The present invention relates to a composition comprising at least one organic
peroxide, at least one emulsifier, hydrogen peroxide and water.
The invention also relates to the use of a composition as defined above for the
polymerization or copolymerization of one or more ethylenically unsaturated
10 monomers, preferably halogenated ethylenically unsaturated monomers, and more
preferentially vinyl chloride.
The present invention also relates to a halogenated vinyl polymer obtained by
polymerization or copolymerization of at least one halogenated ethylenically
unsaturated monomer in the presence of at least one composition as defined previously.
15 Organic peroxides, in liquid or solid form, are commonly used as initiators
for the polymerization of ethylenically unsaturated monomers for the synthesis of
various types of polymers. The organic peroxides may be peroxydicarbonates,
peroxyesters or diacyl peroxides, peroxyketals, monoperoxycarbonates or dialkyl
peroxides.
20 However, their use frequently presents a certain number of problems.
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 increase in the storage temperature, certain organic peroxides may
25 undergo a self-accelerating exothermic decomposition capable of resulting in violent
explosions and relatively serious fires. In addition, under these conditions, some of
these organic peroxides can release combustible vapors that can react 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
30 terms of safety during the storage and transportation of organic peroxides.
In order to overcome these drawbacks, organic peroxides are notably
packaged in the form of aqueous emulsions based on antifreezes. Thus, the presence
of water makes it possible both to absorb and to dissipate the energy generated in the
event of possible exothermic decompositions of organic peroxides, while the role of
35 the antifreeze is to keep the emulsion in liquid form, at temperatures much lower than
0°C, for example at temperatures below -10°C, or even generally below -15°C, which
3
makes it possible to prevent and/or limit the risks of an involuntary exothermic
decomposition of the organic peroxides during storage and transportation operations.
The aqueous emulsions generally also contain at least one emulsifier having
the advantage of lowering the interfacial tension between the aqueous phase and the
5 organic peroxide for the purpose of facilitating the dispersion of the peroxide in the
form of droplets and of maintaining the size of said droplets over time. Thus the role
of the emulsifier is to stabilize the peroxide droplets in the aqueous phase. This is
because, over time, the peroxide droplets can agglomerate together, bringing about an
increase in their average size and in their maximum size which can result, in some
10 cases, in total or partial phase separation and consequently in overall destabilization of
the emulsion.
Moreover, in addition to these safety considerations due to this destabilization
phenomenon, the use of inhomogeneous aqueous organic peroxide emulsions as
polymerization initiator in an emulsion or suspension of ethylenically unsaturated
15 monomers can also generate points of heterogeneity within the final polymeric product.
These heterogeneities generally result in the presence of particles of compact grains
which are polymer particles that are poorly gelled during the melt processing
(phenomenon referred to as “fish-eyes”). However, the presence of hard grains
opacifies the material obtained which will have an impact on its transparency, which
20 may become an essential requirement depending on the applications considered, in
particular in medical applications, and/or on its mechanical properties.
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 corresponding to their transportation and storage before being used as
25 polymerization initiators, and also for reasons linked to the quality of the product
obtained.
Aqueous organic peroxide emulsions generally comprise, as antifreeze
agents, one or more alcohols that are soluble in water at room temperature and have a
low molecular weight, such as methanol or ethanol, in particular methanol. The amount
30 of the antifreeze agent required to ensure a liquid emulsion at a given temperature
below 0°C depends on its molecular weight. The amount of methanol required is
therefore less than the amount of ethanol. At the same time, the volatility of alcohols
decreases with molecular weight. In order to reduce the risk related to the flash point
of the emulsion, it will be necessary to choose an alcohol with a higher molecular
35 weight. To maintain the melting point of the emulsion at the same temperature, it is
necessary to significantly increase the amount of alcohol in the aqueous phase, which
leads to problems of stability of the emulsion and increases the amount of organic
4
molecules found in the effluents from the polymerization process. In addition, such
antifreezes have the disadvantage of being volatile and of generating volatile organic
compounds (VOCs) which may prove to be harmful to the health of the operators, in
particular during the various steps of handling the aqueous organic peroxide emulsions
5 used for the synthesis of polymers obtained from one or more ethylenically unsaturated
monomers. In other words, the presence of these antifreezes may also pose health
safety problems when handling aqueous organic peroxide emulsions.
