RADIATION CURABLE SILICONE COMPOSITIONS CONTAINING RELEASE CONTROL ADDITIVES -

Abstract

The present invention relates to a photocurable silicone composition comprising a release control additive which is an organopolysiloxane resin containing Si-OH groups. In particular, the present invention relates to a silicone composition comprising at least one organopolysiloxane A containing at least one (meth)acrylate group, at least 25% by weight of an organopolysiloxane resin B containing Si-OH groups, and at least one radical photoinitiator C. The composition of the present invention may be used to form a release coating.

Description

[Technical field]

[0001] [1] The present invention relates to a radiation-curable silicone composition comprising a release control additive which is an organopolysiloxane resin containing Si-OH groups. In particular, the present invention relates to a silicone composition comprising at least one organopolysiloxane A containing at least one (meth)acrylate group, at least 25% by weight of an organopolysiloxane resin B containing Si-OH groups, and optionally at least one radical photoinitiator C. The composition of the present invention may be used to form a release coating. [Background technology]

[0002] [2] The use of plastic films as substrate materials for the application of silicone coatings to form release coatings (non-stick coatings) requires appropriate technology. In fact, most plastic films are sensitive to heat. Therefore, the combined effect of the tensile forces and the temperature to which the film is subjected when coating the silicone layer and drying in a thermo oven leads to dimensional deformation of the film. The technology of curing functional silicone oils under irradiation, especially under ultraviolet (UV) light, makes it possible not to use high temperatures and thus to crosslink the release layer without affecting the substrate. In addition, this technology has the advantage of achieving high productivity without large energy consumption and without the use of solvents. Plastic substrates are the material of choice for many applications and their use is constantly increasing.

[0003] [3] The preparation of silicone release coatings is generally carried out as follows: the silicone composition is applied to the substrate in an industrial coating device equipped with rollers operating at very high speeds (e.g. 600 m / min). The silicone composition applied to the substrate 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 may in particular be laminated with an adhesive, since the silicone release coating makes it possible to facilitate the removal of adhesive materials reversibly adhered to these substrates. These silicone liners may therefore be used in the fields of self-adhesive labels, strips including envelopes, graphic arts, medicine and hygiene.

[0004] [4] Silicone compositions used to form release coatings are generally cured (crosslinked) under irradiation, particularly UV or visible light emitted by doped or undoped mercury vapor lamps with emission spectra ranging from 200 nm to 450 nm. Light sources such as light-emitting diodes (commonly known by the acronym "LED") that emit spot UV or visible light can also be used.

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

[0006] [6] The free radical polymerization of molecules with acrylic functional groups under irradiation, especially under UV irradiation, is well documented. The same applies to silicone oils with acrylic functional groups, which are prepared by various means. One of the most important features of these silicone acrylate compositions is the control of the adhesion of the cured silicone composition to adhesives depending on the intended use, especially depending on the substrate material used. Therefore, various compositions have been developed for radiation-curable silicone acrylates that allow the adhesion to adhesives to be controlled depending on the desired level.

[0007] [7] For example, document FR2632960 describes polysiloxanes with (meth)acrylate groups linked by SiC groups. By adjusting the chain length and acrylate level of the polysiloxane oil, it is possible to control the adhesion of these UV-curing systems. However, this approach requires the synthesis of new siloxane oils for each target release level, making adjustments difficult to achieve.

[0008] [8] There is therefore a need to develop a silicone acrylate composition that allows the level of release to the adhesive of the coating obtained after curing of the silicone composition to be easily controlled depending on the intended application.

[0009] [9] In this context, the present invention aims to meet at least one of the following objectives:

[10] One essential object of the present invention is to provide a radiation curable silicone composition that includes a release control additive ("RCA") and that may be used to form a release coating.

[0010]

[11] Another essential object of the present invention is to provide radiation-curable silicone compositions having improved properties.

[12] Another essential object of the present invention is to provide a radiation-curable silicone composition in which the adhesive properties of the coating obtained after curing of the silicone composition can be controlled.

[0011]

[13] Another essential object of the present invention is to provide a radiation-curable silicone composition that is easy to prepare industrially and economically.

[14] Another essential object of the present invention is to provide a radiation-curable silicone composition that can be used without solvent, due to environmental considerations.

[0012]

[15] Another essential object of the present invention is to provide a radiation curable silicone composition that has a viscosity that is compatible with the coating tools used to prepare the silicone release coating.

[0013]

[16] Another essential objective of the present invention is to provide a radiation-curable silicone composition that makes it possible to obtain a coating with a "smooth" release profile, meaning that there is little or no noise when pulling, i.e. the release force remains stable throughout the step of peeling the composite (separating the adhesive from the silicone liner).

[0014]

[17] Another essential object of the present invention is to provide a radiation-curable silicone composition which makes it possible to obtain coatings having a release force that is stable over time.

[18] Another essential object of the present invention is to provide a radiation-curable silicone composition which makes it possible to obtain a coating having a stable release force at any release rate. Summary of the Invention

[0015]

[19] In particular, these objects are achieved firstly by the present invention, which relates to a radiation-curable silicone composition X comprising: a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b. at least 25% by weight of an organopolysiloxane resin B containing Si-OH groups; c. Optionally, at least one radical photoinitiator C.

[0016]

[20] The fact of using at least 25% by weight of organopolysiloxane resin B containing Si-OH groups makes it possible to control the adhesion to adhesives of the coating obtained after curing of silicone composition X. It is therefore possible to use radiation-curable silicone composition X to form release coatings on substrates. The non-stickiness of the free outer surface of the silicone coating is expressed and verified by the peel force from a standardized adhesive. The peel force may in particular be measured by the FINAT 3 (FTM 3) test, which is well known to those skilled in the art. This test makes it possible to determine the peel force (also called peel force) required to peel the adhesive from the laminated coated substrate (also called silicone liner). The composition according to the invention makes it possible to easily control these peel forces, and therefore the release properties to adhesives, depending on the intended application, in particular by adjusting the resin level in the composition.

[0017]

[21] Furthermore, the coating obtained after curing the composition of the present invention has a "smooth" release profile in which the release force remains stable throughout the composite peel step (separating the adhesive from the silicone liner). Additionally, these benefits are obtained while maintaining good properties in other areas (smear, rub-off, and residual adhesion).

[0018]

[22] The present invention also relates to the use of radiation-curable silicone composition X for the preparation of a silicone elastomer which can be used as a release coating on a substrate.

[23] 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; and - curing said composition by electron or photon irradiation, preferably by exposure to electron beams, by exposure to gamma radiation or by exposure to radiation having a wavelength between 200 nm and 450 nm, in particular by exposure to ultraviolet radiation.

[0019]

[24] Substrates that can be coated are, for example, flexible substrates made of textiles, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or nonwoven glass fiber.

[0020]

[25] The present invention also relates to a coated substrate obtainable by the above process.

