WO2004011717A1 - Method of deinking - Google Patents

Method of deinking Download PDF

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Publication number
WO2004011717A1
WO2004011717A1 PCT/EP2003/008166 EP0308166W WO2004011717A1 WO 2004011717 A1 WO2004011717 A1 WO 2004011717A1 EP 0308166 W EP0308166 W EP 0308166W WO 2004011717 A1 WO2004011717 A1 WO 2004011717A1
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WO
WIPO (PCT)
Prior art keywords
group
siloxane
independently
paper
additive
Prior art date
Application number
PCT/EP2003/008166
Other languages
French (fr)
Other versions
WO2004011717A8 (en
Inventor
Bernhard Nellessen
Christina Northfleet
Original Assignee
Dow Corning Corporation
Nopco Paper Technology Holding As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to AU2003254593A priority Critical patent/AU2003254593B2/en
Priority to CA2493758A priority patent/CA2493758C/en
Priority to US10/521,795 priority patent/US20060102298A1/en
Priority to DK03771095T priority patent/DK1540075T3/en
Priority to EA200500058A priority patent/EA008834B1/en
Priority to EP03771095A priority patent/EP1540075B1/en
Application filed by Dow Corning Corporation, Nopco Paper Technology Holding As filed Critical Dow Corning Corporation
Priority to JP2004523792A priority patent/JP4478019B2/en
Priority to DE2003615477 priority patent/DE60315477T2/en
Publication of WO2004011717A1 publication Critical patent/WO2004011717A1/en
Priority to HR20050087A priority patent/HRP20050087B1/en
Priority to NO20050989A priority patent/NO334965B1/en
Publication of WO2004011717A8 publication Critical patent/WO2004011717A8/en

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/59—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02—Working-up waste paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02—Working-up waste paper
    • D21C5/025—De-inking
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/03—Non-macromolecular organic compounds
    • D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
    • D21H17/13—Silicon-containing compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/64—Paper recycling

Definitions

  • the present invention relates to a method of deinking printed wastepaper.
  • Growing awareness of environmental damage caused by deforestation has seen an increase in the recycling of wastepaper in recent years. It has been recognised that the ability to recycle wastepaper is commercially advantageous and has a significant impact on the conservation of virgin fibre resources.
  • technological advances in printing inks and print media present ever-growing challenges to recyclers.
  • Printing on paper is typically accomplished using one of two types of ink, namely, impact ink, which is physically pressed onto the paper, and non-impact ink, which is attracted to a charged image and is then transferred to the paper.
  • Impact inks are typically wet inks, for example letterpress inks, offset litho inks, photogravure inks and flexographic inks.
  • letterpress inks are generally composed of carbon black pigment in a mineral oil vehicle and are used in, for example, newspaper printing.
  • Offset litho inks tend to contain more pigment than letterpress inks and contain drying oils such as linseed or alkyl resins.
  • Flexographic inks are used in similar processes to letterpress inks but are water-based and contain emulsified ink in an alkali soluble binder. Such inks may easily be dislodged, but may form extremely fine particles that are difficult to capture and remove .
  • Non-impact inks e.g. toners
  • toners are generally dry, powdered inks and are used in laser printing, photocopying and facsimile machines and generally comprise thermoplastic resins and pigment .
  • the wastepaper is disintegrated (pulped) by mechanical agitation in an aqueous medium to separate the ink and impurities from the paper fibre and disintegrate the ink into particles of approximately 0.1 to 1000 ⁇ m.
  • a grey slurry is thus obtained in which the ink is present in a finely dispersed form.
  • the impurities for example, plastic, aluminium foil, stones, screws, staples, paper clips etc., are removed during a large number of screening steps. Whilst ink detachment of non-impact, e.g.
  • photocopy, paper can normally be achieved in neutral conditions, for other printed paper ink detachment is routinely accomplished at alkaline pH levels using alkali hydroxides, alkali silicates, oxidative-working bleaches and surfactants at temperatures between 30 and 50°C.
