ultrafine fibers obtained from the ultrafine fiber-developing fibers through the fiber ultra-fine-graining step is 0.3 to 7 μm. When the average single fiber diameter is 7 μm or less, more preferably 6 μm or less, still more preferably 5 μm or less, a sheet-like article having excellent flexibility and pile quality can be obtained. On the other hand, by setting the average single fiber diameter to 0.3 μm or more, more preferably 0.7 μm or more, and even more preferably 1 μm or more, the color development after dyeing and the dispersibility of bundled fibers during pile treatment such as grinding with sandpaper etc. Excellent, and also excellent in ease of fiber opening.

As the above-mentioned microfiber display type fiber, the following fibers can be used: (a) thermoplastic resins of two components with different solvent solubility are used as the sea component and the island component, and the sea component is dissolved and removed by using a solvent, thereby making the island component Island-in-the-sea fibers of superfine fibers; (b) two-component thermoplastic resins are arranged radially or multi-layered alternately on the cross-section of the fibers, and the components are separated by peeling, thereby splitting the fibers into superfine fibers. fiber etc. Among them, the island-in-the-sea fibers can provide appropriate gaps between island components, that is, between microfibers, by removing the sea component, so they can also be preferably used from the viewpoint of flexibility and texture of the sheet.

The island-in-the-sea fiber includes, for example, the following fibers: a sea-island composite fiber in which two components, a sea component and an island component, are aligned and spun using a nozzle for sea-island composite; a sea-island component and an island component are mixed Mixed spun fibers to be spun, etc. Sea-island type composite fibers are preferably used in view of obtaining ultrafine fibers of uniform fineness and obtaining sufficiently long ultrafine fibers, which are also beneficial to the strength of the sheet.

The island component of the sea-island fiber is not particularly limited, and polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polylactic acid can be used, 6-Nylon and 66-Nylon and other polyamides, acrylic, polyethylene, polypropylene, and thermoplastic cellulose fibers made of melt-spinnable thermoplastic resins. Among them, polyester fibers are preferably used from the viewpoint of strength, dimensional stability, and light resistance. In addition, fibers obtained from recycled (recyle) raw materials and plant-derived raw materials are preferable from the viewpoint of environmental friendliness. Furthermore, the fibrous base material may be formed by mixing fibers of different raw materials.

The sea component of the island-in-the-sea fiber is not particularly limited, and for example, polyethylene, polypropylene, polystyrene, copolyester and polylactic acid obtained by copolymerizing sodium sulfonate isophthalate, polyethylene glycol, etc. can be used, PVA, etc. Among them, from the viewpoint of environmental friendliness, alkali-decomposable copolyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, etc., which can be decomposed without using an organic solvent, or polylactic acid, dissolved in hot water, etc., are preferable. Sexual PVA.

The cross-sectional shape of the fibers constituting the fibrous substrate is not particularly limited, and may be a circular cross-section, or a special-shaped cross-section such as an ellipse, flat, triangular, fan-shaped, or cross-shaped.

In the present invention, the average single fiber diameter of the fibers constituting the fibrous base material is preferably 0.3 to 20 μm. The finer the average single fiber diameter, the more flexible and pile quality sheets can be obtained. On the other hand, since the average single fiber diameter is larger, the color development after dyeing, pile treatment such as grinding with sandpaper, etc. The more excellent the dispersibility and easiness of fiber-opening of bundled fibers, the more preferable the average single fiber diameter is 0.7 to 15 μm, and particularly preferably 1 to 7 μm.

As the form of the fibrous base material of the present invention, woven fabrics, knitted fabrics, non-woven fabrics, and the like can be used. Among them, a nonwoven fabric can be preferably used because the surface appearance of the sheet-like article is good when the surface is raised.

The non-woven fabric can be any of the short-fiber non-woven fabric and the long-fiber non-woven fabric, but compared with the short-fiber non-woven fabric, the long-fiber non-woven fabric faces the side of the sheet-like material that becomes the pile when piled up. When there are few fibers in the thickness direction, the dense feeling of the pile tends to be low and the surface appearance tends to be poor, so short-fiber nonwoven fabrics can be preferably used.

The fiber length of the short fibers in the short-fiber nonwoven fabric is preferably 25 to 90 mm. By making the fiber length 25 mm or more, a sheet-shaped article excellent in abrasion resistance can be obtained by entanglement. In addition, by making the fiber length 90 mm or less, a sheet-shaped article excellent in texture and quality can be obtained. The fiber length is more preferably 30 to 80 mm.

As a method of entangling the fibers or fiber bundles of the nonwoven fabric, needle punch or water jet punch can be used.

In the present invention, when the fibrous substrate made of ultrafine fibers is a nonwoven fabric, it is preferable that the nonwoven fabric has a structure in which bundles of ultrafine fibers (ultrafine fiber bundles) are entangled. The strength of the sheet is enhanced by the entanglement of the microfibers in a bundle state. The nonwoven fabric of the above-mentioned aspect can be obtained by entanglement of microfiber-displaying fibers in advance, and then displaying superfine fibers.

When the ultrafine fiber or its ultrafine fiber bundle constitutes a nonwoven fabric, it may be entangled with a woven or braided fabric for the purpose of increasing its internal strength or the like. For example, in the case of a fabric, plain weave, twill weave, satin weave, etc. are mentioned, and a plain weave can be used preferably from a cost point. Moreover, when it is a knitted fabric, a circular knitted fabric, a tricot knitted fabric, a Raschel warp knitted fabric, etc. are mentioned. The average single fiber diameter of the fibers constituting the woven and braided fabrics is preferably 0.3 to 20 μm.

As a preferred mode of the present invention, when fabrics and/or braids are intertwined and integrated inside the fibrous base material mainly composed of microfiber-displaying fibers, PVA is added, and the water-dispersed polyurethane that is added thereafter is directly held. The area of the fabric and/or braid is reduced, which results in a softer feel to the sheet, especially when the fabric and/or braid is made of fibers other than microfibre-revealing fibers, a noticeable softness can be obtained effect.

