Method for producing organopolysiloxanes having (meth)acrylate functional groups

Abstract

The present invention relates to a method for preparing a composition X comprising at least one organopolysiloxane A containing at least one (meth)acrylate group, the method comprising the following steps: a) reacting at least one organopolysiloxane E containing at least one epoxy group with acrylic acid or methacrylic acid or a mixture thereof at a temperature of 50°C to 130°C, preferably 70°C to 130°C, more preferably 90°C to 125°C, in the presence of: - a catalyst C [CR(L) - a complex of chromium in the (III) oxidized state represented by the following formula (1) 1 )3](1), in the formula, the symbol L 1 a) which may be the same or different, represents a β-diketonate anion and is a polymerization inhibitor of acrylic acid or methacrylic acid; b) defoliate the reaction medium obtained at the end of step a); c) obtain composition X comprising at least one organopolysiloxane A.

Description

[Technical Field]

[0001] This invention relates to a method for producing organopolysiloxanes containing (meth)acrylate functional groups, preferably acrylate functional groups. Throughout this document, it should be understood that (meth)acrylate groups include acrylate groups, methacrylate groups, or mixtures thereof. These (meth)acrylate functional groups are present only on organic groups bonded to the polysiloxane chain by Si-C bonds (which may be present in the chain, at the chain ends, or both). These (meth)acrylic acid ester functional groups can react according to radical pathways, thermal activation, and / or radiation-induced polyaddition polymerization mechanisms.

[0002] These organopolysiloxanes containing (meth)acrylate functional groups are widely used in radically crosslinkable silicone compositions and, if necessary, can be coated as thin films onto flexible supports made of textiles, paper, polyvinyl chloride (PVC), polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate (PET), polyurethane, or nonwoven glass fibers to produce elastomers. [Background technology]

[0003] Coating flexible supports with silicone compounds has a variety of applications. For example, if the flexible support is made of fiber, water repellency is required. If the support is made of polymers such as paper, PVC, or PET, non-stick properties are usually required.

[0004] Nonstick coatings are useful in many applications where a surface or material normally adheres to other materials, but needs to be non-adherent to other materials. For example, silicone compositions are used as coatings for non-stick paper and can therefore be combined with adhesive elements that can be easily peeled off without losing their adhesive properties, such as pressure-sensitive adhesives for labels, decorative laminates, and transfer tapes. Silicone-based nonstick coatings applied to paper, polyethylene, polypropylene, polyester, and other supports of this type are also used as nonstick surfaces for food products, particularly in the industrial packaging sector.

[0005] As a result, these organopolysiloxanes containing (meth)acrylate functional groups have long attracted considerable interest, and their production methods can be envisioned using various methods described in the prior art.

[0006] In recent years, there has been growing interest in using such organopolysiloxanes in various photopolymerization-based additive manufacturing methods to obtain silicone elastomer products. Notable methods include laser lithography (SLA), digital photopolymerization (DLP) 3D printing, and continuous liquid-phase interface fabrication (CLIP). Silicone elastomer products obtained by these methods possess excellent mechanical properties.

[0007] Such organopolysiloxanes having (meth)acrylate functional groups are known to be industrially obtained by the reaction of an epoxy-functionalized organopolysiloxane with (meth)acrylic acid in the presence of a chromium-based catalyst.

[0008] Patent EP1276825-B1 teaches, in particular, the production of organopolysiloxanes containing (meth)acrylate functional groups from an organopolysiloxane having epoxy functional groups and acrylic acid in the presence of chromium(III) acetate and two solvents, one of which is an alcohol. When carrying out this process described in patent EP1276825 B1, these solvents are necessary to solubilize the chromium(III) acetate catalyst. Furthermore, the yield and selectivity of this process can be improved. Furthermore, compositions containing organopolysiloxanes containing acrylate functional groups obtained according to the teachings of this patent have an unpleasant odor for the users of these compositions.

[0009] Recently, patent application WO2017187030 teaches a process for producing organopolysiloxanes containing (meth)acrylate functional groups from an organopolysiloxane having epoxy functional groups, acrylic acid, chromium(III) acetate and a solvent, in the absence of an alcohol solvent. This patent application WO2017187030 shows the advantage that the yield of organopolysiloxanes having (meth)acrylate functional groups can be improved. Furthermore, this method makes it possible to obtain an oil without an unpleasant odor within a time suitable for industrial production. However, if there is an organopolysiloxane oil having epoxy functional groups with a low epoxy functional group content, the implementation of this process can become complicated. A decrease in the yield and selectivity of such compounds is observed. This decrease in reactivity is explained, in particular, by the low solubility of the chromium acetate catalyst under such conditions. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0010] For the purposes of the present application, the epoxy functional group content is understood to be measured by the number of moles of epoxy functional groups per kilogram of polyorganosiloxane oil.

[0011] To limit this decrease in reactivity, the reaction medium can be preheated to promote catalyst solubilization, or the reactants can be introduced at various stages of the process. However, these adjustments to the process may lead to a decrease in the reaction rate, and consequently, an increase in the reaction time required to form organopolysiloxanes containing (meth)acrylate functional groups.

[0012] With the aim of improving this process, one of the key objectives of the present invention is to develop a process for producing organopolysiloxanes containing (meth)acrylate functional groups with satisfactory kinetics and selectivity without using alcohol solvents.

