JPH04202861A - Flexible fibrous sheet and polyurethane-based multicomponent yarn suitable for production thereof - Google Patents

Abstract

PURPOSE:To obtain a flexible fibrous sheet having high strength by adding a thermoplastic polyurethane containing a silicone segment in a main chain and/or a side chain in a porous state to nonwoven fabric comprising bundled yarn of ultrathin fibers. CONSTITUTION:Sea island type or multi-core sheath core type polyurethane multicomponent yarn comprising a thermoplastic polyurethane containing a silicone segment in a main chain and/or a side chain as a dispersion medium component and another thermoplastic polymer (e.g. polyamide or polyester) incompatible with the polyurethane as a dispersion component is used to give interlaced nonwoven fabric. Then the polyurethane in the multicomponent yarn is dissolved by using a solvent which is a solvent for the polyurethane and is a non-solvent for the other component or by impregnating the fabric with a solution of the same polyurethane or a different polyurethane and coagulated in water to give a finely porous flexible fibrous sheet.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a flexible fibrous sheet containing porous polyurethane in an ultrafine nonwoven fabric, and a multicomponent fiber containing polyurethane as one component suitable for the production thereof.

[Conventional technology]

Conventionally, leather-like sheet materials made of ultrafine fiber nonwoven fabric and elastomer have been highly evaluated as having a texture similar to natural leather, such as being more flexible and with excellent folding texture compared to nonwoven fabrics made of denier fibers. It has been. A method for manufacturing such a leather-like sheet material is to treat a nonwoven fabric made of ultrafine fibers with a solvent or the like before or after impregnating it with an elastomer to remove one of the fiber components.
A method of producing a fibrous sheet made of ultrafine fibers and an elastomer by dissolving or decomposing components has been widely used. According to this manufacturing method, products with various textures can be easily manufactured, but on the other hand, the process is complicated because a part of the fiber components are extracted and removed, and there is a lot of waste in terms of resources. On the other hand, a fibrous sheet is manufactured by using an elastomer as one component of the microfiber-generating fiber, impregnating it with an elastomer solvent or solution, dissolving the elastomer, and coagulating it into a porous structure in a nonwoven fabric without extracting and removing it. Many proposals have also been made. For example, in the production of polyurethane multicomponent fibers made of thermoplastic polyurethane and inelastic polymers, or leather-like sheet materials from such multicomponent fibers, for example, polyamides such as 11-nylon and polyurethane are melt-mixed and spun. Japanese Patent Publication No. 40-2792 discloses that the mixed fibers obtained are made into a nonwoven fabric and processed to make a leather-like sheet material. Japanese Patent Laid-Open No. 52-57303 discloses that polyurethane and polyethylene or polystyrene are melt-spun to form a mixed fiber, and the mixed fiber is mixed with other microfiber-generating fibers. Japanese Unexamined Patent Publications No. 59-211664, No. 59-211666, and No. 63-1274 disclose fiber-entangled nonwoven fabrics, which are processed into fibrous sheets.
4 and JP-A No. 2-14056, a multi-component fiber made by combining a thermoplastic polyurethane with a specific melt flow rate and a polymer mainly composed of polyolefin or polystyrene is disclosed in JP-A No. 60-45611 and JP-A-Sho 2-14056. Publication No. 60-126322, JP 64-5282
In Publication No. 0, the terminal amine group concentration is 3xlO-'eq/g.
JP-A-60-126359 discloses that a non-woven fabric of mixed fibers of polyamide and thermoplastic polyurethane sealed below is processed to make a fiber sheet, and the core component is polyurethane and the sheath component is an island phase and soluble polymer of inelastic polymer. A core-sheath type composite fiber having a sea-island phase consisting of a polymer blood phase, in which a large number of inelastic polymer ultrafine fibers are present around polyurethane fine fibers by dissolving and removing a soluble polymer, is produced in JP-A-61. In JP-A No. 194247, a polyurethane multicomponent fiber using polyester urethane as a specific component is disclosed in JP-A-62-21820, in which polyethylene, polypropylene, etc. are melt-kneaded and thermoplastic polyurethane is spun to form fibrils. A multi-component filament to be formed has already been proposed in Japanese Patent Laid-Open No. 73514/1983. In addition, a split type multiphase structural fiber in which polyurethane and an inelastic polymer are bonded in multiple phases is disclosed in Japanese Patent Application Laid-Open No. 48-28002,
Japanese Patent Laid-Open No. 52-85575 discloses that a fiber sheet is formed using a seabird-type composite fiber that generates ultrafine fibers made of an inelastic polymer and ultrafine fibers made of an elastic polymer. Proposed. Furthermore, in the production of polyurethane elastic fibers, it is also known to add incyanate compositions, polysiloxanes, etc. to polyurethane during melt spinning.

[Problem to be solved by the invention]

Making a fibrous sheet made of ultrafine fibers and porous polyurethane using polyurethane multicomponent fibers simplifies the process because it does not involve the extraction and removal process of fiber components.
Moreover, it is an excellent method that does not waste resources, and although many proposals have been made as described above, it has not yet been put into practical use. The biggest reason for this is that it is difficult to spin such fibers stably for long periods of time, and even if the fibers can be spun stably, they cannot be processed into nonwoven fabrics and impregnated with a polyurethane solvent or solution and coagulated. This is because the polyurethane in the multicomponent fiber did not become sufficiently porous, and the flexibility of the ultrafine fiber could not be obtained. In other words, the conventional manufacturing methods for polyurethane multicomponent fibers containing polyurethane as one component are: (1) mixing thermoplastic polyurethane and non-elastic polymer as spinning raw materials and melt-spinning; (2) mixing thermoplastic polyurethane and non-elastic polymer, respectively. A method of melting in different melting systems and forming a mixed system by static mixing or dynamic mixing of the re-melted product at the spinning head and spinning, or This method involves melting in a melting system, controlling the solid melt with a nozzle, integrating each melt into a multicore core-sheath type, and performing composite spinning. Among these melt spinning methods, spinning through a melt mixing system■
In the spinning method (2), it is difficult to stabilize the fiber phase and perform stable continuous spinning for a long time with few occurrences of screws and yarn breakage, except for the combination of thermoplastic polyurethane and a specific inelastic polymer. Even with the spinning method (2), although the spinning method is stable during short-time spinning, when spinning continuously for a long time, deposits occur around the thermoplastic polyurethane nozzle, the fiber phase becomes unstable, and screws and yarn breakage occur frequently. Become. In particular, it is good when the inelastic polymer combined with polyurethane has an affinity with polyurethane or is a polymer that undergoes an exchange reaction under spinning conditions, such as a polymer such as polyamide or polyester, or a water-absorbing/hygroscopic polymer. Not only the formation of a fibrous phase but also the spinnability is impaired. In particular, when producing polyurethane multicomponent fibers in which a fiber phase is formed using an inelastic polymer as a multicore dispersed component and polyurethane as a dispersion medium component, the dispersed components of the inelastic polymer are formed as a relatively uniform circular cross section. It was difficult to perform continuous spinning for a long time. In particular, in the case of a polymer that undergoes an exchange reaction under the above-mentioned spinning conditions, separation of the inelastic polymer and polyurethane using a polyurethane solvent is not stable due to the degree of interfacial reaction. Even if a fiber aggregate is made using the polyurethane multicomponent fiber obtained in this way, and then impregnated with a polyurethane solvent to dissolve the polyurethane in the mixed spun fiber, the inelastic polymer and polyurethane cannot be combined for the above-mentioned reasons. The separation of the substrate is insufficient and uneven, and even if the substrate is introduced into a coagulation bath, then washed and dried, a strong and flexible 1
It was difficult to produce a 11M quality sheet. The first object of the present invention is to provide a polyurethane multicomponent fiber containing polyurethane as a dispersion medium component and an inelastic polymer as a dispersion component, the multicomponent fiber having a uniform cross-sectional shape with a fiber phase. . The second method is to use polyester or polyamide, which could not be stably spun in the past.
It is an object of the present invention to provide a multicomponent fiber in which the phase of each constituent component is stable even when used as a component, and the inelastic polymer and polyurethane can be easily separated by a polyurethane solvent. Furthermore, it is an object to stably produce a flexible fibrous sheet with high strength using the fibers.

[Means to solve the problem]

The present invention is a fibrous sheet in which polyurethane is contained porously in a nonwoven fabric made of bundled fibers of ultrafine fibers, wherein the porous polyurethane contained in at least the inside of the ultrafine fiber bundle has a main chain and/or A flexible fibrous sheet characterized by containing thermoplastic polyurethane having silicone segments in side chains. The present invention also provides polyurethane-based multicomponent fibers or polyurethane-based multicomponent fibers in which a thermoplastic polyurethane having a silicone segment in the main chain and/or side chain is used as a dispersion medium component, and a thermoplastic polymer that is incompatible with the polyurethane is used as a dispersion component. A fiber aggregate is made from the fibers, and then impregnated with a solvent of the polyurethane component and a non-solvent of the other components, or a solution of a polyurethane that is the same as or different from the polyurethane, and the polyurethane in the multicomponent fiber is This is a method for producing a flexible fibrous sheet, which is characterized by dissolving the substrate and introducing the substrate into a coagulation bath, followed by washing with water and drying. Furthermore, the present invention provides a polyurethane characterized in that a thermoplastic polyurethane having a silicone segment in its main chain and/or side chain is used as a dispersion medium component, and a thermoplastic polymer that is incompatible with the polyurethane is used as a dispersion component. It is a multi-component fiber. The thermoplastic polyurethane constituting the multicomponent fiber of the present invention is a silicone compound having a reactive organic functional group or an intermediate containing the silicone compound, a polymer diol,
It is a thermoplastic polyurethane obtained by reacting raw materials mainly consisting of four components: an organic diisocyanate and a low-molecular compound having two active hydrogen atoms. A preferable polyurethane forming a dispersion medium phase in the fiber has an intrinsic viscosity [V] of 0.7 when dissolved in an N,N-dimethylformamide solvent.
-1.8, the amount of hard segments excluding silicone segments in the polyurethane is 30 to 60% by weight when a diol compound or a hydroxyamine compound is used as a chain extender,
More preferably, it is in the range of 35 to 50% by weight, and in the case of using an amine compound as the chain extender, it is in the range of 20 to 40% by weight. Thermoplastic polyurethanes outside these ranges do not have the melt viscosity to form the desired fibrous phase, and the fibrous phase may become inverted or unclear, or spinnability may be impaired. Preferred examples of the silicone compound having a reactive organic functional group include the following compounds. (l) Amino-modified silicone oil (2) Epoxy-modified silicone oil (3) Alcohol-modified silicone oil (m = 0 to 6
3) (4) Mercapto-modified silicone oil (m=1 to 6
4. R-lower alkyl group) (5) Carboxyl-modified silicone oil The silicone compounds having reactive organic functional groups as described above are examples of preferred silicone compounds in the present invention, and the present invention is not limited to these examples. However, the above-mentioned exemplified compounds and other silicone compounds are currently commercially available and can be easily obtained from the market, and any of them can be used in the present invention. Furthermore, when the reactive group of the silicone compound is a hydroxyl group, an amino group, a carboxyl group, an epoxy group, etc., a polyester polyol obtained by reacting with a polymer diol, a chain extender, or a polyvalent carboxylic acid or a polyvalent amine, which will be described later. , polyamide polyamine, polyether polyol, etc. can be used in the same manner. Any polyurethane resin containing a silicone compound obtained from the above-mentioned materials can be used in the present invention, but preferred are those in which the silicon atom content is 0.1 to 4% by weight based on the total amount of the polyurethane resin. If the amount of the silicone compound is less than 0.1%, it will be insufficient to achieve the intended purpose of the present invention, and if the amount exceeds 4% by weight, the polymerizability and spinnability will become unstable, which is not preferable. Polymer diols constituting the soft segment of thermoplastic polyurethane include, for example, polyethylene adipate,
