KR102630029B1 - Highly efficient wet strength resins from novel crosslinkers - Google Patents

Abstract

Strength resin and methods of making and using the same. Strength resins may include polyamines that are partially crosslinked with bridging moieties and have azetidinium ions. Bridging moieties may be derived from functionally symmetric crosslinkers. Functionally symmetric crosslinking agents may include diisocyanates, 1,3-dialkyldiazetidine-2,4-dione, dianhydrides, diacyl halides, dienones, dialkyl halides, or any mixtures thereof.

Description

Highly efficient wet strength resins from novel crosslinkers

The disclosed embodiments generally relate to strength balance. More specifically, the above embodiments are strength resins that may include polyamines partially cross-linked with bridging moieties and have azetidinium ions, wherein the bridging moieties may be functionally derived from symmetrical cross-linkers. , relates to strength resins and methods of making and using them.

Paper is a sheet material containing small, discrete fibers that are interconnected. Fibers are generally formed into sheets on a fine screen from a dilute water suspension or slurry. Paper is typically made from cellulose fibers, although synthetic fibers are sometimes used. Paper products made from untreated cellulose fibers quickly lose their strength when they become wet, i.e., they have very little “wet strength.” The wet strength of conventional paper is only about 5% of its dry strength. The wet strength of paper is defined as the paper's resistance to rupture or disintegration when wet with water. See U.S. Patent No. 5,585,456. To overcome the above weaknesses, various processing methods of paper products are used.

Wet strength resins applied to paper are either of the “permanent” type or the “temporary” type, defined by how long the paper retains its wet strength after immersion in water. While maintaining wet strength is a desirable characteristic in packaging materials, paper products with this characteristic present disposal problems because they are degradable only under undesirably harsh conditions. Some resins impart temporary wet strength and are suitable for sanitary or disposable paper applications; These resins often suffer from one or more drawbacks. For example, the wet strength of the resins is generally an order of magnitude lower (about one-half of the level achievable with permanent-type resins), the resins can be easily invaded by mold and slime, and/or the resins are in dilute solutions. It can only be manufactured as.

Conventional resins, which can provide permanent wet strength to paper, typically combine polyamidoamine polymers such as A and epichlorohydrin ( B ) to form polyamidoamine (PAE)-epichlorohydrin resins. epi").

Conventional resin synthesis utilizes the difunctional nature of epichlorohydrin to utilize epoxy and chlorine groups for both crosslinking and creation of quaternary nitrogen sites. In these conventional resins, the asymmetric functional group of epichlorohydrin is cross-linked intramolecularly or intermolecularly (cross-linked) with another polyamidoamine molecule, which then cyclizes to produce the secondary amine of its epoxy group, and then the azetidinium functional group. Reaction with the pendant chlorohydrin moiety leads to ring opening. Therefore, the first step of the reaction between epi B and polyamidoamine prepolymer A occurs through ring opening of the epoxy group by the secondary amine group of the prepolymer skeleton at a relatively low temperature. A new functionalized polymer C with chlorohydrin pendant groups is produced, and the process typically results in little significant change in the prepolymer molecular weight.

The second step involves two competing reactions of pendant chlorohydrin groups: 1) intramolecular cyclization to produce a cationic azetidinium chloride functional group, with no increase in molecular weight observed; and 2) an intermolecular alkylation reaction to crosslink the polymer, significantly increasing its molecular weight. The results of both reactions are illustrated in PAE-epichlorohydrin resin structure D. In reality, the alkylation, intramolecular cyclization and crosslinking reactions of epichlorohydrin are occurring simultaneously, but at different rates.

The finished wet strength polymer product contains a significant amount of quaternary azetidinium chloride functional groups, along with small amounts of residual pendant chlorohydrins, as illustrated in Structure D , and 3-carbon bridged groups with 2-hydroxyl functional groups. Contains. The product may also contain significant amounts of the epi chlorohydrin hydrolysis products 1,3-DCP, and 3-CPD.

The relative rates of the three main reactions in this conventional method, namely pendent chlorohydrin formation (ring opening), cyclization to azetidinium ion groups (cationization), and cross-linking (intermolecular alkylation), when carried out at room temperature, are: Approximately 140:4:1, respectively. Accordingly, pendant chlorohydrin groups form very rapidly from the ring-opening reaction of epichlorohydrin epoxide and secondary amines in the prepolymer. The first step is performed at low temperature (e.g., approximately 25°C to 30°C).

In the second step, the chlorohydrin group cyclizes relatively slowly to form a cationic azetidinium group. Even more slowly, crosslinking occurs, for example, by: 1) a tertiary amine of a pendant chlorohydrin group, for example, reacting with a secondary amine moiety and/or 2) a pendant chlorohydrin moiety. and intermolecular alkylation of tertiary amines.

To remain practical for minimum reaction cycle times, conventional manufacturing processes typically require the reaction mixture to be heated to increase the reaction rate, for example from about 60°C to about 70°C. Typically, the reaction is also performed at high solids content to maximize reactor throughput and provide a finished wet strength resin at the highest solids possible to minimize shipping costs. High concentrations favor slower, intermolecular reactions. Under these high temperature and high concentration conditions, the reaction rates between intramolecular cyclization and crosslinking become competitive. Accordingly, one problem encountered in conventional manufacturing processes is that the crosslinking reaction rate becomes sufficiently fast that the desired viscosity endpoint (molecular weight) is achieved at the expense of azetidinium ion group formation. If the reaction is continued beyond the desired viscosity endpoint to produce higher levels of azetidinium groups, the reaction mixture will similarly gel and form a solid mass.

Because both high azetidinium group content and high molecular weight are useful for maximum wet strength efficiency of the PAE resin, azetidinium group formation and crosslinking are preferably maximized without gelling the product or providing the product to gel during storage. These conditions, coupled with the requirement for high solids to minimize transportation costs, are limiting aspects of the formation of higher efficiency wet strength resin products.

Accordingly, there is a need for improved strength resins, such as those for imparting appropriate levels of wet strength to paper products, and methods for making and using the same.

summary

Strength resins and methods of making and using the same are provided. In at least one example, the strength resin may include a polyamine that is partially crosslinked with bridging moieties and has azetidinium ions. Bridging moieties may be derived from functionally symmetric crosslinkers. The functionally symmetrical crosslinker may be or include a diisocyanate, 1,3-dialkyldiazetidine-2,4-dione, dianhydride, diacyl halide, dienon, dialkyl halide, or any mixture thereof. can do.

In at least one example, a method of making a strength resin may include the reaction of a polyamine and a functionally symmetric crosslinking agent to produce a partially crosslinked polyamine. The functionally symmetrical crosslinker may be or include a diisocyanate, 1,3-dialkyldiazetidine-2,4-dione, dianhydride, diacyl halide, dienon, dialkyl halide, or any mixture thereof. can do. Partially crosslinked polyamines can be reacted with epihalohydrin to produce strength resins with azetidinium ions.

In at least one example, a method of strengthening paper may include contacting fibers with a strength resin. The strength resin may be or include a polyamine partially crosslinked with bridging moieties and has azetidinium ions. Bridging moieties may be derived from functionally symmetric crosslinkers. Functionally symmetrical cross-liners include diisocyanate, 1,3-dialkyldiazetidine-2,4-dione, dianhydride, diacyl halide, dienon, dialkyl halide, or any of these. It may be a mixture or may include the above.

details

Strength resins, such as wet strength resins, methods for making strength resins, and methods for treating paper to impart strength using strength resins are provided. The use of functionally symmetric (“symmetric”) cross-linkers and, optionally, monofunctional modifiers and the reaction of partially cross-linked polyamines with epihalohydrins, such as epichlorohydrin, to obtain functionally symmetric cross-linkers. Novel strength resins are provided, such as wet strength resins, with improved properties and/or improved flexibility in the separation of the reaction of polyamines into distinct stages, their synthesis. In addition to providing generally improved wet tensile development over current technology, the products and methods can provide higher azetidinium ion content, additional degree of reactive functionalization, maximized molecular weight, and/or good storage stability. there is.

Polyamine crosslinking differs from the “cationization” processes of halohydrin-functionalization and cyclization, features that provide substantial flexibility in tailoring cationic functionality, molecular weight, and/or other resin properties. The functionally symmetric crosslinking agents and optional monofunctional modifiers used to effect crosslinking and functionalization of the polyamine may be different from the reagents used to impart a cationic charge to the resin. Specifically, the reaction of a polyamine with a functionally symmetric crosslinker may be separate from the reaction of a partially crosslinked polyamine with an epihalohydrin. For example, functionally symmetric (or simply “symmetrical”) crosslinkers are used in the first step, which can provide substantial control over the crosslink structure and properties of partially crosslinked prepolymers, such as polyamine or polyamidoamine prepolymers. It can be. The step of imparting a cationic charge to the resin, the “cationization” process, can utilize any epihalohydrin, such as epichlorohydrin, to generate azetidinium ion functionality.

The process for making the strength resin can also reduce the amount of epichlorohydrin by-product when compared to the amount typically found in conventional polyamidoamine-epichlorohydrin strength resins not made by the process. For example, strength resins include 1,3-dichloro-2-propanol (1,3-DCP or “DCP”) and 3-chloropropane-1, which generally involve epichlorohydrin wet strength resin synthesis. and have substantially reduced levels of 2-diols (3-CPD or “CPD”; also MCPD for monochloropropane diol).

In some examples, a method of making a strength resin, e.g., a wet strength resin, may include reacting a polyamine, which may be referred to herein as a polyamine prepolymer, with a functionally symmetric crosslinker to produce a partially crosslinked polyamine. there is. As such, polyamines can be partially crosslinked with bridging moieties and the bridging moieties can be derived from functionally symmetric crosslinkers. Epihalohydrins can be added to partially crosslinked polyamines to produce halohydrin-functionalized polymers. Halohydrin-functionalized polymers can be cyclized to form resins with azetidinium moieties. Likewise, the strength resin may be or include a polyamine partially crosslinked with bridging moieties and may have azetidium ions or moieties.

If desired, the method may further comprise reacting the polyamine with a minor amount of a monofunctional modifier comprising one secondary amine-reactive moiety. When a polyamine is reacted with an insufficient amount of a monofunctional modifier, the reaction may occur before, during, or after the polyamine is reacted with the symmetric crosslinker, or at different combinations of times.

In one example, the polyamine may have the structure:

wherein R can be alkyl, hydroxyalkyl, amine, amide, aryl, heteroaryl or cycloalkyl. In structure P , w can be an integer from 1 to about 10,000. As provided in the Definitions section, R groups such as “alkyl” or “hydroxyalkyl” are intended to provide a convenient explanation under which conventional rules of chemical valency apply; Accordingly, R of structure P may be written as alkyl or hydroxyalkyl, which is intended to reflect that the "R" group is divalent and may alternatively be written as alkylene or hydroxyalkylene.

The most widely used and most effective wet strength resin products are generally derived from polyamidoamine (PAA) prepolymers, which are reacted with epichlorohydrin to form so-called polyamidoamine-epichlorohydrin (PAE) resins. Therefore, when the polyamine is or includes a polyamidoamine prepolymer, the resin is, but is not limited to, a polyamidoamine-based system, but is applicable to any amine-containing polymer (polyamine) such as structure P and other amine-containing polymers. It is intended to do so.

Epichlorohydrin is a difunctional compound with different, therefore "asymmetric", chemical functional groups, epoxy and chlorine groups. The asymmetric functional group allows for ring opening when epichlorohydrin reacts with an epoxy group with a secondary amine and then with a pendant chlorohydrin moiety, which is used both for: 1) to produce a cationic azetidinium functional group; intramolecular cyclization; or 2) intermolecular cross-linking of the polymer to increase molecular weight. Epichlorohydrin Resin Structure D illustrates the results of both reactions in polyamidoamine-epichlorohydrin (PAE) resin.

