Use of fast reverse cationic emulsion polymers with polyvinylamine as retention and drainage aids

Abstract

The present invention generally relates to methods and compositions for making tissue, paper or paperboard and for enhancing their retention and drainage. In particular, the present disclosure provides a method for enhancing retention and draining by adding a retention and drainage aid comprising a fast reversed phase cationic emulsion polyacrylamide (QIC-EPAM) and a polyvinylamine (PVAm) polymer. Manufacture of paper under these conditions provides improved retention, gravity drain rate, and DDA drain time without excessive flocculation, and allows for a significant reduction in PVAm dosage.

Description

Technical Field

[0001] This invention generally relates to methods and compositions for manufacturing facial tissues, paper, or paperboard, and for enhancing their retention and drainability. Specifically, this disclosure provides methods for enhancing retention and drainability by adding retention-enhancing and filter-enhancing agents comprising fast-reverse cationic emulsion polymers and polyethyleneamine polymers. Manufacturing paper under these conditions provides improved retention, gravity drain rate, and DDA drain time without excessive flocculation. Background Technology

[0002] Recycled fiber materials, such as old corrugated cardboard (OCC), mixed office waste (MOW), and old magazines (OMG), are commonly used as raw materials for paper and paperboard such as recycled linerboard. The pulp quality of recycled paper is inferior in terms of fiber strength, and the recycled fibers contain a high content of fine powder and mineral fillers, which negatively impacts retention, draining, and dryer steam consumption during the recycled linerboard manufacturing process.

[0003] During paper or paperboard production, a diluted aqueous composition, referred to as "pulp" or "raw material," is sprayed onto a moving wire called "wire" or "wire screen." The solid components of this composition (such as cellulose fibers, fine powders, and inorganic particulate mineral fillers) are captured or filtered by the wire to form sheets. The percentage of solid material retained on the wire is called the "retention rate" in the papermaking process. Retention aids are used to improve the capture efficiency of solid components on the wire, thereby reducing the total suspended solids in the filtrate.

[0004] During sheet forming, the liquid component (i.e., filtrate) is removed by gravity dripping through a wire. The sheet is then subjected to further dewatering steps, such as vacuum dewatering, followed by press dewatering. "Dripping" is related to the rate at which water is removed from the pulp during paper formation. Dripping generally refers to water removal primarily occurring in the "drip zone" of the paper machine (e.g., gravity and vacuum dripping sections) before any pressing of the wet paper web. Filter aids are used to improve overall dewatering efficiency in paper or paperboard production.

[0005] After dehydration, the sheets undergo drying to remove residual water. Common drying methods include steam cylinders and air dryers. Effective dehydration during the preceding steps (e.g., using filter aids) allows for reduced steam and energy consumption during the drying process.

[0006] Retention and filter aids used in papermaking are typically added to the pulp or feedstock before being added to the headbox of the paper machine. Their purpose is to provide enhanced on-machine retention and dripping, while also offering additional benefits such as improved paper strength and wet pressing properties. These requirements are particularly challenging for papermaking operations in mills with high recycling content. Typical retention and filter aids include high molecular weight cationic polymers or CPAM / silica retention programs. When added to recycled fibers, these additives create large flocculations in the recycled pulp (i.e., over-flocculation), resulting in less uniform recycled paper and poor forming. Poorly formed sheets containing large fiber flocculations will exhibit high gravity dripping rates and will drip rapidly in the initial hydrofoil section of the paper machine. However, this over-flocculated sheet responds poorly to vacuum in later sections of the forming section, leading to reduced vacuum dripping (press dewatering) rates. The sheet will also require increased dryer steam consumption due to the increased water trapped in the large flocculations.

[0007] Significant efforts have been made to develop improved retention and filter aids. PCT / US99 / 29135 discloses a polyampholyte coagulant used as a retention aid / filter aid / forming aid in papermaking processes. However, commercially available retention and filter aids remain insufficient for manufacturing paper and paperboard with a high percentage of recycled fiber content.

[0008] Polyvinylamine (PVAM) polymers are widely used to improve vacuum draining and press dewatering rates in recycling paper machines, and reduce dryer steam consumption without affecting sheet formation. PVAM contains high cationic charge density and low molecular weight, and is an effective coagulant for capturing anionicly charged fibers, fine powders, and fillers. PVAM polymers typically produce small fiber flocs, and the size of these flocs does not increase with increasing PVAM dosage. Therefore, PVAM polymers are widely used to improve vacuum draining and press dewatering rates in recycling paper machines, and reduce dryer steam consumption without affecting sheet formation. However, PVAM polymers are very expensive, and many recycling linerboard mills cannot afford to use PVAM as a filter aid.

[0009] Based on the foregoing, there is a need for improved additives to enhance retention and draining without causing excessive fiber flocculation when used in the manufacture of paper, facial tissues, paper towels, and / or paperboard from recycled materials. Retention aids and filter aids are also needed, which significantly reduce the use of PVAm in recycled pulping. Therefore, the object of this invention is to provide methods and compositions (i.e., retention aids and filter aids) for enhancing retention and draining to provide improved retention and draining time while avoiding excessive flocculation and reducing the amount of PVAm added. This invention achieves these objectives as described herein by using a retention aid and filter aid process comprising a fast reverse-phase cationic polymer (QIC-EPAM) and PVAm. Summary of the Invention

[0010] This invention generally relates to methods and compositions for manufacturing facial tissues, paper, or paperboard, and for enhancing their retention and drainability. Specifically, this disclosure provides methods for enhancing retention and drainability by adding retention-enhancing and filter-enhancing agents comprising fast reverse cationic emulsion polyacrylamide (QIC-EPAM) and polyethyleneamine (PVAm) polymers. Manufacturing paper under these conditions provides improved retention, gravity drain rate, and DDA drain time without excessive flocculation and allows for a significant reduction in PVAm dosage.

[0011] On one hand, the present invention provides a method for manufacturing facial tissues, paper, or paperboard, the method comprising:

[0012] (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers.

[0013] (b) Optionally dilute the concentrated slurry to form a thinner slurry;

[0014] (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and

[0015] (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard;

[0016] The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising:

[0017] (i) one or more polyethyleneamine (PVAm) polymers; and

[0018] (ii) One or more fast reversed cationic emulsion polyacrylamides (QIC-EPAM), said QIC-EPAM comprising acrylamide (AM) monomer and cationic acryloyloxyethyltrimethylammonium chloride (Q9).

[0019] In some exemplary embodiments of the method, the one or more PVAm polymers and the one or more QIC-EPAMs:

[0020] (a) Premix before adding to the slurry;

[0021] (b) Premix before adding to the slurry;

[0022] (c) Added separately to the concentrated slurry;

[0023] (d) Added separately to the slurry;

[0024] (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or

[0025] (f) Added separately, wherein one or more PVAm polymers are added to the slurry and one or more QIC-EPAMs are added to the concentrate;

[0026] The time following steps (a)-(f) is optionally a mixed time ranging from 0.01 to 10 minutes, 0.1 to 5 minutes, or 1 to 2 minutes.

[0027] In some exemplary embodiments of the method, the one or more PVAm polymers:

[0028] (a) Includes weight-average molecular weights in the range of 50-3000 kDa, 100-2000 kDa, 200-2000 kDa or 400-800 kDa;

[0029] (b) The cation charge density contained as a dry solid at pH 7 in the range of less than 5.0 mEq / g, 0.5–5.0 mEq / g, 1.0–4.0 mEq / g, or 1.5–2.5 mEq / g;

[0030] (c) A polymer synthesized by Hofmann degradation of a base polymer comprising (i) acrylamide; (ii) methacrylamide; (iii) a copolymer of acrylamide and a cationic monomer selected from the group consisting of: dimethylaminoethyl acrylate (DMAEA), quaternized dimethylaminoethyl methacrylate (DMAEMA), dimethyl diallyl ammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC); or (iv) a copolymer of acrylamide and DADMAC;

[0031] (d) A polymer comprising a polymer synthesized by complete or partial hydrolysis of one or more poly(N-vinylformamide) homopolymers or copolymers, wherein the one or more poly(N-vinylformamide) homopolymers or copolymers are optionally synthesized by free radical polymerization of N-vinylformamide or by free radical polymerization of N-vinylformamide and one or more other monomers, and further comprising a degree of hydrolysis in the range of 1-100 mol%, 20-100 mol%, 40-100 mol%, 60-100 mol%, or 80-100 mol%.

[0032] (e) A polymer synthesized by partial hydrolysis of one or more poly(N-vinylformamide) homopolymers, and further comprising a degree of hydrolysis ranging from 30 to 50 mol%, 35 to 45 mol%, or about 40 mol%;

[0033] (f) Optionally formulated as a dry powder or as an aqueous composition, said aqueous composition comprising, by weight, from about 0.5% to about 30%, optionally more than 2% to about 25%, and more preferably more than about 10% to about 22% PVAm solids; or

[0034] Any combination of (g)(a)-(f).

[0035] In some exemplary embodiments of the method, the one or more rapid reversed cationic emulsion polyacrylamide (QIC-EPAM) are:

[0036] (a) Contains a range of 60-85 wt%, 65-85 wt%, 70-85 wt%, or 70-80 wt% of acrylamide (AM) monomer;

[0037] (b) Contains ≤40wt%, 15-40wt%, 15-35wt%, 15-30wt%, or 20-30wt% cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content; or

[0038] (c) Contains an inverted emulsion, a dry polymer, or an aqueous solution of a polymer, preferably an inverted emulsion;

[0039] (d) Polymer standard viscosity (SV) including ranges of less than or equal to 3.5 cPs, 2.0-3.5, 2.5-3.5 cPs, or 3.0-3.5 cPs; or

[0040] (e) Any combination of the foregoing terms.

[0041] In some exemplary embodiments of the method, the retention aid and filter aid optionally further comprises one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles, wherein:

[0042] (a) The further cationic dry polyacrylamide (DPAM) comprises an acrylamide (AM) monomer and one or more cationic monomers, wherein the one or more cationic monomers are selected from the group consisting of: acryloyloxyethyltrimethylammonium chloride (“AETAC”), methacryloyloxyethyltrimethylammonium chloride (“MAETAC”), methacrylamidepropyltrimethylammonium chloride (“MAPTAC”), acrylamidepropyltrimethylammonium chloride (“APTAC”), methacryloyloxyethyldimethylammonium sulfate, diallyldimethylammonium chloride (“DADMAC”); dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates and their quaternary ammonium salts or acid salts, including but not limited to: dimethylaminoethyl acrylate (“DMAEA”), dimethylaminoethyl methacrylate (“DMAEA”), dimethylaminoethyl acrylate methyl chloride quaternary ammonium salt, dimethylaminoethyl acrylate methyl sulfate quaternary ammonium salt, dimethylaminoethyl acrylate benzyl chloride quaternary ammonium salt, dimethylaminoethyl acrylate sulfate, dimethylaminoethyl acrylate hydrochloride, diethylaminoethyl acrylate methyl chloride quaternary ammonium salt, Dimethylaminoethyl methacrylate methyl chloride quaternary ammonium salt, dimethylaminoethyl methacrylate methyl sulfate quaternary ammonium salt, dimethylaminoethyl methacrylate benzyl chloride quaternary ammonium salt, dimethylaminoethyl methacrylate sulfate, dimethylaminoethyl methacrylate hydrochloride, methacryloyldimethylaminoethyl methacrylate hydrochloride; dialkylaminoalkylacrylamides and methacrylamides and their quaternary ammonium salts or acid salts, including but not limited to acrylamide propyltrimethylammonium chloride, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyltrimethylammonium chloride ... Diallyl dimethylaminopropylacrylamide sulfate, dimethylaminopropylacrylamide hydrochloride, methacrylamide propyltrimethylammonium chloride, dimethylaminopropylmethacrylamide, dimethylaminopropylmethacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylmethacrylamide sulfate, dimethylaminopropylmethacrylamide hydrochloride, diethylaminoethyl acrylate, diethylaminoethyl methacrylate; and diallyl dialkylammonium halides, including but not limited to diallyl diethylammonium chloride and diallyl dimethylammonium chloride (“DADMAC”), and any combination thereof; and

[0043] (b) The one or more inorganic microparticles are selected from the group consisting of microparticles and nanoparticles including: silica microparticles; colloidal silica; layered aluminum silicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite.

