JP7021328B2 - Methods for manufacturing monofilament yarns - Google Patents

Description

The present invention relates to a system and method for the production of yarns, more particularly to the production of strong monofilament yarns.

A typical commercial monofilament production line is a sequential process step / part: cooling of extruded and extruded filaments through a water bath, a first drawing zone, a further (second) drawing zone, heat treatment, and the production of monofilament yarn. Includes winding. Such commercial monofilament production lines typically achieve winding speeds of approximately 150-300 m / min (mpm: also known as meters per minute of yarn) per tire grade monofilament, which are usually used. It flows horizontally and corresponds to a large projection area (about 25 m to 35 m long) allocation per manufacturing system.

US 5 240 772 A discloses a method for producing a polyamide monofilament having an intensity of more than 7.5 gpd (gram weight per denier) and a linear density of more than 1000 denier. A water bath is used to maintain the polymer relative viscosity above 50 (relative to the viscosity of formic acid) and the monofilament core temperature below 55 ° C. A draw point rectifier and steamer were employed to maintain the mechanical properties required of the product, such as the force to resist the tension generated during winding or use. In this process, the first stage stretch roll is heated to 140 ° C to heat the monofilament before entering the second stretch zone; a stretch point localizer and steamer are placed behind the feed roll to accelerate the stretch rate. Placed. In addition, a radiant heater was also used in the heat treatment system.

US 3 963 678 A discloses another process for the production of 10 gpd polyamide monofilaments with linear densities above 1000 denier, where monofilaments have a throughput between 13 kg / h and 20 kg / h (kilograms per hour). It is spun at. However, the number of ends of monofilaments manufactured to achieve this throughput is not disclosed. In high-speed spinning of monofilaments, successfully coping with the continuous production of monofilaments with more than four ends is a great challenge. This challenge requires the design of new processes, appliances and methods. Sequential adoption of stretch point orientation devices and steamers is disclosed in the literature. The monofilament is coated with water at temperatures ranging from 95 ° C to 98 ° C. In addition, the steamers disclosed in this document are loaded with pressures between 80 and 140 psig (5.51 bar to 9.65 bar) at a steam temperature of 180 ° C. The maximum take-up speed is disclosed as 516.7 m / min, but the number of monofilament ends is not yet disclosed.

Achieving high speeds (eg, 500 m / min and above) in monofilament yarn production is a huge challenge, especially when high end counts are required for the yarn. When aiming for a high denier value and a high number of ends in monofilament yarn production, inadequate cooling in the water tank during extrusion, difficulty in capturing the filament with a suction gun, and individual winding of the filament in the godette, etc. I run into some problems. In addition, commercial monofilament lines have low manufacturing capacity due to the low take-up speeds required to prevent damage to the product.

A main object of the present invention is to overcome the above-mentioned drawbacks of the prior art.

Another object of the present invention is to provide a method for obtaining a high denier monofilament yarn having a high number of ends at an accelerated production rate.

A further object of the present invention is to provide a process and method for producing a monofilament yarn with reduced resources and operating costs.

The present invention is the following sequential process unit along the monofilament flow direction: a spinneret and a vertical spinner with a rectifying plate below the spinneret; a water bath for quenching the spun monofilament; for transferring the monofilament from the water bath. Vacuum jet device; steam jet capable of supplying heated steam at a temperature in the range of 300 ° C to 380 ° C and a pressure in the range of 4 bar to 5 bar; stretching unit; and 500 m / We propose a multi-ended monofilament manufacturing device equipped with a monofilament winder that winds the monofilament at a speed exceeding a minute. The present invention further proposes a method for producing a multi-ended monofilament yarn.

The drawings provided with brief explanations are merely intended to provide a better understanding of the invention and are not intended to define the scope of protection or the context in which the scope is interpreted without explanation. ..

FIG. 1 is a table summarizing the process parameters and obtained physical properties of the products in several experimental trials with the apparatus and method of the present invention. FIG. 2 is a schematic diagram showing a process unit of an apparatus corresponding to a process process along a production line according to the method of the present invention. FIG. 3 shows a schematic diagram of a specific example of the apparatus according to the invention, corresponding to aspects of the method according to the invention.

With reference to the drawings outlined above, the present invention proposes an apparatus and method for producing a monofilament yarn.

The methods according to the invention are solid phase polymerization of polyester or polyamide flakes (ie, polyamide 6.6, polyamide 6, polyamide 6.6 / polyamide 6 copolymers or blends thereof), multi-ended monofilament spinning, water quenching, stretching, and monofilament as a product. Includes a sequential process of high-speed winding of yarn.