Thus, one of the objectives of the present invention is to provide a
composition in the form of an aqueous organic peroxide emulsion which is stable and
10 homogeneous over time, intended to be used as polymerization initiators, which does
not have the drawbacks described previously in terms of the safety and quality of the
product obtained.
In other words, one of the aims of the present invention is to provide a
composition based on organic peroxide which poses fewer problems in terms of safety,
15 in particular in terms of health, for operators than the aqueous organic peroxide
emulsions customarily used for the synthesis of polymers obtained from ethylenically
unsaturated monomers while being capable of being stable and homogeneous over time
and having only a reduced amount of organic molecules in the aqueous phase.
One subject of the present invention is therefore in particular a composition
20 comprising one or more organic peroxides in a content of 20% to 70% by weight, one
or more emulsifiers, optionally one or more antifreeze agents, hydrogen peroxide and
water.
The composition according to the invention thus has the advantage of posing
fewer safety problems, in particular in terms of health, for operators than the aqueous
25 organic peroxide emulsions conventionally used during the synthesis of polymers
obtained from ethylenically unsaturated monomers.
Specifically, the composition according to the invention generates fewer
volatile organic compounds (VOCs) than the aqueous organic peroxide emulsions
conventionally used in the prior art, and also a reduced amount of organic molecules
30 in the aqueous effluents from the polymerization process.
Furthermore, the composition according to the invention also has the
advantage of being stable and homogeneous for a period of time which may be one
month at a temperature strictly below 0°C, preferably below -5°C, more preferentially
below -10°C.
35 In addition, the composition according to the invention has a low viscosity,
which allows a short flow time, which makes it possible to facilitate the steps of
5
unloading of the emulsion into intermediate storage silos, pumping and introducing the
organic peroxide emulsion into a polymerization reactor.
Furthermore, the composition according to the invention may have an average
droplet size suitable for the application. Thus, the composition according to the
5 invention can be safely transported and stored in polymer production units and lead to
polymeric materials of good quality.
Another subject of the invention is the use of the composition as defined above
for the polymerization or the copolymerization of one or more ethylenically
unsaturated monomers, in particular one or more vinyl monomers, preferably
10 halogenated vinyl monomers, and more preferentially vinyl chloride.
The composition according to the invention can thus be used as
polymerization initiators for the synthesis of polymers or of copolymers obtained from
one or more ethylenically unsaturated monomers.
Thus the composition is compatible with the polymerization or
15 copolymerization of ethylenically unsaturated monomers, preferably vinyl monomers,
more preferentially halogenated vinyl monomers.
In addition, the invention also relates to a halogenated vinyl polymer obtained
by polymerization or copolymerization of at least one halogenated ethylenically
unsaturated monomer in the presence of the composition as defined above.
20 Other features and advantages of the invention will emerge more clearly on
reading the description and the examples that follow.
In what will follow and unless otherwise indicated, the limits of a range of
values are included in this range.
The expression “at least one” is equivalent to the expression “one or more”.
25
Composition
The composition according to the invention comprises 20% to 70% by weight
of one or more organic peroxides.
30 Preferably, the organic peroxide(s) is or are chosen from the group consisting
of peroxydicarbonates, peroxyesters, diacyl peroxides, peroxyketals,
monoperoxycarbonates, dialkyl peroxides and mixtures thereof.
The organic peroxides may be peroxydicarbonates, preferably chosen from
the group consisting of di-sec-butyl peroxydicarbonate, dibutyl peroxydicarbonate,
35 diisopropyl peroxydicarbonate, bis(3-methoxybutyl) peroxydicarbonate, bis(isobutyl)
peroxydicarbonate, dineopentyl peroxydicarbonate, bis[2-(2-methoxyethoxy)ethyl]
peroxydicarbonate, bis(3-methoxy-3-methylbutyl) peroxydicarbonate , bis(2-
6
ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, bis(1-
methylheptyl) peroxydicarbonate, and mixtures thereof.
