Additive manufacturing method for preparing silicone elastomer articles

Abstract

An additive manufacturing method for preparing silicone elastomer articles is provided. In particular, the present invention relates to an additive manufacturing method for preparing silicone elastomers from a photocrosslinkable silicone composition. The present invention also relates to a photocrosslinkable silicone composition.

Description

Technical Field

[0001] The present invention relates to an additive manufacturing method for producing silicone elastomer articles. In particular, the present invention relates to an additive manufacturing method for producing silicone elastomers from a photocrosslinkable silicone composition. The present invention also relates to a photocrosslinkable silicone composition. Background Art

[0002] Additive manufacturing processes are gaining increasing importance and have an incredible growth potential due to numerous possible commercial applications. To make their use widespread, it is necessary to broaden the range of materials that can be used in additive manufacturing machines.

[0003] In particular, silicone as a printing material is one of the most promising materials for additive manufacturing due to its many advantages, including flexibility, biocompatibility, insulation properties for electrical and electronic components, and good chemical resistance, temperature resistance, and weathering resistance.

[0004] Among additive manufacturing technologies, photopolymerization (photocuring) can be performed in a tank. This technique enables the fabrication of objects in successive layers, with each layer representing a cross-section of the object to be manufactured. It is based on the use of a radiation source that selectively crosslinks a photocrosslinkable composition in a tank at the desired locations. This composition then cures to form a thin crosslinked layer, and the object can be manufactured by stacking more than one crosslinked layer.

[0005] Photopolymerization in a tank can be performed using a variety of processes, such as laser stereolithography (SLA) printing, digital light processing (DLP) 3D printing, and continuous liquid interface production (CLIP).

[0006] The SLA process is based on the use of a laser as a radiation source. The laser is focused on the surface of a photocrosslinkable composition and traces the cross-section of the 3D object. Typically, two motors called galvanometers, one on the x-axis and the other on the y-axis, operate at high speed to direct the laser beam onto the print area, thereby solidifying the composition. In this process, the object is broken down layer by layer into a series of dots and lines. This technology is described, for example, in WO 2015 / 197495.

[0007] In the DLP process, a digital screen projector projects a single image of each layer onto the entire surface of a photocrosslinkable composition. Because the projector has a digital screen, the image of each layer is a set of square pixels, and each layer is then composed of small rectangular bricks called voxels. For example, this technology is described in document WO2016 / 181149. The DLP process can make some parts print faster because each layer is exposed all at once, rather than being drawn with a laser. Although faster than the SLA process, the DLP process involves a trade-off between resolution and surface finish quality, whether printing large parts or printing more than one smaller part with many details.

[0008] In recent years, another in-tank photopolymerization technology has been developed: continuous liquid interface production (CLIP). This technology is also based on the selective crosslinking of a photocrosslinkable composition using a radiation source. However, unlike the previous two technologies, the CLIP process is performed layer by layer, but continuously, due to the persistent presence of a liquid interface. Therefore, CLIP allows for faster printing compared to SLA or DLP processes. For example, this technology is described in WO2014 / 126837.

[0009] US 2017 / 0312729 describes a photopolymerization method using a liquid silicone composition that can be photocrosslinked into an elastomer in a can. The composition comprises an alkenyl-containing siloxane, a hydride-containing siloxane, and a photoactivated catalyst. This composition crosslinks via an addition-based polyaddition reaction. However, this polyaddition-based technology suffers from the fact that the reaction catalysis is not instantaneous, and the product typically requires a post-curing step, i.e., a post-treatment heating step.

[0010] Other types of silicone compositions can be crosslinked to form elastomers. WO 2003 / 016403 describes photocrosslinkable silicone compositions containing acrylate functionalities. However, these compositions are not compatible with all conventional crosslinking methods, as the reaction is inhibited by oxygen in the ambient air.

[0011] "Dual-cure" silicone elastomer compositions containing chemical functional groups that allow crosslinking by both UV light and humidity have also been described in the literature, for example, in US Pat. No. 7,105,584. However, these dual-cure compositions have difficulty achieving deep crosslinking, and the volatile products produced by humidity crosslinking limit their application. Consequently, their realization in pot photopolymerization processes is more challenging.

[0012] Therefore, there is a need to provide an improved tank photopolymerization process for preparing silicone elastomer articles.

[0013] Technical issues

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

[0015] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomer articles.

[0016] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank.

[0017] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank, which method does not require a post-curing step.

[0018] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomer articles, which is easy to implement.

[0019] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomer articles with good elastomeric and mechanical properties.

[0020] One of the basic objects of the present invention is to provide an additive manufacturing method for preparing silicone elastomers from photocrosslinkable silicone compositions.

[0021] One of the basic objects of the present invention is to provide a photocrosslinkable silicone composition in a silicone elastomer. Summary of the Invention

[0022] The present invention first relates to an additive manufacturing method for preparing a silicone elastomer article, the method comprising the following steps:

[0023] i. Implementing a photocrosslinkable silicone composition Y and a radiation source, the photocrosslinkable silicone composition Y comprising:

[0024] a. at least one linear organopolysiloxane A having the general formula (I)

[0025] [Chemical Formula 1]

[0026]

[0027] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0028] E is a group comprising a cationically polymerizable and / or crosslinkable functional group, preferably an epoxy functional group or a vinyl oxide functional group, wherein the cationically polymerizable and / or crosslinkable functional group is attached to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally one or more heteroatoms, preferably oxygen;

[0029] Each group X is independently R 1 or E;

[0030] a+b≥150; preferably 2000≥a+b≥150;

[0031] The organopolysiloxane A has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups; the molar content of the cationically polymerizable and / or crosslinkable functional groups in the organopolysiloxane A is less than or equal to 18 mmol / 100 g of the organopolysiloxane A, preferably less than or equal to 15 mmol / 100 g of the organopolysiloxane A;

[0032] b. Optionally, at least one linear organopolysiloxane B of the general formula (I), wherein

[0033] a+b≤100; preferably 1≤a+b≤100;

[0034] The organopolysiloxane B has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups, preferably epoxy functional groups or vinyl oxide functional groups; and

[0035] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of organopolysiloxane B;

[0036] c. at least one cationic photoinitiator C;

[0037] d. Optionally, filler D,

[0038] e. Optionally, a photosensitizer E, and

[0039] f. Optionally, a light absorber F,

[0040] ii. selectively irradiating at least a portion of the photocrosslinkable silicone composition Y using a radiation source to form a portion of a silicone elastomer article; and

[0041] iii. Repeat step ii) a sufficient number of times to prepare a silicone elastomer article.

[0042] The presence of a long-chain linear organopolysiloxane A, i.e., having at least 150 siloxane units and a low molar content of cationically polymerizable and / or crosslinkable functional groups, enables the production of silicone elastomeric articles by photopolymerization in a tank. The linear organopolysiloxane A allows good elastomeric properties, in particular a high elongation at break, to be achieved.

[0043] Furthermore, this additive manufacturing method is easy to implement and does not require any post-curing steps, i.e., no post-processing heating steps are required.

[0044] The invention also relates to an article made of silicone elastomer obtained by the process described herein.

[0045] The present invention also relates to a photocrosslinkable silicone composition Y' comprising:

[0046] a. at least 75% by weight of a linear organopolysiloxane having the general formula (I) A'

[0047] [Chemical Formula 2]

[0048]

[0049] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0050] E is a group comprising a cationically polymerizable and / or crosslinkable functional group, preferably an epoxy functional group or a vinyl oxide functional group, wherein the cationically polymerizable and / or crosslinkable functional group is attached to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally one or more heteroatoms, preferably oxygen;

[0051] Each group X is independently R 1 or E;

[0052] a+b≥200; preferably 2000≥a+b≥200;

[0053] The organopolysiloxane A' has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups; the molar content of the cationically polymerizable and / or crosslinkable functional groups in the organopolysiloxane A' is less than or equal to 18 mmol / 100 g of the organopolysiloxane A', preferably less than or equal to 15 mmol / 100 g of the organopolysiloxane A';

[0054] b. 1 to 20% by weight of a linear organopolysiloxane B' of the general formula (I), wherein

[0055] a+b≤150; preferably 1≤a+b≤100;

[0056] The organopolysiloxane B' has at least two groups E comprising cationically polymerizable and / or crosslinkable functional groups, preferably epoxy functional groups or vinyl oxide functional groups; and

[0057] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B' is greater than or equal to 20 mmol / 100 g of the organopolysiloxane B';

[0058] c. at least one cationic photoinitiator C;

[0059] The present invention also relates to the use of the photocrosslinkable silicone composition Y' for additive manufacturing of silicone elastomer articles.

