Patent Grant
8741104
This application is based on U.S. Provisional Application Ser. No. 61/518,047, entitled “Tissue Products with Nanoporous Fiber”, filed Apr. 29, 2011 and U.S. Provisional Application Ser. No. 61/628,698, entitled “Tissue Products Incorporating Nanoporous Cellulose Fiber”, filed Nov. 4, 2011. The priorities of U.S. Provisional Application Ser. Nos. 61/518,047 and 61/628,698 are hereby claimed and the disclosures are incorporated herein by reference in their entireties.
Even though cellulose is by far the most common naturally-occurring polymer, its extremely useful chains are often almost locked up by lignin, hemicelluloses and, particularly, adjacent chains of cellulose. Accordingly, even though there are numerous known methods of freeing cellulose molecules from their surroundings, these methods are typically rather expensive, involving high temperatures, long residence times and a variety of more or less troublesome chemicals. Recently, a method of increasing the accessibility of chains of cellulose has been developed as set forth in International Publication No. WO 2009/124240 A1 (International Application No. PCT/US2009/039445), entitled “H
In this novel form of cellulose, substantial crystallinity is retained by the cellulosic structure with the molecular chains remaining organized in a specific pattern, apparently maintaining the spatial relationship of the chain molecules aligned parallel to each other; but with significant internal disorder of the anhydroglucose units within individual chains. Thus after transformation to the novel form of cellulose, the internal organization of individual chains is less ordered than it is in the cellulosic source material but the molecular chains seem to retain their organization parallel to each other in a manner not unlike that prevailing in the source celluloses. Thus, as more fully described in U.S. Provisional Application No. 61/382,604, filed Sep. 14, 2010 and entitled “N
However, Atalla I and II are almost exclusively concerned with the chemical aspects of this rearrangement, being primarily directed in increasing the chemical accessibility of individual cellulose molecules for chemical reaction to facilitate production of ethanol from cellulose and other chemical reactions. What was previously unrecognized is that laterally expanded cellulose fibers are ideally suited for use in manufacture of towel and tissue products as relatively small amounts of LEC fiber can produce significant improvements in sheet properties, especially for soft tissue products—bath and facial tissue.
Laterally expanded cellulose fibers can make significant contributions to tissue properties in three areas that are of major concern to tissue makers: they can significantly increase bulk, reduce tensile and improve sheet porosity. Further, these fibers increase the freeness of the sheet making it possible to remove more water from the sheet mechanically. Tissue makers can use this advantage by increasing the speed of their machines as well as by savings in the amount of energy required for drying per ton of tissue dried. LEC fiber also integrates well into existing tissue making operations as the beneficial properties of LEC fiber are relatively insensitive to refining. In many tissue making operations, the strength of the tissue being manufactured is controlled by varying the amount of refining applied to the furnish. Since the effect of refining on LEC fiber is not extremely pronounced, the benefits obtained by including LEC fiber in the furnish are not necessarily excessively attenuated by the typical variations in refining used by the tissue maker to control strength and thereby control softness.
Laterally expanded cellulose fibers are also highly advantageous in fluff-pulp applications including diapers, catamenial devices and other absorptive applications, particularly because webs incorporating LEC fibers exhibit substantial recovery in bulk after pressing, do not require as much debonder to achieve good bulk and can be formed with less intensive defiberizing operations such as hammermilling. The ability to reduce or eliminate debonder is particularly significant as debonders are not only expensive, they inherently conflict with the absorptive web's raison d'être—absorption.
In Attala I, the laterally expanded cellulose is treated with enzymes converting the saccharides in the cellulose chains into glucose far more rapidly than previously known procedures for converting cellulose to ethanol. It appears that the treatment both opens up the fiber and decreases the crystallinity of the cellulose. As discussed herein, the presence of laterally expanded cellulose can be verified by staining with Graff's C-Stain, X-ray diffraction, Raman spectroscopy, high magnification microscopy and solid state NMR techniques. Even though laterally expanded cellulose is converted to glucose far more rapidly than previously known forms of cellulose, the process is not instantaneous. Laterally expanded cellulose fibers can be used after the alkalinity has been washed out; or, if desired, the residual fibers can be used after part of the cellulose has been enzymatically converted to glucose. In one example, approximately 60% of the cellulose was converted to glucose after 13 or so hours; but, after 28 more hours for a total of about 41 hours, only another 20% was converted. Accordingly, it may be more economically attractive in some cases to convert about 50% to 60% of the cellulose to glucose and use the remaining portion of the cellulosic fibers for papermaking, than to tie up equipment for an additional 28 hours to convert only an additional 20% of the cellulose to glucose. It can be appreciated that, as the enzymatic step will most likely be the bottleneck in any plant for conversion of cellulose to glucose, a plant converting approximately 50 to 60% of the cellulose to glucose and forwarding the remainder of the fibers to papermaking might produce more than twice as much glucose in a given period of time as a plant allowing the enzymatic reaction to proceed to the point at which over 80% of the cellulose had been converted.
LEC fibers can be distinguished from conventional cellulosic fibers by several methods even if the history of their manufacture is unknown:
Raman spectra for LEC fibers typically exhibit broad overlapping maxima in the range between 285 and 500 cm−1, often taking the form of two pairs of peaks, one centered near 367 (cm−1) and the other near 441 (cm−1) with the Raman intensity of the pair at 367 (cm−1) exceeding that of the pair at 441 (cm−1). In the region of Raman shifts between about 250 and 650 cm−1 which are often considered particularly useful in characterization of celluloses, the peaks are broadened and less distinct than the peaks in the same region for Cellulose I and Cellulose II. The discernible peaks near 489 and 578 cm−1, perhaps more properly called apiculi, can provide important points of differentiation between LEC and Celluloses I and II with the apiculus at 489 cm−1 being shifted about 5 cm−1 more than the corresponding apiculus of cellulose II which occurs at 484 cm−1 while the apiculus at 578 cm−1 is shifted about 12 cm−1 more than its counterpart in cellulose I.
Tables 1A and 1B set forth the Raman spectra obtained for both treated and untreated cellulose fibers obtained from a variety of cellulose sources.
Table 1C sets forth those peaks which show up most distinctly in and reliably in Raman spectra of treated fibers obtained from these fiber sources:
Table 1D sets forth the heights of the Raman peaks by which Nanoporous cellulose (laterally expanded cellulose) may be most readily distinguished from conventional cellulose.
