JPS6385133A - Tire cord fabric and weft yarn therefor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to weft yarns of a tire reinforcing blind fabric made of polyester and a blind fabric using the weft yarns.

<Prior art> In general, tire reinforcing blind fabrics using extensible threads as wefts are stretched as the space between the cords increases when formed into a circular shape in the tire forming process, so the cord spacing in the warp is made uniform. This has the effect of keeping the tires uniform and making the tire mold even.

As such a stretchable yarn, an 8-spun yarn has been proposed in which an undrawn yarn such as polyester is used as a core yarn and the core yarn is covered with a spun. When this 8-spun yarn is used as the weft of a tire cord blind fabric, it has the effect of effectively holding the warp cord in an appropriate position and stabilizing the texture of the fabric during handling and weaving.

However, in order to produce such stretchable 8-spun yarn, a special core spinning device is required, and the production cost is also high.

Furthermore, it has been proposed to use stretchable bulky yarn, which is obtained by applying air jet bulking to undrawn polyamide yarn to form a large number of filament loops on the surface of the yarn, as the weft yarn of tire cord blind fabrics (Japanese Patent Application Laid-Open No. 58-20081). -104238, JP-A-60-110943). here 6
-Nylon and 6.6-nylon are used, but 6.6-nylon is used.
- Nylon has poor heat resistance and cannot be used as the weft of polyester tire cord blind fabrics, which require heat treatment at high temperatures.

In addition, 6,6-nylon has a higher production cost than polyester and cannot be used industrially.

<Objective of the Invention> The present invention aims to provide an inexpensive weft for polyester tire cord blind fabrics that has high elongation, stably contains a large number of loops and slacks, and is easy to handle during weaving. It is something to do.

<Structure of the Invention> The present invention provides a taslan yarn composed of a core yarn and a sheath yarn made of polyester, and having loops and slack, wherein (a) the entanglement coefficient K between the core yarn and the sheath yarn is 0.65 to 0.65; 1.
3 [However, K = (Elongation at break of raw thread for core yarn) / Elongation at break of Kutaslan yarn)] Mountain> Elongation at the primary yield point is 6% or lesstel Pulling resistance value A of the core yarn at the primary yield point is 0.57 g
/de or more [However, A = (Load at primary yield point - 18,2
g) / (Fineness de of core yarn)] (d) Breaking elongation is 100% or more (e) Dry heat shrinkage rate is 3% or less Weft for tire cord blind fabrics .

The polyester referred to in the present invention is a polyester whose main constituent unit is ethylene terephthalate, and may be a polyester in which a part of the terephthalic acid component is replaced with another dicarboxylic acid component, or a polyester in which a part of the ethylene glycol component is replaced with another dicarboxylic acid component. It may also be polyester in which the diol component is replaced.

Its degree of polymerization is usually in the range of 100-110.

The Taslan yarn, which is the weft of the present invention, must have an entanglement coefficient K of the core yarn and sheath yarn constituting it in a range of 0.65 to 1.3. However, K = (breaking elongation of raw yarn for core yarn) /
(Elongation at break of Taslan yarn) When this K does not reach 0.65, the winding is low and the loops are large, making it difficult to handle in the subsequent process and making it impossible to hold the warp threads of the woven blind in an appropriate position. When K is greater than 1.3, it is difficult to obtain the necessary elongation at break.

The elongation of Taslan yarn at the primary yield point is 6% or less. When this elongation is greater than 6%, the weavability and handling properties of the blind will deteriorate.

Further, it is necessary that the pull-out resistance value A of the core yarn at the primary yield point of the Taslan yarn is 0.57 g/de or more. However, A = (Load at primary yield point - 18,2SJ)/
(Fineness de of the core yarn). When A does not reach 0.57, the weaving properties and handling properties of the blind are poor.

Furthermore, the Taslan yarn must have an elongation at break of 100% or more and a dry heat shrinkage rate of 3% or less when heat treated in a free state at 150° C. for 30 minutes. If the elongation at break and the dry heat shrinkage rate are out of this range, the workability during tire production using blinds and the uniformity of the resulting tire will deteriorate.