[0044] In some exemplary embodiments, the method includes one or more of the following:

[0045] (a) The one or more fast reverse cationic emulsion polyacrylamide (QIC-EPAM) comprises an acrylamide (AM) monomer content ranging from 70-80 wt% and a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; comprises a reverse emulsion; and comprises a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs.

[0046] (b) The one or more PVAm polymers have a weight-average molecular weight in the range of 400-800 kDa; or

[0047] (c) The one or more inorganic particles comprise bentonite, sodium bentonite or calcium bentonite.

[0048] In some exemplary embodiments of the method, when added to the thick slurry and / or the thin slurry:

[0049] (a) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1;

[0050] (b) The one or more PVAm polymers are added at a dosage ranging from 0.2-12 kg / t, 0.2-10 kg / t, 0.2-8 kg / t, 0.2-6 kg / t, 0.2-2 kg / t or 0.2-0.6 kg / t;

[0051] (c) The one or more QIC-EPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.1-0.2 kg / t;

[0052] (d) The one or more DPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.2-0.4 kg / t;

[0053] (e) The one or more inorganic microparticles are added at a dosage ranging from 0.1-4 kg / t, 1-4 kg / t, or 2-4 kg / t; or

[0054] Any combination of (f)(a)-(e).

[0055] In some exemplary embodiments, the method includes one or more of the following:

[0056] (a) The slurry has a consistency ranging from 1-5%, 1-3%, or 1-1.5%, where consistency refers to the weight percentage of total suspended solids in the aqueous slurry.

[0057] (b) The slurry has a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%;

[0058] (c) Diluting the concentrated slurry by adding water, chemical water, synthetic water, white water, and / or process water to form the thin slurry; or

[0059] (d) The concentrated pulp and / or the thin pulp optionally further comprise one or more papermaking-related additives, including but not limited to starch, dyes, bleaching agents, sizing agents, wet strength agents, dry strength agents, or anti-sticking agents; or

[0060] Any combination of (e), (a), and (c).

[0061] In some exemplary embodiments of the method, the aqueous suspension of cellulose fibers contains a pH in the range of 4-8, 4-7.5, 4-7, 4.5-7, or 5-7, and further comprises:

[0062] (a) A certain percentage of recycled cellulose fibers, ranging from 40-100% by weight, 50-100% by weight, 60-100% by weight, 80-100% by weight, or 90-100% by weight of recycled cellulose fibers.

[0063] (b) A combination of one or more recycled fibers, said one or more recycled fibers optionally obtained from sources including, but not limited to, used corrugated cardboard (OCC), mixed office waste (MOW), mixed office paper, old newspaper pulp (ONP), old magazines (OMG), factory waste paper fibers, or coated waste paper.

[0064] (c) Optional softwood fiber, hardwood fiber, refined fiber, non-wood fiber including but not limited to wheat straw pulp, and mixtures of any of the foregoing;

[0065] (d) Optionally, the pulp is selected from the following: kraft pulp, unbleached kraft pulp, bleached pulp, unbleached pulp, process water from pulp, paper and / or paperboard production, neutral sulfite semi-chemical (NSSC) pulp, mechanical pulp, non-wood pulp, and mixtures of any of the foregoing; or

[0066] (e) A certain amount of fine pulp powder and / or a certain amount of mineral filler, ranging from 5-30% by mass of the total solids in the aqueous suspension, wherein the certain amount of fine pulp powder comprises pulp particles small enough to pass through pores with a diameter of 76 µm, and the certain amount of mineral filler comprises calcium carbonate, clay, kaolinite, aluminum silicate, talc, and / or gypsum; or

[0067] (f) and the combination of (a)-(e).

[0068] In some exemplary embodiments of the method, when used to manufacture facial tissues, paper, or paperboard, the method causes the following when compared to the same method performed without (i) the addition of one or more PVAm or (ii) the addition of one or more QIC-EPAM:

[0069] (a) Increased retention of cellulose fibers;

[0070] (b) Increased retention of pulp fines and / or mineral fillers;

[0071] (c) The draining rate is faster on the wire mesh screen;

[0072] (d) The rate of pressing and dehydration increases;

[0073] (e) Reduced steam consumption in the dryer;

[0074] (f) Improvements in the quality of facial tissues, paper, or paperboard, such as those determined by a reduction in permeability;

[0075] (g) Reduced PVAm dose;

[0076] (h) The combination of QIC-EPAM and PVAm synergistically improves the paper machine's draining rate;

[0077] (i) The combination of QIC-EPAM and PVAm synergistically increases Canadian standard free radical (CSF); or

[0078] Any combination of (j)(a)-(i).

[0079] On the other hand, the present invention provides a method for manufacturing facial tissues, paper, boxboard, or paperboard, the method comprising:

[0080] (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers.

[0081] (b) Optionally dilute the concentrated slurry to form a thinner slurry;

[0082] (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and

[0083] (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard;

[0084] The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising:

[0085] (i) One or more polyvinylamine (PVAm) polymers;

[0086] (ii) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0087] (iii) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite.

[0088] In some exemplary embodiments of the method, the one or more PVAm polymers and the one or more QIC-EPAMs:

[0089] (a) Premix before adding to the slurry;

[0090] (b) Premix before adding to the slurry;

[0091] (c) Added separately to the concentrated slurry;

[0092] (d) Added separately to the slurry;

[0093] (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or

[0094] (f) Added separately, wherein one or more PVAm polymers are added to the slurry and one or more QIC-EPAMs are added to the concentrate.

[0095] On the other hand, the present invention provides a slurry comprising an aqueous suspension having a consistency ranging from 1-5%, 1-3%, or 1-1.5%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising:

[0096] (a) One or more polyethyleneamine (PVAm) polymers;

[0097] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0098] (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite;

[0099] in

[0100] (i) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1;

[0101] (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry;

[0102] (iii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

[0103] On the other hand, the present invention provides a slurry comprising an aqueous suspension having a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising:

[0104] (a) One or more polyethyleneamine (PVAm) polymers;

[0105] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0106] (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite;

[0107] in

[0108] (i) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry;

[0109] (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

[0110] On the other hand, the present invention provides a composition for use as a retention aid and filter aid in the manufacture of facial tissues, paper, or paperboard, the composition comprising:

[0111] (a) One or more polyethyleneamine (PVAm) polymers;

[0112] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0113] (c) Optionally one or more anionic organic or inorganic microparticles, said one or more anionic organic or inorganic microparticles being selected from the group consisting of microparticles and nanoparticles of the following: silica microparticles; colloidal silica; layered aluminosilicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite; and anionic polymer microparticles, including but not limited to highly structured anionic polyacrylamide. Attached Figure Description

[0114] The present invention will now be described in more detail with reference to the accompanying drawings.

[0115] Figure 1 Exemplary graphs are provided to show the DDA draining time gain % relative to blank and the DDA permeability gain % relative to blank of recycled liner paper manufactured from OCC pulp treated with PVAm and QIC-EPAM, according to Example 2.

[0116] Figure 2 Exemplary graphs are provided to show the DDA draining time gain % relative to blank and DDA filtrate turbidity (NTU) of recycled liner paper manufactured from OCC pulp treated with PVAm and QIC-EPAM, according to Example 3.

[0117] Figure 3Exemplary graphs are provided to illustrate the gravity water retention of recycled liner paper manufactured from 100% OCC pulp treated with PVAm and QIC-EPAM, as determined by the Canadian Standard Freeness (CSF) test, according to Example 4.

[0118] Figure 4 Exemplary graphs are provided to illustrate the DDA draining time of recycled liner paper manufactured from OCC pulp treated with PVAm and QIC-EPAM, according to Example 4. Detailed Implementation

[0119] Before describing the present invention, the following definitions are provided. Unless otherwise stated, all terms should be interpreted in accordance with the understanding of those skilled in the art.

[0120] definition

[0121] As used herein, the singular forms “a”, “and”, and “the” include the plural reference unless the context clearly specifies otherwise.

[0122] As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” may mean “one,” but also include plural referents such as “one or more” and “at least one.” Unless otherwise expressly stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0123] As used herein, the term “or” in the claims is used to mean “and / or” unless it is explicitly stated that it refers only to alternatives or that alternatives are mutually exclusive, but this disclosure supports the definition of “and / or” as referring only to alternatives.

[0124] As used herein, unless otherwise stated, the term "or combinations thereof" as used herein refers to all permutations and combinations of the items listed preceding the term.

[0125] papermaking

[0126] As used herein, the term "paper" includes articles comprising cellulose sheet materials, including paper, paperboard, etc.

[0127] As used herein, the terms “papermaking process” and “papermaking application” generally refer to any process capable of producing paper and / or paperboard articles of any form. Such processes include, for example, the manufacture of paper articles from pulp, including methods comprising forming an aqueous cellulose papermaking pulp, draining the pulp to form paper, and drying the paper. The steps of forming the papermaking pulp, draining, and drying can be performed in any conventional manner known in the art.

[0128] As used herein, the term "wet end of the paper machine" or "wet end" generally refers to the portion of the papermaking process between pulping (or bleaching) and wet pressing.

[0129] As used in this article, the term "fiber" refers to the basic structural unit of paper or paperboard.

