WO2023074268A1 - High-strength, high-elongation polypropylene fiber and production method thereof - Google Patents

High-strength, high-elongation polypropylene fiber and production method thereof Download PDF

Info

Publication number
WO2023074268A1
WO2023074268A1 PCT/JP2022/036940 JP2022036940W WO2023074268A1 WO 2023074268 A1 WO2023074268 A1 WO 2023074268A1 JP 2022036940 W JP2022036940 W JP 2022036940W WO 2023074268 A1 WO2023074268 A1 WO 2023074268A1
Authority
WO
WIPO (PCT)
Prior art keywords
polypropylene
temperature
molecular weight
sec
strength
Prior art date
Application number
PCT/JP2022/036940
Other languages
French (fr)
Japanese (ja)
Inventor
緒臣 貝賀
輝之 谷中
Original Assignee
東洋紡株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東洋紡株式会社 filed Critical 東洋紡株式会社
Publication of WO2023074268A1 publication Critical patent/WO2023074268A1/en

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/04—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
    • D01F6/06—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins from polypropylene

Definitions

  • the present invention relates to polypropylene fibers with high strength, high elongation, and high crystallinity, preferably high strength, high elongation, high crystallinity, and excellent thermal stability at the same time. It also relates to polypropylene fibers.
  • Polypropylene fibers are excellent in chemical resistance, heat resistance, light weight, etc., and are widely used in various applications.
  • a method for producing polypropylene fibers for example, the production method of Patent Document 1 is known. It includes a special process of holding and forming fine crystal nuclei, and since it is manually stretched and heat-set by applying tension, it has poor productivity and cannot be applied as an industry. It was difficult.
  • the raw material used has a relatively low weight average molecular weight, a low stretching temperature, and a relatively low heat setting temperature of less than 150 ° C., it is difficult to obtain a high degree of crystallinity, and the strength is excellent. However, it has been difficult to obtain fibers with excellent thermal stability.
  • Patent Literature 1 no consideration is given to elongation.
  • Patent Document 2 a very high molecular weight raw material with an intrinsic viscosity of at least 5 dL/g is fiberized by employing a solution spinning method using a solvent.
  • melt spinning is difficult, and environmental impact due to the solvent used and a recovery step are required, which poses problems from the viewpoint of production cost and environmental impact.
  • the strength of the obtained fiber is as high as 0.832 to 1.376 GPa, but the elongation is as low as 8.3 to 10.4%, and polypropylene fibers having both strength and elongation could not be provided. .
  • melt-spun polypropylene fibers that have high strength, high elongation, high crystallinity, preferably high thermal stability, and can be produced inexpensively without using solvents.
  • the use of high-molecular-weight polymers is generally known as a method for increasing strength. Both elongation and elongation were not achieved.
  • an object of the present invention is to provide a melt-spun polypropylene fiber having high strength, high elongation, high crystallinity, and preferably also high thermal stability, and a method for producing the same.
  • the present inventor melt-spun using polypropylene having a weight-average molecular weight of 6.0 ⁇ 10 5 or more after fiberization, and stretched at a temperature and a deformation speed. By controlling the, it is possible to draw at a high magnification, and it is possible to produce a melt-spun polypropylene fiber having high crystallinity, high strength, high elongation, and high thermal stability. reached.
  • the present invention relates to a polypropylene fiber having high crystallinity, high strength, excellent elongation, and preferably excellent thermal stability.
  • the polypropylene fiber according to . [3] The polypropylene fiber according to [1] or [2] above, which has a dry heat shrinkage rate of 4% or less in a dry heat shrinkage measurement at a treatment temperature of 140° C.
  • the molecular chains of the present invention are highly oriented, it has a high degree of crystallinity, excellent strength and elongation, and also has thermal stability such as resistance to creep during heating and resistance to heat shrinkage. Excellent polypropylene fibers are obtained.
  • Polypropylene fiber The polypropylene fiber of the present invention has a breaking strength of 12.5 cN/dtex or more, a breaking elongation of 15% or more, a weight average molecular weight of 6.0 ⁇ 10 5 or more, and a crystallinity of 64% or more. characterized by
  • the weight average molecular weight (Mw) of the polypropylene fiber in the present invention is 6.0 ⁇ 10 5 or more.
  • the weight average molecular weight is preferably in the range of 6.0 ⁇ 10 5 to 9.0 ⁇ 10 6 , more preferably in the range of 7.0 ⁇ 10 5 to 4.0 ⁇ 10 6 . Most preferably, it ranges from 0.0 ⁇ 10 5 to 3.0 ⁇ 10 6 .
  • the number average molecular weight (Mn) of the polypropylene fiber in the present invention is preferably in the range of 1.0 ⁇ 10 4 to 5.0 ⁇ 10 5 , more preferably 2.0 ⁇ 10 4 to 4.0 ⁇ 10 5 . and most preferably 3.0 ⁇ 10 4 to 3.0 ⁇ 10 5 .
  • the weight-average molecular weight and number-average molecular weight are below this range, the number of molecular chain ends contained in the fiber increases, making it difficult to increase the strength and achieve high-temperature stretching.
  • the weight average molecular weight and number average molecular weight are above this range, the entanglement of the molecular chains increases, making it difficult to stretch and the molecular chains cannot be highly oriented, making it difficult to increase the strength.
  • the weight-average molecular weight and number-average molecular weight of polypropylene fibers are the molecular weight values after fiberization, unless otherwise specified.
  • a weight average molecular weight and a number average molecular weight can be determined by the GPC method.
  • the breaking strength of the polypropylene fiber in the present invention is 12.5 cN/dtex or more, preferably 14 cN/dtex or more, more preferably 15 cN/dtex or more.
  • the upper limit is not particularly limited, it is preferably 25 cN/dtex or less from the viewpoint of stretchability.
  • the breaking elongation of the polypropylene fiber in the present invention is 15% or more, preferably 18% or more, and more preferably 20% or more.
  • the upper limit is not particularly limited, the elongation at break is preferably 35% or less from the viewpoint of handling.
  • the polypropylene fiber of the present invention has a breaking strength of 12.5 cN/dtex or more and a breaking elongation of 15% or more.
  • the crystallinity of the polypropylene fiber in the present invention is 64% or more, preferably 66% or more, and more preferably 68% or more. Although the upper limit is not particularly limited, 95% or less is preferable. It is presumed that the increase in crystallinity leads to improved stability of the fiber structure and a reduction in defects, resulting in improved elongation as well as strength.
  • the creep rate of the polypropylene fiber in the present invention is preferably 1.0 ⁇ 10 ⁇ 6 sec ⁇ 1 or less at a measurement temperature of 70° C. and a load corresponding to 20% of the breaking strength, and 7.0 ⁇ 10 ⁇ 7 sec ⁇ 1 or less is more preferable, and 5.0 ⁇ 10 ⁇ 7 sec ⁇ 1 or less is even more preferable.
  • the lower limit is not particularly limited, it is preferably 1.0 ⁇ 10 ⁇ 9 sec ⁇ 1 or more.
  • the dry heat shrinkage rate of the polypropylene fiber in the present invention is preferably 4% or less, more preferably 3% or less, in dry heat shrinkage measurement at a treatment temperature of 140°C and a treatment time of 30 minutes.
  • the lower limit is not particularly limited, it is preferably 0.5% or more.
  • the elastic modulus of the polypropylene fiber in the present invention is preferably 130 cN/dtex or more, more preferably 140 cN/dtex or more, and 150 cN/dtex or more, from the viewpoint of achieving a high degree of molecular orientation in the fiber axis direction. is more preferable.
  • the upper limit is not particularly limited, it is preferably 200 cN/dtex or less from the viewpoint of not realizing excessive molecular orientation in the fiber axis direction.
  • the method for producing the polypropylene fiber of the present invention is not particularly limited, it is preferably produced by the following production method.
  • the method for producing polypropylene fiber according to the present invention comprises: (1) a step of melt spinning polypropylene having a weight average molecular weight of 6.0 ⁇ 10 5 or more after fiberization (melt spinning step); (2) a step of cooling the resulting melt-spun fibers to a temperature range from the glass transition temperature of the polypropylene used to the glass transition temperature +50°C (cooling step); (3) a step of drawing the cooled fiber at a drawing temperature of 150° C. or higher and 180° C. or lower at a deformation rate of 0.001 sec ⁇ 1 or more and less than 0.1 sec ⁇ 1 (drawing step); including.
  • melt spinning step melt spinning polypropylene having a weight average molecular weight of 6.0 ⁇ 10 5 or more after fiberization
  • cooling step cooling the resulting melt-spun fibers to a temperature range from the glass transition temperature of the polypropylene used to the glass transition temperature +50°C
  • drawing step a step of drawing the cooled fiber at a drawing temperature of 150° C.
  • ⁇ Raw material composition> In the method for producing a polypropylene fiber of the present invention, a raw material composition containing polypropylene is melt-spun, cooled, and drawn to form a polypropylene fiber.
  • the polypropylene in the raw material composition includes isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene. Moreover, it may be in a single form from among these, or in a mixed form of two or more thereof. More specifically, the polypropylene in the raw material composition preferably has a pentad (mmmm) fraction, which is an index of stereoregularity, of 0.8 or more (80% or more), and preferably 0.9 or more (90% or more). % or more), more preferably 0.95 or more (95% or more), and most preferably 0.97 or more (97% or more). The higher the pentad fraction, the higher the stereoregularity and the fewer defects when made into a fiber, which is preferable because it increases the strength.
  • mmmm pentad
  • the polypropylene in the raw material composition may be a homopolymer consisting only of propylene units, may be a copolymer with other monomers, or may be a homopolymer and/or copolymer of two or more may be a mixture of Copolymers can include block copolymers and random copolymers.
  • Monomers other than propylene that form the copolymer are not particularly limited, but include, for example, ethylene and 1-butene. In the present invention, a homopolymer consisting only of propylene units is preferred.
  • the weight average molecular weight (Mw) of polypropylene in the raw material composition is adjusted so that the weight average molecular weight after fiberization is 6.0 ⁇ 10 5 or more.
  • the weight average molecular weight of polypropylene as a raw material is not particularly limited, but is preferably 6.0 ⁇ 10 5 or more, more preferably 7.0 ⁇ 10 5 or more, and more preferably 8.0 ⁇ 10 It is more preferably 5 or more, and most preferably 8.5 ⁇ 10 5 or more.
  • the upper limit of the weight average molecular weight of polypropylene as a raw material is not particularly limited, but it is preferably 1.2 ⁇ 10 6 or less from the viewpoint of not impairing the melt-molding process.
  • melt flow rate can be mentioned as an indicator of molecular weight.
  • MFR test method values measured at a temperature of 230°C and a load of 2.16 kgf, which are general conditions applied to polypropylene resin in accordance with JIS K7210, are used.
  • the MFR of polypropylene as a raw material is preferably 2.4 g/10 min or less, more preferably 2.0 g/10 min or less, still more preferably 1.5 g/10 min or less, and most preferably 1.0 g/10 min or less.
  • the lower limit of MFR is not particularly limited, it is preferably 0.2 g/10 min or more.
  • the raw material composition used in the present invention contains polypropylene, and the content of polypropylene in the raw material composition is not particularly limited, but from the viewpoint of realizing a high degree of crystallinity after fiberization, 95% by mass or more, more preferably 98% by mass or more, even more preferably 99% by mass or more, and particularly preferably substantially only polypropylene (100%).
  • additives used in this field can be added to the raw material composition used in the present invention as long as the effects of the present invention are not impaired. Specifically, 5% by mass of the raw material composition or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.
  • Additives include neutralizing agents, antioxidants, heat stabilizers, weathering agents, lubricants, UV absorbers, antistatic agents, antiblocking agents, antifogging agents, antifogging agents, dispersants, flame retardants, Additives such as antibacterial agents, fluorescent whitening agents, cross-linking agents and cross-linking aids, coloring agents such as dyes and pigments, and the like, among which antioxidants are preferred.
  • ⁇ Melt spinning process> In the method for producing a polypropylene fiber according to the present invention, first, a raw material composition containing polypropylene is melted, the melted product is extruded from a spinning nozzle having a predetermined hole diameter, and is wound by a roller set at a predetermined spinning speed to obtain an unspun fiber. It is preferable to include the step of obtaining a drawn yarn.
  • melt-extrusion of polypropylene a melt-extrusion technique for plastic fibers that is commonly used in the relevant technical field may be used.
  • Means for melt extrusion are not limited, but for example, an extruder that heats and melts a raw material plastic and then presses and extrudes the melt can be used.
  • the spinning temperature of polypropylene is preferably at least the melting point of the polypropylene used (melting point +50° C. or higher), that is, it is preferably at least 50° C. higher than the melting point temperature (melting point +70° C. to melting point +150° C.), That is, it is more preferable to be in the range of 70° C. higher than the melting point to 150° C. higher than the melting point.
  • melt flow it is necessary to suppress the decrease in molecular weight as much as possible during melt flow. From this point of view, if the temperature of the extruder is too high, the polypropylene will deteriorate and the molecular weight will decrease, which is not preferable. On the other hand, if the temperature is too low, the fluidity is lowered, which may cause damage to the apparatus and difficulty in molding due to melt fracture, which is not preferable.
  • the melting point of polypropylene is 150 to 180°C.
  • a method for suppressing the decrease in molecular weight during melt flow it is also preferable to adopt a method such as shortening the melt residence time or adding an antioxidant.
  • the upper limit of the single-hole discharge rate of the spinning nozzle is preferably 1.0 g/min or less, more preferably 0.5 g/min or less. If the single-hole discharge rate is higher than this range, melt fracture or the like may occur, resulting in unstable spinning.
  • the lower limit of the single-hole discharge rate of the spinning nozzle is not particularly limited, but from the viewpoint of productivity, it is preferably 0.05 g/min or more, more preferably 0.1 g/min or more.
  • the spinning speed is preferably 50-700 m/min, more preferably 100-500 m/min. By winding in this speed range, it is possible to control the degree of orientation, crystal structure, etc. in the undrawn yarn, and as a result, the strength of the obtained fiber is improved, which is preferable.
  • the production method of the present invention includes the step of cooling the obtained melt-spun fibers (undrawn fibers) to a temperature range of the glass transition temperature (Tg) of the polypropylene to be used to the glass transition temperature + 50 ° C. .
  • the undrawn yarn is rapidly cooled from the heating temperature in the melt extrusion means to a predetermined temperature A (the glass transition temperature (Tg) of polypropylene to the glass transition temperature + 50 ° C.), and is spun at this temperature A while being taken up.
  • the temperature A is the range of the glass transition temperature (Tg) to (Tg + 50 ° C.) of the polypropylene used, that is, the temperature range from the Tg temperature to 50 ° C. above Tg, and (Tg) to (Tg + 25 ° C.).
  • a temperature in the range is more preferable, and a temperature in the range of (Tg) to (Tg+10° C.) is even more preferable.
  • the Tg of polypropylene is -20°C to 5°C. Cooling can be performed using forced cooling means such as air cooling or refrigerants (eg, water, methanol, ethanol, mixed solvents thereof), or a combination of air cooling and refrigerants.
  • forced cooling means such as air cooling or refrigerants (eg, water, methanol, ethanol, mixed solvents thereof), or a combination of air cooling and refrigerants.
  • drawing process After cooling the undrawn yarn obtained by the melt spinning process, it is drawn by the drawing process to obtain the intended polypropylene fiber.
  • drawing of the undrawn yarn can be carried out using a drawing means commonly used in the technical field.
  • the fiber can be drawn continuously by a speed difference between the delivery roller and the take-up roller.
  • the draw ratio is defined by the speed difference between the delivery roller and the take-up roller.
  • the unstretched yarn pulled out from the delivery roller is heated to a predetermined temperature in an oven of a predetermined length and stretched. Further, the stretching may be performed in one stage or in multiple stages.
  • the draw ratio is preferably 2 times or more, more preferably 5 times or more.
  • the temperature for drawing the undrawn yarn is 150° C. or higher and 180° C. or lower, preferably 150° C. or higher and 175° C. or lower, more preferably 155° C. or higher and 173° C. or lower, and most preferably 160° C. or higher and 173° C. or lower. .
  • the melting point of the polypropylene fiber is increased, and stable drawing near the melting point becomes possible, and drawing at a relatively high temperature becomes possible. This makes it possible to obtain fibers with relatively high crystallinity and relatively low thermal shrinkage. If the drawing temperature is lower than 150° C., the crystallinity of the resulting fiber will be low, making it difficult to obtain a polypropylene fiber with high strength and high elongation.
  • the drawing temperature is in the temperature range from (glass transition temperature (Tg) + 150°C) to (Tg + 200°C), that is, the temperature range from 150°C above the Tg of the undrawn yarn to 200°C above the Tg. is preferred.
  • the undrawn yarn according to the present invention has a Tg of 0 to 20°C.
  • the delivery roller speed, take-up roller speed, and oven length are adjusted so that the deformation speed shown in the following formula is 0.001 sec ⁇ 1 or more and less than 0.1 sec ⁇ 1 , and 0.001 sec ⁇ 1 or more and 0.001 sec ⁇ 1 or more and less than 0.1 sec ⁇ 1 . 05 sec ⁇ 1 or less is preferable. If the deformation rate is higher than this range, the deformation rate of the high-molecular-weight polymer cannot catch up with the deformation rate of the drawing, resulting in a decrease in drawability. In addition, stretching at a deformation rate lower than this range lowers productivity. By adjusting the deformation speed within this range, uniform drawing becomes possible, so that the draw ratio is improved and the strength of the resulting fiber is improved.
  • Deformation speed (sec -1 ) [winding roller speed (m/sec) - delivery roller speed (m/sec)]/oven length (m)
  • Drawing is one of the challenges in obtaining high-strength fibers using high-molecular-weight polymers.
  • the use of a high-molecular-weight polymer tends to hinder stretching and make it difficult to stretch.
  • the reason for this is thought to be that the relaxation time becomes longer when the polymer has a higher molecular weight. Therefore, in the present invention, a drawing temperature of 150 to 180° C., which is a relatively high temperature near the melting point, is adopted, and the drawing is performed at a low deformation rate corresponding to the relaxation time of the polymer with a high molecular weight.
  • the method for producing polypropylene fibers of the present invention includes a melt spinning step, a cooling step, and a drawing step, but may include other steps within a range that does not impair the effects of the present invention.
  • the production method of the present invention employs a relatively high stretching temperature (150 to 180° C.), it does not require heat treatment after stretching, and does not include a heat treatment step after stretching.
  • the breaking strength, breaking elongation, weight average molecular weight, creep rate, dry heat shrinkage, and crystallinity of the polypropylene fiber obtained by the above production method are within the above ranges.
  • the molecular weight reduction from the raw material polypropylene resin to the finally obtained fiber is suppressed, and the molecular weight reduction rate ((weight average molecular weight of the raw material polypropylene resin - final The weight average molecular weight of the obtained fiber) / weight average molecular weight of the raw material polypropylene resin ⁇ 100) is preferably 35% or less, more preferably 25% or less, and 20% or less. More preferably, it is particularly preferably 15% or less.
  • Weight Average Molecular Weight The weight average molecular weight was measured using a high-temperature GPC analyzer HLC-8321GPC/HT manufactured by Tosoh Corporation as follows. Using o-dichlorobenzene as a solvent, the concentration of polypropylene was adjusted to 0.12% by mass. Further, 0.05% by mass of dibutylhydroxytoluene was added as an antioxidant to prepare a measurement sample. Waters Sytragel HT 3,4,6E was used for the column, and the measurement temperature was set to 140°C. 200 ⁇ L of the measurement sample was injected into the measuring device, and the measurement was performed at a flow rate of 0.3 mL/min. RI (polarity ( ⁇ )) was used as a detector.
  • HLC-8321GPC/HT manufactured by Tosoh Corporation as follows. Using o-dichlorobenzene as a solvent, the concentration of polypropylene was adjusted to 0.12% by mass. Further, 0.05% by mass of dibutylhydroxytolu
  • Fineness A sample was cut into 10 m lengths at five different positions, the mass was measured, and the average value was converted to 10000 m to obtain fineness (dtex).
  • one of the free ends of the sample 1 is fixed at the portion protruding from the metal plate 2 (fixed end 4 of the sample), and the other free end is the portion protruding from the metal plate 2.
  • the initial load was removed and a predetermined load 3 (20% of the breaking strength) was applied.
  • the cover 5 is closed from the upper side for heat retention so that the sample 1 on the metal plate 2 does not touch (the cover 5 and the sample 1 are not in contact), and creep measurement is started.
  • the lid 5 was opened and the measurement was performed.
  • the elongation L i (mm) of the sample at a certain time t is the distance L (t) between the marks attached to the sample 1 at that time t and the distance L 0 (50. 0 cm) and is expressed as follows.
  • ⁇ i (t) (%) (L (t) - L 0 ) x 100/L 0
  • the creep rate ⁇ (sec ⁇ 1 ) is defined as the change in length of the sample per second of time, and the creep rate ⁇ i for each measurement time is expressed as follows.
  • ⁇ i (sec ⁇ 1 ) [( ⁇ i ⁇ i ⁇ 1 )/(t i ⁇ t i ⁇ 1 )]/100
  • the distance between the marks was measured from the start of the measurement until 5 hours later, the creep rate ⁇ i for each measurement time was plotted on a logarithmic scale, and the minimum value was taken as the measured creep rate of the sample. After 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours from the start of measurement, a total of 5 measurements were taken. If there is a minute change of less than 0.5 mm of the measurement range, the measurement is excluded. The average of the values obtained by measuring twice was used for the creep rate.
  • Crystallinity Measured using a differential scanning calorimeter DSC25 manufactured by TA Instruments. The degree of crystallinity was calculated by the following formula as the ratio of crystalline regions in the polymer.
  • the heat of fusion of a complete crystal is the heat of fusion when the degree of crystallinity is 100%, and polypropylene is 209 J/g.
  • Crystallinity (%) (measured heat of fusion/heat of fusion of complete crystal) x 100 Cut the sample to 3 to 5 mm or less, fill and seal about 2 mg in an aluminum pan, and use a similar empty aluminum pan as a reference, under a nitrogen gas atmosphere, from 30 ° C. to 250 ° C. at a rate of 10 ° C./min. The area of the obtained endothermic peak was taken as the measured heat of fusion. The average of the values obtained by measuring twice was used for the degree of crystallinity.
  • Melting point Measurement was performed using a differential scanning calorimeter DSC25 manufactured by TA Instruments. Cut the sample to 3 to 5 mm or less, fill and seal about 2 mg in an aluminum pan, and use a similar empty aluminum pan as a reference, under a nitrogen gas atmosphere, from 30 ° C. to 250 ° C. at a rate of 10 ° C./min. The temperature at the endothermic peak top obtained was taken as the melting point. As the melting point, the average of the values obtained by measuring twice was used.
  • the pentad (mmmm) fraction F (mmmm) is expressed as follows.
  • Example 1 Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 ⁇ 10 5 ), spinning temperature: 295 ° C., single hole discharge rate: 0.26 g / It is melt extruded from a spinneret with a hole diameter of ⁇ 0.4 mm under the conditions of min, and cooled and solidified by blowing cooling air with a quenching temperature of 23° C. at 0.5 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.5 times under the conditions of drawing temperature: 171° C. and deformation speed: 0.02 sec ⁇ 1 to obtain polypropylene fiber 1 . Physical properties are shown in Table 1.
  • Example 2 Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 ⁇ 10 5 ), spinning temperature: 295 ° C., single hole discharge rate: 0.20 g / It is melt extruded from a spinneret with a hole diameter of ⁇ 0.4 mm under the conditions of min, and cooled and solidified by blowing a cooling air with a quenching temperature of 20° C. at 0.5 m/sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 500 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 171° C. and deformation speed: 0.02 sec ⁇ 1 to obtain polypropylene fiber 2 . Physical properties are shown in Table 1.
  • Example 3 Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 ⁇ 10 5 ), spinning temperature: 291 ° C., single hole discharge rate: 0.21 g / It is melt extruded from a spinneret with a hole diameter of ⁇ 0.4 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 20 ° C. at 0.55 m / sec perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 172° C. and deformation rate: 0.01 sec ⁇ 1 to obtain polypropylene fiber 3 . Physical properties are shown in Table 1.
  • Example 4 Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 ⁇ 10 5 ), spinning temperature: 291 ° C., single hole discharge rate: 0.21 g / It is melt extruded from a spinneret with a hole diameter of ⁇ 0.4 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 20 ° C. at 0.6 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 172° C. and deformation speed: 0.04 sec ⁇ 1 to obtain polypropylene fiber 4 . Physical properties are shown in Table 1.
  • Example 5 Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 ⁇ 10 5 ), spinning temperature: 296 ° C., single hole discharge rate: 0.26 g / It is melt extruded from a spinneret with a hole diameter of ⁇ 0.3 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 23 ° C. at 0.6 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.5 times under the conditions of drawing temperature: 151° C. and deformation speed: 0.02 sec ⁇ 1 to obtain polypropylene fiber 5 . Physical properties are shown in Table 1.
  • Example 6 Using a commercially available polypropylene resin (manufactured by Japan Polypropylene Corporation, EA9, MFR: 0.5 g/10 min, weight average molecular weight: 9.2 ⁇ 10 5 ), spinning temperature: 295 ° C., single hole discharge amount: 0.27 g /min, melt extruded from a spinneret with a hole diameter of ⁇ 0.6 mm, and cooled and solidified by blowing a cooling wind with a quenching temperature of 18 ° C. at 0.5 m / sec in the direction perpendicular to the yarn running direction, This was wound up at a spinning speed of 375 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 5.5 times under the conditions of drawing temperature: 172° C. and deformation rate: 0.01 sec ⁇ 1 to obtain polypropylene fiber 6 . Physical properties are shown in Table 1.
  • Example 7 Sumilizer GA-80 (manufactured by Sumitomo Chemical Co., Ltd.) was added to a commercially available polypropylene resin (manufactured by Japan Polypropylene Corporation, EA9, MFR: 0.5 g/10 min, weight average molecular weight: 9.2 ⁇ 10 5 ) as an antioxidant. 0.1% by mass and 0.2% by mass of ADEKA STAB PEP-36 (manufactured by ADEKA Co., Ltd.). : Melt extruded from a spinneret with a hole diameter of ⁇ 0.6 mm under the condition of 0.23 g / min, and cooled and solidified by blowing cooling air with a quench temperature of 22 ° C.
  • Example 1 When the undrawn yarn obtained in Example 1 was drawn under the conditions of a drawing temperature of 171° C. and a deformation rate of 0.20 sec ⁇ 1 , it could only be drawn up to a maximum of 5.0 times.
  • Table 2 shows the physical properties of the polypropylene fiber 8 obtained by drawing 5.0 times.
  • Example 3 The undrawn yarn obtained in Example 4 was drawn 4.5 times under the conditions of drawing temperature: 172° C. and deformation speed: 0.12 sec ⁇ 1 to obtain polypropylene fiber 10 . Physical properties are shown in Table 2.
  • Example 4 The undrawn yarn obtained in Example 5 was drawn 5.0 times under the conditions of drawing temperature: 121° C. and deformation rate: 0.01 sec ⁇ 1 to obtain polypropylene fiber 11 . Physical properties are shown in Table 2.
  • Comparative Example 2 the raw material polypropylene had a low weight average molecular weight, and as a result, the obtained polypropylene fiber had a low weight average molecular weight, low crystallinity, and poor strength. In addition, the thermal stability was not sufficient. In Comparative Example 4, the temperature during drawing was low, and as a result, although the elongation of the obtained polypropylene fiber was excellent, the degree of crystallinity was low and the strength was inferior. In addition, the thermal stability was not sufficient.
  • the present invention makes it possible to produce polypropylene fibers with high strength, high elongation, and high crystallinity.
  • the polypropylene fiber of the present invention is suitable for reinforcing fibers for fiber-reinforced resins, ropes, fishing lines and the like.
  • Creep rate measuring device (with lid open) Creep rate measuring device (cover closed)

