Ring-opening polymerisation method

Abstract

Provided is a method for preparing linear organopolysiloxanes OL by means of a ring-opening polymerization reaction from cyclic organopolysiloxanes OC, and using a basic catalyst B. More specifically, the method according to the present invention makes it possible to obtain controlled molar mass linear organopolysiloxanes OL with a very low cyclic content. The invention also relates to the composition S1 used in the context of the method of the present invention.

Description

[0001] TITLE OF THE INVENTION: Ring-opening polymerization process

[0002] Technical field:

[0003] The invention relates to a process for preparing linear organopoly siloxanes OL by a ring-opening polymerization reaction in the presence of cyclic organopoly siloxanes OC, a basic catalyst B and a chain blocker C. More specifically, the process of the present invention makes it possible to obtain linear organopoly siloxanes OL of controlled molar mass with a very low level of residual cyclic organopoly siloxane.

[0004] Technological background:

[0005] A major challenge for the silicone industry in the coming years is to industrially synthesize organopolysiloxanes with very low or even zero residual cyclic content.

[0006] To date, the industrial synthesis of organopolysiloxanes by polycondensation or ring-opening polymerization results in the formation of cyclic organopolysiloxanes such as octamethyltetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) or other unwanted cyclic organopolysiloxanes. In conventional industrial processes, this content of unwanted products can be between 10 and 15% relative to the total mass of linear organopolysiloxane obtained during the synthesis, which corresponds to thermodynamic equilibrium. Conventionally, this high content of cyclic products requires energy-intensive process steps such as a devolatilization step at high temperature and / or reduced pressure to separate these by-products from the linear organopolysiloxane obtained.Avoiding these steps improves production efficiency and reduces carbon dioxide emissions, resulting in a more environmentally friendly silicone product.

[0007] Thus, in the interests of economic and energy profitability, there is a need to develop new solutions to eliminate or at least limit these long and costly separation stages.

[0008] Furthermore, cyclic silicones or organopolysiloxanes such as octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) are and will be subject to restrictions for their use. In addition to the fact that these cyclic compounds present environmental risks due to their non-biodegradability, they are also suspected of being endocrine disruptors and potentially carcinogenic. In this sense, in 2018 European regulations limited the content of D4 and D5 to a content of 0.1% by mass in rinse-off cosmetic products. Soon, this regulation will be adopted for other cosmetic products but also in other areas of silicone applications. For example, in the electronics field, restrictions tend to limit the content of cyclic organopolysiloxanes to a value below 100 ppm.

[0009] Therefore, there is a need to develop processes for providing silicone products free of, or at least with a low content of, cyclic silicones. In particular, there is an interest in providing a composition polymerizable by opening the S ring allowing such a process to be implemented. There is also an interest in being able to reliably control the molar mass of the products formed. This possibility makes it possible to increase the prospects for use and applications of such polymers obtained.

[0010] In the prior art, patent application US2012142956A1 teaches a process for preparing linear organopolysiloxanes OL in the presence of a quaternary amine such as tetramethylammonium hydroxide or choline. On the one hand, the examples of patent application US2012142956 disclose that tests in the presence of choline and its derivatives do not allow satisfactory yields of linear organopolysiloxanes OL to be obtained. On the other hand, concerning tests with tetramethylammonium hydroxide there is a need to find an alternative to this catalyst and its derivatives which are toxic to humans and the environment.

[0011] More recently, a patent application such as WO2018051792 discloses a process for preparing linear organopolysiloxanes OL in the presence of guanidine derivatives as a basic catalyst. However, unlike the catalysts of the present invention, most guanidine derivatives need to be synthesized unlike commercially available choline. Furthermore, the process disclosed in patent application WO2018051792 requires the presence of chlorosilane known to be highly toxic compounds.

[0012] The development of this alternative technology allows the manufacture of more environmentally friendly silicone.

[0013] Furthermore, the present invention makes it possible to solve the multiple objectives listed below and those which will appear on reading the description of the invention which follows.

[0014] Summary of the invention: An objective of the present application is therefore to propose a process for preparing linear organopolysiloxanes OL by a ring-opening polymerization reaction of cyclic organopolysiloxanes OC making it possible to control the molar mass of the final product with a yield of linear organopolysiloxanes greater than 95%, preferably greater than 98%.

[0015] Another objective of the present application is to be able to control the nature of the chemical functions of the linear organopoly siloxane OL obtained.

[0016] Another objective of the present application is to provide a composition polymerizable by opening of the S ring allowing the implementation of this process.

[0017] Another objective of the present application is to propose a composition polymerizable by opening of the S ring which is low in toxicity and compatible with industrialization of the process.

[0018] Another objective of this application is to propose a process that is satisfactory from an industrial point of view and which is part of a so-called environmentally friendly chemistry.

[0019] Still other objectives will appear upon reading the description of the invention which follows.

[0020] Surprisingly, the Applicant has developed a ring-opening polymerizable composition S which meets these expectations. Thus, the present invention relates to a process for preparing linear organopolysiloxanes OL by a ring-opening polymerization reaction, said process comprising the following steps: a) Implementing a ring-opening polymerizable composition S comprising: i) at least one cyclic organopolysiloxane OC having three siloxane units, ii) at least one basic catalyst B of formula (I): in which:

[0021] -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,

[0022] -R2 represents a hydrogen atom or a radical -C(=O)-R3 with R3 representing an alkyl group of 1 to 12 carbon atoms;

[0023] - X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates,

[0024] -n is a natural number between 1 and 6, and iii) at least one chain blocker C. b) Optionally, subsequently add a chain blocker C identical or different to that of step a) or an acid A to the composition polymerizable by ring opening S mentioned in the previous step, c) Obtain the linear organopoly siloxane OL.

[0025] In this case, the basic catalyst B and the chain blocker C make it possible, during the process of the present invention, to control the molar mass of the final product while allowing the nature of the terminal chemical functions to be varied.

[0026] Detailed description of the invention:

[0027] Silicones, otherwise known as organopolysiloxanes, are polymeric materials comprising alternating silicon and oxygen atoms with various organic radicals bonded to the silicon.

[0028] In the context of the present invention, silicone or silicone product or silicone polymer or organopolysiloxane means polymers comprising a siloxane skeleton (Si-O-Si) having silicon and oxygen atoms alternating with various organic radicals linked to silicon. These silicone polymers can be liquid or solid, depending on the molar mass and the degree of polymerization.

[0029] For the purposes of the present invention, the term “reaction mixture” means all of the reactive chemical species present in the composition polymerizable by ring opening S mentioned above. By way of example, mention may be made of the catalyst(s) B, the cyclic organopolysiloxane(s) OC, the chain blocker(s) C.

[0030] All the viscosities discussed in this presentation correspond to a dynamic viscosity quantity at 25°C called “Newtonian”, i.e. the dynamic viscosity which is measured, in a manner known per se, with a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0031] For the purposes of the present invention, the cyclic organopolysiloxane OC is represented by the following formula (II): in which, R, identical or different, is a radical representing an alkyl group of 1 to 6 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, or an aryl group of 6 to 18 carbon atoms; and n represents a natural number between 1 and 2.

