JPH0359112A - Elastic yarn for separation - Google Patents

Abstract

PURPOSE:To obtain the title elastic yarn for warper, improving productivity, having excellent performance for high-speed use by winding plural bonded multifilaments on one bobbin at specific separating stress in an arranged state. CONSTITUTION:For example, six monofilaments 13 are pulled out from a spinning chamber 1 in a mutually noncontact state and arranged in a stationary guide (e.g. made of ceramic) 7 at <=75 deg.C at <=15mg mutually separating stress of filament. The yarn is provided with a finishing oil (e.g. dimethylpolysiloxane blended with magnesium stearate dispersed) by a finishing oil roll 9 in the midst of a first godet roll 8 and a second godet roll 10 and wound to give the objective elastic yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyurethane elastic yarn that can be used while being divided in a warping machine, a covering machine, a twisting machine, a core-span spinning machine, a knitting machine, etc.

(Prior art) Polyurethane elastic yarn is generally a single bonded multifilament made by bonding multiple multifilaments coming out of the lower part of the spinning chamber with each other in an adhesive state.
Alternatively, a conventional polyurethane elastic yarn product consists of a book of monofilament wound into a single package.

Since the polyurethane elastic yarn wound in this way is a single thread wound around a single bobbin, when it is directly applied to a warping machine, core-span spinning machine, covering machine, twisting machine, or knitting machine, The number of packages required is equal to the number of threads required, and equipment such as a cradle for mounting the packages, a delivery roll, and a delivery device must be large-scale.

It is well known that several tens of inelastic filaments such as nylon or polyester fibers have been wound around a single bobbin and used for fiber separation. However, there is no example of polyurethane elastic yarn having high elasticity and adhesiveness being put into practical use as a splittable product, and the only known example is Japanese Patent Publication No. 47-17086.

According to Japanese Patent Publication No. 47-17086, since it is not possible to obtain elastic threads for splitting with good separability by the usual method of aligning and winding the threads, the threads are wound substantially in parallel using a diagonally grooved guide. A special method is used to remove For this reason, there are many restrictions on the distance between the yarns in the guide and godet rolls, making it impossible to increase the spinning speed.Parallel winders with godet rolls and friction rolls arranged in parallel cannot be used.The yarn comes off from the diagonal grooves. or,
As the number of threads passing over the oiling roll and godet roll increases, there are many problems such as an increased probability of thread breakage, and the actual situation is that this method has not been put into practical use.

In recent years, due to improved productivity in the processing field, the running speed of elastic yarn has increased significantly, sometimes exceeding 200 m/min. The mutual separability between the yarns worsens as the running speed of the elastic yarn increases, and in the prior art, it could be used at a running speed of several tens of 111 minutes, but it could not be used at a running speed exceeding 100 m/min.

(Problem R to be solved by the invention) The present invention solves the problems in terms of production and separation performance of conventional polyurethane elastic yarns for separating fibers, and provides a polyurethane elastic yarn for dividing fibers that has excellent performance even when used at high speeds. It is intended to provide a polyurethane elastic yarn.

(Means for Solving the Problem) That is, the present invention solves the mutual separation stress of a plurality of bonded multifilaments or monofilaments wound in parallel with a polyurethane elastic thread wound around a single bobbin. is 1
This is a polyurethane elastic yarn for splitting that has a particle diameter of 5 or less.

The elastic yarn used in the present invention includes so-called spandex, which is formed from fibers of which at least 85% are segmentally polymerized polyurethane.

A bonded multifilament is a multifilament in which the filaments are bonded together such that they cannot be easily separated from each other, and is a multifilament having a separation stress of 20 or more, preferably 100 or more.

In the present invention, fiber splitting refers to multiple multifilaments joined together so that they do not separate, or multiple monofilaments wound together on a single bobbin, each of which is wound back into a single multifilament or monofilament. It is.

If the separation stress is 15+g or less, preferably 10 or less, the fibers can be separated smoothly even at a running speed of 150 m/min without uneven yarn tension.