The amount of PVA provided to the fibrous base material is 0.1 to 50% by mass, preferably 1 to 45% by mass, based on the fiber mass of the fibrous base material. When the amount of PVA added is 0.1% by mass or more, a sheet with good flexibility and texture can be obtained, and when the amount of PVA added is 50% by mass or less, good processability and good physical properties such as abrasion resistance can be obtained. of flakes.

In the present invention, the method of imparting PVA to the fibrous base material is not particularly limited, and various methods generally used in this field can be employed. However, from the viewpoint of uniformly imparting PVA, it is preferable to dissolve PVA in water and impregnate it in water. A method of heating and drying in a fibrous substrate. Regarding the drying temperature, since the temperature is too low, a long drying time is required, and when the temperature is too high, PVA will be insoluble and cannot be dissolved and removed afterwards. Therefore, drying is preferably carried out at 80-140°C, and the drying temperature is more preferably 110-130°C. The drying time is usually 1 to 20 minutes, preferably 1 to 10 minutes, more preferably 1 to 5 minutes from the viewpoint of workability. In addition, in order to further insolubilize PVA, heat treatment may be performed after drying. The preferable temperature of heat processing is 80-170 degreeC. Since insolubilization of PVA and thermal deterioration of PVA proceed simultaneously by heat treatment, a more preferable temperature is 80-140 degreeC.

[3rd process]

Next, the third step, that is, the step of developing ultrafine fibers having an average single fiber diameter of 0.3 to 7 μm from a fibrous base material mainly composed of ultrafine fiber developing fibers will be described.

The fiber ultrafine treatment (sea removal treatment) of the fibrous base material mainly composed of microfiber-developing fibers can be carried out by immersing the fibrous base material in a solvent and extruding the liquid. When the microfiber display fiber is an island-in-the-sea fiber, as a solvent, when the sea component is polyethylene, polypropylene, or polystyrene, organic solvents such as toluene and trichlorethylene can be used, and when the sea component is copolyester Or in the case of polylactic acid, an alkaline aqueous solution such as sodium hydroxide can be used. In addition, when the sea component is PVA, hot water can be used. From the standpoint of environmental friendliness of the process, desea treatment is preferably performed with an alkaline aqueous solution such as sodium hydroxide or hot water.

[4th process]

Next, the fourth step, that is, the step of applying water-dispersible polyurethane to the fibrous base material to which PVA is applied and mainly composed of microfibers will be described.

The above-mentioned water-dispersible polyurethanes are classified into: (I) forced emulsification polyurethanes that are forcibly dispersed and stabilized in water using surfactants; and (II) polyurethanes that have a hydrophilic structure in the molecular Any self-emulsifying polyurethane that can be dispersed and stabilized in water as an agent can be used in the present invention.

The method of applying water-dispersible polyurethane to the fibrous base material is not particularly limited, and the method of impregnating and applying the water-dispersible polyurethane solution to the fibrous base material, solidifying it, and heating and drying it can be uniformly applied, so it is preferred.

The concentration of the water-dispersible polyurethane liquid (the content of polyurethane relative to the water-dispersible polyurethane liquid) is preferably 10 to 50% by mass, more preferably 15 to 50% by mass, from the viewpoint of storage stability of the water-dispersible polyurethane liquid. 40% by mass.

In addition, in order to improve storage stability and film-forming properties, the water-dispersed polyurethane liquid used in the present invention may contain a water-soluble organic solvent of 40% by mass or less relative to the polyurethane liquid, but from the perspective of maintaining the film-forming environment, etc. , It is preferable to make content of an organic solvent into 1 mass % or less.

In addition, the water-dispersed polyurethane liquid used in the present invention preferably has thermosetting properties. By using a thermosetting water-dispersible polyurethane liquid, polyurethane can be uniformly applied in the thickness direction of the fibrous substrate.

In the present invention, the thermal coagulation property refers to the property that the fluidity of the polyurethane fluid decreases and solidifies when the polyurethane fluid reaches a certain temperature (thermal coagulation temperature) when it is heated. When manufacturing a polyurethane-attached sheet, after the polyurethane liquid is applied to the fibrous substrate, it is solidified by dry coagulation, wet heat coagulation, wet coagulation, or a combination thereof, and then dried, so that the fibrous substrate Imparts polyurethane. As a method of coagulating a water-dispersed polyurethane solution that does not exhibit thermosetting properties, dry coagulation is practical in industrial production, but in this case, the migration phenomenon of polyurethane concentrated on the surface layer of the fibrous substrate will occur, with The feel of the polyurethane sheet tends to harden. In this case, migration can be prevented by adjusting the viscosity of the water-dispersed polyurethane liquid with a thickener. In addition, in the case of a water-dispersed polyurethane solution exhibiting thermosetting properties, migration can also be prevented by adding a thickener and performing dry coagulation.

The thermal coagulation temperature of the water-dispersed polyurethane liquid is preferably 40 to 90°C. By setting the thermal coagulation temperature at 40° C. or higher, the stability of the polyurethane liquid during storage becomes favorable, and it is possible to suppress adhesion of polyurethane to equipment during handling, and the like. In addition, by setting the thermal coagulation temperature at 90° C. or lower, migration of polyurethane to the surface layer of the fibrous base material can be suppressed.

In one aspect of the present invention, a thermal coagulation agent may be appropriately added so that the thermal coagulation temperature is as described above. Examples of thermocoagulants include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate, and calcium chloride; sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, and benzoyl peroxide; Free radical reaction initiator, etc.

In a preferred embodiment of the present invention, the polyurethane liquid can be impregnated and coated on the fibrous substrate, and the polyurethane can be coagulated by dry coagulation, wet heat coagulation, wet coagulation or a combination thereof.

The moisture coagulation temperature is preferably not less than the thermal coagulation temperature of polyurethane, preferably 40 to 200°C. By setting the wet heat coagulation temperature to be 40° C. or higher, more preferably 80° C. or higher, it is possible to shorten the time until the polyurethane solidifies, and further suppress the migration phenomenon. On the other hand, by setting the temperature of wet heat coagulation to be 200° C. or lower, more preferably 160° C. or lower, thermal deterioration of polyurethane and PVA can be prevented.