[0130] As used herein, the terms “recycled fiber” and “reclaimed fiber” refer to paper, paperboard, and fiber waste from retail stores, office buildings, residences, manufacturing plants, etc., after they have been used as consumer products. Manufacturing waste includes: dry paper and paperboard waste generated after the completion of papermaking processes, such as envelope scraps, binding scraps, and other paper and paperboard waste generated from printing, cutting, forming, and other processing operations; bag, box, and carton manufacturing waste; factory packaging paper and unused raw materials; and finished paper and paperboard repulped from obsolete stockpiles of paper and paperboard manufacturers, merchants, wholesalers, distributors, printers, processors, or other parties. Specifically, the term “recycled fiber” includes recycled fibers obtained through processing paper and other consumer cellulosic materials, such as paper, old corrugated cardboard (OCC), mixed office waste (MOW), old magazines (OMG), unbleached kraft pulp, neutral sulfite semi-chemical (NCCS) pulp, and / or mechanical pulp. Raw materials for recycled fibers can be selected from used corrugated cardboard, mixed office waste, used newsprint, used magazines, double-lined kraft paper, and any mixture thereof. Mixed waste (MXW) refers to a recycled mixture of recycled cardboard (such as OCC, white cardboard, and / or folding linerboard) and recycled paper (such as used newsprint, used magazines, and / or office waste). Mixed office waste refers to recycled fiber materials primarily composed of copy paper, printer paper, and offset paper. Double-lined kraft paper refers to recycled fiber materials containing clean, sorted, unprinted corrugated cardboard boxes, cartons, paper, or scraps (e.g., kraft paper or jute liner). White cardboard (WLC) refers to multi-layer cardboard containing deinked fiber materials and / or undeinked recycled fiber materials in one or more layers, derived from, for example, OCC, mixed office waste, or used newspapers (ONP). The presence of any of these recycled fiber materials in the fiber suspension typically reduces the strength of the drained paper and provides the method with a significant amount of starch, hydrophobic, and colloidal substances.

[0131] As used herein, the term "OCC" refers to recycled corrugated cardboard and / or boxboard. Corrugated boxes are those made of three separate layers of paper, two layers of linerboard, and a corrugated or wave-shaped layer sandwiched between them. Brown paper bags are typically accepted for OCC for recycling. The term OCC indicates recycled fiber material with linerboards such as test linerboard, jute, or kraft paper, and may also include double-sorted corrugated boxboard (DS OCC).

[0132] As used herein, the term "waste paper" or "factory waste paper" refers to paper that becomes only suitable for repulping during the papermaking process, such as scraps or non-standard paper. Waste paper is reused material that never leaves the factory and is not considered for recycling or recovery. Waste paper is a valuable source of fiber that can be recycled within the factory.

[0133] As used herein, the term "coated waste paper" refers to waste paper containing coatings applied to the base paper during the papermaking process. When waste paper contains these coatings, particular problems arise in recycling to restore fiber value because these coatings introduce materials that are not typically present in the original fiber raw material used to manufacture the base paper. Coated waste paper may also contain dyes and / or other additives. In this application, coated waste paper includes surface-sized, dyed, and / or creased waste paper.

[0134] As used herein, the term “recycled fiber composition” generally refers to a composition comprising recycled cellulose fibers, typically a composition in which most or all of the fibers are recycled fibers, for example at least 20%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%.

[0135] As used herein, the term "fiber suspension" should be understood as an aqueous suspension comprising fibers (preferably recycled fibers) and optionally fillers. For example, a fiber suspension may contain at least 5%, preferably 10%-30%, more preferably 11%-19% mineral fillers. The mineral fillers may be any fillers conventionally used in paper and paperboard manufacturing, such as milled calcium carbonate, precipitated calcium carbonate, clay, talc, gypsum, titanium dioxide, synthetic silicates, aluminum trihydrate, barium sulfate, magnesium oxide, or any mixture thereof.

[0136] As used herein, the term "headbox" refers to a container in a paper machine that holds suspended aqueous cellulose solids and regulates their flow on wires or screens to drain them.

[0137] As used herein, the term "lignocellulose matrix" refers to paper and / or paperboard articles formed from plant dry matter (virgin or recycled) of any origin, which can be coated, printed, and / or formed into packaging articles. For example, such matrices include paper articles made from pulp, such as by methods comprising forming an aqueous cellulose pulping compound, draining the pulping compound to form sheets, and drying the sheets. The steps of forming the pulping compound, draining, and drying can be performed in any conventional manner known in the art. The matrix may contain polymeric reinforcing agents, such as wet strength agents and dry strength agents.

[0138] As used herein, the term "pulp" generally refers to a mixture of water, dissolved pulp, and optionally other soluble or insoluble components that are produced or added during the raw material manufacturing stage of papermaking.

[0139] As used herein, the term “pulp formulation” or “paper pulp formulation” generally refers to a mixture of cellulose fibers, pulp, optional fillers, dyes and water used to make paper or paperboard.

[0140] As used herein, the term "thick pulp" generally refers to a mixture of paper pulp and other materials with a consistency of about 1% to 5%.

[0141] As used herein, the term "slurry" generally refers to a mixture of paper pulp and other materials in a sector pump after it has been diluted with white water or other process water to a consistency of less than 1%.

[0142] As used in this article, the term "white water" generally refers to the process water within a papermaking machine system, particularly the water that is drained from the paper during the papermaking process.

[0143] As used herein, the term “fixed” means that a substance is at least temporarily or permanently bound or attached to a fiber.

[0144] As used herein, the term “flocculation” generally refers to the tendency of fibers to aggregate into bundles in the presence of retention aids, especially when in motion; the term also refers to the behavior of high-quality polymers forming bridges between suspended colloidal particles, resulting in strong, relatively irreversible aggregation.

[0145] The term "flocculator" generally refers to an agent that can bridge, neutralize, or promote the agglomeration of particles into larger aggregates, typically resulting in more efficient sedimentation. Flocculation processes typically involve adding a flocculant and then mixing it to promote collisions between particles, causing unstable particles to aggregate into larger particles, which can then be removed by gravity settling or by other means such as centrifugation or filtration.

[0146] As used herein, the "molecular weight, MW" of a polymer refers to the sum of the atomic weights of the individual atoms comprising the polymer molecule. It represents the average length of the bulk resin polymer chain. Not all polymer molecules of a particular grade have exactly the same molecular weight. Molecular weights exist within a range or distribution. Molecular weight can be measured using various methods known to those skilled in the art. For example, weight-average molecular weight can be measured using gel permeation chromatography (GPC). Alternatively, polymer molecular weight can be measured using a GPC / light scattering / viscosity assay (also known as triple-detection GPC), which employs a refractive index detector (with or without a UV detector), dilute solution viscosity assay, and light scattering in series to determine molecular weight, distribution, and related solution parameters.

[0147] Retention aids and filter aids

[0148] As used herein, the terms “polymer” or “polymer additive” and similar terms are used in their ordinary meaning as understood by those skilled in the art, and are therefore used herein to refer to or describe macromolecules (or groups of such molecules) that may contain repeating units. Polymers can be formed in a variety of ways, including by polymerizing monomers and / or by chemically modifying one or more repeating units of a precursor polymer. Unless otherwise stated, polymers may comprise “homopolymers” that may contain substantially the same repeating units, which can be formed, for example, by polymerizing a particular monomer. Unless otherwise stated, polymers may also comprise “copolymers” that may contain two or more different repeating units, which can be formed, for example, by copolymerizing two or more different monomers and / or by chemically modifying one or more repeating units of a precursor polymer. Unless otherwise stated, polymers or copolymers may also comprise “terpolymers” or “quaternary copolymers,” which generally refer to polymers containing three, four, or more different repeating monomer units. As used herein, the term “polymer” is intended to include both the acidic form of the polymer and its various salts. Polymers can be inherently amphoteric, that is, containing both anionic and cationic substituents, but not necessarily in equal proportions.

[0149] As used herein, the term "polyacrylamide" or "PAM" generally refers to polymers and copolymers containing an acrylamide moiety, and the term covers any polymer or copolymer (including terpolymers) containing an acrylamide moiety, such as one or more acrylamide polymers (copolymers) and additional monomers capable of copolymerizing with acrylamide. Furthermore, PAM may comprise any of the polymers or copolymers discussed herein. Additionally, the PAM described herein, such as one or more acrylamide polymers (copolymers), can be produced in a variety of forms, including, for example, dry (powder) forms (e.g., DPAM), emulsion polyacrylamide (EPAM), or liquid polyacrylamide. Amphoteric polyacrylamide (AmPAM) can be formulated in dry (powder) forms (e.g., AmDPAM) or emulsion forms (AmEPAM).

[0150] As used herein, the term "emulsion polymer" generally refers to a reverse emulsion (water-in-oil), in which water droplets containing the polymer are suspended in an oil phase (also known as a hydrophobic phase).

[0151] As used herein, the term "inverse emulsion" refers to a liquid polymer composition in which a polymer dissolved in an aqueous solution is dispersed in an oil phase (e.g., a hydrophobic liquid) to form an oil continuous phase, and then the oil continuous phase is mixed with the aqueous solution such that the dispersed polymer phase of the liquid polymer composition becomes a substantially aqueous continuous phase, and the hydrophobic liquid phase becomes a dispersed discontinuous phase. The conversion point can be characterized as the point at which the viscosity of the polymer solution substantially reaches its maximum value under a given set of conditions. In practice, this can be determined, for example, by periodically measuring the viscosity of the composition over time, and the solution is considered to have been converted when three consecutive measurements are within a criterion of measurement error.

[0152] As used herein, the term "liquid polymer" refers to a combination of at least one polymer and a liquid (typically an aqueous liquid). The polymer may be a completely dissolved or partially dissolved suspension, dispersion, or slurry. A "waterborne polymer mixture" or "hydrated polymer composition" refers to a combination of at least one polymer and an aqueous liquid. When a dry polymer is combined with an aqueous liquid, the polymer is initially partially hydrated at the polymer-water interface. The polymer does not immediately dissolve in the aqueous or non-aqueous solvent. Dissolution is controlled by the unwinding of the polymer chains or by diffusion of the chains through the boundary layer near the polymer-solvent interface. Upon thorough mixing, the polymer may become fully hydrated, at which point the wetting process is complete and the polymer may partially or completely dissolve, depending on the nature and composition of the polymer and solvent.

[0153] The term "water-soluble polymer" generally refers to any polymer that can be dissolved and / or dispersed in water. The polymer can alter the physical properties of aqueous systems undergoing gelation, thickening, viscousening, or emulsification / stabilization. The polymer can perform a variety of functions, including but not limited to use as a dispersant and suspending agent, stabilizer, thickener, viscous agent, gelling agent, flocculant and coagulant accelerator, film-forming agent, humectant, adhesive, and lubricant.

[0154] As used herein, the term "monomer" generally refers to nonionic monomers, anionic monomers, cationic monomers, zwitterionic monomers, betaine monomers, and zwitterionic-pair monomers.

[0155] As used here, "Q9 monomer" refers to 2-(acryloyloxy)ethyl]trimethylammonium chloride (Q9), which has the molecular formula C8H16ClNO2 and a molecular weight of 193.67 g / mol.

[0156] As used herein, acrylamide or "AM" refers to a neutral monomer with the molecular formula C3H5NO and a molecular weight of 71.08 g / mol.