The fineness ratio of the core yarn to the sheath yarn in the weft of the present invention can vary over a wide range, but is preferably in the range of 1:1 to 6:1. Moreover, the total fineness of this weft is preferably in the range of 130 to 270 de.

The polyester yarn used for manufacturing the above-mentioned Taslan yarn must have a breaking elongation of 120% or more, for example, 2500 to 60%.
It can be obtained by high-speed spinning at a spinning speed of 0.007 FL/min, or by a conventional method, such as a method of drawing an undrawn yarn spun at a spinning speed of 800 to 1500 m/min at a low ratio.

The yarn obtained by the above method has a dry heat shrinkage rate (150℃ x 30
) of the measurement conditions is large and dimensional stability is poor. In order to improve this and further increase the elongation at break, the core yarn is heat treated by passing it through normal pressure boiling water or hot air at 120°C or higher under overfeed, and at the same time the dry heat shrinkage rate is reduced to 10% or less. Increase elongation at break by at least 10%. An appropriate overfeed rate at this time is 8 to 40%.

If it exceeds 40%, the Young's modulus decreases, making it difficult to handle in subsequent steps, which is not preferable. Overfeed rate is 8
% or the dry heat temperature is less than 120° C., the predetermined dry heat shrinkage rate cannot be obtained and the elongation at break does not increase by 10% or more.

The yarn that has gone through the above steps is used as a core yarn, and a polyester yarn that is not heat treated and has a breaking elongation of 120% or more is used as a sheath yarn and subjected to ordinary air jet bulking processing. At this time, if the degree of entanglement becomes too large, a high elongation and bulky textured yarn having a breaking elongation of 100% or more cannot be obtained. Therefore, the overfeed rate of the core yarn should be 5% or less, and the entanglement coefficient of the core yarn and sheath yarn should be 0.65 to 1.
Set the conditions so that it becomes 3. However, the entanglement coefficient = the breaking elongation of the core yarn/the breaking elongation of the Taslan yarn. In addition, the overfeed rate of the sheath yarn is required to be at least 50% in order to stabilize the weave of the fabric, and the difference in the overfeed rate between the sheath yarn and the core yarn is determined in order to make the elongation at break more than 100%, and to stabilize the weave of the fabric. In order to stabilize the weave, it is preferable to make it 48% or more.

The yarn that has undergone the above process has large loops and is difficult to handle in subsequent processes, so it is subjected to dry heat treatment. At this time, the sheath yarn, which has a high dry heat shrinkage rate, mainly shrinks and the loop becomes smaller, which greatly improves the ease of handling in the subsequent process.

In this case, the appropriate overfeed rate is -10 to 30%, and the dry heat treatment temperature is 100 to 230°C. When the overfeed rate is less than 120%, the elongation at break decreases, and when the treatment temperature is less than 100℃, the effect of making the loop smaller is small, and when the overfeed rate is more than 30% or the treatment temperature is less than 230℃. When it is high, the entanglement between filaments becomes too good, making it difficult for the elongation at break of the high elongation bulky yarn to exceed 100%.

The settings of these conditions are appropriately adjusted depending on the strength and elongation of the yarn used, the primary yield point, the number of filaments, the single yarn de, and the configuration of its core effect. In addition, if the dry heat shrinkage rate of the wound yarn is still high and the pull-out resistance value A is low, [However, A - (Load at primary yield point - 18.2 g) / core yarn fineness 3 wound yarn There is also a method of heat-treating the film as it is or after rolling it. In this process, the loops and slack of the high elongation, bulky yarn are bound by the winding layer, so the shrinkage of the loops and slack yarn is relatively small, and the dry heat shrinkage rate of the system as a whole is low, and the drawing resistance value A You can obtain yarn with high Heat treatment temperature is 80-140℃ for wet heat and 110-230℃ for dry heat.
or appropriate. Moist heat lower than 80°C or dry heat lower than 110°C is less effective, and wet heat higher than 140°C or dry heat higher than 230″C reduces elongation at break and is not appropriate.