The above-mentioned wet coagulation temperature is preferably not less than the thermal coagulation temperature of polyurethane, and is 40 to 100°C. By setting the wet coagulation temperature in hot water to be 40° C. or higher, more preferably 80° C. or higher, the time until the polyurethane is solidified can be shortened, and the migration phenomenon can be further suppressed.

The above-mentioned dry coagulation temperature and drying temperature are preferably 80 to 140°C. When the dry coagulation temperature and the drying temperature are 80° C. or higher, more preferably 90° C. or higher, the productivity is excellent. On the other hand, by setting the dry coagulation temperature and drying temperature to be 140° C. or lower, more preferably 130° C. or lower, thermal deterioration of polyurethane and PVA can be prevented.

In the present invention, heat treatment may be performed after solidifying polyurethane. By performing heat treatment, the interface between polyurethane molecules is reduced, resulting in stronger polyurethane. In a more preferable embodiment, heat treatment is preferably performed after removing PVA from the water-dispersible polyurethane-applied sheet. The temperature of the heat treatment is preferably 80 to 170°C.

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

The above-mentioned polymer diol is not particularly limited, and for example, polycarbonate-based, polyester-based, polyether-based, silicone-based, and fluorine-based diols can be used, and copolymers obtained by combining them can also be used. . From the viewpoint of hydrolysis resistance, polycarbonate-based and polyether-based diols can be preferably used. In addition, polycarbonates and polyesters can be preferably used from the viewpoint of light resistance and heat resistance. Furthermore, from the viewpoint of the balance among hydrolysis resistance, heat resistance, and light resistance, polycarbonate-based and polyester-based diols are more preferable, and polycarbonate-based diols can be used particularly preferably.

The above polycarbonate diol can be produced by transesterification of an alkylene glycol and a carbonate, or reaction of phosgene or chloroformate with an alkylene glycol, or the like.

The above-mentioned alkylene glycol is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,9-nonanediol. Diol, 1,10-decanediol and other linear alkylene glycols; neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol Alcohol, 2-methyl-1,8-octanediol and other branched alkylene glycols; 1,4-cyclohexanediol and other alicyclic diols, bisphenol A and other aromatic diols; glycerine alcohol, trimethylolpropane and pentaerythritol, etc. It may be a polycarbonate-based diol obtained from each individual alkylene glycol, or may be a copolycarbonate-based diol obtained from two or more kinds of alkylene glycols.

As said polyester diol, the polyester diol obtained by condensing various low-molecular-weight polyols and a polybasic acid is mentioned.

The above-mentioned low-molecular-weight polyhydric alcohol is not particularly limited, and for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2, 2-Dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, bis One or more of propylene glycol, tripropylene glycol, cyclohexane-1,4-diol and cyclohexane-1,4-dimethanol. In addition, adducts obtained by adding various alkylene oxides to bisphenol A can also be used.

In addition, the above-mentioned polybasic acid is not particularly limited, and examples thereof include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanoic acid, One or more of alkanedioic acid, phthalic acid, isophthalic acid, terephthalic acid and hexahydroisophthalic acid.

It does not specifically limit as said polyether diol, For example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the copolymerized glycol which combined them are mentioned.

The number average molecular weight of the polymer diol used in the present invention is preferably 500-4000. By setting the number average molecular weight to be 500 or more, more preferably 1500 or more, it is possible to prevent the texture from becoming hard. In addition, the strength as polyurethane can be maintained by setting the number average molecular weight to 4000 or less, more preferably 3000 or less.

The above-mentioned organic diisocyanate is not particularly limited, and examples thereof include aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, diphenylene diisocyanate, and diphenylene diisocyanate. Aromatic diisocyanates, such as methyl methane diisocyanate and toluene diisocyanate, can also be used in combination with the above-mentioned organic diisocyanate. Among them, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate can be preferably used from the viewpoint of light resistance.

The above-mentioned chain extender is not particularly limited, and chain extenders of amines such as ethylenediamine and methylenebisaniline, and chain extenders of glycols such as ethylene glycol can be used. In addition, a polyamine obtained by reacting a polyisocyanate with water can also be used as a chain extender.

For the purpose of improving water resistance, abrasion resistance, hydrolysis resistance, etc., a crosslinking agent may be used in combination with polyurethane as desired. The cross-linking agent may be an external cross-linking agent added as a third component to the polyurethane, or an internal cross-linking agent previously introduced into the molecular structure of the polyurethane to form a cross-linking structure. In the present invention, it is preferable to use an internal crosslinking agent from the viewpoint that crosslinking points can be relatively uniformly formed in the molecular structure of the polyurethane and a decrease in flexibility can be reduced.

As said crosslinking agent, the compound which has an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, etc. can be used. Among them, when the crosslinking progresses excessively, the polyurethane tends to harden and the feel of the sheet-like article tends to become hard. Therefore, a crosslinking agent having a silanol group is preferably used in view of the balance between reactivity and flexibility.

Furthermore, the polyurethane used in the present invention preferably has a hydrophilic group in the molecular structure. By having a hydrophilic group in the molecular structure, dispersion and stability as a water-dispersible polyurethane can be improved.

As the above-mentioned hydrophilic group, for example, cations such as quaternary ammonium salts, anions such as sulfonates and carboxylates, nonionics such as polyethylene glycol, combinations of cationics and nonionics, and anionics can be used. Any hydrophilic group in combination with nonionics. Among them, nonionic hydrophilic groups (which have no fear of yellowing by light and disadvantages by neutralizing agents) can be particularly preferably used.

It should be noted that when it is an anionic hydrophilic group, a neutralizing agent becomes necessary, for example, the neutralizing agent is ammonia, triethylamine, triethanolamine, triisopropanolamine, trimethylamine and dimethyl In the case of tertiary amines such as ethanolamine, the amine is generated and volatilized due to the heat during film formation and drying, and is released outside the system. Therefore, it is necessary to introduce a device for recovering volatilized amines in order to suppress air emissions and deterioration of the work environment. In addition, it is considered that when the amine remains in the final product, that is, the sheet without being volatilized by heating, it is considered to be discharged into the environment when the product is incinerated or the like. On the other hand, since a nonionic hydrophilic group does not use a neutralizing agent, it is not necessary to introduce an amine recovery device, and there is no worry of amine remaining in the sheet, so it can be preferably used.

