KR790000846B1 - Process for de-inking printed waste cellulosic fibrous material - Google Patents

Abstract

Printed waste paper was de-inked by pulping the wastes to solids content 4-6% and treatment with biodegradable and nontoxic alk. solution of 0.3-3% (base on paper), and soln. of 8-24 ethoxylated (per monool mole or diol mole) monools or diols, and optionally followed by acidification to pH 7-11.5 with SO2. The de-inked pulp was then washed.

Description

De-Ink Treatment of Printed Waste Cellulose Raw Materials

The present invention relates to an improved method for de-inking a printed waste cellulose raw material.

SUMMARY OF THE INVENTION An object of the present invention is to provide a treatment method for producing pulp by deinking a printed cellulose raw material into a machine for producing raw newsprint, magazines and books.

Although many methods and compositions are already known as a method of treating the ink on the printing paper, the most effective among them is the use of a nonionic surfactant.

Unfortunately, the most effective nonionic compounds are not decomposed by living organisms, so effluents from the manufacturing process are toxic to marine organisms such as fish, and their treatment is problematic. A very wide variety of nonionic agents are described in US Pat. No. 3,069,308 (inventor Lissant), which acts as a deinking agent. Described in the US patents are generally non-ionic oxyalkylated alcohols. Particularly found to be effective are lauryl (C ₁₂ ) alcohols, methoxytripropylene (C ₁₀ ) glycols, tridecyl (C ₁₃ ) alcohols, n-butyl (C ₄ ) alcohols, furfuryl (heterocycle) alcohols and polyvinyl (Polyol) ethoxylated and propoxylated derivatives of alcohols.

In general, the inventors have found that very few of the ethoxylated alcohols, such as those exemplified in the US patent specification, have a very good effect on ink removal and consequently have brightness and tough lipids. In addition, it was found that the special agent of the present invention is non-toxic to aquatic organisms and can be decomposed by living organisms, so that even if the process by-products are disposed of in rivers or rivers, they do not cause pollution problems.

The deinking agent used in the process of the present invention is an ethoxylated fatty mono-ol having 14-30 carbon atoms (particularly 14-18 is preferred) in the aliphatic chain, which is a compound that can be degraded by living organisms and is nontoxic to aquatic organisms. It is a di-ol and has 8-24 (especially 8-12 are preferable) ethyleneoxy units per mole of these mono or di-ols. In general, the excellent deinking agents of the present invention are ethoxylated aliphatic mono-ols having 14-15 carbon atoms in the aliphatic chain or ethoxylated aliphatic groups having di-ol groups at adjacent carbon atoms which are not terminal in 15-17 carbon chains. Di-ols, all of which are characterized by having 9-11 ethyleneoxy units per mole of mono or di-ol.

In the case of di-ols, one of these two hydroxy groups may have no ethyleneoxy units and only one may collect ethyleneoxy units or may be split at an appropriate ratio between the two hydroxy groups. In the present invention, it is intended to use each compound of mono-ol or di-ol as well as mixtures thereof. Those skilled in the art of making and using ethoxylated surfactants will recognize that there is a limit to the range of their chain lengths in the formation of the chains by repeating aliphatic or ethyleneoxy units in the manner in which they are produced. The properties of these compounds are then expressed as the average of the number of carbon atoms and the number of repeating units.

Compared to the aforementioned US Pat. No. 3,069,308, the ethoxylated mono-ols of the present invention have at least 14 carbons in the aliphatic chain, up to 13 carbons in the aforementioned US patents, and in the case of di-ols. In the US patent has a maximum of 10 carbon atoms in the present invention has at least 14 carbon atoms.

Therefore, those skilled in the art will be able to produce the deinking agent of the present invention according to known processes. In practice, for example, ethoxylated aliphatic mono-ols may contain C ₁₄ -C ₁₈ aliphatic alcohols and an appropriate amount of ethylene oxide in the presence of an alkaline catalyst (e.g. caustic soda) under appropriate temperature and pressure conditions (e.g. 3 atm) can be produced. Also in the case of di-ol, a process similar to the whole is used for ethoxylation. A more detailed record of this process can be found in AM Schwartz and JW Perry, "Surfactants," Volume 1 (1949) and "Surfactants and Cleaning Agents," Volume 2 (1958). ), (Intro Science Publishing, New York).

