KR101310142B1 - Aramid multi-filament and method of manufacturing the same - Google Patents

Abstract

The present invention relates to an aramid multifilament and a method for producing the same, before winding the dried aramid multifilament when the aramid multifilament is prepared by spinning, passing the non-coagulated fluid layer, coagulating, washing, drying and winding the aramid spinning solution. Air jammed with an air jammer.

The aramid multifilament according to the present invention has an air entanglement point of 2 to 10 / m in the longitudinal direction thereof, less white powder is generated in the joint twisting process for the production of tire cord, high unwinding, high post-processability .

Aramid, multifilament, twisted yarn, tire cord, air entanglement, interlocking number, post-processability, full winding rate.

Description

Aramid multi-filament and method of manufacturing the same

The present invention relates to aramid multifilament and a method for producing the same.

The present invention relates to an aramid multifilament and a method of manufacturing the same having less white powder generated in a twisted yarn process for producing a tire cord and having a high full-drum rate and excellent post-processability.

Aramid multifilament is disclosed in U.S. Patent Nos. 3,869,429 and 3,869,430, and the like to polymerize an aramid polymer by polymerizing aromatic diamine and aromatic dieside chloride in a polymerization solvent containing N-methyl-2-pyrrolidone. And a process for producing a spinning stock solution by dissolving the polymer in a concentrated sulfuric acid solvent, and spinning the spinning stock solution from a spinneret to pass the spun spinning material through a non-coagulant fluid layer into a coagulating bath to form a filament. And a process of washing and drying the filament.

Aramid multifilament prepared by the conventional manufacturing method as described above is useful as a tire cord yarn with high strength and modulus, but due to lack of focusing, a lot of powder generation occurs in the combined yarn process, one of tire cord manufacturing processes. There is a problem that the post-processability, such as a low full drum rate is lowered.

On the other hand, the tire cord serves to reinforce the tire rubber as one of the components of the tire, and forms a basic skeleton structure in the tire.

The performance required for the cord as a tire reinforcement is fatigue resistance, shear strength, durability, resilience and adhesion to rubber. Therefore, the appropriate code is used according to the performance required for the tire.

Currently commonly used cord materials include rayon, nylon, polyester, steel and aramid.

To manufacture tire cord, give twist (Z-lead) twist to yarn (multifilament) for tire cord manufacture, and then ply it while twisting while giving twist (S-lead) twist to two strands of twisted yarn to manufacture raw cord. Then, it is subjected to a process of immersing, drying and heat-treating the adhesive solution for manufacturing a tire cord.

The raw cord manufacturing process is called a "ply twisted yarn process".

As described above, when the aramid tire cord is manufactured from the conventional aramid multifilament, there is a problem in that the processability is greatly reduced during the twisted yarn weaving process due to the lack of focusing ability of the aramid multifilament.

The present invention provides an aramid multifilament and a method for producing the same, which have less air generation in the twisted yarn process and the like, since air entanglement points are formed in the yarn length direction, and have a high unwinding ratio and excellent post-processability.

Hereinafter, the present invention will be described in detail.

The method for producing aramid multifilament according to the present invention is the aramid multifilament dried as shown in Figure 1 when producing the aramid multifilament by spinning, passing through the non-coagulant fluid layer, coagulation, washing, drying and winding the aramid spinning stock solution Air coil with air duct before winding.

1 is a process schematic diagram of preparing aramid multifilament according to the present invention.

The filament bundle produced by spinning is referred to as 'multifilament', and the raw cord manufactured by the upper and lower edges (or lower and upper edges) of the multifilament is referred to as a 'ply twisted yarn', Finished deep cords treated with an adhesive for the cord are called 'tire cord' or 'code'.

Specifically, in the present invention, a poly (para-phenylene terephthalamide) polymer is prepared by polymerizing an aromatic diamine and an aromatic dieside chloride in a polymerization solvent containing N-methyl-2-pyrrolidone, as shown in FIG. Dissolving the polymer in a concentrated sulfuric acid solvent to form a spinning stock solution, spinning the stock solution from a spinneret, and passing the spun spinning material through a non-coagulating fluid layer into a coagulant bath to form a multifilament, wherein the multifilament After washing with water and drying, air dried with a multi-filament air pulverizer and wound to prepare aramid multifilament.

In this case, the aromatic diamine is P-phenylenediamine and the like, and the aromatic dieside chloride is terephthaloyl chloride and the like.

