SE462108B - PREPARATION OF TORR-SIZED TISSUE PAPER, WHICH A DIFFERENT MASS IS USED - Google Patents

Description

462 108 10 15 20 25 30 35 2 Paper production according to the wet forming technique conventionally available so that the mass - possibly together with one or more other pulps - soaked in water in a so-called machines during formation of a stock that is processed in different ways, above all by grinding in a mill or refiner before the same via a headbox or the like spread on one forming wire (alternatively a cylinder or the like) on which a coherent path of interconnected is formed fibers as the water in the stock passes through viran. This path is then brought to pass one number of press rolls and a drying station in which the same is dried to form finished paper.

For many uses, the paper is required stained; something that happens either through so-called stock staining or alternatively by surface painting. Stock dyeing, which is the most common staining method, is done by that the dye in question is added to it at all times uncoloured pulp fibers containing stock in one step somewhere between the spread of the mass in the machine vessel and the formation on the wire, usually already in the machine vessel, and fixed to the fibers in a suitable manner. Surface coloring is done by applying a color solution to the formed the paper web when it has passed the drying station, e.g. in a this subsequent glue press. Common remedies for thrush consists of sodium salts of organic sulfonic acids (CnH2n + 1, SO2OH) and nouns respectively dyes made up of linear molecules that can form hydrogen bridges with the fiber surfaces. Such stock staining gives in practice good results with regard to the task to provide a homogeneous implementation at the lowest possible cost colored paper; although the method in question is limited to a single consistent color or hue of the paper. In comparison with stock staining is surface staining more expensive and more problematic. A serious inconvenience of the surface coloring method is also that it not infrequently gives a paper with different color strengths on different pages. 10 15 20 25 30 35 462 108 3 Recently, in addition to the above related, conventional wet forming technology has also been developed methods of dry forming paper. Dry format paper is made in principle by placing it in sheets or web form delivered (alternatively fluffy) mass demolished and comminuted and incorporated into an air stream which, like the stock, is caused to pass a formation wire on which a substantially evenly thick paper web is formed.

In this case, it is required - in contrast to the case with wet paper - an additive of special binders with the task of tying together the individual fibers to a coherent path. In the dry forming method, which is particularly suitable for the production of a fluffy tissue paper with a structure very similar textile, the dyeing of the paper offers one mastered problem. Thus, the staining has previously our- by spraying on a suitable paint solution on the preformed paper web; a technique that in practice results in poor staining, regular results in a more or less flammable paper whose both sides have different color strength. Such tissue paper poorly suited for the manufacture of, for example, vetter, idukar and the like) ie products on which the requirements for even and homogeneous dyeing are great.

Brief description of the inventive concept The present invention aims to achieve a manufacturing process by which the dry format tissue paper can be given a simple and high-quality color ning. This is achieved by means of a procedure as close as possible characterized in that dried paper is used as the pulp, chemical market pulp whose fibers are colored by means of a coloring agent, for example an azo dye, which carried the fibers while they are still present in a water suspension with a pulp concentration of up to 50% in the pulp mill, but before final drying in this.

By coloring the pulp in accordance with the invention 462 108 10 15 20 25 30 35 4 already in connection with its production is not won only that colored tissue paper can be produced by dry forming without any dyeing operation in the paper mill or machine, but also that the can be carried out using conventional stock dyeing technology, which provides a homogeneous and durable dyeing of the fiber. Another significant advantage of the invention is that it enables production of a dry-formed tissue paper with a mottled structure.

Thus, in accordance with a preferred embodiment of the invention the paper is composed of two or several pulps of which at least one is colored, while the other is uncolored or differently colored.

The production of the chemical market pulp used according to the invention can, for example, be carried out in the manner set out in the attached flow chart.

From the kettle and various washing steps (and after any bleaching) in a conventional fiber line is pumped a suspension of cellulose fibers and water (pulp concentrates about 1%) to a first mixer 1 in which a hardener is added so that the hardness of the water degree will amount to 5 ° dH. This addition is made to achieve improved addition of a dye such as is added to a subsequent mixer 2. In question dye can be an azo dye, for example of that kind which is commercially available under the trade name CARTASOL ROT, whereby the dye is dosed in a quantity of 5% by weight based on the amount of dry mass. After color the dosage, the dye should have a residence time of about five minutes in a reaction vessel 3. A fixative, for example a quaternary polyhydroxyalkylene polyamine which sold under the name CARTAFIX FF, dosed at 4 in order for the last color residues to be added to losan and also to achieve good color fastness. Final- the fiber suspension passes through a reaction vessel In which the fixing fibers are applied may stay for about one minute. The cellulose fibers 10 15 20 25 30 35 462 108 are now colored.

The defibration mills included in the dry forming facilities require with today's technology that the mass a debonding agent is introduced which reduces fiber the bonds when the cellulose is dried. Addition of a such a plasticizer called BEROCELL B-584 in an amount of 0.3% by weight takes place in the mixer 6. The colored and plasticizer treated cellulose can now via a reaction vessel 7 with a residence time of about one minute go to a dryer 8 for conventional dewatering, final drying and winding.

The above procedure can be applied regardless of the mass is bleached or unbleached. For unbleached pulp is used in a conventional manner advantageously a basic dye containing an amino group (-NH2), while for bleached pulp is used acidic dyes, such as sodium salts of organic sulfonic acids, or substantive dyes made up of linear molecules that can form hydrogen bridges with the fiber surfaces. In the latter case required no fixative. It is also conceivable that use different types of pigment dyes that are insoluble in water and precipitates on the fiber when glued with resin and alum.

It should also be noted that a cellulose according to above can also be produced without plasticizers, but then requires a significant increase in the capacity of the the ring mill in the dry forming plant. Although in question future dyes are most suitably applied to the fibers while these are still suspended in water in low concentrations, eg about 1%, it is in and for it is conceivable to take care of the paint application even at higher pulp concentrations¿ tlex all the way up to about 50% that can occur in press sections after the wire.

The important thing is that the color addition is carried out before the final drying.

Claims (2)

462 108 PATENT CLAIMS Process for the production of dry-formed tissue paper from pulp, in particular for the manufacture of cloths, napkins and the like, characterized in that dried pulp is used as pulp, chemical pulp whose fibers are dyed by a dye, e.g. azo dye, which is added to the fibers while they are still in an aqueous suspension with a pulp concentration of up to 50% in the pulp mill, but before final drying in this. 2. A method according to claim 1, characterized in that the paper is composed of two or more pulps of which at least one is colored, while the other is uncoloured or differently colored to provide a tissue paper with a mottled structure. f: