WO1998012377A1

WO1998012377A1 - De-inking liquid composition and its use for de-inking paper

Info

Publication number: WO1998012377A1
Application number: PCT/FR1997/001642
Authority: WO
Inventors: Marie-Odile Lafon; Maryse Pennavaire
Original assignee: Rhodia Chimie
Priority date: 1996-09-23
Filing date: 1997-09-17
Publication date: 1998-03-26
Also published as: EP0927277A1; FR2753713B1; NO991389L; SK37599A3; EA199900321A1; FR2753713A1; AU4306297A; CZ96299A3; EA001855B1; HUP9903780A2; HUP9903780A3; NO991389D0; PL332236A1

Abstract

The invention concerns a liquid composition containing at least one first surfactant (A) and at least one second surfactant selected between (B) and (C). The non-ionic surfactant (A) is a fatty alcohol selected among the polyethoxylated or polypropoxylated fatty alcohols of the formula R1-O-[(CH2CH2O)x . (CH2-CH∫CH3⊃O)y]-H. The non-ionic surfactant (B) is a fatty alcohol selected among the polyethoxylated fatty alcohols of the general formula R2-O-(CH2CH2O)z-H. The non-ionic surfactant (C) is a fatty alcohol selected among the polyethoxylated fatty alcohols corresponding to the formula R3-O-(CH2CH2O)w-H. The composition can be used for de-inking paper.

Description

LIQUID DEINKING COMPOSITION AND ITS USE FOR DEINKING PAPER

The present invention relates to a liquid paper deinking composition, used in the regeneration of pulp from old printed papers from newspapers, magazines, photocopies and computer papers, and its preparation process and its use for deinking paper.

Mainly, the subject of the present invention is a liquid deinking composition as well as its use, suitable for deinking paper by flotation and / or washing, making it possible to obtain a regenerated pulp of high quality having a high whiteness index and a content residual in very low ink and ensuring a stable and reliable deinking process. The deinking operation is very important because it represents one of the fundamental steps for recycling old paper.

Many methods of deinking old paper are known. The recycling of waste paper has become a very important industry in which we wish to develop and perfect new deinking compositions and their processes using them which consume little energy and natural resources and have little impact on the environment, while providing high quality regenerated pulp.

The conventional and usual methods of deinking old paper to provide basic material for papermaking fall into two categories; the first is a deinking process by flotation and the second is a deinking process by washing.

These deinking processes essentially consist of two phases. The first consists in defibrating the old paper, an operation also called pulping, and the second in removing the ink by flotation or washing.

The first phase is carried out by bringing old paper into contact, with stirring, with water and a chemical system generally comprising a silicate, a basic agent, a soap or a surfactant and a bleaching agent, introduced separately. Once the papers have been defibrated, according to a first alternative, the pulp is diluted and transferred to a flotation cell where air is injected by the bottom of the tank. A foam then occurs which entrains the ink particles, either by overflow from the tank in which the pulp is located, or by suction. According to a second alternative, the pulp is diluted and washed in water, then separated from the ink particles dispersed in water by filtration or centrifugation, this step being repeated as much as necessary in order to obtain a pulp whose qualities are suitable for reuse. A third alternative is to combine the washing and flotation steps to separate the ink from the pulp.

The chemical systems used for deinking are generally selected according to the mode of separation of the pulp and the ink particles.

For separation procedures by washing, the chemical system must be almost non-foaming in operational conditions in order to limit any mechanical problem with the devices used. In addition, the ink particles to be extracted from the pulp must be fine and well dispersed in the presence of the chemical system to increase the efficiency of the separation of said particles and obtain a high quality pulp.

For flotation separation processes, the chemical system must have greater foaming properties than that of washing processes. In fact, the ink particles in this case adhere to the foam generated within the flotation cell, which thus allows their separation from the pulp. On the other hand, the ink particles must be able to agglomerate in order to form large aggregates, also facilitating and increasing their separation from the pulp and their elimination by air bubbles.

