Component addition polymerization

Abstract

A method of making a collection of polymeric beads is provided, wherein the beads comprise (i) 75 to 99 weight percent, based on the weight of the beads, of polymerized units of a monofunctional vinyl monomer, and (ii) 1 to 25 weight percent, based on the weight of the beads, of polymerized units of a multifunctional vinyl monomer, wherein the method comprises (a) providing an aqueous suspension of monomer droplets comprising an initiator, a monofunctional vinyl monomer, and a multifunctional vinyl monomer; (b) initiating polymerization of the monomers in the monomer droplets; (c) adding a monomer feed solution to the suspension while polymerization of the monomers in the monomer droplets is occurring.

Description

[0001] One useful method for producing polymer beads is suspension polymerization, which involves suspending monomer droplets in an aqueous medium and then polymerizing the monomers within the droplets to form polymer beads. When a monomer mixture is present in the monomer droplets, it is known that the monomers typically react at different rates, resulting in non-uniform polymer beads. For example, it is anticipated that one or more regions within the droplet may form copolymers with a higher proportion of polymeric units of more reactive monomers than the average proportion of more reactive monomers present in the monomer mixture throughout the droplet. Such regions rich in polymeric units of more reactive monomers are expected to form particularly early in the polymerization process. Further, it is anticipated that regions with relatively weaker polymeric units of more reactive monomers will form later in the polymerization process. Therefore, the resulting polymer beads are expected to be non-uniform, with some polymer segments within the beads having different concentrations of polymeric units of more reactive monomers than other polymer segments. This non-uniformity is expected to be detrimental to some performance characteristics of the polymer beads.

[0002] It is desirable to provide a method for preparing polymer beads, the method comprising polymerizing a mixture of monomers to obtain polymer beads in which the distribution of polymeric units of each monomer is relatively uniform. More generally, it is further desirable to provide a method by which the degree and nature of non-uniformity can be controlled, rather than relying solely on the relative reactivity of the monomers to produce uncontrolled non-uniformity. It is also desirable to provide a method in which the mass transfer of monomers fed into the monomer droplets in which polymerization is taking place during polymerization proceeds effectively or uniformly or effectively and uniformly, wherein “uniformly” means that the mass transfer proceeds unusually nearly identically from batch (i.e., one polymerization process) to another.

[0003] In many cases, after polymerization, the polymer beads are functionalized. That is, the polymer beads are subjected to one or more chemical reactions to attach ionic functional groups to the polymer beads, which can be anionic or cationic groups.

[0004] A key property of polymer beads is their mechanical strength. The mechanical strength of polymer beads can be assessed immediately after polymerization, or it can be assessed for functionalized beads. The mechanical strength of the beads can be measured directly, for example, by measuring the force required to crush them. Higher crushing strength is desirable, especially for functionalized beads. Furthermore, the mechanical strength of the beads can be measured by exposing polymer beads functionalized with anionic or cationic groups to alternating solutions containing different types of ions. Exposure to these alternating solutions induces osmotic stress, which can cause some polymer beads to break. It is desirable to minimize the number of functionalized beads that break due to osmotic stress.

[0005] US 3,792,029 describes a suspension polymerization method in which an emulsion containing a highly reactive monomer is added to the suspension during the polymerization of a monomer mixture. It is desirable to provide a method in which pure monomers are added to the suspension polymerization process. It is also desirable to provide polymer beads having one or more of the following advantages: relatively uniform distribution of polymeric units of the monomers, high crushing strength, consistent and / or efficient mass transfer of monomers into monomer droplets, and / or high resistance to permeation stress.

[0006] Furthermore, in the method described in US 3,792,029, the emulsion added to the suspension during polymerization contains a mixture of more reactive monomers and less reactive monomers. In the mixture added to the suspension as described in US 3,792,029, there is a significantly greater (by weight) amount of less reactive monomers compared to the more reactive monomers. It is believed that the method described in US 3,792,029 can lead to one or more of the following undesirable effects: the method may result in an increase in bead size, which imposes undesirable stress on the polymer network; and / or the method may result in the formation of inhomogeneities in the bead structure, for example, by forming an interpenetrating polymer network. It is desirable to provide a method in which the monomers added to the suspension during polymerization are 50% by weight or more of the more reactive monomers. It is also desirable to provide a method that avoids the undesirable effects of the method in US 3,792,029.

[0007] The following is a statement of the present invention.

[0008] A first aspect of the present invention is a method for preparing polymer bead assemblies, wherein the beads comprise

[0009] (i) Based on the weight of the beads, 75 to 99% by weight of a polymerization unit of monofunctional vinyl monomers, and

[0010] (ii) Based on the weight of the beads, 1 to 25% by weight of a polymer unit of a multifunctional vinyl monomer.

[0011] The method includes

[0012] (a) Provide an aqueous suspension containing monomer droplets comprising an initiator, a monofunctional vinyl monomer, and a polyfunctional vinyl monomer;

[0013] (b) Initiating polymerization of monomers in the monomer droplets;

[0014] (c) Simultaneously with the polymerization of the monomers in the monomer droplets, a monomer feed solution is added to the suspension.

[0015] The monomers are added when the degree of polymerization (EXTSTART) in the monomer droplets is between 0% and 50%, and

[0016] The addition is terminated when the degree of monomer polymerization (EXTSTOP) in the monomer droplets is between 5% and 100% after EXTSTART;

[0017] The feed solution contains a monomer in an amount of 90% to 100% by weight based on the weight of the feed solution;

[0018] The feed solution contains a polyfunctional vinyl monomer in an amount of 50% to 100% by weight based on the weight of the feed solution.

[0019] A second aspect of the present invention is a method for preparing polymer bead assemblies, wherein the beads comprise

[0020] (i) Based on the weight of the beads, 75 to 99% by weight of a polymerization unit of monofunctional vinyl monomers, and

[0021] (ii) Based on the weight of the beads, 1 to 25% by weight of a polymer unit of a multifunctional vinyl monomer.

[0022] Within each bead, the average molar concentration of the polymerization unit of the multifunctional vinyl monomer per cubic micrometer is MVAV;

[0023] Within each bead, T1000 is a sequence of 1,000 uniquely linked polymeric monomer units;

[0024] Wherein, within each T1000, MVSEQ is the weight percentage of the polymerization unit of the polyfunctional vinyl monomer, based on the weight of T1000;

[0025] Where MVRATIO = MVSEQ / MVAV;

[0026] and

[0027] 90% or more of the beads are uniform beads, wherein uniform beads are 90% or more of all T1000 sequences having an MVRATIO of 1.5 or less.

[0028] A third aspect of the invention is a method for treating water, wherein the water contains dissolved ions, the ions including undesirable cations, wherein the method includes...

[0029] (a) Providing a functionalized polymer bead assembly comprising

[0030] (i) Based on the weight of the beads, 75 to 99% by weight of a polymerization unit of monofunctional vinyl monomers, and

[0031] (ii) Based on the weight of the beads, 1 to 25% by weight of a polymer unit of a multifunctional vinyl monomer.

[0032] (iii) Functional groups that are bound to polymer beads and have a charge opposite to that of the undesirable ions, and

[0033] (iv) Ions that are not bound to polymer beads and have the same charge as the undesirable ions;

[0034] Within each bead, the average molar concentration of the polymerization unit of the multifunctional vinyl monomer per cubic micrometer is MVAV;

[0035] Within each bead, T1000 is a sequence of 1,000 uniquely linked polymeric monomer units;

[0036] Wherein, within each T1000, MVSEQ is the weight percentage of the polymerization unit of the polyfunctional vinyl monomer, based on the weight of T1000;

[0037] Where MVRATIO = MVSEQ / MVAV;

[0038] and

[0039] 90% or more of the beads are uniform beads, wherein uniform beads are 90% or more of all T1000 sequences having an MVRATIO of 1.5 or less.

[0040] (b) The water is then passed through a bed of polymer bead aggregates to exchange unwanted ions for ions (iv).

[0041] (c) The regenerated solution containing dissolved ions (v) of the same kind as ions (iv) is then passed through a bed of the polymer bead assembly to exchange ions (v) for undesirable ions.

[0042] A fourth aspect of the present invention is a method for producing 2,2-bis(4-hydroxyphenyl)propane, comprising condensing phenol with acetone in the presence of an acid catalyst to produce dihydroxyphenol 2,2-bis(4-hydroxyphenyl)propane.

