EP1479802B1 - Sewing thread and process of making such a sewing thread - Google Patents

Description

The present invention relates to a sewing thread having the features of the preamble of claim 1 and two methods for producing such a sewing thread.

Sewing threads are known in different constructions. For example, describes the EP 0 295 601 A a sewing yarn of multifilament synthetic fibers, wherein the known sewing yarn comprises the construction of an air-entangled sewing yarn such that a multifilament first core yarn component is entangled with the aid of air flow with a second effect yarn component. As a result of this turbulence, the individual filaments of such a sewing yarn are looped or bow-shaped, so that the thread closing of the sewing thread required for the sewing process is achieved as a result.

A second basic sewing thread construction is in the EP 0 569 891A described. In this case, a multifilament first yarn component is wound by a second yarn component, wherein then at least two, preferably three, such rovings are twisted together to produce the finished core yarn, so that by the twisting the relevant thread closure can be achieved. In order to prevent unwanted untwisting of such a twisted core yarn during its processing, prior to twisting, the rovings consisting of at least two yarn components are provided with a rotation, wherein the direction of rotation of this rotation is opposite to the direction of rotation of the twist.

From the EP 0 569 890 A Furthermore, a third, fundamental construction of a sewing thread is known. In this case, this known sewing thread construction forms the sewing thread as a thread, wherein this thread has at least two, but preferably three, multifilament yarn components. Each yarn component forming the yarn is also pre-twisted prior to twisting, with the pre-twist of each multifilament yarn component also being opposite in direction to the direction of twisting.

From the EP 0 919 649 A For example, a sewing thread made of synthetic multifilaments is known, wherein the known sewing thread has at least two yarn components whose individual filaments are aligned parallel to each other. These two yarn components are wound together, wherein to achieve the required thread closure then the twisted two yarn components are provided over their entire surface on their surface with a polymeric coating. In other words, this known sewing thread thus has two mutually twisted multifilament yarn components, but in each yarn component all the filaments are aligned parallel to one another. In order to prevent in this Nähgarnkonstruktion then shifting the two yarn components relative to each other during the sewing process, the known sewing yarn is covered over the entire surface of the polymeric coating, so that accordingly, for example, at the yarn brake of the sewing machine or a deflection of the sewing yarn no filaments with the yarn brake or . Contact the deflecting members, since the polymeric sheath prevents this contact. Therefore, in this embodiment, the sewing thread required for the sewing thread take-up is provided primarily by the full-surface wrapping available.

The known sewing yarns described above, which have the construction of a core yarn, a swirled sewing yarn, a sewing thread or a full-surface coated sewing yarn, can be used only to a limited extent for the sewing of elastic articles. For this purpose, it is usually necessary to create the seam using the known sewing threads such that the known sewing threads are present with a Garnüberlänge in the seam, so that in this way, the otherwise inflexible seam has a certain elasticity, but this includes the disadvantage that thereby a considerably larger amount of sewing thread is required.

The present invention has for its object to provide a sewing yarn, in particular for use in elastic articles available, which is particularly economical to use.

This object is achieved by a sewing yarn with the characterizing features of claim 1.

The sewing thread according to the invention, like the known sewing threads described above, consists of multifilament synthetic fibers and / or fiber yarns, wherein the sewing thread has at least one yarn component of poly-trimethylene terephthalate fibers. In contrast to this, however, the ready-to-use sewing thread according to the invention has a maximum tensile force elongation of between 25% and 85%, this maximum tensile elongation at break and the absolute strength being determined in a conventional manner by a conventional force-strain measuring method based on DIN EN ISO 2062. Furthermore, the sewing thread according to the invention has an elastic elongation, which is between 30% and 95% of the elongation, which is determined at a measuring force which corresponds to 70% of the absolute strength of the respective sewing thread. This is expressed by the term gel-elastic elongation brought that after a corresponding, repeated repeated loading and subsequent discharge the sewing thread according to the invention still has an elasticity in the aforementioned size. The repeated in the present invention for the characterization of the invention. Sewing yarn as well as the method used feature of the elastic elongation is determined as described specifically concretely in the embodiment below.

Surprisingly, it was found that such a sewing thread stitched properly and can be used in particular for sewing elastic items, although the experts had previously believed that such a highly elastic sewing thread can not trouble-free and especially not machine sew

Elastic articles in the sense of the present application are all articles that are subjected to a load, i. experienced in a force application, a reversible increase in length, the term elastic articles in particular knitted and knitted garments from the field of underwear, swimwear, sportswear, blouses, T-shirts, sweatshirts, sweaters and corsetry but also elastic and in particular woven outerwear articles, such as elastic pants and preferably elastic jeans, as well as elastic technical articles, such as seat covers for vehicle seats covers.

The term fiber yarn, as used herein, which corresponds to the terms staple fiber yarn, refers to such yarns made from a plurality of individual fibers (staple fibers) with a limited length, for example a staple length between 12 mm and 160 mm, preferably spun , are. In particular, it should be noted as the first significant advantage of the sewing yarn according to the invention that can be produced by using the sewing thread according to the invention in elastic articles such seams, even without the provision of Garnbeflängen previously described in the seam, as always required in the known sewing threads, perfectly create elastic seams. This advantage is particularly evident when using the sewing thread according to the invention lockstitch seams of the stitch type 301 to DIN 61400 are created, in which case the sewing thread according to the invention on lockstitch machines at speeds between 2,500 revolutions / min to 5,000 revolutions / min and a stitch density of has up to 5 stitches / cm only one thread breakage frequency of less than two yarn breaks / hour in continuous use.

