Non-silica filled non-curable silicone composition

Abstract

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

Description

[0001] describe

[0002] This invention relates to a method for manufacturing a non-curing silicone composition containing carbon black, the non-curing silicone composition obtained by the method, and its use in manufacturing curing silicone compositions (particularly for high voltage direct current applications).

[0003] Standard silicones are widely used in AC high-voltage (HV) industries. However, these materials are unsuitable for the emerging trend of DC applications. The use of carbon black (CB) as a filler material provides silicones with advantageous properties, with standard CB pastes, established over many years, showing positive test results for operating voltages up to 325 kV. This standard CB paste is produced via three-roll mill technology or a two-blade kneader (US20170372815A1).

[0004] However, the inventors have found that at higher voltages of up to 500kV, there are limitations due to the breakdown of the modified organosilicon system.

[0005] Furthermore, current conductive liquid silicone rubbers (LSRs) are very limited in their ability to alter mechanical properties and, in some cases, have insufficient electrical conductivity.

[0006] Organosilicon compositions containing carbon black as a filler are disclosed, for example, in the following prior art documents:

[0007] WO2016 / 110570 and US20170372815A1 respectively disclose the use of organosilicon compositions comprising the following:

[0008] a) at least one polyorgano-based polysiloxane having an alkenyl group,

[0009] b) A crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes.

[0010] c) Contains one or more filler components for reinforcing with silica or resin.

[0011] d) at least one dielectric active compound, and

[0012] e) Solidification catalyst

[0013] The dielectric active compound d) may be selected from carbon black.

[0014] That is, they disclosed the use of curable silicone compositions, while this application relates to the use of non-curable silicone compositions.

[0015] In addition, WO2016 / 110570 discloses a method for manufacturing an insulator or field grading assembly, which includes forming the above-mentioned silicone composition by extrusion through a nozzle or die, and then curing the formed composition by heat or light.

[0016] Although this application relates to methods including extruding non-curable silicone compositions containing carbon black and cured silicone compositions containing such specific non-curable carbon black silicone compositions obtained by methods including an extrusion step, resulting in improved properties of the cured silicone compositions for DC applications based on such carbon black paste, WO2016 / 110570 and US20170372815A1 disclose extrusion as a means of shaping cured silicone compositions as defined above.

[0017] US2004 / 138370A1 discloses an organosilicon composition for use as a conductive liquid rubber composition in, for example, a printer, comprising:

[0018] a) Polyorgano-based polysiloxanes with alkenyl groups,

[0019] b) At least one dielectric active compound, i.e., carbon black

[0020] c) Solidification of catalyst

[0021] d) A crosslinking agent comprising an organo-based polysiloxane having two or more silicon-bonded hydrogen atoms in one molecule.

[0022] The above-mentioned components are preferably supplied continuously to a mixing device. The mixing device may be an extruder, etc.

[0023] Therefore, although extrusion is a mandatory step in providing non-curing carbon black silicone paste in this application, US2004 / 138370A1 discloses that the mixing step of all components constituting the curing silicone composition described therein can be carried out by an extruder.

[0024] WO2020 / 063799A1 relates to a conductive liquid silicone rubber composition comprising carbon black, wherein:

[0025] a) One or more polydiorganosiloxanes having at least two alkenyl groups per molecule

[0026] b) At least one organic-based hydrogen polysiloxane.

[0027] c) At least one reinforcing filler

[0028] d) at least one hydrogenation silylation catalyst, and

[0029] e) Conductive filler, which contains

[0030] (i) Superconducting carbon black, and

[0031] (ii) Single-walled carbon nanotubes.

[0032] That is, it involves a curable silicone rubber composition.

[0033] For this type of cured silicone rubber composition, extrusion is used as a means of processing or forming the aforementioned cured silicone rubber composition, and therefore serves a different purpose than that of this application, which relates to the manufacture of non-curing carbon black silicone masterbatch using an extrusion process.

[0034] WO2009 / 027133A2 relates to a method for manufacturing a molded, cured silicone article, comprising a molding step including the continuous molding of a cured silicone mixture. According to the disclosure of this document, a portion of the mixture, i.e., a portion of the uncured mixture of the following components (soluble in CDCl3 at 25°C), has an ortho-silyl group content of less than 0.025 mol%:

[0035] (i) at least one linear polyorganosiloxane having at least three alkenyl groups and having an average number of at least 3000 diorganosiloxy units as determined by GPC using polystyrene as a standard.

[0036] (ii) Optionally, one or more polyorganosiloxanes having an alkenyl group, different from the polyorganosiloxanes according to component (i).

[0037] (iii) at least one polyorganosiloxane having at least two SiH groups,

[0038] (iv) at least one photoactivated transition metal catalyst,

[0039] (v) Optionally, one or more fillers.

[0040] (vi) Optionally, one or more conventional additives.

[0041] In contrast to the inventions covered by this application relating to methods for manufacturing non-curable organosilicon compositions containing carbon black, the mixture of compounds (i) to (vi) above represents a curable mixture containing all the compounds required for the organosilicon composition to be cured: alkenyl polysiloxane (i), SiH-functionalized polysiloxane (iii), and photoactivated transition metal catalyst (iv).

[0042] Although the presence of carbon black in the mixture of the method of the present invention is mandatory, the presence of filler component (v) in the mixture is optional.

[0043] Furthermore, WO 2009 / 027133 A2 relates to a method comprising continuously molding the aforementioned mixture, wherein the continuous molding step of the uncured mixture is an extrusion step, and therefore the molding equipment is an extruder. In the embodiments of WO 2009 / 027133, the extrusion of a curable silicone composition is illustrated by way of example.

[0044] Contrary to the disclosure of WO 2009 / 027133 A2, the composition manufacturing method involved in this application includes extruding one or more polyorganosiloxanes and one or more carbon blacks, that is, the present invention relates to a method including extrusion of non-curing compositions.

[0045] Therefore, the inventors have conducted extensive research to improve upon the shortcomings of prior art organosilicon compositions in terms of their electrical and mechanical properties.

[0046] Surprisingly, they found that when the CB paste was processed using extrusion technology, it exhibited significantly different behavior compared to conventional CB paste. The CB nanoparticles were distributed much more uniformly in the silicone material, resulting in many surprisingly improved electrical properties in the cured silicone rubber compositions thus prepared. A finer CB particle size distribution than that achieved with conventionally prepared CB paste was also obtained through the extrusion process.

[0047] Compared to conventionally prepared CB pastes, the novel CB paste of this invention allows for the incorporation of significantly higher amounts of carbon black into the cured silicone rubber composition without reaching the so-called critical percolation threshold where resistivity rapidly decreases. This allows for the incorporation of even more carbon black into the cured silicone composition when used as an insulator with the same (or even higher) resistivity levels. Consistently, the cured silicone rubber composition includes a higher concentration of charge trapping, which allows for reduced electrical stress, particularly under DC conditions. Consequently, the electrical properties obtained from the cured silicone composition provide greater confidence for operation in DC systems at market-demanded ultra-high voltages (e.g., 500 kV).

[0048] Furthermore, regarding conductive silicone rubber compositions, the novel CB paste of this invention allows for the incorporation of higher amounts of carbon black into the curable silicone. Therefore, the extruded CB paste allows for the use of high concentrations of CB in conductive LSRs, thereby improving mechanical properties. This allows for the provision of silicone rubber compositions with good mechanical properties and (if desired) very high conductivity, particularly for use in high-voltage direct current applications, especially for one or more layers in cable accessories.

[0049] According to the present invention, a method for manufacturing a non-curable organosilicon composition comprising carbon black is provided, the method comprising extruding one or more polyorganosiloxanes (a1) together with one or more carbon blacks (d).

[0050] According to the present invention, the term "non-curing silicone composition" means that the silicone composition does not contain the components required for curing the silicone composition under common polysiloxane curing conditions. Given the typical silicone rubber curing modes, including hydrosilane curing systems (e.g., platinum-catalyzed curing systems), or addition curing systems, condensation curing systems, peroxide curing systems, or oxime curing systems, the non-curing silicone compositions obtained according to the present invention do not contain the components required to achieve such curing, and in particular, of course, they are also not included in the extrusion process. Therefore, for hydrosilane curing systems, such as platinum-catalyzed addition curing systems, the non-curing silicone composition cannot simultaneously contain a hydrogen-functionalized (hydride) polysiloxane, an alkenyl-functionalized polysiloxane, and a hydrosilane alkylation catalyst, and preferably only contains alkenyl-functionalized polysiloxanes. Similarly, the non-curing silicone composition cannot contain peroxides that cure polyorganosiloxanes (a1). Therefore, preferably, the non-curing organosilicon composition of the present invention does not contain polyorgano-based hydrosiloxanes or hydrosilane curing catalysts, and preferably it contains neither polyorgano-based hydrosiloxanes nor hydrosilane curing catalysts, nor peroxides.

