WO2014077402A1 - Method for producing biodegradable monofilament - Google Patents

Method for producing biodegradable monofilament Download PDF

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Publication number
WO2014077402A1
WO2014077402A1 PCT/JP2013/081111 JP2013081111W WO2014077402A1 WO 2014077402 A1 WO2014077402 A1 WO 2014077402A1 JP 2013081111 W JP2013081111 W JP 2013081111W WO 2014077402 A1 WO2014077402 A1 WO 2014077402A1
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WIPO (PCT)
Prior art keywords
resin
biodegradable
monofilament
stretching
temperature
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PCT/JP2013/081111
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French (fr)
Japanese (ja)
Inventor
紀生 尾澤
健一郎 島田
寺島　久明
明美 坪沼
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株式会社クレハ
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Priority to JP2014547067A priority Critical patent/JPWO2014077402A1/en
Publication of WO2014077402A1 publication Critical patent/WO2014077402A1/en

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/12—Stretch-spinning methods
    • D01D5/16—Stretch-spinning methods using rollers, or like mechanical devices, e.g. snubbing pins
    • 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
    • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters
    • D01F6/625—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters derived from hydroxy-carboxylic acids, e.g. lactones

Definitions

  • the present invention relates to a method for producing a biodegradable monofilament containing a polyglycolic acid resin.
  • polyamides, polyesters, polyolefins, and the like have been conventionally used as filament materials used for agricultural materials, marine products, industrial materials, and the like. Since filaments made of these resins hardly decompose in a natural environment, if they are left as they are after use, they remain semipermanently in the natural world, often causing environmental problems. For this reason, application of biodegradable resins such as polyglycolic acid resins has been studied.
  • Patent Document 1 a polyglycolic acid resin having a residual monomer amount of less than 0.5 parts by mass is melt-spun and rapidly cooled in a liquid bath at 10 ° C. or lower.
  • Patent Document 2 discloses that a polyglycolic acid resin having a residual monomer amount of 0.5 parts by mass or more is melt-spun and rapidly cooled in a refrigerant at 10 ° C. or less, and then 60 A method for producing a polyglycolic acid resin filament is disclosed, in which amorphous stretching is performed in a medium at ⁇ 83 ° C., and further, if necessary, second-stage stretching and thermal relaxation are performed. It is also described that the resulting polyglycolic acid resin filament is a biodegradable filament having high tensile strength, knot strength and moderate elongation.
  • polyglycolic acid resin filaments described in Patent Documents 1 and 2 are not necessarily high in durability against impact, and depending on the application, polyglycolic acid resin filaments with higher durability against impact are required. .
  • the present invention has been made in view of the above-described problems of the prior art, and aims to provide a method for producing a biodegradable filament containing a polyglycolic acid resin and having excellent durability against impact. To do.
  • the present inventors have performed primary stretching on an unstretched yarn obtained by melt spinning a biodegradable resin containing a polyglycolic acid resin, Furthermore, it discovered that the durability with respect to the impact of the biodegradable monofilament obtained by performing secondary extending
  • the method for producing the biodegradable monofilament of the present invention includes: A step of melt spinning a biodegradable resin containing 35% by mass or more of a polyglycolic acid resin to obtain an undrawn yarn; A step of primarily stretching the unstretched yarn in the length direction to obtain a monofilament; A step of subjecting the monofilament after the primary stretching to a lengthwise direction and a secondary stretching of 1.02 to 1.6 times at a glass transition temperature of the polyglycolic acid resin + 22 ° C. or lower; It is a method including.
  • the biodegradable resin may further contain an aliphatic-aromatic copolymer polyester.
  • the undrawn yarn is primarily drawn at a glass transition temperature of the polyglycolic acid resin + 10 ° C. or more at a temperature of 2.0 to 6.0 times.
  • the temperature during the first stretching is more preferably a glass transition temperature of the polyglycolic acid resin + 22 ° C. or higher.
  • the method for producing a biodegradable monofilament of the present invention comprises a step of spinning a biodegradable resin containing 35% by mass or more of a polyglycolic acid resin to obtain an undrawn yarn (spinning step), A step of primary stretching in the length direction to obtain a monofilament (primary stretching step), and the monofilament after the primary stretching in the length direction at a glass transition temperature of the polyglycolic acid resin + 22 ° C. or lower And a step of secondary stretching (secondary stretching step) by 1.02 to 1.6 times.
  • the PGA resin has the following formula (1): — [O—CH 2 —C ( ⁇ O)] — (1)
  • a glycolic acid homopolymer consisting only of glycolic acid repeating units represented by the formula hereinafter referred to as “PGA homopolymer”, including a ring-opened polymer of glycolide which is a bimolecular cyclic ester of glycolic acid).
  • PGA copolymer a polyglycolic acid copolymer containing glycolic acid repeating units.
  • Such PGA-type resin may be used individually by 1 type, or may use 2 or more types together.
  • the PGA homopolymer can be synthesized by dehydration polycondensation of glycolic acid, dealcoholization polycondensation of glycolic acid alkyl ester, ring-opening polymerization of glycolide, etc., among which it is preferable to synthesize by ring-opening polymerization of glycolide. .
  • Such ring-opening polymerization can be carried out by either bulk polymerization or solution polymerization.
  • the PGA copolymer can be synthesized by using a comonomer in combination in such a polycondensation reaction or ring-opening polymerization reaction.
  • comonomers include ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactides, lactones (eg, ⁇ -propiolactone, ⁇ -butyrolactone, ⁇ -pivalolactone, ⁇ - Butyrolactone, ⁇ -valerolactone, ⁇ -methyl- ⁇ -valerolactone, ⁇ -caprolactone, etc.), carbonates (eg, trimethylene carbonate, etc.), ethers (eg, 1,3-dioxane, etc.), ether esters ( For example, cyclic monomers such as dioxanone), amides (such as ⁇ -caprolactam); hydroxycarboxylic acids such as lactic acid, 3-hydroxypropanoic acid, 3-hydroxybuta
  • Catalysts used when the PGA resin is produced by ring-opening polymerization of glycolide include tin compounds such as tin halides and tin organic carboxylates; titanium compounds such as alkoxy titanates; aluminum compounds such as alkoxy aluminums Known ring-opening polymerization catalysts such as zirconium compounds such as zirconium acetylacetone; antimony compounds such as antimony halides and antimony oxides;
  • the PGA-based resin can be produced by a conventionally known polymerization method.
  • the polymerization temperature is preferably 120 to 300 ° C, more preferably 130 to 250 ° C, particularly preferably 140 to 220 ° C, and 150 to 200. C is most preferred.
  • the polymerization temperature is less than the lower limit, the polymerization tends not to proceed sufficiently.
  • the polymerization temperature exceeds the upper limit, the produced resin tends to be thermally decomposed.
  • the polymerization time of the PGA resin is preferably 2 minutes to 50 hours, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 18 hours.
  • the polymerization time is less than the lower limit, the polymerization does not proceed sufficiently, whereas when the upper limit is exceeded, the generated resin tends to be colored.
  • the content of the glycolic acid repeating unit represented by the formula (1) is preferably 55% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more. 90 mass% or more is particularly preferable, and 100 mass% is most preferable.
  • the effects as a PGA resin such as biodegradability, hydrolyzability, biocompatibility, mechanical strength, and heat resistance tend to be reduced.
  • the weight average molecular weight of such a PGA resin is preferably 30,000 to 800,000, more preferably 50,000 to 500,000, and particularly preferably 80,000 to 300,000.
  • the weight average molecular weight of the PGA resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease.
  • the upper limit is exceeded, the molten PGA resin may be discharged. It tends to be difficult.
  • the weight average molecular weight is a polymethylmethacrylate conversion value measured by gel permeation chromatography (GPC).
  • the melt viscosity (temperature: 240 ° C., shear rate: 122 sec-1) of the PGA resin is preferably 1 to 10,000 Pa ⁇ s, more preferably 50 to 6000 Pa ⁇ s, and still more preferably 100 to 5000 Pa ⁇ s. 300 to 4000 Pa ⁇ s is particularly preferable. If the melt viscosity is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to be reduced. On the other hand, if the melt viscosity exceeds the upper limit, it tends to be difficult to discharge the molten PGA resin. .
  • the glass transition temperature Tg of the PGA resin is preferably 30 to 50 ° C., more preferably 35 to 45 ° C.
  • the glass transition temperature Tg (unit: ° C.) of the PGA resin was obtained by heating the PGA resin from 0 ° C. to 270 ° C. at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter. It is obtained from the DSC curve.
  • the PGA resin may be used alone or in combination with other biodegradable resins.
  • the durability of the resulting biodegradable monofilament with respect to impact tends to be improved.
  • biodegradable resins examples include polyhydroxyalkanoic acid esters other than PGA resins (eg, polyhydroxybutyrate (PHB resin), polymalic acid, polyhydroxyvalerate, poly- ⁇ -caprolactone (PCL resin).
  • PHB resin polyhydroxybutyrate
  • PCL resin poly- ⁇ -caprolactone
  • Polyether esters eg, polydioxanone
  • copolymers of aliphatic dicarboxylic acids and aliphatic diols eg, polybutylene succinate (PBS resin), polyethylene succinate (PES resin), polyethylene adipate (PEA resin)
  • PBS resin polybutylene succinate
  • PES resin polyethylene succinate
  • PET resin polyethylene adipate
  • PBAT resin polybutylene adipate-butylene tele Tareto copolymer
  • PBST resin polybutylene succinate - aliphatic such butylene terephthalate coater rates copolymer (PBST resin) - such as aromatic copolymerized polyester.
  • biodegradable resins may be used alone or in combination of two or more.
  • aliphatic-aromatic copolyesters are preferred, and PBAT resins are more preferred from the viewpoint of improving the durability against impact of the resulting biodegradable monofilament.
  • the weight average molecular weight of such other biodegradable resins is preferably 10,000 to 800,000, more preferably 20,000 to 600,000, and particularly preferably 40,000 to 400,000.
  • the weight average molecular weight of the other biodegradable resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease, whereas when the upper limit is exceeded, the biodegradable resin in the molten state is reduced. It tends to be difficult to discharge.
  • the weight average molecular weight is a polymethylmethacrylate conversion value measured by gel permeation chromatography (GPC).
  • the melt viscosity (temperature: 200 ° C., shear rate: 122 sec-1) of other biodegradable resins is preferably 1 to 10,000 Pa ⁇ s, more preferably 10 to 6000 Pa ⁇ s, and more preferably 50 to 4000 Pa ⁇ s. More preferred is 100 to 2000 Pa ⁇ s. If the melt viscosity is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease, whereas if the upper limit is exceeded, it tends to be difficult to discharge the melted biodegradable resin. is there.
  • the biodegradable resin used in the present invention contains 35% by mass or more of PGA resin.
  • PGA resin may consist of 100% by mass of PGA-based resin, 35% by mass to less than 100% by mass of PGA-based resin, and more than 0% by mass and 65% by mass or less of the other resins. And a mixture thereof.
  • the content of the PGA resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament is lowered.
  • biodegradable resin according to the present invention containing 35% by mass or more of PGA-based resin
  • the biodegradable resin according to the present invention can be added to the biodegradable resin according to the present invention within the range not impairing the object of the present invention.
