JPS59168182A - Production of synthetic fiber sewing machine yarn - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing synthetic fiber sewing thread that has excellent sewability, particularly eliminates the problem of skipped stitches, and improves the quality of sewn products.

In recent years, synthetic fiber spun yarn sewing thread has rapidly expanded its market share due to its high strength, uniform quality, and cost advantages. It has a defect that frequently occurs, and there are many problems in terms of sewing efficiency and quality.

Conventional synthetic fiber spun sewing thread has an extremely low modulus at initial elongation compared to cotton Katan thread, and various attempts have been made to improve stitch skipping by increasing the modulus of sewing thread. ing. One of those attempts
The first method is to use high-modulus fibers obtained by stretching and heat-treating at high temperatures and high magnifications during the manufacturing stage of synthetic fibers.

Another attempt is to make a spun yarn and then subject it to fixed length or elongation heat treatment in the form of a single yarn or a plied yarn.

However, among the former methods, the method of using high modulus fibers is difficult to provide a sufficient effect because even when the fibers are spun, the electrical power increases and the effect of the constituent fiber modulus contributing to improving the sewing thread modulus becomes small. It has the disadvantage of being Furthermore, among the former methods, the method of heat treatment at an excessively high temperature has the disadvantage that the highly modulus fiber becomes brittle and hardens. On the other hand, among the latter methods, the fixed length heat treatment method is insufficient to improve the axial fiber orientation of the spun yarn, and the elongation heat treatment method does not improve the axial orientation of the constituent fibers. Uru has a high heat shrinkability and shrinks during the subsequent dyeing process, which tends to disturb the fiber orientation again.Also, when dyeing cheese, there is a difference in tension due to shrinkage between the inner and outer layers, resulting in white spots and poor yarn properties. It has disadvantages that are easy to occur.

The present inventor has conducted extensive research on the sewability of such synthetic fiber spun sewing threads, particularly on the skipped stitch phenomenon.As a result, in order to improve stitch skipping, the present inventor has determined how large and stable the loops made by the sewing machine needle during sewing can be. They found that the dominant physical property is the modulus at the time of initial elongation, which is highly dependent on the modulus of the constituent fibers as well as the structure of the sewing thread, that is, the density of the thread, and the axis orientation of the constituent fibers. 0 An object of the present invention is to provide a method for producing a synthetic fiber sewing thread that has excellent sewability and ideally improved modulus without the problem of skipped stitches.

In order to achieve this object, the present invention has the following configuration. In other words, the present invention uses 20% stable fibers.
Synthetic fiber spun yarns containing the above are subjected to elongation heat treatment in a stretched state of 2% or more and at the following elongation temperature T + (°C), and then a plurality of them are combined and twisted, or a plurality of synthetic fiber spun yarns are combined and twisted. In an elongated state of 2% or more and at the following elongation temperature T s
(°C) and further the following relaxation temperature T2 (
This is a method for producing synthetic fiber sewing thread, which is characterized by subjecting it to relaxation heat treatment in step C), followed by dyeing and applying a smoothing agent.

The present invention improves the yarn axis orientation of the constituent fibers, increases the yarn density, and changes the yarn structure by subjecting synthetic fiber spun yarn to elongation heat treatment in the state of single yarn or plied twisted yarn, and then loosening in the overfeed portion. By performing heat treatment 5- to suppress heat shrinkage and thermally stabilize the thread structure, the modulus of the sewing thread obtained is ideally maintained even after high-temperature dyeing treatment, improving sewability and especially preventing skipped stitches. This is what we are trying to achieve.

The present invention will be explained in detail below. Examples of the fibers used in the synthetic fiber sewing thread of the present invention include thermoplastic fibers such as polyester yarn, synthetic fibers such as polyamide-based and polyvinyl alcohol-based fibers, and blends or copolymerized fibers mainly made of these fibers. The yarn structure is cotton spun.

In addition to spun yarns made of 100% staple fibers spun with staple fibers or long fibers such as wool, mixed composite yarns made of multifilament yarns and stable fibers, and core yarns with a core-sheath structure. However, 1. The synthetic fiber sewing thread of the present invention must be made of a synthetic fiber spun thread containing 20% or more of cut stable fibers.

