Field of the invention
The present invention relates to a di-sec-butyl peroxydicarbonate emulsion free
5 of methanol and ethanol, to a process for preparing same and to the use thereof for the
polymerization or copolymerization of one or more ethylenically unsaturated
monomers. The invention also relates to a halogenated vinyl polymer prepared in the
presence of such an emulsion.
10 Technical background
Organic peroxides, in liquid or solid form, are commonly used as
polymerization initiators for ethylenically unsaturated monomers for the synthesis of
various types of polymers.
However, their use frequently presents a certain number of problems.
15 Specifically, organic peroxides usually constitute highly unstable species since they
decompose relatively easily under the action of a slight input of heat, of mechanical
energy (friction or impact) or of incompatible contaminants. Thus, in the event of an
uncontrolled elevation of their storage temperature, certain organic peroxides can
undergo an autoaccelerated exothermic decomposition which can result in fires and/or
20 violent explosions. In addition, under these conditions, some of these organic
peroxides can release combustible vapors that are capable of reacting with any source
of ignition which can drastically increase, or even accelerate, the risks of violent
explosion. As a result, it is important to take appropriate precautionary measures in
terms of safety during the storage and transportation of organic peroxides.
25 In order to overcome these drawbacks, organic peroxides are notably packaged
in the form of aqueous emulsions comprising antifreezes. Thus, the presence of water
makes it possible both to absorb and to dissipate the energy generated in the event of
exothermic decompositions of organic peroxides, while the role of the antifreeze is to
keep the emulsion in liquid form, at temperatures of less than -10°C, generally of less
30 than -15°C, which makes it possible to limit the risks of an involuntary exothermic
decomposition of organic peroxides.
The aqueous emulsions generally also contain an emulsifier having the
advantage of lowering the interfacial tension between the aqueous phase and the
organic peroxide for the purpose of facilitating the dispersion of the peroxide in the
35 form of droplets and of maintaining the size of said droplets over time. Specifically,
over time, the peroxide droplets may sediment, form a cream, or undergo Ostwald
ripening, or may agglomerate together, bringing about an increase in their mean size
and in their maximum size which can result, in certain cases, in total or partial phase
separation and consequently in an overall destabilization of the emulsion.
3
In view of the above, aqueous organic peroxide emulsions must therefore be
stable for safety reasons not only during their production but also for a relatively long
period of time during their transportation and storage before being used as
polymerization initiators. For this purpose, as mentioned above, the organic peroxide
5 droplets must be mainly have small average and maximum sizes.
Thus, the peroxide droplets of an organic peroxide emulsion should have a low
average size and preferably a homogeneous size distribution, and should be stable over
time, preferably over a period of at least three months. In particular, the maximum
diameter of these droplets should very preferably not exceed 20 µm.
10 Moreover, in addition to the safety considerations due to the destabilization
phenomenon described above, it is essential to obtain homogeneous emulsions with a
small droplet size also for considerations of quality and efficiency of the
polymerization process. The reason for this is that the use of a non-homogeneous
organic peroxide emulsion or an emulsion with an excessively large droplet size as
15 polymerization initiator in an emulsion or suspension of vinyl monomer may produce
inhomogeneity in the final product. This inhomogeneity is generally characterized by
polymer particles that are poorly gelled during implementation in molten form (“fish
eyes”, hard grains). Now, the presence of hard grains opacifies the polymer material.
These stability considerations are thus very important for applications in which the
20 transparency of the final product is imperative, notably for medical applications.
Furthermore, the use of non-homogeneous organic peroxide emulsions, i.e.
emulsions having a significant difference in organic peroxide concentration distributed
between the upper and lower part of the aqueous phase, can also give rise to
unpredictable differences in initiator concentration in the polymerization reactor. A
25 difference in initiator concentration in the polymerization reactor can cause a problem
regarding the polymerization time. A concentration that is too low reduces the
productivity of the reactor since the polymerization time is extended, and can have an
impact on the quality of the polymer. A concentration that is too high causes a very
substantial release of energy by the polymerization and thus poses the problem of
30 evacuating this energy. The temperature of the polymerization reactor must then be
controlled by the various cooling means, such as the jacket, refrigerated counter-blades
or a condenser, or else, if the temperature is not well controlled, the polymerization
operation must be stopped.
In addition, the steps of discharging the emulsion in intermediate storage silos,
35 of pumping and of introduction of an organic peroxide emulsion into a polymerization
reactor are steps that are important for the quality of the polymer obtained, the
reliability of the polymerization process and the productivity. These handling steps
must be performed in a short time. To do this, it is important for the peroxide emulsion
to have a low viscosity so that the flow of the emulsion is facilitated.
4
Thus, an organic peroxide emulsion should advantageously have a flowability
measured by a consistometric cup technique of less than or equal to 200 seconds
(measured, for example, according to the standard DIN 53211, with a viscosity cup
diameter of 4 mm and a temperature of 5°C).
5 Various organic peroxide emulsions have been developed.
For example, WO 99/31194 describes organic peroxide emulsions comprising
an antifreeze and a chlorinated paraffin and optionally nonionic surfactants and
protective colloidal agents.
WO 00/42078 relates to peroxide emulsions comprising a copolymer of an α,β10 unsaturated dicarboxylic acid and a C8-C24 α-olefin whose acid groups are esterified
with an ethoxylated alcohol and also an ethoxylated fatty alcohol with an HLB of
greater than 16.
US 5 369 197 describes organic peroxide emulsions comprising a protective
colloidal agent, such as a polyvinyl alcohol or xanthan gum and an alcohol, in
15 particular methanol, ethanol or ethylene glycol.
JP H0676445 relates to peroxide emulsions comprising an antifreeze, a
nonionic surfactant and/or a protective colloidal agent and alkali metal ions, alkalineearth metal ions and hydrogen ions.
GB 2083374 relates to aqueous emulsions comprising an organic peroxide, an
20 alcohol with a molecular mass of less than 100 and an emulsifier comprising a
polyvinyl alcohol.
FR 2995905 relates to aqueous organic peroxide emulsions not containing a
protective colloidal agent, comprising as emulsifier a nonionic surfactant, and also an
antifreeze, preferably a mixture of methanol and propane-1,2-diol.
25 FR 2995906 describes an aqueous organic peroxide emulsion in which the
emulsifying agent is a colloidal agent consisting of a polyvinyl acetate having a degree
of hydrolysis of greater than 80%.
In the particular case of di-sec-butyl peroxydicarbonate, an additional problem
must be taken into account, that of the compatibility of the organic peroxide with the
30 antifreeze.
Indeed, at the present time, the alcohols most commonly used as antifreezes in
organic peroxide emulsions are methanol and ethanol. However, it has been found that
these alcohols induce phase separation of the emulsion and decomposition of the disec-butyl peroxydicarbonate, when they are placed in contact therewith, leading to a
35 deterioration of the emulsion. This incompatibility between di-sec-butyl
peroxydicarbonate and methanol and ethanol is specific to this peroxide and is not
observed with other peroxides, including other peroxydicarbonates.
In addition, di-sec-butyl peroxydicarbonate has the specificity, relative to other
commonly used organic peroxides, of having a density of greater than 1 g/cm3
(at
40 15°C). In emulsion, it therefore tends to sediment, unlike other commonly used organic
5
peroxides, which tend to float. Di-sec-butyl peroxydicarbonate thus has a specific
behavior in emulsion that is very different from that of other commonly used organic
peroxides.
