JP7415557B2 - Drum-shaped package made of polylactic acid monofilament - Google Patents

Description

The present invention relates to a drum-shaped package made of polylactic acid monofilament. More specifically, the present invention relates to a drum-shaped package made of polylactic acid monofilament that provides excellent quality of gauze fabric, has excellent high-order passability during warping and weaving, and is compatible with high-speed weaving.

As environmental issues such as preventing global warming, preserving fossil resources, and reducing waste are being talked about a lot, biodegradable polymers made from biomass are attracting attention, and polylactic acid polymers are attracting particular attention as such biodegradable polymers. has been done. Polylactic acid polymer is a polymer made from lactic acid obtained by fermenting starch extracted from plants, and among biodegradable polymers using biomass, it has the best balance of transparency, mechanical properties, heat resistance, and cost. The best. Generally, methods for producing polylactic acid monofilament include a two-step method in which undrawn yarn is wound once and then stretched (Patent Document 1), or a one-step method in which the polymer is melted and then directly stretched and wound (Patent Document 1). 2, Patent Document 3), the one-step method is superior to the two-step method in terms of manufacturing cost of polylactic acid monofilament. Patent Document 2 proposes a polylactic acid monofilament package with no thread drop on the end surface, and the drawing tension is set at 0.04 cN/dtex to 0.35 cN/dtex, and the winding tension is set at 0.04 cN/dtex to 0.04 cN/dtex. A manufacturing method has been proposed in which the pressure is controlled to 20 cN/dtex. Furthermore, Patent Document 3 proposes a package that has no thread drop on the end face of a polylactic acid monofilament package, suppresses dry heat shrinkage stress in the innermost layer of the package, and improves the unwinding property of the innermost layer. There is.

Japanese Patent Application Publication No. 2001-131826 JP2013-32223A International Publication No. 2016/194578

However, in recent years, weaving speeds have been increasing in order to improve production efficiency in the weaving process, and there is a strong demand for polylactic acid monofilament packages that have good high-speed unwinding properties.

The drum-shaped package of polylactic acid monofilament described in Patent Document 3 suppresses fluctuations in unwinding tension when the monofilament is unwound from the package during warping and weaving, and also suppresses dry heat shrinkage of the innermost layer of the package. Although stress can be suppressed and the unwinding performance of the innermost layer can be improved, as the weaving speed increases, the phenomenon in which the yarn unwinds in a ring shape when unwinding from the package, So-called loop dropout occurs, and if the loop dropout is severe, the loom will stop and the high passability will deteriorate, and if the loop dropout is mild, the loom will be woven without stopping, causing a problem that the quality of the gauze fabric will deteriorate. Ta. Similarly, in the drum-shaped package of polylactic acid monofilament described in Patent Document 2, as the weaving speed increases, loops are likely to occur, and high-order passability and quality of the gauze fabric deteriorate.

The present invention overcomes the problems of the prior art and provides a drum-shaped package made of polylactic acid monofilament that provides excellent gauze fabric quality, excellent high-order passability during weaving, and good high-speed unwinding. The purpose is to provide.

The present invention employs the following configuration in order to achieve the above object. That is,
In a drum-shaped package made of polylactic acid monofilament of which 95 % by weight or more is composed of lactic acid monomer, the individual values of end surface hardness measured at 36 points at 10° intervals at a package winding thickness of 25 mm are in the range of 35 to 70. A drum-shaped package made of polylactic acid monofilament, characterized by having a CV value (coefficient of variation, %) of 15% or less.
It is .

According to the present invention, it is possible to provide a polylactic acid-based monofilament drum-shaped package that provides excellent gauze fabric quality, has excellent high-order passability during weaving, and has good high-speed unwinding properties.

FIG. 1 is a schematic front view of a polylactic acid monofilament drum-shaped package of the present invention. FIG. 1 is a schematic diagram of an example of a spinning device for producing the polylactic acid monofilament drum-shaped package of the present invention. FIG. 2 is a schematic front view for explaining the hardness measurement method carried out in the present invention. FIG. 2 is a schematic side view for explaining the hardness measurement method carried out in the present invention.