[0032] Preferably, the cyclic organopoly siloxane OC is represented by the formula (III): in which, R, identical or different, is a radical representing an alkyl group of 1 to 6 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, or an aryl group of 6 to 18 carbon atoms.

[0033] Examples include commercially available cyclic organopolysiloxanes OC such as hexamethylcyclotrisiloxane (CAS 541-05-9), 2-ethenyl-2',4,4',6,6'-pentamethylcyclotrisiloxane (CAS 18395-32-9), 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane (CAS 3901-77-7), hexaphenylcyclotrisiloxane (CAS 512-63-0),

[0034] 1.3.5-Trimethyl-l,3,5-tris(3,3,3-trifluoropropyl)cyclotrisiloxane (CAS 2374-14-3), le 2,2,4- Trimethyl-4,6,6-triphenyl-l,3,5,2,4,6-trioxatrisilinane (CAS 546-45-2), le 1,3,5-Trimethyl-

[0035] 1.3.5-triphenylcyclotrisiloxane (CAS 546-45-2); le 2 4 6-trimethylcyclotrisiloxane (CAS

[0036] 13269-39-1), le 3,5-trivinyl-l,3,5-trimethylcyclotrisiloxane (CAS 3901-77-7), le 2-Ethenyl- 2,4,4,6,6-pentamethylcyclotrisiloxane (CAS 18395-32-9), le 2, 4, 6, 8-

[0037] Tetramethylcyclotetrasiloxane (CAS 2370-88-9), le 2,4,6,8-Tetramethyl-2,4,6,8- tetravinylcyclotetrasiloxane (CAS 2554-06-5), le 2,4,6,8-Tetramethyl-2,4,6,8- tetraphenylcyclotetrasiloxane (CAS 77-63-4), l’octaphenylcyclotetrasiloxane (CAS 546-56-5).

[0038] Advantageously, the cyclic organopolysiloxane OC is hexamethylcyclotrisiloxane (CAS 541-05-9). According to one embodiment of the invention, the method of the present invention uses at least two cyclic organopolysiloxanes OC having 3 siloxane units such as for example the combination of hexamethylcyclotrisiloxane (CAS 541-05-9) and 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane (CAS 3901-77-7).

[0039] The introduction of these reagents into the reaction mixture is carried out simultaneously or successively. For example, hexamethylcyclotrisiloxane can be added first, followed by 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane, or vice versa. This implementation is suitable for various cyclic organopolysiloxanes OC having 3 siloxane units.

[0040] In the context of the present application, the basic catalyst B is represented by the formula (IV): in which: R1, identical or different, represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,

[0041] R2 represents a hydrogen atom or a radical -C(=O)-R3 with R3 representing an alkyl group of 1 to 12 carbon atoms;

[0042] X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates and n is a natural number between 1 and 6.

[0043] Examples of carboxylate anions include salicylate, oxalate, malonate, glyconate, maleate or citrate.

[0044] Concerning the carbonate anion, we can cite bicarbonate or carbonate.

[0045] For the purposes of the present invention, the term “siloxanolate” means the anionic compounds of the following siloxanols of formula (V): in which,

[0046] R 1 , identical or different, represents:

[0047] - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms,

[0048] -an alkenyl group comprising from 2 to 6 carbon atoms,

[0049] -a C6-C aryl group 18 ,

[0050] -a hydroxyl group, or

[0051] R 2 identical or different, represents:

[0052] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0053] -a hydroxyl group (OH),

[0054] - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, q is an integer between 1 and 20, preferably between 1 and 10, more preferably between

[0055] 1 and 5, and with the condition that at least one radical R 2is a hydroxyl group (OH).

[0056] Preferably, siloxanolate means the anionic compounds of formula (V) in which:

[0057] R 1 , identical or different, represents:

[0058] - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms,

[0059] -an alkenyl group comprising from 2 to 6 carbon atoms,

[0060] - a cycloalkyl group of 5 to 10 carbon atoms, optionally substituted by a heteroatom O, N, S or a halide,

[0061] -a C6-C aryl group 18 ,

[0062] -a hydroxyl group, or

[0063] R 2 identical represent:

[0064] - -a hydroxyl group (OH), q is an integer between 1 and 20, preferably between 1 and 10, more preferably between 1 and 5.

[0065] In the context of the present invention, the term silanolate means the anion associated with the compounds of trimethylsilanol (CAS 1066-40-6) or triethylsilanol (CAS 597-52-4).

[0066] We can also cite in particular the anions associated with silanols represented by the formula (VI): in which:

[0067] R is the same or different and represents:

[0068] -an alkyl group of 1 to 12 carbon atoms,

[0069] -a cycloalkyl group of 5 to 8 carbon atoms,

[0070] -an alkenyl group of 2 to 12 carbon atoms,

[0071] - a benzyl group or a phenyl, said radical R is optionally substituted by an alkyl, alkenyl chain of 2 to 6 carbon atoms, a cycloalkyl group, an aryl group or a heteroatom such as oxygen, sulfur or nitrogen.

[0072] Preferably, a person skilled in the art may use the compounds trimethyl silanol (CAS 1066-40-6) or triethylsilanol (CAS 597-52-4).

[0073] Preferably, the basic catalyst B is represented by the formula (VII): in which: R1, identical or different, represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms;

[0074] X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, and n is a natural number between 1 and 6.

[0075] Preferably, the basic catalyst B is represented by the formula (VII) above in which: R1 represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms; X represents an anion chosen from the group comprising: hydroxyl or silanolate and n is a natural integer between 1 and 6.

[0076] According to a specific embodiment of the invention, the basic catalysts B are represented above by the formula (VII) in which: R1 represents an alkyl chain of 1 or 2 carbon atoms;

[0077] X represents a trimethylsilanolate or triethylsilanolate anion and n is equal to 1.

[0078] We can notably cite basic catalysts B chosen from: choline hydroxide (CAS 123-41-1), choline silanolate, choline lactate (CAS 99150-55-7), triethylcholine hydroxide (CAS 3651-90-9), (2-hydroxyethyl)tripropylammonium hydroxide (CAS 96311-53-4), (2-hydroxyethyl)tributylammonium hydroxide, triethylcholine silanolate, choline bicarbonate (CAS 78-73-9), or choline salicylate (CAS 2016-36-6).

[0079] The molar quantity of basic catalyst B used in the process of the invention is from 150 ppm to 4000 ppm relative to that of the reaction mixture, preferably from 250 to 2500 ppm, more preferably from 250 ppm to 1500 ppm relative to that of the reaction mixture.

[0080] According to one embodiment of the invention, catalyst B is solubilized in a solvent chosen from alcohols or water.

[0081] According to one embodiment of the invention, the alcohol is chosen from: methanol (CAS 67-56-1), ethanol (CAS 64-17-5), propanol (CAS 71-23-8), isopropanol (CAS 67-63-0), butanol (CAS 71-36-3), allyl alcohol (CAS 107-18-6), benzyl alcohol (CAS 100-51-6), 3-buten-1-ol (627-27-0), long chain alkyl alcohols such as undecanol (CAS 112-42-5) or dodecanol (CAS 27342-88-7).

