Polymeric yarns and their method of manufacture

Abstract

A method for manufacturing polymeric yarns, particularly polypropylene yarns, comprises the steps of: providing at least two spinnerets (2) operating in parallel and having respective pluralities of holes, and feeding each spinneret (2) with polymeric material that is melted and extruded to form a plurality of filaments (4) having a count between 1 and 5 den; spinning the filaments (4) delivered from each spinneret (2) to form respective multifilament semi-finished strands (5), having a count, optionally different from one another, between 100 and 1500 den; coupling and texturing by air jet at least two semi-finished strands (5), the semi-finished strands (5) passing through a nozzle (12) where they are subjected to a pressurized air jet to form a textured yarn (11) .

Description

Cross-reference to related applications

[0001] This patent application claims priority from Italian patent application no. 102024000001335 filed on January 24, 2024, the entire disclosure of which is incorporated herein by reference.Technical field

[0002] The present invention relates to polymeric yarns, particularly polypropylene yarns, and to the relative manufacturing method thereof.Background

[0003] In the polymeric yarns sector a great variety of products having different features is available to satisfy needs in various fields of application.

[0004] In particular, fancy yarns are known, such as bouclé yarn, which are essentially twisted yarns, typically composed of a core strand and of an effect strand, helically wound and twisted together.

[0005] Also known are textured yarns, obtained from processes that modify the geometrical arrangement of the filaments of which a strand is formed with respect to its axis, causing variations in the elastic properties and / or bulk of said strand.

[0006] Among the textured yarns, so-called Taslan yarns are particularly well known, obtained through air-jet texturing, where the strands are subjected to an air jet inside a nozzle.

[0007] However, the search continues for materials with innovative and original properties, particularly in terms of softness, handle and bulk, and for manufacturing and / or spinning processes that give the yarns these properties.Summary

[0008] An object of the present invention is thus to provide polymeric yarns, particularly polypropylene yarns, having particularly advantageous features, especially in terms of softness and bulk, which are suitable for a variety of uses and applications.

[0009] In accordance with these objects, the invention relates to a method for manufacturing polymeric yarns, particularly polypropylene yarns, comprising the steps of: providing at least two spinnerets operating in parallel and having respective pluralities of holes, and feeding each spinneret with polymeric material that is melted and extruded to form a plurality of filaments having a count (linear density) between 1 and 5 den; spinning the filaments delivered from each spinneret to form respective multifilament semi-finished strands, having a count, optionally different from one another, between 100 and 1500 den; coupling and texturing by air jet at least two semi-finished strands, particularly from two to six semi-finished strands, which pass through a nozzle where they are subjected to a pressurized air jet, for example with a pressure between 8 and 16 bar, to form a textured yarn.

[0010] In this way, a yarn is obtained having properties of high softness, a particularly prestigious handle and also good mechanical properties, which make it suitable for various applications in various technical sectors.

[0011] In particular, the semi-finished strands subjected to the air-jet texturing step comprise at least one central core strand and one or more effect strands arranged laterally along the central core strand.

[0012] Advantageously, the core strands pass through a wetting station located upstream of the nozzle and in which they soak up water before being fed to the nozzle where the air jet is injected.

[0013] In this way, the effect of the texturing step is further improved.

[0014] In preferred embodiments, the core strands and the effect strands are fed to the air-jet texturing step by overfeeding, being fed at a speed higher than the exit speed of the yarn from the air-jet texturing step.

[0015] In particular, the exit speed of the yarn from the air-jet texturing step is between 80 and 500 m / min; and the core strands are fed to the air-jet texturing step at a feed speed that is between 1 and 30% higher than the exit speed; and the effect strands are fed to the air-jet texturing step at a feed speed that is between 10 and 200% higher than the exit speed.

[0016] Overfeeding contributes in turn to increasing the effect of the texturing step and further improves the properties of the yarn.

[0017] Advantageously, the semi-finished strands are also subjected, preferably concurrently with the spinning step, to a stretching step, in which the semi-finished strands are provided with a toughness, defined as load in grams required to break a strand having a thickness of one den, between 2 and 7 g / den.

