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
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
• • 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
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• • 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
• • 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
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
  • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/24—Addition to the formed paper during paper manufacture
  • D21H23/26—Addition to the formed paper during paper manufacture by selecting point of addition or moisture content of the paper

Definitions

• the present invention is directed to the papermaking arts, more particularly to a process for the manufacture of a paper having improved grease and water resistance, yet facilitating recycling of the paper.
• Such papers throughout the specification and claims "papers” includes virgin or recycled paper, kraft stock and similar materials) find particular application in the container making art wherein such improved properties are desirable.
• the container making art particularly, in the field of corrugated containers, folding cartons, and the tray and box industries, consumes much of the natural timber resources. Thus, it would be beneficial to formulate new processes of forming papers of improved grease and water resistance properties which would be recyclable.
• a • 'furnish (a "furnish” is predominantly water, e.g. , 99.5 % by weight and 0.5% "stock” ("stock” being virgin, recycled or mixed virgin and recycled pulp of wood fibers, fillers, sizing and/or dyes) is deposited from a headbox on a "wire” (a fast-moving foraminous conveyor belt or screen) which serves as a table to form the paper.
• a "wire” a fast-moving foraminous conveyor belt or screen
• the paper After the paper leaves the "wet end" of the papermaking machine, it still contains a predominant amount of water. Therefore, the paper enters a press section, which can be a series of heavy rotating cylinders, which press the water from the paper, further compacting it and reducing its water content, typically to 70% by weight.
• a press section which can be a series of heavy rotating cylinders, which press the water from the paper, further compacting it and reducing its water content, typically to 70% by weight.
• a drying section is the longest part of the paper machine. Hot air or steam heated cylinders contact both sides of the paper, evaporating the water to a low level, e.g. , 5 % by weight of the paper.
• the paper optionally passes through a sizing liquid to make it less porous and to help printing inks remain on the surface instead of penetrating the paper.
• the paper can go through additional dryers that evaporate the liquid in the sizing and coating.
• Calenders or polished steel rolls make the paper even smoother and more compact. While most calenders add gloss, some calenders are used to create a dull or matte finish.
• the paper is wound onto a "parent" reel and taken off the paper making machine.
• the paper on the parent reel can be further processed, such as on a slitter/ winder, into rolls of smaller size or fed into sheeters, such as folio or cut-size sheeters, for printing end uses or even office application.
• rolls formed by slitter/winder e.g. , of paper and kraft grades of liner
• Waxes impart water resistance and wet strength to the liner but inhibits recycling the used containers incorporating them.
• the prior art wax coated liners must be adhered to the other components of the container with hot melt adhesives. These hot melt adhesives are a further impediment to recycling of formed containers employing wax coated components.
• the invention is directed to a process for making paper wherein a furnish is deposited on a wire and dewatered, characterized in: adding to the furnish a recyclable plastic coating.
• the invention is directed to a process for making paper wherein a furnish is deposited on a wire and dewatered to form a paper, and the dewatered paper is subsequently pressed a number of times to further reduce the water content of the paper, characterized in adding a recyclable plastic coating to at least one side of the dewatered paper subsequent to a first pressing step.
• the invention is directed to a process for making paper wherein a furnish is deposited on a wire and dewatered.
• a further embodiment discloses a process for making paper characterized in the following steps:
• Fig. 1 is a perspective, schematic view of a typical paper-making machine.
• Fig. 2 is a schematic, side view of an alternative coating method.
• FIG. 1 A typical paper making machine is illustrated generally at 10 in Fig. 1 .
• a "wet end" 1 1 including a headbox 12, a wire 13 and a press section 15, a drying section 16, a size press 18, calender section 20 and parent reel 22.
• a dandy roll 14 is positioned about two thirds of the way down the wire to level the fibers and make the sheet more uniform.
• Gravity and suction boxes are positioned underneath the wire to remove water from the furnish.
• the stock fed to the headbox 12 can be virgin, recycled or a mixture of virgin and recycled pulp.
• the stock is mixed with water to form a furnish for deposit onto the wire.
• RPC recyclable plastic coating
• a typical (RPC) composition is an aqueous acrylic resin based composition.
• a 35% solids polyethylene wax emulsion having the following typical properties:
• Non-volatiles 34.7 -35.3% pH 9.0 - 9.5
• Components A. B and C are mixed in approximate parts by weight of 15:65:6 in admixture with 5.5 HOH, 0.5 NH 4 OH, 3 zinc oxide "solution” (actually a dispersion), under strong agitation. All of the foregoing proportions can be varied plus or minus 10% and still display the performance of the RPC. In tact, Component A and B can be varied plus or minus 20% and Component C can be completely removed from the formulation or be substituted by other synthetic polyethylene waxes while still achieving the desired results of the invention.