Similarly the two peaks observed in the X-ray diffractogram for Cellulose I are broadened and merged relative to the X-ray diffractogram for Cellulose I prepared by the kraft process as shown in
LEC fibers in a formed web comprising conventional fibers can be identified by their ability to accept a deep blue stain similar to the Bright Blue Stain indicated for 20% on Plate IV at Bright Stain of Graff's Color Atlas when stained with Graff C-stain. Lignin containing fibers will stain in various hues of red, yellow and orange. Highly bleached sulfate pulps will accept more of a purple to dusky blue. See tiles in row 7 under S. W. Unblch. & Blch, Soda, Sodite & Kraft as well as tiles in rows 7 and 8 of H. W. Unblch. & Blch, Soda, Sodite & Kraft in plate III of “A C
LEC fibers formed into handsheets will exhibit a bulk at least about 50% greater than that of a handsheet made from untreated fiber; a tensile strength which is greatly reduced from that of a comparable handsheet, no more than about 70% of the tensile strength of comparable handsheet; and if made from unbeaten fibers, a porosity exceeding that of the comparable sheet by at least a factor of three; a caliper, void volume and liquid retention which is at least fifty percent greater than that of the cellulose I hand sheet, typically at least double. It appears that many of these benefits are at least in large part attributable to the anfractuous nature of the LEC fibers. Typically LEC fibers will exhibit a length weighted curl index of at least about 0.15 and often of at least about 0.2 as determined using known procedures set forth in Lee; M
The Raman spectra of LEC fibers will typically exhibit either:
The Raman spectra of more preferred LEC fibers will typically exhibit:
As compared to the fiber sources from which they are prepared, LEC fibers will exhibit three broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1; another being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 and the third being a peak centered near 1100 cm−1, at least two of said peaks being at least 10%, 15% or 20% broader at half height than the corresponding peak in the pulp from which it was prepared. Often at least one of said peaks is at least 100% broader at half height than the corresponding peak in the cellulosic from which it was prepared.
A preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ, preferably at least about 3.25° 2Θ, still more preferably from at least about 3.5° to about 7° 2Θ, most preferably from at least about 3.0° to about 7° 2Θ, the Raman spectrum of said nanoporous cellulose fibers in the region between 285 and 500 cm−1 exhibiting increased overlap and lowered maxima as compared to cellulose I and cellulose II.
An especially advantageous embodiment of the present invention is an absorbent pad for a diaper, catamenial device or panty liner comprising laterally expanded cellulosic fibers.
Another especially advantageous embodiment of the present invention is an absorbent cellulosic sheet comprising laterally expanded cellulosic fibers and conventional papermaking fibers, said conventional papermaking fibers being selected from the group consisting of bleached and unbleached Kraft wood pulp fibers, bleached and unbleached mechanically pulped fibers, chemically pulped hardwood and softwood fibers, recycled fibers, TMP, CTMP, BCTMP and mercerized fibers.
Another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fibers accepting a blue stain when treated with Graff C-stain, the stain exhibiting less red than the stains exhibited with bleached hardwood kraft fibers and bleached softwood kraft fibers; and exhibit broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, said broad overlapping maxima defining at least one doublet between 300 cm−1 and 500 cm−1.
Another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fibers exhibiting an X-Ray diffraction peak at 2Θ=20.6° having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ, preferably at least about 3.5°, for the most prominent reflection and exhibiting broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the width of the tallest of said maxima in said spectrum between 285 and 400 cm−1 being at least about 30 cm−1, preferably at least about 35, 40 or 45 cm−1, and the width of the tallest of said maxima in said spectrum between 400 and 500 cm−1 being at least about 55 cm−1, preferably at least about 60, 65, 70 or 90 cm−1.
Yet another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fibers, wherein the Raman Spectrum of the fibers exhibits two broad peaks, one centered near 367 cm−1 and another lower peak centered near 441 cm−1, the peak centered near 367 cm−1 having a width at half height of at least about 30 cm−1, the peak centered near 441 cm−1 having a width at half height of at least about 55 cm−1.
Yet another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 355 and 360 cm−1, the height of the peak between 355 and 360 cm−1 being at least 20%, preferably at least 25%, more preferably at least 30% and most preferably at least 34%, of the height of the peak between 1094 and 1098 cm−1.
Another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 416 and 423 cm−1, the height of the peak between 416 and 423 cm−1 being of the height of the peak between 1094 and 1098 cm−1.
Another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 487-493 cm−1, the height of the peak between 487 and 493 cm−1 being at least 25% of the height of the peak between 1094 and 1098 cm−1.
Yet another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between 895 and 901 cm−1, the height of the peak between 895 and 901 cm−1 being at least 25% of the height of the peak between 1094 and 1098 cm−1.
Still another preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between 1260 and 1267 cm−1, the height of the peak between 1260 and 1267 cm−1 being at least 10% of the height of the peak between 1094 and 1098 cm−1.
A greatly preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting peaks in its Raman spectrum between:
Another highly preferred embodiment of the fibrous cellulosic product of the present invention will comprise nanoporous cellulose fiber exhibiting at least a first and a second peak in its Raman spectrum, said first peak falling into a band between: about 348 and 360 cm−1, about 416 and 424 cm−1, about 487 and 493 cm−1, about 895 and 901 cm−1, about 1094 and 1098 cm−1, or about 1260 and 1267 cm−1; said second peak falling into one of said bands other than the band into which said first peak falls; wherein the height of said first peak relative to the height of the peak between 1094 and 1098 cm−1 is:
Another advantageous fibrous cellulosic product of the present invention comprises nanoporous cellulose fiber exhibiting a multiplicity of peaks falling into defined bands in its Raman spectrum including at least one peak between falling between 1094 cm−1 and 1098 cm−1, the height of each said peak relative to the height of said peak between 1094 cm−1 and 1098 cm−1 exceeding the minimum relative peak height for that band as set forth in the following table:
at least three peaks are present in the Raman spectrum, other than said one peak between falling 1094 cm−1 and 1098 cm−1; falling into one of said defined bands and exceeding the Minimum Relative Peak Height specified for that defined band; preferably at least four, more preferably at least 5, of the peaks in the Raman spectrum of said cellulosic tissue product both fall into one of said defined bands and exceed the minimum relative peak height for the band into which it falls.
Often preferred embodiments of the present invention will be identifiable by doublets in their Raman spectrum. Often such doublets will be found at the following locations:
Many preferred embodiments of the present invention will be identifiable by the presence of multiple doublets in their Raman spectrum as follows:
In a particularly preferred fibrous cellulosic product comprising nanoporous cellulose fibers, the nanoporous cellulose fibers exhibit at least two broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 55% of the height of the peak near 1098 cm−1.
In a particularly preferred fibrous cellulosic product comprising nanoporous cellulose fibers, the nanoporous cellulose fibers exhibit at least three broad peaks in their Raman spectrum, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1; another being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 and the third being a peak centered near 1098 cm−1, at least two of said peaks being at least 10% broader at half height than the corresponding peak in the pulp from which it was prepared, preferably at least two of said peaks are at least 15%, more preferably at least 20%, broader at half height than the corresponding peak in the pulp from which it was prepared. Often it will be observed that at least one of said peaks is at least 100% broader at half height than the corresponding peak in the pulp from which it was prepared.
