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
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
• • 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
  • D21H15/00—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
  • D21H15/02—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution characterised by configuration
  • D21H15/06—Long fibres, i.e. fibres exceeding the upper length limit of conventional paper-making fibres; Filaments
• • 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
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
  • D21H17/675—Oxides, hydroxides or carbonates
• • 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
  • D21H17/63—Inorganic compounds
  • D21H17/70—Inorganic compounds forming new compounds in situ, e.g. within the pulp or paper, by chemical reaction with other substances added separately
• • 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
  • D21H21/50—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 form
  • D21H21/52—Additives of definite length or shape

Definitions

• the present invention relates to a paper or paperboard substrate containing fiber-filler complexes as well as methods of making and using the same.
• Inorganic material such as precipitated calcium carbonate (PCC) ground calcium carbonate (GCC), clay and talc are used extensively as fillers in the paper making process. Filler loading levels of 12-25wt% are typical in current paper making strategy to improve optical properties of the paper such as brightness and opacity. In some instances, the economics of substituting expensive fiber with inexpensive filler lends added incentive.
• PCC precipitated calcium carbonate
• GCC ground calcium carbonate
• talc are used extensively as fillers in the paper making process. Filler loading levels of 12-25wt% are typical in current paper making strategy to improve optical properties of the paper such as brightness and opacity. In some instances, the economics of substituting expensive fiber with inexpensive filler lends added incentive.
• retention aids are used. Normally retention aids are long chained polymeric compounds that flocculate the furnish and enhance filler-fiber "attachment.” However, high flocculation levels, caused in part by retention aids, lead to non-uniformity in the web and poor paper formation.
• the crystals of precipitated calcium carbonate (PCC) are organized essentially in clusters of granules directly grafted on to the microfibrils without any binders or retention aids such that the crystals trap the microfibrils by reliable and non-labile bonding.
• Srivatsa et al. describes in situ precipitation on secondary fiber furnish.
• the Cousin et al. patents describe a batch reaction process
• Matthew et al. describes a continuous process for forming fiber-filler complexes.
• One aspect of the present invention is a paper substrate, containing a plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average and having a filler attached thereto a portion of said plurality and also containing less than 50wt % fibers that are less than 75 ⁇ m in length on average based upon the total weight of the substrate.
• the fibers that are hardwood species, softwood species or mixtures thereof may have a Canadian Standard Freeness of from 300 to 600 and may be virgin fibers.
• the fibers that are less than 75 ⁇ m in length on average may be recycled fibers, recirculated fibers, waste fibers, or mixtures thereof.
• the fibers that are less than 75 ⁇ m in length may be present in an amount that is from 0.1 to 20wt% based upon the total weight of the substrate.
• Another aspect of the present invention is a paper substrate, containing a plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average and having a filler attached thereto a portion of said plurality and also containing less than 50wt % fibers that are less than 75 ⁇ m in length on average based upon the total weight of the substrate where the filler is present in an amount of from 1 to 30wt% based upon the total weight of the substrate.
• the filler maybe attached at a filler to fiber weight ratio of from 0.3 to 8.
• the filler maybe precipitated. Further, the filler maybe precipitated calcium carbonate.
• the filler may be in at least one shape of selected from the group consisting of cubic, scalenohdral, rhombic, and aragonite.
• the filler has an average particle size of from 0.01 to 20 ⁇ m.
• Another aspect of the present invention is a method of making a paper substrate by contacting a plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average and having a filler attached thereto a portion of said plurality with fibers that are less than 75 ⁇ m in length on average based upon the total weight of the substrate.
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with Ca(OH)2 and/or CO 2 simultaneously and/or sequentially.
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average in-line with Ca(OH) 2 to form a slurry having less than 5% solids.
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with CO 2 gas prior to contacting the plurality of fibers with Ca(OH) 2 .
