EP0919649B1 - Sewing yarn made of synthetic multifilaments as well as method to produce such a sewing yarn - Google Patents

Description

The present invention relates to a sewing thread made of synthetic Multifilaments with the features of the generic term of Claim 1 and a method for producing a such sewing thread.

It is known to produce sewing threads of different designs. For example, DE 43 05 829 A a sewing thread that consists of at least two multifilament individual components, whereby these two multifilament single components under training of the finished sewing thread are intermingled. This creates a sewing thread, the required thread closure is achieved in that individual thread sections the sheath yarn component with the multifilament core yarn component are confused.

In addition to the air-entangled sewing threads described above known for example from DE 42 15 212 A core yarns, wherein with such a core yarn a soul material of at least is wound in a sheath yarn. In other words The sheath yarn component largely covers the core material from, to create the finished sewing thread then preferably two to four core yarns of this type with one another be twisted.

In addition, sewing threads can also be constructed as filament threads his. First, multifilament skeins of thread are created the corresponding pre-twists are made by twisting, in particular two to three pre-twists then under training of the finished thread is twisted again be, as described in DE 42 15 016 A. is. Due to the double twist, one of these has Filament has a high tenacity, but it has the disadvantage that the production of such a filament is very expensive, especially since both the pre-twisting as well as the final twisting only at relatively low production speeds can be carried out.

GB-A-0 950 339 is a further development of the previously described Filamentzwirnes known, this known Filament additionally has a coating. This coating is used to add the finished yarn stabilize so that when unwinding this yarn from a corresponding bobbin by twisting the partial yarn strands restoring forces do not become an undesirable Twist and loop formation.

In addition to the prior art listed above still refer to EP-A-0 080 346 and JP-A-02277841, which also describe coated yarns, whereby however, the basic construction of these coated yarns intermingled filaments, which is therefore not are aligned parallel to each other.

The present invention is based on the object To provide sewing thread, especially good ones Sewing properties can be produced relatively inexpensively.

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

The sewing thread according to the invention, which is made of synthetic multifilaments, in particular from polyamide and / or polyester multifilaments, consists of at least two strands of this synthetic multifilaments. Here are in each of these at least two strands that form the respective strand Multifilaments aligned in parallel, the minimum two strands are twisted together. Furthermore are then with each other in the sewing thread according to the invention twisted strands covered with a polymer coating, which completely clumsy the surface of the sewing gamer. In other words, the invention differs Sewing thread from the known filament thread in that in the sewing thread according to the invention, the forming the sewing thread Strands has only those multifilaments that are parallel to each other run so that the individual multifilaments one of each strand are not twisted. Furthermore, that is sewing thread according to the invention still with the polymeric coating coated, this polymeric coating on the one hand the required thread closure in the sewing thread according to the invention causes and on the other hand prevents that during sewing operations due to the high mechanical and thermal loads on individual filaments of the strands to be damaged.

The sewing thread according to the invention has a number of advantages on. So it should first be noted that the invention Sewing thread compared to a sewing thread much cheaper is to be produced, since the pre-twisting described above the yarn components forming the twine can be omitted.

A desired one can also be used in the sewing thread according to the invention Set the bending stiffness, the relevant Flexural rigidity through a variation in the chemical structure on the surface of the sewing thread according to the invention arranged coating to the respective requirements can be adjusted when sewing. Furthermore, it has sewing thread according to the invention compared to one of a identical starting material produced sewing thread Surprisingly, a higher strength and in particular a higher performance, which is particularly the case with critical sewing thread operations, for example at multidirectional sewing, particularly noticeable. Further gives the sewing thread according to the invention in comparison to one Sewing thread with the same material use a between about 2% and about 10% longer length, which is attributed to that the strands forming the sewing thread according to the invention Filaments are not pre-twisted together.

In a first embodiment of the sewing thread according to the invention it has two strands that twist together are. Such an embodiment can be used here produce particularly inexpensive, this embodiment the sewing thread according to the invention additionally the advantages has, as described above.

