CS243994B1 - Process for preparing polypropylene monofilaments - Google Patents

Abstract

The invention relates to a method of preparing polypropylene monofilaments suitable for rope production. The spun polypropylene monofilament is drawn to a draw ratio of 1:7 to 1:10 and then air-fixed at 140 to 170 °C, with a shrinkage of 0.98 to 0.90, and then immediately cooled with water containing a surfactant to a temperature of 10 to 40 °C.

Description

Author of the invention KUBÍČEK JAROSLAV ing., TÁBOR;

FISHERIES FRANTIŠEK, SEZIM0V0 ÚSTÍ (54)

Process for preparing polypropylene monofilaments

The invention relates to a process for preparing polypropylene monofilaments suitable for the production of ropes. The fiberized polypropylene monofilament is drawn to a draw ratio of 1: 7 to 1: 10 and then fixed with air at 140 to 170 ° C, with a shrinkage of 0.98 to 0.90 and then immediately cooled with water containing surfactant to 10 ° C. to 40 ° C.

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The present invention relates to the preparation of polypropylene monofilaments having a diameter of 0.1 to 0.5 mm suitable for making stranded ropes.

Braided ropes are made of metal, vegetable or synthetic fibers. Metal fibers are characterized by a high specific gravity, while fibers of non-noble materials are easily subject to corrosion. Natural fibers are readily biodegradable, wetted, thereby altering their physico-mechanical properties, which adversely affects the properties of the resulting rope. Fibers or monofilaments of synthetic materials have a number of advantages for these applications, such as high strength and low density. If polyolefin or polyester fibers or monofilaments are used, these are non-wetting, do not hydrolyze in water and are not attacked by microorganisms. With regard to monofilaments intended for the production of ropes, they must comply with certain requirements for their strength, tensile strength, uniformity of diameter, shrinkage at higher temperatures and resistance to shock loads. The properties of the starting monofilaments largely affect the utility properties of the rope. On the other hand, these characteristics must be

meet the requirements caused by own technology of rope braiding.

• Monofilament strength values indicate their resistance to slow and uniform force. In reality, however, we often encounter shock loads, that is, rapid changes in the applied force. An important characteristic of monofilaments in this respect is the deformation work, that is, the work required to break the monofilaments. This property of the monofilaments can be influenced by the method of its preparation, in particular by the stretching ratio used and the thermal effect on the extruded monofilaments, which affects its supramolecular structure. The supermolecular structure of the monofilaments, especially the orientation and content of the crystalline phase / also influence other properties of the monofilaments such as its abrasion resistance, resistance to permanent deformation due to long-term loading, etc. · 243 994

BACKGROUND OF THE INVENTION The present invention relates to the preparation of polypropylene monofilaments having a diameter of 0.1 to 0.5 mm suitable for the production of ropes. The fiberized monofilaments are drawn to a total draw ratio of 1 > 7 and 1: 10. 20 m / min at 130 to 170 ° C for 0.5 to 4 seconds / with monofilaments able to shrink by 2 to 10% relative to their original length and then cooled with water containing surfactants to 15 to 40 ° C ·

The preparation of the polypropylene monofilaments according to the invention is simple and most production lines consisting of a melt extruder, a drawing device and a winding machine can be used. Monofilament breakages and production failures and / or excessive waste generation are avoided during stretching and fixation. Monofilaments are smooth on the surface without defects. The monofilaments after winding on the reels are no longer lethal and easily unwind from the reels. Preferably, a plurality of monofilaments, typically 4 to 8, are wound on the thread. These then form the base strand of the rope, thereby avoiding initial pooling of the monofilaments into the base strand. The uniformity of the monofilament diameter is satisfactory.