The description is omitted here because the description is cited from the literature. Deinking agents are used in practice in solution phases in water-soluble media. The solution temperature of the deinking agent can be used in various ways, for example, from room temperature, such as 4.44 ° -21.11 ° C (40 ° -70 ° F), to about 93.33 ° C (about 220 ° F).

The deink solution described here works best when the pH is alkali. Therefore, it is desired that the alkali be contained in the solution. Suitable alkali or alkaline earth metal hydroxides or salts may be used, but sodium hydroxide and potassium hydroxide, soda ash and other equivalents are more preferred. The pH of the deink solution may be between 7.0 and 11.5, or higher, but sufficient alkali may be added to maintain the minimum pH at about 7.1.

In preparing the deink solution, water is charged to the reactor or pulp maker and 0.3-3% of the deink agent is added to the weight of the paper. It is advisable to dissolve the deinking agent in water before adding waste or scrap paper. Printed paper, pieces, waste paper, etc. are put in the combination solution. The printed fibrous material may, if desired, be ground in a suitable manner prior to treatment. However, it is not necessary and may be added directly to the treatment solution without treatment such as crushing or decomposing small in size. One of the advantages of the present invention is that no expensive grinding or pulping technique is required before de-inking. Therefore, it is advisable to put waste products to be de-inked into the treatment solution in a natural dry state, for example, without absorption of water or spraying water, usually in the air. De-inking occurs when waste paper is first slurried or pulped by water, but the general consequence is that waste paper is worse than putting it in a solution in its natural dry state, i. It was confirmed. If the waste paper is previously wetted with water and subjected to the chemical treatment described above, it becomes more difficult to fix the ink to remove the ink from the cellulose fibers. The amount of paper debris and waste paper added to the treatment liquid should be adjusted accordingly. Usually the cellulosic material should be less than 10% by weight relative to the weight of the deink solution, and less than 6% is good, but can usually be 4.0-6%. The best results are obtained when the deink solution is on the order of 5-5.5% of the paper weight, and the value seems to be the most desirable. Waste paper is immersed in the treatment solution until practically defiber and ink.

After treatment, the defiberized raw material is placed in a suitable storage container and diluted with water so that the solid concentration is 0.5-1.5%, in particular 1%, of the solution weight. Following dilution, the pulp is separated from the solution, washed with water and concentrated in a known manner. The pulp is acidified to a pH of 4-6.5 (preferably 4.5-5.5), enriched and then made into a web form. This acidification process significantly increases the brightness of paper produced from recycled pulp and eliminates the need for bleaching of the pulp. The recycled product may be mixed with sulphate or sulfite or further added to produce a cellulosic material such as newsprint.

Example 1

The de-ink solution was dissolved in 20.6 g of ethoxylated C ₁₄ -C ₁₅ primary mono-ol containing about 9.6 moles of ethyleneoxy units per mole of mono-ol, and then adjusted to pH of about 10.5 with alkali and in a laboratory pulp maker. It is made by adding 8 g of alkali metal silicate at 32.22 ° C (90 ° F). 100 g of printed waste paper (New York Times) is added to a pulp maker and stirred for 20 minutes. The temperature is then raised to 37.77-38.88 ° C. (100-102 ° F.). The deinked pulp is then washed by spraying water in a sieve filter and pressurized with a small manual press to become a washed paper sheet.

A portion of 40 g of the washed pulp (3 g on dry weight) wet weight is mixed with 0.002 g of sulfurous acid gas and heated to 62.77 ° C. (145 ° F.) for 20 minutes to form a sheet by the same method.

Example 2

Instead of ethoxylated aliphatic mono-ols, ethoxylated C ₁₅ -with hydroxyl groups on either side of non-terminal adjacent carbon atoms of the same weight and containing on average 10 moles of ethyleneoxy units per mole of di-ol The operation of Example 1 is repeated with C ₁₇ aliphatic diols. The sheet is formed in the same manner with or without acidification with sulfurous acid gas.

