JPH07216679A - Machine sewing composite thread and its production - Google Patents

Abstract

PURPOSE:To produce a machine sewing composite thread excellent in high-speed sewing properties, seam strength and heat resistance, having an arbitrary color tone and suitable for clothing or industries. CONSTITUTION:A group of polybenzazole-baged filaments (F) are fed to an electric opening machine 1 to be opened and a group of staples (S) of polyester fibers or natural fibers having >=200 deg.C melting point or kick-off temperature are fed in a ratio of 20 to 50wt.% thereto. Both the groups are blended directly before front rollers 2 to form a composite yarn and the resultant composite yarn is subjected to Z twisting treatment with a prescribed twist coefficient. Three of the composite yarns are subsequently arranged in the same direction, doubled and twisted in the direction of S twist, wound around a cheese, then dyed with a prescribed hue and treated with a lubricant composed mainly of a silicone, thus producing the objective machine sewing composite thread having >=3.5GPa breaking strength and >=150GPa initial tensile modulus.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to sewing threads. More specifically, the present invention relates to a composite sewing thread for clothing and industrial use, which has excellent sewability, has high seam strength and heat resistance even after sewing, and can be adapted to the color tone of the sewing material.

[0002]

2. Description of the Related Art Conventionally, aromatic polyamide fibers or wholly aromatic polyester fibers have been used as high-strength and heat-resistant fibers by taking advantage of the characteristics such as heat resistance and chemical resistance, and high-performance clothing such as uniforms, seat belts and safety belts. Widely used in the field of protective products such as. In recent years, general clothing having high functionality, such as sports and leisure suits, has been developed, which is made of a mixed yarn or a mixed yarn of polyester fiber or polyamide fiber and the high-strength / heat-resistant fiber. On the other hand, recently, an industrial production technology of polybenzazole fiber having high strength and heat resistance which has never been seen was developed, and with this, knitted fabrics using the fiber as a raw material have begun to be used in the above application fields. Came. In this case, in order to satisfy the sewability under severe sewing conditions and the seam strength and heat resistance after sewing, it is inevitable that the high strength and heat resistant fibers are woven and sewn. A sewing thread with the same high strength, heat resistance and dimensional stability as the material is required. Further, as mentioned above, in the application fields where functionality and colorfulness are required in addition to functionality as seen in sports / leisure suit applications, sewing threads that can be adapted to the color tone of the sewing material have come to be used. It was Generally, sewing threads are roughly classified into clothing sewing threads and industrial sewing threads, and the former are classified into household and industrial threads.
It is further divided into hand-sewn threads and sewing threads. Most of the industrial threads are sewing threads. In particular, industrial sewing threads were mainly cotton sewing threads and silk sewing threads, but recently, polyester fibers are being replaced. On the other hand, as a sewing thread for industrial materials, vinylon fiber, polyester fiber, nylon fiber and the like have been conventionally used depending on the application field. Recently, like the industrial sewing machine threads, polyester fibers are being replaced by polyester fibers which are more balanced in properties such as dimensional stability, heat resistance and light resistance than other fiber materials. And various improvements have been made to further improve the performance of polyester fiber, and it has excellent sewability during high-speed sewing or thick sewing,
A sewing machine thread having high seam strength has been developed (for example, Japanese Patent Laid-Open No. 59228034 and Japanese Patent Publication No. 59-10).
6535). However, compared to the seam strength and heat resistance of sewn products made of high-strength, heat-resistant fiber cloth such as the aromatic polyamide fibers, wholly aromatic polyester fibers, and polybenzazole fibers, polyester fibers Obviously, there are performance constraints. With the advent of high-strength and / or heat-resistant fibers, the development of clothing and industrial sewing machine threads using the fiber material has been studied. For example, Japanese Utility Model Laid-Open No. 52-87736 uses polymetaphenylene isophthalamide fiber. Sewing thread, and Japanese Patent Laid-Open No. 1-
Japanese Patent No. 239132 discloses a sewing thread made of polyphenylene sulfide fiber as a raw material, which has excellent heat resistance.
Japanese Patent No. 272836 discloses a composite yarn composed of meta-aramid fiber and polyphenylene sulfide fiber, which is excellent in both heat resistance and chemical resistance. JP-A-63-92745 discloses a composite yarn made of polyethylene which is lightweight, has high strength, low elongation, and light resistance. We also propose sewing threads with excellent chemical resistance.