The polymerization solvent is N-methyl-2-pyrrolidone or the like in which calcium chloride is dissolved.

The intrinsic viscosity of the aramid (fully aromatic polyamide) polymer is 5.0 or more is good for improving the strength and elastic modulus of the filament.

The aramid polymer may be prepared using known polymerization conditions disclosed in US Pat. No. 3,869,429, etc., but the present invention does not specifically limit the polymerization conditions of the aramid polymer.

One example of preparing the polymer is a solution of 1 mole of para-phenylenediamine dissolved in N-methyl-2-pyrrolidone containing about 1 mole of calcium chloride and 1 mole of terephthaloyl chloride in a polymerization reactor. After the addition, it is stirred to prepare a gel polymer, which is ground, washed with water and dried to prepare a fine powder aramid polymer. At this time, the terephthaloyl chloride may be added to the reactor for polymerization divided into two stages.

It is preferable that the concentration of concentrated sulfuric acid used in preparing the spinning stock solution is 97% to 100%, and chlorosulfuric acid, fluorosulfuric acid, and the like may also be used.

At this time, when the concentration of sulfuric acid is less than 97%, the solubility of the polymer is reduced and the liquid crystalline expression of the anisotropic solution becomes difficult. Therefore, it is difficult to manufacture a spinning solution having a constant viscosity, which makes it difficult to control the process during spinning and to provide mechanical properties of the final fiber. Can be degraded.

On the other hand, if the concentration of the concentrated sulfuric acid exceeds 100%, gwari (過離) because in oleum containing SO _3, as well as undesirable phase handled becomes an SO ₃ over takes place is partly dissolved in the polymer spinning solution to the inadequate and In addition, even if the fiber is obtained by spinning, there may be a problem that the internal structure of the fiber is not dense, the appearance is not gloss, and the speed of sulfuric acid diffused into the coagulation solution is lowered, thereby lowering the mechanical properties of the fiber.

On the other hand, the concentration of the polymer in the spinning stock solution is preferably 10 to 25% by weight for the fiber properties.

However, the present invention does not specifically limit the concentration of concentrated sulfuric acid and the concentration of the polymer in the spinning stock solution.

The non-coagulating fluid layer may mainly be an air layer or an inert gas layer.

The length of the non-coagulating fluid layer, that is, the distance between the bottom surface of the spinneret 40 and the surface of the coagulating liquid contained in the coagulating liquid bath 50 is preferably 0.1 to 15 cm to improve the properties of the radioactive or filament.

The coagulant in the coagulant bath 50 may overflow. As the coagulating solution, water, brine or an aqueous sulfuric acid solution having a concentration of 70% or less is used.

Next, the formed filament is washed with water and dried, air-laced with an air entanglement machine, and then wound to prepare an aramid multifilament.

In other words, in the present invention, the multifilament is air entangled with an air entanglement just before winding up in order to give focus to the dried multifilament.

It is preferable to adjust the longitudinal interlacing number of the multifilament to 2-10 pieces / m, and to adjust the air pressure to 1-3 kgf / cm 2 at the time of air interlocking.

When the number of entanglements is less than 2 / m or the air pressure is less than 1 kgf / cm 2, the concentration of multifilament is low, resulting in the generation of white powder in the twisted yarn weaving process, etc. In the case of exceeding or when the air pressure exceeds 3 kgf / cm 2, problems such as lowering of the yarn uniformity may occur.

However, the present invention does not specifically limit the air pressure during air entanglement.

At this time, the spinning winding speed is set to 300 to 1500 m / min.

The aramid multifilament according to the present invention has an air converging point of 2 ~ 10 / m in the longitudinal direction is excellent in focusing, thereby resulting in less white powder generation in the twisted twisted yarn process, etc., high unwinding ratio, excellent post-processability Do.

If the air entanglement point is out of the above range, the focusability is lowered, the post-processability is lowered or the yarn physical properties are lowered.

The strength of the aramid multifilament according to the present invention is 10 ~ 25 g / d, less than 10 g / d, the strength is low, it is difficult to support the vehicle load when applied as a tire cord, the problem of the performance of the tire is impossible, If it exceeds 25 g / d, problems may arise that are not efficient enough to develop tire performance.

In addition, the cut elongation of the aramid multifilament is 2 ~ 6%, if less than 2% due to the low cutting elongation occurs a problem that the fatigue characteristics are insufficient to be applied to the tire cord, when the stability exceeds 6% form stability This scarce problem can occur.