The polylactic acid-based polymer used in the present invention is a polymer having -(O-CHCH ₃ -CO)- as a repeating unit, and is obtained by polymerizing lactic acid or an oligomer of lactic acid such as lactide. Since lactic acid has two types of optical isomers, D-lactic acid and L-lactic acid, its polymers include poly(D-lactic acid) consisting only of the D-isomer, poly(L-lactic acid) consisting only of the L-isomer, and There are polylactic acid polymers made of both. As the optical purity of D-lactic acid or L-lactic acid in the polylactic acid polymer decreases, crystallinity decreases and the melting point decreases greatly. Therefore, in order to improve heat resistance, the optical purity is preferably 90% or more. However, apart from the system in which two types of optical isomers are simply mixed as described above, after blending the two types of optical isomers and forming them into fibers, a high temperature heat treatment of 140°C or higher is applied. It is more preferable to use a stereo complex in which racemic crystals are formed because the melting point can be dramatically increased.

In the present invention, the polylactic acid monofilament needs to have a proportion of lactic acid monomer constituting the polymer of 50% by weight or more from the viewpoint of preserving fossil resources and biorecycling. The lactic acid monomer constituting the polymer preferably accounts for 75% by weight or more, more preferably 95% by weight or more. Further, components other than lactic acid may be copolymerized as long as they do not impair the properties of polylactic acid within this range.

In the drum-shaped package of the present invention, it is necessary that the individual values of end surface hardness (hereinafter referred to as package end surface hardness) measured at 36 locations at 10° intervals in a region with a package winding thickness of 25 mm are in the range of 35 to 70. . The term "package end surface hardness" as used herein refers to the hardness (according to JIS K7312:1996) when an Asker rubber hardness tester type C push needle is pressed against a part of the package with a winding thickness of 25 mm. Next, measurements were taken at 36 locations while shifting the measurement positions at 10° intervals in the circumferential direction of the package, and the hardness was read at each location. By setting the package end surface hardness in the range of 35 to 70, it is possible to suppress loop defects even during high-speed unwinding, obtain excellent gauze fabric quality, and obtain a package with excellent high-order passability. If the package hardness is less than 35, the end yarns in the area will fall off due to friction with the unraveling yarn during high-speed unwinding, and the quality of the gauze fabric will tend to deteriorate due to the occurrence of loop-like defects. It is in. When the hardness of the package end face exceeds 70, the bulge (hereinafter referred to as bulge) at the end face of the package becomes large, so that high-speed unwinding properties tend to deteriorate. Preferably, the package end surface hardness is 50 to 65.

In the drum-shaped package of the present invention, it is preferable that the CV value (%) of the package end surface hardness measured at 36 locations at 10° intervals in a region with a package winding thickness of 25 mm is 15% or less. By setting the CV value (%) of the package end surface hardness to 15% or less, it is possible to suppress yarn layer collapse due to the influence of residual stress of the polylactic acid monofilament remaining in the wound package. Furthermore, since it is possible to suppress the collapse of the yarn layer due to vibrations caused when the spindle is decelerated, there is no occurrence of loop omission during high-speed unwinding, and the high-order passability and quality of the gauze fabric are good. More preferably, the CV value (%) of the package end surface hardness is 10% or less.

The method of controlling the package end surface hardness and the CV value (%) of the package end surface hardness within this range is to integrate a series of winding conditions such as winding tension, surface pressure, traverse swing width, and deceleration speed for decelerating the winding spindle. This is possible by combining them as

First, the winding tension must be 0.10 cN/dtex or less. By setting the winding tension to 0.10 cN/dtex or less, residual stress can be reduced and bulges can be suppressed. When the winding tension exceeds 0.10 cN/dtex, the bulge becomes large due to the influence of residual stress, and the hardness of the package end face at the bulge portion decreases. Furthermore, since the hardness of the package end face increases overall, variations in the hardness of the package end face are likely to occur. If the winding tension is less than 0.04 cN/dtex, the yarn winds backwards on the godet roll and breaks, so it is preferably 0.05 to 0.08 cN/dtex.

Second, the load (hereinafter referred to as surface pressure) on the length of the line where the roller bail (12 in FIG. 2) is in contact with the package (3 in FIG. 2) needs to be 125 N/m or less. By setting the surface pressure to 125 N/m or less, a package can be formed while suppressing yarn layer collapse. In addition, residual stress can be reduced, so variations in hardness of the package end face can be suppressed. When the surface pressure exceeds 125 N/m, the yarn layer collapses easily, and the hardness of the package end surface decreases at the portion where the yarn layer collapses, so that variations in the hardness of the package end surface tend to occur. If the surface pressure is less than 50 N/m, the hardness of the package end surface will be too low, making it easy for the yarn layer to collapse.The hardness of the package end surface will further decrease at the part where the yarn layer has collapsed, resulting in variations in the hardness of the package end surface. It becomes easier. Preferably it is 80 to 120 N/m.