Depending on the respective area of application as well as on the Surface of the twisted strands provided polymeric coating is aimed at the invention Yarn the number of turns / m required to connect the minimum two twisted strands in the inventive Sewing thread are provided. Preferably at the at least two strands with the sewing thread according to the invention 2 to 500 turns / m, in particular with 250 to 350 turns / m, wound together, it was found that sewing threads according to the invention with the aforementioned windings deliver particularly good sewing results. Press this is characterized, for example, by the fact that such embodiments of the sewing thread according to the invention with an optimized Flexural rigidity does not tend to undesirable postponements.

Basically, it should be noted for the sewing thread according to the invention that that the at least two strands forming the sewing thread, who are related to each other regarding their title, their Filament number and / or their filament material different could be. However, it is particularly suitable if this at least two strands are identical, i.e. have both the same titer and the same number of filaments and consist of the same filament material.

Such an embodiment has particularly good sewing properties of the sewing thread according to the invention, in which everyone Strand a titer between 49 dtex and 1,300 dtex, preferably between 76 dtex and 940 dtex. Thus, in particular such an embodiment of the invention Sewing thread if it consists of two twisted strands there is a total titre between 98 dtex and 2,600 dtex, preferably between 192 dtex and 1,880 dtex.

Regarding the number of filaments of each strand, it should be noted that in particular the strands are selected so that each strand has between 16 individual filaments and 600 individual filaments, preferably between 24 individual filaments and 400 Individual filaments. Accordingly, varies in particular in such an embodiment of the invention Sewing thread in which this consists of two strands, the total number of filaments of the sewing thread according to the invention between 32nd Single filaments and 120 single filaments, especially between 48 single filaments and 80 single filaments.

To the sewing operations listed above, especially that multidirectional sewing, with good results, i.e. without thread break and at a high speed of up to 7,000 Stitches / min to be able to perform, preferably varies at the overall strength of the sewing thread according to the sewing thread according to the invention between 35 cN / tex and 69 cN / tex, especially between 40 cN / tex and 55 cN / tex.

It has already been stated at the beginning that the sewing thread according to the invention consists of strands of synthetic multifilaments. Here, the term synthetic multifilaments preferably includes polyester multifilaments, in particular polyethylene terephthalate multifilaments, and also polyamide multifilaments, a particularly suitable embodiment of the sewing thread according to the invention having strands consisting of polyamide 6.6 and / or polyamide 4.6.
Of course, however, it is also possible to produce such an embodiment of the sewing thread according to the invention, in which there is one strand of polyester multifilaments and a second strand of polyamide multifilaments, in particular of polyethylene terephthalate filaments and polyamide 6.6 multifilaments, such an embodiment of the Sewing thread according to the invention is provided when special sewing operations require such a combination of materials.

Basically, with regard to the on the invention Sewing thread arranged coating to hold that this Encloses the entire surface of the sewing thread. Here should such a coating if possible no cracks, craters or have other injuries, because in particular with relatively brittle coatings there is a risk that the coating during further processing of the sewing thread, especially when sewing, further breaks, tears open or splinters off, so that such sewing thread problems processing. Preferably on the surface of the twisted at least two strands one Coating arranged, which is relatively elastic. In particular such a coating then has a thickness between 1 mm and 0.0003 mm, preferably between 0.5 mm and 0.05 mm.

Regarding the number of copies on the sewing thread according to the invention arranged coating is to be noted that particularly good sewing results with the sewing thread according to the invention can be achieved if the coating in one Circulation between 0.2% and 18% by weight, especially in a circulation between 4% and 10% by weight, based on each on the ready-to-use sewing thread, on the inventive Sewing thread is present.

