JP4914794B2 - Method for producing core-sheath type composite fiber containing polycarbonate - Google Patents

Description

The present invention relates to a method for producing a core-sheath type composite fiber having a fineness and containing polycarbonate.

  Polycarbonate resins are used in large quantities as engineering plastics. Fibers using polycarbonate have been proposed in various configurations so far, and they are also used for special applications such as optical fibers, taking advantage of excellent transparency.

  For example, Patent Document 1 discloses that a polycarbonate single fiber having excellent fiber performance can be obtained by spinning polycarbonate into fibers by melt spinning, and orienting the fibers by heating and stretching the fibers. Has been. This fiber is said to be usable as a textile, clothing, or industrial fiber.

  Patent Document 2 discloses a composite fiber in which a component made of polycarbonate and a component made of elastomeric polyurethane are bonded along their lengths. The purpose of this fiber is to obtain a helically crimped two-component textile filament and a textile product made therefrom.

  Patent Document 3 discloses a polycarbonate fiber in which ultrafine fibers made of a polypropylene component are dispersed and arranged in a bundle in a polycarbonate component. This fiber is obtained by adding polypropylene to polycarbonate at the pellet stage, uniformly mixing and melting, melt spinning, and blocking the propagation of crazes (orientation) generated in the polycarbonate component, or generation of crazes. The effect which prevents this is produced | generated, and there exists an effect | action and effect which suppress the embrittlement of a polycarbonate fiber.

  Patent Document 4 discloses a core-sheath type composite fiber in which a core part includes a thermoplastic polymer and a sheath part includes a polyolefin. This fiber has good compatibility with the core component and the sheath component, and also has good compatibility with an elastic composition such as a rubber composition, and can be suitably used for reinforcing an elastic material.

Patent Document 5 discloses a nonwoven fabric in which a polycarbonate is melt-spun from a spinning hole and at the same time, a high-temperature and high-speed gas is jetted from an adjacent gas discharge hole to form an ultrafine fiber flow and collected in a sheet shape.
Japanese Patent Publication No. 37-018328 Japanese Patent Publication No. 48-013730 Japanese Patent Laid-Open No. 51-072610 JP 2003-193332 A JP-A-5-279947

  As a single component fiber using polycarbonate, for example, Patent Document 1 discloses a polycarbonate fiber having a fineness of 75 denier. Patent Document 2 discloses a method for producing a core-sheath type composite fiber or a parallel type composite fiber of polycarbonate having a fineness of 105 denier and elastomeric polyurethane. Patent Document 3 discloses a sea-island structure fiber in which polycarbonate and polyolefin are mixed. Cited Document 4 discloses, as an example of a core-sheath type composite fiber composed of a thermoplastic polymer and a polyolefin, a core-sheath type composite fiber having polycarbonate as a core component and polyolefin as a sheath component is disclosed. It does not show a problem in production and a specific method for producing a polycarbonate core-sheath type composite fiber having a fineness. Citation 5 discloses a long-fiber nonwoven fabric made of polycarbonate fibers having an average fiber diameter of 12 microns or less by melt blowing.

  As described above, various studies have been made on polycarbonate fibers, and single fibers and composite fibers of polycarbonate have been proposed. However, fine fibers used for non-woven fabrics using polycarbonate have not been put to practical use until now. The reason is that the polycarbonate component tends to become brittle immediately after spinning, yarn breakage is likely to occur, and it is difficult to obtain fine fibers. Further, according to the so-called melt blown method in which high-temperature and high-speed gas is ejected simultaneously from adjacent gas discharge holes as in Patent Document 5, fineness can be reduced, but generally obtained nonwoven fabric has low strength and uses There was a problem of being limited.

In order to solve the above-mentioned conventional problems, the present invention provides a method for stably producing a core-sheath type composite fiber containing a polycarbonate having a fineness.

The manufacturing method of the core-sheath type composite fiber containing the polycarbonate of the present invention is a method in which a heated and melted polycarbonate and a thermoplastic polymer are placed in a gas atmosphere having an ambient temperature of 35 ° C. or more and less than the glass transition point of the polycarbonate from a nozzle outlet. Spinning and obtaining an unstretched filament composed of a core-sheath composite fiber having a component containing 50% by mass or more of polycarbonate as a core component and a component containing 50% by mass or more of a thermoplastic polymer as a sheath component .