• the percent solids of the composition supplied to headbox 12 or used at other coating locations according to the invention can typically be varied from about 3.0% to about 20% by weight.
• Components A, B and C are mixed in approximate parts (by weight) of 15:65:6 in admixture with 5.5 HOH, 0.5 NH OH, 3 zinc oxide solution, under strong agitation.
• the Components A, B and C, to be used in formulating the composition of the invention are commercially available from S.C. Johnson & Sons, Inc. , U.S. Specialty Chemicals, 1525 Howe Street, Racine, Wisconsin under the trademarks JONCRYL 61LV, JONCRYL 82 and JONCRYL 28, respectively.
• JONCRYL 82 is a polymeric composition compatible with various solvents including methanol, 3 A ethanol, isopropanol, n-propanol, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, acetone, methylene ketone and methyl isobutyl ketone.
• Heat resistance of JONCRYL 82 can be further increased by crosslinking the polymer with a zinc oxide solution which produces stable viscosities at higher pH.
• the maximum workable pH of JONCRYL 82 can be increased from 7 to 9 by incorporating a zinc oxide solution.
• JONCRYL 61LV can be formulated in a ball-mill or high shear dispersion of up to 40% organic and 70% inorganic pigment. Unlike other acrylic polymer dispersions, JONCRYL 61LV does not become thixotropic at high pH. JONCRYL 61LV is compatible with caseins, shellacs and resin ester maleics, as well as other acrylic resins.
• aqueous composition can be incorporated in the stock or finished paper.
• the following Examples will demonstrate the wide variation in RPC content.
• liner board was repulped to conform with the consistency of pulped fiber processed in an average paper mill machine. At this point, the fiber was separated into four separate beakers each with 100 grams of fiber. To beaker number 1 , 5.0 grams of RPC was added. In beaker number 2, 10.0 grams of RPC was added. In beaker number 3, 20.0 grams of RPC was added. In beaker number 4, 30.0 grams of RPC was added.
• the fiber from each beaker was applied to a wire mesh which would simulate the wire mesh of a paper machine which allows the fiber to drain by gravity or assisted through a particle vacuum action that starts the removal of fluids on the paper machine.
• excess fluids were driven out of the fiber of each test sample, one through four.
• the final phase was to repulp samples one through four, rescreen and dry.
• the final step in the process to determine success is examining the dry reformed paper under a microscope to determine the presence of undissolved foreign matter that would indicate a failure to repulp. The examination revealed that no undissolved material were present, indicating success in creating a barrier and having the barrier, RPC, dissolve and allow no foreign matter to be present in any beaker marked one through four.
• the foregoing experiment is indicative of addition of RPC to the stock or furnish prior to deposit on the wire of a paper making machine.
• the next step in taking the invention from the laboratory to a commercially viable process was to introduce the RPC at different locations in conventional paper making machines.
• a position on the paper machine downstream of the headbox 12 was selected for a manual "pour on” of liquid RPC on an edge of the paper approximately 24 inches (58.8 cm) of the width of the paper machine, in the amount of 5 gallons ( 18.92 1).
• This section of treated paper was tracked through the paper machine and retrieved at the dry end of the machine. This retrieval section was tested for grease and water resistance and showed improvement in both areas.
• RPC was next applied with a spraybar, the application rate applied from a minimum value, but sufficient to create perceptible enhancements to liner or medium, to approximately 40% by weight of paper, pH varied from 5.5 to 8.0.
• the RPC was applied at the wet end via spray application to the top side of the sheet during a run of 26# medium.
• the trial spray head was positioned at:
• coating on both sides of a moving paper web 24 can be effected by passing web 24 between the nip of rollers 26, 28 in which a bank 30 of RPC is found thereby applying the RPC to one side of web 24.
• the other side of the web 24 can be coated by bank 40 and rollers 36, 38. Additional layers of coating may be applied one or more times to either or both sides of web 24 by additional rollers 46, 48, 56, 58 and banks 50 and 60.
• Additional idler rolls 42, 52 may be provided to convey and tension web 24.
• the device of Fig. 2 can be used prior to, subsequent to or in place of size press 18 of Fig. 1. It should be understood that additional rollers (not shown), banks (not shown) and even idler rolls (not shown) may be employed to apply as many additional layers of RPC as desired. Additionally, sizing agents may be incorporated into one or more of the banks of RPC.
• the papers coated by the process find special use in the following industries, the label industry, especially the 60#/3000 S.F. label industry, folding carton, tray and box (all board weights) and liquid packs, such as water, soda, and milk, ice cream, yogurt and delicatessen carry-out containers.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)

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Publications (1)

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Citations (3)

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• 1995
  • 1995-01-06 CA CA002184489A patent/CA2184489C/en not_active Expired - Lifetime
  • 1995-01-06 AU AU16761/95A patent/AU1676195A/en not_active Abandoned
  • 1995-01-06 EP EP95908441A patent/EP0749508B1/en not_active Expired - Lifetime
  • 1995-01-06 DE DE69526495T patent/DE69526495T2/de not_active Expired - Lifetime
  • 1995-01-06 AT AT95908441T patent/ATE216742T1/de not_active IP Right Cessation
  • 1995-01-06 WO PCT/US1995/000187 patent/WO1996021061A1/en active IP Right Grant
• 1996
  • 1996-09-05 FI FI963481A patent/FI121935B/fi not_active IP Right Cessation

Patent Citations (3)

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