Low compression permanent set silicone rubber composition

Abstract

The present invention relates to curable silicone rubber compositions that can be cured to silicone rubber compositions having low compression set and uses of such curable silicone rubber compositions.

Description

Technical Field

[0001] The present invention relates to a curable silicone rubber composition that can be cured into a silicone rubber composition having low compression set, and to the use of such a curable silicone rubber composition for the manufacture of automotive parts such as connector seals, electrical and electronic parts, packaging parts, construction parts such as seals, and household parts.

Background Art

[0002] Modern automobiles and trucks rely on electrical and electronic systems to function according to technical regulations, enable the latest technologies, and meet consumer demands. Electrical failures can lead to malfunctions of automotive devices such as radios, lights, and ventilation in the best case, and in the worst case, vehicle failures or violations of legal standards such as emissions. Some automobile manufacturers may have vehicle models and equipment with wires exceeding 3 km inside the vehicle, and so-called wire harnesses will connect more than 200 electronic and electrical (E&E) devices using electrical connectors. Many of these electrical connectors need to be protected from moisture and environmental attacks that can cause poor connections. In most of these connectors, self-lubricating silicone elastomers are used to seal the connector housings together and to seal the cable / contact assembly against the housing.

[0003] The lubrication of these self-lubricating silicone elastomers is achieved by phenyl silicone fluid that oozes out from the cured seal over time. Lubrication facilitates the assembly of cables and connectors. The general hardness of cable and interface (peripheral) seals ranges between 30 and 50 Shore A. Softer materials are often used for mat seals with multiple contact points. Harder materials are mainly used for peripheral seals, depending on the manufacturer and system design.

[0004] Due to the improvement of encapsulation, the improvement of engine efficiency, miniaturization, and the implementation of a turbocharger combined with the limited available space, some electrical connection points have to withstand the current high temperatures.

[0005] The current hermetic connector assemblies meet the T3 temperature class of relevant automotive specifications such as SAE US CAR in the temperature range from -40°C to 125°C. To meet the criteria of the high-temperature classes T4 (-40°C to 150°C) and T5 (-40°C to 175°C), a new technical approach for silicone elastomer sealing materials is required to provide the necessary thermal stability and low long-term compression set over a 1008-hour test period.

[0006] Compression set according to ISO 815 represents the permanent hardening / deformation after compression and storage under specific time and temperature conditions. Zero compression set is desirable so that the seal will fully recover after the load or assembly is removed.

[0007] In practice, compression set indirectly represents the case where the sealing force is still available (when there is no permanent set of the material). A very low long-term (e.g., 1000 hours) compression set is desired for long-term reliable sealing performance.

[0008] WO2009 / 003819 relates to a high-temperature vulcanized silicone rubber having improved tracking resistance and erosion resistance, containing from 2 to 40 parts by weight of melamine cyanurate per 100 parts by weight of a silicone base as a filler. The introduction of melamine cyanurate is mentioned to lead to an improvement in tracking resistance and flame retardancy without impairing the mechanical properties. WO2009 / 003819 does not mention anything about a curable silicone rubber composition providing a low compression set. SUMMARY OF THE INVENTION

[0009] The inventors have searched for a curable silicone rubber composition that particularly meets the need for low compression set over a long period at high temperatures. As a result, the inventors have found a specific curable silicone rubber composition that meets the above needs, particularly with respect to the organohydrogensiloxane component, which satisfies specific requirements.

[0010] According to the present invention, there is provided a curable silicone rubber composition that can be cured by vulcanizing a cured composition having at least one compression set value selected from the group of compression set values of 30% or less, preferably 25% or less, more preferably 20% or less after a 144-hour test at 175°C, and 50% or less, preferably 40% or less after a 1000-hour test at 175°C. A) 100 parts by weight of at least one polyorganosiloxane having at least one alkenyl group R 1 and B) 0.01 to 100 parts by weight of at least one organohydrogensiloxane having at least two SiH groups, wherein component B) is selected from at least one organohydrogensiloxane having at least two SiH groups, which is selected from one or more polyorganohydrogensiloxanes of the general formula (2). [M a D b T c Q d Z e m (2) where M = R3SiO 1 / 2 and / or M * D = R2SiO 2 / 2 and / or D * T = RSiO 3 / 2 and / or T * Q = SiO 4 / 2 and where M * = HR2SiO 1 / 2 D * = HRSiO 2 / 2 T * ​=HSiO 3 / 2 and Z is a divalent optionally substituted hydrocarbyl bridging group having up to 14 carbon atoms between two siloxy groups, said siloxy groups being as defined above, R is independently selected from saturated or aromatic organic groups, a = 0.01 - 10, preferably = 2 - 5, most preferably = 2 b = 0 - 1000, preferably = 10 - 500 c = 0 - 50, preferably = 0 d = 0 - 5, preferably = 0 e = 0 - 3, preferably = 0 m = 1 - 1000, preferably = 1 - 500, most preferably = 1 provided that M * , D * and T * are present with the proviso that at least two groups selected from are present, C) at least one transition metal catalyst, D) 0.01 to 100 parts by weight of at least one reinforcing filler having a BET surface area of at least 50 m 2 / g, and G) optionally up to 100 parts by weight of one or more auxiliary additives, comprising, wherein component A) comprises at least one component A1) and at least one component A2) as defined below: A1) at least one polyorganosiloxane of formula (Ia), [Chemical formula] where each R is independently selected from saturated or aromatic organic groups, each R 1 is independently selected from alkenyl groups, and X is ≧0, A2) at least one polyorganosiloxane of formula (Ib) [Chemical formula] where x, R and R 1is as defined above; R 2 is R or R 1 selected from, and y is ≧1, and here preferably, the alkenyl group R in component A2 1 to the alkenyl group R in component A1 1 The molar ratio is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5, and here the composition satisfies one, preferably two or more of the following requirements a) to c), a) The molar ratio of all SiH groups in the composition to all groups SiR 1 (where R 1 is as defined above) (or briefly, the molar ratio of SiH groups to groups SiR 1 ) is ≦3, preferably ≦2, more preferably between 1.0 and 1.8; and b) The important impact factor KpSiH (mmol / g) defined below is 2.5 to 17.5 mmol / g, preferably 2.5 to 15 mmol / g; [Number] where - 「parts B i 」 is the weight percentage of the i-th component B) based on the total weight of the composition, - 「SiH ofB i 」 is the SiH content (mmol / gram) of the i-th component B), - 「SiH(B i )」 is the number of SiH groups of the i-th component B) per molecule, - 「SiH / SiR 1 」 is as defined in item a) above, [Number] where D is R2SiO of component B 2 / 2 , M is R3SiO of component B 1 / 2 , D * is HRSiO of component B) 2 / 2 and M * = HR2SiO of component B) 1 / 2 where R is as defined above, and P of each i-th component B) having the necessary units i (D * D * ) is preferably from 0 to 1, more preferably from 0 to 0.9, and most preferably from 0 to 0.85; c) The molar ratio of the alkenyl group R in component A2) to the alkenyl group R in component A1) is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5. 1 of the alkenyl group R in component A1) 1 is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5.

[0011] Preferred embodiments of the present invention are described below.

[0012] Component A) A polyorganosiloxane having at least one alkenyl group R 1 In the present invention, component A) comprises at least one component A1) and at least one component A2) defined as follows: A1) At least one polyorganosiloxane of formula (Ia), A1) At least one polyorganosiloxane of formula (Ia), [Chemical formula] where each R is independently selected from saturated or aromatic organic groups, each R 1 is independently selected from alkenyl groups, and x is 0 or more; A2) At least one polyorganosiloxane of formula (Ib), [Chemical formula] where x, R and R 1 are as defined above; R 2 is selected from R or R 1 and y is ≧ 1.

[0013] In a preferred embodiment of the present invention, in the curable silicone rubber composition, the molar ratio of the alkenyl group R in component A2) to the alkenyl group in component A1) is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5. 1

[0014] Component A1) The composition of the present invention contains at least one polyorganosiloxane A1) of formula (Ia): [Chemical formula] Where each R is independently selected from saturated or aromatic organic groups, and R 1 is selected from alkenyl groups, and x is 0 or more, preferably x is 10 or more, more preferably x is 100 or more, and preferably x is less than 2000, more preferably less than 1500, even more preferably less than 1000.

[0015] Preferably, the viscosity of component A1) at 25 °C is less than 100,000 mPa·s, preferably the viscosity exceeds 5000 mPa·s (measured at a shear rate of D = 10 s at 25 °C -1 ).

[0016] The viscosity of such a polymer is preferably in the range of 10 to 100,000 mPa·s, more preferably 40 to 70,000 mPa·s (measured at a shear rate of D = 10 s at 25 °C -1 ).

[0017] The viscosity of component A1) refers to the viscosity of a single component A1) or a mixture of components (A). In the case of the latter mixture, it includes the presence of individual component A1) having a viscosity exceeding 100,000 mPa·s at 25 °C.

[0018] Group R is preferably selected from optionally substituted alkyl groups having up to 30 carbon atoms and optionally substituted aryl groups having up to 30 carbon atoms. More preferably, group R is selected from n-, iso-, or tertiary alkyl, alkoxyalkyl, C5-C 30 -cyclic alkyl, or C6-C 30 -aryl, alkylaryl, and these groups can optionally contain one or more -O-, -NH-, -S-, and

Chemical formula

[0019] Examples of suitable monovalent hydrocarbon radicals include alkyl radicals, preferably, for example, CH3-, CH3CH2-, (CH3)2CH-, C8H 17 - and C 10 H 21 -, and alicyclic radicals, such as cyclohexylethyl, aryl radicals, such as phenyl, tolyl, xylyl, aralkyl radicals, such as benzyl and 2-phenylethyl. Preferred monovalent halo hydrocarbon radicals have the formula C n F 2n+1 CH2CH2-, where n has a value from 1 to 10, for example, CF3CH2CH2-, C4F9CH2CH2-, C6F 13 CH2CH2-, C2F5-O(CF2-CF2-O) 1-10 CF2-, F[CF(CF3)-CF2-O] 1-5 -(CF2) 0-2 -, C3F7-OCF(CF3)-, and C3F7-OCF(CF3)-CF2-OCF(CF3)-.

[0020] The most preferred groups for R include methyl, phenyl, and 3,3,3-trifluoropropyl, and particularly preferred R is methyl.

[0021] R1 is preferably selected from aliphatic unsaturated groups containing a C═C-group (═ alkenyl group), for example, n-, iso-, tertiary, or cyclic alkenyl groups having up to 30 carbon atoms, C6-C 30 -cycloalkenyl, C8-C 30 -alkenylaryl, cycloalkenylalkyl, for example, vinyl, allyl, methallyl, 3-butenyl, 5-hexenyl, 7-octenyl, ethylidene-norbornenyl, styryl, vinylphenylethyl, norbornenylethyl, limonenyl, optionally containing one or more -O-atoms or F-atoms, and is selected from these.

