DE2827475C2 - - Google Patents

Description

The invention relates to the production of polymer beads, which prove to be excellent ion exchange polymer beads physical properties.

The methods of making cross-linked vinyl copolymers in spherical form (as a precursor for ion exchange resins) free radical catalyzed polymerization of the Monomer mixture in aqueous dispersion is known. Under the term "cross-linked vinyl copolymer" or the like Copolymers from a larger proportion, i. H. 50 to 99.5 mol% and preferably 80 to 99% of a monoethylenically unsaturated Monomers, for example a monoethylenically unsaturated one aromatic monomers, such as styrene, vinyl toluene, Vinyl naphthalene, ethyl vinyl benzene, vinyl chlorobenzene and Chloromethylstyrene, also esters of acrylic acid and methacrylic acid, such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, Butyl acrylate, tert-butyl acrylate, ethylhexyl acrylate, Cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate, Phenyl acrylate, alkylphenyl acrylate, ethoxymethyl acrylate, ethoxypropyl acrylate, Propoxypropyl acrylate, ethoxyphenyl acrylate, Äthoxybenzylacrylat or Äthoxycyclohexylacrylat, and the corresponding esters of methacrylic acid, with a smaller one Amount, d. H. 0.5 to 50 mol% and preferably 1 to 20%, polyethylenically unsaturated monomers with at least two active ethylenically unsaturated groups with the above mentioned monounsaturated monomers with formation crosslinked insoluble and infusible copolymer polymerizable are understood, the latter of which Compounds, for example, the following may be mentioned: divinylbenzene, Trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, Divinyltoluene, trivinylbenzene, divinylchlorobenzene, Diallyl phthalate, divinyl pyridine, divinyl naphthalene, ethylene glycol diacrylate, Neopentyl glycol dimethacrylate, diethylene glycol divinyl ether, Bisphenol A dimethacrylate, pentaerythritol tetra and trimethyl acrylate, divinyl xylene, divinyl ethyl benzene, Divinyl sulfone, divinyl ketone, divinyl sulfide, allyl acrylate,  Dialalymaleate, diallyl fumarate, diallyl succinate, diallyl carbonate, Diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, Divinyl sebacate, diallyl tartrate, diallyl silicate, Triallyl tricarballylate, triallylaconitat, triallyl citrate, Triallyl phosphate, N, N'-methylenediacrylamide, N, N'-methylenedimethacrylamide, N, N′-ethylenediacrylamide, trivinylnaphthalene, Polyvinylanthracenes as well as the polyallyl and polyvinyl ethers of glycol, glycerin, pentaerythritol, resorcinol and the mono- and dithio derivatives of glycols.

The copolymer can also be polymerized up to about 5 mole percent Units of other ethylenically unsaturated monomers contain that do not affect the basic nature of the resin matrix, for example methyl acrylate, acrylonitrile and butadiene.

Conventional polymerization conditions lead to cross-linked Vinyl copolymers used in the conversion to ion exchange resins determined by linking functional groups show procedural disadvantages, which refer to physical Weaknesses are due.

The object of the invention is a method for the production of cross-linked discrete copolymer beads to create that have high mechanical strength and are resistant to osmotic shocks.

This object is achieved by the method of claim 1 solved.

Those produced by the process according to the invention Copolymer beads have high mechanical strength against the influence of external forces, for example due to the weight of a resin column bed, strong fluid flow as well as a backwash. Ion exchange resins, those using the manufactured according to the invention  Copolymer spheres are therefore special suitable for the treatment of liquid streams with high flow velocities, such as those used for Clean condensates occur, with poorer resins Quality to a mechanical breakdown and tend to have short lifespans.

The invention is based on the finding that a special Group of peroxy catalysts, of which it was previously unknown that they have advantages in the manufacture of ion exchange polymers conditioned, used to produce a polymer can be the corresponding after functionalization conventional materials unexpectedly is superior. The catalysts that offer these advantages can generally be used as peroxyesters and peroxydicarbonates characterize.

In DE-OS 28 05 121.0 and 28 20 947.4 an improvement the ion exchange resin quality described in such a way that the oxygen content of the monomer mixture is controlled during the polymerization and / or a "Reaction modifier" is added to the monomer mixture.

DE-PS 9 74 216 describes the use of a "peroxide catalyst" in networking systems and FR-PS 15 11 374 discloses the use of certain peroxide catalysts the production of styrene homopolymers. None of these references but describes the specific peroxide catalysts, as mentioned in claim 1, and the fact that cross-linked copolymers are produced using them can, both in terms of Chatillon values as well  the number of intact beads excellent results deliver how the related attempts in the application documents show and are essential for the production of good ion exchange resins.

