PROCESS OF MANUFACTURE FOR A COLOURED FIBRE MATERIAL, CONTAINING A CERTAIN PROPORTION OF CELLULOSE FIBRES, SUCH AS PAPER AND NONWOVEN, AND A COLOURED FIBRE MATERIAL MANUFACTURED ACCORDING TO THE PROCESS

Abstract: Process for the manufacture of a coloured fibre material, containing a certain proportion of cellulose fibres, such as paper and nonwoven. A dyestuff is applied onto reel or sheet pulp either on the whole material or only on part of it, whereupon the reel or sheet pulp is defibrated and dispersed in liquid or foam possibly together with other fibres. The fibre dispersion is thereafter applied onto a wire and dewatered, whereupon the formed fibre web, which contains a substantially even addition of coloured fibres, is subjected to possible further treatment steps before drying and reeling. A fibre material manufactured according to the process is also disclosed. If only part of the pulp fibres are coloured, a mottled colour impression of the material is obtained.

Description: PC-7SE95/01S49 Process of roflny.fflct_ure for a coloured fibre material . containing a certain proportion of cellulose fibres, such as paper and rioηwovep, and a coloured fibre material manufactured according to the process Technical area The present invention relates to a process of manufacture for a coloured fibre material, containing a certain proportion of cellulose fibres, such as paper or nonwoven, wherein a dyestuff is applied onto reel or sheet pulp either on the whole material or only on part of it. The invention further relates to a coloured fibre material manufactured according to the process. Background of the invention Nowadays paper is as a rule coloured with cationic direct dyes, which are water insoluble dyestuffs with strong affinity to cellulose fibres. The dyestuff is generally added to the fibre dispersion, i.e. the fiber dispersion in water which is applied onto the wire, but it can also be applied onto the completely formed paper sheet by means of various application methods. These colouring methods have in common that they give a dyeing of all pulp fibres containing reactive groups whereby a comparatively evenly coloured paper sheet is obtained. In manufacture of paper based on recycled fibres it occurs that coloured paper is reused and thereby a recycled paper pulp is obtained with an element of coloured fibres giving a paper with a mottled colour. SUBSTITUTE SHEET Coloured nonwoven materials can be manufactured i different ways, e.g. by addition of a certain proportion o coloured synthetic fibres. This is however comparativel expensive because of the high price involved with coloure fibres. A cheaper way of colouring nonwoven material is t apply dyestuff by means of some form of finishing treatmen such as Foulard treatment or by printing of dyestuf possibly together with a binder. Both Foulard treatment an printing make great demands on accurate dyestuff dosin systems if a result pleasing to the eye is to be obtained In certain types of soft tissue paper, e.g. napkins an nonwoven material , a mottled colouring may be preferabl because of aesthetic reasons, since a mottled colouring i associated with textile rather than paper. It is known from US-A-4,202,852 to manufacture a coloure drylaid nonwoven material by applying dyestuff onto reel o sheet pulp, which is thereafter dried to a moisture conten of less than 15 % and defibrated in a hammer mill. Th fibres are airlaid onto a wire, whereupon a binder is adde to the airlaid fibre web. After curing of the binder a evenly coloured drylaid fibre material is obtained. Object of the invention and most important features The object of the present invention is to achieve a simpl process for colouring of wetlaid or foamformed fibr materials, such as paper and nonwoven. The process shoul allow both a complete colouring of the material as well a a mottled colouring. According to the invention this ha been achieved by applying a dyestuff onto reel or shee pulp either on the whole material or only on part of it whereupon the reel or sheet pulp is dispersed in a liqui or foam possibly together with other fibres, and that th SUBSTITUTESHEET PC-7SE95/01549 fibre dispersion is applied onto a wire and dewatered, whereupon the formed fibre web, which contains a substantially even addition of coloured fibres, is subjected to possible further treatment steps before drying and reeling. Description of the invention Either all reel or sheet pulp is dyed or only part of it. In partial dyeing the dyestuff is