IE42576B1 - A method of producing synthetic yarn simulating a natural yarn and a yarn manufactured therefrom - Google Patents

Abstract

1526442 Fibrillated film BELFAST ROPEWORK CO Ltd 29 April 1976 [3 May 1975] 18632/75 Heading B5B Yarn simulating a natural yarn is prepared by extruding a mix of a polymer, colouring agent and UV stabilizer, causing fibrillation of the extruded mix and twisting to form a yarn. A matting agent may also be present. The preferred polymer is polypropylene.

Description

This invention relates to a method of producing a synethetic yarn simulating a natural yarn and a yarn manufactured therefrom. Ropes, twine and the like are generally manufactured from natural fibrous material such as jute, hemp or cotton, manila rope and twine, sisal rope and twine and sisal baler twine, but the properties of such materials, for example strength, weight and workability, are inferior to those of many synthetic polymeric materials. It has previously been proposed to use synthetic polymeric materials for the manufacture of ropes, twine and the like, but an attendant disadvantage lies in the synthetic appearance of such products.

It is an object of this invention to provide a method of preparing a synthetic yarn which resembles a natural yarn in appearance and which will permit ropes, cordage, twine and the like to be manufactured therefrom.

According to the present invention there is provided a method of producing a synthetic yarn simulating a natural yarn, including forming a fluent mix containing a polymeric material suitable for yarn production, a colouring agent for colouring the mix the same color as the natural yarn being simulated, and a UV light stabilizer which acts to stabilize the colour of the colouring agent, extruding the fluent mix, causing fibrillation of the extruded mix, and twisting to form a yarn. - 3 Preferably the polymeric material is a polyolefin.

The colour agent may for example be in the form of granules, powder or paste prior to its inclusion in the mix, and it may be a material, such for example as a pigment, which colours the mix prior to extrusion so that the extruded mix is of a colour similar to that of a natural fibre. Alternatively the colouring agent may be in the form of a material which can react with another material to produce the desired colour. In this case the other material may be added to the extruded mix to produce the required colour.

The final colour of the yarn may further be controlled by varying the speed and/or temperature of extrusion.

Many polymeric materials are of coarse texture and if such materials are used in the present method it is preferable to soften the texture so as to resemble more closely the appearance and texture of natural fibre. The texture softening may for example be effected by mixing together the polymeric material and a softening agent such as low-density polyolefin, for example polyethylene, and heating the mix to form a melt. When the melt is subsequently cooled the polymeric material is found to have acquired a softer texture.

Texture-softening may alternatively be effected by selecting a polymer having a high melt flow index, by extruding the polymer material at a high melt temperature, using a chilled roller at a higher temperature than is common in the art, and by passing the polymeric material over a fibrillating roller having a large number of pins, or by applying a suitable substance to the surface of the material.

If the polymeric material used has a shine, or glossy appearance, it can be treated to produce a more matte finish and thereby resemble natural fibre more 435 7 6 closely. The matte finish may he achieved in several different way::, an for ι%ι«ιρ!ι· by (ormiiuj a mix comprisin') the polymeric material and a jnal.tiny nyonl. such as v, Inc sulphide, melting the mix to render it homogeneous and solidifying the melt. The colouring agent may have matting properties, so that the inclusion of a separate matting agent may he unnecessary. The matte finish may alternatively be produced by fibrillating the material.

Xn an experiment to compare the properties of natural hemp, cotton twine and simulated cotton twine prepared from synthetic yarn made by the method of the invention, the following results were obtained! Natural hemp Natural cotton Simulated cotton Denier 12,800 Metres/kg 703 Breaking strain (kg) 26 Tenacity (G/D) 2.0 ,280 444 0.99 13,060 689 6.2 The simulated cotton closely resembled the natural cotton both in texture and in appearance, and it can be seen from the above results that the simulated cotton was superior in strength, lightness of weight and general workability .

An embodiment of the present invention will now be described by way of illustration in the following Example.

Example Colouring agents in the form of iorn oxide (Brown GS pigment, colour index No. 77491), a disazo oompound (Yellow RS pigment, colour index No. yellow 83) and carbon black (Black CS pigment, colour index No. 77266) were mixed together with zinc sulphide and granulated polypropylene, in the following parts by weight: 43576 - 5 - Iron oxide 0.078 Disazo compound 0.045 Carbon black 0.033 Zinc sulphide 1.240 Polypropylene 8.604 The resulting mix was blended by heating to a temperature in the range from 205 to 250°C, cooled and granulated. The granulated blend was then mixed with an ultra-violet stabiliser in the form of UV 531 manufactured by Cyanamid International (2-hydroxy-4-n-octoxybenzophenone), low-density polyethylene, and granulated polypropylene in the following parts by weight: Blend 10 U-V Stabiliser 4 Low-density polyethylene 6 Polypropylene 80 The resulting mixture was melted, extruded and fibrillated under the following conditions: Barrel temperatures (°C) Die temperature Cooling Chilled roller and first godet speed Second godet speed Draw ratio Hot-air oven temperature Number of pins on fibrillation roller Pin roller speed 230, 240, 250, 260, 265 265°C By chilled roller lOm/min 120/min 12:1 160°C per inch 120 m/mln The fibres obtained were than twisted together to form, for example, a rope or twine. 3 5 7 6 The yarn of the present invention can alternatively be produced, by preparing, for example, a pin-fibrillated slit film tape, a crush-fibriHated slit film tape, a combembossed film or a roller-embossed film.

Depending on the desired characteristics of the yarn, the draw ratio is preferably selected from within the range from 9:1 to 14:1 to obtain greater or lesser tenacity and lesser or greater elongation respectively.

Claims (9)

1. CLAIMS; 1. A method of producing a synthetic yarn simulating a natural yarn, including forming a fluent mix containing a polymeric material suitable for yarn production, a colouring agent for colouring the mix the same colour as the natural yarn being simulated, and a UV light stabilizer which acts to stabilize the colour of the colouring agent, extruding the fluent mix, causing fibrillation of the extruded mix, and twisting to form a yarn.

2. A method as claimed in claim 1, wherein the polymeric material is a polyolefin.

3. A method as claimed in claim 1 or 2, wherein the colouring agent is formed from two components which react to produce the desired colour.

4. A method as claimed in claim 1, 2 or 3, wherein a matting agent for rendering a matte appearance to the yarn is included in the mix.

5. A method as claimed in claim 4, wherein the colour agent has matting properties and thereby serves as the matting agent.

6. A method as claimed in any preceding claim wherein when the polymeric material is of coarser texture than the natural yarn being simulated a substance which softens the texture of the polymeric material is included in the mix.

7. A method of producing a synthetic yarn simulating a natural yarn, substantially as hereinbefore described with reference to the Example.

8. A synthetic yarn whenever produced by the method claims in any of the preceding claims.

9. A synthetic yarn whenever produced by the method claimed in any of the preceding claims.