JP2004225185A - Leathery sheet base and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a leathery sheet with favorable touch feeling and natural crease feeling, composed of a polymeric elastomer and conjugate staple fibers causing neither debonding nor splitting in the longitudinal direction even after subjected to carding and/or needlepunching treatment but splittable when subjected to the subsequent hot water bath treatment. <P>SOLUTION: The method for producing the leathery sheet base comprises imparting a nonwoven fabric comprising the conjugate staple fibers with the polymeric elastomer followed by undergoing a hot water treatment at a temperature -5 to +10°C relative to the glass transition point of the component higher in glass transition point than the other component composing the staple fibers and then splitting treatment in the hot water bath. In this leathery sheet base, the conjugate staple fibers are such that in the cross section, the two components, i.e. a polymer A and a polymer B, are disposed in a multilayer (totaling ≥5) laminated structure with the polymer A covering the polymer B so that the ratio of the maximum diameter of the fiber to the covering thickness fall within a specific range. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a leather-like sheet substrate and the obtained leather-like sheet substrate. More specifically, the present invention provides a step of manufacturing a leather-like sheet base material composed of fibers obtained by dividing a bonded-type composite staple into ultrafine fibers and a polymer elastic body, and performing a hot water treatment before splitting and separating the constituent fibers. The present invention relates to a production method characterized by performing the method and a leather-like sheet substrate obtained by the method.
[0002]
In order to produce ultrafine fibers having a single fineness of 0.1 decitex or less, direct spinning tends to cause yarn breakage, so there is a limit to fineness, and a composite spinning method has been conventionally used. Composite spun fibers obtained by the composite spinning method can be roughly classified into the following two types in terms of fiber cross-section: (1) a junction type in which two components are highly divided and arranged mutually (multilayer bonding type, petal type, etc.); However, there is a sea-island type highly dispersed in other components. In the case of the sea-island type fiber of (2), an ultrafine fiber of 0.001 denier or less can be obtained by removing the sea component. However, in order to remove the sea component, for example, the sea component is polyethylene or polystyrene. In the case of (1), it is necessary to use an organic solvent such as toluene or perchrene, and in the case of an alkali-soluble modified polyethylene terephthalate or the like, it is necessary to use a high-concentration alkaline solution. In recent years, use of such an organic solvent and reduction of a high-concentration alkaline solution and its neutralized waste solution have been demanded from an environmental point of view.
[0003]
In addition, since the removed sea component is difficult to reuse, an increase in the amount of waste is inevitable. From the viewpoint of ecology, it is preferable to obtain the ultrafine fiber from the bonded fiber of (1), in which the removal of one component is unnecessary. . In such a conjugated composite fiber, a fiber having a sharp edge or an ultrafine fiber is formed by exfoliation of its components, and as described in the official gazette, (1) benzyl alcohol A method in which one component is swollen with a liquid containing a chemical solution as described above and separated from each other by the force (for example, see Patent Document 1). {Circle over (2)} Physical force, that is, a method of forcibly separating the surface by rubbing, crushing, buffing, etc., or by jetting a water jet stream (for example, Patent Documents 2 to 4). reference.).
[0004]
[Patent Document 1]
JP-A-54-96181
[Patent Document 2]
JP-B-53-10170
[Patent Document 3]
JP-A-2-169722
[Patent Document 4]
JP-A-9-217233
[0005]
When producing a leather-like sheet from such fibers, the splitting treatment is performed after producing a nonwoven fabric or after producing a nonwoven fabric and applying a polymer elastic body, and as a result, a leather-like sheet having a soft and excellent texture is obtained. Although a sheet can be obtained, if splitting occurs in the previous step of forming a nonwoven fabric, the passability and yield of the process are significantly deteriorated, and the obtained nonwoven fabric is also nonuniform and the texture is extremely poor. Specifically, when a card is used in the production of a nonwoven fabric, the components of the bonded conjugate fiber are peeled off, the fiber is thinned, a nep is generated, and the clogging of the fiber causes a significant reduction in the spinning speed. Or a stable spinning cannot be performed. In addition, when a needle punch is used to entangle the fibers, there is a problem that peeling occurs due to damage, the single fibers are hardly entangled, and the peel strength of the nonwoven fabric does not increase.