suitably continously applied in a streak along the reel pulp, whereby the width of the streak determines how large a portion of the pulp is coloured and the dyestuff concentration determines the colour strength of the coloured pulp fibres. In partial dyeing between 1 and 50 % of the pulp fibres are suitably coloured. A multi-coloured material can also be obtained by applying several different colours in different streaks, which for example enables the manufacture of material which at a distance appears to be green but which in reality contains both yellow and green pulp fibres. The dyestuff used should have strong affinity to cellulose so as to fix it to the pulp fibres without spreading or bleeding out to the water or foam when defibrating the pulp. Conventional cationic direct dyes which are used for normal colouring of paper function exellently for this purpose. Also other dyestuffs bound to the pulp fibres with a binder may be used. The dyestuff is applied onto the reel or sheet pulp by spraying, coating, Foulard treatment or printing. Other fibres such as synthetic fibres, vegetable fibres, regenerated cellulosic fibres and/or pulp fibres, e.g. originating from bale pulp, may be mixed with the reel pulp fibres in the dispersing vessel. SUBSTITUTE SHEET The fibre dispersion is formed and thereafter applied o a wire for dewatering. After the dewatering, the colou fibre web may be subjected to possible further treatm before drying and reeling, e.g. creping for manufacture soft tissue paper, embossing, addition of various chemi additives such as softening agents, binders or wet stren agents. Before or after drying, the fibre web may a undergo hydroentanglement or other bonding technique manufacture of a nonwoven material. Fibre webs with different colour may also be lamina together into an unequal-sided coloured material. The invention will be described in the following in grea detail by way of several embodiments, which are however no means limiting for the invention. Example 1 In this trial a minor portion of the width of a continou running reel pulp web was coloured before it disintegrated and dispersed in a pulper containing fo i.e. a mixture of water, surfactant and air. The reel p was composed of bleached sulphate pulp (ECF) without addition of debonder. The basis weight of the pulp was g/m 2 and the web speed was 0.5 m/min. A conventional cationic paper dyestuff from Sandoz used, Cartasol Tύrkis KGL FL, diluted to 10 % dye solut calculated on the commodity. The dosing was performed w the aid of a membrane pump pumping dye solution to a noz located approx. 5 mm above the running pulp web which a web width of 254 mm. SUBSTITUTE SHEET At a flow of 11.25 ml/min dye solution a dye streak was obtained, on average corresponding to 12 % of the width of the pulp web and 0.3 weight-% calculated on the total pulp amount. Calculated on the 12 % of the pulp web which was dyed this means 2.5 weight-% dyestuff (commodity). After the dyeing, pulp was coarsely disintegrated and dispersed in foam in said pulper. Thereafter a papersheet consisting of approx. 88 % white pulp fibres and 12 % strongly coloured pulp fibers was foamformed. The foamforming was done according to the technique descriped in Swedish Patent Application 9402469-2. After pressing and heated air drying with conventional techniques, a paper sheet was obtained having an even, clearly mottled structure - turquoise pulp fibres against white background. Example 2 Also in this trial a minor portion of the web width, of a continously running reel pulp web, was dyed before dispersion in foam in a pulper as above. The reel pulp was composed of bleached sulphate pulp (ECF) without any addition of debonder. The basis weight was 750 g/πr and the web speed was 0.5 m/min. In this case another cationic paper dyestuff from Sandoz, Cartasol Blau KRL 80 % F, was used diluted to a 30 % dye solution calculated on the commodity. The dosing was done with the aid of a membrane pump pumping dye solution to a nozzle located approx. 5 mm above the running pulp web, which had a web width of 254 mm. SUBSTITUTE SHEET At a flow of 3.75 ml/min dye solution a dye streak w obtained, on average corresponding to 5 % of the total pu web width and 0.3 weight-% dyestuff calculated on the tot pulp amount. Calculated on the 5 % of the pulp which w dyed, this meant 6 weight-% dyestuff (commodity). After the dyeing, the pulp was coarsely disintegrated a dispersed in foam in said pulper. In this case, commercially available polypropylene fibre (1.7 dtex x mm), was also simultaneously added into the pulper. T mixing ratio between the fibres was 60 % pulp fibres and % polypropylene fibres. Calculated on the total amount fibres (pulp + polypropylene), 0.18 weight-% dyestuff w added. Thereafter, a paper sheet, consisting of approx. 