  • Thermoplastic resins and various additives for example, plasticizers, heat stabilizers, light stabilizers, moisture proofing agents, waterproofing agents, water repellents, lubricants, mold release agents, coupling agents, oxygen absorbers, pigments, dyes
  • the manufacturing method of the biodegradable monofilament of this invention is demonstrated.
  • the biodegradable monofilament manufacturing method of the present invention is a method including a spinning step, a primary stretching step, and a secondary stretching step.
  • a spinning step a spinning step
  • a primary stretching step a primary stretching step
  • a secondary stretching step a secondary stretching step
  • a biodegradable resin containing 35% by mass or more of a PGA-based resin is melted (preferably melt-kneaded) using an extruder or the like.
  • the melting temperature is preferably 200 to 300 ° C, more preferably 230 to 280 ° C, and particularly preferably 240 to 270 ° C.
  • the melting temperature is less than the lower limit, the fluidity of the biodegradable resin according to the present invention is reduced, the biodegradable resin is not discharged from the nozzle, and it tends to be difficult to mold the biodegradable resin monofilament,
  • the upper limit is exceeded, the biodegradable resin according to the present invention tends to be colored or thermally decomposed.
  • Such a melting process can be performed using an agitator or a continuous kneader in addition to the extruder, but the process can be performed in a short time and a smooth transition to the subsequent discharge process is possible. From the viewpoint of being, it is preferable to use an extruder.
  • the biodegradable resin according to the present invention thus melted is discharged from a single-layer nozzle, and then cooled (preferably quenched in a liquid bath at 10 ° C. or lower, more preferably 5 ° C. or lower).
  • An undrawn yarn is obtained by taking it up with a roller or the like.
  • the temperature of the single layer nozzle is preferably 210 to 280 ° C, more preferably 230 to 270 ° C, and particularly preferably 240 to 260 ° C.
  • the fluidity of the biodegradable resin according to the present invention is lowered, the biodegradable resin is not discharged from the nozzle, and the biodegradable resin monofilament tends to be difficult to mold.
  • the upper limit is exceeded, the biodegradable resin according to the present invention tends to be thermally decomposed.
  • the pore diameter of the single-layer nozzle is appropriately selected according to the intended use of the resulting biodegradable monofilament, and is not particularly limited, but is preferably 2 to 15 mm ⁇ , and more preferably 4 to 10 mm ⁇ .
  • the undrawn yarn obtained in the spinning step is primarily drawn in the length direction (take-off direction) to obtain a monofilament.
  • a biodegradable monofilament excellent in mechanical strength can be obtained.
  • the primary stretching temperature T 1 is preferably Tg + 10 ° C. or higher of the PGA resin, that is, T 1 ⁇ Tg + 10 ° C., assuming that the glass transition temperature of the PGA resin is Tg, It is more preferable to satisfy T 1 ⁇ Tg + 15 ° C., and it is particularly preferable to satisfy T 1 ⁇ Tg + 22 ° C.
  • T 1 ⁇ Tg + 40 °C the primary stretching temperature
  • the glass transition temperature Tg (unit: ° C.) of the PGA resin is such that the PGA resin is heated from 0 ° C. to 270 ° C. at a heating rate of 20 ° C./min using a differential scanning calorimeter. It is obtained from the obtained DSC curve.
  • the primary draw ratio is preferably 2.0 to 6.0 times. If the primary draw ratio is less than the lower limit, the mechanical strength of the biodegradable monofilament finally obtained tends to be low. On the other hand, if the upper limit is exceeded, the secondary draw becomes difficult and finally obtained. The biodegradable monofilaments that are produced tend to be less durable against impact.
  • a desired biodegradable monofilament can be obtained by secondary-stretching the monofilament subjected to primary stretching in this way in the length direction (take-off direction) under predetermined conditions.
  • secondary stretching a biodegradable monofilament excellent in durability against impact can be obtained.
  • the secondary stretching temperature T 2 is preferably a temperature of Tg + 22 ° C. or lower of the PGA-based resin, that is, satisfies T 2 ⁇ Tg + 22 ° C.
  • the secondary stretching temperature T 2 preferably satisfies T 2 ⁇ Tg + 20 ° C., more preferably satisfies T 2 ⁇ Tg + 15 ° C., and T 2 ⁇ It is more preferable that Tg + 10 ° C. is satisfied, T 2 ⁇ Tg + 5 ° C.
  • T 2 ⁇ Tg is more preferable, T 2 ⁇ Tg is further more preferable, T 2 ⁇ Tg ⁇ 5 ° C. is particularly preferable, and T 2 ⁇ Most preferably, Tg ⁇ 10 ° C. is satisfied.
  • the lower limit of the secondary stretching temperature preferably satisfies T 2 ⁇ Tg ⁇ 20 ° C. When the secondary stretching temperature is less than the lower limit, secondary stretching becomes difficult, and the durability of the biodegradable monofilament finally obtained tends to be low.
  • the secondary drawing is be carried out in the primary stretching temperature T 1 of the following temperatures, i.e., secondary stretching temperature T 2 preferably satisfies the T 2 ⁇ T 1.
  • the secondary stretching temperature preferably satisfies T 2 ⁇ T 1 ⁇ 5 ° C., more preferably satisfies T 2 ⁇ T 1 ⁇ 10 ° C., and satisfies T 2 ⁇ T 1 ⁇ 15 ° C. Is more preferable, T 2 ⁇ T 1 ⁇ 20 ° C. is more preferable, T 2 ⁇ T 1 ⁇ 25 ° C. is more preferable, and T 2 ⁇ T 1 ⁇ 30 ° C. is most preferable. preferable.
  • the temperature is usually higher than the temperature during the primary stretching (that is, T 2 > T 1 ).
  • the secondary stretching is performed.
  • the secondary stretching is performed at a temperature equal to or lower than the temperature during the primary stretching, thereby ensuring excellent durability against the impact of the obtained monofilament.
  • the secondary stretching ratio is 1.02 to 1.6 times.
  • the durability of the biodegradable monofilament finally obtained is not improved compared to the case where the secondary stretching is not performed, and when the upper limit is exceeded, The monofilament breaks.
  • the biodegradable monofilament thus obtained has not only excellent mechanical strength but also excellent durability against impact. Therefore, the biodegradable monofilament produced by the method of the present invention can be used for applications that require durability against impacts, such as mowing cords for brush cutters.
  • the effect of secondary stretching according to the present invention does not depend on the thickness of the biodegradable monofilament. Therefore, in the present invention, the diameter of the obtained biodegradable monofilament can be appropriately selected depending on the application. For example, when used as a mowing cord of a brush cutter, 1.4 to 3 mm is preferable.
  • the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.
  • the glass transition temperature of PGA-type resin was measured with the following method.
  • Example 1 Pellet PGA resin (manufactured by Kureha Co., Ltd., glass transition temperature: 38 ° C., weight average molecular weight: 190,000, melt viscosity (temperature 270 ° C., shear rate 122 sec-1): 350 Pa ⁇ s, melting point: 220 ° C.)
  • the raw material hopper was charged into a single screw extruder with a cylinder diameter of 35 mm ⁇ and melted at 230 to 250 ° C.
  • the cylinder temperature of the extruder was set to 230 to 250 ° C., and the adapter temperature and gear pump temperature were both set to 250 ° C.
  • the molten PGA resin was discharged at 110 g / min from a single-layer nozzle (hole diameter 8 mm ⁇ ) set at 250 ° C. using a gear pump, and was taken out at a take-up speed of 4 m / min while rapidly cooling in a 5 ° C. water bath. Thereafter, the obtained unstretched PGA resin yarn was primarily stretched in the take-off direction (length direction) at a draw ratio of 4.0 times while being heated in a 60 ° C. (Pg resin Tg + 22 ° C.) hot water bath. The monofilament was further stretched at 23 ° C. (PGA resin Tg ⁇ 15 ° C.) in the take-up direction (length direction) at a draw ratio of 1.2 times to obtain a biodegradable monofilament having a diameter of 2.3 mm.
  • Example 2 A biodegradable monofilament having a diameter of 2.3 mm was prepared in the same manner as in Example 1 except that the monofilament after the primary stretching was heat-treated at 150 ° C. in a dry heat bath and then subjected to the secondary stretching. Durability was evaluated. The results are shown in Table 1.
  • Example 3 A biodegradable monofilament having a diameter of 2.4 mm or 2.2 mm was produced in the same manner as in Example 2 except that the secondary draw ratio was changed to 1.02 times or 1.5 times, and durability against impact was evaluated. did. The results are shown in Table 1.
  • Example 6 A biodegradable monofilament having a diameter of 2.3 mm was produced in the same manner as in Example 2 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 1.
  • Example 7 A biodegradable monofilament having a diameter of 2.4 mm was produced in the same manner as in Example 2 except that the primary draw ratio was changed to 3.0, and durability against impact was evaluated. The results are shown in Table 1.
  • Example 8 Pellet PGA resin (manufactured by Kureha Co., Ltd., glass transition temperature: 38 ° C., weight average molecular weight: 190,000, melt viscosity (temperature: 270 ° C., shear rate: 122 sec-1): 350 Pa ⁇ s, melting point: 220 ° C.) 50 Part by mass and polybutylene adipate-butylene terephthalate copolymer ("Ecoflex FBELND C1200" manufactured by BASF, glass transition temperature: -30 ° C, weight average molecular weight: 74000, melt viscosity (temperature 200 ° C, shear rate 122 sec-1 ): 240 Pa ⁇ s, melting point: 115 ° C.
  • PBAT resin 50 parts by mass, and 0.3 parts by mass of xylene diisocyanate (Mitsui) with respect to 100 parts by mass of the obtained mixture.
  • Chemical "Takenate 500" was added as a reactive compatibilizer.
  • TEM-26SS twin-screw kneading extruder
  • a biodegradable monofilament having a diameter of 2.3 mm was prepared in the same manner as in Example 1 except that this pellet-like PGA-PBAT resin composition was used in place of the PGA resin, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 9 A biodegradability of 2.4 mm in diameter was performed in the same manner as in Example 8 except that the monofilament after primary stretching was heat-treated at 150 ° C. in a dry heat bath and then subjected to secondary stretching at a stretching ratio of 1.1 times. Monofilaments were prepared and evaluated for durability against impact. The results are shown in Table 2.
  • Example 10 A biodegradable monofilament having a diameter of 2.2 mm was produced in the same manner as in Example 9 except that the secondary draw ratio was changed to 1.5, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 11 A biodegradable monofilament having a diameter of 2.5 mm was produced in the same manner as in Example 9 except that the primary draw ratio was changed to 3.0, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 12 A biodegradable monofilament having a diameter of 2.4 mm or 2.3 mm was produced in the same manner as in Example 11 except that the secondary draw ratio was changed to 1.2 times or 1.5 times, and durability against impact was evaluated. did. The results are shown in Table 2.
  • Example 14 to 15 A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 2.
  • Example 16 A biodegradable monofilament having a diameter of 2.4 mm was prepared in the same manner as in Example 12 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 2.
  • Example 18 A biodegradable monofilament having a diameter of 2.4 mm or 2.5 mm was produced in the same manner as in Example 9 or 11 except that the temperature of primary stretching was changed to 75 ° C. (Tg of PGA resin + 37 ° C.), and durability against impacts Sex was evaluated. The results are shown in Table 2.
