JPS607731B2 - 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 polyester wound yarn that is a knitted fabric, has a special texture, and has fewer dyeing defects when dyed with a disperse dye. Conventionally, many methods have been proposed to obtain spun-like warp-wound yarns by false twisting two or more types of polyester yarns.

The purpose is to obtain a texture similar to spun yarns such as cotton, linen, or wool.The manufacturing method involves controlling the difference in twill, the difference in orientation, and the shrinkage rate of two or more types of polyester yarn. Methods have been proposed in which the difference in elongation modulus or softening point is utilized to create a core-sheath structure or to create fusion between yarns. The striped 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 obtained port-striped 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, by using yarns with larger differences in physical properties, or by using yarns with different dyeability for one yarn, the difference in dyeability of the yarn darkness can be further expanded and the heathered color can be improved. A method for obtaining a crimped yarn with a similar texture has also been proposed. However, according to the findings of the present inventors, knitted fabrics using such warp-processed yarns having a difference 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 delicate technique that requires strict process control, and slight abnormalities in conditions such as tension fluctuations or temperature fluctuations can greatly affect the finished product. There is a tendency to The crimped yarn obtained using conventional technology is composed of threads with different dyeability.
It is considered that when the above-mentioned condition fluctuations occur in the entire process from yarn production to dyeing, dyeing defects such as twill steps and zigzag lines in striped fabrics tend to appear as a result. On the other hand,
Publication No. 0-20025 discloses that a plurality of undrawn polyester yarns having at least two types of single yarn weaves and in which the difference in birefringence between the large weave yarn and the fine twill yarn is within a certain range are simultaneously drawn. A method of stretching and false twisting has been proposed.

This method uses the birefringence of the large twill yarn (△nl) and that of the fine twill yarn (△n2) so that the large twill yarn is the core and the fine twill yarn is the sheath.
The difference between (△nl-△n2) is -2×10-3-30×1
Both beams are in the range 0-3. This reduces the difference in delivery. However, this method only has the effect of reducing dyeing differences caused by differences in weave, and has the disadvantage that dyeing differences still occur when yarns with larger physical property differences are used. Since yarn is used, the texture is naturally different. Therefore, it 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 producing 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 uses a polyethylene terephthalate yarn having a birefringence of 30×10-3 than that of the yarn.
The method is to align and false-twist a highly colored modified polyester yarn whose main component is ethylene terephthalate which is copolymerized with 0.5 to 15 mol% of aliphatic dicarboxylic acid or aromatic dicarboxylic acid. Features. The polyethylene terephthalate yarn applied to the present invention is an undrawn yarn obtained by continuously spinning polyethylene terephthalate in a conventional manner, a highly oriented undrawn yarn obtained by high-speed spinning, or a completely undrawn yarn of these undrawn yarns. Examples include semi-drawn yarns that are not drawn.

The modified polyester yarn applied to the present invention is obtained by spinning a modified polyester that has a high beam color by copolymerizing polyethylene terephthalate with 0.5 to 15 mol% of aliphatic dicarboxylic acid or aromatic dicarboxylic acid using a conventional method. Examples include stretched semi-drawn yarns or drawn yarns, highly oriented undrawn yarns obtained from high-speed paper yarns, and drawn yarns obtained by stretching these yarns.

As the aliphatic dicarboxylic acid or aromatic dicarboxylic acid,
Aliphatic dicarboxylic acids and their esters such as adipic acid and azelaic acid, aromatic dicarboxylic acids and their esters such as isophthalic acid, 5-sodium sulfisophthalic acid, 2,6-naphthalene dicarboxylic acid, Poxyethoxybenzoic acid and Its ester, trimellitic acid,
Examples include polyfunctional compounds such as pyromellitic acid and bentaerythritol, but aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred because they have a high beam-enhancing effect. Among these, isophthalic acid or 5-sodium sulfisophthalic acid is more preferred since it is easily available industrially. If the amount of aliphatic dicarboxylic acid or aromatic dicarboxylic acid added is less than 0.5 mol%, the dyeing effect is small;
On the other hand, if it exceeds 15 mol%, the beam-enhancing effect is saturated, and the melting point and yarn quality of the polyester are greatly reduced.

From this point of view, the content is more preferably 1 to 12 mol%.
In the method of the present invention, the difference in birefringence between polyethylene terephthalate yarn and modified polyester yarn is 30×10-3.
It is necessary that it is above.

At 30×10-3, the difference in physical properties between the two is 4.
The crimped structures of the resulting crimped yarns become similar, making it impossible to obtain a desired texture.

Furthermore, the method of the present invention requires that the modified polyester has higher dyeability than polyethylene terephthalate.

In this case, the dyeability refers to the 7W/38 drawn yarn obtained by subjecting both of them to normal spinning and drawing processes under the same conditions. 1
．． Dispetai Blue No. 56 disperse dye 3%o
After dyeing 6 powders at 100 pm in Liang Yuan with wf, pH = 5, Yu ratio 1:30, the dye was extracted with DMF and the exhaustion rate of Liang material (%) was determined by colorimetric method. Compare in size. Usually, it is preferable that the difference in exhaustion rate between the modified polyester and the polyethylene terephthalate beam material 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 false twisting zone; for example, a normal false twister or an indraw drawing method may be used. If necessary, a highly oriented modified polyester yarn and a low oriented polyethylene terephthalate yarn obtained by changing the paper yarn conditions such as the spinning speed and the stretching conditions such as the draw ratio are fed simultaneously to a false twisting machine. There is a way to do it.

