WO2022123498A1 - Crosslinked polymer particles and related compositions and processes - Google Patents

Abstract

The crosslinked polymer particles include a plurality of pendent tertiary amine groups and at least 20 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles. Further particles include cores of crosslinked polymer particles having a plurality of tertiary amine groups and shells of an inorganic salt encapsulating the cores. The inorganic salt includes a multivalent cation and a multivalent anion. Compositions and articles including the particles and processes for making the particles and the crosslinked polymer particles are also described.

Description

CROSSLINKED POLYMER PARTICLES AND RELATED COMPOSITIONS AND PROCESSES

Cross-Reference to Related Application

This application claims priority to U.S. Provisional Application No. 63/123,947, filed December 10, 2020, the disclosure of which is incorporated by reference in its entirety herein.

Background

Many curable epoxy compositions are packaged as two-part compositions in which the epoxy resin is separated from the curing agent. Once mixed, the epoxy resin and the curing agent react at room temperature or elevated temperatures. Such two-part epoxy compositions have good storage stability, but the mixture of the epoxy resin and the curing agent is usable for only a limited time after mixing so that it is typically difficult to prepare a large amount of the mixture in advance. In addition, the two parts must be carefully measured so the stoichiometry of the epoxy resin and curing agent are appropriate.

Some one-part epoxy compositions are known in which a latent curing agent is used. Examples of such latent curing agents include dicyandiamide (DICY), amine salt, or modified imidazole compounds. Curing agents encapsulated in a polymeric shell are also known. Compared to two-part systems, one-part epoxy compositions are easy to use since no mixing is required. However, they are often not shelf stable under normal conditions and need to be stored and shipped in a refrigerator or freezer. Furthermore, the cure temperature is often limited by the melting point of the curing agent, which can exceed about 170 °C for conventional latent curing agent. Addition of a curing accelerator to such a one-part epoxy resin composition can decrease the cure temperature. Some latent curing agents including encapsulated curing agents are described in U.S. Pat. Nos. 5,593,759 (Vargas et al.), 5,883,193 (Karim), 6,506,494 (Brandys et al.), 7,645,514 (Watanabe et al.), 7,927,514 (Kondo et al.), and 9,067,395 (Plaut et al.) and Int. Pat. Appl. Pub. No. WO 2011/126702 (Liu et al.).

Summary

The present disclosure provides crosslinked polymer particles useful as curing agents for epoxy resins and other amine-curable polymers. In some embodiments, the crosslinked polymer particles are encapsulated by an inorganic salt. Such particles can be useful, for example, for providing amine-curable compositions having desirable storage stability that, in some embodiments, can be cured at a relatively low temperature (e.g., less than about 170 °C). In one aspect, the present disclosure provides crosslinked polymer particles having a plurality of pendent tertiary amine groups and at least 20 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles.

In another aspect, such particles are encapsulated by an inorganic salt. The inorganic salt includes a multivalent cation and a multivalent anion.

In another aspect, the present disclosure provides particles that include crosslinked polymer particles encapsulated by an inorganic salt. The crosslinked polymer particles include a plurality of tertiary amine groups. The inorganic salt includes a multivalent cation and a multivalent anion.

In another aspect, the present disclosure provides a composition of an amine-curable resin and any of the aforementioned particles dispersed therein.

In another aspect, the present disclosure provides a process of making the particles. The process includes combining the crosslinked polymer particles and an aqueous solution of a salt of a monovalent cation and the multivalent anion, removing water to provide crosslinked polymer particles coated with the salt of the monovalent cation and the multivalent anion, dispersing the coated crosslinked polymer particles in a solution of a salt including the multivalent cation and a monovalent anion in a solvent, and obtaining the particles including crosslinked polymer particles encapsulated by the inorganic salt of the multivalent cation and the multivalent anion.

In this application:

Terms such as "a", "an" and "the" are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one".

The phrase "comprises at least one of followed by a list refers to comprising any one of the items in the list and any combination of two or more items in the list. The phrase "at least one of followed by a list refers to any one of the items in the list or any combination of two or more items in the list.

The terms “cure” and “curable” refer to joining polymer chains together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network polymer. Therefore, in this disclosure the terms “cured” and “crosslinked” may be used interchangeably. A cured or crosslinked polymer is generally characterized by insolubility but may be swellable in the presence of an appropriate solvent.

The term “polymer or polymeric” will be understood to include polymers, copolymers (e.g., polymers formed using two or more different monomers), oligomers, and combinations thereof, as well as blends of polymers, oligomers, and/or copolymers.

"Alkyl group" and the prefix "alk-" are inclusive of both straight chain and branched chain groups and of cyclic groups. In some embodiments, alkyl groups have up to 30 carbons (in some embodiments, up to 20, 15, 12, 10, 8, 7, 6, or 5 carbons) unless otherwise specified. Cyclic groups can be monocyclic or polycyclic and, in some embodiments, have from 3 to 10 ring carbon atoms. Terminal “alkenyl” groups have at least 3 carbon atoms.

"Arylalkylene" refers to an "alkylene" moiety to which an aryl group is attached. "Alkylarylene" refers to an "arylene" moiety to which an alkyl group is attached.

The terms "aryl" and “arylene” as used herein include carbocyclic aromatic rings or ring systems, for example, having 1, 2, or 3 rings and optionally containing at least one heteroatom (e.g., O, S, or N) in the ring optionally substituted by up to five substituents including one or more alkyl groups having up to 4 carbon atoms (e.g., methyl or ethyl), alkoxy having up to 4 carbon atoms, halo (i.e., fluoro, chloro, bromo or iodo), hydroxy, or nitro groups. Examples of aryl groups include phenyl, naphthyl, biphenyl, fluorenyl as well as furyl, thienyl, pyridyl, quinolinyl, isoquinolinyl, indolyl, isoindolyl, triazolyl, pyrrolyl, tetrazolyl, imidazolyl, pyrazolyl, oxazolyl, and thiazolyl.

All numerical ranges are inclusive of their endpoints and non-integral values between the endpoints unless otherwise stated (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

Detailed Description

Crosslinked polymer particles of the present disclosure comprise a plurality of pendent tertiary amine groups. It will be understood by a person having ordinary skill in the art that a tertiary amine group is a neutral organic group represented by -NR.2. The R groups may be the same or different and may include alkyl or alkylene groups or aryl or arylene groups, for example. The nitrogen atom is understood to be neutral and to have a lone pair of electrons at neutral pH, features that distinguish a tertiary amine from a quaternary ammonium, which have a permanent positive charge regardless of pH.

In some embodiments, the crosslinked polymer particles comprise divalent units represented by formula -[CH2-C(R¹)-(Q-NR2)]-, wherein R¹ is hydrogen or methyl, and each R is independently alkyl (e.g., having up to 4 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl), hydroxalkylenyl (e.g., hydroxyethyl, hydroxypropyl, or hydroxybutyl), aryl, aryalkylene, or the two R groups together form a non-aromatic 5- to 8-membered ring that may be substituted or unsubstituted and may include at least one heteroatom (e.g., O, S, or N) in the ring. Suitable 5- to 8-membered rings include pyrrolidines, piperidines, morpholines, piperazines, and azepanes, and suitable substituents include one or more alkyl groups having up to 4 carbon atoms (e.g., methyl or ethyl), alkoxy having up to 4 carbon atoms, halo (i.e., fluoro, chloro, bromo or iodo), hydroxy, and nitro groups. In some embodiments, each R is methyl. Q is alkylene, arylene, alkylarylene, or arylalkylene, wherein alkylene, arylene, alkylarylene, and arylalkylene are each optionally interrupted or terminated with at least one of - O-, -C(O)-, -S(0)o-2-, -N(R')-, -SO₂N(R')-, -C(O)N(R')-, -C(O)-O-, -O-C(O)-, -OC(O)-N(R')-, -N(R)-C(O)-O-, or -N(R')-C(O)-N(R')-, wherein R' is hydrogen or alkyl having up to 4 carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl) and optionally substituted by hydoxyl. In some of these embodiments, R' is hydrogen. In some of these embodiments, R' is methyl or ethyl. The phrase "interrupted with at least one of -O-, -C(O)-, -S(0)o-2-, -N(R')-, -SC>2N(R')-, -C(O)N(R')-, -C(O)-O-, -O-C(O)-, -OC(O)-N(R')-, -N(R')-C(O)-O-, or -N(R)-C(O)-N(R)-" refers to having a portion of the alkylene, arylene, alkylarylene, and arylalkylene on either side of the -O-, -C(O)-, -S(0)o-2-, -N(R')-, -SO₂N(R)-, -C(O)N(R)-, -C(O)-O-, -O-C(O)-, -OC(O)-N(R)-, -N(R')-C(O)-O-, or -N(R')-C(O)-N(R')-. An example of alkylene that is interrupted with -O- is -CH2-CH2-O-CH2-CH2-. When Q is terminated by one of functional groups listed above, the terminal functional group is bonded to the carbon atom to which Q is attached, not the nitrogen atom of the amine. An example of alkylene that is terminated with -O- is -O-CH2-CH2-. In some embodiments, Q is alkylene, which may have, in some embodiments, up to 4, 3, or 2 carbon atoms, wherein the alkylene is terminated with -O-, -C(O)-O-, or -C(O)N(R')-.

