JP2010084286A - Polylactic acid-based monofilament yarn and fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid-based monofilament yarn which is excellent in biodegradability and is suitable for obtaining a thin fabric with a high quality and being friendly to environment. <P>SOLUTION: The polylactic acid-based monofilament yarn is a monofilament yarn obtained by melt-spinning a poly L-lactic acid with an average molecular weight of 50,000-100,000 and an optical purity of 95.0-99.5%, orientating the resultant to make a multi-filament yarn with a total fineness of 30-600 dtex, and furthermore, dividing it into filament yarns, and has a monofilament fineness of 3-30 dtex and a hot water shrinkage of not more than 15%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a so-called straight splitting yarn, and more particularly to a polylactic acid monofilament yarn having biodegradability.

  Monofilament yarns include monofilament yarns obtained directly by spinning and drawing, and so-called straight split yarns obtained by once obtaining multifilament yarns and then dividing them one by one. . These are mainly used in the curtain field and the bridal field, and are particularly preferably used as a thin fabric for organdy that is light and has a feeling of tension.

  As an example of straight splitting yarn, for example, Patent Document 1 discloses a polyester monofilament yarn containing a calcium atom and a phosphorus atom and having a trilobal cross section as a cross-sectional shape. A thin fabric for organdy having properties and transparency can be obtained.

Patent Document 2 discloses a modified polyester monofilament yarn including an isophthalic acid component containing a metal sulfonate group and having an atypical cross section. This yarn is also suitable as a yarn constituting a thin fabric for organdy, and is advantageous in improving the color development, sharpness, strength and the like of the fabric.
JP-A-9-241923 JP-A-9-268432

  The organdy fabrics that have been proposed to date have excellent visual sensibility as described above, so that they can fully meet the demands of appearance in the curtain and bridal fields to which the fabrics belong. It was.

  However, in recent years, in order to prevent industrial waste from polluting the environment, textile products having biodegradability have attracted attention, and the demand for biodegradability has also increased in thin fabrics for organdy. However, at present, a thin fabric for organdy for realizing this demand has not been studied, and of course, no straight splitting yarn for that purpose has been studied at all.

  An object of the present invention is to provide a polylactic acid-based monofilament yarn that eliminates the disadvantages of the prior art and is suitable for obtaining a high-quality, environmentally-friendly thin fabric having biodegradability. It is what.

  As a result of diligent studies to solve the above problems, the present inventors have found that if a polylactic acid monofilament yarn having biodegradability obtained by splitting a polylactic acid multifilament drawn yarn is used, a high We have found that it is possible to obtain a quality and environment-friendly thin fabric, and have reached the present invention.

  That is, in the present invention, a poly L-lactic acid having an average molecular weight of 50,000 to 100,000 and an optical purity of 95.0 to 99.5% is melt-spun and then stretched to draw a multifilament yarn having a total fineness of 30 to 600 dtex. And a monofilament yarn obtained by further splitting the fiber, wherein the single yarn fineness is 3 to 30 dtex, and the hot water shrinkage is 15% or less. In addition, this yarn includes a woven fabric having a cover factor set in a specific range using this yarn.

  ADVANTAGE OF THE INVENTION According to this invention, the polylactic acid type | system | group monofilament thread | yarn suitable for obtaining a thin fabric which has biodegradability, is high quality, and is kind to an environment can be provided.

  Hereinafter, the present invention will be described in detail.

  The present invention is directed to polylactic acid monofilament yarn having biodegradability. Since the polylactic acid-based monofilament yarn of the present invention does not have the torque that a false twisted yarn normally has, it can be said that it belongs to the range of straight split yarn.

  The monofilament yarn of the present invention is a multifilament yarn having a total molecular weight of 30 to 600 dtex after melt spinning poly L-lactic acid having an average molecular weight of 50,000 to 100,000 and an optical purity of 95.0 to 99.5%. It can be obtained by streaking and further splitting it.

  The polylactic acid forming the polylactic acid-based monofilament yarn of the present invention is mainly composed of a copolymer of optical isomers of L-lactic acid and D-lactic acid. The average molecular weight of the polylactic acid needs to be 50,000 to 100,000, and preferably 60,000 to 90,000. When the average molecular weight is less than 50,000, practical strength cannot be obtained, whereas when it exceeds 100,000, biodegradability is lowered.

  Further, the optical purity of poly L-lactic acid needs to be 95.0 to 99.5%, and preferably 97.5 to 99.0%. When the optical purity is less than 95.0%, the melting point of polylactic acid is lowered, the heat resistance of the monofilament yarn is inferior and the rate of biodegradation becomes too high. On the other hand, if it exceeds 99.5%, the crystallization of polylactic acid increases, and as a result, the rate of biodegradation becomes too slow, and it cannot be said that the properties of monofilament yarn are biodegradable.