There is thus a real need to provide a di-sec-butyl peroxydicarbonate emulsion
5 which can maintain a low maximum and average droplet size, and which remains
stable and homogeneous over a long period of time.
Summary of the invention
The invention relates firstly to an organic peroxide emulsion comprising:
10 - at least one organic peroxide comprising di-sec-butyl peroxydicarbonate;
- at least one emulsifier;
- at least one antifreeze; and
- water;
said emulsion being free of methanol and ethanol.
15 In certain embodiments, the at least one antifreeze is an alcohol, preferably
chosen from the group consisting of monoalcohols, diols, triols and mixtures thereof.
In certain embodiments, the at least one antifreeze is chosen from the group
consisting of ethylene glycol, 2-propanol, 1-propanol, propane-1,2-diol, propane-1,3-
diol, glycerol, butan-1-ol, butan-2-ol, butan-1,3-diol, butan-1,4-diol, diethylene
20 glycol, triethylene glycol and mixtures thereof.
In certain embodiments, the at least one antifreeze comprises, preferably
consists of, propane-1,2-diol.
In certain embodiments, the at least one antifreeze is present in an amount of
from 10% to 40% by weight, preferably from 15% to 25% by weight, relative to the
25 total weight of the emulsion.
In certain embodiments, the at least one organic peroxide consists of di-secbutyl peroxydicarbonate.
In certain embodiments, the di-sec-butyl peroxydicarbonate is present in an
amount of from 30% to 80% by weight, preferably from 40% to 60% by weight, more
30 preferentially from 45% to 60% by weight, relative to the total weight of the emulsion.
In certain embodiments, the at least one emulsifier comprises a nonionic
surfactant, preferably chosen from the group consisting of oxyalkylenated fatty
alcohols, oxyalkylenated fatty acids, oxyalkylenated plant or animal oils, polysorbates,
sorbitan esters, non-oxyalkylenated alkyl glucosides, oxyalkylenated alkyl glucosides
35 and mixtures thereof.
In certain embodiments, the at least one emulsifier comprises at least one
protective colloidal agent, preferably at least one polyvinyl alcohol and/or hydrolyzed
polyvinyl acetate.
6
In certain embodiments, the at least one emulsifier consists of at least one
protective colloidal agent, preferably at least one polyvinyl alcohol and/or hydrolyzed
polyvinyl acetate.
In certain embodiments, the emulsion is free of polyvinyl alcohol and of
5 hydrolyzed polyvinyl acetate.
The invention also relates to a process for preparing an emulsion as described
above, comprising the following steps:
- mixing the at least one organic peroxide, the at least one emulsifier, the at
least one antifreeze and water; and
10 - emulsifying the mixture.
The invention also relates to the use of an emulsion as described above for the
polymerization or copolymerization of one or more ethylenically unsaturated
monomers, in particular vinyl monomers, preferably halogenated vinyl monomers, and
more preferentially vinyl chloride.
15 The invention also relates to a halogenated vinyl polymer obtained by
polymerization of at least one ethylenically unsaturated monomer in the presence of
an emulsion as described above.
The present invention meets the need expressed above. More particularly, it
provides an emulsion comprising di-sec-butyl peroxydicarbonate which is stable and
20 homogeneous over a long period of time and which retains a small average droplet size
and a small maximum droplet size. The emulsion according to the invention can thus
be transported and stored over long periods in total safety. In addition, the emulsion
according to the invention meets the required conditions in terms of viscosity and flow
time. Furthermore, the emulsion according to the invention allows the production of a
25 polymer, when it used for the polymerization of ethylenically unsaturated monomers,
having a low content of hard grains.
This is achieved by virtue of the presence, in the emulsion, of an antifreeze
combined with the absence of both ethanol and methanol. Indeed, as indicated above,
it was found that the presence of methanol or ethanol in a di-sec-butyl
30 peroxydicarbonate emulsion resulted in decomposition of this peroxide and an
unstable emulsion. Surprisingly, it was found that emulsions comprising an antifreeze
but free of ethanol and methanol remained stable and homogeneous over a long period
of time, had a suitable viscosity, and had droplets that remained of small size.
35 Detailed description
The invention is now described in greater detail and in a nonlimiting manner
in the description that follows.
In the present text, unless expressly indicated otherwise, all the percentages
(%) shown are percentages by weight.
7
In the present text, the amounts indicated for a given species may apply to that
species according to all its definitions (as mentioned in the present text), including the
more restricted definitions.
5 Emulsion
The invention relates firstly to an organic peroxide emulsion. The emulsion
according to the invention is an aqueous emulsion, i.e. it comprises water. Preferably,
the water is demineralized or deionized water.
Particularly preferably, the emulsion is an oil-in-water type emulsion.
10 The emulsion according to the invention comprises at least one organic
peroxide. The at least one organic peroxide comprises di-sec-butyl peroxydicarbonate.
This peroxide is sold, for example, under the trade name Luperox® 225 by Arkema.
Advantageously, the at least one organic peroxide may consist of di-sec-butyl
peroxydicarbonate. Di-sec-butyl peroxydicarbonate is then the only peroxide in the
15 emulsion.
Alternatively, the at least one peroxide may comprise di-sec-butyl
peroxydicarbonate as a mixture with at least a second organic peroxide. The emulsion
according to the invention may comprise a mixture of two organic peroxides, or more
than two organic peroxides, provided that one of the organic peroxides is di-sec-butyl
20 peroxydicarbonate.
The at least one second peroxide is preferably chosen from peroxydicarbonates,
peroxyesters, and/or diacyl peroxides.
Among the peroxydicarbonates, the preferred peroxides are diethyl
peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di25 n-butyl peroxydicarbonate, diisobutyl peroxydicarbonate, di-tert-butyl
peroxydicarbonate, bis(3-methoxybutyl) peroxydicarbonate, dineopentyl
peroxydicarbonate, bis[2-(2-methoxyethoxy)ethyl] peroxydicarbonate, bis(3-
methoxy-3-methylbutyl) peroxydicarbonate, bis(2-ethoxyethyl) peroxydicarbonate,
bis(2-ethylhexyl) peroxydicarbonate, and mixtures thereof.
30 Among the peroxyesters, the preferred peroxides are tert-amyl peroxypivalate,
tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-amyl
peroxyneodecanoate, tert-butyl peroxyisobutyrate, cumyl peroxyneodecanoate, cumyl
peroxyneoheptanoate, 2,4,4-trimethylpentyl peroxyneodecanoate, tert-butyl peroxy-nheptanoate, cumyl peroxy-n-heptanoate, tert-amyl peroxy-n-heptanoate, tert-butyl
35 peroxyneoheptanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-
ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, hydroxyperoxy
esters and mixtures thereof.
