U.S. patent application number 14/867394 was filed with the patent office on 2016-03-17 for process for the preparation of monodisperse polymer particles.
The applicant listed for this patent is Arvid BERGE, LIFE TECHNOLOGIES AS, Viola Ugelstad. Invention is credited to Elin Marie AKSNES, Oddvar AUNE, Arvid BERGE, John BJORGUM, Turid ELLINGSEN, Geir FONNUM, Finn HANSEN, Arne JORGEDAL, Astrid MOLTEBERG, Rolf NORDAL, Silje NORDBO, Henning PETTERSEN, Solveig STAALE, Tollef T ARNEBY, John UGELSTAD, Ellen WENG.
Application Number | 20160075800 14/867394 |
Document ID | / |
Family ID | 26243944 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160075800 |
Kind Code |
A1 |
JORGEDAL; Arne ; et
al. |
March 17, 2016 |
PROCESS FOR THE PREPARATION OF MONODISPERSE POLYMER PARTICLES
Abstract
A process for the preparation of monodisperse polymer particles
which are formed by contacting monomers with aqueous dispersions
comprising monodisperse swellable seed polymers/oligomers, and
initiating polymerization in the presence of a steric stabilizer.
The resulting swollen seed particles are characterized by the
particle mode diameter.
Inventors: |
JORGEDAL; Arne; (Raelingen,
NO) ; AKSNES; Elin Marie; (Oslo, NO) ; FONNUM;
Geir; (Fjellhamar, NO) ; MOLTEBERG; Astrid;
(Fetsund, NO) ; NORDAL; Rolf; (Skedsmokorset,
NO) ; PETTERSEN; Henning; (Lillestrom, NO) ; T
ARNEBY; Tollef; (Auli, NO) ; STAALE; Solveig;
(Rasta, NO) ; WENG; Ellen; (Oppegaard, NO)
; HANSEN; Finn; (Strommen, NO) ; NORDBO;
Silje; (Oslo, NO) ; AUNE; Oddvar; (Tiller,
NO) ; BERGE; Arvid; (Trondheim, NO) ; BJORGUM;
John; (Heimdal, NO) ; ELLINGSEN; Turid;
(US) ; UGELSTAD; John; (US) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BERGE; Arvid
Ugelstad; Viola
LIFE TECHNOLOGIES AS |
Trondheim
Carlsbad |
CA |
US
NO
US |
|
|
Family ID: |
26243944 |
Appl. No.: |
14/867394 |
Filed: |
September 28, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14152793 |
Jan 10, 2014 |
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14867394 |
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13649045 |
Oct 10, 2012 |
8658733 |
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14152793 |
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12644003 |
Dec 21, 2009 |
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13649045 |
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11747860 |
May 11, 2007 |
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12644003 |
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09958431 |
Oct 9, 2001 |
7217762 |
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PCT/GB2000/001334 |
Apr 10, 2000 |
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11747860 |
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Current U.S.
Class: |
521/56 ; 524/156;
524/529; 524/733 |
Current CPC
Class: |
C08J 9/16 20130101; C08F
291/00 20130101; C08F 265/04 20130101; C08J 9/224 20130101; C08J
2203/14 20130101; C08J 2325/06 20130101; C08F 265/10 20130101; C08J
9/22 20130101; C08J 2347/00 20130101; C08F 2/22 20130101; C08F
257/02 20130101 |
International
Class: |
C08F 2/22 20060101
C08F002/22; C08J 9/22 20060101 C08J009/22 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 1999 |
GB |
9908163.0 |
Mar 22, 2000 |
GB |
0007008.6 |
Claims
1. A process for the preparation of monodisperse polymer particles
having diameters of 1.mu. to 6.mu., the process comprising: forming
an aqueous dispersion comprising monodisperse swellable seed
particles and an anionic surfactant; contacting the aqueous
dispersion with a monomer selected from the group consisting of
acrylic monomers, methacrylate monomers and vinyl monomers selected
from the group consisting of styrene, divinylbenzene (DVB), ethyl
vinyl benzene, vinyl pyridine, aminostyrene, methyl-styrene,
dimethylstyrene, ethyl styrene, ethyl-methyl-styrene,
p-chlorostyrene and 2,4-dichlorostyrene; allowing the monomer to
diffuse into the seed particles to form an aqueous dispersion of
swollen seed particles; and initiating polymerization of the
monomer in the aqueous dispersion of swollen seed particles;
wherein the aqueous dispersion of swollen seed particles further
comprises a polyvinylpyrrolidone.
2. The process of claim 1, wherein the polyvinylpyrrolidone has an
average molecular weight of 10 kD to 2000 kD.
3. The process of claim 1, wherein the monodisperse swellable seed
particles are monodisperse swellable seed oligomer particles.
4. The process of claim 1, wherein the monomer comprises at least
30% by weight divinyl benzene.
5. The process of claim 1, wherein the anionic surfactant is sodium
dodecyl sulfate.
6. A process for the preparation of monodisperse polymer particles,
the process comprising: forming an aqueous dispersion comprising
monodisperse swellable seed particles and an anionic surfactant;
contacting the aqueous dispersion of seed particles with a monomer;
allowing the monomer to diffuse into the seed particles to form an
aqueous dispersion of swollen seed particles having a mode diameter
of 5.mu. to 200.mu.; and initiating polymerization of the monomer
in the aqueous dispersion of swollen seed particles; wherein the
aqueous dispersion of swollen seed particles further comprises a
water soluble cellulose ether of weight average molecular weight 10
kD to 100 kD.
7. The process of claim 6, wherein the water soluble cellulose
ether is a hydroxy propylmethyl cellulose.
8. The process of claim 6, wherein the monomer comprises at least
30% by weight divinyl benzene.
9. The process of claim 6, wherein the anionic surfactant is sodium
dodecyl sulfate.
10. A process for the preparation of monodisperse polymer particles
having a diameter of at least 16.mu., the process comprising:
forming an aqueous dispersion comprising monodisperse swellable
seed particles and an anionic surfactant; contacting the aqueous
dispersion of seed particles with a monomer; allowing the monomer
to diffuse into the seed particles to form an aqueous dispersion of
swollen seed particles; and initiating polymerization of the
monomer in the aqueous dispersion of swollen seed particles to
produce a polymer; wherein the swollen seed particles contain at
least two porogens, at least one of which is a solvent for the
polymer produced and at least one of which is not a solvent for the
polymer produced, and at least one porogen is an aliphatic
hydrocarbon having up to 12 carbon atoms.
11. The process of claim 10, wherein the porogens comprise toluene
and n-heptane.
12. The process of claim 10, wherein the aqueous dispersion of
swollen seed particles further comprises a water soluble cellulose
ether or a polyvinylpyrrolidone.
13. The process of claim 10, wherein the aqueous dispersion
comprises droplets comprising an organic compound with a molecular
weight below 5000 Dalton and a water solubility at 25.degree. C. of
less than 10-.sup.2 g/L.
14. The process of claim 10, wherein the aqueous dispersion
comprises an organic solvent.
15. The process of claim 10, wherein the aqueous dispersion
comprises dioctanoyl peroxide.
16. The process of claim 10, wherein the monomer comprises at least
30% by weight divinyl benzene.
17. The process of claim 10, wherein the anionic surfactant is
sodium dodecyl sulfate.
18.-22. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of co-pending U.S.
patent application Ser. No. 09/958,431, filed Oct. 9, 2001, which
is a national stage filing under 35 U.S.C. 371 of PCT/GB00/01334,
filed Apr. 10, 2000, which claims priority to GB9908163.0, filed
Apr. 9, 1999 and GB0007008.6, filed Mar. 22, 2000.
FIELD OF THE INVENTION
[0002] This invention relates to improvements in and relating to
the preparation of substantially monodisperse polymer
particles.
DESCRIPTION OF RELATED ART
[0003] Monodisperse polymer particles (i.e. particles with a
coefficient of variation of less than 10%, preferably less than 5%
and more preferably less than 3%) have been commercially available
for several years and find applications in many technical fields,
e.g. in pharmaceuticals, in separation processes, as toners, as
filters, as spacers, etc.
