JPS6347803B2 - - 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. Also known is a method of forming a thick-and-thin yarn by stretching undrawn polyester yarn at an appropriate ratio and temperature. 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 with a predetermined thick-and-thin pattern;
Cannot be used industrially. As a result of intensive research into a method for stably manufacturing a specified thick-and-thin yarn with high productivity without using special equipment, the present inventors melt-spun polyester and created a specific yarn without having to wind it up. I learned that the above objective could be achieved by taking it under certain conditions and then stretching it under certain conditions, so I proposed it earlier.
However, when the thick-and-thin yarn obtained by this method is subjected to false twisting or twisting, 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. In addition, it has poor dimensional stability and a high thermal shrinkage rate (boiling water shrinkage rate of 10% or more), so it has the disadvantage that the texture of the fabric becomes hard when subjected to heat treatment after being made into a fabric. Therefore, in order to solve these problems, the present inventors conducted further studies and found that after spinning and drawing under specific conditions, it is sufficient to perform heat treatment under specific conditions. Reached. That is, the present invention melts and discharges polyester.
Take off at a speed of 3500 m/min or less, then take it off at a temperature below the secondary transition point of polyester without winding it up, and use the following formula: 167/SS+1.21≦DR≦2100/SS+1.12 [In the formula, SS is taken off. Speed (m/min) and DR are stretching ratios (times). ] Stretched at a magnification that satisfies
This is a method for producing thick-and-thin yarn, which is characterized by heat treatment at a temperature of ~180°C and then winding. The polyester referred to in the present invention is mainly made of polyethylene terephthalate, but a part of the terephthalic acid component (usually 15 mol% or less) is used as a component of other dibasic acids, 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 above-mentioned polyester, it is not necessary to adopt any special means, and any method can be adopted, and any direct stretching method can be adopted for stretching subsequent to spinning, but usually , an oil supply roller, a fluid injection nozzle, a roller that also serves as a take-up roller and a preheating supply roller are installed in this order under the spinneret.
An apparatus in which a stepped hot-stretching roller is installed downstream of this roller is compact in terms of equipment and advantageous in manufacturing. FIG. 1 is a schematic diagram showing an example of a preferable direct stretching method, in which 1 is a spinning device, Y is a spun yarn,
2 is an oiling roller, 3 is a fluid injection nozzle, 4
5 is a take-up roller that also serves as a preheating roller, 5 is a separate roller, 6 is a stepped hot stretching roller, 7 is an entangling treatment nozzle, and 8 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 jet nozzle 3, it is sent to a take-up roller 4 preheated to a drawing temperature via a separate roller 5, and then passed through a separate roller 5. At the same time as it is wound and taken off at a predetermined speed, it is preheated to the stretching temperature, and the downstream stage-additional hot stretching roller 6
is stretched to a predetermined magnification, and then wound several times around a stepped heat-stretching roller 6 heated to a predetermined temperature to form a large diameter portion 6a and a small diameter portion 6b of the stretching roller 6.
heat treated under a relaxation rate based on the circumferential velocity of
Then, if necessary, the fabric is entangled by an entangling treatment nozzle 7 and wound into a winder 8. At this time, the number of entanglements provided by the fluid injection nozzle 3 is preferably in the range of 5 to 40 pieces/m. Further, by adjusting the number of confounds, it is also possible to control the pick-and-thin pattern. Note that the number of entanglements referred to here is the number of unopened fibers measured by placing yarns in water in which liquid paraffin is suspended. In addition, the take-up speed, that is, the surface speed of the take-up roller 4 is
It is necessary to keep the speed below 3500m/min. If the take-up speed is higher than 3500 m/min, the resulting yarn will have insufficient contrast between the thick and thin portions. If the take-up speed is too slow, productivity will decrease, so it is preferably 1000 m/min or more. The preheating temperature of the take-up roller 4, that is, the stretching temperature is as follows:
It 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 becomes small and the occurrence of the sick-and-thin also becomes unstable. In addition, if this temperature is set too low, this temperature will easily fluctuate depending on the ambient temperature, which will make the occurrence of thick-and-thin unstable.
It is preferable to do the above. If the stretching ratio is too low, the thick and thin portions become long, making it difficult to develop sufficient thick and thin. If the stretching ratio is increased, thick and thin will appear, but if it is increased too much, the difference between the thick and thin portions will become small. As a result of numerous experiments conducted by the present inventors, it has been determined that an appropriate stretching ratio must satisfy the above formula. In other words, the appropriate stretching ratio DR (times) differs depending on the drawing speed.
If the take-up speed is SS (m/min), it is necessary to satisfy the following formula: 167/SS+1.21≦DR≦2100/SS+1.12. This pick-up speed SS
FIG. 2 illustrates the range of appropriate stretching ratios (m/min). In addition, in the present invention, it is necessary to draw the spun yarn continuously without winding it once.
When the yarn is once wound up in the spinning process and then stretched, the shape of the thick-and-thin yarn changes over time as the yarn is drawn at the end, making it impossible to stably produce a thick-and-thin yarn with a certain shape. The thus obtained thick-and-thin yarn is subjected to heat treatment at a temperature of 140-180°C under relaxed conditions. This relaxation rate is not particularly limited, but is 5%
The following is commonly used, and 1 to 4% is particularly preferred. If the relaxation rate is too high, the orientation of the thick part will be disordered and there will be a tendency for embrittlement to occur.Furthermore, the yarn will become slack on the drawing and heat treatment equipment, making it difficult to draw it in a stable state.
There is a tendency for heat treatment to become impossible. Heat treatment during elongation or constant length causes thinning of the thick part,
The stick-and-thin effect tends to be reduced and the heat shrinkage rate also tends to increase. In addition, if the heat treatment temperature is less than 140°C, yarn breakage and fuzz will easily occur during false twisting and twisting, and the strength of the thick part will decrease due to the alkali weight reduction process, resulting in poor friction fastness. Furthermore, the boiling water shrinkage rate is still high at 10% or more, making it impossible to obtain a fabric with a good feel, making it unsuitable. on the other hand,
When the heat treatment temperature exceeds 180℃, the thick part begins to become brittle, yarn breakage and fluffing occur again during processing, and due to alkali weight reduction processing,
Furthermore, this should be avoided because it promotes embrittlement of the thick portion and significantly reduces the fastness to friction when made into a fabric. It is preferable to carry out this relaxation heat treatment using a stepped heat roller 6 as shown in FIG. 1, since it can be installed compactly, but it is not particularly limited to this. Any conventionally known relaxation heat treatment method can be employed, such as a method in which a heater is provided between the two and the relaxation heat treatment is performed therebetween. In this way, only by drawing at the specific speed, then stretching at the specific temperature and magnification, and then performing relaxation heat treatment at the specific temperature, can an excellent thick and thin effect be obtained. It has good processability, and even when treated with alkali, there is no decrease in the strength of the thick part or deterioration of fastness to friction, and it is possible to obtain a thick-and-thin yarn with good dimensional stability and low heat shrinkage. , the object of the present invention cannot be achieved without any of the above conditions. In FIG. 1, the entangling treatment nozzle 7 is provided downstream of the stepped hot stretching roller 6, but this is to improve the unwinding property of the yarn.
There is no problem even if it is not provided. The thus obtained pick-and-thin yarn is
It may be woven or knitted as it is, or may be subjected to heat treatment, re-stretching heat treatment, false twisting, stretching false twisting, etc. The present invention will be further explained with reference to Examples below.
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, ratio, and period between the thick areas (dark dyed areas) and thick areas (light dyed areas) 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 an aqueous solution to reduce weight by 15%, then dyeing with yeast polyester navy blue at 110°C for 45 minutes;
Use the final set at 160°C 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 using a Gakushin type friction tester (manufactured by Showa Juuki Co., Ltd.) under a load of 500 g.
After rubbing 100 times, the extent to which the colored fibers that have worn off 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 11 and Comparative Examples 1 to 6 Polyethylene terephthalate having an intrinsic viscosity of 0.65 and containing 0.3% by weight of titanium dioxide as a matting agent was prepared using the apparatus shown in FIG. 7 is not used) and 296
Melt and discharge at ℃ and spray 10 entanglements/m from injection nozzle 3.
The film is applied by a roller, set to the take-off speed and preheating roller temperature listed in Table 1, wound 8 times through the take-off roller 5, and preheated while being taken off. Therefore, while stretching at the magnification shown in Table 1, the stepwise hot stretching roller 6
It was heat treated at 160° C. with a relaxation rate of 2.0% and wound into a 9 kg package of 75 denier/36 filament. The evaluation results of the obtained thick and thin yarn were as shown in Table 1.