[0060] Finally, the invention also relates to silicone elastomers obtainable by crosslinking a photocrosslinkable silicone composition Y′. DETAILED DESCRIPTION

[0061] Additive manufacturing method for preparing silicone elastomer articles

[0062] Firstly, the present invention relates to an additive manufacturing method for preparing a silicone elastomer article, the method comprising the following steps:

[0063] i. Implementing a photocrosslinkable silicone composition Y and a radiation source, the photocrosslinkable silicone composition Y comprising:

[0064] a. At least one linear organopolysiloxane A of formula (I)

[0065] [Chemical Formula 3]

[0066]

[0067] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0068] E is a group comprising a cationically polymerizable and / or crosslinkable functional group, preferably an epoxy functional group or a vinyl oxide functional group, wherein the cationically polymerizable and / or crosslinkable functional group is attached to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen;

[0069] Each group X is independently R 1 or E;

[0070] a+b≥150; preferably 2000≥a+b≥150;

[0071] The organopolysiloxane A has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups;

[0072] The molar content of the cationic polymerization and / or crosslinking functional groups of the organopolysiloxane A is less than or equal to 18 mmol / 100 g of organopolysiloxane A, preferably less than or equal to 15 mmol / 100 g of organopolysiloxane A;

[0073] b. Optionally, at least one linear organopolysiloxane B of the general formula (I), wherein

[0074] a+b≤100; preferably 1≤a+b≤100;

[0075] The organopolysiloxane B has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups, wherein the cationically polymerizable and / or crosslinkable functional groups are preferably epoxy functional groups or vinyl oxide functional groups; and

[0076] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of organopolysiloxane B;

[0077] c. at least one cationic photoinitiator C;

[0078] d. Optionally, filler D,

[0079] e. Optionally, a photosensitizer E, and

[0080] f. Optionally, a light absorber F,

[0081] ii. selectively irradiating at least a portion of the photocrosslinkable silicone composition Y using a radiation source to form a portion of a silicone elastomer article; and

[0082] iii. Repeat step ii) a sufficient number of times to prepare a silicone elastomer article.

[0083] In general, all additive manufacturing methods share a common starting point: a computer data source or computer program that describes the object. This computer data source or computer program can be based on a real or virtual object. For example, a real object can be scanned using a 3D scanner, and the resulting data can be used to generate the computer data source or computer program. Alternatively, the computer data source or computer program can be designed from scratch.

[0084] A computer data source or computer program is typically converted into a stereolithography (STL) format file, although other file formats can also be used. This file is typically read by 3D printing software, which uses this file and optional user input to divide the object into hundreds, thousands, or even millions of "layers." Typically, the 3D printing software transmits instructions to the machine, such as in the form of G-code, which is read by the 3D printer and then typically produces the object layer by layer.

[0085] Advantageously, the additive manufacturing method is a photopolymerization method in a tank, in particular by laser stereolithography (SLA) printing, digital light processing (DLP), or continuous liquid interface preparation (or CLIP). These techniques and the associated equipment are well known to those skilled in the art, who will know how to select the appropriate technology and the corresponding 3D printer. These techniques and equipment are described in the following documents: WO2015 / 197495, US5236637, WO2016 / 181149, and WO2014 / 126837.

[0086] The radiation source can be any radiation source that allows photocrosslinking of the photocrosslinkable silicone composition Y. Advantageously, the radiation source is a light source, preferably an ultraviolet (UV) light source, a visible light source or an infrared (IR) light source. Typically, the wavelength of the ultraviolet light source is 200nm to 400nm, the wavelength of the visible light source is 400nm to 700nm, and the wavelength of the infrared light source is greater than 700nm, such as 700nm to 1mm, or 700nm to 10000nm. The light source can be a lamp or a laser. Preferably, the radiation source is selected from an ultraviolet lamp, an ultraviolet laser, a visible light lamp, a visible light laser, an infrared lamp and an infrared laser. Among the usable radiation sources, the mercury lamp commonly used in the photopolymerization reaction of silicone compositions can be mentioned. In a specific embodiment of the present method, the radiation source is an LED lamp, preferably an LED lamp with a wavelength of 355nm, 365nm, 385nm or 405nm.

[0087] The power of the radiation source may be at least 1 mW / cm 2 , at least 10mW / cm 2 or at least 50mW / cm 2 The power of the radiation source can be 1mW / cm 2 Up to 1000mW / cm 2, preferably 10 mW / cm 2 Up to 500mW / cm 2 , more preferably 50 mW / cm 2 Up to 200mW / cm 2 .

[0088] In certain embodiments, the radiation penetration depth (Dp) is less than 500 μm, preferably the penetration depth is from 50 μm to 500 μm, more preferably the penetration depth is from 100 μm to 400 μm.

[0089] In a particular embodiment, the method does not implement compositions of the dual-cure type. In particular, the method does not implement compositions that are crosslinkable by polyaddition.

[0090] In certain embodiments, the method does not implement any post-curing step.

[0091] Preferably, the photo-crosslinkable silicone composition Y is prepared in a tank, and the silicone elastomer article is produced on a support, preferably a mobile support. The support can be any type of support. Advantageously, the support is a 3D printer platform, such as a mobile platform, or one or more already crosslinked layers of the photo-crosslinkable silicone composition Y.

[0092] According to a first embodiment of the method, the additive manufacturing process is performed layer by layer, each layer representing a cross-section of the object to be printed. This first embodiment is particularly suitable for laser stereolithography (SLA) printing and digital light processing (DLP). In this first embodiment, the irradiation step ii) may include the following sub-steps:

[0093] a. depositing a layer of a photocrosslinkable silicone composition Y on the stent;

[0094] b selectively irradiating the layer with a radiation source to form a first cross-section of the silicone elastomer to be prepared;

[0095] c. depositing an additional layer of a photocrosslinkable silicone composition Y on the first cross-section produced in step b); and

[0096] d. Selectively irradiating additional layers to form additional cross-sections of the silicone article to be prepared.

[0097] The support on which the layer of the photo-crosslinkable silicone composition Y is deposited in step a) can be any type of support. Preferably, it is a movable support. Advantageously, the support is a platform of a 3D printer, such as a mobile platform. The support can also include one or more crosslinked layers of the photo-crosslinkable silicone composition Y.

[0098] Preferably, in step d), the additional cross-section formed is adhered to the first cross-section of the silicone elastomer article formed in step b).

[0099] Advantageously, the thickness of the layer of photocrosslinkable silicone composition Y is from 0.1 μm to 500 μm, preferably from 5 μm to 400 μm, preferably from 10 μm to 300 μm, more preferably from 10 μm to 100 μm.

[0100] In a particular embodiment, the irradiation time of the layer of photocrosslinkable silicone composition Y is at least 0.001 seconds. Preferably, the irradiation time is from 0.001 seconds to 1 hour, preferably from 0.01 seconds to 5 minutes.

[0101] These various settings can be adjusted depending on the desired outcome.

[0102] Deposition of the layer of photocrosslinkable silicone composition Y can be achieved by moving the support or using a blade or doctor blade, which deposits a new layer of photocrosslinkable silicone composition Y.

[0103] Preferably, in the case where the radiation source is a laser (e.g. SLA process), the laser tracks the cross section of the silicone elastomer article to be produced to provide selective radiation, and in the case where the radiation source is a lamp (e.g. DLP process), it is a single image of the cross section projected onto the entire surface of the photocrosslinkable composition Y.

[0104] In the first embodiment, there are two alternatives: the additive manufacturing can be performed right side up or upside down. Both variants are described in document US5236637.

[0105] In a first alternative to this first embodiment, additive manufacturing is performed face-up: the photocrosslinkable silicone composition Y is contained in a tank, and the radiation source is focused onto the surface of the photocrosslinkable silicone composition Y. The irradiated layer is the layer between the support and the surface of the photocrosslinkable silicone composition Y. In this first alternative, the layer of photocrosslinkable silicone composition Y is deposited by lowering the support into the tank a distance corresponding to the layer thickness. A blade or doctor blade can then be passed over the surface of the photocrosslinkable silicone composition Y to level it.

[0106] In a second alternative to this first embodiment, additive manufacturing is reversed: the can comprises a transparent bottom and a non-adhesive surface, and the radiation source is focused on the transparent bottom of the can. Therefore, the irradiated layer is the layer located between the can bottom and the support. In this case, the layer of photo-crosslinkable silicone composition Y is deposited by lifting the support so that the photo-crosslinkable silicone composition Y is inserted between the can bottom and the support. The distance between the can bottom and the support corresponds to the thickness of the layer.

[0107] Advantageously, the additive manufacturing method is a method of additive manufacturing by digital light processing (DLP) photopolymerization in a tank, wherein additive manufacturing is performed face-up: the layer of the photocrosslinkable silicone composition Y is deposited by lowering a support in the tank by a distance equal to the layer thickness and a blade or doctor blade is swept over the surface of the photocrosslinkable silicone composition Y.

[0108] According to a second embodiment of the method, the additive manufacturing method is carried out continuously. This second embodiment is particularly suitable for the preparation by continuous liquid interface preparation (CLIP) described in document WO2014 / 126837. In this second embodiment, the irradiation step ii) may comprise the following sub-steps:

[0109] a. selectively irradiating at least a portion of the photocrosslinkable silicone composition Y using a radiation source to form a portion of a silicone elastomer article; and

[0110] b. Moving the portion of the silicone elastomer article formed in step a) away from the radiation source along the radiation axis.

