Component addition polymerization

Abstract

To provide a collection of polymer beads.SOLUTION: A collection of polymeric beads, wherein the beads comprise (i) 75-99 wt% of a polymerized unit of a monofunctional vinyl monomer, based on the weight of the bead, and (ii) 1-25 wt% of a polymerized unit of a multifunctional vinyl monomer, based on the weight of the bead, wherein within each bead the average concentration of moles of polymerized unit of multifunctional vinyl monomer per cubic micrometer is MVAV; wherein within each bead a T1000 is a sequence of 1,000 unique linked polymerized monomer unit; wherein within each T1000: Wherein MVSEQ is the weight percent polymerized unit of multifunctional vinyl monomer, based on the weight of T1000; MVRATIO = MVSEQ / MVAV; and wherein 90% or more of the beads by volume are uniform beads, wherein uniform beads are beads in which 90% or more of all T1000 sequences have an MVRATIO of 1.5 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] A useful method for producing polymer beads is suspension polymerization, a process in which monomer droplets are suspended in an aqueous medium and then the monomers in the droplets are polymerized to form polymer beads. It is known that when a mixture of monomers is present in a monomer oil droplet, the monomers typically react at different rates, thus forming heterogeneous polymer beads. For example, it is believed that one or more regions within the oil droplet may form a copolymer having a higher proportion of polymerized units of the more reactive monomer than the average proportion of the more reactive monomer present in the mixture of monomers in the entire oil droplet. It is believed that such regions rich in polymerized units of the more reactive monomer are particularly likely to form early in the polymerization process. It is further believed that regions relatively poor in polymerized units of the more reactive monomer will form later in the polymerization process. Therefore, it is believed that the resulting polymer beads will be heterogeneous, with some polymer segments within the bead having a different concentration of polymerized units of the more reactive monomer than other polymer segments. It is predicted that this heterogeneity will be detrimental to some of the performance properties of the polymer beads. [Background technology]

[0002] It would be desirable to provide a method for producing polymer beads that involves polymerization of a mixture of monomers that results in polymer beads with a relatively uniform distribution of polymerized units of each monomer. More generally, it would be even more desirable to provide a process in which the degree and nature of heterogeneity can be controlled, rather than relying solely on the relative reactivities of the monomers to produce uncontrolled heterogeneity. It would also be desirable to provide a process in which mass transfer of monomers being fed into the monomer droplets during polymerization, where polymerization is occurring, proceeds efficiently or consistently, or both, where "consistently" means proceeding extraordinarily nearly equally from one batch (i.e., one polymerization process) to another.

[0003] Often, after polymerization is complete, the polymer beads are functionalized, i.e., they are subjected to one or more chemical reactions to attach ionic functional groups, which can be anionic or cationic groups, to the polymer beads.

[0004] An important property of polymer beads is mechanical strength. Mechanical strength may be evaluated for polymer beads immediately after polymerization or for functionalized beads. Bead mechanical strength can be measured directly, for example, by measuring the force required to crush the beads. Higher crush strength is desirable, especially for functionalized beads. Mechanical strength can also be measured for polymer beads functionalized with either anionic or cationic groups by exposing the beads to alternating solutions containing different types of ions. Exposure to these alternating solutions causes osmotic stress that causes some polymer beads to break. It is desirable that as few functionalized beads as possible break under osmotic stress.

[0005] U.S. Patent No. 3,792,029 describes a suspension polymerization process in which, during the suspension polymerization of a monomer mixture, an emulsion containing a more reactive monomer is added to the suspension while the polymerization is occurring. It would be desirable to provide a process in which neat monomer is added to the suspension polymerization process. It would also be desirable to provide polymer beads with one or more of the following benefits: relatively uniform distribution of polymerized units of each monomer, high crush strength, consistent and / or efficient mass transfer of the fed monomer to the monomer oil droplets, and / or high resistance to osmotic stress.

[0006] Furthermore, in the process described by U.S. Pat. No. 3,792,029, the emulsion added to the suspension during polymerization contains a mixture of more reactive and less reactive monomers. In the mixture added to the suspension described by U.S. Pat. No. 3,792,029, there is significantly more (by weight) less reactive monomer than more reactive monomer. It is believed that the process described by U.S. Pat. No. 3,792,029 can result in one or more of the following undesirable effects: the process can cause an increase in bead size, which places undesirable stress on the polymer network; and / or the process can result in the formation of inhomogeneities in the bead structure, for example, by forming an interpenetrating polymer network. It would be desirable to provide a process in which the monomer added to the suspension during polymerization is 50% or more by weight of the more reactive monomer. It would also be desirable to provide a process that avoids the undesirable effects of the process of U.S. Pat. No. 3,792,029. Summary of the Invention [Means for solving the problem]

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

[0008] A first aspect of the present invention is a method for producing a collection of polymer beads, the beads comprising: (i) 75 to 99% by weight of polymerized units of a monofunctional vinyl monomer based on the weight of the beads; (ii) 1 to 25% by weight of polymerized units of a polyfunctional vinyl monomer based on the weight of the beads; Including, The method comprises: (a) providing an aqueous suspension of monomer oil droplets comprising an initiator, a monofunctional vinyl monomer, and a multifunctional vinyl monomer; (b) initiating polymerization of the monomers in the monomer oil droplets; (c) adding a monomer feed solution to the suspension while polymerization of the monomers in the monomer oil droplets is occurring; This addition begins when the degree of polymerization (EXTSTART) of the monomer in the monomer oil droplet is between 0% and 50%. This addition ends when the degree of polymerization of the monomer in the monomer oil droplet after EXTSTART (EXTSTOP) is between 5% and 100%; the feed solution comprises monomer in an amount of 90% to 100% by weight based on the weight of the feed solution; the feed solution comprises a multifunctional vinyl monomer in an amount of 50% to 100% by weight based on the weight of the feed solution; The method includes:

[0009] A second aspect of the present invention is a collection of polymer beads, the beads comprising: (i) 75 to 99% by weight of polymerized units of a monofunctional vinyl monomer based on the weight of the beads; (ii) 1 to 25% by weight of polymerized units of a polyfunctional vinyl monomer based on the weight of the beads; Including, Within each bead, the average concentration of moles of polymerized units of the polyfunctional vinyl monomer per cubic micrometer is MVAV; Within each bead, T1000 is a sequence of 1,000 unique linked polymerized monomer units; within each T1000, MVSEQ is the weight percent polymerized units of the multifunctional vinyl monomer, based on the weight of the T1000; MVRATIO=MVSEQ / MVAV; and 90% or more of the beads by volume are uniform beads (wherein 90% or more of all T1000 sequences have a MVRATIO of 1.5 or less). It is a collection of beads.