[Table] As is clear from the table, the spinning take-off speed is 3500
In Comparative Example 1, when the speed exceeds m/min, the contrast of the thick-and-thin is insufficient, but the spinning take-off speed is
When the speed is 3500 m/min or less (Examples 1 to 3), a good pick-and-thin configuration can be obtained. In addition, when the drawing temperature (preheating roller temperature) becomes higher than the secondary transition point (80°C) of the undrawn polyethylene terephthalate yarn spun and taken at a speed of 1800 m/min (Comparative Example 2), the The contrast becomes poor. Furthermore, when the take-up speed and the stretching ratio satisfy the relationship 167/SS+1.21≦DR≦2100/SS+1.12 (Examples 1 to 11), a good thick-and-thin form can be obtained, but the above relational expression If the above conditions are not satisfied (Comparative Examples 3 to 6), poor contrast occurs in the thick-and-thin mode. Comparative Examples 7 to 10 The same polyethylene terephthalate as used in Example 1 was melt-extruded at 296°C, taken off at the take-off speed listed in Table 2, and wound into a 5 kg undrawn yarn package at a temperature of 25°C and humidity. The samples were left in a 65% atmosphere for 2 days and 30 days, and then stretched at a preheating roller temperature of 65°C and a stretching ratio of 1.4 times. The obtained evaluation results of the Thick and Thin Yarn are the second
It was as shown in the table. In addition, “2” in Table 2
"Time after 30 days" and "Time after 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】