[0004] Polymer beads may be produced by diffusing a monomer and a
polymerization initiator (or catalyst) into polymer seeds in an
aqueous dispersion. The seeds swell and following initiation of
polymerization, e-g. by heating to activate the initiator, larger
polymer particles arc produced. The maximum volume increase due to
swelling and polymerization is about .times.5 or less. The late
Professor John Ugelstad found that the capacity of the seeds to
swell could be increased to a volume increase of .times.125 or even
more if an organic compound with relatively low molecular weight
and low water solubility is diffused into the seeds before the bulk
of the monomer is used to swell the seeds. The effect is based on
entropy and not particularly in the chemical nature of the organic
compound. Conveniently the polymerization initiator may be used for
this purpose. Organic solvents, e.g. acetone or a relatively small
portion of the monomer, may be used to enhance diffusion of the
organic compound into the seeds. This "Ugelstad polymerization
process", which is described for example in EP-B-3905 (Sintef) and
U.S. Pat. No. 4,530,956 (Ugelstad), may be used to produce
monodisperse particles, if necessary carrying out several swelling
and polymerization stages to reach the desired particle size.
[0005] WO 92/16581 (Cornell Research Foundation) also describes the
preparation of monodisperse particles, particularly macroporous
polymer beads. The process described uses a three phase emulsion
containing soluble polymer particles, a monomer phase, and water.
The three phase emulsion also includes an emulsifier and a
suspension stabilizer. The polymer particles undergo swelling
absorbing the monomer which is then polymerized. In this process
the soluble polymer seed particles act as both shape/size
regulators and as a porogen. The initial (i.e. before swelling)
particles have a diameter of from about 0.5 to 10 .mu.m, 2 to 5
.mu.m being most preferred, and are produced by conventional
techniques, such as emulsion or dispersion polymerization.
[0006] In a simplified version of the Ugelstad process the enhanced
capacity for swelling may be achieved simply by the use of
oligomeric seed particles, e.g. where the oligomer weight average
molecular weight corresponds to up to 50 monomer units or up to
5000 Dalton.
[0007] The processes described in EP-B-3905 and U.S. Pat. No.
4,530,956 (the disclosures of which are hereby incorporated by
reference) and the simplified Ugelstad process are relatively
complex and inefficient. The processes described in WO 92/16581 do
not especially improve upon those disclosed in EP-3-3905 and U.S.
Pat. No. 4,530,956. The essence of WO 92/15681 would appear to be
the production of macroporous polymer beads of substantially
uniform size, the macroporosity being achieved through extraction
of the (initially) soluble polymer from the resultant insoluble
expanded beads. It is well known in the art that addition of steric
stabilizers to dispersion polymerizations of polymer seeds can be
useful in controlling size of beads; this feature of WO 92/16581,
therefore, appears to represent nothing more than the arbitrary
introduction of an obvious and well-known advantageous process
feature into the process of the invention.
[0008] There is a need for improvements to all these processes, in
particular improvements which make it easier to produce
monodisperse polymer particles with different chemical or physical
characteristics.
DETAILED DESCRIPTION OF THE INVENTION
[0009] It is important to use a polymeric steric stabilizer in the
aqueous phase in order to avoid agglomeration of desired-sized
particles and formation of undersized particles in the
polymerization stage. Surprisingly it has been found that where the
swelling generates particles below 25 .mu.m in size undersized
particle formation is essentially avoided by the use of
polyvinylpyrrolidone (PVP) as a steric stabilizer whereas where the
swelling generates particles above 5 .mu.m in size cellulose ethers
function effectively as steric stabilizers. While PVP can be used
to stabilize particles above 16 .mu.m it is especially preferred
for use with particles up to 16 .mu.m.
[0010] Thus viewed from one aspect the invention provides a process
for the preparation of monodisperse polymer particles which process
comprises:
[0011] 1) either
[0012] (a) forming an aqueous dispersion comprising (i)
monodisperse swellable seed polymer (or oligomer) particles, (ii)
droplets comprising an organic compound (e.g. a polymerization
initiator) with a molecular weight below 5000 Dalton and a water
solubility at 25.degree. C. of less than 10.sup.-2 g/L, (iii) an
anionic surfactant, and, optionally, (iv) an organic solvent in
which said organic compound is soluble,
[0013] and (b) allowing said organic compound to diffuse into said
seed particles
[0014] or (a) forming an aqueous dispersion comprising monodisperse
swellable seed oligomer particles and preferably an anionic
surfactant;
[0015] 2) contacting the aqueous dispersion of seed particles with
a monomer which, where said organic compound is present, is at
least ten times more water soluble than said organic compound, and
if required a water-soluble steric stabilizer, if required a
porogen, and if required a polymerization initiator, and allowing
said monomer to diffuse into said seed particles to form an aqueous
dispersion of swollen seed particles; and
[0016] 3) initiating polymerization of said monomer in an aqueous
dispersion of swollen seed particles, characterized in that
[0017] where the mode diameter of said swollen particles is greater
than 5 .mu.m then the aqueous phase of said aqueous dispersion of
swollen seed particles during polymerization further contains as a
steric stabilizer a water soluble cellulose ether
[0018] or in that where said mode diameter of said swollen
particles is in the range 1 to 25 .mu.m the aqueous phase of said
aqueous dispersion of swollen seed particles during polymerization
further contains as a steric stabilizer polyvinylpyrrolidone.
[0019] Alternatively, the process feature 2) above may instead
involve contacting the aqueous dispersion of seed particles with a
monomer which, where said organic compound is present, is at least
ten times more water soluble than said organic compound, and
allowing said monomer to diffuse into said seed particles to form
an aqueous dispersion of swollen seed particles, and if required
adding a water-soluble steric stabilizer, if required adding a
porogen, and if required adding a polymerization initiator.
[0020] In the above process, the mode diameter of said swollen
particles is preferably more than 15 .mu.m where the aqueous phase
of said aqueous dispersion of swollen seed particles during
polymerization further contains as a steric stabilizer a water
soluble cellulose ether.
[0021] Where water soluble cellulose ethers are used when forming
the swollen particles, the mode diameter of the swollen particles
will preferably be less than 200 .mu.m.
[0022] The PVP preferably has a weight average molecular weight of
10 to 2000 kD, more preferably 25 to 1500 kD, especially 30 to 1000
kD. Where the swollen particles have sizes at the lower end of the
1 to 25 .mu.m range it is preferred to use lower molecular weight
PVP and where the swollen particles have sizes at the upper end of
that range it is preferred to use higher molecular weight PVP. Thus
for example 20 to 80 kD, e-g. 30 kD PVP is particularly suitable
for swollen particle sizes of up to 8 .mu.m while 900 to 1500 kD
PVP is particularly suitable for swollen particle sizes above 8
.mu.m. Examples of suitable such PVP include PVP K30 and PVP K90
(available for example from International Specialty Products and
from Fluka).
[0023] Examples of suitable cellulose ethers include alkyl
celluloses, preferably C.sub.1-4 alkyl celluloses; and
(hydroxyalkyl)alkylcelluloses, preferably (hydroxy-C.sub.1-4
alkyl)C.sub.1-4-alkyl celluloses, more preferably
(hydroxy-C.sub.1-4-alkylmethyl celluloses. Typically, these
cellulose ethers have weight average molecular weights in the range
10 to 100 kD, especially 15 to 80 kD. Such materials are available
commercially in a range of different degrees of substitution and
molecular weight, e.g. as Benecel MP 333C, Benecel MP 651C,
Culminal MHPC 1500, Culminal MHPC 400, Walocel MK 400 PFV and
Methocel K100. Cellulose ethers which generate a viscosity when in
2% aqueous solution at 21.degree. C. of 50 to 150 mPas are
especially preferred.
[0024] In the present invention, the size increase by volume (i.e.
the ratio of the volume of the swollen particles to the volume of
the seed particles) is between 30 and 1000 times. It is a preferred
embodiment--that the corresponding ratio with regard to the
increase in diameter is not less than 3.5.
[0025] It should be noted that the process steps recited above may
represent the final swelling and polymerization stage or an
intermediate swelling and polymerization stage in an Ugelstad
polymerization process for preparing monodisperse polymer
particles.