As hydroxyperoxyesters that may be used in the emulsion according to the
invention, mention may be made of 4-hydroxy-2-methylpentyl peroxyneodecanoate,
40 4-hydroxy-2-methylpentyl peroxy-(2-ethylhexanoate), 4-hydroxy-2-methylpentyl
8
peroxy-2-phenylbutyrate, 4-hydroxy-2-methylpentyl peroxy-2-phenoxypropionate, 4-
hydroxy-2-methylpentyl peroxy-(2-butyloctanoate), 4-hydroxy-2-methylpentyl
peroxyneotridecanoate, 4-hydroxy-2-methylhexyl peroxyneodecanoate, 5-hydroxy1,3,3-trimethylcyclohexyl peroxyneodecanoate, 4-hydroxy-2,6-dimethyl-2,6-
5 bis(neohexanoylperoxy)heptane, 4-hydroxy-2,6-dimethyl-2,6-
bis(neodecanoylperoxy)heptane, 3-hydroxy-1,1-dimethylbutyl peroxy-2-
ethylhexanoate, 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate and mixtures
thereof.
Among the diacyl peroxides, the preferred peroxides are chosen from the group
10 consisting of diisobutyryl peroxide, diheptanoyl peroxide, bis(2-ethylbutanoyl)
peroxide, bis(3,5,5-trimethylhexanoyl) peroxide, bis(2-ethylhexanoyl) peroxide, and
also asymmetric peroxides such as isobutyroyl octanoyl peroxide, isobutyroyl
decanoyl peroxide, isobutyroyl lauroyl peroxide, 2-ethylbutanoyl decanoyl peroxide,
2-ethylhexanoyl lauroyl peroxide, and mixtures thereof.
15 More preferentially, the second organic peroxide is chosen from the group
consisting of tert-butyl peroxyneodecanoate, for example sold under the name
Luperox® 10 by Arkema, 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate, for
example sold under the trade name Luperox® 610 by Arkema, cumyl
peroxyneodecanoate, for example sold under the name Luperox® 188 by Arkema,
20 bis(2-ethylhexyl) peroxydicarbonate, for example sold under the trade name
Luperox® 223 by Arkema, tert-amyl peroxyneodecanoate, for example sold under the
name Luperox® 546 by Arkema, tert-butyl peroxypivalate, for example sold under the
name Luperox® 11 by Arkema, tert-amyl peroxypivalate, for example sold under the
name Luperox® 554 by Arkema, bis(3,5,5-trimethylhexanoyl) peroxide, for example
25 sold under the name Luperox® 219 by Arkema, and mixtures thereof.
When the emulsion comprises more than two peroxides, each of the peroxides
other than di-sec-butyl peroxydicarbonate may be as described above.
The second organic peroxide(s) according to the invention advantageously
have a one-hour half-life temperature, measured in trichloroethylene, of less than or
30 equal to 90°C, preferably less than 80°C.
Furthermore, the second organic peroxide(s) in the emulsion according to the
invention advantageously have a storage temperature below 0°C.
The second organic peroxide(s) are advantageously liquid at the storage
temperature, preferably at a storage temperature below 0°C, measured at atmospheric
35 pressure.
Preferably, the emulsion according to the invention comprises the at least one
organic peroxide in an amount of from 30% to 80% by weight, preferably from 40%
to 60% by weight, more preferentially from 45% to 60% by weight, relative to the total
weight of the emulsion. In particular the amount of peroxide, relative to the total
40 weight of the emulsion, may be from 30% to 35% by weight, or from 35% to 40% by
9
weight, or from 40% to 45%, or from 45% to 50%, or from 50% to 55%, or from 55%
to 60%, or from 60% to 65%, or from 65% to 70%, or from 70% to 75%, or from 75%
to 80% by weight.
Advantageously, di-sec-butyl peroxydicarbonate is present in the emulsion in
5 an amount of from 30% to 80% by weight, preferably from 40% to 60% by weight,
more preferentially from 45% to 60% by weight, relative to the total weight of the
emulsion. Notably, the amount of di-sec-butyl peroxydicarbonate in the emulsion may
be from 30% to 35% by weight, or from 35% to 40% by weight, or from 40% to 45%,
or from 45% to 50%, or from 50% to 55%, or from 55% to 60%, or from 60% to 65%,
10 or from 65% to 70%, or from 70% to 75%, or from 75% to 80%, by weight, relative
to the total weight of the emulsion.
The emulsion according to the invention comprises at least one antifreeze. The
antifreeze prevents the formation of gels when the emulsion is transported and/or
stored cold, i.e. conventionally in an environment with temperatures below 0°C.
15 The antifreeze is preferably an alcohol. Thus, the antifreeze may be any alcohol
that is water-soluble at the storage temperature, for example at a temperature of 0°C.
The term “water-soluble alcohol” means a solubility of more than 1% in water at 0°C.
The amount of antifreeze in water can be measured by gas chromatography.
More particularly, the antifreeze may advantageously be a monoalcohol, a diol
20 and/or a triol.
Preferably, the antifreeze is chosen from the group consisting of ethylene
glycol, 2-propanol, 1-propanol, propane-1,2-diol, propane-1,3-diol, glycerol, butan-1-
ol, butan-2-ol, butan-1,3-diol, butan-1,4-diol, diethylene glycol, triethylene glycol, and
mixtures thereof, these mixtures comprising at least two of the antifreezes listed
25 previously. The mixtures of antifreezes may comprise two or more antifreezes as
mentioned above, preferably two.
Particularly advantageously, the antifreeze is propane-1,2-diol, optionally as a
mixture with one, or more, antifreezes, preferably as mentioned above. More
advantageously, the antifreeze consists of propane-1,2-diol.
30 The emulsion according to the invention is free of ethanol and free of methanol.
The antifreeze is preferably present in the emulsion according to the invention
in a content of less than or equal to 40% by weight (relative to the total weight of the
emulsion), preferably less than or equal to 25% by weight, more preferably less than
or equal to 22% by weight, relative to the total weight of the emulsion. Such antifreeze
35 contents allow the aqueous phase to remain in liquid form down to temperatures of
less than or equal to -20°C, preferably down to temperatures of less than or equal to -
25°C.
More particularly, the antifreeze may be present in the emulsion in an amount
of from 10% to 40% by weight, preferably from 15% to 25% by weight, relative to the
40 total weight of the emulsion. In certain embodiments, the emulsion comprises from
10
10% to 15% by weight, or from 15% to 20% by weight, or from 20% to 25% by weight,
or from 25% to 30% by weight, or from 30% to 35% by weight, or from 35% to 40%
by weight, of antifreeze, relative to the total weight of the emulsion.
The emulsion according to the invention comprises at least one emulsifier.
5 Preferably, the emulsifier according to the invention is readily biodegradable.
The qualification of the biodegradability of the emulsifier may be determined by the
OECD 301 method and more particularly by the OECD 301 B method by release of
carbon dioxide.
Preferably, the emulsifier comprises, or is (i.e. consists of), a nonionic
10 surfactant. Thus, the emulsion according to the invention may comprise at least one
nonionic surfactant.
Even more preferably, the emulsifier comprises, or is, an oxyalkylenated or
non-oxyalkylenated nonionic surfactant chosen from the group consisting of fatty
alcohols, fatty acids, sorbitan esters, plant or animal oils (hydrogenated or non15 hydrogenated), alkyl glucosides and mixtures thereof. The nonionic surfactant
mixtures used in the invention may be mixtures of oxyalkylenated nonionic surfactants
only, or mixtures of non-oxyalkylenated nonionic surfactants only, or mixtures of
oxyalkylenated nonionic surfactants and non-oxyalkylenated nonionic surfactants.