[0018] The invention also relates to a polymeric yarn, particularly a polypropylene yarn, comprising at least one central core strand and one or more effect strands arranged laterally along the central core strand; wherein the core strands and the effect strands have a count, optionally different from one another, between 100 and 1500 den and are formed of respective pluralities of filaments having a count between 1 and 5 den; and wherein the yarn is an air-jet textured yarn.

[0019] The yarn in accordance with the invention is suitable for various applications and can be used, for example: in the clothing sector (particularly for knitwear and fabrics); in clothing accessories (bags, shoes, belts, etc.); in furnishing fabrics (orthogonal, jacquard, knitted fabrics, etc.); in fabrics for vehicle interiors; in the manufacture of braids and ropes for various uses; in the manufacture of rugs; in industrial applications, for example for filters and the like.Brief description of the drawings

[0020] Further features and advantages of the present invention will be more apparent from the description of the following nonlimiting examples of embodiment, with reference to the accompanying figures, wherein: Fig. 1 schematically represents a plant for implementation of the method in accordance with the invention for manufacturing polymeric yarns, particularly polypropylene; Figs. 2, 3 and 4 are photographs showing by way of example yarns produced in accordance with the invention. Description of embodiments

[0021] The accompanying Fig. 1 schematically illustrates a plant 1 for manufacturing yarns made of polymeric material, particularly polypropylene (material that will be referred to hereinafter by way of example), which can be used for manufacturing polymeric yarns, particularly polypropylene yarns, in implementation of the method of the invention.

[0022] The plant 1 comprises a plurality of spinnerets 2, particularly at least two spinnerets, operating in parallel.

[0023] Each spinneret 2 is configured to receive polymeric material (polypropylene), for example fed in the form of granules, that is melted and extruded in a perforated plate 3 provided with a plurality of holes to form respective filaments 4.

[0024] The polymeric material is melted by extrusion and / or directly through administration of heat and then made to pass through the perforated plate 3 of the spinneret 2, from which the material exits in the form of filaments and solidifies while it is being pulled by a system of pulleys.

[0025] The holes of the spinneret 2 are calibrated so as to produce filaments 4 having a count (size expressed as ratio between weight and length, i.e., linear density) between 1 and 5 den.

[0026] The filaments 4 delivered from each spinneret 2 are spun together to form a multifilament semi-finished strand 5 having a count between 100 and 1500 den.

[0027] The semi-finished strands 5 are also subjected, preferably concurrently with the spinning step, to a stretching step, for example carried out by feeding the semi-finished strands 5 through pairs of cylinders 6 in series operating at different speeds (with slower feeding cylinders 6a followed by faster stretching cylinders 6b).

[0028] In the stretching step, the semi-finished strands 5 are provided with a toughness (defined as the load in grams required to break a strand having a thickness of one den) between 2 and 7 g / den.

[0029] At least two semi-finished strands 5, and particularly from two to six semi-finished strands 5, are then sent to an air-jet texturing device 10, located downstream of the cylinders 6, to be subjected to an air-jet texturing step, in which the semi-finished strands 5 are coupled to form a textured yarn 11.

[0030] In particular, at least one central core strand 5a and one or more effect strands 5b arranged laterally along the central core strand 5a pass through a nozzle 12 of the air-jet texturing device 10 and are subjected inside the nozzle 12 to a pressurized air jet 13.

[0031] Preferably, the air-jet texturing step is carried out by blowing compressed air at a pressure between 8 and 16 bar, injected laterally and with a certain inclination with respect to the common direction of feed of the core strands 5a and of the effect strands 5b.

[0032] The core strands 5a and the effect strands 5b can have a different count.

[0033] The core strands 5a are fed to the nozzle 12 after being wetted: particularly, the core strands 5a pass through a wetting station 14 located upstream of the nozzle 12 in which they soak up water before being fed to the nozzle 12 where the air jet is injected.

[0034] Advantageously, the core strands 5a and the effect strands 5b are fed to the air-jet texturing device 10 by overfeeding, i.e., they are fed to the air-jet texturing device 10 at a speed higher than the exit speed of the yarn 11 from the air-jet texturing device 10.

[0035] For example, the exit speed V1 of the yarn 11 from the air-jet texturing device 10 is between 80 and 500 m / min; the feed speed V2 of the core strands 5a to the air-jet texturing device 10 is between 1 and 30% higher than the exit speed V1; and the feed speed V3 of the effect strands 5b to the air-jet texturing device 10 is between 10 and 200% higher than the exit speed V1.