[0026] The mixture which comprises the monomer (or mixture of
monomers) is preferably in the form of an aqueous dispersion when
it is contacted with the polymer particles. Where a polymerization
initiator is contacted with the aqueous dispersion of polymer
particles this too is preferably in the form of an aqueous
emulsion, preferably also containing a polymerizable or
non-polymerizable organic solvent, e.g. alcohols (particularly
C.sub.1-4 alkanols), ethers (especially cyclic ethers), ketones
(e.g. acetone), dialkylsulphoxides, dialkylformamides, monomers,
etc. Water miscible solvents, such as acetone, are however
preferred. The droplet size of both such emulsions is preferably
below 5 .mu.m, e.g. 0.1 to 1 .mu.m, particularly 0.3 to 0.6 .mu.m.
This may be produced using an intensive mixer, e.g. a pressure
homogenizer (such as a Gaulin homogenizer) or a rotor stator mixer.
The steric stabilizer, if present, may be added in whole or in
part, together with the monomer, to the aqueous dispersion of seed
particles; if additional steric stabilizer is required this is
preferably added in aqueous solution form. The steric stabilizer
concentration in the polymerization medium is preferably 1 to 40
g/L, especially 4 to 25 g/L, for polyvinylpyrrolidone and 0.1 to 10
g/L, especially 1 to 5 g/L, for cellulose ethers.
[0027] FIG. 1 shows the degree of swelling (by volume) of dispersed
particles produced in Examples 15-17, from water to THF and from
water to butyl acetate.
[0028] In the Ugelstad polymerization process the initial
substantially monodisperse seed polymer particles may conveniently
be produced by emulsion polymerization. We have found that
particularly suitable initial seed particles may be produced by
effecting that emulsion polymerization under substantially
oxygen-free conditions. Thus viewed from a further aspect the
invention provides a process for the preparation of monodisperse
polymer particles which comprises:
[0029] 1) preparing monodisperse swellable seed particles by
emulsion polymerization under substantially oxygen-free
conditions;
[0030] 2) where said seed particles are non-oligomeric (and
optionally where they are oligomeric), (a) contacting said seed
particles with an aqueous dispersion comprising an organic compound
(e-g. a polymerization initiator) with a molecular weight below
5000 Dalton and a water solubility at 25.degree. C. of less than
10.sup.-2 g/L, an anionic surfactant and, optionally an organic
solvent in which said organic compound is soluble, and (b) allowing
said organic compound to diffuse into said seed particles;
[0031] 3) contacting the aqueous dispersion of seed particles with
a monomer which, where said organic compound is used, is at least
ten times more water soluble than said organic compound and
allowing said monomer to diffuse into said seed particles to form
an aqueous dispersion of swollen seed particles, and if required
adding a water-soluble steric stabilizer, if required adding a
porogen, and if required adding a polymerization initiator; and
[0032] 4) initiating polymerization of said monomer in an aqueous
dispersion containing a steric stabilizer in the continuous
phase.
[0033] If desired the resulting particles may be further swollen
and polymerized to obtain larger monodisperse polymer or oligomer
particles. Where any of these stages produces swollen particles
having sizes from 1 to 25 .mu.m polyvinylpyrrolidone is preferably
used as the steric stabilizer and if it produces swollen particles
having sizes above 15 .mu.m a cellulose ether is preferably used as
the steric stabilizer. A cellulose ether may also be used as steric
stabilizer where the mode diameter of said swollen particles is
from 5 to 15 .mu.m. Where the swollen particles have particle sizes
below 5 .mu.m, and especially below 2 .mu.m, and especially where
the organic compound used is a polymerization initiator, it is
convenient to use as the surfactant a C.sub.8-16 alkyl sulphate or
sulphonate, especially a dodecyl sulphate, e-g. sodium dodecyl
sulphate, as this serves as both stabilizer and initiator uptake
promoter. Where the seed particles have mode particle diameters
below 1 .mu.m, the surfactant is especially preferably sodium
dodecyl sulphate.
[0034] Where the monomer is an amino-functionalized monomer (or
where two or more monomers are used and one comonomer is an amino
functionalized monomer), it is preferred to add the initiator after
the seed particles have been swollen and thus to use as the organic
compound (i.e. substance I of EP-3-3905) a non-initiator, e.g. a
material such as dioctyladipate. For such amino monomers, the
initiator is preferably an azo compound, e.g.
2,2'-azobis-(2-methylbutyronitrile) or
azo-bis-dimethylvaleronitrile. For other monomers, especially vinyl
monomers (e.g., styrene) and acrylic monomers, it is preferred to
use a peroxide initiator (e.g. dibenzoyl peroxide, lauroyl
peroxide, t-butyl-peroxybenzoate, t-butyl-peroxypivalate and,
especially, dioctanoyl peroxide) and to use the initiator as the
organic compound which promotes swelling of the seed particles.
[0035] Generally, it is preferred to use polymerization initiators
that are activated by heat. In this way the initiator and monomer
may be brought together within the swollen seed particles at a
temperature below that of which polymerization occurs and the
aqueous dispersion may then be heated to the temperature at which
polymerization is to take place, e.g. 50 to 90.degree. C., more
generally 60 to 85.degree. C. During the polymerization, the
aqueous dispersion goes through a sticky state and the dispersion
should be stirred as gently as possible while still sufficient to
maintain a homogeneous dispersion.
[0036] In the final swelling and polymerization stage, it is
preferred to raise the temperature, e.g. to 70 to 95.degree. C., at
the end of the polymerization stage so as to reduce the quantity of
residual monomer.
[0037] Following preparation of the monodisperse polymer particles
of the desired size (which may require two or more swelling and
polymerization cycles, e.g. up to 10 such cycles), the polymer
particles' surfaces may be derivatized as desired, e.g. by reaction
with bifunctional reagents (e.g. diamines) which react with
functional groups present in monomers used in the final
polymerization stage and serve to introduce the desired functional
groups, e.g. amine, carboxyl, epoxy, hydroxyl, etc. Such functional
groups may likewise be introduced by the use of a functionalized
monomer or comonomer, e.g. glycidyl methacrylate, HEMA, MMA or
aminostyrene. Such groups are advantageous as the resultant
particles are particularly suitable for end uses in applications
such as combinatorial chemistry, peptide synthesis, supported
catalysts and chromatographic separation.
[0038] Depending on their desired end use, the monodisperse polymer
particles may be coated (e.g. with metallic coatings); they may
have materials, e.g. magnetic crystals, specific binding partners
(e.g. antibodies, avidin or streptavidin, etc.), or catalysts bound
to their surface or deposited in pores or on the surface; or they
may be expanded (e.g. using blowing agents).
[0039] The swelling and polymerization stages are performed in
aqueous dispersion in the presence of materials, e.g. surfactants,
stabilizers, organic solvents, etc., which it is desirable to
remove from the particles. Likewise, where the polymerization
produces a cross-linked polymer it may be desirable to remove
linear polymers or oligomers which formed the seed particles, for
example to avoid leakage during use in chromatography. Generally a
water-miscible organic solvent in which the cross-linked polymer is
insoluble, or an aqueous solution of such a solvent, may be used
for this. However it is particularly suitable to use butyl acetate
in this regard in view of its surprising effectiveness in removing
undesired residues from the Ugelstad polymerization process. This
use forms a further aspect of the present invention. Viewed from
this aspect the invention provides a method of cleaning
monodisperse polymer particles, in particular particles produced by
swelling a seed polymer or oligomer particle in aqueous dispersion
and polymerizing a monomer within the swollen seed particles, which
method comprises contacting said monodisperse polymer particles
with butyl acetate, e.g. by washing or rinsing with butyl acetate
or a solution thereof.
[0040] The initial polymer seed (i.e. the particles not produced by
the Ugelstad swelling and polymerization technique) is preferably
prepared by dispersion or emulsion polymerization, in the latter
case especially preferably under substantially oxygen-free
conditions (e.g. under an inert gas atmosphere, for example a noble
gas such as argon, helium, etc.), and with an oxygen content in the
aqueous phase of between 0 and 5 ppm, more especially between 0 and
3 ppm, preferably between 0 and 2 ppm, particularly between 0.01
and 2 ppm. This can be achieved by boiling the water before use or,
more preferably by purging liquid reagents with nitrogen. When
purging liquid reagents with nitrogen, the length of time required
depends upon the volume to be purged. For example, when purging a 2
litre vessel, a purging time of between 1 to 50 minutes is
preferred, especially preferably purging for at least 10
minutes.