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Artificial Filaments (AREA)

Abstract

The purpose of the present invention is to provide melt spun polypropylene fibers that have high strength and high elongation and that have a high crystallization degree, and also to provide melt spun polypropylene fibers that have high strength and high elongation, that have a high degree of crystallization, and that have a high thermal stability represented by creep speed and dry heat shrinkage rate. It was found that by melt spinning using polypropylene with a weight average molecular weight after fiberization of 6.0×105 as the raw material and by controlling the fiber temperature and the deformation speed during rolling, it is possible to produce melt spun polypropylene fibers that can be rolled with the molecule chains highly oriented with high magnification, that have a high degree of crystallization, that have high strength and high elongation, and that have high thermal stability.

Description

高強度高伸度ポリプロピレン繊維及びその製造方法High-strength, high-elongation polypropylene fiber and method for producing the same
　本発明は、高強度、且つ高伸度であり、高結晶化度であるポリプロピレン繊維に関し、好ましくは、高強度、且つ高伸度であり、高結晶化度であり、同時に熱安定性に優れた、ポリプロピレン繊維に関する。 The present invention relates to polypropylene fibers with high strength, high elongation, and high crystallinity, preferably high strength, high elongation, high crystallinity, and excellent thermal stability at the same time. It also relates to polypropylene fibers.
　ポリプロピレン繊維は、耐薬品性、耐熱性、軽量性等に優れるものであり、種々の用途に広く用いられている。ポリプロピレン繊維の製造方法としては、例えば、特許文献１の製造方法が知られているが、特許文献１においては、重量平均分子量が５．１×１０５と比較的低い分子量のポリマーを用い、低温保持して微細な結晶核を形成する特殊工程を含むものであり、且つ手回し延伸を実施して、張力を付与して熱セットを実施しているため、生産性が乏しく産業として適用させることが困難であった。さらに、用いている原料の重量平均分子量が比較的低く、延伸温度も低く、且つ熱セット温度が１５０℃未満と比較的低いため、高結晶化度を得ることが難しく、強度は優れているものの、熱安定性に優れた繊維を得ることは困難であった。また、特許文献１においては、伸度については何ら検討がなされていないものであった。 Polypropylene fibers are excellent in chemical resistance, heat resistance, light weight, etc., and are widely used in various applications. As a method for producing polypropylene fibers, for example, the production method of Patent Document 1 is known. It includes a special process of holding and forming fine crystal nuclei, and since it is manually stretched and heat-set by applying tension, it has poor productivity and cannot be applied as an industry. It was difficult. Furthermore, since the raw material used has a relatively low weight average molecular weight, a low stretching temperature, and a relatively low heat setting temperature of less than 150 ° C., it is difficult to obtain a high degree of crystallinity, and the strength is excellent. However, it has been difficult to obtain fibers with excellent thermal stability. Moreover, in Patent Literature 1, no consideration is given to elongation.
　特許文献２では、極限粘度が少なくとも５ｄＬ／ｇ以上と極めて高い分子量原料を、溶剤を用いる溶液紡糸方法を採用し繊維化したものである。この分子量範囲においては、溶融紡糸は困難であり、使用溶媒による環境負荷や回収工程が必要となることから、生産コスト並びに環境負荷の観点から問題があった。得られた繊維の強度は０．８３２～１．３７６ＧＰａと高強度であるが、伸度が８．３～１０．４％と低く、強度と伸度が両立したポリプロピレン繊維が提供できていなかった。 In Patent Document 2, a very high molecular weight raw material with an intrinsic viscosity of at least 5 dL/g is fiberized by employing a solution spinning method using a solvent. In this molecular weight range, melt spinning is difficult, and environmental impact due to the solvent used and a recovery step are required, which poses problems from the viewpoint of production cost and environmental impact. The strength of the obtained fiber is as high as 0.832 to 1.376 GPa, but the elongation is as low as 8.3 to 10.4%, and polypropylene fibers having both strength and elongation could not be provided. .
特開２０１３－２４９５５４号公報JP 2013-249554 A 特開平６－４１８１４号公報JP-A-6-41814
本発明が解決しようとする課題Problems to be solved by the present invention
　高強度及び高伸度であり、結晶化度が高く、好ましくは高い熱安定性を有し、溶剤を用いず安価に製造可能な溶融紡糸ポリプロピレン繊維が工業的に望まれている。高強度化の方法として、一般的に高分子量ポリマーの使用が知られているが、溶液紡糸方法等で無理やり延伸倍率を上げ高強度化した場合、伸度が低下し、結果として高強度、高伸度の両立には至っていなかった。 There is an industrial demand for melt-spun polypropylene fibers that have high strength, high elongation, high crystallinity, preferably high thermal stability, and can be produced inexpensively without using solvents. The use of high-molecular-weight polymers is generally known as a method for increasing strength. Both elongation and elongation were not achieved.
　またさらに、高い延伸倍率を付与すると、クリープ速度や乾熱収縮率に代表される熱安定性が低下し、高強度と高い熱安定性を両立させることも従来困難であった。 Furthermore, when a high draw ratio is applied, the thermal stability represented by creep speed and dry heat shrinkage decreases, and it was conventionally difficult to achieve both high strength and high thermal stability.
　そこで、本発明の目的は、高強度、高伸度、高結晶化度であり、好ましくは高い熱安定性をも有する溶融紡糸ポリプロピレン繊維、及びその製造方法を提供することである。 Accordingly, an object of the present invention is to provide a melt-spun polypropylene fiber having high strength, high elongation, high crystallinity, and preferably also high thermal stability, and a method for producing the same.
　本発明者は、前記課題を解決すべく鋭意検討を行った結果、繊維化後の重量平均分子量が６．０×１０５以上となるポリプロピレンを用いて溶融紡糸し、延伸時の温度、変形速度を制御することにより、高倍率での延伸が可能となり、高結晶化度であり、高強度、高伸度であり、かつ高い熱安定性を有する溶融紡糸ポリプロピレン繊維を製造できることを見出し、本発明に至った。 As a result of intensive studies to solve the above problems, the present inventor melt-spun using polypropylene having a weight-average molecular weight of 6.0 × 10 5 or more after fiberization, and stretched at a temperature and a deformation speed. By controlling the, it is possible to draw at a high magnification, and it is possible to produce a melt-spun polypropylene fiber having high crystallinity, high strength, high elongation, and high thermal stability. reached.
　すなわち、本発明は、高結晶化度であり、高強度、高伸度に優れ、好ましくは優れた熱安定性を有するポリプロピレン繊維に関する。 That is, the present invention relates to a polypropylene fiber having high crystallinity, high strength, excellent elongation, and preferably excellent thermal stability.
［１］破断強度が１２．５ｃＮ／ｄｔｅｘ以上、破断伸度が１５％以上、重量平均分子量が６．０×１０５以上、且つ結晶化度が６４％以上であることを特徴とするポリプロピレン繊維。
［２］測定温度が７０℃、測定荷重が破断強度の２０％に相当する荷重におけるクリープ測定において、クリープ速度が１．０×１０－６ｓｅｃ－１以下であることを特徴とする前記［１］に記載のポリプロピレン繊維。
［３］処理温度が１４０℃、処理時間が３０分における乾熱収縮測定において、乾熱収縮率が４％以下であることを特徴とする前記［１］又は［２］に記載のポリプロピレン繊維。
［４］弾性率が、１３０ｃＮ／ｄｔｅｘ以上であることを特徴とする前記［１］～［３］のいずれかに記載のポリプロピレン繊維。
［５］繊維化後の重量平均分子量が６．０×１０５以上であるポリプロピレンを溶融紡糸した後、
　使用されるポリプロピレンのガラス転移温度～前記ガラス転移温度温度＋５０℃の温度範囲に冷却した後、
　１５０℃以上１８０℃以下の延伸温度において、変形速度が０．００１ｓｅｃ－１以上０．１ｓｅｃ－１未満で延伸したことを特徴とする、前記［１］～［４］のいずれかに記載したポリプロピレン繊維の製造方法。 [1] A polypropylene fiber having a breaking strength of 12.5 cN/dtex or more, a breaking elongation of 15% or more, a weight average molecular weight of 6.0×10 5 or more, and a crystallinity of 64% or more. .
[2] The above [1], wherein the creep rate is 1.0×10 −6 sec −1 or less in creep measurement at a measurement temperature of 70° C. and a load corresponding to 20% of the breaking strength. ] The polypropylene fiber according to .
[3] The polypropylene fiber according to [1] or [2] above, which has a dry heat shrinkage rate of 4% or less in a dry heat shrinkage measurement at a treatment temperature of 140° C. for a treatment time of 30 minutes.
[4] The polypropylene fiber according to any one of [1] to [3], which has an elastic modulus of 130 cN/dtex or more.
[5] After melt spinning a polypropylene having a weight average molecular weight of 6.0×10 5 or more after fiberization,
After cooling to a temperature range from the glass transition temperature of the polypropylene used to the glass transition temperature + 50 ° C.,
The polypropylene according to any one of [1] to [4] above, which is stretched at a deformation rate of 0.001 sec −1 or more and less than 0.1 sec −1 at a stretching temperature of 150° C. or more and 180° C. or less. A method of manufacturing fibers.
　本発明は、分子鎖が高度に配向していることから、高結晶化度であり、強度、伸度に優れており、また加熱時にクリープしにくく、熱収縮しにくい等の熱安定性にも優れたポリプロピレン繊維が得られる。 Since the molecular chains of the present invention are highly oriented, it has a high degree of crystallinity, excellent strength and elongation, and also has thermal stability such as resistance to creep during heating and resistance to heat shrinkage. Excellent polypropylene fibers are obtained.
　以下、本発明の実施形態について説明するが、本発明はこれらの実施形態のみに限定されるものではない。 Embodiments of the present invention will be described below, but the present invention is not limited only to these embodiments.
１．ポリプロピレン繊維
　本発明のポリプロピレン繊維は、破断強度が１２．５ｃＮ／ｄｔｅｘ以上、破断伸度が１５％以上、重量平均分子量が６．０×１０５以上、且つ結晶化度が６４％以上であることを特徴とする。 1. Polypropylene fiber The polypropylene fiber of the present invention has a breaking strength of 12.5 cN/dtex or more, a breaking elongation of 15% or more, a weight average molecular weight of 6.0 × 10 5 or more, and a crystallinity of 64% or more. characterized by
　本発明におけるポリプロピレン繊維の重量平均分子量（Ｍｗ）は、６．０×１０５以上である。前記重量平均分子量は、６．０×１０５～９．０×１０６の範囲であることが好ましく、７．０×１０５～４．０×１０６の範囲であることがさらに好ましく、８．０×１０５～３．０×１０６の範囲であることが最も好ましい。また、本発明におけるポリプロピレン繊維の数平均分子量（Ｍｎ）は、１．０×１０４～５．０×１０５の範囲であることが好ましく、２．０×１０４～４．０×１０５の範囲であることが好ましく、３．０×１０４～３．０×１０５の範囲であることが最も好ましい。この範囲以下の重量平均分子量、数平均分子量では、繊維に含まれる分子鎖末端数が多くなるため、高強度化が困難となり、且つ高温での延伸が実現困難となる。また、この範囲以上の重量平均分子量、数平均分子量では、分子鎖の絡み合いが多くなることで、延伸しにくくなり、分子鎖を高度に配向できなくなるため、高強度化が困難となる。なお本発明における、ポリプロピレン繊維の重量平均分子量、数平均分子量は、特に記載が無い限り繊維化後の分子量値である。重量平均分子量、数平均分子量はＧＰＣ法によって決定することができる。 The weight average molecular weight (Mw) of the polypropylene fiber in the present invention is 6.0×10 5 or more. The weight average molecular weight is preferably in the range of 6.0×10 5 to 9.0×10 6 , more preferably in the range of 7.0×10 5 to 4.0×10 6 . Most preferably, it ranges from 0.0×10 5 to 3.0×10 6 . Also, the number average molecular weight (Mn) of the polypropylene fiber in the present invention is preferably in the range of 1.0×10 4 to 5.0×10 5 , more preferably 2.0×10 4 to 4.0×10 5 . and most preferably 3.0×10 4 to 3.0×10 5 . If the weight-average molecular weight and number-average molecular weight are below this range, the number of molecular chain ends contained in the fiber increases, making it difficult to increase the strength and achieve high-temperature stretching. In addition, when the weight average molecular weight and number average molecular weight are above this range, the entanglement of the molecular chains increases, making it difficult to stretch and the molecular chains cannot be highly oriented, making it difficult to increase the strength. In the present invention, the weight-average molecular weight and number-average molecular weight of polypropylene fibers are the molecular weight values after fiberization, unless otherwise specified. A weight average molecular weight and a number average molecular weight can be determined by the GPC method.
　本発明におけるポリプロピレン繊維の破断強度は、１２．５ｃＮ／ｄｔｅｘ以上であり、好ましくは１４ｃＮ／ｄｔｅｘ以上であり、より好ましくは１５ｃＮ／ｄｔｅｘ以上である。上限は特に限定されないが、延伸加工性の観点から、２５ｃＮ／ｄｔｅｘ以下であることが好ましい。 The breaking strength of the polypropylene fiber in the present invention is 12.5 cN/dtex or more, preferably 14 cN/dtex or more, more preferably 15 cN/dtex or more. Although the upper limit is not particularly limited, it is preferably 25 cN/dtex or less from the viewpoint of stretchability.