[0006]
However, on the other hand, there is a method of increasing the adhesiveness of the two components constituting the fiber in order not to cause such deterioration in the processability, but this method does not cause a problem in forming a nonwoven fabric, Even after performing the splitting process described above as a post-process, it does not split at all, splits only a small part, or requires a very strong physical force to split all, It is not a preferable method because it requires an extremely long time treatment or a use of a high-concentration alkaline solution.
Then, as another method, a method of coating the other component with one of the two components has recently been proposed. As such an example, there is described a composite fiber having a petal-shaped cross-sectional structure of eight or more divisions in which one component covers another component (see Patent Document 5). In the case of a petal type, the distance between the two components becomes narrower toward the center, and it is difficult to completely split the number of apparent layers because one component is substantially connected at the center. The texture of a leather-like sheet made of a nonwoven fabric obtained from such fibers is inferior to that of a leather-like sheet obtained from a conventional nonwoven fabric made of ultrafine fibers.
[0007]
[Patent Document 5]
JP-A-2000-129538
[0008]
[Problems to be solved by the invention]
As described above, the splitting method of two components includes: (1) a method in which one component is swollen with a liquid containing a chemical such as benzyl alcohol, and separated from each other by the force; (2) a physical force. That is, the method of forcibly separating the surface by rubbing, rubbing, treating the surface with buffing or the like, or spraying a water jet stream, has been mentioned. In the method of (1), the organic solvent is used. Is a problem from an ecological point of view because swelling agent is used as the swelling agent. In the method (2), a leather-like sheet base having a thickness of about 1.0 to 2.0 mm used for sports shoes and the like is used. In the production of a material, the separation or division of the fiber component does not progress particularly toward the center, and therefore, each has its own problems such as inferior texture.
[0009]
Furthermore, as a splitting method other than the above, (4) by kneading in hot water of 100 ° C. or higher, the force of the two components trying to separate from each other due to the difference in the thermal swelling rate and the external stress by the firs are simultaneously increased. A method of acting and separating can be considered, but if the treatment is carried out rapidly at a temperature of 100 ° C. or more, a sudden change such as shrinkage occurs in the constituents of the fiber, which causes baking and wrinkles, and lowers the appearance. Was causing it.
[0010]
[Means for Solving the Problems]
The present inventors have made it possible to form a non-woven fabric without substantial peeling and splitting in the longitudinal direction of the fibers even after card treatment and needle punching treatment, and in the subsequent splitting treatment, an organic solvent or alkaline It is made of ultra-fine fibers that have a low environmental impact by using bonded composite staple fibers that can be split quickly with the physical force used in conventional relaxation processing without using an aqueous solution. As a result of intensive studies on obtaining a leather-like sheet having an excellent texture, the inventors have found that the above-mentioned problems can be solved by using the method described below. That is, the present invention is characterized in that the following steps (1) to (4) are performed in the order of (1) → (2) → (3) → (4) in a method for producing a leather-like sheet substrate. A method for producing a leather-like sheet base material.
(1) In a fiber comprising two types of polymer components having different A and B, the total number of laminated layers of component A and component B is 5 or more, and component A has a cross-sectional structure in which component B is coated. And a composite type staple fiber having a ratio (t / d) of the minimum thickness (t) of the coated portion of the component A to the maximum fiber diameter (d) in the range of 0.005 to 0.03. The process of manufacturing nonwoven fabric,
(2) a step of providing a polymer elastic body to the nonwoven fabric,
(3) a step of performing a hydrothermal treatment in a temperature range T represented by Tg-5 ≦ T ≦ Tg + 10 with respect to a glass transition point Tg of at least one of the components constituting the fiber;
(4) a step of splitting the component A and the component B with hot water at 100 to 140 ° C;
Furthermore, in the step of splitting the component A and the component B, the method is a method for producing a leather-like sheet substrate using a jet dyeing machine, and the leather-like sheet substrate obtained by these production methods.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The bonded conjugate fiber used in the present invention has a multi-layer laminated cross-sectional structure in which the component A covers the component B among the polymer components of the components A and B constituting the bonded conjugate fiber, and a coating layer portion. It is important that the ratio (t / d) of the minimum thickness (t) of the coated portion of the component A and the maximum diameter (d) of the fiber is in the range of 0.005 to 0.03. Further, a preferable range of t / d is a range of 0.007 to 0.02. When t / d is less than 0.005, the coating of the polymer B is insufficient, and in any one of the steps of fiber drawing, mechanical crimping, card opening, and needle punch entanglement, Since a large amount of cracks are generated, for example, a large amount of neps are generated in the card device, which causes a problem that stable web production becomes impossible. On the other hand, when t / d is larger than 0.03, the fiber can be stably produced without cracking until the nonwoven fabric manufacturing step, but the fiber is easily split in a hot water bath or the like in the subsequent splitting processing step. You will not be able to do it. For example, when the polymer A is a polyester compound and the t / d is greater than 0.03, the fibers cannot be split easily in a hot water bath in order to make the fibers extremely fine. As a result, a treatment with a liquid had to be used, and the present invention was not satisfied.