Thirdly, it is preferable that the traverse swing width of the traverse device (11 in FIG. 2) be in the range of 3 to 5%. By setting the traverse swing width to 3 to 5%, it is possible to suppress the overlapping of the threads forming the package, and prevent the vibration of the winding device (15 in Figure 2) and the polylactic acid monofilament package (3 in Figure 2). ) can suppress the collapse of the yarn layer due to vibrations and the like until the spindle stops after reaching the specified winding amount. The oscillation period of the traverse is not particularly limited, but a period of 3 seconds to 4 seconds is preferable. The traverse method is not particularly limited, such as a 1- to 3-axis blade traverse method, a micro-cam traverse method, or a spindle method that can shorten the free length. A traverse method is preferred. If the traverse swing width is less than 3%, the yarn layer forming the package tends to collapse due to overlapping yarns, and the hardness of the package end surface decreases in the part where the yarn layer collapses, resulting in variations in the hardness of the package end surface. becomes more likely to occur. If the traverse swing width exceeds 5%, threads tend to fall to the end face of the package, resulting in poor fabric quality due to fluctuations in unwinding tension during warping and weaving.

Fourthly, it is preferable that the deceleration speed at which the spindle is decelerated after the polylactic acid monofilament package (3 in FIG. 2) reaches the specified winding amount is 20 to 70 m/sec. By setting the speed at which the spindle is decelerated to 20 to 70 m/sec, it is possible to suppress yarn layer collapse due to vibrations that occur when the spindle is decelerated. If the deceleration speed at which the spindle is decelerated exceeds 70 m/sec, the yarn layer is likely to collapse due to vibrations generated when the spindle decelerates, and the hardness of the package end surface will decrease at the part where the yarn layer has collapsed, resulting in variations in the hardness of the package end surface. becomes more likely to occur. The slower the speed at which the spindle is decelerated, the more it is possible to suppress the collapse of the yarn layer of the package, but the longer it takes for the spindle to stop, the worse the workability is. More preferably 20 to 40 m/sec, still more preferably 25 to 30 m/sec.

By combining the elements of the first to fourth winding methods described above, it is possible to suppress the hardness of the package end surface.

A good packaging foam is required because it affects the unwinding of the yarn in the next process. A detailed explanation will be given below with reference to the schematic diagram of the drum-shaped package shown in FIG. First of all, one of the drawbacks of package foam other than thread drop is the saddle (raised edge), which is expressed by the difference (B-C) between the end winding diameter B in the package winding thickness direction and the minimum winding diameter C in the package winding thickness direction. The smaller the saddle, the better the unwinding of the yarn at high speeds. The unwinding speed required in the next process reaches 1,000 to 1,200 m/min, but if the saddle is high, the saddle part will be continuously rubbed by the unwinding yarn, so polylactic acid with low abrasion resistance The surface of the fiber is scraped, resulting in a defect that corresponds to the period of the package end face (corresponding to the yarn length from one saddle to the other). In addition, the unwinding tension of the yarn in the saddle portion tends to fluctuate, which causes instability in the next process. Therefore, in order to suppress end face periodic defects and perform stable high-speed unwinding in the next process, the saddle (B-C) is preferably 6 mm or less, more preferably 4 mm or less, and even more preferably 2 mm or less. . Further, the lower limit is not particularly specified, but ideally it is 0 mm.

Additionally, there is a bulge expressed by ((maximum package winding width E - package winding width D)/package winding width D) x 100, and the smaller the bulge, the better the yarn unwinding property at high speed. If the bulge is high, the yarn will come into contact with the bulge during unwinding, making it easier for the yarn layer to collapse. Therefore, in order to suppress end face period defects and perform stable high-speed unwinding in the next step, the bulge is preferably 10% or less, more preferably 7% or less, and still more preferably 5% or less. Further, the lower limit is not particularly specified, but ideally it is 0%.

