KR100611280B1 - High Bulk, High Strength Fiber Material with Permanent Fiber Morphology - Google Patents

Abstract

The wood fiber form can be permanently modified by kink, twist, curl, crimp or other curve deformation to a significant degree. The wood fibers are first fiberized by a mechanical treatment process and then subjected to a super atmospheric temperature / pressure steam explosion process. The fiber form becomes time independent permanent fiber property while the fiber is otherwise processed or used.

Wood fiber, permanent fiber form, super-high temperature and pressure, steam explosion, fiberization

Description

High Bulk, High Strength Fiber Material with Permanent Fiber Morphology

The present invention relates generally to fibrous materials, and more particularly to fibrous materials made from wood. The present invention also relates to blends of materials consisting of fibreized and refined fibers, which exhibit high bulk and high strength. The present invention also relates to a method of permanently modifying the fiber form of fibrous wood fibers to produce unchanged high bulk, maximum surface area, low density wood fiber products. These properties are due to the permanent nature of kinks, twists, curls, crimps or other curved deformations formed inside the fibers. The blended fibers of the present invention can be used in tissues, distribution layers, filter papers, and other applications where high bulk, high surface area, low density due to fiber form can be usefully employed.

The use of steam or explosive decompression to decompose wood fibers is well known in the art. For example, Mason discloses the general techniques of vapor explosion treatment in his U.S. Pat.Nos. 1,586,159, 1,578,609, 1,655,618, 1,824,221, 1,872,996 and 1,922,313. These patents all relate generally to the decomposition of primary cellulose materials such as wood chips.

Subsequent patents disclose methods for incremental improvement and improvement in steam explosion treatment. For example, US Pat. No. 2,516,847 to Boehm relates to a means of sizing exploded fibers. Mitcherling, US Pat. No. 1,793,711, discloses using a vacuum source to remove volatile resin prior to performing the pressurizing and explosive decompression steps. Birdseye, US Pat. No. 2,711,369, improves explosive decompression treatment by adding a series of explosion steps. It is clear that this method breaks down the fibers more evenly. Lower pressures and temperatures may be used in this series of explosion stages.

U.S. Patent No. 4,163,687 to Mamers et al. Is a uniquely designed nozzle for assisting in the removal of fibers from cellulosic material during explosive defibration. The nozzle has a number of inner rods that form a serpentine path through which the material passes. O'Connor, US Pat. No. 3,707,436, discloses the use of ammonia in place of steam. Clearly, compounds such as ammonia are effective at swelling and plasticizing wood. Morgan, US Pat. No. 2,234,188, relates to the production of light colored cellulose fibers. This is achieved by first treating chips or other small pieces of wood with alkali sulfites of alkali metals such as sodium sulfite or potassium sulfite.

US Patent No. 4,488,932 to Robert J. Eber et al. Discloses the use of fiberized fibers to achieve improved bulk and ductility. However, curls and kinks loosen significantly during the wet-forming process. Thus, the patent describes the manufacture of tissue using a foam-forming process. The fibrillated fibers are dispersed in an aqueous foam that minimizes absorption of water, with the result that the treated fibers return to their original form.

U.S. Patent No. 5,102,501 to Robert J. Ever et al. Discloses improving bulk and ductility by depositing fibrous fibers on a forming wire and dehydrating them for a time short enough to maintain their bulk-enhancing properties. do.

However, although past attempts have been made to control the size, absorbency and bulking properties, there have been few teachings on methods useful for improving and maintaining the curl and kink properties of fiberized fibers. . In addition, in the past, it has never been proposed to blend fibrous / steam exploded fibers with highly refined fibers to form a sheet with high bulk but without loss of strength.

Thus, there is still a need for materials that exhibit high bulk while maintaining high strength.

Summary of the Invention

According to a first aspect of the present invention, there is provided a method of making fibers having a permanently modified fiber form. This method comprises the steps of: (a) mechanically modifying the papermaking fibers such that the fibers are not substantially destroyed to produce fibers having a temporary fiber form with a curl index of at least 0.15; (b) steaming this fiber, having a temporary fiber form, at a superatmospheric temperature and pressure for a time sufficient to make the fiber form permanent; (c) explosive release of superheat vapor pressure.

The fibers obtained in this way have a permanent curl index of at least 0.2.

Another aspect of the invention is a method of making fibers having a permanently modified fiber form. This method comprises: (a) hammermilling the papermaking fiber such that the fiber has a curved structure with a curl index of at least 0.2 such that the fiber is not substantially destroyed; (b) treating this fiber with a curved structure with steam at super-high temperature and pressure for about 0.5 to about 20 minutes to make the fiber form permanent; (c) explosive release of superheat vapor pressure.

The fibers obtained in this way have a permanent curl index of at least 0.2.