[0010] A third aspect of the present invention is a method for treating water, wherein the water contains dissolved ions including undesirable cations, the method comprising: (a) (i) 75 to 99% by weight of polymerized units of a monofunctional vinyl monomer based on the weight of the beads; (ii) 1 to 25% by weight of polymerized units of a polyfunctional vinyl monomer, based on the weight of the beads; (iii) a functional group attached to the polymer bead and having a charge opposite to that of the undesired ion; (iv) ions that are not bound to the polymer beads and have the same charge as the undesired ions; providing a collection of functionalized polymer beads comprising: Within each bead, the average concentration of moles of polymerized units of the polyfunctional vinyl monomer per cubic micrometer is MVAV; Within each bead, T1000 is a sequence of 1,000 unique linked polymerized monomer units; within each T1000, MVSEQ is the weight percent polymerized units of the multifunctional vinyl monomer, based on the weight of the T1000; MVRATIO=MVSEQ / MVAV; and 90% or more of the beads by volume are uniform beads (wherein 90% or more of all T1000 sequences have a MVRATIO of 1.5 or less). Process and; (b) then passing water through the bed of polymer bead aggregates to exchange the undesired ions for ions (IV); (c) then passing a regeneration solution containing dissolved ions (V) of the same chemical species as ions (IV) through a bed of polymer beads to exchange ions (V) for the undesired ions; The method includes:

[0011] A fourth aspect of the present invention is a method for producing 2,2-bis(4-hydroxyphenyl)propane, comprising the steps of condensing phenol with acetone in the presence of an acid catalyst to form the dihydric phenol 2,2-bis(4-hydroxyphenyl)propane; The acid catalyst comprises a collection of sulfonated polymer beads, the sulfonated polymer beads comprising: (i) 75 to 99% by weight of polymerized units of a monofunctional vinyl monomer based on the weight of the beads; (ii) 1 to 25% by weight of polymerized units of a polyfunctional vinyl monomer based on the weight of the beads; Including, Within each bead, the average concentration of moles of polymerized units of the polyfunctional vinyl monomer per cubic micrometer is MVAV; Within each bead, T1000 is a sequence of 1,000 unique linked polymerized monomer units; within each T1000, MVSEQ is the weight percent polymerized units of the multifunctional vinyl monomer, based on the weight of the T1000; MVRATIO=MVSEQ / MVAV; and 90% or more of the beads by volume are uniform beads (wherein 90% or more of all T1000 sequences have a MVRATIO of 1.5 or less). It is a method. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following is a detailed description of the present invention.

[0013] As used herein, the following terms have the definitions specified unless the context clearly dictates otherwise.

[0014] As used herein, a "polymer" is a relatively large molecule composed of the reaction product of smaller chemical repeating units. Polymers can have structures that are linear, branched, star-shaped, looped, hyperbranched, crosslinked, or a combination thereof; polymers can have a single type of repeating unit (a "homopolymer"), or they can have two or more types of repeating units (a "copolymer"). Copolymers can have the various types of repeating units arranged randomly, in order, in blocks, in other arrangements, or in any mixture or combination thereof.

[0015] Molecules that can react with each other to form repeat units of a polymer are known herein as "monomers." The repeat units so formed are known herein as "polymerized units" of the monomer.

[0016] Vinyl monomers have the structure: [ka] (In the formula, R 1 , R 2 , R 3 , and R 4 each is independently hydrogen, halogen, an aliphatic group (such as, for example, an alkyl group), a substituted aliphatic group, an aryl group, a substituted aryl group, another substituted or unsubstituted organic group, or any combination thereof. Vinyl monomers can undergo free radical polymerization to form polymers. Some vinyl monomers have the R 1 , R 2 , R 3 , and R 4 such vinyl monomers are known herein as polyfunctional vinyl monomers. Vinyl monomers with exactly one polymerizable carbon-carbon double bond are known herein as monofunctional vinyl monomers.

[0017] Styrene-based monomers are R 1and R 2 are hydrogen and R 3 is hydrogen or alkyl, and -R 4 But the structure [ka] (In the formula, R 5 , R 6 , R 7 , R 8 , and R 9 each is independently hydrogen, halogen, an aliphatic group (such as, for example, an alkyl group or a vinyl group), a substituted aliphatic group, an aryl group, a substituted aryl group, another substituted or unsubstituted organic group, or any combination thereof. It is a vinyl monomer having the formula:

[0018] The reaction between monomers to form one or more polymers is referred to herein as a polymerization process.

[0019] As used herein, an initiator is a molecule that is stable at ambient conditions but can under certain conditions generate one or more fragments having free radicals that can interact with monomers to initiate the free radical polymerization process. Conditions that generate free radical fragments include, for example, high temperature, participation in a redox reaction, exposure to ultraviolet and / or ionizing radiation, or a combination thereof.

[0020] As used herein, the phrase "total monomers" refers to all of the monomers used to make the polymer, including those present when the initiation of polymerization begins and all of those that may be added during the polymerization process.

[0021] A polymer is said herein to contain polymerized units of the monomers used to make the polymer, even if some or all of those polymerized units are modified after polymerization by the addition of one or more functional groups. For example, a copolymer made from styrene and DVB in a 90:10 styrene:DVB weight ratio is said to have 90% polymerized units by weight of styrene. If that copolymer is modified by reaction with sulfuric acid to replace some of the hydrogen atoms on the aromatic rings with sulfonic acid groups, the resulting functionalized polymer would still be said to have 90% polymerized units by weight of styrene.

[0022] As used herein, an inhibitor is a molecule that reacts with a vinyl monomer radical or with a radical on a growing vinyl polymer chain to form a new radical that does not participate in vinyl polymerization.

[0023] Macroporous polymer beads have a porous structure with an average pore size of 20 nm or more. Pore size is measured using the Brunauer-Emmett-Teller (BET) method using nitrogen gas. Macroporous polymer beads are typically fabricated by incorporating a porogen into monomer oil droplets. The porogen is soluble in the monomer, but the polymer is insoluble in the porogen, resulting in phase-separated domains of the porogen remaining as the polymer forms. After polymerization, the porogen is removed by evaporation or washing with a solvent. The porous structure of the polymer beads is the empty space left behind when the porogen is removed from its phase-separated domains.

[0024] Gel-type polymer beads are produced without the use of porogens. The pores in gel-type polymer beads are the free volume between atoms in the entangled, possibly cross-linked, polymer chains of the polymer beads. The pores in gel-type polymer beads are smaller than 20 nm. In some cases, the pores in gel-type resins are too small to be detected using the BET method.

[0025] Two ions or ionic groups are said to have the "same" charge herein if they are both anionic or both cationic, regardless of the magnitude of the charge. For example, sulfonate groups (i.e., -SO3 - ) is a carbonate ion (i.e., CO3 2- ) and have the same charge. Similarly, two ions or ionic groups are said to have "opposite" charges herein if one is anionic and the other is cationic, regardless of the magnitude of the charges. A carboxylic acid group is considered to comprise a carboxylate anion and a hydrogen cation, and a sulfonic acid group is considered to comprise a sulfonate anion and a hydrogen cation.

[0026] As used herein, ion exchange is a process in which a solution contacts an ion exchange resin. Prior to contact with the solution, the ion exchange resin has functional groups of a certain charge and ions of the opposite charge associated with the functional groups. When the solution contacts the ion exchange resin, some ions in the solution bind to the ion exchange resin by exchanging places with ions of the same charge that were associated with the functional groups on the ion exchange resin.

[0027] A compound is said herein to be water-soluble if 5 grams or more of the compound forms a stable solution in 100 ml of water at 25° C. In the case of some water-soluble polymers, the water may need to be heated above 25° C. to dissolve the polymer, but after cooling to 25° C., the solution is stable if kept at 25° C.

[0028] A suspension is a composition having particles of one substance distributed throughout a liquid medium. The distributed particles may be liquid or solid; distributed liquid particles are called oil droplets. A medium is "aqueous" if it contains 90% or more water by weight, based on the weight of the medium. A 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 mechanical agitation may or may not be required to keep the particles distributed in the medium.

[0029] Polymer beads are particles containing 90% or more by weight of organic polymers, based on the weight of the particle. Polymer beads are spherical or nearly spherical. Polymer beads are characterized by their radius. If the bead is not spherical, the radius of the bead is interpreted herein as the radius of a "reference sphere," an imaginary sphere having the same volume as the bead. The sphericity of a particle is assessed by its "sphericity," represented by the Greek letter Ψ. For a particle with a volume VP and major axes of lengths a (long), b (medium), and c (short), the sphericity is:

number

[0030] The unit of volume is "cubic micrometer" (μm 3 ), as used herein, refers to the volume of a cube having an edge length of 1 micrometer.

