ENZYMATIC PAPER AND PROCESS OF MAKING THEREOF

Abstract

The present invention includes a process for making paper. The process may include the steps of providing pulp fibers in a chest and adding an enzymatic material to the pulp fibers at a storing stage for decreasing cellulose crystals. Furthermore, the process may include adding a strength agent to the pulp fibers at the storing stage.

Description

FIELD OF THE INVENTION

[0001] This invention generally relates to the field of paper making, and more specifically, to an enzymatic prepared paper.

BACKGROUND

[0002] Generally, paper products such as towels and tissues are designed to combine several important attributes. For example, the products should have good bulk, softness, absorbency, and strength.

[0003] In the past, many attempts have been made to enhance and increase certain physical properties of paper products. Unfortunately, steps taken to increase one property of a paper product may adversely affect other product characteristics. As an example, softness and bulk can be increased by decreasing or reducing interfiber bonding within the paper web. However, inhibiting or reducing fiber bonding by chemical and/or mechanical means adversely affects the strength of the product. A challenge encountered in designing paper products is increasing softness, bulk, and absorbency without decreasing strength.

[0004] Accordingly, there is a need for a paper product having improved softness, bulk, and absorbency after undergoing fiber modification while maintaining at least the same strength properties.

DEFINITIONS

[0005] As used herein, the term “comprises” refers to a part or parts of a whole, but does not exclude other parts. That is, the term “comprises” is open language that requires the presence of the recited element or structure or its equivalent, but does not exclude the presence of other elements or structures. The term “comprises” has the same meaning and is interchangeable with the terms “includes” and “has ”.

[0006] As used herein, the term “cellulose” refers to a natural carbohydrate high polymer (polysaccharide) having the chemical formula (C5H10O5)n and consisting of anhydroglucose units joined by an oxygen linkage to form long molecular chains that are essentially linear. Natural sources of cellulose include deciduous and coniferous trees, cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse.

[0007] As used herein, the term “pulp” refers to cellulose processed by such treatments as, for example, thermal, chemical and/or mechanical treatments.

[0008] As used herein, the term “fiber” refers to a fundamental form of solid, usually crystalline, characterized by relatively high tenacity and an extremely high ratio of length to diameter, as an example, several hundred to one.

[0009] As used herein, the term “bleached-chemical-thermo-mechanical pulp” refers to processing cellulosic material with steam, pressure and sodium sulfite or hydrogen peroxide to soften wood lignin between and within cell walls. Furthermore, alkaline peroxide bleaching is added to further soften and brighten the fibers. The term bleached-chemical-thermo-mechanical pulp may be hereinafter abbreviated as “BCTMP”.

[0010] As used herein, the term “sulfite pulp” refers to pulp processed chemically with a mixture of sulfurous acid and bisulfite ion.

[0011] As used herein, the term “basis weight” (hereinafter may be referred to as “BW”) is the mass per unit area of a sample and may be reported as gram per meter squared and abbreviated “gsm”. The basis weight was measured using a test procedure hereinafter described.

[0012] As used herein, the term “specific volume” refers to values determined as described herein and may be expressed in units of cubic centimeters per gram.

[0013] As used herein, the term “weight percent” refers to a percentage calculated by dividing the weight of an element of a mixture by the total weight of the mixture multiplied by 100.

[0014] The term “machine direction” as used herein refers to the direction of travel of the forming surface onto which fibers are deposited during formation of a material.

[0015] The term “cross-machine direction” as used herein refers to the direction that is perpendicular and in the same plane as the machine direction.

[0016] As used herein, the term “tear index” refers to values determined as described herein and may be expressed as Newton times meter cubed divided by gram, which may be abbreviated “mNm2/g”.

[0017] As used herein, the term “tensile index” refers to values determined as described herein and may be expressed as Newton times meter divided by gram, which may be abbreviated “Nm/g”.

[0018] As used herein, the term “machine direction tensile” (hereinafter may be referred to as “MDT”) refers to values determined as described herein and may be reported as gram-force, which may be abbreviated “g”.

[0019] As used herein, the term “Frazier Porosity” refers to values determined as described herein and may be expressed as cubic feet per minute divided by feet squared, which may be abbreviated “cfm/ft2”.

[0020] As used herein, the term “absorbency” refers to values determined as described herein and may be expressed as seconds, which may be abbreviated “sec”.

[0021] As used herein, the term “geometric mean breaking length” (hereinafter may be referred to as “GMBL”) is the measurement of the strength of a material, generally a fabric or nonwoven web, and may be reported in length measurements, such as meters. The greater the geometric mean breaking length generally relates to a stronger material. The geometric mean breaking length is calculated by the formula:

GMBL=(MDT*CDT)0.5/BW

[0022] As used herein, the term “wicking” refers to values determined as described herein and may be expressed as gram of liquid divided by gram of material divided by seconds, which may be abbreviated “g/g/sec”.

[0023] As used herein, the term “water capacity” refers to values determined as described herein and may be expressed as grams of absorbed water divided by gram of material absorbing the liquid, which may be abbreviated “g/g”.

[0024] As used herein, the terms “permeable” and “permeability” refer to the ability of a gas to pass through a particular porous material under a prescribed pressure differential. Permeability may be expressed in units of volume per unit time per unit area, for example, cubic feet per minute per 38 square centimeter of material, which may be abbreviated “cfm”. Permeability was determined utilizing a Textest permeability tester sold under the trade designation FX-3300 from the Benninger Corp. and measured in accordance with ASTM D-737-96 and TAPPI T 251 cm-85.

[0025] As used herein, the term “percent solids” refers to the amount of solids in a pulp after being formed on a forming fabric but prior to drying. As an example, a pulp having 75 percent solids would consist of 75 weight percent of fibers and other solids, and 25 weight percent of water.