Preferably, the peroxydicarbonate is chosen from the group consisting of di(2-
ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate and a mixture thereof.
5 The organic peroxides may also be peroxyesters, preferably chosen from the
group consisting of tert-amyl peroxypivalate, tert-butyl peroxypivalate, tert-butyl
peroxyisobutyrate, α-cumyl peroxyneodecanoate, α-cumyl peroxyneoheptanoate,
2,4,4-trimethylpentyl-2-peroxyneodecanoate, tert-butyl peroxyneoheptanoate, 2,5-
dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, tert-amyl peroxy-2-ethylhexanoate,
10 tert-butyl peroxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-
ethylhexanoate, tert-amyl peroxyneodecanoate, tert-butyl peroxyneodecanoate,
1,1,3,3-tetramethylbutyl peroxypivalate, 3-hydroxy-1,1-dimethylbutyl
peroxyneodecanoate and mixtures thereof.
The organic peroxides may be diacyl peroxides, preferably chosen from the
15 group consisting of diisobutyroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide,
di(2-ethylhexanoyl) peroxide, and also asymmetric peroxides such as isobutyroyl
octanoyl peroxide, isobutyroyl decanoyl peroxide, isobutyroyl lauroyl peroxide, 2-
ethylbutanoyl decanoyl peroxide, and mixtures thereof.
Preferably, the diacyl peroxides are chosen from the group consisting of
20 diisobutyroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, and a mixture thereof.
The organic peroxides may be peroxyketals, preferably chosen from the group
consisting of 1,1-di(tert-amylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)-3,3,5-
trimethylcyclohexane), 2,2-bis(4,4-di(tert-butylperoxy)cyclohexyl)propane, 1,1-
di(tert-butylperoxy)cyclohexane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane
25 and a mixture thereof, and is preferably 1,1-di(tert-amylperoxy)cyclohexane.
The organic peroxides may be monoperoxycarbonates, preferably chosen
from the group consisting of OO-tert-butyl O-isopropyl monoperoxycarbonate (TBIC),
OO-tert-amyl O-isopropyl monoperoxycarbonate (TA-IPC), OO-tert-butyl O-(2-
ethylhexyl) monoperoxycarbonate (TBEC) and OO-tert-amyl O-(2-ethylhexyl)
30 monoperoxycarbonate.
The organic peroxides may be dialkyl peroxides preferably chosen from the
group consisting of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl cumyl
peroxide, di-tert-amyl peroxide, di-tert-butyl peroxide and mixtures thereof.
Preferably, the organic peroxides are chosen from the group consisting of
35 peroxydicarbonates, peroxyesters, diacyl peroxides and mixtures thereof.
Preferably, the organic peroxides are chosen from the group consisting of
di(2-ethylhexyl) peroxydicarbonate, for example sold under the trade name Luperox®
7
223, di-sec-butyl peroxydicarbonate, for example sold under the trade name Luperox®
225, and tert-butyl peroxypivalate, for example sold under the trade name Luperox®
11.
Preferably, the organic peroxides are peroxydicarbonates, preferably di(2-
5 ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate and a mixture thereof,
more preferentially di(2-ethylhexyl) peroxydicarbonate.
The organic peroxides advantageously have a one hour half-life temperature
of less than 90°C.
Furthermore, the organic peroxides advantageously have a storage
10 temperature below 0°C.
The organic peroxides are advantageously liquid at the storage temperature,
preferably at a storage temperature below 0°C, measured at atmospheric pressure.
The organic peroxides are present in a content ranging from 20% to 70% by
weight, preferably in a content ranging from 40% to 60% by weight, and more
15 preferably from 45% to 60%, relative to the total weight of the composition.
The composition further comprises one or more emulsifiers.
