Type I photoinitiators for the curing of silicone compositions

Abstract

The present invention relates to a type I photoinitiator for the free radical curing of radiation curable compositions. In particular, the present invention relates to a silicone composition comprising a type I photoinitiator and an organopolysiloxane having at least one (meth)acrylate group.

Description

[Technical field]

[0001] [1] The subject of the present invention is a type I photoinitiator for the free-radical curing of radiation-curable compositions. In particular, the present invention relates to a silicone composition comprising a type I photoinitiator and an organopolysiloxane containing at least one (meth)acrylate group. [Background technology]

[0002] [2] The use of plastic films as substrate materials for the surface application of silicone coatings to produce release coatings (non-stick coatings) requires appropriate technology. In fact, most of these plastic films are heat-sensitive. Thus, dimensional deformations of the film occur during coating and drying of the silicone layer in a hot oven under the combined influence of tension and the temperature to which the film is subjected. The technology of curing functional silicone oils by radiation, especially ultraviolet (UV) radiation, excludes the use of high temperatures, thereby making it possible to cure the release coating layer without affecting the substrate. Furthermore, this technology has the advantage of achieving high productivity without high energy consumption and without the use of solvents. Plastic substrates are the materials of choice for many applications, and their use is constantly growing.

[0003] [3] The preparation of silicone release coatings is generally carried out as follows: the silicone composition is applied to a substrate in an industrial coating apparatus that includes rollers operating at very high speeds (e.g., 600 m / min). Once applied to the substrate, the silicone composition is cured to form a solid silicone (e.g., elastomeric) release coating. The resulting coated substrate is also called a silicone liner. This silicone liner can in particular be laminated with an adhesive, since the silicone release coating facilitates the removal of adhesive materials reversibly bonded to these substrates. These silicone liners can therefore be used in the fields of labels that do not require glue, strips including envelopes, graphic arts, medical and health applications.

[0004] [4] Silicone compositions used to form release coatings are generally cured (crosslinked) by exposure to radiation, particularly ultraviolet or visible radiation emitted by doped or undoped mercury lamps with emission spectra extending from 200 nm to 450 nm. Light sources providing spot UV or visible light, such as light emitting diodes, better known by the acronym "LED," can also be used.

[0005] [5] Radiation curing of functional silicone oils can be carried out according to two approaches: cationic polymerization of epoxy groups or free radical polymerization of acrylic functional groups. Free radical polymerization is not inhibited by either bases or moisture. Therefore, coating substrates and additives can be more diverse, and interest in such free radical systems is increasing.

[0006] [6] Free radical polymerization of molecules with acrylic functionality by irradiation, especially UV irradiation, is well documented. The general consensus is that radiation-induced curing is promoted by radical photoinitiator molecules. A large body of literature describes radical photoinitiators and their uses. In the field of free radical polymerization of acrylic silicone compositions, the photoinitiator molecules commonly used are called type I photoinitiators. Upon irradiation, these molecules split to generate free radicals. These free radicals initiate the polymerization initiation reactions that lead to the curing of the composition. Many efforts have been made to make type I photoinitiators retain the properties that allow their use in silicone-acrylic formulations to obtain release coatings. Throughout this application, the phrase "type I photoinitiator" is understood to mean a compound that is capable of generating polymerization-initiating free radicals upon irradiation by homolytic cleavage within the molecule.

[0007] [7] There are also Type II photoinitiator systems that contain a radical photoinitiator and a co-initiator. In Type II photoinitiator systems, the photoinitiator used is capable of generating polymerization-initiating free radicals by reaction with another compound called a co-initiator, which reaction results in the transfer of hydrogen from the co-initiator to the photoinitiator. Photoinitiators used in Type II photoinitiator systems are called "Type II photoinitiators".

[0008] [8] Type I photoinitiators are commercially available, but they can have drawbacks. In particular, their solubility in silicone compositions is not always optimal. Furthermore, photoinitiators and their decomposition products, such as benzaldehyde, can pose health risks and have an unpleasant odor.

[0009] [9] Therefore, there is a need to develop type I photoinitiators that can overcome these drawbacks. Summary of the Invention [Problem to be solved by the invention]

[0010]

[10] In this regard, the present invention aims to meet at least one of the following objectives:

[11] One essential object of the present invention is to provide a radiation-curable silicone composition containing a Type I photoinitiator that can be used to form a release coating.

[0011]

[12] Another essential object of the present invention is to provide radiation-curable silicone compositions containing Type I photoinitiators and having improved properties.

[13] Another essential object of the present invention is to provide radiation-curable silicone compositions containing Type I photoinitiators and having improved properties in terms of conversion and / or reaction kinetics.

[0012]

[14] Another essential object of the present invention is to provide a radiation-curable silicone composition containing a Type I photoinitiator in which the decomposition products of the photoinitiator are less toxic and / or less likely to migrate through the coating.

[0013]

[15] Another essential object of the present invention is to provide compounds which can be used as radical photoinitiators in radiation-curable compositions.

[16] Another essential object of the present invention is to provide compounds which can be used as radical photoinitiators and which are soluble in silicone compositions, and preferably rapidly soluble in silicone compositions. [Means for solving the problem]

[0014]

[17] Among other objectives, these are: a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b.Formula (I)

[0015] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is

[0016] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 It is preferably a linear or branched C4-C alkyl group. 13 alkyl group, and even more preferably a linear or branched C9 alkyl group. and at least one radical photoinitiator B, which is a compound of the formula This is achieved by the present invention, which first relates to a radiation-curable silicone composition X comprising:

[0017]

[18] The radical photoinitiator B makes it possible to obtain a silicone composition X having good properties in terms of conversion and reaction kinetics. Furthermore, the use of the radical photoinitiator B makes it possible to prepare silicone release coatings having good properties. The radical photoinitiator B also makes it possible to make a good cure of the silicone composition X.

[0018]

[19] Additionally, decomposition products from radical photoinitiator B are less likely to migrate than existing commercially available photoinitiators.

[20] The radical photoinitiator B also has good solubility in silicones. Therefore, it is possible to use the pure photoinitiator and dilute it directly in organopolysiloxane A. Advantageously, the radical photoinitiator B can be dissolved in organopolysiloxane A for less than 15 hours, or less than 10 hours, or less than 5 hours, or less than 2 hours. For example, the solubility can be determined by adding between 1.5 and 3 parts by weight of the radical photoinitiator B to 100 parts by weight of organopolysiloxane A.

[0019]

[21] Another advantage of the radical photoinitiator B is the transparency of the elastomer obtained after curing of the silicone composition X.

[22] The present invention also relates to the use of the silicone composition X described in this application for the preparation of a silicone elastomer that can be used as a release coating on a substrate.

[0020]

[23] The present invention also relates to silicone elastomers obtained by curing the silicone composition X described in this application.

[24] The present invention also provides a method for preparing a coating on a substrate, comprising the steps of: applying a silicone composition X described herein; curing the composition by electron beam or photon irradiation, preferably by exposure to an electron beam, gamma radiation, or radiation having a wavelength between 200 nm and 450 nm, in particular ultraviolet radiation; The present invention relates to a method comprising the steps of:

[0021]

[25] The present invention also relates to a coated substrate obtainable by this method.