[0012]
As both polymers A and B that can be used in the bonded conjugate fiber according to the present invention, if they are combined in consideration of the relative balance of the SP value and the melt viscosity, the spinnable weight depends on the application and performance. It can be appropriately selected from the union. Examples thereof include polyester polymers such as polyethylene terephthalate and polybutylene terephthalate, polyolefin polymers such as polyethylene and polypropylene, polyamide polymers such as nylon 6 and nylon 66, and other polystyrene polymers and polyvinyl Examples thereof include alcohol-based polymers and vinyl alcohol-ethylene copolymers, and one or more of each component is used. Among them, a combination of a polyester polymer, particularly a polyethylene terephthalate polymer and a polyamide polymer can be suitably used as the A and B components because the leather-like sheet obtained has an excellent texture. In view of the above, it is more preferable that the component A uses a polyamide polymer and the component B uses a polyethylene terephthalate polymer.
[0013]
The polyester polymer represented by the polyethylene terephthalate polymer has one or more other dicarboxylic acid components, oxycarboxylic acid components, and other diol components as copolymer units, if necessary. May be. In this case, the other dicarboxylic acid component includes aromatic dicarboxylic acids such as diphenyldicarboxylic acid and naphthalenedicarboxylic acid or ester-forming derivatives thereof; dimethyl 5-sodium sulfoisophthalate, bis (5-sodium sulfoisophthalate) (2 -Hydroxyethyl) or the like, or a metal sulfonate group-containing aromatic carboxylic acid or a derivative thereof; an oxalic acid, adipic acid, sebacic acid, dodecane diacid, or another such aliphatic dicarboxylic acid or an ester-forming derivative thereof. Examples of the oxycarboxylic acid component include p-oxybenzoic acid, p-β-oxyethoxybenzoic acid, and ester-forming derivatives thereof. Examples of the diol component include aliphatic diols such as diethylene glycol, 1,3-propanediol, 1,6-hexanediol, and neopentyl glycol; 1,4-bis (β-oxyethoxy) benzene, polyethylene glycol, and polybutylene glycol. Can be mentioned.
[0014]
The above-mentioned polyamide-based polymer is obtained from known nylon 4, nylon 6, nylon 66, nylon 7, nylon 610, nylon 11, nylon 12, bis (p-aminocyclohexyl) methane and 1,10-decamethylenedicarboxylic acid. Polyamides, polyamides derived from 1,9-nonamethylene dicarboxylic acid, and those obtained by copolymerizing these polyamide components and other components within a range that does not impair the effects of the present invention, or these polyamide components and other components Mixed within a range that does not impair the effects of the present invention. Among these polyamide compounds, nylon 6 can be preferably used because the leather-like sheet obtained has an excellent texture.
[0015]
The weight ratio of the polymer component A to the component B in the fiber is not problematic as long as the desired multilayered cross-sectional structure is formed, but is preferably in the range of 90/10 to 10/90. Preferably it is in the range of 80/20 to 20/80. However, when either one of the weight ratios of the A and B polymer components is less than 10%, when the components A and B are alternately arranged in the spinneret before being discharged from the spinneret, Since the amount of the polymer is small, it tends to be difficult to form a target cross section.
[0016]
In the present invention, it is important that the cross-sectional structure of the fiber is a multilayer lamination type having five or more layers in total of A and B. In the present invention, such fibers can not only be split smoothly, but also have a flat cross-sectional surface portion and an original side surface portion of the fiber obtained by the splitting process, and are obtained by the splitting process. When the cross-sectional shape of the fiber to be applied stresses the leather-like sheet, the fiber is easily broken in the direction of the relatively flat split surface, for example, a circular cross-section formed with the same fineness, an elliptical cross-sectional structure. This has the effect that the texture becomes more flexible as compared to a leather-like sheet manufactured from a nonwoven fabric made of fibers having the same. If the number of layers is four or less, the fineness does not decrease even after the splitting treatment, and the texture of the obtained leather-like sheet is inferior. A more preferred number of layers is in the range of 9 to 20 layers. When the cross-sectional structure is petal-shaped, the distance between the two components becomes narrower toward the center, and since one component is substantially connected at the center, the fibers are completely split to the apparently counted layers. This is difficult and the leather-like sheet obtained has a poor texture.
