Di-sec-butyl peroxydicarbonate emulsion

Abstract

The present invention relates to an organic peroxide emulsion, which comprises at least one organic peroxide (the at least one organic peroxide comprises di-sec-butyl peroxydicarbonate), at least one emulsifier, at least one antifreeze agent, and water; the emulsion is free of methanol and ethanol. The present invention also relates to a method for preparing such an emulsion, to the use of such an emulsion for polymerizing or copolymerizing one or more ethylenically unsaturated monomers, and to a halogenated vinyl polymer obtained by using such an emulsion.

Description

Technical Field

[0001] The present invention relates to a methanol- and ethanol-free di-sec-butyl peroxydicarbonate emulsion, a process for its preparation, and its use in the polymerization or copolymerization of one or more ethylenically unsaturated monomers. The present invention also relates to a halogenated vinyl polymer prepared in the presence of such an emulsion. Background Art

[0002] Organic peroxides (in liquid or solid form) are commonly used as polymerization initiators for ethylenically unsaturated monomers in the synthesis of various types of polymers.

[0003] However, there is a certain amount of problems in their use frequently.Particularly, organic peroxides often constitute highly unstable species, because they decompose relatively easily under the effect of the slight input of heat, mechanical energy (friction or impact) or incompatible pollutants.Thereby, when some organic peroxide storage temperatures uncontrolledly raise, they can stand the exothermic decomposition of self-acceleration, which can cause ignition and / or violent explosion.In addition, under these conditions, some of these organic peroxides can release combustible vapors, which can react with any ignition source, and this can increase or even promote the risk of violent explosion violently.As a result, it is important to take the precautionary measures of appropriate safety aspects during the storage and transportation of organic peroxides.

[0004] In order to overcome these drawbacks, organic peroxides are packaged in particular in the form of aqueous emulsions containing antifreeze agents. Thus, the presence of water makes it possible both to absorb and dissipate the energy generated in the case of exothermic decomposition of the organic peroxide, while at the same time the antifreeze agent serves to keep the emulsion in liquid form at temperatures below -10°C, generally below -15°C, which makes it possible to limit the risk of involuntary exothermic decomposition of the organic peroxide.

[0005] In general, the aqueous emulsion also contains an emulsifier, which has the following advantages: reducing the interfacial tension between the aqueous phase and the organic peroxide, with the aim of promoting the dispersion of the peroxide in the form of droplets and maintaining the size of the droplets over time. In particular, over time, the peroxide droplets may settle, cream, or undergo Ostwald ripening, or may agglomerate together, resulting in an increase in their average size and maximum size, which in some cases may lead to complete or partial phase separation and, therefore, to overall instability of the emulsion.

[0006] In view of the above, therefore, for safety reasons, the aqueous organic peroxide emulsion must be stable, not only during its production, but also for relatively long periods of time before its use as a polymerization initiator, during its transportation and storage. For this purpose, as described above, the organic peroxide droplets must predominantly have small average and maximum sizes.

[0007] Thus, the peroxide droplets of the organic peroxide emulsion should have a low average size and preferably a uniform size distribution and should be stable over time, preferably over a period of at least 3 months. In particular, the maximum diameter of these droplets should very preferably not exceed 20 μm.

[0008] Furthermore, besides safety considerations (due to the instabilities described above) it is crucial to obtain a homogeneous emulsion with a small droplet size for reasons of quality and efficiency of the polymerization process. The reason for this is that the use of non-homogeneous organic peroxide emulsions, or emulsions with too large a droplet size as polymerization initiators in an emulsion or suspension of vinyl monomers can produce (lead to) inhomogeneities in the final product. Generally speaking, this inhomogeneity is characterized by poor gelation of the polymer particles during implementation in melt form ("fish eyes", hard particles). Today, the presence of hard particles makes polymer materials opaque. Thus, these stability considerations are very important for applications, especially medical applications, where the transparency of the final product is crucial.

[0009] Further, the use of non-uniform organic peroxide emulsions (i.e., emulsions with significantly different organic peroxide concentrations distributed between the upper and lower parts of the aqueous phase) can also lead to unexpected differences in initiator concentrations in the polymerization reactor. Differences in initiator concentrations in the polymerization reactor can cause problems with polymerization time. Too low a concentration reduces the productivity of the reactor because the polymerization time is extended and can have an impact on the quality of the polymer. Too high a concentration causes a very significant release of energy caused by the polymerization, and thus creates problems with evacuating this energy. The temperature of the polymerization reactor must then be controlled by various cooling means, such as jackets, refrigerated counter-blades, or condensers, and if the temperature is not well controlled, the polymerization run (operation) must be stopped.

[0010] In addition, the following steps are important steps for the quality of the polymer obtained, the reliability of the polymerization process, and the productivity: the discharge of the emulsion into the intermediate storage silo, the pumping and introduction of the organic peroxide emulsion into the polymerization reactor. These operating steps must be carried out in a short time. For this reason, it is important that the peroxide emulsion has a low viscosity so that the emulsion flows.

[0011] Thus, the organic peroxide emulsion should advantageously have a flowability less than or equal to 200 seconds measured by the consistometric cup technique (measured for example according to standard DIN 53211 with a viscosity cup diameter of 4 mm and a temperature of 5° C.).

[0012] Various organic peroxide emulsions have been developed.

[0013] For example, WO 99 / 31194 describes organic peroxide emulsions comprising an antifreeze agent and a chlorinated paraffin and optionally a nonionic surfactant and a protective colloidal agent.

[0014] WO 00 / 42078 relates to peroxide emulsions comprising copolymers of α,β-unsaturated dicarboxylic acids and C8-C24 α-olefins, the acid groups of which copolymers are esterified with ethoxylated alcohols and ethoxylated fatty alcohols having an HLB of >16.

[0015] US Pat. No. 5,369,197 describes organic peroxide emulsions comprising a protective colloid agent such as polyvinyl alcohol or xanthan gum and an alcohol, in particular methanol, ethanol or ethylene glycol.

[0016] JP H0676445 relates to peroxide emulsions comprising an antifreeze agent, a nonionic surfactant and / or a protective colloid agent, and alkali metal ions, alkaline earth metal ions and hydrogen ions.