[0043] The acid catalyst comprises an assembly of sulfonated polymer beads, wherein the sulfonated polymer beads comprise

[0044] (i) Based on the weight of the beads, 75 to 99% by weight of a polymerization unit of monofunctional vinyl monomers, and

[0045] (ii) Based on the weight of the beads, 1 to 25% by weight of a polymer unit of a multifunctional vinyl monomer.

[0046] Within each bead, the average molar concentration of the polymerization unit of the multifunctional vinyl monomer per cubic micrometer is MVAV;

[0047] Within each bead, T1000 is a sequence of 1,000 uniquely linked polymeric monomer units;

[0048] Wherein, within each T1000, MVSEQ is the weight percentage of the polymerization unit of the polyfunctional vinyl monomer, based on the weight of T1000;

[0049] Where MVRATIO = MVSEQ / MVAV;

[0050] and

[0051] 90% or more of the beads are uniform beads, wherein uniform beads are 90% or more of all T1000 sequences having an MVRATIO of 1.5 or less.

[0052] The following is a detailed description of the present invention.

[0053] As used herein, unless the context clearly indicates otherwise, the following terms have the specified definitions.

[0054] As used herein, a “polymer” is a relatively large molecule composed of reaction products of smaller chemical repeating units. Polymers may have structures that are linear, branched, star-shaped, cyclic, hyperbranched, cross-linked, or combinations thereof; polymers may have a single type of repeating unit (“homopolymer”) or they may have more than one type of repeating unit (“copolymer”). Copolymers may have various types of repeating units arranged randomly, sequentially, in blocks, or in other arrangements, or any mixture or combination thereof.

[0055] In this paper, molecules that can react with each other to form repeating units of a polymer are called "monomers". The repeating units formed in this way are called "polymer units" of monomers.

[0056] Vinyl monomers have a structure Where R 1 R 2 R 3 and R 4 Each vinyl monomer is independently hydrogen, halogen, aliphatic group (e.g., alkyl group), substituted aliphatic group, aryl group, substituted aryl group, another substituted or unsubstituted organic group, or any combination thereof. Vinyl monomers are capable of free radical polymerization to form polymers. Some vinyl monomers have a bond to R 1 R 2 R 3 and R 4A vinyl monomer contains one or more polymerizable carbon-carbon double bonds; such vinyl monomers are referred to herein as polyfunctional vinyl monomers. A vinyl monomer having exactly one polymerizable carbon-carbon double bond is referred to herein as a monofunctional vinyl monomer.

[0057] Styrene monomers are vinyl monomers as follows, wherein R 1 and R 2 Each is hydrogen, R 3 It is hydrogen or alkyl and -R 4 It has the following structure

[0058]

[0059] Where R 5 R 6 R 7 R 8 and R 9 Each of these groups is independently hydrogen, halogen, aliphatic group (e.g., alkyl or vinyl group), substituted aliphatic group, aryl group, substituted aryl group, another substituted or unsubstituted organic group, or any combination thereof.

[0060] The reaction between monomers to form one or more polymers is referred to as polymerization in this paper.

[0061] As used herein, an initiator is a molecule that is stable under ambient conditions but capable of generating one or more radical fragments under certain conditions, and said fragments are capable of interacting with monomers to initiate a radical polymerization process. Conditions leading to the generation of radical fragments include, for example, elevated temperatures, participation in redox reactions, exposure to ultraviolet and / or ionizing radiation, or combinations thereof.

[0062] As used herein, the phrase “total monomers” refers to all monomers used to prepare the polymer, including those present when polymerization is initiated and all monomers that may be added during polymerization.

[0063] In this paper, polymers are considered to contain polymeric units of the monomers used to prepare the polymer, even if some or all of these polymeric units are altered after polymerization by the addition of one or more functional groups. For example, a copolymer prepared from styrene and DVB in a styrene:DVB weight ratio of 90:10 is considered to have 90% by weight styrene polymeric units. If this copolymer is subsequently altered by reacting with sulfuric acid to replace some hydrogen atoms on the aromatic ring with sulfonic acid groups, the resulting functionalized polymer is still considered to have 90% by weight styrene polymeric units.

[0064] As used in this article, inhibitors are molecules that react with vinyl monomer radicals or with radicals on growing vinyl polymer chains to form new radicals that do not participate in vinyl polymerization.

[0065] Macroporous polymer beads possess a porous structure with an average pore size of 20 nm or larger. The pore size is measured using nitrogen gas via the Brunauer-Emmett-Teller (BET) method. Macroporous polymer beads are typically prepared by incorporating a porogen into monomer droplets. The porogen is soluble in the monomer, but insoluble in the polymer; therefore, the phase-separated domains of the porogen are retained as the polymer forms. After polymerization, the porogen is removed by evaporation or by washing with a solvent. The porous structure of the polymer beads consists of the empty spaces left when the porogen is removed from its phase-separated domains.

[0066] The preparation of gel-type polymer beads does not use pore-forming agents. The pores in gel-type polymer beads are the free volumes between atoms in the tangled, possibly cross-linked, polymer chains of the polymer beads. The pores in gel-type polymer beads are less than 20 nm. In some cases, the pores in the gel-type resin are too small to be detected using the BET method.

[0067] If two ions or ionic groups are both anions or both are cations, then the two ions or ionic groups are considered in this document to have “the same” charge, regardless of the magnitude of the charge. For example, the sulfonate ion (i.e., -SO3-) - It is believed to have a similar relationship with carbonate ions (i.e., CO32-). 2- (Identical charges.) Similarly, if one ion or ionic group is an anion and the other is a cation, the two ions or ionic groups are considered in this document to have “opposite” charges, regardless of the magnitude of the charges. (Carboxylic acid groups are considered to include carboxylate anions and hydrogen cations, and sulfonic acid groups are considered to include sulfonate anions and hydrogen cations.)

[0068] As used herein, ion exchange is a method of contacting a solution with an ion exchange resin. Before contact with the solution, the ion exchange resin has functional groups with a certain charge and ions with opposite charges that associate with these functional groups. When the solution is contacted with the ion exchange resin, some ions in the solution attach to the ion exchange resin through ion exchange sites with the same charge that associate with the functional groups on the resin.

[0069] If 5 grams or more of a compound forms a stable solution in 100 ml of water at 25°C, the compound is referred to herein as water-soluble. In the case of some water-soluble polymers, it may be necessary to heat the water above 25°C to dissolve the polymer, but after cooling to 25°C, the solution is stable when maintained at 25°C.

[0070] A suspension is a composition having particles of a substance distributed in a liquid medium. The distributed particles can be liquid or solid; the distributed liquid particles are referred to as droplets. If the medium contains 90% by weight or more water based on the weight of the medium, the medium is "aqueous". The suspension may or may not be stable. That is, the distributed particles may or may not have a tendency to settle to the bottom of the container or float to the top of the container, and may or may not require mechanical agitation to keep the particles distributed in the medium.

[0071] Polymer beads are particles comprising 90% by weight or more of an organic polymer based on the particle weight. Polymer beads are spherical or nearly spherical. A characteristic of polymer beads is their radius. If a bead is not spherical, its radius is referred to herein as the radius of a “reference sphere,” an imaginary sphere having the same volume as the bead. Whether a particle is spherical is assessed by “sphericity,” denoted by the Greek letter Ψ. For a particle having a volume VP and principal axes of lengths a (long), b (medium), and c (short), sphericity is…

[0072]

[0073] As used in this article, the unit of volume is “cubic micrometer” (abbreviated as μm). 3 () refers to the volume of a cube with a side length of 1 micrometer.

[0074] As used in this article, “ambient temperature” is synonymous with “room temperature” and is approximately 23°C.

[0075] An aggregate of particles has a harmonic mean diameter (HMD) as defined below:

[0076]

[0077] Where n is the number of particles, and di is the diameter of the i-th particle.

[0078] The ratios are characterized in this document as follows. For example, if a ratio is considered to be 5:1 or higher, it means that the ratio can be 5:1, 6:1, or 100:1, but not 4:1. To state this characterization in a general way, if a ratio is considered to be X:1 or higher, then the ratio is Y:1, where Y is greater than or equal to X. Similarly, for example, if a ratio is considered to be 2:1 or lower, it means that the ratio can be 2:1, 1:1, or 0.001:1, but not 3:1. To state this characterization in a general way, if a ratio is considered to be Z:1 or lower, then the ratio is W:1, where W is less than or equal to Z.

[0079] The method of the present invention relates to monomer droplets comprising a vinyl monomer and an initiator. The following is a description of the monomer droplets in the presence prior to initiating polymerization.

