Wet spread paper and paperboard products with high wet strength and methods of making same

Abstract

A method of making paper and paperboard products comprising absorbent structures is disclosed. The method comprises mixing an ultra-high molecular weight ("UHMW") glyoxalated polyethylene amide ("GPVM") adduct and a high molecular weight ("HMW") anionic polyacrylamide ("APAM") with ingredients in the raw material preparation process of the wet laying papermaking method. High wet strength paper and paperboard products are also disclosed.

Description

[0001] Related Applications

[0002] This application claims priority to and the benefits of U.S. Provisional Patent Application No. 63 / 352,903 filed on June 16, 2022, U.S. Provisional Patent Application No. 63 / 353,243 filed on June 17, 2022, and U.S. Provisional Patent Application No. 63 / 354,512 filed on June 22, 2023, the contents of all applications being incorporated herein by reference in their entirety. Technical Field

[0003] The present invention relates to a method for producing wet laid paper and paperboard products (e.g., disposable absorbent structures) having high wet strength without using polyaminoamide-epihalohydrin (PAE) or polyamine-epichlorohydrin resins and to wet laid paper and paperboard products having very low dosages of PAE resins. Background Art

[0004] Many paper and paperboard products, such as disposable paper towels, napkins, and facial tissues, are absorbent structures that need to remain strong when wet. For example, paper towels need to maintain their strength while absorbing 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. Disposable paper towels that can perform these demanding tasks while being soft have a competitive advantage because the towel can be multi-purpose and can be used as a napkin and a facial tissue. The same is true for napkins or facial tissues, which can become multi-purpose products if the right combination of quality attributes can be achieved, with strength when wet, absorbency, and softness being the key attributes.

[0005] Wet strength is useful in a wide variety of paper and paperboard products that can be described by grades, including tissue, paper towels, packaging, publications, and laminate grades. Paper and paperboard products that benefit from increased wet strength are useful in a wide variety of applications, some examples of which are facial tissue, kitchen paper towels, milk and juice cartons, produce boxes, paper bags, coffee filters, tea bags, and recycled linerboard for corrugated boxes. In all of these paper and paperboard products, whether absorbed intentionally or unintentionally, increased wet strength can be beneficial for intended use during exposure to liquids, including during normal handling (e.g., drying with paper towels, using tea bags, etc.) or in incidental contact (e.g., exposure of packaging to ambient moisture).

[0006] There are many industrial methods or technologies for producing paper and paperboard products containing absorbent structures. Generally speaking, these technologies are implemented using paper machines. Paper machines vary greatly in design, but generally include parts for forming, consolidating and drying paper sheets from paper stock. The specific components and forms of the machines also vary, and include different types, such as cylinder paper machines, fourdrinier paper machines, twin-wire formers, multi-layer formers, etc., and their variations. Examples of some such machines and the specific functions of their components are described in U.S. Patents Nos. 7,169,262 and 11,365,515, the contents of which are incorporated herein by reference in their entirety, and in other references herein. The technology of using water to form a cellulose (or other natural or synthetic fiber type) web in a paper sheet that constitutes a paper and paperboard product (e.g., a structured tissue or a scouring towel) is called water-laid technology. These include through-air drying (TAD), uncreped through-air drying (UCTAD), conventional wet crepe (CWC), conventional dry crepe (CDC), ATMOS, NTT, QRT and ETAD processes. The technology of using air to form a web is called Air-Laid Technology. To enhance the strength and absorbency of these tissues and wipes, more than one web (or layer) may be laminated together using strictly mechanical methods or preferably mechanical methods using adhesives.

[0007] Absorbent structures can be produced using either water-laid technology or air-laid technology. Water-laid technology of conventional dry creping and conventional wet creping is the primary method for making these structures. These methods involve forming a nascent web in a forming structure, transferring the web to a dewatering felt, pressurizing it on the dewatering felt to remove water, and adhering the web to a Yankee Dryer. The web is then dried, creped, and wound up from the Yankee dryer. When the solids content is less than 90%, the process is called conventional wet creping. When the solids content is greater than 90%, the process is called conventional dry creping. These methods can be further understood by referring to Yankee Dryer and Drying, TAPPI Press, pp. 215-219, the contents of which are incorporated herein by reference in their entirety. These methods are well understood and are easy to operate at high speeds and production rates. Energy consumption per metric ton is low because nearly half of the water removed from the web is removed by drainage and mechanical pressing. Unfortunately, paper pressing also compacts the web, which reduces web thickness and ultimate absorbency.

[0008] Through-air drying (TAD) and uncreped through-air drying (UCTAD) processes are wet-laid technologies that avoid compaction of the web during drying, thereby producing absorbent structures with superior caliper and absorbency compared to structures of similar basis weight and material input produced using CWC or CDC processes. Patents describing creped through-air dried products include U.S. Patents Nos. 3,994,771, 4,102,737, 4,191,609, 4,529,480, and 5,510,002, while U.S. Patent No. 5,607,551 describes an uncreped through-air dried product. The contents of these patents are incorporated herein by reference in their entirety.

[0009] The remaining wet-laying processes, referred to as ATMOS, ETAD, NTT, STT, and QRT, can also be used to produce absorbent structures. Each process / method utilizes some pressure to dehydrate a web or a portion of a web, thereby producing an absorbent structure having an absorbent capacity related to the amount of pressure used when all other variables are the same. The ATMOS process and products are recorded in application numbers 7,744,726, 6,821,391, 7,387,706, 7,351,307, 7,951,269, 8,118,979, 8,440,055, 7,951,269 or 8,118,979, 8,440,055, 8,196,314, 8,402,673, 8,435,384, ETAD methods and products are disclosed in U.S. Pat. Nos. 7,339,378, 7,442,278, and 7,494,563, the contents of which are incorporated herein by reference in their entirety. The NTT method and product are disclosed in international patent application WO 2009 / 061079 A1 and U.S. patent applications with publication numbers US2011 / 0180223 A1 and US 2010 / 0065234 A1, the contents of which are incorporated herein by reference in their entirety. The QRT method is disclosed in U.S. patent application publication number 2008 / 0156450 A1 and U.S. patent application number 7,811,418, the contents of which are incorporated herein by reference in their entirety. The STT method is disclosed in U.S. patent application number 7,887,673, the contents of which are incorporated herein by reference in their entirety.

[0010] All the aforementioned wet laying techniques can produce single or multi-layer webs of absorbent structures. To form multi-layer webs, a double or triple layer headbox is used, wherein each layer of the headbox can receive a different furnish flow.

[0011] In order to impart wet strength to absorbent structures in a wet-laying process, a cationic strength component is typically added to the furnish during stock preparation. The cationic strength component may comprise any polyethyleneimine, ethylenediamine-capped polyethyleneimine, polyaminoamide-epihalohydrin (preferably epichlorohydrin), polyamine-epichlorohydrin, polyamide, polyvinylamine, or polyvinylamide wet strength resin. Useful cationic thermosetting polyaminoamide-epihalohydrin ("PAE") and polyamine-epichlorohydrin resins are described 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、3,3 and 5,714,552, the contents of which are incorporated herein by reference in their entirety. Cationic thermoset PAE resins are the most widely used wet strength resins in wet-laid absorbent structures such as paper towels, napkins, and facial tissues due to their chemical ability to produce large amounts of wet strength at affordable dosages. Unfortunately, during the synthesis of these PAE resins, unwanted byproducts are produced. These byproducts are known as adsorbable organic halogens (“AOX”) and include 1,3-dichloro-2-propanol (“DCP”) and 3-monochloro-1,2-propanediol (“CPD”).Known techniques for reducing the level of by-products in PAE resins are disclosed in U.S. Patent Nos. 5,470,742; 5,843,763; 5,871,616; 6,056,855; 6,057,420; 6,342,580; 6,554,961; 7,303,652; 7,175,740; 7,081,512; 7,932,349; 8,101,710; 5,516,885; 6,376,578; 6,429,267; and 9,719,212, the contents of which are incorporated herein by reference in their entirety. See also Crisp, Mark T. and Riehle, Richard J, Regulatory and sustainability initiatives lead to improved polyaminopolyamide-epichlorohydrin(PAE) wet-strength resins and paperproducts, TAPPI Journal, Vol. 17, No. 9, September 2018.

[0012] Technology has been developed to reduce AOX in PAE resins. Those skilled in the art are familiar with industry terminology, such as G1 for first generation PAEs with high AOX, G2 and G2.5 resins characterized by reduced AOX (e.g. Kymene TM 925NA wet strength resin and Kymene TM 217LX wet strength resin, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and G3 resin, for example, Kymene also available from Solenis TM GHP20 wet strength resin. G2 technology is taught in, for example, U.S. Patents Nos. 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. G2 resins typically have less than 1000 ppm by weight of DCP, and G3 resins typically contain less than 10 ppm by weight of DCP. Those skilled in the art also note that in attempts to reduce AOX, the efficiency and functionality of the resins are compromised. Higher application levels are required to achieve the goal of tensile strength.

[0013] As discussed, in order to impart wet strength to absorbent structures in a wet-laid process, cationic strength components can be added to the furnish during stock preparation. To impart cationic strength resin capacity, it is well known in the art to add water-soluble carboxyl-containing polymers to the furnish along with the cationic resin. Suitable carboxyl-containing polymers include carboxymethyl cellulose ("CMC"), as disclosed in U.S. Patents Nos. 3,058,873, 3,049,469, and 3,998,690, the contents of which are incorporated herein by reference in their entirety.

[0014] Absorbent structures are also made using the air-laid process. This process spreads cellulose or other natural or synthetic fibers in an air stream directed onto a moving conveyor. The fibers are gathered together to form a web that can be thermally bonded or sprayed with a resin and cured. The web is thicker, softer, more absorbent, and stronger than wet-laid. The web is known for having a textile-like surface and drape. The spunlaid process is a variation of the air-laid process that makes the web in a continuous process where plastic fibers (polyester or polypropylene) are spun (melted, extruded, and blown) and then directly spread into a web in a continuous process. This technology is popular because it can produce faster conveyor speeds and reduce costs.

[0015] To further enhance the strength of the absorbent structure, more than one layer of web (or layer) can be laminated together using strictly mechanical methods or preferably mechanical methods using adhesives. It is generally believed that a multilayer structure can have an absorbent capacity greater than the sum of the absorbent capacities of the individual layers. It is believed that this difference is caused by the interlayer storage space created by adding additional layers. When producing a multilayer absorbent structure, it is crucial that the layers are bonded together in a way that can be maintained when subjected to forces when the structure is used by consumers. Scrubbing tasks such as cleaning countertops, dishes, and windows will exert forces on the structure, which can cause the structure to break and tear. When the bonding between the layers fails, the layers move relative to each other, imparting friction at the layer interfaces. The friction at such layer interfaces can cause failure (breakage or tearing) of the structure, thereby reducing the overall effectiveness of the product in performing scrubbing and cleaning tasks.

[0016] There are many methods for joining or laminating multiple absorbent structure layers to produce a multi-layer absorbent structure. One common method is embossing. Embossing is generally performed by one of three methods: tip-to-tip (or knob-to-knob), nested, or rubber-to-steel ("DEKO") embossing. Tip-to-tip embossing is described in commonly assigned U.S. Pat. No. 3,414,459, while the nested embossing method is described in U.S. Pat. No. 3,556,907, the contents of which are incorporated herein by reference in their entirety. Rubber-to-steel DEKO embossing comprises a steel roller having an embossing tip opposite a pressure roller, sometimes referred to as a back embossing roller, having an elastomeric roller cover, wherein the two rollers are axially parallel and juxtaposed to form a nip, wherein the embossing tip of the embossing roller engages the elastomeric roller cover of the opposing roller, while a sheet of paper is passed through the rollers, and a second, unembossed sheet of paper is laminated to the embossed sheet of paper using a composite roller sandwiched between the steel embossing rollers. In an exemplary rubber-to-steel embossing process, a glue coating roller may be aligned in an axially parallel arrangement with a patterned embossing roller such that the glue coating roller is located upstream of the nip formed between the embossing and pressure rollers. The glue coating roller transfers adhesive to the embossed web on the embossing roller at the top of the embossing protrusions. The top of the embossing protrusions typically does not contact the periphery of the opposing idler roller at the nip formed therebetween, thus requiring the addition of a marrying roller to apply pressure for lamination.

[0017] Other attempts to laminate absorbent structural webs include bonding layers at the joining lines, where these lines include separate pressure point bonds. Point bonds are formed by using a thermoplastic low viscosity liquid, such as molten wax, paraffin, or hot melt adhesive, as described in U.S. Patent No. 4,770,920. Another method laminates a web of absorbent structure by thermally bonding the webs together using polypropylene meltblown fibers, as described in U.S. Patent No. 4,885,202. Other methods use meltblown adhesives applied to one side of an absorbent structural web in a spiral pattern, a stripe pattern, or a random pattern, and then the web is pressed against the side of a second absorbent structure, as described in U.S. Patent Nos. 3,911,173, 4,098,632, 4,949,688, 4,891,249, 4,996,091, and 5,143,776, the contents of which are incorporated herein by reference in their entirety.

[0018] Certain wet strength resins, such as some of the PAE resins described above, can also provide increased dry strength to paper products. This improvement in dry strength is becoming increasingly important, especially in light of the trend of paper manufacturers to use recycled fibers in paper and paperboard products to achieve cost reductions. This trend is driven by stricter legislative standards imposed on the paper industry and continued pressure from environmentally conscious paper users to increase the recyclability (e.g., repulpability) of paper products.

[0019] The process of repulping generally refers to any mechanical action that disperses dry pulp fibers into an aqueous pulp fiber suspension. Repulping conditions and commercially used equipment are discussed in "Handbook for Pulp & Paper Technologists, Second Edition" by GA Smook, Angus Wilde Publications, 1992, pages 194-195 and 211-212, which is incorporated herein by reference in its entirety. Repulping conditions depend largely on the type of paper used. For paper that does not contain wet strength resins, repulping can be easily performed in water at any temperature. The water may contain additional ingredients, such as wetting agents and pH buffers, and relatively high temperatures (e.g., 50° C., or higher) may be used.

[0020] There are a variety of methods available for determining the repulpability of paper and paperboard. For example, in the laboratory, repulpability is conveniently determined using a pulverizer as described in TAPPI Method T205 OM-88, (1988), which is incorporated herein by reference in its entirety. Some methods compare the wet strength of wet strengthened paper and paperboard after 2 hours of soaking and being completely saturated (fully wetted) with an aqueous medium, preferably water, to be substantially the same. For example, Tappi Method T456 defines saturation as the state when water completely penetrates and fills the fiber structure network to its maximum steady-state level under the conditions described in the method. As shown in Tappi Method T456, complete saturation of certain types of paper, particularly paperboard, can be significantly accelerated by immersion in (a) degassed distilled water, (b) normal distilled water, immersion under reduced pressure, or (c) by adding a wetting agent to the water. For paper and paperboard with sizing agents (e.g., liquid packaging board, carrier board, linerboard, and materials for produce boxes), complete wetting can usually be achieved by vacuum soaking, e.g., by 2-3 consecutive vacuum-to-atmospheric pressure cycles. For some paper grades, complete wetting can be achieved by using surfactants.

[0021] In view of the above, efforts to produce paper and paperboard having high levels of wet and dry strength and improved recyclability are well documented in the literature (e.g., U.S. Patent Nos. 11,015,287, 9,777,434, 9,212,453, 7,589,153, 6,103,861, 5,783,041, 5,674,362, 5,466,337, 5,427,652, the contents of which are incorporated herein by reference in their entirety). For example, some of the PAE wet strength resins described above are used to impart dry and wet strength to paper products.

[0022] Unfortunately, however, while high wet strength is desired in many applications, papers with this property are generally repulpable only under severe conditions. Relatedly, recycling of some paper products containing PAE wet strength resins is often difficult, in part due to limited repulpability.