[0017] GB 2083374 relates to an aqueous emulsion comprising an organic peroxide, an alcohol having a molecular weight of less than 100, and an emulsifier comprising polyvinyl alcohol.

[0018] FR 2995905 relates to aqueous organic peroxide emulsions free of protective colloid agents, comprising a nonionic surfactant as emulsifier and an antifreeze agent, preferably a mixture of methanol and propane-1,2-diol.

[0019] FR 2995906 describes aqueous organic peroxide emulsions in which the emulsifying agent is a colloidal agent consisting of polyvinyl acetate having a degree of hydrolysis greater than 80%.

[0020] In the specific case of di-sec-butyl peroxydicarbonate, an additional problem must be considered, that of the compatibility of the organic peroxide with the antifreeze agent.

[0021] In fact, today, the alcohols most commonly used as antifreeze agents 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 di-sec-butyl peroxydicarbonate when these alcohols come into contact with it, resulting in deterioration of the emulsion. The incompatibility between di-sec-butyl peroxydicarbonate and methanol and ethanol is specific to this peroxide and is not observed in the case of other peroxides (including other peroxydicarbonates).

[0022] In addition, compared with other commonly used organic peroxides, the specificity of di-sec-butyl peroxydicarbonate is that the density is greater than 1g / cm 3 (at 15°C). In emulsion, unlike other commonly used organic peroxides which tend to float, di-sec-butyl peroxydicarbonate tends to settle. Thus, di-sec-butyl peroxydicarbonate has a peculiar behavior in emulsion, which is very different from the behavior of other commonly used organic peroxides.

[0023] Therefore, there is a substantial need to provide di-sec-butyl peroxydicarbonate emulsions which can maintain low maximum and average droplet sizes and which remain stable and homogeneous over long periods of time. Summary of the invention

[0024] First, the present invention relates to an organic peroxide emulsion, which comprises:

[0025] - at least one organic peroxide comprising di-sec-butyl peroxydicarbonate;

[0026] - at least one emulsifier;

[0027] - at least one antifreeze agent; and

[0028] -water;

[0029] The emulsion is free of methanol and ethanol.

[0030] In certain embodiments, the at least one antifreeze agent is an alcohol, preferably selected from monohydric alcohols, dihydric alcohols, trihydric alcohols, and mixtures thereof.

[0031] In certain embodiments, the at least one antifreeze agent is selected from the group consisting of ethylene glycol, 2-propanol, 1-propanol, propane-1,2-diol, propane-1,3-diol, glycerol, butane-1-ol, butane-2-ol, butane-1,3-diol, butane-1,4-diol, diethylene glycol, triethylene glycol, and mixtures thereof.

[0032] In certain embodiments, the at least one antifreeze agent comprises, preferably consists of, propane-1,2-diol.

[0033] In certain embodiments, the at least one antifreeze agent is present in an amount of 10% to 40% by weight, preferably 15% to 25% by weight, relative to the total weight of the emulsion.

[0034] In certain embodiments, the at least one organic peroxide consists of di-sec-butyl peroxydicarbonate.

[0035] In certain embodiments, the di-sec-butyl peroxydicarbonate is present in an amount of 30 to 80 wt%, preferably 40 to 60 wt%, more preferably 45 to 60 wt%, relative to the total weight of the emulsion.

[0036] In certain embodiments, the at least one emulsifier comprises a nonionic surfactant, preferably selected from oxyalkylened fatty alcohols, oxyalkylened fatty acids, oxyalkylened vegetable or animal oils, polysorbates, sorbitan esters, non-oxyalkylened alkyl glycosides, oxyalkylened alkyl glycosides, and mixtures thereof.

[0037] In certain embodiments, the at least one emulsifier comprises at least one protective colloid agent, preferably at least one polyvinyl alcohol and / or hydrolyzed polyvinyl acetate.

[0038] In certain embodiments, the at least one emulsifier consists of at least one protective colloid agent, preferably at least one polyvinyl alcohol and / or hydrolyzed polyvinyl acetate.

[0039] In certain embodiments, the emulsion is free of polyvinyl alcohol and free of hydrolyzed polyvinyl acetate.

[0040] The present invention also relates to a process for preparing the emulsion as described above, the process comprising the following steps:

[0041] - mixing the at least one organic peroxide, the at least one emulsifier, the at least one antifreeze agent and water; and

[0042] - Emulsify the mixture.

[0043] The invention also relates to the use of an emulsion as described above for polymerizing or copolymerizing one or more ethylenically unsaturated monomers, in particular vinyl monomers, preferably halogenated vinyl monomers, and more preferentially vinyl chloride.

[0044] The present invention also relates to a halogenated vinyl polymer obtained by polymerizing at least one ethylenically unsaturated monomer in the presence of an emulsion as described above.

[0045] The present invention meets the above needs. More particularly, the present invention provides an emulsion comprising di-sec-butyl peroxydicarbonate which is stable and homogeneous over a long period of time and maintains a small average droplet size and a small maximum droplet size. Thus, the emulsion according to the invention can be transported and stored over a long period of time with complete safety. In addition, the emulsion according to the invention meets the required conditions in terms of viscosity and flow time. Further, when the emulsion according to the invention is used for the polymerization of ethylenically unsaturated monomers, it allows the production of polymers with a low content of hard particles.

[0046] This is achieved by the presence of an antifreeze agent in the emulsion, combined with the absence of both ethanol and methanol. In fact, as described above, it was found that the presence of methanol or ethanol in an emulsion of di-sec-butyl peroxydicarbonate resulted in decomposition of the peroxide and instability of the emulsion. Unexpectedly, it was found that an emulsion containing an antifreeze agent but without ethanol and methanol remained stable and homogeneous over a long period of time, had a suitable viscosity, and maintained a small droplet size. DETAILED DESCRIPTION

[0047] The invention is now described in more detail and in a non-limiting manner in the following description.

[0048] Herein, all percentages (%) shown are percentages by weight unless expressly stated otherwise.

[0049]

[00136] As used herein, amounts recited for a given species are applicable to that species according to all definitions of that species (as referred to herein), including more restricted definitions.