In almost all cases, the peak widths of the nano-porous cellulosic fibers of the present invention will be considerably broader than the corresponding peaks of the fibers from which they were prepared. In many cases, the Raman Spectrum of the nanoporous fibers exhibit two broad peaks, one being a series of overlapping peaks between about 250 cm−1 to about 400 cm−1; and the other being a series of overlapping peaks between about 400 cm−1 to about 600 cm−1, each said peak being at least 10%, preferably at least 15%, more preferably at least 20%, broader at half height than the corresponding peak in the cellulosic fiber from which it was prepared. Ideally at least one of said peaks is at least 100% broader at half height than the corresponding peak in the pulp from which it was prepared.
A particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers, the Raman Spectrum of said nanoporous fibers exhibiting three broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibiting a width at half height of at least about 30 cm−1, preferably at least about 35 cm−1; another being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 55 cm−1 and the third being a peak centered near 1098 cm−1 exhibiting a width at half height of at least about 46 cm−1, preferably at least about 55 cm−1.
Another particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a series of overlapping peaks between about 250 cm−1 and about 400 cm−1 having a width at half height of at least about 40 cm−1; along with a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 60 cm−1, preferably at least about 70 cm−1, and a peak centered near 1098 cm−1 exhibits a width at half height of at least about 50 cm−1.
Another particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a Raman Spectrum having two broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibiting a width at half height of at least about 30 cm—1, preferably at least about 35 cm−1, more preferably at least about 40 cm−1, still more preferably at least about 45 cm−1, most preferably at least about 50 cm−1, and the other being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 55 cm−1, preferably at least about 60 cm−1, more preferably at least about 75 cm−1 and most preferably at least about 90 cm−1.
Yet another particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a Raman Spectrum having peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1 with:
Still another particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a Raman Spectrum having peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1, with:
Many particularly preferred fibrous cellulosic products comprise nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a Raman Spectrum having peaks near 458, 1098, and 1600 cm−1, with:
A particularly preferred fibrous cellulosic product comprises nanoporous cellulose fibers prepared from wood pulp fibers exhibiting a Raman Spectrum having peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1 and exhibiting:
When examined at high magnification using ESEM (Environmental Scanning Electron Microscopy), the nanoporous fibers used in the present invention may be identified by large numbers of dark regions on the fibers having diameters between about 0.1 and 10 microns, preferably between about 0.5 and 7 microns and most preferably between about 1 and 5 microns. Preferably, these dark regions are present in a range of at least about 108 regions per square meter, preferably between about 5×108 to about 1013 regions per square meter, more preferably between about 109 to 1012, and most preferably between about 1010 to 1011 regions per square meter of fiber. It is not known at this time whether these are only darkened regions or if they are pits penetrating into the fiber. However, it is known that these darkened regions are not apparent on untreated or conventional fibers but may be readily observed on the treated fibers having the desirable properties described herein. Despite the use of the term “diameter”, it can be observed that these regions are not perfect circles but are only roughly circular in shape.
The treatment process for preparation of LEC is described in WO2009124240, Highly Disordered Cellulose, (Atalla I), the entirety of which is incorporated herein by reference. In Atalla I, cellulose is treated with an alkali and an alcohol/water co-solvent system. Cellulose so treated shows dramatically less crystallinity than normal Kraft pulp, which makes this treatment ideal for subsequent enzymatic treatment to convert the cellulose to glucose. Cellulose chains in the fibers appear to be much more accessible after this treatment. Given this increased accessibility, it was hypothesized that this fiber might exhibit much less bonding and more bulk than an untreated fiber. However, fibers treated according to Atalla I still retain substantial crystallinity particularly along the length of the cellulosic chains, it appears that the primary effect of treatment according to Atalla I is to relax the bonds between adjacent chains thereby making the cellulose therein more accessible while greatly weakening the bonds between adjacent cellulosic chains. Fiber so treated is neither amorphous nor mercerized nor completely disordered but is, rather, nanoporous or laterally expanded.
LEC fibers can be incorporated into tissue sheets made by any known process, including conventional wet pressing (“CWP”), through-air drying using a Yankee dryer (“TAD”), through air drying in which the sheet is dried on the fabric rather than being creped from a Yankee (“UCTAD”) as well as methods in which a web at between about 30% and about 60% consistency is creped from a transfer cylinder using either a woven creping fabric or a perforate polymeric belt and thereafter dried in any convenient manner. Other new papermaking techniques recently developed for manufacture of tissue products can be used as well. The LEC fiber can be incorporated into the sheet homogeneously or layered into the exterior layers as would any other papermaking fiber. In cases where the anfractuous nature of the fibers conflicts with obtaining the desired degree of formation, well known foam forming techniques can be used to considerable advantage. Alternatively, well known associative thickener technology can be used as well to address formation issues thought to be attributable to the anfractuous nature of the fibers. Conventional papermaking chemicals can be used as well known by those having skill in the art. Conventional converting procedures can be used for transforming basesheets into finished salable products.
Conventional cellulosic fibers include any fiber typically used for papermaking having cellulose as a major constituent except those fibers described herein as laterally expanded cellulosic fibers or nanoporous cellulose. Conventional cellulosic fibers thus include cellulosic fibers prepared from virgin pulps or recycle (secondary) cellulosic fibers. Conventional cellulosic fibers include: nonwood fibers, such as cotton fibers, cotton linters, or cotton derivatives, abaca, kenaf, sabai grass, flax, esparto grass, straw, jute hemp, bagasse, milkweed floss fibers, corn stover, rice straw and pineapple leaf fibers; and wood fibers such as those obtained from deciduous and coniferous trees, including softwood fibers, such as northern and southern softwood kraft fibers; hardwood fibers, such as eucalyptus, maple, birch, aspen, or the like. Conventional cellulosic fibers can be liberated from their source material by any one of a number of chemical pulping processes familiar to one experienced in the art including sulfate, sulfite, polysulfide, soda pulping, etc and may be bleached, if desired, by chemical means including the use of chlorine, chlorine dioxide, oxygen, alkaline peroxide and so forth. Conventional fibers (whether derived from virgin pulp or recycle sources) also include mechanical or high yield fibers including groundwood, fibers prepared from thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP) pressure/pressure thermomechanical pulp (PTMP), and alkaline peroxide mechanical pulp (APMP), neutral semi-chemical sulfite pulp (NSCS), high coarseness lignin-rich fibers, such as bleached chemical thermomechanical pulp (BCTMP), may, for example, be derived from a plant selected from the group consisting of: wood, cotton, flax, sisal, abaca, hemp, hesperaloe, jute, bamboo, bagasse, kudzu, corn, sorghum, gourd, agave, loofah and mixtures thereof. Conventional cellulosic fibers included wood pulp fibers which may be short (typical of hardwood fibers) or long (typical of softwood fibers). Nonlimiting examples of short fibers include fibers derived from a fiber source selected from the group consisting of Acacia, Eucalyptus, Maple, Oak, Aspen, Birch, Cottonwood, Alder, Ash, Chemy, Elm, Hickory, Poplar, Gum, Walnut, Locust, Sycamore, Beech, Catalpa, Sassafras, Gmelina, Albizia, Anthocephalus, and Magnolia. Nonlimiting examples of long fibers include fibers derived from Pine, Spruce, Fir, Tamarack, Hemlock, Cypress, and Cedar. Softwood fibers derived from the kraft process and originating from more-northern climates may be preferred. These are often referred to as northern softwood kraft (NSK) pulps. For the purposes of this application, mercerized fibers prepared from any of the preceding sources should also be considered conventional cellulosic fibers.
