Compositions based on allyl monomers and peroxides for manufacture of organic glass

Abstract

The invention relates to the use of one or more peracid esters of formula (I) for the polymerization of at least one allyl monomer and / or at least one allyl copolymer. The invention also relates to a polymerizable composition comprising at least one allyl monomer and / or at least one allyl copolymer and at least said peracid ester. The invention also relates to the use of a polymerizable composition as defined above for the manufacture of organic glass, preferably ophthalmic lenses. The invention also relates to organic glass obtained by polymerization of a polymerizable composition as defined above.

Description

[0001] The present invention relates to the use of one or more peracid esters as defined below for the polymerization of at least one allyl monomer and / or at least one allyl copolymer.

[0002] The present invention also relates to a polymerizable composition comprising at least one allyl monomer and / or at least one allyl copolymer and at least said peracid ester.

[0003] The present invention likewise relates to the use of the polymerizable composition as defined above for the manufacture of polymethyl methacrylate, preferably ophthalmic lenses.

[0004] The present invention also relates to polymethyl methacrylate obtained by polymerization of the polymerizable composition as defined above.

[0005] Polymethyl methacrylate, such as instrument or optical detector windows or ophthalmic lenses, can be prepared by free radical polymerization of one or more allyl monomers and / or allyl copolymers in the presence of one or more polymerization initiators (especially organic peroxides).

[0006] This free radical polymerization can in particular be carried out by pouring a polymerizable composition based on allyl monomer and / or allyl copolymer and organic peroxide into a mold having a geometry suitable for the desired application (especially a mold made of mineral glass).

[0007] The mold is generally an assembly that can consist of two glass parts, especially mineral glass parts, which are spaced apart by a recess and held together by the presence of a sealed seal, which is made of an elastomer and / or a thermoplastic material and is located at the periphery. Thus, the polymerizable composition is poured into the cavity formed between the two glass parts of the mold in order to undergo a suitable thermal cycle therein, during which the temperature can rise more or less gradually, while optionally observing one or more stable temperature stages.

[0008] During such a thermal cycle, the composition polymerizes and hardens in the mold to produce polymethyl methacrylate after removal from the mold, which can subsequently undergo various types of processing, depending on the desired application. The mold is generally reused in many thermal cycles.

[0009] The organic peroxides that are often used as polymerization initiators are entities that are generally highly unstable when heated. This is because, in the case of an uncontrolled increase in temperature, some organic peroxides can undergo self-accelerating exothermic decomposition, with a risk of ignition and / or violent decomposition. Thus, in places intended for the production of polymethyl methacrylate, this behavior proves difficult to reconcile with the current rules regarding the transport and storage of hazardous materials.

[0010] Thus, it has proven particularly advantageous to formulate such organic peroxides in liquid form in a solvent (also called desensitizer), i.e., in a diluted state, to reduce their thermal instability, thereby ensuring that they can be stored and transported under safer conditions.

[0011] For this purpose, the use of diisopropyl peroxydicarbonate (commonly known as IPP) in the radical polymerization of allyl monomers and / or allyl copolymers (diisopropyl peroxydicarbonate is dissolved in an allyl monomer, such as diethylene glycol bis(allyl carbonate), at a content of 27% by weight relative to the total weight of the composition) enables the production of polymethyl methacrylate with good optical properties, particularly in terms of transparency and low coloration, aesthetic properties, and mechanical properties. In other words, the polymethyl methacrylate obtained with such an organic peroxide composition has the advantages of being transparent and colorless and exhibiting good mechanical properties, such as in terms of hardness and abrasion. For example, such a composition can be sold by Arkema under the trade name Luperox® IPP27 or by Nouryon under the trade name Perkadox® IPP-NS27.

[0012] However, such a composition based on diisopropyl peroxydicarbonate exhibits too great a risk of uncontrolled decomposition during storage and transportation when the temperature rises uncontrollably.

[0013] This is because diisopropyl peroxydicarbonate is a "cold" peroxide, i.e., it exhibits a maximum transportation temperature of -20 °C, also called the controlled temperature, either alone or as a mixture with other peroxides and / or desensitizers, according to the UN Recommendations for Transportation of Dangerous Goods, 19th edition, 2015, section 2.5.3.2.4 concerning organic peroxides.

[0014] More generally, within the meaning of the present invention, the term "cold peroxide" is understood to mean any peroxide-based composition having a maximum transportation temperature of 20 °C.

[0015] Therefore, although diisopropyl peroxydicarbonate is diluted in an allyl monomer, it has proven necessary to continuously maintain very low temperatures, particularly below 20 °C, during the storage and movement of products such as Luperox® IPP27 or Perkadox® IPP-NS27, especially during maritime transportation, in order to minimize its decomposition risk, which greatly complicates its use.

[0016] Furthermore, in order to reduce the risk of premature polymerization of the allyl monomer, which functions as a desensitizer for the organic peroxide, it is necessary to control the temperature of these products during transportation and storage.

[0017] In addition, diisopropyl peroxydicarbonate also exhibits the following drawbacks, being too reactive to be stored and transported at a concentration greater than 30% by weight in allyl monomers.

[0018] To overcome these numerous difficulties, it has been envisaged to replace diisopropyl peroxydicarbonate with organic peroxides, such as diacyl-type aromatic peroxides or peresters, which can be stored and transported at ambient temperature.

[0019] However, such organic peroxides present the following drawbacks, leading to high polymerization temperatures, which can be greater than 120 °C, and in fact even greater than 125 °C, rather than around 80 °C for diisopropyl peroxydicarbonate. Thus, such polymerization temperatures tend to more or less rapidly damage the surface geometry of the glass mold as well as damage the elastomeric and / or thermoplastic seals, on the one hand preventing their reuse in many subsequent thermal cycles, and on the other hand leading to mechanical and optical defects in the formed polymethyl methacrylate.

[0020] In particular, it has been observed that the degree of cracking increases significantly when removing the polymethyl methacrylate formed with such organic peroxides from the mold.

[0021] In addition, such high polymerization temperatures promote the risk of yellowing of the polymethyl methacrylate. This is because this type of organic peroxide, especially benzoyl peroxide, can cause strong yellowing of the polymethyl methacrylate, which requires resorting to colorants that can compensate (if possible) for this yellowing. However, their presence is not always effective most of the time, or is not acceptable when wearing corrective glasses.

[0022] Finally, the thermal cycles, during which the polymerization temperature is at least 40 °C higher than the polymerization temperature usually applied for diisopropyl peroxydicarbonate, result in a significant excess of energy consumption, leading to additional costs associated with the annual production of polymethyl methacrylate.