[0050] Lotion

[0051] The present invention relates firstly to organic peroxide emulsions.The emulsions according to the invention are aqueous emulsions, ie they comprise water, preferably demineralised or deionised water.

[0052] Particularly preferably, the emulsion is an oil-in-water emulsion.

[0053] 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 available, for example, from Arkema under the trade name 225 sales.

[0054] 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 emulsion.

[0055] 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 two organic peroxides, or a mixture of more than two organic peroxides, provided that one of the organic peroxides is di-sec-butyl peroxydicarbonate.

[0056] The at least one second peroxide is preferably selected from peroxydicarbonates, peroxyesters, and / or diacyl peroxides.

[0057] Among the peroxydicarbonates, preferred peroxides are: diethyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-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.

[0058] Among the peroxyesters, 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-n-heptanoate, cumyl peroxy-n-heptanoate, tert-amyl peroxy-n-heptanoate, tert-butyl peroxyneoheptanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, hydroxyperoxyesters, and mixtures thereof.

[0059] As hydroxyperoxyesters that can be used in the emulsions according to the invention, mention may be made of: 4-hydroxy-2-methylpentyl peroxyneodecanoate, 4-hydroxy-2-methylpentyl peroxy(2-ethylhexanoate), 4-hydroxy-2-methylpentyl 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-hydroxy-1,3,3-trimethylcyclohexyl peroxyneodecanoate, 4-hydroxy-2,6-dimethyl-2,6-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.

[0060] Among the diacyl peroxides, preferred peroxides are selected from: diisobutyryl peroxide, diheptanoyl peroxide, bis(2-ethylbutyryl) peroxide, bis(3,5,5-trimethylhexanoyl) peroxide, bis(2-ethylhexanoyl) peroxide; and asymmetric peroxides such as isobutyryl octanoyl peroxide, isobutyryl decanoyl peroxide, isobutyryl lauroyl peroxide, 2-ethylbutyryl decanoyl peroxide, 2-ethylhexanoyl lauroyl peroxide, and mixtures thereof.

[0061] More preferably, the second organic peroxide is selected from: tert-butyl peroxyneodecanoate (e.g. marketed by Arkema under the name 10), 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate (for example, sold by Arkema under the name 610), cumyl peroxyneodecanoate (for example sold by Arkema under the name 188), bis(2-ethylhexyl) peroxydicarbonate (for example sold by Arkema under the name 223), tert-amyl peroxyneodecanoate (e.g. sold by Arkema under the name 546), tert-butyl peroxypivalate (e.g. sold by Arkema under the name 11), tert-amyl peroxypivalate (e.g. sold by Arkema under the name 554), bis(3,5,5-trimethylhexanoyl)peroxide (for example sold by Arkema under the name 219 sales), and mixtures thereof.

[0062] When the emulsion comprises more than two peroxides, each of the peroxides different from di-sec-butyl peroxydicarbonate may be as described above.

[0063] Advantageously, the second organic peroxide(s) according to the invention has a half-life temperature of less than or equal to 90°C, preferably less than 80°C, measured in trichloroethylene at 1 hour.

[0064] Further, the second organic peroxide(s) in the emulsion according to the present invention advantageously has a storage temperature below 0°C.

[0065] Advantageously, the second organic peroxide(s) are liquid at the storage temperature, preferably at a storage temperature measured below 0°C, measured at atmospheric pressure.

[0066] Preferably, the emulsion according to the invention comprises at least one organic peroxide in an amount of 30% to 80% by weight, preferably 40% to 60% by weight, more preferentially 45% to 60% by weight, relative to the total weight of the emulsion. In particular, the amount of peroxide may be 0% to 35% by weight, or 35% to 40% by weight, or 40% to 45% by weight, or 45% to 50% by weight, or 50% to 55% by weight, or 55% to 60% by weight, or 60% to 65% by weight, or 65% to 70% by weight, or 70% to 75% by weight, or 75% to 80% by weight, relative to the total weight of the emulsion.

[0067] Advantageously, di-sec-butyl peroxydicarbonate is present in the emulsion in an amount of 30% to 80% by weight, preferably 40% to 60% by weight, more preferentially 45% to 60% by weight, relative to the total weight of the emulsion. In particular, the amount of di-sec-butyl peroxydicarbonate in the emulsion may be 30% to 35% by weight, or 35% to 40% by weight, or 40% to 45% by weight, or 45% to 50% by weight, or 50% to 55% by weight, or 55% to 60% by weight, or 60% to 65% by weight, or 65% to 70% by weight, or 70% to 75% by weight, or 75% to 80% by weight, relative to the total weight of the emulsion.

[0068] The emulsion according to the invention comprises at least one antifreeze agent. The antifreeze agent prevents the formation of gel when the emulsion is transported and / or stored in cold conditions, ie conventionally in an environment with a temperature below 0°C.

[0069] The antifreeze agent is preferably an alcohol. Thus, the antifreeze agent may be any alcohol that is water-soluble at storage temperature, for example at a temperature of 0°C. The term "water-soluble alcohol" means a solubility in water greater than 1% at 0°C. The amount of antifreeze agent in water may be measured by gas chromatography.

[0070] More particularly, the antifreeze agent may advantageously be a monohydric alcohol, a dihydric alcohol and / or a trihydric alcohol.

[0071] Preferably, the antifreeze agent is selected from ethylene glycol, 2-propanol, 1-propanol, propane-1,2-diol, propane-1,3-diol, glycerol, butane-1-ol, butane-2-ol, butane-1,3-diol, butane-1,4-diol, diethylene glycol, triethylene glycol, and mixtures thereof, which mixtures contain at least two of the antifreeze agents listed above. The mixture of antifreeze agents may contain two or more, preferably two, antifreeze agents as described above.

[0072] Particularly advantageously, the antifreeze agent is propane-1,2-diol, optionally as a mixture with one or more antifreeze agents, preferably antifreeze agents as described above. More advantageously, the antifreeze agent consists of propane-1,2-diol.

[0073] The emulsion according to the invention is ethanol-free and methanol-free.

[0074] The antifreeze agent 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 an antifreeze agent content allows the aqueous phase to remain in liquid form at temperatures as low as less than or equal to -20°C, preferably at temperatures as low as less than or equal to -25°C.

