WO2015052070A1

WO2015052070A1 - Spinneret for extruding self-crimping hollow fibers, self-crimping hollow fibers, and method for producing self-crimping hollow fibers

Info

Publication number: WO2015052070A1
Application number: PCT/EP2014/071141
Authority: WO
Inventors: Erwin Glawion; Horst Finder
Original assignee: TRüTZSCHLER GMBH & CO. KG
Priority date: 2013-10-08
Filing date: 2014-10-02
Publication date: 2015-04-16
Also published as: RU2016117271A; US20160265141A1; EP3055450A1; DE102013016628A1; CN105637128A

Abstract

The invention relates to a spinneret (1) for extruding self-crimping hollow fibers, comprising at least one capillary (18). The at least one capillary (18) has at least one segmented opening (16), which has at least two opening segments (20, 22) spaced apart from each other in the cross-section, wherein a first opening segment (22) of the at least two opening segments (20, 22) has a first opening-segment width (32) and a second opening segment (20) of the at least two opening segments (20, 22) has a second opening-segment width (34), wherein the second opening-segment width (34) is wider than the first opening-segment width (32).

Description

Spinneret for extruding self-curling hollow fibers and self-curling hollow fibers and method for producing self-curling hollow fibers

The invention relates to a spinneret for extruding hollow fibers according to the preamble of claim 1, a self-crimping hollow fiber according to the preamble of claim 8 and a method for producing self-crimping hollow fibers according to claim 14.

Self-curling hollow fibers are known from the prior art, which are extruded by means of a spinneret. Spinnerets with capillaries are known, each capillary having a C-shaped opening. From the C-shaped opening, a hollow fiber profile is extruded. After emerging from the opening, the ends of the extruded C-shaped hollow fiber profile in the form of a hollow fiber wall section melt together by fusion and form a hollow fiber with a hollow fiber wall. After stretching the hollow fibers, these curl 3-dimensionally due to resulting spin orientations. Furthermore, such selbstkräuselnden hollow fibers can be generated by the additional simultaneous feeding of two melt streams, which also lead to spin orientations. These fibers have a significantly higher crimp intensity, but require a much more complex system technology and thus significantly higher investment. The invention has for its object to provide selbstkräuselnde hollow fibers, a spinneret for extruding selbstkräuselnden hollow fibers and a method for producing self-curling hollow fibers, wherein the Kräuselintensität the hollow fibers produced is improved with a single melt stream and the hollow fibers produced in a simple manner can be.

To achieve this object, the features of claims 1, 8 and 14 serve.

The invention advantageously provides a spinneret, wherein the spinneret has at least one capillary with segmented opening, which has at least two spaced apart opening segments in cross section, wherein a first opening segment of the at least two opening segments has a first opening segment width and a second opening segment of the at least two Opening segments having a second opening segment width, wherein the second opening segment width is wider than the first opening segment width.

Due to the different width of the opening segments flow different amounts of melt through the capillary, creating a hollow fiber with asymmetrically shaped hollow fiber walls with different wall thickness and curvature and different spin orientations. The hollow fibers produced in this way have the advantage that they have a very high Kräuselintensität after hiding.

The opening segment width of the second opening segment is preferably at least 10%, in particular at least 20% wider than the opening segment width of the first opening segment. The hollow fibers produced by means of such a spinneret have after stretching particularly good crimping properties or a particularly high Kräuselintensität.

The opening segment width of the second opening segment is preferably 10 to 50%, in particular 20 to 40% wider than the opening segment width of the first opening segment. Differences in the opening segment width in these sen areas have the advantage that hollow fibers are produced, which have particularly high Kräuselintensitäten.

The opening segments may be arcuate round, but also oval or angular.

The at least two opening segments can each be designed to be substantially semicircular in a particularly advantageous manner.

The respective opening segments may have two longitudinal sides and two transverse sides, the distance between the transverse sides of the adjoining opening segments being selected such that the hollow fiber wall sections extruded from the opening segments merge on the transverse sides after emerging from the opening segments.

The opening segment width of the respective opening segments is preferably constant, i. consistently.

