JP2002061080A - Method for producing leathery sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a leathery sheet comprising side- by-side conjugate staple fibers and a polymeric elastomer, excellent in a touch feeling, and not peeling and splitting the fibers in the longitudinal direction of the fibers eve after carding and needle punching treatments. SOLUTION: A nonwoven fabric is prepared form the side-by-side conjugate staple fibers in which polymer A and a polymer B are alternately arranged in a weight ratio of the polymer A to the polymer B within the range of (90/10) to (10/90) and the polymer A is 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate modified within a specific range and the polymer B has a solubility parameter within a specific range in the cross section of the fibers and the resultant nonwoven fabric is subsequently impregnated with the polymeric elastomer and then subjected to splitting treatment with an aqueous solution of an alkali at a low concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a leather-like sheet. More specifically, the present invention can produce ultrafine fibers without using an organic solvent or a high-concentration aqueous alkaline solution, and does not peel off in the longitudinal direction of the fibers even after card processing and needle punching. The present invention relates to a method for producing a leather-like sheet comprising a bonded type composite fiber and an elastic polymer.

[0002] In order to produce ultrafine fibers having a single fiber of 0.1 decitex or less, there is a limit in fineness because direct spinning is likely to occur, and composite spinning means has been conventionally used. The conjugate fiber obtained by the conjugate spinning method is roughly classified into two types: a junction type (multilayer type, petal type, etc.) in which two components are highly divided and arranged in a cross section.
There is a sea-island type where components are highly dispersed in other components. In the case of sea-island type fibers, ultrafine fibers of 0.001 decitex or less can be obtained by removing the sea component.However, in order to remove the sea component, for example, when the sea component is polyethylene or polystyrene, etc. Requires the use of an organic solvent such as toluene and perchrene. In the case of modified polyethylene terephthalate which is easily soluble in alkali, a high-concentration alkali solution must be used. recent years,
From the environmental point of view, the use of such organic solvents and the reduction of high-concentration alkaline solutions and their neutralized waste solutions are required. In addition, since the removed sea component is difficult to reuse, an increase in the amount of waste is inevitable, and from the viewpoint of ecology, a method of obtaining ultrafine fibers from bonded fibers, which eliminates the need to remove one component, is preferred. In such bonded conjugate fibers, fibers having sharp edges and ultrafine fibers are formed due to the mutual separation of the components, and the separation method includes benzyl alcohol as disclosed in JP-A-54-96181. A method in which one component is shrunk with a liquid containing a chemical solution such as described above, and peeled off by the force.
As can be seen in JP-169722, JP-A-9-217233, physical force, that is, scraping, rubbing, buffing and the like,
For example, a method of forcibly peeling off by jetting a water jet stream or a method of slightly dissolving one component in a low-concentration aqueous alkali solution to peel off can be exemplified. As a method for peeling a bonded portion in a known method for producing a leather-like sheet made of a nonwoven fabric made of such a bonded conjugate fiber and a polymer elastic body, the method uses an organic solvent as a swelling agent. In the method, only the vicinity of the surface of the sheet is peeled off, and if the thickness of the sheet is more than 0.5 mm, the texture becomes hard, so it is not a preferable method because it can be applied only to thin materials, but after all, the method of Is a more effective method.

[0003]

When a leather-like sheet is produced from such fibers, the peeling treatment is carried out after the production of the nonwoven fabric or after the production of the nonwoven fabric and the application of a polymer elastic body. A leather-like sheet having an excellent texture can be obtained, but if peeling occurs in the process of forming the nonwoven fabric before that, the process passability, the yield is significantly deteriorated,
The resulting non-woven fabric is also non-uniform and has a very poor feel. Specifically, when a non-woven fabric is used, when a card is used, the joint of the bonded type composite fiber is peeled, the fineness is reduced, and the generated neps are clogged, so that the spinning speed must be significantly reduced. It becomes necessary or accumulates in the card device, making stable spinning impossible. 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. However, on the other hand, if the adhesiveness of the two components constituting the fiber is increased in order not to cause such deterioration in the process passability, there is no problem in forming the nonwoven fabric, but instead the above-described peeling is performed as a subsequent process. Does not peel off even after processing, peels off only a very small part, requires extremely strong physical force to peel off all, or requires extremely long processing to peel off It is necessary to use a high concentration alkaline solution.

