DE1517225A1 - Process for decolorizing waste from printed paper or similar printed material - Google Patents

Description

of the company: HU (JH STEYEHSOF & SONS LIMITED, a. ' British. Company of Sum ± aerstown ¥ orks, Riverside-Road, London, S-. ¥. 17, England

■ ·. ■■; ■ -. ■■ '■ __ concerning

"Process for decolorizing" waste of printed paper or similar printed material "

. The invention relates to methods of decolorizing from printed paper or similar 'material,' such as printed cardboard and is in particular, but not exclusively applicable to the decolorizing of paper waste, which are essential components mechanical pulp included. . ■ .. '.

In known waste paper — deinking processes the waste paper cooked together with caustic soda to the Saponify and / or emulsify the oil base of the dye, which enables the coloring parts to be exposed. schAvemias and can then be blown away. However, these methods have proven to be 'unsuitable' for decolorizing such waste paper, which is more than just contains a minor amount of mechanical pulp, what

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by = the influence of caustic soda on the wood fibers in the mechanical pulp, which gives the pulp a yellow "to" brown color and the extent dewatering of the pulp produced is reduced.

Other "known deinking processes are based on the treatment of the waste material with detergents and subsequent washing, the material being brought into a chamber and comminuted to pulp by means of a stirrer the air is pumped out of the chamber to allow access of the cleaning liquid to the particles of the material and to promote the dissociation of the carbon and color particles so that they subsequently can be more easily washed out of the pulp.

In some known processes, the detergents are used to remove the oil base of the "dye" and leave behind the charcoal particles or other coloring particles, which then swim freely in the pulp suspension. In other known methods, a electrophoretic charge on the pulp and the dye particles induced to cause mutual repulsion support financially. However, it has proven difficult to remove the carbon or paint particles from the pulp suspension.

The present invention therefore aims to provide a method for deinking waste paper such as waste newspapers or the like material which does not require the waste material to be treated under vacuum and which at the same time leads to a sufficiently clean pulp that can be transformed into usable paper or cardboard enables "

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- ^J - '' In the method according to the invention for decolorizing

printed waste material, such as paper, becomes the material! * . SL /

• processed into a pulp in a solution containing a caustic potash, -a detergent or detergents, a soil suspending agent and / or contains an organic solvent. The process is usually carried out at atmospheric pressure and room temperature.

It has been found that certain compounds Have the property of suspending dirt, which separated from the fibers by the action of the surfactant or detergent. In a washing process, these compounds prevent redeposition laser on the dirt, so that it can be rinsed with Water is removable. These connections are known as protective colloids or dirt slurry solutions. Her The basic effect is quite different from that of the Surfactants, which primarily by reducing the surface tension of the liquid in which they are solved work. Although protective colloids or dirt-suspending agents can also have the property of increasing the surface tension up to However, this is not to be diminished to a certain extent primarily necessary for their successful business, Examples of such compounds, many of which are water-soluble cellulose derivatives, are: sodium arboxymethyl- Cellulose, Hydroxyl-Xthyl-Cellulose, Methyl-Cellulose, Methyl ethyl cellulose, sodium cellulose sulphate, gelluronic acid, Starch ether, casein, gliadin and soy white, ITodium alginate, ITodium poly-polyacrylate, waaser-dispersibles Lecithin tuid polyvinyl alcohol.

-: Eb vmrde also found that the addition of a organic solvent to the pulp Chemicals contributes to the caked oil charcoal or par b bandage in epidemics of this magnitude to unlock them so that they twist like a real colloid. This allows the color to be more easily achieved Remove the washing process and reduce considerably or »

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in some cases completely avoids the use of dirt suspension agents in chemicals.

The solvents used can depending on the Type of color to be removed can be varied. For decolorizing newsprint or other printing press papers chlorinated hydrocarbons such as trichlorethylene or perchlorethylene have proven to be very effective proven.

Other solvents that have proven themselves with the papers mentioned are:

Chlorinated hydrocarbons, e.g. methylene chloride, aromatic hydrocarbons, e.g. benzene, aliphatic hydrocarbons, e.g. Heptane or

Petroleum ether,

Alcohols, e.g. butyl alcohol,

Ether, e.g. dipropyl ether,

Ketones, e.g. methyl ethyl ketone,

Esters, e.g., ethyl acetate.

Various mixtures of these solvents have been found to be effective for lithographically printed papers and for removing the coating colors from embossed ones Letter heads proved.

A method for carrying out the invention will now be described in detail by way of examples.

In a method for carrying out the invention, used newsprint is floated with a propeller-like agitator in water of 3 "/ <> consistency (liquor ratio: 3 parts by weight of paper to 100 parts by weight of water). The water contains 4? Sodium hydroxide, 1.5 Yo non-ionic detergents (ethylene oxide condensation product of alkyl phenol), 0.5 ^ anionic detergent (dodecyl benzene sodium sulphonate type), 1 ° ß>

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a dirt-suspending agent (Fat rium-Car "b oxymethyl cellulose) and 3 ft organic solvent (Irichlorethylene).

