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
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/04—Physical treatment, e.g. heating, irradiating
  • D21H25/06—Physical treatment, e.g. heating, irradiating of impregnated or coated paper
• • 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
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/02—Chemical or biochemical treatment
• • 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
• • 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
  • D21H17/04—Hydrocarbons
• • 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
  • D21H17/07—Nitrogen-containing compounds
• • 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
  • D21H17/14—Carboxylic acids; Derivatives thereof
• • 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
  • D21H17/17—Ketenes, e.g. ketene dimers
• • 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
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/16—Sizing or water-repelling agents

Definitions

• the technical field relates to compositions containing sizing agents useful in the paper industry and to a method of treating a paper substrate with such compositions.
• Cellulose which is the main component of paper substrates, is hydrophilic and polar. These characteristics result in rapid water penetration in the paper substrate. This phenomenon can be delayed by hydrophobation of the paper substrate. This operation is known as “paper sizing.” By this operation, the penetration of polar liquids (e.g., water or inks) in the paper is delayed by recovering the cellulose fibers with a hydrophobic substance, which is called a sizing agent.
• the sizing agent is usually added to the paper pulp and retained by the cellulose fibers in the wet end part of the paper manufacturing process. This is called internal sizing. However, the sizing agent can also be applied to the surface of the dried or partially dried paper, i.e., surface sizing.
• Typical sizing agents include rosin, alkenyl succinic anhydrides (“ASAs”) and alkyl ketene dimers (“AKDs”).
• ASAs are good candidates for surface sizing of paper substrates due to their high reactivity towards the hydroxyl groups of the cellulose.
• the reaction between ASAs and cellulose can be represented as follows:
• the ASA is generally emulsified in water and the emulsion is applied using a sizing press or a coater.
• ASA emulsion can also, but less often, be applied using a shower.
• some curl problems have been observed when applying ASA water emulsions using showers.
• the particle size has to be controlled and a limited particle size range must be obtained.
• the water emulsion containing ASA must also be used quickly so as to limit ASA's hydrolysis, which produces a product interfering with sizing.
• ASA in gaseous phase contacts the paper surface and reacts with the hydroxyl groups of the cellulose.
• applying such a method at an industrial scale would imply using a complex system in order to avoid releasing ASA in the atmosphere surrounding the machine.
• a complicated system would be required for confining the molecules in gaseous phase while allowing their contact with the paper sheet in continuous movement.
• a water-free surface sizing composition comprising at least one alkenyl succinic anhydride and at least one biosolvent for adjusting a viscosity of the composition to allow spraying thereof on a paper surface.
• a method for treating a paper substrate with the water-free surface sizing composition comprising spraying the composition onto the surface of the paper substrate and heating the paper substrate treated with the composition.
• the water-free surface sizing composition for providing water resistance or improving water resistance of a paper substrate.
• a water-free sizing composition providing water-resistance to the surface of paper substrates will be described.
• paper substrate refers to any type of cellulosic fiber-based substrate including, for example, and without being limited to, any suitable wood-fiber based material, such as recycled or virgin liner, medium, chipboard, paperboard, folding carton, kraftpak paper, bag paper, fine paper and the like.
• the cellulose in the cellulosic fiber-based substrate is accessible for surface treatment.
• hydroxyl groups of the cellulose included in the paper substrate are accessible for reacting with the ASA molecules of the water-free composition. If the cellulose in the paper substrate has previously been surface treated, for example, with starch, remaining hydroxyl groups have to be accessible for reacting with the ASA of the water-free composition.
• the cellulose in the paper substrate to be treated with the water-free sizing composition containing ASA has not been subjected to a previous surface treatment.
• the paper substrate may have been subjected to an internal sizing treatment prior to the surface treatment with the water-free composition.
• the internal sizing treatment may be carried out using any sizing agent known in the art for internal treatment.
• the internal sizing agent can be an AKD or an ASA.
• an ASA is used as internal sizing agent, it can be the same or different than the ASA present in the water-free composition with biosolvent.
• the sizing composition is a water-free or substantially water-free solution of at least one ASA in a biosolvent.
• the composition has a viscosity that allows it to be sprayed on the paper substrate.
• sprayed or “spraying”, it is meant that the composition is applied as a liquid broken up into minute droplets being blown, ejected into, or falling through the air to then reach the surface of the paper substrate.
• the composition is applied to the paper surface in the liquid state either using a shower or by discharge from a pressurized container through spray nozzles.
• ASAs are liquid products having a relatively high viscosity.
• Mixing the ASA with a biosolvent or mixture of biosolvents preferably reduces the viscosity of the ASA in the resulting composition.