[0023] In other words, the low reactivity of these organic peroxides that can be stored and transported at ambient temperature proves incompatible with the molding materials, thus leading to the deterioration of the molds and elastomeric and / or thermoplastic seals employed, promoting the formation of mechanical and optical defects in the obtained polymethyl methacrylate, especially as manifested by aggravating their yellowing, and increasing the production cost.

[0024] As a result, although such peroxides enable working under safer conditions, they generally lead to significantly worse mechanical and optical properties of the polymethyl methacrylate than those obtained with cold peroxides.

[0025] In view of the above, one of the aims of the present invention is to overcome the above-mentioned drawbacks, that is to say, to replace the organic peroxides commonly used during the polymerization of allyl monomers and / or allyl copolymers with other polymerization initiators that can be stored and transported alone or as a mixture at ambient temperature, in order to obtain plexiglass having good optical, aesthetic and mechanical properties, which is achieved without deteriorating the industrial equipment used during its manufacture.

[0026] In other words, there is thus a real need to use other polymerization initiators that can be stored and transported alone or as a mixture at ambient temperature, that is to say under safe conditions, while enabling the production of plexiglass that is particularly good in terms of transparency, color (especially yellowing), hardness and abrasion resistance.

[0027] In particular, one of the aims of the present invention is to improve the safety conditions for obtaining plexiglass without changing their optical, aesthetic and mechanical properties and without deteriorating the glass molds, in particular their geometric parameters, such as their surface geometry, as well as the elastomeric and / or thermoplastic seals necessary for their manufacture.

[0028] Thus, the subject of the present invention is in particular the use of one or more peresters corresponding to formula (I) for the polymerization of one or more allyl monomers and / or allyl copolymers:

[0029] [Chemical formula 1]

[0030]

[0031] where formula (I):

[0032] R 1 represents a straight-chain or branched, non-aromatic C 1 -C 10 alkyl group, preferably, R 1 represents a straight-chain C 1 -C 3 group, more preferably a C 1 -C 2 group, even more preferably a CH 3 group,

[0033] R 2 and R 3 represent hydrogen atoms,

[0034] R 4 represents a hydrogen atom or a straight-chain or branched C 1 -C 16 alkyl group; preferably, R 4 represents a straight-chain C 1 -C 11 group, more preferably a C 3 -C 11 group, still more preferably a C5 -C 10 、 and still more preferably C 5 -C 6 and even more preferably C 5 alkyl group.

[0035] One or more peroxyacid esters according to the invention are thus one or more non-aromatic tertiary alkyl peroxy esters.

[0036] The peroxyacid esters according to the invention have the advantage that they can be stored and transported alone or as a mixture with other peroxides and / or desensitizers, which are reactive or non-reactive at ambient temperature, i.e. under better safety conditions.

[0037] The term "ambient temperature" should be understood to mean a temperature that can be in the range of 21 °C to 30 °C.

[0038] Thus, the peroxyacid esters according to the invention have the following advantages: alone or as a mixture with other (reactive or non-reactive) peroxides and / or desensitizers, they exhibit a maximum transport temperature (also called the control temperature) strictly greater than 20 °C, according to the UN Recommendations for Transportation of Dangerous Goods, 19th edition, 2015, in section 2.5.3.2.4 concerning organic peroxides.

[0039] Thus, compared to the use of cold peroxides as defined above (especially with regard to organic peroxides belonging to the class of dialkyl diperoxycarbonates, in particular diisopropyl peroxydicarbonate dissolved in diethylene glycol bis(allyl carbonate) and sold under the name Luperox® IPP27 or the name Perkadox® IPP-NS27), the safety conditions for transportation and storage are improved.

[0040] The peroxy esters according to the invention are actually easier to handle, which has the advantage of significantly reducing the costs associated with their transportation and their storage, and can be more widely distributed throughout the world under safe conditions, including in the most inaccessible places.

[0041] The peroxyacid esters also present the following advantages: they can be used alone, i.e. in an undiluted state, which on the one hand eliminates the use of non-polymerizable solvents, such as oils (which are necessary for safety reasons and are liable to have a negative impact on the optical and mechanical qualities of the obtained polymethyl methacrylate), and on the other hand eliminates the use of polymerizable solvents, such as allyl monomers, which are liable to increase the risk of polymerization at an unregulated temperature during transportation or storage.

[0042] More generally, the peroxy esters according to the invention make it possible to dispense with any type of storage device (or device intended to store solvents) dedicated to polymerizable or non-polymerizable solvents at the site of peroxide production, which results in significant space savings and reduced maintenance costs.

[0043] In other words, the peroxides according to the invention make it possible to be free from any type of problems associated with the use of polymerizable or non-polymerizable solvents.

[0044] More particularly, the peroxy esters according to the invention make it possible to dispense with the commonly used desensitizers for peroxides (such as hydrocarbons, such as isododecane, mineral oils, esters, such as liquid phthalates, ethylbenzene or allyl monomers).

[0045] Thus, the peroxy esters can be packaged in more types of containers or devices than conventional, thermally unstable peroxides that are prone to decomposition during uncontrolled temperature rise.

[0046] Furthermore, the peroxy esters according to the invention exhibit sufficient reactivity to cause a polymerization temperature significantly lower than that of previously used organic peroxides that can be stored and transported at ambient temperature, without damaging the industrial equipment used in the molding process and without degrading the optical, aesthetic and mechanical properties of the plexiglass.

[0047] The term, "polymerization temperature" should be understood to mean the highest temperature reached during the thermal polymerization cycle.

[0048] In particular, the peroxy esters according to the invention do not reduce the geometric constants of the glass molds, such as their surface geometry, and the quality of the elastomeric and / or thermoplastic seals, which makes it possible to ensure the repeated use of the glass molds for subsequent thermal cycles.

[0049] In other words, the peroxy esters according to the invention exhibit the advantage of being compatible with glass molding techniques and elastomeric and / or thermoplastic seals.

[0050] The use of the peroxy esters according to the invention can additionally improve the growth on an industrial scale of plexiglass, in particular by minimizing the breakage rate after the plexiglass is removed from the mold and reducing any excessive energy consumption associated with its production.

[0051] The plexiglass thus obtained is in particular transparent, faintly colored, virtually even colorless, and has good mechanical properties, especially in terms of hardness and abrasion resistance.

[0052] Finally, the peroxy esters according to the invention are in particular produced from bio-based starting materials, which makes their production more environmentally friendly and more sustainable.

[0053] Another subject of the invention is a polymerizable composition comprising one or more peroxy esters (I) corresponding to the above formula, and one or more allyl monomers and / or allyl copolymers.