[0157] As used herein, the term "cationic monomer" generally refers to a monomer that has a positive charge. Examples include the monomer acryloyloxyethyltrimethylammonium chloride (Q9). The cationic monomer may also be selected from acryloyloxyethyltrimethylammonium chloride (“AETAC”), methacryloyloxyethyltrimethylammonium chloride (“MAETAC”), methacrylamidopropyltrimethylammonium chloride (“MAPTAC”), acrylamidopropyltrimethylammonium chloride (“APTAC”), methacryloyloxyethyldimethylammonium sulfate, diallyldimethylammonium chloride (“DADMAC”); dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates and their quaternary salts or acid salts, including but not limited to dimethylaminoethyl acrylate (“DMAEA”), dimethylaminoethyl methacrylate (“DMAEA”), dimethylaminoethyl acrylate methyl chloride quaternary salt, dimethylaminoethyl acrylate methyl sulfate quaternary salt, dimethylaminoethyl acrylate benzyl chloride quaternary salt, dimethylaminoethyl acrylate sulfate, dimethylaminoethyl acrylate hydrochloride, diethylaminoethyl acrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate dimethylaminoacrylate Dimethylaminoethyl methacrylate methyl sulfate quaternary salt, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, dimethylaminoethyl methacrylate sulfate, dimethylaminoethyl methacrylate hydrochloride, dimethylaminoethyl methacrylate hydrochloride; dialkylaminoalkyl acrylamides and methacrylamides and their quaternary salts or acid salts, including but not limited to acrylamidopropyltrimethylammonium chloride, dimethylaminopropyl acrylamide, dimethylaminopropyl acrylamide methyl sulfate quaternary salt, dimethylaminopropyl acrylamide sulfate, dimethylaminopropyl acrylamide hydrochloride, methacrylamidopropyltrimethylammonium chloride, dimethylaminopropyl methacrylamide, dimethylaminopropyl methacrylamide methyl sulfate quaternary salt, dimethylaminopropyl methacrylamide sulfate, dimethylaminopropyl methacrylamide hydrochloride, diethylaminoethyl acrylate, diethylaminoethyl methacrylate; and diallyl dialkyl ammonium halides, including but not limited to diallyl diethyl ammonium chloride and diallyl dimethyl ammonium chloride (“DADMAC”), and any combination thereof.

[0158] As used herein, the terms “PVAm,” “polyvinylamine,” and “vinylamine polymer” refer to any polymer having vinylamine units (i.e., 1-aminoethylene units or N-vinylamine units). PVAm has a high cationic charge at typical operating pH for papermaking applications. PVAm spontaneously and irreversibly adsorbs onto the surface of cellulose fibers in water, thereby creating cationic surface properties on the fibers. PVAm polymers, typically with high cationic charge density and low molecular weight, are used in papermaking as coagulants to form small fiber flocs without increasing the size of the flocs with increasing PVAm polymer dosage. Therefore, PVAm polymers are widely used to improve vacuum draining rates, press dewatering rates, and reduce dryer steam consumption in recycling paper machines without affecting sheet formation. PVAm is also widely used as a reinforcing agent in papermaking. A significant drawback is that PVAm polymers are very expensive. Many paper mills, especially those producing recycled corrugated board, cannot afford to use PVAm as a filter aid.

[0159] PVAm can be manufactured by free radical polymerization of N-vinylformamide to form poly-N-vinylformamide (PNVF), followed by hydrolysis of the formamide groups to amines, thereby forming PVAm. This hydrolysis can be base-catalyzed, such as by hydroxide ions, or acid-catalyzed. The hydrolysis of PNVF initially forms a copolymer (PNVF-co-PVAm) containing PNVF and PVAm, which can be completely hydrolyzed to form PVAm with almost no residual PNVF.

[0160] In some embodiments, one or more PVAm polymers may comprise a vinylamine polymer and a PNVF-co-PVAm copolymer, containing other cationic, anionic, and / or nonionic monomers, including but not limited to acrylamide, acrylic acid, acrylates, n-butyl acrylate, and polyethyleneimine (i.e., polyaziridinium) monomer units. In some embodiments, the PVAm may have a cationic charge density ranging from 1 mEq to 2 mEq per gram. In some embodiments, the PVAm may have a weight-average molecular weight ranging from 500,000 Da to 2,500,000 Da.

[0161] In some embodiments, the one or more PVAm polymers comprise polymers synthesized by Hoffmann degradation of a base polymer comprising (i) acrylamide; (ii) methacrylamide; (iii) a copolymer of acrylamide and a cationic monomer selected from the group consisting of: dimethylaminoethyl acrylate (DMAEA), quaternized dimethylaminoethyl methacrylate (DMAEMA), dimethyl diallyl ammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC); or (iv) a copolymer of acrylamide and DADMAC.

[0162] In some embodiments, the one or more PVAm polymers comprise polymers synthesized by complete or partial hydrolysis of one or more poly(N-vinylformamide) homopolymers or copolymers, wherein the one or more poly(N-vinylformamide) homopolymers or copolymers are optionally synthesized by free radical polymerization of N-vinylformamide or by free radical polymerization of N-vinylformamide and one or more other monomers, and further comprise a degree of hydrolysis in the range of 1-100 mol%, 20-100 mol%, 40-100 mol%, 60-100 mol%, or 80-100 mol%.

[0163] In some embodiments, the one or more PVAm polymers comprise polymers synthesized by partial hydrolysis of one or more poly(N-vinylformamide) homopolymers, and further comprise a degree of hydrolysis ranging from 30-50 mol%, 35-45 mol%, or about 40 mol%.

[0164] The "degree of hydrolysis" of a PVAm polymer refers to the molar percentage of PNVF units that have been hydrolyzed into vinylamine units. For example, a PNVF-co-PVAm polymer with a degree of hydrolysis of 50 mol% contains N-vinylformamide and vinylamine units in a molar ratio of 1:1. A PVAm with a degree of hydrolysis of 100 mol% contains vinylamine units and no residual N-vinylformamide units. In some embodiments, one or more PVAm polymers may contain a degree of hydrolysis ranging from 30-100 mol%, 40-100 mol%, 60-100 mol%, or 80-100 mol%.

[0165] As used herein, the term "fast reverse cationic emulsion polyacrylamide" or "QIC-EPAM" refers to a high-MW fast reverse cationic retention polymer comprising a cationic acryloyloxyethyltrimethylammonium chloride (Q9) and an acrylamide copolymer having 20 mol% to 30 mol% of Q9 monomer. This copolymer has a standard viscosity (SV) of 2.5 cPs to 3.5 cPs. The optimal MW range, low SV value range, and optimized 3-D structure of QIC-EPAM were achieved through the ingenious use of sodium hypophosphite as a chain transfer agent and methylenebisacrylamide as a crosslinking agent. The reduced molecular weight of QIC-EPAM to a low to medium range is suitable for improving the retention, draining, and fixation of fibers, fine powders, and fillers without compromising sheet forming at elevated polymer dosage levels. The 3-D polymer structure in the fast reverse emulsion was found to enhance colloid and fine powder retention more effectively than conventional linear cationic polymers with high MW (typical SV range = 4.5 cPs to 5.5 cPs). It was discovered that the combination of low SV and high cationic charge can form small and compact fibrous flocs similar to PVAm, and improve the vacuum draining / pressing dewatering effect of 100% recycled paper. The combination of QIC-EPAM and PVAm as an additive for repairing recycled liner paper provides improved retention, gravity draining rate, and DDA draining time without over-flocculation, and allows for a significant reduction in PVAm usage. The QIC-EPAM polymer of this invention is described in U.S. Patent Application No. 63 / 387,298 entitled "Improved Retention Of Engineered Cellulosic Additives Using SynergisticCationic Polymer Combination," which is hereby incorporated by reference.

[0166] As used herein, the term “addition alone” means adding two or more additives (e.g., processing aid components, chemicals, polymers, etc.) to an aqueous suspension of cellulose fibers in any order, either sequentially or simultaneously.

[0167] As used herein, the term "blending" refers to the mixing of two or more chemical additives by any means known in the art prior to the addition of the blended additive to a papermaking process (e.g., to pulp preparation, thick pulp, thin pulp, or paper machine). In some embodiments, retention and filtration aids comprising PVAm and QIC-EPAM are blended in a separate location or on-site. In some embodiments, the blended PVAm and QIC-EPAM are thoroughly mixed by stirring, agitation in a pipeline, or otherwise before being added to the papermaking process.

[0168] Terms and Units

[0169] As used herein, the terms "aqueous solution" or "solution" generally refer to a mixture of water and one or more water-soluble solutes, which are completely dissolved with little or no residual undissolved polymer gel. The solution may be homogeneous. When mixed with excess water, the polymer article preferably dissolves completely, and the resulting polymer solution preferably does not contain discrete polymer particles or residual gel.

[0170] As used herein, the terms "aqueous suspension," "aqueous slurry," or "slurry" generally refer to a heterogeneous mixture of fluids containing sufficiently large insoluble or slightly soluble solid particles to settle. The suspensions and slurries of the present invention may also contain a quantity of solid particles, commonly referred to as colloidal particles, which cannot settle completely or require a long time to settle completely.

[0171] As used herein, the term “consistency” typically refers to the percentage of dried mass in the raw materials, pulp, or mix (i.e., 100% * dried mass / total mass).

[0172] The terms “total solids” or “total suspended solids” are used interchangeably herein and generally refer to the total amount or weight of suspended solids contained in oil sands or other sands containing dispersions. “Total solids” or “total suspended solids” typically excludes dissolved solids.

[0173] As used herein, the term “ppm” refers to parts per million (e.g., mg / L) based on milligrams of solute per liter of aqueous solution or slurry.

[0174] As used herein, the term “lbs / ton” or “# / T” indicates the dry mass pounds of material (e.g., AKD weight per gross dry tonne of suspended solids) added per tonne of suspended solids.

[0175] As used herein, the term “kg / T” or “kg / ton” means the number of kilograms of dry mass (additives, solutes and / or particles) of tonne of slurry, raw materials and / or slurry mix.

[0176] As used herein, the phrase “wt.%” means the dry weight of additives in a formulation, solution, or slurry multiplied by 100% of the dry weight of solids.

[0177] As used herein, the term "CSF" is a measure of the rate at which fibers are drained of water and is commonly used to characterize the degree of fibrillation of fibers in pulp and paper science. Freeness has been shown to be related to fiber surface conditions and swelling (TAPPI 1999b). CSF is obtained by gravity water retention.

[0178] Detailed description of the invention

[0179] The synergistic effect of novel QIC-EPAM with PVAm, recently discovered in pulp containing high levels of recycled contents, has demonstrated unexpected retention and drain performance efficiency without excessive flocculation, and allows for significant reductions in PVAm dosage. In paper mills with high recycled contents (high levels of calcium ions and high conductivity), North American paper manufacturers are seeking effective chemicals that will provide on-machine retention and drain without excessive flocculation.

[0180] Retention rates vary depending on the mechanism (e.g., filtration via mechanical entrainment, electrostatic attraction, and bridging between fibers and fillers in the slurry). Because both cellulose fibers and many common filler materials carry a negative charge, they repel each other. Typically, the only factor that helps improve retention is mechanical entrainment. Therefore, retention aids are commonly used to improve the retention of fibers and fillers on the wire.