If the breaking elongation of the weft yarn of the present invention is less than 100%, the desired uniform tire cannot be obtained due to insufficient elongation of the weft yarn during tire formation. In addition, if the dry heat shrinkage rate of the weft becomes too large, the dimensional stability of the fabric against heat will deteriorate, making it difficult to obtain a tire as designed. Therefore, the dry heat shrinkage rate should be 3% or less. It is.

The high elongation bulky textured yarn of the present invention obtained through the above steps is arranged as a weft at a density of 2/5 cm or more, while the warp is 1000 de x 2 polyester tire cords,
1500 de x 2 or 1000 de x 3 to 4
To make a tire cord blind fabric arranged at a density of 0 cords and 15 cm or more.

<Example> The present invention will be explained in detail below with reference to Examples.

The following examples used the apparatus shown in FIG.

FIG. 1 shows an example of an apparatus suitable for manufacturing the weft yarn of the present invention, in which 1 is a core yarn package, 2 is a sheath yarn package, 3 is a core yarn supply 0-ra, 4 is a heater, 5
6 is a supply roller for the core yarn after heat treatment, 6 is a supply roller for sheath yarn, 7 is an air jet, 8 is a take-up O-ra (also serves as a supply roller to the heater at the same time), 9 is a heater, and 10 is a take-off roller.

11 is a winding machine.

Example 1 Core yarn was melt-spun at a winding speed of 40,007 FL/min, elongation at break 122%, strength at break 332 gr, 11 degrees 1
65 de.

A 24-filament undrawn polyethylene terephthalate yarn was heat-treated by passing it through a heater having a length of 1.007 FL and a temperature of 163° C. at a feeding rate of 1497 FL/min and an overfeed rate of 20%. The elongation at break after heat treatment was 164%, an increase of 24%.

This heat-treated yarn is used as a core yarn, and the sheath yarn is wound at a winding speed of 3800.
Melt-spun at m/min, elongation at break 118%, strength at break 8
Air jet bulking was performed using undrawn polyethylene terephthalate yarn of 8Qr, fineness of 45de, and 12 filaments. Processing conditions are core yarn overfeed rate 1
%, sheath yarn overfeed rate 100%.

Fluid air pressure 4. OKI/cIiG, feeding speed is core thread 12
4.2 m/min, sheath yarn 246 m/min, feeding speed after processing 123 m/min, and the core and sheath yarns were soaked with water before the air jet nozzle to weaken entanglement between the core and sheath yarns. I didn't. As a method of weakening entanglement, the fluid air pressure may be lowered, or the processing yarn speed may be increased.

The above air jet bulky yarn was processed at a yarn speed of 123 m/min.
After heat treatment by passing through a heater at a temperature of 160° C. with an overfeed rate of 0%, the yarn was wound at a yarn speed of 123 TIL/min.

The elongation at break of the obtained bulky textured yarn was 151%, and the drawing resistance value A [A-(load at primary yield point -18.2 Or)/fineness of elongation] was 0.65 g/de.

Furthermore, the above yarn was set with moist heat at 105° C. for 30 minutes.

The obtained yarn has a fineness of 300 de and a core:sheath fineness ratio of 2.22.
:1, the elongation at break is 149% and the pull-out resistance value A is 0,879/
The dry heat shrinkage rate was 2%, the 2gM entanglement coefficient was -0.82, and the elongation at primary yield point was 3.8%. This thread is used as the weft thread, and the warp thread is polyethylene terephthalate tire cord 1000.
A radial tire carcass fabric with a density of 49.4 15α fibers was woven using two deX fibers.

A resorcin formaldehyde solution having a composition that allows gum adhesion to polyester was applied to this fabric, dried at 150°C for 4 minutes, and then heat-treated at 240°C for 2 minutes.

The strength of the weft after heat treatment is 4219. Breaking elongation is 117%
Met.

165-8R using this blind fabric for tire cord.
-A radial tire of B size was molded.

When a green tire is molded, the weft yarns follow the increasing spacing of the warp yarns during the process of expanding the molded carcass, and the warp yarns are arranged uniformly. In this case, the tire uniformity level (radial force variation) level was 8.5 kg, and no unevenness was observed in the sidewall portion, and extremely good results were obtained.

