CA3050358C - High molecular weight temporary wet strength resin for paper - Google Patents

Abstract

A cellulose reactive glyoxalated copolymer composition for use in manufacturing paper products comprises an aqueous medium and 0.1 to 4 weight % of a cellulose reactive glyoxalated vinylamide copolymer. The glyoxalated vinylamide copolymer is obtained by reaction in an aqueous reaction medium of glyoxal and a cationic vinylamide copolymer, a dry weight of glyoxal: cationic copolymer in the aqueous reaction medium ranging from 5 to 40 glyoxal to 95 to 60 cationic vinylamide copolymer. The aqueous reaction medium has a total solids concentration of from 0.5 to 2.5%. The cationic vinylamide copolymer has a weight average molecular weight of 20,500 Daltons to 46,100 Daltons and comprises 5 to 95 weight % diallyldimethyl ammonium halide monomer and 95 to 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation.

Description

HIGH MOLECULAR WECGHT TEMPORARY WET STRENGTH RESIN FOR PAPER BACKGROUND [0001} In the dis;;.'.ussion that fri!io,Ns, reference is made to certain products and/or methods.

However, the following references should not be construed as an admission that these products and/or methods constitute prior art.

Applicants expressly reserve the right to demonstrate that such pmducts and/or methods do not qualify as prior art. {0002] It has been well t:stablished knowledgt: as well as commercial practice to use glyoxalated polyacrylamidc in a variety of paper grades to provide paper with dry and temporary wet strength.

For instance. glyoxalated polyacrylamide can increase the initial wet strength of many household tissm~s that come into ,:ontact with wakr during their use.

Wet strength resins applied to paper are either of the ''permanent" or "ternporary" type; there terms relate to how long the paper retains its wet strength after immersion in water.

Wet stren!:,'th retention is a desirable property for some paper products.

However. paper products with permanent wet strength retention may be degradable only under severe conditions, therefore, wet strength retention can pose a disposal problem for such paper products.

Accordingly, temporary wet strength resins are desirable for sanitary or disposable paper uses for which initial wet strength followed by decay of the wet strength is desirable.

[0003] Methods fr,r preparing glyoxalatcd polyacrylamide polymers for use as temporary wet strength resins are known in the art. US Pat.

No. 3.556,932 discloses the synthesis and use of ionic water-soluble vinylamide polymers which are thermosetting due to a reacted content of glyoxaL US Pat.

No. 3,556,932 discloses polyacrylamidc polymers having, prior to glyoxalation, a molecular weight in the t·ange of7,000 to 20,000 Dalton.

The glyoxalated polymers, when applied to paper, are said to impart wet strength to paper. and the resulting paper is said to possess the property of losing a part of its vvet strength when soaked in water fi)r a moderate length of time.

Specificaily, it is shovvn that paper made with the disclosed glyoxalatcd copoiymers lose about 50% of their initial wet strength after being wetted for 30 minutes.

[0004] US Pat.

No. 4,605,702 discloses the synthesis and use of glyoxalated copolymers as temporary ,vet strength additives in papcrmaking.

The copolymers of US Pat.

No. 4,605.702, which are produced from ac11tlamide and a cationic comonomer. have a molecular weight (before glyoxalation) or about 500 to about 6000.

Exemplified 2 polymers range from l 700 to 5520 Dalton molecular weight (prior to glyoxalation). US Pat.

No. 4,605, 702 tem.:hes lhat paper products produced with the glyoxala.ted copolymers, upon immersion in neutral watt.·r at room temperature, exhibit wet strength losses of greater than 60'},,.

Wet strength loss for paper products prepared from the exemplified polymers ranges from 63.5 to 75.6%, after soaking in ni:utral water for 16 hours.

The copolymers of US Pat. :\lo. 4,605,702 are asserted to be distinguished over the US Pat.

No. 3,556,932 copolymers, because the wel strength imparted by the glyoxalated copolymers of US Pat.

No. 4,605,702 decays more quickly as compared to the glyoxalated copolymers disclosed in US Pat.

No. 3,556.932. US Pat.

No. 4,605,702 attributes the difforence in performance of these materials to differences in molecular ,veight of the copolymers before glyoxalation, where a lower molecular weight as used in US Pat.

No. 4,605,702, is shown to provide a faster rate of wet strength decay.

[0005] A drawba~:k of the glyoxalated copolymers disclosed in US Pat.

No. 4,605.702 is that their efficiency in building initial wet strength is significantly lower than the copolymers disclosed in US Pat.

No. 3,556,932.

Data presented in US Pat.

No. 4,605.702 illustrates that that disclosed glyoxalated copolymers must be added at a dosage of twofold to four-fold the dosage of the US Pat.

No. 3,556.932 giyoxalated copolymer to achieve the same level of initial wet strength in the paper prnducL

[0006] U.S.

Pat. '\lo. 7,727,359 discloses a thermosetting n~sin comprising a mixture of reaction products of a firs partially glyoxaiatcd polya...-:ry!amidc backbone, a second polyacrylamide backbone and a g!yoxal component.

The resin is asserted to produce fibrous substrates having temporary wet tensile propertie~; of the same order of magnitude as those disclosed in Li S Pat No. 4,605.702, but dry tensile strength intermediate to both US Pat.

Nos. 3,556,932 and 4.605,702.

[0007] The prior art thus shown that the decay rate of wet strength is inversely proportional to the molecular weight of the starting polymer. so that high rates of decay are only obtainable with low molecular ·weight starting polymers.

Thus, to produce glyoxalated copolymer additives that exhibit a high rate of wet strength decay rate, prior an processes are limited to the use of low molecular \veight cationic acrylamide starting polymers.

However, it has a!so been shown that efficiency of building wet strength is also inversely proportional to the molecular weight of the starting polymer used. such that low the molecular weight polymers result in additives with poor efficiency of building wet strength.

WO 2018/IJ-t675 PCT /IB 20 I 8/00006 7 3

[0008] There remains an on-going unmet need in tht! art for wr.:t strength polymel's with improved properties frw use in paper produds, such as toilet paper, faciai tissue, paper toweling and the like.

The present disclosure addresses this need, SUMMARY

[0009] The following summary is not an t:xtt:nsive overview. lt is intended to neither identif)· k~~Y or critical elements of the various embodiments, nor delineate their scope. (0010] The present disclosure is directed to glyoxalated vinylarnide polymers with high wet strength decay properties, which also exhibit a high efficiency of wet strength build.

The glyoxalated vinylamide polymers are prepared by a process using high molecular weight cationic vinylamide copolymers resulting in a composition comprising glyoxalatcd vinylamide polymer in an aqueous medium.

The gly(,;,rnlated vinylamide copolymer composition advantageously impart to a paper product comprising the glyoxalated vinylamide copolymer a unique tximbination of a high wet strength decay along with building wet strength with a high level of efficiency. A method of preparing the glyoxalated vinyl amide copolymers is provided, as well as methods of their use.

