JPH02221433A - Sewing thread - Google Patents

Abstract

PURPOSE:To obtain a sewing thread having excellent covering property and friction strength and resistant to breakage by preparing a sheath-core yarn containing a synthetic fiber multifilament as the core and doubling a plurality of the sheath-core yarns in a specific state. CONSTITUTION:A sheath-core yarn 1 containing a synthetic fiber multifilament as a core yarn is applied with the first twist by the delivering action of a roller 3 and a twisting action caused by the rotation of a spindle 4 using the guide 7 as the twisting point. The twisted yarn is guided by a rotating flyer 5, passed through a rotary hollow shaft 8 of the flyer under application of twist, collected by a guide 8, taken up with a feed roller 9 and applied with final twist using the guide 8 as the twisting point. The orientation of the sheath yarn is made to be almost parallel to the direction of the sewing thread axis, the apparent density of the fiber is adjusted to >=0.35g/cc and the twist number of the first twist is made to be 20-60% of that of the final twist.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sewing thread with improved coverage and frictional strength.

[Prior Art] Sewing threads made of multifilaments of synthetic fibers are widely used, and it is known to cover the outer periphery of the multifilaments with natural fibers having excellent heat resistance, such as cotton.

Furthermore, an attempt has been made to cover the multifilament by providing an air heat insulating layer using short synthetic fibers in the middle part of the core thread made of the multifilament.

[Problems to be Solved by the Invention] However, these conventional core-sheath structure yarns become brittle due to frictional heat or are even cut by melting when sewing thick fabrics or high-speed sewing machines, reducing the sewing work. In addition, there have been disadvantages in that the seam strength of the sewn product is significantly impaired.

In other words, conventionally known sewing threads composed of multifilament synthetic fibers as core threads have a core-sheath structure in which the outer periphery of the filament is covered with short fibers of cotton or synthetic fibers, but the sheath threads are ply-twisted. When heated, the fibers become loose and separate from the core yarn, so they are easily affected by needle heat and have the disadvantage of breaking.

The present invention solves this problem and provides a sewing thread that has excellent coverage and frictional strength and is difficult to break.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration. That is, it is a sewing thread formed by plucking a plurality of core-sheath structural threads each having a synthetic fiber multifilament as a core thread, and the arrangement direction of the sheath threads of the core-sheath structural threads is substantially parallel to the sewing thread axis direction, and the apparent fiber content is 0. The sewing thread is characterized in that it has a weight of 35 g/cc or more and the number of first twists is in the range of 20 to 60% of the number of second twists.

The synthetic fibers used in the present invention include, for example, polyamide,
Examples include various synthetic fiber materials made of resins such as polyester, polyacrylic, or polyvinyl alcohol, but also aromatic polyamide fibers, polyethylene drawn at a high stretching ratio, polyacrylonitrile, polyvinyl alcohol, or polyester, etc. High-strength synthetic fibers made from can also be used.

The sewing thread of the present invention uses such a multifilament of synthetic fiber as a core yarn, but natural fibers, particularly cotton, and short fibers of the synthetic fibers are used as fibers of the sheath yarn that covers the core yarn. . Note that multifilaments of the synthetic fibers are preferably applied as long as they are processed yarns. Such processed yarns include, for example, ordinary crimped yarns, those subjected to fluid entanglement with air or water, and those treated with cut fluff. It is preferable because it has better covering properties than yarn.

The sewing thread of the present invention uses such a multifilament of synthetic fiber as a core thread, and twists the thread while covering its outer periphery with a silk thread made of short fiber thread or processed thread to create a plied thread having a substantially core-sheath structure. The plurality of first-twisted yarns are twisted in a direction opposite to the twisting direction of the first-twisted yarns to obtain a twisted yarn having a first twist and a second twist.

The sewing thread of the present invention needs to have an apparent fiber fullness of 0.35 g/cc or more. This apparent fiber fullness is 0.
By setting it to 35 g/cc or more, the core thread and the sheath thread can be tightly integrated and the covering properties and frictional strength can be improved.