[0003]

A conventional sewing thread made of polyester fiber, vinylon fiber or the like should sufficiently exhibit the performance of a sewn product composed of a high-strength and heat-resistant fiber material even if it satisfies the sewability. Is essentially impossible and has its own limits. Further, the sewing thread made of wholly aromatic polyester fiber is improved in seam strength as compared with the conventional polyester sewing thread and vinylon sewing thread, but has a drawback in light resistance and heat resistance. Sewing threads made of fiber are excellent in seam strength, light resistance, heat resistance, etc., but have a drawback in water resistance. On the other hand, sewing thread made of polybenzazole fiber has high strength, low elongation, and excellent heat resistance, chemical resistance, dimensional stability, etc., so it is suitable for sewing fabrics for clothing and industrial materials. Are suitable. However, the above-mentioned high-strength, high-modulus, and heat-resistant fibers are commonly dye-non-stainable, so they are difficult to use for sewing in the field of clothing apparel that requires fashionability and aesthetics. In order to eliminate this obstacle, the above-mentioned high-strength, high-modulus, heat-resistant fiber yarns may be twisted or combined with yarns dyeable with ordinary dyes or already dyed yarns. I've been told. When the twisted or twisted yarn is applied, the color of the dyed fiber yarn appears on the surface of the twisted or twisted fiber yarn at a regular pitch or has a marbling tone. It is also considered to modify the polymer into a dyeable fiber by a method such as a method of copolymerizing a monomer having a dyeing seat or a method of disturbing the regularity of the structure by introducing a third component. However, the mechanical properties and thermal properties of fibers are likely to be sacrificed.

[0004]

Means for Solving the Problems The inventors of the present invention have earnestly studied the improvement of the color tone of a sewing thread composed of a high-strength and heat-resistant organic synthetic fiber. The present invention has been made based on the finding that by covering with a short fiber, a sewing thread having a high adaptability and a wide range of adaptability can be obtained. The purpose of the present invention is mainly to eliminate the drawback of the dyeability of polybenzazole fiber sewing thread.
It is to provide a high strength and heat resistant sewing thread. That is, it is a composite yarn obtained by mixing a long fiber group and a short fiber group made of an organic synthetic polymer, and the composite yarn has a breaking strength of 3.
The object is a composite sewing thread characterized by having an initial tensile elastic modulus of 5 GPa or more and an initial tensile elastic modulus of 150 GPa or more.

The present invention will be described in more detail below. The composite sewing thread according to the present invention is composed of a high-strength and heat-resistant long fiber group made of an organic synthetic polymer and a colored short fiber group, and the short fiber is mixed with the long fiber in an entangled state. This is intended to improve the appearance, especially the color tone, of the composite sewing thread. The first requirement for the long fiber group made of the organic synthetic polymer used here is that the breaking strength after forming the composite sewing thread is 3.5 GPa or more. This depends on the type and mixing ratio of the short fiber group to be mixed, and further on the mixing form, but as the long fiber made of an organic synthetic polymer satisfying this mechanical property, a single unit represented by Chemical Formula 1 to Chemical Formula 3 is used. A polybenzazole-based fiber composed of a polymer or a copolymer to be constituted is suitable. Further, of course, a long fiber group composed of aromatic polyamide fibers, wholly aromatic polyester fibers, or the like may be mixed. When the breaking strength of the composite sewing machine thread is less than 3.5 GPa, sufficient seam strength or impact strength of the seam cannot be maintained, and a high-strength sewing product, for example, a sewing product composed of polybenzazole fiber The original performance cannot be exhibited.

[0006]

[Chemical 1]

[0007]

[Chemical 2]

[0008]

[Chemical 3]

The initial tensile elastic modulus of the composite sewing thread of the present invention needs to be 150 GPa or more from the viewpoint of sewability. If the initial tensile elastic modulus is less than 150 GPa, the loop formation of the needle thread becomes small and becomes unstable at the time of sewing, so that the lower threading error by the looper increases. For this reason, stitch skipping easily occurs and the sewability becomes inferior, which poses a problem in terms of sewing efficiency and quality. However, if the initial tensile elastic modulus becomes extremely high, the composite sewing thread becomes hard and puckering tends to occur, so that it is preferably less than 280 GPa.