Preferably, the emulsifier may be a protective colloid agent, in particular
chosen from the group consisting of: a partially hydrolyzed polyvinyl acetate (PVA),
a polyvinylpyrrolidone, a polyacrylate, a xanthan gum, a cellulose or a derivative
20 thereof, in particular a methyl cellulose, a carboxymethyl cellulose, and a starch or a
derivative thereof, and mixtures thereof, more preferentially is chosen from the group
consisting of a partially hydrolyzed polyvinyl acetate (PVA), a xanthan gum, a methyl
cellulose, a carboxymethyl cellulose and mixtures thereof, more preferentially is a
partially hydrolyzed polyvinyl acetate (PVA).
25 Preferably, the partially hydrolyzed polyvinyl acetate has a degree of
hydrolysis of from 50 to 75 mol%.
Preferably, the emulsifier may also be a nonionic surfactant and/or an ionic
surfactant.
Preferably, the emulsifier is a nonionic surfactant, preferably chosen from the
30 group consisting of oxyalkylenated (or alkoxylated) fatty alcohols, alkoxylated fatty
acids, oxyalkylenated (or alkoxylated) plant or animal oils (hydrogenated or not),
(alkoxylated or not) sorbitan esters, and mixtures thereof.
Preferably, the emulsifier(s) is/are chosen from the group consisting of:
- a nonionic surfactant, preferably chosen from the group consisting of
35 oxyalkylenated fatty alcohols, alkoxylated fatty acids, oxyalkylenated (or
alkoxylated) plant or animal oils (hydrogenated or not), (alkoxylated or not)
sorbitan esters, and mixtures thereof,
8
- a protective colloid agent, in particular a partially hydrolyzed polyvinyl
acetate (PVA), and
- mixtures thereof.
5 In a particularly preferred embodiment, the emulsifier is a mixture of a
protective colloid agent, in particular a partially hydrolyzed polyvinyl acetate, and of
a nonionic surfactant.
The oxyalkylene units are more particularly oxyethylene units (i.e. ethylene
oxide groups), oxypropylene units (i.e. propylene oxide groups), or a combination
10 thereof, preferably oxyethylene units or a combination of oxyethylene units and
oxypropylene units.
The emulsifier may be present in the composition according to the invention
in a content ranging from 0.1% to 10% by weight, preferably in a content ranging from
0.5% to 5% by weight, relative to the total weight of the composition.
15 The composition may further comprise one or more antifreeze agents.
Preferably, the antifreeze agent(s) is/are soluble in water at the storage
temperature.
For the purposes of the present invention, the expression "soluble in water at
the storage temperature" is understood to mean a compound having a solubility in
20 water measured at a temperature ranging from -25°C to 30°C of at least 0.1 gram/liter
(g/l) (measured when the compound introduced into the water results in a
macroscopically homogeneous and transparent solution being obtained).
Preferably, the antifreeze agent(s) has/have a molecular weight of less than
160 g/mol, preferably has/have a molecular weight of less than 100 g/mol.
25 Preferably, the antifreeze agent(s) is/are preferentially chosen from the group
consisting of monoalcohols, diols and triols.
Preferably, the antifreeze agent is chosen from the group consisting of C1-C6,
especially C2-C6, alcohols.
Preferably, the antifreeze agent is chosen from the group consisting of C1-C6
30 alcohols, preferentially chosen from the group consisting of methanol, ethanol,
ethylene glycol, isopropanol, n-propanol, propane-1,2-diol, propane-1,3-diol, glycerol,
butan-l-ol, butan-2-ol, butane-1,3-diol, diethylene glycol, triethylene glycol and
butane-1,4-diol and mixtures thereof, preferably ethanol.
The antifreeze agent is preferably present in the composition according to the
35 invention in a content of less than 25% by weight and preferably less than 15% by
weight relative to the total weight of the composition.
9
Preferably, the composition according to the invention contains less than 15%
by weight of ethanol relative to the total weight of the composition.
The composition according to the invention comprises hydrogen peroxide.
Preferably, the hydrogen peroxide is in liquid form.
5 Preferably, the hydrogen peroxide is present in a content ranging from 0.01%
to 15% by weight, more preferentially in a content ranging from 1% to 6% by weight,
relative to the total weight of the composition.
Preferably, when the composition comprises at least one antifreeze agent, the
weight ratio between the total content of antifreeze agent(s) and the total content of
10 hydrogen peroxide ranges from 0.1 to 10, more preferentially ranges from 0.5 to 5.
