Patent Application
20220380983
This disclosure relates to paper towel products with high softness and absorbency, and in particular relates to paper towel products made using structuring fabrics or belts that include polymeric layers.
Across the globe there is great demand for disposable, absorbent structures used for household cleaning tasks. Disposable towels and wipes meet this market demand. Disposable paper towels and wipes that are composed of cellulosic based fibers are also nearly 100% renewable and biodegradable, thus catering to those whom are eco-conscious. These disposable absorbent towels and wipes are used for a multitude of tasks that require absorbency and strength. These tasks include absorbing liquid spills, cleaning windows and mirrors, scrubbing countertops and floors, scrubbing and drying dishes, washing/cleaning bathroom sinks and toilets, and even drying/cleaning hands and faces where the attribute of softness becomes particularly important. A disposable towel or wipe that can perform these demanding tasks and be produced at a price point that provides a value proposition to the consumer is advantageous. To maintain a low price point, as well as conserve cellulosic based natural resources, providing for high strength and absorbency using the least amount of material is advantageous.
The industrial methods or technologies used to produce these absorbent structures are numerous. Absorbent structures can be produced using both Water or Air-Laid technologies. The technologies that use water to form the cellulosic (or other natural or synthetic fiber type) webs of which towels or wipes are comprised are called Water-Laid Technologies. These include Through Air Drying (TAD), Uncreped Through Air Drying (UCTAD), Conventional Wet Crepe (CWC), Conventional Dry Crepe (CDC), ATMOS, NTT, ETAD, and QRT. Technologies that use air to form the webs of which towels or wipes are comprised are called Air-Laid Technologies. To enhance the strength and absorbency of these towels and wipes, more than one layer of web (or ply) can be laminated together using strictly a mechanical process or preferably a mechanical process that utilizes an adhesive.
Conventional Water Laid manufacturing processes (CWC, CDC) include a forming section designed to retain a fiber, chemical, and filler recipe while allowing water to drain from a web. Many types of forming sections, such as inclined suction breast roll, gap former twin wire C-wrap, gap former twin wire S-wrap, suction forming roll, and Crescent formers, include the use of forming fabrics.
Forming fabrics are woven structures that utilize monofilaments (such as yarns or threads) composed of synthetic polymers (usually polyethylene terephthalate, or nylon). A forming fabric has two surfaces, a sheet side and a machine or wear side. The wear side is in contact with the elements that support and move the fabric and are thus prone to wear. To increase wear resistance and improve drainage, the wear side of the fabric has larger diameter monofilaments compared to the sheet side. The sheet side has finer yarns to promote fiber and filler retention on the fabric surface.
Different weave patterns are utilized to control other properties such as: fabric stability, life potential, drainage, fiber support, and clean-ability. There are three basic types of forming fabrics: single layer, double layer, and triple layer. A single layer fabric is composed of one yarn system made up of cross direction (CD) yarns (also known as shute yarns or weft yarns) and machine direction (MD) yarns (also known as warp yarns). The main issue for single layer fabrics is a lack of dimensional stability. A double layer forming fabric has one layer of warp yarns and two layers of shute yarns or weft yarns. This multilayer fabric is generally more stable and resistant to stretching. Triple layer fabrics have two separate single layer fabrics bound together by separated yarns called binders. Usually the binder yarns are placed in the cross direction but can also be oriented in the machine direction. Triple layer fabrics have further increased dimensional stability, wear potential, drainage, and fiber support as compared to single or double layer fabrics.
The manufacturing of forming fabrics includes the following operations: weaving, initial heat setting, seaming, final heat setting, and finishing. The fabric is made in a loom using two interlacing sets of monofilaments (or threads or yarns). The longitudinal or machine direction threads are called warp threads and the transverse or cross machine direction threads are called shute threads. After weaving, the forming fabric is heated to relieve internal stresses to enhance dimensional stability of the fabric. The next step in manufacturing is seaming. This step converts the flat woven fabric into an endless forming fabric by joining the two MD ends of the fabric. After seaming, a final heat setting is applied to stabilize and relieve the stresses in the seam area. The final step in the manufacturing process is finishing, whereby the fabric is cut to width and sealed.
There are several parameters and tools used to characterize the properties of the forming fabric: mesh (warp count) and knock (weft count), caliper, frames, plane difference, percent open area, air permeability, tensile strength and modulus, stiffness, shear resistance, void volume and distribution, running attitude, fiber support index, drainage index, and stacking. None of these parameters can be used individually to precisely predict the performance of a forming fabric on a paper machine, but together the expected performance and sheet properties can be estimated. Examples of forming fabric designs can be viewed in U.S. Pat. Nos. 3,143,150, 4,184,519, 4,909,284, and 5,806,569.
In a CDC or CWC process, after web formation and drainage (to around 35% solids) in the forming section (assisted by centripetal force around the forming roll and, in some cases, vacuum boxes), a web is transferred from the forming fabric to a press fabric upon which the web is pressed between a rubber or polyurethane covered suction pressure roll and a steam heated cylinder referred to as the Yankee dryer. The press fabric is a permeable fabric designed to uptake water from the web as it is pressed in the press section. It is composed of large monofilaments or multi-filamentous yarns, needled with fine synthetic batt fibers to form a smooth surface for even web pressing against the Yankee dryer. Removing water via pressing reduces energy consumption compared to using heat. The web is transferred to the Yankee Dryer, and then dried (with assistance of a hot air impingement hood) and creped from the Yankee Dryer and reeled. When creped at a solids content of less than 90%, the process is referred to as Conventional Wet Crepe. When creped at a solids content of greater than 90%, the process is referred to as Conventional Dry Crepe. These processes can be further understood by reviewing Yankee Dryer and Drying, A TAPPI PRESS Anthology, pg 215-219, the contents of which are incorporated herein by reference in their entirety.
In a TAD process, rather than pressing and compacting the web, as is performed in CDC and CWC process, the web undergoes the steps of imprinting and thermal pre-drying. Imprinting is a step in the process where the web is transferred from a forming fabric to a structuring fabric (or imprinting fabric) and subsequently pulled into the structuring fabric using vacuum (referred to as imprinting or molding). This step imprints the weave pattern (or knuckle pattern) of the structuring fabric into the web. This imprinting step increases softness of the web, and affects smoothness and the bulk structure. The monofilaments of the fabric are typically round in shape but can also be square or rectangular. The web contacting side of the fabric is sometimes sanded to provide higher contact area when pressing against the Yankee dryer to facilitate web transfer. The manufacturing method of an imprinting fabric is similar to a forming fabric (see U.S. Pat. Nos. 3,473,576, 3,573,164, 3,905,863, 3,974,025, and 4,191,609, for examples) except in some cases an additional step of overlaying a polymer is performed.
Imprinting fabrics with an overlaid polymer are disclosed in U.S. Pat. Nos. 6,120,642, 5,679,222, 4,514,345, 5,334,289, 4,528,239 and 4,637,859. Specifically, these patents disclose a method of forming a fabric in which a patterned resin is applied over a woven substrate. The patterned resin completely penetrates the woven substrate. The top surface of the patterned resin is flat and openings in the resin have sides that follow a linear path as the sides approach and then penetrate the woven structure.
U.S. Pat. Nos. 6,610,173, 6,660,362, 6,878,238 and 6,998,017, and European Patent No. EP 1 339 915 disclose another technique for applying an overlaid resin to a woven imprinting fabric. According to this technique, the overlaid polymer has an asymmetrical cross sectional profile in at least one of the machine direction and a cross direction and at least one nonlinear side relative to the vertical axis. The top portion of the overlaid resin can be a variety of shapes and not simply a flat structure. The sides of the overlaid resin, as the resin approaches and then penetrates the woven structure, can also take different forms, not a simple linear path 90 degrees relative to the vertical axis of the fabric. Both methods result in a patterned resin applied over a woven substrate. The benefit is that resulting patterns are not limited by a woven structure and can be created in any desired shape to enable a higher level of control of the web structure and topography that dictate web quality properties.
After imprinting, the web is thermally pre-dried by moving hot air through the web while it is conveyed on the structuring fabric. Thermal pre-drying can be used to dry the web to over 90% solids before the web is transferred to a steam heated cylinder. The web is then transferred from the structuring fabric to the steam heated cylinder through a very low intensity nip (up to 10 times less than a conventional press nip) between a solid pressure roll and the steam heated cylinder. The portions of the web that are pressed between the pressure roll and steam cylinder rest on knuckles of the structuring fabric; thereby protecting most of the web from the light compaction that occurs in this nip. The steam cylinder and an optional air cap system, for impinging hot air, then dry the sheet to up to 99% solids during the drying stage before creping occurs. The creping step of the process again only affects the knuckle sections of the web that are in contact with the steam cylinder surface. Due to only the knuckles of the web being creped, along with the dominant surface topography being generated by the structuring fabric, and the higher thickness of the TAD web, the creping process has a much smaller effect on overall softness as compared to conventional dry crepe. After creping, the web is optionally calendared and reeled into a parent roll and ready for a converting process. Some TAD machines utilize fabrics (similar to dryer fabrics) to support the sheet from the crepe blade to the reel drum to aid in sheet stability and productivity. Patents which describe creped through air dried products include U.S. Pat. Nos. 3,994,771, 4,102,737, 4,529,480, and 5,510,002.
The TAD process generally has higher capital costs as compared to a conventional (dry or wet crepe) process due to the amount of air handling equipment needed for the TAD section. Also, the TAD process has a higher energy consumption rate due to the need to burn natural gas or other fuels for thermal pre-drying. However, the bulk softness and absorbency of a paper product made from the TAD process is superior to conventional paper due to the superior caliper generation via structuring fabrics, which creates a low density, high void volume web that retains its caliper when wetted. The productivity of a TAD machine is less than that of a CDC or CWC machine due to the complexity of the process and the difficulty of providing a robust and stable coating package on the Yankee dryer needed for transfer and creping of a delicate pre-dried web.
UCTAD (un-creped through air drying) is a variation of the TAD process in which the web is not creped, but rather dried up to 99% solids using thermal drying, blown off the structuring fabric (using air), and then optionally calendared and reeled. U.S. Pat. No. 5,607,551 describes an uncreped through air dried product.
