JP4481907B2 - Original polylactic acid crimped yarn, method for producing the same, and carpet - Google Patents

Description

  This invention is excellent in bulkiness, has high toughness and wear resistance, and has a sufficient volume feeling constituted by using the original polylactic acid crimped yarn having excellent toughness and its production method, and the crimped yarn, It relates to carpets with excellent texture and wear resistance.

  Polylactic acid is a biodegradable resin that uses lactic acid obtained from starch such as corn as a raw material, and is decomposed into water and carbon dioxide by microorganisms and the like. It is attracting attention as a gentle material. Production of an option mat for a vehicle, a household roll carpet, a rug, or the like using a polylactic acid fiber that is such a biodegradable resin has been studied. If the same properties as the current nylon crimped polypropylene, polypropylene crimped and polyester crimped yarns can be obtained with this polylactic acid yarn, it can be widely used as a material for interiors as well as carpets. Is expected.

  However, the carpet using the conventional polylactic acid crimped yarn has the disadvantages that it is inferior in bulkiness, easily worn, and easily sag. Because of these drawbacks, the reality is that it has been put to practical use only for very limited purposes. This is because the properties of the polylactic acid crimped yarn, such as strength and elongation, and crimp properties are inferior to those of current nylon crimped polypropylene, polypropylene crimped yarn, and polyester crimped yarn.

  On the other hand, Patent Documents 1 to 3 are conventionally known regarding polylactic acid crimped yarn and a method for producing the same. Patent Document 1 uses a polylactic acid crimped yarn for dyeing that has a specific range of strength, crimp elongation, crimp latent, and strength retention after pressurized hot water treatment. Further, it is described that it is possible to improve the reduction in the strength and crimp characteristics of crimped yarns caused by dyeing.

  Patent Document 2 discloses a polylactic acid fiber having a flatness of 3 to 8 in single fiber cross section determined from the ratio of the long axis to the short axis of the single fiber, and the single fiber having a single fiber fineness of 5 to 25 dtex. It is described that the use of the polylactic acid flat crimped yarn composed of can make a carpet having a unique texture that is soft and bulky and has a refreshing feeling.

Patent Document 3 discloses that, as an original polylactic acid crimped yarn, a single fiber has an irregular cross-sectional shape with a degree of deformation of 1.5 to 5.5, and a relative viscosity, strength, crimp elongation, crimp It is described that the bulkiness, wear resistance, and sag resistance of a carpet can be improved by using one having a latent ratio, the number of entanglements, and the strength of entanglement points within a specific range.
JP 2005-8997 A JP 2005-48303 A JP 2005-60850 A

  However, the polylactic acid crimped yarn described in Patent Document 1 relates to a polylactic acid crimped yarn for pre-dyeing, and the polylactic acid crimped yarn for pre-dyeing is obtained by pressure hot water treatment by dyeing. , Its strength, elongation, and crimp characteristics are necessarily reduced. In particular, in the case of a dark color typified by black, it is indispensable to dye it with high-temperature hot water (for example, 120 to 130 ° C.). For this reason, physical property deterioration is remarkable. Therefore, when a dark-colored carpet is constructed using the polylactic acid crimped yarn described in Patent Document 1, the degree of improvement in bulkiness, abrasion resistance and sag resistance is still insufficient. It was.

  In addition, the polylactic acid flat crimped yarn obtained by the technique described in Patent Document 2 has insufficient yarn physical properties, particularly insufficient yarn strength (in Example 1 of Patent Document 2, the yarn strength is 1). .6, 1.7 in Example 2, 1.5 in Example 3, 1.8 in Example 4, and 1.5 cN / dtex in Example 5). Carpets constructed using are inferior in wear resistance and sag resistance, and therefore their use must be limited.

  Further, the carpet constructed using the original polylactic acid crimped yarn described in Patent Document 3 still has insufficient improvement in bulkiness, wear resistance, and sag resistance. When an optional mat, an automotive line mat, a tile carpet, and a household roll carpet are constructed, durability such as bulkiness, abrasion resistance, and sag resistance is not sufficiently satisfactory at a practical level. In Patent Document 3, there is no mention of the hot water shrinkage rate related to the orientation / crystal of the polylactic acid fiber.

  The present invention has been made in view of such a technical background, and provides an original polylactic acid crimped yarn excellent in bulkiness, high toughness and wear resistance, and a method for producing the same. An object of the present invention is to provide a carpet having a sufficient volume feeling, good texture, and excellent bulkiness, wear resistance, and sag resistance, using reduced yarn.

  In order to achieve the above-mentioned object, the present inventor has found that the physical properties such as the strength of the original polylactic acid crimped yarn are insufficient, the crimp property is insufficient, and the hot water shrinkage performance is inadequate. As a result of earnest research on improvements such as inferiority and lack of bulkiness, the cross-sectional shape of the single fiber constituting the original crimped yarn is limited to a specific configuration, the relative viscosity is limited to a specific range, and the strength and elongation are reduced. The inventors have found that the above-mentioned problems can be solved at once by limiting the degree, the total fineness, the single yarn fineness, the hot water shrinkage rate, and the dry heat crimp rate to specific ranges, thereby completing the present invention. That is, the present invention provides the following means.

[1] A polylactic acid crimped yarn having a single fiber having a substantially circular or circular cross-section and a relative viscosity of 2.5 to 3.8,
The polylactic acid crimped yarn contains 0.01 to 3% by mass of a colorant,
The polylactic acid crimped yarn has a strength of 1.75 to 3.5 cN / dtex, an elongation of 35 to 60%, a total fineness of 500 to 3500 dtex, a single yarn fineness of 2.5 to 25 dtex, and a hot water shrinkage. An original polylactic acid crimped yarn having a dry heat crimp rate of 2 to 8% and a dry heat crimp rate of 5 to 25%.

  [2] The original polylactic acid crimped yarn according to item 1 above, wherein the cross-sectional shape of the single fiber is a substantially circular shape or a circular shape having an irregularity of less than 1.5.

  [3] The original polylactic acid crimped yarn according to item 1 or 2, wherein at least one pigment selected from the group consisting of inorganic pigments and organic pigments is used as the colorant.

  [4] A carpet configured by using the original polylactic acid crimped yarn according to any one of items 1 to 3 as at least a part of constituent fibers.

  [5] Spinning a polylactic acid composition containing a colorant and polylactic acid, having a colorant content of 0.01 to 3% by mass and a relative viscosity of 2.5 to 3.8, A spinning step for obtaining a spun yarn having a substantially circular shape or a circular shape with a profile of less than 1.5, and a step of stretching the spun yarn 3 to 6 times by a stretching roller set at 70 to 125 ° C; A step of heat setting the drawn spun yarn by a heat setting roller set at 100 to 150 ° C., and a heating fluid crimping device is applied to the heat-set drawn yarn with a heating fluid crimping device. A crimping step of imparting crimps to the yarn by contact, and a step of cooling the crimped yarn that has undergone the crimping step to a temperature lower than the glass transition temperature of the yarn. A method for producing a poly (lactic acid) crimped yarn.