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with CO 2 gas prior to contacting the plurality of fibers with Ca(OH) 2 .
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with Ca(OH) 2 and/or CO 2 simultaneously and/or sequentially at a pH of from 7.5 to 11.
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with Ca(OH) 2 and/or CO 2 simultaneously and/or sequentially in a tubular reactor, wherein CO 2 is added to the reactor at multiple addition points.
• Another aspect of the present invention is a method of making a paper substrate by contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average with Ca(OH) 2 and/or CO 2 simultaneously and/or sequentially in a series of continuous stirring tank reactor, wherein CO 2 is added to each of the continuous stirring tank reactor in the series.
• Another aspect of the present invention is a method of making a paper substrate by contacting both the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 ⁇ m in length on average and the fibers that are less than 75 ⁇ m in length on average with Ca(OH) 2 and/or CO 2 simultaneously and/or sequentially in a series of continuous stirring tank reactor, wherein CO 2 is added to each of the continuous stirring tank reactor in the series.
• FIG. 1 A plot of Sheffield smoothness, in Sheffield Units (SU), of the ID side of a paper substrate versus the wt% ash contained in that paper substrate.
• FIG. 2 A plot of Sheffield smoothness, in Sheffield Units (SU), of the NS side of a paper substrate versus the wt% ash contained in that paper substrate.
• FIG. 3 A table comparing the fluorescence of the residual OBA from a SaveAll fiber fine stream sample before and after the sample is reacted to form the fiber fine-filler complex.
• FIG. 4 is a schematic diagram of a process employing several of the features of the present invention.
• FIG. 5 is a schematic representation of one embodiment of an apparatus for carrying out the process of the present invention.
• FIG. 6 is a schematic representation of one embodiment of a process, combined with apparatti for carrying out the process of the present invention.
• FIG. 7 is a schematic representation of one embodiment of a process to make a fiber-filler complex where a (plug flow) reactor is used and a series of CO 2 addition occur throughout the reactor.
• FIG. 8 is a schematic representation of one embodiment of a process to make a fiber-filler process where multiple continuous stirring tank reactors are used in series.
• FIG. 9 is paper substrate comparison as a function of precipitated filler morphology.
• FIG. 10 is SEM showing morphology results of tubular reactor.
• FIG. 11 is first SEM showing morphology results of CSTR reactor.
• FIG. 12 is second SEM showing morphology results of CSTR reactor.
• FIG. 13 is first SEM showing cubic morphology.
• FIG. 14 is second SEM showing cubic morphology.
• FIG. 15 is third SEM showing cubic morphology.
• FIG, 16 is fourth SEM showing cubic morphology.
• FIG. 17 is a plot of HST sizing vs % PCC.
• FIG. 18 is a plot of Modulus vs % PCC.
• FIG. 19 is a plot of internal bond vs % PCC.
• FIG. 20 is a plot of GM breaking lenght vs % PCC.
• FIG. 21 is a plot of GM Taber Stiffness vs % PCC.
• FIG. 22 is a plot of Brightness with UV vs % PCC.
• FIG. 23 is a plot of Brightness without UV vs % PCC.
• FIG. 24 is a plot of Flourescence (delta Brightness) vs % PCC.
• FIG. 25 is a very preferred embodiment of the process of making the fiber filler complex.
• the present inventors have discovered a method of making a paper or paperboard substrate containing fiber-filler complexes, as well as a method of making the same, that solves all of the above-mentioned problems identified while utilizing conventional paper substrates and methodologies.
• the paper substrate contains a web of cellulose fibers.
• the paper substrate of the present invention may contain recycled fibers and/or virgin fibers. Recycled fibers differ from virgin fibers in that the fibers have gone through the drying process several times.
• the paper substrate of the present invention may contain from 1 to 99 wt%, preferably from 5 to 95 wt%, most preferably from 60 to 80 wt% of cellulose fibers based upon the total weight of the substrate, including 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 99 wt%, and including any and all ranges and subranges therein.