[0041] The aqueous phase in the emulsion polymerization contains an
anionic surfactant stabilizer, e.g. an C.sub.8-16 alkyl sulphate
such as a decylsulphate, e.g. sodium decylsulphate. This is
preferably present at a concentration below its critical micelle
concentration.
[0042] The unswollen initial seed preferably has a mode particle
diameter in the range 0.2 to 1 .mu.m, especially 0.3 to 0.7 .mu.m,
more especially 0.4 to 0.6 .mu.m. This can be achieved by mixing
monomer, water and surfactant, heating (e.g. to 80.degree. C.) and
charging with initiator under vigorous stirring. The initial seeds
produced by emulsion polymerization are preferably styrene
polymers. Subsequent seeds may conveniently be polymeric or
oligomcric.
[0043] In the process steps recited above for the processes of the
invention, where the polymerization initiator is used as the
organic compound (i.e. as substance I of the process of EP-B-3905)
it is preferably an organic peroxide, e.g. tert-butyl
peroxyneodecanoate or more especially dioctanoyl peroxide (DOP) and
it is preferably formed into a fine emulsion using water, the
anionic surfactant (preferably sodium dodecyl sulphate or a
sulfonate) and an organic solvent, e.g., acetone. The monomer may
be but preferably is not used as a solvent for the peroxide
initiator; if it is used as a solvent it is preferred that only a
relatively small amount of the monomer be used.
[0044] In general, emulsification is preferably effected using a
high pressure mixer (e.g. a pressure homogenizer), or a rotor
stator mixer, to give a mode droplet diameter in the range 0.05 to
5 .mu.m, more preferably 0.05 to 0.5 .mu.m, especially 0.05 to 0.3
.mu.m. During emulsifications, the surfactant is preferably present
above its critical micelle concentration, e.g. at a concentration
of 3 to 10 g/L, more preferably 4 to 6 g/L (the critical micelle
concentration for sodium dodecyl sulphate is about 2.5 g/L).
However during polymerization stages, the surfactant is preferably
present below its critical micelle concentration, e.g. at less than
1.5 g/L, conveniently 0.1 to 1.0 g/L. This can be achieved either
by dilution, for example, with water after emulsion formation but
before polymerization initiation. Alternatively, the desired
concentration may be achieved by dilution, for example with water
or a solution of a steric stabilizer after emulsion formation but
before polymerization initiation. As a further alternative, the
desired concentration may be realized by adding an appropriately
diluted solution of steric stabilizer prior to emulsion
formation.
[0045] During the uptake of the organic compound by the polymer
seed particles, the temperature of the dispersion is preferably
maintained between 20 and 50.degree. C. as precipitation may occur
at lower temperatures and new particles may form at higher
temperatures. Generally temperatures of 25.degree. C..+-.2.degree.
C. are preferred.
[0046] During this uptake phase the dispersion is preferably
stirred. The time required for uptake is dependant on the seed
diameter, the quantity and nature of the organic compound, the
emulsion droplet size and the quantity and nature of surfactant and
organic solvent. Generally a period of 1 to 5 days, more
particularly 2 to 3 days, will be sufficient. Where the organic
compound is an initiator it is important that uptake be at least
substantially complete so as to avoid out-of-size particles.
[0047] The organic solvent concentration in the dispersion during
organic compound uptake is conveniently 5 to 15% w/w.
[0048] The monomers and comonomers used in the process of the
invention are preferably vinyl monomers (e.g. styrene), acrylic
monomers and methacrylate monomers and monomers copolymerizable
therewith, e-g. styrene, divinylbenzene (DVB), ethyl vinyl benzene,
vinyl pyridine, amino-styrene, methyl-styrene, ethylene
dimethacrylate, (EDMA), hydroxyethylmethacrylate (HEMA), methyl
methacrylate (MMA), glycidyl methacrylate (GMA), vinyl benzyl
chloride (VBC), vinylchloride (VC), dimethyl styrene, ethyl
styrene, ethyl-methyl-styrene, p-chlorostyrene,
2,4-dichlorostyrene, acrylic acid, methyl acrylate, ethyl acrylate,
butylacrylate, methacrylic acid, ethyl methylmethacrylate, maleic
acid, maleic anhydride, dimethyl maleate, diethyl maleate, dibutyl
maleate, fumaric acid, dimethyl fumarate, diethyl fumarate and
acrylonitrile.
[0049] In the process of the invention the initial polymer seed,
e.g. made by emulsion polymerization, is a polymer. Especially
preferably, the initial polymer seed is a styrene homo or
copolymer, e.g. a styrene homopolymer or a styrene-divinyl benzene
copolymer. Most preferably, initial seeds prepared by emulsion
polymerization will be homopolymers, especially polystyrene.
Initial seeds prepared by other techniques, e-g. dispersion
polymerization may be homopolymers or copolymers, and may be
oligomeric or polymeric. Such seeds typically may be 1 to 10 .mu.m
in mode diameter and optionally may contain some cross-linker.
Initial seeds used in this invention which are produced by emulsion
polymerization, on the other hand, are typically of less than or
equal to about 1 .mu.m in diameter.
[0050] Intermediate seeds may be either polymer or oligomer seeds.
Throughout this application, oligomer is intended to refer to
polymers having low weight average molecular weight (for example up
to 5000 Daltons, e.g. 1000 to 4000 D, especially 1500 to 3000 D),
corresponding for example up to 50, more particularly 10 to 25
monomer units. Oligomer seeds have the advantage that their
swelling capacity is generally much greater than that of the longer
chain polymers.
[0051] For intermediate or larger sized seeds, e.g. having a mode
particle diameter of about 1 .mu.m or above before swelling, it may
be desirable to incorporate a chain transfer agent, e.g. a
halogenated alkane as described by Ugelstad in U.S. Pat. No.
4,186,120. This has the advantage of producing a polymer with a
bimodal molecular weight distribution in the polymerization stage.
The lower molecular weight component results in the particles
produced in that polymerization stage having a greater swelling
capacity for subsequent swelling and polymerization stages.
[0052] As an alternative to the use of a chain transfer agent, a
high initiator concentration may be used in oligomer production. In
this regard, the techniques of U.S. Pat. No. 4,530,956 (Ugelstad),
the disclosure of which is incorporated by reference, may be
used.
[0053] It is also preferred to include a water-soluble
polymerization inhibitor (e.g. potassium iodide) in the aqueous
phase to prevent nucleation of particles.
[0054] Where a porous product is desired, then a porogen should be
incorporated in the swollen seed particles, preferably in at least
the final swelling and polymerization stage. As porogens can be
used organic substances which are not polymerized in the
polymerization stage and which can be removed from the particles
after polymerization thereby producing porous particles. Porogens
can also be used as blowing agents -particles impregnated with such
materials, on heating may expand as the porogen vaporizes. Examples
of suitable porogens include organic acids, alcohols, esters,
aromatic solvents, optionally substituted aliphatic hydrocarbons
having up to 12 carbons, e.g. toluene, cyclohexanol, butyl acetate,
propane, pentane, cyclopentane, cyclobutane, heptane, methyl
chloride, ethyl chloride, dichlorodifluoromethane, etc. Toluene and
n-heptane are preferred, especially in a volume ratio of 1:10 to
10:1, more particularly 1:4 to 4:1. The porogen is conveniently
introduced in admixture with the monomer.
[0055] By the use of a combination of porogens, at least one of
which is a solvent for the polymer produced in the polymerization
stage and at least one of which is a not a solvent for that
polymer, it is possible to achieve a desired pore size distribution
in the resulting porous particles. Thus for example for vinyl
polymers (e.g. styrene) toluene can be used as a solvent porogen
and n-heptane as a non-solvent porogen. The use of the term
"solvent" in this specific context is not intended to convey that
the swollen particles are capable of dissolving fully in this
solvent, or that the swollen particles are incapable of dissolving
to any extent whatsoever in the non-solvent porogen. Thus the
combination of the two types of porogen enables the desired pore
size distribution in the resulting porous particles to be achieved.