  • alkali hydroxides alkali silicates
  • oxidative-working bleaches oxidative-working bleaches and surfactants at temperatures between 30 and 50°C.
  • anionic and nonionic tensides are used as surfactants, for example, soaps, ethoxylated fatty alcohols and/or ethoxylated alkyl phenols (see, for example, EP 0013758) .
  • the ink particles are then removed from the fibre slurry by washing and/or flotation. Smaller ink particles are removed by washing, and larger ink particles and stickies
  • the alkaline conditions used in traditional deinking methods cause water-soluble and/or colloidal solids and finely dispersed solids to contaminate the process water, for example, fillers, fine fibres and stickies. If these contaminants are insufficiently removed during washing, they can be concentrated by subsequent washings and reintroduced to the paper fibre, causing a loss of brightness in the resultant paper. Effluent containing the aforementioned chemicals conventionally used in deinking methods is also environmentally undesirable.
  • the present invention seeks to provide a method of deinking wastepaper which can overcome disadvantages of conventional deinking methods.
  • a method of deinking printed paper comprising pulping the paper to form an aqueous slurry, adding a deinking additive to the paper, and removing detached ink by flotation, wherein the additive comprises an organo-modified siloxane comprising units of the formula:
  • each R 1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group; each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or a group -R 2 - (0C p H 2p ) q (0C r H 2r ) S -P n is an integer greater than 1; a and b are independently 0, 1, 2 or 3;
  • R 2 is an alkylene group or a direct bond
  • R 3 is a group as defined for R 1 or Z above
  • p and r are independently an integer from 1 to 6
  • q and s are independently 0 or an integer such that 1 ⁇ q + s > 400
  • each molecule of the organo-modified siloxane contains at least one group Z.
  • Z is preferably a group -R 2 - (OC p H 2p ) q (OC r H 2r ) S -R 3 , more preferably wherein p and/or r are independently 2, 3 or 4, i.e. a group comprising ethylene, propylene, and/or butylene oxide groups.
  • p and/or r are independently 2, 3 or 4, i.e. a group comprising ethylene, propylene, and/or butylene oxide groups.
  • q and s are each independently integers from 10 to 30, more preferably 15 to 25 (for example 18) .
  • p is 2
  • r is 3
  • q and s are both 18.
  • R 2 may be an alkylene group, for example having from 1 to 6 carbon atoms (i.e.
  • R 3 may be a group as defined hereinabove for R 1 or Z, and is preferably a hydrogen atom or a hydroxyl group.
  • Z may be an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, for example an alkyl group having from 1 to 6 carbon atoms, i.e. a substituted methyl, ethyl, propyl, butyl, pentyl or hexyl group.
  • Z is a group -R 2 - (OC p H 2p ) q (0C r H 2r ) S -R 3
  • R 3 is preferably a hydroxyl or alkanoyloxy group.
  • siloxane molecule Preferably, 2 to 20 mole percent of silicon atoms in the siloxane molecule are substituted by a group Z, more preferably 5 to 16 mole percent.
  • the siloxane preferably has a hydrophilic/lipophilic balance (HLB)in the range of 5.0 to 7.3.
  • HLB hydrophilic/lipophilic balance
  • the molecular weight of the siloxane is preferably in the range of 1,000 to 500,000, more preferably 10,000 to 100,000.
  • a particularly preferred siloxane for use in the present invention is a hydroxy-endcapped linear polydimethylsiloxane having an HLB of 5.9 to 6.3, in which 10 to 12 mole percent of silicon atoms are substituted by Z groups of the formula -R 2 - (OC p H 2p ) q (OC r H 2r ) S -R 3 , in which p is 2, r is 3 and q and s are both 18, R 2 is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and R 3 is a hydrogen atom or a hydroxyl, ester or ether group.