[0036] A textured yarn 11 made of polymeric material, particularly polypropylene, having properties of high softness and bulk is obtained.

[0037] The yarn 11 can then be optionally subjected to one or more finishing operations, such as a steaming step, or the like.

[0038] Examples of yarns obtained in accordance with the invention are shown in Figs. 2, 3 and 4, where the textured structure of the yarns, with the core strands surrounded by the effect strands, is particularly clearly visible.

[0039] The yarn obtained in accordance with the invention is suitable for various applications and can be used, for example: in the clothing sector (particularly for knitwear and fabrics); in clothing accessories (bags, shoes, belts, etc.); in furnishing fabrics (orthogonal, jacquard, knitted fabrics, etc.); in fabrics for vehicle interiors; in the manufacture of braids and ropes for various uses; in the manufacture of rugs; in industrial applications, for example for suction or filtration systems, etc.

[0040] Finally, it is clear that further modifications and variations can be made to the polymeric yarn and to the manufacturing method thereof described and illustrated herein without departing from the scope of protection of the present invention, as defined in the appended claims.

Claims

1. A method for manufacturing polymeric yarns, particularly polypropylene yarns, comprising the steps of: providing at least two spinnerets (2) operating in parallel and having respective pluralities of holes, and feeding each spinneret (2) with polymeric material that is melted and extruded to form a plurality of filaments (4) having a count between 1 and 5 den; spinning the filaments (4) delivered from each spinneret (2) to form respective multifilament semi-finished strands (5) having a count, optionally different from one another, between 100 and 1500 den; coupling and texturing by air jet at least two semi-finished strands (5), the semi-finished strands (5) passing through a nozzle (12) where the semi-finished strands (5) are subjected to a pressurized air jet (13) to form a textured yarn (11).

2. The method according to claim 1, wherein the polymeric material is polypropylene.

3. The method according to claim 1 or 2, wherein the semi-finished strands (5) subjected to the air-jet texturing step comprise at least one central core strand (5a) and one or more effect strands (5b) arranged laterally along the central core strand (5a).

4. The method according to claim 3, wherein the core strands (5a) pass through a wetting station (14) located upstream of the nozzle (12) and in which the core strands (5a) soak up water before being fed to the nozzle (12) where the air jet (13) is injected.

5. The method according to claim 3 or 4, wherein the core strands (5a) and the effect strands (5b) are fed to the air-jet texturing step by overfeeding, being fed at a speed higher than the exit speed of the yarn (11) obtained in the air-jet texturing step.

6. The method according to claim 5, wherein the yarn (11) exits the air-jet texturing step at an exit speed (V1) between 80 and 500 m / min; and the core strands (5a) are fed to the air-jet texturing step at a first feed speed (V2) that is between 1 and 30% higher than the exit speed (V1); and the effect strands (5b) are fed to the air-jet texturing step at a second feed rate (V3) that is between 10 and 200% higher than the exit speed (V1).

7. The method according to any one of the preceding claims, wherein two to six semi-finished strands (5) are subjected to the air-jet texturing step.

8. The method according to any one of the preceding claims, wherein the semi-finished strands (5) are also subjected, preferably concurrently with the spinning step, to a stretching step, in which the semi-finished strands (5) are provided with a toughness, defined as the load in grams required to break a strand having a thickness of one den, between 2 and 7 g / den.

9. The method according to any one of the preceding claims, wherein the air-jet texturing step is conducted by blowing compressed air at a pressure between 8 and 16 bar.

10. A polymeric yarn (11), particularly polypropylene yarn, comprising at least one central core strand (5a) and one or more effect strands (5b) arranged laterally along the central core strand (5a); wherein the core yarns (5a) and the effect yarns (5b) have a count, optionally different from one another, between 100 and 1500 den and are formed of respective pluralities of filaments (4) having a count between 1 and 5 den; and wherein the yarn is an air-jet textured yarn.

11. The yarn according to claim 10, wherein the polymeric material is polypropylene.

12. The yarn according to claim 10 or 11, wherein the core strands (5a) and the effect strands (5b) have a toughness, defined as the load in grams required to break a strand having a thickness of one den, between 2 and 7 g / den.

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