[0082] Preferably, catalyst B is solubilized in methanol or water.

[0083] For the purposes of the present invention, the chain blocker C is chosen from H2O, alcohols and their derivatives, or silanols and their derivatives.

[0084] In the context of the present application, the chain blocker C is chosen from H2O or the compounds of formula (VIII): in which:

[0085] Y represents a carbon atom or a silicon atom;

[0086] R is the same or different and represents:

[0087] -an alkyl group of 1 to 12 carbon atoms,

[0088] -a cycloalkyl group of 5 to 8 carbon atoms,

[0089] -an alkenyl group of 2 to 12 carbon atoms containing 1 to 6 unsaturated carbon-carbon bonds

[0090] -an aryl group of 6 to 18 carbon atoms, preferably phenyl,

[0091] -a benzyl group

[0092] - a siloxyl group having at least 5 units, preferably at least 10 units of formula R 1 cSiO(4-c) / 2 in which

[0093] R 1identical or different, represents an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably methyl; an aryl group comprising from 6 to 10 carbon atoms, preferably phenyl; and c = 0, 1 or 2 and; said radical R may be substituted or not by an alkyl chain of 1 to 12 carbon atoms, alkenyl of 2 to 6 carbon atoms, a cycloalkyl group of 5 to 8 carbon atoms, an aryl group of 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

[0094] In the context of the present application, the chain blocker C is chosen from H2O or the compounds of formula (VIII):

[0095] [Y represents a carbon atom or a silicon atom;

[0096] R is the same or different and represents:

[0097] -an alkyl group of 1 to 12 carbon atoms,

[0098] -a cycloalkyl group of 5 to 8 carbon atoms,

[0099] -an alkenyl group of 2 to 12 carbon atoms,

[0100] -an aryl group of 6 to 18 carbon atoms, preferably phenyl,

[0101] -a benzyl group

[0102] - a siloxyl group having at least 5 units, preferably at least 10 units of formula R 1 cSiO(4-c) / 2 in which

[0103] R 1 identical or different, represents an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably methyl; an aryl group comprising from 6 to 10 carbon atoms, preferably phenyl; and c = 0, 1 or 2.

[0104] In one embodiment of the present invention, the C-chain blocker is an alcohol or silanol having a pKa of 10 to 16, preferably a pKa of 12 to 16, more preferably a pKa of 14 to 16.

[0105] According to one embodiment of the invention, the chain blocker C is H2O.

[0106] According to another embodiment of the invention, the chain blocker C is a compound of formula (IX): in which:

[0107] Y represents a carbon atom,

[0108] R is the same or different and represents:

[0109] -an alkyl group of 1 to 12 carbon atoms,

[0110] -a cycloalkyl group of 5 to 8 carbon atoms,

[0111] -an alkenyl group of 2 to 12 carbon atoms,

[0112] - a benzyl or phenyl group, said radical R may be substituted or not by an alkyl chain of 1 to 12 carbon atoms, alkenyl of 2 to 6 carbon atoms, a cycloalkyl group of 5 to 8 carbon atoms, an aryl group of 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

[0113] According to one embodiment, the C-chain blocker is an alcohol selected from primary alcohols or secondary alcohols. Preferably, the C-chain blocker is an alcohol selected from primary alcohols.

[0114] According to one embodiment, the chain blocker C is an alcohol chosen from saturated or unsaturated polyols having 2 to 6 hydroxyl groups. By way of example, the following polyols may be mentioned such as glycerol, pentaerythritol, sorbitol or 1,4 butanediol.

[0115] According to one embodiment, the C-chain blocker is an alcohol having a pKa of 10 to 16, preferably a pKa of 12 to 16, preferentially a pKa of 14 to 16. According to one embodiment, the C-chain blocker is an alcohol chosen from: methanol (CAS 67-56-1), ethanol (CAS 64-17-5), propanol (CAS 71-23-8), isopropanol (CAS 67-63-0), butanol (CAS 71-36-3), allyl alcohol (CAS 107-18-6), benzyl alcohol (CAS 100-51-6), 3-buten-1-ol (627-27-0), long chain alkyl alcohols such as undecanol (CAS 112-42-5) or dodecanol (CAS 27342-88-7).

[0116] Preferably, the chain blocker is benzyl alcohol (CAS 100-51-6), butanol (CAS 71-36-3) or 3-buten-l-ol (627-27-0).

[0117] Alternatively, in the present application, the C-chain blocker has at least one terminal silanol function.

[0118] Preferably, the C-chain blocker having a terminal silanol function is trimethylsilanol (CAS 1066-40-6), triethylsilanol (CAS 597-52-4) or mixtures thereof.

[0119] According to another embodiment of the invention, the chain blocker C has at least one siloxyl unit.

[0120] According to another embodiment, the C-chain blocker having a terminal silanol chemical function has at least two siloxyl units. Alternatively, the C-chain blocker having a terminal silanol function has at least three siloxyl units.

[0121] A silanol terminal function is a chemical function at the end of the chain formed by the chemical bond between a silicon atom and a hydroxyl group.

[0122] According to one embodiment of the invention, the chain blocker C is represented by the formula (X): in which,

[0123] R 1 , identical or different, represents:

[0124] - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, optionally substituted by a heteroatom O, N, S or a halide,

[0125] -an alkenyl group comprising from 2 to 6 carbon atoms,

[0126] -a cycloalkyl group of 5 to 10 carbon atoms, optionally substituted by a heteroatom O, N, S or a halide, -a C6-C aryl group 18 , OR

[0127] -a hydroxyl group,

[0128] R 2 identical or different, represents:

[0129] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0130] -a hydroxyl group (OH), or

[0131] -a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, optionally substituted by at least one heteroatom O, N, S or a halide such as a fluorine atom, for example 1 to 10 fluorine atoms, for example (Ci-C5)alkyl-CF3, the alkyl being linear or branched; q is an integer between 0 and 20, preferably between 0 and 10, more preferably between 0 and 5, and with the condition that at least one radical R 2 is a hydroxyl group (OH).

[0132] According to one embodiment of the invention, the chain blocker C is represented by the formula (X) above: in which,

[0133] R 1 , identical or different, represents:

[0134] - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, optionally substituted by a heteroatom O, N, S or a halide,

[0135] -an alkenyl group comprising from 2 to 6 carbon atoms,

[0136] - a cycloalkyl group of 5 to 10 carbon atoms, optionally substituted by a heteroatom O, N, S or a halide,

[0137] -a C6-C aryl group 18 , OR

[0138] -a hydroxyl group,

[0139] R 2 identical represent:

[0140] - a hydroxyl group (OH), q is an integer between 0 and 20, preferably between 0 and 10, more preferably between 0 and 5.

[0141] In another embodiment, the chain blocker C is represented by the formula (X) above, wherein:

[0142] R 1 , identical, represents CH3,

[0143] R 2 identical or different, represents:

[0144] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0145] - a hydroxyl group (OH), - a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, or

[0146] -a C6-C aryl group 18 , optionally substituted; q is an integer between 0 and 20, preferably between 0 and 10, more preferably between 0 and 5, and with the condition that at least one radical R 2 is a hydroxyl group (OH).