[0023] In view of the foregoing, there is a continuing need for absorbent products having high wet strength, absorbency, and softness without producing any undesirable byproducts. There is also a need for methods and compositions that impart great wet and dry strength to paper products with improved repulpability. Summary of the invention

[0024] It is an object of the present invention to provide a method for producing a paper or paperboard product having high wet strength without or with very low dosages of PAE wet strength resins containing or generating AOX byproducts, and products made by the method. One embodiment provides a method for preparing a paper and paperboard structure having high wet strength, the paper and paperboard structure being made without polyaminoamide-epihalohydrin (PAE) or polyamine-epichlorohydrin resins, and using a lower dosage of PAE resins for the paper and paperboard structure while achieving the same target high wet strength level. Another embodiment provides a method for making a single-layer or multi-layer, cellulose-based, wet-laid, disposable, absorbent structure having high wet strength, absorbency, and softness without or with very low dosages of PAE wet strength resins containing or generating AOX byproducts.

[0025] A paper or paperboard product according to an exemplary embodiment of the present invention comprises: lignocellulose and / or cellulose fibers; dichloropropane at a concentration of less than 50 ppb; at least 0.05 wt% of an ultra-high molecular weight glyoxalated polyvinylamide (UHMWGPVM) adduct and a high molecular weight anionic polyacrylamide (HMWAPAM) complex; dichloropropane at a concentration of less than 300 ppb; 0 wt% to 0.09 wt% of polyaminoamide-epihalohydrin; and the product has a wet tensile strength of at least 10% of the dry tensile strength value.

[0026] In some exemplary embodiments, the paper or paperboard product comprises 0.25 wt. % to 1.5 wt. % of the UHMWGPVM adduct and HMWAPAM complex.

[0027] In some exemplary embodiments, the UHMW GPVM adduct and HMWAPAM complex comprises a HMWAPAM having a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons and / or a UHMW GPVM adduct having a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons. In certain embodiments, the UHMW GPVM adduct and HMWAPAM complex comprises HMWAPAM having a molar ratio of acrylic acid to acrylamide of 7:93 to 40:60.

[0028] In some exemplary embodiments, the paper or paperboard product is free of polyaminoamide-epihalohydrin as measured using the "adipic acid test."

[0029] In some exemplary embodiments, the wet tensile strength of the paper or paperboard product is at least 20% of the dry tensile strength value of the product.

[0030] A paper or paperboard product according to an exemplary embodiment comprises: 80 to 99 wt% lignocellulose and / or cellulose fibers; 0.05 to 1.5 wt% UHMW GPVM adduct and HMWAPAM complex; and 0 to 0.5 wt% polyvinylamine.

[0031] In some exemplary embodiments, the product comprises 0.25 wt % to 1.5 wt % of the UHMW GPVM adduct and the HMWAPAM complex.

[0032] In some exemplary embodiments, the UHMW GPVM adduct and the HMWAPAM complex comprise a HMWAPAM having a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons and / or a UHMW GPVM having a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons. In certain embodiments, the UHMW GPVM adduct and the HMWAPAM complex comprise HMWAPAM having a molar ratio of acrylic acid to acrylamide of 7:93 to 40:60.

[0033] In some exemplary embodiments, the product exhibits at least 20% less repulping time than a similar PAE resin treated paper or paperboard product having a comparable level of defibration and substantially the same wet strength measured when fully wetted after a 2 hour soak. In some such embodiments, during repulping in water having a pH of about 9 or greater, the product exhibits at least 20% less repulping time than a similar PAE resin treated paper or paperboard product.

[0034] In some exemplary embodiments, the paper or paperboard product comprises 0.01 wt % to 0.5 wt % polyvinylamine.

[0035] A retail roll towel product according to an exemplary embodiment of the present invention comprises: two layers of cellulose paper sheets or webs having a transverse wet strength of 80 N / m to 200 N / m and a two-layer caliper of 600 μm to 1500 μm, wherein the retail roll towel product comprises 0 ppb to 550 ppb of 3-chloropropanediol and 0 wt % to 0.09 wt % of polyaminoamide-epihalohydrin.

[0036] In an exemplary embodiment, the wet strength of the tissue product in the transverse direction is 80 N / m to 150 N / m, the thickness of the two layers is 700 μm to 1300 μm, and the basis weight of the tissue product is 38 g / m 2 Up to 50g / m 2 , wherein the retail roll towel product contains 50 ppb to 550 ppb of 3-chloropropane and 0.01 wt % to 0.04 wt % of polyaminoamide-epihalohydrin. The tissue or paper towel product according to an exemplary embodiment of the present invention contains: 95 wt % to 99 wt % of cellulose fibers; 0.25 wt % to 1.5 wt % of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex.

[0037] The tissue or paper towel product according to an exemplary embodiment of the present invention comprises: 95 wt % to 99 wt % of cellulose fibers; 0.25 wt % to 1.5 wt % of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex; and 0.03 wt % to 0.5 wt % of polyvinyl amine.

[0038] The method for preparing a paper or paperboard product according to an exemplary embodiment of the present invention ("preparation method") includes: forming an aqueous raw material mixture comprising 80 wt% to 99 wt% of solid lignocellulose and / or cellulose fibers, 0.05 wt% to 1.5 wt% of solid ultra-high molecular weight glyoxalated polyvinylamide (UHMW GPVM) adduct and high molecular weight anionic polyacrylamide (HMWAPAM) complex, 0 wt% to 0.09 wt% of solid polyaminoamide-epihalohydrin, and 0 wt% to 0.5 wt% of solid polyvinylamine; and tableting and drying the aqueous raw material mixture to obtain a product.

[0039] In an exemplary embodiment of the preparation method, the aqueous feed mixture is formed without the addition of polyaminoamide-epihalohydrin, and the product is free of polyaminoamide-epihalohydrin as measured using the "adipic acid test."

[0040] In some exemplary embodiments, the UHMW GPVM adduct and HMWAPAM complex used in the preparation method include: HMWAPAM with a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons and / or a UHMW GPVM adduct with a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons. In certain embodiments, the UHMW GPVM adduct and HMWAPAM complex include HMWAPAM with a molar ratio of acrylic acid to acrylamide of 7:93 to 40:60.

[0041] In an exemplary embodiment of the preparation method, the aqueous feed mixture is formed from 0.03 wt % to 0.5 wt % solids of the polyvinylamine.

[0042] In an exemplary embodiment of the preparation method, the paper or paperboard product comprises dichloropropanol in a concentration of less than 50 ppb and 3-MCPD in a concentration of less than 300 ppb.

[0043] According to an exemplary embodiment of the present invention, a method for manufacturing an absorbent structure includes: forming a raw material mixture comprising cellulose fibers, high molecular weight anionic polyacrylamide, and ultra-high molecular weight glyoxalated polyacrylamide; and at least partially drying the raw material mixture using a wet laying method to form a web, wherein no polyaminoamide-epihalohydrin is added to the raw material mixture.

[0044] In an exemplary embodiment, the absorbent structure has a concentration of less than 50 ppb dichloropropanol and a concentration of less than 300 ppb 3-MCPD.

[0045] In an exemplary embodiment, the feedstock mixture further comprises an additive selected from the group consisting of lignin, laccase polymerized lignin, hemicellulose, polymerized hemicellulose, hemp hurd, pectin, hydroxyethyl cellulose, carboxymethyl cellulose, guar gum, soy protein, chitin, polyethylene amine, polyethylene imine, and combinations thereof.

[0046] An absorbent product according to an exemplary embodiment of the present invention comprises cellulose fibers, a concentration of less than 50 ppb of dichloropropane and a concentration of less than 300 ppb of 3-chloropropane, and a wet strength in the cross direction of 80 to 200 N / m, wherein the product is free of polyaminoamide-epihalohydrin as measured using the "adipic acid test".

[0047] In an exemplary embodiment, the absorbent product is a facial tissue, napkin, or paper towel that is air dried.

[0048] A tissue product according to an exemplary embodiment of the present invention comprises: a two-ply retail tissue creped by through-air drying, having a wet strength in the cross direction of 80 N / m to 150 N / m, a dry thickness of 700 μm to 1200 μm, 3-chloropropanediol measured in the paper constituting the product of 50 to 400 parts per billion, and dichloropropane measured in the paper of 30 to 200 parts per billion, wherein the polyvinyl amine is added to the wet-end of a paper machine used to make the tissue product.

[0049] The tissue product according to an exemplary embodiment of the present invention comprises: a two-ply retail tissue creped by air drying, having a wet strength in the cross direction of 80 N / m to 150 N / m; a dry thickness of 700 μm to 1200 μm; 3-chloropropanediol measured in the paper constituting the product of 50 ppb to 300 ppb; and dichloropropane measured in the paper of 5 to 50 parts per billion, wherein no PAE resin is added to the wet end of a paper machine used to manufacture the tissue product. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various exemplary embodiments of the present invention will be described in detail with reference to the following drawings, in which:

[0051] Figure 1 shows a pattern formed on an absorbent structure according to an exemplary embodiment of the present invention;

[0052] Figure 2 An exploded view of the equipment used during the wet scrub test;

[0053] Figure 3 The equipment used during the wet scrub test is shown;

[0054] Figure 4 An exploded view of the equipment used during the wet scrub test;

[0055] Figure 5 A top view of the textured polymer film used in the wet scrubbing test;

[0056] Figure 6 A flow chart showing a method of making an absorbent structure according to an exemplary embodiment of the present invention;

[0057] Figure 7 shows a chemical reaction for producing a novel wet strength agent according to an exemplary embodiment of the present invention;

[0058] Figure 8 shows a chemical reaction that produces a novel wet strength agent cross-linking with itself, for example, prior to forming a macrocomplex between GPAM and APAM, according to an exemplary embodiment of the present invention; and

[0059] Fig. 9Provides a table of DCP, CDP and PAE measurement results for commercially available tissue samples. DETAILED DESCRIPTION

[0060] Provided herein is a method for preparing a paper and paperboard structure having high wet strength, the paper and paperboard structure being made without a polyaminoamide-epihalohydrin (PAE) or polyamine-epichlorohydrin resin. The method can be used to prepare a paper and paperboard structure having a lower dosage of PAE resin while achieving the same targeted high wet strength level as a comparable structure made with PAE resin, and achieving improved repulpability and recyclability. Also provided is a paper and paperboard structure having a targeted high wet strength level using a lower dosage of PAE resin.

[0061] For the purposes described herein, the term "low dosage of PAE resin" or "very low dosage of PAE resin" refers to an absorbent structure (e.g., paper or paperboard product) that contains less than 2.5 kg of PAE per metric ton of thoroughly dry absorbent structure. In specific embodiments, the term "very low dosage of PAE resin" can be used to refer to a specific range or threshold value that depends on the type of absorbent structure. For example, the term can be used to refer to a tissue or paper towel product as an absorbent structure that contains less than 2.5 kg of PAE per metric ton of dry tissue or paper towel product. The term can also be used to refer to different types of paper or paperboard products as absorbent structures that contain less than 2 kg of PAE per metric ton of dry paper or paperboard product, or less than 1.5 kg, or less than 1 kg / ton of PAE per ton.

[0062] As used herein, the term "paper or paperboard product" (or, more simply, "paper or paperboard", or just "paper product" or "paper") will be understood by those skilled in the art to include various grades of paper and paperboard. Examples include any of the various grades of paper that benefit from enhanced wet strength and / or dry strength, such as boxboard, bags, cardboard, copy paper, boxboard, corrugated paper, folders, newsprint, paperboard, packaging board, printing and writing paper, tissue paper, paper towels, and publications. These paper grades can be composed of any typical pulp fiber, including groundwood, bleached or unbleached kraft paper, sulfate paper, semi-mechanical paper, mechanical paper, semi-chemical paper, and recycled paper. They may or may not contain inorganic fillers. In view of the description herein, further limitations on the scope of applicable paper products will be understood. If not otherwise explicitly stated, for the purposes of the present invention, as defined above, the terms "papermaking process" and "process for making paper" refer to the manufacture of paper and the manufacture of paperboard and / or cardboard.

[0063] In a specific embodiment, the paper or paperboard product is defined in terms of a particular absorbent structure, such as a tissue or towel product. However, in view of the description herein, it will be understood that the methods and products of the present invention are not limited thereto and encompass a wide variety of paper and paperboard products.

[0064] As used herein, unless otherwise specified, the terms "absorbent structure" and "absorbent product" are used interchangeably.

[0065] In an exemplary embodiment, a paper or paperboard product (e.g., an absorbent product) is manufactured in the absence of PAE and therefore, when analyzed using the adipic acid and / or glutaric acid specific method, exhibits the absence of PAE (to the detectable limit of the measurement method), and in addition, the product contains DCP and CPD at levels so low that they are not detected above the environmental background.

[0066] The method for making paper using the composition of the present invention, further described below, is exemplified by the following steps: (a) providing an aqueous stock mixture (i.e., a pulp suspension); (b) adding the strength composition to the aqueous stock mixture; and (c) sheeting and drying the aqueous stock mixture produced in (b) to obtain a paper or paperboard product.

[0067] The raw material mixture can be a papermaking furnish or other aqueous pulp suspension, and can be a mixture of lignocellulosic fibers, cellulose fibers, and fillers. The filler can be an inorganic filler (e.g., calcium carbonate or clay), or an organic filler. Regenerated fiber is generally a mixture of fiber type and filler type. Generally speaking, it should be understood that the raw material mixture in (a) is generally prepared with pulp, which generally comprises cellulose fibers. Typically, these fibers comprise cellulose and / or lignocellulosic fibers, and can be prepared by materials comprising wood-based pulp from groundwood to chemically bleached wood or non-wood-based pulp or a combination of pulps. In addition, pulp can be obtained in whole or in part from recycled paper and paper products. Pulp can comprise some synthetic pulps. Pulp can be some combinations of pulp types (e.g., hardwood and softwood, or certain types of wood, such as eucalyptus). Pulp can be groundwood, mechanical pulp, chemically or thermally treated pulp, kraft pulp, sulfite pulp, or any other common pulp used in synthetic pulp or papermaking industry.

[0068] The raw material mixture of step (a) of the method is obtained by means well known in the art, such as known mechanical, chemical and semi-chemical pulping methods. Typically, after the mechanical abrasion and / or chemical pulping steps, the pulp is washed to remove residual pulping chemicals and dissolved wood components. Both bleached and unbleached pulp fibers can be used in the method of the present invention. Recycled pulp fibers are also suitable for use.

[0069] In some aspects of the present method, the strength composition can be used to treat all types of cellulose fibers, such as lignocellulose fibers, including bleached, unbleached virgin fibers, mechanical fibers and OCC regenerated fibers. In some aspects of the present method, the strength composition can be used to treat a mixture of bleached fibers, unbleached virgin fibers and regenerated fibers at a certain fiber mixing ratio. In other aspects, the strength composition of the present method helps to provide improved dry strength properties for the regenerated linerboard manufactured in papermaking. The strength composition can be effectively used with low-quality regenerated fibers from Asia (e.g., EOCC (European OCC), and better quality AOCC (American OCC) and unbleached kraft fiber (UBSK)). The degree of improvement in specific strength performance varies with fiber type and processing conditions.

[0070] In some aspects of the present method, the strength composition can be used to treat a pulp slurry or as a pulp and filler slurry. The slurry can be any slurry known in the art, for example based on virgin pulp, deinked pulp (DIP), unbleached kraft pulp (UBK), mechanical pulp such as thermomechanical pulp (TMP), semi-chemical mechanical pulp such as neutral sulfite semi-chemical (NSSC), old corrugated container (OCC), recycled newspaper, recycled tissue or other fiber sources. The pulp can be present in the slurry in any amount known in the art.

[0071] For the purposes of this specification, the cellulose starting material for making paper, paperboard and / or cardboard may be derived from recycled (waste) paper. Such material may be referred to as "recycled material", whereas fresh starting material is referred to as "virgin material". A blend of virgin material and recycled material may also be used as starting material for the papermaking process (i.e., in a stock mixture), which is referred to herein as a "blend material". In addition, the cellulose starting material may also be "brokes" or "coated brokes", which, for the purposes of this specification, shall be covered by the term "recycled material".

[0072] In recycling operations, it is currently preferred to separate paperboard with high wet strength from paperboard with low wet strength (usually not treated with PAE resins). For optimal recyclability and fiber regeneration, the repulping conditions for paper and paperboard with high wet strength are preferably without adding additional chemicals to the pulper so that a mixture of paper and paperboard with high wet strength and low wet strength can be repulped together. Preferably, the repulpability is sufficient to allow certification by various organizations. For example, the Fiber Box Association (FBA) allows boxes to be certified and marked as renewable for easy identification when the processed material has passed a testing protocol to ensure acceptability by old corrugated box (OCC) recyclers.