The peroxyester catalysts used according to the invention are commercially available and are used for vinyl polymerization recommended.

Suitable peroxydicarbonate catalysts to carry out of the invention are those that are under the following formula fall:

where Y and Z are the same or different and lower (C₁-C₈ and preferably C₁-C₄) alkyl, cycloalkyl, alkyl-substituted Are cycloalkyl or aralkyl. Such materials are owned by the Lucidol Division, Pennwalt Corporation under the name "Lupersol" and from Noury Chemical Corporation under the name "Percadox" brought.

A preferred group of peroxy ester catalysts are tert-butyl peroctoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy isobutyrate, tert-butyl peroxy neodecanoate, tert-amyl peroctoate and 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane.

A preferred group of peroxydicarbonate catalysts includes di (4-tert-butylcyclohexyl) peroxydicarbonate, di (sec-butyl) peroxydicarbonate, Di (2-ethylhexyl) peroxydicarbonate, Dicetyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.  

To carry out the invention, the vinyl monomer, the crosslinking monomer and optionally another Monomer are polymerized in an aqueous dispersion, which the peroxy catalyst (optionally as "free radicals delivering initiator ") and, if desired, Oxygen and / or a "reaction modifier", as described in the DE-OS specified above will contain. Generally about 0.1 to about 2.0% of the peroxy catalyst based on that Weight of the monomer mixture used. The invention Polymerization methods generally do not differ the known methods for the production of ion exchange polymers and resins.

The polymerization is usually at a temperature from 30 to 90 ° C and preferably 45 to 80 ° C and in particular 50 to 75 ° C performed. According to a preferred embodiment it is advisable to lower reaction temperatures to adhere to during the initial stages of polymerization, d. H. to at least about 50%, and preferably at least 75% of the monomer in the dispersion have reacted. During the final stages of the polymerization, the temperature expediently at 20 to 30 ° C above the temperature increased that adhered to during the initial stages becomes. It is possible at temperatures from 15 to 35 ° C below of temperatures to work as they normally do the known methods are followed. Will at deeper Temperatures, for example 30 to 60 ° C, using the catalysts (percadox type) worked, then it may be useful to use a second so-called "chaser catalyst" to use the active at higher temperatures is, for example at temperatures from 75 to 100 ° C, by higher  To achieve yields of cross-linked vinyl polymer, wherein for example 0.05 to 0.1%, based on the monomer weight, initiators such as benzoyl peroxide, tert-butyl peroctoate as well as tert-butyl peroxy isobutyrate will.

The aqueous medium in which the polymerization is in dispersion form usually contains smaller amounts on conventional suspension additives, i.e. H. Dispersants, such as xanthan gum (biosynthetic polysaccharide), poly (diallyldimethylammonium chloride), polyacrylic acid (and salts), Polyacrylamide, magnesium silicate and hydrolyzed poly- (styrene / maleic anhydride), also protective colloids, such as Carboxymethyl cellulose, hydroxyalkyl cellulose, methyl cellulose, Polyvinyl alcohol, gelatin and alginates, buffering aids, such as phosphate and borate salts, and pH-controlling Chemicals such as sodium hydroxide and sodium carbonate.

The high molecular weight crosslinked copolymers can from the reaction vessel in the form of hard discrete Beads with a particle size of 0.02 to 2 mm, usually with a particle size of 0.2 to 1 mm will. These copolymers can be used in ion exchange resins be converted in such a way that functional groups be tied up by conventional methods, whereby from Such functional groups include the following: Sulfonamide, trialkylamino, tetralkylammonium, carboxyl, Carboxylate, sulfonic acid, sulfonate, hydroxyalkylammonium, Iminodiacetate, amine oxide, phosphonate and other known ones Groups. The functionalization reactions that are used of vinyl aromatic copolymers for the production of Ion exchange resins can be carried out  for example from a sulfonation with concentrated Sulfuric acid, chlorosulfonation with chlorosulfonic acid and subsequent amination, reaction with sulfuryl chloride or thionyl chloride and subsequent amination and Chloromethylation and subsequent amination. Typical Functionalization reactions on (vinyl) acrylic copolymers are hydrolysis to acrylic acid resins, amidolysis as well as a transesterification. Ion exchange resins can also can be classified as follows: strong acidic cation resins, for example resins which have the sulfonic acid group (-SO₃H group) or sulfonate group (-SO₃M group, where M usually is an alkali metal ion), weakly acidic Cation exchange resins, for example resins which the Carboxyl group (CO₂H) or carboxylate group (-CO₂M, where M is usually an alkali metal ion), strongly basic Anion exchange resins, for example resins, which contain a tetraalkylammonium NR₃X group, where R is an alkyl or is hydroxyalkyl group and X is usually chloride or Means hydroxide, as well as weakly basic anion exchange resins, for example, resins that have a trialkylamino group -NR₂ contain, where R is an alkyl or hydroxyalkyl group is.