In addition, as the modulus of the aramid multifilament 400 ~ 750 g / d, less than 400 g / d, due to the low modulus, the problem of lack of expression of support capacity for high-speed driving during tire production occurs, exceeding 750 g / d In the case of a high modulus may cause a difficult tire molding.

It is preferable that the total fineness of the aramid tire cord is 800 to 10,000 denier, and the aramid multifilament preferably has a total fineness of 400 to 5,000 denier and is composed of 500 to 1,200 aramid monofilaments. Moreover, it is preferable that the single yarn fineness of the said aramid monofilament is 1-2 denier.

Various physical properties of the aramid multifilament is measured by the following method.

Strength (g / d) and Elongation (%)

According to ASTM D-885 test method, the strength (g) at the time of fracture of the sample yarn was measured using a sample yarn having a length of 25 cm in an Instron Engineering Corp. (Canton, Mass), and then the sample yarn was denier. The strength was calculated by dividing. Elongation at break was calculated as the ratio of the length of the sample yarn to the length of the sample yarn until the sample yarn was broken. The strength and the elongation at break were taken as the average value after five tests. At this time, the tensile speed was 300 mm / min, and the initial load was 1/130 g of fineness.

· Modulus (g / d)

The stress-strain curve of the sample yarn is obtained under the above-described strength measurement conditions, and then calculated from the slope on the stress-strain curve.

· Water

It was measured under a tension of 80 gf by an automatic entanglement measuring device (product name: Rothschild R 2070).

Looking at an example of a method for producing an aramid tire cord with aramid multifilament according to the present invention, the aramid multifilament having the following physical properties by using an Alma twister for a tire cord as shown in Figure 2 counterclockwise Pyeonsangyeon (Z-yeon) twisted and then gave two twisted strands as shown in Figure 3 twisted while giving the twisting direction (yeonyeon Syeon) twisted clockwise to produce a twisted yarn.

2 to 3 are diagrams showing the definition of the upper edge (Z edge) and the lower edge (S edge), respectively.

At this time, the twist number of each of the upper (Z) and the lower (S) is preferably 20 to 60 times / 10 cm.

When the number of twists is less than 20 times / 10cm, the strength is low because the number of twists is high, but the cutting elongation is very low, so that the fatigue characteristics of the cord are bad and the adhesion may be poor as the surface area is lowered.

If the number of twist exceeds 60 times / 10 cm may cause a problem that the strength of the tire cord is reduced due to excessive twist.

Next, the aramid-ply-twisted yarn spliced as described above is immersed in a conventional resorcinol-formaldehyde-latex (RFL) solution so that the pickup ratio is 3 to 12% by weight based on the aramid-ply-twisted yarn. Bath dipping can be used.

Examples of RFL adhesive solution used in the present invention include 2.0% by weight of resorcinol, 3.2% by weight of formalin (37%), 1.1% by weight of sodium hydroxide (10%), styrene / butadiene / vinylpyridine (15/70/15) An RFL adhesive solution comprising 43.9% by weight of rubber (41%), and water is used.

In the present invention, as an example of the adhesive liquid for the adhesive strength of the aramid cord and the rubber can be prepared and used as described above, the above examples are only intended to more clearly understand the present invention, it is intended to limit the scope of the present invention no.

When the pickup rate is less than 3% by weight, the adhesive strength with the rubber is lowered. When the pickup rate is higher than 12% by weight, the penetration rate of the RFL solution (immersion liquid) in the cord is too high, the strength is lowered, and the fatigue characteristics are lowered. Various physical properties such as may be lowered.

Next, the yarn in which the RFL solution is immersed is dried at 105 to 200 ° C. for 10 seconds to 400 seconds, and then heat-treated at 105 to 300 ° C. for 10 seconds to 400 seconds to prepare an aramid tire cord.

When the drying time and the heat treatment time are each lower than the above range, or when the drying temperature and the heat treatment temperature are each below the above range, a low adhesive force may occur.

When the drying time and the heat treatment time each exceed the above ranges, or when the drying temperature and the heat treatment temperature respectively exceed the above ranges, the adhesive force is reduced due to excessive thermal history. The problem of low physical properties may occur.

In the drying process, the moisture present in the aramid multifilament is dried, and in the heat treatment process, the impregnation solution is reacted to impart adhesion to the tire cord.