  [6] A polylactic acid composition containing a colorant and polylactic acid, having a colorant content of 0.01 to 3% by mass and a relative viscosity of 2.5 to 3.8 is extruded from a spinneret and has a cross-sectional shape. A spinning step of obtaining a substantially circular or circular filament having a degree of irregularity of less than 1.5, cooling the filament with cold air, and then coating the filament with an oil agent to obtain a spun yarn; A step of stretching 3 to 6 times by a stretching roller set to ° C., a step of heat setting the stretched spun yarn by a heat setting roller set to 100 to 150 ° C., and the heat-set drawn yarn A crimping step for imparting crimp to the yarn by contacting a heated fluid at 90 to 160 ° C. with a heating fluid crimping device, and the glass transition temperature of the crimped yarn after the crimping step. To lower temperatures Dyed polylactic acid crimped yarn manufacturing method which is characterized in that it comprises the step of retirement.

[7] When the temperature of the heat setting roller is “S” and the temperature of the heating fluid in the heating fluid crimping device is “R”, the following relational expression: 30 ° C ≧ SR−10 ° C.
7. The method for producing an original polylactic acid crimped yarn according to item 5 or 6, which satisfies the above.

  [8] The raw material according to any one of items 5 to 7, wherein the drawn spun yarn is heat-set by a heat-setting roller set to a temperature of 100 ° C. or higher and lower than a softening point temperature of polylactic acid. A method for producing a poly (lactic acid) crimped yarn.

  [9] A crimp is applied to the heat-set drawn yarn by contacting the heated fluid at a temperature of 90 ° C. or higher and lower than the crystallization temperature of polylactic acid using a heating fluid crimp applying device. 9. The method for producing an original polylactic acid crimped yarn according to any one of items 5 to 8 above.

  [10] The method for producing an original polylactic acid crimped yarn according to any one of [5] to [9], wherein the crimped yarn subjected to the cooling step is entangled using an entanglement processing device.

  [11] An original polylactic acid crimped yarn produced by the production method according to any one of 5 to 10 above.

  [12] A carpet formed by using the original polylactic acid crimped yarn according to item 11 as at least a part of constituent fibers.

  In the invention of [1], the cross-sectional shape of the single fiber constituting the original crimped yarn is limited to a specific configuration, the relative viscosity is limited to a specific range, and the strength, elongation, total fineness, single yarn fineness, Since the hot water shrinkage rate and the dry heat crimp rate are limited to specific ranges, an original polylactic acid crimped yarn having excellent bulkiness, high toughness and excellent wear resistance is provided.

  In the invention of [2], since the cross-sectional shape of the single fiber is a substantially circular shape or a circular shape having an irregularity of less than 1.5, the wear resistance can be further improved.

  In the invention of [3], since at least one pigment selected from the group consisting of inorganic pigments and organic pigments is used as the colorant, the heat resistance is higher than when other colorants such as dyes are used. There is an advantage that the heat resistance, the light resistance and the weather resistance can be improved (that is, since the dye is easily decomposed by heat, sufficient heat resistance cannot be obtained).

  The carpet according to the invention of [4] is configured by using the original polylactic acid crimped yarn of any one of the constitutions [1] to [3] as at least a part of the constituent fibers. It has a good texture and is excellent in bulkiness, wear resistance and sag resistance.

  In the invention of [5], an original polylactic acid crimped yarn having excellent bulkiness, high toughness and excellent wear resistance can be produced. In addition, since the original polylactic acid is used as a spinning raw material, there is no need to provide a dyeing step with heat treatment as a subsequent step, and this has the advantage of avoiding adverse effects (such as a decrease in mechanical strength) due to heat treatment. .

  In the invention of [6], an original polylactic acid crimped yarn having excellent bulkiness, high toughness and excellent wear resistance can be produced. In addition, since the original polylactic acid is used as a spinning raw material, there is no need to provide a dyeing step with heat treatment as a subsequent step, and this has the advantage of avoiding adverse effects (such as a decrease in mechanical strength) due to heat treatment. . In addition, since a polylactic acid composition is extruded from a spinneret to obtain filaments, the filaments are cooled with cold air, and then the filaments are coated with an oil agent to obtain a spun yarn. The coating can impart smoothness and antistatic properties to the yarn. Furthermore, since the crimped yarn is cooled to a temperature lower than the glass transition temperature of the yarn, an original polylactic acid crimped yarn imparted with sufficient crimp can be produced.

In the invention of [7], when the temperature of the heat setting roller is “S” and the temperature of the heated fluid in the heated fluid crimping device is “R”, the following relational expression: 30 ° C. ≧ SR−10 ℃
Therefore, the strength and elongation of the obtained original polylactic acid crimped yarn can be improved.

  In the invention of [8], the drawn spun yarn is heat set by a heat setting roller set at a temperature of 100 ° C. or higher and lower than the softening point temperature of polylactic acid. Both the strength and the elongation of the crimped yarn can be improved.

  In the invention of [9], the heated set crimped yarn is brought into contact with a heated fluid having a temperature of 90 ° C. or higher and lower than the crystallization temperature of polylactic acid by using a heated fluid crimping device. Since the shrinkage is imparted, damage to the fibers at the time of crimping of the oriented and crystallized polylactic acid fiber is reduced, thereby improving the strength and elongation of the obtained original polylactic acid crimped yarn. .

  In the invention of [10], the crimped yarn that has undergone the cooling process is entangled using the entanglement processing device, so that the tuftability of the crimped yarn during tufting can be improved.

  In the invention of [11], an original polylactic acid crimped yarn having excellent bulkiness, high toughness and excellent wear resistance is provided.

  In the invention of [12], a carpet having sufficient volume feeling, good texture, and excellent in bulkiness, abrasion resistance and sag resistance is provided.

  The original polylactic acid crimped yarn according to the present invention has single fibers having a substantially circular or circular cross section, and the crimped yarn has a relative viscosity of 2.5 to 3.8. The original polylactic acid crimped yarn of the present invention comprises a polylactic acid composition containing a colorant and polylactic acid.

  The polylactic acid constituting the polylactic acid composition used as the raw material of the original polylactic acid crimped yarn of this invention is a polylactic acid obtained by polymerizing a lactic acid monomer containing L-lactic acid as a main component. It is preferable to employ a configuration in which 90% by mass or more of the lactic acid monomer is composed of L-lactic acid. That is, the lactic acid monomer may contain D-lactic acid within a range not exceeding 10% by mass. If the optical purity of the lactic acid monomer used (optical purity of the L isomer) is 90% or more, the polymer (polylactic acid) is preferably crystalline, and the optical purity of the lactic acid monomer used (optical purity of the L isomer) is 97. % Or more, the melting point is around 170 ° C., which is even more preferable. Moreover, as long as the effect of this invention is not inhibited, what copolymerized components other than lactic acid may be used. When components other than lactic acid are copolymerized, 70% by mass or more and less than 100% by mass, preferably 80% by mass or more and less than 100% by mass, more preferably 90% by mass or more and less than 100% by mass, based on all repeating units of the polymer molecular chain. Lactic acid unit.