In certain embodiments, the nonionic surfactant may comprise, or be, one or
20 more poly(ethylene oxide) block copolymers and poly(propylene oxide) block
copolymers, optionally in combination with one or more other nonionic surfactants,
for example as described in the present text.
Advantageously, the emulsifier comprises, or is, a nonionic surfactant chosen
from the group consisting of oxyalkylenated fatty alcohols, oxyalkylenated fatty acids,
25 polysorbates, sorbitan esters, oxyalkylenated plant or animal oils, non-oxyalkylenated
alkyl glucosides, oxyalkylenated alkyl glucosides, and mixtures thereof.
The oxyalkylene units are more particularly oxyethylene units (i.e. ethylene
oxide groups), oxypropylene units (i.e. propylene oxide groups), or a combination of
oxyethylene units and oxypropylene units; preferably, the oxyalkylene units are
30 oxyethylene units or a combination of oxyethylene units and oxypropylene units.
Thus, the nonionic surfactant is preferably chosen from the group consisting of
fatty alcohols containing oxyethylene units and optionally oxypropylene units, fatty
acids containing oxyethylene units and optionally oxypropylene units, polysorbates,
sorbitan esters, plant or animal oils, which are optionally hydrogenated, containing
35 oxyethylene units and optionally oxypropylene units, alkyl glucosides containing
oxyethylene units and optionally oxypropylene units, and mixtures thereof.
The oxyethylene units (i.e. ethylene oxide groups) and oxypropylene units (i.e.
propylene oxide groups) may be randomly distributed or in block form.
11
The number of moles of ethylene oxide and/or propylene oxide preferably
ranges from 1 to 250, more preferentially from 2 to 100, even more preferentially from
2 to 50 and more particularly from 2 to 20.
Preferably, the number of moles of ethylene oxide in the emulsifier ranges from
5 2 to 20.
For the purposes of the present invention, the term “fatty alcohol” means an
alcohol containing at least 6, preferably at least 8, carbon atoms, more preferably a C8-
C40 alcohol, preferentially a C8-C20 alcohol.
Among the fatty alcohols that may be used in the invention, mention may
10 notably be made of 2-octyldodecanol, decanol, lauryl alcohol, oleocetyl alcohol,
isodecanol, capryl alcohol, oxoisotridecanol, cetostearyl alcohol, eleostearyl alcohol,
caprylyl alcohol, myristyl alcohol, hexadecyl or palmityl alcohol, stearyl alcohol,
eicosanyl or arachidyl alcohol, behenyl alcohol, oleyl alcohol, eicosenyl or gadoleyl
alcohol, docosenyl alcohol, ricinoleyl alcohol, linoleyl alcohol, linolenyl alcohol or
15 mixtures thereof.
Preferably, the nonionic surfactant is chosen from the group consisting of
oxyalkylenated fatty alcohols and is preferably chosen from octyldodecanol, decanol,
lauryl alcohol, oleocetyl alcohol, isodecanol, capryl alcohol, oxoisotridecanol,
cetostearyl alcohol, eleostearyl alcohol, caprylyl alcohol, myristyl alcohol, hexadecyl
20 or palmityl alcohol, stearyl alcohol, eicosanyl or arachidyl alcohol, behenyl alcohol,
oleyl alcohol, eicosenyl or gadoleyl alcohol, docosenyl alcohol, ricinoleyl alcohol,
linoleyl alcohol or linolenyl alcohol, which are oxyalkylenated, preferably
oxyethylenated and/or oxypropylenated, and more preferentially oxyethylenated and
optionally oxypropylenated.
25 The fatty alcohols that are more preferred in the context of the invention are
oleocetyl alcohol, hexadecyl or palmityl alcohol, stearyl alcohol, oleyl alcohol, linoleyl
alcohol or mixtures thereof, and even more preferred are the oxyalkylenated,
preferably oxyethylenated and/or oxypropylenated, and more preferably
oxyethylenated and optionally oxypropylenated versions thereof.
30 More preferably, the nonionic surfactant is an oxyalkylenated fatty alcohol
chosen from the group consisting of oxyethylenated linoleyl alcohol, oxyethylenated
oleocetyl alcohol, oxyethylenated hexadecyl or palmityl alcohol, oxyethylenated
stearyl alcohol, oxyethylenated oleyl alcohol, and mixtures thereof.
The abovementioned fatty alcohols may optionally be oxypropylenated to a
35 minor extent.
Preferably, the oxyalkylenated plant/animal oils (hydrogenated or nonhydrogenated) are in particular derivatives of ethoxylated mono-, di- and triglycerides
and comprise a complex mixture of ethoxylated glycerol optionally linked to one or
more fatty acid chains (which are themselves ethoxylated or not), fatty acids
40 ethoxylated on the acid function and/or on the hydroxyl function borne the fatty acid
12
chain, and also variable proportions of fatty acids, glycerol and fatty acid mono-, dior triglycerides.
For the purposes of the present invention, the term “fatty acid” means an acid
or a mixture of acids comprising at least 6 carbon atoms, preferably from 6 to 40 carbon
5 atoms, more preferentially from 8 to 20 carbon atoms.
The oxyalkylenated plant/animal oils (hydrogenated or non-hydrogenated) that
may be used in the invention are preferably chosen from the group consisting of
optionally hydrogenated, oxyethylenated (or ethoxylated) plant oils.
The optionally hydrogenated, oxyethylenated plant oils are preferably chosen
10 from the group consisting of ethoxylated castor oil and ethoxylated hydrogenated
castor oil comprising from 5 to 40 mol of ethylene oxide per mole of ricinoleic acid.
Mention may also be made of ethoxylated oils derived from coconut kernel oil, palm
oil, palm kernel oil, olive oil, groundnut oil, rapeseed oil, soybean oil, sunflower oil,
walnut oil, hazelnut oil, coconut oil, poppy oil, safflower oil, linseed oil, perilla oil,
15 oitica oil, and/or Chinese wood oil.
As plant/animal oils that may be used according to the invention as emulsifiers,
mention may also be made of ethoxylated fats based on tallow oil, crude or refined tall
oil, whale oil, herring oil and/or sardine oil. All these ethoxylated glyceride derivatives
are characterized in that they include mixtures of ethoxylated mono-, di- or
20 triglycerides and also corresponding ethoxylated derivatives of fatty acids and of
glycerol. These fatty acids are notably saturated or unsaturated fatty acids derived from
caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic
acid, arachic acid, behenic acid, myristoleic acid, palmitoleic acid, oleic acid,
ricinoleic acid, erucic acid, linoleic acid, linolenic acid, eleostearic acid, licanic acid,
25 gadoleic acid, and/or erneic acid. Some unsaturated fatty acids may or may not be
hydrogenated as in the case of ethoxylated castor oil in which the ricinoleic group may
or may not have been partially or fully hydrogenated.
In certain embodiments, the emulsifier according to the invention may
comprise, or be, one or more fatty acids, which are preferably oxyalkylenated, more
30 preferably oxyethylenated and optionally oxypropylenated, these fatty acids being
selectable from those listed above.