Another aspect of the present invention is an improved fiber material with increased bulk, comprising a blend of fibers having a permanent fiber form having a curl index of 0.2 or greater. This modified fiber is obtained by a method of first mechanically deforming the papermaking wood fibers and steaming the fibers thus obtained at superatmospheric temperature and pressure to obtain a permanent fiber form. This modified fiber is blended with the refined paper wood fiber. Within this blend are fibers having a permanent fiber form of about 0.01 to about 100 parts by weight per one part of refined papermaking fiber. This improved fiber material has a bulk of greater than 3.0 cm 3 / g.

This fiber material can form sheets with high bulk and high strength. This fibrous material can be used in tissues, towels or saturated paper basesheets. This material may also be used as a wicking dispensing material. The invention also relates to a fibrous material formed from a blend of fibrous fibers and refined fibers.

1 is a graph of tensile index versus bulk. Three lines are shown on the graph. One line is control (unprocessed) data. Another line is steam exploded data. The other line is the fibrosis / vapor exploded data.

FIG. 2 is a graph of curl index versus repulping time, entitled Curl Performance. Three sets of data are shown on the graph. One set is fiberized data. The other set is steam exploded data. The other set is fibrosis / vapor exploded data.

A method of making fibers having a permanently modified fiber form includes (a) mechanically modifying the papermaking fiber such that the fiber is not substantially destroyed to produce a fiber having a temporary fiber form with a curl index of at least 0.15, and (b) a temporary fiber form. Steaming the fibers at a super atmospheric temperature and pressure for a time sufficient to make the fiber form permanently, and (c) exploding the super atmospheric vapor pressure.

The fibers obtained in this way have a permanent curl index of at least 0.2.

It has been found that by treating the cellulose fibers using mechanical deformation and vapor explosion processes under appropriate processing conditions, modified cellulose fibers exhibiting the desired properties can be produced in an efficient and effective process.

Various cellulose fibers can be used in the process of the present invention. Examples of cellulose fibers include wood and wood products such as wood pulp fibers; Cotton, straw and grasses such as rice and African esparto, rattan and reeds such as sugarcane, bamboo, stems with bast fibers, such as jute, flax, sheep, marijuana, linen and Ramie grass, and non-wood papermaking fibers, such as those derived from leaf fibers, such as abaca and sisal, are included, but are not limited thereto. It is also possible to use mixtures of one or more cellulose fibers. Suitably, the cellulose fibers used are from wood sources. Suitable wood sources include softwood sources such as pine, spruce and fir, and hardwood sources such as oak, eucalyptus, poplar, beech and aspen poplar.

The term "fiber" or "fibrous" as used herein refers to a particulate material having a length to diameter ratio of greater than about 10. In contrast, “non-fibrous” or “non-fibrous” refers to a particulate material having a length to diameter ratio of about 10 or less, or more closely about 2 or less.

In this invention, it is preferable to use the cellulose fiber of the form refine | purified with pulp already. For example, the cellulose fibers will be substantially in the form of individual cellulose fibers, but these individual cellulose fibers may be in the form of aggregates such as pulp sheets. The process of the present invention is therefore in contrast to known vapor explosion processes which treat cellulosic fibers, typically in the form of virgin wood chips and the like. Thus, the process of the present invention is generally a post-pulping cellulose fiber modification process compared to known steam explosion processes used in high yield pulp production or waste-recycling processes.

Cellulose fibers used in the vapor explosion process are preferably low yield cellulose fibers. As used herein, the term "low yield" cellulose fiber is advantageously produced by a pulping process in a yield of about 85% or less, suitably about 80% or less, and more suitably about 55% or less. Refers to cellulose fibers. In contrast, “high yield” cellulose fibers refer to cellulose fibers produced by the pulping process advantageously in yields of about 85% or more. This pulping process generally produces cellulose fibers containing high levels of lignin.

As used herein, the term "permanent fiber morphology" is defined as the fiber property remaining after the fiber has been repulped for up to 300 minutes, preferably 150 to 300 minutes. The term "transient or temporary fiber morphology" is defined as a fiber property that does not remain after the fiber has been repulped for less than 150 minutes.

In the process of the present invention, it has been found that the use of mechanical explosion followed by steam explosion can produce fibers that exhibit permanent curl form. This permanent deformation of the fiber form has a positive effect on the cost (bulk) and absorbency of the sheets made of such fibers. This fiber curl form becomes a permanent characteristic of the time independent fibers while the fibers are otherwise processed or used.

By mechanically deforming the fibers, temporary curl forms can be achieved. Such mechanical deformation does not destroy much of the fiber. Various refining and hammer milling methods known in the art can be used to provide temporary curl forms. A preferred means of mechanically modifying the fibers is a hammer mill.

Generally the fibers enter the hammer mill with an equilibrium moisture content of 15% by weight. The fibers exit the hammer mill with an equilibrium moisture content of 1 to 5% by weight. Hammer mills are typically operated in a temperature range of 50 to 100 ℃.