An overview of the device according to the invention is shown in FIG. 2, a preferred embodiment of the device in which the sequence between process units within the device is highlighted by arrows and also matches the flow direction of the extrude (ie, filament) throughout the device. The flow direction of manufacturing is schematized. Similarly, FIG. 3 illustrates preferred embodiments of the device and manufacturing flow directions.

The device is nearly vertical (when in use, the gravity vector, i.e., downward, i.e., towards the center of gravity of the earth, with a deviation of up to 5 ° (360 ° or more) from the pendulum rope resting in equilibrium. A spinning machine (1) having an extrusion outlet for ejecting the extrusion in substantially parallel or common directions. Therefore, such a spinning machine is defined as a vertical spinning machine. The device is further equipped with a water bath (2) (also referred to as a quenching tank) to quench the fibers and optimize crystallinity upon exiting the spinning machine (1). After the water bath (2), there is a vacuum jet device (3) that transfers the filament in the vertical direction (downward). After the vacuum jet device is a steam jet (4) that supplies heated steam at a temperature in the range of 300 ° C to 380 ° C, preferably in the range of 345 ° C to 355 ° C. Steam pressure is preferably in the range of 4 bar to 5 bar.

Uniform coating of monofilaments with water is very important. This is because otherwise the monofilament will be fragile and will have lower rupture elongation and lower strength.

The equipment and methods according to the invention impart enhanced modules and accelerated speeds throughout the process, which correspond to 3-4 times higher capacity compared to typical commercial spinning lines. The increased capacity results in reduced product costs due to the low operating costs per unit weight of the product (ie, monofilament yarn). The nearly vertical production line means that the equipment requires a minimal projected area that results in reduced resource costs in terms of space use. Cost savings are calculated to be approximately 50% compared to already available commercial monofilament spinning systems. In addition, vertical spinning enables spinning 3-4 times faster than known commercial polyamide monofilament production lines.

In a representative test of the method and apparatus according to the invention, a take-up speed of 1300 m / min was achieved for the production of 12-terminal monofilament yarn. Filaments had linear mass density values ranging from 100 dtex at a filament diameter of 0.1 mm to 3000 dtex at a filament diameter of 0.6 mm; dtex is decitex (ie, in grams per 10,000 meters). It is an abbreviation for (mass of filament). The process parameters and mechanical properties of each product are summarized in Table 1 (Note: Table 1 summarizes the process parameters and obtained physical properties of the products in several trials with the devices and methods of the invention). A 3% stretch load (also known as 3% LASE) and a 4.5 kgf stretch (%) (also known as E 4.5) were considered to indicate the module. The resulting product module was 30-35% higher than the typical commercial monophilamen. For "tire cord" applications, a strength of 7.5 gpd (abbreviation of gram weight per denier) is considered sufficient. Monofilament yarns with higher modular values are advantageous in achieving increased tire stiffness and thereby reduced rotational resistance.

The apparatus according to the invention is used in a representative trial (eg, FIG. 3), comprising a spinneret (11) and a straightening vane (12), under which the extrusion flow (moving vertically from the spinneret) is carried out. Includes a vertical spinning machine (1) that receives and forms monofilament yarn. The flow (indicated by the arrow) continues into the water bath (2). It was preferred to maintain an air gap (13) between the spinning machine (1) and the water bath (2) in the equipment used in the experiment. After the water bath (2), there was a vacuum jet device (3), and a water stripping device (31) was preferentially provided. The filament that has passed through the vacuum jet device (3) is captured by a suction gun (32) (which could also be named a suction jet) and directed to the first drawing zone (33), where the filament is steam jet (3). Following 4), it is attached to a further (second) stretching zone as the main stretching unit (5). In the steam jet (4), steam is applied onto the filament at a pressure of 4.5 bar. The filament is then subjected to a relaxation (51) step and finished with high speed winding of the winder (6). The term "high speed" was used for speeds above 500 m / min, more preferably above 1000 m / min, and even more preferably above 1200 m / min. A take-up speed of 1300 m / min was used in the experimental trial.

In experimental trials, free-fall relative viscosities with respect to formic acid viscosities in the range of 88-100 were employed, more preferably in the free-fall relative viscosities of 93-97. Formic acid relative viscosities (ASTM D 789) of free-fall polymers ranging from 75 to 100, with an intensity of 9.0 gpd and a module of 5.7 GPa (Gigapascal, 109 N / m ² ) (at 2% strain). Achieved at a winding speed of 1300 m / min. At this relative viscosity, the polyamide melts and is extruded from the 12-hole spinneret into a water bath for quenching the spun monofilament. An air gap in the range between 20 cm and 80 cm (the distance that allows the spun monofilament to come into contact with air for the preferred precooling of the newly spun filament) with a water bath and spun hole. Was between. The distance increases the crystallinity of the monofilament material before entering the water bath.