[0011] Provided is a cellulose reat'.tive glyoxalated copolymer composition comprising an aqueous medium and about 0.1 to about 4 weight %, about 0.25 to about 4 weight%, about l to about 3 weight%, or about 1.5 to 2.5 weight% of a cellulose reactive glyoxalated vinylamide copolymer, based total weight of the aqueous mediu1n, ,,vhercin: the glyoxalated vinylamide copolymer is obtained by reaction in an aqueous reaction medium of glyoxal and a cationic vinylamide copolymer: a dry weight of glyoxal:cationic copolymer in thl'. aqueous reaction medium ranging from about 5 to about 40 g!yoxal to about 95 to about 60 cationic vinylamide copolymer, about IO to about 30 glyoxal to about 90 to about 70 cationic vinylamide copolymer, from about 20 to about 25 glyoxal to about 80 to about 75 cationic vinylamidc copolymer. or about 23 glyoxal to about 77 cationic vinylamide copolymer; the aqueous reaction medium having a total solids concentration of from about 0.3 w about 3.0'%1, from about 0.5 to about 2.5%), from about 0.65% to about 2%, from about 0.75~/o to about 2'1/i,, from about 0.75 to about l.5'%, or from about 0.75 to about lo/,,; the cationic vinylamide copolymer having a weight average molecular weight of about 15,000 Daltons to about 80,000 Daltons, greater than 20,000 Daitons to about 80,000 Daltons, greater than 20,000 Daltons to about 60,000 Daltons, greater than 20,000 Daltons to about 50,000 Daltons, grealer than 20,000 Daltons to about 25.000 Daitons, about 20,500 Daltons, about 47,500 Daitons, or about 79,500 WO 2018/13-l675 PCT /IB20 J 8/00006 7 Dalt(ms, based on total weight of the cationic viny!amide copolymer before rem:tion with glyoxal, and comprised of about 5 to about 95 weight ~/o diallyldirnethyl ammonium halide monomer and about 95 to about 5 weight% acrylamide monomer, about 5 to about 25 weight '3/i; diallyldimethylammonium halide monomer and about 95 to about 75 weight% acrylamide monomer, abom 5 to about LS weight.% diallyldimethylam.monium halide monomer and about 95 to about 55 weight% acrylamide monomer, about 7.5 to about 92.5 weight ~✓.i diallyldirnethylammoniurn halide monomer an<l ab.out 92.5 to about 7.5 weight% acrylamide monomer. about 10 to about 90 weight% diallyldimethylammonium halide monomer and about 90 to about l O weight'% acrylamide monomer, about l 5 to abom 85 weight •11,;, diallyldimethylammonium halide monomer and about 85 to about 15 ,vcight %i at,rJlamide monomer, about 20 to about 60 weight '1/i) diailyldimethylammonium halide monomer and about 80 to about 40 weight% acrylarnide monomer, or about 20 to about 40 weight ~o diaHyldimethylammonium halide monomer and about 80 to about 60 weight % acrylamidc monomer, based on the total weight ofthe ,,ationic copolymer befr)re gly0xalation. [0012} Provided is the cellukN:: n:adive glyoxalatcd copolymer composition comprising an aqueous medium and about 0.1 to about 4 \veight 'Vi, of a cellulose reactive glyoxalated vinylamide copolymer, hased total weight of the aqueous medium. when~in the glyoxalatcd vinylamide copolymer is obtained by n·ai.:tion in an aqueous rem:tion medium of glyoxal and a cationic vinylamide copolymer, a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from about 5 to about 40 glyoxa! to ab1Jut 95 to about 60 cationic vinylamidc copolymer, the aqueous react.ion medium having a total solids curn:entration of from about 0.3 to about 3.0%,, the cationic vinylamide copolymer having a weight average molecular weight of abma 15,000 Dallons to about 80,000 Daltons based on total wdght of the .. :ationic vinyiamide copolymer before reaction with glyoxaL and comprised of about 5 to about 95 weight% dially!dimethyf ammonium halide monomer and about 95 to about 5 weight '?/o acrylamide monomer, based on the total weight of the cationic copolymer before glyoxa!ation. (00131 Provided is a method fbr preparing a cellulose reactive glyoxalated copolymer composition compri ~ing: reacting a substantially aquet)llS reaction mixture of a cationic vinylamide copolymer and glyoxal at a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from about 5 to about 40 giyoxal to about 95 to about 60 cationic viny!amide copolymer, the aqueous reaction medium having a total solids concentration of from about 03 to about 10%, the cationic vinylamide copolymer having a weight average molecular weight of about 15,000 Daltons to about 80,000 Daltons based on total weight of the cationic vinylamide copolymer before reaction with glyoxal and comprising about 5 to about 95 weight % diallyldimethyl ammonium halide monomer and about 95 to about 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation and at a reaction p1-1 o185 to 12. A cellulose reactive glyoxalated copolymer composition prepared by this method is also provided.

[0014] Further provided is a method of making paper comprising one of: (a) combining the glyoxalated copolymer composition of the disclosure and cellulose fibers; or (b) applying the glyoxalated composition of the disclosure to a wet or dry paper.

[0015] A paper strength additive or coating comprising the glyoxalated copolymer composition of the disclosure is provided.

Further provided is a coated with or comprising the glyoxalated copolymer composition of the disclosure. [0015a] In a broad aspect, the present invention relates to a cellulose reactive glyoxalated copolymer composition comprising an aqueous medium and 0.1 to 4 weight % of a cellulose reactive glyoxalated vinylamide copolymer, based total weight of the aqueous medium, wherein the glyoxalated vinylamide copolymer is obtained by reaction in an aqueous reaction medium of glyoxal and a cationic vinylamide copolymer, a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from 5 to 40 glyoxal to 95 to 60 cationic vinylamide copolymer, the aqueous reaction medium having a total solids concentration of from 0.5 to 2.5%, the cationic vinylamide copolymer having a weight average molecular weight of 20,500 Daltons to 46,100 Daltons based on total weight of the cationic vinylamide copolymer before reaction with glyoxal, and comprised of 5 to 95 weight % diallyldimethyl ammonium halide monomer and 95 to 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation. [0015b] In another broad aspect, the present invention relates to a method for preparing a cellulose reactive glyoxalated copolymer composition comprising: reacting a substantially aqueous reaction mixture of a cationic vinylamide copolymer and glyoxal at a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from 5 to 40 glyoxal to 95 to 60 cationic vinylamide copolymer, the aqueous reaction medium 5a having a total solids concentration of from 0.5 to 2.5%, the cationic vinylamide copolymer having a weight average molecular weight of 20,500 Daltons to 46,100 Daltons based on total weight of the cationic vinylamide copolymer before reaction with glyoxal and comprising 5 to 95 weight % diallyldimethyl ammonium halide monomer and 95 to 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation and at a reaction pH of 8.5 to 12.

[0016] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the disclosed compounds, compositions, and methods.

DESCRIPTION

[0017] There remains a need for wet strength polymers with improved properties for use in paper products, such as toilet paper, facial tissue, paper toweling, and the like.

The present disclosure addresses this need by provision of wet strength glyoxalated acrylamide polymers with high wet strength decay properties, which also exhibit a high efficiency of wet strength build, and a method for preparing same.

[0018] Glyoxalated acrylamide copolymers made by the disclosed process exhibit wet strength decay that is substantially equal to that achieved with copolymers disclosed in US Pat, No. 4,605,702, and additionally, the efficiency of initial wet strength development from the disclosed copolymers of the disclosed process is markedly higher than that demonstrated by the US Pat.

No. 4,605,702 copolymers, Further, the efficiency of wet strength development of the glyoxalated acrylamide copolymers prepared by the disclosed process is also higher than that of copolymers disclosed in US Pat.

No.3,556,932.

[0019] Methods of using the wet strength glyoxalated acrylamide copolymers in paper products is provided, along with the paper products so made.

WO 2018/13-t675 PCT /IB2018/00006 7 <, DE.FDHTIONS

[0020] As ust:d herein, each of the follo\-ving terms has the meaning associated with it in this section.

Additional definitions are present throughout the disdosure. {0021} The articles "a'' and "an'' are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical ol:>_iect of the article.

By way of example, "an element" means one clement or more than one element. [00221 The tenn ''about" will be understood by persons of ordinary skill in the art and will vary to some extent depending on the context in which it is used.

As used herein, the term ''about'' means that the number being described can deviatt~ by plus or minus five percent of the numher.

For example, "about 250 g'· means from 237.5-262.5 g.

When the term ·'about'' is used in a range. then the tower limit may be as much as minus 5% of the lower number and the upper limit may extend up to plus 5% of the upper number.

For example, a range of about l 00 to about 200 g indicaks a range that extends from as lovv as 95g up to 2!0 g. [00231 Ranges: tfmmghout this disclosure, various aspects of the disclosure can be presented in a range format. !t should be understood that the description in range fixmat is merely for convenience and brevity and should not be construed as an infiexibtc limitation on the scope of the disclosure.

Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range.

For example, description ofa range such as from l to 6 should be considered to have specifically disclosed subranges such as from l to 3, from I to 4, from l to 5, from 2 to 4, from 2 to 6, from 3 to 6 et<:., as well as individual numbers within that range, for example, L 2, 2. 7, 3, 4, 5, 5.3, and 6.

This applies regardless of the breadth of the range.