• the sources of the cellulose fibers are from softwood and/or hardwood.
• the paper substrate of the present invention may contain from 1 to 99 wt%, preferably from 5 to 95 wt%, cellulose fibers originating from softwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100wt%, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fibers from softwood species, preferably from 0.01 to 50wt%, most preferably from 5 to 40wt% based upon the total weight of the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fines based upon the total weight of the paper substrate, including any and all ranges and subranges therein.
• the paper substrate may contain softwood fibers from softwood species that have a Canadian Standard Freeness (csf) of from 300 to 700, more preferably from 250 to 650, most preferably from 400 to 550 csf.
• This range includes 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, and 550 csf, including any and all ranges and subranges therein.
• the paper substrate of the present invention may contain from 1 to 99 wt%, preferably from 5 to 95 wt%, cellulose fibers originating from hardwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100wt%, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fibers from hardwood species, preferably from 50 to 100wt%, most preferably from 60 to 99wt% based upon the total weight of the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99 and 100wt% fines based upon the total weight of the paper substrate, including any and all ranges and subranges therein.
• the paper substrate may contain softwood fibers from hardwood species that have a Canadian Standard Freeness (csf) of from 300 to 700, more preferably from 250 to 650, most preferably from 400 to 550 csf.
• This range includes 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, and 550 csf, including any and all ranges and subranges therein.
• the hardwood/softwood ratio be from 0.001 to 1000.
• This range may include 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 including any and all ranges and subranges therein and well as any ranges and subranges therein the inverse of such ratios.
• the hardwood and soft wood fibers are preferably not less than 75 ⁇ m in length on average, more preferably not less than 80 ⁇ m in length, most preferably not less than 100 ⁇ m in length.
• the length of these fibers are greater than or equal to 75, 77, 80, 82, 85, 87, 90, 92, 95, 97, an 100 ⁇ m in length, including any and all ranges and subranges therein and well as any ranges and subranges therein.
• the softwood and/or hardwood fibers contained by the paper substrate of the present invention may be modified by physical and/or chemical means.
• physical means include, but is not limited to, electromagnetic and mechanical means.
• Means for electrical modification include, but are not limited to, means involving contacting the fibers with an electromagnetic energy source such as light and/or electrical current.
• Means for mechanical modification include, but are not limited to, means involving contacting an inanimate object with the fibers. Examples of such inanimate objects include those with sharp and/or dull edges.
• Such means also involve, for example, cutting, kneading, pounding, impaling, etc means.
• Examples of chemical means include, but is not limited to, conventional chemical fiber modification means including crosslinking and precipitation of complexes thereon.
• modification of fibers may be, but is not limited to, those found in the following patents 6,592,717, 6,592,712, 6,582,557, 6,579,415, 6,579,414, 6,506,282, 6,471,824, 6,361,651, 6,146,494, Hl/704, 5,731,080, 5,698,688, 5,698,074, 5,667,637, 5,662,773, 5,531,728, 5,443,899, 5,360,420, 5,266,250, 5,209,953, 5,160,789, 5,049,235, 4,986,882, 4,496,427, 4,431,481, 4,174,417, 4,166,894, 4,075,136, and 4,022,965, which are hereby incorporated, in their entirety, herein by reference.
• Sources of "Fines” maybe found in SaveAll fibers, recirculated streams, reject streams, waste fiber streams.
• the amount of "fines" present in the paper substrate can be modified by tailoring the rate at which such streams are added to the paper making process.
• the paper substate preferably contains a combination of hardwood fibers, softwood fibers and "fines" fibers.
• "Fines" fibers are, as discussed above, recirculated and are typically not more that 100 ⁇ m in length on average, preferably not more than 90 ⁇ m, more preferably not more than 80 ⁇ m in length, and most preferably not more than 75 ⁇ m in length.