[0051] In a preferred embodiment, the total viscosity of one or more polyorganosiloxanes (a1) is less than 100, preferably 1-100 Pa·s, more preferably 5-100 Pa·s, and even more preferably 10 or 65 Pa·s (each at 20°C with D=10 s⁻¹). -1 The shear rate is measured, for example, according to DIN EN ISO 3219. In this regard, the term "total viscosity" refers to the viscosity of the entire polyorganosiloxane (a1) if more than one polyorganosiloxane is used, or to the viscosity of a single polyorganosiloxane (a2) if only one polyorganosiloxane (a1) is used. In the former case, the viscosity of the individual polyorganosiloxane (a1) may deviate from the preferred viscosity range indicated above. In a preferred embodiment, the polyorganosiloxane (a1) is selected from polyorganosiloxanes having one or more unsaturated groups (preferably one or more alkenyl groups) as described below. This polyorganosiloxane (a1) has an organic substituent R preferably selected from: optionally substituted alkyl (e.g., alkyl and haloalkyl), optionally substituted aryl (e.g., phenyl), and unsaturated substituent R. 1 (Preferably selected from alkenyl groups, such as vinyl groups), and preferably having an average degree of polymerization P of 100 to 12,000 silanoxy units. nRegarding such polyorganosiloxanes (a1), which, when used in the following curable silicone compositions, may be referred to as alkenyl-containing polyorganosiloxanes (a2). The method according to the invention comprises mixing one or more polyorganosiloxanes (a1) with one or more carbon blacks (d) and extruding. Basically, several extruders can be used, such as commonly known single-screw extruders, twin-screw extruders, and planetary roller extruders. Single-screw extruders are less preferred because of their weaker homogenization and dispersion. While planetary roller extruders offer excellent mixing compared to all other extruder types, their conveying performance is much lower. Therefore, in this invention, twin-screw extruders, particularly co-rotating twin-screw extruders, are preferred, both in terms of homogenization and dispersion and in terms of conveying performance. In principle, a premixture of components a1) and d) can be prepared and then fed into the extruder via a suitable dosing unit, but preferably components a1) and d) are fed separately via a split-feed process using at least two, preferably two, dosing units. Preferably, the extruder has two feeding sections, the first of which is preferably for the polyorganosiloxane a1), which typically forms a viscous fluid at room temperature. It can be fed, for example, using a twin-screw feeder (such as a twin-screw loss-in-weight feeder) or a dosing system (such as a piston drum pump or gear pump). One or more carbon blacks d) are fed downstream of the polyorganosiloxane feeding unit via one or more, preferably one or two dosing units (e.g., gravity feeders). The carbon black dosing unit is preferably arranged in the extruder where the polyorganosiloxane is entirely liquid to allow for the distribution and dispersion mixing of the carbon black and the polyorganosiloxane.

[0052] Extrusion is typically carried out at extrudate temperatures ranging from room temperature (25°C) to 250°C, preferably in the range of 50 to 200°C. The melting and homogenization processes in the extruder are preferably carried out without providing heat generated by the shear forces within the extruder. Optionally, external heat may be provided, but even more preferably, external cooling may be provided to prevent temperatures that could lead to the decomposition of the polyorganosiloxane, especially under high carbon black loadings. Extrusion is preferably carried out using one or more of the following conditions:

[0053] - Twin screws rotating in the same direction

[0054] - The screw diameter is in the range of 15 to 250 mm, preferably 20 to 100 mm.

[0055] - The feed rate is approximately 1 to 600 kg / h, preferably 100 to 550 kg / h, and more preferably 10 to 50 kg / h.

[0056] - The screw speed is 50 to 1200 rpm, preferably 100 to 1000 rpm.

[0057] - The temperature of the extruded material is 50 to 200°C.

[0058] The L / D ratio is 20 to 80, preferably 30 to 70 (where L is the length of the extruder and D is its diameter).

[0059] - The dwell time is 10 seconds to 10 minutes, preferably 15 seconds to 2 minutes.

[0060] -Use cylinder cooling

[0061] - Use screw elements with segmented designs that allow for strong dispersion geometry.

[0062] The preferred extruder is, for example, the ZSE MAXXSERIES co-rotating twin-screw extruder from Leistritz Extrusionstechnik GmbH, Nuremberg Germany, which uses a highly dispersive screw with a screw diameter of 15 to 250 mm, preferably 20 to 100 mm.

[0063] In the extrusion method of the present invention, the weight ratio of one or more polyorganosiloxanes (a1) to one or more carbon blacks (d) is preferably 90:10 to 75:25, more preferably 89:11 to 80:20, and even more preferably 88:12 to 81:19.

[0064] In a preferred embodiment, only one or more polyorganosiloxanes (a1) and one or more carbon blacks (d) are extruded, or in other words, no other components are present during the extrusion process. Furthermore, in a preferred embodiment, only one polyorganosiloxane (a1) and one carbon black (d) are extruded to prepare a high-load carbon black with an excellent uniform particle size distribution in the polysiloxane masterbatch, which is also finer than the particle size distribution obtained by conventional processes.

[0065] In another aspect, the present invention relates to non-curing silicone compositions obtained by the method of the present invention. Such "non-curing compositions" are sometimes also referred to as "masterbatches".

[0066] The non-curing silicone composition according to the invention preferably contains at least 10, preferably at least 11, more preferably at least 12% by weight, even more preferably at least 13% by weight, and even more preferably at least 14% by weight of one or more carbon blacks (d) based on the total weight of the entire silicone composition.

[0067] The non-curing silicone composition according to the invention preferably comprises 10 to 25, more preferably 11 to 24, even more preferably 12 to 23% by weight, even more preferably 13 to 22% by weight, and even more preferably 14 to 21% by weight of one or more carbon blacks (d) based on the total weight of the whole silicone composition.

[0068] While it is generally preferred that the "non-curing composition" or carbon black "masterbatch" contains a higher amount (d) of one or more carbon blacks based on 10-25% by weight of the total weight of the entire silicone composition, non-curing compositions with a lower amount of carbon black, such as 3-10% by weight of one or more carbon blacks based on the total weight of the entire silicone composition, can also be prepared if desired. Moreover, those non-curing compositions with a lower amount of carbon black benefit from a more uniform and finer particle size distribution achieved through the extrusion process.

[0069] Preferably, the non-curing silicone composition according to the present invention comprises one or more polyorganosiloxanes (a1) and one or more carbon blacks (d), and even more preferably it comprises a polyorganosiloxane (a1) and a carbon black (d).

[0070] In this invention, one or more carbon blacks (d) preferably comprise at least one carbon black selected from those with a BET surface area > 30 μm. 2 / g and average primary particle size D 50 The conductive carbon black is 5 to 500 nm. Even more preferably, the carbon black component d) in the non-curable composition according to the invention has a BET surface area > 30 nm. 2 / g and / or average primary particle size D 50 The composition consists of conductive carbon black with a particle size of 5 to 500 nm. Typically, in the non-curing silicone compositions of the invention, it is necessary to distinguish between the primary particle size and the agglomerate particle size of the carbon black. Although the primary particle size or diameter of the primary carbon black is preferably in the range of 5 to 500 nm, the agglomerate particle size in the non-curing silicone compositions of the invention, particularly as determined by light scattering methods, is generally greater than about 0.5 μm, and preferably substantially in the range of about 0.5 to about 10 μm, more preferably substantially in the range of about 1 to about 10 μm.

[0071] The particle size distribution of carbon black in non-curing silicone compositions can be specifically measured in toluene solution by light scattering according to DIN EN ISO / IEC 17025, using a scattering model based on Mie theory at the lowest possible dispersion unit rotation speed (corresponding to the lowest possible shear). Preferably, the results are presented as a superposition of one or more measurements over a time period of 5-15 minutes. Measurements can be performed using a Malvern Zetasizer device, in particular. This method provides the quantity or volume percentage of the particle size distribution.

[0072] It has been demonstrated that, compared to conventional masterbatches produced via three-roll mill technology or a two-blade kneader, the extrusion process according to the invention surprisingly results in a significant increase in the number of particles smaller than 10 μm, even under high carbon black loading. Without being bound by theory, it is speculated that the extrusion process according to the invention leads to better deagglomeration or distribution of carbon black particles in the CB silicone masterbatch.

[0073] Preferably, the percentage of particles smaller than 10 μm is greater than 70%, more preferably greater than 80%, and even more preferably greater than 90%. Preferably, the percentage of particles larger than 10 μm is less than 30%, more preferably less than 20%, even more preferably less than 10%, and even more preferably less than 5%.

[0074] Dn based on the particle size distribution of the number of particles in the non-curing silicone composition 50 Preferably less than 7μm, more preferably less than 5μm, and most preferably less than 3μm.

[0075] Dn based on the particle size distribution of the number of particles in the non-curing silicone composition 90 Preferably less than 15 μm, more preferably less than 10 μm, even more preferably less than 8 μm, and most preferably less than 5 μm.

[0076] Dn 50 It is a dimension measured in micrometers, which divides the quantity distribution into the upper and lower halves of that diameter. The Dn used... 50 It is the median of the quantity distribution. For Dn 90 90% of the particles have a size smaller than this diameter. (See https: / / www.horiba.com / uk / scientific / products / particle-characterization / education / general-information / data-interpretation / understanding-particle-size-distribution-calculations / ).

[0077] In the non-curing silicone composition according to the invention, one or more carbon blacks are particularly preferred to include at least one carbon black selected from conductive carbon blacks having one or more of the following properties:

[0078] • BET surface area >100-1500m² 2 / g, more preferably >100-1400m 2 / g, more preferably >100-1000m 2 / g, more preferably >250-1000m 2 / g, more preferably >500-1000m 2 / g, and / or

[0079] Particle size D 50 The wavelength is 5-500nm, more preferably 10-200nm, and / or

[0080] • DBP orifice volume 300-600ml / 100g, more preferably 300-550ml / 100g, even more preferably 300-400ml / 100g, and / or

[0081] • Iodine adsorption of 700-1200 mg / g, more preferably 700-1150 mg / g, even more preferably 700-1000 mg / g, even more preferably 700-900 mg / g, and / or

[0082] • pH 8-11, more preferably pH 9-11, even more preferably pH 9-10.5 and / or

[0083] • Metal content <50ppm, and / or

[0084] • Sulfur content <150ppm, and / or

[0085] • Water content <0.5wt%, and / or

[0086] • Volatile content <1 wt%, and / or

[0087] • Fine particles <125 micrometers in the granules <10wt%, and / or

[0088] • Grit content: <50 mg / kg, and / or

[0089] Ash content: <0.1wt%.

