Non-curing silicone composition containing carbon black

Abstract

A process for the production of a non-curable silicone composition containing carbon black, and its use in the production of a curable silicone composition, particularly for use in high voltage direct current (HVDC) applications.

Description

[Technical Field]

[0001] The present invention relates to a process for producing a non-curable silicone composition containing carbon black, the non-curable silicone composition obtained by the process, and its use for producing a curable silicone composition, particularly for applications using high-voltage direct current. [Background technology]

[0002] Standard silicones are widely used in the high-voltage (HV) industry for alternating current (AC). However, the use of these materials is not suitable for the latest trends in direct current (DC) applications. Using carbon black (CB) as a filler material brings beneficial properties to silicones, and positive test results have been obtained for standard CB pastes, which have been established over many years, at operating voltages up to 325kV. This standard CB paste is manufactured using three-roll mill technology or twin-screw (blade) kneaders (US2017 / 0372815A1).

[0003] However, the inventors have found that at high voltages up to 500kV, there is a limit due to dielectric breakdown occurring in the modified silicone system.

[0004] Furthermore, current conductive liquid silicone rubber (LSR) exhibits very limited variation in mechanical properties, and in some cases, its electrical conductivity is insufficient.

[0005] Silicone compositions containing carbon black as a filler are disclosed, for example, in the following advanced technical literature:

[0006] WO2016 / 110570 and US2017 / 0372815A1 are, respectively, a) At least one polyorganopolysiloxane having an alkenyl group, b) A crosslinking agent component containing one or more polyorganohydrogensiloxanes, c) A filler containing one or more reinforcing silica or resin, d) at least one insulating compound, and e) Containing a curing catalyst, Here, the use of a silicone composition in which the insulating compound d) may be selected from carbon black is disclosed. That is, these disclose the use of a curable silicone composition, whereas this application deals with the use of a non-curable silicone composition.

[0007] Furthermore, WO2016 / 110570 discloses a method for manufacturing an insulator or field grading assembly, which includes molding the above-mentioned silicone composition by extruding it through a nozzle or mold, and then curing the molded composition with heat or light.

[0008] This application relates to a process comprising extruding a non-curable silicone composition containing carbon black, and to a curable silicone composition containing a specific non-curable carbon black silicone composition obtained by a process comprising an extrusion step, which consequently results in an improvement in the properties of the curable silicone composition for DC applications based on such carbon black paste. WO2016 / 110570 and US2017 / 0372815A1 disclose extrusion as a means for molding such a curable silicone composition.

[0009] US2004 / 138370A1 discloses a silicone composition for use as a conductive liquid rubber composition in, for example, a printer. a) Polyorganopolysiloxane having an alkenyl group, b) At least one insulating compound, i.e., carbon black, c) curing catalyst; d) A crosslinking agent comprising an organopolysiloxane having two or more hydrogen atoms bonded to silicon in one molecule, The components described above are preferably supplied continuously to a mixing device. This mixing device may be an extruder in particular.

[0010] Therefore, while extrusion is an essential step in providing a non-curable carbon black silicone paste, US2004 / 138370A1 discloses that the mixing step of all components constituting the curable silicone composition described herein may be performed by an extruder.

[0011] WO2020 / 063799A1 relates to a conductive liquid silicone rubber composition containing carbon black, a) One or more polydiorganosiloxanes having at least two alkenyl groups per molecule, b) at least one organohydrogenpolysiloxane, c) At least one reinforcing filler d) at least one hydrosilylation catalyst, and e) Electrically conductive filler containing the following (i) additional conductive carbon black, and (ii) Contains single-walled carbon nanotubes. That is, this relates to a curable silicone rubber composition.

[0012] With respect to such curable silicone rubber compositions, extrusion is referred to as a processing or molding means for the curable silicone rubber compositions described above, and thus serves a different purpose from that of the present application, which relates to the production of non-curable carbon black silicone masterbatches using an extrusion process.

[0013] WO2009 / 027133A2 relates to a manufacturing process for molded cured silicone articles, which includes a molding step comprising continuous molding of a curable silicone mixture. According to the disclosure in this document, a portion of the above mixture, i.e., a portion of the uncured mixture of components, (i) at least one linear polyorganosiloxane having at least three alkenyl groups and having an average number of diorganosiloxy units determined by GPC with polystyrene as the standard, (ii) Optionally, one or more polyorganosiloxanes having alkenyl groups, different from the polyorganosiloxane of component (i), (iii) at least one polyorganosiloxane having at least two SiH groups, (iv) at least one photoactivatable transition metal catalyst, (v) Optionally one or more fillers, (vi) optionally comprising one or more conventional additives, It is soluble in CDCl3 at 25°C and contains less than 0.025 mol% of vicinal Si-alkenyl groups.

[0014] In contrast to the inventions contained herein relating to a process for producing a non-curable silicone composition containing carbon black, the above-described mixture of compounds (i) to (vi) means a curable mixture containing all the compounds required for curing the silicone composition: (i) alkenyl polysiloxane, (iii) SiH-functionalized polysiloxane, and (iv) a photoactivatable transition metal catalyst.

[0015] In the mixture of the process of the present invention, the presence of carbon black is essential, but the presence of the filler component (v) in the above mixture is optional.

[0016] Furthermore, WO2009 / 027133A2 refers to a process involving the continuous molding of the above-mentioned mixture, where the continuous molding step of the uncured mixture is an extrusion step, and therefore the molding apparatus is an extruder. The examples in WO2009 / 027133 illustrate the extrusion of a curable silicone composition.

[0017] In contrast to the disclosure of WO2009 / 027133A2, this application relates to a process for manufacturing a composition, comprising the extrusion of one or more polyorganosiloxanes and one or more carbon blacks, i.e., it relates to a process comprising the extrusion of a non-curable composition. [Overview of the project]

[0018] Thus, the inventors conducted detailed studies and improved upon the shortcomings of advanced silicone compositions in terms of electrical and mechanical properties.

[0019] Surprisingly, the inventors found that CB paste behaves significantly differently when processed by extrusion compared to conventional CB paste. CB nanoparticles are dispersed much more uniformly within the silicone material, resulting in several remarkably improved electrical properties in the cured silicone rubber composition prepared therefrom. Furthermore, the extrusion process achieves a finer particle size dispersion of CB than is possible with CB paste prepared by conventional methods.

[0020] Compared to conventionally prepared CB pastes, the novel CB paste of the present invention allows for the incorporation of a greater amount of carbon black into the cured silicone rubber composition without reaching the so-called critical percolation threshold at which the resistance value drops sharply. This allows for the incorporation of more carbon black into the cured silicone composition when used as an insulator at similarly high (or higher) resistance levels. In line with this, the cured silicone rubber composition will contain a higher concentration of charge traps, which will reduce electrical stress, particularly under DC conditions. Thus, the electrical properties of the resulting cured silicone composition provide greater reliability to DC systems at ultra-high voltages (such as 500kV) where market demand exists.

[0021] Furthermore, with respect to electrically conductive silicone rubber compositions, the use of the novel CB paste of the present invention allows for the incorporation of a larger amount of carbon black into the curable silicone. Thus, the extruded CB paste allows for the use of a high CB concentration in conductive LSR, thereby improving the mechanical properties. This makes it possible to provide a silicone rubber composition with good mechanical properties and very high electrical conductivity, especially for use in high-voltage DC applications, particularly for use in one or more layers in cable accessories, if necessary.

[0022] The present invention provides a process for producing a non-curing silicone composition containing carbon black, the process comprising extruding one or more polyorganosiloxanes a1) together with one or more carbon blacks d).

[0023] According to the present invention, the term "non-curable silicone composition" is intended to mean that the silicone composition does not contain the components necessary to cure the silicone composition under normal polysiloxane curing conditions. Assuming normal silicone rubber curing modes such as hydrosilylation curing systems like platinum-catalyzed curing systems or addition curing systems, condensation curing systems, peroxide curing systems, or oxime curing systems, the non-curable silicone composition obtained by the present invention does not contain the components necessary for curing, especially in the extrusion process. Therefore, in hydrosilylation curing systems such as platinum-catalyzed addition curing systems, the non-curable silicone composition cannot simultaneously contain hydride-functional, alkenyl-functional polysiloxane and hydrosilylation catalyst, and preferably contains only alkenyl-functional polysiloxane. Similarly, the non-curable silicone composition cannot contain peroxides for curing polyorganosiloxane a1). Therefore, the non-curable silicone composition of the present invention preferably does not contain polyorganohydrogensiloxane or hydrosilylation curing catalyst, and more preferably does not contain either polyorganohydrogensiloxane or hydrosilylation curing catalyst, nor does it contain peroxide.

[0024] In a preferred embodiment, the overall viscosity of one or more polyorganosiloxanes a1) is less than 100 Pa·s, preferably 1 to 100 Pa·s, more preferably 5 to 100 Pa·s, and even more preferably 10 to 65 Pa·s (each measured, for example, by DIN EN ISO3219, at a shear rate D=10s at 20°C). -1(Measured by ). In this regard, the term "overall viscosity" refers to the viscosity of all polyorganosiloxanes a1) when more than one polyorganosiloxane is used, and refers to the viscosity of one polyorganosiloxane a1) when only one polyorganosiloxane a1) is used. In the former case, the viscosity of individual polyorganosiloxanes a1) may deviate from the preferred viscosity range shown above. In a preferred embodiment, polyorganosiloxane a1) is selected from polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups as described later. Such polyorganosiloxanes a1) have an organic substituent R preferably selected from the group consisting of optionally substituted alkyls such as alkyl groups and halogenated alkyl groups, optionally substituted aryls such as phenyl, and an unsaturated substituent R preferably selected from groups consisting of alkenyl groups such as vinyl groups. 1 It has an average degree of polymerization P between 100 and 12000 siloxy units. n The polyorganosiloxane a1) can be referred to as a polyorganosiloxane a2) having an alkenyl group, which is used in curable silicone compositions as described below. The process according to the present invention involves mixing one or more polyorganosiloxanes a1) with one or more carbon blacks d) and extruding them.

[0025] Basically, several types of extruders may be used, such as the commonly known single-screw extruder, twin-screw extruder, and planetary roller extruder. Of these, the single-screw extruder is not very preferred because of its poor uniformity and dispersibility. The planetary roller extruder has extremely good mixing performance compared to all other types of extruders, but its conveying performance is much lower. Therefore, in the present invention, a twin-screw extruder, particularly a twin-screw extruder that rotates simultaneously, is preferred from the viewpoint of uniformity and dispersibility on the one hand, and conveying performance on the other hand. Basically, it is possible to prepare a premixture of components a1) and d) and then feed it into the extruder by a suitable dispensing device, but a process of dispensing components a1) and d) separately via at least two, preferably two, dispensing devices is preferred. Preferably, the extruder has two feed compartments, one of which is preferably for polyorganosiloxane a1), which usually forms a viscous fluid at room temperature. It may be supplied using a twin-screw feeder, such as a twin-screw loss-in-weight feeder, or a dosing system such as a piston drum or gear pump. One or more carbon blacks d) are supplied by one or more, preferably one or two, dosing devices such as gravimetric feeders located downstream of the polyorganosiloxane feeder. To enable distributive and dispersed mixing of the carbon blacks and polyorganosiloxane, the carbon black dosing device is preferably located at a point in the extruder where the polyorganosiloxane is completely liquid.

[0026] Extrusion is typically carried out when the extruded mass is at a temperature between room temperature (25°C) and 250°C, preferably between 50°C and 200°C. The melting and homogenization process in the extruder is preferably carried out without adding heat generated by the shear forces within the extruder. External heat can be optionally supplied, but more preferably, external cooling means are provided to prevent the process from reaching temperatures that could lead to the decomposition of the polyorganosiloxane, particularly at high carbon black additions. Preferably, extrusion is carried out using one or more of the following conditions: • Two-screw system rotating simultaneously, • Screw diameter in the range of 15mm to 250mm, preferably 20mm to 100mm. • A supply speed of approximately 1 kg / hour to 600 kg / hour, preferably 100 kg / hour to 550 kg / hour, more preferably 10 kg / hour to 50 kg / hour. Screw speed of 50 rpm to 1200 rpm, preferably 100 rpm to 1000 rpm. • Extrusion temperature from 50°C to 200°C L / D ratio of 20 to 80, preferably 30 to 70, (where L is the length of the extruder and D is its diameter) • Residence time of 10 seconds to 10 minutes, preferably 15 seconds to 2 minutes. • Use of cylinder cooling, • Segmented design with a geometric shape that allows for powerful dispersion of the screw element.

[0027] A preferred extruder is, for example, the ZSE MAXX series twin-screw extruder from Leistritz Extrusion Technik GmbH in Nuremberg, Germany, with a screw diameter of 15 mm to 250 mm, preferably 20 mm to 100 mm, and using a high-dispersion screw.

[0028] In the extrusion process of the present invention, the weight ratio of one or more polyorganosiloxane a1) to one or more carbon black d) is preferably 90:10 to 75:25, preferably 89:11 to 80:20, and more preferably 88:12 to 81:19.

[0029] In preferred embodiments, only one or more polyorganosiloxanes a1) and one or more carbon blacks d) are extruded; in other words, no other components are present in the extrusion process. Alternatively, in preferred embodiments, only one type of polyorganosiloxane a1) and one type of carbon black d) are extruded, resulting in a masterbatch having a high concentration of carbon black in the polysiloxane and a finer, more uniform particle size distribution than that achieved by conventional processes.

[0030] In a further embodiment, the present invention relates to a non-curable silicone composition obtained by the process of the present invention. Such “non-curable composition” may also be referred to as a “masterbatch.”

[0031] The non-curing silicone composition according to the present invention preferably contains one or more carbon blacks d) in an amount of at least 10 weight percent, preferably at least 11 weight percent, more preferably at least 12 weight percent, even more preferably at least 13 weight percent, and still more preferably at least 14 weight percent, based on the total weight of the entire silicone composition.

[0032] The non-curing silicone composition according to the present invention preferably contains one or more carbon blacks d) in an amount of 10 to 25 weight percent, preferably 11 to 24 weight percent, more preferably 12 to 23 weight percent, more preferably 13 to 22 weight percent, and even more preferably 14 to 21 weight percent, based on the total weight of the entire silicone composition.