A process/method and paper machine system for producing paper towel has been developed by the Voith company and is marketed under the name ATMOS. The process/method and paper machine system have several variations, but all involve the use of a structuring fabric in conjunction with a belt press. The major steps of the ATMOS process and its variations are stock preparation, forming, imprinting, pressing (using a belt press), creping, calendaring (optional), and reeling the web.
The stock preparation step of the ATMOS process is the same as that of a conventional or TAD machine. The forming process can utilize a twin wire former (as described in U.S. Pat. No. 7,744,726), a Crescent Former with a suction Forming Roll (as described in U.S. Pat. No. 6,821,391), or a Crescent Former (as described in U.S. Pat. No. 7,387,706). The former is provided with a slurry from the headbox to a nip formed by a structuring fabric (inner position/in contact with the forming roll) and forming fabric (outer position). The fibers from the slurry are predominately collected in the valleys (or pockets, pillows) of the structuring fabric and the web is dewatered through the forming fabric. This method for forming the web results in a bulk structure and surface topography as described in U.S. Pat. No. 7,387,706 (FIGS. 1-11). After the forming roll, the structuring and forming fabrics separate, with the web remaining in contact with the structuring fabric.
The web is then transported on the structuring fabric to a belt press. The belt press can have multiple configurations. The press dewaters the web while protecting the areas of the sheet within the structuring fabric valleys from compaction. Moisture is pressed out of the web, through the dewatering fabric, and into the vacuum roll. The press belt is permeable and allows for air to pass through the belt, web, and dewatering fabric, and into the vacuum roll, thereby enhancing the moisture removal. Since both the belt and dewatering fabric are permeable, a hot air hood can be placed inside of the belt press to further enhance moisture removal. Alternately, the belt press can have a pressing device which includes several press shoes, with individual actuators to control cross direction moisture profile, or a press roll. A common arrangement of the belt press has the web pressed against a permeable dewatering fabric across a vacuum roll by a permeable extended nip belt press. Inside the belt press is a hot air hood that includes a steam shower to enhance moisture removal. The hot air hood apparatus over the belt press can be made more energy efficient by reusing a portion of heated exhaust air from the Yankee air cap or recirculating a portion of the exhaust air from the hot air apparatus itself.
After the belt press, a second press is used to nip the web between the structuring fabric and dewatering felt by one hard and one soft roll. The press roll under the dewatering fabric can be supplied with vacuum to further assist water removal. This belt press arrangement is described in U.S. Pat. Nos. 8,382,956 and 8,580,083, with
The web is now transferred to a steam heated cylinder via a press element. The press element can be a through drilled (bored) pressure roll, a through drilled (bored) and blind drilled (blind bored) pressure roll, or a shoe press. After the web leaves this press element and before it contacts the steam heated cylinder, the % solids are in the range of 40-50%. The steam heated cylinder is coated with chemistry to aid in sticking the sheet to the cylinder at the press element nip and also to aid in removal of the sheet at the doctor blade. The sheet is dried to up to 99% solids by the steam heated cylinder and an installed hot air impingement hood over the cylinder. This drying process, the coating of the cylinder with chemistry, and the removal of the web with doctoring is explained in U.S. Pat. Nos. 7,582,187 and 7,905,989. The doctoring of the sheet off the Yankee, i.e., creping, is similar to that of TAD with only the knuckle sections of the web being creped. Thus, the dominant surface topography is generated by the structuring fabric, with the creping process having a much smaller effect on overall softness as compared to conventional dry crepe. The web is now calendared (optional), slit, reeled and ready for the converting process.
The ATMOS process has capital costs between that of a CDC and a TAD machine. It uses more fabrics and a more complex drying system compared to a conventional machine, but uses less equipment than a TAD machine. The energy costs are also between that of a conventional and a TAD machine due to the energy efficient hot air hood and belt press. The productivity of the ATMOS machine has been limited due to the inability of the novel belt press and hood to fully dewater the web and poor web transfer to the Yankee dryer, likely driven by poor supported coating packages, the inability of the process to utilize structuring fabric release chemistry, and the inability to utilize overlaid fabrics to increase web contact area to the dryer. Poor adhesion of the web to the Yankee dryer has resulted in poor creping and stretch development which contributes to sheet handling issues in the reel section. The result is that the output of an ATMOS machine is currently below that of conventional and TAD machines. The bulk softness and absorbency is superior to conventional, but lower than a TAD web since some compaction of the sheet occurs within the belt press, especially areas of the web not protected within the pockets of the fabric. Also, caliper is limited since there is no speed differential to help drive the web into the structuring fabric as exists on a TAD machine. The surface smoothness of an ATMOS web is between that of a TAD web and a conventional web primarily due to the current limitation on use of overlaid structuring fabrics.
The ATMOS manufacturing technique is often described as a hybrid technology because it utilizes a structuring fabric like the TAD process, but also utilizes energy efficient means to dewater the sheet like the conventional dry crepe process. Other manufacturing techniques which employ the use of a structuring fabric along with an energy efficient dewatering process are the ETAD process and NTT process. The ETAD process and products are described in U.S. Pat. Nos. 7,339,378, 7,442,278, and 7,494,563. The NTT process and products are described in WO 2009/061079 A1, United States Patent Application Publication No. 2011/0180223 A1, and United States Patent Application Publication No. 2010/0065234 A1. The QRT process is described in United States Patent Application Publication No. 2008/0156450 A1 and U.S. Pat. No. 7,811,418. A structuring belt manufacturing process used for the NTT, QRT, and ETAD imprinting process is described in U.S. Pat. No. 8,980,062 and United States Patent Application Publication No. US 2010/0236034.
The NTT fabric forming process involves spirally winding strips of polymeric material, such as industrial strapping or ribbon material, and adjoining the sides of the strips of material using ultrasonic, infrared, or laser welding techniques to produce an endless belt. Optionally, a filler or gap material can be placed between the strips of material and melted using the aforementioned welding techniques to join the strips of materials. The strips of polymeric material are produced by an extrusion process from any polymeric resin such as polyester, polyamide, polyurethane, polypropylene, or polyether ether ketone resins. The strip material can also be reinforced by incorporating monofilaments of polymeric material into the strips during the extrusion process or by laminating a layer of woven polymer monofilaments to the non-sheet contacting surface of a finished endless belt composed of welded strip material. The endless belt can have a textured surface produced using processes such as sanding, graving, embossing, or etching. The belt can be impermeable to air and water, or made permeable by processes such as punching, drilling, or laser drilling. Examples of structuring belts used in the NTT process can be viewed in International Publication Number WO 2009/067079 A1 and United States Patent Application Publication No. 2010/0065234 A1.
As shown in the aforementioned discussion of towel papermaking technologies, the fabrics or belts utilized are critical in the development of the towel web structure and topography which, in turn, are instrumental in determining the quality characteristics of the web such as softness (bulk softness and surfaces smoothness) and absorbency. The manufacturing process for making these fabrics has been limited to weaving a fabric (primarily forming fabrics and structuring fabrics) or a base structure and needling synthetic fibers (press fabrics) or overlaying a polymeric resin (overlaid structuring fabrics) to the fabric/base structure, or welding strips of polymeric material together to form an endless belt.
Conventional overlaid structures require application of an uncured polymer resin over a woven substrate where the resin completely penetrates through the thickness of the woven structure. Certain areas of the resin are cured and other areas are uncured and washed away from the woven structure. This results in a fabric where airflow through the fabric is only possible in the Z-direction. Thus, in order for the web to dry efficiently, only highly permeable fabrics can be utilized, meaning the amount of overlaid resin applied needs to be limited. If a fabric of low permeability is produced in this manner, then drying efficiency is significantly reduced, resulting in poor energy efficiency and/or low production rates as the web must be transported slowly across the TAD drums or ATMOS drum for sufficient drying. Similarly, a welded polymer structuring layer is extremely planar and provides an even surface when laminating to a woven support layer, which results in no air channels in the X-Y plane.
As described in U.S. Pat. No. 10,208,426 B2, fabrics comprised of extruded polymer netting laminated to a woven structure utilize less energy to dry the sheet compared to prior designs. Both the extruded polymer netting layer and woven layer have non-planar, irregularly shaped surfaces that when laminated together only weld together where the two layers come into direct contact. This creates air channels in the X-Y plane of the fabric through which air can travel when the sheet is being dried with hot air in the TAD, UCTAD, or ATMOS processes. Without being bound by theory, it is likely that the airflow path and dwell time is longer through this type of fabric, allowing the air to remove higher amounts of water compared to prior designs. Prior woven and overlaid designs create channels where airflow is channeled in the Z-direction by the physical restrictions imposed by the monofilaments or polymers of the belt that create the pocket boundaries of the belt. The polymer netting/woven structure design allows for less restricted airflow in the X-Y plane such that airflow can move parallel through the belt and web across multiple pocket boundaries and thereby increase contact time of the airflow within the web to remove additional water. This allows for the use of lower permeable belts compared to prior fabrics without increasing the energy demand per ton of paper dried. The air flow in the X-Y plane also reduces high velocity air flow in the Z-direction as the sheet and fabric pass across the molding box, reducing the occurrence of pin holes in the sheet.
Additionally, a process for manufacturing a structuring fabric or the web contacting layer of a laminated structuring fabric by laying down polymers of specific material properties in an additive manner under computer control (3-D printing) has been described in U.S. Pat. No. 10,099,425 and U.S. Provisional Patent Application No. 62/897,596.
Absorbent structures are also made using the Air-Laid process. This process spreads the cellulosic, or other natural or synthetic fibers, in an air stream that is directed onto a moving belt. These fibers collect together to form a web that can be thermally bonded or spray bonded with resin and cured. Compared to Wet-Laid, the web is thicker, softer, more absorbent and also stronger. It is known for having a textile-like surface and drape. Spun-Laid is a variation of the Air-Laid process, which produces the web in one continuous process where plastic fibers (polyester or polypropylene) are spun (melted, extruded, and blown) and then directly spread into a web in one continuous process. This technique has gained popularity as it can generate faster belt speeds and reduce costs.