  In the present invention, the heated and melted polycarbonate is spun into a warm air atmosphere at a temperature of 35 ° C. or more and less than the glass transition point of the polycarbonate from a nozzle discharge port, thereby forming a fiber. By slowing the cooling of the polymer, a polycarbonate fiber having a relatively fineness can be obtained. By mitigating the temperature drop of the polycarbonate component immediately after spinning, the embrittlement phenomenon peculiar to polycarbonate fibers is suppressed, and yarn breakage hardly occurs. That is, the embrittlement phenomenon peculiar to the polycarbonate fiber is suppressed by slowing the cooling of the polymer immediately after spinning in which the fiber is formed and relaxing the cooling rate.

  In general, a polyester fiber or a polyolefin fiber is spun from a nozzle discharge port into an atmosphere of about 10 to 25 ° C., and the filament is taken up. This is to prevent the filaments from fusing immediately after spinning. However, as with polyester fibers and polyolefin fibers, if the spinning filament is spun into an atmosphere of about 10 to 25 ° C. and the polycarbonate is made into a fiber, the polycarbonate component tends to become brittle immediately after spinning, and fibers with fineness cannot be obtained. It was. Therefore, the present inventor has studied a method for obtaining fine fibers containing a polycarbonate component of fine fineness, and if it is spun in an atmosphere blowing out a wind at a specific temperature, the embrittlement phenomenon can be suppressed. It was found that fine fibers containing the components can be obtained.

  In the method for producing a polycarbonate fiber of the present invention, a heated and melted polymer is spun from a nozzle outlet into an atmosphere in which the temperature can be maintained at 35 ° C. or more and below a glass transition point to form a filament. If a fiber containing at least a polycarbonate fiber component is produced by such a method, a fiber having a fineness of 0.1 to 20 dtex can be easily obtained. The heat-melted polymer of the present invention refers to a polymer in which components constituting the polycarbonate fiber are heat-melted, and the heat-melted polymer of the present invention preferably includes at least a component containing 50% by mass or more of polycarbonate. .

  The atmospheric temperature at which the polymer is spun is 35 ° C. or higher and lower than the glass transition point of the polycarbonate, the preferred lower limit is 40 ° C., and the preferred upper limit is a temperature that is 10 ° C. or more lower than the glass transition point of the polycarbonate. For example, when a general polycarbonate is used, the atmospheric temperature for spinning the polymer may be 35 ° C to 140 ° C. When a polymer melted by heating in an atmosphere of 35 ° C. or higher is spun, the polycarbonate component is difficult to cool, embrittlement can be suppressed, and the draft rate after spinning can be increased. Can be obtained. Further, if the atmospheric temperature is lower than the glass transition point, it has appropriate fluidity and spinnability is improved. Further, when the polycarbonate fiber is a core-sheath type composite fiber, it is preferable that the ambient temperature is 10 ° C. or lower than the fusion temperature of the sheath component from the viewpoint of fusion of the filaments. Here, the glass transition point is the glass transition temperature when the temperature is increased from −20 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min using a differential scanning calorimeter (DSC) for the resin before fiber production. Say.

  The atmosphere for spinning the polymer is a gas atmosphere, preferably a warm air atmosphere. The hot air is preferably blown from the upper side of the spinning cylinder at a wind speed of 1 to 3 m / min from the upper side of the spinning cylinder, and more preferably from the upper side of the chimney of the spinning cylinder. When the spinning atmosphere is a gas atmosphere, temperature control in the atmosphere is easy from the viewpoint of gas fluidity. Moreover, the take-up speed of the undrawn yarn when the polymer is spun can be appropriately selected within the range of 150 to 850 m / min.

Polycarbonate fibers of the present invention, Ru composite fiber der contain other components as a component. The polymer melted by heating may be a polymer containing at least a component containing 50% by mass or more of polycarbonate. That is, port polycarbonate fibers may be composite fibers, heated molten polymer may be a polymer containing a component with other components including polycarbonate least 50 mass%.