In addition, the seams created with the sewing thread according to the invention, in particular lockstitch seams, have an excellent seam elasticity, which is also present if there is no or only a very small yarn excess length of the sewing yarn in such a seam, wherein due to the high elasticity of the invention Sewing yarn and in particular the high elastic elongation of the same ensured that even after repeated loading and after repeated overloading of the seam no undesirable opening of the seam occurs, as the sewing yarn conforms to the elasticity of the elastic article. In addition to the above-described excellent sewability, even with the use of fine needles, and its elastic behavior occurs in the sewing thread according to the invention also no undesirable warping or displacement of the sewing yarn according to the invention in the seam, so that the seams created with the sewing thread according to the invention always a flawless and imparted optimized optics and also characterized by a high fluffiness, softness and suppleness, so that the sewing thread according to the invention especially for worn on the skin garments as is considered particularly pleasant and thus conveys a high wearing comfort. Due to the aforementioned high fluffiness, softness and suppleness of the sewing yarn according to the invention, this also allows sewing of a plurality of fabric layers arranged one above the other, without a seam thus created being perceived as being troublesome when the prefabricated part is worn.

Due to the fact that in the seams created using the sewing yarn according to the invention no or only a significantly reduced Garnüberlänge is provided in this seam, the sewing yarn according to the invention, which, as already stated above, has excellent machine sewability, particularly economical process, where This sewing thread saving compared to conventional sewing threads, which require a correspondingly large Garnüberlänge in the seam, between 20% and 40%, based on the respective seam to be created and in particular in a lockstitch seam, required Nähgarnlänge.

The advantages described above occur increasingly when the sewing thread according to the invention has a maximum tensile strength between 35% and 70% and when in this embodiment of the sewing yarn according to the invention has a tensile elastic strain, which is between 50% and 80% of the elongation at a measuring force is determined, which corresponds to 70% of the absolute strength of the respective sewing thread. Here it has been found that this preferred embodiment of the sewing yarn according to the invention in a variety of elastic articles that differ by the degree of their elasticity can be universally applied, in particular with the sewing thread according to the invention then lockstitch seams are machined under the conditions specified above ,

In principle, the multifilament synthetic yarn of the invention can contain any synthetic fibers which give the ready-to-use sewing thread the aforementioned maximum tensile elongation at break and the aforementioned elastic elongation. Thus, the sewing thread according to the invention may comprise or consist of corresponding polyethylene terephthalate fibers or polyamide 6 or polyamide 6.6 fibers.

The sewing thread of the invention has at least one yarn component consisting of a multifilamentary poly-trimethylene terephthalate fiber or a fiber yarn. In other words, the sewing yarn of the present invention contains either the aforementioned multifilamentary poly-trimethylene terephthalate fiber or the above-mentioned fiber yarn of poly-trimethylene terephthalate fibers, or else the sewing yarn of the present invention consists in particular of at least one multifilamentary poly-trimethylene terephthalate fiber and / or at least one fiber yarn of poly-trimethylene terephthalate fibers.

With regard to the construction of the sewing thread according to the invention, it should be noted that the sewing thread according to the invention may have the constructions as described in the background in the prior art, as long as it is ensured that such a construction the sewing thread according to the invention a maximum tensile force between 25% and 85%, preferably between 35% and 70%, and provides a ductile elongation which is between 30% to 95% and in particular between 50% and 80% of the elongation determined at a measuring force corresponding to 70% of the absolute strength of the respective sewing yarn ,

However, it is particularly suitable if the sewing thread according to the invention has the construction of a sewing thread, wherein this, characterized by an excellent processing behavior further distinguished sewing thread then at least two twist components and preferably three twist components. Surprisingly, it could be found that such a twisted construction gives the seam produced herewith excellent elasticity, although conventional sewing thread yarns are characterized by a relatively inelastic behavior due to the design.

In particular, when the Nähzwirn forming, twisting components are provided with a pre-rotation, preferably this pre-rotation in S-direction, and the pre-twisted twist components are then twisted together to form the Nähzwirnes, said twisting is preferably carried out in the Z direction draws such a development; of the sewing thread according to the invention by a high processing security during sewing, i. thus by an even lower thread breakage frequency, in combination with a high Nahtelastizität, so that the seams created herewith do not lose their elasticity even after multiple load and discharge.

A particularly suitable development of the sewing yarn according to the invention provides that in this case the thread components forming the sewing thread have a pre-rotation with a rotation coefficient α between 50 and 130 and in particular between 70 and 100, whereas the sewing thread created therefrom then has in particular a rotation coefficient α ', which varies between 80 and 160, and preferably between 95 and 125.

