JPS6024207B2 - Manufacturing method of polyester crimped yarn - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing crimped polyester yarn.

More specifically, the present invention relates to a method for producing a crimped polyester yarn that is a knitted fabric, has a special texture, and has few dyeing defects when dyed with a disperse dye. Conventionally, many methods have been proposed for obtaining spun-like wound-striped yarns by pre-combusting two or more types of polyester yarns.

The purpose is to obtain the texture of spun yarn such as cotton, linen, or wool, and the manufacturing method involves differences in fineness, degree of orientation, and shrinkage rate of two or more types of polyester yarn. , methods have been proposed in which the difference in elongation modulus or the difference in softening point is used to create a core-sheath structure or to create fusion between yarns. The wound yarn obtained by this method is a material suitable for knitted fabrics having a special texture. Also, due to the difference in physical properties between the polyester yarns, the resulting crimped yarn is composed of yarns with different dyeability, and if the yarns are sufficiently blended together, a deep color can be obtained. is possible. Furthermore, the difference in dyeability between yarns can be further expanded by using yarns with larger differences in physical properties, or by using yarns with different dyeability for one yarn. A method of obtaining a heathered crimped yarn has also been proposed. However, according to the findings of the present inventors, knitted fabrics using such warp-processed yarns, which have differences in dyeability between yarns, have a serious drawback in that poor dyeing often occurs.

Originally, the method of false-twisting two or more yarns with different physical properties is a technique that requires strict process control, and even slight abnormalities in conditions such as tension fluctuations or temperature fluctuations can greatly affect the finished product. Tend. Since the crimped yarn obtained by the conventional technique is composed of yarns with different dyeability, if the above conditions are applied during the entire process from yarn manufacturing to dyeing,
As a result, it is considered that dyeing defects such as striped steps and warp lines in knitted fabrics are likely to appear. On the other hand, JP-A-52-200
Publication No. 25 discloses simultaneous stretching and false twisting of multiple end-drawn polyesters having at least two types of single yarn weaves and having a difference in birefringence between large latitude yarns and fine twill yarns within a certain range. A method has been proposed. This method is based on the difference (△n, -2×
It has been proposed to reduce the dyeing difference between the two by setting it in the range of 10-3 to 30×10-3. However, this method is only effective at reducing the dyeing difference caused by the difference in weave, and has the disadvantage that dyeing property still occurs when yarns with larger physical property differences are used. Because they use different threads, the textures are naturally different. Therefore,
This is a method with low versatility for the purpose of obtaining more different textures. In view of the shortcomings of the prior art, the present inventors have completed the present invention as a result of intensive studies on a method for manufacturing a thread with fewer dyeing defects and a striped yarn.

An object of the present invention is to provide a polyester crimped yarn that has a special texture when made into a knitted fabric and has less uneven dyeing when dyed with a disperse dye. Another object of the present invention is to provide a method for manufacturing such polyester crimped yarn industrially easily and inexpensively. The method of the present invention consists of an undrawn or semi-drawn polyethylene terephthalate yarn and a polyethylene glycol having a birefringence greater than that of the yarn by 3×10-5 or more and having a number average molecular weight of 300 to 3000 relative to the polyethylene terephthalate. It is characterized in that the modified polyester yarn containing % by weight and highly dyeable is aligned and false-twisted. The semi-drawn or semi-drawn polyethylene terephthalate yarn applied to the present invention is an undrawn yarn obtained by paper-extruding polyethylene terephthalate in a conventional manner.
Alternatively, highly oriented undrawn yarns obtained from high-speed paper yarns, or even semi-drawn yarns in which these undrawn yarns are not completely stretched, are used.

The modified polyester yarn applied to the present invention has a number average molecular weight of 300 to 3,0 with respect to polyethylene terephthalate.
00, preferably 400 to 2,000 polyethylene glycol in an amount of 1 to 1% by weight, preferably 3 to 7% by weight, which is spun in a conventional manner and then drawn, or a semi-drawn yarn or drawn yarn; Highly oriented undrawn yarn obtained by high-speed spinning, as well as drawn yarn and the like obtained by stretching this yarn, can be spun.

Polyethylene glycol may be rapidly mixed with polyethylene terephthalate before spinning, or may be copolymerized before weaving. The birefringence of polyethylene terephthalate yarn and modified polyester yarn is 30×
If it is less than 10-3, the difference in physical properties between the two is small, so the crimped structures of the resulting crimped yarns become similar, making it impossible to obtain a desired texture.

