Additive manufacturing method for producing silicone elastomer articles

Abstract

The present invention relates to an additive manufacturing process for producing a silicone elastomer article, said process comprising the steps of: i) using a photocrosslinkable silicone composition X comprising: a) at least one organopolysiloxane A comprising at least one (meth) acrylate group; b) at least one radical photoinitiator B as defined in the invention; ii) selectively irradiating at least a portion of the photo-crosslinkable silicone composition X by means of the irradiation source for forming a portion of the silicone elastomer article; and iii) repeating step ii) a number of times sufficient to produce the silicone elastomer article.

Description

Technical Field

[0001] The present invention relates to an additive manufacturing method for producing articles by 3D printing from a photocrosslinkable composition X comprising at least one organopolysiloxane and at least one type I photoinitiator. In particular, such a method enables the production of articles by 3D printing from a photocrosslinkable composition X comprising at least one organopolysiloxane (meth)acrylate and a photoinitiator as defined in the present invention. Background Art

[0002] Currently, the development of additive manufacturing is extremely active and has great growth potential due to its emergence and the numerous applications of the articles obtained therefrom.

[0003] The recently developed 3D technologies have improved printing resolution, relatively high printing speed, and flexibility in part modeling, while still maintaining low production costs.

[0004] A key element in the progress of this technical field is the development of new photoinitiators or new photoinitiator systems.

[0005] The design of these new photoinitiators enables the reduction of the time for additive manufacturing parts, and also enables operation at lower energies and the obtaining of more complex products by virtue of their properties.

[0006] In the field of free radical polymerization of acrylic organosilicon compositions, the commonly used photoinitiator molecules are so-called type I photoinitiators. Under irradiation, these molecules split and generate free radicals. These free radicals initiate the polymerization reaction that leads to the curing of the composition. Considerable efforts have been made to ensure that type I photoinitiators have the properties that enable them to be used in acrylic organosilicon formulations to obtain anti-stick coatings. Throughout this patent application, the term "type I photoinitiator" refers to a compound that can generate free radicals that initiate polymerization by intramolecular homolytic fragmentation under irradiation.

[0007] Type I photoinitiators are widely used, but they may have drawbacks. In particular, the solubility of these photoinitiators in organosilicon compositions is not always optimal. In addition, the photoinitiators and their degradation products (such as benzaldehyde) pose health risks and may have an unpleasant odor.

[0008] In particular, the toxicity of commonly used type I photoinitiators such as TPO-L (CAS 84434-11-7) may lead to its being prohibited from use in the food and health industries in the coming years.

[0009] In addition, in addition to being toxic to humans, TPO-L is also classified as ecotoxic by the European Chemicals Agency (ECHA).

[0010] In addition to these toxic properties, when there is at least 10% of a filler such as silica or other fillers with hydroxyl groups, the viscosity of TPO-L increases exponentially. This high viscosity makes the additive manufacturing method complex or even unimplementable.

[0011] The use of these fillers in high mass percentages can in particular confer improved and diverse mechanical properties to silicone articles, thus greatly expanding the scope of applications of articles obtained using additive manufacturing methods.

[0012] Therefore, it is crucial to develop type I photoinitiators that are compatible with such fillers.

[0013] Therefore, it is necessary to develop type I photoinitiators that can overcome these drawbacks. Summary of the Invention

[0014] In this context, the present invention aims to meet at least one of the following objectives.

[0015] One of the basic objectives of the present invention is to provide an additive manufacturing method comprising a photo-crosslinkable silicone composition having a type I photoinitiator, which has satisfactory or even improved properties at a low content of reactive substances.

[0016] Another basic objective of the present invention is to provide an additive manufacturing method comprising a photo-crosslinkable silicone composition having a type I photoinitiator, which does not have properties that are toxic to humans or the environment.

[0017] Another basic objective of the present invention is to provide an additive manufacturing method comprising a photo-crosslinkable silicone composition having a type I photoinitiator, which has satisfactory photochemical properties and is compatible with a filler content of more than 20% relative to the total mass of the composition.

[0018] Another basic objective of the present invention is to provide a compound that can be used as a free radical photoinitiator in an additive manufacturing method.

[0019] Another objective of the present invention is that this photo-crosslinkable silicone composition comprising a type I photoinitiator can be used to form an anti-stick coating.

[0020] Another objective of this patent application is to develop a type I photoinitiator that is suitable for additive manufacturing methods at low energy or even very low energy corresponding to wavelengths of 385 nm and 405 nm respectively.

[0021] Other objectives will become apparent upon reading the following description of the present invention.

[0022] Surprisingly, the present applicant has developed an additive manufacturing method in which the developed type I photoinitiator meets the above requirements. For this purpose, the photoinitiator of the present invention is prepared by a preparation method similar to the preparation methods disclosed in patent applications WO 2014 / 053455 or WO 2018 / 050901. Summary of the Invention

[0024] Accordingly, the present invention relates to an additive manufacturing method for producing organosilicon elastomeric articles, the method comprising the following steps:

[0025] i) using a photocrosslinkable organosilicon composition X and an irradiation source, the photocrosslinkable organosilicon composition X comprising:

[0026] a) at least one organopolysiloxane A containing at least one (meth)acrylate group

[0027] b) at least one radical photoinitiator B represented by formula (I):

[0028]

[0029] wherein,

[0030] R represents a linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene, the alkylene and heteroalkylene containing at least one siloxane functional group;

[0031] R1 represents a group of formula (II):

[0032]

[0033] wherein Ar represents an aryl group having 6-18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0034] - an alkyl group having 1-6 carbon atoms,

[0035] - an alkenyl group having 2-4 carbon atoms,

[0036] - a heteroatom O, N or S,

[0037] - a halogen,

[0038] - a SiMe3 group,

[0039] - a hydroxyl group (OH),

[0040] - an (O-Alk) group, where Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5;

[0041] R2 represents:

[0042] - a group R1,

[0043] - an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0044] - an alkyl group having 1 to 6 carbon atoms,

[0045] - an alkenyl group having 2 to 4 carbon atoms,

[0046] - a heteroatom O, N or S,

[0047] - a halogen,

[0048] - a SiMe3 group,

[0049] - a hydroxyl group (OH),

[0050] - a (O - Alk) group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5;

[0051] ii) selectively irradiating at least a part of the photocrosslinkable silicone composition X with the irradiation source for forming a part of the silicone elastomer article; and

[0052] iii) repeating step ii) a number of times sufficient to produce the silicone elastomer article.

[0053] The radical photoinitiator B defined according to the method of the present invention enables a photocrosslinkable silicone composition X with good performance in terms of conversion and reaction kinetics to be obtained.

[0054] This radical photoinitiator B has good solubility in silicone. Thus, the pure photoinitiator can be used by directly diluting it in the organopolysiloxane A.

[0055] Advantageously, the radical photoinitiator B can be dissolved in the organopolysiloxane A within less than 10 hours, or less than 5 hours, or less than 2 hours. For example, the solubility can be determined by adding 1 to 10 parts by mass of the radical photoinitiator B to 100 parts by mass of the organopolysiloxane A.

[0056] Furthermore, the use of the radical photoinitiator B according to the method of the present invention enables good crosslinking of the photocrosslinkable composition X and the transparency of the resulting silicone elastomer article after crosslinking.

[0057] It should be noted that the degradation products of the radical photoinitiator B defined in this patent application have satisfactory initial toxicological data.

[0058] In the present patent application, the term "organosilicon composition photopolymerizable by irradiation" refers to an organosilicon composition comprising at least one organopolysiloxane capable of being cured by electron or photon irradiation. Among electron irradiations, exposure to an electron beam can be mentioned. Among photon irradiations, exposure to radiation with a wavelength of 200 nm - 450 nm, in particular exposure to UV radiation, or exposure to gamma rays can be mentioned.

[0059] The term "(meth)acrylate" refers to a methacrylate group or an acrylate group.

[0060] The term "alkyl" refers to a linear or branched alkyl. This alkyl preferably contains 1 - 6 carbon atoms.

[0061] The term "alkylene" refers to a linear or branched divalent alkyl which may have an unsaturated bond. This alkylene preferably contains 1 - 50 carbon atoms, preferably 1 - 10 carbon atoms, more preferably 1 - 6 carbon atoms.

[0062] The term "heteroalkylene" refers to a linear or branched divalent heteroalkyl which may have an unsaturated bond. This heteroalkylene contains 1 - 50 carbon atoms, preferably 1 - 18 carbon atoms, and 1 - 6 heteroatoms selected from O, N, and S, where N and S may optionally be oxidized. These heteroatoms can be located at any position of the heteroalkyl, intersecting the chain or located at any position (within the chain or at the end).

[0063] Preferably, the "heteroalkylene" group as defined in the present invention contains at least one ester functional group in its carbon - based chain.

[0064] In the present patent application, "shear rate" or "shear velocity" is used to characterize the shear force within a fluid. Thus, a cone - plate viscometer enables the viscosity of a sample to be inferred proportionally according to the angular velocity of rotation in the sample (proportional to the shear rate). Unless otherwise specified, all viscosities considered in the present patent application correspond to viscosity values measured at 25 °C according to standard ASTM D4287. In the present patent application, unless otherwise specified, all percentages are expressed as mass percentages.

[0065] Detailed description of the present invention

[0066] Generally, all additive manufacturing processes have a common starting point, which is a computer data source or a computer program that can describe an object. This computer data source or this computer program can be based on an actual or virtual object.

[0067] For example, an actual object can be scanned using a 3D scanner, and the data obtained can be used to generate a computer data source or a computer program.

[0068] Alternatively, a computer data source or a computer program can be designed from scratch.

[0069] The computer data source or computer program is typically converted into a file in stereolithography (STL) format, but files in other formats can also be used. This file is typically read by 3D printing software, which uses the file and optionally user input information to divide the object into hundreds or thousands of "layers".

[0070] Typically, the 3D printing software transmits instructions to the machine, for example in the form of G-code, which are read by the 3D printer, which then typically manufactures the object layer by layer.

[0071] The additive manufacturing method via photopolymerization is an evolving technology. It starts with a photocrosslinkable liquid composition as the raw material, which is locally deposited on the surface and then crosslinked. Alternatively, the photocrosslinkable liquid composition is placed in a tank and then selectively crosslinked.

[0072] Various additive manufacturing method technologies are known to those skilled in the art, such as printing by laser stereolithography (SLA), by digital light processing (DLP), by continuous liquid interface production (CLIP), by ink deposition or by extrusion.

[0073] Advantageously, in the context of the present application, the additive manufacturing method is an additive manufacturing method by the following means: vat (en cuve) photopolymerization, in particular laser stereolithography (SLA) printing, digital light processing (DLP), or continuous liquid interface production (CLIP), or a method using radiation transmitted through a liquid crystal display (LCD).

[0074] These technologies and related equipment are well known to those skilled in the art, and those skilled in the art will be able to select the appropriate technology and the corresponding 3D printer.

[0075] These technologies and equipment are described, for example, in the following documents: WO 2015 / 197495, US 5236637, WO 2016 / 181149 and WO 2014 / 126837.

[0076] The irradiation source can be any irradiation source that allows the photocrosslinkable silicone composition X to be photocrosslinked.

[0077] Advantageously, the irradiation source is a light source, preferably an ultraviolet (UV), visible or infrared (IR) light source. Generally, a UV light source has a wavelength of 200 - 400 nm, a visible light source has a wavelength of 400 - 700 nm, and an IR light source has a wavelength greater than 700 nm, for example 700 nm - 1 mm or 700 - 10,000 nm.

[0078] The light source can be a gas discharge lamp, a diode such as a light emitting diode, or a laser.

[0079] Preferably, the irradiation source is selected from UV lamps, UV lasers, visible light lamps, visible light lasers, IR lamps, and IR lasers.

[0080] In a specific embodiment of the method, the irradiation source is a light emitting diode (LED) module, preferably an LED module having a wavelength of 355, 365, 385, or 405 nm.

[0081] The power of the irradiation source can be at least 1, 10, or 50 mW / cm 2 . It can be 1 - 1000 mW / cm 2 , preferably 1 - 500 mW / cm 2 , preferably 1 - 200 mW / cm 2 , and more preferably 1 - 50 mW / cm 2 .

[0082] In a specific embodiment, the irradiation penetration depth (Dp) is less than 2000 μm for an irradiance of 1 - 50 mW / cm at 385 or 405 nm. Preferably, the penetration depth is 100 - 1000 μm, and more preferably 100 - 500 μm. 2 Those skilled in the art will be able to adjust the photoinitiator content, the power of the irradiation source, and the irradiation duration to obtain the desired penetration depth suitable for the object.

[0083] In a preferred embodiment, the method does not use a dual - cure type composition. In particular, the method does not use a composition that can cross - link by polyaddition.

[0084] In one embodiment, the method includes a cleaning step such as solvent rinsing or a post - treatment step such as exposure to an additional radiation source or exposure to heat for a given duration.

[0085] In a specific embodiment, the method does not include a post - treatment step.

[0086] Preferably, the photocrosslinkable silicone composition X is used in a cuve, and the silicone elastomer article is produced on a plate (preferably a moving plate). The plate can be any type of plate.

[0087] Advantageously, the plate is the platform of a 3D printer, such as a moving platform, or a support for one or more layers of the photocrosslinkable silicone composition X that is initially printed in the desired geometry to be able to be separated and cross - linked under irradiation.

[0088] Advantageously, the plate is the platform of a 3D printer, such as a moving platform, or a support for one or more layers of the photocrosslinkable silicone composition X that is initially printed in the desired geometry to be able to be separated and cross - linked under irradiation.

[0089] According to a first embodiment of the method, the additive manufacturing method is carried out layer by layer, each layer representing a surface of the photocrosslinkable silicone composition X.

[0090] This first embodiment is particularly suitable for printing by stereolithography (SLA) and digital light processing (DLP).

[0091] In this first embodiment, the irradiation step ii) may include the following sub-steps:

[0092] a. depositing a first layer of the photocrosslinkable silicone composition X on a plate;

[0093] b. selectively irradiating the surface of the photocrosslinkable silicone composition X with an irradiation source to form a crosslinked layer of the silicone elastomer article to be produced;

[0094] c. forming an additional layer of the photocrosslinkable silicone composition X on the first crosslinked layer produced in step b); and

[0095] d. selectively irradiating the additional layer to form an additional crosslinked layer of the silicone elastomer article to be produced.

[0096] The plate on which the layer of the photocrosslinkable silicone composition X is deposited during step a) can be any type of plate.

[0097] Preferably, the plate is a movable plate.