In a further process, in which newsprint is suspended in water of .3 ft consistency (! Liquor ratio: 3 parts by weight of paper to 100 parts by weight of water) using a propeller-like stirrer and the water is 4 ft of sodium hydroxide, 1.5 ft of nonionic detergent ( Ethylene oxide condensation product of the alkyl phenol), 0.5 ft of anionic detergents (dodecyl-benzene-sodium sulphonate) and 1 ft of a soil-removing agent (iTatriuxa-Garhoxyiiietliyl-Cellulose).

In another method of practicing the invention, the treated Lösiingsmittel 4 includes ft Hatriumhydroxyd, 1 ft non-ionic detergents (polyoxy ethylene lther of glyceryl Triricinoleat) vaiä. 0.9 ft of soil release agent (sodium arboxymethyl cellulose). Although this method of removal is very effective, it "results in the production of a pulp of lower brightness as a result of the easy discoloration of the paper fibers *

The percentages in each case in all three examples are based on the weight of the chemicals in relation to the weight of the air-dry paper.

In the above examples, potassium hydroxide or Ifatriuni or potassium carbonate, the sodium hydroxide substitute.

The paper and the aqueous dispersion of chemicals are stirred for a period of about 6 minutes, the water being about Ratini temperature. After this process, the finely comminuted paper pulp is allowed to pass through a vibrating screen of high frequency, which reduces the pulp to about. Concentrated 10 ft consistency and it

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allows the black liquid to pass through the drain. The pulp is then either diluted back to a consistency of 3% with a fresh suspension solution or with pure water and fed back to the vibrating screen. The pulp is then deemed pure and further concentrated to remove as much of the chemicals as possible.

Subject to the deinking process, the cleaned pulp can be converted into paper sheets in the normal way. Several additional advantages of this method have been found. For example, the black solvent, which has passed through the sieve is reused for a second soling process, without this having an adverse effect on the purity the washed pulp and sometimes for a third slurry.

Alternatively, the black solvent which has passed through the sieve can be filled with fresh slurrying solvent to an extent of about 15 ' and the abrasion process can be continued in this way for any period of time. Another advantage is that the regenerated pulp has practically the same crispness or degree of baldness as the pulp when the first shark is used to treat the paper. By crispness or degree of cavity is meant the extent to which water can be drawn out of the pulp, and the production of a pulp of high crispness is a very important goal in the production of paperboard. It was found that a pulp with a crispness of 25 ° Schopper Riegler could be produced from old newsprint.

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Claims (6)

Claims 1. Process for decolorizing printed waste material » I j such as paper, marked! that the material is suspended in a solution which a caustic alkali, detergent or detergents Contains solimut suspending agent and / or an organic solvent. 2. The method according to claim 1, characterized in that g e k e η η , dcJi it under atmospheric pressure and carried out at Rcumteinperstur wire .. 3. The method nc ch claim 1 or 2, characterized geke η η is characterized, is the Duji sclmiutzsuspendierende means any £ us the group of compounds consisting of sodium Garboxyiuethyl-ZelluloöG, HydiOxy-ethyl © »-cellulose, ldethyl- ^ ellulose iuetityl-iLtL "ien-Zelluloae, ii & trium-Zellulose-SulpliL.t, Oelluronic acid, t>t.'Jri: e-ether, caseins, G-lia-, din and soy proteins, iiutriuiä-Aljin-1, Sodium polyacrylate, consisting of lecithin and iolyvin ;, 1-alcohol. . 4. The method according to one or more of the preceding claims, characterized ge Ί: e u π ζ calibration net that the crji .- ice ie solvent irj - :: AEII: G .: .νus is the group, · the cus Uriclilor -Ätiiylen, i'erc ^ lor-jithj len, Liethylenechlorid, Benaol, heptane, JfetroleuLi-ivther, ^ utyl-alcohol, Dipropyl-A'tlier, lieth ,. lut "t: _u " l-iieton una. ^ thjl-Acetct consist. . 5 · Ye_r: iiroi. n: cJ; oineiL α he preceding claims, dadurc ': .. keu ii aei ο 1: r. β t, dtJi dta x -ulpematerial from the jjwsun ^ suiittel through: a vibrating sieve separated, _{washed by fresh Losun 0} medium or lesser and from the 909815/0850 BATH 4517225 ■■ '- ι Washing liquid is separated by a vibrating screen. 6. The method according to claim 5 »thereby marked ζ eiöh ti e t that the solvent separated from the pulp meter is i & l is reused, next part of fresh solvent was added. 7 · Method according to one or more of the preceding claims, characterized in 'dE.ß the Detergentium or anionic detergents Odei ¹ are non-anionic or both. BATH ORIGINAL 909815/0850