[0022] R 1 The preferred groups are vinyl, 5-hexenyl, cyclohexenyl, limonyl, styryl, vinylphenylethyl. The most preferred group R 1 is vinyl.

[0023] The groups R and / or R 1 may be equal or different.

[0024] x is the average value calculated from the number average molecular weight M n of the polydiorganosiloxane of formula (Ia), which is determined by gel permeation chromatography using a polystyrene standard.

[0025] x is preferably 10 - 2000, more preferably 100 - 1000.

[0026] The number average molecular weight M n (determined by gel permeation chromatography using a polystyrene standard) is preferably in the range of up to 200000 g / mol, more preferably in the range of up to 100000 g / mol.

[0027] Preferred structures of the polydiorganosiloxane A1) include the following: ViMe2SiO(Me2SiO) 10-2000 SiMe2Vi (1a), ViPhMeSiO(Me2SiO) 10-2000 SiMePhVi (1b), where Vi is a vinyl group, Me is a methyl group, and Ph is a phenyl group. The polydiorganosiloxane of formula (1a) is particularly preferred.

[0028] In a preferred embodiment of the present invention, a mixture of at least two polydiorganosiloxanes A1) having different chain lengths is used. Preferably, a mixture of the following two polydiorganosiloxanes A1-1) and A1-2) is used: A1-1): R 1 R2SiO(R2SiO) x1 SiR2R 1 where x1 is from 10 to 700, and R and R 1 are as defined above, preferably R is methyl, and R 1 is vinyl, A1-2): R 1 R2SiO(R2SiO) x2 SiR2R 1 where x2 is >700, preferably >800, and R and R 1 are as defined above, preferably R is methyl, and R 1 is vinyl.

[0029] The weight ratio of A1-1) to A1-2) is preferably from 99:1 to 1:99, preferably from 49:51 to 10:90.

[0030] These polymers can be prepared by any of the conventional methods for preparing triorganosiloxane-terminated polydiorganosiloxanes. For example, appropriate hydrolyzable silanes in appropriate ratios, such as vinyldimethylchlorosilane, trimethylchlorosilane, tetrachlorosilane, methyltrichlorosilane and dimethyldichlorosilane, or their corresponding alkoxysilanes, can be co-hydrolyzed and condensed. Other reaction routes can alternately perform equilibration reactions of 1,3-divinyltetraorganodisiloxanes, such as symmetric divinyldimethyldiphenylsiloxane or divinyltetramethylsiloxane, which provide the end groups of the polydiorganosiloxane, which can be equilibrated with an appropriate polydiorganosiloxane, such as octamethylcyclotetrasiloxane, in the presence of an acidic or basic catalyst.

[0031] Preferably, the alkenyl content of component A1) ranges from 0.001 to 20 mol%, in particular from 0.01 to 10 mol%, based on all the organic groups bonded to the silicon atom.

[0032] The alkenyl content of component (A) 1 can be determined here by 1H NMR - see A.L. Smith (ed.): The Analytical Chemistry of Silicones, J. Wiley & Sons 1991 Vol. 112 pp. 356 and the following items, Chemical Analysis, edited by J.D. Winefordner.

[0033] Component A2) The composition of the present invention comprises at least one polyorganosiloxane A2) of formula (Ib):

Chemical formula

[0034] The radicals R and / or R 1 The siloxane units having may be equal or different for each silicon atom. In a preferred embodiment, the structure is R 1 p R 3-p SiO[R2SiO] x [R 1 RSiO] y SiR 1 p R 3-p (1c) wherein R and R 1 are as defined above, p = 0 - 3, preferably 1, x = 10 - 2000, preferably 100 - 1000, y = 1 - 500, preferably 1 - 200, more preferably 1 - 100, even more preferably 1 - 50.

[0035] The purpose of component A2), a so-called alkenyl-rich, suitably vinyl-rich polymer, is to modify the mechanical properties and the crosslink density.

[0036] A preferred polydiorganosiloxane A2) is represented by the following formula, Me3SiO(Me2SiO) x (MeR 1 SiO) y SiMe3(1d), R 1 Me2SiO(Me2SiO) x (MeR 1 SiO) y SiMe2R 1 (1e), where x => 0 - 2000, preferably from 10 to 800, more preferably from 50 to 700, y => 0 - 500, preferably from 5 to 200, more preferably from 7 to 100, x + y => 10, preferably > 15, more preferably > 50, more preferably > 57, more preferably > 70, more preferably > 75, R 1 i.e., R is as defined above.

[0037] The more preferred polydiorganosiloxane A2) is represented by formula (1e).

[0038] In a preferred embodiment of the present invention, a mixture of at least two polydiorganosiloxanes A2) having different chain lengths is used. Preferably, a mixture of the following two polydiorganosiloxanes A2-1) and A2-2) is used: A2-1): R 1 Me2SiO(Me2SiO) x1 (MeR 1 SiO) y1 SiMe2R 1 (1f), x1 => 100 - 2000, preferably 200 to 800, more preferably 300 to 700, y1 => 10 - 500, preferably 15 to 200, more preferably 30 to 100, x1 + y1 => 110, preferably > 215, more preferably > 300, more preferably > 330, more preferably > 500, R 1 i.e., R is as defined above, A2-2): R 1 Me2SiO(Me2SiO) x2 (MeR 1 SiO) y2 SiMe2R 1 (1f), x2 => 10 - 100, preferably 20 to 100, more preferably 30 to 90, y2 => 1 - 100, preferably 5 to 70, more preferably 7 to < 30, x2 + y2 => 11, preferably > 30, more preferably > 50, R 1 i.e., R is as defined above.

[0039] The weight ratio of A2-1) to A2-2) is preferably from 99:1 to 1:99, preferably from 51:49 to 90:10.

[0040] R and R 1 Regarding the preferred embodiments, the definition of the above polyorganosiloxane A1) is referred to. R 1 = preferably vinyl, hexenyl, cyclohexenyl, limonyl, styryl, vinylphenylethyl. The most preferred R 1 is vinyl.

[0041] The preferred groups of R are methyl, phenyl, 3,3,3-trifluoropropyl, and the most preferred is methyl.

[0042] The preferred value of y (or y1 or y2) is less than 0.5*x (or x1 or x2), preferably from 0.0001*x (or x1 or x2) to 0.25*x (or x1 or x2), more preferably from 0.0015*x (or x1 or x2) to 0.2*x (or x1 or x2).

[0043] A more preferred structure of the polyorganosiloxane A2) is Vi p Me 3-p SiO(Me2SiO) 10-2000 (MeViSiO) 1-1000 SiMe 3-p Vi p (1f), Me3SiO(Me2SiO) 10-2000 (MeViSiO) 1-1000 SiMe3(1g), PhMeViSiO(Me2SiO) 10-2000 (MeViSiO) 1-1000 SiPhMeVi (1h), where Me = methyl, Vi = vinyl, Ph = phenyl, p = from 0 to 3, preferably p = 1.

[0044] The number average molecular weight M nis preferably in the range up to 100,000 g / mol, more preferably in the range up to 50,000 g / mol, and this is preferably determined using GPC with polystyrene standards.

[0045] In a preferred embodiment, the weight ratio of the polydiorganosiloxane A1) to the polydiorganosiloxane A2) is from 100:1 to 1:1, preferably from 20:1 to 2:1.

[0046] In the present invention, it is possible that component A) contains only at least one component A1) or only at least one component A2), that is, components A1) and A2) are not used together and can be used alone.

[0047] Component B): an organohydrogensiloxane having at least two SiH groups The curable silicone rubber composition contains component B), that is, at least one organohydrogensiloxane having at least two SiH groups, where component B) is selected from one or more polyorganohydrogensiloxanes of the general formula (2): [M a D b T c Q d Z e m (2) where M = R3SiO 1 / 2 , and / or M * D = R2SiO 2 / 2 , and / or D * T = RSiO 3 / 2 , and / or T * Q = SiO 4 / 2 , where M * = HR2SiO 1 / 2 , D * = HRSiO 2 / 2 , T * = HSiO 3 / 2 , ​Z is a divalent optionally substituted hydrocarbyl bridging group having up to 14 carbon atoms between two siloxy groups, these siloxy groups being as defined above, and R is as defined above, a = 0.01 - 10, preferably = 2 - 5, most preferably = 2 b = 0 - 1000, preferably = 10 - 500 c = 0 - 50, preferably = 0 d = 0 - 5, preferably = 0 e = 0 - 3, preferably = 0 m = 1 - 1000, preferably = 1 - 500, most preferably = 1, provided that * M * D * T * there are at least two groups selected from the group consisting of.

[0048] Preferably, component B) is selected from polysiloxanes having only methyl or phenyl groups as organic residues, even more preferably only methyl groups.

[0049] Preferably, the organohydrogensiloxane B) has at least 10, preferably at least 15, more preferably at least 20, even more preferably at least 25, and most preferably at least 30 silicon atoms.

[0050] The siloxy units can be distributed block by block or randomly within the polymer chain.

[0051] The above-mentioned indices will represent the average degree of polymerization P n based on the number average molecular weight M n of.

[0052] The range of M-, D-, T-, Q-units present in the molecule can cover almost all values representing fluids, flowable polymers, liquids and solid resins. It is preferred to use linear, cyclic or branched siloxanes of liquids. Optionally, these siloxanes can contain further trace amounts of C1-C6-alkoxy or Si-hydroxy groups remaining from the synthesis.

[0053] A preferred structure of component B) in the composition of the present invention is the siloxane of formulas (2a) to (2e). H a1 (R) 3-a1 Si[RHSiO] p [R2SiO] q [RR 1 SiO] z Si(R) 3-a1 H a1 (2a) More specifically, HR2SiO(R2SiO) q (RR 1 SiO) z (RHSiO) p SiR2H (2b) HMe2SiO(Me2SiO) q (RR 1 SiO) z (MeHSiO) p SiMe2H (2c) Me3SiO(MeHSiO) p SiMe3(2d) Me3SiO(Me2SiO) q (RR 1 SiO) z (MeHSiO) p SiMe3(2e) Here R and R 1 are as defined above, R is preferably methyl and / or phenyl, R 1 is preferably vinyl, the subscript "a1" is 0 or 1, p = 0 - 1000, preferably = 0 - 500, q = 0 - 650, preferably = 0 - 100, z = 0 - 65, preferably = 0, 2 ≤ p + q + z < 1000, preferably 10 ≤ p + q + z < 650.

[0054] Most preferably, HR2SiO(R2SiO) q (RR 1 SiO) z (RHSiO) p SiR2H (2b) where p, q, z are as defined above, where z is preferably 0, p is preferably 0, and q is preferably from 5 to 50, more preferably from 10 to 30.

[0055] In the above formulas (2a) to (2e), the molar ratio of all Si atoms to SiH groups is preferably greater than 0.01 and preferably up to 0.7, and the total number of Si atoms is preferably at least 7, more preferably at least 15, and even more preferably at least 20.