[0181] Recycled fiber materials are commonly used as raw materials for paper or paperboard. In addition to fibers, recycled fiber materials also contain high levels of fines and fillers. Greater retention of fines and fillers is highly desirable, allowing for a reduction in cellulose fiber content. Retention in papermaking becomes even more important as inferior pulp is used to reduce papermaking costs. This is due to the higher levels of fines found in lower-quality pulps such as recycled fibers and coated waste paper. Greater retention of fines, fillers, and other pulp components also reduces the amount of these substances lost to white water. This reduces the amount of material waste, waste disposal costs, and the resulting adverse environmental impact.

[0182] Retention and filter aids used in papermaking are typically added to the pulp or feedstock before being added to the headbox of the paper machine. Their purpose is to provide enhanced on-machine retention and dripping, while also offering additional benefits such as improved paper strength and wet pressing properties. These requirements are particularly challenging for papermaking operations in mills with high recycling content. Typical retention and filter aids include high molecular weight cationic polymers or CPAM / silica retention programs. When added to recycled fibers, these additives create large flocculations in the recycled pulp (i.e., over-flocculation), resulting in less uniform recycled paper and poor forming. Poorly formed sheets containing large fiber flocculations will exhibit high gravity dripping rates and will drip rapidly in the initial hydrofoil section of the paper machine. However, this over-flocculated sheet responds poorly to vacuum in later sections of the forming section, leading to reduced vacuum dripping (press dewatering) rates. The sheet will also require increased dryer steam consumption due to the increased water trapped in the large flocculations.

[0183] This invention provides a process for using a novel QIC-EPAM with PVAm as a filter aid / retention aid in the manufacture of recycled OCC liner paper. A surprising synergistic effect between PVAm and the novel QIC-EPAM has been observed in the industrial environment of a paper machine. This synergistic effect allows for a significant reduction in costly PVAm dosage levels while achieving the same or better retention and dripping results without excessive flocculation.

[0184] The retention and filtration aid containing QIC-EPAM + PVAm of this invention offers several advantages over conventional PVAm-only drain / retention processes: 1) QIC-EPAM + PVAm can be used as a pumped product, eliminating the need for conventional emulsion polymer inversion and aging tanks; 2) QIC-EPAM + PVAm provides small, dense fiber flocs like PVAm and improves vacuum draining / pressing dewatering of 100% recycled paper; 3) By combining PVAm with 0.25-1.2 kg / ton QIC-EPAM, a 20-40% reduction in PVAm dosage on the paper machine was observed; 4) The combination of PVAm and QIC-EPAM can be added to the paper machine via the following addition processes: (a) premixing before adding to the thick pulp; (b) premixing before adding to the thin pulp; (c) adding to the thick pulp alone; (d) adding to the thin pulp alone; (e) adding alone, wherein one or more PVAm polymers are added to the thick pulp and one or more QIC-EPAMs are added to the thin pulp; or (f) adding alone, wherein one or more PVAm polymers are added to the thin pulp and one or more QIC-EPAMs are added to the thick pulp.

[0185] This invention generally relates to methods and compositions for manufacturing facial tissues, paper, or paperboard, and for enhancing their retention and drainability. Specifically, this disclosure provides methods for enhancing retention and drainability by adding retention-enhancing and filter-enhancing agents comprising fast reverse cationic emulsion polyacrylamide (QIC-EPAM) and polyethyleneamine (PVAm) polymers. Manufacturing paper under these conditions provides improved retention, gravity drain rate, and DDA drain time without excessive flocculation, and allows for a significant reduction in PVAm usage.

[0186] On one hand, the present invention provides a method for manufacturing facial tissues, paper, or paperboard, the method comprising:

[0187] (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers.

[0188] (b) Optionally dilute the concentrated slurry to form a thinner slurry;

[0189] (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and

[0190] (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard;

[0191] The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising:

[0192] (i) one or more polyethyleneamine (PVAm) polymers; and

[0193] (ii) One or more fast reversed cationic emulsion polyacrylamides (QIC-EPAM), said QIC-EPAM comprising acrylamide (AM) monomer and cationic acryloyloxyethyltrimethylammonium chloride (Q9).

[0194] In some exemplary embodiments of the method, the one or more PVAm polymers and the one or more QIC-EPAMs:

[0195] (a) Premix before adding to the slurry;

[0196] (b) Premix before adding to the slurry;

[0197] (c) Added separately to the concentrated slurry;

[0198] (d) Added separately to the slurry;

[0199] (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or

[0200] (f) Added separately, wherein one or more PVAm polymers are added to the slurry and one or more QIC-EPAMs are added to the concentrate;

[0201] The time following steps (a)-(f) is optionally a mixed time ranging from 0.01 to 10 minutes, 0.1 to 5 minutes, or 1 to 2 minutes.

[0202] In some exemplary embodiments of the method, the one or more PVAm polymers:

[0203] (a) Includes weight-average molecular weights in the range of 50-3000 kDa, 100-2000 kDa, 200-2000 kDa or 400-800 kDa;

[0204] (b) The cation charge density contained as a dry solid at pH 7 in the range of less than 5.0 mEq / g, 0.5–5.0 mEq / g, 1.0–4.0 mEq / g, or 1.5–2.5 mEq / g;

[0205] (c) A polymer synthesized by Hoffmann degradation of a base polymer comprising (i) acrylamide; (ii) methacrylamide; (iii) a copolymer of acrylamide and a cationic monomer selected from the group consisting of: dimethylaminoethyl acrylate (DMAEA), quaternized dimethylaminoethyl methacrylate (DMAEMA), dimethyl diallyl ammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC); or (iv) a copolymer of acrylamide and DADMAC;

[0206] (d) A polymer comprising a polymer synthesized by complete or partial hydrolysis of one or more poly(N-vinylformamide) homopolymers or copolymers, wherein the one or more poly(N-vinylformamide) homopolymers or copolymers are optionally synthesized by free radical polymerization of N-vinylformamide or by free radical polymerization of N-vinylformamide and one or more other monomers, and further comprising a degree of hydrolysis in the range of 1-100 mol%, 20-100 mol%, 40-100 mol%, 60-100 mol%, or 80-100 mol%.

[0207] (e) A polymer synthesized by partial hydrolysis of one or more poly(N-vinylformamide) homopolymers, and further comprising a degree of hydrolysis ranging from 30 to 50 mol%, 35 to 45 mol%, or about 40 mol%;

[0208] (f) Optionally formulated as a dry powder or as an aqueous composition, said aqueous composition comprising, by weight, from about 0.5% to about 30%, optionally more than 2% to about 25%, and more preferably more than about 10% to about 22% PVAm solids; or

[0209] Any combination of (g)(a)-(f).

[0210] In some exemplary embodiments of the method, the one or more rapid reversed cationic emulsion polyacrylamide (QIC-EPAM) are:

[0211] (a) Contains a range of 60-85 wt%, 65-85 wt%, 70-85 wt%, or 70-80 wt% of acrylamide (AM) monomer;

[0212] (b) Contains ≤40wt%, 15-40wt%, 15-35wt%, 15-30wt%, or 20-30wt% cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content; or

[0213] (c) Contains an inverted emulsion, a dry polymer, or an aqueous solution of a polymer, preferably an inverted emulsion;

[0214] (d) Polymer standard viscosity (SV) including ranges of less than or equal to 3.5 cPs, 2.0-3.5, 2.5-3.5 cPs, or 3.0-3.5 cPs; or

[0215] (e) Any combination of the foregoing terms.

[0216] In some exemplary embodiments of the method, the retention aid and filter aid optionally further comprises one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles, wherein:

[0217] (a) The further cationic dry polyacrylamide (DPAM) comprises an acrylamide (AM) monomer and one or more cationic monomers, wherein the one or more cationic monomers are selected from the group consisting of: acryloyloxyethyltrimethylammonium chloride (“AETAC”), methacryloyloxyethyltrimethylammonium chloride (“MAETAC”), methacrylamidepropyltrimethylammonium chloride (“MAPTAC”), acrylamidepropyltrimethylammonium chloride (“APTAC”), methacryloyloxyethyldimethylammonium sulfate, diallyldimethylammonium chloride (“DADMAC”); dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates and their quaternary ammonium salts or acid salts, including but not limited to: dimethylaminoethyl acrylate (“DMAEA”), dimethylaminoethyl methacrylate (“DMAEA”), dimethylaminoethyl acrylate methyl chloride quaternary ammonium salt, dimethylaminoethyl acrylate methyl sulfate quaternary ammonium salt, dimethylaminoethyl acrylate benzyl chloride quaternary ammonium salt, dimethylaminoethyl acrylate sulfate, dimethylaminoethyl acrylate hydrochloride, diethylaminoethyl acrylate methyl chloride quaternary ammonium salt, Dimethylaminoethyl methacrylate methyl chloride quaternary ammonium salt, dimethylaminoethyl methacrylate methyl sulfate quaternary ammonium salt, dimethylaminoethyl methacrylate benzyl chloride quaternary ammonium salt, dimethylaminoethyl methacrylate sulfate, dimethylaminoethyl methacrylate hydrochloride, methacryloyldimethylaminoethyl methacrylate hydrochloride; dialkylaminoalkylacrylamides and methacrylamides and their quaternary ammonium salts or acid salts, including but not limited to acrylamide propyltrimethylammonium chloride, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylacrylamide methyltrimethylammonium chloride ... Diallyl dimethylaminopropylacrylamide sulfate, dimethylaminopropylacrylamide hydrochloride, methacrylamide propyltrimethylammonium chloride, dimethylaminopropylmethacrylamide, dimethylaminopropylmethacrylamide methyl sulfate quaternary ammonium salt, dimethylaminopropylmethacrylamide sulfate, dimethylaminopropylmethacrylamide hydrochloride, diethylaminoethyl acrylate, diethylaminoethyl methacrylate; and diallyl dialkylammonium halides, including but not limited to diallyl diethylammonium chloride and diallyl dimethylammonium chloride (“DADMAC”), and any combination thereof; and

[0218] (b) The one or more inorganic microparticles are selected from the group consisting of microparticles and nanoparticles including: silica microparticles; colloidal silica; layered aluminum silicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite.

[0219] In some exemplary embodiments, the method includes one or more of the following:

[0220] (a) The one or more fast reverse cationic emulsion polyacrylamide (QIC-EPAM) comprises an acrylamide (AM) monomer content ranging from 70-80 wt% and a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; comprises a reverse emulsion; and comprises a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs.

[0221] (b) The one or more PVAm polymers have a weight-average molecular weight in the range of 400-800 kDa; or

[0222] (c) The one or more inorganic particles comprise bentonite, sodium bentonite or calcium bentonite.

