KR840000432B1 - A method of producing melt-spun crystalline filaments which are stretched to orientate the molecules - Google Patents

Abstract

Crystalline filaments stretched for molecule orientation, is prepd. from a synthetic polymer, such as polyethylene terephthalate, polyamide, or polyolefin resin. Filament is yarned in a melting state from the nozzle; cooled to a temp. below its setting condition; streched on a heating surface at more than 3500 m/min; and heated and streched on a heating surface which is 20-300 mm length. This is heated under 450-650oC, and is located 1500-6500 mm away from the yarning nozzle.

Description

Method for producing crystalline filament

1 shows the progress of the method according to the invention.

2 is an enlarged view showing a slope path in a heating surface area.

3 shows a possible method of making a mixed filament yarn.

The present invention relates to a method for producing melt-spun crystalline filaments.

More specifically, the present invention prepares a crystalline filament capable of orientating molecules by drawing from a synthetic polymer, cooling the spun filament below a set temperature, and then at least 3,500 m / min, preferably 4,100 to 6,000 m. A method for producing a crystalline filament characterized in that it is drawn on a heating surface at a rate of / min, and then heated and stretched in a heating surface area at a temperature above a set temperature, preferably at a temperature of 150 ° C or higher.

A method of this type is known from JP 2117659. In the method of this patent, the heating surface is a hot plate, and the length of the hot plate should be selected so as to provide a temperature sufficient to achieve the purpose of temple orientation and crystallization. In Example 5 of German Unexamined Patent Publication No. 2117659, the length of the hot plate is 1,000 m at a temperature of 169 ° C. In the above embodiment, the filament discharged from the spinneret is cooled below the set temperature in the hot plate upstream and then subjected to the tensile stress in the thread by friction with the surrounding gaseous medium (this should be equal to the tensile stress required under certain conditions). It is formed at the same time and heated above the set temperature on the hot plate. Stretching of the filament, which affects molecular orientation and increased crystallization, takes place under the action of heat and tension. At a feed rate of 4,000 m / min or more and a dead temperature of 220 ° C. or more, a draw ratio of 2: 1 or more is observed by a known method using polyethylene terephthalate filament.

The known method has a number of disadvantages. In this method, since the filament can be treated with an anti-friction emulsion only after the filament has passed through the hot plate, the relatively long hot plate creates a significant mechanical force on the filament, thereby saving and heat due to fiber wear on the hot plate. Embrittlement will increase further. This degrades the cleanliness of the thread and also causes frequent trimming. It is difficult to increase the feed rate by about 3,500 m / min, and at a feed rate above about 4,000 m / min, too many radiation barriers make economic production impossible.

It is an object of the present invention to provide a method of the type mentioned above which can easily carry out work even at high feed rates of 6,000 m / min or more. Moreover, the simplification in the device should be able to reduce the investment and energy costs, in particular the heat stress on the workers in the workplace.

The present invention seeks to provide a method for producing crystalline filaments that can be oriented from a synthetic polymer to orient molecules, wherein the filaments are melt-blasted from the spinneret and cooled below a set temperature and then at a rate of 3500 m / min or more. Stretching on a heating surface, followed by heating in the heating surface area to a temperature above the set temperature, wherein the heating surface is 20 to 300 mm in length and heated to a temperature of 450 to 650 ° C. and is also 1,500 to 6,500 mm from the spinneret. It is characterized in that placed in the distance.

The length of the heating surface is preferably 200 mm or less, and its temperature is preferably 500 to 600 占 폚.

The mechanical stress caused by friction in the filaments running on these surfaces can be reduced to a reasonable minimum by significantly reducing the conventional 1,000 mm or longer heating surface length at feed rates of 3,500 m / min or more. In a known method, it is preferable to use a hot plate as a heating surface originally. A length of 20 to 300 mm, preferably 200 mm or less, proven as a threshold, indicates the contact length between the filament and the hot plate. However, the hotplate may provide a heating pin or other contact heating surface instead of the signal hotplate if the total contact length is shorter than the critical limit described above. The surface of the heating surface used can be further enhanced to suit the thread by special treatment. As such a heating surface, an electrochemically chromium plated surface, a plasma coated surface, or a surface coated with nickel diamond is preferable. Also, a hot plate made of, for example, a ceramic material may be used. _{R t (peak-to-valley} heights R t) of the apex height of the goal is a 4 to 15μm is preferred.