The present disclosure provides increased levels of cationic charge (higher charge density), additional functionality, optimized or maximized molecular weight, high solids content, and/or lower DCP and CPD from improved azetidinium ion content. Formulations and processes for making strength resins, such as wet strength resins, are provided. In one aspect, the disclosed method separates resin synthesis into two distinct and controllable steps. First, a medium molecular weight, crosslinked prepolymer is constructed, prepared by reaction of a polyamine prepolymer with a functionally symmetric crosslinker. Unlike the function of the asymmetric crosslinker epichlorohydrin, the symmetric crosslinker of the present disclosure utilizes the same moiety to react with both prepolymer secondary amine groups to effect crosslinking. If desired, monofunctional groups can be used before, after, or during the crosslinking step to impart additional functionality to the prepolymer without crosslinking functionality. The second step utilizes epichlorohydrin to impart cationic functionality without being required for any cross-linking function, by using reduced amounts of epichlorohydrin to maximize azetidinium ion formation in the polymer. This process stands in contrast to conventional practice, which is limited by the need to optimize the simultaneous competing azetidinium ion formation and cross-linking mechanisms.

polyamine prepolymer

Any type of polyamine (polyamine prepolymer) can be used as a precursor to the wet strength resins disclosed herein. The polyamine may be or include primary and/or secondary amine moieties linked to at least one spacer.

By way of example, in one aspect, a polyamine, which may be referred to herein as a polyamine prepolymer, may have the structure:

R in the formula may be, for example, alkyl, hydroxyalkyl, amine, amide, aryl, heteroaryl or cycloalkyl. In structure P , w can be an integer from 1 to about 10,000, 1 to about 5,000, 1 to about 3,000, 1 to about 1,000, 1 to about 100, or 1 to about 10. These "R" groups, such as "alkyl", are intended to provide a convenient description of a designated group derived from the formal removal of one or more hydrogen atoms (as required for the particular group) from the parent group. Therefore, the term "alkyl" in structure P will apply the conventional rules of chemical valency to apply, but for example, two hydrogen atoms from an alkane (two hydrogen atoms from one carbon atom or two hydrogen atoms from two different carbon atoms). It will include an “alkanediyl group” formed by the formal removal of one hydrogen atom). Such alkyl groups, unless otherwise specified, may be substituted or unsubstituted groups, may be acyclic or cyclic groups, and/or may be linear or branched. A “hydroxyalkyl” group includes one or more hydroxyl (OH) moieties substituted for “alkyl” as defined.

In the above aspects and unless otherwise indicated, R of structure P may be an alkyl moiety that is linear (straight chain) or branched. Moiety R may also be a cycloalkyl, i.e., a cyclic hydrocarbon moiety having from 1 to about 25 carbon atoms. For example, R can have 1 to 25, 1 to 20, 1 to 15, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Also by way of example, R can have 2 to 10, 2 to 8, 2 to 6, or 2 to 4 carbon atoms. In a further aspect, R is C ₁ moiety, C ₂ moiety, C 3 moiety, C ₄ moiety _{, C 5 moiety, C 6 moiety, C 7 moiety, C 8 moiety , C 9 moiety} , C _{10 moiety} , C ₁₁ moiety, C ₁₂ moiety, C ₁₃ moiety, C 14 moiety, C ₁₅ moiety, C ₁₆ moiety, C ₁₇ moiety, C ₁₈ moiety, C ₁₉ moiety , C ₂₀ moiety, C ₂₁ moiety, C ₂₂ moiety, C ₂₃ moiety _{, C 24 moiety, C 25 moiety, C 26 moiety, C 27 moiety, C 28 moiety , C 29 moiety} , it may be a C ₃₀ moiety.

In the polyamines having the structure P exemplified above , R can also be a poly-primary amine, such as polyvinyl amine and copolymers thereof. Examples of poly-primary amines that can form R in structure P include, but are not limited to, the structures below, as well as copolymers with olefinic and other unsaturated moieties, where n is from 1 to about 25. Can be an integer:

Alternatively, n can be an integer from 1 to about 20, 1 to about 15, 1 to about 12, 1 to about 10, or 1 to about 5. In another aspect, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 , may be 23, 24, or 25.

Suitable polyamines (polyamine prepolymers) for use in preparing the resins of the present disclosure include, but are not limited to, diethylenetriamine (DETA), triethylenetetramine (TETA), aminoethyl piperazine, tetraethylenepentamine, pentaethylene. Containing hexamine, N-(2-aminoethyl)piperazine, N,N-bis(2-aminoethyl)-ethylenediamine, diaminoethyl triaminoethylamine, piperazynethyl triethylenetetramine, etc. polyalkylene polyamines, such as polyethylenepolyamine. Also useful in preparing polyamines for use in preparing the resins of the present disclosure are ethylene diamine, low molecular weight polyamidoamines, polyvinylamine, polyethyleneimine (PEI) and other unsaturated copolymerizable monomers such as vinyl acetate and vinyl alcohol and vinyl amines. Contains copolymers of

According to one aspect of the polyamine prepolymer P , w is in a numerical range corresponding to the polyamine prepolymer Mw mole number of about 2,000 to about 1,000,000. The Mw molecular weight of the polyamine prepolymer P may also be from about 5,000 to about 750,000, from about 7,500 to about 500,000, from about 10,000 to about 200,000, from about 20,000 to about 150,000, or from about 30,000 to about 100,000.

polyamidoamine prepolymer

Types of polyamidoamine prepolymers can also be used as precursors for wet strength resins according to the present disclosure. Polyamidoamine prepolymers are prepared by reacting a dicarboxylic acid with a polyalkylene polyamine having at least two primary amine groups and at least one secondary amine group in a process to form long chain polyamides containing repeating groups as disclosed herein. It can be manufactured by. In one aspect, the polyamidoamine prepolymer may have the structure:

where R ¹ is (CH ₂ )m where m is 2, 3, 4, or 5; R ² is (CH ₂ )n where n is 2, 3, or 4; w is 1, 2, or 3; p is a numerical range corresponding to the polyamidoamine prepolymer Mw molecular weight of about 2,000 to about 1,000,000. The Mw molecular weight may also be from about 5,000 to about 100,000, from about 7,500 to about 80,000, from about 10,000 to about 60,000, from about 20,000 to about 55,000, or from about 30,000 to about 50,000.

In one aspect, the polyamidoamine prepolymer may have the structure:

where R ³ is (CH ₂ ) _q where q ranges from 0 to 40; r is a numerical range corresponding to the polyamidoamine prepolymer Mw molecular weight of about 2,000 to about 1,000,000. Similarly, the Mw molecular weight can also be from about 5,000 to about 100,000, from about 7,500 to about 80,000, from about 10,000 to about 60,000, from about 20,000 to about 55,000, or from about 30,000 to about 50,000. Thus, in the structure (CH ₂ ) _q , q can also be from 0 to about 40, from 0 to about 35, from 0 to about 30, from 0 to about 25, from 0 to about 20, from 0 to about 15, from 0 to about 12, from 1 to about 40, 1 to about 35, 1 to about 30, 1 to about 25, 1 to about 20, 1 to about 15, 1 to about 12, 1 to about 10, 1 to about 8, or 1 to about 6. You can.

In another aspect, the polyamidoamine prepolymer can have the structure:

where n is 1 to 8; p is 2 to 5; m is from 0 to 40, and similar molecular weight ranges apply.

As disclosed, suitable polyamidoamines are generally prepared by the reaction of polyamines such as polyalkylene polyamines with dicarboxylic acids (diacids), or their corresponding dicarboxylic acid halides or diesters. Suitable polyamines include the polyamines disclosed herein (polyamine prepolymers), which can be used as precursors to the wet strength resin itself. For example, useful polyamidoamines include ethylenediamine itself, diethylenetriamine (DETA), triethylenetetramine (TETA), aminoethyl piperazine, tetraethylenepentamine, pentaethylenehexamine, N-(2-amino) Suitable polyalkylene polyamines, such as polyethylenepolyamine, including ethyl)piperazine, N,N-bis(2-aminoethyl)-ethylenediamine, diaminoethyl triaminoethylamine, piperazinethyl triethylenetetramine, etc. Polycarboxylic acids such as succinic acid, glutaric acid, 2-methylsuccinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, 2-methylglutaric acid, 3 , 3-dimethylglutaric acid and tricarboxypentane such as 4-carboxypimelic acid; Cycloaliphatic saturated acids such as 1,2-cyclohexanedicarboxylic acid, 1-3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and 1-3-cyclopentanedicarboxylic acid; unsaturated aliphatic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, aconitic acid and hexane-3-dioic acid; unsaturated alicyclic acids such as Δ4-cyclohexenedicarboxylic acid; Aromatic acids such as phthalic acid, isophthalic acid, terephthalic acid, 2,3-naphthalenedicarboxylic acid, benzene-1,4-diacetic acid, and heteroaliphatic acids such as diglycolic acid, thiodiglycolic acid, dithiodiglycolic acid, iminodiacetic acid, and It can be prepared by reaction with methyliminodiacetic acid. In general, diacids and their related diesters of the formula RO ₂ C(CH ₂ ) _n CO ₂ R where n = 1 to 10 and R = H, methyl, or ethyl and mixtures thereof are preferred. Adipic acid is readily available and often used.

Other suitable polyamines may include JEFFAMINE® polyetheramines, available from Huntsman. JEFFAMINE® polyetheramines contain primary amino groups attached to the ends of the polyether backbone. The polyether backbone is based on propylene oxide (PO), ethylene oxide (EO), or mixed EO/PO. Different JEFFAMINE® products may contain different backbone segments and have been able to vary the reactivity provided by the interference of the primary amine or through secondary amine functionality. Lower molecular weight JEFFAMINES®, such as JEFFAMINE® D-230, as well as higher molecular weight JEFFAMINES®, such as JEFFAMINE® D-2000, may be acceptable.

symmetry crosslinking agent

In general, the secondary amines of the polyamine may be reacted with one or more symmetric crosslinking agents. In one example, reaction of a secondary amine of a polyamine and a symmetrical crosslinker can provide greater control throughout the crosslinking process and an intermediate crosslinked prepolymer with a higher molecular weight than the starting prepolymer. The viscosity endpoint and therefore the molecular weight of the intermediate can be easily pre-determined and controlled, at least in part, by the amount of symmetrical crosslinker used. The cross-linking reaction can advance to an endpoint as the cross-linking agent is consumed and can stop when the cross-linking agent is consumed. A reduced and measurable amount of secondary amine functionality will remain available for further functionalization.

In the cross-linking step, the polyamine may be reacted with an insufficient amount of symmetrical cross-linking agent, based on the total amount of secondary amine available for cross-linking, to provide a partially cross-linked polyamine. Accordingly, partially crosslinked polyamines have higher molecular weights than polyamines, even though they are intermediates in the process and retain some of the secondary amine groups present in the polyamines. In a further aspect, the partially crosslinked prepolymer retains a majority of the secondary amine groups present in the polyamine because less than 50% of the stoichiometric amount of symmetrical crosslinker may be used.

Based on the prepolymer repeat unit with a single secondary amine applied to the reaction, and the symmetric crosslinker with two reactive moieties, the stoichiometric reaction of prepolymer to crosslinker requires a 2:1 molar ratio and, in practice, prepolymer to crosslinker A molar ratio of 2:1 or higher is used. In one aspect, the symmetric crosslinker to prepolymer molar ratio is greater than 0%, but less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, 20% of the stoichiometric ratio of crosslinker to prepolymer. %, less than 15%, less than 10%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.75%, or less than 0.5%. These values reflect the combined molar amounts when using crosslinkers with greater than 1 symmetry.