SUMMARY OF THE INVENTION

[0026] The problems and needs described above are addressed by the present invention, which provides a process for making paper. The process may include the step of adding an enzymatic material at a storing stage of a papermaking process to modify the pulp. Furthermore, the process may include adding a strength agent to the pulp at the storing stage. The enzymatic material may include cellulase and hemicellulase. Moreover, the enzymatic material may further include an enzyme selected from the group consisting of endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

[0027] Also, the enzymatic material may further include endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase. The strength agent may further include a dry strength agent. The dry strength agent may be selected from the group consisting of starch, polyacrylamide, guar, locust bean gums, and carboxymethyl cellulose. Furthermore, the strength agent may include a wet strength agent. The wet strength agent may be selected from the group consisting of polyamide-epichlorohydrin, polyacrylamides, styrenebutadiene latexes, insolubilized polyvinyl alcohol, urea-formaldehyde, polyethyleneimine, and chitosan polymers.

[0028] The present invention also includes a paper made from pulp modified by an enzymatic material at a storing stage of a papermaking process. The pulp may be further modified by adding a strength agent to the pulp at the storing stage. The enzymatic material may include cellulase and hemicellulase. Furthermore, the enzymatic material may further include an enzyme selected from the group consisting of endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase. Moreover, the enzymatic material may also include endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

[0029] The strength agent may further include a dry strength agent. What is more, the dry strength agent may be selected from the group consisting of starch, polyacrylamide, guar, locust bean gums, and carboxymethyl cellulose. In addition, the strength agent may include a wet strength agent. The wet strength agent may be selected from the group consisting of polyamide-epichlorohydrin, polyacrylamides, styrenebutadiene latexes, insolubilized polyvinyl alcohol, urea-formaldehyde, polyethyleneimine, and chitosan polymers.

[0030] Another embodiment of the present invention is a paper prepared from a pulp modified with an enzymatic material and having a greater solids content after being formed on a forming fabric than a paper not modified with an enzymatic material.

[0031] A further embodiment of the present invention is a paper prepared from a pulp modified with an enzymatic material and having a faster drop absorbency compared to a paper not modified with an enzymatic material. Moreover, the paper may have higher permeability, higher Z wicking, and greater water capacity than a paper not modified with an enzymatic material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a schematic diagram of a process for making a paper product of the present invention.

[0033] FIG. 2 is a front, elevational view of a permeability tester.

[0034] FIG. 3 is a graphical depiction of data comparing the drop absorbency versus refiner revolutions for four treatments applied to handsheets.

[0035] FIG. 4 is a graphical depiction of data comparing the specific volume versus tensile index for four treatments applied to handsheets.

[0036] FIG. 5 is a graphical depiction of data comparing the tensile index versus refiner rotator revolutions for four treatments applied to handsheets.

[0037] FIG. 6 is a graphical depiction of data comparing the tensile index versus refiner rotator revolutions for four treatments applied to handsheets.

[0038] FIG. 7 is a graphical depiction of data comparing the drop absorbency versus tensile index for four treatments applied to handsheets.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0039] Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to FIG. 1, there is depicted a schematic process for forming a paper product. The process includes the stages of pulping 20, storing 40, and paper forming 60.

[0040] The pulping stage 20 processes cellulosic material into pulp using any suitable means understood by those of ordinary skill in the art, such as mechanical pulping, thermomechanical pulping, chemical-thermomechanical pulping, bleached-chemical-thermomechanical pulping, or any variations thereof. The pulping stage increases the surface area of the fibers and promotes greater fiber-to-fiber bonding and strength development, which increases the strength of the subsequently formed paper. During mechanical pulping, a refiner having rotating blades may be used to cut, split, and bruise the fibers of cellulosic material to expose greater amounts of fiber surface area. Increasing the speed of the rotating blades further reduces the cellulosic material creating greater surface area, which will in turn promote the formation of stronger paper products.

[0041] It is anticipated that wood cellulosic material in all its varieties will normally comprise the paper making fibers used in this invention. Such cellulosic material may include hardwoods and softwoods. Hardwoods include the woody substance of deciduous trees (angiosperms) and softwoods include the woody substance of coniferous trees (gymnosperms). However, other cellulose materials, such as cotton liners, bagasse, and rayon, may also be used. Furthermore, fibers derived from recycled paper, which may contain any or all of the above categories as well as other non-fibrous materials such as fillers and adhesives, may be used for making paper.

[0042] After the cellulosic material is converted into pulp, it is sent to the storing stage 40 prior to papermaking. Generally, the pulp is agitated during storing to create a substantially homogeneous mixture, but no further refinement occurs.

[0043] The enzymatic material and strength agents may be added at the storing stage 40 and held at conditions appropriate for enzyme activity. Generally, the enzymatic material is added to convert crystalline cellulose to a more amorphous form. Although the Applicants do not want to be held to any one theory, it is believed that modifying the pulp from crystalline to amorphous form will create a more homogenous pulp mixture. This mixture may result in softer, and more bulky and absorbent paper products.

[0044] The enzymatic material may include cellulase, hemicellulase, cellobiohydralase, and cellobiase. Cellulases are enzymes that degrade cellulose into smaller fragments, primarily glucose, and include endocellulase and exocellulase. Endocellulase may hydrolyze the beta (1-4) bonds randomly along the cellulose chain and exocellulase may cleave off glucose molecules from one end of the cellulose strand.

[0045] Hemicellulase are enzymes that degrade hemicellulose into fragments, such as the sugars xylose, mannose, and galactose and include endohemicellulase and exohemicellulase. Endohemicellulase randomly cleave the interior bonds of the hemicellulose chain. Many different types exist, which are specific to the different sugar backbones. Exohemicellulase systemically hydrolyze the nonreducing end of the hemicellulose chain. In particular, hemicellulase enzymes include esterase, xylase, mannase, glucuronidase, and galactase.