The polylactic acid monofilament constituting the drum-shaped package of the present invention preferably has a tensile strength of 2.5 cN/dtex or more. By setting it to 2.5 cN/dtex or more, thread breakage when the polylactic acid monofilament is unwound from the package during weaving can be suppressed, and good woven fabric strength can be obtained when made into a gauze fabric. . More preferably, it is 3.5 cN/dtex or more. The higher the strength, the better, but the maximum strength in the present invention is 4.3 cN/dtex. Further, the strength is determined by stretching by the speed difference between the heated first godet roll and the heated second godet roll to obtain a predetermined strength.

The elongation of the polylactic acid monofilament constituting the drum-shaped package of the present invention is preferably 35% to 55%. By setting it in this range, high-order passability during weaving and high-order processing stability when made into a gauze fabric for tea bags are improved. More preferred elongation is 35% to 45%. The elongation is determined by the speed difference between the heated first godet roll and the heated second godet roll to obtain a predetermined elongation.

The fineness of the polylactic acid monofilament constituting the drum-shaped package of the present invention is preferably 15 dtex to 40 dtex. By setting it within this range, when used as a gauze fabric for tea bags, the opening area per unit area can be set to an optimum value, and the extraction rate becomes optimum for tea, resulting in delicious tea.

The boiling water shrinkage rate of the polylactic acid monofilament constituting the drum-shaped package of the present invention is preferably 20% or less. By setting it to 20% or less, when processed into gauze fabric for tea bags, even if shrinkage occurs when hot water is poured, the opening area per unit area can be optimized, making it ideal for tea products. This results in a fast extraction speed and a delicious tea. More preferably it is 17% or less.

Next, an example of the method for manufacturing a polylactic acid monofilament package of the present invention will be explained according to the process schematic diagram of FIG. 2. FIG. 2 is a process schematic diagram showing an example of the method for manufacturing a polylactic acid monofilament package of the present invention.

The spinning block 4 in the melt spinning machine is heated by a heating means (not shown). A spinneret 5 is attached to the spinning block 4, a polylactic acid polymer is melted, and the polymer is discharged from the spinneret 5 to form yarn 1, and a cooling device (not shown) provided downstream of the spinneret 5 is used. After the yarn 1 is uniformly cooled by the device, an oil agent is applied to the yarn 1 by the oil supply device 6, and the yarn 1 is stretched between the first Godet rolls 7, 8 and the second Godet rolls 9, 10. While the yarn is traversed by the traverse device 11, it is wound up by the winding device 15 to form the package 3. When the package 3 reaches a specified winding amount, the take-up spindle 13 and the standby spindle 14 are turreted, and the yarn is automatically switched to the standby spindle 14. The package 3 located on the standby side is decelerated at a predetermined spindle deceleration speed and stopped.

In the present invention, the polylactic acid monofilament winding method combines winding conditions such as winding tension, surface pressure, traverse swing width, and deceleration speed for decelerating the winding spindle, as shown below, to improve package end surface hardness and The CV value (%) of the package end surface hardness can be set within an appropriate range.

First, it is preferable to wind the film at a winding tension of 0.04 to 0.10 cN/dtex. This winding tension is controlled by, for example, the speed difference between the first Godet rolls 7, 8 and the second Godet rolls 9, 10, or the speed difference between the second Godet rolls 9, 10 and the winding device 15.

Second, it is preferable that the surface pressure applied to the package 3 by the roller bail 12 be 50 to 125 N/m. This surface pressure is set to a predetermined pressure by adjusting the pneumatic pressure for setting the surface pressure installed in the winding device 15. For example, when setting the surface pressure to 100 N/m, if the winding width F is 70 mm and the number of windings on the paper core wound on the winding side spindle 13 is 12 drums, the pneumatic pressure for setting the surface pressure must be adjusted. , the pressure exerted by the roller bail 12 on the spindle 13 is set to 84N.

Thirdly, it is preferable that the traverse swing width of the traverse device 11 be within the range of 3 to 5%. This traverse swing width sets the swing width for the traverse setting value. For example, if the traverse swing width is 3%, the traverse setting value is 2000 cpm, and the traverse swing cycle is 4 seconds, the traverse speed swings from 1940 to 2060 cpm in a 4 second cycle.

Fourthly, it is preferable that the deceleration speed at which the spindle is decelerated after the polylactic acid monofilament package 3 reaches the specified winding amount is 20 to 70 m/sec. This spindle deceleration speed is the deceleration speed of the spindle located on the standby side when the winding side spindle 13 and the standby side spindle 14 are turreted when the polylactic acid monofilament package 3 reaches the specified winding amount, and is set. The spindle decelerates and stops at the deceleration speed.

