MAGNETISABLE MAN-MADE FIBRES

Abstract: A man-made fibre is made magnetisable by incorporating magnetisable material in the body of the fibre. In particular the magnetisable material is added as an aqueous dispersion to a viscose composition from which the fibers are to be spun.

Description: Magnetisable man-made fibres. This invention relates to man-made fibres. In particular, the present invention is concerned with the production of man-made fibres exhibiting performance characteristics additional to those characteristics conventionally associated with the textile properties of man-made fibres. In this specification the term man-made fibres means viscose, and modal fibres. One such polyaramide is known under the trade identification code as P84, this material being manufactured by Lenzing AG. It is particularly intended that textile material, for example, when in sheet form should when incorporating the fibres of the present invention endow the textile material with the aforesaid additional characteristics in such manner that the efficiency, performance or the like of the additional characteristic should not be destroyed or excessively degraded by the manufacturing or post manufacturing processes or treatment stages to which the fibres and textile sheet material are likely to be subjected in order to provide the requisite textile properties. For example, it has been proposed to render textile material magnetisable by bonding to the textile material foils which have been coated with magnetisable material. However, such known proposals have been found, in practice, not to lead to an acceptable product, since t e various treatments to "Which the textile material is conventionally subjected or may for specific reasons be subjected in order to achieve or enhance the requisite performance as a textile material, have resulted in a break-up of either or both of the bond and the foil thereby destroying the requisite magnetisability performance. It is an object of the present invention to 0 overcome these difficulties with the known attempts to render a textile material selectively magnetisable. Broadly, according to the present invention a magnetisable material is incorporated in the body of a man-made fibre. Conveniently the magnetisable material is introduced irito the melt or dope from -which the man-made fibre is drawn or spun. Preferably, the magnetisable material is added in the form of an aqueous dispersion to a viscose dope from 0 which the fibre is to be spun. Conveniently, the aqueous dispersion is produced by ball or bead milling magnetisable material or miss uEes of s ch materials for several hours. The magnetisable materials predominantly presently ξ used for magnetic recording include in addition to the main material Iron oxide in the ' form of f-F -Ct j , Chromium dioxide CrO« F magnetite Fe -0, '■ ■ Cobalt-containing V ^ -Iron Oxide, Cobalt containing ferrites and ferrous metal. As the coercivity of magnetisable materials used can be controlled by altering the physical shape of the particles of the magentisable material. Most magetisable material products presently in use are needle shaped with an aspect ratio range of 6:1 to 12:1. In spite of the extensive use of magnetisable materials in particulate form it has been surprisingly found that needle-shaped particles can not be used for incorporation into a man-made fibre such as viscose fibre since it has been found that the needle-shaped materials tend to form agglomerates in viscose and cause spinneret clogging. Therefore, according to a further aspect of the invention magnetisable particles having a non-needle-shaped form are incorporated into viscose fibres. Preferably, the magnetisable particles have a generally spherical shape. For a better understanding of the invention and to show how it may be carried into effect reference will now be made to the following Examples of the composition of solutions from which man-made fibres exhibiting magnetisable properties may be spun. EXAMPLE I Tn this Example, predetermined amounts f type' . - * (Bayferrox R8010 manufactured by Bayer) with a particle length of 0,7 microns, aspect ratio of 6:1 and a dispersing agent of the polyphosphate type (Geissfix C-30 manufactured by Zschimmer & Schwarz) were bead milled together with softened water to provide, after milling for a period of three hours, a magnetisable material Dispersion (A) having the following composition 20% Bayferrox 8010 0 4% Giessfix C-30 76% Softened Water The Dispersion (A) was mixed with a fibre forming viscose composition (B) containing 8,65% Cellulose and 5.2% Alkali in such proportion that the magnestisable material formed an amount equal to 25% of the amount cf cellulose included in the viscose Composition (B). The resulting mixture was introduced into a spinning bath comprising 8% H SO, , 26% Na Λ SO x and 1.5% ZnSO_ using a 2 2 4 4 spinneret with 800 orifices having a diameter of 80 ø microns to produce a denier of 3,3 dtex. After 30 minutes of spinning the pressure before the spinneret rose to 10 bars due to spinneret clogging and spinning'had' to he stopped. Even prolonged Jbead milling of the dispersion (A) could not yeild with the - c viscose composition (B) a resultant mixture which could be successfully spun. EXAMPLE II In this Example, using a magnetisable material of the magnetite type and comprising particles of a generally spherical form (Bayferrox 8600 manufactured by Bayer) a Dispersion (A1 ) was produced, by bead milling for three hours the following composition: 20% Bayferrox 8010 4% Giessfix C-30 76% Softened Water This Dispersion (A1 ) was mixed with the viscose composition (B) of the composition of Example I in such proportion that the magnetisable material formed an amount equal to 25% of the amount of cellulose included in the viscose composition (B). The resulting mixture was introduced into a spinning bath with the same composition as in Example I using the same spinneret as was used in relation to Example I. Spinning performed well without any pressure developing before the spinneret. The spinneret was examined after the spinning operation and no clogging of the spinneret could be detected. The fibres produced by the spinning process were subjected to conventional textile related process-operations, cutting and final processing to provide the following textile related data: Titre (dtex) 3.3 Fibre Strength cond {cN/tex) 20.0. Stretch (in %) 17.0 It was found on testing the thus produced fibres that the fibres demonstrated magnetisable properties. EXAMPLE III In this Example, the Dispersion (A ) of Example II was mixed with viscose composition .(J3) ,having the composition of Example I in such proportions that the magnetisable material formed an amount equal to 66.7% of the amount of cellulose included in the viscose composition (B) . It was found that the spinning operation performed well without any clogging of the spinneret. The fibres produced by the spinning process were subjected to conventional textile related process-operations, cutting and final processing to provide the following textile related data: Titre (dtex) 3.3 Fibre Strength cond (cN/tex) 15.0 Stretch (in .%) ...-_._0 It was found on testing the thus produced fibres _hat the fibres "demonstrated magnetisable properties. In general, the amount of the magnetisable material introduced into the viscose dope lies between 10% to 100% relative to the amount of cellulose in the viscose composition. In practice, a preferred range lies between 20% to 75%, below this concentration, the magnetic effect can possibly be considered to be too low, whilst above this concentration the it can be considered that the mechanical properties of the fibre are possibly unsatisfactory for some applications of the fibres. Whilst the specification has referred to a mixture of magnetisable material of the magnetite type other magnestisable materials may be used provided that they exhibit at least a similar magnetic performance and a non-linear shape when in particulate form i.e., materials that are spherical shape in particulate form so that dispersions of them when mixed with viscose are not prone to agglomeration. Practical tests have shown that the incorporation °f magnetisable materials into man-made fibres in accordance with the invention makes it possible magetically to record data/ inforamtion onto yarns incorporating the magnetisable fibres of the present invention and to subsequently detect/read-out the recorded data/information.