The Applicant has developed a new liquid paper deinking composition which can be used both in deinking processes by flotation, and in deking processes by flotation and washing.

The new liquid composition according to the invention provides a high quality regenerated pulp with a high whiteness index and a very low residual ink content, while ensuring high performance and reliability in the industrial process using said composition.

Other advantages and characteristics of the invention will appear more clearly on reading the description and the examples which follow. The new composition developed by the applicant comprises at least a first nonionic surfactant (A) and at least a second nonionic surfactant chosen from (B) and (C).

The nonionic surfactant (A) is composed of at least one polyoxyethoxylated and polyoxypropoxylated aliphatic fatty alcohol of the following general formula: R ₁ -O - [(CH ₂ CH ₂ O) _x ^• (CH ₂ -CH <CH ₃ ) O) y] -H. in which :

- R- | is an alkyl © radical comprising between 16 and 22 carbon atoms, - the average value of x is between 5 and 30,

- the average value of y is between 2 and 20;

The second nonionic surfactant (B) is composed of at least one polyoxyethoxylated aliphatic fatty alcohol of the following general formula: R2-O- (CH ₂ CH ₂ O) _z -H in which:

- R ₂ is a linear alkyl radical comprising between 10 and 16 carbon atoms,

- The average value z is chosen such that the weight proportion of oxyethylene units is between 55 and 75% relative to the weight of the surfactant (B). For example, when the radical R ₂ contains 14 carbon atoms, z is between 6 and 13.

The third type of nonionic surfactant (C) is composed of at least one polyoxyethoxylated aliphatic fatty alcohol corresponding to the following general formula:

R ₃ -O- (CH CH ₂ O) _w -H in which:

- R3 is a linear alkyl radical comprising between 10 and 22 carbon atoms,

- The average value of w is chosen such that the weight proportion of oxyethylene units is between 35 and 45% relative to the weight of the surfactant (C). In general, the average value of w is between 1 and 10. For example, when the radical R3 contains 13 carbon atoms, w is between 1 and 4. In general, the weight ratio surfactant (B) / surfactant (A) is between 0.02 and 1, and the weight ratio surfactant (B) / surfactant (A) is between 0.02 and 1.

These compositions are either prepared within the operational environment during the implementation of the industrial paper deinking process or, preferably, are prepared in advance.

In the case of preparation in advance, the compositions are stable over time and do not particularly require the presence of stability additives.

Other compounds can be added in the preparation of the compositions or when they are used in the deinking process. One can in particular add soda, sodium silicate and hydrogen peroxide.

Preferably, the nonionic surfactant (A) is a mixture of fatty alcohols, the radical R- | is a linear alkyl of 16 to 20 carbon atoms with 7 to 13 oxyethylene units and 3 to 10 oxypropylene units and more particularly with 11 oxyethylene units and 4 oxypropylene units. By way of example, fatty alcohols suitable as surfactant (A) are coconut fatty alcohol, tallow fatty alcohol, palmitic, myristic, laureic and oleic fatty alcohol. Surfactants of type (A) which can be used in connection with the present invention are available from different commercial sources. In particular, the RHODITEK® 1000 and RHODITEK® 1200 products, marketed by Rhône-Poulenc, give good results in agreement with the preparations according to the invention.

Preferably, the nonionic surfactant (B) is a mixture of fatty alcohols whose radical R2 is a linear alkyl of 12 to 16 carbon atoms with a weight proportion of oxyethylene units of between 55 and 65% relative to the weight surfactant (B). More particularly, the surfactant (B) contains 6 to 10 oxyethylene units. Surfactants of type (B) which can be used in connection with the present invention are available from different commercial sources. In particular, the Symperonic A7 product marketed by ICI gives good results in agreement with the preparations according to the invention.