[0075] More particularly, the antifreeze agent may be present in the emulsion in an amount of 10% to 40% by weight, preferably 15% to 25% by weight, relative to the total weight of the emulsion. In certain embodiments, the emulsion comprises 10% to 15% by weight, or 15% to 20% by weight, or 20% to 25% by weight, or 25% to 30% by weight, or 30% to 35% by weight, or 35% to 40% by weight of the antifreeze agent, relative to the total weight of the emulsion.

[0076] The emulsions according to the invention comprise at least one emulsifier.

[0077] Preferably, the emulsifier according to the invention is readily biodegradable.The qualification of the biodegradability of the emulsifier is determined by the OECD 301 method, and more specifically by the OECD 301B method, by the release of carbon dioxide.

[0078] Preferably, the emulsifier comprises, or is, a non-ionic surfactant (ie consists of a non-ionic surfactant). Thus, the emulsion according to the invention may comprise at least one non-ionic surfactant.

[0079] Even more preferably, the emulsifier comprises or is an oxyalkylened or non-oxyalkylened nonionic surfactant selected from fatty alcohols, fatty acids, sorbitan esters, vegetable or animal oils (hydrogenated or non-hydrogenated), alkyl glycosides, and mixtures thereof. The nonionic surfactant mixture used in the present invention may be a mixture of only oxyalkylened nonionic surfactants, or a mixture of only non-oxyalkylened nonionic surfactants, or a mixture of oxyalkylened nonionic surfactants and non-oxyalkylened nonionic surfactants.

[0080] In certain embodiments, the nonionic surfactant may comprise or be one or more poly(ethylene oxide) block copolymers and poly(propylene oxide) block copolymers, optionally in combination with one or more other nonionic surfactants (e.g., as described herein).

[0081] Advantageously, the emulsifier comprises or is a nonionic surfactant selected from the group consisting of oxyalkylened fatty alcohols, oxyalkylened fatty acids, polysorbates, sorbitan esters, oxyalkylened vegetable or animal oils, non-oxyalkylened alkyl glycosides, oxyalkylened alkyl glycosides, and mixtures thereof.

[0082] The oxyalkylene unit is more particularly an oxyethylene unit (ie an ethylene oxide group), an oxypropylene unit (ie a propylene oxide unit), or a combination of oxyethylene units and oxypropylene units; preferably, the oxyalkylene unit is an oxyethylene unit, or a combination of oxyethylene units and oxypropylene units.

[0083] Thus, the nonionic surfactant is preferably selected from fatty alcohols containing oxyethylene units and optionally oxypropylene units, fatty acids containing oxyethylene units and optionally oxypropylene units, optionally hydrogenated vegetable or animal oils containing oxyethylene units and optionally oxypropylene units, polysorbates, sorbitan esters, alkyl glycosides containing oxyethylene units and optionally oxypropylene units, and mixtures thereof.

[0084] The oxyethylene units (ie, ethylene oxide groups) and the oxypropylene units (ie, propylene oxide groups) may be randomly distributed or in the form of blocks.

[0085] 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.

[0086] Preferably, the number of moles of ethylene oxide in the emulsifier ranges from 2 to 20.

[0087] 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 C8-C 40 Alcohols, preferably C8-C 20 alcohol.

[0088] Among the fatty alcohols that can be used in the invention, mention may especially be made of: 2-octyldodecanol, decanol, lauryl alcohol, oleocetyl alcohol, isodecyl alcohol, octanol, oxyisotridecyl alcohol, cetostrearyl alcohol, eleostearyl alcohol, caprylyl alcohol, myristyl alcohol, cetyl or palmityl alcohol, stearyl alcohol, eicosanyl or arachidyl alcohol, behenyl alcohol, oleyl alcohol, eicosenyl alcohol or gadoleyl alcohol, docosenyl alcohol, ricinoleyl alcohol, linoleyl alcohol, linolenyl alcohol, or mixtures thereof.

[0089] Preferably, the nonionic surfactant is chosen from oxyalkylened fatty alcohols and is preferably chosen from octyldodecanol, decanol, lauryl alcohol, oleyl cetyl alcohol, isodecyl alcohol, octanol, oxyisotridecyl alcohol, cetostearyl alcohol, octadecanol, octadecanol, caprylyl alcohol, myristyl alcohol, cetyl alcohol or palmityl alcohol, stearyl alcohol, eicosanol or arachidyl alcohol, behenyl alcohol, oleyl alcohol, eicosanol or eicosenyl alcohol, erucic acid alcohol, ricinoleyl alcohol, linoleyl alcohol or linolenic acid alcohol, which is oxyalkylened, preferably oxyethylened and / or oxypropylened and more preferentially oxyethylened and optionally oxypropylened.

[0090] More preferred fatty alcohols in the context of the present invention are oleyl cetyl alcohol, cetyl or palmityl alcohol, stearyl alcohol, oleyl alcohol, linoleyl alcohol, or mixtures thereof, and even more preferred are oxyalkylened, preferably oxyethylened and / or oxypropylened, and more preferably oxyethylened and optionally oxypropylened forms thereof.

[0091] More preferably, the nonionic surfactant is an oxyalkylened fatty alcohol selected from the group consisting of oxyethylened linoleyl alcohol, oxyethylened oleyl cetyl alcohol, oxyethylened cetyl alcohol or palmityl alcohol, oxyethylened stearyl alcohol, oxyethylened oleyl alcohol, and mixtures thereof.

[0092] The abovementioned fatty alcohols may optionally be oxypropyleneated to a minor extent.

[0093] Preferably, the oxyalkylened vegetable / animal oils (hydrogenated or non-hydrogenated) are derivatives of, in particular, ethoxylated mono-, di- and triglycerides and comprise a complex mixture of ethoxylated glycerol optionally linked to one or more fatty acid chains (which themselves may or may not be ethoxylated), fatty acids ethoxylated on the acid functions and / or on the hydroxy functions carried by the fatty acid chains, and variable proportions of fatty acids, glycerol and fatty acid mono-, di- or triglycerides.

[0094] 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 atoms, more preferentially from 8 to 20 carbon atoms.

[0095] The oxyalkylenated vegetable / animal oils (hydrogenated or non-hydrogenated) useful in the present invention are preferably selected from optionally hydrogenated, oxyalkylenated (or ethoxylated) vegetable oils.