Polyester diols obtained by reacting low-molecular-weight diols with dicarboxylic acids, such as polyethylene propylene adipate, polybutylene adipate, polyhexamethylene adipate, poly-3-methyl-1,5-pentane adipate, polynonane adipate, etc. , polylactone diols such as polycaprolactone diol, polycarbonate diols such as polyhexamethylene carbonate diol, polyether glycols such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, etc. At least one type of polymer diol selected from glycol, polyether polyester block copolymer glycol, and the like. Further, the organic diincyanates constituting the hard segment include tolylene diisocyanate, xylylene diisocyanate, aromatic diisocyanates such as 4,4'-diphenylmethafdiiso/anate, 4,4'-dicyclohexylmethane diisocyanate, At least one type of organic diisocyanate selected from aliphatic diisocyanates such as inphorone diisocyanate, naphthalene diisocyanate, and the like. Examples of chain extenders include diols such as ethylene glycol, butylene glycol, hexamethylene glycol, and 3-methyl-1,5-bentanediol, ethylene diamine, hexamethylene diamine, 4,4'-dicyclohexylmethane diamine, and inphorone diamine. It is at least one type of compound selected from diamines and the like. On the other hand, inelastic polymers are selected from, for example, polyamides, polyesters, polyesteramides, etc. with a melting temperature of 1
Poly measured at 60-250°C5 spinning temperature-
It is a thermoplastic polymer whose melt flow rate (hereinafter referred to as MFR) value is smaller than the MFR value of thermoplastic polyurethane. Examples of this polyamide include 6-nylon, 6/10-nylon, 10/9-nylon, and 10/9-nylon.
10-nylon, 11 nylon, 12 nylon, 6.6
Examples include polyamides selected from /6-nylon, 6.12-nylon, etc., preferably with a terminal amino group concentration of 3
x 1.0-”eq/g or less, more preferably 1.5
By using a polyamide of x 10-'eq/g or less, stable spinning can be achieved. Examples of the polyester include polyesters selected from polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene terephthalate copolymers, polyester/polyamide block copolymers, and the like. Next, the polyurethane multicomponent fiber can be produced by spinning according to a conventionally known melt spinning method. In other words, one melt system melts a thermoplastic polyurethane having silicone segments in its main chain and/or side chains, the other melt system melts an inelastic polymer, and the respective melts are statically mixed at the spinning head. 1. Melt a thermoplastic polyurethane having silicone segments in its main chain and/or side chains in one melt system, and melt an inelastic polymer in the other melt system. , the polyurethane melt is made into a sheath component (or sea component) using a nozzle, and the inelastic polymer melt is regulated into a multi-core core component (or island component) and integrated into a multi-core core-sheath type. It is then carried out using a composite spinning method. In particular, the present invention shows high effects in the spinning method (2). The spinning temperature varies depending on the thermal behavior of the thermoplastic polyurethane used, such as the melt flow temperature and thermal dissociation temperature, and the melt flow temperature of the inelastic polymer, but is preferably in the range of 220 to 260°C. If the spinning temperature is outside this range, unfavorable conditions may occur in the polyurethane, or a stable fiber phase may not be formed, making stable spinning impossible. The composition ratio of the polyurethane dispersion medium component and the inelastic polymer dispersion component is determined depending on the intended use of the fiber, but the polyurethane dispersion medium component is in the range of 10 to 60% by weight in view of the stability of the fiber phase. The fiber cross-sectional shape of the polyurethane multicomponent fiber obtained by the spinning of the present invention is approximately circular or elliptical (
A large number of dispersed components (core components) of a rounded rectangle
, is a multicore sheath type composite fiber (or seabird type fiber) in which polyurethane is the dispersion medium component (sheath component). This multicomponent fiber is produced by wet-heat stretching or dry-heat stretching.