Polyamines can be reacted with symmetric crosslinking agents in the presence or absence of water. In one example, the polyamine can be reacted with a symmetric crosslinking agent in an aqueous medium, such as water or a water-containing mixture. In another example, the polyamine can be reacted with a symmetric crosslinking agent in a non-aqueous medium, such as a non-aqueous solvent or diluent. In another example, a polyamine can be reacted with a symmetric crosslinking agent in the absence of any other liquid medium, whether aqueous or non-aqueous. Non-aqueous media, such as solvents or diluents, may be non-reactive with the polyamine, symmetric crosslinker, and/or partially crosslinked polyamine. When a polyamine is reacted with a symmetrical cross-linking agent in the absence of any other liquid medium or in a non-aqueous medium to produce a polyamine partially cross-linked with bridging moieties, the polyamine partially cross-linked with bridging moieties can be dissolved in any water. It can be kept free or substantially free or can be mixed with water.

Examples of symmetric crosslinking agents include, but are not limited to, one or more diisocyanates, one or more 1,3-dialkyldiazetidine-2,4-dione, one or more dianhydrides, one or more diacyl halides, one or more dienones, one or more It may include one or more dialkyl halides, or any mixture thereof. Other examples of symmetric crosslinking agents include, but are not limited to, one or more di-acrylate compounds, one or more bis(acrylamide) compounds, one or more di-epoxide compounds, one or more polyazetidinium compounds, one or more N,N'- methylene-bis-methacrylamide, one or more poly(alkylene glycol) diglycidyl ethers, or any mixtures thereof. In at least one example, the symmetric crosslinking agent is at least one of the following: (1) diisocyanate, 1,3-dialkyldiazetidine-2,4-dione, dianhydride, diacyl halide, dienon, and dialkyl halide. and may include at least one of the following: (2) di-acrylate compound, bis(acrylamide) compound, di-epoxide compound, polyazetidinium compound, N,N'-methylene-bis-methacrylamide. , and poly(alkylene glycol) diglycidyl ether.

Diisocyanates can be unblocked or blocked. Exemplary unblocked diisocyanates include, but are not limited to, 4,4'-methylene diphenyl diisocyanate (methylene diphenyl diisocyanate, MDI); Toluene-2,4-diisocyanate (toluene diisocyanate, TDI); 1,6-hexane diisocyanate (hexamethylene diisocyanate, HDI); 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethyl-cyclohexane (isophorone diisocyanate, IPDI), or any mixture thereof. Exemplary blocked diisocyanates include, but are not limited to, bis-caprolactam blocked 4,4'-methylene diphenyl diisocyanate; 4,4'-methylene diphenyl diisocyanate bis(2-buanone oxime) adduct, bis-(3,5-dimethylpyrazole) blocked 4,4'-methylene diphenyl diisocyanate, or these It may include any mixture of. Commercially available blocked diisocyanates include, but are not limited to, TRIXENE® BI products available from Baxenden Chemicals such as TRIXENE® BI 7641, 7642, 7674, 7675, 7950, 7951, 7960, 7961, 7963, and 7982, and Rudolf RUCO-Guard products available from the Group may include such as RUCO-Guard XCR, XTN, FX 8011, FX 8021, NET, TIE, and WEB.

Exemplary 1,3-dialkyldiazetidine-2,4-dione include, but are not limited to, 1,3-diazetidine-2,4-dione; 1,3-dimethyl-1,3-diazetidine-2,4-dione; 1,3-diethyl-1,3-diazetidine-2,4-dione; 1,3-diphenyl-1,3-diazetidine-2,4-dione; Or it may include any mixture thereof. Exemplary dianhydrides include, but are not limited to, pyromellitic dianhydride; Ethylene glycol bis (trimellitic anhydride); 4,4'-bisphenol A dianhydride, or any mixture thereof. Exemplary diacyl halides include, but are not limited to, oxalyl chloride, oxalyl bromide, succinyl chloride, benzene-1,2-dicarbonyl dichloride, benzene-1,2-dicarbonyl bromide, phthaloyl chloride, or It may include any mixture thereof. Exemplary dienones include, but are not limited to, 1,7-octadiene-3,6-dione; bis(2-propen-1-one)-(1,4-benzene), or any mixture thereof. Exemplary dialkyl halides include, but are not limited to, 1,2-dichloroethane; 1,2-dibromoethane; 1,2-diiodoethane; 1,2-dichloropropane; 1,2-dibromopropane; 1,3-dichloropropane; 1,3-dibromopropane; 1,3-diiodopropane; 1,4-bis(chloromethyl)benzene; 1,4-bis(bromomethyl)benzene, or any mixture thereof.

Other useful symmetric crosslinking agents may include, but are not limited to, any one or more of the following:

식 중 R⁴는 (CH₂)_t이고, 및 여기에서 t는 1, 2, 또는 3임;

where R ⁴ is (CH ₂ ) _t , and where t is 1, 2, or 3;

식 중 x는 1 내지 약 100임;

where x is from 1 to about 100;

식 중 y는 1 내지 약 100임;

where y is from 1 to about 100;

식 중 x' + y'는 1 내지 약 100임; 및/또는

where x' + y' is 1 to about 100; and/or

식 중 z는 1 내지 약 100임; 이들의 임의의 조합을 포함함.

where z is from 1 to about 100; Including any combination of these.

Specific examples of symmetric crosslinking agents include N,N'-methylene-bis-acrylamide, N,N'-methylene-bis-methacrylamide, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) diglycyl. It may be or include dil ether, polyethylene glycol diacrylate, polyazetidinium compound, and any combination thereof.

According to a further aspect, the symmetrical crosslinker may be selected from a particular polymer or co-polymer having a type of functional moiety that is reactive with secondary amines, i.e., capable of functioning as a symmetrical crosslinker according to the present disclosure, or It can be included. In one aspect, these polymeric symmetric crosslinkers may be polymers or copolymers containing azetidinium functional groups. These polymer symmetric crosslinkers are, for example, azetidinium-functionalized monomers such as 1-isopropyl-3-(methacryloyloxy)-1-methylazetidinium chloride Q or 1,1-diallyl- It may be a copolymer of 3-hydroxyazetidinium chloride R (their structures are illustrated below) and acrylates, methacrylates, alkenes, dienes, etc.

Polymeric symmetric crosslinkers may also be, for example, copolymers of other azetidinium-functionalized monomers such as compounds S , T , or U as shown herein with acrylates, methacrylates, alkenes, dienes, etc. It may include or may include the above.

In this aspect, the symmetric crosslinker is selected from azetidinium-functionalized monomers selected from Q , R , S , T , U , and combinations thereof, and copolymers of acrylates, methacrylates, alkenes, or dienes. may be or may include the above, wherein the fraction of azetidinium-functionalized monomer relative to the acrylate, methacrylate, alkene, or diene monomer in the copolymer may be from about 0.1% to about 12%. . In a further aspect, the fraction of azetidinium-functionalized monomer to acrylate, methacrylate, alkene, or diene monomer in the copolymer is about 0.2% to about 10%, about 0.2% to about 10%, about 0.5%. %) to about 8%, from about 0.75% to about 6%, or from about 1% to about 5%. Examples of these types of symmetric crosslinker polymers and co-polymers can be found in the following references: Y.Bogaert, E.Goethals and E.Schacht, Makromol . Chem . , 182 , 2687-2693 (1981); M. Coskun, H. Erten, K. Demirelli and M. Ahmedzade, Polym . Degrad . Stab. , 69 , 245-249 (2000); and U.S. Patent No. 5,510,004.

According to one aspect, the symmetric crosslinking agent may be selected from or may comprise minimally azetidinium-functionalized polyamidoamines. That is, the polyamidoamine may have minimal azetidinium functionalization, which is a reactive moiety in this type of symmetric crosslinker. In this case, the crosslinking function is influenced by the azetidinium moiety, which can react with the secondary amines of the polyamidoamine prepolymer. Polyamidoamines suitable for preparing minimally azetidinium-functionalized polyamidoamines have the same general structures and formulas that can be used for preparing the resin itself, such as structures X , Y , and Z exemplified herein. Examples of minimally azetidinium-functionalized polyamidoamines suitable for use as symmetrical crosslinkers are illustrated by the following structures:

wherein p is at least 2, the q/p ratio is from about 10 to about 1000, and the structure has at least two azetidinium moieties that have the function of crosslinking and that characterize the structure such as X as a functionally symmetric crosslinker. Includes. As the q/p ratio indicates, there is a small fraction of azetidinium moieties when compared to acid and amine moieties. Moreover, the polyamidoamine One type of minimally azetidinium-functionalized polyamidoamine is provided, for example, in U.S. Pat. No. 6,277,242.

As illustrated by the molar ratio of symmetrical crosslinker to polyamine, for example in a PAE prepolymer, generally a relatively small fraction of the available secondary amine sites is crosslinked to form a branched or partially crosslinked polyamidoamine prepolymer. do. In addition to the molar ratios provided herein, for example, the symmetrical crosslinker to prepolymer molar ratio can be selected to provide 0.01% to 5% of the stoichiometric ratio of crosslinker to prepolymer. In a further aspect, the symmetric crosslinker to prepolymer molar ratio is 0.1% to 4%, 0.2% to 3.5%, 0.3% to 3%, 0.4% to 2.5%, 0.5% to 2%, or 0.6% to 1.5% can be provided. These values reflect the combined molar amounts when using crosslinkers with greater than 1 symmetry.

For example, polyamidoamine prepolymers derived from adipic acid and diethylenetriamine (DETA), and partially crosslinked polyamidoamines using prepolymer crosslinking with methylene-bis-acrylamide (MBA). The prepolymer can be exemplified by the following structure:

wherein the ^R

The above examples do not reflect the use of any monofunctional modifiers ( above ) in addition to symmetrical crosslinkers.

monofunctional modifier

The secondary amine groups of the polyamine may also be reacted with one or more monofunctional compounds to impart any desired chemical functionality to the prepolymer. Monofunctional compounds can be secondary or primary amines and non-cationic (to increase cationic charge density), hydrophilic or hydrophobic (to modulate interaction with non-ionic segments of cellulose fibers). It has a reactive group that can react with the reactive part. As desired, the polyamine can be reacted with a minor amount of a symmetric crosslinker and a minor amount of a monofunctional modifier that may include one secondary amine-reactive moiety before, during, or after the reaction step of the polyamine. Additionally, reactions with stoichiometric amounts of monofunctional modifiers can also be performed using any combination of reactions or additions before, during, or after reaction with a symmetrical crosslinker.

For example, in one aspect, the monofunctional modifier may be selected from neutral or cationic acrylate compounds, neutral or cationic acrylamide compounds, acrylonitrile compounds, mono-epoxide compounds, or any combination thereof. It may include or may include the above. According to a further aspect, the monofunctional modifier is an alkyl acrylate, acrylamide, alkyl acrylamide, dialkyl acrylamide, acrylonitrile, 2-alkyl oxirane, 2-(allyloxyalkyl)oxirane, hydroxyalkyl It may be selected from or include acrylates, ω-(acryloyloxy)-alkyltrimethylammonium compounds, ω-(acrylamido)-alkyltrimethylammonium compounds, and any combinations thereof. Examples of monofunctional modifiers are illustrated below.

For example, the monofunctional modifier can be or include at least one of the following: methyl acrylate; alkyl acrylates; acrylamide; N-methylacrylamide; N,N-dimethylacrylamide; acrylonitrile; 2-methyloxirane; 2-ethyloxirane; 2-propyloxirane; 2-(allyloxymethyl)oxirane; 2-hydroxyethyl acrylate; 2-(2-hydroxyethoxy)ethyl acrylate; 2-(acryloyloxy)-N,N,N-trimethylethanaminium; 3-(acryloyloxy)-N,N,N-trimethylpropane-1-aminium; 2-acrylamido-N,N,N-trimethylethanaminium; 3-acrylamido-N,N,N-trimethylpropane-1-aminium; and 1-isopropyl-3-(methacryloyloxy)-1-methylazetidinium chloride. Depending on the structure of the modifier, upon reaction of these compounds with secondary or primary amines, the portion that is non-reactive toward the amine may impart a cationic charge to help increase the cationic charge density, e.g. It has been shown that it is possible to change the hydrophilic or hydrophobic character, for example to adjust the interaction with the non-ionic segments of the cellulose fibers, and/or to influence other properties of the obtained intermediate crosslinked prepolymer. .