[0031] As used herein, "ambient temperature" is synonymous with "room temperature," which is approximately 23°C.

[0032] The particle aggregate has a harmonic mean diameter (HMD) defined as follows:

number

[0033] Ratios are characterized herein as follows. For example, when a ratio is said to be 5:1 or greater, it means that the ratio can be 5:1 or 6:1 or 100:1, but not 4:1. Stated generally, when a ratio is said to be X:1 or greater, it means that the ratio is Y:1 (where Y is X or greater). Similarly, for example, when a ratio is said to be 2:1 or less, it means that the ratio can be 2:1 or 1:1 or 0.001:1, but not 3:1. Stated generally, when a ratio is said to be Z:1 or less, it means that the ratio is W:1 (where W is Z or less).

[0034] The process of the present invention involves monomer droplets containing a vinyl monomer and an initiator. The following is a description of the monomer droplets as they exist prior to the initiation of polymerization.

[0035] Preferably, the amount of monomer in the monomer oil droplets is 80% or more, more preferably 90% or more, more preferably 95% or more, by weight based on the weight of the oil droplets.

[0036] Preferred vinyl monomers are styrenic monomers, acrylic monomers, and mixtures thereof. Preferably, all of the monomers used are selected from styrenic monomers, acrylic monomers, and mixtures thereof. More preferably, all of the monomers used are selected from styrenic monomers. The vinyl monomers include one or more monofunctional vinyl monomers. Preferred monofunctional vinyl monomers are acrylic and styrenic monofunctional monomers; monofunctional styrenic monomers are more preferred; styrene is more preferred. The vinyl monomers also include one or more multifunctional vinyl monomers. Preferred multifunctional vinyl monomers are multifunctional styrenic monomers; divinylbenzene is more preferred. Preferably, the amount of vinyl chloride is 0 to 0.1% by weight, more preferably 0 to 0.01%, more preferably 0%, based on the total weight of all monomers.

[0037] Preferably, the amount of styrene-based monomer in the oil droplets before the start of polymerization is, by weight based on the weight of all monomers in the oil droplets, 50% or more; more preferably 75% or more; more preferably 88% or more; more preferably 94% or more; more preferably 97% or more; more preferably 100%.

[0038] Preferably, the amount of monofunctional vinyl monomer in the oil droplets before the start of polymerization is, by weight, based on the weight of all monomers in the oil droplets, 75% or more; more preferably 80% or more; more preferably 85% or more; more preferably 90% or more; more preferably 94% or more. Preferably, the amount of monofunctional vinyl monomer in the oil droplets is, by weight, based on the weight of all monomers in the oil droplets, 99.9% or less; more preferably 99% or less; more preferably 98.5% or less.

[0039] Preferably, the amount of polyfunctional vinyl monomer in the oil droplets before the start of polymerization is 0.1% or more, more preferably 1% or more, more preferably 1.5% or more, by weight based on the weight of all monomers in the oil droplets. Preferably, the amount of polyfunctional vinyl monomer in the oil droplets is less than 25%, more preferably 20% or less, more preferably 15% or less, more preferably 10% or less, more preferably 6% or less, by weight based on the weight of all monomers in the oil droplets.

[0040] It is useful to characterize the amount of multifunctional vinyl monomer in the oil droplets prior to the start of polymerization ("MFMPRIOR") as a weight percentage of total monomers. Preferably, MFMPRIOR is 0.1% or greater; more preferably 0.5% or greater; more preferably 1% or greater; more preferably 1.5% or greater; more preferably 2% or greater. Preferably, MFMPRIOR is 10% or less; more preferably 8% or less; more preferably 6% or less.

[0041] ratio MFMRATIO=100*MFMPRIOR / MFMTOTAL where MFMTOTAL is the total weight percentage of multifunctional monomers used in the entire polymerization process, including multifunctional monomers present before initiation and multifunctional monomers added after initiation. It is also useful to characterize the MFMRATIO. Preferably, MFMRATIO is 10% or greater; more preferably, 20% or greater; more preferably, 30% or greater. Preferably, MFMRATIO is 80% or less; more preferably, 70% or less; more preferably, 60% or less.

[0042] The method of the present invention involves the suspension of monomer oil droplets in an aqueous medium. Preferably, the total amount of monomer is 5% or more, more preferably 10% or more, more preferably 15% or more, by weight, based on the total weight of the suspension. Preferably, the total amount of monomer is 55% or less, more preferably 35% or less, more preferably 30% or less, by weight, based on the total weight of the suspension.

[0043] The monomer oil droplets contain 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. Organic peroxide and hydroperoxide initiators are preferred; peroxide initiators are more preferred; benzoyl peroxide and its derivatives are more preferred; and benzoyl peroxide is more preferred. Preferably, the weight ratio of initiator to total monomer is 0.0002:1 or more; more preferably 0.0005:1 or more; more preferably 0.001:1 or more; more preferably 0.002:1 or more. Preferably, the weight ratio of initiator to total monomer is 0.02:1 or less; more preferably 0.01:1 or less; more preferably 0.007:1 or less.

[0044] The monomer oil droplets optionally contain one or more porogens. Preferably, little or no porogen is present. That is, preferably, porogen is absent or, if present, the amount of porogen is 1% or less by weight, based on the weight of the monomer oil droplets; more preferably, 0.1% or less. More preferably, no porogen is present in the monomer oil droplets.

[0045] Monomers, as typically supplied by manufacturers, contain relatively small amounts of inhibitors to prevent unintended polymerization during storage. Common inhibitors are quinones (e.g., 1,4-benzoquinone) and hindered phenols (e.g., tert-butylpyrocatechol, also known as 4-tert-butylcatechol).

[0046] Preferably, before the start of polymerization, the monomer oil droplets contain either no polymer of any kind or only small amounts of polymer of any kind, i.e., if any polymer is present in the monomer oil droplets, the total amount of polymer is preferably 0.1% or less by weight based on the weight of the monomer oil droplets.

[0047] The aqueous medium preferably contains one or more water-soluble polymers. The water-soluble polymers are believed to stabilize the monomer oil droplets against coalescence. Suitable water-soluble polymers can be any of a wide 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, polymers of diallyl ammonium chloride (DADMAC) are preferred. Among water-soluble derivatives of cellulose, carboxymethyl methylcellulose is preferred. Among polyvinyl alcohol polymers, those with a degree of hydrolysis of 80% to 90% are preferred. Preferably, the aqueous medium contains one or more water-soluble polyvinyl alcohol polymers and one or more water-soluble derivatives of cellulose.

[0048] When one or more water-soluble polymers are used, preferably the total amount of water-soluble polymers is, by weight based on the weight of the aqueous medium, 0.02% or more; more preferably 0.05% or more; more preferably 0.1% or more. When one or more water-soluble polymers are used, preferably the total amount of water-soluble polymers is, by weight based on the weight of water, 2% or less; more preferably 1% or less; more preferably 0.5% or less.

[0049] Other methods for stabilizing the monomer oil droplets are also suitable, which can be used instead of or in addition to one or more water-soluble polymers. For example, solid particles smaller than the monomer oil droplets can be present on the surface of the oil droplets to stabilize them. An example of such solid particles is colloidal silica particles.