[0098] Advantageously, the plate is a platform of a 3D printer, such as a movable platform. The support applied to the plate may also contain the first layer or generally contain a plurality of layers of the photocrosslinkable silicone composition X deposited and selectively irradiated.

[0099] Preferably, during step d), the additional layer formed adheres to the first crosslinked layer of the silicone elastomer article formed in step b).

[0100] Advantageously, the thickness of the layer of the photocrosslinkable silicone composition X is 0.1 - 500 μm, preferably 5 - 400 μm, preferably 10 - 300 μm, and more preferably 10 - 100 μm.

[0101] In a specific embodiment, the irradiation duration of the layer of the photocrosslinkable silicone composition X is at least 0.001 seconds.

[0102] Preferably, the irradiation duration is from 0.001 seconds to 10 minutes, preferably from 0.001 seconds to 5 minutes, and more preferably from 0.01 seconds to 1 minute.

[0103] These different parameters can be adjusted according to the desired results.

[0104] Deposition of the layer of the photocrosslinkable organosilicon composition X can be carried out by moving the support or using a blade or a doctor blade which deposits a new layer of the photocrosslinkable organosilicon composition X.

[0105] Preferably, in the case where the irradiation source is a laser (e.g., SLA method), the laser tracks the surface of the layer of the organosilicon elastomeric article to be produced for selective irradiation, and in the case where the irradiation source is a light-emitting diode module (e.g., DLP method), a single image of the crosslinked layer of the object to be printed is projected onto the entire surface of the photocrosslinkable composition X.

[0106] In this first embodiment, two variants are possible: additive manufacturing can be carried out by top irradiation and bottom irradiation. These two variants are described in document US5236637.

[0107] In the first variant of this first embodiment, additive manufacturing is carried out from the top: the photocrosslinkable organosilicon composition X is accommodated in a trough, and the irradiation source is focused on the surface of the photocrosslinkable organosilicon composition X. The irradiated layer is the layer between the plate and the surface of the photocrosslinkable organosilicon composition X.

[0108] In this first variant, deposition of the layer of the photocrosslinkable organosilicon composition X is carried out by lowering the plate into the trough by a distance equal to the layer thickness. Then the surface of the photocrosslinkable organosilicon composition X can be swept with a blade or a doctor blade to flatten it.

[0109] In the second variant of this first embodiment, additive manufacturing is carried out from the bottom: the trough includes a transparent bottom and a non-sticky surface, and the irradiation source is focused on the transparent bottom of the trough. The irradiated layer is thus the layer between the bottom of the trough and the plate.

[0110] In this case, deposition of the layer of the photocrosslinkable organosilicon composition X is carried out by raising the plate to allow the photocrosslinkable organosilicon composition X to be inserted between the bottom of the trough and the plate. The distance between the bottom of the trough and the plate corresponds to the layer thickness.

[0111] Advantageously, the additive manufacturing method is an additive manufacturing method by digital light processing (DLP) by vat photopolymerization, wherein additive manufacturing is carried out from the bottom: deposition of the layer of the photocrosslinkable organosilicon composition X is carried out by raising the plate in the trough to allow the photocrosslinkable organosilicon composition X to be inserted between the bottom of the trough and the plate. The distance between the bottom of the trough and the plate corresponds to the layer thickness.

[0112] According to the second embodiment, the additive manufacturing method is carried out continuously. This second embodiment is particularly applicable to continuous liquid interface production (CLIP) as described in document WO2014 / 126837. In this second embodiment, the irradiation step ii) may include the following sub-steps, which occur simultaneously:

[0113] a. Selectively irradiating at least a part of the photocrosslinkable silicone composition X with an irradiation source to form a part of the silicone elastomer article on the plate; and

[0114] b. Moving the plate and the part of the silicone elastomer article formed in step a) away from the irradiation source along the irradiation axis.

[0115] Advantageously, in step a), a part of the silicone elastomer article is formed on the plate, and during step b), it is the plate that is moving simultaneously.

[0116] Preferably, in this second embodiment, the additive manufacturing is carried out by irradiating from the bottom: the trough includes a transparent bottom, and the irradiation source is focused on the transparent bottom of the trough.

[0117] Due to the oxygen-permeable membrane, photopolymerization occurs only at the interface between the photocrosslinkable silicone composition X and the plate; the photocrosslinkable composition X between the bottom of the trough and the interface does not undergo photopolymerization.

[0118] Thus, a continuous liquid interface can be maintained, where the silicone elastomer article is formed by irradiating the photocrosslinkable composition X and simultaneously moving the part of the silicone elastomer article formed on the plate out of the trough.

[0119] Once the silicone elastomer article is obtained, rinsing can be carried out to remove the uncrosslinked photocrosslinkable silicone composition X.

[0120] Once the silicone elastomer article is obtained, additional steps can also be carried out to improve the surface quality of the article. The use and application of coatings such as surface coatings in the final layer make it possible to improve the surface quality of the article in particular.

[0121] Spraying or coating the silicone elastomer article with an LSR or RTV silicone composition that can be crosslinked by heating or UV radiation can also be used to have a smooth appearance. The obtained article can also be surface-treated with a laser.

[0122] For medical applications, the obtained silicone elastomer article can be sterilized. The sterilization of the article can be carried out by heating in a dry atmosphere or in an autoclave with steam, for example, at a temperature above 100 °C. Sterilization can also be carried out by gamma rays, using ethylene oxide, or by electron beam.

[0123] The present invention also relates to silicone elastomer articles obtained by the methods described in the present application.

[0124] The obtained silicone elastomer articles can be any articles with simple or complex geometries. For example, they can be silicone molds, masks, tubes, anatomical models (functional or non-functional), such as hearts, kidneys, prostates, models for surgeons or teaching, orthotics, prostheses, such as dentures, dental aligners, mouth protectors, or different types of implants, such as long-term implants, hearing aids, stents, laryngeal implants, etc.

[0125] The obtained silicone elastomer articles can also be jacks (vérin) for robots, seals (joint), mechanical parts for automobiles or aviation, parts for electronic devices, parts for encapsulating components, vibration isolators (isolant), shock isolators or sound isolators.

[0126] Photocrosslinkable composition X:

[0127] According to one embodiment, the photocrosslinkable silicone composition X has a dynamic viscosity of 0.01 - 20 Pa·s at a shear rate of 10 s -1 and preferably has a dynamic viscosity of 0.1 - 10 Pa·s, more preferably 0.1 - 5 Pa·s at a shear rate of 10 s -1 .

[0128] In the present patent application, according to the method of the present invention, the photocrosslinkable silicone composition X comprises at least one organopolysiloxane A.

[0129] Preferably, according to the method of the present invention, the photocrosslinkable silicone composition X comprises at least one organopolysiloxane A which contains at least one (meth)acrylate group, preferably at least two (meth)acrylate groups.

[0130] As representatives of the (meth)acrylate functional groups carried by silicone and particularly suitable for the present invention, mention may be made more particularly of acrylate derivatives, methacrylates, (meth)acrylate ethers and (meth)acrylate esters linked to the polysiloxane chain by Si - C bonds.

[0131] According to one embodiment, the organopolysiloxane A comprises:

[0132] a) at least one unit of the following formula (III):

[0133] R a Z b SiO (4-a-b) / 2 (III)

[0134] In the formula:

[0135] - The symbol R, which may be the same or different, each represents a linear or branched C1-C 18 alkyl group, a C6-C 12 aryl or aralkyl group, wherein the alkyl and aryl groups may optionally be substituted, preferably substituted by a halogen atom, or is the group -OR 5 , where R 5 is a hydrogen atom or a hydrocarbon group containing 1-10 carbon atoms,

[0136] - The symbol Z is a monovalent group of the formula -y-(Y’)n, where:

[0137] - y represents a polyvalent alkylene or heteroalkylene group having 1 to C 18 The alkylene and heteroalkylene groups may be linear or branched, and may optionally be interrupted by one or more cycloalkylene groups, and optionally extended by a C1-C4 divalent oxyalkylene or polyoxyalkylene group, and the alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups may optionally be substituted by one or more hydroxyl groups,

[0138] - Y’ represents a monovalent alkenylcarbonyloxy group, and

[0139] - n is equal to 1, 2 or 3, and

[0140] - a is an integer equal to 0, 1 or 2, b is an integer equal to 1 or 2 and the sum of a + b = 1, 2 or 3; and

[0141] b) Optionally, a unit of the following formula (IV):

[0142] R a SiO (4-a) / 2 (IV)

[0143] In the formula:

[0144] - The symbol R is as defined above in formula (III), and

[0145] - a is an integer equal to 0, 1, 2 or 3.

[0146] In the above formulas (III) and (IV), the symbol R, which may be the same or different, each represents a linear or branched C1-C 18 alkyl group or a C6-C 12 aryl or aralkyl group. Preferably, the symbol R represents a monovalent group selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, dimethylphenyl, tolyl and phenyl, and preferably, the symbol R represents methyl.

[0147] The organopolysiloxane A may have a linear, branched, cyclic or network structure. Preferably, the organopolysiloxane A has a linear structure. When it comes to linear organopolysiloxanes, they may be substantially composed of the following units:

[0148] -Siloxane units 《D》, selected from the units of the formula R2SiO 2 / 2 、RZSiO 2 / 2 and Z2SiO 2 / 2 ;

[0149] -Siloxane units 《M》, selected from the units of the formula R3SiO 1 / 2 、R2ZSiO 1 / 2 、RZ2SiO 1 / 2 and Z3SiO 1 / 2 units, and

[0150] -The symbols R and Z are as defined above in formula (III).

[0151] According to one embodiment, in the above formula (III), among the alkenylcarbonyloxy groups Y' mentioned above, acryloyloxy [CH2=CH-CO-O-] and methacryloyloxy: [CH2=C(CH3)-CO-O-] can be mentioned. Advantageously, the organopolysiloxane A contains at least 2 alkenylcarbonyloxy groups Y', preferably at least 3 alkenylcarbonyloxy groups Y'.

[0152] As an illustration of the symbol y in the units of formula (III), the following groups can be mentioned:

[0153] -CH2-;

[0154] -(CH2)2-;

[0155] -(CH2)3-;

[0156] -CH2-CH(CH3)-CH2-;

[0157] -(CH2)3-NR'-CH2-CH2-; where R' is a C1-C6 alkyl group

[0158] -(CH2)3-OCH2-;

[0159] -(CH2)3-[O-CH2-CH(CH3)-] n -; where n = 1 to 25

[0160] -(CH2)3-O-CH 2- CH(OH)(-CH2-);

[0161] -(CH2)3-O-CH2-C(CH2-CH3)[-(CH2-)]2;

[0162] -(CH2)3-O-CH2-C[-(CH2)-]3, and

[0163] -(CH2)2-C6H9(OH)-.

[0164] Preferably, the organopolysiloxane A corresponds to the following formula (V):

[0165]

[0166] In the formula:

[0167] - The symbol R 1 , which are the same or different, each represents a linear or branched C1-C 18 alkyl group, a C6-C 12 aryl or aralkyl group, and the alkyl and aryl groups may be optionally substituted, preferably substituted by a halogen atom, or is the group -OR 5 , where R 5 is a hydrogen atom or a hydrocarbon group containing 1-10 carbon atoms,

[0168] - The symbol R 2 and R 3 , which are the same or different, each represents R 1 or a monovalent group of the formula Z = -y-(Y')n, where:

[0169] -y represents a polyvalent alkylene or heteroalkylene group of C1-C 18 which may be linear or branched, and may be optionally interrupted by one or more cycloalkylene groups, and optionally extended by a C1-C4 divalent oxyalkylene or polyoxyalkylene group, and the alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups may be optionally substituted by one or more hydroxyl groups,

[0170] -Y' represents a monovalent alkenylcarbonyloxy group

[0171] -n is equal to 1, 2 or 3, and

[0172] - where a = 0-1000, b = 0-500, c = 0-500, d = 0-500 and a + b + c + d = 0-2500, preferably a = 0-500 and a + b + c + d = 0-500,

[0173] - provided that at least one symbol R 2 or R 3 represents a monovalent group of the formula Z, preferably, at least two symbols R 2 or R 3 represent a monovalent group of the formula Z.

[0174] According to a preferred embodiment, in the above formula (V):

[0175] - c = 0, d = 0, a = 1 - 1000, b = 1 - 250, the symbol R 2 represents a monovalent group of formula Z, and the symbol R 1 and R 3 have the same meaning as defined above.

[0176] Even more preferably, in the above formula (V):

[0177] - c = 0, d = 0, a = 1 - 500, b = 2 - 100, the symbol R 2 represents a monovalent group of formula Z, and the symbol R 1 and R 3 have the same meaning as defined above.

[0178] According to one embodiment, the organopolysiloxane A according to the present invention corresponds to one of the following formulas (VIa), (VIb), (VIc) or (VId):

[0179]

[0180]

[0181] wherein:

[0182] R, which may be the same or different, represents a hydrogen atom or a hydroxyl group;

[0183] - x1 is an integer from 1 to 1000; preferably x1 is from 1 to 500;

[0184] - n1 is an integer from 1 to 100, preferably n1 is from 2 to 50;

[0185] - x2 is an integer from 1 to 1000; preferably x2 is from 1 to 500;

[0186] - n2 is an integer from 0 to 100, preferably n2 is from 0 to 50;

[0187] - x3 is an integer from 1 to 1000; preferably x3 is from 1 to 500;

[0188] - n3 is an integer from 0 to 100, preferably n3 is from 0 to 50;

[0189] - x4 is an integer from 1 to 1000; preferably x4 is from 1 to 500;

[0190] - n4 is an integer from 0 to 100, preferably n4 is from 0 to 50;

[0191] - m1, m2, m3 and m4 are integers from 1 to 8.

[0192] According to one embodiment, the organopolysiloxane A according to the present invention corresponds to one of the following formulas (VIIa), (VIIb), (VIIc) or (VIId):

[0193]

[0194]

[0195] wherein:

[0196] - x1 is an integer from 1 to 1000; preferably x1 is from 1 to 500;

[0197] - n1 is an integer from 0 to 100, preferably n1 is from 0 to 50;

[0198] - x2 is an integer from 1 to 1000; preferably x2 is from 1 to 500;

[0199] - n2 is an integer from 0 to 100, preferably n2 is from 0 to 50;

[0200] - x3 is an integer from 1 to 1000; preferably x3 is from 1 to 500;

[0201] - n3 is an integer from 1 to 100, preferably n3 is from 1 to 50;

[0202] - x4 is an integer from 1 to 500; preferably x4 is from 1 to 200;

[0203] - n4 is an integer from 0 to 100, preferably n4 is from 0 to 50.