[0054] The compositions according to the invention make it possible to obtain, after polymerization, a polymethyl methacrylate having good optical, aesthetic and mechanical properties.

[0055] The compositions according to the invention are thus polymerizable or capable of being polymerized.

[0056] The invention also relates to the use of the compositions as defined above for the manufacture of polymethyl methacrylate.

[0057] Another subject according to the invention relates to a polymethyl methacrylate obtained by polymerizing the compositions as defined above.

[0058] The polymethyl methacrylate exhibits good aesthetic, optical and mechanical properties.

[0059] Compared with polymethyl methacrylates obtained with other organic peroxides which can be stored and transported at ambient temperature, this polymethyl methacrylate particularly exhibits improved hardness.

[0060] Other characteristics and advantages of the invention will become more apparent on reading the following description and examples.

[0061] In the following, and unless otherwise indicated, the limits of ranges of values included in this document are

[0062] The expression “at least one” is equivalent to the expression “one or more”.

[0063] Within the meaning of the present invention, the terms “peroxy ester” and “peroxide ester” are used indifferently.

[0064] Use

[0065] As shown above, the invention relates to the use of one or more peroxy esters corresponding to the above formula (I) for the polymerization of one or more allyl monomers and / or allyl copolymers.

[0066] The term, within the meaning of the present invention “non-aromatic” should be understood as R 1 not containing an aromatic ring.

[0067] In other words, R 1 represents an aliphatic C 1 -C 10 alkyl.

[0068] Preferably, in formula (I), R 1 represents a straight-chain or branched non-aromatic C 1 -C 6 and even more preferably C1 -C 5 、 also better C 1 -C 4 、 also more preferably C 1 -C 3 alkyl group.

[0069] Advantageously, in formula (I), R 1 represents a straight-chain C 1 -C 3 , more preferably C 1 -C 2 , alkyl group, more preferably a CH 3 group.

[0070] Advantageously, in formula (I), R 4 represents a hydrogen atom or a straight-chain C 1 -C 16 alkyl group.

[0071] Preferably, in formula (I), R 4 represents a straight-chain or branched-chain C 1 -C 11 , more preferably C 3 -C 11 , still more preferably C 5 -C 10 , still more preferably C 5 -C 6 and more preferably C 5 alkyl group.

[0072] Preferably, in formula (I), R 4 represents a straight-chain C 1 -C 11 , more preferably C 3 -C 11 , still more preferably C 5 -C 10 , still more preferably C 5 -C 6 and more preferably C 5 alkyl group.

[0073] Advantageously, in formula (I):

[0074] -R 1 represents a straight-chain C 1 -C 3 、 more preferably C 1 -C 2 alkyl group, more preferably a CH 3 group,

[0075] -R 2 and R 3 represent a hydrogen atom, and

[0076] -R 4 represents a straight-chain or branched C 1 -C 11 , more preferably C 3 -C 11 , even more preferably C 5 -C 10 alkyl; preferably, R 4 represents a straight-chain C 1 -C 11 , more preferably C 3 -C 11 , still more preferably C 5 -C 10 , still more preferably C 5 -C 6 and even more preferably C 5 alkyl.

[0077] The one or more peroxyacid esters are preferably selected from the following: tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-hexyl peroxyheptanoate, tert-heptyl peroxyheptanoate, tert-octyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-hexyl peroxycaprylate, tert-heptyl peroxycaprylate, tert-octyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-hexyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-heptyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-octyl 3,5,5-trimethylhexaneperoxycarboxylate, and mixtures thereof.

[0078] Preferably, the one or more peroxyacid esters are selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate, and mixtures thereof.

[0079] Advantageously, the one or more peroxyacid esters are selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, and mixtures thereof; more preferably, the one or more peroxyacid esters according to the invention are selected from tert-butyl peroxyheptanoate, tert-butyl peroxycaprylate, and mixtures thereof, and even more preferably is tert-butyl peroxyheptanoate.

[0080] The peroxyacid ester according to the invention is especially obtained from the reaction between a tert-alkyl hydroperoxide and an acyl halide, especially an acyl chloride, especially in the presence of one or more basic reagents.

[0081] Preferably, the peroxyacid ester according to the invention is especially obtained from the reaction between tert-butyl or tert-amyl hydroperoxide and an acyl halide, preferably an acyl chloride, especially n-heptanoyl chloride or n-octanoyl chloride.

[0082] Preferably, one or more peresters according to the present invention have a 10-hour half-life temperature (HLT 10h) greater than or equal to 75 °C.

[0083] The "10-hour half-life temperature" is the temperature at which half of the peroxide decomposes within 10 hours. In other words, it is the temperature at which the active oxygen content of the peroxide is reduced by half after 10 hours.

[0084] The 10-hour half-life temperature of the perester according to the present invention, denoted as HLT 10h, is preferably measured in an isododecane solution.

[0085] Preferably, the peresters according to the present invention have a 10-hour half-life temperature (HLT 10h) less than or equal to 110 °C.

[0086] Preferably, the peresters according to the present invention have a 10-hour half-life temperature between 70 °C and 110 °C, more preferably between 75 °C and 105 °C.

[0087] Preferably, the peresters according to the present invention have a 10-hour half-life temperature (HLT 10h) ranging from 95 °C to 105 °C.

[0088] The peresters according to the present invention additionally exhibit a self-accelerating decomposition temperature (SADT) greater than or equal to 50 °C, preferably greater than or equal to 60 °C.

[0089] The term "self-accelerating decomposition temperature" (SADT) should be understood to mean the lowest temperature at which an uncontrolled reaction, i.e., self-accelerating decomposition, occurs in its packaging. Preferably, this self-accelerating decomposition is measured in a 25 kg HDPE package. In other words, the self-accelerating decomposition temperature represents the temperature at which the chemical process leading to uncontrolled decomposition begins, possibly accompanied by spontaneous combustion and explosion phenomena. The self-accelerating decomposition temperature is measured, for example, according to Standard UN H.3 of the United Nations Manual of Tests and Criteria, 7th Revised Edition, 2019.

[0090] Advantageously, the peresters according to the present invention exhibit a 10-hour half-life temperature (HLT 10h) greater than or equal to 75 °C and a self-accelerating decomposition temperature (SADT) greater than or equal to 50 °C, preferably greater than or equal to 60 °C.

[0091] Preferably, the peresters according to the present invention correspond to formula (I), where R 4 represents a straight-chain C 1 -C 7 , in particular C 5 or C 6The alkyl group exhibits a 10-hour half-life temperature (HLT 10h) in the range of 95 °C to 105 °C.

[0092] Advantageously, one or more peracid esters according to the invention are produced from biobased starting materials.