Advantageously, the emulsifier may comprise, or be, a nonionic surfactant
chosen from the group consisting of oxyalkylenated plant or animal oils (hydrogenated
or non-hydrogenated).
35 More preferentially, the emulsifier may comprise, or be, a nonionic surfactant
chosen from the group consisting of plant oils, which are optionally hydrogenated,
oxyethylenated and optionally oxypropylenated.
More preferentially, the emulsifier may comprise, or be, a nonionic surfactant
chosen from the group consisting of ethoxylated, optionally hydrogenated plant oils
13
including from 5 to 40 mol of ethylene oxide, in particular ethoxylated castor oil and
ethoxylated hydrogenated castor oil including from 20 to 40 mol of ethylene oxide.
Even more preferentially, the emulsifier may comprise, or be, ethoxylated
castor oil including from 20 to 40 mol of ethylene oxide.
5 Advantageously, the emulsifier may comprise, or be, one or more nonethoxylated sorbitan esters and/or one or more ethoxylated sorbitan esters. In the
present text, ethoxylated sorbitan esters are also referred to as “polysorbates”, the term
“sorbitan ester” denoting in the present text non-ethoxylated sorbitan esters, unless
expressly indicated otherwise.
10 Preferably, the non-ethoxylated sorbitan ester is chosen from the group
consisting of sorbitan monostearate, sorbitan tristearate, sorbitan monolaurate,
sorbitan trilaurate, sorbitan monooleate, sorbitan trioleate, sorbitan monopalmitate and
sorbitan tripalmitate and combinations thereof.
Sorbitan monooleate is available under the brand name Span 80® (from
15 Croda).
Preferably, the ethoxylated sorbitan ester (or polysorbate) comprises between
3 and 40 ethylene oxide groups, preferably between 5 and 20 ethylene oxide groups.
Preferably, the ethoxylated sorbitan ester is chosen from the group consisting
of ethoxylated sorbitan monostearate, ethoxylated sorbitan tristearate, ethoxylated
20 sorbitan monolaurate, ethoxylated sorbitan trilaurate, ethoxylated sorbitan
monooleate, ethoxylated sorbitan trioleate, ethoxylated sorbitan monopalmitate,
ethoxylated sorbitan tripalmitate and combinations thereof.
Sorbitan monooleate 20 OE (i.e. containing 20 ethylene oxide groups) is
available under the brand name Surfaline SE80® (from Arkema) or Tween 80® (from
25 Croda).
The emulsifier may comprise, or be, one or more alkyl glucosides. As alkyl
glucosides that may be used in the invention, mention may be made of capryl
glucoside, caprylyl glucoside, lauryl glucoside, cocoyl glucoside, hexyl glucoside,
isooctyl glucoside, decyl glucoside and/or undecyl glucoside. These alkyl glucosides
30 may or may not be oxyalkylenated (and more particularly ethoxylated or nonethoxylated).
The emulsion may comprise a combination of at least two emulsifiers, in
particular each of which may independently be as described above.
Preferably, the combination of the at least two emulsifiers comprises a non35 ethoxylated sorbitan as defined above and an ethoxylated sorbitan comprising between
5 and 20 ethylene oxide groups, as described above.
In addition or as an alternative to the use of one or more nonionic surfactants
(for example as described above), the emulsion according to the invention may
comprise, as emulsifier, at least one protective colloidal agent. Protective colloidal
40 agents are emulsifiers that are well known to those skilled in the art. For the purposes
14
of the present invention, they refer to the group consisting of polyvinyl alcohol,
polyvinyl acetate and notably partially hydrolyzed polyvinyl acetate, cellulose esters
and xanthan gums.
Thus, preferably, the protective colloidal agent in the emulsion according to
5 the invention is chosen from the group consisting of polyvinyl alcohols, partially
hydrolyzed polyvinyl acetates, cellulose esters, xanthan gums and mixtures thereof.
The hydrolyzed polyvinyl acetate is preferably hydrolyzed to a degree of from 5 mol%
to 85 mol%, preferably from 5 mol% to 75 mol%.
The at least one emulsifier of the emulsion according to the invention may
10 consist of at least one protective colloidal agent.
More particularly, the emulsion according to the invention may comprise, as
the at least one emulsifier, at least one polyvinyl alcohol and/or at least one hydrolyzed
polyvinyl acetate, optionally in combination with one or more surfactants, in particular
one or more nonionic surfactants as described above. The at least one emulsifier of the
15 emulsion according to the invention may consist of at least one polyvinyl alcohol
and/or at least one hydrolyzed polyvinyl acetate, optionally in combination with one
or more surfactants, in particular one or more nonionic surfactants as described above.
The emulsifier according to the invention may consist of at least one nonionic
surfactant, in particular at least one nonionic surfactant as described above, and
20 optionally at least one protective colloidal agent.
The emulsifier according to the invention may consist of at least one protective
colloidal agent and optionally at least one nonionic surfactant, in particular at least one
nonionic surfactant as described above.
Alternatively, the emulsion according to the invention may be free of polyvinyl
25 alcohol. The emulsion according to the invention may be free of partially hydrolyzed
polyvinyl acetate, and may more particularly be free of polyvinyl acetate.
More particularly, the emulsion according to the invention may be free of
protective colloidal agent. This notably makes it possible to reduce the time for the
industrial preparation of the emulsion, since the protective colloidal agent (notably
30 polyvinyl acetate) which is in solid form requires a prior dissolution step, and makes
it possible to minimize the risks associated with the handling of powders. Furthermore,
the presence in the emulsion of a colloidal protective agent may increase the viscosity
of the emulsion, which may be undesirable for certain applications.
The emulsion according to the invention may be free of cellulose ester, more
35 particularly cellulose derivatives. The emulsion may be free of xanthan gum.
The emulsifier may be present in the emulsion according to the invention in an
amount ranging from 0.1% to 10% by weight, preferably from 0.5% to 5% by weight,
relative to the total weight of the emulsion. In particular, the emulsion may comprise
the emulsifier in an amount of from 0.1% to 0.5% by weight, or from 0.5% to 1% by
40 weight, or from 1% to 2% by weight, or from 2% to 3% by weight, or from 3% to 4%
15
by weight, or from 4% to 5% by weight, or from 5% to 6% by weight, or from 6% to
7% by weight, or from 7% to 8% by weight, or from 8% to 9% by weight, or from 9%
to 10% by weight, relative to the total weight of the emulsion.
The emulsion according to the invention may comprise the at least one nonionic
5 surfactant in an amount of from 0.1% to 10% by weight, preferably from 0.5% to 5%
by weight, relative to the total weight of the emulsion. In particular, the emulsion may
comprise the nonionic surfactant in an amount of from 0.1% to 0.5% by weight, or
from 0.5% to 1% by weight, or from 1% to 2% by weight, or from 2% to 3% by weight,
or from 3% to 4% by weight, or from 4% to 5% by weight, or from 5% to 6% by
10 weight, or from 6% to 7% by weight, or from 7% to 8% by weight, or from 8% to 9%
by weight, or from 9% to 10% by weight, relative to the total weight of the emulsion.