In some embodiments, the crosslinked polymer particles comprise divalent units independently represented by formula:

In these divalent units, W is -O-, -S-, or -N(R’)-, wherein R’ is as defined above in any of its embodiments. In some embodiments, W is -O-. V is alkylene that is optionally interrupted by at least one ether linkage or amine linkage and optionally substituted by hydroxyl. In some embodiments, V is alkylene that is optionally interrupted by at least one ether linkage. In some embodiments, V is alkylene having 2 to 10, 2 to 8, 2 to 6, 3 to 6, 3 to 8, or 3 to 10 carbon atoms. In these divalent units, each R and R¹ is independently as defined above in any of the aforementioned embodiments of R and R¹. In some embodiments, including any of the aforementioned divalent units including tertiary amino groups, R¹ is methyl. In some embodiments, the divalent units are present in a range from 20 to 85, 25 to 85, 25 to 80, or 30 to 70 percent by weight, based on the total weight of the crosslinked polymer particles.

In some embodiments, the crosslinked polymer particles of the present disclosure are crosslinked with poly(alkyleneoxy) crosslinking segments. In some embodiments, the crosslinked polymer has at least 20 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles. In some embodiments, the crosslinked polymer has at least 30 or 40 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles. In some embodiments, the crosslinked polymer has up to 70, 60, or 50 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles. In some embodiments, the crosslinked polymer particles comprise poly(alkyleneoxy) crosslinking segments represented by formulas X and XI, wherein R¹ is hydrogen or methyl, (in some embodiments, hydrogen and in some embodiments, methyl). EO represents -CH2CH2O-. Each R³O is independently selected from the group consisting of-CH(CH3)CH2O-, -CH2CH2CH2O-, -CH2CH(CH3)O-, -CH2CH2CH2CH2O-, -CH(CH₂CH3)CH₂O-, -CH₂CH(CH₂CH3)O-, and -CH₂C(CH₃)2O-. In some embodiments, each R³O independently represents -CH(CH3)CH2O- or -CH2CH(CH3)O-). Each p is independently a value from 0 to 150 (in some embodiments, from 7 to about 130, or from 14 to about 130); and each q is independently a value from 0 to 150 (in some embodiments, from about 20 to about 100, 1 to 55, or from about 9 to about 25). The sum p + q is at least 1 (in some embodiments, at least 5, 10, or 20.) In some embodiments, the ratio p/q has a value from at least 0.5, 0.75, 1 or 1.5 to 2.5, 2.7, 3, 4, 5, or more. In formulas X and XI, each Q’ is independently -O-, -C(O)-, -S(0)o-2-, -N(R')-, -SC>2N(R')-, -C(O)N(R')-, -C(O)-O-, -O-C(O)-, -OC(O)-N(R')-, -N(R')-C(O)-O-, or -N(R')-C(O)-N(R')-, wherein R’ is as defined above in any of its embodiments. In some embodiments, each Q’ is independently -O-, -C(O)-O-, or -C(O)N(R')-.

XI

In some embodiments, the poly(alkyleneoxy) crosslinking segments are represented by formula:

wherein R¹, EO, R³O, p, and q are as defined above in any of their embodiments. Other divalent units may be present in the crosslinked polymer particles. In some embodiments, the crosslinked polymer particles comprise hydroxyl-substituted divalent units represented by formula -[CH2-C(R¹)-(Q-OH)]- or -[CH2-C(R¹)-(C(O)-O-V-OH)]-, wherein R¹, Q, and V are as defined above in any of their embodiments. In some embodiments, Q is alkylene, which may have, in some embodiments, up to 4, 3, or 2 carbon atoms that is terminated with -O-, -C(O)-O-, or -C(O)N(R')-. Hydroxyl substituted divalent units may be present in up to 20, 15, 10, or 5% by weight, based on the total weight of the crosslinked polymer particles. Other suitable divalent units for the crosslinked polymer particles include those having pendant poly(alkyleneoxy) groups rather than poly(alkyleneoxy) crosslinking segment.

The various divalent units described above can be connected together in a random or block fashion. In some embodiments, the crosslinked polymer particles have a random distribution of tertiary amine groups, poly(alkyleneoxy) segment, and other divalent units.

The crosslinked polymer particles are a reaction product of at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds. The at least one ethylenically unsaturated monomer comprising a tertiary amine group can be represented by formula CH2=C(R¹)-Q-NR2 and R2N-V-W-C(O)-C(R¹)=CH2, wherein R¹, Q, R, W, and V are as defined above in any of their embodiments. The at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds can be represented by

wherein R¹, Q’, EO, R³O, p, and q are as defined above in any of their embodiments. Combinations more than one ethylenically unsaturated monomer comprising a tertiary amine group and/or more than one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds can be useful.

Some ethylenically unsaturated monomers represented by formula R2N-V-W-C(O)-C(R¹)=CH2, wherein R, V, W, and R¹ are as defined above, are available, for example, from commercial sources (e.g., 2-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl methacrylate, 3-(dimethylamino)propyl acrylate, N-[3 -(dimethylamino)-propyl]methacrylamide, N-[2-(N,N-dimethylamino)propyl]acrylamide, N-[2-(N,N-dimethylamino)propyl]methacrylamide, 2-(tert-butylamino)ethyl methacrylate, 2- diisopropylaminoethylacrylate, 2-diisopropylaminoethyl methacrylate, 2-N-morpholinoethyl acrylate, and 2-N-morpholinoethyl (meth)acrylate from Millipore Sigma (St. Louis, Mo.) or other chemical suppliers). Others monomers represented by formula R2N-V-W-C(O)-C(R¹)=CH2 can be prepared using conventional techniques. Combinations of any of these monomers may also be useful. Some alkyleneoxy-containing polymerizable compounds having at least two carbon-carbon double bonds are commercially available (e.g., polyoxyalkylene glycol diacrylates (e.g., diethylene glycol diacrylate, diethylene glycol dimethacrylate, tri(ethylene glycol) diacrylate, tri(ethylene glycol) dimethacrylate, and tri(ethylene glycol) divinyl ether). Polyethylene glycol dimethacrylates and diacrylates with a variety of weight average molecular weights can be obtained from Sartomer Company, Inc., Exton, Pa. Combinations of any of these monomers may also be useful.

The crosslinked polymer particles can include a reaction product of at least one ethylenically unsaturated monomer comprising a hydroxyl group. Some suitable ethylenically unsaturated monomers can be represented by formula HO-V-W-C(O)-C(R¹)=CH2, wherein V, W, and R¹ are as defined above. Suitable examples of hydroxyl functional ethylenically unsaturated monomers include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, caprolactone mono(meth)acrylate, available under the trade designation “SR-495B” from Sartomer and other poly(e- caprolactone) mono[2-(meth)acryloxy ethyl] esters, poly (e -caprolactone) mono[2-acryloxy ethyl] esters, glycerol di(meth)acrylate, l-(acryloxy)-3-(methacryloxy)-2-propanol, 4-hydroxycyclohexyl (meth)acrylate, 2-hydroxy-3-alkyloxy(meth)acrylate, polyethylene glycol mono(meth)acrylate, monomethoxy polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, monomethoxy polypropylene glycol mono(meth)acrylate, CH2=CHC(O)O(CH2CH2O)7-9H available, for example, from Nippon Oil & Fats Company, Tokyo, Japan under the trade designation "BLEMMER"), and pentaerythritol triacrylate. In some embodiments, two or more different hydroxy functional (meth)acryl monomers may be utilized in the preparation of the crosslinked polymer particles.

