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    • 专利摘要:
    FILAMENTS INCLUDING MICROFIBRILLARY CELLULOSE, FIBROUS NON-WOVEN WEAVES AND PROCESS TO MANUFACTURE THEM. Disclosed herein is a cellulosic textile filament made from microfibrillar cellulose fibers and a thickening agent as well as the precursor absorbent material to form such filaments, nonwoven webs made from such cellulosic textile filaments and the process for forming such filaments and wefts of non-woven fabrics that include such filaments. One of the advantages of these filaments is the eco-friendly way in which they are manufactured as they use a water-based absorbent material that does not require any chemical solvents unlike other processes such as those used to make Lyocell fibres. Furthermore, the process does not involve any washing or extraction steps and employs a cellulosic fiber source that is largely based and renewable.
    公开号:BR112015009359B1
    申请号:R112015009359-0
    申请日:2013-10-22
    公开日:2021-07-06
    发明作者:David M. Jackson；Christopher O. Luettgen
    申请人:Kimberly-Clark Worldwide, Inc；
    IPC主号:
    专利说明:

    [001] This patent application claims the priority benefit of Provisional Patent Application No. 61/720,510 filed on October 31, 2012. HISTORY OF THE INVENTION
    [002] The present invention relates to the field of manufacturing and using cellulose filaments from renewable resources as well as products including such filaments.
    [003] Energy and resource conservation is an ever-increasing area of focus. Energy costs continue to rise and many material sources such as petroleum-based materials are under constant cost and availability concerns. One area where this is particularly true is for disposable and semi-durable goods, especially in the area of consumer products used for personal, home and commercial applications.
    [004] The daily routine of today's consumer often involves the use of products that are single-use products or products that are used only a few times before being discarded. Non-limiting examples of such products include, but are not limited to, absorbent articles for personal care, hygiene-related products and cleaning products for home, business and commercial applications. Examples of absorbent personal care articles include, but are not limited to, diapers, diaper pants, workout pants, feminine hygiene products, adult incontinence devices, wet and dry wipes, bandages, and the like. Hygiene-related products include, but are not limited to, wipes, make-up wipes and sanitary pads. Cleaning products include, but are not limited to, household wipes and towels, paper towels, mop covers, etc.
    [005] Many of the above products and other products utilize petroleum-based materials such as polyolefin and other polymer-based filaments which are employed in the manufacture of fibrous non-woven webs that are used to absorb and/or release liquids. For example, many of the layers in absorbent personal care articles are made from polymer-based fibrous non-woven fabrics.
    [006] An effort has taken place to manufacture such filaments and nonwovens from sustainable resources and to move away from other petroleum-based products. One area has been concerned with the manufacture of such filaments and non-wovens from renewable raw materials that are based on cellulose. A known method is referred to as the Lyocell process which is one of many examples of processes that require chemical solvents (N-methylmorpholine N-oxide) to dissolve the cellulose and allow it to be formed into a fiber. Once the fiber is formed, other chemicals such as amine oxide are used to set the fiber after which the fibers must be washed in water to remove the forming chemicals. Obviously this involves many processing steps, the use of additional chemicals which involve higher cost to use, extract and recycle as well as potential environmental issues relating to the use and disposal of the chemicals used in the process. It would be, therefore, desirable to have a more simplified process that would involve a smaller number of steps, the use of fewer chemicals and therefore, a lower cost in the context of manufacturing. The present invention is intended for an effort of this nature. SUMMARY OF THE INVENTION
    [007] It is disclosed in this document a cellulosic textile filament that uses microfibrillar cellulose that is produced with few chemical additives from a water-based process that is simplified in its components and manufacturing process steps. Unlike other processes like the Lyocell process mentioned above, there is no need to use chemicals such as N-methylmorpholine N-oxide to dissolve the cellulosic source in order to produce an extrudable fiber absorbent material which, after Formation needs to be subjected to the use of additional chemicals and subsequent extraction and/or washing processes to remove the chemicals used in the initial part of the fiber formation process. Consequently, the process of the present invention is more of a physical process than a chemical/dissolution process, as is the case with, for example, the Lyocell process. In addition, microfibrillar cellulose can be manufactured from an almost infinite number of plant cellulosic resources, all of which are renewable and in some cases the by-product of other cellulose-based processes. As a result, filaments, fibrous non-woven webs and end products can be manufactured from a fully renewable resource with fewer steps and fewer chemicals. This means that the materials generated through the present invention may be suitable candidates for substitution in a number of products that currently depend on non-woven fibers and fibrous webs that are based on petroleum and other non-renewable bases.
