JPS5911694B2 - core yarn sewing thread - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the provision of a new type of core yarn sewing thread used as a sewing thread for sewing machines, which is intended to improve functionality and quality.

In the field of sewing threads, synthetic threads have grown significantly, but with the increase in operating speed of sewing machines and the advent of automatic sewing machines, problems such as thread breakage due to heating have occurred.

As a countermeasure for this, conventional cotton sewing thread (Katan thread) may be used, but cotton sewing thread has physical properties such as strength and elongation, and weaknesses in color fastness, making it unsuitable for full-scale replacement. be.

As a new product to replace these, we have been developing core yarns several years ago, in which the long filament of synthetic fibers is used as a core, and the fibers of cotton or other vegetable fibers are wrapped around this core yarn, which has the high strength and heat resistance of synthetic fibers. Composite sewing threads that combine the advantages and characteristics of both materials, such as cotton, which has excellent properties, have appeared, and the demand for them is increasing, but their functionality and quality are still insufficient.

Common problems with such core yarns are defects caused by poor cotton coverage, defects caused by the difference in shrinkage between the core yarn and cotton and high elongation, and defects caused by inappropriate number of twists. There may be defects, etc., and these may be removed during sewing.
This may cause skipped stitches, irregular stitches, thread breakage, etc.

The present invention has been made to solve the problems with conventional core yarns of this type, and its features include long fiber filament synthetic fibers with an elongation of 15 to 22 and a heat shrinkage of 3 or less. is used as the core thread, and the total weight ratio is 25~
It is made of 50% cotton intertwined with T/M, and its twist coefficient is A (A=,,6,.

However, T/M: number of twists, Nm: metric count, core yarn + twisted yarn) in the S direction in the range of 95 to 135, and in the case of triple twist, 1.0 to 0.8 of the number of first twists. double, or 0 in the case of triple twist
．． The point is that the twist in the Z direction is 95 to 0.75 times.

The core yarn of the present invention will be described in detail below. In the present invention, the ratio of cotton covering all the long fiber filaments and synthetic fibers is 25 to 50% of the total weight ratio. The reason is that if the ratio is less than 25, the core yarn cannot be entwined sufficiently, and the core yarn is likely to be partially exposed, and this exposure is because synthetic fibers are more glossy than cotton. 5. This is because the difference in gloss between the two may cause defects in appearance, and the exposed core yarn may be fused and cut by the heat of the sewing machine needle.

Moreover, if the strength is increased to more than 50, the strength of the cotton itself is weak, which will cause a problem with the strength of the entire system, which is one of the original characteristics of core yarn.

Also, the cotton material used is NEP or tether. It is preferable to use a high quality yarn such as a high quality combed yarn with no yarn unevenness.

In addition, as for the material of the long fiber filament synthetic fiber serving as the core thread in the present invention, for example, polyester fiber, polyamide fiber, etc. may be used depending on the purpose of use, quality level, etc. of the final core yarn sewing thread. There is no problem, but the heat shrinkage rate needs to be specified.

In other words, if the heat shrinkage rate is as low as possible, it is possible to obtain an excellent appearance and quality due to the balance between synthetic fiber and cotton.

Generally, the highest temperature applied to the thread in the sewing thread manufacturing process is the dyeing process, but for 4 m long polyester yarn, the temperature is around 130°C.
Therefore, the shrinkage rate of the core yarn in this case is preferably within 3 coefficients at 130°C x 30 minutes, and if it is a polyamide fiber, it is 1
30 minutes at 00°C or less.

In the present invention, the heat shrinkage rate is limited to a coefficient of 3 or less for the reasons mentioned above, but in order to achieve a total heat shrinkage rate of 3% or less, the lower elongation of the core yarn described in By carrying out the intended stretching treatment, it is possible to obtain a low-shrinkage yarn with a heat shrinkage factor of 3 or less as well as a low elongation.

In addition, in the present invention, the elongation of the core thread is specified as 15 to 22, but in general, if the elongation of the sewing thread is too high, it will cause skipped stitches and puckering, and if the elongation is too low, it will cause stitch skipping and puckering. This results in defects in clothing and other products after sewing.

In the present invention, the above-mentioned range is set in consideration of this point, and the core yarn whose elongation has been lowered in advance is used, and a known stretching device is used to lower the elongation. Then, it is stretched so that its elongation becomes 15 to 22%.

Next, in the present invention, a core yarn made of long fiber filament synthetic fibers that meets the above-mentioned specific conditions.

When this is tied with cotton, the twist coefficient A is 95
In the case of plywood plywood twist in the S direction in the range of ~135, the number of plywood twists is 1.0 to 0.8 times the number of plywood twists, and in the case of triple twists, the same <
The upper twist in the Z direction is applied by 0.95 to 0.75 times.

This is because the sewability of the sewing thread is generally closely related to the number of twists of the sewing thread, and selecting an appropriate number of twists is an important factor. In the final twist T/M, which is important in determining the covering property, the twist coefficient A (Ai.

However, T/M is the number of twists, Nm is the metric count, and the optimum value for the core yarn + stranded yarn is 95 to 135.

Further, the upper twist is determined by the ratio to the lower twist, but it is difficult to obtain a product of sufficient quality with a lower twist of about 65 to 75, which is generally said to be conventional.