Since the heating surface rises rapidly from the maximum temperature of about 220 ° C to 450 to 650 ° C, in other words, the used heating member is in a thin red state, and thus, the contact surface is heated in spite of a short contact time. Not only shorter filaments but also by burning the fiber impurities deposited on the heating surface, the heating surface is always clean and spun It is also surprising that it does not produce frictional forces caused by known forms of impurities that are detrimental to it. The predetermined temperature range is a threshold. Thermal damage of the filament cannot be ruled out if the temperature rises higher. On the other hand, since lower temperatures do not result in inevitable combustion of impurities, the risk of mechanical damage of the filaments on the heating surface increases again because the self-cleaning effect underlying the present invention is no longer guaranteed.

The spacing between the spinneret and the heating surface should be referred to as the third important effector. This spacing range should be 1,500 to 6,500 mm, preferably 4,000 to 01000 mm. The increase in thread tension in the upstream of the heating surface is largely influenced by this spacing, mainly due to air friction on the drop shaft. The thread tension on the heating surface is substantially affected by the length of the heat pipe and also by the coefficient of friction between the thread and the heating surface.

Examining the above conditions, the filaments are drawn at least 2: 1 in the heating surface area. The term "stretching" is interpreted to mean conventional stretching in connection with molecular orientation and crystallization. In general, this stretching does not occur at any particular point in the heating surface area but occurs within the stretching section. As a result of stretching, the strength of the filament increases while its elongation and shrinkage decrease. Representative data on the properties of polyethylene terephthalate yarn are as follows. Cutting strength 35 ~ 50CN / tex, cutting elongation about 18 ~ 35%, hot air shrinkage (190 ℃) 6 ~ 10% and boiling measurement about 3 ~ 10%.

However, the process according to the invention can be carried out not only with polyester but also with other conventional synthetic polymers which can be fired in filament form from the molten state (eg polyamides or polyolefins). The polymer can be modified by adding a modifier such as titanium dioxide, carbon or an antistatic agent. The filaments are wound in combination in the form of dreads or processed into fiber form by conventional methods. This method is particularly suitable for producing smooth yarns. However, spuntextured yarns or other rough yarns can be prepared by the methods described in more detail below.

It has already been emphasized that the spacing between the heating surface and the spinneret must be large enough to allow the freshly spun filament to cool below the set temperature. The filament reaches a set temperature if its diameter no longer changes. For many polymers, the setting temperature should be considered in view of the high cooling rate of the individual filaments occurring directly under the spinneret. This equation can be deduced from a publication (for example, publication 2,117,659, previously described).

The term " take off speed " in the present specification means the speed when the filament passes through the stretching section described above. This speed may be the same as the winding speed but need not be the same.

In order to obtain a particularly uniform filament yarn, it is preferable to press the filaments against the heating surface with a threaded guide member disposed downstream of the heating surface. This crimping process should be carried out mechanically and carefully using lightly rotating crimping arranged immediately downstream of the heating surface. The filaments are preferably deflected at an angle of 2.5 to 10 degrees, in particular 3 to 5 degrees, as they pass through the heating surface. This angle is an acute angle intersecting with each other between the extension of the filament which transitions from the spinneret to the heating surface and the extension of the filament which is transferred from the heating surface to the first dred guide member (roll, oil ring cylinder, etc.) downstream from the heating surface. to be.

As soon as the filament is fixed, but before running over the heating surface, it is also possible to treat the filament with an oil having a boiling point located in the preferred drawing temperature region. This prevents thermal damage of the filament on the heating surface, but the condition of the workplace is quite complicated by the evaporating oil which is constantly evaporating. Therefore, it is desirable to wet the filaments with an emulsion only after the filaments have passed the heating surface.

The threaded guide member which helps the pressing of the filament on the heating surface can preferably wet the filament and the emulsion simultaneously.

Embodiments of the method according to the invention described so far lead to a smooth yarn of the form which can be used, for example, in a weaving or knitting machine for making curtains. The contact condition between the filament and the heating surface is such that within the crystal structure the bicomponent structure is created in the transverse cross section of the filament and induces different shrinkage on the side of the filament so that the individual filaments are wound on the transverse cross section of each filament during the appropriate post-processing. It is preferable to select in such a way as to cause a slope. This bicomponent structure is formed when the upper limit of the above-mentioned deflection angle, for example, in the range of about 7 to 10 degrees is selected. Apart from this type of textured processing, there is also the possibility of incorporating other textured processing methods, such as blade crimping or false twist texturing, into the spun drawing method according to the invention.