  • Example 20 A biodegradable monofilament having a diameter of 2.5 mm was produced in the same manner as in Example 11 except that 40 parts by mass of PGA resin and 60 parts by mass of PBAT resin were mixed, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 21 A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that 60 parts by mass of PGA resin and 40 parts by mass of PBAT resin were mixed, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 6 A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 9 except that secondary stretching was not performed, and durability against impact was evaluated. The results are shown in Table 2.
  • Example 7 A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that only the PBAT resin was used instead of the PGA-PBAT resin composition, and the durability against impact was evaluated. The results are shown in Table 2.
  • monofilaments subjected only to primary stretching are biodegradable monofilaments of the present invention (Examples 1 to 7 and Examples 8 to 8) further subjected to predetermined secondary stretching. Compared to 9), the durability against impact was inferior.
  • monofilaments (Comparative Examples 3 to 5) subjected to secondary stretching at a temperature exceeding a predetermined temperature (which is also a temperature exceeding the temperature during primary stretching) have a predetermined temperature (below the temperature during primary stretching).
  • the biodegradable monofilaments of the present invention Examples 1 to 2, 5 to 6) subjected to secondary stretching in the above-described manner.
  • the monofilament not containing the PGA resin (Comparative Example 7) was compared with the biodegradable monofilament of the present invention containing the PGA resin (Examples 11 and 20 to 21). The durability against impact was inferior.
  • the method for producing a biodegradable filament of the present invention is useful as a monofilament used for applications requiring biodegradability and durability against impact, for example, a mowing cord for a brush cutter in place of a nylon cord.

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Abstract

A method for producing a biodegradable monofilament, which is characterized by comprising: a step for obtaining an undrawn yarn by melt spinning a biodegradable resin that contains 35% by mass or more of a polyglycolic acid resin; a step for obtaining a monofilament by primarily drawing the undrawn yarn in the length direction; and a step for secondarily drawing the primarily drawn monofilament 1.02-1.6 times in the length direction at a temperature that is higher than the glass transition temperature of the polyglycolic acid resin by 22°C or less.

Description

生分解性モノフィラメントの製造方法Method for producing biodegradable monofilament
　本発明は、ポリグリコール酸系樹脂を含有する生分解性モノフィラメントの製造方法に関する。 The present invention relates to a method for producing a biodegradable monofilament containing a polyglycolic acid resin.
　農業資材、水産資材、工業資材などに使用されるフィラメント用原料としては、要求される力学特性の観点から、従来は、ポリアミド、ポリエステル、ポリオレフィンなどが用いられてきた。これらの樹脂からなるフィラメントは、自然環境下ではほとんど分解しないため、使用後にそのまま放置されると、半永久的に自然界に残存することとなり、しばしば環境問題の原因となっていた。このため、ポリグリコール酸系樹脂などの生分解性樹脂の適用が検討されてきた。 From the viewpoint of required mechanical properties, polyamides, polyesters, polyolefins, and the like have been conventionally used as filament materials used for agricultural materials, marine products, industrial materials, and the like. Since filaments made of these resins hardly decompose in a natural environment, if they are left as they are after use, they remain semipermanently in the natural world, often causing environmental problems. For this reason, application of biodegradable resins such as polyglycolic acid resins has been studied.
　しかしながら、生分解性に優れた樹脂は、一般的には、力学特性に劣る傾向にあり、生分解性と力学特性をバランスよく備えるフィラメントが求められてきた。そこで、国際公開第２００５／０９０６５７号（特許文献１）には、残留モノマー量が０．５質量部未満のポリグリコール酸系樹脂を溶融紡糸し、１０℃以下の液浴中で急冷した後、６０～８３℃の液浴中で第１段目の延伸を行い、必要に応じてさらに、好ましくは第１段目の延伸温度より高い温度で第２段目の延伸を行う、ポリグリコール酸系樹脂フィラメントの製造方法が開示されており、この方法により得られるポリグリコール酸系樹脂フィラメントが高い引張強度および結節強度を有する生分解性フィラメントであることも記載されている。また、特開２００７－７７５５８号公報（特許文献２）には、残留モノマー量が０．５質量部以上のポリグリコール酸系樹脂を溶融紡糸し、１０℃以下の冷媒中で急冷した後、６０～８３℃の媒体中で非晶延伸を行い、必要に応じてさらに、第２段目の延伸と熱緩和を行う、ポリグリコール酸系樹脂フィラメントの製造方法が開示されており、この方法により得られるポリグリコール酸系樹脂フィラメントが高い引張強度および結節強度と適度な伸度を有する生分解性フィラメントであることも記載されている。 However, resins excellent in biodegradability generally tend to be inferior in mechanical properties, and filaments having a good balance between biodegradability and mechanical properties have been demanded. Therefore, in International Publication No. 2005/090657 (Patent Document 1), a polyglycolic acid resin having a residual monomer amount of less than 0.5 parts by mass is melt-spun and rapidly cooled in a liquid bath at 10 ° C. or lower. A polyglycolic acid system in which the first stage stretching is performed in a liquid bath at 60 to 83 ° C., and if necessary, the second stage stretching is preferably performed at a temperature higher than the first stage stretching temperature. A method for producing a resin filament is disclosed, and it is also described that a polyglycolic acid resin filament obtained by this method is a biodegradable filament having high tensile strength and knot strength. Japanese Patent Application Laid-Open No. 2007-77558 (Patent Document 2) discloses that a polyglycolic acid resin having a residual monomer amount of 0.5 parts by mass or more is melt-spun and rapidly cooled in a refrigerant at 10 ° C. or less, and then 60 A method for producing a polyglycolic acid resin filament is disclosed, in which amorphous stretching is performed in a medium at ˜83 ° C., and further, if necessary, second-stage stretching and thermal relaxation are performed. It is also described that the resulting polyglycolic acid resin filament is a biodegradable filament having high tensile strength, knot strength and moderate elongation.
国際公開第２００５／０９０６５７号International Publication No. 2005/090657 特開２００７－７７５５８号公報JP 2007-77558 A
　しかしながら、特許文献１～２に記載のポリグリコール酸系樹脂フィラメントは、衝撃に対する耐久性が必ずしも高いものではなく、用途によっては衝撃に対する耐久性がさらに高いポリグリコール酸系樹脂フィラメントが求められている。 However, the polyglycolic acid resin filaments described in Patent Documents 1 and 2 are not necessarily high in durability against impact, and depending on the application, polyglycolic acid resin filaments with higher durability against impact are required. .
　本発明は、上記従来技術の有する課題に鑑みてなされたものであり、ポリグリコール酸系樹脂を含有し、衝撃に対する耐久性に優れた生分解性フィラメントを製造する方法を提供することを目的とする。 The present invention has been made in view of the above-described problems of the prior art, and aims to provide a method for producing a biodegradable filament containing a polyglycolic acid resin and having excellent durability against impact. To do.
　本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、ポリグリコール酸系樹脂を含有する生分解性樹脂を溶融紡糸して得られる未延伸糸に１次延伸を施した後、さらに、所定の温度で２次延伸を施すことによって、得られる生分解性モノフィラメントの衝撃に対する耐久性が向上することを見出し、本発明を完成するに至った。 As a result of intensive studies to achieve the above object, the present inventors have performed primary stretching on an unstretched yarn obtained by melt spinning a biodegradable resin containing a polyglycolic acid resin, Furthermore, it discovered that the durability with respect to the impact of the biodegradable monofilament obtained by performing secondary extending | stretching by predetermined | prescribed temperature improved, and came to complete this invention.
　すなわち、本発明の生分解性モノフィラメントの製造方法は、
ポリグリコール酸系樹脂を３５質量％以上含有する生分解性樹脂を溶融紡糸して未延伸糸を得る工程と、
前記未延伸糸を長さ方向に１次延伸してモノフィラメントを得る工程と、
前記１次延伸後のモノフィラメントを長さ方向に、前記ポリグリコール酸系樹脂のガラス転移温度＋２２℃以下の温度で１．０２～１．６倍に２次延伸する工程と、
を含む方法である。また、前記生分解性樹脂には、脂肪族－芳香族共重合ポリエステルが更に含まれていてもよい。 That is, the method for producing the biodegradable monofilament of the present invention includes:
A step of melt spinning a biodegradable resin containing 35% by mass or more of a polyglycolic acid resin to obtain an undrawn yarn;
A step of primarily stretching the unstretched yarn in the length direction to obtain a monofilament;
A step of subjecting the monofilament after the primary stretching to a lengthwise direction and a secondary stretching of 1.02 to 1.6 times at a glass transition temperature of the polyglycolic acid resin + 22 ° C. or lower;
It is a method including. The biodegradable resin may further contain an aliphatic-aromatic copolymer polyester.
　本発明の生分解性モノフィラメントの製造方法においては、前記未延伸糸を前記ポリグリコール酸系樹脂のガラス転移温度＋１０℃以上の温度で２．０～６．０倍に１次延伸することが好ましく、前記１次延伸時の温度が前記ポリグリコール酸系樹脂のガラス転移温度＋２２℃以上の温度であることがより好ましい。また、前記１次延伸時の温度以下の温度で２次延伸することが好ましい。 In the method for producing a biodegradable monofilament of the present invention, it is preferable that the undrawn yarn is primarily drawn at a glass transition temperature of the polyglycolic acid resin + 10 ° C. or more at a temperature of 2.0 to 6.0 times. The temperature during the first stretching is more preferably a glass transition temperature of the polyglycolic acid resin + 22 ° C. or higher. Further, it is preferable to perform secondary stretching at a temperature equal to or lower than the temperature during the primary stretching.
　本発明によれば、ポリグリコール酸系樹脂を含有し、衝撃に対する耐久性に優れた生分解性フィラメントを得ることが可能となる。 According to the present invention, it is possible to obtain a biodegradable filament containing a polyglycolic acid resin and having excellent durability against impact.
　以下、本発明をその好適な実施形態に即して詳細に説明する。 Hereinafter, the present invention will be described in detail on the basis of preferred embodiments thereof.
　本発明の生分解性モノフィラメントの製造方法は、ポリグリコール酸系樹脂を３５質量％以上含有する生分解性樹脂を溶融紡糸して未延伸糸を得る工程（紡糸工程）と、前記未延伸糸を長さ方向に１次延伸してモノフィラメントを得る工程（１次延伸工程）と、前記１次延伸後のモノフィラメントを長さ方向に、前記ポリグリコール酸系樹脂のガラス転移温度＋２２℃以下の温度で１．０２～１．６倍に２次延伸する工程（２次延伸工程）と、を含む方法である。 The method for producing a biodegradable monofilament of the present invention comprises a step of spinning a biodegradable resin containing 35% by mass or more of a polyglycolic acid resin to obtain an undrawn yarn (spinning step), A step of primary stretching in the length direction to obtain a monofilament (primary stretching step), and the monofilament after the primary stretching in the length direction at a glass transition temperature of the polyglycolic acid resin + 22 ° C. or lower And a step of secondary stretching (secondary stretching step) by 1.02 to 1.6 times.