• the composition can be applied by spraying on the paper substrate. This results in a substantially homogeneous distribution of the ASA onto the paper surface.
• the ASA is thus allowed to react with accessible hydroxyl groups of the cellulose in the paper substrate and hydrophobicity of the paper substrate is thus increased.
• the ASAs that can be used in the composition include any ASA commonly used as an internal sizing agent in the paper industry. It is also possible to use a mixture of different ASAs in the composition.
• the ASA has an alkenyl group of from 16 to 20 carbon atoms. In another embodiment the ASA has an alkenyl group of from 16 to 18 carbon atoms.
• the composition contains a mixture of ASAs wherein each has from 16 to 20 carbon atoms in its alkenyl group.
• the double bond of the alkenyl group can be in any position on the alkenyl chain.
• the ASA used in the composition include hexadecenyl succinic anhydride, octadecenyl succinic anhydride or any mixture thereof, wherein the double bond of the alkenyl group is in any position on the alkenyl chain.
• the ASA added to the composition is present in the product NALSIZE® 7542, sold by Nalco Company, or HYDRORESTM AS 2300, sold by Kemira Chemicals.
• NALSIZE 7542 is a mixture of ASAs (C 16 -C 18 ) containing up to 2% nonionic surfactant.
• HYDRORES AS 2300 is ASA having a linear alkenyl chain of 18 carbon atoms.
• the ASA or mixture of ASAs are combined with at least one biosolvent to decrease the viscosity of the ASA(s).
• a mixture of biosolvents can be used to achieve the required viscosity.
• the mixture ASA(s)-biosolvent(s) is a liquid solution that is substantially homogeneous.
• Biosolvents as opposed to petroleum-derived solvents, are solvents from natural origin which are issued from treated or untreated plant, animal or mineral raw materials.
• biosolvents include dipentene, the racemic of (+) and ( ⁇ ) limonene. It is also possible to use only one of the enantiomers of limonene.
• biosolvents to be used in the composition include fatty acid esters and fatty acid amides.
• the fatty acid esters or amides are either saturated or unsaturated.
• the fatty acid esters are fatty acid methyl esters and the fatty acid amides are N,N-dimethyl fatty acid amides.
• the aliphatic chain of the fatty acid esters has from 8 to 18 carbon atoms. Examples of fatty acid esters include methyl caprylate, methyl laurate, methyl oletate, or methyl palmitate.
• the aliphatic chain of the fatty acid amides has 8 or 10 carbon atoms.
• the fatty acid amides may be N,N-dimethylcaprylamide or N,N-dimethylcapramide.
• the use of a biosolvent or a mixture of biosolvents can be utilized to decrease the viscosity of the ASAs, thereby obtaining a sizing composition that is sprayable.
• the biosolvent and its relative amount in the composition are determined to achieve a composition with a viscosity of about 100 cPs or less.
• the composition has a viscosity of from about 25 to about 100 cPs. In some embodiments, the viscosity of the composition can be between about 25 and about 90 cPs.
• the sizing composition has a flash point of at least about 50° C.
• the value of the flash point of the composition will principally depend on the nature and proportions of the biosolvent(s) used in the composition.
• the proportion of ASAs is also taken into account. ASAs have high flash points and contribute to an increase of the flash point of the composition. A person skilled in the art will be able to choose the appropriate biosolvents and to estimate the proportions thereof to obtain a composition with an appropriate flash point.
• the flash point is chosen so as to minimize flammability risks of the composition in the dryer or through the contact with hot surfaces during the sizing process.
• the flash point of the composition may be of at least about 93° C.
• the surface sizing composition is obtained by mixing the ASA or mixture of ASAs with the biosolvent or mixture of biosolvents.
• the ASA or mixture of ASAs are added in about 1 wt % to about 80 wt % of the weight of the composition.
• ASA(s) represent(s) about 40 wt % to about 70 wt % of the weight of the composition.
• the biosolvent or mixture of biosolvents can be present in about 20 wt % to about 99 wt % of the weight of the composition, or in about 30 wt % to about 60 wt % of the weight of the composition.
• the surface sizing composition comprises about 60% w/w of ASA and about 40% w/w of biosolvent or mixture of biosolvents.
• the ASA can be NALSIZE 7542 and the biosolvent a mixture of biodiesel and limonene.
• Table 1 below provides examples of sizing compositions according to specific embodiments.
• Composition 1 Composition 2 NALSIZE 7542 60% w/w 60% w/w Biodiesel 38% w/w 35% w/w Limonene 2% w/w 5% w/w Viscosity 50 rpm, spindle #1 43 cp 41 cp Flash point 107° C. 95° C.