The emulsion according to the invention may comprise the at least one
protective colloidal agent in an amount of from 0.1% to 10% by weight, preferably
from 0.5% to 5% by weight, relative to the total weight of the emulsion. In particular,
15 the emulsion may comprise the nonionic surfactant in an amount of from 0.1% to 0.5%
by weight, or from 0.5% to 1% by weight, or from 1% to 2% by weight, or from 2%
to 3% by weight, or from 3% to 4% by weight, or from 4% to 5% by weight, or from
5% to 6% by weight, or from 6% to 7% by weight, or from 7% to 8% by weight, or
from 8% to 9% by weight, or from 9% to 10% by weight, relative to the total weight
20 of the emulsion.
The emulsion according to the invention may also comprise one or more
additives intended to give the final composition particular properties/characteristics.
These additives will ideally be present for the final polymerization or
copolymerization.
25 The additive may be chosen from the group consisting of antifoams, chaintransfer agents, chain extenders, pH regulators, plasticizers and mixtures thereof.
The additive(s) are preferably in an amount of from 0.1% to 10% by weight,
preferably from 1% to 5% by weight, relative to the total weight of the emulsion.
Preferably, the emulsion according to the invention comprises one or more
30 plasticizers, preferably chosen from the group consisting of aliphatic esters, for
instance phthalates, adipates, benzoates, hydrogenated derivatives of these molecules
and mixtures thereof. In particular, the plasticizer may be diisononylcyclohexane,
diisononyl cyclohexanedicarboxylate, and a mixture thereof. The plasticizer(s) may be
present in the emulsion in an amount of from 1% to 5% by weight relative to the total
35 weight of the emulsion.
Advantageously, the emulsion according to the invention may consist
essentially of, or consist of, the at least one organic peroxide, the at least one
emulsifier, the at least one antifreeze, water and optionally one or more additives as
described above. The term “the emulsion consists essentially of constituents” means
40 that the total amount of these constituents represents at least 90% by weight, preferably
16
at least 95% by weight, more preferentially at least 98% by weight of the total weight
of the emulsion. The expression “consists of” does not exclude the presence of
impurities present in trace amounts in the emulsion (for example, in an amount of less
than or equal to 1% by weight relative to the total weight of the emulsion), for example
5 impurities introduced with the organic peroxide. Thus, in certain embodiments, the
emulsion according to the invention may comprise an organic solvent, in an amount
of less than or equal to 1% by weight relative to the total weight of the emulsion.
In other embodiments, the emulsion according to the invention may comprise
an organic solvent, for example in an amount of less than or equal to 20% by weight
10 relative to the total weight of the emulsion. In the present text, the term “organic
solvent” means organic solvents which have a solubility in water of less than 1% by
weight at 0°C. The emulsion according to the invention may consist essentially of, or
consist of, the at least one organic peroxide, the at least one emulsifier, the at least one
antifreeze, water, an organic solvent (preferably in an amount of less than or equal to
15 20% by weight relative to the total weight of the emulsion) and optionally one or more
additives as described above.
The emulsion according to the invention may consist essentially of, or consist
of, the at least one organic peroxide, the at least one emulsifier, the at least one
antifreeze and water (the emulsion being free of methanol and ethanol).
20 Preferably, the emulsion according to the invention has a flowability (or flow
time) at 5°C, measured via a consistometric cup technique, of less than or equal to 200
seconds, more preferentially less than or equal to 150 seconds, and even more
advantageously less than or equal to 100 seconds. The flowability may be measured
according to the standard DIN 53211, with a viscosity cup diameter of 4 mm and a
25 temperature of 5°C.
Particularly advantageously, the emulsion according to the invention has an
average droplet size of less than or equal to 10 µm, preferably less than or equal to 7
µm and more particularly advantageously less than or equal to 6 µm. Advantageously,
the emulsion according to the invention has a maximum droplet size of less than or
30 equal to 20 µm, more preferentially less than or equal to 18 µm, and even more
advantageously less than or equal to 15 µm. The droplet size (average and maximum)
may be determined via conventional means using the light scattering technique. The
measurements may be taken using a Malvern Master Sizer 2000® device at room
temperature.
35 More advantageously, the emulsion according to the invention has the
abovementioned droplet sizes during the storage period, for example for a period of at
least three months.
Preferably, the concentration of organic peroxide in the emulsion is
homogeneous. The term “homogeneous concentration” means that the difference
40 between the concentrations of peroxide (as mass percentages) at the top and bottom of
17
the emulsion is less than 3%. The organic peroxide concentration is measured by
HPLC on a sample taken from the top of the emulsion and another from the bottom of
the emulsion.
More advantageously, the emulsion according to the invention is homogeneous
5 during the storage period, for example for a period of at least three months.
Preparation of the emulsion
The invention also relates to a process for preparing the emulsion according to
the invention.
10 The preparation process according to the invention comprises a step of mixing
the at least one organic peroxide, the at least one emulsifier, the at least one antifreeze
and water. This step may also comprise the above mixing with other constituents of
the emulsion when the emulsion comprises them, for example mixing with one or more
additives (such as one or more plasticizers, etc.) as described in the previous section.
15 The mixing may be performed in one step (the constituents all being added to the
mixture simultaneously) or in several steps (a premix of some constituents first being
made, followed by the addition of other constituents).
The process also comprises a step of emulsifying the mixture. The steps of
mixing of the constituents of the emulsion and of emulsifying may be simultaneous.
20 Alternatively, the emulsifying step may be performed successively to a first step of
mixing the constituents of the emulsion.
The emulsion according to the invention may be prepared by dispersing at least
the emulsifier and the antifreeze, and also optionally one or more additives, in water
so as to obtain a homogeneous aqueous phase, then by adding one or more organic
25 peroxides to said aqueous phase, the whole being then emulsified in the course of an
emulsification step at a temperature preferably below 5°C, so as to limit premature
degradation of the peroxide, and more preferably below -5°C. Alternatively, the
emulsifier or one or more of the emulsifiers may be dissolved in the organic
peroxide(s) before being added to the aqueous phase.
30 The abovementioned steps may be performed in the particular order indicated
above, or in a different order.
The temperature at which the emulsion is prepared is not critical, but it must
be sufficiently low to avoid a high rate of decomposition of the organic peroxide,
which would result in a loss of titer. The temperature chosen depends on the organic
35 peroxide. It is, for example, between 15 and 10°C, preferably from -10 to 5°C.
Preferably, the mixing and emulsifying steps are performed at the same temperature,
preferably within the ranges mentioned above.
Deionized water or distilled water is preferably used to prepare the aqueous
emulsion.
18
The emulsifying step of the process according to the invention is preferably
performed with a high-shear mixer to optimally divide and/or homogenize the
peroxide in the aqueous phase. Examples that may be mentioned include mechanically
rotating blade and anchor agitators, impeller agitators, i.e. one or more agitators
5 mounted on a common shaft, turbine agitators, i.e. those including baffles attached to
the mixing vessel or adjacent to the agitator members. Colloidal mills and
homogenizers may also be used.
According to one variant of the process according to the invention, an
ultrasonic mixer or a rotor-stator mixer may be used for the emulsification.
