RU219662U1 - CORD FABRIC HYBRID IMPREGNATED - Google Patents

Abstract

The utility model relates to the textile industry and relates to a cord fabric used to reinforce the carcass of pneumatic multilayer tires of radial and diagonal designs, in particular large truck tires and other tires with increased load. The technical result of the proposed utility model is to improve the adhesive properties of the fabric. Hybrid cord fabric impregnated with a mixture based on vinylpyridine latex and formed on a basis of twisted, stretched threads of two polymers of polyamide 6,6 and polyamide 6, threads of 140 tex of polyamide 6,6 and an assortment of 144 tex of polyamide 6 with a structural formula of the fabric (140 tex + 144 tex )×1×2, specific tensile strength of each initial thread 0.82-0.9 cN/dtex, linear density of each initial thread from 1370 dtex to 1520 dtex, linear density of the hybrid warp thread 620±20 tex. The fabric after impregnation is characterized by a breaking load of 450-480 N, an elongation at a load of 45N - no more than 2.5% and a linear shrinkage of 3.0-4.0%.

Description

The utility model relates to the textile industry and relates to a cord fabric used to reinforce the carcass of pneumatic multilayer tires of radial and diagonal designs, in particular, large truck tires and other tires with increased load.

As a reinforcing material for the carcass of multilayer tires, fabrics based on twisted steel or textile threads based on polyamide PA 6 or PA 6.6 are usually used.

Known polyamide cord fabric impregnated with a composition based on latex and heat-treated, the threads of which are made of fiber polyamide 6 in two or more additions with a total linear density (caliber) twisted yarn 5600-6700 dtex. Moreover, the threads of the cord fabric in the impregnated and heat-treated state are characterized by a number of twists of 160-240 revolutions per meter, a minimum breaking load of 450-550 N and an intermediate elongation of 3.0-3.5 ± 0.5% at 45 N (Patent for the invention of the Russian Federation RU2731702 C1, published 09/08/2020).

The disadvantage of the known polyamide fabric is the low performance characteristics (low modularity and high shrinkage), leading to high tire wear due to the use of thick threads with a linear density of up to 6700 dtex from PA 6 in the fabric.

Known hybrid cord fabric, the construction of which is made of a two-strand hybrid yarn of one strand of aramid yarns and one strand of nylon yarns. The hybrid yarns have a nylon content of 45-65 wt.%, a total linear density of 6000 to 9000 dtex and a twist degree of 150 to 400 turns per meter. Moreover, the nylon thread can be made from both PA 6.6 and PA 6. When twisting this complex thread, the supply of aramid is ahead of the nylon thread by up to 3% (Patent for the invention of the Russian Federation No. 2694685, published on 07/16/2019).

The disadvantage of the known hybrid cord fabric is to reduce the adhesive properties of the aramid thread, and the uneven supply of threads to torsion causes the appearance of defects on the hybrid thread, such as loops and twists, which are unacceptable when weaving the fabric.

A hybrid cord fabric is also known, the warp threads of which are formed by twisting polyethylene terephthalate multifilament yarns and nylon yarns with a twist of 100-800 kr/m (RF patent No. 2648653, published on 03/27/2018).

The disadvantage of this hybrid cord is that threads with different physical properties are connected, with different elongation and shrinkage, which makes it difficult to select a rubber compound for tire molding that would provide adhesion when exposed to operating temperatures. It is also possible for the rubberized carcass and breaker fabric to peel off from the tire tread.

Known hybrid cord fabric for the carcass of multilayer tires, selected as the closest analogue, made of threads of polymer polyamide 6 and polymer polyamide 6.6 with a caliber of 2800-3100 dtex each, while the threads of the cord hybrid fabric are characterized by the following parameters in the impregnated and heat-treated state: number of twists 160-240 revolutions per meter; breaking load 450-550 N; intermediate elongation 3.0-3.5±0.5% at 45 N. Cord thread is made of one twisted thread of polyamide 6 fiber and one twisted thread of polyamide 66 fiber. Cord structural formula 280×1×2 or 280×1×3 . Cord fabric threads are taken with the same or similar values for breaking load and elongation. The radial section of the two-strand hybrid cord is characterized by a clear division into two component threads (Fig. 1) (RF patent RU 2729526 C1, published on 08/07/2020).