The properties of the resins produced according to the invention only become apparent when the crosslinked copolymers in ion exchange resins by linking functional ones Groups are converted. The physical strength These ion exchange resins are based on their resistance against crushing, which in conventional Way using the Chatillon instrument ("Osmotical and Mechanical Strength of Ion Exchange Resins" by L. S. Goldon and J. Irving in "Chemistry and Industry (London), volume 21, pages 837 to 844 (1972)) will, furthermore by visual examination before and after use as an ion exchanger. For example, you can  strongly acidic styrene resins according to the preferred one according to the invention Method be made in such a way that they Have chatillon values of 1000 to 5000 g (force per bead), compared to resins based on copolymers decline, which are produced by known polymerization methods which are Chatillon values in a conventional manner from 50 to 500 g / pellet. In a similar way can be strongly basic styrenic resins according to the present Invention Chatillon values from approximately 500 to 1500, in comparison to known resins, which often have chatillon values own from 25 to 400.

The following examples illustrate some preferred embodiments the invention.

example 1

The polymerization reactor is a 2 liter three-necked round bottom flask, the one with a two-blade stirrer, thermometer, cooler, heating jacket with temperature control device and a device is provided with an inert gas for purging. In these A reactor mixture is poured out of the reactor 500.4 g styrene and 85.6 g divinylbenzene and 1.9 g tert-butyl peroctoate exists. The headspace is filled with nitrogen rinsed and then added the aqueous phase, namely 510 g water, 20.1 g poly (diallyldimethylammonium chloride) as a dispersant, 1.6 g gelatin as a protective colloid, 0.88 g boric acid and such an amount of 50% Sodium hydroxide solution sufficient to maintain a pH between 10.0 and 10.5. The stirrer is started whereupon the reaction mixture at room temperature to 75 ° C  heated for a period of 45 minutes and during this Temperature held for a period of 4.0 hours becomes. Then the polymerization in the Way ended that the reaction mixture at 95 ° C during lasts for a period of 1 hour. The copolymer beads are separated, washed and for functionalization prepared.

In this as well as in the following examples, strongly acidic Resins from the copolymer can be optionally used according to the following Methods made:

Sulfonation A

A portion of the copolymer beads prepared above (110 g) becomes 600 g of a 95% H₂SO₄ in a 1 liter flask given that with a stirrer, cooler, dropping funnel, Provide thermometer, alkali washer and a heater is. 39 g ethylene dichloride (ball soothing agent) are added, whereupon the suspension at 30 to 130 ° C. is heated for a period of 3 hours. Then there is a hydration in which water is added, to deter the product. The sulfonated product will then washed to remove residual acid. The physical Properties of the strongly acidic resin product come from the following Table I.

Sulfonation B

A portion of the beads (50 g) prepared according to Example 1 is added to 315 g of 94% H₂SO₄ in a 1 liter flask, with a stirrer, cooler, dropping funnel, thermometer, Alkali washer and a heater is provided.  30 g of ethylene dichloride (ball soothing agent) are added, whereupon the suspension is heated to 60 to 65 ° C. and on maintained at this temperature for a period of 1 hour becomes. The mixture is then heated to 115 ° C and on this value is held for a period of 4 hours. This is followed by a hydration stage, during which Water is added to quench the product. The sulfonated product is then used to remove residual acid washed.

Of the first eighteen specific examples given in the case of Examples 1, 2, 4 to 7 and 11 to 18 functionalizes the copolymer products according to the sulfonation method "A", while the functionalization in the case of the rest Examples are carried out according to the sulfonation method "B".

Example 2

Using the procedure described in Example 1 is a copolymer ion exchange resin precursor from identical Starting materials manufactured in identical quantities. The Properties of the product after sulfonation go out Table I below.