[0204] According to the method of the present invention, the photocrosslinkable organosilicon composition X may contain 10 - 99.9% by mass of the organopolysiloxane A, based on the total mass of the photocrosslinkable organosilicon composition X.

[0205] Preferably, the photocrosslinkable organosilicon composition X may contain 10 - 99.5% by mass of the organopolysiloxane A, based on the total mass of the photocrosslinkable organosilicon composition X.

[0206] Of course, according to a variant, the organopolysiloxane A may be a mixture of compounds that meet the definition of the organopolysiloxane A.

[0207] For the purposes of the present invention, the free radical photoinitiator B is represented by the formula (I):

[0208]

[0209] wherein,

[0210] R represents linear or branched C1 - C 50An alkylene or heteroalkylene group, preferably linear or branched C1-C 18 An alkylene or heteroalkylene group, said alkylene and heteroalkylene groups containing at least one siloxane functional group;

[0211] R1 represents a group of formula (II):

[0212]

[0213] wherein Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0214] - An alkyl group having 1 to 6 carbon atoms,

[0215] - An alkenyl group having 2 to 4 carbon atoms,

[0216] - A heteroatom O, N or S,

[0217] - A halogen,

[0218] - A SiMe3 group,

[0219] - A hydroxyl group (OH),

[0220] - A (O-Alk) group, wherein Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5;

[0221] R2 represents:

[0222] - A group R1,

[0223] - An aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0224] - An alkyl group having 1 to 6 carbon atoms,

[0225] - An alkenyl group having 2 to 4 carbon atoms,

[0226] - A heteroatom O, N or S,

[0227] - A halogen,

[0228] - A SiMe3 group,

[0229] - A hydroxyl group (OH),

[0230] - A (O-Alk) group, wherein Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5.

[0231] According to an embodiment of the method of the present invention, the free radical photoinitiator B is a compound of formula (VIII):

[0232]

[0233] Wherein:

[0234] R1 and R2 represent the groups as defined above;

[0235] R3 represents a linear or branched C1-C6 alkylene or heteroalkylene group;

[0236] R4 represents a linear or branched C1-C 50 alkylene or heteroalkylene group, preferably a linear or branched C1-C 18 alkylene or heteroalkylene group, and said R4 contains at least one siloxane functional group.

[0237] Preferably, the free radical photoinitiator B is a compound of formula (VIIIa):

[0238]

[0239] Wherein, R3 and R4 represent the groups as defined above.

[0240] Alternatively, the free radical photoinitiator B is a compound of formula (VIIIb):

[0241]

[0242] Wherein, R3 and R4 represent the groups as defined above.

[0243] According to an embodiment of the present invention, the free radical photoinitiator B is the following organopolysiloxane, and this organopolysiloxane contains:

[0244] a) at least one unit R c Z d SiO (4-c-d) / 2 (IX)

[0245] In formula (IX):

[0246] - The symbol R, being the same or different, each represents a linear or branched C1-C 18 alkyl group, C6-C 12 aryl or aralkyl group, and said alkyl and aryl groups may be optionally substituted, preferably substituted by a halogen atom, or is the group -OR 5 wherein R 5 is a hydrogen atom or a hydrocarbon group containing 1-10 carbon atoms,

[0247] - The symbol Z is a monovalent group of formula -y-(Y’)n, wherein:

[0248] -y represents C1-C 50 , preferably C1-C 18 a polyvalent alkylene or heteroalkylene group, said alkylene and heteroalkylene groups may be linear or branched and may optionally be interrupted by one or more heteroatoms selected from O, N and S, where N and S may optionally be oxidized; these alkylene or heteroalkylene groups may optionally be substituted by one or more hydroxy groups,

[0249] -Y’ represents a group of formula (X):

[0250]

[0251] wherein:

[0252] R1 represents a group of formula (XI):

[0253]

[0254] wherein Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0255] - an alkyl group having 1 to 6 carbon atoms,

[0256] - an alkenyl group having 2 to 4 carbon atoms,

[0257] - a heteroatom O, N or S,

[0258] - a halogen,

[0259] - a SiMe3 group,

[0260] - a hydroxy group (OH),

[0261] - a group (O-Alk), where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5;

[0262] R2 represents:

[0263] - a group R1,

[0264] - an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0265] - an alkyl group having 1 to 6 carbon atoms,

[0266] - an alkenyl group having 2 to 4 carbon atoms,

[0267] - a heteroatom O, N or S,

[0268] - a halogen,

[0269] -SiMe3 group

[0270] -hydroxy group (OH)

[0271] -(O-Alk) group, where Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5

[0272] -n is equal to 1 or 2

[0273] -c is an integer equal to 0, 1 or 2, d is an integer equal to 1 or 2 and the sum of c + d = 1, 2 or 3; and

[0274] b) unit MDT of the following formula (XII):

[0275] R c SiO (4-c) / 2 (XII)

[0276] In the formula:

[0277] -The symbol R is defined as above in formula (IX), and

[0278] -c is an integer equal to 0, 1, 2 or 3

[0279] In the above formulas (IX) and (XII), the symbol R is the same or different, each representing a linear or branched C1-C 18 alkyl group or a C6-C 12 aryl or aralkyl group. Preferably, the symbol R represents a monovalent group selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, dimethylphenyl, tolyl and phenyl, and preferably, the symbol R represents methyl

[0280] The free radical photoinitiator B of the present invention can have a linear, branched, cyclic or network structure. Preferably, the free radical photoinitiator B has a linear structure. When it comes to linear organopolysiloxanes, it can be substantially composed of the following units:

[0281] -Siloxane unit 《D》, selected from units of the formula R2SiO 2 / 2 、RZSiO 2 / 2 and Z2SiO 2 / 2 units;

[0282] -Siloxane unit 《M》, selected from units of the formula R3SiO 1 / 2 、R2ZSiO 1 / 2 、RZ2SiO 1 / 2 and Z3SiO 1 / 2 units, and

[0283] - The symbols R and Z are as defined above in formula (IX).

[0284] In the present invention:

[0285] - The siloxy unit 《M》 represents a siloxy unit of the formula Y3SiO 1 / 2 .

[0286] - The siloxy unit 《D》 represents a siloxy unit of the formula Y2SiO 2 / 2 .

[0287] - The siloxy unit 《T》 represents a siloxy unit of the formula YSiO 3 / 2 .

[0288] - The siloxy unit 《Q》 represents a siloxy unit of the formula SiO 4 / 2 .

[0289] The symbol Y is the same or different groups R.

[0290] The free radical photoinitiator B as defined in formulas (IX) and (XII) may optionally contain units T and Q.

[0291] According to one embodiment of the method of the present invention, the free radical photoinitiator B is a compound of formula (XIII):

[0292]

[0293] wherein,

[0294] R5, which are the same or different, represent:

[0295] - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl,

[0296] - an aryl group containing 6 - 10 carbon atoms, preferably phenyl,

[0297] - an alkenyl group containing 2 - 6 carbon atoms, preferably vinyl,

[0298] - an acrylate or methacrylate group,

[0299] - hydroxy (OH),

[0300] - a (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5,

[0301] -(O - Alk) xa group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, and x represents an integer from 2 - 200,

[0302] - a linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, such as (C1 - C5)alkyl - CF3, and the alkyl group is linear or branched,

[0303] - hydrogen,

[0304] - a group of formula (XIV):

[0305]

[0306] wherein R1 and R2 represent the groups defined as above,

[0307] R6 represents a linear or branched C1 - C 50 alkylene or heteroalkylene group, preferably a linear or branched C1 - C 18 alkylene or heteroalkylene group;

[0308] a represents an integer from 0 - 100;

[0309] The method is characterized in that at least one group R5 is represented by a group of formula (XIV).

[0310] Preferably, the free radical photoinitiator B is characterized in that the group of formula (XIV) is represented by a compound of formula (XIIIa):

[0311]

[0312] wherein, R6 is defined as above.

[0313] Alternatively, the free radical photoinitiator B is characterized in that the group of formula (XIV) is represented by a compound of formula (XIIIb):

[0314]

[0315] wherein, R6 is defined as above.

[0316] According to one embodiment of the method of the present invention, the free radical photoinitiator B is a compound of formula (XV):

[0317]

[0318] R7, which may be the same or different, represents:

[0319] - An alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0320] - An aryl group having 6 to 10 carbon atoms, preferably phenyl,

[0321] - An alkenyl group having 2 to 6 carbon atoms, preferably vinyl,

[0322] - Hydroxy (OH),

[0323] - (O - Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0324] - (O - Alk) x group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0325] - An acrylate or methacrylate group,

[0326] - A linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, and the alkyl is linear or branched,

[0327] - Hydrogen,

[0328] R8 represents a group defined for R7 or a group of formula (XVI):

[0329]

[0330] where R1 and R2 represent the groups defined above,

[0331] R6 represents a linear or branched C1 - C 50 alkylene or heteroalkylene, preferably linear or branched C1 - C 18 alkylene or heteroalkylene;

[0332] a represents an integer from 0 to 10;

[0333] b represents an integer from 1 to 100;

[0334] The method is characterized in that at least one group R8 is represented by a group of formula (XVI).

[0335] Preferably, the group of formula (XVI) defined above has the following formula:

[0336]

[0337] wherein R6 is as defined above.

[0338] Alternatively, the group of formula (XVI) as defined above has the following formula:

[0339]

[0340] wherein R6 is as defined above.

[0341] In a specific embodiment of the present invention, the radical photoinitiator B is a compound of formula (XV) as defined above, wherein two successive siloxane units may be interrupted by the unit O—Si(CH3)2—CH2—CH2—Si(CH3)2.

[0342] In one embodiment, the method of the present invention is characterized in that the radical photoinitiator B is a compound of formula (XVII):

[0343]

[0344] wherein,

[0345] R9, which are the same or different, represent:

[0346] - an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0347] - an aryl group containing 6 to 10 carbon atoms, preferably phenyl,

[0348] - an alkenyl group containing 2 to 6 carbon atoms, preferably vinyl,

[0349] - hydroxy (OH),

[0350] - a (O—Alk) group, wherein Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0351] - a (O—Alk) x group, wherein Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0352] - an acrylate or methacrylate group,

[0353] - a linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, such as (C1 - C5) alkyl - CF3, and the alkyl group is linear or branched,

[0354] - an amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group containing 1 - 5 carbon atoms,

[0355] - a carbonyl or carboxyl group,

[0356] - hydrogen,

[0357] - a group of formula (XVIII):

[0358]

[0359] wherein R1 and R2 represent the groups defined as above,

[0360] R6 represents a linear or branched C1 - C 50 alkylene or heteroalkylene group, preferably a linear or branched C1 - C 18 alkylene or heteroalkylene group;

[0361] R 10 , which are the same or different, represent:

[0362] - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl,

[0363] - an aryl group containing 6 - 10 carbon atoms, preferably phenyl,

[0364] - an alkenyl group containing 2 - 6 carbon atoms, preferably vinyl,

[0365] - hydroxyl (OH),

[0366] - (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5,

[0367] - (O - Alk) x group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0368] - an acrylate or methacrylate group,

[0369] - a linear or branched alkyl group containing 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, such as (C1-C5) alkyl-CF3, and the alkyl group is linear or branched,

[0370] - an amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group containing 1 to 5 carbon atoms,

[0371] - a carbonyl or carboxyl group,

[0372] - hydrogen,

[0373] R 11 represents the group -CH3 or an oxygen atom;

[0374] Z represents the group -CH2- or an oxygen atom;

[0375] Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0376] - an alkyl group having 1 to 6 carbon atoms,

[0377] - an alkenyl group having 2 to 4 carbon atoms,

[0378] - a heteroatom O, N or S,

[0379] - a halogen,

[0380] - a SiMe3 group,

[0381] - a hydroxyl group (OH),

[0382] - a (O-Alk) group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5;

[0383] m represents a natural integer from 1 to 8;

[0384] p represents a natural integer equal to 0 or 1;

[0385] q represents a natural integer from 0 to 100;

[0386] a represents a natural integer equal to 1 or 2;

[0387] b represents a natural integer from 0 to 100.

[0388] According to one embodiment, the method of the present invention is characterized in that the radical photoinitiator B is a compound of formula (XVII) as indicated above:

[0389] wherein, R9 and R10 , identical or different, represent:

[0390] - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0391] - hydroxyl (OH),

[0392] - a hydrogen atom

[0393] R 11 represents the group -CH3 or an oxygen atom;

[0394] Z represents the group -CH2- or an oxygen atom;

[0395] Ar represents an aryl group having 6 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0396] - an alkyl group having 1 to 6 carbon atoms,

[0397] - an alkenyl group having 2 to 4 carbon atoms,

[0398] - a heteroatom O, N or S,

[0399] - a halogen,

[0400] - the SiMe3 group,

[0401] - hydroxyl (OH),

[0402] m represents a natural integer from 1 to 8;

[0403] p represents a natural integer equal to 0 or 1;

[0404] q represents a natural integer from 0 to 10;

[0405] a represents a natural integer equal to 1 or 2;

[0406] b represents a natural integer from 0 to 20.

[0407] In one embodiment, the method of the present invention is characterized in that the radical photoinitiator B is a compound of formula (XIX):

[0408]

[0409] 10 , identical or different, represent:

[0410] - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0411] - an aryl group having 6 to 10 carbon atoms, preferably phenyl,

[0412] - An alkenyl group having 2 to 6 carbon atoms, preferably a vinyl group,

[0413] - Hydroxy (OH),

[0414] - (O - Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0415] - (O - Alk) x group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0416] - An acrylate or methacrylate group,

[0417] - A linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, such as (C1 - C5) alkyl - CF3, and the alkyl is linear or branched,

[0418] - An amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group having 1 to 5 carbon atoms,

[0419] - Carbonyl or carboxyl,

[0420] - Hydrogen,

[0421] R 11 represents the group - CH3 or an oxygen atom;

[0422] Z represents the group - CH2 - or an oxygen atom;

[0423] Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0424] - An alkyl group having 1 to 6 carbon atoms,

[0425] - An alkenyl group having 2 to 4 carbon atoms,

[0426] - A heteroatom O, N or S,

[0427] - A halogen,

[0428] - SiMe3 group,

[0429] - Hydroxy (OH),

[0430] -(O-Alk) group, where Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5;

[0431] m represents a natural integer from 1 to 8;

[0432] p represents a natural integer equal to 0 or 1;

[0433] q represents a natural integer from 0 to 100;

[0434] a represents a natural integer equal to 1 or 2;

[0435] b represents a natural integer from 0 to 100;

[0436] The method is characterized in that when a = 1:

[0437] q > 0 or at least one group R9 is a hydroxyl group.