The monofunctional modifier may be present in amounts ranging from about 0.0001 mole, about 0.0005 mole, about 0.001 mole, about 0.005 mole, or about 0.01 mole to about 0.05 mole, about 0.07 mole, about 0.1 mole, about 0.15 mole per mole of secondary amine groups. , or in large quantities of about 0.2 mol may be reacted with the polyamine. For example, the monofunctional modifier may be reacted with the secondary amine groups of the polyamine in an amount of about 0.0001 mole to about 0.1 mole per mole of secondary amine groups.

halohydrin - functionalized polymer and intramolecular cyclization

Generally, by separating the reaction of the polyamine with the crosslinker into a separate step from the reaction of the intermediate crosslinked prepolymer with epichlorohydrin, the second reaction step requires less epichlorohydrin than conventional methods to achieve the desired endpoint. I need a giveaway. Additionally, the second reaction step can be effected under reaction conditions that favor optimized azetidinium group formation throughout further crosslinking. The asymmetric functional group of epichlorohydrin allows for the relatively facile reaction of the epoxy group with a secondary amine to form a pendant chlorohydrin moiety in the above functionalization, followed by the pendant chlorohydrin to form a cationic azetidinium functional group. It is useful in allowing intramolecular cyclization of This latter intramolecular cyclization can utilize heating of the halohydrin-functionalized polymer.

In one aspect, the second reaction step can be performed using any epihalohydrin, such as epichlorohydrin, epibromohydrin, and epiiodohydrin, or any combination thereof. For example, epichlorohydrin may be used. In this disclosure, where epichlorohydrin is listed, for example in a structure or reaction scheme, it is understood that any epihalohydrin can be used in the process.

By way of example, using the partially crosslinked polyamidoamine prepolymers exemplified above derived from adipic acid and DETA and crosslinking with MBA, the epichlorohydrin functionalized product has the following structure, aka "halohydrin-functionalized" It can be exemplified as “polymer”.

As before, the above examples do not reflect the use of any monofunctional modifiers in addition to symmetric crosslinkers. The reaction of epihalohydrins such as epichlorohydrin generally consumes a high percentage or the remaining secondary amine moieties in producing the halohydrin-functionalized polymer, in this case the chlorohydrin-functionalized polymer. It is aligned.

Formation of halohydrin-functionalized polymers can be accomplished using a range of epichlorohydrin molar ratios. For example, the reaction can be performed using excess epichlorohydrin. The stoichiometric reaction of secondary amine groups with epichlorohydrin requires a 1:1 molar ratio of secondary amine and epichlorohydrin. In one aspect, about 0.8 moles to about 3 moles of epichlorohydrin per mole of secondary amine can be used. Alternatively, about 0.9 moles to about 2.5 moles of epichlorohydrin per mole of secondary amine, about 1.0 moles to about 2.0 moles of epichlorohydrin per mole of secondary amine, about 1.1 moles to about 1.7 moles, about 1.2 moles. Moles to about 1.5 moles, about 1.25 moles to about 1.45 moles can be used. For example, the moles of epichlorohydrin per mole of secondary amine can be about 0.8, about 0.9, about 1.0, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, or about 1.6.

The amounts of symmetrical crosslinker and epihalohydrin may be sufficient to produce a strength resin that is substantially free of secondary amine groups. Although the results may be influenced by the use of the molar amounts and ratios disclosed herein, resin compositions made in accordance with the present disclosure cannot substantially contain secondary amine groups even when molar amounts and ratios other than those recited are used. By being substantially free of secondary amine groups, it is intended to mean that less than 10% of the original secondary amine remains in the starting PAE resin prior to crosslinking, functionalization, and cationization reactions. Alternatively, less than 5%, less than 2%, less than 1%, less than 0.5%, less than 0.2%, less than 0.1%, less than 0.01%, less than 0.005%, or less than 0.001% of the initial secondary amine in the starting PAE resin. may remain.

Halohydrin (typically chlorohydrin)-functionalized polymers can be converted to wet-strength resins by subjecting the polymer to cyclization conditions to form azetidinium ions. The functionalized polymer can be heated to form azetidinium ions. In contrast to conventional methods where heating induces both crosslinking and cyclization, the crosslinking portion of the process is completed once the cyclization is performed, thereby allowing for greater process control and more closely tailoring the desired properties of the resulting resin. Provides the ability to Also in contrast to conventional methods, the processes discussed and described herein reduce and/or minimize the formation of the epichlorohydrin byproduct 1,3-dichloro-2-propanol (1,3-DCP or “DCP”). and 3-chloropropane-1,2-diol (3-CPD or “CPD”) remaining in the resin can be reduced or minimized.

The concentration of epichlorohydrin 1,3-dichloro-2-propanol (1,3-DCP) remaining in the strength resin at 25% solids (DCP @ 25%) is less than about 15,000 ppm, less than about 14,000 ppm, less than about 13,000 ppm, less than about 12,000 ppm, less than about 11,500 ppm, less than about 11,000 ppm, less than about 10,500 ppm, less than about 10,000 ppm, less than about 8,000 ppm, less than about 6,000 ppm, or less than about 5,000 ppm.

The resin composition structure Z below is based on the chlorohydrin-functionalized polymer Y shown above , subject to conditions sufficient to intramolecularly cyclize the pendant chlorohydrin to impart azetidinium functionality. Illustrates the results of the cyclization (“cationization”) step to form

In the process of forming the resin composition, the resin composition is created by subjecting the halohydrin-functionalized polymer to cyclization conditions sufficient to convert the halohydrin groups to form azetidinium ions. At least a portion of the halohydrin group may be cyclized to form an azetidinium ion or moiety. In one example, at least 90% of the halohydrin groups can be cyclized to form azetidinium ions. Alternatively, at least 95%, at least 97%, at least 98%, at least 98.5%, at least 99%, at least 99.5%, at least 99.7%, at least 99.8%, or at least 99.9% of the halohydrin groups are azetidinium ions. Can be cyclized to form.

Additional steps in resin processing may be used, for example, to adjust the solids content of the composition beyond those detailed above. For example, the resin composition can be produced by converting a halohydrin-functionalized polymer to an azetidinium-functionalized polymer. After the above steps, the pH polymer composition can be adjusted so that the pH of the resin composition is about 2 to about 4.5. Alternatively, the pH of the resin may be from about 2.2 to about 4.2, from about 2.5 to about 4, or from about 2.7 to about 3.7. In another example, the pH of the polymer composition ranges from a low of about 2, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, or about 2.7 to about 3, when measured at a temperature of about 25°C. , about 3.2, about 3.4, about 3.6, about 2.8, about 4, about 4.2, or about 4.5. The pH adjustment step may also be followed by adjusting the solids content of the composition by about 10% to about 50% to form a strength resin. Alternatively, the solids content of the composition can be adjusted by about 15% to about 40% or about 20% to about 30% to form a strength resin. In another example, the strength resin may have a solids content of about 25%.

The resulting strength resin can have an improved charge density compared to that of conventional resins. For example, the strength resin can have a charge density of about 2 to about 4 mEq/g of solids. Alternatively, the strength resin may be from about 2.25 to about 3.5 mEq/g of solids, from about 2.3 to about 3.35 mEq/g of solids, from about 2.4 to about 3.2 mEq/g of solids, or from about 2.5 to about 3.0 mEq/g of solids. It can have a charge density of g.

The resulting strength resin may also have a ratio of azetidinium ions to amine moieties in the strength resin, abbreviated as “Azet”, of about 0.4 to about 2.3. The Azet ratio may also be from about 0.5 to about 1.9, from about 0.6 to about 1.6, or from about 0.7 to about 1.3. In another example, the ratio of azetidinium ions to secondary amine moieties in the resin may be from about 0.4 to about 1. Azet ratio can be measured by quantitative ¹³ C NMR by comparing the methylene carbon of azetidinium in the backbone to the methylene of the acid moiety.

In another example, the strength resin may have a Mw molecular weight of about 0.02 x 10 ⁶ to about 3.0 x 10 ⁶ . ^{Alternatively ,} the ^resin may have ^{a thickness of} about ^0.05 It may have a Mw molecular weight of 1.0 × 10 ⁶ . In another example, the resin can have a Mw molecular weight of about 0.05 x 10 ⁶ to about 1.7 x 10 ⁶ . Mw molecular weight can also be from about 0.6×10 ⁶ to about 1.6×10 ⁶ , from about 0.7×10 ⁶ to about 1.5×10 ⁶ , from about 0.8×10 ⁶ to about 1.3×10 ⁶ , or from about 0.9×10 ⁶ to about 1.1×10 6 It could be 10 ⁶ .

The strength resin may have an azetidinium equivalent, defined as the degree of polymerization times the Azet ratio, or (degree of polymerization) times (Azet), from about 1,600 to about 3,800. Alternatively, the azetidinium equivalent weight may be from about 1,800 to about 3,500, or from about 2,000 to about 2,900.

Strength resins may also possess various combinations of the disclosed properties. For example, the strength resin may be a combination of the disclosed properties such as charge density, Azet ratio, Mw molecular weight, azetidinium equivalent weight, 1,3-DCP content, halohydrin groups that cyclize to form azetidinium ions, etc. It may represent or have at least 2, at least 3, at least 4, or at least 5. For example, the strength resin may exhibit or possess at least 2, at least 3, at least 4, or all 5 of the following characteristic characteristics: (a) about 2.25 to about 3.5 mEq/g of solids; charge density of; (b) the ratio of azetidinium ion to amide in the strength resin is from about 0.7 to about 0.9; (c) Mw molecular weight of about 0.05×10 ⁶ to about 1.5×10 ⁶ ; (d) from about 1,800 to about 3,500 azetidinium equivalents; and (e) a 1,3-dichloro-2-propanol (1,3-DCP) content of less than about 10,000 ppm when the solids content is about 25%.

conventional wet strength Comparison with resin system

As described for conventional wet strength resin preparation, three main reactions occur in the conventional process: pendent chlorohydrin formation (ring-opening), cyclization to azetidinium ion groups (cationization), and cross-linking (intermolecular alkylation). ), when performed at room temperature, are approximately 140:4:1, respectively. Accordingly, pendant chlorohydrin groups form very rapidly from the ring-opening reaction of epichlorohydrin epoxide and secondary amines in prepolymers using an approximately 1:1 molar ratio of epichlorohydrin to secondary amine. The chlorohydrin group then cyclizes relatively slowly to form the cationic azetidinium group. Even more slowly, crosslinking occurs, for example, by: 1) tertiary amines of chlorohydrin pendant groups, reacting, for example, with azetidinium moieties; and/or 2) intermolecular alkylation of a pendant chlorohydrin moiety with a tertiary amine. Accordingly, at the crosslinking step in the reaction scheme, there are substantially no secondary amine groups remaining. Crosslinking results in an increase in molecular weight, manifested in an increase in resin viscosity.

To maintain practical utility for minimum reaction cycle times, the manufacturing process can be carried out under high temperature and high concentration conditions, where the reaction rates between intramolecular cyclization and crosslinking become competitive. Accordingly, one problem encountered in conventional manufacturing processes is making the crosslinking reaction rate fast enough that the desired viscosity endpoint (molecular weight) is achieved at the expense of azetidinium ion group formation. If the reaction continues beyond the desired viscosity endpoint to produce higher levels of azetidinium groups, the reaction mixture will likely gel and form a solid mass.