This use of a porogen combination forms a further aspect of the
invention. Viewed from this aspect the invention provides a process
for the preparation of porous monodisperse polymer particles which
process comprises:
[0056] 1) either
[0057] (a) forming an aqueous dispersion comprising (i)
monodisperse swellable seed polymer (or oligomer) particles, (ii)
droplets comprising an organic compound (e.g. a polymerization
initiator) with a molecular weight below 5000 Dalton and a water
solubility at 25.degree. C. of less than 10.sup.-2 g/L, (iii) an
anionic surfactant, and, optionally, (iv) an organic solvent in
which said organic compound is soluble;
[0058] and (b) allowing said organic compound to diffuse into said
seed particles,
[0059] or
[0060] (a) forming an aqueous dispersion comprising monodisperse
swellable seed oligomer particles and preferably an anionic
surfactant;
[0061] 2) contacting the aqueous dispersion of seed particles with
a monomer which, where said organic compound is present, is at
least ten times more water soluble than said organic compound, and
allowing said monomer to diffuse into said seed particles to form
an aqueous dispersion of swollen seed particles and if required
adding a water-soluble steric stabilizer, if required adding a
porogen, and if required adding a polymerization initiator; and
[0062] 3) initiating polymerization of said monomer in an aqueous
dispersion of swollen seed particles, characterized in that said
swollen seed particles contain at least two porogens, at least one
of which is a solvent for the polymer produced in step (3) and at
least one of which is not a solvent for the polymer produced in
step (3).
[0063] In this aspect, the ratio with regard to increase in
diameter is preferably greater than or equal to 4.5.
[0064] In general, a cross-linking monomer (such as divinylbenzene)
can be used as 0 to 100% w/w of the monomer diffused into the
seeds, for example as at least 30% for the production of porous
particles and up to 0.5% for the production of very highly
swellable particles.
[0065] In the preparation of porous particles and many other
particles, it is necessary to include a crosslinking agent or
alternatively to use as a monomer or comonomer a compound with more
than one polymerization site, e.g. a compound with more than one
polymerizable carbon-carbon double bond, for example a diene such
as divinyl benzene, or compounds such as hexanediol dimethacrylate,
trimethylol propane trimethacrylate and divinyl benzyl ether.
Particularly desirably the monodisperse polymer particles produced
according to the invention are 30 to 100% divinyl benzene, more
especially 60 to 95%, particularly 70 to 90%, more particularly 75
to 82% (where the percentages are by weight of divinylbenzene
monomer residue relative to the total monomer residue).
[0066] It has been found that the Ugelstad processes can be used
particularly effectively to produce functionalized or
functionalizable monodisperse particles where the monomer dispersed
into the seeds in at least one swelling stage, preferably the final
stage, comprises at least two acrylic or methacrylic acid or ester
monomers, more preferably at least one being glycidyl methacrylate.
Viewed from a further aspect therefore the invention provides a
process for the preparation of monodisperse polymer particles which
process comprises:
[0067] 1) either
[0068] (a) forming an aqueous dispersion comprising (i)
monodisperse swellable seed polymer (or oligomer) particles, (ii)
droplets comprising an organic compound (e.g. a polymerization
initiator) with a molecular weight below 5000 Dalton and a water
solubility at 25.degree. C. of less than 10.sup.-2 g/L, (iii)an
anionic surfactant, and, optionally, (iv) an organic solvent in
which said organic compound is soluble;
[0069] and (b) allowing said organic compound to diffuse into said
seed particles;
[0070] or
[0071] (a) forming an aqueous dispersion comprising monodisperse
swellable seed oligomer particles and preferably an anionic
surfactant;
[0072] 2) contacting the aqueous dispersion of seed particles with
a monomer which, where said organic compound is present, is at
least ten times more water soluble than said organic compound, and
allowing said monomer to diffuse into said seed particles to form
an aqueous dispersion of swollen seed particles and if required
adding a water-soluble steric stabilizer, if required adding a
porogen, and if required adding a polymerization initiator; and
[0073] 3) initiating polymerization of said monomer in an aqueous
dispersion of swollen seed particles, characterized in that said
monomer comprises at least two acrylic or methacrylic acid or ester
monomers, more preferably at least one being glycidyl
methacrylate.
[0074] In this aspect, the ratio with regard to increase in
diameter is preferably greater than or equal to 4.5.
[0075] Coefficient of variation (CV) is determined in percentage
as
CV=100.times.standard deviation/mean
[0076] where mean is the mean particle diameter and standard
deviation is the standard deviation in particle size. CV is
preferably calculated on the main mode, i.e. by fitting a monomodal
distribution curve to the detected particle size distribution. Thus
some particles below or above mode size may be discounted in the
calculation which may for example be based on about 90%, more
usually about 99% of total particle number (of detectable particles
that is). Such a determination of CV is performable on a Coulter
Counter Channclizcr 256 particle size analyzer.
[0077] Embodiments of the invention are illustrated further by the
following non-limiting Examples:
EXAMPLES
Example 1
[0078] Porous Crosslinked Polystyrene Particles, 30 .mu.m
[0079] 1400 g of water, 84 g of dioctanoyl peroxide (DOP), 140 g of
acetone and 7 g of sodium dodecyl sulphate (SDS) were homogenized
in a two stage Manton Gaulin homogenizer with 380 kg/cm.sup.2 in
the first stage and 100 kg/cm.sup.2 in the second stage for 8-9
min.
[0080] After homogenization 178.1 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. There were used 21.9 g of
seed suspension containing 19.8 g of water and 2.1 g of oligomeric
particles.
[0081] After stirring for 3 days at 25.degree. C., 180.8 g of the
activated seed particles were charged with an emulsion containing
1683 g of water, 0.6 g of sodium dodecyl sulfate (SDS), 2.6 g of
Methocel K100 (HPMC=Hydroxy Propyl Methyl Cellulose), 117 g of 80%
divinylbenzene (DVB) [i.e. 80% by weight DVB, 20% by weight ethyl
vinyl benzene and other byproducts of DVB production], 223 g of
porogen (to 1 uene:n-heptane in a 1:2 volume ratio). The emulsion
was homogenized at 330 kg/cm.sup.2 in the first stage and 50
kg/cm.sup.2 in the second stage for 6-7 min.
[0082] After swelling for 15 hrs at 25.degree. C., 5.3 g of
Methocel K100 dissolved in 788 g of water were charged to the
reactor. The dispersion was then polymerized for 10 hrs at
70.degree. C. A monodisperse suspension was formed having a
particle diameter of 30 .mu.m.
[0083] The particles were separated from the liquid phase by
flotation and the liquid phase was discharged. The particles were
then cleaned with 2 litres of methanol by stirring for 1 hour
followed by sedimentation. After sedimentation the liquid phase was
discharged, new methanol (2 litres) was charged and the described
procedure was repeated 4 times. The particle suspension was then
sieved through a 100 .mu.m sieving cloth. Then the particle
suspension was diafiltered with 6 litres of butylacetate followed
by 6.7 litres of methanol. Finally the particles were cleaned by
sedimentation and discharging of the liquid phase, with 2 litres of
methanol minimum 3 times.
[0084] The final product was 30 .mu.m polymer particles in a clear
liquid phase without impurities.
Example 2
[0085] Porous Acrylic Particles, 30 .mu.m
[0086] 1400 g of water, 84 g of DOP, 140 g of acetone and 7 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
380 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 8-9 min.
[0087] After homogenization, 88.4 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. There were used 9.6 g of
seed suspension containing 8.75 g of water and 0.85 g of oligomeric
particles.
[0088] After stirring for 3 days at 25.degree. C., 89 g of the
activated seed particles were charged with an emulsion containing
844 g of water, 1.3 g of Methocel K100, 44.9 g of ethylene
dimethylacrylate (EDMA), 11.4 g of hydroxy ethyl methacrylate
(HEMA), 113 g of porogen (cyclohexanol:butylacetate in a 1:1 volume
ratio). The mixture was emulsified with a Ultra Turrax at maximum
speed for 10 min.