Example 3

According to the procedure described in Example 1 254.5 g styrene, 42.4 g divinylbenzene, 3.0 g methyl acrylate and 1.5 g of tert-butyl peroctoate are introduced into the reaction vessel. The aqueous phase consists of 270 g H₂O, 10.0 g poly (diallyl dimethylammonium chloride), 0.8 g gelatin as protective colloid, 0.45 g boric acid and a 50% NaOH solution in one an amount sufficient to adjust the pH between 10.0 and To hold 10.5. The reaction mixture is kept at 75 ° C during heated for a period of 2.7 hours and then during a kept at 95 ° C for another hour. The product is washed and sulfonated. The properties of the resin go out  Table I below.

Example 4

According to the method described in Example 1, 491.7 g Styrene, 85.5 g divinylbenzene, 8.8 g methyl acrylate, 0.51 g Methylcyclopentadiene dimer and 1.90 g of tert-butyl peroctoate filled into the reaction vessel. The aqueous phase consists of 510.0 g H₂O, 20.1 g poly (diallyldimethylammonium chloride), 1.6 g gelatin as protective colloid, 0.83 g boric acid and 50% NaOH solution in such an amount as necessary sufficient to keep the pH between 10.0 and 10.5. The reaction mixture is at 75 ° C for a period of 4 hours and then to 95 ° C for a period of one heated for another hour. The product is washed and sulfonated. The properties of the resin follow from the following Table I.

Example 5

According to the procedure described in Example 1 491.7 g styrene, 85.5 g divinylbenzene, 8.8 g methyl acrylate, 0.59 g of methylcyclopentadiene dimer and 1.90 g of tert-butyl peroctoate filled into the reaction vessel. The aqueous phase consists of 510.0 g H₂O, 20.1 g poly (diallyldimethylammonium chloride), 1.6 g gelatin as protective colloid, 0.88 g Boric acid and such an amount of a 50% NaOH solution, that the pH is maintained between 10.0 and 10.5. The Reaction mixture is kept at 75 ° C over a period of 4 hours and heated to 95 ° C for an additional hour. The product is washed and sulfonated. The properties of the resin are shown in Table I below.

Example 6

According to the procedure described in Example 5, wherein the same organic and aqueous phases are used  a resin is prepared that the specified in Table I. Possesses properties.

Example 7

According to the procedure described in Example 1, but using 0.59 g of the reaction modifier α- methylstyrene dimer and using tert-butyl peroctoate as the initiator in an amount of 1.9 g, a resin with the properties given in Table I is used produced.

Example 8

According to the procedure described in Example 1, wherein however 3.0 g of methyl acrylate, 1.5 g of tert-butyl peroctoate and 0.3 g of cycloheptatriene (reaction modifier) used will be a resin with the specified in Table I. Properties manufactured.

Example 9

According to the general procedure described in Example 1, however, 3.0 g of methyl acrylate, 1.5 g of tert-butyl peroctoate, 0.3 g norbornene (reaction modifier) used, a resin is produced, which in the Table I has properties specified.

Example 10

According to the procedure described in Example 1, however 3.0 g of methyl acrylate, 1.5 g of tert-butyl peroctoate and 0.3 g Dicyclopentadiene (reaction modifier) used a resin is produced that the in Table I has the specified properties.  

Example 11

According to the procedure described in Example 1, wherein however, 8.8 g of methyl acrylate, 0.29 g of methylcyclopentadiene dimer (Reaction modifier) and 2.64 g of di (4-tert.- butylcyclohexyl) peroxydicarbonate (Percodox 16 - T. M.) used will be a resin with the specified in Table I. Properties manufactured. A protective sheath 8% O₂ in N₂ is over the reaction mixture during a Rinse time of 30 minutes. Furthermore, 0.59 g Sodium nitrite in the aqueous phase used to make a To prevent polymerization (likewise in the examples 12 and 13).

Example 12

According to the procedure described in Example 1, wherein however, 8.8 g of methyl acrylate, 0.29 g of methylcyclopentadiene dimer and 2.64 g of di (4-tert-butylcyclohexyl) peroxydicarbonate (Initiator) can be used in the organic phase a resin is made. The initial polymerization is carried out at 57 ° C for a period of 7 hours, whereupon the temperature rose to 95 ° C over a period of time is increased by 1 hour. The properties of the resin appear from Table I.

