CS252997B1 - Method of optimum stretching ratio determination with surface dyeable polypropylene fibres - Google Patents

Abstract

The solution relates to the method of determining the optimum the ratio of DPopt to surface-staining polypropylene fibers when the uptake of dyes from 80 to 90 is achieved pen. wt. The essence of the solution is determination birefringence of undrawn fiber and for determination optimum separation ratio uses the relationship DPopt = a - b (Anj wherein the empirical constants a and b are predetermined determine the dependence between birefringence various pre-oriented undirected fibers and such a proportion of them prepared spit cut fibers when the highest dye intake is achieved. sposob determining the optimal scaling ratio surface-resistant polypropylene of this solution can be utilized in the development of surface-technology technologies fibers of different subtleties in small-scale production, increasing spinning performance of existing technologies as well as the transition to other types of polypropylene granulates.

Description

The present invention relates to a method of determining the optimum draw ratio for surface-dyable polypropylene fibers.

The process for preparing surface-dyable nitrogen-modified ethylene-acrylate modifiers of modified polypropylene fibers consists of two main stages. In the first stage, the modifiers are added to polypropylene, which is spun and non-crosslinked fibers are prepared. In the second stage, the fibers are unidirectionally deformed and oriented fibers are obtained, wherein the draw ratio is determined based on achieving the desired mechanical properties. In the surface dyeing of the modified polypropylene fibers thus prepared, there are often cases of weak coloring and thus insufficient use of the present modifier. This is the cause of the undesirable effect of color stiffness in textile fiber processing.

It has been found that polypropylene fibers modified with ethylene acrylate copolymers with nitrogen modifiers stain differently depending on the degree of orientation. While the non-crosslinked fibers only dye in the surface layer, as the draw ratio increases, the color of the inner regions increases and the amount of stably bound dye increases. Again, after a certain weight ratio is exceeded, there is a decrease in the color of the fibers. An increase in dye uptake in highly oriented fibers cannot be achieved either by adjusting the dye bath or by extending the dyeing time. Accordingly, there is one optimum dye ratio for surface-color polypropylene fibers in terms of dyeing, whereby the entire cross-section of the fiber can be precoloured and the modifier present can be sufficiently utilized while the amount of stably dye is from 80 to 90% by weight. The optimum ratio of surface-dyeable polypropylene fibers is related to the overall pre-orientation of the non-crosslinked fibers. In order to achieve the same color effect, it is necessary to utilize the oriented fibers to a higher grain ratio while the pre-oriented fibers to a lower grain ratio. Such behavior of surface-colored polypropylene fibers in the surface dyeing process is not in accordance with the prior art knowledge of the dyeing process of polyester, polyamide and polyacrylonitrile fibers. In these types of fibers, the non-woven fibers are best dyed and, with a gradual increase in the draw ratio, their coloring ability gradually decreases.

The principle of the solution is a method of determining the optimum drawing ratio DP _opt for surfaces _dyeable with nitrogen modifiers of modified polypropylene fibers, where the uptake of dyes from 80 to 90% by weight is achieved. The solution is to determine the birefringence of the ížη fiber and use the relation,

DP _opt = a - b (Anj in which the empirical constants a and b are predetermined by the relationship between the birefringence of the spice-preoriented non-bristled fibers and the deterioration ratio of the spice-derived fibers prepared therefrom, .

The surface-colored polypropylene fibers prepared under different spinning conditions, split on the DP _opt , dye uniformly throughout the cross-section and the amount of stably bound dye is merely a function of the content of the modifier present. Their mechanical properties are suitable for further textile processing. Furthermore, it is advantageous to determine the DP _opt when switching to other types of polypropylene granulates, as well as to change the performance of the winding machines. The DP _opt method for surface-colorable polypropylene fibers according to this solution can be applied in the context of the introduction of small-scale production of specialty fiber types.

Example 1

To the melt polypropylene (type TE 430 with a flow index of 25 g / 10 min) was added 8 wt% copolymer of ethylene acrylate with amine groups containing 2.2 wt% nitrogen. After homogenization in a dynamic mixer, such a melt was spun at 260 ° C. C and a number of different levels of the outlet at _the and of the winding W _L rate. Nedížené modified polypropylene fiber is Dizili for any drawing stage conditions of 130 ° C. the thus prepared fiber was dyed from a bath containing acid dyes Sumlnol Fast Blue PR at 2% by weight of the It was found that fibers with the same modifier content and different degrees of orientation contained different amounts of stably bound dye, as shown in Table 1.