Furthermore, it is also possible to produce beneficial blended yarns by the method according to the invention from filaments that shrink somewhat differently. In particular, this is done by guiding the filament portions in contact with the heating surface weaker than the remaining portions of the filaments. The term "weaker contact" refers to the filament portions being guided on a shorter heating surface than other filament portions, or It may mean that the temperature of the passing heating surface is lower, or the pressure applied is smaller. In extreme cases, the threaded portion may be guided without contact with the heated surface to form spun-drawn blended yarns and high-speed spun filaments with clearly different shrinkage and elongation.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to attached drawing.

In FIG. 1, the filament 2 discharged from the spinning nozzle 1 is first cooled to a temperature below the set temperature. After passing through the dropping shaft 3, the filament 2 is guided on a heating surface 4, for example a plasma coating hot plate (length 40 mm) at a temperature of 550 ° C. An overrun roller 5 disposed downstream of the hot plate regulates the pressure of the filament 2 against the heating surface 4 and also controls the deflection angle α shown in FIG. The stretched filaments are for example wetted with an oil in the oil ring cylinder 6 and then supplied to the winding device 7. The deflection cylinders 8, 9 are provided to obtain a long shot-effect triangle at a relatively small overall height and to reduce the tension to a suitable winding tension.

3 shows a heating apparatus in which filaments 12 and 13 pass through two heating surfaces 10, 11. The filament 12 passes over both heating surfaces 10, 11, while the filament 13 only contacts the lower heating surface 11. The filament bundles 12 and 13 are drawn under different contact conditions, and then completely joined and mixed by an air jet to be wound up as mixed filament yarns.

The present invention will be described in more detail with reference to the following Examples.

Example 1

Polyethylene terephthalate chips mated with titanium dioxide were melted and spun from 24 spinneret dieplaters. The melt injection amount is about 29.5 g / min. Twenty-four filaments are transferred on a plasma coated hotplate (length 75 mm) heated to 550 ° C. at a rate of 4028 m / min. The vertex and valley depth R _t of the plasma coating is about 11 μm. The spacing between the spinneret and the hot plate is about 5,000 mm.

The dead temperature is 26 ° C in the hot plate upstream and 158 ° C in the hot plate downstream. The yarn fineness is 240 dtex upstream of the hotplate and 78.5 dtex downstream of the hotplate. The yarn tension is 16g upstream of the hotplate and 26g downstream of the hotplate.

The properties of the manufactured yarn are as follows.

Such yarns are manufactured using the apparatus of the type shown in FIG.

Example 2

The polymer as in Example 1 is spun from an injection dose of 40.6 g / min from the 24 spin nozzle die plates. The plasma coating hot plate has a length of 75 mm, a depth R _t between the vertex and the valley of 5 m, and a temperature of 550 ° C. The hot plates are spaced 5,000 mm from the spinneret.

The dead temperature is about 30 ° C in the hot plate upstream and 160 ° C in the hot plate downstream. The yarn fineness is 209.5 dtex upstream of the hotplate and 77.5 dtex downstream of the hotplate. The yarn tension is 28 g upstream of the hotplate and 38 g downstream of the hotplate.

Such yarns are manufactured using the apparatus shown in FIG. 1, in which an air jet is placed upstream of the take-up device to improve the thread end.

The properties of the manufactured yarn are as follows.

Example 3

The polycaprolactam chip, which was extinguished with 0.4% titanium dioxide, was spun from 24 spinning nozzle die plates. The injection volume of the application is 29.1 g / min. The filaments are transferred by the method shown in FIG. 1 at a rate of 3,985 m / min on an electrochemically chromium plated hot plate (R _t = 8 μm) of length 75 mm. The temperature of the hot plate is 500 ° C. The spacing between the spinneret and the hot plate is 5,00 mm.

The characteristics of the filament yarn produced are as follows.

Claims (1)

In the method for producing a crystalline filament capable of stretching molecules from a synthetic polymer to orient the molecules, the filaments are melt spun from a spinning nozzle to cool below a set temperature, stretched on a heating surface at a speed of 3,500 m / min or more, and then set Characterized in that it is stretched in the heating surface area above the temperature, and the heating surface in the filter is heated to a temperature of 450 to 650 ° C with a length of 20 to 300 mm and is placed at a distance of 1,500 to 6,500 mm from the spinneret. Method of Making Filament.

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