In addition, when the neutralizing agent of the above-mentioned anionic hydrophilic group is alkali metal or alkaline earth metal hydroxide such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, the polyurethane part will show alkalinity when it is wetted. , and when it is a nonionic hydrophilic group, since no neutralizing agent is used, there is no need to worry about deterioration caused by hydrolysis of polyurethane.

The water-dispersible polyurethane used in the present invention may contain various additives as desired, for example, pigments such as carbon black, flame retardants such as phosphorus, halogen, silicone and inorganic, phenols, sulfur and phosphorus Antioxidants such as benzotriazoles, benzophenones, salicylates, cyanoacrylates and oxalanilides and other UV absorbers, hindered amines, benzoate and other light stabilizers, Hydrolysis-resistant stabilizers such as polycarbodiimide, plasticizers, antistatic agents, surfactants, softeners, waterproofing agents, coagulation regulators, viscosity regulators, dyes, preservatives, antibacterial agents, deodorants, fibers Fillers such as plain particles and microspheres, and inorganic particles such as silica and titanium oxide. In addition, inorganic materials such as sodium bicarbonate, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], etc. may be contained in order to increase the gap between the fiber and polyurethane Organic blowing agent.

In the present invention, the content ratio of polyurethane is preferably 1 to 80% by mass relative to the fibrous base material mainly composed of ultrafine fibers. When the ratio of the polyurethane is 1% by mass or more, more preferably 5% by mass or more, sheet strength can be obtained, and fiber dropout can be prevented. In addition, when the compounding ratio of polyurethane is 80% by mass or less, more preferably 70% by mass or less, it is possible to prevent the texture from becoming hard and obtain good pile quality.

[5th process]

Next, the fifth step, that is, the step of removing PVA from the fibrous base material mainly composed of microfibers to which PVA and water-dispersed polyurethane are applied, will be described.

In a preferred embodiment of the present invention, a flexible sheet is obtained by removing PVA from the fibrous substrate to which polyurethane has been applied. The method of removing PVA is not particularly limited. For example, a preferable method is to dissolve and remove PVA by immersing the sheet in hot water at 60 to 100° C., and squeezing out the liquid with a liquid squeezer if necessary.

The method for producing a sheet-like article according to the present invention may include at least the step of cutting the PVA-applied fibrous base material in half in the thickness direction after applying water-dispersible polyurethane. In the process of applying PVA, a large amount of PVA adheres to the surface layer of the fibrous substrate due to migration, and the amount of PVA adhered to the inner layer is small. Then, after adding water-dispersible polyurethane, it is cut in half along the thickness direction to obtain a sheet with the following structure: a small amount of water-dispersible polyurethane is attached to the side with a large amount of PVA attached, and a small amount of water-dispersed polyurethane is attached to the side where PVA is attached. A structure in which a large amount of water-dispersible polyurethane is attached to the side with a small amount. When the surface to which a large amount of PVA is attached (the surface to which water-dispersed polyurethane is less adhered) is used as the pile surface of the sheet, since PVA is already applied, a large gap is generated between the polyurethane and the microfibers constituting the pile, which affects the structure. The fibers of the pile give freedom, the surface texture becomes soft, and good appearance quality and soft texture can be obtained. On the contrary, when the surface to which a small amount of PVA is attached (the surface to which water-dispersed polyurethane is attached more) is used as the pile surface of the sheet, although the fibers constituting the pile are strongly held by the polyurethane, the pile length is relatively short, but it can be obtained. Good appearance quality with dense feeling, and further wear resistance becomes good. Furthermore, production efficiency can be improved by including the process of cutting in half in the thickness direction of a sheet|seat.

In the present invention, at least one side of the sheet-like object may be raised to form piles on the surface. The method of forming the pile is not particularly limited, and various methods generally used in this field (polishing with sandpaper or the like, etc.) can be employed. When the pile length is too short, it is difficult to obtain a beautiful appearance, and when it is too long, pilling tends to easily occur. Therefore, the pile length is preferably 0.2 to 1 mm.

In addition, in one aspect of the present invention, silicone or the like as a lubricant may be provided to the sheet before the napping treatment. By providing a lubricant, napping by surface grinding becomes easy and the surface quality becomes very good, so it is preferable. In addition, an antistatic agent may be added before the napping treatment. By adding an antistatic agent, abrasive dust generated from flakes due to grinding is less likely to accumulate on the sandpaper, so it is a preferred mode.

In one aspect of the present invention, the sheet-like article may be dyed. As the dyeing method, various methods generally used in this field can be adopted, and the method using a liquid flow dyeing machine is preferable from the viewpoint of imparting a rubbing effect and softening the sheet while dyeing the sheet.

The dyeing temperature also varies depending on the type of fiber, but is preferably 80 to 150°C. By setting the dyeing temperature to be 80° C. or higher, more preferably 110° C. or higher, fibers can be efficiently dyed. On the other hand, by setting the dyeing temperature to be 150°C or lower, more preferably 130°C or lower, deterioration of polyurethane can be prevented.

The dye used in the present invention can be selected according to the type of fiber constituting the fibrous substrate, and is not particularly limited. For example, if it is a polyester fiber, a disperse dye can be used, and if it is a polyamide fiber, an acid dye can be used. dyes or gold-containing dyes, and combinations thereof can be used. When dyeing with disperse dyes, reduction cleaning can be carried out after dyeing.

In addition, it is also preferable to use dyeing auxiliaries at the time of dyeing. By using dyeing auxiliaries, the uniformity and reproducibility of dyeing can be improved. In addition, in the same bath as the dyeing or after dyeing, a modifier treatment using a softener such as silicone, an antistatic agent, a water repellant, a flame retardant, a light-resistant agent, and an antibacterial agent can be performed.

The density of the sheet-shaped article of the present invention obtained through the above operations is preferably 0.2 to 0.7 g/cm ³ . By making the density 0.2 g/cm ³ or more, more preferably 0.3 g/cm ³ or more, the surface appearance becomes dense, and superior quality can be expressed. On the other hand, by making the density 0.7 g/cm ³ or less, more preferably 0.6 g/cm ³ or less, it is possible to prevent the feel of the sheet from becoming hard.