[0147] In another embodiment, the chain blocker C is represented by the formula (X) above, wherein:

[0148] R 1 , identical, represents CH3,

[0149] R 2 identical, represent:

[0150] -a hydroxyl group (OH), and q is an integer between 0 and 20, preferably between 0 and 10, more preferably between 0 and 5.

[0151] The chain blocker C may be in a solvent. This is particularly advantageous in order to solubilize it in the reaction mixture. The solvent may in particular be a non-polar solvent such as an organic solvent of the alkane or aromatic hydrocarbon type. Preferably, the solvent is chosen from pentane, n-hexane, n-heptane, n-decane, n-dodecane, isododecane, EXXSOL D60, xylene, toluene and mixtures thereof.

[0152] Alternatively, the C-chain blocker can be in a polar solvent such as THF, Me-THF, or CH2CI2.

[0153] These chain blockers allow the functionalization of the linear organopolysiloxane OL during the polymerization reaction. Thus, it is possible to obtain linear organopolysiloxanes OL having, for example, identical or different terminal chemical functions.

[0154] According to one embodiment, the process of the invention is characterized in that in step a) of said process the molar ratio of chain blocker C relative to the basic catalyst B used is from 0.01 to 600, preferably from 0.8 to 300, preferentially from 1.5 to 300, preferentially from 4 to 200 and even more preferentially from 8 to 100.

[0155] According to one embodiment, the process of the invention is characterized in that during step a) the molar ratio of cyclic organopolysiloxane OC relative to the chain blocker C used is from 1 to 20,000, preferably from 2 to 5,000, preferentially from 2 to 1,400, preferentially from 4 to 700, even more preferentially from 4 to 300 and even more preferentially from 10 to 150. According to one embodiment of the invention, the linear organopolysiloxane OL is a compound of formula (XI): in which,

[0156] R, identical or different, represents:

[0157] -an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably methyl,

[0158] -an aryl group comprising from 6 to 10 carbon atoms, preferably phenyl,

[0159] R 1 , identical or different, represents:

[0160] -an alkyl group comprising from 1 to 5 carbon atoms

[0161] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0162] -a hydroxyl group (OH), or

[0163] -a C6-C aryl group 18 , preferably phenyl,

[0164] R 2 identical or different, represents:

[0165] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0166] -a hydroxyl group (OH),

[0167] -a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, optionally substituted by at least one heteroatom O, N, S or a halide such as a fluorine atom, for example 1 to 10 fluorine atoms, for example (Ci-C5)alkyl-CF3, the alkyl being linear or branched,

[0168] - a C5-C10 cycloalkyl group, optionally substituted,

[0169] -a C6-C aryl group 18 optionally substituted, or a group (OR 3 ) with R 3 representing: an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably OCH3 or OC2H5, an alkenyl group comprising from 2 to 15 carbon atoms, preferably from 2 to 10 carbon atoms, a C6-C aryl group 18OR alkylaryl such as a benzyl group q is an integer between 0 and 50, preferably between 0 and 20, more preferably between 0 and 10; preferably q = 0 ni represents an integer between 10 and 25,000, preferably between 10 and 5,000, preferably 10 and 1,500, preferably between 50 and 1,000, more preferably between 100 and 500; m2 represents an integer between 0 and 100, preferably between 0 and 50, more preferably between 0 and 30, preferably m2 = 0.

[0170] According to a preferred embodiment of the invention, the linear organopolysiloxane OL is a compound of formula (XI): in which,

[0171] R, identical or different, represents CH3 or phenyl, preferably CH3;

[0172] R 1 identical or different, represents:

[0173] -an alkyl group comprising from 1 to 5 carbon atoms

[0174] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0175] -a C6-C aryl group 18 , preferably phenyl,

[0176] R 2 identical or different, represents:

[0177] -an alkyl group comprising from 1 to 6 carbon atoms

[0178] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0179] -a hydroxyl group (OH),

[0180] -a C6-C aryl group 18 ,

[0181] -a group (OR 3 ) with R 3 representing: an alkyl group comprising from 1 to 10 carbon atoms, an alkenyl group comprising from

[0182] 2 to 10 carbon atoms, or a benzyl group q is an integer between 0 and 50, preferably between 0 and 20, more preferably between 0 and 10, preferably q = 0; n2 represents an integer between 10 and 1,500, preferably between 10 and 1,000, preferably between 50 and 1,000, more preferably between 100 and 500; m2 represents an integer between 0 and 500, preferably between 0 and 100, more preferably between 0 and 50.

[0183] According to a particularly preferred embodiment of the invention, the linear organopolysiloxane OL of the invention is a compound of formula (XI) in which,

[0184] R, identical or different, represents CH3 or phenyl, preferably CH3, R 1 , identical or different, represents CH3, phenyl or vinyl; R 2 identical or different, represents:

[0185] -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl,

[0186] -a hydroxyl group (OH),

[0187] - a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms,

[0188] -a C6-C aryl group 18 , optionally substituted, or

[0189] -a group (OR 3 ) with R 3 representing: an alkyl group comprising from 1 to 10 carbon atoms, an alkenyl group comprising from 2 to 10 carbon atoms, or a benzyl group q is equal to 0; ni represents an integer between 10 and 1,500, preferably between 10 and 1,000, preferably between 50 and 1,000, more preferably between 100 and 500; m2 represents an integer between 0 and 500, preferably between 0 and 100, more preferably between 0 and 50

[0190] According to one embodiment of the invention, the linear organopoly siloxane OL of the invention as represented above by formula (XI) is a compound for which R 2is identical. In other words, the linear organopolysiloxane OL is homotelechelic.

[0191] As a reminder, linear homotelechelic organopolysiloxane OL means a linear organopolysiloxane with identical terminal chemical functions.

[0192] Likewise, according to one embodiment of the invention, the linear organopolysiloxane OL of the invention as represented above by formula (XI) is a compound for which R 2 is different. In other words, the linear organopolysiloxane OL is heterotelechelic.

[0193] As a reminder, linear organopolysiloxane OL heterotelechelic is a linear organopolysiloxane having different terminal chemical functions.

[0194] For the purposes of the present invention, the mass-average molar mass and the number-average molar mass, denoted respectively Mw and M nof different linear organopolysiloxanes OL can be determined by size exclusion chromatography (SEC) in the presence of polystyrene standards in a solvent such as toluene at 35 °C.

[0195] According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its degree of polymerization is between 5 and 28,000, preferably between 5 and 7,000, preferably between 5 and 4,000, preferably between 15 and 2,000, more preferably between 20 and 1,000 and even more preferably between 20 and 400. According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its mass-average molar mass Mw can be between 500 and 2,000,000 g / mol, preferably between 500 and 500,000 g / mol, preferably between 500 and 300,000 g / mol, preferably between 1,000 and 150,000 g / mol, more preferably between 1,000 and 100,000 g / mol, even more preferably between 5,000 and 40,000 g / mol.

