DE353024C - Procedure for removing ink and ink from printing paper - Google Patents

Description

Γ BiBLiOTiIEtK "

-, iMOUSTRFKLEHEIQENDOM.

ISSUED
ON MAY 17, 1922

CLASS 55 b GROUP 4

According to the invention, printing ink, paint, ink, etc. is to be removed from printing paper using the clay known under the name bentonite.
For the purpose of carrying out the invention, the desired amount of the comminuted printing paper to be cleaned, a little water, an amount of alkaline material such as sodium hydroxide, sodium carbonate, amine is carried in a hollander. ίο monia, borax or the like, which, as is known, is used to bind the printing ink

• to dissolve and thereby allow the removal of the blackness, along with a quantity of

• very finely ground bentonite. This clay must be ground so finely that it clears the gaps can penetrate between the matted fibers. Excellent results have been obtained by using about 135 kg bentonite, 90 kg sodium carbonate and 300001

ao water on the barrel of old printing paper as an initial charge for the Dutchman.
■ The proportions can fluctuate within wide limits without changing the result, only the time used fluctuates

as accordingly. The working speed is increased considerably by the bentonite. The process can be carried out at ordinary temperature, but can be ^{accelerated by heating the initial charge to no more than about 50 °} C. and then using cold water.

While the Dutchman is being loaded in this way, he works in the known manner to thoroughly stir all the components of the load. Once this is done, the Dutchman's washing drum is lowered into place and more washing water is added to one end of the Dutchman's and thoroughly mixed with the pulp by the Dutchman's roller to be discharged in a steady stream at the other end of the Dutchman's. In a practical implementation, this washing was about i ¹ /. Hours continued. While the water flows through the Hollander, the following process takes place in the Hollander: The alkaline substance brings the printing ink in the paper into a state in which at least the dark colored particles of the dye show a strong affinity for the bentonite particles that the colored particles have cling. The bentonite is so fine that it remains suspended in the water, i.e. does not settle, and that it emerges with the paint particles adhering to it through the paper pulp and the sieves of the washing drum and through the outlet channel, with the result that during continued operation of the Dutchman, the draining water gradually takes all the dye with it, until finally the previously impure pulp remains in a condition sufficiently white for practical purposes. The operation of the washing drum is then stopped. Sufficient acid or salt of acidic character is then added to neutralize any traces of alcaline left behind and lighten the color. Sizing agent is then added, if desired, and dye to achieve the desired

desired tones and possibly alum. After thorough mixing, the pulp is removed and converted into paper that is completely satisfactory as printing paper used printing paper is far superior to achievable paper.

Bentonite belongs to the kaolin group of hydrous aluminum silicates. An analysis of a characteristic sample shows, for example, the following result:

SiO ₂ about 63 percent

Al ₂ O ₃ - 20

Fe ₂ O ₃ - 3

MgO in changing proportions

CaO in changing proportions

Na ₂ O - 5

K ₂ Ö in changing conditions

SO ₃ in changing proportions

H ₂ O.: - 9 -

100 percent.

The effect of the bentonite with regard to the removal of the dissolved or lifted carbon pigment or other dye is apparently that of a protective colloid, which is an envelope the particles of soot or dye with colloid causes and removal by the fiber layers deposited on the surface of the washing drum are allowed through. Bentonite has over 70 percent colloidal substance, which is evident for its great success Influence is.

The bentonite has no chemical effect on the paper, so it does not destroy it and is therefore not harmful, as would be the case with chemical action.

Bentonite is a very fine-grained clay. You don't notice any and between your fingers very little graininess when grinded between the teeth. Shows in the microscope that it consists of extremely small, more or less rounded particles of very uniform Size and apparently of the same mineral nature.

When analyzing according to the Dutch method, which is described in "Principles of Agriculture" by Harry N. Wiley shows that more than 50 percent of a given amount of bentonite. a diameter of less than 0.0015 mm according to the local classification Has. It is this subtlety that enables the effect described, because it has the Clay belongs to the class of real colloids and its effects to the class of colloid effects brings.

Tests have shown that the bentonite is more than three times its weight or absorbs seven times its volume in water and twice as much glycerine as diatomaceous earth records.

Attempts have been made to achieve this result with other clays with a coarser structure such as bentonite perform, such as "fuller's earth", "kaolin" and "china clay", it turned out but there is always the difficulty that the greater part of these clays is not fine enough to be used in Floating in water makes its way through the matted pulp on the sieves of the washing drum to take and take the paint with you. Hence an unduly long time and an excessive expenditure of sound and money is required, while in the new process essentially all of the bentonite goes through the pulp and sieves with the wash water and so the cleaning effect with the least expenditure of time and the smallest amount of clay brings about.

Instead of bentonite or other naturally very fine clays, one could - albeit with increased costs - one with the well-known KoUoid mills, for example the Plauson Mill, refined clay ο. use.

Claims (2)

Patent Claims: 1. Method of removing ink and ink from printing paper, thereby characterized in that the crushed printing paper with finely ground bentonite in the presence of an alkali such as sodium carbonate is treated in a Dutchman with the addition of water. 2. The method according to claim 1, characterized in that an acid, an acidic salt or an acidic reaction salt such as aluminum sulfate is added, to neutralize any remaining alkali and lighten the color of the paper stock.