[26] The present invention also relates to the use of composition X according to the invention for the preparation of silicone elastomer products by additive manufacturing processes.

[0022]

[27] The present invention also relates to a compound represented by formula (I):

[0023] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is,

[0024] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is a linear or branched C2-C 18 It is an alkyl group, preferably a linear or branched C4-C 13 is preferably a linear or branched C9 alkyl group. The present invention relates to a compound of the formula:

[0025]

[28] The present invention also relates to the use of the compounds defined in the present application as radical photoinitiators.

[0026] definition

[29] In the present application, the term "radiation-curable silicone composition" is understood to mean a silicone composition comprising at least one organopolysiloxane that is curable by electron beam or photon irradiation. Electron beam irradiation includes exposure to an electron beam. Photon irradiation includes exposure to radiation having a wavelength between 200 nm and 450 nm, in particular ultraviolet radiation, or exposure to gamma radiation.

[0027]

[30] "(Meth)acrylate" is understood to mean a methacrylate group or an acrylate group.

[31] "Alkyl" is understood to mean a linear or branched alkyl group. The alkyl group preferably contains 1 to 6 carbon atoms.

[0028]

[32] "Alkylene" is understood to mean a divalent linear or branched alkyl group. The alkylene group preferably contains between 1 and 6 carbon atoms, more preferably between 1 and 4 carbon atoms.

[0029]

[33] "Heteroalkylene" is understood to mean a divalent linear or branched heteroalkyl group. The heteroalkyl group preferably contains between 1 and 6 carbon atoms and between 1 and 3 heteroatoms selected from the group consisting of O, N, and S, where N and S can be optionally oxidized. The heteroatoms can be located at any position of the heteroalkyl group, either internally or at one end.

[0030]

[34] In this application, all percentages are given as weight percent unless otherwise stated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031]

[35] Curable silicone composition X

[36] The present invention provides, first, a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b.Formula (I)

[0032] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is,

[0033] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 It is preferably a linear or branched C4-C alkyl group. 13 alkyl group, and even more preferably a linear or branched C9 alkyl group. and at least one radical photoinitiator B, which is a compound of the formula The present invention relates to a radiation-curable silicone composition X comprising:

[0034]

[37] According to one embodiment, silicone composition X is curable by photon irradiation, preferably by exposure to radiation having a wavelength between 200 nm and 450 nm, in particular ultraviolet radiation.

[0035]

[38] According to one embodiment, the radiation curable silicone composition X has a viscosity between 50 and 2500 mPa.s, preferably between 100 and 1500 mPa.s, so that it can be used with the coating tool used to prepare the silicone release coating.

[0036]

[39] All viscosities mentioned in this specification correspond to the magnitude of the dynamic viscosity at 25° C., which means the dynamic viscosity measured in a manner known per se using a Brookfield viscometer at a shear rate gradient low enough that the measured viscosity is independent of the rate gradient.

[0037]

[40] Organopolysiloxane A

[41] According to the invention, the inventive curable silicone composition X comprises at least one organopolysiloxane A which contains at least one (meth)acrylate group, preferably at least two (meth)acrylate groups.

[0038]

[42] As representatives of the (meth)acrylate functional groups carried by the silicone that are most particularly suitable for the invention, mention may in particular be made of derivatives of acrylates, methacrylates, (meth)acrylate ethers and (meth)acrylate esters, linked to the polysiloxane chain by Si-C bonds.

[0039]

[43] According to one embodiment, the organopolysiloxane A is a) a compound represented by the following formula (IV): R a Z b SiO (4-a-b) / 2 (IV) (In the formula, The R symbols are the same or different, and each is a linear or branched C1-C 18 Alkyl groups, C6-C 12 An aryl group or an aralkyl group, the alkyl group and the aryl group of which are preferably C6-C optionally substituted with a halogen atom. 12 An aryl or aralkyl group, or -OR 5 group (in the formula, R 5 is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, The Z symbol is a monovalent group of formula -y-(Y')n, y is multivalent C1 to C 18represents an alkylene or heteroalkylene group, which may be linear or branched, may be interrupted by one or more cycloalkylene groups, may be extended by C1-C4 divalent oxyalkylene or polyoxyalkylene groups, and which alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups may be substituted by one or more hydroxy groups; Y' represents a monovalent alkenylcarbonyloxy group; n is equal to 1, 2, or 3, a is an integer equal to 0, 1, or 2, b is an integer equal to 1 or 2, and the sum a+b=1, 2, or 3. and at least one unit having the formula: b) optionally, a compound represented by the following formula (V): R a SiO (4-a) / 2 (V) (In the formula, R sign is as defined above in formula (IV), a is an integer equal to 0, 1, 2, or 3) Units with Includes.

[0040]

[44] In the above formulas (IV) and (V), the R symbols are the same or different and each represents a linear or branched C1-C 18 Alkyl group or C6-C 12 Represents an aryl or aralkyl group. Preferably, the R symbol represents a monovalent radical selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl, and phenyl, more preferably, the R symbol represents methyl.

[0041]

[45] Organopolysiloxane A can have a linear, branched, cyclic or network structure. Preferably, organopolysiloxane A has a linear structure. In the case of linear organopolysiloxanes, these are Formula R2SiO 2 / 2, RZSiO 2 / 2 , and ZSiO 2 / 2 "D" siloxy units selected from the units Formula R3SiO 1 / 2 , R2ZSiO 1 / 2 , RZ2SiO 1 / 2 , and ZSiO 1 / 2 "M" siloxy unit selected from units

[0033] The R and Z symbols are as defined above in formula (I).

[0042]

[46] According to one embodiment, in the above formula (IV), the above mentioned Y'-alkenylcarbonyloxy groups include acryloxy [CH2=CH-CO-O-] and methacryloxy [CH2=C(CH3)-CO-O-] groups. Advantageously, organopolysiloxane A contains at least two Y'-alkenylcarbonyloxy groups, preferably at least three Y'-alkenylcarbonyloxy groups.

[0043]

[47] Examples of the y symbol in the unit of formula (IV) include the following groups: -CH2-, -(CH2)2-, -(CH2)3-, -CH2-CH(CH3)-CH2-, -(CH2)3-NR'-CH2-CH2- (R' is a C1 to C6 alkyl group), -(CH2)3-OCH2-, -(CH2)3-[O-CH2-CH(CH3)-] n -(n=1-25), -(CH2)3-O-CH2-CH(OH)(-CH2-), -(CH2)3-O-CH2-C(CH2-CH3)[-(CH2-)]2, -(CH2)3-O-CH2-C[-(CH2)-]3, and -(CH2)2-C6H9(OH)-.