[0080] Preferably, the amount of monomer in the monomer droplet is 80% by weight or more based on the weight of the droplet; more preferably 90% by weight or more; even more preferably 95% by weight or more.

[0081] Preferred vinyl monomers are styrene monomers, acrylic monomers, and mixtures thereof. Preferably, all monomers used are selected from styrene monomers, acrylic monomers, and mixtures thereof. More preferably, all monomers used are selected from styrene monomers. Vinyl monomers include one or more monofunctional vinyl monomers. Preferred monofunctional vinyl monomers are acrylic and styrene monofunctional monomers; more preferably, monofunctional styrene monomers; even more preferably, styrene. Vinyl monomers also include one or more polyfunctional vinyl monomers. Preferred polyfunctional vinyl monomers are polyfunctional styrene monomers; more preferably, divinylbenzene. Preferably, the amount of vinyl chloride is 0% to 0.1% by weight based on the total weight of all monomers, more preferably 0% to 0.01% by weight; even more preferably 0% by weight.

[0082] Preferably, based on the total weight of all monomers in the droplet, the amount of styrene monomer in the droplet before initiation of polymerization is 50% by weight or higher; more preferably 75% by weight or higher; more preferably 88% by weight or higher; more preferably 94% by weight or higher; more preferably 97% by weight or higher; more preferably 100% by weight.

[0083] Preferably, based on the weight of all monomers in the droplet, the amount of monofunctional vinyl monomer in the droplet before polymerization initiation is 75% by weight or more; more preferably 80% by weight or more; more preferably 85% by weight or more; more preferably 90% by weight or more; more preferably 94% by weight or more. Preferably, based on the weight of all monomers in the droplet, the amount of monofunctional vinyl monomer in the droplet is 99.9% by weight or less; more preferably 99% by weight or less; more preferably 98.5% by weight or less.

[0084] Preferably, based on the weight of all monomers in the droplet, the amount of polyfunctional vinyl monomers in the droplet before initiation of polymerization is 0.1% by weight or more; more preferably 1% by weight or more; even more preferably 1.5% by weight or more. Preferably, based on the weight of all monomers in the droplet, the amount of polyfunctional vinyl monomers in the droplet is less than 25% by weight; more preferably 20% by weight or less; even more preferably 15% by weight or less; even more preferably 10% by weight or less; even more preferably 6% by weight or less.

[0085] Usefully, the amount of multifunctional vinyl monomers in the droplets (“MFMPRIROR”) is characterized as a weight percentage of the total monomers before polymerization is initiated. Preferably, MFMPRIROR is 0.1% or more; more preferably 0.5% or more; more preferably 1% or more; more preferably 1.5% or more; more preferably 2% or more. Preferably, MFMPRIROR is 10% or less; more preferably 8% or less; more preferably 6% or less.

[0086] Another useful aspect is the characterization ratio.

[0087] MFMRATIO=100*MFMPRIOR / MFMTOTAL

[0088] Wherein MFMTOTAL is the total weight percentage of the multifunctional monomers used throughout the polymerization process, including multifunctional monomers present before initiation and those added after initiation. Preferably, MFMTOTAL is 10% or more; more preferably 20% or more; even more preferably 30% or more. Preferably, MFMTOTAL is 80% or less; more preferably 70% or less; even more preferably 60% or less.

[0089] The method of the present invention relates to a suspension of monomeric droplets in an aqueous medium. Preferably, the total amount of monomer is 5% by weight or more, more preferably 10% by weight or more, and even more preferably 15% by weight or more, based on the total weight of the suspension. Preferably, the total amount of monomer is 55% by weight or less, more preferably 35% by weight or less, and even more preferably 30% by weight or less, based on the total weight of the suspension.

[0090] The monomer droplet contains one or more initiators. Preferred initiators have a solubility of 1 gram or less in 100 mL of water at 25°C; more preferably 0.5 grams or less; more preferably 0.2 grams or less; more preferably 0.1 grams or less. Preferred initiators are organic peroxides and hydroperoxides; more preferably peroxide initiators; more preferably benzoyl peroxide and its derivatives; even more preferably benzoyl peroxide. Preferably, the weight ratio of initiator to total monomers is 0.0002:1 or higher; more preferably 0.0005:1 or higher; more preferably 0.001:1 or higher; more preferably 0.002:1 or higher. Preferably, the weight ratio of initiator to total monomers is 0.02:1 or lower; more preferably 0.01:1 or lower; more preferably 0.007:1 or lower.

[0091] The monomeric droplet optionally contains one or more porogens. Preferably, there is very little or no porogen. That is, preferably no porogen, or if present, the amount of porogen is 1% by weight or less based on the weight of the monomeric droplet; more preferably 0.1% by weight or less. More preferably, no porogen is present in the monomeric droplet.

[0092] Monomers normally supplied by manufacturers contain a relatively small amount of inhibitors to prevent accidental polymerization during storage. Common inhibitors are quinones (e.g., 1,4-benzoquinone) and hindered phenols (e.g., 4-tert-butylcatechol, also known as 4-tert-butylcatechol).

[0093] Preferably, prior to initiating polymerization, the monomer droplets either contain no polymer of any kind, or contain a small amount of any kind of polymer. That is, if any polymer is present in the monomer droplets, preferably, the total amount of polymer is 0.1% by weight or less based on the weight of the monomer droplets.

[0094] The aqueous medium preferably comprises one or more water-soluble polymers. Water-soluble polymers are considered to stabilize monomer droplets and prevent aggregation. Suitable water-soluble polymers can be any of a variety of polymer types. Preferred water-soluble polymers are water-soluble polyvinyl alcohol polymers, water-soluble derivatives of cellulose, quaternary ammonium polymers, gelatin, and mixtures thereof. More preferred water-soluble polymers are water-soluble polyvinyl alcohol polymers, water-soluble derivatives of cellulose, and mixtures thereof. Among quaternary ammonium polymers, diallyl dimethyl ammonium chloride (DADMAC) polymers are preferred. Among water-soluble cellulose derivatives, carboxymethyl methyl cellulose is preferred. Among polyvinyl alcohol polymers, those with a degree of hydrolysis of 80% to 90% are preferred. Preferably, the aqueous medium comprises one or more water-soluble polyvinyl alcohol polymers and one or more water-soluble derivatives of cellulose.

[0095] When using one or more water-soluble polymers, preferably, the total amount of the water-soluble polymer is 0.02% by weight or more based on the weight of the aqueous medium; more preferably 0.05% by weight or more; even more preferably 0.1% by weight or more. When using one or more water-soluble polymers, preferably, the total amount of the water-soluble polymer is 2% by weight or less based on the weight of water; more preferably 1% by weight or less; even more preferably 0.5% by weight or less.

[0096] Other methods for stabilizing monomer droplets are also suitable, which can replace one or more water-soluble polymers or other than one or more water-soluble polymers. For example, solid particles smaller than the monomer droplets can remain on the surface of the droplets and stabilize them. An example of such solid particles is colloidal silica particles.

[0097] The aqueous suspension of the monomeric droplets optionally contains one or more suspending agents. Suspension agents are considered to stabilize the monomeric droplets. Suspension agents can be introduced by adding them to the aqueous phase, by adding them to the monomeric droplets, or by a combination thereof. Regardless of how the suspending agent is introduced, the preferred amount of suspending agent is from 0.001% to 0.1% by weight, based on the weight of the monomeric droplets. A preferred suspending agent is 4-vinylphenylboronic acid.

[0098] The nature of the polymerization initiation step depends in part on the nature of the initiator used. For example, when a thermal initiator is used, the initiation conditions involve establishing a temperature above 25°C, which is high enough to decompose most of the initiator molecules to form free radicals. In another example, if a photoinitiator is used, the initiation conditions involve exposing the initiator to radiation of sufficiently low wavelength and sufficiently high intensity to decompose most of the initiator molecules to form free radicals. In yet another example, when the initiator is a redox initiator, the initiation conditions involve the presence of sufficiently high concentrations of both the oxidant and the reductant, resulting in a significant number of free radicals. Preferably, a thermal initiator is used. Preferably, the initiation conditions involve a temperature of 55°C or higher, more preferably 70°C or higher. That is, the suspension is preferably provided at a temperature below 40°C, and the initiator present at said temperature does not produce a significant number of free radicals. Then, preferably, step (b) involves raising the temperature to the initiation conditions.

[0099] Following step (b), at any given time, the extent of free radical polymerization in the container containing the suspension can be characterized as follows, while polymerization is occurring.