Other ethylenically unsaturated monomers may be useful in the preparation of the crosslinked polymer particles. Examples of useful monomers include alkyl (meth)acrylate esters and alkyl (meth)acrylamides and (meth)acrylates and (meth)acrylamides including other functional groups. In some embodiments, poly(alkyleneoxy) monomers such as methoxy diethylene glycol methacrylate, methoxy triethylene glycol methacrylate, methoxy tetraethylene glycol methacrylate, or butoxy diethylene glycol methacrylate may be useful.

In some embodiments each ethylenically unsaturated monomer useful in the preparation of the crosslinked polymer particles is a methacrylate monomer.

The ethylenically unsaturated monomers can be polymerized by various free-radical polymerization techniques. In some embodiments, the polymer comprising tertiary amine groups is prepared by solventless radiation polymerization, including processes using electron beam, gamma, and ultraviolet light radiation. In some embodiments, the crosslinked polymer particles prepared by emulsion polymerization in a diluent. One method of preparing the polymer comprises combining of at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds in a diluent and polymerizing the at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds by free radical polymerization to provide the crosslinked polymer particles. In this method, the polymerization can be conducted in the absence of (e.g. unpolymerizable) organic solvents. The concentration of the resulting polymer comprising a tertiary amine group may be 5% to 90%, 10% to 90%, or 30% to 90%, based on the total weight of the polymer and diluent.

In some embodiments, the monomer mixture further comprises a photoinitiator. Useful photoinitiators include benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether; substituted acetophenones such as 2, 2-dimethoxy-2 -phenylacetophenone photoinitiator, available the trade name “IRGACURE 651” or “ESACURE KB-1” photoinitiator (Sartomer Co., West Chester, Pa.), bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide available under the trade designation “IRGACURE 819” and dimethylhydroxyacetophenone; substituted a-ketols such as 2- methyl -2 -hydroxy propiophenone; aromatic sulfonyl chlorides such as 2-naphthalene-sulfonyl chloride; and photoactive oximes such as 1 -phenyl- l,2-propanedione-2-(O-ethoxy-carbonyl)oxime.

Examples of useful photoinitiators include photoactive compounds that undergo a Norrish I cleavage to generate free radicals that can initiate by addition to the acrylic double bonds. Such polymerizable photoinitiators are described, for example, in U.S. 5,902,836 and 5,506,279 (Gaddam et al.).

Photoinitiator(s) are typically present in an amount from 0.05 to 1.0 weight percent (wt.%) based on the total weight of the monomers. The photoinitiator may be present, for example, in a range from 0. 1 to 0.5 wt.%.

The composition including the diluent and monomer mixture may be irradiated with actinic (e.g. ultraviolet (UV)) radiation to polymerize the ethylenically unsaturated monomer(s). UV light sources can be of various types including relatively low light intensity sources such as blacklights, which provide generally 10 mW/cm² or less (as measured in accordance with procedures approved by the United States National Institute of Standards and Technology as, for example, with a UVIMAP UM 365 L-S radiometer manufactured by Electronic Instrumentation & Technology, Inc., in Sterling, Va.) over a wavelength range of 280 to 400 nanometers; and relatively high light intensity sources such as medium pressure mercury lamps which provide intensities generally greater than 10 mW/cm², in some embodiments, in a range from 15 to 450 mW/cm². Intensities can range from 0.1 to 150 mW/cm², 0.5 to 100 mW/cm², or from 0.5 to 50 mW/cm². The monomer component(s) can also be polymerized with high intensity light sources as available from Fusion UV Systems Inc. UV light to polymerize the monomer component(s) can be provided by light emitting diodes, blacklights, medium pressure mercury lamps, or a combination thereof.

Before polymerization the monomer mixture can form a discontinuous phase dispersed within a continuous phase of the diluent. The monomer mixture is typically a liquid at ambient temperature (25 °C). In some embodiments, the ethylenically unsaturated monomers are liquids, which may be miscible with one another. In other embodiments, if one of the ethylenically unsaturated monomers is a liquid and the other is a solid, the solid ethylenically unsaturated monomer is typically soluble in the liquid ethylenically unsaturated monomer.

The diluent is generally a liquid material at ambient temperature (25 °C) that does not covalently bond with a tertiary amine. In some embodiments, the diluent may be characterized by a pH of at least about 6. In some embodiments, the pH is in a range from about 6 to about 7.5. In some embodiments, the diluent is hydroxyl -functional or thiol-functional. The hydroxy or thiol functional groups of the diluent can aid in stabilizing the suspension. In some embodiments, the diluent is glycerol. In some embodiments, the diluent is an aqueous polymer solution such as an aqueous starch or a derivatized cellulose (e.g., hydroxypropylmethylcellulose, carboxymethylcellulose, or methyl cellulose) solution.

In some embodiments, the ethylenically unsaturated groups of the monomer(s) polymerize to form a copolymer having an acrylic or methacrylic backbone. The acrylic or methacrylic backbone comprises one or more pendent tertiary amine groups. In embodiments in which the crosslinked polymer particles comprise a poly(alkyleneoxy) segment, the poly(alkyleneoxy) tends to compatibilize the polymer with a diluent containing hydroxyl groups or water. In embodiments in which the crosslinked polymer particles comprise methacrylate groups, the crosslinked polymer particles tend to disperse better in a diluent containing hydroxyl groups or water than when the crosslinked polymer particles comprise acrylate groups. The crosslinked polymer particles are desirably suspended or dispersed within the diluent.

In some embodiments, the diluent further comprises a dispersant. Suitable dispersants include anionic surfactants (e.g., sulfates, sulfonates, phosphates, carboxylates, and sulfates of polyethoxylated derivatives of straight or branched chain aliphatic alcohols and carboxylic acids), cationic surfactants (e.g., quaternary ammonium salts), amphoteric surfactants (e.g., sultaines, betaines, and sulfobetaines), and nonionic surfactants. In some embodiments, the dispersant is a nonionic surfactant. Suitable nonionic surfactants include alkyl polyglucosides (e.g., obtained under the trade designation “APG 325”, from BASF SE, Ludwigshafen, Germany), alkyl glucosides (e.g., blend of decyl and undecyl glucoside), fatty amine ethoxylates, fatty alcohol ethoxylates, fatty acid alkanolamides, castor oil ethoxylates, alcohol ethoxylates/propoxylates, and combinations thereof.

The dispersant may be present in the diluent in any suitable amount to keep the crosslinked particle particles dispersed in the diluent. In some embodiments, the dispersant is present in a range from 0.5% to 20% by weight, 0.5% to 15% by weight, or 1% to 10% by weight, based on the weight of the crosslinked polymer particles.

One of ordinary skill in the art appreciates that a dispersion is a system in which discrete particles of one material are dispersed in a continuous phase of another material. The two phases may be in the same or different states of matter. A suspension is a heterogeneous mixture that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye, usually must be larger than 1 micrometer, and typically eventually settle.

The size of the dispersed crosslinked polymer particles comprising a tertiary amine group can vary. In some embodiments, the dispersed polymer may have an average particle or droplet size of at least 0.1, 0.5, or 1 micrometer. In some embodiments, the average particle or droplet size is no greater than 1 mm (1000 micrometers). In some, the average particle or droplet size is no greater than 900, 800, 700, 600, 500, 400, 300, 200, or 100 micrometers. In some embodiments, the average particle or droplet size is no greater than 90, 80, 70, 60, 50, 40, 30, 20, or 10 micrometers. In some embodiments, the diluent comprises at least 5, 10, 15, 20, 25, or 30 wt.% of the crosslinked polymer particles described herein. The amount of crosslinked polymer particles in the diluent can range up to about 50 wt.%.

In some embodiments of the present disclosure, particles comprise an inorganic salt comprising a multivalent cation and a multivalent anion encapsulating the crosslinked polymer particles described above in any of their embodiments. The term “encapsulating” refers to at least a major portion (that is, greater than 50%) of the surface of a crosslinked polymer particle is covered by the inorganic salt. In some embodiments, at least 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% of the surface of the crosslinked polymer particle is covered by the inorganic salt. In some embodiments, the inorganic salt completed surrounds the surface of the crosslinked polymer particle. A variety of multivalent cations can be useful for the inorganic salt. In some embodiments, the multivalent cation comprises at least one of calcium, barium, magnesium, zinc, aluminum, or strontium. In some embodiments, the multivalent cation is an alkaline earth metal. In some embodiments, the multivalent cation is calcium. In some embodiments, the multivalent anion comprises at least one of sulfate, phosphate, hydrogen phosphate, or carbonate. In some embodiments, the multivalent anion comprises carbonate. In some embodiments, the inorganic salt comprises at least one of magnesium carbonate, calcium carbonate, zinc carbonate, calcium sulfate, magnesium sulfate, or calcium phosphate. In some embodiments, the inorganic salt comprises at least one of calcium carbonate, calcium phosphate, or calcium sulfate.