10 Following the preparation of the emulsion, the steps of pumping and
introducing the emulsions into a polymerization reactor should generally be performed
as quickly as possible. Accordingly, the peroxide emulsions should advantageously
have a low viscosity. Thus, the organic peroxide emulsions according to the invention
preferably have a dynamic viscosity range, at -10°C and at a shear rate of 100 s-1
, of
15 less than or equal to 850 mPa.s, more preferably less than or equal to 700 mPa. s, more
preferentially less than or equal to 500 mPa.s, immediately after production (the
viscosities are measured, for example, according to the standard DIN 53019 with
apparatus of the Haake VT550 Viscotester type, at -10°C and for a shear rate of 100 s1
).
20 Their flowability, measured by means of a consistometric cup technique, is
advantageously less than or equal to 200 seconds, more preferentially less than or equal
to 170 seconds, and even more advantageously less than or equal to 100 seconds
(measured, for example, according to the standard DIN 53211, with a viscosity cup
diameter of 4 mm and a temperature of 5°C).
25 The average droplet size of the emulsion is preferably less than or equal to 10
µm, more preferably less than or equal to 7 µm and more particularly advantageously
less than or equal to 6 µm. Advantageously, the maximum droplet size of the emulsion
is less than or equal to 20 µm, more preferentially less than or equal to 18 µm, and
even more advantageously less than or equal to 15 µm. The droplet size (average and
30 maximum) may be determined via conventional means using the light scattering
technique and the measurements may be taken using a Malvern Master Sizer 2000®
device at room temperature.
Use
35 The present invention also relates to the use of the emulsion as described above
for the polymerization or copolymerization of one or more ethylenically unsaturated
monomers, in particular of one or more vinyl monomers, preferably halogenated vinyl
monomers, and more preferentially vinyl chloride.
19
As examples of ethylenically unsaturated monomers that may be used in the
invention, mention may be made of acrylates, vinyl esters, vinyl halide monomers,
vinyl ethers, butadiene and/or aromatic vinyl compounds such as styrene.
Preferably, the ethylenically unsaturated monomers are chosen from the group
5 consisting of vinyl halide monomers (i.e. halogenated vinyl monomers), and more
preferentially the ethylenically unsaturated monomers are vinyl chloride.
The invention also relates to a process for preparing a halogenated vinyl
polymer, comprising a step of polymerization or copolymerization of one or more
ethylenically unsaturated monomers in the presence of an emulsion as described
10 above. The ethylenically unsaturated monomers may be as described above and are
more preferentially vinyl chloride. The halogenated vinyl polymer prepared is
preferably a poly(vinyl chloride).
The polymerization of the ethylenically unsaturated monomer(s), preferably
the polymerization of the vinyl chloride monomer, advantageously takes place in
15 suspension, preferably at an initiation temperature ranging from 45°C to 70°C.
The emulsion may be added directly to the polymerization reactor or may be
premixed with other organic peroxides, water, polyvinyl alcohol and/or other additives
prior to introducing this mixture into the polymerization reactor.
20 Polymer
Another subject of the present invention relates to a halogenated vinyl polymer
obtained (or which may be obtained) by polymerization of at least one ethylenically
unsaturated monomer, as described above, in the presence of the emulsion according
to the invention as described above. The polymerization may be as described in the
25 preceding section.
Preferably, the invention relates to a poly(vinyl chloride) obtained (or which
may be obtained) by polymerization of vinyl chloride in the presence of the emulsion
according to the invention.
The invention also relates to a halogenated vinyl polymer obtained (or which
30 may be obtained) via a preparation process as described above.
Such halogenated vinyl polymers have the advantage of having a low hard
grain content. The hard grain content may be determined as described in the article by
O. Leachs, in Kunststoffe, Vol. 50(4), 1960 pages 227-234.
35 Examples
The examples that follow illustrate the invention without limiting it.
The following emulsions were prepared (the amounts indicated in the tables
below are expressed as mass percentages relative to the total weight of the emulsion):
[Table 1]
Composition No. 1 2 3 4 5
20
PVA 1.2 1.2 1.9 1.9 1.9
Methanol 11.3 9.9 9.4
Ethanol 11.3 9.3
Propane-1,2-diol 3.2 3.3 6.5 6.9 6.5
Luperox 225 60.0 59.7 59.6 59.7 50.2
Demineralized
water
qs 100 qs 100 qs 100 qs 100 qs 100
[Table 2]
Composition No. 6 7 8 9 10
PVA 1.9 1.2 1.2
Surfaline LG15 1.6 1.5
Ethanol 9.3 13.5
Propane-1,2-diol 6.5 21.6 21.4 21.4 6.6
Luperox 225 50.2 49.8 50.1 50.1 50.1
Demineralized
water
qs 100 qs 100 qs 100 qs 100 qs 100
qs 100 = quantity sufficient to reach 100% of the weight of the emulsion.
5 The nature of the compounds used is indicated below:
- Luperox 225: di-sec-butyl peroxydicarbonate;
- Surfaline LG15: nonionic surfactant, unsaturated C16–C18 and C18 glycerol
mono-/diester, polyethoxylated (15 units);
- PVA: polyvinyl acetate with a degree of hydrolysis of 72.5 mol% (Alcotex
10 72.5).
Emulsions 7, 8 and 9 correspond to emulsions according to the invention, and
emulsions 1, 2, 3, 4, 5, 6 and 10 are comparative emulsions.
The emulsions were prepared as described below.
15 The aqueous phase containing the emulsifier, antifreeze and water was stirred
at between 500 and 1000 revolutions per minute (rpm) and maintained at -5°C
(Celsius).
The organic peroxides were added gradually to the reactor containing this
mixture. Stirring was continued for three minutes at 2000 rpm. The whole was then
20 stirred vigorously with an “Ultra-Turrax S-25N 18G” blender for two minutes (except
for emulsion No. 8, which was stirred for six minutes) at 9500 rpm, then stirred with
a paddle at 1000 rpm for one minute. Each emulsification is made on 200 g in total.
The emulsions were then transferred into a plastic container, the container was
closed and the emulsions were stored at -20°C for the time indicated.
21
The flow time at 5°C (viscosity cup at 5°C), the average and maximum droplet
sizes, by volume, over a period of 6 months, and also the concentration of organic
peroxide at the top and bottom of the aqueous phase of the emulsion (as weight
percentages relative to the total weight of the aqueous phase) were determined, as
5 indicated below.
The flow time measurements are taken using consistometric cups according to
the standard DIN 53211 (viscosity cup diameter: 4 mm), which is well known to those
skilled in the art. The measurement is taken on 100 g of emulsion after conditioning at
+5°C. The flow time measurements are expressed in seconds and the accuracy is ±10%
10 of the indicated value.
The average droplet size and the maximum droplet size are determined via
conventional means using the light scattering technique. The measurements are taken
using a Malvern Mastersizer 2000® device at room temperature. The average droplet
size and the maximum droplet size are given with an accuracy of ± 0.5 µm
15 (micrometer).
After 6 months of storage at -20°C, a sample from the top of the emulsion
(taken from the first centimeter below the emulsion surface) and a sample from the
bottom of the emulsion (taken from the first centimeter from the bottom of the
emulsion) were taken and analyzed to determine the organic peroxide concentration.
20 The concentrations of organic peroxide in the aqueous phase were determined on a
Waters H-class UPLC machine with an accuracy of ± 1%.
The results are presented in the tables below.