[0033] Generally, the "non-curable composition" or carbon black "masterbatch" preferably contains 10 to 25 weight percent of one or more carbon blacks d) based on the total weight of the entire silicone composition, but if necessary, the non-curable composition may also be prepared with a smaller amount of carbon black, for example, 3 to 10 weight percent of one or more carbon blacks d) based on the total weight of the entire silicone composition. Furthermore, non-curable compositions with a smaller amount of carbon black enjoy the advantage of a more uniform and fine particle size distribution achieved by the extrusion process.

[0034] Preferably, the non-curable silicone composition according to the present invention comprises one or more polyorganosiloxanes a1) and one or more carbon blacks d), and more preferably it comprises one type of polyorganosiloxane a1) and one type of carbon black d).

[0035] In this invention, one or more carbon blacks d) are preferably >30m 2 BET specific surface area and average primary particle diameter D from 5nm to 500nm per g 50 It comprises at least one carbon black selected from conductive carbon blacks having the following properties. More preferably, the carbon black component d) in the non-curable composition according to the present invention is >30m 2 BET specific surface area and / or average primary particle diameter D from 5 nm to 500 nm per g 50It consists of conductive carbon black having [a certain property]. Generally, in the non-curable silicone composition of the present invention, the primary particle size and the aggregated particle size of the carbon black must be distinguished. The particle size or diameter of the basic carbon black primary particles is well in the range of 5 nm to 500 nm, but the aggregated particle size in the non-curable silicone composition of the present invention, as determined by light scattering, is generally larger than about 0.5 μm, preferably substantially in the range of about 0.5 to about 10 μm, and more preferably substantially in the range of about 1 to about 10 μm.

[0036] The particle size distribution of carbon black in non-curing silicone compositions may be measured by light scattering according to DIN EN ISO / IEC 17025 in a toluene solution, using a scattering model that follows Mie theory, measured at the lowest rotational speed of the dispersion unit corresponding to the minimum shear force. The results are preferably presented as a superposition of one or more measurements over a time period of 5 to 15 minutes. The measurements can be performed using a zetasizer instrument from Malvern Panalytical. Such measurement methods yield either a number percentage or a volume percentage of the particle size distribution.

[0037] The extrusion process according to the present invention has been found to result in a substantial increase in the number of particles with a particle size of less than 10 μm, even when large amounts of carbon black are added, compared to conventional masterbatches produced by three-roll mill technology or twin-screw blade kneaders. Although not bound by theory, it is assumed that the extrusion process according to the present invention will result in good aggregation, de-aggregation, or dispersion of carbon black particles in CB-silicone masterbatches.

[0038] Preferably, the proportion of particles smaller than 10 μm is greater than 70%, preferably greater than 80%, and even more preferably greater than 90%. Preferably, the proportion of particles larger than 10 μm is less than 30%, preferably less than 20%, even more preferably less than 10%, and even more preferably less than 5%.

[0039] Dn of the particle number-based particle size distribution of the non-curable silicone composition 50 is preferably less than 7 µm, more preferably less than 5 µm, and most preferably less than 3 µm.

[0040] Dn of the particle number-based particle size distribution of the non-curable silicone composition 90 is preferably less than 15 µm, more preferably less than 10 µm, still more preferably less than 8 µm, and most preferably less than 5 µm.

[0041] Dn 50 is a dimension in micrometers, whose diameter splits the number distribution such that half of the particles are above and half are below this diameter. Dn 50 is used as the median for the number distribution. For Dn 90 , 90% of the particles have a dimension less than this diameter. (See https: / / www.horiba.com / uk / scientific / products / particle-characterization / education / general-information / data-interpretation / understanding-particle-size-distribution-calculations / ).

[0042] Particularly preferably in the non-curable silicone composition according to the present invention, the one or more carbon blacks comprise at least one carbon black selected from conductive carbon blacks having one or more of the following properties: · >100 m 2 / g to 1500 m 2 / g, more preferably >100 m 2 / g to 1400 m 2 / g, more preferably >100 m 2 / g to 1000 m 2 / g, more preferably >250 m 2 / g to 1000 m 2 / g, more preferably >500 m2 / g to 1000m 2 BET specific surface area / g, and / or ·D 50 Particle size between 5 nm and 500 nm, more preferably 10 nm and 200 nm, and / or DBP absorption (pore volume) of 300-600 ml / 100g, more preferably 300-550 ml / 100g, more preferably 300-400 ml / 100g, and / or Iodine adsorption amounts of 700-1200 mg / g, more preferably 700-1150 mg / g, more preferably 700-1000 mg / g, more preferably 700-900 mg / g, and / or pH 8-11, more preferably pH 9-11, more preferably pH 9-10.5 and / or • Metal content <50 ppm, and / or • Sulfur content <150 ppm, and / or • Moisture content <0.5% by weight, and / or • Volatile component content <1% by weight, and / or • The pellet contains <10% by weight of fine particles <125 micrometers, and / or • Grit content <50 mg / kg, and / or • Ash content <0.1% by weight.

[0043] Preferably, one or more carbon blacks consist of at least one, preferably one, carbon black selected from conductive carbon blacks having one or more of the properties described above.

[0044] In a further embodiment, the present invention relates to using the non-curable silicone composition defined above in the production of a curable silicone composition. Such use generally requires the non-curable silicone composition to be ultimately mixed with components required for the production of a curable silicone composition, particularly those described below. Thus, in a further embodiment, the present invention also relates to using the non-curable silicone composition defined above as a masterbatch for incorporation into a curable silicone composition. As is well known to those skilled in the art, masterbatches are typically solid additives for plastics and are used to color plastics (color masterbatches) or to impart other properties to plastics (additive masterbatches). In the present invention, the masterbatch is preferably used to incorporation one or more carbon blacks d) into the curable silicone composition as described below, but is not limited thereto.

[0045] Due to the high homogeneity of the non-curable silicone composition according to the present invention and the advantageous electrical properties obtained therefrom, the non-curable silicone composition (masterbatch) according to the present invention is particularly suitable for high-voltage DC applications, i.e., for the production of curable silicone compositions for use in high-voltage DC applications.

[0046] Therefore, in a further embodiment, the present invention relates to a curable silicone composition comprising the non-curable silicone composition according to the present invention as described above.

[0047] Particularly preferred curable silicone compositions, including the non-curable silicone composition according to the present invention: a) 100 parts by weight of one or more polyorganosiloxanes having alkenyl groups a2) b) A crosslinking agent component comprising 0 to 100 parts by weight, preferably >0 to 100 parts by weight of one or more polyorganohydrogensiloxanes. c) 0 to 100 parts by weight, preferably >0 to 100 parts by weight of one or more filler components comprising one or more reinforcing silica or resin, d) One or more carbon black in amounts of 0.1 to 3 parts by weight, preferably 0.2 to 2.8 parts by weight, more preferably 0.3 to 2.7 parts by weight, more preferably 0.4 to 2.6 parts by weight, more preferably 0.5 to 2.5 parts by weight, more preferably 0.6 to 2.3 parts by weight, more preferably 0.8 to 2.1 parts by weight. e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) Contains 0 to 50 parts by weight of one or more auxiliary additives.

[0048] Preferably, the curable silicone composition of the present invention contains a crosslinking agent component comprising one or more polyorganohydrogensiloxanes.

[0049] Preferably, the curable silicone composition of the present invention contains one or more filler components comprising one or more reinforcing silica or resin.

[0050] Such curable silicone compositions preferably contain one or more carbon blacks d) in an amount of 0.1 to 2.5 weight percent, preferably 0.2 to 2.4 weight percent, more preferably 0.3 to 2.3 weight percent, more preferably 0.4 to 2.2 weight percent, more preferably 0.5 to 2.1 weight percent, more preferably 0.6 to 2.0 weight percent, more preferably 0.7 to 1.9 weight percent, and more preferably 0.8 to 1.8 weight percent, based on the total weight of the curable silicone composition, wherein such carbon blacks d) are obtained from a non-curable silicone composition containing it, i.e., a masterbatch.

[0051] These curable silicone compositions, which contain relatively low amounts of carbon black, have relatively low conductivity and are particularly suitable as insulators or field grading assemblies for high-voltage direct current (HVDC) applications, as will be described in more detail below.

[0052] The components of the curable silicone composition according to the present invention are described below. As described above, one or more polyorganosiloxanes a1) are preferably selected from polyorganosiloxanes a2) having alkenyl groups, as described below. Polyorganosiloxanes a1) and polyorganosiloxanes a2) having alkenyl groups may be the same or different.

[0053] Polyorganosiloxane a2) containing alkenyl groups) The curable silicone composition comprises, as a base polymer, one or more polyorganosiloxane a2) having one or more alkenyl groups, preferably at least two alkenyl groups.

[0054] Preferably, polyorganosiloxane a2) is selected from the group of polyorganosiloxanes having one or more organic substituents R, i.e., having at least one carbon atom bonded to a silicon atom by the carbon atom, and optionally substituted alkyl groups such as halogenated alkyl groups such as methyl groups or fluorine-substituted propyl groups, optionally substituted aryl groups such as phenyl groups, and one or more alkenyl groups R 1 , having a group more preferably selected from the group consisting of vinyl groups, and having an average degree of polymerization (P) in which the siloxy units are between 100 and 12000, particularly calculated from the number average molecular weight obtained by GPC measurement using a polystyrene standard in accordance with ASTM D5296-11. n ) has.

[0055] The polyorganosiloxane as component a2) having alkenyl groups most preferably has at least two alkenyl groups on average.

[0056] A suitable component a2) may be described by general formula (I), (M a D b T c Q d R 2 e ) m (I) Here, the subscripts in formula (I) represent the ratios of siloxy units M, D, T, and Q, which may be distributed in a block or random manner within the polyorganosiloxane. Within the polyorganosiloxane, each siloxane unit may be identical or different, and a = 0 to 10 b = 0 to 12000 c = 0 to 50 d=0~1 e = 0 to 300 m = 1 to 1000, Here, the subscripts a, b, c, d, and m represent the viscosity of component a) at 20°C, which is 50 kPa·s (shear rate D = 10s at 20°C). -1 The value is less than (measured by), and thus not all of the subscripts a to e are 0, preferably (a+b) is > 0.

[0057] The viscosity of component a2) refers to the viscosity of a single component a2) or the viscosity of a mixture of multiple components a2). In the latter case, the mixture has a shear rate D = 10s at 20°C. -1 The present invention includes the presence of individual components a2) which may have a viscosity exceeding 50 kPa·s, for example, a2) which is a resinous component or rubber containing units Q and / or T.

[0058] In equation (I), the sum of the subscripts is equal to the number-average molecular weight M. n Average degree of polymerization P based on n It should represent this.

[0059] In equation (I): M=R3SiO 1 / 2 or M * D=R2SiO 2 / 2 Or D * T=RSiO 3 / 2 or T * Q=SiO 4 / 2 And, R 2 This is a divalent group that bridges the siloxy groups as described above, and is preferably a divalent, optionally substituted hydrocarbyl group, such as an optionally substituted alkenyl group having 2 to 10 carbon atoms, or an optionally substituted aromatic group such as an arylene group, which is bonded to the silicon atom by its own carbon atom, and Each R may be the same or different, and each is preferably an organic group selected from optionally substituted alkyl groups of up to 12 carbon atoms, or optionally substituted aryl groups of up to 12 carbon atoms, and the R group does not contain aliphatic unsaturated, During the ceremony M * =R 1 p R 3-p SiO 1 / 2 D * =R 1 q R 2-q SiO 2 / 2 T * =R 1 SiO 3 / 2 And, Here p = 0 to 3, preferably 1 to 3. q=1~2, and R 1 This is defined as above.

[0060] R is preferably normal C1 to C 12 Alkyl, iso C3-C 12 Alkyl, or tertiary C4-C 12 Alkyl, alkoxyalkyl, C5-C 12 Cyclic alkyl, or C6-C 12Selected from aryl and alkylaryl groups, these groups may be additionally substituted with one or more O atoms, Cl atoms, CN atoms, or F atoms, or poly(C2-C4) alkylene ethers up to 500 oxyalkylene units, and the R group does not contain aliphatic unsaturated groups.

[0061] Suitable examples of monovalent hydrocarbon groups include alkyl groups, preferably CH3-, CH3CH2-, (CH3)2CH-, and C8H. 17 - and C 10 H 21 - and other alicyclic groups such as cyclohexylethyl, aryl groups such as phenyl, tolyl, xylyl, and aralkyl groups such as benzyl, 2-phenylethyl, and 2-phenylpropyl. Preferred monovalent halohydrocarbon groups are those of formula C n F 2n+1 It has 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 Examples include -, C3F7-OCF(CF3)- and C3F7-OCF(CF3)-CF2-OCF(CF3)-.

[0062] In the polyorganosiloxane a2) of the curable silicone composition of the present invention, the preferred group R is selected from the group consisting of a methyl group, a phenyl group, and a 3,3,3-trifluoropropyl group, and the most preferred R group is a methyl group.

[0063] R 1 Preferably, it is selected from unsaturated groups such as groups containing a C=C group (alkenyl groups), for example: normal C2~C 14 Alkenyl, isoc3~C 14 Alkenil, or Tersari C4-C 14 Alkenyl, or C6~C 14 Cyclic alkenyl, C6~C 14 Cycloalkenyl, C8~C14 These are alkenylaryl, cycloalkenylalkyl, vinyl, allyl, methallyl, 3-butenyl, 5-hexenyl, 7-octenyl, ethylidene-norbornyl, styryl, vinylphenylethyl, norborneyl-ethyl, and limonenyl, which are optionally substituted with one or more oxygen atoms or fluorine atoms or groups (alkynyl groups) containing a CoC group, and optionally contain one or more oxygen atoms or fluorine atoms.

[0064] The alkenyl group is preferably bonded to a terminal silicon atom; due to the availability of alpha-dienes and omega-dienes used to prepare alkenylsiloxanes, the olefin function lies in the terminal alkenyl group of the higher alkenyl group.