[0046] Cellobiohydrolase enzymes systematically cleave cellobiose from the nonreducing end of a cellulose chain, while cellobiase enzymes cleave cellobiose into two glucose molecules. Cellobiohydrolase enzyme preparations may be produced by growing suitable organisms known to produce cellulase. The organisms may be bacteria, fungi, or mold. Organisms producing cellulase include:

[0047] Trichoderma, as an example T. reesei; Aspergillus, as an example A. niger; Fusarium; Phanerochaete, as an example P. chrysosporium; Penicillium, as an example P. janthinellum and P. digitatum; Streptomyces, as an example S. olivochromogenes and S. flavogriseus; Humicola, as an example H. insolens; Cellulomonas, as an example C. fimi; Bacillus, as an example B. subtilis and B. circulans; Phlebia; Ceriporiopsis; and Trametes.

[0048] One exemplary enzymatic material may include a mixture of cellulase and hemicellulase produced by submerged fermentation of the fungus Humicola insolens. The main activities of the material are endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase. This material is manufactured under the trade designation NOVOZYM 342 by Novo Nordisk Bioindustrials, Inc., 33 Turner Road, Danbury, Conn. 06313-1907. Desirably, about 0.005 to about 2.0 weight percent of enzymatic material is added to the pulp. More desirably, about 0.10 weight percent of enzymatic material is added to the pulp.

[0049] Strength agents may include wet and dry strength agents. Wet strength agents may include polyamide-epichlorohydrin, polyacrylamides, styrenebutadiene latexes, insolubilized polyvinyl alcohol, urea-formaldehyde, polyethyleneimine, and chitosan polymers. One commercial source of a useful polyamide-epichlorohydrin resins is Hercules, Inc. of Wilmington, Del., which markets such resin under the trade-designation KYMENE 557H or KYMENE 557LX. Desirably, about 0.005 to about 2.0 weight percent of wet strength agent is added to the pulp. More desirably, about 0.6 weight percent of wet strength agent is added to the pulp.

[0050] Dry strength agents may include starch, polyacrylamide, guar, locust bean gums, and carboxymethyl cellulose. One commercial source of a useful carboxymethyl cellulose is Hercules, Inc. of Wilmington, Del., which markets such agent under the trade-designation CMC. Desirably, about 0.005 to about 2.0 weight percent of dry strength agent is added to the pulp. More desirably, about 0.05 to about 1.0 weight percent of wet strength agent is added to the pulp.

[0051] The storing stage 40 may include a blend mix tank 44, a save-all chest 48, a machine chest 52, and a stuffbox 56, although other combinations may be used. Desirably, the enzymatic material is added at the blend mix tank 44, the wet strength agent is added at the machine chest 52, and the dry strength agent is added at the stuffbox 56, although they may added anywhere at the storing stage 40. Alternatively, the paper may be made without strength agents by only adding the enzymatic material at the storing stage 40. Desirably, the enzymatic material is added to the pulp fibers prior to the addition of the strength agents. Desirably, the retention time of the enzymatic material is from about 25 to about 40 minutes and the temperature, as well as other conditions, should be held at conditions that promote enzyme activity.

[0052] The pulp is transferred from the storing stage 40 to the papermaking stage 60. Any suitable papermaking process may be used, but some exemplary papermaking processes using uncreped-through-air-dried and straight rush transfer technologies are disclosed by U.S. Pat. Nos. 5,048,589, 5,348,620, 5,501,768, 5,399,412, 5,429,686, and 5,725,734, which are hereby incorporated by reference.

[0053] A couple of examples are provided illustrating paper samples made according to the present invention along with experimental data. The basis weight of the samples was used to calculate some of the values in the following tables. Both examples used basis weights determined in the following manner.

[0054] The following method was used to calculate mass per unit area (basis weight) of specimens, which do not require conditioning. A specimen of pre-determined size was cut from the sample material and the basis weight of the specimen was calculated from its weight and area.

[0055] The following materials were used: a balance, standard weights, a level, a weighing pan, a cutting press, dies, and a ruler. The balance had a capacity and sensitivity to weigh to about 0.001 gram (g) for specimens weighing under about 10 g and about 0.01 g for specimens weighing about 10 g and over. One exemplary balance is sold under the trade designation OHAUS™ GT210 by VWR Scientific Products of South Plainfield, N.J. The standard weights had a range from about 10 milligram (mg) to about 100 g. Exemplary standard weights may be obtained from VWR Scientific Products. If a level was not supplied with the balance, than desirably a sealed glass vial was utilized. The weighing pan was of a size large enough to hold the specimen and to prevent the specimen from hanging over the pan. Desirably, the minimum die size for a single specimen will be 4.5±0.1 inch (in.) by 4.5±0.1 in. (114±3 millimeter (mm) by 114±3 mm). However, if multiple smaller specimens were used to meet the minimum area desired, then any known size die would be appropriate. The ruler was graduated in 0.1 in. or 1 mm increments.

[0056] Test specimens were obtained from areas of the sample that were free of folds, wrinkles, or any distortions making these specimens abnormal from the rest of the test material. Desirably, all specimens had a minimum area of at least 20 in.2 (130 cm2) or a number of smaller die-cut specimens were taken from different locations in the sample with a minimum total area of 20 in.2 (130 cm2). The specimens were prepared by cutting within ±1% of the desired size, (e.g., a specimen cut 20 in.2 will have an allowable tolerance of ±0.2 in.2). Consequently, the completed data should include the size of the specimen measured if not specified in the product specifications. Furthermore, the procedure prevented dirt or other foreign material on the specimen. A minimum of three random specimens were tested for each material for deriving a mean basis weight.

