CS263360B1 - Polypropylene line with increased whiteness - Google Patents

Abstract

Polypropylene fibers with increased whiteness stability contain an addition of 0.1 to 1.0% by weight of calcite with a grain fineness of up to 30 µm and 0.005 to 0.06% by weight of a stilbene benzotriazole optical brightener.

Description

263360 2

The subject of the invention are polypropylene fibers with increased brightness stability. In the prior art polypropylene fibers by means of a matting composition, a low level of whiteness is achieved. Therefore, to increase it, various optical means are used to achieve the desired whiteness, but on the other hand they are less effective in light-fastness and stability after finished products. Polypropylene fibers are known as mentioned in MS. AO 246 020 with the addition of 0.01-0.1% by weight of stilbenzotriazole optical brighteners, with which it achieves an increased whiteness effect, but in this manner, despite its increased whiteness, its stability is not achieved. Over time, there was a yellowing of the fiber and a decrease in the degree of whiteness. AO 252 013 by the addition of light stabilizers. Polypropylene fibers prepared by this process also record whiteness drop and fiber yellowing.

The drawbacks of yellowing with higher optical brightness polypropylene fibers do not exhibit fibers of the present invention which contain from 0.1 to 1.0% by weight of ground calcite grain fineness to 30 µl and 0.005 to 0.06% by weight of stilbene benzotriazole optical brightener.

The polypropylene fibers of the present invention are prepared from a melt of isotactic polypropylene to which a polypropylene concentrate containing 15% by weight of titanium dioxide, 5 to 10% by weight of calcite having a grain size of up to 30 µm, 7.5% polypropylene oil and 0% is added. 1 to 1.7% by weight of a stibenobenzotriazole optical brightener by injection method to obtain a ground calcite content of from 0.1 to 1.0% by weight of grain fineness to 30 µm and 0.005 to 0.06% by weight of an optical stilbene benzotriazole brightener in the fiber.

The mixture of the melt of the base polymer and the melt of the concentrate is homogenized, filtered and finally spun prior to entering the complete fiber spout. The prepared polypropylene fibers were evaluated on a Leukometer instrument, which sameraled the degree of whiteness expressed by the standard% MgO scale as well as the visual yellowing of the fibers. Example 1

For comparison, polypropylene fibers from isotactic polypropylene blankets were prepared. AO 252 013 with the addition of 0.03% by weight of a Hostalux KSN stilbenzotriazole optical brightener, 0.53% by weight of titanium dioxide and thermosetting stabilizers 0.05% by weight Goodrite 3114 and 0.15% by weight Chimasorb944. The prepared fibers showed a yellowing of the fiber and a decrease in whiteness from 94% to 86.4%, expressed as% MgO, by the above-mentioned post-light week standing process. Example 2

Polypropylene fibers from isotactic polypropylene were prepared with a stabilized MS. AO 252 013 as shown in Example 1, with the addition of 0.03% by weight of a Hostalux KSN stilbene benzotriazole brightener, 0.53% by weight of oxidite and 0.3% by weight of a P-15 calcite with a particle size of 15 µm.

In this way, the polypropylene fibers do not exhibit yellowing or declination after half-year observation. The initially measured whiteness was 94.2% and 94.3% MgO after day-to-day exposure and no yellowing of the fibers was observed. 3 263360 Example 3

In order to verify the effect of the thermo-light stabilizers on the brightness and stability, polypropylene fibers were prepared without the stabilizers listed in Example 1 with the addition of 0.03% by weight of the HostaluxKSN stilbene benzotriazole brightener, 0.53% by weight of titanium dioxide and 0.3% by weight of the calcite P-15 by size. up to 15 yum. The polypropylene fibers thus prepared were initially measured at 94.5% brightness and 95% MgO after half-year exposure to daylight, and no yellowing of the fibers was observed. It follows that the addition of thermo-light stabilizers according to MS. AO 252 013 has no effect on whiteness or stability. Example 4

However, as in Example 2, but with varying ratios to illustrate the efficacy range, isotactic polypropylene polypropylene fibers with the addition of 0.008 wt% stilbene benzotriazole optically brightener Hostalux KSN, 0.53 wt% titanium oxide, 0.6 wt% calcite with grain fineness were added. to 20 µm and thermo-light stabilizers 0.05% by weight Goodrite 3114 and 0.15% by weight Chimasorb 944. In the thus prepared polypropylene fibers, the brightness was 91.5% initially and 91.4% MgO after half-yearly exposure to daylight; the yellowing of the fibers observed. Example 5

However, as in Example 2, but by varying the ratios to show the efficacy range, isotactic polypropylene polypropylene fibers were added with 0.05% by weight of Hostalux KSN stilbene benzotriazole brightener, 0.53% by weight of titanium dioxide, 0.9%. calcite. For grain fineness to 10 µm and thermo-light stabilizers 0.05% Goodrite3114 and 0.15% Chimasorb 944. The thus prepared polypropylene fibers were initially measured at 95% and 95.1% MgO after a half-year exposure to daylight, and was not observed yellowing the fibers. In the examples, the thermo-light stabilizers are chemical compositions which are generally represented by chemical formulas as follows:

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Claims (1)

OBJECT OF THE INVENTION Polypropylene fibers with improved whiteness stability, characterized in that they contain an addition of 0.1 to 1.0% by weight of calcite with a grain fineness of up to 30 µm and 0.005 to 0.06% by weight of a stilbenzobenzotriazole optic brightener. Severography, n. p., MOST Price 2,40 Kčs