In other words, the apparent fiber fullness is 0. Sewing threads with a weight of less than 35 g/cc are bulky, and the sheath thread that covers the core thread tends to separate and move more easily than the core thread, and when rubbed with a sewing machine guide or the eye of a sewing machine needle, the core thread can be easily removed. If exposed, it will be more susceptible to needle heat during sewing. Practically speaking, the upper limit of the apparent fiber fullness is suitably within a range of 0.65 g/cc or less.

Furthermore, in order to properly protect the core yarn, the thickness of the fibers constituting the sheath yarn is preferably 5% or more, particularly preferably 8 to 12%, of the diameter of the first twisted yarn.

If the sheath thread is thin, needle heat is easily transmitted, causing unevenness on the covered surface and exposing the core thread.

The direction in which the sheath threads of the sewing thread of the present invention are arranged is substantially parallel to the thread axis direction, that is, in a parallel or nearly parallel state, thereby reducing wear and tear on the sheath portion.

In this parallel arrangement, the number of first twists after heating the first twist is 20 to the number of final twists.
This is achieved by setting it to 60%, preferably 25 to 60%. If it is outside this range, the fiber arrangement on the surface of the sewing thread will be oblique to the direction of the twist axis, and therefore it will be easy to receive external force from the lateral direction, making it easy for the fibers to peel or break. Furthermore, the balance is lost between the torque of the first twist yarn and the torque associated with the heating of the second twist, and the sewing thread introduced into the sewing machine needle tends to twist, making it difficult to catch the sewing thread, causing skipped stitches and fuzzing, and even more. It becomes easier to cut.

The sewing thread of the present invention has a core thread and a sheath thread closely integrated, and has high covering properties and frictional strength.

An example of a method for manufacturing such sewing thread will be described next.

That is, a method is preferably applied in which a yarn having a plurality of child ply twists is used, the yarn is further passed through a ply twist forming step, and then ply twist is formed at the same time as doubling to form a composite twisted yarn. .

In this method, a yarn having a first twist with a twist coefficient in a range of 2.4 to 3.6 is used as the yarn supplied to the first twist forming step, and a core-sheath structured yarn is used as the yarn. formed by.

If the twist coefficient of the core-sheath structure yarn of the yarn with pre-twist used as the starting yarn is less than 2.4, for example, when the yarn is pulled out from the bobbin, Following fluctuations in bobbin winding tension, the sheath thread of the thread sways,
The sheath yarn covering surface becomes easily disturbed. In addition, when the twist coefficient exceeds 3.6, as in the case of conventional core-sheath structured yarns, a large number of slack fibers are likely to be produced during ply twist formation. in this way,
The twist coefficient of the starting yarn determines the covering properties of the twisted yarn formed.

In the method of forming a twisted yarn of the present invention, by using the above-mentioned raw yarn and further adjusting the number of untwisted and untwisted twists due to the final twist to a range of 60% or less, preferably 40% or less in the final twist forming step, The coating properties and frictional strength of the resulting twisted yarn can be further improved.

This adjustment of the number of twists is achieved by actively rotating the first twist yarn to adjust the number of rotations for the first twist at the time of forming the first twist. Such adjustment can be achieved by applying the composite yarn twisting method introduced in Japanese Patent Publication No. 63-31564.

This method will be explained in more detail based on the drawings.

FIG. 1 is an example of a thread twisting machine for producing the sewing thread of the present invention.

In this device, the core-sheath structured yarn 1 wound around a plurality of independently rotatable yarn feeding bobbins 2 is twisted by the feeding action of the secondary yarn feeding roller 3 and the rotation of the spindle 4.
A first twist is applied using the guide 7 as a twisting point to form a first twist. The yarn is guided to a rotating flyer 5 that is coaxial with the bobbin shaft, and passed through the rotating hollow shaft 6 of the flyer 7 while being twisted by the swirl, and then passed through a guide 8 outside the flyer. The threads are bundled together and passed through,
When the secondary yarn is taken up by the secondary yarn feeding roller 9, the guide 8 is used as the twisting point to heat the yarn and form the final twist by the feeding action of the secondary roller 3 and twisting by the rotation of the flyer 5. A method for adjusting the number of untwisted yarns of the first twisted yarn to 60% or less of the number of final twisted yarns will be explained.