[0044]

[48] ​​Preferably, the organopolysiloxane A is represented by the following formula (VI):

[0045] [ka] (In the formula, R 1 The symbols are the same or different, and each represents a linear or branched C1 to C 18 Alkyl groups, C6-C 12 An aryl group or an aralkyl group, the alkyl group and the aryl group of which are preferably C6-C optionally substituted with a halogen atom. 12 An aryl or aralkyl group, or -OR 5 group (in the formula, R 5 is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, R 2 Sign and R 3 The symbols may be the same or different, and each represents R 1 group or a monovalent group of formula Z=-y-(Y')n, y is multivalent C1 to C 18 represents an alkylene or heteroalkylene group, which may be linear or branched, may be interrupted by one or more cycloalkylene groups, may be extended by C1-C4 divalent oxyalkylene or polyoxyalkylene groups, and which alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups may be substituted by one or more hydroxy groups; Y' represents a monovalent alkenylcarbonyloxy group; n is equal to 1, 2, or 3, a=0 to 1000, b=0 to 500, c=0 to 500, d=0 to 500, and a+b+c+d=0 to 2500, preferably a=0 to 500 and a+b+c+d=0 to 500, At least one R 2 Sign or R 3 When the symbol represents a monovalent group of formula Z, preferably at least two R 2 Sign or R3 The symbol represents a monovalent radical of the formula Z. is equivalent to.

[0046]

[49] According to a preferred embodiment, in the above formula (VI), c = 0, d = 0, a = 1 to 1000, b = 1 to 250, and the symbol R 2 represents a monovalent radical of formula Z, and the symbol R 1 and R 3 has the same meaning as above.

[0047]

[50] Even more preferably, in the above formula (VI), c = 0, d = 0, a = 1 to 500, b = 2 to 100, and the symbol R 2 represents a monovalent radical of formula Z, and the symbol R 1 and R 3 has the same meaning as above.

[0048]

[51] According to one embodiment, the organopolysiloxane A of the present invention is represented by the following formula (VII), (VIII), (IX) or (X):

[0049] [ka] (In the formula, x1 is between 1 and 1000, preferably between 1 and 500; n1 is between 1 and 100, preferably between 2 and 100; x2 is between 1 and 1000, preferably between 1 and 500; n2 is between 1 and 100, preferably between 2 and 100; x3 is between 1 and 1000, preferably x3 is between 1 and 500; x4 is between 1 and 1000, preferably x4 is between 1 and 500).

[0050]

[52] The radiation-curable silicone composition X can contain from 25 to 99.99% by weight of organopolysiloxane A, based on the total weight of the radiation-curable silicone composition X. Preferably, the radiation-curable silicone composition X can contain from 50 to 99.5% of organopolysiloxane A, based on the total weight of the radiation-curable silicone composition X.

[0051]

[53] Naturally, depending on the variant, organopolysiloxane A may be a mixture of compounds meeting the definition of organopolysiloxane A.

[0052]

[54] Radical Photoinitiator B

[55] Radical photoinitiator B is a type I photoinitiator. After photon irradiation, radical photoinitiator B undergoes homolytic cleavage at the α-position of the carbonyl functional group, forming two radical fragments, one of which is a benzoyl radical substituted with an R4 group.

[0053]

[56] Photoinitiator B improves the properties of silicone composition X, especially in terms of conversion and reaction kinetics. Furthermore, radical photoinitiator B makes it possible to obtain good curing of silicone composition X.

[0054]

[57] The silicone composition X may comprise between 0.01 and 20 wt. % of a radical photoinitiator B, based on the total weight of the radiation-curable silicone composition X. Preferably, the radiation-curable silicone composition X comprises between 0.1 and 10 wt. % of a radical photoinitiator B, preferably between 0.1% and 5 wt. %.

[0055]

[58] The radical photoinitiator B is a compound represented by the formula (I)

[0056] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is,

[0057] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 It is preferably a linear or branched C4-C alkyl group. 13 alkyl group, and even more preferably a linear or branched C9 alkyl group. It is a compound of the formula:

[0058]

[59] According to one embodiment, the compound of formula (I) has the formula (II)

[0059] [ka] It is a compound of the formula:

[0060]

[60] According to one embodiment, the compound of formula (I) has the formula (III)

[0061] [ka] It is a compound of the formula:

[0062]

[61] Advantageously, R1 and R2 are, independently of each other, chosen from C1 to C6 alkyl groups. Preferably, R1 and R2 are each a methyl group.

[62] Advantageously, R3 is H.

[0063]

[63] According to one embodiment, n = 0. According to another embodiment, n = 1 or 2 and each R5 group independently represents a C1-C6 alkyl group, preferably a methyl group.

[0064]

[64] According to one embodiment, R9 is a C1-C6 heteroalkylene group, in particular an -O(CH2)2- group, in which the oxygen atom is bonded to the phenyl.

[65] R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 Or C2~C 18 It is preferably a linear or branched C4-C alkyl group. 13 Or C3~C 10 It is preferably an alkyl group, and even more preferably a straight or branched C9 alkyl group.

[0065]

[66] According to one embodiment, R 10 C1 to C are linear or branched 18 An alkyl group, preferably a linear or branched C1-C 13 It is preferably a linear or branched C1-C alkyl group. 10 It is an alkyl group, and even more preferably a linear or branched C1 to C9 alkyl group.

[0066]

[67] According to one embodiment, R 10 C2 to C are linear or branched 18 It is an alkyl group, preferably a linear or branched C2-C 13 It is preferably a linear or branched C2-C alkyl group. 10 It is an alkyl group, and even more preferably a linear or branched C2 to C9 alkyl group.

[0067]

[68] According to one embodiment, R 10 is the branch C1~C 18 An alkyl group, preferably a branched C2-C 17 Or C3~C 18An alkyl group, more preferably a branched C4-C 13 It is preferably an alkyl group, and even more preferably a branched C9 alkyl group.

[0068]

[69] R 10 Examples of groups include a branched C4 alkyl group, a branched C6 alkyl group, a branched C8 alkyl group, a branched C9 alkyl group, a branched C 11 Alkyl groups and branched C 13 Contains an alkyl group.

[0069]

[70] R 10 When R is a branched alkyl group, it may contain a quaternary carbon. Preferably, the quaternary carbon is alpha to the carbonyl, resulting in the use of the term trialkylacetate. The trialkylacetate may be derived from cutting oil. According to one embodiment, R 10 The -(CO)-O- group represents a trialkylacetate, preferably R 10 Branches C4, C6, C8, C9, C 11 , or C 13 Represents an alkyl group.

[0070]

[71] In some cases, R 10 When the -(CO)-O- group represents a trialkylacetate derived from cut oil, several structural isomers are possible. 10 Branches C6, C8, C9, C 11 , or C 13 This may be the case when the group is an alkyl group. 10 can represent a mixture of structural isomers. For example, R 10 When represents a branched C alkyl group, this alkyl group can include different isomers of the following types: -C(CH)-CH(CH)-CH-CH(CH), -C(CH)(CH(CH))-CH-CH(CH), -C(CH)-(CH)-CH, and -C(CH-CH)-(CH)-CH.

[0071]

[72] Other additives

[73] The radiation-curable silicone composition X may also contain other additives, such as polymerization initiators, fillers, virucides, bactericides, anti-wear additives, and pigments (organic or inorganic). Polymerization initiators can include phenol, hydroquinone, 4-OMe-phenol, 2,4,6-tri-tert-butylphenol (BHT), phenothiazine, and nitroxyl radicals, such as (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO).