[0100] Level = 100 * PM / TM

[0101] Where PM is the mass of the polymer formed by the free radical polymerization process, and TM is the total mass of monomers added to the container up to that point (including the initial monomer droplets and monomers added during the polymerization process).

[0102] Prior to the start of the polymerization process, droplets are present in the suspension, and said droplets contain vinyl monomers and an initiator. Preferably, the droplets are distributed throughout the aqueous medium. Preferably, the composition of the aqueous medium contains water in an amount of 90% by weight or more; more preferably 95% by weight or more; more preferably 97% by weight or more. The compound dissolved in the water is considered part of a continuous liquid medium. Preferably, the volume average particle size of the droplets is from 50 μm to 1,500 μm.

[0103] In the method of this invention, a feed solution is added to the suspension once polymerization has begun in the monomer droplets. The act of adding the monomer to the suspension after polymerization has begun is referred to herein as “gradual addition” or GA. The feed solution can be added at any rate. The rate of feed solution addition can be constant, or sometimes faster than at other times. The feed solution can be added in one continuous addition (which can be rapid or slow), or the addition of the feed solution can be interrupted once or multiple times.

[0104] When the degree of reaction reaches the point marked "EXTSTART" herein, the feed solution is added. EXTSTART ranges from 0% to 50%, including the endpoints. Preferably, EXTSTART is 40% or less; more preferably 30% or less; more preferably 20% or less; even more preferably 10% or less.

[0105] The degree of reaction, "EXTSTOP," refers to the degree of reaction after the final feed solution is added to the suspension. No further feed solution is added to the suspension after EXTSTOP. EXTSTOP ranges from 5% to 100%. Preferably, EXTSTOP is 85% or less. Preferably, the amount...

[0106] EXTDIFF = EXTSTOP - EXTSTART

[0107] The percentage is 5% or higher; more preferably 20% or higher; more preferably 50% or higher; more preferably 60% or higher.

[0108] Preferably, the feed solution contains all types of total vinyl monomers in an amount of 75% by weight or more based on the weight of the feed solution; more preferably 85% by weight or more; more preferably 95% by weight or more; more preferably 99% by weight or more.

[0109] Preferably, the amount of the polyfunctional monomer in the feed solution is 30% by weight or more based on the weight of the feed solution; preferably 40% by weight or more; more preferably 45% by weight or more; more preferably 50% by weight or more; more preferably 55% by weight or more; more preferably 60% by weight or more. When the polyfunctional monomer is divinylbenzene (DVB), industrial-grade DVB is suitable, which is a mixture containing about 63% by weight of chemically pure DVB and about 37% by weight of ethylvinylbenzene (EVB), and less than 1% by weight of other impurities in total. When the composition is stated herein to contain a certain amount of DVB, it is assumed that the composition contains EVB in addition to the specified amount of DVB, and the EVB:DVB weight ratio is about 37:63. When using such industrial-grade DVB, the amount of industrial-grade DVB in the feed solution is preferably 50% by weight or more based on the weight of the feed solution; more preferably 60% by weight or more; more preferably 70% by weight or more; more preferably 80% by weight or more; more preferably 90% by weight or more; more preferably 95% by weight or more.

[0110] Preferably, the feed solution either does not contain an initiator, or contains an initiator in an amount of 100 ppm or less by weight; more preferably 10 ppm or less; even more preferably 1 ppm or less.

[0111] Preferably, the feed solution either contains no water or contains water in an amount of 20% by weight or less based on the weight of the feed solution; more preferably 10% by weight or less; more preferably 3% by weight or less; more preferably 1% by weight or less; more preferably 0.3% by weight or less; more preferably 0.1% by weight or less.

[0112] Examples (“dispersion feed” examples) are also envisioned, wherein the feed solution is replaced by a feed composition, which is a dispersion of monomer droplets in an aqueous medium. Such dispersions can be of any type, including, for example, suspensions, emulsions, microemulsions, or nanoemulsions. Such dispersions optionally contain one or more water-soluble polymers as described above, one or more surfactants, one or more dispersants, or mixtures thereof. In the dispersion feed examples, emulsions are preferred. Among emulsions, emulsions containing one or more anionic surfactants are preferred.

[0113] In the dispersion feed examples, the total amount of monomers in the monomer composition is 5% by weight or more based on the weight of the feed composition; more preferably 10% by weight or more; more preferably 20% by weight or more; more preferably 40% by weight or more. In the dispersion feed examples, the total amount of monomers in the monomer composition is 60% by weight or less based on the weight of the feed composition; more preferably 55% by weight or less.

[0114] In the dispersion feed examples, it is useful to characterize the amount of the polyfunctional vinyl monomer as a weight percentage of the monomer content in the feed composition. In the dispersion examples, preferably, the amount of the polyfunctional vinyl monomer is 50% to 100% by weight based on the total weight of the monomers in the feed composition; more preferably 75% to 100% by weight; more preferably 90% to 100% by weight; and even more preferably 95% to 100% by weight.

[0115] In the dispersion feed examples, the suitable and preferred conditions (degree of reaction, etc.) for feeding during polymerization are the same as those described above.

[0116] The present invention also relates to polymer bead assemblies. The polymer bead assemblies are preferably prepared by the method of the present invention. The polymer beads comprise a polymer. The polymer beads are particles that are solid at 25°C and contain a polymer in an amount of 90% by weight or more, more preferably 95% by weight or more, based on the weight of the polymer particles.

[0117] The polymer beads can be macroporous beads or gel beads. Gel beads are preferred.

[0118] Preferably, the volume average particle size of the polymer beads is 50 μm or greater; more preferably 100 μm or greater; even more preferably 200 μm or greater; even more preferably 400 μm or greater. Preferably, the volume average particle size of the polymer beads is 1,500 μm or less; even more preferably 1,000 μm or less.

[0119] The preferred polymer in the polymer particles is a polymer formed by free radical polymerization of the aforementioned preferred vinyl monomers. Preferably, the polymer contains polymeric units of styrene monomers in an amount of 5% by weight or more, more preferably 25% by weight or more, more preferably 50% by weight or more, more preferably 75% by weight or more, and more preferably 95% by weight or more, based on the polymer weight. Preferably, the type of monomers used as polymeric units in the polymer is the same as those preferably used in the polymerization process described above.

[0120] The preferred polymer has polymeric units of polyfunctional vinyl monomers in an amount of 1% or more based on the polymer weight; more preferably 1.5% or more; more preferably 2% or more. The preferred polymer has polymeric units of polyfunctional vinyl monomers in an amount of 25% or less based on the polymer weight; more preferably 20% or less; more preferably 15% or less; more preferably 11% or less; more preferably 6% or less.

[0121] The preferred polymer has a polymeric unit comprising a monofunctional vinyl monomer, wherein the amount is 99.7% by weight or less, more preferably 99.5% by weight or less, more preferably 99% by weight or less, and more preferably 98.5% by weight or less, based on the polymer weight. The preferred polymer has a polymeric unit comprising a monofunctional vinyl monomer, wherein the amount is 75% by weight or more, more preferably 80% by weight or more, more preferably 85% by weight or more, more preferably 90% by weight or more, and more preferably 94% by weight or more, based on the polymer weight.

[0122] The polymer beads contain a relatively uniform distribution of polymeric units of polyfunctional vinyl monomers. The uniformity of the distribution of polymeric units of polyfunctional vinyl monomers can be characterized as follows.

[0123] MVAV = Average concentration of polyfunctional vinyl monomer polymerization units within a single bead (in moles per cubic micrometer).

[0124] T1000 = a sequence of 1,000 connected polymeric monomer units.

[0125] MVSEQ = For a specific T1000, the weight percentage of the polymeric unit of the multifunctional vinyl monomer based on the weight of T1000.

[0126] MVRATIO = MVSEQ / MVAV

[0127] When selecting T1000, any polymeric unit can be chosen as the first unit of the sequence. Then, any polymeric unit covalently bonded to the first polymeric unit can be chosen as the second unit in the sequence. Similarly, each selected unit is covalently bonded to the preceding unit in the sequence. No polymeric unit can appear twice in a T1000 sequence. The T1000 sequence is complete when 1000 polymeric units have been selected. Another way to describe the process of selecting T1000 is to state that a first polymeric unit is picked up, and then a path is traced along the covalently bonded polymeric units until the path is 1000 units long. Paths are selected such that they do not intersect themselves. Each bead contains many T1000 sequences. The T1000 sequences do not undergo physical changes or are not removed from the beads. The T1000 sequence is a tool for characterizing the degree of uniformity of the polymer beads.