  The total fineness of the polylactic acid-based multifilament yarn is 30 to 600 dtex, preferably 100 to 400 dtex.

  Furthermore, the yarn quality of the polylactic acid-based monofilament yarn will be described. First, the single yarn fineness is set to 3 to 30 dtex in consideration of the use and subsequent processes. When the fineness is less than 3 dtex, it becomes difficult to handle the yarn in the fabric preparation process and the weaving process, and the feeling of tension is lost even in the fabric texture. On the other hand, if it exceeds 30 dtex, the cooling effect at the time of spinning becomes poor, and as a result, problems may occur in the operation, such as easy fusion between the yarns, and there remains a problem in the splitting operability. Moreover, since the yarn physical properties of the obtained monofilament yarn are unstable, there is a problem in that the texture and quality of the fabric are deteriorated when it is made into a woven fabric.

  The hot water shrinkage of the polylactic acid monofilament yarn needs to satisfy 15% or less. When the hot water shrinkage rate exceeds 15%, the shrinkage force of the fabric becomes too strong. As a result, the fineness of the polylactic acid-based monofilament yarn is increased and the texture of the fabric is impaired. At the same time, the dimensional stability of the fabric is also lowered. In the present invention, the hot water shrinkage is particularly preferably 5 to 10%.

  In order to obtain a polylactic acid-based monofilament yarn having the above configuration, it is preferable to obtain it by directly spinning and drawing in consideration of cost. However, from the viewpoint of quality and spinnability, it is preferable to first obtain a polylactic acid-based multifilament yarn, and then split it one by one to obtain the desired yarn. Is adopted.

  As such polylactic acid-based multifilament yarn, not only one-step yarn such as spin draw yarn but also two-step yarn obtained by drawing UDY (undrawn yarn), POY (highly oriented undrawn yarn), etc. are adopted. Is possible. Polylactic acid-based multifilament yarn can be obtained by spinning from a general melt extruder. In this case, after spinning, it is preferable to keep the ambient temperature in the vicinity of the yarn until cooling and solidification within a certain temperature range. Specifically, it is preferable to set the atmospheric temperature at a position of 20 to 40 cm from the spinneret surface to 70 to 90 ° C. This is because polylactic acid has a smaller difference between the melting point and the solidification temperature than synthetic fibers such as polyethylene terephthalate and nylon 6. In other words, when a general melt spinning method is adopted, the polylactic acid-based multifilament yarn is cooled and solidified immediately after spinning, and the surface layer of the filament has a higher molecular orientation than the center of the cross section. This is because the skin core structure may be exhibited. From such a point, the ambient temperature is set in the range of 70 to 90 ° C. Thereby, the difference in orientation between the vicinity of the surface layer and the center of the filament can be relaxed.

  Here, the number of filaments of the polylactic acid-based multifilament yarn is preferably 6 to 16, and more preferably 8 to 12. When the number of filaments is less than 6, the number of polylactic acid monofilament yarns that can be collected decreases, which is not preferable from the viewpoint of production efficiency. On the other hand, if the number exceeds 16, the number of filaments of the polylactic acid-based multifilament yarn is too large, so that the filaments are entangled and difficult to open, which tends to be disadvantageous in terms of splitting operability. .

  Next, a fabric using the polylactic acid monofilament yarn of the present invention will be described. In the present invention, it is preferable to use a polylactic acid monofilament yarn for the background, and the cover factor (CF) of the fabric is preferably set to 600 to 1200. If the CF is less than 500, it is not preferable because the misalignment or moire is generated on the fabric and the quality of the fabric is impaired. On the other hand, if it exceeds 1200, the woven density becomes too high, which is inappropriate as a thin fabric.

  Such a woven fabric is suitable as a thin fabric for organdy, and since it can express an unprecedented ultrathin feeling and is a polylactic acid type, it is excellent in biodegradability.

  Next, the present invention will be specifically described with reference to examples. In addition, the measurement of each physical-property value in a polylactic acid-type monofilament yarn was based on the following.

(1) Average molecular weight It was set as the number average value of the dispersion by the GPC analysis of the 0.4 mass% chloroform solution of the sample.
(2) Biodegradability After burying the sample in soil for 6 months, the sample was taken out, measured for tensile strength, and evaluated by strength retention with respect to initial tensile strength.
(3) Single yarn fineness First, using a measuring machine having a frame circumference of 1.125 m, the monofilament yarn was wound about 200 m (frame circumference × 178 times) under a tension of 0.05 ± 0.01 cN / dtex, A cassette sample is used. Next, the mass of the cassette sample is measured using a balance (Electronic Balance manufactured by Kensei Kogyo Co., Ltd.) that can measure the number of grams of 5 digits below the comma, and the obtained numerical value is expressed by a formula (single yarn fineness (dtex) = 44.9438 × mass (g)). Measurement and calculation are performed once for each of the five packages, and the average of the calculated values is defined as the single yarn fineness (dtex) to be obtained.
(4) Hot water shrinkage rate Measured according to JIS L1013 8.18.1 skein shrinkage method (A method).
(5) Total fineness Measured in accordance with JIS L1013 8.3.1 Positive Fineness (Method B).