The composition according to the invention further comprises water,
preferably in a content ranging from 15% to 58.9% by weight, relative to the total
weight of the composition.
Preferably, the composition according to the invention comprises:
15 - 20% to 70% by weight of one or more organic peroxides chosen from the
group consisting of peroxydicarbonates, peroxyesters, diacyl peroxides, peroxyketals,
monoperoxycarbonates, dialkyl peroxides and mixtures thereof,
- one or more emulsifiers, preferably chosen from the group consisting of
nonionic surfactants, protective colloid agents and mixtures thereof,
20 - one or more antifreeze agents having a molecular weight of less than 160
g/mol, preferably a molecular weight of less than 100 g/mol, and soluble in water at
room temperature, preferentially chosen from the group consisting of C1-C6, especially
C2-C6, alcohols,
- hydrogen peroxide, and
25 - water.
Preferably, the composition according to the invention comprises:
- one or more organic peroxides chosen from the group consisting of
peroxydicarbonates, preferentially chosen from the group consisting of di(2-
ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate and a mixture thereof,
30 - one or more emulsifiers chosen from the group consisting of nonionic
surfactants, protective colloid agents and mixtures thereof,
- one or more antifreeze agents having a molecular weight of less than 160
g/mol, preferably a molecular weight of less than 100 g/mol, and soluble in water at
room temperature, preferentially chosen from the group consisting of C1-C6, especially
35 C2-C6, monoalcohols and dialcohols,
- hydrogen peroxide, and
- water.
10
Preferably, the composition according to the invention comprises:
- 20% to 70% by weight of one or more organic peroxides chosen from the
group consisting of peroxydicarbonates, preferentially di(2-ethylhexyl)
peroxydicarbonate,
5 - one or more emulsifiers chosen from the group consisting of nonionic
surfactants, protective colloid agents and mixtures thereof,
- one or more antifreeze agents chosen from the group consisting of C1-C6,
especially C2-C6, monoalcohols and dialcohols, in particular ethanol,
- hydrogen peroxide, and
10 - water.
The composition 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.
15 The additive may be chosen from the group consisting of antioxidants; UV
protection agents; processing agents, having the function of improving the final
appearance when it is used, such as fatty amides, stearic acid and the salts thereof,
ethylenebis(stearamide) or fluoropolymers; antifogging agents; antiblocking agents,
such as silica or talc; fillers, such as calcium carbonate, and nanofillers, for instance
20 clays; coupling agents such as silanes; crosslinking agents, such as peroxides other
than the organic peroxides according to the invention; antistatic agents; nucleating
agents; pigments; dyes; plasticizers; fluidizers and flame-retardant additives, such as
aluminum hydroxide or magnesium hydroxide.
The composition according to the invention may optionally contain one or
25 more additives including pH adjusters such as phosphate and citrate buffers, chelating
agents, biocides, for example fungicides, antiozonants, antioxidants, anti-degrading
agents, swelling agents and mold-release agents.
The composition according to the invention may also contain additives
customarily used to stabilize the organic peroxide or delay the decomposition thereof,
30 such as phlegmatizers (isododecane, mineral oil, etc.) or hydroperoxides.
These additives can be added in the amounts normally used and known to
those skilled in the art. These additives are generally used in contents of between 10
ppm and 10 000 ppm by weight relative to the weight of final polymer. The plasticizers,
the fluidizers and the flame-retardant additives can reach amounts well above 10 000
35 ppm.
Preparation of the composition
11
The composition according to the invention can be prepared by dispersing at
least the emulsifier, optionally one or more antifreeze agents, hydrogen peroxide, and
optionally one or more additives, in water to obtain a homogeneous aqueous phase and
5 then by adding one or more organic peroxides to said aqueous phase, the whole mixture
then being emulsified during an emulsification step.
The abovementioned steps may be performed in the particular order
prescribed, or in a different order. Apart from the particular successive steps of the
process for preparing the composition according to the invention, the preparation of
10 the emulsion is in no way different from the techniques and equipment well known to
those skilled in the art.