To the friction and / or sliding behavior of the invention Further improvement of sewing thread sees a further development of the sewing thread according to the invention before that on the surface of the Coating is additionally arranged a preparation, a natural preparation especially for this and / or synthetic wax, a polyalkylene oxide compound, in particular a polyethylene glycol, a silicone oil and / or a derivative of the aforementioned compounds is provided becomes. Such a preparation additionally protects that sewing thread according to the invention and can cause undesirable embrittlement counteract the coating.

Basically, with regard to the on the invention Sewing thread to hold existing coating that it is this is such a polymeric coating, on the one hand the required mechanical and thermal stability has and on the other hand the thread closure in the invention Sewing thread promotes or largely effects. Under the term yarn closure is understood to mean that the Coating even with a multiple deflection of the invention Sewing threads in particular the postponement of training Capillaries prevented, so that the invention Sewing thread can be processed as a largely compact thread can.

Specifically regarding the chemical structure of the coating, that this coating is polymers on the Based on polyvinyl alcohols, polyvinyl alcohol derivatives, polyacrylic acids, Polyacrylic acid derivatives, polyesters and / or Can act polyhalogen compounds. Particularly good results can with respect to the sewing thread according to the invention of the sewing behavior if this is used as a coating a polymer is selected that is chemically based a polyurethane, a modified polyurethane and / or a copolymer based on a polyurethane and another polymerizable or oligomerizable substance is constructed. Here it has been shown that in particular a copolymer containing a polyurethane and one Polyester, excellent sewing properties to the invention Sewing thread gives.

If the sewing thread according to the invention is a dyed one Sewing thread or a raw white sewing thread, so it offers assume that the provided on the sewing thread according to the invention Coating a colorless, transparent coating is.

In a particularly suitable embodiment of the invention However, sewing thread is the one on the invention Colored coating provided for sewing thread. Here will such a colored coating especially for such Sewing threads are used, which are used for rows, so that then the non-dyed sewing thread according to the invention accordingly be color-coded using the colored coating can. This makes it possible in a particularly simple manner after processing the sewing thread, which is about the related Coating is colored, this for rows used sewing thread again from the made-up garment to remove so that such a sewing thread in the Manufacturing brings considerable advantages. This embodiment can also of the sewing thread according to the invention for confection of parts used in which several layers sewn with different sewing threads, so that in Then simply ascertained as part of a quality control can be, which location with which, different about the coating is sewn onto dyed sewing threads. Such Control is, for example, for security-relevant Parts, especially seat belts or airbags, are desirable and beneficial.

To enable the previously mentioned colored coating, it is ideal for colorless, transparent coatings to add at least one color pigment to the coating, so that the coating next to the polymeric coating substance additionally at least a color pigment, in particular an inorganic color pigment, having.

The present invention further relates to a method for the production of the previously described invention Sewing thread.

The inventive method for producing the previously described Sewing thread provides that at least two skeins made of synthetic multifilaments aligned in parallel, in particular polyamide and / or polyester multifilaments, be wound together, after which the twisted together at least two strands with a polymer Coating that completely closes the surface of the sewing thread. After that it will be with the polymer coating applied sewing thread one Subjected to heat treatment, causing the coating to dry and / or is polymerized or condensed.

The term polymer coating covers all coatings which are already polymerized, so accordingly the heat treatment merely involves drying the coating causes, as well as such coatings that are polymerizable or contain oligomerizable constituents or consist of this, so that the heat treatment is not just a Drying, but also condensation or Polymerize and thus the formation of the corresponding brings about polymeric coating.

The method according to the invention points towards the beginning State of the art listed and in particular compared to known twisting process the advantage that it is relatively simple and can be carried out inexpensively. Furthermore let such sewing threads according to the inventive method produce as described above, so that the invention The method in the sewing thread according to the invention has advantages set forth accordingly.

Regarding those used in the method according to the invention and at least two strands of the to be twisted together Multifilament yarns apply the same designs as they do are set out above in the sewing thread according to the invention. Of therefore, to avoid repetition on this Reference made to the sewing thread according to the invention.