[Table 3]
Composition No. 1 2 3 4 5
After preparation of the emulsion (T0)
Viscosity cup at
5°C (s)
108 142 262 290 48
Average
droplet size (µm)
3.3 2.4 2.5 2.4 2.9
Maximum
droplet size (µm)
8.7 15.1 6.6 15.1 7.6
At T0 + 1 month
Average
droplet size (µm)
Not
measurable
due to
demixing,
appearance
of pressure
7.6 10.4 9.1
Not
measurable
due to
demixing,
appearance
of pressure
Maximum
droplet size (µm)
26.3 34.7 26.3
22
in the
container
in the
container
At T0 + 2 months
Average
droplet size (µm)
Not
measurable
due to
demixing
Not
measurable
due to
demixing,
appearance
of pressure
in the
container
Not
measurable
due to
demixing,
appearance
of pressure
in the
container
Not
measurable
due to
demixing,
appearance
of pressure
in the
container
Not
measurable
due to
demixing
Maximum
droplet size (µm)
[Table 4]
Composition No. 6 7 8 9 10
After preparation of the emulsion (T0)
Viscosity cup at
5°C (s)
57 100 90 23
Not
measurable
due to
demixing
after a
period of
about 2
hours
Average
droplet size (µm)
2 2.5 1.9 2.1
Maximum
droplet size (µm)
5.8 6.6 5.8 5.8
At T0 + 1 month
Average
droplet size (µm)
Not
measurable
due to
demixing,
appearance
of pressure
in the
container
Not
measured
Not
measured
2.1
Not
measurable
due to
demixing
Maximum
droplet size (µm)
5.8
At T0 + 2 months
Average
droplet size (µm)
Not
measurable
due to
demixing
5.2 3.2 2.2
Not
measurable
due to
demixing
Maximum
droplet size (µm)
13.2 15.1 5.8
At T0 + 3 months
Average
droplet size (µm)
Not
measurable
5.9 5.8 2.2
Not
measurable
23
Maximum
droplet size (µm)
due to
demixing
15.1 15.1 6.6
due to
demixing
At T0 + 4 months
Average
droplet size (µm)
Not
measurable
due to
demixing
6.3 6.2 2.2
Not
measurable
due to
demixing
Maximum
droplet size (µm)
17.4 17.4 6.6
At T0 + 5 months
Average
droplet size (µm)
Not
measurable
due to
demixing
6.6 6.6 2.2
Not
measurable
due to
demixing
Maximum
droplet size (µm)
17.4 17.4 6.6
At T0 + 6 months
Average
droplet size (µm)
Not
measurable
due to
demixing
7.2 6.9 2.2
Not
measurable
due to
demixing
Maximum
droplet size (µm)
20.0 20.0 6.6
Concentration at
the top (%)
47.70% 48.30% 48.90%
Concentration at
the bottom (%)
49.60% 50.30% 49.10%
It is seen that emulsions 7 and 8 according to the invention are more stable than
emulsions 1 to 6. Indeed, the latter undergo demixing after only 1 or 2 months of
storage, whereas emulsions 7 and 8 remain stable over a period of at least 6 months.
5 The appearance of pressure in the container of emulsions 1 to 6 is also observed, which
is a sign of decomposition of the Luperox 225. In addition, the average droplet size of
emulsions 7 and 8 remains small over a period of at least 6 months. Furthermore, after
6 months, the concentrations of organic peroxide at the top and bottom of the aqueous
phase of emulsions 7 and 8 are similar: emulsions 7 and 8 are still homogeneous after
10 6 months of storage.
Emulsion 9 according to the invention is also more stable than the comparative
emulsion 10, for which phase separation is observed as early as 2 hours after its
preparation. On the other hand, emulsion 9 according to the invention maintains its
stability over a period of at least 6 months and retains a low average and maximum
15 droplet size over this period. In addition, after 6 months, emulsion 9 has remained
homogeneous, the concentrations of organic peroxide at the top and bottom of the
aqueous phase being similar.
24
The viscosity cup values of the emulsions according to the invention are
relatively low and are suitable for a polymerization application.

WE CLAIM:
1. An organic peroxide emulsion comprising:
- at least one organic peroxide comprising di-sec-butyl
5 peroxydicarbonate;
- at least one emulsifier;
- at least one antifreeze; and
- water;
said emulsion being free of methanol and ethanol.
10
2. The emulsion as claimed in claim 1, in which the at least one antifreeze
is an alcohol, preferably chosen from the group consisting of
monoalcohols, diols, triols and mixtures thereof.
15 3. The emulsion as claimed in claim 1 or 2, in which the at least one
antifreeze is chosen from the group consisting of ethylene glycol, 2-
propanol, 1-propanol, propane-1,2-diol, propane-1,3-diol, glycerol,
butan-1-ol, butan-2-ol, butan-1,3-diol, butan-1,4-diol, diethylene
glycol, triethylene glycol and mixtures thereof.
20
4. The emulsion as claimed in one of claims 1 to 3, in which the at least
one antifreeze comprises, preferably consists of, propane-1,2-diol.
5. The emulsion as claimed in one of claims 1 to 4, in which the at least
25 one antifreeze is present in an amount of from 10% to 40% by weight,
preferably from 15% to 25% by weight, relative to the total weight of
the emulsion.
6. The emulsion as claimed in one of claims 1 to 5, in which the at least
30 one organic peroxide consists of di-sec-butyl peroxydicarbonate.
7. The emulsion as claimed in one of claims 1 to 6, in which the di-secbutyl peroxydicarbonate is present in an amount of from 30% to 80%
by weight, preferably from 40% to 60% by weight, more preferentially
35 from 45% to 60% by weight, relative to the total weight of the emulsion.
8. The emulsion as claimed in one of claims 1 to 7, in which the at least
one emulsifier comprises a nonionic surfactant, preferably chosen from
the group consisting of oxyalkylenated fatty alcohols, oxyalkylenated
40 fatty acids, oxyalkylenated plant or animal oils, polysorbates, sorbitan
26
esters, non-oxyalkylenated alkyl glucosides, oxyalkylenated alkyl
glucosides and mixtures thereof.
9. The emulsion as claimed in one of claims 1 to 8, in which the at least
5 one emulsifier comprises at least one protective colloidal agent,
preferably at least one polyvinyl alcohol and/or hydrolyzed polyvinyl
acetate.
10. The emulsion as claimed in one of claims 1 to 7 or 9, in which the at
10 least one emulsifier consists of at least one protective colloidal agent,
preferably at least one polyvinyl alcohol and/or hydrolyzed polyvinyl
acetate.
11. The emulsion as claimed in one of claims 1 to 8, which is free of
15 polyvinyl alcohol and of hydrolyzed polyvinyl acetate.
12. A process for preparing an emulsion as claimed in one of claims 1 to
11, comprising the following steps:
- mixing the at least one organic peroxide, the at least one emulsifier,
20 the at least one antifreeze and water; and
- emulsifying the mixture.
13. The use of the emulsion as claimed in one of claims 1 to 11, for the
polymerization or copolymerization of one or more ethylenically
25 unsaturated monomers, in particular vinyl monomers, preferably
halogenated vinyl monomers, and more preferentially vinyl chloride.
14. A halogenated vinyl polymer obtained by polymerization of at least one
ethylenically unsaturated monomer in the presence of the emulsion as
30 claimed in one of claims 1 to 11.