Because both high azetidinium group content and high molecular weight are useful for the maximum wet strength efficiency of the PAE resin, azetidinium group formation and crosslinking are preferably maximized without gelling the product or providing the product to gel during storage. These conditions, coupled with the requirement for high solids to minimize transportation costs, are limiting aspects of the formation of higher efficiency wet strength resin products.

In contrast, the strength resins and processes discussed and described herein address this issue, at least in part, by providing higher azetidinium ion content, an additional degree of reactive functionalization, increased molecular weight, and very good storage stability. Strength resins provide improved wet tensile development over current technology when used in paper, board, tissue and towel applications.

A comparison of wet strength resin properties with standard commercially available wet strength resins is provided in the examples and tables. The wet strength resin properties of resins prepared according to the present disclosure were compared and tested with standard commercially available wet strength resin products, including the AMRES® series of resins (Georgia-Pacific) and KYMENE® (Ashland) resins. . Both the performance of the resins to impart wet strength and the properties of the resins themselves are compared in the table below. The data illustrate significant improvements in resin properties (Table 1), such as increased charge density, higher ratio of azetidinium ions to amide moieties, higher molecular weight, greater azetidinium equivalent weight, and lower by-product contaminants. This was observed for the disclosed resin when compared to conventional resins.

According to another aspect, a strength resin is provided for improving the wet strength of paper. A method of making a resin or resin composition may include reacting a polyamine with a symmetric crosslinking agent to produce a partially crosslinked polyamine. Epihalohydrins can be added to partially crosslinked polyamines to produce halohydrin-functionalized polymers. Halohydrin-functionalized polymers can be cyclized to form resins with azetidinium moieties.

When the polyamine (polyamine prepolymer) is selected from polyamidoamine prepolymers, a further aspect of the present disclosure provides a resin for improving the strength of paper, for example wet strength, wherein the resin is functionally derived from a symmetrical crosslinker. It contains a polyamidoamine polymer that is crosslinked with a bridging moiety and has azetidinium ions. A method of making a resin or resin composition involves adding secondary amine-reactive moieties to provide a partially crosslinked polyamidoamine prepolymer that retains a majority of the secondary amine groups present in the polyamidoamine prepolymer, e.g. It may involve the reaction of a polyamidoamine (PAA) prepolymer with secondary amine groups with an insufficient amount of a symmetric crosslinking agent. If desired, the polyamidoamine prepolymer can be reacted with a minor amount of a monofunctional modifier, which may contain one secondary amine-reactive moiety, before, during, or after reaction with the symmetric crosslinker. Partially crosslinked polyamidoamine prepolymers can be reacted with epihalohydrins to provide halohydrin-functionalized polymers. The resin composition can be formed by subjecting the halohydrin-functionalized polymer to conditions sufficient to cyclize at least a portion of the halohydrin groups to form azetidinium ions.

Optional papers reinforced with strength resins are also an aspect of the present disclosure and provided herein. Moreover, the process of treating paper to impart wet strength can include treating the fibers used to make the paper with dry resin solids, wherein the resin is any resin within the context of this disclosure. For example, the process may include treating the fibers used to make paper with about 0.05% to about 2% dry resin solids by weight based on the dry weight of the fibers of the cationic thermoset resin or resin composition, wherein A resin or resin composition is prepared according to the present disclosure. The process of treating paper to impart wet strength may include treating the fibers used to make the paper with about 0.01% to about 2% dry resin solids by weight, based on the dry weight of the fibers of the cationic thermoset resin composition. . Alternatively, the process may use from about 0.05% to about 1.8%, from about 0.075% to about 1.6%, or from about 0.1% to about 1.5% dry resin solids by weight, based on the dry weight of the fibers. . The fibers may be pulp fibers.

Although each resin composition property disclosed herein is described in detail independently of other properties, it is intended that any resin composition property may occur in the disclosed resins with any other resin property or properties. For example, and not by way of limitation, the disclosure of properties herein includes compositions that may have at least 1, at least 2, at least 3, at least 4, or at least 5 of the following properties: a) a charge density of about 1.0 to about 4.0 mEq/g of solids; b) the ratio of azetidinium ions to amide moieties in the resin is from about 0.5 to about 0.9; c) a molecular weight of about 0.05×10 ⁶ to about 3.0×10 ⁶ ; d) from about 1,800 to about 3,500 azetidinium equivalents; and e) a 1,3-dichloro-2-propanol (1,3-DCP) content of less than about 10,000 ppm when the solids content is about 25%.

To further define the terms used herein, unless otherwise indicated, the definitions do not limit or preclude any claim from being applied by, for example, failure to adhere to conventional rules of chemical valency. The following definitions, as applicable to this disclosure, are provided. If a term is used in this disclosure but not specifically limited herein, so long as the definition does not conflict with any other disclosure or definition applied herein, or does not limit or preclude any claim to which the definition applies, Definitions may be applied from the IUPAC overview in Chemical Terminology, ^2nd Ed (1997). To the extent that any definition or usage provided by any document incorporated by reference herein conflicts with a definition or usage provided herein, the definitions or usage provided herein shall control.

While compositions and methods are described in terms of “comprising” various ingredients or steps, compositions and methods may also “consist essentially of” or “consist of” various ingredients or steps.

Unless otherwise specified, any carbon-containing group with an unspecified number of carbon atoms may, according to appropriate chemical practice, be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 carbon atoms, or any range or combination between these values You can have it. For example, unless otherwise specified, any carbon-containing group may have 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms. It may have carbon atoms, etc. Moreover, other identifiers or quantification terms can be used to indicate the presence or absence of specific substituents, specific regiochemistry and/or stereochemistry, or absence of branched base structures or backbones.

The term "substituted" when used to describe a group, for example, when referring to a substituted analog of a particular group, is intended to describe any non-hydrogen moiety that formally replaces a hydrogen in that group, and is not limited to It is a malicious intention. However, Applicant reserves the right to limit the scope of any claim, e.g., to explain any prior disclosure that Applicant may not be aware of. A group or groups may also be referred to herein as "unsubstituted" or by equivalent terms such as "unsubstituted", which refers to the original group in which the non-hydrogen moiety does not replace a hydrogen in the group. “Substituted” is intended to be non-limiting and includes inorganic or organic substituents as specified and understood by those skilled in the art.

The term “alkyl group” as used herein is a general term referring to a group formed from an alkane by the removal of one or more hydrogen atoms (as required for the particular group). Accordingly, “alkyl group” includes the definition given by IUPAC of a monovalent group formed by the formal removal of a hydrogen atom from an alkane, but also as the context requires, so long as the ordinary rules of chemical valency apply, for example, or Where permitted, it includes "alkanediyl groups" formed by the formal removal of two hydrogen atoms from an alkane (two hydrogen atoms from one carbon atom or one hydrogen atom from two different carbon atoms). Alkyl groups may be substituted or unsubstituted groups, may be acyclic or cyclic groups, and/or may be linear or branched, unless otherwise specified.

The term “cycloalkyl group” as used herein is a general term referring to a group formed from a cycloalkane by the removal of one or more hydrogen atoms (as required for the particular group). Accordingly, “cycloalkyl group” includes the definition given by IUPAC of a monovalent group formed by the formal removal of a hydrogen atom from a cycloalkane, but also as the context requires, so long as the ordinary rules of chemical valency apply, e.g. A "cycloalkanediyl group" formed by the formal removal of two hydrogen atoms from an alkane (either two hydrogen atoms from one carbon atom or one hydrogen atom from two different carbon atoms) Includes. Alkyl groups may be substituted or unsubstituted groups, may be acyclic or cyclic groups, and/or may be linear or branched, unless otherwise specified. When two hydrogens are formally removed from a cycloalkane to form a "cycloalkyl" group, the two hydrogen atoms are from the same ring carbon, from two different ring carbons, or from one ring carbon and one non-ring carbon. It can be formally removed from a carbon atom.

“Aryl group” refers to an aromatic compound, specifically a group formed by the removal of one or more hydrogen atoms (as required for the particular group and at least one of these is an aromatic ring carbon atom) from an arene. Thus, an “aryl group” includes a monovalent group formed by formal removal of a hydrogen atom from an arene, but also, for example, by formal removal of two hydrogen atoms (at least one of them from an aromatic hydrocarbon ring carbon) from the arene. Includes an “arendiyl group” occurring in. Accordingly, aromatic compounds are compounds that contain periodically fused hydrocarbons that follow the Hueckel (4n+2) rule and that contain (4n+2) pi-electrons, where n is an integer from 1 to about 5. Accordingly, aromatic compounds and therefore “aryl groups” may be monocyclic or polycyclic, unless otherwise specified.

“Heteroaryl group” refers to a group formed by the removal of one or more hydrogen atoms (optionally for the particular group and at least one of these is an aromatic ring carbon or heteroatom) from a heteroaromatic compound. Accordingly, one or more hydrogen atoms may be removed from the ring carbon atom and/or from the heteroaromatic ring or ring system heteroatom. Accordingly, a “heteroaryl” group or moiety is a “heteroarene” that arises by formal removal of two hydrogen atoms from a heteroarene compound, wherein at least one of the heteroarene compounds may be a heteroarene ring or ring carbon atom. Includes “Diil Ki”. Thus, in a “heteroarendiyl group” at least one hydrogen is removed from a heteroarene ring or ring system carbon atom and the other hydrogen atom is removed from, for example, a heteroarene ring or ring system carbon atom, or a non-heteroarene ring. or from any other carbon atom, including ring-based atoms.

An “amide” group or moiety refers to a group formed from an amide compound, including organic amide compounds, by the removal of one or more hydrogen atoms (as required for the particular group). Accordingly, one or more hydrogen atoms may be from a carboxyl group carbon, from an amide nitrogen, from any organic moiety bonded to a carboxyl group carbon or an amide nitrogen, or from an organic moiety bonded to a carboxyl group carbon and an amide nitrogen. It can be removed from the tee. Often, for example, when an amide group links an amine in a polyamine, the "amide" group or moiety is formed from the formal removal of a hydrogen atom from each of the two organic groups, one bonded to the carboxyl group and the other to the amide nitrogen. Occurs. The term may be used for any amide moiety, whether or not an amide or an aliphatic or aromatic organic group.

The use of various substituted analogs or formal derivatives of any of these groups may also be disclosed, in which case the analogs or formal derivatives are, but are not limited to, the number of substituents or specific regiochemistry, unless otherwise indicated. For example, the term “hydroxyalkyl” refers to a group formed by formal removal of one or more hydrogen atoms (as required for the particular group) from the alkyl portion of a hydroxy-substituted alkane. Hydroxy-substituted alkanes may contain one or more hydroxy substituents. Thus, a "hydroxyalkyl" group may, for example, have two hydrogen atoms (two hydrogen atoms from one carbon atom) from a "hydroxyalkyl" alkane if the context requires or allows, as long as the ordinary rules of chemical valency apply. and hydroxy-substituted "alkanediyl" groups, which are formed by formal removal of a hydrogen atom (or one hydrogen atom from two different carbon atoms). As indicated with respect to alkyl groups, alkyl groups may be substituted or unsubstituted groups, may be acyclic or cyclic groups, and/or may be linear or branched, unless otherwise specified.

The synthesis of a standard PAE wet strength resin using epichlorohydrin, adipic acid and DETA is shown in Scheme 1. Resins according to one or more embodiments discussed and described herein that utilize a symmetrical crosslinker, methylene bis-acrylamide (MBA), are shown in Scheme 2.

Prepolymer, adipic acid, glutaric acid, step #1, intermediate crosslinked prepolymer, MBA = methylene-bis-acrylamide, step #2, epichlorohydrin, 1.35 mol/secondary amine, intramolecular cyclization azeti dinium ion, suspended chlorohydrin

Scheme 2

wet strength Resin Azetidinium rain ( Azet B) of ¹³ C NMR determination

The azetidinium ratio, or “Azet” ratio, is the ratio of polymer segments containing azetidinium ions to the total number of polymer segments. A single polymer segment is defined as a condensation moiety derived from one diacid molecule (e.g., adipic acid) and one triamine molecule (e.g., diethylenetriamine or DETA), illustrated below.