[26] The present invention also provides a premix for a silicone composition, comprising: a. 20-40 wt. % of at least one organopolysiloxane A containing at least one (meth)acrylate group; b. 30 to 50% by weight of an organopolysiloxane resin B containing Si-OH groups; and c. 10 to 30% by weight of an organic compound D containing a (meth)acrylate functional group The present invention relates to a premix comprising:

[0021] definition

[27] In the present application, the term "radiation-curable silicone composition" is understood to mean a silicone composition containing at least one organopolysiloxane that is crosslinkable by electron or light irradiation. Electron irradiation includes electron beams. Light irradiation includes exposure to radiation having a wavelength of 200 nm to 450 nm, in particular ultraviolet light, or exposure to gamma rays.

[0022]

[28] "Release control additive" is understood to mean an adhesion control agent capable of modifying the adhesive or release properties of the coating obtained after curing of the silicone composition X to adhesives.

[0023]

[29] Throughout this specification, organopolysiloxanes are conventionally described using the usual notation in which the letters M, D, T and Q are used to designate the various siloxyl units. As a reference, NOLL "Chemistry and technology of silicones", chapter 1.1, pp.1-9, Academic Press, 1968-2nd edition can be mentioned. In this notation, the silicon atom of the siloxyl unit is covalently bonded to one (M), two (D), three (T) or four (Q) oxygen atoms. If an oxygen atom is shared between two silicon atoms, it is counted as 1 / 2 and is not written in the shorthand. However, if the oxygen atom belongs to a hydroxyl group bonded to a silicon atom, this chemical functionality may be indicated in brackets in the shorthand. By default, the remaining bonds of the silicon atom are considered to be bonded to carbon atoms. Generally, the hydrocarbon groups bonded to silicon by C-Si bonds are not written and in most cases correspond to alkyl groups, e.g. methyl groups. For example, the abbreviated formula T(OH)2 represents a unit in which a silicon atom is bonded to three oxygen atoms containing two hydroxyl groups, i.e., the alkyldihydroxysiloxyl unit RSi(OH)2O 1 / 2 where R can represent various saturated or unsaturated hydrocarbon groups, in particular aromatic, optionally substituted with heteroatoms. The meaning of R is defined herein.

[0024]

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

[31] "Organopolysiloxane resin" is understood to mean an organopolysiloxane compound containing at least one T unit and / or at least one Q unit.

[0025]

[32] "Alkylene" is understood to mean a linear or branched divalent alkyl group. The alkylene group preferably contains 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms.

[0026]

[33] "Heteroalkylene" is understood to mean a linear or branched divalent heteroalkyl group. The heteroalkyl group preferably contains 1 to 18 carbon atoms and 1 to 6 heteroatoms selected from the group consisting of O, N and S, where N and S may be optionally oxidized. The heteroatoms may be located at any position, internal position or at one end of the heteroalkyl group.

[0027]

[34] "Cycloalkylene" is understood to mean a divalent cycloalkyl group. The cycloalkyl group preferably contains 3 to 12 carbon atoms, preferably 3 to 6 carbon atoms.

[0028]

[35] "Solvent" is understood to mean an organic solvent. Organic solvents are well known to those skilled in the art. Examples of organic solvents include alkanes (such as pentane or hexane), aromatics (such as benzene, toluene, or xylene), ethers (such as diethyl ether or tetrahydrofuran), alcohols (such as methanol, ethanol, propanol, or butanol), chloroform, acetone, acetonitrile, pyridine, ethyl acetate, dimethylformamide, and dimethylsulfoxide. "Solvent-free composition" is understood to mean a composition that contains less than 10% by weight of solvent, preferably less than 5% by weight, and more preferably less than 1% by weight.

[0029]

[36] In this application, all percentages are given by weight unless otherwise specified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030]

[37] Radiation-curable silicone composition X is a. at least one organopolysiloxane A containing at least one (meth)acrylate group; b. at least 25% by weight of an organopolysiloxane resin B containing Si—OH groups, and c. Optionally, at least one radical photoinitiator C Includes.

[0031]

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

[0032]

[39] This radiation-curable silicone composition X can be used as is without the need for dilution with a solvent. Thus, according to one embodiment, the radiation-curable silicone composition X is solvent-free.

[0033]

[40] The radiation-curable silicone composition X may have a viscosity of 200 to 2500 mPa·s, preferably 500 to 1500 mPa·s, which allows the composition to be used in coating tools used to prepare silicone release coatings.

[0034]

[41] All viscosities mentioned in this specification correspond to the dynamic viscosity magnitude called "Newton" at 25° C. Said viscosity means the dynamic viscosity measured in a manner known per se using a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0035]

[42] Organopolysiloxane A

[43] According to the invention, the curable silicone composition X according to the invention comprises at least one organopolysiloxane A containing at least one (meth)acrylate group, preferably at least two (meth)acrylate groups.

[0036]

[44] Representative of the (meth)acrylate functional groups contained in the silicones which are particularly suitable for the present invention are, in particular, derivatives of acrylates, methacrylates, (meth)acrylate ethers and (meth)acrylate esters which are linked to the polysiloxane chain by Si-C bonds.

[0037]

[45] According to one embodiment, the organopolysiloxane A is a) Formula (I): R a Z b SiO (4-a-b) / 2 (I) [In the formula, the symbols R are identical or different and each represents a linear or branched C1-C18 alkyl group, a C6-C12 aryl group or an aralkyl group, said alkyl and aryl groups being optionally preferably halogen atoms or -OR 5 Group(R 5 is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, - the symbol Z is a monovalent radical of the formula -y-(Y')n (In the formula, - y represents a polyvalent C1-C18 alkylene or heteroalkylene group, which may be linear or branched and is optionally interrupted by one or more cycloalkylene groups and optionally extended by a C1-C4 oxyalkylene or polyoxyalkylene divalent group, and which alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups are optionally substituted by one or more hydroxy groups, - Y' represents a monovalent alkenylcarbonyloxy group; - n equals 1, 2, or 3) and - a is an integer equal to 0, 1, or 2, and b is an integer equal to 1 or 2, with the sum a+b=1, 2, or 3, b) optionally, a compound of formula (II): R a SiO (4-a) / 2 (II) (In the formula, the symbol R is as defined above in formula (I), - a is an integer equal to 0, 1, 2 or 3 Includes.

[0038]

[46] In the above formulae (I) and (II), the symbols R are the same or different and each represents a linear or branched C1-C18 alkyl group, or a C6-C12 aryl or aralkyl group. Preferably, the symbol R represents a monovalent group selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl, and more preferably, the symbol R represents methyl.

[0039]

[47] Organopolysiloxane A can have a linear, branched, cyclic or network structure. Preferably, organopolysiloxane A has a linear structure. In the context of organopolysiloxanes, these can consist essentially of: - Formula R2SiO 2 / 2 , RZSiO 2 / 2 and Z2SiO 2 / 2 a "D" siloxyl unit selected from the units - Formula R3SiO 1 / 2 , R2ZSiO 1 / 2 , RZ2SiO 1 / 2 , and ZSiO 1 / 2 "M" siloxyl unit selected from the units (- the symbols R and Z are as defined above in formula (I)).