To further enhance the strength of the absorbent structure, more than one layer of web (or ply) can be laminated together using strictly a mechanical process or preferably a mechanical process that utilizes an adhesive. It is generally understood that a multi-ply structure can have an absorbent capacity greater than the sum of the absorbent capacities of the individual single plies. Without being bound by theory, it is thought this difference is due to the inter-ply storage space created by the addition of an extra ply. When producing multi-ply absorbent structures, it is important that the plies are bonded together in a manner that will hold up when subjected to the forces encountered when the structure is used by the consumer. Scrubbing tasks such as cleaning countertops, dishes, and windows all impart forces upon the structure which can cause the structure to rupture and tear. When the bonding between plies fails, the plies move against each other, thereby imparting frictional forces at the ply interface. This frictional force at the ply interface can induce failure (rupture or tearing) of the structure, thus reducing the overall effectiveness of the product to perform scrubbing and cleaning tasks.
There are many methods used to join or laminate multiple plies of an absorbent structure to produce a multi-ply absorbent structure. One method commonly used is embossing. Embossing is typically performed by one of three processes: tip to tip (or knob to knob), nested, or rubber to steel DEKO embossing. Tip to tip embossing is illustrated by commonly assigned U.S. Pat. No. 3,414,459, while nested embossing process is illustrated in U.S. Pat. No. 3,556,907. Rubber to steel DEKO embossing comprises a steel roll with embossing tips opposed to a pressure roll, sometimes referred to as a backside impression roll, having an elastomeric roll cover wherein the two rolls are axially parallel and juxtaposed to form a nip where the embossing tips of the emboss roll mesh with the elastomeric roll cover of the opposing roll through which one sheet passes and a second unembossed sheet is laminated to the embossed sheet using a marrying roll nipped to the steel embossing roll. In an exemplary rubber to steel embossing process, an adhesive applicator roll may be aligned in an axially parallel arrangement with the patterned embossing roll, such that the adhesive applicator roll is upstream of the nip formed between the emboss and pressure roll. The adhesive applicator roll transfers adhesive to the embossed web on the embossing roll at the crests of the embossing knobs. The crests of the embossing knobs typically do not touch the perimeter of the opposing idler roll at the nip formed therebetween, necessitating the addition of a marrying roll to apply pressure for lamination.
Other attempts to laminate absorbent structure webs include bonding the plies at junction lines wherein the lines include individual pressure spot bonds. The spot bonds are formed using a thermoplastic low viscosity liquid such as melted wax, paraffin, or hot melt adhesive, as described in U.S. Pat. No. 4,770,920. Another method laminates webs of absorbent structure by thermally bonding the webs together using polypropylene melt blown fibers as described in U.S. Pat. No. 4,885,202. Other methods use meltblown adhesive applied to one face of an absorbent structure web in a spiral pattern, stripe pattern, or random pattern before pressing the web against the face of a second absorbent structure as described in U.S. Pat. Nos. 3,911,173, 4,098,632, 4,949,688, 4,891,249, 4,996,091 and 5,143,776.
As described above, there is a need for improved paper towel products with a smooth surface and high caliper. Paper towel products that utilize less cellulose based natural materials may be good for the environment. Paper towels that absorb fluid faster and/or absorb more fluid than current products are desirable to consumers.
The contents of all patents and patent applications mentioned herein are hereby incorporated by reference in their entirety.
An object of the present invention is to provide a two ply rolled Through Air Dried (TAD) paper towel with previously unattained total absorption and absorption rate at a low basis weight. In exemplary embodiments, the paper towel has a unique combination of properties including an Sdr value of greater than about 30 to less than about 65, and a Vvd value of greater than about 4 and less than about 16.
A paper towel product according to an exemplary embodiment of the present invention comprises a laminate of at least two plies, the paper towel product being through air dried, rolled, and disposable, wherein a GATS total absorption of the product is between 17.0 grams water/grams of towel and 21.3 grams water/grams of towel.
A paper towel product according to an exemplary embodiment of the present invention comprises a laminate of at least two plies, the paper towel product being through air dried, rolled, and disposable, wherein a GATS absorption rate of the product is between 5.0 and 6.6 (l/sec0.5).
A paper towel product according to an exemplary embodiment of the present invention comprises a laminate of at least two plies, the paper towel product being through air dried, rolled, and disposable, wherein CD stretch of the product is between 15.5% and 19.2%.
A paper towel product according to an exemplary embodiment of the present invention comprises a laminate of at least two plies, the paper towel product being through air dried, rolled, and disposable, wherein the product has a measured Sdr value between 36 and 60 and a Vvd value between 5 and 14.
In an exemplary embodiment, the paper towel product has a TS750 value between 19 and 32 dB V2 rms.
In an exemplary embodiment, a basis weight of the product is between 39 and 45 grams/m2.
A paper towel product according to an exemplary embodiment of the present invention comprises at least one ply, the paper towel product is through air dried, rolled, and disposable, and a GATS total absorption of the product is between 17.0 grams water/grams of towel and 21.3 grams water/grams of towel.
A paper towel product according to an exemplary embodiment of the present invention comprises at least one ply, the paper towel product is through air dried, rolled, and disposable, and a GATS absorption rate of the product is between 5.0 and 6.6 (l/sec0.5).
A paper towel product according to an exemplary embodiment of the present invention comprises at least one ply, the paper towel product is through air dried, rolled, and disposable, and the CD stretch of the product is between 15.5% and 19.2%.
A paper towel product according to an exemplary embodiment of the present invention comprises at least one ply, the paper towel product is through air dried, rolled, and disposable, and the product has a measured Sdr value between 36 and 60 and a Vvd value between 5 and 14.
A paper towel product according to an exemplary embodiment of the present invention comprises at least one ply, the paper towel product is through air dried, rolled, and disposable, and a TS750 value of the product is between 19 and 32 dB V2 rms.
The features and advantages of exemplary embodiments of the present invention will be more fully understood with reference to the following, detailed description when taken in conjunction with the accompanying figures, wherein:
A two ply rolled Through Air Dried (TAD) paper towel according to an exemplary embodiment of the present invention has exceptionally high total absorption and absorption rate at a low basis weight. The attributes of high absorption and absorption rate are important for a quality paper towel. Further, combining these attributes with low basis weight provides value to the end consumer in terms of performance, cost, and sustainability.
For the purposes of the present disclosure, the term “disposable towel” may be taken to mean a towel without extruded polymers and that is a towel made to be used and discarded. Disposable towel is not a woven cloth or plastic fiber containing towel that is designed to be cleaned and reused.
Paper towel in accordance with exemplary embodiments of the present invention has a unique combination of properties, including a Developed Interfacial Area (“Sdr”) value of greater than about 30, and a Void Volume (“Vvd”) value of greater than about 4. These properties enable the paper towel to deliver the highest absorbency and absorbency rate with the least amount of basis weight. The ability to have high Sdr with high surface smoothness (TS750) is also a unique combination of attributes that provide value to the end consumer as these attributes provide for an absorbent towel that is also smooth to the touch. Another unique property of the present invention is cross direction (“CD”) stretch from about 14% to about 19% or about 16% to about 20%, which increases the durability of the towel.
Suitable ranges of properties for paper towels according to exemplary embodiments of the invention are: Developed Interfacial Area (“Sdr”) between about 30 and about 65 with Void Volume (“Vvd”) between about 4 and about 16 to create a towel with high absorbency and high caliper with relatively low basis weight. In exemplary embodiments, the Sdr may range between 32 to 50 and the Vvd may range between 5 to 11 or the Sdr may range from 35 to 45 and the Vvd may range between 6 to 10. Paper towel CD stretch may range between 14% to 19 or 16% to 20%. Paper towel caliper may range between 650 to 1200 microns or 750 to 950 microns, and basis weight may range between 35 gsm to 50 gsm or 35 gsm to 45 gsm or 38 gsm to 50 gsm or 38 gsm to 49 gsm or 38 gsm to 48 gsm or 38 gsm to 47 gsm or 38 gsm to 46 gsm or 38 gsm to 45 gsm or 38 gsm to 44 gsm or 38 gsm to 43 gsm or 38 gsm to 42 gsm or 38 gsm to 41 gsm or 38 gsm to 40 gsm. Gravimetric Absorption Testing System (“GATS”) absorbency may range from about 14 g/g to about 17 g/g or 15 g/g to 16 g/g or 13.5 g/g to 16.5 g/g. The GATS absorption rate may range between about 5 to about 7 or 4.5 to 6 l/sec0.5. Softness/smoothness TS750 may range between about 19 to about 40 or 20 to 30 or 19 to 50 or 25 to 45 dB V2 rms.
Without being bound by theory, the unique properties of low basis weight, high absorbency, smooth surface, large void volume as measured by Vvd, high absorbency, good durability with low fiber content and high caliper is made possible by the soft nip transfer of the overlaid TAD structuring belt used in accordance with exemplary embodiments of the present invention. It is believed that the compression of the top layer of the TAD belt and the paper in the pressure roll nip creates a unique paper due to flexing of the sheet and delamination of the fibers during transfer from the TAD fabric to the Yankee and further delamination of the sheet during creping. The delamination of the sheet is not random in this process because the strength of the final product is still high. The unique structure of the fiber distribution provides the paper properties stated above. The combination of paper properties are unique and desired by the end consumer. In exemplary embodiments, the present invention arises from a structure that enables improved quality properties with lower basis weight.
In an exemplary embodiment, the paper towel product is made on a papermaking machine in accordance with a through air dried process using a structured fabric made up of a web contacting layer and a support layer.