[0050] The aqueous suspension of monomer oil droplets optionally contains one or more suspending aids. The suspending aids are believed to stabilize the monomer oil droplets. The suspending aids may be introduced by adding them to the aqueous phase, by adding them to the monomer oil droplets, or by a combination thereof. Regardless of how the suspending aid is introduced, the preferred amount of suspending aid is 0.001% to 0.1% by weight, based on the weight of the monomer oil droplets. A preferred suspending aid is 4-vinylphenylboronic acid.

[0051] The nature of the step of initiating polymerization depends to some extent on the nature of the initiator used. For example, if a thermal initiator is used, the initiation conditions include establishing a temperature above 25°C that is sufficiently high to cause a significant portion of the initiator molecules to decompose and form free radicals. As another example, if a photoinitiator is used, the initiation conditions include exposing the initiator to radiation of a sufficiently low wavelength and high enough intensity to cause a significant portion of the initiator molecules to decompose and form free radicals. As another example, if the initiator is a redox initiator, the initiation conditions include the presence of both an oxidizing agent and a reducing agent at concentrations high enough to generate a significant number of free radicals. Preferably, a thermal initiator is used. Preferably, the initiation conditions include a temperature of 55°C or higher, more preferably 70°C or higher. That is, preferably, the suspension is provided at a temperature below 40°C, and the initiator present does not generate a significant number of free radicals at that temperature. Next, preferably, step (b) includes raising the temperature to the initiation conditions.

[0052] After step (b), at any instant while the polymerization is occurring, the degree of free radical polymerization in the vessel containing the suspension can be characterized as follows: Degree of polymerization=100*PM / TM where PM is the mass of polymer formed by the free radical polymerization process, and TM is the total mass of monomer added to the vessel up to that moment (including the initial monomer droplets and monomer added during the course of the polymerization).

[0053] Prior to the start of the polymerization process, oil droplets are present in suspension, and the oil droplets contain vinyl monomers and an initiator. Preferably, the oil droplets are distributed throughout the aqueous medium. Preferably, the aqueous medium composition contains water in an amount of 90% or more, more preferably 95% or more, more preferably 97% or more, by weight based on the weight of the aqueous medium. Compounds dissolved in water are considered to be part of the continuous liquid medium. Preferably, the volume average particle size of the oil droplets is 50 μm to 1,500 μm.

[0054] In the process of the present invention, once polymerization in the monomer droplets has begun, a feed solution is added to the suspension. The act of adding monomer to the suspension after polymerization has begun is known herein as "gradual addition," or GA. The feed solution can be added at any rate. The rate of addition of the feed solution can be constant or can be faster at times than at others. The addition of the feed solution can be accomplished in a single continuous addition (which can be done rapidly or slowly), or the addition of the feed solution can be interrupted one or more times.

[0055] Addition of Feed Solution begins when the reaction progress is at a point designated herein as "EXT START." EXT START is between 0% and 50%, inclusive. Preferably, EXT START is 40% or less; more preferably, 30% or less; more preferably, 20% or less; more preferably, 10% or less.

[0056] The reaction progress "EXTSTOP" is the reaction progress at which the last of the feed solution is added to the suspension. No feed solution is added to the suspension after EXTSTOP. EXTSTOP is 5% to 100%. Preferably, EXTSTOP is 85% or less. Preferably, the amount EXTDIFF=EXTSTOP-EXTSTART is 5% or more; more preferably 20% or more; more preferably 50% or more; more preferably 60% or more.

[0057] Preferably, the feed solution contains total vinyl monomers of all types in an amount, by weight based on the weight of the feed solution, of 75% or more; more preferably 85% or more; more preferably 95% or more; more preferably 99% or more.

[0058] The amount of polyfunctional monomer in the feed solution is preferably 30% by weight, based on the weight of the feed solution; preferably 40% or more; more preferably 45% or more; more preferably 50% or more; more preferably 55% or more; more preferably 60% or more. When the polyfunctional monomer is divinylbenzene (DVB), it is preferred to use technical grade DVB, which is a mixture containing approximately 63% by weight of chemically pure DVB and approximately 37% by weight of ethylvinylbenzene (EVB), with other impurities totaling less than 1% by weight. When a composition is stated herein as containing a certain amount of DVB, it is assumed that the composition contains EVB in a weight ratio of approximately 37:63 EVB:DVB in addition to the stated amount of DVB. If such technical grade DVB is used, preferably the amount of technical grade DVB in the feed solution is, by weight based on the weight of the feed solution, 50% or more; more preferably 60% or more; more preferably 70% or more; more preferably 80% or more; more preferably 90% or more; more preferably 95% or more.

[0059] Preferably, the feed solution contains either no initiator or contains initiator in an amount, in parts per million by weight, of 100 ppm or less; more preferably 10 ppm or less; more preferably 1 ppm or less.

[0060] Preferably, the feed solution either contains no water or contains no more than 20% water; more preferably no more than 10%; more preferably no more than 3%; more preferably no more than 1%; more preferably no more than 0.3%; more preferably no more than 0.1% water, by weight based on the weight of the feed solution.

[0061] Also envisioned are embodiments in which the feed solution is replaced with a feed composition that is a dispersion of monomer oil droplets in an aqueous medium ("dispersion feed" embodiments). Such a dispersion can be any type of dispersion, such as, for example, a suspension, emulsion, microemulsion, or nanoemulsion. Such a dispersion optionally contains one or more water-soluble polymers, one or more surfactants, one or more dispersants, or mixtures thereof, as described above. Among dispersion feed embodiments, emulsions are preferred. Among emulsions, those containing one or more anionic surfactants are preferred.

[0062] In a dispersive feed embodiment, the total amount of monomers in the feed composition is, by weight, based on the weight of the feed composition, 5% or more; more preferably 10% or more; more preferably 20% or more; more preferably 40% or more. In a dispersive feed embodiment, the total amount of monomers in the feed composition is, by weight, based on the weight of the feed composition, 60% or less; more preferably 55% or less.

[0063] In a dispersed feed embodiment, it is useful to characterize the amount of multifunctional vinyl monomer as a weight percentage of the monomer content of the feed composition. In a dispersed embodiment, preferably, the amount of multifunctional vinyl monomer is 50% to 100%; more preferably 75% to 100%; more preferably 90% to 100%; more preferably 95% to 100% by weight, based on the total weight of monomers in the feed composition.

[0064] In the dispersed feed embodiment, the suitable and preferred conditions for feeding during polymerization (such as reaction progress) are the same as those described above.

[0065] The present invention also includes a collection of polymer beads. The collection of polymer beads is preferably produced by the method of the present invention. The polymer beads contain a polymer. The polymer beads are particles that are solid at 25°C and contain polymer in an amount of 90% or more, more preferably 95% or more, by weight based on the weight of the polymer particles.

[0066] The polymer beads can be macroporous beads or gel beads, with gel beads being preferred.

[0067] Preferably, the polymer beads have a volume average particle size of 50 μm or more, more preferably 100 μm or more, more preferably 200 μm or more, more preferably 400 μm or more. Preferably, the polymer beads have a volume average particle size of 1,500 μm or less, more preferably 1,000 μm or less.

[0068] The preferred polymers in the polymer particles are those formed by free radical polymerization of the preferred vinyl monomers described above. Preferably, the polymer contains polymerized units of styrene monomers in an amount of 5% or more, more preferably 25% or more, more preferably 50% or more, more preferably 75% or more, more preferably 95% or more, by weight based on the weight of the polymer. The types of monomers preferred as polymerized units of the polymer are the same as those described above as preferred for use in the polymerization process.

[0069] Preferred polymers have polymerized units of multifunctional vinyl monomers in an amount, by weight, based on the weight of the polymer, of 1% or more; more preferably 1.5% or more; more preferably 2% or more. Preferred polymers have polymerized units of multifunctional vinyl monomers in an amount, by weight, based on the weight of the polymer, of 25% or less; more preferably 20% or less; more preferably 15% or less; more preferably 11% or less; more preferably 6% or less.