　本発明におけるポリプロピレン繊維の破断伸度は、１５％以上であり、好ましくは１８％以上であり、より好ましくは２０％以上である。上限は特に限定されないが、ハンドリングの観点から破断伸度は３５％以下であることが好ましい。 The breaking elongation of the polypropylene fiber in the present invention is 15% or more, preferably 18% or more, and more preferably 20% or more. Although the upper limit is not particularly limited, the elongation at break is preferably 35% or less from the viewpoint of handling.
　本発明のポリプロピレン繊維は、破断強度が１２．５ｃＮ／ｄｔｅｘ以上、且つ破断伸度が１５％以上であり、破断強度と破断伸度を両立でき、幅広い用途に適用することが可能である。 The polypropylene fiber of the present invention has a breaking strength of 12.5 cN/dtex or more and a breaking elongation of 15% or more.
　本発明におけるポリプロピレン繊維の結晶化度は、６４％以上であり、６６％以上であることが好ましく、６８％以上であることがより好ましい。上限は特に限定されないが、９５％以下が好ましい。結晶化度が高くなることによって繊維構造の安定性向上ならびに欠陥の減少につながり、強度のみならず伸度も向上したものと推察される。 The crystallinity of the polypropylene fiber in the present invention is 64% or more, preferably 66% or more, and more preferably 68% or more. Although the upper limit is not particularly limited, 95% or less is preferable. It is presumed that the increase in crystallinity leads to improved stability of the fiber structure and a reduction in defects, resulting in improved elongation as well as strength.
　本発明におけるポリプロピレン繊維のクリープ速度は、測定温度が７０℃、測定荷重が破断強度の２０％に相当する荷重において、１．０×１０－６ｓｅｃ－１以下であることが好ましく、７．０×１０－７ｓｅｃ－１以下であることがより好ましく、５．０×１０－７ｓｅｃ－１以下であることがさらに好ましい。下限は特に限定されないが、１．０×１０－９ｓｅｃ－１以上が好ましい。 The creep rate of the polypropylene fiber in the present invention is preferably 1.0×10 −6 sec −1 or less at a measurement temperature of 70° C. and a load corresponding to 20% of the breaking strength, and 7.0 ×10 −7 sec −1 or less is more preferable, and 5.0×10 −7 sec −1 or less is even more preferable. Although the lower limit is not particularly limited, it is preferably 1.0×10 −9 sec −1 or more.
　本発明におけるポリプロピレン繊維の乾熱収縮率は、処理温度が１４０℃、処理時間が３０分における乾熱収縮測定において、４％以下であることが好ましく、３％以下であることがより好ましい。下限は特に限定されないが、０．５％以上が好ましい。 The dry heat shrinkage rate of the polypropylene fiber in the present invention is preferably 4% or less, more preferably 3% or less, in dry heat shrinkage measurement at a treatment temperature of 140°C and a treatment time of 30 minutes. Although the lower limit is not particularly limited, it is preferably 0.5% or more.
　本発明におけるポリプロピレン繊維の弾性率は、繊維軸方向への高度な分子配向を実現させる観点から、１３０ｃＮ／ｄｔｅｘ以上であることが好ましく、１４０ｃＮ／ｄｔｅｘ以上であることがより好ましく、１５０ｃＮ／ｄｔｅｘ以上であることがさらに好ましい。上限は特に限定されないが、繊維軸方向への過剰な分子配向を実現させない観点から、２００ｃＮ／ｄｔｅｘ以下であることが好ましい。 The elastic modulus of the polypropylene fiber in the present invention is preferably 130 cN/dtex or more, more preferably 140 cN/dtex or more, and 150 cN/dtex or more, from the viewpoint of achieving a high degree of molecular orientation in the fiber axis direction. is more preferable. Although the upper limit is not particularly limited, it is preferably 200 cN/dtex or less from the viewpoint of not realizing excessive molecular orientation in the fiber axis direction.
　本発明のポリプロピレン繊維の製造方法は、特に限定されないが、以下の製造方法によって製造されることが好ましい。 Although the method for producing the polypropylene fiber of the present invention is not particularly limited, it is preferably produced by the following production method.
２．ポリプロピレン繊維の製造方法
　本発明に係るポリプロピレン繊維の製造方法は、
（１）繊維化後の重量平均分子量が６．０×１０５以上であるポリプロピレンを溶融紡糸する工程（溶融紡糸工程）、
（２）得られた溶融紡糸された繊維を、使用されるポリプロピレンのガラス転移温度～前記ガラス転移温度温度＋５０℃の温度範囲に冷却する工程（冷却工程）、
（３）冷却後の繊維を、１５０℃以上１８０℃以下の延伸温度において、変形速度が０．００１ｓｅｃ－１以上０．１ｓｅｃ－１未満で延伸する工程（延伸工程）、
を含む。以下、本発明の製造方法の各工程及び使用する原料ポリプロピレンについて説明する。 2. Method for producing polypropylene fiber The method for producing polypropylene fiber according to the present invention comprises:
(1) a step of melt spinning polypropylene having a weight average molecular weight of 6.0×10 5 or more after fiberization (melt spinning step);
(2) a step of cooling the resulting melt-spun fibers to a temperature range from the glass transition temperature of the polypropylene used to the glass transition temperature +50°C (cooling step);
(3) a step of drawing the cooled fiber at a drawing temperature of 150° C. or higher and 180° C. or lower at a deformation rate of 0.001 sec −1 or more and less than 0.1 sec −1 (drawing step);
including. Hereinafter, each step of the production method of the present invention and raw material polypropylene to be used will be described.
＜原料組成物＞
　本発明のポリプロピレン繊維の製造方法では、ポリプロピレンを含む原料組成物を用いて、溶融紡糸、冷却、延伸して、ポリプロピレン繊維を形成する。 <Raw material composition>
In the method for producing a polypropylene fiber of the present invention, a raw material composition containing polypropylene is melt-spun, cooled, and drawn to form a polypropylene fiber.
　前記原料組成物中のポリプロピレンは、アイソタクチックポリプロピレン、シンジオタクチックポリプロピレン、アタクチックポリプロピレンを含む。また、このうちから単独の形態であってもよく、２種以上の混合形態であってもよい。より具体的には、原料組成物中のポリプロピレンは、立体規則性の指標であるペンタッド（ｍｍｍｍ）分率が、０．８以上（８０％以上）であることが好ましく、０．９以上（９０％以上）であることがより好ましく、０．９５以上（９５％以上）であることがさらに好ましく、０．９７以上（９７％以上）であることが最も好ましい。ペンタッド分率が高いほど、立体規則性が高くなり、繊維にしたときの欠陥が少なるため、高強度化するため好ましい。 The polypropylene in the raw material composition includes isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene. Moreover, it may be in a single form from among these, or in a mixed form of two or more thereof. More specifically, the polypropylene in the raw material composition preferably has a pentad (mmmm) fraction, which is an index of stereoregularity, of 0.8 or more (80% or more), and preferably 0.9 or more (90% or more). % or more), more preferably 0.95 or more (95% or more), and most preferably 0.97 or more (97% or more). The higher the pentad fraction, the higher the stereoregularity and the fewer defects when made into a fiber, which is preferable because it increases the strength.
　前記原料組成物中のポリプロピレンは、プロピレン単位のみからなる単独重合体であってもよく、他のモノマーとの共重合体であってもよく、２種以上の単独重合体及び／又は共重合体の混合物であってもよい。共重合体としては、ブロックコポリマー及びランダムコポリマーを挙げることができる。共重合体を形成するプロピレン以外のモノマーとしては、特に限定されないが、例えば、エチレン及び１－ブテン等を挙げることができる。本発明においては、プロピレン単位のみからなる単独重合体であることが好ましい。 The polypropylene in the raw material composition may be a homopolymer consisting only of propylene units, may be a copolymer with other monomers, or may be a homopolymer and/or copolymer of two or more may be a mixture of Copolymers can include block copolymers and random copolymers. Monomers other than propylene that form the copolymer are not particularly limited, but include, for example, ethylene and 1-butene. In the present invention, a homopolymer consisting only of propylene units is preferred.
　前記原料組成物中のポリプロピレンの重量平均分子量（Ｍｗ）は、繊維化後の重量平均分子量が６．０×１０５以上となるように調整される。具体的に、原料のポリプロピレンの重量平均分子量は、特に限定されないが、６．０×１０５以上であることが好ましく、７．０×１０５以上であることがより好ましく、８．０×１０５以上であることがさらに好ましく、８．５×１０５以上であることが最も好ましい。また、原料のポリプロピレンの重量平均分子量の上限値は特に限定されるものではないが、溶融成型加工を損なわない観点から、１．２×１０６以下であることが好ましい。 The weight average molecular weight (Mw) of polypropylene in the raw material composition is adjusted so that the weight average molecular weight after fiberization is 6.0×10 5 or more. Specifically, the weight average molecular weight of polypropylene as a raw material is not particularly limited, but is preferably 6.0×10 5 or more, more preferably 7.0×10 5 or more, and more preferably 8.0×10 It is more preferably 5 or more, and most preferably 8.5×10 5 or more. The upper limit of the weight average molecular weight of polypropylene as a raw material is not particularly limited, but it is preferably 1.2×10 6 or less from the viewpoint of not impairing the melt-molding process.
　また、分子量を表す指標としてメルトフローレイト（ＭＦＲ）が挙げられる。ＭＦＲ試験法として、ＪＩＳ　Ｋ７２１０でポリプロピレン樹脂に適用される一般的な条件である温度２３０℃、荷重２．１６ｋｇｆにおいて測定された値を用いる。原料のポリプロピレンのＭＦＲとしては、２．４ｇ／１０ｍｉｎ以下が好ましく、２．０ｇ／１０ｍｉｎ以下がより好ましく、１．５ｇ／１０ｍｉｎ以下がさらに好ましく、１．０ｇ／１０ｍｉｎ以下が最も好ましい。また、ＭＦＲの下限値は特に限定されないが、０．２ｇ／１０ｍｉｎ以上であることが好ましい。 In addition, melt flow rate (MFR) can be mentioned as an indicator of molecular weight. As the MFR test method, values measured at a temperature of 230°C and a load of 2.16 kgf, which are general conditions applied to polypropylene resin in accordance with JIS K7210, are used. The MFR of polypropylene as a raw material is preferably 2.4 g/10 min or less, more preferably 2.0 g/10 min or less, still more preferably 1.5 g/10 min or less, and most preferably 1.0 g/10 min or less. Although the lower limit of MFR is not particularly limited, it is preferably 0.2 g/10 min or more.
　また、本発明で使用する原料組成物はポリプロピレンを含むものであり、原料組成物中におけるポリプロピレンの含有量は、特に限定されないが、繊維化後の高結晶化度実現の観点から、９５質量％以上であることが好ましく、９８質量％以上であることがより好ましく、９９質量％以上であることがさらに好ましく、実質ポリプロピレンのみ（１００％）であることが特に好ましい。 In addition, the raw material composition used in the present invention contains polypropylene, and the content of polypropylene in the raw material composition is not particularly limited, but from the viewpoint of realizing a high degree of crystallinity after fiberization, 95% by mass or more, more preferably 98% by mass or more, even more preferably 99% by mass or more, and particularly preferably substantially only polypropylene (100%).
　また、本発明で使用する原料組成物には、本発明の効果を損なわない範囲でこの分野で使用される各種添加剤を添加することができ、具体的には、原料組成物中５質量％以下であることが好ましく、２質量％以下であることがより好ましく、１質量％以下であることがさらに好ましい。添加剤としては、適宜、中和剤、酸化防止剤、熱安定剤、耐候剤、滑剤、紫外線吸収剤、帯電防止剤、アンチブロッキング剤、防曇剤、気泡防止剤、分散剤、難燃剤、抗菌剤、蛍光増白剤、架橋剤、架橋助剤等の添加剤、染料、顔料等の着色剤等が挙げられ、これらの中でも酸化防止剤が好ましい。 In addition, various additives used in this field can be added to the raw material composition used in the present invention as long as the effects of the present invention are not impaired. Specifically, 5% by mass of the raw material composition or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. Additives include neutralizing agents, antioxidants, heat stabilizers, weathering agents, lubricants, UV absorbers, antistatic agents, antiblocking agents, antifogging agents, antifogging agents, dispersants, flame retardants, Additives such as antibacterial agents, fluorescent whitening agents, cross-linking agents and cross-linking aids, coloring agents such as dyes and pigments, and the like, among which antioxidants are preferred.
＜溶融紡糸工程＞
　本発明に係るポリプロピレン繊維の製造方法は、まず、ポリプロピレンを含む原料組成物を溶融し、溶融物を所定の孔径を有する紡糸ノズルから押し出し、所定の紡糸速度に設定されたローラーで巻き取って未延伸糸を得る工程を含むことが好ましい。 <Melt spinning process>
In the method for producing a polypropylene fiber according to the present invention, first, a raw material composition containing polypropylene is melted, the melted product is extruded from a spinning nozzle having a predetermined hole diameter, and is wound by a roller set at a predetermined spinning speed to obtain an unspun fiber. It is preferable to include the step of obtaining a drawn yarn.
　ポリプロピレンを溶融押出する手段としては、当該技術分野で通常使用されるプラスチック繊維の溶融押出技術を使用すればよい。溶融押出する手段としては、限定するものではないが、例えば、原料プラスチックを加熱、溶融した後、該溶融物を加圧押出する押出機を挙げることができる。 As a means of melt-extrusion of polypropylene, a melt-extrusion technique for plastic fibers that is commonly used in the relevant technical field may be used. Means for melt extrusion are not limited, but for example, an extruder that heats and melts a raw material plastic and then presses and extrudes the melt can be used.