In exemplary embodiment, the web contacting layer of the structured fabric may have the following attributes:
Number of MD elements: 12 to 24 per inch, preferably 14 to 20 per inch, most preferably 14 to 18 per inch;
Number of CD elements: 6 to 20 per inch, preferably 10 to 18 per inch, most preferably 12 to 16 per inch;
Width of MD elements: 0.35 mm to 0.65 m, preferably 0.40 mm to 0.60 mm, most preferably 0.45 mm to 0.55 mm;
Width of CD elements: 0.35 mm to 0.65 mm, preferably 0.40 mm to 0.60 mm, most preferably 0.45 mm to 0.55 mm;
Mesh: 12 to 24, preferably 14 to 20, most preferably 14 to 18;
Count: 6 to 20, preferably 10 to 18, most preferably 12 to 16;
Contact Area (static—not under load): 20% to 38%, preferably 25% to 35%, most preferably 28% to 38%;
Contact Area (under load): 40% to 60%, preferably 42% to 56%, most preferably 44% to 50%;
Distance between MD elements: 1.20 mm to 1.70 mm, preferably 1.30 mm to 1.60 mm, most preferably 1.40 mm to 1.50 mm;
Distance between CD elements: 1.40 mm to 1.90 mm, preferably 1.50 mm to 1.80 mm, most preferably 1.60 mm to 1.70 mm;
Overall Pocket Depth: 0.50 mm to 0.80 m, preferably 0.55 mm to 0.70 mm, most preferably 0.58 mm to 0.65 mm;
Pocket Depth from top surface of netting to CD mid rib: 0.25 mm to 0.60 m, preferably 0.32 mm to 0.58 mm, most preferably 0.36 mm to 0.46 mm;
Permeability: 300 cfm to 700 cfm, preferably 350 cfm to 600 cfm, most preferably 400 cfm to 550 cfm;
Caliper: 1.10 mm to 1.60 mm, preferably 1.22 mm to 1.50 mm, most preferably 1.30 mm to 1.45 mm;
Peel force (from supporting layer): 1400 gf/in to 2800 gf/in, preferably 1600 gf/in to 2600 gf/in, most preferably 1800 gf/in to 2400 gf/in;
Embedment Distance (into supporting layer): 0.12 mm to 0.30 mm, preferably 0.16 mm to 0.27 mm, most preferably 0.19 mm to 0.25 mm; and
Tension applied during lamination with supporting layer: 0.25 pli to 0.75 pli, preferably 0.32 pli to 0.65 pli, most preferably 0.40 pli to 0.55 pli.
In exemplary embodiments, the supporting layer of the structured fabric may have the following attributes:
Cross section of rectangular MD yarn: 0.15 mm×0.12 mm to 0.42 mm×0.37 mm, preferably 0.18 mm×0.15 mm to 0.39 mm×0.34 mm, most preferably 0.21 mm×0.18 mm to 0.36 mm×0.31 mm;
Yarns/Inch of MD yarn: 40 to 70, preferably 45 to 65, most preferably 50 to 60;
Thickness of CD yarn: 0.25 mm to 0.55 mm, preferably 0.28 mm to 0.50 mm, most preferably 0.30 mm to 0.45 mm;
Yarns/Inch of CD yarn: 25 to 65, preferably 30 to 55, most preferably 35 to 50;
Weave Pattern: 5 shed weave with 3 MD yarns over 2 CD yarns; preferably 5 shed weave with 2 MD yarns over 3 CD yarns; most preferably 5 shed weave with 1 MD yarn over 4 CD yarns;
Air Permeability: 500 cfm to 900 cfm, preferably 575 cfm to 800 cfm, most preferably 625 cfm to 725 cfm;
Percent carbon black in the MD warp yarns: 8% to 28%, preferably 10% to 22%, most preferably 12% to 16%; and
Percent carbon black in the CD weft yarns: 25% to 55%, preferably 30% to 50%, most preferably 35% to 45%.
In exemplary embodiments, the parameters of the laser used to laminate the web contacting layer with the supporting layer may be as follows:
Power Level: 120 watts to 200 watts, preferably 135 watts to 185 watts, most preferably 150 watts to 170 watts;
Weld Speed: 20 mm/sec to 80 mm/sec, preferably 30 mm/sec to 70 mm/sec, most preferably 40 mm/sec to 60 mm/sec;
Line Width: 0.20 mm to 0.50 mm, preferably 0.25 mm to 0.45 mm, most preferably 0.30 mm to 0.40 mm; and
Overlap Width: 0.25 mm to 2.25 mm, preferably 0.50 mm to 1.75 mm, most preferably 0.75 mm to 1.25 mm.
In exemplary embodiments, the furnish supplied to the headbox of the papermaking machine may have the following characteristics:
Percent of fiber types in each layer: Each layer can be from 20-60% hardwood and 40-80% softwood;
Rates of conical refiner: On hardwood refiner—0 to 60 kwh/ton, on softwood refiner—20-120 kwh/ton;
Amount of Kymene added to each layer: 0-12 kg/ton, or more preferably 3-9 kg/ton, or most preferably 6-9.5 kg/ton;
Amount of Luredur 555 added to each layer: 0-12 kg/ton, or more preferably 3-9 kg/ton, or most preferably 3-6 kg/ton
Amount of Hercobond 2800 added to each layer: 0-8 kg/ton, or more preferably 3-8 kg/ton, or most preferably 4-7 kg/ton; and
Amount of Hercobond 6950 added to each layer: 0-3 kg/ton, or more preferably 1-2 kg/ton.
To impart wet strength to the absorbent structure in the wet laid process, typically a cationic strength component such as Kymene 5377 is added to the furnish during stock preparation. The cationic strength component can include any polyethyleneimine, polyethylenimine, polyaminoamide-epihalohydrin (preferably epichlorohydrin), polyamine-epichlorohydrin, polyamide, polyvinylamine, or polyvinylamide wet strength resin. Useful cationic thermosetting polyaminoamide-epihalohydrin (“PAE”) and polyamine-epichlorohydrin resins are disclosed in U.S. Pat. Nos. 5,239,047, 2,926,154, 3,049,469, 3,058,873, 3,066,066, 3,125,552, 3,186,900, 3,197,427, 3,224,986, 3,224,990, 3,227,615, 3,240,664, 3,813,362, 3,778,339, 3,733,290, 3,227,671, 3,239,491, 3,240,761, 3,248,280, 3,250,664, 3,311,594, 3,329,657, 3,332,834, 3,332,901, 3,352,833, 3,248,280, 3,442,754, 3,459,697, 3,483,077, 3,609,126, 4,714,736, 3,058,873, 2,926,154, 3,877,510, 4,515,657, 4,537,657, 4,501,862, 4,147,586, 4,129,528, 3,855,158, 5,017,642, 6,908,983, 5,171,795, and 5,714,552, the contents of which are incorporated herein by reference in their entirety. Cationic thermosetting PAE resins are the most widely used wet strength resins in wet laid absorbent structures such as paper towel, napkin and facial tissue due to the chemistries ability to generate a high amount of wet strength at an affordable dosage.
As discussed, to impart wet strength to the absorbent structure in a wet laid process, a cationic strength component may be added to the furnish during stock preparation. To impart capacity for the cationic strength resins it is well known in the art to add water soluble carboxyl containing polymers to the furnish in conjunction with the cationic resin. Suitable carboxyl containing polymers include carboxymethylcellulose (“CMC”) as disclosed in U.S. Pat. Nos. 3,058,873, 3,049,469 and 3,998,690, the contents of which are incorporated herein by reference in their entirety.
In accordance with exemplary embodiments, the method involves the use of ultra-high molecular weight (“UHMW”) glyoxalated polyvinylamide adducts (“GPVM”) and/or high molecular weight (“HMW”), glyoxalated polyacrylamide and/or high cationic charge glyoxalated polyacrylamide (“GPAM”) copolymers such as Luredur 555 and high molecular weight (“HMW”) anionic polyacrylamide (“APAM”) such as Hercobond 2800, which are mixed with the furnish during stock preparation of a wet laid papermaking process. HMW APAM is defined as having a molecular weight greater than 500,000 Daltons and can be an inverse emulsion product or a solution product, with a solution product being preferred. Methods to produce UHMW GPVM are documented in U.S. Pat. No. 7,875,676 B2 and U.S. Pat. No. 9,879,381 B2, the contents of which are incorporated herein by reference in their entirety. These patents also characterize the polymer and the prepolymers including the molecular weight. Methods to produce high cationic charge UMW GPAM copolymers are documented in U.S. Pat. No. 9,644,320, the contents of which are incorporated herein by reference in their entirety. This patent also characterizes the polymers and the prepolymers including the molecular weight. The standard viscosity of the APAM copolymer (measured from 0.1 weight-% polymer solution in 1 M NaCl at 25° C. using a Brookfield viscometer with a UL adapter at 60 rpm) may be less than 1.5 or less than 1.6 or less than 1.7 or less than 1.8. The combination of these two or three or more chemistries (referred herein as wet strength agents) provides wet tensile strength of at least 15%, for example 20% or 25% or 30% or 40% or 50% or 60% of the value of the dry tensile strength of the absorbent product measured either in a cross direction or machine direction of the absorbent product. In embodiments, polyvinylamine (PVAM) chemistries such as Hercobond 6950 can also greatly enhance the effectiveness of the wet strength system, as well.
All paper testing is conducted on prepared samples (cut to proper size) that have been conditioned for a minimum of 2 hours in a conditioned room at a temperature of 23+−1.0 deg Celsius, and 50.0%+−2.0% Relative Humidity. The exception is softness testing which requires 24 hours of conditioning at 23+−1.0 deg Celsius, and 50.0%+−2.0% Relative Humidity.
The Ball Burst of a 2-ply tissue or towel web was determined using a Tissue Softness Analyzer (TSA), available from emtec Electronic GmbH of Leipzig, Germany using a ball burst head and holder. The instrument is calibrated every year by an outside vendor according to the instrument manual. The balance on the TSA was verified and/or calibrated before burst analysis. The balance was zeroed once the burst adapter and testing ball (16 mm diameter) were attached to the TSA. The testing distance from the testing ball to the sample was calibrated. A 112.8 mm diameter circular punch was used to cut out five round samples from the web. One of the samples was loaded into the TSA, with the embossed surface facing up, over the holder and held into place using the ring. The ball burst algorithm “Berst Resistance” was selected from the list of available softness testing algorithms displayed by the TSA. The ball burst head was then pushed by the TSA through the sample until the web ruptured and calculated the force in Newtons required for the rupture to occur. The test process was repeated for the remaining samples and the results for all the samples were averaged then converted to grams force.
For more detailed description for operating the TSA, measuring ball burst, and calibration instructions refer to the “Leaflet Collection” or “Operating Instructions” manuals provided by emtec.