　（ポリグリコール酸系樹脂）
　先ず、本発明に用いるポリグリコール酸系樹脂（以下、「ＰＧＡ系樹脂」という。）について説明する。前記ＰＧＡ系樹脂は、下記式（１）：
－［Ｏ－ＣＨ２－Ｃ（＝Ｏ）］－　　　　　（１）
で表されるグリコール酸繰り返し単位のみからなるグリコール酸の単独重合体（以下、「ＰＧＡ単独重合体」という。グリコール酸の２分子間環状エステルであるグリコリドの開環重合体を含む。）、前記グリコール酸繰り返し単位を含むポリグリコール酸共重合体（以下、「ＰＧＡ共重合体」という。）などが挙げられる。このようなＰＧＡ系樹脂は、１種を単独で使用しても２種以上を併用してもよい。 (Polyglycolic acid resin)
First, the polyglycolic acid resin (hereinafter referred to as “PGA resin”) used in the present invention will be described. The PGA resin has the following formula (1):
— [O—CH 2 —C (═O)] — (1)
A glycolic acid homopolymer consisting only of glycolic acid repeating units represented by the formula (hereinafter referred to as “PGA homopolymer”, including a ring-opened polymer of glycolide which is a bimolecular cyclic ester of glycolic acid). And a polyglycolic acid copolymer containing glycolic acid repeating units (hereinafter referred to as “PGA copolymer”). Such PGA-type resin may be used individually by 1 type, or may use 2 or more types together.
　前記ＰＧＡ単独重合体は、グリコール酸の脱水重縮合、グリコール酸アルキルエステルの脱アルコール重縮合、グリコリドの開環重合などにより合成することができ、中でも、グリコリドの開環重合により合成することが好ましい。なお、このような開環重合は塊状重合および溶液重合のいずれでも行うことができる。 The PGA homopolymer can be synthesized by dehydration polycondensation of glycolic acid, dealcoholization polycondensation of glycolic acid alkyl ester, ring-opening polymerization of glycolide, etc., among which it is preferable to synthesize by ring-opening polymerization of glycolide. . Such ring-opening polymerization can be carried out by either bulk polymerization or solution polymerization.
　また、前記ＰＧＡ共重合体は、このような重縮合反応や開環重合反応においてコモノマーを併用することによって合成することができる。このようなコモノマーとしては、シュウ酸エチレン（すなわち、１，４－ジオキサン－２，３－ジオン）、ラクチド類、ラクトン類（例えば、β－プロピオラクトン、β－ブチロラクトン、β－ピバロラクトン、γ－ブチロラクトン、δ－バレロラクトン、β－メチル－δ－バレロラクトン、ε－カプロラクトンなど）、カーボネート類（例えば、トリメチレンカーボネートなど）、エーテル類（例えば、１，３－ジオキサンなど）、エーテルエステル類（例えば、ジオキサノンなど）、アミド類（ε－カプロラクタムなど）などの環状モノマー；乳酸、３－ヒドロキシプロパン酸、３－ヒドロキシブタン酸、４－ヒドロキシブタン酸、６－ヒドロキシカプロン酸などのヒドロキシカルボン酸またはそのアルキルエステル；エチレングリコール、１，４－ブタンジオールなどの脂肪族ジオール類と、こはく酸、アジピン酸などの脂肪族ジカルボン酸類またはそのアルキルエステル類との実質的に等モルの混合物を挙げることができる。これらのコモノマーは１種を単独で使用しても２種以上を併用してもよい。 Further, the PGA copolymer can be synthesized by using a comonomer in combination in such a polycondensation reaction or ring-opening polymerization reaction. Such comonomers include ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactides, lactones (eg, β-propiolactone, β-butyrolactone, β-pivalolactone, γ- Butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (eg, trimethylene carbonate, etc.), ethers (eg, 1,3-dioxane, etc.), ether esters ( For example, cyclic monomers such as dioxanone), amides (such as ε-caprolactam); hydroxycarboxylic acids such as lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxycaproic acid, or Its alkyl ester; ethylene glycol, 1 Aliphatic diols such as 1,4-butanediol, succinic acid, and substantially equimolar mixture of an aliphatic dicarboxylic acid or its alkyl esters such as adipic acid. These comonomers may be used individually by 1 type, or may use 2 or more types together.
　前記ＰＧＡ系樹脂をグリコリドの開環重合によって製造する場合に使用する触媒としては、ハロゲン化スズ、有機カルボン酸スズなどのスズ系化合物；アルコキシチタネートなどのチタン系化合物；アルコキシアルミニウムなどのアルミニウム系化合物；ジルコニウムアセチルアセトンなどのジルコニウム系化合物；ハロゲン化アンチモン、酸化アンチモンなどのアンチモン系化合物といった公知の開環重合触媒が挙げられる。 Catalysts used when the PGA resin is produced by ring-opening polymerization of glycolide include tin compounds such as tin halides and tin organic carboxylates; titanium compounds such as alkoxy titanates; aluminum compounds such as alkoxy aluminums Known ring-opening polymerization catalysts such as zirconium compounds such as zirconium acetylacetone; antimony compounds such as antimony halides and antimony oxides;
　前記ＰＧＡ系樹脂は従来公知の重合方法により製造することができるが、その重合温度としては、１２０～３００℃が好ましく、１３０～２５０℃がより好ましく、１４０～２２０℃が特に好ましく、１５０～２００℃が最も好ましい。重合温度が前記下限未満になると重合が十分に進行しない傾向にあり、他方、前記上限を超えると生成した樹脂が熱分解する傾向にある。 The PGA-based resin can be produced by a conventionally known polymerization method. The polymerization temperature is preferably 120 to 300 ° C, more preferably 130 to 250 ° C, particularly preferably 140 to 220 ° C, and 150 to 200. C is most preferred. When the polymerization temperature is less than the lower limit, the polymerization tends not to proceed sufficiently. On the other hand, when the polymerization temperature exceeds the upper limit, the produced resin tends to be thermally decomposed.
　また、前記ＰＧＡ系樹脂の重合時間としては、２分間～５０時間が好ましく、３分間～３０時間がより好ましく、５分間～１８時間が特に好ましい。重合時間が前記下限未満になると重合が十分に進行しない傾向にあり、他方、前記上限を超えると生成した樹脂が着色する傾向にある。 The polymerization time of the PGA resin is preferably 2 minutes to 50 hours, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 18 hours. When the polymerization time is less than the lower limit, the polymerization does not proceed sufficiently, whereas when the upper limit is exceeded, the generated resin tends to be colored.
　本発明に用いるＰＧＡ系樹脂において、前記式（１）で表されるグリコール酸繰り返し単位の含有量としては、５５質量％以上が好ましく、７０質量％以上がより好ましく、８０質量％以上がさらに好ましく、９０質量％以上が特に好ましく、１００質量％が最も好ましい。グリコール酸繰り返し単位の含有量が前記下限未満になると、生分解性や加水分解性、生体適合性、機械的強度、耐熱性といったＰＧＡ系樹脂としての効果が低下する傾向にある。 In the PGA resin used in the present invention, the content of the glycolic acid repeating unit represented by the formula (1) is preferably 55% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more. 90 mass% or more is particularly preferable, and 100 mass% is most preferable. When the content of the glycolic acid repeating unit is less than the lower limit, the effects as a PGA resin such as biodegradability, hydrolyzability, biocompatibility, mechanical strength, and heat resistance tend to be reduced.
　このようなＰＧＡ系樹脂の重量平均分子量としては、３万～８０万が好ましく、５万～５０万がより好ましく、８万～３０万が特に好ましい。ＰＧＡ系樹脂の重量平均分子量が前記下限未満になると、得られる生分解性モノフィラメントの機械的強度が低下する傾向にあり、他方、前記上限を超えると、溶融状態のＰＧＡ系樹脂を吐出させることが困難となる傾向にある。なお、前記重量平均分子量はゲルパーミエーションクロマトグラフィ（ＧＰＣ）により測定したポリメチルメタクリレート換算値である。 The weight average molecular weight of such a PGA resin is preferably 30,000 to 800,000, more preferably 50,000 to 500,000, and particularly preferably 80,000 to 300,000. When the weight average molecular weight of the PGA resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease. On the other hand, when the upper limit is exceeded, the molten PGA resin may be discharged. It tends to be difficult. The weight average molecular weight is a polymethylmethacrylate conversion value measured by gel permeation chromatography (GPC).
　また、前記ＰＧＡ系樹脂の溶融粘度（温度：２４０℃、剪断速度：１２２ｓｅｃ－１）としては、１～１００００Ｐａ・ｓが好ましく、５０～６０００Ｐａ・ｓがより好ましく、１００～５０００Ｐａ・ｓがさらに好ましく、３００～４０００Ｐａ・ｓが特に好ましい。溶融粘度が前記下限未満になると、得られる生分解性モノフィラメントの機械的強度が低下する傾向にあり、他方、前記上限を超えると溶融状態のＰＧＡ系樹脂を吐出させることが困難となる傾向にある。 The melt viscosity (temperature: 240 ° C., shear rate: 122 sec-1) of the PGA resin is preferably 1 to 10,000 Pa · s, more preferably 50 to 6000 Pa · s, and still more preferably 100 to 5000 Pa · s. 300 to 4000 Pa · s is particularly preferable. If the melt viscosity is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to be reduced. On the other hand, if the melt viscosity exceeds the upper limit, it tends to be difficult to discharge the molten PGA resin. .
　さらに、前記ＰＧＡ系樹脂のガラス転移温度Ｔｇとしては、３０～５０℃が好ましく、３５～４５℃がより好ましい。なお、前記ＰＧＡ系樹脂のガラス転移温度Ｔｇ（単位：℃）は、ＰＧＡ系樹脂を示差走査熱量測定装置を用いて０℃から２７０℃まで昇温速度２０℃／分で加熱し、得られたＤＳＣ曲線から求められるものである。 Furthermore, the glass transition temperature Tg of the PGA resin is preferably 30 to 50 ° C., more preferably 35 to 45 ° C. The glass transition temperature Tg (unit: ° C.) of the PGA resin was obtained by heating the PGA resin from 0 ° C. to 270 ° C. at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter. It is obtained from the DSC curve.
　（その他の生分解性樹脂）
　本発明においては、前記ＰＧＡ系樹脂を単独で使用してもよいが、その他の生分解性樹脂と併用してもよい。ＰＧＡ系樹脂とその他の生分解樹脂とを併用することによって、得られる生分解性モノフィラメントの衝撃に対する耐久性が向上する傾向にある。 (Other biodegradable resins)
In the present invention, the PGA resin may be used alone or in combination with other biodegradable resins. By using the PGA resin and other biodegradable resins in combination, the durability of the resulting biodegradable monofilament with respect to impact tends to be improved.