[0065] R 1 Preferred groups are vinyl, allyl, 5-hexenyl, cyclohexenyl, limonyl, styryl, vinylphenylethyl, and most preferred R 1 The base material is vinyl.

[0066] R 2 The group includes, for example, a divalent aliphatic or aromatic normal, iso, tertiary, or cycloalkylene, arylene, or alkylenearyl group with up to 14 carbon atoms. 2 R forms a crosslinking element between two siloxy units. 2 The content of the group shall not exceed 30 mol% of the total siloxy units, preferably not exceeding 20 mol%. Preferably R 2 It does not exist. A suitable divalent hydrocarbon group R 2 Preferred examples include preferably -CH2-, -CH2CH2-, -CH2(CH3)CH-, -(CH2)4-, -CH2CH(CH3)CH2-, -(CH2)6-, -(CH2)8- and -(CH2) 18any alkylene residue such as -; a cycloalkylene group such as cyclohexylene; combinations of hydrocarbon groups such as phenylene, xylene and benzylene, that is, arylene groups such as -CH2CH2-C6H4-CH2CH2- and -C6H4CH2- are included. Preferred groups are alpha-ethylene, omega-ethylene, alpha-hexylene, omega-hexylene, 1,4-phenylene or 1,4-ethylene phenyl.

[0067] Further examples include divalent halohydrocarbon groups R 2 , for example any divalent hydrocarbon group R in which one or more hydrogen atoms are substituted by a halogen such as fluorine, chlorine or bromine 2 . Preferred divalent halohydrocarbon residues have the formula -CH2CH2(CF2) 1~10 CH2CH2-, which is for example like -CH2CH2CF2CF2CH2CH2-, or other suitable examples of divalent hydrocarbon ether groups and halohydrocarbon ether groups include -CH2CH2OCH2CH2-, -C6H4-O-C6H4-, -CH2CH2CF2OCF2CH2CH2-, and -CH2CH2OCH2CH2CH2-.

[0068] Examples of polymers containing R, R 1 and / or R 2 groups as component a2) are, for example, alkenyl-dimethylsiloxy-terminated or trimethylsiloxy-terminated polydimethylsiloxanes, which may contain other siloxane units such as poly(dimethyl-co-diphenyl)siloxane in addition to alkenylmethylsiloxy groups and dimethylsiloxy groups.

[0069] Broadly speaking, component a2) of the curable silicone composition of the present invention is oxygen and / or a divalent group R 2may be any polyorganosiloxane compound containing two or more silicon atoms linked together, wherein each silicon atom is bonded to 0 to 3 monovalent groups, with the proviso that the polyorganosiloxane compound contains at least two silicon-bonded unsaturated hydrocarbon residues including olefinic groups and acetylenic groups, and these groups are preferably, for example, alkenyl groups.

[0070] Siloxane units M, M * , D, D * , T, T * for each silicon atom, the group R and / or the group R 1 may be the same or different. In a preferred embodiment, the structure is R 1 p R 3-p SiO(R2SiO) m1 (R 1 RSiO) n SiR 1 p R 3-p (1) p=0 to 3, preferably 1, m1=0 to 12000, preferably 10 to 6000, more preferably 100 to 1000, n=0 to 5000, preferably 3 to 2000, more preferably 5 to 500.

[0071] One preferred polyorganosiloxane component a2) for the curable composition of the present invention is a substantially linear polyorganosiloxane a3). The expression "substantially linear" includes polyorganosiloxanes that do not contain more than 0.2 mol% (trace amount) of T-type or Q-type siloxy units. This means that the polymer a2) is preferably a linear flowable fluid a3), for example, the formula thereof is: R 1 p R 3-p SiO(R2SiO) m1 SiR 3-p R p 1 (1a) R in the formula 1 R, p, and m1 are defined as described above, However, each molecule contains at least two alkenyl groups.

[0072] The polyorganosiloxane a2) or a3) is most preferably selected from formula (1a).

[0073] The following are included in the preferred structure: Vi p Me 3-p SiO(Me2SiO) 10~12000 SiMe 3-p Vi p (1b) PhMeViSiO(Me2SiO) 10~12000 SiPhMeVi (1c) That is the case.

[0074] In the group of alkenyl-containing polysiloxanes a2), it is preferable to add a second or third polysiloxane as component a4) and / or component a5). The purpose of adding components a4) and a5), which are so-called vinyl-rich polymers, is to change the mechanical properties and crosslinking density.

[0075] The polymer suitable for LSR (Liquid Silicone Rubber) is P n A polymer is selected from the group of siloxane polymers having 100 to 2000 siloxy units, and a polymer suitable for HCR (high viscosity rubber described below) is preferably P n The polymer is selected from the group of siloxane polymers having 2,000 to 12,000 siloxy units.

[0076] Polymer a4) is selected from the group consisting of polymers of formula (1d) to (1i), i.e., linear polyorganosiloxanes having additional alkenyl side chain groups and having concentrations of T units and Q units of less than 0.2 mol%, or from polyorganosiloxanes having higher concentrations of T units and Q units than polymer types a2) or a3) described above.

[0077] Polymer a4) can be represented, for example, by formulas 1d) to 1f). R 1 p R 3-p (R2SiO) b1 (R 1 RSiO) b1x SiR 3-p R p 1 (1d) Me3SiO(Me2SiO) b1 (MeR 1 SiO) b1x SiMe3(1e) R 1 Me2SiO(Me2SiO) b1 (MeR 1 SiO) b1x SiMe2R 1 (1f) Here b1 => 0 to 12000, b1x = 0 to 5000, b1 + b1x = > 10 to 12000, R 1 R and p are defined as above, and R 1 Preferably, the groups R are vinyl, allyl, hexenyl, cyclohexenyl, limonyl, styryl, and vinylphenylethyl. And preferred groups for R are methyl, phenyl, and 3,3,3-trifluoropropyl.

[0078] Other preferred structures of a4 are: Vi p Me 3-p SiO(Me2SiO) 10~12000 (MeViSiO) 1~4000 SiMe 3-p Vi p (1g) Me3SiO(Me2SiO) 10~12000 (MeViSiO) 1~4000 SiMe3 (1h) PhMeViSiO(Me2SiO) 10~12000 (MePhSiO) 1~4000 SiPhMeVi (1i) Here, Me = methyl, Vi = vinyl, Ph = phenyl, and p = 0 to 3, preferably p = 1.

[0079] The third component of polymer a2), namely the branched-chain polymer a5), is preferably selected from polymers of formula (Ia), wherein the polyorganosiloxane a5) containing alkenyl groups is present in a concentration of more than 0.2 mol% T=RSiO 3 / 2 The unit or Q = SiO 4 / 2 It has units. (M 0.4~4 D 0~1000 T 0~50 Q 0~1 ) 1~1000 (Ia) Here M=R3SiO 1 / 2 or M * D=R2SiO 2 / 2 Or D * T=RSiO 3 / 2 or T * Q=SiO 4 / 2 And, Each is defined as described above. Here M * , D * and T * As defined above, the unsaturated group R 1 It has such M * Unit, D * Units and T * The amount of units is preferably 0.001 to 20 mol%, more preferably 0.01 to 15 mol%, and most preferably 0.1 to 10 mol%, based on the total siloxy units.

[0080] The range of the subscript is the number-average molecular weight M. n Possible average degree of polymerization P n It defines the scope.

[0081] These subscripts relate to the appropriate viscosity, which will be specified later, and describe the polymer without a solvent for viscosity adjustment.

[0082] Preferred branched polyorganosiloxanes a4) and a5) typically have an unsaturated group R 1 It has a high concentration of branched chain polymer a5) is described, for example, in U.S. Patent No. 5109095. Preferably, the branched chain vinyl-rich polymer a5) is soluble in resin in xylene at a concentration of >10% by weight, has a D:T range of >10:1, preferably >33:1, and / or (M:Q) = (0.5 to 4):1, respectively, for example. (M 0.7 M * 0.05 Q) 10~500 (1j) It is like this.

[0083] All of these polyorganosiloxanes may be prepared by any conventional method for preparing polydiorganosiloxanes with triorganosiloxane termini. For example, several suitable hydrolyzable silanes in appropriate proportions, such as vinyldimethylchlorosilane, trimethylchlorosilane, tetrachlorosilane, methyltrichlorosilane, and dimethyldichlorosilane, or their corresponding alkoxysilanes, may be co-hydrolyzed and condensed. Alternatively, other reaction pathways may proceed via the equilibration of 1,3-divinyltetraorganodisiloxanes that supply the terminal groups of the polydiorganosiloxane, such as symmetrical divinyldimethyldiphenylsiloxane or divinyltetramethylsiloxane, which may be equilibrated with a suitable polydiorganosiloxane, such as octamethylcyclotetrasiloxane, in the presence of an acid or base catalyst.

[0084] Vinyl-rich polymers are particularly branched-chain polymers having MQ or MDQ structures and Si-alkenyl or SiH groups. These branched-chain polymers can partially or completely replace filler component c) while still providing high mechanical reinforcement. This can be an additional option for reducing viscosity and altering electrical properties.

[0085] In a preferred embodiment, polymer component a2) in the curable silicone composition may be a mixture of polymers of formula (Ia) and / or formula (1d) and / or formula (1j), wherein the mixture preferably has an alkenyl content of less than 2 mol% of all siloxy units of mixture a) on average, and thereby polymer a3) is present in a greater amount than a4) or a5).

[0086] Regarding so-called high-viscosity rubber, the viscosity of the related silicone polymer (rubber) is such that the shear rate D = 10s at 20°C. -1 This is 5-100 kPa·s. In the case of polydimethylsiloxane, this is roughly 3000-12000 siloxy units of P. n Related to the value.

[0087] In preferred embodiments of the curable liquid silicone rubber (LSR) composition, the temperature is 20°C and the shear rate D = 10s. -1 It is preferable to use a viscosity of less than 1 kPa·s; for polydimethylsiloxane, this is approximately <2500 siloxy units P n This relates to the value. In any embodiment, polydimethylsiloxane having vinyl groups is preferred.

[0088] The viscosity of polyorganosiloxane a2) in this embodiment is given by 20°C and shear rate D=10s. -1 Preferably 100 to 300 × 10 3 It is mPa·s and P n The range is from >10 to 2500.

[0089] In preferred embodiments of an LSR composition containing polymer a2) or a mixture of 2 to 4 polymers of component a2), in order to ensure that the liquid silicone rubber composition has a sufficiently low viscosity, the mixture is heated to 20°C and has a shear rate D=10s. -1 The viscosity should be less than 200,000 mPa·s. Such low viscosity is a prerequisite and advantage for producing compositions containing reinforcing fillers and processing such compositions in the LSR injection molding process.

[0090] The alkenyl content of component a2) is, here 1 This can be determined by 1H NMR. See pp. 356 et seq. of Chemical Analysis, edited by JD Winefordner, in AL Smith (ed.): The Analytical Chemistry of Silicones, J. Wiley & Sons 1991 Vol. 112.

[0091] In a further preferred embodiment, component a2) 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) [ka] Each R in the formula is independently selected from saturated organic groups or aromatic organic groups, 1 Each is independently selected from the alkenyl group, and x is ≥ 0.

[0092] A2) At least one polyorganosiloxane of formula (Ib) [ka] x, R and R in the formula 1 This is as defined above; R 3 is R or R 1 Selected from, and y is ≥ 1, and preferably, the alkenyl group R in component a2) 1 Alkenyl group R in component A1) 1 The molar ratio is in the range of 0.3 to 8, preferably 0.6 to 6, and more preferably 1 to 5.

[0093] Component a2) is preferably used to prepare a non-curable masterbatch composition, which also contains a polyorganosiloxane a1) preferably selected from the linear component A1) defined earlier.

[0094] Crosslinking agent component b) In preferred embodiments, the curable polyorganosiloxane composition is cured by a hydrosilylation reaction, in which one or more polyorganohydrogensiloxanes b) are included as crosslinking agents. In such cases, the organic peroxide component e) as a crosslinking initiator is preferably omitted.

[0095] The curable silicone composition of the present invention preferably comprises crosslinking agent component b), which is preferably of the formula RHSiO and R2HSiO 0.5 A polyorganohydrogensiloxane is selected from the group comprising units selected from, wherein the concentration of SiH units is 1 to 100 mol% relative to all siloxane units. In this case, R is an organic group as defined above, and is preferably methyl or phenyl.

[0096] Component b) is preferably at least one polyorganohydrogensiloxane having at least two Si-H groups. A suitable polyorganohydrogensiloxane b) containing SiH units can be formally described by general formula (II), (M 1 a2 D 1 b2 T 1 c2 Q d2 R 2 e2 ) m2 (II) The siloxy unit in the formula is M 1 = M as defined above, or M ** , D 1 = D as defined above, or D ** , T 1 =T as defined above, or T ** , Q is as defined above, and R and R 2This is as defined above, Here M ** =HR2SiO 1 / 2 , D ** =HRSiO 2 / 2 , T ** =HSiO 3 / 2 , a2 = 0.01 to 10, preferably 2 to 5, most preferably 2. b2 = 0 to 1000, preferably = 10 to 500. c2 = 0 to 50, preferably = 0. d2 = 0 to 1, preferably = 0 or 1, most preferably = 0. e2 = 0 to 3, preferably = 0. m2 = 1 to 1000, preferably 1 to 500, most preferably 1 to 20. In this case, it is not possible for all subscripts a through e to be 0, and preferably (a+b) is > 0. However, in general formula (II), M ** , D ** and T ** There are at least two SiH-containing siloxy units selected from the above.

[0097] Preferably, the polyorganohydrogensiloxane b) has at least four, preferably at least five, and more preferably at least six silicon atoms on average.

[0098] Siloxy units may be distributed in a block or random manner within the polymer chain.

[0099] The subscripts mentioned above refer to the number-average molecular weight M, as described above. n Average degree of polymerization P based on n It should represent this.

[0100] The range of M, D, T, and Q units present within the molecule may span almost all values ​​resulting in fluids, fluid polymers, liquid resins, and solid resins. Liquid, linear, cyclic, or branched siloxanes at room temperature (25°C) are preferred. Optionally, these siloxanes may additionally contain trace amounts of C1-C6 alkoxy or Si-hydroxy groups derived from synthesis.

