RU2402649C1 - Heat resistant sewing thread and method of its manufacturing - Google Patents

Abstract

FIELD: textile, paper.

SUBSTANCE: heat resistant sewing thread contains at least two twisted reinforced threads and preparing composition. Each reinforced thread includes core and braiding. Core consists of one or two complex threads from heat resistant non-thermoplastic paraamide threads with decay temperature over 500°, with permanent strain after rupture 2.5-5.0% and strength of 150-245 gs/tex. Braiding is made of thermomelting and heat shrinkable polyester fibres with melt temperature of 240-260°, with zero strength temperature of 260-280°, with heat shrinkage prior to fibre melt 38-44%, fibre length of 35-40 mm, with linear density of 0.12-0.17 tex. Share of coverage with polyester fibres equals 33.7-51.6 wt % of finished thread. Method for production of heat resistant sewing thread includes formation of at least two reinforced threads, their cabling, twisting into twisted thread, thermal fixation, application of preparing composition. At the same time, during formation of reinforced thread, polyester fibres are thinned with drawing multiple to 24-32 into broken thread of linear density of 6.4-13.4 tex, in zone of twisting triangle, core is pulled with force that exceeds force of broken thread drawing 2.2 times.

EFFECT: invention provides for increased strength and heat resistance of sewing threads with preservation of tension, resistance to bends and sewing properties.

4 cl, 4 dwg, 5 tbl

Description

The invention relates to the textile industry and relates to heat-resistant sewing threads that can be used for sewing suits of firefighters, metallurgical workers, welders, which will significantly expand the assortment group of heat-resistant threads that provide consumer properties of clothing.

Heat-resistant sewing threads are known, 100% consisting of complex polyaramide threads (CBM, Rusar), according to TU 8147-042-31094986-2004 “Heat-resistant sewing threads”, which have high tensile strength, high heat, heat, and fire resistance ( To _I -35-38). But due to the high modularity, these threads are stiff, low extensible, have a large loss of bending strength (in particular, in the loop), have insufficient resistance to UV rays and light weather, and have insufficiently good tailoring properties.

To eliminate the above disadvantages, it is known to use two-component reinforced threads.

Known "Twisted sewing thread" according to patent RU 2066355 C1, cl.6. D02G 3/46 from 1993.04.12, publ. 1996.09.10. Inventors: Titovets V.A., Shchitnikova E.M., Bodunov V.L., Shalina M.N., Grigoryeva M.P., Zaitseva G.E. (PNK named after S.M. Kirov), containing two or more single reinforced yarns twisted together, formed on a ring spinning machine from a PE core and a braid from high-modulus viscose siblon fibers.

The well-known "Method for producing a twisted reinforced thread" according to patent RU 2073754 C1, cl.6. D02G 3/36 of 1993.11.18, publ. 1997.02.20. Inventors: Ivanova M.I., Ivanov G.N., Kaplun Yu.P., Rasskazova N.A., Grigoriev V.N., Nessirio TB (AOOT Sovetskaya Zvezda, St. Petersburg State University), according to which single reinforced yarns are formed on a spinning machine by wrapping a polyester core yarn with a braid of finite length fibers, rewind single reinforced yarns, cane and twist, characterized in that before forming single reinforced yarns, their cotton fibers the braids are treated with non-conductive, increasing the adhesion of the braid fibers with a core thread composition and produce the final torsion.

The disadvantage of threads according to the patents RU 2066355 C1 and RU 2073754 C1 is low heat resistance, insufficient strength at elevated temperatures, low oxygen index (K _And = 23), they are not suitable for sewing clothes and other products that protect from high temperatures, heat, fire, since the core and braid consist of heat-resistant PE or rayon staple and PE multifilament yarns.

The closest to the solution of the problem is "Sewing thread and method for its production", according to patent RU 2004643 C1, cl. 5 D02G 3/46 from 01/31/1991, publ. 12/15/1993, bull. No. 45-46. Inventors: Bedenko V.E., Grigoryeva S.N., Belyakova TB, Alekseenko I.E., Fedotova T.F. (Research Institute of Textile Industry, St. Petersburg).