[0093] The term "biobased" should be understood within the meaning of the present invention as one or more peracid esters being produced from compounds of plant and / or animal origin, preferably of plant origin.

[0094] One or more peracid esters according to the invention may comprise a biobased (i.e., carbon of plant and / or animal origin, especially of plant origin) carbon content of at least 20% by weight, preferably at least 50% by weight, more preferably 100% by weight, relative to the total weight of the carbon present in the peracid ester compound.

[0095] Advantageously, one or more peracid esters according to the invention may comprise a carbon content of greater than or equal to 50% by weight, preferably in the range from 55% by weight to 70% by weight, more preferably in the range from 60% by weight to 65% by weight, produced from renewable raw materials, relative to the total weight of the carbon present in the peracid ester compound.

[0096] 14 The content of C is substantially constant from the extraction of the renewable starting material until the manufacture of the copolymer according to the invention and even until the end of the life of the manufactured object made from said copolymer.

[0097] Thus, 14 The presence of C in the material (this is the case regardless of its amount) gives an indication of the origin of the molecules constituting it, i.e., they are derived from renewable starting materials rather than from fossil materials.

[0098] In the material 14 The amount of C can be determined by one of the methods described in the standard ASTM D6866-06 (Standard Test Methods for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis).

[0099] This standard includes three methods for measuring the organic carbon produced from renewable starting materials, with the organic carbon expressed as "biobased carbon". The ratios shown for the peracid esters of the present invention are preferably measured according to the mass spectrometry method described in this standard or by liquid scintillation spectrometry, and very preferably by mass spectrometry.

[0100] These measurement methods evaluate the 14 C / 12 C isotope ratio in the sample and compare it with the 14 C / 12 C isotope ratio in a material of biological origin that gives a 100% standard to measure the percentage of organic carbon in the sample.

[0101] Preferably, one or more peracid esters according to the present invention are liquid at ambient temperature, i.e., at a temperature in the range from 21 °C to 30 °C.

[0102] The allyl monomer may be selected from bis(allyl carbonate) monomers.

[0103] Advantageously, the allyl monomer is selected from bis(allyl carbonate) monomers of the following formula (II):

[0104] [Chemical formula 2]

[0105]

[0106] where formula (II):

[0107] R a and R c are the same or different and represent an allyl group of the following formula:

[0108] [Chemical formula 3]

[0109]

[0110] where formula R d is selected from:

[0111] - a hydrogen atom,

[0112] - a halogen atom, preferably a fluorine or chlorine atom,

[0113] -- a straight-chain or branched C 1 -C 4 alkyl group,

[0114] R b is selected from alkylene groups, alkylene ether groups, aromatic alkylene ether groups, polyalkylene ether groups, alkylene carbonate groups, and mixtures thereof.

[0115] Preferably, in formula (II), R a and R c are the same.

[0116] Preferably, R a and R c are the same and represent an allyl group, where R d represents a hydrogen atom, a chlorine atom, a fluorine atom, or a methyl or ethyl group.

[0117] Still more preferably, R a and R c are the same and represent allyl, where R d represents a hydrogen atom.

[0118] Preferably, R b represents an alkylene group, an alkylene ether group or an aromatic alkylene ether group.

[0119] The term "alkylene" is to be understood as meaning an alkyl group having unsaturation.

[0120] More preferably, R b represents an alkylene group or an alkylene ether group.

[0121] Still more preferably, R b represents an alkylene ether group, especially a group of the following formula:

[0122] [Chemical formula 4]

[0123]

[0124] In formula (II), R b is preferably aliphatic, that is to say it does not represent an aromatic alkylene ether group. In other words, the allyl monomer is preferably selected from the bis(allyl carbonate) monomers of formula (II).

[0125] The allyl monomer is preferably selected from: ethylene glycol bis(allyl carbonate), diethylene glycol bis(2-methyl carbonate), diethylene glycol bis(allyl carbonate) or ADC, ethylene glycol bis(2-chloroallyl carbonate), triethylene glycol bis(allyl carbonate), 1,3-propylene bis(allyl carbonate), propylene glycol bis(2-ethylallyl carbonate), 1,3-butylene bis(allyl carbonate), 1,4-butylene bis(2-bromoallyl carbonate), dipropylene glycol bis(allyl carbonate), trimethylene glycol bis(2-ethylallyl carbonate), pentamethylene glycol bis(2-ethylallyl carbonate), bisphenol A bis(allyl carbonate) and mixtures thereof.

[0126] Preferably, the allyl monomer is diethylene glycol bis(allyl carbonate), also known as ADC.

[0127] Other allyl monomers can be used alone or in combination with the above-mentioned bis(allyl carbonate) monomers, such as bis(allyl monocarbonate) monomers.

[0128] The allyl copolymer can be obtained by polymerization of the above-mentioned bis(allyl carbonate) monomers.

[0129] The allyl copolymer is preferably selected from poly(allyl carbonate) of polyols.

[0130] Poly(allyl carbonate) is obtained by polymerization of a polyol and a bis(allyl carbonate) monomer.

[0131] Among the polyols involved in the preparation of polyol poly(allyl carbonate), polyols selected from 1,6 - hexanediol, 1,4 - cyclohexanedimethanol, polycaprolactone diol, polyethoxylated glycerol diol, xylene - α,α - diol, 1,4 - bis(hydroxyethyl)toluene, 2,2 - bis(4 - (hydroxyethyl)phenyl)propane, pentaerythritol, trimethylolpropane, dipentaerythritol, bis - trimethylolpropane, tris(hydroxyethyl)isocyanurate can be particularly mentioned.

[0132] Allyl copolymers selected from polyol poly(allyl carbonate) can be used in combination with the above - mentioned allyl monomers, in particular bis(allyl carbonate) monomers of formula (II).

[0133] Allyl copolymers can also be obtained by polymerization of bis(allyl carbonate) monomers and diol polyethers.

[0134] The diol polyethers are preferably selected from homopolymers, copolymers or block polymers of polyether diols, such as those described in patent application US 6506864.

[0135] Preferably, the present invention relates to the use of at least one peroxyester of formula (I) for the radical polymerization of one or more allyl monomers and / or allyl copolymers, preferably one or more allyl monomers, in particular those selected from bis(allyl carbonate) monomers of formula (II).

[0136] More preferably, the present invention relates to the use of at least one peroxyester for the polymerization of diethylene glycol bis(allyl carbonate) (ADC), and the at least one peroxyester is selected from tert - butyl peroxyheptanoate, tert - amyl peroxyheptanoate, tert - butyl peroxycaprylate, tert - amyl peroxycaprylate, tert - butyl 3,5,5 - trimethylhexaneperoxycarboxylate and mixtures thereof.