Preferably, the nonionic surfactant (C) is a mixture of fatty alcohols whose radical R ₃ is a linear alkyl of 12 to 14 carbon atoms with a proportion by weight of oxyethylene units of between 38 and 42% relative to the weight of surfactant (C). More particularly, the surfactant (C) contains 2 to 4 oxyethylene units. Surfactants of type (C) which can be used in connection with the present invention are available from different commercial sources. In particular, the Symperonic A3 product marketed by ICI and the Rhodasurf LA 30 product marketed by Rhône-Poulenc give good results in agreement with the preparations according to the invention.

The liquid composition according to the invention can be packaged in different forms and allows its use in all types of industrial devices used for deinking inked old paper. Thus, the liquid composition is prepared in the form of a solution, emulsion or dispersion without any noticeable changes in its performance being noted. However, according to a variant of the invention, the liquid composition is in the form of an aqueous solution. In this case, the amount of water is between 0.05 and 30% by weight.

The percentage by weight of surfactants present in the liquid composition varies according to the types of surfactants and is generally between 70 and 100 relative to the total weight of the liquid composition.

The surfactants used in the context of the invention are prepared according to methods known to those skilled in the art. By way of example, the surfactants are prepared by spraying with ethylene oxide or successive sprays of ethylene oxide and of propylene oxide on the basic fatty alcohol; the reaction is carried out at a temperature of the order of 160 ° C. in the presence of basic catalysis.

The liquid compositions according to the invention can be used according to the methods of the prior art. However, the applicant has developed a particularly effective deinking process, comprising at least one flotation step.

The deinking process using the liquid composition according to the invention consumes little energy and natural resources; furthermore, it has little impact on the environment, while providing high quality regenerated pulp. This original process in which the liquid composition according to the invention is used has two phases.

The first phase is the pulping step where the inked papers are brought into contact with said composition and water in a pulper to transform the pulp papers. The second phase includes at least one flotation step where the pulp is diluted in water. In this step the pH is either unmodified or advantageously adjusted to basic pH. The basic pH is preferably between 8.5 and 9.

During the first phase, the usual additives not contained in the liquid composition are added, if necessary. In general, the composition according to the invention is advantageously used with a surfactant concentration of the order of 0.01% by weight in the medium of the first phase, although higher or lower concentrations are not excluded. The content of old inked papers to be treated represents 5 to 20% by weight, and more particularly between 10 and 15% by weight in the medium.

This contacting operation can be carried out at room temperature, but more particularly it is carried out at a temperature between 30 and 70 ° C. It takes place in any type of known pulping apparatus provided with stirring and defibration means.

Once the operation of impregnating the old paper with the mixture of the liquid composition and the optional additives, the pulp can be left to stand for 0.5 to 4 hours. In general, before the second phase comprising at least one flotation step, the pulp is diluted so as to obtain a concentration of the pulp in water of 1 to 3% by weight.

We then proceed to the second phase, called flotation. This is done by injecting air through the bottom of the tank. The foam that forms carries the ink particles and separates it from the pulp. The foam is drawn out of the tank by overflow or else by suction.

The pulp free of ink particles can then be used in the preparation of papers.

As a variant according to the invention, it is possible to add at least one surfactant (B) or (C) after the pulping and before the flotation phase.

The following non-limiting examples and tests illustrate the preparation and use of the compositions according to the invention. EXAMPLES

Example 1 illustrates the use of a deinking composition according to the prior art.

The other examples illustrate deinking preparations according to the invention.

These preparations are prepared within the medium in which the paper to be de-inked is found, with the exception of Example 5 where the Rhodasurf LA 30 product is introduced after the pulping step.

The effectiveness of the deinking treatment is carried out by measuring the ISO whiteness of a sheet of paper formed from the pulp resulting from the pulping and flotation treatments. This efficiency translates for the examples according to our invention by an increase in whiteness compared to that obtained with the preparations of the prior art.

The compositions of Examples 1 and 2 have the same amounts of components with the exception of the composition of Example 2 additionally containing the product Symperonic A7. The nature of the 50/50 mixture of old newspapers and old magazines is identical for Examples 1 and 2.