[0096] The optionally hydrogenated, oxyethylenated vegetable oils are preferably chosen from ethoxylated castor oils and ethoxylated hydrogenated castor oils, which contain from 5 to 40 mol of ethylene oxide per 1 mol of ricinoleic acid. Mention may also be made of ethoxylated oils derived from coconut kernel oil, palm oil, palm kernel oil, olive oil, peanut oil, rapeseed oil, soybean oil, sunflower oil, walnut oil, hazelnut oil, coconut oil, poppy oil, safflower oil, linseed oil, perilla oil, oitica oil, and / or china wood oil.

[0097] As plant / animal oils that can be used as emulsifiers according to the invention, mention may be made of fats based on the following ethoxylations: (animal, cattle, sheep) tallow, crude or refined tall oil, whale oil, herring oil and / or sardine oil. All these ethoxylated glyceride derivatives are characterized in that they comprise a mixture of ethoxylated mono-, di- or tri-glycerides and corresponding fatty acids and glycerol ethoxylated derivatives. These fatty acids are especially saturated or unsaturated fatty acids derived from the following: caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, oleic acid, ricinoleic acid, erucic acid, linoleic acid, linolenic acid, eleostearic acid, 18 carbon-9,11,13-triene-4-keto acid (licanic acid), cis-9-eicosenoic acid (gadoleic acid), and / or erneic acid (erneic acid). Some unsaturated fatty acids may or may not be hydrogenated, such as in the case of ethoxylated castor oil, in which the ricinoleic acid groups may or may not be partially or fully hydrogenated.

[0098] In certain embodiments, the emulsifier according to the present invention may comprise or be one or more fatty acids, which are preferably oxyalkylened, more preferably oxyethylened and optionally oxypropylened, which may be selected from those listed above.

[0099] Advantageously, the emulsifier may comprise or be a nonionic surfactant chosen from oxyalkylenated vegetable or animal oils (hydrogenated or non-hydrogenated).

[0100] More preferentially, the emulsifier may comprise or be a nonionic surfactant chosen from vegetable oils, optionally hydrogenated, oxyethylened and optionally oxypropylened.

[0101] More preferentially, the emulsifier may comprise or be a nonionic surfactant chosen from ethoxylated, optionally hydrogenated vegetable oils comprising 5 to 40 mol of ethylene oxide, in particular ethoxylated hydrogenated castor oil and ethoxylated castor oil comprising 20 to 40 mol of ethylene oxide.

[0102] Even more preferentially, the emulsifier may comprise or be ethoxylated castor oil comprising from 20 to 40 mol of ethylene oxide.

[0103] Advantageously, the emulsifier may comprise or be one or more unethoxylated sorbitan esters and / or one or more ethoxylated sorbitan esters. Ethoxylated sorbitan esters are also referred to herein as "polysorbates", and unless otherwise indicated, the term "sorbitan esters" herein means unethoxylated sorbitan esters.

[0104] Preferably, the unethoxylated sorbitan ester is selected from sorbitan monostearate, sorbitan tristearate, sorbitan monolaurate, sorbitan trilaurate, sorbitan monooleate, sorbitan trioleate, sorbitan monopalmitate, and sorbitan tripalmitate, and combinations thereof.

[0105] Sorbitan monooleate is available under the trade name Span (obtained from Croda).

[0106] Preferably, the ethoxylated sorbitan ester (or polysorbate) contains between 3 and 40 ethylene oxide groups, preferably between 5 and 20 ethylene oxide groups.

[0107] Preferably, the ethoxylated sorbitan ester is selected from the group consisting of ethoxylated sorbitan monostearate, ethoxylated sorbitan tristearate, ethoxylated sorbitan monolaurate, ethoxylated sorbitan trilaurate, ethoxylated sorbitan monooleate, ethoxylated sorbitan trioleate, ethoxylated sorbitan monopalmitate, ethoxylated sorbitan tripalmitate, and combinations thereof.

[0108] Sorbitan monooleate 20OE (i.e. containing 20 ethylene oxide groups) is available under the trade name Surfaline (from Arkema) or Tween (obtained from Croda).

[0109] The emulsifier may contain or be one or more alkyl glycosides. As alkyl glycosides that can be used in the present invention, mention may be made of: octyl glycoside, octanoyl glycoside, lauryl glycoside, cocoyl glycoside, hexyl glycoside, isooctyl glycoside, decyl glycoside, and / or undecyl glycoside. These alkyl glycosides may or may not be oxyalkylened (and more particularly ethoxylated or not ethoxylated).

[0110] The emulsion may comprise a combination of at least two emulsifiers, in particular each of the at least two emulsifiers may independently be as described above.

[0111] Preferably, the combination of at least two emulsifiers comprises an unethoxylated sorbitan as defined above and an ethoxylated sorbitan comprising between 5 and 20 ethylene oxide groups, as described above.

[0112] In addition to or as an alternative to the use of one or more nonionic surfactants (e.g. as described above), the emulsion according to the invention may contain at least one protective colloid agent as emulsifier. Protective colloid agents are emulsifiers well known to those skilled in the art. For the purposes of the present invention, they refer to the group consisting of polyvinyl alcohol, polyvinyl acetate, and in particular partially hydrolyzed polyvinyl acetate, cellulose esters, and xanthan gum.

[0113] Thus, preferably, the protective colloid agent in the emulsion according to the invention is selected from polyvinyl alcohol, partially hydrolyzed polyvinyl acetate, cellulose esters, xanthan gum, and mixtures thereof. The hydrolyzed polyvinyl acetate is preferably hydrolyzed to an extent of 5 mol% to 85 mol%, preferably 5 mol% to 75 mol%.

[0114] The at least one emulsifier of the emulsion according to the invention may consist of at least one protective colloid agent.

[0115] More particularly, the emulsion according to the invention may comprise as said 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 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.

[0116] 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 optionally at least one protective colloid agent.

[0117] The emulsifier according to the invention may consist of at least one protective colloid agent and optionally at least one nonionic surfactant, in particular at least one nonionic surfactant as described above.