The means for reducing the separation stress to 15 .mu. or less is, for example, a method in which the yarn is forcibly cooled when it leaves the spinning chamber or after it leaves the spinning chamber. As a result of intensive studies on the relationship between the yarn temperature and the separation stress between the yarns in the method of winding the yarns by pulling them together with a stationary guide before reaching the first godet roll, we found that when the yarn temperature is 60°C or less, the yarns do not separate from each other. An elastic yarn for splitting with almost no adhesiveness and good separability, which is the aim of the invention, can be obtained.

However, the cooling rate of the yarn varies depending on the speed and denier of the yarn, and if the denier is thick or the yarn speed is fast, the yarn temperature will be cooled to 60°C or less before the first godet roll. Due to manufacturing, there is insufficient cooling zone to
Problems may occur.

For example, in the case of 70 denier and a spinning speed of 550 m/min, a cooling zone of 105 cm is required to cool the yarn temperature to below 60°C with cold air at 10"C. Generally, from the exit of the spinning chamber to the first godet roll. The distance is approximately 1 m, and cooling of the yarn must be achieved with a short cooling distance.

Furthermore, the present inventors mixed a conventionally known mold release agent into a polyurethane polymer solution and conducted various studies on yarn temperature and separation stress between yarns using the same method, and found that a trace amount of metal soap was released. By blending, the separation performance between yarns that is the aim of the present invention can be obtained at a yarn temperature of 75° C. or lower.

When the yarns are pulled together at a temperature of 75° C. or higher, a phenomenon in which the yarns adhere to each other occurs and separation stress increases. In order to lower the yarn temperature, it is advantageous to forcibly cool the yarn after it leaves the spinning chamber, to lower the length of the yarn when it leaves the spinning chamber, and to lower the yarn temperature. It is preferable to increase the flow rate.

The present invention combines the addition of metal soap to the polyurethane polymer solution and the yarn temperature when pulling the yarns together, resulting in excellent separation performance and efficient yarn separation as elastic yarn for fiber splitting. The manufacturing method can be achieved.

Polyurethane polymer? Preferred metal soaps to be added to 8i include combinations of metals such as lithium, calcium, magnesium, zinc, and aluminum and fatty acids such as lauric acid and stearic acid. The amount of metal soap to be blended is preferably 0.01% to 5%, preferably 0.03% to 0.5%, based on the weight of the polyurethane.

If it is less than this range, the separation stress between the yarns will be high and the effect as an elastic yarn for splitting will be insufficient. - On the other hand, if it exceeds the above range, although the separation stress between the yarns is excellent, it causes problems in subsequent processes such as deterioration of the physical properties of the elastic yarn, generation of scum, and deterioration of dynamic friction properties.

An example of the method for manufacturing the elastic yarn for fiber splitting of the present invention will be shown.

FIG. 1 shows a method for producing elastic yarn for splitting a bonded multifilament, in which four 3-filament bonded multifilaments are formed, and the four yarns are aligned two by two and wound around two bobbins.

A solution of polyurethane polymer containing metal soap is forced into a spinning assembly 2 attached to a spinning chamber 1 . The t8i1 is extruded from the orifice 3 of the spinneret, and is exposed to a cocurrent flow of high-temperature combustion tube@combustion gas, which is introduced into the spinning chamber through the hot air outlet 4.

The solvent of the polyurethane polymer evaporates and the continuous filament 1
3 is expressed.

The continuous filaments are twisted by a twisting machine 16 installed at the outlet of the spinning chamber, and the twisting points 14 are adjusted to be within the spinning chamber to form a bonded multifilament 15. The evaporated solvent is discharged from the hot air outlet 5 together with the high-temperature combustion gas, but in order to prevent the solvent from coming out from the hole at the bottom of the spinning chamber 1, a larger amount than the total amount of the high-temperature combustion gas and evaporated solvent that is normally introduced is discharged, and air is discharged from the lower part of the spinning chamber. flows countercurrently.