[0024] For the purposes of this disclosure, the product of lhe methods for preparing a cellulose reactive funetionaiized polyvinylamide adduct comprising reacting a substantially aqueous reaction rnixture of vinylamide copolymer and a cellulose reactive agent is referred to interchangeably as "adduct". "formed adduct'\ or "cellulose reactive fonctionalized polyvinylamide adduct."

[0025] The term "cellulose reactive agenf' refors to a compound that contains tvvo or more functional groups capable of fonning covalent bonds with cellulose, for example., a dialdehyde.

Glyoxal and glutaraldehyde are exemplary dialdehydes.

WO 2018/13-U,75 PCT /IB2018/00006 7 7

[0026] The terms ''vinylarnide" and ''acrytamide'' as used herein refer to any vinyl monomer containing an amide functionality including hut not limited to acrylamide, methacrylamide, N-methyl acrylamide. or any other substitutt'.d acrylamide.

[0027] The tcnns '·starting vinylamide copolymer," "starting acrylamidc copolymer," '·backbone vinylamide copolymer:' and "backbone acrylarnide copolymer'' refer to a polymer comprising vinyl monomers used in the preparation ofa cellulose reactive fonctionalizcd polyvinylamidc adduct.

[0028] The tenn ·'copolymer'' refers to a polymer formed from two or rnore monomers.

[0029] The term ··cationic copolymer'' refer:,; to lhc starting vinylamide copolymer bdi.1re glyoxalation.

Cationic copolymers can include non .. ionic and anionic monomer provided the aggregate charge of the copolymer is cationk.

[0030] For the purposes of this disclosure, the reaction of the pendant amide groups of the starting vinyiamide copolymers with glyoxa! (a type or a cellulose reactive agent) is referred to as a ''glyoxalation reaction"' or simply ''glyoxalation." The produ..:t of the glyoxalation reaction is referred to interchangeably as "glyoxaiatcd polyvinylamide," "g!yoxalated polyacrylamide," "glyoxalated poiyviny!amide copolymer,'' "glyoxalated polyacrylamidc polymer," "glyoxalated polyvinylamide adduct," and "glyoxalated polyacrylamidc adduct.''

[0031] As used herein. "G-PAM'' or "g-pam" is an abbreviation for glyoxalated polyacrylamide polymer. {0032] The term "aqueom, medium" or "aqueous reaction medium" refors to vvater or water comprising solvent, oils, and/or trace impurities.

Weights expre%ed in tem1s or "based on total weight of the aqueous medium" refer to the weight of the water or water comprising solvent, oils, andior trace impurities, and does not include the weight of additives, such as catalysts and reactants. £0033] The teml "substantially aqueous reaction mixture" refers to adduct formation carried out under conditions --where the presence of organic oi Is does not exceed the weight ofvinylamidc polymer.

For instance, adduct formation may be carried out under conditions where the totai weight of the organic oHs is less than 50 vvt. % of the vinylamide polymer, is less than about 20 wt.% of the vinylamide polymer, less than 10 \Vt. %) of the vinylamide polymer, le~s than about 5 wt. ~i. of the vinylamide polymer, or WO 2018/IJ-t675 PCT/182018/000067 less than about l -wt. % of the vinylamidc polymer.

Aitcrnativc!y, the substantially aqueous reaction medium is oil free.

[0034] The "total solids concentration'' of"ihe glyoxalation reaction mixture refers to "wL (%, of the vinylamidc copo!ym1.:r and glyoxal" before the reaction (i.e., before adduct formation) and is defined as fr,llows: Eq. I wht~rcin the "mass of the glyoxalation reaction mixture" includes the: solvents. [0035] [0036] ·'Wt, %, glyoxal consumed'' is based on total weight of giyoxal chargcd. ·'Molecular weight"' as used in this disclosure n::fors to the mean weight averagt~ molecular weight (l'vhv).

Unless otherwise noted, all molecular weight is measured in units of Daitons.

Molecular weight can be detennined by standard methods such as gel permeation chromatography ((WC).

For example, the weight average molecular weight may be determined by conventional calibration techniques using acetate buffor and the following hydrophilic po!yhydroxyl columns: two (2) PL Aquagcl-OH MIXED columns (7.5 mm x 300 mm, 8 rnh:mn) used in series. and a PL Aquagel-.QH Guard column (7.5mm x 50 mm, 8 micron).

All of these columns are available from Agilent Technologies.

Polyethylene oxide and polyethylene glycol standards may be us,~d to calibrate the three column set.

[0037] The terms "concentration of vinylamide copolymer" and "concentration of acrylamide copolymer'' rcfor to the concentration of the starting copolymer before reaction with the cellulose reactive agent (i.e., before adduct formation).

[0038] As used herein, "initial v,:et slrenglh development," ''efficiency of wet strength development," and '·wet strength build'. refer to the quantification of\vet strength imparted to paper resulting from the addition ofa ·wet strengthening polymer additive.

Initial wet strenb-.th as used herein can be mea,;ured by the standardized measurement technique described in the Examples.

[0039] As used herein, ·'temporary wet strength"' and ·'wet strength decay" re!cr to the change in residual ,vet strength imparted to paper resulting from the addition of a wet strengthening polymer additive. as a function of the amount of time that the paper has been re--welted.

For instance, a ·'S minute wet stren;,,rth decay" refers to lhc wet strength decay determined after the paper has been re .. wetted for 5 minutes.

Wet strength decay can be assessed by the measurement technique described in the Examples.

WO 2018/13-Hi75 PCT /IB2018/0000(, 7 9

[0040] As envisioned in the present disclosure ,,.,ith respect to the disclosed compositions of matter and methods, in one aspect, the ernbodiments of the disclosure comprise the components and/or s.teps disclosed therein. ln another asped, the embodiments of the disciosure consist essentially of the components and/or steps disclosed therein. ln yet another aspect, the embodiments ufthe disclosure consisi of the components and/or steps disclosed therein.

DETAILED DESCRIPTION [00411 The present disclosure provides a cellulose reactive glyoxalated vinylamide copolymer, as well as a composition comprising an aqueous medium containing the glyoxalated vinylamide copolymer.

Disclosed herein is a process for glyoxalating acrylamide copolymers found unexpectedly to enable the use of relatively high rnolecular weight (molecular weight measured prior to glyoxalation) copolymers in paper product, while still pmviding a high rate of wet strength decay over time in tht~ paper prodw;:t. A combination of: I) staxiing vinylamidc copolymer molecular weight: 2) vinyiamide copolymer concentration in a reaction solution; 3) ratio of cationic acrylamide polyrner to dialdehyd1.: cross-Hnker; and 4) reaction pH, have been found to provide this unique combination of prnpe11ies of high wet strength efficiency and high wet strength de;;.'.ay over time.

Features of the disclosed process include using starting acrylamide copolymers with molecular weight in the range of l 5,000 to 80,000 Daltom, reacting the starting vinyiamide wpolymf.:rs with glyoxal at a total solids concentration (weight% of starting copolymer and glyox.al in reaction mixture) bet,veen 0.3 and 3.0(}i,, a dry weight range of 95:5 to 60:40 (copolymer:glyoxai), and running the glyoxalation reaction at a pH between 8.5 and !2.

The reaction can be nm for a time of from 10 to 300 minutes.

Starting copolymc1·

[0042] The starting vinylamide copolymers that arc used in adduct formation (such as glyoxalation) can be obtained by methods of polymer synthesis known to those skilled in the art such as free radical or redox catalysis polymerization of a vinylamide monomer, and one or more co-monomers.

The vinyiamidc copolymer is cationic.

Crns~•iinking agents \vith multiple po!ymerizable viny! functionalities can also be included in the fonnulations to impmi structure to the backbone polymer. A chain transfi.~r agent, such as sodium hypophosphitc, can be used to control the molecular weight of the poiymer molecules. as well as to introduce branching.