If the number average molecular weight of polyethylene glycol is less than 300, the effect of making it easy to use is small, but it must be avoided because the melting point of the polyester is greatly lowered. On the other hand, if it exceeds 3,000, the effect of making it easy to make it easy is insufficient, and it must be avoided. The quality of the yarn deteriorates significantly due to false twisting. In addition, the content of polyethylene glycol is 1
If it is less than 10% by weight, the effect of making it easier to beam is insufficient, while if it exceeds 10% by weight, the effect of making it easier to dye is saturated and the yarn quality deteriorates significantly. In the method of the present invention, it is necessary that the modified polyester has higher dyeability than polyethylene terephthalate.

Here, the dyeability refers to the C.
1. D; sparseBlue No. 56 disperse dye 3%owf, PH=5, 1:30 ratio of 100
After dyeing at qo for 60 minutes, the dye was extracted with DMF and compared in terms of the dye exhaustion rate (%) determined by a colorimetric method. Usually, it is preferable that the difference in dye exhaustion rate between the modified polyester and the polyethylene terephthalate dye is 10% or more. Naturally, it is possible to change the degree of modification of the modified polyester depending on the degree of difference in birefringence between the two, and to reduce the difference in dyeing so as to meet the purpose of the present invention. The difference in birefringence can be adjusted as described above at any time immediately before the yarn is supplied to the temporary combustion zone, for example, using a normal false twisting machine or an indraw one-type drawing false twisting machine. If this is the case, the highly oriented modified polyester yarn obtained by changing the weaving conditions such as spinning and the stretching conditions such as the stretching ratio and the low oriented polyethylene terephthalate yarn may be simultaneously fed to the false twisting machine. There is a way to thread it.

In addition, when using an outdoor row drawing false twisting machine, there is a method in which highly oriented modified polyester undrawn yarn obtained by changing the pattern speed and a low oriented polyethylene terephthalate undrawn yarn are simultaneously stretched and quenched, or modified There is a method in which undrawn polyester yarn is fed through a drawing zone, drawn polyethylene terephthalate yarn is fed into a false twisting zone, and both are simultaneously subjected to false twisting. Furthermore, it goes without saying that other yarns shown in FIG. 3 may be combined for false twisting without departing from the spirit of the method of the present invention.

Note that the method for aligning these two or more types of yarns is not limited to simple alignment, but may also be suitably used such as stretched blend weaving, plying and twisting, or blend weaving by entangling treatment using fluid jetting.

Of course, it is also possible to perform an interlacing treatment or to perform false twisting after the false twisting process. The conditions for false twisting are appropriately selected to obtain the desired texture. The polyester crimped yarn obtained by the method of the present invention has a very small or equal dyeing difference between the polyethylene terephthalate yarn and the modified polyester yarn that constitute it, so that knitted fabrics can be knitted using this, When dyeing with disperse dyes, it is possible to significantly reduce the occurrence of poorly dyed fabrics.

In addition, since the difference in the degree of orientation between the two yarns fed to the false twisting process is sufficiently large, it has the advantage of being able to produce a wide range of special textures similar to spun yarns. Hereinafter, the method of the present invention will be specifically explained with reference to Examples, but it goes without saying that the method of the present invention is not limited thereto.

Reference Example During military condensation of polyethylene terephthalate, polyethylene glycols having various number average molecular weights were added in varying amounts and polycondensed in a conventional manner to obtain modified polyesters.

Next, each polymer was made into chips and dried, and then spun at a yarn temperature of 29,500 and a spinning speed of 100 blood/min, further drawn at a draw ratio of 3.8 stitches and a stretching speed of 1,000 h/min, and heat set to form a /38 drawn yarn. Various physical properties of these drawn yarns were measured and shown in Table 1. In Table 1, the beam exhaustion rates were determined by the method described in the text. The melting point was determined by DSC measurement. In addition, the light resistance of false-twisted yarn refers to the light-fastness of the false-twisted yarn obtained using a spindle-type false-twisting machine with a heater temperature of 21,000, dyed under the dyeing conditions for the exhaustion rate above, and then irradiated with a fade meter for 2 hours. Indicates the grade of From Table 1, the number average molecular weight of the polyethylene glycol used for the modified polyester is preferably 300 or more, considering the dyeability effect and the melting point of the polyester.
It is also found that 3000 or less is preferable from the viewpoint of yarn quality after false twisting.