[0111] Advantageously, in step a) the portion of the silicone elastomer part is formed on the support and in step b) the support is simultaneously moved.

[0112] Preferably, in this second embodiment, additive manufacturing is reversed: the can includes a transparent bottom, and the radiation source is focused on the transparent bottom of the can. Due to the oxygen-permeable membrane, photopolymerization occurs only at the interface between the photocrosslinkable silicone composition Y and the carrier, while the photocrosslinkable composition Y between the can bottom and the interface does not photopolymerize. Thus, by irradiating the photocrosslinkable composition Y while simultaneously removing the formed silicone elastomer part from the can, a continuous liquid interface can be maintained where the silicone elastomer article is formed.

[0113] Once the silicone elastomer article is obtained, it can be washed to remove the non-crosslinked photo-crosslinkable silicone composition Y.

[0114] Once the silicone elastomer article is obtained, additional steps may be performed to improve the surface quality of the article. For example, sandblasting is a known method for reducing or removing a visible layer. Silicone elastomer articles can also be sprayed or coated with LSR or RTV silicone compositions that can be crosslinked by heat or UV light to achieve a smooth appearance. Lasers can also be used to surface treat the resulting article.

[0115] For medical applications, the resulting silicone elastomer article can be sterilized. The article can be sterilized by heating (e.g., at temperatures above 100°C) in a dry environment or in a steam autoclave. Sterilization can also be performed using gamma rays, ethylene oxide, or electron beams.

[0116] The invention also relates to an article made of silicone elastomer obtained by the process described in this application.

[0117] The silicone elastomer article obtained can be any article with a simple or complex geometry. For example, it can be a silicone mold, a mask, a tube, an anatomical model (functional or non-functional), such as a heart, kidney, prostate, etc., a surgeon's or teaching model, an orthosis, a prosthesis such as a denture, an aligner, a mouthguard, or various types of implants, such as long-term implants, hearing aids, stents, laryngeal implants, etc.

[0118] The silicone elastomer article obtained can also be a jack for a robot, a seal, a mechanical part for the automotive or aviation industry, an electronic equipment part, a packaging component part, a vibration insulator, an impact insulator or a sound insulation material.

[0119] Photocrosslinkable silicone composition Y

[0120] The photocrosslinkable silicone composition Y obtained in the present method comprises:

[0121] a. at least one linear organopolysiloxane A having the general formula (I)

[0122] [Chemical Formula 4]

[0123]

[0124] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0125] E is a group comprising a cationically polymerizable and / or crosslinkable functional group, preferably an epoxy functional group or a vinyl oxide functional group, wherein the cationically polymerizable and / or crosslinkable functional group is attached to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen;

[0126] Each group X is independently R 1 or E;

[0127] a+b≥150; preferably 2000≥a+b≥150; and

[0128] The organopolysiloxane A has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups, and the molar content of the cationically polymerizable and / or crosslinkable functional groups in the organopolysiloxane A is less than or equal to 18 mmol / 100 g of the organopolysiloxane A, preferably less than or equal to 15 mmol / 100 g of the organopolysiloxane A;

[0129] b. Optionally, at least one linear organopolysiloxane B of the general formula (I), wherein

[0130] a+b≤100; preferably 1≤a+b≤100;

[0131] The organopolysiloxane B has at least two groups E containing cationically polymerizable and / or crosslinkable functional groups, preferably epoxy functional groups or vinyl oxide functional groups; and

[0132] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of organopolysiloxane B;

[0133] c. at least one cationic photoinitiator C;

[0134] d. Optionally, filler D,

[0135] e. Optionally, a photosensitizer E, and

[0136] f. Optionally, a light absorber F.

[0137] "Preparing a photo-crosslinkable silicone composition Y" refers to using a photo-crosslinkable silicone composition Y. The photo-crosslinkable silicone composition Y can be prepared according to methods known to those skilled in the art. Advantageously, the photo-crosslinkable silicone composition Y is prepared by mixing all components, for example, manually or in a speed mixer. Once the components are mixed, the photo-crosslinkable silicone composition Y can be degassed.

[0138] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane A is less than or equal to 18 mmol / 100 g of the organopolysiloxane A, and preferably less than or equal to 15 mmol / 100 g of the organopolysiloxane A. The molar content of the cationically polymerizable and / or crosslinkable functional groups can be, for example, from 0.5 mmol / 100 g of the organopolysiloxane A to 18 mmol / 100 g of the organopolysiloxane A, or from 1 mmol / 100 g of the organopolysiloxane A to 15 mmol / 100 g of the organopolysiloxane A.

[0139] In a specific embodiment, the organopolysiloxane of formula A is an organopolysiloxane of formula (I), wherein a+b≥200; preferably 1000≥a+b≥200.

[0140] The organopolysiloxane A is composed of siloxane units D: R 1 2SiO 2 / 2 and D E :ER 1 SiO 2 / 2 The siloxane unit "D" and the siloxane unit M selected from E :ER 1 2SiO 1 / 2 The symbol R 1 and E as above.

[0141] The linear organopolysiloxane A preferably comprises two groups E having cationically polymerizable and / or crosslinkable functional groups.

[0142] Advantageously, the organopolysiloxane A is an organopolysiloxane of formula (I) in which a = 0. The group E comprising a cationically polymerizable and / or crosslinkable functional group is then located at the end of the chain, and the organopolysiloxane A may have the general formula M E D x M E , wherein x≥150, preferably x≥200.

[0143] Organopolysiloxane A may be an oil having a dynamic viscosity of about 1 to 100,000 mPa.s at 25°C, typically about 10 to 70,000 mPa.s at 25°C, preferably about 10 to 30,000 mPa.s at 25°C, and even more preferably about 500 to 20,000 mPa.s at 25°C.

[0144] All viscosities discussed in this application correspond to what are called "Newtonian" dynamic viscosities at 25°C, i.e., dynamic viscosities measured with a Brookfield viscometer under a shear rate gradient low enough to make the measured viscosity independent of the shear rate gradient.

[0145] The photocrosslinkable silicone composition Y may contain at least 70 wt %, preferably 70 wt % to 99 wt %, more preferably 75 wt % to 90 wt % of the organopolysiloxane A, relative to the total weight of the photocrosslinkable silicone composition Y. The photocrosslinkable silicone composition Y may contain at least 75 wt % of the organopolysiloxane A.

[0146] The photocrosslinkable silicone composition Y may comprise a linear organopolysiloxane B of the general formula (I) wherein

[0147] a+b≤100; preferably 1≤a+b≤100; and

[0148] The molar content of the cationically polymerizable and / or crosslinkable functional groups in the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of the organopolysiloxane B.

[0149] The linear organopolysiloxane B has a shorter chain than the organopolysiloxane A and a higher molar content of cationically polymerizable and / or crosslinkable functional groups. This makes it possible to improve the mechanical properties of the silicone elastomer article obtained at the end of the process, while maintaining good elastomeric properties. In fact, the modulus of rupture and the hardness of the silicone elastomer obtained are increased, while maintaining a high elongation at break.

[0150] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of the organopolysiloxane B, preferably greater than or equal to 50 mmol / 100 g of the organopolysiloxane B, and more preferably greater than or equal to 80 mmol / 100 g of the organopolysiloxane B. The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B may be, for example, from 20 mmol / 100 g of the organopolysiloxane B to 500 mmol / 100 g of the organopolysiloxane B, or from 50 mmol / 100 g of the organopolysiloxane B to 250 mmol / 100 g of the organopolysiloxane B.

[0151] The organopolysiloxane B is composed of siloxane units D: R 1 2SiO 2 / 2 and D E :ER 1 SiO 2 / 2 The siloxane unit "D" and the siloxane unit M selected from E :ER 1 2SiO 1 / 2 The symbol R 1 and E as above.

[0152] The linear organopolysiloxane B preferably comprises two groups E having cationically polymerizable and / or crosslinkable functional groups.

[0153] In a specific embodiment, the organopolysiloxane B is an organopolysiloxane of formula (I) wherein a+b≤75; preferably 1≤a+b≤75.

[0154] Advantageously, the organopolysiloxane B is an organopolysiloxane of formula (I) in which a = 0. The group E comprising a cationically polymerizable and / or crosslinkable functional group is then located at the end of the chain, and the organopolysiloxane B may have the general formula M E D xM E , wherein x≤100, preferably x≤75.

[0155] The organopolysiloxane A may be an oil having a dynamic viscosity of about 1 to 100,000 mPa.s at 25°C, typically about 5 to 70,000 mPa.s at 25°C, and preferably about 10 to 1,000 mPa.s at 25°C.

[0156] The photocrosslinkable silicone composition Y may contain 1 to 20 wt % of the organopolysiloxane B, relative to the total weight of the photocrosslinkable silicone composition Y, preferably 5 to 15 wt % of the organopolysiloxane B.