We found that addition of LEC fibers to otherwise conventional papermaking blends makes it possible for the papermaker to obtain great improvements in bulk, porosity, and opacity as well as novel tactile properties. It can be appreciated that not only do LEC fibers impart remarkable improvements in properties to standard TAPPI handsheets, they also respond more favorably to refining as demonstrated by TAPPI standard Valley Beater curves.
To demonstrate these points, a Northern Softwood Kraft (NSWK) was chosen as a premium fiber used in all types of papermaking, including tissue and towel production. The findings of this work can be summarized as follows:
More specifically, results set forth herein indicate that:
Currently, few high end premium consumer products are made with large amounts of recycled fiber. Applying the Atalla I treatment to form LEC fibers from recycle grades as described herein offers the potential to dramatically improve the tactile properties of recycled furnishes without the usual reduction in yield typically resulting from conventional processing of the raw waste paper to improve the quality thereof.
Non-woody fibers are often suggested for papermaking but tend to be slow draining furnishes that produce thin, noisy, sheets. Subjecting these fibers to the Atalla I process can significantly improve their properties for papermaking Rather than densifying the sheets, these treated non-woody fibers can open up the sheet and reduce the bonding potential.
The Atalla I process can be used to reduce the environmental impact of many agricultural operations. For example in many cases, rice straw is burned or buried to prepare the ground for the next crop. Instead, this straw could be used to produce a highly desirable papermaking fiber along with useful amounts of glucose if so desired. Similarly, fibers which are currently viewed as having very little value, such as those derived from corn stover, switchgrass, miscanthus, and lawn and tree maintenance byproducts can be utilized to produce glucose, papermaking fiber, glucose with papermaking fiber as a by-product or papermaking fiber with glucose as a by-product.
Since the Atalla I process apparently decreases the inter-chain bonding between the cellulosic chains in LEC fibers, it appears that, when LEC fibers are incorporated into blends of conventional papermaking fibers, these treated fibers create a debonding and bulk building effect on otherwise standard fiber blends, improving drying efficiency both through better air flow through the sheet as well as by starting with a dryer sheet, resulting in increased removal of water through mechanical pressing and in softer, thicker sheets.
Over a period of 5-15 minutes, NSWK pulp was treated with a 75/25 ratio of ethanol/water into which was dissolved 7% NaOH over a period of 5-15 minutes. Following this soaking, the fibers were washed two times with a 75/25 mix of ethanol and water to substantially remove all of the NaOH. The fibers were then washed with water to remove the remaining ethanol and dried. These dried fibers were then re-slurried and used to produce handsheets in the desired fiber blend ratios. A more detailed description of this Atalla I process can be found in the WO2009124240 patent application, incorporated herein by reference.
Accordingly, a series of trials was conducted to more fully and precisely define the properties of LEC fibers. A great deal of care was taken to insure that fiber mixing was as uniform as possible. The blends of fibers were diluted to a set consistency and allowed to soak overnight. These blends were then mixed for about 3 minutes. Samples for the beater curves were then taken and the remaining fiber put through the British Disintegrator. Freeness was measured and, based upon the determined consistency, the volume of the solution needed for each handsheet was determined.
Effects of blending and refining NSWK fiber with LEC fiber derived from NSWK fiber were investigated using TAPPI Valley Beater runs and TAPPI standard T 205 sp-95 handsheet preparation and testing. Beating times of 0, 5, 15, 30, 45 and 60 minutes were studied over blends of 0, 25, 50, 75 and 100 percent LEC fiber blended with untreated NSWK. Handsheets were pressed and dried in rings and tested in a controlled environment testing laboratory. Unrefined blends of 5, 10, 15 and 20 percent LEC fibers were investigated to determine the sensitivity at lower addition rates. The handsheets prepared were tested according to TAPPI Standard T 220 sp-96.
A series of Valley Beater curves was run on 100% NSWK and 100% NSWK LEC fibers as well as on blends of 25/75, 50/50, and 75/25 blends of NSWK/NSWK LEC fibers, at beating times of 0, 5, 15, 30, 45, and 60 minutes. In addition to the handsheets made for these beater runs, handsheets were also made from unrefined blends of these fibers at 5, 10, 15 and 20 percent LEC treated fibers.
An X-ray diffractogram was obtained of treated LEC fibers as set forth in
In passing, it should be mentioned that on the Raman spectra presented herein as well as those in “Atalla II”, U.S. Provisional Application No. 61/382,604, filed Sep. 14, 2010 and entitled “NANOPOROUS CELLULOSE”, which provides priority to U.S. application Ser. No. 13/822,190 published as U.S. Application Publication No. 2013/0172544, the far left hand line does not represent 0 Raman shift as the intensity of the spectrum at 0 is far too intense to be easily and meaningfully represented graphically with the remainder of the spectrum. The index markings on the spectra should accordingly be used in connection with the derivable scale to determine the locations and widths of the various peaks. Further, the Raman spectra presented herein were baseline corrected using known techniques often at least partially integrated into the software for the Spectrometers requiring the analyst to indicate baseline regions on the spectra.
Discussion of Results
First Series of Trials
While these responses are significant, for such fiber to be commercially successful, it is very important to understand the behavior at the lower end of the addition curve for the cost/benefit ratio at each addition level. Clearly, there is considerable variability exhibited in each of these properties especially at the lower addition levels. Further, a careful visual analysis of the sheets made during this preliminary or exploratory run showed non-uniformities in the fiber mixing and formation of the handsheets.