[0438] According to one embodiment, the method of the present invention is characterized in that the radical photoinitiator B is a compound of formula (XIX) as indicated above:

[0439] wherein, R9 and R 10 , which are the same or different, represent:

[0440] - an alkyl group containing 1-15 carbon atoms, preferably 1-5 carbon atoms, preferably methyl,

[0441] - hydroxyl (OH),

[0442] - a hydrogen atom

[0443] R 11 represents the group -CH3 or an oxygen atom;

[0444] Z represents the group -CH2- or an oxygen atom;

[0445] Ar represents an aryl group of 6 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0446] - an alkyl group of 1-6 carbon atoms,

[0447] - an alkenyl group of 2-4 carbon atoms,

[0448] - a heteroatom O, N or S,

[0449] - a halogen,

[0450] - the SiMe3 group,

[0451] - hydroxyl (OH),

[0452] m represents a natural integer from 1 to 8;

[0453] p represents a natural integer equal to 0 or 1;

[0454] q represents a natural integer from 0 to 10;

[0455] a represents a natural integer equal to 1 or 2;

[0456] b represents a natural integer from 0 to 20;

[0457] The method is characterized in that when a = 1:

[0458] q > 0 or at least one group R9 is a hydroxyl group.

[0459] In one embodiment, the method of the present invention is characterized in that the photocrosslinkable composition X further comprises a photoinitiator selected from type I radical photoinitiators or type II radical photoinitiators.

[0460] Therefore, the photocrosslinkable composition X may further comprise a photoinitiator selected from the following: type I radical photoinitiators such as:

[0461] acylphosphine oxides, bis-acylphosphine oxides and their derivatives, such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate (TPO-L), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), benzoin ethers, benzoyl oxime, acetophenone & hydroxyacetophenone (HAP), phenylglyoxal, α-hydroxy ketones, α-amino ketones and CPO-1 & CPO-2:

[0462]

[0463] As examples of commercial products of such photoinitiators, mention may be made in particular of:

[0464] bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide sold by IGM Resin B.V. under the name Omnirad TM 819; a liquid mixture of acylphosphine oxide and at least one other photoinitiator sold by IGM Resin B.V. under the name Omnirad TM 1000, Omnirad TM 2022, Omnirad TM 2100 or Omnirad TM 4265; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl),2-hydroxy-2-methylpropiophenone, sold by IGM Resin B.V. under the name Omnirad TMThe name of 1173 for sale; 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)-1-butanone, sold by IGM Resin B.V. under the name Omnirad TM The name of 369 for sale, or by under the name of (for sale); 2,2-dimethoxy-1,2-diphenylethane-1-one, by under the name of for sale; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, sold by IGM Resin B.V. under the name Omnirad TM The name of 907 for sale, or by under the name of (for sale); 2-hydroxy-2-methyl-1-phenyl-1-propanone, by under the name of The name of 1173 for sale; 1-hydroxycyclohexyl phenyl ketone type I (Irgacure 184).

[0465] Therefore, the photocrosslinkable composition X may further comprise a photoinitiator selected from the following: type II radical photoinitiators such as:

[0466] Benzophenone, for example 1-hydroxycyclohexyl benzophenone sold by IGM Resin B.V. under the name Omnirad TM The name of 184 for sale; Thioxanthone, for example isopropyl thioxanthone, thioxanthone neodecanoate or substituted thioxanthone, as disclosed in patent application WO 2018 / 234643; Xanthone, for example 9- xanthone; Anthraquinone and hydroxyanthraquinone, for example 4-dihydroxyanthraquinone, 2-methylanthraquinone, 2,2'-bis(3-hydroxy-1,4-naphthoquinone), 2,6-dihydroxyanthraquinone, 1,5-dihydroxyanthraquinone, 2-ethylanthraquinone, 2-methylanthraquinone, 1,8-dihydroxyanthraquinone, 1,3-diphenyl-1,3-propanedione, 5,7-dihydroxyflavone.

[0467] In one embodiment, the method of the present invention is characterized in that the weight average molecular weight of the radical photoinitiator B is 400 - 10,000 g / mol, preferably 400 - 5000, preferably 400 - 3000, even more preferably 400 - 2600 g / mol.

[0468] In one embodiment, the method of the present invention is characterized in that the mass percentage of the radical photoinitiator B, based on the total mass of the photocrosslinkable composition X, is 0.1% - 20%, preferably 0.1% - 5% based on the total mass of the photocrosslinkable composition X, preferably 0.2% - 2%, more preferably 0.4% - 1.5%.

[0469] In one embodiment, the method of the present invention is characterized in that the free radical photoinitiator B and the organopolysiloxane A are the same molecule, denoted as AB. This system is then referred to as an "intramolecular system".

[0470] In one embodiment, the method of the present invention is characterized in that the compound AB is a compound of formula (XXa), (XXb), (XXc) or (XXd):

[0471]

[0472] where

[0473] R 12 , which are the same or different, represent a hydrogen atom or a hydroxyl group;

[0474] R 13 , which are the same or different, represent:

[0475] - an alkenyl functional group having 2 to 4 carbon atoms,

[0476] - at least one group of formula (XXI):

[0477]

[0478] R1 and R2 represent the groups defined above;

[0479] R 14 represents;

[0480] - an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms:

[0481] - substituted or unsubstituted by at least one heteroatom O, N or S,

[0482] - substituted or unsubstituted by at least one alkyl group having 1 to 5 carbon atoms,

[0483] - substituted or unsubstituted by at least one aryl group having 6 to 18 carbon atoms,

[0484] - x1 is an integer from 1 to 1000; preferably x1 is from 1 to 500;

[0485] - n1 is an integer from 1 to 100, preferably n1 is from 2 to 50;

[0486] - x2 is an integer from 1 to 1000, preferably x2 is from 1 to 500;

[0487] - n2 is an integer from 0 to 100, preferably n2 is from 0 to 50;

[0488] - x3 is an integer from 1 to 1000, preferably x3 is from 1 to 500; and

[0489] - n3 is an integer from 0 to 100, preferably n3 is from 0 to 50

[0490] - x4 is an integer from 1 to 1000, preferably x3 is from 1 to 500; and

[0491] - n4 is an integer from 0 to 100, preferably n3 is from 0 to 50;

[0492] - m1, m2, m3 and m4 are integers from 1 to 8.

[0493] In one embodiment, the method of the present invention is characterized in that the compound AB is a compound of formula (XXIIa), (XXIIb), (XXIIc) or (XXIId):

[0494]

[0495]

[0496] Wherein:

[0497] R 14 , identical or different, represent:

[0498] - an alkenyl functional group having 2 to 4 carbon atoms,

[0499] - at least one group of formula (XXIII):

[0500]

[0501] Formula (XXIII)

[0502] R1 and R2 represent the groups defined above;

[0503] R 15 represents;

[0504] - an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms:

[0505] - substituted or unsubstituted by at least one heteroatom O, N or S,

[0506] - substituted or unsubstituted by at least one alkyl group having 1 to 5 carbon atoms,

[0507] - substituted or unsubstituted by at least one aryl group having 6 to 18 carbon atoms,

[0508] - x1 is an integer from 1 to 1000; preferably x1 is from 1 to 500;

[0509] - n1 is an integer from 0 to 100, preferably n1 is from 0 to 50;

[0510] - x2 is an integer from 1 to 1000, preferably x2 is from 1 to 500;

[0511] - n2 is an integer from 1 to 100, preferably n2 is from 2 to 50;

[0512] - x3 is an integer from 1 to 1000, preferably x3 is from 1 to 500;

[0513] - n3 is an integer from 1 to 100, preferably n3 is from 0 to 50

[0514] - x4 is an integer from 1 to 1000, preferably x4 is from 1 to 500;

[0515] - n4 is an integer from 0 to 100, preferably n4 is from 0 to 50.

[0516] Other additives:

[0517] In one embodiment, the method of the present invention is characterized in that the photocrosslinkable organosilicon composition X comprises:

[0518] - 10 - 99.9% of at least one organopolysiloxane A containing at least one (meth)acrylate group as defined above

[0519] - 0.1 - 20% of at least one radical photoinitiator B as defined above.

[0520] The photocrosslinkable organosilicon composition X may further comprise other additives such as polymerization inhibitors, fillers, virucides, fungicides, antiwear additives and pigments (organic or inorganic).

[0521] Among the polymerization inhibitors, mention may be made of phenol, hydroquinone, 4 - OMe - phenol, 2,4,6 - tris(tert - butyl)phenol (BHT), phenothiazine and nitroxyl radicals such as (2,2,6,6 - tetramethylpiperidin - 1 - yl)oxy (TEMPO).

[0522] The photocrosslinkable organosilicon composition X may further comprise an organic compound O containing at least one (meth)acrylate functional group.

[0523] The term "organic compound O containing at least one (meth)acrylate functional group" refers to any compound containing one or more (meth)acrylate functional groups.

[0524] According to one embodiment, the organic compound O containing at least one (meth)acrylate functional group does not contain a siloxane structure.

[0525] Particularly suitable as the organic compound O containing a (meth)acrylate functional group are epoxidized (meth)acrylates, (meth)acrylglycerol polyesters, (meth)acrylamides, (meth)acrylpolyethers, (meth)acrylpolliesters, and (meth)acrylacrylic compounds. Even more preferably are trimethylolpropane triacrylate, dipropylene glycol diacrylate, hexanediol diacrylate, and pentaerythritol tetraacrylate.

[0526] As examples of the organic compound O containing a (meth)acrylate functional group, mention may be made, for example, of ethylhexyl acrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, isodecyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, cyclohexyl acrylate, isooctyl acrylate, tridecyl acrylate, isobornyl acrylate, caprolactone acrylate, alkoxylated phenol acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, and triethylene glycol diacrylate, dipropylene glycol diacrylate, alkoxylated hexanediol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol pentaacrylate.

[0527] The photocrosslinkable silicone composition X may contain 0 - 50% of the organic compound O, based on the total mass of the photocrosslinkable silicone composition X.

[0528] According to one embodiment, the photocrosslinkable silicone composition X further contains a filler D.

[0529] The photocrosslinkable silicone composition X may contain 0 - 50% by mass of the filler D, preferably 10% - 50% by mass of the filler D, preferably 10% - 40% by mass of the filler D, and even more preferably 20% - 35% by mass of the filler D, based on the total mass of the photocrosslinkable silicone composition X.

[0530] According to one embodiment, the photocrosslinkable silicone composition X contains 20% - 30% by mass of the filler D, based on the total mass of the photocrosslinkable silicone composition X.

[0531] This filler is preferably a mineral filler. The filler D may be a very finely divided product with an average particle size of less than 0.1 μm.

[0532] The filler D may in particular be siliceous. Regarding siliceous materials, they may serve as reinforcing or semi-reinforcing fillers. The reinforcing siliceous fillers are selected from colloidal silica, fumed and precipitated silica powders, or mixtures thereof.

[0533] These powders generally have an average particle size of less than 0.1 μm (micrometer), and a BET specific surface area of greater than 30 m 2 / g, preferably 30 - 350 m 2 / g.

[0534] Semi - reinforcing siliceous fillers such as diatomaceous earth or ground quartz can also be used.

[0535] These silicas can be incorporated as such, or after treatment with organosilicon compounds commonly used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinyl ethoxysilane, trimethylmethoxysilane, and mixtures thereof. Regarding non - siliceous minerals, they can be used as semi - reinforcing or extender mineral fillers.

[0536] Examples of these non - siliceous fillers that can be used alone or as a mixture are calcium carbonate, optionally surface - treated with an organic acid or an ester of an organic acid, calcined clay and rutile - type titanium oxide, oxides of iron, zinc, chromium, zirconium, and magnesium, various forms of alumina (hydrated or unhydrated), boron nitride, lithopone, barium metaborate, barium sulfate, and glass microspheres.

[0537] These fillers are coarser, generally having an average particle diameter of greater than 0.1 μm and a specific surface area usually less than 30 m 2 / g.

[0538] These fillers may have been surface - modified by treatment with various organosilicon compounds commonly used for this purpose.

[0539] Thus, according to one embodiment, the method of the present invention is characterized in that the photocrosslinkable organosilicon composition X comprises:

[0540] - 10 - 89.9% of at least one organic polysiloxane A as defined above containing at least one (meth)acrylate group

[0541] - 0.1 - 20% of at least one radical photoinitiator B as defined above;

[0542] - 10 - 50% of filler D.

[0543] The photocrosslinkable organosilicon composition X may further comprise a light absorber E.

[0544] The light absorber E allows reducing the penetration of irradiation into the layer of the photocrosslinkable silicone composition X, and thus improves the resolution of the obtained silicone elastomer article. It enables controlling the penetration depth (Dp) of irradiation in the silicone elastomer layer.

[0545] The photocrosslinkable silicone composition X contains 0.01% - 5% by mass of the light absorber E, based on the total mass of the photocrosslinkable silicone composition X, and preferably, the light absorber E is selected from TiO2, ZnO, hydroxyphenyl-s-triazine, hydroxyphenyl-benzotriazole such as 384 - 2, cyanoacrylate, and mixtures thereof. According to one embodiment of the present invention, the photocrosslinkable silicone composition X contains 0.01% - 1.5% by mass, preferably 0.01% - 0.5% by mass, preferably 0.01% - 0.2% by mass of the light absorber E, based on the total mass of the photocrosslinkable silicone composition X.

[0546] The photocrosslinkable silicone composition X may further contain a light stabilizer F.

[0547] The light stabilizer F reduces or even stops the activity of the photoinitiator by capturing the free radicals that are still active after implementing the method of the present invention. This thus allows improving the transparency properties of the silicone elastomer article obtained according to the method of the present invention.

[0548] The photocrosslinkable silicone composition X further contains 0 - 2% by mass of the light stabilizer F, based on the total mass of the photocrosslinkable silicone composition X, and preferably 0 - 0.5% by mass of the light stabilizer F, based on the total mass of the photocrosslinkable silicone composition X.

[0549] The light stabilizer F is selected from hindered amines, cyclic amines having 4 - 6 carbon atoms, such as the commercial compounds 249, 292, 123 and mixtures thereof.

