JPH04222216A - Polyurethane elastic yarn multifilament and production thereof - Google Patents

Abstract

PURPOSE:To prevent occurrence of 'cracks' caused by filament peeling during knitting of warp knitting of polyurethane elastic yarn multifilament and end breakage resulting from peeling between filaments during production of covering yarn using the elastic yarn and further to provide knit fabric of warp knitting using the elastic yarn with tenacity. CONSTITUTION:Original yarn of polyurethane elastic yarn multifilament is brought into contact with a hot roll rotating at the same peripheral speed as those of rollers 3 and 4 before the original yarn is sent to a draft zone to heat- treat the polyurethane elastic yarn multifilament at >= fiber fixing temperature without substantially changing denier of filament.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastic fiber multifilament and a method for producing the same. Specifically, the present invention relates to a polyurethane elastic fiber multifilament that does not cause yarn breakage during covering or "ground cracking" due to interfilament peeling during warp knitting, and has high tensile strength in knitted fabrics using the filament, and a method for producing the same.

0002

[Prior Art] Conventional polyurethane elastic fiber multifilament has a low peeling strength between the filaments that make up the polyurethane elastic fiber multifilament when producing covering yarn, so they run parallel to each other during yarn breakage and knitting. As a result of the filaments separated from the thread being combined with the thread running in parallel and sent, the thread with a reduced number of filaments remaining after being separated is thinner, while the thread with an increased number of filaments that has been combined becomes thicker and has a larger number of filaments. There were problems caused by poor workability, such as "cracks in the ground," which look like grooves.

[0003] In order to solve these problems, there are techniques such as applying false twist to the yarn during spinning of polyurethane elastic fiber multifilament to improve the binding power of the yarn.
Even so, the peeling strength is still insufficient at about 0.5 g, and the current situation is that poor covering yarns and yarn breakage occur due to interfilament peeling. On the other hand, in order to give tension to knitted fabrics using covering yarns such as warp knitting, the polyurethane elastic fiber multifilament during covering should have a high draft rate, but in this case too, conventional polyurethane elastic fibers Problems such as thread breakage occur with multifilament.

0004

[Problems to be Solved by the Invention] The present invention solves the problem of "ground cracking" caused by interfilament delamination during warp knitting of polyurethane elastic fiber multifilament and interfilament delamination when producing covering yarn using the elastic yarn. The object of the present invention is to provide a polyurethane elastic fiber multifilament that prevents yarn breakage and enables coating at a high draft rate, especially in the latter case, and a method for producing the same.

[0005]

[Means for Solving the Problems] That is, the present invention provides a polyurethane elastic fiber multifilament whose mutual peeling strength of the constituent filaments is 1.5 g or more, and a polyurethane elastic fiber multifilament without substantially changing its denier. This is a method for producing polyurethane elastic fiber multifilament characterized by heat treatment at a temperature equal to or higher than the fiber fixation temperature.

The polyurethane elastic fiber multifilament of the present invention has a mutual peeling strength of 1.
It is characterized by being 5g or more. As a result, the polyurethane elastic fiber multifilament of the present invention can prevent "ground cracking" during warp knitting and yarn breakage during production of covering yarn, which are caused by low interfilament peeling force.

The peel strength referred to herein can be measured by the method described below. That is, when a polyurethane elastic fiber filament yarn consists of two filaments, it is separated first in the length direction, then held in the clamp of a constant speed extension type tensile tester and pulled apart at a speed of 50 cm/min, and the force (g) required for separation is determined. If the polyurethane elastic fiber multifilament consists of 3 or more filaments, first separate one filament by hand, hold this and the remaining multiple filaments in a clamp using the above method, and measure. Measurements are taken until all groups are separated, and the average value is taken.

The polyurethane elastic fiber multifilament used in the present invention is a substantially linear polymer having hydroxyl groups at both ends and having a molecular weight of 600 to 5,000, such as polyester diol, polylactone diol, polyether diol, and polyester amide. One or more diols, polythioether diols, polyhydrocarbon diols, polycarbonate diols, polysiloxane diols, polyurethane diols, organic diisocyanates, and chain extenders having polyfunctional active hydrogen atoms, such as hydrazine, polyhydrazide, poly An elastic polymeric polymer having a urethane group in the molecule obtained by reacting semicarbazide, polyol, polyamine, hydroxylamine, water with a terminal capping agent having a monofunctional active hydrogen atom, such as a dialkylamine, in one or multiple steps. It is obtained by dry spinning, wet spinning, or melt spinning the combined material. Alternatively, a prepolymer consisting of the above-mentioned substantially cotton-like polymer having hydroxyl groups at both ends and having a molecular weight of 600 to 5,000 and an organic diisocyanate and a chain extender having a polyfunctional active hydrogen atom and a monofunctional active It is obtained by spinning while reacting with an end-capping agent having a hydrogen atom.