[0101] The preferred structure of component b) in the curable silicone composition of the present invention is a siloxane of formula (2a) to (2e). H a1 (R) 3-a1 Si(RHSiO) x (R2SiO) y (RR 1 SiO) z Si(R) 3-a1 H a1 (2a) More specifically: HR2SiO(R2SiO) y (RR 1 SiO) z (RHSiO) x SiR2H (2b) HMe2SiO(Me2SiO) y (RR 1 SiO) z (MeHSiO) x SiMe2H (2c) Me3SiO(MeHSiO) x SiMe3(2d) {(HRSiO) v (R2SiO) w (2e) Here R and R 1 R is as defined above, and R is preferably methyl and / or phenyl, R 1 is preferably vinyl, and the subscript "a1" is 0 to 1, preferably 0, x = 2 to 1000, preferably = 2 to 500. y = 0 to 650, preferably = 0 to 100. z = 0 to 65, preferably = 0. preferably 3<x+y+z<1000, more preferably 4<x+y+z<650, v is from 2 to 7, w is from 0 to 3, and 3≦v+w≦7.

[0102] Furthermore, resinous polyorganohydrogensiloxanes of the following formula are also possible: {(T 1 )(R 4 O 1 / 2 ) n2} m2 (2f) {(SiO 4 / 2 )(R 4 O 1 / 2 ) n2 (M 1 ) 0,01~10 (T 1 ) 0~50 (D 1 ) 0~1000} m2 (2g) wherein T 1 , M 1 , D 1 are as defined above, n2 is from 0 to 3, m2 is as defined above, R 4 is hydrogen, C1~C 25 alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl, alkanoyl such as acyl, aryl, -N=CHR such as butanone oxime, and alkenyl such as propenyl.

[0103] One preferred embodiment of compound (2g) is, for example, a compound of the formula ((Me2HSiO 0.5 ) k SiO 4 / 2 ) 1~1000These polymer compounds are derived from monomer compounds that may be described as such, where the subscript k is 0.3 to 4. Such liquid or resinous molecules may contain a considerable concentration of OSiOH- groups and / or (C1-C6)alkoxy-Si groups, up to 10 mol% relative to the silicon atom.

[0104] Specific examples of preferred suitable compounds for component b) in the curable silicone composition of the present invention include: Me3SiO-(MeHSiO) 2~650 -SiMe3, (MeHSiO) 4~7 , HMe2SiO-(Me2SiO) 0~300 (MePhSiO) 0~300 (MeHSiO) 1~650 SiMe2H, Me3SiO-(Me2SiO) 0~300 (MePhSiO) 0~300 (MeHSiO) 2~650 SiMe3 Me3SiO-(Me2SiO) 0~300 (Ph2SiO) 0~300 (MeHSiO) 2~650 It is SiMe3.

[0105] Component b) may be used as a single component of a polyorganosiloxane polymer or as a mixture thereof.

[0106] If an increase in curing speed is required, HMe2SiO 0,5 It is preferable to adjust the curing rate and shorten the time by using some polyorganosiloxane b) or MeHSiO-homopolymer having units.

[0107] Component b) is preferably a shear rate D = 10s. -1 It has a viscosity of 2 to 1000 mPa·s at 20°C, as measured by [method / tool ​​name].

[0108] Preferably, crosslinking agent b) should have more than at least 3 reactive SiH groups per molecule. In addition, so-called chain extenders having on average from >1 to 3 reactive SiH groups per molecule may optionally be present.

[0109] For the unsaturated hydrocarbyl residues R that are in component a) in the formulation, and also in b) when b) is present 1 , the molar ratio of the total SiH groups in component b) to the total of said residues is between 0.7 and 15, preferably between 0.8 and 8, more preferably between 1.0 and 7, most preferably between 1.0 and 4.

[0110] Furthermore, it is preferred to use polyorganohydrogensiloxanes in which the molar ratio of R2SiO units to RHSiO units is >1.

[0111] Preferred R groups in this polyorganohydrogensiloxane are methyl, phenyl and 3,3,3-trifluoropropyl. The preferred viscosity at 20°C is less than 1000 mPa·s, more preferably less than 400 mPa·s (measured at a shear rate D=10 -1 -1).

[0112] Component c) Reinforcing filler The curable silicone composition of the present invention may preferably comprise one or more reinforcing filler components, including one or more reinforcing silicas or resins, preferably silicone resins. Preferably, the curable silicone composition comprises one or more, preferably reinforcing, filler components.

[0113] Preferably they are selected from the group of fumed silicas having a BET specific surface area of 50 m 2 / g to 400 m 2 / g.

[0114] Fumed silica, where appropriate, is surface-modified reinforcing filler c). Reinforcing filler c) has a specific surface area of 50 m 2Characterized by a BET specific surface area of ​​ / g or greater and a primary particle diameter of <50 nm. In the context of the present invention, component d) is not composed of the reinforcing filler c).

[0115] Preferably, the surfaces of these fillers are hydrophobic. When component c) is used, the amount is preferably up to 100 parts by weight, preferably 0 to 60 parts by weight, more preferably 0 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, relative to 100 parts by weight of component a) i.e., polyorganosiloxane a2).

[0116] 50m 2 Fillers with a BET specific surface area exceeding 200m² / g enable the production of silicone elastomers with improved mechanical properties. Fumed silica is preferred in terms of strength, electrical resistance and flame retardancy, and even more preferred silica is supplied by, for example, Evonik (formerly Degussa), Wacker, or Cabot, among others. 2 Aerosil® 200, 300, 400, HDK® N20 or T30, Cab-O-Sil® MS7 or HS5, having a BET specific surface area greater than / g.

[0117] The filler c) may have undergone any suitable conventional surface treatment, and a suitable surface treatment agent is a reactive silane or siloxane as an auxiliary additive f). Preferred silanes or siloxanes for surface treatment are preferably silazanes such as hexamethyldisilazane and / or 1,3-divinyltetramethyldisilazane in the presence of water, and in a preferred embodiment, the surface treatment may be carried out by hydrophobizing the filler surface "in situ". In other embodiments, the surface treatment may also be carried out with other known filler treatment agents, such as polyorgano-siloxanediols supporting unsaturated organic groups with chain lengths of 2 to 50.

[0118] The filler treatment agent may provide reaction sites for the crosslinking reaction.

[0119] In preferred embodiments of the curable liquid silicone rubber, treatment with hexaorganodisilazane and water, and the reaction product thereof, are preferred.

[0120] Examples of commercially available silica pre-hydrophobized with various silanes include: Aerosil R972, R974, R976, or R812, or, for example, HDK2000 or H30. The rheological properties, i.e., the technical processing properties, of the uncured silicone rubber mixture may be influenced by the choice of filler type, amount, and hydrophobicity.

[0121] For example, if the particle size is less than 100 μm and less than <50 μm 2 Other fillers, such as semi-reinforced or unreinforced fillers, including all particulate fillers with a BET specific surface area of ​​1 / g, are counted under component f) as auxiliary additives.

[0122] Component d) One or more carbon black The curable silicone composition according to the present invention contains one or more carbon blacks d), which are preferably incorporated into the curable silicone composition of the present invention by mixing other components of the curable composition with a non-curable composition, i.e., a carbon black masterbatch.

[0123] The amount of one or more carbon blacks d) in the curable silicone composition of the present invention is 0.1 to 2 parts by weight per 100 parts of polyorganosiloxane a2) having one or more unsaturated groups.

[0124] More preferably, the amount of one or more carbon blacks d) in the curable silicone composition of the present invention may be, for example, about 0.15 to 2 parts by weight, more preferably 0.2 to 1.5 parts by weight, and even more preferably 0.3 to 1 part by weight, per 100 parts of polyorganosiloxane a2) having one or more unsaturated groups.

[0125] Preferably, the curable composition of the present invention contains only one type of carbon black.

[0126] Preferably, the curable silicone composition according to the present invention contains one or more carbon black d) in about 0.1% to about 2.4% by weight, preferably about 0.3% to about 2.2% by weight, and more preferably about 0.5% to about 2.0% by weight, based on the total weight of the curable silicone composition.

[0127] Essentially, all types of carbon black may be used as carbon black d) (such as acetylene black, channel black, furnace black, lamp black, or thermal black). As is well known to those skilled in the art, carbon black is a form of quasicrystalline carbon and generally has a high surface area-to-volume ratio, although lower than that of activated carbon. Carbon black is dissimilar to soot in that it has a much larger surface area-to-volume ratio and a remarkably low (very small and unbiologically unusable) polycyclic aromatic hydrocarbon (PAH) content.

[0128] In a preferred embodiment of the present invention, at least one insulating compound d) is conductive carbon black, preferably furnace carbon black, i.e., produced by a furnace black process.

[0129] In a preferred embodiment, one or more carbon blacks d) >30m 2 BET specific surface area per g, and / or average primary particle diameter D from 5 nm to 500 nm. 50 It contains at least one carbon black selected from conductive carbon blacks having [specific properties].

[0130] In a more preferred embodiment, one or more carbon blacks include at least one carbon black selected from conductive carbon blacks having one or more of the following properties: >100m2 / g to 1500 m 2 / g, more preferably >100 m 2 / g to 1400 m 2 / g, more preferably >100 m 2 / g to 1000 m 2 / g, more preferably >250 m 2 / g to 1000 m 2 / g, more preferably >500 m 2 / g to 1000 m 2 / g BET specific surface area, and / or • a primary particle diameter D of 5 nm to 500 nm, more preferably 10 nm to 200 nm 50 , and / or • a DBP pore volume of 300~600 ml / 100 g, more preferably 300~550 ml / 100 g, still more preferably 300~400 ml / 100 g, and / or • an iodine adsorption amount of 700~1200 mg / g, more preferably 700~1150 mg / g, still more preferably 700~1000 mg / g, even more preferably 700~900 mg / g, and / or • a pH of 8~11, more preferably a pH of 9~11, still more preferably a pH of 9~10.5, and / or • a metal content of <50 ppm, and / or • a sulfur content of <150 ppm, and / or • a moisture content of <0.5 wt%, and / or • a volatile component content of <1 wt%, and / or • fine particles of <125 micrometers in pellets account for <10 wt%, and / or • a grit content of <50 mg / kg, and / or • an ash content of <0.1 wt%.

[0131] Preferably, only one type of carbon black is contained in the curable silicone composition according to the present invention.

[0132] Commercially available carbon blacks include PrintexXE2, PrintexHV (Evonik), Black Pearls2000, VulcanoxC72, VulcanoxC72 (Cabot), Ketjen Black EC300J, Ketjen Black EC600JD (AkzoNobel), Ensaco 360g, Ensaco 350g, Ensaco 350p, Ensaco 250g (Timcal), CL-08 (Continental Carbon), Denka Black HS100, Denka Black HS100, Denka Black HS100 (Denka Chemicals), CD7087 (Colombian Chemicals), TokaBlack5500 (Tokai Carbon), Chezacarb A (Unipetrol), and others.

[0133] Particularly preferred carbon blacks are conductive carbon black sold under the trademark Ketjenblack (AkzoNobel), especially Ketjenblack EC-300J, and electrically conductive carbon black in pellet form (CAS number 1333-86-4).

[0134] Component d1) Belongs to another insulating compound (auxiliary additive f) The curable silicone composition according to the present invention may optionally contain, in addition to one or more carbon blacks d), other (one or more) insulating compounds d1) as auxiliary additives f), which are selected from the group consisting of conductive or semiconducting fillers.

[0135] Such other insulating compounds d1) are preferably selected from the group of conductive or semiconducting fillers, including, for example, graphite, graphene, fullerene, carbon nanotubes, oxides, carbides, ferrites or spinels of Ti, Al, Zn, Fe, Mn, Mo, Ag, Bi, Zr, Ta, B, Sr, Ba, Ca, Mg, Na, K, and Si, as well as their inorganic salts such as chlorides and sulfides, and also selected from the group of ionic liquids and ionic polymers.

[0136] The amount of such other insulating compounds can be, for example, about 0 to 2 parts by weight, preferably 0.1 to 2 parts by weight, more preferably >0.15 to 2 parts by weight, more preferably >0.2 to 1.5 parts by weight, and even more preferably >0.3 to 1 part by weight, per 100 parts by weight of polyorganosiloxane a2) having one or more unsaturated groups.

[0137] The particulate insulating compound preferably has an average diameter D of 5 nm to 500 nm, preferably 5 nm to 200 nm. 50 It holds.

[0138] D 50 This is measured by light scattering according to ISO 22412:2008. In particular, for pellet materials, particle size sieving analysis should show that particles with a diameter exceeding 125 μm should be less than 10% by weight.

[0139] Other suitable components as component d1) are ionic liquids and ionic polymers, which are selected from the group consisting of compounds containing ammonium groups, phosphonium groups, carboxyl groups, phosphate groups or sulfonate groups, and counterions such as cations or anions.

[0140] Other preferred insulating active components d1) are selected from the group consisting of titanium dioxide (TiO2), iron and zinc, and oxides, particularly spinel and ferrite. In preferred embodiments, however, the use of ZnO is undesirable.

[0141] A preferred titanium dioxide as the insulating active component d1) has a BET specific surface area in the range of 35 to 300 m². 2 It has a particle size of less than 30 nm and a number mean primary particle size of 21 nm. For example, P25 (De Gussa-Evonik), which is fumed TiO2, has a number mean primary particle size of 21 nm and a particle size of 50 nm. 2 It has a BET specific surface area of ​​1 / g. Another type of TiO2 is the precipitated anatase type (Kronos 7050), for example, about 225m 2 It has a BET specific surface area of ​​15 nm and a number-average primary particle diameter / crystal dimension of 15 nm.

[0142] The use of TiO2 or Fe3O4 as component d1) is also useful to enhance the flame retardant effect achieved by the curing catalyst based on the Pt compound as component e).

[0143] In preferred embodiments of the present invention, the curable silicone composition contains only one or more carbon blacks d) as the insulating active compound.

