JPS623250B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing false twisted yarn with special effects. More specifically, the present invention provides a method for efficiently producing a false twisted yarn that gives a silky feel to a product. Fused yarn is generally used to produce such yarns that give a silky feel to products. For example, by setting the hot plate temperature for heat fixing during false twisting to a temperature higher than the melting point of the yarn, and fusing each filament that makes up the yarn to each other, it is possible to insert the filaments in the twisting region. The twisted yarn state is fixed, and even when the yarn enters the untwisting region of the false twisting process, part or all of it is not untwisted and each filament remains fused, making it a so-called untwisted yarn. There is a way. However, in such a method, unless the hot plate temperature is strictly controlled, the characteristics of the resulting yarn (shine feel, dyeability, etc.) will vary widely.Furthermore, the hot plate temperature is high, so There were many problems such as easy staining and poor productivity. In addition, as an improvement method, a method has been proposed in which one or several filaments made of a polymer with a low melting point are mixed in and fusion is performed at a relatively low hot plate temperature, but this method reduces the possibility of fouling of the hot plate. However, the actual situation is that the above-mentioned problems in actual production have not been essentially improved. An object of the present invention is to eliminate these drawbacks and provide a method for efficiently producing a yarn having a silky feel. The structure of the present invention that achieves the above object is to simultaneously draw a polyester multifilament undrawn yarn in which filaments having a fineness of more than 10d after drawing and false twisting are mixed at a fineness ratio of 20% to 50%. This is a method of false twisting. Compared to the conventional method of false-twisting drawn yarn or the method of performing false-twisting after drawing (so-called outdraw), the method of the present invention in which false-twisting is performed at the same time as drawing. , the filament has a large deformation in cross section and can be made into a yarn with a smooth feel. That is, for a yarn with a crisp feel, it is desirable to increase the deformation of the filament cross section so that the cross section has sharp edges. This is because the sharp edge shape of the filament cross section is an important factor in giving the knitted fabric obtained using the yarn a crisp feel when held in the hand. A filament with a particularly thick fineness, that is, a filament with a particularly large fineness after drawing and false twisting.
A filament having a fineness exceeding 10d has a large cross-sectional deformation effect, and the larger the fineness after drawing, the greater the cross-sectional deformation. For example, if the filament fineness is extremely increased, even if the undrawn filament has a round cross section, the filament after drawing and false twisting can be deformed to the extent that it can be mistaken for a ribbon-like cross-sectional shape. As an example, FIG. 1 shows one thick filament of the present invention with a fineness of 25.0 d(A) after drawing and false twisting,
FIG. 2 is a cross-sectional view of a false twisted yarn with an eight-lobed cross section, which is a mixture of 15 filaments with a fineness of 3.5 d(B). As is clear from FIG. 1, the cross section of the thick filament appears ribbon-like. Therefore, from the viewpoint of the effect of imparting a feeling of shear, it is necessary to mix filaments with a fineness of more than 10 d after drawing and false twisting, preferably 13 d or more. The influence of the stretching false twisting conditions on the cross-sectional deformation of the filament is as follows. For example, the cross-sectional deformation of the filament increases as the temperature of the false-twisting hot plate increases and as the stretching ratio increases.
Although the effect of promoting cross-sectional deformation due to false twisting conditions is not so large, the preferable range is as follows:
The temperature of the false twisting hot plate is 180°C to 220°C. The appropriate stretching ratio is generally determined by the undrawn yarn used, and although it is difficult to use as an active means for promoting cross-sectional deformation, it is usually in the range of about 1.3 to 3.4 times. Further, the fineness ratio of the thick filaments to the total filament fineness must be 50% or less; if it exceeds 50%, the knitted fabric obtained using the false twisted yarn will become coarse and hard, which is not preferable. If the fineness ratio of the thick filament to the total filament fineness is less than 20%, the smooth feeling will decrease significantly.
It is necessary to set it to 20% or more, and 25% or more is preferable. Furthermore, when performing false twisting at the same time as drawing, we use a circumscribed friction false twisting device to reduce the yarn tension at the twisted part.
When T ₁ (g) is T 1 (g) and the yarn tension at the untwisted portion is T ₂ (g), particularly excellent effects can be obtained by false twisting under the condition of T ₂ /T ₁ 0.9. Generally, the processing conditions for false twisting at the same time as stretching are _{T 2} /T _{1 1.0} ;
Under conditions below , the false twisting process becomes unstable, yarn breakage occurs frequently, and T ₁ and T ₂ fluctuate sharply.
It is common for the obtained false twisted yarn to have uneven dyeing and local tight spots (small untwisted portions of about 1 to several mm in length), resulting in unsatisfactory quality.
However, when the multifilament undrawn yarn of the present invention is used, not only the tight spots are not noticeable, but also a false twisted yarn with continuous untwisted portions can be obtained. This is probably due to the fact that the filament fineness is extremely large as a multifilament undrawn yarn, in other words, filaments that are different from other filaments are mixed, making the false twisting process more unstable. progress,