The present disclosure also comprises a process of making the particles including the crosslinked polymer particles encapsulated by an inorganic salt comprising a multivalent cation and a multivalent anion. The process includes combining the crosslinked polymer particles as described above in any of their embodiments and an aqueous solution of an inorganic salt of a monovalent cation and the multivalent anion. The multivalent anion can be any of those described above, in some embodiments, sulfate, phosphate, hydrogen phosphate, or carbonate. The monovalent cation can be an alkali metal cation or ammonium. In some embodiments, the monovalent cation comprises at least one of sodium, potassium, or ammonium. In some embodiments, the inorganic salt of the monovalent cation and the multivalent anion is disodium hydrogen phosphate, sodium carbonate, potassium carbonate, or ammonium carbonate. The crosslinked polymer particles can be mixed with the aqueous solution in an amount up to 20% by weight, up to 15% by weight, and up to 10% by weight, or at least 1% by weight, at least 2% by weight, or at least 3% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution. In some embodiments, the crosslinked polymer particles are present with the aqueous solution in an amount from 1% to 20% by weight, 1% to 15% by weight, 2% to 10% by weight, or 3% to 10% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution. The inorganic salt of a monovalent cation and the multivalent anion can be dissolved in the aqueous solution in an amount up to 25% by weight, up to 20% by weight, up to 15% by weight, and up to 10% by weight, or at least 1% by weight, at least 2% by weight, or at least 3% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution. In some embodiments, the inorganic salt of a monovalent cation and the multivalent anion is in the aqueous solution in an amount from 1% to 20% by weight, 5% to 20% by weight, 5% to 15% by weight, or 10% to 20% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution. Conveniently, the crosslinked polymer particles and the aqueous solution can be mixed at room temperature.

In some embodiments, the aqueous solution further comprises a dispersant. Suitable dispersants include anionic surfactants (e.g., sulfates, sulfonates, phosphates, carboxylates, and sulfates of polyethoxylated derivatives of straight or branched chain aliphatic alcohols and carboxylic acids), cationic surfactants (e.g., quaternary ammonium salts), amphoteric surfactants (e.g., sultaines, betaines, and sulfobetaines), and nonionic surfactants. In some embodiments, the dispersant is a nonionic surfactant. Suitable nonionic surfactants include alkyl polyglucosides (e.g., obtained under the trade designation “APG 325”, from BASF SE, Ludwigshafen, Germany), alkyl glucosides (e.g., blend of decyl and undecyl glucoside), fatty amine ethoxylates, fatty alcohol ethoxylates, fatty acid alkanolamides, castor oil ethoxylates, alcohol ethoxylates/propoxylates, and combinations thereof.

The dispersant may be present in the aqueous solution in any suitable amount to keep the crosslinked polymer particles dispersed in the aqueous solution. In some embodiments, the dispersant is present in a range from 0.05% to 10% by weight, 0.5% to 5% by weight, or 1% to 5% by weight, based on the weight of the crosslinked polymer particles.

In some embodiments, the aqueous solution further comprises a monovalent anion. The monovalent anion can be, in some embodiments, hydrogen sulfate, dihydrogen phosphate, or bicarbonate. The monovalent anion can be added to the aqueous solution using a further inorganic salt which has a monovalent cation and the monovalent anion. The monovalent cation can be an alkali metal cation or ammonium. In some embodiments, the monovalent cation comprises at least one of sodium, potassium, or ammonium. In some embodiments, the inorganic salt of the monovalent cation and the monovalent anion is sodium bicarbonate, potassium bicarbonate, or ammonium bicarbonate. The inorganic salt of a monovalent cation and the monovalent anion can be dissolved in the aqueous solution in an amount up to 20% by weight, up to 15% by weight, and up to 10% by weight, or at least 1% by weight, at least 2% by weight, or at least 3% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution. In some embodiments, the inorganic salt of a monovalent cation and the monovalent anion is in the aqueous solution in an amount from 1% to 20% by weight, 1% to 15% by weight, 2% to 10% by weight, or 3% to 10% by weight, based on the total weight of the crosslinked polymer particles and the aqueous solution.

The process of the present disclosure includes removing water to provide crosslinked polymer particles coated with the salt of the monovalent cation and the multivalent anion. Removing water can be carried out by any suitable method, for example, fdtering, evaporation, centrifugation, or a combination thereof. In some embodiments, removing water includes centrifugation of the reaction mixture and discarding the supernatant liquid.

The process of the present disclosure further includes dispersing the coated crosslinked polymer particles in a solution of a salt comprising the multivalent cation and a monovalent anion in a solvent. The multivalent cation can be any of those described above, for example, at least one of calcium, barium, magnesium, zinc, aluminum, or strontium. In some embodiments, the multivalent cation is an alkaline earth metal. In some embodiments, the multivalent cation is calcium. Suitable monovalent anions include halides (e.g., chloride, bromide, and iodide), acetate, and combinations thereof. In some embodiments, the monovalent anion is chloride. In some embodiments, the salt comprising the multivalent cation and a monovalent anion is calcium chloride. The salt of a multivalent cation and the monovalent anion can be dissolved in the solvent in an amount up to 20% by weight, up to 15% by weight, and up to 10% by weight, or at least 1% by weight, at least 2% by weight, or at least 5% by weight, based on the total weight of the solution. In some embodiments, the salt of a multivalent cation and the monovalent anion is in the solvent in an amount from 1% to 20% by weight, 1% to 15% by weight, 5% to 15% by weight, or 5% to 10% by weight, based on the total weight of the solution (that is, salt in solvent).

In the solution of a salt comprising the multivalent cation and a monovalent anion in a solvent, the solvent can comprise at least one of organic solvent or water. Suitable organic solvents include aliphatic alcohols (e.g., methanol, ethanol, and isopropanol); ketones (e.g., acetone, 2-butanone, and 2- methyl-4-pentanone); esters (e.g., ethyl acetate, butyl acetate, and methyl formate); ethers (e.g., diethyl ether, diisopropyl ether, methyl t-butyl ether, 2-methoxypropanol, and dipropyleneglycol monomethylether (DPM)); and combinations thereof In some embodiments, the organic solvent is methanol, ethanol, isopropanol, or a mixture thereof. In some embodiments, the organic solvent is isopropanol. In some embodiments, the solvent is water. Conveniently, the crosslinked polymer particles and the solution can be mixed at room temperature.

Conventional techniques are useful for obtaining the particles comprising the crosslinked polymer particles with the inorganic salt comprising the multivalent cation and the multivalent anion encapsulating the crosslinked polymer particles. Isolating the crosslinked polymer particles can be carried out, for example, by removing the solvent after treatment with the solution of multivalent cation and monovalent anion. Removing solvent can be carried out by any suitable method, for example, filtering, evaporation, centrifugation, or a combination thereof. In some embodiments, removing solvent includes centrifugation of the reaction mixture and discarding the supernatant liquid. The particles of the present disclosure can optionally be washed (e.g., with distilled water) and dried at ambient pressure or reduced pressure.

Particles of the present disclosure can have a range of useful sizes. In some embodiments, the particles have a median particle size (D50) in a range from 0. 1 micrometers to 1000 micrometers. The median size is also called the D50 size, where 50 percent by volume of the particles in the distribution are smaller than the indicated size. In some embodiments, the median particle size is at least 0.1 micrometer, at least 0.5 micrometer, or at least 1 micrometer. In some embodiments, the median particle size of the particles is up to 250 micrometers, 200 micrometers, or 150 micrometers. The median particle size can be determined by scanning electron microscopy or light scattering. For the purposes of determining particle size when the size is at least one micrometer, the median particle size is typically determined by light scattering. For particles that are asymmetric, the median particle size refers to the largest dimension of the particles.

The present disclosure provides a composition including an amine-curable polymer and the crosslinked polymer particles and/or particles of the present disclosure in any of their embodiments. The particles of the present disclosure in any of their embodiments can be dispersed within the composition. The composition can be a sealant or an adhesive, for example, a structural adhesive. In some embodiments, the composition includes an epoxy, which may be homopolymerized or cured with a polyamine- or polythiol curative. In some embodiments, the composition includes an isocyanate and may include a polyamine, polythiol, or polyol curative. In some embodiments, the composition includes a Michael acceptor, which may be cured with a polyamine- or polythiol curative. In some embodiments, the amine-curable polymer is an epoxy resin.