[0144] However, if any insulating active compound d1) other than carbon black d) is present in the curable silicone composition according to the present invention, the amount thereof can be 0.01 wt% to 1.96 wt%, preferably 0.05 wt% to 1.90 wt%, more preferably 0.1 wt% to 1.8 wt%, more preferably 0.15 wt% to 1.7 wt%, more preferably 0.2 wt% to 1.5 wt%, more preferably 0.3 wt% to 1.0 wt%, and more preferably 0.3 wt% to 0.7 wt% with respect to the total weight of the curable silicone composition.

[0145] According to the present invention, the amount and type of insulating active compounds d) (one or more carbon blacks) and d1) (insulating active compounds other than carbon black), preferably the amount of d) alone, are appropriately adjusted so that the cured silicone composition has electrical properties that make it suitable as an insulator, particularly for high voltage direct current (HVDC) applications, in particular, in an electric field of 10kV / mm to 30kV / mm in the range of 25°C to 90°C, with an electrical conductivity of 1 × 10⁻¹⁰ 11 A value greater than Ωcm, preferably 1 × 10⁻⁶ 12 Greater than Ωcm, more preferably 1 × 10⁻⁶ 13 Greater than Ωcm, and even more preferably 1 × 10⁻⁶ 14 Greater than Ωcm, and preferably up to 1 × 10⁻⁶ 16The volume resistivity is made to be Ωcm. Furthermore, according to the present invention, the amount and type of insulating active compounds d) and d1) (preferably d) only) are adjusted as appropriate so that the cured silicone composition of the present invention has a temperature-dependent volume resistivity in an electric field of 10kV / mm to 30kV / mm in the range of 25°C to 90°C, and the ratio of the maximum volume resistivity to the minimum volume resistivity is <10, and / or the volume resistivity is preferably 1 × 10 in an electric field of 10kV / mm to 30kV / mm in the range of 25°C to 90°C. 11 Greater than Ωcm, more preferably 1 × 10⁻⁶ 13 Greater than Ωcm, more preferably 1 × 10⁻⁶ 16 Greater than Ωcm, and even more preferably 1 × 10⁻⁶ 17 A value greater than Ωcm, preferably 1 × 10⁻⁶ 18 The hardening ratio is reduced to Ωcm. Furthermore, the curing silicone composition of the present invention is preferably 1 × 10 in an electric field of 10 kV / mm to 30 kV / mm in the range of 25°C to 90°C. 11 From 1 x 10 18 Between Ωcm, preferably 1 × 10 13 From 1 x 10 18 Between Ωcm, more preferably 1 × 10 14 From 1 x 10 18 Between Ωcm, and most preferably 1 × 10 16 From 1 x 10 18 It has a volume resistivity between Ωcm. Most preferably, the carbon black content is 1.0% to 2.0% by weight of one or more carbon blacks d) based on the total weight of the curable composition, and the volume resistivity is 1 × 10 in an electric field of 10kV / mm to 30kV / mm in the range of 25°C to 90°C. 16 From 1 x 10 18 This is a curable silicone composition located between Ωcm and Ω.

[0146] The volume resistivity of the cured silicone composition is measured according to DIN EN62631-3-1 using a test sheet with an effective diameter of 31 mm and a thickness of 1 mm.

[0147] Measurements were performed at room temperature unless otherwise specified. Electrodes were made of brass and polished before use. Conductive coatings (e.g., silver ink) were not used because the silicone made sufficient contact with the electrodes. For polarization, a Heinsinger PNChp-30000-2 type DC source was used with a maximum voltage of 30 kV / mm and a maximum current of 2 mA. The minimum detectable current was 1 fA (femtoampere). The highest resolution in this test setup was achieved at 10 fA.

[0148] Process for incorporating the above-described non-curable silicone composition (masterbatch) into a curable silicone composition according to the present invention. The carbon black component d) is appropriately incorporated into the curable silicone composition of the present invention, in the form of the non-curable silicone composition according to the present invention, i.e., as a masterbatch, for example, using a dissolver mixer.

[0149] Generally, the hydrosilylated / addition-cured silicone composition according to the present invention is prepared by manufacturing a two-component system, one of which comprises a polyorganosiloxane a2) and a carbon black masterbatch (i.e., the non-curable silicone composition according to the present invention), an optional filler component c), a hydrosilylation catalyst e), and an optional auxiliary additive f), while the other comprises a polyorganohydrogensiloxane b), an optional filler component c), and an optional auxiliary additive f). For curing, both components are mixed and then heated to obtain the cured silicone composition according to the present invention.

[0150] Component e) Curing catalyst In one preferred embodiment, the curing catalyst is selected from the group consisting of compounds that enable curing by hydrosilylation reaction, in an amount of 0 to 1000 ppm (relative to the total weight of components a to d).

[0151] The curing catalyst e) used as a hydrosilylation catalyst in the present invention is selected from the group consisting of metals or metal compounds of Pt, Pd, Rh, Co, Ni, Ir, or Ru.

[0152] The curable silicone composition of the present invention contains component b) a SiH-polyorganosiloxane, and optionally, if necessary for flame retardancy, contains platinum or at least one platinum compound e) which preferably acts as a curing catalyst.

[0153] Possible Pt component e) may be selected from, for example, ordinary platinum catalyst components, and may be selected with or without a support such as activated carbon, carbon, or silica powder, from the group of organoplatinum compounds, platinum metals, or salts, as taught in, for example, U.S. Patent Nos. 3,159,601; 3,159,662; 3,419,593; 3,715,334; 3,775,452 and 3,814,730.

[0154] The hardening reaction may be initiated not only by hydrosilylation, but also by other metals or metal compounds known to those skilled in the art. These other metals may include Pd, Rh, Co, Ni, Ir, or Ru.

[0155] A suitable platinum compound also includes a photoactivating catalyst, which is a (h-diolefin)-(σ-aryl)-platinum complex (e.g., U.S. Patent No. 4,530,879 or U.S. Patent Publication No. 2003 / 0199603), h 5The invention includes cyclopentadienyl platinum complex compounds or complexes with sigma-bonded ligands, preferably optionally substituted cyclopentadienyl ligands having sigma-bonded alkyl or aryl ligands. Other platinum compounds may also be used in principle, by using azodicarboxylic acid esters, as disclosed in U.S. Patent No. 4,640,939, or by controlling their activity with diketonates. The photoactivatable platinum compounds that may be used are further selected from the group having ligands selected from diketones. Other Pt catalysts are mentioned, for example, in U.S. Patent No. 3,715,334 or U.S. Patent No. 3,419,593, European Patent Publication No. 1672031A1 and Organometallics 1995, No. 14, pp. 2202-2213 by Lewis, Colborn, Grade, Bryant, Sumpter and Scott, all of which are incorporated into the invention by reference.

[0156] Component e), when used for the hydrosilylation reaction of the curable silicone composition of the present invention, acts as a catalytic compound, catalyzing the reaction between the hydrogen atom bonded to the silicon of component b) and the olefinic hydrocarbon substituent bonded to the silicon of component a). The metal or organometallic compound may be any catalytically active metal, and is generally a platinum group metal containing a catalytically active component. Preferably, the metal of component e) is any platinum complex compound.

[0157] A typical platinum-containing catalyst component in the curable polyorganosiloxane composition of the present invention is any form of platinum(0), (II), or (IV) compound capable of forming a complex with phosphorous acid. Preferred complexes are Pt(0) alkenyl complexes such as alkenyls, cycloalkenyls, and alkenylsiloxanes like vinylsiloxanes, from the viewpoint of ease of dispersibility in the polyorganosiloxane composition.

[0158] Particularly useful forms of platinum complexes include Pt(0) complexes with aliphatic unsaturated organosilicon compounds, such as 1,3-divinyl-tetramethyldisiloxane (vinyl-M2 or Karstedt catalyst) disclosed in U.S. Patent No. 3,419,593, incorporated herein by reference, and also cyclohexane-Pt, cyclooctadiene-Pt, and tetravinyl-tetramethyl-tetracyclosiloxane (vinyl-D4). These catalysts exhibit the best dispersibility in the curable silicone compositions of the present invention.

[0159] Pt(0) olefin complexes include, for example, 1,3-divinyl--tetramethyldisiloxane (M Vi It is prepared by reduction of hexachloroplatinic acid or other platinum chlorides with an alcohol in the presence of a basic compound such as an alkali carbonate or hydroxide (hydrazine reduction products of Pt(IV) and Pt(II) can also be used).

[0160] The amount of platinum-containing catalyst component used as a flame retardant additive in the curable silicone composition of the present invention is limited by two constraints.

[0161] On the one hand, the quantity must provide the desired combustion resistance, and on the other hand, for cost reasons, the quantity must be as small as possible, thus balancing reactivity with pot life during storage.

[0162] Therefore, it is preferable to provide a curable polyorganosiloxane composition in which the platinum concentration is between 1 and 120 ppm, preferably 1 to 100 ppm, more preferably 1 to 70 ppm, and even more preferably 1 to 38 ppm (based on the metal related to components a) to f).

[0163] In general, the reactivity of Pt catalysts must be controlled with respect to the curing time by so-called inhibitors specified as auxiliary additives under component f).

[0164] In another embodiment of the present invention, the curing catalyst e) is selected from the group of organic peroxides relating to a) to f) in an amount of 0.1% to 2% by weight, in which case such organic peroxide is selected from the group consisting of substituted or unsubstituted dialkyl peroxides, alkylaloyl peroxides, and dialoyl peroxides.

[0165] Suitable peroxides are those commonly used in high-viscosity silicone rubbers (HCR, HV, HTV) and are selected from the group consisting of dialkyl peroxides, alkylaloyl peroxides, and dialoyl peroxides. Preferred peroxides are any peroxides having a half-life that allows a mixture of the curable polyorganosiloxane composition of the present invention containing the peroxide to be stored at 25°C for at least 10 days, preferably more than 30 days, without scorching. Scorching refers to either premature curing, i.e., an increase in Mooney viscosity beyond 20 Mooney units, or gelation, i.e., an increase in the loss modulus G'' measured on a rheometer to the level of the elastic modulus G'.

[0166] A preferred reactivity for peroxides is one in which curing of polymethylsiloxane or polymethylvinylsiloxane occurs in less than 15 minutes at a temperature below 180°C.

[0167] Preferred examples of such curing agents are organic peroxides such as bis-benzoyl peroxide, bis-o-methylbenzoyl peroxide or p-methylbenzoyl peroxide, bis-2,3-dichlorobenzoyl peroxide, bis-2,4-dichlorobenzoyl peroxide or bis-2,5-dichlorobenzoyl peroxide, and ditertically butyl peroxide, which are preferably used in atmospheric pressure hot air vulcanization. Other examples of peroxides include butyl peroxybenzoate, dicumyl peroxide, α,α'-di(t-butylperoxy)diisopropylbenzene, and 2,5-bis-(t-butylperoxy)-2,5-dimethylhexane, which are used in transfer molding or injection molding under pressurized conditions.

[0168] The HCR silicone composition can also be cured with component b) and a hydrosilylation catalyst. From the viewpoint of flame retardancy, it is preferable to use the Pt hydrosilylation catalyst not only as a crosslinking catalyst but also as a dual-purpose additive to improve flame retardancy.

[0169] Component f) Auxiliary additives The curable silicone composition according to the present invention may optionally contain auxiliary additives f), which are preferably selected from the group consisting of pigments, adhesion promoters, plasticizers, flame retardant additives, solvents, diluents, process aids for filler treatment, and other insulating compounds d1) described above.

[0170] Adhesion promoter A curable silicone composition according to one embodiment of the present invention comprises at least one adhesion promoter. These compounds improve the performance of the composition of the present invention in adhering to several substrate surfaces, such as metals, thermoplastic or thermosetting plastic surfaces, glass, natural or synthetic fabric fibers, and other ceramic substrates.

[0171] The adhesion promoter is preferably used in an amount of 0.1% to 2% by weight relative to component a). Some of the crosslinking agents b) may act as adhesion promoters if they have substituents other than SiH units, such as aryl groups, acrylic groups, methacrylic groups, or epoxy groups. Some of the nitrogen compounds f) may also act as adhesion promoters, especially if they contain alkoxysilyl groups.

[0172] One preferred example of an adhesion promoter is selected from the group consisting of silanes of formula (3): X-(CR 9 2) e -Y-(CH2) e SiR 9 d (OR 8 ) 3-d (3) During the ceremony X is selected from the group consisting of halogen groups, pseudohalogen groups, unsaturated aliphatic groups with up to 14 carbon atoms, epoxy group-containing aliphatic groups with up to 14 carbon atoms, cyanurate-containing groups, and isocyanurate-containing groups. Y is selected from the group consisting of a single bond and a heteroatom group selected from -COO-, -O-, -S-, -CONH-, and -HN-CO-NH-. R 9 R is selected from hydrogen, and R is as defined above. R 8 is a C1-C8 alkyl group, and e is 0, 1 to 8, and can be the same or different. d is between 0, 1 and 2.

[0173] Preferred examples of adhesion promoter f) include: gamma-glycidyloxypropyl trialkoxysilane, (3,4-epoxycyclohexyl)alkyl trialkoxysilane, methacryloxypropyl trialkoxysilane, isocyanate-propyl trialkoxysilane, isocyanate-methyl trialkoxysilane, and vinyl trialkoxysilane.

[0174] Other optional auxiliary additives are used in amounts of 0 to 15 parts by weight per 100 parts by weight of component a). Auxiliary or conventional additives include, for example, plasticizers, release oils, and hydrophobic oils, and are preferably polydimethylsiloxane oil, polydiphenyldimethylsiloxane oil, etc., having a viscosity of 0.001 to 10 Pa·s at 20°C.

[0175] Furthermore, especially when present as an outer layer, it is desirable that the layer be colored with a minimum amount of inorganic or organic pigment, as such pigments often degrade or damage the mechanical or electrical properties. Additionally, release agents or flow improvers may be used, examples of which are fatty acid derivatives or aliphatic alcohol derivatives, or fluorinated alkyl surfactants. Compounds advantageously used in the present invention are those that rapidly separate and migrate to the surface. Stability after exposure to hot air may be increased by using known hot air stabilizers, such as Fe compounds, Mn compounds, Ti compounds, Ce compounds, or La compounds, and organic salts, preferably organic complexes such as their diketonates or triketonates.