[0013] Another important object of the present invention is to provide a robust process for producing organopolysiloxanes containing (meth)acrylate functional groups from organopolysiloxane oils having various chain lengths and / or various levels of acrylate functional groups.

[0014] Another important objective of the present invention is to provide a catalyst system suitable for the method of the present invention.

[0015] Another important objective of the present invention is to provide a robust method for producing organopolysiloxanes containing (meth)acrylate functional groups by a "one-pot" reaction.

[0016] In this invention, the term "one-pot" is understood to mean that all reactants are introduced into the reactor at the initial time of the reaction (also called t0).

[0017] In this invention, the weight percentage of compound A is understood to mean the weight percentage of this chemical species A relative to the total weight of the mixture. [Means for solving the problem]

[0018] And, surprisingly, the applicant has developed a process for preparing composition X comprising at least one organopolysiloxane A containing at least one (meth)acrylate group. This process includes the following steps: a) At a temperature of 50°C to 130°C, preferably 70°C to 130°C, and more preferably 90°C to 125°C, at least one organopolysiloxane E containing at least one epoxy group is reacted with acrylic acid or methacrylic acid or a mixture thereof in the presence of the following: -The catalyst C[CR(L) is a complex of chromium in the (III) oxidized state represented by the following formula (1) 1 )3](1) Here, the symbol L 1 These may be the same or different, and represent a β-diketonate anion, and - Polymerization inhibitors of acrylic acid or methacrylic acid; b) Devolve the reaction medium obtained at the end of step a); c) Obtain the composition X comprising at least one organopolysiloxane A.

[0019] Step a) of the method for producing composition X according to the present invention is preferably carried out in the presence of a solvent S that is not an alcohol.

[0020] Therefore, preferably, the present invention is carried out in the absence of alcohol, and particularly in the absence of butanol.

[0021] In this invention, the term "solvent" is understood to mean a non-reactive solvent. Therefore, solvent S is different from organopolysiloxane E, acrylic acid, and methacrylic acid. [Effects of the Invention]

[0022] The method for producing composition X according to the present invention has the advantage of obtaining satisfactory yield and selectivity of organopolysiloxane A. The inventors have demonstrated that, as a result of experience, better selectivity for organopolysiloxane A can be obtained by carrying out the process in the presence of a chromium(III) β-diketnate complex, such as chromium(III) acetylacetonate. Furthermore, this process has the advantage of being adaptable on an industrial scale to organopolysiloxane E with various degrees of polymerization and / or various levels of epoxy functional groups, without the need to adapt the process implementation. Therefore, the method according to the present invention can be carried out as a "one-pot" reaction starting from a pre-prepared composition X, such as a premix of composition X prepared the day before. This significant advantage makes it easy to carry out the process on an industrial scale.

[0023] The aforementioned advantages are explained by the improved solubility of the catalyst in the reaction medium. Therefore, the catalyst dissolves completely in composition X and does not precipitate during storage of composition X prepared before the process or during its execution.

[0024] Another advantage of the process is, for example, that the resulting composition X does not have an unpleasant odor. Alternatively, in step a) of the method, a conversion rate of epoxy groups exceeding 98% can be obtained within 6 hours. [Modes for carrying out the invention]

[0025] According to a preferred embodiment of the present invention, if the temperature in step a) is between 90°C and 125°C, the duration of step a) is between 1 hour and 5 hours.

[0026] The organopolysiloxane A obtained by the method of the present invention comprises the following siloxyl units (I), (II), and optionally (III): [ka] During the ceremony, -a=1 or 2, b=0, 1, or 2 and a+b=1, 2, or 3, -c=0, 1, 2, or 3, -d=1 or 2, e=0, 1, or 2 and d+e=1, 2, or 3, -The symbol Y may be the same or different, and represents an organic group that includes an epoxy group and optionally includes one or more heteroatoms such as oxygen atoms, wherein the organic group Y preferably has 2 to 20 carbon atoms, and more preferably Y is selected from the group consisting of alkyl glycidyl ethers, linear, branched or cyclic epoxyalkyls, linear, branched or cyclic epoxyalkenyls, and glycidyl carboxylates. -Symbol Z 1 and Z 2 These may be the same or different, and represent a monovalent organic group having 1 to 30 carbon atoms, preferably selected from the group consisting of alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, and more preferably selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl, and phenyl groups. -The symbol V may be the same or different, and represents an organic group containing a (meth)acrylate group, and the organic group V preferably has 5 to 23 carbon atoms. - The organopolysiloxane A contains at least two silicon atoms and at least one siloxyl unit (III) per molecule.

[0027] Organopolysiloxane E contains the following siloxy units (I) and (II): [ka] During the ceremony, -a=1 or 2, b=0, 1, or 2, and a+b=1, 2, or 3, -c=0, 1, 2, or 3, -The symbol Y may be the same or different, and represents an organic group that includes an epoxy group and optionally includes one or more heteroatoms such as oxygen atoms, wherein the organic group Y preferably has 2 to 20 carbon atoms, and more preferably Y is selected from the group consisting of alkyl glycidyl ethers, linear, branched or cyclic epoxyalkyls, linear, branched or cyclic epoxyalkenyls, and glycidyl carboxylates. -Symbol Z 1 and Z 2 These may be the same or different, and represent a monovalent organic group having 1 to 30 carbon atoms, preferably selected from the group consisting of alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, and more preferably selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl, and phenyl groups. - The organopolysiloxane E contains at least two silicon atoms and at least one siloxy unit (I) per molecule.