    [008] The filaments of the present invention are manufactured from a cellulosic textile filament precursor absorbent material which is comprised, based on the total weight of the precursor absorbent material, from about 7 to about 20 percent by weight of microfibrillary cellulose fibers about 0.2 to about 3 percent by weight of a thickening agent and about 75 to about 95 percent by weight of a water-based solvent. Microfibrillar cellulose fibers are dispersed in the water-based solvent while the thickening agent is dissolved in the solvent. The precursor absorbent material should have a dynamic viscosity ranging from about 400 to about 3000 Pascal seconds at a shear rate of 100 seconds reciprocal.
    [009] In certain applications, other components including, but not limited to, binding agents, both physical and chemical, may be added to the precursor absorbent material to improve the integrity of the resulting filaments formed from the absorbent precursor material.
    [0010] Once formed, in one application the cellulosic textile filament may comprise, based on the total dry weight of the filament, from about 80 to about 99.5% by weight of microfibrillary cellulose fibers and about 20 to about 0.5 percent by weight of a thickening agent. When calculating dry percentages on formed filaments, the percentages are based on the total weight of the dry ingredients and exclude any residual moisture. Thus, for example, if a filament or sample has a total weight of 110 grams including 80 grams of microfibrillary cellulose, 20 grams of a thickening agent and 10 grams of residual moisture, the dry weight percentages would be 80% by weight of microfibrillary cellulose. and 20% by weight thickening agent.
    [0011] In an alternative application, the cellulosic textile filament may comprise, based on the total dry weight of the filament, from about 75 to about 99% by weight of microfibrillary fibers, from about 20 to about 0.5 per percent by weight of a thickening agent and from 0.5 to about 5 percent of other components. An example of another component is a binding agent.
    The filaments thus formed will generally have a diameter in the dry state of between about 5 and about 50 microns. Filament lengths can be varied to meet the need for a specific purpose. Filaments can be formed from a natural fiber length which is normally about 6 to about 50 millimeters, but longer and more continuous filaments can be formed depending on the filament extrusion process being used and therefore filaments which are more continuous in their nature are found in conjunction with melt blow forming and spinning processes are also contemplated to be within the scope of the present invention. Furthermore, filaments with much shorter lengths, shorter than those normally used for natural fiber purposes, can be formed for still other uses.
    [0013] Typically, the thickening agent has a viscosity average molecular weight (Mv) of between about 200,000 and about 2,000,000 which can be determined by standard methods used in the industry depending on the material in question. Although a wide number of thickening agents may be suitable for use in forming the filaments, the thickening agent can be selected from the group consisting of polyethylene oxide, poly(vinyl pyrrolidone), nanocrystalline cellulose, hemicellulose and nanostarch.
    [0014] To form a filament and the resulting non-woven fibrous web according to the present invention, a water-based dispersion of the precursor absorbent material as described above must first be formed and then mixed at a viscosity of about 400 to about 3000 Pascal seconds (Pa s) at a shear rate of 100 seconds reciprocal (s-1). Generally, for filament extrusion, the shear rate during the spinning process will be between 50 and 200 seconds reciprocal. Once within the viscosity and shear rate ranges indicated above, the absorbent precursor material can be extruded using a filament matrix or otherwise formed into a filament-forming surface and then dried. The filaments thus formed can then be subjected to further processing steps such as cutting or chopping into small filament lengths as well as folding to increase their mass.
    [0015] With larger heads of a multi-extruder or other types of extrusion holes and devices, the absorbent precursor material could be extruded into a plurality of filaments which are then deposited in a random pattern onto a surface to form a fibrous web of non-woven fabric which is then dried and, if desired, subjected to further treatment. For example, either before, in conjunction with or after the drying process, the fibrous non-woven web can be subjected to bonding and/or interweaving processes to further improve the strength and integrity of the web as a whole. In one form of the joining process, one or both of the flat embossed calender rolls can be used to alter the surface texture and appearance of the fibrous non-woven web so formed or to print embossed designs to alter the aesthetic properties of the non-woven or to give it a greater three-dimensional character and volume. Due to the affinity of the formed filaments with water, it may be more suitable to use non-water-based braiding processes such as needle or air braiding processes. However, it is possible to add small amounts of water, such as by a water spray, to the formed filaments/non-wovens followed by compaction/embossing with embossing/calender rollers. Generally, the amount of unadded water should be no more than five percent by weight, based on the weight of water and filament/non-woven compared to the weight of filament/non-woven prior to addition of water.
    [0016] Once the filaments have been formed, it is believed that their internal resistance is based, at least in part, on hydrogen bonds within the filaments themselves. It should be recognized, however, that this initial integrity can be enhanced through other treatments such as coating the surface of the filaments or the resulting non-woven fibrous web with additional bonding agents such as glues and polymer coatings.