The temporary curl form achieved by the hammer mill is mainly generated due to the shear force applied to the fiber as it penetrates between the anvil and the rotating hammer. The average residence time of the fibers in the hammer mill is generally less than 1 second. The fibers after mechanical deformation generally exhibit a curl index greater than 0.15 and typically greater than 0.2. The temporary curl form of the fiber is enhanced and made permanent by the subsequent vapor explosion treatment.

Following mechanical deformation, the fibers are subjected to a steam explosion treatment. In addition, even when steam explosion alone is used, the cellulose fibers can be sufficiently effectively modified so that the modified cellulose fibers exhibit the desired properties, in particular, the desired liquid absorbency. Generally, cellulosic fibers are treated in a saturated vapor environment that is substantially air free. The presence of air in the pressurized processing environment can oxidize cellulose fibers. For example, the cellulose fibers may advantageously contain less than about 5 weight percent, suitably less than about 3 weight percent, more suitably less than about 1 weight percent air based on the total weight of the gaseous environment present in the pressurized processing environment. It is desirable to treat in a saturated steam environment, including.

Individual cellulosic fibers are steamed at high temperature and pressure. In general, any combination of high pressure, high temperature and time effective to achieve the desired level of modification without adversely affecting the cellulose fibers, such that the cellulose fibers exhibit the desired fiber curl properties described herein, can be used in the present invention. Suitable for

In general, if the temperature used is too low, modification of the cellulose fibers will not occur at substantial and / or effective levels. Also, in general, if the temperature used is too high, the cellulose fibers will be substantially degraded, which will negatively affect the properties exhibited by the treated cellulose fibers. Thus, in general, the cellulose fibers are advantageously in the range of about 130 to about 250 ° C., suitably about 150 to about 225 ° C., more suitably about 160 to about 225 ° C., and most suitably about 160 to about 200 ° C. It will be processed at the temperature entering it.

Generally, the cellulose fibers will be subjected to elevated superatmospheric pressure for a time falling within the range of about 0.1 to about 30 minutes, advantageously about 0.5 to about 20 minutes, suitably about 1 to about 10 minutes. In general, the higher the temperature used, the shorter the time generally required to achieve the desired level of modification of the cellulose fibers. Thus, different combinations of high temperature and time can be used to modify different cellulosic fiber samples to essentially equivalent levels.

In general, if the pressure used is too low, modification of the cellulose fibers will not occur at substantial and / or effective levels. Also, if the pressure used is generally too high, the cellulose fibers will be substantially degraded, which will negatively affect the properties exhibited by the crosslinked cellulose fibers. Thus, in general, the cellulose fibers are advantageously about 2.81 to about 28.47 kg / cm 2 (about 40 to about 405 lb / in ² ), suitably about 2.81 to about 16.17 kg / cm 2 (about 40 to about 230 lb / in ² ), more suitably at a superatmospheric pressure (ie, a pressure above standard atmospheric pressure) that falls within the range of about 6.33 to about 16.17 kg / cm 2 (about 90 to about 230 lb / in ² ).

As used herein, "consistency" refers to the concentration of cellulose fibers present in an aqueous mixture. For example, consistency is expressed as weight percent, which is 100 times the weight of cellulose fibers present in the aqueous mixture divided by the total weight of cellulose fibers and water present in such mixture.

In general, cellulose fibers can be used in the dry or wet state in the process of the present invention. However, it may be desirable to prepare an aqueous mixture comprising cellulose fibers, wherein the aqueous mixture is shaken, stirred or blended to effectively disperse the cellulose fibers in water. In one embodiment of the present invention, the cellulose fibers are advantageously from about 10 to about 100 weight percent, suitably from about 20 to about 80 weight percent, more suitably from about 25 to, based on the total weight percent of the aqueous pulp mixture When present in the form of an aqueous pulp mixture having a consistency of about 75% by weight cellulose fibers, the cellulose fibers are preferably steamed.

Cellulose fibers are typically mixed with an aqueous solution comprising at least about 30% by weight, suitably about 50% by weight, more suitably about 75% by weight, and most suitably 100% by weight of water. When other liquids are used with water, suitable as other liquids include methanol, ethanol, isopropanol and acetone. However, when these other non-aqueous liquids are used or present, they inherently interfere with the formation of a homogeneous mixture such that the cellulose fibers cannot be effectively dispersed in the aqueous solution or effectively or uniformly mixed with water. Such mixtures should generally be prepared under conditions sufficient to effectively mix the cellulose fibers and water together. Generally, such conditions include temperatures of about 10 to about 100 degrees Celsius.

Generally, cellulose fibers are produced by pulping or other manufacturing processes in which the cellulose fibers are present in aqueous solution. Therefore, for use in the vapor explosion treatment of the present invention, it may be possible to obtain and use directly from the above manufacturing process without separately recovering cellulose fibers.

