JPS6127484B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thick-and-thin yarn made of polyester. Polyester thick-and-thin yarn, that is, polyester yarn consisting of single yarns with varying fineness, is used as a special yarn because the fabric obtained from it exhibits a unique texture, and when this fabric is dyed, it exhibits a marbled appearance. Are known. Conventionally, as a method for manufacturing polyester thick-and-thin yarn, there is a method in which the yarn tension is varied by changing the contact angle with a grooved roller or guide during spinning or drawing of the polyester yarn.
A method is known in which the ejection ratio of two components is changed when spinning a composite fiber made of the components. However, such a method requires a complicated apparatus and has poor productivity, so it is not implemented industrially. It is also known to draw undrawn polyester yarn at a low temperature and low magnification to form a thick-and-thin yarn. However, according to this method, the thick-and-thin pattern varies greatly depending on the aging of the undrawn yarn used. Furthermore, in this method, the thick-and-thin pattern varies greatly depending on the inner and outer layers of the undrawn yarn package used. Therefore, this method cannot stably produce yarn having a predetermined thick-and-thin pattern and cannot be used industrially. The present inventors investigated a method for stably producing a specified thick-and-thin yarn with high productivity without using special equipment, and found that they could melt-spun polyester and spin it under specific conditions without having to wind it up. I learned that the above objective could be achieved by taking it up and then stretching it under specific conditions, so I proposed it earlier. However, when the thick-and-thin yarn obtained by this method is subjected to false twisting or twisting processing, yarn breakage and fluffing are likely to occur, and furthermore, when subjected to alkali reduction processing, the strength of the thick part decreases and the fastness to friction deteriorates. The problem arises. Furthermore, in the thick-and-thin yarn obtained by this method, the repetition period of the thick part and the thin part increases, and the contrast between the thick part and the thin part becomes too strong, resulting in a decrease in texture and quality when made into a woven or knitted fabric. It also has the disadvantage of As a result of further studies to solve these problems, the present inventors discovered that after spinning and drawing under specific conditions, it is sufficient to re-draw the fibers under specific conditions, and thus arrived at the present invention. did. That is, the present invention melts and discharges polyester, takes it off, performs fluid entanglement treatment, and then undrawn yarn with a birefringence index (△n) of 0.05 or less without subsequently winding it. Stretching is carried out at a first stage draw ratio (DR ₁ ) that satisfies the following formula (1) at a temperature below the secondary transition point, and then re-stretched so that the total stretch ratio (DR _T ) satisfies the following formula (2). This is a method for producing thick-and-thin yarn, which is characterized by stretching. −3.5×△n+1.2≦DR ₁ ≦−13.3×△n+2.3
...(1) −6.5×△n+1.6≦DR _T ≦−30×△n+3.3 (2) However, in the above equations (1) and (2), △n is 0.05 or less. The polyester referred to in the present invention mainly refers to polyethylene terephthalate, but a part of the terephthalic acid component (usually 15 mol% or less) can be used as other dibasic acid components, such as isophthalic acid, 5-sulfoisophthalic acid, adipic acid, etc. It may also be replaced with a part or all of the ethylene glycol component having 3 to 3 carbon atoms.
10 may be replaced by an alkylene glycol, especially butylene glycol, or may be partially replaced by a polyoxyalkylene glycol such as polyoxyethylene glycol. The degree of polymerization of such polyester should be appropriately selected depending on the type of polyester and the use of the product as a thick-and-thin yarn. Normally, in the case of polyethylene terephthalate, the intrinsic viscosity [η] determined from the value measured in an o-chlorophenol solution at 35°C is 0.55~
A value of 0.7 is preferred. When melt-extruding the polyester mentioned above, there is no need to adopt any special means, and any method can be adopted, but the important thing is to perform fluid entanglement treatment, which allows each yarn to be entangled during drawing. Stretching stress is focused preferentially on points, creating a randomized thick-and-thin pattern. For drawing following spinning, any direct stretching method can be adopted, but usually an oil supply roller, a take-up roller, and a roller that also serves as a preheating supply roller are installed in this order under the spinneret, and the downstream side of this roller is A device equipped with stretching rollers is compact in terms of equipment and is advantageous in manufacturing.