Heat and light resistant sewing thread according to patent 2004643, made with a preparation composition and containing at least two reinforced threads twisted with each other, having a core in the form of a complex polyester (PE), polyacrylonitrile (PAN) or phenylone (FN) thread with a tensile elongation not less than 8% and with a strength of 35-75 gf / tex and coated with staple synthetic fibers, representing a sliver of heat and light-resistant phenylon fibers with a length of 55-120 mm, a linear density of 0.22-0.45 tex and with tensile elongation equal to 8-35%, with the share the core in each reinforced thread is 33-61 wt.%.

The mechanical and thermomechanical strength of these threads does not provide good quality when sewing and operating products that protect against heat and fire.

The core of polyester (PE), polyacrylonitrile (PAN) and phenylone (FN) provides the strength of the finished thread no more than 25-40 gf / tex. Due to the thermoplasticity of the core of polyetherphenyl (FL), polyacrylonitrile phenyl (F) and the low strength of phenyl phenophenone (F) threads, the finished threads do not withstand the action of heat during the operation of thermal protective products (K _And not more than 25). A phenylon braid with a fiber strength of about 50 gf / tex in an amount of 39-67 wt.% Does not produce a significant increase in strength and heat resistance, but an increase in resistance to UV rays and light weather is achieved. The strength of stitches for one tex thread is not more than 0.027-0.048 kgf / 1sv. / 1 tex.

The technical result of the claimed invention is the elimination of the above disadvantages, namely increasing the strength and heat resistance of sewing threads, including when exposed to heat and fire while maintaining tensile properties, resistance to bending and sewing properties.

The task is achieved in that in a heat-resistant sewing thread made with a preparation composition and containing at least two twisted reinforced threads having a core in the form of a complex thread and a coating of staple synthetic fibers, the complex core thread is made of heat-resistant non-thermoplastic with a decomposition temperature in excess of 500 ° With para-aramid yarns with a tensile elongation of 2.5-5.0% and strength from 150 to 245 gf / tex, and the braid is made of heat-fusible and heat-shrinkable polyester fibers with a melting temperature lengths of 240-260 ° C, with a temperature of zero strength 260-280 ° C and heat shrinkage before melting the fibers 38-44%, with a linear fiber density of 0.12-0.17 tex, while the proportion of coating from staple fibers is 33.7 -51.6 wt.% Of the finished yarn.

The structure of the inventive yarn is presented in figure 1, where

1 - appearance of a reinforced sewing thread;

2 - reinforced threads (reinforced yarn);

3 - core of a complex thread;

4 - braid sliver (core coating).

The task is achieved with improved technical results in the following embodiment.

Heat-resistant sewing thread, characterized in that in order to increase strength, heat resistance, bending and sewing properties due to uniform durable coating, the core contains two complex heat-resistant non-thermoplastic para-aramid threads SVM, and the core coating consists of two slippers from two rovings made of thermoplastic and heat-shrink polyester fibers.

The structure of the thread is shown in figure 2, where

1 - appearance of a reinforced sewing thread;

2 - reinforced threads (reinforced yarn);

3 - core, consisting of two complex threads;

4 - braid, consisting of two slippers from two rovings.

The novelty of the inventive heat-resistant threads, shown in figures 1 and 2, is the combination of a heat-resistant non-thermoplastic para-aramid core of one or two complex threads with a heat-shrinkable heat-shrinkable polyester staple consisting of one or two slippers from two rovings, covering the core and protecting the core from heat, fire and other influences during the operation of products.

Performing protective functions, the claimed combination of fibers gives the threads increased elongation (elasticity), increased flexural strength, and improved sewing properties.

For a better understanding of the essence of the proposed solutions, we present tables 1-5 and figure 1-4, confirming the results of examples of actual implementation of the invention.

The inventive heat-resistant sewing threads (table 4, var. 1-7) were developed using the inventive method for their production on standard equipment of cotton production under the conditions of OAO Petroleum Thread Research Institute (St. Petersburg).

In options 1-7 of the inventive threads (table 4), consisting of 2, 3 and 4 additions with a linear density of 39.3 to 83.4 tex, with a polyester braid content of 33.7 to 51.6 wt.% From the finished thread, the relative tensile load of the threads 105-149.2 gf / tex was obtained, the tensile elongation was 6.3-6.9%.