Comparative Test A

Instead of ethoxylated C ₁₄ -C ₁₅ primary alcohols, the operation of Example 1 was repeated using the same weight of ethoxylated C ₁₁ primary mono-ols containing only 5 moles of ethyleneoxy units per mole of alcohol. do. Paper sheets are prepared in the same manner from deinked pulp with and without acidification of sulfurous acid gas.

[Comparison Exam B]

Example 1 operation using the same weight of ethoxylated C ₁₅ -C ₁₇ aliphatic di-ol containing only 5 moles of ethyleneoxy units per mole of di-ol instead of ethoxylated C ₁₄ -C ₁₅ primary mono-ol Repeat. Paper sheets are prepared in the same manner from deinked pulp with and without acidification of sulfurous acid gas.

The paper sheet produced in the comparative example and the above example was examined for residual ink spots, and the brightness was A. C. Hardy's technology press plate adopted by the American Newspaper Publishers Association Research Institute. Measurements are made with a green filter using an Elrepho colorimeter under standard conditions based on the Boston (1936) AC Hardy-Hand book of Colorimetry, Technology Press, Boston.

The results are summarized in the following table.

[table]

It was found that paper made from pulp deinked using the special reagents of Examples 1 and 2 had a substantially higher reflectivity (brightness) than that of the reagents of Comparative Tests A and B. In addition, the reagents of Comparative Test A show many spots on the paper, and their low reflectivity is unusable even if they are a problem. In the case of the reagent of Comparative Test B, the luminance before and after the treatment of sulfurous acid gas was lower than that of the reagents of Examples 1 and 2 of the present invention.

Example 3

To demonstrate that the invention can be applied to samples that have undergone other manufacturing processes, it is repeated using New Burnswick Home News of the same weight instead of the New York Times of Example 1. The pH at the end of pulp production is 10.1. Again, the green filter brightness of the effectively deinked pulp is recycled to a strong paper that is 57.5 before sulfur dioxide treatment and 63.9 after treatment.

The deink treatment reagents of Examples 1 and 2 were found to be biodegradable and non-hazardous to aquatic organisms at normal use concentrations as a result of tests of standard operating procedures.

If you use about 11-16 kg (25-35 lbs) of de-inking agent in large-scale operations, add an appropriate amount of other additives based on one ton of dry paper. The solution is placed in a wet pulp mill or combined in the mill. The waste print paper is added to the solution so that about 6% of the paper is slurried with 94% of water.

The pulp making process is continued until the ink is removed from the fibers. After a reasonable time, the mixture is placed in a reservoir with a suitable stirrer. If necessary, water is placed in a reservoir to reduce the solids content of the mixture. The mixture of reservoirs is then diluted until washed to the solids content mentioned above, washed with water and concentrated by well known methods. The pulp is concentrated in this way to about 5% solids or about 3-8% solids. Cocurrent or countercurrent flushing may be used alone or in combination. The resulting pulp is acidified to the pH indicated above by the addition of a suitable dilute acid solution such as alum, sulfuric acid, sulfurous acid gas and the like. The pulp obtained is finally concentrated to a web state. The recovery of concentration and washing prior to the acidification step is not strictly regulated and the recovery of such treatment will depend on the type of apparatus used. If desired, it may be acidified and then bleached using a suitable bleach. However, it is generally not necessary to wash after acidification treatment to bleach, rather it is better not to wash.

Although this example describes a batch, or more precisely, batch batch process, it will be appreciated that de-inking may be performed using a continuous process if one skilled in the art. . The water used in this process is preferably soft water and free of iron.

Claims (1)

As detailed herein, ethoxydegradable, nontoxic to aquatic organisms and having 14-30 carbon atoms in the aliphatic chain and 8-24 ethyleneoxy units per mole of mono-ol or di-ol described below After adding the silylated aliphatic mono-ol or di-ol to water and adding an alkaline substance to maintain the pH of the deinking solution at 7.0 to 11.5, and deinking the waste cellulose material printed on the deinking solution described above, A process for deinking a printed waste cellulose raw material, characterized in that the deinked pulp is washed.