[0009] The polyurethane polymer composition may optionally contain organic or inorganic compounding agents having a specific chemical structure useful in known polyurethane polymer compositions, such as gas yellowing inhibitors, Adhesion of ultraviolet absorbers, antioxidants, antifungal agents, inorganic fine particles such as barium sulfate, aluminum silicate, magnesium silicate, calcium silicate, zinc oxide, calcium stearate, magnesium stearate, polytetrafluoroethylene, organopolysiloxane, etc. An inhibitor can also be added as appropriate.

[0010] Furthermore, the single yarn denier of the elastic fiber multifilament in the present invention is preferably 2.7 to 11.7 deniers, and the total denier is preferably 8 to 140 deniers, particularly for pantyhose and inner wear that require soft stretchability. A total denier of 10 to 40 deniers is preferred, and a total denier of 40 to 105 deniers is more preferred for foundations that require a good fit. Further, the elongation at break is preferably 500% or more.

Next, the method for producing a polyurethane elastic fiber multifilament of the present invention is characterized in that the polyurethane elastic fiber multifilament is heat-treated at a temperature higher than the fiber fixing temperature without substantially changing the denier without stretching the polyurethane elastic fiber multifilament. The fiber fixation temperature mentioned here is, for example,
At the temperature described in Publication No. 088, that is, when the fibers are pressed onto the surface of a heated brass block for 5 seconds using a standard brass weight weighing 200 g, the fibers adhere to the block. The temperature is determined as follows.

As a device for determining the fiber fixation temperature, a device with an electrically heatable brass block is used (for example, a Fisher-Johns melting point meter). No. 5 mm in diameter. 2 Glass rods are placed in the same plane 5 inches above the brass block and spaced approximately 8 inches apart. A standard weight made of brass and weighing 200 g is placed on the block, and the block is gradually heated to a temperature near the fixing temperature of the sample fiber. A test article approximately 18 inches long is stretched over a glass rod. Approximately 1.5 per denier
A mg weight is placed on each end of the test article and the test article is held in place. When the block reaches a temperature near the fiber fixation temperature, lift a 200 g weight and then quickly sandwich the filament test specimen between the heating block and the 200 g weight. Leave the weight as it is for 5 seconds, then lift it. If the fibers do not adhere to the block, the temperature is further increased by about 2°C and the test is repeated using a new test piece. Similar operations are repeated until the filament after removing the weight is fixed to the heating block. In the case of polyurethane fibers, the temperature is between 120°C and 20°C.
It is 0°C.

Next, FIG. 1 shows an apparatus suitable for carrying out the method for producing polyurethane elastic fiber multifilament of the present invention in the covering step and the connecting step. Although it is economical for the method of the present invention and the covering step to be continuous, they may be separate steps. Before entering the polyurethane elastic yarn multifilament 1 (original yarn) sent out from the feed rolls 3 and 4 into the draft zone 6, it is brought into contact with a hot roll 15 rotating at the same circumferential speed as the feed rolls 3 and 4 to undergo heat treatment. Further, if necessary, heat treatment can be performed by winding the film a predetermined number of times via a separate roll 16 that is not heated. The heat-treated polyurethane elastic fiber multifilament is delivered to the delivery roll 6 which rotates at the same circumferential speed as 3, 4, and 15.
, passes through a hollow spindle 8 which rotates a predetermined number of times, is covered here by a cover thread 10 and is sent to a draft roll 7. The covering thread that has passed through 7 is transferred to guide 1.
1 and is wound up as a covering yarn package 12. In this case, the cover yarn 10 and the fiber material to be knitted with the polyurethane elastic fiber multifilament of the present invention include, for example, natural fibers such as worsted, woolen, and spun cotton, and semi-synthetic fibers such as cupro and viscose rayon. Examples include woven fibers, semi-synthetic fiber filaments themselves, inelastic polymer filaments themselves, crimped yarns obtained by processing them, rovings or spun yarns of staples of inelastic polymers.