The fibers are stretched twice and heat-set and mechanically crimped as necessary to obtain the fibers to be used. The multicomponent fibers are cross-wrap webs or random webs, with the required weight depending on the intended product orientation, but usually between 100 and 2000 g/m@2. The fiber entangled nonwoven fabric is then formed by needle punching or high-speed fluid flow treatment. It may also be a woven fabric, a knitted fabric, or a raised fabric of these fabrics. After making these fiber aggregates, they are treated with a commonly used solvent for the polyurethane component constituting the fibers, such as N,N-dimethylformamide, dimethyl sulfoxide, and tetrahydro-7rane. Or a part of the polyurethane that makes up the fiber is treated with a solution containing the same or different polyurethane as the polyurethane that makes up the fiber, with colorants, activators, fillers, and other additives added as necessary. Alternatively, a fibrous sheet material is obtained by melting the entire material, retaining the melt in the fiber aggregate, and wet-coagulating it. The surface of the obtained fibrous sheet material can be finished with raised fibers to create suede-like artificial leather, or a coating layer can be added to the surface. It may be made into silver-stamped artificial leather by smoothing or simply smoothing and finishing with a colored finishing layer. The fibrous sheet material obtained by the method of the present invention has better separation of inelastic polymer fibers and polyurethane sponge than fibrous sheet materials made by the same conventional method, and has a texture similar to natural leather. It is a fibrous sheet material with markedly improved physical properties such as tensile cutting strength, tear strength, creep, and elongation elastic recovery.

【Example】

Next, embodiments of the present invention will be explained with specific examples. Note that parts and percentages in the examples are by weight unless otherwise specified. Examples 1 and 2, Comparative Examples 1 and 2 The average of the following formula [1] was added to a polyester diol (hereinafter referred to as PMPA) with an average molecular weight of 1500 consisting of 3-methyl-1,5-bentanediol and adipic acid. molecular weight is 1
500 dimethylsiloxane polyol (m is the value that makes the molecular weight 1500) (A), the silicon content ratio in the total amount of polyurethane resin is 0.3% (B)
), 2.5% (C) and 5.0% (D) of polymer diol, l,4-butanediol (hereinafter referred to as BD) and 4,4'-diphenylmethane diisocyanate (hereinafter referred to as MDI) ) by melt polymerization from
Four types of thermoplastic polyurethane pellets were obtained having a weight percent nitrogen attributable to MDI of 4.0%. Polyurethanes (B), (C) and (D) are thermoplastic polyurethanes having polysiloxane groups in their side chains. Table 1 shows the blending ratio of polyurethane. (Leaving space below) Table 1 Using the thermoplastic polyurethane pellets obtained in this way as a spinning raw material, the polymer flows melted in two extruder melt systems are combined at the spinning head, and the division and integration process is repeated. Using a multi-component fiber manufacturing apparatus that forms a mixed flow using a conventional mixing method and performs melt spinning, the polyurethane with a moisture content of 65 PPM was charged into one melt system in a dry nitrogen gas atmosphere, and the polyurethane was melted at a melt zone temperature of 250°C. , 6-nylon with a terminal amino group concentration of 1.1 x 10-'eq/g and a moisture content of 70 PPM was charged into the other melt system, and the melt zone temperature was set to 25.
