KR20150090122A - Sheet-shaped object and process for producing said sheet-shaped object - Google Patents

Abstract

An object of the present invention is to provide a method for producing a sheet product which achieves a fine appearance with napping and a soft feeling and has good abrasion resistance and is characterized by carrying out the following steps (1) to (5) do. (1) a step of dissolving polyvinyl alcohol having a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water to obtain a polyvinyl alcohol aqueous solution each having 50 ppm or less of methyl acetate, acetic acid and methanol, (2) (3) a step of adding 0.1 to 50% by mass of the polyvinyl alcohol to the fibrous substance of the fibrous substance based on the fibrous substance containing the expression-type fiber as a main component, (3) (4) a step of imparting an aqueous dispersion type polyurethane to the fibrous base material obtained in the step (3); (5) And removing the polyvinyl alcohol from the fibrous substrate obtained in the step (c).

Description

[0001] SHEET-SHAPED OBJECT AND PROCESS FOR PRODUCING SAID SHEET-SHAPED OBJECT [0002]

Disclosure of the Invention An object of the present invention is to provide a sheet product in which a water dispersible polyurethane is used as a binder resin to reduce the amount of an organic solvent used in a production process and to consider the environment, And a process for producing the sheet-like product.

Sheet products mainly comprising a fibrous base material and a polyurethane have excellent characteristics not found in natural leather and are widely used for various purposes. In particular, since the leather-like sheet product using the polyester-based fibrous base material is excellent in light fastness, its use in medicine, chair covers, automobile interior materials and the like has been widened every year.

In producing such a sheet product, the fibrous substrate is impregnated with an organic solvent solution of polyurethane, and then the obtained fibrous substrate is immersed in a non-solvent of polyurethane or a mixed solution of organic solvent / water to wet-coagulate the polyurethane Processes are generally employed. A water-miscible organic solvent such as N, N-dimethylformamide (hereinafter also referred to as " DMF ") or the like is used as the organic solvent which is a solvent of the polyurethane. For example, polyvinyl alcohol ) Was impregnated with the aqueous solution to obtain a fibrous sheet product. The fibrous sheet product was immersed in a polyurethane impregnation solution, and the polyurethane was wet-coagulated again in a 45% aqueous solution of DMF at 20 DEG C, There has been proposed a method for producing a sheet product by removing polyvinyl alcohol (see Patent Document 1). However, in general, since organic solvents are highly harmful to humans and the environment, there is a strong demand for a method that does not use organic solvents in the production of sheet-like products.

As a specific means for solving the problem, for example, a method of using a water-dispersible polyurethane in which polyurethane is dispersed in water is being studied instead of a conventional organic solvent-type polyurethane. However, there is a problem that the sheet product impregnated with a fibrous base material and impregnated with an aqueous dispersion type polyurethane has a hard texture. The main reason for this task is that the polyurethane strongly adheres to the fibers of the fibrous substrate. In order to solve such a problem, in order to partially inhibit the adhesion between the fiber and the polyurethane and to form a gap between the fiber and the polyurethane, as in the manufacturing process using the conventional organic solvent type polyurethane, A method has been proposed in which PVA is previously applied to a base material, and then polyurethane is applied, followed by removing the PVA (see Patent Document 2).

Here, since PVA is water-soluble, the PVA is dissolved and removed when water is added to the fibrous substrate after the PVA is added to the fibrous substrate. Therefore, in order to suppress dissolution and detachment of PVA in the water- , the following means are adopted in the step (i) of microfibers of fibers by an aqueous alkali solution and (ii) the step of impregnating aqueous dispersed polyurethane. In the impregnation step of the latter aqueous dispersion type polyurethane, the PVA having a degree of saponification of 98% and a degree of polymerization of 500 The use of PVA inhibits the dropping of PVA into water. However, as for the effect of addition of borax in the microfabrication process of fibers, it takes a long time to immerse the alkali in the aqueous alkali solution in order to make the fiber finer, so that even when borax is added to the alkali aqueous solution, the dissolution of PVA into water can be completely suppressed There is no. Since the degree of polymerization of the PVA is low in the impregnation step of the water-dispersible polyurethane, dissolution in water can not be completely inhibited and dropout to the aqueous dispersion type polyurethane solution can not be suppressed. As PVA is dissolved, the state of adhesion between the polyurethane and the fiber can not be stably controlled, and there is a problem that the feel of the sheet-like material becomes hard.

In addition, with respect to the problems in the above steps (i) and (ii), the PVA solubility in water is lowered by heating the nonwoven fabric sheet at a temperature of 150 to 195 DEG C while adding PVA having a degree of saponification of 90% (See Patent Document 3). If the temperature is too high or the heating time is too long, the PVA is insolubilized and it becomes difficult to redissolve the water. When the temperature is too high or the heating time is too long, Therefore, there has been a problem that it is difficult to stabilize an appropriate condition.

Japanese Patent Laid-Open No. 2002-30579 Japanese Patent Application Laid-Open No. 2003-096676 Japanese Patent No. 4644971

The present invention provides a method for producing a sheet-like product in which the use of an organic solvent in a production process is reduced and the environment is taken into account, and a method for producing a sheet- And a sheet product obtained by the method for producing the same.

That is, the method for producing a sheet product of the present invention is characterized in that the following steps 1 to 5 are carried out in order.

1. A process for producing a polyvinyl alcohol aqueous solution having a concentration of methyl acetate, acetic acid and methanol of 50 ppm or less by dissolving polyvinyl alcohol having a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water,

2. A process for producing a fibrous base material, comprising the steps of applying 0.1 to 50% by mass of the polyvinyl alcohol to the amount of fibers contained in the fibrous base material by applying the aqueous polyvinyl alcohol solution to the fibrous base material having the ultrafine fiber-

3. A process for producing microfine fibers having an average single fiber diameter of 0.3 to 7 占 퐉 from a fibrous base material containing microfine fiber-

4. A process for producing a water-dispersible polyurethane, comprising the steps of providing a water-dispersible polyurethane to a fibrous base material having microvoled fibers imparted with the polyvinyl alcohol as a main constituent,

5. A step of removing polyvinyl alcohol from a fibrous base material containing microfine fibers imparted with the water-dispersed polyurethane as a main constituent.

According to a preferred embodiment of the process for producing a sheet product of the present invention, it is a process for producing a polyvinyl alcohol aqueous solution having a concentration of methyl acetate, acetic acid and methanol of 0.1 to 50 ppm, respectively.

According to a preferred embodiment of the method for producing a sheet of the present invention, the step of expressing the microfine fibers is a step of treating with an alkali aqueous solution.

According to a preferred embodiment of the process for producing a sheet product of the present invention, it is a production process comprising the step of applying the polyvinyl alcohol and heating at 80 to 170 ° C.

According to a preferred embodiment of the method for producing a sheet-like product of the present invention, the fibrous base material containing the ultrafine fiber-forming fiber as a main component is integrally formed with a fabric and / or a knitted fabric.

It is also preferable that the density of the obtained sheet product is 0.2 to 0.7 g / cm 3.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a sheet product having a superior appearance and a soft feeling which can not be compatibly compatible with environmentally-friendly manufacturing processes, and which has good abrasion resistance.

The method for producing a sheet product of the present invention is characterized in that the following steps 1 to 5 are carried out in this order.