The polycarbonate fiber of the present invention preferably contains at least a component containing 50% by mass or more of polycarbonate, more preferably contains at least a component containing 60% by mass to 100% by mass of polycarbonate, and more preferably 70% by mass of polycarbonate. It contains at least a component containing ~ 100% by mass. When the polycarbonate content is 50% by mass or more in the component containing the polycarbonate, heat resistance and impact resistance are easily obtained, and the embrittlement phenomenon of the polycarbonate hardly occurs. A manufacturing method is preferred.

  The polycarbonate of the present invention has a melt flow rate (hereinafter also referred to as MFR) measured at 300 ° C. and a load of 11.76 N (1.2 kgf) according to JIS-K-7210 of 20 to 120 g / 10 min. The MFR of the more preferable polycarbonate is 50 to 80 g / 10 min. If the MFR of the polycarbonate is relatively high, the curing temperature is expected to decrease, and the embrittlement phenomenon can be further suppressed.

When the polycarbonate fiber of the present invention is a composite fiber containing other components as constituent components, the polycarbonate component may be mixed with other components in addition to the polycarbonate. As other components, for example, an olefin polymer such as polypropylene, polyethylene, polybutene, polymethylpentene, a polyester such as polyethylene terephthalate or polybutylene terephthalate, or a homopolymer or copolymer such as polyamide such as nylon 6 may be used. Good. Moreover, the polymer alloy of a polycarbonate and another component may be sufficient. Furthermore, you may add additives, such as a wax, an adhesive material, or a flame retardant, as needed. By mixing other components in addition to the polycarbonate, the melting or softening temperature can be arbitrarily adjusted.

  When mixing other components in addition to the polycarbonate, they can be mixed using a known mixing device. Known apparatuses are, for example, a Henschel mixer and a super mixer. Alternatively, it is convenient to melt-mix other components added as necessary to the polycarbonate using a known single-screw or twin-screw extruder or the like, and to make the first component into a master batch before fiberization.

Polycarbonate fibers of the present invention, a composite fiber comprising component and the other component comprising a polycarbonate least 50 mass%. The cross-sectional form of the conjugate fiber is, for example, a concentric, eccentric core-sheath type .

The polycarbonate fiber of the present invention may be a core-sheath type composite fiber having a component containing 50% by mass or more of polycarbonate as a core component and a component containing 50% by mass or more of a thermoplastic polymer as a sheath component. When the core component is a component containing polycarbonate and the sheath component is a component containing a thermoplastic polymer , a fine fiber can be obtained. This is presumably because the sheath component covers the polycarbonate of the core component, making the polycarbonate relatively difficult to cool and suppressing the embrittlement phenomenon.

  When the polycarbonate fiber is a core-sheath type composite fiber, the core component preferably contains 50% by mass or more of polycarbonate, more preferably the core component contains 60% by mass to 100% by mass of polycarbonate, and more preferably The core component contains 70% by mass to 100% by mass of polycarbonate. When the polycarbonate as a core component is 50% by mass or more, heat resistance and impact resistance are easily obtained, the embrittlement phenomenon of the polycarbonate is likely to occur, and the production method of the present invention is particularly suitable for obtaining fine fibers. It is.

  When the polycarbonate fiber is a core-sheath composite fiber, the sheath component preferably contains 50% by mass or more of the thermoplastic polymer, more preferably the sheath component contains 70% by mass to 100% by mass of the thermoplastic polymer. It is. When the thermoplastic polymer of the sheath component is 50% by mass or more, the sheath component has an effect of making it difficult to cool the polycarbonate of the core component. Examples of the thermoplastic polymer used as the sheath component include olefin polymers such as polypropylene, polyethylene, polybutene, and polymethylpentene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polylactic acid, nylon 6 1 or 2 or more can be selected from homopolymers or copolymers of polyamides such as Especially, it is preferable that a sheath component is a polyolefin-type polymer. When the sheath component is such a polymer, the effect of keeping the core component warm is more remarkable. Moreover, you may add additives, such as a wax, an adhesive material, or a flame retardant, as needed. When other components are mixed in addition to the thermoplastic polymer, the melting or softening temperature can be arbitrarily adjusted.

  Furthermore, when the polycarbonate fiber is a core-sheath composite fiber, the core / sheath composite ratio (volume ratio) is preferably 2: 8 to 8: 2, and more preferably the core / sheath composite ratio is 3: 7-7: 3, more preferably the core / sheath composite ratio is 4: 6-6: 4. If the core / sheath composite ratio is within this range, it is easy to obtain heat resistance and impact resistance due to the polycarbonate of the core component, and since there is a sufficient sheath component, the effect that the sheath component makes it difficult to cool the core component is also sufficient. Obtainable.