[0550] Photocrosslinkable composition X2 :

[0551] The present invention also relates to a photocrosslinkable silicone composition X2, which comprises:

[0552] - 10 - 99.9% by mass of at least one organopolysiloxane A containing at least one (meth)acrylate group;

[0553] - 0.1 - 20% by mass of at least one free radical photoinitiator B, which is a compound of formula (I):

[0554]

[0555] Wherein,

[0556] R represents a linear or branched C1-C 50 alkylene or heteroalkylene, preferably a linear or branched C1-C 18 alkylene or heteroalkylene, said alkylene and heteroalkylene containing at least one siloxane functional group;

[0557] R1 represents a group of formula (II):

[0558]

[0559] wherein Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0560] - an alkyl group having 1 to 6 carbon atoms,

[0561] - an alkenyl group having 2 to 4 carbon atoms,

[0562] - a heteroatom O, N or S,

[0563] - a halogen,

[0564] - a SiMe3 group,

[0565] - a hydroxyl group (OH),

[0566] - a (O-Alk) group, wherein Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5;

[0567] R2 represents:

[0568] - a group R1,

[0569] - an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0570] - an alkyl group having 1 to 6 carbon atoms,

[0571] - an alkenyl group having 2 to 4 carbon atoms,

[0572] - a heteroatom O, N or S,

[0573] - a halogen,

[0574] - a SiMe3 group,

[0575] - a hydroxyl group (OH),

[0576] - a (O-Alk) group, wherein Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5.

[0577] Advantageously, photoinitiator B of the photocrosslinkable composition X2 is a compound selected from the following: compounds of formula (VIII), (XIII), (XVII), (XXa), (XXb), (XXc), (XXd) and / or mixtures thereof.

[0578] Preferably, photoinitiator B of the photocrosslinkable composition X2 is a compound selected from the following: compounds of formula (VIII), (XIII), (XVII), (XXa) and / or mixtures thereof.

[0579] Thus, according to one embodiment, the photocrosslinkable silicone composition X2 comprises:

[0580] - 10 - 99.9% by mass of at least one organopolysiloxane A containing at least one (meth)acrylate group;

[0581] - 0.1 - 20% by mass of at least one photoinitiator B, which is a compound of formula (XXIV):

[0582]

[0583] wherein, R9, which may be the same or different, represents:

[0584] - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl,

[0585] - an aryl group containing 6 - 10 carbon atoms, preferably phenyl,

[0586] - an alkenyl group containing 2 - 6 carbon atoms, preferably vinyl,

[0587] - hydroxy (OH),

[0588] - (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5,

[0589] - (O - Alk) x group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, and x represents an integer from 2 - 200,

[0590] - acrylate or methacrylate group,

[0591] - a linear or branched alkyl group containing 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, such as (C1-C5)alkyl-CF3, and the alkyl group is linear or branched,

[0592] - an amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group containing 1 to 5 carbon atoms,

[0593] - a carbonyl or carboxyl group,

[0594] - hydrogen,

[0595] - a group of formula (XXV):

[0596]

[0597] wherein R1 and R2 represent groups as defined above,

[0598] R6 represents a linear or branched C1-C 50 alkylene or heteroalkylene group, preferably a linear or branched C1-C 18 alkylene or heteroalkylene group;

[0599] R 10 , which are the same or different, represent:

[0600] - an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0601] - an aryl group containing 6 to 10 carbon atoms, preferably phenyl,

[0602] - an alkenyl group containing 2 to 6 carbon atoms, preferably vinyl,

[0603] - hydroxyl (OH),

[0604] - a (O-Alk) group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0605] - (O-Alk) x group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0606] - an acrylate or methacrylate group,

[0607] - a linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, such as (C1 - C5)alkyl - CF3, and the alkyl group is linear or branched,

[0608] - an amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group containing 1 - 5 carbon atoms,

[0609] - a carbonyl or carboxyl group,

[0610] - hydrogen,

[0611] R 11 represents the group -CH3 or an oxygen atom;

[0612] Z represents the group -CH2- or an oxygen atom;

[0613] Ar represents an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0614] - an alkyl group having 1 - 6 carbon atoms,

[0615] - an alkenyl group having 2 - 4 carbon atoms,

[0616] - a heteroatom O, N or S,

[0617] - a halogen,

[0618] - a SiMe3 group,

[0619] - a hydroxyl group (OH),

[0620] - a (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5;

[0621] m represents a natural integer from 1 to 8;

[0622] p represents a natural integer equal to 0 or 1;

[0623] q represents a natural integer from 0 to 100;

[0624] a represents a natural integer equal to 1 or 2;

[0625] b represents a natural integer from 0 to 100.

[0626] According to one embodiment, the photocrosslinkable silicone composition X2 is characterized in that the free - radical photoinitiator B is a compound of formula (XIX) as indicated above:

[0627] wherein, R9 and R10 , identical or different, represent:

[0628] - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0629] - hydroxy (OH),

[0630] - a hydrogen atom

[0631] R 11 represents the group -CH3 or an oxygen atom;

[0632] Z represents the group -CH2- or an oxygen atom;

[0633] Ar represents an aryl group having 6 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0634] - an alkyl group having 1 to 6 carbon atoms,

[0635] - an alkenyl group having 2 to 4 carbon atoms,

[0636] - a heteroatom O, N or S,

[0637] - a halogen,

[0638] - a SiMe3 group,

[0639] - hydroxy (OH),

[0640] m represents a natural integer from 1 to 8;

[0641] p represents a natural integer equal to 0 or 1;

[0642] q represents a natural integer from 0 to 10;

[0643] a represents a natural integer equal to 1 or 2;

[0644] b represents a natural integer from 0 to 20.

[0645] In a preferred embodiment, the photocrosslinkable organosilicon composition X2 comprises:

[0646] - 25 to 89.9% by mass of at least one organopolysiloxane A containing at least one (meth) acrylate group;

[0647] - 10 to 50% of a filler D;

[0648] - 0.1 to 15% by mass of at least one free radical photoinitiator B, which is a compound of formula (XXVI):

[0649]

[0650] wherein, R9, identical or different, represent:

[0651] - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0652] - an aryl group having 6 to 10 carbon atoms, preferably phenyl,

[0653] - an alkenyl group having 2 to 6 carbon atoms, preferably vinyl,

[0654] - hydroxy (OH),

[0655] - (O - Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0656] - (O - Alk) x group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0657] - acrylate or methacrylate group,

[0658] - a linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, and the alkyl is linear or branched,

[0659] - an amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group having 1 to 5 carbon atoms,

[0660] - carbonyl or carboxyl,

[0661] - hydrogen,

[0662] - a group of formula (XXVII):

[0663]

[0664] where R1 and R2 represent groups as defined above,

[0665] R6 represents a linear or branched C1 - C 50 alkylene or heteroalkylene, preferably linear or branched C1 - C 18 alkylene or heteroalkylene;

[0666] R 10 , which are the same or different, represent:

[0667] - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0668] - an aryl group having 6 to 10 carbon atoms, preferably phenyl,

[0669] - an alkenyl group having 2 to 6 carbon atoms, preferably vinyl,

[0670] - hydroxy (OH),

[0671] - (O - Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5,

[0672] - (O - Alk) x group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200,

[0673] - acrylate or methacrylate group,

[0674] - a linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, and the alkyl is linear or branched,

[0675] - an amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group having 1 to 5 carbon atoms,

[0676] - carbonyl or carboxyl,

[0677] - hydrogen,

[0678] R 11 represents the group - CH3 or an oxygen atom;

[0679] Z represents the group - CH2 - or an oxygen atom;

[0680] Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0681] - an alkyl group having 1 to 6 carbon atoms,

[0682] - an alkenyl group having 2 to 4 carbon atoms,

[0683] - heteroatoms O, N or S,

[0684] - halogen,

[0685] -SiMe3 group

[0686] - hydroxyl (OH)

[0687] -(O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5

[0688] m represents a natural integer from 1 to 8

[0689] p represents a natural integer equal to 0 or 1

[0690] q represents a natural integer from 0 to 100

[0691] a represents a natural integer equal to 1 or 2

[0692] b represents a natural integer from 0 to 100

[0693] In a particularly preferred embodiment, the photocrosslinkable silicone composition X2 is characterized in that the free radical photoinitiator B represented by formula (XXVI) is further defined as: when a = 1, q > 0 or at least one group R9 is hydroxyl

[0694] According to one embodiment, the photocrosslinkable silicone composition X2 is characterized in that the free radical photoinitiator B is a compound of formula (XXVI) as indicated above

[0695] where R9 and R 10 , which are the same or different, represent

[0696] - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl

[0697] - hydroxyl (OH)

[0698] - hydrogen atom

[0699] R 11 represents the group - CH3 or an oxygen atom

[0700] Z represents the group - CH2 - or an oxygen atom

[0701] Ar represents an aryl group of 6 carbon atoms, which is substituted or unsubstituted by at least one of the following groups

[0702] - an alkyl group of 1 - 6 carbon atoms

[0703] - an alkenyl group of 2 - 4 carbon atoms

[0704] - heteroatoms O, N or S

[0705] - Halogen,

[0706] - SiMe3 group,

[0707] - Hydroxy group (OH),

[0708] m represents a natural integer from 1 to 8;

[0709] p represents a natural integer equal to 0 or 1;

[0710] q represents a natural integer from 0 to 10;

[0711] a represents a natural integer equal to 1 or 2;

[0712] b represents a natural integer from 0 to 20;

[0713] And when a = 1: q > 0 or at least one group R9 is a hydroxy group.

[0714] The photocrosslinkable silicone composition X2 further comprises at least one additive.

[0715] In a preferred embodiment, the additive is a filler, a light absorber or a light stabilizer and mixtures thereof.

[0716] The photocrosslinkable silicone composition X2 can be used in a very diverse range of technical fields such as printing inks, printing technology, varnishes, wood coatings, plastic coatings, metal coatings, adhesives and 3D printing.

[0717] Therefore, it can be used with coating tools for the preparation of silicone anti - sticking coatings.

[0718] The present invention also relates to a method for preparing a coating on a support, comprising the following steps:

[0719] - Applying the photocrosslinkable silicone composition X2 to the support, and

[0720] - Crosslinking the composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays or by exposure to radiation having a wavelength of 200 nm - 450 nm, in particular UV radiation.

[0721] Advantageously, the photoinitiator B of the photocrosslinkable composition X2 is a compound selected from the following: compounds of formula (VIII), (XIII), (XVII), (XXa), (XXb), (XXc), (XXd) and / or mixtures thereof.

[0722] Preferably, the photoinitiator B of the photocrosslinkable composition X2 is a compound selected from the following: compounds of formula (VIII), (XIII), (XVII), (XXa) and / or mixtures thereof.

[0723] The solvent-free (i.e., undiluted) photocrosslinkable silicone composition X2 according to the invention can be applied using a device capable of uniformly depositing small amounts of liquid. For this purpose, for example, a "Helio Glissant" device can be used, which particularly includes two superimposed rollers: the lower roller is immersed in a coating bath containing the composition, and its role is to impregnate the upper roller with a very thin layer, while the latter's role is to deposit the desired amount of the composition to be impregnated on the paper, and this dosage is achieved by adjusting the respective speeds of the two rollers rotating in opposite directions.

[0724] The crosslinking reflected by the curing of the photocrosslinkable silicone composition X2 can be carried out continuously by the following operation: passing the carrier coated with the composition through an irradiation device, which is designed to provide the coated carrier with a residence time sufficient to complete the curing of the coating.

[0725] Preferably, the curing is carried out at the lowest possible oxygen concentration, usually the oxygen concentration is less than 100 ppm, preferably less than 50 ppm. The curing is usually carried out in an inert atmosphere, for example, in nitrogen or argon.

[0726] The exposure time required to cure the silicone composition X2 varies depending on factors such as the following:

[0727] - The specific formulation used, the type and wavelength of the radiation,

[0728] - The dose rate, energy flux,

[0729] - The concentration of the free radical photoinitiator, and

[0730] - The atmosphere and thickness of the coating.

[0731] These parameters are well known to those skilled in the art, and those skilled in the art can adjust them.

[0732] The amount of the photocrosslinkable silicone composition X2 deposited on the carrier is variable and is usually 0.1 - 5 g / m 2 of the treated surface area. These amounts depend on the nature of the carrier and the desired anti-sticking properties. For non-porous carriers, they are usually 0.5 - 1.5 g / m 2 .

[0733] This method is particularly suitable for preparing a silicone anti-stick coating on a support, which is a flexible support made of textiles, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane or non-woven glass fiber.

[0734] The flexible support coated with an anti-stick silicone coating can be, for example:

[0735] - A polymer film of paper or polyolefin type (polyvinyl chloride (PVC), polypropylene or polyethylene) or polyester type (polyethylene terephthalate or PET),

[0736] - A tape, the inner surface of which is coated with a pressure-sensitive adhesive layer and the outer surface of which includes a silicone anti-stick coating;

[0737] - Or a polymer film for protecting the adhesive surface of a pressure-sensitive adhesive or a self-adhesive element.

[0738] These coatings are particularly suitable for the anti-stick field.

[0739] The present invention also relates to a coated support obtainable according to the above method. As described above, the support can be a flexible support made of textiles, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane or non-woven glass fiber.

[0740] The coated support has anti-stick and waterproof properties, or enables improved surface properties such as smoothness, stain resistance or softness.

[0741] Another subject of the present invention relates to the use of a support at least partially coated with an anti-stick coating according to the present invention and as defined above in the fields of self-adhesive labels, tapes including envelopes, graphic arts, healthcare and hygiene.

[0742] The present invention also relates to a photoinitiator of formula (XXVIII)

[0743]

[0744] Wherein:

[0745] R9, which are the same or different, represent:

[0746] - An alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably methyl,

[0747] - An aryl group containing 6-10 carbon atoms, preferably phenyl,

[0748] - An alkenyl group containing 2-6 carbon atoms, preferably vinyl,

[0749] - Hydroxy (OH),

[0750] - (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5,

[0751] - (O - Alk) x group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, and x represents an integer from 2 - 200,

[0752] - Acrylate or methacrylate group,

[0753] - A linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, and the alkyl is linear or branched,

[0754] - An amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group containing 1 - 5 carbon atoms,

[0755] - Carbonyl or carboxyl group,

[0756] - Hydrogen,

[0757] - A group of formula (XXIX):

[0758]

[0759] where R1 and R2 represent the groups defined above,

[0760] R6 represents a linear or branched C1 - C 50 alkylene or heteroalkylene, preferably a linear or branched C1 - C 18 alkylene or heteroalkylene;

[0761] R 10 , which are the same or different, represent:

[0762] - An alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl,

[0763] - An aryl group containing 6 - 10 carbon atoms, preferably phenyl,

[0764] - An alkenyl group containing 2 - 6 carbon atoms, preferably vinyl,

[0765] - Hydroxy group (OH),

[0766] - (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5,

[0767] - (O - Alk) x group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, and x represents an integer from 2 - 200,

[0768] - Acrylate or methacrylate group,

[0769] - A linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, and the alkyl group is linear or branched,

[0770] - An amino group selected from (Alk) - NH2 or (Alk) - NH - (Alk) - NH2, where Alk represents an alkyl group containing 1 - 5 carbon atoms,

[0771] - Carbonyl or carboxyl group,

[0772] - Hydrogen,

[0773] R 11 represents the group - CH3 or an oxygen atom;

[0774] Z represents the group - CH2 - or an oxygen atom;

[0775] Ar represents an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0776] - An alkyl group having 1 - 6 carbon atoms,

[0777] - An alkenyl group having 2 - 4 carbon atoms,

[0778] - A heteroatom O, N or S,

[0779] - A halogen,

[0780] - SiMe3 group,

[0781] - Hydroxy group (OH),

[0782] - (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5;

[0783] m represents a natural integer from 1 to 8;

[0784] p represents a natural integer equal to 0 or 1;

[0785] q represents a natural integer from 0 to 100;

[0786] a represents a natural integer equal to 1 or 2;

[0787] b represents a natural integer from 0 to 100;

[0788] The photoinitiator is characterized in that when a = 1,

[0789] q > 0 or at least one group R9 is a hydroxyl group.