• the length of the fines are preferably not more than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 ⁇ m in length, including any and all ranges and subranges therein.
• the paper substrate contains from 0.01 to 100 wt% fines, preferably from 0.01 to 50wt%, most preferably from 0.01 to 15wt% based upon the total weight of the substrate.
• the paper substrate contains not mort than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fines based upon the total weight of the paper, including any and all ranges and subranges therein.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fines, preferably from 0.01 to 50wt%, most preferably from 0.01 to 15wt% based upon the total weight of the fibers contained by the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fines based upon the total weight of the fibers contained by the paper substrate, including any and all ranges and subranges therein.
• the paper substrate in one embodiment of the present invention, may contain less fiber "fines" and more long fresh hardwood and/or softwood fibers, preferably virgin.
• the net affect of the paper substrate is to have a web of cellulose fibers that are more de-bonded than if there were a higher amount of "fines" in the substrate. Utilization of the longer hard long fresh hardwood and/or softwood fibers, preferably virgin, over the fiber fines may result in a less dense sheet containing higher bulk that may be more compressible and uniform resulting in improved smoothness after pressing and/or calendaring.
• Example 1 This ideal is demonstrated by Example 1 below combined with Figures 1 and 2 show a plot of the Sheffield smoothness, in Sheffield Units (SU), of the ID and NS sides, respectively, of a paper substrate versus the wt% ash contained in that paper substrate.
• One paper substrate contained highly refined SaveAU pulp with high surface area, while the other contained unrefined pulp.
• the paper substrate of the present invention may contain a filler.
• Fillers may be inorganic.
• fillers include, but are not limited to; clay, talc, calcium carbonate, calcium sulfate hemihydrate, and calcium sulfate dehydrate.
• a preferable filler is calcium carbonate with the preferred form being precipitated calcium carbonate even though it also may in the form of ground calcium carbonate.
• the paper substrate of the present invention may contain from 0.001 to 50 wt% of the filler based on the total weight of the substrate, preferably from 0.01 to 40 wt%, most preferably 1 to 30wt%, of at least one of the filler.
• This range includes 0.001, 0.002, 0.005, 0.006, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 25, 30, 35, 40, 45 and 50wt% based on the total weight of the substrate, including any and all ranges and subranges therein.
• the paper substrate preferably contains a fiber-filler complex, more preferably a fiber CaCO 3 complex.
• the fiber-filler is a complex in. which the fiber and the filler are engaged in either a chemical and/or physical interaction.
• Methods of making the fiber-filler complex may be any conventional method, including those described in French Patent 92-04474 and U.S. Pat. Nos. 5,731,080; 5,824,364; 5,679,220; 6,592,712, and 5,665,205, which are hereby incorporated, in their entirety, herein by reference. Further embodiments of making the fiber-filler complex is found in Figures 4-6.
• the paper substrate preferably contains a fiber-filler complex that is preferably made by the methods described herein.
• the fiber-filler is a complex in which the fiber and the filler are engaged in either a chemical and/or physical interaction.
• the ratio of the filler to fiber can be any ratio.
• the filler/fiber ratio may be from 0.001 to 1000.
• the filler/fiber ratio may be 0.001, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.5, 3.0, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 225, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, and 1000, including any and all ranges and subranges therein.
• the average particle size of the filler when in the fiber filler complex may be any particle size.
• Examples of the average particle sizes of the filler in the fiber filler complex are those from 0.01 to 20 ⁇ m.
• the average particle size of the filler maybe 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.12, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.2, 5.5, 5.7, 6.0, 6.2, 6.5, 6.7, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20,
• the average surface area of the filler particle in the fiber filler complex may be any particle size.
• Examples of the surface area of the filler particle in the fiber filler complex are those from 0.1 to 20 m 2 /g.
• the surface area of the filler particle in the fiber filler complex may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.12, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, .