[0040]

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

[0041]

[49] Examples of the symbol y in the unit of formula (I) include the following groups: -CH2-; -(CH2)2-; -(CH2)3-; -CH2-CH(CH3)-CH2-; -(CH2)3-NR'-CH2-CH2- (wherein R' is a C1 to C6 alkyl group); -(CH2)3-OCH2-; -(CH2)3-[O-CH2-CH(CH3)-]n- (wherein n=1 to 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)-.

[0042]

[50] Preferably, the organopolysiloxane A corresponds to formula (III) below:

[0043] [ka]

[0044] [In the formula, - Symbol R 1 are the same or different, each of which is a linear or branched C1-C 18 Alkyl groups, C6-C 12 represents an aryl or aralkyl group, the alkyl and aryl groups being optionally preferably halogen atoms, or -OR 5 Group(R 5 is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, - Symbol R 2 and R 3 are the same or different, and each R 1 A group or a monovalent group of the formula Z=-y-(Y')n (In the formula, - y represents a polyvalent C1-C18 alkylene or heteroalkylene group, said alkylene and heteroalkylene groups may be linear or branched, optionally interrupted by one or more cycloalkylene groups and optionally extended by a C1-C4 oxyalkylene or polyoxyalkylene divalent group, said alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups being optionally substituted by one or more hydroxy groups, - Y' represents a monovalent alkenylcarbonyloxy group; - n equals 1, 2, or 3) represents one of the following: 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 symbol R 2 or R 3 represents a monovalent radical of formula Z, preferably with at least two symbols R 2 or R 3 represents a monovalent group of formula Z.

[0045]

[51] According to a preferred embodiment, in the above formula (III), - c=0, d=0, a=1 to 1000 (preferably a=1 to 499), b=1 to 250, and the symbol R 2 represents a monovalent group of formula Z, and the symbol R 1 and R 3 has the same meaning as above.

[0046]

[52] More preferably, in the above formula (III), - c=0, d=0, a=1 to 500 (preferably a=1 to 498), b=2 to 100, and the symbol R 2 represents a monovalent group of formula Z, and the symbol R 1 and R 3 has the same meaning as above.

[0047]

[53] According to one embodiment, in the above formula (III), - c = 0, d = 0, a = 1 to 1000 (preferably a = 1 to 499), b = 1 to 250, symbol R 2 and R 3 represents a monovalent group of formula Z, and the symbol R 1 has the same meaning as above.

[0048]

[54] According to one embodiment, the organopolysiloxane A according to the invention corresponds to any of the following formulae (IV), (V), (VI) or (VII):

[0049] [ka]

[0050] (In the formula, - x1 is 1 to 1000, preferably 1 to 500 or 1 to 499, - n1 is 1 to 100, preferably n1 is 2 to 100, - x2 is 1 to 1000, preferably 1 to 500 or 1 to 499, - n2 is 1 to 100, preferably, n2 is 2 to 100; - x3 is 1 to 1000, preferably 1 to 500, - x4 is 1 to 1000, preferably x4 is 1 to 500).

[0051]

[55] The radiation-curable silicone composition X may contain 25 to 75% of the organopolysiloxane A based on the total weight of the radiation-curable silicone composition X.

[56] The molar content of (meth)acrylate functional groups in organopolysiloxane A may be greater than or equal to 30 mmol / 100 g of organopolysiloxane A, preferably 35 to 250 mmol / 100 g of organopolysiloxane A.

[0052]

[57] Organopolysiloxane A may have a molar content of (meth)acrylate functional groups of 60 mmol / 100 g of organopolysiloxane A or more, preferably 65 to 250 mmol / 100 g of organopolysiloxane A.

[0053]

[58] The radiation-curable silicone composition X can comprise a single organopolysiloxane A or a mixture of organopolysiloxanes A, for example having different acrylate contents. When the radiation-curable composition X comprises a mixture of organopolysiloxanes A, several embodiments are possible.

[0054]

[59] Organopolysiloxane A is, for example, - at least one organopolysiloxane having a high molar content of (meth)acrylate functional groups (for example, 30 or 60 mmol / 100 g of organopolysiloxane or more), and - it may contain at least one organopolysiloxane having a low molar content of (meth)acrylate functional groups (for example less than 30 or 60 mmol / 100 g of organopolysiloxane, respectively);

[0055]

[60] According to a first embodiment, the organopolysiloxane A is a1. at least one organopolysiloxane A1 containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of 30 mmol / 100 g of organopolysiloxane A1 or more, preferably 35 to 250 mmol / 100 g of organopolysiloxane A1; and a2. At least one organopolysiloxane A2 containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of less than 30 mmol / 100 g of organopolysiloxane A2, preferably 1-30 mmol / 100 g of organopolysiloxane A2, and more preferably 15-25 mmol / 100 g of organopolysiloxane A2.

[0056]

[61] According to a second embodiment, the organopolysiloxane A is a1. at least one organopolysiloxane A1' containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of 60 mmol / 100 g of organopolysiloxane A1' or more, preferably 65 to 250 mmol / 100 g of organopolysiloxane A1', and a2. At least one organopolysiloxane A2' containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of less than 60 mmol / 100 g of organopolysiloxane A2', preferably 1-60 mmol / 100 g of organopolysiloxane A2', and more preferably 15-55 mmol / 100 g of organopolysiloxane A2'.

[0057]

[62] The content of (meth)acrylate functional groups is expressed in mmol / 100 g of organopolysiloxane A, A1, A1', A2, or A2'.

[63] Organopolysiloxanes A1, A1', A2, and A2' may be as described above for organopolysiloxane A.

[0058]

[64] The combination of two organopolysiloxanes A1 and A2, or A1' and A2', with different molar acrylate contents makes it possible to control the adhesion of the coating obtained after curing to the adhesive. Indeed, by adjusting the amount of organopolysiloxane A2 or A2' in silicone composition X, it is possible to control the adhesion of the coating obtained after curing to the adhesive, depending on the desired application.

[0059]

[65] Silicone composition X may contain 0.1 to 10% by weight, preferably 1 to 8% by weight, of organopolysiloxane A2 or A2', based on the total weight of radiation-curable silicone composition X.

[0060]

[66] Thus, silicone composition X is - 25 to 74.9% by weight, preferably 25 to 65% by weight, of organopolysiloxane A1 or A1', relative to the total weight of the radiation-curable silicone composition X, and Based on the total weight of the radiation-curable silicone composition X, the composition may contain 0.1 to 10% by weight, preferably 1 to 8% by weight, of organopolysiloxane A2 or A2'.

[0061]

[67] The proportion of organopolysiloxane A2 or A2' compared to organopolysiloxane A1 or A1' may be expressed as the mass ratio A2:A1 or A2':A1'. Preferably, this ratio is from 1:65 to 1:2, more preferably from 1:50 to 1:3, and even more preferably from 1:40 to 1:5.