Azetidinium ion ratios are determined by quantitative (back-gated heteronuclear decoupled) ¹³ C NMR spectroscopy, using a relaxation time of 22.5 seconds, a spectral width of 15,000 Hz (240 ppm), and 320 to 1024 scans. . The measurements were carried out by integration of the methylene peak at the azetidinium ion and the internal carbon of the adipic acid portion of the polymer. The adipic acid moiety is assigned to be the total number of polymer segments. Therefore, when the polymer is prepared using adipic acid, the azetidinium ratio is determined according to the formula:

Azetidinium ion ratio (Azet ratio) = A(azet) / A(adip), where:

A(azet) is the integrated area of methylene from azetidinium ion; A(adip) is the integrated area of methylene from adipic acid moieties (total polymer segments). The method may be adapted to any resin disclosed herein. Therefore, for the adipic acid-based polymer, the azetidinium ion peak at 74 ppm and the backbone methylene peak at 25 ppm were both integrated and the methylene peak at 25 ppm was normalized to 1. For the glutaric acid based polymer, the azetidinium ion peak at 74 ppm and the backbone methylene peak at 22 ppm were both integrated and the methylene peak at 22 ppm was normalized to 1.

wet strength Charge density of resin

The charge densities of cationic polyamidoamine-epichlorohydrin (PAE) wet strength resins with typical non-volatile contents of about 10% to about 50% were measured using a Muetek (Muetek) PCD-03 particle charge detector and titrator as follows: It was measured using The charge density was determined by streaming current potential measurements of dilute solutions of polycationic resins by titration with polyanionic solutions of polyvinyl sulfate (PVSK). The non-volatile content of the PAE resin is predetermined and the charge density is reported in milliequivalents (+) per gram of solid (meq+/g).

Under the action of van der Waals forces, the polycationic resin is preferentially adsorbed on the surface of the test cell and its oscillatory displacement piston, and as the diffusion cloud of counter ions is sheared directly into the cationic colloid by the liquid flow in the test cell, So-called streaming currents are induced. Electrodes on the test cell wall measure the streaming current. The PAE resin is titrated with PVSK until the PAE resin reaches a point of zero charge, and the initial resin charge is calculated from the titrant consumption. The streaming current is used to calculate the milliequivalents/gram solids balance (meq+/gram) of cationic charge as follows:

Charge Density = (PVSK(mL) * PVSK(N)) / (Gram Active Resin) = meq+ / Gram

manufacture of sheets

The pulp stock used in the handsheet operation was unique for each study, as indicated in Tables 2, 3, and 4. Resin was added at the lb/ton of pulp solids indicated in the table (% thick stock) for the diluted stock consistency indicated in each table, allowing for a 2-minute mixing time. The treated stock was immediately poured into the headbox of a Noble & Wood handsheet machine containing pH pre-adjusted water (pH 7.0). The target sheet standard weight was 30 lb/3000 ft ² . Each wet sheet was given two passes through a full load wet press and then placed in a 105° C. drum dryer without blotting paper for 1 minute. The entire set of handsheets was further cured for 10 minutes at 105° C. in a forced air oven. Handsheet samples were kept at constant humidity (50%) and constant temperature (73°F) for 24 hours prior to testing.

Tensile measurements

Dry tensile and wet tensile (test samples immersed in distilled water at 23.0±0.2°C) were tested to determine improved paper dry and wet tensile strength performance. Dry and wet tensiles are reported for wet and dry break lengths (wet BL and dry BL) in kM/m. The dry tensile measurement method refers to TAPPI test method T494 om-01 (effective date September 5, 2001). The wet tensile measurement method refers to TAPPI test method T456 om-03 (effective date May 13, 2003).

% Wet/Dry Tensile ( % W/D tensile)

% Wet/Dry Tensile is measured as the percentage of wet to dry tensile, i.e., % W/D BL (Break Length) is (Wet Tensile Break Length)/(Dry Tensile Break Length) x 100.

Wetting and Drying tear

The dry tear measurement method refers to TAPPI Test Method T 414-om-04 (effective May 3, 2004). Wet tear measurements were determined by TAPPI Test Method T 414-om-04 (effective May 3, 2004).

Example

The following examples are provided to illustrate various implementations of the disclosure and claims. Unless otherwise specified, reagents were obtained from commercial sources. The following analytical methods were used to characterize the resin.

Example One. polyamidoamine prepolymer Manufacturing of I

The five-neck top glass reactor was equipped with a stainless steel stirring shaft, reflux condenser, temperature probe, and hot oil bath. 500.5 grams of DETA (diethylenetriamine) was added to the reactor. The stirrer was started and 730 grams of adipic acid was slowly added to the reactor over 45 minutes with agitation. The reaction temperature increased from 25°C to 145°C during adipic acid addition. After the adipic acid addition was completed, the reactor was immersed in a hot oil bath heated to 160°C. At 150°C the reaction mixture began to reflux. The reflux condenser was reconstituted for distillation and the distillate was collected in a separate vessel. The reaction mixture was sampled at 30 minute intervals. Each sample was diluted to 45% solids with water and viscosity was measured with a Brookfield viscometer. When the sample reached 290 cP the distillation condenser was reconfigured for reflux. Water was added slowly to the reaction mixture through a reflux condenser to dilute and cool the reaction. Water was added to give a final solids of 45%. The viscosity was 290 cP.

Example 2. polyamidoamine prepolymer Manufacturing of II

The five-neck top glass reactor was equipped with a stainless steel stirring shaft, reflux condenser, temperature probe, and hot oil bath. 1574.5 grams DBE-5 (glutaric acid dimethyl ester, or dibasic ester) was added to the reactor. The stirrer was started and 1038.9 grams of DETA were added to the reactor with agitation. The reactor was immersed in a hot oil bath heated to 100°C. At 90°C the reaction mixture began to reflux. The reflux condenser was reconstituted for distillation and the distillate was collected in a separate vessel. The reaction mixture was sampled at 30 minute intervals. Each sample was diluted to 45% solids with water and viscosity was measured with a Brookfield viscometer. When the sample reached 220 cP the distillation condenser was reconfigured for reflux. Water was added slowly to the reaction mixture through a reflux condenser to dilute and cool the reaction. Water was added to give a final solids of 45%. The viscosity was 220 cP.

Example 3. wet strength Preparation of Resin

Step 1 . The five-neck top glass reactor was equipped with a glass stirring shaft and Teflon paddle, equal pressure input funnel, temperature and pH probes, stainless steel cooling coil, sample valve, and heating mantle. 445.64 grams of polyamidoamine prepolymer II from Example 2 was added to the reactor. Water, 5.25 grams, was added and the stirrer was started. The reaction mixture was heated to 35° C. and 2.028 grams of N,N -methylene-bis-acrylamide (Pfaltz & Bauer, Inc.) was added. The reaction mixture was heated to 60° C. and maintained at that temperature for 4 hours. The viscosity of the reaction mixture progressed to 384 cP (Brookfield-SSA). The intermediate (partially cross-linked) prepolymer mixture was used in situ in Step 2 below.

Step 2 . The reaction temperature of the intermediate prepolymer mixture from Step 1 was adjusted to 25° C. and 88.46 grams of water were added. The reaction temperature was then adjusted to 21°C and 121.21 grams of epichlorohydrin were added over 75 minutes. The reaction mixture was allowed to warm to 25° C. over 45 minutes and 446.27 grams of water were added. The reaction mixture was heated to 45°C and after 2 hours to 55°C. After about 4 hours, a mixture of formic acid and sulfuric acid was added to adjust the pH to 2.87. (Generally, the pH can be adjusted using any organic acid, inorganic acid, or combination thereof, such as acetic acid, formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, or any combination thereof.) The reaction mixture is It was then cooled to 25°C and water was added to adjust the solids to 25.0%. The viscosity of the obtained wet strength resin was 187 cP.

Example 4. wet strength Preparation of Resin

Step 1 . The five-neck top glass reactor was equipped with a glass stirring shaft and Teflon paddle, equal pressure input funnel, temperature and pH probes, stainless steel cooling coil, sample valve, and heating mantle. 1000.00 grams of polyamidoamine prepolymer I from Example 1 was added to the reactor. The stirrer was started and the prepolymer was heated to 40°C. N,N -methylene-bis-acrylamide, 15.16 grams (Pfaltz & Bauer, Inc) was added slowly while the reaction mixture was heated to 60°C. The reaction mixture was then held at 60°C for approximately 2 hours and the viscosity developed to 4,630 cP (Brookfield-SSA), at which point the viscosity progression ceased. The reaction was cooled to 25°C. The intermediate (partially cross-linked) prepolymer was isolated and stored.

Step 2 . To a reactor configured as described in Step 1 was added 366.04 grams of intermediate (partially crosslinked) prepolymer from Step 1 above. The reaction temperature was adjusted to 25°C and 120.13 grams of water was added. The viscosity of the reaction mixture was 837 cP. To the intermediate partially crosslinked prepolymer was added 77.89 grams of epichlorohydrin over 90 minutes at 25°C. 428.19 grams of water was added to the reaction mixture. The reaction was maintained at 25°C for 18 hours during which time samples were periodically sampled for ¹³ C NMR analysis. During this time the viscosity of the reaction increased from 18 cP to 319 cP (Brookfield-SSA). The reaction was treated with concentrated sulfuric acid to adjust the pH to 2.94. The reaction mixture was adjusted to 25.0% solids and the viscosity was 335 cP.

Example 5. wet strength Preparation of Resin

Step 1 . The five-neck top glass reactor was equipped with a glass stirring shaft and Teflon paddle, equal pressure input funnel, temperature and pH probes, stainless steel cooling coil, sample valve, and heating mantle. 449.10 grams of polyamidoamine prepolymer II from Example 2 was added to the reactor. The stirrer was started, the reaction mixture was heated to 30° C., and 6.92 grams of poly(propylene glycol) diglycidyl ether (Polystar) was added over 1 hour. The reaction mixture was held at 30°C for 1 hour and then heated to 60°C, at which point the viscosity was 416 cP. The reaction mixture was heated at 60° C. for about 4 hours and the viscosity developed to 542 cP (Brookfield-SSA). The intermediate crosslinked prepolymer was used in situ in the subsequent step 2 .

Step 2 . The reaction temperature of the intermediate prepolymer mixture from Step 1 was adjusted to 25° C. and 80.10 grams of water was added. 118.79 grams of epichlorohydrin were added to the reactor over 75 minutes. The reaction was allowed to warm to 30° C. over 45 minutes and 431.35 grams of water were added. The reaction was warmed to 45°C over 45 minutes and to 50°C after 2 hours. After about 3.5 hours the viscosity of the reaction was about 320 cP (Gardner-Holdt bubble tube) and then a mixture of formic acid and sulfuric acid was added to adjust the pH to 3.00. The reaction mixture was cooled to 25° C. and water was added to adjust the solids to 25.0%. The viscosity of the obtained wet strength resin was 219 cP.

Example 6. of handsheet manufacturing

A comparison of wet strength resin performance with standard commercially available wet strength resins is provided in the Examples and Data Tables. Each data table indicates the stock used in the comparison and the stock freeness (CSF) is reported. Resin was added at the rates shown (lb resin/ton of pulp solids) to thick stock allowing for a 2-minute mixing time. The treated stock was immediately poured into the headbox of a Noble & Wood handsheet machine containing pH pre-adjusted water.

Target sheet reference weight is expressed in lb/ft ² in each set of data. Each wet sheet was given two passes through a full load wet press and then placed in a 105° C. drum dryer without blotting paper for 1 minute. The entire set of handsheets was further cured for 10 minutes at 105° C. in a forced air oven. Handsheet samples were kept at constant humidity (50%) and constant temperature (73°F.) for 24 hours prior to testing. Any additional conditions are reported in the table. Handsheet samples were kept at constant humidity (50%) and constant temperature (73°F.) for 24 hours prior to testing.