[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. Examples 12 to 16, Comparative Examples 11 to 13 The polyethylene terephthalate used in Example 1 was melted and discharged at 295°C using the apparatus shown in Fig. 1, and 15 entanglements/m were imparted by the injection nozzle 3. 2000℃ by the take-up roller 4 heated to 50℃.
After being taken off at a speed of m/min, the film was stretched to 1.8 times between the take-off roller 4 and the stepped hot stretching roller 6. Next, the relaxation rate at the stepped hot-stretching roller 6 and the temperature of the stepped hot-stretching roller 6 were changed as shown in Table 3, a relaxation heat treatment was performed, and the film was wound into a winder 8. Table 3 shows the evaluation results of the obtained thick and thin yarn.

【table】

[Table] In Comparative Example 11, in which the yarn was heat-treated at a constant length without relaxing it, the contrast between the thick part and the thin part was poor, the thick and thin form deteriorated, and the boiling water shrinkage rate was high. In addition, the heat treatment temperature is 140
When the temperature is outside the range of ~180°C (Comparative Examples 8 and 9), processability deteriorates and abrasion fastness decreases. Especially when the heat treatment temperature is less than 140℃ (Comparative Example 12),
The boiling water shrinkage rate is 10% or more, and fabrics using this yarn have the disadvantage of having a hard texture. On the other hand, when relaxation heat treatment was performed in the temperature range of 140 to 180°C (Examples 12 to 16), both processability and abrasion fastness were good, boiling water shrinkage was low, and the thick-and-thin yarn form was good. A good pick-and-thin yarn can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram showing an example of an apparatus suitable for carrying out the present invention, and FIG. 2 shows a spinning speed SS.
It is a chart showing the range of appropriate stretching ratio (times) with respect to (m/min). 3 is a fluid jet nozzle, 4 is a take-up roller that also serves as a preheating supply roller, and 6 is a stepped hot stretching roller.

Claims (1)

[Claims] 1. Polyester is melted and discharged and taken up at a speed of 3500 m/min or less, and then the temperature is below the secondary transition point of the polyester without being wound up once, and the following formula 167/SS+1.21≦DS ≦2100/SS+1.12 [In the formula, SS is the drawing speed (m/min) and DS is the stretching ratio (times). ] Stretched at a magnification that satisfies
A method for producing thick-and-thin yarn characterized by heat treatment at a temperature of ~180°C and then winding.