CS269532B1 - Method of products' additivation on base of polyolefins by means of solid additives - Google Patents

Abstract

Increased degree of dispersion of solids additives in polyolefins are achieved if the additive is converted into an additive ester-based dispersants bridging acids and polypropylene glycols at a concentration of 5 to 50% by weight to the additive at temperature melt up to 30 ° C higher such as the melting point of polyolefins nu.

Description

EN 269532 01 1

SUMMARY OF THE INVENTION The present invention provides a process for the additivation of polyolefin-based products with solid additives.

Typically, polyolefins are added to improve the performance properties of various solid additives, such as inorganic fillers. Inorganic fillers are used in higher concentrations of 2 to 40% by weight, pigments from hundreds of percent to 2% by weight.

Additivation of synthetic polymers to low additive concentrations is usually carried out with additive concentrates, in the production of which the most suitable equipment and technological conditions can be utilized from the smooth dispersion of the additive in a suitable carrier. In order to ensure a sufficient degree of dispersion of the solid additives in the polymers, high shear is required, which is usually achieved by lowering the kneading temperature, increasing the additive content by effective kneading devices. Such conditions cannot be assured in the processing of additive polymers. In the treatment of additive polymers, typically simpler devices and temperatures are used such that the melt has optimum rheological properties in terms of processing, e.g., fibers, films, and other articles. Despite the optimal kneading conditions, the required degree of dispersion is not always achieved, the low linear polyolefins produced by low-pressure polymerization, the mobility of which is lower than that of high-pressure polyolefins. In order to improve the degree of dispersion of the solid additives, various dispersants are added to the carriers, which in the mixing and kneading process rapidly wet the surface of the additives formed by kneading and prevent their reverse agglomeration, resp. agglomeration. In the application of many dispersing agents, flocculants in which the additives are predominantly bound by "dispersants, especially if these are uncoated or high-loft." Flocculate. For their disintegration, the most substantial shear forces are usually needed as they arise in the processing process.

This problem is solved by the present invention by adding fatty acid esters of polypropylene oxides to the polyolefins prior to or during the kneading with the additive, or the additive prior to its incorporation into the polyolefin carrier, in an amount of 5 to 50% by weight, based on the solid additive. melt temperature at most 30 ° C higher than the polyolefin melting point. The best results are obtained when the additive and the carrier are in powder form and the dispersant is applied to the polyolefin support in a suitable effective mixer, such as turbulent or fluidized mixers, and then the powder additive is added with stirring. Optimally, the amount of dispersant depends on the fineness and surface of the powder additive, and, as a rule, the amount is determined by the wettability which is characterized by the need for a dispersant to wet the additive so that the additive becomes powdery and forms beads. By further kneading the mixture in the kneader at low temperatures near the melting point of the polyolefin, a very efficient dispersion occurs. When coloring in the mass, this effect is overcome! by substantially increasing pigment silyconcentrate. An example of 30 kg of linear polypropylene powder with ITT of 12 g / 10 min is stirred in a turbulent mixer with 5 kg of stearic acid ester and polypropylene glycol with a molecular weight of polypropylene 1600. Then 15 kg of powder pigment Pigment Yellow 95 is added with stirring. is kneaded on a continuous double-spindle kneader at temperatures of 200-100-100 ° C in its zones. For comparison, concentrates without dispersant and polyethylene glycol of molecular weight 1000 were prepared by the same method as a dispersant.

Concentrates were used to stain the polypropylene fibers in the mass. The concentrates were melted and dosed at 3.33% by weight into the polypropylene melt. Both materials were homogenized and the colored polypropylene was formed into fibers. Relative dyeing strength increased compared to staining with concentrate without dispersant when applied

Claims (1)

50% by weight of stearic ester and polypropylene glycol 70%. In the microscopic examination, no coarse particles flocculously observed in comparative cases. EXAMPLE 2 5 kg of coconut ester (5 kg) and polypropylene glycol (20 kg) of Pigment Red 144 and / or 214 are added to 25 kg of low-pressure polyethylene powder, with stirring. The mixture is kneaded on a two-spindle screw kneader at 150, 50 , 50, 150 ° C and poured into strings which are cooled down to a granulate after cooling. The granulate concentrate is added at 2% by weight to the granular polypropylene in a threaded melter hopper where it is melted, homogenized, filtered and extruded into fibers. The relative dyeing strength increased by 40% by 10% by weight compared to the dispersion-free concentrate by 10% compared to the dye-concentrate concentrate of base-polyethylene glycol. DESCRIPTION OF THE INVENTION A process for the additivation of polyolefin-based products with solid additives, characterized in that the dispersion of the additive in the polyolefin with the addition of fatty acid esters of polypropylene glycols in an amount of 5 to 50 wt. is the melting point of the polyolefin. 1