  The relative viscosity (RV) of the original polylactic acid crimped yarn of this invention needs to be 2.5 to 3.8. Here, the relative viscosity is a value measured with a mixed solution of 20 ° C. and phenol / tetrachloroethane = 60/40 (mass ratio). When the relative viscosity is less than 2.5, sufficient strength and elongation cannot be imparted to the polylactic acid crimped yarn, and abrasion resistance suitable for carpet use cannot be imparted. On the other hand, if the relative viscosity exceeds 3.8, the melt viscosity becomes too high, so that it is necessary to raise the spinning temperature. As a result, the relative viscosity of the obtained polylactic acid crimped yarn is considerably higher than the level before melting. The strength is lowered and the strength is not sufficiently improved, and it becomes difficult to produce the yarn. Among them, the relative viscosity of the original polylactic acid crimped yarn is preferably 2.8 to 3.6.

  Moreover, the polylactic acid composition used as a raw material of the original polylactic acid crimped yarn of this invention has a constitution containing 0.01 to 3% by mass of a colorant. By setting to such a density | concentration, the color of a suitable density | concentration can be provided to a crimped yarn and the design property can be improved. Further, when the content is 0.01% by mass or more, generation of color spots due to pigment unevenness can be prevented, and when the content is 3% by mass or less, occurrence of yarn breakage can be sufficiently prevented. Especially, it is preferable that the content rate of a coloring agent is 0.05-1 mass%. The colorant may be used in combination with a commonly used dispersant (such as an olefin compound).

  As long as the effect of the present invention is not impaired, the polylactic acid composition includes other polymers (including polymer particles) other than polylactic acid, matting agents, plasticizers, flame retardants, and antistatic agents. Various additives such as an agent, a deodorant, an antibacterial agent, an antioxidant, a heat-resistant agent, a light-resistant agent, and an ultraviolet absorber may be included as necessary.

  In the original polylactic acid crimped yarn of the present invention, the cross-sectional shape of the constituent single fiber is substantially circular or circular (that is, round cross-sectional yarn). Such a cross-sectional shape makes it difficult to wear even if there is friction or the like, that is, a thread resistant to friction can be obtained. Especially, it is preferable that the cross-sectional shape of the said single fiber is a substantially circular shape or circular shape with a deformity of less than 1.5 (that is, more than 1 and less than 1.5). If the degree of deformity is 1.5 or more, the covering characteristics of the polylactic acid crimped yarn will be improved, but since the degree of deformity is high, the hard and brittle properties of polylactic acid are likely to occur, and the wear resistance of the yarn is reduced. Since it falls, it is not preferable. The irregularity is a ratio B / A between the circumscribed circle diameter (B) and the inscribed circle diameter (A) of the single yarn cross section (see FIG. 2).

Furthermore, the original polylactic acid crimped yarn of the present invention is characterized by satisfying the following properties (1) to (6).
(1) Strength: 1.75 to 3.5 cN / dtex
(2) Elongation: 35-60%
(3) Total fineness: 500-3500 dtex
(4) Single yarn fineness: 2.5 to 25 dtex
(5) Hot water shrinkage: 2-8%
(6) Dry heat crimp rate: 5 to 25%.

  The strength of the original polylactic acid crimped yarn is 1.75 to 3.5 cN / dtex. If the strength of the crimped yarn is less than 1.75 cN / dtex, a portion of the crimped yarn may be worn out when it is made into a carpet, and it is impossible to provide abrasion resistance suitable for carpet use. Among these, the strength of the original polylactic acid crimped yarn is preferably 2.0 to 3.25 cN / dtex, and more preferably 2.25 to 3.25 cN / dtex.

  The elongation of the original polylactic acid crimped yarn is 35 to 60%. If the degree of elongation of the crimped yarn is less than 35%, a portion of the crimped yarn may be worn out when it is made into a carpet, and it is impossible to provide wear resistance suitable for carpet use. Among them, the elongation of the original polylactic acid crimped yarn is preferably 40 to 55%.

  When the strength of the original polylactic acid crimped yarn is 2.0 to 3.25 cN / dtex and the elongation of the original polylactic acid crimped yarn is 40 to 55%, higher toughness is obtained. Therefore, it is preferable. However, as the strength is increased, the normal elongation decreases. When the elongation is 35% or more, the strength is 3.5 cN / dtex at the most, and when the elongation exceeds 60%, the strength is decreased. It cannot be 1.75 cN / dtex or more.

  The total fineness of the original polylactic acid crimped yarn is in the range of 500 to 3500 dtex. If it is such a range, it will become an original crimped yarn especially suitable for carpet uses, such as a tufted carpet, However, It is not limited to especially the use for such a use. Among these, the total fineness of the original polylactic acid crimped yarn is preferably in the range of 1000 to 3000 dtex.

  Further, the single yarn fineness of the original polylactic acid crimped yarn is in the range of 2.5 to 25 dtex. When the single yarn fineness is less than 2.5 dtex, it is difficult to stably produce the crimped yarn, and the carpet formed using the crimped yarn has insufficient bulkiness. On the other hand, when the single yarn fineness exceeds 25 dtex, it is difficult to obtain the yarn physical properties of the original polylactic acid crimped yarn of the present invention, and the properties of polylactic acid that are hard and brittle are likely to appear, and the crimped yarn The carpet constructed using the material has insufficient wear resistance. Such a tendency becomes conspicuous as the degree of deformity of the cross-sectional shape of the polylactic acid fiber increases at the same single yarn fineness. Therefore, it is preferable that the single fiber has a smaller degree of deformity. Among these, the single yarn fineness of the original polylactic acid crimped yarn is preferably in the range of 4 to 20 dtex, more preferably in the range of 5 to 15 dtex. In addition, within the range of the single yarn fineness of 2.5 to 25 dtex, as the single yarn fineness decreases, the property that the polylactic acid is hard and brittle can be further reduced, and the strength and elongation of the original polylactic acid crimped yarn can be reduced. Can be further improved, and the wear resistance of the carpet can be improved.

  The hot-water shrinkage rate of the original polylactic acid crimped yarn is in the range of 2 to 8%. If the hot water shrinkage is less than 2%, the degree of crystallinity of the polylactic acid crimped yarn becomes high, the polylactic acid tends to be hard and brittle, the strength and elongation are not well-balanced, and the carpet is made. Insufficient wear resistance. On the other hand, if the hot water shrinkage rate exceeds 8%, yarn shrinkage occurs during the heat setting process of the original polylactic acid crimped yarn, and there is a problem in that it is difficult to manage each step in carpet manufacturing. . Especially, it is preferable that the hot water shrinkage rate of the original polylactic acid crimped yarn is in the range of 3 to 6%.