[0028] Preferably, in the case of a siloxyl unit (I), the symbol Y is selected from the group consisting of organic groups (IV) to (VIII) of the following formula: [ka]

[0029] In one particularly preferred embodiment, in the siloxyl unit (I), the symbol Y is the organic group (VII) of the following formula:

[0030] [ka]

[0031] These organopolysiloxane E can have a linear, branched, or cyclic structure, and their degree of polymerization is 2 to 5000, preferably 2 to 1000, and more preferably 2 to 500.

[0032] Preferably, the organopolysiloxane E has a linear structure and contains siloxyl units (I) and (II) of the following formula: [Chemical Formula] In the formula, - a = 1 or 2, b = 0, 1, or 2, and a + b = 2 or 3, - c = 2 or 3, - The symbol Y may be the same or different and represents an organic group containing an epoxy group and optionally one or more heteroatoms such as an oxygen atom. The organic group Y preferably has 2 to 20 carbon atoms, and more preferably, Y is selected from the group consisting of alkyl glycidyl ethers, linear, branched or cyclic epoxyalkyls, linear, branched or cyclic epoxyalkenyls, and carboxylic acid glycidyl esters, - The symbol Z 1 and Z 2 may be the same or different and represent a monovalent organic group having 1 to 30 carbon atoms, preferably selected from the group consisting of an alkyl group having 1 to 8 carbon atoms and an aryl group having 6 to 12 carbon atoms, and more preferably selected from the group consisting of methyl, ethyl, propyl, 3,3,3 - trifluoropropyl, xylyl, tolyl, and phenyl groups, - The organopolysiloxane E contains at least 2 silicon atoms and at least 1 siloxyl unit (I) per molecule.

[0033] In the case of a linear polymer, the organopolysiloxane E is a siloxyl unit "D" selected from the group consisting of Y2SiO 2 / 2 , YZ 1 SiO 2 / 2 , and Z 2 2SiO 2 / 2 , and a siloxyl unit Y3SiO 1 / 2 , YZ 1 2SiO 1 / 2 , Y2Z 1 SiO 1 / 2 , and Z 2 3SiO 1 / 2Essentially composed of a siloxyl unit "M" selected from the group consisting of Y, Z. 1 , and Z 2 This is as stated above.

[0034] According to a preferred embodiment of the present invention, organopolysiloxane E is a siloxy unit YZ 1 SiO 2 / 2 and Z 2 2SiO 2 / 2 A siloxyl unit "D" selected from the group consisting of and a siloxyl unit YZ 1 2SiO 1 / 2 and Z 2 3SiO 1 / 2 Essentially composed of a siloxyl unit "M" selected from the group consisting of Y, Z. 1 and Z 2 This is as stated above.

[0035] Organopolysiloxane E has a kinematic viscosity at 25°C of 1 to 100,000 mPa·s, preferably 10 to 50,000 mPa·s, more preferably 10 to 10,000 mPa·s, and even more preferably 10 to 5,000 mPa·s.

[0036] All viscosities considered in this application correspond to "Newtonian" kinematic viscosity at 25°C, that is, kinematic viscosity measured using a Brookfield viscometer in a self-known manner at a shear rate gradient low enough that the measured viscosity does not depend on the velocity gradient.

[0037] According to a preferred embodiment of the present invention, organopolysiloxane E contains 1 to 300 siloxy units (I) having at least one organic group including an epoxy group per molecule. According to a preferred embodiment of the present invention, organopolysiloxane E contains 2 to 250 siloxy units (I) per molecule, and more preferably, organopolysiloxane E contains 20 to 300 siloxy units (I) per molecule.

[0038] According to another embodiment, organopolysiloxane E contains 0.5% to 30% by weight, preferably 1% to 20% by weight, and more preferably 1% to 10% by weight, of the organic group Y containing an epoxy group, based on the total weight of organopolysiloxane E.

[0039] According to one embodiment, the content of the organic group Y containing the epoxy group is 0.05 to 3 moles per kilogram of organopolysiloxane E, preferably 0.1 to 1.5 moles, and more preferably 0.1 to 1 mole per kilogram of organopolysiloxane E.

[0040] According to a preferred embodiment of the method of the present invention, organopolysiloxane E is selected from the compounds of the following formulas (EI) to (E-IV): [ka] In formula (EI), R is an alkyl group containing 2 to 5 carbon atoms, a is 2 to 50, preferably 2 to 15, and b is 20 to 400. [ka] In equation (E-II), n is between 0 and 250. [ka] In equation (E-III), x is between 10 and 300, and y is between 2 and 30, preferably between 2 and 15. [ka] In equation (E-IV), x ranges from 0 to 250.

[0041] Depending on the intended use of organopolysiloxane A, complete or partial conversion of the epoxy functional groups of organopolysiloxane E may be desired. Thus, it is possible to obtain organopolysiloxane A containing epoxy and (meth)acrylate functional groups that can be used, for example, as an adhesion modifier or adhesion promoter, or organopolysiloxane A containing only or essentially (meth)acrylate functional groups that can be used, for example, as an essential component of a radical crosslinkable silicone composition for producing elastomers. The molar ratio R between (meth)acrylic acid and the epoxy functional groups of organopolysiloxane E used in the process is adjusted accordingly.

[0042] According to one embodiment of the method according to the present invention, in step a), the molar ratio R of (meth)acrylic acid to the epoxy group of organopolysiloxane E is greater than 1.05, preferably 1.05 to 15, and more preferably 1.05 to 10.