[0128] A bead is considered "uniform" if it has a relatively uniform distribution of polymeric units of polyfunctional vinyl monomers. That is, a bead is considered uniform if 90% or more of all T1000 sequences in the bead have an MVRATIO of 1.5 or less. Preferred beads have a high degree of uniformity such that 90% or more of all T1000 sequences in the bead have an MVRATIO of 1.25 or less.

[0129] In the bead assembly of the present invention, most of the beads are uniform. That is, the amount of uniform beads is 90% by volume or higher; more preferably 95% by volume or higher; more preferably 99% by volume or higher. More preferably, the amount of beads in which 90% or more of all T1000 sequences have an MVRATIO of 1.25 or less is 90% by volume or higher; more preferably 95% by volume or higher; more preferably 99% by volume or higher.

[0130] It is useful to consider the percentage of T1000 sequences with an MVRATIO of 0.5 or less per sequence number. Preferably, 35% or less of the T1000 sequences per sequence number will have an MVRATIO of 0.5 or less. More preferably, 25% or less of the T1000 sequences per sequence number will have an MVRATIO of 0.5 or less.

[0131] The average sphericity of the polymer beads is preferably 0.8 or higher; more preferably 0.85 or higher; more preferably 0.9 or higher; and even more preferably 0.95 or higher.

[0132] The preferred use of the polymer produced during the free radical polymerization process of this invention is in the conversion process for producing ion exchange resins. Ion exchange resins are classified into the following categories: Weak base anion exchange resins have primary, secondary, or tertiary side amino groups. Strong base anion exchange resins have side quaternary ammonium groups. Weak acid cation exchange resins have side carboxylic acid groups. Strong acid cation exchange resins have side sulfonic acid groups. When any of these side functional groups has been attached to a polymer bead, the bead is called a "functionalized resin".

[0133] Typically, in the preparation of weakly basic anion exchange resins from polymer beads (such as cross-linked polystyrene beads), the beads are advantageously halogenated, preferably halogenated, and most preferably chloromethylated, and then ion-active exchange groups are attached to the halogenated copolymer. The halogenation reaction typically consists of the following steps: swelling the cross-linked addition copolymer with a halogenating agent (preferably bromomethyl methyl ether, chloromethyl methyl ether, or a mixture of formaldehyde and hydrochloric acid, most preferably chloromethyl methyl ether), and then reacting the copolymer with the halogenating agent in the presence of a Friedel-Crafts catalyst (such as zinc chloride, ferric chloride, or aluminum chloride). Weakly basic anion exchange resins are typically prepared by reacting the halogenated copolymer with ammonia, a primary amine, or a secondary amine. Strongly basic anion exchange resins are typically prepared by reacting the halogenated copolymer with a tertiary amine.

[0134] Typically, in the preparation of strong acid cation exchange resins from polymer beads (such as cross-linked polystyrene beads), the beads are advantageously sulfonated. Usually, a suitable swelling agent is used to swell the beads, and the swollen beads are reacted with a sulfonating agent (such as sulfuric acid or chlorosulfonic acid or sulfur trioxide or mixtures thereof).

[0135] In addition to the polymer beads themselves, the aggregates of functionalized polymer beads typically also contain water. Normally, methods for preparing functionalized polymer beads involve contact between the functionalized polymer beads and water, and the removal of excess liquid water; however, a significant amount of water remains as part of the functionalized polymer bead aggregate. It is expected that water will be adsorbed into the functionalized polymer beads. Based on the weight of the functionalized polymer bead aggregate, the amount of water is typically 30% to 90% by weight.

[0136] The polymer beads of the present invention are envisioned for a variety of purposes. The functionalized polymer beads will be used in many purposes where ion exchange resins are useful. For example, the increased crushing strength and permeability of the functionalized polymer beads of the present invention are expected to make these beads suitable for use as water purification resins or catalysts in preferred applications. When the functionalized polymer beads of the present invention are used as catalysts, they are expected to increase the reaction rate of the catalyzed reaction. The uniform spatial distribution of the polyfunctional vinyl monomer polymerization units in the functionalized polymer beads of the present invention is expected to have the effect that more sites available for catalysis on the beads will also result in an optimal concentration of polyfunctional monomer polymerization units compared to previously known beads, leading to an optimal reaction rate.

[0137] A preferred method of using the polymer beads of the present invention involves passing a liquid through a bed of polymer beads. Specifically, an assembly of polymer beads is placed in a container that traps the polymer beads in place, the container having an inlet for liquid entry and an outlet for liquid exit, the inlet allowing the liquid to flow through the container while maintaining close contact with the polymer beads.

[0138] When the intended use is water purification, a functionalized resin is used to remove unwanted ions from water. The resin has a functional group (referred to herein as "functional group (iii)"). The resin is selected such that functional group (iii) has a charge opposite to that on the unwanted ion. Prior to purification, functional group (iii) associates with a counterion (referred herein as "ion (iv)") that does not bind to the resin. Ion (iv) has the same charge as the unwanted ion. Preferably, the proportion of functional group (iii) associated with ion (iv) is 50 mol% or higher; more preferably 75 mol% or more; even more preferably 92 mol% or more.

[0139] In the “loading” step, the water to be purified is passed through a resin bed, and unwanted ions in the water are loaded onto the functionalized polymer beads by associating with functional group (iii) to exchange ions (iv). Ultimately, the resin is loaded at or near its capacity to retain unwanted ions. Then, to remove the unwanted resin, the functionalized polymer beads undergo a “regeneration” step, in which a regeneration solution is passed through the resin bed. The regeneration solution contains dissolved ions, including ions (v) of the same class as ion (iv). Ions (v) replace the unwanted ions on the resin, and these unwanted ions are removed along with the regeneration solution.

[0140] Preferably, the loading and regeneration cycle is repeated. That is, a new batch of water containing the same unwanted ions is passed through the resin bed to load the resin with the unwanted ions, and then the resin is regenerated as described above. Preferably, the loading and regeneration process is repeated 10 times or more; more preferably 20 times or more.

[0141] Repeated loading and regeneration cycles result in osmotic shock to the functionalized polymer beads because the equilibrium water content (and therefore bead size) is a function of specific counterions. Repeated cycles can cause some or all of the polymer beads to break down. Preferably, the polymer beads of the present invention minimize such breakage.

[0142] The above discussion envisions a single undesirable ion with a certain charge. If the water also contains a second undesirable ion with a charge opposite to that of the first undesirable ion, it is envisioned that the water could be brought into contact with a second resin having functional groups with a charge opposite to that of the functional groups on the first resin. The two resins can be used sequentially or can be mixed together.

[0143] For example, polymer beads functionalized with sulfonic acid groups are strong acid cation exchange resins (“SAC”). SAC can be used to remove unwanted sodium ions from water. Initially, SAC can be in hydrogen form. That is, more than half (on a molar basis) of the sulfonic acid groups have the counterion H+. + Then, an aqueous NaCl solution is passed through a bed of SAC to exchange hydrogen ions for sodium ions, so that sodium ions are retained on the SAC during a process known as “loading” the resin, making the resin in its sodium form. Eventually, the SAC reaches or approaches the limit of its ability to retain sodium ions. The SAC can then be regenerated, for example, by passing an aqueous solution of H₂SO₄ through the SAC bed, to bring the resin back to its hydrogen form. This cycle of loading followed by regeneration puts the resin beads under osmotic pressure because the sodium and hydrogen forms have different equilibrium water contents, and the osmotic shock of repeated cycles tends to break some beads.

[0144] For another example, polymer beads functionalized with quaternary ammonium groups are strong base anion exchange resins (“SBA”). SBA can be used to remove unwanted chloride ions from water. Initially, SBA can be in hydroxide form. That is, more than half (on a molar basis) of the quaternary ammonium groups have anti-counterionic ions (OH-). - The NaCl aqueous solution is then passed through the bed of SBA to exchange hydroxide ions for chloride ions, so that chloride ions are retained on the SBA during a process known as "loading" the resin. Finally, the SBA reaches or approaches its limit of chloride ion retention. The SBA can then be regenerated, for example, by passing an aqueous NaOH solution through the SBA bed, to return the resin to its hydroxide form. This cycle of loading followed by regeneration keeps the resin beads under osmotic pressure because the chloride and hydroxide forms have different equilibrium water contents, and the osmotic shock from repeated cycles tends to break some beads.

[0145] Similar loading and regeneration processes can be performed with these or other resins to remove these or other ions. Weak acid cation exchange resins or strong acid cation exchange resins can be used to remove monovalent or polyvalent cations. Weak basic anion exchange resins or strong basic cation exchange resins can be used to remove unwanted monovalent and / or polyvalent anions. Any of these processes involving loading and regeneration cycles generates permeation stress on the resin beads.

