Classifications

• • 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
  • D21C5/027—Chemicals therefor
• • 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 the treatment of waste paper to remove ink from the paper. More specifically, the present invention relates to novel surfactant compositions useful in the removal of ink from waste paper, and to the use of such novel surfactant compositions in the removal of ink from the paper. The growing interest in recycling of used
• waste paper as a source in the manufacture of new paper and paper products has increased the demand for effective products and processes which are adaptable to the processing of the many different types of paper currently used in commerce.
• processes and reagents which are useful in the removal of ink from the waste paper.
• such reagents should be able to maximize removal of ink from types of paper currently known in commerce including newsprint, impact printed paper and non-impact printed paper.
• U.S. Patent No. 4,311,552 discloses deinking waste material, such as waste newsprint, in a slurrying process using a deinking agent which comprises a C 14 to C 20 alpha olefin sulfonate, particularly in combination with a nonionic detergent such as a 9-mole phenyl ethoxylate.
• U.S. Patent No. 4,935,096 discloses deinking of waste paper, using as the deinking agent an ionic surfactant, alone or in combination with nonionic surfactants.
• ionic surfactants are anionic compounds derived from alkylbenzene or hydrocarbons, such as sodium alkylbenzene sulfonates, sodium alcohol ether sulfates, sodium alcohol sulfates, and sodium alkyl or dialkyl sulfosuccinates.
• the disclosed cationic surfactants are mono, di or tri alkyl quaternary ammonium compounds .
• U.S. Patent No. 4,964,949 discloses deinking of waste paper employing a deinking agent which comprises a reaction product of one or more alkylene oxides with natural oils or fats and polyhydric alcohols, and also comprises a compound selected from the group consisting of alkylene oxide adducts of C 12 to C 18 alcohols, or sulfates of alkylene oxide adducts of C j to C l ⁇ alcohols, or C 8 to C 22 fatty acids or salts thereof.
• a deinking agent which comprises a reaction product of one or more alkylene oxides with natural oils or fats and polyhydric alcohols, and also comprises a compound selected from the group consisting of alkylene oxide adducts of C 12 to C 18 alcohols, or sulfates of alkylene oxide adducts of C j to C l ⁇ alcohols, or C 8 to C 22 fatty acids or salts thereof.
• Patent No. 5,158,697 discloses deinking of waste paper wherein the deinking agent comprises one or more of alkoxylated dimer acids and polymer acids of unsaturated fatty acids containing 16 to 20 carbon atoms; alkoxylates of partial esters of dimer acids and polymer acids of unsaturated fatty acids containing 16 to 20 carbon atoms esterified with alcohol containing 1 to 18 carbon atoms; or alkoxylated dicarboxylic acids or dicarboxylic acid monoesters of the following formula
• one of the X groups is COOH and the other is H or CH 3 , Y is H. or R, and R is an alkyl group containing 1 to 18 carbon atoms.
• the present invention is directed to a deinking composition useful in the froth flotation deinking of waste paper, comprising a surfactant mixture selected from the group consisting of (A) mixtures of (A.l) an anionic surfactant component selected from the group consisting of alpha-olefin sulfonates containing 8 to 22 carbon atoms, alkyl ether sulfates of the formula R'O- (CH 2 CH0) friendshipSOjNa wherein n is 1 to 4, R 1 is c C 8 -C ] ⁇ alkyl, and mixtures thereof; and
• R 2 is H or CH, j is 1-11, k is 1-11 and (j + k) is 10-14, the dialkoxylate containing a total of up to 0 60 propoxy and ethoxy units in a propoxy:ethoxy mole ratio of 0.2:1 to 4.0:1; and
• the present invention is also directed to a process of deinking waste paper, by subjecting the waste paper to froth flotation in a liquid composition comprising a surfactant mixture selected from the group consisting of (A) mixtures of
• waste paper is slurried and subjected to froth flotation in a liquid medium comprising any of the foregoing mixtures of surfactants, whereby ink and the waste paper are separated in the liquid medium, and then separating the slurried waste paper from the liquid medium containing the solubilized ink.