As a result, it is presumed that the resulting yarn also has unusual characteristics that would not normally be considered. especially
By setting T ₂ /T ₁ to 0.9 or less, preferably 0.7 or less, it is possible to obtain a yarn that can provide a knitted fabric with a particularly strong feeling. As described above, the present invention mixes filaments of different types (filaments of extremely thick fineness),
The purpose is to greatly increase the cross-sectional deformation of the filament by false-twisting it at the same time as drawing, and to obtain yarn for knitted fabrics with a smooth feel by optimizing the false-twisting conditions. This is what we achieved. The undrawn yarn in the present invention is used under spinning conditions (e.g.
800 to 1200 m/min) and pre-orientated yarn (so-called UY) obtained by winding at higher spinning speeds (1500 m/min or higher).
POY) can be used. In particular, in the case of a filament fineness configuration as in the present invention, POY is preferable in order to reduce yarn breakage, facilitate threading, and reduce quality changes over time. A filament with a large fineness may be melt-spun simultaneously from the same spindle as a filament with a small fineness, or may be spun individually from an adjacent spindle and then wound into the same package. Furthermore, the undrawn yarns wound into separate package cages may be pulled together when being false-twisted at the same time as drawing. In particular, from the viewpoint of production costs, it is preferable to spin and wind the yarn simultaneously from the same spinneret. Next, the manufacturing method will be explained in detail using the drawings. FIG. 2 is an embodiment diagram for explaining the simultaneous stretching and false twisting method for carrying out the present invention. In FIG. 2, the undrawn yarn 2 pulled out from the undrawn yarn package 1 is connected to a first roller 3 and a second roller 7.
It is stretched and false-twisted simultaneously between the rollers 7 and 9, and then subjected to secondary heat setting between the second roller 7 and the third roller 9, and then oiled between the third roller 9 and the fourth roller 11. It shows that it is wound up by the winding device 12. In Fig. 2, 4 is a heat fixing device (hot plate) for fixing the false twist, 5 is a yarn cooling device, 6 is a false twisting device, 8 is a secondary heat treatment device, and 10 is an oil adding roller. . Any device may be used as the false twisting device 6. However, in order to achieve T ₂ /T ₁ 0.9, it is necessary to use a friction false twisting device that has a feeding effect. For example, a circumscribed friction false twisting device equipped with a friction disk as shown in Japanese Patent Application Laid-Open No. 1565/1983 is suitable. By using such a false twisting device, the yarn tension at the twisted part can be reduced during the false twisting process at the same time as drawing.
T ₁ , that is, the running yarn tension at the upper part of the false twisting device 6, and the yarn tension at the untwisting section T ₂ , that is, the running yarn tension at the upper part of the false twisting device 6.
It is possible to make it smaller than the running yarn tension at the bottom of the . Generally, this can be achieved by increasing the rotational speed of the circumscribed friction false twisting device or by reducing the distance between the friction disks assembled in stages on the rotating shaft. The friction disc is made of ceramic material or
Although any material such as polyurethane-based rubber material can be used, it is preferable to use the latter in view of the characteristics of the resulting untwisted false-twisted yarn. The secondary heat treatment may be omitted. Similarly, additional oil may be omitted depending on the purpose. As described above, the undrawn yarn 2 is a polyester multifilament made of a mixture of thick filaments having a fineness of 10 d or more after stretching and false twisting, at a fineness ratio of 20% to 50%. For example, when expressed in terms of fineness after drawing and false twisting, 13d filament is 3
A book consisting of 13 3.2d filaments may also be used (fineness ratio 13d x 3/13d x 3 + 3.2d x 13
×100=48.4%) 1 25d filament, 15 3.5d filaments
It may be made of a book (fineness ratio 32.2%), one 20d filament, two 13d filaments, or 15 3.5d filaments (fineness ratio 46.7%). Further, the cross-sectional shape of the undrawn yarn may be circular, or alternatively a three-lobed to eight-lobed cross-sectional shape. Further, it is also possible to obtain special effects other than a silky feel by using different polymers for the thick filament and the fine filament, for example, polyester polymers with different dyeability. The polyester type used in the present invention is composed of polyethylene terephthalate, polyethylene oxybenzoate, and a copolymer containing 70% or more of these repeating units. Additives such as TiO ₂ may be contained in these polymers. Examples will be described in more detail below. Example 1 Various undrawn polyethylene terephthalate yarns (POY8 leaf cross section), in which thick filament and fine filament were discharged from the same spinneret and wound at 3000 m/min, were drawn using the apparatus shown in Figure 2. At the same time, false twisting was performed. A circular knitted fabric knitted using the obtained false twisted yarn was dyed and then its smoothness (touch) was evaluated. The results are summarized in Table 1. (Main stretching false twisting conditions) First roller circumferential speed (m/min) 226.0 Second roller circumferential speed (m/min) 400.0 Length of heat fixing device (hot plate) (m) 1.5 Heat fixing device (hot plate) Temperature (°C) 200 False twisting device 3-axis external friction false twisting device (Equipped with 8 urethane rubber discs) Number of false twists (T/m) 3230-3350