  Further, the dry heat crimp rate of the original polylactic acid crimped yarn is in the range of 5 to 25%. This dry heat crimp rate is a parameter indicating the bulkiness of the original polylactic acid crimped yarn, and the original polylactic acid crimped yarn is treated with hot air at 100 ° C. to develop the crimp. It is a value indicating the degree. If the dry heat crimp rate is less than 5%, the crimp is insufficient, the bulkiness of the carpet is insufficient, and the anti-sag property is poor. On the other hand, polylactic acid crimped yarns having a dry heat crimp rate of more than 25% are difficult to obtain with the current production technology. Even if obtained, the carpet formed using the crimped yarn is felt-like. Become. Among these, the dry heat crimp rate of the original polylactic acid crimped yarn is preferably in the range of 8 to 20%.

  Examples of the colorant include inorganic pigments and organic pigments, and are not particularly limited as long as they can give color to the crimped yarn. Examples of the inorganic pigment include oxides such as titanium oxide, zinc white, titanium yellow, zinc-iron brown, titanium / cobalt green, cobalt green, cobalt blue, copper-iron brown, and ferrocyans such as bitumen. Silicates, ultramarine silicates, carbonates such as calcium carbonate, manganese violet phosphates, carbon black, aluminum powder, bronze powder, titanium powder-coated mica, and the like. Examples of the organic pigment include phthalocyanine series such as copper phthalocyanine blue, copper phthalocyanine green, brominated copper phthalocyanine green, perylene series such as perylene scarlet, perylene rare, and perylene maroon, and isoindolinone series.

  Among these, it is preferable to use at least one pigment selected from the group consisting of inorganic pigments and organic pigments. Among them, as the colorant, carbon black, oxide-based inorganic pigment, ferrocyanide-based inorganic pigment, silicate-based inorganic pigment, carbonate-based inorganic pigment, phosphate-based inorganic pigment, phthalocyanine-based organic pigment, In this configuration, at least one pigment selected from the group consisting of perylene organic pigments and isoindolinone organic pigments is used.

  Next, a method for producing an original polylactic acid crimped yarn having the above characteristics will be described.

  First, polylactic acid is spun to obtain a spun yarn (spinning step). For example, as shown in FIG. 1, the polylactic acid is charged from the polylactic acid charging port (10) and the colorant (pigment or the like) is charged from the coloring agent charging port (11). ), And then extruded from a spinneret (15) attached to the tip of the spinning head (14) to form a filament. At this time, the shape of the hole of the spinneret (15) is appropriately designed so that the cross-sectional shape of the obtained filament is a substantially circular shape or a circular shape having a degree of irregularity of less than 1.5. Moreover, the mixing amount of the colorant is set so that the colorant content is in the range of 0.01 to 3% by mass. The melt kneading temperature in the extruder (12) is preferably set to 210 to 235 ° C. As the polylactic acid, one having a relative viscosity of 2.8 to 3.8 is used. Those having a viscosity of 3.0 to 3.6 are preferably used. The relative viscosity is a value measured with a mixed solution of 20 ° C. and phenol / tetrachloroethane = 60/40 (mass ratio). The reason for using the one having a relative viscosity of 2.8 to 3.8 is the same as described above. In addition, as the colorant, a masterbatch obtained by adding a colorant to polylactic acid in advance may be used.

  Polylactic acid generally has an official moisture content in the polymer of 0.4 to 0.5% by mass (4000 to 5000 ppm). In order to use polylactic acid for melt spinning, the water content in the polylactic acid is preferably 0.01% by mass (100 ppm) or less, and more preferably 0.005% by mass (50 ppm) or less. Therefore, for example, the moisture in the polylactic acid is reduced by drying at 100 to 130 ° C. for about 5 hours or more using a vacuum hot air dryer. When a biaxial extruder with a vent is used as the extruder (12), undried polylactic acid can be sufficiently used, and melt spinning can be performed while maintaining the relative viscosity of polylactic acid.

  The shape and dimensions of the holes of the spinneret (15) are such that the intended original polylactic acid crimped yarn can be obtained in consideration of the melt viscosity of polylactic acid, the spinning temperature, the cooling conditions after spinning, and the like. To design.

  Next, the filament extruded from the spinneret (15) is cooled by cold air from the cold air blowing device (16) (see FIG. 1). The temperature of the cold air is preferably 10 to 30 ° C, more preferably 15 to 25 ° C.

  Thereafter, an oil agent is applied to the filament by an oil agent applying device (17), and then the yarns are converged to obtain a spun yarn. Although it does not specifically limit as said oil agent, For example, what has a smoothing agent as a main component and contains an emulsifier, an antistatic agent, etc. is mentioned. Examples of preferred oil composition include, for example, neopentyl glycol dioleate as the smoothing agent, polyoxyethylene castor oil and polyoxyalkylene sorbitan ester as the emulsifier, and polyoxyethylene alkyl as the antistatic agent. Phosphate salts are preferred. Moreover, additives, such as antioxidant and a ultraviolet absorber, may be added to the said oil agent as needed. The suitable content ratio of each component in the oil agent is 35 to 75% by mass of a smoothing agent, 20 to 60% by mass of an emulsifier, and 0.5 to 8% by mass of an antistatic agent.

  By applying the oil agent, it is possible to stably secure strength and elongation in the spinning / drawing process in the production of the original polylactic acid crimped yarn and to secure stability of the expression state of the crimp in the crimping process. it can. Further, the generation of static electricity on the carpet using the original polylactic acid crimped yarn can be suppressed, and the friction coefficient of the yarn surface can be reduced, whereby the wear resistance of the carpet skin can be further improved.

  Next, the spun yarn is wound by a take-up roller (1) that rotates at a predetermined speed. The take-up speed of the take-up roller (1) is preferably 400 to 1000 m / min. If the take-up speed is less than 400 m / min, the yarn tension at the time of spinning becomes too low, which is not preferable. On the other hand, if the take-up speed exceeds 1000 m / min, the drawing speed and crimping process become high, and thus it is difficult to manufacture with the current practical process.

  Next, the spun yarn taken up by the take-up roller (1) is hot-drawn in one or more stages using the roller groups (2), (3), and (4). That is, first, the drawn spun yarn is guided to the preheating roller (2), and the preheated roller (2) preheats the spun yarn. At this time, it is preferable to set the temperature of the preheating roller (2) in the range of 55 to 95 ° C. When the temperature is set in such a range, uniform preheating can be realized. Especially, it is more preferable to set the temperature of the preheating roller (2) in the range of 55 to 70 ° C.

  Thereafter, the spun yarn is guided from the preheating roller (2) to the drawing roller (3). At this time, the temperature of the stretching roller (3) is set in the range of 70 to 125 ° C. If it is less than 70 ° C., stretching unevenness is likely to occur, and it is difficult to sufficiently stretch, and yarn breakage is likely to occur. On the other hand, when the temperature exceeds 125 ° C., the yarn is slackened during the process. The temperature of the stretching roller (3) is preferably set in the range of 85 to 125 ° C, particularly preferably 95 to 120 ° C. In addition, within the said temperature range, the temperature of the extending | stretching roller (3) is set to a temperature higher than the temperature of the preheating roller (2).