As already stated above, this is used in the invention Process envisaged heat treatment either drying, provided the coating itself is already polymeric or drying and condensation or polymerization, if the selected coating polymerizes as a result, is oligomerized and / or crosslinked. Of course such drying and condensation or carry out polymerization by means of a single heat treatment, however, an advantageous development of the invention The procedure provides that this with the Coated and twisted strands first dried and then condensed or polymerized become. Such a stepwise procedure has the advantage on that hereby the yarn according to the invention with a such coating can be provided as far as possible is free from damage to the polymeric coating.

Regarding the temperature during drying is to the invention Procedure to record that this temperature on the one hand according to the number of runs of the coating and on the other hand according to the particular solvent in which the polymer Coating is loosened. Preferably varies the drying temperature in the process according to the invention between 80 ° C and 170 ° C, especially between 100 ° C and 150 ° C, while the drying time is preferred between 0.5 s and 10 s, in particular between 3 s and 8 s.

The condensation temperature to be used in the process according to the invention or polymerization temperature depends also after the selected coating, the one used Solvent and the amount of the coating. Preferably varies in the method according to the invention this temperature between 130 ° C and 240 ° C, in particular between 155 ° C and 190 ° C, with the corresponding residence times during the condensation or polymerization in particular between 0.1 s and 10 s, preferably between 1 s and 3 s, lie.

As already stated above for the yarn according to the invention such coatings are used in the process according to the invention selected as these are generally listed there are. In particular, however, in the method according to the invention an oligomerizable and / or polymerizable polyurethane, an oligomerizable and / or polymerizable Polyurethane derivative and / or an oligomerizable and / or polymerizable copolymer made from a polyurethane and a polyester selected, in addition to the previously specific mentioned coatings still have a suitable crosslinking agent can be three-dimensionally networked, so that a particularly strong adhesion of the coating to each other twisted skeins of thread is reached.

If the selected coating is soluble in water, so is in the process of the invention alone environmental aspects, the respective selected coating taken up in water, preferably dissolved in water, and via a suitable application unit to each other twisted skeins of thread applied. Particularly suitable under the point of view of a higher production speed are such developments of the method according to the invention, where the selected coating is made of an organic Solvent or a mixture of solvents, in particular from a lower alcohol and / or a halogenated Hydrocarbon on the twisted at least two strands are applied. Additionally points such a development of the method according to the invention still have the advantage that the surface of a so applied Coating is largely closed and thus does not have the craters or cracks previously described.

With regard to the application of the coating in the invention In principle, any order procedure can be used be applied, which is suitable, the coating evenly on the at least two twisted skeins of thread applied. Here is particularly in the inventive Method preferred a dip-squeeze method, by varying the roller hardness of the used here Squeezing mechanism an even distribution of the coating also across the cross-section of the at least two, with each other twisted skeins of thread is guaranteed.

In a further embodiment of the invention Process applied the coating from an aqueous system, so it is a good idea to apply it aqueous coating, which is a dispersion or solution, the known minimal application techniques apply, in particular a Spraying or foaming are to be named.

As already stated above, all of the Developments of the method according to the invention, in which cross-linking of the coating is desired, the coating added a suitable cross-linking agent, so that thereby a particularly permanent fixation the coating on the yarn is reached. Of course however, it is also possible to use such a crosslinking agent in a separate operation on the minimum to apply two twisted skeins of thread, whereby either this separate application of the cross-linking agent before or after applying the coating can.

Another embodiment of the method according to the invention provides that the twisted strands before the Applying the coating of a physical and / or chemical Treatment to be subjected to, by this physical and / or chemical treatment then the surface of the multifilaments forming the strands roughened and / or is microstructured. This embodiment variant of the invention The process then leads to such coated Yarns in which the coating is very durable and firm the surface of the yarn and especially the surface the outer multifilaments of the strands are fixed, thereby fixing the durability and durability of this Coating against thermal and mechanical loads of the sewing thread is particularly high in subsequent processes.