Melt at 0°C, measure each melt stream with a metering pump, merge 20 parts of polyurethane flow and 80 parts of 6-nylon flow at the spinning head, spinning temperature 250°C, winding speed 700 m/ra. In was spun to produce a 10 denier composite fiber. At that time, spinning stability, state of the fiber phase, yarn physical properties, and N,N-dimethylformamide (hereinafter referred to as D
The solubility in MF (referred to as MF) was evaluated (Table 2). That is, in Examples 1 and 2, almost stable spinning was possible, fibers with high yarn physical properties, good dispersed phase of fibers, and good separation of fine fibers when treated with DMF were obtained. On the other hand, in Comparative Example 1 in which dimethylsiloxane polyol was not added, there were many occurrences of screws and yarn breakage, the fiber shape was non-uniform, and stable spinning could not be achieved. Furthermore, when the spinning pack was disassembled, many brown scales were found inside the spinning pack. On the other hand, in the case of Comparative Example 2, in which dimethylsiloxane polyol was mixed so that the silicon content ratio in the total amount of polyurethane resin was 5.0%, the occurrence of screws and yarn breakage increased, and the fiber shape was irregular. Became. (Margins below) Table 2 Ratio evaluation symbol of silicon atoms in the total amount of polyurethane resin ◎ Excellent, ○ Good, ×: Bad. The obtained multicomponent fiber was drawn three times in hot water at 80°C and heat-set to obtain a fiber with a fineness of 3.5 dr. After applying an oil agent to this fiber, it was mechanically crimped and cut into fiber lengths of 5 mm to obtain staple fibers. Each stable fiber was then passed through a card, random univer, and laminated by a cross-lap method to an average weight of 450 g.
/ m ” fiber web, then needle punched from both sides of the fiber web at a total punch density of 980 punches/m2 to obtain a fiber entangled nonwoven fabric, which was coated with 5% polyvinyl alcohol.
After impregnating with an aqueous solution, squeezing at a target squeezing rate of 150%, and drying to obtain a nonwoven fabric with a stable shape, 2-methyl-1,8-
A polyester diol with an average molecular weight of 2,000 obtained by condensing a mixture of octanediol and 1.9-nonanediol (molar ratio 50/50) with adipic acid and a polyethylene glycol with an average molecular weight of 2,000 (mixing ratio, 85: 15) ) /MD 1/ Polyurethane with a nitrogen content of 3.5% consisting of ethylene glycol at a concentration of 10
%l = impregnated with the adjusted DMF solution at an impregnation rate of 200%,
The polyurethane in the fibers was dissolved in an atmosphere at a temperature of 45°C. The polyurethane was then coagulated by immersion in a 30% DMF aqueous solution and treated in hot water at 95°C to remove the solvent and polyvinyl alcohol. One side of the obtained fibrous sheet was sliced to a thickness of 1.0 mm, and the surface side upon coagulation was subjected to a napping treatment to create a suede-like sheet, which was then dyed and rubbed to obtain a product. Its performance is shown in Table 3. Table 3 *Ratio evaluation symbols of silicon atoms in the total amount of polyurethane resin ◎・Excellent, O8 good, X・poor. The product of the example had good heat fixability when ironed, had a firm and flexible texture with little shedding of fuzz, and was excellent as a suede-like sheet. Furthermore, when the fibrous sheets were observed using scanning electron micrographs, the nylon ultrafine fiber bundles and polyurethane sponge were well separated in the fibrous sheets of Examples 1 and 2, and the fibers of Comparative Example 1 Separation of the quality sheet was insufficient and the polyurethane sponge was wrapped around the nylon. Examples 3 and 4, Comparative Examples 3 and 4 Thermoplastic polyurethane pellets (A
), (B) and (C), when spinning dimethylsiloxane polyol [1] into polyurethane noheret (A), add and knead so that the ratio is the same as the ratio of dimethylsiloxane polyol [1] in polyurethane (B). Then, 50 parts of the polyurethane flow and 50 parts of the polybutylene terephthalate flow were combined at the spinning head, and the spinning temperature was 250'.