[0073] The composition of the present process may be introduced into the pulper during the pulping stage, or contacted in any stock storage tank, high consistency tank or other storage tank.

[0074] A range of cellulose fiber types, lignocellulose fiber types and filler types can be used in the stock mixture. The amount of fiber is generally in the range of 70% to 99% by weight. For example, the paper or paperboard product prepared according to an embodiment of the present invention can comprise 70% to 99% by weight, 80% to 99% by weight, 85% to 99% by weight or 90% to 99% by weight of lignocellulose fibers. In the stock mixture, these amounts can refer to the weight percentage of solids. Alternatively, it will be appreciated by those skilled in the art that additional weight of solids can be used in the stock mixture to prepare the product with the fiber loading in the above-mentioned scope.

[0075] In a specific embodiment, the raw material mixture as the aqueous suspension of cellulose fibers comprises both virgin fibers and regenerated fibers. In some embodiments, the aqueous suspension comprises at least 30% virgin fibers, such as at least 70%, or at least 90%, or at least 95%, or at least 99% virgin fibers (w / w), based on the total weight of cellulose fibers in the suspension. In some such embodiments, the aqueous suspension is unbleached kraft (UBK) virgin furnish.

[0076] In some embodiments, the raw material mixture as the aqueous suspension of cellulose fiber comprises regenerated fiber.The amount of regenerated fiber can change, and can be used to supplement virgin fiber or as the main fiber source in aqueous suspension.Therefore, based on the gross weight of cellulose fiber in suspension, aqueous suspension can comprise at least 1% or at least 5% or at least 10% or at least 20% or at least 30% or at least 50% or at least 75% amount of regenerated fiber (w / w).It is to be understood that regenerated fiber may be derived from mixed paper grades, old corrugated board (OCC) etc.

[0077] In some embodiments, the strength composition can be used to process difficult furnishes, i.e., furnishes with relatively high contents of lignans and possibly other dissolved and / or suspended colloidal anionic materials. For example, the strength composition can be used with high kappa furnishes, i.e., furnishes of pulp having a kappa number of at least 20, or at least 25, or at least 30, or at least 32, or at least 35, or at least 40.

[0078] The term "kappa" used herein in the context of strength compositions and methods of use thereof should be understood according to the conventional meaning of the industry standard kappa number. Therefore, it should be understood that the kappa number is used as a key test method for determining the residual lignin content / level in a finished pulp or in-process pulp sample. In this way, the kappa number can be used as a measure of the integrity of a given pulping method, and can be used to characterize and / or distinguish the type of furnish based on the relative lignin content. The type of pulp is not particularly limited in terms of kappa number determination, and generally accepted standards are applicable to determining the kappa number of various pulps, including chemical, semi-chemical, unbleached, semi-bleached, and bleached types. For example, the kappa number of a given furnish can be determined by using a strong oxidant (e.g., potassium permanganate), which reacts with lignin and a small amount of certain other organic impurities remaining in the pulp at various process stages. The kappa number of a particular sample can be determined manually (e.g., by laboratory reaction and analysis), or by using an automated instrument suitable for measuring the kappa number. It should be understood that it may be necessary to verify a given procedure and / or instrument based on the details of a given standard in order to determine the consistency of the results with the standard itself. An example of a kappa number standard includes test method TAPPI / ANSI T 236 om-13 (November 2013), provided by the Technical Association of the Pulp & Paper Industry Inc. (TAPPI) and approved by the American National Standards Institute (ANSI). As described, the TAPPI / ANSI T 236 om-13 standard is intended for laboratory testing of pulp. However, it is recognized that the kappa number is widely used as an in-process test in pulp and paper mills, with modifications in some cases.

[0079] Typically, Kappa numbers are reported as values ​​from 1 to 100. However, values ​​above 100 may be determined, although it should be understood that Kappa numbers above 100 may reduce the precision of a given test. Section 16 of the TAPPI / ANSI T 236om-13 standard sets forth information regarding the unintended or unexpected effects that certain deviations from the standard may have on data accuracy, precision, or both.

[0080] In some cases, the Kappa number can be used to quantify, or at least approximate, the lignin content of a particular pulp sample. For example, for pulps with a total yield of less than 70%, there is a nearly linear relationship between the Kappa number and the Klason lignin and chlorine values, so that the Kappa number determined according to the TAPPI / ANSI T 236om-13 standard can be used to approximate the percentage of Klason lignin in the sample according to the equation, lignin level (%) = Kappa number × 0.13. However, it should be understood that there is no general and clear relationship between the Kappa number and the exact content of lignin or other organic impurities between pulps. On the contrary, any such relationship may vary depending on the wood species, pulping method, and delignification procedure used to obtain the specific pulp prepared. Therefore, when the Kappa number is used to determine the exact value of the amount of lignin present in a specific batch (such as those suitable for use in the present embodiment), a more accurate relationship can be established by testing the pulp therein according to methods and procedures known in the art.

[0081] In certain embodiments, the strength composition is used with a furnish of pulp having a Kappa number of 1 to 30, e.g., 1 to 25, or 1 to 20, or 1 to 15. One skilled in the art will select a particular furnish depending on the particular paper or paperboard product being produced, the process conditions being employed, etc.

[0082] According to an exemplary embodiment, the present method involves the use of a strength composition as described above. More specifically, the strength composition comprises a glyoxalated polyamide component and an anionic polyacrylamide component, which will be described in turn below. The compounds selected as the glyoxalated polyamide component and the anionic polyacrylamide component can constitute all or part of the strength composition. In addition, it can be understood from the specific components described herein that the two components of the strength composition can be supplied separately or together (e.g., combined), and are also used in combination in the method herein, or as a premixed combination, or as a discrete component added to the raw material mixture together or separately.

[0083] The glyoxalated polyamide component of the strength composition comprises an ultra-high molecular weight ("UHMW") glyoxalated polyacrylamide ("GPVM") adduct, and may comprise a high molecular weight ("HMW") and / or high cationic charge glyoxalated polyacrylamide ("GPAM") copolymer, or a combination thereof. One skilled in the art will appreciate that the terms "glyoxalated polyacrylamide adduct" and "GPVM" used in this manner may encompass GPAM, as the industrial usage range of the terms overlaps depending on the specific components of the polymer being prepared. Therefore, for the purposes of the present invention, the term "GPVM adduct" should be broadly understood to encompass glyoxalated polyamides prepared using acrylamide-based and / or vinylamide-based prepolymers, which will be described in further detail below. When it is necessary to distinguish between the two, specific references to specific polyacrylamide or polyacrylamide will be used. For example, the term "GPAM / APAM" complex used below refers to a specific embodiment in which a GPAM-based GPVM adduct is used in the strength composition.

[0084] GPVM adducts can be prepared or obtained. Methods for preparing GPVM adducts are known in the art. For example, methods for preparing UHMW GPVM are described in U.S. Patents Nos. 7,875,676 B2 and 9,879,381 B2, the contents of which are incorporated herein by reference in their entirety. These patents also characterize the polymers and prepolymers involved, including their molecular weights. Methods for preparing HMW and / or high cationic charge GPAM copolymers are described in U.S. Patent No. 9,644,320, the contents of which are incorporated herein by reference in their entirety.

[0085] In some embodiments, the weight average molecular weight of the UHMW GPVM adduct is greater than 2,000,000 Daltons and less than 50,000,000 Daltons, such as about 5,000,000 Daltons to about 40,000,000 Daltons, about 8,000,000 Daltons to about 25,000,000 Daltons, about 10,000,000 Daltons to about 20,000,000 Daltons, or about 12,000,000 Daltons to about 18,000,000 Daltons. The Mw of the UHMW GPVM adduct can be determined using the batch mode MALS method described below.

[0086] In some embodiments, the UHMW GPVM has a radius of gyration (Rg) of at least about 100 nm. In some embodiments, the Rg of the UHMW GPVM is at least about 20 nm, such as at least about 140 nm, or at least about 150 nm, or at least about 160 nm, or at least about 170 nm.

[0087] The UHMW GPVM typically has a charge density of about 0.2 mEq. / g to about 3 mEq. / g at pH 7. In some embodiments, the UHMW GPVM has a charge density of about 1 mEq. / g to about 3 mEq. / g at pH 7.

[0088] The anionic polyacrylamide component comprises high molecular weight ("HMW") anionic polyacrylamide ("APAM"). HMWAPAM is defined as having a molecular weight greater than 500,000 Daltons and can be an inverse emulsion product or a solution product, preferably a solution product.

[0089] In some embodiments, the weight average molecular weight (Mw) of HMWAPAM is greater than 500,000 Daltons and less than about 2,000,000 Daltons, such as about 550,000 Daltons to about 1,500,000 Daltons, or about 550,000 Daltons to about 1,000,000 Daltons.The Mw of HMWAPAM can be determined using the following size exclusion chromatography (SEC) method.

[0090] In some embodiments, the HMWAPAM has a molar ratio of acrylic acid to acrylamide greater than 7:93 and less than 40:60, preferably greater than 12:88 and less than 35:65, preferably greater than 15:85 and less than 30:70. In some embodiments, the strength additive comprises HMWAPAM having a molar ratio of acrylic acid to acrylamide of 7:93 to 40:60. In certain embodiments, the strength additive comprises HMWAPAM having a molar ratio of acrylic acid to acrylamide of 12:88 to 35:65.

[0091] The invention also features polymers and prepolymers comprising this molecular weight. The standard viscosity of the high molecular weight anionic polyacrylamide (using a Brookfield viscometer with a UL adapter at 60 rpm, measuring a 0.1 wt % polymer solution in 1M NaCl at 25°C) can be less than 1.5 or less than 1.6 or less than 1.7 or less than 1.8.

[0092] By using a chemical composition of two or three or more individual components (referred to herein as wet strength agents), the strength composition provides a wet tensile strength of at least 10%, such as 15% or 20% or 25% or 30% of the dry tensile strength value of the paper or paperboard product, the dry tensile strength value being measured in the cross or longitudinal direction of the paper or paperboard product.

[0093] In some embodiments, the present method uses UHMW GPVM with a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons and HMWAPAM with a Mw greater than 500,000 Daltons to 2,000,000 Daltons. In certain embodiments, the present method uses UHMW GPVM with a Mw of 10,000,000 Daltons to about 20,000,000 Daltons and HMWAPAM with a Mw of 550,000 Daltons to 1,500,000 Daltons.

[0094] In embodiments, polyvinylamine (PVAM) chemistries, through different components than those described above for UHMW GPVM adducts and HMWAPAM, can also greatly improve the effectiveness of the wet strength system without adding PAE or chlorinated organics to the mix.

[0095] In some embodiments, PAE resins and / or polyvinyl amines are included in the strength composition or otherwise added to the stock mixture.

[0096] The strength composition of the present method can be used in combination with other papermaking performance additives to improve paper product properties, such as cationic, anionic, zwitterionic, nonionic synthetic compounds and natural polymers. Examples of compounds suitable for use with the compositions of the present method include, but are not limited to, dry strength papermaking additives such as starch, starch derivatives, polyacrylamide derivatives, guar gum, poly(vinylamine), contaminant control anti-adherents or fixed anti-adherents such as nonionic or anionic anti-adherents, hydrophobically terminated poly(ethylene glycol), poly(vinyl alcohol-vinyl acetate), whey protein, soy protein, hydrophobic and hydrophilic block copolymers, hydrophobically modified hydroxyethyl cellulose, wet strength papermaking additives including, but not limited to, polyethyleneimine, urea formaldehyde resins, poly(amide-amine) reacted with epichlorohydrin, starch aldehyde, glyoxalated poly(acrylamide); flocculants for water treatment; coagulants for water treatment; filter aids for papermaking; retention aids for papermaking; sizing agents for paper products; adhesives; debonding agents; softeners; creping adhesives; plasticizers for optimizing resin properties; and modifiers for optimizing resin properties. The individual components of any of the above combinations may be applied together or sequentially in papermaking. Furthermore, the individual components listed above can be combined or blended together prior to use to produce a stable formulation, or they can be combined on-site at the paper mill prior to use.

[0097] In some embodiments, the strength composition is used in combination with one or more conventional papermaking aids. Examples include sizing agents, retention aids based on synthetic polymers and dual systems, filter aids, optical brighteners, defoamers, biocides, and paper dyes. Specific examples of such aids are known in the art and are included in those listed in the references incorporated herein. For example, useful sizing agents include alkyl ketene dimers (AKD), olefin succinic anhydrides (ASA), and rosin size, etc. These conventional paper additives can be used in conventional amounts.

[0098] In some embodiments, the strength composition is particularly free of, or substantially free of, certain conventional paper additives. For example, while one of the benefits of this embodiment is the ability to reduce or eliminate the use of PAE, other strength additives, or certain components thereof, may also be reduced, minimized or eliminated by implementing the methods described herein. For example, in specific embodiments, the strength composition is not used with chemical compositions involving formaldehyde, such as urea formaldehyde (UF) or melamine formaldehyde (MF). In other embodiments, the specific amount of the UF or MF chemical composition used is limited below the regulatory threshold. In general, products prepared with the strength composition are substantially free of formaldehyde, that is, formaldehyde-based components are not used in the formation of the product. Those skilled in the art will appreciate that the products prepared and described herein may contain residual formaldehyde as an impurity or by-product and still be substantially free of formaldehyde as described above. Similarly, by using the strength composition, other chemical compositions may also be particularly avoided, or their use may be reduced. For example, the compositions, methods and / or products herein may be substantially free of isocyanate-based paper additives, styrene-butadiene or other latex-type paper additives, etc. In specific embodiments, the paper or paperboard product is substantially free of, or free of, latex additives.

[0099] In one aspect of the invention, the strength composition can be added to the pulp slurry in a minimum amount of about 0.05 wt % based on the dry weight of the pulp, can be about 0.1 wt % based on the dry weight of the pulp, can be about 0.2 wt % based on the dry weight of the pulp, can be about 3 wt % or more, and can be about 5 wt % or more.

[0100] In other aspects of the invention, the maximum amount of treated resin that can be added to the pulp slurry is about 3% by weight and can be about 1.5% by weight. The resin composition is usually added in the form of an aqueous solution. In addition to the resin, other materials commonly used for paper can also be added. These include, for example, sizing agents, pigments, alum, brighteners, dyes and dry strength agents, and the addition amounts are well known in the art.

[0101] In an exemplary embodiment, the method can further include adding various combinations of biopolymers to the furnish, including but not limited to lignin, polymerized lignin, lignin polymerized with laccase, hemicellulose, polymerized hemicellulose, guar gum, cationic guar gum, CMC, chitin, chitosan, microfibrillated cellulose ("MFC"), pectin, hemp fiber, and soy protein (or any protein source with increased MW or chemically linked to the biopolymers or pulp fibers listed above). The method can also involve using commercial pulp that has been coated with microfibrillated cellulose during or before the drying stage of the process of producing commercial pulp sheets. Microfibrillated cellulose and other biopolymers provide a large number of carboxyl and hydroxyl groups that can provide hydrogen bonding for the cellulose fibers and wet strength agents of the furnish to further improve the bonding network to provide improved wet and dry strength. With the improvement in dry strength, the refining of the cellulose fibers can be minimized to improve the softness of the product. In addition, due to the high surface area of ​​the MFC, the absorbency of the final absorbent structure is improved. After the wet strength agent is mixed with the furnish (which may include additives and MFC coated commercial pulp), the remaining steps of the wet laying process are completed to produce the absorbent structure.One of the unexpected aspects of the present invention is the use of conventional dry strength additives to enhance wet strength.

[0102] As described in further detail herein, the compositions of the present invention can provide greater than 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99% PAE replacement using 0.05 wt % to 1.5 wt % of ultra high molecular weight glyoxalated poly(ethylene amide) adduct and high molecular weight anionic poly(ethylene amide) complex while achieving the same targeted high wet strength levels and achieving improved repulpability and regenerability.