Second Series of Trials
The second round of trials was carefully planned to eliminate the mixing and uniformity problems as seen with the exploratory set of handsheets. Throughout the runs, TAPPI standard methods were utilized for mixing the fibers, and for preparing and making the handsheets. It was decided that to better understand the behavior of these fibers, standard beater curves would be run on a range of blends from 100 percent NSWK to 100 percent treated NSWK fibers in intervals of 25 percent. In addition, sheets made with unrefined blends were produced to detail the lower end of the blending ratios, namely 5, 10, 15 and 20 percent treated fibers
Therefore, while the preliminary or exploratory set of data produced directionally suggestive results providing an initial indication of the benefits attainable with LEC fibers, our analyses and conclusions about the properties these treated fibers impart to sheets and the economic benefits seen from using these fibers will be based solely on the second set of trials.
Refining Responses
Treated and untreated fibers and blends responded to the beating action in the Valley beater. Beating times of 0, 5, 15, 30, 45, and 60 minutes were used.
It appears that even highly refined LEC fiber will significantly reduce tensile and improve formation. For example, going from 100% NSWK to 100% LEC treated at the maximum refining levels, tensile can be seen to drop from 0.11 to about 0.07 (a 37% drop) while freeness rises from about 250 ml to about 450 ml. These are considered very significant changes. Another way to look at
LEC fibers add to the caliper of the sheets in a manner that is approximately opposite the shape of the tensile curve. As LEC fibers are added, sheet bulk and freeness are increased while tensile strength is decreased—regardless of the refining level at least within the limits tested.
Sheet porosity is also strongly affected by the addition of the LEC fibers. In
In many paper grades, opacity is a very important property.
Other sheet properties, stretch, TEA, burst, and tear, were measured on handsheets made with refined fiber. Even though the response of LEC fibers to refining varies significantly from behavior of conventional fibers, in most other regards, it appears that LEC fibers behave similarly to conventional fibers while providing the enhanced sheet properties discussed herein.
Unrefined Blends
When blended with unrefined NSWK fibers, unrefined LEC fibers act as debonding fibers in a very linear fashion for strength and bulk properties.
Unrefined NSWK fibers are relatively debonded compared with heavily refined fibers as is shown in
An even more valuable property of LEC fibers either refined or not, is their ability to significantly open up the sheet to increase the porosity as measured using the Gurley Method as explained in TAPPI T 460 and TAPPI T 536 for low and high air resistance respectively in which the time required to pass a given volume of air is measured and reported in seconds. As shown in
As is shown in Table 2, adding 25% LEC treated fibers to unrefined NSWK fibers increases the air flow rate to such an extent that the time required to pass a given quantity decreases by 59 percent. Reductions of this magnitude essentially mean that the air flow rate has more than doubled. When the NSWK and the LEC treated fibers are refined together, increased air flow persists, remaining relatively constant even at higher refining levels. Therefore, it should be expected that adding unrefined LEC fibers to a refined NSWK fiber might increase porosity by at least this much and, very likely, significantly more. Even if less than 25% unrefined LEC treated fiber is used, its use would likely produce a drop of about this amount. Accordingly, the fibers of the present invention are particularly advantageous for use in through air dried grades of towel and tissue products as a particularly large portion of the expense of manufacturing through air dried grades stems from the cost of removal of water therefrom by evaporation. Due to the improved spring back of the fibers of the present invention as well as the more uniform pore structure and higher porosity of sheets including these fibers, it will be possible to remove more water mechanically from the sheet while preserving its open structure, thereby greatly decreasing the amount of energy required for drying of the sheets and increasing the operating speed of the papermachine thereby making it possible to produce relatively more paper for the given size of the papermachine. Preferably, a furnish used for making through air dried grades will comprise at least about 1% by weight of nanoporous cellulose fibers, preferably at least about 3%, more preferably at least about 4% and most preferably between about 5 and about 25% by weight of nanoporous cellulose fibers.
In the Examples provided, LEC fibers and the conventional cellulosic papermaking fibers were blended before the refining step. To investigate the possibilities of using split stock refining systems, similar trials were conducted in which the LEC fibers were not refined but were blended with conventional papermaking fibers which had been previously refined to varying degrees. The results of these trials are set forth in Appendix I, parts 1 and 2. These results establish that LEC fibers behave far differently from either conventional papermaking fibers or mercerized cellulosic fibers and provide the papermaker with opportunities to improve both product performance and the productivity of his papermachine with significantly reduced costs for fiber.
Wet Pressing
While all handsheets tested were pressed to the same degree, the resultant tensile varied greatly with amounts of LEC fiber. These treated fibers appear to act like springs and expand back to larger sizes after pressing. In pressure controlled grades like tissue and towel, higher peak pressures result in dryer sheets after pressing. In pressure controlled nips, especially in machines where shoe presses are used, very high peak pressures can be combined with very sharp pressure release curves to greatly increase sheet dryness. An example of where this potential could be realized is a wet pressed, crescent former, tissue and towel machine of 300 inches of sheet width on the Yankee Dryer. This extreme width requires a very large diameter pressure roll to maintain the proper full width stiffness. Large diameters increase the width of the press nip and lower the average pressure in the nip. Reduced pressure results in lower post pressure roll consistency (PPRC) on the Yankee dryer. In this case, a typical PPRC might be expected to fall in about the 38-39 percent range. Incorporating LEC fibers into the furnish can make it possible to replace the pressure roll with a narrow shoe, shoe press which could realistically increase the dryness values to the 44-45 percent range without exceeding the 500 lbs/lineal inch (PLI) loading on the Yankee dryer. Moving from 38 percent to 45 percent dryness reduces the drying load from 1.6 lbs of water per lb of fiber down to 1.2 lbs/lb: a reduction of about 25 percent. It is possible that this is a conservative estimate of the savings potential since tissue and towel machines utilizing a shoe press routinely run to consistencies as high as 54 percent consistency after pressing.
However, using a shoe press alone does not automatically result in drying energy savings. A wet pressed tissue and towel machine utilizing a fabric creping step usually does not press to maximum dryness as this higher pressing can result in sheets that are too dense, too strong, and do not react to the subsequent creping steps in a way that yields the desired softness and absorbency for the grades being produced. But, when LEC is added to the furnish in such a machine, making the nascent web resistant to pressing, the tensile and density of the sheets can be controlled along with the high pressing to maintain and/or improve sheet properties while taking advantage of the much reduced drying costs. Adding these fibers to a 300 inch machine could allow the PPRC to reach or exceed 50 percent consistency while allowing the sheet to be adequately creped to produce the desired sheet properties. At a 50 percent PPRC, the drying costs would be further reduced from 1.2 lbs/lb down to just 1 lb/lb. Overall this consistency increase would reduce the drying load by about 37 percent—an amount which would be considered very significant even if only a small fraction of it were actually attained.