• the amount of filler attached the fiber in the fiber filler complex may be from 1 to 100wt% attachment, preferably at least 9wt% attachment, more preferably at least 15wt% attachment, most preferably at least 20wt% attachment based upon the total amount of the filler that is added to the reactor.
• the amount of filler attached the fiber in the fiber filler complex may be at least 1, 2, 3, 5, 7, 10, 12, 15, 17, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 80, 95, and 99wt%, including any and all ranges and subranges therein.
• the filler is preferably precipitated when in the fiber filler complex.
• the filler may be of any shape commonly known that precipitated crystals may form. Examples of shapes may be cubic, scalenohdral, rhombic, and/or aragonite. Preferably, the shapes are cubic and/or aragonite.
• the paper substrate may contain from 0.1 to 100wt% fiber filler complex based upon the total weight of the substrate, including 0.1, 0.2, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100 wt%, and including any and all ranges and subranges therein.
• the fiber filler complex may be made by contacting the fibers, Ca(OH) 2 and/or CO 2 simultaneously and/or consecutively to form a fiber-CaCO3 complex.
• the fibers to be added to create the fiber-filler complex may have from 3 to 200 m 2 /g, including 3, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 275 and 300 m 2 /g, including any and all ranges and subranges therein.
• the fiber-filler complex may be made by adding less than or equal to 5% solids Ca(OH) 2 , including less than or equal to 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0% solids Ca(OH) 2 based upon the weight of the reactants, including any and all ranges and subranges therein. However, any % solids of Ca(OH) 2 may be used.
• the fiber-filler complex may be made by adding less than or equal to % solids CO 2 , including less than or equal to 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0% solids CO 2 based upon the weight of the reactants, including any and all ranges and subranges therein. However, any % solids of COzmay be used.
• the fibers are contacted with CO 2
• the source of the fibers may be any source. Further, the fibers may be premixed with a gas, liquid, and/or solid carrier such as water, but this is not necessary.
• the source Of Ca(OH) 2 may be any source. Further, Ca(OH) 2 and/or its source may be in the form of a gas, liquid and/or solid. Still further, the Ca(OH) 2 and/or its source may be premixed with a gas, liquid, and/or solid carrier such as water, but this is not necessary. Preferably, the Ca(OH) 2 source may be lime.
• the source of CO 2 may be from any source. Further, CO 2 and/or its source may be in the form of a gas, liquid and/or solid. Still further, the CO 2 and/or its source may be premixed with a gas, liquid, and/or solid carrier such as water, but this is not necessary. Preferably, the CO 2 is in the form of a gas and/or liquid.
• the CO 2 may be added to the fibers at any time in the process of making the fiber-filler complex. That is, CO 2 may be added to the fibers before the fibers enter the reactor, reaction zone, and/or contact zone. Also, CO 2 may be added to the fibers when the fibers enter the reactor, reaction zone, and/or contact zone.
• the fiber-filler complex is made by contacting the fibers with CO 2 prior to contacting the fibers with Ca(OH) 2 .
• the fiber filler complex is made by
• the fibers and the Ca(OH) 2 in the form of lime form a slurry less than or equal to 5% solids, preferably from 1 to 4% solids, most preferably from 1.5 to 2.5% solids.
• the % solids of the slurry may include 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0wt%, including any and all ranges and subranges therein.
• the fibers, Ca(OH) 2 and/or CO 2 maybe contacted together at any pH.
• the pH is greater than or equal to 6, more preferably the pH may be from 6 to 12, most preferably from 8 to 10.5.
• the pH maybe l, 2, 3, 4, 5, 6, 7, 7.5, 8, 8.5, 8, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, and 14, including any and all ranges and subranges therein.
• the fibers, Ca(OH) 2 and/or CO 2 may be contacted together in any manner.
• the contacting occurs in at least one reactor.
• reactors include a tubular reactor, a tank reactor, a continuous stirring tank reactor (CSTR), a continuous tubular reactor, and/or plug flow reactor.