[0146] When the intended use is water purification, the crush resistance and resistance to permeation shock make the resin of this invention advantageous. Because the beads have a low tendency to break, a given bead assembly will have a long service life before the beads need to be replaced. Furthermore, when beads break, fragments fill the gaps between the beads, hindering water flow through the bead bed and causing an increase in pressure drop from the inlet to the outlet of the bed. In addition, broken beads can cause channeling, reducing the amount of water the bead bed can handle, thus necessitating more frequent bead regeneration, which in turn increases chemical costs and permeation stress on the beads.

[0147] When the intended use of the resin is as a catalyst, a functionalized aggregate of polymer beads (referred to herein as "resin") is employed by contacting the resin with one or more reactants and allowing a chemical reaction involving one or more reactants to occur, in order to produce one or more products. In a preferred embodiment of the catalyst, the aggregate of polymer beads is functionalized with sulfonic acid groups to produce SAC. When used as a catalyst, SAC is referred to as an "acid catalyst".

[0148] Resins intended to be used as catalysts are characterized by their moisture retention capacity (MHC). MHC is the amount of water present in a polymer bead assembly when a large amount of liquid water has been separated from the beads and the beads have been allowed to equilibrate with air having 100% relative humidity. Preferably, the MHC of the resin intended to be used as a catalyst is 90% by weight or less based on the total weight of the resin bead assembly including the beads and water; more preferably 80% by weight or less. Preferably, the amount of water present in the resin prior to contact with acetone and phenol is 50% by weight or more based on the weight of the resin; more preferably 60% by weight or more.

[0149] Preferred reactants are acetone and phenol, which react to prepare 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A). It is anticipated that two moles of phenol react with one mole of acetone to prepare one mole of bisphenol A and one mole of water. In the formation of bisphenol A, a preferred resin catalyst is SAC resin. The resin may or may not react with an accelerator before contact with acetone and phenol. In a preferred embodiment, the resin is reacted with an accelerator before contact with acetone and phenol. Preferred accelerators have both amino and thiol groups. Preferably, the amino groups on the accelerator are linked to sulfonic acid groups on the resin. Preferably, the molar percentage of sulfonic acid groups linked to the amino groups of the accelerator is 5% to 50%. Preferably, water is removed from the polymer bead assembly, for example, by rinsing with phenol, before contact with acetone and phenol. Preferably, immediately before contact with acetone and phenol, the water content in the polymer bead assembly is 2% by weight or less based on the polymer bead assembly; more preferably 1% by weight or less.

[0150] Preferably, when the resin is in contact with phenol and acetone, the resin is at a temperature of 55°C or higher; more preferably, at a temperature of 60°C or higher.

[0151] Crushing resistance is also an advantage when the intended application is catalysis. The resin of the present invention will have a longer lifespan, and the reduced level of fine particles will allow reactants to pass through the resin bed with a lower pressure drop.

[0152] The following are examples of the present invention.

[0153] Use the following terms, abbreviations, and materials:

[0154] Jetted = Using the jetting procedures described in US 4,444,960 and US 4,623,706, monomer droplets are introduced into an aqueous medium.

[0155] tBC = 4-tert-butylcatechol; some tBC exists at the DVB level used.

[0156] DVB stands for divinylbenzene, manufactured and supplied by Dow Chemical Company. The DVB grade used is a mixture containing 63% by weight of pure divinylbenzene and approximately 37% by weight of ethylvinylbenzene. The percentages of DVB listed below refer to the amount of pure DVB. When DVB is present, it is assumed that EVB is also present in an EVB:DVB weight ratio of approximately 37:63. DVB contains approximately 1000 ppm of tBC by weight.

[0157] tBC-free DVB = DVB that does not contain tBC. To prepare tBC-free DVB, tBC is extracted from the DVB fraction indicated by a series of batch washings with 4% NaOH.

[0158] CMMC = Carboxymethyl methyl cellulose, produced and supplied by Dow Chemical Company.

[0159] PVOH = SELVOL TM 523 Polyvinyl alcohol, from Sekisui Specialty Chemicals.

[0160] HEMC = WALOCEL TM MKX 15000PF 01 Hydroxyethyl Cellulose, from Dow Chemical Company

[0161] SBA = Strong base anion exchange resin; styrene / DVB copolymer functionalized with quaternary ammonium groups.

[0162] SAC = Strong acid cation exchange resin; styrene / DVB copolymer functionalized with sulfonic acid groups.

[0163] Tris = Tris(hydroxymethyl)aminomethane, 100% solid, supplied by Fisher Scientific, for use as a 20% by weight aqueous solution.

[0164] PADMAC = 20% by weight of an aqueous solution of poly(diallyldimethylammonium chloride), also known as poly(DADMAC).

[0165] Gelatin = animal-based gelatin, with an isoelectric point of approximately 8.5.

[0166] VPBA = 4-vinylphenylboronic acid

[0167] BPO = Benzoyl peroxide, 75% by weight purity

[0168] DI water = deionized water

[0169] Dichromate: = Sodium dichromate dihydrate solution, concentration = 70% by weight aqueous solution of dihydrate.

[0170] GA = Gradually Add

[0171] Ambient temperature = approximately 23℃

[0172] Eight suspension polymerization protocols were used, labeled A, B, D, E, F, G, and H. These protocols are distinguished by the following protocol. After forming the copolymer beads, they were functionalized using the methods listed in the last column. Details of the functionalization methods are shown in the table below.

[0173] <![CDATA[ polymer (1) ]]> <![CDATA[ Inhibitors (2) ]]> <![CDATA[ form (3) ]]> <![CDATA[ Total DVB (4) ]]> <![CDATA[ Functionalization ]]> A CMMC+PVOH <![CDATA[NaNO2]]> injection 4.65％ sulfonation B CMMC+PVOH <![CDATA[NaNO2]]> injection 5.2％ sulfonation C CMMC+PVOH <![CDATA[NaNO2]]> injection 4.65% to 5.2% sulfonation D CMMC+PVOH <![CDATA[NaNO2]]> injection 2.0% to 2.8% sulfonation E PADMAC + Gelatin <![CDATA[NaNO2]]> injection 4.65％ sulfonation F CMMC+PVOH <![CDATA[NaNO2]]> injection 9.2% to 11.0% sulfonation G HEMC dichromate agitation 7.6% to 9.0% sulfonation H PADMC + Gelatin <![CDATA[NaNO2]]> injection 4.65％ CM / A

[0174] 1. Water-soluble polymers in aqueous media

[0175] 2. Inhibitors in aqueous media

[0176] 3. Whether droplets are formed by spraying or agitation.

[0177] 4. The total weight percentage of DVB throughout the process, expressed as a percentage of the total individual unit weight.

[0178] When preparing the droplet mixtures or aqueous media described below, some portions of the mixture are sometimes heated to above 25°C to achieve good mixing. However, when the droplets form and suspend in the aqueous medium, all components are at ambient temperature.

[0179] When the copolymer is converted into SAC resin, the copolymer-containing polymer beads are sulfonated with sulfuric acid using a standard sulfonation method to achieve a degree of substitution such that at least 95 mol% of the aromatic rings on the polymer units of the monofunctional vinyl monomers have sulfonate groups.

[0180] Crushing strength was measured as follows. Functionalized polymer beads were exposed to air at 100% humidity and 50°C for 4 days. The beads were then covered with deionized water and stored at room temperature (approximately 23°C) for one hour or longer. Individual beads were placed on a plate of a compression tester at room temperature, with a drop of water covering the bead. The plates were pressed together at 6.0 mm / min until the particles broke, and the peak force was recorded. The procedure was repeated for at least 30 beads, and the average peak force was reported as “crushing strength”. The testing apparatus was a TCD 200 Chatilon with a medium-low speed motor (2.5 to 63.5 mm / min). TM Force testing instrument. The force gauge is a DFGS10 model. Crushing strength is reported in grams per bead (g / bd).