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Table 1

Cond. The spun. die draw ratio Pull-out. Farb. bath [%] strength [CN / dtex] tensibility [%] Δη. 10 ³ Sun. fiber DP _op t In _the ~ 13.72 m. min ^-1 1: 2.5 40.1 2.3 85.5 1: 3.0 62.3 2.7 48.1 In _L - 400 m. min ^-1 1: 3,5 83.0 3.1 41.5 3.7 1: 4.0 1: 4.0 90.1 3.8 36.3 1: 4,5 83.2 4.4 34.7 V _o = 20.58 m. min ^-1 1: 2.5 45.3 2.5 61.3 1: 3.0 67.1 2.9 58.2 _H = 600 m. min ^-1 1: 3,5 83.5 3.2 48.3 5.1 1: 38 1: 4.0 88.1 3.8 40.2 1: 4,5 79.0 4.5 30.1 At _o - 27.44 m. min ¹ 1: 2.5 55.1 2.6 62.4 1: 3.0 70.3 3.0 59.2 _H = 800 m. min ^-1 1: 3,5 88.1 3.4 45.4 6.2 1: 3,7 1: 4.0 82.3 3.9 35.5 1: 4,5 79.4 4.5 29.3 V _o = 34.30 m. min ' ¹ 1: 2.5 51.5 2.8 64.7 1: 3.0 68.2 3.1 53.8 _L = 1000 m. min ¹ 1: 3,5 89.1 3.5 41.7 8.1 1: 3,6 1: 4.0 87.2 3.9 32.3 1: 4,5 75.1 4.6 26.2 H _o ~ 41.16 m. min ' ¹ 1: 2.5 75.1 2.9 65.0 1: 3.0 90.3 3.6 43.5 8.8 1: 3,4 _H = 1200 m. min ^-1 1: 3,5 88.1 3.9 25.1 1: 4.0 78.2 4.7 23.5

The DP _opt values given in Table 1 for the different spinning conditions were determined from the graphical dependencies of the dyeing bath yield and the individual fiber draw ratio. Mutual relations between birefringence of undrawn fibers and determined DP _opt were processed by the method of linear regression into relation

DPopt = a - b (An) where a = 4,3608 and b = 103,5771 with a correlation coefficient of 0,973. The relationship thus obtained is applicable to the calculation of the optimum retention ratio in terms of the dyeability of the surface-colored polypropylene fibers when changing the spinning technological conditions on the same spinning apparatus or when changing the molecular weight of the granulate.

Example 2

The surface-dyed polypropylene fibers were prepared as in Example 1 using a polymer with IT = 24.16 g / 10 min, to which 8 wt. % copolymer of ethylene acrylate with amine groups containing 1.95 wt. nitrogen. At a dosage of 25 g / min, undrawn fibers were prepared at variations in the draw rates as shown in Table 2. Fibers with different degrees of pre-orientation evaluated by birefringence were obtained. According to the relation given in Example 1, optimally ratio ratios for which the prepared fibers were utilized were calculated. The amount of stably bound dye was determined according to the dyeing procedure as in Example 1.

Table 2

V _L [m / min] Δη. 10 ³ nedlž. fiber DP _O pt Coloring bath yield (%] 947 11.69 3.15 86.8 728 9.94 3.33 89.3 653 8.82 3.44 88.2 591 8.16 3.51 90.4 541 6.44 3.69 91.3

The surface-dyable fibers prepared by spinning at different take-off speeds and cut to DP _opt are dyed with a high bath yield.

3 2 0 7

Example 3

Surface-dyeable polypropylene fibers were prepared as in Example 1 using polypropylene granules of different molecular weight characterized by a flow index. With a feed rate of 25 g / min and a draw-off speed of 591 m / min, non-woven fibers were prepared which had a different birefringence as a result of their different pre-orientation. Based on the relationship in Example 1, optimally ratio ratios were calculated. The fibers loaded on the DP _opt were subjected to a dyeing process in accordance with the procedure in the previous examples. The results of determining the amount of stably incorporated dye are shown in Table 3.

Table 3

Flow index η. 10 ³ [g / 10 min] no load. fiber

43.66 5.78

24.16 8.16

20.73 12.57

Surface - colored fibers prepared from polypropylene granules with different

DPopt Dye bath yield [%] 3.76 87.3 3.51 88.2 3.06 86.5

the flux index and dotted to the DP _opt are stained at the desired intensity.

Claims (1)

Ways to determine the optimum die draw ratio DT of _optical povrchovofarbiteíných nitrogenous modifiers modified polypropylene fiber intake dyes 80-90 wt.%, Characterized by determining the birefringence An nedíženého fibers and to determine the optimum die draw ratio DT _IP link is used t Y N O L E Z U DP _opt = a - b (An), in which the empirical constants a and b are predetermined depending on the relationship between the birefringence of the pre-oriented non-regrinded fibers and such a draw ratio of the different fiber fibers prepared therefrom to achieve the highest dye uptake.