Example 13

According to the procedure described in Example 1, wherein however, 8.8 g of methyl acrylate and 2.64 g of di- (4-tert-butyl cyclohexyl) peroxydicarbonate (but not a reaction modifier) is used and a reaction temperature of 56 ° C over a 7 hour period and 75 ° C during is observed within a period of 2 hours a resin with the properties given in Table I. produced.  

Example 14

According to the procedure described in Example 1, wherein however, 1.9 g of 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane (Initiator) is used and a reaction temperature of 70 ° C for a period of 4 hours and then 90 ° C for a period of 1 hour is observed, a resin with the in Table I specified properties manufactured.

Example 15

According to the procedure described in Example 1, wherein however 1.12 g of tert-butyl peroxyneodecanoate (initiator) is used and an initial reaction temperature of 53 to 54 ° C for a period of 4.5 hours and 70 ° C maintained for a period of 1 hour becomes a resin with the specified in Table I. Properties manufactured.

The following examples explain the known production methods as well as products that are preserved.

Comparative Example 16

According to the procedure described in Example 1, wherein 2.20 g of benzoyl peroxide (initiator) are used and an initial reaction temperature of 75 ° C over a period of time of 4 hours and a final temperature of 95 ° C during is observed within a period of 1 hour Resin produced with the properties specified in Table I.

Comparative Examples 17 and 18

Example 16 is repeated twice. The received Products have the properties specified in Table I.  

The resins prepared according to the previous examples are used to determine the percentage of total Beads (% WB), the percentage of the perfect Form present pellet (% PB), the bursting strength the beads (Chatillon test method) and for the determination the reduction in the percentage of perfectly present Beads after repeated cycle treatments in acidic and basic solutions (accelerated use test) tested. All tests are performed on the resin after sulfonation.  

Table I

Physical resin properties

Weak as well as strongly basic resins with improved ones Properties can also be produced according to the invention be, the known methods for post-functionalization of the copolymer resins to produce weak ones or strong anion exchange groups instead of the above described sulfonation method can be applied. A preferred known method for functionalization with anion exchange groups sees a chloromethylation and subsequent amination.

Examples 19 to 20

Two strongly basic styrene / divinylbenzene resins are used the general described in Example 1 for the copolymer Method prepared using a conventional chloromethylation / amination method for functionalization of the copolymer is applied. In the case of the copolymer Example 19 uses terpinolene as a reaction modifier and 2,6-dimethyl-2,4,6-octatriene in the case of Example 20 used. In the case of both copolymers tert-butyl peroctoate used as an initiator. A comparative sample one of the strongly basic commercially available Resin made without a reaction modifier is, using a known initiator made for comparison. The characteristics of the Resins produced are shown in Table II.

Table II

Properties of strongly basic resins

The acid / base cycle test is carried out with 1N HCl and 0.5N NaOH at room temperature for a period of 100 cycles at about 2 cycles / hour.

Claims (4)

1. A process for the preparation of hard crosslinked, discrete copolymer beads by free radical polymerization in an aqueous dispersion of a monomer mixture of 50 to 99.5 mol% of a monoethylenically unsaturated aromatic monomer or ester of acrylic acid and methacrylic acid on the one hand and 0.5 to 50 Mol% of a crosslinking monomer with at least two active ethylenically unsaturated groups on the other hand, characterized in that the polymerization in the presence of one or more peroxy catalysts of the formula wherein R₁ is branched alkyl having 3 to 12 carbon atoms and has a secondary or tertiary carbon atom linked to the carbonyl group and x is 1 or 2, and when x is 1, R₂ is a branched alkyl group which is a has tertiary carbon atom associated with the oxygen, and when x is 2, R₂ is an alkylene or aralkylene group, in any case ending in tertiary carbon atoms linked to the oxygen, or of the formula is carried out, where Y and Z are the same or different and are lower alkyl, cycloalkyl, alkyl-substituted cycloalkyl or aralkyl. 2. The method according to claim 1, characterized in that the peroxy catalyst used from tert-butyl peroctoate, tert-butyl peroxyneodecanoate, 2,5-dimethyl-2,5-bis- (2-ethylhexanoylperoxy) hexane, di (4-tert-butylcyclohexyl) - peroxydicarbonate and / or dicyclohexylperoxydicarbonate consists. 3. The method according to claim 1 or 2, characterized in that the polymerization is carried out in the presence of oxygen which is in contact with the monomer mixture and / or is dissolved therein, the polymerization is carried out until the gelation point is reached has been.   4. Use of the produced according to claims 1 to 3 Copolymer beads for the production of ion exchangers.