[0017]
Splitting is also possible with the hollow petal type, but due to the presence of the hollow part, it is significantly inferior to the external stress of the fiber as compared with the multilayer lamination type, and cracks occur in the card opening process and the needle punch entanglement process In some cases. In addition, the petal type and the hollow petal type have a slower entanglement in the needle process than the multi-layer type, and the entanglement efficiency between the fibers is low. Poor physical property value.
In order to produce a bonded composite fiber having a multilayer laminated cross section in the present invention, the polymer component A and the component B are brought into a molten state, and the polymer component A and the component B are led alternately by a conventional method into a die nozzle hole. It can be manufactured by discharging from the nozzle hole. That is, both the components A and B are alternately arranged, and the component B and the metal of the die are brought into contact with the metal of the die by the surface tension of the component B until the polymer is discharged from the pores inside the die. Is rounded, and the component A flows into the clearance, whereby a bonded conjugate fiber having a coating in which the entire outer periphery of the cross section is covered by the component A can be obtained. The film thickness can be controlled by the SP values (solubility parameters) of the components A and B used and the absolute and relative values of the viscosity during spinning. For example, when the SP values of the polymer components A and B are high, the polar groups of both polymers tend to be rounded due to surface tension because the polar groups of the polymers are positioned so as to be as far apart from each other as possible.
[0018]
In addition, when the SP value of the component B is higher than the SP value of the component A, the end of the polymer B is rounded, and the polymer A easily flows into the gap between the base and the thick coating that covers the entire periphery of the cross section of the fiber. It is easy to form. However, even if the SP value of the component B is higher than the SP value of the component A, the apparent melt viscosity of the component A during spinning is higher than the apparent melt viscosity of the component B, and the effect of the melt viscosity difference is smaller than the SP value. If the difference is larger than the difference, the end of the polymer A is likely to be rounded, and it is difficult to form a film. When the apparent melt viscosity of the component B at the time of spinning is higher than the apparent melt viscosity of the component A, the end becomes rounder, and the polymer A easily flows into the gap between the die and the entire periphery of the cross section of the fiber. Easy to form a covering film. However, even if the apparent melt viscosity of the component B is higher than the apparent melt viscosity of the polymer A, the SP value of the component A during spinning is higher than the SP value of the component B, and is relatively higher than the difference between the SP values. If it is superior, the end of the polymer A tends to be rounded, and it is difficult to form a film.
[0019]
In order to make the end of the polymer B round and to make it easier for the polymer A to flow into the gap between the end and the die, depending on the balance between the SP value of the component A and the component B, or the balance of the melt viscosities, After alternately arranging both polymers in a molten state, it is necessary to lengthen the time until the polymer is discharged from the die nozzle hole. That is, by increasing the time from the die hole to the discharge, the polymer A wraps around due to the shearing effect due to the contact between the metal surface of the die nozzle hole and the polymer A, so that a film of the polymer A is easily formed. It is.
[0020]
The single-fiber fineness of the bonded composite staple fiber is not particularly limited, and the fineness can be arbitrarily selected depending on the application.However, since the texture of the obtained leather-like sheet is excellent, 0.5 to 10 decitex is more preferable. Is 2 to 7 dtex. Also, the cut length can be arbitrarily selected depending on the use. In addition, the fineness of each layer after splitting is preferable in terms of the texture of the leather-like sheet in which an average range of 0.01 to 1.0 decitex is obtained.Furthermore, as the fiber cross-sectional shape of each layer after splitting, The average length of each layer relative to the width of each layer is preferably in the range of 3 to 50 in terms of the flexibility of the obtained leather-like sheet. The cross-sectional shape of the bonded composite staple fiber is preferably such that the outer periphery is elliptical and the lamination surface is substantially parallel to the minor axis of the ellipse. Multi-layer lamination, and the shape in which the component A is coated with the component B does not substantially peel or split in the longitudinal direction of the fiber during a nonwoven fabric manufacturing process such as a card opening process and a needle punch entanglement process. The fibers after splitting are flattened, the fibers are easily broken in the direction of the relatively flat splitting surface, and the texture becomes soft.