Here, the rotation coefficient α or α 'is defined as follows: $$\mathrm{Rotation\; coefficient\; \alpha }=\frac{\mathrm{Turns\; per\; meter}}{\sqrt{\mathit{nm}}}$$

In this formula, Nm means the yarn count (total titer) of each pre-twisted twist component indicated in number metric: $$\mathrm{Rotation\; coefficient\; \alpha \text{'}}=\frac{\mathrm{Turns\; per\; meter}}{\sqrt{\mathit{nm}}}$$

In this formula, Nm means the yarn count (total titer) of the total twist, given in number metric.

In the foregoing, for the sewing thread of the present invention which has the construction of a twist in the embodiment described therein, there are given ranges for rotation coefficients α (pre-twist) and α '(twist twist), respectively. If the sewing thread according to the invention is formed from multifilament yarn components, the twist coefficient α varies in particular between 50 and 100 and the twist coefficient α 'varies between 80 and 125, while when using fiber yarns for producing the twisted sewing thread according to the invention, in particular the twist coefficient α between 90 and 130 and the Rotation coefficient α 'is between 115 and 160.

In a fundamentally different, but also preferred and particularly suitable embodiment of the sewing thread according to the invention, the sewing thread according to the invention has the construction of a swirled yarn, the swirled yarn comprising at least a first yarn component forming the core of the yarn and at least one second yarn component interlaced therewith, such that the second yarn component forms the fancy yarn component. In comparison with the previously described twisted construction of the sewing thread according to the invention, this swirled sewing thread structure gives the sewing thread according to the invention a particularly high softness and particularly skin-friendly suppleness, so that this construction is always preferably selected when the sewing thread according to the invention is for sewing used by such elastic articles which are worn directly on the skin or which are particularly tight against the skin.

Particularly, in the above-described specific construction of the sewing yarn of the present invention, which is a swirling sewing yarn, both the first yarn component and the second yarn component are composed exclusively of multifilamentary poly-trimethylene terephthalate fibers, such a specific embodiment of the sewing yarn of the present invention has one high elasticity in conjunction with an optimal zugelastic Dehnungsanteil so that seams made therefrom, no Nähgarnüherlängen in the. Seam must have more. Therefore, such a sewing yarn can be processed with high economy due to the above-described sewing thread saving.

In a further development of the sewing thread according to the invention described above, this development also has the construction of a swirled sewing yarn, but the first yarn component, i. the core yarn component constituting the multifilamentary poly-trimethylene terephthalate fiber, while the second yarn component constituting the effect yarn component is a polyethylene terephthalate fiber and hence, in chemical structure, a conventional multifilament polyester fiber.

In particular, when the mass ratio of the first yarn component to the second yarn component varies between 60:40 to 80:20 in the development described above, the effect yarn component, in particular if it has a higher single filament count and a smaller Einzelfilamenttiter compared to the core yarn component, fully or almost Completely the core yarn component, so that this embodiment of the sewing yarn according to the invention is then preferably selected for such sewing threads, which are offered in medium to dark shades. Here it has been found that this development of the sewing yarn according to the invention in medium to dark shades can be particularly true color, so that accordingly, such a dyed sewing thread according to the invention has high fastness properties and preferably high wet fastness properties.

In order to further improve the processing properties of the sewing yarn of the invention having the construction of a entangled sewing yarn, without thereby reducing the required elasticity, i. the elastic elongation is lost or appreciably impaired, another development of the sewing thread according to the invention provides that in this case the sewing thread with a rotation .between 0 turns / m and 500 turns / m, in particular between 80 turns / m and 250 turns / m, is provided. Such an embodiment of the sewing yarn of the present invention combines optimum machine bonding properties, i. a further reduced thread breakage frequency, with a high elasticity, so that in particular particularly zuzupspliche elastic articles and preferably using a lockstitch seam of the stitch type 301 (DIN 61400) can be sewn.

In order to prevent unwanted beading of the seams in later use, and in particular in the care of the sewn with the sewing thread according to the invention, the sewing thread according to the invention, preferably the dyed sewing thread, in particular a hot air shrinkage at 180 ° C between 0.5% and 3 % and preferably between 0.6% and 1.5%, and a boiling shrinkage at 98 ° C in water between 0.1% and 1.5%, and preferably between 0.15% and 0.8%. Here, the hot air shrinkage at 180 ° C for 15 minutes and the boiling shrinkage in water at 98 ° C is determined during 15 minutes. In principle, the strength to be provided in the sewing thread according to the invention depends on which yarn components are used for producing the sewing thread, which sewing thread construction is selected, for what purpose and in which. Seam construction, the sewing thread according to the invention is used. For particularly fine, elastic articles in which the seam is not exposed to extreme loads, a preferred embodiment of the sewing yarn according to the invention has an absolute strength between 400 cN and 900 cN and specific strength between 10 cN / tex and 25 cN / tex, with a such embodiment of the sewing thread according to the invention then either the construction of a double-twisted yarn, which is preferably created using fiber yarns, or has the construction of a lüftverwirbelten multifilament sewing yarn. If, on the other hand, elastic articles which are more heavily loaded are sewn with the sewing thread according to the invention, then those embodiments of the sewing thread are used whose absolute strength is in particular between 900 cN and 1300 cN and whose specific strength is between 30 cN / tex and 45 cN / sec. vary. In particular, multifilament triple-twisted or air-twisted multifilament constructions are used for this purpose. For extremely stressed seams, for example seams on elastic sports articles, such embodiments of the sewing thread according to the invention are used, which preferably have the construction of a multifilament triple thread or an air-twisted sewing thread, wherein the absolute strength in particular between 1300 cN and 1800 cN and the specific strength preferably between 45 cN / tex and 60 cN / tex, so that in summary it should be noted that the absolute strength of the sewing yarn according to the invention in particular between 400 cN and 1800 cN and the specific strength of the sewing yarn according to the invention preferably between 10 cN / tex and 60 cN / tex and preferably between 14 cN / tex and 34 cN / tex.