[0089] After swelling for 2 hrs at 25.degree. C., 0.4 g of
potassium iodide (KI) dissolved in 395 g of water were charged to
the reactor and the dispersion was then polymerized for 1 hr at
50.degree. C., 3 hrs at 60.degree. C. and 1 hr at 70.degree. C. A
monodisperse suspension was formed having a particle diameter of 30
.mu.m.
Example 3
[0090] Solid Polystyrene Particles, 20 .mu.m
[0091] 1400 g of water, 84 g of DOP, 140 g of acetone and 7 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
380 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 8-9 min.
[0092] After homogenization 159 g of the emulsion were charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. There were used 43.9 g of
seed suspension containing 39.7 g of water and 4.2 g of oligomeric
particles.
[0093] After stirring for 2 days at 25.degree. C., 184.4 g of the
activated seed particles were charged with an emulsion containing
836 g of water, 1.5 g of Methocel K100, 348.8 g styrene. The
emulsion was homogenized at 400 kg/cm.sup.2 in the first stage and
100 kg/cm.sup.2 in the second stage for 4-5 min.
[0094] After swelling for 2 hrs at 25.degree. C., 3 g of Methocel
K100 dissolved in 427 g of water were charged to the reactor and
then the dispersion was polymerized for 1 hr at 60.degree. C. and 9
hrs at 70.degree. C. A monodisperse suspension was formed having a
particle diameter of 20 .mu.m.
Example 4
[0095] Solid Crosslinked Polystyrene Particles, 54 .mu.m
[0096] 1400 g of water, 42 g of DOP, 222 g of acetone and 7 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
400 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 8-9 min.
[0097] After homogenization 159 g of the emulsion were charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 9.5 .mu.m. There were used 17.6 g of
the seed suspension containing 16.6 g of water and 1 g of
oligomeric particles.
[0098] After stirring for 3 days at 25.degree. C., 146.3 g of the
activated seed particles were charged with an emulsion containing
1198 g of water, 2.5 g of Methocel K100, 228 g styrene, 7.3 g 65%
DVB. The emulsion was homogenized at 400 kg/cm.sup.2 in the first
stage and 100 kg/cm.sup.2 in the second stage for 5-6 min.
[0099] After swelling for 1 hour at 25.degree. C., 0.5 g of
Methocel K100 and 0.5 g KI dissolved in 500 g of water were charged
to the reactor and then the dispersion was polymerized for 1 hr at
60.degree. C. and 9 hrs at 70.degree. C. A monodisperse particle
suspension was formed having a particle diameter of 54 .mu.m.
Example 5
[0100] Solid Crosslinked Polystyrene Particles, 15 .mu.m
[0101] 1400 g of water, 84 g of DOP, 140 g of acetone and 7 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
400 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 8-9 min.
[0102] After homogenization 75.8 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 3.2 .mu.m. There were used 22 g of
the seed suspension containing 20 g of water and 2 g of oligomeric
particles.
[0103] After stirring for 1 day at 25.degree. C., 85 g of the
activated seed particles were charged with an emulsion containing
784 g of water, 1.25 g of SDS, 204.3 g styrene, 0.37 g of 80% DVB.
The emulsion was homogenized at 400 kg/cm2 in the first stage and
100 kg/cm2 in the second stage for 4-5 min.
[0104] After swelling for 5 hrs at 25.degree. C., 15 g of PVP K90
(Poly Vinyl Pyrolidonc) and 0.4 g of potassium iodide dissolved in
702 g of water were charged to the reactor and then the dispersion
was polymerized for 1 hr at 60.degree. C. and 9 hrs at 70.degree.
C. A monodisperse suspension was formed having a particle diameter
of 15 .mu.m.
Example 6
[0105] Porous Crosslinked Polystyrene Particles, 4.5 .mu.m
[0106] 4970 g of water, 248.5 g of DOP and 24.85 g of SDS were
homogenized in a two stage Manton Gaulin homogenizer with 400
kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the second
stage for 25 min.
[0107] After homogenization 3947.6 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 1 .mu.m. There were used 1691.2 g of
the seed suspension containing 1555.2 g of water and 136.0 g of
oligomeric particles.
[0108] After stirring for 20 hrs at 25.degree. C., 5126.2 g of the
activated seed particles were charged with an emulsion containing
42576 g of water, 26.47 g of SDS, 536.5 g of PVP K-30, 2989.7 g of
62.5% DVB, 1991.7 g of styrene and 4727.0 g of porogen (toluene).
The emulsion was homogenized at 380 kg/cm.sup.2 in the first stage
and 100 kg/cm.sup.2 in the second stage for 30 min.
[0109] After swelling for 20 hrs at 25.degree. C., 42026.4 g of
water were charged to the reactor and then the dispersion was
polymerized for 1 hr at 60.degree. C., 4 hrs at 70.degree. C. and
2.5 hrs at 80.degree. C. A monodisperse suspension was formed
having a particle diameter of 4.5
Example 7
[0110] Porous Crosslinked Polystyrene Particles, 2.8 .mu.m
[0111] 2630 g of water, 214.4 g of DOP, 291.9 g of acetone and
14.73 g of SDS were homogenized in a two stage Manton Gaulin
homogenizer with 400 kg/cm.sup.2 in the first stage and 100
kg/cm.sup.2 in the second stage for 25 min.
[0112] After homogenization 2994.6 g of the emulsion were charged
with a seed suspension of monodisperse polystyrene particles having
a particle diameter of 0.5 .mu.m. There were used 341.3 g of seed
suspension containing 290.4 g of water and 50.9 g of polymeric
particles.
[0113] After stirring for 20 hrs at 25.degree. C., 3032.6 g of the
activated seed particle suspension were charged with an emulsion
containing 43375.1 g of water, 31.42 g of SDS, 1412.7 g of PVP
K-30, 2989.6 g of 62.9% DVB, 1998.2 g of styrene and 4780.7 g of
porogen (toluene). The emulsion was homogenized at 380 kg/cm.sup.2
in the first stage and 100 kg/cm.sup.2 in the second stage for 60
min.
[0114] After swelling for 20 hrs at 25.degree. C., 42379.7 g of
water were charged to the reactor and then the dispersion was
polymerized for 1 hr at 60.degree. C., 4 hrs at 70.degree. C. and
2.5 hrs at 80.degree. C. A monodisperse suspension was formed
having a particle diameter of 2.8 .mu.m.
Example 8
[0115] Porous Crosslinked Polystyrene Particles, 2.6 .mu.m
[0116] 1548 g of water, 16 g of PVP-K30, 2.4 g SDS, 176.6 g of 63%
DVB, 44 g of styrene, 204.6 g of porogen (toluene) and 5.6 g of
2,2'-azobis(2-methylbutyronitrile) (AMBN) were homogenized in a two
stage Manton Gaulin homogenizer with 400 kg/cm.sup.2 in the first
stage and 100 kg/cm.sup.2 the second stage for 35 min.
[0117] After homogenization 1013.4 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 0.65 .mu.m. There were used 40.4 g of
seed suspension containing 36.8 g of water and 3.58 g of oligomeric
particles.
[0118] After swelling for 20 hrs at 25.degree. C., 8 g PVP K-30,
and 0.8 g of potassium iodide dissolved in 794 g of water were
charged to the reactor and then the dispersion was polymerized for
1 hr at 60.degree. C., 4 hrs at 70.degree. C. and 2.5 hrs at
80.degree. C. A monodisperse suspension was formed having a
particle diameter of 2.6 .mu.m.
Example 9
[0119] Preparation of Initial Seed Particles, 0.5 .mu.m
[0120] 280 g styrene was extracted with 500 ml 10 wt. % sodium
hydroxide and then washed with water to pH7 and then flushed with
argon for 10 min. In a 2 L rector 1400 g of water and 0.53 g of
borax were heated to 80.degree. C., and 100 g water was evaporated
off to remove oxygen. Then 0.56 g sodium decyl sulphate in 50 ml
boiled water was charged and stirred for 10 min, then the washed
and substantially oxygen free styrene was charged and stirred for
15 min. Then 0.84 g potassium peroxodisulphate was charged in 100
ml boiled water. The mixture was kept at 80.degree. C. in an argon
atmosphere for 13 hours. A monodisperse suspension of polymeric
particles was formed having a particle diameter of 0.5 .mu.m.