57 % whi pulp fibres, approx. 3 % strongly coloured pulp fibres a 40 % polypropylene fibres, was foamformed. The foamformi was done according to techniques described in Swedi Patent Application 9402469-2. The foamformed sheet was subsequently hydroentangled wi conventional entanglement techniques with an energy inp corresponding to 600 kWh/ton, see for example Swedi Patent Application 9402470-0. After pressing and heated a drying, a hydroentangled nonwoven material was obtain with an even, weakly mottled structure - blue pulp fibr on white background. The invention is of course not limited to the abo described embodiments but may be varied within the scope the following claims. SUBSTITUTE SHEET

Claims: Claims 1. Process for the manufacture of coloured fibre material, containing a certain proportion of cellulose fibres, such as paper and nonwoven, whereby a dyestuff is applied onto reel or sheet pulp, either on the whole material or only on a portion thereof, c h a r a c t e r i z e d in that the reel or sheet pulp after the application of the dyestuff is dispersed in liquid or foam possibly together with other fibres, and in that the fibre dispersion is applied onto a wire and dewatered, whereupon the formed fibre web which contains a substantially even addition of coloured fibres, is subjected to possible further treatment steps before drying and reeling. 2. Process according to claim 1, c h a r a c t e r i z e d in that the dyestuff is applied onto the reel or sheet pulp in a streak, the width of which is smaller than the width of the reel or sheet pulp. 3. Process according to claim 2, c h a r a c t e r i z e d in that dyestuffs of different colours are applied onto the reel or sheet pulp in different streaks. 4. Process according to any one or any of the preceding claims, c h a r a c t e r i z e d in that the dyestuff is applied onto the reel or sheet pulp by means of spraying, coating. Foulard treatment or printing. 5. Process according to any one or any of the preced claims, c h a r a c t e r i z e d in that the dyest shows strong affinity to cellulose fibres, for example cationic direct dyestuff. 6. Process according to any one or any of claims 1-4, c h a r a c t e r i z e d in that the dyestuff is bound the fibres by means of a binder. 7. Process according to any one or any of the preced claims, c h a r a c t e r i z e d in that the reel sheet pulp after dyeing is mixed and dispersed toget with other fibres, such as synthetic fibres, vegeta fibres, regenerated cellulosic fibres and/or pulp fibr 8. Process according to any one or any of the preced claims, c h a r a c t e r i z e d in that the for fibre web is creped for the manufacture of a tissue pap 9. Process according to any one or any of claims 1-7, c h a r a c t e r i z e d in that the formed fibre web subjected to hydroentanglement before or after drying. 10. Process according to any one or any of the preced claims, c h a r a c t e r i z e d in that fibre w having different colour are laminated together into unequal-sided coloured material. 11. Process according to any one or any of the preced claims, c h a r a c t e r i z e d in that a binder, strength agent or the like is added to the fibre web means of spraying, impregnation, coating or the equivale - 1 9 12. A wetlaid or foamformed fibre material, containing a certain proportion of cellulose fibres, such as paper or nonwoven, c h a r a c t e r i z e d in that a portion of the pulp fibres are coloured with one or several dyestuffs which gives the fibre material a mottled impression. 13. Fibre material according to claim 12, c h a r a c t e r i z e d in that between 1 and 50 % of the pulp fibres are coloured. 14. Fibre material according to claim 12 or 13, c h a r a c t e r i z e d in that the material also contains manmade fibres and/or vegetable fibres mixed with the pulp fibres. 15. Fibre material according to any one or any of claims 12-14, c h a r a c t e r i z e d in that the material is hydroentangled.

Inventors: HOLM ULF, REINER LENNART, HOLM, ULF, REINER, LENNART
Applicants: EDET AB, HOLM ULF, REINER LENNART, HOLM, ULF, REINER, LENNART
Application year: 1995
Main classification: D21H23
IPC codes: A47K7, D21H21, D21H23