[0137] Composition

[0138] As shown above, the composition according to the present invention is a polymerizable composition which comprises one or more of the corresponding peroxyacids of formula (I) and one or more allyl monomers and / or allyl copolymers as defined above.

[0139] Preferably, the composition comprises at least one allyl monomer selected from bis(allyl carbonate) monomers.

[0140] Advantageously, the composition comprises:

[0141] - at least one peroxyacid ester of formula (I), wherein:

[0142] R 1 represents a straight - chain or branched - chain C1 -C 3 、more preferably C 1 -C 2 alkyl, more preferably CH 3 group,

[0143] R 2 and R 3 represent a hydrogen atom, and

[0144] R 4 represents a straight-chain or branched C 1 -C 11 、more preferably C 3 -C 11 、even more preferably C 5 -C 10 alkyl; preferably, R 4 represents a straight-chain C 1 -C 11 ,more preferably C 3 -C 11 ,even more preferably C 5 -C 10 ,even more preferably C 5 -C 6 and even more preferably C 5 alkyl, and

[0145] - at least one allyl monomer selected from bis(allyl carbonate) monomers.

[0146] Preferably, the composition comprises at least one allyl monomer selected from the bis(allyl carbonate) monomers of formula (II) described above.

[0147] More preferably, the composition comprises at least one allyl monomer selected from the bis(allyl carbonate) monomers of formula (II), wherein R a and R c are the same and represent an allyl group, wherein R d represents a hydrogen atom, and R b represents an alkylene or alkylene ether group.

[0148] Preferably, the composition according to the present invention comprises:

[0149] - At least one peroxyester selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-hexyl peroxyheptanoate, tert-heptyl peroxyheptanoate, tert-octyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-hexyl peroxycaprylate, tert-heptyl peroxycaprylate, tert-octyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-hexyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-heptyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-octyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, preferably at least one peroxyester is selected from tert-butyl peroxyheptanoate, tert-butyl peroxycaprylate and mixtures thereof, more preferably tert-butyl peroxyheptanoate,

[0150] - At least one allyl monomer, which is preferably selected from bis(allyl carbonate) monomers, more preferably an aliphatic bis(allyl carbonate) monomer of formula (II) as defined above.

[0151] Advantageously, the composition according to the invention comprises:

[0152] - At least one peroxyester selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, preferably at least one peroxyester is selected from tert-butyl peroxyheptanoate, tert-butyl peroxycaprylate and mixtures thereof, more preferably tert-butyl peroxyheptanoate, and

[0153] - Diethylene glycol bis(allyl carbonate) (ADC).

[0154] Relative to the total weight of the allyl monomer and / or allyl copolymer present in the composition, the peroxyester present according to the invention can be present in the composition in a content range of 0.1% to 20% by weight, preferably in a content range of 1% to 16% by weight, more preferably in a content range of 2% to 15% by weight.

[0155] Preferably, relative to the total weight of the composition, the active oxygen content is 0.1% to 0.5% by weight, preferably the content is 0.15% to 0.4% by weight, more preferably 0.2% to 0.35% by weight. The expression "active oxygen content" (also referred to as "active O", "AO") should be understood to mean the weight percentage of oxygen free radicals (one oxygen atom per peroxyester functional group) relative to the total weight of the composition. In other words, the active oxygen content expressed in % can be calculated as: 16 / molar mass of the organic peroxide × weight concentration of the organic peroxide in the composition.

[0156] The composition according to the invention can additionally comprise at least one polymerization initiator different from the peroxyester according to the invention.

[0157] In this case, the polymerization initiator can be an additional organic peroxide or non-peroxide compound other than the peroxyester according to the invention, preferably an additional organic peroxide other than the peroxyester according to the invention.

[0158] Preferably, the composition according to the invention comprises at least one peroxyester as defined above, at least one additional organic peroxide, which is different from one or more peroxyester according to the invention, and one or more allyl monomers and / or allyl copolymers.

[0159] The composition according to the invention may further comprise one or more photoinitiators, for example, selected from acetophenone and benzophenone derivatives.

[0160] The composition according to the invention may further comprise one or more additional monomers other than allyl monomers.

[0161] The additional monomers are selected from acrylic monomers or methacrylic monomers, for example, those selected from methyl acrylate, methyl methacrylate, phenyl methacrylate, vinyl acetate, isopropyl isophthalate, diallyl terephthalate and diallyl adipate.

[0162] The composition according to the invention may further comprise at least one pigment and / or at least one organic dye, i.e., at least one colorant.

[0163] In this case, the composition may further comprise at least one dispersant, which functions to disperse the pigment in the composition.

[0164] According to a preferred embodiment, the composition comprises:

[0165] - diethylene glycol bis(allyl carbonate),

[0166] -- at least one peroxyester selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, preferably at least one peroxyester selected from tert-butyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate and mixtures thereof, more preferably tert-butyl peroxyheptanoate, and

[0167] - at least one pigment and / or an organic dye and optionally at least one dispersant.

[0168] Preferably, the colorant is a pigment.

[0169] The pigments that may be present in the composition can be organic or inorganic.

[0170] Among the inorganic pigments, mention may be made in particular of mineral pigments which may optionally be surface-treated.

[0171] The mineral pigments are preferably selected from titanium oxides, in particular titanium dioxide, iron oxides, such as iron oxide red or iron oxide yellow, and zirconium oxides.

[0172] The organic pigments may be selected from phthalocyanine blue, phthalocyanine green, dioxazine (cromophtal) violet and dioxazine green oxide.

[0173] Among the pigments, mention may be made in particular of phthalocyanine pigments, especially copper phthalocyanine pigments, in particular blue copper phthalocyanine pigments, and iron oxides.

[0174] Advantageously, the polymerizable composition is free of pigments.

[0175] The composition according to the invention may also comprise one or more release agents, such as the agent sold under the trade name Zelec® UN and available from Stepan.

[0176] The composition according to the invention is particularly liquid in a temperature range which can extend from 10 °C to 30 °C, more preferably from 15 °C to 25 °C.

[0177] The composition according to the invention as defined above is a polymerizable composition, that is to say it is capable of polymerizing under the action of heat.

[0178] The invention also relates to the use of the polymerizable composition as defined above for the manufacture of plexiglass, preferably ophthalmic lenses.

[0179] PMMA (Polymethyl Methacrylate)

[0180] Preferably, the polymerizable composition according to the invention gives plexiglass after polymerization.

[0181] Thus, the invention also relates to the plexiglass obtained by polymerization of the composition as defined above.