  Moreover, a draw ratio shall be 3-6 times. If it is less than 3 times, sufficient strength can not be obtained, and if it exceeds 6 times, fluff is remarkably generated. Especially, it is preferable that the said draw ratio shall be 3.5-5.0 times.

  By setting the temperature of the drawing roller (3) in the range of 70 to 125 ° C. and setting the draw ratio to 3 to 6, the high strength and high elongation of the original polylactic acid crimped yarn of the present invention In addition, it is possible to obtain a high crimp property, which makes it possible to realize excellent bulkiness and wear resistance as a carpet when the crimped yarn is used as a constituent yarn of the carpet.

  Thereafter, the spun yarn is guided from the drawing roller (3) to the heat setting roller (4), where it is heat set. At this time, the temperature of the heat setting roller (4) is set in the range of 100 to 150 ° C. By setting to such a temperature range, moderate crystallization can be expressed as a polylactic acid fiber, and both the strength and elongation of the crimped yarn can be improved. Among them, the temperature of the heat setting roller (4) is preferably set in the range of 105 to 140 ° C, more preferably 110 to 130 ° C, and most preferably 110 to 125 ° C. Moreover, it is preferable to set the temperature of the said heat setting roller (4) to the temperature higher than the temperature of the said extending | stretching roller (3) within the range of 100-150 degreeC.

  In particular, in order to obtain the high strength, high elongation and high crimp characteristics of the original polylactic acid crimped yarn of the present invention, the temperature of the heat setting roller (4) is lower than the softening point temperature (Ts) of polylactic acid. Preferably, the temperature is set to That is, the temperature of the heat setting roller (4) is preferably set to a temperature not lower than 100 ° C. and not higher than the softening point temperature (Ts) of polylactic acid. Since the softening point temperature of polylactic acid is about 130 ° C., in other words, the temperature of the heat setting roller (4) is preferably set to 100 to 130 ° C. Among them, the temperature of the heat setting roller (4) is more preferably set to 110 to 130 ° C, and particularly preferably 110 to 125 ° C.

  Next, the drawn yarn subjected to the heat setting is led to a heated fluid crimping device (5), and the crimp is imparted to the yarn by the crimping device (5) to impart bulkiness (crimping step). . The heated fluid crimp imparting device (5) is a device that imparts crimp to the yarn by bringing the heated fluid into contact with the yarn, and the temperature of the heated fluid is set in the range of 90 to 160 ° C. If it is less than 90 ° C., sufficient crimp cannot be imparted, and if it exceeds 160 ° C., the single yarn may be fused.

  In the present embodiment, the heated fluid crimping device (5) includes a heated fluid ejection nozzle device that ejects a heated high-pressure fluid onto the yarn to randomly entangle the single yarn to form a three-dimensional crimp; A compression heat treatment apparatus that performs a compression heat treatment on the yarn under a heating fluid. The compression heat treatment apparatus is an annular apparatus in which metal plates are stacked and arranged at regular intervals, and the heated and pressurized fluid is sucked to the outside from between the metal plates. In this compression heat treatment apparatus, the yarn is folded and laminated, and stays for a certain time and is heat-treated.

  Examples of the heating fluid used in the heating fluid crimping device (5) include superheated steam and heated air. Among these, it is preferable to use heated air. Further, the temperature of the heated air is set in a range of 90 to 160 ° C., among which a range of 100 to 140 ° C. is preferable, and a range of 105 to 125 ° C. is particularly preferable. Note that the temperature of the heating fluid is within a range of 90 to 160 ° C., and an appropriate condition is selected according to the pressure and flow rate of the heating fluid, the fineness of the polylactic acid yarn to be crimped, the crimping speed, and the like. It ’s fine.

  Furthermore, in order to obtain the high strength, high elongation and high crimp characteristics of the original polylactic acid crimped yarn of the present invention, the temperature of the heating fluid is set to a temperature below the crystallization temperature (Tc) of polylactic acid. It is preferable to set. Thus, if the temperature of the heating fluid is set to a temperature of 90 ° C. or more and not more than the crystallization temperature (Tc) of polylactic acid, damage to the fibers at the time of crimping of the oriented and crystallized polylactic acid fibers is caused. As a result, the desired crimp characteristics can be reliably obtained. In addition, since the crystallization temperature of polylactic acid is about 115-120 degreeC, in other words, it is preferable to set the temperature of the said heating fluid to 90-120 degreeC. In particular, the temperature of the heating fluid is particularly preferably set to 90 to 115 ° C.

Further, when the temperature of the heat setting roller (4) is “S” and the temperature of the heating fluid in the heating fluid crimping device (5) is “R”, the following relational expression: 30 ° C. ≧ SR− ≧ -10 ° C
It is particularly preferable to satisfy When such conditions are satisfied, both the strength and elongation of the original polylactic acid crimped yarn obtained can be improved. Above all, the following relational expression 20 ° C. ≧ S−R ≧ −10 ° C.
Is more preferable, and a configuration satisfying the relationship of 15 ° C. ≧ S−R ≧ −10 ° C. is particularly preferable.

  Next, the crimped yarn (6) that has been crimped by the heated fluid crimping device (5) is cooled by a cooling drum (20). In the present embodiment, the crimped yarn (6) ejected onto the cooling drum (20) is transferred while being cooled by suction through holes formed in the surface of the cooling drum (20). It is desirable to cool the crimped yarn (6) to a temperature lower than the glass transition temperature (Tg) (57 to 60 ° C.) of the yarn by this cooling. As a result, it is possible to produce an original polylactic acid crimped yarn to which sufficient crimp is applied so that the crimp does not loosen over time. Especially, it is preferable to cool the said crimped yarn (6) to 30-55 degreeC with a cooling drum (20).

  Thereafter, the crimped yarn is entangled by passing through the nozzle of the entanglement processing device (21). It is preferable to perform the entanglement process by injecting high pressure air of 0.2 to 0.5 MPa from a direction substantially perpendicular to the running crimped yarn from the entanglement nozzle.

  Next, the crimped yarn after the entanglement process is wound around a winder (22). The winding tension at this time is preferably 0.10 cN / dtex or less. Among these, the winding tension is more preferably in the range of 0.02 to 0.07 cN / dtex, and further preferably in the range of 0.03 to 0.05 cN / dtex.

  Since the original polylactic acid crimped yarn obtained as described above is excellent in bulkiness, high toughness and excellent in abrasion resistance, it is suitably used as a constituent yarn for carpets, for example. For example, the obtained original polylactic acid crimped yarn is tufted into a base fabric to form a carpet. Although it does not specifically limit as said base fabric, For example, the nonwoven fabric etc. which consist of a polylactic acid fiber other than a polyester nonwoven fabric and a polypropylene nonwoven fabric etc. are mentioned. Among them, it is preferable to use a non-woven fabric made of polylactic acid fibers as the base fabric. In this case, the entire tuft carpet is decomposed by microorganisms and the like when discarded after use, thus contributing to the protection of the global environment. can do.