Spinning at O1 winding speed of 700 m/min, 12
Manufactured denier composite fiber. The results are shown in Table-4. Table 4 shows that when the polyurethane of the present invention is spun, the yarn physical properties are high, the dispersed phase of the fiber is good, and DMF
It can be seen that fibers with good separation properties of fine fibers can be stably obtained when treated with. However, it can be seen that even if a silicone compound that has not been converted into polyurethane is added, the effect is small. * Ratio evaluation symbol of silicon atoms in the total amount of polyurethane resin ◎: Excellent, O: Good, ×: Bad. The obtained multicomponent fibers were treated in the same manner as in Example 1, mechanically crimped to form staple fibers with a fineness of 4 dr and a fiber length of 51+ nm, passed through carding and random univar to form a fiber web, and cross-wrapped to form staple fibers. After laminating, needle punching is performed on both sides, followed by water pressure of 70°C from one side.
kg/cm'' high-pressure columnar water stream and dried to obtain a fiber-entangled nonwoven fabric with an average weight of 720 g/+n'. DM in which water-soluble silicone was added to this nonwoven fabric.
The nonwoven fabric was impregnated with F at a target impregnation rate of 200% and placed on a polyethylene belt in an atmosphere of 55° C. for about 2 minutes, and then immersed in a DMF aqueous solution to coagulate the eluted polyurethane into the nonwoven fabric. The water-treated surface of the obtained fibrous sheet was 135
After smoothing the surface by pressing it against a smooth metal belt surface heated to ℃, a colored layer of polyurethane mainly made of polycarbonate polyurethane and a resin layer are applied to the surface, and an embossing roll with a calf-like pattern is applied. It was patterned and made into a leather-like sheet. The physical properties of the obtained sheet material are shown in Table 5. In other words, the product of the example is strong and flexible with the elasticity that resembles leather, and it has a 10% elongation in both the vertical and horizontal directions, and has a surface that can be seen by the change in gloss that occurs on the surface when it is pasted on a kamaboko-shaped wooden mold. Irregularity (also called fishing moro or orange peel) was judged to be excellent in grade 2. However, Comparative Examples 38 and 4
The product has a uneven texture, and when folded, creases occur in streaks, which does not look good. Furthermore, in the fishing evaluation, large irregularities were noticeable and the product was evaluated as a 4.5 grade, which was poor. Ratio evaluation symbol of silicon atoms in the total amount of polyurethane resin ◎: Excellent, ○: Good, X: Bad. Examples 5 and 6, Comparative Examples 5 and 6 Polybutylene adipate (hereinafter referred to as PBA) with an average molecular weight of 1,000 and alcohol-modified polysiloxane of the following formula [2] with an average molecular weight of 2,000 CHs CHs CH
s (n is the value at which the molecular weight is 2000) (E), and polymer diol (F) mixed so that the silicon content ratio in the total amount of polyurethane resin is 2.0%.
), BD and MDI were melt-polymerized to obtain four types of thermoplastic polyurethane pellets with a nitrogen weight percent attributable to MDI of 4.0%. Table 6 shows the blending ratio of polyurethane. On the other hand, polytetramethylene glycol (hereinafter referred to as PTMG) with an average molecular weight of 1000 and alcohol-modified polysiloxane-free product (G) of the following formula [2], the silicon content ratio in the total amount of polyurethane resin is 2.0%. Polymer diol (H), BD and MD mixed so that
After melt polymerization from I, the weight percent of nitrogen attributable to MDI is 4.
．． Four 5% thermoplastic polyurethane pellets were obtained. Table 6 shows the blending ratio of polyurethane. Polyurethanes (F) and (H) are thermoplastic polyurethanes having polysiloxane groups in their main chains. The thermoplastic polyurethane pellets obtained in this manner were spun into w size to produce a polyurethane multicomponent fiber containing 6-nylon as a dispersion medium component in the same manner as in Example-1.