Although FIG. 1 relates to a single covered yarn covered with one covering yarn, the manufacturing method of the present invention can also be applied to a double covered yarn covered with two covered yarns. Further, a roll for oiling may be installed between the post-heat treatment roll 15 and the delivery roll 6. Here, a hot roll was used as the heating medium for heat treatment, but other contact and non-contact type furnace tube heaters, hot plates, etc. can also be used, and the material is a fiber that is sufficient to obtain the effects of the present invention. It is necessary to select a material that does not fuse with the polyurethane elastic fiber multifilament above the fixing temperature.

Next, FIG. 2 shows an apparatus suitable for carrying out the method of manufacturing the polyurethane elastic fiber multifilament of the present invention in a warping process. The polyurethane elastic fiber multifilament 22 fed from the creel 18 passes through the reed 19-a, where it is adjusted to the width of the beam, and is rotated at the same circumferential speed as the creel 18 by a nip roll 20-a, a hot roll 21, and a nip roll 20-. b, and is heat treated. Oiling is performed between the nip roll 20-b and the nip roll 20-c, and at this time the nip roll 20-c is rotated at a circumferential speed such that the draft rate necessary for oiling is preferably 1.1 to 1.2. . That is, nip roll 20
It is preferable because it rotates at a circumferential speed that is 1.1 to 1.2 times the circumferential speed of -b. Adjust the thread spacing again using the reed 19-b, and attach the beam 24.
be wound up. The draft rate of the polyurethane elastic fiber multifilament wound into the beam 24 is preferably about 1.5 as the same speed ratio as that of the creel 18.

[0016]

[Examples] The present invention will be explained in more detail in the following examples. The method of measuring the evaluation value used in the examples is shown below. <Strength (g), elongation (%), denier (d)> The polyurethane elastic fiber multifilament after heat treatment is placed between the hot roll 15 and the delivery roll 6 in Fig. 1 without covering it with other yarns. Sample strength (g), elongation (%)
) was used for measurement. Holding a sample of the polyurethane elastic fiber multifilament in a constant speed extension type tensile tester;
5 cm, the tensile speed was 50 cm/min, and the vertical axis was measured in force (g) and the horizontal axis was recorded in time (sec). From the chart obtained, breaking strength (g) and breaking elongation (%)
I asked for

Denier (d) is yarn length 90cm under no tension.
The weight (g) of the polyurethane elastic fiber multifilament yarn cut was weighed and multiplied by 10,000 to calculate the weight when the yarn length was 9,000 m. <Number of cutting weights for covering yarn> 100 polyurethane elastic fiber multifilament packages (400 g) were processed continuously for 24 hours using the 100 weight machine shown in Figure 1 using nylon 66 filament 10 denier, 7 filament as the cover yarn. The number of spindles at which thread breakage occurred was investigated. Here, the number of spindles at which thread breakage occurs =
The number of spindles in which all filaments are broken + the number of spindles in which defective covering yarn occurs.

[0018]

[Example 1] A 20-denier polyurethane elastic fiber multifilament (original yarn) consisting of 3 filaments was heat-treated under the conditions shown below, and the physical properties of the sampled yarn without drafting or covering were compared. Table 1 shows the results of measuring the number of yarn breakage after heat treatment and at various draft rates under the following conditions.

Heat treatment conditions Heat treatment (hot roll) temperature: 245°C
Heat treatment (hot roll contact) time: 0.57 seconds Yarn breakage rate measurement conditions during covering Feed roll (Fig. 1 3, 4) Circumferential speed: 3.0 (m/min) Hot roll (Fig. 1 15) Circumference Speed: 3.0 (m/min)
Delivery roll (Fig. 1 6) Circumferential speed: 3.0 (m/min) Draft roll (1st
Figure 7) Circumferential speed; 3.0 x draft rate (m
/mi
n)
Take-up roll (Fig. 1 13) Circumferential speed: 3
．． 0 x draft rate x 0.95

(m/min) Draft rate range;
4.1 for every 0.1 from 3.3

Up to Cover yarn twist count
;250
0 (times/m) Spindle rotation speed
;2500×3×draft rate (r
p
m)

[0020]

[Comparative Example 1] The number of yarn breakage during covering of the original yarn used in Example 1 was measured using the conventional covering method without heat treatment in Example 1 at various draft rates, and the results were carried out. The results are shown in Table 1 along with the results of Example 1. In addition, the physical properties of the original yarn are also shown.