[0072]

[74] The radiation-curable silicone composition X may also comprise an organic compound C comprising at least one (meth)acrylate functional group. An organic compound C comprising at least one (meth)acrylate functional group is understood to mean any compound comprising one or more (meth)acrylate functional groups. According to one embodiment, the organic compound C comprising at least one (meth)acrylate functional group does not comprise a siloxane structure.

[0073]

[75] Epoxy (meth)acrylates, polyesters of glyceryl (meth)acrylates, urethane (meth)acrylates, polyethers of (meth)acrylates, polyester (meth)acrylates and (meth)acrylate acrylic resins are particularly suitable as organic compounds containing (meth)acrylate functional groups C. Trimethylolpropane triacrylate, tripropylene glycol diacrylate, hexanediol diacrylate and pentaerythritol tetraacrylate are more particularly preferred.

[0074]

[76] Examples of organic compounds C containing (meth)acrylate functional groups are 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 acrylates, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, acrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, alkoxylated hexanediol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, and dipentaerythritol pentaacrylate.

[0075]

[77] The radiation-curable silicone composition X may also contain a filler. The radiation-curable silicone composition X may contain between 0.1 and 40% by weight of a filler, relative to the total weight of the radiation-curable silicone composition X. According to one embodiment, the radiation-curable silicone composition X contains between 20 and 30% by weight of a filler. According to another embodiment, the radiation-curable silicone composition X contains between 0.1 and 10% by weight of a filler. This filler is preferably inorganic. The filler may be a very finely divided product having an average particle size of less than 0.1 μm. The filler may in particular be silica. As regards the silica materials, they may function as reinforcing or semi-reinforcing fillers. The reinforcing silica fillers are selected from colloidal silica, combustion precipitated silica powders, or mixtures thereof. These powders generally have an average particle size of less than 0.1 μm (micrometer) and a particle size of less than 30 μm. 2 / g, preferably 30 to 350m2 / g. Semi-reinforcing silica fillers, such as diatomaceous earth or crushed quartz, can also be used. These silicas can be incorporated as is or after being treated with organosilicon compounds conventionally used for this purpose. Among these compounds are methylpolysiloxanes, such as hexamethyldisiloxane, octamethylcyclotetrasiloxane; methylpolysilazanes, such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane; chlorosilanes, such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane; alkoxysilanes, such as dimethyldimethoxysilane, dimethylvinylmethoxysilane, trimethylmethoxysilane, and mixtures thereof. With respect to non-silica inorganic materials, they can function as semi-reinforcing or packing inorganic fillers. Examples of these non-silica fillers, which can be used alone or in mixtures, are calcium carbonate, which may be surface treated with organic acids or esters of organic acids, calcined clays, titanium dioxide in the rutile form, oxides of iron, zinc, chromium, zirconium, or magnesium, various forms of alumina (hydrated or non-hydrated), boron nitride, lithopone, barium metaborate, barium sulfate, and glass microspheres. These fillers are relatively coarse, with average particle sizes greater than 0.1 μm and generally less than 30 μm in diameter. 2 / g. These fillers may be surface modified by treatment with various organosilicon compounds commonly used for this purpose.

[0076]

[78] According to one embodiment, the radiation-curable silicone composition X comprises: a. at least one organopolysiloxane A containing between 25 and 99.99% by weight of at least one (meth)acrylate group; b. Between 0.01 and 20% by weight of at least one compound of formula (I)

[0077] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is

[0078] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 It is preferably a linear or branched C4-C alkyl group. 13 alkyl group, and even more preferably a linear or branched C9 alkyl group. and a radical photoinitiator B, which is a compound of the formula Includes.

[0079]

[79] Usage

[80] The present invention also relates to the use of the radiation-curable silicone composition X for the preparation of silicone elastomers. These silicone elastomers can have release properties compared to adhesives.

[0080]

[81] The present invention also relates to a method for preparing a silicone elastomer, comprising the step of curing a radiation-curable silicone composition X.

[82] According to one embodiment of the method of the present invention, the curing step is carried out in air or in an inert atmosphere. Preferably, the curing step is carried out in an inert atmosphere.

[0081]

[83] According to one embodiment, the curing step of the method of the present invention is carried out by UV radiation having a wavelength between 200 nm and 450 nm, preferably in an inert atmosphere.

[84] According to another embodiment, the curing step of the method of the present invention is carried out by exposure to electron beam or gamma radiation.

[0082]

[85] Ultraviolet radiation can be emitted by doped or undoped mercury lamps with an emission spectrum spanning 200 nm to 450 nm. Light sources providing spot UV or visible light, such as light-emitting diodes, better known by the acronym "LED", can also be used.

[0083]

[86] According to a preferred embodiment of the invention, the radiation is ultraviolet radiation having a wavelength of less than 400 nanometers. According to a preferred embodiment of the invention, the radiation is ultraviolet radiation having a wavelength of more than 200 nanometers.

[0084]

[87] According to one advantageous embodiment, LED UV lamps are used (UV radiation at 365, 375, 385, and / or 395 nm).

[88] Amounts of UV radiation in the range of about 0.1 to about 0.5 Joules are generally sufficient to effect crosslinking.

[0085]

[89] Irradiation times can be short, typically less than a second, and on the order of a few hundredths of a second for thin coating thicknesses. The resulting cure is excellent, even without any heating.

[0086]

[90] According to one embodiment, the curing step is carried out at a temperature between 10°C and 50°C, preferably between 15°C and 35°C.

[91] Of course, the cure speed can be adjusted by, among other things, the number of UV lamps used, the time of exposure to UV, and the distance between the composition and the UV lamps.

[0087]

[92] The present invention also provides a method for preparing a coating on a substrate, comprising the steps of: applying a radiation-curable silicone composition X onto a substrate; curing the composition by electron beam or photon irradiation, preferably by exposure to an electron beam, gamma radiation, or radiation having a wavelength between 200 nm and 450 nm, in particular ultraviolet radiation; The present invention relates to a method comprising the steps of:

[0088]

[93] The solvent-free composition X of the invention, i.e. undiluted, can be applied using an apparatus capable of depositing small amounts of liquid uniformly. For this purpose, for example, an apparatus known as the "Helio glissant" can be used, which in particular comprises two superimposed rollers. The role of the lower roller, immersed in the coating bath in which the composition is placed, is to impregnate the upper roller with one very thin layer, and the role of the latter, as a consequence, to deposit the desired amount of impregnated composition on the paper, such application being obtained by adjusting the respective speeds of the two rollers rotating in opposite directions relative to each other.

[0089]

[94] Curing to produce a cured product of silicone composition X can be carried out continuously by passing the composition-coated substrate through an irradiation device designed to ensure sufficient residence time for the coated substrate to complete the curing of the coating. Preferably, curing is carried out in the presence of the lowest possible oxygen concentration, typically less than 100 ppm oxygen, preferably less than 50 ppm. Curing is generally carried out in an inert atmosphere, such as nitrogen or argon. The exposure time required to cure silicone composition X is: The particular formulation, type and wavelength of radiation used; Radiation flux, energy flux, the concentration of the radical photoinitiator, and Coating atmosphere and thickness These parameters are well known to those of skill in the art, who know how to accommodate them.