The disadvantage of the closest analogue is the connection by twisting the threads of two polymers with different properties in the finishing thread. This construction defines the warp thread as a thread with unstable properties in all respects: caliber, breaking load, elongation, twist, shrinkage. This drastically reduces the stability index in all respects and, accordingly, the life of the tire. For example, since the thickness of the double threads is different, this will lead to uneven twist, and, accordingly, in a twisted thread, only one of the threads will carry the load, reducing the breaking load of the fabric due to the effect of the corkscrew thread. In addition, due to the difference in the melting temperature of the strands in the finishing thread, when working in the tire, one thread, melting, will lose breaking load.

The technical problem, the solution of which was provided by the claimed utility model, is the creation of a polyamide hybrid fabric, which is analogous in terms of physical and mechanical properties to cord fabric 45/452A made of polyamide 6.6. In the claimed hybrid cord fabric, a partial replacement of a PA 6.6 polymer thread not produced in the Russian Federation with a PA 6 polymer thread produced in the Russian Federation was made, not only without deterioration in performance, but also with the achievement of improved performance due to the uniform distribution of threads from various polymers in warp cord structure.

The technical result of the proposed utility model is to improve the adhesive properties of the fabric.

The technical result is achieved by the fact that a hybrid cord fabric impregnated with a mixture based on vinylpyridine latex and formed on a base of twisted threads of two polymers of polyamide 6,6 and polyamide 6, and the fabric after impregnation is characterized by a breaking load of 450-480 N, according to the utility model, the fabric is formed elongated warp yarns of 140 tex range of polyamide 6.6 and 144 tex range of polyamide 6 with the structural formula of the fabric (140 tex + 144 tex) × 1 × 2, specific tensile strength of each initial thread 0.82-0.9 cN / dtex, linear density each initial thread from 1370 dtex to 1520 dtex, the linear density of the hybrid warp thread is 620 ± 20 tex, and the fabric after impregnation is characterized by an elongation at a load of 45N - no more than 2.5% and a linear shrinkage of 3.0-4.0%.

At the same time, according to the utility model, the hybrid cord fabric can be produced from warp threads with a total number of not more than 1250 threads.

The technical result is achieved by the fact that the polyamide hybrid cord fabric is made from threads of two different polymers - polyamide 6.6 (PA 6.6) and polyamide 6 (PA 6) with a certain structural formula and physical and mechanical properties of the original threads and fabric after impregnation, arising from the new structure. Physical and mechanical properties of the fabric, such as breaking load in the range of 450-480 N, low linear shrinkage in the range of 3.0-4.0%, specific tensile strength of each original thread 0.82-0.9 cN/dtex, linear density of each initial thread from 1370 dtex to 1520 dtex, the linear density of the hybrid warp thread is 620 ± 20 tex, the elongation of the fabric under a load of 45N is no more than 2.5%, achieved in the production of the fabric, indicate the optimality of the applied loads and the preservation of the polymer structure. The ratio of the amorphous and crystalline parts of the fabric structure remained the same as in the elongated threads, which are raw materials for the hybrid fabric. Preservation of the structure allows us to speak about the achievement of the maximum possible adhesion of the polymer to the impregnating composition and, accordingly, to rubber.

The overstressing of the threads and the achievement of higher rates of breaking load and, accordingly, shrinkage, as well as other indicators, in the production of fabric due to an increase in loads and temperatures, indicates an increase in the crystalline component of the polymer structure, and a clear decrease in adhesive properties, since only amorphous part of the polymer structure provides tissue adhesion.

Both polymers, the threads of which are used in the production of hybrid fabrics, belong to the type of synthetic polymers - polyamides. Polymers have both common properties and differences. Mixing or combining these properties has made it possible to achieve the advantages that a real hybrid fabric has.

Both polymers are characterized by high strength characteristics, heat resistance, high chemical resistance, abrasion resistance, and good antifriction properties. Able to withstand cyclic loads. Retain their characteristics over a wide temperature range.

The differences between the threads of these polymers are in different melting temperatures, elongation stability, elasticity and hygroscopicity, slip and adhesion.