[0057] Each specimen was weighed with the following procedure. After the calibrating the balance, the weighing pan was placed on the balance and the balance tared. The specimen was placed in the weighing pan so no portion of the specimen hung over the edge of the balance. The weight of the specimen was recorded to the nearest 0.001 gram if the specimen weighed less than 10 g and to the nearest 0.01 gram if the specimen weighed 10 g or more.

[0058] The basis weight of the samples were calculated by first determining the area of the sample in square inches. Unknown specimen areas were determined by measuring the length and width to the nearest 0.01 in. Afterwards, the weight of the specimen measured in grams was divided by the area. This value was multiplied by a factor to obtain the desired units. The following formulas and factors were used to calculate the basis weight:

Area of specimen (in.2)=Length×Width

[0059] Calculation of basis weight:[Weight(g)/Area]xFactor Conversion factors:

[0060] g/m2=1550

[0061] g/yd2=1296

[0062] lb/2880 ft2=914.31

[0063] oz/yd2=45.72

EXAMPLE 1

[0064] The following are examples of handsheets made at various refinement rates and with different additive combinations. Four batches of pulp were created by mechanically refining sulfite bleached softwood produced from a Kimberly-Clark Corp. mill at Everett, Washington at four different rotator revolutions, namely, 100, 500, 1000, and 2000 revolutions. Afterwards, each batch was mixed with about 10 weight percent of BCTMP sold by Miller Western Corp. located at Edmonton, Alberta, Canada.

[0065] Next, portions from each batch were separated and treated with one of four additive treatments having different combinations of enzymatic material and/or strength agents as depicted below in Table 1. 1 TABLE 1 Materials Included In The Treatment Treatment Number NOVOZYM 342 KYMENE CMC 1 no yes no 2 no yes yes 3 yes yes no 4 yes yes yes

[0066] The enzymatic material used was about 0.1 weight percent of a NOVOZYM 342 enzymatic material, the wet strength agent used was about 0.6 weight percent of a KYMENE agent, and the dry strength agent used was about 0.15 weight percent of a CMC agent. The weight percent of these additives was in relation to the total weight of the pulp mixture. During additive treatment, the mixtures were maintained at a temperature of about 43 degrees Celsius, a pH between about 6.5 to 7.5, a consistency of about 3 percent, and agitated for about 35 minutes. The reaction time of the enzymatic material was about 35 minutes, the reaction time of the wet strength agent was about 10 minutes, and the reaction time of the dry strength agent was about 5 minutes.

[0067] Afterwards, ten handsheets were prepared from each treated pulp. The handsheets were prepared by pressing about 45 gsm of pulp for about 30 seconds at about 308 kiloPascals.

TESTS

[0068] The prepared handsheets were subjected to several tests, namely, specific volume, tear index, tensile index, Frazier Porosity, and absorbency. All test data points except absorbency in Table 2 were calculated by taking the mean of ten sample results. Absorbency was calculated by taking the mean of five sample results.

[0069] The specific volume was determined by measuring the thickness of the paper and dividing by the measured paper's basis weight. The thickness of the paper was determined with a procedure conforming essentially to TAPPI Standard T 411 om-89. The procedure deviated from the TAPPI Standard by measuring the thickness of five specimens rather than ten TAPPI specimens and conducting three measurements rather than five TAPPI measurements.

[0070] The tear index was calculated by dividing the tearing load by the sample basis weight. The tearing load measures the toughness of a material by measuring the work required to propagate a tear when part of a specimen is held in a clamp and an adjacent part is moved by the force of a pendulum freely falling in an arc.

[0071] The following method was used to determine the tearing load of the handsheets. This method determined the average force required to propagate a tear starting from a cut slit in the material being tested. The higher the number, the greater the force to tear the specimen.

[0072] This procedure is specific to a falling-pendulum (Elmendorf-type) instrument. Desirably, the tester is equipped with a pendulum that has a deep cutout (recessed area) on the pendulum sector and pneumatically-activated clamps. The tester used was sold under the trade designation Lorentzen and Wettre brand, Model O9ED. This tester may be obtained from Lorentzen Wettre Canada Inc., Fairfield, N.J. 07004.

[0073] In addition to the tester, a specimen cutter was used capable of providing 63.0±0.15 mm (2.5±0.006 in.) specimens. It is recommended that the specimens be cut no closer than 15 mm from the edge of the material and the specimens be taken only in areas that are free from folds, creases, and crimp lines. The handsheet specimens were cut to 63±0.15 mm by 73±1 mm and placed facing up in the same direction. Additional equipment included a 50 g weight.

[0074] No conditioning of specimens was conducted prior to testing. The tests were conducted in a standard laboratory atmosphere of 23±1° C. (73.4±1.8° F.) and 50±2% relative humidity.

[0075] The number of plies needed for the test results to fall between 20 to 60 on the linear range scale of the tear tester was determined. The 63 mm length of the handsheet specimens was run vertically on the tear tester.

[0076] The tester was placed a level surface free from noticeable vibrations and leveled. Afterwards, testing of a specimen was begun by verifying that the power was on. Next, the rotary dial was set to the number of plies to be torn. That being done, the number button was pushed and the cutting lever was pushed down. Afterwards, the digital readout was verified as correct. Next, the specimen was placed between the clamps with the edge of the specimen aligned with the front edge of the clamp. If more than one sheet was tested, the sheets were placed facing in the same direction. That being done, the clamp button was pushed to close the clamps. Afterwards, a slit was cut in the specimen by pushing down on the cutting knife lever until it reaches its stop. The slit was clean with no tears or nicks. Next, the pend button was pushed to release the pendulum. That being done, the pendulum was caught on the back swing and positioned to the starting position after the pendulum traveled one full swing. Afterwards, the pend button was depressed to raise the stop once the pendulum was behind it. The value was recorded unless the tear line deviated more than 10 millimeters. If the deviation was more than 10 millimeters, the specimen was discarded and a new specimen tested.