[0056] Furthermore, the use of resinous polyorganohydrogensiloxanes of the following formulas is preferred: {[T][R 29 O 1 / 2 n} m (2f) {[Q][R 29 O 1 / 2 n [M] 0,01-10 [T] 0-50,好ましくは0 [D] 0-1000,好ましくは0} m (2g) where Q, T, M, D are as defined above, n = 0 to 3, preferably n = 0, m is as defined above, R 29 is hydrogen, C1-C 25 ​​-Alkyl, for example, methyl, ethyl, n-propyl, iso-propyl, n-, iso-, and tert.-butyl, alkanoyl, for example, acyl, aryl, -N=CHR, for example, butanone oxime, alkenyl, for example, propenyl, and where M * , D * , and T * are present with the condition that there are at least two groups selected from. The most preferred resinous polyorganohydrogensiloxanes are those of the formula consisting of Q and M * units, for example, {[Q][M * 0,01-10,好ましくは1-10} m (2h) where Q, M * , and m are as defined above, and m is preferably from 1 to 20.

[0057] One preferred embodiment of compound (2g) is provided, by way of example, by a polymeric compound from monomers that can be described by the formula [(Me2HSiO 0.5 ) k SiO 4 / 2 1-1000 where the subscript k is from 0.3 to 4. Such liquid or resinous molecules can contain appreciable concentrations of SiOH- and / or (C1-C6)-alkoxy-Si groups up to 10 mol% with respect to silicon atoms.

[0058] Particularly preferred resinous polyorganohydrogensiloxanes B) are, for example, M * 2D 10-30 , Q(M * )4, M2D 10-30 D * 10-30 , and [M * 1-4 Q] 1-40 .

[0059] ​​The preferred viscosity of the resinous polyorganohydrogensiloxane B) is from 1 to 100 mPa·s at 25°C at a shear rate of D = 10 s -1 and 100 mPa·s.

[0060] Specific examples of suitable preferred compounds for component B) in the compositions of the present invention include Me3SiO-(MeHSiO) 2-50 -SiMe3, Me3SiO-(MeHSiO) 2-50 (Me2SiO) 1-100 SiMe3, (MeHSiO) 3-7 , HMe2SiO-(MeHSiO) 0-60 (Me2SiO) 1-250 SiMe2H HMe2SiO(Me2SiO) 0-30 (MePhSiO) 0-30 (MeHSiO) 2-50 SiMe2H, Me3SiO(Me2SiO) 0-30 (MePhSiO) 0-30 (MeHSiO) 2-50 SiMe3, Me3SiO(Me2SiO) 0-30 (Ph2SiO) 0-30 (MeHSiO) 2-50 SiMe3, are included, wherein in each formula, the molar ratio of all Si atoms of the SiH groups is preferably greater than 0.01, and the total number of Si atoms preferably has at least 7 atoms, more preferably at least 10, more preferably at least 15, and most preferably at least 20 atoms.

[0061] The SiH content of the polyorganohydrogensiloxane B) is preferably at least 0.1 mmol / g, more preferably at least 0.2 mmol / g, and preferably at most 17 mmol / g, more preferably at most 15 mmol / g, more preferably from 0.1 to 17 mmol / g, and most preferably from 0.2 to 13 mmol / g. When using more than one component B), these Si contents apply to each specific component B) used.

[0062] Most preferably, it is a compound of the formula HMe2SiO-(MeHSiO) 0-60 (Me2SiO) 1-250 SiMe2H, and even more preferably at least one resinous polyorganohydrogensiloxane B), preferably of the formula [M * 1-4 Q] 1-40 and is preferably in a mixture with HMe2SiO-(MeHSiO) 0-60 (Me2SiO) 1-250 SiMe2H / [M * 1-4 Q] 1-40 in a weight ratio ranging from 49:51 to 1:99.

[0063] Component B) can be used as a single component of one polyorganohydrogensiloxane or preferably as a mixture of at least two of them. Most preferably, it is a mixture of a linear polyorganohydrogensiloxane consisting of D and / or D * and M and / or M * units and a resinous polyorganohydrogensiloxane consisting of Q and M and / or M * units, preferably in a weight ratio of 49:51 to 1:99.

[0064] If it is necessary to increase the curing rate, in order to adjust the curing rate to a shorter time, HMe2SiO 0,5- It is preferred to use some organopolysiloxanes B) having units or homo-MeHSiO-polymers.

[0065] If it is necessary to further increase the curing rate, this can be achieved, for example, by increasing the molar ratio of SiH to Si-alkenyl or by increasing the amount of catalyst C).

[0066] Component B) preferably has a viscosity of 2 to 2000 mPa·s, preferably 1 to 1000 mPa·s, and even more preferably 2 to 100 mPa·s at 25 °C (preferably measured at a shear rate of D = 10 s -1 ).

[0067] Preferably, the crosslinking agent B) should have at least 2, more preferably at least 3, and in some cases also more than 15 and more than 20 SiH groups per molecule.

[0068] In a preferred embodiment of the present invention, the curable silicone rubber composition contains at least one resin-based organohydrogensiloxane containing at least one unit selected from T, T * and Q, preferably Q.

[0069] In a particularly preferred embodiment of the present invention, at least two different organohydrogensiloxanes B) are used in the curable silicone rubber composition. Further, in the curable silicone rubber composition according to the present invention, preferably, the organohydrogensiloxane B) has terminal SiH groups with B1)>2, preferably T, T * and Q, preferably Q, and is selected from the group of resin-based organohydrogensiloxanes containing at least one unit, and B2) having two or more SiH groups and being different from B1).

[0070] Transition metal catalyst C) The curable silicone rubber composition according to the present invention contains at least one transition metal catalyst C).

[0071] Component C) is preferably selected from the group of organometallic compounds, salts or metals having the ability to catalyze hydrosilylation, where the metal is as taught in US 3,159,601; US 3,159,662; US 3,419,593; US 3,715,334; US 3,775,452 and US 3,814,730, and the metal is selected from the group of Ni, Ir, Rh, Ru, Os, Pd and Pt compounds. Platinum compounds are most preferred.

[0072] Preferably, the transition metal catalyst C) is selected from hydrosilylation catalysts containing at least one metal selected from the group consisting of platinum, rhodium, palladium, ruthenium and iridium.

[0073] The catalyst component C) for the hydrosilylation reaction of the composition of the present invention is a compound that promotes the reaction of the silicon-bonded hydrogen atoms of component (B) with the silicon-bonded olefin hydrocarbon substituents of component (A). The metal or organometallic compound is generally based on platinum group metals. Without wishing to be bound by theory, it is believed that catalyst (C) includes sigma bonds and pi bond carbon ligands, ligands containing S, N, or P atoms, metal colloids or salts with complexes involving the aforementioned metals. The catalyst can be present on a support such as silica gel or powdered carbon that supports the metal, or a compound or complex of that metal. Preferably, the metal of component (C) is any platinum complex compound.

[0074] Typical platinum-containing catalyst components in the polyorganosiloxane composition of the present invention are any form of platinum(0), (II) or (IV) compounds capable of forming complexes. Preferred complexes are Pt-(0)-alkenyl complexes, such as alkenyl, cycloalkenyl, alkenylsiloxanes, such as vinylsiloxanes, for their easy dispersibility in the polyorganosiloxane composition.

[0075] A particularly useful form of the platinum complex is 1,3-divinyltetramethyldisiloxane (vinyl-M2 or Karstedt catalyst [Chemical formula] It is a Pt(0)-complex with an aliphatic unsaturated organosilicon compound such as Those disclosed in US 3,419,593 incorporated by reference, for example, are particularly preferred, such as cyclohexene-Pt, cyclooctadiene-Pt and tetravinyltetramethyl-tetracyclosiloxane (vinyl-D4)-Pt, for example, Ashby catalyst, empirical formula Pt[(C3H6SiO)4] x It is a Pt(0) complex in tetramethyltetravinylcyclotetrasiloxane of

[0076] The most preferred catalyst component (C) is a Pt complex with tetramethyl-tetravinylcyclotetrasiloxane containing about 1 to 3% by weight of Pt, preferably 2% by weight of Pt 0 complex, especially the Ashby catalyst.

[0077] Also preferably, it is a so-called Lamoreaux catalyst which is a platinum(II) complex compound obtained from chloroplatinic acid hexahydrate and octyl alcohol (for example, described in US 3,197,432 or US 3,220,972). Preferably, it is a Pt(0) or Pt(II) catalyst, and Ashby and Lamoreaux platinum catalysts are preferred.

[0078] The amount of the platinum-containing catalyst component used in the composition of the present invention is not narrowly limited as long as there is an amount sufficient to promote hydrosilylation between (A) and (B) at the desired temperature for the required time (B) in the presence of all other components of the composition of the present invention. The exact required amount of the catalyst component will depend on the particular catalyst, the amount of other inhibiting compounds, and the SiH to olefin ratio and cannot be readily predicted. However, in the case of platinum catalysts, for cost reasons, the above amount can be made as low as possible. Preferably, in order to ensure curing in the presence of other undefined trace amounts of inhibitors, platinum in excess of 1 part by weight per million parts by weight of the organosilicon components (A) and (B) is added. For the composition of the present invention, the amount of the platinum-containing catalyst component applied is preferably sufficient to provide from 1 to 200 ppm, preferably from 2 to 100 ppm, particularly preferably from 4 to 60 ppm of platinum per weight of the polyorganosiloxane component (A) plus (B). Preferably, said amount is at least 4 weight ppm of platinum per total of (A) and (B).

[0079] The hydrosilylation catalyst can also be selected from the group of catalysts that can be photoactivated. These photoactivable catalysts preferably contain at least one metal selected from the group consisting of Pt, Pd, Rh, Co, Ni, Ir or Ru. The catalyst that can be photoactivated preferably contains a platinum compound. The catalyst that can be photoactivable is preferably selected from organometallic compounds, i.e., contains a carbon-containing ligand or a salt thereof. In a preferred embodiment, the photoactive catalyst (C) has a metal-carbon bond containing a sigma bond and a pi bond. Preferably, the photoactivable catalyst (C) is an organometallic complex compound having at least one metal-carbon sigma bond, and even more preferably, a platinum complex compound having preferably one or more sigma bond alkyl and / or aryl groups, preferably an alkyl group. Sigma bond ligands include, in particular, sigma bond organic groups, preferably sigma bond C1-C6-alkyl, more preferably sigma bond methyl group, sigma bond aryl groups such as phenyl, Si and O-substituted sigma bond alkyl or aryl groups, for example, sigma bond silyl groups such as triorganosilylalkyl group, trialkylsilyl group. The most preferred photoactivable catalyst has a sigma bond ligand, preferably a sigma bond alkyl ligand η 5 -(optionally substituted)-cyclopentadienyl platinum complex compound.

[0080] Further catalysts that can be photoactivated include (η-diolefin)-(sigma-aryl)-platinum complexes (see, for example, US4,530,879).

[0081] The catalyst that can be photoactivated can be used by itself or can be supported on a carrier.