  When the polycarbonate fiber is a split-type composite fiber, the first component preferably contains 50% by mass or more of polycarbonate, more preferably, the first component contains 60% by mass to 100% by mass of polycarbonate. More preferably, the first component contains 70% by mass to 100% by mass of polycarbonate. When the polycarbonate of the first component is 50% by mass or more, heat resistance and impact resistance are easily obtained, the embrittlement phenomenon of the polycarbonate is likely to occur, and the production method of the present invention is particularly suitable for obtaining fine fibers. Is preferred.

  The polycarbonate fiber of the present invention can be used as an unstretched filament, but may be stretched. In the case of stretching, hot water may be used, or a heating pin or a heat roller may be used in an air atmosphere. The draw ratio is preferably 1 to 3 times.

  Hereinafter, the contents of the present invention will be specifically described with reference to examples.

[Softening point]
The resin before fiber production was measured according to JIS-K-6863.

[Glass transition point]
About the resin before fiber manufacture, the glass transition temperature when it heated up with the temperature increase rate of 10 degree-C / min from -20 degreeC using the differential scanning calorimeter (DSC) was made into the glass transition point.

(Sample 1 , Reference example )
A single fiber made of polycarbonate was produced. Polycarbonate having a glass transition point of about 145 ° C., a softening point of 240 ° C., a measurement temperature of 300 ° C. according to JIS-K-7210, and a melt flow rate of 70 g / 10 min at a measurement load of 11.76 N (1.2 kgf) Name: Novalex 7020A, manufactured by Mitsubishi Engineering Plastics Co., Ltd. was melted at a spinning temperature of 285 ° C. using a single nozzle, and a 45 ° C. hot air blowing atmosphere (wind speed: 2 m / min) from the nozzle outlet And undrawn filaments with a fineness of 11 dtex were obtained. During spinning, filament breakage was not observed and spinning was successful. Next, the unstretched filament was stretched 1.3 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 8.9 dtex.

(Sample 2)
A core-sheath type composite fiber having a fiber cross section, as shown in FIG. 1, comprising a core component and a sheath component was produced. As a core component, the glass transition point is about 145 ° C., the softening point is 240 ° C., the measurement temperature is 300 ° C. according to JIS-K-7210, and the melt flow rate at a measurement load of 11.76 N (1.2 kgf) is 70 g / 10 min. A certain polycarbonate (trade name: NOVAREX 7020A, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was prepared. As a sheath component, polyethylene having a melting point of 135 ° C., a measurement temperature of 190 ° C. as defined in JIS-K-6922-2, and a melt flow rate of 7 g / 10 min at a measurement load of 21.18 N (2.16 kgf) (trade name: HF560 and Nippon Polyethylene Co., Ltd.) were prepared. These two components are melted using a core-sheath type composite nozzle, the core / sheath composite ratio (volume ratio) is 5/5, the spinning temperature of the core component is 285 ° C., and the spinning temperature of the sheath component is 270 ° C. From the nozzle discharge port, spinning was performed in a warm air blowing atmosphere (wind speed: 2 m / min) at 40 ° C. and taken up at a speed of 750 m / min to obtain an unstretched filament having a fineness of 11 dtex. During spinning, no yarn breakage was observed, and spinning was successful. Next, the unstretched filament was stretched 1.4 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 8.9 dtex.

(Sample 3)
As a sheath component, an ethylene-propylene random copolymer having a melting point of 125 ° C., a measurement temperature of 230 ° C. as defined in JIS-K-7210, and a melt flow rate of 25 g / 10 min at a measurement load of 21.18 N (2.16 kgf) A core-sheath type composite fiber was obtained in the same manner as Sample 2, except that (trade name: Wintech (trade name), manufactured by Nippon Polypro Co., Ltd.) was used. The obtained fiber was an 11 dtex unstretched filament, and this unstretched filament was stretched 1.3 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 10 dtex.