The temperature at which the emulsion is prepared is not critical, but it must
be sufficiently low to avoid a high rate of decomposition, which would result in a loss
of titer. The temperature chosen depends on the organic peroxide.
15 Preferably, the emulsification step is carried out at a temperature below 5°C
(Celsius).
Moreover, deionized water or distilled water is conventionally used to prepare
the aqueous emulsions.
Preferably, the emulsification step is performed with a high-shear mixer to
20 divide and/or homogenize the peroxide in the aqueous phase as much as possible.
Examples that may be mentioned include mechanically rotating blade and anchor
agitators, impeller agitators, i.e. one or more agitators 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.
25 According to one embodiment feature, the process according to the invention
is characterized in that an ultrasonic mixer or a rotor-stator mixer is used. Following
the preparation of the emulsion, the steps of pumping or transferring into another
container should be performed as quickly as possible. Accordingly, the peroxide
emulsions preferably have a low viscosity.
30
Preferably, the organic peroxide emulsions according to the invention have a
flowability or flow time measured by a consistometer cup technique of less than 200
seconds, preferentially less than 100 seconds (DIN 53211, viscosity cup diameter 4
mm, temperature 5°C). The subsequent polymerization or copolymerization steps are,
35 within the context of the present invention, no different from those of the prior art.
Use
12
The present invention also relates to the use of a composition as defined above
for the polymerization or copolymerization of one or more ethylenically unsaturated
monomers, in particular of one or more vinyl monomers, preferably halogenated vinyl
5 monomers, and more preferentially vinyl chloride.
Mention may be made, as ethylenically unsaturated monomers, of acrylates,
vinyl esters, vinyl halide monomers, vinyl ethers, butadiene or vinylaromatic
compounds, such as styrene.
Preferably, the ethylenically unsaturated monomers are chosen from the group
10 consisting of vinyl halide monomers (i.e. halogenated vinyl monomers), in particular
vinyl chloride or vinyl fluoride, and more preferentially vinyl chloride.
Preferably, the polymerization or copolymerization is carried out with a
suspension of the monomers to be polymerized.
The aqueous emulsion composition according to the invention can also be
15 used in applications such as polymer modification reactions, crosslinking reactions,
bulk polymerization reactions and curing processes as used in unsaturated polyester
resins.
In particular, the aqueous emulsion composition according to the invention
can also be used to modify the rheology of polymers, in particular of polypropylene.
20
Polymer
Another subject of the present invention relates to the polymer, preferably a
vinyl polymer, more preferentially a halogenated vinyl polymer, obtained by
25 polymerization or copolymerization of at least one ethylenically unsaturated monomer,
as defined previously, in the presence of the composition according to the invention as
defined above.
Preferably, the invention relates to the poly(vinyl chloride) obtained by
polymerization of vinyl chloride in the presence of the composition according to the
30 invention, in particular of the mixture of organic peroxides, as defined above.
In particular, the polymerization of the vinyl chloride monomer takes place in
suspension, preferably at an initiation temperature ranging from 45°C to 70°C.
The examples that follow serve to illustrate the invention without, however,
being limiting in nature.
13
EXAMPLES
Example 1
5 The following compositions A1, A2, A3, A4, A5, A6 and C1 are prepared
according to the same procedure.
The aqueous phase containing the emulsifier, namely the nonionic surfactant,
optionally the antifreeze agent, hydrogen peroxide and water is stirred between 500
10 and 1000 revolutions per minute (rpm) and maintained at -5°C (Celsius).
The organic peroxides are added gradually to the reactor containing this
mixture. Stirring is maintained for 3 minutes at 2000 rpm. The whole mixture is then
stirred vigorously using an Ultra-Turrax S-25N 18G machine for 2 or 8 minutes at
9500 rpm or 12 500 rpm, and then stirred using a paddle at 1000 rpm for 1 minute.
15 Each emulsification is performed on 200 g in total.
Tests performed:
The flow time measurements are taken using consistometer cups according to
20 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%
of the indicated value.
The average droplet size is determined via conventional means using the light
25 scattering technique.