[0103] In another exemplary embodiment, the above method can be further enhanced or accelerated by using a high shear mixing device, such as a medium consistency ("MC") pump (about 5% to 20% consistency) during the raw material preparation step. Further examples include a fiber furnish homogenizer that is primarily used for low consistency raw material mixing (about 0.1% to 5% consistency).

[0104] In another exemplary embodiment, the method may include synthesizing and using a novel wet strength agent by reacting vinylamide or CPAM polymer with glyoxal, oxidized lignin and laccase, rather than using UHMW GPVM. It is believed that the reaction produces a cationic polymer similar to an ultra-high molecular weight glyoxalated polyvinylamide adduct, but more rigid and branched by incorporating lignin into the polymer. Incorporating laccase during the synthesis method aids in the polymerization of oxidized lignin. Polyvinylpyrrolidone (PVP), polyvinylamine (PVAm), and / or anionic polyacrylamide (APAM) can react with the above-mentioned polymer to enhance the rigidity of the network. Figure 7 An exemplary chemical reaction for producing a novel wet strength agent according to an exemplary embodiment of the present invention through a strength composition is shown.

[0105] When this novel wet strength agent is mixed with cellulose fibers in the wet end of the wet laying process, the pendant aldehyde of the wet strength agent polymer (bonded to the polyvinylamide backbone via an amide alcohol bond) can react with the hydroxyl groups on the cellulose fibers to form hemiacetal bonds. Ionic bonds are also formed between the anionic charges on the cellulose fibers and the cationic charges of the wet strength agent polymer, and hydrogen bonds are also formed between the wet strength agent polymer and the cellulose fibers. The oxidized lignin incorporated into the wet strength agent polymer provides additional carboxyl groups to form hydrogen bonds with the hydroxyl groups on the cellulose fibers. In addition, the pendant aldehyde groups of the wet strength agent polymer can react with the amide groups of adjacent wet strength agent polymers during the crosslinking process to build a network of wet strength polymers that also adhere to the cellulose fibers, wherein the bonds have significant resilience to hydrolysis and thus provide wet strength. The branched structure of the wet strength agent polymer also provides improved accessibility to various cellulose fibers. Higher molecular weights are also preferred because the size of the wet strength agent polymer increases to further improve accessibility. Finally, this novel highly branched polymer with a high molecular weight increases the structural rigidity of the absorbent product to maintain the three-dimensional structure of the product, thereby keeping the product absorbent when wet. Figure 8 Exemplary chemical reactions are shown that illustrate the cross-linking of the novel wet strength agent with itself and the formation of a macrocomplex between GPAM and APAM according to an exemplary embodiment of the present invention.

[0106] It should be understood that the term "complex" as used herein does not require covalent bonds or other specific physical interactions between the components of the strength composition (e.g., UHMWGPVM and HMWAPAM components), although in some cases, such interactions may occur. In the context of the present invention, the components of the strength composition can be added to the raw material mixture together (e.g., in a premix) or separately and in any order of addition. As will be understood from the following examples, the components of the strength composition can be added to the raw material mixture together with any one or more other components of the strength composition (including any of those listed herein).

[0107] In an exemplary embodiment, the complex of anionic polyacrylamide resin and aldehyde functionalized polymer resin has a net anionic charge (as tested by the Mutek PCD03 test method). The amount of GPAM / APAM complex on or in the towel or tissue product can be about 0.25% to 1.5% based on the total weight of the product.

[0108] When used, polyvinylamine is not particularly limited and will be selected by those skilled in the art in view of the disclosure herein. Examples of polymers and polyvinylamines containing vinylamine that can be used include those of application Nos. 9,885,155, 9,879,380, 9,783,933, 5,753,759, 10,626,558, 10,618,992, 10,047,480, 8,926,797, 8,900,412, 8,894,816, 8,778,139, 8,696,869, 8,647,470, 8,614,279, 8,604,134, 8,518,215, 8,444,818, 8,440,768, 8,404,083, and 2,721,140, ​​the contents of which are incorporated herein by reference in their entirety.

[0109] In an exemplary embodiment, the complex of anionic polyacrylamide resin and aldehyde functionalized polymer resin has a net anionic charge (as tested by the Mutek PCD03 test method). The amount of GPAM / APAM complex on or in the paper or paperboard product may be about 0.05% to 1.5% based on the total weight of the product.

[0110] The paper or paperboard products are described below and will be further understood in light of the above methods. In general, the paper or paperboard products prepared using the compositions of the present invention can be, for example, paper towels, toilet paper, facial tissue, napkins, paper straws, scrubs, liquid packaging, aseptic liquid packaging, corrugated packaging, carrier packaging, and molded cellulose products, among others, as well as the additional product types described herein.

[0111] In some embodiments, the final paper or paperboard product may contain 70% to 99%, 80% to 99%, 85% to 99%, or 90% to 99% by weight of lignocellulosic fibers and 0.05% to 1.5% by weight of ultra-high molecular weight glyoxalated polyacrylamide adduct and high molecular weight anionic polyacrylamide complex.

[0112] In some embodiments, the final paper or paperboard product may comprise 70% to 99%, 80% to 99%, 85% to 99%, or 90% to 99% by weight of lignocellulosic fibers and 0.05% to 1.5% by weight of ultra-high molecular weight glyoxalated polyvinylamide adducts and high molecular weight anionic polyacrylamide complexes; and 0% to 0.5%, or 0.03% to 0.5% by weight of polyvinylamine.

[0113] The final paper or paperboard may contain other additives included in the formation of the paper or applied with the composition. Suitable additives are those used in paper. They include, but are not limited to, the following: inorganic and organic fillers, such as clay or hollow sphere pigments, optical brighteners, which are also called fluorescent whitening aids, pigments, dyes, strength additives, sizing agents, such as rosin, AKD, ASA, and waxes and inorganic salts. Specific examples are described in various places herein, for example with respect to the methods, and in the references incorporated herein.

[0114] The paper and paperboard produced according to the process of the invention are generally renewable, repulpable and capable of being recycled, which is highly desirable from an environmental point of view. In addition, for paper and paperboard produced using the inventive combination of ultra-high molecular weight glyoxalated polyacrylamide adduct and high molecular weight anionic polyacrylamide complex which may additionally contain PAE resin, a synergistic effect of improved wet and dry strength can be observed. This synergistic effect is unexpected and unanticipated.

[0115] Repulpability can be determined using a pulverizer as described in TAPPI Method T205 OM-88, (1988). Using this test, it has been found that paper made by the process of the present invention can be repulped in a much shorter time than the time required to repulp the same paper containing a conventional wet strength resin at approximately the same wet strength level.

[0116] Because repulpability depends on wet strength (i.e., for a given resin, the higher the wet strength, the lower the repulpability), different resins should be compared at the same wet strength. However, it is difficult to obtain papers with the same wet strength level but containing resins of different wet strengths. Therefore, a method was developed to normalize differences in repulpability for differences in wet strength. Since repulpability is inversely proportional to wet strength, such a "repulpability index" can be calculated as follows:

[0117] Repulpability Index = (Wet Tensile Strength) x (% Fiber Yield) / 100.

[0118] Therefore, higher Repulpability Index values ​​indicate better repulpability. For situations where the difference in wet strength is small, the Repulpability Index provides a good method for determining the relative difference in repulpability at the same wet strength.

[0119] Paper and paperboard with high wet strength are usually repulped with high shear energy and strong oxidizing chemicals with chlorine-containing chemicals such as sodium hypochlorite (bleach). Although non-chlorine-containing chemicals such as sodium persulfate, potassium persulfate, potassium peroxymonosulfate, sodium percarbonate and hydrogen peroxide are effective, chlorine-containing chemicals are generally more cost-effective. Very high shear forces and special equipment can also be used to repulp paper and paperboard with high wet strength, but high energy and additional capital costs are required.

[0120] As shown in Tappi Method T456; full saturation of some types of paper (particularly paperboard) can be significantly accelerated by immersion in (a) degassed distilled water, (b) normal distilled water, immersion under reduced pressure, or (c) by the addition of a wetting agent to the water. After extended immersion, changes in the pH of the immersion water caused by the sample and / or slow hydrolysis of any wet strength agent that may be present may cause further loss of strength.

[0121] It is well known that when fully wetted, paper treated with glyoxalated polyacrylamide resins is more repulpable than paper treated with PAE resins at the same initial wet strength (e.g., 10 second soak or 5 second Finch cup test). However, it has been unexpectedly discovered that paper treated with the ultra-high molecular weight glyoxalated polyacrylamide adducts of the present invention has improved repulpability at the same wet strength after 2 hours soaking and when fully wetted.

[0122] In one embodiment, the ultra high molecular weight glyoxalated poly(ethylene amide) adduct of the present invention has improved repulpability at the same wet strength after 2 hours soaking and when fully wetted.

[0123] When compared to a PAE resin treated paper or paperboard having substantially the same wet strength when fully wetted at ambient pH (i.e., without the addition of additional chemicals), the paper or paperboard made with the composition of the present invention can reduce the repulping time by more than 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% with a particular repulping process and with a comparable level of defibration. In addition, when compared to a PAE resin treated paper or paperboard having substantially the same wet strength when fully wetted and when the pH is increased to pH 8, 9, 10 and 11, the paper or paperboard made with the composition of the present invention can reduce the repulping time by more than 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%. The pH can be increased with any alkaline agent, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.

[0124] One embodiment of the present invention is a paper or paperboard product comprising 0 ppb to 300 ppb of 3-monochloro-1,2-propanediol (also known as 3-chloropropanediol and 3-MCPD) and 0 ppb to 50 ppb of 1,3-dichloro-2-propanol (also known as dichloropropanol and 1,3-DCP) and 0 wt % to 0.09 wt % of a polyaminoamide-epihalohydrin resin that meets or exceeds the requirements of the German Federal Institute for Risk Assessment (BfR) recommendations defining 1,3-DCP and 3-MCPD as extractable from various food contact grades of paper with water.

[0125] The paper or paperboard product according to an exemplary embodiment of the present invention comprises: 80 wt% to 99 wt% of cellulose fibers; and 0.05 wt% to 1.5 wt% of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex. The present invention uses ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex, which may additionally comprise: PAE resin and a product containing polyvinyl amine.

[0126] As another exemplary embodiment, the paper or paperboard product according to the present invention comprises: 80 wt% to 99 wt% of cellulose fibers; 0.05 wt% to 1.5 wt% of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex; and PAE wet strength resin. The present invention uses ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex, which may additionally comprise: PAE resin and a product containing polyvinyl amine.

[0127] As another exemplary embodiment, the paper or paperboard product according to the present invention comprises: 80 to 99 wt % of cellulose fibers; 0.05 to 1.5 wt % of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex; and a product containing polyvinyl amine.

[0128] The paper or paperboard product according to an exemplary embodiment of the present invention comprises: 80 wt % to 99 wt % of cellulose fibers; 0.05 wt % to 1.5 wt % of ultra-high molecular weight glyoxalated polyvinyl amide adduct and high molecular weight anionic polyacrylamide complex; and 0 wt % to 0.5 wt %, or 0.03 wt % to 0.5 wt % of polyvinyl amine.

[0129] A paper or paperboard product according to an exemplary embodiment of the present invention comprises cellulose fibers, a concentration of less than 50 ppb of dichloropropane and a concentration of less than 300 ppb of 3-chloropropanediol, and provides a wet tensile strength of at least 10%, for example 15%, 20%, or 25%, or 30% of the dry tensile strength value, wherein the product comprises 0% to 0.09% by weight of polyaminoamide-epihalohydrin.

[0130] A paper or paperboard product according to an exemplary embodiment of the present invention comprises cellulose fibers, a concentration of less than 50 ppb of dichloropropane and a concentration of less than 300 ppb of 3-chloropropanediol, and provides a wet tensile strength of at least 10%, for example 15%, 20%, or 25%, or 30% of the dry tensile strength value, wherein the product is free of polyaminoamide-epihalohydrin as measured using the "adipic acid test".

[0131] The absorbent product according to an exemplary embodiment of the present invention has a thickness in the range of about 600 μm to about 1500 μm, or 700 μm to 1300 μm, or 725 μm to 1200 μm, or 735 μm to 1100 μm.

[0132] In exemplary embodiments, the CD wet strength of the absorbent product is in the range of about 75 N / m to about 200 N / m, or 80 N / m to 150 N / m, or 85 N / m to 145 N / m.

[0133] In exemplary embodiments, the absorbent product has a wet thickness ranging from about 400 μm to about 800 μm, or from 450 μm to 650 μm, or from 470 μm to 575 μm.

[0134] In exemplary embodiments, the absorbent product has a basis weight of from about 35 gsm to about 65 gsm, or from 38 gsm to 52 gsm, or from 38 gsm to 50 gsm, or from 39 gsm to 42 gsm.

[0135] In exemplary embodiments, the absorbent product has a CD Dry Strength of about 275 N / m to about 600 N / m, or 325 N / m to 525 N / m, or 375 N / m to 485 N / m, or 380 N / m to 450 N / m.

[0136] In exemplary embodiments, the absorbent product has an absorbency of about 11 g / g to about 18 g / g, or 12.5 g / g to 16.0 g / g, or 13.5 g / g to 15.5 g / g as measured according to the GATS method.

[0137] According to an exemplary embodiment of the present invention, the absorbent product comprises about 95% by weight to about 99% by weight, or about 97% by weight to about 99% by weight of cellulose fibers; about 0.2% by weight to about 1.5% by weight, or about 0.05% by weight to about 1.5% by weight of high molecular weight anionic polyacrylamide; and about 0.2% by weight to about 0.8% by weight, or about 0.05% by weight to about 0.5% by weight of ultra-high molecular weight glyoxalated polyvinylamide adducts. In one embodiment, GPAM has a cationic charge density of 0.6meq / g or less (as tested by the Mutek PCD03 method). In an exemplary embodiment, the absorbent product comprises a biopolymer to replace the high molecular weight anionic polyacrylamide or to combine with the high molecular weight anionic polyacrylamide.

[0138] The absorbent product according to an exemplary embodiment of the present invention is substantially free of CPD, DCP and PAE. As used herein, the term "substantially free of" means that the paper contains: less than 550 parts per billion ("ppb") or about 50ppb to about 550ppb of CPD; or less than about 200ppb, or about 30ppb to about 200ppb of DCP, or about 5ppb to 50ppb of DCP in the paper, and less than about 0.06% by weight of PAE in the paper, or no PAE resin is added to the wet end of the paper machine. The PAE in the paper can be 0.00% by weight to 0.09% by weight, or 0.00% by weight to 0.03% by weight, or 0.01% by weight to 0.04% by weight. Although the present invention can be achieved by adding 2.5kg / ton of PAE resin to the wet end of the paper machine, the paper has the above-mentioned very low PAE or CPD / DCP, while obtaining high wet strength, high fluffiness and absorbency.

[0139] In an exemplary embodiment, the absorbent structure is a two-ply tissue roll item sold as retail tissue.

[0140] The absorbent product according to an exemplary embodiment of the present invention has a wet transverse tensile strength of 75 to 200 N / m, preferably 80 to 150 N / m, and most preferably 85 to 145 N / m.

[0141] Absorbent structures prepared according to the methods of exemplary embodiments of the present invention include, but are not limited to, disposable tissues, napkins, and facial products.Multi-layer absorbent structures can be laminated together using any of the aforementioned lamination techniques to improve overall absorbency or softness.

[0142] Figure 6 A flow chart of a method for manufacturing a tissue product according to an exemplary embodiment of the present invention is shown. As shown, the tissue product is made using a through-air drying process on a wet laid product with a three-layer headbox. All three layers of the tissue are made from 75% northern bleached softwood kraft paper and 25% eucalyptus. As shown in step 01, the eucalyptus is conveyed from box A to mixing tank 1. In step 02, NSBK is conveyed from box B to mixing tank 2 and is refined separately before being mixed into the layers (step 03). Similarly, before being mixed into the layers, in step 04, the NSBK is mixed with a GPVM adduct (e.g., as Hercobond TM Plus 555 dry strength additive sold by Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA Tel: +1-866-337-1533). In step S06, NSBK mixed with GPVM adduct is added to mixing tank 2 to obtain a mixture of 75% NSBK and 25% eucalyptus. In step S07, the mixture is conveyed to the headbox while HMWAPAM (e.g., Hercobond 555 sold by Solenis) is added to the headbox. TM 2800 dry strength additive) and polyvinyl amine retention aids (e.g., Hercobond TM 6950 Dry Strength Additive) was added to the mixture.