1. A process for producing a polyvinyl alcohol aqueous solution having a concentration of methyl acetate, acetic acid and methanol of 50 ppm or less by dissolving polyvinyl alcohol having a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water,

2. A process for producing a fibrous base material, comprising the steps of applying 0.1 to 50% by mass of the polyvinyl alcohol to the amount of fibers contained in the fibrous base material by applying the aqueous polyvinyl alcohol solution to the fibrous base material having the ultrafine fiber-

3. A process for producing microfine fibers having an average single fiber diameter of 0.3 to 7 占 퐉 from a fibrous base material containing microfine fiber-

4. A process for producing a water-dispersible polyurethane, comprising the steps of providing a water-dispersible polyurethane to a fibrous base material having microvoled fibers imparted with the polyvinyl alcohol as a main constituent,

5. A step of removing polyvinyl alcohol from a fibrous base material containing microfine fibers imparted with the water-dispersed polyurethane as a main constituent.

In the process for producing a sheet material of the present invention, it is important to carry out the steps 1 to 5 in this order. The present invention relates to a method for producing a microfine fiber-expressing fiber which is characterized in that microfine fibers are expressed from a microfine fiber-expressing fiber after imparting an aqueous solution of polyvinyl alcohol (also referred to as PVA) having a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 to a fibrous base material having microfine fiber- And then removing the PVA from the fibrous base material. Thereafter, a water-dispersible polyurethane solution is added to the fibrous base material containing the PVA-added microfine fibers as the main constituent component, PVA and the sea component, and the polyurethane partially grasps the microfine fibers partly. Thus, it is possible to express physical characteristics such as good abrasion resistance together with fine appearance and soft feeling.

Further, when a PVA aqueous solution is added to a fibrous base material and heated and dried, a so-called migration phenomenon occurs, in which PVA in water is concentrated due to the movement of water, so that a so-called migration phenomenon occurs and a large amount is adhered to the surface layer of the fibrous base material. So that it is in a state in which it is less attached. The water-dispersible polyurethane which is subsequently added by the migration of PVA is mainly attached to the inner layer of the fibrous base material. When the PVA is removed, the voids are greatly formed between the fiber and the polyurethane in the vicinity of the surface layer of the fibrous base material to which the PVA is adhered, and the appearance of the surface of the sheet material subjected to the napping process is uniformly loosened It becomes a splendid appearance.

On the other hand, when the deaeration treatment is carried out after removing the PVA, both of the pores caused by removing the PVA between the polyurethane and the microfine fibers and the pores caused by the debris of the sea component are generated, so that the microfine fibers are directly held by the polyurethane The area becomes smaller and the feeling of the sheet-like material becomes more flexible, but the physical properties such as abrasion resistance tend to deteriorate.

[First Step]

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

Methyl acetate, acetic acid, and methanol are substances produced during the process of increasing the degree of saponification from polyvinyl acetate, which is a precursor of PVA synthesis, and are also produced by decomposition of residual polyvinyl acetate that is not sufficiently saponified. Since methyl acetate, acetic acid, and methanol have concentrations of methyl acetate, acetic acid, and methanol of 50 ppm or less in the aqueous PVA solution, the hydrogen bonds between the PVA molecules are easily formed during heating and drying, and water (including hot water) , The solubility of PVA in an aqueous alkaline solution can be suppressed. Further, in view of easy formation of hydrogen bonds between PVA molecules, the thermal drying temperature can be set at 80 to 140 占 폚, which is comparatively low, so that pyrolysis of PVA can be suppressed. The concentrations of methyl acetate, acetic acid, and methanol in the PVA aqueous solution are more preferably 0.1 to 50 ppm, and methyl acetate, acetic acid, and methanol are present in trace amounts, respectively, so that they are weakly hydrogen bonded to the PVA molecules, Thereby easily forming a hydrogen bond between PVA molecules. If the concentrations of methyl acetate, acetic acid, and methanol are too high, on the contrary, they inhibit the formation of hydrogen bonds between PVA molecules. Therefore, the more preferable concentration is 0.3 to 40 ppm, more preferably 5 to 40 ppm.

The concentrations of methyl acetate, acetic acid and methanol in the PVA aqueous solution are analyzed as follows. Add 1 g of PVA aqueous solution to a 24 mL heating tube and heat at 90 ° C for 1 hour. From the heating tube, 0.1 mL of gas generated from the gas-tight syringe is sampled and introduced into a GC / MS (mass spectrometer connected directly to a gas chromatograph) for analysis.

In order to lower the concentrations of methyl acetate, acetic acid and methanol in the PVA aqueous solution, PVA having a small amount of methyl acetate, acetic acid and methanol generated during the heating of the PVA itself before the aqueous solution is used, or PVA It is sufficient to increase the heating time at the heating temperature for dissolving in water. With respect to the former, the higher the degree of saponification, the smaller the amount of methyl acetate, acetic acid, and methanol generated. Therefore, it is preferable to use PVA having a degree of saponification of 98% or higher. In the latter case, the temperature is preferably from 80 to 100 ° C, since methyl acetate, acetic acid and methanol can not be sufficiently removed when the temperature for raising the temperature is too low. If the heating time is too short, methyl acetate, acetic acid and methanol are sufficiently removed In view of the inability to do so, an hour or more is preferable. In addition, methyl acetate, acetic acid, and methanol may be completely removed from the PVA aqueous solution.

In the form of the present invention, the PVA imparted to the fibrous substrate has a saponification degree of 98% or more and a degree of polymerization of 800 to 3500. By setting the degree of saponification of the PVA to 98% or more, it is possible to prevent the PVA from dissolving in the water-dispersible polyurethane liquid when imparting the water-dispersible polyurethane. When the PVA is dissolved in the aqueous dispersion type polyurethane liquid, not only an effect sufficient to protect the surface of the microfine fibers constituting the nannies can not be obtained, but also when the aqueous dispersion type polyurethane solution in which PVA is dissolved is added to the fibrous substrate, PVA is introduced into the urethane, and it becomes difficult to remove the PVA thereafter. Therefore, the state of adhesion between the polyurethane and the fiber can not be stably controlled, and the feel is hardened.

In addition, the solubility of PVA in water varies depending on the degree of polymerization, and the smaller the degree of polymerization of PVA, the more soluble PVA is dissolved in the water-dispersible polyurethane liquid when the water-dispersible polyurethane is added. The higher the degree of polymerization of the PVA, the higher the viscosity of the PVA aqueous solution, and the higher the degree of PVA polymerization, the better the degree of polymerization of PVA is from 1000 to 3000, 1200 to 2500.

In the present invention, the PVA preferably has a viscosity of 10 to 70 mPa · s at 20 ° C in a 4 mass% aqueous solution. Since the PVA has a viscosity within this range, a proper migration structure can be obtained in the fibrous substrate during drying, and a balance of physical properties such as flexibility, surface appearance and abrasion resistance of the sheet can be obtained. By setting the viscosity to 10 mPa · s or more, and more preferably to 15 mPa · s or more, an extreme migration structure can be suppressed. On the other hand, PVA can be easily impregnated into the fibrous substrate by setting the viscosity to 70 mPa · s or less, more preferably 50 mPa · s or less, and furthermore preferably 40 mPa · s or less.

In the present invention, the glass transition temperature (Tg) of PVA is preferably 70 to 100 캜. By setting the glass transition temperature of the PVA to 70 deg. C or higher, more preferably 75 deg. 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 . Further, by setting the glass transition temperature to 100 占 폚 or lower, more preferably 95 占 폚 or lower, it is possible to prevent the handling of the fibrous substrate from becoming too hard.

In the present invention, the melting point of PVA is preferably 200 to 250 ° C. By setting the melting point of PVA to 200 DEG C or higher, more preferably 210 DEG 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. Further, by setting the melting point of the PVA to 250 DEG C or less, more preferably 240 DEG C or less, the handling of the fibrous base material can be prevented from being deteriorated by being too hard.