　このようなその他の生分解性樹脂としては、ＰＧＡ系樹脂以外のポリヒドロキシアルカン酸エステル（例えば、ポリヒドロキシブチレート（ＰＨＢ樹脂）、ポリリンゴ酸、ポリヒドロキシバリレート、ポリ－ε－カプロラクトン（ＰＣＬ樹脂））、ポリエーテルエステル（例えば、ポリジオキサノン）、脂肪族ジカルボン酸と脂肪族ジオールとの共重合体（例えば、ポリブチレンサクシネート（ＰＢＳ樹脂）、ポリエチレンサクシネート（ＰＥＳ樹脂）、ポリエチレンアジペート（ＰＥＡ樹脂））、脂肪族ポリカーボネート（例えば、ポリトリメチレンカーボネート）、脂肪族ポリエステルカーボネート（例えば、ポリエステルポリウレタン、ポリエーテルウレタン）といった脂肪族ポリエステル；ポリブチレンアジペート－ブチレンテレフターレート共重合体（ＰＢＡＴ樹脂）、ポリブチレンサクシネート－ブチレンテレフターレート共重合体（ＰＢＳＴ樹脂）といった脂肪族－芳香族共重合ポリエステルなどが挙げられる。これらの生分解性樹脂は、１種を単独で使用しても２種以上を併用してもよい。また、これらの生分解性樹脂のうち、得られる生分解性モノフィラメントの衝撃に対する耐久性が向上するという観点から、脂肪族－芳香族共重合ポリエステルが好ましく、ＰＢＡＴ樹脂がより好ましい。 Examples of such other biodegradable resins include polyhydroxyalkanoic acid esters other than PGA resins (eg, polyhydroxybutyrate (PHB resin), polymalic acid, polyhydroxyvalerate, poly-ε-caprolactone (PCL resin). )), Polyether esters (eg, polydioxanone), copolymers of aliphatic dicarboxylic acids and aliphatic diols (eg, polybutylene succinate (PBS resin), polyethylene succinate (PES resin), polyethylene adipate (PEA resin) )), Aliphatic polyesters (eg, polytrimethylene carbonate), aliphatic polyester carbonates (eg, polyester polyurethane, polyether urethane); polybutylene adipate-butylene tele Tareto copolymer (PBAT resin), polybutylene succinate - aliphatic such butylene terephthalate coater rates copolymer (PBST resin) - such as aromatic copolymerized polyester. These biodegradable resins may be used alone or in combination of two or more. Of these biodegradable resins, aliphatic-aromatic copolyesters are preferred, and PBAT resins are more preferred from the viewpoint of improving the durability against impact of the resulting biodegradable monofilament.
　このようなその他の生分解性樹脂の重量平均分子量としては、１万～８０万が好ましく、２万～６０万がより好ましく、４万～４０万が特に好ましい。その他の生分解性樹脂の重量平均分子量が前記下限未満になると、得られる生分解性モノフィラメントの機械的強度が低下する傾向にあり、他方、前記上限を超えると、溶融状態の生分解性樹脂を吐出させることが困難となる傾向にある。なお、前記重量平均分子量はゲルパーミエーションクロマトグラフィ（ＧＰＣ）により測定したポリメチルメタクリレート換算値である。 The weight average molecular weight of such other biodegradable resins is preferably 10,000 to 800,000, more preferably 20,000 to 600,000, and particularly preferably 40,000 to 400,000. When the weight average molecular weight of the other biodegradable resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease, whereas when the upper limit is exceeded, the biodegradable resin in the molten state is reduced. It tends to be difficult to discharge. The weight average molecular weight is a polymethylmethacrylate conversion value measured by gel permeation chromatography (GPC).
　また、その他の生分解性樹脂の溶融粘度（温度：２００℃、剪断速度：１２２ｓｅｃ－１）としては、１～１００００Ｐａ・ｓが好ましく、１０～６０００Ｐａ・ｓがより好ましく、５０～４０００Ｐａ・ｓがさらに好ましく、１００～２０００Ｐａ・ｓが特に好ましい。溶融粘度が前記下限未満になると、得られる生分解性モノフィラメントの機械的強度が低下する傾向にあり、他方、前記上限を超えると溶融状態の生分解性樹脂を吐出させることが困難となる傾向にある。 Further, the melt viscosity (temperature: 200 ° C., shear rate: 122 sec-1) of other biodegradable resins is preferably 1 to 10,000 Pa · s, more preferably 10 to 6000 Pa · s, and more preferably 50 to 4000 Pa · s. More preferred is 100 to 2000 Pa · s. If the melt viscosity is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament tends to decrease, whereas if the upper limit is exceeded, it tends to be difficult to discharge the melted biodegradable resin. is there.
　本発明に用いられる生分解性樹脂はＰＧＡ系樹脂を３５質量％以上含有するものである。このような生分解性樹脂としては、ＰＧＡ系樹脂１００質量％からなるものであってもよいし、ＰＧＡ系樹脂３５質量％以上１００質量％未満と前記その他の樹脂０質量％超過６５質量％以下との混合物であってもよい。ＰＧＡ系樹脂の含有量が前記下限未満になると、得られる生分解性モノフィラメントの機械的強度が低下する。 The biodegradable resin used in the present invention contains 35% by mass or more of PGA resin. As such a biodegradable resin, it may consist of 100% by mass of PGA-based resin, 35% by mass to less than 100% by mass of PGA-based resin, and more than 0% by mass and 65% by mass or less of the other resins. And a mixture thereof. When the content of the PGA resin is less than the lower limit, the mechanical strength of the resulting biodegradable monofilament is lowered.
　また、本発明にかかる生分解性樹脂（ＰＧＡ系樹脂を３５質量％以上含有するもの）は、本発明の目的を阻害しない範囲内において、本発明にかかる生分解性樹脂に、無機フィラー、他の熱可塑性樹脂、各種添加剤（例えば、可塑剤、熱安定剤、光安定剤、防湿剤、防水剤、撥水剤、滑剤、離型剤、カップリング剤、酸素吸収剤、顔料、染料）などを配合した生分解性樹脂組成物として使用してもよい。 In addition, the biodegradable resin according to the present invention (containing 35% by mass or more of PGA-based resin) can be added to the biodegradable resin according to the present invention within the range not impairing the object of the present invention. Thermoplastic resins and various additives (for example, plasticizers, heat stabilizers, light stabilizers, moisture proofing agents, waterproofing agents, water repellents, lubricants, mold release agents, coupling agents, oxygen absorbers, pigments, dyes) You may use as a biodegradable resin composition which mix | blended.
　＜生分解性モノフィラメントの製造方法＞
　次に、本発明の生分解性モノフィラメントの製造方法について説明する。本発明の生分解性モノフィラメントの製造方法は、前述したように、紡糸工程、１次延伸工程および２次延伸工程を含む方法である。以下、各工程を詳細に説明する。 <Method for producing biodegradable monofilament>
Next, the manufacturing method of the biodegradable monofilament of this invention is demonstrated. As described above, the biodegradable monofilament manufacturing method of the present invention is a method including a spinning step, a primary stretching step, and a secondary stretching step. Hereinafter, each process will be described in detail.
　（紡糸工程）
　先ず、ＰＧＡ系樹脂を３５質量％以上含有する生分解性樹脂を押出機などを用いて溶融（好ましくは、溶融混練）する。溶融温度としては、２００～３００℃が好ましく、２３０～２８０℃がより好ましく、２４０～２７０℃が特に好ましい。溶融温度が前記下限未満になると、本発明にかかる生分解性樹脂の流動性が低下し、生分解性樹脂がノズルから吐出されず、生分解性樹脂モノフィラメントの成形が困難となる傾向にあり、他方、前記上限を超えると、本発明にかかる生分解性樹脂が着色したり、熱分解したりする傾向にある。 (Spinning process)
First, a biodegradable resin containing 35% by mass or more of a PGA-based resin is melted (preferably melt-kneaded) using an extruder or the like. The melting temperature is preferably 200 to 300 ° C, more preferably 230 to 280 ° C, and particularly preferably 240 to 270 ° C. When the melting temperature is less than the lower limit, the fluidity of the biodegradable resin according to the present invention is reduced, the biodegradable resin is not discharged from the nozzle, and it tends to be difficult to mold the biodegradable resin monofilament, On the other hand, when the upper limit is exceeded, the biodegradable resin according to the present invention tends to be colored or thermally decomposed.
　このような溶融処理は、押出機以外にも撹拌機や連続混練機などを用いて行うことができるが、短時間での処理が可能であり、その後の吐出工程への円滑な移行が可能であるという観点から押出機を用いることが好ましい。 Such a melting process can be performed using an agitator or a continuous kneader in addition to the extruder, but the process can be performed in a short time and a smooth transition to the subsequent discharge process is possible. From the viewpoint of being, it is preferable to use an extruder.
　次に、このようにして溶融した本発明にかかる生分解性樹脂を単層ノズルから吐出させ、その後、冷却（好ましくは１０℃以下、より好ましくは５℃以下の液浴中で急冷）しながらローラーなどで引き取ることによって未延伸糸が得られる。単層ノズルの温度としては、２１０～２８０℃が好ましく、２３０～２７０℃がより好ましく、２４０～２６０℃が特に好ましい。単層ノズルの温度が前記下限未満になると、本発明にかかる生分解性樹脂の流動性が低下し、生分解性樹脂がノズルから吐出されず、生分解性樹脂モノフィラメントの成形が困難となる傾向にあり、他方、前記上限を超えると、本発明にかかる生分解性樹脂が熱分解する傾向にある。 Next, the biodegradable resin according to the present invention thus melted is discharged from a single-layer nozzle, and then cooled (preferably quenched in a liquid bath at 10 ° C. or lower, more preferably 5 ° C. or lower). An undrawn yarn is obtained by taking it up with a roller or the like. The temperature of the single layer nozzle is preferably 210 to 280 ° C, more preferably 230 to 270 ° C, and particularly preferably 240 to 260 ° C. When the temperature of the single-layer nozzle is less than the lower limit, the fluidity of the biodegradable resin according to the present invention is lowered, the biodegradable resin is not discharged from the nozzle, and the biodegradable resin monofilament tends to be difficult to mold. On the other hand, when the upper limit is exceeded, the biodegradable resin according to the present invention tends to be thermally decomposed.
　また、単層ノズルの孔径は、得られる生分解性モノフィラメントの用途に応じて適宜選択され、特に制限はないが、２～１５ｍｍφが好ましく、４～１０ｍｍφがより好ましい。 The pore diameter of the single-layer nozzle is appropriately selected according to the intended use of the resulting biodegradable monofilament, and is not particularly limited, but is preferably 2 to 15 mmφ, and more preferably 4 to 10 mmφ.
　（１次延伸工程）
　次に、前記紡糸工程で得られた未延伸糸を長さ方向（引取方向）に１次延伸してモノフィラメントを得る。これにより、機械的強度に優れた生分解性モノフィラメントを得ることができる。 (Primary stretching process)
Next, the undrawn yarn obtained in the spinning step is primarily drawn in the length direction (take-off direction) to obtain a monofilament. Thereby, a biodegradable monofilament excellent in mechanical strength can be obtained.