In the method for producing a polylactic acid monofilament package of the present invention, the application of oil is carried out using a known spinning oil and oiling device. As the spinning oil, any form of commonly used spinning oil can be used, such as a straight oil diluted with mineral oil or an emulsion oil diluted with water. The smoothing agent component and emulsifier component in the spinning oil component include ester-based, mineral oil-based, ether ester-based smoothing agents, ether type nonionic surfactants having polyoxyalkylene groups in the molecule, and polyhydric alcohol moieties. Examples include ester type nonionic surfactants and polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic surfactants. Examples of the oiling device include an oiling roller type and an oiling guide type. The preferred amount of oil applied to the fibers is 0.3 to 1.0% by weight, more preferably 0.5 to 0.8% by weight.

In the method for producing a polylactic acid-based monofilament package of the present invention, heating stretching is usually performed using a Godet roll, and the heating stretching temperature is in the range of 80 to 120°C. The heated stretching is preferably carried out using a heated godet roll, and the godet roll temperature is a value actually measured with a contact thermometer.

Godet rolls include, for example, a first godet roll and a second godet roll, and since the godet roll improves thread followability, it is preferable to use a Nelson godet roll, which is a pair of two godet rolls. Taking-off is performed by the first Godet roll, and stretching is performed between Godet rolls having different speeds. For example, in the case of one-stage stretching, it is performed between the first and second godet rolls. In the case of two-stage stretching, stretching is performed between the first and second Godet rolls and between the second and third Godet rolls. Although the stretching ratio and the number of stretching steps may be any value, it is preferable that the stretching ratio is 3.5 to 4.5 times and one stage stretching is performed. The temperature of the taken Godet roll (first Godet roll) is in the range of 80°C to 120°C. By setting the first godet roll temperature to 80° C. or higher, uniform stretching without crystal structure unevenness becomes possible, and stable quality can be obtained without devitrification or decrease in tensile strength. By setting the first godet roll temperature to 120° C. or lower, yarn breakage due to a decrease in spinning tension can be suppressed, and stable operability can be obtained. More preferably the temperature is 90°C to 110°C or less.

The temperature of the stretched Godet roll (second Godet roll) is in the range of 100°C to 130°C. By setting the temperature of the second Goderol to 100° C. or higher, the oriented crystallinity can be increased and the boiling water shrinkage rate of the polylactic acid monofilament can be decreased. By setting the temperature of the second godet roll to 130° C. or lower, yarn breakage due to a decrease in winding tension can be suppressed, and stable operability can be obtained. More preferably it is 110°C to 120°C.

The cross-sectional shape of the polylactic acid monofilament constituting the drum-shaped package of the present invention may be a round cross-section, a Y-shaped cross-section, a T-shaped cross-section, a flat cross-section, or a shape that is a further modification thereof.

The present invention will be explained in more detail with reference to Examples below. In addition, the physical property values in Examples were measured by the method described below.

(1) Fineness (dtex)
Measured in accordance with JIS L1013 (2010) 8.3.1 Positive Fineness (Method A). Note that the official moisture content was 0%.

(2) Package thickness (mm)
This is the thickness A in the package winding thickness direction.

(3) Package end surface hardness This is the value indicated by the pointer of an Asker rubber hardness meter C type pressed against the end surface of the package (based on JIS K7312:1996). The measurement positions were 36 locations where the package thickness was 25 mm, and the measurement positions were shifted at 10° intervals in the circumferential direction of the package.

(4) Package edge hardness CV value (coefficient of variation, %)
The CV value (coefficient of variation) was calculated from the values measured at 36 locations where the package thickness was 25 mm (see FIGS. 3 and 4) while shifting the measurement positions at 10° intervals in the circumferential direction of the package.

(5) Bulge (%)
Calculated using the following formula.
Package winding width D/(package maximum winding width E - package winding width D) x 100.

(6) Saddle (mm)
Calculated using the following formula.
(Package maximum diameter B - package minimum diameter C)/2.

(7) Thread drop (DM/100DM)
The number of thread drop drums on both end surfaces of each 100 packages was counted.

(8) Tensile strength (cN/dtex), tensile elongation (%)
Measured according to JIS L1013 (2010) 8.5 tensile strength and elongation. Note that the gripping interval was 500 mm, and the tensile speed was 500 mm/min. The average value of three repeated measurements was used.