[0223] In some exemplary embodiments of the method, when added to the thick slurry and / or the thin slurry:

[0224] (a) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1;

[0225] (b) The one or more PVAm polymers are added at a dosage ranging from 0.2-12 kg / t, 0.2-10 kg / t, 0.2-8 kg / t, 0.2-6 kg / t, 0.2-2 kg / t or 0.2-0.6 kg / t;

[0226] (c) The one or more QIC-EPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.1-0.2 kg / t;

[0227] (d) The one or more DPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.2-0.4 kg / t;

[0228] (e) The one or more inorganic microparticles are added at a dosage ranging from 0.1-4 kg / t, 1-4 kg / t, or 2-4 kg / t; or

[0229] Any combination of (f)(a)-(e).

[0230] In some exemplary embodiments, the method includes one or more of the following:

[0231] (a) The slurry has a consistency ranging from 1-5%, 1-3%, or 1-1.5%, where consistency refers to the weight percentage of total suspended solids in the aqueous slurry.

[0232] (b) The slurry has a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%;

[0233] (c) Diluting the concentrated slurry by adding water, chemical water, synthetic water, white water, and / or process water to form the thin slurry; or

[0234] (d) The concentrated pulp and / or the thin pulp optionally further comprise one or more papermaking-related additives, including but not limited to starch, dyes, bleaching agents, sizing agents, wet strength agents, dry strength agents, or anti-sticking agents; or

[0235] Any combination of (e), (a), and (c).

[0236] In some exemplary embodiments of the method, the aqueous suspension of cellulose fibers contains a pH in the range of 4-8, 4-7.5, 4-7, 4.5-7, or 5-7, and further comprises:

[0237] (a) A certain percentage of recycled cellulose fibers, ranging from 40-100% by weight, 50-100% by weight, 60-100% by weight, 80-100% by weight, or 90-100% by weight of recycled cellulose fibers.

[0238] (b) A combination of one or more recycled fibers, said one or more recycled fibers optionally obtained from sources including, but not limited to, used corrugated cardboard (OCC), mixed office waste (MOW), mixed office paper, old newspaper pulp (ONP), old magazines (OMG), factory waste paper fibers, or coated waste paper.

[0239] (c) Optional softwood fiber, hardwood fiber, refined fiber, non-wood fiber including but not limited to wheat straw pulp, and mixtures of any of the foregoing;

[0240] (d) Optionally, the pulp is selected from the following: kraft pulp, unbleached kraft pulp, bleached pulp, unbleached pulp, process water from pulp, paper and / or paperboard production, neutral sulfite semi-chemical (NSSC) pulp, mechanical pulp, non-wood pulp, and mixtures of any of the foregoing; or

[0241] (e) A certain amount of fine pulp powder and / or a certain amount of mineral filler, ranging from 5-30% by mass of the total solids in the aqueous suspension, wherein the certain amount of fine pulp powder comprises pulp particles small enough to pass through pores with a diameter of 76 µm, and the certain amount of mineral filler comprises calcium carbonate, clay, kaolinite, aluminum silicate, talc, and / or gypsum; or

[0242] (f) and the combination of (a)-(e).

[0243] In some exemplary embodiments of the method, when used to manufacture facial tissues, paper, or paperboard, the method causes the following when compared to the same method performed without (i) the addition of one or more PVAm or (ii) the addition of one or more QIC-EPAM:

[0244] (a) Increased retention of cellulose fibers;

[0245] (b) Increased retention of pulp fines and / or mineral fillers;

[0246] (c) The draining rate is faster on the wire mesh screen;

[0247] (d) The rate of pressing and dehydration increases;

[0248] (e) Reduced steam consumption in the dryer;

[0249] (f) Improvements in the quality of facial tissues, paper, or paperboard, such as those determined by a reduction in permeability;

[0250] (g) Reduced PVAm dose;

[0251] (h) The combination of QIC-EPAM and PVAm synergistically improves the paper machine's draining rate;

[0252] (i) The combination of QIC-EPAM and PVAm synergistically increases Canadian standard free radical (CSF); or

[0253] Any combination of (j)(a)-(i).

[0254] On the other hand, the present invention provides a method for manufacturing facial tissues, paper, boxboard, or paperboard, the method comprising:

[0255] (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers.

[0256] (b) Optionally dilute the concentrated slurry to form a thinner slurry;

[0257] (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and

[0258] (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard;

[0259] The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising:

[0260] (i) One or more polyvinylamine (PVAm) polymers;

[0261] (ii) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0262] (iii) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite.

[0263] In some exemplary embodiments of the method, the one or more PVAm polymers and the one or more QIC-EPAMs:

[0264] (a) Premix before adding to the slurry;

[0265] (b) Premix before adding to the slurry;

[0266] (c) Added separately to the concentrated slurry;

[0267] (d) Added separately to the slurry;

[0268] (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or

[0269] (f) Added separately, wherein one or more PVAm polymers are added to the slurry and one or more QIC-EPAMs are added to the concentrate.

[0270] On the other hand, the present invention provides a slurry comprising an aqueous suspension having a consistency ranging from 1-5%, 1-3%, or 1-1.5%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising:

[0271] (a) One or more polyethyleneamine (PVAm) polymers;

[0272] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0273] (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite;

[0274] in

[0275] (i) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1;

[0276] (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry;

[0277] (iii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

[0278] On the other hand, the present invention provides a slurry comprising an aqueous suspension having a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising:

[0279] (a) One or more polyethyleneamine (PVAm) polymers;

[0280] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0281] (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite;

[0282] in

[0283] (i) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry;

[0284] (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

[0285] On the other hand, the present invention provides a composition for use as a retention aid and filter aid in the manufacture of facial tissues, paper, or paperboard, the composition comprising:

[0286] (a) One or more polyethyleneamine (PVAm) polymers;

[0287] (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and

[0288] (c) Optionally one or more anionic organic or inorganic microparticles, said one or more anionic organic or inorganic microparticles being selected from the group consisting of microparticles and nanoparticles of the following: silica microparticles; colloidal silica; layered aluminosilicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite; and anionic polymer microparticles, including but not limited to highly structured anionic polyacrylamide.

[0289] The methods and compositions illustratively disclosed herein may be practiced in the absence of any elements not specifically disclosed herein and / or any elements specifically disclosed herein. Exemplary embodiments of the invention and their advantages will be further disclosed in the following examples.

[0290] Example

[0291] The embodiments provided herein are for illustrative purposes only, in order to provide a more complete understanding of the invention. These embodiments should not be construed as limiting the invention in any way.

[0292] Example 1: Experimental Procedure and Chemical Additives

[0293] Determination of DDA draining time

[0294] Cellulose fiber webs were manufactured, and the draining time was analyzed using a Dynamic Drain Analyzer (DDA) according to the following: Aliquots (500-700 mL) of cellulose feedstock with a consistency of 0.5 wt% to 0.7 wt% (Total Suspended Solids, TSS) were mixed with chemical additives. The chemicals were added in chronological order simulating the addition positions on the paper machine. Blank samples contained no added chemicals. After mixing, the flocculated feedstock was drained through a 60-mesh sieve under vacuum (250 mBar). The draining time was determined by measuring the time until the vacuum broke (i.e., a rapid increase in vacuum pressure). A shorter draining time indicated better draining. The DDA draining gain % was determined by calculating the % reduction in draining time compared to the blank (without chemical additives). For this embodiment, a higher value is preferred. Figure 1-2 The higher DDA drain gain percentage shown is for the lower drain limit. The DDA filtrate is used for the turbidity test as described below.

[0295] Determination of DDA penetration rate

[0296] The permeability of the fiber pad in the DDA drip test was determined by tracking the airflow time within the fiber pad during the DDA drip test. The permeability gain (%) was determined by calculating the increase in permeability compared to the blank (no chemical additives). The percentage permeability gain of the sheet obtained using the polymer is preferably lower than [value missing]. Figure 1-2 The permeability upper limit is shown. Permeability gain percentage exceeding the permeability upper limit indicates excessive flocculation of cellulose fibers, which leads to larger flocs and poor sheet formation.

[0297] Determination of filtrate turbidity

[0298] Turbidity testing was performed on the filtrate from the DDA screening as an indicator of retention. The turbidity of the treated filtrate was measured using a Hach 2100Q turbidimeter. The 2100Q portable turbidimeter operates based on the principle of turbidity measurement. The optical system includes a tungsten filament lamp, a 90° detector for monitoring scattered light, and a transmitted light detector. The instrument's microprocessor calculates the ratio of signals from the 90° detector and the transmitted light detector, which corrects for interference from color and / or light-absorbing materials. The instrument range is 0 NTU to 1000 NTU. Lower turbidity levels typically increase with higher retention rates of fillers, fine powders, and / or contaminants in the slurry within the fiber pad.

[0299] Gravity water retention

[0300] The draining rate of diluted pulp suspensions was determined using a Canadian Standard Freeness Tester and reported in Canadian Standard Freeness (CSF). The CSF test measures the free water draining rate of a diluted pulp suspension with a consistency of 3 g pulp per 1 L of water. CSF is a measure of the water draining rate of fibers and is commonly used to characterize the degree of fibrillation in pulp and paper science. The freeness of the raw material is generally related to fiber surface condition and swelling (TAPPI 1999b). In this study, a higher gravity draining rate (i.e., a higher CSF) was preferred, and it was shown that the added retained polymer had a positive effect on fiber surface conditions and fiber swelling.

[0301] Chemical additives

[0302] The chemical additives shown in Table 1 were evaluated as retention and filtration aids in Examples 2-4, and include polyethyleneamine (PVAm1-3) and fast reverse cationic emulsion polyacrylamide (QIC-EPAM) comprising cationic [2-(acryloyloxy)ethyl]trimethylammonium chloride monomer (Q9) and acrylamide monomer. Conventional additives (e.g., DPAM and bentonite) were also added to the fiber raw material if indicated.

[0303] Table 1: Chemical additives tested as retention and filtration aids in Examples 2-4.

[0304]

[0305] Example 2: Evaluation of QIC-EPAM with PVAm as a retention and filtration aid for improving DDA draining and permeability in recycled OCC slurry.

[0306] Polyvinylamine (PVAm 1-3) and rapid reverse-phase cationic EPAM (QIC-EPAM) (see Table 1) were evaluated individually and in combination as retention and filtration aids for recycled corrugated board made from 100% recycled old corrugated board (OCC) and waste paper fiber raw materials from North American paper mills.

[0307] The OCC fiber raw material was diluted to form a slurry with a consistency of 0.5-0.7 wt% (total suspended solids, TSS). Sheets were manufactured, and the DDA draining time and DDA permeability were determined according to Example 1.

[0308] PVAm1 was evaluated individually at doses ranging from 2 to 10 kg / t. PVAm2 was evaluated individually at doses ranging from 2 to 12 kg / t. PVAm3 was evaluated individually at doses ranging from 0.2 to 1 kg / t. In these experiments, PVAm was added directly to the slurry.

[0309] The potential synergistic improvement in drainability and permeability of the combination of QIC-EPAM and PVAm1-3 was also evaluated. QIC-EPAM (dosage = 0.1-0.2 kg / t) was blended with one of PVAm1 (dosage = 6 kg / t), PVAm2 (dosage = 6 kg / t), or PVAm3 (dosage = 0.6 kg / t) and then added to the slurry.