[0004]

Means for Solving the Problems The present inventors have made it possible to form a nonwoven fabric without peeling in the longitudinal direction of the fibers even after card processing and needle punching processing, and in the subsequent peeling processing, a slight physical The purpose of this study is to obtain a leather-like sheet that is made of ultrafine fibers with low environmental impact by using bonded staple fibers that can be quickly peeled off with a natural force and a low-concentration alkaline aqueous solution. As a result, the following steps (1) to
(3) is replaced by (1) → (2) → (3) or (1) →
It has been found that a method for producing a leather-like sheet characterized by performing the steps in the order of (3) → (2) solves the above problem. (1) In the cross-section of the fiber, in a bonded composite staple fiber having a structure in which two types of polymers A and B are alternately arranged, A is in the range of 0.5% to 7.0% of the dicarboxylic acid component. Is a copolymerized polyethylene terephthalate modified with 5-sodium sulfoisophthalic acid, B is a polymer having a solubility parameter (SP value) in the range of 10.0 to 15.0, and the weight ratio of A to B Is 90/1
A step of producing a nonwoven fabric from the bonded composite staple fiber in the range of 0 to 10/90 (2) a step of applying a polymer elastic body to the nonwoven fabric; and (3) a peeling of the bonded portion between the polymer A and the polymer B is zero. A step of using an aqueous solution of sodium hydroxide or potassium hydroxide having a concentration of not more than 3 mol / l

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The conjugated conjugate fiber used in the method of the present invention is one in which two types of polymers A and B, which are arranged alternately, are such that A is from 0.5% of the dicarboxylic acid component.
It is a copolymerized polyethylene terephthalate modified with 5-sodium sulfoisophthalic acid in the range of 7.0%, and B has a solubility parameter (SP value) of 10.0 to
It is important that the polymer be in the range of 15.0.

[0006] The polymer A in the present invention is SP
5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate is used for the purpose of enhancing the adhesion to the polymer having a value in the range of 10.0 to 15.0, and the amount of modification is 0 in terms of the molar ratio of the dicarboxylic acid component. It is important that the denatured material is in the range of 0.5% to 7.0%. Preferably, the amount of conversion is 0.8 to 6.0 mol%. Metamorphosis is 0.5
%, The adhesiveness to the B polymer is insufficient, so that a large amount of peeling occurs at the stage of fiber drawing, carding, and needle punching. For example, a large amount of nep occurs in a card device. This causes problems such as impossible spinning. On the other hand, if the amount of denaturation is greater than 7.0%, peeling does not occur in the steps up to the production of the nonwoven fabric, but it cannot be easily peeled in the subsequent steps. For example, when the amount of denaturation is greater than 7.0%, peeling can be sufficiently performed with an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution having a concentration of 0.3 mol / l or less. In order to achieve ultrafineness, it is necessary to extract and remove 5% or more of the polyester component due to a strong alkali, so that the same conditions as those of the so-called conventionally used alkali weight reduction treatment are required, which is unsuitable from the gist of the present invention. Becomes In addition, the 5-sodium sulfoisophthalic acid mentioned herein includes dimethyl 5-sodium sulfoisophthalate and bis (2-sodium sulfoisophthalate) (2-sodium sulfoisophthalate).
(Hydroxyethyl) and the like.

In the A polymer, other dicarboxylic acid components, oxycarboxylic acid components, and other components may be used, if necessary, as long as the control of the adhesion between the two types of polymers A and B of the present invention is not hindered. Or one or more of the above diol components as copolymerized units. In that case, as the other dicarboxylic acid component, diphenyl dicarboxylic acid, aromatic dicarboxylic acid such as naphthalenedicarboxylic acid or an ester-forming derivative thereof, oxalic acid, adipic acid, sebacic acid, aliphatic dicarboxylic acid such as dodecane diacid Acids or their ester-forming derivatives can be mentioned. 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, polypropylene glycol, and polybutylene. Glycols and the like can be mentioned.