[0118] Alternatively, the emulsion according to the invention may be free of polyvinyl alcohol.The emulsion according to the invention may be free of partially hydrolyzed polyvinyl acetate, and more particularly may be free of polyvinyl acetate.

[0119] More particularly, the emulsion according to the invention may be free of protective colloid agents. This makes it possible, in particular, to reduce the time for the industrial preparation of the emulsion, since protective colloid agents in solid form, especially polyvinyl acetate, require a prior dissolution step, and to minimize the risks associated with the handling of powders. Furthermore, the presence of colloidal protective agents in the emulsion may increase the viscosity of the emulsion, which may be undesirable for certain applications.

[0120] The emulsion according to the invention may be free of cellulose esters, more particularly cellulose derivatives. The emulsion may be free of xanthan gum.

[0121] 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 contain the emulsifier in an amount ranging 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 of the emulsion.

[0122] The emulsion according to the invention may comprise the at least one nonionic surfactant in an amount of 0.1% to 10% by weight, preferably 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 0.1% to 0.5% by weight, or 0.5% to 1% by weight, or 1% to 2% by weight, or 2% to 3% by weight, or 3% to 4% by weight, or 4% to 5% by weight, or 5% to 6% by weight, or 6% to 7% by weight, or 7% to 8% by weight, or 8% to 9% by weight, or 9% to 10% by weight, relative to the total weight of the emulsion.

[0123] The emulsion according to the invention may comprise the at least one protective colloid agent in an amount of 0.1% to 10% by weight, preferably 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 0.1% to 0.5% by weight, or 0.5% to 1% by weight, or 1% to 2% by weight, or 2% to 3% by weight, or 3% to 4% by weight, or 4% to 5% by weight, or 5% to 6% by weight, or 6% to 7% by weight, or 7% to 8% by weight, or 8% to 9% by weight, or 9% to 10% by weight, relative to the total weight of the emulsion.

[0124] The emulsion according to the invention may also contain one or more additives intended to provide specific properties / characteristics to the final composition. Ideally, these additives will be present for the final polymerization or copolymerization.

[0125] The additive may be selected from defoamers, chain transfer agents, chain extenders, pH adjusters, plasticizers, and mixtures thereof.

[0126] The amount of the additive(s) is preferably the following: 0.1% to 10% by weight, preferably 1% to 5% by weight, relative to the total weight of the emulsion.

[0127] Preferably, the emulsion according to the invention comprises one or more plasticizers, preferably selected from aliphatic esters, such as phthalates, adipates, benzoates, hydrogenated derivatives of these molecules, and mixtures thereof. In particular, the plasticizer may be diisononylcyclohexane, diisononylcyclohexanedicarboxylic (formic) esters, and mixtures thereof. The plasticizer(s) may be present in the emulsion in an amount of 1% to 5% by weight, relative to the total weight of the emulsion.

[0128] Advantageously, the emulsion according to the present invention may consist essentially of, or consist of: the at least one organic peroxide, the at least one emulsifier, the at least one antifreeze agent, water, optionally one or more additives as described above. The term "emulsion consists essentially of ingredients" means that the total amount of these ingredients accounts for at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight of the total weight of the emulsion. The expression "consisting of..." does not exclude the presence of impurities present in trace amounts (e.g., in an amount less than or equal to 1% by weight relative to the total weight of the emulsion), such as impurities introduced with the organic peroxide. Thus, in certain embodiments, the emulsion according to the present invention may contain an organic solvent in an amount less than or equal to 1% by weight, relative to the total weight of the emulsion.

[0129] In other embodiments, the emulsion according to the invention may comprise an organic solvent, for example in an amount less than or equal to 20% by weight, relative to the total weight of the emulsion. In the present context, the term "organic solvent" means an organic solvent having 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 agent, water, an organic solvent (preferably in an amount less than or equal to 20% by weight relative to the total weight of the emulsion), and optionally one or more additives as described above.

[0130] The emulsion according to the invention may consist essentially of, or consist of, said at least one organic peroxide, said at least one emulsifier, said at least one antifreeze agent, and water (said emulsion being free of methanol and ethanol).

[0131] Preferably, the emulsion according to the invention has a fluidity (or flow time) at 5°C measured via the consistency 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 fluidity can be measured according to standard DIN 53211, with a viscosity cup diameter of 4 mm and a temperature of 5°C.

[0132] Particularly advantageously, the average droplet size of the emulsion according to the invention is 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 maximum droplet size of the emulsion according to the invention 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 (average and maximum) droplet size can be determined by conventional means using light scattering techniques. The measurement can be performed using a Malvern MasterSizer The equipment was operated at room temperature.

[0133] More advantageously, the emulsion according to the invention has the above mentioned droplet size during storage, for example for a period of at least 3 months.

[0134] Preferably, the concentration of the organic peroxide in the emulsion is uniform. The term "uniform concentration" means that the difference between the peroxide concentration (as mass percentage) at the top and the bottom of 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 sample taken from the bottom of the emulsion.

[0135] More advantageously, the emulsion according to the invention is homogeneous during a storage period, for example a period lasting at least 3 months.

[0136] Preparation of emulsion

[0137] The invention also relates to a process for preparing the emulsion according to the invention.

[0138] 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 agent, and water. When the emulsion comprises other ingredients, this step also comprises the above-mentioned mixing with the other ingredients of the emulsion, for example with one or more additives as described in the previous section (such as one or more additives, etc.). The mixing can be carried out in one step (the ingredients are all added to the mixture at the same time), or in several steps (first making a premix of some ingredients, then adding the other ingredients).

[0139] The process also comprises a step of emulsifying the mixture. The step of mixing the components of the emulsion and the step of emulsifying can be simultaneous. Alternatively, the emulsifying step can be performed sequentially after the first step of mixing the components of the emulsion.

[0140] The emulsion according to the invention can be prepared by dispersing at least an emulsifier and an antifreeze agent (and optionally one or more additives) in water so as to obtain a homogeneous aqueous phase, then adding to said aqueous phase one or more organic peroxides, then emulsifying the whole in the course of an emulsification step, preferably at a temperature below 5° C. and more preferably below −5° C., so as to limit premature degradation of the peroxides. Alternatively, the emulsifier or one or more of the emulsifiers may be dissolved in the organic peroxide(s) before addition to the aqueous phase.