Example 1
Poly L-lactic acid having an optical purity of 99.0% and an average molecular weight of 73,000 is supplied to an extruder-type melt spinning machine, melt-spun from the spinneret at a spinning temperature of 210 ° C., and 20 cm long at a position 20 cm from the die surface. Warm air was blown from the spraying device, the atmospheric temperature at the inlet and outlet of the spraying device was 85 ° C. at the inlet, 78 ° C. at the outlet, and 300 dtex 10f undrawn yarn was scraped off at a spinning speed of 3000 m / min.

  Subsequently, the undrawn yarn that has been wound is supplied to a drawing machine, and drawn at a draw ratio of 1.43 times between a first roller having a surface temperature of 90 ° C. and a second roller having a surface temperature of 115 ° C. 210 dtex 10f of polylactic acid multifilament drawn yarn was obtained.

  Subsequently, the obtained polylactic acid-based multifilament drawn yarn was put on a commercially available splitting device, and the splitting speed was 600 m / min, the feed tension was 0.9 cN / dtex, and the take-up tension was 1.1 cN / dtex. Separation was performed to obtain ten polylactic acid monofilament yarns.

  The obtained polylactic acid monofilament yarn had a single yarn fineness of 21 dtex and a hot water shrinkage of 7.5%.

  Next, a plain fabric of CF962 was woven using the monofilament yarn as a warp and a fabric density of 105 / 2.54 cm in the weft direction. Then, after scouring and relaxing this, drying, intermediate setting, and high-pressure dyeing with black dye, a thin fabric for organdy was obtained.

  The obtained woven fabric had a texture and a deep dyeing effect almost equal to those of a commercially available polyester organdy woven fabric, despite using polylactic acid monofilament yarn.

(Comparative Example 1)
A polylactic acid-based multifilament drawn yarn was obtained in the same manner as in Example 1 except that the fineness of the multifilament yarn was changed to 210 dtex10f instead of 210 dtex10f.

  Then, the multifilament yarn was divided into polylactic acid monofilament yarns. At this time, the single yarn fineness of the monofilament yarn was 36 dtex, and the hot water shrinkage rate was 12.0%. However, in such a fiber separation process, there were troubles such as yarn breakage and fluff generation due to the lack of cooling effect when spinning the multifilament yarn.

  Thereafter, a plain fabric of CF1320 was woven using the obtained monofilament yarn as a warp and a fabric density of 110 / 2.54 cm in the weft direction. And it dye-processed on the same conditions as Example 1, and obtained the textile fabric. As in Example 1, this woven fabric was composed of monofilament yarns, but the yarn had a single yarn fineness of 36 dtex and lacked a soft feeling as a texture.

(Comparative Example 2)
A polylactic acid-based multifilament drawn yarn was obtained in the same manner as in Example 1 except that the fineness of the multifilament drawn yarn was changed to 210 dtex10f and 20 dtex10f.

  Then, the multifilament yarn was divided into polylactic acid monofilament yarns. At this time, the monofilament fineness of the monofilament yarn was 2.0 dtex, and the hot water shrinkage was 6.8%.

  Thereafter, the obtained monofilament yarn was used as a warp and weft, and the fabric density was 190 / 2.54 cm in the weft direction. However, from the preparation stage as well as the weaving process, there were troubles related to process passability such as thread breakage.

Next, this was dyed under the same conditions as in Example 1 to obtain a woven fabric. As in Example 1, this woven fabric was composed of monofilament yarn, but the single yarn fineness of the yarn was as thin as 2.0 dtex. Moreover, some defects caused by troubles in the textile process could be confirmed, and the quality was poor.

Claims (2)

  After melt spinning poly L-lactic acid having an average molecular weight of 50,000 to 100,000 and an optical purity of 95.0 to 99.5%, this is stretched to form a multifilament yarn having a total fineness of 30 to 600 dtex. 1. A polylactic acid monofilament yarn obtained by splitting, which has a single yarn fineness of 3 to 30 dtex and a hot water shrinkage of 15% or less. A woven fabric comprising the polylactic acid monofilament yarn according to claim 1 as a warp and weft having a cover factor (CF) of 600 to 1200.