The B component, which is the other component of the bonded conjugate fiber used in the method of the present invention, must have an SP value in the range of 10.0 to 15.0 as described above, and is preferably used. Has an SP value in the range of 11.0 to 14.0. If the SP value is smaller than 10.0, peeling occurs in the longitudinal direction of the fiber after the card processing and the needle punching processing. On the other hand, when the SP value is larger than 15.0, there is no problem in forming the nonwoven fabric, but the subsequent peeling treatment becomes extremely difficult, as described above for the A polymer. Note that the SP value mentioned here is
P. A. J. Small method (PAJ Sm)
all: J. Appl. Chem. , 3, 71 (195
3)) A method proposed by Fedors that improved (RF Fedors: Polym. Eng. Sc)
i. , 14 [2], 147 (1974)).

The weight ratio of the A polymer to the B polymer in the conjugate fiber is in the range of 90/10 to 10/90,
It is preferably in the range of 85/15 to 15/85, and more preferably in the range of 80/20 to 20/80. When one of the weight ratios of the A and B polymers is less than 10%, when the A polymer and the B polymer are alternately arranged before being discharged from the die,
Since the amount of one polymer is small, it is difficult to form a desired cross section.

[0010] In order to produce the bonded conjugate fiber used in the present invention, the polymer A and the polymer B are melted and led to a die nozzle hole while alternately arranging them in a conventional manner.
A method of discharging from the nozzle hole is used. Also, at this time, the polymers of A and B are alternately arranged, and the surface of the B polymer is brought into contact with the metal of the B polymer and the metal of the base until the polymer is discharged from the pores inside the base. The end is rounded due to the tension, and the A polymer flows into the gap there, so that it is possible to obtain a bonded composite fiber having a coating in which the entire outer periphery of the cross section is coated with the A polymer,
It can also be used as a means for improving the process passability.

The A and B polymers that can be used in the bonded conjugate fiber of the present invention include the above-mentioned denatured amount and SP.
If a combination that satisfies the relationship between the values is considered in consideration of the balance of the melt viscosity, the combination can be arbitrarily selected according to the application and performance. Examples of the B polymer 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 polystyrene polymers. Copolymers, polyvinyl alcohol-based polymers, vinyl alcohol-ethylene copolymers and the like can be mentioned, and one or two or more kinds are used for each component. Of these, polyamide polymers such as nylon 6 and nylon 66 are preferred.

The cross-sectional shape of the conjugated composite fiber can be a multilayer type, a petal type, or a hollow petal type depending on the application and performance. In order to obtain fibers of each cross-sectional shape, a corresponding nozzle nozzle hole structure may be used.

[0013] The single yarn fineness of the bonded composite staple fiber is
It is not particularly limited and can be arbitrarily selected depending on the application. Also, the cut length can be arbitrarily selected depending on the use.

Various kinds of additives can be blended and used in the joint type composite staple fiber as required. For example, catalysts, color inhibitors, heat-resistant agents, flame retardants, optical brighteners,
Matting agents, coloring agents, gloss improving agents, antistatic agents, fragrances, deodorants, antibacterial agents, anti-mite agents, inorganic fine particles and the like may be included. Further, the additive may be blended on one side of the A polymer or the B polymer, or on both sides.