Composition resins were added at the rate (lb/ton) of pulp solids as indicated in the respective data tables to the thick stock (reference table) allowing for a 2-minute mixing time. The treated stock was immediately poured into the headbox of a Noble & Wood handsheet machine containing pH pre-adjusted water (pH 7.0). The weight based on the target sheet is indicated in each table. Each wet sheet was given two passes through a full load wet press and then placed in a 105° C. drum dryer without blotting paper for 1 minute. The entire set of handsheets was further cured for 3 minutes at 105° C. in a forced air oven. Handsheet samples were kept at constant humidity (50%) and constant temperature (73°F.) for 24 hours prior to testing.

Example 7. Evaluation of composition properties and performance

A comparison of wet strength resin properties with standard commercially available wet strength resins is provided in the table below. The wet strength resin properties of the resins prepared according to the present disclosure were compared and tested with standard commercially available wet strength resin products, including the Amres® series (Georgia-Pacific) and Kymene® (Ashland) resins. . Both the properties of the resin itself and the performance of the resin for imparting wet strength are compared in the table below.

Table 1 illustrates that wet strength resins prepared according to the present disclosure show significant improvements in properties when compared to commercially available resins. For example, at comparable solids content, the Example 3 resin has significantly higher charge density, ratio of azetidinium ions to amide moieties, molecular weight, azetidinium equivalent weight, and other properties when compared to conventional resins. . Moreover, the undesirable 1,3-dichloro2-propanol (1,3-DCP) content in the obtained resin is substantially reduced.

Table 2 illustrates the improvement in wet break length of premium grade heavy weight towels when treated with resins according to the present disclosure. A comparison of data measured at different application rates and the same properties obtained using conventional resins is presented. Substantial improvements in properties are observed using resins prepared according to this disclosure.

Table 3 likewise illustrates the improvement in wet cut length of recycled weight towels when treated with resins according to the present disclosure at different application rates (5, 10, and 15 lb composition resin/ton of pulp solids). A comparison of the same properties obtained using conventional resins is provided. In all cases, substantial improvements in performance are demonstrated using the disclosed wet strength resins.

Similarly, Table 4 shows the wet tensile of single section lengths of unbleached SW kraft at different application rates (4, 6, and 8 lb composition resin/ton of pulp solids) and % wet/ton when compared to more conventional resin materials. Illustrates improvement in dry tensile strength. In each case, improvements in performance were observed using the disclosed wet strength resins. Wet tear was also reported and measured using the indicated resins, and again, improvement in performance using the disclosed wet strength resins at all application rates is demonstrated.

Implementations of the present disclosure relate to any one or more of the following paragraphs:

1. A method for producing a resin, comprising the following steps: a) reacting a polyamine with a symmetrical cross-linking agent to produce a partially cross-linked polyamine; b) adding epihalohydrin to the partially crosslinked polyamine to produce a halohydrin-functionalized polymer; and c) cyclizing the halohydrin-functionalized polymer to form a resin with azetidinium moieties.

2. The method of paragraph 1, wherein the polyamine has the structure:

wherein R is alkyl, hydroxyalkyl, amine, amide, aryl, heteroaryl, or cycloalkyl and w is from 1 to about 10,000.

3. The method of paragraph 1, wherein the polyamine has a molecular weight of about 2,000 to about 1,000,000.

4. The method of paragraph 3, wherein the polyamine has a molecular weight of about 10,000 to about 200,000.

5. The method of paragraph 1, wherein the symmetric crosslinking agent is selected from diacrylates, bis(acrylamides), diepoxides and polyazetidinium compounds.

6. The method of paragraph 1, wherein the symmetric crosslinking agent is selected from:

Insert chemical formula

식 중 R⁴는 (CH₂)_t이고, 및 t는 1, 2, 또는 3임;

where R ⁴ is (CH ₂ ) _t , and t is 1, 2, or 3;

식 중 x는 1 내지 약 100임;

where x is from 1 to about 100;

식 중 y는 1 내지 약 100임;

where y is from 1 to about 100;

식 중 x' + y'는 1 내지 약 100임;

where x' + y' is 1 to about 100;

식 중 z는 1 내지 약 100임;

where z is from 1 to about 100;

식 중 q/p 비는 약 10 내지 약 1000임;

wherein the q/p ratio is from about 10 to about 1000;

로부터 선택된 아제티디늄-작용화된 모노머와의 코폴리머, 및 이들의 조합, 여기에서 코폴리머에서 아제티디늄-작용화된 모노머 대 아크릴레이트 모노머, 메타크릴레이트 모노머, 알켄 모노머, 또는 디엔 모노머의 분획이 약 0.1% 내지 약 12%임; 및 이들의 임의의 조합.of acrylate monomers, methacrylate monomers, alkene monomers, or diene monomers,

copolymers with azetidinium-functionalized monomers selected from, and combinations thereof, wherein in the copolymer the azetidinium-functionalized monomer is selected from The fraction is from about 0.1% to about 12%; and any combination thereof.

7. The method of paragraph 1, wherein the symmetric crosslinking agent is N,N'-methylene-bis-acrylamide, N,N'-methylene-bis-methacrylamide, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) ) selected from diglycidyl ether, polyethylene glycol diacrylate, polyazetidinium compounds, and any combinations thereof.

8. The method of paragraph 1, wherein the epihalohydrin is selected from epichlorohydrin, epibromohydrin, and epiiodohydrin.

9. The method of paragraph 8, wherein the epihalohydrin is epichlorohydrin.

10. The method of paragraph 1, further comprising reacting the polyamine with a monofunctional modifier prior to, during, or after treatment with the symmetric crosslinking agent.

11. The method of paragraph 10, wherein the monofunctional modifier is selected from neutral or cationic acrylate compounds, neutral or cationic acrylamide compounds, acrylonitrile compounds, mono-epoxide compounds, or combinations thereof.

12. The method of paragraph 10, wherein the monofunctional modifier is alkyl acrylate, acrylamide, alkyl acrylamide, dialkyl acrylamide, acrylonitrile, 2-alkyl oxirane, 2-(allyloxyalkyl)oxirane, hydroxyl A method selected from alkyl acrylates, ω-(acryloyloxy)-alkyltrimethylammonium compounds, ω-(acrylamido)-alkyltrimethylammonium compounds, and any combinations thereof.

13. The method of paragraph 10, wherein the monofunctional modifier comprises at least one of the following: methyl acrylate, alkyl acrylate, acrylamide, N-methylacrylamide, N,N-dimethylacrylamide, acrylonitrile. , 2-methyloxirane, 2-ethyloxirane, 2-propyloxirane, 2-(allyloxymethyl)oxirane, 2-hydroxyethyl acrylate, 2-(2-hydroxyethoxy)ethyl acrylate , 2-(acryloyloxy)-N,N,N-trimethylethanaminium, 3-(acryloyloxy)-N,N,N-trimethylpropane-1-aminium, 2-acrylamido- N,N,N-trimethylethanaminium, 3-acrylamido-N,N,N-trimethylpropane-1-aminium, and 1-isopropyl-3-(methacryloyloxy)-1-methyl Azetidinium chloride.

14. The method of paragraph 1, wherein the ratio of azetidinium ions to secondary amine moieties in the resin is from about 0.4 to about 1.0.

15. The method of paragraph 1, wherein the concentration of 1,3-dichloro-2-propanol (1,3-DCP) is less than about 15,000 ppm.

16. The method of paragraph 1, wherein the pH of the resin is adjusted using an acid.

17. The method of paragraph 16, wherein the acid is acetic acid, formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, an organic acid or an inorganic acid, or a combination thereof.

18. The method of paragraph 16, wherein the pH of the resin is adjusted to about pH 2.0 to about pH 4.5.

19. The method of paragraph 1, wherein the solids content of the resin is adjusted from about 10% to about 50%.

20. The method of paragraph 1, wherein the resin has a charge density of from about 1.0 to about 4.0 mEq/g of solids.

21. The method of paragraph 1, wherein the resin has a ratio of azetidinium ions to amide moieties from about 0.5 to about 0.9.

22. The method of paragraph 1, wherein the resin has a molecular weight of from about 0.02 x 10 ⁶ to about 3.0 x 10 ⁶ .

23. The method of paragraph 1, wherein the resin has an azetidinium equivalent weight of about 1,800 to about 3,500.

24. The method of paragraph 1, wherein the resin has a 1,3-dichloro-2-propanol (1,3-DCP) content of less than about 10,000 ppm.

25. A composition comprising a resin, wherein the resin is prepared by a method comprising the following steps: a) reacting the polyamine with a symmetric crosslinking agent to produce a partially crosslinked polyamine; b) adding epihalohydrin to the partially crosslinked polyamine to produce a halohydrin-functionalized polymer; and c) cyclizing the halohydrin-functionalized polymer to form a resin with azetidinium moieties.

26. The composition of paragraph 25, wherein the polyamine has the structure:

wherein R is alkyl, hydroxyalkyl, amine, amide, aryl, heteroaryl, or cycloalkyl and w is from 1 to about 10,000.

27. The composition of paragraph 25, wherein the polyamine has a molecular weight of about 2,000 to about 1,000,000.

28. The composition of paragraph 27, wherein the polyamine has a molecular weight of about 10,000 to about 200,000.

29. The composition of paragraph 25, wherein the symmetric crosslinking agent is selected from diacrylates, bis(acrylamides), diepoxides and polyazetidinium compounds.

30. The composition of paragraph 25, wherein the symmetric crosslinking agent is selected from:

Insert chemical formula

식 중 R⁴는 (CH₂)_t이고, 및 t는 1, 2, 또는 3임;

where R ⁴ is (CH ₂ ) _t , and t is 1, 2, or 3;

식 중 x는 1 내지 약 100임;

where x is from 1 to about 100;

식 중 y는 1 내지 약 100임;

where y is from 1 to about 100;

식 중 x' + y'는 1 내지 약 100임;

where x' + y' is 1 to about 100;

식 중 z는 1 내지 약 100임;

where z is from 1 to about 100;

식 중 q/p 비는 약 10 내지 약 1000임;

wherein the q/p ratio is from about 10 to about 1000;

로부터 선택된 아제티디늄-작용화된 모노머와의 코폴리머, 및 이들의 조합, 여기에서 코폴리머에서 아제티디늄-작용화된 모노머 대 아크릴레이트 모노머, 메타크릴레이트 모노머, 알켄 모노머, 또는 디엔 모노머의 분획이 약 0.1% 내지 약 12%임; 및 이들의 임의의 조합.of acrylate monomers, methacrylate monomers, alkene monomers, or diene monomers,

copolymers with azetidinium-functionalized monomers selected from, and combinations thereof, wherein in the copolymer the azetidinium-functionalized monomer is selected from The fraction is from about 0.1% to about 12%; and any combination thereof.

31. The method of paragraph 25, wherein the symmetric crosslinking agent is N,N'-methylene-bis-acrylamide, N,N'-methylene-bis-methacrylamide, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) ) a composition selected from diglycidyl ether, polyethylene glycol diacrylate, polyazetidinium compounds, and any combinations thereof.

32. The composition of paragraph 25, wherein the epihalohydrin is selected from epichlorohydrin, epibromohydrin, and epiiodohydrin.

33. The composition of paragraph 32, wherein the epihalohydrin is epichlorohydrin.

34. The composition of paragraph 25, wherein the method further comprises the steps of: reacting the polyamine with the monofunctional modifier before, during, or after treatment with the symmetrical crosslinker.

35. The composition of paragraph 34, wherein the monofunctional modifier is selected from a neutral or cationic acrylate compound, a neutral or cationic acrylamide compound, an acrylonitrile compound, a mono-epoxide compound, or combinations thereof.