[0082] Examples of photoactivatable catalysts include η-diolefin-σ-aryl-platinum complexes, such as those described in US 4,530,879, EP 122008, EP 146307 (corresponding to US 4,510,094 and cited herein as a prior art document), or US 2003 / 0199603, and also platinum compounds whose reactivity can be controlled using, for example, azodicarboxylic acid esters or diketonates as described in US 4,640,939.

[0083] Furthermore, photoactivatable platinum compounds that can be used are those selected from the group having ligands selected from diketones, such as benzoylacetone or acetylenedicarboxylic acid esters, and platinum catalysts embedded in a photodegradable organic resin. Other Pt catalysts are described, for example, in US 3,715,334 or US 3,419,593, EP 1672031 A1, and Lewis, Colborn, Grade, Bryant, Sumpter, and Scott in Organometallics, 1995, 14, 2202-2213, all of which are hereby incorporated by reference into this specification.

[0084] The photoactivatable catalyst can also be formed in situ in the silicone composition to be molded by using a Pt(0)-olefin complex and adding an appropriate photoactivatable ligand thereto.

[0085] However, the photoactivatable catalysts that can be used here are not limited to the above examples.

[0086] The most preferred catalysts that can be photoactivated and used in the method of the present invention are (η 5 -cyclopentadienyl)-trimethyl-platinum, (η 5 -cyclopentadienyl)-triphenyl-platinum complex, especially (η 5 -methylcyclopentadienyl)-trimethyl-platinum.

[0087] The amount of the catalyst capable of being photoactivated is preferably from 1 to 500 ppm and preferably in a range lower than that defined for the above heat-activatable hydrosilylation catalyst.

[0088] The most preferred curable silicone rubber composition according to the present invention contains a hydrosilylation catalyst C) containing platinum.

[0089] Reinforcing filler D) The curable silicone rubber composition according to the present invention preferably contains at least one reinforcing filler D) selected from at least one, preferably surface-treated silica filler.

[0090] Preferably, the reinforcing filler D) is a silica filler selected from the group of fumed silica and precipitated silica having a BET of 50 to 500 m 2 / g measured according to DIN-ISO 9277 using nitrogen. Most preferably, the reinforcing filler D) is a silica filler selected from surface-treated fillers.

[0091] Preferably, the surface treatment of the silica filler is disilazane, silylamine, silanol, of the formula [R a R b R c Si(OSi(Me)2) t 2NH(R a is methyl, ethyl, or phenyl; R b is methyl or ethyl, R cis vinyl or allyl; and t is an integer from 2 to 12), bis(polyorganosiloxanyl)amine, trimethylsilanol, trimethylchlorosilane, trimethylethoxysilane, triorganosilyloxy acylate, for example, vinyldimethylacetoxysilane, triorganosilylamine, for example, trimethylsilylisopropylamine, trimethylsilylethylamine, dimethylphenylsilylpropylamine, and vinyldimethylsilylbutylamine, triorganosilylaminooxy compound, for example, diethylaminooxytriethylsilane and diethylaminooxydimethylphenylsilane, and further hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 1,3-diphenyltetramethyldisilazane, and can be carried out by reaction with a hydrophobic substance selected from the group consisting of

[0092] Other examples of organosilicon compounds are dimethyldichlorosilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, vinylmethyldimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, and / or dimethylpolysiloxane having from 2 to 12 siloxane units per molecule and containing a hydroxy group bonded to Si in each of the terminal units.

[0093] Most preferably, the reinforcing filler D) is at least one silazane, preferably an organosilazane, for example of the formula R'3Si-[NH-SiR'2] n -NH-SiR'3 where n is 0 or more), and R' is an organic group, preferably selected from methyl and / or vinyl, and is at least one silica filler surface-treated with the same. Most preferred are divinyltetramethyldisilazane and hexamethyldisilazane and mixtures thereof.

[0094] In certain preferred embodiments, the silica filler is subjected to an extended surface treatment with one or more organosilazanes, which can include a single-step treatment over a long period of time, such as at least 2 or 3 hours, or a multi-step surface treatment.

[0095] In certain preferred embodiments, the surface-treated silica filler is prepared by surface treatment of silica in a two-step process involving a subsequent reaction of the silica with at least 2 charges of silazane. Preferably, at least one silica filler is a surface-treated silica filler, which is obtained by the following steps: a) Providing a mixture comprising component A), B) and at least one silica filler D); b) Adding to the mixture at least one silazane having at least one alkenyl group and at least one silazane having no alkenyl group; c) Heating to at least 100 °C for at least 1 hour; d) Removal of volatiles, and e) Further adding, preferably, at least one silazane having no alkenyl group; f) Heating to at least 100 °C for at least 1 hour, and g) Removal of volatiles.

[0096] Preferred silica fillers are preferably those known as reinforcing silica, which also enables the production of elastomers having sufficient transparency to irradiation. Reinforcing silica, particularly those enhancing strength, are preferred. As an example, the BET surface area, preferably measured according to DIN-ISO 9277 using nitrogen, is from 50 to 400 m 2 / g, preferably from 80 to 350 m 2Silica which is / g, especially fumed or precipitated silica. Preferably, these fillers are surface-hydrophobized. The amount of the reinforcing filler D) is preferably 1 to 100 parts by weight, more preferably 5 to 90 parts by weight, even more preferably 10 to 80 parts by weight, even more preferably 15 to 70 parts by weight, based on 100 parts by weight of the total amount of components (A) and (B).

[0097] Fillers with a BET surface area exceeding 50 m 2 / g enable the production of silicone elastomers with improved properties. From the viewpoints of strength and transparency, fumed silica is preferred, and even more preferred silicas are, for example, Aerosil® 200, 300, HDK® N20 or T30, Cab-O-Sil® MS7 or HS5, which have a BET surface area exceeding 200 m 2 / g. As the BET surface area increases, the transparency of the silicone mixture in which these materials are present also increases. Examples of the trade names of materials known as precipitated silica or wet silica are Vulkasil® VN3 or FK 160 manufactured by Evonik (formerly Degussa), or Nipsil® LP and others manufactured by Nippon Silica K.K.

[0098] 50 m 2 / g or more, preferably having a BET surface area of at least 150 m 2 / g is preferably used. Such compositions can also be photoactivated as necessary for sufficient transparency.

[0099] Reinforcing filler D) may be subjected to appropriate conventional surface treatment with an appropriate surface treatment agent belonging to hydrophobic treatment with an appropriate hydrophobizing agent, and dispersion treatment with an appropriate dispersant, which affect the filler interaction with the silicone polymer, for example, affect the thickening effect. The surface treatment of the filler is preferably hydrophobization with silane or siloxane. As an example, silazanes such as hexamethyldisilazane and / or 1,3-divinyltetramethyldisilazane can be carried out in situ by adding water, and "in-situ" hydrophobization is preferred. Also, for the purpose of providing reaction sites for crosslinking reactions, other common filler treatment agents can be used with polyorganosiloxane diols having an unsaturated organic radical with a chain length of 2 to 50.

[0100] Examples of commercially available silicas pre-hydrophobized with various silanes are Aerosil® R972, R974, R976, or R812, or, for example, HDK 2000 or H30. Examples of trade names of materials known as hydrophobized precipitated silica or wet silica are, for example, Sipernat D10 or D15 manufactured by Evonik (formerly Degussa).

[0101] The rheological properties of the uncured silicone rubber mixture, i.e., the technical processing properties, can be affected by the type of filler, its amount, and the choice of the nature of hydrophobization.

[0102] Auxiliary additive G) The curable silicone rubber composition according to the present invention optionally contains one or more auxiliary additives G) up to 100 parts by weight. Auxiliary additive G) is different from any of the other components (A1), A2), B), C), D), E), and F)) defined herein, and is preferably selected from the group consisting of low compression set additives, surface treatment agents, lubricating oils, oil bleed agents, hydrosilylation inhibitors, and the like.

[0103] Auxiliary additive G) may particularly include the following: - Low compression permanent set additives, such as acetylene alcohols having the following formula: H-C≡C-R’’-OH, where R’’ is a divalent organic group, preferably a cyclic saturated or unsaturated hydrocarbyl group, such as cyclohexane-diyl, fluorene-diyl, such as 1-ethynyl-1-cyclohexanol (“ECH”), 9-ethynyl-fluorenol, etc., preferably ECH and 9-ethynyl-9-fluorenol, most preferably ECH (these compounds also act as hydrosilylation inhibitors), - Curing retardants or flame retardants, such as triazole compounds, such as 1,2,3-triazole, 1,2,4,-triazole, benzotriazole, 1-methyl-1,2,3-triazole, 1-phenyl-1,2,3-triazole, 4-methyl-2-phenyl-1,2,3-triazole, 1-benzyl-1,2,3-triazole, 4-hydroxy-1,2,3-triazole, 1-amino-1,2,3-triazole, 1-benzamide-4-methyl-1,2,3-triazole, 1-amino-4,5-diphenyl-1,2,3,-triazole, 1,2,3-triazole-4-aldehyde, 4-cyano-1,2,3-triazole, 1-methyl-1,2,4-triazole, 1,3-diphenyl-1,2,4-triazole, 5-amino-3-methyl-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 1-phenyl-1,2,4-triazole-5-one, 1-phenylurazole, 1-methylbenzotriazole, 5,6-dimethylbenzotriazole, 2-phenylbenzotriazole, 1-hydroxybenzotriazole, and methyl 1-benzotriazole carboxylate, those selected from the group consisting of metal salts, carbon black, phthalocyanine compounds or metal derivatives of the above compounds, where the metal is selected from the group consisting of copper, nickel, cobalt, iron, chromium, zinc, platinum, palladium, vanadium, - Surface treatment agents, - Lubricating oils, - Oil bleed agents, - Hydrosilylation inhibitors, - Colorants or pigments, such as inorganic pigments, and organic dyes, - Then, an accelerator, - A stabilizer such as a heat stabilizer, - Fillers such as reinforcing fillers and non-reinforcing fillers, for example, quartz powder, diatomaceous earth, calcium carbonate, - A dispersant, - A fluidity improver, - A plasticizer, - A slip agent, - A strengthening agent, - A conductive stability improver such as carbon black and graphite, and - A foam-forming additive, for example, alcohol, - An antioxidant, - A thixotropic agent, - A foam stabilizer, - An ultraviolet stabilizer, and - Water that can be used in the preparation of the curable silicone rubber composition.

[0104] In a preferred embodiment of the present invention, the curable silicone rubber composition does not contain quartz.

[0105] In a preferred embodiment of the present invention, the curable silicone rubber composition contains at least one hydrosilylation inhibitor, preferably 1-ethynyl-1-cyclohexanol ("ECH").