It is also possible to provide segmented openings with at least three or at least four opening segments, wherein at least one first and one second opening segment are provided, which have different opening segment widths.

In the case of a hollow fiber having a hollow fiber wall which is extruded by means of a spinneret, wherein the hollow fiber wall has at least two hollow fiber wall sections in cross section, it may be advantageously provided that a first of the at least two hollow fiber wall sections has a first wall thickness and a second of the at least two Hollow fiber wall sections having a second wall thickness, wherein the second wall thickness is greater than the first wall thickness.

Such a hollow fiber produced is a self-crimping hollow fiber due to the spinning orientations created by the melt flow through the capillary. The at least two hollow fiber wall sections can each have a constant wall thickness over the respective hollow fiber wall section, ie. they each have a constant wall thickness.

The first hollow fiber wall section may have a constant wall thickness. The second hollow fiber wall section may have a constant wall thickness.

The first hollow fiber wall portion and the second hollow fiber wall portion are connected to each other by fusing. This means that the at least two hollow fiber wall sections are each connected by fusing with the adjacent hollow fiber wall sections.

The wall thickness of the second hollow fiber wall section may be at least 10%, preferably at least 20%, greater than the wall thickness of the first hollow fiber wall section.

The wall thickness of the second hollow fiber wall section can be larger by 10 to 50%, preferably by 20 to 40%, than the wall thickness of the first hollow fiber wall section. In such wall thickness ratios, the hollow fiber wall sections have particularly good räuselintensitäten.

The first hollow fiber wall portion and the second hollow fiber wall portion may be made of the same material. The hollow fiber may thus be a mono-component hollow fiber.

In a less advantageous embodiment, the first hollow fiber wall portion and the second hollow fiber wall portion may be made of different materials. The hollow fiber can thus also be a bi-component hollow fiber.

The hollow fiber wall sections may be curved, wherein the second hollow fiber wall section may be more curved than the first hollow fiber wall section. A hollow fiber with two hollow fiber wall sections preferably has a "D" -shaped cross-section. It can also be provided hollow fibers having at least three or at least four hollow fiber wall sections. In this case, at least one first and one second hollow fiber wall section can be provided, which have different wall thicknesses.

According to the present invention, a method for producing hollow fibers by means of a spinneret can be provided, comprising the following method steps:

Extruding polymer material from a cross-sectionally segmented opening of a capillary of a spinneret, the opening having at least two opening segments having different opening segment widths, at least two hollow fiber wall sections being extruded from the at least two opening segments, each extruding a hollow fiber wall section from each opening segment,

Melting the extruded hollow fiber wall sections after emerging from the opening to form a hollow fiber having a hollow fiber wall having in cross-section at least two hollow fiber wall sections with different wall thicknesses. The hollow fiber wall sections are thus connected to each other by self-melting.

The hollow fiber can be heated after the fusing together, which again improves the crimp intensity by Nachschrumpfen. The smaller the individual curling arches, the more intense is the curling intensity.

The molten hollow fiber can be cooled and drawn. The undrawn hollow fiber is preferably still smooth, after pulling or hiding the hollow fibers are crimped.

In the following, embodiments of the invention will be explained in more detail with reference to the drawing. They show schematically:

1 shows an apparatus for producing staple fibers,

2 is a bottom view of a spinneret,

Fig. 3 a segmented opening of the capillary,

Fig. 4a shows a hollow fiber in cross-section,

Fig. 4b a hollow fiber in cross section,

Fig. 5a-5d Comparison of curling intensities of different

Hollow fibers,

Fig. 1 shows an apparatus for producing staple fibers. Polymeric material may be arranged in a container 8. After drying in a drying device 6, the porous material can be melted in a melting device 4. This molten material is pressed in a spinneret 1 by capillaries. The melt is pressed through pressure and measuring pumps through the capillaries and withdrawn in the form of filaments or fibers. After emerging from the spinneret, the filaments in an injection shaft, not shown, in the region 12 by means of z. B. air cooled and they can then be wound up at a constant speed on drums or stored in cans. The filaments can then be drawn directly or later in drawers 12, 14. In the present case, the filaments are hollow fibers 2.