[Example]

Next, the manufacturing method of the sheet-shaped article of the present invention will be described in more detail through examples, but the present invention is not limited to these examples, and those skilled in the art can make various modifications within the technical concept of the present invention.

[Evaluation method]

(1) Organic solvent concentration of PVA aqueous solution

1 g of PVA aqueous solution was charged into a 24 mL heating tube, and heated at 90° C. for 1 hour. Collect 0.1 mL of generated gas from the heating tube with an air-tight injection needle, introduce it into GC/MS, and analyze the concentration of methyl acetate, acetic acid, and methanol. It should be noted that the detection limit of GC/MS is lower than 0.1 ppm.

(2) Viscosity of PVA aqueous solution

The viscosity at 20° C. of a 4 mass % PVA aqueous solution was measured by the rotational viscometer method described in 3.11.1 of JIS K6726 (1994) polyvinyl alcohol test method.

(3) Tensile strength of PVA

10% by mass of PVA water dispersion was added to polyethylene trays (5 cm in length, 10 cm in width, and 1 cm in depth), and after air-drying at 25° C. for 8 hours, heat treatment with a hot air dryer at 120° C. for 2 hours to obtain PVA dry film with a thickness of 100μm. About this PVA dry film, the tensile strength was measured using the tensile testing machine according to A method (strip method) described in JIS L1096 (2010) 8.14.1.

(4) Average single fiber diameter

The average single fiber diameter was calculated by taking a scanning electron microscope (SEM) photograph of the surface of the fibrous substrate or sheet at a magnification of 2000 times, randomly selecting 100 fibers, measuring the single fiber diameter, and calculating the average value.

When the fibers constituting the fibrous base material or the sheet have a profiled cross section, the diameter of the outer circumference of the profiled section is calculated as the diameter of the single fiber. In addition, when a circular cross section and a special-shaped cross section are mixed, and when cross sections having significantly different single fiber diameters are mixed, etc., the number of samples corresponding to the ratio of the number of existing fibers is selected and calculated, and a total of 100 fibers are calculated. However, in the case where a reinforcing fabric or braid is inserted into the fibrous base material, fibers of the reinforcing fabric or braid are not included in the sampling target when measuring the average single fiber diameter.

(5) Stiffness of sheet

Based on the A method (45° cantilever method) recorded in JIS L1096 (2010) 8.21.1, a test piece of 2 cm × 15 cm in the longitudinal direction and the transverse direction was made, and placed on a horizontal platform with a 45° inclined plane. Slide the piece, and read the position of the other end of the test piece when the central point of one end of the test piece is in contact with the inclined surface through the scale. The stiffness is represented by the length (mm) of movement of the test piece. The average value of the moving lengths of the five test pieces was determined as the stiffness.

(6) Surface appearance of flakes

Regarding the surface appearance of the sheet, 10 adult males and 10 adult females (total 20) in good health were used as evaluators, and the following 5-level evaluations were performed by visual and sensory evaluations, and the most evaluations were taken as surface appearance. The surface appearance is considered good in grades 3 to 5.

Grade 5: There is uniform fiber pile, the dispersed state of fibers is good, and the appearance is good.

Level 4: An evaluation between Level 5 and Level 3.

Grade 3: There is a part where the dispersed state of the fiber is slightly bad, but there is fiber tuft, and the appearance is relatively good.

Level 2: An evaluation between Level 3 and Level 1.

Grade 1: The dispersed state of the fibers as a whole is very poor, or the fiber pile is long, and the appearance is not good.

(7) Evaluation of wear resistance of sheet

Nylon fibers with a diameter of 0.4 mm formed by nylon 6 are cut into lengths of 11 mm in a direction perpendicular to the longitudinal direction of the fibers, and 100 cut fibers are neatly bundled, and 97 of these fiber bundles are arranged in a circle with a diameter of 110 mm. 6 concentric circles (1 in the center, 6 in a circle with a diameter of 17mm, 13 in a circle with a diameter of 37mm, 19 in a circle with a diameter of 55mm, 26 in a circle with a diameter of 74mm, 32 in a circle with a diameter of 90mm, Circular brushes (9700 nylon filaments) that are equally spaced in each circle) make circular samples of flakes (diameter 45mm) surface wear, the mass change of the sample before and after the wear was measured, and the average value of the mass change of five samples, that is, the wear loss (mg) was regarded as the wear resistance.

[Example 1]

(Preparation of PVA aqueous solution)

PVA with a degree of saponification of 99% and a degree of polymerization of 1400 (NM-14 manufactured by Nippon Synthetic Chemicals Co., Ltd.) was added to water at 25°C, heated to 90°C, and kept at 90°C while stirring for 2 hours to prepare solid component 10. mass % aqueous solution to obtain PVA aqueous solution. The concentrations of methyl acetate, acetic acid, and methanol contained in the PVA aqueous solution were 10.2 ppm, 0.8 ppm, and 5.2 ppm, respectively.

(Non-woven fabrics for fibrous substrates)

As the sea component, polyethylene terephthalate copolymerized with 8 mol% of isophthalic acid-5-sulfonate sodium was used, as the island component, polyethylene terephthalate was used, and the sea component was 45 % by mass and a composite ratio of 55% by mass of the island component, an island-in-sea type composite fiber with an island number of 36 islands/1 fiber and an average single fiber diameter of 17 μm was obtained. The obtained island-in-the-sea composite fibers were cut into fibers with a fiber length of 51 mm as staple fibers (staples), and a fiber web was formed by a carding machine and a cross-lapper, and a nonwoven fabric was obtained by needle punching. The nonwoven fabric obtained by the above operation was immersed in hot water at a temperature of 98° C. for 2 minutes to shrink it, and dried at a temperature of 100° C. for 5 minutes to obtain a nonwoven fabric for a fibrous base material.

(grant of PVA)

The above-mentioned PVA aqueous solution was impregnated into the above-mentioned nonwoven fabric for fibrous substrate, and heat-dried at a temperature of 140° C. for 10 minutes to obtain a PVA-applied sheet. The fiber mass (in terms of the amount of PVA attached) was 30% by mass.