[0106] In a preferred embodiment of the present invention, the curable silicone rubber composition contains at least one colorant or pigment. Such colorants or pigments are not colorless, for example, like the preferred colorless metal oxides contained in component F), and may include inorganic pigments and organic dyes. In this regard, the curable silicone rubber composition according to the present invention can be provided in particular as a colorless curable silicone rubber composition, that is, one that does not contain a colorant or pigment (of course, not including the colorless metal oxide F)). From such a colorless curable silicone rubber composition according to the present invention, a colored curable silicone rubber composition can be easily obtained by mixing the colorless curable silicone rubber composition according to the present invention with at least one colorant or pigment or the colored metal oxide F) defined above, such as iron oxide red, etc. That is, the colorless curable silicone rubber composition of the present invention can serve as a basic composition for obtaining various types of colored curable silicone rubber compositions according to the present invention.

[0107] Melamine cyanurate E) The curable silicone rubber composition according to the present invention optionally contains melamine cyanurate E). Melamine cyanurate, also known as a melamine cyanuric acid adduct or a melamine cyanuric acid complex, is a crystalline complex formed from a 1:1 mixture of melamine and cyanuric acid.

Chemical formula

[0108] When the curable silicone rubber composition contains melamine cyanurate E), this amount is preferably less than 5 parts by weight, more preferably less than 2 parts by weight, based on 100 parts by weight of the total amount of components A) and B).

[0109] Melamine cyanurate is a well-known flame retardant in the plastics industry and is widely used in polyamide or polyvinyl chloride compositions. The present invention was to transfer the use of materials from a fast incineration oxidation process to a slow thermal aging oxidation process under atmospheric conditions. The result was clearly a success in binding O2 radicals within the melamine cyanurate structure, avoiding an attack on the silicone polymer backbone, thereby surprisingly reducing the compression set of the cured silicone rubber composition of the present invention.

[0110] Component F): At least one metal component The curable silicone rubber composition according to the present invention optionally contains at least one metal compound F), which is preferably selected from metal salts such as colored or colorless metal oxides, excluding silica.

[0111] In a preferred embodiment of the present invention, at least one metal compound F) is a colorless metal oxide selected from the group consisting of metal salts, in particular aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide and zinc oxide, and mixtures thereof. Oxides of transition metal compounds and mixtures thereof, such as iron oxide pigments (e.g., yellow iron oxide, red iron oxide, black iron oxide and mixtures thereof), mixed-phase metal oxide pigments, such as CoAl2O4 and Co(Al,Cr)2O4, synthetic and natural ultramarine, and chromium oxide, and colored metal oxides selected from the group consisting of mixtures of colorless metal oxides and colored metal oxides.

[0112] The preferred colorless metal oxides within the definition of component F) of the present invention are intended to mean that the oxides have no staining or coloring effect. Within the scope of the present invention, white metal oxides such as TiO2 are also colorless metal oxides. Usually, colorless metal oxides include white, opaque, translucent, or transparent metal oxides, for example, aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide, and zinc oxide, and mixtures thereof. Preferably, the colorless metal oxide F) is selected from the group consisting of titanium oxide, magnesium oxide, and mixtures thereof.

[0113] The colored metal oxides are preferably oxides of transition metal compounds and mixtures thereof, for example, iron oxide pigments (for example, yellow iron oxide, red iron oxide, black iron oxide, and mixtures thereof), mixed-phase metal oxide pigments, for example, CoAl2O4 and Co(Al,Cr)2O4, synthetic and natural ultramarine, and chromium oxide. In a preferred embodiment, the curable silicone rubber composition according to the present invention comprises a mixture of a colorless metal oxide and a colored metal oxide, preferably at least one of aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide, and zinc oxide, and a mixture of at least one iron oxide pigment.

[0114] The curable silicone rubber composition contains at least one metal compound, preferably at least one colorless metal oxide, in an amount of 0.01 to 10, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total amount of components A) and B). In a preferred embodiment, the amount of at least one metal compound is less than 2, preferably less than 1.9, preferably less than 1.8, preferably less than 1.7, preferably less than 1.6, preferably less than 1.5% by weight, based on the total composition of the curable silicone rubber composition or its cured composition.

[0115] The preferably used TiO2 is a finely divided metal oxide having a large specific surface area. This enables the material to be active towards catalytic processes and makes it useful as a heat stabilizer for elastomers. In addition, the whitish-looking additive can be colored above other colors such as the above-mentioned colored metal oxides or the colorants or pigments described for component G) above.

[0116] In a preferred embodiment, the curable silicone rubber composition according to the invention does not contain calcium hydroxide, and preferably the curable silicone rubber composition according to the invention does not contain alkali and alkaline earth metal hydroxides.

[0117] In a preferred embodiment, the curable silicone rubber composition of the present invention preferably satisfies one or more, preferably two or more, of the following requirements a) to c) in order to further improve the compression set: a) The molar ratio of all SiH groups in the composition to all groups SiR 1 (or, for short, the molar ratio of SiH groups to groups SiR 1 ) is ≦ 3, preferably ≦ 2, more preferably between 1.0 and 1.8; and b) The important impact factor KpSiH (mmol / g) defined below is between 2.5 and 17.5 mmol / g, preferably between 2.5 and 15 mmol / g;

Number

[0118] The inventors have found that particularly low compression set is achieved when the parameter KpSiH is in the preferred range of 2.5 to 17.5, preferably 2.5 to 15, more preferably 2.5 to 13, and even more preferably 3.5 to 12. It should be noted that when the composition contains only an organohydrogensiloxane having only terminal SiH groups, i.e., when the number of SiH groups in component B) per molecule is 2, KpSiH becomes zero, i.e., this embodiment is not very preferable because the mechanical properties of the cured composition may be inferior.

[0119] For higher KpSiH such as 17.5 or more, the mechanical properties of the silicone rubber will deteriorate. When the KpSiH value is less than 2.5, the mechanical properties of the silicone rubber will similarly deteriorate.

[0120] In the most preferred embodiment, the curable silicone rubber composition of the present invention preferably satisfies one, preferably two or more, or all of the following requirements a) to f) in order to further improve the compression set: a) The molar ratio of all SiH groups in the composition to all groups SiR 1 (or, for short, the molar ratio of SiH groups to groups SiR 1 ) is ≦ 3, preferably ≦ 2, more preferably between 1.0 and 1.8; and b) The important impact factor KpSiH (mmol / g) defined above is from 2.5 to 17.5 mmol / g, preferably from 2.5 to 15 mmol / g; c) The molar ratio of the alkenyl group R 1 in component A2) to the alkenyl group in component A1) is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5; d) The silica filler is subjected to a long-term surface treatment with one or more organosilazanes, which may include a long-term single-step treatment of at least 2 hours or 3 hours, etc., or a multi-step surface treatment, in particular a two-step process including a subsequent reaction of the silica with at least 2 charges of the silazane as described above, e) The curable silicone rubber composition contains one or more triazole compounds, and f) The curable silicone rubber composition contains at least one resin-based organohydrogensiloxane containing at least one unit selected from T, T * and Q, preferably Q.

[0121] The present invention further relates to a cured silicone rubber composition obtained by curing the curable silicone rubber composition according to the present invention.

[0122] The cured silicone rubber composition of the present invention exhibits a very low compression set, such as 30% or less, preferably 25% or less, more preferably 20% or less, after a 144-hour test at 175°C, or 50% or less, preferably 40% or less, after a 1000-hour test at 175°C.

[0123] In the present invention, the measurement of the compression set of the cured silicone rubber composition is carried out in accordance with INTERNATIONAL STANDARD ISO 815-1 First Edition 2008-02-01 with the following settings: - 4.5 Timing device: a) Example 1 - 5 Test specimens ·5.1 Outer dimensions: Type A: Cylindrical disk with a diameter of 29 mm ± 0.5 mm and a thickness of 12.5 mm ± 0.5 mm ·5.2 Preparation: The test specimens are prepared by molding each disk. ·5.3 At least three test specimens are tested. - 6 Test conditions: ·6.1 Test periods of 144 hours and 1000 hours ·6.2 Test temperature of 175°C ± 2°C - 7.3 Application of compression - The applied compression is (25 ± 2)% of the original thickness of the test specimen.

[0124] In a preferred embodiment of the present invention, the curable silicone rubber composition comprises the following: - A total of 100 parts by weight of components A1) and A2), - 0.01 to 100 parts by weight of component B), - Based on the weight of the transition metal and based on the total weight of components A) and B), 0.5 to 1000, preferably 1 to 100 ppm of component C), - Based on 100 parts by weight of the total amount of components A) and B), 0.01 to 100 parts by weight, preferably 10 to 100 parts by weight of component D) - Based on a total of 100 parts by weight of components A) and B), an amount of component E) of from 0 to 5 parts by weight, preferably less than 5 parts by weight, more preferably less than 2 parts by weight; based on a total of 100 parts by weight of components A) and B), preferably >0 and less than 5 parts by weight, more preferably less than 2 parts by weight, even more preferably from 0.01 to 2 parts by weight of component E), - Based on a total of 100 parts by weight of components A) and B), from 0 to 10 parts by weight of component F); based on a total of 100 parts by weight of components A) and B), preferably >0 to 10, more preferably from 0.01 to 10, even more preferably from 0.1 to 5 parts by weight of component F), and - Based on a total of 100 parts by weight of components A) and B), from 0 to 100 parts by weight of component G), wherein components A) to G) are each as defined above.

[0125] In a preferred embodiment, the curable silicone rubber composition of the present invention contains a total amount of D), E) and F) of less than 40 parts based on a total of 100 parts of components A) and B). Preferably, the curable silicone rubber composition of the present invention contains a total amount of D), E) and F) of more than 1 part, preferably more than 2 parts, based on a total of 100 parts of components A) and B).

[0126] In a preferred embodiment, the curable silicone rubber composition of the present invention contains D), E) and F).

[0127] The present invention further relates to a cured silicone rubber composition obtained by curing the curable silicone rubber composition according to the present invention.

[0128] The cured silicone rubber composition of the present invention exhibits a very low compression set of 10 percent or less after testing at 175°C for 22 hours, or 20 percent or less after testing at 175°C for 144 hours, or 40 percent or less after testing at 175°C for 1000 hours, etc.

[0129] Therefore, the curable silicone rubber composition of the present invention can be used, in particular, for the manufacture of automotive parts such as connector seals, electrical and electronic parts, packaging parts, construction parts such as seals, household parts, and gasket seals. The most preferred curable silicone rubber composition of the present invention is used, in particular, for the manufacture of shielded connector assemblies for automotive applications.

[0130] Preferred Embodiments of the Present Invention The preferred embodiments of the present invention are summarized below.

