JPS6346188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing a polyester processed yarn knitted fabric that is rich in volume and easy to set.

[Prior art]

Conventionally, when polyester processed yarn is used in knitted fabrics such as flat knitted sweaters, there has been a problem with the setting properties of the knitted fabrics. In other words, flat-knit sweaters are usually knitted and linked into a product shape and then body-set using steam, but polyester cannot be set at temperatures as low as normal pressure steam, and therefore requires high-pressure setting equipment. This hindered the entry of processed polyester yarn into the sweater field. In addition, in order to solve this problem, in order to be able to set polyester processed yarn at a low temperature, we performed the wooly processing at a low temperature as much as possible to avoid giving it a strong thermal history, thereby preserving the properties of raw silk as much as possible. However, there is a way to make the setting effect appear.
In this case, the processed yarn itself has not been woolly processed at high temperatures, so it has only extremely weak crimp.
The product had the drawback of not having a good texture.

〔the purpose〕

The object of the present invention is to provide a method for manufacturing a processed yarn knitted fabric without such limitations, which allows the product (knitted fabric) to be sufficiently set using normal pressure steam while freely imparting strong crimp. There is a particular thing.

[Composition/effect]

According to the present invention, a fiber-forming polymer having polyethylene terephthalate as a main repeating unit is used.
High-speed spinning is performed at a speed of 2500 m/min or more, and the fiber is spun at a temperature higher than the crystallization temperature without being actively stretched.
Textured yarn knitting characterized by steam setting a knitted fabric made of processed yarn obtained by heat-treating for 0.02 to 1.0 seconds to achieve a crystallinity of 25% or higher and then false twisting it while stretching it. It is a method of manufacturing soil.

To further explain the present invention in detail, the material used in the present invention is preferably a fiber-forming polymer (so-called polyester) having polyethylene terephthalate as a main repeating unit. This is because, as mentioned above, when polyester is normally made into thread, it has good setting properties at high temperatures, but it has little setting properties at low temperatures, and therefore the improvement effect is great.

Next, the polymer is spun at high speed in order to facilitate crystallization of the filament in the subsequent heat treatment step. That is, if the spinning speed is low, the orientation will be low during heat treatment at a high temperature, resulting in fusion or softening phenomenon between the fibers or between the fibers and the heat treatment equipment. Therefore, the higher the spinning speed, the better, and a high spinning speed of at least 2500 m/min is required. Furthermore, this high-speed spinning increases the number of nuclei that form the basis of crystals, which means that the crystals grow and crystallize more easily in the next heating process, and from this point of view, it is more desirable that the spinning speed be 3200 m/min or higher.

Next, the spun yarn is heat treated to crystallize it. This is to pre-crystallize the molecular structure so that it does not become excessively aligned even when strong heat and tension are applied during the subsequent stretching and false-twisting process. is necessary. If the crystallinity is lower than 25%, low-temperature setting properties will be impaired when strong heat setting is applied during false twisting. And when this crystallinity is 32% or more,
It can handle any kind of false twisting without any problems. Further, in order to perform such crystallization, the spun yarn in which crystal nuclei are formed by high-speed spinning must be heated to a temperature higher than the crystallization temperature. Although the crystallization temperature depends on the heating temperature at that time, it is desirable to set it to, for example, 50°C or more, preferably 80°C or more above the secondary transition temperature of the fiber. In particular, the second order transition temperature plus
As long as the temperature is 100℃ or higher, no matter what kind of processing is applied, there will be no problem. Further, the heat treatment time requires the time required for the fiber to crystallize, and is required to be at least 0.02 seconds or more. However, if the length is too long, the fibers will become brittle and spots will occur during subsequent processing, so even if the length is too long,
The limit is 1.0 seconds, preferably 0.5 seconds or less.

The filament yarn thus obtained is subjected to a false twisting process, but at this time it is necessary to carry out stretching and false twisting. Even if you try to process the yarn in a fixed length or relaxed state, it will be difficult to process because the yarn itself has already undergone strong crystallization, and it will also become fluffy or break, and the higher the degree of crystallization, the more The shortcomings of are emphasized. On the other hand, when the raw yarn is processed while being stretched, the yarn is twisted while being stretched, so that it can be processed smoothly. The stretching ratio at this time may be determined appropriately according to the elongation of the raw yarn.
Generally, it is best to set the elongation of processed yarn to be around 12% to 30%. Further, the number of false twists and the heat treatment temperature may be the same as those for general false twisting, which is a major feature of the present invention. In other words, in the present invention, there is no need to particularly lower the heat treatment temperature to an extremely low temperature, and even if the yarn is processed within the normal false-twisting temperature range, the knitted fabric can be heated using steam (100°C), which is much lower than the temperature during false-twisting. It has an extremely amazing feature that it can be set just by spraying the following).
By taking advantage of this advantage, it is possible to make a flat knit sweater like other fibers (acrylic, wool, etc.) while taking advantage of the excellent crimp bulkiness of conventional polyester processed yarn.