[0062]

[68] Organopolysiloxane resin B containing Si-OH groups

[69] The organopolysiloxane resin B containing Si-OH groups makes it possible to control the adhesion of the coating obtained after curing to the adhesive. It also makes it possible to obtain a coating with a "smooth" peel profile. This means that the peel force remains stable throughout the step of peeling the composite (separating the adhesive from the silicone liner).

[0063]

[70] According to one embodiment, the radiation-curable silicone composition X comprises resin B in an amount of 25 to 60% by weight, preferably 25 to 50% by weight.

[71] The organopolysiloxane resin B is a well-known, commercially available branched organopolysiloxane oligomer or polymer. This resin contains at least one T unit and / or at least one Q unit. This resin also contains in its structure at least one OH functional group bonded to a silicon atom, and thus a Si-OH group.

[0064]

[72] The OH functional groups can be contained in the T and / or Q units. Thus, the organopolysiloxane resins B useful in the present invention contain T(OH) and / or Q(OH) units (where T(OH)=(OH)R 4 SiO 2 / 2 , Q(OH)=(OH)SiO 3 / 2 and R 4 R may include a linear or branched C1-C6 alkyl group, a C2-C4 alkenyl group, a phenyl group, and a 3,3,3-trifluoropropyl group. 4 Examples of the group include an alkyl group, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and an n-hexyl group. 4 The group is a methyl radical.

[0065]

[73] Examples of organopolysiloxane B resins include MDT resins, DT resins and MQ resins.

[74] MDT resin is M unit = (R 4 )3SiO 1 / 2 , D=(R 4 )2SiO 2 / 2 , and T units = R 4 SiO 3 / 2 The T units may also contain OH groups. Thus, MDT resins are T(OH)=(OH)R 4 SiO 2 / 2 In these formulas, R 4 The radicals are as defined above.

[0066]

[75] DT resin is a resin with D units = (R 4 )2SiO 2 / 2 and T units = R 4 SiO 3 / 2 and some of the T units contain OH groups. Therefore, DT resins contain T(OH)=(OH)R 4 SiO 2 / 2 In these formulas, R 4 The radicals are as defined above.

[0067]

[76] MQ resins are made up of M units = (R 4)3SiO 1 / 2 , and Q units = SiO 4 / 2 Some of the Q units contain OH groups. Therefore, MQ resins are Q(OH)=(OH)SiO 3 / 2 In these formulas, R 4 The radicals are as defined above.

[0068]

[77] According to a preferred embodiment, R 4 The groups are independently selected from linear or branched C1-C6 alkyl groups and the 3,3,3-trifluoropropyl group.

[78] Preferably, resin B is an MDT or MQ resin.

[0069]

[79] When resins having Q units are used, the molar ratio M / (T+Q) of these resins may be comprised between 0.5 and 1.5, preferably between 0.7 and 1.2.

[80] The OH functional group content of resin B may be 0.2-5 wt.%. According to one embodiment, the OH functional group content is at least 0.5 wt.%. Preferably, the OH functional group content is 0.5-5 wt.%, more preferably 0.6-4.5 wt.%, even more preferably 0.7-4 wt.%. The OH functional group content is expressed as the weight of OH functional groups relative to the total weight of resin B.

[0070]

[81] Resin B generally has an average molecular weight comprised between 500 and 10,000 g / mol, preferably between 1,000 and 6,000 g / mol.

[82] The radiation-curable silicone composition X can contain a single resin B or a mixture of several resins B.

[0071]

[83] Radical Photoinitiator C

[84] The radiation-curable silicone composition may contain a radical photoinitiator C. The radical photoinitiator C is included in particular when the composition is curable by photon irradiation under radiation having a wavelength of 200 nm to 450 nm, in particular UV radiation.

[0072]

[85] Radical photoinitiators C release free radicals into the medium under the influence of absorption of incident light energy. These radicals act as initiators for the free radical polymerization of (meth)acrylic functional groups.

[0073]

[86] As a radical photoinitiator, after exposure to ultraviolet (UV) light, - Aromatic ketones undergoing homolytic cleavage at the α-position of the carbonyl function, resulting in the formation of two radical fragments, one of which is a benzoyl radical (Type I photoinitiators), or - Aromatic ketones that form free radicals by transferring to an excited state through the loss of a hydrogen from a hydrogen donor molecule (more commonly called a "co-initiator"), leading to the formation of an inactive cetyl radical and the corresponding donor-derived initiator radical (Type II photoinitiators).

[0074]

[87] These photoinitiators are well known to those skilled in the art. Examples of Type I photoinitiators include α-hydroxy ketones, benzoin ethers, and α-amino aromatic ketones.

[0075]

[88] Examples of Type II photoinitiators include isopropylthioxanthone (ITX), benzophenone, and camphorquinone (CQ). Examples of coinitiators include aromatic amines such as phenyltetrazolethiol, tris(trimethylsilyl)silane, and ethyl dimethylaminobenzoate (EDB).

[0076]

[89] Examples of photoinitiators are described, for example, in patents FR 2 632 960, EP 0 940 422-B1, EP 0 979 851-B1, EP 1 544 232-B1, and EP 1 411 095 A2. A conventionally used photoinitiator is Irgacure® 1173 (formerly Darocur® 1173) from BASF.

[0077]

[90] Examples of radical photoinitiators C include, in particular, the following products: isopropylthioxanthone; benzophenone; camphorquinone; 9-xanthenone; anthraquinone; 1,4-dihydroxyanthraquinone; 2-methylanthraquinone; 2,2'-bis(3-hydroxy-1,4-naphthoquinone); 2,6-dihydroxyanthraquinone; 1-hydroxycyclohexyl phenyl ketone; 1,5-dihydroxyanthraquinone; 1,3-diphenyl-1,3-propanedione; 5,7-dihydroxyflavone; dibenzoyl peroxide; 2-benzoylbenzoic acid; 2-hydroxy-2-methylpropiophenone; 2-phenylacetophenone. ;Anthrone;4,4'-Dimethoxybenzoin;Phenanthrenequinone;2-Ethylanthraquinone;2-Methylanthraquinone;2-Ethylanthraquinone;1,8-Dihydroxyanthraquinone;Dibenzoyl peroxide;2,2-Dimethoxy-2-phenylacetophenone;Benzoin;2-Hydroxy-2-methylpropiophenone;Benzaldehyde;4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-methylpropyl) ketone;Benzoylacetone;Ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate;and mixtures thereof.

[0078]

[91] As commercial examples of radical photoinitiators C according to the invention, mention may also be made, among benzophenone derivatives, of the products Esacure® TZT, Speedcure® MBP, Omnipol® BP; and, among thioxanthone derivatives, of the products Irgacure® 907, Omnipol® TX, and Genopol® TX-1.

[0079]

[92] According to one particular embodiment, the radical photoinitiator C is selected from the group consisting of benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone and its derivatives, formic acid benzoyl esters, camphorquinone, benzil, phenanthrenequinone, coumarin and ketocoumarin, and mixtures thereof. Examples of these radicals are described, for example, in application WO2017 / 109116.

[0080]

[93] Benzophenone derivatives refer to substituted benzophenones and polymers of benzophenone.