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, deterioration of the surface appearance of the sheet can be suppressed by suppressing the dimensional change during handling. By setting the tensile strength of the PVA film to not more than 800 kg / cm 2, more preferably not more than 750 kg / cm 2, the PVA-imparted sheet is not excessively hardened and occurrence of buckling wrinkles or the like at the time of handling can be suppressed. The term "tensile strength" as used herein means a value obtained by measuring a PVA film having a thickness of 100 μm in an atmosphere at a temperature of 20 ° C. and a humidity of 65%.

[Second Step]

Next, a step of imparting the PVA in an amount of 0.1 to 50 mass% with respect to the amount of fibers contained in the fibrous base material by applying a PVA aqueous solution to the fibrous base material containing the ultrafine fiber-forming fiber as the second component is described .

The fibrous base material of the present invention mainly comprises microfine fiber-forming fibers. By using the ultrafine fiber-expressible fiber, the fiber is subjected to the ultrafine fiber-finishing step, whereby the fiber can be made finer and the appearance of a fine surface can be obtained.

In a preferred form of the present invention, the average single fiber diameter of the microfine fibers obtained from the microfine fiber-forming fibers through the fiber microfabrication process is 0.3 to 7 mu m. By setting the average single fiber diameter to be not more than 7 mu m, more preferably not more than 6 mu m, and further preferably not more than 5 mu m, it is possible to obtain a sheet having excellent flexibility and a good mood. On the other hand, by setting the average single fiber diameter to 0.3 mu m or more, more preferably 0.7 mu m or more, and further preferably 1 mu m or more, excellent dispersibility of bundle fibers at the time of napping treatment such as coloring after dyeing and grinding with sand paper or the like is excellent And the ease of loosening is also excellent.

As the microfine fiber-expressible fiber, there are (a) two component thermoplastic resins having different solvent solubility as the sea component and the island component, and the sea component is dissolved and removed by using a solvent or the like to produce a sea- Or (b) peelable composite fibers in which two component thermoplastic resins are alternately arranged radially or multilayer on the fiber cross section, and each component is peeled and divided into ultrafine fibers. Among them, the sea-island type fiber is preferably used from the standpoint of the flexibility and feel of the sheet-shaped water because it is possible to impart a proper gap between island components, that is, microfine fibers, by removing sea components.

Examples of the sea-island type fiber include a sea-island composite fiber in which sea components and island components are mutually arranged and radiated using a sea-island type composite seam; And mixed yarn fibers in which two components of sea component and island component are mixed and radiated. A sea-island composite fiber is preferably used in that ultrafine fibers having uniform fineness can be obtained, and ultrafine fibers having a sufficient length can be obtained and also contribute to the strength of the sheet.

The island component of the sea-island fiber is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate and polylactic acid; Polyamides such as 6-nylon and 66-nylon; acryl; Polyethylene; Polypropylene; And thermoplastic resin melt-spinnable such as thermoplastic cellulose or the like can be used. Among them, polyester fibers are preferably used from the viewpoints of strength, dimensional stability and light fastness. From the viewpoint of environmental consideration, it is preferable that the fibers are obtained from recycled raw materials and plant-derived raw materials. Further, the fibrous substrate may be formed by mixing fibers of different materials.

The sea component of the sea-island type fibers is not particularly limited, and examples thereof include polyethylene; Polypropylene; polystyrene; Copolyesters and polylactic acid obtained by copolymerizing sodium sulfoisophthalate or polyethylene glycol; PVA and the like can be used. Among them, from the viewpoint of environmental consideration, copolyester or polylactic acid copolymerized with degradable alkali-decomposable sodium polyphosphate sodium or polyethylene glycol without using an organic solvent is preferable, and a thermally water-soluble PVA is preferable.

The cross-sectional shape of the fibers constituting the fibrous base material is not particularly limited and may be a circular cross section, but polygonal shapes such as ellipse, flattened and triangular shapes, and cross-sectional shapes such as a fan shape and a cross shape may be employed.

In the present invention, the fibers constituting the fibrous substrate preferably have an average short fiber diameter of 0.3 to 20 mu m. On the other hand, as the average single fiber diameter becomes larger, the coloring properties after dyeing and the grinding with sandpaper or the like are more dispersed and loosened at the time of napping treatment, More preferably 0.7 to 15 占 퐉, and particularly preferably 1 to 7 占 퐉, from the viewpoint of ease of use.

The fibrous substrate of the present invention may be in the form of a woven fabric, a knitted fabric, or a nonwoven fabric. Among them, a nonwoven fabric is preferably used because the surface appearance of the sheet is good when the surface is brushed.

The nonwoven fabric may be either a single-fiber nonwoven fabric or a long-fiber nonwoven fabric. However, the long-fiber nonwoven fabric has fewer fibers oriented toward the thickness direction of the sheet-like material as the nap- A short-fiber nonwoven fabric is preferably used because it tends to lose appearance.

The fiber length of the short fibers in the single-fiber nonwoven fabric is preferably 25 to 90 mm. By setting the fiber length to 25 mm or more, it is possible to obtain a sheet product having excellent abrasion resistance by locking. By setting the fiber length to 90 mm or less, it is possible to obtain a sheet product excellent in texture and durability. The fiber length is more preferably 30 to 80 mm.

As a method for locking the fibers or fiber bundles of the nonwoven fabric, needle punches or water jet punches can be employed.

In the present invention, when the fibrous substrate containing microfine fibers is a nonwoven fabric, the nonwoven fabric preferably has a structure in which microfine fibers (microfine fiber bundles) are locked together. The superfine fibers are locked in a bundle state to improve the strength of the sheet. This type of nonwoven fabric can be obtained by preliminarily laminating the microfine fiber-forming fibers together and then developing the microfine fibers.

When the microfine fibers or microfine fiber bundles thereof constitute a nonwoven fabric, they may be integrated with a fabric or a knitted fabric in order to improve the strength of the nonwoven fabric. For example, in the case of a fabric, plain weave, twill weave, and weave weave can be mentioned, and plain weave is preferably used in terms of cost. In the case of the knitted fabric, there may be mentioned circular knit, tricot, and Russell. The average single fiber diameter of the fibers constituting the fabric or the knitted fabric is preferably 0.3 to 20 mu m.

In a preferred embodiment of the present invention, when the fabric and / or the knitted fabric are integrally formed into a single piece of the fibrous base material having microfine fiber-forming fibers as main components, PVA is imparted, And / or the area for directly holding the knitted fabric is decreased, and the feeling of the sheet-like material is softened. In particular, when the fabric and / or the knitted fabric are composed of fibers that are not microfine fiber- .

The amount of PVA to be imparted to the fibrous substrate is from 0.1 to 50 mass%, preferably from 1 to 45 mass%, based on the fibrous amount of the fibrous substrate. When the amount of PVA applied is 0.1% by mass or more, a sheet product having excellent flexibility and feeling can be obtained. When the amount of PVA is 50% by mass or less, a sheet product having good workability and good physical properties such as abrasion resistance is obtained Loses.

In the present invention, the method for applying PVA to the fibrous base material is not particularly limited and various methods commonly used in the art can be employed. However, a method of dissolving PVA in water, impregnating the fibrous base material and heating and drying From the viewpoint of homogeneously imparting them. If the temperature is too low, the drying time is long. If the temperature is too high, the PVA is insolubilized and can not be dissolved and removed. Therefore, the drying is preferably performed at 80 to 140 ° C, And preferably 110 to 130 ° C. The drying time is usually 1 to 20 minutes, preferably 1 to 10 minutes, and more preferably 1 to 5 minutes from the viewpoint of workability. Further, in order to further insolubilize the PVA, a heat treatment may be performed after drying. The preferred temperature for the heat treatment is 80 to 170 占 폚. Since the insolubilization of the PVA and the thermal degradation of the PVA proceed simultaneously by the heat treatment, the more preferable temperature is 80 to 140 占 폚.