[0077] The results were recorded in grams centimeter. The values were reported to the nearest whole number. The following conversion factors were used with units which had a 1600-gram capacity and did not automatically convert the test result: 2 # of multiply sheets by  1 sheet 16  2 sheets 8  4 sheets 4  5 sheets 3.2  8 sheets 2 10 sheets 1.6 12 sheets 1.33 16 sheets 1

[0078] Tensile index of samples was calculated by dividing the sample tensile strength by the sample basis weight. Tensile strength refers to the maximum load or force (i.e., peak load) encountered while elongating the sample to break. The tensile strength was determined with an Instron Model 1122 Universal Test Instrument in accordance with Test Method TAPPI T 404 cm-82. Each sample was about 2.54 centimeters wide and the initial separation between the tester jaws prior to elongation was about 12.7 centimeters.

[0079] The following test was used to determine the air permeability of the handsheets, which was expressed as cubic feet of air per minute per square foot (ft3/ft2×in). The air, which was drawn through the fabric by a given suction, was measured with an orifice-type flowmeter.

[0080] The equipment utilized in the test included a Frazier Permeability Tester manufactured by Frazier Precision Instrument Co. of 925 Sweeney Dr., Hagerstown, Md. 21740. An exemplary Frazier Permeability Tester 100 is depicted in FIG. 2 and includes an inclined manometer frame 144. The frame 144 includes an inclined manometer 124, screws 128, a spirit level 130, and a micrometer plunger 132. The tester 100 also includes fabric test opening 110, a beveled ring 112, a clamp 114, a front portion 116, a motor 118, a suction fan 120, a dial 122, a vertical manometer 134, an air orifice sizer 138, a sliding scale 142, and a specimen clamp 148. The specimen clamp 148 has a bottom portion 150 and a top portion 152.

[0081] During the testing, the beveled ring 112 was placed over a specimen to hold it in a smooth condition and with a slight tension in all directions across the fabric testing opening 110. The area of this opening 110 was about 38.3 cm2 (6.99 cm in diameter). The ring 112 was hinged at the back of the table and locked in the front portion 116. The motor 118, which drove the suction fan 120, was adjusted by the dial 122. The manometers 124 and 134 were filled with Merriam Red oil having a specific gravity 0.827, and used to indicate the pressure drop across the test piece and across the orifice 138 for measuring the air-flow. The inclined manometer 124, which indicated the pressure drop across the test place, was provided with leveling screws 128 and spirit level 130.

[0082] Other equipment used included a flow rate calibration chart, a test plate for calibrating the equipment, and air orifices, having diameters of 1.0, 1.4, 2.0, 3.0, 4.0, 6.0, 8.0, 11.0, and 16.0 millimeters, and Merriam Red oil refill having a specific gravity of 0.827. These items may be obtained from Frazier Precision Instrument Co of 925 Sweeney Dr., Hagerstown, Md. 21740 as well. Additional equipment included a spirit level.

[0083] Tests were conducted in a standard laboratory atmosphere of 23±2° C. (73.4±3.6° F.) and 50±5% relative humidity. A single ply of the specimens was tested. Opening and closing the doors in the permeability tester room was minimized because these actions may cause the manometers 124 and 134 to fluctuate erratically.

[0084] Prior to testing, several set-up measures were undertaken besides calibrating the tester 100. First, the dial 122 was turned all the way in a counterclockwise direction before plugging the unit in or turning the unit on. Second, the oil level was verified at zero with the suction off in the vertical manometer 134. Third, the sliding scale 142 was adjusted to obtain the proper zero setting. Fourth, the oil level in the inclined manometer 124 was verified at zero with the suction off. If needed, the micrometer plunger 132 was used to adjust the zero position. Fifth, using a spirit level, the horizontal level of the inclined manometer frame 144 was checked. If needed, the screws 128 were adjusted to obtain a level position. Sixth, the air orifice size 138 was recorded on a testing form.

[0085] The testing was conducted as follows. The bottom section 150 of the specimen clamp 148, beveled side down, was placed over the opening 110. Next, the top section 152 of the specimen clamp 148 was attached with the beveled side up to the bottom section 150. Afterward, a single-ply specimen was placed over the bottom specimen clamp 150. That being done, the specimen clamp 114 was lowered into position and held firmly in place. Next, the unit was turned on. Afterward, the dial 122 was turned slowly in a clockwise direction until the inclined manometer 124 oil column reached 0.5. The dial 122 was turned slowly when increasing the suction because a rapid increase in speed can cause the oil in the vertical manometer to overflow. If the pressure drop on the vertical manometer was less than 3 inches, a smaller orifice was used to get a drop greater than 3 inches. It is usually desirable to have a pressure drop between 5 and 20 inches.

[0086] After the inclined manometer 124 oil column had steadied at 0.5 level, the level of the oil in the vertical manometer 134 was taken and recorded on the proper form. The manometers were read at eye level to avoid errors of parallax or distorted readings. The vertical manometer reading was converted to a flow rate in units of cubic feet of air per minute per square foot of sample by using the calibration table.

[0087] The absorbency of the samples measured the rate of water drop absorption in accordance with TAPPI test method T 432 om-94, which records the times for absorption of a 0.01 mL drop of distilled water.