(fiber superfine (removal of sea))

The PVA-coated sheet was immersed in an aqueous solution of sodium hydroxide heated to a temperature of 95° C. with a concentration of 10 g/liter for 30 minutes to obtain a sea-removing sheet from which the sea component of the sea-island composite fiber was removed. The average single fiber diameter on the surface of the desealing sheet was 3 μm.

(Preparation of Polyurethane Liquid)

With respect to the solid content of 100 parts by mass of polycarbonate self-emulsifying polyurethane liquid (using polyhexamethylene carbonate as polyol and dicyclohexylmethane diisocyanate as isocyanate), 2 parts by mass of The ammonium persulfate (APS) of the thermal coagulant was prepared as a whole with water so as to have a solid content of 20% by mass to obtain a water-dispersed polyurethane liquid. The thermosetting temperature is 72°C.

(endowment of polyurethane)

The above-mentioned polycarbonate-based polyurethane solution was impregnated into the above-mentioned PVA-imparted sea-removing sheet, and after being treated for 5 minutes in a humid heat atmosphere at a temperature of 100°C, it was dried with hot air at a drying temperature of 120°C for 5 minutes, and then Dry heat treatment was performed at a temperature of 140° C. for 2 minutes to obtain a polyurethane-imparted sheet having an adhesion amount of polyurethane (with respect to the fiber mass of the nonwoven fabric) of 30% by mass.

(exclusion of PVA)

The polyurethane-coated sheet was dipped in water heated to 95° C. and treated for 10 minutes to obtain a sheet from which the PVA provided was removed.

(half-cut · fleece · dyed · reduction cleaning)

The above-mentioned sheet from which PVA was removed was cut in half in the thickness direction, and the half-cut surface and the opposite surface were subjected to napping treatment by grinding with 240 mesh endless sandpaper, and then used a liquid flow dyeing machine (Circular) to utilize Dyeing with disperse dyes, and performing reduction cleaning to obtain flakes. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 2]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

It carried out similarly to Example 1, and obtained the nonwoven fabric for fibrous base materials.

(grant of PVA)

Using the same PVA aqueous solution as in Example 1, adjusting the squeeze after impregnation to change the adhesion amount of PVA, except that, operate in the same manner as in Example 1 to obtain the adhesion amount of PVA (with respect to the fibrous base material. A PVA-imparted sheet containing 20% by mass in terms of the fiber mass of the cloth.

(fiber superfine (removal of sea))

In the same manner as in Example 1, a sea-removing sheet was obtained.

(Preparation of Polyurethane Liquid)

In the same manner as in Example 1, a water-dispersed polyurethane liquid was obtained.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 3]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium isophthalate-5-sulfonate was used, and as the island component, polyethylene terephthalate was used, and the sea component was 20 % by mass and a composite ratio of 80% by mass of the island component, an island-in-sea type composite fiber with an island number of 16 islands/1 fiber and an average single fiber diameter of 30 μm was obtained. The obtained island-in-the-sea composite fibers were cut into fibers with a fiber length of 51 mm as cut fibers, and a fiber web was formed by a carding machine and a cross-lapper, and a nonwoven fabric was formed by needle punching. The nonwoven fabric obtained by the above operation was immersed in hot water at a temperature of 98° C. for 2 minutes to shrink it, and dried at a temperature of 100° C. for 5 minutes to obtain a nonwoven fabric for a fibrous base material.

(grant of PVA)

Using the same PVA aqueous solution as in Example 1, a PVA-imparted sheet having a PVA adhesion amount (with respect to the fiber mass of the nonwoven fabric for a fibrous base material) of 30% by mass was obtained.

(fiber superfine (removal of sea))

The fibrous base material was treated with a nonwoven fabric in the same manner as in Example 1 to obtain a sea-removing sheet from which the sea component of the sea-island type composite fiber was removed. The average single fiber diameter on the surface of the desealing sheet was 4.4 μm.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 4]

(Preparation of PVA aqueous solution)

PVA (NM-11 manufactured by Nippon Synthetic Chemicals Co., Ltd.) with a degree of saponification of 99% and a degree of polymerization of 1100 was added to water at 25°C, heated to 90°C, and kept at 90°C while stirring for 2 hours to prepare solid component 10. mass % aqueous solution to obtain PVA aqueous solution. The concentrations of methyl acetate, acetic acid, and methanol contained in the PVA aqueous solution were 7.2 ppm, 0.4 ppm, and 2.4 ppm, respectively.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

The above-mentioned PVA aqueous solution was impregnated into the above-mentioned non-woven fabric for fibrous substrates, and heated and dried at a temperature of 140° C. for 10 minutes to obtain the adhesion amount of PVA (relative to the fiber mass of the non-woven fabrics for fibrous substrates) ) is a PVA-imparted sheet of 30% by mass.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 5]

(Preparation of PVA aqueous solution)

Add PVA with a degree of saponification of 99% and a degree of polymerization of 2600 (NH-26 manufactured by Nippon Synthetic Chemicals Co., Ltd.) to water at 25°C, raise the temperature to 90°C, and keep it at 90°C while stirring for 2 hours to prepare a solid content of 10 mass % aqueous solution to obtain PVA aqueous solution. The concentrations of methyl acetate, acetic acid, and methanol contained in the PVA aqueous solution were 32.2 ppm, 8.3 ppm, and 20.1 ppm, respectively.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

The above-mentioned PVA aqueous solution was impregnated into the above-mentioned non-woven fabric for fibrous substrates, and heated and dried at a temperature of 140° C. for 10 minutes to obtain the adhesion amount of PVA (relative to the fiber mass of the non-woven fabrics for fibrous substrates) ) is a PVA-imparted sheet of 10% by mass.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 6]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium isophthalate-5-sulfonate was used, and as the island component, polyethylene terephthalate was used, and the sea component was 20 % by mass and a composite ratio of 80% by mass of the island component, an island-in-sea type composite fiber with an island number of 16 islands/1 fiber and an average single fiber diameter of 30 μm was obtained. The obtained island-in-the-sea composite fibers were cut into fibers with a fiber length of 51 mm as cut fibers, and a fiber web was formed by a carding machine and a cross-lapper, and polyethylene terephthalate (PET) was laminated on both sides of the web. 84dtex-72f, plain weave fabric of strongly twisted yarn with a twist of 2000T/m, made into non-woven fabric through needle punching. The nonwoven fabric obtained by the above operation was immersed in hot water at a temperature of 98° C. for 2 minutes to shrink it, and dried at a temperature of 100° C. for 5 minutes to obtain a nonwoven fabric for a fibrous base material.