In response to environmental concerns, many urge that only recycled fibers should be used in tissue and towels or like paper grades that cannot be recycled. However, many consumers consider that recycle only grades exhibit a harsh feeling with low absorbency while sheets made from furnishes containing large amounts of recycled fibers can be similarly harsh and non-absorbent as well, depending on the amount of recycle fiber included. In general, this harshness may stem from the fact that most recycled fibers have been highly refined and contain large percentages of fines. Highly refined fibers are very conformable and therefore often form denser sheets than stiffer, less conformable, virgin fibers. In addition, fines can serve as a kind of “glue” often causing sheets to end up being very dense. In many cases, this density can prevent the creping process from opening these sheets up to get desired tactile properties. Treating a portion of the recycled fiber stream with the Atalla I process can produce sheets that are significantly less dense and easier to crepe making it possible to use very high amounts of recycled fibers in grades that are suitable both for the higher end of the commercial (away from home) market as well as in the consumer or retail market.
Heavier weight, flow controlled grades require both pressure and time control to get maximum water removal without “crush” sometimes referred to as sheet crushing or calendar crushing or calendar blackening—a formation disruption caused by fibers moving around in the press nip, thought to often be due to flowing water. Adding LEC fibers to these crush sensitive grades can provide a twofold advantage. First, these LEC fibers allow higher pressing levels without loss of bulk as a result of these higher loads. Secondly, as the data in Table 3 show, these treated fibers greatly increase the porosity of the sheets, thereby reducing the possibility of sheet crush in the press nip. These two effects potentially allow a paper maker to reduce drying load without sacrificing sheet formation or bulk.
When examined at high magnification using ESEM, the nanoporous fibers used in the present invention may be identified by large numbers of dark regions on the fibers having diameters between about 0.1 and 10 microns, preferably between about 0.5 and 7 microns and most preferably between about 1 and 5 microns; see
Non-Woody Fibers
Fibers from sugar cane (bagasse), rice, wheat, and others, are often used in various grades of paper even though they are largely available on a seasonal basis. However, these fibers, while low in cost, are mostly shorter and finer than woody fibers; and, accordingly, sheets produced from them tend to have higher density, lower opacity, strength and noisiness. Therefore, especially considering the seasonality of availability, these fibers are at a competitive disadvantage as the sheets produced from them are not usually considered all that desirable. However, treating these fibers with the Atalla I process can significantly improve their performance in paper grades, transforming these less desirable fibers into bulky, debonding fibers that can greatly change the properties of sheets made with them. Such uses could help alleviate fiber shortages.
Environmental Concerns
Rice is one of the major food crops of the world. The process of rice production requires the removal of the straw from the fields prior to the planting of the next crop. Today in most of the world, that removal is accomplished by burning, which adds to air pollution. In California, laws require that this straw be landfilled rather than burned. Therefore, converting this unwanted straw into a desirable paper making fiber could reduce the fiber shortages experienced in growing nations, while improving air quality, conserving landfill space and providing another source of income for farmers growing these crops.
Low grades fibers such as those derived from recycle sources appear to be greatly improved by converting a portion of the cellulose fibers therein to laterally expanded cellulose.
Southern pine kraft was treated as in Example 1 and the Raman spectrum therefor was measured. The results comparing treated to untreated pulp are shown in
Northern Hardwood Kraft was treated as in Example 1, and the Raman spectrum therefor was measured. The results comparing treated to untreated pulp are shown in
Avicel crystalline cellulose was treated as in Example 1, and the Raman spectrum therefor was measured. The results comparing treated Avicel to Cellulose I and Cellulose II are shown in
Northern Bleached Softwood Kraft was treated as in Example 1, and the Raman spectrum therefor was measured. The results comparing treated to untreated pulp are shown in
Table 4 below compares the width at half height of characteristic bands in these spectra. It can be appreciated that, in general but with some exceptions, the effect of treatment is to widen the characteristic bands by merging the peaks therein relative to the untreated fiber source.
Corn Stover was treated as in Example 1, and the Raman spectrum therefor was measured. The results comparing treated to untreated stover and ferulic acid are shown in
Table 5 presents the locations of the characteristic peaks in the Raman spectra of the nanoporous cellulose fibers treated herein while Table 5A presents the widths of the characteristic peaks at half height with overlapping peaks being counted as one peak when the spectrum remains above half the height of the tallest peak throughout.
For these samples, it can be observed that:
In contrast, it can be appreciated that, in the untreated cellulose samples:
None of these untreated celluloses exhibit adjacent peaks in this area with a peak to peak ratio of less than 1.25 and a peak to valley ratio of less than 1.25, while each of these treated celluloses had at least one pair of adjacent peaks with a peak to peak ratio of less than 1.1 and a peak to valley ratio of less than 1.25.
A variety of embodiments are considered extremely useful as summarized hereinbelow:
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ, said laterally expanded cellulose fibers exhibiting broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 50% of the height of the peak near 1098 cm−1.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 15% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ.
A wet-laid cellulosic tissue product of any preceding embodiment comprising at least about 10% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of from at least about 3.5° to about 7° 2Θ.
A wet-laid cellulosic tissue product of any preceding embodiment comprising at least about 20% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak at 2Θ=20.6° for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.5° to about 7° 2Θ.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said fibers accepting a blue stain when treated with Graff C-stain, said stain exhibiting less red than the stains exhibited with bleached hardwood kraft fibers and bleached softwood kraft fibers.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and at least about 15% of laterally expanded cellulose fibers, said fibers accepting a blue stain when treated with Graff C-stain and exhibiting broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 50% of the height of the peak near 1098 cm−1.