[0043] Throughout this document, (meth)acrylic acid includes both acrylic acid and methacrylic acid.

[0044] According to a preferred embodiment of the method according to the present invention, in step a), the molar ratio R between the acrylic acid and the epoxy group of organopolysiloxane E is greater than 1.05, preferably 1.05 to 15, and more preferably 1.05 to 10.

[0045] Catalyst C is a chromium complex in the (III) oxidation state.

[0046] Catalyst C is a chromium complex represented by the following equation (1). [Cr(L 1 )3] (1) In the formula, the symbol L 1 These are identical or different ligands representing a β-diketonate anion.

[0047] Preferably, catalyst C is a chromium complex represented by the following formula (1). [Cr(L1 )3] (1) In the formula, the symbol L 1 These are identical or different ligands representing the β-diketonate anion shown in formula (V) below. [ka] In the formula, R1 and R3 may be the same or different, and C1~C 30 C6-C hydrocarbon group containing aromatic ring 30 It represents a hydrocarbon group, or R1 and R3, together with the atoms to which they are bonded, form a monoring consisting of 6 to 10 carbon atoms. R2 is hydrogen or C1~C 30 It is a hydrocarbon group, or it forms a monoring consisting of 5 to 10 atoms together with the atom to which R1 and R2 are bonded, and

[0048] According to a preferred embodiment, the same or different ligands L1 represent a β-diketonate anion represented by the following formula (2). [ka] In the formula, R1 and R3 are independent of each other, C1~C 30 C6-C containing hydrocarbon groups or aromatic rings 30 It represents the hydrocarbon group, R2 is hydrogen or C1~C 30 It is a hydrocarbon group.

[0049] According to one embodiment of the present invention, catalyst C is a chromium(III) complex represented by the following formula (1). [Cr(L 1 )3] (1) In the formula, the symbol L 1These are identical or different ligands, representing the following: β-diketonate anions, e.g., 2,4-pentanedione; 2,4-hexanedione; 2,4-heptanedione; 2,4-octanedione; 2,4-nonanedione; 2,4-decanedione; 2,4-undecanedione; 2,4-dodecanedione; 3,5-heptanedione; 3-ethyl-2,4-pentanedione; 5-methyl-2,4-hexanedione; 3,5-octanedione; 5,5-dimethyl-2,4-hexanedione; 6-methyl-2,4-heptanedione; 2,2-dimethyl-3,5-nonanedione; 2,6-dimethyl-3,5-heptanedione; 2-acetylcyclohexanone (Cy-acac); 2,2,6,6-tetramethyl-3,5- Heptanedione (t-Bu-acac); 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (F-acac); benzoylacetone; dibenzoylmethane; 3-methyl-2,4-pentadione; 3-acetylpentan-2-one; 3-acetyl-2-hexanone; 3-acetyl-2-heptanone; 3-acetyl-5-methyl-2-hexanone; stearoylbenzoylmethane; 4-t-butyl-4'-methoxydibenzoylmethane; 4,4'-dimethoxydibenzoylmethane, 4,4'-di-tert-butyldibenzoylmethane; 2,2,6,6-tetramethyl-3,5-heptanedione, or stearoylbenzoylmethane or 1-phenyl-3-eicosanedione β-diketone.

[0050] Preferably, catalyst C is a chromium complex represented by the following formula (1). [Cr(L 1 )3] (1) In the formula, the symbol L 1 These are identical or different ligands representing the β-diketonate anion shown in formula (3) below. [ka] In the formula, R may be the same or different, C1~C 30 C6-C containing hydrocarbon groups or aromatic rings 30 It represents the hydrocarbon group.

[0051] In a particularly advantageous embodiment, catalyst C is a β-diketnate of chromium in the (III) oxidation state, selected from the group consisting of chromium(III) acetylacetonate (2,4-pentanedione), chromium(III) hexafluoroacetylacetonate (1,1,1,5,5,5-hexafluoro-2,4-pentanedione (F-acac)), chromium(III) 2,2,6,6-tetramethyl-3,5-heptanedione, chromium(III) 3,5-heptanedione, and chromium(III) 2,2,7-trimethyl-3,5-octanedionate.

[0052] According to another embodiment of the process of the present invention, chromium(III)β-diketnate can be produced in situ.

[0053] According to one embodiment, the concentration of catalyst C is 0.05% to 1%, preferably 0.05% to 0.5%, more preferably 0.05% to 0.3%, and even more preferably 0.05% to 0.25%, expressed as a mole percent relative to the epoxy groups of organopolysiloxane E.

[0054] Another advantage of the method according to the present invention is that a small amount of catalyst can be used.

[0055] According to one embodiment of the method of the present invention, the method is carried out without solvent S.

[0056] According to a preferred embodiment of the present invention, the method is characterized in that, in step a), composition X also contains at least one solvent S selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, toluene, xylene, chlorobenzene, and mixtures thereof.

[0057] Preferably, the method according to the present invention does not contain any solvent other than solvent S selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, toluene, xylene, chlorobenzene, and mixtures thereof.

[0058] According to one embodiment of the method according to the present invention, the content of solvent S used in step a) of the above method is 0 to 15% by weight, preferably 2 to 15% by weight, and more preferably 4 to 12% by weight, based on the total weight of the reaction medium used in step a).