36. The method of paragraph 34, wherein the monofunctional modifier is alkyl acrylate, acrylamide, alkyl acrylamide, dialkyl acrylamide, acrylonitrile, 2-alkyl oxirane, 2-(allyloxyalkyl)oxirane, hydroxyl A composition selected from alkyl acrylates, ω-(acryloyloxy)-alkyltrimethylammonium compounds, ω-(acrylamido)-alkyltrimethylammonium compounds, and any combinations thereof.

37. The composition of paragraph 34, wherein the monofunctional modifier comprises at least one of the following: methyl acrylate, alkyl acrylate, acrylamide, N-methylacrylamide, N,N-dimethylacrylamide, acrylonitrile. , 2-methyloxirane; 2-ethyloxirane, 2-propyloxirane, 2-(allyloxymethyl)oxirane, 2-hydroxyethyl acrylate, 2-(2-hydroxyethoxy)ethyl acrylate, 2-(acryloyl oxide) Si)-N,N,N-trimethylethanaminium, 3-(acryloyloxy)-N,N,N-trimethylpropane-1-aminium; 2-acrylamido-N,N,N-trimethylethanaminium, 3-acrylamido-N,N,N-trimethylpropane-1-aminium, and 1-isopropyl-3-(methacryloyl oxide Si)-1-methylazetidinium chloride.

38. The composition of paragraph 25, wherein the ratio of azetidinium ions to secondary amine moieties in the resin is from about 0.4 to about 1.0.

39. The composition of paragraph 25, wherein the concentration of 1,3-dichloro-2-propanol (1,3-DCP) is less than about 15,000 ppm.

40. The composition of paragraph 25, wherein the pH of the resin is adjusted using an acid.

41. The composition of paragraph 40, wherein the acid is acetic acid, formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, an organic or inorganic acid, or a combination thereof.

42. The composition of paragraph 40, wherein the pH of the resin is adjusted to about pH 2.0 to about pH 4.5.

43. The composition of paragraph 25, wherein the solids content of the resin is adjusted from about 10% to about 50%.

44. The composition of paragraph 25, wherein the resin has a charge density of from about 1.0 to about 4.0 mEq/g of solids.

45. A composition having at least three of the following characteristics: a) a charge density of about 1.0 to about 4.0 mEq/g of solids; b) the ratio of azetidinium ions to amide moieties in the resin is from about 0.5 to about 0.9; c) molecular weight of about 0.1 × 10 ⁶ to about 3.0 × 10 ⁶ ; d) azetidinium equivalents from about 1,800 to about 3,500; and e) a 1,3-dichloro-2-propanol (1,3-DCP) content of less than about 10,000 ppm when the solids content is about 25%.

46. Paper reinforced with the composition of any of paragraphs 25-45.

47. A method of treating paper to impart wet strength, comprising the step of treating the pulp fibers used to make the paper with a resin composition prepared by the following steps: a) Partially crosslinked polyamines by reacting the polyamines with a symmetrical crosslinking agent. producing a; b) adding epihalohydrin to the partially crosslinked polyamine to produce a halohydrin-functionalized polymer; and c) cyclizing the halohydrin-functionalized polymer to form a resin with azetidinium moieties.

48. A strength resin comprising a polyamine partially crosslinked with a bridging moiety and having azetidinium ions, wherein the bridging moiety is diisocyanate, 1,3-dialkyldiazetidine-2,4-dione, dianhydride A strength resin derived from a functionally symmetric crosslinker comprising water, diacyl halide, dienon, dialkyl halide, or any mixture thereof.

49. A method of reinforcing paper comprising the step of contacting fibers with a strength resin comprising a polyamine partially crosslinked with bridging moieties and having azetidinium ions, wherein the bridging moieties are diisocyanates, 1,3- A method derived from a functionally symmetric crosslinker comprising dialkyldiazetidine-2,4-dione, dianhydride, diacyl halide, dienon, dialkyl halide, or any mixture thereof.

50. A method for producing a strength resin comprising the following steps: reacting a polyamine and a functionally symmetrical crosslinker to produce a partially crosslinked polyamine, wherein the functionally symmetrical crosslinker is a diisocyanate, 1,3-dialkyl A step comprising diazetidine-2,4-dione, dianhydride, diacyl halide, dienon, dialkyl halide, or any mixture thereof; and reacting the partially crosslinked polyamine with epihalohydrin to produce a strength resin with azetidinium ions.

51. The strength resin or method of any of paragraphs 48-50, wherein the functionally symmetric crosslinker comprises a diisocyante.

52. The strength resin or method of any of paragraphs 48 to 51, wherein the diisocyanate is a blocked diisocyanate.

53. The strength resin or method of any of paragraphs 48 to 52, wherein the functionally symmetric crosslinker comprises 1,3-dialkyldiazetidine-2,4-dione.

54. The strength resin or method of any of paragraphs 48-53, wherein the functionally symmetric crosslinker comprises a dianhydride.

55. The strength resin or method of any of paragraphs 48-54, wherein the functionally symmetric crosslinker comprises a diacyl halide.

56. The strength resin or method of any of paragraphs 48-55, wherein the functionally symmetric crosslinker comprises a dienone.

57. The strength resin or method of any of paragraphs 48-56, wherein the functionally symmetric crosslinker comprises a dialkyl halide.

58. The method of any one of paragraphs 48 to 57, wherein the functionally symmetric crosslinking agent is a diacrylate compound, a bis(acrylamide) compound, a diepoxide compound, a polyazetidinium compound, N,N'-methylene-bis-methacryl. The strength resin or method further comprising an amide, poly(alkylene glycol) diglycidyl ether, or any mixture thereof.

59. The strength resin or method of any of paragraphs 48-58, wherein the polyamine comprises a polyamidoamine.

60. The strength resin or method of any one of paragraphs 48 to 59, wherein the azetidinium ion is formed by reaction of an epihalohydrin and a polyamine partially crosslinked with bridging moieties.

61. The strength resin or method of any of paragraphs 48-60, wherein the strength resin has a charge density of from 2.25 mEq/g of solids to 3.5 mEq/g of solids.

62. The strength resin or method of any of paragraphs 48-61, wherein the strength resin has an azetidinium equivalent weight of 2,000 to 3,500.

63. The strength resin or method of any of paragraphs 48-62, wherein the strength resin has a weight average molecular weight of 900,000 to 1,700,000.

64. The strength resin or method of any of paragraphs 48-63, wherein the strength resin contains less than 10,000 ppm 1,3-dichloro-2-propanol.

65. The method of any one of paragraphs 48-60, wherein the strength resin has a charge density of between 2.25 mEq/g of solids and 3.5 mEq/g of solids, an azetidinium equivalent weight of between 2,000 and 3,500, and a weight average molecular weight of between 900,000 and 1,700,000. , a strength resin or method containing less than 10,000 ppm of 1,3-dichloro-2-propanol.

66. The method of any one of paragraphs 48 to 65, wherein the functionally symmetric crosslinking agent is a di-acrylate compound, a bis(acrylamide) compound, a di-epoxide compound, a polyazetidinium compound, N,N'-methylene-bis- A strength resin or method further comprising methacrylamide, and poly(alkylene glycol) diglycidyl ether, or any mixtures thereof.

Certain implementations and features have been described using a set of upper numerical limits and a set of lower numerical limits. It is recognized that ranges including combinations of any two values, such as a combination of any upper value and an arbitrary lower value, a combination of any two lower values, and/or a combination of any two upper values, are considered unless otherwise indicated. It has to be. Specific lower limits, upper limits and ranges appear in one or more claims below. All values are expressed as “about” or “approximately” and take into account experimental errors and variations that would be expected by a person skilled in the art.

Various terms are defined above. To the extent that a term used in a claim is not limited above, the broadest definition given to that term by one of ordinary skill in the art as reflected in at least one printed publication or issued patent should be given. and, where applicable, the entire patents, test procedures, and other documents cited herein are fully incorporated by reference to the extent such disclosure is consistent with this application and for all jurisdictions in which such incorporation is permitted.

While the foregoing is directed to specific example implementations, other and further embodiments of the invention may be devised without departing from its basic scope, which scope is determined by the claims that follow.

Claims (20)

A strength resin comprising a polyamine partially crosslinked with a bridging moiety, wherein the polyamine partially crosslinked with a bridging moiety has an azetidinium ion, and the bridging moiety is 1,3-dialkyldiazety. A strength resin derived from a functionally symmetric crosslinker comprising dine-2,4-dione, dienon, or mixtures thereof. The method of claim 1, wherein the functionally symmetric crosslinking agent further comprises a di-acrylate compound, a bis(acrylamide) compound, a di-epoxide compound, a polyazetidinium compound, N,N'-methylene-bis-methacrylamide. , and poly(alkylene glycol) diglycidyl ether, diisocyanate, dianhydride, diacyl halide, or any mixture thereof. The strength resin of claim 1 , wherein the functionally symmetric crosslinking agent comprises the 1,3-dialkyldiazetidine-2,4-dione. The strength resin of claim 1 , wherein the functionally symmetric crosslinking agent comprises the dienone. The strength resin of claim 1 , wherein the functionally symmetric crosslinking agent further comprises a dialkyl halide. The strength resin of claim 1, wherein the polyamine comprises a polyamidoamine. The strength resin of claim 1, wherein the azetidinium ion is formed by reaction of the polyamine and epihalohydrin partially crosslinked with the bridging moiety. The strength resin of claim 1, wherein the polyamine partially crosslinked with bridging moieties has a charge density of from 2.25 mEq/g of solids to 3.5 mEq/g of solids. The strength resin of claim 1, wherein the polyamine partially crosslinked with bridging moieties has an azetidinium equivalent weight of 2,000 to 3,500. The strength resin of claim 1, wherein the polyamine partially crosslinked with bridging moieties has a weight average molecular weight of 900,000 to 1,700,000. The strength resin of claim 1, wherein the strength resin contains less than 10,000 ppm of 1,3-dichloro-2-propanol. 2. The method of claim 1, wherein the polyamine partially crosslinked with bridging moieties has a charge density of 2.25 mEq/g of solids to 3.5 mEq/g of solids, an azetidinium equivalent of 2,000 to 3,500, and a weight of 900,000 to 1,700,000. A strength resin having an average molecular weight, wherein the strength resin contains less than 10,000 ppm of 1,3-dichloro-2-propanol. Method for producing strength resin, comprising the following steps:
A step of producing a partially cross-linked polyamine by reacting a polyamine and a functionally symmetric cross-linking agent, wherein the functionally symmetric cross-linking agent is 1,3-dialkyldiazetidine-2,4-dione, dienone, or a mixture thereof. comprising: steps; and
Reacting the partially cross-linked polyamine with epihalohydrin to produce a partially cross-linked polyamine having azetidinium ions. 14. The method of claim 13, wherein the partially crosslinked polyamine having azetidinium ions has a charge density of 2.25 mEq/g of solids to 3.5 mEq/g of solids, an azetidinium equivalent weight of 2,000 to 3,500, and a weight of 900,000 to 1,700,000. average molecular weight, and wherein the strength resin contains less than 10,000 ppm of 1,3-dichloro-2-propanol. The method of claim 14, wherein the functionally symmetric crosslinking agent is further selected from a diacrylate compound, a bis(acrylamide) compound, a diepoxide compound, a polyazetidinium compound, N,N'-methylene-bis-methacrylamide, poly (alkylene glycol) diglycidyl ether, diisocyanate, dianhydride, diacyl halide, or any mixture thereof. A method of reinforcing paper comprising contacting fibers with a strength resin comprising a polyamine partially crosslinked with bridging moieties, wherein the polyamine partially crosslinked with bridging moieties has azetidinium ions, and The method of claim 1, wherein the ring moiety is derived from a functionally symmetric crosslinker comprising 1,3-dialkyldiazetidine-2,4-dione, dienon, or mixtures thereof.
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