[Third Step]

Next, the step of expressing the ultrafine fibers having an average single fiber diameter of 0.3 to 7 mu m from the fibrous base material containing the ultrafine fiber-forming fibers as the third component will be described.

The fiber fineness treatment (de-aeration treatment) of the fibrous base material having the ultrafine fiber-expressing fiber as a main component can be performed by immersing the fibrous base material in a solvent and immersing it in a liquid. When the ultrafine fiber-expressible fiber is a sea-island fiber, when the sea component is polyethylene, polypropylene or polystyrene, an organic solvent such as toluene or trichlorethylene is used, and when the sea component is a copolymerized polyester or polylactic acid An aqueous alkali solution such as sodium hydroxide may be used. In the case where the sea component is PVA, hot water can be used. From the viewpoint of environmental consideration of the process, an alkali aqueous solution such as sodium hydroxide or a deaeration treatment by hot water is preferable.

[Fourth Step]

Next, the step of imparting the water dispersible polyurethane to the fibrous base material having the PVA-imparted ultrafine fibers as the main constituent components in the fourth step will be described.

(II) a polyurethane having a hydrophilic structure in the molecular structure of polyurethane, and having no hydrophilic structure even in the presence of a surfactant, the water-dispersible polyurethane is preferably a water-insoluble polyurethane which is dispersed and stabilized in water by forcibly using (I) Emulsified polyurethane which is dispersed and stabilized in the polyurethane resin, but any of them may be used in the present invention.

The method of imparting the water-dispersible polyurethane to the fibrous base material is not particularly limited, but is preferably a method in which a water-dispersible polyurethane liquid is impregnated and coated on the fibrous base material, and a method of heating and drying after coagulation is uniformly given .

The concentration of the aqueous dispersion type polyurethane solution (the content of polyurethane relative to the aqueous dispersion type polyurethane solution) is preferably from 10 to 50 mass%, more preferably from 15 to 40 mass%, from the viewpoint of the storage stability of the aqueous dispersion type polyurethane solution Mass%.

The water-dispersible polyurethane liquid used in the present invention 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 formability. However, The content of the organic solvent is preferably 1% by mass or less.

In addition, as the aqueous polyurethane liquid used in the present invention, it is preferable that the aqueous polyurethane liquid has heat-coagulability. By using the water-dispersible polyurethane liquid having heat-settability, the polyurethane can be uniformly applied in the thickness direction of the fibrous substrate.

In the present invention, the term "thermal coagulation" means that the fluidity of the polyurethane liquid decreases and coagulates when the polyurethane liquid reaches a certain temperature (thermal coagulation temperature) when it is heated. In the production of the polyurethane-containing sheet, the polyurethane solution is applied to the fibrous base material by applying the polyurethane liquid to the fibrous base material and then coagulating by dry coagulation, wet heat coagulation, wet coagulation or a combination thereof and drying. As a method of coagulating the aqueous dispersion type polyurethane liquid which does not exhibit heat-solidifying property, dry coagulation is realistic in industrial production. However, in this case, migration phenomenon in which polyurethane is concentrated on the surface layer of the fibrous base material occurs, The texture of the product tends to be hardened. In this case, migration can be prevented by adjusting the viscosity of the aqueous dispersion type polyurethane liquid with the thickener. Also in the case of an aqueous dispersion type polyurethane liquid exhibiting thermal coagulation property, migration can be prevented by adding a thickening agent and performing dry coagulation.

The thermal coagulation temperature of the aqueous dispersion type polyurethane liquid is preferably 40 to 90 占 폚. When the thermal coagulation temperature is 40 占 폚 or higher, the stability of the polyurethane solution during storage is improved, and adhesion of polyurethane to the machine during operation can be suppressed. Further, by setting the heat-coagulation temperature to 90 占 폚 or less, the migration phenomenon of polyurethane to the surface layer of the fibrous base material can be suppressed.

In one aspect of the present invention, a thermosetting coagulant may be added in a timely manner in order to set the thermosetting coagulation temperature as described above. Examples of the heat coagulant include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate and calcium chloride; And radical reaction initiators such as sodium persulfate, potassium persulfate, ammonium persulfate, azobisisobutyronitrile and benzoyl peroxide.

In a preferred form of the present invention, the polyurethane liquid can be impregnated and coated on the fibrous base material, and the polyurethane can be solidified by dry solidification, wet heat solidification, wet solidification, or a combination thereof.

The temperature of the wet heat coagulation is preferably not lower than the heat coagulation temperature of the polyurethane, and is preferably from 40 to 200 캜. By setting the temperature for moist heat coagulation to 40 DEG C or higher, more preferably 80 DEG C or higher, the time until solidification of the polyurethane can be shortened to further suppress the migration phenomenon. On the other hand, by setting the temperature of wet heat coagulation to 200 DEG C or lower, more preferably 160 DEG C or lower, thermal degradation of polyurethane or PVA can be prevented.

The temperature of the wet coagulation is preferably not less than the heat coagulation temperature of the polyurethane, and is preferably 40 to 100 캜. By setting the temperature of the wet coagulation in the hot water to 40 DEG C or higher, more preferably 80 DEG C or higher, the time until solidification of the polyurethane can be shortened to further suppress the migration phenomenon.

The dry coagulation temperature and the drying temperature are preferably 80 to 140 ° C. By setting the dry coagulation temperature and the drying temperature at 80 DEG C or higher, more preferably 90 DEG C or higher, productivity is excellent. On the other hand, by setting the dry coagulation temperature and the drying temperature at 140 占 폚 or lower, more preferably 130 占 폚 or lower, it is possible to prevent thermal degradation of polyurethane or PVA.

In the present invention, the polyurethane may be coagulated and then heat treated. The heat treatment reduces the interface between the polyurethane molecules, resulting in a more rigid polyurethane. In a more preferred embodiment, it is preferable to perform the heat treatment after removing the PVA from the sheet provided with the water-dispersed polyurethane. The temperature of the heat treatment is preferably 80 to 170 占 폚.

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

The polymer diol is not particularly limited. For example, a polycarbonate-based, polyester-based, polyether-based, silicone-based or fluorine-based diol may be employed, and a copolymer obtained by combining these may be used. From the standpoint of hydrolysis resistance, polycarbonate-based and polyether-based diols are preferably used. From the viewpoint of light resistance and heat resistance, a polycarbonate-based resin or a polyester-based resin is preferably used. From the standpoint of balance of the hydrolysis resistance, heat resistance and light resistance, polycarbonate-series and polyester-series diols are more preferable, and polycarbonate-series diols are particularly preferably used.

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

Examples of the alkylene glycol include, but are not limited to, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9- -Decandiol, and the like, and linear alkylene glycols such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, Alicyclic diols such as 1,4-cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylol propane and pentaerythritol. A polycarbonate diol obtained from a single alkylene glycol or a copolymerized polycarbonate diol obtained from two or more alkylene glycols may be used.

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

Examples of the low molecular weight polyol include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2- , 3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethyleneglycol, triethyleneglycol, dipropyleneglycol, tripropyleneglycol, cyclohexane- 1,4-diol, and cyclohexane-1,4-dimethanol. Adducts in which various alkylene oxides are added to bisphenol A can also be used.

Examples of the polybasic acid include, but are not limited to, succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, , Terephthalic acid, and hexahydroisophthalic acid.

Examples of the polyether diols include, but are not limited to, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymerized diols obtained by combining them.