Claims: CLAIMS 1. A method of producing a man-made fibre exhibiting magnetisable properties, characterised in that magnetisable material is incorporated in the body of the _ fibre. 2. A method of producing a magnetisable man-made fibre as claimed in claim 1 , and characterised by incorporating the magnetisablematerial.into • - the ibre by introducing the magnetisable material into the dope 10 or the like from which the man-made fibre is drawn or spun. 3. A method as claimed in claim 2, and characterised by adding the magnetisable material when in the form of an aqueous dispersion (A1) to a viscose.composition .(B) T5 from which the- fibre is to " be spun. 4. A method as claimed in claim 3, and characterised by producing the aqueous dispersion (A1 ) by ball or bead milling magnetisable material or materials for several , hours in softened water. 20 5. A method as claimed in claim 3 or 4, and characterised in that when the magnetisable material is in .particulate form the particles have a. iran-liπear shape. -9- 6. A method as claimed in claim 3,4 or 5, and characterised in that when the magnetisable material is in particulare form the particles have a generally spherical-like shape. 5 7. A method as claimed in claim 6, and characterised in that the aqueous Dispersion (A) is mixed with a fibre forming viscose composition (B) within the range 10% to 100% of magnetisable material related to the cellulose content in the viscose (B). 10 8. A man-made fibre characterised in that magnetisable material is incorporated in the body of the fibre. 9. A man-made fibre as claimed in claim 8, and characterised in that the particles of the magnetisable -_ material comprises have a non-linear shape. 10. A man-made fibre as claimed in claim 9, and characterised in that the particles have a generally spherical shape.

Inventors: FIRGO HEINRICH, LEESTEMAKER HARM WILLEM, MARINI INGO, RUF HARTMUT, FIRGO, HEINRICH, LEESTEMAKER, HARM, WILLEM, MARINI, INGO, RUF, HARTMUT
Applicants: CHEMIEFASER LENZING AG, RUSSELL RAYNER ALBERT PATRICK, LENZING AG, RUSSELL-RAYNER, ALBERT, PATRICK
Application year: 1987
Main classification: D01F1
IPC codes: B23Q41, D01F1, D01F2, G06K1, G07C3, G11B5, H01F1