The Wet Ball Burst of a 2-ply tissue or towel web was determined using a Tissue Softness Analyzer (TSA), available from emtec Electronic GmbH of Leipzig, Germany using a ball burst head and holder. The instrument is calibrated every year by an outside vendor according to the instrument manual. The balance on the TSA was verified and/or calibrated before burst analysis. The balance was zeroed once the burst adapter and testing ball (16 mm diameter) were attached to the TSA. The testing distance from the testing ball to the sample was calibrated. A 112.8 mm diameter circular punch was used to cut out five round samples from the web. One of the samples was loaded into the TSA, with the embossed surface facing up, over the holder and held into place using the ring. The ball burst algorithm “Berst Resistance” was selected from the list of available softness testing algorithms displayed by the TSA. One milliliter of water was placed onto the center of the sample using a pipette and 30 seconds was allowed to pass before beginning the measurement. The ball burst head was then pushed by the TSA through the sample until the web ruptured and calculated the force in Newtons required for the rupture to occur. The test process was repeated for the remaining samples and the results for all the samples were averaged then converted to grams force.
For more detailed description for operating the TSA, measuring ball burst, and calibration instructions refer to the “Leaflet Collection” or “Operating Instructions” manuals provided by emtec
A Thwing-Albert EJA series tensile tester, manufactured by Thwing Albert of West Berlin, N.J., an Instron 3343 tensile tester, manufactured by Instron of Norwood, Mass., or other suitable vertical elongation tensile testers, which may be configured in various ways, typically using 1 inch or 3 inch wide strips of tissue or towel can be utilized. The instrument is calibrated every year by an outside vendor according to the instrument manual. Jaw separation speed and distance between jaws (clamps) is verified prior to use, and the balance “zero'ed”. A pretension or slack correction of 5 N/m must be met before beginning of elongation measurement. After calibration, 6 strips of 2-ply product are cut using a 25.4 mm×120 mm die. When testing MD (Machine Direction) tensile strength, the strips were cut in the MD direction. When testing CD (Cross Machine Direction) tensile strength, the strips were cut in the CD direction. One of the sample strips was placed in between the upper jaw faces and clamped before carefully straightening (without straining the sample) and clamping the sample (hanging feely from the upper jaw) between the lower jaw faces with a gap or initial test span of 5.08 cm (2 inches). Using a jaw separation speed of 2 in/min, a test was run on the sample strip to obtain tensile strength and peak stretch (as defined by TAPPI T-581 om-17). The test procedure was repeated until all the samples were tested. The values obtained for the six sample strips were averaged to determine the tensile strength and peak stretch in the MD and CD direction. When testing CD wet tensile, the strips were placed in an oven at 105 degrees Celsius for 5 minutes and saturated with 75 microliters of deionized water at the center of the strip across the entire cross direction immediately prior to pulling the sample.
Using a dye and press, six 76.2 mm by 76.2 mm square samples were cut from a 2-ply product being careful to avoid any web perforations. The samples were placed in an oven at 105 deg C. for a minimum of 3 minutes before being immediately weighed on an analytical balance to the fourth decimal point. The weight of the sample in grams was multiplied by 172.223 to determine the basis weight in grams/m2. The samples were tested individually, and the results were averaged. The balance should be verified before use and calibrated every year by an outside vendor according to the instrument manual.
A Thwing-Albert ProGage 100 Thickness Tester Model 89-2012, manufactured by Thwing Albert of West Berlin, N.J. was used for the caliper test. The instrument is verified before use and calibrated every year by an outside vendor according the instrument manual. The Thickness Tester was used with a 2 inch diameter pressure foot with a preset loading of 95 grams/square inch, a 0.030 inch/sec measuring speed, a dwell time of 3 seconds, and a dead weight of 298.45 g. Six 100 mm×100 mm square samples were cut from a 2-ply product with the emboss pattern facing up. The samples were then tested individually, and the results were averaged to obtain a caliper result in microns.
A Thwing-Albert ProGage 100 Thickness Tester Model 89-2012, manufactured by Thwing Albert of West Berlin, N.J. was used for the caliper test. The instrument is verified before use and calibrated every year by an outside vendor according the instrument manual. The Thickness Tester was used with a 2 inch diameter pressure foot with a preset loading of 95 grams/square inch, a 0.030 inch/sec measuring speed, a dwell time of 3 seconds, and a dead weight of 298.45 g. Six 100 mm×100 mm square samples were cut from a 2-ply product with the emboss pattern facing up. Each sample was placed in a container that had been filled to a three inch level with deionized water. The container was large enough where the sample could be placed on top of the water without having to fold the sample. The sample sat in the water in the container for 30 seconds, before being removed and then tested for caliper using the ProGage. The samples were tested individually, and the results were averaged to obtain a wet caliper result in microns.
Softness of a 2-ply tissue or towel web was determined using a Tissue Softness Analyzer (TSA), available from emtec Electronic GmbH of Leipzig, Germany. The TSA comprises a rotor with vertical blades which rotate on the test piece to apply a defined contact pressure. Contact between the vertical blades and the test piece creates vibrations which are sensed by a vibration sensor. The sensor then transmits a signal to a PC for processing and display. The frequency analysis in the range of approximately 200 to 1000 Hz represents the surface smoothness or texture of the test piece and is referred to as the TS750 value. A further peak in the frequency range between 6 and 7 kHz represents the bulk softness of the test piece and is referred to as the TS7 value. Both TS7 and TS750 values are expressed as dB V2 rms. The stiffness of the sample is also calculated as the device measures deformation of the sample under a defined load. The stiffness value (D) is expressed as mm/N. The device also calculates a Hand Feel (HF) number with the value corresponding to a softness as perceived when someone touches a sample by hand (the higher the HF number, the higher the softness). The HF number is a combination of the TS750, TS7, and stiffness of the sample measured by the TSA and calculated using an algorithm which also requires the caliper and basis weight of the sample. Different algorithms can be selected for different facial, toilet, and towel paper products. Before testing, a calibration check should be performed using “TSA Leaflet Collection No. 9” available from emtec. If the calibration check demonstrates a calibration is necessary, “TSA Leaflet Collection No. 10” is followed.
A 112.8 mm diameter round punch was used to cut out five samples from the web. One of the samples was loaded into the TSA, clamped into place (outward facing or embossed ply facing upward), and the TPII algorithm was selected from the list of available softness testing algorithms displayed by the TSA when testing bath tissue and the Facial II algorithm was selected when testing towel. After inputting parameters for the sample (including caliper and basis weight), the TSA measurement program was run. The test process was repeated for the remaining samples and the results for all the samples were averaged and the average HF number recorded.
For more detailed description for operating the TSA, measuring softness, and calibrations refer to the “Leaflet Collection” or “Operating Instructions” manuals provided by emtec.
An M/K GATS (Gravimetric Absorption Testing System), manufactured by M/K Systems, Inc., of Peabody, Mass., USA was used to test absorbency using MK Systems GATS Manual from Jun. 29, 2020. The instrument is calibrated annually by an outside vendor according to the manual. Absorbency is reported as grams of water absorbed per gram of absorbent product. The following steps were followed during the absorbency testing procedure:
Turn on the computer and the GATS machine. The main power switch for the GATS is located on the left side of the front of the machine and a red light will be illuminated when power is on. Ensure the balance is on. A balance should not be used to measure masses for a least 15 minutes from the time it is turned on. Open the computer program by clicking on the “MK GATS” icon and click “Connect” once the program has loaded. If there are connectivity issues, make sure that the ports for the GATS and balance are correct. These can be seen in Full Operational Mode. The upper reservoir of the GATS needs to be filled with Deionized water. The Velmex slide level for the wetting stage was set at 6.5 cm. If the slide is not at the proper level, movement of it can only be accomplished in Full Operational Mode. Click the “Direct Mode” check box located in the top left of the screen to take the system out of Direct Mode and put into Full Operational Mode. The level of the wetting stage is adjusted in the third window down on the left side of the software screen. To move the slide up or down 1 cm at a time, the button for “1 cm up” and “1 cm down” can be used. If a millimeter adjustment is needed, press and hold the shift key while toggling the “1 cm up” or “1 cm down” icons. This will move the wetting stage 1 mm at a time. Click the “Test Options” Icon and ensure the following set-points are inputted: “Dip Start” selected with 10.0 mm inputted under “Absorption”, “Total Weight change (g)” selected with 0.1 inputted under “Start At”, Rate (g) selected with 0.05 inputted per (sec) 5 under “End At” on the left hand side of the screen, “Number of Raises” 1 inputted and regular raises (mm) 10 inputted under “Desorption”, Rate (g) selected with −0.03 inputted per 5 sec under “End At” on the right hand side of the screen. The water level in the primary reservoir needs to be filled to the operational level before any series of testing. This involves the reservoir and water contained in it to be set to 580 grams total mass. Click on the “Setup” icon in the box located in the top left of the screen. The reservoir will need to be lifted to allow the balance to tare or zero itself. The feed and draw tubes for the system are located on the side and extend into the reservoir. Prior to lifting the reservoir, ensure that the top hatch on the balance is open to keep from damaging the top of the balance or the elevated platform that the sample is weighed on. Open the side door of the balance to lift the reservoir. Once the balance reading is stable a message will appear to place the reservoir again. Ensure that the reservoir doesn't make contact with the walls of the balance. Close the side door of the balance. The reservoir will need to be filled to obtain the mass of 580 g. Once the reservoir is full, the system will be ready for testing. Obtain a minimum number of four 112.8 mm diameter circular samples. Three will be tested with one extra available. Enter the pertinent sample information in the “Enter Material ID.” section of the software. The software will automatically date and number the samples as completed with any used entered data in the center of the file name. Click the “Run Test” icon. The balance will automatically zero itself. Place the pre-cut sample on the elevated platform, making sure the sample isn't in contact with the balance lid. Once the balance load is stabilized, click “Weigh”. Move the sample to the aluminum test plate on the wetting stage, centered with the emboss facing down. Ensure the sample doesn't touch the sides and place the cover on the sample. Click “Wet the Sample”. The wetting stage will drop the preset distance to initiate absorption (10 mm). The absorption will end when the rate of absorption is less than 0.05 grams/5 seconds. When absorption stops, the wetting stage will rise to conduct desorption. Data for desorption isn't recorded for tested sample. Remove the saturated sample and dry the wetting stage prior to the next test. Once the test is complete, the system will automatically refill the reservoir. Record the data generated for this sample. The data that is traced for each sample is the dry weight of the sample (in grams), the normalized total absorption of the sample reflected in grams of water/gram of product and the normalized absorption rate in grams of water per second. The GATS absorption rate is defined as the speed at which the towel sample absorbs the water as defined by the best fit plot on the GATS absorption curve. This is a standard value plotted and reported by the GATS software in units of 1/sec05. The higher this value is, the faster the water is being absorbed by the towel sample. Repeat procedure for the three samples and report the average total absorbency.
