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EP-4739730-A1 - METHOD FOR POLYMERIZATION BY MEANS OF RING-OPENING OR POLYCONDENSATION

EP4739730A1EP 4739730 A1EP4739730 A1EP 4739730A1EP-4739730-A1

Abstract

The invention relates to a method for producing linear organopolysiloxanes OL by means of a polymerization reaction from organopolysiloxanes O (cyclic and/or linear), and using a catalytic system AI. More precisely, the method of the present invention can be used to obtain linear organopolysiloxanes OL having a controlled molar mass and with a very low level of residual cyclic organopolysiloxanes. The present application also relates to the linear organopolysiloxane OL obtained according to the various embodiments of the method of the present invention described.

Inventors

  • BOULEGUE-MONDIERE, Aurélie
  • BLANC, DELPHINE
  • PARISOT, Hervé
  • KATO, TSUYOSHI
  • SHI, Limiao
  • BACEIREDO, ANTOINE

Assignees

  • Elkem Silicones France SAS
  • CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE

Dates

Publication Date
20260513
Application Date
20240704

Claims (9)

  1. [Claim 1] Process for the preparation of linear organopolysiloxanes OL by a polymerization reaction of at least one organopolysiloxane O, in the presence of a catalytic system AI comprising: - at least one catalyst A of formula (I): in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising from 5 to 8 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, R3 identical or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, - or the two R3 groups together with the atoms to which they are linked form a cyclic hydrocarbon group such as a cycloalkyl of 5 to 8 carbon atoms or a phenyl. and optionally at least one initiator I.
  2. [Claim 2] Method according to claim 1 in which the organopolysiloxane O is chosen from: a linear organopolysiloxane alone or in mixtures, a cyclic organopolysiloxane alone or in mixtures, or even a mixture of one or more linear and cyclic organopolysiloxanes.
  3. [Claim 3] A process according to claim 1 or 2, wherein catalyst A is represented by the following formula (VI): in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl group or a phenyl.
  4. [Claim 4] Process according to any one of the preceding claims, in which the molar quantity of catalyst A relative to the organopolysiloxane O is from 0.005% to 2%, preferably from 0.01 to 2%, preferentially from 0.05 to 1%, and even more preferentially from 0.1 to 0.5%.
  5. [Claim 5] A process according to any preceding claim, wherein the initiator I is selected from water or compounds of formula (VIII): Formula VIII in which: Y represents a carbon or silicon atom, R is the same or different and represents: -a hydrogen atom - an alkyl group comprising from 1 to 12 carbon atoms, - a cycloalkyl group comprising from 5 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, - a benzyl group or a phenyl, when said radical R may be substituted or not by an alkyl group comprising from 1 to 12 carbon atoms, an alkenyl group comprising from 2 to 6 carbon atoms, a cycloalkyl group comprising from 5 to 8 carbon atoms, an aryl group comprising from 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.
  6. [Claim 6] Process according to any one of the preceding claims, in which the molar ratio of initiator I relative to catalyst A is from 0 to 20, preferably from 0 to 10, preferably from 0 to 5, preferentially from 0 to 2.
  7. [Claim 7] A method according to any preceding claim, wherein during the polymerization reaction of at least one organopolysiloxane O at least one chain blocker C represented by the formula (X) is added: Formula X in which, R 1, identical or different, represents CH3 or phenyl, preferably CH3; R 2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -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-Cs)alkyl-CF3, the alkyl being linear or branched, - a C5-C10 cycloalkyl group, optionally substituted, - a CÔ-CIS aryl group, optionally substituted, or -a hydrogen atom; and q is an integer between 1 and 50, preferably between 1 and 20, more preferably between 1 and 10.
  8. [Claim 8] A process according to any preceding claim, wherein the molar ratio of chain blocker C relative to catalyst A is from 0 to 30, preferably from 0 to 20, and more preferably from 0 to 10.
  9. [Claim 9] Composition for implementing the method defined according to claims 1 to 7 comprising: - at least one cyclic organopolysiloxane O as defined in claim 1 or 2, - a catalytic system AI as defined in claim 1, 3, 4, 5 or 6 and optionally a chain blocker C as defined in claim 7 or 8.

Description

Title of the invention: Cycle-opening or polycondensation polymerization process Technical field: The invention relates to a process for preparing linear organopolysiloxanes OL by a polymerization reaction from organopolysiloxanes O (cyclic and/or linear), and using a catalytic system AI. More precisely, the process of the present invention makes it possible to obtain linear organopolysiloxanes OL of controlled molar mass with a very low level of residual cyclic organopolysiloxanes. The invention also relates to the catalysts used in the AI catalytic system which will be detailed in detail below. Technological background: A major challenge for the silicone industry in the coming years is to industrially synthesize organopolysiloxanes with a very low or even zero residual cyclic rate. To date, the industrial synthesis of organopolysiloxanes by polycondensation or by ring-opening polymerization sees the formation of cyclic organopolysiloxanes such as octamethyltetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) or other unwanted cyclic organopolysiloxanes. In conventional industrial processes, ring-opening polymerization is preferred because it uses monomers that are easily synthesized, purifiable and therefore inexpensive. However, this method is also confronted with the presence of unwanted cyclic products that can amount to a content of between 6 and 15% relative to the total mass of linear organopolysiloxane obtained during the synthesis, which corresponds to thermodynamic equilibrium. Traditionally, this high cyclic product content requires energy-intensive process steps such as a high-temperature and/or reduced-pressure devolatilization step to separate these by-products from the resulting linear organopolysiloxane. Avoiding these steps improves production efficiency and reduces carbon dioxide emissions, thereby producing a more environmentally friendly silicone product. Thus, in the interests of economic and energy profitability, there is a need to develop new solutions to avoid or at least limit these long and costly separation stages. 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 the European regulation 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 application of silicones such as the electronics industry for example. Therefore, there is a need to develop processes for providing linear organopolysiloxanes free of or at least having a low content of cyclic silicones. In particular, there is an interest in providing a new catalytic system for implementing such a process. 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. N-heterocyclic olefins (NHO) are highly polarized olefins due to their N-heterocyclic aromatic structure. They have a strong basic and nucleophilic character and are therefore interesting molecules as organic catalysts. Indeed, patent applications CN106750227 and CN109851765 describe the use of such catalysts for the ring-opening polymerization reaction of various cyclic monomers such as epoxides or cyclic esters. Thus, one of the essential objectives of the invention is to carry out a polymerization reaction from organopolysiloxanes O (cyclic and/or linear), and using N-heterocyclic olefins. This invention will therefore aim to improve the preparation of organopolysiloxane by ring-opening polymerization reaction or by polycondensation, by means of a catalytic system which is more efficient than those used previously and which makes it possible to obtain higher yields of linear organopolysiloxane while limiting the formation of cyclic organopolysiloxanes by retroscission reaction. The development of this alternative technology allows the manufacture of more environmentally friendly silicone. Summary of the invention: Surprisingly, the Applicant has developed a catalytic system that meets these expectations. Thus, the present invention relates to a process for preparing linear organopolysiloxanes OL by a polymerization reaction of at least one organopolysiloxane O, in the presence of a catalytic system AI comprising: -at least one catalyst A of formula (I): in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising 5 to 8 carb