A variety of epoxy resins are useful in the composition according to the present disclosure. A monomeric polyepoxide may be an alkylene, arylene, alkylarylene, arylalkylene, or alkylenearylalkylene having at least two epoxide groups, wherein any of the alkylene, alkylarylene, arylalkylene, or alkylenearylalkylene are optionally interrupted by one or more ether (i.e., -O-), thioether (i.e., -S-), or amine (i.e., -NR¹-) groups and optionally substituted by alkoxy, hydroxyl, or halogen (e.g., fluoro, chloro, bromo, iodo). Useful monomeric polyepoxides may be diepoxides or polyepoxides with more than 2 (in some embodiments, 3 or 4) epoxide groups. An epoxy resin may be prepared by chain-extending any of such polyepoxides. It should be understood that the epoxy resin has reactive epoxide groups that can be cured, for example, by a tertiary amine catalyst.

Epoxy compounds useful for the compositions of the present disclosure include aromatic polyepoxide resins (e.g., a chain-extended diepoxide or novolac epoxy resin having at least two epoxide groups) and aromatic monomeric diepoxides. A crosslinkable epoxy resin typically will have at least two epoxy end groups. The aromatic poly epoxide or aromatic monomeric diepoxide typically contains at least one (in some embodiments, at least 2, in some embodiments, in a range from 1 to 4) aromatic ring that is optionally substituted by a halogen (e.g., fluoro, chloro, bromo, iodo), alkyl having 1 to 4 carbon atoms (e.g., methyl or ethyl), or hydroxyalkyl having 1 to 4 carbon atoms (e.g., hydroxymethyl). For epoxy resins containing two or more aromatic rings, the rings may be connected, for example, by a branched or straight-chain alkylene group having 1 to 4 carbon atoms that may optionally be substituted by halogen (e.g., fluoro, chloro, bromo, iodo).

Examples of aromatic epoxy resins useful in the compositions of the present disclosure include novolac epoxy resins (e.g., phenol novolacs, ortho-, meta-, or para-cresol novolacs or combinations thereof), bisphenol epoxy resins (e.g., bisphenol A, bisphenol F, halogenated bisphenol epoxies, and combinations thereof), resorcinol epoxy resins, tetrakis phenylolethane epoxy resins and combinations of any of these. Useful epoxy compounds include diglycidyl ethers of difunctional phenolic compounds (e.g., p,p’ -dihydroxydibenzyl, p,p'-dihydroxydiphenyl, p,p'-dihydroxyphenyl sulfone, p,p'- dihydroxybenzophenone, 2, 2'-dihydroxy- 1,1 -dinaphthylmethane, and the 2,2', 2,3', 2,4', 3,3', 3,4', and 4,4' isomers of dihydroxydiphenylmethane, dihydroxydiphenyldimethylmethane, dihydroxydiphenylethylmethylmethane, dihydroxydiphenylmethylpropylmethane, dihydroxydiphenylethylphenylmethane, dihydroxydiphenylpropylphenylmethane, dihydroxydiphenylbutylphenylmethane, dihydroxydiphenyltolylethane, dihydroxydiphenyltolylmethylmethane, dihydroxydiphenyldicyclohexylmethane, and dihydroxy diphenylcyclohexane.) In some embodiments, the adhesive includes a bisphenol diglycidyl ether, wherein the bisphenol (i.e., -O-CgHs-CFE-CgHs-O-) may be unsubstituted (e.g., bisphenol F), or either of the phenyl rings or the methylene group may be substituted by one or more halogens (e.g., fluoro, chloro, bromo, iodo), methyl groups, trifluoromethyl groups, or hydroxymethyl groups.

Examples of aromatic monomeric diepoxides useful in the curable compositions according to the present disclosure include the diglycidyl ethers of bisphenol A and bisphenol F and mixtures thereof. Bisphenol epoxy resins, for example, may be chain extended to have any desirable epoxy equivalent weight. Chain extending epoxy resins can be carried out by reacting a monomeric diepoxide, for example, with a bisphenol in the presence of a catalyst to make a linear polymer.

In some embodiments, the aromatic epoxy resin (e.g., either a bisphenol epoxy resin or a novolac epoxy resin) may have an epoxy equivalent weight of at least 150, 170, 200, or 225 grams per equivalent. In some embodiments, the aromatic epoxy resin may have an epoxy equivalent weight of up to 2000, 1500, or 1000 grams per equivalent. In some embodiments, the aromatic epoxy resin may have an epoxy equivalent weight in a range from 150 to 2000, 150 to 1000, or 170 to 900 grams per equivalent. In some embodiments, the first epoxy resin has an epoxy equivalent weight in a range from 150 to 450, 150 to 350, or 150 to 300 grams per equivalent. Epoxy equivalent weights may be selected, for example, so that the epoxy resin may be used as a liquid or solid, as desired. For some applications, it may be useful to incorporate a flexible, non-aromatic chain into the crosslinked epoxy network. In some cases, non-aromatic epoxy resins can be useful as reactive diluents that may help control the flow characteristics of the composition. A non-aromatic epoxy useful in the compositions of the present disclosure can include a branched or straight-chain alkylene group having 1 to 20 carbon atoms optionally interrupted with at least one -O- and optionally substituted by hydroxyl. In some embodiments, the non-aromatic epoxy can include a poly(oxyalkylene) group having a plurality (x) of oxyalkylene groups, OR¹, wherein each R¹ is independently C2 to C5 alkylene, in some embodiments, C2 to C3 alkylene, x is 2 to about 6, 2 to 5, 2 to 4, or 2 to 3. To become crosslinked into a network, useful non-aromatic epoxy resins will typically have at least two epoxy end groups. Examples of useful non- aromatic epoxy resins include glycidyl epoxy resins such as those based on diglycidyl ether compounds comprising one or more oxyalkylene units. Examples of these include resins made from ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, propanediol diglycidyl ether, butanediol diglycidyl ether, and hexanediol diglycidyl ether. Other useful non-aromatic epoxy resins include a diglycidyl ether of cyclohexane dimethanol, a diglycidyl ether of neopentyl glycol, a triglycidyl ether of trimethylolpropane, and a diglycidyl ether of 1,4-butanediol. In some embodiments, the non-aromatic epoxy is present at up to 20 (in some embodiments, 15, 10, 9, 8, 7, 6, or 5) percent by weight, based on the total weight of epoxy resin in the composition.

Cured aromatic epoxies (that is, epoxy polymers) as described herein will be understood to be preparable by crosslinking aromatic epoxy resins. The crosslinked aromatic epoxy typically contains a repeating unit with at least one (in some embodiments, at least 2, in some embodiments, in a range from 1 to 4) aromatic ring (e.g., phenyl group) that is optionally substituted by one or more halogens (e.g., fluoro, chloro, bromo, iodo), alkyl groups having 1 to 4 carbon atoms (e.g., methyl or ethyl), or hydroxyalkyl groups having 1 to 4 carbon atoms (e.g., hydroxymethyl). For repeating units containing two or more aromatic rings, the rings may be connected, for example, by a branched or straight-chain alkylene group having 1 to 4 carbon atoms that may optionally be substituted by halogen (e.g., fluoro, chloro, bromo, iodo).

Several amine-curable epoxy resins useful in the curable composition according to the present disclosure are commercially available. For example, several epoxy resins of various classes and epoxy equivalent weights are available from Dow Chemical Company, Midland, Mich.; Momentive Specialty Chemicals, Inc., Columbus, OH; Huntsman Advanced Materials, The Woodlands, Tex.; and Nan Ya Plastics Corporation, Taipei City, Taiwan. Examples of commercially available glycidyl ethers include diglycidylethers of bisphenol A (e.g. those available under the trade designations “EPON 828”, “EPON 1001”, “EPON 1310” and “EPON 1510” from Hexion Specialty Chemicals GmbH, Rosbach, Germany, those available under the trade designation “D.E.R.” from Dow Chemical Co. (e.g., D.E.R. 331, 332, and 334), those available under the trade designation “EPICLON” from Dainippon Ink and Chemicals, Inc. (e.g., EPICLON 840 and 850) and those available under the trade designation “YL-980” from Japan Epoxy Resins Co., Ltd.); diglycidyl ethers of bisphenol F (e.g. those available under the trade designation “EPICLON” from Dainippon Ink and Chemicals, Inc. (e.g., “EPICLON 830”)); polyglycidyl ethers of novolac resins (e.g., novolac epoxy resins, such as those available under the trade designation “D.E.N.” from Dow Chemical Co. (e.g., D.E.N. 425, 431, and 438)); and flame retardant epoxy resins (e.g., “D.E.R. 580”, a brominated bisphenol type epoxy resin available from Dow Chemical Co.). Examples of commercially available non-aromatic epoxy resins include the glycidyl ether of cyclohexane dimethanol, available from Hexion Specialty Chemicals GmbH, under the trade designation “HELOXY MODIFIER 107”.