    [0017] The resulting filaments can be used in a wide variety of applications. They can be used alone or they can be blended with other fibers (both natural and synthetic) to form fibrous non-woven webs with additional properties. In addition, other components can be added to the filaments as part of the precursor absorbent material or after formation of the filaments before or after the filaments are completely dry. For example, a superabsorbent material in fiber or particle form can be added to or with the filaments to form high-capacity structures such as fibrous non-woven webs that can function to absorb bodily fluids such as urine, menstruation and fecal material. . Other components such as dyes, pigments, treatments and activated particulate material can be added to the precursor absorbent material or filaments once formed. Treatments that can be added to the filaments as part of the precursor absorbent material or formed filaments can include, but are not limited to, flame retardants, polymer coatings, and surface tension modifiers to name but a few.
    [0018] Fibrous non-woven webs incorporating cellulosic textile filaments in accordance with the present invention can be used alone or in combination with other materials and layers to form multifunctional structures, laminates and products. They can be positioned adjacent to or laminated with other fibrous non-woven materials, film layers and combinations thereof. In this regard, fibrous non-woven webs which incorporate or formed from cellulosic textile filaments in accordance with the present invention may be joined or wrapped with other materials or substrates such as other fibrous non-woven webs and other materials.
    [0019] Absorbent articles including absorbent personal care articles are a product field where the filaments or fibrous webs of non-woven fabrics containing such filaments can be used as a whole or at least a portion of articles of such absorbent articles. Examples of such absorbent articles include but are not limited to diapers, diaper pants, incontinence devices for adults and children, feminine hygiene products, including sanitary napkins, underwear protectors, and tampon pads, as well as bandages, wipes, pads. bedding, nursing pads, and other paper-based products. The fibrous non-woven filaments and webs containing such filaments can also be used to form all or a portion of other products including, but not limited to, hygiene-related products such as cleaning wipes, makeup and beauty wipes and absorbents as well as cleaning products such as handkerchiefs and towels, paper towels, mop protectors, etc. In addition, non-woven filaments and fibrous webs containing such filaments can also be used to form all or a portion of other products such as wipes and disposable garments for use in a wide variety of applications including industrial, cleanroom and related applications. to health care. BRIEF DESCRIPTION OF THE DRAWINGS
    [0020] Figure 1 is a proposed commercial classification process that could be used to form cellulosic textile filaments and fibrous nonwoven webs in accordance with the present invention.
    [0021] Figure 2 is a proposed alternative commercial grading process that could be used to form cellulosic textile filaments and fibrous nonwoven webs in accordance with the present invention.
    [0022] Figure 3 is a graph showing the complex or dynamic viscosity of a cellulosic filament precursor absorbent material according to the present invention based on sample number 10 in the examples. The graph shows viscosity in Pascal seconds (Pa s) as a function of angular frequency (shear rate) in reciprocal seconds. DETAILED DESCRIPTION OF THE INVENTION Material Components
    [0023] The cellulosic textile filament precursor absorbent material has three main components, a solvent, microfibrillar cellulose and a thickening agent. Other components can be included to vary the properties of the filaments and resulting end products as will be explained in more detail below. Solvent
    [0024] The solvent used to make the cellulosic precursor absorbent material is water at a minimum water-based meaning that essentially water and in any case at least 90 percent by volume of the solvent is composed of water. An important advantage of the present invention is its low-cost approach and the fact that there is no need to use additional components other than microfibrillar cellulose and a thickening agent to form the spin absorbent material, a filament, and the resulting non-woven fibrous webs. and the final products. As a result, no chemical-based solvents are required to dissolve the cellulose and no extraction, washing or other chemical removal processes need to be used to generate microfibrillar and non-woven cellulose filaments as is the case with other well-known processes such as Lyocell process. If desired, the water source can be purified and/or distilled, but this is not necessary for the process and the resulting material to work.
    [0025] As shown by the examples below, the process can be carried out at room temperature but if desired, the water-based solvent and the resulting cellulosic filament precursor absorbent material can be heated to an elevated temperature. Whether heat is added to the process in some cases will depend on the thickening agent being used. Also, the temperature range used will depend on the pressures being used to extrude the filaments. At normal atmospheric pressure, temperatures should be below the boiling point of water so as not to cause bubbles to form that could stop the formation of filaments. As a result, temperatures are generally below about 200 degrees Fahrenheit (93°C). However, as extrusion pressures increase, the temperature of the absorbent precursor material and the water contained therein can be raised to temperatures above 212 degrees Fahrenheit (100°C), but generally, under normal conditions at sea level/STP, the temperatures should remain below about 210 degrees Fahrenheit (99°C) so that water does not quickly pass as vapor and disturb the filament formation.
    [0026] Typically, the water-based solvent will be present in the water-based dispersion precursor absorbent material at a weight percent of about 75 to about 95 weight percent based on the total weight of the precursor absorbent material including dry and wet ingredients. Microfibrillary Cellulose
    [0027] The main dry component of the cellulosic textile filaments of the present invention is microfibrillar or microfibrillated cellulose also known as "MFC". Microfibrillary cellulose is a form of cellulose generated by applying high shear forces to cellulosic fibers to generate cellulose fibers, with a lateral dimension or diameter in the range of about 10 to about 100 nanometers (nm) and lengths that are generally in the micrometer scale.