WO 2018/13-t<,7:'i PCT/IB2018/000067

[0043] The cationic copolymer before glyoxalation has a v,cight average molecular weight of about l 5,000 to about 80,000 Daltons, including about 15,000 to about 75,000 Dallons, about l 5,(100 to about 70,000 Daltons, including about 15,000 to about 65,000 Daltons, including about 15,000 to about 60,000 Daltons, about 15,000 to about 55,000 Daltons, about 15,000 to about 50,000 Daltons, about 15,000 to about 47,500 Daltons, about 15,000 to about 40,000 Daltons, about 15,000 to about 35,000 Daltons, about J 5,000 to about 30,000 Daltons, about l 5,000 to about 25,000 Daltons; about 20,000 to about 80,000 Daltons, including about 20,000 to about 75,000 Daltons, about 20,000 to about 70,000 Daltons, about 20,000 t0 about 65,000 Daltons, about 20,000 to about 60,000 Daltons, about 20,000 to about 55,000 Daltons, about 20,000 to about 50,000 Daltons, about 20,000 tu about 47,500 Daltons, about 20,000 to about 40,000 Daltons, about 20,000 to about 35,000 Daltons, about 20,000 to about 30,000 Daltons, about 20,000 to about 25,000 Daitons; or greater than 20,000 lo about 80,000 Daltons, including greater than 20,000 to about 75,000 Daltons, greater than 20,000 to about 70,000 Dalwns, greater than 20,000 to about 65,000 Daltons, greater than 20,000 to about 60,000 Dah(ms, greater than 20,000 to about 55,000 Daltons. greater than 20,000 to about 50,000 Daltons, greater than 20,000 to about 47,500 Daltons, greater than 20,000 to about 40,000 Daltons, greater than 20,000 to about 35.000 Daltons, greater than 20,000 to about 30,000 Daltons. or greater than 20,000 to about 25,000 Daltons.

An exemplary cationic copolymer has a molecular weight before glyoxa!ation of greater than 20,000 to about 80,000 Daltons, about 20,500 Daltons, about 46. l 00 Dal tons or about 79,500 Daltons.

[0044] The cationic copolyrner for glyoxalation is a cationic copolymer comprising at least two difforcnt monomer units: vinylamidc, e.g,, acrylamide monomer, and a diallyldirnethylammonium halide monomer.

An exemplary cationic copolymer comprises vinylamide monomer and dially!dimethy!arnmonium halide monomer, or contains only vinylamide monomer and dial!y!dimethylamrnonium halide monomer.

The halide ofthe diallyldimethylammonium halide monomer can indude bromine (Br). chlorine (Cl), iodine ( I), or fluorine (F).

An exemplary diallyldimethylarnmonium halide monomer is diallyldimethylammonium chloride (DADMAC).

[0045] The cationic copolymer comprises about 5 to about 95 weight % diallyldimethylammoniurn halide monomer and about 95 to about 5 weight%, acrylamide monomer, about 7.5 to about 92.5 weight% diallyldimethylammonium halide monomer and about 92.5 to about 7.5 weight%, acrylamide monomer, about IO to about 90 weight WO 20l8/l3-Hi75 PCT /IB2018/00006 7 II '% diallyldimethylammonium halide monomer and about 90 to about 10 ,,,,eight 'Yo acrylamide monomer, about 15 to about 85 weight% diallyldimethy!ammonium halide monomer and about 85 to about 15 weight %i acrylamide monocm:r, about 20 to about 60 weight ~·'o diallyldimethylammonium halide monomer and about 80 to about 40 weight% acrylamide monomer, or about 20 to ab(,ut 40 weight% diallyldimethy!ammonium halide monomi.:r and about 80 to about 60 weight% acrylamide monomer, based on total weight of the cationic copolymer before glyoxalation.

An exemplary cationic copolyrner comprises about 5 to about 25 weight ':Vi, diallyldimethylammonium halide monomer and about 95 to about 75 weight% acrylamide monomer, or about 5 to about l 5 weight% diaHyldimethylammonium halide monomer and about 95 to about 55 weight% acrylamide monomer. [0046J The cationic copolymer can include one, two, three, or more cationic, non-- cationic, or anionic monomer units.

Cationic copolymers can include non-ionic and anionic monomer provided the aggregate charge of the copolymer is cationic.

[0047] Suitable cationic: monomers or potentiaily cationic monomers include <liallyldialky! amines, 2-vinylpyridine, 2-(dialkylamino)alkyl(meth)acrylates, dialkylamino alkyi(meth) acrylamides, including acid addition and quaternary ammonium salts thereof.

Specific examples of such cationk monomers or potentially cationic monomers are (meth)ai..:ryloyloxy ethyl trimethylammonium chloride (dimethyl amino ethyl(meth)acrylak, methyl chloride quaternary salt), 2-vinyl-N-methylpyridinium chloride, (p-viny lphcnyl)-trimethylammonium chloride, (meth)acrylate 2- ethyltrirnethy lammonium chloride, l-methacryloyi-4-methyi piperazine, Mannich polyacrylamides i.e., polyacryiamide reacted with dimethy!amine fom1aldehyde adduct to give the N•(dimethyl amino methyl) and (meth}acrytamido propyltrimethyl ammonium chloride.

[0048] Suitable anionic monomers can be selected from vinyl acidic material such as acrylic acid, methacrylic acid, ma!eic acid, ally! sulfonic acid, vinyl sulfonic acid, itaconic acid, fumaric acid, potential!y anionic monomers such as ma!eic anhydride and itaconic anhydride and their alkali metal and ammonium salts, 2-acrylamido-2-methylpropancsulfonic acid and its salts. sodium styrene suifonate and the like.

[0049] Suitable non-ionic monomers other than the vinylamide can be selected from the group consisting of (meth) acrylic esters such as octadecyl(meth)acrylate, ethyl acrylate. butyl acrylate, methylmethacrylatc, hydroxyethyl(meth)acry!ate and 2- WO 2018/13-4675 PCT /IB2018/00006 7 12 ethylhexylacry!ate; N-alkyl acrylamides, N-octyl{meth)acrylamide, N-tert-butyl acrylamide, l\-vinylpyrrolidone, N,J\:- dialkyl(rneth)acrylamides such as N,N'-dimcthyl acrylamide; styrene. vinyl acetale, hydroxy alkyl r~crylates and methacrytak: such as 2- hy<lroxy ethyl acrylate and acrylonitrik.

[0050] The cationic copolymer can be crosslinked, branched or othenvise structured or linear..

For example, the cationic copolymer can be linear, crosslinkcd. chain-transferred, or noss!inked & chain-translerred (structured).

[0051] Crosslinking agents arc usually polyethylcnically unsaturated crosstinking agents.

Examples are methylene bis(meth)acry!arnide, triallylammonium chloride; tetraally! ammonium chloride, poly(ethylene glycol) diacrylate; poly(ethy[ene gl.ycol) dimethacrylate; N-vinyl acrylamide; divinylbenzene; tetra(ethylene glycol} diacrylate; dimethylallylaminoethylacrylate ammonium chloride; diallyloxyacetic acid, Na salt: dialiylrn:tylamide; trimethyllpmpane ethoxylate triacryalte; N-allylacrylamide Nmethylallyiacrylamide, pentaerythrito! triacrylate and combinations thereof.

Other systems for crosslinking can be used instead of or in addition to these.

For instance, covalent crosslinking through pendanl groups can be achieved by the use of ethylenically unsaturated epoxy or silane monomers, or by the use of polyfi.mctional crosslinking agents such as silane1>, epoxies, polyvalent metal compounds or other knmvn crossiinking systems.

Total Solids Concentration in reaction solution

[0052] The glyoxalation reaction of the polyvinylamidc is carried out at concentrations oft.he polyvinylamide where gelation is prevented.

Moreover. in the method of the disclosure, the total solids concentration (total solids being weight of starting vinylamide copolymer and glyoxai) of the reaction solution is about 0.3 to about 3% by weight total solids, at about 0.5 to about 2.5% by weight total Sl)lids, at about 0.65 to about 2'Vi, by weight total solids, at about 0.75 to about 2%, by weight total solids, at about 0.75 to about l .5'% by weight total solids. or at about 0. 75 to about I'% by weight total solids.

An exemplary total solids concentration in the glyoxalation reaction solution is ab,)ut l %.