The composition of the present disclosure may include a wide variety of components useful, for example, in sealant and adhesive compositions. For example, the composition can include at least one of toughening agents (e.g., acrylic core/shell polymers; styrene-butadiene/methacrylate core/shell polymers; polyether polymers; carboxyl- or amino-terminated acrylonitrile/butadienes; carboxylated butadienes, and polyurethanes), plasticizers (e.g., aliphatic and aromatic hydrocarbons, alkyl esters, alkyl ethers, aryl esters, and aryl ethers), curing agents (e.g., polyamines and polythiols), corrosion inhibitors, UV stabilizers, antioxidants, flame retardants, thixotropic agents such as fumed silica, dyes, pigments (e.g., ferric oxide, brick dust, carbon black, and titanium oxide), reinforcing agents (e.g., silica, magnesium sulfate, calcium sulfate, and beryllium aluminum silicate), clays such as bentonite, other suitable fdler (e.g., glass beads, talc, and calcium metasilicate), dispersing agents, wetting agents, adhesion promoters (e.g., silane coupling agents), antistatic agents, thermally and/or electrically conductive particles, foaming agents, and hollow polymeric or ceramic microspheres (e.g., glass bubbles).

Compositions of the present disclosure may be used, for example, to bond a first substrate to a second substrate to provide a bonded article. Many types of substrates may be bonded with compositions of the present disclosure such as metal (e.g., stainless steel or aluminum), glass (e.g., which may be coated with indium tin oxide), a polymer (e.g., a plastic, rubber, thermoplastic elastomer, or thermoset), or a composite. A composite material may be made from any two or more constituent materials with different physical or chemical properties. When the constituents are combined to make a composite, a material having characteristics different from the individual components is typically achieved. Some examples of useful composites include fiber-reinforced polymers (e.g., carbon fiber reinforced epoxies and glass-reinforced plastic); metal matrix compositions, and ceramic matrix composites. Useful polymeric substrates that can be bonded include polymers such as polyolefins (polypropylene, polyethylene, high density polyethylene, blends of polypropylene), polyamide 6 (PA6), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), PC/ABS blends, polyvinyl chloride (PVC), polyamide (PA), polyurethane (PUR), thermoplastic elastomers (TPE), polyoxymethylene (POM), polystyrene, poly(methyl) methacrylate (PMMA), and combinations thereof. The substrate may also include a metal coating on such polymers. The composition of the present disclosure can be useful, for example, for bonding electronic articles and automotive and aerospace components.

In some embodiments, a first substrate may be bonded to a second substrate by applying the composition of the present disclosure to at least a portion of one surface of the first substrate, covering the composition at least partially with at least a portion of one surface of the second substrate, and allowing the composition to cure. While it is not practical to enumerate a particular curing temperature suitable for all situations, generally suitable temperatures are in a range from about 30 °C to about 200 °C. In some embodiments, the composition of the present disclosure can be heated at 60 °C to 170 °C, 80 °C to 160 °C, or 100 °C to 150 °C, for at least 15, 30, 45, 60, 90, or 120 minutes, for example, to cure the composition.

In recent years, low-temperature curing and fast curing have become more and more desirable, particularly in the field of electronics assembly and plastic bonding applications, where bonding of thermally sensitive substrates occurs. Low-temperature curing can reduce thermal stresses due to CTE (coefficient of thermal expansion) mismatch. Fast curing can improve productivity. As shown in the Examples below, the crosslinked polymer particles and the crosslinked polymer particles encapsulated by an inorganic salt can cure an amine-curable resin, for example, an epoxy resin, at a relatively low temperature (e.g., less than about 170 °C).

Compositions that can cure at relative low temperatures often have the complication of a short storage time before they must be used. Composition Examples 4 and 5, which include crosslinked polymer particles encapsulated by an inorganic salt advantageously can be stored at 23 °C for greater than three months. Unexpectedly, these compositions can be stored for at least about one month or, in some embodiments, greater than two months at an elevated temperature of 49 °C. In contrast, a composition including latent amine curatives was cured within 14 days at 49 °C.

Some Embodiments of the Disclosure

In a first embodiment, the present disclosure provides crosslinked polymer particles comprising a plurality of pendent tertiary amine groups and at least 20 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles.

In a second embodiment, the present disclosure provides the crosslinked polymer particles of the first embodiment, further comprising a plurality of hydroxyl groups.

In a third embodiment, the present disclosure provides the crosslinked polymer particles of the first or second embodiment, wherein the crosslinked polymer particles are acrylic or methacrylic crosslinked polymer particles.

In a fourth embodiment, the present disclosure provides the crosslinked polymer particles of any one of the first to third embodiments, wherein the crosslinked polymer particles are a reaction product of: at least one ethylenically unsaturated monomer comprising a tertiary amine group; and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds.

In a fifth embodiment, the present disclosure provides the crosslinked polymer particles of the fourth embodiment, wherein each ethylenically unsaturated monomer is a methacrylate monomer.

In a sixth embodiment, the present disclosure provides the crosslinked polymer particles of any one of the first to fourth embodiments, wherein the crosslinked polymer particles comprise divalent units independently represented by formula:

5 wherein

W is -O-, -S-, or -N(R’)-, wherein R’ is alkyl having 1 to 4 carbon atoms;

V is alkylene that is optionally interrupted by at least one ether linkage or amine linkage and optionally substituted by hydroxyl; each R is independently alkyl, hydroxalkylenyl, aryl, arylalkylenyl, or the two R groups together form a non-aromatic 5- to 8-membered ring that may be substituted or unsubstituted and may include at least one O, S, or N in the ring; and

R¹ is hydrogen or methyl.

In a seventh embodiment, the present disclosure provides the crosslinked polymer particles of any one of the first to fourth and sixth embodiments, wherein the poly(alkyleneoxy) crosslinking segments are represented by formula:

wherein each R¹ is independently hydrogen or methyl;

EO represents -CH2CH2O-; each R³O is independently selected from the group consisting of-CH(CH3)CH2O-, -CH₂CH₂CH₂O-, -CH₂CH(CH₃)O-, -CH₂CH₂CH₂CH₂O-, -CH(CH₂CH₃)CH₂O-

-CH₂CH(CH₂CH₃)O- and -CH₂C(CH₃)₂O-; each p is independently a value from 0 to 150; and each q is independently a value from 0 to 150, wherein the sum p + q is at least 1.

In an eighth embodiment, the present disclosure provides the crosslinked polymer particles of any one of the first to seventh embodiments, wherein crosslinked polymer particles further comprise divalent units represented by formula -[CH₂-C(R¹)-(C(O)-O-V-OH)]-, wherein

V is alkylene that is optionally interrupted by at least one ether linkage or amine linkage and optionally substituted by hydroxyl; and

R¹ is hydrogen or methyl.

In a ninth embodiment, the present disclosure provides the crosslinked polymer particles of any one of the sixth to eighth embodiments, wherein each R¹ is methyl.

In a tenth embodiment, the present disclosure provides the crosslinked polymer particles of any one of the first to ninth embodiments, prepared by emulsion polymerization in a diluent.

In an eleventh embodiment, the present disclosure provides the crosslinked polymer particles of the tenth embodiment, wherein the diluent comprises at least one of glycerol or an aqueous starch or derivatized cellulose solution.

In a twelfth embodiment, the present disclosure provides particles comprising the crosslinked polymer particles of any one of the first to eleventh embodiments encapsulated with an inorganic salt comprising a multivalent cation and a multivalent anion.

In a thirteenth embodiment, the present disclosure provides particles comprising: crosslinked polymer particles comprising a plurality of tertiary amine groups; and an inorganic salt comprising a multivalent cation and a multivalent anion encapsulating the crosslinked polymer particle.

In a fourteenth embodiment, the present disclosure provides the particles of the twelfth or thirteenth embodiments, wherein the multivalent cation comprises at least one of calcium, barium, magnesium, zinc, or aluminum.

In a fifteenth embodiment, the present disclosure provides the particles of any one of the twelfth to fourteenth embodiments, wherein the multivalent anion comprises at least one of sulfate, phosphate, hydrogen phosphate, or carbonate.