[0059] However, if the amount of solvent S exceeds 15% by weight relative to the total weight of the reaction medium used in step a) of the method of the present invention, the reaction time required to achieve a conversion rate of epoxy groups exceeding 98% increases. Therefore, it is important to find a suitable compromise between the solubilization of the system and the reaction kinetics.

[0060] According to one embodiment of the present invention, in step a), the catalyst C, the polymerization inhibitor of (meth)acrylic acid, the solvent S, and part or all of the (meth)acrylic acid can be pre-mixed before adding the organopolysiloxane E.

[0061] According to a preferred embodiment of the present invention, in step a), before carrying out the method of the present invention, catalyst C, polymerization inhibitor of (meth)acrylic acid, solvent S, all of the (meth)acrylic acid, and organopolysiloxane E can be pre-mixed to form a premix. For example, this premix can be prepared the day before it is used in the process of the present invention. This embodiment is particularly advantageous in that it makes the process of the present invention flexible and especially suitable for industrial scale.

[0062] In the method according to the present invention, a polymerization inhibitor for (meth)acrylic acid is introduced in step a). Polymerization inhibitors for (meth)acrylic acid are widely known and include, for example, phenol compounds such as 4-methoxyphenol, hydroquinone, methylhydroquinone, or alkyldiphenylamines such as phenothiazine. Preferably, hydroquinone methyl ether (MEHQ) or 4-methoxyphenol is used as the polymerization inhibitor for (meth)acrylic acid. According to a preferred embodiment, the amount of polymerization inhibitor used is 0.01% to 1% of the weight of organopolysiloxane E, and more preferably 0.01% to 0.5% of the weight of organopolysiloxane E.

[0063] In step b) of the method according to the present invention, volatile components are removed from the reaction medium obtained at the end of step a). For this purpose, the reaction medium from step a) is heated under reduced pressure to a temperature of 80°C to 130°C. This defoliation step allows the solvent S and excess (meth)acrylic acid to be evaporated. The solvent S used in the method of the present invention is recyclable.

[0064] According to another embodiment, the filtration step may be performed before or after step b). Preferably, if a filtration step is added to the method according to the present invention, the filtration step is performed after step b).

[0065] According to another embodiment of the present invention, the process according to the present invention consists of the following steps. a) At a temperature of 70°C to 130°C, preferably 90°C to 130°C, more preferably 100°C to 125°C, at least one organopolysiloxane E containing at least one epoxy group is reacted with acrylic acid or methacrylic acid or a mixture thereof in the absence of a solvent and in the presence of the following: -The catalyst C [CR(L) is a complex of chromium in the (III) oxidized state represented by the following formula (1) 1 )3] (1) In the formula, the symbol L 1These may be the same or different, and represent a β-diketonate anion. - In step a), at least 4% by weight of solvent S relative to the total weight of the reaction medium, - Polymerization inhibitors of acrylic acid or methacrylic acid; b) Devolve the reaction medium obtained at the end of step a); c) Optionally, filter the reaction medium obtained at the end of step b); and d) Obtain the composition X comprising at least one organopolysiloxane A.

[0066] During the process, steps a) and b) can be carried out under an inert atmosphere, but this is not required. According to a preferred embodiment, when a phenol compound is used as a (meth)acrylic acid inhibitor, steps a) and b) of the process are carried out in air, and more preferably under bubbling of dry air.

[0067] Another subject of the present invention relates to composition X obtained by the method described above.

[0068] Another subject of the present invention relates to a method for manufacturing a coating on a substrate, comprising the following steps. a) Prepare composition X according to the method described above; b) Prepare a radical crosslinkable silicone composition W containing the following components: i. The composition X, ii. Photoinitiator, and iii. At least one additive of optional choice; c) The composition W is applied to the substrate; d) Crosslink the composition W by exposing it to radiation.

[0069] Preferably, the substrate is a flexible support made from textiles, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or nonwoven glass fibers.

[0070] According to a preferred embodiment of the present invention, in step d), the radiation is ultraviolet light having a wavelength of less than 420 nm. Examples of radiation sources include light sources such as point sources of ultraviolet or visible light, such as light-emitting diodes (commonly known as LEDs).

[0071] In a particular embodiment of this method, the irradiation source is a block of light-emitting diodes (LEDs), preferably a block of light-emitting diodes (LEDs) having wavelengths of 355, 365, 385, or 405 nm. The output of the irradiation source is at least 1, 10, or 50 mW / cm². 2 This can be achieved. 1~1000mW / cm 2 It may be in the range of 1 to 200 mW / cm², preferably 1 to 200 mW / cm². 2 More preferably 1 to 50 mW / cm² 2 More preferably 1 to 20 mW / cm² 2 It is within the range of [the specified range].

[0072] The irradiation time is short, usually less than 1 second, and especially for thin coatings, it is about a few hundredths of a second. Excellent crosslinking effect can be obtained without heating.

[0073] According to another embodiment, the crosslinking step d) is performed at a temperature of 40°C to 100°C.

[0074] Of course, the curing time can be adjusted in particular by the number of lamps used, the UV irradiation time, the wavelength of the lamps, and the distance between the composition and the lamps. The amount of composition W applied to the substrate varies, but is usually 1 m² of the treated surface. 2 0.1~5g / 1m 2 This is within the range. The application amount varies depending on the properties of the substrate and the required non-stick properties. Typically, it is 0.5 to 1.5 g / m². 2 That is the case.