(grant of PVA)

The above-mentioned PVA aqueous solution was impregnated into the above-mentioned non-woven fabric for fibrous substrates, and heated and dried at a temperature of 140° C. for 10 minutes to obtain the adhesion amount of PVA (relative to the fiber mass of the non-woven fabrics for fibrous substrates) ) is a PVA-imparted sheet of 15% by mass.

(fiber superfine (removal of sea))

The fibrous base material was treated with a nonwoven fabric in the same manner as in Example 1 to obtain a sea-removing sheet from which the sea component of the sea-island type composite fiber was removed. The average single fiber diameter on the surface of the desealing sheet was 4.4 μm.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 7]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

It carried out similarly to Example 1, and obtained the nonwoven fabric for fibrous base materials.

(grant of PVA)

In the same manner as in Example 1, a PVA-imparted sheet was obtained in which the amount of PVA attached (with respect to the fiber mass of the nonwoven fabric for a fibrous base material) was 30% by mass.

(fiber superfine (removal of sea))

In the same manner as in Example 1, a sea-removing sheet was obtained.

(Preparation of Polyurethane Liquid)

With respect to 100 parts by mass of the solid content of polycarbonate self-emulsifying polyurethane liquid (using polyhexamethylene carbonate as polyol and dicyclohexylmethane diisocyanate as isocyanate), add 5 parts by mass of A thickener (SN THICKENER 627N manufactured by SAN NOPCO Ltd.) was prepared as a whole with water to obtain a polyurethane solid content of 20% by mass to obtain a water-dispersed polyurethane liquid.

(endowment of polyurethane)

The above-mentioned polyurethane solution was impregnated into the above-mentioned PVA-applied sea-removing sheet, and dried with hot air at a drying temperature of 100° C. for 30 minutes, thereby obtaining the adhesion amount of polyurethane (relative to the fiber mass of the non-woven fabric) It is a 30% by mass polyurethane-imparted sheet.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Example 8]

(Preparation of PVA aqueous solution)

In the same manner as in Example 5, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

The above-mentioned PVA aqueous solution was impregnated into the above-mentioned non-woven fabric for fibrous substrates, and heated and dried at a temperature of 140° C. for 10 minutes to obtain the adhesion amount of PVA (relative to the fiber mass of the non-woven fabrics for fibrous substrates) ) is a PVA-imparted sheet of 10% by mass.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

With respect to the solid content of 100 parts by mass of polycarbonate self-emulsifying polyurethane liquid (using polyhexamethylene carbonate as polyol and dicyclohexylmethane diisocyanate as isocyanate), 2 parts by mass of The ammonium persulfate (APS) of the thermal coagulant was prepared as a whole with water so as to have a solid content of 20% by mass to obtain a water-dispersed polyurethane liquid. The thermosetting temperature is 72°C.

(endowment of polyurethane)

The above-mentioned polyurethane solution was impregnated into the above-mentioned PVA-coated sea-removing sheet, solidified in warm water at 80° C., and dried with hot air at 100° C. for 15 minutes to obtain the adhesion amount of polyurethane (relative to the amount of non-woven fabric). A polyurethane-imparted sheet having 30% by mass in terms of fiber mass).

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet had a good surface appearance, a soft texture, and good abrasion resistance.

[Comparative example 1]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(fiber superfine (removal of sea))

The fibrous substrate nonwoven fabric obtained by the above operations was immersed in an aqueous solution of sodium hydroxide having a concentration of 10 g/liter heated to 95° C. and treated for 10 minutes to obtain a sea-island composite fiber from which the sea component was removed. De-sea sheet. The average single fiber diameter on the surface of the desealing sheet was 3 μm.

(grant of PVA)

The above-mentioned sea-removing sheet was impregnated with the PVA aqueous solution obtained in Example 1, and heated and dried at a temperature of 140° C. for 10 minutes to obtain a PVA with an adhesion amount (relative to the sea-removing sheet) of 30% by mass. A sheet of PVA is given.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

The above-mentioned polycarbonate-based polyurethane solution was impregnated in the above-mentioned PVA-imparted sea-removing sheet, and after being treated for 5 minutes in a humid heat atmosphere at a temperature of 100°C, it was dried with hot air at a drying temperature of 120°C for 5 minutes, and then dried at 140°C. Dry heat treatment was performed at a temperature of °C for 2 minutes to obtain a polyurethane-imparted sheet having a polyurethane adhesion amount (relative to the ultrafine fiber mass) of 30% by mass.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. Although the obtained sheet had a good surface appearance and a soft texture, it had a large amount of wear loss.

[Comparative example 2]

(Preparation of PVA aqueous solution)

Add PVA (GL-05 manufactured by Nippon Synthetic Chemicals Co., Ltd.) with a degree of saponification of 87% and a degree of polymerization of 500 to water at 25°C, raise the temperature to 90°C, and keep it at 90°C while stirring for 2 hours to prepare a solid content of 10 mass % aqueous solution to obtain PVA aqueous solution. The concentrations of methyl acetate, acetic acid, and methanol contained in the PVA aqueous solution were 70.1 ppm, 40.1 ppm, and 100.3 ppm, respectively.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

The above-mentioned PVA aqueous solution is impregnated in the above-mentioned nonwoven fabric for fibrous substrates, and the amount of adhesion of PVA is changed by adjusting the squeeze after impregnation, except that, in the same manner as in Example 1, the amount of adhesion of PVA (with respect to the fibers) is obtained. A PVA-imparted sheet comprising 10% by mass in terms of the fiber mass of the nonwoven fabric used as the base material.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The resulting sheet was not uniformly imparted because part of the PVA was dissolved in the alkaline aqueous solution and the water-dispersed polyurethane solution, and the surface appearance was not good (fiber dispersion state was poor, and the pile did not feel dense), and the handle was hard.