[0015] The nonwoven fabric used in the method of the present invention may be of the above-mentioned bonded composite staple fiber, having an appropriate thickness and fullness, and having a soft texture, and the thickness of the nonwoven fabric is a leather-like sheet obtained. Can be arbitrarily selected depending on the use and the like, and is not particularly limited.
It is preferably about 3.0 mm,
More preferably, it is about mm. Apparent density of the fibrous base material, is preferably, 0.15~0.50g / cm ³ that in order to obtain a leather-like sheet having a soft texture is 0.1 to 0.6 g / cm ³ Is more preferable. If the apparent density is greater than 0.6 g / cm ³ , the resulting sheet tends to have a rubber-like texture. On the other hand, if the apparent density is less than 0.1 g / cm ³ , the resilience and the feeling of waist are inferior, and the texture tends to be impaired. The nonwoven fabric used in the method of the present invention may be subjected to a treatment such as attaching a known compound such as a silicone-based or fluorine-based oil agent, a water-repellent agent, a softener, an antistatic agent or a light-resistant stabilizer, or an ultraviolet absorber. it can.

The elastic polymer used in the method of the present invention comprises:
What is necessary is just a polymer elastic body that has been conventionally used when 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.

As a method for applying the resin, a non-woven fabric is impregnated with a dimethylformamide solution such as polyurethane,
Wet coagulation and dewatering in water, the so-called wet coagulation method, and emulsion method in which the resin is solidified or gelled and dried by impregnating the emulsion with hot air, steam, microwave, hot water bath, etc. Can be mentioned. If the wet coagulation method is adopted, a more natural leather-like texture can be obtained.

When an emulsion such as a polyurethane emulsion or 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. It is preferable because the method can produce a leather-like sheet which can be performed and has less impact on the environment. 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 thermogelled 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.

The leather-like sheet composed of the fibrous base and the elastic polymer is subjected to the steps (1) → (2) →
(3) or (1) → (3) → (2). In particular, it is preferable to carry out in the order of (1) → (2) → (3), since the exfoliation is performed after the elastic polymer is applied to the nonwoven fabric, and a leather-like sheet having a softened and excellent texture can be obtained. . Step (1) or step (2)
After that, a desired apparent density can be adjusted using a hot roll or the like, or a smooth surface can be formed.

The amount of resin applied to the obtained leather-like sheet can be appropriately selected depending on the application, but is generally preferably 5 to 150% by weight, more preferably 15 to 120% by weight, based on the weight of the nonwoven fabric. Is more preferable,
More preferably, it is 30 to 100% by weight. If the amount of resin adhered is less than 5% by weight, the resulting sheet lacks a sense of fulfillment and the texture of the leather-like sheet tends to deteriorate. 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.

In the method of the present invention, the joint between the polymer A and the polymer B is peeled off with a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution having a concentration of 0.3 mol / l or less. The peeling treatment can be performed using, for example, a circular dyeing machine or a jigger dyeing machine, or using a pad-roll method.However, since the obtained leather-like sheet has excellent flexibility, a circular dyeing machine or the like is used. It is preferable to use this method. The treatment temperature is preferably about 50 to 95 ° C. than the room temperature because the peeling proceeds rapidly, and the treatment time is 10 to 95 ° C.
Peeling is possible in about 1 minute to 1 hour.

The leather-like sheet obtained by the method of the present invention has moderate flexibility and a sense of fulfillment, and includes mattresses, bag lining materials, clothing interlining, shoe cores, cushioning materials, automobile interior materials, wall materials, It can be suitably used for carpets and the like. Further, by applying polyurethane or the like to one surface by a known method, it can be suitably used as artificial leather with silver used for sports shoes, men's shoes, bags and the like. At this time, when an aqueous emulsion is used as the polyurethane or the like for the skin layer, a silver surface can be provided without using an organic solvent. Also, suede-like artificial leather can be obtained by buffing the surface with emery paper or the like.

[0023]

EXAMPLES The method of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following examples, the card passing of the combined type composite staple fiber combining various polymers, the needle punch passing, the method of alkali peeling treatment and the method of evaluating the peeling state, the flexibility of the obtained sheet, the texture is by the following method evaluated.