[0790] According to one embodiment, the present invention also relates to a compound of formula (XXVIII) indicated above:

[0791] wherein R9 and R 10 , which are the same or different, represent:

[0792] - an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl,

[0793] - hydroxyl (OH),

[0794] - a hydrogen atom

[0795] R 11 represents the group -CH3 or an oxygen atom;

[0796] Z represents the group -CH2- or an oxygen atom;

[0797] Ar represents an aryl group of 6 carbon atoms, which is substituted or unsubstituted by at least one of the following groups:

[0798] - an alkyl group of 1 to 6 carbon atoms,

[0799] - an alkenyl group of 2 to 4 carbon atoms,

[0800] - a heteroatom O, N or S,

[0801] - a halogen,

[0802] - the SiMe3 group,

[0803] - hydroxyl (OH),

[0804] m represents a natural integer from 1 to 8;

[0805] p represents a natural integer equal to 0 or 1;

[0806] q represents a natural integer from 0 to 10;

[0807] a represents a natural integer equal to 1 or 2;

[0808] b represents a natural integer from 0 to 20;

[0809] And when a = 1: q > 0 or at least one group R9 is a hydroxyl group. Detailed implementation mode

[0810] Examples

[0811] Organopolysiloxane A used in the examples

[0812]

[0813] This molecular weight M w The organosilicon acrylate polymer with a molecular weight of 7654 g / mol is labeled as polymer a1 in the following examples.

[0814]

[0815] This molecular weight M w The organosilicon acrylate polymer with a molecular weight of 18,714 g / mol is labeled as polymer a2 in the following examples.

[0816]

[0817] This molecular weight M w The organosilicon acrylate polymer with a molecular weight of 18,862 g / mol is labeled as polymer a3 in the following examples.

[0818]

[0819] This molecular weight M w The organosilicon acrylate polymer with a molecular weight of 8297 g / mol is labeled as polymer a4 in the following examples.

[0820]

[0821] This molecular weight M w The organosilicon acrylate polymer with a molecular weight of 2340 g / mol is labeled as polymer a5 in the following examples.

[0822] Photoinitiator B used in the examples :

[0823] In the following examples, the Mes group represents a mesityl group represented by the following formula:

[0824]

[0825] The photoinitiator of the present invention labeled B1 has a weight-average molecular weight M of 2,600 g / mol w 。

[0826]

[0827] The photoinitiator of the present invention labeled B2 has a weight-average molecular weight M of 690 g / mol w 。

[0828]

[0829] The photoinitiator of the present invention labeled B3 has a weight-average molecular weight M of 764 g / mol w 。

[0830] Comparative photoinitiator C :

[0831]

[0832] This photoinitiator is ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate named TPO-L (CAS 84434-11-7), and will be labeled C1 in the following examples. This comparative photoinitiator has a weight-average molecular weight M of 316 g / mol w 。

[0833]

[0834] This photoinitiator is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide named BAPO (CAS 162881-26-7), and will be labeled C2 in the following examples. This comparative photoinitiator has a weight-average molecular weight M of 418 g / mol w 。

[0835] Additives used in the examples :

[0836] Filler D1: Fumed silica treated with SiMe3 groups on the surface, BET specific surface area is 200 m 2 / g

[0837] Physical and / or mechanical properties :

[0838] Viscosity :In the context of this patent application, viscosity is measured using a Brookfield CAP 1000+ / CAP 2000+ viscometer. These ICI-type viscometers with cone-plate geometry and forced speed allow for rapid measurement of small sample volumes at a controlled temperature. Characterization is performed at high shear rates.

[0839] The viscosity of the sample was measured at 25 °C according to the standard ASTM D4287.

[0840] Hardness : The hardness of the crosslinked sample was measured at 25 °C according to the standard ASTM D2240 or ISO868.

[0841] Elongation at break and tensile strength : These two physical quantities of the crosslinked sample were measured at 25 °C according to the standard ASTM D412.

[0842] Modulus of elasticity at 100% elongation : This physical quantity of the sample was measured at 25 °C according to the standard ASTM D412.

[0843] Tear strength : This physical quantity of the sample was measured at 25 °C by a "lentil-shaped specimen" according to the standard ISO-34-2.

[0844] Touchercollant : The tackiness of the sample was qualitatively measured at 25 °C by placing the index finger on the surface of the sample to be characterized. Once the index finger was placed on the surface of the sample, pressure was applied with the index finger and then the finger was withdrawn to evaluate the tacky or non-tacky feeling of the surface of the sample.

[0845] In the above embodiment, the characterized sample surface is the last layer of the crosslinked sample.

[0846] Photocrosslinkable composition :

[0847] In the context of the embodiments of the present invention, when a photocrosslinkable silicone composition that is stable over a long period of up to several months is desired, 10 - 1000 ppm of a stabilizer, such as 4-methoxyphenol, can be added to the composition.

[0848] Comparative photocrosslinkable composition :

[0849] Composition C1 : In the context of the following embodiments, composition C1 was formed from photoinitiator C1 present in X% by mass relative to the total mass of the composition. The obtained composition C1 was manually mixed for 2 minutes until the solution was clear.

[0850] Composition C2 : In the context of the following embodiments, composition C2 was formed from photoinitiator C2 present in X% by mass relative to the total mass of the composition. The obtained composition C2 was manually mixed for 2 minutes until the solution was clear.

[0851] Photocrosslinkable composition according to the invention :

[0852] Composition 1: In the context of the following examples, Composition 1 is formed by photoinitiator B1 present at X% by mass relative to the total mass of the composition. The obtained Composition 1 is manually mixed for 2 minutes until the solution is clear.

[0853] Composition 2 : In the context of the following examples, Composition 2 is formed by photoinitiator B2 present at X% by mass relative to the total mass of the composition. The obtained Composition 2 is manually mixed for 2 minutes until the solution is clear.

[0854] Composition 3 : In the context of the following examples, Composition 3 is formed by photoinitiator B3 present at X% by mass relative to the total mass of the composition. The obtained Composition 3 is manually mixed for 2 minutes until the solution is clear.

[0855] It should be noted that the mass percentage of each photoinitiator labeled as X% above is specifically indicated in each example of this patent application.

[0856] It should be noted that the examples according to the present invention are carried out without using solvents or cosolvents to dissolve the photocrosslinkable composition.

[0857] In the following examples, Composition 1a1 represents Composition 1 implemented with polymer a1 as the organopolysiloxane A.

[0858] Composition 1a2 represents Composition 1 implemented with polymer a2 as the organopolysiloxane A.

[0859] In the specific case where a mixture of organopolysiloxanes a1 and a3 is present in Composition 2, it will be labeled as Composition 2a1 + a3.

[0860] Composition C1a3 will represent Composition C1 implemented with polymer a3 as the organopolysiloxane A. Similarly, Compositions 1, 2, and 3 will be represented as described above.

[0861] Materials and devices :

[0862] The ASIGA Max 3D printer is a (DLP) 3D printer: before adding to the 1L tank of the device (print volume XYZ: 119x67x75mm 3 )), the photocrosslinkable composition is mixed manually or using a mixer. Then, a specimen with a thickness of 2mm + / - 0.1 (i.e., 75μm per layer) consisting of 27 layers is designed by computer programming. Unless otherwise specified, in this patent application, at 385nm and at the energy defined in the examples, the first layer is irradiated for 20s, and the subsequent layers are irradiated for a duration of 5s per layer.

[0863] The Anycubic Photon Mono 6K printer is a (LCD) 3D printer: in this case, light from a set of 405nm LEDs is projected through an LCD screen which acts as a mask and only shows the pixels required for the printed model.

[0864] Before adding to the 1L tank of the device (print volume XYZ: 192x120x245mm 3 ) the photocrosslinkable composition is mixed manually or using a mixer. Then a specimen with a thickness of 2mm + / - 0.1 consisting of 27 layers (i.e., 75μm per layer) is designed by computer programming. Unless otherwise stated, in this patent application, at 405nm and at the energy defined in the examples, the first layer is irradiated for 40s and the subsequent layers are irradiated for a duration of 20s per layer

[0865] Example 1: Synthesis of photoinitiator B

[0866] The various photoinitiators of the present invention are prepared according to a preparation method similar to the preparation method disclosed in patent application WO2014 / 053455.

[0867] Example 2: Solubility test :

[0868] To evaluate the solubility of photoinitiators B1, B2 and B3 of the present invention, photocrosslinkable compositions 1a1, 1a2, 2a1, 2a2, 3a1 and 3a2 are prepared.

[0869] In parallel, comparative photocrosslinkable compositions C1a1 and C2a2 are also prepared.

[0870] These tests are carried out at two different mass percentages. First, the photocrosslinkable compositions (1a1, 1a2, 2a1, 2a2, 3a1 and 3a2) contain 1% by mass of photoinitiator relative to the total mass of the composition. Second, the photocrosslinkable compositions (1a1 and 2a1) contain 10% by mass of photoinitiator relative to the total mass of the composition.

[0871] After manually stirring the different samples, the solubility of these different photoinitiators is visually observed with the naked eye.

[0872] The following table shows the solubility of the different photoinitiators of the present invention.

[0873] Table 1: Solubility study of different photoinitiators

[0874]

[0875] It should be noted that the comparative photocrosslinkable compositions C1a1 and C1a2 with photoinitiator C1 are turbid at the different mass percentages shown in the above table.

[0876] The insolubility of photoinitiator C1 in organopolysiloxane A (a1 and a2) makes it difficult to use in additive manufacturing methods such as those described in the present invention. The addition of a solvent may prove necessary to dissolve such a system.

[0877] In fact, turbidity was visually observed starting from 1% by mass of photoinitiator C1 relative to the weight of organopolysiloxane A, and this turbidity increased when increasing the mass percentage of photoinitiator C1 relative to the total mass of the composition. On the other hand, photoinitiators B1, B2, and B3 of the present invention have satisfactory solubility in organopolysiloxane A (a1 and a2) at the different mass percentages shown in the table above.

[0878] Example 3: Research and characterization of the photocrosslinkable composition according to the invention:

[0879] Example 3a :

[0880] Table 2: Summary table of the photocrosslinkable compositions used:

[0881]

[0882] The molar amount of phosphorus atoms present in the photocrosslinkable composition makes it possible to approximately estimate the amount of active substance material in the photocrosslinkable composition under study.

[0883] Therefore, it should be noted that the photocrosslinkable composition of the present invention in Example 3 has a small amount of active substance material compared to the comparative composition C1a2.

[0884] Example 3b: Crosslinking depth of the photocrosslinkable composition according to the method of the invention .

[0885] In the context of this example, the organopolysiloxane A used in the different photocrosslinkable compositions is polymer a2.

[0886] This example aims to compare the crosslinking depth of the photocrosslinkable composition according to the present invention (2a2) and the comparative photocrosslinkable composition (C1a2), as described in Table 2.

[0887] The following Table 3 shows the crosslinking depth values of different photocrosslinkable compositions according to the energy used (5 mW / cm 2 or 11 mW / cm 2 ).

[0888] Table 3: Crosslinking depth measurement (μm)

[0889]

[0890] It should be noted that at low light intensities, a greater crosslinking depth is obtained using the photocrosslinkable composition 2a2 of the present invention than using the comparative composition C1a2.

[0891] Under these conditions, it was observed that at 5 mW / cm 2 , the photocrosslinkable composition 2a2 reached the gel point (measurable non-liquid thickness) after 12 s, while the comparative photocrosslinkable composition C1a2 did not show a gel point until 18 s.

[0892] Example 3b: Evaluation of the mechanical properties of the specimen (without filler) obtained according to the method of the invention

[0893] The physical and mechanical properties of specimens prepared from the photocrosslinkable composition of Example 3a according to the method of the present invention were tested.

[0894] These properties were tested at two different energy values, namely 5 mW / cm 2 and 11 mW / cm 2 .

[0895] The 3D printer used was an ASIGA Max at 385 nm; the first layer was irradiated for 80 s and each of the subsequent layers was irradiated for 20 s to obtain specimens and enable the evaluation of mechanical properties.

[0896] Table 4 below mentions the mechanical and physical properties of the specimens at different energy values, such as elongation at break, breaking strength, modulus of elasticity at 100%, hardness, and stickiness. The mechanical property values shown are the average results obtained from measurements on 4 different specimens printed simultaneously.

[0897] Table 4: Measurement of the mechanical and physical properties of different specimens

[0898]

[0899] Table 4 above shows that the two specimens produced according to the method of the present invention have satisfactory mechanical properties.

[0900] Moreover, it was observed that, unlike the comparative specimen C1a2, the specimens obtained according to the method of the present invention do not have any stickiness. The non-stickiness property enables the limitation of the post-treatment steps before the subsequent application of the specimens obtained according to the method of the present invention.

[0901] Example 4: Research and characterization of the photocrosslinkable composition of the invention:

[0902] Example 4a:

[0903] Table 5: Summary table of the photocrosslinkable compositions used:

[0904]

[0905] The molar amount of phosphorus atoms present in the photocrosslinkable composition enables an approximate estimation of the amount of active substance material in the photocrosslinkable composition under study.

[0906] Thus, it should be noted that the photocrosslinkable composition of the present invention in Example 4 has a small amount of active substance material compared to the comparative compositions C1a3 and C2a3.

[0907] Example 4b: Evaluation of the crosslinking depth of the photoinitiator of the invention :

[0908] In the context of this example, the organopolysiloxane A used in the different photocrosslinkable compositions is polymer a3. This example aims to compare the crosslinking depths of the photocrosslinkable compositions (1a3 and 2a3) of the present invention and the comparative photocrosslinkable composition (C1a2), as shown in Table 5.