[0090] Preferably, the one or more carbon blacks are composed of at least one, preferably one, selected from the following: conductive carbon black having one or more of the above-mentioned properties.

[0091] In another aspect, the present invention relates to the use of a non-curing silicone composition as defined above for the manufacture of a curing silicone composition. This use typically requires the final mixing of the non-curing silicone composition with components required for the manufacture of the curing silicone composition, particularly those described below. Therefore, the present invention also relates in another aspect to the use of the non-curing silicone composition as defined above as a masterbatch for incorporation into a curing silicone composition. As is well known to those skilled in the art, masterbatches are generally solid additives used for coloring plastics (color masterbatches) or imparting other properties to plastics (additive masterbatches). In the present invention, the masterbatch is preferably used, but not limited to, incorporating one or more carbon blacks (d) into the curing silicone composition described below.

[0092] Due to its high homogeneity, the non-curing silicone composition according to the invention and the resulting beneficial electrical properties, the non-curing silicone composition (masterbatch) according to the invention is particularly suitable for high voltage direct current applications, i.e., especially for the manufacture of curing silicone compositions for high voltage direct current applications.

[0093] Therefore, in another aspect, the present invention relates to curable silicone compositions comprising, as described above, non-curable silicone compositions according to the present invention.

[0094] Particularly preferred curable silicone compositions comprising the non-curable silicone composition according to the present invention include:

[0095] a) 100 pt.wt. (parts by weight) of one or more alkenyl-based polyorganosiloxanes a2),

[0096] b) A crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes, 0–100 pt.wt., preferably >0 to 100 pt.wt.

[0097] c) One or more filler components, 0–100 pt.wt., preferably >0 to 100 pt.wt., comprising one or more reinforcing silica or resins.

[0098] d) One or more carbon blacks of 0.1–3 pt.wt., preferably 0.2–2.8 pt.wt., more preferably 0.3–2.7 pt.wt., more preferably 0.4–2.6 pt.wt., more preferably 0.5–2.5 pt.wt., more preferably 0.6–2.3 pt.wt., more preferably 0.8–2.1 pt.wt.

[0099] e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and

[0100] f) One or more auxiliary additives, 0–50 pt.wt.

[0101] Preferably, the curable organosilicon composition of the present invention comprises a crosslinking agent component, said crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes.

[0102] Preferably, the curable organosilicon composition of the present invention comprises one or more filler components, said filler components comprising one or more reinforcing silica or resin.

[0103] This curable silicone composition preferably contains 0.1-2.5 wt%, preferably 0.2-2.4 wt%, more preferably 0.3-2.3 wt%, more preferably 0.4-2.2 wt%, more preferably 0.5-2.1 wt%, more preferably 0.6-2.0 wt%, more preferably 0.7-1.9 wt%, more preferably 0.8-1.8 wt% of one or more carbon blacks (d), based on the total weight of the curable silicone composition, such carbon blacks (d) are obtained from a non-curable silicone composition containing it, i.e., from a masterbatch.

[0104] This curable silicone composition with a relatively low carbon black content has relatively low conductivity and is particularly suitable for use as an insulator or field equalization component in high voltage direct current (HVDC) applications, as described in more detail below.

[0105] The components of the curable organosilicon composition according to the present invention are described below. As described above, one or more polyorganosiloxanes (a1) are preferably selected from polyorganosiloxanes (a2) having an alkenyl group as described below. The polyorganosiloxane (a1) and the polyorganosiloxane (a2) having an alkenyl group may be the same or different.

[0106] Alkenyl-based polyorganosiloxane a2 )

[0107] The curable organosilicon composition comprises one or more polyorganosiloxanes (a2) having one or more alkenyl groups, preferably at least two alkenyl groups, as a base polymer.

[0108] Preferably, the polyorganosiloxane (a2) is selected from one or more polyorganosiloxanes having an organic substituent R (i.e. having at least one carbon atom and bonded to a silicon atom by the carbon atom), wherein the organic substituent R is preferably selected from optionally substituted alkyl groups (e.g., methyl or haloalkyl such as fluorinated propyl), optionally substituted aryl groups (e.g., phenyl), and one or more alkenyl groups R. 1 (especially vinyl groups), and the average degree of polymerization (P) n The number of silanoxy units ranges from 100 to 12,000, and is specifically calculated by the number-average molecular weight (which can be determined by GPC measurement relative to the polystyrene standard, in particular following the procedure of ASTM D5296–11).

[0109] As a component a2) having alkenyl groups, the polyorganosiloxane preferably has an average of at least two alkenyl groups.

[0110] Suitable component a2) can be described by general formula (I).

[0111] (M a D b T c Q d R 2 e ) m (I)

[0112] In formula (I), the exponents represent the ratio of silanoxy units M, D, T, and Q, which can be block-formed or randomly distributed in the polyorganosiloxane. Within the polyorganosiloxane, each siloxane unit can be identical or different, and

[0113] a = 0 - 10

[0114] b = 0 - 12000

[0115] c = 0-50

[0116] d = 0 - 1

[0117] e = 0 - 300

[0118] m = 1 – 1000,

[0119] Among them, the indices a, b, c, d, and m make the viscosity of component a) less than 50 kPa·s at 20°C (at D = 10 s⁻¹). -1 (The shear rate measurement), wherein not all exponents a to e can be 0, preferably (a+b)>0.

[0120] The viscosity of component a2) refers to the viscosity of a single component a2) or a mixture of components a2). The latter includes mixtures present at 20°C with a viscosity of D = 10s. - The viscosity at a shear rate of 1 can exceed 50 kPa·s for independent components (a2), such as resin components or gums (gum) containing Q and / or T units (a2).

[0121] In equation (I), the sum of exponents should be expressed based on the number-average molecular weight M. n Average degree of polymerization Pn .

[0122] In equation (I):

[0123] M=R 3 SiO 1 / 2 , or M*

[0124] D = R 2SiO 2 / 2 , or D*

[0125] T = RSiO 3 / 2 , or T*

[0126] Q = SiO 4 / 2 ,

[0127] Divalent group R 2 It is a bridging group between the above silanoxy groups, preferably an optionally substituted divalent hydrocarbon group, such as an optionally substituted alkenyl group having, for example, 2-10 carbon atoms, or an optionally substituted aromatic group (e.g., arylene group), which is bonded from its carbon atom to a silicon atom, and

[0128] Each R can be the same or different, and each is an organic group, preferably selected from optionally substituted alkyl groups having up to 12 carbon atoms or optionally substituted aryl groups having up to 12 carbon atoms. The groups R are free from aliphatic unsaturation.

[0129] in

[0130] M*=R 1 p R 3 -p SiO 1 / 2 ,

[0131] D*=R 1 q R 2 -q SiO 2 / 2 ,

[0132] T*=R 1 SiO 3 / 2 ,

[0133] in

[0134] p = 0-3, preferably 1-3.

[0135] q = 1 - 2, and

[0136] R 1 As defined above.

[0137] R is preferably selected from positive-C1-C 12 - Iso-C3-C12- or tert-C4-C12-alkyl, alkoxyalkyl, C5-C 12 -Cycloalkyl or C6-C 12 -aryl, alkylaryl (the group may be additionally substituted by one or more O-, Cl-, CN- or F- atoms) or poly(C2–C4)-alkylene ethers having up to 500 alkylene oxygen units, wherein the group R is free from aliphatic unsaturation.

[0138] Suitable examples of monovalent hydrocarbon groups include alkyl groups, preferably such as CH3-, CH3CH2-, (CH3)2CH-, and C8H. 17 -and C 10 H 21 - and alicyclic groups such as cyclohexylethyl, aryl such as phenyl, tolyl, xylyl, aralkyl such as benzyl, 2-phenylethyl, and 2-phenylpropyl. Preferred monovalent haloalkyl groups have the formula C n F 2n+1 CH2CH2-, where n has a value of 1-10, for example CF3CH2CH2-, C4F9CH2CH2-, C6F 13 CH2CH2-, C2F5–O(CF2–CF2–O) 1-10 CF2–、F(CF(CF3)–CF2–O) 1-5 –(CF2) 0-2 –, C3F7–OCF(CF3)–, and C3F7–OCF(CF3)–CF2–OCF(CF3)–.

[0139] In the polyorganosiloxane (a2) of the curable organosilicon composition of the present invention, the preferred group of R is selected from methyl, phenyl, 3,3,3-trifluoropropyl, and the most preferred group of R is methyl.

[0140] R 1 Preferably selected from unsaturated groups, which include groups containing C=C- groups (alkenyl groups), for example: n-C2-C 14 -、Other-C3-C 14 -or Uncle-C4-C 14 -Alkenyl or C6-C 14 - Cyclic alkenyl, C6-C 14 -cycloalkenyl, C8-C 14 -Alkenylaryl, cycloalkenylalkyl, vinyl, allyl, methylallyl, 3-butenyl, 5-hexenyl, 7-octenyl, ethylidenenorbornel, styryl, vinylphenethyl, norbornelylethyl, limonenyl (optionally substituted with one or more O- or F atoms), or a group containing a C- group (alkynyl) that optionally contains one or more O- or F atoms.