A wet scrubbing test was used to measure the durability of a wet towel. The test involved scrubbing a sample wet towel with an abrasion tester and recording the number of revolutions of the tester it takes to break the sample. Multiple samples of the same product were tested and an average durability for that product was determined. The measured durability was then compared with similar durability measurements for other wet towel samples.
An abrasion tester was used for the wet scrubbing test. The particular abrasion tester that was used was an M235 Martindale Abrasion and Pilling Tester (“M235 tester”) from SDL Atlas Textile Testing Solutions. The M235 tester provides multiple abrading tables on which the samples are abrasion tested and specimen holders that abrade the towel samples to enable multiple towel samples to be simultaneously tested. A motion plate is positioned above the abrading tables and moves the specimen holders proximate the abrasion tables to make the abrasions.
In preparation for the test, eight (8) towel samples, approximately 140 mm (about 5.51 inches) in diameter, were cut. Additionally, four (4) pieces, also approximately 140 mm (approximately 5.51 inches) in diameter, were cut from an approximately 82±1 μm thick non-textured polymer film. The non-textured side of a Ziploc® Vacuum Sealer bag from SC Johnson was used as the non-textured polymer film. However, any non-textured polymer film, such as high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), or polyester, to name a few, could be used. Additionally, four (4) 38 mm diameter circular pieces were cut from a textured polymer film with protruding passages on the surface to provide roughness. The textured polymer film that is used for this test is the textured side of a Ziploc® Vacuum Sealer bag from SC Johnson. The textured film has a square-shaped pattern (
An example of an abrading table used in conjunction with the M235 tester is shown in
Referring to
The M235 tester was then turned on and set for a cycle time of 200 revolutions. 0.5 mL of water was placed on each towel sample. After a 30 second wait, the scrubbing test was initiated, thereby causing the specimen holder 206 to rotate 200 revolutions. The number of revolutions that it took to break each sample on the respective abrading table 202 (the “web scrubbing resistance” of the sample) was recorded. The results for the samples of each product were averaged and the products were then rated based on the averages.
Void Volume relative to a specified depth (Vvd) is the volume-per-unit-area of all surface features below a user-defined depth threshold. The depth threshold was set to be 250 micrometers below the mean plane of the filtered surface data. Vvd is reported as “cubic micrometers per square micrometer” which reduces to simple micrometers.
A depth threshold of 250 micrometers is selected for Vvd. Prior to the calculation of Vvd, the surface data is levelled with a least squared plane and filtered to suppress wavelengths shorter than 0.08 mm and also suppress wavelengths longer than 8.0 mm. This filtering process results in a band-limited surface and provides the Z=0.0 reference for thresholding.
The developed interfacial area (Sdr) can be further understood by referencing ISO 25178-2, the contents of which are incorporated herein by reference in their entirety. Sdr is reported as a percent increase in surface area due to roughness.
Surface images used to calculate the Vvd and Sdr were acquired using a Keyence Model VR-3200 G2 3D Macroscope equipped with motorized XY stage, VR-3000K controller, VR-H2VE version 2.2.0.89 Viewer software, and VR-H2AE Analyzer software. After following calibration procedures, as outlined by the Keyence equipment manual from 2016, the instrument was configured for 25× magnification with display units as mm. The following was selected on the viewer software: “Expert mode” for viewer capture method, and “normal” capture image type for Camera settings. For Measurement settings: “Glare removal” mode was selected with “both sides” measurement direction, Adjust brightness for measurement set to “Auto,” and Display missing and saturated data turned “ON.” This results in an “optical surface data set” which is approximately 12.1 mm (X direction) by 9.1 mm (Y direction) with a pixel size of approximately 7.9 microns.
On paper towels, the top surface of the top ply is the surface of interest, avoiding any and all emboss points if possible. Embossments are not representative of the majority of the surface and should be avoided during the “optical surface data set” acquisition. A representative paper towel sheet was torn from the center of a roll and held in place using weights. This test was performed under ambient office temperature and humidity. When tearing the sheet from the roll, care was taken to not alter the topographic features of the sample. The machine direction (MD) of the sample was placed in the Y axis (front to back on the stage as seen from operator perspective in front of the system) while the cross direction (CD) was placed in the X axis (left to right on the stage as seen from operator perspective in front of the system). Care was taken to ensure no creases or folds were present in the sample and the sample was not under any MD or CD directional stress. The image was autofocused prior to capturing the “optical surface data set”. Three of these “optical surface data sets” were collected for each sample and the average Sdr and the average Vvd parameters are reported for the three datasets. The average values are reported as the measured values for each sheet.
“Optical surface data sets” were exported from the analyzer software with image type “Height” and the “No Skip” option selected. These “optical surface data sets” were analyzed with OmniSurf3D (v1.03.060) software, available from Digital Metrology Solutions, Inc. of Columbus, Ind., USA for parameter calculations.
The OmniSurf3D settings were set as follows:
Preprocessing:
Geometry:
Filtering:
Short Wavelength Limitation: Gaussian/0.0800 mm/Sync X&Y
Long Wavelength Limitation: 2nd Order Gaussian/8.0000 mm/Sync X&Y
Post-Filter Edge Discarding: None
The Pre-processing settings are shown in
The settings described above were chosen to remove underlying curvatures and to suppress short wavelength noise in the samples—thereby providing a well controlled spatial wavelength regime.
In the “Parameters” tab of the “analysis settings,” the parameters “Sdr” and “Vvd” were chosen. The Vvd threshold is set to −250 micrometers relative to the surface mean as shown in
An Instron Tensile Tester with two clamps was used to perform the peel force test. Narrow strips were cut from the belt in the machine direction (MD) or cross-machine direction (CD), each 4 in. long (100 mm). Initially, a small portion of the belt was peeled apart by hand, and then a strip from the papermaking top fabric and the woven bottom fabric was each placed in opposite clamps. The setting was set from 10 mm-90 mm of movement from the original length (10% to 90%) and a speed setting of 300 mm/min, and the Instron was started to peel the two strips from each other, while measuring the peel force result in N. The result was then converted to gf by multiplying by 102 unit conversion.
To calculate embedment distance, a series of measurements was performed using an AMES model AQD-2110 (1644 Concord Street in Framingham Mass. 01701, Tel #781 893-0095) caliper measurement device. The web contacting layer was manually peeled away and detached from the woven supporting layer, until a large, flat area (devoid of any wrinkles or creases) was produced, suitably sized for taking multiple measurements at different points. Using the AMES device, at least five (5) caliper readings were taken at different points on the exposed woven supporting layer. Those measurements were averaged together and recorded. The plunger was not allowed to strike the material being measured, as this would artificially reduce the caliper. The plunger was allowed to gently contact the material. Next, the same series of five (5) caliper readings was performed on the web contacting layer which was peeled away from the woven supporting layer. Those measurements were averaged together and recorded. Finally, the total thickness of the composite/laminated belt was measured. Five (5) caliper readings were taken, widely spaced, from a piece of composite/laminated belt which still had the web contacting layer embedded into the woven supporting layer and which had not been peeled or disturbed. Those measurements were averaged together and recorded.
Theoretically, a fabric which has achieved no embedment of the web contacting layer into the woven supporting layer will have a total thickness equal to the web contacting layer thickness plus the woven supporting layer thickness. Using the data collected previously in this procedure, the zero-embedment value was calculated by adding the average web contacting layer thickness to the average woven supporting layer thickness, and recording this number.
To calculate the total embedment, the total measured thickness value was subtracted from the zero-embedment thickness value. The difference between those two numbers is the distance to which the web contacting layer had become embedded in the woven supporting layer.
To calculate shear number, samples were prepared by the following method. First, cut two samples from the composite belt or fabric, one at a 45 degree angle to the weft line, the second at a 135 degree angle to the weft line. These samples are to be 2.0±0.1 inches wide by a minimum of 9 inches long.
Next, mount the sample in the clamps of a Constant Rate Extension (CRE) testing machine such as an Instron 3343 tensile tester, manufactured by Instron of Norwood, Mass. The CRE machine is to be set at a 6.0 inch gauge length, a crosshead speed of 1 inch/minute, and a load range of 3.0 lbs, with a 100 lb load cell recommended. Cycle the CRE machine from 0 to 2 lbs/inch, then back to 0. Shear number is determined by measuring the fabric elongation between 0.5 to 2 lbs/inch of loading. The average shear number will be determined as the average of the 45 degree and 135 degree sample values. A higher Shear Number equates to a fabric that is generally more stable, less flexible, and demonstrates a higher resistance to shear forces or movement, while the converse or lower Shear Number, equates to a fabric that is less stable, more flexible, and demonstrates a lower resistance to shear forces or movement.
Shear number may be calculated according to formula (1) as follows:
Shear Number=(Load Range×Gauge Length)/(Fabric Elongation×Sample Width). (1)
Applying formula (1) in this case results in the following calculation:
Shear Number=(3 lbs×6 in.)/(Fabric Elongation×2 in.)
This simplifies to Shear Number=9 (lbs)× Fabric Elongation (inches)
The fabric elongation is a measured output of the test. For this example, the fabric elongation was measured at 0.195 inches, then Shear Number=9 lbs/0.0.195 in.=46 lbs/in.
Permeability was tested by following the manual instructions of the TEXTEST FX 3300 LabAir IV available from TEXTEST AG, CH-8603 Schwerzenbach, Switzerland. The instrument works in accordance with ASTM D 737 test method, Standard Test Method for Air Permeability of Textile Fabrics. For the ASTM D 737 test method, test area of 38 cm2, test pressure of 125 Pa, and ft3/ft2/min for unit of measure were selected. The unit was reset to zero. The sample was loaded and the test was started by pressing down the clamping arm. The test sample was clamped to the test head and the vacuum pump automatically started. The orifice plate within the unit automatically adjusted to select the proper orifice size and opening for the air flow and permeability range of the sample. The reading was saved once the air flow reached a constant level. Five (5) different samples were tested and each test was recorded on the print out.