The compositions 3, 4 and 5 have the same amounts of components with the exception of the compositions of Examples 4 and 5 additionally containing the product Rhodasurf LA 30. The nature of the 50/50 mixture of old newspapers and old magazines is identical for the examples 2, 3 and 5.

Example 1

The first step corresponding to pulping is carried out in a 25 liter pulper fitted with a helical turbine and a 15 liter flotation cell (LAMORT equipment).

The following mixture is introduced into the pulper: 50/50 mixture of old newspapers and old magazines 1500 g soda (25%): 60 g hydrogen peroxide (30%): 50 g

Rhoditek 1000: 3.37 g sodium silicate (33.8%, R Si0 ₂ / Na ₂ 0 = 3.3) 111g water at 45 ° C: 10 liters

The water has a controlled hardness, namely: [Ca ²⁺ ] = 3.10 ^"3 mol / l and [Mg ²⁺ ] = 1.10 ~ ³ mol / l.

The pulping is carried out for 12 minutes with a propeller rotation speed of approximately 1500 rpm. The pulp is then left to stand for 30 minutes. The second step, corresponding to the flotation, is carried out in a 15-liter flotation cell.

The pulp previously obtained is diluted with water of controlled hardness as defined above, so as to obtain a solid suspension at 1.2% of solid matter which is brought to the temperature of 45 ° C. The flotation step is carried out at natural pH for 6 minutes by air injection.

The float suspension is then filtered through a form filler. The farm is then dried and its ISO whiteness (diffuse reflectance factor in blue), measured according to standard NF Q 03-039, is 59.7.

Example 2

Rhoditek 1000: 3.37 g

Symperonic A7 0.27 g sodium silicate (33.8%, Rm Siθ ₂ / Na ₂ o = 3.3) 111 g water at 45 ° C: 10 liters

The water has a controlled hardness, ie: [Ca ²⁺ ] = 3.10 ^"3 mol / l and [Mg ²⁺ ] = 1.10" ³ mol / l.

The pulping and flotation are carried out under the same conditions as above.

The float suspension is then filtered through a form filler. The form is then dried and its ISO whiteness (diffuse reflectance factor in blue), measured according to standard NF Q 03-039, is 60.4.

Example 3 The first step corresponding to pulping is carried out in a 25 liter pulper fitted with a helical turbine and a 15 liter flotation cell (LAMORT equipment).

Rhoditek 1000: 3.37 g

Symperonic A7 0.18 g sodium silicate (33.8%, Rm Siθ ₂ / Na ₂ θ = 3.3) 44.40 g water at 45 ° C: 10 liters

The water has a controlled hardness, ie: [Ca ²⁺ ] = 3.10 ^"3 mol / l and [Mg ²⁺ ] = 1.10 ^{" 3} mol / l.

The pulping and flotation are carried out under the same conditions as above.

The float suspension is then filtered through a form filler. The form is then dried and its ISO whiteness (diffuse reflectance factor in blue), measured according to standard NF Q 03-039, is 51.7.

Example 4

Rhoditek 1000: 3.37 g

Symperonic A7 0.18 g Rhodasurf LA 30 0.75 g sodium silicate (33.8%, Rm ao ₂ / Na ₂ o = 3.3) 44.40 g water at 45 ° C: 10 liters

The water has a controlled hardness, ie: [Ca ²⁺ ] = 3.10 ^"3 mol / l and [Mg ²⁺ ] = 1.10" ³ mol / l. The pulping and flotation are carried out under the same conditions as above.

The float suspension is then filtered through a form filler. The form is then dried and its ISO whiteness (diffuse reflectance factor in blue), measured according to standard NF Q 03-039, is 53.5.