　ポリプロピレンの紡糸温度は使用されるポリプロピレンの融点以上であることが好ましく、（融点＋５０℃以上）、つまり融点温度から５０℃以上高い温度であることが好ましく、（融点＋７０℃～融点＋１５０℃）、つまり融点温度から７０℃高い温度～融点温度から１５０℃高い温度の範囲であることがより好ましい。本発明の高強度且つ高伸度の溶融紡糸ポリプロピレン繊維を得るためには、未延伸糸における重量平均分子量を出来る限り高くすることが必要である。このために、出来る限り高分子量の原料を用いることが好ましい。さらに、溶融流動時における分子量低下を出来る限り抑えることが必要となる。この観点から、押出機の温度が高すぎると、ポリプロピレンが劣化し、分子量が低下するため好ましくない。また、温度が低すぎると、流動性が低下するため、装置の破損やメルトフラクチャー等成形加工が困難となる恐れがあり、好ましくない。なお、ポリプロピレンの融点は１５０～１８０℃である。また、溶融流動時の分子量低下を抑制する方法としては、溶融滞留時間を短くしたり、酸化防止剤を添加したりする方法等を採用することも好ましい。 The spinning temperature of polypropylene is preferably at least the melting point of the polypropylene used (melting point +50° C. or higher), that is, it is preferably at least 50° C. higher than the melting point temperature (melting point +70° C. to melting point +150° C.), That is, it is more preferable to be in the range of 70° C. higher than the melting point to 150° C. higher than the melting point. In order to obtain the high-strength and high-elongation melt-spun polypropylene fiber of the present invention, it is necessary to increase the weight average molecular weight of the undrawn yarn as high as possible. For this reason, it is preferable to use raw materials having as high a molecular weight as possible. Furthermore, it is necessary to suppress the decrease in molecular weight as much as possible during melt flow. From this point of view, if the temperature of the extruder is too high, the polypropylene will deteriorate and the molecular weight will decrease, which is not preferable. On the other hand, if the temperature is too low, the fluidity is lowered, which may cause damage to the apparatus and difficulty in molding due to melt fracture, which is not preferable. The melting point of polypropylene is 150 to 180°C. As a method for suppressing the decrease in molecular weight during melt flow, it is also preferable to adopt a method such as shortening the melt residence time or adding an antioxidant.
　紡糸ノズルの単孔吐出量の上限は、１．０ｇ／ｍｉｎ以下であることが好ましく、０．５ｇ／ｍｉｎ以下であることがより好ましい。単孔吐出量をこの範囲より高くすると、メルトフラクチャー等が発生し、紡糸が不安定になる場合がある。また、紡糸ノズルの単孔吐出量の下限は特に限定されないが、生産性の観点から０．０５ｇ／ｍｉｎ以上が好ましく、０．１ｇ／ｍｉｎ以上がより好ましい。 The upper limit of the single-hole discharge rate of the spinning nozzle is preferably 1.0 g/min or less, more preferably 0.5 g/min or less. If the single-hole discharge rate is higher than this range, melt fracture or the like may occur, resulting in unstable spinning. The lower limit of the single-hole discharge rate of the spinning nozzle is not particularly limited, but from the viewpoint of productivity, it is preferably 0.05 g/min or more, more preferably 0.1 g/min or more.
　紡糸速度は、５０～７００ｍ／ｍｉｎであることが好ましく、１００～５００ｍ／ｍｉｎであることがより好ましい。この速度範囲で巻き取ることで、未延伸糸中の配向度や結晶構造等を制御することができ、結果として得られる繊維の強度が向上するため、好ましい。 The spinning speed is preferably 50-700 m/min, more preferably 100-500 m/min. By winding in this speed range, it is possible to control the degree of orientation, crystal structure, etc. in the undrawn yarn, and as a result, the strength of the obtained fiber is improved, which is preferable.
＜冷却工程＞
　本発明の製造方法は、得られた溶融紡糸された繊維（未延伸糸）を、使用されるポリプロピレンのガラス転移温度（Ｔｇ）～前記ガラス転移温度温度＋５０℃の温度範囲に冷却する工程を含む。 <Cooling process>
The production method of the present invention includes the step of cooling the obtained melt-spun fibers (undrawn fibers) to a temperature range of the glass transition temperature (Tg) of the polypropylene to be used to the glass transition temperature + 50 ° C. .
　未延伸糸は、溶融押出手段における加熱温度から所定の温度Ａ（ポリプロピレンのガラス転移温度（Ｔｇ）～前記ガラス転移温度温度＋５０℃）に急冷され、該温度Ａにおいて、引取りながら紡糸されることが好ましい。ここで温度Ａは、使用されるポリプロピレンのガラス転移温度（Ｔｇ）～（Ｔｇ＋５０℃）の範囲、つまりＴｇ温度からＴｇの５０℃上までの温度範囲であり、（Ｔｇ）～（Ｔｇ＋２５℃）の範囲の温度であることがより好ましく、さらに（Ｔｇ）～（Ｔｇ＋１０℃）の範囲の温度であることがさらに好ましい。なお、ポリプロピレンのＴｇは－２０℃～５℃である。冷却は、風冷あるいは冷媒（例えば、水、メタノール、エタノール、それらの混合溶媒）、又は風冷と冷媒の組み合わせ等の強制冷却手段を用いて行うことが可能である。 The undrawn yarn is rapidly cooled from the heating temperature in the melt extrusion means to a predetermined temperature A (the glass transition temperature (Tg) of polypropylene to the glass transition temperature + 50 ° C.), and is spun at this temperature A while being taken up. is preferred. Here, the temperature A is the range of the glass transition temperature (Tg) to (Tg + 50 ° C.) of the polypropylene used, that is, the temperature range from the Tg temperature to 50 ° C. above Tg, and (Tg) to (Tg + 25 ° C.). A temperature in the range is more preferable, and a temperature in the range of (Tg) to (Tg+10° C.) is even more preferable. The Tg of polypropylene is -20°C to 5°C. Cooling can be performed using forced cooling means such as air cooling or refrigerants (eg, water, methanol, ethanol, mixed solvents thereof), or a combination of air cooling and refrigerants.
＜延伸工程＞
　溶融紡糸工程によって得られた未延伸糸を冷却後、延伸工程によって延伸されて目的のポリプロピレン繊維を得ることができる。本発明において、未延伸糸の延伸は、当該技術分野で通常に使用される延伸手段を用いて行うことができる。例えば、送出ローラーと巻取ローラーとの速度差によって繊維を連続的に延伸できる。送出ローラーと巻取ローラーとの速度差によって延伸倍率が規定される。送出ローラーから引き出された未延伸糸は、所定の長さのオーブンで所定の温度に加熱されて延伸される。また、延伸は、１段階でもよく、複数段でもよい。 <Stretching process>
After cooling the undrawn yarn obtained by the melt spinning process, it is drawn by the drawing process to obtain the intended polypropylene fiber. In the present invention, drawing of the undrawn yarn can be carried out using a drawing means commonly used in the technical field. For example, the fiber can be drawn continuously by a speed difference between the delivery roller and the take-up roller. The draw ratio is defined by the speed difference between the delivery roller and the take-up roller. The unstretched yarn pulled out from the delivery roller is heated to a predetermined temperature in an oven of a predetermined length and stretched. Further, the stretching may be performed in one stage or in multiple stages.
　本工程において、延伸倍率には特に上限はなく、繊維が破断しない程度であればよい。具体的には、延伸倍率は、２倍以上であることが好ましく、５倍以上であることがより好ましい。 In this process, there is no particular upper limit to the draw ratio, as long as the fibers are not broken. Specifically, the draw ratio is preferably 2 times or more, more preferably 5 times or more.
　本工程において、未延伸糸を延伸する温度は、１５０℃以上１８０℃以下であり、１５０℃以上１７５℃以下が好ましく、１５５℃以上１７３℃以下がより好ましく、１６０℃以上１７３℃以下が最も好ましい。温度を掛けながら変形させることにより、ポリプロピレン繊維の融点が向上し、融点近傍での安定的な延伸が可能になり、比較的高温での延伸が可能となる。このことにより、結晶化度が比較的高く、熱収縮率の比較的低い繊維を得ることが可能となる。延伸温度が１５０℃未満の場合には、得られる繊維の結晶化度が低くなり、高強度、且つ高伸度であるポリプロピレン繊維を得ることが困難になる。 In this step, the temperature for drawing the undrawn yarn is 150° C. or higher and 180° C. or lower, preferably 150° C. or higher and 175° C. or lower, more preferably 155° C. or higher and 173° C. or lower, and most preferably 160° C. or higher and 173° C. or lower. . By deforming while applying temperature, the melting point of the polypropylene fiber is increased, and stable drawing near the melting point becomes possible, and drawing at a relatively high temperature becomes possible. This makes it possible to obtain fibers with relatively high crystallinity and relatively low thermal shrinkage. If the drawing temperature is lower than 150° C., the crystallinity of the resulting fiber will be low, making it difficult to obtain a polypropylene fiber with high strength and high elongation.
　また、前記延伸温度は、（ガラス転移温度（Ｔｇ）＋１５０℃）～（Ｔｇ＋２００℃）の温度範囲、つまり、未延伸糸のＴｇの１５０℃上の温度からＴｇの２００℃上の温度範囲であることが好ましい。なお、本発明にかかる未延伸糸のＴｇは、０～２０℃である。 The drawing temperature is in the temperature range from (glass transition temperature (Tg) + 150°C) to (Tg + 200°C), that is, the temperature range from 150°C above the Tg of the undrawn yarn to 200°C above the Tg. is preferred. The undrawn yarn according to the present invention has a Tg of 0 to 20°C.
　送出ローラー速度、巻取ローラー速度、オーブン長は以下の式に示す変形速度が０．００１ｓｅｃ－１以上０．１ｓｅｃ－１未満になるように調整するものであり、０．００１ｓｅｃ－１以上０．０５ｓｅｃ－１以下にすることが好ましい。この範囲より高い変形速度で延伸すると、高分子量であるポリマーの変形が延伸の変形速度に追い付かず、延伸性が低下する。また、この範囲より低い変形速度で延伸すると、生産性が低下する。この変形速度の範囲内に調整することで、均一な延伸が可能となるため延伸倍率が向上し、結果として得られる繊維の強度が向上する。
　変形速度（ｓｅｃ－１）＝［巻取ローラー速度（ｍ／ｓｅｃ）－送出ローラー速度（ｍ／ｓｅｃ）］／オーブン長（ｍ） The delivery roller speed, take-up roller speed, and oven length are adjusted so that the deformation speed shown in the following formula is 0.001 sec −1 or more and less than 0.1 sec −1 , and 0.001 sec −1 or more and 0.001 sec −1 or more and less than 0.1 sec −1 . 05 sec −1 or less is preferable. If the deformation rate is higher than this range, the deformation rate of the high-molecular-weight polymer cannot catch up with the deformation rate of the drawing, resulting in a decrease in drawability. In addition, stretching at a deformation rate lower than this range lowers productivity. By adjusting the deformation speed within this range, uniform drawing becomes possible, so that the draw ratio is improved and the strength of the resulting fiber is improved.
Deformation speed (sec -1 ) = [winding roller speed (m/sec) - delivery roller speed (m/sec)]/oven length (m)
　高分子量ポリマーを用いて高強度繊維を得るための課題として延伸が挙げられる。一般的に、高分子量ポリマーを用いると延伸が阻害されて延伸しにくくなる傾向がある。この原因としては、高分子量ポリマーになると緩和時間が長くなることが原因として考えられている。そこで、本発明では、融点近傍の比較的高温の延伸温度である１５０～１８０℃を採用し、高分子量のポリマーの緩和時間に対応した低変形速度で延伸することで、均一且つ高倍率での延伸が可能となり、またその結果として分子鎖が高度に配向していることから、強度、伸度に優れ、比較的良好な生産性を兼ね備えた繊維を得ることに成功した。また、高分子量ポリマーを用いていることから、得られた繊維の融点が高くなり、高度に配向していることから、結晶化度が高くなり、完成糸の分子量も向上した効果も加味されて加熱時にクリープしにくく、熱収縮しにくい、熱安定性に優れる繊維が得られた。 Drawing is one of the challenges in obtaining high-strength fibers using high-molecular-weight polymers. In general, the use of a high-molecular-weight polymer tends to hinder stretching and make it difficult to stretch. The reason for this is thought to be that the relaxation time becomes longer when the polymer has a higher molecular weight. Therefore, in the present invention, a drawing temperature of 150 to 180° C., which is a relatively high temperature near the melting point, is adopted, and the drawing is performed at a low deformation rate corresponding to the relaxation time of the polymer with a high molecular weight. Drawing is possible, and as a result, the molecular chains are highly oriented, so we have succeeded in obtaining a fiber that has both excellent strength and elongation and relatively good productivity. In addition, since a high-molecular-weight polymer is used, the melting point of the obtained fiber is high, and since it is highly oriented, the degree of crystallinity is high, and the molecular weight of the finished yarn is also improved. A fiber was obtained which was resistant to creep when heated, resistant to thermal shrinkage, and excellent in thermal stability.
　本発明のポリプロピレン繊維の製造方法は、前述の通り、溶融紡糸工程、冷却工程、延伸工程を含むものであるが、その他の工程を本発明の効果を損なわない範囲で含んでいてもよい。また、本発明の製造方法においては、比較的高温の延伸温度（１５０～１８０℃）を採用するものであるため、延伸後に熱処理する必要がなく、延伸後の熱処理工程を含まないものである。 As described above, the method for producing polypropylene fibers of the present invention includes a melt spinning step, a cooling step, and a drawing step, but may include other steps within a range that does not impair the effects of the present invention. In addition, since the production method of the present invention employs a relatively high stretching temperature (150 to 180° C.), it does not require heat treatment after stretching, and does not include a heat treatment step after stretching.