The re-stretching performed after the first-stage stretching may be performed continuously without winding up after the first-stage stretching, or may be performed using another stretching device after winding. FIG. 1 is a schematic diagram showing an example of a preferable straight-drawing method in which re-stretching is performed continuously. In the figure, 1 is a spinning device, Y is a spun yarn, 2 is an oiling roller,
3 is a fluid entanglement treatment nozzle, 4 is a take-up roller that also serves as a preheating supply roller, 5 is a separate roller, 6 is a first stage stretching roller, 7 is a separate roller, 8 is a second stage stretching roller, 9 is a separate roller, 10
is a winder. The yarn Y spun from the spinning device 1 is applied with an oil agent by an oiling roller 2, and after being entangled by a fluid entangling treatment nozzle 3, it is transferred to a take-up roller 4 preheated to a drawing temperature via a separate roller 5. It is wound several times and taken off at a predetermined speed, and at the same time is preheated to a stretching temperature, and is stretched to a predetermined magnification by a downstream first-stage stretching roller 6 and a separate roller 7, and then by a second-stage stretching roller 8 and a separate roller 9. It is re-stretched and wound up on the winder 10. In this case, the second stage drawing roller 8 may be a heating roller, on which the yarn is heat-treated for a fixed length, or the roller 8 may be a stepped heating roller, on which the yarn is subjected to relaxation treatment. Good too. In the present invention, it is necessary that the birefringence index (Δn) of the undrawn yarn after being melted and discharged and taken off and before being subjected to the first drawing is 0.05 or less. If the birefringence (Δn) exceeds 0.05, the contrast between the thick and thin portions of the obtained thick-and-thin yarn will be insufficient. Birefringence (△
In order for n) to be 0.05 or less, the take-up speed, that is, the circumferential speed of the take-up roller 4, should normally be set to 3500 m/min or less. If the take-up speed is too slow, the productivity will decrease, so it is preferable to set it to 1000 m/min or more and the birefringence (Δn) to 0.01 or more. The first stage stretching temperature, ie, the preheating temperature of the take-off roller 4, should be below the secondary transition point of the polyester used. If the temperature is higher than the second-order transition point, the contrast of the thick-and-thin decreases, and the occurrence of the thick-and-thin also becomes unstable. Also, if the roller temperature is too low, this temperature will easily fluctuate depending on the ambient temperature, which will make the occurrence of the ``thick-and-thin'' unstable.
It is preferable to keep it at room temperature (usually 25°C) or above. The first stage stretching ratio (DR ₁ ) is -3.5×△n+1.2≦
It is necessary to select within a range that satisfies the following condition: DR ₁ ≦−13.3×Δn+2.3. If this first stage stretching ratio (DR ₁ ) is too low, even if the film is re-stretched later, the period between the thick and thin parts will become too long.
A yarn exhibiting a good thick and thin effect cannot be obtained. On the other hand, if the first stage stretching ratio (DR ₁ ) becomes too high, the number of thick portions becomes too small and the thick and thin effect becomes small. Furthermore, in the present invention, re-stretching is performed after the first stage stretching ratio is completed, and the re-stretching ratio is such that the total stretching ratio (DR _T ) is -6.5×△n+1.6≦DR _T ≦
Select so that it falls within the range of -30×△n+3.3. If the total draw ratio (DR _T ) is too low, yarn breakage and fluffing are likely to occur during the false twisting and twisting processes, and when alkali weight reduction processing is performed, the strength of the thick part decreases and the fastness to friction decreases. Further, as the repetition period of the thick and thin portions becomes longer, the contrast between them becomes too strong, resulting in a problem that the texture and quality of the woven or knitted fabric deteriorate. On the other hand, if the total stretching ratio (DR _T ) becomes too high, the number of thick portions decreases and the thick and thin effect disappears.
This re-stretching may be performed in two or more stages.
The re-stretching temperature can be arbitrarily selected between 20 and 200°C.If the temperature is set higher, the contrast between the thick and thin parts will be weaker, and if the temperature is lowered, the contrast will be stronger. By changing the temperature, the contrast between the thick and thin areas can be adjusted. FIG. 2 is a graph explaining the significance of equations (1) and (2) above. Here, Figure 2 A is shown in Figure 1 below.
Examples 1 to 9 (circled with a circle) and Comparative Examples 1 to 9 in the table
9 (enclosed with a △ mark), from which equation (1) can be obtained. In addition, Figure 2 (b) shows Examples 10 to 18 (circled with circles) and comparative examples in Table 1.