[94] Thioxanthone derivatives refer to substituted thioxanthones, and anthraquinone derivatives refer to substituted anthraquinones, particularly anthraquinone sulfonic acid and acrylamide substituted anthraquinones.

[0081]

[95] Benzoyl formates include benzoylmethyl formates, which are optionally difunctional.

[96] Useful examples of radical photoinitiators C are also described in patent application EP 0007508. According to one embodiment, the radical photoinitiator C is selected from the group consisting of the following derivatives: 2,2-dimethyl-propionyldiphenylphosphine oxide, 2,2-dimethyl-heptanoyl-diphenylphosphine oxide, 2,2-dimethyl-octanoyl-diphenylphosphine oxide, 2,2-dimethyl-nonanoyl-diphenylphosphine oxide, methyl 2,2-dimethyl-octanoyl-phenylphosphineate, 2-methyl-2-ethylhexanoyl-diphenylphosphine oxide, 1-methyl-1-cyclohexanecarbonyl-diphenylphosphine oxide, 2,6-dimethylbenzoyl-diphenylphosphine oxide, 2,6-dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, methyl 2,6-dimethoxybenzoyl-phenylphosphineate, 2, 4,6-trimethylbenzoyl-diphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphineate, 2,3,6-trimethylbenzoyl-diphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethoxybenzoyl-diphenylphosphine oxide, 2,4,6-trichlorobenzoyl-diphenylphosphine oxide, 2-chloro-6-methyl-thio-benzoyl-diphenylphosphine oxide, methyl-2,4,6-trimethyl-benzoyl-naphthylphosphineate, 1,3-dimethoxynaphthalene-2-carbonyl-diphenylphosphine oxide, and 2,8-dimethoxynaphthalene-1-carbonyl-diphenylphosphine oxide.

[0082]

[97] According to a particularly preferred embodiment, the radical photoinitiator C is ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate (CAS number 84434-11-7).

[0083]

[98] Preferably, the effective amount of the radical photoinitiator C is from 0.1% to 20% by weight, preferably from 0.1 to 10% by weight, and more preferably from 0.1 to 5% by weight, based on the total weight of the radiation-curable silicone composition X or the functionalized organopolysiloxane A.

[0084]

[99] Organic compound D

[0100] The radiation-curable silicone composition X may comprise an organic compound D that comprises at least one (meth)acrylate functional group.

[0085]

[0101] The radiation-curable silicone composition X can contain one organic compound D or several different organic compounds D.

[0102] The presence of an organic compound D comprising at least one (meth)acrylate functional group makes it possible to obtain, after curing of the silicone composition X, a coating having a release force towards adhesives that is stable over time.

[0086]

[0103] Advantageously, the radiation-curable silicone composition X comprises from 0.1 to 30% by weight, preferably from 1 to 25% by weight, more preferably from 3 to 22% by weight of an organic compound D containing a (meth)acrylate functional group.

[0087]

[0104] An organic compound D 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 D comprising at least one (meth)acrylate functional group does not comprise a siloxane structure.

[0088]

[0105] Particularly suitable organic compounds D containing (meth)acrylate functional groups are epoxidized (meth)acrylates, (meth)acryloglyceropolyesters, (meth)acrylourethanes, (meth)acrylopolyethers, (meth)acrylopolyesters and (meth)acryloacrylics. Particularly preferred are trimethylolpropane triacrylate, tripropylene glycol diacrylate, hexanediol diacrylate and pentaerythritol tetraacrylate.

[0089]

[0106] Examples of organic compounds D containing (meth)acrylate functional groups include: ethylhexyl acrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, isodecyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, cyclohexyl acrylate, isooctyl acrylate, tridecyl acrylate, isobornyl acrylate, caprolactone acrylate, alkoxylated phenol acrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, 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, ditrimethylolpropane tetraacrylate, and dipentaerythritol pentaacrylate.

[0090]

[0107] Other Additives

[0108] The radiation-curable silicone composition X may also contain other additives such as polymerization inhibitors, fillers, virucides, bactericides, anti-wear additives, pigments (organic or inorganic), etc. Polymerization inhibitors include phenol, hydroquinone, 4-OMe-phenol, 2,4,6-tritertiary-butylphenol (BHT), phenothiazine, and nitroxyl radicals such as (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO).

[0091]

[0109] According to one embodiment, the radiation-curable silicone composition X is a. at least one organopolysiloxane A containing at least one (meth)acrylate group, which has the following formula (III):

[0092] [ka]

[0093] [In the formula, - Symbol R 1 are the same or different, each of which is a linear or branched C1-C 18 Alkyl groups, C6-C 12 represents an aryl or aralkyl group, the alkyl and aryl groups being optionally preferably halogen atoms, or -OR 5 Group(R 5 is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, - Symbol R 2 and R 3 are the same or different, and each R 1 A group or a monovalent group of the formula Z=-y-(Y')n (In the formula, - y represents a polyvalent C1-C18 alkylene or heteroalkylene group, said alkylene and heteroalkylene groups may be linear or branched, optionally interrupted by one or more cycloalkylene groups and optionally extended by a C1-C4 oxyalkylene or polyoxyalkylene divalent group, said alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups being optionally substituted by one or more hydroxy groups, - Y' represents a monovalent alkenylcarbonyloxy group; - n equals 1, 2, or 3) represents one of the following: - a=0-500, b=0-500, c=0-500, d=0-500, and a+b+c+d=0-500, - At least one symbol R 2 or R 3 represents a monovalent radical of formula Z, preferably with at least two symbols R 2 or R 3 represents a monovalent radical of formula Z. Organopolysiloxane A, which corresponds to b. at least 25% by weight of an organopolysiloxane resin B containing Si-OH groups; c. Optionally, at least one radical photoinitiator C Includes.

[0094]

[0110] Premix for silicone compositions

[0111] The radiation-curable silicone composition X can be prepared by mixing the various components.

[0095]

[0112] Nevertheless, when the radiation-curable silicone composition X comprises an organic compound D comprising at least one (meth)acrylate functional group, it is also possible to prepare the radiation-curable silicone composition X by using a premix comprising: a. 20-40 wt. % of at least one organopolysiloxane A containing at least one (meth)acrylate group; b. 30 to 50% by weight of an organopolysiloxane resin B containing Si-OH groups; and c. 10-30% by weight of an organic compound D containing a (meth)acrylate functional group.

[0096]

[0113] This premix can then be diluted with organopolysiloxane A to form radiation-curable silicone composition X. This premix can have a viscosity of 500 to 2000 mPa·s, which allows it to be easily diluted with organopolysiloxane A. This makes it possible to easily form radiation-curable silicone composition X having a viscosity that is compatible with a coating tool. In addition, by using this premix, the concentration of organopolysiloxane resin B in radiation-curable silicone composition X can be easily controlled, and therefore the adhesion of the coating obtained after curing to an adhesive can be easily controlled.

[0097]

[0114] This premix also makes it possible to obtain a silicone composition with better homogeneity, which is important when used in coating equipment with rollers that operate at very high speeds.