[0075] This process is particularly suitable for applying non-stick silicone coatings to flexible supports such as fibers, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or glass nonwoven fabrics. These coatings are particularly suitable for use in non-stick applications.

[0076] To polymerize organopolysiloxanes having (meth)acrylate functional groups, those skilled in the art can select a suitable radical photoinitiator that absorbs light emission having a wavelength less than 420 nm. Examples of radical photoinitiators include α-hydroxyketones, benzoin ethers, and aromatic α-aminoketones. Examples of radical photoinitiators include the following products in particular: isopropylthioxanthone; benzophenone; camphorquinone; 9-xanthenone; anthraquinone; 1,4-dihydroxyanthraquinone; 2-methylanthraquinone; 2,2'-bis(3-hydroxy-1,4-naphthoquinone); 2,6-dihydroxyanthraquinone; 1-hydroxycyclohexylphenyl ketone; 1,5-dihydroxyanthraquinone; 1,3-diphenyl-1,3-propanedione; 5,7-dihydroxyflavone; dibenzoyl peroxide; 2-benzoylbenzoic acid; 2-hydroxy-2-methylpropiophenone; 2-phenylacetophenone; 2,4,6-trimethylbenzoyl diphosphate Phenylphosphine oxides and their derivatives; anthron; bis(2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide; 4,4'-dimethoxybenzoin; phenanthrenequinone; 2-ethylanthraquinone; 2-methylanthraquinone; 1,8-dihydroxyanthraquinone; dibenzoyl peroxide; 2,2-dimethoxy-2-phenylacetophenone; benzoin; 2-hydroxy-2-methylpropiophenone; benzaldehyde; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-methylpropyl)ketone; benzoylacetone; ethyl(2,4,6-trimethylbenzoyl)phenylphosphine; and mixtures thereof.

[0077] Examples of commercially available radical photoinitiators include Irgacure® 369, Irgacure® 651, Irgacure® 907, and Darocure® 1173, all sold by Ciba-Geigy.

[0078] The amount of photoinitiator in composition W is generally in the range of 0.001% to 5%, and usually 0.005% to 3%, relative to the total weight of composition W.

[0079] As an additive, the composition may include at least one additive to adjust the peeling force of the silicone / adhesive interface, which can be selected from the following: (i) Organic (meth)acrylate derivatives, and (ii) Silicone having (meth)acrylate functional groups.

[0080] Particularly suitable organic (meth)acrylate derivatives include epoxidized (meth)acrylate, (meth)acryloglyceropolyester, (meth)acrylourethane, (meth)acrylopolyether, (meth)acrylopolyester, and (meth)acryloacrylic compounds.

[0081] Trimethylolpropane triacrylate, tripropylene glycol diacrylate, and pentaerythritol tetraacrylate are particularly preferred.

[0082] According to a preferred modification of the present invention, the additive used is a silicone having a (meth)acrylate functional group. Representative examples of (meth)acrylate functional groups that are particularly suitable for the present invention and that are present in silicone include derivatives of acrylates, methacrylates, (meth)acrylate ethers, and meth(acrylate) esters bonded to a polysiloxane chain by Si-C bonds. Such acrylate derivatives are described in particular in Japanese Patents EP281718, FR2632960, and EP940458.

[0083] Other additives, such as thiols and aromatic amines, may be added to promote crosslinking of composition W.

[0084] Therefore, another subject of the present invention relates to a substrate having at least one coating which can be obtained according to the method described above.

[0085] Another object of the present invention is a method for producing an elastomer product by additive manufacturing, comprising the following steps: a) Prepare composition X according to the method described above; b) Use an irradiation source and a photocrosslinkable silicone composition W2 containing the following: i. The composition X, ii. Photoinitiator, and iii. At least one additive of optional choice; c) Selectively irradiate at least a portion of the photocrosslinkable silicone composition W2 using an irradiation source to form a portion of the silicone elastomer product; and d) Repeat step ii) a sufficient number of times to manufacture the silicone elastomer product.

[0086] Advantageously, additive manufacturing methods include, in particular, laser 3D printing (SLA), digitally charged photopolymerization (DLP), or vat photopolymerization by continuous liquid interface fabrication (CLIP) printing. These techniques and related equipment are well known to those skilled in the art, and they can select the appropriate techniques and corresponding 3D printers. These techniques and equipment are described in documents such as, for example, WO2015 / 197495, US5236637, WO2016 / 181149, and WO2014 / 126837.

[0087] Suitable irradiation sources include mercury lamps, which are commonly used in the photopolymerization reactions of silicone compositions. In a particular embodiment of this method, the irradiation source is an LED lamp, preferably an LED lamp having a wavelength of 355, 365, 385, or 405 nm.

[0088] The properties of the photoinitiator and any additives used in the photocrosslinkable composition W2 are the same as those described above for composition W. However, the photocrosslinkable silicone composition W2 may also contain a filler D. The filler D makes it possible to improve the mechanical properties of the silicone elastomer product obtained at the completion of the method while maintaining good elastomer properties. In particular, the filler D makes it possible to maintain a high elongation at break while improving the elastic modulus at break of the resulting silicone elastomer product.