That is, the core-sheath structured yarn 1 has a counterclockwise twisting direction, but the yarn supplying bobbin 2 wound with this yarn is placed in a direction of 60 twists with respect to the flyer 5 rotating clockwise. %
You can untwist by adjusting the rotation within the following range. especially,
When the yarn feeding bobbin 2 appears to be in an apparently stationary state with respect to the rotation of the flyer 5, and the flyer 5 is rotated clockwise while forming the upper twist, the number of twists untwisted from the lower twist yarn is increased. Therefore, there is no relative difference in reduction in twist shrinkage between the core yarn and the sheath yarn, and the core yarn and the sheath yarn are closely integrated, resulting in a twisted yarn with excellent coverage and frictional strength. Furthermore, soft touch properties can be imparted by untwisting a portion of the twists from the first-twisted yarn when forming the first-twisted yarn. At this time, the number of twists to be untwisted is further increased by 40%.
If the amount is kept below, a suture thread with a better balance of coverage, frictional strength, and texture can be obtained.

That is, in the present invention, there is no need to add the number of twists required in the ply twist forming process to the ply-twisted yarn in advance, and the number of twists required as the torque of the ply-twisted yarn after forming the ply-twist is equal to 20 of the number of ply twists.
It is only necessary to heat in a range corresponding to ~60%, preferably 25-60%.

Therefore, the twist shrinkage rate during the formation of the first twisted yarn is essentially smaller than that of the conventional sewing thread with a core-sheath structure, and furthermore, with the conventional sewing thread with a core-sheath structure, the number of twists equivalent to the number of top twists is unraveled from the first twist yarn. Since the yarn is twisted, there is a large relative difference in the decrease in twist shrinkage rate between the core and sheath, whereas in the sewing thread of the present invention, the number of twists untwisted from the untwisted yarn is in the range of 0 or 60% or less of the number of final twists. because there is,
It is characterized in that the relative difference in the decrease in twist shrinkage rate between the core and sheath is small.

The sewing thread of the present invention has a small twist shrinkage ratio, and has a small amount of loose fibers after ply twisting, and is also small in bulk. In addition, the apparent fiber fullness is higher than that of conventional sewing threads with a core-sheath structure, and the yarn has good thread alignment and excellent coverage and frictional strength.

In addition, when a core-sheath structure yarn using interlaced multifilament or cut fluffed yarn as the sheath yarn is used as the starting yarn, it is compared to a core-sheath structure yarn using synthetic short fibers or cotton as a sheath yarn. Because the fibers are essentially long, even if external force is applied in the lateral direction of the fibers during use, there is extremely little wear and tear due to fibers falling off, peeling, or cutting from the surface of the sewing thread, and the core thread is rarely exposed. It exhibits this characteristic.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example) The method of measuring each characteristic value in the examples is as follows.

〈Appearance of fiber content〉 The apparent fiber fullness δ is expressed by the following formula.

δ (g/cc) = (J/V) - (n D/ yr r 2) / 900000 where J: Total weight (g) of parallelly bundled sewing threads V: Apparent weight of parallelly bundled sewing threads Volume (cc) r: Radius of the bundled sewing thread D = Fineness after oil agent extraction n: Basic number contained in the bundled sewing thread Specifically, first, the total fineness of the sewing thread is 500,000 to 800,000 deniers. , on a flat plate 23 in which two slits 22 are cut at an interval of 3 mm so that a tape 21 for measuring the circumference of the sewing threads 20, each of which is arranged in parallel and bundled, can be moved freely. Then, a 50 g load 24 is applied to the tip of the tape, and the bundled sewing thread 20 is uniformly tightened from the periphery. After tightening, the position indicated on the scale plate 26 by the pointer 25 attached to the load 13 in advance is read.

Note that the scale (cm) on the scale plate and the pointer are set to O when there is nothing inside the tape.

This circumference measurement is performed once each at three locations, and the radius r of the bundled sewing thread 3 is calculated using the average value l.
Approximately calculated using the following formula.

r (cm) = (21+0.3) /2yr The apparent volume V per 2.5 cm length of the bundled sewing thread is determined by the following formula.

V (cc)=xr2X2.5 On the other hand, the weight J per 2.5 cm of the bundled sewing thread 3 is calculated from the following formula.

J (g) = [(D/9000) /100]
x2. 5 n where D = fineness after oil extraction n: basic number of twist coefficients contained in the bundled sewing thread> The interrelationship between the twist coefficient E1, the number of twists T, and the thickness (count) S of the first twisted thread is expressed by the following formula.