Example 10
[0121] Solid Methacrylic Particles with Amine Groups, 6 .mu.m
[0122] 900 g of water, 90 g of DOP, 90 g of acetone and 5.4 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
380 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 6-7 min.
[0123] After homogenization 77.0 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 1 .mu.m. There were used 14.5 g of
seed suspension containing 13.2 g of water and 1.3 g of oligomeric
particles.
[0124] After stirring for 1 day at 25.degree. C., 83.3 g of the
activated seed particles were charged with 864.6 g of water, 2.0 g
of SDS, 158.9 g of methyl methacrylate (MMA), 45.4 g glycidyl
methacrylate (GMA) and 22.7 g ethylene glycol-dimethacrylate.
(EDMA).
[0125] After swelling for 15 hrs at 2 S.degree. C., 788 g of water
were charged to the reactor and then the dispersion was polymerized
for 6 hrs at 70.degree. C. Then 38.4 g ethylenediamine were charged
to the reactor and then reaction was allowed to proceed for 18 hrs.
A monodisperse suspension was formed having a particle diameter of
6
Example 11
[0126] Core and Shell Particles, 10 .mu.m
[0127] 1200 g of water, 120 g of DOP, 240 g of acetone and 7.2 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
400 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the
second stage for 7-8 min.
[0128] After homogenization 83 g of the emulsion were charged with
a seed suspension of monodisperse polystyrene particles having a
particle diameter of 2 .mu.m. There were used 7.9 g of the seed
suspension containing 6.5 g of water and 1.4 g of polymeric
particles.
[0129] After stirring for 1 day at 25.degree. C., acetone was
removed by evaporation under vacuum and 71 g of the activated seed
particles were charged with 907 g of water, 2.1 g of SDS, 138.4 g
of methyl styrene, 34.6 g of 55% DVB.
[0130] After swelling for 20 hrs at 25.degree. C., 0.4 g of KI
dissolved in 647 g of water were charged to the reactor and then
polymerized for 5 hrs at 70.degree. C. (core). Then the batch was
cooled down to 25.degree. C.
[0131] Step 2
[0132] 550 g of the suspension of step 1 was taken and the aqueous
was charged with 0.1 g of Methocel J 75MS (Hydroxy Propyl Methyl
Cellulose), 0.05 g of KI and 0.1 g of SDS dissolved in 230 g of
water. To this batch was added a mixture of 15.6 g MMA, 12.5 g of
GMA and 3.1 g of EDMA.
[0133] After stirring for 2 hrs at 25.degree. C., the temperature
was raised to 65.degree. C. for 1 hr and further to 70.degree. C.
for 5 hrs. The final mixture was monodisperse and contained
particles having a diameter of about 10 .mu.m.
Example 12
[0134] Solid Polystyrene Particles with Chlorine Groups, 200
.mu.m
[0135] 1370 g of water, 82 g of DOP, 205 g of acetone and 8.2 g of
SDS were homogenized in a two stage Manton Gaulin homogenizer with
400 kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 the second
stage for 8-9 min.
[0136] After homogenization, 166 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 71 .mu.m. There were used 79 g of the
seed suspension containing 71.2 g of water and 7.8 g of oligomeric
particles.
[0137] After stirring for 2 days at 25.degree. C., 222 g of the
activated seed particles were charged with an emulsion containing
1583 g of water, 8.5 g of Methocel K100, 124.4 g styrene, 3 g of
62.8% DVB, 58.5 g of Vinyl Benzyl Chloride (VBC). The emulsion was
homogenized at 400 kg/cm.sup.2 in the first stage and 100
kg/cm.sup.2 in the second stage for 5-6 min.
[0138] After swelling for 1 hr at 25.degree. C., the temperature
was raised to 60.degree. C. for 1 hr and further to 70.degree. C.
for 10 hrs. A monodisperse suspension was formed having a particle
diameter of 200 .mu.m.
Example 13
[0139] Porous Crosslinked Polystyrene Particles Containing Amine
Functionality, 30 .mu.m
[0140] 1500 g of water, 119 g of bis(2-ethylhexyl) adipate, 152 g
of acetone and 8 g of sodium dodecyl sulphate (SDS)were homogenized
in a two stage Manton Gaulin homogenizer at 400 kg/cm.sup.2 in the
first stage and 100 kg/cm.sup.2 in the second stage for 8-9
min.
[0141] After homogenization, 499 g of the emulsion was charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. 93 g of a seed suspension
containing 8 g of oligomeric particles and 85 g of water was
used.
[0142] After stirring at 45.degree. C. for 1 day, 96.9 g of the
seed suspension containing activated seed particles were charged to
1097.7 g of an emulsion containing 798.3 g of water, 1.2 g of
Methocel K-100, 0.3 g of sodium dodecyl sulphate 34.74 g of 80%
divinylbenzene (DVB) [i.e. 80% by weight DVB, 20% by weight ethyl
vinyl benzene and other byproducts in DVB production], 52.8 g of
styrene, 4.2 g of 2,2'-azobis(2-rnethylbutyronitrile) and 205.7 g
of toluene. The emulsion was homogenized at 400 kg/cm.sup.2 in the
first stage and 100 kg/cm.sup.2 in the second stage for 8-9
min.
[0143] After swelling at 25.degree. C. for 0-5 hours, a mixture of
299.8 g of water, 0.5 g of Methocel K-100, 0.1 g of sodium dodecyl
sulphate and 5.1 g of 4-amino-styrene was charged and the swelling
continued for additional 3 hours. 506.2 g of water and 3.37 g of
Methocel K-100 were then charged to the reactor. The dispersion was
then polymerized for 1 hour at 60.degree. C. and 17 hours at
70.degree. C., yielding a suspension of particles having a diameter
of 30.mu.m.
[0144] The particles were cleaned as described in Example 1.
Example 14
[0145] Porous crosslinked polystyrene particles containing amine
functionality, 30 .mu.m
[0146] 850 g of water, 110.50 g of bis(2-ethylhexyl)adipate, 141.95
g of acetone and 4.25 g of sodium dodecyl sulphate (SDS) were
homogenized in a two stage Manton Gaulin homogenizer at 400
kg/cm.sup.2 in the first stage and 100 kg/cm.sup.2 in the second
stage for 8-9 min.
[0147] After homogenization, 102.68 g of the emulsion was charged
with a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. 27.21 g of seed suspension
containing 1.71 g of oligomeric particles and 26.2 g of water was
used.
[0148] After stirring at 45.degree. C. for 24 hours, 87.06 g of the
seed suspension containing activated seed particles were charged to
1436.08 g of an emulsion containing 1035.84 g of water, 1.58 g of
Methocel K-100, 0.5 g of sodium dodecyl sulphate, 53.41 g of 80%
divinylbenzene (DVB) [i.e. 80% by weight DVB, 20% by weight ethyl
vinyl benzene and other byproducts in DVB production], 56.07 g of
styrene, 6.71 g of 2,2'-azobis(2-methylbutyronitrile), 269.41 g of
toluene and 12.56 g of 4-amino-styrene. The emulsion was
homogenized without addition of 4-amino-styrene at 400 kg/cm.sup.2
in the first stage and 100 kg/cm.sup.2 in the second stage for 8-9
min before the emulsion was mixed with 4-amino-styrene.
[0149] After swelling at 27.degree. C. for 1 hour, a mixture of
473.69 g of water and 3.16 g of Methocel K-100 was then charged to
the reactor. The dispersion was then polymerized for 1 hour at
60.degree. C. and 10 hours at 70.degree. C., yielding a suspension
of particles having a diameter of 30 .mu.m.
[0150] The particles were cleaned as described in Example 1.
Example 15
[0151] Crosslinked Polystyrene Particles Containing Amine
Functionality, 32 .mu.m
[0152] 1380 g of water, 179 g of bis(2-ethylhcxylladipate, 230 g of
acetone and 7 g of sodium dodecyl sulphate (SDS) were homogenized
in a two stage Manton Gaulin homogenizer at 400 kg/cm.sup.3 in the
first stage and 100 kg/cm.sup.3 in the second stage for 10-12
minutes.
