Chemical Products – Zhiying Yu, Siddharth S. Vaijapurkar, Daniel W. Sumnicht, GPCP IP Holdings LLC
Abstract for “Absorbent sheet tail-sealed using nanofibrillated, cellulose-containing tailseal adhesivesA roll of absorbent sheets tail-sealed using an NFC containing an aqueous Tail-seal glue includes an NFC that contains aqueous Tail-seal glue interposed between the tail of the roll and an underlying Convolution of the roll, which attaches the tail to the convolution to form the tail. Nanofibrillatedcellulose is included in the NFC containing tailseal adhesive. It also contains one or more components from the group consisting (i),(ii), and (iii), wherein (iii), is a water-soluble derivative of cellulose; (iii), is a hydrophobic polyol; and (iiii), is a viscosity moderator other than a water-soluble derivative of cellulose; (iv), is PVOH and (v), and a viscosity modification An optional surface tension modifier is included in the NFC that contains tail-seal adhesive.
Background for “Absorbent sheet tail-sealed using nanofibrillated, cellulose-containing tailseal adhesives
Rolls of absorbent sheet, including paper towels and bath tissue, are available. Most bath tissue and paper towels come in rolls of multi-ply tissue shrinkwrapped with polyethylene. When a parent roll of tissue becomes a?log? it is usually attached to the underlying layers to form a tail seal. Tail sealing is used to prevent loose ends from unravelling and interfering in the manufacturing process. It also helps to make the package attractive and allows for easy handling by the consumer of any loose rolls. Improper tail-sealing can lead to many consumer complaints, especially if it makes it difficult to remove the sheet from the roll. Most absorbent sheet products have complaints about improper tail-sealing. Multi-ply products are prone to complaints about ply separation.
“Hot melt adhesives are used to tail-seal absorbent sheets, as shown in U.S. Pat. No. 7,799,402 to Redmann et al. U.S. Pat. No. 4,026,752 to Hartbauer et al. Low solids aqueous compositions can also be used conventionally. U.S. Pat. No. 7,967,933 to Redmann et al. See, also, U.S. Pat. No. No.
The United States Patent Application Publication No. 0090156 describes adhesives for absorbent sheets. US2015/0090156 by Combs et., entitled Adhesives that Include Plasticized Starch Derivatives and Methods and Articles Related Thereto (Celanese Acetate LLC). This reference describes hot melt adhesive compositions based upon starch, cellulose acetate, and/or acetins. It also proposes the use cellulose nanofibrils to fill in and xanthan gum as an optional polymeric component. See, also, U.S. Pat. No. No.
“Despite the availability and variety of adhesive materials, tail-sealing rolled goods is still a major problem for manufacturing and customer satisfaction.
“Aqueous compositions containing nanofibrillatedcellulose and other components have been shown to be extremely effective in tail-sealing absorbent sheet rolls. NFC significantly increases Tail-Seal Bond strength when combined with other components, as opposed to traditional adhesives. Tail-Seal adhesive can be tailored to achieve the best results for any given roll product or converting line. The innovative NFC that contains tail-seal adhesive is composed of nanofibrillatedcellulose and one or several additional components. (i) Is a water-soluble derivative of cellulose; (iii), a hydrosoluble polyol; and (iiii), a viscosity modifier other than a cellulose derivative. (iv), PVOH, and (v). PVOH and viscosity modify. A surface tension modifier, other than PVOH, is optionally included.
The NFC that contains tail-seal adhesives has a superior water retention capability, which may allow for less adhesive penetration. This allows the tail to be easily separated when it is needed again without damaging the roll or causing ply separation. Tail-seal adhesives are especially useful for multi-ply products, where excessive tail seal strength may cause ply seperation when the product is being used.
“The unexpected increases in Tail-Seal bond strength also allow a manufacturer use less adhesive for a product. This allows them to lower converting costs and improve product quality.
“Nevertheless, the discussion that follows will reveal additional features and benefits of the invention.”
“BRIEF DESCRIPTION DES DRAWINGS”
“The invention is described below with reference to drawings, wherein like numerals denote similar parts.