[0090]

[95] The amount of composition X deposited on the substrate can vary, most often from 0.1 to 5 g / m2 of treated surface. 2 These amounts depend on the nature of the substrate and the desired release characteristics. They are most often between 0.5 and 1.5 g / m2 for non-porous substrates. 2 It is between.

[0091]

[96] The method is particularly suitable for preparing silicone release coatings on substrates that are flexible substrates made of fabric, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or nonwoven fiberglass.

[0092]

[97] Flexible substrates coated with silicone release coatings can be used, for example, Paper or polymer films of the polyolefin type (polyvinyl chloride (PVC), polypropylene or polyethylene) or polyester type (polyethylene terephthalate or PET), an adhesive tape having an inner surface coated with a layer of pressure sensitive adhesive and an outer surface including a silicone release coating; Or a polymer film for protecting the adhesive surface of a pressure-sensitive or adhesive-free adhesive component. It is possible.

[0093]

[98] These coatings are particularly suited for their use in the field of release coatings.

[99] The present invention also relates to a coated substrate obtainable according to the method described above. As indicated above, the substrate may be a flexible substrate made of fabric, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or non-woven fiberglass.

[0094]

[0100] The coated substrate may have non-stick, water repellent properties or may have improved surface properties such as slipperiness, stain resistance, or softness.

[0101] Another object of the present invention relates to the use of substrates at least partially coated with the release coating of the present invention in the fields of labels, strips including envelopes, graphic arts, medical and health applications that do not require glue as described above.

[0095]

[0102] The present invention also relates to the use of the composition X of the present invention for the preparation of silicone elastomer products by additive manufacturing processes, also known as 3D printing. This description generally includes the "Standard Terminology for Additive Manufacturing Technologies" designated ASTM F2792-12a. According to this ASTM standard, "3D printer" is defined as "a machine used for 3D printing" and "3D printing" is defined as "the creation of objects by deposition of material using a print head, nozzle, or another printer technology."

[0096]

[0103] Additive manufacturing (AM) is defined as a method of joining materials, usually in layers, to produce objects from 3D model data, as opposed to subtractive manufacturing processes. Synonyms encompassed by 3D printing in relation to 3D printing include additive fabrication, additive processes, additive technology, and layer manufacturing. Additive manufacturing (AM) can also be referred to as rapid prototyping (RP). As used herein, "3D printing" is interchangeable with "additive manufacturing" and vice versa.

[0097]

[0104] Irradiation of the layer of Silicone Composition X as a printing advance causes at least a portion of the composition to rapidly gel during manufacture, thereby allowing each layer to retain its shape without collapsing the printed structure.

[0098]

[0105] Advantageously, the silicone composition X of the invention can be used in 3D printing processes using bath photopolymerization methods (digital light processing, stereolithography), material extrusion, material deposition or inkjet, adapting the viscosity of the silicone composition X to the technique used.

[0099]

[0106] Compounds of formula (I)

[0107] The present invention also relates to a compound of formula (I)

[0100] [ka] (In the formula, R1 and R2 are independently selected from C1-C6 alkyl groups and C3-C7 cycloalkyl groups, or R1 and R2 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl group; R3 is H or a C1-C6 alkyl group, preferably R3 is H; R4 is

[0101] [ka] It is based on each R5 group independently represents a C1-C6 alkyl group; n=0, 1, 2, 3, or 4, preferably n=0, 1, or 2; R9 is a C1-C6 alkylene group or a C1-C6 heteroalkylene group; R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 Or C2~C 18It is preferably a linear or branched C4-C alkyl group. 13 alkyl group, and even more preferably a linear or branched C9 alkyl group.

[0102]

[0108] According to one embodiment, the compound of formula (I) is a compound of formula (II).

[0103] [ka]

[0109] According to one embodiment, the compound of formula (I) is a compound of formula (III).

[0104] [ka]

[0110] Advantageously, R1 and R2 are each independently chosen from C1 to C6 alkyl groups.Preferably, R1 and R2 are each a methyl group.

[0105]

[0111] Advantageously, R3 is H.

[0112] According to one embodiment, n = 0. According to another embodiment, n = 1 or 2 and each R5 group independently represents a C1-C6 alkyl group, preferably a methyl group.

[0106]

[0113] According to one embodiment, R9 is a C1-C6 heteroalkylene group, in particular a -O(CH2)2- group, in which the oxygen atom is bonded to a phenyl.

[0114] R 10 is linear or branched C1-C 18 It is an alkyl group, preferably a linear or branched C2-C 17 Or C2~C 18 It is preferably a linear or branched C4-C alkyl group. 13 Or C3~C 10 It is preferably an alkyl group, and even more preferably a straight or branched C9 alkyl group.

[0107]

[0115] According to one embodiment, R 10 C1 to C are linear or branched 18 An alkyl group, preferably a linear or branched C1-C 13 It is preferably a linear or branched C1-C alkyl group. 10 It is an alkyl group, and even more preferably a linear or branched C1 to C9 alkyl group.

[0108]

[0116] According to one embodiment, R 10 C2 to C are linear or branched 18 It is an alkyl group, preferably a linear or branched C2-C 13 It is preferably a linear or branched C2-C alkyl group. 10 It is an alkyl group, and even more preferably a linear or branched C2 to C9 alkyl group.

[0109]

[0117] According to one embodiment, R 10 is the branch C1~C 18 An alkyl group, preferably a branched C2-C 17 Or C3~C 18 An alkyl group, more preferably a branched C4-C 13 It is preferably an alkyl group, and even more preferably a branched C9 alkyl group.

[0110]

[0118] R 10 Examples of groups include a branched C4 alkyl group, a branched C6 alkyl group, a branched C8 alkyl group, a branched C9 alkyl group, a branched C 11 Alkyl groups and branched C 13 Contains an alkyl group.

[0111]

[0119] R 10 When R is a branched alkyl group, it may contain a quaternary carbon. Preferably, the quaternary carbon is alpha to the carbonyl, resulting in the use of the term trialkylacetate. The trialkylacetate may be derived from cutting oil. According to one embodiment, R 10 The -(CO)-O- group represents a trialkylacetate, preferably R10 Branches C4, C6, C8, C9, C 11 , or C 13 Represents an alkyl group.

[0112]

[0120] In some cases, R 10 When the -(CO)-O- group represents a trialkylacetate derived from cut oil, several structural isomers are possible. 10 Branches C6, C8, C9, C 11 , or C 13 This may be the case when the group is an alkyl group. 10 can represent a mixture of structural isomers. For example, R 10 When represents a branched C alkyl group, this alkyl group can include different isomers of the following types: -C(CH)-CH(CH)-CH-CH(CH), -C(CH)(CH(CH))-CH-CH(CH), -C(CH)-(CH)-CH, and -C(CH-CH)-(CH)-CH.

[0113]

[0121] The compounds of formula (I) may be synthesised according to standard methods used in organic chemistry known to those skilled in the art.