Example 5

The following mixture is introduced into the pulper: 50/50 mixture of old newspapers and old magazines 1500 g soda (25%): 60 g hydrogen peroxide (30%): 50 g Rhoditek 1000: 3.37 g

Symperonic A7 0.18 g

Rhodasurf LA 30 0.75 g sodium silicate (33.8%, Rm Sio / Na ₂ o = 3.3) 44.40 g water at 45 ° C: 10 liters The water has a controlled hardness, ie:

[Ca ²⁺ ] = 3.10 ^"3 mol / l and [Mg ²⁺ ] = 1.10 ^'3 mol / l.

The pulping and flotation are carried out under the same conditions as above, with the exception of the product Rhodasurf LA 30 which is introduced after the pulping step. The float suspension is then filtered through a form filler. The form is then dried and its ISO whiteness (diffuse reflectance factor in blue), measured according to standard NF Q 03-039, is 53.6.

Claims

1. Liquid deinking composition comprising at least a first surfactant (A) and at least a second surfactant chosen from (B) and / or (C):

B the nonionic surfactant (A) being composed of at least one polyoxyethoxylated and polyoxypropoxylated aliphatic fatty alcohol of the following general formula:

R _r O - [(CH ₂ CH ₂ O) _x ^• (CH -CH (CH ₃ ) O) y] -H. in which: - R- _] is an alkyl radical comprising between 16 and 22 carbon atoms,

- the average value of x is between 5 and 30, and

- the average value of y is between 2 and 20;

m the nonionic surfactant (B) being composed of at least one polyoxyethoxylated aliphatic fatty alcohol of the following general formula: R ₂ -O- (CH ₂ CH ₂ O) _z -H in which:

- R is a linear alkyl radical comprising between 10 and 16 carbon atoms, and preferably between 12 and 16 carbon atoms,

the mean value z is chosen such that the weight proportion of oxyethylene units is between 55 and 75% relative to the weight of the surfactant (B), preferably z being between 6 and 10;

m the nonionic surfactant (C) being composed of at least one polyoxyethoxylated aliphatic fatty alcohol corresponding to the following general formula: R ₃ -O- (CH CH ₂ O) _w -H in which:

- R ₃ is a linear alkyl radical comprising between 10 and 22 carbon atoms, and preferably between 12 and 14 carbon atoms,

the mean value of w is chosen such that the proportion by weight of oxyethylene units is between 35 and 45% relative to the weight

^' of the surfactant (C), preferably w being between 2 and 4.

2. liquid deinking composition according to claim 1, characterized in that the liquid composition comprises at least one surfactant (A), at least one surfactant (B) and at least one surfactant (C).

3. liquid deinking composition according to claim 1 to 2, characterized in that the surfactant (B) / surfactant (A) weight ratio is between 0.02 and 1.

4. liquid deinking composition according to one of claims 1 to 3, characterized in that the surfactant (C) / surfactant (A) weight ratio is between 0.02 and 1.

5. liquid deinking composition according to one of claims 1 to 4, characterized in that the nonionic surfactant (A) is a mixture of fatty alcohol whose radical R-- is a linear alkyl of 16 to 20 atoms carbon with 11 oxyethylene units and 4 oxypropylene units.

6. Aqueous deinking solution of liquid composition according to one of the preceding claims, characterized in that it contains between 0.05 and 30% by weight of water relative to the total weight of the aqueous solution.

7. Use of a liquid composition according to one of claims 1 to 5 for deinking paper.

8. Use of an aqueous solution according to claim 7 for deinking paper.

9. Method for deinking old inked papers in the presence of a liquid composition according to one of claims 1 to 5 comprising two phases:

- The first phase consisting of a pulping step where the inked old papers are brought into contact with said composition and water in a pulper to transform the papers into pulp. the second phase comprising at least one flotation step where the pulp is diluted in water with pH not modified in the medium or with basic modified pH of between approximately 8.5 and 9.

10. A method of deinking old inked papers according to claim 9, characterized in that at least one surfactant (B) or (C) is added after the first phase and before the second phase.