[0176] Furthermore, the auxiliary additive f) may include a hydrophobic agent for the treatment of the filler component c), such as an organic silanol or organic silazane, and water, such as trimethylsilanol, vinyldimethylsilanol, hexamethyldisilazane, or 1,3-divinyltetramethyldisilazane.

[0177] Auxiliary additives may also include so-called inhibitors to control the hydrosilylation crosslinking reaction. When the curable silicone composition contains all the components for the hydrosilylation reaction, namely the alkenyl group of a1), the SiH group of b), and platinum or a compound thereof, the reaction rate should preferably be controlled by an inhibitor to avoid premature curing of the curable silicone composition at 25°C prior to the desired curing or molding process for the production of coatings or molded articles. Inhibitors useful for the hydrosilylation reaction are well known. Examples of advantageous inhibitors include, for example, vinyl siloxane, 1,3-divinyltetramethyldisiloxane, or tetravinyltetramethyl-tetracyclosiloxane. Other known inhibitors that interact with the above-mentioned Pt compounds can be used, for example, alquinols such as ethynylcyclohexanol and 3-methylbutynol, dimethyl maleates, alkylphosphines, arylphosphines or alkylarylphosphines, alkylphosphites, arylphosphites or alkylarylphosphites, or alkylamines or arylamines, thereby affecting the hydrosilylation activity of the catalyst and providing an excellent balance between storage stability and high-temperature reactivity during curing.

[0178] To increase flame retardancy, it is preferable to use nitrogen-based or phosphorus-based compounds that can enhance the effect of Pt compounds. These flame retardant additives are selected from the group consisting of azo, hydrazo, triazole, tetrazole, guanidine, melamine, urea, or phosphite derivatives.

[0179] Solvents and / or diluents A curable silicone composition of a particular embodiment of the present invention is suitable for spray applications. In such cases, the curable silicone composition of the present invention may contain a solvent and / or diluent. Such solvents and / or diluents can be selected from organic solvents such as siloxanes, hydrocarbon solvents, ester solvents, and alcohol solvents.

[0180] Other bulking fillers or pigments Auxiliary additives may also contain other bulking fillers. Such other fillers are different from insulating compounds d) or d1). Their use should not impair the effect of component d) or d1). Additional pigments or bulking fillers should be incorporated insofar as they do not interact with, damage, or halt the dielectric properties of component d) or d1).

[0181] Therefore, the bulking filler or pigment can be used solely to have an effect very similar to or to interact with component d). When used, the concentration should therefore be less than 1% by weight, preferably less than 0.1% by weight.

[0182] Typical organic pigments are selected from groups such as perylene-based organic pigments and phthalocyanine-based organic pigments.

[0183] The bulk filler can be selected from the group of silicates, diatomaceous earth, pulverized silica, quartz, mica, amorphous carbonates, borates, hydroxides / oxides, and oxides of Al, Ca, Mg, Fe, and Zn, having a particle size larger than that of component d). These abrasive fillers and pigments are preferably particle sizes from 1 to 100 μm and <30 m 2 It is a semi-reinforced or unreinforced filler or pigment having a BET specific surface area of ​​1 / g.

[0184] In addition, since many of these fillers are very often abrasive to the nozzles, surfaces, or molds of injection molding machines or mixers, most of these fillers are omitted for several other reasons. It is part of the concept of this invention that the concentration of abrasive fillers should be kept as low as possible in order to increase the lifespan of the injection molding machine nozzles and the molds themselves. Such abrasive fillers may be acceptable if they are not abrasive to the metal surface of the nozzle in the injection molding process, but in principle these fillers should be avoided or should be less than 3 parts by weight per 100 parts by weight of component a). Abrasive fillers such as crushed quartz or cristobalite powder or diatomaceous earth are generally less desirable.

[0185] All curable silicone compositions of the present invention are curable by any of the relevant processes for manufacturing the molded articles formed, including processes known in silicone technology and coatings obtained by spray coating the curable silicone compositions of the present invention. The cured material of the curable silicone compositions of the present invention is an elastomer and is preferably used in the manufacture of insulators for high-voltage DC applications. Preferably, the curable silicone compositions of the present invention are formed and cured before the cable joint or termination is assembled to the cable, but generally the curing step can be performed at any point in the process flow of assembling the cable accessory, i.e., curing and molding do not need to be performed simultaneously.

[0186] The present invention also relates to a method for producing an insulator useful for application in high-voltage applications, wherein the curable silicone composition of the present invention is formed by extrusion through a nozzle or by a mold, and the formed composition is cured by heat or light to form a formed insulator. These processes are optionally carried out in the presence of at least one other silicone material different from the curable silicone composition of the present invention. Such other different materials may be silicone, rubber or thermoplastic materials that differ at least in the physical properties and ratios and / or concentrations of individual components a) to f).

[0187] The cured curable silicone composition of the present invention can be used as an insulating material on its own, but is preferably used in combination with other well-known materials in the design of HVDC cable accessories. For example, cable joints or cable terminations are very often multilayered in design, and thereon they contain at least one material that provides high conductivity, e.g., 1 × 10⁻¹⁶ 4 Conductive EPDM, conductive silicone rubber, or conductive thermoplastic resin having a volume resistivity of less than Ωcm is used as a shielding material for part of the joint. Some parts of such cable accessories may take the form of a tube or tubular trumpet and can therefore be manufactured by an extrusion process.

[0188] The final insulator very often requires a more complex assembly of two to four different materials and is therefore manufactured by the assembly of extruded and molded parts, and in some cases the final outer layer is applied as a coating material by injecting low-viscosity silicone rubber with the assistance of an open mold cavity, which is optional, especially for large-volume joints.

[0189] The curable silicone composition of the present invention is preferably used as a cured composition for high-voltage DC applications, and more preferably for the manufacture of cable joints, boots, sleeves, fittings and other cable accessories and cable terminations.

[0190] The cured silicone composition of the present invention is particularly used for the manufacture of a cable joint intended to seal the cable ends of one or more cables having thermoplastic polyolefin or rubber cable insulation, where the cable joint seals the cable ends of one or more cables having thermoplastic polyolefin or rubber cable insulation.

[0191] The present invention also relates to a method for manufacturing a cable joint, comprising the steps of: A1) providing a silicone composition in which at least one conductive form is optionally cured, unlike the silicone composition according to the present invention; and B1) coating the composition from step A1) with the silicone composition according to the present invention in a mold, and molding and curing it into a cable joint or cable end.

[0192] Furthermore, the present invention relates to a method for sealing and / or insulating connected cables or closing cable ends by using the cable joint specified above, which j) A step of providing an insulated wire having a multilayer coating of thermoplastic or elastomer suitable for DC insulation, and a bare wire or connector portion. jj) The process includes mechanically expanding the joint such that an overlap of more than approximately 0.5 cm is achieved between the molded silicone cable joint and the sheath on the insulating wire, thereby covering the bare wire or connector by positioning the hole of the pre-molded and cured tubular cable joint as defined above over the surface of the insulating sheath of j), thereby sealing the insulating sheath of the insulating wire by the mechanical pressure of the released joint, and forming a covered insulator that is also for bare wires and connectors.

[0193] This assembly process, namely the sealing process of one or more insulated cables, can be carried out by expanding the cable joint or cable termination by expanding a tubular hole with the assistance of compressed air or a stent-like plastic or metal tool, or by means of holding the joint in an enlarged shape, and then releasing it under heating like a shrinking tube.

[0194] Another process according to the present invention involves optionally using a transparent form, applying all materials in-situ after covering a cable or multiple cables, and initiating curing at a temperature between 0°C and 200°C or with the assistance of light and a photo-activated curing catalyst e).

[0195] The cured silicone composition according to the present invention has unique electrical properties compared to conventional cured silicone compositions prepared using a non-extruded carbon black masterbatch.

[0196] In a further embodiment, the present invention relates to a curable silicone composition, which is: a) 100 parts by weight of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2) b) A crosslinking agent component comprising 0 to 100 parts by weight, preferably >0 to 100 parts by weight, one or more polyorganohydrogensiloxanes. c) 0 to 100 parts by weight, preferably >0 to 100 parts by weight, of one or more filler components comprising one or more reinforcing silica or resin. d) More than 2 parts by weight, preferably 4 to 12 parts by weight of carbon black, e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) Contains one or more auxiliary additives in 0 to 50 parts by weight.

[0197] Such curable silicone compositions preferably contain more than 2.4% by weight, preferably 3% to 10% by weight, of one or more carbon blacks d) based on the total weight of the curable silicone composition.

[0198] These high-carbon-black curable compositions can typically be cured into electrically and thermally conductive silicone compositions and can be used in applications requiring electrically and / or thermally conductive silicone rubber, such as the manufacture of connectors, electrically conductive films, electrode materials, and heat dissipation materials. [Brief explanation of the drawing]

[0199]

[0200] Preferred Embodiments of the Invention Preferred embodiments of the present invention are described below.

[0201] 1. A process for producing a non-curing silicone composition containing carbon black, comprising extruding one or more polyorganosiloxanes a1) together with one or more carbon blacks d).

[0202] 2. The total viscosity of one or more polyorganosiloxanes (a1) is less than 100 Pa·s, preferably between 1 and 100 Pa·s (D=10s at 20°C). -1 The process according to the above embodiment, which is measured at the shear rate.

[0203] 3. A process according to any of the preceding embodiments, wherein polyorganosiloxane a1) is selected from polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups.

[0204] 4. Polyorganosiloxane a1) has an organic substituent R selected from the group consisting of optionally substituted alkyl groups such as alkyl groups and halogen alkyl groups, and optionally substituted aryl groups such as phenyl groups, and one or more substituent R selected from the group consisting of alkenyl groups such as vinyl groups. 1 A process according to any of the above embodiments, having the following characteristics.

[0205] 5. A process according to any of the preceding embodiments, wherein the extrusion is carried out by an extruder such as a multi-screw extruder, preferably a twin-screw extruder, more preferably a twin-screw extruder with simultaneous rotation.

[0206] 6. A process according to any of the preceding embodiments, wherein the extrusion is carried out at a temperature in the range of room temperature (25°C) to 250°C, preferably 50°C to 200°C, and more preferably 100°C to 175°C.

[0207] 7. A process according to any of the preceding embodiments, in which extrusion is performed using one or more of the following conditions: • Two-screw system rotating simultaneously, • Screw diameter in the range of 15mm to 250mm, preferably 20mm to 100mm. • A supply speed of approximately 1 kg / hour to 600 kg / hour, preferably 100 kg / hour to 550 kg / hour, more preferably 10 kg / hour to 50 kg / hour. Screw speed of 50 rpm to 1200 rpm, preferably 100 rpm to 1000 rpm. • Extrusion temperature from 50°C to 200°C L / D ratio of 20 to 80, preferably 30 to 70, (where L is the length of the extruder and D is its diameter) • Residence time of 10 seconds to 10 minutes, preferably 15 seconds to 2 minutes. • Use of cylinder cooling, • Segmented design with a geometric shape that allows for powerful dispersion of the screw element.

[0208] 8. A process according to any of the preceding embodiments, wherein the weight ratio of one or more polyorganosiloxane a) to one or more carbon black d) is 90:10 to 75:25, preferably 89:11 to 80:20.

[0209] 9. A process according to any of the preceding embodiments, in which only one or more polyorganosiloxanes a) and one or more carbon blacks d) are extruded.

[0210] 10. A non-curing silicone composition obtained by a process defined by any of the preceding embodiments.

[0211] 11. A non-curing silicone composition according to any of the preceding embodiments, comprising at least 10% by weight, preferably at least 11% by weight, and more preferably at least 12% by weight, one or more carbon blacks d) based on the total weight of the entire silicone composition.

[0212] 12. A non-curing silicone composition according to any of the preceding embodiments, comprising 10 to 25 weight percent, preferably 11 to 24 weight percent, and more preferably 12 to 23 weight percent, of one or more carbon blacks d) based on the total weight of the entire silicone composition.

[0213] 13. A non-curing silicone composition according to any of the preceding embodiments, comprising one or more polyorganosiloxanes a1) and one or more carbon blacks d).

[0214] 14. One or more carbon blacks > 30m 2 A non-curable silicone composition according to any of the previous embodiments, comprising at least one selected carbon black having a BET specific surface area of ​​ / g and / or D50 having an average primary particle diameter between 5 nm and 500 nm.

[0215] 15. A non-curing silicone composition according to any of the preceding embodiments, comprising at least one carbon black selected from conductive carbon blacks having one or more of the following properties: >100m 2 / g to 1500m 2 / g, comfortable > 100m 2 / g to 1400m 2 / g, comfortable > 100m 2 / g to 1000m 2 / g, comfortable > 250m 2 / g to 1000m 2 / g, comfortable > 500m 2 / g to 1000m 2 BET specific surface area / g, and / or ·D 50 Particle size between 5 nm and 500 nm, more preferably 10 nm and 200 nm, and / or DBP pore volume of 300-600 ml / 100g, more preferably 300-550 ml / 100g, more preferably 300-400 ml / 100g, and / or Iodine adsorption amounts of 700-1200 mg / g, more preferably 700-1150 mg / g, more preferably 700-1000 mg / g, more preferably 700-900 mg / g, and / or pH 8-11, more preferably pH 9-11, more preferably pH 9-10.5 and / or • Metal content <50 ppm, and / or • Sulfur content <150 ppm, and / or • Moisture content <0.5% by weight, and / or • Volatile component content <1% by weight, and / or • The pellet contains <10% by weight of fine particles <125 micrometers, and / or • Grit content <50 mg / kg, and / or • Ash content <0.1% by weight.

[0216] 16. A non-curable silicone composition according to any of the previous embodiments, wherein, as determined by dynamic light scattering, the proportion of particles smaller than 10 μm is greater than 70%, preferably greater than 80%, more preferably greater than 90%, and / or the proportion of particles larger than 10 μm is less than 30%, preferably less than 20%, more preferably less than 10%, and more preferably less than 5%.

[0217] 17. A non-curable silicone composition according to any of the preceding embodiments, wherein the Dn50 of the particle size distribution based on the number of particles of the non-curable silicone composition is preferably less than 7 μm, more preferably less than 5 μm, and most preferably less than 3 μm.