[0141] The above steps may be performed in the specific order described above, or in a different order.

[0142] The temperature for preparing the emulsion is not critical, but it must be low enough to avoid a high decomposition rate of the organic peroxide, which would result in a loss of titer. The temperature chosen depends on the organic peroxide. It is, for example, between 15 and 10° C., preferably between −10 and 5° C. Preferably, the mixing and emulsification steps are carried out at the same temperature, preferably within the range stated above.

[0143] Preferably, deionized water or distilled water is used to prepare the aqueous emulsion.

[0144] The emulsification step of the process according to the invention is preferably carried out using a high shear mixer in order to optimally differentiate and / or homogenize the peroxide in the aqueous phase. Examples that may be mentioned include: mechanically rotating blades and anchor stirrers, impeller stirrers (i.e. one or more stirrers mounted on a common shaft), turbine stirrers (i.e. those comprising a baffle attached to the mixing vessel or adjacent to the stirrer member). Colloid mills and homogenizers may also be used.

[0145] According to one variant of the process according to the invention, an ultrasonic mixer or a rotor-stator mixer can be used for the emulsification.

[0146] After the emulsion is prepared, the step of pumping and introducing the emulsion into the polymerization reactor should generally be carried out as soon as possible. Therefore, the peroxide emulsion should advantageously have a low viscosity. Thus, immediately after production, the organic peroxide emulsion according to the invention is heated at -10°C and 100 s -1 The dynamic viscosity range under shear rate is preferably less than or equal to 850 mPa.s, more preferably less than or equal to 700 mPa.s, more preferably less than or equal to 500 mPa.s (the viscosity is, for example, measured according to standard DIN53019 using a Haake VT550 Viscotester instrument at -10°C and for 100 s -1 The shear rate was measured.

[0147] Its fluidity (measured by the consistency 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 standard DIN 53211 with a viscosity cup diameter of 4 mm and a temperature of 5° C.).

[0148] 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 (average and maximum) droplet size can be determined by conventional means using light scattering techniques, and the measurement can be performed using a Malvern Master Sizer The equipment was operated at room temperature.

[0149] use

[0150] 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 one or more vinyl monomers, preferably halogenated vinyl monomers, and more preferentially vinyl chloride.

[0151] As examples of ethylenically unsaturated monomers that can be used in the present invention, mention may be made of acrylates, vinyl esters, vinyl halide monomers, vinyl ethers, butadiene and / or aromatic vinyl compounds, such as styrene.

[0152] Preferably, the ethylenically unsaturated monomer is selected from vinyl halide monomers (ie, halogenated vinyl monomers), and more preferably the ethylenically unsaturated monomer is vinyl chloride.

[0153] The present invention also relates to a process for preparing a halogenated vinyl polymer, the process comprising the step of polymerizing or copolymerizing one or more ethylenically unsaturated monomers in the presence of an emulsion as described above. The ethylenically unsaturated monomers may be as described above, and more preferably vinyl chloride. The halogenated vinyl polymer prepared is preferably poly(vinyl chloride).

[0154] The polymerisation of the ethylenically unsaturated monomer(s), preferably vinyl chloride monomer, advantageously takes place in suspension, preferably at an initiation temperature in the range of 45°C to 70°C.

[0155] The emulsion can be added directly to the polymerization reactor, or it can be premixed with other organic peroxides, water, polyvinyl alcohol, and / or other additives before introducing the mixture into the polymerization reactor.

[0156] polymer

[0157] Another subject of the invention relates to a halogenated vinyl polymer obtained (or obtainable) by polymerization of at least one ethylenically unsaturated monomer as described above, in the presence of an emulsion according to the invention as described above. The polymerization may be as described in the preceding section.

[0158] Preferably, the invention relates to poly(vinyl chloride) obtained (or obtainable) by polymerization of vinyl chloride in the presence of the emulsion according to the invention.

[0159] The present invention also relates to a halogenated vinyl polymer obtained (or obtainable) via the preparation process as described above.

[0160] Such halogenated vinyl polymers have the advantage of having a low hard particle content. The hard particle content can be determined as described in the article by O. Leachs in Kunststoffe, Vol. 50 (4), 1960 pages 227-234.

[0161] Example

[0162] The following examples illustrate but do not limit the invention.

[0163] The following emulsions were prepared (the amounts stated in the following table are expressed as mass percentages relative to the total weight of the emulsion):

[0164] [Table 1]

[0165] Composition No. 1 2 3 4 5 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

[0166] [Table 2]

[0167] 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

[0168] qs100 = amount sufficient to give 100% by weight of the emulsion.

[0169] The properties of the compounds used are described below:

[0170] - Luperox 225: di-sec-butyl peroxydicarbonate;

[0171] -Surfaline LG15: nonionic surfactant, unsaturated C 16 –C 18 and C 18 Glycerol mono / diesters, which are polyethoxylated (15 units);

[0172] -PVA: polyvinyl acetate, degree of hydrolysis 72.5 mol % (Alcotex 72.5).

[0173] 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.

[0174] The emulsions were prepared as described below.

[0175] The aqueous phase containing the emulsifier, antifreeze and water was stirred at between 500 and 1000 rpm and maintained at -5°C (Celsius)

[0176] The organic peroxide was gradually added to the reactor containing this mixture. Stirring was continued for 3 minutes at 2000 rpm. Then, the whole was vigorously stirred at 9500 rpm for 2 minutes (except for emulsion No. 8, which was stirred for 6 minutes) using an "Ultra-Turrax S-25N 18G" blender, followed by stirring at 1000 rpm for 1 minute using a paddle. Each emulsification was carried out with a total of 200 g.

[0177] Subsequently, the emulsion was transferred to a plastic container, the solvent was sealed, and the emulsion was stored at -20°C for the indicated time.

[0178] As shown below, the flow time at 5°C (viscosity cup at 5°C), the average and maximum droplet size by volume over a period of 6 months, and the concentration of organic peroxide at the top and bottom of the aqueous phase of the emulsion (as weight percent relative to the total weight of the aqueous phase) were determined.