The spinneret 1 is shown in detail in Fig. 2 in the bottom view. The spinneret has a plurality of capillaries 18. The capillaries 18 are the nozzle holes. As shown in FIG. 2, the capillary 18 has at least one segmented opening 16. The segmented opening 16 has at least two spaced-apart opening segments 20, 22 in cross-section. From Fig. 2 is to be assume that the spinneret has a plurality of capillaries, from each of which hollow fibers can be extruded. The respective capillaries are constructed identically so that a multiplicity of the same hollow fibers can be extruded.

The segmented opening 16 of the capillary 18 shown in detail in FIG. 3 has opening segments 20, 22 spaced apart from one another. The first opening segment 22 of the at least two opening segments 20, 22 has a first opening segment width 32. The opening segment width is preferably determined in the radial direction of the opening 16. The second opening segment 20 of the at least two opening segments 20, 22 has a second opening segment width 34. The second opening segment width 34 is wider than the first opening segment width 32. Preferably, the opening segment width of the second opening segment 20 is at least 10%, in particular at least 20% wider than the opening segment width 32 of the first opening segment 22.

Most preferably, the opening segment width 34 of the second opening segment 20 is 10% to 50%, preferably 20% to 40% wider than the opening segment width 32 of the first opening segment 22.

Preferably, the opening segments 20, 22, as in the illustrated embodiment, formed arcuate. Furthermore, the opening segments 20, 22 are preferably curved concentrically. The opening segments 20, 22 are preferably concentrically curved about the center 24 of the opening 16. Likewise, the opening segments 20, 22 are each preferably substantially semicircular in shape.

The respective opening segments 20, 22 each have longitudinal sides 28 and transverse sides 30. Between the transverse sides 30 each webs 26 are arranged.

In the method for producing self-curling hollow fibers 2 by means of the spinneret 1, the polymeric material is extruded from the cross-sectionally segmented opening 16 of the capillary 18 of the spinneret 1. From the opening Segments 20, 22, a hollow fiber wall section 40, 42 is extruded in each case. Because the first opening segment 22 and the second opening segment 20 have different opening segment widths 32, 34, the hollow fiber wall sections 40, 42 extruded from the respective opening segments 20, 22 also have different wall thicknesses. After exiting the opening 16, the extruded Hohifaserwandabschnitte 40, 42 merge together, wherein the areas merge, which are arranged in the region of the transverse sides 30 of the opening segments 20, 22. The Hohifaserwandabschnitte 40, 42 thus also merge in the region of their transverse sides together, so that a hollow fiber 2 is formed with a hollow fiber wall, which has two Hohifaserwandabschnitte 40, 42 with different wall thicknesses in cross section.

The distance between the transverse sides 30 of the opening segments 20, 22 is selected such that the Hohifaserwandabschnitte 40, 42 can merge after exiting the opening to each other. The extruded Hohifaserwandabschnitte 40, 42 connect by fusing together.

In Fig. 4a shows a macroscopic image of cross-sections of hollow fibers 2 according to the invention. FIG. 4b shows an enlarged representation of a cross section of a hollow fiber 2 according to the invention.

Like the Fign. 4a and 4b, the hollow fiber has a hollow fiber wall 48. The hollow fiber wall 48 has at least two Hohifaserwandabschnitte 40, 42 in cross section. In the illustrated embodiment, a hollow fiber wall 48 with two hollow fiber wall sections 40, 42 is shown. However, it could also be provided more than two Hohifaserwandabschnitte.

The first hollow fiber wall section 40 has a first wall thickness 44 and the second hollow fiber wall section 42 has a second wall thickness 46. The second wall thickness 46 of the second hollow fiber wall section 42 is greater than the first wall thickness 42 of the first hollow fiber wall section.

Both the wall thickness 44 of the first hollow fiber wall section 40 and the second wall thickness 46 of the second hollow fiber wall section 42 are each preferably constant or constant. The consisting of two hollow fiber wall sections 40, 42 hollow fiber wall 48 from the illustrated embodiment preferably has a D-shaped cross-section. The second hollow fiber wall section 42, which has the thickness wall thickness 46, curves more strongly than the first hollow fiber wall section 40 with the smaller wall thickness 44. This produces a D-shaped hollow fiber cross section. This is particularly advantageous for the self-crimping properties of the hollow fiber.