A wet-laid cellulosic tissue product of any preceding embodiment comprising conventional cellulosic fibers and at least about 10% of laterally expanded cellulose fibers, said fibers accepting a deep blue stain when treated with Graff C-stain.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and at least about 20% of laterally expanded cellulose fibers, said fibers accepting a deep blue stain when treated with Graff C-stain.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said fibers exhibiting an X-Ray diffraction peak at 2Θ=20.6° for the most prominent reflection and exhibiting broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 50% of the height of the peak near 1098 cm−1.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and at least about 15% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and at least about 20% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0°.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and at least about 25% of laterally expanded cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.5°.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, the Raman Spectrum of said fibers two broad peaks, one centered near 367 cm−1 and another lower peak centered near 441 cm−1, along with a peak near 898 cm−1 which relative to the tallest peak in the spectrum is shorter than the corresponding peak in Cellulose I but taller than the corresponding peak in Cellulose II.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting peaks in their Raman spectrum near 355 cm−1, 380 cm−1, 424 cm−1, 898 cm−1, 1098 cm−1, and 1372 cm−1, accompanied by apiculi at 489 cm−1, 578 cm−1, 1263 cm−1, and 1461 cm−1;
A wet-laid cellulosic tissue product of any preceding embodiment, comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers exhibiting the X-ray diffraction pattern set forth in
A wet-laid cellulosic tissue product of any preceding embodiment exhibiting the Raman spectrum set forth in
A wet-laid tissue product of any preceding embodiment wherein the cellulose in the LEC fibers comprises crystalline chains of cellulose molecules, the transverse spacing between the crystalline chains exceeding that found in crystals of cellulose I, while the crystalline chains retain the spatial relationship of the chain molecules relative to each other as found in the source cellulose from which the LEC fibers were derived.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting doublets centered near 367 cm−1 and 441 cm−1 in their Raman spectrum.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting apiculi in their Raman spectrum near: 489 cm−1 and 578 cm−1 as well as doublets centered near 367 cm−1 and 441 cm−1,
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting peaks in their Raman spectrum near: 489 cm−1 and 578 cm−1 as well as doublets centered near 367 cm−1 and 441 cm−1,
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting apiculi in their Raman spectrum near: 489 cm−1 and 578 cm−1 as well as doublets centered near 370 cm−1 and 445 cm−1,
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting peaks in their Raman spectrum near: 489 cm−1 and 578 cm−1 as well as overlapping peaks centered near 367 cm−1 and 441 cm−1,
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting apiculi in their Raman spectrum near: 489 cm−1 and 578 cm−1 as well as doublets centered near 367 cm−1 and 441 cm−1,
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting doublets centered near 367 cm−1 and 441 cm−1 in their Raman spectrum, the maximum of said spectrum in said region being less than 50% of the maximum near 1098 cm−1.
A wet-laid cellulosic tissue product comprising conventional cellulosic fibers and at least about 5% of laterally expanded cellulose fibers, said laterally expanded cellulose fibers exhibiting at least two broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 50% of the height of the peak near 1098 cm−1.
A wet-laid cellulosic tissue product as described in any previous embodiment, comprising conventional cellulosic fibers and fibers exhibiting the X-ray diffraction pattern set forth in
A wet-laid cellulosic tissue product of any preceding embodiment comprising conventional cellulosic fibers and fibers exhibiting the Raman spectrum set forth in
A wet-laid tissue product of any preceding embodiment wherein the cellulose in the LEC fibers comprises crystalline chains of cellulose molecules, the transverse spacing between the crystalline chains exceeding that found in crystals of cellulose I, while the crystalline chains retain the spatial relationship of the chain molecules relative to each other as found in the source cellulose from which the LEC fibers were derived.
A method of preparing a cellulosic tissue product comprising the steps of: forming laterally expanded cellulose fibers from lignocellulosic materials; blending said laterally expanded cellulosic fibers with conventional papermaking fibers; and forming a wet laid web therefrom; said laterally expanded cellulosic fibers exhibiting the X-ray diffraction pattern set forth in
A method of preparing a cellulosic tissue product comprising the steps of: forming laterally expanded cellulose fibers from lignocellulosic materials; blending said laterally expanded cellulosic fibers with conventional papermaking fibers; and forming a wet laid web therefrom; said laterally expanded cellulosic fibers exhibiting the Raman spectrum substantially the same as that set forth in
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ, the Raman spectrum of said nanoporous cellulose fibers in the region between 285 and 500 cm−1 exhibiting increased overlap and lowered maxima as compared to cellulose I and cellulose II.
A fibrous cellulosic product as described in any previous embodiment, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.25° 2Θ.
A fibrous cellulosic product of any preceding embodiment comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of from at least about 3.5° to about 7° 2Θ.
A fibrous cellulosic product as described in any previous embodiment, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak at 2Θ=20.6° for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° to about 7° 2Θ.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers:
A fibrous cellulosic product as described in any previous embodiment, comprising a useful article comprising conventional cellulosic fibers and nanoporous cellulose fibers.
A fibrous cellulosic product as described in any previous embodiment, comprising an assemblage of conventional cellulosic fibers and nanoporous cellulose fibers.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting an X-Ray diffraction peak at 2Θ=20.6° for the most prominent reflection and exhibiting broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the width of the tallest of said maxima in said spectrum between 285 and 400 cm−1 being at least about 30 cm−1, preferably at least about 35, 40 or 45 cm−1, and the width of the tallest of said maxima in said spectrum between 400 and 500 cm−1 being at least about 55 cm−1, preferably at least about 60, 65, 70 or 90 cm−1.
A fibrous cellulosic product as described in any previous embodiment, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0° 2Θ.
A fibrous cellulosic product as described in any previous embodiment, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.0°.
A fibrous cellulosic product as described in any previous embodiment, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said fibers exhibiting a broadened X-Ray diffraction peak for the most prominent reflection having a width at half-height, (W1/2h)A, of at least about 3.5°.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, the Raman Spectrum of said fibers exhibiting two broad peaks, one centered near 367 cm−1 and another lower peak centered near 441 cm−1, the peak centered near 367 cm−1 having a width at half height of at least about 30 cm−1, the peak centered near 441 cm−1 having a width at half height of at least about 55 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 355 and 360 cm−1, the height of the peak between 355 and 360 cm−1 being at least 34% of the height of the peak between 1094 and 1098 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 416 and 423 cm−1, the height of the peak between 416 and 423 cm−1 being at least 20% of the height of the peak between 1094 and 1098 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 487-493 cm−1, the height of the peak between 487 and 493 cm−1 being at least 25% of the height of the peak between 1094 and 1098 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 895 and 901 cm−1, the height of the peak between 895 and 901 cm−1 being at least 25% of the height of the peak between 1094 and 1098 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting a peak in its Raman spectrum between: 1260 and 1267 cm−1, the height of the peak between 1260 and 1267 cm−1 being at least 10% of the height of the peak between 1094 and 1098 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fiber exhibiting peaks in its Raman spectrum between:
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fiber, said nanoporous cellulose fiber exhibiting at least a first and a second peak in its Raman spectrum, said first peak falling into a band between: about 348 and 360 cm−1, about 416 and 424 cm−1, about 487 and 493 cm−1, about 895 and 901 cm−1, about 1094 and 1098 cm−1, or about 1260 and 1267 cm−1; said second peak falling into one of said bands other than the band into which said first peak falls; wherein the height of said first peak relative to the height of the peak between 1094 and 1098 cm−1 is:
A fibrous cellulosic product comprising conventional cellulosic fibers and nanoporous cellulose fiber, said nanoporous cellulose fiber exhibiting a multiplicity of peaks falling into defined bands in its Raman spectrum including at least one peak falling between 1094 cm−1 and 1098 cm−1, the height of each said peak relative to the height of said peak falling between 1094 cm−1 and 1098 cm−1 exceeding the minimum relative peak height for that band as set forth in the following table:
at least three peaks, other than said one peak between falling 1094 cm−1 and 1098 cm−1; both falling into one of said defined bands and exceeding the Minimum Relative Peak Height specified for that defined band.