　本発明において、１次延伸温度Ｔ１は、ＰＧＡ系樹脂のガラス転移温度をＴｇとすると、ＰＧＡ系樹脂のＴｇ＋１０℃以上の温度であること、すなわち、Ｔ１≧Ｔｇ＋１０℃を満たすことが好ましく、Ｔ１≧Ｔｇ＋１５℃を満たすことがより好ましく、Ｔ１≧Ｔｇ＋２２℃を満たすことが特に好ましい。１次延伸温度が前記下限未満になると、樹脂が十分に軟化せず、所望の延伸倍率で１次延伸することが困難となり、最終的に得られる生分解性モノフィラメントの機械的強度が低くなる傾向にある。また、１次延伸温度の上限としては、Ｔ１≦Ｔｇ＋４０℃を満たすことが好ましい。１次延伸温度が前記上限を超えると、ＰＧＡ系樹脂が結晶化するため、延伸することが困難となり、最終的に得られる生分解性モノフィラメントの機械的強度が低くなる傾向にある。なお、本発明において、ＰＧＡ系樹脂のガラス転移温度Ｔｇ（単位：℃）は、ＰＧＡ系樹脂を示差走査熱量測定装置を用いて０℃から２７０℃まで昇温速度２０℃／分で加熱し、得られたＤＳＣ曲線から求められるものである。 In the present invention, the primary stretching temperature T 1 is preferably Tg + 10 ° C. or higher of the PGA resin, that is, T 1 ≧ Tg + 10 ° C., assuming that the glass transition temperature of the PGA resin is Tg, It is more preferable to satisfy T 1 ≧ Tg + 15 ° C., and it is particularly preferable to satisfy T 1 ≧ Tg + 22 ° C. When the primary stretching temperature is less than the lower limit, the resin is not sufficiently softened, it becomes difficult to perform primary stretching at a desired stretching ratio, and the mechanical strength of the finally obtained biodegradable monofilament tends to be low. It is in. The upper limit of the primary stretching temperature, it is preferable to satisfy T 1 ≦ Tg + 40 ℃. If the primary stretching temperature exceeds the above upper limit, the PGA-based resin crystallizes, so that it becomes difficult to stretch, and the mechanical strength of the finally obtained biodegradable monofilament tends to be low. In the present invention, the glass transition temperature Tg (unit: ° C.) of the PGA resin is such that the PGA resin is heated from 0 ° C. to 270 ° C. at a heating rate of 20 ° C./min using a differential scanning calorimeter. It is obtained from the obtained DSC curve.
　また、１次延伸倍率としては、２．０～６．０倍が好ましい。１次延伸倍率が前記下限未満になると、最終的に得られる生分解性モノフィラメントの機械的強度が低くなる傾向にあり、他方、前記上限を超えると、２次延伸が困難となり、最終的に得られる生分解性モノフィラメントの衝撃に対する耐久性が低くなる傾向にある。 Further, the primary draw ratio is preferably 2.0 to 6.0 times. If the primary draw ratio is less than the lower limit, the mechanical strength of the biodegradable monofilament finally obtained tends to be low. On the other hand, if the upper limit is exceeded, the secondary draw becomes difficult and finally obtained. The biodegradable monofilaments that are produced tend to be less durable against impact.
　（２次延伸工程）
　このようにして１次延伸を施したモノフィラメントを長さ方向（引取方向）に所定の条件で２次延伸することにより、所望の生分解性モノフィラメントを得ることができる。この２次延伸により、衝撃に対する耐久性に優れた生分解性モノフィラメントを得ることができる。 (Secondary stretching process)
A desired biodegradable monofilament can be obtained by secondary-stretching the monofilament subjected to primary stretching in this way in the length direction (take-off direction) under predetermined conditions. By this secondary stretching, a biodegradable monofilament excellent in durability against impact can be obtained.
　本発明において、２次延伸温度Ｔ２は、ＰＧＡ系樹脂のＴｇ＋２２℃以下の温度であること、すなわち、Ｔ２≦Ｔｇ＋２２℃を満たすことが好ましい。２次延伸温度が前記上限を超えると、得られる生分解性モノフィラメントの衝撃に対する耐久性が低くなる。また、衝撃に対する耐久性が向上する傾向にあるという観点から、２次延伸温度Ｔ２は、Ｔ２≦Ｔｇ＋２０℃を満たすことが好ましく、Ｔ２≦Ｔｇ＋１５℃を満たすことがより好ましく、Ｔ２≦Ｔｇ＋１０℃を満たすことが更に好ましく、Ｔ２≦Ｔｇ＋５℃を満たすことが一層好ましく、Ｔ２≦Ｔｇを満たすことがより一層好ましく、Ｔ２≦Ｔｇ－５℃を満たすことが特に好ましく、Ｔ２≦Ｔｇ－１０℃を満たすことが最も好ましい。なお、２次延伸温度の下限としては、Ｔ２≧Ｔｇ－２０℃を満たすことが好ましい。２次延伸温度が前記下限未満になると、２次延伸が困難となり、最終的に得られる生分解性モノフィラメントの衝撃に対する耐久性が低くなる傾向にある。 In the present invention, the secondary stretching temperature T 2 is preferably a temperature of Tg + 22 ° C. or lower of the PGA-based resin, that is, satisfies T 2 ≦ Tg + 22 ° C. When the secondary stretching temperature exceeds the upper limit, durability of the resulting biodegradable monofilament with respect to impact becomes low. Further, from the viewpoint that durability against impact tends to improve, the secondary stretching temperature T 2 preferably satisfies T 2 ≦ Tg + 20 ° C., more preferably satisfies T 2 ≦ Tg + 15 ° C., and T 2 ≦ It is more preferable that Tg + 10 ° C. is satisfied, T 2 ≦ Tg + 5 ° C. is more preferable, T 2 ≦ Tg is further more preferable, T 2 ≦ Tg−5 ° C. is particularly preferable, and T 2 ≦ Most preferably, Tg−10 ° C. is satisfied. The lower limit of the secondary stretching temperature preferably satisfies T 2 ≧ Tg−20 ° C. When the secondary stretching temperature is less than the lower limit, secondary stretching becomes difficult, and the durability of the biodegradable monofilament finally obtained tends to be low.
　さらに、本発明において、２次延伸は、１次延伸温度Ｔ１以下の温度で行うこと、すなわち、２次延伸温度Ｔ２が、Ｔ２≦Ｔ１を満たすことが好ましい。２次延伸温度が１次延伸温度より高くなると、得られる生分解性モノフィラメントの衝撃に対する耐久性が低くなる傾向にある。また、２次延伸温度Ｔ２は、Ｔ２≦Ｔ１－５℃を満たすことがより好ましく、Ｔ２≦Ｔ１－１０℃を満たすことが更に好ましく、Ｔ２≦Ｔ１－１５℃を満たすことが一層好ましく、Ｔ２≦Ｔ１－２０℃を満たすことがより一層好ましく、Ｔ２≦Ｔ１－２５℃を満たすことがより特に好ましく、Ｔ２≦Ｔ１－３０℃を満たすことが最も好ましい。 Further, in the present invention, the secondary drawing is be carried out in the primary stretching temperature T 1 of the following temperatures, i.e., secondary stretching temperature T 2 preferably satisfies the T 2 ≦ T 1. When the secondary stretching temperature is higher than the primary stretching temperature, the durability of the resulting biodegradable monofilament with respect to impact tends to be low. Further, the secondary stretching temperature T 2 preferably satisfies T 2 ≦ T 1 −5 ° C., more preferably satisfies T 2 ≦ T 1 −10 ° C., and satisfies T 2 ≦ T 1 −15 ° C. Is more preferable, T 2 ≦ T 1 −20 ° C. is more preferable, T 2 ≦ T 1 −25 ° C. is more preferable, and T 2 ≦ T 1 −30 ° C. is most preferable. preferable.
　なお、従来のモノフィラメントの製造方法において２段階の延伸を施す場合、得られるモノフィラメントの機械的強度を確保するために、通常、１次延伸時の温度より高い温度（すなわち、Ｔ２＞Ｔ１）で２次延伸が行われる。これに対して、本発明においては、上記のように、１次延伸時の温度以下の温度で２次延伸を行うことによって、得られるモノフィラメントの衝撃に対する優れた耐久性を確保する。 In addition, when performing the two-stage stretching in the conventional monofilament manufacturing method, in order to ensure the mechanical strength of the resulting monofilament, the temperature is usually higher than the temperature during the primary stretching (that is, T 2 > T 1 ). The secondary stretching is performed. On the other hand, in the present invention, as described above, the secondary stretching is performed at a temperature equal to or lower than the temperature during the primary stretching, thereby ensuring excellent durability against the impact of the obtained monofilament.
　また、本発明において、２次延伸倍率は、１．０２～１．６倍である。２次延伸倍率が前記下限未満になると、最終的に得られる生分解性モノフィラメントの衝撃に対する耐久性が、２次延伸を施さなかった場合に比べて向上せず、また、前記上限を超えると、モノフィラメントが破断する。 In the present invention, the secondary stretching ratio is 1.02 to 1.6 times. When the secondary stretching ratio is less than the lower limit, the durability of the biodegradable monofilament finally obtained is not improved compared to the case where the secondary stretching is not performed, and when the upper limit is exceeded, The monofilament breaks.
　このようにして得られた生分解性モノフィラメントは、機械的強度に優れるだけでなく、衝撃に対する耐久性に優れている。従って、本発明の方法によって製造された生分解性モノフィラメントは、衝撃に対する耐久性が要求される用途、例えば、刈払機の草刈りコードなどに使用することが可能である。 The biodegradable monofilament thus obtained has not only excellent mechanical strength but also excellent durability against impact. Therefore, the biodegradable monofilament produced by the method of the present invention can be used for applications that require durability against impacts, such as mowing cords for brush cutters.
　また、本発明にかかる２次延伸による効果（衝撃による耐久性の向上）は生分解性モノフィラメントの太さに依存しない。このため、本発明においては、得られる生分解性モノフィラメントの直径を用途に応じて適宜選択することができ、例えば、刈払機の草刈りコードとして使用する場合には、１．４～３ｍｍが好ましい。 Also, the effect of secondary stretching according to the present invention (improvement of durability by impact) does not depend on the thickness of the biodegradable monofilament. Therefore, in the present invention, the diameter of the obtained biodegradable monofilament can be appropriately selected depending on the application. For example, when used as a mowing cord of a brush cutter, 1.4 to 3 mm is preferable.
　以下、実施例および比較例に基づい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限定されるものではない。なお、ＰＧＡ系樹脂のガラス転移温度は以下の方法により測定した。 Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. In addition, the glass transition temperature of PGA-type resin was measured with the following method.
　＜ガラス転移温度＞
　ＰＧＡ系樹脂ペレット５ｍｇを容量４０μｌのアルミパンに秤量し、これを示差走査熱量測定装置（（株）島津製作所製「ＤＳＣ６０Ａ」）に装着して、０℃から２７０℃まで昇温速度２０℃／分で加熱し、得られたＤＳＣ曲線からガラス転移温度Ｔｇ（単位：℃）を求めた。 <Glass transition temperature>
5 mg of PGA-based resin pellets are weighed into an aluminum pan with a capacity of 40 μl, and this is mounted on a differential scanning calorimeter (“DSC60A” manufactured by Shimadzu Corporation), and the temperature increase rate from 0 ° C. to 270 ° C. is 20 ° C. / The glass transition temperature Tg (unit: ° C.) was determined from the obtained DSC curve.