    [0028] One of the advantages of the present invention is that the cellulosic sources available to form the microfibrillary cellulose for the present invention are almost infinite. Generally, any cellulosic source that can, with proper treatment, generate microfibrillated cellulose fibers of the above mentioned size, can become a source of such MFC for the present invention. Some examples of cellulose sources include, but are not limited to, cellulose pulp, algae, trees, grasses, Kenaf plant, hemp, jute, bamboo and microbial cellulose.
    [0029] Numerous articles and literature are available on microfibrillar cellulose, its sources and production. See, for example, Turbak A, Snyder F, Sandberg K (1983) Microfibrillated cellulose: a new cellulose product: properties, uses, and commercial potential. J Appl Polym Sci Appl Polym Symp 37:815-827 which is incorporated herein by reference in its entirety. See also Chinga-Carrasco, Gary (June 13, 2011), Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of microfibrillar cellulose components from a plant physiology and fiber technology point of view, Nanoscale Res Lett. 2011; 6(1): 417. published online 2011 June 13. doi: 10.1186/1556-276X-6-417PMCID: PMC3211513 which is incorporated herein by reference in its entirety.
    [0030] Microfibrillar cellulose can be manufactured, for example, by mechanical disintegration of cellulose fibers. To do this, first, a cellulose source such as long fiber cellulose pulp is crushed in a Willey mill and passed through a 0.50 mm sieve. Willey mills, such as the Mini model, are available from Thomas Scientific in Swedesboro, New Jersey. After the cellulose has been ground, it is then refined using a PFI mill to 3x10k rotations and then diluted with water to approximately 0.2% solids, based on the total weight of the cellulose source and water, and passed through a bench top homogenizer DeBee available from BEE International Inc. of South Easton, Massachusetts three times at 22,000 pounds per square inch (1.52x108 Pascals). Finally, the homogenized material is centrifuged with a Beckman Avanti J-E centrifuge at 12,000 revolutions per minute (rpm) for thirty minutes to obtain the microfibrillated cellulose. (For more information on PFI mills refer to TAPPI test method - T 248 sp-08 which is incorporated herein by reference in its entirety).
    [0031] Typically, microfibrillar cellulose will be present in the water-based dispersion precursor absorbent material at a weight percent of about 7 to about 20 weight percent based on the total weight of the precursor absorbent material including the dry ingredients and moist. In the finished and dry filament, the microfibrillary cellulose content will range from about 80 to about 99.5% by weight based on the total dry weight of the filament.
    [0032] For the examples and test suite described below, microfibrillar cellulose was obtained from the Georgia Institute of Technology in Atlanta, Georgia. The microfibrillary cellulose obtained once formed was centrifuged with a Beckman Avanti JE centrifuge at 12,000 rpm for 30 minutes to produce a sludge-like microfibrillary cellulose product having a weight of 109.1 grams and an average solids content of 15.2% .
    [0033] Anticipated advantages of filaments formed from microfibrillar cellulose are that the filaments so produced will have similar strength to polypropylene fibers of similar size with less elongation. Furthermore, filaments formed from microfibrillar cellulose can sustain superior drying and higher temperatures compared to polymer-based fibers such as polyolefins including polypropylene. Unlike polyolefin-based nonwovens, those made from microfibrillar cellulose filaments are inherently wettable and have greater absorbent capacity. Thickening Agents
    [0034] To change the dynamic viscosity (also referred to as the complex viscosity) of microfibrillary cellulose dispersed in the water-based solvent, thickening agents can be employed and dissolved in the absorbent material precursor of the water-based dispersion to aid in extrusion and in the filament formation process Suitable thickening agents will need to be able to increase the viscosity of the water-based dispersion of microfibrillary cellulose. Typically, the thickening agent will cause the water-based dispersion of microfibrillary cellulose to have a dynamic viscosity between about 400 and about 3000 Pascal seconds (Pa s) at a shear rate of 100 seconds reciprocal (s-1), more specifically between about 800 and about 1250 Pa s, at a shear rate of 100 s-1.
    [0035] Complex viscosity follows Newton's law and is written as
    . The star is used to indicate that viscosity is measured in an oscillatory test instead of the normal steady state shear rate test, for example, in a capillary rheology measurement. According to the Cox/Merz rule,
    if the values of
    and co(s-1) are the same. Complex viscosity can be used to define processing conditions.