A fibrous cellulosic product as described in any previous embodiment, wherein at least four of the peaks in the Raman spectrum of said cellulosic tissue product both fall into one of said defined bands and exceed the minimum relative peak height for the band into which it falls.
A fibrous cellulosic product as described in any previous embodiment, wherein at least five of the peaks in the Raman spectrum of said cellulosic tissue product both fall into one of said defined bands and exceed the minimum relative peak height for the band into which it falls.
A fibrous cellulosic product, comprising conventional cellulosic fibers and at least about 5% of nanoporous cellulose fibers, said nanoporous cellulose fibers exhibiting a doublet between 350 cm−1 and 385 cm−1 in their Raman spectrum.
A fibrous cellulosic product, comprising conventional cellulosic fibers and at least about 5% of nanoporous cellulose fibers, said nanoporous cellulose fibers exhibiting a doublet between 417 cm−1 and 445 cm−1 in their Raman spectrum.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fibers exhibiting at least two doublets, one centered between 350 cm−1 and 385 cm−1 and the other between 417 cm−1 and 445 cm−1.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fibers exhibiting doublets in their Raman spectrum between 350 cm−1 and 385 cm−1 as well as between 417 cm−1 and 445 cm−1.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers, said nanoporous cellulose fibers exhibiting at least two broad overlapping maxima in their Raman spectrum between 285 and 500 cm−1, the height of the two tallest of said maxima in said spectrum between 285 and 500 cm−1 being between 35 and 55% of the height of the peak near 1098 cm−1.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers prepared from wood pulp fibers, the Raman Spectrum of said nanoporous fibers exhibiting three broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1; another being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 and the third being a peak centered near 1098 cm−1, at least two of said peaks being at least 10% broader at half height than the corresponding peak in the pulp from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein at least two of said peaks are at least 15% broader at half height than the corresponding peak in the pulp from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein at least two of said peaks are at least 20% broader at half height than the corresponding peak in the pulp from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein at least one of said peaks is at least 100% broader at half height than the corresponding peak in the pulp from which it was prepared.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers prepared from cellulosic fibers, the Raman Spectrum of said nanoporous fibers exhibiting two broad peaks, one being a series of overlapping peaks between about 250 cm−1 to about 400 cm−1; and the other being a series of overlapping peaks between about 400 cm−1 to about 600 cm−1, each said peak being at least 10% broader at half height than the corresponding peak in the cellulosic fiber from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein each said peak is at least 15% broader at half height than the corresponding peak in the cellulosic fiber from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein each said peak is at least 20% broader at half height than the corresponding peak in the cellulosic fiber from which it was prepared.
The fibrous cellulosic product as described in any previous embodiment, wherein at least one of said peaks is at least 100% broader at half height than the corresponding peak in the pulp from which it was prepared.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers prepared from wood pulp fibers, the Raman Spectrum of said nanoporous fibers exhibiting three broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibiting a width at half height of at least about 30 cm−1; another being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 55 cm−1 and the third being a peak centered near 1098 cm−1 exhibiting a width at half height of at least about 46 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 35 cm−1; and the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 55 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 40 cm−1; the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 60 cm−1 and the peak centered near 1098 cm−1 exhibiting a width at half height of at least about 50 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 70 cm−1.
A fibrous cellulosic product, comprising conventional cellulosic fibers and nanoporous cellulose fibers prepared from cellulosic fibers, the Raman Spectrum of said nanoporous fibers exhibiting two broad peaks, one being a series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibiting a width at half height of at least about 30 cm−1; and the other being a series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibiting a width at half height of at least about 55 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 35 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 60 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 90 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 40 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 60 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 90 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 45 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 60 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 90 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 50 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 60 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 90 cm−1.
A fibrous cellulosic product as described in any previous embodiment, wherein the series of overlapping peaks between about 250 cm−1 and about 400 cm−1 exhibits a width at half height of at least about 45 cm−1; and the series of overlapping peaks between about 400 cm−1 and about 600 cm−1 exhibits a width at half height of at least about 75 cm−1.
A fibrous cellulosic product comprising conventional cellulosic fibers and cellulosic fiber having a Raman Spectrum exhibiting peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1 and exhibiting:
A fibrous cellulosic product comprising conventional cellulosic fibers and cellulosic fiber having a Raman Spectrum exhibiting peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1, with:
A fibrous cellulosic product comprising conventional cellulosic fibers and cellulosic fiber having a Raman Spectrum exhibiting peaks near 458, 1098, and 1600 cm−1, with:
A fibrous cellulosic product comprising conventional cellulosic fibers and cellulosic fiber having a Raman Spectrum exhibiting peaks near 380, 496, 897, 1098, 1590 and 1609 cm−1 and exhibiting:
An assemblage of cellulosic fibers comprising laterally expanded cellulose exhibiting a peak in its Raman spectrum near 2888 cm−1 and another peak near 3400 cm−1, the descent from the peak near 2888 cm−1 being smooth and without inflection points and only one local maximum being presented between 3200 cm−1 and 3600 cm−1.
While the invention has been described in detail with numerous examples and embodiments, modifications within the spirit and scope of the invention will be readily apparent to those of ordinary skill in the art. In view of the foregoing discussion, relevant knowledge in the art and references discussed above in connection with the Background and Detailed Description, the disclosures of which are all incorporated herein by reference, further description is deemed unnecessary.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5858021 | Sun et al. | Jan 1999 | A |
| 20050145348 | Lee | Jul 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| WO 2009124240 | Oct 2009 | WO |
| WO 2012037250 | Mar 2012 | WO |
| Entry |
|---|
| Wiley et al., Band Assignments in the Raman Spectra of Celluloses, The Institute of Paper Chemistry, Appleton, Wisconsin 54912 (U.S.A.), Carbohydrate Research, 160 (1987), pp. 113-129. |
| Appendix H of TAPPI Standard T 401 om-08, Fiber Analysis of Paper and Paperboard, (2008). |
| A Color Atlas for Fiber Identification, John H. Graff, published by the Institute of Paper Chemistry, Appleton, Wisconsin, 1940. |
| Number | Date | Country | |
|---|---|---|---|
| 20120273147 A1 | Nov 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61628698 | Nov 2011 | US | |
| 61518047 | Apr 2011 | US |