Example 2 Instead of the yarn used as the core yarn in Example 1, a yarn with a breaking elongation of 122, which was melt-spun at a winding speed of 3900 m/min, was used.
0%, breaking strength 252Qr, 11 degrees 125de, 3
A 6-filament polyethylene terephthalate undrawn yarn was used, and the yarn was processed under the same conditions as in Example 1 except for the other steps.

The obtained yarn has a fineness of 260 de and a core:sheath fineness ratio of 1.68.
:1, the elongation at break is 156% and the pull-out resistance value A is 0.729/
The dry heat shrinkage rate was 2.1%, and the 1-circuit coefficient was -0.78.

The elongation at the primary yield point was 5.0%. Furthermore, the above yarn was used instead of the yarn used as the weft in Example 1,
A radial tire fabric was manufactured under the same conditions as in Example 1 in other steps. The elongation at break of the fabric after heat treatment at 240°C is 1
It was 15%.

Comparative Example 1 In the yarn processing of Example 1, the core yarn was soaked with water before the taslan processing, and the other conditions were the same.

The obtained yarn had a fineness of 303 de and a breaking elongation of 91%.
A fabric for a carcass of a radial tire was woven in the same process as in Example 1 except that this processed yarn was used as a weft.

Since this weft yarn had insufficient elongation at break, a uniform tire could not be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an apparatus suitable for manufacturing the weft yarn of the present invention. In the figure, 1 is a package for the core yarn, 2 is a package for the sheath yarn, and 3 is a package for the sheath yarn.
4 is a core yarn supply roller, 4 is a heater, 5 is a core yarn supply roller after heat treatment, 6 is a sheath yarn supply roller, 7 is an air jet, 8 is a take-up roller (also serves as a supply roller to the heater at the same time) , 9 is a heater, 10 is a take-up O-ra, 1
1 is a winding machine. Figure 1

Claims (5)

[Claims] (1) A taslan yarn consisting of a core yarn and a sheath yarn made of polyester and having loops and slack, as shown below (
A weft yarn for a tire cord blind fabric that satisfies the conditions of a) to (e). (a) The entanglement coefficient K between the core yarn and sheath yarn is 0.65 to 1.3 [
However, K = (Elongation at break of raw thread for core yarn) / (Elongation at break)] (b) Elongation at the primary yield point is 6% or less (c) Pulling resistance value A of the core yarn at the primary yield point 0.5
7 g/de or more [However, A = (Load at primary yield point - 18
．． 2g)/(Fineness of core yarn de)] (d) Breaking elongation is 10
0% or more (e) Dry heat shrinkage rate is 3% or less (2) The weft yarn for tire cord blind fabrics according to claim 1, wherein the fineness ratio of the core yarn to the sheath yarn is 1:1 to 6:1. (3) Composed of a core yarn and sheath yarn made of polyester,
A taslan yarn having loops and slack, and the following (a)
)~(e) 2 yarns/5c as weft yarns that satisfy the conditions
A tire cord blind fabric characterized in that polyester tire cords are arranged at a density of m or more, and polyester tire cords are arranged as warp threads at a density of 40 cords/5 cm or more. (a) The entanglement coefficient K between the core yarn and sheath yarn is 0.65 to 1.3 [
However, K = (Elongation at break of raw thread for core yarn) / (Elongation at break)] (b) Elongation at the primary yield point is 6% or less (c) Pulling resistance value A of the core yarn at the primary yield point 0.5
7 g/de or more [However, A = (Load at primary yield point - 18
．． 2g)/(Fineness of core yarn de)] (d) Breaking elongation is 10
0% or more (e) Dry heat shrinkage rate is 3% or less (4) The fineness ratio of the core yarn and sheath yarn in the weft is 1:1 to 6
The tire cord blind fabric according to claim 3, which is: 1. (5) The tire cord blind fabric according to claim 3, wherein the warp yarns are 1000 de x 2 warps, 1500 de x 2 warps, or 1000 de x 3 warps twisted together.