[0196] According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its number-average molar mass M n is between 500 and 2,000,000 g / mol, preferably between 500 and 500,000 g / mol, preferably between 500 and 300,000 g / mol, preferentially between 1,000 and 150,000 g / mol, more preferentially between 1,000 and 100,000 g / mol, even more preferentially between 5,000 and 40,000 g / mol.

[0197] According to one embodiment of the process of the invention, the linear organopoly siloxane OL of the invention is characterized in that its dynamic viscosity is between 100 and 1,000,000 mPa.s at 25°C, preferably between 1,000 and 500,000 mPa.s at 25°C, preferentially between 1,000 and 100,000, even more preferentially between 10,000 and 80,000 mPa.s at 25°C.

[0198] In the context of the present application, the mass percentage or the weight percentage of D4 of the products obtained according to the process of the present invention can be measured via the quantitative NMR spectra. 29 Yes. Alternatively, the mass percentage or weight percentage of D4 of the products obtained according to the process of the present invention could be measured via the chromatograms resulting from a size exclusion chromatography (SEC) analysis.

[0199] Hereinafter, the product resulting from the reaction is the sum of the linear organopolysiloxane OL and the cyclic organopolysiloxane OC at the end of the process of the present invention.

[0200] In one embodiment, the process according to the invention is characterized in that the content of cyclic organopoly siloxanes OC is less than 2%, preferably less than or equal to 1%, preferably less than or equal to 0.5% relative to the total mass of product resulting from the reaction.

[0201] In one embodiment, the process according to the invention is characterized in that the content of octamethylcyclotetrasiloxane (D4) is less than 2%, preferably less than or equal to 1%, preferably less than or equal to 0.5% relative to the total mass of product resulting from the reaction.

[0202] Preferably, the process of the invention is carried out without any solvent other than the quantity necessary to solubilize and / or dissolve catalyst B in the reaction medium.

[0203] This embodiment is particularly advantageous because it makes it possible to avoid the use of solvent, its treatment or recycling once used while obtaining satisfactory results when carrying out the method of the present invention.

[0204] However, in an alternative embodiment, the method of the invention is implemented in a non-polar solvent. The solvent may in particular be an organic solvent of the alkane or aromatic hydrocarbon type.

[0205] Preferably, the solvent is chosen from n-hexane, n-heptane, n-decane, n-dodecane, isododecane, EXXSOL D60, xylene, toluene and mixtures thereof.

[0206] Alternatively, the method of the invention is carried out in a polar solvent. The solvent may in particular be an organic solvent such as THF or Me-THF.

[0207] In one embodiment, the method of the invention is characterized in that the mass ratio, mass of cyclic organopolysiloxane OC relative to the mass of solvent used is from 0.5 to 50, preferably from 1.5 to 15, preferentially from 3 to 10 relative to the mass of solvent used.

[0208] Advantageously, and preferably, the reaction is carried out at a temperature between 25°C and 150°C, preferably between 35°C and 100°C, more preferably between 35°C and 80°C.

[0209] According to the process of the invention, the reaction time is between 1 minute and 48 hours, preferably between 1 minute and 18 hours, more preferably between 1 minute and 8 hours, even more preferably between 1 minute and 2 hours, and even more preferably between 1 minute and 1 hour.

[0210] The person skilled in the art will know how to adapt these parameters according to the nature of the reactors and the species used.

[0211] The process defined according to the present invention may further comprise a step b), by the subsequent addition of a chain blocker C identical or different to that of step a) or of an acid A to the composition polymerizable by ring opening S. Step b) of the process of the present invention allows flexibility in controlling the nature of the terminal chemical functions as well as in controlling the molar masses of the product OL.

[0212] Indeed, it is possible to obtain a homotelechelic or heterotelechelic linear organopoly siloxane OL depending on the nature of step b) of said process.

[0213] As a reminder, linear homotelechelic organopolysiloxane OL means a linear organopolysiloxane with identical terminal chemical functions.

[0214] A linear heterotelechelic organopolysiloxane OL is a linear organopolysiloxane having different terminal chemical functions.

[0215] According to one embodiment of the invention, the method further comprises a step b) defined by the subsequent addition of a C chain blocker identical to that introduced during step a) of said method.

[0216] This embodiment makes it possible to obtain a homotelechelic linear organopolysiloxane OL while controlling the molar mass of the product thus obtained.

[0217] According to one embodiment of the invention, the method further comprises a step b) defined by the subsequent addition of a C chain blocker different from that introduced during step a) of said method.

[0218] This embodiment makes it possible to control both the molar mass and the nature of the terminal chemical functions of the OL product. This gives a linear heterotelechelic OL organopolysiloxane.

[0219] According to one embodiment of the invention, the process of the invention is characterized in that the molar ratio of chain blocker C relative to the basic catalyst B used during step b) is from 1 to 200, preferably from 1 to 100, preferentially from 20 to 100.

[0220] According to one embodiment of the invention, the process of the invention is characterized in that the molar ratio of cyclic organopolysiloxane OC relative to the chain blocker C used during step b) is from 1 to 100, preferably from 5 to 80, preferentially from 10 to 50.

[0221] Alternatively, step b) of the process of the present invention comprises a step of subsequent addition of acid A to the polymerizable composition by ring opening S. This step b) makes it possible to neutralize the basic catalyst B and to stop the polymerization reaction carried out according to the process of the present invention.

[0222] This embodiment also makes it possible to control the nature of the terminal chemical functions of the OL product. This gives a linear heterotelechelic OL organopolysiloxane.

[0223] According to one embodiment of the process of the invention, the acid A introduced during step b) of said process is chosen from acids such as organic acids, Lewis acids, functionalized organohalosilanes, ion exchange resins or mineral acids

[0224] Regarding organic acids, we can notably cite carboxylic acid derivatives such as propionic acid, glycolic acid, valeric acid, butyric acid, caproic acid, caprylic acid, capric acid, octanoic acid, lauric acid, myristic acid, stearic acid, palmitic acid, oleic acid, undecylenic acid, or other carboxylic acid derivatives.

[0225] Preferably, acid A is selected from the group of carboxylic acid derivatives or mineral polyacids.

[0226] For the purposes of the present invention, the term "mineral polyacid" refers to a compound formed from hydrogen and one or more other elements (with the exception of carbon), which has the ability to release several protons in aqueous solution, unlike monoacids which can only release one. Examples include phosphoric acid, sulfuric acid or the oxonium ion.

[0227] According to one embodiment of the invention, acid A is phosphoric acid.

[0228] According to one embodiment of the invention, acid A has a pKa of from 1 to 13, preferably from 1.5 to 10, preferentially from 2 to 8.

[0229] It appears obvious that the person skilled in the art will know how to adapt the nature and quantity of the acid A introduced to meet the requirements of the process of the present invention.

[0230] According to a particular embodiment, step b) of the process of the present invention comprises a step of adding a chain blocker C identical or different to that of step a) and an acid A to the composition polymerizable by ring opening S. According to an embodiment of the process of the invention, step b) is carried out from 2 to 45 minutes after step a) of said process, preferably from 2 to 30 minutes, preferentially from 2 to 15 minutes after step a) of said process.