After steaming the cellulose fibers, the pressure is released and the cellulose fibers are exploded into a release vessel. The pressure may be vented by exhaust or by various methods known in the art.

The apparatus or method used to vapor explode the cellulose fibers is generally not critical. Apparatuses and methods suitable for vapor explosions are described, for example, in Canadian Patent No. 1,070,537, filed Jan. 29, 1980, incorporated herein by reference in its entirety; Canadian Patent No. 1,070,646, January 29, 1980; Canadian Patent No. 1,119,033, filed March 2, 1982; Canadian Patent No. 1,138,708, issued January 4, 1983; And US Pat. No. 5,262,003, issued November 16, 1993.

Vapor explosion processes generally modify cellulose fibers. Although not intended to be limiting, it is believed that the cellulose fibers are curled by a mechanical strain / vapor explosion process. In addition to being modified, steam exploded cellulose fibers have been found to exhibit improved properties for use in liquid absorption or liquid handling applications.

Cellulose fibers suitable for use in the present invention generally do not have substantial levels of curl before being subjected to mechanical strain / vapor explosion processes (generally less than 0.2 curl index). After this mechanical strain / steam explosion process, the treated cellulose fibers will generally exhibit a stable level of curl at a desired level (generally a curl index greater than 0.2). For example, in the process of the present invention, it is generally not necessary to add any additional additives to the cellulose fibers during the steam explosion process or during any post-treatment step after steam exploding the fibers to achieve the desired curl.

In one embodiment of the present invention, cellulose fibers are considered to be effectively treated by a steam explosion process when they exhibit an effective Wet Curl value of greater than 0.2.

The curl of the fiber can be quantified by the curl value, which measures the fractional shortening of the fiber due to kinks, twists, and / or bends in the fiber. For the purposes of the present invention, the curl value of a fiber is a measured value by a two-dimensional plane, which is determined by observing the fiber on a two-dimensional plane. To determine the curl value of the fiber, both the longest dimension l of the two-dimensional rectangle containing the fiber, L, which is the protruding length of the fiber, is measured. Measure L and l using image analysis method. Suitable image analysis methods are described in US Pat. No. 4,898,642, which is incorporated herein by reference in its entirety. The curl value of the fiber can then be calculated from the following formula: curl value = (L / l) -1

Depending on the nature of the curl of the cellulose fiber, the curl may be stable when the cellulose fiber is dry but unstable when the cellulose fiber is wet. Cellulose fibers produced according to the process of the present invention have been found to exhibit substantially stable fiber curls when wet. The properties of cellulose fibers can be quantified by the wet curl value, which is the length weighted average curl average of fibers taken from a number of fibers (for example about 4000) from a fiber sample, as measured according to the test methods described herein. For example, the wet curl value is the sum of the individual wet curl values of each fiber multiplied by the actual length L of the fiber, divided by the sum of the actual lengths of the fibers. Note that the wet curl value as determined herein is calculated using only the necessary values for the fibers whose length is greater than about 0.4 mm.

As used herein, the cellulose fibers are wetted greater than about 0.2, advantageously from about 0.2 to about 0.4, more advantageously from about 0.2 to about 0.35, suitably from about 0.22 to about 0.33, suitably from about 0.25 to about 0.33. When showing curl values, cellulose fibers are considered to have been effectively treated by steam explosion treatment. In contrast, untreated cellulose fibers generally exhibit a wet curl value of less than about 0.2.

After cellulose fibers are effectively mechanically deformed / steam exploded, the treated cellulose fibers are suitable for use in a variety of applications. However, depending on the use of the treated cellulose fiber, the treated cellulose fiber may be washed with water. Other recovery and aftertreatment steps are also known when planning any further treatment processes because of the particular use of the treated cellulosic fibers.

New fiber materials can be prepared by blending highly refined fibers with mechanically deformed / steam exploded high bulk fibers. Highly refined fibers are raw fibers refined to about 300 to 500 Canadian standard degrees of freedom (C.S.F). As shown in Tables 2 and 3 and FIG. 1, at certain blend ratios, the blended fibers form a sheet that is much bulkier than the untreated fiber sheet and does not lose strength.

Cellulose fibers treated according to the process of the present invention include disposable absorbent products such as diapers, incontinence products and bed pads; Menstrual devices such as sanitary napkins and tampons; Other absorbent products such as wipes, bibs, wound dressings and surgical capes or drapes; And tissue-based products such as cosmetic or toilet tissues, household towels, wipes and related products. Thus, in another aspect, the present invention relates to a disposable absorbent article comprising cellulose fibers treated according to the process of the present invention.

In one embodiment of the present invention, the fibers treated according to the process of the present invention are formed into a handsheet that can represent a tissue-based product. Such handsheets may be formed by a wet-laid or air-laid process. Wet-laid handsheets may be prepared according to the methods disclosed in the “Test Methods” section herein.