The yarn temperature of the bonded multifilament is adjusted by the amount of countercurrent air flowing from the bottom of the spinning chamber, and after the bonded multifilament leaves the spinning chamber, a cooling device 6 that blows cold air from the slit keeps the yarn temperature at 75°C. After the adjustment is made so that It is wound up as.

FIG. 2 shows a method for manufacturing an elastic yarn for monofilament splitting, in which a plurality of monofilaments are wound around one piece of cheese.

FIG. 2 shows an example of a method in which six monofilaments 13 are formed, the spinning chamber 1 is pulled out in a state where the filaments do not contact each other, and the six filaments are wound onto two bobbins, three each.

When producing elastic yarn for monofilament splitting, the twisting machine at the bottom of the spinning chamber shown in FIG. 1 is not required. The filaments pulled out from the spinning chamber are aligned by a stationary guide 7 and wound up. In this case as well, the yarn temperature when the filaments are pulled together by the stationary guide 7 is 75°C, which is the same as in the bonded multifilament, in order to keep the separation stress between the filaments below 15cm.
Adjusted below.

The cooling device 6 blows out cold air at a temperature of 5 to 15°C at an amount that does not disturb the threads. If the cooling rate is fast depending on the yarn speed and denier, and the yarn temperature can be adjusted to 75°C or less only by adjusting the amount of countercurrent air from the bottom of the spinning chamber and the ambient temperature outside the spinning chamber, the cooling device 6 is not used. The present invention can also be achieved.

The stationary guide 7 is preferably a ceramic guide made of aluminum, titanium, or the like, which has low frictional resistance, and any guide that has a structure that prevents the aligned threads from coming off is sufficient.

In the present invention, the yarns aligned by the stationary guide are
An oil agent is applied between the godet roll and the second godet roll and the product is wound up.

As for the type of oil agent, dimethylpolysiloxane used in -i or dimethylpolysiloxane in which magnesium stearate is dispersed is preferable.

The measurement method used in the present invention will be explained.

The separation stress was measured using a Tensilon tensile tester manufactured by Toyo Baldwin. In the case of two bonded multifilaments or monofilaments, they are first separated in the length direction, held in the clamps of a Tensilon tester, pulled apart at a speed of 50 cm/min, and the stress required for separation is measured.

In the case of two or more bonded multifilaments or monofilaments, first separate the books by hand, hold this and the remaining group in a clamp using the method described above, and measure repeatedly until all are separated.

Figure 3 shows a schematic diagram of the separation testing device during running.

The elastic thread 12 for splitting is brought into contact with the sending roll 17, the thread is pulled out from this, the threads are separated, and the winding roll 19
This is a device for winding and rewinding the separated yarn onto the bobbin 18 that is in contact with the upper part.

A snell guide 20 is installed on the way, and the angle (θ) between the separated threads is set to 10 degrees.

Separation during running was achieved using this device at a feed rate of 15
The judgment was made under the conditions of 0 m/min and winding speed of 225 m/min.

Example 1 A dimethylacetamide solution of a polyether-based polyurethane polymer was mixed with 0.2% by weight of magnesium stearate based on the polyurethane, and after vacuum defoaming, the solution was heated to 230°C through a nozzle with 8 holes of 0.2 mm in diameter. Eight filaments of 10 denier were extruded into a spinning chamber through which combustion gas was flowed, and after cooling to the yarn temperature shown in Table 1 with a cooling device installed at the bottom of the spinning chamber, the filaments were pulled two by two using a stationary guide. A monofilament elastic yarn for splitting was obtained by winding it around four bobbins at a spinning speed of 500 m/min while adding 5% of an oil agent mainly composed of dimethylpolyoxyloxane to the yarn.

Table 1 shows the separation liquid flow of the obtained elastic yarn for fiber splitting and the number of yarn breakages that occurred when the yarn was run for IO minutes at a speed of 150 m/min using a running separation testing device.