On the other hand, it can be seen that the addition amount is required to be 1% by weight or more in terms of the effect of making the beam easier, and it is desirable to be 1% by weight or less in terms of yarn quality after false twisting. Further, while the beam material exhaustion rate is 35% for ordinary polyethylene terephthalate K to which polyethylene glycol is not added, all modified polyesters show a value higher than this.

Moreover, by appropriately selecting the degree of modification of the modified polyester, it is possible to select the level of dyeability over a wide range. Table 1 Example 1 Modified polyesters B, C, and G as reference examples and polyethylene terephthalate K as a control were spun at different thread speeds to produce 35M/35M polyesters having various birefringences as shown in Table 3.
7 is a highly oriented undrawn yarn with a lower birefringence than this (△
n; 9×10-5) A normal polyethylene terephthalate undrawn yarn 45/72 was aligned and introduced into an in-draw spindle type drawing/false twisting machine, and subjected to drawing and false twisting under the conditions shown in Table 2. was applied.

The obtained warped yarn was woven into a fabric, dyed, and inspected for texture and appearance. The results are shown in Table 3.

In Table 3, the texture and dyeing defects are evaluated as follows. It was conducted according to Shigeru's standards. Texture: 0 dyeing defects.Ships from a high reef.No miscellaneous girls.△ Slightly insufficient bulkiness.There are few dyeing defects, so it can hardly stand on its own.

In Table 2, Table 3, and Table 5, Experiment No. If the difference in birefringence between the two is small as in No. 7, the texture of the resulting wound yarn is poor.

However, experiment no. When the birefringence difference was increased as in No. 8, a good texture was obtained, but many dyeing defects occurred. However, an experimental vessel in which highly oriented modified polyester undrawn yarn and lowly oriented polyethylene terephthalate undrawn yarn were combined using the method of the present invention. In Examples 2 to 6, a good wool-like feel was obtained, and dyeing defects were significantly reduced.

However, in Experiment No. 3, the difference in birefringence between the undrawn modified polyester yarn and the undrawn polyethylene terephthalate yarn was 30×10-3 or less. The texture of No. 1 was poor, and the modified polyester side was darkly dyed, resulting in dark dyed streaks on the fabric. Example 2 Of the 79/38 drawn yarn obtained in the reference example, B (birefringence △
n=160×10-3) or D(△n157×10-
3) or E(△n=162×10-3) or K(△n;
165×10-3) and 10 matrix/56f polyethylene terephthalate undrawn yarn (△n=35×10
-3) and feed it to a spindle-type false twister.
False twisting was performed under the conditions shown in Table 4.

The resulting compressed yarn was knitted into a round striped fabric, dyed deep blue, and subjected to visual inspection. Table 5 shows the results. In Table 5, the visual inspection was conducted using the same criteria as in Example 1. As shown in Table 4, Table 5, Experiment No. In the case of No. 12, drawn polyethylene terephthalate yarn and undrawn yarn were used, so there was a difference in dyeing between the two after crimping, and when knitted, light-colored weft step defects occurred frequently.

Claims (1)

[Scope of Claims] 1. Undrawn or semi-drawn polyethylene terephthalate yarn, which has a birefringence greater than that of the yarn by 30×10^-^3 or more, and has a number average molecular weight of 300 to 3000 relative to polyethylene terephthalate. 1 polyethylene glycol
A method for producing a crimped polyester yarn, which comprises arranging a modified polyester yarn containing up to 10% by weight to give high dyeability and subjecting it to pre-combustion processing. 2. The manufacturing method according to claim 1, wherein polyethylene terephthalate yarn is subjected to stretching and simultaneous false twisting using an undrawn yarn. 3. The manufacturing method according to claim 1, wherein the modified polyester yarn is a drawn yarn. 4 The number average molecular weight of polyethylene glycol is 400~
2000. The manufacturing method according to claim 1. 5. The manufacturing method according to claim 1, which contains 3 to 7% by weight of polyethylene glycol. 6. The manufacturing method according to claim 1, wherein the modified polyester is a copolymer of polyethylene glycol.