It has been found that wet-laid handsheets made from cellulose fibers treated according to the process of the invention may exhibit lower densities than wet-laid handsheets made from cellulose fibers not treated according to the process of the invention.

In addition, wet-laid handsheets made from cellulose fibers treated according to the process of the present invention exhibit higher bulk and higher absorption capacity than wet-laid handsheets made from cellulose fibers not treated according to the process of the present invention. It turns out that you can.

In one embodiment of the invention, the cellulose fibers treated according to the process of the invention are formed into a fibrous matrix for use in the absorbent structure. The fibrous matrix can take the form of, for example, a batt of pulverized wood pulp fluff, a tissue layer, a hydroentangled pulp sheet, or a mechanically softened pulp sheet. Examples of absorbent structures are generally described in co-pending US patent application 60 / 008,994, which is incorporated herein by reference in its entirety.

The fibrous matrix useful in the present invention may be prepared by an air-laying process or a wet-laid process, or by a process of making essentially any other fibrous matrix known to those skilled in the art.

In one embodiment of the invention, a liquid-permeable topsheet, a backsheet attached to the liquid-permeable topsheet, a cellulose fiber treated according to the process of the invention, located between the liquid-permeable topsheet and the backsheet. A disposable absorbent article is provided that includes an absorbent structure that includes.

Examples of disposable absorbent articles are generally described in documents US-A-4,710,187; US-A-4,762,521; US-A-4,770,656; And US-A-4,798,603.

Those skilled in the art will know suitable materials for use as the topsheet and backsheet. Suitable materials for use as the topsheet are liquid-permeable materials such as spunbond polypropylene or polyethylene having a basis weight of about 15 to about 25 g / m 2. Examples of suitable materials for use as the backsheet are liquid-impermeable materials such as polyolefin films, as well as vapor-permeable materials such as microporous polyolefin films.

Absorbent articles and structures according to all aspects of the present invention are generally applied to body fluids that are released multiple times during use. Thus, it is desirable for the absorbent article and the structure to be able to absorb bodily fluids that are released multiple times by the amount that the absorbent article and the structure are exposed during use. Body fluids are usually drained separately from each other periodically.

Test Methods

Wet curl

The wet curl value of the fiber was determined from Op Test Equipment Inc., Hyokesbury, Ontario, Canada, with Fiber Quality Analyzer, Op Test Product Code DA93 (Fiber Quality Analyzer, Op Test Product Code DA93). The quality of the fibers, marketed under the designation), was determined using a machine that quickly, accurately and automatically determined.

Dried cellulose fiber samples were obtained. This cellulose fiber sample was poured into a 600 ml plastic sample beaker used in a fiber quality analyzer. Fiber samples in the beakers were diluted with tap water until the fiber concentration in the beakers was between about 10 and about 25 fibers per second as analyzed by a fiber quality analyzer.

The empty plastic sample beaker was filled with tap water and placed in a fiber quality analyzer test chamber. I then pressed the System Check button on the Fiber Quality Analyzer. When the plastic sample beaker filled with tap water was properly positioned in the test chamber, the OK button of the fiber quality analyzer was pressed. The fiber quality analyzer was then self-tested. If no warning is displayed on the screen after the self-test, the machine is ready to test the fiber sample.

A plastic sample beaker filled with tap water was removed from the test chamber and a fiber sample beaker was placed therein. I pressed the Measure button on the Fiber Quality Analyzer. I then pressed the Fiber Channel's New Measurement button. The identity of the fiber sample was then typed into a fiber quality analyzer. Then I pressed the OK button on the Fiber Quality Analyzer. Then I pressed the <Options> button on the Fiber Quality Analyzer. The number of fibers was set to 4,000. The scale variable of the graph to be output can be set automatically or to a desired value. Then I pressed the Previous button on the Fiber Quality Analyzer. Then I pressed the <Start> button on the Fiber Quality Analyzer. When the fiber sample beaker was properly positioned in the test chamber, the OK button of the fiber quality analyzer was pressed. The fiber quality analyzer then initiated the test and indicated the fibers passing through the flow cell. The fiber quality analyzer also indicates the frequency of fibers passing through the flow cell, which should be about 10 to about 25 fibers per second. If the fiber frequency is outside this range, the fiber quality analyzer's <Stop> button must be pressed and the fiber sample diluted or additional fibers added to the fiber sample to ensure that the fiber frequency is within the desired range. Once the fiber frequency was sufficient, the fiber quality analyzer tested the fiber sample until it reached 4000 fibers, the point where the fiber quality analyzer automatically stopped. Then I pressed the Results button on the Fiber Quality Analyzer. The fiber quality analyzer calculates the wet curl value of the fiber sample and prints it by pressing the <Done> button on the fiber quality analyzer.