[0310] The results are shown in Figure 1 In this embodiment, it is preferred to be higher than... Figure 1 The higher DDA drip gain percentage shown in the drip lower limit line is preferred. Figure 1 The percentage of permeability gain for the sheet is shown above the upper limit of permeability. A percentage of permeability gain exceeding the upper limit (i.e., over-permeability) indicates excessive flocculation of the cellulose fibers, which leads to larger flocs and poor sheet formation. Permeability is a property of porous materials that indicates the ability of a fluid (gas or liquid) to flow through them. Fluids flow more easily through materials with high permeability than materials with low permeability. The permeability of a medium is related to its porosity, as well as the shape of the pores in the medium and their connectivity. The increase in the permeability of the fiber mat is caused by the chemical flocculation of the fibers.

[0311] These results demonstrate that, compared to PVAm alone, the retention and filtration aids of the present invention (e.g., PVAm combined with QIC-EPAM) significantly improve draining (i.e., shorter draining time, where the draining gain is above the lower limit) without over-permeation (i.e., permeability gain equal to or below the upper limit) of sheets manufactured from 100% recycled pulp. With increasing QIC-EPAM dosage, the retention and filtration aids of the present invention improve draining in a dose-dependent manner.

[0312] Surprisingly, the retention and filtration aids of this invention (e.g., PVAm with QIC-EPAM) allow for a significant reduction in PVAm dosage while providing improved DDA draining without excessive penetration of the liner sheet. A 20-40% reduction in PVAm dosage was observed on customer paper machines using 0.1-0.2 kg / t of QIC-EPAM. Optimal results were achieved using QIC-EPAM + PVAm1, reducing PVAm1 from 8-10 kg / t to 6 kg / t. The greatest enhancement was observed using QIC-EPAM + PVAm3 at 0.6 kg / t.

[0313] Without being bound by theory, it is reasonable to assume that the combination of QIC-EPAM and PVAm avoids excessive flocculation of fibrous raw materials by allowing the formation of smaller fibrous flocs (likely through binding with PVAm), and then effectively retains smaller flocs without over-flocculation through association with the high cationic charge 3-D structure of QIC-EPAM. Using sodium hypophosphite as a chain transfer agent and methylenebisacrylamide as a crosslinking agent to control the 3-D structure of QIC-EPAM, it was found to effectively enhance the retention of colloids and fine powders compared to linear cationic polymers.

[0314] Furthermore, and without being bound by theory, it is reasonable to consider that combining a higher molecular weight QIC-EPAM (MW = 2-3 million Da) with a lower MW PVAm (MW = less than 2 million Da, preferably 500,000 Da) is advantageous. QIC-EPAM is a cationic quaternary ammonium copolyacrylamide with a standard viscosity (SV) of 2.5-3.5 cPs and a 20-30 mol% Q9 cationic monomer content. The molecular weight of QIC-EPAM is suitable for improving retention, draining, and fixation without impairing sheet forming at elevated polymer dosage levels. The combination of high cationic charge, higher MW QIC-EPAM with lower MW PVAm may form small and dense fibrous flocs to compensate for the lack of high MW in PVAM, thereby making PVAm more effective and improving vacuum draining and press dewatering of 100% recycled paper.

[0315] These results provide proof of concept that the retention and filtration aids of the present invention (e.g., QIC-EPAM + PVAm) provide enhanced draining without excessive flocculation compared to PVAm alone. Adding QIC-EPAM + PVAm to recycled fiber feedstock results in faster draining, reduced dryer steam usage, improved liner quality (i.e., uniformity and permeability), and a significant reduction in total PVAm dosage in industrial environments.

[0316] Example 3: Evaluation of QIC-EPAM with PVAm as a retention and filtration aid for improving DDA draining and retention rates in recycled OCC slurry (blended versus added alone).

[0317] PVAm 1-3 and QIC-EPAM (see Table 1) were evaluated as retention and filtration aids for recycled corrugated board manufactured from 100% recycled old corrugated board (OCC) fiber raw materials from North American paper mills.

[0318] The OCC fiber raw material was diluted to form a slurry with a consistency of 0.5-0.7 wt% (total suspended solids, TSS). Recycled liner paper was manufactured, and the DDA draining time was evaluated, as well as the turbidity of the resulting DDA filtrate, according to Example 1.

[0319] PVAm 1-3 were evaluated separately, with PVAm 1-2 at 6 kg / t and PVAm 3 at 0.6 kg / t. In these experiments, PVAm was added directly to the slurry.

[0320] The potential synergistic improvement in drainability and permeability of combinations of QIC-EPAM (dosage = 0.1–0.2 kg / t) and PVAm1–3 (dosage = 6 kg / t for PVAm1–2 and 0.6 kg / t for PVAm3) were also evaluated (blending versus adding alone). For blending experiments, QIC-EPAM was blended with PVAm1, PVAm2, or PVAm3 before being added to the slurry. For adding alone experiments, QIC-EPAM and PVAm1–3 were added to the slurry individually.

[0321] The results are shown in Figure 2 In this embodiment, lower turbidity is preferred and indicates higher fiber retention.

[0322] These results demonstrate that the retention and filtration aids of this invention (e.g., PVAm + QIC-EPAM) significantly improve draining time and fiber retention, both when blended before addition and when added alone. Notably, the draining gain in all blending experiments was above the lower limit. Optimal results were achieved by combining QIC-EPAM and PVAm1. This combination achieved the highest DDA draining gain and the lowest turbidity for both blending and individual addition experiments.

[0323] These results provide preliminary proof of the concept that the retention and filtration aids of the present invention (e.g., QIC-EPAM + PVAm) can be added to the feedstock in blends or alone to improve the draining and retention rates (i.e., shorter draining times and lower turbidity) of liner paper made from 100% recycled pulp. Adding QIC-EPAM + PVAm to the recycled fiber feedstock results in faster draining, reduced dryer steam usage, and significantly improved fiber retention in industrial environments.

[0324] Example 4: Evaluation of QIC-EPAM with PVAm as a retention and filtration aid in recycled pulping and conventional paper additives

[0325] For the present embodiment, PVAm3 and QIC-EPAM (see Table 1) as retention and filtration aids for recycled corrugated board (DPAM and bentonite) were evaluated, the recycled corrugated board being manufactured from 100% recycled old corrugated board (OCC) fiber raw materials from North American paper mills.

[0326] The OCC fiber raw material was diluted to form a slurry with a consistency of 0.5-0.7 wt% (total suspended solids, TSS). Recycled liner paper was manufactured, and the DDA draining time and gravity water retention (CSF) were evaluated according to Example 1.

[0327] PVAm3 was evaluated with increased dosages (e.g., 0.5 kg / t, 0.8 kg / t, and 1 kg / t) as well as DPAM and bentonite. QIC-EPAM (0.25 kg / t and 0.5 kg / t) was evaluated alone and in combination with PVAm3 (0.5 kg / t and 0.8 kg / t).

[0328] Figure 3 and Figure 4 The water retention capacity (CSF) and DDA draining time are shown separately.

[0329] Figure 3 The results showed that the addition of QIC-EPAM significantly improved the gravity draining rate of PVAm3. CSF is a measure of the water draining rate of fibers and is commonly used to characterize the degree of fibrillation in pulp and paper science. The degree of freeness of the raw material is generally related to the surface condition and swelling of the fibers (TAPPI 1999b). In this study, a higher gravity draining rate (i.e., a higher CSF) was preferred, and the added retained polymer was shown to have a positive effect on fiber surface conditions and fiber swelling.

[0330] from Figure 3 Surprisingly, it was found that the retention aids and filter aids of the present invention (e.g., PVAm and QIC-EPAM) allow for a significant 50% reduction in the PVAm3 dosage, from 1 kg / t to 0.5 kg / t, while achieving better results with the same total retention aid dosage (i.e., a total of 1 kg / t). Figure 4 As can be seen, there is a similar enhancement in DDA draining time, where the addition of QIC-EPAM reduces PVAm3 by 20-50%, while achieving similar or better DDA draining results. The basic principle of the performance enhancement of QIC-EPAM + PVAm3 can be seen in Example 2.

[0331] These results further provide proof of concept that adding the retention and filtration aids of the present invention (e.g., QIC-EPAM + PVAm3) to recycled fiber feedstock containing conventional additives (e.g., bentonite and DPAM) results in faster draining and a significant reduction in total PVAm dosage in industrial environments, and demonstrates that the QIC-EPAM + PVAm3 of the present invention will be effective in the presence of other papermaking additives.

Claims

1. A method for manufacturing facial tissues, paper, or paperboard, the method comprising: (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers. (b) Optionally dilute the concentrated slurry to form a thinner slurry; (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard; The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising: (i) one or more polyethyleneamine (PVAm) polymers; and (ii) One or more fast reversed cationic emulsion polyacrylamides (QIC-EPAM), said QIC-EPAM comprising acrylamide (AM) monomer and cationic acryloyloxyethyltrimethylammonium chloride (Q9).

2. The method according to claim 1, wherein the one or more PVAm polymers and the one or more QIC-EPAMs are: (a) Premix before adding to the slurry; (b) Premix before adding to the slurry; (c) Added separately to the concentrated slurry; (d) Added separately to the slurry; (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or (f) Added separately, wherein the one or more PVAm polymers are added to the slurry and the one or more QIC-EPAMs are added to the concentrate; The time following steps (a)-(f) is optionally a mixed time ranging from 0.01 to 10 minutes, 0.1 to 5 minutes, or 1 to 2 minutes.

3. The method according to any one of the preceding claims, wherein the one or more PVAm polymers: (a) Includes weight-average molecular weights in the range of 50-3000 kDa, 100-2000 kDa, 200-2000 kDa or 400-800 kDa; (b) The cation charge density contained as a dry solid at pH 7 in the range of less than 5.0 mEq / g, 0.5–5.0 mEq / g, 1.0–4.0 mEq / g, or 1.5–2.5 mEq / g; (c) A polymer synthesized by Hofmann degradation of a base polymer comprising (i) acrylamide; (ii) methacrylamide; (iii) a copolymer of acrylamide and a cationic monomer selected from the group consisting of: dimethylaminoethyl acrylate (DMAEA), quaternized dimethylaminoethyl methacrylate (DMAEMA), dimethyl diallyl ammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC); or (iv) a copolymer of acrylamide and DADMAC; (d) A polymer comprising a polymer synthesized by complete or partial hydrolysis of one or more poly(N-vinylformamide) homopolymers or copolymers, wherein the one or more poly(N-vinylformamide) homopolymers or copolymers are optionally synthesized by free radical polymerization of N-vinylformamide or by free radical polymerization of N-vinylformamide and one or more other monomers, and further comprising a degree of hydrolysis in the range of 1-100 mol%, 20-100 mol%, 40-100 mol%, 60-100 mol%, or 80-100 mol%. (e) A polymer synthesized by partial hydrolysis of one or more poly(N-vinylformamide) homopolymers, and further comprising a degree of hydrolysis ranging from 30 to 50 mol%, 35 to 45 mol%, or about 40 mol%; (f) Optionally formulated as a dry powder or as an aqueous composition, said aqueous composition comprising, by weight, from about 0.5% to about 30%, optionally more than 2% to about 25%, and more preferably more than about 10% to about 22% PVAm solids; or Any combination of (g)(a)-(f).