(9) Boiling water shrinkage rate (%)
Measured according to JIS L1013 (2010) 8.18.1. Using a measuring machine with a frame circumference of 1.125 m, the sample was made into a skein with 20 turns, and after being left for 24 hours, the length of the skein was measured, and then immersed in boiling water (99±1.0°C) for 30 minutes. The skein length after natural drying was measured, and the boiling water shrinkage rate (%) was calculated from the skein length before and after immersion in boiling water.

(10) Winding tension (cN/dtex)
The value obtained by dividing the value measured between the second godet rolls 9 and 10 and the winding device 15 shown in FIG. 2 by the fineness using Toray Engineering's TENSION METER and FT-R pickup sensor (cN/dtex) And so.

(11) Number of loose packages (DM/100DM)
100 polylactic acid monofilament drum-shaped packages with a winding thickness of 40 mm and a yarn weight of 1 kg were prepared, and each was evaluated for weft driving at a speed of 1000 m/min and 1200 m/min (package unwinding speed) using an air jet loom loom. The number of packages in which loops were removed was counted.

(12) Fabric quality We prepared 100 polylactic acid monofilament drum-shaped packages with a winding thickness of 40 mm and a yarn weight of 1 kg, and performed a weft evaluation on an air jet loom loom at a speed of 1200 m/min, and evaluated the brightness of the lighting. The appearance was inspected at a point of 250 lux or more and 1250 lux or less, and observations were made for band-like gloss differences and loop defects in the gray fabric. A is a state in which there is no band-like gloss difference or ring-out defects; B is a state in which band-like gloss differences or ring-out defects are slightly visible; C is a state in which band-like gloss differences or ring-hole defects are observed intermittently. The condition in which band-like gloss differences and ring defects were frequently observed intermittently was judged as D on a four-level scale, and A and B levels were judged as passing.

(13) Weight average molecular weight Measured using gel permeation chromatography 2690 manufactured by Waters, using polystyrene as a standard.

(14) Polylactic acid polymer (P)
Lactide produced from L-lactic acid with an optical purity of 99.5% was polymerized in the presence of a bis(2-ethylhexanoate)tin catalyst (lactide to catalyst molar ratio = 10,000:1) at 180°C for 180 minutes in a nitrogen atmosphere. Polylactic acid polymer P was obtained.

[Example 1]
Using the spinning apparatus shown in Fig. 2, polylactic acid polymer P having a weight average molecular weight of 200,000 was melted at 230°C, applied to a melt-spinning pack, and the yarn discharged from the spinneret 5 discharge hole was cooled and the oiling roller After applying straight spinning oil diluted with mineral oil (deposition amount is 0.8% by weight) using the oil supply device 6 of the system, the first Godet rolls 7 and 8 heated to 100°C and the second Godet roll heated to 115°C 9 and 10, stretched 4.0 times, and heat-treated, it was traversed using a micro-cam traverse type traverse device 11 at a winding angle of 5.6°, a traverse swing width of 3%, and a traverse swing period of 4 seconds. However, under the manufacturing conditions of surface pressure 85 N/m, RB drive OF ratio 0.1%, set winding speed (V) 3000 m/min, and spindle deceleration speed 25 m/sec, the winding width was 70 mm, the winding thickness was 40 mm, and the winding amount was 1. A drum-shaped package of polylactic acid monofilament weighing .0 kg and 25 dtex was obtained.

The end surface hardness of the package was 36 to 65, the CV value of the package end surface hardness was 10%, and the package form was in good condition with no yarn collapse or yarn fall. Using the obtained package, we carried out a weft driving evaluation (the warp yarn was polylactic acid monofilament of 25 dtex). As a result, there was no loop omission at an unwinding speed of 1000 m/min, and only 2 drums of loop omission at an unwinding speed of 1200 m/min. The level of non-occurrence and high speed unwinding were good. In addition, the quality of the woven fabric that was wefted at an unwinding speed of 1200 m/min was good, with a B level and an acceptable level, with some band-like gloss differences and ring-out defects being observed.

[Example 2]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1 except that the traverse swing width was changed to 4%. The package end surface hardness was 50 to 65, and the package end surface hardness CV value was 7%, which was good, with no yarn collapse or thread drop on the package end surface. The obtained package was subjected to horizontal driving evaluation in the same manner as in Example 1, and as a result, there was no loop omission at any unwinding speed, and the high-speed unwinding property was good. In addition, the quality of the fabric, which was wefted at an unwinding speed of 1200 m/min, was A level and good quality, with no difference in band-like gloss or loop defects. That is, the package was compatible with high-speed weaving, had excellent high-speed unwinding properties, had high passability during weaving, and had excellent gauze fabric quality.