The number average molecular weight of the polymer diol used in the present invention is preferably 500 to 4000. By setting the number average molecular weight to 500 or more, more preferably 1,500 or more, it is possible to prevent the feeling from becoming hard. By setting the number average molecular weight to 4,000 or less, more preferably 3,000 or less, the strength as a polyurethane can be maintained.

Examples of the organic diisocyanate include, but are not limited to, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and xylylene isocyanate, diphenylmethane diisocyanate and tolylene diisocyanate And aromatic diisocyanates such as diisocyanate, diisocyanate, and diisocyanate. These diisocyanates may be used in combination. Among them, aliphatic diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate are preferably used from the viewpoint of light resistance.

The chain extender is not particularly limited, but amine chain extender such as ethylenediamine and methylenebisaniline, and diol chain extender such as ethylene glycol can be used. Further, a polyamine obtained by reacting a polyisocyanate with water may be used as a chain extender.

The polyurethane may be used in combination with a crosslinking agent for the purpose of improving the water resistance, abrasion resistance and hydrolysis resistance, if desired. The crosslinking agent may be an external crosslinking agent added to the polyurethane as a third component, or may be an internal crosslinking agent which introduces a reaction point in the crosslinked structure in advance in the polyurethane molecular structure. In the present invention, it is preferable to use an internal cross-linking agent because it is possible to more uniformly form cross-linking points within the molecular structure of the polyurethane and reduce the decrease in flexibility.

As the crosslinking agent, a compound having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin and a silanol group can be used. However, when the crosslinking proceeds excessively, the polyurethane tends to be cured and the feeling of the sheet-like water tends to be hardened. Therefore, from the viewpoint of balance of reactivity and flexibility, those having a silanol group are preferably used.

The polyurethane used in the present invention preferably has a hydrophilic group in its molecular structure. By having a hydrophilic group in the molecular structure, it is possible to improve dispersion and stability as an aqueous polyurethane.

Examples of the hydrophilic group include a cationic group such as a quaternary amine salt, an anionic group such as a sulfonate or a carboxylate, a nonionic group such as polyethylene glycol, a combination of a cationic group and a nonionic group, A hydrophilic group can be employed. Among them, a non-ionic hydrophilic group free from yellowing due to light or a harmful effect due to a neutralizing agent is particularly preferably used.

In the case of an anionic type hydrophilic group, a neutralizing agent is required. For example, when the neutralizing agent is a tertiary amine such as ammonia, triethylamine, triethanolamine, triisopropanolamine, trimethylamine and dimethylethanolamine, Amines are generated and volatilized by the heat at the time of drying, and are released to the outside of the system. Therefore, in order to suppress the atmospheric release or the deterioration of the working environment, it is necessary to introduce a device for recovering the volatilized amine. It is also conceivable that when the amine is not volatilized by heating and remains in the sheet product, which is the final product, the amine is discharged to the environment at the time of incineration of the product. On the other hand, in the case of a nonionic type hydrophilic group, since a neutralizing agent is not used, there is no need to introduce an amine recovery apparatus, and there is no concern of residual amine in the sheet product.

When the neutralizing agent of the anionic hydrophilic group is an alkali metal or an alkaline earth metal hydroxide such as sodium hydroxide, potassium hydroxide or calcium hydroxide, the polyurethane portion is alkaline when it is wetted with water. In the case of a nonionic type hydrophilic group, It is not necessary to worry about deterioration due to hydrolysis of the polyurethane.

The water dispersible polyurethane used in the present invention may contain various additives, for example, pigments such as carbon black, flame retardants such as phosphorus, halogen, silicone and inorganic, antioxidants such as phenol, Ultraviolet absorbers such as triazole, benzophenone, salicylate, cyanoacrylate and oxalic acid anilide, light stabilizers such as hindered amines and benzoates, iodine stabilizers such as polycarbodiimides, , A filler such as a plasticizer, an antistatic agent, a surfactant, a softener, a water repellent, a coagulation adjusting agent, a viscosity adjusting agent, a dye, a preservative, an antibacterial agent, a deodorant, a cellulose particle or a microballoon, and an inorganic particle such as silica or titanium oxide have. In order to further increase the pores between the fibers and the polyurethane, inorganic bases such as sodium hydrogen carbonate and organic foams such as 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] ≪ / RTI >

The content ratio of the polyurethane to the fibrous base material containing the ultrafine fibers of the present invention as a main component is preferably 1 to 80% by mass. By setting the ratio of the polyurethane to 1% by mass or more, more preferably 5% by mass or more, it is possible to prevent the fiber from falling off while obtaining the sheet strength. Further, by setting the blending ratio of the polyurethane to 80 mass% or less, more preferably 70 mass% or less, it is possible to prevent the feeling of hardness from becoming hard and to obtain a satisfactory nappy product.

[Step 5]

Next, the step of removing PVA from the fibrous base material containing the ultrafine fibers imparted with the PVA and the water-dispersible polyurethane as the fifth step will be described.

In a preferred embodiment of the present invention, PVA is removed from the fibrous base material after polyurethane is applied to obtain a flexible sheet product. The method of removing PVA is not particularly limited, but it is a preferred form to dissolve and remove PVA by immersing the sheet in, for example, hot water at 60 to 100 캜 and, if necessary, mangling by mangling or the like.

In the method for producing a sheet-like product of the present invention, after the water-dispersible polyurethane is added to the fibrous base material to which at least PVA is added, it may include a step of half-cutting in the thickness direction. In the process of applying PVA, the PVA is attached to the surface layer of the fibrous base material by migration and the amount of PVA adhered to the inner layer is small. Thereafter, water dispersion type polyurethane is added and then divided in the thickness direction, whereby a watery polyurethane is adhered to a side having a larger PVA adhering amount and a sheet material having a structure in which water dispersed polyurethane is adhered to a side having a smaller PVA adhering amount is obtained Loses. In the case where the surface on which a large amount of PVA is attached (the surface with little water-dispersed polyurethane adherence) is used as the mouth surface of the sheet-like material, since PVA is applied, a large gap is formed between the polyurethane and the microfine fibers constituting the nap , A degree of freedom is imparted to the fibers constituting the nannies, and the surface of the nannies is softened to give a good appearance and a smooth touch. On the contrary, when the surface on which the PVA is little attached (surface with water-dispersed polyurethane adhesion) is used as the mouth surface of the sheet-like material, the fibers constituting the napping are firmly gripped on the polyurethane so that the napping length is short, Good appearance quality can be obtained, and the wear resistance is further improved. Further, by including the step of half-cutting in the thickness direction of the sheet, the production efficiency can be improved.

In the present invention, at least one surface of the sheet-like material may be brushed to form napping on the surface. The method of forming the nannies is not particularly limited, and various methods commonly used in the art can be used, such as buffing with sand paper or the like. It is preferable that the nap length is 0.2 to 1 mm from the viewpoint that if the nap length is too short, a fine appearance is difficult to obtain and if it is excessively long, peeling tends to occur easily.

In one embodiment of the present invention, silicon or the like may be imparted to the sheet material as a lubricant before brushed processing. By imparting a lubricant, it is possible to easily grind by surface grinding, and the surface quality is improved, which is preferable. Further, an antistatic agent may be applied before the brushed treatment, or an antistatic agent is added, which is a preferable form because grinding generated from the sheet by grinding becomes difficult to deposit on the sandpaper.

In one aspect of the invention, the sheet product can be dyed. As the dyeing method, various methods commonly used in the art can be employed, but a method using a liquid dyeing machine is preferred in that the sheet product can be softened by imparting a nonwoven effect simultaneously with the dyeing of the sheet.