In addition, when using an out-draw drawing false twisting machine,
A method of simultaneously drawing and false twisting a highly oriented modified polyester undrawn yarn obtained by changing the spinning process and a low oriented polyethylene terephthalate undrawn yarn, or feeding a modified polyester undrawn yarn through a drawing zone to create a polyethylene terephthalate undrawn yarn. There is a method in which the drawn yarn is fed to a false twisting zone and both are simultaneously subjected to the false twisting process. Furthermore, it is of course possible to perform the false twisting process by combining other third yarns without departing from the gist 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 stretching kneading, twisting, or interweaving by entangling treatment using fluid jetting.

After the false twisting process, it is of course possible to perform an interlacing treatment or to heat the material. The conditions for false twisting are appropriately selected to obtain the desired texture. In the crimped polyester yarn obtained by the method of the present invention, the dyeing difference between the polyethylene terephthalate yarn and the modified polyester yarn constituting the yarn is very small or can be the same.
As a result, when a knitted fabric is knitted and dyed with a disperse dye, it is possible to dramatically reduce the occurrence of defective dyeing.

Furthermore, 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 A compound shown in Table 1 was added as a third component during military condensation of polyethylene terephthalate and copolymerized to obtain a modified polyester.

Next, each of the polymers was chipped, dried, and then made into a fused paper yarn, which was further drawn and heat-set to a residual elongation of 30% to obtain a drawn yarn of 7/36 f. 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 is D
It was determined by SC measurement. It can be seen from Table 1 that aliphatic dicarboxylic acids and aromatic dicarboxylic acids both have a high dyeing effect and can be suitably used as the third component used in the modified polyester.

Furthermore, by appropriately selecting the type and amount of the third component added, it is possible to select the level of dyeability over a wide range. Table 1 Example 1 Modified polyesters of Reference Examples A, B, and C and polyethylene terephthalate (G) were spun at different spinning speeds to produce 33/72 fibers having various birefringence indexes as shown in Table 3.
A highly oriented undrawn yarn was obtained.

Next, it has a lower birefringence than this (△n=9×10-3
) The yarn was aligned with ordinary polyethylene terephthalate undrawn yarn 42 (No. 72), introduced into an in-draw spindle type stretching false twisting machine, and subjected to stretching and false twisting simultaneously under the conditions shown in Table 2. The obtained crimped yarn was woven into a fabric, dyed, and examined for texture and appearance. The results are shown in Table 3.

In Table 3, texture and dyeing were evaluated based on the following criteria. Texture Dyeing defects ○ Wool-like and bulky texture No dyeing defects △ Bulky, slightly insufficient dyeing defects Few and hardly noticeable × Not wool-like, poor texture Many dyeing defects If so, experiment no. If the difference in birefringence between the two is small, as shown in No. 6, the texture of the resulting striped yarn is poor.

Experiment No. When the birefringence difference was increased as in No. 7, a good texture was obtained, but many dyeing defects occurred. However, in Experiment No. 2, a highly oriented modified polyester undrawn yarn and a low oriented polyethylene terephthalate undrawn yarn were combined using the method of the present invention. In Examples 2 to 5, 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. In the case of No. 1, there was a drawback that not only the hand was poor, but also the modified polyester side was darkly dyed, resulting in dark dyed warp lines in the fabric. Example
2 Among the drawn yarns of 79/3& obtained in the reference example, D (birefringence △n = 152 × 10-3), E (birefringence △n = 147 × 10-3) or F (birefringence △ n=1
54×10-3) or G (birefringence △n=163×10
-3) and 10 red/36 f polyethylene terephthalate drawn yarn (△n=35×10-3), tied it into a spindle-type false twister, and twisted it under the conditions shown in Table 4. Twisted.

The obtained warp-wound yarn was knitted into a circular knitted fabric, and the appearance was inspected with a blue stain. The results are shown in Table 5. In Table 5, the visual inspection was conducted using the same criteria as in Example 1. Fourth Definition - Table 5 As shown in Table 5, Experiment No. In the case of No. 11, drawn polyethylene terephthalate yarn and undrawn yarn were used, so there was a difference in dyeing between the two after the striping process, and when knitted, light-colored striped step defects occurred frequently.

Claims (1)

[Scope of Claims] 1. A polyethylene terephthalate yarn, which has a birefringence greater than that of the yarn by 30×10^-^3 or more, and contains 0.5 to 15 mol% of aliphatic dicarboxylic acid or aromatic dicarboxylic acid. A method for producing crimped polyester yarn, which comprises aligning and false-twisting highly dyeable modified polyester yarn containing copolymerized ethylene terephthalate as a main component. 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 1 to 4 aliphatic dicarboxylic acids or aromatic dicarboxylic acids
The manufacturing method according to claim 1, wherein 12 mol% of the copolymer is copolymerized. 5. The manufacturing method according to claim 1, wherein the aromatic dicarboxylic acid is isophthalic acid or 5-sodium sulfoisophthalic acid. 6. The manufacturing method according to claim 1, wherein the difference in dyeability between the modified polyester yarn and the polyethylene terephthalate yarn is 10% or more.