[Example 3]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1 except that the traverse swing width was changed to 5%. The package end surface hardness was 45 to 63, and the package end surface hardness CV value was 7%, which was good with no yarn collapse or thread drop on the package end surface. As a result of performing a horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that there was no wheel dropout at an unwinding speed of 1000 m/min, and at a level that only 1 drum wheel dropout occurred even at an unwinding speed of 1200 m/min. High-speed unwinding properties were good. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was good, with a B level that showed some band-like gloss differences and ring-out defects.

[Example 4]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 4% and the spindle deceleration speed was changed to 50 m/sec. The package end surface hardness was 40 to 67, and the package end surface hardness CV value was 10%, which was good, with no yarn collapse or thread drop on the package end surface. As a result of performing a horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that there was no wheel dropout at an unwinding speed of 1000 m/min, and at a level where only 2 drums came off at an unwinding speed of 1200 m/min. High-speed unwinding properties were good. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was good, with a B level that showed some band-like gloss differences and ring-out defects.

[Example 5]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 4% and the spindle deceleration speed was changed to 70 m/sec. The package end surface hardness was 38 to 65, and the package end surface hardness CV value was 10%, which was good, with no yarn collapse or yarn drop on the package end surface. As a result of carrying out horizontal driving evaluation of the obtained package in the same manner as in Example 1, it was found that there was no loop dropout at an unwinding speed of 1000 m/min, and a level where only 3 drum loops fell out even at an unwinding speed of 1200 m/min, indicating a high-speed solution. The feeding was good. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was good, with a B level that showed some band-like gloss differences and ring-out defects.

[Example 6]
A drum-shaped package of polylactic acid monofilament of 30 dtex was obtained under the same conditions as in Example 1, except that the traverse swing width was changed by 4% and the amount of polymer discharged from the spinneret 5 discharge holes was changed. The package end surface hardness was 50 to 60, and the package end surface hardness CV value was 7%, which was good, with no yarn collapse or thread drop on the package end surface. The obtained package was subjected to horizontal driving evaluation in the same manner as in Example 1, and as a result, there was no loop omission at any unwinding speed, and the high-speed unwinding property was good. In addition, the quality of the fabric, which was wefted at an unwinding speed of 1200 m/min, was A level and good quality, with no difference in band-like gloss or loop defects. That is, as the weaving speed increased, the package had excellent high-speed unwinding properties, high passability during weaving, and excellent quality of the gauze fabric.

[Example 7]
Same as Example 1 except that the speed difference between the second godet rolls 9 and 10 and the winding device 15 was changed to adjust the winding tension to 0.10 cN/dtex, and the amount of polymer discharged from the spinneret 5 discharge hole was changed. A drum-shaped package of polylactic acid monofilament of 30 dtex was obtained under these conditions. The package end surface hardness was 45 to 70, and the package end surface hardness CV value was 10%, which was good with no yarn collapse or thread drop on the package end surface. As a result of carrying out horizontal driving evaluation of the obtained package in the same manner as in Example 1, it was found that there was no loop dropout at an unwinding speed of 1000 m/min, and a level where only 2 drum loops fell out even at an unwinding speed of 1200 m/min, indicating a high-speed solution. The feeding was good. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was good, with a B level, with some band-like gloss differences and ring omission defects being observed.