Likewise, the total titre of the sewing thread according to the invention is determined by what the sewing thread according to the invention is used for and with which stitch type this sewing thread according to the invention is then sewn. Thus, it has been found that a total denier of the invention sewing yarn varying between 100 dtex and 1800 dtex and preferably between 200 dtex and 1200 dtex covers a variety of applications of the sewing yarn of the present invention in sewing a wide range of different elastic articles, so that the sewing thread according to the invention preferably has the aforementioned total titre.

Embodiments of the sewing yarn of the invention containing or consisting of a multifilament poly-trimethylene terephthalate fiber are described above. In this case, these embodiments have such a poly-trimethylene terephthalate fiber whose individual filament number varies between 18 filaments and 90 filaments and in particular between 30 filaments and 60 filaments. This means that the corresponding sewing thread of the present invention made therefrom, when constructed as a double-twisted yarn, in particular between 36 filaments and 180 filaments, and when constructed as a triple-twisted yarn, preferably has between 54 filaments and 270 filaments. the number of filaments in a swirled sewing thread according to the invention then varying in particular between 36 and 180 filaments, if this swirled sewing thread is constructed only from a single core yarn component (first yarn component) and a single effect yarn component (second yarn component).

On the other hand, if the sewing thread according to the invention is produced from a fiber yarn of poly-trimethylene terephthalate fibers, then such fibers are used for this purpose selected, the staple length preferably varies between 25 mm and 110 mm and in particular between 35 mm and 90 mm.

Particularly suitable embodiments of the sewing yarn according to the invention are those in which the sewing thread according to the invention has a sliding value between 130 cN and 200 cN and in particular a sliding value between 140 cN and 160 cN. Here it has been found that adhering to these gliding the sewing thread according to the invention for sewing a variety of different elastic articles can be used particularly easily, and in particular the aforementioned Gleitwertbereich ensures that perfectly and permanently elastic lockstitch seams are created with the sewing thread of the invention can be perceived as particularly skin-friendly especially in the laundry area.

It may be emphasized once again that all the above-described embodiments of the sewing yarn according to the invention in comparison with conventional sewing threads in the creation of elastic seams and in particular in the preparation of elastic lockstitch seams have the essential advantages in terms of cost that the using the invention Sewing threads created seams require a significantly lower Nähgarnlänge to provide a comparable with conventional sewing threads Nahtelastizität. Furthermore, for the first time the sewing thread according to the invention makes it possible for trouble-free machine production of a lockstitch seam in the case of elastic articles, so that the lockstitch seam produced in this way advantageously replaces the chainstitch seam produced today with conventional sewing yarns, such a lockstitch seam offering further aesthetic design possibilities compared to the chainstitch seam and being substantially skin-symmetrical, since it applies substantially less in comparison with the chainstitch seam. Therefore, the sewing thread according to the invention can be used particularly advantageously in particular for sewing a plurality of fabric layers arranged one above the other.

A further object of the present invention is to provide two processes for the production of the above-described sewing thread according to the invention, which enable a reproducible production of this sewing thread.

This object is achieved by a method with the characterizing features of claim 19 and by a method with the characterizing features of claim 21.

A first, fundamental possibility for producing the sewing thread according to the invention provides that two or three yarn components, which are preferably either multifilament yarn components or fiber yarn components, are pre-turned independently of one another. For each yarn component, a poly-trimethylene terephthalate fiber is selected. Each pre-twisted yarn component has a maximum tensile strength of between 25% and 85%, preferably between 35% and 70%, and such elastic elongation is between 30% and 95%, preferably between 50% and 80%, of the elongation at a measuring force which corresponds to 70% of the absolute strength of the respective sewing thread. The pre-twisted yarn components are twisted together to form a twist, and the yarn thus prepared is thereafter subjected to a hydrothermal treatment. It should first be noted that the term hydrothermal treatment covers any thermal treatment which is carried out with the addition of water or in an aqueous liquor itself, so that in particular as a hydrothermal treatment, a treatment in a steam atmosphere, preferably in a saturated steam atmosphere or in a superheated steam atmosphere , or a treatment in an aqueous liquor, in particular in a dyeing liquor and / or in a finishing liquor, is to be understood.

The above-described first possibility of the method according to the invention has the advantage that a high-performance sewing thread can be produced with relatively few production steps. Due to the small number of process steps required in the process according to the invention, the error probability is reduced, so that particularly reproducible and inexpensive sewing thread can be produced according to the invention having the advantages repeatedly mentioned above, so that to avoid repetition of the above statements on the invention Sewing yarn is referred to, which are analogous or identical to apply to the inventive method.