In a sixteenth embodiment, the present disclosure provides the particles of any one of the twelfth to fifteenth embodiments, wherein the inorganic salt comprises at least one of calcium carbonate, calcium phosphate, or calcium sulfate. In a seventeenth embodiment, the present disclosure provides the particles of any one of the thirteenth to fifteenth embodiments, wherein the crosslinked polymer particles further comprise poly(alkyleneoxy) crosslinking segments.

In an eighteenth embodiment, the present disclosure provides the particles of any one of the thirteenth to seventeenth embodiments, wherein the crosslinked polymer particles further comprise a plurality of hydroxyl groups.

In a nineteenth embodiment, the present disclosure provides the particles of any one of the thirteenth to eighteenth embodiments, wherein the crosslinked polymer particles are acrylic or methacrylic crosslinked polymer particles.

In a twentieth embodiment, the present disclosure provides the particles of any one of the thirteenth to nineteenth embodiments, wherein the crosslinked polymer particles are a reaction product of: at least one ethylenically unsaturated monomer comprising a tertiary amine group; and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds.

In a twenty-first embodiment, the present disclosure provides the particles of the twentieth embodiment, wherein each ethylenically unsaturated monomer is a methacrylate monomer.

In a twenty-second embodiment, the present disclosure provides the particles of any one of the thirteenth to twentieth embodiments, wherein the crosslinked polymer particles comprise divalent units independently represented by formula:

wherein

W is -O-, -S-, or -N(R’)-, wherein R’ is alkyl having 1 to 4 carbon atoms;

V is alkylene that is optionally interrupted by at least one ether linkage or amine linkage and optionally substituted by hydroxyl; each R is independently alkyl, hydroxalkylenyl, aryl, arylalkylenyl, or the two R groups together form a non-aromatic 5- to 8-membered ring that may be substituted or unsubstituted and may include at least one O, S, or N in the ring; and

R¹ is hydrogen or methyl.

In a twenty-third embodiment, the present disclosure provides the particles of any one of the thirteenth to twentieth and twenty-second embodiments, wherein the poly(alkyleneoxy) crosslinking segments are represented by formula:

wherein each R¹ is independently hydrogen or methyl;

EO represents -CH2CH2O-; each R³O is independently selected from the group consisting of-CH(CH₃)CH2O-, -CH2CH2CH2O-, -CH₂CH(CH₃)O- -CH2CH2CH2CH2O-, -CH(CH₂CH₃)CH₂O-, -CH₂CH(CH₂CH₃)O-, and -CH₂C(CH₃)₂O-; each p is independently a value from 0 to 150; and each q is independently a value from 0 to 150, wherein the sum p + q is at least 1.

In a twenty-fourth embodiment, the present disclosure provides the particles of any one of the thirteenth to twenty-third embodiments, wherein crosslinked polymer particles further comprise divalent units represented by formula -[CH2-C(R¹)-(C(O)-O-V-OH)]-, wherein

V is alkylene that is optionally interrupted by at least one ether linkage or amine linkage and optionally substituted by hydroxyl; and

R¹ is hydrogen or methyl.

In a twenty-fifth embodiment, the present disclosure provides the particles of any one of the twenty-second to twenty-fourth embodiments, wherein each R¹ is methyl.

In a twenty-sixth embodiment, the present disclosure provides a composition comprising an amine-curable resin and the particles or crosslinked polymer particles of any one of the first to twentyfifth embodiments dispersed therein.

In a twenty-seventh embodiment, the present disclosure provides a composition comprising an epoxy resin and the particles or crosslinked polymer particles of any one of the first to twenty-fifth embodiments dispersed therein.

In a twenty-eighth embodiment, the present disclosure provides the composition of the twentyseventh embodiment, wherein the epoxy resin comprises an aromatic epoxy resin having at least two epoxy functional groups. In a twenty-ninth embodiment, the present disclosure provides the composition of the twentyeighth embodiment, wherein the epoxy resin further comprises at least one of a non-aromatic epoxy resin or a hydroxy-functional curative.

In a thirtieth embodiment, the present disclosure provides a process of making the particles of any one of the thirteenth to twenty-fifth embodiments, the process comprising: combining the crosslinked polymer particles and an aqueous solution of an inorganic salt of a monovalent cation and the multivalent anion; removing water to provide crosslinked polymer particles coated with the salt of the monovalent cation and the multivalent anion; dispersing the coated crosslinked polymer particles in a solution of a salt comprising the multivalent cation and a monovalent anion in a solvent; and obtaining the particles comprising the crosslinked polymer particles and the inorganic salt comprising the multivalent cation and the multivalent anion encapsulating the crosslinked polymer particles.

In a thirty-first embodiment, the present disclosure provides the process of the thirtieth embodiment, wherein the aqueous solution further comprises a dispersant.

In a thirty-second embodiment, the present disclosure provides the process of the thirtieth or thirty-first embodiment, wherein the aqueous solution further comprises a monovalent anion.

In a thirty-third embodiment, the present disclosure provides the process of the thirty-second embodiment, wherein the monovalent anion is bicarbonate, hydrogen sulfate, or dihydrogen phosphate.

In a thirty-fourth embodiment, the present disclosure provides the process of any one of the thirtieth to thirty-third embodiments, wherein the solvent comprises at least one of any alcohol or water.

In a thirty-fifth embodiment, the present disclosure provides the process of any one of the thirtieth to thirty-fourth embodiments, further comprising: combining of at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds in a diluent; and polymerizing the at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds by free radical polymerization to provide the crosslinked polymer particles.

In a thirty-sixth embodiment, the present disclosure provides the process of the thirty-fifth embodiment, wherein each ethylenically unsaturated monomer is a methacrylate monomer.

In a thirty-seventh embodiment, the present disclosure provides the process of the thirty-fifth or thirty-sixth embodiment, wherein the ethylenically unsaturated monomer comprising a tertiary amine group comprises at least one of 2-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl methacrylate, 3- (dimethylamino)propyl acrylate, N-[3-(dimethylamino)-propyl]methacrylamide, N-[2-(N,N- dimethylamino)propyl]acrylamide, N-[2-(N,N-dimethylamino)propyl]methacrylamide, 2-(tert- butylamino)ethyl methacrylate, 2-diisopropylaminoethylacrylate, 2-diisopropylaminoethyl methacrylate, 2-N-morpholinoethyl methacrylate or 2-N-morpholinoethyl acrylate.

In a thirty-eighth embodiment, the present disclosure provides the process of any one of the thirty-fifth to thirty-seventh embodiments, wherein the ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds comprises at least one of polyoxyalkylene glycol diacrylate, polyoxyalkylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tri(ethylene glycol) diacrylate, tri(ethylene glycol) dimethacrylate, and tri (ethylene glycol) divinyl ether).

In a thirty-ninth embodiment, the present disclosure provides the process of any one of the thirtyfifth to thirty-eighth embodiments, further comprising isolating the crosslinked polymer particles before combining the crosslinked polymer particles and the aqueous solution of the inorganic salt of the monovalent cation and the multivalent anion.

In order that this disclosure can be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting this disclosure in any manner.

EXAMPLES

Objects and advantages of this disclosure are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight, and all reagents used in the examples were obtained, or are available, from general chemical suppliers such as, for example, Sigma-Aldrich, St. Louis, MO, or may be synthesized by conventional methods. The following abbreviations are used in this section: ft = feet, cm = centimeters, in = inches, g = grams, lbs = pounds, °C = degrees Celsius, °F = degrees Fahrenheit, J = Joules, mm = millimeter, mb = milliliter, rpm = revolutions per minute, and min = minutes.

Table 1: Materials Used in the Examples

Examples 1 to 3: Particles

Example 1

Part A

A first mixture of 100 g DMAEMA, 20 g HEMA, and 80 g SR603OP was added to 270 mg IGRACURE 819. The first mixture was stirred vigorously for 20 minutes at room temperature (18 °C to 20 °C). A second mixture was made by adding 750 g glycerol to 30 g APG 325. The first mixture was then added to the second mixture, and they were shear mixed together for 20 minutes using a VWR ELITE MAX blade mixer (Company, Location ).

The mixture was then poured in a large “ZIPLOC” (trade designation of S.C. Johnson and Son, Inc.) bag and cured with ultraviolet light for 10 to 15 minutes with a 100 watt, long-wavelength BLACK RAY UV lamp (UVP, LLC, Upland, CA), situated at about 15 cm (6 in) from the surface of the bag.

