CS208643B1 - Method of making the arched thermally stabil rough polypropylene fibres - Google Patents

Description

(54) Method of making coiled thermally stabilized coarse polypropylene fibers

The invention relates to a process for the production of hemmed thermally stabilized coarse polypropylene fibers having a unit fineness of 17 to 200 dtex.

Natural coarse fibers, such as jute, sisal, manila, have been added with coarse chemical fibers, most notably cellulosic, most melanin, in a range of fineness of 25 to 70 dtex. Later, the synthetic synthetic staple fibers of polyamide and polypropylene have been developed, which have partially replaced the already used coarse natural and chemical cellulose fibers, in part they have become the basis for new products, e.g. nonwoven, tufted carpets.

The range of fineness of the polyamide and polypropylene coarse staples was increased to 40 to 600 dtex at a cutting length of 6 to 400 mm and the fibers dyed in the mass. Their admixture to other fibers e.g. Polyester, polyacrylonitrile or polypropylene of lower fineness provides the product with a very good feel.

The least coarse polypropylene staple fibers have become interesting because polypropylene has already been used on a large scale in the production of lining or tufted carpets in the form of tapes or spunbonded webs. The best ioh shape stability, resistance to rot and mildew have a positive effect. When synthetic fibers are used in pile and backing

208 643

208 843 parts, flooring fabrics may be used in wet areas.

Increasing the unit fineness, in particular, increases the stiffness of polypropylene fibers and reduces their compressibility under long-term loading.

Coarse, high unit fineness coarse polypropylene fibers can be prepared similar to monofilaments on continuous low-speed lines, to which undiluted fibers are pulled at 0.17 to 0.67 m / s, bundled into a cable, and then immediately divided, curved, fixed and cut the staple or, after optically separating the individual fiber strands, these are individually wound on spools, e.g. according to FP 2 257 711 (1974).

The classic method of spinning, pulling unstretched fibers and iohs by reeling them or placing them in cans at speeds of 3.4 to 13.4 m / s with separate subsequent scaling, bending and fixation, or cutting, can produce fibers of unit fineness up to 40 dtex because at a weight ratio of 5, the unit fineness of the non-woven fiber is 200 dtex, which is the upper boundary and can be placed in the watering can.

According to the present invention, it is possible to achieve the production of coarse polypropylene fibers in a conventional manner, even by omitting one production operation - dredging, up to a unit fineness of up to 200 dtex, which have proven themselves in applications in the manufacture of home furnishings. This is achieved by spinning a melt having a viscosity of from 300 to 5000 Pa.s through a spinneret having a hole diameter of from 1.0 to 2.5 mm at a discharge rate of from 0.015 to 0.040 m / s and after cooling the melt strands by air at 200 to With a 500-fold elongation, fibers with a birefringence of 5 · 1θ ~ ³ to 20.10 ^-3 , a relative strength of 1.0 to 2.5 cN / dtex at an elongation of 300 to 800% are drawn at a speed of 3.0 to 15.0 m / s.

The method of producing coarse polypropylene fibers according to the present invention represents a simplification of the manufacturing process of the quenching operation, saving energy and labor as well as investment resources. Indeed, a sufficient increase in the orientation of the macromolecules and hence sufficient strength is already achieved when the high viscosity melt fiber is formed by the flow orientation resulting in 100 and multiple elongations while smoothing. The properties achieved are fully satisfactory for use in flooring fabrics, since at the elongation up to 30%, about 50% of the strength is applied and at the elongation up to 100% to 70% the strength, which still increases with increasing tearing speed. Since the fibers are of high fineness, the ioh absolute strength is already at 30% ductility so large that it allows textile processing without the risk of deformation.

The high unit fineness has the additional advantage of reducing the pigment content in the yarn, since it is sufficient, for example, to achieve the same color shade. for fibers of 50 dtex, only 65% of the pigments required for dyeing in the mass for fibers of 17 dtex.

208 643

Example 1

Flow index 4 stereoregular polypropylene with an isotactic index of 96% is melted on a screw extruder and laterally injected with a red concentrate melt at 270 ° C and the homogenized melt having a viscosity of 751 Pa.s at 27 ° C is extruded through a 70-hole spinner. 2 mm and 8 mm channel lengths at a feed rate of 300 g / min. Melt fibers extruded from the spinneret at a speed of 0.032 m / s are withdrawn and cooled to the cans at 8.75 m / s, resulting in 273 and the birefringence increases to an average of 12.1.10. The fibers are then curled, fixed in a wet state and cut to shear. The prepared staple has a unit fineness of 81.2 dtex, a strength of 1.75 cN / dtex and a ductility of 648 / &.

Example 2

Stereoregular polypropylene of a flow index of 2.5 with an isotactic index of 96% is melted and spun at a temperature of 27 ° C from a melt having a viscosity of 1200 Pa.s on a screw spinner having a spinneret equipped with 100 spinneret holes of 1.5 mm diameter with channel length 6 mm at 250 g / min. Melt fibers extruded from the die at a rate of 0.0323 m / s are cooled down! they are pulled and reeled up to a spool at 13.8 m / β with a 430-fold elongation, increasing the average birefringence to 17.7-10. The fibers are then shaped, fixed and rewound on a spool. The prepared molded cable has a unit fineness of '31.2 dtex and a total fineness of' 3120 dtex, a strength of '2.31 cN / dtex, and an elongation of 442'

Example 3

Stereoregular polypropylene Flow Index 0.7 with an isotactic index of 95% is melted and spun at a temperature of 27 ° C and a melt viscosity of 4290 Pa.s on a screw spinner with side injection of the melt of the live concentrate through a 100-hole spinneret having apertures having a diameter 2.5 mm and channel length 10 mm. At a dosage of 500 g / min, the melt fibers are extruded at a rate of 0.023 m / s and, after cooling in an air stream, are drawn into the cans at a rate of 5.33 > Then, the fibers are twisted, fixed and cut to a staple having a unit fineness of '156 dtex, a strength of' 1.13 oN / dtex and a ductility of 736 ¢.

Claims (1)

OBJECT OF THE INVENTION Process for producing spunbond thermally stabilized coarse polypropylene fibers having a unit fineness of from 17 to 200 dtex, characterized in that a melt with a viscosity of from 300 to 5000 Pa.s is spun through a spinneret having a hole diameter of from 1.0 to 2.5 mm by a discharge 0.015 to 0.040 m / s, after cooling the melt strands with air at 200 to 500 times the elongation, fibers with a birefringence of 5.10 ^J to 20.1θ, relative strength 1, are drawn at a speed of 3.0 to 15.0 m / s, 0 to 2.5 oN / dtex at a severity of 300 to 800 " Printed by Moravian Printing Works, plant 12, Leninova 21, Olomouc Price: 2,40 Kčs