[0153] After homogenization 292 g of the emulsion was charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 km. 79 g of seed suspension
containing 7 g of oligomeric particles and 72 g of water was
used.
[0154] After stirring at 45.degree. C. for 1 day, 52.5 g of the
seed suspension containing activated seed particles were charged to
850.5 g of an emulsion containing 0.9 g of Methocel K-100, 0.3 g of
sodium dodecyl sulphate (SDS), 2.1 g of divinylbenzene (DVB) [i.e.
80% by weight DVB, 20% by weight ethyl vinyl benzene and other
byproducts in DVB production], 174.1 g of styrene, 58.7 g of amino
styrene, and 12.9 g of 2,2'-azobis(2-methylbutyro-nitrile). The
mixture was emulsified for 10 minutes by using an Ultra Turrax
mixer.
[0155] After swelling at 27.degree. C. for 1 hour, 281.6 g of water
and 1.9 g of Methocel K-100 were charged to the reactor. The
dispersion was then polymerized for 1 hour at 60.degree. C. and 10
hours at 70.degree. C., yielding a suspension of particles having
diameter of 32 .mu.m.
[0156] The particles were cleaned as described in Example 1.
Diameter was measured on particles dispersed in water, butylacetate
and tetrahydrofuran respectively.
Example 16
[0157] Crosslinked Polystyrene Particles Containing Amine
Functionality, 35 .mu.m
[0158] 1380 g of water, 179 g of bis(2-ethylhexyl)adipate, 230 g of
acetone and 7 g of sodium dodecyl sulphate (SDS)were homogenized in
a two stage Manton Gaulin homogenizer at 400 kg/cm.sup.3 in the
first stage and 100 kg/cm.sup.3 in the second stage for 10-12
minutes.
[0159] After homogenization, 292 g of the emulsion was charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. 79 g of seed suspension
containing 7 g of oligomeric particles and 72 g of water was
used.
[0160] After stirring at 45.degree. C. for 1 day, 52.2 g of the
seed suspension containing activated seed particles were charged to
850.5 g of an emulsion containing 0.9 g of Methocel K-100, 0.3 g of
sodium dodecyl sulphate (SDS), 5.9 g of divinylbenzene (DVB) [i.e.
80% by weight DVB, 20% by weight ethyl vinyl benzene and other
byproducts in DVB production], 166.0 g of styrene, 63.0 g of amino
styrene and 12.9 g of 2,2'-azobis(2-methylbutyro-nitrile). The
mixture was emulsified for 10 minutes by using an Ultra Turrax
mixer.
[0161] After swelling at 27.degree. C. for 1 hour, 281.6 g of water
and 1.9 g of Methocel K-100 were charged to the reactor. The
dispersion was then polymerized for 1 hour at 60.degree. C. and 10
hours at 70.degree. C., yielding a suspension of particles having
diameter of 35 .mu.m.
[0162] The particles were cleaned as described in Example 1.
Diameter was measured on particles dispersed in water, butylacetate
and tetrahydrofuran respectively.
Example 17
[0163] Crosslinked Polystyrene Particles Containing Amine
Functionality, 35 .mu.m
[0164] 1380 g of water, 179 g of bis(2-ethylhexyl)adipate, 230 g of
acetone and 7 g of sodium dodecyl sulphate (SDS) were homogenized
in a two stage Manton Gaulin homogenizer at 400 kg/cm.sup.3 in the
first stage and 100 kg/cm.sup.3 in the second stage for 10-12
minutes.
[0165] After homogenization, 292 g of the emulsion was charged with
a seed suspension of monodisperse oligomeric styrene particles
having a particle diameter of 5 .mu.m. 79 g of seed suspension
containing 7 g of oligomeric particles and 72 g of water was
used.
[0166] After stirring at 45.degree. C. for 1 day, 52.2 g of the
seed suspension containing activated seed particles were charged to
850.5 g of an emulsion containing 0.9 g of Methocel K-100, 0.3 g of
sodium dodecyl sulphate (SDS), 8.8 g of divinylbenzene (DVB) [i.e.
80% by weight DVB, 20% by weight ethyl vinyl benzene and other
byproducts in DVB production], 167.3 g of styrene, 58.75 of amino
styrene, and 12.9 g of 2,2'-azobis(2-methylbutyro-nitrile). The
mixture was emulsified for 10 minutes by using an Ultra Turrax
mixer.
[0167] After swelling at 27.degree. C. for 1 hour, 281.6 g of water
and 1.9 g of Methocel K-100 were charged to the reactor. The
dispersion was then polymerized for 1 hour at 60.degree. C. and 10
hours at 70.degree. C., yielding a suspension of particles having
diameter of 35 .mu.m.
[0168] The particles were cleaned as described in Example 1.
Particle diameter was measured on particles dispersed in water,
butyl acetate and tetrahydrofuran respectively.
[0169] Elemental analysis showed a content of 3.0 wt. % nitrogen
and 0.38 wt. % oxygen.
Example 18
[0170] Further Functionalization of Amine-Functionalized Particles
with Carboxyl and Amide Functionality
[0171] 5 g of the particles produced in Example 17 in methanol were
washed with dioxane (3.times.180 ml). 2.07 g of succinic anhydride
was added to the dioxane suspension (96 g). The mixture was heated
and mechanically stirred at 40.degree. C. for 3 hours. The
particles were washed with dioxanc (2.times.200 ml), methanol (100
ml) and dioxane (200 ml}. IR spectra showed a broad peak at 1750 to
1650 cm.sup.-1 which indicates formation of both amide and
carboxylic acid groups.
[0172] Elemental analysis of dried particles showed a content of
2.5 wt. % nitrogen and 9.3 wt. % oxygen. This indicates an amine
conversion near 100%.
Example 19
[0173] Further Functionalization of Amine-Functionalized Particles
with Amide Functionality
[0174] 5 g of the particles produced in Example 17 in methanol were
washed with dioxane (3.times.180 ml). 4.23 g of bromoacetic acid
bromide and 3.0 g diisopropylethylamine was added to the dioxane
suspension (79 g). The mixture was mechanically stirred at
20.degree. C. for 1 hour. The particles were washed with dioxane
(2.times.150 ml), dioxane with 20% water and 1 g
diisopropylethylamine (150 ml) and dioxane (2.times.150 ml).
[0175] IR spectra showed a peak at 1685 cm.sup.-1 which indicates
formation of amide groups.
[0176] Elemental analysis of dried particles showed a content of
13.2 wt % bromine indicating a conversion of 96%.
Example 20
[0177] Porous Crosslinked Polystyrene Particles, 5.0 .mu.m
[0178] 2020.0 g of water, 202.0 g of DOP, 202.0 g of acetone and
10.10 g of SDS were homogenized in a two stage Manton Gaulin
homogenizer with 400 kg/cm.sup.2 in the first stage and 100
kg/cm.sup.2 in the second stage for 10 minutes.
[0179] After homogenization, 1429.3 g of the emulsion were charged
with a seed suspension of monodisperse oligomeric styrene particles
having particle diameter of 0.9 .mu.m. There were used 372.8 g of
seed suspension containing 341.1 g of water and 31.7 g of
oligomeric particles.
[0180] After stirring for 23 hours at 25.degree. C., 581.3 g of the
activated seed suspension were charged with an emulsion containing
7053.9 g of water, 18.0 g of Methocel K-100, 883.0 g of 80%
divinylbenzene (DVB) [i.e. 80% by weight DVB, 20% by weight ethyl
vinyl benzene and other byproducts in DVB production], 168.1 g of
toluene and 525.6 g of n-heptane. The emulsion was homogenized in a
two stage Manton Gaulin homogenizer with 400 kg/cm.sup.2 in the
first stage and 100 kg/cm.sup.2 in the second stage for 30
minutes.
[0181] After swelling for 20 hrs at 25.degree. C., 3234.2 g of
water and 35.9 g of Methocel K-100 were charged to the reactor and
then the dispersion was polymerized for 1 hour at 60.degree. C. and
10 hours at 70.degree. C. A monodisperse suspension was formed
having a particle diameter of 5 .mu.m.
[0182] The particles were cleaned as described in Example 1.
* * * * *