CS259278B1 - A method of producing polypropylene-based composite fibers with controlled limestone dispersion - Google Patents

Abstract

The solution concerns a method of producing composite fibers based on polypropylene with controlled dispersion of limestone. The essence of the solution is to regulate the degree of dispersion by defined main technological parameters of production, affecting the dispersion of limestone in the polypropylene matrix, i.e. temperature and shear rate during spinning, satisfying the relationship: SD = 9.68 + 0.025 . t. [1—e(-°·002 · D) ] where SD is the degree of dispersion of limestone in polypropylene composite fibers, t is the spinning temperature in 0 °C and D is the shear rate during spinning in s-1.

Description

259273

The present invention relates to a process for the production of polypropylene based composite fibers with controlled limestone dispersion.

It is known that the addition of various dispersants, such as CS AO 220 957, as well as the positive effect of some dispersants on dispersing fillers in composite plastics products such as CATZ, HS: Napolnitel, can be achieved by improving the dispersion of pigments in the polypropylene fibers in the mass. dl'a polimernychkompozicionnych materials. Translation, Moskva, Chimija 1981.

However, there is no known method of controlling the dispersion of limestone in composite polypropylene fibers by the technological parameters of their production.

The essence of the present invention is the production of polypropylene composite fibers with a controlled dispersion of calcium with a particle size of up to 10 microns with a limestone content of 1.0 to 30% by weight. The limestone dispersion control regulates, by a defined choice, two basic technological parameters influencing the limestone dispersion in the polypropylene fibers in the process of their formation, i.e. the temperature and the shear rate during spinning. The degree of dispersion of the SD limestone in the com- posite fiber is controllable by the following: SD - 9.68 + 0.025. t. [1 — e (002 ° DJ)] with a variation from an experimentally determined dispersion range of less than 6 ° / o, where t is the spinning temperature in ° C, and D is the spinning shear rate in s_1.

This relationship is valid for the filament temperature range of 210 to 300 ° C and the shear rate range of spinning from 100 to 2500 s-1 and was determined by the non-linear regression method, with the sum of squares of absolute deviations with a determination index of 0.92. The degree of SD dispersion is determined by the author's certificate 259 257, "Method for Determining Limestone Dispersion in Polypropylene Fibers".

The present invention provides a new process for the production of composite polypropylene fibers with controlled limestone dispersion, which is achieved by a defined choice of basic fiber forming technology parameters.

Said process allows the preparation of composite polypropylene fibers by the desired dispersion of limestone in the fiber bed. At the same time, it is possible to find optimum basic technological conditions for the formation of fiber on a given device, whereby the highest degree of limestone dispersion is achieved, and thus the highest reliability of the fiber formation process and the highest uniformity of the physical-mechanical properties of the composite polypropylene fibers. Přikladl

From a mixture of isotactic polypropylene of a degraded type with a locus index of 23.8 g / 10 min. and micronized limestone having an average particle size of 2.8 microns and a weight fraction of particle size below 10 microns of 0.96, an unbleached 10% by weight polypropylene composite fiber was prepared by spinning. They shared the overall ratio of 1: 3.5. The unit length weights of the composite polypropylene fibers were 4.2 dtex. A spinneret having a hole diameter of 1 mm, a spinning nozzle 400, a spinning temperature of 230 ° C and a shear rate of 200 s -1 was used. The method of Fourier transform spectroscopy (FT-IRJ hol determined degree of dispersion of SD = 11) 3. The calculated dispersion rate of the equation is SD = 11.58 Example 2

As in Example 1, the composite polypropylene fibers were prepared using a spout with a hole diameter of 0.5 mm, a spinneret spout 100, a fibrillation temperature of 230 ° C and a shear rate of 1000 s -1. The FT-IR method was used to determine the degree of limestone dispersion SD = 14.4. The value of the degree of dispersion calculated is SD = 14.69. The increased degree of dispersion degree documents the positive influence of the shear rate on the dispersion of limestone in the polypropylene composite fibers. Example 3

The composite polypropylene fibers were prepared as in Example 1 using a 1 mm diameter bore, a spinneret 400, a 270 ° C filament and a 500 s -1 shear rate. The FT-R method determined the degree of limestone dispersion SD = 14.4. The calculated value of the degree of dispersion according to is is SD = 13.98. The increased level of limestone dispersion compared to Example 1 documents the positive effect of increased shear rate and spinning temperature in the preparation of composite polypropylene fibers. Example 4

Composite polypropylene fibers were prepared as in Example 1 using a 0.5 mm diameter hole, a spinning die 100, a 270 ° C spinning temperature, and a shear rate.

Claims (1)

Process for producing polypropylene-based composite fibers with controlled limestone dispersion, characterized in that a polypropylene melt containing from 0.1 to 30% by weight of limestone with a particle size of up to 10 microns is spun according to the desired degree of dispersion of SD limestone range from 210 to 300 ° C at a shear rate D in the range from 100 to 2500 s ^-1 according to the formula: SD = 9.68 + 0.025. t. [1 — e ( ^{at 002 u} )]