[Card processing]: A web was made with a miniature card so as to have a basis weight of 50 g / m ^2, a fiber tow was made from this web, and cut with a razor to make a cross section of about 400 bundles. The state of the cross section was observed with a scanning electron microscope, the number of peeled portions was counted, and the peeling ratio was determined by the following equation. Peeling ratio (%) = (number of peeled fibers / total number of fibers) x
100 (%)

[Needle punching treatment]; the webs obtained through the card and cross wrapper processes are appropriately laminated,
After performing needle punching of 800 pieces / cm ^2, a tow is made from the taken out fiber and cut to form a cross section of about 400 bundles, and the cross section state is observed with a scanning electron microscope and peeled. The peeling ratio was determined by the following formula by counting the items. Peeling ratio (%) = (number of peeled fibers / total number of fibers) x
100 (%)

[Alkali stripping treatment]: Using a circular dyeing machine, a bath ratio of 30 using an aqueous solution of sodium hydroxide.
The peeling treatment was performed at 80 ° C. × 40 minutes. The cross section of the fiber was observed, and the peeling ratio was determined by the following equation. Peeling ratio (%) = (number of peeled fibers / total number of fibers) x
100 (%)

Example 1 Using 2.0% denatured 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate as the A polymer and nylon 6 (SP value: 12.4) as the B polymer,
After alternately arranging 11 layers at a weight ratio of 75/25, the mixture was discharged from a die and spun. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber having a cross-sectional shape shown in FIG. The obtained composite staple fiber had a single yarn fineness of 3.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the fiber peeling ratio was 0.6%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a needle punching treatment was performed, but the process passability was good. At this time, the fiber peeling ratio was 1.0%. The thus obtained nonwoven fabric is subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric having an apparent density of 0.30 g / cm ³ , and then an aqueous polyurethane emulsion [Bondick 1310NS]
(Polyurethane emulsion manufactured by Dainippon Ink and Chemicals, Inc.)] was impregnated so that the solid content after drying was 40% by weight of the nonwoven fabric, and after drying, the surface was smoothed and the apparent density was adjusted with a hot press at 160 ° C. Carried out. Further, the sheet was treated in a 0.15 mol / l aqueous solution of sodium hydroxide at 80 ° C. for 40 minutes using a circular dyeing machine, neutralized and dried to obtain a sheet. The obtained sheet was a leather-like sheet having an excellent texture. As a result of cross-sectional observation, the fiber peeling ratio was 96%.

COMPARATIVE EXAMPLE 1 A polymer was prepared by using 8.0% denatured 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate and a B polymer was prepared by using nylon 6 (SP value: 12.4).
After alternately arranging 11 layers at a weight ratio of 75/25, the mixture was discharged from a die and spun. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber having a cross-sectional shape shown in FIG. The obtained composite staple fiber had a single yarn fineness of 3.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the fiber peeling ratio was 0.3%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a needle punching treatment was performed, but the process passability was good. At this time, the fiber peeling ratio was 0.6%. The nonwoven fabric thus obtained is subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric with an apparent density of 0.27 g / cm ³ , and then an aqueous polyurethane emulsion [Bondic 1310NS]
(Polyurethane emulsion manufactured by Dainippon Ink and Chemicals, Inc.)] was impregnated so that the solid content after drying was 40% by weight of the nonwoven fabric, and after drying, the surface was smoothed and the apparent density was adjusted with a hot press at 160 ° C. Carried out. Further, the sheet was treated in a 0.15 mol / l aqueous sodium hydroxide solution at 80 ° C. for 40 minutes using a circular dyeing machine, neutralized and dried to obtain a sheet. The obtained sheet had a paper-like texture. As a result of cross-sectional observation, the peeling ratio of the fiber was 7.5%.

Comparative Example 2 Polyethylene terephthalate in which 2.0% was modified with 5-sodium sulfoisophthalic acid as the A polymer and nylon 6 as the B polymer were discharged from the nozzle hole at a weight ratio of 95/5. And spun. After spinning, it was stretched, mechanically crimped, and cut into 51 mm. When the cross section of the obtained composite staple fiber was viewed, 11 complete layers were not formed, and the target fiber could not be obtained.