[0098]

[0115] Thus, one object of the present invention is to provide a premix for a silicone composition, comprising: a. 20-40 wt. % of at least one organopolysiloxane A containing at least one (meth)acrylate group; b. 30 to 50% by weight of an organopolysiloxane resin B containing Si-OH groups; and c. 10 to 30% by weight of an organic compound D containing a (meth)acrylate functional group It is a premix comprising:

[0099]

[0116] Compounds A, B and D are as described above for the radiation-curable silicone composition X.

[0100]

[0117] Radiation-curable silicone composition X1 or X1'

[0118] Another object of the present invention is to provide a radiation-curable silicone composition X1, a.1) at least one organopolysiloxane A1 containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of 30 mmol / 100 g of organopolysiloxane A1 or more, preferably 35 to 250 mmol / 100 g of organopolysiloxane A1, a.2) at least one organopolysiloxane A2 which contains at least one (meth)acrylate group and which has a molar content of (meth)acrylate functional groups of less than 30 mmol / 100 g of organopolysiloxane A2, preferably between 1 and 30 mmol / 100 g of organopolysiloxane A2, and more preferably between 15 and 25 mmol / 100 g of organopolysiloxane A2, b. at least one organopolysiloxane resin B containing Si-OH groups; c. Optionally, at least one radical photoinitiator C The radiation-curable silicone composition X1 comprises:

[0101]

[0119] Another object of the present invention is to provide a radiation-curable silicone composition X1', a.1) at least one organopolysiloxane A1' containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of 60 mmol / 100 g of organopolysiloxane A1' or more, preferably 65 to 250 mmol / 100 g of organopolysiloxane A1', a.2) at least one organopolysiloxane A2' containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of less than 60 mmol / 100 g of organopolysiloxane A2', preferably between 1 and 60 mmol / 100 g of organopolysiloxane A2', and further preferably between 15 and 55 mmol / 100 g of organopolysiloxane A2', b. at least one organopolysiloxane resin B containing Si-OH groups; c. Optionally, at least one radical photoinitiator C The radiation-curable silicone composition X1' comprises:

[0102]

[0120] These radiation-curable silicone compositions X1 and X1' can contain resin B in an amount of 0.5 to 60% by weight, and preferably 10 to 50% by weight.

[0121] According to one embodiment, the radiation-curable silicone composition X1 contains 0.1 to 10% by weight, preferably 2 to 8% by weight, of organopolysiloxane A2.

[0103]

[0122] The silicone composition X1 is - 25 to 74.9% by weight, preferably 25 to 65% by weight, of organopolysiloxane A1, based on the total weight of the radiation-curable silicone composition X1, and The radiation-curable silicone composition X1 may contain 0.1 to 10% by weight, preferably 1 to 8% by weight, of organopolysiloxane A2, based on the total weight of the composition X1.

[0104]

[0123] According to one embodiment, the radiation-curable silicone composition X1' contains 0.1 to 10% by weight, preferably 2 to 8% by weight, of organopolysiloxane A2'.

[0124] The silicone composition X1' is - 25 to 74.9% by weight, preferably 25 to 65% by weight, of organopolysiloxane A1', relative to the total weight of the radiation-curable silicone composition X1', and The radiation-curable silicone composition X1' can contain 0.1 to 10% by weight, preferably 1 to 8% by weight, of organopolysiloxane A2', relative to the total weight of the composition X1'.

[0105]

[0125] The proportion of organopolysiloxane A2 or A2' compared to organopolysiloxane A1 or A1' may be expressed as the mass ratio A2:A1 or A2':A1'. Preferably, this ratio is from 1:65 to 1:2, preferably from 1:50 to 1:3, more preferably from 1:40 to 1:5.

[0106]

[0126] These radiation-curable silicone compositions X1 and X1' may further comprise an organic compound D containing a (meth)acrylate functional group.

[0127] Compounds A1, A1′, A2, A2′, B, C and D are as described above for the radiation-curable silicone composition X.

[0107]

[0128] These radiation-curable silicone compositions X1 and X1' may also be used in applications similar to those described below for radiation-curable silicone composition X.

[0129] The combination of two organopolysiloxanes A1 and A2, or A1' and A2', with different molar acrylate contents makes it possible to control the adhesion of the coating obtained after curing. In fact, by adjusting the amount of organopolysiloxane A2 or A2' in silicone composition X1 or X1', it is possible to control the adhesion of the coating obtained after curing depending on the desired application.

[0108]

[0130] Purpose

[0131] 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 for adhesives.

[0109]

[0132] The present invention also relates to a method for preparing a silicone elastomer comprising the step of curing a radiation-curable silicone composition X.

[0133] 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.

[0110]

[0134] According to one embodiment, the curing step of the method according to the invention is carried out by UV light having a wavelength between 200 nm and 450 nm, preferably in an inert atmosphere.

[0135] According to another embodiment, the curing step of the method according to the invention is carried out by exposure to electron beam or gamma radiation.

[0111]

[0136] Ultraviolet light may be emitted by doped or undoped mercury vapor lamps with emission spectra ranging from 200 nm to 450 nm. Light sources such as light-emitting diodes (commonly known by the acronym "LED") that emit spot UV or visible light can also be used.

[0112]

[0137] According to a preferred embodiment of the invention, the radiation is ultraviolet light having a wavelength of less than 400 nanometers. According to a preferred embodiment of the invention, the radiation is ultraviolet light having a wavelength of greater than 200 nanometers.

[0113]

[0138] According to one advantageous embodiment, LED UV lamps are used (UV emission of 365, 375, 385 and / or 395 nm).

[0139] A UV dose in the range of about 0.1 to about 0.5 Joules is generally sufficient to induce crosslinking.

[0114]

[0140] Irradiation times can be short, typically less than a second, and on the order of a few hundredths of a second for small coating thicknesses. The crosslinking obtained is good even in the absence of any heating.

[0141] 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.

[0115]

[0142] Of course, the cure speed can be adjusted by, among other things, the number of UV lamps used, the exposure time to UV, and the distance between the composition and the UV lamps.

[0143] 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 to a substrate; and - curing said composition by electron or photon irradiation, preferably by exposure to electron beams, by exposure to gamma radiation or by exposure to radiation having a wavelength between 200 nm and 450 nm, in particular by exposure to ultraviolet radiation.

[0116]

[0144] The solvent-free composition X according to the invention, i.e. the stock solution, can be applied using a device suitable for uniformly depositing small amounts of liquid. For this purpose, for example, a device known as "Helio glissant" can be used, which in particular comprises two superimposed rollers. The role of the lower roller, which is immersed in the coating tank in which the composition is located, is to impregnate the upper roller with a thin layer, and the role of the latter is then to deposit on the paper the desired amount of the composition with which the upper roller is impregnated, such dosing being obtained by adjusting the respective speeds of the two rollers which rotate in opposite directions relative to each other.