In addition, when a fabric composed of heat resistant fibers in addition to high strength is to be sewn, the seams of the sewn product are naturally required to have some heat resistance, which is the second requirement. . The strength of the composite sewing thread of the present invention is basically maintained by long fibers, and the heat resistance of the long fibers is important from the viewpoint of physical properties. Considering that the ratio of the seams in the sewn product is small, it is sufficient that the sewn product has heat resistance of 400 ° C. or higher. If the heat resistant temperature is less than 400 ° C, the heat resistance of the sewn product cannot be sufficiently exhibited. As the long fibers having such a heat resistant temperature, the above-mentioned polybenzazole fibers, aromatic polyamide fibers, etc. are suitable.
Here, the polybenzazole fiber is prepared by dissolving polybenzazole in polyphosphoric acid to form a dope, and heating the dope at a temperature at which the dope flows in a spinning device and discharging the dope from a spinneret. After spraying a heated air stream on the discharged yarn to cool it, contact it with a non-solvent coagulating liquid, then wash the yarn with water to remove polyphosphoric acid, and further dry the yarn. The tensile strength is 4.0 GPa or more and the tensile elastic modulus is 140 GPa or more.

The short fiber, which is one of the constituent materials of the composite sewing thread of the present invention, is the first requirement that it can be dyed or dyed at the yarn making stage by a generally known method and conditions. Organic synthetic fibers or natural fibers which do not satisfy the above are not suitable as constituent materials for the composite sewing thread of the present invention. Next, sewability will be described. The purpose of mixing short fibers with long fibers is to give the composite sewing thread a variety of color tones, but in addition to that, it dissipates the frictional heat generated when the needle penetrates the fabric during sewing and enhances sewability. There is also a point. In other words, a significant improvement in sewability is recognized as compared with the case where dyeable long fibers are combined with high-strength, heat-resistant long fibers. However, when the short fibers to be mixed themselves lack heat resistance, there is a limit to improving the sewability by the heat radiation effect. Especially in the sewing of thick fabrics and high-speed sewing, the heat resistance of short fibers is particularly important. From this point of view, at least 200
A group of short fibers consisting of synthetic polymers or natural fibers with a melting point or decomposition temperature of ° C is required. Examples of fibers that can be colored and have heat resistance that can withstand sewing include natural fibers such as cotton and hemp, and fibers made of organic synthetic polymers such as polyester fibers and polyamide fibers.

[0012] Comparing a sewing thread composed of only long fibers with the same type of fiber material and a sewing thread composed of only short fiber groups, the former has a high strength / initial tensile elastic modulus, but has a dense structure, so that air , The heat resistance is poor because the inclusion amount is small, while the latter has a high structure because the structure is rough and the fluff has a heat dissipation effect, but the strength and the initial tensile elastic modulus are relatively low. Therefore, by mixing the long fiber group and the short fiber group, it is possible to obtain a composite sewing thread that basically has the characteristics of both the long fiber and the short fiber. Here, the term “mixing of fibers” means (1) one in which drafted short fiber groups are superposed on the outside of a long fiber group, the ends of the short fiber groups are bound by the action of an air stream, and then twisted,
(2) Those in which a drafted short fiber bundle is superposed and twisted on an opened long fiber group are included. What is important here is that it is recommended that the mixed fiber form is such that the surface of the long fiber group is substantially covered with short fibers.

Next, the mixing ratio (% by weight) of the short fiber group in the composite yarn will be described. The mixing ratio of the short fiber group in the present invention depends on the mixing or fiber mixing means and the processing conditions, but is preferably in the range of 20 to 50% by weight, more preferably in the range of 25 to 40% by weight. Mixing ratio of short fiber group is 20
If it is less than 10% by weight, the coating of the long fibers becomes insufficient and the long fibers of the core part are partially exposed to cause unevenness in the color tone of the composite yarn, which deteriorates the quality (aesthetics). In addition, the entangled state between the long fibers and the short fibers becomes poor, and the short fibers easily move due to the frictional resistance, and the sewability m decreases. On the other hand, the mixing ratio of the short fiber group is 50
When the content is more than 10% by weight, the amount of fluff increases and the uniformity of the color tone is improved, but on the other hand, the sewability deteriorates and the uniformity of the seams deteriorates. The average fineness of the short fibers is not particularly limited, but 0.5 to 10 denier is generally used, and the fineness may intentionally have an appropriate distribution. The average fiber length of the short fibers is not particularly limited, and usually 30 to 150 mm can be used.