  • the additive used in the present invention may comprise further components, in addition to the organo-modified siloxane.
  • the additive may further ' comprise one or more components selected from a polydimethylsiloxane, an organic polyether, and a fatty acid.
  • Suitable organic polyethers include those of the formula R 4 - (OC p H 2p ) q (OC r H 2r ) S -R 5 in which R 4 and R 5 are selected from a hydrogen atom, hydroxyl, alkyl and alkoxy groups, and p, q, r and s are as defined hereinabove.
  • Suitable fatty acids include saturated and unsaturated monobasic aliphatic carboxylic acids, for example having from 8 to 22 carbon atoms, such as lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric, palmitolic, oleic, linoleic, linolenic, and arachidonic acids .
  • the additive may be in the form of an emulsion, for example the organo-modified siloxane may be a gum based self- emulsifying siloxane. In the method of the present invention, the additive may be added to the paper before, during or after pulping.
  • the amount of additive to be added to the paper is preferably within the range 0.1 to 1 wt% of the paper, more preferably 0.1 to 0.5 wt%.
  • the additive may, for example, be added to the paper neat, as an emulsion, or in solution, for example an aqueous solution.
  • the method of the present invention is preferably performed at substantially neutral pH, although the method may be performed under alkaline pH.
  • the pulping and ink removal steps of the present invention may be performed as is conventional, as will be familiar to a person skilled in the art and described hereinabove .
  • the paper may be pulped to form an aqueous slurry having a consistency of, for example, from 1 to 10% (for example, 1 to 5%) at a temperature of between 30 and 50°C, for example 35 to 45°C. Consistency is defined as wt% of pulp solids in the fibre suspension.
  • Ink removal may be performed in a suitable flotation cell (for example, a Denver Lab flotation cell) at a suitable temperature, for example between 30 and 50°C (e.g. 35 to 45°C) , and number of revolutions per minute, for example from 500 to 1000 rpm.
  • An additional advantage associated with the method of the present invention is that when used to treat flexographic printed waste, the process water is relatively clear, whereas with known deinking methods it is generally black. Moveover, the present method produces pulp of improved brightness.
  • Steps a) and b) above were repeated using the siloxane used in Example 1 (Siloxane 1) and the siloxanes defined in Table 4 (Siloxanes 2 to 8) on fresh and aged wastepaper.
  • Table 4 also contains viscosity data for each of the siloxanes.
  • the experiment was also carried out using the commercially available fatty acid based deinking preparation used in Example 1. The results are shown in Table 2 (fresh wastepaper) and Table 3 (aged wastepaper) below. Whiteness was evaluated according to DIN 53145 Part 1.
  • Example 1 were added as an aqueous solution. The pulp was floated for 8 minutes at 45°C in a Denver Lab Flotation Cell.
  • Steps a) and b) above were repeated using the siloxane used in Example 1 (Siloxane 1) and two of the siloxanes defined in Table 4 (Siloxanes 4 and 7) .
  • the experiment was also carried out using the commercially available fatty acid based deinking preparation used in Example 1. The results are shown in Table 5 below. Whiteness was evaluated according to DIN 53145 Part 1.
  • Steps a) and b) of Example 1 were repeated using the siloxane used in Example 1 (Siloxane 1) , but were performed on 100% flexographic paper. In addition, 0.10 wt% sodium hydroxide and 1.20 wt% sodium silicate were added to the slurry.

Abstract

A method of deinking printed paper comprises pulping the paper to form an aqueous slurry, adding a deinking additive to the paper, and removing detached ink by flotation, wherein the additive comprises an organo-modified siloxane comprising units of the formula: [R1aZbSiO(4-a-b)/2]n in which each R1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group; each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or a group -R2- (OCPH2P) q (OCrH2r) S-R3; n is an integer greater than 1; a and b are independently 0, 1, 2 or 3; R2 is an alkylene group or a direct bond; R3 is a group as defined for R1 or Z above; p and r are independently an integer from 1 to 6; q and s are independently 0 or an integer such that 1 ≤ q + s ≥ 400; and wherein each molecule of the organo-modified siloxane contains at least one group Z.