    [0036] Complex viscosity is a function of frequency dependent viscosity determined in response to a forced sinusoidal oscillation of the shear stress. It is obtained by dividing the complex modulus by the angular frequency
    and is used to study the viscoelastic nature of a fluid. When a visco-elastic fluid is sinusoidally stressed, the resulting sinusoidal shear rate function is somewhere between a completely in-phase and out-of-phase response. The component within the phase is the real part of the complex viscosity ( η'=G”/ ω), also known as the dynamic viscosity and represents the viscous behavior and the imaginary part of the complex viscosity.
    represents elastic behavior. The complex viscosity function is expressed as the difference between the in-phase viscosity and the out-of-phase viscosity or the imaginary components of the complex viscosity, η*= η'- η".
    [0037] Dynamic or complex viscosity can be measured using an Anton Paar rheometer model Physica MCR 301 supplied by Anton Paar GmbH of Graz, Austria under ambient temperature conditions (70°F/21°C). The determination of the complex viscosity of an absorbent cellulosic precursor material can be determined in accordance with the manual for this apparatus which is incorporated herein by reference in its entirety. The determination of viscosity versus shear rate for sample 10 of the examples is shown in Table 3 and Figure 3 of the drawings.
    [0038] Specific examples of thickening agents include, but are not limited to, polyethylene oxide (PEO), polyvinylpyrrolidone, nanocrystalline cellulose, hemicellulose, and nanostarch. Examples of PEO include those available from Sigma-Aldrich Co, LLC of Saint Louis, Missouri including grade 372781 PEO with a viscosity average molecular weight (Mv) of 1,000,000, grade 182028 with a viscosity average molecular weight (Mv) ) of 600,000 and grade 181994 with an average viscosity molecular weight (Mv) of 200,000. An example of a suitable polyvinylpyrrolidone is grade 437190 also available from Sigma-Aldrich with a weight average molecular weight (Mw) of 1,300,000. Nanocrystalline cellulose is available from CelluForce, Inc. of Montreal, Canada. Regarding the molecular weight of the thickening agent it should be noted that some molecular weights are reported by manufacturers and suppliers as number average molecular weight (Mn), weight average molecular weight (Mw) and viscosity molecular weight (Mv). Thus, the proper molecular weight version must be determined by standardized methods as used by the industry for the particular material in question.
    [0039] Other examples of thickening agents include, but not limited to, maltodextrin, isolated soy protein, carboxymethylcellulose, alginic acid, gelatin, textured soy protein, guar gum, xanthan gum, modified corn starch, carrageenan, sugar, ester , calcium alginate, pectic substances, konjac, liquid glucose and sodium triphosphate. Furthermore, it should be noted that this list is not exhaustive and other thickening agents are also contemplated to be within the scope of the present invention as long as they are compatible with the other components of the water-based dispersion precursor absorbent material and process parameters and equipment chosen to form the filaments in accordance with the present invention.
    [0040] In general, suitable thickening agents for the present invention will have average viscosity molecular weights (Mv) up to about 2,000,000. Generally, the average viscosity molecular weight of the thickening agent will range between 200,000 and about 2,000,000 and more specifically between about 500,000 and about 1,000,000 although other molecular weights may be used depending on the specific end user application. The amount of thickening agent that will be used typically ranges from about 0.2 to about 3.0 percent by weight based on the total weight of the water-based dispersion precursor absorbent material including the weights of the solvent, the microfibrillary cellulose. , the thickening agent and any other additives or components. The end result of the type and amount of such thickening agents used in the precursor absorbent material is the desire to generate an absorbent precursor material that falls within the viscosity ranges indicated above, so that suitable filaments can be extruded by the specific equipment used.
    [0041] In the finished and dry filament, the content of thickening agent will range between about 20% and about 0.5 percent by weight based on the total dry weight of the filament. Other Components
    [0042] Although a solvent, a thickening agent and a microfibrillar cellulose are the main components of the precursor absorbent material, end-user filaments and non-woven fibrous webs, other components may be included depending on the particular end-user application. Other components include, but are not limited to, water-based agents. Di-aldehydes are an example of binding agents that can be used with the present invention. Typically, the bonding agent being used must be designed not to prematurely cross-link at a point where it interferes with the formation of the absorbent material or the filament formation process. As a result, it is desirable to use bonding agents that can be activated or facilitated in their bonding through the use of additional heat as can be applied during the drying process after the filaments have been formed. An example in this regard is an acrylic latex binder that can be accelerated with heated air to temperatures of about 300°F/149°C.