[0143] Test Method

[0144] All tests are performed on prepared samples that have been conditioned for at least 2 hours in an air-conditioned room at 23 + / - 1.0°C and 50.0% + / - 2.0% relative humidity, except for the softness test, which requires conditioning for 24 hours at 23 + / - 1.0°C and 50.0% + / - 2.0% relative humidity.

[0145] Ball Burst Test

[0146] The ball burst of a 2-ply tissue or paper towel web is determined using a Tissue Softness Analyzer (TSA) available from Emtec Electronic GmbH, Leipzig, Germany, using a ball burst head and handle. The instrument is calibrated annually by an external vendor according to the instrument manual. The balance on the TSA is verified and / or calibrated prior to the burst analysis. Once the burst adapter and test ball (16 mm diameter) are connected to the TSA, the balance is zeroed. The test distance from the test ball to the sample is calibrated. Five circular samples are cut from the web using a 112.8 mm diameter circular punch. One of the samples is loaded into the TSA with the embossed surface facing up, positioned above the handle and secured in place using a ring. The ball burst algorithm "Berst Resistance" is selected from the list of available softness test algorithms displayed by the TSA. The TSA then pushes the ball burst head through the sample until the web breaks and calculates the force (in Newtons) required for the break to occur. The testing process is repeated for the remaining samples and the results for all samples are averaged and then converted to grams-force.

[0147] For more detailed instructions on operating the TSA, measuring ball burst and calibration instructions, refer to the "Leaflet" or "Operating Instructions" manual provided by Emtec.

[0148] Wet Bulb Burst Test

[0149] The wet ball burst of a 2-ply tissue or paper towel web is determined using a Tissue Softness Analyzer (TSA) available from Emtec Electronic GmbH, Leipzig, Germany, using a ball bursting head and a handle. The instrument is calibrated annually by an external supplier according to the instrument manual. The balance on the TSA is verified and / or calibrated prior to the burst analysis. Once the burst adapter and test ball (16 mm diameter) are connected to the TSA, the balance is zeroed. The test distance from the test ball to the sample is calibrated. Five circular samples are cut from the web using a 112.8 mm diameter circular punch. One of the samples is loaded into the TSA with the embossed surface facing up, positioned above the handle and secured in place using a ring. The ball burst algorithm "Berst Resistance" is selected from the list of available softness test algorithms displayed by the TSA. One milliliter of water is placed in the center of the sample using a pipette and a wait of 30 seconds is allowed before starting the measurement. The TSA then pushes the ball bursting head through the sample until the web bursts and calculates the force (in Newtons) required for the burst to occur. Repeat the testing process for the remaining samples and average the results for all samples and convert to grams-force.

[0150] For more detailed instructions on operating the TSA, measuring ball burst and calibration instructions, refer to the "Leaflet" or "Operating Instructions" manual provided by Emtec.

[0151] Tensile & MD, CD, and wet CD tensile strength testing

[0152] A Thwing-Albert EJA series tensile tester manufactured by Thwing Albert of West Berlin, NJ, an Instron 3343 tensile tester manufactured by Instron of Norwood, MA, or other suitable vertical extension tensile tester, which can be configured in various ways, typically using 1 inch or 3 inch wide strips of tissue or paper towel, can be used to measure stretch as well as MD, CD, and wet CD tensile strength. The instrument is calibrated annually by an outside vendor according to the instrument manual. The jaw separation speed and the distance between the jaws (grips) are verified before use, and the balance is "zeroed". A pre-tension or relaxation correction of 5 N / m must be met before starting extension for measurement. After calibration, 6 strips of 2-ply product are cut using a 25.4 mm × 120 mm die. When testing MD (longitudinal direction) tensile strength, the strips are cut along the MD direction. When testing CD (cross-machine direction) tensile strength, the strips are cut along the CD direction. One of the sample strips is placed between the upper jaw faces and clamped, then carefully straightened (without tensioning the sample) and the sample (freely hanging from the upper jaws) is clamped 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, the sample strips are tested to obtain tensile strength and peak elongation (as defined by TAPPI T-581 om-17). The testing procedure is repeated until all samples have been tested. The values ​​obtained for the six sample strips are averaged to determine the tensile strength and peak elongation in the MD and CD directions. When testing CD wet tensile, the strips are placed in an oven at 105°C for 5 minutes and saturated with 75 microliters of deionized water in the center of the strip across the entire transverse direction immediately before pulling the sample.

[0153] Basis Weight

[0154] Using the dye and press, cut six 76.2mm x 76.2mm square samples from the 2-ply product, being careful to avoid any mesh perforations. Place the samples in an oven at 105°C for at least 3 minutes and then immediately weigh on an analytical balance to the fourth decimal place. Multiply the sample weight in grams by 172.223 to determine the basis weight in grams per square meter. Test the samples individually and average the results. The balance should be verified prior to use and calibrated annually by an outside vendor according to the instrument manual.

[0155] Thickness test

[0156] A Thwing-Albert ProGage 100 Thickness Tester Model 89-2012 manufactured by ThwingAlbert ofWest Berlin, NJ was used for thickness testing. The instrument was verified prior to use and calibrated annually by an outside vendor according to the instrument manual. The thickness tester used a 2-inch diameter presser foot, a preset load of 95 grams per square inch, a measurement speed of 0.030 inches per second, a dwell time of 3 seconds, and a fixed load of 298.45 g. Six 100 mm by 100 mm square samples were cut from the 2-ply product with the embossed pattern facing up. The samples were then tested individually and the results averaged to obtain the thickness result in microns.

[0157] Wet Thickness

[0158] A Thwing-Albert ProGage 100 thickness tester model 89-2012 manufactured by ThwingAlbert ofWest Berlin, NJ was used for thickness testing. The instrument was verified prior to use and calibrated annually by an outside vendor according to the instrument manual. The thickness tester used a 2-inch diameter presser foot, a preset load of 95 grams per square inch, a measurement speed of 0.030 inches per second, a dwell time of 3 seconds, and a fixed load of 298.45 g. Six 100 mm by 100 mm square samples were cut from the 2-ply product with the embossed pattern facing up. Each sample was placed in a container that had been filled with deionized water to a three-inch level. The container was large enough to place the sample on the water surface without folding the sample. The sample was placed in the water in the container for 30 seconds, then removed and tested for thickness using the ProGage. The samples were tested individually and the results were averaged to obtain a wet thickness result in microns.

[0159] Softness test

[0160] The softness of a 2-ply tissue or paper towel web is determined using a Tissue Softness Analyzer (TSA) available from Emtec Electronic GmbH of Leipzig, Germany. The TSA consists of a rotor with vertical blades that rotates on a test block to apply a defined contact pressure. The contact between the vertical blades and the test block generates vibrations that are detected by a vibration sensor. The sensor then transmits the signal to a PC for processing and display. The frequency analysis in the range of approximately 200 Hz to 1000 Hz represents the surface smoothness or texture of the test block and is called the TS750 value. Another peak in the frequency range of 6 kHz to 7 kHz represents the overall softness of the test block and is called the TS7 value. Both TS7 and TS750 values ​​are expressed in dB V2 rms. The stiffness of the sample is also calculated when the device measures the deformation of the sample under a defined load. The stiffness value (D) is expressed in mm / N. The device also calculates the Hand Feel (HF) number, which corresponds to the softness felt when someone touches the sample with their hand (the higher the HF number, the higher the softness). The HF number is a combination of sample TS750, TS7 and Stiffness as measured by TSA and calculated using an algorithm that also requires sample thickness and basis weight. Different algorithms may be selected for different facial tissue, sanitary tissue, and tissue products. Prior to testing, a calibration check should be performed using "TSA Leaflet No. 9" obtained from emtec. If the calibration check shows that calibration is necessary, follow "TSA Leaflet No. 10".

[0161] Cut five circular samples from the web using a 112.8mm diameter circular punch. Load one of the samples into the TSA, clamp it in place (facing outward or with the embossed layer facing up), and select the TPII algorithm (when testing bath towels) and the Facial II algorithm (when testing paper towels) from the list of available softness test algorithms displayed on the TSA. After entering the sample parameters (including thickness and basis weight), run the TSA measurement program. Repeat the test process for the remaining samples, and average the results of all samples and record the average HF number.

[0162] For more detailed instructions on operating the TSA, measuring softness and calibration, refer to the Leaflet or Operating Instructions manual provided by Emtec.

[0163] Absorption test

[0164] The M / K GATS (Gravimetric Absorbency Test System) manufactured by M / K Systems, Inc., of Peabody, MA, USA, tests absorbency using the MK Systems GATS manual as of June 29, 2020. The instrument is calibrated annually by an outside vendor according to the manual. Absorbency is expressed in grams of water absorbed per gram of absorbent product. The following steps are followed in the absorbency test procedure:

[0165] Turn on the computer and the GATS machine. The main power switch for the GATS is located on the left front of the machine and will light up red when powered on. Make sure the balance is switched on. The balance should not be used to measure masses for at least 15 minutes after it has been switched on. Click on the "MK GATS" icon to start the computer program and once the program has loaded click on "Connect". If there are connection problems make sure the correct ports are connected to the GATS and balance. These can be seen in full operational mode. The upper reservoir of the GATS needs to be filled with deionized water. The level of the Velmex slides in the wetting station is set to 6.5cm. If the slides are not at the proper level, their movement can only be accomplished in full operational mode. Click on the "Direct Mode" checkbox located in the upper left corner of the screen to take the system out of direct mode and into full operational mode. The level of the wetting station is adjusted in the third window from the left side of the software screen. To move the slide up or down 1cm at a time, use the "Up 1cm" and "Down 1cm" buttons. If millimeter adjustments are required, hold down the Shift key while toggling the "Up 1cm" or "Down 1cm" icons. This will move the wetting table 1mm at a time. Click on the Test Options icon and ensure the following set points are entered: Select Immersion Start and enter 10.0mm under Absorption, Select Total Weight Change (g) and enter 0.1 under Start Position, Select Rate (g) and enter 0.05 per 5 seconds under End Position on the left side of the screen, Under Desorption enter 1 for Number of Rise and 10 for Rise (mm), Select Rate (g) and enter -0.03 per 5 seconds under End Position on the right side of the screen. Before any series of tests are carried out, the water level in the main reservoir needs to be filled to the operating level. This involves setting the total mass of the reservoir and the water contained therein to 580 grams. Click on the Set Up icon in the box in the upper left corner of the screen. The reservoir needs to be lifted to allow the balance to weigh or zero itself. The feed and extraction tubes to the system are located on the side and extend into the reservoir. Before lifting the reservoir, ensure the top hatch of the balance is open to avoid damaging the top of the balance or the elevated platform used to weigh the sample. Open the side door of the balance and lift the reservoir. Once the balance reading is stable, a message will appear to place the reservoir again. Ensure the reservoir does not touch the wall of the balance. Close the side door of the balance. The reservoir will need to be filled to obtain a mass of 580g. Once the reservoir is filled, the system is ready for testing. Obtain at least four round samples with a diameter of 112.8mm. Three will be tested, with one extra. Enter the relevant sample information in the software's "Enter Material ID" area. The software will automatically date and number the completed sample and enter any user entered data in the center of the file name. Click the "Perform Test" icon. The balance will automatically zero. Place the pre-cut sample on the elevated platform, ensuring the sample does not touch the balance lid. Once the balance load is stable, click "Weigh". Move the sample to the aluminum test plate on the wet bench, centered with the embossed side facing down. Ensure the sample does not touch the sides and place the lid on the sample.Click "Wet Sample". The wetting table drops a preset distance to begin absorption (10 mm). Absorption ends when the absorption rate is less than 0.05 grams per 5 seconds. When absorption stops, the wetting table rises for desorption. Desorption data is not recorded for the test sample. Before the next test, remove the saturated sample and dry the wetting table. Once the test is completed, the system automatically fills the reservoir. Record the data generated for this sample. The data tracked for each sample is the dry weight of the sample in grams, the standardized total absorption rate of the sample reflected in grams of water / gram of product, and the standardized absorption rate expressed in grams of water per second. Repeat this procedure for three samples and report the average total absorbency.

[0166] Wet scrubbing

[0167] The Wet Scrub Test is used to measure the durability of wet wipes. The test involves rubbing a sample wet wipe with an abrasion tester and recording the number of revolutions required for the tester to break the sample. Multiple samples of the same product are tested and the average durability of the product is determined. The measured durability is then compared to similar durability measurements of other wet wipe samples.

[0168] An abrasion tester was used for the wet scrubbing test. The specific abrasion tester used was the M235 Martindale Abrasion and Pilling Tester ("M235 Tester") from SDL Atlas Textile Testing Solutions. The M235 Tester provides multiple abrasion stations on which samples are abraded and a sample holder for abrading tissue samples so that multiple tissue samples can be tested simultaneously. A moving plate is located above the abrasion station and moves the sample holder near the abrasion station for abrasion.

[0169] In preparation for testing, eight (8) tissue samples were cut to have a diameter of about 140 mm (about 5.51 inches). In addition, four (4) pieces were cut from a non-textured polymer film having a thickness of about 82 ± 1 μm, also having a diameter of about 140 mm (about 5.51 inches). The non-textured side of the vacuum sealed bag served as the non-textured polymer film. However, any non-textured polymer film may be used, such as high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), or polyester, to name a few. In addition, four (4) circular pieces of 38 mm diameter were cut from a textured polymer film having protruding channels on the surface to provide roughness. The textured polymer film used for this test was SC Johnson's Textured side of the vacuum seal bag. Textured film has a square pattern ( Figure 5). The thickness of the protruding channels of the textured polymer film used was about 213±5 μm, and the thickness of the film in the valley area of ​​the textured film between the protruding channels was about 131±5 μm. The samples were cut using a 140 mm and 38 mm diameter cutting die and a knife cutting press, respectively.

[0170] Figure 2 An example of a wear station used in conjunction with an M235 tester is shown. Figure 2 An exploded view of the tissue sample connected to the wear table 202 is shown. To insert each sample to be tested into the wear table, the moving plate of the wear table is removed from the tester, the clamp ring 214 is unscrewed, a piece of smooth polymer film 210 is placed on the wear table 202, and then the tissue sample 212 is placed on top of the smooth polymer film 210. Figure 3 As shown, a load weight 215 is temporarily placed on top of the sample 212 on the wear table 202 to hold everything in place while the clamp ring 214 is reattached to the wear table 202 to hold the tissue sample 212 in place.

[0171] refer to Figure 4 Each wear station 202 in the M235 tester has a corresponding sample holder for wear testing. The sample holder is assembled by inserting a piece of textured polymer film 216 into a sample holder insert 218, which is placed under the sample holder body 220 and held in place under the sample holder body 220 using a sample holder nut (not shown). A spindle 222 is mounted to the top center of the sample holder body 220. Figure 5 Shows Figure 4 A top view of the textured polymer film 216 is shown.

[0172] The M235 tester was then turned on and a cycle time of 200 revolutions was set. 0.5 mL of water was placed on each tissue sample. After waiting 30 seconds, the scrubbing test was started, rotating the sample holder 206 200 revolutions. The number of revolutions required to destroy each sample on the corresponding wear station 202 (the "web scrub resistance" of the sample) was recorded. The results of the samples for each product were averaged, and the products were then rated based on the average.

[0173] Test method for characterizing charge density of HMWAPAM

[0174] Anionic polyacrylamide systems are characterized by molecular weight and charge density. For measuring charge density, a Mutek PCD-05 particle charge detector was used. Anionic polyacrylamide samples were diluted to approximately 0.04 wt % in deionized water, and 2 mL of this solution was then added to 8 mL of 0.01 M phosphate buffer at pH 6 in a Mutek assay cell. The samples were titrated to a streaming potential of 0 mV with polydiallyldimethylammonium chloride ("polyDADMAC"). The reported values ​​are based on the dry weight of the polymer.