  The original polylactic acid crimped yarn according to the present invention is not particularly limited to those produced by the production method exemplified above.

  The original polylactic acid crimped yarn of the present invention may be used in either a twisted or untwisted state. For example, the untwisted yarn may be mixed with other untwisted yarns using an air entanglement equipment and used in the form of mixed yarn. You can also. The original polylactic acid crimped yarn of the present invention is twisted with other nylon crimped yarns, polypropylene crimped yarns, polyester crimped yarns, etc. to form a twisted yarn, which is used as a constituent yarn of the carpet. You can also. Considering environmentally friendly recycling, it is preferable to use polyester such as PET (polyethylene terephthalate) as the other constituent material of the carpet (a material other than the original polylactic acid crimped yarn).

  In addition, two or three of the original polylactic acid crimped yarns of the present invention were used, and an upper twist and a lower twist were applied to obtain a twisted crimped yarn (the number of twists is preferably 150 to 250 times / m), and then 100 to By performing hot air treatment at 125 ° C. or vacuum steam heat treatment at 90 to 115 ° C., a crimped yarn is obtained that is twisted and further improved in bulkiness, wear resistance and sag resistance of the crimped yarn. The crimped yarn can be tufted to constitute a high-grade carpet.

  The original polylactic acid crimped yarn of the present invention and the original polylactic acid crimped yarn obtained by the production method of the present invention are suitably used as, for example, a constituent yarn of a carpet. Thus, the carpet constituted by using the original polylactic acid crimped yarn of the present invention and the carpet constituted by using the original polylactic acid crimped yarn obtained by the production method of the present invention have sufficient bulkiness and sufficient As well as having a good volume feeling, it also has excellent wear resistance and sag resistance.

  The terms and explanations used here are used to describe the embodiments of the present invention, and the present invention is not limited to these. Within the scope of the claims, the present invention allows any design changes without departing from the spirit thereof.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
A polylactic acid crimped yarn was produced using a production apparatus having the structure shown in FIG. That is, first, a polylactic acid chip (a polymer of lactic acid monomer composed of 98% by mass of L-lactic acid and 2% by mass of D-lactic acid, a weight average molecular weight of 140000, a relative viscosity of 3.2, a glass transition temperature from a polylactic acid charging port (10). Tg: 57 ° C., melting point Tm: 170 ° C., softening point temperature Ts: 130 ° C., crystallization temperature Tc: 115 ° C.) 100 parts by mass, while carbon black masterbatch (from the colorant inlet (11)) (Composition of 75% by mass of polylactic acid and 25% by mass of carbon black) 4 parts by mass were melt-kneaded at 230 ° C. while degassing in a biaxial extruder (12) with a vent (13), and then biaxial extrusion The spinneret (15) attached to the tip of the machine (12) was extruded from 64 nozzles having a circular cross section (round cross section) at a spinning beam temperature of 225 ° C., and the three bases were spun together.

  Next, the spun yarn was cooled and solidified by cold air (20 ° C., 70% RH) from a cold air spraying device (16) to obtain a multifilament yarn comprising 192 round cross-section filaments. Next, an oil agent is applied to the yarn with an oil agent applicator (17), the yarn is focused, wound on an unheated take-up roller (1) rotating at a speed of 462 m / min, and then taken up. The yarn was preheated with a preheating roller (2) set at 462 m / min and a temperature of 70 ° C.

  Thereafter, the spun yarn is wound around a drawing roller (3) set at a speed of 489 m / min and a temperature of 105 ° C., and between the heat setting roller (4) set at a speed of 2200 m / min and a temperature of 120 ° C. Stretching was performed. The draw ratio was 4.5 times. The temperature of the heat setting roller (4) was 120 ° C. lower than the softening point temperature Ts of polylactic acid.

  Next, the drawn yarn subjected to heat setting is introduced into the heated fluid crimping device (5), and heated and pressurized air at 110 ° C. and 0.6 MPa is brought into contact with the yarn to crimp this yarn. The crimped yarn was cooled to 30 ° C. with a cooling drum (20). The temperature of the heated and pressurized air was 110 ° C., which is lower than the crystallization temperature Tc of polylactic acid. Next, the crimped yarn is subjected to an entanglement treatment of 30 pcs / m with an entanglement processing device (21), wound on a winder (22) with a winding tension of 0.05 cN / dtex and a speed of 1910 m / min. A lactic acid crimped yarn was obtained.

  The obtained original polylactic acid crimped yarn is a round cross-section yarn having a total fineness of 1448 dtex / 192 filament (single yarn fineness 7.5 dtex), a relative viscosity of 3.0, a strength of 3.12 cN / dtex, and an elongation of The shrinkage percentage was 46.6%, the hot water shrinkage ratio was 4.5%, and the dry heat crimp percentage was 11.2%.

Using two of the original polylactic acid crimped yarns obtained, after twisting and twisting at a twist rate of 180 times / m to make a combined twisted yarn, it was twisted by hot air treatment at 115 ° C., and piled for carpet It was a thread. Using this pile yarn, a cut pile was provided according to the standards of gauge: 1/10 (2.54 cm / 10 needle), stitch: 48 pieces / 10 cm, pile length: 10 mm, pile unit weight: 1500 g / m ² . I got a tufted carpet.

<Example 2>
A polylactic acid crimped yarn was produced using a production apparatus having the structure shown in FIG. That is, first, a polylactic acid chip (a polymer of lactic acid monomer composed of 98% by mass of L-lactic acid and 2% by mass of D-lactic acid, a weight average molecular weight of 140000, a relative viscosity of 3.2, a glass transition temperature from a polylactic acid charging port (10). Tg: 57 ° C., melting point Tm: 170 ° C., softening point temperature Ts: 130 ° C., crystallization temperature Tc: 115 ° C.) 100 parts by mass, while carbon black masterbatch (from the colorant inlet (11)) (Composition of 75% by mass of polylactic acid and 25% by mass of carbon black) 4 parts by mass were melt-kneaded at 230 ° C. while degassing in a biaxial extruder (12) with a vent (13), and then biaxial extrusion The spinneret (15) attached to the tip of the machine (12) was extruded from 64 nozzles having a circular cross section (round cross section) at a spinning beam temperature of 225 ° C., and the three bases were spun together.

  Next, the spun yarn was cooled and solidified by cold air (20 ° C., 70% RH) from a cold air spraying device (16) to obtain a multifilament yarn comprising 192 round cross-section filaments. Subsequently, an oil agent is applied to the yarn with an oil agent applying device (17), the yarn is focused, wound on an unheated take-up roller (1) rotating at a speed of 510 m / min, and then taken up. The yarn was preheated with a preheating roller (2) set at 516 m / min and temperature 95 ° C.