[0088] The results of the above tests for the sixteen handsheet samples are depicted in Table 2: 3 TABLE 2 Treatment # 1 Mill Refining Rev. 100 500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.71 2.60 2.42 2.29 Tear Index (mNm{circumflex over ( )}2/g) 10.42 8.87 8.24 7.43 Tensile Index (Nm/g) 27.86 36.36 40.22 44.97 Porosity, Frazier (cfm/ft{circumflex over ( )}2) 158.4 91.7 71.5 41.2 Absorbency (sec) 7.4 18.2 34.5 50.5 (0.01 ml) Treatment # 2 Mill Refining Rev. 100 500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.71 2.51 2.42 2.29 Tear Index (mNm{circumflex over ( )}2/g) 12.57 11.57 10.81 9.70 Tensile Index (Nm/g) 29.38 36.29 42.44 46.92 Porosity, Frazier (cfm/ft{circumflex over ( )}2) 177.4 101.5 94.5 45.3 Absorbency (sec) 8.3 14.5 36.2 55.7 (0.01 ml) Treatment # 3 Mill Refining Rev. 100 500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.87 2.48 2.39 2.35 Tear Index (mNm{circumflex over ( )}2/g) 12.01 11.25 10.35 9.68 Tensile Index (Nm/g) 27.20 37.50 39.87 44.46 Porosity, Frazier (cfm/ft{circumflex over ( )}2) 180.66 102.18 84.42 32.45 Absorbency (sec) 8.4 22.1 29.2 50.1 (0.01 ml) Treatment # 4 Mill Refining Rev. 100 500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.86 2.53 2.43 2.22 Tear Index (mNm{circumflex over ( )}2/g) 11.83 10.94 10.33 8.85 Tensile Index (Nm/g) 30.56 38.93 43.53 47.38 Porosity, Frazier (cfm/ft{circumflex over ( )}2) 163.06 117.24 79.43 32.92 Absorbency (sec) 4.5 10.0 20.5 49.1 (0.01 ml)

[0089] FIGS. 3-7 depict some of the data from Table 2. The figures illustrate that handsheets having Treatment 4 exhibit faster absorbency and higher specific volume while having slighter superior strength and toughness properties than the other treated handsheets.

[0090] In particular, FIG. 3 compares the four treatments at different refinement rates. It is clear from the graph that the handsheets having the fourth treatment exhibit faster drop absorbency than the other treated handsheets. Furthermore, FIG. 4 illustrates that the handsheets made with Treatment 4 have higher specific volume at most tensile index ranges. These graphs illustrate that Treatment 4 produces handsheets with greater absorbency and substantially greater specific volume than the other treated handsheets, which translates into greater absorbency and bulk.

[0091] Moreover, FIG. 5 depicts the fourth handsheets having slightly superior tensile index attributes at similar refinement speeds, which is a measure of strength, than the three other treated handsheets. Similarly, FIG. 6 demonstrates that handsheets made with Treatment 4 have generally the same tear index at a given tear index as the second and third treated handsheets.

[0092] Overall, handsheets made with Treatment 4 have superior absorbency and specific volume while maintaining at least the same strength and toughness as the other treated handsheets. This is readily illustrated with regard to drop absorbency by FIG. 7. The handsheets made with Treatment 4, which have been treated with enzymes, and wet and dry strength agents, clearly have faster drop absorbency at a given tensile index than the other handsheets.

EXAMPLE 2

[0093] This example compares papers made with varying additive ingredients at a paper manufacturing line. Four separate batches of paper were prepared by mixing about 27 kilograms of wet lap pine produced from a Kimberly-Clark Corp. mill at Mobile, Ala. with about 27 kilograms of recycled fiber obtained from Fox River Corp. of Appleton, Wis. for about 20 minutes in a blend mix tank. Afterwards, the temperature was raised to about 49 degrees Celsius at a pH of about 7.0. In three of the batches, about a 0.1 weight percent of NOVOZYM 342 material was added to the fibers and slushed for about two minutes and the batch was allowed to sit for about 30 minutes.

[0094] The batches were transferred from the blend mix tank to a machine chest and about 6 grams of wet strength agent per about 1000 grams of fibers was added to each batch. The wet strength agent utilized was a KYMENE agent sold under the trade designation 557LX by Hercules, Inc. Afterwards the batch was transferred to a stuff box. Optionally, a carboxy methyl cellulose dry strength agent, namely 7MT CMC agent manufactured by Hercules, Inc., was metered into the stuff box. The CMC agent was added at a concentration of about 0.88 weight solution to the furnish in the stuffbox. This produced a residence time of about 2.3 minutes.

[0095] All batches included the KYMENE agent, but the batches included different amounts of NOVOZYM 342 material and CMC agent. Table 3 depicts the amounts used in each batch: 4 TABLE 3 NOVOZYM 342 CMC BATCH (weight percent) (g CMC/kg pulp) 1 0.0 0 2 0.1 0 3 0.1 1 4 0.1 2

[0096] Each batch was processed into paper sheets by an uncreped-through-air-dried process. The sheets from the batches were subjected to several tests. The machine direction peak load and GMBL measured the strengths of the samples. The wicking and water capacity tested the absorbency levels of the samples. The permeability measured the amount of air-flow that will pass through a material at given conditions per unit of time.

TESTING

[0097] The following test method was used to determine the tensile strength of the paper sheets. The equipment included a constant rate of extension (CRE) unit along with an appropriate load cell and computerized data acquisition system. An exemplary CRE unit is sold under the trade designation SINTECH 2 manufactured by Sintech Corporation, whose address is 1001 Sheldon Drive, Cary, N.C. 27513. The type of load cell was chosen for the tensile tester being used and for the type of material being tested. The selected load cell had values of interest fall between the manufacturer's recommended ranges of the load cell's full scale value. The load cell and the data acquisition system sold under the trade designation TestWorks™ may be obtained from Sintech Corporation as well.