The dyeing temperature varies depending on the type of fiber, but is preferably 80 to 150 ° C. By setting the dyeing temperature at 80 DEG C or higher, more preferably 110 DEG C or higher, it is possible to efficiently perform dyeing with fibers. On the other hand, by setting the dyeing temperature at 150 占 폚 or lower, more preferably 130 占 폚 or lower, deterioration of the polyurethane can be prevented.

The dye to be used in the present invention may be selected in accordance with the kind of fiber constituting the fibrous base material, and is not particularly limited. For example, if polyester fiber is used, a disperse dye can be used. Gold-containing dyes can be used, and combinations thereof can be used. In the case of dyeing with a disperse dye, reduction washing may be performed after dyeing.

It is also a preferable form to use a dyeing aid in dyeing. By using a dyeing auxiliary, uniformity and reproducibility of dyeing can be improved. After the dyeing and the passivation or dyeing, a finishing agent treatment using, for example, a softening agent such as silicone, an antistatic agent, a water repellent agent, a flame retardant agent, an anti-photographic agent and an antibacterial agent can be carried out.

The density of the sheet of the present invention thus obtained is preferably 0.2 to 0.7 g / cm 3. By setting the density to 0.2 g / cm3 or more, more preferably 0.3 g / cm3 or more, the surface appearance is dense and the durability can be enhanced. On the other hand, by setting the density to 0.7 g / cm3 or less, more preferably 0.6 g / cm3 or less, it is possible to prevent the feel of the sheet-like material from becoming hard.

Example

Next, the method for producing the sheet material of the present invention will be described in more detail by way of Examples, but the present invention is not limited to these Examples, and many modifications may be made within the technical scope of the present invention. It is possible by someone with knowledge.

[Assessment Methods]

(1) Organic solvent concentration of PVA aqueous solution

1 g of PVA aqueous solution was added to a 24 mL heating tube and heated at 90 캜 for 1 hour. 0.1 milliliter of the generated gas was taken from a heating tube into a gas tight syringe and introduced into GC / MS to analyze the concentration of methyl acetate, acetic acid and methanol. In addition, the detection limit of GC / MS is less than 0.1 ppm.

(2) Viscosity of aqueous PVA solution

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

(3) The tensile strength of PVA

The 10 mass% PVA aqueous dispersion was placed in a tray made of polyethylene having a length of 5 cm, a width of 10 cm and a depth of 1 cm, air-dried at 25 ° C for 8 hours, and heat-treated at 120 ° C for 2 hours To obtain a PVA dry film having a thickness of 100 mu m. With respect to this PVA dry film, the tensile strength was measured by a tensile tester in accordance with Method A (strip method) described in 8.14.1 of JIS L1096 (2010).

(4) Average short 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 the sheet surface at a magnification of 2000 times, randomly selecting 100 fibers, measuring the monofilament diameter and calculating an average value.

In the case where the fibers constituting the fibrous base material or the sheet material have a deformed cross-section, the diameter of the outer circumferential circle of the modified cross-section is calculated as the short fiber diameter. Further, in the case where the circular cross-section and the modified cross-section are mixed, the case in which the monofilament diameters are largely different are mixed, and the number of sampling according to the ratio of the number existing is selected to be 100 in total. However, when a reinforcing fabric or knitted fabric is inserted into the fibrous substrate, the fibers of the reinforcing fabric or the knitted fabric are excluded from the object of sampling in the measurement of the average single fiber diameter.

(5) Sliding degree of sheet water

A test piece of 2 cm x 15 cm in each of the longitudinal direction and the transverse direction was prepared on the basis of the method A (45 ° cantilever method) described in JIS L1096 (2010) 8.21.1 and placed on a horizontal table having an inclined surface of 45 ° , And the position of the other end when the center point of one end of the test piece was in contact with the inclined surface was read by the scale. The lattice constant is expressed by the length (mm) in which the test piece travels. An average value of the moving lengths of the five test pieces was obtained, and a lecture was made.

(6) Surface appearance of the sheet

The appearance of the surface of the sheet was evaluated by visual and sensory evaluation in five steps as follows, with a total of 20 persons, each of 10 adult male and 10 female adults with good health status, and the most frequent evaluation was made as the surface appearance . The surface appearance was evaluated as good from grade 3 to grade 5.

Grade 5: There are uniform napping of fibers, good fiber dispersion, and good appearance.

Level 4: Evaluation between level 5 and level 3.

Grade 3: There are some poorly dispersed fibers, but there are nails on the fibers and appearance is good at first.

Level 2: Evaluation between level 3 and level 1.

Grade 1: Overall, the dispersion of the fiber is very bad, or the napping of the fiber is long, and the appearance is poor.

(7) Evaluation of abrasion resistance of sheet

Nylon fibers having a diameter of 0.4 mm and containing nylon 6 were cut in a length of 11 mm perpendicularly to the longitudinal direction of the fibers to form a bundle of 100 bundles each consisting of 97 bundles each in a circle having a diameter of 110 mm One in the center, six in the circle of 17 mm in diameter, 13 in the circle of 37 mm in diameter, 19 in the circle of 55 mm in diameter, 26 in the circle of 74 mm in diameter, 32 in the circle of 90 mm in diameter, (Diameter: 45 mm) at a rotation speed of 65 rpm and a rotation frequency of 50 times by using a circular brush (9700 nylon yarns) arranged at intervals of 8 pounds (about 3629 g) Mm, and the change in mass of the sample before and after the abrasion was measured. The abrasion loss (mg), which is an average value of changes in mass of 5 samples, was taken as abrasion resistance.

[Example 1]

(Preparation of aqueous PVA solution)

PVA having a degree of saponification of 99% and a degree of polymerization of 1400 (NM-14 manufactured by Nippon Kosei Kagaku K.K.) was added to water at 25 占 폚, and after the temperature was raised to 90 占 폚, 90 占 폚 was maintained while stirring for 2 hours, % Aqueous solution to obtain a 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.

(Nonwoven fabric for fibrous substrate)

Polyethylene terephthalate copolymerized with 8 mol% sodium 5-sulfoisophthalate was used as the sea component, polyethylene terephthalate was used as the island component, and at a compounding ratio of 45% by mass of an ocean component and 55% by mass of an island component, A sea-island complex fiber having an island number of 36 degrees / filament and an average single fiber diameter of 17 mu m was obtained. The obtained sea-island composite fibers were cut into a staple with a fiber length of 51 mm to form a fibrous web through a card and a cross wrapper, and the fibrous web was formed into a nonwoven fabric by needle punching. The thus obtained nonwoven fabric was dipped in a bath at a temperature of 98 占 폚 for 2 minutes to shrink and dried at a temperature of 100 占 폚 for 5 minutes to obtain a nonwoven fabric for fibrous substrate.

(Application of PVA)

The above-mentioned nonwoven fabric for fibrous substrate was impregnated with the PVA aqueous solution and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having a PVA adhered amount of 30% by mass to the amount of fibrous nonwoven fabric.

(Microfiber (de-aeration))

The PVA-imparted sheet was immersed in an aqueous solution of sodium hydroxide having a concentration of 10 g / liter heated to a temperature of 95 캜 and treated for 30 minutes to obtain a deasphalted sheet from which marine components of sea-island complex fibers were removed. The average short fiber diameter on the surface of the deasphalted sheet was 3 mu m.

(Preparation of polyurethane liquid)

(APS) as a heat coagulating agent was added to 100 parts by mass of a solid content of a polycarbonate-based self-emulsifiable polyurethane liquid to which polyhexamethylene carbonate was applied to a polyol and dicyclohexylmethane diisocyanate was applied to the isocyanate, 2 parts by mass was added, and the whole was made up to 20% by mass of solid content with water to obtain an aqueous dispersion type polyurethane solution. The thermal coagulation temperature was 72 ° C.