In the present invention, a spindle type, a friction type, etc. may be freely used as a means for imparting false twist. Further, the processed yarn may be a so-called two-heater processed yarn, and of course this does not result in loss of setting properties. This also applies after dyeing. Furthermore, although the material used in the present invention is polyester as described above, it may also contain a so-called third component in the form of copolymerization or blending.For example, if a cationic dyeable component is added, the product can be dyed with cationic Since it can be dyed with dye, its clarity improves, making it even more suitable for flat knit sweaters. Furthermore, although the step of heat-treating and crystallizing the yarn spun at high speed may be carried out in a separate step, it is generally effective to attach a hot roller to the spinning machine and heat-treat the yarn continuously. Alternatively, as another means, a heat treatment step can be provided before the false twisting process, and the process can be performed continuously with the process. In this case, the heat treatment can be performed in a relaxed state, in a constant length, or under tension, as long as the necessary crystallization is obtained, but in general, products that are heat treated in a constant length or relaxed state have better settling properties. . However, at least active stretching must be avoided during this heat treatment.

〔effect〕

As described above, according to the present invention, the trade-off between improved crimp performance and easy setting of knitted fabrics is eliminated, and while false twisting at high temperature is adopted as in the conventional method, a high setting effect using normal pressure steam is achieved. A textured yarn knitted fabric (that is, easily set) can be provided.

Next, examples of the present invention will be shown.

Example 1 A polyethylene terephthalate homopolymer with an intrinsic viscosity of 0.64 was spun at a spinning speed of 3400 m/min.
A raw yarn of 178de/48fil was obtained. This yarn was heat-treated for 0.3 seconds while relaxing 5% with a plate heater at 180°C to achieve a crystallinity of 40%, and then false-twisted with a spindle-type false-twisting device at a number of 2200t/m, a stretching ratio of 1.25, and a set temperature of 210. Perform wooly processing at ℃,
A processed yarn of 150de/48fil was obtained. Next, the processed yarn is
After knitting into 14G jersey while aligning the material, its setability was evaluated. To evaluate the setting properties, use the knitted fabric with a metal frame.
After blowing steam at 90°C for 10 seconds in a 10% stretched state, the metal frame was removed and the rate of return was measured. If it returned completely, the set rate was 0%, and if it did not return at all, the set rate was 100%. As a result, this sample
Good setting performance was shown at 92%. In addition, the texture was excellent in the bulkiness and waist repulsion typical of processed polyester yarns.

On the other hand, when a similar knitted fabric was made by drawing and false twisting the spun yarn as usual without any particular heat treatment, the texture was excellent, but the setability was only 40%, making it a poor choice for a sweater. The frame body setting was at an impossible level. Furthermore, when the false-twisting temperature was extremely lowered to 120°C, the setting property increased to 77%, but crimp was weak and the necessary bulkiness could not be obtained.

Example 2 Polyethylene terephthalate copolymerized with 3 mol% of 5-sodium sulfoisophthalic acid
At the same time while spinning at high speed at 4200m/min
Heat treatment was performed for 0.04 seconds at a constant length using a hot roller at 220°C to obtain a raw yarn of 82de/24fil with a crystallinity of 33%.
Next, this was false-twisted using a triaxial friction false-twisting machine at a draw ratio of 1.10 and a setting temperature of 180°C to obtain a textured yarn of 75de/24fil. Next, after package dyeing this with cationic dye at normal pressure,
When we measured the setting properties of three 14G pique knitted fabrics in the same manner as above, the knitted fabric was 94%.
The knitted fabric exhibited good setting properties, and the knitted fabric had sufficient crimping, giving it a voluminous feel and a high commercial value.

As described above, according to the method of the present invention, it is possible to obtain a knitted fabric product that is easily set using a simple method such as atmospheric pressure steam while maintaining the high crimpability of the polyester processed yarn.

Claims (1)

[Claims] 1 A fiber-forming polymer whose main repeating unit is polyethylene terephthalate is spun at a speed of 2500 m/min or more, and then heat-treated for 0.02 to 1.0 seconds at a temperature higher than the crystallization temperature without active stretching to crystallize it. A knitted fabric made of textured yarn obtained by stretching and false twisting the yarn to a degree of 25% or more.
A method for producing a processed yarn knitted fabric characterized by steam setting at a temperature of 100°C or less.