[0021]
Various additives can be blended and used in the bonded composite staple fiber as needed. For example, catalysts, anti-coloring agents, heat-resistant agents, flame retardants, fluorescent whitening agents, matting agents, coloring agents, gloss improvers, antistatic agents, fragrances, deodorants, antibacterial agents, anti-mite agents, inorganic fine particles Etc. may be included. The additives may be blended in either one of the polymer A and the polymer B, or both.
[0022]
The nonwoven fabric used in the method of the present invention may have a moderate thickness and fullness made of the above-mentioned bonded composite staple fiber, and may have a soft texture. Can be arbitrarily selected, and is not particularly limited, but is preferably about 0.3 to 3.0 mm, and more preferably about 0.5 to 2.5 mm. The apparent density of the nonwoven fabric is 0.1 to 0.6 g / cm in order to obtain a leather-like sheet having a soft texture. ³ 0.15 to 0.55 g / cm ³ Is more preferable. 0.6g / cm apparent density ³ If it is larger, the resulting sheet tends to have a rubber-like texture. On the other hand, the apparent density is 0.1 g / cm ³ If it is smaller, the resilience and the feeling of waist are inferior, and the texture tends to be impaired.
[0023]
The nonwoven fabric used in the method of the present invention may be subjected to a treatment such as adhesion of a known compound such as a silicone-based or fluorine-based oil agent, a water repellent, a softener, an antistatic agent, a light stabilizer, or an ultraviolet absorber. it can. In addition, other fibers may be added to the nonwoven fabric in addition to the above-mentioned bonded staple fiber. Examples of the fiber entanglement method used when manufacturing the nonwoven fabric include a needle punching method and a water entanglement method, and the needle punching method provides a three-dimensional entangled nonwoven fabric more similar to a leather-like sheet. Further, it is preferable because a nonwoven fabric having a thickness of 1.0 mm or more that can be used for sports shoes or the like can be easily treated.
[0024]
The polymer elastic body used in the method of the present invention may be a polymer elastic body that has been conventionally used in producing a leather-like sheet. Examples of such a polymer elastic body include a polyurethane resin, an acrylic resin, a polyamide resin such as a polyamide elastomer, a polyester resin such as a polyester elastomer, a polystyrene resin having elasticity, and a polyolefin resin having elasticity. Of these, polyurethane-based resins and acrylic resins are preferably used because they give the leather-like sheet obtained an excellent texture.
[0025]
As a method of applying the resin, a so-called wet coagulation method in which a non-woven fabric is impregnated with a dimethylformamide solution such as polyurethane and wet coagulation in water, and washing is performed, and hot air, steam, microwave, hot water bath, etc. are impregnated with the emulsion. A suitable example is an emulsion method in which the resin is solidified or gelled and dried by any method. If the wet coagulation method is employed, a more natural leather-like texture can be obtained. Further, when an emulsion such as a polyurethane emulsion and an acrylic emulsion, particularly an aqueous emulsion dispersed only with water is used, the leather-like sheet obtained by the method of the present invention can be produced without using an organic solvent, This method is preferable because it is a method for producing a leather-like sheet that has less impact on the environment. The elastic polymer used in the method of the present invention may be an aqueous emulsion of the elastic polymer conventionally used in producing a leather-like sheet. Examples of such polymer elastic emulsions include polyurethane emulsions, acrylic emulsions, and urethane / acrylic complex emulsions. Among them, polyurethane emulsions and polyurethane emulsions are preferred because they give the leather-like sheet excellent texture. A urethane / acrylic composite emulsion is preferably used.
[0026]
When these emulsions have a thermosensitive gelling property, the emulsion particles can be thermosensitively gelled without causing migration and can be uniformly applied. The emulsion can be made thermogelling by emulsifying it with a nonionic surfactant having a low HLB as a surfactant to be emulsified, or by adding a substance called a migration inhibitor to the emulsion as a thermosensitive gelling agent. Examples of the heat-sensitive gelling agent to be added include, for example, inorganic salts such as calcium chloride and a polyethylene glycol-type nonionic surfactant, polyvinyl methyl ether, polypropylene glycol, a silicone polyether copolymer, and a polysiloxane. One or more of these can be used.