• the compositions of the present invention are particularly useful in removal of ink from waste paper and more particularly from waste paper comprising mixtures comprising two or more distinct types of paper, whether the paper has been imprinted by conventional impact-printing techniques with any of the inks used in that type of printing, or by non-impact printing techniques (such as laser printing) using any of the types of inks used in that kind of printing.
• an anionic surfactant component which is an alpha-olefin sulfonate, alkyl ether sulfate, or a mixture thereof.
• alpha ⁇ olefin sulfonates are meant sulfonates of straight and branched alkenyl groups containing 8 to 22 carbon atoms and containing at least one carbon-carbon double bond, as well as the hydroxylated counterparts thereof, including but not limited to compounds exhibiting either of the following formulas (A. I.a) and (A.l.b) , or mixtures thereof,
• R a is a straight or branched alkyl group, preferably straight, selected so that the molecule as a whole contains 8 to 20 carbon atoms.
• anionic surfactants include alpha-olefin sulfonates containing 14 to 16 carbon atoms in the molecule. 1
• alkyl ether sulfate is meant compounds of the formula (A.l.c)
• n 1 to 4
• R is C 8 -C ⁇ e alkyl
• Anionic surfactants of the foregoing formulas are commercially available and can readily be synthesized using known industrial chemical techniques.
• Preferred commercial examples include "Witconate AOS”, a c i ⁇ c i 6 alpha-olefin sulfonate, and "Witcolate ES-3", a sodium lauryl ether sulfate corresponding to the foregoing formula (A.l.c) wherein n is 3 and R 1 is C,_,-C j , alkyl, both of which are sold by Witco Corp.
• anionic surfactants have been found to be particularly effective and efficient in the removal of ink from waste paper, particularly when used in froth flotation processes as described below, when the anionic surfactant component is used in combination 0 with any of several second surfactant components, namely the following.
• One such second surfactant component comprises one or more alkoxylates of straight and/or branched alcohols, which alcohols contain 1 to 10 carbon atoms. 5
• the alcohols are alkoxylated with both propoxy and ethoxy units, such that the resulting alkoxylate has a mole ratio of propoxy units to ethoxy units of 0.5:1 to 2.0:1.
• the ethoxy and propoxy units can be Q present as poly(ethoxy) and poly(propoxy) blocks, or can
• useful alcohol alkoxylates include any of this formula which can form the desired surfactant composition of the present invention exhibiting the desired properties described herein.
• range of molecular weights, or chain lengths, of alcohol alkoxylates of the foregoing description which are useful in the compositions of the present invention vary rather widely.
• An alcohol alkoxylate of the foregoing description will be effective depending on the other components of the composition, but for illustrative purposes it should be understood that the molecular weight of useful alcohol alkoxylates of the foregoing description may generally range from about 1000 to about 10,000, without intending to be bound by the precise numerical values.
• Satisfactory alkoxylated alcohols meeting the foregoing descriptions can be readily synthesized using established industrial synthesis techniques, although numerous examples of satisfactory alkoxylated alcohols are commercially available.
• One exemplary commercially available alkoxylated alcohol is "Witconol NS-500LQ", a high molecular weight alkoxylated butanol .
• the propoxy and ethoxy units can be interspersed or can be present as blocks formed from each type of unit.
• the number of moles of alkoxy units in the dialkoxylated diacid can fall within the range of chain lengths which still enable the alkoxylated diacid to function effectively in the surfactant composition as described herein.
• dialkoxylated diacids will generally contain up to 75 alkoxy units, and preferably 20 to 60 alkoxy units in total .
• the compounds can have a molecular weight in the range of about 1200 to about 3000.