The first hollow fiber wall portion 40 and the second hollow fiber wall portion 42 are joined together by fusing. This is the prerequisite for the Kräuselintensität the hollow fiber. The hollow fibers 2 produced by means of a spinning process preferably receive the crimp after being stretched with, for example, the drafting devices 12, 14.

In the Fign. 5a to 5d hollow fibers are shown after stretching. The fibers were glued on blackboards and compared qualitatively. Relevant are only the crimped sections. The straight sections are undrawn fibers because the patterns were drawn by hand.

In Fig. 5a, a hollow fiber is shown, which has been produced with a spinneret, wherein the capillary of the spinneret had a segmented opening, which had in cross-section spaced apart opening segments. The opening segment widths of the respective opening segments were the same.

In Fig. 5b shows a hollow fiber which was produced under the same experimental conditions as the hollow fiber according to FIG. 5a, but with the difference that a spinneret according to the invention was used whose capillaries had a segmented opening with two opening segments with different opening segment widths. The second opening segment width of the second opening segment was 20% wider than the opening segment width of the first opening segment.

In Fig. FIG. 5c shows a hollow fiber which has been produced under the same experimental conditions as the hollow fibers according to FIGS. 5a and 5b, but with the FIG Difference in that the segmented opening of the respective capillary in cross section has a first opening segment and a second opening segment, wherein the opening segment width of the second opening segment was 40% wider than the opening segment width of the first opening segment.

As can be clearly seen in FIGS. 5b-5c, the curl intensities of the hollow fibers which have been produced by spinnerets according to the invention whose opening segments have different widths are considerably stronger than the curl intensity according to FIG. 5a, recognizable by the many small curled arcs.

Furthermore, the hollow fiber according to FIG. 5c had a slightly higher crimp intensity than the hollow fiber according to FIG. 5b. The hollow fibers according to FIGS. 5b and 5c both each had a hollow fiber wall with at least two hollow fiber wall sections, the wall thickness of the first hollow fiber wall section and the wall thickness of the second hollow fiber wall section being of different sizes.

In the experiments it was found that when the opening segment width of the second opening segment was at least 5%, preferably at least 20% wider than the opening segment width of the first opening segment, the crimping intensity was particularly good.

Further, it was found that when the opening segment width of the second opening segment was 5% to 50%, preferably 20% to 40% wider than the opening segment width of the first opening segment, the curl intensity was particularly advantageous.

It has also been found that when the wall thickness of the second hollow fiber wall section was greater than the wall thickness of the first hollow fiber wall section by at least 5%, preferably at least 20%, the crimp intensity was also particularly advantageous.

Further, it was found that when the wall thickness of the second hollow fiber wall section was larger by 5% to 50%, preferably by 20% to 40% the wall thickness of the first hollow fiber wall section, the hollow fibers had particularly good Kräuselintensitäten.

The present invention has the advantage that even with mono-component hollow fibers, particularly good self-curling properties were present.

Due to the different opening segment widths of the opening segments, different amounts of melt flow out of the opening segments, which stick together after emerging at the respective ends of the hollow fiber wall sections and form a hollow fiber. Such a hollow fiber preferably has a D-shaped cross-section. Each of the hollow fiber wall sections has a different spin orientation, resulting in different stretch and shrink behavior. This asymmetry leads to self-crimping of the fibers after stretching. The above ratios of opening segment widths and different wall thickness ratios were particularly advantageous.

In Fig. 5d is still a C-shaped self-crimping hollow fiber at the same spinning conditions shown. While this C-shaped self-crimping hollow fiber Fig. 5d has large and relatively flat crimps, the hollow fibers are Figs. 5b and 5c with the small and high bows much more intense curled. This results in a higher bulk, which in turn means less filling weight for a given volume and thus lower costs in applications as filling fiber.