[0182] More specifically, the invention also relates to the plexiglass obtained by free radical polymerization of the composition as defined above.

[0183] The plexiglass is preferably selected from instrument windows, optical detectors and ophthalmic lenses.

[0184] Preferably, the plexiglass is selected from ophthalmic lenses.

[0185] Within the meaning of the present invention, the term "ophthalmic" means a lens which can be fitted into glasses and whose function is to protect the eyes from sunlight, in particular ultraviolet rays (sunglasses) or to correct vision. In the latter case, the ophthalmic lens is preferably afocal, single focal, bifocal, trifocal or progressive.

[0186] Thus, the ophthalmic lens can be of the multifocal or progressive or decremental multifocal type, that is to say a multifocal lens with variable strength.

[0187] The obtained ophthalmic lens can be covered with a coating or treated at its surface.

[0188] Advantageously, the invention relates to an ophthalmic lens obtained by polymerization of a composition as defined above.

[0189] According to one embodiment, the ophthalmic lens is obtained by polymerization of a composition comprising at least one peroxyester according to the invention and at least one allyl monomer, at least one peroxyester being selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-butyl peroxyoctanoate, tert-amyl peroxyoctanoate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, and at least one allyl monomer being selected from the bis(allyl carbonate) monomers of formula (II) above, in particular diethylene glycol bis(allyl carbonate).

[0190] Product obtained from the polymerizable composition

[0191] Another subject of the invention relates to a product resulting from the polymerization of one or more allyl monomers and / or one or more allyl copolymers in the presence of one or more peroxyesters according to the invention, as defined above.

[0192] Thus, the product is a polymer composition (or polymer product) resulting from the free radical polymerization of one or more allyl monomers and / or one or more allyl copolymers in the presence of one or more peroxyesters according to the invention, as defined above.

[0193] In other words, the polymer composition corresponds to a resin that can be used as a base material for manufacturing any type of object, which is used for its good mechanical, aesthetic and optical properties, in particular its optical quality.

[0194] Preferably, the polymer product or polymer composition can be shaped to obtain plexiglass or any other object that is used for its good mechanical and optical properties, in particular for its transparency and its weak coloring, and in fact even its colorless nature.

[0195] The polymer composition is in solid form in particular in the temperature range between 10 °C and 30 °C, more preferably between 15 °C and 25 °C.

[0196] Polymerization method

[0197] Similarly, the present invention also relates to a method for polymerizing a polymerizable composition as defined above, the method comprising at least one polymerization stage of the polymerizable composition as defined above, preferably carried out at one or more temperatures less than or equal to 110 °C.

[0198] The present invention also relates to a method for preparing a polymer composition as defined above, the method comprising at least one polymerization stage of the polymerizable composition as defined above, preferably carried out at one or more temperatures less than or equal to 110 °C.

[0199] Process for preparing PMMA

[0200] The method for preparing polymethyl methacrylate comprises a polymerization stage of at least one composition as defined above in a device comprising at least one mold, preferably at one or more temperatures less than or equal to 110 °C.

[0201] According to one embodiment, the method for preparing polymethyl methacrylate comprises at least the following stages:

[0202] -- a stage of introducing the polymerizable composition as defined above into a device comprising at least one mold,

[0203] - a polymerization stage of said composition, preferably carried out at one or more temperatures less than or equal to 110 °C; preferably, the polymerization stage is a series of stages at different temperatures such that shrinkage and polymerization can be controlled,

[0204] - a stage of collecting the polymethyl methacrylate.

[0205] According to this embodiment, the introducing stage is a stage of pouring or injecting the polymerizable composition according to the present invention into a device comprising at least one mold.

[0206] The device may comprise at least one mold having a complex geometry, for example, a biplanar mold, a mold comprising a recessed part and a protruding part, or a recessed-shaped mold.

[0207] Preferably, the device comprises at least one mold comprising at least one recessed part and at least one protruding part.

[0208] More generally, the device comprises at least one mold whose geometry exhibits the final geometry of the desired polymethyl methacrylate.

[0209] The device may further comprise at least one mold having one face with a geometry corresponding to the final geometry of the desired polymethyl methacrylate and another face which is not modeled as a function of the final geometry of the polymethyl methacrylate but which enables a second face of the polymethyl methacrylate to be prepared, which can subsequently be processed.

[0210] Preferably, the introduction stage includes pouring the polymerizable composition between two molds having a desired surface geometry, for example, one mold having a concave shape and one mold having a convex shape.

[0211] The polymerization stage is in particular free-radical polymerization.

[0212] The polymerization stage can be carried out by performing a thermal cycle in a temperature range less than or equal to 110 °C for a period of time sufficient to cause polymerization, in particular a period of time ranging from 10 hours to 30 hours, preferably 30 hours.

[0213] Thus, the temperature can be gradually increased during the polymerization stage.

[0214] The polymerization stage enables the desired polymethyl methacrylate to be produced.

[0215] The method for preparing polymethyl methacrylate may include, after the polymerization stage, an annealing stage of the polymethyl methacrylate, which is intended to eliminate possible residual stresses in the glass. The annealing stage can be carried out at a temperature ranging from 60 °C to 130 °C, preferably 70 °C to 100 °C, for a period of time ranging from 1 hour to 20 hours.

[0216] The stage of collecting the polymethyl methacrylate can be a stage including opening the mold and collecting the polymethyl methacrylate.

[0217] Thus, the method for preparing polymethyl methacrylate preferably includes the stage of pouring or injecting the composition according to the invention into a device including at least one mold having at least one concave part and at least one convex part, the stage of closing the mold, the polymerization stage of the composition as defined above, and the stage of opening the mold and collecting the polymethyl methacrylate.

[0218] The method according to the invention particularly enables the preparation of the above ophthalmic lenses.

[0219] The polymethyl methacrylate obtained after this preparation method can be subjected to any type of treatment, such as surface treatment, to improve its mechanical, aesthetic and optical properties, or also its wettability properties.

[0220] According to one embodiment, as shown above, the polymerizable composition according to the invention may additionally comprise at least one colorant, preferably at least one pigment and / or at least one organic dye.

[0221] Alternatively, the method for preparing polymethyl methacrylate according to the invention may include an additional stage, which includes adding at least one colorant, preferably at least one pigment, after obtaining the polymethyl methacrylate, i.e., after the polymerization stage.

[0222] The polymethyl methacrylate obtained according to this method exhibits good mechanical, aesthetic and optical properties.