“FIG. 8 is a histogram that shows Tail-Seal Bond Strength of different tissue products using different adhesives.
“FIG. 12 is a histogram that shows the breaking length of NFC I or NFC II, as handsheets or films.
“FIG. 14A shows the surface tension of NFC and tap water.
“FIG. 14B is a plot that shows the surface tensions of different compositions;
“FIGS. 17-20 are plots showing Viscosity and shear rates for different bonding agents.
“The invention is described below in connection to the Figures only for illustration purposes. The appended claims define the invention. The following terminology is used in accordance with the exemplary definitions. mg stands for milligrams, m2 stands for square meters, and Fpm stands for feet per minute.
“Adhesive viscosity” is measured at room temperatures using a cone-plate geometry.
The “Characteristic Breaking Longth of NFC Material” is determined by testing a sheet of NFC material as described in this article.
“Characteristic nanofiber viscosity is measured using a 1Wt% suspension of NFC in water, as further explained herein.”
“?Consisting essentially? Similar terminology refers only to the recited components. It excludes any other ingredients that would significantly alter the fundamental and unique characteristics of the composition. A composition or article is essentially composed of the listed or recited components, unless otherwise stated or readily apparent. This means that the terminology does not include more than 10% of unrecited components.
A surface tension modifier is an agent that reduces the surface tension in an aqueous composition. Depending on the requirements of the application, the addition of a surface tension modifier can be optional. A suitable surface tension modifier should be used in quantities that reduce the composition’s surface tension by at least 10 mN/m. Preferably, it should be 15 mN/m and 20 mN/m. A composition that does not contain a surface tension modifier is one with the same ingredients and proportions.
A viscosity modifier is an agent that reduces viscosity in an aqueous mixture, including NFC. When added to the composition at 0.1% of the aqueous mixture, preferred viscosity modifiers reduce the room temperature viscosity by at least 750cP.
“Cellulosic Sheet and Papermaking Components” and related Terminology
“The term ‘cellulosic’,?cellulosic sheets?? All products containing papermaking fiber with cellulose as a major component are included in these and other similar products. ?Papermaking fibers? ?Papermaking fibers include virgin pulps, recycled (secondary), cellulosic fibres, or fiber mixtures comprising cellulosic fibrils. Nonwood fibers are suitable for making the webs according to this invention. These include cotton fibers or their derivatives, abaca and sabai, flax and esparto grass; straw and jute hemp; and wood fibers such a those from deciduous or coniferous trees. This includes softwood fibers like northern and southern softwood Kraft fibres; hardwood fibers such eucalyptus and maple; birch and aspen. The papermaking fibers that are used in connection to the invention are usually naturally occurring pulp-derived fibres, rather than reconstituted fibers like lyocell and rayon. These fibers are freed from their source material using any of the many pulping processes known to those who are skilled in the art, such as sulfite or polysulfide, soy pulping, and the like. If desired, the pulp can be bleached using chemical methods, such as oxygen, chlorine dioxide, and alkaline peroxide. The present invention can include a mixture of conventional fibers, whether derived from virgin pulp or recycled sources, and high coarseness lignin rich tubular fibers such as bleached chemically thermomechanical pulp (BCTMP). Pulp-derived fibers thus also include high yield fibers such as BCTMP as well as thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP) and alkaline peroxide mechanical pulp (APMP). ?Furnishes? “Furnishes” and similar terms refer to aqueous compositions that include papermaking fibers, optionally high strength resins, debonders, and other such compounds for making absorbent basesheets.