[0131] Embodiment 1. A curable silicone rubber composition that can be vulcanized and cured to a cured composition having a compression set value selected from the group of 30% or less, preferably 25% or less, more preferably 20% or less after a 144-hour test at 175°C, and 50% or less, preferably 40% or less after a 1000-hour test at 175°C, A) 100 parts by weight of at least one polyorganosiloxane having at least one alkenyl group R defined above 1 ; B) 0.01 to 100 parts by weight of at least one organohydrosiloxane having at least two SiH groups defined above C) At least one transition metal catalyst D) 0.01 to 100 parts by weight of at least one reinforcing filler having a BET surface area of at least 50 m 2 / g, and G) Optionally up to 100 parts by weight of one or more auxiliary additives, and wherein the composition satisfies one, preferably two or more, of the following requirements a) to c): a) The molar ratio of all SiH groups in the composition to all groups SiR 1 (R 1 is as defined above) (or, briefly, the molar ratio of SiH groups to groups SiR 1 ) is 3 or less, preferably 2 or less, more preferably between 1.0 and 1.8; b) The important impact factor KpSiH (mmol / g) defined below is from 2.5 to 17.5 mmol / g, preferably from 2.5 to 15 mmol / g;

Number

Number

[0132] 2. At least one reinforcing filler D) is selected from at least one, preferably surface-treated silica filler, and preferably at least one reinforcing filler D) is fumed silica, precipitated silica, and surface-treated fillers having a BET of 50 to 500 m 2 / g, a curable silicone rubber composition according to Embodiment 1, selected from the group of fillers.

[0133] 3. Comprising component F), component F) is at least one metal compound, preferably selected from metal salts such as colored or colorless metal oxides excluding silica, and preferably at least one metal compound F) is a colorless metal oxide, preferably aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide and zinc oxide, and mixtures thereof, a colored metal oxide, preferably oxides of transition metal compounds and mixtures thereof, for example, iron oxide pigments (for example, yellow iron oxide, red iron oxide, black iron oxide and mixtures thereof), mixed-phase metal oxide pigments, for example, CoAl2O4 and Co(Al,Cr)2O4, synthetic and natural ultramarine, and chromium oxide, a curable silicone rubber composition according to any of the foregoing embodiments, selected from the group consisting of mixtures of the colorless metal oxide and the colored metal oxide.

[0134] 4. A curable silicone rubber composition according to any of the foregoing embodiments, comprising component E) which is melamine cyanurate.

[0135] 5. A curable silicone rubber composition according to any of the foregoing embodiments, comprising at least one metal compound F) defined in Embodiment 3 and E) melamine cyanurate.

[0136] 6. The curable silicone rubber composition according to any of the foregoing embodiments, which does not contain calcium hydroxide and preferably does not contain alkali and alkaline earth metal hydroxides.

[0137] 7. The alkenyl group R in component A2) 1 The molar ratio to the alkenyl group in component A1) is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5, of the curable silicone rubber composition according to any of the foregoing embodiments.

[0138] 8. The curable silicone rubber composition according to any of the foregoing embodiments, containing component E), melamine cyanurate, in an amount of less than 5 parts by weight, preferably less than 2 parts by weight, based on 100 parts by weight of the total amount of components A) and B).

[0139] 9. The organohydrogensiloxane B) is selected from the group consisting of a resinous organohydrogensiloxane having terminal SiH groups with B1)>2, and an organohydrogensiloxane having two or more SiH groups and different from B1), of the curable silicone rubber composition according to any of the foregoing embodiments.

[0140] 10. The organohydrogensiloxane B) contains at least two different organohydrogensiloxanes, of the curable silicone rubber composition according to any of the foregoing embodiments.

[0141] 11. The transition metal catalyst C) is selected from hydrosilylation catalysts containing at least one metal selected from the group consisting of platinum, rhodium, palladium, ruthenium and iridium, of the curable silicone rubber composition according to any of the foregoing embodiments.

[0142] 12. The hydrosilylation catalyst C) contains platinum, of the curable silicone rubber composition according to any of the foregoing embodiments.

[0143] 13. The reinforcing filler D) is 50 to 500 m 2A curable silicone rubber composition according to any of the foregoing embodiments, selected from the group of fumed silica and precipitated silica, having a BET of / g.

[0144] 14. A curable silicone rubber composition according to any of the foregoing embodiments, wherein at least one reinforcing filler D) is selected from surface-treated fillers.

[0145] 15. A curable silicone rubber composition according to any of the foregoing embodiments, wherein at least one reinforcing filler D) is a silica filler surface-treated with at least one silazane.

[0146] 16. A curable silicone rubber composition according to any of the foregoing embodiments, wherein at least one reinforcing filler D) is a surface-treated silica filler, which is surface-treated in a two-step process involving a subsequent reaction of said filler with at least two charges of silazane.

[0147] 17. At least one reinforcing filler D) is a surface-treated silica filler, which a) providing a mixture comprising components A), B) and at least one silica filler D); b) adding to said mixture at least one silazane having at least one alkenyl group and at least one silazane having no alkenyl group; c) heating at at least 100 °C for at least 1 hour; d) removing volatile substances, and e) further adding at least one silazane preferably having no alkenyl group; f) heating at at least 100 °C for at least 1 hour, and g) removing volatile substances, to obtain a curable silicone rubber composition according to any of the foregoing embodiments.

[0148] 18. At least one metal compound F) is Those selected from the group consisting of colorless metal oxides, preferably aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide and zinc oxide, and mixtures thereof, Colored metal oxides, preferably oxides of transition metal compounds and mixtures thereof, such as iron oxide pigments (e.g., yellow iron oxide, red iron oxide, black iron oxide and mixtures thereof), mixed phase metal oxide pigments, such as CoAl2O4 and Co(Al,Cr)2O4, synthetic and natural ultramarine, and chromium oxide, and those selected from the group consisting of A curable silicone rubber composition according to any of the foregoing embodiments, selected from the group consisting of mixtures of the colorless metal oxide and the colored metal oxide.

[0149] 19. A curable silicone rubber composition according to any of the foregoing embodiments, wherein at least one metal compound F) is selected from the group consisting of titanium oxide and magnesium oxide.

[0150] 20. A curable silicone rubber composition according to any of the foregoing embodiments, comprising at least one auxiliary additive G), which is different from any of the other components (A1) to F) defined above, and is selected from the group consisting of low compression set additives, surface treatment agents, lubricating oils, oil bleed agents, and hydrosilylation inhibitors.

[0151] 21. A curable silicone rubber composition according to any of the foregoing embodiments, comprising at least one auxiliary additive G) selected from the group consisting of low compression set additives selected from acetylenic alcohols having the formula H-C≡C-R''-OH, where R'' is an organic group, such as 1-ethynyl-1-cyclohexanol ("ECH"), 9-ethynyl-9-fluorenol, and curing retardants or flame retardants selected from triazole compounds.

[0152] 22. A curable silicone rubber composition according to any of the foregoing embodiments, comprising at least one auxiliary additive G) selected from triazole compounds.

[0153] 23. - A total of 100 parts by weight of components A1) and A2), - 0.01 to 100 parts by weight of component B), preferably 0.01 to 50 parts by weight of component B), - Based on the weight of the transition metal and based on the total weight of components A) and B), 0.5 to 1000, preferably 1 to 100 ppm of component C), - Based on 100 parts by weight of the total amount of components A) and B), 0.01 to 100 parts by weight, preferably 10 to 100 parts by weight of component D), - Based on 100 parts by weight of the total amount of components A) and B), an amount of component E) of 0 to 5 parts by weight, preferably less than 5 parts by weight, more preferably less than 2 parts by weight; based on 100 parts by weight of the total amount of components A) and B), preferably >0 and less than 5 parts by weight, preferably less than 2 parts by weight, more preferably 0.01 to 2 parts by weight of component E), - Based on 100 parts by weight of the total amount of components A) and B), 0 to 10 parts by weight of component F); based on 100 parts by weight of the total amount of components A) and B), preferably >0 to 10, more preferably 0.01 to 10, even more preferably 0.1 to 5 parts by weight of component F), and - Based on 100 parts by weight of the total amount of components A) and B), 0 to 100 parts by weight of component G), and where components A) to G) are each as defined above, a curable silicone rubber composition according to any of the foregoing embodiments.

[0154] 24. A curable silicone rubber composition according to any of the foregoing embodiments, containing components D), E) and F) in a total amount of less than 40 parts based on 100 parts of the total amount of components A) and B) defined above.

[0155] 25. The molar ratio of all SiH groups in the composition to all groups SiR 1 to (or abbreviated as, group SiR 1The curable silicone rubber composition according to any of the foregoing embodiments, wherein the molar ratio of the SiH group to the group SiR (wherein each R is independently selected from saturated or aromatic organic groups) is ≤3, preferably ≤2, more preferably from 1.0 to 1.8.

[0156] Component A) comprising at least one component A1) and at least one component A2) defined as follows: A1) At least one polyorganosiloxane of formula (Ia),

Chemical formula

Chemical formula

[0157] 27. The alkenyl group R in component A2) 1The alkenyl group R in component A1) 1 The curable silicone rubber composition according to Embodiment 26, wherein the molar ratio to is in the range of 0.3 to 8, preferably 0.6 to 6, more preferably 1 to 5.

[0158] 28. Based on 100 parts by weight of the total amount of components A) and B), the amount of melamine cyanurate E) is less than 5 parts by weight, preferably less than 2 parts by weight, and more preferably greater than 0 and less than 5 parts by weight, more preferably less than 2 parts by weight, even more preferably 0.01 to 2 parts by weight based on 100 parts by weight of the total amount of components A) and B). The curable silicone rubber composition according to Embodiment 26 or 27 containing component E) in an amount of.

[0159] 29. The organohydrogen siloxane B) is selected from the group consisting of a resinous organohydrogen siloxane having terminal SiH groups with B1)>2 and an organohydrogen siloxane having two or more SiH groups and different from B1). The curable silicone rubber composition according to the above-described Embodiments 26 to 28.

[0160] 30. The organohydrogen siloxane B) contains at least two different organohydrogen siloxanes. The curable silicone rubber composition according to the above-described Embodiments 26 to 29.

[0161] 31. The transition metal catalyst C) is selected from hydrosilylation catalysts containing at least one metal selected from the group consisting of platinum, rhodium, palladium, ruthenium and iridium. The curable silicone rubber composition according to the above-described Embodiments 26 to 30.

[0162] 32. The hydrosilylation catalyst C) contains platinum. The curable silicone rubber composition according to the above-described Embodiments 26 to 31.

[0163] 33. The silica filler D) is 50 to 500 m 2A curable silicone rubber composition according to the aforementioned embodiments 26 to 32, selected from the group of fumed silica and precipitated silica, having a BET of / g.

[0164] 34. The silica filler D) is a curable silicone rubber composition according to the aforementioned embodiments 26 to 33, selected from surface-treated fillers.

[0165] 35. A curable silicone rubber composition according to the aforementioned embodiments 26 to 34, wherein at least one silica filler is a silica filler surface-treated with at least one silazane.

[0166] 36. A curable silicone rubber composition according to the aforementioned embodiments 26 to 35, wherein at least one silica filler is a surface-treated silica filler, which is surface-treated in a two-step process including a subsequent reaction of the filler with at least a two-charge silazane.