Table 4 shows that the introduction of a braid in the form of a sliver made of PE fibers increased the elongation (yarn var. 1-7) to 6.3-6.9%, i.e. by 19.6-35.3% or by 27.1-43.8% against the rupture rate of threads, 100% consisting of CBM or Rusar threads, respectively (var. 8, 9). The resistance of the threads (var. 1-7) to bending (the percentage of maintaining the strength of the threads in the loop) with the introduction of a braid of polyester fibers increased by 13.2-16.6% and by 16.2-19.7% to threads, by 100 % consisting of CBM and Rusar threads, respectively (var. 8, 9). This increases the strength of the threads in the seams (table 5).

Figure 3 photographed lines on fabric (5) with a metallized coating (6), made by the inventive threads (var. 3). The lines were exposed to fire with a temperature of about 750 ° C from the gas burner for one minute. The lines retained their integrity (see pos. 7). After a special purpose for the analysis of cutting the shuttle thread and separating the needle thread from the surface of the fabric, the pieces of the shuttle thread were glued to the needle thread and stably held on it due to the thermoplasticity of the PE braid and the heat resistance of the aramid core (see pos. 8).

With high heating of the threads (over 260 ° C) in the joints, the braid, having zero strength, becomes a molten mass, envelops and absorbs into a heat-resistant non-thermoplastic para-aramid core, strengthens it, protects against fire. Thanks to heat shrinkage and zero strength, the molten mass of the braid under the influence of fire and heat is easily absorbed into the core and partially “flows” from the more heated area between the punctures of the needle to the less heated areas in the weave, strengthening it.

Figure 3 (item 9) shows that the sliver of thermoplastic and heat-shrinkable fibers (melting point 260 ° C), being melted, tightly fits the aramid core thread, is absorbed into it, giving it strength and protecting it from fire and heat. Such areas are visible as blackened areas on the needle thread (key 9).

A method for producing heat and light resistant sewing thread according to patent 2004643, according to which at least two reinforced threads are formed by coating the core in the form of polyacrylonitrile, polyester or phenyl complex yarn with a coating of staple heat and light resistant phenylon fibers 55-120 mm long, linear density 0.22-0.45 tex and with a tensile elongation of 8-35%, they reinforce the threads, twist them into a twisted thread, apply a preparation composition to it, while the sliver is thinned with an extract equal to 10-22, when connecting the sliver to the set The latter is subjected to stretching in the zone of the torsion triangle with a force exceeding the pulling force of the sliver by 1.5-2 times.

This method according to patent 2004643 does not allow to obtain a sewing thread with mechanical and thermomechanical strength, providing good quality when sewing and operating products that protect against the effects of heat and fire. The core of polyester (PE), polyacrylonitrile (PAN) and phenylone (FN) is not heat-resistant and provides a strength of no more than 25-40 gf / tex.

The 2004643 prototype braid of a phenylone fiber sliver with a strength of about 50 gf / tex, with a linear density of 0.22-0.45 tex, with a length of 55-120 mm and with a tensile elongation of 8-35% is very rough, low plastic, not allowing evenly cover and protect the core of the thread when exposed to heat.

The technical result of the proposed method of obtaining is to eliminate the above disadvantages, namely due to a different combination of components, due to the uniform distribution of the braid on the core, the strength and heat resistance of sewing threads are increased under normal conditions of use and when exposed to heat and fire, while maintaining tensile, bending and sewing properties.

In the method for producing a heat-resistant sewing thread, according to which at least two reinforced threads are formed by applying to the core in the form of complex threads coated with staple synthetic fibers, reinforced threads are pulled, twisted into a twisted thread, heat-fixed, applied to it with a preparation composition, when forming each reinforced yarn roving of thermoplastic and heat-shrinkable with a melting point of 240-260 ° C, with a temperature of zero strength 260-280 ° C and with heat shrinkage before melting the fibers 38-44% floor ether fibers with a length of 35-40 mm, a linear density of 0.12-0.17 tex are thinned with an extract multiple of 24-32 into a sliver of a linear density of 6.4-13.4 tex, comprising 51-106 wt.% of the linear density core, after which it is connected to a heat-resistant non-thermoplastic core containing one or two complex threads of heat-resistant non-thermoplastic para-aramid threads with a decomposition temperature of more than 500 ° C and twisted to obtain a reinforced thread, while the connection of the sliver with the core is carried out with stretching in the area of the torsion triangle, reinforced thread with a force exceeding 2.2 times the pulling force of the sliver by bending the exhaust roll 90-135 degrees.