T=E4S However, T: Number of twists per inch S: Fine count (total of core yarn and sheath yarn) Number of twists> The left twist direction is represented by + and the right twist direction is represented by -, but the 10 mark is omitted. The starting point for + and - was the number of twists OT/m. In addition, the ratio of the number of first twists/the number of first twists is expressed as an absolute value.

Friction Strength> Using a thread-based abrasion tester (manufactured by Amann AG, West Germany), when the thread-based friction was applied under the following conditions, the number of times of friction until the sheath yarn peeled off was measured.

Stroke: 5cm Load: Fineness 115 Loading speed: 100 times/min Example 1 One multifilament of polyester synthetic fiber with a fineness of 70D, 24 filaments, and a dyeing shrinkage rate of 2.8% at 130°C. A composite yarn having a core-sheath structure was produced by arranging the wire yarn supplied as a core yarn while being drafted on a spinning machine as a sheath yarn. When producing composite yarn, the twisting direction was S1, the number of twists was 758 T/m, and the spinning count was 47.38.
(Twist coefficient = 2.8).

Next, using the device shown in Fig. 1, wind the prepared composite yarn one by one around the two yarn feeding bobbins inside the flyer and attach it, and while rotating the flyer so that the twist direction is Z, A double-twisted yarn with a set number of twists of 946 T/m was produced.

When forming the ply-twisted yarn, the number of twists to be untwisted from the ply-twisted yarn was changed in 5% increments in the range of 15% to 65%.

The prepared ply-twisted yarn was wound back onto a dyed tube at a winding density of 0.38 using soft wine goo, and then finished into sewing yarn by a known processing method.

Table 1 shows the manufacturing conditions and product characteristics of the sewing thread of the present invention.

As a comparative example, the manufacturing conditions and product characteristics of a sewing thread having a core-sheath structure according to a conventional method are also listed for Sample No. 12 in Table 1. In other words, the manufacturing difference between the sewing thread of the present invention and the conventional method is that the number of twists is 1137 T/m (twist coefficient = 4.2) when producing the thread, and when forming the upper twist thread, the core-sheath structure yarn 2 which becomes the lower twist thread is used. The books were arranged and twisted in bulk using a ring twisting machine.

Other manufacturing conditions are the same as those of the conventional method and the sewing thread of the present invention.

As a result of comparing the fineness after producing the sewing thread in the example and after extracting the oil agent,
In the range of untwisting rate of 15 to 65% associated with ply twist formation,
There is no clear difference in fineness between the levels, and all levels are 23
It was between 7 and 239D.

Furthermore, the number of ply twists was also approximately the same for each level.

Regarding the number of first twists, as the untwisting rate increases, the number of first twists decreases, and the ratio of the number of first twists after heating the second twist to the number of first twists tends to become smaller. Note that the corrected number of first twists shown in Table 1 is obtained by removing the increase in the number of twists due to the twist shrinkage associated with the formation of the first twist, and when calculating the ratio of the number of first twists after heating the first twist to the number of first twists, This corrected number of twists was used.

The apparent fiber fullness is constant within the range of an untwisting rate of 25% or less, and is 0. 44 g/cc, the value gradually decreases until the untwisting rate reaches 50%, the value decreases noticeably until the untwisting rate reaches 60%, and when the untwisting rate exceeds 60%, the apparent fiber fullness decreases rapidly. lower and become bulkier. When the untwisting rate is 60%, the apparent fiber fullness is 0.36 g/cc, which satisfies the claimed range.

On the other hand, the number of thread-system frictions until sheath yarn separation shows a similar tendency to the apparent fiber fullness, and when the untwisting rate exceeds 60%, the number of frictions decreases rapidly. The frictional strength of the sheath yarn in terms of the number of times of friction is required to be at least twice as strong as that of the conventional sewing yarn, and to satisfy this requirement, an effective range of untwisting rate of 60% or less is effective.

As explained above, the sewing thread of the example has a higher apparent fiber density and higher frictional strength than the sewing thread of the conventional method, and therefore has excellent sewing properties.