    [0043] When other components are added to the filament-precursor absorbent material, it is generally desirable to add them in such an amount that the finished, dry filament will, based on the total dry weight of the filament, be from about 75 to about 99 % by weight of microfibrillar cellulose fibers, from about 20 to about 0.5% by weight of a thickening agent, and from 0.5 to about 5% of other components. Equipment and Process
    [0044] The cellulosic textile precursor absorbent material and the filaments defined in the examples below were manufactured using bench scale equipment. The microfibrillary cellulose, thickening agent and water were mixed in the prescribed proportions on a weight percent basis based on the total weight of all dry and wet components in a 150 milliliter container and stirred manually using a glass stir rod to the fullest. high level of uniformity and dispersion possible to form the precursor absorbent material. Typically, this took about 60 to 120 minutes of repeated shaking intervals for 1 or 2 minutes and letting the rest of the sample rest for five to ten minutes until an acceptably uniform dispersion was obtained (visually without nodules). Precursor absorbent material was poured into the open end of an ordinary plastic disposable syringe of 25 milliliter capacity which had no needle. The plunger was replaced and the air removed. The exit hole in the syringe from which the absorbent material was extruded had a diameter of approximately one millimeter. The syringe was held by hand at a 45-degree angle to a horizontal laboratory bench surface on which a silicone-treated paper was positioned which formed the horizontal forming surface on which the absorbent material was deposited. The tip of the syringe was held approximately two centimeters above the forming surface.
    The filaments were extruded from the portable syringe while the syringe was pulled back as the absorbent precursor material was extruded from the syringe tip by pressing the plunger into the syringe housing. Filament lengths were in the range of approximately 300mm. Initial wetted diameters of the filaments were approximately one millimeter. The filaments were allowed to air dry at room temperature overnight. After drying, the filaments exhibited contraction in their diameters. Dry diameters were approximately 0.25 millimeters. All portions of the process described above were carried out at room temperature (75°F/21°C). Visual observation of the filaments that these were well formed and the filaments exhibited good tensile strength when pulled by hand.
    [0046] Due to the low solids content of the water-based dispersion textile filament precursor absorbent material, the shrinkage of the newly formed filament and therefore the decrease in filament diameter should be considered as a factor in the process parameters. For example, if a filament with a diameter of 30 microns is desired once the filament has dried from an absorbent precursor material having a solids content of approximately ten percent, the initial diameter of the filament will have to be approximately 95 microns. to compensate for the contraction. This relationship is linear and therefore, for example, at the same ten percent solids content, a dry filament of 10 microns will require an approximate wet filament diameter of 32 microns. In addition, the downward drawing of the filament as it is extruded must also be taken into account. It should normally be assumed that drawing down the filament diameter in a commercial process will be in the 50 to 80 percent range. Thus, if a dry filament diameter of 5 to 50 microns is desired using an absorbent precursor material of approximately 15 percent solids, it is anticipated that the wet filament diameter will have to be in the range of 70 to 100 microns. As a result, it is also anticipated that extrusion equipment will have to use extrusion openings or holes with diameters in the range of 70 to 100 microns to produce finished and dry filaments with filament diameters in the range of 5 to 50 microns although this may be suitably adjusted depending on the viscosity of the water-based dispersion precursor absorbent material, the amount of drawing of the filaments as they are extruded, the height of formation of the extrusion holes, the forming surface, the flow rate of the precursor absorbent material of the holes , the drawing of the filaments and the speed of the forming surface.
    [0047] As described in the examples, microfibrillar cellulose filaments were manufactured using bench scale equipment, but it is anticipated that conventional fiber extrusion equipment can be used including, for example, equipment used in the manufacture of cellulosic and non-woven fibers according to the Lycocell process. See, for example, US Patent Nos. 6,306,334 and 6,235,392 both to Luo et al.; US Patent Application No. 2011/0124258 to White et al. and WO 01/81664 to Luo et al., each of which is incorporated herein by reference in its entirety. This type of equipment can be used to mix and rotate the microfibrillary cellulose filaments according to the present invention with the difference being that: 1) no chemicals need be added to the solvent used to dissolve the cellulose, 2) minimal gas requirement or mechanical stretching needs to be used due to the tenacity of the filaments being formed, 3) no insolubilization step needs to be used and lastly, 4) no washing or chemical extraction step needs to be implemented to generate the resulting filaments. Figure 1 illustrates a schematic diagram of a process that could be used to form the fibrous filaments and webs of non-woven fabrics in accordance with the present invention.
    [0048] Returning to Figure 1, a process and equipment 10 according to the present invention is shown which includes a tank of precursor absorbent material 12, a rotation pump 14 and an extrusion die 16. The absorbent precursor material is placed in the tank of absorbent material 12 and pumped into the extrusion die 16 via the spin pump 14. The precursor absorbent material exits the extrusion die 16 in the form of filaments 20 which are deposited onto a forming surface 24. If desired, a unit Optional drawing die 22 can be used between extrusion die 16 and forming surface 24 to further draw and smooth the filaments as they exit extrusion die 16 and before they are deposited onto forming surface 24. vacuum 26 can be used to facilitate deposition of the filaments onto the forming surface 24 to form a fibrous web of non-woven fabric 28. After the web 28 is formed, it can be formed. subjected to a drying step through a dryer 30 and, if desired, other processing steps as mentioned above including, but not limited to, such steps as calendering and/or embossing, when passing the non-weft. fabric 28 through the grip area 32 of a pair of calender/embossing rollers 34 and 36, or both before and after dryer 30.