Table 1 The elastic yarn for fiber splitting obtained by the present invention had a very small separation stress and no yarn breakage was observed even in the running separation test.

Example 2 In a dimethylacetamide solution of a polyester-based polyurethane polymer, 0%, 0.05%, 2.
After blending 0% and 6.0% calcium stearate and vacuum degassing, the yarn was extruded into a spinning chamber in which 250°C combustion gas was flowed through a nozzle with a diameter of 0.2 wa and 32 holes, and air-jet twisted yarn was created at the bottom of the spinning chamber. Four filaments were bundled and twisted using a machine to form eight 40-denier bonded multifilaments.

After exhausting 1.7 times the total amount of high-temperature combustion gas and evaporated solvent introduced from the exhaust port at the bottom of the spinning chamber and cooling the yarn with countercurrent air from the bottom of the spinning chamber, The temperature of the spliced multifilament yarns was cooled to 75°C using a cooling device installed at An elastic yarn for splitting a spliced multifilament was obtained by winding it around four bobbins at a spinning speed of 550 m/min while adding 4% to the yarn.

Table 2 shows the separation stress of the obtained elastic yarn for splitting, the number of yarn breakages that occurred when the yarn was run for 10 minutes while separating at a speed of 150 m/min, and the amount of scum generated using a running separation test device.

To measure the amount of scum generated, feed the yarn at a feed speed of 25 m/min.
It was stretched to double its original size and run, and the blade of the safety force ξ was applied at a right angle during the run, and the amount of scum accumulated on the blade was measured.

Table 2 The elastic yarn for splitting obtained according to the present invention has low separation stress, smooth separation during running, and less yarn breakage. Comparative example 4
If calcium stearate is not added, the separation stress will be high and thread breakage will occur frequently. On the other hand, Comparative Example 7, in which a large amount of calcium stearate was blended, had good separation stress and number of thread breakages, but had the disadvantage of generating a lot of scum.

(Effects of the present invention) Since the present invention allows multiple spliced multifilaments or monofilaments to be wound onto a single bobbin, it is possible to simultaneously wind several times the number of threads from a single spinning chamber and winding machine, thereby increasing productivity. significantly improves

Since a plurality of yarns can be aligned at the same time, it can be particularly advantageous for fine denier yarns of 140 deniers or less, particularly for splitting elastic yarns of 5 deniers to 70 deniers.

In addition, excellent separation performance can be obtained by combining the addition of metal soap to the polyurethane polymer solution and the yarn temperature when pulling the yarns together, making it possible to manufacture the yarn by simply pulling it together before the first godet roll. The problems of the prior art, such as the use of special guides and restrictions on complementary angle pitch, can be solved, and an elastic yarn for splitting with excellent separation performance can be obtained.

[Brief explanation of drawings]

FIG. 1: Schematic diagram of an apparatus for producing elastic yarn for splitting spliced multifilaments, FIG. 2: Schematic diagram of an apparatus for producing elastic yarn for splitting monofilaments, and FIG. 3: Schematic diagram of a two-separation test apparatus. 1... Spinning chamber, 2... Spinning assembly, 3...
Orifice, 4...Hot air inlet, 5...Hot air outlet, 6
... Cooling device, 7... Stationary guide, 8... First Godet roll, 9... Oil agent roll, 10... Second Godet roll, 11... Flixiran roll, 12...
... Elastic yarn for splitting, 13 ... Continuous filament, 14
... Twisting point, 15 ... Joined multifilament, 1
6... Twisting machine, 17... Delivery roll, 18...
・Bobbin, 19... Winding roll, 20... Snell guide.

Claims (1)

[Claims] A polyurethane elastic yarn for splitting in which the mutual separation stress of the bonded multifilaments or monofilaments is 15 mg or less, which is a polyurethane elastic thread in which a plurality of bonded multifilaments or monofilaments are aligned and wound around a single bobbin. thread.