[0141] The alkenyl group is preferably attached to the terminal silicon atom; the olefinic functional group is located at the end of the alkenyl group of the higher alkenyl group, because α-,ω-dienes used to prepare alkenylsiloxanes are more readily available.

[0142] R 1 The preferred functional groups are vinyl, allyl, 5-hexenyl, cyclohexenyl, limonenyl, styrene, and vinylphenylethyl, with the most preferred functional group being R. 1 It is vinyl.

[0143] Group R 2 This includes, for example, divalent aliphatic or aromatic n-, iso-, tert-, or cycloalkylene groups having up to 14 carbon atoms, arylene groups, or alkylene groups. R 2 This forms a bridging element between two siloxy units. R 2 The content of the radical group does not exceed 30 mol% of all silanoxy units, preferably not more than 20 mol%. R is preferred. 2 No such substance exists. A suitable divalent hydrocarbon group R. 2 Preferred examples include any alkylene residues, preferably such as -CH2-, -CH2CH2-, -CH2(CH3)CH-, -(CH2)4-, -CH2CH(CH3)CH2-, -(CH2)6-, -(CH2)8-, and -(CH2). 18 -; cycloalkylene groups, such as cyclohexene; aryl groups, such as phenylene; xylene and alkyl groups, such as benzylene, i.e., –CH2CH2–C6H4–, CH2CH2–, –C6H4CH2–. Preferred groups are α,ω-ethylene, α,ω-hexene, 1,4-phenylene, or 1,4-ethylphenylene.

[0144] Further examples include divalent haloalkyl groups R 2 For example, any divalent hydrocarbon group R in which one or more hydrogen atoms have been replaced by halogens such as fluorine, chlorine, or bromine. 2 Preferred divalent haloalkanes have the formula –CH2CH2(CF2). 1-10 CH2CH2–, such as –CH2CH2CF2CF2CH2CH2–, or other examples of suitable divalent hydrocarbon ethers and halohydrocarbon ethers, including –CH2CH2OCH2CH2–, –C6H4-O-C6H4–, –CH2CH2CF2OCF2CH2CH2– and –CH2CH2OCH2CH2CH2–.

[0145] As including R, R 1 and / or R 2 The polymer of component a2) is, for example, an alkenyl-dimethylsiloxy or trimethylsiloxy-terminated polydimethylsiloxane, which may contain other siloxane units besides alkenyl-dimethylsiloxy, such as poly(dimethyl-co-diphenyl)siloxane.

[0146] The broad component a2) of the curable organosilicon composition of the present invention may contain two or more oxygen and / or divalent groups R. 2Any polyorganosiloxane compound with silicon atoms bonded to it, wherein silicon is bonded to 0-3 monovalent groups per silicon atom, provided that the polyorganosiloxane compound contains at least two silicon-bonded unsaturated hydrocarbon residues, including alkenyl and yneyl groups, preferably, for example, alkenyl groups.

[0147] Having groups R and / or R 1 The siloxane units M, M*, D, D*, T, T* can be the same or different for each silicon atom. In a preferred embodiment, the structure is...

[0148] R 1 p R 3 -p SiO(R2SiO) m1 (R 1 RSiO) n SiR 1 p R 3 -p (1)

[0149] p = 0–3, preferred option 1

[0150] m1 = 0–12000, preferably 10–6000, more preferably 100–1000

[0151] n = 0-5000, preferably 3-2000, more preferably 5-500.

[0152] A preferred polyorganosiloxane component a2) for use in 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 amounts) of T or Q type siloxy units. This means that polymer a2) is preferably a linear, flowable fluid a3), for example, of the formula:

[0153] R 1 p R 3 -p SiO(R2SiO) m1 SiR 3 -p R p 1 (1a)

[0154] Where R 1 R, p, and m1 are each defined as above.

[0155] The condition is that each molecule has at least two alkenyl groups.

[0156] The polyorganosiloxanes a2) or a3) are most preferably selected from those of formula (1a).

[0157] Preferred structures include

[0158] Vi p Me 3-p SiO(Me2SiO) 10-12000 SiMe 3-p Vi p (1b),

[0159] PhMeViSiO(Me2SiO) 10-12000 SiPhMeVi (1c),

[0160] In the group containing alkenyl polysiloxanes (a2), a second or third polysiloxane is preferably added as component (a4) and / or a5). Components (a4) and (a5), namely so-called vinyl-rich polymers, are used to modify mechanical properties and crosslinking density.

[0161] The polymers suitable for LSR (liquid silicone rubber) are selected from P n Siloxane polymers with 100 to 2000 silanoxy units, those suitable for HCR (high-consistency rubber as described below), are preferably selected from P. n Siloxane polymers consisting of 2,000 to 12,000 silane units.

[0162] Polymer a4) is selected from polymers of formulas (1d) to (1i), namely linear polyorganosiloxanes with additional alkenyl side groups (where the concentrations of T- and Q- groups are less than 0.2 mol%), or polyorganosiloxanes with higher concentrations of T- and Q- groups than the previous polymer types a2) or a3).

[0163] Polymer a4) is represented, for example, by equations 1d)-1f).

[0164] R 1 p R 3 -p (R2SiO) b1 (R 1 RSiO) b1x SiR 3 -p R p 1 (1d)

[0165] Me3SiO (Me2SiO) b1 (MeR 1 SiO) b1x SiMe3 (1e),

[0166] R 1 Me₂SiO(Me₂SiO) b1 (Me R 1 SiO) b1x SiMe2R 1 (1f),

[0167] in

[0168] b1=>0-12000

[0169] b1x = 0 - 5000

[0170] b1 + b1x => 10 – 12000

[0171] R 1 R and p are defined as above, and

[0172] R 1 =Preferred compounds include vinyl, allyl, hexenyl, cyclohexenyl, limonenyl, styrene, and vinylphenylethyl.

[0173] Furthermore, the preferred groups of R are methyl, phenyl, or 3,3,3-trifluoropropyl.

[0174] Other preferred structures of a4) are

[0175] Vi p Me 3-p SiO(Me2SiO) 10-12000 (MeViSiO) 1-4000 SiMe 3-p Vi p (1g),

[0176] Me3SiO (Me2SiO) 10-12000 (MeViSiO) 1-4000 SiMe3 (1h),

[0177] PhMeViSiO(Me2SiO) 10-12000 (MePhSiO) 1-4000 SiPhMeVi (1i) and

[0178] In the above formula, Me = methyl, Vi = vinyl, Ph = phenyl, and p = 0 to 3, preferably p = 1.

[0179] The third component of polymer a2), namely branched polymer a5), preferably selected from those of formula (Ia), wherein the polyorganosiloxane a5 containing an alkenyl group has a T=RSiO content of more than 0.2 mol% 3 / 2 Or Q = SiO 4 / 2 unit.

[0180] (M 0.4-4 D 0-1000 T 0-50 Q 0-1 ) 1-1000 (Ia)

[0181] in

[0182] M=R 3 SiO 1 / 2 , or M*

[0183] D=R2SiO 2 / 2 , or D*

[0184] T = RSiO 3 / 2 , or T*

[0185] Q = SiO 4 / 2

[0186] Each as defined above,

[0187] M*, D*, and T*, as defined above, carry the unsaturated group R. 1 Based on all silanoxy units, the amount of such M*, D*, and T* units is preferably 0.001-20 mol%, more preferably 0.01-15 mol%, and most preferably 0.1-10 mol%.

[0188] The range of the sub-index is defined based on the number-average molecular weight M. n Possible average degree of polymerization P n The range.

[0189] The index relates to a suitable viscosity as defined below and describes a polymer for which no solvent is used for viscosity adjustment.

[0190] Preferred branched polyorganosiloxanes (a4) and (a5) typically have a higher concentration of unsaturated groups R. 1 Branched polymer a5) is described, for example, in US 5109095. Preferably, the branched vinyl-rich polymer a5) can be dissolved in xylene in greater than 10 wt% resin and has a D:T range of >10:1, preferably >33:1 and / or respectively.

[0191] (M:Q) = (0.5 to 4):1,

[0192] For example (M) 0.7 M* 0.05 Q) 10-500 (1j).

[0193] All these polyorganosiloxanes can be prepared by any conventional method for preparing triorganosiloxane-terminated polydiorganosiloxanes. For example, suitable hydrolyzable silanes, such as vinyldimethylchlorosilane, trimethylchlorosilane, tetrachlorosilane, methyltrichlorosilane, and dimethyldichlorosilane, or their corresponding alkoxysilanes, can be co-hydrolyzed and condensed in appropriate proportions. Other reaction routes can alternately carry out the equilibrium reaction of 1,3-divinyltetraorganosiloxanes, such as symmetrical dipinyldimethyldiphenylsiloxane or dipinyltetramethylsiloxane, which provides the end groups of the polydiorganosiloxanes, and can be balanced with suitable polydiorganosiloxanes, such as octamethylcyclotetrasiloxane, in the presence of an acidic or basic catalyst.

[0194] Vinyl-rich polymers, especially branched polymers with MQ or MDQ structures and Si-olefin or SiH groups, are particularly suitable. Such branched polymers can partially or completely replace filler component c) while still providing high mechanical reinforcement. This provides additional options for reducing viscosity and altering electrical properties.