[0027]
A leather-like sheet comprising a fibrous substrate and a polymer elastic body can be produced by the following steps (1) to (4) in the order of (1) → (2) → (3) → (4). If this sequence is carried out, the splitting is performed after the polymer elastic body is applied to the nonwoven fabric, so that a leather-like sheet having a softened and excellent texture is preferably obtained. Further, by performing a heat press treatment using a hot roll or the like after the step (1) or the step (2), it is possible to obtain a desired specific gravity or form a smooth surface.
(1) In a fiber comprising two types of polymer components having different A and B, the total number of laminated layers of component A and component B is 5 or more, and component A has a cross-sectional structure in which component B is coated. And a composite staple fiber having a ratio (t / d) of the minimum thickness (t) of the component A of the covering portion to the maximum fiber diameter (d) in the range of 0.005 to 0.03. The process of manufacturing nonwoven fabric,
(2) a step of providing a polymer elastic body to the nonwoven fabric,
(3) a step of performing a hydrothermal treatment in a temperature range T represented by Tg-5 ≦ T ≦ Tg + 10 with respect to a glass transition point Tg of at least one of the components constituting the fiber;
(4) a step of splitting the component A and the component B with hot water at 100 to 140 ° C;
[0028]
The weight ratio between the nonwoven fabric and the elastic polymer constituting the obtained leather-like sheet can be appropriately selected depending on the application, but is generally preferably 5 to 150% by weight, and more preferably 15 to 120% by weight based on the weight of the nonwoven fabric. %, More preferably 30 to 100% by weight. If the content is less than 5% by weight, problems such as falling off of fibers, stretching of the nonwoven fabric during processing, and lack of fullness of the obtained sheet occur due to lack of a binder effect by the polymer elastic body. The texture of the sheet tends to be poor. On the other hand, if it exceeds 150% by weight, the obtained sheet tends to be hard and the texture of the leather-like sheet tends to be poor.
[0029]
In the present invention, one of the features is to split the component A and the component B to make them into ultrafine fibers. Prior to that, the glass transition point of at least one of the components A and B is defined as Tg. When expressed, it is essential to perform the hot water treatment in a temperature range T represented by Tg−5 ≦ T ≦ Tg + 10. The processing time is not particularly limited, but is usually selected from 10 to 60 minutes. Although the method of the hot water treatment is not particularly limited, it is preferable to perform the treatment with a dyeing machine such as a Wins dyeing machine, a dash line, or a circular machine. If the temperature is lower than Tg-5 ° C., there is almost no effect of eliminating the folding wrinkles generated when the treatment is performed at 100 ° C. or more in the subsequent step. Conversely, if the temperature is higher than Tg + 10 ° C., undesirably, there will be a tendency for folds and wrinkles to occur at the stage of the hot water treatment. Further, it is more preferable to perform the hydrothermal treatment in the temperature range of Tg−5 ≦ T ≦ Tg + 10 at each of the glass transition points of the components A and B. The reason why the hydrothermal treatment in such a temperature range is effective is that the distortion of the components constituting the fibers is gradually eliminated, or the components constituting the fibers are gradually contracted, such as gradually shrinking the fibers. I think that this is because of the change that has taken place. On the other hand, when the dry heat treatment is performed in the temperature range T, the same effect is not obtained, but the change in the molecular structure of the fiber component is promoted not only by heat but also by movement and flow of hot water. I believe that.
[0030]
Next, as a method of promoting the splitting of the component A and the component B, splitting in hot water or a hot water liquid to which a disperse dye is added becomes possible, thereby generating an alkali solution or a neutralized waste liquid thereof. A leather-like sheet base material can be obtained without the need. The splitting treatment in this case can be performed using, for example, a liquid dyeing machine such as a circular or a hot water bath, but the point of using hot water of 100 ° C. or more and the flexibility of the obtained leather-like sheet base material It is preferable to use a circular dyeing machine, etc. When the hot water treatment performed earlier is performed by a circular dyeing machine, after the hot water treatment, the temperature can be raised and the splitting treatment can be continuously performed.