• CSTR continuous stirring tank reactor
• plug flow reactor Preferably, a tubular (plug flow) reactor and/or a series of continuous stirring tank reactors are utilized.
• reaction conditions may be such so as to promote the fiber and the filler engaged in either a chemical and/or physical interaction.
• the method of making the fiber filler complex may be added to any conventional papermaking process.
• Methods and apparatuses for making paper substrates and paper-related materials are well known in the paper and paperboard art. See for example, G.A. Smook referenced above and references cited therein all of which is hereby incorporated by reference. All such known papermaking methods can be used in the practice of this invention and will not be described in detail.
• the fiber filler complex may be added to the process in a manner that replaced entirely and/or in part the conventional fibers utilized.
• the fiber filler complex may be added to the papermaking process in any concentration and/or amount that is desired in order to obtain the desired retention of the fiber filler complex in the paper substrate made therefrom.
• the fiber filler complex may be contacted with the paper substrate at any point in the papermaking process.
• the contacting may occur anytime in the papermaking process including, but not limited to the thick stock, thin stock, head box, size press, water box, and coater. Further addition points include machine chest, stuff box, and suction of the fan pump.
• the paper substrate of the present invention may also include optional substances including pigments, dyes, optical brightening agents, fillers not in the form of a fiber-filler complex, retention aids, sizing agents (e.g. AKD and ASA), binders, thickeners, and preservatives.
• optional substances including pigments, dyes, optical brightening agents, fillers not in the form of a fiber-filler complex, retention aids, sizing agents (e.g. AKD and ASA), binders, thickeners, and preservatives.
• binders include, but are not limited to, polyvinyl alcohol, Amres (a Kymene type), Bayer Parez, polychloride emulsion, modified starch such as hydroxyethyl starch, starch, polyacrylamide, modified polyacrylamide, polyol, polyol carbonyl adduct, ethanedial/polyol condensate, polyamide, epichlorohydrin, glyoxal, glyoxal urea, ethanedial, aliphatic polyisocyanate, isocyanate, 1,6 hexamethylene diisocyanate, diisocyanate, polyisocyanate, polyester, polyester resin, polyacrylate, polyacrylate resin, acrylate, and methacrylate.
• optional substances include, but are not limited to silicas such as colloids and/or sols.
• silicas include, but are not limited to, sodium silicate and/or borosilicates.
• solvents including but not limited to water.
• the paper substrate of the present invention may contain retention aids selected from the group consisting of coagulation agents, flocculation agents, and entrapment agents dispersed within the bulk and porosity enhancing additives cellulosic fibers.
• the paper substrate of the present invention may contain from 0.001 to 50 wt% of the optional substances based on the total weight of the substrate, preferably from 0.01 to 10 wt %, most preferably 0.1 to 5.0wt%, of each of at least one of the optional substances.
• This range includes 0.001, 0.002, 0.005, 0.006, 0.008, 0.01, 0,02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 25, 30, 35, 40, 45 and 50wt% based on the total weight of the substrate, including any and all ranges and subranges therein.
• the optional substances may be dispersed throughout the cross section of the paper substrate or may be more concentrated within the interior of the cross section of the paper substrate. Further, other optional substances such as binders for example may be concentrated more highly towards the outer surfaces of the cross section of the paper substrate.
• the paper substrate of the present invention may also contain a surface sizing agent such as starch and/or modified and/or functional equivalents thereof at a wt% of from 0.05wt% to 50wt%, preferably from 5 to 15 wt% based on the total weight of the substrate.
• the wt% of starch contained by the substrate may be 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 25, 30, 35, 40, 45 and 20wt% based on the total weight of the substrate, including any and all ranges and subranges therein.
• modified starches include, for example, oxidized, cationic, ethylated, hydroethoxylated, etc.