[0195] In a preferred embodiment, the polymer component a2) in the curable silicone composition may be a mixture of polymers of formula (Ia) and / or formulas (1d) and / or (1j), wherein the average alkenyl content of the mixture is preferably less than 2 mol% of all silanoxy units of mixture a), and wherein the amount of polymer a3) is higher than that of a4) or a5).

[0196] For so-called high-viscosity rubber, the relevant silicone polymer (compound) viscosity is at 20℃ and D=10s. -1 The shear rate is 5-100 kPa·s. In the case of polydimethylsiloxane, this generally involves P with 3000-12000 silanoxy units. n value.

[0197] In a preferred embodiment of the curable liquid silicone rubber (LSR) composition, it is preferred to use it at 20°C and D = 10s. -1 Viscosities less than 1 kPa·s at shear rates; for polydimethylsiloxanes, this generally involves P < 2500 silanoxy units. n Value. In both embodiments, polydimethylsiloxanes having vinyl groups are preferred.

[0198] For this implementation scheme, the viscosity of the polyorganosiloxane (a2) is preferably at 20°C and D = 10s. -1 At shear rates of 100 to 300*10 3 mPa.s, and P n >10 to 2500.

[0199] In a preferred embodiment of an LSR composition containing polymer a2) or a mixture of, for example, 2-4 polymers (component a2), the blend is heated at 20°C and D = 10s. -1 The viscosity at the shear rate should be less than 200,000 mPa·s to ensure that the viscosity of the liquid silicone rubber composition is sufficiently low. This low viscosity is a hypothesis and is beneficial for manufacturing compositions that include reinforcing fillers and for processing these compositions in LSR injection molding processes.

[0200] The alkenyl content of component a2) can be determined by... 1H For NMR determination, see ALSmith (ed.): The Analytical Chemistry of Silicones, J. Wiley & Sons 1991 Vol. 112 pp. 356 et seq., Chemical Analysis, edited by JD. Winefordner.

[0201] In another preferred embodiment, component a2) comprises at least one of component A1) and at least one of component a2), as defined below:

[0202] A1) At least one polyorganosiloxane of formula (Ia),

[0203]

[0204] Each R is independently selected from saturated or aromatic organic groups, each R 1 Independently selected from alkenyl groups, and x ≥ 0.

[0205] A2) At least one polyorganosiloxane of formula (Ib),

[0206]

[0207] Where x, R and R 1 As defined above; R 3 Selected from R or R 1 And y≥1, and wherein the alkenyl R in preferred component A2) 1 With the alkenyl 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.

[0208] Component a2) preferred for preparing a non-curing masterbatch composition containing polyorganosiloxane a1) is again preferably selected from the linear component A1 as defined above.

[0209] Crosslinking agent component b )

[0210] In a preferred embodiment, the curable polyorganosiloxane composition is cured by a hydrosilylation reaction and further comprises one or more polyorganohydrosiloxanes (b) as crosslinking agents. In this case, the organic peroxide component (e) as a crosslinking initiator is preferably omitted.

[0211] The curable silicone composition of the present invention preferably contains a crosslinking agent component b) selected from the following: preferably containing a crosslinking agent component selected from the formula RHSiO and R2HSiO. 0.5 The concentration of those units and the SiH units is 1-100 mol% relative to all siloxane units in the polyorgano-based hydrosiloxane, wherein R is an organic group as defined above, and preferably methyl or phenyl.

[0212] Component b) is preferably at least one polyorganosiloxane having at least two Si-H groups. Suitable polyorganosiloxanes b) containing SiH units can be described in form by general formula (II).

[0213] (M 1 a2 D 1 b2 T 1 c2 Q d2 R 2 e2 ) m2 (II)

[0214] The silaneoxy unit thereon

[0215] M 1 =M (as defined above), or M**,

[0216] D 1 =D (as defined above), or D**,

[0217] T 1 =T (as defined above), or T**,

[0218] Q is as defined above, and

[0219] R and R 2 As defined above,

[0220] in

[0221] M**=HR2SiO 1 / 2 D** = HRSiO 2 / 2 T** = HSiO 3 / 2 ,

[0222] a2 = 0.01 - 10, preferred value = 2 - 5, optimal value = 2

[0223] b2 = 0-1000 (preferred) = 10-500

[0224] c2 = 0-50 Preferred = 0

[0225] d2 = 0-1, preferred option = 0 or 1, best option = 0

[0226] e2 = 0 - 3 Preferred = 0

[0227] m2 = 1-1000, preferred = 1-500, best choice = 1-20

[0228] Not all exponents "ae" can be 0; preferably, (a+b) > 0.

[0229] The condition is that at least two SiH-containing silanoxy units selected from M**, D** and T** are present in general formula (II).

[0230] Preferably, the polyorgano-based hydrosiloxane (b) has an average of at least four, preferably at least five, and even more preferably at least six silicon atoms.

[0231] Silyoyl units can be distributed in a block or random manner in the polymer chain.

[0232] The above index should be expressed as described above, based on the number-average molecular weight M. n Average degree of polymerization P n .

[0233] The range of M-, D-, T-, and Q- units present in the molecule can cover almost all values ​​for obtaining fluids, flowable polymers, liquids, and solid resins. Linear, cyclic, or branched siloxanes that are liquid at room temperature (25°C) are preferred. Optionally, these siloxanes may additionally contain trace amounts of C1-C6-alkoxy or Si-hydroxyl groups remaining from the synthesis.

[0234] The preferred structure of component b) in the curable organosilicon composition of the present invention is a siloxane of formula (2a) to (2e).

[0235] H a1 (R) 3-a1 Si(RHSiO) x (R2SiO) y (RR 1 SiO) z Si(R) 3-a1 H a1 (2a)

[0236] More specifically:

[0237] HR2SiO(R2SiO) y (RR 1 SiO)z (RHSiO) x SiR2H(2b)

[0238] HMe2SiO(Me2SiO) y (RR 1 SiO) z (MeHSiO) x SiMe2H(2c)

[0239] Me3SiO (MeHSiO) x SiMe3(2d)

[0240] {(HRSiO) v (R2SiO) w}(2e)

[0241] Where R and R 1 As defined above, R is preferably methyl and / or phenyl. 1 Preferably vinyl, and the index 'a1' is 0-1, preferably 0, and

[0242] x = 2 – 1000, preferred = 2 – 500

[0243] y = 0–650, preferred = 0–100

[0244] z = 0-65, preferred = 0

[0245] Preferably, 3 < x + y + z < 1000, more preferably 4 < x + y + z < 650.

[0246] v ranges from 2 to 7.

[0247] w is between 0 and 3.

[0248] 3≤v+w≤7.

[0249] Furthermore, resin polyorgano-based hydrosiloxanes of the following formula are possible:

[0250] {(T 1 (R) 4 O 1 / 2 ) n2} m2 (2f)

[0251] {(SiO 4 / 2} (R) 4 O 1 / 2 ) n2 (M 1 ) 0,01-10 (T 1 ) 0-50 (D 1 ) 0-1000}m2 (2g)

[0252] in

[0253] T 1 M 1 D 1 As defined above,

[0254] n2 = 0 to 3

[0255] m2 is defined above.

[0256] R 4 It is hydrogen, C1-C 25 -alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-, iso- and tert-butyl, alkylacyl groups such as acetyl, aryl, -N=CHR such as butanone oxime, alkenyl groups such as propenyl.

[0257] A preferred embodiment of the compound (2g) is provided, for example, via a monomeric to polymeric compound described by the following formula: ((Me2HSiO) 0.5 ) k SiO 4 / 2 ) 1-1000 The index k is 0.3-4. Such liquid or resin molecules may contain a significant concentration of SiOH- and / or (C1-C6)-alkoxy Si groups, up to 10 mol% relative to silicon atoms.

[0258] Specific examples of preferred suitable compounds for component b) in the curable silicone composition of the present invention include:

[0259] Me3SiO-(MeHSiO) 2-650 -SiMe3

[0260] (MeHSiO) 4-7 ,

[0261] HMe2SiO-(Me2SiO) 0-300 (MePhSiO) 0-300 (MeHSiO) 1-650 SiMe2H,

[0262] Me3SiO-(Me2SiO) 0-300 (MePhSiO) 0-300 (MeHSiO) 2-650 SiMe3

[0263] Me3SiO-(Me2SiO) 0-300 (Ph2SiO) 0-300 (MeHSiO) 2-650 SiMe3.

[0264] Component b) may be used as a single component of a polyorganosiloxane polymer or a mixture thereof.

[0265] If a higher curing rate is required, it is preferable to use some products containing HMe2SiO. 0.5 - A single-unit polyorganosiloxane (b) or homopolymer MeHSiO polymer to adjust the curing rate to a shorter time.

[0266] The viscosity of component b) at 20°C is preferably 2-1000 mPa·s, which is at D = 10 s. -1 The measurements were taken at the shear rate.

[0267] Preferably, each molecule of the crosslinking agent b) should have at least three reactive SiH groups. Additionally, so-called chain extenders with an average of >1 to 3 reactive SiH groups per molecule may also be present.

[0268] The total amount of SiH groups in component b) of the formulation is equal to the amount of unsaturated hydrocarbon residues R present in component a) and if present in b). 1 The total molar ratio is 0.7-15, preferably 0.8-8, more preferably 1.0-7, and most preferably 1.0-4.

[0269] Further preferred are polyorganosiloxanes in which the molar ratio of R2SiO:RHSiO units is >1.