[0089] The ultimate subject of the present invention relates to a silicone elastomer product obtained according to the additive manufacturing process described above. [Examples]

[0090] Organopolysiloxane E used in the examples: Organopolysiloxane E1: [ka] Organopolysiloxane E2: [ka] Organopolysiloxane E3: [ka] Organopolysiloxane E4: [ka]

[0091] [Table 1]

[0092] Example 1: Preparation of a composition containing a polyorganosiloxane containing an acrylate group. The following substances are added to a 1-L reactor equipped with a mechanical stirrer, condenser, air inlet, and thermodynamic sheath while stirring: - 68.4g of acrylic acid - Chromium(III) acetylacetonate (Cr(acac)3) 0.332g -4-Methoxyphenol (MEHQ) 0.6g - Solvent (add as needed) (see Table 1) - 500 g of polydimethylsiloxane oil E1, E2, E3, or E4, functionalized with epoxy groups and having the kinematic viscosity at 25°C as defined above.

[0093] Adjust the stirring speed to 600 rpm and heat the reactor to 120°C using an aluminum hot plate while maintaining a reduced-pressure airflow of oil at approximately 4 L / h / kg. Samples are taken at various times, and the conversion rate of epoxy groups is measured using potentiometric assay. After the reaction time shown in the table below, the mixture is defolated under vacuum (gradually reduced to 20 mbar) while maintaining air bubbles to evaporate any unused acrylic acid and reaction solvent. After cooling, the resulting composition is pressure filtered through a cellulose filter to remove the acrylate functional groups. 1 The analysis is performed using 1H NMR.

[0094] The acrylication yield is calculated as the ratio of the measured number of moles of acrylic acid ester in the composition to the calculated theoretical number of moles of acrylic acid ester multiplied by 100. Therefore, the time for a 96% acrylication yield is the reaction time required to achieve such a yield, as shown in Table 2 below. 96 It is labeled as % acrylic.

[0095] The table below shows the comparative catalyst Cr(OAc)3 introduced at a concentration of 0.5 mol% relative to the epoxide concentration in comparative tests 3 and 4. In comparative tests 1 and 2, the concentration of the comparative catalyst is equal to 0.25 mol% relative to the epoxide concentration.

[0096] The acrylication selectivity (AS) is equal to the acrylication yield divided by the epoxy group conversion rate. The goal is to obtain the highest possible selectivity. The results are shown in the table below.

[0097] [Table 2]

[0098] *In comparative test 3, it was necessary to significantly alter the conditions to ensure catalyst solubility. Therefore, first, to ensure catalyst solubility, the catalyst content was reduced, and the premix containing acrylic acid, solvent, catalyst, and polymerization inhibitor had to be heated at 45°C for 2 hours. After adding one-third of the total weight of epoxy oil 2, the reaction medium had to be heated at 45°C to ensure homogeneity of the reaction medium. Next, the reaction medium was heated to 120°C, and the oil was poured in over 1 hour. The subsequent steps were the same as the process of the present invention.

[0099] **In comparative test 4, the conditions were adjusted as described above to ensure catalyst solubility and reaction medium homogeneity.**

[0100] The various tests described in the table above demonstrate that satisfactory yields and selectivity can be obtained using the method according to the present invention, even when using very different organopolysiloxane E. Furthermore, the operating conditions used in the tests of the present invention facilitate implementation on an industrial scale. This thus demonstrates the robustness and versatility of the process described according to the present invention.

[0101] In comparative tests using chromium acetate and n-butanol together, the acrylication selectivity was less than 95% (Comparative Test 1). Furthermore, as mentioned above in this application, the presence of n-butanol leads to the formation of products with an unpleasant odor.

[0102] Comparative tests using a chromium(III) acetate catalyst system without the addition of butanol (Comparative Test 2) are difficult to conduct with certain organopolysiloxane oils E. This is primarily due to the low solubility of the catalyst in these oils.

[0103] Therefore, the method according to the present invention makes it possible to obtain very good acrylic yields and selectivity using any kind of organopolysiloxane oil E under suitable conditions that are suitable for industrial scale.

[0104] Example 2: Applicability of the present invention process: The operating conditions in the aforementioned example were adapted for a 3-L reactor using organopolysiloxane oil E2.

[0105] The following table shows the implementation of the present invention process in three different ways.

[0106] [Table 3]

[0107] In Experiment 1, organopolysiloxane oil E2 was introduced into a reaction medium containing other components at a temperature of 60°C, and then the reactor was heated to 120°C under the same conditions as described above.

[0108] In Experiment 2, organopolysiloxane oil E2 was introduced into a reactor heated to 45°C, and then other components were added to the reactor and heated to 120°C under the same conditions as above.

[0109] In Test 3, the premix prepared the previous day is formed as follows: - Dissolve the catalyst Cr(acac)3 and the inhibitor 4-methoxyphenol (MeHQ) in acrylic acid at room temperature (21°C) for 5 minutes in the presence of MIBK solvent; - Introduce the mixture prepared above into the reactor at room temperature (21°C); - Add the entire amount of oil E2 and stir at room temperature for 10 minutes; - Stop stirring and allow the reaction medium to stand for 18 hours; Next, the reaction medium is heated to 120°C to carry out the acrylic reaction.

[0110] The excellent miscibility of the catalyst system used in this invention makes it possible to produce a homogeneous premix at room temperature that can be directly introduced into the reactor as a "one-pot" reaction to carry out the process of this invention. This flexibility eliminates the need for reactant injection, partial heating, or other obstacles to the industrialization of such processes, making it easier to implement such processes on an industrial scale.