[0175] Test method for molecular weight characterization of HMWAPAM

[0176] Anionic polyacrylamide molecular weight properties and weight average molecular weight (Mw) were determined using size exclusion chromatography (SEC) under the following conditions:

[0177] Mobile phase: 0.1M sodium nitrate / 20% acetonitrile

[0178] Flow rate: 0.8 mL / min

[0179] Chromatographic columns: 2 TSKgel GMPWxl columns connected in series

[0180] Column temperature: 40°C

[0181] DRI detector temperature: 40°C

[0182] Calibration: relative to poly(acrylic acid) sodium salt, narrow molecular weight standards

[0183] Sample concentration: Typically, 2 mg / mL in mobile phase

[0184] Sample preparation: Stir in mobile phase for 1 to 2 hours

[0185] Filtration: 0.45μm PVDF injector filter

[0186] Batch Mode MALS Testing Method

[0187] Instrument: Wyatt DAWN HELEOS (18 angle light scattering detector) with flow-through batch kit. The instrument was calibrated using toluene and normalized using a narrow PEG standard of approximately 130K. The following parameters were used:

[0188] Mobile phase: 0.2 M LiNO filtered through a 0.22 μm filter 3 / / 0.5M acetic acid

[0189] Sample concentration: 0.2 mg / mL

[0190] dn / dc: 0.167mL / g

[0191] Sample preparation: The received samples were dissolved in the mobile phase in a dust-free glass vial and tumbled for 1 hour at room temperature before being transferred to a scratch-free and dust-free scintillation vial prepared prior to the batch-mode MALS experiment. The sample solution was analyzed without filtration. Batch-mode MALS data were processed using Astra 7 software.

[0192] AF4-MALS test method

[0193] A PostNova Asymmetric Flow Field Flow Fractionation (AF4) system was used to perform AF4-MALS experiments. The system was calibrated using bovine serum albumin standards, and all 21 angles in the light scattering detector were normalized using 64K narrow polystyrene sulfonate standards prior to sample analysis. The received GPAM samples were dissolved in the mobile phase in a dust-free glass vial and tumbled for 1 h at room temperature. The sample solution was then transferred to a 2 mL autosampler vial and analyzed using AF4-MALS without filtration.

[0194] AF4 conditions:

[0195] Mobile phase: 0.2 M LiNO filtered through a 0.22 μm filter 3 / 0.5M acetic acid

[0196] Concentration: 5mg / mL

[0197] Injection volume: 40 μL

[0198] dn / dc: 0.167mL / g

[0199] Membrane: 10K PES

[0200] Spacer: 350μm

[0201] AF4 method:

[0202] Detector flow rate: 0.50mL / min

[0203] Trough outlet flow rate: 0.00mL / min

[0204] Spacer: 350μm

[0205] Focus

[0206] Injection flow rate: 0.20mL / min

[0207] Injection time: 7.00min

[0208] Cross flow rate: 2.30mL / min

[0209] Transfer time: 1.00min

[0210] Elution step △t[min] From [mL / min] To [mL / min] type index 1 3.00 2.30 2.30 constant ---- 2 5.00 2.30 1.70 power 0.2 3 1.00 1.70 1.70 constant ---- 4 15.00 1.70 0.05 power 0.35 5 25.00 0.05 0.05 constant ---- 6 17.00 0.05 0.00 constant ----

[0211] rinse

[0212] Tip pump: 0.55mL / min

[0213] Focus pump: 0.00mL / min

[0214] Tank pump: 0.00mL / min

[0215] Time: 0.50min

[0216] Open the flushing valve

[0217] Zeta potential test method

[0218] Zeta potential was measured using a Wyatt Mobius. Samples were collected as received (1.970 mg / mL, diluted in 0.5 MAcOH / 0.2 LiNO 3 The samples were tested in quartz colorimetric tubes with immersion cells. The instrument parameters used were as follows:

[0219] Set the type of data collected: DLS and PALS (simultaneously)

[0220] Auto decay enabled Set DLS acquisition time (s): 1

[0221] Set DLS acquisition times: 5

[0222] Set voltage amplitude (V): 3

[0223] Set electric field frequency (Hz): 10.0

[0224] Set PALS collection period(s): 5

[0225] Laser mode: Normal

[0226] Set temperature (℃): 25

[0227] ZP Mode: Smoluchowski

[0228] Laser wavelength: 532nm

[0229] Test Methods for Comparing Repulpability

[0230] Sample preparation of target 5% slurry:

[0231] Weigh the submitted sample to determine the number of tests possible per test at 18 grams. If 18 grams is not available, determine the lowest amount available and run everything at that weight. If possible, cut the sample into 1 / 2 inch squares until 18 grams is achieved. Calculate the amount of DI water by subtracting the sample weight from 360 grams (342 grams for 5%).

[0232] Device Setup

[0233] Connect the temperature controller and motor controller to the timer. Set the temperature controller to the target temperature (125°F for the present invention). Set the motor controller to 750 rpm for adding the prepared sample. Check the glass Wein blender bottle (Fisher 14-509-11A) with the blade assembly (Fisher 14-509-12) for leaks. Clamp the blender bottle in place and insert the heating pad wrapped around the blender bottle.

[0234] Repulping

[0235] Pour the amount of water required for repulping into the bottle, put the blender bottle cap (Fisher 14-509-11D) in place, and insert the temperature probe so the blade does not hit it, clamping it in place. Turn on the timer and allow the water to agitate (750 rpm) and come up to temperature. Move the cap and probe to the side. If necessary, add chemicals to improve repulping. Measure pH. If necessary, adjust pH with NaOH or H 2 SO 4 The aqueous solution is adjusted to the desired level. Slowly add the cut sample, feeding into the bottle takes at least 5 minutes. Reset the cap and probe, set the motor controller to the desired speed (1500rpm for the present invention), and set the timer to 15 minutes. After 15 minutes, the motor turns off, takes a teaspoon of slurry (may need to take 2 times), and puts it into a 4oz container. Add 100mL of DI water to the slurry and stir with a spoon. Pour the contents onto a blue glass plate. Compare with a Brecht Zippel IndexChart. Record the results. Stir the pulp to remove any accumulation under the blade. Repeat the first four steps until 120 minutes have passed or the slurry is completely repulped. Measure the final pH.

[0236] Results Report

[0237] Compare the diluted slurry (see 3.9) to the Brecht Zippel Index Chart, collecting data every 15 minutes. Report these values ​​(up to 8 for 2 hours), and the final data point collected is the final result.

[0238] Test Methods Comparing Paper and Paperboard

[0239] Containerboard paper was made using a medium-duty paper machine. The pulp was 100% recycled media with 50 ppm hardness, 25 ppm alkalinity, 2.5% GPC D28F oxidized starch (Grain Processing Corp., Muscatine, Iowa) and 2000 uS / cm conductivity (adjusted with sodium sulfate). The system pH was 7.0 at 50°C, unless otherwise stated, the pulp freeness was about 325 CSF, and the stock temperature was 50°C. The basis weight was 160 grams per square meter (gsm). Unless otherwise stated, the PerForm TM PC 8713 flocculant (Solenis LLC, Wilmington, Del.) was added to the wet end of the paper machine at 0.0125% of dry pulp. The additives described in the examples were added to the wet end of the paper machine as either wet strength agents or dry strength agents at the specified levels, expressed as a weight percent of polymer active relative to dry pulp. The strength effects of the chemical treatments were measured using ring crush, Mullen burst, short span compression test, tensile and tear tests.

[0240] Paper Test

[0241] Before the paper properties were tested, the papers were aged naturally, referring to papers treated according to TAPPI method T402. All the papers tested were aged naturally for more than two weeks at 50% + / - 2% relative humidity and 23°C + / - 1°C.

[0242] Mullen (TAPPI Test Method T-403)

[0243] This test is used to measure the burst strength or puncture resistance of a paper sample. The pre-treated test sample is firmly clamped between two metal rings of a BFPerkins C Mullen tester, completely covering the rubber diaphragm. The trip lever is placed in the forward position to apply hydrostatic pressure, causing the rubber diaphragm to expand until the paper sample bursts. When the test sample bursts, the lever is moved to the reverse position and the burst strength is recorded. Wet burst strength is determined in a similar manner, except that the sample is completely wetted for 2 hours.

[0244] Ring Compression Test (RCT) (TAPPI Test Method T-822)

[0245] This test is used to measure the compressive strength of paper samples. A Lorentzen & Wettre crush tester is used to perform this test. A die is used to cut 152.4mm x 12.7mm strips from the treated sample. The strips are slid into the sample holder so that the sample remains in a ring shape. The sample holder is placed on the lower platen. The load is applied at a constant rate of 12.5mm / min until the sample fails and the load is recorded in lbf / 6in. Five repetitions are performed in each of the transverse and longitudinal directions. The final reported value is the geometric mean of the transverse and longitudinal direction values.

[0246] Short span compression test (STFI) was determined using TAPPI method T826, and dry tensile strength was determined using TAPPI method T494. Wet tensile strength was determined using TAPPI method T456 with immersion times of 10 seconds and 2 hours.

[0247] Kymene TM The 1500LV wet strength resin is a PAE resin (available from Solenis LLC, Wilmington, DE) and is abbreviated in the table as K1500LV. TM The 1044 dry strength additive is HMWAPAM (available from Solenis LLC, Wilmington, DE) and is abbreviated in the table as H1044. TM Plus 555 dry strength additive is UHMW GPVM (available from Solenis LLC, Wilmington, DE) and is abbreviated in the table as H555. TM The 1000 dry strength additive is a conventional GPAM (available from Solenis LLC, Wilmington, DE) and is abbreviated in the table as H1000. TM The 2000 dry strength additive is a conventional APAM (available from Solenis LLC, Wilmington, DE) and is abbreviated in the table as H2000.

[0248] The data in the table below show that Kymene TM The wet and dry strength properties of 1500LV wet strength resin (Comparative Example 1, CE1) were improved by adding Hercobond TM 1044 dry strength additive (see Comparative Example 2, CE2). Hercobond TM The wet and dry strength properties of Plus 555 dry strength additive (Example 1, Ex1) were improved by adding Hercobond TM1044 dry strength additive (see Example 2, Ex2).

[0249] It has been unexpectedly discovered that Example 2 has much less wet tensile loss relative to Example 1 from 10 seconds soak to 2 hours soak.

[0250] It was also unexpectedly discovered that Example 2 had much higher wet tensile and % wet tensile / dry tensile than using conventional GPAM and conventional APAM (see Comparative Example 3, CE3).

[0251] It was also unexpectedly found that Example 2 had much greater wet tear strength than using conventional GPAM and conventional APAM (see Comparative Example 3, CE3). High wet tear strength is especially important for some paperboard grades (e.g., carrier board). In addition, Example 2 provides enhanced dry Mullen burst strength, ring crush strength, and STFI compression strength relative to conventional GPAM and conventional APAM (see Comparative Example 3, CE3), thereby allowing the production of, for example, improved recycled linerboard, media paper, and corrugated boxes.

[0252] run First Mixer Added dry basis % Third mixer Added dry basis % Fourth mixer Added dry basis % CE0 blank 0.00 blank 0.00 blank 0.00 CE1 K1500LV 0.40 blank 0.00 blank 0.00 CE1 K1500LV 0.50 blank 0.00 blank 0.00 CE1 K1500LV 0.60 blank 0.00 blank 0.00 CE2 K1500LV 0.40 H1044 0.14 H6350 0.02 CE2 K1500LV 0.50 H1044 0.18 H6350 0.02 Exl H555 0.40 blank 0.00 blank 0.00 Exl H555 0.60 blank 0.00 blank 0.00 Exl H555 0.80 blank 0.00 blank 0.00 Ex2 H555 0.40 H1044 0.14 H6350 0.02 Ex2 H555 0.60 H1044 0.21 H6350 0.02 Ex2 H555 0.80 H1044 0.29 H6350 0.02 CE3 H1000 0.40 H2000 0.14 H6350 0.02 CE3 H1000 0.60 H2000 0.21 H6350 0.02 CE3 H1000 0.80 H2000 0.29 H6350 0.02

[0253]

[0254]

[0255] Test methods for detecting PAE in products

[0256] PAE can be measured by the method taught in "Determination of wet strength resin in paper by pyrolysis-gas chromatography" (Paper Properties, Tappi Journal, February 1991, pages 197-201), which is incorporated herein by reference in its entirety. PAE is measured indirectly by measuring cyclopentanone. A vertical microfurnace pyrolyzer (Yanagimoto GP-1018) is directly connected to a gas chromatograph (Shimadzu GC 9A) equipped with a flame ionization detector and a flame thermal ionization detector. About 0.5 mg of toilet paper goods or paper towels are pyrolyzed under a nitrogen or helium carrier gas flow. The pyrolysis temperature is set empirically at 500°C. A fused silica capillary column (50m×0.25mm id, Quadrex) coated with a chemically cross-linked fixed free fatty acid phase (FFAP, 0.25μm thick) is used. The carrier gas flow rate of 50mL / min in the pyrolyzer is reduced to 1mL / min in the capillary column by a splitter. The column temperature was initially set to 40°C and then increased to 240°C at a rate of 4°C per minute. The pyrolysis chromatographic peaks were identified using a gas chromatograph-mass spectrometer (Shimadzu QP-1000) with an electron impact ion source. Cyclopentanone standards were prepared and a calibration curve was generated, and then the tissue goods or paper towel samples were measured according to the curve.

[0257] The product may be contaminated with PAE from the Yankee coating. To eliminate this problem, repeat the above test method 10 times and eliminate the data for intermittent high levels of PAE. Another method to determine if PAE is caused by surface contamination of the Yankee coating is to use the Tape Layer Purity Test to remove the Yankee layer from both layers of a two-ply tissue, napkin, or facial product. Care must be taken to ensure that the surface that the Yankee surface contacts is the surface that is removed by the tape. Some tissue products can be reverse laminated, with the Yankee side in or Yankee side laminated to the Yankee side. After removing the Yankee layer, perform the above test method on the sample.

[0258] Alternatively, PAE testing can be performed by Intertek Polychemlab BV, Koolwaterstofstraat 1, 6161 RA Geleen, The Netherlands.

[0259] A typical sample analysis comprises the following: 0.2 grams of sample material is added to 10 mL of 37% aqueous hydrochloric acid solution containing pimelic acid (CAS 111-16-0) as an internal standard. This mixture is digested at 150° C. for 2 hours using a microwave. The resulting solution is transferred to a 50 mL flask and measured using liquid chromatography-mass spectrometry, using adipic acid (CAS 124-04-9) and glutaric acid (CAS 110-94-1) as external standards. Internal standard correction is not applied. All PAE values ​​in this patent application are expressed in weight % of adipic acid and glutaric acid values ​​combined.

[0260] Test methods for detecting DCP and CPD

[0261] DCP and CPD were measured by ACOC official method 2000.01, which is incorporated herein by reference in its entirety. Weigh 25mg CPD (98% isotopic purity, available from Sigma-Aldrich Company) and put it in a 25mL volumetric flask and dilute to scale with ethyl acetate to prepare 1mg / mL CPD stock solution. Dilute 1mL CPD stock solution with 9mL ethyl acetate to prepare 100μg / mL CPD intermediate standard solution. 2mL CPD intermediate standard solution was pipetted into a 100mL volumetric flask and diluted to scale with ethyl acetate to prepare 2μg / mL CPD spiked solution (spiking solution). Weigh 25mgCPD-d5 and put it in a 25mL volumetric flask and dilute to scale with ethyl acetate to prepare 1mg / mL CPD-d5 internal standard stock solution. Dilute 1mL CPD-d5 internal standard stock solution in 100mL ethyl acetate to prepare 10μg / mL CPD-d5 internal standard working solution. The 100 μg / mL intermediate standard solution was pipetted into 25 mL volumetric flasks in aliquots of 0 μL, 12.5 μL, 25 μL, 125 μL, 250 μL, and 500 μL and diluted to the mark with 2,2,4-trimethylpentane to obtain CPD concentrations of 0.00 μg / mL, 0.05 μg / mL, 0.10 μg / mL, 0.50 μg / mL, 1.00 μg / mL, and 2.00 μg / mL, respectively, to prepare CPD calibration solutions.

[0262] A 5 M sodium chloride solution was prepared by dissolving 290 g NaCl (Fisher) in 1 L water. An ether-hexane solution was prepared by mixing 100 mL ether with 900 mL hexane.