The cured mixture was then dispersed in excess water (2,000 mL), shaken for 30 minutes with a Gyratory Shaker, New Brunswick Scientific, New York, and centrifuged at 3,000 rpm in an EPPENDORF 5810 R centrifuge (Eppendorf, Hamburg, Germany). The supernatant was removed, and the resulting particles were then re-suspended in 1,000 mL of water for a second rinse, followed by centrifugation at 3000 rpm for three minutes. After this, the particles were suspended in 500 mL isopropyl alcohol in a plastic bottle, shaken on the Gyratory Shaker for 20 minutes, and then filtered through #1 Whatman Filter Paper. The particles were then air dried. Secondary electron imaging (SEI), SEM images were obtained using a JEOL 700 IF Field Emission Scanning Electron Microscope (JEOL USA, Inc., Peabody, MA). Part B

Disodium phosphate heptahydrate (40 g) and 1.6 g of sodium hydroxide were dissolved in 200 g of deionized water. The particles from Part A (10 g), ethanol (1 g), and 1.7 g of surfactant solution “APG 325” (10% solids in water), were added. The mixture was blended for 2 minutes using a very high shear rotary blender, Model IKA T50 Ultra Turrax (IKA, Wilmington, NC). The blended mixture was then shaken for 15 minutes using the Gyratory Shaker. The mixture was then centrifugated at 4,000 rpm using a centrifuge, Model EPPENDORF 5810 R (Eppendorf North America, Enfield, CT). The supernatant was discarded and the sedimented part was transferred to a solution of 20 g calcium chloride in 100 g ethanol. The mixture was then blended for about 3 minutes using the rotary blender. The blended dispersion was then shaken for 5 minutes using the Gyratory Shaker and then left to sit for about 15 minutes at 20 °C. This blended dispersion was then centrifugated at 4,000 rpm. The supernatant was then discarded. The sedimented part was then resuspended in distilled water, shaken for 15 minutes using a Gyratory Shaker (New Brunswick Scientific Co., Enfield, CT) then and filtered using #1 Whatman Filter Paper). The resulting particles were then air dried. Secondary electron imaging (SEI), SEM images were obtained using a JEOL 700 IF Field Emission Scanning Electron Microscope (JEOL USA, Inc., Peabody, MA). A comparison of the SEM images of Part A and Part B particles indicated that the Part A particles had been encapsulated in Part B.

Example 2

Example 2 was prepared as described in Example 1, Parts A and B, with the modification that the first mixture in Part A was made by adding 100 g DMAEMA and 100 g SR603OP to 270 mg IGRACURE 819.

Example 3

Example 3 was prepared as described in Example 1, Part A, with the modification that the first mixture in Part A was made by adding 100 g DMAEMA and 100 g SR603OP to 270 mg IGRACURE 819. Part B was not carried out so that the Example 3 particles were not encapsulated by an inorganic salt. The SEM and size distribution of the Example 3 particles were non-distinguishable from the Example 1, Part A particles.

Examples 4 to 6 and Illustrative Example 1: Epoxy Compositions

Examples 4 to 6 and Illustrative Example 1 were prepared by using the materials and amounts (in parts by weight) shown in Table 2, adding these materials to a Max 100 SPEEDMIXER cup ( Flacktek, Inc; Landrum, SC), and mixing at 1,500 rpm for 2 minutes using a DAC 600 FVZ SPEEDMIXER (Flacktek, Inc) to obtain an uncured epoxy resin composition.

Table 2: Examples 4 to 6 and Illustrative Example 1: Epoxy Compositions

Uncured epoxy resin Examples 4 to 6 and Illustrative Example 1 (Ill. Ex. 1) were evaluated using the Shelf Life Evaluation and the DSC measurements described below to evaluate curing behavior and glass transition temperature (Tg). The results are shown in Table 3, below.

Table 3: Shelf Life Evaluations and DSC measurements

Shelf Life Evaluation

Shelf life of uncured compositions was determined by means of viscosity measurements. The viscosity of the curable filled epoxy resin was measured by a shear rate sweep using an Ares G2 Rheometer (TA Instruments, New Castle, DE) in the cone and plate mode of operation. The measurements were taken at 25°C (77°F) using a 25 millimeters (mm) diameter stainless steel cone with a cone angle of 0.099 radians and a 50 mm plate. Two to three grams of curable resin composition were placed between the cone and plate. The cone and plate were then closed to provide a 0.465 mm gap (at the tip) filled with resin. Excess resin was scraped off the edges with a spatula. Viscosity was measured using a shear rate sweep from 20 to 0. 1 Hertz and the viscosity change over time at 4.1 Hertz was monitored. Measurements were made periodically, during which time the samples were stored at either 23-25°C (73-79°F) or in an oven at 49°C (120°F). The test was discontinued if the viscosity reached a value that was quadruple that of the initial value measured. This time was designated as the shelf life of the compositions.

DSC Measurements - Thermal Properties of Uncured and Cured Resin Compositions Differential scanning calorimetry (DSC) was performed using a Model Q2000 DSC (TA

Instruments, New Castle, DE) and evaluated using the TA Universal Analysis Software Package. A sample of uncured resin weighing between 4 and 20 milligrams was placed in an aluminum pan, weighed, and sealed. The sample was then heated at a rate of 10°C/minute from 0°C to 250°C, followed by cooling at 20°C/minute down to -50°C, then reheating at a rate of 5°C/minute, back up to 250°C. In this manner the cure onset temperature, cure peak temperature, and heat of cure energy of the uncured resins were determined during the first heat cycle; and glass transition temperature (Tg) of the cured resins was determined during the second heat cycle. The Tg was taken as the inflection point of the thermal transition. Various modifications and alterations of this disclosure may be made by those skilled the art without departing from the scope and spirit of the disclosure, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.

Claims

What is claimed is:

1. Crosslinked polymer particles comprising a plurality of pendent tertiary amine groups and at least 20 percent by weight poly(alkyleneoxy) crosslinking segments, based on the total weight of the crosslinked polymer particles.

2. Crosslinked polymer particles of claim 1 further comprising a plurality of hydroxyl groups.

3. Crosslinked polymer particles of claim 1 or 2, wherein the crosslinked polymer particles are a reaction product of: at least one ethylenically unsaturated monomer comprising a tertiary amine group; and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds.

4. Crosslinked polymer particles of claim 3, wherein each ethylenically unsaturated monomer is a methacrylate monomer.

5. Particles comprising the crosslinked polymer particles of any one of claims 1 to 4 encapsulated by an inorganic salt comprising a multivalent cation and a multivalent anion.

6. Particles comprising: crosslinked polymer particles comprising a plurality of tertiary amine groups; and an inorganic salt comprising a multivalent cation and a multivalent anion encapsulating the crosslinked polymer particles.

7. Particles of claim 5 or 6, wherein the multivalent cation comprises at least one of calcium, barium, magnesium, zinc, or aluminum, and wherein the multivalent anion comprises at least one of sulfate, phosphate, hydrogen phosphate, or carbonate.

8. Particles of any one of claims 5 to 7, wherein the inorganic salt comprises at least one of calcium carbonate, calcium phosphate, or calcium sulfate.

9. Particles of any one of claims 6 to 8, wherein the crosslinked polymer particles further comprise poly (alkyleneoxy) segments.

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10. Particles of any one of claims 6 to 9, wherein the crosslinked polymer particles further comprise a plurality of hydroxyl groups.

11. A composition comprising an amine-curable resin and the particles of any one of claims 1 to 10 dispersed therein.

12. The composition of claim 11, wherein the amine-curable resin is an epoxy resin.

13. A process of making the particles of any one of claims 5 to 10, the process comprising: combining the crosslinked polymer particles and an aqueous solution of an inorganic salt of a monovalent cation and the multivalent anion; removing water to provide crosslinked polymer particles coated with the salt of the monovalent cation and the multivalent anion; dispersing the coated crosslinked polymer particles in a solution of a salt comprising the multivalent cation and a monovalent anion in a solvent; and obtaining the particles comprising the crosslinked polymer particles and the inorganic salt comprising the multivalent cation and the multivalent anion encapsulating the crosslinked polymer particles.

14. The process of claim 13, wherein the aqueous solution further comprises a dispersant, and wherein the solvent comprises an alcohol.

15. The process of claim 13 or 14, further comprising: combining of at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds in a diluent; and polymerizing the at least one ethylenically unsaturated monomer comprising a tertiary amine group and at least one ethylenically unsaturated monomer comprising at least one poly(alkyleneoxy) segment and at least two carbon-carbon double bonds by free radical polymerization to provide the crosslinked polymer particles.