A particularly advantageous development of the above-described first possibility of the method according to the invention provides that in this case the two or three yarn components, which are preferably, as already mentioned above, either multifilament yarn components or fiber yarn components and which form the sewing thread, with a Rotation coefficient α between 50 and 130 and in particular between 70 and 100 are pre-rotated, this rotation is carried out in particular in the S direction. Subsequently, the pre-twisted yarn components are twisted together with a rotation coefficient α 'between 80 and 160 and in particular between 95 and 125. For the aforementioned narrower ranges of the rotation coefficients α and α 'apply Depending on the respective yarn component, ie whether a multifilament yarn component or a fiber yarn component is used here, the embodiments as disclosed above for preferred developments of the sewing thread according to the invention. Here it could be found that such a constructed sewing thread shows a perfect machine sewing behavior, so that the thread breakage frequency during sewing, especially in a lasting sewing of several hours, is reduced to a minimum, so that in such a sewing thread produced no yarn breaks or maximum On average, up to 1.8 thread breakages per hour occur, as already explained in detail in the sewing yarn according to the invention.

The basically second possibility for producing the sewing thread according to the invention provides that at least two multifilament yarn components are intermingled with each other, wherein at least the core yarn component, but preferably each yarn component a maximum tensile force between 25% and 85%, preferably between 35% and 70%, and a has such elastic elongation, which is between 30% and 95%, preferably between 50% and 80%, of the elongation determined at a measuring force corresponding to 70% of the absolute strength of the respective sewing yarn, and wherein the fluidized yarn a hydrothermal treatment is subjected. For each yarn component, a poly-trimethylene terephthalate fiber is selected.

In contrast to the above-mentioned prior art according to the EP 0 295 601 A differs this fundamental second possibility of the method according to the invention for producing the sewing yarn according to the invention in that in this case for the known turbulence at least one such multifilament core yarn component and preferably such multifilament yarn components (core and effect yarn components) are used, the aforementioned maximum tensile elongations and the have the aforementioned elastic strains.

By further provided in both ways of the method according to the invention thermal treatment is achieved that the sewing yarns thus prepared are stabilized in particular for the actual sewing process, so that they then in the sewn state, a zugelastische elongation, i. Thus, a reversible elongation possess, which allows the sewing thread according to the invention even without the provision of a Garnüberlänge in the seam previously described in the invention sewing thread high elasticity, which is particularly useful when sewing elastic articles and preferably when using lockstitch Sewing has proven to be a special advantage.

In order to further increase the softness of the sewing thread according to the invention, a further development of the method according to the invention provides that two multifilament yarn components are intermingled with each other, the first yarn component forming the core of the yarn having a lead between 2% and 15%, in particular between 3%. and 6%, and the second fancy yarn component having a lead between 5% and 40%, preferably between 17% and 30%, are fed to the fluidizing step. In this variant of the method according to the invention thus the lead of the second yarn component (fancy yarn) is substantially higher than the lead of the first yarn component (core component), so that due to these Voreilungsunterschiede the sewing yarn thus produced an increased volume and improved softness and suppleness and increased Wearing comfort is awarded.

In principle, in the case of the two above-described possibilities of the method according to the invention for all yarn components which form the sewing thread or the entangled sewing thread, such synthetic fibers, for example polyester fibers, polyamide 6 or polyamide 6.6 fibers can be selected which have the abovementioned Have maximum tensile strains and the previously specified elastic strains. However, in a particularly suitable development of the process according to the invention, these yarn components, poly-trimethylene terephthalate fibers, which are a fiber yarn or a multifilament, are selected so that the sewing thread or the sewing yarn thus produced preferably consists exclusively of these multifilament poly-trimethylene terephthalate fibers and / or of fiber yarns of poly-trimethylene terephthalate fibers.

A particularly suitable variant of the process according to the invention provides that a multifilament poly-trimethylene terephthalate fiber is selected here as the first yarn component (core yarn component) and a multifilament polyethylene terephthalate fiber as the second yarn component to produce the entangled sewing yarn, so that over the Cross-section of the swirled sewing yarn thus produced seen the first yarn component, ie the multifilament poly-trimethylene terephthalate fiber, from the second yarn component, i. the multifilament poly-ethylene terephthalate fiber, is largely covered. This variant of the method according to the invention is used in particular for producing such entangled sewing yarns intended for dyeing in medium and deep shades, since the dyed sewing yarns thereby have a high level of fastness, as already described above in the related embodiment of the sewing yarn according to the invention.

In principle, with respect to the temperature at which the hydrothermal treatment is carried out, it should be noted that this temperature for the respective material must be above its glass transition temperature and below its melting point. Preferably, however, hydrothermal Treatment, which is to be regarded as a particularly suitable embodiment of the method according to the invention, carried out at an effective temperature between 120 ° C and 200 ° C, with a relevant treatment in an aqueous liquor is particularly preferred. Here, the effective temperature is determined by means of differential thermal analysis. This differential thermal analysis records the partial melting of the crystallites formed by the thermal treatment and in particular by the hydrothermal treatment in the fiber substrate in the non-crystalline regions in the form of an endothermic peak, this endothermic peak then being defined as the effective temperature of the respective thermal treatment like this in " HK Rouette, Lexicon for Textile Finishing, Laumann-Verlag, Dülmen, 1995, Volume 1, pp. 390-392 "briefly described and detailed in the Publication HJ Berndt, Dissertation TH Aachen (1971 ) "Investigation of thermo-mechanically pretreated polyethylene glycol terephthalate - a contribution to the optimization of the fixing effect and its determination" is set out in full.