[0117]

[0145] Crosslinking leading to the curing of silicone composition X may be carried out continuously by passing the composition-coated substrate through an irradiation device designed to ensure sufficient residence time on the coated substrate for the curing of the coating to be completed.Preferably, curing is carried out in the presence of as low a concentration of oxygen as possible, typically less than 100 ppm, 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 varies depending on factors such as: - the specific formulation, type and wavelength of radiation used; - dose flow rate, energy flux, - the concentration of the radical photoinitiator, and - the atmosphere and the thickness of the coating. These parameters are well known to those skilled in the art, who will know how to adapt them.

[0118]

[0146] The amount of composition X deposited on the substrate is variable and in most cases is between 0.1 and 5 g / m2 of treated surface. 2 These amounts depend on the nature of the substrate and the desired release properties. For non-porous substrates, these amounts are in the range of 0.5 to 1.5 g / m 2 It is.

[0119]

[0147] The method is particularly suitable for preparing silicone release coatings on substrates that are flexible substrates made of textiles, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or non-woven glass fibers.

[0120]

[0148] Flexible substrates having a silicone release coating may be, for example: - Paper or polymeric film based on polyolefin (polyvinyl chloride (PVC), polypropylene, polyethylene) or polyester (polyethylene terephthalate, i.e. PET), - adhesive tapes, the inner surface of which is coated with a pressure-sensitive adhesive layer and the outer surface of which is provided with a silicone release coating; - Or polymeric films to protect the adhesive surface of self-adhesive components or pressure-sensitive adhesives.

[0121]

[0149] These coatings are particularly suitable for use in the release coating field.

[0150] The present invention also relates to a coated substrate obtained according to the above-mentioned method. As indicated above, the substrate may be a flexible substrate made of textile, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or non-woven glass fiber.

[0122]

[0151] The coated substrates have non-stick and water repellent characteristics or allow for improved surface properties such as slipperiness, stain resistance, or softness.

[0152] Another object of the invention relates to the use of substrates, at least partially coated with a release coating according to the invention as defined above, in the fields of self-adhesive labels, strips including envelopes, graphic arts, medicine and hygiene. EXAMPLES

[0123]

[0153] In the following examples, various organopolysiloxanes A, resins B, radical photoinitiators C, and organic compounds D are used to prepare radiation-curable silicone compositions X according to the present invention. The structures of those compounds are shown in the table below. Throughout the specification, % is expressed by weight %, unless otherwise stated.

[0124]

[0154] Organopolysiloxane A

[0155]

[0125] [Table 1]

[0126]

[0156] Organopolysiloxane resin B containing Si-OH groups B1: MQ resin in which some of the Q units contain OH groups, the OH functional group content being 2% by weight and the average molar mass being 5500 g / mol B2: MQ resin in which some of the Q units contain OH groups, the OH functional group content is 3% by weight and the average molar mass is 6000 g / mol B3: an MQ resin in which some of the Q units contain OH groups, the OH functional group content is 1.6% by weight, and the M / Q ratio is 1.1 B4: MDT resin in which some of the T units contain OH groups, the OH functional group content is 0.8% by weight and the average molar mass is 1000-6000 g / mol.

[0127]

[0157] Radical photopolymerization initiator C having the following formula: C1:

[0128] [ka]

[0129] C2:

[0130] [ka]

[0131]

[0158] organic compound D D1: Hexanediol diacrylate D2: Tripropylene glycol diacrylate D3: Trimethylolpropane triacrylate

[0159] The composition is prepared as follows: since the resin is diluted with an organic solvent such as toluene, a solvent exchange with the organopolysiloxane A1 is first carried out, the organic solvent is then evaporated and then the other components are added.

[0132]

[0160] When the composition includes organic compound D, a premix according to the present invention is prepared. Since the resin is diluted with an organic solvent such as toluene, a solvent exchange with organic compound D is first performed. The organic solvent is then evaporated and the mixture is diluted with organopolysiloxane A1 to form the premix. The other ingredients are then added to the premix to form the composition.

[0133]

[0161] The compositions tested are shown in Tables 2 and 3.

[0162]

[0134] [Table 2]

[0135]

[0163]

[0136] [Table 3]

[0137]

[0164] Testing performed on silicone release coated substrates

[0165] Following the coating test on the pilot line, a peel coating test was carried out. For the test, the above formulation is coated using the coating pilot line. The machine speed is set at 100 m / min and the lamp power at 150 W / cm. The coated substrate is PP, on which 0.9 g / m 2 + / -0.1g / m 2 A silicone acrylate layer of 10 ...

[0138]

[0166] Deposits: Silicon X-ray fluorescence analysis (Lab-X 3000, Oxford) verifies the silicone deposits coated on the surface. The X-ray tube excites the electron shells of the silicon atoms, causing the emission of X-rays proportional to the amount of silicon excited. This value or number of counts is converted by calculation (using a standard curve) to the amount of silicon.

[0139]

[0167] Smear: Qualitative verification of surface polymerization by finger smear method consisting of: - Place the silicone coated substrate sample to be examined on a flat, hard surface; - Draw lines using moderate but clear pressure with your fingertip; - The resulting lines are inspected visually, preferably in oblique light. In this way, the presence of even the slightest finger marks can be detected by differences in the surface gloss. The assessment is qualitative. The "smear" is quantified using the following notation: A: Very good, no finger marks left B: Somewhat poor, barely visible lines C: Clear lines D: Very clear lines, oily surface, little polymerisation of product That is, rate the results from best to worst, A to D.

[0140]

[0168] Rub Off: Verify the ability of silicone to adhere to a flexible substrate by rubbing back and forth with a finger as follows: Place a sample of the silicone-coated substrate to be tested, silicone side up, on a flat, hard surface; With moderate but definite pressure, rub your fingertips back and forth 10 times (approximately 10 cm long); The appearance of the rubbed area is visually assessed. Rub-off corresponds to the appearance of a fine white powder or small balls that roll under the fingers. The assessment is qualitative. Rub-off is quantified using the following notation: 10: Very good, no rub-off even after rubbing back and forth 10 times 1: Very bad, rubs off after one rub The score corresponds to the number of back and forth rubs (1-10) required before rub-off occurs, i.e., a score of 1 to 10, ranging from the weakest to the best results.

[0141]

[0169] Preparation of self-adhesive multi-layer articles

[0170] Standard adhesive substrates TESA 7475 (acrylic) and TESA 4651 (rubber) are laminated to the silicone liner (=substrate with silicone coating obtained by crosslinking under UV) prepared above to form a multi-layer article. Tensile tests are carried out to determine the peel force and residual adhesion values ​​before and after aging. These tests are described below.

[0142]

[0171] Tests performed on the resulting multilayer article

[0172] Residual Adhesion or "SubAd": A measurement verifying the residual 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 is PET and the adhesive is left in contact with the silicone surface being tested for 1 day at 70°C. The results are expressed as the residual adhesive force % of the reference tape: CA=(Fm2 / Fm1)×100(%). where Fm2 = average tape peel force after 20 hours of contact with the silicone substrate; Fm1 = average tape peel force without contact with silicone substrate. Greater than 90% adhesion is desired.