Especially in the case of core yarn sewing thread, the cotton 42 attached to the single thread
By doubling and twisting one to three yarns, it is necessary to have the effect of suppressing the shedding and movement of the cotton, and in order to prevent thread breakage due to the twist movement during sewing, it is necessary to The number of twists is slightly higher than the number of twists, and in the case of triple twists in the present invention, the number of twists is 100 to 85, that is, about 1.0 to 0.8 times the number of first twists.
In the case of triple twist, 95 to 75 East, that is, 0.95 of the number of first twists.
~0.75 times is optimal.

The twisting direction is usually the S direction for first twist and the Z direction for first twist, and the principle of sewing thread is to heat it in opposite directions, but of course this depends on the model of the sewing machine and if the first twist S direction is required. teeth,
It does not interfere with the two directions of lower twisting and the S direction of upper twisting.

The core yarn according to the present invention has the above contents, but what is the reason for the limitation of each numerical value? As a supplement and to show the basis of the specific numerical range, the results of the quality comparison test between the conventional example and the present invention are shown in Tables 1 and 2.
It is shown as a table, and the remarkable difference in appearance and quality difference based on the difference in the number of twists between the core yarn according to the present invention and the core yarn of the conventional example are shown in reference figures (■) and H using photographs in place of drawings.

That is, Table 1 is a quality comparison table based on the content of the yarn used, and the first section in the table is the core yarn of the conventional example (comparative example).
■ Section is the core yarn according to the present invention, and in the item, the condition column shows the values given to each of the core (core yarn) and skin (cotton), and the physical property column shows the core yarn obtained under the above conditions. In the quality column, the results are compared for three items: number of fuzz, sewability, and number of skipped stitches in a predetermined length, as a comparison of the quality of each core yarn.

In addition, Table 2 shows a quality comparison of the core yarn of the conventional example (comparative example) and the core yarn according to the present invention based on the skin (cotton) ratio. In other words, in the comparative example of section 1, the skin ratio, that is, the coefficient value in the total weight ratio of cotton to the core (core yarn) is
This is a comparative example that is below the lower limit of the numerical value specified in the present invention, and the comparative example in section (■) is above the upper limit of the numerical value specified in the present invention (the skin ratio of the present invention is 25 to 25 in terms of total weight ratio). 5
As shown in the conditions column, other than the difference in skin ratio, the twisting conditions and the number of yarns in one twist are exactly the same.

The physical property values show a comparison of the physical property values of the core yarns of the ■, ■, and ing.

According to the present invention shown in Tables 1 and 2.

As is clear from the comparison with the conventional example (comparative example), although the specificity of each numerical value according to the present invention is small, it has been confirmed as a result that it is optimal at the current stage.

In addition, reference figures ■ and ■ show a comparison of the quality of core yarns with different numbers of twists. The number of twists is the twist coefficient of the first twist: A130. The upper twist is 0.95 times the lower twist, and the black part a in the figure is cotton, but the cotton almost completely entangles the core threads, there is no risk of the core threads melting, and the appearance is good. It is.

On the other hand, Figure ■ shows the core yarn of the comparative example, which is the same <45
/IX2 core yarn, the twist coefficient A of the first twist is 85.

The upper twist is 0.7 times the lower twist.

In other words, since the core cone of the comparative example has a small twist coefficient,
The core thread is exposed.

In the figure, the white part is the exposed core thread part, and the black part a is cotton, which has a poor appearance and the exposed core thread part melts during sewing, causing thread breakage and skipped stitches. .

Even if there is no thread breakage, it is clear that the appearance of the thread will not match the sewn product and will reduce the product value.

Next, one specific example of the core yarn according to the present invention will be shown.

<Example (in the case of triple twist)> Polyester of 70 denier and 24 filaments was used as the core yarn, and was previously drawn at high temperature with a continuous running drawing machine, and the elongation was 14.6% at 100°C. 30 minute shrinkage (heat shrinkage rate) is 1.1.

For the core yarn selected under the conditions of 2 stages of shrinkage at 130℃ x 30 minutes,
While adding the number of first twists (S direction) of 1050T/M, all two single yarns entwined with the cotton made of sliver-like combed yarn at a ratio of 40 to the total weight are combined, and further, the number of first twists (Z direction) is Direction) Five core yarns of the present invention could be obtained by finishing at 1000 T/M (0.95 times the number of first twists).

This core yarn had a good appearance and finished quality after sewing, and its sewability was also very good.

As described above, the present invention is excellent in that it solves the problems with conventional core yarns and improves its functionality and quality.

Claims (1)

[Claims] 1. A long fiber filament synthetic fiber with an elongation of 15 to 22% and a heat shrinkage rate of within 3 degrees is used as a core yarn, and cotton is wrapped in a proportion of 25 to 50% of the total weight. T/M, its twist coefficient A (to A, 61, however, T/M: number of twists, Nn: metric count, core yarn + envelope yarn), first twist in the S direction in the range of 95 to 135, and triple twist In the case of 1.0 of the number of first twists
~0.8 times, or 0.95 to 0.75 for triple twist
A core yarn sewing thread characterized by being double twisted in the Z direction.