Ratio of cationic starting acrylamide polymer to dialdchyde t~ross-linker

[0053] The glyoxalatcd copolymer is obtained by reaction in an aqueous reaction medium of a di) weight ratio of glyoxal:cationic copolymer ranging from about 5 to about 40 glyoxal to about 95 to about 60 cationic copolymer (i.e., about 5:95 to about 40:60), including from about IO to about 30 glyoxal to about 90 to about 70 cationic copolymer WO 2018/13-t675 PCT /IB2018/00006 7 13 (Le., about 10:90 to about 30:70), including from about 20 to about 25 giyoxa! to about 80 to about 75 cationic copolymer (i.e., about 20:80 to about 25:75).

The weight percent of glyoxal and cationic polymer is based on the total weight of the dt)' reactants before the glyoxalation step. {0054} An exemplary aqueous reaction medium contains 0. 77'1/'o by weight copolymer solids, 0.23% by weight glyoxal on a dry basis, and 99'Vi, deionized water, corresponding to a dry weight ratio of g!yoxal:cationic copolymer of 23:77.

Reaction pH

[0055] Base addition or changing the pH to above 7 is the most common method of catalyzing the glyoxalation reaction.

In the method of the disclosure, the reaction pH is a pH of8.5 to 12, a pH 9 to l 1.5, a pH of9.5 to l Lor a pH of9.5 to l0.5.

An exemplary pH for the reaction is l 0.5.

[0056] The duration of the reaction necessary to obtain the desired product (e.g., 0. l to 4 wt. % glyoxalatcd ~:npo!ymcr or 0.25 to 4 wt. '% glyoxalated copolymer in the aqueous composition) will vary depending on concentration, temperature and pH, as well as other factors kmnvn in the art to aftcct the rate ofglyoxalation.

The glyoxalation reaction of the present disc!osun! is run for IO to 300 minutes, 25 to 250 minutes, 50 to 200 minutes, I 00 to 200 minutes, or 100 to l 50 minutes.

An exempiary reaction time is 120 minutes.

[0057] The glyoxa!ation reaction is carried om at a temperature ranging from 15 to 35"C, from 20 to 30°C, or from 20 to 25°C.

An exemplary reaction temperature is 2()CC.

[0058] The glyoxalation reaction can be carried out in batch or continuous mode.

For instance. the reaction can be carried out in a in a continuous reactor with pH measuremem capability at the papem;aking site.

[0059] Conventional additives which can be added to the glyoxalation reaction are cht~lating agents to remove polymerization inhibitors, pH adjw,ters, initiators, buffers, surfactants or combinations tht'.reof.

The disclosed proct'.SS can be practiced without any one or all of such conventional additives.

Monitoring of Glyoxalated Copolymer l•ormation

[0060] Viscosity is typically measured during the reaction using the UL adapter fi.)r a BROOKFIELD LV series viscometer.

The UL adapter has no spindle number.

Only one setting is possible.

The base of the adapter cup is removed and the assembly is placed directly into the reaction mixture.

Viscosity measurements are automatically recorded WO 2018/134(i7:- PCT /182018/0000(,7 14 every second during the !ength of the catalyzed reac:tion.

The viscometer is set to a speed of60 rpm and the temperature of the reaction mixture is maimained at 25" C.

[0061] The glyoxalated copolymer formation may a !so be monitored by monitoring the consumption of glyoxal using methods known in the art.

For exam pk:, one sueh method may include the method disclosed by l\;JitcheL R.EJ, et al. "The use oCG!rard-T reagent in a rapid and sensitive method for measuring glyoxal and certain other odicarbonyl compounds," Ana(vticaf Biochemishy, Volume 8], Issue 1 .

July 1977, Pages 4 7-56.

The percent residual glyoxal can be determined from 2 wt.%, aqueous solutions of the glyoxalated polyvinylamides.

Residual glyoxal is removed from the glyoxalated polymer by dialysis through a 3500 MWCO membrane tubing.

Ten millifaers (ml) or dialyzed sample is derivatized by adding 2.0 ml of o-(2,.3,4,5.6 Pematluorobenzyl)hydroxyamine h:;drochioride (6.6 mg/ml} for approximately 2 hours. rhe glyoxal is then extracted from the dialysis solution using l: l hexane-diethyl ether.

Analysis of the extract can be completed by gas chromatography on an HP 5890 Gas Chromatograph (GC) #6 instrument using a DB--5 15m, 0.53mm i.d., 1.5~,m df(column length, internal diameter, and film thickness, respectively) column.

Once the residual glyoxal is dctennincd and the amount of pre-reaction glyoxal is known, the percent glyoxal consumed can be calculated.

GJyoxalatcd cormlymer composition

[0062] The glyoxalated copolymer composition of the disclosure contains the glyoxaiated copolymer in an amount of about O. l w about 4 weight'~~- including about 0.25 to about 4 weight~'<>, about ! to about 3 weight%,, or about 1.5 to 2.5 weight ~'o, based on total weight of the aqueous medium.

When the amount of glyoxalated copolymer in the glyoxalated copolymer composition exceeds about 4 weight '!Ii,, then gelation becomes a problern, !0063] The glyoxalar.ed copolymer composition of the disclosure i::; a thcnnos~tting resin.

The glyoxalated copolymer composition can comprise more than one type of glyoxaiated vinylarnide copolymer or one or rnore other glyoxalated polymers useful for temporary wet strength paper applications.

Alternatively, the glyoxa!ated copolymer composition of the disclosure contains suhstantially only the glyoxalatcd copolymer of the disdosure as the polymeric themwsetling resin component. {0064] The glyoxalated copolymer composition has a viscosity of equal to or less than I 00 centipoise (cP), a visc0sity from about 5 to ahout J 00 d', a viscosity less than or equal to 30 cP, a vi'>cosity from about 30 to about 5 cP, a viscosity from abom 25 t(, abt,ut l O cP, WO 2018/134675 PCT /IB2018/0000<,7 a viscosity less than or equal to 25 cP, or a viscosity less than 25 to about 5 cP, as measun:,d using a Brookfo.~ld viscometer. [0065} The disclosure provides a cellulose reactive glyoxalated copolymer composition comprising an aqueous medium and about O. l to about 4 vveight %, about 0.25 to about 4 weight~;,. about 1 to about 3 "vcight %, or about l .5 to 2.5 weight% of a cellulose reactive glyoxalated vinylamide copolymer, based total weight ofthe aqueous medium, wherein: the glyoxalated vinylamide copolymer is obtained by reaction in an aqueous reaction medium of glyoxal and a cationic vinyiamide copolymer: a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from about 5 to about 40 glyoxa! to about 95 to about 60 cationic vinylamidc copolymer, about IO to about 30 glyoxal to about 90 to about 70 cationic vinylamide copolymer. from about 20 to about 25 glyoxal to about 80 to about 75 cationic vinylamide copolymer, or about 23 glyoxal to about 77 cationic vinylamidc copolymer: the aqueous reaction medium having a total solids concentration of from 0.3 to 3.0'h. from 0.5 to 2.5~o, from 0.65'11,, to 2%. from 0.75°/o to 2%, 0.75 to l .5(>->, or from 0.75 to 1%; the cationic vinylamide copolymer having a weight average molec.ular weight of about 15,000 Daltons to about 80.000 Daltons, greater than 20,000 Dalton;; to about 80,000 Daltons, greater than 20,000 Daltons to about 60,000 Dal tons, greater than 20,000 Daltons to about 50,000 Daltons, greater than 20,000 Daltons to about 25,000 Da!tons, about 20,500 Daltons, about 4 7.500 Daltons, or about 79,500 Daltons, based on total weight of the cationic vinylamide copolymer before reaction with glyoxal, and comprised of about 5 to about. 95 weight%, dially!dimethy! ammonium halide monomer and about 95 to about 5 weight '1/o acry!amide monomer, abom 5 to about 25 weight% dia!lyldimethylammonium ha!ide monomer and about 95 to abom 75 weight% acrylamide monomer, about 5 to about 15 weight% dia!lyldimethylammonium halide monomer and about 95 to about 55 ,vcight ?'ii acrylamide monomer, about 7.5 to about 92.5 weight o..,;, diallyldimethylammonium halide monomer and about 92.5 lo about 7.5 weight%, acry!amide monomer, about 10 to about 90 weight % diallyldimethylammonium halide monomer and about 90 to about 10 \Veight O.lii acrylamkfo monomer, about 15 to about 85 wdght •% diallyt<limethylammonium halide monomer and about 85 to about 15 weight 'h1 acrylamide monomer, about 20 to about 60 weight (}i, diatlyldimethylarnmonium halide monomer and about 80 to about 40 weight~,;. acrylamide monomer, or about 20 to about 40 weight 1 1/0 diallyldimethylammonium halide monomer and about 80 to about 60 weight % acrylamide monomer, based on the total WO 20 I8/JJ-t675 PCT /JB2018/000067 vveight of the cationic copolymer befixe glyoxalation, wherein the acrylamide monomer is acrylamide, methacrylamide, N-methyl acrylamide, or a substituted acrylamidc Use of Glyoxalated copolymer composition

[0066] The glyoxahued copolymer composition of the disclosure is useful as a high molecular weight temporary wet strength resin additive for paper.