• Alkoxylated diacids of this description can be readily formed by reacting the corresponding diacid, which is commercially available, with an appropriately chosen number of moles of ethylene oxide and propylene oxide under conventional alkoxylating conditions. Satisfactory diacids include "Westvaco Diacid 1550” and “Westvaco Diacid 1575", available from the Westvaco Corp. in which the principal diacid component corresponds to formula (B-2) wherein the substituent R 2 is H. These diacids are disclosed more generally in U.S. Patent No. 3,899,476.
• each of the R 3 groups is independently C ⁇ -C ⁇ 2 alkyl and A is a halide, acetate, phosphate, methyl sulfate, or ethyl sulfate anion.
• one of the R 3 groups is methyl and two R 3 groups are ethyl. More preferably, A represents chloride .
• Propoxylated quaternary ammonium compounds of the foregoing formula (A.2.c) can readily be synthesized, and several examples are commercially available. More specifically, compounds known as "Emcol CC-9" and “Emcol CC-42", which are propoxylated methyl diethyl quaternary ammonium compounds of the foregoing formula containing, respectively, 9 and 40 propoxy units, are commercially available from Witco Corp.
• anionic surfactant component on the one hand, and the second surfactant component on the other hand which as defined hereinabove can be alcohol alkoxylate, dialkoxylate of cyclohexenyl diacids, or propoxylated quaternary ammonium compounds, are present 0 together in amounts relative to each other effective to aid in the removal of ink from the waste paper.
• the weight ratio of the anionic surfactant or surfactants to the second surfactant should be from 20:1 to 1:20. More preferably, the weight ratio of the anionic surfactant component to the second surfactant component is about 5:1 to 1:1, and more preferably about 4:1 to about 1.5:1.
• surfactant compositions useful o ln accordance with the present invention comprise mixtures of fatty acid alkoxylate, a fatty alcohol alkoxylate, and a third surfactant component.
• the fatty acids represent one or a blend of fatty acids containing 12 to 18 carbon atoms.
• the alkoxylate portion contains 10-30 ethoxy units and 5-25 propoxy units.
• the fatty alcohol alkoxylate is preferably derived from fatty alcohols containing 16 to 20 carbon atoms, and is substituted with an alkoxylate chain containing propoxy and ethoxy units in a Q propoxy:ethoxy mole ratio of 0.5:1 to 2.0:1.
• the fatty alcohol alkoxylate should exhibit a molecular weight in the range of about 1000 to about 3000.
• a mixture " of the fatty acid alkoxylate and fatty alcohol alkoxylate with a third surfactant exhibits exemplary results in the deinking of waste paper, especially when the third surfactant is an alkoxylate of a cyclohexenyl diacid as defined hereinabove with respect to alkoxylates of diacids of the formula (B-2) , and when the third surfactant is an alkoxylate of straight or branched C, - C, resume alcohol as described hereinabove.
• the weight ratio of the fatty acid alkoxylate to the fatty alcohol alkoxylate is from 1:1 to 10:1
• the ratio of the fatty acid alkoxylate plus fatty alcohol alkoxylate to the third surfactant component is from 1:20 to 20:1, but is preferably in the range of 5:1 to 1:1 and more preferably about 2:1 to 1:1.
• the .surfactant formulations of the present invention can be produced by simply combining the indicated surfactant components in the desired relative amounts, such as by stirring in a suitable tank until the components are thoroughly and homogeneously intermixed.
• Water may be present, in an amount ranging 1 from 0.1 wt.% to 90 wt.% depending on the desired final concentration of active ingredients.
• effective deinking is provided by intimately contacting the waste paper with any of the surfactant formulations of the present invention, preferably in an aqueous or other liquid medium to provide desired fluidity and penetration of the surfactant components to the paper/ink interface.
• the waste paper is first shredded or 0 otherwise converted to small pieces so as to improve the contact of the paper and ink with the liquid medium bearing the surfactants.
• appropriate agitation can be provided to enhance the desired contact between the surfactant components and the paper/ink 5 interface.
• the surfactant compositions of the present invention in connection with the froth flotation of ink from the waste paper.
• the general conditions of froth flotation deinking o techniques are known in this field.