A method of obtaining a heat-resistant thread, according to which at least two reinforced threads are formed in the form of complex threads coated with staple synthetic fibers, the reinforced threads are cut, twisted into a twisted thread, thermofixed, a preparation composition is applied to it, characterized in that in order to improve the sewing properties due to the uniform and durable bonding of the braid with the thread (core threads), the sliver is formed of two rovings of thermoplastic and heat-shrink staple of polyester fibers, connected to the cord com in the form of one or two filaments of para-aramid and subjected to twisting with a twist coefficient (α _ave) equal to 34-43, and the reinforced filaments after doubling twist in the opposite direction with a twist equal to (α _cr) 34-47, wherein the ratio of absolute torsions per unit length is taken equal to 1.20: 1.60: 1.

The essence of the proposed methods for producing heat-resistant threads is presented in figure 4, where

10 - bobbin with a thread of a core from para-aramid;

11 - bobbin with roving made of polyester staple;

12 - exhaust device of a spinning machine;

13 - guide for the core thread;

14 - spindle;

4 - sliver from the roving;

15 - torsion zone.

The novelty of the claimed methods for producing heat-resistant threads is a special combination of the parameters of reinforcing threads from heterogeneous properties of thermoplastic PE braid fibers and a core made of heat-resistant high-strength, high-modulus (low-extensible) para-aramid.

To perform protective functions, a braid made of polyester heat-fusible heat-shrinkable fibers must be uniform, close to continuous, covering the surface of the core threads. For this, at the time of formation, the core should be located in the center of the thread and have a shape close to a straight line. The braid, on the contrary, should be located on the surface of the core, cover it, firmly braiding and mating with it, leaving no gaps between adjacent turns.

In the claimed method, this is achieved due to the fact that the braid is close or thinner than the core up to two times, for which the roving on the coil (pos. 11) is thinned with an extract multiple of 24-32 into a sliver (15) of linear density 6.4-13 , 4 tex, component 51-106 wt.% Of the linear density of the core.

The connection of a tensile, thermoplastic sliver with a low-extensible high-modulus core on a bobbin (10) is carried out with the core stretching in the area of the thread torsion triangle with a force exceeding 2.2 times the pulling force of the slipper in the front zone of the exhaust device (12), for which the exhaust exhaust roller the device is bent around the core by 90-135 degrees.

Figure 4 shows how, with the help of the thread guide 13, the envelope angle is controlled.

For a coating that is close to continuous, the sliver should be made of tensile fibers of low linear density, allowing a good distribution on the surface. In the inventive method for producing heat-resistant filament, polyester fibers with a length of 35-40 mm and a linear density of 0.12-0.17 tex are used, i.e. shorter and thinner fibers than the prototype.

To achieve a strong adhesion of the braid with the core, the twist is taken high enough with a coefficient (α _ol ) of 34-43. The best adhesion is achieved in the version of threads with two heat-resistant non-thermoplastic (decomposition temperature over 500 ° C) para-aramid complex threads in the core and with two slippers from two rovings of thermoplastic fiber with a melting point of 240-260 ° C and with heat shrink before the molten fibers 38-44 %

The scheme of using two slippers from two rovings and a core of two aramid threads, with the declared tension in the torsion zone (15), is shown in Fig. 4.

Figure 5 (pos. 16) shows a photograph of threads of reinforced threads formed by two threads (6.3 tex + 6.3 tex) of the core and two slivers (6.7 tex + 6.7 tex) of two rovings (option thread 7).

In Fig. 5 (pos. 17), reinforced threads from reinforced threads formed by one core thread (14.3 tex) and one sliver (13.4 tex) from one roving (thread option 3).

In Fig. 5 (pos. 18) the same as pos. 17, but with a core thread tension of less than 2.2 times the pulling force of the sliver.

In Fig.5 (pos.19) the same as pos.17, but with a share of coverage of staple fiber more than 51.6 wt.%.

Figure 5 (pos. 16 and 17) shows that the sliver of PE fibers is evenly distributed (white PE fiber). Pos. 18 and 19 show the uneven plexus and bare sections of the threads of the aramid core (light brown core fiber). Uneven braiding with bare core sections makes the reinforced thread unsuitable for obtaining high-quality sewing threads (pos. 18, 19).