[Comparative example 1]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 2% and the spindle deceleration speed was changed to 50 m/sec. The package end surface hardness was 32 to 66, and the package end surface hardness CV value was 16%, and although there was no thread drop at the package end surface, thread collapse occurred in areas where the package end surface hardness was low. As a result of performing horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that a large number of loop omissions occurred at 7 drums at an unwinding speed of 1000 m/min and 15 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor, with level C being such that band-like gloss differences and loop drop defects were observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative example 2]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 2% and the spindle deceleration speed was changed to 90 m/sec. The package end surface hardness was 30 to 64, and the package end surface hardness CV value was 16%, and although there was no thread drop at the package end surface, thread collapse occurred in areas where the package end surface hardness was low. As a result of carrying out the horizontal driving evaluation of the obtained package in the same manner as in Example 1, it was found that a large number of loop omissions occurred at 10 drums at an unwinding speed of 1000 m/min and 20 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor at level D, with band-shaped differences in gloss and loop defects being frequently observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative example 3]
Except that the traverse swing width was changed to 2%, the speed difference between the second Godet rolls 9 and 10 and the winding device 15 was changed to adjust the winding tension to 0.12 cN/dtex, and the spindle deceleration speed was changed to 50 m/sec. A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1. The package end surface hardness was 25 to 70, and the package end surface hardness CV value was 18%, and although there was no thread drop at the package end surface, thread collapse occurred in areas where the package end surface hardness was low. As a result of performing horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that a large number of loop omissions occurred at 10 drums at an unwinding speed of 1000 m/min and 21 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor at level D, with band-shaped differences in gloss and loop defects being frequently observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative example 4]
A drum-shaped package of polylactic acid monofilament of 30 dtex was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 8% and the amount of polymer discharged from the spinneret 5 discharge holes was changed. The package end surface hardness was 20 to 65, the package end surface hardness CV value was 21%, 55 drums of yarn fell off at the package end surface, and yarn collapse occurred in areas where the package end surface hardness was low. As a result of performing horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that a large number of loop omissions occurred at 25 drums at an unwinding speed of 1000 m/min and 45 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor at level D, with band-shaped differences in gloss and loop defects being frequently observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative example 5]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1, except that the traverse swing width was changed to 4% and the spindle deceleration speed was changed to 100 m/sec. The package end surface hardness was 32 to 65, and the package end surface hardness CV value was 17%, and although there was no thread drop at the package end surface, thread collapse occurred in areas where the package end surface hardness was low. As a result of performing horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that there were many loop dropouts at 4 drums at an unwinding speed of 1000 m/min and 9 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor, with level C being such that band-like gloss differences and loop drop defects were observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative example 6]
A drum-shaped package of polylactic acid monofilament was obtained under the same conditions as in Example 1 except that the traverse swing width was changed to 4% and the surface pressure was changed to 150 N/m. The package end surface hardness was 22 to 66, the package end surface hardness CV value was 20%, two drums of yarn fell off at the package end surface, and yarn collapse occurred in areas where the package end surface hardness was low. As a result of performing horizontal driving evaluation on the obtained package in the same manner as in Example 1, it was found that there were many loop dropouts at 14 drums at an unwinding speed of 1000 m/min and 21 drums at an unwinding speed of 1200 m/min. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor at level D, with band-shaped differences in gloss and loop defects being frequently observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

[Comparative Example 7]
A polylactic acid-based material was prepared under the same conditions as in Example 1, except that the traverse swing width was changed to 4%, the speed difference between the second godet rolls 9 and 10 and the winding device 15 was changed, and the winding tension was changed to 0.15 cN/dtex. A monofilament drum-shaped package was obtained. The package end surface hardness was 21 to 68, the package end surface hardness CV value was 20%, 3 drums of yarn fell on the package end surface, and yarn collapse occurred in areas where the package end surface hardness was low. As a result of carrying out horizontal driving evaluation of the obtained package in the same manner as in Example 1, it was found that there were many loop omissions at 13 drums at an unwinding speed of 1000 m/min and 21 drums at an unwinding speed of 1200 m/min, and there were many loops missing at high speed unwinding. It was inferior in sex. In addition, the quality of the fabric that was wefted at an unwinding speed of 1200 m/min was poor at level D, with band-shaped differences in gloss and loop defects being frequently observed intermittently. In other words, it can be seen that the package cannot cope with an increase in the weaving speed.

1: Yarn 2: Paper tube 3: Polylactic acid monofilament package 4: Spinning block 5: Spinneret 6: Oil supply device 7: First godet roll (U)
8: 1st Goderol (L)
9: Second Goderol (U)
10: Second Goderol (L)
11: Traverse device 12: Roller bail 13: Winding side spindle 14: Standby side spindle 15: Winding device

Claims (1)

In a drum-shaped package made of polylactic acid monofilament of which 95% by weight or more is composed of lactic acid monomer, the individual values of end surface hardness measured at 36 points at 10° intervals at a package winding thickness of 25 mm are in the range of 35 to 70. A drum-shaped package made of polylactic acid monofilament, characterized in that the CV value (coefficient of variation, %) is 15% or less .