　前記製造方法により得られたポリプロピレン繊維の破断強度、破断伸度、重量平均分子量、クリープ速度、乾熱収縮率、結晶化度は、前記範囲内になるものである。 The breaking strength, breaking elongation, weight average molecular weight, creep rate, dry heat shrinkage, and crystallinity of the polypropylene fiber obtained by the above production method are within the above ranges.
　また、本発明の製造方法においては、原料ポリプロピレン樹脂から最終的に得られた繊維になるまでの分子量低下が抑制されているものであり、分子量低下率（（原料ポリプロピレン樹脂の重量平均分子量－最終的に得られた繊維の重量平均分子量）／原料ポリプロピレン樹脂の重量平均分子量×１００）が、３５％以下であることが好ましく、２５％以下であることがより好ましく、２０％以下であることがさらに好ましく、１５％以下であることが特に好ましい。 In addition, in the production method of the present invention, the molecular weight reduction from the raw material polypropylene resin to the finally obtained fiber is suppressed, and the molecular weight reduction rate ((weight average molecular weight of the raw material polypropylene resin - final The weight average molecular weight of the obtained fiber) / weight average molecular weight of the raw material polypropylene resin × 100) is preferably 35% or less, more preferably 25% or less, and 20% or less. More preferably, it is particularly preferably 15% or less.
　以下、実施例及び比較例を示して本発明をより具体的に説明するが、本発明は以下の実施例によって限定されるものではない。なお、以下の実施例における物性等の評価方法は以下の通りである。 The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited by the following examples. The methods for evaluating physical properties and the like in the following examples are as follows.
（１）重量平均分子量
　重量平均分子量は、東ソー株式会社製の高温ＧＰＣ測定器ＨＬＣ－８３２１ＧＰＣ／ＨＴを用い、以下のように測定した。
　溶媒にｏ－ジクロロベンゼンを用い、ポリプロピレンの濃度が０．１２質量％になるように調整した。また、酸化防止剤としてジブチルヒドキシトルエンを０．０５質量％添加し、測定試料とした。カラムにＷａｔｅｒｓ　Ｓｙｔｒａｇｅｌ　ＨＴ　３，４，６Ｅを用い、測定温度を１４０℃に設定した。測定器に測定試料を２００μＬ注入し、流速：０．３ｍＬ／ｍｉｎで測定した。検出器にはＲＩ（ポラリティー（－））を用いた。 (1) Weight Average Molecular Weight The weight average molecular weight was measured using a high-temperature GPC analyzer HLC-8321GPC/HT manufactured by Tosoh Corporation as follows.
Using o-dichlorobenzene as a solvent, the concentration of polypropylene was adjusted to 0.12% by mass. Further, 0.05% by mass of dibutylhydroxytoluene was added as an antioxidant to prepare a measurement sample. Waters Sytragel HT 3,4,6E was used for the column, and the measurement temperature was set to 140°C. 200 μL of the measurement sample was injected into the measuring device, and the measurement was performed at a flow rate of 0.3 mL/min. RI (polarity (−)) was used as a detector.
（２）繊度
　サンプルを位置の異なる５箇所で各々１０ｍになるようにカットし、その質量を測定しその平均値を１００００ｍに換算して繊度（ｄｔｅｘ）とした。 (2) Fineness A sample was cut into 10 m lengths at five different positions, the mass was measured, and the average value was converted to 10000 m to obtain fineness (dtex).
（３）引張試験
　ＪＩＳ　Ｌ　１０１３　８．５．１に準拠して測定した。但し、つかみ間隔は１５０ｍｍ、引張速度は１５０ｍｍ／ｍｉｎとした。最大点での応力を破断強度、最大点応力における伸びを破断伸度、曲線の原点付近の最大勾配を与える接線から弾性率を計算して求めた。 (3) Tensile test Measured according to JIS L 1013 8.5.1. However, the grip interval was 150 mm, and the pulling speed was 150 mm/min. The stress at the maximum point was calculated as the breaking strength, the elongation at the maximum point stress was calculated as the breaking elongation, and the elastic modulus was calculated from the tangent line giving the maximum gradient near the origin of the curve.
（４）クリープ速度
　図１及び図２に示す通り、試料１の自由端の片端を固定し、もう一方の自由端に所定荷重３をかけて、その試料１の両端間の部分を所定温度に加熱し、測定時間毎に試料の変化量を読み取ってクリープを測定した。具体的な測定法は以下の通りである。
　所定温度（本実施例では７０℃）に加熱し、その温度を維持することができる金属板２（長さ７０．０ｃｍ、表面は鏡面加工）を準備した。
　試料１は、撚りをかけずに上記金属板２の上に接触するように載せた。
　図１に示すように上記試料１の自由端のうち一方側を金属板２から出た部分で固定し（試料の固定端４）、もう一方の自由端は、上記金属板２から出た部分で初期荷重（荷重：０．２ｇ／ｄｔｅｘ）をかけた。
　上記金属板２上の試料１に試料長５０．０ｃｍの距離となるよう印を２箇所付けた後、上記初期荷重を取り外して所定荷重３（破断強度の２０％）を取り付けた。次に、図２に示すように上記金属板２上の試料１に接触しないように保温のため上側から蓋５を閉めて（蓋５と試料１は接触していない）、クリープの測定を開始し、測定開始から１時間、２時間、３時間、４時間、５時間で、蓋５を開けて測定した。
　ここで、ある時刻ｔにおける試料の伸びＬｉ（ｍｍ）は、その時刻ｔでの試料１に付けた印間距離Ｌ（ｔ）と最初に付けた試料１の印間距離Ｌ０（５０．０ｃｍ）との差であり、次のように示される。
εｉ（ｔ）（％）＝（Ｌ（ｔ）－Ｌ０）×１００／Ｌ０
　また、クリープ速度τ（ｓｅｃ－１）は時間１秒当たりの試料の長さの変化と定義され、測定時間毎のクリープ速度τｉは次のように示される。
τｉ（ｓｅｃ－１）＝［（εｉ－εｉ－１）／（ｔｉ－ｔｉ－１）］／１００
　上記のとおり測定開始から５時間後まで印間の距離を測定し、測定時間毎のクリープ速度τｉを対数目盛上にプロットし、その極小値を、測定した試料のクリープ速度とした。
　測定開始～１時間後、～２時間後、～３時間後、～４時間後、～５時間後と計５回の測定となるが、各回（１時間）で伸長した試料の伸び量が有効測定範囲の０．５ｍｍを下回る微小変化となった場合は、その回の測定は除外する。
　クリープ速度は２回測定して得られた数値の平均を用いた。 (4) Creep rate As shown in FIGS. 1 and 2, one free end of the sample 1 is fixed, a predetermined load 3 is applied to the other free end, and the portion between both ends of the sample 1 is heated to a predetermined temperature. The creep was measured by heating and reading the amount of change in the sample at each measurement time. A specific measuring method is as follows.
A metal plate 2 (70.0 cm long, mirror-finished surface) capable of being heated to a predetermined temperature (70° C. in this example) and maintained at that temperature was prepared.
The sample 1 was placed on the metal plate 2 without being twisted so as to be in contact therewith.
As shown in FIG. 1, one of the free ends of the sample 1 is fixed at the portion protruding from the metal plate 2 (fixed end 4 of the sample), and the other free end is the portion protruding from the metal plate 2. was applied with an initial load (load: 0.2 g/dtex).
After marking two points on the sample 1 on the metal plate 2 so that the sample length was 50.0 cm, the initial load was removed and a predetermined load 3 (20% of the breaking strength) was applied. Next, as shown in FIG. 2, the cover 5 is closed from the upper side for heat retention so that the sample 1 on the metal plate 2 does not touch (the cover 5 and the sample 1 are not in contact), and creep measurement is started. After 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours from the start of the measurement, the lid 5 was opened and the measurement was performed.
Here, the elongation L i (mm) of the sample at a certain time t is the distance L (t) between the marks attached to the sample 1 at that time t and the distance L 0 (50. 0 cm) and is expressed as follows.
ε i (t) (%) = (L (t) - L 0 ) x 100/L 0
Also, the creep rate τ(sec −1 ) is defined as the change in length of the sample per second of time, and the creep rate τ i for each measurement time is expressed as follows.
τ i (sec −1 )=[(ε i −ε i−1 )/(t i −t i−1 )]/100
As described above, the distance between the marks was measured from the start of the measurement until 5 hours later, the creep rate τi for each measurement time was plotted on a logarithmic scale, and the minimum value was taken as the measured creep rate of the sample.
After 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours from the start of measurement, a total of 5 measurements were taken. If there is a minute change of less than 0.5 mm of the measurement range, the measurement is excluded.
The average of the values obtained by measuring twice was used for the creep rate.
（５）乾熱収縮率
　ＪＩＳ　Ｌ　１０１３　８．１８．２ｂ）に準拠し、１４０℃の空気中に３０分暴露し、乾熱収縮率を測定した。乾熱収縮率は、３回測定して得られた数値の平均を用いた。 (5) Dry Heat Shrinkage According to JIS L 1013 8.18.2b), the film was exposed to air at 140° C. for 30 minutes, and the dry heat shrinkage was measured. As the dry heat shrinkage rate, the average value obtained by measuring three times was used.
（６）結晶化度
　ＴＡインスツルメンツ製の示差走査熱量測定器ＤＳＣ２５を用いて測定を行った。結晶化度は、高分子中の結晶領域が占める割合として、以下の式で算出した。なお、完全結晶体融解熱量は、結晶化度が１００％時の融解熱量で、ポリプロピレンは２０９Ｊ／ｇとした。
　結晶化度（％）＝（測定融解熱量／完全結晶体融解熱量）×１００
　試料を３～５ｍｍ以下に切断し、アルミパンに約２ｍｇ充填、封入し、同様の空のアルミパンをリファレンスとして、窒素ガス雰囲気下で、３０℃から１０℃／ｍｉｎの昇温速度で２５０℃まで昇温し、得られた吸熱ピークの面積を測定融解熱量とした。結晶化度は２回測定して得られた数値の平均を用いた。 (6) Crystallinity Measured using a differential scanning calorimeter DSC25 manufactured by TA Instruments. The degree of crystallinity was calculated by the following formula as the ratio of crystalline regions in the polymer. The heat of fusion of a complete crystal is the heat of fusion when the degree of crystallinity is 100%, and polypropylene is 209 J/g.
Crystallinity (%) = (measured heat of fusion/heat of fusion of complete crystal) x 100
Cut the sample to 3 to 5 mm or less, fill and seal about 2 mg in an aluminum pan, and use a similar empty aluminum pan as a reference, under a nitrogen gas atmosphere, from 30 ° C. to 250 ° C. at a rate of 10 ° C./min. The area of the obtained endothermic peak was taken as the measured heat of fusion. The average of the values obtained by measuring twice was used for the degree of crystallinity.
（７）融点
　ＴＡインスツルメンツ製の示差走査熱量測定器ＤＳＣ２５を用いて測定を行った。試料を３～５ｍｍ以下に切断し、アルミパンに約２ｍｇ充填、封入し、同様の空のアルミパンをリファレンスとして、窒素ガス雰囲気下で、３０℃から１０℃／ｍｉｎの昇温速度で２５０℃まで昇温し、得られた吸熱ピークトップの温度を融点とした。融点は２回測定して得られた数値の平均を用いた。 (7) Melting point Measurement was performed using a differential scanning calorimeter DSC25 manufactured by TA Instruments. Cut the sample to 3 to 5 mm or less, fill and seal about 2 mg in an aluminum pan, and use a similar empty aluminum pan as a reference, under a nitrogen gas atmosphere, from 30 ° C. to 250 ° C. at a rate of 10 ° C./min. The temperature at the endothermic peak top obtained was taken as the melting point. As the melting point, the average of the values obtained by measuring twice was used.
（８）ペンタッド（ｍｍｍｍ）分率
　共鳴周波数６００ＭＨｚのＢＲＵＫＥＲ社製のＮＭＲ装置ＡＶＡＮＣＥ－ＮＥＯを用いて１３Ｃ－ＮＭＲ測定を行った。試料濃度が５０ｍｇ／０．６ｍｌとなるように（ベンゼン－ｄ６：ｏ－ジクロロベンゼン＝２０：８０）混合溶媒に試料を１３５℃で溶解させ、測定モード：プロトンデカップリング法、パルス幅：３．６７ｕｓｅｃ、パルス繰り返し時間：２．５ｓｅｃ、積算回数：１６００回、測定温度：１２０℃の条件下で測定した。ペンタッド（ｍｍｍｍ）分率Ｆ（ｍｍｍｍ）は次のように示される。
Ｆ（ｍｍｍｍ）＝Ｉｍｍｍｍ／［Ｉｍｍｍｍ＋Ｉｍｍｍｒ＋Ｉｒｍｍｒ＋Ｉｍｍｒｒ＋Ｉｒｍｒｒ＋Ｉｒｍｒｍ＋Ｉｍｍｒｍ＋Ｉｒｒｒｒ＋Ｉｍｒｒｒ＋Ｉｍｒｒｍ］
　ここで、Ｉｘｘｘｘ（ｘはｍ又はｒ）は、１３Ｃ－ＮＭＲスペクトルにおいて、ｏ－ジクロロベンゼンの１，２位のピークを１３２．６ｐｐｍとしたとき、ｘｘｘｘペンタッドに帰属される化学シフトが１９～２２ｐｐｍのメチル領域のピーク面積を示す。 (8) Pentad (mmmm) Fraction 13 C-NMR measurement was performed using an NMR apparatus AVANCE-NEO manufactured by BRUKER with a resonance frequency of 600 MHz. The sample was dissolved in a mixed solvent (benzene-d6:o-dichlorobenzene=20:80) at 135° C. so that the sample concentration was 50 mg/0.6 ml, measurement mode: proton decoupling method, pulse width: 3. Measurement was performed under conditions of 67 usec, pulse repetition time: 2.5 sec, number of times of accumulation: 1600, and measurement temperature: 120°C. The pentad (mmmm) fraction F (mmmm) is expressed as follows.
F (mmmm) = Immmm/[Immmm+Immmr+Irmmr+Immrr+Irmrr+Irmrm+Immrm+Irrrr+Imrrr+Imrrm]
Here, Ixxxx (x is m or r) is a chemical shift of 19 to The peak area of the methyl region at 22 ppm is shown.
（実施例１）
　市販のポリプロピレン樹脂（サンアロマー株式会社製、ＶＳ２００Ａ、ＭＦＲ：０．４５ｇ／１０ｍｉｎ、重量平均分子量：９．５×１０５）を用いて、紡糸温度：２９５℃、単孔吐出量：０．２６ｇ／ｍｉｎの条件で、孔径φ０．４ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２３℃の冷却風を糸走行方向に対して垂直方向から０．５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：２５０ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１７１℃、変形速度：０．０２ｓｅｃ－１の条件で６．５倍延伸し、ポリプロピレン繊維１を得た。物性を表１に示す。 (Example 1)
Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 × 10 5 ), spinning temperature: 295 ° C., single hole discharge rate: 0.26 g / It is melt extruded from a spinneret with a hole diameter of φ0.4 mm under the conditions of min, and cooled and solidified by blowing cooling air with a quenching temperature of 23° C. at 0.5 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.5 times under the conditions of drawing temperature: 171° C. and deformation speed: 0.02 sec −1 to obtain polypropylene fiber 1 . Physical properties are shown in Table 1.