[0031]
Furthermore, an important point in the present invention is the temperature at which the splitting treatment with hot water is performed, and the treatment temperature needs to be 100 to 140 ° C. Fibers and resins forming the leather-like sheet base material are easily softened in hot water of 100 ° C. or higher in a pressurized system, and the component B is formed by the component A by a synergistic effect of this and a physical force in a circular dyeing machine. Despite being covered, the splitting proceeds, and it is considered that the soft leather-like sheet base material has an excellent texture due to a relaxing effect. Therefore, if the processing temperature is lower than 100 ° C., the splitting of the fiber component of the obtained sheet base material does not proceed, resulting in poor flexibility, or a very long time of processing to develop the same flexibility. Will be required. When the processing temperature is 100 to 140 ° C., the fiber can be split by performing the processing in about 10 minutes to 1 hour. For the above reasons, the higher the processing temperature, the more the leather-like sheet base obtained by the splitting progress and relaxation effect tends to have a softer and more uniform texture. However, when the temperature is higher than 140 ° C., the resin component or the fiber component constituting the sheet base material is deteriorated, so that the feeling may be deteriorated or the physical properties may be deteriorated. Further, as an auxiliary means for further progressing the splitting, a physical force after the formation of the nonwoven fabric, that is, a processing method of performing a process of scraping or rubbing or a water jet flow process can be used. .
[0032]
The leather-like sheet obtained by the method of the present invention has a moderate flexibility and a sense of fulfillment, and is used for mattresses, bag lining materials, clothing interlining, shoe cores, cushioning materials, automobile interior materials, wall materials, carpets, and the like. It can be suitably used. Further, by applying polyurethane or the like to one surface by a known method to form a resin coating layer, it can be suitably used as artificial leather with silver used for sports shoes, men's shoes, bags and the like. In this case, when the surface layer is dry-formed using an aqueous emulsion such as polyurethane, an artificial leather with silver can be obtained without using an organic solvent. Also, suede-like artificial leather can be obtained by buffing the surface with emery paper or the like. Of course, the formation of the resin coating layer and the buffing treatment can also be performed prior to the hot water treatment.
[0033]
【Example】
Hereinafter, the method of the present invention will be described specifically with reference to examples, but the present invention is not limited thereto. In the following examples, the following methods were used to evaluate the jointed composite staple fiber obtained by combining various high-molecular polymers through a card, a needle punch, and a split state after splitting.
[0034]
[Maximum diameter of fiber (d) and coating thickness (t)]: From a photograph of a cross section of a fiber tow prepared by cutting with a razor and taken with a scanning electron microscope (× 1000 to 20000), the maximum diameter of the fiber and coating of the coating component were obtained. The thickness (thickness of the thinnest portion of the covering portion) was determined, and t / d was determined. Five fibers were randomly selected and observed, and the average of t / d was calculated.
[0035]
[Card processing passability]; 50 g / m ² A web was made through a miniature card so as to have a basis weight of, a tow was made from the fiber taken out of this fleece, cut with a razor, and about 400 side surfaces were observed with a scanning electron microscope and cracked. The counts were counted and the splitting ratio was determined by the following formula.
Splitting rate (%) = (number of broken fibers / total number of fibers) x 100 (%)
[0036]
[Needle punching treatment passability]; fleece obtained through the steps of card and cross wrapper are appropriately laminated, and 800 pieces / cm ² After performing the needle punching, a tow is produced from the fiber taken out and cut, and about 400 side surfaces are observed with a scanning electron microscope for the inner state of the web. To determine the splitting ratio.
Splitting rate (%) = (number of broken fibers / total number of fibers) x 100 (%)
[0037]
[Split treatment] The split ratio was determined by the following formula from observation of a scanning electron micrograph of the leather-like sheet obtained by performing split treatment with hot water.
Splitting rate (%) = (number of broken fibers / total number of fibers) x 100 (%)
[0038]
Example 1
Using nylon 6 (glass transition point = 40 ° C.) as the polymer component A and polyethylene terephthalate (glass transition point = 69 ° C.) as the polymer component B, the weight ratio is 66/34, and alternately into 11 layers. After the arrangement, the mixture was discharged from a die and spun. Then, after stretching and mechanical crimping, the resultant was cut into 51 mm to obtain a composite staple fiber having a cross-sectional shape in which nylon 6 of the type shown in FIG. The fineness of the obtained composite staple fiber was 3.3 dtex, and the ratio (t / d) of the maximum diameter (d) of the fiber to the minimum thickness (t) of the polymer component A of the coating component was 0.007. The ratio of the length to the width in the fiber cross section of each layer constituting the fiber was 6.7 on average, and the average fineness of each layer was 0.30 dtex.
[0039]
Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the splitting of the fiber was 1.8%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a nonwoven fabric was obtained by performing a needle punching treatment. The process passability was good. The splitting of the fiber at this point was 2.6%. A polymer elastic material (aqueous polyurethane emulsion bondic 1310NSA (polyurethane emulsion manufactured by Dainippon Ink and Chemicals, Inc.)) was placed inside the nonwoven fabric thus obtained so that the solid content after drying was 80% by weight of the nonwoven fabric. After impregnating and drying, the surface was smoothed and the specific gravity was adjusted by a hot press at 165 ° C. to obtain a sheet 1.