[0223] The optical quality of the polymethyl methacrylate according to the present invention can be evaluated in particular by determining at least one of the following parameters:

[0224] - The refractive index (n D 20 ) measured with an Abbe refractometer (standardized method ASTM D-542),

[0225] - The yellowness index (YI) according to the standard CIE 1976 using the spectral formula of a spectrophotometer (standardized method ASTM E313) according to the following equation:

[0226] [Mathematical formula 1]

[0227]

[0228] In this equation, X, Y, and Z are the tristimulus coordinates of the sample, measured over the entire spectrum between 380 and 780 nanometers by a spectrophotometer.

[0229] The mechanical properties of the polymethyl methacrylate according to the present invention can be evaluated in particular by determining at least one of the following parameters:

[0230] - Rockwell hardness, measured using a Rockwell hardness tester (standardized method ASTM D-785),

[0231] - Shore D hardness, measured using an HPE II Shore D type portable hardness tester (standardized method ASTM D 2240),

[0232] - Elastic modulus, or

[0233] - Coefficient of friction.

[0234] Preferably, the mechanical properties of the polymethyl methacrylate according to the present invention can be evaluated by hardness.

[0235] The following examples are used to illustrate the invention but are not shown to be limiting in nature. Examples

[0236] The following examples illustrate the invention but do not limit the invention.

[0237] A. Examples of the preparation of peroxy esters

[0238] Synthesis of peroxide esters

[0239] Tert-alkyl peroxy esters are generally prepared by the reaction between hydroperoxides and acyl chlorides or acid anhydrides in the presence of a base, such as sodium hydroxide or a tertiary amine (see D. Swern - Organic Peroxides, Volume 1, page 74 - published by Wiley, 1970).

[0240] 1.1 Preparation of tert-butyl peroxyheptanoate

[0241] 74 g of a tert-butyl hydroperoxide solution (70%) was mixed with 116 g of a potassium hydroxide solution (30%) at a temperature of 5 - 10 °C in a glass reactor equipped with a jacket, condenser and stirring system. Then, 70 g of n-heptanoyl chloride (99.7%) was added to this solution in a controlled manner to keep the temperature between 5 °C and 10 °C. After reacting for 45 minutes at 5 - 10 °C, the temperature was raised to 20 - 25 °C within 15 minutes. After the reaction, the two phases were separated by sedimentation. The organic phase was washed with a sodium hydroxide solution (10%), then with a sodium metabisulfite solution (10%), and then with water. 67 g of a tert-butyl peroxyheptanoate solution was collected.

[0242] 1.2 Preparation of tert-amyl peroxyheptanoate

[0243] 32 g of a tert-amyl hydroperoxide solution (85%) was mixed with 59 g of a potassium hydroxide solution (30%) at a temperature of 5 - 10 °C in a glass reactor equipped with a jacket, condenser and stirring system. Then, 35 g of n-heptanoyl chloride (99.7%) was added to this solution in a controlled manner to keep the temperature between 5 °C and 10 °C. After reacting for 45 minutes at 5 - 10 °C, the temperature was raised to 20 - 25 °C within 15 minutes. After the reaction, the two phases were separated by sedimentation. The organic phase was washed with a sodium hydroxide solution (10%), then with a sodium metabisulfite solution (10%), and then with water. 26 g of a tert-amyl peroxyheptanoate solution was collected.

[0244] 1.3 Preparation of tert-butyl peroxyoctanoate

[0245] 52 g of a tert-butyl hydroperoxide solution (70%) was mixed with 83 g of a potassium hydroxide solution (30%) at a temperature of 5 - 10 °C in a glass reactor equipped with a jacket, condenser and stirring system. Then, 52 g of n-octanoyl chloride (98.8%) was added to this solution in a controlled manner to keep the temperature between 5 °C and 10 °C. After reacting for 45 minutes at 5 - 10 °C, the temperature was raised to 20 - 25 °C within 15 minutes. After the reaction, the two phases were separated by sedimentation. The organic phase was washed with a sodium hydroxide solution (10%), then with a sodium metabisulfite solution (10%), and then with water. 52 g of a tert-butyl peroxyoctanoate solution was collected.

[0246] 1.4 Preparation of tert-amyl peroxyoctanoate

[0247] 38 g of tert-amyl hydroperoxide solution (85%) was mixed with 66 g of potassium hydroxide solution (30%) in a glass reactor equipped with a jacket, condenser and stirring system at a temperature of 5 - 10 °C. Then 47 g of n-octanoyl chloride (98.8%) was added to the solution in a controlled manner to maintain the temperature between 5 °C and 10 °C. After reacting at 5 - 10 °C for 45 minutes, the temperature was raised to 20 - 25 °C within 15 minutes. After the reaction, the two phases were separated by sedimentation. The organic phase was washed with sodium hydroxide solution (10%), then with sodium metabisulfite solution (10%), and then with water. 39 g of tert-amyl peroxy-2-ethylhexanoate solution was collected.

[0248] B. Examples of the preparation of the polymerizable composition

[0249] A polymerizable composition was prepared starting from diethylene glycol bis(allyl carbonate) (CAS 142-22-3), sold by PPG under the trade name CR-39®, and each of the organic peroxides described below.

[0250] The organic peroxides tested were as follows (the proportion of organic peroxide corresponds to the weight ratio in the table below for 0.23% active oxygen in the composition):

[0251] [Table 1]

[0252]

[0253] C. Examples of the preparation of PMMA

[0254] Subsequently, each of the compositions obtained above was poured into a mold having a recessed part and a protruding part. Once poured, the protruding part was closed on the recessed part of the mold, and then the assembly was heated to a temperature less than or equal to 110 °C.

[0255] The thermal crosslinking cycle was adjusted as a function of the decomposition temperature of the organic peroxide used (half-life temperature (HLT) at 1 hour and 10 hours) according to the following scheme: raised to the 10-hour half-life temperature (HLT 10h) of the peroxide used within 14 hours, then raised to the 1-hour half-life temperature (HLT 1h) of the peroxide used within 4 hours at the HLT, and then cooled to a temperature of 70 °C, at which the removal from the mold was carried out.

[0256] The polymeric product thus obtained was annealed at a temperature ranging up to 130 °C for a period of time that could vary from 1 to 20 hours.

[0257] Subsequently, the plexiglass was collected.

[0258] D. Biphasic system for measuring optical properties

[0259] Measure the different optical properties of different plexiglasses, namely the Shore D hardness and the yellowness index (YI). These plexiglasses are prepared according to the above-mentioned scheme, with the exception of polymerization, which is carried out at 10 15 cm and a thickness of 4 mm. The flat glass sheets are arranged vertically and separated by a silicone rubber seal with a diameter of 4 mm. The mechanical cohesion of the assembly is generated by a clamping fixture under a constant pressure. All tests are carried out with an air inlet at the top of the mold.