As has already been pointed out above in the process according to the invention, a hydrothermal treatment is carried out, it being particularly advantageous here for the yarn to be wound onto a bobbin for the hydrothermal treatment and then the bobbin wound with the yarn for hydrothermal treatment is subjected. With regard to the residence time in such a thermal treatment is to be noted that in this case the residence time in the treatment medium and in particular in the aqueous liquor generally depends on the selected temperature. At relatively low temperatures of the treatment medium or the aqueous liquor, such as temperatures between 80 ° C and 100 ° C, usually the residence time varies between 30 minutes and 2 hours, while at temperatures between 100 ° C and 130 ° C, the residence time between 45 minutes and 1.5 hours, preferably between 50 minutes and 70 minutes. Clarifyingly, it should be noted the temperatures specified above indicate the temperatures of the treatment medium and in particular the bath temperatures of the aqueous liquor.

A further development of the method according to the invention provides that in this case the yarn, be it the twisted sewing thread or the entangled sewing thread, is dyed and / or finished after the hydrothermal treatment. This is then followed in this development of the method according to the invention stretching of the dyed and / or finished yarn, which is increased by this stretching in particular the proportion of zugelastischen stretching and / or the elastic elongation is further stabilized, so that even with repeated loads and subsequent Reliefs the yarn maintains its original elastic behavior. In other words, this stretching of the dyed and / or finished yarn also serves in particular to further stabilize the elasticity of the sewing yarn according to the invention.

With respect to the temperature at which the dyed and / or finished yarn is drawn in the previously described embodiment of the method according to the invention, it should be noted that this temperature depends on the degree of desired stabilization of the ductile elongation, i. thus the elasticity behavior of the sewing yarn according to the invention, directed. In particular, this stretching is carried out in a temperature range between room temperature and 180 ° C, wherein particularly preferably a cold drawing, i. thus a stretching between 15 ° C and 40 ° C, is performed.

As regards the force to be used in the above-described drawing, it should be noted that this force preferably varies between 0.2 cN / dtex to 1.5 cN / dtex, in particular between 0.3 cN / dtex and 1 cN / dtex, the above specified values the Defining forces that act on the yarn according to the invention during the actual drawing process.

As already stated above, in the method according to the invention, in addition to the hydrothermal treatment, this stretching step can be carried out under the above-mentioned stresses.

From the point of view of a particularly rational process sequence, a further embodiment of the method according to the invention provides that in this case also the hydrothermal treatment described above is carried out under tension. In order to effect this treatment of stress in the hydrothermal treatment, a development of the method according to the invention proposes that the twisted or swirled sewing yarn is wound with tension on a spool directly after its production, in which case the stresses are preferably used, as described above for the additional stretching step has been quantified. However, it is particularly suitable if, in this variant of the method according to the invention, the twisted or entangled sewing yarn is wound onto the spool with such a tension that the spool has a winding density between 350 g / l and 550 g / l, in particular between 400 g / l and 550 g / L.

It has repeatedly been stated above that the sewing thread according to the invention or the sewing thread produced by the method according to the invention is preferably used for the manufacture of elastic articles. In particular, however, the sewing thread according to the invention or the sewing thread produced by the method according to the invention is used for creating lockstitch seams in elastic garment parts, preferred examples of such elastic garment parts are also referred to above as elastic articles. In particular, the sewing thread according to the invention is also used as an embroidery thread in a machine creation of embroidery pattern, preferably plastic embroidery patterns in elastic articles, since it also has excellent running properties with a minimized susceptibility to mechanical Versticken for this application.

Advantageous developments of the sewing yarn according to the invention and the method according to the invention are specified in the subclaims.

The method according to the invention will be explained in more detail below with reference to an exemplary embodiment, wherein the exemplary embodiment describes a 3-fold sewing thread produced by the method according to the invention.

embodiment

On a conventional twisting machine, three multifilament poly-trimethylene terephthalate fibers (chemically modified polyester fibers) with a single denier of 84 dtex and a filament number of 36 were pre-twisted at 820 turns / min in the S direction.

Subsequently, the thus pre-twisted rovings were twisted to form a triple twine with a twist of 615 turns / m in the Z direction. The yarn thus obtained was wound up on a bobbin directly on the twisting machine, the winding density being 450 g / l.

The cheese thus prepared was then subjected to a hydrothermal treatment in an aqueous liquor, the aqueous liquor consisting exclusively of water. The residence time for this hydrothermal treatment was 60 minutes at a final temperature of 120 ° C. This was the aqueous liquor, starting with a starting temperature of 70 ° C, heated at a heating rate of 1 ° C / min to 120 ° C, thereafter allowed to dwell for 60 minutes at 120 ° C and then cooled to 70 ° C at a cooling rate of 3 ° C / min.