“Debonder compositions contain surfactants and are widely employed in the paper industry. U.S. Patent. No. No. 7,736,464 to Kokko debonder composition comprising: (a) a surfactant component of quaternary ammonium; (b) a surfactant component that is nonionic. In many cases, these compositions include a quaternary ammonium surfactant component comprising a surfactant compound selected from the group consisting of a dialkyldimethyl-ammonium salt of the formula:”
“a bis-dialkylamidoammonium salt of the formula:”
“a dialkylmethylimidazolinium salt of the formula:”
“wherein R can be different and R means a hydrocarbon chain with a length of about twelve to twenty-two carbons. Each R could be saturated or unsaturated. The nonionic surfactant typically includes the reaction product from a fatty oil or fatty alcohol with an ethylene oxide, such as a polyethylene glycol derster of a fat acid (PEG diols and PEG diesters). A preferred composition that is used in connection to the invention is 30 wt.% of imidazolinium, (Im+), quats in a 1:1 mix of PEG400-mono & dioleates.
“Quaternary ammonium surfactant components most preferably include an imidazolinium sodium salt. U.S. Patent. No. 5,622,597 to Callen et al. ; U.S. Pat. No. No. No. No. No. Phan et. al. 5,698,076 ; U.S. Pat. No. 5,730,839 to Wendt et al. ; U.S. Pat. No. Jenny et. al. 5,753,079 ; U.S. Pat. No. No. No. Phan et. al. 5,279/767 U.S. Pat. No. No. 5,240,562 in Phan et. al. The absorbent sheet’s debonder is applied on a dry basis in pounds of debonder/ton papermaking fiber.
“In 2 to 3 ply products tail-sealed according to the invention, at minimum one of a first or second absorbent cellulosic basissheets may be treated in an amount from 1 lb to 16 lbs debonder mixture per ton cellulosic fiber used for making the basesheet. More often, at least one of two absorbent cellulosic basessheets or the second cellulosic basissheets are treated with debonder mixture in an amount of between 2 lbs and 10 lbs per ton papermaking fiber to make the basesheet. You may also use intermediate amounts.
The debonder can be applied to the sheet using any suitable method, such as spraying or adding it to the aqueous furnish of the papermaking machine that produces the sheet. If a multilayer headbox is being used to produce plies with multiple layers, the treatment levels for debonder will apply to all layers of the sheet. If one layer is free from any added debonder, other than residual debonder in water, and the sheet’s second layer is treated with 4 lbs of papermaking fiber/ton, the basesheet will be considered to have been treated at a level 4 lbs/ton.
Kraft softwood fiber is a low-yield fiber that is made from coniferous material. It includes Kraft (sulfate), northern and southern Kraft fiber, Douglas Fir Kraft fiber and so on. Kraft softwood fibers have a lignin percentage of less than 5 per cent by weight and a length-weighted average fiber width of more than 2 mm. They also have an arithmetical average fiber length greater than 0.6mm.
Kraft hardwood fiber is made from hardwood sources (eucalyptus) and has a lignin percentage of less than 5% by weight. Kraft hardwood fibers are typically shorter than softwood fibers. They have a weighted average fiber length less than 1mm, and an arithmetic mean length less than 0.5mm or 0.4mm.
“Recycle fiber can be added to papermaking furnish in any quantity. Any suitable recycle fiber can be used. However, it is preferable to use recycled fiber with a relatively low level of ground wood. This could be for example, recycled fiber with less than 15% or 10% by weight lignin, depending on the application and furnish mixture. In many cases, recycled fiber is 80% hardwood fiber.
“?Basesheet? A unitary cellulosic paper sheet that is produced by a paper machine. Basesheets can be layered, but they are not easily delaminated. A “ply” is a combination of two or more basesheets. A?ply? refers to a basesheet that is incorporated into a multiply product.
“Unless otherwise stated, the weight of a 3000ft2 product ream is referred to as the?basis weight?. BWT, weight, weight, and so forth. For example, consistency refers to the percent solids in a nascent internet. It is calculated on a bone dry basis. ?Air dry? Or simply?dry? It is a condition that includes residual moisture. Conventionally, pulp can retain about 10 percent of its moisture and paper up to 6 percent. A web with 50 percent water and 50% bone dry pulp has a consistency rate of 50 percent.
“The invention’s products are made from a cellulosic fiber basissheet and have an absorbency value or SAT value, as well as tensiles suitable for towel and tissue products. SAT values of about 3 g/g are common in most cases. U.S. Pat. No. 8,778,138.”