Method of Making Refined Fiber

Refined fibers were prepared using a Laboratory Valley beater according to the Technical Association of Pulp and Paper Industry (TAPPI) test method (T200 om-89). The Canadian standard degree of freedom of the fiber is a measure of the degree of refinement of the fiber and was measured by the TAPPI test method (T227 om-92).

Manufacturing method of wet-laid hand sheet

(A) Hand Sheet Forming

A 19.05 cm by 19.05 cm (7.5 inch by 7.5 inch) handsheet with a basis weight of about 60 g / m 2 was prepared using an 8 × 8 inch Valley Handsheet mold. The sheet mold forming wire was a 90 × 90 mesh, stainless-steel wire cloth with a wire diameter of 0.01397 cm (0.0055 inches). The backing wire was 14 × 14 mesh, plain weave bronze with a wire diameter of 0.021 inches. The well mixed stock was taken in an amount sufficient to make a handsheet of about 60 g / m 2 and the stock container of the sheet mold was clamped in place on the wire. A few inches of water rose above the wire. Weighed stock was added and the mold filled with water up to six inches on the wire. A perforated mixing plate was inserted into the mixture in the mold and slowly moved up and down seven times. The water leg drain valve was opened immediately. When the water and stock mixture drained and disappeared from the wire, the drain valve was closed. The cover of the sheet mold was raised. Clean, dry blotter was carefully placed on the formed fibers. A dry couch roll was placed on the leading edge of the blotter paper. The fibers stuck to the blotter paper were couched away from the wire by passing the couching roll once in front of the wire back without applying pressure.

(B) handsheet crimp

The sheet of paper and the fibrous mat adhered thereto were placed in a hydraulic press on the two sheets of paper that were used and then re-dried, with the handsheet facing up. Two new blotter papers were placed on the handsheet. The press was closed and clamped. Pressure was applied to produce 5.27 kg / cm 2 (75 psi) on the pressed surface affected by the press. This pressure was maintained for exactly 1 minute. The pressure on the press was then released. The press was opened and the handsheets collected.

(C) Hand Sheet Drying

The handsheet was placed on the glossy side of the sheet dryer (Valley Steam hot plate). The canvas cover was carefully lowered onto the sheet. 5.9 kg (13 lb) of dead weight were held in a lead-filled brass tube. The sheet was dried for 2 minutes. When the cover was removed, the surface temperature was on average 100.5 ± 1 ° C. The sheet was collected from the dryer and cut out to 19.05 x 19.05 cm (7.5 x 7.5 inches). The weight of the sheet was measured immediately.

(D) Hand Sheet Test

Handsheets were tested at 50% humidity and 22.8 ° C. (73 ° F.). The bulk, burst index, tear index and tensile index of the handsheets were tested according to the TAPPI test method (T220 om-88).

Bulk and dry density of absorbent structures

From handsheets prepared according to the process described herein, strips of handsheet material samples about 2 inches wide and about 15 inches long were produced, for example, at Eastman Machine Corp., Buffalo, NY, USA. Made using a commercially available fabric saw. Sample strips were cut at least about 1 inch from the edge of the handsheet to avoid edge effects. Sample strips were marked with water-soluble ink at about 10 mm intervals.

In order to measure the bulk of the sample strip, a precision bulk meter up to about 0.01 mm or more, such as a bulk meter commercially available from Mitutoyo Corporation, was used. To measure the bulk, a platen of about 2.54 cm (1 inch) diameter, used parallel to the bottom of the bulk meter, was used. The bulk of the sample strip was measured at about 50 mm intervals along the length of the sample sheet and averaged. The average bulk, weight and dimensions of this sample strip were then used to calculate the dry density of the sample strip. After evaluating the Liquid Flux value of the sample strip, the wet density of the sample strip can also be determined in a similar manner.

Experiment result

The basic raw material was Kimberly-Clark's northern softwood (ie LL-19) kraft. The fiber was divided into two parts. A portion of the raw fiber was fiberized by a lab Pullmann fiberizer and the fiberized fiber was steam exploded. These composite treatments made it possible to produce fibers that form very large but very soft sheets. Another portion of the raw fiber was refined to low degrees of freedom (about 300 mL C.S.F.) using a lab valley beater. New fiber materials can be made by blending highly refined fibers with high bulk soft fibers at various bonding ratios. At certain blend ratios, the blended fibers form fiber materials that are much bulkier and do not lose strength as compared to untreated fibers.

Table 1 shows the properties of the fiber (LL-19) refined for 0 to 60 minutes in a valley beater.

Table 2 shows the physical properties of various blends of 60 minute refined fiber (LL-19) and vapor exploded fiber (LL-19).

Table 3 shows the physical properties of the various blends of 60 minute refined fibers (LL-19) and fibrillated / steam exploded fibers (LL-19).