[0231] During step c) of the process of the present invention, the linear organopolysiloxane OL is obtained.

[0232] This step c) may further comprise one or more steps of federation, evaporation, distillation allowing the linear organopolysiloxane OL to be obtained.

[0233] The person skilled in the art will be able to adapt the implementation of these treatment steps as well as their operating conditions to meet the requirements of the process of the present invention.

[0234] The present application also relates to the linear organopolysiloxane OL obtained according to the different embodiments of the process of the present invention described above. It also relates to a silicone composition comprising the organopolysiloxane OL obtained according to the different embodiments of the process of the present invention described above.

[0235] The present application also relates to a composition SI comprising: i) at least one cyclic organopolysiloxane OC having three siloxane units, ii) at least one basic catalyst B of formula (XII): in which:

[0236] -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,

[0237] -R2 represents a hydrogen atom or a radical -C(=O)-Rs with R3 which represents an alkyl group of 1 to 12 carbon atoms;

[0238] - X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, and n is a natural number between 1 and 6, iii) at least one chain blocker C. According to one embodiment of the invention, the present application also relates to the composition SI comprising: i) at least one cyclic organopolysiloxane OC having three siloxane units, ii) at least one basic catalyst B of formula (XIII): in which:

[0239] -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms;

[0240] -X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, and n is a natural number between 1 and 6.

[0241] The present application also relates to the use of the organopolysiloxanes OL obtained according to the process of the present invention as an ingredient which can be directly used in various silicone formulations useful in fields such as cosmetics, household cleaning products, automobiles, energy.

[0242] Finally, the present application concerns basic catalysts B represented by the formula (XIV): in which:

[0243] -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms;

[0244] -X represents a siloxanolate or silanolate anion and n is a natural number between 1 and 6.

[0245] Preferably, the basic catalysts B represented by the formula (XIV) above: in which:

[0246] -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms;

[0247] -X represents a silanolate anion and n is a natural number between 1 and 6.

[0248] Basic catalysts B represented by formula (XIV) above: in which:

[0249] -R1 identical or different represents an alkyl chain of 1 or 2 carbon atoms;

[0250] -X represents a trimethyl silanolate or triethylsilanolate anion and n is equal to 1.

[0251] Examples:

[0252] Cyclic organopolysiloxanes used in the examples:

[0253] Cyclic organopolysiloxane OC1: hexamethylcyclotrisiloxane (CAS 541-05-9)

[0254] Cyclic organopolysiloxane OC2: 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane (CAS 3901-77-7)

[0255] Comparative cyclic organopolysiloxane OCcompi: octamethylcyclotetrasiloxane (CAS 556-67-2)

[0256] Basic catalysts B used in the examples:

[0257] Catalyst Bi: choline hydroxide (CAS 123-41-1) commercial diluted in water or methanol

[0258] Catalyst B2: choline trimethylsilanolate (13%) diluted in 1-3-buten-l-ol (CAS 627-27-0), synthesized within the framework of the invention.

[0259] Catalyst B3: triethylcholine trimethylsilanolate (13%) diluted in 1-3-buten-l-ol (CAS 627-27-0), synthesized within the framework of the invention.

[0260] Catalyst B4: choline bicarbonate (CAS 78-73-9)

[0261] Catalyst B5: choline salicylate (CAS 2016-36-6)

[0262] Catalyst Bcompi: Triazabicyclodecene CAS (5807-14-7)

[0263] Catalyst Bcomp2: KOSiMe3 (CAS 10519-96-7) diluted in 1-3-buten-l-ol (CAS 627-27-0), (13% by mass)

[0264] Bcom Catalyst P 3: KOSiMe3(CAS 10519-96-7)

[0265] Bcom Catalyst P 4: choline chloride (CAS 67-48-1)

[0266] Catalyst Bcomp5: Tetramethylammonium hydroxide (CAS 75-59-2)

[0267] Chain blockers implemented in the examples:

[0268] Ccompi chain blocker: divinyltetramethyldisiloxane (CAS 2627-95-4).

[0269] C1 chain blocker: benzyl alcohol (CAS 100-51-6)

[0270] C2 chain blocker: 1-3-buten-l-ol (CAS 627-27-0)

[0271] C3 chain blocker: triethylsilanol (CAS 597-52-4)

[0272] C4 chain blocker: trimethylsilanol (CAS 1066-40-6)

[0273] C5 Chain Blocker: H2O

[0274] C6 chain blocker: n-butanol (CAS 71-36-3)

[0275] In the context of the examples described below, the residual mass percentages of cyclic organopoly siloxanes OC (D3 or D4, D5 and D6) and the mass percentages of linear organopoly siloxane OL obtained according to the process of the present invention are measured by size exclusion chromatography (SEC) in the presence of polystyrene standards in a solvent such as toluene at 35°C.

[0276] Similarly, the number-average molar mass denoted M n of the different linear organopolysiloxanes OL according to the present invention is determined by the same size exclusion chromatography (SEC) method.

[0277] Example 1: Synthesis of catalysts B2 and B3:

[0278] In a 100 mL flask, weigh a solution of cholinium chloride or ethyl cholinium chloride (1.2 eq solubilized in 3-buten-l-ol alcohol at 15% by mass) and a solution of potassium silanolate (1.0 eq solubilized in 3-buten-l-ol alcohol at 25% by mass).

[0279] The cloudy reaction medium obtained is mixed under magnetic stirring for 2 hours at room temperature. After filtration, the catalysts B2 or B3 are obtained in the form of a clear solution at 13 wt% in 3-buten-1-ol alcohol. Example 2: General protocol of the polymerization process defined according to the invention:

[0280] In a 500mL reactor under an inert atmosphere (argon) a cyclic organopolysiloxane OC, a basic catalyst B and a chain blocker C are introduced. The reaction mixture is placed at 70°C with stirring for a period of 1h. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0281] Example 3a: Screening of the different basic catalysts B to implement the process of the invention:

[0282] In this example, the reaction mixture consists of the cyclic organopolysiloxane OC1 (10g), a basic catalyst B (5 to 9mg) and a chain blocker (with a ratio OC / C = 15 or OC / C = 21). For this entire example, the chain blocker C is 1-3-buten- l-ol (CAS 627-27-0) (C2). The reaction mixture is placed at 70°C with stirring. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0283] The nature of catalyst B, the reaction time, the molar quantity of catalyst B and the different products obtained at the end of the ring-opening polymerization reaction are mentioned in Table 1 below. Additional tests were carried out with an OC / C molar ratio equal to 15.

[0284] Regarding the calculation of molar ppm of catalyst B they were obtained according to the following calculations:

[0285] The tables above show that the basic catalysts B of the process of the present invention make it possible to carry out a ring-opening polymerization where the conversion is maximum in 10 to 30 minutes with a small quantity of secondary products, in this case the residual cyclic compounds.

[0286] In the following examples, all of these secondary products will be called residual OCs. Note that the only satisfactory comparative catalyst (B ComP 5) is a toxic and ecotaxic catalyst unlike those of the present invention.

