CS268581B1 - Process for producing polypropylene for polypropylene fibers - Google Patents

Abstract

Method of producing polypropylene for polypropylene fibers by controlled dehydration initiated by organic peroxides in the presence of a stabilizing system containing phenolic antioxidants, thiodipropionic acid esters, light stabilizers and optionally other processing additives. The processing properties in this case are determined by the combination of phenolic antioxidants of the sterically protected and unprotected type used, which makes it possible to reduce the concentration of the air stabilizer, which is a thiodipropionic acid ester, to 0.01 to 0.049 parts by weight. This improves the whiteness of the polymer during granulation and reduces the formation of fumes during processing of degraded polypropylene. The effectiveness of light stabilizers based on sterically protected amines is also increased and the economy of polypropylene production is improved.

Description

CS 268501 B1

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polypropylene for polypropylene sheaths controlled by degradation of organic hydroxides by the addition of 11% solids to this phenolic phenolic antioxidant, thiodipropionic esters, light stabilizers and processing aids. By monitoring the properties of the polypropylene prepared in stage AO 229 766, it was found that the protected properties of the protected combination of a sterically protected and unprotected phenolic antioxidant allow the sulfur concentration of the sulfate to be reduced in comparison with the procedure of AD 229 766, the addition thereof in an amount of 0.1 to 0, 55 wt. In addition to the dyeing of the polymer in its granulation, the higher concentrations are the source of development in the processing of polypropylene into fibers. It has also been found that higher concentrations of redistearyl thiodipropionate impair the effectiveness of sterically hindered amine light stabilizers which are highly effective in protecting mass-dyed fibers against light blurring.

This drawback is solved by an improved process for the production of polypropylene for polypropylene fibers controlled by peroxidically initiated degradation, whereby the concentration of thiodipropionic acid esters at a level of 0.01 to 0.049 wt. other components of the stabilization system and the entire preparation process.

The improvement according to the invention significantly reduces the non-fibrous formation in the polymer, reduces the tendency of the polymer to smoke during processing, reduces the tendency of the yellowish-colored granule to form and allows the application of high-efficiency light stabilizers based on hindered amines. By reducing the concentration of thiodipropionic acid esters, an improvement in the economical balance of the production of polypropylene for fibers is also achieved.

The example below illustrates the preparation and conditions for the preparation of polypropylene modified molecular weight fibers. Example

100 parts by weight of powder-isotactic polypropylene with an IT flow index value (determined according to ČSN 64 0861) mentioned in Table 1 were charged into the zinc-slow-moving mill. Additives and initiator were mixed into the polypropylene powder in the amounts shown in Table 1 for each case. The following additives were used:

phenolic antioxidant 2,6-di-tert-butyl-4-methylphenol, ref. I. phenolic antioxidant 2,6-dimethyl-4-dodecane (propen-1-yl-phenol. II. Phenolic antioxidant 1,3,5-tris / 3,5-di-tert-butyl-4-hydroxybenzyl / isocyanurate. distearyl thiodipropionate IV, a light-stabilized piperidine-amine-based amine with the commercial name Chimassorb 944 (v) light stabilizer 2-hydroxy-4-n-octyloxybenzophenone (VI) Degradation initiator 2,5-dimethyl-2,6-di-tert-butylperoxy hexane VII Processor Additive Calcium Stearate Mark VIII

The mixture was stirred for 30 minutes. After mixing, it was metered into the polypropylene powder so as to concentrate the polymer in the polymer. they reached the values given in Table 1. The polypropylene powder additive mix was fed to a twin-screw intensive kneader in which it was pumped and homogenized. From the kneader, the plasticized polypropylene was dispensed into a single-screw extruder and granulated by means of underwater chopping. The following properties were determined from granular polypropylene:

flow index 1T index degradability / ČSN 64 3050/10 induction period at 150 ° C in dryer ^ 150 induction period during irradiation in Xenoteste IPXen

Claims (1)

CS 268501 81 polypropylene fibers were prepared from the polypropylene prepared by the above method. A single-screw extruder with a screw diameter of 32 mm, a zone temperature of 260.260 260 ° C and a spinning head temperature of 260 ° C were used. The polymer was extruded through a 33-hole nozzle with a hole diameter of 0.5 mm and the fiber was pulled out at a speed of 400 m / min. The resultant fiber loading to a degree of 3.5 little fineness of 6.4 dtex. The prepared fibers were evaluated for strength decrease after 920 hours of irradiation in Xenoteste under temperate conditions. The values are given in Table e. 1. The symbols a, b, c, etc, denote polymers prepared according to 0 229 766. Table 1: the combinations of additives used, the properties of the granules and fibers in the example. No. 1 Combination i Composite additive system. wt. ITo ΙΪ g / io 10 280 Live. st. IP IP P P12 150 Xen days h cN / dtex% / II III IV V VI VII VIII 1 0,1 0,1 0,02 0,15 0,1 0,1 0,4 35,6 l, '0 61 2760 3.2 21 and 0J 0.1 - 0.40 0.15 - 0.1 0.1 0.4 38.2 i,? E 60 2770 3.1 37 2 0.15 0.1 0., 01 0.3 0.025 0.1 2.1 10.1 1.73 D 52 1820 3.2 68 b 0.15 0.1 - -0,, 30 - 0.3 0.025 0.1 .2.1 10.3 1.71 0 60 1680 3.1 60 3 0.1. 0.15 0.05 0.04 0.13 - '0.06 0.1 8.1 32.6 1.61 0 71 3070 2.9 8 c 0.1 0.15 0.05 0.25 0.13 0.06 0.1 8χ1 34.3 1.59 E 70 2640 3.0 26 0.05 0.15 o, i 0.02 0.15 - 0.03 0.1 1, '9.8 1, 56 0 68 3120 3,2 6 0,05 0,15 .0,1 0,50 0,15 - 0,03 0,1 1,9 10,3 1,61 E 66 2730 3,1 31 REVIEW OF THE INVENTION production of polypropylene for polypropylene fibers controlled by degradation of polypropylene with a flux index of 0.1 to 10 g / 10 min, initiated by organic peroxides, running at an extruder at a temperature of 180 to 280 ° C with a mean residence time of 200 to 1000 seconds in the % of stabilizing system containing 0.05 to 0.3 parts by weight of phenolic stabilizers, of which at least 1/3 and at most 2/3 formed by phenolic base stabilizers 2,6-dimethyl 1-4 - (dodene (propene) -yphenol, esters) tlodipropionic acid, 0.1 to 0.5 parts by weight of light stabilizers and processing additives, characterized in that 0.01 to 0.0% is used for degradation 49 parts by weight of thiodipropionic acid esters.