The wound caliper in microns is the calculated caliper of the paper towel in the rolled form before being removed from the roll. Wound caliper can be calculated in accordance with formula (2) as follows:
WOUND CALIPER=(((Π*ROLL DIAMETER/2*ROLL DIAMETER/2)−(Π*CORE DIAMETER/2*CORE DIAMETER/2))/(SHEET COUNT*SHEET LENGTH))*1000. (2)
(Roll Diameter, Core Diameter, Sheet Length in Mm).
The following Examples and Comparative Examples illustrate advantages of the present invention. Process parameters, fabric properties and towel product properties described in the Examples are not intended to be limiting to the present invention. Various properties of the paper towel products described in the Examples and Comparative Example, as well as that of competitor products, are provided in Tables 1 and 2 (
A laminated composite fabric with a web contacting layer made up of an extruded netting of thermoplastic polyurethane (TPU) 16×14 (16 machine direction elements per inch by 14 cross-direction elements per inch in the top web contacting layer) was provided.
The composite belt was used on a TAD machine with a three layer headbox. The towel web was multilayered with the three layers from top to bottom labeled as air, core, and dry. The air layer is the outer layer that is transferred to the TAD fabric from the inner forming fabric. The dry layer is the outer layer that is closest to the surface of the Yankee dryer and the core is the center layer of the towel web. Each of the three layers were prepared using 50% eucalyptus (Euc) fiber purchased from Cenibra (Avenida Afonso Pena, 1964 Andar 7 Belo Oriente, MB 30130005 Brazil, phone 55-31-3235-4041), refined in a conical refiner at 30 kwh/metric ton, and 50% Northern Bleached Softwood Kraft (NBSK) fiber purchased from the Grand Prairie mill owned by International Paper (6400 Poplar Ave, Memphis, Tenn. 38197, phone 901-419-9000), refined in a conical refiner at 100 kwh/metric ton. Kymene 5377 (a polyamide-epichlorohydrin resin) at 9.0 kg (dry basis)/metric ton and Luredur 555 (a glyoxylated polyacrylamide) at 4.0 kg (dry basis)/metric ton were added to the NBSK fiber stream after the refiner. After blending the NBSK and EUC fiber, Hercobond 2800 (an anionic polyacrylamide) at 5.0 kg (dry basis)/metric ton was added to the fiber stream. Additionally, 1.5 kg (dry basis)/metric ton of Hercobond 6950 (a polyvinyl amine) was added to each layer to aid in fiber retention prior to the fan pumps. These chemistries can all be purchased from Solenis (3 Beaver Valley Rd ste 500 Wilmington, Del. 19803 phone 506-233-0042).
The furnish (mixture of fiber and chemicals) was diluted to a solids of approximately 0.5% consistency and fed to separate fan pumps which delivered the slurry to a triple layered headbox. The headbox pH was controlled to approximately 7.5 pH by addition of sodium bicarbonate to the stock prior to the fan pumps. The headbox delivered the furnish slurry to a gap former twin wire C-wrap with an outer wire (T-star Max 453, from Asten Johnson 4399 Corporate Rd, Charleston, S.C. 29405, phone #843-747-7800) and inner wire (T-star Max 451, from Asten Johnson). When the fabrics separated, the nascent web followed the inner wire and was dried to approximately 23% moisture using a series of vacuum boxes and steambox.
The web was then transferred using vacuum to the laminated composite TAD fabric described previously with the inner wire running at 1005 m/min and TAD fabric running at approximately 1000 m/min. The vacuum at transfer was −50 kpa using a single slotted vacuum box followed by another vacuum box with 2 slots, the first at −33 kpa, and the second slot a −45 kpa, to help facilitate fiber penetration into the TAD fabric and provide caliper to the nascent web. The web was pre-dried using two through air dried drums, the first drum with a supply air temperature of 175 deg C., and the second drum with a supply air temperature of 140 deg C. The web was then transferred to a Yankee dryer at approximately 85% solids. The Yankee dryer had a chemical package to aid in sticking the web to the dryer and provide adhesion for creping at the crepe blade. The chemical package was the following: 65 total mg/m2 comprised of 52% Rezosol 8207 PVOH (from Solenis), 42% 3222 Adhesive (from Solenis), 4% Rezosol 5150 oil (from Solenis), and 2% monoammonium phosphate. The web was dried to approximately 97.5% solids using the Yankee dryer and installed hot air impingement hoods prior to being creped at a speed differential of 10% using a 65 deg steel blade with a blade holder angle of 25 deg. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
A 2 ply TAD rolled towel was produced in the same manner as Example 1 but the roll was made with a sheet count of 104 sheets, a sheet length of 152.4 mm, a sheet width of 279.4 mm, and a roll diameter of 148 mm. The properties of this two ply TAD rolled towel product is shown as Example 2 in Tables 1 and 2.
The composite belt of Example 1 was used on a TAD machine with a three layer headbox. The towel web was multilayered with the three layers from top to bottom labeled as air, core, and dry. The air layer is the outer layer that is transferred to the TAD fabric from the inner forming fabric. The dry layer is the outer layer that is closest to the surface of the Yankee dryer and the core is the center layer of the towel web. Each of the three layers were prepared using 30% eucalyptus (Euc) fiber purchased from Cenibra, unrefined, 40% Northern Bleached Softwood Kraft (NBSK) fiber from the Grand Prairie mill owned by International Paper and 30% Metsa NBSK from Metsa Fibre (Maanpääntie 9. P.O. BOX 165 FI-26101 RAUMA FINLAND, phone #+358 (0)10 466 8999). The two NBSK fibers were co-refined in a conical refiner at 80 kwh/metric ton. Kymene 5377 (a polyamide-epichlorohydrin resin) at 9.0 kg (dry basis)/metric ton was added to the NBSK fiber stream after the refiner. After blending the NBSK and EUC fiber, Hercobond 2800 (a anionic polyacrylamide) at 5.0 kg (dry basis)/metric ton was added to the fiber stream. Additionally, 1.5 kg (dry basis)/metric ton of Hercobond 6950 (a polyvinyl amine) was added to each layer to aid in fiber retention prior to the fan pumps. These chemistries can all be purchased from Solenis (3 Beaver Valley Rd ste 500 Wilmington, Del. 19803 phone 506-233-0042).
The furnish (mixture of fiber and chemicals) was diluted to a solids of approximately 0.5% consistency and fed to separate fan pumps which delivered the slurry to a triple layered headbox. The headbox pH was controlled to approximately 7.5 pH by addition of sodium bicarbonate to the stock prior to the fan pumps. The headbox delivered the furnish slurry to a gap former twin wire C-wrap with an outer wire (T-star Max 453, from Asten Johnson 4399 Corporate Rd, Charleston, S.C. 29405, phone #843-747-7800) and inner wire (T-star max 451, from Asten Johnson). When the fabrics separated, the nascent web followed the inner wire and was dried to approximately 23% moisture using a series of vacuum boxes and steambox.
The web was then transferred using vacuum to the laminated composite TAD fabric described in Example 1 with the inner wire running at 1005 m/min and TAD fabric running at approximately 1000 m/min. The vacuum at transfer was −50 kpa using a single slotted vacuum box followed by another vacuum box with 2 slots, the first at −35 kpa, and the second slot a −52 kpa, to help facilitate fiber penetration into the TAD fabric and provide caliper to the nascent web. The web was pre-dried using two through air dried drums, the first drum with a supply air temperature of 150 deg C., and the second drum with a supply air temperature of 120 deg C. The web was then transferred to a Yankee dryer at approximately 85% solids. The Yankee dryer has a chemical package to aid in sticking the sheet to the dryer and provide adhesion for creping at the crepe blade. The chemical package was the following: 65 total mg/m2 comprised of 52% Rezosol 8207 PVOH (from Solenis), 42% 3222 Adhesive (from Solenis), 4% Rezosol 5150 oil (from Solenis), and 2% monoammonium phosphate. The web was dried to approximately 97.5% solids using the Yankee dryer and installed hot air impingement hood prior to being creped at a speed differential of 11% using a 65 deg steel blade with a blade holder angle of 25 deg. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
A 2 ply TAD rolled towel was produced in the same manner as Example 3 but the roll was made with a sheet count of 99 sheets, a sheet length of 152.4 mm, a sheet width of 279.4 mm, and a roll diameter of 148 mm. The properties of this two ply TAD rolled towel product is shown as Example 4 in Tables 1 and 2.
A 2 ply TAD rolled towel was produced in the same manner as Example 3 but the roll was made with a sheet count of 125 sheets, a sheet length of 152.4 mm, a sheet width of 279.4 mm, and a roll diameter of 148 mm. The properties of this two ply TAD rolled towel product is shown as Example 4 in Tables 1 and 2.