[0287] Example 3b: Comparative examples in the presence of the cyclic organopoly siloxane OCcomp1:

[0288] In the first example, the reaction mixture consists of the comparative cyclic organopoly siloxane OCcompi (octamethylcyclotetrasiloxane), a basic catalyst Bi in the presence of Cs.

[0289] In this example the reaction mixture is placed at a temperature of 70°C for one hour with stirring. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0290] Under the above conditions, 12% of OL product (88% of OCcompi) is obtained. A second test is carried out with a reaction mixture comprising the comparative cyclic organopoly siloxane OCcompi (octamethylcyclotetrasiloxane), catalyst B2 and chain blocker C2 (with an OC / C ratio = 21).

[0291] In this example the reaction mixture is placed at a given temperature under stirring. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0292] At 70°C, with catalyst B2, 0% yield is obtained after 4 hours of reaction.

[0293] If we repeat the experiment with B2 and heat the reaction medium for 4 hours at 135°C, we obtain 10% of OL product (and 90% of OCcompi)

[0294] Example 4: Influence of the nature of the chain blocker C on the process of the invention:

[0295] The protocol of Example 2 is implemented with the cyclic organopolysiloxane OC1 (250g), the basic catalyst Bi (950 pmol) and the chain blocker C (52.7 mmol). The reaction mixture is placed at 70°C under stirring for 1 h. The molar ratio OC1 / C is equal to 21.

[0296] The table below mentions the nature of the chain blocker, the molar mass of the linear organopolysiloxane OL obtained and the mass percentage of residual cyclic organopolysiloxane OC resulting from the process of the present invention.

[0297] Test 1 shows that the conventional chain blocker such as Ccompi does not allow the molar mass of the product obtained to be regulated. Furthermore, it is observed that the percentage of cyclic secondary products (residual cyclic organopolysiloxanes OC) is higher than those obtained under the conditions of the claimed process. Indeed, the presence of chain blockers C of tests 2 to 5, claimed according to the process of the invention, makes it possible to obtain a very low level of cyclic secondary products (< 1%). In addition, these chain blockers make it possible to regulate the molar mass of the product obtained OL and to control the nature of the terminal chemical functions. Thus, the results set out in the table above show that the process of the invention is versatile and can be used with different chain blockers C defined according to the present invention.

[0298] Example 5: Influence of the quantity of chain blocker C on the process of the invention:

[0299] In this example, the protocol of Example 2 is implemented with the cyclic organopolysiloxane OC1 (250g), the basic catalyst Bi (950 pmol) and the chain blocker C4 (quantities defined in the table below). The reaction mixture is placed at 70°C with stirring for 1 h.

[0300] The table below mentions the molar ratio of OC1 compared to the moles of C as well as the molecular mass of the product obtained OL and the mass percentage of residual cyclic organopolysiloxane OC resulting from the process of the present invention.

[0301] The amount of chain blocker C introduced into the reaction mixture makes it possible to control the molecular mass of the linear product obtained OL.

[0302] Example 6: Obtaining homotelechelic or heterotelechelic organopolysiloxanes

[0303] In this example, the protocol of Example 2 is implemented with the cyclic organopolysiloxane OC1 (250g), the basic catalyst Bi (950 pmol) and the chain blocker C4 (52.7 mmol). The reaction mixture is placed at 70°C with stirring for a period varying from a few minutes to 1 h. Then, a sample is taken and analyzed by NMR- 1 H and NMR- 29 Yes. In this example, the initial molar ratio OC1 / C is identical for each test and is equal to 21.

[0304] In the tests mentioned in the table above different steps of the method of the present invention are implemented.

[0305] First, test 1 implements only step a) of the process of the present invention. This test makes it possible to obtain a homotelechelic linear organopolysiloxane OL.

[0306] As a reminder, linear homotelechelic organopolysiloxane OL means a linear organopolysiloxane with identical terminal chemical functions.

[0307] Test 2 implements step a) of the process of the present invention and the optional step b) of said process. In this example, step b) consists of a subsequent addition of the same C4 chain blocker. For test 2, this subsequent addition of C4 chain blocker occurs after a few minutes of reaction (8 to 15 min). A homotelechelic linear organopolysiloxane OL is thus obtained. This embodiment (test no. 2) makes it possible to control the molar mass of the OL product.

[0308] Finally, test 3 implements step a) of the process of the invention followed by step b) of said process. For this test, step b) consists of the addition of an acid (H3PO4) which makes it possible to obtain a linear heterotelechelic organopolysiloxane OL.

[0309] Thus, these different strategies detailed in the table above allow, depending on the nature of the inhibition of the reaction (addition of a second chain blocker or addition of acid in the reaction medium), to influence the nature of the terminal chemical functions of the linear organopolysiloxane OL obtained. The different NMR-' H and NMR- 29 If linear organopolysiloxanes OL thus obtained in tests 1 to 3 confirm these results. Example 7: Obtaining short α.ω-hydroxypolydi methyl siloxanes in solvent medium:

[0310] In this example, the protocol of Example 2 is implemented with the cyclic organopoly siloxane OC1 (250g), the basic catalyst Bi (950 pmol) and the chain blocker Cs (52.7 mmol)

[0311] In order to obtain a,co-hydroxypolydimethylsiloxane oils of low molar mass in number M n, chain blocker C is mixed with a solvent such as Me-THF (80mL) and the reaction mixture is heated to 45°C. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0312] Under these operating conditions, a linear organopolysiloxane OL is then obtained, having two hydroxyl functions at the end of the chain, with a molar mass in number M n of 6900 g / mol and a mass percentage of residual cyclic organopolysiloxane OC of 1.2%.

[0313] This test confirms the flexibility of the process of the present invention and the possibility of obtaining a,co-hydroxypolydimethylsiloxane oils of low molar mass in number M n .

[0314] Example 8: Block copolymers:

[0315] Characterization of V and D triads of copolymers by NMR:

[0316] Microstructure by NMR 29Si is an extremely effective means of analysis for determining the structure and microstructures of linear organopolysiloxanes OL. D units and V units are thus distinguished, respectively, resulting from the homopolymerization of the introduced cyclic organopolysiloxanes OC1 and OC2.

[0317] Thus the distribution of V units in the silicone chain is determined according to the distribution of the VVV, DW (or WD) and DVD triads. These triads are clearly assigned by NMR 29 If thanks to the presence of triplets characteristic of the VVV, DW (or WD) and DVD patterns. As a reminder, within the meaning of this application, the VVV, DW (or WD) and DVD triads are understood to mean the following patterns:

[0318] VVV Triad: DW (or WD) Triad:

[0319] DVD Triad:

[0320] The triads DDD, DDV and VDV will be declined in a similar manner

[0321] In the context of the present example, the term “statistical product” means a linear organopolysiloxane OL obtained according to the process of the invention having a random distribution of vinyl units (V).

[0322] On the other hand, in the sense of the present invention, the linear organopolysiloxane OL obtained according to the process of the invention having a non-random distribution of vinyl units (V) is called block copolymers.