In other words, using a lockstitch sewing machine, using 65% polyester and 3% cotton.
Layer 4 sheets of 5% blended broad #40, sewing machine rotation speed 5
Continuous 10 m sewing was repeated three times at 50 rpm.

As a result, with the exception of sample No. 1 (comparative example) and No. 11 (comparative example), it was possible to sew 10 m continuously three times with good stitches without skipping stitches or thread breakage during sewing. I was able to do that. Samples No. 1 and No. 11 had poor sewing thread twist balance, and thread breakage occurred a total of three times and two times, respectively.

In other words, the ratio of the number of first twists/the number of second twists of samples No. 1, No. 1, and No. 11 is 65% and 15%, respectively, and the sewing thread loses its balance between the torque of the first twist yarn and the torque associated with the heating of the final twist. It is not desirable as such.

In addition, as a result of using the conventional sewing thread of sample No. 12 (comparative example), it was not possible to protect the core thread from needle heat, and thread breakage occurred a total of 11 times, making it impractical in terms of sewing functionality. It was scarce.

Other sewing conditions are as follows.

(1) Sewing machine needle: Singer 1955 #14 (2)
Needle thread tension = 270 ± 50 g (3) Number of stitches: 15 stitches / 3 cm Sample No. 10 of the example and sample No. 1 of the comparative example
In No. 2, the product fineness, number of twists, and ratio of first twist/first twist are almost the same, but there are differences in apparent fiber density, number of frictions, and number of thread breaks, and the sewing thread of Example is superior. was.

[Effect of the invention] The effects of the present invention are listed below.

■Since the sewing thread of the present invention has an apparent fiber fullness of 0.35 g/cc or more, it has good thread alignment, has a structure in which the core and sheath are closely integrated, and the friction strength of the sheath thread is excellent. , it prevents the core thread from melting and breaking due to needle heat during sewing, and has a remarkable effect of improving sewability. In addition, since the thread alignment is good, uniform seams can be obtained, which has the effect of enhancing the tailoring quality of sewn products.

(2) Since the number of first twists in the sewing thread of the present invention is 25 to 60% of the number of second twists, it has excellent twist balance and can perform stable sewing. In addition, the fiber arrangement on the thread surface is parallel or nearly parallel to the thread axis direction, and the sheath thread is less likely to be worn out when it comes into contact with guides in the longitudinal direction of the thread.

■The sewing thread of the present invention does not need to add in advance the number of twists opposite to the direction of ply twisting and equivalent to the number of twists in the process to the number of twists of the ply-twisted thread in preparation for ply-twisting. The number of twists of the twisted yarn is less than that of conventional sewing yarn.

As a result, the production speed of the core-sheath structured yarn, which becomes the ply-twisted yarn, is improved.
As a result, production volume can be increased and processing costs can be reduced.

■The sewing thread of the present invention can be controlled by adding or deleting some of the number of twists of the lower twist yarn when forming the upper twist, so there is a wide range of options for selecting the number of upper twists and lower twists, and it is easy to set the twisting conditions. can be,
In addition, the loss of time and materials for setting conditions is minimized.

■By setting the twist coefficient to 2.4 to 3.6, the number of twists of the first twisted yarn can be selected as desired, and it can be produced in parallel using the same spinning machine as other spun yarns. can be produced simultaneously.

[Brief explanation of the drawing]

FIG. 1 is an example of a thread twisting device for producing the sewing thread of the present invention. FIG. 2 is a vertical cross-sectional view showing an outline of a bulk height measuring device used for calculating the apparent fiber fullness. In the figure 1: Core-sheath structured yarn 2: Yarn feeding bobbin 3 Knee feed roller 4 Nissing spindle 5: Flyer 6 = Flyer hollow rotating shaft 7. :Guide secondary feed roller 20:Sewing thread 21:Tape 22Nish slit 23:Flat plate 24:Load 25:Pointer 26:Scale plate

Claims (1)

[Claims] (1) A sewing thread made by combining multiple core-sheath structural threads with synthetic fiber multifilament as the core thread, in which the arrangement direction of the sheath threads of the core-sheath structural threads is almost parallel to the sewing thread axis direction. ,
A sewing thread characterized in that the apparent fiber fullness is 0.35 g/cc or more and the number of first twists is in the range of 20 to 60% of the number of first twists.