A laminated composite fabric with a web contacting layer made up of an extruded netting of thermoplastic polyurethane (TPU) 16×6 (16 machine direction elements per inch by 6 cross-direction elements per inch in the top web contacting layer) was provided. The extruded netting had the following characteristics and geometries: machine direction (MD) elements having a width W3 of 0.48 mm and cross direction (CD) elements having a width W2 of 0.86 mm, with a mesh of 16 MD strands per inch and a count of 6 CD strands per inch, contact area of 28% (with the paper web) with solely MD elements in plane in static measurement and 44% contact area (with the paper web) under load (50 kN/m) as the structure compressed and the CD elements moved up into the same plane as the MD elements, due to use of the thermoplastic polyurethane (TPU) elastomeric material. The TPU material is a softer material and measured in the range of 65 to 75 Shore A Hardness while the woven supporting layer comprised of harder PET measured 95 to 105 Shore A Hardness using a portable Mitutoyo Hardmatic HH-300 series, ASTD Shore A Durometer test device calibrated per ASTM D 2240. The distance W1 between MD elements in the web contacting layer was 1.53 mm, and the distance L1 between the CD elements was 4.69 mm. The overall average pocket depth T1 was 0.76 mm with a min of 0.45 mm and a max of 0.95 mm. The pocket depth E1 from the top surface of the netting to the CD mid-rib element was 0.40 mm. The TPU netting had a natural color, the permeability of the TPU laminated belt was 500 CFM with a caliper of 1.27 mm. The peel force required to remove the web contacting layer from the woven supporting layer was 2359 gf/in, and the embedment distance of the web contacting layer into the woven supporting layer was 0.23 mm. The supporting layer had a 0.27×0.22 mm cross-section rectangular MD yarn (or filament) at 56 yarns/inch, and a 0.35 mm thickness CD yarn at 41 yarns/inch. The weave pattern of the base layer was a 5-shed, 1 MD yarn over 4 CD yarns, then under 1 CD yarn, then repeated. The material of the base fabric yarns was 100% PET. The fabric was unsanded, with an air permeability of 675 CFM. The weft yarns received 0.40% carbon black content by weight in the CD, and 0.14% carbon black content by weight in the MD. A 20 percent by weight carbon black master batch was let down into neat polyethylene terephthalate to generate the desired concentration (from 0.4 to 0.14 weight percent) of carbon black in the yarn. The carbon black was evenly mixed by addition of the carbon black to the polymer pellets in a hopper prior to molten extrusion. The TPU netting was placed under 0.50 PLI (pounds per linear inch) of tension as it was being laminated to the supporting layer. The welding laser was purchased from Leister Technologes (1275 Hamilton Parkway Itasca, Ill. 60143). The welding laser was a NOVOLAS Basic AT with fiber-coupled (line-coupled) roll optics with nominal 300 W, 940 nm laser set to 40% power level (161 watts), at a welding head speed of 50 mm/sec and an optical line width of 34 mm with a 1 mm overlap between laser passes (line energy output 3200 J/m).
The composite belt was used on a TAD machine with a three layer headbox. The towel web was multilayered with the three layers from top to bottom labeled as air, core, and dry. The air layer is the outer layer that is transferred to the TAD fabric from the inner forming fabric. The dry layer is the outer layer that is closest to the surface of the Yankee dryer and the core is the center layer of the towel web. Each of the three layers were prepared using 30% eucalyptus (Euc) fiber purchased from Cenibra, unrefined, 40% Northern Bleached Softwood Kraft (NBSK) fiber from the Grand Prairie mill owned by International Paper and 30% Metsa NBSK from Metsa Fibre (Maanpääntie 9. P.O. BOX 165 FI-26101 RAUMA FINLAND, phone #+358 (0)10 466 8999). The two NBSK fibers were co-refined in a conical refiner at 100 kwh/metric ton. Kymene 5377 (a polyamide-epichlorohydrin resin) at 9.0 kg (dry basis)/metric ton was added to the NBSK fiber stream after the refiner. After blending the NBSK and EUC fiber, Hercobond 2800 (a anionic polyacrylamide) at 5.0 kg (dry basis)/metric ton was added to the fiber stream. Additionally, 1.5 kg (dry basis)/metric ton of Hercobond 6950 (a polyvinyl amine) was added to each layer to aid in fiber retention. These chemistries can all be purchased from Solenis (3 Beaver Valley Rd ste 500 Wilmington, Del. 19803 phone 506-233-0042).
The furnish (mixture of fiber and chemicals) was diluted to a solids of approximately 0.5% consistency and fed to separate fan pumps which delivered the slurry to a triple layered headbox. The headbox pH was controlled to approximately 7.5 pH by addition of sodium bicarbonate to the stock prior to the fan pumps. The headbox delivered the furnish slurry to a gap former twin wire C-wrap with an outer wire (T-star Max 453, from Asten Johnson 4399 Corporate Rd, Charleston, S.C. 29405, phone #843-747-7800) and inner wire (Albany Q592, from Albany International 216 Airport Drive Rochester, N.H. 03867 USA Phone Number: 603-330-5850). When the fabrics separated, the nascent web followed the inner wire and was dried to approximately 23% moisture using a series of vacuum boxes and steambox.
The web was then transferred using vacuum to the laminated composite TAD fabric described previously in this Example with the inner wire running at 1005 m/min and TAD fabric running at approximately 1000 m/min. The vacuum at transfer was −30 kpa using a single slotted vacuum box followed by another vacuum box with the one slot at −20 kpa to help facilitate fiber penetration into the TAD fabric and provide caliper to the nascent web. The web was pre-dried using two through air dried drums, the first drum with a supply air temperature of 190 deg C., and the second drum with a supply air temperature of 140 deg C. The web was then transferred to a Yankee dryer at approximately 85% solids. The Yankee dryer had a chemical package to aid in sticking the sheet to the dryer and provide adhesion for creping at the crepe blade. The chemical package was the following: 65 total mg/m2 comprised of 52% Rezosol 8207 PVOH (from Solenis), 42% 3222 Adhesive (from Solenis), 4% Rezosol 5150 oil (from Solenis), and 2% monoammonium phosphate. The web was dried to approximately 97.5% solids using the Yankee dryer and installed hot air impingement hood prior to being creped at a speed differential of 11% using a 65 deg steel blade with a blade holder angle of 25 deg. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
Example 7 was made under the same conditions as Example 6 with the following exceptions: vacuum at transfer to the TAD fabric was conducted using −47 kpa of vacuum; the NBSK was refined at 120 kwh/ton, and the second TAD drum temperature was increased to 150 deg C. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
Example 8 was made under the same conditions as Example 7. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
Example 9 was made under the same conditions as Example 7. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
Example 10 was performed in order to display the surface topography differences that drive Vvd and Sdr values. In order to obtain a higher Vvd (14.312 micron) to Sdr (37.886%) ratio, the general surface topography of the paper towel sheet was smoothed throughout the larger peaks and valleys while still utilizing a similar general surface profile as created in Examples 1 through 9. The smoothing of the surface topography was done digitally. As shown in
Example 11 was also performed in order to display the surface topography differences that drive Vvd and Sdr values. In order to obtain a lower Vvd (5.418 micron) to Sdr (58.174%) ratio, the general surface topography was roughened throughout the larger peaks and valleys while still utilizing a similar general surface profile as created in Examples 1 through 9. The roughening of the surface topography was done digitally. As shown in
A TAD fabric was provided made up of an 8-shed woven fabric, comprised of polyester (PET) with a 40 mesh×28 count. The machine direction (MD) strands had a yarn width of 0.39 mm and cross direction (CD) strands had a yarn width of 0.62 mm, with a contact area of 18%, air permeability of 600 cfm, and caliper of 1.14 mm. The average pocket depth was 0.60 mm. The fabric was used on a TAD machine with a three layer headbox. The towel web was multilayered with the three layers from top to bottom labeled as air, core, and dry. The air layer is the outer layer that is transferred to the TAD fabric from the inner forming fabric. The dry layer is the outer layer that is closest to the surface of the Yankee dryer and the core is the center layer of the towel web. Each of the three layers were prepared using 50% eucalyptus (Euc) fiber purchased from Cenibra, refined in a conical refiner at 10 kwh/metric ton, and 50% Northern Bleached Softwood Kraft (NBSK) fiber from the Grand Prairie mill owned by International Paper refined in a conical refiner at 70 kwh/metric ton. Kymene 5377 (a polyamide-epichlorohydrin resin) at 9.0 kg (dry basis)/metric ton was added to the NBSK fiber stream after the refiner. After blending the NBSK and EUC fiber, Hercobond 2800 (an anionic polyacrylamide) at 5.0 kg (dry basis)/metric ton was added to the fiber stream. Additionally, 1.5 kg (dry basis)/metric ton of Hercobond 6950 (a polyvinyl amine) was added to each layer to aid in fiber retention prior to the fan pumps. These chemistries can all be purchased from Solenis (3 Beaver Valley Rd ste 500 Wilmington, Del. 19803 phone 506-233-0042).
The furnish (mixture of fiber and chemicals) was diluted to a solids of approximately 0.5% consistency and fed to separate fan pumps which delivered the slurry to a triple layered headbox. The headbox pH was controlled to approximately 7.5 pH by addition of sodium bicarbonate to the stock prior to the fan pumps. The headbox delivered the furnish slurry to a gap former twin wire C-wrap with an outer wire (T-star Max 453, from Asten Johnson 4399 Corporate Rd, Charleston, S.C. 29405, phone #843-747-7800) and inner wire (Albany Q592, from Albany International 216 Airport Drive Rochester, N.H. 03867 USA Phone Number: 603-330-5850). When the fabrics separated, the nascent web followed the inner wire and was dried to approximately 23% moisture using a series of vacuum boxes and steambox.
The web was then transferred using vacuum to the TAD fabric described in this Example with the inner wire running at 1065 m/min and TAD fabric running at approximately 1000 m/min. The vacuum at transfer was −37 kpa using a single slotted vacuum box followed by another vacuum box with two slots at −37 kpa and −50 kpa to help facilitate fiber penetration into the TAD fabric and provide caliper to the nascent web. The web was pre-dried using two through air dried drums, the first drum with a supply air temperature of 150 deg C., and the second drum with a supply air temperature of 110 deg C. The web was then transferred to a Yankee dryer at approximately 85% solids. The Yankee dryer had a chemical package to aid in sticking the sheet to the dryer and provide adhesion for creping at the crepe blade. The chemical package was the following: 65 total mg/m2 comprised of 52% Rezosol 8207 PVOH (from Solenis), 42% 3222 Adhesive (from Solenis), 4% Rezosol 5150 oil (from Solenis), and 2% monoammonium phosphate. The web was dried to approximately 97.5% solids using the Yankee dryer and installed hot air impingement hood prior to being creped at a speed differential of 3% using a 65 deg steel blade with a blade holder angle of 25 deg. The web was wound into rolls and then converted into 2-ply finished product towel rolls using the DEKO emboss method with a steel emboss roll patterned as shown in
Now that embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon can become readily apparent to those skilled in the art. Accordingly, the exemplary embodiments of the present invention, as set forth above, are intended to be illustrative, not limiting. The spirit and scope of the present invention is to be construed broadly.
This application claims priority to and the benefit of U.S. Provisional Application No. 63/195,323, filed Jun. 1, 2021 and entitled PAPER TOWEL PRODUCTS AND METHODS OF MAKING THE SAME, the contents of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63195323 | Jun 2021 | US |