（実施例２）
　市販のポリプロピレン樹脂（サンアロマー株式会社製、ＶＳ２００Ａ、ＭＦＲ：０．４５ｇ／１０ｍｉｎ、重量平均分子量：９．５×１０５）を用いて、紡糸温度：２９５℃、単孔吐出量：０．２０ｇ／ｍｉｎの条件で、孔径φ０．４ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２０℃の冷却風を糸走行方向に対して垂直方向から０．５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：５００ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１７１℃、変形速度：０．０２ｓｅｃ－１の条件で６．０倍延伸し、ポリプロピレン繊維２を得た。物性を表１に示す。 (Example 2)
Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 × 10 5 ), spinning temperature: 295 ° C., single hole discharge rate: 0.20 g / It is melt extruded from a spinneret with a hole diameter of φ0.4 mm under the conditions of min, and cooled and solidified by blowing a cooling air with a quenching temperature of 20° C. at 0.5 m/sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 500 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 171° C. and deformation speed: 0.02 sec −1 to obtain polypropylene fiber 2 . Physical properties are shown in Table 1.
（実施例３）
　市販のポリプロピレン樹脂（サンアロマー株式会社製、ＶＳ２００Ａ、ＭＦＲ：０．４５ｇ／１０ｍｉｎ、重量平均分子量：９．５×１０５）を用いて、紡糸温度：２９１℃、単孔吐出量：０．２１ｇ／ｍｉｎの条件で、孔径φ０．４ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２０℃の冷却風を糸走行方向に対して垂直方向から０．５５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：２５０ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１７２℃、変形速度：０．０１ｓｅｃ－１の条件で６．０倍延伸し、ポリプロピレン繊維３を得た。物性を表１に示す。 (Example 3)
Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 × 10 5 ), spinning temperature: 291 ° C., single hole discharge rate: 0.21 g / It is melt extruded from a spinneret with a hole diameter of φ0.4 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 20 ° C. at 0.55 m / sec perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 172° C. and deformation rate: 0.01 sec −1 to obtain polypropylene fiber 3 . Physical properties are shown in Table 1.
（実施例４）
　市販のポリプロピレン樹脂（サンアロマー株式会社製、ＶＳ２００Ａ、ＭＦＲ：０．４５ｇ／１０ｍｉｎ、重量平均分子量：９．５×１０５）を用いて、紡糸温度：２９１℃、単孔吐出量：０．２１ｇ／ｍｉｎの条件で、孔径φ０．４ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２０℃の冷却風を糸走行方向に対して垂直方向から０．６ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：２５０ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１７２℃、変形速度：０．０４ｓｅｃ－１の条件で６．０倍延伸し、ポリプロピレン繊維４を得た。物性を表１に示す。 (Example 4)
Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 × 10 5 ), spinning temperature: 291 ° C., single hole discharge rate: 0.21 g / It is melt extruded from a spinneret with a hole diameter of φ0.4 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 20 ° C. at 0.6 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.0 times under the conditions of drawing temperature: 172° C. and deformation speed: 0.04 sec −1 to obtain polypropylene fiber 4 . Physical properties are shown in Table 1.
（実施例５）
　市販のポリプロピレン樹脂（サンアロマー株式会社製、ＶＳ２００Ａ、ＭＦＲ：０．４５ｇ／１０ｍｉｎ、重量平均分子量：９．５×１０５）を用いて、紡糸温度：２９６℃、単孔吐出量：０．２６ｇ／ｍｉｎの条件で、孔径φ０．３ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２３℃の冷却風を糸走行方向に対して垂直方向から０．６ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：２５０ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１５１℃、変形速度：０．０２ｓｅｃ－１の条件で６．５倍延伸し、ポリプロピレン繊維５を得た。物性を表１に示す。 (Example 5)
Using a commercially available polypropylene resin (manufactured by SunAllomer Co., Ltd., VS200A, MFR: 0.45 g/10 min, weight average molecular weight: 9.5 × 10 5 ), spinning temperature: 296 ° C., single hole discharge rate: 0.26 g / It is melt extruded from a spinneret with a hole diameter of φ0.3 mm under the condition of min, and cooled and solidified by blowing cooling air with a quenching temperature of 23 ° C. at 0.6 m / sec in the direction perpendicular to the yarn running direction. was taken up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 6.5 times under the conditions of drawing temperature: 151° C. and deformation speed: 0.02 sec −1 to obtain polypropylene fiber 5 . Physical properties are shown in Table 1.
（実施例６）
　市販のポリプロピレン樹脂（日本ポリプロ株式会社製、ＥＡ９、ＭＦＲ：０．５ｇ／１０ｍｉｎ、重量平均分子量：９．２×１０５）を用いて、紡糸温度：２９５℃、単孔吐出量：０．２７ｇ／ｍｉｎの条件で、孔径φ０．６ｍｍの紡糸口金から溶融押し出しし、クエンチ温度１８℃の冷却風を糸走行方向に対して垂直方向から０．５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：３７５ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１７２℃、変形速度：０．０１ｓｅｃ－１の条件で５．５倍延伸し、ポリプロピレン繊維６を得た。物性を表１に示す。 (Example 6)
Using a commercially available polypropylene resin (manufactured by Japan Polypropylene Corporation, EA9, MFR: 0.5 g/10 min, weight average molecular weight: 9.2 × 10 5 ), spinning temperature: 295 ° C., single hole discharge amount: 0.27 g /min, melt extruded from a spinneret with a hole diameter of φ0.6 mm, and cooled and solidified by blowing a cooling wind with a quenching temperature of 18 ° C. at 0.5 m / sec in the direction perpendicular to the yarn running direction, This was wound up at a spinning speed of 375 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 5.5 times under the conditions of drawing temperature: 172° C. and deformation rate: 0.01 sec −1 to obtain polypropylene fiber 6 . Physical properties are shown in Table 1.
（実施例７）
　市販のポリプロピレン樹脂（日本ポリプロ株式会社製、ＥＡ９、ＭＦＲ：０．５ｇ／１０ｍｉｎ、重量平均分子量：９．２×１０５）に、酸化防止剤として、Ｓｕｍｉｌｉｚｅｒ　ＧＡ－８０（住友化学株式会社製）を０．１質量％とＡＤＥＫＡ　ＳＴＡＢ　ＰＥＰ－３６（株式会社ＡＤＥＫＡ製）を０．２質量％とそれぞれの重量比率になるように添加した原料を用いて、紡糸温度：２９５℃、単孔吐出量：０．２３ｇ／ｍｉｎの条件で、孔径φ０．６ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２２℃の冷却風を糸走行方向に対して垂直方向から０．５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：４００ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１６５℃、変形速度：０．０１ｓｅｃ－１の条件で５．０倍延伸し、ポリプロピレン繊維７を得た。物性を表１に示す。 (Example 7)
Sumilizer GA-80 (manufactured by Sumitomo Chemical Co., Ltd.) was added to a commercially available polypropylene resin (manufactured by Japan Polypropylene Corporation, EA9, MFR: 0.5 g/10 min, weight average molecular weight: 9.2 × 10 5 ) as an antioxidant. 0.1% by mass and 0.2% by mass of ADEKA STAB PEP-36 (manufactured by ADEKA Co., Ltd.). : Melt extruded from a spinneret with a hole diameter of φ0.6 mm under the condition of 0.23 g / min, and cooled and solidified by blowing cooling air with a quench temperature of 22 ° C. at 0.5 m / sec perpendicular to the yarn running direction After being drawn, it was taken up at a spinning speed of 400 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 5.0 times under the conditions of drawing temperature: 165° C. and deformation rate: 0.01 sec −1 to obtain polypropylene fiber 7 . Physical properties are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（比較例１）
　実施例１で得た未延伸糸を、延伸温度：１７１℃、変形速度：０．２０ｓｅｃ－１の条件で延伸したところ、最大５．０倍までしか延伸できなかった。５．０倍延伸して得られたポリプロピレン繊維８の物性を表２に示す。 (Comparative example 1)
When the undrawn yarn obtained in Example 1 was drawn under the conditions of a drawing temperature of 171° C. and a deformation rate of 0.20 sec −1 , it could only be drawn up to a maximum of 5.0 times. Table 2 shows the physical properties of the polypropylene fiber 8 obtained by drawing 5.0 times.
（比較例２）
　市販のポリプロピレン樹脂（日本ポリプロ株式会社製、ＦＹ６、ＭＦＲ：２．５ｇ／１０ｍｉｎ、重量平均分子量：６．２×１０５）を用いて、紡糸温度：２９５℃、単孔吐出量：０．２０ｇ／ｍｉｎの条件で、孔径φ０．４ｍｍの紡糸口金から溶融押し出しし、クエンチ温度２０℃の冷却風を糸走行方向に対して垂直方向から０．５ｍ／ｓｅｃで吹かせて冷却固化せしめた後に、これを紡糸速度：２５０ｍ／ｍｉｎで巻き取り、未延伸糸を得た。この未延伸糸を、延伸温度：１５８℃、変形速度：０．０２ｓｅｃ－１の条件で８．０倍延伸し、ポリプロピレン繊維９を得た。物性を表２に示す。 (Comparative example 2)
Using a commercially available polypropylene resin (manufactured by Japan Polypropylene Corporation, FY6, MFR: 2.5 g/10 min, weight average molecular weight: 6.2 × 10 5 ), spinning temperature: 295 ° C., single hole discharge amount: 0.20 g /min, the melt is extruded from a spinneret with a hole diameter of φ0.4 mm, and cooled and solidified by blowing cooling air with a quenching temperature of 20 ° C. at 0.5 m / sec in the direction perpendicular to the yarn running direction, This was wound up at a spinning speed of 250 m/min to obtain an undrawn yarn. This undrawn yarn was drawn 8.0 times under the conditions of drawing temperature: 158° C. and deformation speed: 0.02 sec −1 to obtain polypropylene fiber 9 . Physical properties are shown in Table 2.
（比較例３）
　実施例４で得た未延伸糸を、延伸温度：１７２℃、変形速度：０．１２ｓｅｃ－１の条件で４．５倍延伸し、ポリプロピレン繊維１０を得た。物性を表２に示す。 (Comparative Example 3)
The undrawn yarn obtained in Example 4 was drawn 4.5 times under the conditions of drawing temperature: 172° C. and deformation speed: 0.12 sec −1 to obtain polypropylene fiber 10 . Physical properties are shown in Table 2.
（比較例４）
　実施例５で得た未延伸糸を、延伸温度：１２１℃、変形速度：０．０１ｓｅｃ－１の条件で５．０倍延伸し、ポリプロピレン繊維１１を得た。物性を表２に示す。 (Comparative Example 4)
The undrawn yarn obtained in Example 5 was drawn 5.0 times under the conditions of drawing temperature: 121° C. and deformation rate: 0.01 sec −1 to obtain polypropylene fiber 11 . Physical properties are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１、２から明らかなように、実施例においては、高分子量のポリプロピレンを原料に用いて溶融紡糸し、延伸温度、変形速度を制御することにより、高結晶化度であり、高強度、高伸度であり、且つ高い熱安定性を有する溶融紡糸ポリプロピレン繊維が得られた。一方、比較例１、３では、高い変形速度で延伸した結果、得られたポリプロピレン繊維の伸度は優れるものの、結晶化度が低く、強度が劣るものであった。また、熱安定性の面でも十分なものではなかった。比較例２では、原料であるポリプロピレンの重量平均分子量が低く、その結果、得られたポリプロピレン繊維の重量平均分子量も低くなり、結晶化度も低く、強度が劣るものであった。また、熱安定性の面でも十分なものではなかった。比較例４では、延伸時の温度が低く、その結果、得られたポリプロピレン繊維の伸度は優れるものの、結晶化度が低く、強度が劣るものであった。また、熱安定性の面でも十分なものではなかった。 As is clear from Tables 1 and 2, in the examples, high-molecular-weight polypropylene was used as a raw material and melt-spun, and the stretching temperature and deformation rate were controlled to achieve high crystallinity, high strength, and high A melt-spun polypropylene fiber was obtained which was elongation and had high thermal stability. On the other hand, in Comparative Examples 1 and 3, as a result of stretching at a high deformation rate, the obtained polypropylene fibers had excellent elongation, but low crystallinity and inferior strength. In addition, the thermal stability was not sufficient. In Comparative Example 2, the raw material polypropylene had a low weight average molecular weight, and as a result, the obtained polypropylene fiber had a low weight average molecular weight, low crystallinity, and poor strength. In addition, the thermal stability was not sufficient. In Comparative Example 4, the temperature during drawing was low, and as a result, although the elongation of the obtained polypropylene fiber was excellent, the degree of crystallinity was low and the strength was inferior. In addition, the thermal stability was not sufficient.
　本発明により、高強度、高伸度、高結晶化度のポリプロピレン繊維を製造することが可能となる。本発明のポリプロピレン繊維は、繊維強化樹脂用の強化繊維、ロープ、釣糸等に好適である。 The present invention makes it possible to produce polypropylene fibers with high strength, high elongation, and high crystallinity. The polypropylene fiber of the present invention is suitable for reinforcing fibers for fiber-reinforced resins, ropes, fishing lines and the like.
クリープ速度の測定装置（蓋を開けた状態）Creep rate measuring device (with lid open) クリープ速度の測定装置（蓋を閉じた状態）Creep rate measuring device (cover closed)
１．試料
２．金属板
３．荷重
４．試料の固定端
５．蓋
  1. Sample 2. metal plate3. load4. Fixed end of sample5. lid