  Thereafter, the spun yarn is wound around a drawing roller (3) set at a speed of 524 m / min and a temperature of 110 ° C., and between the heat setting roller (4) set at a speed of 2200 m / min and a temperature of 125 ° C. Stretching was performed. The draw ratio was 4.3 times. The temperature of the heat setting roller (4) was set to 125 ° C. lower than the softening point temperature Ts of polylactic acid.

  Next, the drawn yarn subjected to heat setting is introduced into the heated fluid crimping device (5), and heated and pressurized air at 115 ° C. and 0.6 MPa is contacted to impart crimp to the yarn. The crimped yarn was cooled to 30 ° C. with a cooling drum (20). The temperature of the heated and pressurized air was 115 ° C. which is the same as the crystallization temperature Tc of polylactic acid. Next, the crimped yarn is subjected to an entanglement treatment of 25 pcs / m with an entanglement processing device (21), wound on a winder (22) with a winding tension of 0.05 cN / dtex and a speed of 1636 m / min. A lactic acid crimped yarn was obtained.

  The obtained original polylactic acid crimped yarn is a round cross-section yarn having a total fineness of 3200 dtex / 192 filament (single yarn fineness of 16.7 dtex), a relative viscosity of 3.0, a strength of 1.84 cN / dtex, and an elongation of It was 53.1%, the hot water shrinkage was 3.8%, and the dry heat crimp was 12.3%.

The obtained original polylactic acid crimped yarn was twisted at a twist number of 180 times / m, and then heat-treated with vacuum steam at 95 ° C. to be twisted to obtain a pile yarn for carpet. Using this pile yarn, a cut pile was prepared according to the standards of gauge: 1/10 (2.54 cm / 10 needle), stitch: 44 pieces / 10 cm, pile length: 10 mm, pile unit weight: 1500 g / m ² . I got a tufted carpet.

<Example 3>
An original polylactic acid crimped yarn was produced in the same manner as in Example 1 except that a yarn having a cross-sectional shape of a single fiber and a substantially circular shape with a degree of profile of 1.4 was used. The properties of the obtained original polylactic acid crimped yarn are as shown in Table 1. In addition, a tufted carpet was obtained in the same manner as in Example 1 by using the obtained original polylactic acid crimped yarn.

<Example 4>
An original polylactic acid crimped yarn was produced in the same manner as in Example 1 except that a yarn having a single yarn fineness of 4.1 dtex was used. The properties of the obtained original polylactic acid crimped yarn are as shown in Table 1. In addition, a tufted carpet was obtained in the same manner as in Example 1 by using the obtained original polylactic acid crimped yarn.

< Reference Example , Comparative Example 2>
An original polylactic acid crimped yarn was produced in the same manner as in Example 1 except that it was produced under the conditions shown in Table 1. The properties of the obtained original polylactic acid crimped yarn are as shown in Table 1. In addition, a tufted carpet was obtained in the same manner as in Example 1 by using the obtained original polylactic acid crimped yarn.

<Comparative Example 1>
An original polylactic acid crimped yarn was produced in the same manner as in Example 1 except that a spinneret provided with 32 nozzles having a substantially Y-shaped cross section was used as the spinneret (15).

  The obtained original polylactic acid crimped yarn is a modified cross-sectional yarn having a total fineness of 1100 dtex / 96 filaments (single yarn fineness of 11.5 dtex) and a modified degree of 2.2, having a relative viscosity of 3.0 and a strength of 1.54 cN. / Dtex, elongation was 32.0%, hot water shrinkage was 4.1%, and dry heat crimp was 12.3%.

Three of the obtained original polylactic acid crimped yarns were twisted into a twisted yarn, which was then twisted by hot air treatment at 115 ° C. to obtain a pile yarn for carpet. Using this pile yarn, a cut pile was prepared according to the standards of gauge: 1/10 (2.54 cm / 10 needle), stitch: 44 pieces / 10 cm, pile length: 10 mm, pile unit weight: 1500 g / m ² . I got a tufted carpet.

<Comparative Example 3>
A polylactic acid chip (polymer of lactic acid monomer comprising 98% by mass of L-lactic acid and 2% by mass of D-lactic acid, weight average molecular weight 220,000, relative viscosity from the polylactic acid inlet (10) in the production apparatus having the structure shown in FIG. 4.0) While charging 100 parts by mass, 4 parts by mass of carbon black masterbatch (composition of 75% by mass of polylactic acid and 25% by mass of carbon black) was introduced from the colorant inlet (11) and vented ( 13) The mixture was melt-kneaded at 230 ° C. while degassing in a twin screw extruder (12). Since the melt viscosity of polylactic acid at the outlet of the twin-screw extruder (12) is too high, the pressure loss in the polymer tube up to the spinning head (14) with a polymer tube temperature of 225 ° C is large, and the outlet of the spinning head (14) As a result, uneven discharge of polylactic acid occurred remarkably. Therefore, the temperature of the twin screw extruder (12) was set to 235 ° C, and the polymer tube temperature was set to 250 ° C. As a result, the discharge amount of polylactic acid was stabilized, but the polylactic acid was yellowed at the outlet of the spinning head (14), and smoke generation that was thought to be thermal decomposition was also generated, so that spinning could not be performed in a good state.

  In addition, the characteristic of each original polylactic acid crimped yarn was measured based on the following measuring method. Moreover, the bulkiness and abrasion resistance of the obtained tufted carpet were evaluated based on the following evaluation methods. These results are shown in Table 1.

<Relative viscosity measurement method>
The sample was dissolved in a mixed solution of phenol / tetrachloroethane = 60/40 (mass ratio) to a concentration of 1 g / dL, and the relative viscosity was measured at 20 ° C. using an Ubbelohde viscosity tube.

<Weight average molecular weight measurement method>
The sample was dissolved in chloroform so as to have a concentration of 10 mg / mL, and GPC analysis was performed by using HLC8120GPC manufactured by Tosoh, using chloroform as a solvent, and the weight average molecular weight Mw was measured. RI (infrared spectrometer) was used as a detector, and polystyrene was used as a standard substance for molecular weight.

<L-lactic acid ratio measurement method>
Polylactic acid was hydrolyzed, and the ratio of L-lactic acid was determined using high performance liquid chromatography (HPLC: Shimadzu Corporation LC10AD type) using methanolic sodium hydroxide solution (concentration: 1.0 N) as a solvent.

<Variation degree evaluation method>
After cutting the single yarn, the circumscribed circle diameter (B) and the inscribed circle diameter (A) of the single yarn were measured using an optical microscope, and the value of B / A was defined as the degree of irregularity (see FIG. 2).

<Strong elongation measurement method>
Strength (cN) and elongation (%) were measured under the conditions of a sample length of 25 cm and a tensile speed of 30 cm / min using a tensile tester of TENSORAPID3 manufactured by USTER. The strength (cN / dtex) is a value obtained by dividing the strength (cN) by the total fineness.