[0181] Permeability stability (OS) was measured as follows. Functionalized polymer beads were conditioned by contacting an aqueous NaCl solution at ambient temperature (approximately 23°C). The NaCl solution was decanted, and the wet resin was passed through a sieve to produce resin samples with diameters ranging from 500 μm to 710 μm. The resin was then placed in a vertical, straight-walled glass column. A single cycle was performed as follows: fluid was drained from the column by gravity; the resin in the column was brought into contact with solution #1; the column was backwashed with water; fluid was drained from the column by gravity; the resin in the column was brought into contact with solution #2; fluid was drained from the column, and the column was backwashed with water. The test was repeated for 50 cycles. Solution #1 was an aqueous H₂SO₄ solution. Solution #2 was an aqueous NaOH solution. Cycles of exposure to different solutions resulted in some particle breakage. After the exposure cycle, the beads were placed on a sieve through which objects with a diameter less than 500 μm passed. Material retained on the sieve was considered a whole bead, and material passing through the sieve was considered fragments of broken beads. The permeability stability was...

[0182] OS(%) = 100X W 碎片 / (W 完整 +W 碎片 )

[0183] Among them W 碎片 = The weight of the fragment, and W 完整 =Weight of the complete bead. A lower OS value is more desirable.

[0184] The storage stability of the functionalized resin samples was tested as follows. The resin was separated from a large volume of water and equilibrated with air at ambient temperature and 100% relative humidity. The resin was then placed in a sealed vial and stored at ambient temperature for 30 days. The resin was then thoroughly mixed with DI water at a weight ratio of 3 parts water to 1 part resin. Water was removed by filtration, and the conductivity and absorbance of the water at 350 nm were tested using standard instruments.

[0185] In all schemes except G, the weight ratio of droplet component to aqueous phase component is 0.61:1. In scheme G, the weight ratio of droplet component to aqueous phase component is 1:1. DVB is added gradually during polymerization, continuously within the range shown in the table below for example R1. Although the addition of DVB is continuous, the rate of addition varies during the process.

[0186] The composition of the starting droplets in the following examples (immediately before polymerization initiation) is as follows. Amounts are based on weight % of the monomer droplet weight. (All samples with the same prefix use the same aqueous medium composition. For example, examples A-2a(1), A-2A(2), and A-2b all use the same aqueous medium composition and are labeled “A-2”). The total weight of each monomer droplet composition is 100%. Samples with the suffix “Comp” are used in the comparative method. BPO is present as an initiator in all starting droplets.

[0187] <![CDATA[ Example ]]> <![CDATA[ DVB ]]> <![CDATA[ Stabilizers ]]> <![CDATA[ DVB without t-BC ]]> <![CDATA[ styrene ]]> A-1Comp 4.65 VPBA 0 margin A-2a 2.0 VPBA 0 margin A-2b 2.0 VPBA 0 margin A-2c 0.8 VPBA 0 margin B-1Comp 2.25 none 2.95 margin B-2 2.25 none 0 margin C-1Comp 4.65 none 0 margin C-2 2.25 none 0 margin D-1Comp 2.0 VPBA 0 margin D-2a 0.8 none 0 margin D-2b 1.1 none 0 margin

[0188] <![CDATA[ Example ]]> <![CDATA[ DVB ]]> <![CDATA[ Stabilizers ]]> <![CDATA[ styrene ]]> E-1 4.65 none margin E-2 2.0 none margin F-1 9.2 VPBA margin F-2 4.65 none margin G-1 7.6 none margin G-2 3.9 none margin

[0189] The aqueous media compositions in the following examples are as follows. Amounts are weight percent based on the weight of the aqueous media. In all cases, the aqueous phase concentration of the stabilizer results in a percentage of beads with a sphericity of 0.8 or higher that is at least 99% of the total number of beads. In all cases, the aqueous or monomeric phase concentration of the stabilizer results in a percentage of beads with a sphericity of 0.8 or higher that is at least 99% of the total number of beads. In all cases, the aqueous phase concentration of the latex inhibitor results in a weight percentage of the emulsion polymer at the end of the reaction that is less than 0.5% of the total weight of the polymer beads.

[0190] The harmonic average diameter of the final polymer beads formed by jetting is 430-470 micrometers. For droplets formed by agitation, the harmonic average diameter of the final polymer beads is 490-650 micrometers.

[0191] <![CDATA[ Example ]]> <![CDATA[ stabilizer ]]> <![CDATA[ Latex inhibitors ]]> <![CDATA[ Stabilizers ]]> A-1Comp CMMC+PVOH <![CDATA[NaNO2]]> none A-2 CMMC+PVOH <![CDATA[NaNO2]]> none B-1Comp CMMC+PVOH <![CDATA[NaNO2]]> VPBA B-2 CMMC+PVOH <![CDATA[NaNO2]]> VPBA C-1Comp CMMC+PVOH <![CDATA[NaNO2]]> VPBA C-2 CMMC+PVOH <![CDATA[NaNO2]]> VPBA D-1Comp CMMC+PVOH <![CDATA[NaNO2]]> none D-2 CMMC+PVOH <![CDATA[NaNO2]]> VPBA

[0192] <![CDATA[ Example ]]> <![CDATA[ stabilizer ]]> <![CDATA[ Latex inhibitors ]]> E-1Comp Gelatin + PADMAC <![CDATA[ NaNO2 ]]> E-2 Gelatin + PADMAC <![CDATA[ NaNO2 ]]>

[0193] <![CDATA[ Example ]]> <![CDATA[ stabilizer ]]> <![CDATA[ Latex inhibitors ]]> <![CDATA[ Stabilizers ]]> F-1Comp CMMC+PVOH <![CDATA[ NaNO2 ]]> none F-2 CMMC+PVOH <![CDATA[ NaNO2 ]]> VPBA G-1Comp HEMC dichromate none G-2 HEMC dichromate none

[0194] Comparative example A1-Comp (no monomers added after polymerization initiation) using scheme A.

[0195] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion rate of 80%–85% within 330–390 minutes. Once the conversion to the polymer was in the 80%–85% range, the pH was adjusted by adding Tris to the reactor—ensuring a final pH in the range of 8–9. The reaction system was heated to 97°C. After 1 hour at 97°C, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature. Two identical polymerizations were then carried out.

[0196] Also use instances A-2a and A-2b of scheme A.

[0197] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 390–550 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the feed rate of DVB varied over time. Two repeated polymerizations of A-2a were carried out, labeled A-2a(1) and A-2a(2).

[0198] Once the conversion to the polymer is in the range of 60%-75%, Tris is added to the reactor to bring the final pH to the range of 8-9. The reaction system is heated to 97°C within 60 minutes of Tris addition. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0199] Also use instance A-2c of scheme A.

[0200] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 390–550 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table of Example R1 below, where the DVB feed rate varied over time.

[0201] Once the conversion to the polymer is in the range of 60%-75%, Tris is added to the reactor to bring the final pH to the range of 8-9. The reaction system is heated to 97°C within 60 minutes of Tris addition. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0202] Comparative example B1-Comp (no monomers added after polymerization initiation) using scheme B.

[0203] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion rate of 80%–85% within 480–560 minutes. Once the reaction temperature was reached, a feed of 0.1% tBC in water was introduced into the reactor. The tBC feed rate was varied over time to simulate a normal tBC feed accompanied by DVB.

[0204] tBC was gradually added from 0% to 57%. Prior to polymerization initiation, the tBC concentration in the monomer droplets was 0.0055% by weight. At the end of the tBC feed, the tBC concentration in the monomer droplets (partially or completely converted to polymer) was 0.0101% by weight.

[0205] Once the conversion to the polymer is in the range of 80%-85%, the pH is adjusted by adding Tris to the reactor to bring the final pH to the range of 8-9. The reaction system is then heated to 97°C. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0206] Instances B-2a, B-2b, B-2c, B-2d, B-2e, and B-2f of scheme B are also used.

[0207] Replicas of B-2b were prepared and labeled as B-2b(1) and B-2b(2).

[0208] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 420–600 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the DVB feed rate varied over time.

[0209] Once the conversion to the polymer is in the range of 60%-85%, Tris is added to the reactor to bring the final pH to the range of 8-9. The reaction system is heated to 97°C within 60 minutes of Tris addition. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0210] Comparative example using scheme C: C1-Comp (no monomer added after polymerization initiation).

[0211] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion of 80%–85% within 330–390 minutes. Once the reaction temperature was reached, Tris was added to the reactor to bring the final aqueous pH to the range of 8–9. Once the conversion was in the 80%–85% range, the system was heated to 97°C. After 1 hour at 97°C, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0212] Example C-2 using scheme C

[0213] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 420–600 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the DVB feed rate varied over time.

[0214] Once the conversion rate is in the range of 60%-85%, Tris is added to the reactor to bring the final pH to the range of 8-9. The reaction system is heated to 97°C within 60 minutes of Tris addition. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0215] Comparative example using scheme D: D1-Comp (no monomers added after polymerization initiation).