The inventive threads (var. 1-7), representing a combination of CBM-PE fibers, are, along with threads 100% composed of CBM and Rusar threads (var. 8, 9), refractory materials. When introducing bundles of threads (var. 3) into the fire-heat field, at a temperature of 600-750 ° С, the flame melts the braid, and the core made of polyaramide maintains its integrity and is slowly charred. The duration of maintaining the integrity of the core tow from the onset of heat and heat exposure to the complete destruction of the tow is

600 ° C - 0.5 min,

550 ° C - 1.0 min,

500 ° C - 3.0 min,

450 ° C - 6.0 minutes

400 ° C - 15.0 min,

At 250-300 ° C, the destruction of the threads does not occur for a time of more than 15-20 minutes.

For comparison, we point out that similar bundles of linen, cotton, polyester-cotton and polyester yarns at a temperature of 350 ° C are destroyed within 3 seconds, polyester-phenylone (PL) and phenyl-phenylone (FN) according to patent 2004643 (prototype) are destroyed seconds.

The inventive thread (var. 3) under the influence of a flame and a temperature of 350-400 ° C for one minute maintained a breaking load of more than 50%. At a temperature of 420-460 ° C, the breaking load was 35-40% of the original.

The temperature of the thermal field was controlled using a standard iron-constantan thermocouple.

Assessment of the physical and mechanical properties of threads and threads was carried out according to a standard method in accordance with ASTMD - 204-97 "Test methods for Seving Thread", with GOST 6611.0-73 - GOST 66.11-4-73 "Textile threads. Acceptance rules and test methods ”(ISO 2060-73, ISO 2062-72, ISO 6939-88, ISO 2061: 1995) (Table 1-5).

Torsion claimed thermostable thread with twist count coefficient reinforced filaments (α _ave) equal to 34-43, a reinforced thread after doubling with twists (α _cr) factor of 34-47 at a ratio of absolute twists per unit of length equal to 1.20 -1.60: 1, allows you to get a good balance and good tailoring properties.

The relative breaking load of one seam stitch, calculated per 1 tex of aramid core thread, is 30-64% higher than that of CBM threads, 100% consisting of complex threads (Table 5). Seams using the inventive threads were made on strips of fabric, the breaking load of the seam was determined according to GOST 28073-89.

Sewing properties of the inventive threads (var. 1-7) are shown in Table 5, where the breaking load of the shuttle seam, calculated on the stitch, as well as on one tex of the core thread, is indicated. Thread Var. 1-7 are 1.3-1.64 times stronger than the threads, 100% consisting of CBM threads (version 8), and 2.5-3.5 times stronger than the threads of the prototype (FL, FN, FF).

Table 1 The name of indicators Aramid core threads (CBM) for thread options Var. 1 and var. 7 Var. 2, 3, 4, 5, 6 Linear density tex 6.3 14.3 Breaking load, gs 945 3503 Breaking elongation,% 5,0 2.5 Relative breaking load, gf / tex 150.0 245.0 Decomposition temperature, ° С 510 525

table 2 The name of indicators Polyester staple braid fiber for thread options Var. 1 Var. 2, 3, 4 Var. 7 Var. 5, 6 Linear density tex 0.12 0.13 0.13 0.17 Cutting length mm 35 38 40 38 Breaking elongation,% 21 22 25 22 Relative breaking load, gf / tex 55 61 61 63 Melting point, ° С 240 256 256 260 Temperature of zero strength, ° С 260 275 275 280 Shrinkage before melting fibers,% 44 41 41 38 Linear density of reinforced yarn, tex 19.0 22.2 26.0 27.7