Following this hydrothermal treatment, the bobbin was then dyed in a conventional dyeing autoclave at 120 ° C for 60 minutes, as is common for a polyester fiber. The heating characteristic of this dyeing corresponded to the heating characteristics described above in the hydrothermal treatment.

From the sewing thread thus prepared, the following technological data were obtained, which are shown in Table 1 below. <b> Table 1 </ b> technological data of the ready-to-use sewing thread fineness 102 dtex x 3 Maximum tensile ** 752 cN Breaking extension ** 68% Toe elastic elongation * 70% twist 930 tours / m S-direction ply twist 720 tours / m Z direction sliding value 143 cN denomination-related maximum tensile strength 24 cN / tex ** measured according to DIN EN ISO 2062
* calculated as below:

The determination of the elastic elongation, which is also referred to below as "ZD", of the ready-to-use sewing thread takes place in accordance with DIN 53835.

This maximum tensile force in the example chosen was 752 cN, as summarized in Table 1.

Subsequently, the ready-to-use sewing thread 50 is subjected to load cycles, wherein each load cycle comprises stretching the sewing thread with a force corresponding to 70% of the maximum tensile force and then relaxing it to a tensile force of 20 cN (corresponding to the measured base load). This measurement was carried out on the basis of DIN 53835.

In this specific case, a force of 526.4 cN (plus a basic load of 20 cN) was used for each load cycle.

At the end of the 50 load cycles, on the one hand, the total elongation, hereinafter referred to as "GD", of the sewing yarn and the mean value of the elongations to which the sewing yarn originates in each discharge are determined. This mean will be referred to as "MD" below.

In this particular case, a total elongation at a measurement force of 526.4 cN of 47.6% (GD) and a mean value of elongation after unloading (MD) of 14.28% was determined.

The elastic elongation (ZD) in% is calculated according to the following formula: $$\mathrm{elastic\; elongation}\left(\mathrm{ZD}\right)\mathrm{in}\%=\frac{\left(\mathrm{DG}\left[\%\right]-\mathrm{MD}\left[\%\right]\right)\times 100\left[\%\right]}{\mathrm{DG}\left[\%\right]}$$

$$\mathrm{ZD}=70\%$$

Based on the specific case, the elastic elongation is calculated as follows: $$\mathrm{ZD}=\frac{\left(47.6\%-14.28\%\right)\times 100\%}{47.6\%}$$

$$\mathrm{ZD}=70\%$$

Furthermore, on a industrial sewing machine at a speed of 2,500 rpm with the sewing thread using a lockstitch, stitch type 301, DIN 61400 at a stitch density of 5 stitches / cm, a continuous load of the sewing thread was made to hold the sewing thread breaks / hour. As an average of a total sewing time of 5 hours, the sewing twist breakage frequency was found to be 1.8 breaks / hour.

The determination of the floating value shown in Table 1 was carried out as follows:

For the measurement of the floating value a measuring device of the company Honigmann (Wuppertal) with the designation "HCC- μ- meter, precision friction coefficient measuring device" is used.

The measuring principle is based on that the sewing thread to be tested is withdrawn at a constant speed of 2 m / min, after previously the sewing yarn has been guided by a loaded tension disk arrangement, as it corresponds to the tension disk arrangements usual on sewing machines. In this case, the force required for the removal of the sewing yarn, which is indicated in Table 1 as a floating value, measured.

The tension disc assembly used consists of two, pressed against each other tension discs made of polished stainless steel.

For calibrating the measuring arrangement, a commercially available standard sewing thread, type Serafil 80 (3-fold twist, polyethylene terephthalate, endless, manufacturer: Amann) is used. In this case, the load on the tension discs is changed during the withdrawal of the standard sewing thread at the aforementioned speed until a running value of 110 cN for this standard sewing thread is determined.

With the load of the tension discs thus set, the above-described measurement of the sewing yarn to be tested is then carried out.

Claims (30)

1. A sewing thread consisting of synthetic fibers, whereby the sewing thread has at least one yarn component, made of poly-trimethylene-terephthalate-fibers, characterized in that

   a) the ready-to-use sewing thread has an elongation at break between 25 % and 85 %, and