4. The method according to any one of the preceding claims, wherein the one or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM) are: (a) Contains a range of 60-85 wt%, 65-85 wt%, 70-85 wt%, or 70-80 wt% of acrylamide (AM) monomer; (b) The content of cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer in the range of ≤40wt%, 15-40wt%, 15-35wt%, 15-30wt%, or 20-30wt%; (c) Contains an inverted emulsion, a dry polymer, or an aqueous solution of a polymer, preferably an inverted emulsion; (d) Polymer standard viscosity (SV) including ranges of less than or equal to 3.5 cPs, 2.0-3.5, 2.5-3.5 cPs, or 3.0-3.5 cPs; or (e) Any combination of the foregoing terms.

5. The method of claim 1, wherein the retention aid and filter aid optionally further comprises one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles, wherein: (a) The plurality of cationic dry polyacrylamides (DPAM) comprise an acrylamide (AM) monomer and one or more cationic monomers, wherein the one or more cationic monomers are selected from the group consisting of: acryloyloxyethyltrimethylammonium chloride ("AETAC"), methacryloyloxyethyltrimethylammonium chloride ("MAETAC"), methacrylamidopropyltrimethylammonium chloride ("MAPTAC"), acrylamidopropyltrimethylammonium chloride ("APTAC"), methacryloyloxyethyldimethylammonium sulfate, diallyldimethylammonium chloride ("DADMAC"); dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates and their quaternary salts or acid salts, including but not limited to dimethylaminoethyl acrylate ("DMAEA"), dimethylaminoethyl methacrylate ("DMAEA"), dimethylaminoethyl acrylate methyl chloride quaternary salt, dimethylaminoethyl acrylate methyl sulfate quaternary salt, dimethylaminoethyl acrylate benzyl chloride quaternary salt, dimethylaminoethyl acrylate sulfate, dimethylaminoethyl acrylate hydrochloride, diethylaminoethyl acrylate methyl chloride Quaternary salts of methacrylates, including dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate methyl sulfate quaternary salt, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, dimethylaminoethyl methacrylate sulfate, dimethylaminoethyl methacrylate hydrochloride, and dimethylaminoethyl methacrylate hydrochloride; dialkylaminoalkylacrylamides and methacrylamides and their quaternary salts or acid salts, including but not limited to acrylamidopropyltrimethylammonium chloride, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl sulfate quaternary salt, and dimethylaminopropyl... Acrylamide sulfate, dimethylaminopropylacrylamide hydrochloride, methacrylamide propyltrimethylammonium chloride, dimethylaminopropylmethacrylamide, dimethylaminopropylmethacrylamide methyl sulfate quaternary salt, dimethylaminopropylmethacrylamide sulfate, dimethylaminopropylmethacrylamide hydrochloride, diethylaminoethyl acrylate, diethylaminoethyl methacrylate; and diallyl dialkyl ammonium halides, including but not limited to diallyl diethylammonium chloride and diallyl dimethylammonium chloride ("DADMAC"), and any combination thereof; and (b) The one or more inorganic microparticles are selected from the group consisting of microparticles and nanoparticles including: silica microparticles; colloidal silica; layered aluminum silicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite.

6. The method according to any one of the preceding claims, wherein: (a) The one or more fast reverse cationic emulsion polyacrylamide (QIC-EPAM) comprises an acrylamide (AM) monomer content ranging from 70-80 wt% and a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; comprises a reverse emulsion; and comprises a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs. (b) The one or more PVAm polymers have a weight-average molecular weight in the range of 400-800 kDa; or (c) The one or more inorganic particles comprise bentonite, sodium bentonite or calcium bentonite.

7. The method according to any one of the preceding claims, wherein when added to the thick slurry and / or the thin slurry: (a) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1; (b) The one or more PVAm polymers are added at a dosage ranging from 0.2-12 kg / t, 0.2-10 kg / t, 0.2-8 kg / t, 0.2-6 kg / t, 0.2-2 kg / t or 0.2-0.6 kg / t; (c) The one or more QIC-EPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.1-0.2 kg / t; (d) The one or more DPAMs are added at a dosage ranging from 0.1-1 kg / t, 0.1-0.5 kg / t, or 0.2-0.4 kg / t; (e) The one or more inorganic microparticles are added at a dosage ranging from 0.1-4 kg / t, 1-4 kg / t, or 2-4 kg / t; or Any combination of (f)(a)-(e).

8. The method according to any one of the preceding claims, wherein: (a) The slurry has a consistency ranging from 1-5%, 1-3%, or 1-1.5%, where consistency refers to the weight percentage of total suspended solids in the aqueous slurry. (b) The slurry has a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%; (c) The concentrated slurry is diluted by adding water, chemical water, synthetic water, white water and / or process water to form the thin slurry; (d) The concentrated pulp and / or the thin pulp optionally further comprise one or more papermaking-related additives, including but not limited to starch, dyes, bleaching agents, sizing agents, wet strength agents, dry strength agents, or anti-sticking agents; or Any combination of (e) (a) to (c).

9. The method according to any one of the preceding claims, wherein the aqueous suspension of cellulose fibers comprises a pH in the range of 4-8, 4-7.5, 4-7, 4.5-7, or 5-7, and further comprises: (a) A certain percentage of recycled cellulose fibers, ranging from 40-100% by weight, 50-100% by weight, 60-100% by weight, 80-100% by weight, or 90-100% by weight of recycled cellulose fibers. (b) A combination of one or more recycled fibers, said one or more recycled fibers optionally obtained from sources including, but not limited to, used corrugated cardboard (OCC), mixed office waste (MOW), mixed office paper, old newspaper pulp (ONP), old magazines (OMG), factory waste paper fibers, or coated waste paper. (c) Optional softwood fiber, hardwood fiber, refined fiber, non-wood fiber including but not limited to wheat straw pulp, and mixtures of any of the foregoing; (d) Optionally, the pulp is selected from the following: kraft pulp, unbleached kraft pulp, bleached pulp, unbleached pulp, process water from pulp, paper and / or paperboard production, neutral sulfite semi-chemical (NSSC) pulp, mechanical pulp, non-wood pulp, and mixtures of any of the foregoing. (e) A certain amount of fine pulp powder and / or a certain amount of mineral filler, ranging from 5-30% by mass of the total solids in the aqueous suspension, wherein the certain amount of fine pulp powder comprises pulp particles small enough to pass through pores with a diameter of 76 µm, and the certain amount of mineral filler comprises calcium carbonate, clay, kaolinite, aluminum silicate, talc, and / or gypsum; or (f) and the combination of (a)-(e).

10. The method according to any one of the preceding claims, wherein when used for manufacturing facial tissues, paper, or paperboard, the method causes, compared to the same method performed without (i) the addition of said one or more PVAm or (ii) the addition of said one or more QIC-EPAM, the method results in: (a) Increased retention of cellulose fibers; (b) Increased retention of pulp fines and / or mineral fillers; (c) The draining rate is faster on the wire mesh screen; (d) The rate of pressing and dehydration increases; (e) Reduced steam consumption in the dryer; (f) Improvements in the quality of facial tissues, paper, or paperboard, such as those determined by a reduction in permeability; (g) Reduced PVAm dose; (h) The combination of QIC-EPAM and PVAm synergistically improves the paper machine's draining rate; (i) The combination of QIC-EPAM and PVAm synergistically increases Canadian standard free radical (CSF); or Any combination of (j)(a) to (i).

11. A method for manufacturing facial tissues, paper, boxboard, or paperboard, the method comprising: (a) Forming or providing a slurry comprising an aqueous suspension of cellulose fibers, optionally comprising 40-100% by weight, 60-100% by weight, or 80-100% by weight of recycled cellulose fibers. (b) Optionally dilute the concentrated slurry to form a thinner slurry; (c) The thick pulp and / or the thin pulp are introduced into the headbox of a paper machine and then drained on a wire screen, thereby removing sufficient water to form a wet fiber web; and (d) Pressing and drying the wet fiber web to obtain facial tissues, paper, or paperboard; The method comprises treating the concentrated slurry and / or the diluted slurry with a retention and filtration aid prior to step (c), the retention and filtration aid comprising: (i) One or more polyvinylamine (PVAm) polymers; (ii) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and (iii) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite.

12. The method of claim 12, wherein the one or more PVAm polymers and the one or more QIC-EPAMs are: (a) Premix before adding to the slurry; (b) Premix before adding to the slurry; (c) Added separately to the concentrated slurry; (d) Added separately to the slurry; (e) Added separately, wherein one or more PVAm polymers are added to the concentrated slurry and one or more QIC-EPAMs are added to the diluted slurry; or (f) Added separately, wherein one or more PVAm polymers are added to the slurry and one or more QIC-EPAMs are added to the concentrate.

13. A slurry comprising an aqueous suspension having a consistency ranging from 1-5%, 1-3%, or 1-1.5%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising: (a) One or more polyethyleneamine (PVAm) polymers; (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite; in (i) The ratio of the one or more QIC-EPAMs to the one or more PVAms contained in the retention aid and filter aid is in the range of 1:60 to 1:1; 1:30 to 1:1; 1:6 to 1:1; or 1:3 to 1:1; (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry; (iii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

14. A slurry comprising an aqueous suspension having a consistency ranging from 0.3-1%, 0.4-1%, 0.5-1%, or 0.5-0.7%; a recycled cellulose fiber content ranging from 40-100%; and a retention and filtration aid comprising: (a) One or more polyethyleneamine (PVAm) polymers; (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and (c) Optionally, one or more cationic dry polyacrylamide (DPAM) and / or one or more inorganic microparticles containing bentonite; in (i) The one or more PVAm polymers and the one or more QIC-EPAMs are premixed before being added to the slurry; (ii) The one or more PVAm polymers and the one or more QIC-EPAMs are added separately to the slurry.

15. A composition for use as a retention aid or filter aid in the manufacture of facial tissues, paper, or paperboard, said composition comprising: (a) One or more polyethyleneamine (PVAm) polymers; (b) One or more rapid reverse cationic emulsion polyacrylamides (QIC-EPAM), wherein the one or more QIC-EPAMs contain an acrylamide (AM) monomer content ranging from 70-80 wt%; a cationic acryloyloxyethyltrimethylammonium chloride (Q9) monomer content ranging from 20-30 wt%; wherein the QIC-EPAMs contain a reverse emulsion; and a polymer standard viscosity (SV) ranging from 3.0-3.5 cPs; and (c) Optionally one or more anionic organic or inorganic microparticles, said one or more anionic organic or inorganic microparticles being selected from the group consisting of microparticles and nanoparticles of the following: silica microparticles; colloidal silica; layered aluminosilicate mineral particles, including but not limited to bentonite, sodium bentonite, calcium bentonite and montmorillonite; and anionic polymer microparticles, including but not limited to highly structured anionic polyacrylamide.

Images