As mentioned above, in Example 1, as a polyurethane elastic fiber multifilament, the elongation at break was 1.31 times that of the original yarn, and the peel strength exceeded 1 g, 3 times that of the original yarn.
．． This is an improvement of 37 times. Regarding the thread breakage rate at each draft rate, in Comparative Example 1, thread breakage gradually occurs from 3.4 times, whereas in Example 1, thread breakage does not occur up to 3.8 times, and the thread breakage rate does not occur at high draft rates. Covering was possible.

Furthermore, in Example 1, no defective covering yarn occurred.

[0023]

Example 2 A 40-denier 4-filament polyurethane elastic fiber multifilament was used as the original yarn, and warping was carried out under the conditions shown below. Number of warping conditions: 600 Creel circumferential speed: 1
32 (m/min) nip roll (20-a) peripheral speed
132 (m/min) * Hot roll circumferential speed
132 (m/min) Nip roll (20-b) peripheral speed 132 (m/min
) Nip roll (20-c) peripheral speed 158 (m/mi
n) Beam yarn surface peripheral speed 1
98 (m/min) Heat treatment conditions Hot roll temperature 245
(°C) Hot roll contact time 0.
57 (sec) *Processed by contacting each half of a hot roll with a diameter of 40 cm

[0024]

[Comparative Example 2] Warping was carried out under the same conditions as in Example 2 without heat treatment using a hot roll. Example 2 and Comparative Example 2 were knitted 1000 times under the following conditions and the number of "ground cracks" was measured. The results of Example 2 and Comparative Example 2 are summarized in Table 2.

As described above, according to the present invention, there is no occurrence of "ground cracking" caused by interfilament separation during the warp knitting process.

[0026]

[Example 3] Support pantyhose were knitted using the covering yarn covered with a draft rate of 3.8 times in Example 1 and the covering yarn covered with a draft rate of 3.5 times in Comparative Example 1. Table 3 shows the results of a wearing test conducted on 20 women with a thickness of . As shown in Table 3, the support pantyhose gave the subjects a moderate sense of tension.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Effects of the Invention] The effects of the present invention are as follows. b) By heat-treating the polyurethane elastic fiber multifilament under appropriate conditions, the elongation at break increases to 1.1 to 1.4 times the elongation at break of the base yarn, making it possible to coat with a high draft rate. , it is possible to lower the mixing ratio in the expensive polyurethane elastic fiber multifilament, increasing economic efficiency. (b) Heat treatment of polyurethane elastic fiber multifilament improves the peeling strength between the filaments, making it possible to prevent the occurrence of defective covered yarns and the occurrence of "ground cracking" in warp knitted fabrics caused by fibers between filaments.

Furthermore, the knitted fabric using the filament has high tensile strength.

[Brief explanation of the drawing]

FIG. 1 is a process schematic diagram showing an example in which the manufacturing method of the present invention is applied to a covering process.

FIG. 2 is a process schematic diagram showing an example in which the manufacturing method of the present invention is applied to a warp warping process for warp knitting.

[Explanation of symbols]

1 Polyurethane elastic fiber multifilament 2
Polyurethane elastic fiber multifilament package 3, 4 Feed roll 5 Guide 6 Delivery roll 7 Draft roll 8 Hollow spindle 9 Cover yarn package 10 Cover yarn 11 Guide 12 Governing yarn package 13 Take-up roll 14 Governing yarn 15 Hot roll 16 Separate roll 17 Polyurethane elastic fiber multifilament package 18 Creel 19-a, 19-b Reed 20-a, 20-b, 20-c Nip roll 21
Hot roll 22 Polyurethane elastic fiber multifilament 23
Oiling roll 24 beam

Claims (2)

[Claims] 1. A polyurethane elastic fiber multifilament having a peel strength of 1.5 g or more between the constituent filaments. 2. A method for producing a polyurethane elastic fiber multifilament, which comprises heat-treating the polyurethane elastic fiber multifilament at a temperature equal to or higher than the fiber fixation temperature without substantially changing its denier.