Accordingly. the present disclosure further provides a method of making paper, which includes a step of combining a glyoxalated copolymer composition of the disclosure and cellulosic fiber slurry or applying a glyoxalated copolymer composition to a wetidry web paper. ln the method of making paper, the sequence in which the cellulose fibers are combined with the glyoxalatcd copolymer composition is not particularly limited.

For example, the mt:thod can include adding the glyoxalated copolymer composition to an aqueous suspension of cellulose fibers; adding cellulose fibers ao the glyoxalatcd copolymer composition; adding the glyoxalatcd copolymer composition and cellulose fibers to an aqueous solution; and/or reacting in an aqueous reaction medium comprising cellulose fibers a dry ,veight ratio of g{yoxal:cationic copolymer ranging from about 5 :95 to about 40:60 to fom1 the glyoxalated copolymer, wherein the glyoxalated copolynH~r is about 0. 1 to about 4 weight ~/,, based on total weight of the aqueous reaction medjum.

Thus, the disclosure provides a method for preparing paper with improved wet strength properties comprising the steps of: a) providing an aqueous slurry ofcellulosic fibers; b) adding the glyoxalated copolymer composition of the disclosure to the aqueous slurry: c) forming a web from the aqueous slurry formed in step b); and d) drying the web, to frmn a paper product having improved efficiency of initial wet strength development as well as incrt·ascd wet strength decay over time.

[0067] The glyoxa!atcd copolyrner l'.(irnpos1tion can be added to the thick or thin stock.

When added to the thin stock, it may be added before the fan pump. A substantial amount of wet strength is imparted when as [ittle as about O. l O ,vt. 0/4, of the glyoxalaled copolymer, based on dry fiber weight of the glyoxalated copolymer is added to the furnish.

For example, suitable dosages include about 0.10 to about 40 (0.05-20 kg/metric ton) pounds dry polymer per ton of dry furnish, about l to about 20, (0.5-10 kg/metric ton), about l to about 10 (0.5- 5 kg/metric ton), about l to about 8 (0.5--t kg/metric ton) pounds. or 1.5 to about 6 (1.0-3 kg/metric ton) pounds dry polymer per ton of dry furnish.

[0068] Application t1f the glyoxalated copolymer compositiun to wet/dry paper may be accomplished by any conventional means.

Exampks include but are not limited to size WO 2H18/IJ-Ui75 PCT/IB2018/000067 17 press, padding, spraying, immersing, printing or curtain coating.

Accordingly, the disclosure also provides a method for providing paper with improved wet strength propeities comprising the steps of: a) spraying, immersing. coating or otherwise applying glyoxalatcd ...:opolymcr composition of the disclosure onto a wet web or wet paper; and b) drying the coated wet web or wet paper, to fr.inn a paper product having improved cffid.:.~ncy of initial wet strength development as well as increased wet strength decay over time.

[0069] The disclosure includes a paper product containing a cellulose reactive glyoxalated t'.opolymer composition comprising an aqueous mt.:dium and about 0.1 to about 4 weight~;.,, about 0.25 to about 4 weight 'Vi,, about i to about 3 weight %1, or about 1.5 to 2.5 weight %1 of a cellulose reactive glyoxalated vinylamide copolymer, based wtal weight of the aqueous medium, when:,in: the glyoxalated vinyiarnide copolymer is obtained by reaction in an aqueous reaction rnedium of glyoxa! and a cationic vinylamide copolymer; a dry weight of glyoxal:cationic copolymer in tht~ aqueous reaction medium ranging from about 5 to about 40 glyoxal to about 95 to about 60 cationic vinylamide copolymer, about IO to about 30 glyoxal to about 90 to about 70 cationic vinylamide copolymer, from about 20 to about 25 g!yoxal to abom 80 to about 75 cationic vinyiamide copolymer, or about 23 g!yoxal to about 77 cationic vinylamidc copolymer; the aqueous reaction medium having a total solids concentration of from 0.3 to 3.0%, from 0.5 to 2.5':/o, from 0.65% to 2';/41, from 0, 75% to 2%, fl. 75 to l .5~o, or from 0.75 to 1 %; the cationic vinylamidc copolymer having a weight average molecular weight of about 15,000 Daltons to about 80,000 Dalions, greater than 20,000 Daltons to about 80.000 Daltons, greater than 20,000 Dal tons to about 60,000 Daltons, !::,'Tealer than 20,000 Daltons to about 50,000 Da!tons, greater than 20,000 Daltons to about 25,000 Daltons, about 20,500 Daltons, about 47,500 Dalton:s, or about 79,500 Daltons, based on total weight of the cationic vinylarnide copolymer before reaction with glyoxaL and comprised of about 5 to about 95 weight '¾) diailyldimethyl ammonium halide monomer and about 95 to about 5 weight% acrylamide monomer, about 5 to about 25 weight ~'o diallyldimethylammonium halide monomer and about 9::'i to about 75 weight% acrylamide monomer, about 5 to about l 5 ,ve1ght l}o diallyldimethylammonium halide monomer and about 95 to about 55 weight %1 acrylamidc monomer, about 7.5 to about 92.5 weight 01£1 diallyldimethylammonium halide monomer and about 92.5 to about 7.5 weight ~o acrylamide monomer. about IO to about 90 weight % diaHyldimethylammonium haiide WO 2018/IJ-l67S PCT /IB2018/00006 7 18 monomer and about 90 to about l O weight 'Yi; acrylamide monomer, about i 5 to about 85 weight ?/4, diallyldimethylammoniurn halide monomer and about 85 to aboui I 5 weight% acrylamide monomer, about 20 to about 60 weight% dially!dimethylammonium halide monomer and about 80 to about 40 weight% acryiamide monomer, or about 20 to about 40 weight%, dia!lyldimethylammonium halide monorm!r and about 80 to about 60 weight % acrylamide monomer, based on the tmal weight of the cationic copolymer before glyoxalation, wherein the acrylamidc monomer is acryiamide. methacrylamide, N-methy! acrylamide. or a substituted acrylamide.

[0070] The disclosure includes a paper product containing the glyoxalated copolymer composition, wherein the giyoxyiated copolymer is the reaction product forrn by reacting a substantially aqueous reaction mixture ofa cationic vinylamide copolymer and glyoxal at a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from about 5 to about 40 g!yoxal to about 95 to about 60 cationic vinylamide copolymer, the aqueous reaction medium having a total solids lXmcemration of from 0.3 to 3.0%. the cationic vinylamide copolymer having a v,,eight average molecular weight of about 15,000 Daltons to about 80,000 Da!tons based on total weight of the cationic vinylamide copolymer befrmi reaction ,vith glyoxal and comprising about 15 to about 85 weight'% diallyldimethyl ammonium halide monomer and about 85 to about 15 weight 1),·'i, acrylamidc monomer, based on the total weight of the cationic copolymer before glyoxalation and at a reaction pH or 8.5 to 12.

EXAMPLES

[0071] The products, compositions. and methods of making and using are further described in detail by reference to the fbllowing experimental examples.

These exampks are provided for purposes of illustration oniy, and are not intended to be iimiting unless otherwise specified.