[0909] Table 6: Measurement of the crosslinking depth values of different compositions varying with the energy used (5 mW / cm 2 , 11 mW / cm 2 or 21 mW / cm 2 ).

[0910]

[0911] Then, it should be noted that the comparative photocrosslinkable composition C2a3 (BAPO) does not result in any crosslinking.

[0912] On the other hand, the photocrosslinkable compositions 1a3 (photoinitiator B1) and 2a3 (photoinitiator B2) of the present invention have a satisfactory crosslinking depth like the comparative composition C1a3 (TPO-L).

[0913] Example 4c: Evaluation of the mechanical properties of the specimen obtained by 3D printing without filler :

[0914] Test the physical and mechanical properties of the specimens prepared from the photocrosslinkable composition of Example 4a according to the method of the present invention. It should be recalled that the photocrosslinkable composition 2a3 shown in the following table has a photoinitiator mass percentage of 0.5% by mass relative to the total mass of the composition. The photocrosslinkable compositions 1a3, C1a3, and C2a3 contain a photoinitiator of 0.7% by mass relative to the total mass of the composition.

[0915] The 3D printer used is an ASIGA Max at 385 nm; the first layer is irradiated for 80 s, and each of the subsequent layers is irradiated for 20 s to obtain the specimens and enable the evaluation of the mechanical properties.

[0916] In the context of this test, overexposure is intentionally applied to obtain the total conversion of the acrylate and preliminarily evaluate the photoinitiator system.

[0917] The following Table 7 mentions at 11 mW / cm2 At the energy of, the mechanical and physical properties of the specimen such as elongation at break, breaking strength, elastic modulus at 100%, hardness and stickiness. The shown mechanical property values are the average results obtained from the measurements of at least three different specimens printed simultaneously.

[0918]

[0919] Table 7 above shows that specimens with satisfactory mechanical properties cannot be obtained from the photocrosslinkable composition C2a3 (BAPO).

[0920] On the other hand, the photocrosslinkable compositions 1a3 (photoinitiator B1) and 2a3 (photoinitiator B2) of the present invention provide specimens with satisfactory mechanical properties, the same as those obtained from the comparative composition C1a3 (TPO-L).

[0921] It can also be seen that, different from the comparative specimens, the specimens obtained according to the method of the present invention do not have a sense of stickiness.

[0922] Example 5: Photoinitiation of the present invention at 405 nm at very low energies (1.5 mW / cm 2 to 3.8 mW / cm 2 ) Evaluation of the crosslinking depth of the agent

[0923] Example 5a :

[0924] Table 8: Summary table of photocrosslinkable compositions used:

[0925]

[0926] The molar amount of phosphorus atoms present in the photocrosslinkable composition enables an approximate estimation of the amount of active substance material in the photocrosslinkable composition under study.

[0927] Therefore, it should be noted that the photocrosslinkable composition of the present invention in Example 5 has a small amount of active substance material compared with the comparative composition C1a3.

[0928] In the context of this example, the organopolysiloxane A used in different photocrosslinkable compositions is polymer a3. This example shows the activity of photoinitiators B2 and B3 defined in the present invention at a wavelength of 405 nm, and thus the activity at very low energy.

[0929] The 3D printer used is a UV-LED (Anycubic Photon Mono6k) at 405 nm; the first layer is irradiated for 80 s, and each of the subsequent other layers is irradiated for 20 s to obtain specimens.

[0930] Table 9: With the energy used (1.5 mW / cm 2 、2.6 mW / cm 2or 3.8 mW / cm 2 ) Measurement of the crosslinking depth values of different compositions that vary.

[0931]

[0932] These tests clearly demonstrate the activity of the photocrosslinkable compositions of the present invention at very low energies and very low molar concentrations of photoinitiator.

[0933] Example 6: Research on the mechanical properties of the specimen formulation 3D printed with filler :

[0934] In the context of this example, the organopolysiloxane A used in different photocrosslinkable compositions is a combination of polymers a1 and a3.

[0935] This example aims to measure the mechanical properties of specimens containing 22% to 30% of filler D1 according to the method of the present invention. The formulations prepared under the conditions in Table 10 below are placed in an Asiga 3D printer equipped with a UV-LED with a wavelength of 385 nm.

[0936] At an energy of 11 mW / cm 2 3D printed specimens of the formulations listed below are produced in this example. The 3D specimens are printed with 27 layers, each layer 75 microns thick.

[0937] Table 10: Summary table of different photocrosslinkable compositions used:

[0938]

[0939] Measure the viscosity of the formulations containing 22% to 30% silica shown in the table above according to the protocol described below.

[0940] After manually mixing these formulations for 5 minutes and allowing them to stand for at least one hour, measure the viscosity of these formulations using a Brookfield Cap 2000 cone-plate viscometer (cone 6), as described in Table 11 below.

[0941] Table 11: Measurement of the viscosity of different formulations produced:

[0942]

[0943] The comparative formulation C1a1 + a3 containing 22% to 30% of filler D1 has a high viscosity at low shear rates (<20 s -1 ), and this makes it impossible to produce specimens by 3D printing under these conditions. This is because the ASIGA-DLP printer uses a dedicated tank (SG-MAX-TRAY-1L-LF, suitable for low shear rates <20 s -1For a low peel force (for high viscosities), the maximum viscosity accepted is 15,000 mPa.s.

[0944] This mismatch (inadéquation) also exists in other additive manufacturing techniques, such as stereolithography (SLA) printing, continuous liquid interface production printing (CLIP), or printing via a liquid crystal display (LCD).

[0945] On the other hand, formulations 2a1 + a3 and 3a1 + a3 of the invention comprising photoinitiators B2 and B3 are compatible with the manufacture of specimens by 3D printing at high filler values (e.g., 25% or even 30% by mass of filler D1 relative to the total mass of the formulation).

[0946] The following table mentions the mechanical and physical properties such as elongation at break, breaking strength, elastic modulus at 100%, hardness, and stickiness sensation of specimens produced from specimens containing 22%, 25%, or 30% of filler D1 at an energy of 11 mW / cm 2 .

[0947] Table 12: Table of mechanical properties related to these formulations:

[0948]

[0949] The acronym "N.A." mentioned in the above table means that this does not apply to the comparative specimen C1a1 + a3. In fact, the high viscosity of the comparative formulation 0a1 + a3 does not allow the additive manufacturing of specimens.

[0950] On the contrary, the formulations defined according to the method of the invention make it possible to obtain 3D - printed specimens with satisfactory mechanical properties, as demonstrated by the data in Table 12 above.

[0951] Moreover, it can be seen that the presence of the filler makes it possible to significantly improve the mechanical and physical properties of the specimens obtained according to the method of the invention.

[0952] In particular, it can be seen that starting from 30% of filler D1, the specimens obtained according to the method of the invention have improved tear strength properties compared to other specimens.

[0953] This mechanical property is satisfactory, thus allowing new application fields to be considered for the 3D printing of such formulations and functional objects obtained according to the method of the invention.

[0954] Finally, it can also be seen that, unlike the comparative specimens, the specimens obtained according to the method of the invention do not have a stickiness sensation.

[0955] Example 7: Research on the mechanical properties of the tensile specimen formulation 3D printed with filler at very low energy (405 nm) formulation :

[0956] In the context of the present example, formulation 2a1 + a3 (containing 30% filler D1) as defined in Table 7 was studied at 3.8 mW / cm 2 . The present example aims to disclose that at a wavelength of 405 nm, the method according to the invention is capable of providing specimens with satisfactory mechanical properties.

[0957] In the context of the present example, at a wavelength of 405 nm and an energy of 3.8 mW / cm 2 , the first layer of the specimen was irradiated for 20 s, and each subsequent layer was irradiated for 5 s.

[0958] The following table shows the mechanical properties of the specimens obtained according to the method of the invention at an energy of 3.8 mW / cm 2 .

[0959] Table 13: Mechanical properties of specimens obtained according to the method of the invention at an energy of 3.8 mW / cm 2

[0960]

[0961] It should be recalled that the comparative formulation C1a1 + a3 with 30% filler D1 had a high viscosity and did not allow the additive manufacturing of the samples.

[0962] On the other hand, it can be concluded that at 3.8 mW / cm 2 and a high filler D1 value (30%), the mechanical properties of the specimens obtained according to the method of the invention are satisfactory.

[0963] Example 8: Measurement of the "yellowing" effect of the specimen obtained according to the method of the invention

[0964] Table 14: Measurement of the "yellowing" effect of specimens obtained according to the method of the invention

[0965]

[0966] The different photocrosslinkable compositions mentioned in the above table have a photoinitiator mass percentage of 1% relative to the total mass of the photocrosslinkable composition. In the context of the present example, the "yellowing" effect of the specimens obtained according to the method of the invention was studied. The specimens obtained according to the method of the invention were compared with specimens obtained from the comparative photocrosslinkable composition C1a2 having satisfactory "photo-bleaching" properties.

[0967] For this purpose, the CIELAB standard test was carried out to evaluate the "yellowing" effect of these different specimens.

[0968] The above table mentions the values of the L, a, and b amounts of the different specimens obtained from the photocrosslinkable composition.

[0969] These values correspond to the different XYZ axes presented in Figure 1 the attachment.

[0970] Thus, it can be seen that, according to the method of the present invention, the specimens obtained from the photocrosslinkable composition 2a2 have similar amounts of L, a, and b to those of the comparative photocrosslinkable composition C1a2.

[0971] Therefore, it can be concluded that the photocrosslinkable composition 2a2 of the present invention has satisfactory "photobleaching" properties.

[0972] Example 9: Test on the carrier coated with an anti-sticking silicone coating:

[0973] In this example, the photocrosslinkable composition Inv1 is formed from a mixture of polymer a4 and polymer a5 and a photoinitiator B3 in an amount of 0.8% by mass based on the total mass of the photocrosslinkable compositions in the following examples.

[0974] Similarly, the comparative composition Comp1 is formed from a mixture of polymer a4 and polymer a5 and a photoinitiator C1 in an amount of 0.8% by mass based on the total mass of the photocrosslinkable composition.

[0975] These two compositions were studied at 11.5 mW / cm 2 .

[0976] Tests were carried out on a carrier coated with an anti - sticking silicone coating:

[0977] Smear: Qualitative testing of surface polymerization by the finger - mark method, which consists of:

[0978] - Placing a sample of the silicone - coated carrier to be tested on a flat rigid surface;

[0979] - Making a mark with the tip of the finger by pressing moderately but distinctly; and

[0980] - Examining the mark thus made by eye, preferably in light close to the surface. Thus, the presence of even very slight marks can be seen by the difference in surface gloss.

[0981] The evaluation is qualitative. The "smear" is quantified using the following grades:

[0982] A: Very good, no finger marks

[0983] B: Slightly less good, marks hardly visible

[0984] C: Clear marks

[0985] D: Very clear marks on the surface and an oily appearance, the product hardly polymerizes.

[0986] That is to say, the grades from A to D are from the best result to the worst result. Rub-off: To test the ability of the silicone to adhere to the flexible carrier by rubbing back and forth with a finger (gommage), which consists in

[0987] - Placing the sample of the silicone-coated carrier to be tested on a flat rigid surface, with the silicone on the upper surface.

[0988] - Pressing moderately but firmly with the tip of the finger and rubbing back and forth (A-R) 10 times (over a length of approximately 10 cm).

[0989] - Checking by eye for the appearance of the gommage. The gommage corresponds to the appearance of a fine white powder or small balls rolling under the finger.

[0990] The evaluation is qualitative. The "rub-off" is quantified with the following grades:

[0991] · 10: Very good, no appearance of gommage after 10 back-and-forth rubs

[0992] · 1: Very poor, appearance of gommage from the first back-and-forth motion.

[0993] This grade corresponds to the number of back-and-forth rubs (from 1 to 10) from which the gommage starts to appear.

[0994] That is to say, the grades from 1 to 10 are from the worst result to the best result. Demouillage: Using an ink with a standardized surface tension, the degree of polymerization of the silicone layer is evaluated by assessing the transfer of the silicone onto the adhesive in contact with the coating. The method is as follows:

[0995] - Selecting a sample of silicone-coated paper approximately 20 × 5 cm obtained in the unwind direction (machine direction) to be characterized.

[0996] - Cutting a piece of tape approximately 15 cm in length, then placing it on the adhesive side of the paper to be tested without folding, while applying pressure 10 times by sliding a finger along the length of the tape ("Scotch" 3M tape, reference 610, width: 25 mm).

[0997] - Removing the tape and laying it flat, with the adhesive-treated part facing up.

[0998] - Using a (disposable) cotton swab to deposit an ink mark approximately 10 cm in length on the adhesive-treated part of the tape (ink with the trademark SHERMAN or FERARINI and BENELI, surface tension ≈ 30 dynes / cm and viscosity 2 - 4 mPa / s). Immediately start the timer.

[0999] - When the appearance of the ink line changes, it is considered that the anti-wetting phenomenon stage has been entered, and thus the timer is stopped.

[1000] - The deposition of the ink on the adhesive-treated part of the tape must be carried out within 2 minutes after the silicone coating.

[1001] - If the resulting value is < 10 seconds, it is considered that there is migration of silicone on the adhesive and the polymerization is incomplete.

[1002] - A rating from 0 to 10 will be given, corresponding to the time elapsed in seconds before the anti-wetting phenomenon is observed.

[1003] - If the resulting value is 10 seconds, it is considered that the polymerization is complete. In this case, a rating of 10 will be given, indicating a very good result.

[1004] - Record the obtained rating and the ink used (name, trademark, surface tension, viscosity).

[1005] Extractables: Measure the amount of silicone that is not grafted to the network formed during the polymerization. These silicones are extracted from the film by immersing the sample in MIBK for at least 24 hours when the sample leaves the machine. This is measured by flame absorption spectroscopy. The ratio of extractables should be kept below 8%, preferably below 6%. The results of different test items are shown in the following table.

[1006] Table 15: Results of test items for the coating

[1007] formulation <![CDATA[Comp1]]> <![CDATA[Inv1]]> <![CDATA[Sediment (g / m 2 )(0.85 ± 0.05)]]> 0.83 0.88 Apply A A Erase 10 10 Anti-wetting 10 10 <![CDATA[Online extractable matter (100 cm 2 )%]]> 5.8 5.2

[1008] The test items of the formulation containing the photoinitiator B3 of the present invention are satisfactory. The performance of the obtained coating has not deteriorated.