[0070] Preferred polymers have polymerized units of monofunctional vinyl monomers in an amount, by weight, based on the weight of the polymer, of 99.7% or less; more preferably 99.5% or less; more preferably 99% or less; more preferably 98.5% or less. Preferred polymers have polymerized units of monofunctional vinyl monomers in an amount, by weight, based on the weight of the polymer, of 75% or more; more preferably 80% or more; more preferably 85% or more; more preferably 90% or more; more preferably 94% or more.

[0071] The polymer in the polymer beads has a relatively uniform distribution of polymerized units of the polyfunctional vinyl monomer. The uniformity of the distribution of polymerized units of the polyfunctional vinyl monomer can be characterized as follows: MVAV = average concentration of polymerized units of polyfunctional vinyl monomer within a single bead (in moles per cubic micrometer) T1000 = 1,000 sequences of linked polymerized monomer units MVSEQ = weight percent of polymerized units of polyfunctional vinyl monomer for a specific T1000, based on the weight of T1000 MVRATIO=MVSEQ / MVAV

[0072] In selecting T1000, any polymerized unit can be selected as the first unit in the sequence. Then, any polymerized unit covalently bonded to the first polymerized unit can be selected as the second unit in the sequence. Similarly, each selected unit is covalently bonded to the previous unit in the sequence. No polymerized unit appears twice in the T1000 sequence. When 1000 polymerized units have been selected, the T1000 sequence is complete. Another way to describe the T1000 selection process is to state that the first polymerized unit is carefully selected, and then a path is traced along the covalently bonded polymerized units until the path is 1000 units long. The path is selected so that it does not cross itself. Each bead contains many T1000 sequences. The T1000 sequences are not physically altered or removed from the bead. The T1000 sequences are a tool for characterizing the uniformity of polymer beads.

[0073] A bead is considered "uniform" if it has a relatively even distribution of polymerized units of polyfunctional vinyl monomer. That is, a bead is uniform if, by sequence number, 90% or more of all T1000 sequences in the bead have an MVRATIO of 1.5 or less. Preferred beads have a higher degree of uniformity, such that, by sequence number, 90% or more of all T1000 sequences in the bead have an MVRATIO of 1.25 or less.

[0074] In the population of beads of the present invention, most of the beads are uniform. That is, the amount of beads that are uniform by volume is 90% or more; more preferably 95% or more; more preferably 99% or more. More preferably, the amount of beads in which 90% or more of all T1000 sequences, by sequence number, have an MVRATIO of 1.25 or less is 90% or more; more preferably 95% or more; more preferably 99% or more.

[0075] It is useful to consider the percentage of T1000 sequences, by number of sequences, that have an MVRATIO of 0.5 or less. Preferably, by number of sequences, 35% or less of the T1000 sequences will have an MVRATIO of 0.5 or less. More preferably, by number of sequences, 25% or less of the T1000 sequences will have an MVRATIO of 0.5 or less.

[0076] The polymeric beads preferably have an average sphericity of 0.8 or greater; more preferably 0.85 or greater; more preferably 0.9 or greater; more preferably 0.95 or greater.

[0077] A preferred use of the polymers produced by the free radical polymerization process of the present invention is in a conversion process to produce ion exchange resins. Ion exchange resins fall into the following categories: Weakly basic anion exchange resins have pendant amino groups that are primary, secondary, or tertiary; strongly basic anion exchange resins have pendant quaternary amino groups; weakly acidic cation exchange resins have pendant carboxylic acid groups; and strongly acidic cation exchange resins have pendant sulfonic acid groups. When any of these pendant functional groups are attached to a polymer bead, the bead is said to be a "functionalized resin."

[0078] Typically, in preparing weakly basic anion exchange resins from polymer beads such as crosslinked polystyrene beads, the beads are advantageously haloalkylated, preferably halomethylated, most preferably chloromethylated, and ionically active exchange groups are then attached to the haloalkylated copolymer. Typically, the haloalkylation reaction involves swelling the crosslinked addition copolymer with a haloalkylating 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 haloalkylating agent in the presence of a Friedel-Crafts catalyst such as zinc chloride, iron chloride, or aluminum chloride. Typically, weakly basic anion exchange resins are prepared by reacting a haloalkylated copolymer with ammonia, a primary amine, or a secondary amine. Typically, strongly basic anion exchange resins are prepared by reacting a haloalkylated copolymer with a tertiary amine.

[0079] Typically, in the preparation of strongly acidic cation exchange resins from polymeric beads, such as cross-linked polystyrene beads, the beads are advantageously sulfonated. Generally, the beads are swollen using a suitable swelling agent, and the swollen beads are reacted with a sulfonating agent, such as sulfuric acid or chlorosulfonic acid or sulfur trioxide, or mixtures thereof.

[0080] A collection of functionalized polymer beads typically contains water in addition to the polymer beads themselves. Typically, the process used to produce functionalized polymer beads involves contact between the functionalized polymer beads and water, and although excess liquid water is removed, a significant amount of water remains as part of the collection of functionalized polymer beads. The water is believed to be adsorbed into the functionalized polymer beads. The amount of water is typically 30% to 90% by weight based on the weight of the collection of functionalized polymer beads.

[0081] It is believed that the polymeric beads of the present invention will be useful for a variety of purposes. Functionalized polymeric beads will be useful for many of the purposes for which ion exchange resins are useful. For example, it is expected that the increased crush strength and osmotic stability of the functionalized polymeric beads of the present invention will make these beads useful in their preferred use as water purification resins or as catalysts. When the functionalized polymeric beads of the present invention are used as catalysts, it is expected that the functionalized polymeric beads of the present invention will improve the reaction rate of the reaction being catalyzed. The uniformity of the spatial distribution of polymerized units of multifunctional vinyl monomers in the functionalized polymeric beads of the present invention is expected to have the effect that more sites on the beads are accessible for catalysis, which will also have the optimal concentration of polymerized units of multifunctional monomers for optimal reaction rate, compared to previously known beads.

[0082] A preferred method of using the polymer beads of the present invention involves passing a liquid through a bed of polymer beads, i.e., a collection of polymer beads is placed in a container that traps the polymer beads in place, has an inlet for liquid to enter the container, causes the liquid to flow through the container in intimate contact with the polymer beads, and has an outlet for liquid to exit the container.

[0083] When the intended use is water purification, the functionalized resin is used to remove undesired ions from water. The resin has a functional group (herein "functional group (iii)"). The resin is selected so that functional group (iii) has a charge opposite to that on the undesired ion. Prior to purification, functional group (iii) is associated with a counterion (herein "ion (iv)") that is not bound to the resin. Ion (iv) has the same charge as the undesired ion. Preferably, the proportion of functional group (iii) associated with ion (iv) is, on a molar basis, 50% or more; more preferably 75% or more; more preferably 92% or more.

[0084] In the "loading" step, water to be purified is passed through a bed of resin, and undesirable ions in the water are loaded onto the functionalized polymer beads by exchanging with ion (iv) and associating with functional group (iii). Eventually, the resin will be loaded at or near its capacity for retaining the undesired ions. Next, to remove the undesired resin, the functionalized polymer beads undergo a "regeneration" step in which a regeneration solution is passed through the bed of resin. The regeneration solution contains dissolved ions, such as ion (v), which is the same chemical species as ion (iv). Ion (v) replaces the undesired ions on the resin, and the undesired ions are removed along with the regeneration solution.