Thus, the products, compositions. and methods of the disclosure should in no way be construed as being limited to the following exampks, but. rather, should be construed to encompass any and all variations which become evident as a result ofthe teaching provided herein.

Example l Synthesis and Glyoxalation of Starting Copolyme,· Hackbones

[0072] A cationic copolymer containing 8.6 weight% diallyldimethylammonium chloride monomer and 9 l .4 weight'% acrylamide were prepared as follows.

[0073] A suitable one liter reaction vessel, equipped with a reflux condenser, overhead stirrer, thermocouple, and nitrogen sparge, was charged with 253.4 parts of water, 2 L8 WO 2018/13-1675 PCT /182018/00006 7 19 parts of63.5% diallyldimethylammonium chloride, 0.91 parts adipic acid, l.75 parts sodium hypophosphite, and 2. l parls ammonium persulfate.

The reacwr contents wen.~ heated to 30°C and sparged with nitrogen for 30 minutes.

Next.. two eont.inuous feeds - Feed One and Feed Two - were started simultaneously, each lasting for 120 minutes.

Feed One eontaint~d a mixture of 276.5 pans of 53%i acrylamide. 77 parts of deionized water, 0.32 parts of potassium bromate, and 2.17 parts ofCHEL@ DPTA-4 l (BASF Corporation, New Jersey; aqueous solution ofpentasodium diethylenetriaminc-pentaacetate).

Feed T,:vo contaim.:d I A parts of sodium bisulfite, 15 parts deionized water, and 1. 75 pa1is of sodium hypophosph[te.

Once the two foeds were started, an exotherm ensued, and the temperature of the reactor contents rose to 75°C, and was maintained at this temperature for the remainder of the reaction by applying cooling or healing to the system as needed.

After !20 minutes, and the feeds were cornplete, the temperature of the reaction mass was raised to 85°C, and 2 parts of ammon.ium persulfate dissolved in 4 7 parts of deionized water was added to the reactor contents over a two minute period, which was followed by a 120 rninute hold at 8SCC.

Finally, the polymer was cooled and collected.

The resultant copolymer had a molecular weight of20,500 Daltons (Copolymer A).

[0074] The proct?dure follow·ed to product~ Copolymer A ,vas repeated two additional times, \vith the only change being the quantity of sodium hypophosphite added to the initial reactor charge and to the feed Two.

[0075] When the sodium hypophosphite charge was OA9 parts added separately to both the initial reactor charge and the Feed Two, then the resultant copolymer had a molecular weight of 46, l 00 Daltons (Copolymer B). [0076] \Vhcn the sodium hypophosphite charge was 0.26 parts added separately to both the inilial reador charge and the Feed T·wo, then the resultant copolymer had a molecular weight of 79,400 Daltons (Copolymer C).

[0077] The copolymer backbones were then glyoxalatcd. A hornogeneous glyoxalation reaction solution as made from deionized water, Copolymer A and 40% glyoxa1, such that the reaction solution was 0.77% by weight copolymer solids. 0.23% by \veight glyoxai on a dry basis and 99.0% deionized water.

The total solid:, concentration of the reaction solution was l %,.

Dropwise addition ofa 5% sodium hydroxide solution was made to the glyoxalation solution, which was under continuous mixing, to raise the pH of the solution to I 0.5, and the pH was held at l 0.5 and temperature \Vas held at 20°C for 120 minutes.

At the end of 120 minutes, the pH was lowered to a solution pH of3.5 WO 2018/13-l<,75 PCT /182018/00006 7 by the dropwise addition of sulfuric acid.

The final glyoxalated copolymer sample ("gpam ! ") was collected.

[0078] The same glyoxalation procedure as destTibcd above was followed to produce glyoxalatcd copolymers from Copolymer 8 and Copolymer C, which final products were collected and desi,gnated ''g-pam 2'' and "g~pam 3," respectively Example 2 Comparative Glyoxalated Copolymer I [00791 A sample of comparative prior art glyoxalated polyacryiamide was produced according to the method described in Exam pk ! of U.S.

Pat.

No. 4.605, 702.

The rnolernlar weight (Mw I of this initial copolymer was 3.070 Daltons.

The sample is designated herein as ·'Comparative g-pam 1 ,. l(xample 3 Comparative Glyoxalated Copolymer 2 [0080J A second sample of comparative prior art g-pam ls produced according to the method dcs~~rib~~d in Example i ofIJ.S.

Pat.

No. 3,556,932.

The molecular ,veight (Mw) of this initial copolymer was l 2,080 Daltons.

The sample is designated herein as "'Comparative g-pam 2." Example 4 Comparntive Glyoxalated Copolymer 3

[0081] A third comparative g-pam was produced by g!yoxalating a sample of Copoiyrner A (20,500 IJaltons) from Example I.

Copolymer A was glyoxalated by the method set fi.xth in Example I of U.S.

Pat.

No. 3,556,932.

The final glyoxalatcd material v,as cG!lccted and is designated h(~rein as "Comparative g-pam 3." Example 5 Paper Products

[0082] An aqueous., pulp slurry was synthesized from a 70:30 ratio of hardwood to softv,ood fibers. beaten to 380 Canadian Standard Freeness (CSF) and diluted to 0.5%, consistency. with pH of6.9.

Aliquots of the pulp slurry v,:ere collected. placed under overht:.ad stirring. and glyoxalated copolym-:r solutions were added to the pulp slurry tt) achieve final addition levels of 5, IO and 20 pounds of g-pam (dry weight) per ton of oven dry pulp.

Once additit)n of the g-parn to the pulp slurry was completed, the mixture \Vas then stirred for 30 seconds to perm Et absorption of the g-pam onto the fiber in the aqueous pulp slurry.

Each aliquot of pulp slurry with g-parn additive produced a 200 square centimeter round handsheet with a basis weight of 60 grams per square meter.

The formed vveb was then pressed between paper blotters, and dried on a steam-heated rotary drum dryer at a temperature of240°F to produce a handsheet.

WO 2018/134675 PCT /182018/0000<, 7 21 [0083] \Vet tensile strength of the finished paper was measured according to TAPPI Test Method T456.

Each tensile strength value is the average of 3 measurements and reported in pounds per inch (ibf/in).

The "'5 minute Wet Tensile Strength" was determined by soaking the treated papt:!r in water at pH 7.0 fix 5 minutes and ihen measuring the wet tensile strength.

The'% Decay is calculated as (initial wet tensile stren,gth - 5 minute wet tensile strength)/ initial wet tensile strength.

The results are set forth in Table l.

[0084] Dosage Table l Initial Wet Tensile Strength (!bf/in} 5 lb/ton ! 0.89 0.46 48.93% ! g-pam l : ,.-u,,_.,,,_,._,,._,,,,,_. '-''-" ~ '"""'°"'-"' ._, .... ,,,, .. ..;.,, ''"' , ... • • > .__. • • "'" "" • -..-: '""'''""" """"""""""""'"} i 10 lb/ton ! 1.39 j 0.87 ! 37.66%, ; ' ! I 20 !biton l 2.20 i 1.08 L 50.86% i ! I . ! 5 lb/ton [ Comparative ! ...................... .. \ i lO lb/ton l g-pam ! ; ............. ;-----;--- .. ·····+· , ! 20 ,btton ! !' Comparative i. f !!-pam 2 ! i - I 5 lb/ton l0lbiton 20 !b/ton ~--- 0.49 0.49 0.26 47.36% 0.2.s ••••••1····4cfsTif ..... 1 i ••• ···~--. -•,.-- ••• ·-·~ ..... ---. .......... •'•'•' ·-~--. . . . ; 0.68 0.3 7 46.02%, ; 0.87 LI I l.21 i 0.51 0.63 0.84 4!.34%, 43.23'}0 ··-··· .......... ,,t 30.48%, i I 5lb/ton , l.32 0.9! 3Ll3'·Vi, i Comparative ~.. .. . . ......... +-- .................................... ..................... , ........................... , i ' l O !b/ton I l.94 1.52 21.77'}{, • ![ g··pam 3 ,;_· " 20 lb/ti;n i ... --i,i<:i°-·····-- ... i:ii' : 27.7%-, • , ..... ~ ... ,.,, ____!_ ~~--~ .... ,. .. ._~,----•••-.. •---•--•J ... ,.,~•----------_..,,_.,,.,, __ ,H :"""""'"-" •~-----•----•••••--: •----~• ,_.._,,,,,.,_, The data for Comparativ~ g-pam 2 il!ustratl:'S the gund initial ,vet strength imparted by the polymer of US Pat.