[0122] In particular, compounds of formula (III) can be synthesised from compounds of formula (XI) or from compounds of formula (XII) according to conventional methods used in organic chemistry known to those skilled in the art.

[0114] [ka]

[0123] There are many ways to get it, for example: The corresponding acid R with a compound of formula (XI) in the presence of a strong acid and a solvent allowing the distillation of the azeotrope formed with water. 10 Direct esterification of -COOH, The reaction of the corresponding acid R with a compound of formula (XI) catalyzed, for example, by a β-diketonate of a Group IV metal, in particular zirconium tetraacetylacetonate 10Transesterification of the methyl or ethyl ester of -COO-, The chloride of the corresponding acid R in the presence of triethylamine 10 Reaction of compound (XI) with -COCl, For example, the preparation of a compound of formula (XII) from 2-phenoxyethanol by esterification or transesterification, followed by a Friedel-Crafts reaction with isobutyryl chloride, and chlorination or bromination of the resulting ketone, finally followed by base hydrolysis to form a compound of formula (I).

[0115]

[0124] Use of the compounds of formula (I)

[0125] The present invention also relates to the use of the compounds of formula (I) as defined above as radical photoinitiators, in particular as radical photoinitiators for acrylic silicone compositions.

[0116]

[0126] In fact, the compound of formula (I) of the present invention is soluble in silicones, therefore it can be used as a radical photoinitiator in these compositions without the addition of a solvent.

[0117]

[0127] According to another embodiment, a small amount of a solvent may be used to help make the compound of formula (I) soluble in the silicone composition.

[0128] The present invention also relates to the use of the compounds of formula (I) as defined above as radical photoinitiators in radiation-curable compositions Y comprising at least one radiation-curable unsaturated compound D.

[0118]

[0129] The present invention also provides at least one radiation-curable unsaturated compound D, a photoinitiator which is a compound of formula (I) as described above; The present invention relates to a radiation-curable composition Y comprising:

[0119]

[0130] The radiation-curable unsaturated compound D may contain one or more double bonds which are not part of an aromatic ring.

[0131] According to one embodiment, the radiation-curable unsaturated compound D is a hydrocarbon compound containing one or more double bonds and, optionally, one or more heteroatoms selected from N, P, O, S and F. The unsaturated compound D can be selected, for example, from (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamides, N-substituted (meth)acrylamides, unsaturated acid anhydrides, styrene, alkylstyrenes, divinylbenzene, vinyl ethers, vinyl esters and aryl esters, isocyanurates, N-vinyl heterocycles, and mixtures thereof.

[0120]

[0132] The unsaturated compound D can be a monomer or an oligomer. If the unsaturated compound D is a monomer, it can contain from 2 to 40 carbon atoms and, optionally, from 1 to 20 heteroatoms selected from N, P, O, S, and F. As examples of unsaturated oligomeric compounds D, mention may be made of polymers containing double bonds in the main chain or in pendant chains. Among these polymers, mention may be made of unsaturated polyesters, unsaturated polyamides, and unsaturated polyurethanes.

[0121]

[0133] According to another embodiment, the radiation-curable unsaturated compound D is an organopolysiloxane containing one or more double bonds. Preferably, the radiation-curable unsaturated compound D is an organopolysiloxane containing at least one (meth)acrylate group. The unsaturated compound D can be the organopolysiloxane A described above.

[0122]

[0134] The present invention also relates to the use of a compound of formula (I) as defined above as a radical photoinitiator in a radiation-curable composition Y comprising at least one radiation-curable unsaturated compound D, which is an organopolysiloxane comprising one or more double bonds, preferably comprising at least one (meth)acrylate group.

[0123]

[0135] The radiation curable composition Y can be used in a wide variety of technical fields, for example in printing inks, printing techniques, varnishes, wood coatings, plastic coatings, metal coatings, adhesives and 3D printing. EXAMPLES

[0124]

[0136]

[0137] In the following examples, radiation-curable silicone compositions X of the present invention were prepared using various organopolysiloxanes A and type I radical photoinitiators, the structures of which are shown in the table below. Percentages throughout this specification are expressed as weight percent unless otherwise stated.

[0125]

[0138] Organopolysiloxane A

[0139]

[0126] [Table 1]

[0127]

[0140] Type I radical photoinitiator B of the following formula B1

[0128] [ka] Commercially available compound, CAS number 106797-53-9, trade reference = I2959.

[0129] B2

[0130] [ka] CO-C9H 19 represents a radical derived from neodecanoic acid.

[0131] B3

[0132] [ka] This compound was prepared by esterification of Compound B1 with acetic acid in the presence of a dehydrating agent. Compound B3 is in the form of a recrystallized solid.

[0133]

[0141] Example 1: Synthesis of photoinitiator B2 and solubility study of compounds B2 and B3 in silicone compositions

[0142] A one-neck flask is charged with 1 equivalent of B1, 1 equivalent of neodecanoic acid, and 1 mL of concentrated sulfuric acid per mmol of product. Allow to stir at room temperature under argon for 2 hours. Then react at 120°C under argon for 12 hours.

[0134]

[0143] Once the reaction is complete, 10 times the volume of the reaction medium is added to water and the mixture is extracted three times with n-hexane. The organic phases are then combined, neutralized with sodium carbonate, dried and evaporated. The crude product obtained is then purified on silica gel with a 90 / 10 cyclohexane / ethyl acetate eluent to obtain product B2.

[0135]

[0144] Compound B2 was characterized by infrared and NMR, and the results are shown in Table 2 below.

[0145]

[0146]

[0136] [Table 2]

[0147] The solubility of compounds B2 and B3 in the silicone composition was also tested, and the results are shown in Table 3 below.

[0137]

[0148]

[0138] [Table 3]

[0149] These results demonstrate that the photoinitiators of the present invention are soluble in silicone compositions.

[0139]

[0150] Example 2: Monitoring the polymerization of the acrylic functional groups of acrylic silicones under UV mercury lamps

[0151] The preparation was carried out as follows: the photoinitiator was weighed and introduced into the organopolysiloxane A1, and the whole was stirred until a homogeneous product was obtained (approximately 30 min). The mixture was made based on 2 g of organopolysiloxane A1. The data are expressed in % by weight. The composition is shown in Table 3 below.

[0140]

[0152] The resulting formulation was then cured by UV irradiation with a mercury xenon lamp equipped with a reflector at 365 nm. The output of the UV lamp was 510 mW.cm -2 was set to.

[0141]

[0153] The operation was carried out under air conditions or under laminated conditions to prevent any inhibition of the reactive species by oxygen. When operating under "laminated" conditions, the formulation was placed between two sheets of polypropylene and then between two CaF2 disks.

[0142]

[0154] The polymerization kinetics is monitored using real-time Fourier transform infrared (RT-FTIR, Vertex 70, Brucker Optik). This spectroscopic technique detects the band at 1636 cm, which is characteristic of the C=C bond of the acrylic functional group. -1 It consists of exposing a sample simultaneously to light and infrared light to follow the changes in the IR spectrum during

[0143]

[0155] The conversion of C=C to CC during polymerization was calculated according to the following equation: Conversion (%)=(A0-At) / A0×100, where A0 is the area under the peak before irradiation and At is the area under the peak at each time t during irradiation. -1 This is directly related to the decrease in the area under the peak in

[0144]

[0156] The plot of time allows to get close to not only the final conversion but also other important parameters, such as the maximum conversion rate ((Rp / [M]0) x 100), the latter being determined by the slope of the conversion (%) = f(t) curve at the inflection point.