　（実施例１）
　ペレット状のＰＧＡ樹脂（（株）クレハ製、ガラス転移温度：３８℃、重量平均分子量：１９万、溶融粘度（温度２７０℃、剪断速度１２２ｓｅｃ－１）：３５０Ｐａ・ｓ、融点：２２０℃）を原料ホッパーからシリンダー径３５ｍｍφの一軸押出機に投入し、２３０～２５０℃で溶融させた。なお、押出機のシリンダー温度は２３０～２５０℃に設定し、アダプタ温度、ギアポンプ温度はいずれも２５０℃に設定した。 (Example 1)
Pellet PGA resin (manufactured by Kureha Co., Ltd., glass transition temperature: 38 ° C., weight average molecular weight: 190,000, melt viscosity (temperature 270 ° C., shear rate 122 sec-1): 350 Pa · s, melting point: 220 ° C.) The raw material hopper was charged into a single screw extruder with a cylinder diameter of 35 mmφ and melted at 230 to 250 ° C. The cylinder temperature of the extruder was set to 230 to 250 ° C., and the adapter temperature and gear pump temperature were both set to 250 ° C.
　この溶融ＰＧＡ樹脂をギアポンプを用いて２５０℃に設定した単層ノズル（孔径８ｍｍφ）から１１０ｇ／分で吐出させ、５℃の水浴中で急冷しながら引取速度４ｍ／分で引き取った。その後、得られたＰＧＡ樹脂未延伸糸を６０℃（ＰＧＡ樹脂のＴｇ＋２２℃）の湯浴中で加熱しながら引取方向（長さ方向）に延伸倍率４．０倍で１次延伸し、得られたモノフィラメントをさらに２３℃（ＰＧＡ樹脂のＴｇ－１５℃）で引取方向（長さ方向）に延伸倍率１．２倍で２次延伸して、直径２．３ｍｍの生分解性モノフィラメントを得た。 The molten PGA resin was discharged at 110 g / min from a single-layer nozzle (hole diameter 8 mmφ) set at 250 ° C. using a gear pump, and was taken out at a take-up speed of 4 m / min while rapidly cooling in a 5 ° C. water bath. Thereafter, the obtained unstretched PGA resin yarn was primarily stretched in the take-off direction (length direction) at a draw ratio of 4.0 times while being heated in a 60 ° C. (Pg resin Tg + 22 ° C.) hot water bath. The monofilament was further stretched at 23 ° C. (PGA resin Tg−15 ° C.) in the take-up direction (length direction) at a draw ratio of 1.2 times to obtain a biodegradable monofilament having a diameter of 2.3 mm.
　＜衝撃耐久試験＞
　エンジン刈払機（日立工機（株）製「ＦＣＧ２２ＥＡＳＰ（Ｓ）」）の回転部にマニュアル・ローター（スターティング工業（株）製「Ｇ２００３０６」）を装着し、このローターから２０ｃｍの長さで出るようにモノフィラメントをローターに取り付けた。 <Impact durability test>
A manual rotor ("G200306" manufactured by Starting Industry Co., Ltd.) is mounted on the rotating part of the engine brush cutter ("FCG22EASP (S)" manufactured by Hitachi Koki Co., Ltd.), and it comes out of this rotor with a length of 20cm. A monofilament was attached to the rotor as described above.
　刈払機の最高回転数の１／２の回転数でローターを回転させながら、モノフィラメントの先端がコンクリート壁に常に接触するように刈払機を保ち、ローターとモノフィラメントの接触部においてモノフィラメントが切断されるまでの時間を測定し、これを耐久時間として衝撃に対する生分解性モノフィラメントの耐久性を評価した。その結果を表１に示す。 While rotating the rotor at half the maximum speed of the brush cutter, keep the brush cutter so that the tip of the monofilament always contacts the concrete wall until the monofilament is cut at the contact point between the rotor and the monofilament. The durability of the biodegradable monofilament with respect to impact was evaluated using this as the durability time. The results are shown in Table 1.
　（実施例２）
　１次延伸後のモノフィラメントを乾熱槽中、１５０℃で熱処理した後、２次延伸を行なった以外は実施例１と同様にして、直径２．３ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Example 2)
A biodegradable monofilament having a diameter of 2.3 mm was prepared in the same manner as in Example 1 except that the monofilament after the primary stretching was heat-treated at 150 ° C. in a dry heat bath and then subjected to the secondary stretching. Durability was evaluated. The results are shown in Table 1.
　（実施例３～４）
　２次延伸倍率を１．０２倍または１．５倍に変更した以外は実施例２と同様にして、直径２．４ｍｍまたは２．２ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Examples 3 to 4)
A biodegradable monofilament having a diameter of 2.4 mm or 2.2 mm was produced in the same manner as in Example 2 except that the secondary draw ratio was changed to 1.02 times or 1.5 times, and durability against impact was evaluated. did. The results are shown in Table 1.
　（実施例５～６）
　２次延伸時の温度を４０℃（ＰＧＡ樹脂のＴｇ＋２℃）または６０℃（ＰＧＡ樹脂のＴｇ＋２２℃）に変更した以外は実施例２と同様にして、直径２．３ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Examples 5 to 6)
A biodegradable monofilament having a diameter of 2.3 mm was produced in the same manner as in Example 2 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 1.
　（実施例７）
　１次延伸倍率を３．０倍に変更した以外は実施例２と同様にして、直径２．４ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Example 7)
A biodegradable monofilament having a diameter of 2.4 mm was produced in the same manner as in Example 2 except that the primary draw ratio was changed to 3.0, and durability against impact was evaluated. The results are shown in Table 1.
　（比較例１～２）
　２次延伸を行わなかった以外は実施例２または７と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Comparative Examples 1 and 2)
A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 2 or 7 except that secondary stretching was not performed, and durability against impact was evaluated. The results are shown in Table 1.
　（比較例３～５）
　２次延伸時の温度を６４℃（ＰＧＡ樹脂のＴｇ＋２６℃）、６６℃（ＰＧＡ樹脂のＴｇ＋２８℃）または７０℃（ＰＧＡ樹脂のＴｇ＋３２℃）に変更した以外は実施例２と同様にして、直径２．３ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表１に示す。 (Comparative Examples 3 to 5)
In the same manner as in Example 2, except that the temperature during secondary stretching was changed to 64 ° C. (Tg of PGA resin + 26 ° C.), 66 ° C. (Tg of PGA resin + 28 ° C.) or 70 ° C. (Tg of PGA resin + 32 ° C.). A 2.3 mm biodegradable monofilament was prepared and evaluated for durability against impact. The results are shown in Table 1.
　（実施例８）
　ペレット状のＰＧＡ樹脂（（株）クレハ製、ガラス転移温度：３８℃、重量平均分子量：１９万、溶融粘度（温度２７０℃、剪断速度１２２ｓｅｃ－１）：３５０Ｐａ・ｓ、融点：２２０℃）５０質量部とポリブチレンアジペート－ブチレンテレフターレート共重合体（ＢＡＳＦ社製「Ｅｃｏｆｌｅｘ　ＦＢＥＬＮＤ　Ｃ１２００」、ガラス転移温度：－３０℃、重量平均分子量：７４０００、溶融粘度（温度２００℃、剪断速度１２２ｓｅｃ－１）：２４０Ｐａ・ｓ、融点：１１５℃。以下、「ＰＢＡＴ樹脂」と略す。）５０質量部とを混合し、さらに、得られた混合物１００質量部に対し０．３質量部のキシレンジイソシアネート（三井化学（株）製「タケネート５００」）を反応性相溶化剤として添加した。 (Example 8)
Pellet PGA resin (manufactured by Kureha Co., Ltd., glass transition temperature: 38 ° C., weight average molecular weight: 190,000, melt viscosity (temperature: 270 ° C., shear rate: 122 sec-1): 350 Pa · s, melting point: 220 ° C.) 50 Part by mass and polybutylene adipate-butylene terephthalate copolymer ("Ecoflex FBELND C1200" manufactured by BASF, glass transition temperature: -30 ° C, weight average molecular weight: 74000, melt viscosity (temperature 200 ° C, shear rate 122 sec-1 ): 240 Pa · s, melting point: 115 ° C. Hereinafter, abbreviated as “PBAT resin”.) 50 parts by mass, and 0.3 parts by mass of xylene diisocyanate (Mitsui) with respect to 100 parts by mass of the obtained mixture. Chemical "Takenate 500") was added as a reactive compatibilizer.
　得られた混合物を原料ホッパーから二軸混練押出機（同方向回転噛み合い型、東芝機械（株）製「ＴＥＭ－２６ＳＳ」、スクリュー直径：２６ｍｍφ、Ｌ／Ｄ＝６０）に投入し、２５０℃で溶融混練した。押出機のダイから吐出した溶融状態のストランドを、３０℃の水浴中で冷却した後、ペレタイザー（サーモ・プラスティックス工業（株）製）を用いて切断し、ペレット状のＰＧＡ－ＰＢＡＴ樹脂組成物を得た。このペレット状のＰＧＡ－ＰＢＡＴ樹脂組成物を９０℃で１２時間真空乾燥したものをモノフィラメントの製造に使用した。 The obtained mixture was charged from a raw material hopper into a twin-screw kneading extruder (same-direction rotary meshing type, “TEM-26SS” manufactured by Toshiba Machine Co., Ltd., screw diameter: 26 mmφ, L / D = 60) at 250 ° C. Melt kneaded. The melted strand discharged from the die of the extruder is cooled in a water bath at 30 ° C. and then cut using a pelletizer (manufactured by Thermo Plastics Co., Ltd.) to form a pellet-like PGA-PBAT resin composition Got. The pellet-like PGA-PBAT resin composition was vacuum-dried at 90 ° C. for 12 hours and used for the production of monofilaments.
　ＰＧＡ樹脂の代わりにこのペレット状のＰＧＡ－ＰＢＡＴ樹脂組成物を用いた以外は実施例１と同様にして、直径２．３ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 A biodegradable monofilament having a diameter of 2.3 mm was prepared in the same manner as in Example 1 except that this pellet-like PGA-PBAT resin composition was used in place of the PGA resin, and durability against impact was evaluated. The results are shown in Table 2.
　（実施例９）
　１次延伸後のモノフィラメントを乾熱槽中で１５０℃、熱処理した後、延伸倍率１．１倍で２次延伸を行なった以外は実施例８と同様にして、直径２．４ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 Example 9
A biodegradability of 2.4 mm in diameter was performed in the same manner as in Example 8 except that the monofilament after primary stretching was heat-treated at 150 ° C. in a dry heat bath and then subjected to secondary stretching at a stretching ratio of 1.1 times. Monofilaments were prepared and evaluated for durability against impact. The results are shown in Table 2.
　（実施例１０）
　２次延伸倍率を１．５倍に変更した以外は実施例９と同様にして、直径２．２ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Example 10)
A biodegradable monofilament having a diameter of 2.2 mm was produced in the same manner as in Example 9 except that the secondary draw ratio was changed to 1.5, and durability against impact was evaluated. The results are shown in Table 2.
　（実施例１１）
　１次延伸倍率を３．０倍に変更した以外は実施例９と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Example 11)
A biodegradable monofilament having a diameter of 2.5 mm was produced in the same manner as in Example 9 except that the primary draw ratio was changed to 3.0, and durability against impact was evaluated. The results are shown in Table 2.