The number of fluffs of the composite yarn is an important factor in order to improve the degree of tightness during sewing, that is, to improve the tightness of the yarn and to obtain a uniform appearance and stable sewability. In the present invention, in addition to this, the state of the fluff becomes more important in terms of color tone. That is, the composite yarn is 200 to 70 with fluff of 1 mm or more.
It is preferable to have a fluff index in the range of 0 pieces / 10 m, and when the fluff index is less than 200 pieces / 10 m, the uniformity of color tone and the degree of clogging are deteriorated, and at the same time, the effect of protecting long fibers from frictional damage is significantly reduced. To do. When the fluff index exceeds 700 pieces / 10 m, the effect of protecting the long fibers from friction damage and the effect of coating are increased, but the sewability is deteriorated, the appearance of the seam is deteriorated, and the strength as a sewing thread is insufficient. become.

The short fiber group constituting the composite sewing thread needs to be dyeable with an ordinary dye, and dyeable fibers include direct dyes, vat dyes, naphthol dyes, sulfur dyes,
It means general fibers that can be dyed with disperse dyes, reactive dyes, acid dyes, cationic dyes, etc., and natural fibers such as cotton, hemp, silk, etc., and organic synthetic fibers such as polyester, nylon, acryl, vinylon etc. are exemplified. . Of these, polyester fibers are most preferably used from the viewpoint of heat resistance and mechanical properties. The short fiber group may be dyed or colored in advance, and as the organic synthetic fiber, a fiber made of a polymer obtained by mixing a dye or a pigment may be used.

Each scale used in the evaluation of the present invention was obtained by the following procedure.

<Fineness of long fibers> Temperature 22 ° C., humidity 65 ±
A sample whose humidity was controlled for 16 hours in a constant temperature and constant temperature test room of 2 RH% was measured using a lap reel according to JIS L1013 (1981).
It measured by the method according to.

<Fineness of short fibers> Temperature 22 ° C., humidity 65 ±
A fiber sample that had been conditioned for 16 hours in a constant temperature and constant temperature test room at 2 RH% was measured using a denier computer DC-I1B manufactured by Search.

<Fracture Strength and Elongation and Initial Tensile Elastic Modulus of Long Fiber and Composite Sewing Thread> JIS L-1013 (1981)
In accordance with the Tensilon manufactured by Orientec Co., Ltd., gripping interval 20 cm, pulling speed 100% / min, n =
Ten measurements were performed and the arithmetic mean value was calculated.

<Break strength / elongation and initial tensile modulus of short fiber> In accordance with JIS L-1013 (1981), a gripping interval of 2c was obtained by a tensilon manufactured by Orientec Co., Ltd.
m, tensile rate 100% / min, and n = 10 were measured to obtain an arithmetic average value.

<Weight ratio of yarn (%)> The mixing ratio defined by the following formula was used. Mixing ratio (% by weight) = Ws × 100 / Wy Ws: Weight of short fibers constituting composite sewing thread (g) Wy: Weight of composite sewing thread (g)

<Fuzz Index> It was measured with an F-index tester manufactured by Shikishima Spinning Co., Ltd.

<Sewability> Thread breakage and skipping were evaluated by the number of defects generated when four plain knitted fabrics (using 250 denier of polybenzazole fiber) were stacked and sewn on 1,000 sheets with a flat two-needle sewing machine. The number of sewn sheets is work clothes (34 / 2S) made of polyparaphenylene benzbisoxazole fiber.
Was evaluated by the number of sheets that can be sewn for 2 m. The outer appearance of the seam is indicated by ⊚ to Δ by the visual judgment of the stitched state of the above knitted fabric. ◎ means excellent, ○ means good, and △ means normal.