10 to 15 (enclosed with a △ mark) are plotted, and equation (2) can be obtained from this. The most important feature of the present invention is that the spun and entangled undrawn yarn is continuously drawn in the first stage and then re-drawn without being wound up. By continuously drawing the spun yarn in the first stage without winding it up, it is possible to completely eliminate the effects of aging on the undrawn yarn, making it possible to maintain stable thick-and-thin yarn that always has a constant shape. can be manufactured. In addition, if the first-stage drawing is directly connected to the spinning process and then re-stretched, the thick part generated in the first-stage drawing process is further divided into two or more parts, and the thick part and the thin part are divided into two or more parts. A pick-and-thin yarn with a very short repetition period can be obtained. If the undrawn yarn that has been wound up after spinning is first drawn and then redrawn, the thick part will only become thinner, and the thick part will be divided into two or more pieces as in the case of the present invention. There is no such thing. In this way, the specific birefringence (△
By continuously drawing the intertwined undrawn yarn having the structure n) at a specific temperature and magnification without winding it up, and then re-drawing it at a specific magnification, the repetition cycle of the thick and thin portions can be shortened. In this way, it is possible to obtain a stick-and-thin yarn that has an excellent stick-and-thin effect, has good workability, and does not suffer from a decrease in the strength of the stick part or a deterioration of its fastness to friction even when treated with alkali. The object of the present invention cannot be achieved without any of the above conditions. The thus obtained pick-and-thin yarn is
It may be woven or knitted as it is, or may be subjected to heat treatment, false twisting, stretching and false twisting, etc. The present invention will be further explained below with reference to Examples.
The evaluation of the SHICK-N-THIN in the Examples was carried out as follows. 1 Form of Thick and Thin The Thick and Thin yarn is knitted into a tube and dyed in hot water at 100℃ using Eastman Kodak Polyester Navy Blue as the dye. The contrast, proportion, and period of the dyed area were observed. 2 Rubbing fastness Thick-and-thin yarn was twisted at 2000T/M, woven into a jersey, relaxed in boiling water for 20 minutes, then preset at 180°C for 45 seconds, and then washed with caustic soda at a concentration of 35 g/m. Boiling in aqueous solution for 15% weight loss, followed by dyeing with Eastman Polyester Navy Blue at 110°C for 45 seconds and at 160°C.
Use the final set for 45 seconds as a sample fabric. The measurement was performed by placing a cotton cloth (Kanakin) moistened with water on top of the sample fabric and rubbing it 100 times under a load of 500g using a Gakushin friction tester (manufactured by Showa Juiki Co., Ltd.). After that, the extent to which the colored fibers that have been abraded and fallen off from the sample fabric adhere to the cotton fabric is visually judged and ranked from 1 to 5. Grade 1 indicates that a large amount of colored fibers are attached and the fastness to rubbing is poor, and Grade 5 is that in which no colored fibers are observed at all and the fastness to rubbing is good.
This indicates that as the grade increases, the abrasion fastness improves. Examples 1 to 18 and Comparative Examples 1 to 15 Polyethylene terephthalate with an intrinsic viscosity of 0.65 containing 0.3% by weight of titanium dioxide as a dissipating agent was melted and discharged at 296°C using the apparatus shown in the figure.
10 entanglements/m are applied by the injection nozzle 3,
It is wound 8 times through the take-off roller 4 which is continuously heated to 50°C without being wound up once, and preheated while being taken off at the take-up speed listed in Table 1.
The first stage stretching is performed at the magnification shown in Table 1 between the stage stretching roller 6, and then between the first stage stretching roller 6 heated to 60°C and the second stage stretching roller 8 heated to 160°C. The film was then re-stretched at the magnification shown in Table 1 and heat-treated on the second-stage stretching roller 8, and wound up as a 9 kg package of 75 denier/36 filament. The evaluation of the obtained thick and thin yarn was as shown in Table 1.

【table】

[Table] As is clear from Table 1, birefringence (△
-3.5×△n+1.2 at a temperature below the secondary transition point without winding the undrawn yarn with n) of 0.05 or less.
≦DR ₁ ≦ −13.3×△n+2.3 The first stage of stretching is carried out under the condition that the formula is satisfied, and then the total stretching ratio (DR _T ) is −13.3×△n+2.3.