[0098] Additional equipment included pneumatic-actuated jaws, weight hanging brackets, and precision sample cutter. The jaws were designed for a maximum load of 5000 g and may be obtained from Sintech Corporation. The weight hanging brackets included a flat bracket and an “L” shaped bracket. These brackets were inserted into the jaws during calibration or set-up. A precision sample cutter was used to cut samples within 3±0.04 inch (76.2±1 mm) wide. An exemplary sample cutter is sold under the trade designation JDC by Thwing Albert Instrument Co., of Philadelphia, Pa.

[0099] Tests were conducted in a standard laboratory atmosphere of 23±2° C. (73.4±3.6° F.) and 50±5% relative humidity. The two principal directions, machine and cross, of the material was established. The specimens had a width of about 3 in (7.62 cm) and a length in the testing jaws of about 4 in (10.2 cm). The length of the specimen was chosen either in the cross or machine direction of the material being tested for determining either the cross or machine direction tensile. Desirably, the length was cut approximately 1.5 inches longer than the jaw spacing used for the test and the test specimens were free of tears or other defects, and had clean cut, parallel edges.

[0100] The tensile tester was prepared as follows. A load cell was installed for the type of tensile tester being used and for the type of material being tested. A load cell was selected so the values of interest fell between the manufacturer's recommended ranges of the load cell's full scale value. The separation speed of the jaws was set at 10±0.4 inches/minute (25.4±1 cm/minute). The break sensitivity was set at a 65% drop from the peak. Furthermore, the slack compensation was set at 25 grams and the slope preset points were set at 70 and 157 grams. The threshold was set at 2% of the full scale load. Additionally, the jaws were installed on the tester and the tester calibrated by the manufacturer's instructions for the particular tensile tester/software being used.

[0101] The testing procedure began by inserting the specimen centered and straight into the jaws. Next, the jaws extending across the specimen's width were closed while simultaneously excessive slack was removed from the specimen. Afterward the machine was started and the jaws separated. The test ended when the specimen ruptured. That being done, the results were recorded.

[0102] Once the tensile strength of the specimens were determined in the machine and cross direction, it was important to compensate for the differences in basis weight of the samples and for machine directional differences in tensile strength. Compensation was achieved by calculating a geometric mean breaking length, which is abbreviated “GMBL”. GMBL is calculated as the quotient obtained by dividing the basis weight into the square root of the product of the machine direction and cross machine direction tensile strengths.

[0103] When English units of measurement are used, tensile strength is measured in ounces per inch and basis weight in pounds per ream (2880 square feet). When calculated in metric units the tensile strength is measured in grams per 7.62 centimeters and the basis weight is measured in grams per square meter. It should be noted that the metric units are not pure metric units because the test apparatus used for testing tensile is set up to cut a sample in inches and accordingly the metric units comes out to be grams per 3 in. (7.62 cm). Using the abbreviations MDT for machine direction tensile, CDT for cross machine direction tensile and BW for basis weight, the mathematical calculation of the GMBL is:

GMBL=(MDT×CDT)½/BW

[0104] GMBL in English units=0.060 ×the GMBL in the above defined metric units.

[0105] The following method was used to determine the absorption capacity of the paper products. Equipment items utilized were a capacity tester stand, a water pan, a supply of purified water, a precision electronic balance, a weighing dish, a stopwatch, a pair of forceps, paper toweling, hanging clamps, a cutting device, and a thermometer. The pan was large enough to hold water to a depth of at least (5.08 cm) two inches. The supply of purified water was distilled or deionized and at a standard laboratory temperature of 23±2° C. (73.4±3.6° F.). The balance was capable of weighing accurately to about 0.01 g. An exemplary balance is sold under the trade designation OHAUS™ GT480 by VWR Scientific Products of South Plainfield, N.J. The weighing dish was large enough to hold the specimen. The stopwatch was accurate and readable to 0.1 seconds. An exemplary cutting device is sold under the trade designation TMI DGD by Testing Machines, Inc., Amityville, N.Y. 11701. The die used with this device had dimensions of 4 in. by 4 in. ±0.01 in. (10.16 cm by 10.16 cm ±0.25 cm). The thermometer was readable to 1.0 ° C.

[0106] Tests were conducted in a standard laboratory atmosphere of 23±2° C. (73.4±3.6° F.) and 50±5% relative humidity. The handling of specimens was minimized to reduce biasing the test results. The test specimens were taken from areas of the sample free of folds, wrinkles, or any distortions, which might have made these specimens abnormal from the rest of the test material. Specimens were cut from one sheet to the dimension of 4.0 in. by 4.0 in. ±0.10 in.(10.16 cm by 10.16 cm ±25 cm).

[0107] The testing was performed on a level, solid surface free from noticeable vibrations. The balances were allowed the appropriate warm-up time and tared. Next, the pan was filled with water to a depth of at least 2 in. (5.08 cm) and a temperature of 23±20° C. (73.4±3.6° F.).

[0108] Each specimen was numbered and weighed and the weight recorded to the nearest 0.01 gram. Next the stopwatch was started, and simultaneously, the specimen was placed in the pan of water. The specimen was soaked for 3 minutes ±5 seconds. At the end of the specified time, the specimen was removed by the forceps and attached to a hanging clamp. The specimen hung in a “diamond” shape position ensuring the proper flow of fluid from the specimen. In addition, the specimen was hung in a chamber having 100 percent relative humidity for 3 minutes ±5 seconds.

[0109] Next, the weighing dish was placed on the balance and tared. Afterward, the weighing dish was brought below the hanging specimen and the clamp was released allowing the specimen to fall into the weighing dish. That being done, the weighing dish and specimen were placed on the balance and weighed. The weight was recorded to the nearest 0.01 gram. Finally, the wet specimen was discarded and the weighing dish wiped dry.