(Sample 4 , reference example )
A split type composite fiber having a fiber cross section having a split number of 16 as shown in FIG. 2 and comprising a first component and a second component was produced. As a first component, the glass transition point is about 145 ° C., the softening point is 240 ° C., the measurement temperature is 300 ° C. according to JIS-K-7210, and the melt flow rate is 70 g / 10 min at a measurement load of 11.76 N (1.2 kgf). A polycarbonate (trade name: NOVAREX 7020A, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was prepared. As the second component, the melting point is 165 ° C., the measurement temperature is 230 ° C. according to JIS-K-7210, the melt flow rate is 24 g / 10 min at a measurement load of 21.18 N (2.16 kgf), and the density is 0.90 g / cm 3. A certain polypropylene (trade name: SA03A, manufactured by Nippon Polypro Co., Ltd.) was prepared. For these two components, a split type composite nozzle having a split number of 16 is used, the composite ratio (volume ratio) of the first component / second component is 5/5, the spinning temperature of the first component is 275 ° C., The second component is melted at a spinning temperature of 275 ° C., spun from a nozzle outlet into a 40 ° C. hot air blowing atmosphere (wind speed: 2 m / min), taken up at a speed of 750 m / min, and unstretched with a fineness of 11 dtex A filament was obtained. During spinning, no yarn breakage was observed, and spinning was successful. Next, the unstretched filament was stretched 1.4 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 7.8 dtex.

(Sample 5 , reference example )
As a second component, the melting point is 135 ° C., the measurement temperature is 190 ° C. as defined in JIS-K-6922-2, the measurement flow is 21.18 N (2.16 kgf), and the melt flow rate is 7 g /
A split type composite fiber was obtained in the same manner as Sample 4 except that polyethylene (trade name: HF560, manufactured by Nippon Polyethylene Co., Ltd.) was used for 10 min. The obtained fiber was an unstretched filament of 11 dtex. The unstretched filament was stretched 1.4 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 7.8 dtex.

(Sample 6 , Reference example )
A split-type composite fiber was obtained in the same manner as Sample 4 except that a split-type composite nozzle with a split number of 8 was used. The obtained fiber was a 9 dtex unstretched filament, and this unstretched filament was stretched 1.4 times in hot water at 90 ° C. to obtain a stretched filament having a fineness of 7 dtex.

(Sample 7 , Reference example )
A polycarbonate single fiber was produced in the same manner as Sample 1 except that spinning was performed in a 20 ° C. cold air blowing atmosphere (wind speed: 2 m / min). The unstretched filament formed a molten polymer lump, had many yarn breaks, and could not be spun.

Sample 2-3 was excellent in spinnability and had almost no fused or broken fiber, and a fine fiber could be obtained.

  If the method for producing polycarbonate fiber of the present invention is used, fine fibers containing a polycarbonate component can be spun well. Moreover, since this fiber is excellent in the heat resistance, impact resistance, and mechanical strength which are the characteristics of a polycarbonate fiber, for example, if it is a nonwoven fabric, it can be used suitably for a heat resistant filter.

FIG. 1 is a cross-sectional view of a composite fiber in one embodiment of the present invention. FIG. 2 is a cross-sectional view of a composite fiber in a reference example of the present invention.

1 Polycarbonate component 2 Other components other than polycarbonate

Claims (4)

A method for producing a core-sheath type composite fiber containing polycarbonate,
The heated and melted polycarbonate and thermoplastic polymer are spun from a nozzle outlet into a gas atmosphere having an atmospheric temperature of 35 ° C. or higher and lower than the glass transition point of the polycarbonate,
A core sheath containing polycarbonate , characterized in that an unstretched filament comprising a core-sheath type composite fiber having a component containing 50% by mass or more of polycarbonate as a core component and a component containing 50% by mass or more of a thermoplastic polymer as a sheath component is obtained. A method for producing a mold composite fiber. The method for producing a core-sheath type composite fiber containing polycarbonate according to claim 1, wherein the gas atmosphere is a warm air atmosphere and the wind speed is in a range of 1 to 3 m / min. The method for producing a core-sheath type composite fiber containing polycarbonate according to claim 1 or 2 , wherein the fineness of the single fiber of the core-sheath type composite fiber containing polycarbonate is in the range of 0.1 dtex to 20 dtex. The manufacturing method of the core-sheath-type composite fiber containing the polycarbonate of Claim 1 which extends | stretches the said unstretched filament which was spun.

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