Valley beater experiment LL-19 minute 0 3 5 15 30 45 60 Canadian standard degrees of freedom (Ml) 705 695 685 635 560 430 315 Burst index (kPam ² / g) 1.06 1.62 2.24 4.59 6.22 7.89 8.04 bulk (Cm 3 / g) 2.39 2.29 2.15 1.99 1.84 1.81 1.68 SCOTT BOND (ft.lb.) 0.022 0.030 0.038 0.150 0.225 0.388 Greater than 0.500 Tensile index (Nm / g) 20.97 29.04 36.45 65.14 80.46 97.82 102.09 Elongation (%) 1.76 2.24 2.46 3.61 4.07 4.65 4.64 Tensile energy absorption (J / ㎡) 13.47 24.66 33.71 84.60 114.21 150.50 156.49 Opacity, ISO (%) 76.8 76.6 74.9 73.5 70.4 69.9 67.7 Scattering coefficient (㎡ / ㎏) 37.55 37.32 34.14 31.63 27.03 26.34 23.67 Extinction coefficient (㎡ / ㎏) 0.24 0.24 0.24 0.26 0.28 0.28 0.29 Porosity, Frazier (cfm / ft ² ) 80.5 54.4 43.5 16.0 6.5 2.0 1.5

Blend identifier A B C D E F G LL-19 refined for 60 minutes with Valley Bitter 0 5% 10% 15% 20% 25% 30% Exploded LL-19 (2 min / 200 C / 75% Cons) 100% 95% 90% 85% 80% 75% 70% PFI Rotation 0 0 0 0 0 0 0 SI converted average test data Burst Index (kPa㎡ / g) 0.60 0.82 1.10 1.33 1.63 1.86 2.22 Cost (cm 3 / g) 2.73 2.69 2.58 2.57 2.50 2.41 2.40 Tear index (mN㎡ / g) 8.88 9.40 12.96 13.96 16.82 18.27 18.83 Tensile Index (Nm / g) 12.87 15.03 18.11 21.31 24.67 27.36 31.42 Tensile Energy Absorption (J / ㎡) 5.92 8.18 12.32 16.78 21.40 24.83 31.77 Average physical test data Canadian standard degrees of freedom (ml) 705 685 680 665 655 625 600 Burst (psi) 5.2 7.1 9.6 11.6 14.2 16.2 19.3 Bulk (in) 0.0064 0.0064 0.0061 0.0061 0.0059 0.0057 0.0057 Tear (g) 54.3 57.5 79.3 85.4 102.9 111.8 115.2 Tensile (lbs) 4.38 5.11 6.16 7.24 8.39 9.30 10.68 Elongation (%) 1.385 1.556 1.873 2.097 2.317 2.439 2.659 Tensile Energy Absorption (ftlb / ft ² ) 0.405 0.561 0.844 1.149 1.466 1.701 2.176 Scott Inner Coupling (ftlb) 0.026 0.024 0.027 0.031 0.031 0.034 0.038 Porosity (prayer) (cfm / ft ² ) 128.4 94.1 89.3 66.3 62.0 55.1 35.6 Average optical test data (ISO) Brightness (%) 84.44 84.56 84.64 84.65 84.77 84.66 84.75 (ISO) Opacity (%) 78.57 78.23 78.26 77.65 78.02 77.78 77.48 Scattering Coefficient (㎡ / ㎏) 40.22 39.65 39.81 38.67 39.40 38.82 38.29 Extinction coefficient (㎡ / ㎏) 0.28 0.28 0.27 0.27 0.27 0.27 0.27 L ^* (%) 95.52 95.53 95.57 95.54 95.57 95.51 95.50 a ^* (%) -0.19 -0.18 -0.20 -0.20 -0.20 -0.20 -0.20 b ^* (%) 3.38 3.29 3.26 3.20 3.15 3.12 3.03