[0270] The preferred R groups in the polyorganosiloxane are methyl, phenyl, and 3,3,3-trifluoropropyl. The preferred viscosity is below 1000 mPa·s at 20°C, more preferably below 400 mPa·s (at D = 10 s). -1 (Measured at the shear rate).

[0271] Component c) Reinforcing filler

[0272] The curable silicone composition of the present invention may include one or more preferred reinforcing filler components, comprising one or more reinforcing silica or resins, preferably silicone resins. Preferably, the curable silicone composition includes one or more preferred reinforcing filler components.

[0273] Preferably, they are selected from BET surfaces with a surface area of ​​50-400m². 2 / g of fumed silica.

[0274] If appropriate, fumed silica is a surface-modified reinforcing filler (c). Reinforcing filler (c) is characterized by a BET surface area of ​​50 m². 2 / g or larger, and a primary particle size <50nm. In the context of this invention, component d) is not included in the reinforcing filler c).

[0275] Preferably, these fillers are surface-hydrophobic. If component c) is used, based on 100 parts by weight of component a), i.e., polyorganosiloxane a2), the amount is preferably up to 100 parts by weight, preferably 0-60 parts by weight, even more preferably 0-50 parts by weight, even more preferably 5-30 parts by weight.

[0276] BET has a surface area of ​​50m² 2 Fillers of / g or higher allow for the production of silicone elastomers with improved mechanical properties. From the perspectives of strength, resistivity, and flame retardancy, fumed silica is preferred, and even more preferred silica is, for example, silica with a BET surface area greater than 200m². 2 / g 300, 400 Or T30, MS7 or HS5, manufactured by processes such as Evonik (formerly Degussa), Wacker, or Cabot.

[0277] Filler c) can be treated with any suitable conventional surface treatment agent belonging to the reactive silane or siloxane family as an auxiliary additive f). Preferred silanes or siloxanes for surface treatment are, for example, silazanes in the presence of water, such as hexamethyldisilazane and / or 1,3-divinyltetramethyldisilazane, which, in a preferred embodiment, can be achieved by “in-situ” hydrophobicization of the filler surface. In other embodiments, it can also be done with other common filler treatment agents (e.g., polyorganosiloxane diols with chain lengths of 2-50 and unsaturated organic groups).

[0278] Reagents used for filler treatment can provide reaction sites for crosslinking reactions.

[0279] In a preferred embodiment of the curable liquid silicone rubber, it is preferably treated with hexaorgano-based disilazane and water and their reaction products.

[0280] Examples of commercially available silica pre-hydrophobically modified with various silanes include Aerosil R 972, R 974, R 976, or R812, or, for example, HDK 2000 or H30. The rheological properties of uncured silicone rubber compounds, i.e., their technical processing properties, can be affected by the choice of filler type, its amount, and its hydrophobic properties.

[0281] Other fillers referred to as semi-reinforced or unreinforced fillers include, for example, those with a particle size of less than 100 μm and a BET surface area of ​​<50 μm. 2 All fine particulate fillers per g are included in component f) as auxiliary additives.

[0282] Component d) One or more types of carbon black

[0283] The curable organosilicon composition according to the present invention contains one or more carbon blacks (d), which are incorporated into the curable organosilicon composition of the present invention by mixing the other components of the curable composition with the non-curable composition (i.e., carbon black masterbatch).

[0284] The amount of one or more carbon blacks (d) in the curable organosilicon composition of the present invention is 0.1–2 parts by weight, based on 100 parts of a variety of polyorganosiloxanes (a2) having one or more unsaturated groups.

[0285] More preferably, the amount of one or more carbon blacks (d) in the curable organosilicon composition of the present invention can be, for example, about 0.15-2 parts by weight, more preferably 0.2-1.5 parts by weight, and even more preferably 0.3-1 parts by weight, all based on 100 parts by weight of a polyorganosiloxane (a2) having one or more unsaturated groups.

[0286] Preferably, the curable composition of the present invention contains only one type of carbon black.

[0287] Preferably, the curable silicone composition according to the invention comprises about 0.1 to about 2.4% by weight (weight percentage), preferably about 0.3 to about 2.2% by weight, and even more preferably about 0.5 to about 2.0% by weight of one or more carbon blacks (d) based on the total weight of the curable silicone composition.

[0288] As carbon black (d), virtually all types of carbon black (e.g., acetylene black, channel black, furnace black, lampblack, or pyrolytic black) can be used. As is well known to those skilled in the art, carbon black is a paracrystalline form of carbon that typically has a high, but lower, surface area to volume ratio than activated carbon. It differs from soot in that it has a much higher surface area to volume ratio and a significantly lower (negligible and non-bioavailable) content of polycyclic aromatic hydrocarbons (PAHs).

[0289] In a preferred embodiment of the present invention, the at least one dielectric active compound d) is conductive carbon black, preferably furnace black, i.e. manufactured by furnace black process.

[0290] In a preferred embodiment, the one or more carbon blacks d) comprise at least one carbon black selected from those with a BET surface area >30 μm. 2 / g and / or average primary particle size D 50 It is conductive carbon black with a wavelength of 5 to 500 nm.

[0291] In a further preferred embodiment, 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:

[0292] • BET surface area >100-1500m² 2 / g, more preferably >100-1400m 2 / g, more preferably >100-1000m 2 / g, more preferably >250-1000m 2 / g, more preferably >500-1000m 2 / g, and / or

[0293] Primary particle size D 50 The wavelength is 5-500nm, more preferably 10-200nm, and / or

[0294] • DBP orifice volume 300-600ml / 100g, more preferably 300-550ml / 100g, even more preferably 300-400ml / 100g, and / or

[0295] • Iodine adsorption of 700-1200 mg / g, more preferably 700-1150 mg / g, even more preferably 700-1000 mg / g, even more preferably 700-900 mg / g, and / or

[0296] • pH 8-11, more preferably pH 9-11, even more preferably pH 9-10.5 and / or

[0297] • Metal content <50ppm, and / or

[0298] • Sulfur content <150ppm, and / or

[0299] • Water content <0.5wt%, and / or

[0300] • Volatile content <1 wt%, and / or

[0301] • Fine particles <125 micrometers in the granules <10wt%, and / or

[0302] • Coarse particle content: <50mg / kg, and / or

[0303] Ash content: <0.1wt%.

[0304] Preferably, the curable organosilicon composition according to the invention contains only one type of carbon black.

[0305] Commercially available carbon blacks include Printex XE2, Printex HV (Evonik), Black Pearls 2000, Vulcanox C72, Vulcanox C72 (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), CD 7087 (Columbian Chemicals), TokaBlack 5500 (TokaiCarbon), Chezacarb A (Unipetrol), etc.

[0306] The preferred carbon black is conductive carbon black sold under the trademark Ketjenblack (Akzo Nobel), especially Ketjenblack EC-300J, and conductive carbon black in granular form (CAS No. 1333-86-4).

[0307] Component d1) Other dielectric active compounds (belonging to auxiliary additives f)

[0308] In addition to one or more carbon blacks d), the curable organosilicon composition according to the present invention may optionally contain other (one or more) dielectric active compounds d1) as auxiliary additives f), which are selected from conductive or semi-conductive fillers.

[0309] Other dielectric active compounds (d1) are preferably selected from conductive or semiconductive fillers, including, for example, graphite, graphene, fullerene, carbon nanotubes, oxides, carbides, ferrites or Ti spinel, Al, Zn, Fe, Mn, Mo, Ag, Bi, Zr, Ta, B, Sr, Ba, Ca, Mg, Na, K, Si, their inorganic salts such as chlorides, sulfates, and those selected from ionic liquids and ionic polymers.

[0310] The amount of such other dielectric active compounds may be, for example, about 0-2 parts by weight, preferably 0.1-2 parts by weight, more preferably >0.15-2 parts by weight, more preferably >0.2-1.5 parts by weight, and even more preferably >0.3-1 parts by weight, all based on 100 parts by weight of a polyorganosiloxane a2 having one or more unsaturated groups.

[0311] The average diameter D of the particulate dielectric active compound50 Preferably 5-500nm, more preferably 5-200nm.

[0312] D 50 It is measured by light scattering according to ISO 22412:2008. The diameter, based on coarse particle sieve analysis, should be less than 10 wt% for particles larger than 125 μm, especially in granular materials.

[0313] Other suitable compounds as component d1) are ionic liquids and ionic polymers selected from compounds containing ammonium, phosphonium, carboxylate, phosphate or sulfonate groups and counterions such as cations or anions.

[0314] Other preferred dielectric active components (d1) are selected from titanium dioxide (TiO2), iron and zinc oxides (especially spinel and ferrite). However, in a preferred embodiment, the use of ZnO is not preferred.

[0315] The preferred BET surface area of ​​titanium dioxide as the dielectric active component (d1) is in the range of 35-300 μm. 2 / g and particle size less than 30nm. For example, gas-phase TiO2 P25 (Degussa Evonik) has a number-average primary particle size of 21nm and a particle size of 50nm. 2 / g BET surface. Another type of TiO2 is precipitated anatase (Kronos 7050), which has, for example, about 225 μm. 2 / g BET surface area and 15nm number-average primary particle / crystal size.

[0316] Using TiO2 or Fe3O4 as component d1) also helps to enhance the flame retardant effect achieved by crosslinking catalysts based on Pt compounds as component e).

[0317] In a preferred embodiment of the invention, the curable organosilicon composition contains only one or more carbon blacks (d) as dielectric active compounds.