This is because when sewing under harsh sewing conditions such as high-speed sewing or thick material sewing, if less than 20% stable fibers are used, the threads are likely to break due to the effects of needle heat. This is because the compatibility deteriorates, and the stable fibers tend to move in the yarn axis direction and fall off.

Next, the synthetic fiber spun yarn containing 20% or more of staple fibers is 2% or more, preferably 2% or more, 1.
Elongation heat treatment is performed in an elongated state of 5% or less. It is preferable to perform the elongation heat treatment on the plied and twisted yarn rather than on the single yarn in terms of yarn breakage and thermal efficiency. The purpose of this elongation heat treatment is to improve the orientation of the constituent fibers in the yarn axis direction and increase the density of the synthetic fiber spun yarn, and for this purpose, the elongation state is 2.
% or more, preferably 2% or more and 15% or less. This is because if it is less than 2%, the improvement in fiber orientation in the yarn axis direction is insufficient. The elongation temperature T+('C) at this time is also important in this regard, and Tf('C) is defined as the second-order transition temperature (
'C) and Tm ('C) is the melting point ('
C), the extension temperature Tl('C) is Tf(''C)≦
T+(''C)≦rmCC)-20(''C) must be satisfied.

This is because at a temperature below Tr ('C), the yarn structure deformation due to elongation heat treatment is insufficient, and Tm (°C) -20
At temperatures exceeding ("C), the fibers harden and become brittle.
This is because it becomes vulnerable to abrasion during the consumption process of sewing thread. From this point of view, the elongation temperature T]('C) is (Tm(
-C)-90('C)) or more, (Tm('C)-
30 (''C)) or less. The elongation heat treatment may be carried out under dry heat or wet heat, but dry heat is preferable from the viewpoint of operability.

Furthermore, the yarn subjected to the elongation heat treatment in this manner is subjected to a relaxation heat treatment in an overfeed state at a relaxation temperature T2CC). The purpose of this relaxation heat treatment is to suppress the heat shrinkage rate of the elongated heat-treated yarn by heat-treating it under low tension, stabilize the yarn structure, and significantly reduce the modulus of the yarn due to heat shrinkage during the dyeing process. This is to prevent the occurrence of single-color spots due to physical property differences between the inner and outer layers of the cheese when dyeing the cheese. Therefore, as a condition for the relaxation heat treatment, it is necessary to suppress the yield & i rate without disturbing the highly oriented fiber orientation in the yarn axis direction of the elongated heat-treated yarn as much as possible. It is preferable that the material be in a state of slight tension without being exposed to heat and that it undergoes sufficient heat treatment. From the viewpoint of bending, the relaxation temperature T2 (°C
) is Tm("C)-90(℃)≦T2(℃)≦Tm(
'C) -20 (°C) must be satisfied. (Tm
(℃) -90 (If it is less than 'C months, heat fixation will be insufficient, and if it exceeds (Tm (℃) -20 ('C months), the fiber will harden and become brittle. Note that the elongation temperature T + CC)
Regarding the relationship between T2 (°C) and relaxation temperature T2 (°C), it is preferable that T2 (°C) ≧Ts ('C) in order to stabilize the yarn, and furthermore, T + ('C) should be 71 (°C) ≧ Tm ('c). -90('C
), especially when T2('C)≧T+
(°C) is preferable. In this connection, the overfeed state of the relaxation heat treatment is preferably 0 to 20%. Note that the relaxation heat treatment may be performed by either warm heat or dry heat, but dry heat is preferable from the operational point of view. 0%
If it is less than that, it will be insufficient to suppress the shrinkage rate,
If it exceeds 20%, there will be too much slack, which will cause problems in operation.

As described above, the yarn which has been chemically stabilized by these heat treatments is dyed as is in the case of plied yarn, or after plied and twisted in the case of single yarn. The dyeing processing conditions may be those normally used for dyeing the constituent fibers. Thereafter, a smoothing agent such as silicone oil is applied according to a conventional method to prevent excessive heat generation when sewing with sewing thread, and to prevent thread breakage due to wear.