The aramid multifilament according to the present invention has an air interlacing point is formed in the longitudinal direction thereof has a small percentage of generation in the twisted yarn weaving process, high unwinding ratio, shows an excellent post-processability.

Therefore, the aramid multifilament according to the present invention is useful for producing aramid tire cord and the like.

Hereinafter, preferred embodiments of the present invention will be described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Example  One

An aromatic diamine solution was prepared by maintaining 1,000 kg of N-methyl-2-pyrrolidone at 80 ° C. and dissolving 80 kg of calcium chloride and 48.67 kg of para-phenylenediamine.

The aromatic diamine solution was introduced into the polymerization reactor 20, and at the same time, a molten terephthaloyl chloride of an equimolar amount of para-phenylenediamine was simultaneously introduced into the polymerization reactor 20, followed by stirring them to have an intrinsic viscosity of 6.8. Poly (para-phenyleneterephthalamide) polymer (aramid polymer) was prepared.

Next, the prepared aramid polymer was dissolved in 99% concentrated sulfuric acid to prepare an optically anisotropic radiation stock solution having a polymer content of 18% by weight.

Next, after spinning the spinning stock solution prepared as described above at a spinning winding speed of 1,000 m / min through the spinneret 40 as shown in Figure 1, the radiated spinning material is air layer of 7 mm (non-coagulation) Fluid layer), and then passed through a coagulation bath 50 containing a sulfuric acid aqueous solution (coagulant) having a sulfuric acid concentration of 13% to prepare aramid multifilament.

Next, the multifilament formed as described above was washed with water and dried, and then air entangled with an air pressure of 1.5 kgf / cm 2 in an air entanglement machine and then wound to prepare an aramid multifilament.

The prepared aramid multifilament was staged using a cable & Cord 3 type twister (CC Twister, Allma Co.) 30 times / 10 cm twisted (Z length), and the stranded two strands again 30 times / 10 times Twist the bottom of the twist (S-yeon) by twisting them to prepare a raw material (Raw cord).

Table 1 shows the results of measuring the powder generation and the unwinding rate and the various physical properties of the aramid multifilament in the ply twisted yarn process.

Example  2

Aramid multifilament and cord dough were prepared in the same manner as in Example 1 except that the air pressure was changed to 2.5 kgf / cm 2 during the air entanglement.

Table 1 shows the results of measuring the powder generation and the unwinding rate and the various physical properties of the aramid multifilament in the ply twisted yarn process.

Comparative Example  One

Aramid multifilament and cord dough were prepared in the same manner as in Example 1 except that the dried multifilament was wound without air aeration.

Table 1 shows the results of measuring the powder generation and the unwinding rate and the various physical properties of the aramid multifilament in the ply twisted yarn process.

Results of physical property evaluation division Example 1 Example 2 Comparative Example 1 Aramid
Multifilament Properties Air flow
(Pcs / m) 4 5 0 Average single fineness
(Denier) 1.5 1.5 1.5 Strength (g / d) 22.3 22.2 22.4 Modulus (g / d) 714 713 715 Cutting Elongation (%) 3.2 3.2 3.2 Joint Venture Fairness Percent occurrence
(mg / 100kg) 3.0 2.8 17.8 % Winding rate 98 99 94

Percent generation and the unwinding rate described in Table 1 were evaluated as follows.

· 100 minutes occurrence

After 100 kg of aramid multifilament was twisted and weaved, the weight of the powder attached to various guides and feed rollers of the twisted yarn machine was measured.

· A winding rate

The aramid multifilament is expressed as the ratio of the weight to the full drum of the 100 when the twisted yarn for 100 hours in the 100 weight of the twisted yarn machine.

1 is a process schematic diagram of producing aramid multifilament according to the present invention.

2 to 3 show the definition of the upper and lower edges.

Claims (9)

delete delete delete delete An aramid multifilament, characterized in that the air fusing point of 2 to 10 / m in the longitudinal direction of the multifilament is formed, and composed of 500 to 1,200 aramid monofilaments. The aramid multifilament according to claim 5, wherein the aramid multifilament has a strength of 10 to 25 g / d, an elongation at break of 2 to 6%, and a modulus of 400 to 750 g / d. The aramid multifilament according to claim 5, wherein the total fineness of the aramid multifilament is 400 to 5,000 denier. delete The aramid multifilament according to claim 5, wherein the single yarn fineness of the aramid monofilament is 1-2 denier.

Images