<Determination of color tone> The uniformity of the color tone was visually determined. A uniform color tone without exposing the long fiber group was distinguished by ⊚, a slightly light color tone reflecting the long fiber group was distinguished by ○, and a marbling one was distinguished by ×.

[0025]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

<Examples 1 and 2, Comparative Examples 1 to 5> In the apparatus shown in FIG. 1, a swirling nozzle 2 is attached immediately after the front roller 1 of the spinning machine, and the drafting apparatus has a fineness of 1.2.
A short fiber bundle S (coarse yarn) of polyethylene terephthalate having a denier of 5 mm, a fiber length of 38 mm, a strength of 0.8 GPa, an elongation of 13.7% and an initial elastic modulus of 14 GPa is supplied to form a fleece. On the other hand, the strength is 5.8 GP with 50 denier / 24 filament from just upstream of the front roller 1 of the device.
a, elongation of 3.7%, polyparaphenylene benzbisoxazole long fiber F having an initial elastic modulus of 178 GPa is supplied and superposed on the center of the fleece, and these are introduced into the swirling nozzle 2 to obtain air pressure 4. 9 kg / cm2.
Entangling treatment was performed with G to obtain a composite yarn 3. Further, the composite yarn is twisted so as to have a twist coefficient of 3.5 (inch method) to obtain a composite yarn of English cotton count 60S, and three twisted composite yarns (Z direction) are aligned. Then, the composite yarn was twisted at 850 T / m in the direction opposite to the direction of the composite yarn (Z direction) and the composite strip was wound on cheese. This composite yarn is treated with a disperse dye (C.I. Disp.
erse Blue1, C.I. I. 64500) at 120 ° C. for 40 minutes. An oil agent mainly containing silicon was attached to the dyed composite yarn in an amount of 0.5% by weight to form a composite sewing yarn. At this time, the mixing ratio of the long fiber (F) of polyparaphenylene benzbisoxazole and the short fiber bundle (S) of polyethylene terephthalate was changed as shown in Table 1. The color tone, mechanical properties, sewability, and appearance of the seams of the composite sewing thread thus obtained were evaluated.

[0027]

[Table 1]

As is clear from Table 1, the composite sewing threads (Examples 1 and 2) belonging to the present invention did not cause thread cracking, and the color tone was good without reflecting the color of the long fiber group and uneven. It was uniform without showing a marbling tone. The strength and initial tensile modulus of this composite sewing thread are higher than those of spun thread type sewing thread, and there is little occurrence of melting or skipping of sewing thread during sewing or when sewing is stopped, and the sewability and stitch appearance are extremely high. It was good. Comparative Examples 1 to 3 exemplify the case where the mixing ratio of the short fibers is out of the preferable range of the present invention, and Comparative Example 1 in which the short fibers are not mixed naturally has a yellowish color tone of the sewing thread. Is brown and
In Example 3 in which the mixing ratio of the short fibers was small, the polyparaphenylene benzbisoxazole fiber was partially exposed on the surface of the composite sewing thread, and thus exhibited a marbling tone. In addition, the composite sewing thread with a high mixing ratio of short fibers (Comparative Example 2) and the spun thread without mixing the polyparaphenylene benzbisoxazole fiber (Comparative Example 3) had good color tone, but strength and initial elasticity. The ratio was low, and the sewability (sewing stability and stitch appearance) was poor.

<Examples 4 to 6> Polyparaphenylene benzbisoxazole filament F having 50 denier / 24 filament, strength 5.8 GPa, elongation 3.7% and initial elastic modulus 178 GPa was electro-spreaded as shown in FIG. It is supplied to the device 1 and opened, and the fineness is 1.25 denier and the fiber length is 38 m.
m, strength 0.8 GPa, elongation 13.7%, initial elastic modulus 1
A short fiber bundle S of 4 GPa of polyethylene terephthalate is superposed immediately before the front roller 2 to form a composite yarn, and the composite yarn is twisted to have a twist coefficient of 3.5 (inch system), and then English cotton. A composite yarn 3 having a count of 60S was obtained. Next, three twisted composite yarns (Z direction) were aligned and twisted at 850 T / m in the opposite direction to the composite yarn (Z direction), and the composite strip was wound on cheese. This composite yarn was mixed with disperse dyes (C.I. Disperse Blue 1, C.I. 64).
500) and stained at 120 ° C. for 40 minutes. An oil agent mainly containing silicon was attached to the dyed composite yarn in an amount of 0.5% by weight to form a composite sewing yarn. At this time, the mixing ratio of the polyparaphenylene benzbisoxazole long fiber (A) and the polyethylene terephthalate short fiber bundle (B) is shown in Table 2.
Changed as shown in. The color tone, the mechanical properties, the sewability and the appearance of the seam of the thus obtained composite sewing thread called mixed fiber type were evaluated. A composite sewing thread obtained by plying polyester spun yarn and polyparaphenylene benzbisoxazole continuous fiber under the above-mentioned twisting conditions was used in Example 6
And