[0318] However, if any dielectric active compound d1) other than carbon black d) is present in the curable silicone composition according to the invention, its amount may be from 0.01 wt% to 1.96 wt%, preferably 0.05-1.90 wt%, more preferably 0.1-1.8 wt%, more preferably 0.15-1.7 wt%, more preferably 0.2-1.5 wt%, more preferably 0.3-1.0 wt%, more preferably 0.3-0.7 wt%, relative to the total weight of the curable silicone composition.

[0319] According to the present invention, by appropriately adjusting the amount and type of dielectric active compound d (one or more carbon blacks) and d1 (dielectric active compounds other than carbon black) (preferably only d) the cured organosilicon composition particularly possesses electrical properties that make it suitable for use as an insulator in high voltage direct current (HVDC) applications, especially giving the insulator a volume resistivity greater than 1*10⁻⁶ in an electric field of 10 kV / mm to 30 kV / mm in the range of 25-90°C. 11 Ohm*cm, preferably greater than 1*10 12 Ohm*cm, more preferably greater than 1*10 13 Ohm*cm, and even more preferably greater than 1*10 14 Ohm*cm, and preferably at most 1*10 16 Ohm*cm. Furthermore, according to the present invention, the amount and type of dielectric active compounds d) and d1) (preferably only d) are appropriately adjusted so that the cured silicone composition of the present invention exhibits temperature dependence of volume resistivity in the range of 25-90°C under an electric field of 10kV / mm to 30kV / mm, such that the ratio of maximum volume resistivity to minimum volume resistivity is <10, and / or the volume resistivity in the range of 25-90°C under an electric field of 10kV / mm to 30kV / mm is preferably greater than 1*10. 11 Ohm*cm, more preferably greater than 1*10 13 Ohm*cm, more preferably greater than 1*10 16 Ohm*cm, and even more preferably greater than 1*10 17 Ohm*cm, preferably up to 1*10 18 Ohm*cm. Furthermore, the cured silicone composition of the present invention preferably has a volume resistivity of 1*10⁻¹⁰ in the range of 25-90°C and under an electric field of 10kV / mm to 30kV / mm. 11 and 1*10 18 Between Ohm*cm, preferably between 1*10 13 and 1*10 18 Between Ohm*cm, more preferably between 1*10 14 and 1*10 18 The value is between 1 Ohm*cm, and the optimal value is between 1*10. 16 and 1*10 18 The preferred curing silicone composition is one or more carbon blacks, with a carbon black content of 1.0-2.0 wt% based on the total weight of the curable composition, and a volume resistivity between 1*10⁻⁶ at an electric field of 10 kV / mm to 30 kV / mm in the range of 25-90°C. 16 and 1*10 18Between Ohm*cm. The volume resistivity of the cured silicone composition was measured according to DIN EN 62631-3-1 using a test piece with an effective diameter of 31 mm and a thickness of 1 mm.

[0320] Measurements were performed at room temperature unless otherwise specified. The electrodes were made of brass and polished before use. Conductive coatings (such as silver ink) were not used because the silicone provides good contact with the electrodes. For polarization, a PNChp-30000-2 DC power supply from Heinzinger was used, with a maximum voltage of 30 kV / mm and a maximum current of 2 mA. The minimum detectable current was 1 fA (nanoampere). The optimal resolution in the test setup was 10 fA.

[0321] Method for incorporating a non-curing silicone composition (masterbatch) as defined above into a curing silicone composition according to the present invention.

[0322] Carbon black component d) is suitable to be incorporated into the curable silicone composition of the invention in the form of a non-curable silicone composition according to the invention, i.e., as a masterbatch, for example, using a dissolving mixer.

[0323] Typically, in the case of the hydrosilaneation / addition curable silicone composition according to the invention, it is prepared by producing two parts, one part comprising a polyorganosiloxane (a2) and carbon black masterbatch (i.e., the non-curable silicone composition according to the invention), optional filler component (c), hydrosilaneation catalyst (e), and optional auxiliary additive (f), and the other part comprising a polyorganosiloxane (b), optional filler component (c), and optional auxiliary additive (f). For curing, these parts are mixed and subsequently heated to obtain the cured silicone composition according to the invention.

[0324] Component e) Crosslinking catalyst

[0325] In a preferred embodiment, the curing catalyst is selected from compounds that can be cured by a hydrosilylation reaction, ranging from 0 to 1000 ppm (relative to the sum of the weights of components a) to d).

[0326] The curing catalyst e) used as the hydrogenation silylation catalyst in this invention is selected from metals or metal compounds of Pt, Pd, Rh, Co, Ni, Ir or Ru.

[0327] The curable organosilicon composition of the present invention preferably contains platinum or at least one platinum compound (e), which acts as a curing catalyst if component (b) SiH polyorganosiloxane is present, and is optionally necessary for the desired flame retardancy.

[0328] Possible Pt components (e) may be selected from, for example, common platinum catalyst components, such as those selected from organoplasmic compounds, platinum salts, or metals, with or without a solid support such as activated carbon, carbon, or silica powder, as taught in, for example, US 3,159,601; US ​​3,159,662; US 3,419,593; US 3,715,334; US 3,775,452 and US 3,814,730.

[0329] The curing reaction via hydrogenation silanization can, of course, be initiated by other metals or metal compounds known to those skilled in the art. Other metals may include Pd, Rh, Co, Ni, Ir, or Ru.

[0330] Suitable platinum compounds also include photoactivated catalysts, including (η-diene)-(σ-aryl)-platinum complexes (see, for example, US 4,530,879 or US 2003 / 0199603), η 5 Cyclopentadienyl platinum complexes or complexes with optionally substituted cyclopentadienyl ligands having σ-bonded ligands (preferably σ-bonded alkyl or aryl ligands). Other platinum compounds whose reactivity can be controlled, for example, by using azodicarboxylic acids (such as those disclosed in US 4640939) or diketoesters can also be used. Furthermore, photoactivated platinum compounds that can be used are selected from those having ligands selected from diketones. Other Pt catalysts are mentioned, for example, in US 3715334 or US 3419593, EP 1 672 031 A1, and Lewis, Colborn, Grade, Bryant, Sumpter, and Scott in Organometallics, 1995, 14, 2202-2213, all of which are incorporated herein by reference.

[0331] If component e) is used in the hydrosilylation reaction of the curable organosilicon composition of the present invention, it acts as a catalyst compound that catalyzes the reaction of the silicon-bonded hydrogen atoms of component b) with the silicon-bonded olefin substituents of component a). The metal or organometallic compound can be any catalytically active metal, and is typically a catalytically active component containing a platinum group metal. Preferably, the metal of component e) is any platinum complex compound.

[0332] Typical platinum-containing catalyst components in the curable polyorganosiloxane compositions of the present invention are any form of platinum (O), (II), or (IV) compound capable of forming complexes with phosphites. Preferred complexes are Pt-(O)-alkenyl complexes, such as alkenyl, cycloalkenyl, and alkenyl siloxanes such as vinylsiloxanes, because they are readily dispersed in polyorganosiloxane compositions.

[0333] A particularly useful form of platinum complex is the Pt(0)-complex with aliphatic unsaturated organosilicon compounds (e.g., 1,3-divinyltetramethyldisiloxane) (vinyl-M2 or Karstedt catalyst), as disclosed in US 3,419,593, which is incorporated herein by reference, with cyclohexene-Pt, cyclooctadiene-Pt, and tetravinyltetramethylcyclotetrasiloxane (vinyl-D4) being particularly preferred. Such catalysts exhibit optimal dispersibility in the curable organosilicon compositions of the present invention.

[0334] Pt(0)-olefin complexes, for example, in 1,3-divinyltetramethyldisiloxane (M... Vi 2) In the presence of basic compounds such as alkali metal carbonates or hydroxides, hexachloroplatinic acid or other platinum chlorides are prepared by alcohol reduction (the hydrazine reduction products of Pt(IV) and Pt(II) can also be used).

[0335] The amount of the platinum-containing catalyst component used as a flame retardant additive in the curable organosilicon composition of the present invention is subject to two limitations.

[0336] On the one hand, the amount should provide the required flame retardancy; on the other hand, due to cost reasons and the need to balance reactivity and pot life under storage, the amount should be as low as possible.

[0337] Therefore, it is preferable to provide a curable polyorganosiloxane composition wherein the platinum concentration is 1-120 ppm, preferably 1-100 ppm, more preferably 1-70 ppm, and even more preferably 1-38 ppm (based on the metal relative to components a) to f).

[0338] Typically, the reactivity of Pt catalysts must be controlled in terms of curing time by means of so-called inhibitors (defined as auxiliary additives under component f).

[0339] In another embodiment of the invention, the curing catalyst e) is selected from 0.1-2 wt% of an organic peroxide relative to a) to f), wherein such organic peroxide is selected from substituted or unsubstituted dialkyl-, alkylaryl-, or diaryl-peroxides.

[0340] Suitable peroxides are those commonly used in high-consistency silicone rubbers (HCR, HV, HTV), selected from dialkyl-, alkylaryl, and diaryl peroxides. Preferred peroxides are all peroxides having a half-life that allows mixtures of the curable polyorganosiloxane compositions of the present invention containing that peroxide to be stored at 25°C for at least 10 days, preferably more than 30 days, without premature curing. Premature curing means premature curing, i.e., an increase in Mooney viscosity exceeding 20 Mooney units, or gelation, i.e., an increase in the loss modulus G” measured in a rheometer to the level of the elastic modulus G′.