The measurements are taken using a Malvern Mastersizer 2000® device at
room temperature. The average droplet size is given with an accuracy of ± 0.5 µm
(micrometer).
30 Compositions:
The amounts of the ingredients below are indicated as weight percentages
relative to the total weight of the composition in table 1 below:
[Table 1]
A1 A2 A3 A4 A5 A6 C1
Ultra-Turrax
14
Stirring time
(minutes)
8 2 2 2 2 2 2
Rotations per
minute
12500 9500 9500 9500 9500 9500 9500
Ethoxylated castor
oil
(Surfaline ®
OC23)
0.9 - - 0.9 0.9 - -
Tween® 80 0.8 0.8
Span® 80 1.1 - - 1.1 0.4 0.8 0.8
Alcotex (PVA) - 1.5 1.2 - - - -
Ethanol - 8.0 - - 10.4 - -
1,2-Propanediol 12 16.5
Hydrogen
peroxide
10 6.9 15.0 11.4 5.9 6.6 -
Di(2-ethylhexyl)
peroxydicarbonate
(Luperox ® 223)
60.0 59.8 59.1 60.1 56.1 - -
t-butyl
peroxypivalate
(75 wt% Luperox®
11 + 25 wt%
isododecane)
60 60
Water qs
100
qs
100
qs
100
qs
100
qs 100 qs 100 qs 100
Results:
At the time of production of the compositions
5 The results of average droplet size and of flow time at the time of production
of compositions A1, A2, A3, A4, A5, A6 and C1 are collated in table 2 below:
[Table 2]
A1 A2 A3 A4 A5 A6 C1
15
Average droplet
size (µm) at T0
4.2 2.0 5.8 7.5 2.3 1.3 1.0
Flow time
at T = +5°C (s)
22 183 96 22 26 54 92
The results show that the compositions according to the invention
(compositions A1, A2, A3, A4, A5 and A6) have a small average droplet size, despite
the presence of hydrogen peroxide in the emulsion.
5
Stability of the test compositions
The results of average droplet size determined over a period of time of one
month at -20°C of the compositions tested are collated in table 3 below:
10 Table 3:
A1 A2 A3 A4 A5 A6 C1
T +1
month
Average
droplet size
(µm)
4.0 2.6 6.0 7.5 2.3 1.3 1.1
The results show that the compositions according to the invention
(compositions A1, A2, A3, A4, A5 and A6), after one month of storage at -20°C, have
15 an average droplet size that is virtually unchanged from those measured at the time of
production of the composition. These emulsions are therefore stable over this period,
despite the presence of hydrogen peroxide in the emulsion. The emulsions according
to the invention therefore make it possible to reduce the amount of alcohol present in
the emulsion, while maintaining a liquid emulsion that is stable at -20°C.
16
CLAIMS
1. A composition comprising:
- 20% to 70% by weight of one or more organic peroxides;
5 - one or more emulsifiers,
- optionally one or more antifreeze agents,
- hydrogen peroxide and
- water.
2. The composition as claimed in claim 1, characterized in that the organic
10 peroxides are chosen from the group consisting of peroxydicarbonates, peroxyesters,
diacyl peroxides, peroxyketals, monoperoxycarbonates, dialkyl peroxides and
mixtures thereof, preferably chosen from the group consisting of peroxydicarbonates,
peroxyesters, diacyl peroxides and mixtures thereof, more preferentially
peroxydicarbonates.
15 3. The composition as claimed in claim 1 or 2, characterized in that the
organic peroxides are peroxydicarbonates chosen from the group consisting of di-secbutyl peroxydicarbonate, dibutyl peroxydicarbonate, diisopropyl peroxydicarbonate,
bis(3-methoxybutyl) peroxydicarbonate, bis(isobutyl) peroxydicarbonate, dineopentyl
peroxydicarbonate, bis[2-(2-methoxyethoxy)ethyl] peroxydicarbonate, bis(3-
20 methoxy-3-methylbutyl) peroxydicarbonate , bis(2-ethoxyethyl) peroxydicarbonate,
di(2-ethylhexyl) peroxydicarbonate, bis(1-methylheptyl) peroxydicarbonate, and
mixtures thereof, preferably chosen from the group consisting of di(2-ethylhexyl)
peroxydicarbonate, ethylhexyl), di-sec-butyl peroxydicarbonate and mixtures thereof.