Description

METHOD OF DEINKING
The present invention relates to a method of deinking printed wastepaper. Growing awareness of environmental damage caused by deforestation has seen an increase in the recycling of wastepaper in recent years. It has been recognised that the ability to recycle wastepaper is commercially advantageous and has a significant impact on the conservation of virgin fibre resources. However, technological advances in printing inks and print media present ever-growing challenges to recyclers.
Printing on paper is typically accomplished using one of two types of ink, namely, impact ink, which is physically pressed onto the paper, and non-impact ink, which is attracted to a charged image and is then transferred to the paper. Impact inks are typically wet inks, for example letterpress inks, offset litho inks, photogravure inks and flexographic inks. For example, letterpress inks are generally composed of carbon black pigment in a mineral oil vehicle and are used in, for example, newspaper printing. Offset litho inks tend to contain more pigment than letterpress inks and contain drying oils such as linseed or alkyl resins. Flexographic inks are used in similar processes to letterpress inks but are water-based and contain emulsified ink in an alkali soluble binder. Such inks may easily be dislodged, but may form extremely fine particles that are difficult to capture and remove .
Non-impact inks, e.g. toners, are generally dry, powdered inks and are used in laser printing, photocopying and facsimile machines and generally comprise thermoplastic resins and pigment .
The deinking of paper bearing these two different types of ink requires different deinking procedures and conditions. Conventionally, deinking of paper bearing non-impact ink merely requires pulping with a surfactant in neutral conditions, whereas paper bearing impact ink requires different conditions, such as treatment with alkali, silicate and peroxide, as well as a surfactant.
In conventional deinking methods, the wastepaper is disintegrated (pulped) by mechanical agitation in an aqueous medium to separate the ink and impurities from the paper fibre and disintegrate the ink into particles of approximately 0.1 to 1000 μm. A grey slurry is thus obtained in which the ink is present in a finely dispersed form. The impurities, for example, plastic, aluminium foil, stones, screws, staples, paper clips etc., are removed during a large number of screening steps. Whilst ink detachment of non-impact, e.g. photocopy, paper can normally be achieved in neutral conditions, for other printed paper ink detachment is routinely accomplished at alkaline pH levels using alkali hydroxides, alkali silicates, oxidative-working bleaches and surfactants at temperatures between 30 and 50°C. Usually, anionic and nonionic tensides are used as surfactants, for example, soaps, ethoxylated fatty alcohols and/or ethoxylated alkyl phenols (see, for example, EP 0013758) .
The ink particles are then removed from the fibre slurry by washing and/or flotation. Smaller ink particles are removed by washing, and larger ink particles and stickies
(i.e. glue residues and adhesives) are removed by flotation.
During flotation, air bubbles are blown into the pulp. The dispersed ink particles become attached to the air bubbles, which carry the ink particles to the surface. The resultant foam is then skimmed from the surface. Subsequent steps involve heating the pulp to evenly distribute stubborn ink particles and screening the pulp to separate the damaged, short or weak fibres. The remaining clean pulp is then pressed between rollers into sheets and dried.
Thus, efficient deinking demands both successful separation of the ink from the paper fibre and removal of the dispersed ink from the fibre slurry.
However, there are a number of disadvantages associated with traditional deinking methods. For example, the incomplete removal of ink particles from the fibre slurry can cause the resulting paper to have a grey hue, spotting, and a low degree of brightness. Brightness and colour are important quality criteria for many paper uses.
In addition, the alkaline conditions used in traditional deinking methods cause water-soluble and/or colloidal solids and finely dispersed solids to contaminate the process water, for example, fillers, fine fibres and stickies. If these contaminants are insufficiently removed during washing, they can be concentrated by subsequent washings and reintroduced to the paper fibre, causing a loss of brightness in the resultant paper. Effluent containing the aforementioned chemicals conventionally used in deinking methods is also environmentally undesirable.