    [0049] A possible alternative application of a process for forming cellulosic filaments according to the present invention is shown in Figure 2 of the drawings. In the present application, in which similar numerals represent similar components, a two-stage drying process can be employed in which the newly formed fibrous non-woven web 28 is subjected to a first drying step through dryer 30a after which the The web 28 is subjected to a spray of water 38 followed by a second drying step through the dryer 30b. Typically, the addition of water is no more than about five percent by weight based on the weight of the non-woven fibrous web and the water. EXAMPLES
    [0050] The MFC concentrate before being released is a very viscous paste. As a result, water must be added in increasing amounts to the MFC to generate a precursor of adequate viscosity. When this is done, specified amounts of PEO thickening agent can be added. If necessary, additional water can be added during the manual mixing process to generate a precursor absorbent material of suitable viscosity after which the absorbent material can be manually extruded with the syringe described above. Satisfactory absorbent materials were made from 5.0-7.5 wt% microfibrillar cellulose and 1.0-2.3 wt% PEO based on the total weight of all wet and dry ingredients in the absorbent material. Filaments were produced by extruding the absorbent material at room temperature from a simple syringe and leaving them in dry air. Filaments thus produced were quite resistant.
    [0051] A total of ten samples of the microfibrillary cellulose precursor absorbent material were fabricated and formed into filaments. Data on these ten samples are set out in Table 1 below. Three components were used to form the microfibrillar cellulose precursor absorbent material including microfibrillar cellulose, a thickening agent and tap water as a solvent. Microfibrillar cellulose was obtained from the Georgia Institute of Technology in Atlanta, Georgia. The microfibrillary cellulose sample material had an oven dried weight of 16.6 grams. The homogenized microfibrillary cellulose (~0.16%) was centrifuged with a Beckman Avanti J-E centrifuge at 12000 rpm for 30 minutes, after which a slurry-like microfibrillary cellulose product was obtained. The solids content within the centrifuged microfibrillary cellulose sample was not uniform, as there was a graduation of the solids content from 12.52% at the top of the sample to 19.35% at the bottom of the sample with the average solids content of 15, two%. The sample weighed 109.1 g, and then multiplying the weight in grams by the solids content (109.1 g x 0.152) yielded an oven-dried weight of 16.6 g for the microfibrillary cellulose.
    The thickening agents used in the samples were the three previously identified polyethylene oxides (PEO) available from Sigma-Aldrich Co., LLC of Saint Louis, Missouri. The thickening agent referred to as "Low" in Table 1 below was class 181994 with a viscosity average molecular weight (Mv) of 200,000. The thickening agent identified as "Medium" in Table 1 below was class 182028 with a viscosity average molecular weight (Mv) of 600,000 and the thickening agent identified as "High" was class 372781 PEO with a viscosity average molecular weight ( Mv) of 1,000,000.
    [0053] Samples 1, 2 and 3 did not contain MFC. The purpose of these samples was to determine the effect of the quantity and type (molecular weight) of the thickening agent on the viscosity of the water solvent. The intention was to create a precursor with a viscosity similar to molasses. In example 4, only MFC was added to the water, again to determine a subjective viscosity. In samples 5 and 6, varying amounts of MFC and medium molecular weight PEO were added to the water. The intention here was to focus on determining a mix ratio between the MFC and the average molecular weight PEO class.
    [0054] In samples 7 and 8, varying amounts of MFC were added to the water, but no thickening agent was used to observe the level of dispersion of MFC in the solvent. In samples 9, MFC and average molecular weight PEO were added to the water in an effort to optimize component proportions and to determine the order of mixing. It was found that the preferred method was to add the MFC to the water first and then add this to the thickening agent.
    [0055] Finally, in sample 10, the MFC and the high molecular weight PEO were added to the water in an effort to optimize the mixture using the higher molecular weight PEO as, from a commercial point of view, it is more convenient to use a higher molecular weight thickening agent so as to minimize the concentration of thickening agent needed to form a suitable precursor absorbent material.
    [0056] Samples 9 and 10 were both formed into filaments in the manner described above using a hand syringe. In addition, the dynamic or complex viscosity of sample 10 precursor was measured along with the storage and loss modulus. Data are presented in Tables 2 and 3, and a graph of the data is shown in Figure 3 of the drawings. Sample 10 was used for this calculation as it appeared to have a viscosity that approached the desired ideal for a viscosity in the shear rate range for filament production. Table 1
    [0057] Weight percentages are given based on the total weight of the microfibrillar cellulose, thickening agent and water.
    Table 2
    [0058] Input data for dynamic viscosity, storage module data and loss module in Table 3 below and Figure 3 of the drawings. Data Series Information
    Table 3
    [0059] Data points for complex viscosity (dynamic), storage modulus and loss modulus shown in Figure 3 of the drawings.