Due to the fact that the chemical process of obtaining polymers is different: PA 6 is the process of hydrolytic polymerization of caprolactam, and PA 6,6 is the polycondensation of adipic acid and hexamitenediamine, the dispersion of the molecular weight of polymer molecules is different. Possessing high dispersion, PA 6 molecules have a greater number of functional groups, which provide high adhesion rates in the system: threads - adhesives - rubber. The connection of the thread with the adhesive depends on the number of functional groups and, accordingly, the number of hydrogen bonds in the polymer. In the connection of the PA 6 thread with the adhesive, there is a significant amount of hydrogen bonds, which exceeds the number of hydrogen bonds when the threads from the PA 6,6 polymer are treated with the adhesive. This state of affairs is due to the fact that the twisted thread in rubber is a screw embedded, for example, in wood. The radial section of the thread of the closest analogue shows (Fig. 1) that the structure of the thread has a different number of hydrogen bonds, because on one turn, one PA 6,6 polymer has a minimum amount of carboxyl (functional) groups of 10.2 mmol/kg, and on the other turn, another PA 6 polymer has a maximum amount of carboxyl groups - 21.5 mmol/kg. The structure of the thread in accordance with the claimed utility model (Fig. 2) suggests that in one turn and in the other turn there is the same number of hydrogen bonds, and it is more than the minimum number of hydrogen bonds in the PA polymer 6.6.

The created hybrid thread with a linear density of 620 ± 20 tex, assembled at the level of assortments of threads serially produced by enterprises 140 tex and 144 tex for the production of polyamide yarns (140 + 144) + (140 + 144) during warping and torsion, combined the entire palette of various characteristics (Fig. 2). In the radial section of the four-strand hybrid cord, the combination and mixing of the two polymers is represented as much as possible.

The claimed utility model can be obtained as follows.

Threads commercially produced by enterprises from a high-viscosity polymer with a specific tensile strength of a thread of 0.82–0.9 cN/dtex and a linear density from 1370 dtex to 1520 dtex were used as feedstock. The connection of the threads was carried out by twisting. At this stage, all the differences between the polymers are combined, which are due to different coefficients of friction of the threads and the difference in the linear densities of the threads up to 15 units. The total linear density was 280±20 tex.

The further process of twisting took place at the same tension of the strands, which ensured the uniformity of the complex yarn. (PA6144tex+PA6.6 140tex)×2=560tex×twist ratio = (620±20) tex. Two threads from PA6,6 out of four in a multifilament yarn allow maintaining the modularity of the multifilament yarn, reaching 400cN/tex, providing low "elongation at 45N", no more than 2.5%, and "linear shrinkage" of the yarn in the range of 3.0-4, 0%, as on a thread consisting of 100% PA 6.6.

From finished twisted threads on a loom, a fabric is formed, based on twisted polyamide hybrid threads in an amount of 60 to 83 pieces. by 10 cm, and in the weft the thread is two-component cotton-polyamide from 8 to 10 pcs. by 10 cm. After that, the cord fabric is heat-treated and impregnated with a mixture based on vinylpyridine latex in one stage on the Benninger STS - 6N-2D-V-80 line, consisting of 6 heating zones and two impregnation baths. The process takes place at temperatures in all 6 zones, the maximum of which is 205°C, this temperature does not allow the destruction of threads from PA 6 and provides an increase in the strength characteristics of the complex thread. The width of the fabric can reach 150 cm, with a thread count of 83 pcs. by 10 cm, i.e. 15×83=1250 threads, which gives a significant increase in production volumes and design possibilities in the production of tires.

The calculation of possibilities is as follows:

maximum load provided by the line - 8.0 t,

maximum thread strength - 480 N,

number of threads from 840pcs. up to 1250pcs,

8-fold safety margin of the thread during drawing, providing break-free impregnation and heat treatment.

480 N×1250 pcs. = 600000 N, /8/9.81= 7500 kg = 7.5 t, the impregnation line is capable of producing fabric up to 150 cm wide.