[0145]

[0157] The results are shown in Table 4 below.

[0158]

[0146] [Table 4]

[0159] These results show that the Type I photoinitiators of the present invention are more efficient in terms of conversion and reaction kinetics than the commercially available photoinitiators.

[0147]

[0160] Example 3: Evaluation of the effectiveness of Type I photoinitiators by monitoring the polymerization of acrylic functional groups of silicones in thin layer applications for non-stick applications

[0161] In the following examples, the silicone composition of the present invention is coated on a flexible substrate and then cured by exposure to radiation. The release performance of the resulting substrate is evaluated. For this purpose, the formulation is prepared as follows: 100 parts by weight of a mixture is prepared containing 70 parts by weight of organopolysiloxane A2 and 30 parts by weight of organopolysiloxane A3. Then, 6.6 mmol of photoinitiator B1, B2, or B3 is added to this mixture (corresponding to about 1.5 parts by weight of photoinitiator B1, 2.5 parts by weight of photoinitiator B2, and 1.8 parts by weight of photoinitiator B3, respectively). After the photoinitiator is completely solubilized, the composition is coated on various substrates using a Mayer rod under the conditions described in the various examples.

[0148]

[0162] Tests performed on substrates coated with silicone release coatings

[0163] Deposition: Verification of silicone deposits coated on surfaces by X-ray fluorescence analysis of silicon (Lab-X 3000, Oxford). The X-ray tube excites the electron shells of silicon atoms, causing the emission of X-rays proportional to the amount of excited silicon. This value or number of counts is converted by calculation (using a standard curve) into the amount of silicone.

[0149]

[0164] Contamination: Qualitative verification of surface polymerization by finger staining method consisting of: Place the silicone coated substrate sample to be inspected on a flat, hard surface. Draw a line with your fingertip while applying moderate but firm pressure, and The resulting lines are visually observed, preferably in oblique light. Differences in surface gloss make the presence of finger marks evident, even if only slightly. The assessment is qualitative. "Stain" is quantified by the following designation: A to D, from best to worst result. A: Very good, no lines left by fingers B: A little better, barely visible lines C: Sharp lines D: Very clear lines and oily appearance of the surface, the product is barely polymerized

[0150]

[0165] Rub Off: Verification of the ability of silicone to adhere to flexible substrates by rubbing back and forth with a finger consisting of:

[0151] Place the silicone coated substrate sample to be tested, silicone side up, on a flat, hard surface. Rub your fingertips back and forth 10 times (over a length of about 10 cm) using moderate but firm pressure. The appearance of the rubbed area is observed visually: rub-off corresponds to the appearance of a fine white powder or small balls rolling under the fingers.

[0152] The evaluation is qualitative. Rub-off is quantified by the following notation: 10: Very good, no rubbing off after 10 rubbings 1: Very bad, some rubbing off on first rub The score corresponds to the number of rubs (1-10) before and after rub-off occurred, ie, a score of 1-10 from poorest to best result.

[0153]

[0166] Dewetting: Evaluation of the degree of polymerization of a silicone layer by evaluating the migration of silicone into an adhesive in contact with the coating using a standardized surface tension test ink. The method is as follows:

[0154] Select a sample of silicone-coated paper of approximately 20 × 5 cm, taken in the unwinding direction (machine direction), to be characterized. The adhesive tape was cut to a length of approximately 15 cm and then placed adhesive side down on the wrinkle-free paper to be inspected and pressure was applied 10 times by running a finger along the length of the adhesive tape (3M "Scotch" tape, reference number 610, width 25 mm); Remove the adhesive tape and place it on a flat surface with the adhesive side facing up. Using a (disposable) cotton swab, place a strip of ink (SHERMAN or FERARINI and BENELI brand inks with a surface tension of approximately 30 dyn / cm and a viscosity of 2-4 mPa / s) on the adhesive part of the tape, extending to a length of approximately 10 cm, and immediately start the timer. When the ink droplet changes appearance, it is considered that the dewetting phase has occurred, and then the timer is stopped. The application of ink to the adhesive part of the tape must be done within 2 minutes of coating with silicone. If the result is less than 10 seconds, the silicone transfers to the adhesive and polymerization is not complete. A score of 0 to 10 was given depending on the time elapsed in seconds before the dewetting phenomenon was observed. If the result obtained is 10 seconds, then the polymerization is considered complete, in this case a score of 10 is obtained, which means the result is very good, The score obtained and the ink used (name, brand, surface tension, viscosity) are noted.

[0155]

[0167] Extractables: A measure of the amount of silicones that are not grafted into the network formed during polymerization. These silicones are extracted from the film immediately after removal from the machine by immersing the sample in MIBK (methyl isobutyl ketone) for a minimum of 24 hours. This is measured by flame atomic absorption spectrometry.

[0156]

[0168] Preparation of multi-layered products without the need for glue

[0169] To form a multi-layer product, a TESA 7475 standard adhesive substrate (substrate=PET-adhesive=acrylic) is laminated to the silicone liner prepared above (=substrate coated with silicone coating obtained by UV curing). Tensile tests are performed to determine the peel force before and after aging, as well as the subsequent adhesion and loop tack values. These tests are described below.

[0157]

[0170] Tests performed on the resulting multi-layered product

[0171] Residual Adhesion (or "SubAd"): A measurement verifying the remaining tack of an adhesive (TESA 7475) in contact with a silicone coating according to the FINAT 11 (FTM 11) test known to those skilled in the art, where the reference specimen was PET and the adhesive remained in contact with the silicone surface being tested for 1 day at 70°C.

[0158] The results were expressed as the remaining adhesive strength (%) of the reference tape, CA=(Fm2 / Fm1)×100(%) (where: Fm2 = average tape peel force after 20 hours of contact with silicone substrate; Fm1 = average tape peel force without contact with silicone substrate) A stickiness of over 90% is desirable.

[0159]

[0172] Peel force: Peel force measurements are performed with TESA 7475 standard adhesive. Test pieces of the multilayer product (adhesive in contact with silicone surface) are kept at 23°C for 1 day and 70°C for 1 day under the required pressure conditions according to the FINAT 10 test, and then tested at slow peel speed according to the FINAT 3 test (FTM 3) known to those skilled in the art.

[0160]

[0173] The peel force is expressed in cN / inch and is measured using a dynamometer after pressing the sample either at room temperature (23° C.) or at a higher temperature for accelerated aging tests (usually 70° C.).

[0174] The formulations tested and the test results are shown in Table 5 below.

[0161]

[0175]

[0162] [Table 5]

[0176] The stain, rub-off, and dewetting results of the type I photoinitiator of the present invention indicate good polymerization of the acrylic silicone formulation. This good polymerization is also reflected in the low level of extractables. The resulting film has the expected non-stick properties. In particular, the residual adhesion rate is better than that of the comparative example.