[0263] Prepare the product by adding a 10g test portion of a rolled bath towel or paper towel (accurate to 0.01g) to a beaker. Add 100μL of the internal standard working solution. Add 5M NaCl solution to a total weight of 40g and mix into a homogeneous mixture by crushing any small pieces with a spatula. Place the product in an ultrasonic bath for 15 minutes. Cover the bath and soak the product for 12 to 15 hours. Place the EXTRAUT TMThe supplement pack (available from EM Science) was added to 20 g of the prepared product and mixed thoroughly with a spatula. The mixture was poured into a 40×2 cmid glass chromatography tube with a sintered disk and a tap. The test tube was briefly agitated by hand to compact the contents, then covered with a 1 cm layer of sodium sulfate (Fisher) and allowed to stand for 15 to 20 minutes. The non-polar contents were eluted with 80 mL of ether-hexane. Unrestricted flow was allowed except for the powder soup, the flow of which was limited to approximately 8 to 10 mL / min. The tap was closed when the solvent reached the sodium sulfate layer, and the collected solvent was discarded. The CPD was eluted with 250 mL of ether at a flow rate of approximately 8 mL / min. 250 mL of the eluate was collected in a 250 mL volumetric flask. 15 g of anhydrous sodium sulfate was added, and the flask was allowed to stand for 10 to 15 minutes.

[0264] The eluate was filtered through Whatman No. 4 filter paper into a 250 mL round-bottom or pear-shaped flask. The extract was concentrated to about 5 mL on a rotary evaporator at 35 ° C. The concentrated extract was transferred to a 10 mL volumetric flask with ether and diluted to scale with ether. A small amount (about the tip of a spatula) of anhydrous sodium sulfate was added to the flask and shaken, then left for 5 to 10 minutes. Using a 1 mL gas-tight injector, 1 mL of the extract was transferred to a 4 mL vial. The solution was evaporated to dryness below 30 ° C under a stream of nitrogen. 1 mL of 2,2,4-trimethylpentane and 0.05 mL of heptafluorobutyrylimidazole were immediately added and the vial was sealed. The vial was shaken with a Vortex shaker for a few seconds and heated at 70 ° C in a block heater for 20 minutes. The mixture was cooled to <40 ° C and 1 mL of distilled water was added. The mixture was shaken with a Vortex shaker for 30 seconds. The phases were separated and then shaken repeatedly. The 2,2,4-trimethylpentane phase was transferred to a 2 mL vial and a spatula tip amount of anhydrous sodium sulfate was added and shaken, then the vial was allowed to stand for 2 to 5 minutes. The solution was transferred to a new 2 mL vial for GC / MS. A parallel method blank containing 20 g of 5 M NaCl solution was performed for each batch test.

[0265] Calibration samples were prepared by adding to a set of 4 mL vials, 0.1 mL of each calibration solution, 10 μL of CPD internal working standard, and 0.9 mL of 2,2,4-trimethylpentane and derivatized as described above.

[0266] Calibration samples and product samples were analyzed on a gas chromatograph / mass spectrometer. The gas chromatograph was equipped with a split / splitless injector. The column was a nonpolar, 30 m × 0.25 mm, 0.25 mm film thickness (J&W Scientific) DB-5ms or equivalent column. The recommended temperature program was an initial temperature of 50 °C, held for 1 minute, ramped to 90 °C at 2 °C / min; ramped to 270 °C at a maximum rate; held for 10 minutes. The operating conditions were: injector temperature, 270 °C; transfer line temperature, 270 °C; carrier gas, He, 1 mL / min; and injection volume, 1.5 mL, splitless mode, splitless cycle, 40 s. The mass spectrometer was multiple ion monitoring or high sensitivity full scan. The conditions were positron ionization and selected ion monitoring of m / z 257 (internal standard), 453, 291, 289, 275 and 253 (CPD) or full scan in the range of 100 amu to 500 amu.

[0267] Measure the areas of the 3-CPD-d5 (m / z 257) and 3-CPD (m / z 253) derivative peaks. Calculate the ratio of the 3-CPD (m / z 253) derivative peak area to the 3-CPD-d5 (m / z 257) derivative peak area. Create a calibration graph for the standards by plotting the peak area ratio versus the weight of 3-CPD in each vial (in micrograms). Calculate the slope of the calibration line. 3-MCPD, mg / kg = (A×10) / (A'×C) test portion, g where MCPD = molecular CPD; A = peak area of ​​3-CPD derivative; A' = peak area of ​​3-CPD-d5 derivative; and C = slope of the calibration line. Use the same sample and standard preparation and analytical techniques to analyze DCPs (which have different retention time peaks and molecular weights on the mass spectrometer).

[0268] If CPD or DCP is detected without PAE being added to the wet end of the paper machine, determine if these chemicals are from the Yankee coating by removing the Yankee layer from both layers of a two-ply tissue, napkin, or face product using the Tape Layer Purity Test. Care must be taken to ensure that the surface contacting the Yankee surface is the surface being removed by the tape. Some tissue products may be reverse laminated, Yankee side in or Yankee side to Yankee side. After removing the Yankee layer, perform the above test method on the sample.

[0269] The DCP, CDP and PAE of commercially available tissue samples were measured. Fig. 9 As shown in Table 1.

[0270] Test method for the amount of GPAM / APAM complex in products

[0271] The following test method is used to determine the amount of GPAM / APAM complex in the final product: 1. Weigh the sample and record (3 to 4 sheets of paper towels, 6 to 7 sheets of tissue paper). 2. Place the sample in the Soxhlet Extraction Body. 3. Fill a 250 mL flat-bottom boiling flask (VWR Cat. No. 89000-330) about halfway with DI water. 4. Place the Soxhlet Extraction Body in the neck of the flat-bottom boiling flask. 5. Connect the assembled unit to the bottom of the hot water condenser so that the flat-bottom boiling flask is on the hot plate. 6. Wrap the assembled unit with two pieces of insulating cloth. 7. Turn on the hot plate to 400°C. 8. Turn on the cold water to the condenser until you see water flowing through the hose connected to the condenser and water flowing out of the drain of the sink. The flow should be steady, but not high. 9. Allow the extraction to run overnight. 10. The next day turn off the hot plate and remove the insulating cloth. Allow the assembled unit to cool to the touch. 11. Remove the assembled unit from the condenser. With the assembled unit still connected, rinse the Soxhlet extract with DI water from the DI water bottle. This is to ensure that all of the water used during the extraction method flows into the flat bottom flask. 12. Remove the Soxhlet extract from the flat bottom flask, ensuring that any residue in the extract can drain into the flat bottom flask. 13. Weigh a 250mL beaker and record its weight. Then take it to a fume hood. 14. Pour the contents of the flat bottom flask into the beaker. 15. Place the beaker on a hot plate set to 150°C and allow the water to evaporate. 16. When all of the water has evaporated and only the extract is left in the beaker, turn off the hot plate and allow the beaker to cool to room temperature. 17. Weigh the beaker plus extract and record it. 18. Subtract the weight of the beaker from the weight of the beaker plus extract to determine the weight of the extract. Finally, divide the weight of the extract by the original sample weight and multiply by 100 to get the % extract.

[0272] (See table below).

[0273]

[0274] For the following examples, UHMW GPAM copolymer (Hercobond TM Plus 555 dry strength additive) is produced by Solenis according to the methods described in U.S. Patent No. 7,875,676 B2 and U.S. Patent No. 9,879,381 B2, which are incorporated herein by reference in their entirety, and shipped to the manufacturing site at 2% solids to prevent chemical crosslinking. In order to reduce transportation costs and maintain maximum chemical efficiency, it is preferred to produce UHMW GPAM on site.

[0275] Example 3

[0276] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Peace River NBSK, available from Mercer, Suite 1120, 700 West Pender Street Vancouver, BC V6C 1G8 Canada) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 11.0 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TM Plus 555 dry strength additive, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 3.75 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. NBSK was refined separately on a conical refiner using 70 kwh / ton before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 5% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1 The tissue was stacked together using a steel embossed roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 156 sheets and a roll diameter of 148 mm, each sheet being 6.0 inches long and 11 inches wide was produced. The 2-ply tissue product had the following product attributes: Basis weight 43.3 g / m 2, thickness of 0.749 mm, MD tensile of 497 N / m, CD tensile of 480 N / m, ball burst of 1105 gf, MD stretch of 18.5%, CD stretch of 11.8%, CD wet tensile of 117.2 N / m, absorbency of 13.25 g / g, and TSA hand softness of 46.2, TS7 of 24.7, and TS750 of 36.4. PAE resin was not used in this example.

[0277] Comparative Example 4

[0278] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Peace River NBSK, available from Mercer, Suite 1120, 700 West Pender Street Vancouver, BC V6C 1G8 Canada) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 9.0 kg / metric ton (dry basis) of polyamine polyamide-epichlorohydrin resin (Kymene TM 1500LV wet strength resin, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533), and 3.75 kg / metric ton (dry basis) of high molecular weight anionic polyacrylamide (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. NBSK was refined separately on a conical refiner using 70 kwh / ton before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 5% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1The tissue was stacked together using a steel embossed roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product having 143 sheets and a roll diameter of 148 mm, each sheet having a length of 6.0 inches and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight of 40.0 g / m 2 , thickness 0.808 mm, MD tensile 334 N / m, CD tensile 343 N / m, ball burst 827 grams force, MD stretch 18.1%, CD stretch 11.1%, CD wet tensile 99.8 N / m, absorbency 15.8 g / g, and TSA hand softness 47.3, TS7 23.1, and TS750 37.1. The measured concentration of CPD in the product is 900 parts per billion, while the measured concentration of DCP is less than 50 parts per billion. Test method: LFGB paragraph 64, method B 80.56-2-2002-09, performed by GCMS. The aqueous extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraβe 3, 63741 Aschaffenburg, Germany) is the supplier who performed the test. PAE content is 0.165%. No reuse or regeneration of machine white water or ingredients.

[0279] Example 4

[0280] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 9.0 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TMPlus 555 dry strength additive, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 6% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1 The tissue was stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 164 sheets and a roll diameter of 148 mm, each sheet being 6.0 inches long and 11 inches wide was produced. The 2-ply tissue product had the following product attributes: Basis weight of 40.7 g / m 2 , thickness is 0.726mm, MD tensile is 476N / m, CD tensile is 421N / m, ball burst is 1055gf, MD stretch is 19.5%, CD stretch is 11.4%, CD wet tensile is 120.9N / m, absorbency is 12.58g / g, and TSA hand softness is 44.6, TS7 is 24.3, and TS750 is 47.3, wet scrubbing is 103 turns, wet thickness is 504μm / 2 layers, and wet ball burst is 342gf. The measured concentration of CPD in the product is less than 50 parts per billion, and the measured concentration of DCP is less than 50 parts per billion, test method: LFGB paragraph 64, method B 80.56-2-2002-09, by GCMS. The water extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraße 3, 63741 Aschaffenburg, Germany) was the supplier who performed the test. No machine white water or furnish was reused or regenerated. The PAE content was 0.02%. No adipic acid PAE was found in this sample, and only a small amount of glutaric acid PAE was detected, which is known to be added to Yankee coatings.

[0281] Example 5

[0282] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 11.0 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TM Plus 555 dry strength additive, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 6% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1 The tissue was stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 162 sheets and a roll diameter of 148 mm, each sheet having a length of 6.0 inches and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight of 41.6 g / m 2, thickness of 0.728 mm, MD tensile of 538 N / m, CD tensile of 490 N / m, ball burst of 1108 gf, MD stretch of 20.4%, CD stretch of 12.7%, CD wet tensile of 125.2 N / m, absorbency of 12.58 g / g, and TSA hand softness of 42.8, TS7 of 25.2, and TS750 of 54.0, wet scrubbing of 114 turns, wet thickness of 533 μm / 2 layer, and wet ball burst of 405 gf. PAE resin was not used in this embodiment.

[0283] Example 6

[0284] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 4.5 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TM Plus 555 dry strength additive, purchased from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533), 2.5 kg / metric ton (dry basis) of polyamine polyamide-epichlorohydrin resin (Kymene TM 1500LV wet strength resin, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of high molecular weight anionic polyacrylamide (Hercobond TM2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 6% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1 The tissue was stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 152 sheets and a roll diameter of 148 mm, each sheet having a length of 6.0 inches and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight of 40.6 g / m 2 , thickness is 0.754mm, MD tensile is 417N / m, CD tensile is 412N / m, ball burst is 1058gf, MD stretch is 18.5%, CD stretch is 11.9%, CD wet tensile is 112.2N / m, absorbency is 14.33g / g, and TSA hand softness is 45.4, TS7 is 23.7, and TS750 is 45.8, wet scrubbing is 95 turns, wet thickness is 534μm / 2 layer, and wet ball burst is 334gf. The measured concentration of CPD in the product is 500 parts per billion, and the measured concentration of DCP is 53 parts per billion, test method: LFGB paragraph 64, method B 80.56-2-2002-09, by GCMS. The water extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraβe 3, 63741 Aschaffenburg, Germany) was the supplier for the test. PAE was measured to be 0.054 wt%. The two layers of the product were extracted with hot water to give 0.036 g of complex and an extraction yield of 0.55%. No machine white water or ingredients were reused or regenerated.

[0285] Comparative Example 5

[0286] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 75% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 25% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 9.0 kg / metric ton (dry basis) of polyamine polyamide-epichlorohydrin resin (Kymene TM 1500LV wet strength resin, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1200 m / min, 6% slower than the forming section. In addition, the reel section ran 3% faster than the Yankee. The DEKO process described herein was then used using a Figure 1 The tissue was stacked together using a steel embossed roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 146 sheets and a roll diameter of 148 mm, each sheet being 6.0 inches long and 11 inches wide was produced. The 2-ply tissue product had the following product attributes: Basis weight of 41.4 g / m 2, thickness is 0.790mm, MD tensile is 436N / m, CD tensile is 360N / m, ball burst is 1031 grams, MD stretch is 18.0%, CD stretch is 11.2%, CD wet tensile is 105.2N / m, absorbency is 14.1g / g, and TSA hand softness is 49.0, TS7 is 22.8, and TS750 is 42.0, wet scrubbing is 95 turns, wet ball burst is 310.7 grams, and wet thickness is 600μm / 2 layer. The measured concentration of CPD in the product is 2375 parts per billion, and the measured concentration of DCP is 190 parts per billion, test method: LFGB paragraph 64, method B 80.56-2-2002-09, by GCMS. The aqueous extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (ZeppelinstraBe 3, 63741 Aschaffenburg, Germany) was the supplier who performed the tests. No machine white water or ingredients were reused or regenerated.

[0287] Comparative Example 6

[0288] The paper towel is made on a wet-laid product with a three-layer headbox using a through-air drying method. The TAD fabric development design was produced using the method of U.S. Patent No. 10,815,620, the contents of which are incorporated herein by reference in their entirety. The TAD fabric is a laminated composite fabric with a web contact layer made of an extruded thermoplastic polyurethane web, with 30 elements per inch in the longitudinal direction and 5 elements per inch in the transverse direction. The width of the longitudinal elements is about 0.26 mm, and the width of the transverse elements is 0.6 mm. The distance between the MD elements is about 0.60 mm, and the distance between the CD elements is 5.5 mm. The total pocket depth is equal to the thickness of the network, which is equal to 0.4 mm. The depth from the top surface of the network to the top surface of the CD element is 0.25 mm. The support layer has 56 yarns / inch of 0.27×0.22 mm cross-section rectangular MD yarns (or filaments) and 41 yarns / inch of 0.35 mm thickness CD yarns. The weave pattern of the base layer is 5-shed, with 1MD yarns above 4CD yarns, then below 1CD yarns, and then repeating. The material of the bottom fabric yarns is 100% PET. The composite fabric has an air permeability of about 450cfm. The flow rate of each layer of the headbox is about 33% of the entire paper. The three layers of the finished tissue are marked from top to bottom as air layer, core layer, and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue. All three layers of the tissue were made from 50% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 50% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 9.0 kg / metric ton (dry basis) of "G3" polyamine polyamide-epichlorohydrin resin (Kymene TM GHP20 wet strength resin, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of HMW APAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 71 kwh / tonne before blending into the layers. BEK was refined separately on a conical refiner using 20 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1000 m / min, 3% slower than the forming section. In addition, the reel section ran 10% slower than the Yankee. The DEKO process described herein was then used with Figure 1 The tissues were stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 228 sheets and a roll diameter of 148 mm, a length of 6.0 inches per sheet and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight 42 g / m 2 , thickness is 0.508mm, MD tensile is 407N / m, CD tensile is 486N / m, ball burst is 944gf, MD stretch is 20.2%, CD stretch is 11.0%, CD wet tensile is 129.9N / m, absorbency is 11.49g / g, and TSA hand softness is 51.5, TS7 is 21.7, and TS750 is 38.7, wet scrubbing is 49 turns, wet ball burst is 336.6gf, and wet thickness is 455.7μm / 2 layer. The measured concentration of CPD in the product is 148 parts per billion, and the measured concentration of DCP is less than 50 parts per billion, test method: LFGB paragraph 64, method B 80.56-2-2002-09, by GCMS. The water extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraße 3, 63741 Aschaffenburg, Germany) was the supplier for the tests. The PAE percentage was 0.12 wt%. No machine white water or furnish was reused or regenerated.