[0157] The cationically polymerizable and / or crosslinkable functional group of group E is preferably selected from epoxy functional groups, vinyl oxide, oxetane and dioxolane functional groups. Advantageously, the cationically polymerizable and / or crosslinkable functional group of group E is an epoxy functional group or a vinyl oxide functional group, preferably an epoxy functional group.

[0158] When the functional group E which is polymerizable and / or crosslinkable by cationic route is an epoxy functional group, the group E of the organopolysiloxane A and / or organopolysiloxane B is preferably selected from the following groups:

[0159] [Chemical Formula 5]

[0160]

[0161] [Chemical Formula 6]

[0162]

[0163] [Chemical Formula 7]

[0164]

[0165] [Chemical Formula 8]

[0166] and

[0167] [Chemical Formula 9]

[0168]

[0169] The wavy line indicates the position where the group E is bonded to the silicon atom of the organopolysiloxane.

[0170] When the functional group of group E which is polymerizable and / or crosslinkable by a cationic route is a vinyl oxide functional group, the group E of the organopolysiloxane A and / or organopolysiloxane B is of formula (II):

[0171] -GO-CH=CH2 (II)

[0172] wherein G represents a divalent free radical comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen.

[0173] Preferably, the vinyloxy group is selected from the following groups:

[0174] -(CH3)2-O-CH=CH2;

[0175] -O-(CH2)4-O-CH=CH2; and

[0176] -(CH2)3-OR 11 -O-CH=CH2, where R 11 is selected from C1 to C 12 Branched or linear alkylene and C6 to C 12 Arylene, preferably phenylene, which is optionally substituted with one, two or three C1 to C6 alkyl groups.

[0177] Preferably, organopolysiloxane A and / or organopolysiloxane B is of formula (III):

[0178] [Chemical Formula 10]

[0179]

[0180] where R 1 As mentioned above, R 1 Preferred is methyl.

[0181] In the case of organopolysiloxane A, b is ≧150, preferably b≧200, and in the case of organopolysiloxane B, b is ≦100, preferably b≦75.

[0182] Advantageously, the cationic photoinitiator C is selected from Salt, preferably selected from diaryliodonium Salts, aryl diazonium salts, alkoxy pyridinium salts, triaryl iodides Salt, sulfur Salts and mixtures thereof. Preferably, the cationic photoinitiator C is a diaryl iodide Salt.

[0183] for The salt is the cationic part responsible for absorbing UV rays; on the other hand, the anionic part determines the strength of the acid formed and thus the initiation rate of polymerization. The weaker the nucleophilicity, the faster the photolysis reaction. Therefore, the various counterions used in cationic photoinitiators can be classified according to their reactivity (decreasing): (C6F5)4B > SbF6 – >>AsF6 – >PF6– >BF4 – . The salt may be boric acid Salt. Boric acid The salt may be chosen from those described in document US7041710 B2.

[0184] The salt is preferably iodine borate Advantageously, iodine borate Selected from:

[0185] A) wherein the cationic portion of the borate is selected from:

[0186] Formula (IV) Salt;

[0187] [(R 2 ) n -I-(R 3 ) m ] + (IV)

[0188] in:

[0189] -Free Radical R 2 Same or different, means C6 to C 20 aryl, or heteroaryl having 5 to 15 ring atoms,

[0190] -Free Radical R 3 Same or different, in accordance with R 2 Same definition, or means C1 to C 30 Branched or straight chain alkyl radicals, or C2 to C 30 branched or straight-chain alkenyl radicals;

[0191] The free radical R 2 and R 3 Optionally substituted with one or more of the following groups:

[0192] i) C1 to C 30 branched or straight chain alkyl groups,

[0193] ii)OR 12 Group,

[0194] iii) Keto group -(C=O)-R 12 ,

[0195] iv) ester or carboxyl group -(C=O)-OR 12 ,

[0196] v) Mercapto SR 12 base,

[0197] v) Mercapto SOR 12 base,

[0198] vii) C2 to C 30 A branched or straight-chain alkenyl group, optionally substituted by one or more C1 to C 30 Branched or straight chain alkyl, OR 12 group, -CN group and / or -(C=O)-OR 12 group substitution;

[0199] R 12 is selected from hydrogen atom, C1 to C 25 Branched or straight chain alkyl radicals, C6-C 30 Aryl radicals, or alkylaryl radicals, wherein the alkyl portion is C1 to C 25 Branched or straight chain alkyl, aryl part is C6 to C 30 Aryl,

[0200] viii) nitro group,

[0201] ix) a chlorine atom,

[0202] x) bromine atoms, and / or

[0203] xi) a cyano group,

[0204] -n is an integer from 1 to v+1, v is the valence of iodine,

[0205] - m is an integer from 0 to v-1, n+m=v+1; and

[0206] B) wherein the borate anion moiety has formula (V):

[0207] [BZ a R 4 b ] - (V)

[0208] in:

[0209] -a and b are integers, for example, 0≤a≤3, 1≤b≤4, a+b=4,

[0210] - Symbol Z is the same or different, indicating:

[0211] i) a halogen atom selected from chlorine and / or fluorine, 0≤a≤3, or

[0212] ii) OH functional group 0≤a≤2 and

[0213] -R 4 The free radicals are the same or different, indicating:

[0214] i) phenyl radicals, which are substituted by at least one electron-withdrawing group, such as -CF3, -OCF3, -NO2, CN, -SO2R 14 、-O(C=O)-R 14 、-OC n F 2n+1 、-C n F 2n+1 substituted, n being an integer from 1 to 20, or substituted by at least 2 halogen atoms, in particular fluorine atoms, or

[0215] ii) aromatic radicals containing at least two aromatic rings, such as biphenyl, naphthyl, which are optionally substituted by at least one halogen atom, in particular a fluorine atom, or an electron-withdrawing group, such as -CF3, -OCF3, -NO2, -CN, -SO2R 14 、-O(C=O)-R 14 、-OC n F 2n+1 and -C n F 2n+1 replace

[0216] R 14 For-OC n F 2n+1 , where -C n F 2n+1 , n is an integer from 1 to 20.

[0217] The borate anion is preferably selected from [B(C6F5)4] - 、[(C6F5)2BF2] - 、[B(C6H4CF3)4] - 、[B(C6F4OCF3)4] - 、[B(C6H3(CF3)2)4] - 、[B(C6H3F2)4] - 、[C6F5BF3] - and mixtures thereof.

[0218] According to a particular embodiment, iodine borate A compound selected from formula (VI):

[0219] [Chemical Formula 11]

[0220]

[0221] in:

[0222] -Symbol R 5 and R 6are the same or different and each represents a branched or straight-chain alkyl group having 10 to 30 carbon atoms, preferably 10 to 20 carbon atoms, even more preferably 10 to 15 carbon atoms, even more preferably 10 to 13 carbon atoms, even more preferably 12 carbon atoms,

[0223] - c and c' are identical or different integers from 1 to 5, preferably c and c' are equal to 1,

[0224] -Z, a, R 4 and b are as described above in formula (V).

[0225] According to a specific embodiment, iodine borate A compound selected from formula (VII):

[0226] [Chemical Formula 12]

[0227]

[0228] The symbol R 7 and R 8 Identical or different, each represents a branched or straight-chain alkyl radical having 10 to 30 carbon atoms, preferably 10 to 20 carbon atoms, even more preferably 10 to 15 carbon atoms.

[0229] According to a preferred embodiment, iodine borate A compound selected from formula (VIII):

[0230] [Formula 13]

[0231]

[0232] Salts may be used in combination with Guerbet alcohols to avoid off-flavors. Guerbet alcohols may be of formula (IX): R 9 -CH(CH2OH)-R 10 (IX)

[0233] in

[0234] Symbol R 9 and R 10 are identical or different and each represents an alkyl radical having 4 to 12 carbon atoms, the total number of carbon atoms of the Guerbet alcohol being 10 to 20.

[0235] In a specific embodiment, the cationic photoinitiator C is selected from the following Salt:

[0236] A) The cationic moiety is selected from the group consisting of Salt;

[0237] [(R 19)-I-(R 20 )] + (X),

[0238] The free radical R 19 is a free radical having formula (XI)

[0239] [Chemical Formula 14]

[0240]

[0241] in

[0242] -Free Radical R 19 It is connected to the iodine atom through a bond at one of positions 3 to 8, where R 21 -R 26 The substituent does not exist.