    [0060] These and other modifications and variations to the present invention may be made by persons of ordinary skill in the art, without departing from the spirit and scope of the present invention, which are more particularly presented in the appended claims. Furthermore, it should be understood that aspects of the various applications can be interchanged, in whole or in part. Furthermore, persons of ordinary skill in the art will note that the above description is for the purpose and example only and is not intended to limit the invention so further described in the appended claims.
    权利要求:
    Claims (11)
    [0001]
    1. Cellulosic filament precursor absorbent material characterized in that it comprises, based on the total weight of said precursor absorbent material, from 7 to 20 percent by weight of microfibrillary cellulose fibers, 0.2 to 3 percent by weight of a thickening agent and 75 to 95 percent by weight of a water-based solvent, said microfibrillar cellulose fibers being dispersed in said solvent and said thickening agent being dissolved in said solvent, said precursor absorbent material having a varying dynamic viscosity 800 to 3000 Pascal seconds at a shear rate of 100 seconds reciprocal.
    [0002]
    2. Cellulosic filament precursor absorbent material according to claim 1, characterized in that it has a dynamic viscosity ranging from 800 to 1250 Pascals according to a shear rate of 100 seconds reciprocal.
    [0003]
    3. Cellulosic filament precursor absorbent material according to claim 1, characterized in that said thickening agent has a molecular weight of average viscosity between 200,000 and 2,000,000. [001]
    [0004]
    4. Cellulosic filament precursor absorbent material according to claim 1, characterized in that said thickening agent is selected from the group consisting of polyethylene oxide, poly(vinyl pyrrolidone), nanocrystalline cellulose, hemicellulose and nano-starch.
    [0005]
    5. Process for forming a cellulosic filament, characterized in that it comprises mixing a cellulosic textile precursor absorbent material, as defined in claim 1, for a viscosity of 800 to 3000 Pa s at a shear rate of 100 seconds reciprocal, extruding said material precursor absorbent into a filament and drying said filament.
    [0006]
    6. Process according to claim 5, characterized in that the cellulosic filament comprises, based on the total dry weight of said filament, from 80 to 99.5 percent by weight of microfibrillary cellulose fibers and 20 to 0. 5 percent by weight of a thickening agent.
    [0007]
    7. Process according to claim 5, characterized in that the cellulosic filament has a diameter between 5 and 50 microns.
    [0008]
    8. Process according to claim 5, characterized in that said extrusion and drying comprises extruding said absorbent precursor material into a plurality of filaments, depositing said filaments in a random pattern on a surface to form a non-woven web and drying said non-woven weft.
    [0009]
    9. Process according to claim 9, characterized in that it further includes subjecting said non-woven weft to a union or interweaving process.
    [0010]
    10. Absorbent article, characterized in that at least a portion of said article comprises the cellulosic filament formed by the process as defined in claim 5.
    [0011]
    11. Absorbent article according to claim 10, characterized in that said article is selected from the group consisting of a diaper, a diaper pants, a training pants, an incontinence device, a feminine hygiene product, a bandage or a handkerchief.
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    同族专利:
    公开号 | 公开日
    KR101799658B1|2017-11-20|
    RU2615109C2|2017-04-03|
    BR112015009359A2|2017-07-04|
    RU2015118531A|2016-12-10|
    AU2013340447B2|2017-12-07|
    EP2917389A1|2015-09-16|
    MX2015005020A|2015-07-17|
    MX360516B|2018-11-05|
    AU2013340447A1|2015-05-21|
    EP2917389A4|2016-06-01|
    EP2917389B1|2018-12-05|
    CN104736749A|2015-06-24|
    US9422641B2|2016-08-23|
    CN104736749B|2017-10-31|
    US20140121622A1|2014-05-01|
    WO2014068441A1|2014-05-08|
    KR20150080514A|2015-07-09|
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    法律状态:
    2018-03-06| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2018-03-13| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2018-03-20| B06I| Publication of requirement cancelled [chapter 6.9 patent gazette]|Free format text: ANULADA A PUBLICACAO CODIGO 6.6.1 NA RPI NO 2462 DE 13/03/2018 POR TER SIDO INDEVIDA. |
    2021-05-25| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-07-06| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 22/10/2013, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    US201261720510P| true| 2012-10-31|2012-10-31|
    US61/720,510|2012-10-31|
    US14/044,571|2013-10-02|
    US14/044,571|US9422641B2|2012-10-31|2013-10-02|Filaments comprising microfibrillar cellulose, fibrous nonwoven webs and process for making the same|
    PCT/IB2013/059550|WO2014068441A1|2012-10-31|2013-10-22|Filaments comprising microfibrillar cellulose, fibrous nonwoven webs and process for making the same|
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