The thick-and-thin yarns of Examples 1 to 18, which were drawn in the second stage to satisfy the formula 6.5×△n+1.6≦DR _T ≦−30×△n+3.3, showed little deterioration due to alkali treatment and had low friction. It has high fastness, and the repetition period of the thick and thin parts is short, providing an excellent thick and thin effect. On the other hand, the first stage draw ratio (DR ₁ ) is -3.5
Comparative Examples 2, 4, and 6, which are less than ×△n+1.2,
The repetition period of the thick part and thin part is long (that is, the number of thick parts per unit length is small), and a good pick-and-thin effect cannot be obtained. On the other hand, when the first stage stretching ratio (DR ₁ ) exceeds -13.3×Δn+2.3 (Comparisons 1, 3, and 5), the number of thick portions decreases, and the thick and thin effect becomes small. Furthermore, the total stretching ratio (DR _T ) is -6.5×△n+1.6
In Comparative Examples 11, 13, and 15, which are less than
Quality deteriorates. In addition, fuzz and yarn breakage occur more often during false twisting and twisting. Total stretching ratio (DR _T )
In Comparative Examples 10, 12, and 14 in which Δn exceeds -30×Δn+3.3, the thick portions are small and thin, resulting in poor thick and thin effects. Furthermore, the birefringence index (△
When n) exceeds 0.05 (Comparative Examples 7 to 9), the contrast between the thick portion and the thin portion becomes insufficient. Examples 19 and 20 Comparative Examples 16 and 17 A polyethylene terephthalate copolymer containing 0.3% by weight of titanium dioxide as a dissipating agent and having an intrinsic viscosity of 0.56 and copolymerized with 3 mol% of sodium 5-sulfoisophthalate was used. After melt extrusion at 295°C, entanglement of 10 pieces/m is applied, and then the device shown in the figure is taken up by a take-up roller 4 at a take-off speed of 2000 m/min, and then transferred to the first drawing roller without winding. 6. Wind it around the separate roller 7.
First stage stretching was carried out at a magnification of 1.5 times, and then the film was directly wound onto a winder 10 without winding the second stage stretching roller 8 and separate roller 9. On this occasion,
The preheating temperature (first stage stretching temperature) of the take-up roller 4 was varied as shown in Table 2. Next, the wound yarn was passed through a drawing device equipped with a heating slit heater between a heating supply roller and a drawing roller to be redrawn. At this time, the heating supply roller temperature was 65℃, the heating slit heater temperature was 180℃, the stretching ratio (second stage stretching ratio) was 1.3 times,
The total stretching ratio (DR _T ) was 1.95 times. In addition, the birefringence index (△
n) was 0.022. Table 2 shows the evaluation results of the obtained thick and thin yarn.

[Table] The secondary transition point of the polyester of this example taken at a spinning take-off speed of 2000 m/min was approximately 72°C, and the
Examples 19 and 20 where the stage stretching temperature is below the secondary transition point
Then, the repetition period of the thick part and thin part is short,
A good thick-and-thin effect is shown, but in Comparative Examples 16 and 17, where the first-stage stretching temperature is higher than the second-order transition point, the number of thick portions decreases, and the contrast of the thick-and-thin decreases. The occurrence of this will also become unstable. Comparative Example 18 In Example 19, the undrawn yarn spun at a take-up speed of 2,000 m/min was wound into a 5 kg package, and then heated for 2 days in an atmosphere at a temperature of 25°C and a temperature of 65%.
The film left for 30 days was stretched at a preheating roller temperature of 65° C. and a stretching ratio of 1.5 times, and then re-stretched under the same conditions as in Example 19. The evaluation results of the obtained thick and thin yarn were as shown in Table 3.
In Table 3, "2 days" and "30 days" indicate the cases where the undrawn yarn package was stretched after 2 days and when it was stretched after 30 days, respectively. The term "difference between the inner and outer layers of the package" means the difference in the shape of the thick-and-thin layer between the inner layer and the outer layer of the undrawn yarn package.

[Table] As the undrawn yarn ages, the shape of the thick-and-thin changes, and differences occur in the shape of the thick-and-thin between the inner and outer layers of the package, making it difficult to stably produce thick-and-thin yarn with a constant shape. Can not do it. In addition, under the same conditions that the repetition period of the thick part and the thin part is long (that is, the number of thick parts per unit length is small), the undrawn yarn is continuously drawn in the first stage without being wound once after the yarn is taken off. Example
Compared to 19, the pick-and-sink effect was significantly inferior.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram illustrating an example of an apparatus suitable for carrying out the invention. 4 is a take-up roller that also serves as a preheat supply roller, 6 is a first-stage stretching roller, and 8 is a second-stage stretching (re-stretching) roller. Figure 2 shows DR ₁ adopted in the present invention,
This is a graph explaining the significance of _DRT .

Claims (1)

[Claims] 1. Polyester is melted and discharged, subjected to fluid entanglement treatment, and then taken back, and the refractive index (△n) is 0.05.
The undrawn yarn shown below was heated at a temperature below the secondary transition point of polyester without being wound up.
A thick and dry method characterized by stretching at a first stage draw ratio (DR ₁ ) that satisfies formula (1), and then re-stretching so that the total stretch ratio (DR _T ) satisfies formula (2) below. How to make thin yarn. −3.5×△n+1.2≦DR ₁ ≦−13.3×△n+2.3
...(1) −6.5×Δn+1.6≦DR _T ≦−30×Δn+3.3 …(2) [However, in the above formulas (1) and (2), Δn is 0.05 or less. ]