[0085] Preferably, the cycle of loading and regeneration is repeated. That is, a new batch containing the same undesired ions is passed through the resin bed to load the resin with the undesired ions, and the resin is then regenerated as described above. Preferably, the loading and regeneration process is repeated 10 or more times; more preferably 20 or more times.

[0086] Repeated cycles of loading and regeneration cause osmotic shock to the functionalized polymer beads because the equilibrium water content (and therefore bead size) is a function of the specific counterion. 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.

[0087] The above discussion envisions a single undesired ion of a fixed charge. It is envisioned that if the water also contains a second undesired ion of opposite charge to the first undesired ion, the water could be contacted with a second resin having functional groups of opposite charge to the charge on the functional groups on the first resin. The two resins may be used sequentially or mixed together.

[0088] For example, polymer beads functionalized with sulfonic acid groups are strong acid cation exchange resins ("SAC"). SAC could be used to remove unwanted sodium ions from water. Initially, the SAC could be in the hydrogen form; that is, more than half of the sulfonate groups (on a molar basis) are cations with the counterion H + Next, in a process called "loading" the resin, an aqueous solution of NaCl could be passed through the bed of SAC to exchange the hydrogen ions for sodium ions, so that the sodium ions are retained on the SAC, placing the resin in the sodium form. Eventually, the SAC reaches or approaches the limit of its capacity to retain sodium ions. The SAC can then be regenerated, for example, by passing an aqueous solution of H2SO4 through the bed of SAC, to return the resin to the hydrogen form. Such cycles of loading, followed by regeneration, place 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 down some of the beads.

[0089] To take another example, polymer beads functionalized with quaternary ammonium groups are strong basic anion exchange resins ("SBA"). SBA could be used to remove unwanted chloride ions from water. Initially, the SBA could be in the hydroxide form; that is, more than half of the quaternary ammonium groups (on a molar basis) are in the hydroxide form, i.e., more than half of the quaternary ammonium groups ... - Next, in a process called "loading" the resin, an aqueous solution of NaCl could be passed through the bed of SBA to exchange the hydroxide ions for chloride ions, resulting in the chloride ions being retained on the SBA. Eventually, the SBA reaches or approaches the limit of its capacity to retain chloride ions. The SBA can then be regenerated, for example, by passing an aqueous solution of NaOH through a bed of SBA to return the resin to the hydroxide form. Such cycles of loading, followed by regeneration, place the resin beads under osmotic pressure because the chloride and hydroxide forms have different equilibrium water contents, and the osmotic shock of repeated cycles tends to break down some of the beads.

[0090] Similar processes of loading and regeneration can be performed with these or other resins to remove these or other ions. Weakly or strongly acidic cation exchange resins can be used to remove either monovalent or polyvalent cations. Weakly or strongly basic anion exchange resins can be used to remove unwanted monovalent and / or polyvalent anions. Any of these processes, including loading and regeneration cycles, create osmotic stress on the resin beads.

[0091] Resistance to fracture and osmotic shock makes the resins of the present invention advantageous when the intended use is water purification. Because the beads are less prone to breakage, a given collection of beads will have a longer lifespan of use before the beads need to be replaced. Also, if beads break, the fragments fill the interstitial spaces between the beads, which impede water flow through the bead bed, causing an increase in the water pressure drop from the inlet to the outlet of the bed. Broken beads can also cause channeling, which reduces the amount of water the bead bed can process, thus requiring more frequent regeneration of the beads, which in turn increases chemical costs and osmotic stress on the beads.

[0092] When the intended use of the resin is as a catalyst, the functionalized collection of polymer beads, referred to herein as a "resin," is used to produce one or more products by contacting the resin with one or more reactants and conducting a chemical reaction involving the one or more reactants. In a preferred catalyst embodiment, the collection of polymer beads is functionalized with sulfonic acid groups to produce a SAC. When used as a catalyst, the SAC is referred to as an "acid catalyst."

[0093] Resins intended for use as catalysts can be characterized by their water holding capacity (MHC). MHC is the amount of water present in a collection of polymer beads when bulk liquid water is separated from the beads and the beads reach equilibrium with air having 100% relative humidity. Preferably, the MHC of resins intended for use as catalysts is 90% or less by weight, based on the total weight of the collection of resin beads, including beads and water; more preferably, 80% or less. Preferably, the amount of water present in the resin, prior to contact with acetone and phenol, is 50% or more by weight, based on the weight of the resin; more preferably, 60% or more.

[0094] Preferred reactants are acetone and phenol, which react to form 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A). It is believed that two moles of phenol react with one mole of acetone to form one mole of bisphenol A and one mole of water. For bisphenol A formation, a preferred resin catalyst is SAC resin. The resin may or may not be reacted 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 amine and thiol groups. Preferably, the amine groups on the accelerator are bonded to sulfonic acid groups on the resin. Preferably, the mole percentage of sulfonic acid groups bonded to the amine groups of the accelerator is 5% to 50%. Preferably, water is removed from the resin bead mass before contact with acetone and phenol, for example, by rinsing with phenol. Preferably, the water content in the mass of polymeric beads immediately prior to contact with the acetone and phenol is 2% or less; more preferably 1% or less, by weight based on the mass of polymeric beads.

[0095] Preferably, the resin is at a temperature of 55°C or greater; more preferably 60°C or greater throughout the time the resin is in contact with the phenol and acetone.

[0096] Resistance to spallation is also advantageous when the intended use is catalysis: the life of the resin of the present invention will be higher, and the reduced level of fines will allow reactants to pass through the resin bed at a lower pressure drop. [Example]

[0097] The following are examples of the present invention.

[0098] The following terms, abbreviations, and ingredients were used: Jetted = Monomer oil droplets were introduced into an aqueous medium using the jetting procedure described in U.S. Pat. Nos. 4,444,960 and 4,623,706 TBC = 4-T-butylcatechol; some TBC is present in the grade of DVB used. DVB = divinylbenzene, manufactured and supplied by Dow Chemical Company. The grade of DVB used was a mixture containing 63% pure divinylbenzene and approximately 37% ethylvinylbenzene by weight. The DVB percentages listed below refer to the amount of pure DVB. When DVB is present, it is assumed that EVB is also present, at a weight ratio of EVB:DVB of approximately 37:63. The DVB contains approximately 1000 ppm TBC by weight. TBC-free DVB = DVB containing no TBC. To produce TBC-free DVB, the TBC was removed from the indicated portion of DVB by a series of 4% NaOH batch washes. CMMC = Carboxymethyl methylcellulose, manufactured and supplied by The Dow Chemical Co. PVOH = SELVOL manufactured by Sekisui Specialty Chemicals TM 523 Polyvinyl alcohol HEMC = WALOCEL manufactured by Dow Chemical Company TM MKX 15000 PF 01 Hydroxyethylcellulose SBA = Strongly basic anion exchange resin; a copolymer of styrene / DVB functionalized with quaternary ammonium groups SAC = Strong Acid Cation Exchange Resin; a styrene / DVB copolymer functionalized with sulfonic acid groups TRIS = Tris(hydroxymethyl)aminomethane, used as a 20% by weight solution in water, 100% solids supplied by Fisher Scientific PADMAC = 20 wt % solution of poly(diallyldimethylammonium chloride) in water, also known as poly(DADMAC). Gelatin = Animal gelatin, isoelectric point approximately 8.5 VPBA = 4-vinylphenylboronic acid BPO = benzoyl peroxide, 75% purity by weight DI water = deionized water Dichromate: = Sodium dichromate dihydrate solution, concentration = 70% by weight dihydrate in water GA=gradual addition Ambient temperature = approximately 23°C

[0099] Eight protocols for suspension polymerization were used, designated A, B, D, E, F, G, and H. These protocols are differentiated by the following parameters: After the copolymer beads were formed, they were functionalized using the method listed in the last column. Details of the functionalization method are given below the table.