[0179] The flow time measurement is carried out according to standard DIN 53211 using a consistency cup (viscosity cup diameter: 4 mm), which is well known to the person skilled in the art. The measurement is carried out on 100 g of the emulsion after conditioning at +5° C. The flow time measurement is expressed in seconds and has an accuracy of ±10% of the specified value.

[0180] The average droplet size and the maximum droplet size were determined by conventional means using light scattering techniques. The device performs the measurements. The average droplet size and the maximum droplet size are given with an accuracy of ±0.5 μm (micrometer).

[0181] After 6 months storage at -20°C, samples from the top of the emulsion (taken from the first centimeter below the emulsion surface) and 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. The organic peroxide concentration in the aqueous phase was determined on a Waters H-class UPLC machine with an accuracy of ±1%.

[0182] The results are presented in the following table.

[0183] [Table 3]

[0184]

[0185] [Table 4]

[0186]

[0187]

[0188] It was observed that emulsions 7 and 8 according to the invention were more stable compared to emulsions 1 to 6. In fact, emulsions 1 to 6 underwent stratification after only 1 or 2 months of storage, while emulsions 7 and 8 remained stable over a period of at least 6 months. It was also observed that pressure developed in the containers of emulsions 1 to 6, which is a sign of decomposition of Luperox 225. In addition, the average droplet size of emulsions 7 and 8 remained small over a period of at least 6 months. Further, after 6 months, the concentrations of organic peroxides at the top and bottom of the aqueous phase of emulsions 7 and 8 were similar: emulsions 7 and 8 were still homogeneous after 6 months of storage.

[0189] Emulsion 9 according to the invention was also more stable than comparative emulsion 10, for which phase separation was observed as early as 2 hours after its preparation. On the other hand, emulsion 9 according to the invention maintained its stability over a period of at least 6 months, and during this period kept the average and maximum droplet sizes low. Furthermore, after 6 months, emulsion 9 remained homogeneous, with similar concentrations of organic peroxide at the top and bottom of the aqueous phase.

[0190] The viscosity cup values ​​of the emulsions according to the invention are relatively low and are suitable for polymerization applications.

Claims

1. An organic peroxide emulsion comprising: - at least one organic peroxide comprising di-sec-butyl peroxydicarbonate; - at least one emulsifier; - at least one antifreeze agent; and -water; The emulsion is free of methanol and ethanol, and the at least one antifreeze agent is present in an amount of 10% by weight to 40% by weight, relative to the total weight of the emulsion, The di-sec-butyl peroxydicarbonate is present in an amount of 30% by weight to 80% by weight relative to the total weight of the emulsion.

2. An emulsion as claimed in claim 1, wherein the at least one antifreeze agent is an alcohol.

3. The emulsion as claimed in claim 2, wherein the alcohol is selected from the group consisting of monohydric alcohols, dihydric alcohols, trihydric alcohols, and mixtures thereof.

4. The emulsion as claimed in any one of claims 1 to 3, wherein the at least one antifreeze agent is selected from ethylene glycol, 2-propanol, 1-propanol, propane-1,2-diol, propane-1,3-diol, glycerol, butane-1-ol, butane-2-ol, butane-1,3-diol, butane-1,4-diol, diethylene glycol, triethylene glycol, and mixtures thereof.

5. An emulsion as claimed in claim 4, wherein the at least one antifreeze agent comprises propane-1,2-diol.

6. An emulsion as claimed in claim 5, wherein the at least one antifreeze agent consists of propane-1,2-diol.

7. The emulsion as claimed in any one of claims 1 to 3, wherein the at least one antifreeze agent is present in an amount ranging from 15% by weight to 25% by weight relative to the total weight of the emulsion.

8. An emulsion as claimed in any one of claims 1 to 3, wherein the at least one organic peroxide consists of di-sec-butyl peroxydicarbonate.

9. An emulsion as claimed in any one of claims 1 to 3, wherein di-sec-butyl peroxydicarbonate is present in an amount ranging from 40% by weight to 60% by weight, relative to the total weight of the emulsion.

10. An emulsion as claimed in claim 9, wherein di-sec-butyl peroxydicarbonate is present in an amount ranging from 45% by weight to 60% by weight, relative to the total weight of the emulsion.

11. An emulsion as claimed in any one of claims 1 to 3, wherein the at least one emulsifier comprises a non-ionic surfactant.

12. An emulsion as claimed in claim 11, wherein the nonionic surfactant is selected from the group consisting of oxyalkylened fatty alcohols, oxyalkylened fatty acids, oxyalkylened vegetable or animal oils, polysorbates, sorbitan esters, non-oxyalkylened alkyl glycosides, oxyalkylened alkyl glycosides, and mixtures thereof.

13. An emulsion as claimed in any one of claims 1 to 3, wherein the at least one emulsifier comprises at least one protective colloid agent.

14. An emulsion as claimed in claim 13, wherein the at least one emulsifier comprises at least one polyvinyl alcohol and / or hydrolyzed polyvinyl acetate.

15. An emulsion as claimed in any one of claims 1 to 3, wherein the at least one emulsifier consists of: At least one protective colloid agent.

16. An emulsion as claimed in claim 15, wherein the at least one emulsifier consists of: At least one polyvinyl alcohol and / or hydrolyzed polyvinyl acetate.

17. An emulsion as claimed in any one of claims 1 to 3, which is free of polyvinyl alcohol and free of hydrolyzed polyvinyl acetate.

18. A process for preparing an emulsion as claimed in any one of claims 1 to 17, comprising the following steps: - mixing the at least one organic peroxide, the at least one emulsifier, the at least one antifreeze agent, and water; and - Emulsify the mixture.

19. Use of an emulsion as claimed in any one of claims 1 to 17 for polymerizing or copolymerizing one or more ethylenically unsaturated monomers.

20. The use as claimed in claim 19, wherein the ethylenically unsaturated monomer is a vinyl monomer.

21. The use as claimed in claim 20, wherein the vinyl monomer is a halogenated vinyl monomer.

22. The use as claimed in claim 21, wherein the halogenated vinyl monomer is vinyl chloride.

23. Halogenated vinyl polymer obtained by polymerization of at least one ethylenically unsaturated monomer in the presence of an emulsion as claimed in any one of claims 1 to 17.

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