• functional equivalents are, but not limited to, polyvinyl alcohol, polyvinylamine, alginate, carboxymethyl cellulose, etc.
• the paper substrate may be pressed in a press section containing one or more nips.
• any pressing means commonly known in the art of papermaking may be utilized.
• the nips may be, but is not limited to, single felted, double felted, roll, and extended nip in the presses.
• any nip commonly known in the art of papermaking may be utilized.
• the paper substrate may be dried in a drying section. Any drying means commonly known in the art of papermaking may be utilized.
• the drying section may include and contain a
• drying can, cylinder drying, Condebelt drying, IR- or other drying means and mechanisms known in the art.
• the paper substrate maybe dried so as to contain any selected amount of water.
• the substrate is dried to contain less than or equal to 10% water.
• the paper substrate may be passed through a size press, where any sizing means commonly known in the art of papermaking is acceptable.
• the size press for example, may be a puddle mode size press (e.g. inclined, vertical, horizontal) or metered size press (e.g. blade metered, rod metered).
• sizing agents such as binders may be contacted with the substrate.
• these same sizing agents may be added at the wet end of the papermaking process as needed.
• the paper substrate may or may not be dried again according to the above-mentioned exemplified means and other commonly known drying means in the art of papermaking.
• the paper substrate maybe dried so as to contain any selected amount of water.
• the substrate is dried to contain less than or equal to 10% water.
• the paper substrate may be calendered by any commonly known calendaring means in the art of papermaking. More specifically, one could utilize, for example, wet stack calendering, dry stack calendering, steel nip calendaring, hot soft calendaring or extended nip calendering, etc. While not wishing to be bound by theory, it is thought that the presence of the expandable microspheres and/or composition and/or particle of the present invention may reduce and alleviate requirements for harsh calendaring means and environments for certain paper substrates,, dependent on the intended use thereof.
• the paper substrate may be microfinished according to any microfinishing means commonly known in the art of papermaking. Microfinishing is a means involving frictional processes to finish surfaces of the paper substrate.
• the paper substrate may be microfinished with or without a calendering means applied thereto consecutively and/or simultaneously. Examples of microfmishing means can be found in United States Published Patent Application 20040123966 and references cited therein, which are all hereby, in their entirety, herein incorporated by reference.
• Handsheet Set 1 contained SaveAll fiber fines with high surface area, while the other Handsheet Set 2 contained unrefined fibers.
• Figures 1 and 2 show a plot of the Sheffield smoothness, in Sheffield Units (SU), of the ID and NS sides, respectively, of the paper substrates versus the wt% ash Contained in that paper substrate. There is a smoother surface at equal ash content for the paper substrates containing the unrefined pulp than those paper substrates containing highly refined and/or recycled and/or SaveAll pulp at the same ash content.
• SU Sheffield Units
• a SaveAll fiber fine sample was collected from a mill stream and contained a fluorescence that contributed 46 CIE-Whiteness points.
• this sample was mixed with Ca(OH) 2 and then reacted with CO 2 to form CaCO 3 to form a fiber- CaCO 3 complex, the sample contributed 23 CIE-Whiteness points, a decrease of 23 CIE-Whiteness points.
• This decrease in residual OBA efficiency is attributable to quenching of the residual OBA in SaveAll pulp because of the pH increase to > 12 when the Ca(OH) 2 is added.
• the table of Figure 3 further demonstrates fluorescent data, as measured by CIE- Whiteness, SaveAll fiber fines pulp to the same pulp after forming a fiber- CaCO 3 complex.
• the addition of Ca(OH) 2 to the fibers caused the pH to increase above 12 and, as the data shows in Figure 3, caused the residual OBA to become less efficient.
• JEP-3 The goal of this study was to identify the best shape and size ('i.e., morphology) of the PCC to be attached in a fiber-filler complex in order to maximize bulk and sheet strength.