[0243] - the presence of a substituent R 21 to R 26 The same or different, represents a hydrogen atom, or C1 to C 12 Branched or straight chain alkyl, or keto-(C=O)-R 15 , or-OR 15 free radicals,

[0244] -R 15 is a group selected from the following: a hydrogen atom, a C1 to C 25 Branched or straight chain alkyl, C1 to C 25 Branched or linear halogenated alkyl, C6 to C 30 Aryl or alkylaryl, wherein the alkyl portion is C1 to C 25 Branched or straight chain alkyl, aryl part is C6 to C 30 aryl, said aryl and said alkylaryl are optionally substituted by one or more halogen atoms,

[0245] -R 20 Free radicals represent C6 to C 20 Aryl, or alkylaryl, wherein the alkyl portion is C1 to C 25 Branched or straight chain alkyl, aryl part is C6 to C 30 Aryl,

[0246] -Free Radical R 20 Optionally substituted with one or more of the following groups:

[0247] i) C1 to C 30 branched or straight chain alkyl groups,

[0248] i) C1 to C 30 branched or straight-chain halogenated alkyl groups,

[0249] iii)OR 16 Group,

[0250] iv) Keto group -(C=O)-R 16 ,

[0251] v) ester or carboxyl group -(C=O)-OR 16 ,

[0252] R 16 is a group selected from the following: a hydrogen atom, a C1-C 25 Branched or straight chain alkyl, C1-C 25 Branched or straight chain halogenated alkyl, C6-C 30 Aryl or alkylaryl, wherein the alkyl portion is C1-C 25 Branched or straight chain alkyl, aromatic part is C6-C 30 Aryl,

[0253] iv) nitro,

[0254] vii) halogen atoms, and

[0255] B) wherein the anion portion is selected from SbF6 - 、AsF6 - PF6 - , ClO4 or a borate of formula (V);

[0256] [BZ a R 4 b ] - (V)

[0257] Among them, Z, a, R 4 and b are as described in the above formula (V).

[0258] Preferably:

[0259] R 19 The free radical forms a bond with the iodine atom at position 3, so R 21 Free radicals do not exist.

[0260] -R 22 Corresponding to the methyl group,

[0261] -R 23 corresponds to a hydrogen atom, a methoxy group, a butoxy group or a benzyloxy group,

[0262] -R 24 For hydrogen atoms,

[0263] -R 25 corresponds to a hydrogen atom, a benzyloxy group, a methoxy group, a butoxy group or an ethoxy group,

[0264] -R26 corresponds to H, benzyloxy or methoxy, and

[0265] Free Radical R 20 represents phenyl, p-methylphenyl or naphthyl.

[0266] The borate ion is preferably selected from [B(C6F5)4] - 、[(C6F5)2BF2] - 、[B(C6H4CF3)4] - 、[B(C6F4OCF3)4] - 、[B(C6H3(CF3)2)4] - 、[B(C6H3F2)4] - 、[C6F5BF3] - and mixtures thereof.

[0267] Advantageously, the compound of formula (X) The salt is a compound having formula (XII)

[0268] [Chemical Formula 15]

[0269]

[0270] The anion portion is selected from SbF6 – PF6 – 、[B(C6F5)4] - .

[0271] In a specific embodiment, the cationic photoinitiator C is selected from the following Salt:

[0272] A) wherein the cationic moiety is selected from the group consisting of Salt;

[0273] [Chemical Formula 16]

[0274]

[0275] in

[0276] -Substituent R 31 、R 32 and R 33 The same or different, each represents H, C1 to C 12 Branched or straight chain alkyl, -OR 35 , -CN or -(C=O)-OR 35 alkyl;

[0277] -R 34 Indicates -OR 35 ;

[0278] R 35 is selected from H and C1-C 12 Free radicals with branched or straight-chain alkyl groups; and

[0279] B) wherein the anion portion is selected from SbF6 – 、AsF6 – PF6 – , ClO4 or borate of formula (V)

[0280] [BZ a R 4 b ] - (V)

[0281] Among them, Z, a, R 4 and b are as described in the above formula (V).

[0282] "Heteroaryl having 5 to 15 ring atoms" refers to an aromatic polyunsaturated ring system having 5 to 15 ring atoms, including one or more fused rings, wherein at least one ring is aromatic and at least one ring atom is a heteroatom selected from N, O and S.

[0283] According to the present invention, a "halogen atom" refers to an atom selected from the group consisting of fluorine, chlorine, bromine and iodine.

[0284] According to the present invention, "haloalkyl" refers to an alkyl group substituted by one or more halogen atoms.

[0285] According to a specific embodiment, the amount of cationic photoinitiator C is from 0.05% to 10% by weight, preferably from 0.1% to 5% by weight, more preferably from 0.15% to 3% by weight, relative to the total weight of the photocrosslinkable silicone composition Y.

[0286] According to a particular embodiment, the photocrosslinkable silicone composition Y is preferably free of any platinum-, palladium-, ruthenium- or rhodium-based catalysts. "Free" means that the photocrosslinkable silicone composition Y contains less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight of catalysts based on platinum-, palladium-, ruthenium- or rhodium-based catalysts relative to the total weight of the composition.

[0287] The photocrosslinkable silicone composition Y may contain a filler D. The filler D improves the mechanical properties of the silicone elastomer article obtained after the method is implemented, while maintaining good elastomeric properties. In particular, the filler D increases the modulus of rupture of the silicone elastomer article obtained while maintaining a high elongation at break.

[0288] The filler D which is optionally provided is preferably a mineral filler. The filler D can be a very fine product with an average particle size of less than 0.1 μm. The filler D can in particular be siliceous. For siliceous materials, they can act as reinforcing or semi-reinforcing fillers. Reinforcing siliceous fillers are selected from colloidal silica, pyrogenic and precipitated silica powders or mixtures thereof. These powders generally have an average particle size of less than 0.1 μm (micrometer) and a BET surface area of ​​more than 30 m 2 / g, preferably 30m 2 / g to 350m 2 / g. Semi-reinforcing siliceous fillers such as diatomaceous earth or ground quartz can also be used. These silicas can be added as is or after being treated with organosilicon compounds commonly used for this purpose. Among these compounds are methylpolysiloxanes (e.g., hexamethyldisiloxane, octamethylcyclotetrasiloxane), methylpolysilazanes (e.g., hexamethyldisilazane, hexamethylcyclotrisilazane), chlorosilanes (e.g., dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane), and alkoxysilanes (e.g., dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane). As for non-siliceous mineral materials, they can act as semi-reinforcing or filling mineral fillers. Examples of such non-siliceous fillers, which can be used alone or in mixtures, are calcium carbonate, optionally surface-treated with an organic acid or organic acid ester, calcined clay, rutile titanium oxide, oxides of iron, zinc, chromium, zirconium, or magnesium, various forms of aluminum oxide (hydrated or unhydrated), boron nitride, lithopone, barium metaborate, barium sulfate, and glass microspheres. These fillers are relatively coarse, with an average particle size generally greater than 0.1 μm and a specific surface area generally less than 30 m2 / g. These fillers can be surface-modified by processing with various organosilicon compounds commonly used for this purpose. From a weight perspective, the filler content is preferably from 0.1% to 50% by weight, preferably from 1% to 20% by weight, relative to all components of the photo-crosslinkable silicone composition Y.

[0289] Advantageously, the photocrosslinkable silicone composition Y comprises fillers D in an amount of from 0.1% to 15% by weight, preferably from 1% to 12% by weight.

[0290] The photocrosslinkable silicone composition Y may include a photosensitizer E. The photosensitizer E absorbs energy from radiation and transfers it as energy or electrons to the cationic photoinitiator C. Advantageously, the photosensitizer absorbs radiation energy of a higher wavelength than the cationic photoinitiator C, which makes it possible to use a radiation source having a wavelength higher than the wavelength at which the photoinitiator cation C is activated. The use of the photosensitizer E is particularly suitable for using an LED lamp as the radiation source, for example an LED lamp having a wavelength of 355 nm, 365 nm, 385 nm or 405 nm.

[0291] Advantageously, the photosensitizer E is selected from naphthalene, anthracene, pyrene, phenothiazine, ketones, thioxanthones, benzophenones, acetophenones, carbazoles, anthraquinones, fluorenones, acylphosphine oxides, camphorquinones, and mixtures thereof.

[0292] According to a specific embodiment, the photosensitizer E is selected from anthracene, naphthalene, perylene, pyrene, phenothiazine, 9,10-benzanthraquinone, dianthrone, anthrone, 9-butoxyanthracene, 1-ethyl-9,10-dimethoxyanthracene, acridine orange, benzoflavin, 1-ethyl-9-ethoxyanthracene, 1-ethyl-9,10-dimethoxyanthracene, 2-isopropylthioxanthone, 2-chlorothioxanthone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4-dimethylaminobenzophenone and mixtures thereof. Preferably, the photosensitizer E is 2-isopropylthioxanthone.

[0293] The photocrosslinkable silicone composition Y may contain 0.001 to 1 wt. %, preferably 0.002 to 0.5 wt. %, even more preferably 0.005 to 0.1 wt. % of a photosensitizer E, relative to the total weight of the photocrosslinkable silicone composition Y. The photocrosslinkable silicone composition Y may contain 0.001 to 0.1 wt. % of a photosensitizer E.