The present invention seeks to provide a method of deinking wastepaper which can overcome disadvantages of conventional deinking methods. According to the present invention there is provided a method of deinking printed paper, the method comprising pulping the paper to form an aqueous slurry, adding a deinking additive to the paper, and removing detached ink by flotation, wherein the additive comprises an organo-modified siloxane comprising units of the formula:
[R aZbSιO(4_a_b) 2] n in which each R1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group; each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or a group -R2- (0CpH2p) q (0CrH2r) S-P n is an integer greater than 1; a and b are independently 0, 1, 2 or 3;
R2 is an alkylene group or a direct bond; R3 is a group as defined for R1 or Z above; p and r are independently an integer from 1 to 6; q and s are independently 0 or an integer such that 1 < q + s > 400; and wherein each molecule of the organo-modified siloxane contains at least one group Z.
Z is preferably a group -R2- (OCpH2p) q (OCrH2r) S-R3, more preferably wherein p and/or r are independently 2, 3 or 4, i.e. a group comprising ethylene, propylene, and/or butylene oxide groups. Preferably, q and s are each independently integers from 10 to 30, more preferably 15 to 25 (for example 18) . In a particularly preferred group Z, p is 2, r is 3, and q and s are both 18. R2 may be an alkylene group, for example having from 1 to 6 carbon atoms (i.e. a methylene, ethylene, propylene, butylene, pentylene or hexylene group) , or a direct bond. R3 may be a group as defined hereinabove for R1 or Z, and is preferably a hydrogen atom or a hydroxyl group.
Additionally or alternatively, Z may be an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, for example an alkyl group having from 1 to 6 carbon atoms, i.e. a substituted methyl, ethyl, propyl, butyl, pentyl or hexyl group.
The siloxane may be linear or may comprise units in which a + b = 0 or 1, i.e. the siloxane may contain branching. When Z is a group -R2- (OCpH2p) q (0CrH2r) S-R3, R3 is preferably a hydroxyl or alkanoyloxy group.
Preferably, 2 to 20 mole percent of silicon atoms in the siloxane molecule are substituted by a group Z, more preferably 5 to 16 mole percent.
The siloxane preferably has a hydrophilic/lipophilic balance (HLB)in the range of 5.0 to 7.3.
The molecular weight of the siloxane is preferably in the range of 1,000 to 500,000, more preferably 10,000 to 100,000. A particularly preferred siloxane for use in the present invention is a hydroxy-endcapped linear polydimethylsiloxane having an HLB of 5.9 to 6.3, in which 10 to 12 mole percent of silicon atoms are substituted by Z groups of the formula -R2- (OCpH2p) q (OCrH2r) S-R3, in which p is 2, r is 3 and q and s are both 18, R2 is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and R3 is a hydrogen atom or a hydroxyl, ester or ether group.
The additive used in the present invention may comprise further components, in addition to the organo-modified siloxane. For example, the additive may further' comprise one or more components selected from a polydimethylsiloxane, an organic polyether, and a fatty acid. Suitable organic polyethers include those of the formula R4- (OCpH2p) q (OCrH2r) S-R5 in which R4 and R5 are selected from a hydrogen atom, hydroxyl, alkyl and alkoxy groups, and p, q, r and s are as defined hereinabove. Suitable fatty acids include saturated and unsaturated monobasic aliphatic carboxylic acids, for example having from 8 to 22 carbon atoms, such as lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric, palmitolic, oleic, linoleic, linolenic, and arachidonic acids . The additive may be in the form of an emulsion, for example the organo-modified siloxane may be a gum based self- emulsifying siloxane. In the method of the present invention, the additive may be added to the paper before, during or after pulping. The amount of additive to be added to the paper is preferably within the range 0.1 to 1 wt% of the paper, more preferably 0.1 to 0.5 wt%. The additive may, for example, be added to the paper neat, as an emulsion, or in solution, for example an aqueous solution.