No. 3,556.932, as well as the poor wet tensile strength decay.

The data fiJr Comparative g-pam l illustrates the improved wet tensile strength decay for a lower mole;,;ular weight starting polymer (relative to US Pat.

No. 3.556,932), as well as (he poor initial wet strength imparted by a polymer oflJS Pat.

No. 4, 605,702.

[0085] In notable contrast, the data for g-pam 1 illustrates an initial wet strength as good, or better, than that of a polymer according to US Pat.

No. 3,556,932, while also having wet tensile strength decay as good, or better, than lhat of a polymer according to US Pat.

No. 4,605,702.

Thus, the glyoxalated vinylamide copolymer of the present WO 2018/134(,75 PCT /I B2018/0000(, 7 22 disclosure unexpectediy possesses both efficient initial wet strength build and a high rate of wet tensile strength decay.

[0086] Comparative g-pam 3 illustrates that g!yoxalating Copoiymer A with the glyoxalation method of US Pat.

No. 3, 556,932, improved the initial wet tensile strength of the paper, relative to the Comparative g-pam 2, however, the paper has markedly poorer wet tensile strength decay relative to both Comparative g·•pam 2 and g-pam L Thus. compared to prior art methods or glyoxalation, the glyoxa!ation method of the present disclosure unexpectedly provides glyoxalated copolymers imparting superior wet strength properties to paper.

[0087] Mullen Burst Strength of the finished paper was measured according to TAPP! Test Ivlethorl T403.

The "30 minute Wet Burst Stn.~ngth" was determined by soaking the treated paper in water at pH 7.0 for 30 minutes and then measuring the ·wet burst strength.

The%; Decay is calculated as (initial "vet burst strength - 30 minute wet burst strength) i initial wet burst strength.

The results are set forth in Table 2. """"""""""""""""""""""""'""""""""""""""'"f"""''""''"'"'"· ......... ,.,,,.,,, ... , ... ..

Comparative gpam l g-pam l l I i Dosage i 5 lbiton /. ......................................... ;.. 10 lb/ton i 20 lb/ton ! 0 !b/ton 20 lb/ton Table 2 Initial \Vet Burst Strength (Kpa*m2/g) 0.5987 0.8590 1.9569 0.6646 1.3702 2.2255 0.7545 • 30 minute Wet ! • Wet Burst Burst Strength (Kpa*m2/g} 0.2259 0.3209 •••••• •n••., ••~n~••••••••••'-'"'' • '••- 0.9706 Decay(%) 62% 63% 50% 60'% 63% 5 lb/ton 55% lO lb/ton 20 lb/ton .................... 0.3424 g-pam 2 1.6364 0.8440 .. .. .... ···----~-- ~~---·-····--·-····--: -~--------~--~~~~-...... ~ : ~----··-··· ... -~.-. ··~--~-. ~-~ --~----~ 2.6607 1.5849 i 40')i, 5 lb/ton 0.9733 0.4919 49'Yo g-pam 3 2.0527 3 l'Vi, {0088] The data for ''Comparative g-pam l" illustrates a good wet burst .;;trength decay fr)r this additive. hmNever it also shows that poor initial wet strength is imparted by the polymer of US Pat.

No. 4, 605,702.

The data for "'g-pam l '' shovvs equal performance in 23 wet burst decay to “Comparative g-pam 1”, while advantageously demonstrating a notably higher initial wet burst strength result.

The data for “g-pam 2" and g-pam 3" shows the impact of using higher molecular weight polymers in the process of the disclosure, specifically that additives made from higher Mw polymers show a higher initial wet burst strength result, and a lower level of wet burst strength decay.

[0090] While the products, compositions, methods of making them, and their methods of use have been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations may be devised by others skilled in the art without departing from the true spirit and scope of the described products and methods.

The appended claims are intended to be construed to include aft such embodiments and equivalent variations.

Claims (16)

1. 24 What is claimed is: 1. A cellulose reactive glyoxalated copolymer composition comprising an aqueous medium and 0.1 to 4 weight % of a cellulose reactive glyoxalated vinylamide copolymer, based total weight of the aqueous medium, wherein the glyoxalated vinylamide copolymer is obtained by reaction in an aqueous reaction medium of glyoxal and a cationic vinylamide copolymer, a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from 5 to 40 glyoxal to 95 to 60 cationic vinylamide copolymer, the aqueous reaction medium having a total solids concentration of from 0.5 to 2.5%, the cationic vinylamide copolymer having a weight average molecular weight of 20,500 Daltons to 46,100 Daltons based on total weight of the cationic vinylamide copolymer before reaction with glyoxal, and comprised of 5 to 95 weight % diallyldimethyl ammonium halide monomer and 95 to 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation.
2. 2. The cellulose reactive glyoxalated copolymer composition according to claim 1, wherein the cationic vinylamide copolymer has a weight average molecular weight of 20,500 Daltons, based on total weight of the cationic vinylamide copolymer before reaction with glyoxal.
3. 3. The cellulose reactive glyoxalated copolymer composition according to claim 1, wherein the dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranges from 23 glyoxal to 77 cationic vinylamide copolymer.
4. 4. The cellulose reactive glyoxalated copolymer composition according to claim 1, obtained by reaction carried out at a reaction pH of 8.5 to 12.
5. 5. The cellulose reactive glyoxalated copolymer composition according to claim 1, obtained by reaction carried out for 10 to 300 minutes.
6. 6. The cellulose reactive glyoxalated copolymer composition according to claim 1, obtained by reaction carried out at a temperature from 15 to 35°C.
7. 7. A method for preparing a cellulose reactive glyoxalated copolymer composition comprising: reacting a substantially aqueous reaction mixture of a cationic vinylamide copolymer and glyoxal at a dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranging from 5 to 40 glyoxal to 95 to 60 cationic vinylamide copolymer, the aqueous reaction medium having a total solids concentration of from 0.5 to 2.5%, the cationic vinylamide copolymer having a weight average molecular weight of 20,500 Daltons to 46,100 Daltons based on total weight of the cationic vinylamide copolymer before reaction with glyoxal and comprising 5 to 95 weight % diallyldimethyl ammonium halide monomer and 95 to 5 weight % acrylamide monomer, based on the total weight of the cationic copolymer before glyoxalation and at a reaction pH of 8.5 to 12.
8. 8. The method for preparing a cellulose reactive glyoxalated copolymer composition according to claim 7, wherein the cationic vinylamide copolymer has a weight average molecular weight of 20,500 Daltons, based on total weight of the cationic vinylamide copolymer before reaction with glyoxal.
9. 9. The method for preparing a cellulose reactive glyoxalated copolymer composition according to claim 7, wherein the dry weight of glyoxal:cationic copolymer in the aqueous reaction medium ranges from 23 glyoxal to 77 cationic vinylamide copolymer.
10. 10. The method for preparing a cellulose reactive glyoxalated copolymer composition according to claim 7, wherein the reaction is carried out at a reaction pH of 9.5 to 10.5.
11. 11. The method for preparing a cellulose reactive glyoxalated copolymer composition according to claim 7, wherein the reaction is carried out for 10 to 300 minutes.
12. 12. The method for preparing a cellulose reactive glyoxalated copolymer composition according to claim 7, wherein the reaction is carried out at a temperature from 15 to 35°C.
13. 13. A cellulose reactive glyoxalated copolymer composition prepared by the method according to any one of claims 7-12. 26
14. 14. A method of making paper comprising one of: (a) combining the glyoxalated copolymer composition of any one of claims 1-6 and cellulose fibers; or (b) applying the glyoxalated composition of any one of claims 1-6 to a wet or dry paper.
15. 15. A paper strength additive or coating comprising the glyoxalated copolymer composition of any one of claims 1-6.
16. 16. A paper coated with or comprising the glyoxalated copolymer composition of any one of claims 1-6.