[Comparative example 3]

(Preparation of PVA aqueous solution)

PVA with a degree of saponification of 99% and a degree of polymerization of 500 (NL-05 manufactured by Nippon Synthetic Chemicals Co., Ltd.) was added to water at 25°C, heated to 90°C, and kept at 90°C while stirring for 2 hours to prepare solid component 10. The aqueous solution of mass %, obtains PVA aqueous solution. The concentrations of methyl acetate, acetic acid, and methanol contained in the PVA aqueous solution were 6.1 ppm, 0.4 ppm, and 1.1 ppm, respectively.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

The above-mentioned PVA aqueous solution is impregnated in the above-mentioned nonwoven fabric for fibrous substrates, and the amount of adhesion of PVA is changed by adjusting the squeeze after impregnation, except that, in the same manner as in Example 1, the amount of adhesion of PVA (with respect to the fibers) is obtained. A PVA-imparted sheet comprising 10% by mass in terms of the fiber mass of the nonwoven fabric used as the base material.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The resulting sheet was not uniformly imparted because part of the PVA was dissolved in the alkaline aqueous solution and the water-dispersed polyurethane solution, and the surface appearance was not good (fiber dispersion state was poor, and the pile did not feel dense), and the handle was hard.

[Comparative example 4]

(Preparation of PVA aqueous solution)

In the same manner as in Example 1, an aqueous PVA solution was obtained.

(Non-woven fabrics for fibrous substrates)

The same nonwoven fabric for fibrous base materials as in Example 1 was used.

(grant of PVA)

Using the same PVA aqueous solution as in Example 1, adjusting the squeeze after impregnation to change the adhesion amount of PVA, except that, operate in the same manner as in Example 1 to obtain the adhesion amount of PVA (with respect to the fibrous base material. A PVA-imparted sheet having 55% by mass in terms of the fiber mass of the cloth.

(fiber superfine (removal of sea))

It carried out similarly to Example 1, and obtained the desealing sheet from the nonwoven fabric for fibrous base materials mentioned above.

(Preparation of Polyurethane Liquid)

The same water-dispersible polyurethane solution as in Example 1 was used.

(endowment of polyurethane)

In the same manner as in Example 1, a polyurethane-imparted sheet was obtained.

(exclusion of PVA)

In the same manner as in Example 1, a sheet from which PVA was removed was obtained.

(half-cut · fleece · dyed · reduction cleaning)

A sheet was obtained in the same manner as in Example 1. The obtained sheet was soft to the touch, but because of too much PVA, the grip of the fibers by the polyurethane was insufficient, the surface appearance was poor (the pile was too long), and the abrasion resistance was poor.

[Comparative Example 5]

Except not performing preparation of PVA aqueous solution, provision and removal of PVA, it carried out similarly to Example 1, and obtained the sheet-like thing. The texture of the obtained sheet became hard. In addition, the surface appearance was poor (no pile).

Table 1 and Table 2 show the test conditions and the evaluation results of the sheets in each Example and Comparative Example.

[Table 1]

[Table 2]

The sheets obtained in Examples 1 to 8 all had good surface appearance, soft texture, and good abrasion resistance. On the other hand, the sheet-like objects obtained in Comparative Examples 1 and 4 were poor in abrasion resistance, and the sheet-like objects obtained in Comparative Examples 2 to 5 were all poor in surface appearance. In addition, the feel of the sheets obtained in Comparative Examples 2, 3, and 5 was hard.

Industrial availability

The sheet obtained according to the present invention can be suitably used as an interior decoration having a very beautiful appearance as a surface material of furniture, chairs and wall materials, seats, ceilings and interior decorations in the vehicle interior of automobiles, trains and aircrafts, etc. Materials, shoe uppers, trims, etc. for shirts, jackets, casual shoes, sports shoes, men’s and women’s shoes, etc., bags, belts, wallets, etc., and clothing materials used for parts of them, wiping cloths, Industrial materials such as abrasive cloths and CD curtains.

Claims (6)

1. A method for manufacturing a sheet, characterized in that the following steps 1 to 5 are carried out sequentially, Step 1: dissolving polyvinyl alcohol with a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water to obtain an aqueous solution of polyvinyl alcohol with concentrations of methyl acetate, acetic acid and methanol below 50 ppm respectively; Step 2: Applying the polyvinyl alcohol aqueous solution to a fibrous base material mainly composed of microfiber-developing fibers, thereby imparting 0.1 to 50% by mass of the polyvinyl alcohol solution relative to the fiber mass contained in the fibrous base material. polyvinyl alcohol; Step 3: developing ultrafine fibers with an average single fiber diameter of 0.3 to 7 μm from a fibrous base material mainly composed of ultrafine fiber-displaying fibers; Step 4: imparting water-dispersible polyurethane to the fibrous base material mainly composed of microfibers to which polyvinyl alcohol has been imparted; Step 5: Removing polyvinyl alcohol from the fibrous base material mainly composed of microfibers to which water-dispersible polyurethane has been applied. 2 . The method for producing a sheet-like object according to claim 1 , wherein the concentrations of methyl acetate, acetic acid, and methanol in the polyvinyl alcohol aqueous solution are 0.1 to 50 ppm, respectively. 3. The manufacturing method of a sheet-shaped object according to claim 1 or 2, wherein the step of developing the ultrafine fibers is a step of treating in an alkaline aqueous solution. 4. The manufacturing method of a sheet-shaped article according to claim 1 or 2, comprising the steps of applying polyvinyl alcohol and heating at 80 to 170°C. 5. The manufacturing method of the sheet-like object according to claim 1 or 2, wherein the fibrous base material with the superfine fiber display type fiber as the main constituent is entangled with the fabric and/or braided fabric change. 6. A sheet, characterized in that the density of the sheet obtained by the method for producing a sheet according to any one of claims 1 to 5 is 0.2 to 0.7 g/cm ³ .