• the method generally involves spraying the composition onto the surface of the paper substrate and then heating the treated substrate.
• the paper substrate which can be a recycled or virgin liner, medium, chipboard, folding carton, kraftpak paper, paperboard, bag paper, fine paper or any other cellulosic fiber-based substrate, is provided to the sizing machine where the composition is allowed to be sprayed on its surface using a sprayer.
• the composition is applied to the paper surface in the liquid state using a shower or any spray equipment commonly known in the art.
• the composition can be applied by discharge from a pressurized container through a multi-nozzles spraying system.
• the composition can be applied using a rotor damping system, for instance a WEKO-RFT Rotor Damping System.
• the nozzles can be appropriately placed across the width of the paper machine. The spray nozzles are designed and spaced to ensure even distribution of the composition on the paper sheet.
• the composition is applied at room temperature on the paper surface.
• the quantity of composition applied to the surface of the paper substrate may depend on the type of substrate and the intended water barrier. In an embodiment, the quantity of composition applied to the surface of the paper substrate is from about 0.2 to about 10 g/m 2 . In another embodiment, the quantity of composition applied to the surface of the paper substrate is from about 0.2 to about 2 g/m 2 .
• the treated paper is then passed through a dryer or heater to provide the energy required to allow the reaction between the hydroxyl groups of the cellulose included in the paper and the ASA molecules, and the surface of the substrate becomes hydrophobic.
• dryers/heaters commonly used in paper making processes are adapted for heating the paper treated with the water-free composition and there is no need to modify their temperature.
• the water-free surface sizing composition once applied to the paper and after heating thereof, provides good water resistance properties to the paper.
• the so treated paper can show Cobb 2min values from about 27 g water /m 2 to about 50g water /m 2 .
• the so treated paper can be used in many applications, for example, printing paper, linerboard, for folding box and protective headers.
• the present water-free sizing composition and the way it is applied to the paper substrate show various advantages over known paper sizing methods.
• the use of a water-free sizing composition allows avoiding paper curl problems that can be observed when applying water based sizing compositions using showers.
• the present water-free composition thanks to the biosolvents it contains, is more environmentally friendly than compositions containing petroleum based solvents.
• Water-free surface sizing compositions have been prepared as summarized in Table 2. Their viscosities and flash points have been determined and are also reported in Table 2.
• compositions B1, B2 and B3 of Table 1 were tested to evaluate their sizing properties.
• 2.4 g paper handsheets were prepared using brown pulp (100% old corrugated containers (“OCC”)).
• OCC old corrugated containers
• the retention system was composed of 0.6 kg/t PERCOL® 3320 CB (“C-PAM”) (polyacrylamide, available from BASF) and 4 kg/t LUREDUR® 8097 (partially hydrolyzed polyvinyl formamide, available from BASF).
• C-PAM polyacrylamide
• LUREDUR® 8097 partially hydrolyzed polyvinyl formamide, available from BASF
• compositions were applied onto the surface of the 2.4 g paper handsheets using an aerograph.
• the liquid compositions were uniformly vaporized using compressed air.
• the handsheets were then dried at 105° C. for 15 minutes and left for 5 days at 23° C. under 50% relative humidity.
• Cobb 2 min values were then measured. The results are reported in Table 3. Measurements were also performed for an untreated paper handsheet for comparison. The Cobb 2 min for the untreated substrate was above 220 g water /m 2 .
• a composition was prepared by mixing 60% (w/w) NALSIZE 7542 as ASA, and a mixture of 35% (w/w) biodiesel and 5% (w/w) limonene as biosolvent.
• the composition was applied to the surface of a cardboard (recycled paper; basis weight 679 g/m 2 ), at the mill before the dyer section, using a spray gun.
• the sizing efficacy was studied over time by measuring Cobb values four times within a period of one year and 4 months.
• the treated cardboard was not oven-dried.
• the untreated surface allowed water penetration into the cardboard on the Cobb 2 min test (about 967 g water /m 2 ).

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• 2014
  • 2014-06-13 EP EP14810220.5A patent/EP3008241B1/fr active Active
  • 2014-06-13 KR KR1020167000501A patent/KR102240361B1/ko active Active
  • 2014-06-13 JP JP2016519674A patent/JP6407984B2/ja active Active
  • 2014-06-13 CA CA2910668A patent/CA2910668C/fr active Active
  • 2014-06-13 US US14/303,851 patent/US20150010712A1/en not_active Abandoned
  • 2014-06-13 CN CN201480033229.3A patent/CN105283601B/zh active Active
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