[0143]

[0173] Peel: Peel force measurements are carried out using standard adhesives TESA 7475 and TESA 7476. Test pieces of the multilayer article (adhesive in contact with silicone surface) were stored for 1 day at 23° C., 1 day at 70° C. and 7 days at 40° C. under the pressure conditions required according to the FINAT 10 test. They were then tested at a slow peel rate according to the FINAT 3 test (FTM 3) known to those skilled in the art (Peel-Finat 3 in the table) or at a fast peel rate according to the FINAT 4 test at room temperature (RT) or at 40° C. (Peel-Finat 4).

[0144]

[0174] The peel force is expressed in cN / inch and is measured using a dynamometer after pressing the sample at room temperature (23°C) or at an elevated temperature for accelerated aging tests (typically 70°C).

[0145]

[0175] Noise-zippy release: Perception of detachment in terms of force oscillation parameters: noisy, zippy (as opposed to "smooth"). A quiet, jerk-free separation is desired.

[0146]

[0176] The test results are shown in the table below.

[0177]

[0147] [Table 4]

[0148]

[0178] The results in Table 4 show that the compositions according to the invention containing resin B containing Si-OH groups (Examples 1-2) are more stable at high speeds of pulling and give better results in terms of less noisy-zippy peeling than the comparative composition without resin (Comparative Example 2). These results also show that the addition of resin B containing Si-OH groups makes it possible to control the peel force of the resulting coating. In fact, it is observed that the peel force measured according to the FINAT 3 test after 1 day at 23° C. is comparable for the compositions without resin, whether or not they contain an organic compound containing acrylate functional groups (Comparative Examples 1 and 3), while the measured peel force is greater in the compositions according to the invention containing resin B containing Si-OH groups (Examples 1-2). Moreover, the other evaluated properties smear, rub-off and residual adhesion are well preserved in the compositions according to the invention.

[0149]

[0179]

[0150] [Table 5]

[0151]

[0180] The results in Table 5 show that compositions according to the invention comprising a resin B and an organic compound D containing acrylate functional groups make it possible to obtain coatings with stable release forces after aging (Examples 3 to 6 and 16). In addition, the compositions according to the invention are more stable in pulling at high speeds and give better results in terms of noise-zippy release than the comparative composition without resin (Comparative Example 2). Furthermore, depending on the resin used, it is also possible to control the release force of the coatings obtained (Examples 4 to 6). These results also show that it is possible to use several organopolysiloxanes A with different acrylate contents.

[0152]

[0181]

[0153] [Table 6]

[0154]

[0182] The results in Table 6 show that the compositions according to the invention (Examples 7-10) make it possible to obtain coatings with a stable release force after aging, similar to the resin-free compositions (Comparative Examples 1-2). In addition, the results show that it is possible to modify the release force of the coatings obtained by changing the resin content in the composition (Examples 7-10) and to use different radical photoinitiators C (Examples 10 and 11). Finally, the compositions according to the invention give better results in terms of noise-zippy release than the comparative composition without resin (Comparative Example 2).

[0155]

[0183]

[0156] [Table 7]

[0157]

[0184] The results in Table 7 show that it is possible to modify the release force of the resulting coating by varying the resin content in the composition (Examples 12-13 and 14-15) and by varying the amount of acrylate with a low acrylate molar content (Compound A2, see Examples 12-13 vs. 14-15). In addition, the compositions according to the invention give better results in terms of zippy release than the comparative composition without resin (Comparative Example 2).

Claims

1. A radiation-curable silicone composition X, a. at least one organopolysiloxane A containing at least one (meth)acrylate group, which has the following formula (III): 【Chemistry 1】 [In the formula, - Symbol R １ are the same or different, each of which is a linear or branched C １ ~C １８ Alkyl group, C ６ ~C １２ an aryl or aralkyl group, the alkyl and aryl groups being optionally substituted, or -OR ５ Group (R ５ is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, - Symbol R ２ each represents a monovalent group of formula Z=-y-(Y')n, - Symbol R ３ are the same or different, and each R １ a group or a monovalent group of the formula Z=-y-(Y')n, (In the formula, - y represents a polyvalent C1-C18 alkylene or heteroalkylene group, said alkylene and heteroalkylene groups may be linear or branched, optionally interrupted by one or more cycloalkylene groups and optionally extended by a C1-C4 oxyalkylene or polyoxyalkylene divalent group, said alkylene, heteroalkylene, oxyalkylene and polyoxyalkylene groups being optionally substituted by one or more hydroxy groups, -Y' represents a monovalent alkenylcarbonyloxy group; - n is equal to 1, 2, or 3) a=1 to 499, b=1 to 250, c=0, d=0, at least one symbol R ２ Or R ３ represents a monovalent group of formula Z. Organopolysiloxane A, which corresponds to b. at least 25% by weight of an organopolysiloxane resin B containing Si—OH groups; c. Optionally, at least one radical photoinitiator C A radiation-curable silicone composition X comprising:

2. 10. The silicone composition of claim 1, which is curable by electron or photon irradiation.

3. 3. The silicone composition X according to claim 1, wherein the organopolysiloxane A has a molar content of (meth)acrylate functional groups of 30 mmol / 100 g of organopolysiloxane A or more.

4. The organopolysiloxane A is a1. at least one organopolysiloxane A1 containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of 30 mmol / 100 g of organopolysiloxane A1 or more; and a2. At least one organopolysiloxane A2 containing at least one (meth)acrylate group and having a molar content of (meth)acrylate functional groups of less than 30 mmol / 100 g of organopolysiloxane A2 The silicone composition X according to any one of claims 1 to 3, comprising:

5. 5. The silicone composition X according to claim 4, which comprises 0.1 to 10% by weight of organopolysiloxane A2.

6. 6. The silicone composition X according to claim 1, which comprises 25 to 60% by weight of resin B.

7. Silicone composition X according to any one of claims 1 to 6, in which resin B has an OH functional group content comprised between 0.2 and 5% by weight.

8. 8. Silicone composition X according to any one of claims 1 to 7, wherein resin B is an MDT resin or an MQ resin.

9. 9. The silicone composition X according to claim 1, further comprising an organic compound D comprising at least one (meth)acrylate functional group.

10. 10. Use of a silicone composition X according to any one of claims 1 to 9 for the preparation of a silicone elastomer which can be used as a release coating on a substrate.

11. 1. A method for preparing a coating on a substrate, comprising: - applying a silicone composition X according to any one of claims 1 to 9 to a substrate, and - a method comprising the step of curing said composition by electron or photon irradiation.

12. 12. The method of claim 11, wherein the substrate is a flexible substrate made of textile, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyethylene terephthalate, polyurethane, or non-woven glass fiber.

13. A coated substrate obtainable by the method according to claim 11 or 12.

14. 1. A premix for a silicone composition comprising: a. 20-40 wt. % of at least one organopolysiloxane A containing at least one (meth)acrylate group; b. 30 to 50% by weight of an organopolysiloxane resin B containing Si—OH groups, and c. 10 to 30% by weight of an organic compound D containing a (meth)acrylate functional group Including, premix.

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