[0218] 18. A non-curable silicone composition according to any of the preceding embodiments, wherein the Dn90 of the particle size distribution based on the number of particles of the non-curable silicone composition is preferably less than 15 μm, more preferably less than 10 μm, more preferably less than 8 μm, and most preferably less than 5 μm.

[0219] 19. Use of a non-curable silicone composition according to any of the preceding embodiments for the production of a curable silicone composition.

[0220] 20. Use of a non-curable silicone composition according to any of the preceding embodiments as a masterbatch to be incorporated into a curable silicone composition.

[0221] 21. Use of a non-curing silicone composition according to any of the preceding embodiments in high-voltage DC applications.

[0222] 22. A curable silicone composition comprising a non-curable silicone composition according to any of the preceding embodiments.

[0223] 23. A curable silicone composition according to the previous embodiment 22: a) 100 parts by weight of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2) b) Crosslinking agent component comprising 0 to 100 parts by weight of one or more polyorganohydrogensiloxanes, c) 0 to 100 parts by weight of one or more filler components, including one or more reinforcing silica or resin. d) 0.1 to 3 parts by weight of carbon black, one or more e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) A composition comprising 0 to 50 parts by weight of one or more auxiliary additives.

[0224] 24. A curable silicone composition according to the previous embodiment 22 or 23, comprising one or more carbon blacks d) in an amount of 0.1% to 2.4% by weight, preferably 0.2% to 2.4% by weight, more preferably 0.5% to 2.2% by weight, even more preferably 1.0% to 2.0% by weight, and even more preferably 1.3% to 1.8% by weight, based on the total weight of the entire silicone composition.

[0225] 25. A cured silicone composition obtained by curing a curable silicone composition according to any of the above embodiments 22 to 24.

[0226] 26. A cured silicone composition according to Embodiment 25, wherein in the PEA charge transfer diagram determined by the method described in the Examples, the transfer of any charge from one or each electrode is <0.2 mm, preferably <0.3 mm.

[0227] 27. A cured silicone composition according to Embodiment 25, wherein the peak maximum / minimum value of the transfer from one or each electrode in the PEA charge transfer diagram determined by the method described in the Examples is <0.05 mm, preferably <0.1 mm.

[0228] 28. A cured silicone composition according to Embodiment 25, wherein, in the total charge accumulation diagram (exemplified in Figure 13), the increase in average charge density up to a measurement time of 20 hours is less than 20%, preferably less than 10% (steady state) after 5 hours, preferably 2.5 hours.

[0229] 29. In the total charge accumulation diagram (exemplified in Figure 13), the maximum average charge density after 20 hours or thereafter is <1.5 C / m³. 3 Preferably <1.25 C / m 3 , and most preferably <1.0 C / m 3 A cured silicone composition according to Embodiment 25.

[0230] Preferably 1 × 10 in an electric field of 10 kV / mm to 30 kV / mm in the range of 30.25°C to 90°C. 11 Greater than Ωcm, more preferably 1 × 10⁻⁶ 13 Greater than Ωcm, more preferably 1 × 10⁻⁶ 16 Greater than Ωcm, and more preferably 1 × 10⁻⁶ 17 A value greater than Ωcm, preferably 1 × 10⁻⁶ 18 A cured silicone composition according to any one of embodiments 25 to 29, having a volume resistivity up to Ωcm.

[0231] 1 × 10⁻¹⁰ 11 and 1 x 10 19 Between Ωcm, preferably 1 × 10 11 and 1 x 10 18 Between Ωcm, preferably 1 × 10 13 and 1 x 10 18 Between Ωcm, more preferably 1 × 10 14 and 1 x 10 18 Between Ωcm, and most preferably 1 × 10 16 and 1 x 10 18 A cured silicone composition according to embodiment 25 or 29 having a volume resistivity between Ωcm.

[0232] 32. Based on the total weight of the curable silicone composition, one or more carbon blacks d) are present with a carbon black content of 1.0% to 2.3% by weight, and 1 × 10⁻¹⁶ in an electric field of 10kV / mm to 30kV / mm in the range of 25°C to 90°C. 16 and 1 x 10 18 A cured silicone composition according to any one of embodiments 25 to 31, having a volume resistivity between Ωcm.

[0233] 33. Use of a curable silicone composition according to any of the preceding embodiments for the manufacture of an insulator or field grading assembly for high voltage direct current (HVDC) applications.

[0234] 34. An insulator or field grading assembly for high-voltage DC applications obtained by curing a curable silicone composition according to any of the preceding embodiments.

[0235] 35. Cable accessories for high-voltage DC applications, including an insulator or field grading assembly according to the previous embodiment.

[0236] 36. Cable accessories according to the previous embodiment, selected from the group consisting of cable joints, cable terminations, and cable connectors, each for high-voltage DC applications.

[0237] 37. A cable joint according to embodiment 36, which seals the end of a cable having a thermoplastic polyolefin or rubber cable insulator.

[0238] 38. A curable silicone composition according to the previous embodiment 22: a) 100 parts by weight of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2) b) Crosslinking agent component comprising 0 to 100 parts by weight of one or more polyorganohydrogensiloxanes, c) 0 to 100 parts by weight of one or more filler components, including one or more reinforcing silica or resin. d) More than 2 parts by weight, preferably 4 to 12 parts by weight of carbon black, e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) A composition comprising 0 to 50 parts by weight of one or more auxiliary additives.

[0239] 39. A curable silicone composition according to the previous embodiment 22 or 28, comprising more than 2.4% by weight, preferably 3% to 10% by weight, of one or more carbon blacks d) based on the total weight of the entire silicone composition.

[0240] 40. A cured silicone composition obtained by curing a curable silicone composition according to either of the above embodiments 38 and 39.

[0241] 41. Use of cured silicone composition according to Embodiment 40 for the manufacture of connectors, electrically conductive films, electrode materials, heat dissipation materials, and electroactive elastomers.

[0242] Examples Unless otherwise specified, all parts are measured in parts by weight. Unless otherwise specified, all percentages are measured in weight percentages.

[0243] Masterbatch Example Masterbatch Example 1: Preparation of a non-curing masterbatch according to the present invention containing carbon black 20℃ and shear rate D=10s -1 In this product, vinyl-terminated linear polydimethylsiloxane (component a1) and carbon black (component d) with a viscosity of 10 Pa·s have a primary particle size of 40 nm (DBP pore volume 350 ml / 100 g) and a BET specific surface area of ​​800 m². 2Ketjenblack EC300J (Akzo) containing 1 / g was extruded at 25°C using a Leistritz ZSE40MAXX twin-screw extruder with an L / D ratio of 52 (where L is the length of the extruder and D is its diameter) and a screw diameter of 41.4 mm. Processing speed varied from 100 to 175 kg / h. The temperature of the extruded mass increased with increasing carbon black content, reaching over 230°C at very high carbon black content even with cylinder cooling.

[0244] The carbon black content was varied from 10% by weight to 23% by weight.

[0245] [Table 1]

[0246] Masterbatch Comparative Example 1: Preparation of a non-curing masterbatch containing carbon black according to Example 1 of WO2016 / 110570A1 20℃ and shear rate D=10s -1 In this experiment, 100 kg of vinyl-terminated linear polydimethylsiloxane with a viscosity of 10 Pa·s was placed in a planetary mixer, resulting in a primary particle size of 40 nm (DBP pore volume of 350 ml / 100 g) and a BET specific surface area of ​​800 m². 2 It was mixed with 12.7 kg of Ketjenblack EC300J (Akzo), a carbon black with a concentration of / g. This mixture was stirred in a twin-screw kneader, and a homogeneous mixture was obtained after 45 minutes.

[0247] Next, this homogeneous mixture was further dispersed in a three-roll mill for 30 minutes to obtain a carbon black dispersion.

[0248] [Table 2]

[0249] Measurement of particle size distribution in a masterbatch The particle size distribution of carbon black in the non-curing silicone compositions of Masterbatch Example 1 and Masterbatch Comparative Example 1 was measured by light scattering according to DIN EN ISO / IEC 17025 in a toluene solution using a scattering model following Mie theory, measured at the lowest rotation speed of the dispersion unit corresponding to the minimum shear force using a Malvern Panalytical Zetasizer apparatus. Figure 14 shows the particle size distribution (number percentage) of Masterbatch Comparative Example 1, and Figure 15 shows the particle size distribution (number percentage) of Masterbatch Example 1. As can be seen from the comparison of these two figures, Figure 14 and Figure 15, the particle size of carbon black aggregated particles in Masterbatch Example 1 of the present invention is significantly smaller than that of Masterbatch Comparative Example 1. In Masterbatch Example 1 of the present invention, there are almost no particles larger than about 10 μm, and the smallest particles are about 1 μm, whereas a considerable portion of Masterbatch Comparative Example 1 are larger than 10 μm, up to about 100 μm, and there are almost no particles smaller than about 3 μm. Surprisingly, this different particle size distribution of the masterbatch (non-curable silicone composition) of the present invention is considered effective in improving the electrical properties of the curable silicone composition of the present invention, particularly in high-voltage DC applications, as described below.

[0250] Examples of curable compositions Example SR1 and Comparative Example SR1

[0251] [Table 3]

[0252] Example SR1 (Curable Silicone Composition) The curable silicone rubber composition SR1 according to the present invention was prepared according to the following process:

[0253] Part A In a dissolver mixer, 9.47 parts of carbon black paste from masterbatch Example 1 and a shear rate of 10s at 20°C were mixed. -111.12 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of 10 Pa·s and 20.14 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (component a2) having a viscosity of 65 Pa·s were each mixed with 3.08 parts of hexamethyldisilazane (surface treatment agent - component c), 0.026 parts of divinyltetramethyldisilazane (surface treatment agent - component c), and 1.29 parts of water (additive - component f). This mixture was then prepared using a Brunauer-Emmett-Teller (BET) specific surface area of ​​300 m². 2 14.25 parts of fumed silica (Evonik Aerosil 300) (component c) at a concentration of 2.08 mmol / g were mixed and heated at 100°C for 1 hour to form a silica filler with a mixture of trimethylsilyl and vinyldimethylsilyl groups on its surface. The volatile compounds obtained by the water and surface treatment reaction were then removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. The resulting volatile components were then removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. This mixture was subsequently cooled and diluted with 39.13 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of 10 Pa·s. Subsequently, 3.97 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-co-methylvinylsiloxane) (component a) with a vinyl content of 2.08 mmol / g and a viscosity of 0.2 Pa·s were added. Finally, 0.2 parts of a Pt(0) complex solution of tetramethyltetravinylcyclotetrasiloxane containing 1.5 wt% Pt (Ashby catalyst) (component e) were added.

[0254] Part B In a dissolver mixer, 9.47 parts of carbon black paste from Masterbatch Example 1, 11.23 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (component a2) with a viscosity of 10 Pa·s, and 20.33 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane (component a2) with a viscosity of 65 Pa·s were mixed with 3.06 parts of hexamethyldisilazane (surface treatment agent - component c), 0.025 parts of divinyltetramethyldisilazane (surface treatment agent - component c), and 1.27 parts of water (additive - component f). This mixture was then mixed with a Brunauer-Emmett-Teller (BET) specific surface area of ​​300 m². 2 14.15 parts of fumed silica (Evonik Aerosil 300) (component c) at a concentration of / g were mixed and heated at 100°C for 1 hour to form a silica filler with a mixture of trimethylsilyl and vinyldimethylsilyl groups on the surface. The volatile compounds obtained by the surface treatment reaction with water were then removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. The resulting volatile components were then removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. The mixture was subsequently cooled and diluted with 28.51 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of 10 Pa·s. Next, 8.94 parts of a first crosslinking agent (linear poly(dimethyl)co(methylhydrogen)siloxane (component b)) with an SiH content of 4.15 mmol / g and a viscosity of 0.035 Pa·s, 5.54 parts of a second crosslinking agent (linear poly(dimethyl)co(methylhydrogen)siloxane (component b)) with an SiH content of 2.30 mmol / g and a viscosity of 0.21 Pa·s, and 0.12 parts of 1-ethynyl-1-cyclohexanol (ECH) (component f) were added.

[0255] The cured silicone rubber composition according to the present invention was prepared as follows: Parts A and B were mixed in a 1:1 weight ratio and cured by heating at 175°C for 10 minutes.

[0256] Comparative Example 1 (Curable Silicone Composition) Example SR1 (curable silicone composition) was repeated, except that the masterbatch from Comparative Example 1 was used in the amount shown in Table 3.

[0257] Additional curing composition For example, as described in Example SR1 and Comparative Example SR1 above, additional cured compositions were prepared using the non-curable masterbatch carbon black paste of the present invention and a non-curable masterbatch of the present invention, along with different amounts of carbon black, and various electrical properties were measured as described below.

[0258] Volume resistivity The volume resistivity of the cured composition was measured according to DIN EN 62631-3-1, and the test sheet was for high volume resistivity with an effective diameter of 31 mm and a thickness of 1 mm (approximately 10 14 (Higher than Wcm). Lower volume resistivity (approximately 10 14 For values ​​lower than Wcm, the volume resistivity was determined according to ISO 1853.

[0259] Conductivity method: Method according to DIN EN 62631-3-1, test setup according to IEC 60093 (high volume resistivity). For highly insulating materials, the measuring device used to determine the electrical conductivity or volume resistivity of the cured composition sample has a fundamental structure shown in Figure 3, employing a three-electrode arrangement and a protective ring. The dimensions of this configuration are shown in the table below, and according to this table, a sample thickness d=1mm was used for each measurement.

[0260] [Table 4]

[0261] Further parameters for the measurement are: • Electrode material: Brass • Do not use silver paste as a contact support. • Measured at different voltages as shown in the graph. • Formula for calculating volume resistivity:

[0262]

number

[0263] The measurement period is determined using a log-log plot of current against time, as theoretically shown in Figure 4. A steady state is achieved after 10 hours, and thus the measurement period is typically set to 20 hours.