[Table] Experiment Nos. 1 to 3 are examples of the present invention, Nos. 4 and 5
is a comparative example. In order to obtain a smooth feel, the fineness of the thick filament after stretching and false twisting must exceed 10 d. Example 2 Using the same spinneret with 2 holes for a thick filament and 14 holes for a fine filament, the flow rate adjusting plate at the top of the spinneret was changed to change the fineness of both filaments and winding was performed at 3000 m/min. Five types of polyethylene terephthalate undrawn yarn (POY,
Using the same apparatus and under the same conditions as in Example 1, stretching and false twisting were performed simultaneously using a 8-leaf cross section). A circular knitted fabric knitted using the obtained false twisted yarn was dyed and then evaluated. The results are summarized in Table 2.

[Table] Experiment No. 2, and 6 and 7 are examples of the present invention.
8 and 9 are comparative examples. Experiment No. 8 had a strong rough and hard feeling rather than a smooth feeling, and No. 9 was judged to be even more rough and hard. In order to obtain a desirable silky feel, the fineness ratio needs to be 50% or less. Example 3 Using undrawn yarn (total fineness 136.4 denier) corresponding to Experiment No. 2 of Example 1, stretching and false twisting were performed at the same time by changing T ₂ /T ₁ , and the resulting false twisted yarn was used. After dyeing the circular knitted fabric, evaluation was performed. The results are shown in Table 3. The simultaneous stretching and simultaneous false twisting was carried out using the same equipment and under the same conditions as in Example 1, except for T ₂ /T ₁ .

[Table] Experiment No. 16 is a comparative example. Even when filaments with thick fineness are mixed as in Experiment No. 16, it is not possible to obtain a product with a satisfactory silkiness simply by aligning the drawn yarns and performing false twisting. Experiment Nos. 10 to 15 are examples of the present invention. In particular, those that were false-twisted at the same time as stretching under the condition that T ₂ /T ₁ was 0.9 or less (Experiment Nos. 13 to 15) had a particularly strong feeling of stiffness, which is a preferable false-twisting condition. The false twisted yarns of Experiment Nos. 13 to 15 were yarns in which untwisted bundles existed. Example 4 A false twisted yarn was obtained using the same method, conditions, and equipment as in Example 2, except that the same spinneret with 1 hole for thick filaments and 15 holes for fine filaments was used. A circular knitted fabric knitted using the obtained false twisted yarn was dyed and then evaluated. The results are summarized in Table 4.

[Table] Experiment Nos. 18 and 19 are examples of the present invention, and Experiment No. 17 is a comparative example. Experiment No. 17 had a small fineness ratio of 15%, so it was not possible to obtain a smooth feeling. In order to obtain a desirable smooth feeling, the fineness ratio needs to be 20% or more.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the cross-sectional shape of the false twisted yarn according to the present invention, and FIG. 2 is a process diagram showing an example of an embodiment of the present invention. 1: Undrawn yarn package, 2: Undrawn yarn, 3:
1st roller, 4: heat fixing device, 5: cooling device,
6: False twisting device, 7: Second roller, 8: Secondary heat treatment device, 9: Third roller, 10: Adding oil roller, 1
1: Fourth roller, 12: Winding device.

Claims (1)

[Scope of Claims] 1 A polyester multifilament undrawn yarn in which thick filaments with a fineness of more than 10 d after drawing and false twisting are mixed in a fineness ratio of 20% to 50% is subjected to false twisting at the same time as drawing. A method for producing special false twisted yarn characterized by: 2 The yarn tension T ₁ (g) in the twisted part and the yarn tension T ₂ (g) in the untwisted part were tentatively calculated using a circumscribed friction false twisting device under the condition of T ₂ /T ₁ 0.9. A method for producing special false twisted yarn according to claim 1, wherein the special false twisted yarn is twisted.