[0260] The yellowness index YI is obtained using a SP 60 type spectrophotometer from the manufacturer X-Rite, according to the standard CIE 1976 (color sequence). The trichromatic coordinates are the trichromatic coordinates of Hunter Lab. The measurements are calibrated daily with standard calibration sheets (black and white), serial number: 20609 D65: 10°, 18 / 02 / 2010, WO A89274.

[0261] The YI measurement is carried out in a glass with a thickness of 4 mm and is represented by the difference from the YI measured on the white area of the Leneta Form2A chart (after calibrating the spectrophotometer, the measured yellowness index value is 10.48).

[0262] The Shore D hardness is measured using an HPE II Shore D type portable hardness tester (manufacturer: Bareiss, equipment for standard NFT51-174; DIN EN ISO 868; ISO 7619; ASTM D 2240; BS 903 Part A26).

[0263] For each plexiglass, the hardness of the plexiglass is measured five times and the average value of these measurements is retained.

[0264] The results regarding the hardness of the obtained plexiglasses are combined in the following table:

[0265] [Table 2]

[0266]

[0267] The hardness of the plexiglass obtained with the peroxyester according to the present invention is significantly greater than the hardness of the glass obtained with organic peroxides (tert-butyl peroxy-2-ethylhexanoate and tert-amyl peroxy-2-ethylhexanoate) that do not correspond to formula (I) according to the present invention.

[0268] Diisopropyl peroxydicarbonate cannot be stored and transported at ambient temperature.

[0269] The results regarding the yellowness index (YI) of the plexiglass obtained with the tested organic peroxides are combined in the following table:

[0270] [Table 3]

[0271]

[0272] Compared with the polymethyl methacrylate obtained with an organic peroxide not corresponding to the organic peroxide of formula (I) according to the invention, the polymethyl methacrylate obtained with the peroxyester according to the invention exhibits a lower yellowness index (YI) and / or enables the storage and transportation of the organic peroxide at ambient temperature.

Claims

Use of one or more peroxyacid esters of the following formula (I) for the polymerization of one or more allyl monomers and / or allyl copolymers: [Chemical formula 5] (I) wherein formula (I): R 1 represents a straight-chain or branched, non-aromatic C 1 -C 10 alkyl group R 2 and R 3 represent a hydrogen atom, R 4 represents a hydrogen atom or a straight-chain or branched C 1 -C 16 alkyl group.

2. The use according to claim 1, characterized in that In formula (I), R 1 represents a straight-chain C 1 -C 6 , preferably C 1 -C 5 , more preferably C 1 -C 4 , still more preferably C 1 -C 3 alkyl, and more preferably is a CH 3 group.

3. The use according to claim 1 or 2, characterized in that In formula (I), R 4 represents a straight-chain or branched C 1 -C 11 , more preferably C 3 -C 11 , still more preferably C 5 -C 10 alkyl; preferably, R 4 represents a straight-chain C 1 -C 11 , more preferably C 3 -C 11 , still more preferably C 5 -C 10 , still more preferably C 5 -C 6 and more preferably C 5 alkyl.

4. The use according to any one of the preceding claims, characterized in that one or more peroxyacid esters are selected from tert-butyl peroxyheptanoate, tert-amyl peroxyheptanoate, tert-hexyl peroxyheptanoate, tert-heptyl peroxyheptanoate, tert-octyl peroxyheptanoate, tert-butyl peroxycaprylate, tert-amyl peroxycaprylate, tert-hexyl peroxycaprylate, tert-heptyl peroxycaprylate, tert-octyl peroxycaprylate, tert-butyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, tert-amyl 3,5,5-trimethylhexaneperoxycarboxylate and mixtures thereof, preferably at least one peroxyacid ester is selected from tert-butyl peroxyheptanoate, tert-butyl peroxycaprylate and mixtures thereof, more preferably tert-butyl peroxyheptanoate.

5. The use according to any one of the preceding claims, characterized in that one or more peroxyacid esters have a 10-hour half-life temperature (HLT 10h) of greater than or equal to 75 °C.

6. The use according to any one of the preceding claims, characterized in that one or more peroxyacid esters have a self-accelerating decomposition temperature (SADT) of greater than or equal to 50 °C, preferably greater than or equal to 60 °C.

7. The use according to any one of the preceding claims, characterized in that the allyl monomer is selected from bis(allyl carbonate) monomers.

8. The use according to any one of the preceding claims, characterized in that the allyl monomer is selected from bis(allyl carbonate) monomers of the following formula (II): [Chemical formula 6] (II) wherein formula (II): R a and R c which are the same or different and represent an allyl group of the following formula: [Chemical formula 7] , wherein formula R d is selected from: - a hydrogen atom, - a halogen atom, preferably a fluorine or chlorine atom, -- linear or branched C 1 -C 4 alkyl, R b Selected from an alkylene group, an alkylene ether group, an aromatic alkylene ether group, a polyalkylene ether group, an alkylene carbonate group, and mixtures thereof.

9. The use according to any one of the preceding claims, characterized in that the allyl monomer is selected from ethylene glycol bis(allyl carbonate), diethylene glycol bis(2-methyl carbonate), diethylene glycol bis(allyl carbonate), ethylene glycol bis(2-chloroallyl carbonate), triethylene glycol bis(allyl carbonate), 1,3-propane bis(allyl carbonate), propylene glycol bis(2-ethylallyl carbonate), 1,3-butylene bis(allyl carbonate), 1,4-butylene bis(2-bromoallyl carbonate), dipropylene glycol bis(allyl carbonate), trimethylene glycol bis(2-ethylallyl carbonate), pentamethylene glycol bis(allyl carbonate), bisphenol A bis(allyl carbonate) and mixtures thereof.

10. The use according to any one of the preceding claims, characterized in that the allyl monomer is diethylene glycol bis(allyl carbonate).

11. A polymerizable composition comprising at least one peroxyacid ester as defined in any one of claims 1 to 6, and at least one allyl monomer as defined in any one of claims 1 and 7 to 10, and / or at least one allyl copolymer.

12. The composition according to claim 11, characterized in that it further comprises at least one additional organic peroxide different from the peroxyacid ester as defined in any one of claims 1 to 6.

13. Use of the composition as defined in claim 11 or 12 for the manufacture of plexiglass, preferably ophthalmic lenses.

14. A polymer composition, characterized in that it is obtained by polymerization of a polymerizable composition as defined in claim 11 or 12.

15. Plexiglass obtained by polymerization of a polymerizable composition as defined in claim 11 or 12, the plexiglass preferably being selected from instrument windows, optical detectors and ophthalmic lenses.

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