[0264] Measurements were performed at room temperature unless otherwise specified. Electrodes were made of brass and polished before use. Conductive coatings (e.g., silver ink) were not used because silicone made good contact with the electrodes. For polarization, a Heinsinger PNChp-30000-2 type DC source was used at a maximum voltage of 30 kV / mm and a maximum current of 2 mA. The minimum detectable current was 1 fA (femtoampere). The highest resolution in this test setup was achieved at 10 fA.

[0265] Conductive method: ISO1853 (low volume resistivity) Figure 5 shows the fundamental settings for determining the volume resistivity of a weakly conductive elastomer in the corresponding dimensions according to ISO 1853. Further parameters are: • Electrode material: Brass • Do not use silver paste as a contact support. UDC=60V

[0266] The test sample was a strip 2 cm wide and 2 mm thick, with a distance of 2 cm between electrodes according to the ISO standard mentioned above. The measurement was performed at room temperature. Figure 1 shows the volume resistivity of the cured composition based on the carbon black content.

[0267] As shown in Figure 1, the cured composition of the present invention, prepared using the carbon black masterbatch of the present invention, surprisingly requires a larger amount of carbon black to reach the percolation point and shows the potential to be more conductive than the conventional carbon black masterbatch (comparative example). This makes it possible to add a larger amount of carbon black while maintaining electrical strength and insulating properties.

[0268] Dielectric breakdown voltage The dielectric breakdown voltages of compositions of the present invention and comparative examples with different amounts of carbon black were measured according to IEC60243-2. ​​Figure 6 shows the measurement configuration according to IEC60243-2.

[0269] The specific parameters were as follows: • Maximum voltage is 100kVDC • Sample thickness: 1 mm, diameter: 45 mm • Asymmetrical ball-shaped plate electrode configuration ·room temperature Measurement in Shell Diala S3ZX-I insulating oil dried according to IEC60243-2. • Voltage rise: 4kV / s

[0270] To avoid oil ingestion, a so-called short-time (rapid pressure increase) test according to IEC60243-2 was applied.

[0271] The power supply was capable of a maximum output voltage of 100kV, and when combined with a smoothing capacitor of Cg=10nF, it was possible to achieve a maximum output of 140kV. The so-called ripple component in DC remained below 1%. The test voltage was applied using a Northstar VD150 resistor-capacitor type voltage divider with a standard voltage division ratio of 10000:1 (DC error <0.1%).

[0272] The results are shown in Figure 2. As shown in Figure 2, the dielectric breakdown voltage of the cured silicone composition of the present invention can be maintained well above 50 kV / mm until the carbon black content reaches 2% by weight. This determines the electrical stress resistance under standard conditions. This parameter is a key factor for the functionality of cable joint insulation materials. Since dielectric breakdown percolation occurs earlier than volume resistivity percolation, this is more critically important for fine-tuning the material. Electrical dielectric breakdown of the material causes failure of the entire cable joint, rendering the material unsuitable. In the measurement of a 1 mm test specimen, it is necessary to reach at least 40-50 kV / mm.

[0273] PEA measurement Pulsed electrostatic stress (PEA) measurements are used to localize charges within materials, such as silicone sheets. This allows for the measurement of charge movement over time within a material caused by polarization current at a given temperature. This method is crucial for the development and justification of insulating materials (cable accessories) for HVDC applications. It should be noted that all samples had a thickness of 1 mm, and no silicone oil or grease was used at the sample interface, as it was observed that silicone oil / grease migrated into the LSR. A new depolarized LSR sample was used for each parameter combination. In the case of PEA, elastic wave impulses are generated directly in the space charge field, making it possible to determine the charge location via the velocity of the elastic wave. This electrical impulse is a voltage impulse, creating a short-duration electric field E inside the sample. pIt generates a Coulomb force, and then a pressure impulse, which acts on the space charge, although it is so short that it does not cause further polarization. This impulse spreads as an elastic wave through the sample until it reaches the piezoelectric film, which converts the elastic wave into an electrical signal.

[0274] Figure 7 shows a schematic PEA test configuration, where e(t) represents the electrical impulse that generates an elastic wave as a function of time within the sample. The piezoelectric element is the detector in this system, and its back surface is filled with an absorbent material to delay any reflections that may occur and prevent interference with the initial pressure wave signal. The initial pressure wave is generated at t0 (see Figure 8) and then travels through the sample to the Al electrode of known thickness and impedance. The front-end signal of the sample reaches the piezoelectric foil at t1, while the rear-end signal arrives at t2. Subsequent signals are intentionally delayed reflected signals from within the measuring device (t3, t4).

[0275] After correcting for system response and other factors including calibration, the transformation to spatial coordinates (1D) essentially gives the charge density as a function of position (x) in the following pattern. The total charge density (Q) can be calculated as follows.

number

[0276] Figure 9 shows the conversion from a voltage oscillogram to a charge density diagram (sample thickness: 1 mm); The temperature is as specified individually, and the polarization current is as specified individually.

[0277] A detailed description of the overall setup and signal processing for PEA (pulsed electrostatic stress) measurements is provided below: 1) R. Hussain, J. Moxter, and V. Hinrichsen, "Development and Optimization of a Pulsed Electrostatic Stress System Suitable for Silicone Rubber with Carbon Black Nanofillers," 10th International Conference on Insulated Power Cables, Session C4-1, Paris, 2019; 2) R. Hussain and V. Hinrichsen, "Development and Optimization of a Pulsed Electrostatic Stress System with Temperature-Controlled Electrodes," 26th Nordic Materials Insulation Symposium, Components and Analysis, Tampere, Finland, 2019; 3) GC Montanari and D. Fabiani, "Evaluation of DC insulation performance based on space charge measurement and accelerated lifetime testing," IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 7, No. 3, June 2000, pp. 322-328; 4) Antti Penttinen, "Design of a pulsed electrostatic stress measurement system for evaluating space charge properties," Master's thesis, University of Lappeenranta, 2012, further 5) R. Hussain, "Electrical properties of liquid silicone rubber with carbon black nanofiller for HVDC cable accessories," Doctoral dissertation, Darmstadt University of Technology (scheduled for publication in 2020).

[0278] PEA measurement is a method to demonstrate the concept of charge trapping, which creates a kind of charge barrier that prevents the injection of charge into the material and thus protects cable joints from dielectric breakdown. The greater the amount of charge trapping, the stronger the construction of this charge barrier (so-called homocharge). According to this invention, carbon black (CB) is used as a charge trapping material because the potential wells for charge are relatively deep and high energy is required to extract the charge from the potential wells. This also allows the charge to be retained at the injection site, and the retained charge is also prevented from moving further into the material, thus constructing the aforementioned charge barrier.

[0279] Figure 10 shows the charge transfer diagram of PEA in comparative example SR1 (0.47% CB) cured at 60°C and polarization times t=10s and t=20h.

[0280] Figure 11 shows the charge transfer diagram of PEA in comparative example SR1 (0.47% CB) at 20°C and polarization times t=10s and t=20h.

[0281] Figures 10 and 11 examine the acceptable dielectric breakdown voltage and volume resistivity of Comparative Example SR1, which allows only about 0.5 wt% carbon black as an additive. This amount already shows a reduction in charge transfer into the bulk material compared to LSR without carbon black filling (see Figure 12). However, the charge barrier properties of these filling grades are insufficient for 525 kV cable joints for DC applications.

[0282] Figure 12 shows the PEA charge transfer diagrams at 20°C and 60°C and polarization time t=20h for cured example SR1 (1.52% CB) of the present invention, example SR of the present invention with a CB content of 0.75 wt%, and a cured composition without CB (0 wt% CB).

[0283] Figure 12 was derived according to the mathematical correlation described in R. Hussain's doctoral dissertation (see references above).

[0284] The embodiment of the present invention of cured silicone composition SR1 (Figure 12) exhibits significantly different behavior from the comparative example of cured silicone composition SR1 (Figures 10 and 11). The CB-unfilled LSR allows for maximum migration into the bulk material, which leads to dielectric breakdown over time under DC conditions. The embodiment of the present invention shows almost no migration over time, even at high temperatures, enabling its use as an insulating material in DC applications.

[0285] Preferably, the cured silicone composition SR according to the present invention has a PEA charge transfer diagram determined according to the method described above, in which the transfer for any charge is <0.2 mm, preferably <0.3 mm, from one or each electrode.

[0286] Preferably, the cured silicone composition SR according to the present invention has a maximum / minimum peak migration from one or each electrode of <0.05 mm, preferably <0.1 mm, in the PEA charge transfer diagram determined according to the method described above.

[0287] Total charge accumulation diagram: The average charge density is calculated at a given time point according to the following formula.

number

[0288] The resulting diagrams are shown in Figure 13 for the SR examples and various CB concentrations of the present invention. The examples with higher CB addition levels already show a steady state after several hours, where no further charge accumulation or increase in charge density occurs. Lower concentrations (and comparative examples) have significantly higher final average charge density values, and a steady state is reached much later (0.75% and 1.08% carbon black) or not even after 20 hours (0.5% and 0% carbon black).

[0289] The behavior of space charge (mobility and maximum average charge density) ultimately depends on the amount of filler added. However, the CB masterbatch extrusion process of the present invention (Example 1) allows for higher CB additions than the comparative CB masterbatch, in terms of volume resistivity and dielectric breakdown voltage.

[0290] For safe operation, it is crucial to reach a steady state (where there is no further increase in charge density) as quickly as possible (Figure 13). A steady state indicates a condition where no further charge transfer occurs within the silicone elastomer intended for DC applications. In addition, the maximum charge density must be kept as low as possible to minimize the level of charge injection into the silicone material. In such a case, a homocharge barrier is formed most efficiently, avoiding damage to the insulating silicone elastomer.

[0291] The cured silicone composition according to the present invention shows an increase of less than 20%, preferably less than 10%, in the average charge density from preferably 5 hours, more preferably 2.5 hours, to a measurement time of 20 hours, as illustrated in the total charge accumulation diagram (exemplarily shown in Figure 13). This means that the cured silicone composition according to the present invention preferably reaches a steady state after preferably 5 hours, more preferably 2.5 hours, in the total charge accumulation diagram.

[0292] The curing silicone composition according to the present invention preferably has a total charge accumulation diagram (exemplarily shown in Figure 13) of <1.5 C / m² after 20 hours or thereafter. 3 Preferably <1.25 C / m 3 And most preferably <1.0 C / m 3 It has the maximum average charge density.

Claims

1. A method for manufacturing an insulator or field grading assembly for high-voltage DC applications obtained by curing a curable silicone composition, wherein the curable silicone composition is manufactured using a non-curable silicone composition as a masterbatch to be incorporated into the curable silicone composition, and the manufacturing process of the masterbatch comprises extruding one or more polyorganosiloxanes a1) with one or more carbon blacks d) using a multi-screw extruder.

2. The method of claim 1, wherein polyorganosiloxane a1) is selected from polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups.

3. The method according to claim 1 or 2, wherein the extrusion is performed in a twin-screw extruder, preferably a twin-screw extruder with simultaneous rotation.

4. The method of any one of claims 1 to 3, wherein the weight ratio of one or more polyorganosiloxane a1) to the weight of one or more carbon black d) is 90:10 to 75:25, preferably 89:11 to 80:

20.

5. The method according to any one of claims 1 to 4, wherein the non-curing silicone composition as a masterbatch contains at least 10 weight percent, preferably at least 11 weight percent, more preferably at least 12 weight percent, of one or more carbon blacks d) based on the total weight of the entire masterbatch, and / or contains 10 to 25 weight percent, preferably 11 to 24 weight percent, more preferably 12 to 23 weight percent, of one or more carbon blacks d) based on the total weight of the entire masterbatch.

6. The method according to any one of claims 1 to 5, wherein in the non-curable silicone composition as a masterbatch, the proportion of particles less than 10 μm is more than 70%, preferably more than 80%, more preferably more than 90%, as determined by dynamic light scattering, and / or the proportion of particles greater than 10 μm is less than 30%, preferably less than 20%, more preferably less than 10%, and more preferably less than 5%, and / or the Dn50 of the particle size distribution based on the number of particles in the non-curable silicone composition is preferably less than 7 μm, more preferably less than 5 μm, and most preferably less than 3 μm, and / or the Dn90 of the particle size distribution based on the number of particles in the non-curable silicone composition is preferably less than 15 μm, more preferably less than 10 μm, more preferably less than 8 μm, and most preferably less than 5 μm.

7. The method of any one of claims 1 to 6, wherein the insulator or field grading assembly for high-voltage DC applications is for use in high-voltage DC applications.

8. A method according to any one of claims 1 to 7, wherein the curable silicone composition is: a) 100 parts by weight of one or more polyorganosiloxane a2 having one or more unsaturated groups, preferably one or more alkenyl groups. b) 0 to 100 parts by weight of a crosslinking agent component comprising one or more polyorganohydrogensiloxanes, c) 0 to 100 parts by weight of one or more filler components comprising one or more reinforcing silica or resin, d) 0.1 to 3 parts by weight of one or more carbon black, e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) A method comprising 0 to 50 parts by weight of one or more auxiliary additives.

9. The method according to any one of claims 1 to 8, wherein the curable silicone composition comprises 0.1% to 2.4% by weight, preferably 0.2% to 2.4% by weight, more preferably 0.5% to 2.2% by weight, even more preferably 1.0% to 2.0% by weight, and even more preferably 1.3% to 1.8% by weight, of one or more carbon blacks d) based on the total weight of the entire silicone composition.

10. A method according to any one of claims 1 to 9, wherein the curable composition is: a) 100 parts by weight of one or more polyorganosiloxane a2 having one or more unsaturated groups, preferably one or more alkenyl groups. b) 0 to 100 parts by weight of a crosslinking agent component comprising one or more polyorganohydrogensiloxanes, c) 0 to 100 parts by weight of one or more filler components comprising one or more reinforcing silica or resin, d) One or more carbon black in amounts exceeding 2 parts by weight, e) A curing catalyst selected from the group consisting of compounds that enable hydrosilylation and organic peroxides, and f) 0 to 50 parts by weight of one or more auxiliary additives A method that includes this.

11. An insulator or field grading assembly for high-voltage DC applications obtained by any of claims 1 to 10.

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