For example, cord hybrid fabric brand 45/452 N can be produced:

1st option - from two polymers: polyamide 6.6 and polyamide 6. The fabric is formed by threads with a linear density of 1370 dtex with a specific breaking load of 0.82 cN / dtex and 1500 dtex with a specific breaking load of 0.85 cN / dtex, respectively, by means of guiding and then torsion of two filaments. The structural formula of the hybrid thread is (140+144)×1×2. The average linear density of the hybrid warp yarns is 640 tex. The fabric, consisting of hybrid warp threads, is impregnated with a mixture based on vinylpyridine latex and after the impregnation and heat treatment process on the Benninger STS-6N-2D-V-80 line, 1500 mm wide, 60 threads / 10 cm, the total number of threads is 900 pcs. has indicators: "breaking load" - 450N, "elongation at 45N" - 2.5%, and "shrinkage at 177 ° C, 2 min" - 3%;

2nd option - from two polymers: polyamide 6.6 and polyamide 6. The fabric is formed by threads with a linear density of 1450 dtex with a specific breaking load of 0.87 cN / dtex and a linear density of 1480 dtex with a specific breaking load of 0.82 cN / dtex, respectively, by means of guiding and then twisting the two filaments. The structural formula of the hybrid thread is (140+144)×1×2. The average linear density of the hybrid warp yarns is 619 tex. A fabric consisting of hybrid warp threads is impregnated with a mixture based on vinylpyridine latex and after the process of impregnation and heat treatment on the Benninger STS-6N-2D-V-80 line, 1500 mm wide, with a number of 83 threads / 10 cm, the total number of threads is 1250 pcs. has indicators: "breaking load" - 462N, "elongation at 45N" - 2.3%, and "shrinkage at 177 ° C, 2 min" - 3.5%;

3rd option - from two polymers: polyamide 6.6 and polyamide 6. The fabric is formed by threads with a linear density of 1390 dtex with a specific breaking load of 0.84 cN / dtex and a linear density of 1520 dtex with a specific breaking load of 0.9 cN / dtex, respectively, by means of guiding and then torsion of two filaments. The structural formula of the hybrid thread is (140+144)×1×2. The average linear density of the hybrid warp yarns is 632 tex. A fabric consisting of hybrid warp threads is impregnated with a mixture based on vinylpyridine latex and after the process of impregnation and heat treatment on the Benninger STS-6N-2D-V-80 line, 1400 mm wide, 83 threads / 10 cm, the total number of threads is 1160 pcs. has indicators: "breaking load" - 468 N, "elongation at 45 N" - 2.2%, and "shrinkage at 177 ° C, 2 min" - 3.2%;

4th option - from two polymers: polyamide 6.6 and polyamide 6. The fabric is formed by threads with a linear density of 1420 dtex with a specific breaking load of 0.9 cN / dtex and a linear density of 1490 dtex with a specific breaking load of 0.88 cN / dtex, respectively, by means of guiding and then twisting the two filaments. The structural formula of the hybrid thread is (140+144)×1×2. The average linear density of the hybrid warp yarns is 600 tex. A fabric consisting of hybrid warp threads is impregnated with a mixture based on vinylpyridine latex and after the process of impregnation and heat treatment on the Benninger STS-6N-2D-V-80 line, 1500 mm wide, 60 threads / 10 cm, the total number of threads is 840 pcs. has indicators: "breaking load" - 480N, "elongation at 45N" - 2.0%, and "shrinkage at 177 ° C, 2 min" - 4%.

Claims (2)

1. Hybrid cord fabric impregnated with a mixture based on vinylpyridine latex and formed on the basis of threads of twisted two polymers of polyamide 6,6 and polyamide 6, and the fabric after impregnation is characterized by a breaking load of 450-480 N, characterized in that the fabric is formed by elongated warp threads range of 140 tex polyamide 6.6 and range of 144 tex polyamide 6 with the structural formula of the fabric (140 tex + 144 tex) × 1 × 2, the specific tensile strength of each source thread is 0.82-0.9 cN / dtex, the linear density of each source thread from 1370 dtex to 1520 dtex, the linear density of the hybrid warp yarn is 620 ± 20 tex, and the fabric after impregnation is characterized by an elongation at a load of 45N - no more than 2.5% and a linear shrinkage of 3.0-4.0%. 2. Hybrid cord fabric according to claim. 1, characterized in that it is made from warp threads with a total number of not more than 1250 threads.