[0289] Comparative Example 7

[0290] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design with round weft yarns (0.65 mm) called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue are made from 70% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Phone: 1-901-419-6500) and 30% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Phone: +1-212-818-8244). 2.0 kg / metric ton (dry basis) of Fennorez 3000 (a GPAM copolymer from Kemira (Energiakatu 4 P.O. Box 33000101 Helsinki, Finland, Tel: +358108611, Fax: +358108621119)) and 2.0 kg / metric ton (dry basis) of APAM (Fennobond 85, purchased from Kemira) were added to each of the three layers to develop wet strength. For this embodiment, an exemplary polymeric aldehyde functionalized polymer can be a glyoxalated polyacrylamide, such as a cationic glyoxalated polyacrylamide or APAM, as described in U.S. Patents Nos. 3,556,932, 3,556,933, 4,605,702, 7,828,934 and U.S. Patent Application No. 2008 / 0308242, which are incorporated herein by reference. This compound contains FENNOBOND TM NBSK is a brand polymer from Kemira Chemicals of Helsinki, Finland. NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1350 m / min, 12% slower than the forming section. In addition, the reel section ran at the same speed as the Yankee. The DEKO process described herein was then used with Figure 1The tissues were stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 148 sheets and a roll diameter of 148 mm, a length of 6.0 inches per sheet and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight of 38.4 g / m 2 , thickness of 0.778 mm, MD tensile of 280 N / m, CD tensile of 302 N / m, ball burst of 708 gf, MD stretch of 14.6%, CD stretch of 8.6%, CD wet tensile of 57.3 N / m, absorbency of 14.15 g / g, and TSA hand softness of 46.8, TS7 of 22.5, and TS750 of 52.4, and D value of 2.4, wet scrubbing of 35 turns, wet thickness of 542 μm / 2 layers, and wet ball burst of 140 gf. No PAE resin was added.

[0291] Example 7

[0292] Paper towels are made on wet-laid products with a three-layer headbox using a ventilation drying method. A TAD fabric design with round weft yarns (0.65 mm) called AJ469 provided by AstenJohnson (4399Corporate Road, Charleston, SC 29405 USA, Tel: +1.843.747.7800) is used. The flow rate of each layer of the headbox is about 33% of the whole paper. The three layers of the finished tissue paper are marked from top to bottom as air layer, core layer and dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center part of the tissue paper. All three layers of the tissue were made from 70% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 30% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 6.3 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TM Plus 555 dry strength additive, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 2.1 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 0.3 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 60 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1350 m / min, 12% slower than the forming section. In addition, the reel section ran 2% slower than the Yankee. The DEKO process described herein was then used with Figure 1 The tissues were stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 143 sheets and a roll diameter of 148 mm, each sheet having a length of 6.0 inches and a width of 11 inches was produced. The 2-ply tissue product had the following product attributes: Basis weight of 40.8 g / m 2 , thickness is 0.840mm, MD tensile is 398N / m, CD tensile is 445N / m, ball burst is 1042gf, MD stretch is 18.0%, CD stretch is 9.3%, CD wet tensile is 105N / m, absorbency is 15.16g / g, and TSA hand softness is 41.9, TS7 is 27.3, and TS750 is 54.8, and D value is 2.2, wet scrubbing is 85 turns, wet thickness is 594μm / 2 layer, and wet ball burst is 266gf. The measured concentration of CPD in the product is less than 50 parts per billion, and the measured concentration of DCP is less than 50 parts per billion, test method: LFGB paragraph 64, method B80.56-2-2002-09, by GCMS. The water extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraße 3, 63741 Aschaffenburg, Germany) was the supplier who performed the test. No machine white water or furnish was reused or recycled. The PAE content was less than 0.02%. Adipic acid PAE was not detected in this sample. Only glutaric acid PAE was detected, which is known to be added to Yankee coatings. The hot water extraction yield of all three layers of the product was 0.038 g, and 0.57% of the complex was extracted.

[0293] Example 8

[0294] Tissue paper was made using a through-air drying process on a wet-laid product with a three-layer headbox. A laminated composite fabric with a polyurethane web described in U.S. Patent No. 10,815,620 was used, with an MD of 16 strands per inch x a CD of 14 strands per inch. The flow rate of each layer of the headbox was about 33% of the entire paper. The three layers of the finished tissue paper were labeled from top to bottom as the air layer, the core layer, and the dry layer. The air layer is the outer layer placed on the TAD fabric, the dry layer is the outer layer closest to the Yankee dryer surface, and the core layer is the center portion of the tissue paper. All three layers of the tissue were made from 70% NBSK (Grand Prairie NBSK, available from International Paper, 6400 Poplar Ave, Memphis, TN 38197, Tel: 1-901-419-6500) and 30% eucalyptus (Cenibra pulp, available from Itochu International 1251 Avenue of the Americas, New York, NY 10020, Tel: +1-212-818-8244). 9.0 kg / metric ton (dry basis) of UHMW GPVM adduct (Hercobond TM Plus 555 dry strength additive, available from Solenis 2475 Pinnacle Drive, Wilmington, DE 19803 USA, Tel: +1-866-337-1533) and 5.0 kg / metric ton (dry basis) of HMWAPAM (Hercobond TM 2800 dry strength additive, purchased from Solenis) was added to each of the three layers to develop wet strength. In addition, 1.5 kg / metric ton (dry basis) of a polyvinyl amine retention aid (Hercobond TM 6950 dry strength additive from Solenis). NBSK was refined separately on a conical refiner using 100 kwh / tonne before blending into the layers. The Yankee and TAD sections ran at 1000 m / min, 6% slower than the forming section. In addition, the reel section ran 14% slower than the Yankee. The DEKO process described herein was then used with Figure 1 The tissues were stacked together using a steel embossing roll with the pattern shown and a 7% polyvinyl alcohol based adhesive heated to 120°F. A roll of 2-ply product with 134 sheets and a roll diameter of 148 mm, each sheet being 6.0 inches long and 11 inches wide was produced. The 2-ply tissue product had the following product attributes: Basis weight 43.2 g / m 2, thickness is 0.908mm, MD tensile is 407N / m, CD tensile is 441N / m, ball burst is 1149gf, MD stretch is 25.4%, CD stretch is 13.1%, CD wet tensile is 125.6N / m, absorbency is 17.60g / g, and TSA hand softness is 38.3, TS7 is 33.9, and TS750 is 33.2, and D value is 2.2, wet scrubbing is 110 turns, and wet thickness is 610μm / 2 layer. Wet ball burst cannot be measured. The measured concentration of CPD in the product is less than 50 parts per billion, and the measured concentration of DCP is less than 50 parts per billion, test method: LFGB paragraph 64, method B 80.56-2-2002-09, performed by GCMS. The aqueous extract was prepared according to DIN EN 645:1994-01, 10 g paper per 250 mL cold water. ISEGA (Zeppelinstraße 3, 63741 Aschaffenburg, Germany) was the supplier for the tests. No machine white water or ingredients were reused or regenerated.

[0295] It is apparent from the above examples and comparative examples that the method according to an exemplary embodiment of the present invention obtains rolls of retail paper towels having very low DCP and MCPD, as well as super premium paper towel properties (fluff, absorbency, MD / CD dry strength and CD wet strength), with a very low dosage of PAE. As background, G3 PAE, which is a purified PAE (i.e., chlorine materials are removed before use in the factory), can be used to obtain a certain level of wet strength. However, purified PAE has a lower reactivity per molecule and lower wet strength properties. In addition, purer PAE is required to obtain high levels of wet strength, which is harmful to absorbency and the environment, and is expensive. In general, the use of G3 PAE results in paper towel products having low strength, low absorbency, and low fluffiness, and is more expensive.

[0296] As shown in Comparative Example 8, if the molecular weight of the GPAM / APAM complex is too low or the radius of gyration (ROG) of the complex (explained further below) is not optimal, the desired properties of the tissue product may not be achieved using the GPAM / APAM complex. In contrast, it is believed that according to an exemplary embodiment of the present invention, a very large molecular weight complex is used to form a "network" around the pulp fiber web, thereby holding the web together. Therefore, it is preferred to produce GPAM at 2% solids on site in the mill. In contrast, most GPAMs have a solids content >5% or close to 10%.

[0297] Without being bound by theory, an important aspect of the present invention involves the use of high MW GPAM / APAM complexes that remain anionic, as opposed to conventional techniques involving the use of cationic complexes. It is believed that the use of GPAM / APAM complexes that remain anionic creates more ionic or covalent bonds between the complex and the pulp fibers. This is contrary to the traditional view that cationic complexes need to be bound to anionic fibers (e.g., all virgin pulp fibers). Again, without being bound by theory, it is believed that charge is not the controlling factor and the number of connections in the network is equally or more important. Cationic GPAM / APAM complexes indicate that the GPAM charge exceeds that of APAM. The APAM polymer is consumed and may not expand to its maximum size. The use of anionic GPAM / APAM complexes will result in larger anionic sizes, which can be expressed as the ROG of the polymer. A larger ROG will create a larger network with the same number of molecules.

[0298] In the absence of a PVAM retention aid, the large anionic GPAM / APAM complex may not be retained at a high enough level. PVAM is very highly cationic. This high charge forces the GPAM / APAM complex to bind to pulp fibers which have an evenly distributed negative charge.

[0299] While detailed descriptions of specific embodiments of the present invention have been set forth in the foregoing specification, it will be appreciated that those skilled in the art could make considerable changes to many of the details set forth herein without departing from the spirit and scope of the present invention.

Claims

1. A paper or paperboard product comprising: lignocellulose and / or cellulose fibers; at least 0.05 wt. % of an ultra-high molecular weight glyoxalated poly(ethylene amide) (UHMW GPVM) adduct and a high molecular weight anionic poly(ethylene amide) (HMWAPAM) complex; Dichloropropane at a concentration below 50 ppb; 3-MCPD at concentrations below 300 ppb; and 0 to 0.09 wt% polyaminoamide-epihalohydrin; The product has a wet tensile strength of at least 10% of the dry tensile strength value.

2. The paper or paperboard product according to claim 1, in: (i) the product comprises 0.25 wt % to 1.5 wt % of the UHMW GPVM adduct and HMWAPAM complex; (ii) the wet tensile strength of the product is at least 15% of the dry tensile strength value of the product; or (iii) both (i) and (ii).

3. The paper or paperboard product of claim 1, wherein the UHMW GPVM adduct and HMWAPAM complex comprises: (i) HMWAPAM having a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons; (ii) UHMW GPVM having a weight average molecular weight (Mw) of greater than 2,000,000 Daltons to about 50,000,000 Daltons; or (iii) both (i) and (ii).

4. The paper or paperboard product according to claim 1, in: (i) the product does not contain polyaminoamide-epihalohydrin as measured using the "adipic acid test"; (ii) the wet tensile strength of the product is at least 20% of the dry tensile strength value of the product; or (iii) both (i) and (ii).

5. A paper or paperboard product comprising: 80 to 99 wt. % lignocellulosic and / or cellulose fibers; 0.05 wt % to 1.5 wt % of an ultra-high molecular weight glyoxalated poly(ethylene amide) (UHMW GPVM) adduct and a high molecular weight anionic poly(ethylene amide) (HMWAPAM) complex; and 0% to 0.5% by weight of polyvinylamine.

6. The paper or paperboard product according to claim 5, in: (i) the product comprises 0.25 wt % to 1.5 wt % of the UHMW GPVM adduct and HMWAPAM complex; (ii) the wet tensile strength of the product is at least 15% of the dry tensile strength value of the product; or (iii) both (i) and (ii).

7. The paper or paperboard product of claim 5, wherein the UHMW GPVM adduct and HMWAPAM complex comprises: (i) HMWAPAM having a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons; (ii) UHMW GPVM adduct having a weight average molecular weight (Mw) of greater than 2,000,000 Daltons to about 50,000,000 Daltons; or (iii) both (i) and (ii).

8. The paper or paperboard product of claim 5, wherein the UHMW GPVM adduct and HMWAPAM complex comprises: (i) HMWAPAM having a weight average molecular weight (Mw) of 550,000 Daltons to 1,500,000 Daltons; (ii) UHMW GPVM adduct having a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons; or (iii) both (i) and (ii).

9. The paper or paperboard product according to claim 5, wherein the UHMW GPVM adduct and HMWAPAM complex comprises HMWAPAM in a molar ratio of acrylic acid to acrylamide of 7:93 to 40:

60.

10. The paper or paperboard product according to claim 5, wherein the UHMW GPVM adduct and HMWAPAM complex comprises HMWAPAM in a molar ratio of acrylic acid to acrylamide of 12:88 to 35:

65.

11. The paper or paperboard product according to claim 10, wherein the product comprises 0.25 to 1.5 wt. % of the UHMW GPVM adduct and HMWAPAM complex.

12. The paper or paperboard product of claim 5, wherein the product exhibits a repulp time that is at least 20% less than a similar PAE resin treated paper or paperboard product having a comparable defibration level and substantially the same wet strength measured when fully wetted after a 2 hour aqueous soak.

13. The paper or paperboard product of claim 12, wherein during repulping in water having a pH of about 9 or greater, the product exhibits a repulping time that is at least 20% less than a similar PAE resin treated paper or paperboard product.

14. The paper or paperboard product according to claim 5, wherein the product comprises 0.01 to 0.5 wt. % of the polyvinylamine.

15. A method of making a paper or paperboard product, include: forming an aqueous raw material mixture comprising 80 wt % to 99 wt % solid lignocellulose and / or cellulose fibers, 0.05 wt % to 1.5 wt % solid ultra-high molecular weight glyoxalated polyvinylamide (UHMW GPVM) adduct and high molecular weight anionic polyacrylamide (HMWAPAM) complex, 0 wt % to 0.09 wt % solid polyaminoamide-epihalohydrin, and 0 wt % to 0.5 wt % solid polyvinylamine; and The aqueous raw material mixture is tableted and dried to obtain the product.

16. The method of claim 15, wherein the aqueous feed mixture is formed without the addition of polyaminoamide-epihalohydrin, and wherein the product is free of polyaminoamide-epihalohydrin as measured using the "adipic acid test".

17. The method of claim 15, wherein the UHMW GPVM adduct and HMWAPAM complex comprises: (i) HMWAPAM having a weight average molecular weight (Mw) of greater than 500,000 Daltons to 2,000,000 Daltons; (ii) UHMW GPVM adduct having a weight average molecular weight (Mw) of 8,000,000 Daltons to about 25,000,000 Daltons; or (iii) both (i) and (ii).

18. The method of claim 15, wherein the UHMW GPVM adduct and HMWAPAM complex comprises HMWAPAM having a molar ratio of acrylic acid to acrylamide of 7:93 to 40:

60.

19. The method of claim 15, wherein the aqueous feed mixture is formed from 0.01 wt% to 0.5 wt% solids of the polyvinylamine.

20. The method of claim 15, wherein the paper or paperboard product comprises: (i) a concentration of less than 50 ppb of dichloropropane and a concentration of less than 300 ppb of 3-MCPD; the paper or paperboard product has a wet tensile strength of at least 15% of the dry tensile strength value; or (iii), both of (i) and (ii).

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