• SMI's 4G process was used to produce these samples, with the goal of producing fiber-filler complexes with the PCC component matching the new SMI "3G" products (e.g., Megaf ⁇ I-4000, UltraBulk-ll, Albacar-SP, etc.).
• Figure-4 summaries the physical test properties of the samples and compares them relative to the Saillat Megafil-2000 (aka, Megaf ⁇ l-S) control sample.
• the UltraBulk-ll composite had the best bulk and stiffness opportunity while also reducing the demand for AKD sizing and OBA, relative to Megafil-S.
• the "4G" process which involved pre-carbonating the PCC to > 90% conversion before adding fiber, very low attachments of the PCC to the fiber were observed with these samples (see Table-6).
• the attachment of the UltraBulk-ll composite was less than half that of the Carthago tube reactor sample.
• JEP-4 study began looking at ways to improve the attachment of the PCC to the fiber but most of the advances in this area were done in studies JEP 7-8, which were done in parallel with JEP-7 being done at SMRCs lab and JEP-8 being done in the Easton pilot plant.
• JEP-I The goal of JEP-7 was to explore process variables that impacted the attachment of PCC to fiber, not being concerned with morphology for the present.
• the samples of JEP-7 were produced using the IP tube located at SMI's Easton pilot plant and the results are summarized in Table-7 and Figure-5.
• Table-7 and Figure-5 various cubic-shaped products were obtained during this study. These large cubic PCC structures gave better sizing and OBA performance than the Megafil-S control used but also gave slightly lower opacity. The project team believes that this optical deficiency can be overcome with the targeted filler increase.
• two process changes were instituted to improve attachment and to try to guide morphology towards the large cubes. These changes are:
• V standard Saiiiat filler, is NOT a composite
• Table-7 Summary of JEP-7 products, showing % attachment, morphology characterization, and carbonating conditions. Note, even though no specific morphology was targeted, large cubic PCC often resulted from the process conditions used. • Furthermore, these large cubes were attached well to the fiber. Also in this study it was noted that pre-gassing (i.e., pre-carbonating) the fiber resulted in a greater tendency for large cubic PCC.
• JEP-8 I he goal of JEP-8, which was performed in parallel with JEP-7, was to improve upon the attachment of the UltraBulk-ll morphology identified in study JEP-3. This work was performed in SMRC using a lab CSTR reactor system. In this study, over fifty experiments were performed testing a range of parameters in an effort to obtain good attachment of the PCC to the fiber while still maintaining the UltraBulk-ll morphology identified in study JEP-3. Some of the parameters evaluated include: degree of pre- conversion of PCC before adding fiber, chemical additives, temperature, pressure, reactor type, fiber source, pre-gassing fiber, using various types of seed crystals, etc. In the end, it was concluded that:
• Fiber is needed to be present from the start of the reaction in order to achieve good attachment of PCC to the fiber. If the lime was pre-carbonated before adding fiber, it either resulted in poor morphology if the degree of pre-conversion was too low (e.g., ⁇ 50%) or resulted in poor attachment if the degree of pre-conversion was too high.
• TabIe-8 and Figure-6 summarize the products and specifications of the JEP-7 products.
• the handsheet performance of the JEP-7 cubic-samples was similar to the cubic samples from JEP-7, in being better performers in terms of AKD and OBA demand, poorer performers optically, and slightly better in bulk (1-3% better).
• TabIe-8 Summary of JEP-7 products, showing attachment and morphology of the fiber- filler complex, in addition to some process conditions used for its production.
• JEP-9 The objective of study JEP-9 was to confirm the performance of cubic fiber-filler composite structures in handsheet paper. The results of JEP-9 were presented to the IP-SMI Executive Committees and the Saillat mill in March 2004. Figure-7 shows the cubic structures from the JEP-9 study. The DSF handsheet results of the JEP-9 study am summarized in Figures 8-14.
• ranges are used as a short hand for describing each and every value that is within the range, including all subranges therein.

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