[0294] The photocrosslinkable silicone composition Y may contain a light absorber F. The light absorber F can reduce the radiation penetration of the crosslinkable silicone composition Y layer, thereby improving the resolution of the resulting silicone elastomeric article. This makes it possible to control the radiation penetration depth (Dp) in the elastomeric silicone Y layer.

[0295] The photocrosslinkable silicone composition Y comprises 0.01 to 5 wt % of a light absorber F relative to the total weight of the photocrosslinkable silicone composition Y. Preferably, the light absorber F is selected from TiO2, ZnO, hydroxyphenyl-s-triazine, hydroxyphenylbenzotriazole, cyanoacrylate, and mixtures thereof.

[0296] The photocrosslinkable silicone composition Y may also comprise organic or inorganic pigments G.

[0297] The photocrosslinkable silicone composition Y may also comprise at least one organic compound H which comprises epoxy and / or vinyl functional groups.

[0298] The dynamic viscosity of the photocrosslinkable silicone composition Y at 25° C. is about 1 mPa.s to 100,000 mPa.s, typically 10 mPa.s to 50,000 mPa at 25° C., preferably 100 mPa.s to 15,000 mPa at 25° C.

[0299] Advantageously, the photocrosslinkable silicone composition Y obtained in this method comprises:

[0300] At least one linear organopolysiloxane A having the general formula (I)

[0301] [Chemical Formula 17]

[0302]

[0303] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0304] E is a group comprising an epoxy functional group, wherein the epoxy functional group is bonded to the silicon atom through a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen;

[0305] a. Each group X is independently R 1 or E;

[0306] a+b≥150; preferably 2000≥a+b≥150;

[0307] The organopolysiloxane A has at least two groups E containing epoxy functional groups, and

[0308] The molar content of epoxy functional groups in the organopolysiloxane A is less than or equal to 18 mmol / 100 g of organopolysiloxane A, preferably less than or equal to 15 mmol / 100 g of organopolysiloxane A.

[0309] b. Optionally, at least one linear organopolysiloxane B of the general formula (I), wherein

[0310] a+b≤100; preferably 1≤a+b≤100;

[0311] The organopolysiloxane B has at least two groups E containing epoxy functional groups, and

[0312] The molar content of epoxy functional groups in the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of organopolysiloxane B;

[0313] c. at least one cationic photoinitiator C;

[0314] d. Optionally, filler D,

[0315] e. Optionally, a photosensitizer E, and

[0316] f. Optionally, a light absorber F,

[0317] Photocrosslinkable organosilicone composition Y'

[0318] The present invention also relates to a photocrosslinkable organosilicone composition Y' comprising:

[0319] a. at least 75% by weight of a linear organopolysiloxane A having the general formula (I)

[0320] [Chemical Formula 18]

[0321]

[0322] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0323] E is a group comprising a cationically polymerizable and / or crosslinkable functional group, preferably an epoxy functional group or a vinyl oxide functional group, wherein the cationically polymerizable and / or crosslinkable functional group is attached to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen;

[0324] Each group is independently R 1 or E;

[0325] a+b≥200; preferably 2000≥a+b≥200;

[0326] The organopolysiloxane A' has at least two groups E comprising cationically polymerizable and / or crosslinkable functional groups; and

[0327] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane A' is less than or equal to 18 mmol / 100 g of the organopolysiloxane A', preferably less than or equal to 15 mmol / 100 g of the organopolysiloxane A';

[0328] b. 1 to 20% by weight of a linear organopolysiloxane B' of the general formula (I), wherein

[0329] a+b≤150; preferably 1≤a+b≤100;

[0330] The organopolysiloxane B' has at least two groups E comprising cationically polymerizable and / or crosslinkable functional groups, preferably epoxy functional groups or vinyl oxide functional groups, and

[0331] The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B' is greater than or equal to 20 mmol / 100 g of the organopolysiloxane B';

[0332] c. At least one cationic photoinitiator C.

[0333] The photo-crosslinkable silicone composition Y' is capable of crosslinking to the silicone elastomer by photopolymerization.

[0334] The molar content of cationically polymerizable and / or crosslinkable functional groups in organopolysiloxane A' is less than or equal to 18 mmol / 100 g of organopolysiloxane A', and preferably less than or equal to 15 mmol / 100 g of organopolysiloxane A'. The molar content of cationically polymerizable and / or crosslinkable functional groups can be, for example, from 0.5 mmol / 100 g of organopolysiloxane A' to 18 mmol / 100 g of organopolysiloxane A', or from 1 mmol / 100 g of organopolysiloxane A' to 15 mmol / 100 g of organopolysiloxane A'.

[0335] In a particular embodiment, the organopolysiloxane of formula A′ is an organopolysiloxane of formula (I), wherein 1000≧a+b≧200.

[0336] The organopolysiloxane A' is composed of siloxane units D:R 1 2SiO 2 / 2 and D E :ER 1 SiO 2 / 2 The siloxane unit "D" and the siloxane unit M selected from E :ER 1 2SiO 1 / 2 The symbol R 1 and E as above.

[0337] The linear organopolysiloxane A' preferably comprises two groups E having cationically polymerizable and / or crosslinkable functional groups.

[0338] Advantageously, the organopolysiloxane A' is an organopolysiloxane of formula (I) wherein a = 0. The group E comprising a cationically polymerizable and / or crosslinkable functional group is then located at the end of the chain, and the organopolysiloxane A may have the general formula M E D x M E , where x ≥ 200.

[0339] The organopolysiloxane A' may be an oil having a dynamic viscosity of about 1 to 100,000 mPa.s at 25°C, typically about 10 to 70,000 mPa.s at 25°C, preferably about 10 to 30,000 mPa.s at 25°C, and even more preferably about 500 to 20,000 mPa.s at 25°C.

[0340] The photocrosslinkable silicone composition Y' comprises at least 75 wt. % of organopolysiloxane A', preferably 75 wt. % to 99 wt. %, more preferably 75 wt. % to 90 wt. %, relative to the total weight of the photocrosslinkable silicone composition Y'.

[0341] The linear organopolysiloxane B' has a shorter chain and a higher molar content of cationically polymerizable and / or crosslinkable functional groups than the organopolysiloxane A'. This makes it possible to improve the mechanical properties of the silicone elastomer article obtained at the end of the photopolymerization while maintaining good elastomeric properties. In fact, the modulus of rupture and hardness of the silicone elastomer obtained are increased while maintaining a high elongation at break.

[0342] The molar content of cationically polymerizable and / or crosslinkable functional groups in organopolysiloxane B' is greater than or equal to 20 mmol / 100 g of organopolysiloxane B', preferably greater than or equal to 50 mmol / 100 g of organopolysiloxane B', and more preferably greater than or equal to 80 mmol / 100 g of organopolysiloxane B'. The molar content of cationically polymerizable and / or crosslinkable functional groups in organopolysiloxane B' can be, for example, from 20 to 500 mmol / 100 g of organopolysiloxane B', or from 50 to 250 mmol / 100 g of organopolysiloxane B'.

[0343] The organopolysiloxane B' is composed of siloxane units D: R 1 2SiO 2 / 2 and D E :ER 1 SiO 2 / 2 The siloxane unit "D" and the siloxane unit M selected from E :ER 1 2SiO 1 / 2 The symbol R 1 and E as above.

[0344] The linear organopolysiloxane B′ preferably comprises two groups E having cationically polymerizable and / or crosslinkable functional groups.

[0345] In a specific embodiment, the organopolysiloxane B′ is an organopolysiloxane in formula (I), wherein a+b≤75; preferably 1≤a+b≤75.

[0346] Advantageously, the organopolysiloxane B' is an organopolysiloxane of formula (I) wherein a = 0. The group E comprising a cationically polymerizable and / or crosslinkable functional group is then located at the end of the chain, and the organopolysiloxane B' may have the general formula M E D x M E , wherein x≤100, preferably x≤75.

[0347] The organopolysiloxane B' may be an oil having a dynamic viscosity of about 1 to 100,000 mPa.s at 25°C, typically about 5 to 70,000 mPa.s at 25°C, and preferably about 10 to 10,000 mPa.s at 25°C.

[0348] The photocrosslinkable silicone composition Y comprises 1% to 20% by weight of the organopolysiloxane B′, preferably 5% to 15% by weight of the organopolysiloxane B′, relative to the total weight of the photocrosslinkable silicone composition Y.

[0349] The cationically polymerizable and / or crosslinkable functional group of group E is preferably selected from epoxy functional groups, vinyl oxide functional groups, oxetane and dioxetane functional groups. Advantageously, the cationically polymerizable and / or crosslinkable functional group of group E is an epoxy functional group or a vinyl oxide functional group, preferably an epoxy functional group.

[0350] When the cationic polymerizable and / or crosslinkable functional group of the group E is an epoxy functional group, the group E of the organopolysiloxane A' and / or organopolysiloxane B' is preferably selected from the following groups:

[0351] [Chemical Formula 19]

[0352]

[0353] [Chemical Formula 20]

[0354]

[0355] [Chemical Formula 21]

[0356]

[0357] [Chemical Formula 22]

[0358] and

[0359] [Chemical Formula 23]

[0360]

[0361] The wavy line indicates the position where the group E is bonded to the silicon atom of the organopolysiloxane.