The strength, module and shrinkage behavior of the (mono-) filament is enhanced by further increasing its crystallinity while passing through the water bath. For this purpose, the water bath temperature is preferably maintained in the range of 7 ° C to 20 ° C.

The monofilament is preferentially pulled by the puller roll at the outlet of the water bath, where the puller roll functions by throwing the filament out before it is attached to the vacuum jet (eg, on the floor in front of the outlet of the aquarium). .. In each experimental trial, the linear velocity on the surface of the puller roll in contact with the filament is adjusted to a value in the range of 100 m / min to 300 m / min, depending on the dtex value and winding speed of the monofilament.

The monofilament is preferably dehydrated before contacting the puller roll. The monofilament (which may be dropped onto the floor) may be directed at the vacuum jet by the operator. The vacuum jet device is important for throwing the monofilament down into the drawing unit and transferring the monofilament at high speeds, eg 1300 m / min (multi-end, eg 2-end).

The monofilament transferred to the stretching unit can preferably be captured by the method described in TR 2014/03829. The monofilament is then wrapped around the feed roll. Here, stretching between the puller roll and the feed roll is not desired, therefore the linear velocity on the sides of the feed roll is close to that of the puller roll. In such cases, the ratio between the sides of the feed roll and the linear velocity of the puller roll is preferably in the range between 0.95 and 1.05.

Between the feed roll and the first stage roll, the monofilament was steamed for stretch point localization and increased draw ratio. Steam was applied through the opening at temperatures between 300 ° C and 380 ° C, more preferably between 300 ° C and 340 ° C, and even more preferably within the range of 310 ° to 330 ° C. In the experimental trial, the steam temperature was 320 ° C. Steam pressure was maintained in the range between 4 bar and 5 bar.

The monofilament is then transferred to a (main) drawing point (also named a second-stage roll) where the maximum draw ratio is to monofilament at high speeds (up to 1400 m / min for experimental trials). Gave. Strength is mainly enhanced at this stage. For optimum strength values, the monofilament contact surface of the roll in the main stretching unit is preferably maintained at a temperature in the range of 225 ° C to 250 ° C, more preferably between 235 ° C and 245 ° C. To. In the experimental trial, the surface temperature of the roll in the main stretching unit was maintained at 240 ° C. A total draw ratio of about 5.05x was achieved by the method according to the invention at a take-up rate of 1300 m / min for a 12-ended monofilament.

In the experimental trial, the monofilament was transferred to the relaxation roll as it exited the main stretching unit. The monofilament was then transferred to a brimmed bobbin on a winder with a suction gun (suction jet). The monofilaments were individually rolled and transferred to provide increased productivity. The methods and equipment according to the invention allowed polymer throughput ratios in the range of 16 to 67 kg / h, depending on the linear mass density of the monofilament. In addition, in experimental trials, spinning speeds 3 to 4 times higher were achieved compared to known commercial production lines; regardless of the cross-sectional shape of the product.

The methods and devices according to the invention are particularly suitable for the production of monofilaments with a high number of ends, corresponding to monofilaments above 4-terminal, more preferably monofilaments with 12 or more ends. High-speed, loss-free production of 12 or more terminal monofilaments is highly facilitated by the methods and devices according to the invention.

Claims (6)

The following sequential process:
i) Spin the monofilament in a direction that is substantially parallel or co-directional to the gravity vector from the spun cap with the extrusion outlet hole onto the baffle plate.
ii) The monofilament spun in a water bath maintained at a temperature in the range of 7 ° C to 20 ° C is quenched, where an air gap exists between the spinning machine and the water bath, said air. The gap corresponds to a distance within the range of 20 cm to 80 cm with the exit hole of the spinneret.
iii) Transfer the monofilament from the water bath using a vacuum jet device
iv) Using a steam jet, apply heating steam to the monofilament at a temperature in the range of 300 ° C to 380 ° C and a pressure in the range of 4 bar to 5 bar.
v) Using a stretching unit, stretch the monofilament and
vi) Using a monofilament winder, wind the monofilament at a speed exceeding 500 m / min.
A method for manufacturing a monofilament yarn, including the above. The method of claim 1, wherein the speed exceeds 1000 m / min. The method of claim 2, wherein the speed exceeds 1200 m / min. The following additional sequential process steps:
--Suction of monofilament using a suction gun, and
--First stretching of monofilament in the first stretching zone
The method according to any one of claims 1 to 3, wherein is applied between steps (iii) and (iv). The method according to any one of claims 1 to 4, wherein the multi-ended monofilament is spun from the multi-hole spinning mouthpiece and the multi-ended monofilament is transferred. 5. The method of claim 5, wherein the multi-ended monofilament has 12 or more ends.

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