Such roughening or microstructuring of the surface the multifilaments forming the strands can be chemically, for example by appropriate chemicals, or in particular be brought about physically, one particularly advantageous, easy to carry out training of the method according to the invention here is a low-temperature plasma treatment and / or provides corona treatment.

As already stated above, in the case of the invention Process the adhesion of the coating to the surface the multifilament yarns forming the strands too be carried out by chemical treatment. in this connection is on the single strands or on the twisted together Strands of a suitable chemical, for example at Polyester multifilaments a lye, applied, so that subsequently after a thermal treatment the surface these multifilaments are roughened or microstructured accordingly is.

Likewise, with a suitable further development of the invention Process the chemical treatment through it performed that the strands with a suitable Swelling agents are brought into contact, the swelling agent usually in addition to roughening and / or microstructuring in particular causes the polymeric coating in the amorphous regions of the fiber polymers forming the multifilaments penetrates and is thus firmly anchored here. With in other words, the coating is fixed here not only on the surface of the multifilaments but additionally in the actual fiber polymer, so that such fixed coatings are particularly durable.

Regarding the heat treatment described above to note that for drying preferably in the inventive method an IR (infrared) and / or HQ (high frequency) drying is used while the Condensation or the polymerization of the coating in particular also be carried out under UV radiation can.

The sewing thread according to the invention is described below using a Exemplary embodiment in connection with the drawing explained. Here, the only figure of the drawing gives a schematic and enlarges an embodiment of the invention Sewing thread again.

In the figure, the sewing thread is denoted by a total of 1, wherein the sewing thread from two twisted strands exists, which are numbered 2 and 3.

Each strand has a plurality of aligned in parallel Multifilaments on, in strand No. 2 only for example two of these multifilaments, designated 4 and 5 and in strand no. 3 also only two with an example 6 and 7 designated multifilaments are shown.

Regarding the figure shown in the figure, it should be noted that this figure is only a schematic figure, the axial and radial distance between the both strands 2 and 3 accordingly for better illustration was enlarged. In reality, the two strands are 2 and 3 close to each other, so that the numbered 8 in the figure Indeed, there is no free space between the strands is available.

As can also be seen in the schematic illustration of the figure the neckline of the sewing thread shows three turns 9, 10 and 11, wherein at the winding point 9 to 11 the Cross strands 2 and 3 in such a way that alternately the Strands are above and below the image planes and mutually covered by the other strand are.

Furthermore, the sewing thread 1 shown in the figure is included a schematically drawn polymer coating 12 Mistake. This polymeric coating 12 removes them together twisted strands 2 and 3 like a sheath so that accordingly the twisted strands 2 and 3 are embedded in the coating 12. Additionally is on a wax-like preparation on the surface of the coating 12 13 arranged, on the one hand an increase in elasticity the coating and on the other hand an optimization the friction and sliding behavior of the sewing thread 1 causes.

The coating 12 shown in the figure consists of a copolymer of a polyurethane with a polyester.

Claims (25)