The method of the present invention is preferably performed at substantially neutral pH, although the method may be performed under alkaline pH.
The pulping and ink removal steps of the present invention may be performed as is conventional, as will be familiar to a person skilled in the art and described hereinabove . For example, the paper may be pulped to form an aqueous slurry having a consistency of, for example, from 1 to 10% (for example, 1 to 5%) at a temperature of between 30 and 50°C, for example 35 to 45°C. Consistency is defined as wt% of pulp solids in the fibre suspension. Ink removal may be performed in a suitable flotation cell (for example, a Denver Lab flotation cell) at a suitable temperature, for example between 30 and 50°C (e.g. 35 to 45°C) , and number of revolutions per minute, for example from 500 to 1000 rpm. An additional advantage associated with the method of the present invention is that when used to treat flexographic printed waste, the process water is relatively clear, whereas with known deinking methods it is generally black. Moveover, the present method produces pulp of improved brightness.
Embodiments of the present invention will now be described in detail.
Example 1 a) Pulping
To an aqueous suspension of llOg of air-dry wastepaper (50% newspaper and 50% magazine paper) having a consistency of 4% were added 440g of industrial water at 45°C in a mixing vessel. The suspended paper was kneaded for 15 minutes at 45°C. b) Ink removal
Water having a hardness of 16°dH was added to the pulp obtained in a) above to achieve a consistency of 1%. To the pulp varying amounts of a hydroxyl endcapped polydimethylsiloxane having approximately 11 mole % silicon atom substitution by - (OC2H4) 18 (OC3H6) 18 side chains, an HLB of approximately 6.1 and a molecular weight of approximately 60,000 (referred to herein as Siloxane 1) was added as an aqueous solution. The pulp was floated for 8 minutes at 45°C in a Denver Lab Flotation Cell at 1000 rpm, after which the pulp was separated from the water, and formed into sheets between two filters of a sheet former with drying at 95°C for 10 minutes under vacuum.
By way of comparison, steps a) and b) above were repeated using a commercially available fatty acid based deinking preparation. The results are shown in Table 1 below. Whiteness was evaluated according to DIN 53145 Part 1.
Table 1
C
Figure imgf000009_0002
Figure imgf000009_0001
Example 2 a) Pulping
To an aqueous suspension of llOg of air-dry wastepaper
(10% newspaper and 90% magazine paper) having a consistency of 20% were added 440ml of industrial water at 45°C in a mixing vessel. The suspended paper was kneaded for 15 minutes at 45°C. b) Ink removal
Water was added to the pulp obtained in a) above to achieve a consistency of 1.09%. To the pulp varying amounts of a hydroxyl endcapped siloxane as defined in Table 4 below were added as an aqueous solution. The pulp was floated for
8 minutes at 45°C in a Denver Lab Flotation Cell.
Steps a) and b) above were repeated using the siloxane used in Example 1 (Siloxane 1) and the siloxanes defined in Table 4 (Siloxanes 2 to 8) on fresh and aged wastepaper. Table 4 also contains viscosity data for each of the siloxanes. By way of comparison, the experiment was also carried out using the commercially available fatty acid based deinking preparation used in Example 1. The results are shown in Table 2 (fresh wastepaper) and Table 3 (aged wastepaper) below. Whiteness was evaluated according to DIN 53145 Part 1.