“?CWP? “?CWP?” refers to absorbent products that are made using a traditional wet-press process. This is where a furnish is wet-pressed to a drying cylindrical with a papermaking feel and then the web is removed from the cylinder. U.S. Pat. No. 7,951,266, FIG. 7 thereof.”
“?Structured? Basesheet is a product that has been wet creped (fabric-creped) from a cylindrical before final drying. U.S. Pat. Nos. 7,850,823, 7,585,388 and 7,585,389 respectively. 7,662,257
“?TAD? Refers to absorbent products that have been dried through air. The following patents disclose through-air dried, creped products: U.S. Pat. No. No. ; U.S. Pat. No. 4,102,737 to Morton; U.S. Patent. No. No. 4,529480 to Trokhan. These patents describe, very generally speaking, the following: forming a web on foraminous supports, thermally pre-drying it, applying the web with a Yankee dryer with an in part defined nip by an impression fabric and creping the product using the Yankee dryer.
The furnish, basis weight, strength, and papermaking technology can all affect the absorbent properties of a product. The selection of bonding agents characteristics will be affected by the sheet absorbency and converting technologies for a particular product. TAD sheets are less consolidated than CWP sheets, so they may have a lower rate of wicking. Tissue sheets and towels often contain more softwood than towel sheets. This can affect the distribution of the web’s pore sizes. You should be aware that the bonding agent formula that works best for one product might not work for another.
“A towel product is usually characterized by more than 50% of its fiber content (based on weight) being made from softwood fiber.”
“A tissue product is usually characterized by having more than 50% (based on fiber content), hardwood fiber.”
“The following examples show how tail-seal adhesives with the features listed in Tables 1 through 3B were tested for their effectiveness with TAD, CWP and structured sheet products. The adhesives are usually prepared by adding NFC and another modifier to conventional adhesives or combining NFC and viscosity modifiers, as described below. ?PolymerGC Glue? The term “PolymerGC Glue” is used throughout the specification and in Tables 1 and 2A. It refers to glue material primarily made up of glycols like PEG and water-soluble cellulose derivatives, as described in U.S. Pat. No. No. Weight percent refers only to the weight percent solids for glue components other than water. In the tables describing PolymerGC Glue compositions, the Glycol:Cellulose derivatives weight ratios are shown. To make the invention tail-seal adhesive, the PolymerGC Glue components have been blended with NFC. These components may be the only component of the adhesives. Here are additional formulations, including those that use PVOH glues, which could be suitable for tail seal adhesives.
“TABLE 1\nRepresentative PolymerGC Glue based NFC Containing Tail-Seal\nCompositions\nComponent General Typical\nPolymerGC Glue (wt %) 1.5-7?? 2-6\nNFC (wt %) 0.025-0.5? 0.035-0.35\nPolymerGC Glue:NFC ?5-125 ?10-120\nWeight Ratio\nGlycol:CellD Weight ?2-10 3-7\nRatio\nWater (wt %) 90-99 94-98\nOther additives balance balance”
“TABLE 2\nRepresentative PolymerGC Glue, Viscosity Modifier Based NFC\nTail-Sealing Compositions\nComponent General Typical\nPolymerGC Glue (wt %) 1-5 2-4\nViscosity Modifier (wt %) 0.25-3?? 0.4-2\nNFC (wt %) 0.25-1?? 0.25-1???? 0.4-2nNFC (wt.%) 0.25-1?
“TABLE 3\nRepresentative Viscosity Modifier Based Tail-Seal Compositions\nComponent General Typical\nViscosity Modifier (wt 0.05-2?? 0.075-1.5\n%)\nNFC (wt %) 0.05-0.75 0.075-0.65\nNFC:Viscosity Modifier ? ?2.5%-1000% ? ?7%-500%\nWeight Ratio (%)\nWater (wt %) 95-99 ? ?97-98.5nOther additives balance balance
“TABLE 3A\nRepresentative PolymerGC Glue/NFC/Viscosity Modifier\nCompositions with NFC:Viscosity Modifier Ratios of