[0163]

[0177] Thus, the Type I photoinitiators of the present invention can be used to prepare release systems. Specific embodiments of the present invention are as follows. [1] a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b.Formula (I) [ka] (In the formula, R 1 and R 2 are independent of each other, C 1 ~C 6 Alkyl groups and C 3 ~C 7 cycloalkyl groups, or R 1 and R 2 together with the carbon atom to which they are attached, 3 ~C 7 Forming a cycloalkyl group, R 3 is H or C 1 ~C 6 is an alkyl group, preferably R 3 is H, R 4 teeth,

change

change

change

[10] Formula (I)

change

change

[11] The following formula (II)

change

[10] ) The compound according to

[10] ,

[12] The following formula (III)

change

[10] ) The compound according to

[10] or

[11] , wherein the compound is a compound represented by the formula:

[13] Use of a compound according to any one of

[10] to

[12] as a radical photoinitiator, in particular as a radical photoinitiator in a radiation-curable composition Y comprising at least one radiation-curable unsaturated compound D.

[14] The use according to

[13] , wherein the radiation-curable unsaturated compound D is a hydrocarbon compound containing one or more double bonds and, optionally, one or more heteroatoms selected from N, P, O, S and F.

[15] The use according to

[13] , wherein the radiation-curable unsaturated compound D is an organopolysiloxane containing one or more double bonds.

[16] as radical photoinitiators in a radiation-curable composition Y comprising at least one radiation-curable unsaturated compound D,

change

change

Claims

1. a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b. Formula (I) 【Chemistry 1】 (In the formula, R １ and R ２ are, independently of each other, C １ ~C ６ Alkyl group and C ３ ~C ７ cycloalkyl groups, or R １ and R ２ together with the carbon atom to which they are attached, ３ ~C ７ Forming a cycloalkyl group, R ３ is H or C １ ~C ６ is an alkyl group, R ４ teeth, 【Chemistry 2】 It is based on Each R ５ The groups are independently １ ~C ６ represents an alkyl group, n=0, 1, 2, 3, or 4; R ９ is C １ ~C ６ Alkylene group or C １ ~C ６ is a heteroalkylene group, R １０ is a linear or branched C １ ~C １８ is an alkyl group) and at least one radical photoinitiator B, which is a compound of the formula A radiation-curable silicone composition X comprising:

2. The compound of formula (I) is represented by formula (II) 【Chemistry 3】 (In the formula, R １ , R ２ , R ３ , and R ４ is as defined in claim 1) 2. The silicone composition of claim 1, wherein the compound is

3. The compound of formula (I) is represented by formula (III) 【Chemistry 4】 (In the formula, R １０ is as defined in claim 1) 2. The silicone composition of claim 1, wherein the compound is

4. The organopolysiloxane A is a) a compound represented by the following formula (IV): R ａ Z ｂ SiO （４－ａ－ｂ）／２ (IV) (In the formula, The R symbols are the same or different, and each is a linear or branched C １ ~C １８ Alkyl group, optionally substituted C ６ ~C １２ An aryl group or an aralkyl group, or -OR ５ group (in the formula, R ５ is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, The Z symbol is a monovalent group of formula -y-(Y')n, y is a multivalent C １ ~C １８ represents an alkylene or heteroalkylene group, which may be linear or branched and may be interrupted by one or more cycloalkylene groups; １ ~C ４ and may be extended by a divalent oxyalkylene or polyoxyalkylene group, said alkylene, heteroalkylene, oxyalkylene, and polyoxyalkylene groups being optionally substituted with one or more hydroxy groups; Y' represents a monovalent alkenylcarbonyloxy group; n is equal to 1, 2, or 3; a is an integer equal to 0, 1, or 2, b is an integer equal to 1 or 2, and the sum a+b=1, 2, or 3. and at least one unit of b) optionally, a compound represented by the following formula (V): R ａ SiO （４－ａ）／２ (V) (In the formula, The R symbol is as defined above in formula (IV), a is an integer equal to 0, 1, 2, or 3. Units with The silicone composition X according to any one of claims 1 to 3, comprising:

5. Use of a silicone composition X according to any one of claims 1 to 4 for the preparation of a silicone elastomer which can be used as a release coating on a substrate.

6. A silicone elastomer obtained by curing the silicone composition X according to any one of claims 1 to 4.

7. 1. A method for preparing a coating on a substrate, comprising: applying a silicone composition X according to any one of claims 1 to 4; curing the composition by electron beam or photon irradiation; A method comprising:

8. A coated substrate obtainable by the method of claim 7.

9. 5. Use of composition X according to any one of claims 1 to 4 for the preparation of a silicone elastomer product by an additive manufacturing process.

10. Formula (I) 【Chemistry 5】 (In the formula, R １ and R ２ are, independently of each other, C １ ~C ６ Alkyl group and C ３ ~C ７ cycloalkyl groups, or R １ and R ２ together with the carbon atom to which they are attached, ３ ~C ７ Forming a cycloalkyl group, R ３ is H or C １ ~C ６ is an alkyl group, R ４ teeth, 【Chemistry 6】 It is based on Each R ５ The groups are independently １ ~C ６ represents an alkyl group, n=0, 1, 2, 3, or 4; R ９ is C １ ~C ６ Alkylene group or C １ ~C ６ is a heteroalkylene group, R １０ is a linear or branched C2-C １８ is an alkyl group) Compound.

11. The following formula (II) 【Chemistry 7】 (In the formula, R １ , R ２ , R ３ , and R ４ is as defined in claim 10. The compound according to claim 10, characterized in that it is

12. The following formula (III): 【Chemistry 8】 (In the formula, R １０ is as defined in claim 10.

12. The compound according to claim 10 or 11, characterized in that it is a compound of the formula:

13. 13. Use of a compound according to any one of claims 10 to 12 as a radical photoinitiator.

14. 14. The use according to claim 13, wherein the radiation-curable unsaturated compound D is a hydrocarbon compound containing one or more double bonds and, optionally, one or more heteroatoms selected from N, P, O, S and F.

15. 14. The use according to claim 13, wherein the radiation-curable unsaturated compound D is an organopolysiloxane containing one or more double bonds.

16. as radical photoinitiators in a radiation-curable composition Y comprising at least one radiation-curable unsaturated compound D of formula (I) 【Chemistry 9】 (In the formula, R １ and R ２ are, independently of each other, C １ ~C ６ Alkyl group and C ３ ~C ７ cycloalkyl groups, or R １ and R ２ together with the carbon atom to which they are attached, ３ ~C ７ Forming a cycloalkyl group, R ３ is H or C １ ~C ６ is an alkyl group, R ４ teeth, 【Chemistry 10】 It is based on Each R ５ The groups are independently １ ~C ６ represents an alkyl group, n=0, 1, 2, 3, or 4; R ９ is C １ ~C ６ Alkylene group or C １ ~C ６ is a heteroalkylene group, R １０ is a linear or branched C １ ~C １８ is an alkyl group) The use of a compound of the formula The use, wherein the unsaturated compound D is an organopolysiloxane containing one or more double bonds.

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