Table 2
Figure imgf000011_0002
Figure imgf000011_0001
Table 3
Figure imgf000012_0002
Table 4
Figure imgf000012_0003
Figure imgf000012_0001
Example 3 a) Pulping
To an aqueous suspension of llOg of air-dry wastepaper (100% newspaper) having a consistency of 20% were added 400ml of industrial water at 45°C in a mixing vessel. The suspended paper was kneaded for 15 minutes at 45°C. b) Ink removal
Water was added to the pulp obtained in a) above to achieve a consistency of 1.09%. To the pulp varying amounts of a hydroxyl endcapped siloxane as defined in Table 4 and
Example 1 were added as an aqueous solution. The pulp was floated for 8 minutes at 45°C in a Denver Lab Flotation Cell.
Steps a) and b) above were repeated using the siloxane used in Example 1 (Siloxane 1) and two of the siloxanes defined in Table 4 (Siloxanes 4 and 7) . By way of comparison, the experiment was also carried out using the commercially available fatty acid based deinking preparation used in Example 1. The results are shown in Table 5 below. Whiteness was evaluated according to DIN 53145 Part 1.
Example 4
Steps a) and b) of Example 1 were repeated using the siloxane used in Example 1 (Siloxane 1) , but were performed on 100% flexographic paper. In addition, 0.10 wt% sodium hydroxide and 1.20 wt% sodium silicate were added to the slurry.
By way of comparison, the experiment was also carried out using the commercially available fatty acid based deinking preparation used in Example 1. The results are shown in Table 6 below. The appearance of the filtration water was also recorded. Whiteness was evaluated according to DIN 53145 Part 1. Table 5
Figure imgf000014_0002
Table 6
I
Figure imgf000014_0003
Figure imgf000014_0001

Claims

1. A method of deinking printed paper, the method comprising pulping the paper to form an aqueous slurry, adding a deinking additive to the paper, and removing detached ink by flotation, wherein the additive comprises an organo-modified siloxane comprising units of the formula:
[R aZbSiO(4_a_b) 2] n
in which each R1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group; each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or a group -R2- (OCpH2p)q(OCrH2r) S-R3; n is an integer greater than 1; a and b are independently 0, 1, 2 or 3; R2 is an alkylene group or a direct bond; R3 is a group as defined for R1 or Z above; p and r are independently an integer from 1 to 6; q and s are independently 0 or an integer such that 1 < q + s > 400; and wherein each molecule of the organo-modified siloxane contains at least one group Z.
2. A method according to claim 1 wherein Z is a group
-R2-(OC'pDHH22p) qα ((OOCCrrHH22rr)) ss--R3
3. A method according to claim 2 wherein p and/or r are independently 2, 3 or 4.
4. A method according to claim 2 or 3 wherein q and s are each independently integers from 10 to 30.
5. A method according to claim 4 wherein q and s are each independently 15 to 25.
6. A method according to any one of claims 2 to 5 wherein p is 2, r is 3, and q and s are both 18.
7. A method according to any preceding claim wherein R2 is a methylene, ethylene, propylene, butylene, pentylene or hexylene group.
8. A method according to any preceding claim wherein R3 is a hydrogen atom or a hydroxyl group.
9. A method according to any preceding claim wherein the siloxane is linear.
10. A method according to any preceding claim wherein the siloxane contains branching.
11. A method according to any preceding claim wherein Z is a group -R2- (OCpH2p) q(0CrH2r) S-R3, and R3 is a hydroxyl or alkanoyloxy group.
12. A method according to any preceding claim wherein 2 to 20 mole percent of silicon atoms in the siloxane molecule are substituted by a group Z.
13. A method according to claim 12 wherein 5 to 16 mole percent of silicon atoms in the siloxane molecule are substituted by a group Z.
14. A method according to any preceding claim wherein the siloxane has a hydrophilic/lipophilic balance (HLB)in the range of 5.0 to 7.3.
15. A method according to any preceding claim wherein the siloxane has a molecular weight in the range of 1,000 to 500,000.