Blend identifier H I J K L M N LL-19 refined for 60 minutes with Valley Bitter 0 5% 10% 15% 20% 25% 30% Fibrous and exploded LL-19 (2 min / 200 C / 75% Cons) 100% 95% 90% 85% 80% 75% 70% PFI Rotation 0 0 0 0 0 0 0 SI converted average test data Burst Index (kPa㎡ / g) 0.15 0.24 0.40 0.60 0.79 1.00 1.29 Cost (cm 3 / g) 3.87 3.74 3.43 3.27 3.23 3.01 2.94 Tear index (mN㎡ / g) 4.64 6.08 7.20 9.48 11.62 12.37 13.44 Tensile Index (Nm / g) 3.74 5.72 7.37 9.50 13.22 16.07 18.19 Tensile Energy Absorption (J / ㎡) 0.85 1.57 2.54 3.99 8.21 11.31 11.96 Average physical test data Canadian standard degrees of freedom (ml) 735 730 720 710 700 660 670 Burst (psi) 1.3 2.1 3.5 5.2 6.9 8.7 11.2 Bulk (in) 0.0091 0.0088 0.0081 0.0077 0.0076 0.0071 0.0069 Tear (g) 28.4 37.2 44.1 58.0 71.1 75.7 82.2 Tensile (lbs) 1.27 1.94 2.51 3.23 4.49 5.46 6.18 Elongation (%) 0.821 0.925 1.071 1.200 1.628 1.854 1.779 Tensile Energy Absorption (ftlb / ft ² ) 0.058 0.108 0.174 0.274 0.563 0.774 0.819 Scott Inner Coupling (ftlb) 0.014 0.020 0.022 0.026 0.030 0.034 0.038 Porosity (prayer) (cfm / ft ² ) 422.7 304.5 283.4 203.0 188.6 165.4 141.3 Average optical test data (ISO) Brightness (%) 83.63 83.93 83.83 84.16 84.21 84.38 84.33 (ISO) Opacity (%) 77.28 78.66 78.60 78.32 78.26 76.13 77.27 Scattering Coefficient (㎡ / ㎏) 35.54 37.30 37.74 39.59 39.37 35.35 37.11 Extinction coefficient (㎡ / ㎏) 0.28 0.29 0.29 0.29 0.29 0.26 0.27 L ^* (%) 95.27 95.31 95.30 95.45 95.41 95.45 95.43 a ^* (%) -0.16 -0.18 -0.18 -0.18 -0.16 -0.18 -0.21 b ^* (%) 3.56 3.41 3.36 3.37 3.24 3.16 3.16

The above specification, examples and data fully describe the preparation and use of the composition of the present invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention is based on the following appended claims.

Claims (20)

(a) mechanically modifying the papermaking fibers to produce fibers having a temporary fiber form with a curl index of at least 0.15, and (b) these fibers having a temporary fiber form, from 0.1 to 30 to make the fiber form permanent. Steaming at super-air temperature and pressure for a period of minutes, and (c) explosive expiration of super-air vapor, wherein the fibers obtained in this way have a permanently modified fiber form having a permanent curl index of at least 0.2 Method of making fibers. The method of claim 1 wherein the fibers comprise refined papermaking wood fibers or recycled papermaking wood fibers. The method of claim 1 wherein the mechanical deformation process comprises a hammermill process to deform the fiber to create a fiber having a curved structure. The method of claim 1, wherein the superhigh temperature comprises a temperature of 130 to 250 ° C. 3. The method of claim 1 wherein the superatmospheric pressure comprises a pressure between 2.81 and 28.47 kg / cm 2 (40 to 405 psi). delete The method of claim 1 wherein the fibers obtained by this method have a permanent curl index of 0.2 to 0.35. The method of claim 1 wherein the fibers obtained by this method have a permanent curl index of 0.22 to 0.33. The method of claim 1, wherein the fiber having a permanent fiber form is blended with the refined paper wood fiber at a ratio of 1 part of papermaking wood fiber per 0.01 to 100 parts of the fiber having a permanent fiber form. (a) hammermilling the papermaking fibers to produce a fiber having a curved structure with a curl index of 0.2 or greater, and (b) steaming the fiber having a curved structure at super-high temperature and pressure for 0.5 to 20 minutes. Thereby permanently making the fiber form, and (c) exploding the super-air vapor, wherein the fiber obtained in this way has a permanent curl index of at least 0.2. The method of claim 10 wherein the fibers comprise refined papermaking wood fibers. The method of claim 10 wherein the super-air temperature comprises a temperature of 150 to 220 ° C. in a sealed continuous process vessel. The method of claim 10 wherein the super atmospheric pressure comprises a pressure of 2.81 to 16.17 kg / cm 2 (40 to 230 psi) in a sealed continuous process vessel. The process of claim 10 wherein the process of steaming fibers having a curved structure at superatmospheric temperature and pressure is carried out in a sealed continuous process vessel for 1 to 10 minutes. The method of claim 10, wherein the fibers having a permanent fiber form are blended with the refined paper wood fiber at a ratio of 1 part of papermaking wood fiber per 100 parts of fiber having a permanent fiber form. First, a fiber having a permanent fiber form with a curl index of 0.2 or more, obtained by mechanically deforming the paper wood fiber and steaming the fiber at a super-high temperature and pressure to obtain a permanent fiber form; An improved bulk material improved fiber material having a bulk greater than 3.0 cm 3 / g, wherein the wood fibers comprise blends blended at a ratio of 0.01 to 100 parts by weight of fiber having a permanent fiber form per 1 part by weight of refined papermaking fiber. A tissue material formed from the fibrous material of claim 16. A towel material formed from a fiber material comprising the fiber material of claim 16. A wicking material formed from the fiber material of claim 16. An absorbent article containing the wicking material of claim 19.

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