<Fineness measurement method>
Measurement was performed in accordance with JIS L1013.

<Hot water shrinkage measurement method>
The hot water shrinkage rate (%) was measured according to the casserole shrinkage rate (Method A) of JIS L1013. First, an original polylactic acid crimped yarn cut from a bobbin package is used as a sample. A load giving a tension of total fineness dtex × 0.882 mN (90 mg / dtex) is applied to the sample yarn, and after 10 seconds, the sample length (Ls1) is measured. After being immersed in hot water at 98 ° C. for 30 minutes in an unloaded state, it is naturally dried overnight. This dried crimped yarn is used as an original polylactic acid crimped yarn after hot water treatment. A load giving a total fineness of dtex × 0.882 mN (90 mg / dtex) is applied to the original polylactic acid crimped yarn after the hot water treatment, and after 10 seconds, the sample length (Ls2) is measured.
Hot water shrinkage (%) = {(Ls1-Ls2) / Ls1} × 100
The hot water shrinkage (%) is obtained from the above formula.

<Dry heat crimp rate measurement method>
The original polylactic acid crimped yarn cut from the bobbin package is treated with hot air at 100 ° C. for 10 minutes under no load, and then allowed to stand for 10 minutes. This yarn is the original polylactic acid crimped yarn after dry heat treatment. A constant load giving a tension of total fineness dtex × 0.882 mN (90 mg / dtex) is applied to the original polylactic acid crimped yarn after the dry heat treatment, and after 10 seconds, the sample length (Lc1) is measured. Next, after applying a constant load that gives a tension of total fineness dtex × 0.0176 mN (1.8 mg / dtex) to the original polylactic acid crimped yarn after the dry heat treatment, the sample length (Lc2) Measure.
Dry heat crimp rate (%) = {(Lc1-Lc2) / Lc1} × 100
The dry heat crimp rate (%) is obtained from the above formula.

<Bulkness evaluation>
When the carpet is viewed from directly above, the condition where the base fabric can be seen through the gaps in the pile skin is visually evaluated. “◎” indicates that the base fabric is difficult to see, “○” indicates that the base fabric is visible to some extent, Those that looked good were marked with “x”.

<Abrasion resistance evaluation>
The abrasion resistance of the carpet was evaluated using a Taber type abrasion tester specified in JIS L1096.17.3. That is, an H-18 wear wheel was used, a load of 9.8 N was applied to the wear wheel, the test stand was rotated 1000 times to wear the test piece, and the wear state was visually evaluated. Those with very little wear were marked with “◎”, those with little wear were marked with “◯”, those with some wear were “△”, and those with much wear were marked with “X”.

As can be seen from Table 1, the carpets of Examples 1 to 4 constructed using the original polylactic acid crimped yarn of the present invention had sufficient bulkiness and excellent wear resistance. On the other hand, the carpets of Comparative Examples 1 and 2 were inferior in wear resistance.

  The original polylactic acid crimped yarn of the present invention and the original polylactic acid crimped yarn obtained by the production method of the present invention are suitably used as, for example, a constituent yarn of a carpet. For example, it is suitably used as a constituent yarn for roll carpets, piece carpets, tile carpets, automotive line carpets, automotive option mats, household rugs and mats, and the like. When the carpet pile is constituted by the original polylactic acid crimped yarn of the present invention, the pile form is not particularly limited, and any pile shape such as loop pile, cut pile, cut and loop pile can be adopted. Moreover, it can be used not only as a tufted carpet but also as a constituent yarn of a woven carpet, a knitted carpet, an embroidery carpet, an adhesive carpet and the like. The carpet constituted by using the original polylactic acid crimped yarn of the present invention is decomposed by microorganisms or the like when discarded after use, and can contribute to the preservation of the global environment.

It is a schematic block diagram which shows an example of the manufacturing apparatus used with the manufacturing method of this invention. It is explanatory drawing of the irregularity degree of a thread | yarn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Preheating roller 3 ... Stretching roller 4 ... Heat set roller 5 ... Heated fluid crimping device 6 ... Crimp yarn 20 ... Cooling drum 21 ... Entanglement processing device

Claims (8)

A polylactic acid composition containing a colorant and polylactic acid, having a colorant content of 0.01 to 3% by mass and a relative viscosity of 2.5 to 3.8 is spun, and the cross-sectional shape of the single fiber is irregular. A spinning step for obtaining a spun yarn having a substantially circular shape or a circular shape having a degree of less than 1.5;
Stretching the spun yarn 3-6 times with a stretching roller set at 70-125 ° C;
Heat-setting the drawn spun yarn with a heat-setting roller set at 100 to 150 ° C .;
A crimping step of imparting crimp to the yarn by bringing the heated fluid crimping device into contact with a heated fluid at 105 to 125 ° C. using a heated fluid crimping device;
And a step of cooling the crimped yarn having undergone the crimping step to a temperature lower than the glass transition temperature of the yarn. A polylactic acid composition containing a colorant and polylactic acid, having a colorant content of 0.01 to 3% by mass and a relative viscosity of 2.5 to 3.8 is extruded from a spinneret and has a cross-sectional shape of 1 A spinning step of obtaining a spun yarn by obtaining a substantially circular or circular filament of less than .5, cooling the filament with cold air, and then coating the filament with an oil agent;
Stretching the spun yarn 3-6 times with a stretching roller set at 70-125 ° C;
Heat-setting the drawn spun yarn with a heat-setting roller set at 100 to 150 ° C .;
A crimping step for imparting crimps to the yarn by bringing the heated fluid crimping device into contact with a heated fluid at 105 to 125 ° C using a heated fluid crimping device;
And a step of cooling the crimped yarn having undergone the crimping step to a temperature lower than the glass transition temperature of the yarn. When the temperature of the heat setting roller is “S” and the temperature of the heating fluid in the heating fluid crimping device is “R”, the following relational expression 30 ° C. ≧ SR−−10 ° C.
The method for producing an original polylactic acid crimped yarn according to claim 1 or 2 , wherein: The original poly according to any one of claims 1 to 3 , wherein the drawn spun yarn is heat-set by a heat setting roller set at a temperature of 100 ° C or higher and lower than a softening point temperature of polylactic acid. A method for producing lactic acid crimped yarn. The crimp is imparted to the yarn by bringing the heat-set drawn yarn into contact with a heating fluid having a temperature of 90 ° C. or more and less than the crystallization temperature of polylactic acid using a heating fluid crimping device. The manufacturing method of the original polylactic acid crimped yarn of any one of 1-4 . The method for producing an original polylactic acid crimped yarn according to any one of claims 1 to 5 , wherein the crimped yarn subjected to the cooling step is entangled using an entanglement processing device. The original polylactic acid crimped yarn manufactured with the manufacturing method of any one of Claims 1-6 . A carpet constituted by using the original polylactic acid crimped yarn according to claim 7 as at least a part of constituent fibers.

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