(Impartation of polyurethane)

The above-described PVA-applied deaerated sheet was impregnated with the above-mentioned polycarbonate-based polyurethane solution, treated for 5 minutes under a moist heat atmosphere at a temperature of 100 캜, then hot-air dried at a drying temperature of 120 캜 for 5 minutes, And subjected to dry heat treatment at a temperature of 140 캜 for 2 minutes to obtain a sheet to which polyurethane was applied so that the amount of adhered polyurethane to the amount of fibers in the nonwoven fabric was 30% by mass.

(Removal of PVA)

The sheet provided with the polyurethane described above was immersed in water heated to 95 占 폚 and treated for 10 minutes to obtain a sheet from which the applied PVA was removed.

(Half, brushed, dyeing, reduction washing)

The sheet from which the PVA was removed was cut in the thickness direction and the surface opposite to the half surface was brushed by grinding using an endless sandpaper of 240 mesh and then dyed with a disperse dye using a circular dyeing machine and subjected to reduction washing To obtain a sheet product. The sheet surface thus obtained had a good surface appearance, a soft texture, and good wear resistance.

[Example 2]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate was obtained in the same manner as in Example 1.

(Application of PVA)

The same amount of PVA as in Example 1 was used and the squeezing after impregnation was adjusted to change the amount of PVA adhered. The amount of PVA adhered to the fibrous substance-based nonwoven fabric was 20% Was obtained.

(Microfiber (de-aeration))

A deaerated sheet was obtained in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The aqueous dispersion type polyurethane solution was obtained in the same manner as in Example 1.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 3]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

Polyethylene terephthalate copolymerized with 8 mol% sodium 5-sulfoisophthalate was used as the sea component, polyethylene terephthalate was used as the island component, and a mixture of 20 mass% of an ocean component and 80 mass% To obtain a sea-island composite fiber having an island number of 16 degrees / filament and an average single fiber diameter of 30 mu m. The obtained sea-island composite fibers were cut into a staple with a fiber length of 51 mm to form a fibrous web through a card and a cross wrapper, and the fibrous web was formed into a nonwoven fabric by needle punching. The thus obtained nonwoven fabric was dipped in a bath at a temperature of 98 캜 for 2 minutes to shrink and dried at a temperature of 100 캜 for 5 minutes to obtain a nonwoven fabric for fibrous substrate.

(Application of PVA)

The same PVA aqueous solution as in Example 1 was used to obtain a PVA-imparted sheet having a PVA adhered amount of 30% by weight to the fibrous amount of the fibrous substrate nonwoven fabric.

(Microfiber (de-aeration))

The non-woven fabric for fibrous substrate was treated in the same manner as in Example 1 to obtain a de-seaized sheet from which marine components of sea-island complex fibers were removed. The average short fiber diameter on the surface of the deasphalted sheet was 4.4 mu m.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 4]

(Preparation of aqueous PVA solution)

PVA having a degree of saponification of 99% and a degree of polymerization of 1100 (NM-11 manufactured by Nippon Kosei Kagaku K.K.) was added to water at 25 占 폚. After the temperature was elevated to 90 占 폚, 90 占 폚 was maintained while stirring for 2 hours, % Aqueous solution to obtain a 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.

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

The above-mentioned nonwoven fabric for fibrous substrate was impregnated with the PVA aqueous solution and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having a PVA adhered amount of 30% by mass to the amount of fibrous nonwoven fabric.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 5]

(Preparation of aqueous PVA solution)

PVA having a degree of saponification of 99% and a degree of polymerization of 2600 (NH-26, manufactured by Nippon Kosei Kagaku K.K.) was added to water at 25 ° C, and after the temperature was raised to 90 ° C, the temperature was maintained at 90 ° C while stirring for 2 hours, % Aqueous solution to obtain a 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.

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

The above-mentioned nonwoven fabric for fibrous substrate was impregnated with the aqueous PVA solution and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having a PVA adhered amount of 10% by mass to the fibrous amount of the fibrous nonwoven fabric-based nonwoven fabric.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 6]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

Polyethylene terephthalate copolymerized with 8 mol% sodium 5-sulfoisophthalate was used as the sea component, polyethylene terephthalate was used as the island component, and a mixture of 20 mass% of an ocean component and 80 mass% To obtain a sea-island composite fiber having an island number of 16 degrees / filament and an average single fiber diameter of 30 mu m. The resultant sea-island composite fibers were cut to a fiber length of 51 mm to form a staple, and a fibrous web was formed through a card and a cross wrapper. On both sides of the web, 84 dtex-72 filaments of polyethylene terephthalate (PET) And a nonwoven fabric was formed by a needle punching process. The thus obtained nonwoven fabric was dipped in a bath at a temperature of 98 캜 for 2 minutes to shrink and dried at a temperature of 100 캜 for 5 minutes to obtain a nonwoven fabric for fibrous substrate.

(Application of PVA)

The above-mentioned nonwoven fabric for fibrous substrate was impregnated with the PVA aqueous solution described above and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having an amount of PVA adhered to the fibrous base material nonwoven fabric of 15% by mass.

(Microfiber (de-aeration))

The non-woven fabric for fibrous substrate was treated in the same manner as in Example 1 to obtain a de-seaized sheet from which marine components of sea-island complex fibers were removed. The average short fiber diameter on the surface of the deasphalted sheet was 4.4 mu m.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 7]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate was obtained in the same manner as in Example 1.

(Application of PVA)

A PVA-imparted sheet having a PVA adhering amount of 30% by mass with respect to the fiber amount of the nonwoven fabric for a fibrous substrate was obtained in the same manner as in Example 1.

(Microfiber (de-aeration))

A deaerated sheet was obtained in the same manner as in Example 1.

(Preparation of polyurethane liquid)

To 100 parts by mass of a solid content of a polycarbonate-based self-emulsifiable polyurethane liquid to which polyhexamethylene carbonate was applied to a polyol and dicyclohexylmethane diisocyanate was applied to the isocyanate, a thickener (manufactured by San Nopco Co., Ltd.) SN Tikner 627N) was added, and the whole was made up to 20% by mass of a polyurethane solid content by water to obtain a water-dispersed polyurethane solution.

(Impartation of polyurethane)

The above-described PVA-impregnated sheet was impregnated with the above-mentioned polyurethane solution, and then dried with hot air at a temperature of 100 캜 for 30 minutes to obtain a polyurethane, which had an adhesion amount of polyurethane to the amount of fibers of the nonwoven fabric of 30% To thereby obtain a sheet to which it was applied.

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Example 8]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

The above-mentioned nonwoven fabric for fibrous substrate was impregnated with the aqueous PVA solution and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having a PVA adhered amount of 10% by mass to the fibrous amount of the fibrous nonwoven fabric-based nonwoven fabric.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

(APS) as a heat coagulating agent was added to 100 parts by mass of a solid content of a polycarbonate-based self-emulsifiable polyurethane liquid to which polyhexamethylene carbonate was applied to a polyol and dicyclohexylmethane diisocyanate was applied to the isocyanate, 2 parts by mass was added, and the whole was made up to 20% by mass of solid content with water to obtain an aqueous dispersion type polyurethane solution. The thermal coagulation temperature was 72 ° C.

(Impartation of polyurethane)

The above described polyurethane solution was impregnated into the deaerated sheet to which the PVA was applied, coagulated in hot water at 80 캜, and hot air dried at 100 캜 for 15 minutes, whereby the amount of polyurethane adhering to the fibrous amount of the nonwoven fabric was 30% A polyurethane-applied sheet was obtained.