Comparative Example 3 Using 0.2% denatured 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate as the A polymer and nylon 6 (SP value: 12.4) as the B polymer,
After alternately arranging 11 layers in a weight ratio of 75/25, the mixture was discharged from a die and spun. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber. The obtained composite staple fiber had a single yarn fineness of 3.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. The fiber peeling ratio was 24.8% immediately after card processing, and the card device was clogged after 3 hours in the web production, resulting in good results. You can no longer get webs.
Further, the web punch obtained within 3 hours of the card processing was subjected to needle punching, but showed a behavior of spreading slightly in the horizontal direction, and the process passability was poorer than that of Example 1.
The peeling ratio at this time was 33.5%. The nonwoven fabric thus obtained was subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric with an apparent density of 0.30 g / cm ³ , and then an aqueous polyurethane emulsion bondic 1310NS
(Polyurethane emulsion manufactured by Dainippon Ink and Chemicals, Inc.)
Was impregnated so that the solid content after drying was 40% by weight of the nonwoven fabric, and after drying, the surface was smoothed and the apparent density was adjusted by a hot press at 160 ° C. Further, the sheet was treated in a 0.15 mol / l aqueous sodium hydroxide solution at 80 ° C. for 40 minutes using a circular dyeing machine, neutralized and dried to obtain a sheet. The resulting sheet had a leather-like texture. As a result of cross-section observation, the fiber peeling rate was 97.
5%.

Example 2 Using a 4.0% denatured 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate as the A polymer and nylon 66 (SP value: 12.4) as the B polymer, a weight ratio of 35/65. Then, after alternately arranging them into 11 layers, they were discharged from a die and spun. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber. The obtained composite staple fiber had a single yarn fineness of 4.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the fiber peeling ratio was 0.5%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a needle punching treatment was performed, but the process passability was good. At this point, the fiber peeling rate was 2.2%. The thus obtained nonwoven fabric is subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric having an apparent density of 0.30 g / cm ³ , and then an aqueous polyurethane emulsion [Rezamin W-1800 (Polymer manufactured by Dainichi Seika Kogyo Co., Ltd.) Emulsion)] was impregnated so that the solid content after drying was 65% by weight of the nonwoven fabric, and after drying, the surface was smoothed and the apparent density was adjusted by a hot press at 160 ° C. Further, using a circular dyeing machine, 8
The sheet was treated in a 0.25 mol / l sodium hydroxide aqueous solution at 0 ° C. for 40 minutes, neutralized and dried to obtain a sheet. The obtained sheet was a leather-like sheet having an excellent texture. As a result of cross-sectional observation, the fiber peeling ratio was 96%.

Comparative Example 4 Using a 4.0% modified 5-sulfoisophthalic acid copolymerized polyethylene terephthalate as the A polymer and polypropylene (SP value: 8.0) as the B polymer, a weight ratio of 3
At 5/65, the layers were alternately arranged in 11 layers and then spun by discharging from a die. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber. The obtained composite staple fiber had a single yarn fineness of 4.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. Immediately after card processing, the fiber peeling ratio was 68%, and the card device was clogged, and a good web could be obtained continuously. Did not.

Example 3 1.0% denatured 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate as the A polymer, and vinyl alcohol-ethylene copolymer as the B polymer [ethylene / vinyl alcohol weight ratio = 60/40 ( SP value;
13.7)], the mixture was alternately arranged in 11 layers at a weight ratio of 75/25, and then spun by discharging from a die. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber. The obtained composite staple fiber had a single yarn fineness of 3.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the fiber peeling ratio was 1.0%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a needle punching treatment was performed, but the process passability was good.
The peeling ratio at this time was 2.5%. The nonwoven fabric thus obtained is subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric with an apparent density of 0.30 g / cm ³ , and then an aqueous polyurethane emulsion [Rezamin W-1800]
(Polyurethane emulsion manufactured by Dainichi Seika Kogyo Co., Ltd.)] is impregnated so that the solid content after drying is 40% by weight of the nonwoven fabric, and after drying, the surface is smoothed and the apparent density is adjusted by a 150 ° C. hot press. Was carried out. Further, the sheet was treated in a 0.15 mol / l aqueous solution of sodium hydroxide at 80 ° C. for 40 minutes using a circular dyeing machine, neutralized and dried to obtain a sheet. The obtained sheet was a leather-like sheet having an excellent texture. As a result of cross-sectional observation, the peeling ratio of the fibers was 95.5%.