   b) the sewing thread has an elastic tensile elongation of between 30 % and 95 % of the elongation, which is determined at a measuring strength corresponding to 70 % of the absolute strength of the respective sewing thread.
2. The sewing thread according to claim 1, characterized in that the ready-to-use sewing thread has an elongation at break between 35 % and 70 %, and that the elastic tensile elongation of the sewing thread is between 50 % to 80 % of the elongation.
3. The sewing thread according to claim 1 or 2, characterized in that the sewing thread contains multifile poly-trimethylene-terephthalate fibers as poly-trimethylene-terephthalate-fibers.
4. The sewing thread according to claim 1 or 2, characterized in that the sewing thread contains fiber yarns of poly-trimethylene-terephthalate fibers.
5. The sewing thread according to claim 3 or 4, characterized in that the sewing thread consists of the multifile poly-trimethylene-terephthalate fibers and/or the spun yarn of poly-trimethylene-terephthalate fibers.
6. The sewing thread according to claim 5, characterized in that the sewing thread has the structure of a plied sewing thread, and that the plied sewing thread has at least two twisted yarn components.
7. The sewing thread according to claim 5, characterized in that the twisted yarn components are provided with a pretwisting, and that the pretwisted twisted yarn components are twisted with one another to form the plied sewing thread.
8. The sewing thread according to claim 7, characterized in that the pretwisting has a twist value a between 50 and 130.
9. The sewing thread according to claim 7, characterized in that the plied sewing thread has a twist value α' between 80 and 160.
10. The sewing thread according to one of the preceding claims 1 to 5, characterized in that the sewing thread has the structure of a intermingled yarn, that the intermingled yarn comprises at least a first yarn component forming the core of the yarn and at least a second yarn component intermingled with the latter, whereby the second yarn component forms the effect yarn component, and that the first yarn component and the second yarn component exclusively consist of the multifile poly-trimethylene-terephthalate-fibers.
11. The sewing thread according to claim 10, characterized in that the mass ratio of the first yarn component to the second yarn component varies between 60:40 to 80:20.
12. The sewing thread according to claim 10 or 11, characterized in that the sewing thread is provided with a twist between 0 rpm and 500 rpm.
13. The sewing thread according to one of the preceding claims, characterized in that the sewing thread has a hot-air shrinkage at 180 °C between 0,5 % and 3 % and a boiling shrinkage at 98 °C in water between 0,1 % and 1,5 %.
14. The sewing thread according to one of the preceding claims, characterized in that the sewing thread has an absolute strength between 400 cN and 1800 cN.
15. The sewing thread according to one of the preceding claims, characterized in that the sewing thread has a specific strength between 10 cN/tex and 60 cN/tex, preferably between 14 cN/tex and 34 cN/tex.
16. The sewing thread according to one of the preceding claims, characterized in that the sewing thread has an overall fineness between 100 dtex and 1800 dtex, preferably between 200 dtex and 1200 dtex.
17. The sewing thread according to one of the preceding claims, characterized in that the multifile poly-trimethylene-terephthalate-fibers has a single filament count between 18 filaments and 90 filaments.
18. The sewing thread according to one of the preceding claims, characterized in that the sliding value of the sewing thread varies between 130 cN and 200 cN.
19. A method for producing a sewing thread according to one of claims 1 to 9 and 13 to 18, whereby two or three yarn components are pretwisted independently of one another and the pretwisted yarn components by forming the plied yarn are twisted with one another, characterized in that for each yarn component a poly-trimethylene-terephthalate-fiber is choosen having

    a) an elongation at break between 25 % and 85 % and

    b) an elastic tensile elongation of between 30 % and 95 % of the elongation, determined by a measuring strength, corresponding to 70 % of the absolute strength of the respective sewing thread, and that

    c) the so produced plied yarn is subjected to a hydrothermal treatment.
20. The method according to claim 19, characterized in that the two or three yarn components are pretwisted with a twist value a between 50 and 130 and in that the pretwisted yarn components are twisted with one another with a twist value α' between 80 and 160.
21. A method for producing a sewing thread according to one of claims 1 to 5 and 13 to 18, whereby at least two yarn components are intermingled with one another, characterized in that for each yarn component a poly-trimethylene-terephthalate-fiber is choosen, having

    a) an elongation at break between 25 % and 85 %,

    b) an elastic tensile elongation of between 30 % and 95 % of the elongation, determined by a measuring strength, corresponding to 70 % of the absolute strength of the respective sewing thread, and

    c) that the intermingled yarn is subjected to a hydrothermal treatment.
22. The method according to claim 21, characterized in that two multifile yarn components are intermingled with one another and in that the first yarn component forming the core of the yarn is fed with an overfeed between 2 % and 15 % and the second effect thread component is fed to the intermingling step with an overfeed between 5 % and 40 %.
23. The method according to claim 21, characterized in that a multifile poly-trimethylene-terephthalate fiber or a spun yarn of poly-trimethylene-terephthalate fibers is selected as the poly-trimethylene-terephthalate-fiber.
24. The method according to one of claims 19 to 23, characterized in that as hydrothermal treatment a treatment is carried out in an aqueous liquor at an effective - temperature of between 120 °C and 200 °C.
25. The method according to claim 24, characterized in that prior to the hydrothermal treatment the yarn is wound onto a bobbin, and that the bobbin wound with the yarn is subjected to treatment in the aqueous liquor as hydrothermal treatment.
26. The method according to one of claims 19 to 25, characterized in that the yarn is dyed and/or lubricated after the hydrothermal treatment, and that the dyed and/or lubricated yarn is drawn.
27. The method according to claim 26, characterized in that the dyed and/or lubricated yarn is drawn at a temperature between ambient temperature and 180 °C.
28. The method according to claim 26 or 27, characterized in that the dyed and/or lubricated yarn is drawn with a tension between 0,2 cN/dtex to 1,5 cN/dtex, preferably between 0,3 cN/dtex and 1 cN/dtex.
29. The use of the sewing thread according to one of claims 1 to 18 as well as of the sewing thread produced according to one of claims 19 to 28 for making double lockstitch seams in elastic ready-made articles.
30. The use of the sewing thread according to one of claims 1 to 18 as well as of the sewing thread produced according to one of claims 19 to 28 as embroidery yarn for making embroidery patterns, in particular for making three-dimensional, graphic embroidery patterns.