[0323] In the context of the present example, the method of the present invention is implemented according to six different embodiments:

[0324] In a pillbox under an inert atmosphere (argon) a cyclic organopolysiloxane OC, a basic catalyst B (800 ppm) and a chain blocker C are introduced. The reaction mixture is placed at 70°C with stirring for a period of 1 h. A sample is taken and analyzed by NMR- 1 H and NMR- 29 If.

[0325] In the various tests A, B and C mentioned below, the cyclic organopolysiloxanes introduced are OC1 (5g, 70% mol) and OC2 (2.5g, 30% mol). The basic catalyst Bi is in solution in methanol and the chain blocker is C4.

[0326] Test A: is carried out with the cyclic organopolysiloxanes OC1 and OC2 introduced simultaneously.

[0327] Test B is carried out with the cyclic organopolysiloxane OC1, then the cyclic organopolysiloxane OC2 is introduced about ten minutes after the start of the reaction. Test C: is carried out with the cyclic organopolysiloxane OCi, then OC1 is introduced about ten minutes after the start of the reaction.

[0328] In the various tests D, E and F mentioned below, the cyclic organopolysiloxanes introduced are OC1 (5g, 80% mol) and OC2 (1.7g, 20% mol). The basic catalyst Bi is in solution in water and the chain blocker is C6.

[0329] Test D: is carried out with the cyclic organopolysiloxanes OC1 and OC2 introduced simultaneously.

[0330] Test E: is carried out with the cyclic organopolysiloxane OC1, then the cyclic organopolysiloxane OC2 is introduced about ten minutes after the start of the reaction. Test F: is carried out with the cyclic organopolysiloxane OC2, then the cyclic organopolysiloxane OC1 is introduced about ten minutes after the start of the reaction.

[0331] Thus, the experimental data measured under the above-mentioned conditions demonstrate the tendency to form block copolymers under these specific experimental conditions. Therefore, in addition to controlling the nature of the terminal chemical functions discussed in the previous examples, the method of the present invention makes it possible to control the structure of the linear organopolysiloxane OL obtained.

[0332] Characterization of the units present at the end of the chains for tests A, B and C:

[0333] Microstructure by NMR 29 If mentioned above also made it possible to identify the units present at the end of the chains during tests A, B and C. In other words, this made it possible to evaluate a possible influence of the order of addition of the cyclic organopolysiloxanes OC on the nature of the units present at the end of the chains. In the table below, the acronym HO-D designates the following unit:

[0334] The acronym (Me)3SiO-D denotes the following unit:

[0335] Similarly, the acronym HO-V designates the following unit:

[0336] Finally, the acronym (Me)3SiO-V designates the following unit:

[0337] The results obtained are mentioned in the table below.

[0338] Thus, with the C4 chain blocker, depending on the implementation of the method of the invention (Test A, B or C), a different distribution of the unit present at the end of the chains is observed. Indeed, the table above shows that the order of addition of the cyclic organopoly siloxane OC strongly influences the nature of the “terminal” unit. Furthermore, the C4 chain blocker allows total control over the nature of the units present at the end of the chains.

Claims

CLAIMS

1. Process for the preparation of linear organopolysiloxanes OL by a ring-opening polymerization reaction, said process comprising the following steps: a) Implementing a ring-opening polymerizable composition S comprising: i) at least one cyclic organopolysiloxane OC having three siloxane units, ii) at least one basic catalyst B of formula (I): in which: -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, -R2 represents a hydrogen atom or a radical -C(=O)-R3 with R3 representing an alkyl group of 1 to 12 carbon atoms; - X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, -n is a natural number between 1 and 6, and iii) at least one chain blocker C; b) Optionally, subsequently adding a chain blocker C identical or different to that of step a) or an acid A to the composition polymerizable by ring opening S, c) Obtaining the linear organopolysiloxane OL.

2. A method according to any one of the preceding claims wherein the cyclic organopolysiloxane OC is represented by the formula (II): in which, R, identical or different, is a radical representing an alkyl group of 1 to 6 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, or an aryl group of 6 to 18 carbon atoms.

3. A process according to any preceding claim, wherein the basic catalyst B is represented by the formula (III): in which: - R1 represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms; - X represents an anion chosen from the group comprising: carboxylates and their derivatives: carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, and n is a natural number between 1 and 6.

4. A process according to any one of the preceding claims, wherein the molar amount of basic catalyst B relative to that of the reaction mixture is from 150 ppm to 4000 ppm, preferably from 250 to 2500 ppm, more preferably from 250 ppm to 1500 ppm relative to that of the reaction mixture.

5. A method according to any one of the preceding claims, wherein the chain blocker C is selected from H2O or compounds of formula (VIII): in which: Y represents a carbon atom or a silicon atom; R is the same or different and represents: -an alkyl group of 1 to 12 carbon atoms, -a cycloalkyl group of 5 to 8 carbon atoms, -an alkenyl group of 2 to 12 carbon atoms containing 1 to 6 unsaturated carbon-carbon bonds, -an aryl group of 6 to 18 carbon atoms, preferably phenyl, -a benzyl group - a siloxyl group having at least 5 units, preferably at least 10 units of formula R 1 c SiO (4-c) / 2 in which R 1identical or different, represents an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably methyl; an aryl group comprising from 6 to 10 carbon atoms, preferably phenyl; and c = 0, 1 or 2 and; said radical R may be substituted or not by an alkyl chain of 1 to 12 carbon atoms, alkenyl of 2 to 6 carbon atoms, a cycloalkyl group of 5 to 8 carbon atoms, an aryl group of 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

6. A method according to any one of the preceding claims, wherein the chain blocker C is an alcohol or a silanol having a pKa of 10 to 16, preferably a pKa of 12 to 16, more preferably a pKa of 14 to 16.

7. Process according to any one of the preceding claims, in which, in step a), the molar ratio of chain blocker C relative to the basic catalyst B used is from 0.01 to 600, preferably from 0.8 to 300, preferentially from 1.5 to 300, preferentially from 4 to 200 and even more preferentially from 8 to 100.

8. A method according to any one of the preceding claims, wherein, in step a), the molar ratio of cyclic organopolysiloxane OC to the chain blocker C employed is from 1 to 20,000, preferably from 2 to 5,000, preferably from 2 to 1,400, preferably from 4 to 700, even more preferably from 4 to 300 and even more preferably from 10 to 150.

9. Method according to any one of the preceding claims, in which, during step b) the molar ratio of cyclic organopolysiloxane OC relative to the chain blocker C used during this step is from 1 to 100, preferably from 10 to 80, preferentially from 10 to 50.

10. Composition SI comprising: i) at least one cyclic organopolysiloxane OC having three siloxane units, ii) at least one basic catalyst B of formula (XII): in which: -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, -R2 represents a hydrogen atom or a radical -C(=O)-Rs with R3 which represents an alkyl group of 1 to 12 carbon atoms; - X represents an anion chosen from the group comprising: carboxylates and their derivatives, carbonates and their derivatives, hydroxyl, siloxanolates, silanolates, and n is a natural number between 1 and 6, and iii) at least one chain blocker C.

11. Catalysts B represented by formula (XIV): in which: -R1 identical or different represents an alkyl chain of 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms; -X represents a siloxanolate or silanolate anion and n is a natural number between 1 and 6.

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