Claims

1. A process for preparing a composition X comprising at least one organopolysiloxane A containing at least one (meth)acrylate group, the process comprising the following steps: a) At a temperature of 50°C to 130°C, preferably 70°C to 130°C, more preferably 90°C to 125°C, at least one organopolysiloxane E containing at least one epoxy group is reacted with acrylic acid or methacrylic acid or a mixture thereof in the presence of the following: - The catalyst C [CR(L) is a complex of chromium in the (III) oxidation state represented by the following formula (1) 1 ) 3 ] (1) In the formula, the symbol L 1 These may be the same or different, and represent a β-diketonate anion. - In the presence of a solvent S that is not an alcohol, and - Polymerization inhibitors of acrylic acid or methacrylic acid; b) Defoliate the reaction medium obtained at the end of step a); c) Obtain the composition X comprising at least one organopolysiloxane A.

2. The process according to claim 1, characterized in that, in step a), the molar ratio of the acrylic acid to the epoxy group of the organopolysiloxane E is greater than 1.05, preferably 1.05 to 15, and more preferably 1.05 to 10.

3. The process according to claim 1 or 2, characterized in that, in step a), the solvent S is selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, toluene, xylene, chlorobenzene, and mixtures thereof.

4. The process according to claim 3, characterized in that in step a), the content of the solvent S is 0 to 15% by weight, preferably 2 to 15% by weight, and more preferably 4 to 12% by weight, based on the total weight of the reaction medium used in step a) of the process.

5. The process according to any one of claims 1 to 4, characterized in that the catalyst C is a chromium complex represented by the following formula (1): [Cr(L 1 ) 3 ] (1) In the formula, the symbol L 1 These are identical or different ligands representing the β-diketonate anion shown in formula (2) below. 【Chemistry 1】 In the formula, R 1 and R 3 may be the same or different, and represent a hydrocarbon group of C 1 to C 30 , a hydrocarbon group of C 6 to C 30 containing an aromatic ring, or R 1 and R 3 together with the atoms to which they are attached form a monocyclic ring consisting of 6 to 10 carbon atoms. R 2 is hydrogen or C 1 ~C 30 It is a hydrocarbon group, or R 1 and R 2 It forms a monoring consisting of 5 to 10 atoms together with the atom to which it is bonded.

6. The process according to any one of claims 1 to 5, characterized in that the catalyst C is a β-diketate of chromium in the (III) oxidation state, selected from the group consisting of chromium(III) acetylacetonate, chromium(III) hexafluoroacetylacetonate, chromium(III) 2,2,6,6-tetramethyl-3,5-heptanedione, chromium(III) 3,5-heptanedione, and chromium(III) 2,2,7-trimethyl-3,5-octanedionate.

7. The process according to any one of claims 1 to 6, characterized in that the organopolysiloxane E comprises siloxyl units (I) and (II) of the following formula: 【Chemistry 2】 During the ceremony, a = 1 or 2, b = 0, 1, or 2, and a + b = 1, 2, or 3 c = 0, 1, 2, or 3 The symbol Y may be the same or different, and represents an organic group that includes an epoxy group and optionally includes one or more heteroatoms such as oxygen atoms. The organic group Y preferably has 2 to 20 carbon atoms, and more preferably Y is selected from the group consisting of alkyl glycidyl ethers, linear, branched or cyclic epoxyalkyls, linear, branched or cyclic epoxyalkenyls, and glycidyl carboxylates. - Symbol Z 1 and Z 2 The group may be the same or different, and represents a monovalent organic group having 1 to 30 carbon atoms, preferably selected from the group consisting of alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, and more preferably selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl, and phenyl groups, and the organopolysiloxane E contains at least two silicon atoms and at least one siloxyl unit (II) per molecule.

8. The process according to claim 7, characterized in that in the siloxyl unit (I), the symbol Y is selected from the group consisting of the organic groups (IV) to (VIII) of the following formula: 【Transformation 3】

9. The process according to any one of claims 1 to 8, characterized in that organopolysiloxane E contains 0.5% to 30% by weight, preferably 1% to 20% by weight, and more preferably 1% to 10% by weight of an organic group Y comprising an epoxy group, based on the total weight of organopolysiloxane E.

10. A composition X that can be obtained by the method described in any one of claims 1 to 9.

11. The process for manufacturing a coating on a substrate includes the following steps: a) Prepare composition X according to the method described in any one of claims 1 to 9; b) Prepare a radical crosslinkable silicone composition W containing the following components: - The above composition X, - Photoinitiator, and - At least one additive of optional choice; c) Apply the composition W to the substrate; and d) Crosslink the composition W by exposing it to radiation.

12. The process according to claim 11, wherein in step d), the radiation is ultraviolet light having a wavelength of less than 420 nm.

13. A substrate comprising at least one coating which can be obtained according to the method of claim 11 or 12.

14. The process for manufacturing elastomer products by additive manufacturing includes the following steps: a) Prepare silicone composition X according to the method described above; b) Irradiation source and photocrosslinkable silicone composition W containing the following 2 Use: i. The composition X, ii. Photoinitiator, and iii. At least one additive of optional choice; c) Photocrosslinkable silicone composition W using an irradiation source 2 Selectively irradiating at least a portion of it to form a portion of a silicone elastomer product; and d) Repeat step ii) a sufficient number of times to manufacture a silicone elastomer product.

15. The method according to claim 14, characterized in that the irradiation source is an LED lamp, preferably an LED lamp having a wavelength of 355, 365, 385, or 405 nm.

16. A silicone elastomer product that can be obtained by the method described in any one of claims 14 and 15.

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