In this way, according to the present invention, 1 strength is large and 7%
A stable synthetic fiber sewing thread with a large stress during elongation (f/d), a small elongation at break (%), and a small shrinkage rate has been stably produced, and this synthetic fiber sewing thread can be used for sewing. In this case, the problem of skipped stitches is solved, and because the thread properties are stable, thread breakage is drastically reduced without any change in condition during sewing, and sewing ability is dramatically improved and puckering during the consumption process is eliminated. It has a remarkable effect, such as completely solving the problem.

Example Stable fiber of polyethylene terephthalate fiber (1
, 2dx44m), three spun yarns of Mc 60/1'S (English style fine count) were aligned and twisted together in the Z direction, which is the opposite direction to the single yarn twisting, at a twist count of 880T/M. Thereafter, heat treatment was performed under primary conditions using a two-stage heat setter. The conditions for elongation heat treatment were 205°C dry heat with a 6% elongated platform, and the conditions for relaxation heat treatment were 210°C dry heat with 4% overfeed. However, the heater length for the extension heat treatment and the heater length for the relaxation heat treatment were both 2 m. The winding speed of the yarn after heat treatment was 80 m/min. The heat-treated twisted yarn was wound around cheese and dyed using a fractional dye, and then oil mainly composed of silicone was applied to produce the synthetic #&fiber sewing thread of the present invention. The sewing thread of the present invention manufactured in this manner and the conventional polyester spun sewing thread using polyester fiber, which is the most highly evaluated material for synthetic fiber spun sewing thread as comparative example 1 (either elongation heat treatment or relaxation heat treatment) ) and a polyester spun yarn sewing thread that had been subjected to one step of heat treatment at a stretching temperature of 210° C. in a stretched state of 6 inches as Comparative Example 2, and the results are shown in the table. .

However, Comparative Example 1. Comparative Example 2 had the same spinning conditions as the present invention,
They were processed under the same twisting conditions and the same dyeing conditions.

In the above table, strength, elongation at break, stress at 7% elongation, etc. were determined by drawing a strength/elongation curve using a constant speed elongation type tensile tester (manufactured by Toyo Baldwin Co., Ltd., Tensilon). Also,
Dry heat shrinkage rate (%) is 160 degrees Celsius, 2 ml of jersey silk fabric (using 50/1'8 cotton thread) o 5 layers! The evaluation was based on the number of defects that occurred when 200 sheets were sewn using Sewing Sewing (Sewing Sewing Machine 5630ON).

As is clear from the above table, the synthetic fiber sewing thread according to the present invention has excellent sewability compared to the conventional sewing thread, and the sewing performance is excellent and the seams are extremely smooth. It's clean,
The quality of the sewn product was excellent, with no puckering occurring even after iron pressing and polishing.

Patent applicant: Toyobo Co., Ltd. 13-

Claims (1)

[Claims] 1. A synthetic fiber spun yarn containing 20% or more of staple fibers is elongated to a state of elongation of 2% or more at the elongation temperature Tr ('C) below, and then a plurality of yarns are combined. twist,
Furthermore, under the overfeed condition, the following relaxation temperature T
1. A method for producing synthetic fiber sewing thread, which comprises subjecting the thread to relaxation heat treatment at 2C°C, followed by dyeing and applying a smoothing agent. 2. The method for producing synthetic fiber sewing thread according to claim 1, wherein the relaxation temperature T2 ('C) is higher than the elongation temperature TtCC). 3. A plurality of synthetic fiber spun yarns containing 20% or more of staple fibers are twisted together, and then subjected to elongation heat treatment in a state of elongation of 2 inches or more at the elongation temperature T1 (°C) below, and then in an overfeed state. Under the following relaxation temperature T2
A method for producing synthetic fiber sewing thread, which comprises subjecting it to relaxation heat treatment in ('C), followed by dyeing and applying a smoothing agent. 4. The method for producing synthetic fiber sewing thread according to claim 3, wherein the relaxation temperature T2C) is higher than the elongation temperature TI('C).