[0362] When the functional group polymerizable and / or crosslinkable via the cationic route of the group E is a vinyl oxide functional group, the group E of the organopolysiloxane A' and / or organopolysiloxane B' is of formula (II):

[0363] -GO-CH=CH2 (II)

[0364] Wherein G represents a divalent free radical, consisting of 2 to 20 carbon atoms and optionally one or more heteroatoms, the heteroatom being preferably oxygen.

[0365] Preferably, the vinyloxy group is selected from the following groups:

[0366] -(CH3)2-O-CH=CH2;

[0367] -O-(CH2)4-O-CH=CH2; and

[0368] -(CH2)3-OR 11 -O-CH=CH2, where R 11 is selected from C1 to C 12 Branched or linear alkylene and C6 to C 12 Arylene, preferably phenylene, which is optionally substituted with one, two or three C1 to C6 alkyl groups.

[0369] Preferably, the organopolysiloxane A' and / or organopolysiloxane B' is of formula (III):

[0370] [Chemical Formula 24]

[0371]

[0372] where R 1 As mentioned above, R 1 Preferred is methyl.

[0373] In the case of organopolysiloxane A', b is ≥ 150, preferably b ≥ 200, and in the case of organopolysiloxane B', b is ≤ 100, preferably b ≤ 75

[0374] According to a specific embodiment, the amount of cationic photoinitiator C is 0.05% to 10% by weight, preferably 0.1% to 5% by weight, and more preferably 0.15% to 3% by weight, relative to the total weight of the photocrosslinkable silicone composition Y. Cationic photoinitiator C is used in the photocrosslinkable silicone composition Y as described above. According to a specific embodiment, the photocrosslinkable silicone composition Y' is preferably free of any platinum-, palladium-, ruthenium-, or rhodium-based catalyst. "Free" means that the photocrosslinkable silicone composition Y' contains less than 0.1% by weight, preferably less than 0.01% by weight, and more preferably less than 0.001% by weight of a platinum-, palladium-, ruthenium-, or rhodium-based catalyst, relative to the total weight of the composition.

[0375] The photo-crosslinkable silicone composition Y' may contain a filler D. Filler D improves the mechanical properties of the silicone elastomer obtained after crosslinking while maintaining good elastomeric properties. In fact, the resulting silicone elastomer has an increased modulus of rupture while maintaining a high elongation at break. Filler D can be used in the photo-crosslinkable silicone composition Y as described above. The photo-crosslinkable silicone composition Y' may contain 1 to 50 wt. %, preferably 1 to 20 wt. %, relative to all components of the photo-crosslinkable silicone composition Y'.

[0376] Advantageously, the photocrosslinkable silicone composition Y′ comprises fillers D in an amount of from 0.1% to 15% by weight, preferably from 1% to 12% by weight.

[0377] The photocrosslinkable silicone composition Y' may include a photosensitizer E. The photosensitizer E absorbs energy from radiation and transfers it as energy or electrons to the cationic photoinitiator C. Advantageously, the photosensitizer absorbs radiation energy at a higher wavelength than the cationic photoinitiator C, which allows for the use of a radiation source having a wavelength higher than that at which the cationic photoinitiator C is activated. The photosensitizer E is used in the photocrosslinkable silicone composition Y as described above. The photocrosslinkable silicone composition Y' contains 0.001 to 0.5 weight percent, preferably 0.005 to 0.5 weight percent, of the photosensitizer E, relative to the total weight of the photocrosslinkable silicone composition Y'. The photocrosslinkable silicone composition Y' may contain 0.001 to 0.1 weight percent of the photosensitizer E.

[0378] The photocrosslinkable silicone composition Y' may include a light absorber F. The light absorber F can reduce radiation penetration through the crosslinkable silicone composition Y' layer, thereby increasing the radiation. This allows for control of the radiation penetration depth (Dp) in the photocrosslinkable silicone elastomer Y' layer. The photocrosslinkable silicone composition Y' may include 0.01 wt% to 5 wt% of the light absorber F, relative to the total weight of the photocrosslinkable silicone composition Y'. The light absorber F may be as described for the photocrosslinkable composition Y.

[0379] The photocrosslinkable silicone composition Y′ may also comprise organic or inorganic pigments G.

[0380] The photocrosslinkable silicone composition Y′ may further comprise at least one organic compound H comprising epoxy and / or vinyl oxide functional groups.

[0381] The dynamic viscosity of the photocrosslinkable silicone composition Y' at 25°C is about 1 mPa.s to 100,000 mPa.s, typically about 10 mPa.s to 50,000 mPa at 25°C, preferably about 100 mPa.s to 15,000 mPa at 25°C.

[0382] Advantageously, the photocrosslinkable silicone composition Y' comprises:

[0383] a. at least 75% by weight of a linear organopolysiloxane having the general formula (I) A'

[0384] [Chemical Formula 25]

[0385]

[0386] Each group R 1 is independently a monovalent group containing 1 to 30 carbon atoms, preferably selected from alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms, more preferably selected from methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl;

[0387] E is a group comprising an epoxy functional group, wherein the epoxy functional group is bonded to the silicon atom through a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms, preferably oxygen;

[0388] Each group X is R 1 or E;

[0389] a+b≥200; preferably 2000≥a+b≥200;

[0390] The organopolysiloxane A' has at least two groups E having epoxy functionality, and

[0391] The molar content of epoxy functional groups in the organopolysiloxane A' is less than or equal to 18 mmol / 100 g of organopolysiloxane A', preferably less than or equal to 15 mmol / 100 g of organopolysiloxane A';

[0392] b. 1 to 20% by weight of a linear organopolysiloxane B' of the general formula (I), wherein

[0393] a+b≤150; preferably 1≤a+b≤100;

[0394] The organopolysiloxane B' has at least two groups E containing epoxy functional groups, and

[0395] The molar content of epoxy functional groups in the organopolysiloxane B' is greater than or equal to 20 mmol / 100 g of organopolysiloxane B';

[0396] c. At least one cationic photoinitiator C.

[0397] The present invention also relates to the use of a photocrosslinkable silicone composition Y' for the additive manufacturing of silicone elastomer articles. Advantageously, the additive manufacturing is carried out by photopolymerization in a tank, preferably by laser stereolithography (SLA), digital light processing (DLP) 3D printing or continuous liquid interface preparation (or CLIP).

[0398] The invention also relates to silicone elastomers obtained by crosslinking a photocrosslinkable silicone composition Y'.

[0399] Example

[0400] Using basic materials

[0401] Oil A1: having formula M Epoxy D x M Epoxy An organopolysiloxane having epoxy functional groups, x=590, a molar mass of 44,000 g / mol, a viscosity of 9,150 mPa.s and a molar content of epoxy functional groups of 4.55 mmol / 100 g oil A1;

[0402] Oil A2: having the formula M Epoxy D x M Epoxy An organopolysiloxane having epoxy functional groups, wherein x=227, a molar mass of 17200 g / mol, a viscosity of 1000 mPa.s, and an epoxy functional group molar content of 11.53 mmol / 100 g of oil A2;

[0403] Oil A3: has formula MD 530 D Epoxy 9M epoxy-functional organopolysiloxane, with a molar mass of 41,600 g / mol, a viscosity of 5,000 mPa.s, and a molar content of epoxy functional groups of 21.64 mmol / 100 g oil A3;

[0404] Cationic photoinitiator C: Cationic photoinitiator having formula (VI) in octyldodecanol

[0405] [Chemical Formula 26]

[0406]

[0407] Photosensitizer E: ITX isopropylthioxanthone (CAS No. 5495-84-1);

[0408] Oil B: having formula M Epoxy D 21 M Epoxy The organopolysiloxane with epoxy functional groups has a molar mass of 1950 g / mol, a viscosity of 50 mPa.s, and a molar content of epoxy functional groups of 102.6 / 100 g oil B.

[0409] Filler D1: fumed silica treated with octamethyltetrasiloxane;

[0410] Filler D2: Untreated silica (A200):

[0411] Light absorber F: TiO2 (KronoClean 7000).

[0412] Different compositions were prepared using these products. All amounts are expressed as weight percentages relative to the total weight of the composition.

[0413] Compositions 1-9 and Comparative Composition 1

[0414] Compositions 1-9 and Comparative Composition 1 were prepared by mixing all components manually or using a speed mixer. The components were then degassed using a vacuum hood for 5 to 10 minutes. A portion of each component was cast into a 2 mm thick mold and passed through a laboratory apparatus consisting of a conveyor equipped with a UV lamp to produce plaques for mechanical testing after crosslinking.