The spinning stability, state of the fiber phase, yarn physical properties, and solubility in DMF were evaluated (Table 7). That is, in Examples 5 and 6 of polyurethanes having a polysiloxane group in the main chain, as in Examples 1 and 2 of polyurethanes having a polysiloxane group in the side chain, very stable spinning was possible, and the yarn physical properties were improved. Fibers were obtained that had a high fiber content, a good dispersed phase of the fibers, and good separation of fine fibers when treated with DMF. It l
On the other hand, in Comparative Examples 5 and 6 in which no alcohol-modified polysiloxane compound was added, there were many occurrences of screws and yarn breakage, the fiber shape was non-uniform, and stable spinning could not be achieved. Furthermore, when the spinning pack was disassembled, many brown scales were found inside the spinning pack. Ratio of silicon atoms in the total amount of polyurethane resin Evaluation symbol: ◎6 Excellent, O Good, × Bad. Using the obtained multicomponent fiber, it was processed in the same manner as in Example 1 to finish it into a suede-like sheet, which was then dyed and rubbed to produce a product. Its performance is shown in Table 8. The product of the example had a firm and flexible texture and was excellent as a suede-like sheet, but the product of the comparative example had a paper-like feel with less volume. Furthermore, when the fibrous sheets were observed using scanning electron micrographs, the nylon ultrafine fiber bundles and the polyurethane sponge were well separated in the fibrous sheets of Examples 5 and 6, and Comparative Examples 5 and 6 The fibrous sheet was not separated enough and the polyurethane sponge was stuck around the nylon. (Margin below) Table 8 Ratio evaluation symbol of silicon atoms in the total amount of polyurethane resin ◎: Excellent, O good, X, poor.

【Effect of the invention】

In the production of polyurethane-based multicomponent fibers, the present invention uses thermoplastic polyurethane having silicone segments in the main chain and/or side chains as a dispersion medium component, thereby producing polyesters, polyamides, etc. that have an affinity for polyurethane. In the case of polyurethane-based multicomponent fibers containing polymers as dispersed components, there is less occurrence of screws and nozzle fouling, and the fiber phase is stabilized, resulting in less yarn breakage and stable continuous spinning for long periods of time. Furthermore, the obtained multicomponent fiber has less sticking and has good crimp stability. Also,
This multicomponent fiber has good separability with polyurethane solvents such as N,N-dimethylformamide, and a fiber aggregate is made using this polyurethane multicomponent fiber and impregnated with a polyurethane solvent or a solution containing polyurethane. ,
By dissolving the polyurethane in the multicomponent fibers and then wet coagulating, a flexible amyl-like shish is obtained. Furthermore, since the polyurethane can be eluted from the multicomponent fibers with a solvent and the eluted polyurethane can be re-solidified before use, it is possible to rationalize the production of fibrous sheets and also help save resources. Patent applicant: Rira Co., Ltd. Agent: Ken Honda, patent attorney

Claims (1)

[Scope of Claims] (l) A fibrous sheet in which polyurethane is contained porously in a nonwoven fabric made of bundles of ultrafine fibers, wherein at least the porous polyurethane contained inside the bundle of ultrafine fibers is A flexible fibrous sheet comprising thermoplastic polyurethane having silicone segments in its main chain and/or side chains. (2) A polyurethane multicomponent fiber whose dispersion medium component is a thermoplastic polyurethane having a silicone segment in its main chain and/or side chain, and whose dispersion component is a thermoplastic polymer that is incompatible with the polyurethane; A fiber aggregate is made from the multicomponent fibers, and then impregnated with a solvent that is a solvent for the polyurethane component and a non-solvent for the other components, or a solution of a polyurethane that is the same as or different from the polyurethane to dissolve the polyurethane in the multicomponent fiber. A method for producing a flexible fibrous sheet, which comprises introducing a substrate into a coagulation bath, followed by washing with water and drying. (3) A polyurethane multicomponent fiber characterized in that the dispersion medium component is a thermoplastic polyurethane having a silicone segment in the main chain and/or side chain, and the dispersion component is a thermoplastic polymer that is incompatible with the polyurethane. .