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

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

[Comparative Example 1]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Microfiber (de-aeration))

The fibrous nonwoven fabric obtained above was immersed in an aqueous solution of sodium hydroxide having a concentration of 10 g / liter heated to a temperature of 95 캜 and treated for 10 minutes to obtain a deasphalted sheet from which marine components of sea-island complex fibers were removed. The average short fiber diameter on the surface of the deasphalted sheet was 3 mu m.

(Application of PVA)

The deasphalted sheet was impregnated with the PVA aqueous solution obtained in Example 1 and heated and dried at a temperature of 140 캜 for 10 minutes to obtain a PVA-applied sheet having a PVA adhered amount of 30% by mass to the deasphalted sheet.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

The above-described PVA-applied deaerated sheet was impregnated with the above-mentioned polycarbonate-based polyurethane solution, treated for 5 minutes under a moist heat atmosphere at a temperature of 100 캜, then hot-air dried at a drying temperature of 120 캜 for 5 minutes, And subjected to a dry heat treatment at a temperature of 140 캜 for 2 minutes to obtain a sheet to which polyurethane was applied so that the amount of adhered polyurethane to the amount of ultrafine fiber was 30% by mass.

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

A sheet product was obtained in the same manner as in Example 1. The surface appearance of the obtained sheet product was good and had a soft texture, but the amount of abrasion loss was large.

[Comparative Example 2]

(Preparation of aqueous PVA solution)

PVA having a degree of saponification of 87% and a degree of polymerization of 500 (GL-05, manufactured by Nippon Kosei Kagaku K.K.) was added to water at 25 DEG C, and after the temperature was raised to 90 DEG C, the temperature was maintained at 90 DEG C with stirring for 2 hours, % Aqueous solution to obtain a 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.

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

The amount of PVA adhered to the amount of fibrous material in the nonwoven fabric for fibrous substrate was measured in the same manner as in Example 1 except that the above-mentioned nonwoven fabric for fibrous substrate was impregnated with the PVA aqueous solution and the squeezing after impregnation was controlled to change the amount of PVA adhered 10% by mass of PVA-imparted sheet.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

A sheet product was obtained in the same manner as in Example 1. The resulting sheet product was not uniformly applied by dissolving PVA in an aqueous alkaline solution or an aqueous polyurethane solution, and the surface appearance was poor in the dispersed state of the fibers, poor napping feeling and poor texture. .

[Comparative Example 3]

(Preparation of aqueous PVA solution)

PVA having a degree of saponification of 99% and a degree of polymerization of 500 (NL-05 manufactured by Nippon Kosei Kagaku K.K.) was added to water at 25 캜, and after the temperature was raised to 90 캜, the temperature was maintained at 90 캜 with stirring for 2 hours, % Aqueous solution to obtain a 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.

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

The amount of PVA adhered to the amount of fibrous material in the nonwoven fabric for fibrous substrate was measured in the same manner as in Example 1 except that the above-mentioned nonwoven fabric for fibrous substrate was impregnated with the PVA aqueous solution and the squeezing after impregnation was controlled to change the amount of PVA adhered 10% by mass of PVA-imparted sheet.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

A sheet product was obtained in the same manner as in Example 1. The resulting sheet product was not uniformly applied by dissolving PVA in an aqueous alkaline solution or an aqueous polyurethane solution, and the surface appearance was poor in the dispersed state of the fibers, poor napping feeling and poor texture. .

[Comparative Example 4]

(Preparation of aqueous PVA solution)

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

(Nonwoven fabric for fibrous substrate)

A nonwoven fabric for a fibrous substrate similar to that of Example 1 was used.

(Application of PVA)

Except that the amount of PVA adhered to the fibrous substance of the fibrous substrate-nonwoven fabric was 55% by mass or more, in the same manner as in Example 1, except that the same PVA aqueous solution as in Example 1 was used and the amount of PVA adhered was changed by controlling the squeezing after impregnation. Was obtained.

(Microfiber (de-aeration))

A defoaming sheet was obtained from the above nonwoven fabric for fibrous substrate in the same manner as in Example 1.

(Preparation of polyurethane liquid)

The same aqueous polyurethane solution as in Example 1 was used.

(Impartation of polyurethane)

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

(Removal of PVA)

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

(Half, brushed, dyeing, reduction washing)

A sheet product was obtained in the same manner as in Example 1. The obtained sheet product was soft in texture but had too much PVA, so that the holding of the fibers by the polyurethane was insufficient, and the surface appearance was too long for napping, resulting in poorer abrasion resistance.

[Comparative Example 5]

A sheet product was obtained in the same manner as in Example 1 except that the preparation of the aqueous PVA solution and the application and removal of the PVA were not carried out. The feeling of the obtained sheet product became hard. In addition, the surface appearance was poor because there was no napping.

Table 1 and Table 2 show the test conditions of the examples and comparative examples and the evaluation results of the sheet.

All of the sheet products obtained in Examples 1 to 8 had a good surface appearance, a flexible texture, and good wear resistance. On the other hand, the abrasion resistance of the sheet product obtained by Comparative Examples 1 and 4 was poor, and the sheet products obtained by Comparative Examples 2 to 5 all had poor surface appearance. In addition, the texture of the sheet-like product obtained by Comparative Examples 2, 3 and 5 was hard.

≪ Industrial applicability >

The sheet product obtained by the present invention can be used as a skin material such as furniture, a chair and a wall material, a seat in a vehicle room such as an automobile, a train and an airplane, an interior material such as a ceiling and an interior, As suitably used as industrial materials such as wiping cloths, polishing cloths and CD curtains, medical materials used in bags, belts, wallets and the like, such as shoes upper, trim, etc. of casual shoes, sports shoes, .

Claims (6)

Wherein the following steps 1 to 5 are carried out in order.
1. A process for producing a polyvinyl alcohol aqueous solution having a concentration of methyl acetate, acetic acid and methanol of 50 ppm or less by dissolving polyvinyl alcohol having a degree of saponification of 98% or more and a degree of polymerization of 800 to 3500 in water,
2. A process for producing a fibrous base material comprising the steps of applying 0.1 to 50 mass% of the polyvinyl alcohol to the amount of fibers contained in the fibrous base material by applying the aqueous polyvinyl alcohol solution to the fibrous base material having the ultrafine fiber-
3. A process for producing microfine fibers having an average single fiber diameter of 0.3 to 7 占 퐉 from a fibrous base material containing microfine fiber-
4. A process for producing a water-dispersible polyurethane, comprising the steps of providing a water-dispersible polyurethane to a fibrous base material having microvoled fibers imparted with the polyvinyl alcohol as a main constituent,
5. Step of removing polyvinyl alcohol from the fibrous base material containing microfine fibers imparted with the corresponding water-dispersed polyurethane as a main component The sheet-like water producing method according to claim 1, wherein the concentration of methyl acetate, acetic acid, and methanol in the polyvinyl alcohol aqueous solution is 0.1 to 50 ppm, respectively. The method for producing a sheet product according to claim 1 or 2, wherein the step of expressing the microfine fibers is a step of treating with an alkali aqueous solution. The sheet-like water producing method according to any one of claims 1 to 3, further comprising the step of applying the polyvinyl alcohol and heating at 80 to 170 占 폚. The sheet-like water producing method according to any one of claims 1 to 4, wherein the fibrous base material comprising the ultrafine fiber-forming fiber as a main constituent is integrated with the fabric and / or the knitted fabric. A sheet member according to any one of claims 1 to 5, wherein the density of the sheet is 0.2 to 0.7 g / cm 3.