16. A method according to claim 15 wherein the siloxane has a molecular weight in the range of 10,000 to 100,000.
17. A method according to any preceding claim wherein the siloxane is a hydroxy-endcapped linear polydimethylsiloxane having an HLB of 5.9 to 6.3, in which 10 to 12 mole percent of silicon atoms are substituted by Z groups of the formula -R2- (0CpH2p) q (OCrH2r) S-R3, in which p is 2, r is 3 and q and s are both 18, R2 is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and R3 is a hydrogen atom or a hydroxyl, ester or ether group.
18. A method according to any preceding claim wherein the additive further comprises one or more components selected from a polydimethylsiloxane, an organic polyether, and a fatty acid.
19. A method according to claim 18 wherein the additive further comprises an organic polyether of the formula R4-(OCpH2p)q(OCrH2r)s-R5 in which R4 and R5 are selected from a hydrogen atom, hydroxyl, alkyl and alkoxy groups, p and r are independently an integer from 1 to 6, and q and s are independently 0 or an integer such that 1 < q + s > 400.
20. A method according to claim 18 or 19 wherein the additive further comprises a fatty acid which is a saturated or unsaturated monobasic aliphatic carboxylic acid.
21. A method according to claim 20 wherein the carboxylic acid is selected from lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric, palmitolic, oleic, linoleic, linolenic, and arachidonic acids.
22. A method according to any preceding claim wherein the additive is an emulsion.
23. A method according to claim 22 wherein the additive is a gum based self-emulsifying siloxane.
24. A method according to any preceding claim wherein the additive is added to the paper in an amount within the range 0.1 to 1 wt% of the paper.
25. A method according to claim 24 wherein the additive is added to the paper in an amount within the range 0.1 to 0.5 wt% of the paper.
26. A method according to any preceding claim which is performed at substantially neutral pH.
27 . A method substantially as hereinbefore described.
PCT/EP2003/008166 2002-07-24 2003-07-22 Method of deinking WO2004011717A1 (en)

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CA2493758A CA2493758C (en) 2002-07-24 2003-07-22 Method of deinking
US10/521,795 US20060102298A1 (en) 2002-07-24 2003-07-22 Method of deinking
DK03771095T DK1540075T3 (en) 2002-07-24 2003-07-22 Procedure for deinking
EA200500058A EA008834B1 (en) 2002-07-24 2003-07-22 Method of deinking
EP03771095A EP1540075B1 (en) 2002-07-24 2003-07-22 Method of deinking
AU2003254593A AU2003254593B2 (en) 2002-07-24 2003-07-22 Method of deinking
JP2004523792A JP4478019B2 (en) 2002-07-24 2003-07-22 How to remove ink
DE2003615477 DE60315477T2 (en) 2002-07-24 2003-07-22 Method of decoloring printed paper
HR20050087A HRP20050087B1 (en) 2002-07-24 2005-01-26 Method of deinking
NO20050989A NO334965B1 (en) 2002-07-24 2005-02-23 Method of de-digestion

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NO334965B1 (en) 2014-08-11
CN100357518C (en) 2007-12-26
AU2003254593B2 (en) 2009-03-19
JP2006503990A (en) 2006-02-02
AU2003254593A1 (en) 2004-02-16
PL216211B1 (en) 2014-03-31
JP5117477B2 (en) 2013-01-16
DK1540075T3 (en) 2007-12-27
KR101029233B1 (en) 2011-04-18
WO2004011717A8 (en) 2005-03-31
JP4478019B2 (en) 2010-06-09
CA2493758C (en) 2011-09-20
CN1671920A (en) 2005-09-21
KR20050036959A (en) 2005-04-20
NO20050989L (en) 2005-02-23
DE60315477D1 (en) 2007-09-20
HRP20050087A2 (en) 2005-10-31
DE60315477T2 (en) 2007-11-29
GB0217197D0 (en) 2002-09-04
JP2010053504A (en) 2010-03-11
PL373198A1 (en) 2005-08-22
ES2290508T3 (en) 2008-02-16
HRP20050087B1 (en) 2008-06-30
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EP1540075B1 (en) 2007-08-08
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