1. A Sewing yarn consisting of synthetical multifilaments, particularly of polyamide and/or of polyester multifilaments, characterised in that at least two strings (2, 3) of multifilaments (4, 5; 6, 7) being parallely arranged are twisted with each other and that the strings (2, 3) being twisted with each other are provided with a polymeric coating (12) under the formation of the sewing yarn (1), whereby the coating (12) covers completely the surface of the sewing yarn (1).
2. The sewing yarn according to claim 1, characterised in that two strings (2, 3) of the multifilaments (4, 5; 6, 7) are twisted with each other.
3. The sewing yarn according to claim 1 or 2, characterised in that the strings (2, 3) are twisted with each other by 2 to 500 turns/m, particularly 250 to 350 turns/m.
4. The sewing yarn according to one of the preceding claims, characterised in that each string (2, 3) comprises a titre of between 49 dtex and 1.300 dtex, preferably between 76 dtex and 940 dtex.
5. The sewing yarn according to one of the preceding claims, characterised in that each string (2, 3) has a number of filaments of between 16 and 600 single filaments, preferably between 24 and 400 single filaments.
6. The sewing yarn according to one of the preceding claims, characterised in that the sewing yarn (1) has a strength of between 35 cN/tex and 69 cN/tex, preferably between 40 cN/tex and 55 cN/tex.
7. The sewing yarn according to one of the preceding claims, characterised in that each string (2, 3) of the sewing yarn (1) consists of polyamide 6.6 and/or of polyamide 4.6.
8. The sewing yarn according to one of the preceding claims, characterised in that the coating (12) has a thickness of between 1 mm and 0,0003 mm, preferably between 0,5 mm and 0,05 mm.
9. The sewing yarn according to one of the preceding claims, characterised in that the coating (12) is between 0,2 % by weight and 18 % by weight, preferably between 4 % and 10 % by weight, relative to the sewing yarn (1) ready to use.
10. The sewing yarn according to one of the preceding claims, characterised in that the coating (12) is a polymer basing on a polyurethane and/or on a modified polyurethane.
11. The sewing yarn according to one of the preceding claims, characterised in that the coating (12) is coloured.
12. The sewing yarn according to claim 11, characterised in that at least one coloured pigment is added to the coating (12).
13. A method for the manufacturing of a sewing yarn according to one of the claims 1 to 12, characterised in that at least two strings (2, 3) of parallely arranged synthetical multifilaments (4, 5; 6, 7) are twisted with each other, that the strings (2, 3) being twisted with each other are provided with a polymeric coating (12), which covers completely the surface of the sewing yarn (1), and that hereafter the sewing yarn (1) is submitted to a heat treatment.
14. The method according to claim 13, characterised in that the strings (2, 3) of multifilaments (4, 5; 6, 7) being twisted with each other are provided with a coating (12) and that as heat treatment the strings (2, 3) being twisted with each other and being provided with the coating (12) are hereafter firstly dried and then cured.
15. The method according to claim 14, characterised in that the strings (2, 3) being twisted with each other and being provided with the coating (12) are dried at a temperature of between 80 °C and 170 °C, preferably between 100 °C and 150 °C.
16. The method according to claim 15, characterised in that strings (2, 3) being twisted with each other and being provided with the coating (12) are dried for a duration time of between 0,1 s and 10 s, preferably between 3 s and 8 s.
17. The method according to one of the claims 13 to 16, characterised in that the strings (2, 3) being twisted with each other and being provided with the coating (12) are condensed at a temperature of between 130 °C and 240 °C.
18. The method according to claim 17, characterised in that the strings (2, 3) being twisted with each other and being provided with the coating (12) are cured for a duration time of between 0,1 s and 10 s, preferably between 1 s and 3 s.
19. The method according to one of the claims 13 to 18, characterised in that an oligomerisable and/or polymerisable polyurethane and/or an oligomerisable and/or polymerisable polyurethane derivative is selected as coating (12).
20. The method according to claim 19, characterised in that the coating (12) is applied out of water and/or out of an organic solvent, respectively solvent mixture.
21. The method according to one of the claims 13 to 20, characterised in that a minimum applying technique is applied to deposit the coating (12).
22. The method according to one of the claims 13 to 21, characterised in that a cross linking agent is added to the coating (12).
23. The method according to one of the claims 13 to 22, characterised in that the strings (2, 3) being twisted with each other are submitted to a chemical and/or physical treatment before being coated, whereby by this treatment the surface of the multifilaments (4, 5; 6, 7) forming the strings (2, 3) is roughened and/or micro-structured.
24. The method according to the claim 23, characterised in that the treatment is a low temperature plasma treatment and/or a corona treatment.
25. The method according to claim 23, characterised in that a swelling agent is added to the surface of the strings (2, 3) for the chemical treatment of the single strings (2, 3) being twisted with each other.

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