　（実施例１２～１３）
　２次延伸倍率を１．２倍または１．５倍に変更した以外は実施例１１と同様にして、直径２．４ｍｍまたは２．３ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Examples 12 to 13)
A biodegradable monofilament having a diameter of 2.4 mm or 2.3 mm was produced in the same manner as in Example 11 except that the secondary draw ratio was changed to 1.2 times or 1.5 times, and durability against impact was evaluated. did. The results are shown in Table 2.
　（実施例１４～１５）
　２次延伸時の温度を４０℃（ＰＧＡ樹脂のＴｇ＋２℃）または６０℃（ＰＧＡ樹脂のＴｇ＋２２℃）に変更した以外は実施例１１と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Examples 14 to 15)
A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 2.
　（実施例１６～１７）
　２次延伸時の温度を４０℃（ＰＧＡ樹脂のＴｇ＋２℃）または６０℃（ＰＧＡ樹脂のＴｇ＋２２℃）に変更した以外は実施例１２と同様にして、直径２．４ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Examples 16 to 17)
A biodegradable monofilament having a diameter of 2.4 mm was prepared in the same manner as in Example 12 except that the temperature during secondary stretching was changed to 40 ° C. (Pg resin Tg + 2 ° C.) or 60 ° C. (PGA resin Tg + 22 ° C.). The durability against impact was evaluated. The results are shown in Table 2.
　（実施例１８～１９）
　１次延伸の温度を７５℃（ＰＧＡ樹脂のＴｇ＋３７℃）に変更した以外は実施例９または１１と同様にして、直径２．４ｍｍまたは２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Examples 18 to 19)
A biodegradable monofilament having a diameter of 2.4 mm or 2.5 mm was produced in the same manner as in Example 9 or 11 except that the temperature of primary stretching was changed to 75 ° C. (Tg of PGA resin + 37 ° C.), and durability against impacts Sex was evaluated. The results are shown in Table 2.
　（実施例２０）
　ＰＧＡ樹脂４０質量部とＰＢＡＴ樹脂６０質量部とを混合した以外は実施例１１と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Example 20)
A biodegradable monofilament having a diameter of 2.5 mm was produced in the same manner as in Example 11 except that 40 parts by mass of PGA resin and 60 parts by mass of PBAT resin were mixed, and durability against impact was evaluated. The results are shown in Table 2.
　（実施例２１）
　ＰＧＡ樹脂６０質量部とＰＢＡＴ樹脂４０質量部とを混合した以外は実施例１１と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Example 21)
A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that 60 parts by mass of PGA resin and 40 parts by mass of PBAT resin were mixed, and durability against impact was evaluated. The results are shown in Table 2.
　（比較例６）
　２次延伸を行わなかった以外は実施例９と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Comparative Example 6)
A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 9 except that secondary stretching was not performed, and durability against impact was evaluated. The results are shown in Table 2.
　（比較例７）
　ＰＧＡ－ＰＢＡＴ樹脂組成物の代わりにＰＢＡＴ樹脂のみを用いた以外は実施例１１と同様にして、直径２．５ｍｍの生分解性モノフィラメントを作製し、衝撃に対する耐久性を評価した。その結果を表２に示す。 (Comparative Example 7)
A biodegradable monofilament having a diameter of 2.5 mm was prepared in the same manner as in Example 11 except that only the PBAT resin was used instead of the PGA-PBAT resin composition, and the durability against impact was evaluated. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１～２に示した結果から明らかなように、所定の温度および所定の倍率で２次延伸することによって、衝撃に対する耐久性に優れた生分解性モノフィラメントが得られることが確認された（実施例１～２１）。特に、２３℃で２次延伸を行なった場合には、ＰＧＡ樹脂とＰＢＡＴ樹脂とを含有する本発明の生分解性モノフィラメント（実施例８～１３、１８～２１）は、ＰＧＡ樹脂のみを含有する本発明の生分解性モノフィラメント（実施例１～４、７）に比べて、衝撃に対する耐久性が高くなることがわかった。また、表２に示した結果から明らかなように、ＰＧＡ樹脂とＰＢＡＴ樹脂とを含有する本発明の生分解性モノフィラメントにおいては、２次延伸時の温度を低くすると、衝撃に対する耐久性が向上することがわかった。 As is apparent from the results shown in Tables 1 and 2, it was confirmed that a biodegradable monofilament excellent in durability against impact can be obtained by secondary stretching at a predetermined temperature and a predetermined magnification (implementation). Examples 1 to 21). In particular, when secondary stretching is performed at 23 ° C., the biodegradable monofilaments of the present invention (Examples 8 to 13 and 18 to 21) containing the PGA resin and the PBAT resin contain only the PGA resin. As compared with the biodegradable monofilaments of the present invention (Examples 1 to 4 and 7), it was found that the durability against impact was increased. Further, as is clear from the results shown in Table 2, in the biodegradable monofilament of the present invention containing PGA resin and PBAT resin, durability against impact is improved by lowering the temperature during secondary stretching. I understood it.
　一方、１次延伸のみを施したモノフィラメント（比較例１～２および比較例６）は、所定の２次延伸をさらに施した本発明の生分解性モノフィラメント（実施例１～７および実施例８～９）に比べて、衝撃に対する耐久性に劣るものであった。また、所定の温度を超える温度（１次延伸時の温度を超える温度でもある。）で２次延伸を施したモノフィラメント（比較例３～５）は、所定の温度（１次延伸時の温度以下の温度でもある。）で２次延伸を施した本発明の生分解性モノフィラメント（実施例１～２、５～６）に比べて、衝撃に対する耐久性に劣るものであった。さらに、所定の２次延伸を施した場合でも、ＰＧＡ樹脂を含まないモノフィラメント（比較例７）は、ＰＧＡ樹脂を含む本発明の生分解性モノフィラメント（実施例１１、２０～２１）に比べて、衝撃に対する耐久性に劣るものであった。 On the other hand, monofilaments subjected only to primary stretching (Comparative Examples 1 to 2 and Comparative Example 6) are biodegradable monofilaments of the present invention (Examples 1 to 7 and Examples 8 to 8) further subjected to predetermined secondary stretching. Compared to 9), the durability against impact was inferior. In addition, monofilaments (Comparative Examples 3 to 5) subjected to secondary stretching at a temperature exceeding a predetermined temperature (which is also a temperature exceeding the temperature during primary stretching) have a predetermined temperature (below the temperature during primary stretching). As compared with the biodegradable monofilaments of the present invention (Examples 1 to 2, 5 to 6) subjected to secondary stretching in the above-described manner. Furthermore, even when the predetermined secondary stretching was performed, the monofilament not containing the PGA resin (Comparative Example 7) was compared with the biodegradable monofilament of the present invention containing the PGA resin (Examples 11 and 20 to 21). The durability against impact was inferior.
　以上説明したように、本発明によれば、ポリグリコール酸系樹脂を含有し、衝撃に対する耐久性に優れた生分解性フィラメントを得ることが可能となる。 As described above, according to the present invention, it is possible to obtain a biodegradable filament containing a polyglycolic acid resin and having excellent durability against impact.
　したがって、本発明の生分解性フィラメントの製造方法は、生分解性および衝撃に対する耐久性が要求される用途に使用されるモノフィラメント、例えば、ナイロンコードに代わる刈払機の草刈りコードなどとして有用である。 Therefore, the method for producing a biodegradable filament of the present invention is useful as a monofilament used for applications requiring biodegradability and durability against impact, for example, a mowing cord for a brush cutter in place of a nylon cord.

Claims (5)

  1. 　ポリグリコール酸系樹脂を３５質量％以上含有する生分解性樹脂を溶融紡糸して未延伸糸を得る工程と、
    　前記未延伸糸を長さ方向に１次延伸してモノフィラメントを得る工程と、
    　前記１次延伸後のモノフィラメントを長さ方向に、前記ポリグリコール酸系樹脂のガラス転移温度＋２２℃以下の温度で１．０２～１．６倍に２次延伸する工程と、
    を含む、生分解性モノフィラメントの製造方法。     A step of melt spinning a biodegradable resin containing 35% by mass or more of a polyglycolic acid resin to obtain an undrawn yarn;
    A step of primarily stretching the unstretched yarn in the length direction to obtain a monofilament;
    A step of subjecting the monofilament after the primary stretching to a lengthwise direction and a secondary stretching of 1.02 to 1.6 times at a glass transition temperature of the polyglycolic acid resin + 22 ° C. or lower;
    A method for producing a biodegradable monofilament.
  2. 　前記生分解性樹脂が脂肪族－芳香族共重合ポリエステルを更に含むものである、請求項１に記載の生分解性モノフィラメントの製造方法。 The method for producing a biodegradable monofilament according to claim 1, wherein the biodegradable resin further contains an aliphatic-aromatic copolymer polyester.
  3. 　前記未延伸糸を前記ポリグリコール酸系樹脂のガラス転移温度＋１０℃以上の温度で２．０～６．０倍に１次延伸する、請求項１または２に記載の生分解性モノフィラメントの製造方法。 The method for producing a biodegradable monofilament according to claim 1 or 2, wherein the unstretched yarn is primarily stretched by 2.0 to 6.0 times at a glass transition temperature of the polyglycolic acid resin + 10 ° C or higher. .
  4. 　前記１次延伸時の温度が前記ポリグリコール酸系樹脂のガラス転移温度＋２２℃以上の温度である、請求項３に記載の生分解性モノフィラメントの製造方法。 The method for producing a biodegradable monofilament according to claim 3, wherein the temperature during the primary stretching is a glass transition temperature of the polyglycolic acid resin + 22 ° C or higher.
  5. 　前記１次延伸時の温度以下の温度で２次延伸する、請求項１～４のうちのいずれか一項に記載の生分解性モノフィラメントの製造方法。 The method for producing a biodegradable monofilament according to any one of claims 1 to 4, wherein the film is secondarily stretched at a temperature equal to or lower than the temperature during the first stretching.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017132076A (en) * 2016-01-26 2017-08-03 一成 増谷 Glossiness filament for melting laminate type 3d printer

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JP2000027030A (en) * 1998-07-03 2000-01-25 Unitika Ltd Polylactic acid monofilament and its production
WO2005090657A1 (en) * 2004-03-18 2005-09-29 Kureha Corporation Filament of polyglycolic acid resin and process for producing the same
WO2012066955A1 (en) * 2010-11-15 2012-05-24 株式会社クレハ Polyglycolic acid resin undrawn yarn, polyglycolic acid resin drawn yarn using same, and method for producing each
JP2012251277A (en) * 2011-06-07 2012-12-20 Kureha Corp Biodegradable aliphatic polyester drawn yarn and method for producing the same

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Publication number Priority date Publication date Assignee Title
JP2000027030A (en) * 1998-07-03 2000-01-25 Unitika Ltd Polylactic acid monofilament and its production
WO2005090657A1 (en) * 2004-03-18 2005-09-29 Kureha Corporation Filament of polyglycolic acid resin and process for producing the same
WO2012066955A1 (en) * 2010-11-15 2012-05-24 株式会社クレハ Polyglycolic acid resin undrawn yarn, polyglycolic acid resin drawn yarn using same, and method for producing each
JP2012251277A (en) * 2011-06-07 2012-12-20 Kureha Corp Biodegradable aliphatic polyester drawn yarn and method for producing the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017132076A (en) * 2016-01-26 2017-08-03 一成 増谷 Glossiness filament for melting laminate type 3d printer

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