[0100] [Table 1]

[0101] In preparing the oil droplet mixture or aqueous medium described below, some submixtures were sometimes heated above 25°C to achieve good mixing. However, when the oil droplets were formed and suspended in the aqueous medium, the components were all at ambient temperature.

[0102] When the copolymer was converted to a SAC resin, the copolymer-containing polymer beads were sulfonated by a standard sulfonation process using sulfuric acid to achieve a degree of substitution such that at least 95 mole percent of the aromatic rings on the polymerized units of the monofunctional vinyl monomer carried a sulfonate group, based on the total polymerized units of the monofunctional vinyl monomer.

[0103] Crush strength was measured as follows: Functionalized polymer beads were exposed to 100% humidity air at 50°C for 4 days. The beads were then covered with deionized water and stored at room temperature (approximately 23°C) for at least 1 hour. A single bead was placed on one plate of a room temperature compression tester, and the bead was covered with a drop of water. The plates were compressed at 6.0 mm / min until the particle fractured, and the peak force was noted. This procedure was repeated for at least 30 beads, and the average peak force was reported as the "crush strength." The tester consisted of a CHATILLON with a medium-slow motor (2.5-63.5 mm / min). TM The force tester was a model TCD 200. The force gauge was a model DFGS10. Crush strength is reported in grams of force per bead (G / BD).

[0104] Osmotic stability (OS) was measured as follows. Functionalized polymer beads were conditioned by contact with a solution of NaCl in water at ambient temperature (approximately 23°C). The NaCl solution was decanted, and the wet resin was passed through a mesh screen 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 consisted of the following: fluid was drained from the column by gravity; the resin in the column was contacted with Solution #1; the column was backwashed with water; fluid was drained from the column by gravity; the resin in the column was contacted with Solution #2; fluid was drained from the column by gravity, and the column was backwashed with water. The test was repeated 50 times. Solution #1 was H2SO4 in water. Solution #2 was NaOH in water. Cycles of exposure to different solutions caused some particles to break down. After each exposure cycle, the beads were placed on a screen that filters objects with a diameter less than 500 μm. The material retained on the screen is considered to be intact beads, and the material that passes through the screen is considered to be broken bead fragments. OS(%)=100×W 断片 / (W 無傷 +W 断片 ) and where W 断片 = weight of the fragment, W 無傷= weight of free beads. Lower OS values ​​are more desirable.

[0105] The functionalized resin samples were tested for storage stability as follows: The resin was separated from the bulk 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 in a weight ratio of 3 parts water to 1 part resin. The water was removed by filtration, and the water was tested for conductivity and absorbance at a wavelength of 350 nm using standard equipment.

[0106] In all protocols except Protocol G, the weight ratio of the oil droplet component to the aqueous phase component was 0.61:1. In Protocol G, the weight ratio of the oil droplet component to the aqueous phase component was 1:1. When DVB was added gradually during polymerization, the addition was continuous over the range of degrees shown in the table in Example R1 below. DVB addition was continuous, but the rate varied over the course of the addition.

[0107] The compositions of the starting oil droplets (just before the start of polymerization) in the following examples were as follows: Amounts are in weight percent based on the weight of the monomer oil droplets. (All samples with the same prefix used aqueous media of the same composition. For example, Examples A-2A(1), A-2A(2), and A-2B all used the same aqueous media composition, designated "A-2.") The total weight of each monomer oil droplet composition was 100%. Samples with the suffix "Comp" are used for comparison purposes. BPO was present in all starting oil droplets as an initiator.

[0108] [Table 2]

[0109] [Table 3]

[0110] The compositions of the aqueous media in the following examples were as follows: Amounts are in weight percent based on the weight of the aqueous medium. In all cases, the aqueous phase concentration of stabilizer was such that the percentage of hundreds of beads, based on the total number of beads, had a sphericity of 0.8 or greater was at least 99%. In all cases, the aqueous phase or monomer phase concentration of stabilizer was such that the percentage of hundreds of beads, based on the total number of beads, had a sphericity of 0.8 or greater was at least 99%. In all cases, the aqueous phase concentration of latex inhibitor was such that the weight percentage of emulsion polymer at the end of the reaction was less than 0.5% based on the total weight of polymer beads.

[0111] The harmonic mean diameter of the final polymer beads formed by jetting was 430-470 micrometers. For oil droplets formed by stirring, the harmonic mean diameter of the final polymer beads was 490-650 micrometers.

[0112] [Table 4]

[0113] [Table 5]

[0114] [Table 6]

[0115] Comparative Example A1-Comp (no monomer added after the start of polymerization) using Protocol A. Aqueous suspension polymerization was carried out on the reaction mixture as follows. The reaction temperature and BPO concentration combination were selected to result in 80-85% conversion within 330-390 minutes. Once the conversion to polymer was in the 80-85% range, the pH was adjusted by adding TRIS to the reactor so that the final pH was in the 8-9 range. 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 carried out.

[0116] Also using Protocol A, Examples A-2A and A-2B. Aqueous suspension polymerizations were conducted on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 390-550 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of degrees tabulated in Example R1 below, with the DVB feed rate varying with time. Two double repeat polymerizations of A-2A, designated A-2A(1) and A-2A(2), were conducted.

[0117] Once the conversion to polymer was in the 60-75% range, TRIS was added to the reactor to maintain a final pH in the range of 8-9. Within 60 minutes of the TRIS addition, the reaction 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.

[0118] Also using Protocol A, Example A-2C. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 390-550 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0119] Once the conversion to polymer was in the 60-75% range, TRIS was added to the reactor to maintain a final pH in the range of 8-9. Within 60 minutes of the TRIS addition, the reaction 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.

[0120] Comparative Example B1-Comp (no monomer added after the start of polymerization) using Protocol B. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 480-560 minutes. Once at reaction temperature, a 0.1% TBC in water feed was started to the reactor. The TBC feed rate was varied over time to simulate the TBC feed that would normally accompany a DVB feed.

[0121] TBC was gradually added from 0% to 57%. Before the start of polymerization, the TBC concentration in the monomer oil droplets was 0.0055 wt. %. At the end of the TBC feed, the TBC concentration in the monomer oil droplets (partially or completely converted to polymer) was 0.0101 wt. %.

[0122] Once the conversion to polymer reached 80-85% the pH was adjusted by adding TRIS to the reactor so that the final pH was 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.

[0123] Similarly using Protocol B, Examples B-2A, B-2B, B-2C, B-2D, B-2E, and B-2F. Duplicate samples of B-2B were prepared, designated B-2B(1) and B-2B(2).

[0124] Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 420-600 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0125] Once the conversion to polymer was in the range of 60-85%, TRIS was added to the reactor to maintain a final pH in the range of 8-9. Within 60 minutes of the TRIS addition, the reaction 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.

[0126] Comparative Example C1-Comp (no monomer added after initiation of polymerization) using Protocol C. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 330-390 minutes. Once the reaction temperature was reached, TRIS was added to the reactor so that the final aqueous pH was in 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.

[0127] Example C-2, using Protocol C. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 420-600 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0128] Once the conversion reached the 60-85% range, TRIS was added to the reactor to maintain a final pH in the range of 8-9. Within 60 minutes of the TRIS addition, 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.