[0030]

[Table 2]

As is clear from Table 2, the composite sewing threads (Examples 4 to 5) obtained by the electric opening method had a good color tone and were uniform without showing marbling. This composite sewing thread had few occurrences of fusing and skipping of the sewing thread at the time of sewing or when sewing was stopped, and the sewability and the appearance of the stitch were extremely good. The color tone of Example 6 was a marbled state, and did not fully satisfy the object of the present invention.

<Examples 7 to 8 and Comparative Example 4> Using the mixing method and mixing conditions according to Example 1, composite sewing thread was formed. At this time, types of long fibers and short fibers, short fiber strength,
The mixing ratio was changed as shown in Table 3. If the short fibers are cotton, vat dye C.I. I. Vat Blue1 C.I.
I. Using 73000 (1177), 40 g of powder dye, 40 cc of funnel oil, 3 g of caustic soda per 1000 g of cotton
5% 84cc, hydrosulfite 84g, hot water 2
An undiluted solution of 000 cc was prepared, and an appropriate amount of the undiluted solution was used as a dyeing bath to add yarns at 50 to 60 c for dyeing, and after squeezing, air-drying, washing with water and soaping were performed. Short fibers other than cotton were dyed using the disperse dye described in Example 1. The color tone, sewability and stitch appearance of the composite sewing thread thus obtained were evaluated.

[0033]

[Table 3]

As is clear from Table 3, those belonging to the present invention (Example 7) are excellent in color tone, sewability, high elongation property and heat resistance, while Comparative Example 4 which is out of the present invention is heat resistant. Due to its poor property, the short fibers were partially melted at the time of sewing, especially immediately after the sewing was stopped, and the appearance of the seam was poor. Further, since the melting point of the short fiber group is 200 ° C. or less, it is difficult to fully utilize the original heat resistance of the sewn product. Further, the color tone of the sewing machine thread containing the aramid short fibers was inferior to that of Example 7.

[0035]

According to the present invention, an arbitrary color tone can be selected, high strength and heat resistance, excellent wear resistance even at high speed sewing, stable sewability and a beautiful seam appearance, and It is possible to provide industrial sewing thread and contribute to the industrial world.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus showing an example of an air flow entanglement method used in the present invention.

FIG. 2 is a schematic view of an apparatus showing an example of an electric fiber-spreading method used in the present invention.

[Explanation of sign]

 S Short fiber bundle F Long fiber bundle 1 Front roller 2 Swirling nozzle 3 Composite yarn S Short fiber bundle F Long fiber bundle 1 Electric opening device 2 Front roller 3 Composite yarn

Claims (4)

[Claims] 1. A composite yarn of a long fiber group made of an organic synthetic polymer and a short fiber group made of an organic synthetic polymer or a natural fiber, wherein the long fiber group has a melting point or a decomposition initiation temperature of 200 ° C. or higher. A composite sewing thread in which short fibers composed of a certain fiber are mixed, breaking strength is 3.5 GPa or more, and initial tensile elastic modulus is 150 GPa or more. 2. A composite sewing thread in which the long fiber group according to claim 1 is made of a polybenzazole fiber and the short fiber group is made of a polyester fiber. 3. The composite sewing thread according to claim 1, wherein the short fiber group is contained in an amount of 20 to 50% by weight. 4. The long fiber group according to claim 1 is opened, and the short fiber group is superposed on it to obtain a breaking strength of 3.5 GPa or more,
A method for producing a composite sewing thread comprising a composite thread having an initial tensile elastic modulus of 150 GPa or more.