Claims

claims

Spinneret (1) for extruding self-crimping hollow fibers,

- With at least one capillary (18), characterized in that

- The at least one capillary (18) has at least one segmented opening (16) in cross-section at least two spaced apart opening segments (20, 22), wherein a first opening segment (22) of the at least two opening segments (20, 22) has a first Opening segment width (32) and a second opening segment (20) of the at least two opening segments (20, 22) has a second opening segment width (34), wherein the second opening segment width (34) is wider than the first opening segment width (32).

Spinneret (1) according to claim 1, characterized in that the opening segment width (34) of the second opening segment (20) is at least 10%, preferably at least 20% wider than the opening segment width (32) of the first opening segment (22).

Spinneret (1) according to claim 1 or 2, characterized in that the opening segment width (34) of the second opening segment (20) is 10% to 50%, preferably 20% to 40% wider than the opening segment width (32) of the first opening segment (22) is.

Spinneret (1) according to one of claims 1 to 3, characterized in that the opening segments (20, 22) are arcuate.

Spinneret (1) according to one of claims 1 to 4, characterized in that the opening segments (20, 22) are concentrically curved. Spinneret (1) according to one of claims 1 to 5, characterized in that the at least two opening segments (20, 22) are each formed substantially semicircular.

Spinneret (1) according to one of claims 1 to 6, characterized in that the respective opening segments (20, 22) have two longitudinal sides (28) and two transverse sides (30), wherein the distance between the transverse sides (30) of the adjacent opening segments (20, 22) is selected such that the hollow fiber wall sections (40, 42) extruded from the opening segments (20, 22) melt on the transverse sides after emerging from the opening segments (20, 22).

Self-crimping hollow fiber (2), which is extruded by means of a spinneret (1), with

- A hollow fiber wall (48), characterized in that the hollow fiber wall (48) in cross section at least two hollow fiber wall sections (40, 42), wherein a first (40) of the at least two hollow fiber wall sections (40, 42) has a first wall thickness (44) and a second (42) of the at least two hollow fiber wall sections (40, 42) has a second wall thickness (46), the second wall thickness (46) being greater than the first wall thickness (44).

Selbstkräuselnde hollow fiber (2) according to claim 8, characterized in that both the first hollow fiber wall portion (40) and the second hollow fiber wall portion (42) each having a constant wall thickness.

10. Selbstkräuselnde hollow fiber (2) according to claim 8 or 9, characterized marked ^¬ characterized in that the first hollow fiber wall portion (40) and the second hollow fiber wall portion (42) are interconnected by fusing.

11. Selbstkräuselnde hollow fiber (2) according to one of claims 8 to 10, characterized in that the wall thickness (46) of the second hollow fiber wall portion (42) by at least 10%, preferably at least 20% greater than the wall thickness (44) of the first Hollow fiber wall section (40).

12. Selbstkräuselnde hollow fiber (2) according to any one of claims 8 to 11, characterized in that the wall thickness (46) of the second hollow fiber wall portion (42) by 10% to 50%, preferably by 20% to 40%, greater than the wall thickness (44) of the first hollow fiber wall section (40).

13. Self-crimping hollow fibers (2) according to any one of claims 8 to 12, characterized in that the hollow fiber wall portions (40, 42) are curved, wherein the second hollow fiber wall portion (42) is curved more than the first hollow fiber wall portion (40).

14. A method for producing selbstkräuselnden hollow fibers (2) by means of a spinneret (1), through

- extruding polymeric material from a segmented opening (16) of a capillary (18) of a spinneret (1), the opening (16) having at least two opening segments (20, 22) with different opening segment widths (32, 34),

wherein at least two hollow fiber wall sections (40, 42) are extruded from the at least two opening segments (20, 22), in each case one hollow fiber wall section (40, 42) being extruded from each opening segment (20, 22),

- Melting of the extruded hollow fiber wall sections (40, 42) after emerging from the opening (16) to form a hollow fiber having a hollow fiber wall (48) having in cross-section at least two hollow fiber wall sections (40, 42) with different wall thicknesses (44, 46).

A method according to claim 14, characterized in that the hollow fiber (2) is heated after the melting together.