[0415] Operating conditions of the laboratory unit:

[0416] i. Speed: 10m / min

[0417] II lamp: H-type bulb, medium pressure mercury vapor bulb, produces normal mercury spectral output,

[0418] iii.Power: 15A

[0419] iv. No product inerting

[0420] v.1 run

[0421] The mechanical properties of these compositions were measured according to ASTM D412 standard - Method A on an INSTRON 5544 dynamometer at a speed of 500 mm / min.

[0422] The different compositions and mechanical test results are shown in Table 1.

[0423] [Table 1]

[0424]

[0425] *N / A: Not measured

[0426] These results demonstrate that all compositions 1 to 9 according to the present invention are elastomers exhibiting high elongations at break of approximately 100% or greater. These results also demonstrate that, in order to achieve good elastomeric properties, it is necessary to use a composition comprising a long-chain organopolysiloxane having a low content of cationically polymerizable and / or crosslinkable functional groups. In fact, when an organopolysiloxane having a high content of cationically polymerizable and / or crosslinkable functional groups is used, the elongation at break is very low, and thus good elastomeric properties are not achieved (Comparative Composition 1).

[0427] The addition of shorter oils B with a higher molar content of cationically polymerizable and / or crosslinkable functional groups (compositions 4 to 7) or the addition of fillers (compositions 8 to 9) makes it possible to improve the mechanical properties of the elastomers obtained while maintaining good elastomeric properties. This is because the modulus of rupture and the hardness of these components increase, while the elongation at break remains high.

[0428] Compositions 10 to 12

[0429] Compositions 10 to 12 were prepared in the same manner by mixing all the components and then degassing the resulting compositions. In the case of composition 10, irradiation was performed using a mercury UV lamp, and in the cases of compositions 11 and 12, irradiation was performed using an LED lamp with a wavelength of 365 nm.

[0430] The reactivity under UV mercury lamp irradiation and at 365 nm was measured by photo DSC (Metler-Toledo LA61310) as follows: the sample was irradiated using a Hamamatsu LC8-02 lamp set to 1% after stabilization for 1 minute. For irradiation in the 365 nm UV LED range, a Hamamatsu A9616-07 filter was placed (UV dose at 365 nm measured under these conditions: 0.5 mW / cm 2 ).

[0431] The different compositions and mechanical test results are shown in Table 2.

[0432] [Table 2]

[0433]

[0434]

[0435] These results show that different types of radiation can be used to crosslink the compositions according to the invention. In the case of radiation by LEDs with a wavelength of 365 nm, a photosensitizer must be used to carry out the crosslinking reaction (compositions 11 and 12).

[0436] Compositions 13 to 16

[0437] Compositions 13 to 16 were prepared in the same manner by mixing all components and then degassing the obtained compositions.

[0438] By setting the exposure time to 1 or 3 seconds and varying the power of the UV source within this fixed exposure time, the effective depth of light penetration (the depth to which the composition is crosslinked) was measured. After film formation, measurements were made using a micrometer, which determined the depth of the layer formed according to the UV dose for each composition.

[0439] Table 3 lists the different compositions and the results obtained.

[0440] [Table 3]

[0441]

[0442]

[0443] These results show that it is possible to adjust the crosslinking depth. Adding light absorber F to the composition allows reducing light penetration, thus achieving better printing resolution. This makes it possible to obtain formulations that are compatible with 3D printing and have good printing resolution.

[0444] In addition, the mechanical properties of composition 13 were measured according to the above method. The results are shown in Table 4.

[0445] [Table 4]

[0446] characteristic Composition 13 Elongation at break (%) 145 100% modulus (MPa) 1.73 Modulus of rupture (MPa) 2.47 Hardness (Shore A) 37 Viscosity mPa.s 6000

[0447] These results demonstrate that it is possible to obtain formulations compatible with 3D printing for printing elastomeric parts with good mechanical properties and good definition.

Claims

1. An in-tank photopolymerization additive manufacturing method for preparing a silicone elastomer article, the method comprising the following steps: i. Implementation of a photo-crosslinkable silicone composition Y and a radiation source, the photo-crosslinkable silicone composition Y comprising: a. At least one linear organopolysiloxane of formula (I) A [Chemical Formula 27] (I) Each group R 1 are independently monovalent groups comprising 1 to 30 carbon atoms; E is a group comprising a cationically polymerizable and / or crosslinkable functional group, wherein the cationically polymerizable and / or crosslinkable functional group is linked to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms; Each group X is independently R 1 or E; 1000 ≥ a+b ≥ 200; The organopolysiloxane A has at least two groups E having cationically polymerizable and / or crosslinkable functional groups; and The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane A is less than or equal to 18 mmol / 100 g of organopolysiloxane A; b. at least one linear organopolysiloxane B having the general formula (I), wherein a+b≤100; The organopolysiloxane B has at least two groups E having cationically polymerizable and / or crosslinkable functional groups; and The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B is greater than or equal to 20 mmol / 100 g of organopolysiloxane B; c. at least one cationic photoinitiator C; d. Optionally, filler D, e. Optionally, a photosensitizer E, and f. Optionally, a light absorber F, ii. selectively irradiating at least a portion of the photo-crosslinkable silicone composition Y using the radiation source to form a portion of a silicone elastomer article; and iii. Repeating step ii) a sufficient number of times to prepare a silicone elastomer article, wherein the photocrosslinkable silicone composition Y comprises at least 75% by weight of an organopolysiloxane A, The photocrosslinkable silicone composition Y comprises an organopolysiloxane B in an amount of 1% to 20% by weight.

2. The additive manufacturing method for preparing silicone elastomer products by photopolymerization in a tank according to claim 1, characterized in that The organopolysiloxane A is an organopolysiloxane of formula (I), wherein a=0.

3. The additive manufacturing method for preparing silicone elastomer products by photopolymerization in a tank according to claim 1 or 2, characterized in that The cationically polymerizable and / or crosslinkable functional group of group E is an epoxy functional group.

4. The additive manufacturing method for preparing silicone elastomer products by photopolymerization in a tank according to claim 1 or 2, characterized in that The amount of the cationic photoinitiator C is 0.05% to 10% by weight of the photocrosslinkable silicone composition Y.

5. The additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank according to claim 1 or 2, characterized in that The cationic photoinitiator C is selected from Salt.

6. The additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank according to claim 1 or 2, characterized in that The photocrosslinkable silicone composition Y comprises a filler D in an amount of 0.1% to 15% by weight.

7. The additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank according to claim 1 or 2, characterized in that The photocrosslinkable silicone composition Y contains 0.001 to 0.1% by weight of a photosensitizer E.

8. The additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank according to claim 1 or 2, characterized in that The photocrosslinkable silicone composition Y contains a light absorber F in an amount of 0.01 to 5% by weight.

9. The additive manufacturing method for preparing silicone elastomer articles by photopolymerization in a tank according to claim 1 or 2, characterized in that The radiation source is an LED lamp.

10. A silicone elastomer article obtained by the method according to any one of claims 1 to 9.

11. A photocrosslinkable silicone composition Y' comprising: a. At least 75% by weight of a linear organopolysiloxane of formula (I) A ' [Chemical Formula 33] (I) Each group R 1 are independently monovalent groups comprising 1 to 30 carbon atoms; E is a group comprising a cationically polymerizable and / or crosslinkable functional group, wherein the cationically polymerizable and / or crosslinkable functional group is linked to the silicon atom via a divalent group comprising 2 to 20 carbon atoms and optionally 1 or more heteroatoms; Each group X is independently R 1 or E; a+b≥ 200; The organopolysiloxane A' has at least two groups E having cationically polymerizable and / or crosslinkable functional groups; and The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane A' is less than or equal to 18 mmol / 100 g of organopolysiloxane A'; b. 1% to 20% by weight of a linear organopolysiloxane B' having the general formula (I), wherein a+b≤150; The organopolysiloxane B' has at least two groups E having cationically polymerizable and / or crosslinkable functional groups, and The molar content of the cationically polymerizable and / or crosslinkable functional groups of the organopolysiloxane B' is greater than or equal to 20 mmol / 100 g of the organopolysiloxane B'; c. At least one cationic photoinitiator C.

12. The photocrosslinkable silicone composition Y' according to claim 11, characterized in that The organopolysiloxane A' is an organopolysiloxane of formula (I) wherein a=0.

13. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that The cationically polymerizable and / or crosslinkable functional group of group E is an epoxy functional group.

14. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that The amount of the cationic photoinitiator C is 0.05 wt % to 10 wt %.

15. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that The cationic photoinitiator C is selected from Salt.

16. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that 0.1 to 15 wt% of filler D is also included.

17. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that It also contains 0.001 to 0.1 wt% of a photosensitizer E.

18. The photocrosslinkable silicone composition Y' according to claim 11 or 12, characterized in that The light absorber F is also contained in an amount of 0.01 to 5 wt%.

19. Use of the photocrosslinkable silicone composition Y' according to any one of claims 11 to 18 for producing articles made of silicone elastomer.

20. A silicone elastomer obtained by crosslinking the photocrosslinkable silicone composition Y' according to any one of claims 11 to 18.

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