[0040]
The obtained sheet 1 was subjected to a hot water treatment in a circular dyeing machine at 75 ° C. (a condition 6 ° C. higher than the Tg of polyethylene terephthalate used as the polymer component B) for 30 minutes, and then the temperature was raised as it was. A splitting treatment was performed at 110 ° C. for 40 minutes, and the sheet base was obtained through drying. The obtained sheet was a leather-like sheet having a fine texture and a fine wrinkle feeling and an excellent texture. As a result of cross-sectional observation, the splitting of the fiber was 92%. Further, a 40-μm-thick polyurethane film colored with a white pigment was attached to one surface of the obtained sheet with a water-based polyurethane adhesive to form a dry surface to obtain artificial leather with silver. The obtained artificial leather with silver had soft and natural creases and was excellent in texture.
[0041]
Comparative Example 1
The sheet 1 obtained in Example 1 was treated at 75 ° C. for one hour only by heat-sensitive heat treatment without using hot water, and then subjected to splitting treatment at 110 ° C. for 40 minutes using a circular dyeing machine, followed by drying. Thus, a sheet substrate was obtained. In the obtained sheet, a large number of wrinkles exhibiting a large and deep fold feeling were generated, and the feeling was generally hard. As a result of cross-sectional observation, the splitting of the fiber was 90%. On one side of this sheet, a dry-formed surface was obtained in the same manner as in Example 1 to obtain artificial leather with silver, but the texture was hard, and large deep wrinkles observed on the sheet base material appeared on the silver surface as they were, The appearance of the leather-like sheet-like material was inferior.
[0042]
Comparative Example 2
The sheet 1 obtained in Example 1 was subjected to splitting treatment at 110 ° C. for 40 minutes using a circular dyeing machine as it was, and dried to obtain a sheet base material. In the obtained sheet, a large number of wrinkles exhibiting a large and deep fold feeling were generated, and the feeling was generally hard. As a result of cross-sectional observation, the splitting of the fiber was 90%. On one side of this sheet, a dry-formed surface was obtained in the same manner as in Example 1 to obtain artificial leather with silver, but the texture was hard, and large deep wrinkles observed on the sheet base material appeared on the silver surface as they were, The appearance of the leather-like sheet-like material was inferior.
[0043]
【The invention's effect】
According to the method of the present invention, a natural fold made of a nonwoven fabric made of a bonded composite staple fiber and a polymer elastic material, which is excellent in process passability, and can be easily split in a hot water bath to form an ultrafine fiber thereafter A leather-like sheet base material having a wrinkle feeling and an excellent texture can be obtained.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a cross section of a bonded composite staple fiber used in the method of the present invention.
FIG. 2 is a diagram showing another example of a cross section of the bonded composite staple fiber used in the method of the present invention.
FIG. 3 is a view showing an example of a cross section of a bonded composite staple fiber not belonging to the present invention.
[Explanation of symbols]
1 Component A
2 Component B
d Maximum diameter of fiber
t Minimum thickness of the coated part of component A

Claims (3)

In a method for producing a leather-like sheet substrate, the following steps (1) to (4) are performed in the order of (1) → (2) → (3) → (4). The method of manufacturing the material.
(1) In a fiber composed of two kinds of polymer components having different A and B, the cross-sectional structure in which the total number of laminated layers of the component A and the component B is 5 or more and the component A covers the component B And a bonded staple fiber having a ratio (t / d) between the minimum thickness (t) of the coated portion of the component A and the maximum fiber diameter (d) in the range of 0.005 to 0.03. Manufacturing nonwoven fabric,
(2) a step of providing a polymer elastic body to the nonwoven fabric,
(3) a step of performing a hydrothermal treatment in a temperature range T represented by Tg-5 ≦ T ≦ Tg + 10 with respect to a glass transition point (Tg) of at least one of the components constituting the fiber;
(4) a step of splitting the component A and the component B with hot water at 100 to 140 ° C; The method for producing a leather-like sheet base according to claim 1, wherein a liquid jet dyeing machine is used in the step of splitting the component A and the component B. A leather-like sheet substrate obtained by the production method according to claim 1.

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