[0167] 37. At least one silica filler is a surface-treated silica filler, which is a) providing a mixture comprising components A), B) and at least one silica filler D); b) adding to the mixture at least one silazane having at least one alkenyl group and at least one silazane having no alkenyl group; c) heating at at least 100°C for at least 1 hour; d) removing volatile substances, and e) further adding at least one silazane preferably having no alkenyl group; f) heating at at least 100°C for at least 1 hour, and g) removing volatile substances, and is obtained by the steps of: A curable silicone rubber composition according to the aforementioned embodiments 26 to 36.

[0168] 38. At least one metal compound (F) is a colorless metal oxide selected from the group consisting of aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide, zinc oxide, and mixtures thereof, oxides of transition metal compounds and mixtures thereof, for example, iron oxide pigments (e.g., yellow iron oxide, red iron oxide, black iron oxide, and mixtures thereof), mixed-phase metal oxide pigments, for example, CoAl2O4 and Co(Al,Cr)2O4, synthetic and natural ultramarine, and chromium oxide, colored metal oxides selected from the group consisting of, and a curable silicone rubber composition according to the foregoing embodiments 26 to 37, selected from the group consisting of mixtures of colorless metal oxides and colored metal oxides.

[0169] 39. The colorless metal oxide (F) is selected from the group consisting of titanium oxide and magnesium oxide, and the colored metal oxide here is selected from iron oxide pigments, a curable silicone rubber composition according to the foregoing embodiments 26 to 38.

[0170] 40. A curable silicone rubber composition according to the foregoing embodiments 26 to 39, comprising at least one auxiliary additive (G) selected from the group consisting of low compression set additives, surface treatment agents, lubricating oils, oil bleed agents, hydrosilylation inhibitors, different from components A1) to F).

[0171] 41. An acetylene alcohol having the formula H-C≡C-R''-OH, where R'' is an organic group, for example, a low compression set additive selected from 1-ethynyl-1-cyclohexanol ("ECH"), 9-ethynyl-9-fluorenol, and a curable silicone rubber composition according to the foregoing embodiments 26 to 40, comprising at least one auxiliary additive (G) selected from the group consisting of a curing retarder or a flame retardant selected from triazole compounds.

[0172] 41. - A total of 100 parts by weight of components A1) and A2), 0.01 to 100 parts by weight, preferably 0.01 to 50 parts by weight, of component B), 0.5 to 1000, preferably 1 to 100 ppm of component C), based on the weight of the transition metal and based on the total weight of components A) and B), - 0.01 to 100 parts by weight of component D), based on 100 parts by weight of the total amount of components A) and B), - 0.01 to 2 parts by weight of component E), based on 100 parts by weight of the total amount of components A) and B), - 0.01 to 10 parts by weight of component F), based on 100 parts by weight of the total amount of components A) and B), - 0 to 100 parts by weight of component G), based on 100 parts by weight of the total amount of components A) and B). 42. The curable silicone rubber composition according to any preceding embodiment 26 to 41, comprising:

[0173] 43. A curable silicone rubber composition according to any of the previous embodiments, comprising D), E) and F) in an amount of less than 40 parts combined, based on 100 parts combined of components A) and B).

[0174] 44. A cured silicone rubber composition obtained by curing a curable silicone rubber composition according to any of the preceding embodiments.

[0175] 45. A cured silicone rubber composition according to any of the preceding embodiments having a compression set of 30 percent or less, preferably 25 percent or less, and more preferably 20 percent or less after 144 hours at 175°C, or 50 percent or less, preferably 40 percent or less after 1000 hours at 175°C.

[0176] 46. A cured silicone rubber composition according to any of the previous embodiments, having a compression set value of 50 percent or less, preferably 40 percent or less, after 1000 hours of testing at 175°C.

[0177] 47. A curable silicone rubber composition that can be cured by vulcanizing a cured composition having at least one compression set value selected from the group of compression set values of 30% or less, preferably 25% or less, more preferably 20% or less after a 144-hour test at 175°C, and 50% or less, preferably 40% or less after a 1000-hour test at 175°C, and Component A * ): 100 parts by weight of at least one polyorganosiloxane having at least one alkenyl group, where Component A * ) is preferably defined as Component A) above, Component B * ): 0.01 to 100 parts by weight of at least one organohydrogensiloxane having at least two SiH groups, where Component B * ) is preferably defined as Component B) above, Component C * ): At least one transition metal catalyst, where Component C * ) is preferably defined as Component C) above, Component D * ): 0.01 to 100 parts by weight of a reinforcing filler having a BET surface area of at least 50 m 2 / g, where Component D * ) is preferably defined as Component D) above, and Component H): Optionally up to 100 parts by weight of one or more selected from Components E) to G) defined above, where preferably Component H) is Component E): Melamine cyanurate defined above; Component F): At least one metal compound, preferably selected from metal salts such as colored or colorless metal oxides excluding the silica defined above, and Component G): Optionally containing or consisting of one or more auxiliary additives defined above, A curable silicone rubber composition containing

[0178] 48. Automobile parts such as connector seals; electrical and electronic parts; packaging parts; construction parts such as sealants; household parts; use of any of the curable silicone rubber compositions of the preceding embodiments or any of the cured silicone rubber compositions of the preceding embodiments for the manufacture of gasket seals, most preferably for the manufacture of shield connector assemblies for automotive applications in particular.

Examples

[0179] Unless otherwise indicated, all parts are parts by weight. Unless otherwise indicated, all percentages are weight percentages.

[0180] Example 1 The curable silicone rubber composition according to the present invention was prepared according to the following process.

[0181] Preparation of Part A) In a dissolution mixer, 17.66 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (Component A1)) having a viscosity of 10 Pa·s (U10) and 29.88 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (Component A1)) having a viscosity of 65 Pa·s (U65) were mixed with 5.09 parts of hexamethyldisilazane (part of the surface treatment agent - Component D), 0.22 parts of divinyldimethyltetrasilazane (part of the surface treatment agent - Component D), and 1.92 parts of water (additive - Component G)). Next, this mixture was mixed with 25.12 parts of fumed silica (Aerosil® 300 manufactured by Evonik) (Component D)) having a Brunauer-Emmett-Teller (BET) specific surface area of 300 m / g and heated at 100 °C for 1 hour to form a silica filler having a mixture of trimethylsilyl groups and vinyldimethylsilyl groups on its surface. The volatile compounds resulting from the water and the surface treatment reaction were then removed from the silicone mixture under vacuum (<80 mbar) at about 150 °C for 1 hour.

[0182] As a second processing step, a part of 1.31 parts of hexamethyldisilazane (Component D) was added to the mixture again, and the mixture was further heated at 100 °C for 30 minutes. The resulting volatile substances were removed from the silicone mixture at about 150 °C under vacuum (<80 mbar) for 1 hour.

[0183] The mixture was subsequently cooled and diluted with 16.77 parts of Silopren* U10 and 2.04 parts of PH300 (phenylsiloxane lubricating oil - Component G).

[0184] Subsequently, 4 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) (V5000 - Component A2) with a vinyl content of 0.85 mmol / g and a viscosity of 5 Pa·s and 2 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) (V200 - Component A2) with a vinyl content of 2.08 mmol / g and a viscosity of 2 Pa·s were added. Finally, 0.93 parts of a solution of a Pt 0 complex containing 2 wt% of Pt with tetramethyl-tetravinylcyclotetrasiloxane was added (Ashby catalyst).

[0185] Finally, 5 parts of melamine cyanurate color paste CP1 (40 wt% melamine cyanurate and 60 wt% U10 (dimethylvinylsiloxy-terminated polydimethylsiloxane (Component A1)) having a viscosity of 10 Pa·s), and 4 parts of color paste CP2 (derived from 61.2 parts of U10 (dimethylvinylsiloxy-terminated polydimethylsiloxane (Component A1))), 37.6 parts of titanium dioxide, and 1.1 parts of cyanmelamine cyanurate) were added to the mixture.

[0186] Preparation of Part B) In a dissolution mixer, 17.58 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (U10) having a viscosity of 10 Pa·s (Component A1)) and 31.62 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (U65) having a viscosity of 65 Pa·s (Component A1)) were mixed with 4.88 parts of hexamethyldisilazane (a part of Component D), 0.21 parts of divinyldimethylsilazane (a part of Component D), 0.34 parts of triazole (25 wt% aqueous solution) (Component G)), and 1.85 parts of water (Component G)). Next, this mixture was mixed with 24.27 parts of fumed silica (Aerosil® 300 manufactured by Evonik) (Component D)) having a Brunauer-Emmett-Teller (BET) specific surface area of 300 m 2 / g and heated at 100 °C for 1 hour to form a silica filler having a mixture of trimethylsilyl groups and vinyldimethylsilyl groups on its surface. Subsequently, water and volatile compounds resulting from the silylation reaction were removed from the silicone mixture at about 150 °C under vacuum (<80 mbar) for 1 hour.

[0187] As a second treatment step, 1.33 parts of hexamethyldisilazane (a part of Component D)) was added to the mixture again and heated at 100 °C for an additional 30 minutes. The resulting volatile substances were removed from the silicone mixture at about 150 °C under vacuum (<80 mbar) for 1 hour.

[0188] The mixture was then cooled and diluted with 15.86 parts of Silopren* U10 (Component A1)) and 2.06 parts of PH300 (phenylsiloxane lubricating oil - Component G)).

[0189] Subsequently, 5 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) (V5000 - Component A2) with a vinyl content of 0.85 mmol / g and a viscosity of 5 Pa·s, and 2 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) (V200 - Component A2) with a vinyl content of 2.08 mmol / g and a viscosity of 2 Pa·s were added. Finally, 0.5 part of dimethylhydrosilyl-terminated poly(dimethylsiloxane) (Component B) with an SiH content of 1.43 mmol / g and a viscosity of 0.014 Pa·s, 3 parts of a resin crosslinking agent (- Component B) with an SiH content of 9.15 mmol / g and a viscosity of 0.03 Pa·s, and 0.11 part of 1-ethynyl-1-cyclohexanol (Component G)) were added.

[0190] The cured silicone rubber composition according to the present invention was prepared as follows. Part A and Part B were mixed at a weight ratio of 1:1 and cured by heating at 175°C for 10 minutes.

[0191] The molar ratio of SiH to Si-vinyl in the entire composition (Parts A and B) was 1.23.

[0192] The measurement of the compression set of the cured silicone rubber composition was carried out in accordance with DIN ISO 815-1 as described above. Table 1 summarizes the composition of Example 1.

Table 1A

Table 1B

[0193] Example 2 In the same manner as in Example 1, the following composition was prepared. Table 2 summarizes the composition of Example 2.

Table 2A

Table 2B

[0194] Example 3 In the same manner as in Example 1, the following compositions were prepared. The compositions of Example 3 were summarized in Table 3.

Table 3A

Table 3B

[0195] Example 4 In the same manner as in Example 1, the following compositions were prepared. The compositions of Example 4 were summarized in Table 4.