• the waste paper is pulped in an aqueous bath, which has preferably been rendered alkaline by appropriate adjustment of the pH via the addition of a base such as sodium hydroxide.
• a base such as sodium hydroxide.
• the pH is about 9 to 11.
• the desired surfactants are added at amounts calculated to provide the desired ratio between amounts of the respective compounds.
• the overall amount of surfactant is selected with respect to the quantity of the paper in the cell and with respect to the general amount of ink product on Q the paper. Generally, the total amount of surfactant
• the flow of gas, typically air, through the flotation cell agitates the liquid medium and the waste paper, provides enhanced contact with the surfactant, and propels ink particles removed from the waste paper to the top surface where a froth rich in removed ink is established.
• the froth can be removed continuously or intermittently.
• the pulp of deinked waste paper is removed from the cell for further processing toward the recovery and reuse in regenerated paper products.
• the present invention has been found to provide improved effectiveness and efficiency in the deinking of waste paper, particularly waste paper comprising mixtures of different types of paper.
• the enhanced deinking has been determined through analysis for the gain in brightness of the recovered paper product and for the percentage of ink removed, (in total and as large particle removal) , as well as for the percentage of fiber recovered in the regenerated product .
• the following examples demonstrate the significant and favorable results that are obtained in the practice of the present invention.
• the feed material to be deinked was repulped in a commercial pulping apparatus (Morden Slushmaker) .
• the feed material comprised about 90 wt.% ledger paper and about 10% copier paper (i.e. that had been printed on by a conventional photocopying machine) .
• the ink formulations present contained hydrocarbon resins used as binders for pigments.
• Each batch contained 4 pounds of paper (dry weight) which was combined with enough water to form a pulp which comprised about 6 wt.% paper. This pulp was maintained in this apparatus for thirty minutes at about 120°F at a pH of 10 to which it had been adjusted with sodium hydroxide.
• Each repulped batch was then diluted with water to 0.8 wt.% consistency and the temperature was adjusted to 100°F, after which portions of the resulting pulp were transferred from the pulping tank into a conventional deinking flotation cell. Once the flotation cell was full and the flow of water through the cell was adjusted to 15 gallons per minute, each of the surfactant compositions described below were added in separate runs. All surfactant compositions used were diluted to 68.1 grams per liter and were added at either 0.3, 0.6 or 0.9 wt. % (based on total dry solids of surfactants weight) . The surfactants added were allowed to mix for five minutes in the cell prior to starting air flow through the cell. Then, air flow upwards through the cell was started and adjusted to 8 cubic feet per minute and the cell was operated for an additional 10 minutes.

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• Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Toxicology (AREA)
• Paper (AREA)
• Detergent Compositions (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

Priority Applications (6)

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Publications (1)

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Family Applications (1)

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Cited By (1)

Citations (4)

• 1996
  • 1996-10-10 BR BR9606708A patent/BR9606708A/pt not_active Application Discontinuation
  • 1996-10-10 CA CA 2207328 patent/CA2207328A1/en not_active Abandoned
  • 1996-10-10 EP EP96936434A patent/EP0797701A1/en not_active Withdrawn
  • 1996-10-10 AU AU74436/96A patent/AU7443696A/en not_active Abandoned
  • 1996-10-10 JP JP51590197A patent/JPH11501704A/ja active Pending
  • 1996-10-10 WO PCT/US1996/016389 patent/WO1997014844A1/en not_active Ceased
  • 1996-10-16 AR ARP960104763 patent/AR003897A1/es unknown
• 1997
  • 1997-06-16 NO NO972765A patent/NO972765L/no unknown

Patent Citations (4)

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