Claims (5)

  1. 　破断強度が１２．５ｃＮ／ｄｔｅｘ以上、破断伸度が１５％以上、重量平均分子量が６．０×１０５以上、且つ結晶化度が６４％以上であることを特徴とするポリプロピレン繊維。 A polypropylene fiber having a breaking strength of 12.5 cN/dtex or more, a breaking elongation of 15% or more, a weight average molecular weight of 6.0×10 5 or more, and a crystallinity of 64% or more.
  2. 　測定温度が７０℃、測定荷重が破断強度の２０％に相当する荷重におけるクリープ測定において、クリープ速度が１．０×１０－６ｓｅｃ－１以下であることを特徴とする請求項１に記載のポリプロピレン繊維。 2. The creep measurement according to claim 1, wherein the creep rate is 1.0×10 −6 sec −1 or less in creep measurement at a measurement temperature of 70° C. and a load corresponding to 20% of the breaking strength. polypropylene fibre.
  3. 　処理温度が１４０℃、処理時間が３０分における乾熱収縮測定において、乾熱収縮率が４％以下であることを特徴とする請求項１又は２に記載のポリプロピレン繊維。 The polypropylene fiber according to claim 1 or 2, characterized in that the dry heat shrinkage rate is 4% or less in a dry heat shrinkage measurement at a treatment temperature of 140°C and a treatment time of 30 minutes.
  4. 　弾性率が、１３０ｃＮ／ｄｔｅｘ以上であることを特徴とする請求項１又は２に記載のポリプロピレン繊維。 The polypropylene fiber according to claim 1 or 2, characterized by having an elastic modulus of 130 cN/dtex or more.
  5. 　繊維化後の重量平均分子量が６．０×１０５以上であるポリプロピレンを溶融紡糸した後、
    　使用されるポリプロピレンのガラス転移温度～前記ガラス転移温度温度＋５０℃の温度範囲に冷却した後、
    　１５０℃以上１８０℃以下の延伸温度において、変形速度が０．００１ｓｅｃ－１以上０．１ｓｅｃ－１未満で延伸したことを特徴とする、請求項１又は２に記載したポリプロピレン繊維の製造方法。
     