The starting material for the preparation of the monofilaments according to the invention is isotactic polypropylene or a copolymer thereof with a small amount (up to 10%) of higher olefins, which does not contain gel-like particles, i.e. foil or fiber type. the rope's resistance to aging. A suitable flow index of polypropylene is 1.5-6 g / 10 minutes. The polypropylene granulate is spun on conventional extruders. In order to increase the uniformity of the monofilament diameter / both along its length and between the individual monofilaments produced at the time of production, the extruder is equipped with a gear metering pump. The fiberized monofilaments, after leaving the spinneret, are cooled in a water bath to a temperature of 20 to 50 ° C. The drawing of the monofilaments occurs in a known manner between the galets (i.e. due to their different velocities). between which are drawn. The monofilaments are heated by hot water or hot air during drawing. The drawing is preferably carried out in two stages.

In the preparation of the monofilaments according to the invention, the elongated mono243 994 films are treated with hot air which is immediately and / or partially shrinked in a controlled manner. The thermal fixation of the monofilaments is usually carried out in a hot-air heating zone & located between two extraction units with 3 to 7 galets. By regulating the speed of the galets of the exhaust units it is possible to achieve the required level out of shrinkage of the monofilaments during their heat fixation. After the monofilaments leave the fusing zone and are withdrawn by the withdrawal unit, they are rapidly cooled by the water-containing surfactant. This cooling is usually accomplished by passing the monofilament over the surface of a rotating roller which is wetted by an aqueous surfactant solution or by passing through a water bath. Particularly suitable for this purpose are textile formulations containing emulsifying and wetting agents. The final stage of the preparation of monofilaments is their winding on reels. Due to the rapid cooling of the monofilaments after their fixation, their supermolecular structure is stabilized and there are no subsequent relaxation processes / and thus a dangerous voltage can occur which can lead to the coil collapsing.

The polypropylene monofilaments prepared according to the invention are suitable for making ropes. Their use for other purposes / eg sieves is not excluded. The processability of monofilaments in the production of ropes is good; in their weaving, they do not cause surface damage due to torsion forces and thus do not reduce their strength. The ropes (made from monofilaments prepared according to the invention) are resistant to sudden changes in temperature, humidity and shock load.

The preparation of monofilaments according to the invention is illustrated by the following example:

UV-stabilized polypropylene granulate 58432 (Chemopetrol, Litvinov Chemical Works) together with a black color concentrate containing carbon black was spun on a 60 mm diameter extruder at 20 ° C. The Lxtruder was equipped with a fallen toothed worm dosing unit and a 203-hole spinning block with a 1 mm diameter nozzle. The spinning monofilaments were cooled in water at 40 °

C and drawn in two stages to a total drawing ratio of 1: 9 at a temperature of 120 to 140 ° C. The bundle 203 of elongated monofilaments | entered the fixation zone immediately after elongation at a rate of 64.5 m min ^-1 and then exited the fixation zone at a rate of 59.5 m min ^-1 . The monofilament shrinked by 8% due to the effect of circulating air at 15 ° C and a speed of 10 m min ^-1 . Monofilament residence time ▼ ·

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- The 4 fusing zone was 2 seconds · The shrinkage value of the monof11 in the zone would be given by adjusting the speed of the 7 galet withdrawal units located before and after the fusing zone. The bundle of monofilaments after withdrawal from the fixation was cooled by a 10% aqueous solution of Spolex OL (Association for Chemical and Metallurgical Production, Bolatice na Labem) / whose active ingredient is ethoxylated oleic acid. The monofilaments were then wound on reels, each with 7 monofilaments per reel. Physical-mechanical properties of prepared monofilaments were as follows: diameter 0.28 mm, strength 31.6 N, elongation 16%, boiling shrinkage in water 4% ·

Claims (1)

SUBJECT OF THE INVENTION Process for preparing polypropylene monofilaments having a diameter of 0.1 to 0.5 mm @ 2, characterized in that the coated monofilaments are drawn to a total draw ratio of 7 to 1:10 and then subjected to a flow of air at a speed of 5 to 20 m @ -1. and a temperature of 130 to 170 ° C for 0.5 to 4 seconds to shrink these monofilaments by 2 to 10% relative to the original length of the monofilaments, and then immediately cooled with water at a temperature of 10 to 30 ° C; containing surfactants.