[0216] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion of 80%–85% within 420–600 minutes. Once the conversion to the polymer was in the 80%–85% range, the pH was adjusted by adding Tris to the reactor—ensuring a final pH in the range of 8–9. The reaction system was heated to 97°C. After 1 hour, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature. Two identical polymerizations were then carried out.

[0217] Example D-2a using scheme D.

[0218] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 390–550 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the feed rate of DVB varied over time. Two repeated polymerizations were performed, labeled D-2a(1) and D-2a(2).

[0219] Once the conversion to the polymer is in the range of 20%-30%, a Tris buffer is added to the reactor to bring the final pH to 8-9. When the conversion reaches 80%-85%, additional Tris buffer is added to bring the final pH to 8-9. The reaction system is then heated to 97°C within 60 minutes of adding Tris. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0220] Use instance D-2b of scheme D. Use the same scheme as in D-2a, except that DVB is gradually added within the extent range shown in the table of instance R1 below. Perform two repeated aggregations, labeled D 2b(1) and D-2b(2).

[0221] Comparative example using scheme E: E-1Comp (no monomer added after polymerization initiation).

[0222] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion of 80%–85% within 210–270 minutes. Once the conversion to the polymer was in the 80%–85% range, the reaction system was heated to 92°C. After 1 hour, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0223] Example E-2 using scheme E.

[0224] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 300–360 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the DVB feed rate varied over time.

[0225] Once the conversion to the polymer is in the range of 80%-85%, the reaction system is heated to 92°C. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0226] Comparative example F1-Comp (no monomer added after polymerization initiation) using scheme F.

[0227] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion of 80%–85% within 300–360 minutes. Once the conversion to the polymer was in the 80%–85% range, the pH was adjusted by adding Tris to the reactor—ensuring a final pH in the range of 8–9. The reaction system was heated to 97°C. After 1 hour, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0228] Example F-2 using scheme F.

[0229] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 330–390 minutes. Once the reaction temperature was reached, tBC-free DVB was fed into the reactor to the extent shown in the table below for Example R1, where the DVB feed rate varied over time.

[0230] Once the conversion to the polymer is in the range of 80%-85%, Tris is added to the reactor to bring the final pH to the range of 8-9. The reaction system is heated to 97°C within 60 minutes of Tris addition. After 1 hour, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0231] A comparative example of scheme G is G1-Comp (no monomers are added after polymerization initiation).

[0232] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to achieve a conversion rate of 80%–85% within 300–360 minutes. Once the polymer conversion was in the 80%–85% range, the reaction system was heated to 90°C. After 3 hours, the system was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0233] Example G-2 using scheme G

[0234] The reaction mixture was subjected to aqueous suspension polymerization as follows. A combination of reaction temperature and BPO concentration was selected to result in a conversion of 80%–85% over 420–600 minutes. Once the reaction temperature was reached, DVB was fed into the reactor to the extent shown in the table below for Example R1, where the DVB feed rate varied over time.

[0235] Once the polymer conversion is in the range of 80%-85%, the reaction system is heated to 90°C. After 3 hours, the system is cooled to ambient temperature, and the beads are dehydrated, washed with water, and dried at ambient temperature.

[0236] Example R1: Results of testing the physical stability of SAC resin.

[0237] The copolymer prepared using the above method was converted into SAC resin and tested as described above. The results are shown below. Average results are shown for the replicate samples tested.

[0238] Method refers to whether the polymerization method has the incremental addition (GA) step of the present invention.

[0239] Initial DVB = The amount of DVB in the monomer droplet before polymerization is initiated (by weight, based on the weight of the monomer droplet).

[0240] Final DVB = The number of DVB polymerization units in the final polymer, by weight, based on the total weight of all monomers used throughout the process (including initial droplets and DVB fed during polymerization).

[0241] EXTSTART = Degree of reaction at the start of DVB feed

[0242] EXTSTOP = Degree of reaction at the end of DVB feeding

[0243] DIAM = Harmonized Average Diameter of Polymer Beads

[0244]

[0245] Example R2: Test results of sample E.

[0246] A strong base anion (SBA) exchange resin is prepared from the copolymer of Scheme E by a standard method of chloromethylation of chloromethyl ether followed by amination with trimethylamine, such that at least 95 mol% of the aromatic rings on the polymer units of the monofunctional vinyl monomers have linked amino groups.

[0247] For example, the AR test was performed on SBA resin. The results are as follows:

[0248]

[0249] Example R3: Catalytic Results

[0250] The catalytic activity of various functionalized resin samples in the reaction between phenol and acetone to prepare bisphenol A (BPA) was tested. Catalytic activity is characterized by the time to reach 60% conversion (“T60%”). Shorter times reflect higher levels of catalytic activity.

[0251] The catalytic reaction was carried out as follows: The resin was washed with phenol to remove moisture from the beads. Phenol was added to a glass reactor and heated to 50°C to melt the phenol. Dry resin loaded with an accelerator was added to the reactor and allowed to swell in the phenol. The reactor temperature was adjusted to between 45°C and 80°C. Acetone was added to the reactor. At several time intervals, small amounts of liquid sample were pipetted from the reactor into vials and mixed with an excess of N-methyl-N-(trimethylsilyl)trifluoroacetamide. The vials were incubated at 60°C for 30 minutes, then cooled to ambient temperature, and the BPA content was determined by gas chromatography.

[0252] The catalytic results are as follows. All samples shown have a total DVB polymerization unit content of 4.65%.

[0253] Example A-2a A-2b A-2c C-1Comp T60% (min) 52 52 47 71

[0254] Samples A-2a, A-2b, and A-2c prepared using the gradual addition method according to the invention achieved up to 60% conversion in a much shorter time than the control sample.

[0255] Example R4: Results after 30 days of storage at ambient temperature

[0256] The storage results are as follows:

[0257] Example: A-1Comp A-2a A-2b C-1Comp C-2 Electrical conductivity (μS) 169 127 160 189 126 absorbance 0.225 0.165 0.171 0.235 0.137

[0258] Each example resin exhibited lower conductivity and absorbance than its corresponding comparative example. Specifically, samples A-2a and A-2b showed lower conductivity and absorbance than comparative A-1Comp. Similarly, sample C-2 had lower conductivity and absorbance than comparative C-1Comp. This result indicates that the example resins possess greater stability during storage.

Claims

1. A method for preparing a polymer bead aggregate, wherein the beads comprise... (i) Based on the weight of the beads, 75 to 99% by weight of a polymerization unit of monofunctional vinyl monomers, and (ii) Based on the weight of the beads, 1 to 25% by weight of a polymeric unit of a multifunctional vinyl monomer. The vinyl monomers are selected from styrene monomers, acrylic monomers, and mixtures thereof; The method includes (a) Provide an aqueous suspension containing monomer droplets comprising an initiator, a monofunctional vinyl monomer, and a polyfunctional vinyl monomer; (b) Initiating polymerization of the monomers in the monomer droplets; (c) While the polymerization of the monomers in the monomer droplets is taking place, a monomer feed solution is added to the suspension. The monomers are added when the degree of polymerization (EXTSTART) in the monomer droplets is ≥0% and <10%. The addition is terminated when the degree of monomer polymerization (EXTSTOP) in the monomer droplets reaches 5% to 100% after EXTSTART, and... The amount EXDDIF = EXTSTOP - EXTSTART is 5% or higher; The feed solution contains a monomer in an amount of 90% to 100% by weight based on the weight of the feed solution; Based on the total weight of all monomers in the monomer droplet, the amount of polyfunctional vinyl monomers in the monomer droplet prior to polymerization initiation is ≥0.1% by weight and ≤10% by weight, and the feed solution contains a polyfunctional vinyl monomer in an amount of 50% to 100% by weight based on the weight of the feed solution. in, Prior to initiating polymerization, the monomer droplets contain 0.1% by weight or less of the polymer based on the weight of the monomer droplets.

2. The method as described in claim 1, wherein, EXTDIF is 20% or higher.

3. The method as described in claim 1 or 2, wherein, EXTSTOP is 85% or less.

4. The method as described in claim 1 or 2, wherein, The monofunctional vinyl monomer is a styrene monomer.

5. The method as described in claim 1 or 2, wherein, The monofunctional vinyl monomer contains styrene.

6. The method as described in claim 1 or 2, wherein, The multifunctional vinyl monomer comprises divinylbenzene.

7. The method as described in claim 1 or 2, wherein, The feed solution contains monomers dispersed in an aqueous medium.

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