Table 3 The name of indicators Reinforced aramid-polyester yarn for options threads Var. 1 Var. 2, 3, 4 Var. 7 Var. 5, 6 Linear density tex 19.0 tex 22.2 tex 26 tex 27.7 tex Thread structure, tex: core CBM (6.3 + 6.3) SVM-14.3 CBM (6.3 + 6.3) SVM-14.3 braid PE 6.4 PE-7.9 PE (6.7 + 6.7) PE-13.4 Rovnitsa, tex 200 200 200 200 Slipper hood 32,0 25.3 29.9 24.0 Twist (K _ol ), cr / m 850 720 850 780 Twist coefficient (α _ol ) 37.0 33.9 43.3 41.0 Tension in the area of the torsion triangle, sliver / core thread, gf 28/62 32/72 38/85 38/85 The excess tension of the thread over the tension of the sliver in the area of the torsion triangle, krat 2.21 2.25 2.23 2.23 The angle of the envelope of the exhaust roller, degrees 90 ° 90 ° 135 ° 135 ° Ratio of linear sliver density to linear core density 0.51 0.55 1.06 0.94

Table 5 Thread option Thread structure Shuttle breaking load in the calculation Comparison of P _{1sv / tex} with threads 100% consisting of CBM threads (version 8) one seam stitch, kgf the same for 1 tex core thread, kgf (P _1sv ) (P _{1sv / teks} ) one 19 tex × 2 3.02 0,120 1.30 2 22.2 tex × 2 3.45 0.121 1.31 3 22.2 tex × 3 5.31 0.124 1.34 four 22.2 tex × 4 7.69 0.134 1.46 5 27.7 tex × 2 3.83 0.134 1.46 6 27.7 tex × 3 5.83 0.136 1.48 7 26 tex × 3 5.71 0.151 1,64 8 14.3 tex × 2 × 2 5.29 0,092 1,0 FL prototype 58.1 / 20 = 2.9 0.035-0.043 - Fn 52.1 / 20 = 2.6 0.029-0.032 - Ff 66.7 / 20 = 3.3 0.038-0.048 -

Claims (4)

1. Heat-resistant sewing thread made with a preparation and containing at least two twisted reinforced threads having a core in the form of a complex heat-resistant thread and a braid formed by a sliver of staple synthetic fibers, characterized in that the core contains one or two complex threads of heat-resistant non-thermoplastic para-aramid filaments with a decomposition temperature in excess of 500 ° C, with a tensile elongation of 2.5-5.0% and strength from 150 to 245 g / tex, and the braid is made of heat-fusible and heat-shrink polyester in windows with a melting point of 240-260 ° C, with a temperature of zero strength 260-280 ° C, and with heat shrinkage before melting the fibers 38-44%, with a fiber length of 35-40 mm, with a linear density of 0.12-0.17 tex while the proportion of coverage of staple polyester fibers is 33.7-51.6 wt.% of the finished yarn. 2. The heat-resistant sewing thread according to claim 1, characterized in that the core contains two heat-resistant non-thermoplastic para-aramid threads, and the core braid consists of two slippers from two rovings of thermoplastic and heat-shrink polyester fibers. 3. A method of obtaining a heat-resistant sewing thread, according to which at least two reinforced threads are formed by applying a coating of staple synthetic fibers to the core in the form of a complex thread, reinforce the threads, twist them into a twisted thread, heat-fix it, apply a preparation composition that differs the fact that during the formation of each reinforced yarn, the roving is made of thermoplastic and heat-shrinkable polyester fibers with a melting point of 240-260 ° C, with a temperature of zero strength of 260-280 ° C and with heat shrink Reduced by the melting of fibers 38-44%, length 35-40 mm, linear density 0.12-0.17 tex, they are thinned with an extract multiple of 24-32 into a sliver of linear density 6.4-13.4 tex, component 51- 106 wt.% Of the linear density of the core, after which it is connected to a heat-resistant non-thermoplastic core containing one or two complex threads of heat-resistant non-thermoplastic para-aramid threads with a decomposition temperature of more than 500 ° C, and twisted to obtain a reinforced thread, while connecting the sliver with the core carried out with a core stretch in the tray area a torsion golnik of a reinforced thread with a force exceeding 2.2 times the pulling force of the sliver by bending the exhaust roller of the exhaust device by 90-135 °. 4. The method according to claim 3, characterized in that the sliver is formed of two rovings of thermoplastic and heat-shrinkable staple of polyester fibers, connected to the core in the form of para-aramid threads and subjected to torsion with a twist coefficient (α _CR ) equal to 34-43, and reinforced the threads after twisting are twisted in the opposite direction with a twist equal to (α _cr ) 34-47, while the ratio of absolute torsions per unit length is assumed to be 1.20 ÷ 1.60: 1.

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