          After melt-spinning a polypropylene having a weight-average molecular weight of 6.0×10 5 or more after fiberization,
    After cooling to a temperature range from the glass transition temperature of the polypropylene used to the glass transition temperature + 50 ° C.,
    3. The method for producing a polypropylene fiber according to claim 1, wherein the fiber is drawn at a deformation rate of 0.001 sec −1 or more and less than 0.1 sec −1 at a drawing temperature of 150° C. or higher and 180° C. or lower.
PCT/JP2022/036940 2021-10-28 2022-10-03 High-strength, high-elongation polypropylene fiber and production method thereof WO2023074268A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2021176511 2021-10-28
JP2021-176511 2021-10-28
JP2021204856 2021-12-17
JP2021-204856 2021-12-17

Publications (1)

Publication Number Publication Date
WO2023074268A1 true WO2023074268A1 (en) 2023-05-04

Family

ID=86157861

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/036940 WO2023074268A1 (en) 2021-10-28 2022-10-03 High-strength, high-elongation polypropylene fiber and production method thereof

Country Status (1)

Country Link
WO (1) WO2023074268A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6241341A (en) * 1985-08-08 1987-02-23 東洋紡績株式会社 High speed stretching of gel fiber
JPS63323A (en) * 1986-05-05 1988-01-05 ハ−キュルス　インコ−ポレ−テッド Manufacture of radiation-resistant polypropylene-containing products
JPH06217668A (en) * 1993-01-29 1994-08-09 Mitsui Petrochem Ind Ltd Fishline made of high-strength polypropylene filament
JPH11350283A (en) * 1997-10-24 1999-12-21 Ube Nitto Kasei Co Ltd Drawing and drawn product
WO2013089175A1 (en) * 2011-12-13 2013-06-20 ダイワボウホールディングス株式会社 Fibers for cement reinforcement, method for producing same and cement hardened body
JP2018500466A (en) * 2014-12-17 2018-01-11 エテックス・サービシーズ・ナムローゼ・フエンノートシャップＥｔｅｘ Ｓｅｒｖｉｃｅｓ Ｎｖ IMPROVED POLYPROPYLENE FIBER, ITS MANUFACTURING METHOD, AND ITS USE IN PRODUCTION OF FIBER CEMENT PRODUCT
JP2019099983A (en) * 2017-12-01 2019-06-24 株式会社プライムポリマー Oriented polypropylene fiber

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6241341A (en) * 1985-08-08 1987-02-23 東洋紡績株式会社 High speed stretching of gel fiber
JPS63323A (en) * 1986-05-05 1988-01-05 ハ−キュルス　インコ−ポレ−テッド Manufacture of radiation-resistant polypropylene-containing products
JPH06217668A (en) * 1993-01-29 1994-08-09 Mitsui Petrochem Ind Ltd Fishline made of high-strength polypropylene filament
JPH11350283A (en) * 1997-10-24 1999-12-21 Ube Nitto Kasei Co Ltd Drawing and drawn product
WO2013089175A1 (en) * 2011-12-13 2013-06-20 ダイワボウホールディングス株式会社 Fibers for cement reinforcement, method for producing same and cement hardened body
JP2018500466A (en) * 2014-12-17 2018-01-11 エテックス・サービシーズ・ナムローゼ・フエンノートシャップＥｔｅｘ Ｓｅｒｖｉｃｅｓ Ｎｖ IMPROVED POLYPROPYLENE FIBER, ITS MANUFACTURING METHOD, AND ITS USE IN PRODUCTION OF FIBER CEMENT PRODUCT
JP2019099983A (en) * 2017-12-01 2019-06-24 株式会社プライムポリマー Oriented polypropylene fiber

Similar Documents

Publication Publication Date Title
EP1205586B1 (en) Multifilament yarns and methods of making
US4911165A (en) Pliabilized polypropylene surgical filaments
AU710815B2 (en) Improved process for manufacturing a polypropylene monofilament suture
US9057148B2 (en) High-strength polypropylene fiber and method for producing the same
WO1999063137A1 (en) High-strength polyethylene fiber and process for producing the same
US5443904A (en) High-tenacity polyethylene fiber
US5006296A (en) Process for the preparation of fibers of stereoregular polystyrene
WO2023074268A1 (en) High-strength, high-elongation polypropylene fiber and production method thereof
JPH01272814A (en) Polyvinyl alcohol-based yarn having excellent hot water resistance and production thereof
KR101429686B1 (en) Process for preparing high viscosity and high intensity industrial polyester fibre
JP2001172821A (en) Production of polyoxymethylene fiber
JPH1037020A (en) Production of polylactic acid-based biodegradable fiber
EP0999233A1 (en) Polypropylene/polystyrene polymer blend, improved fibers produced from the blend and method of manufacturing
JP5173271B2 (en) Method for producing high toughness fiber
JPS63165120A (en) Manufacture of high molecular substance
KR100429949B1 (en) Manufacturing Method of Polyethylene Terephthalate Fiber for Dip Cord and PET Fiber Manufactured by the Same
JPS63315608A (en) Polyester fiber
EP4190953A1 (en) Polyethylene yarn having improved post-processability, and fabric comprising same
JP2888496B2 (en) Method for producing high modulus polyvinyl alcohol fiber
JPH04343710A (en) Production of aromatic polyetherketone monofilament
KR100595602B1 (en) Polyethylene-2,6-naphthalate fibers having high tenacity and the preparation thereof
KR20040100577A (en) Method for preparing of polyester yarn having high smoothness
JPH0357965B2 (en)
KR101037123B1 (en) A technical polyester fibers with high flame retardancy
KR100457548B1 (en) Manufacturing method of anti-pilling polyester fiber with excellent leveling agent

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22886600

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2023556244

Country of ref document: JP