Table 4A

Table 4B

[0196] Example 5 Color paste CP3 reddish brown (consisting of 77 parts of U10, 0.4 part of A150 (Aerosil with a BET surface area of 150 m 2 / g), and 22.6 parts of Bayferrox 140 M (Bayer pigment of the Fe2O3 system)) was added, and in the same manner as in Example 1, the following compositions were prepared.

[0197] The compositions of Example 5 were summarized in Table 5.

Table 5A

Table 5B

Claims

Claim 1: A colorless curable silicone rubber composition, which is vulcanized and cured to a cured composition having at least one compression set value selected from the group of compression set values of 30% or less after a test at 175°C for 144 hours and 50% or less after a test at 175°C for 1000 hours, measured in accordance with INTERNATIONAL STANDARD ISO 815-1 First Edition 2008-02-01, A) 100 parts by weight of at least one alkenyl group R １ at least one polyorganosiloxane having B) 0.01 to 100 parts by weight of at least two organohydrogensiloxanes having at least two SiH groups, wherein component B) is at least two polyorganosiloxanes of general formula (2), B1) an organohydrogensiloxane having more than 2 terminal SiH groups, and, B2) an organohydrogensiloxane having 2 or more SiH groups and different from B1), and here, B1) is an organohydrogensiloxane having terminal SiH groups of >2, containing at least one unit selected from T, T ＊ and Q. [M ａ D ｂ T ｃ Q ｄ Z ｅ ｍ (2)​ where M=R ３ SiO １／２ , and / or M ＊ D = R ２ SiO ２／２ 、and / or D ＊ T = RSiO ３／２ , and / or T ＊ Q=SiO ４／２ 、 Here, M ＊ =HR ２ SiO １／２ , D ＊ = HRSiO ２／２ , T ＊ = HSiO ３／２ , Z is a divalent optionally substituted hydrocarbyl bridging group having at most 14 carbon atoms between two siloxy groups, the siloxy groups being as defined above, and R is independently selected from saturated or aromatic organic groups, a = 0.01 - 10, b = 0 - 1000, c = 0 - 50, d = 0 - 5, e = 0 - 3, m = 1 - 1000, However, M ＊ , D ＊ and T ＊ are such that there are at least two groups selected from them, C) at least one transition metal catalyst selected from the group consisting of at least one of platinum, rhodium, palladium, ruthenium and iridium, D) 0.01 to 100 parts by weight, based on 100 parts by weight of the total amount of components A) and B), of at least 50 ml ２ at least one reinforcing filler selected from the group of fumed silica, precipitated silica, and surface-treated silica fillers having a BET surface area of 1 / g; and G) optionally up to 100 parts by weight of one or more auxiliary additives, where component A) comprises at least one component A1) and at least one component A2), which are defined as follows, A1) at least one polyorganosiloxane of formula (Ia), 【Number】 wherein each R is independently selected from saturated or aromatic organic groups, and each R １ is independently selected from kenyl groups, and x is ≧0, A2) at least one polyorganosiloxane of formula (Ib), 【Number】 Here, x, R and R １ are as defined above; R ２ is selected from R or R １ and y is ≥ 1, and the molar ratio of the alkenyl group R １ in component A2) to the alkenyl group R １ in component A1) is in the range of 0.3 to 8, and where the composition satisfies one, or two or more, of the following requirements a) to c), a) the molar ratio of all SiR groups of all SiH groups in the composition (or, abbreviated, the molar ratio of SiH groups to the SiR group) is from 1.0 to 1.8; and １ (R １ is as defined above), and １ is from 1.0 to 1.8; and b) The important impact factor KpSiH (mmol / g) defined below is 2.5 to 17.5 mmol / g; 【Number 1】 where - "Parts B i " is the weight percent of the ith component B) based on the total weight of the composition; - "SiHof B i " is the SiH content (mmol / gram) of the i-th component B), - "SiH(B i )" is the number of SiH groups of the i-th component B per molecule, - "SiH / SiR 1 " is as defined in item a) above, 【Number 2】 where D is R in component B) ２ SiO ２／２ and M is R in component B) ３ SiO １／２ and D ＊ is HRSiO in component B) ２／２ and M ＊ is the HR in component B) ２ SiO １／２ where R is as defined above, and P of each i-th component B) with the required units ｉ (D ＊ D ＊ ) is between 0 and 1, c) Alkenyl groups R in component A2) １ The alkenyl group R １ The molar ratio to is in the range of 0.3 to 8, Curable silicone rubber composition.

2. At least one reinforcing filler D) is from 50 to 500 m ２ 10. The curable silicone rubber composition of claim 1, having a BET of 100 / g.

3. 3. The curable silicone rubber composition of claim 1, comprising component F) selected from at least one metal compound selected from colored or colorless metal oxides excluding silica, wherein the at least one metal compound F) is selected from the group consisting of colorless metal oxides, colored metal oxides, mixed phase metal oxide pigments, and mixtures of said colorless metal oxides and said colored metal oxides, and wherein the amount of component F) is 0.01 to 10 parts by weight, based on 100 parts by weight of the total amount of components A) and B).

4. 4. The curable silicone rubber composition according to claim 1, comprising component E), which is melamine cyanurate, in an amount of 0.01 to 2 parts by weight, based on 100 parts by weight of the total amount of components A) and B).

5. 3. The curable silicone rubber composition of claim 1 or 2, further comprising at least one metal compound F) as defined in claim 3 and E) melamine cyanurate; Here, the colorless metal oxide is selected from the group consisting of aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide, and zinc oxide and mixtures thereof, the colored metal oxide is selected from the group consisting of yellow iron oxide, red iron oxide, black iron oxide, and mixtures thereof, and the mixed-phase metal oxide pigment is CoAl ２ O ４ and Co(Al,Cr) ２ O ４ , selected from the group consisting of synthetic and natural ultramarine, and chromium oxide.

6. The curable silicone rubber composition according to any one of claims 1 to 5, which is free of alkali and earth alkali metal hydroxides.

7. The curable silicone rubber composition according to any one of claims 1 to 6, wherein the transition metal catalyst C) is selected from platinum-containing hydrosilylation catalysts.

8. 8. The curable silicone rubber composition of claim 1, further comprising at least one co-additive G), different from any of the other components (A1) to F) defined above, selected from the group consisting of low compression set additives, surface treatment agents, lubricants, oil-bleed agents, and hydrosilylation inhibitors.

9. a total of 100 parts by weight of components A1) and A2), 0.01 to 50 parts by weight of component B), 0.5 to 1000 ppm of component C), based on the weight of the transition metal and based on the total weight of components A) and B). 0.01 to 100 parts by weight of component D), based on 100 parts by weight of the total amount of components A) and B). 0.01 to 2 parts by weight of component E), based on 100 parts by weight of the total amount of components A) and B). 0.01 to 10 parts by weight of component F), based on 100 parts by weight of the total amount of components A) and B), and 0 to 100 parts by weight of component G), based on 100 parts by weight of the total amount of components A) and B). wherein components A) to G) are each as defined above. The curable silicone rubber composition according to any one of claims 1 to 8, comprising:

10. 10. The curable silicone rubber composition according to claim 1, further comprising less than 40 parts in total of components D), E), and F), as defined above, based on 100 parts in total of components A) and B), as defined above.

11. E) Melamine cyanurate: F) at least one metal compound selected from colored or colorless metal oxides, excluding silica; G) optionally containing one or more auxiliary additives; and Here, the base SiR １ The curable silicone rubber composition according to claim 1, wherein the molar ratio of the SiH group to is from 1.0 to 1.

8.

12. Alkenyl groups R in component A2) １ The alkenyl group R １ 12. The curable silicone rubber composition of claim 11, wherein the molar ratio of

13. 13. The curable silicone rubber composition of claim 11 or 12, comprising melamine cyanurate E) in an amount of 0.01 to 2 parts by weight, based on 100 parts by weight of the total amount of components A) and B).

14. 14. The curable silicone rubber composition of claim 11, wherein the organohydrogensiloxane B) is selected from the group consisting of B1) an organohydrogensiloxane having >2 terminal SiH groups, and B2) an organohydrogensiloxane having two or more SiH groups and different from B1).

15. 15. The curable silicone rubber composition of claim 11, wherein the transition metal catalyst C) is selected from hydrosilylation catalysts comprising at least one metal selected from the group consisting of platinum, rhodium, palladium, ruthenium, and iridium.

16. At least one metal compound F) is a colorless metal oxide selected from the group consisting of aluminum oxide, titanium oxide, magnesium oxide, cerium oxide, zirconium oxide, tin oxide and zinc oxide, and mixtures thereof, oxides of transition metal compounds and mixtures thereof, iron oxide pigments (yellow iron oxide, red iron oxide, black iron oxide and mixtures thereof), mixed-phase metal oxide pigments, (CoAl ２ O ４ and Co(Al,Cr) ２ O ４ ), synthetic and natural ultramarine, and chromium oxide, and a colored metal oxide selected from the group consisting of a mixture of a colorless metal oxide and a colored metal oxide, the curable silicone rubber composition according to any one of claims 11 to 15.

17. 17. The curable silicone rubber composition of claim 16, wherein the colorless metal oxide is selected from the group of titanium oxide and magnesium oxide, and the colored metal oxide is selected from iron oxide pigments.

18. 18. The curable silicone rubber composition of claim 11, further comprising at least one co-additive G) different from components A1) to F) and selected from the group consisting of low compression set additives, surface treatment agents, lubricating oils, oil-bleed agents, and hydrosilylation inhibitors.

19. 19. The curable silicone rubber composition of any one of claims 11 to 18, comprising a low compression set additive selected from acetylenic alcohols having the formula H-C≡C-R″-OH, where R″ is an organic group, and at least one co-additive selected from the group consisting of cure retarders or flame retardants selected from triazole compounds.

20. - A total of 100 parts by weight of components A1) and A2), - 0.01 to 100 parts by weight of component B), - Based on the weight of the transition metal and based on the total weight of components A) and B), 0.5 to 1000 ppm of component C), - Based on 100 parts by weight of the total amount of components A) and B), 0.01 to 100 parts by weight of component D), - Based on 100 parts by weight of the total amount of components A) and B), 0.01 to 2 parts by weight of component E), - Based on 100 parts by weight of the total amount of components A) and B), 0.01 to 10 parts by weight of component F), - Based on 100 parts by weight of the total amount of components A) and B), 0 to 100 parts by weight of component G), the curable silicone rubber composition according to any one of claims 11 to 19.

21. A cured silicone rubber composition obtained by curing the curable silicone rubber composition according to any one of claims 11 to 20.

22. Measuring the compression set according to INTERNATIONAL STANDARD ISO 815-1 first edition 2008-02-01, having a compression set of 30% or less after a test at 175°C for 144 hours, or 50% or less after a test at 175°C for 1000 hours, the cured silicone rubber composition according to claim 21.

23. Use of the curable silicone rubber composition according to any one of claims 1 to 22 for the manufacture of connector seals for automotive applications; electrical and electronic components; packaging components; seals for construction components; household components; and gasket seals.

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