Comparative Example 5 Polyethylene terephthalate obtained by modifying 1.0% with 5-sodium sulfoisophthalic acid as a polymer A, and a vinyl alcohol-ethylene copolymer [ethylene / vinyl alcohol weight ratio = 60/40 (B) as a polymer B SP value; 1
Using 6.6), the layers were alternately arranged in 11 layers at a weight ratio of 75/25, and then discharged from a die and spun. After spinning, it was stretched, mechanically crimped, and then cut to 51 mm to obtain a composite staple fiber. The obtained composite staple fiber had a single yarn fineness of 3.0 dtex. Using this composite staple fiber, card processing was performed to produce a web. After the card processing, the fiber peeling ratio was 0.2%. No process trouble occurred in the web preparation, and good passability was exhibited. Further, a needle punching treatment was performed, but the process passability was good. At this time, the fiber peeling ratio was 1.5%. The nonwoven fabric thus obtained is subjected to a shrinkage treatment in a hot water bath at 70 ° C. to give a nonwoven fabric with an apparent density of 0.30 g / cm ³ .
Aqueous polyurethane emulsion [Resamine W-1800
(Polyurethane emulsion manufactured by Dainichi Seika Kogyo Co., Ltd.)] is impregnated so that the solid content after drying is 40% by weight of the nonwoven fabric, and after drying, the surface is smoothed and the apparent density is adjusted by a 150 ° C. hot press. Was carried out. Further, the sheet was treated in a 0.15 mol / l aqueous sodium hydroxide solution at 80 ° C. for 40 minutes using a circular dyeing machine, neutralized and dried to obtain a sheet. The resulting sheet had a hard, paper-like texture. As a result of observation of the cross section, the peeling ratio of the fiber was 15%.

[0035]

According to the method of the present invention, excellent process passability is obtained.
Further, it is possible to obtain a leather-like sheet having an excellent texture, which is composed of a nonwoven fabric made of a bonded composite staple fiber, which can be easily peeled off to form an ultrafine fiber, and a polymer elastic material.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a cross section of a bonded conjugate fiber used in the method of the present invention.

[Explanation of symbols]

 1: Component A 2: Component B

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Yoshihiro Tanba 1621 Sazu, Kurashiki-shi, Okayama Prefecture F-term (reference) 4F055 AA02 AA13 AA15 AA21 AA27 AA30 BA02 DA07 EA04 EA05 EA13 EA14 EA24 EA34 FA10 FA15 GA03 HA04 4L041 AA07 BA04 BA05 BA11 BA34 BA49 BA59 BD11 BD15 CA12 CA21 CA25 CA44 DD01 DD06 DD14 EE01 EE15 EE20 4L047 AA21 AA23 AA27 AB02 BA03 CA08 CC02 CC06 CC09 DA00

Claims (1)

[Claims] 1. The following steps (1) to (3) are performed by (1) →
(2) → (3) or (1) → (3) → (2) in this order. (1) In the cross-section of the fiber, in a bonded composite staple fiber having a structure in which two types of polymer components A and B are alternately arranged, A is 0.5% to 7.0 of the dicarboxylic acid component.
% Copolymerized polyethylene terephthalate modified with 5-sodium sulfoisophthalic acid in the range of
B has a solubility parameter (SP value) of 10.0 to 15.
0: a process for producing a nonwoven fabric from a bonded composite staple fiber in which the weight ratio of both polymers A and B is in the range of 90/10 to 10/90. Step of providing a molecular elastic body (3) Step of peeling off the joint between polymer A and polymer B using an aqueous solution of sodium hydroxide or potassium hydroxide having a concentration of 0.3 mol / l or less.