[1009] Release: Measurement of the release force is carried out on a carrier coated with a silicone coating using a standardized adhesive TESA 7475. A specimen of the multi-layer article (the adhesive in contact with the silicone surface) is stored under the required pressure conditions: 1 day at 23 °C (FINAT 3 - FTM 3), 1 day at 70 °C (FINAT 10 - FTM 10), and 7 days at 40 °C, and then tested at a low release speed according to the above-mentioned tests known to those skilled in the art.

[1010] The release force is expressed in cN / inch and is measured using a dynamometer at ambient temperature (23 °C) when the sample is placed under pressure or at a higher temperature for accelerated aging tests.

[1011] The results are presented in Table 16 below.

[1012] Table 16: Peel force expressed in cN / inch

[1013]

[1014] The peel force obtained with the formulations of the invention was observed to be satisfactory, especially after ageing.

[1015] Subsequent adhesion (adhésion subséquente or "Subsequent adhesion" in English) (designated "SubAd" in the table): Verification measurement of the retention of the adhesion of an adhesive (TESA 7475) that has been in contact with a silicone coating, according to the FINAT 11 test (FTM 11) known to those skilled in the art. In this case, the reference specimen is PET and the adhesive remains in contact with the silicone surface to be tested for 7 days at 40 °C.

[1016] The results are expressed as the percentage of the adhesion retention of the reference tape: CA = (Fm2 / Fm1) × 100, expressed as a percentage

[1017] where:

[1018] Fm2 = average tape peel force after 20 hours of contact with the silicone-treated carrier;

[1019] Fm1 = average tape peel force without contact with the silicone-treated carrier.

[1020] The results are recorded in Table 17 below.

[1021] Table 17: Subsequent adhesion (%)

[1022] formulation <![CDATA[Comp1]]> <![CDATA[Inv1]]> 7d@40℃ 100 100

[1023] Thus, in the case of using the formulations of the invention, the measurement of subsequent adhesion is very satisfactory, even after ageing. In fact, there is no loss of adhesion of the adhesive in contact with the silicone coating.

Claims

1. An additive manufacturing method for producing silicone elastomer products, the method comprising the following steps: i) Using a photocrosslinkable silicone composition X and an irradiation source, the photocrosslinkable silicone composition X comprising: a) at least one organopolysiloxane A containing at least one (meth)acrylate group b) at least one free radical photoinitiator B represented by formula (I): Wherein, R represents linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene, said alkylene and heteroalkylene containing at least one siloxane functional group; R1 represents a group of formula (II): Where Ar represents an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - an alkyl group having 1 - 6 carbon atoms, - an alkenyl group having 2 - 4 carbon atoms, - a heteroatom O, N or S, - a halogen, - a SiMe3 group, - a hydroxyl group (OH), - a (O - Alk) group, wherein Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5; R2 represents: - the group R1, - an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - an alkyl group having 1 - 6 carbon atoms, - an alkenyl group having 2 - 4 carbon atoms, - a heteroatom O, N or S, - a halogen, - a SiMe3 group, - a hydroxyl group (OH), - a (O - Alk) group, wherein Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5; ii) Selectively irradiating at least a part of the photocrosslinkable silicone composition X with the irradiation source for forming a part of the silicone elastomer article; and iii) Repeating step ii) a number of times sufficient to produce the silicone elastomer article.

2. The method according to claim 1, wherein the free radical photoinitiator B is a compound of formula (VIII): Wherein: R1 and R2 represent the groups as defined in claim 1; R3 represents a linear or branched C1 - C6 alkylene or heteroalkylene; R4 represents a linear or branched C1-C 50 alkylene or heteroalkylene, preferably a linear or branched C1-C 18 alkylene or heteroalkylene, wherein R4 comprises at least one siloxane functional group.

3. The method according to any one of the preceding claims, wherein the free radical photoinitiator B is a compound of formula (XIII): wherein, R5, which may be the same or different, represents: - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, - an aryl group containing 6 - 10 carbon atoms, preferably phenyl, - an alkenyl group containing 2 - 6 carbon atoms, preferably vinyl, - an acrylate or methacrylate group, - a hydroxyl group (OH), - a (O - Alk) group, wherein Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably CH3 or C2H5, -(O-Alk) x a group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200 - a linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, for example (C1 - C5)alkyl - CF3, and the alkyl is linear or branched, - hydrogen, - a group of formula (XIV): Where R1 and R2 represent the groups as defined in claim 1, R6 represents linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene; a represents an integer from 0 to 100; The method is characterized in that at least one group R5 is represented by a group of formula (XIV).

4. The method according to any one of the preceding claims, wherein the free radical photoinitiator B is a compound of formula (XV): R7, which are the same or different, represent: - an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably methyl, - an aryl group containing 6-10 carbon atoms, preferably phenyl, - an alkenyl group containing 2-6 carbon atoms, preferably vinyl, - hydroxyl (OH), - a (O-Alk) group, wherein Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5, - a (O-Alk) x group, wherein Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200, - an acrylate or methacrylate group, - a linear or branched alkyl group containing 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 to 10 fluorine atoms, such as (C1-C5) alkyl-CF3, and the alkyl group is linear or branched, - hydrogen, R8 represents a group defined for R7 or a group of formula (XVI): wherein R1 and R2 represent groups as defined in claim 1, R6 represents a linear or branched C1-C 50 alkylene or heteroalkylene group, preferably a linear or branched C1-C 18 alkylene or heteroalkylene group; a represents an integer from 0 to 10; b represents an integer from 1 to 100; The method is characterized in that at least one group R8 is represented by a group of formula (XVI).

5. The method according to any one of the preceding claims, wherein the free radical photoinitiator B is a compound of formula (XVII): wherein, R9, which may be the same or different, represents: - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, preferably 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, preferably methyl, - an aryl group having 6 to 10 carbon atoms, preferably a phenyl group, - an alkenyl group having 2 to 6 carbon atoms, preferably a vinyl group, - hydroxy (OH), - an (O-Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5, -(O-Alk) x a group, wherein Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200 - an acrylate or methacrylate group, - a linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, such as 1 to 10 fluorine atoms, for example (C1-C5) alkyl-CF3, and the alkyl is linear or branched, - an amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group having 1 to 5 carbon atoms, - a carbonyl or carboxyl group, - hydrogen, - a group of formula (XVIII): where R1 and R2 represent groups as defined in claim 1, R6 represents linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene; R 10 , identical or different, representing: - an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, - an aryl group having 6 to 10 carbon atoms, preferably a phenyl group, - an alkenyl group having 2 to 6 carbon atoms, preferably a vinyl group, - hydroxy (OH), - an (O-Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5, -(O-Alk) x a group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200 - an acrylate or methacrylate group, - a linear or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which is substituted by at least one fluorine atom, such as 1 to 10 fluorine atoms, for example (C1-C5) alkyl-CF3, and the alkyl is linear or branched, - an amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group having 1 to 5 carbon atoms, - a carbonyl or carboxyl group, - hydrogen, R 11 represents the group -CH3 or an oxygen atom; Z represents the group -CH2- or an oxygen atom; Ar represents an aryl group having 6 to 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - an alkyl group having 1 to 6 carbon atoms, - an alkenyl group having 2 to 4 carbon atoms, - a heteroatom O, N or S, - a halogen, - a SiMe3 group, - hydroxy (OH), - an (O-Alk) group, where Alk represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably CH3 or C2H5; m represents a natural integer from 1 to 8; p represents a natural integer equal to 0 or 1; q represents a natural integer from 0 to 100; a represents a natural integer equal to 1 or 2; b represents a natural integer from 0 to 100.

6. The method according to any one of the preceding claims, wherein the free radical photoinitiator B and the organopolysiloxane A are the same molecule, denoted as AB.

7. The method according to any one of the preceding claims, wherein the compound AB is a compound of formula (XXa), (XXb), (XXc) or (XXd): wherein R 12 , which are the same or different, represent a hydrogen atom or a hydroxyl group; R 13 , which are the same or different, represent: - an alkenyl functional group having 2 to 4 carbon atoms, - a group of formula (XXI): and at least one group R 13 represents a group of formula (XXI), and R1 and R2 represent the groups as defined in claim 1; R14 express; Alkyl groups of 1 to 5 carbon atoms or alkenyl groups of 2 to 5 carbon atoms: - is substituted or unsubstituted by at least one heteroatom O, N or S, - substituted or unsubstituted by at least one alkyl group having 1 to 5 carbon atoms, - may be substituted or unsubstituted by at least one aromatic group having 6 to 18 carbon atoms, -x1 is an integer from 1 to 1000; preferably x1 is from 1 to 500; - n1 is an integer from 1 to 100, preferably n1 is from 2 to 50; -x2 is an integer from 1 to 1000, preferably x2 is from 1 to 500; - n2 is an integer from 0 to 100, preferably n2 is from 0 to 50; - x3 is an integer from 1 to 1000, preferably x3 is from 1 to 500; and - n3 is an integer from 0 to 100, preferably n3 is from 0 to 50 - x4 is an integer from 1 to 1000, preferably x3 is from 1 to 500; and - n4 is an integer from 0 to 100, preferably n3 is 0 to 50; - m1, m2, m3 and m4 are integers from 1 to 8.

8. The method according to any one of the preceding claims, characterized in that The photocrosslinkable composition X further comprises a filler D.

9. The method according to any one of the preceding claims, characterized in that The photocrosslinkable composition X further comprises a light absorber E or a light stabilizer F and mixtures thereof.

10. The method according to any one of the preceding claims, characterized in that The weight-average molecular weight of the free radical photoinitiator B is 400 - 10,000 g / mol, preferably 400 - 5,000, more preferably 400 - 3,000, and even more preferably 400 - 2,600 g / mol.

11. The method according to any one of the preceding claims, characterized in that The mass percentage of the free radical photoinitiator B, based on the total mass of the photocrosslinkable composition X, is 0.1 - 20%, preferably 0.1 - 5% based on the total mass of the photocrosslinkable composition X, more preferably 0.2 - 2%, and even more preferably 0.4 - 1.5%.

12. The method according to any one of the preceding claims, characterized in that Additive manufacturing is a technique selected from the following: printing by stereolithography (SLA), by digital light processing (DLP), by liquid crystal display (LCD), and by continuous liquid interface production (CLIP).

13. A photo-crosslinkable silicone composition X2 comprising: - 10 to 99.9% by mass of at least one organopolysiloxane A comprising at least one (meth)acrylate group; - 0.1-20% by mass of at least one free radical photoinitiator B, which is a compound of formula (I): in, R represents linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene, said alkylene and heteroalkylene containing at least one siloxane functional group; R1 represents a group of formula (II): wherein Ar represents an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - an alkyl group having 1 - 6 carbon atoms, - an alkenyl group having 2 - 4 carbon atoms, - a heteroatom O, N, or S, - a halogen, - a SiMe3 group, - a hydroxyl group (OH), - an (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, more preferably 1 - 10 carbon atoms, even more preferably 1 - 5 carbon atoms, preferably CH3 or C2H5; R2 represents: - a group R1, - an aryl group having 6 - 18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - an alkyl group having 1 - 6 carbon atoms, - an alkenyl group having 2 - 4 carbon atoms, - a heteroatom O, N, or S, - a halogen, - a SiMe3 group, - a hydroxyl group (OH), - an (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, more preferably 1 - 10 carbon atoms, even more preferably 1 - 5 carbon atoms, preferably CH3 or C2H5.

14. A method for preparing a coating on a carrier, comprising the following steps: - applying the photocrosslinkable silicone composition X2 to a carrier, and - crosslinking the composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation having a wavelength of 200 nm - 450 nm, especially UV radiation.

15. A photoinitiator of formula (XXVIII) Wherein: R9, which may be the same or different, represents: - an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, more preferably 1 - 10 carbon atoms, even more preferably 1 - 5 carbon atoms, preferably methyl, - an aryl group containing 6 - 10 carbon atoms, preferably phenyl, - an alkenyl group containing 2 - 6 carbon atoms, preferably vinyl, - a hydroxyl group (OH), - an (O - Alk) group, where Alk represents an alkyl group containing 1 - 15 carbon atoms, preferably 1 - 12 carbon atoms, more preferably 1 - 10 carbon atoms, even more preferably 1 - 5 carbon atoms, preferably CH3 or C2H5, -(O-Alk) x a group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200 - an acrylate or methacrylate group, - a linear or branched alkyl group containing 1 - 10 carbon atoms, preferably 1 - 5 carbon atoms, which is substituted by at least one fluorine atom, for example 1 - 10 fluorine atoms, for example (C1 - C5) alkyl - CF3, where the alkyl is linear or branched, - An amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group containing 1-5 carbon atoms, - A carbonyl or carboxyl group, - Hydrogen, - A group of formula (XXIX): where R1 and R2 represent groups as defined according to claim 1, R6 represents linear or branched C1-C 50 alkylene or heteroalkylene, preferably linear or branched C1-C 18 alkylene or heteroalkylene; R 10 , same or different, represent: - An alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably methyl, - An aryl group containing 6-10 carbon atoms, preferably phenyl, - An alkenyl group containing 2-6 carbon atoms, preferably vinyl, - Hydroxyl (OH), - A (O-Alk) group, where Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5, -(O-Alk) x a group, where Alk represents an alkyl group containing 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, preferably methyl, and x represents an integer from 2 to 200 - An acrylate or methacrylate group, - A linear or branched alkyl group containing 1-10 carbon atoms, preferably 1-5 carbon atoms, which is substituted by at least one fluorine atom, such as 1-10 fluorine atoms, such as (C1-C5) alkyl-CF3, and the alkyl is linear or branched, - An amino group selected from (Alk)-NH2 or (Alk)-NH-(Alk)-NH2, where Alk represents an alkyl group containing 1-5 carbon atoms, - A carbonyl or carboxyl group, - Hydrogen, R 11 represents the group -CH3 or an oxygen atom; Z represents the group -CH2- or an oxygen atom; Ar represents an aryl group of 6-18 carbon atoms, which is substituted or unsubstituted by at least one of the following groups: - An alkyl group of 1-6 carbon atoms, - An alkenyl group of 2-4 carbon atoms, - A heteroatom O, N or S, - A halogen, - A SiMe3 group, - Hydroxyl (OH), - A (O-Alk) group, where Alk represents an alkyl group containing 1-15 carbon atoms, preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, preferably 1-5 carbon atoms, preferably CH3 or C2H5; m represents a natural integer from 1-8; p represents a natural integer equal to 0 or 1; q represents a natural integer from 0-100; a represents a natural integer equal to 1 or 2; b represents a natural integer from 0-100; The photoinitiator is characterized in that when a = 1, q > 0 or at least one group R9 is a hydroxyl group.

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