[0129] Comparative Example D1-Comp (no monomer added after initiation of polymerization) using Protocol D. Aqueous suspension polymerization was carried out on the reaction mixture as follows. The reaction temperature and BPO concentration combination were selected to result in 80-85% conversion within 420-600 minutes. Once the conversion to polymer was in the 80-85% range, the pH was adjusted by adding TRIS to the reactor so that the final pH was in the 8-9 range. 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 carried out.

[0130] Using Protocol D, Example D-2A. Aqueous suspension polymerizations were carried out on the reaction mixture as follows. A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 390-550 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of degrees shown in the table in Example R1 below, with the DVB feed rate varying with time. Two double repeat polymerizations, designated D-2A(1) and D-2A(2), were carried out.

[0131] As soon as the conversion to polymer reached 20-30% TRIS buffer was added to the reactor to maintain a final pH in the range of 8-9. When the conversion reached 80-85%, additional TRIS buffer was added to maintain a final pH in the range of 8-9. Within 60 minutes of the TRIS addition, the reaction was then heated to 97°C. After 1 hour, the reaction was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0132] Example D-2B Using Protocol D. The same protocol as in D-2A was used, except that DVB was added gradually over the range of levels tabulated in Example R1 below. Two double repeat polymerizations, designated D-2B(1) and D-2B(2), were performed.

[0133] Comparative Example E1-Comp (no monomer added after the start of polymerization) using Protocol E. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 210-270 minutes. Once the conversion to polymer was in the 80-85% range, the reaction 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.

[0134] Example E-2, using Protocol E. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 300-360 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0135] Once the conversion to polymer was in the 80-85% range, the reaction was heated to 92° C. After 1 hour, the reaction was cooled to ambient temperature and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0136] Comparative Example F1-Comp (no monomer added after initiation of polymerization) using Protocol F. Aqueous suspension polymerization was carried out on the reaction mixture as follows. The reaction temperature and BPO concentration were selected to achieve 80-85% conversion within 300-360 minutes. Once the conversion to polymer was in the 80-85% range, the pH was adjusted by adding TRIS to the reactor so that the final pH was in the 8-9 range. 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.

[0137] Example F-2, using Protocol F. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 330-390 minutes. Once the reaction temperature was reached, TBC-free DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0138] Once the conversion to polymer was in the 80-85% range, TRIS was added to the reactor to maintain a final pH in the 8-9 range. Within 60 minutes of the TRIS addition, the reaction 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.

[0139] Comparative Example G1-Comp (no monomer added after the start of polymerization) using Protocol G. Aqueous suspension polymerization was carried out on the reaction mixture as follows: The reaction temperature and BPO concentration combination were selected to result in 80-85% conversion within 300-360 minutes. Once the conversion to polymer was in the 80-85% range, the reaction was heated to 90°C. After 3 hours, the reaction was cooled to ambient temperature, and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0140] Example G-2 using Protocol G. Aqueous suspension polymerization was carried out on the reaction mixture as follows: A combination of reaction temperature and BPO concentration was selected to result in 80-85% conversion within 420-600 minutes. Once the reaction temperature was reached, DVB was fed to the reactor over the range of levels tabulated in Example R1 below, with the DVB feed rate varying with time.

[0141] Once the conversion to polymer was in the 80-85% range, the reaction was heated to 90 C. After 3 hours, the reaction was cooled to ambient temperature and the beads were dehydrated, washed with water, and dried at ambient temperature.

[0142] Example R1: Physical Stability Test Results of SAC Resin The copolymers prepared by the above protocol were converted to SAC resins and tested as described above. The results were as follows: Where duplicate samples were tested, the average results are shown. Method = Whether the polymerization method had a gradual addition (GA) step of the present invention. Initial DVB = amount of DVB in the monomer droplet before the start of polymerization (by weight based on the weight of the monomer droplet) Final DVB = the amount of polymerized units of DVB in the finished polymer, by weight based on the total weight of all monomers used in the entire process, including the initial oil droplets and the DVB fed during polymerization. EXTSTART = reaction progress at the time DVB supply started EXTSTOP = reaction progress at the end of DVB supply DIAM = harmonic mean diameter of polymer beads

[0143] [Table 7]

[0144] [Table 8]

[0145] Example R2: Results of Testing Protocol E Samples Strongly basic anion (SBA) exchange resins were prepared from the copolymer of Protocol E by the standard method of chloromethylation using chloromethyl ether, followed by amination using trimethylamine, so that at least 95 mole percent of the polymerized units of the monofunctional vinyl monomer had an aromatic ring-attached amine-containing group on the polymerized units of the monofunctional vinyl monomer, based on the total polymerized units of the monofunctional vinyl monomer.

[0146] The SBA resin was tested as in Examples A through R. The results were as follows:

[0147] [Table 9]

[0148] Example R3: Catalytic Reaction Results Various functionalized resin samples were tested for their activity in catalyzing the reaction between phenol and acetone to produce bisphenol-A (BPA). Catalytic activity is characterized by the time to 60% conversion ("T60%"). Shorter times reflect higher levels of catalytic activity.

[0149] The catalysis reaction was carried out as follows: The resin was rinsed with phenol to remove moisture from the beads. The phenol was added to a glass reactor and heated to 50°C to melt the phenol. The accelerator-loaded, dry resin was added to the reactor and allowed to swell in the phenol. The reactor temperature was adjusted to a temperature between 45°C and 80°C. Acetone was added to the reactor. At timed intervals, small samples of the liquid in the reactor were pipetted, placed in vials, and mixed with excess N-methyl-N-(trimethylsilyl)trifluoroacetamide. The vials were stored at 60°C for 30 minutes, then cooled to ambient temperature and tested by gas chromatography for BPA content.

[0150] The catalytic results were as follows: All of the samples shown had a total amount of polymerized units of DVB of 4.65%.

[0151] [Table 10]

[0152] Samples A-2A, A-2B, and A-2C, which were made using gradual addition according to the present invention, had much shorter times to 60% conversion than the comparative samples.

[0153] Example R4: Results of 30 days of storage at ambient temperature The storage results were as follows:

[0154] [Table 11]

[0155] Each example resin exhibited lower conductivity and absorbance than its corresponding comparative example. That is, Samples A-2A and A-2B exhibited lower conductivity and absorbance than Comparative A-1Comp. Similarly, Sample C-2 exhibited lower conductivity and absorbance than Comparative C-1Comp. This result indicates that the resins of this example have greater stability during storage.

Claims

1. A collection of polymer beads, said beads comprising: (i) 75 to 99 weight percent of polymerized units of a monofunctional vinyl monomer, based on the weight of the beads; (ii) 1 to 25% by weight of polymerized units of a polyfunctional vinyl monomer, based on the weight of the beads; Including, Within each bead, the average concentration of moles of polymerized units of the multifunctional vinyl monomer per cubic micrometer is MVAV; Within each bead, T1000 is a sequence of 1,000 unique linked polymerized monomer units; Within each T1000, MVSEQ is the weight percent polymerized units of the multifunctional vinyl monomer, based on the weight of the T1000; MVRATIO = MVSEQ / MVAV; and 90% or more of the beads by volume are uniform beads (wherein uniform beads are beads in which 90% or more of all T1000 sequences have an MVRATIO of 1.5 or less). Collectibles.

2. 10. The collection of polymeric beads of claim 1, wherein in 90% or more of the beads by volume, 90% or more of all T1000 sequences have an MVRATIO of 1.25 or less.

3. 10. The collection of polymer beads of claim 1, wherein the monofunctional monomer comprises styrene.

4. 10. The collection of polymer beads of claim 1, wherein the multifunctional vinyl monomer comprises divinylbenzene.

5. 10. The collection of polymer beads of claim 1, wherein no more than 35% of the T1000 sequences have an MVRATIO of 0.5 or less.

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