4. The composition as claimed in any one of claims 1 to 3, characterized in
25 that the organic peroxides are peroxyesters chosen from the group consisting of tertamyl peroxypivalate, tert-butyl peroxypivalate, tert-butyl peroxyisobutyrate, α-cumyl
peroxyneodecanoate, α-cumyl peroxyneoheptanoate, 2,4,4-trimethylpentyl-2-
peroxyneodecanoate, tert-butyl peroxyneoheptanoate, 2,5-dimethyl-2,5-di(2-
ethylhexanoylperoxy)hexane, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-
30 ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-amyl
peroxyneodecanoate, tert-butyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl
peroxypivalate, 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate and mixtures
thereof.
5. The composition as claimed in any one of the preceding claims,
35 characterized in that the organic peroxides are diacyl peroxides chosen from the group
consisting of diisobutyroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, di(2-
ethylhexanoyl) peroxide, and also asymmetric peroxides such as isobutyroyl octanoyl
17
peroxide, isobutyroyl decanoyl peroxide, isobutyroyl lauroyl peroxide, 2-
ethylbutanoyl decanoyl peroxide, and mixtures thereof.
6. The composition as claimed in any one of the preceding claims,
characterized in that the emulsifier(s) is/are chosen from the group consisting of:
5 - a nonionic surfactant, preferably chosen from the group consisting of
oxyalkylenated fatty alcohols, alkoxylated fatty acids, oxyalkylenated (or
alkoxylated) plant or animal oils (hydrogenated or not), sorbitan esters
(alkoxylated or not), and mixtures thereof,
- a protective colloid agent, in particular chosen from the group consisting of:
10 a partially hydrolyzed polyvinyl acetate, a polyvinylpyrrolidone, a
polyacrylate, a xanthan gum, a cellulose or a derivative thereof, in particular
a methyl cellulose, a carboxymethyl cellulose, and a starch or a derivative
thereof, and mixtures thereof, more preferentially is chosen from the group
consisting of a partially hydrolyzed polyvinyl acetate, a xanthan gum, a
15 methyl cellulose, a carboxymethyl cellulose and mixtures thereof, more
preferentially is a partially hydrolyzed polyvinyl acetate, - mixtures thereof.
7. The composition as claimed in any one of the preceding claims,
characterized in that the antifreeze agent(s) has/have a molecular weight of less than
160 g/mol, preferably a molecular weight of less than 100 g/mol.
20 8. The composition as claimed in any one of the preceding claims,
characterized in that the antifreeze agent(s) is/are chosen from the group consisting of
C1-C6 alcohols, preferably chosen from the group consisting of methanol, ethanol,
ethylene glycol, isopropanol, n-propanol, propane-1,2-diol, propane-1,3-diol, glycerol,
butan-l-ol, butan-2-ol, butane-1,3-diol and butane-1,4-diol and mixtures thereof.
25 9. The composition as claimed in any one of the preceding claims, wherein
the hydrogen peroxide is present in a content ranging from 0.01% to 15% by weight,
more preferentially in a content ranging from 1% to 6% by weight, relative to the total
weight of the composition.
10. The composition as claimed in any one of the preceding claims,
30 comprising at least one antifreeze agent, the weight ratio between the total content of
antifreeze agent(s) and the total content of hydrogen peroxide preferably ranging from
0.1 to 10, more preferentially ranges from 0.5 to 5.
11. The use of the composition as defined in any one of the preceding claims
for the polymerization or copolymerization of one or more ethylenically unsaturated
35 monomers.
12. The use as claimed in claim 12, characterized in that the ethylenically
unsaturated monomers are halogenated vinyl monomers, preferably vinyl chloride.
18
13. A polymer, preferably a vinyl polymer, more preferentially a halogenated
vinyl polymer, obtained by polymerization of at least one ethylenically unsaturated
monomer in the presence of the composition as defined in any one of claims 1 to 11.