[0110] Calculations were made as follows. Individual dry and wet weights were recorded for each specimen to the nearest 0.01 gram. Thus, the absorption capacity of each specimen was calculated to the nearest 0.01 gram as follows:

Absorbent Capacity (g)=Wet weight (g)−Dry weight (g)

[0111] The wicking test involved clamping a specimen and raising a water bath until it contacts the specimen. An Anderson-Ross Wicking testing machine, such as those manufactured by Micro Labs, whose address 18E Eagle Road, Havertown Pa., is used to measure the XY-direction or horizontal plane and the Z-direction or vertical plane. The wicking is based upon the amount of water absorbed in a given direction by the specimen within an 18 second time period.

[0112] Substantially circular specimens having a diameter of about 8.5+/−0.010 centimeters and a thickness ranging from about 0.58 to 0.69 millimeter were taken from the tissue products produced as described above.

[0113] Five specimen samples were tested by above-described testing for each product. Thus, each data point in Tables 4 and 5 represents the mean of the five samples.

[0114] Table 4 depicts the mean strength of the samples for each batch below: 5 TABLE 4 DRY TENSILE g/3 inches GMBL Batch MD CD m 1 7403 5564 1985 2 7071 5198 1782 3 6700 5554 1918 4 7351 5698 2057

[0115] As can be seen, the samples treated with an enzyme and wet and dry strength agents (Batch 4) exhibit higher mean breaking length than the control sample and the sample treated only with the enzyme (Batches 1 and 2).

[0116] Table 5 depicts the absorbency and permeability for each batch below: 6 TABLE 5 Z Water Capacity Wicking XY Wicking Permeability Batch g/g g/g/sec g/g/sec cfm/38 sq. cm 1 4.00 3.37 1.18 55.6 2 4.16 5.03 1.17 72.4 3 4.28 4.09 1.52 72.4 4 4.18 4.45 1.24 72.3

[0117] As can be seen in Table 5, the enzymatic samples from batches 2, 3, and 4 exhibit higher capacity, and z wicking, thereby illustrating higher absorbency than the control batch 1. The enzymatic and dry agent treated batches 3 and 4 exhibit even higher absorbency, as illustrated by the results in the water capacity and XY wicking. It should be also noted that the enzymatic batches 2 and 3 show higher permeability than the control batch 1.

EXAMPLE 3

[0118] Paper rolls were made in accordance to the procedure previously described in Example 2. A control paper roll, which was made in substantially the same manner as Batch 1 from Example 2, was compared with an enzymatic paper roll, which was made in substantially the same manner as Batch 2 from Example 2. Table 6 compares the two rolls with respect to the percent solids after vacuum dewatering, but prior to through-drying as exemplified in U.S. Pat. No. 5,048,589, which was incorporated by reference. 7 TABLE 6 Control Enzymatic Rolls Roll Treated Roll Percent Solids after forming fabric transfer 34% 40% Grams of Water/Grams of Pulp 1.94 1.50

[0119] The difference in the grams of water per grams of pulp in the control and enzymatic treated rolls results in a reduction of the evaporation load of about 23%. This value was calculated by the following formula:

Reduction in evaporation load=((1.94−1.50)/1.94)*100

[0120] Thus, about 23 percent less energy will be needed to dry the enzymatic sheet to 95% solids. Consequently, the enzymatic treated roll will save energy during papermaking.

[0121] While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims.

Claims

1. A process for making paper comprising the step of adding an enzymatic material at a storing stage of a papermaking process to modify the pulp.

2. The process of claim 1 further comprising the step of:

adding a strength agent to pulp at the storing stage.

3. The process of claim 1 wherein the enzymatic material further comprises cellulase and hemicellulase.

4. The process of claim 1 wherein the enzymatic material further comprises an enzyme selected from the group consisting of endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

5. The process of claim 1 wherein the enzymatic material further comprises endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

6. The process of claim 2 wherein the strength agent further comprises a dry strength agent.

7. The process of claim 6 wherein the dry strength agent is selected from the group consisting of starch, polyacrylamide, guar, locust bean gums, and carboxymethyl cellulose.

8. The process of claim 2 wherein the strength agent further comprises a wet strength agent.

9. The process of claim 8 wherein the wet strength agent is selected from the group consisting of polyamide-epichlorohydrin, polyacrylamides, styrenebutadiene latexes, insolubilized polyvinyl alcohol, urea-formaldehyde, polyethyleneimine, and chitosan polymers.

10. A paper made from pulp modified by an enzymatic material at a storing stage of a papermaking process.

11. The paper of claim 10 wherein the pulp is further modified by adding a strength agent to the pulp at the storing stage.

12. The paper of claim 10 wherein the enzymatic material further comprises cellulase and hemicellulase.

13. The paper of claim 10 wherein the enzymatic material further comprises an enzyme selected from the group consisting of endo-glucanase, cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

13. The paper pf claim 10 wherein the enzymatic material further comprises ebdi-glucanase. cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

14. The paper of claim 11 wherein the strength agent further comprises a dry strength agent.

15. The paper of claim 11 wherein the strength agent further comprises a wet strength agent.

16. A paper prepared from a pulp modified with an enzymatic material and having a greater solids content after being formed on a forming fabric than a paper not modified with an enzymatic material.

17. A paper prepared from a pulp modified with an enzymatic material and having faster drop absorbency compared to a paper not modified with an enzymatic material.

18. The paper of claim 17 prepared from a pulp modified with an enzymatic material wherein the paper has a higher permeability than a paper not modified with an enzymatic material.

19. The paper of claim 18 prepared from a pulp modified with an enzymatic material wherein the paper has a higher Z wicking than a paper not modified with an enzymatic material.

20. The paper of claim 19 prepared from a pulp modified with an enzymatic material wherein the paper has a greater water capacity than a paper not modified with an enzymatic material.