[0341] The preferred reactivity of the peroxide allows the curing of polymethyl or polymethylvinylsiloxane to occur in less than 15 minutes at temperatures below 180°C.

[0342] Preferred examples of such curing agents are organic peroxides, such as dibenzoyl peroxide, di-o-methyl or p-methylbenzoyl hydroperoxide, di-2,3-, di-2,4- or di-2,5-dichlorobenzoyl peroxide, di-tert-butyl peroxide, and peroxides for pressure transfer or injection molding, such as butyl perbenzoate, dicumyl peroxide, α,α'-di-(tert-butylperoxy)diisopropylbenzene, and 2,5-bis-(tert-butylperoxy)-2,5-dimethylhexane.

[0343] HCR silicone compositions can also be cured using component b) and a hydrogen silane catalyst. From a flame retardancy perspective, it is preferable to use a Pt hydrogen silane catalyst as a dual additive (not only as a crosslinking catalyst, but also to improve flame retardancy).

[0344] Component f) Auxiliary additives

[0345] Optionally, the curable silicone composition according to the invention may include auxiliary additives f), which are preferably selected from pigments, adhesion promoters, plasticizers, flame retardant additives, solvents, diluents, processing aids for filler treatment, and other dielectric active compounds d1 as described above.

[0346] Adhesion promoter

[0347] In one embodiment, the curable silicone composition according to the invention comprises at least one adhesion promoter. These compounds improve the ability of the compositions of the invention to adhere to several substrate surfaces, such as metal, thermoplastic or rigid plastic surfaces, glass, natural or synthetic textile fibers or other ceramic substrates.

[0348] The adhesion promoter is preferably used in an amount of 0.1-2 wt% relative to component a). If some crosslinking agents b) have substituents such as aryl, acryloyl, methacryloyl, or epoxy groups in addition to the SiH unit, they can act as adhesion promoters. Furthermore, some nitrogen compounds f) can act as adhesion promoters, especially if alkoxysilyl groups are present.

[0349] A preferred type of adhesion promoter is selected from silanes of formula (3).

[0350] X-(CR 9 2) e -Y-(CH2) e SiR 9 d (OR 8 ) 3-d (3)

[0351] in

[0352] X is selected from halogens, pseudohalogens, unsaturated aliphatic groups having up to 14 carbon atoms, epoxy-containing aliphatic groups having up to 14 carbon atoms, groups containing cyanurate esters, and groups containing isocyanurate esters.

[0353] Y is selected from single bonds, and from heteroatomic groups selected from –COO–, –O–, –S–, –CONH–, –HN–CO–NH–.

[0354] R 9 Selected from hydrogen and R as defined above,

[0355] R 8 It is a C1–C8 alkyl group, ranging from 0, 1 to 8, and can be the same or different.

[0356] d ranges from 0, 1 to 2.

[0357] Preferred examples of adhesion promoters for f) include:

[0358] γ-glycidyloxypropyltrialkoxysilane, (3,4-epoxycyclohexyl)alkyltrialkoxysilane, methacryloyloxypropyltrialkoxysilane, isocyanate-propyltrialkoxysilane, isocyanate-methyltrialkoxysilane, and vinyltrialkoxysilane.

[0359] Other optional auxiliary additives are used in amounts of 0-15 pt.wt. per 100 pt.wt. of component a). Auxiliary or conventional additives include, for example, plasticizers, release oils, hydrophobic oils (such as polydimethylsiloxane), and polydiphenyl dimethylsiloxane oil with a viscosity preferably of 0.001-10 Pa·s at 20°C.

[0360] Furthermore, if it is particularly present as an outer layer, it may be necessary to color it with inorganic or organic pigments having a minimal amount of pigment, as these pigments typically weaken or impair mechanical or electrical properties. Additional release agents or flow improvers may also be used, examples being fatty acid derivatives or fatty alcohol derivatives, and fluoroalkyl surfactants. Compounds advantageously used in this invention are those that rapidly separate and migrate to the surface. Stability after exposure to hot air can be improved, for example, using known hot air stabilizers such as Fe-, Mn-, Ti-, Ce-, or La- compounds, and organic salts, preferably their organic complexes, such as diketoates or triketoates.

[0361] In addition, auxiliary additives f) may include hydrophobic agents used to treat reinforcing filler components c), such as organosilanols or organosilazanes and water, such as trimethylsilanol, vinyl dimethylsilanol, hexamethyldisilazane, and 1,3-divinyltetramethyldisilazane.

[0362] The auxiliary additives may also include so-called inhibitors for controlling the hydrosilylation crosslinking reaction. When the curable silicone composition contains all the components for the hydrosilylation reaction, namely a1) the alkenyl group, b) the SiH group, and platinum or compounds thereof, the reaction rate should preferably be controlled by an inhibitor to avoid premature curing of the reactive curable silicone composition at 25°C before the desired curing and / or molding steps for manufacturing coatings or molded articles. Inhibitors for the hydrosilylation reaction are known. Examples of advantageous inhibitors include, for example, vinylsiloxanes, 1,3-divinyltetramethyldisiloxane, or tetravinyltetramethylcyclotetrasiloxane. Other known inhibitors may also be used, such as alkynyl alcohols, like ethynylcyclohexanol, 3-methylbutynol, dimethyl maleate, alkyl-, aryl- or alkylaryl-phosphine, alkyl-, aryl- or alkylaryl phosphites, or alkyl-, aryl-amines, which, according to the invention, interact with those Pt-compounds to affect the hydrosilylation activity of the catalyst, thereby providing an excellent balance between storage stability and reactivity at elevated temperatures during curing.

[0363] To improve flame retardancy, nitrogen or phosphorus compounds that enhance the effect of Pt compounds are preferred. These flame retardant additives are selected from azo, hydrazine, triazole, tetraazole, guanidine, melamine, urea, or phosphite derivatives.

[0364] Solvents and / or diluents

[0365] In one particular embodiment, the curable silicone composition according to the invention is suitable for spray application. In this case, the curable silicone composition according to the invention may contain a solvent and / or a diluent. Such a solvent and / or diluent may be selected from, for example, siloxanes, organic solvents such as hydrocarbon solvents, ester-based solvents, and alcohol-based solvents.

[0366] Other additive fillers or pigments:

[0367] Additional additives may also include other fillers. These other fillers are different from dielectric active compounds d) or d1). Their use should not impair the effect of components d) or d1). Additional pigments or fillers should only be incorporated if they do not interact with or impair or delay the dielectric properties of components d) or d1).

[0368] Therefore, incremental fillers or pigments may be used, as they may have effects directly similar to or interact with component d). Therefore, if used, the concentration must be less than 1% by weight, preferably less than 0.1% by weight.

[0369] Typical organic pigments are selected from, for example, perylene and phthalocyanine organic pigments.

[0370] The filler material can be selected from silicates, diatomaceous earth, ground silica, quartz, mica, amorphous carbonates, borates, hydroxides / oxides, and oxides of Al, Ca, Mg, Fe, and Zn, with a particle size higher than that of component d). These ground fillers and pigments are preferably semi-reinforced or unreinforced fillers or pigments with a particle size between 1 and 100 μm and a BET surface area <30 μm. 2 / g.

[0371] Furthermore, since many of these fillers are typically abrasive to metal nozzles and surfaces in injection molding machines or molds, most of these fillers are omitted for several other reasons. Part of the inventive concept is that the concentration of abrasive fillers should be as low as possible to increase the lifespan of the nozzles and molds themselves in the injection molding machine. Such abrasive fillers can be tolerated if they are not abrasive to the metal surfaces of the nozzle during injection molding, but in principle, their use should be avoided, or less than 3 pt.wt per 100 parts by weight of component a). Abrasive fillers such as ground quartz or cristobalite powder or diatomaceous earth are generally less preferred.

[0372] All curable silicone compositions of the present invention can be cured by any process known in silicone technology and related processes for manufacturing molded articles, including coated articles obtained by spraying articles with the curable silicone compositions of the present invention. The material to be cured by the curable silicone compositions of the present invention is an elastomer, preferably used to manufacture insulators for high-voltage direct current applications. Preferably, the curable silicone compositions of the present invention are formed and cured before cable joints or terminals are assembled with cables, but typically the curing step can be performed at any point in the process chain of assembling cable accessories; that is, curing and molding cannot occur simultaneously.

[0373] The present invention also relates to a method for manufacturing an insulator suitable for high-voltage applications, wherein the curable silicone composition of the present invention is shaped by extrusion via a nozzle or by a die, and the shaped composition is cured by heat or light to form a shaped insulator. This method is 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 materials may be silicone, rubber, or thermoplastic materials, differing at least in their physical properties and the ratios and / or concentrations of individual components a) to f).

[0374] The cured silicone composition of the present invention can be used on its own as an insulating material, but is preferably used in combination with other materials well known in HVDC cable accessory design. For example, cable joints or cable terminations typically have a multi-layer design, wherein at least one of the materials providing high conductivity is part of the joint as a shielding material, such as having a volume resistivity of less than 1×10⁻⁶. 4 Conductive EPDM, conductive silicone rubber, or conductive thermoplastic at ohm*cm. Some parts of such cable accessories can be in the form of tubular or tubular flares, and therefore can be manufactured by extrusion processes.

[0375] The final insulator typically requires a more complex assembly of two to four different materials and is therefore manufactured by assembling extruded and molded parts, sometimes by casting a low-viscosity silicone rubber to apply the final outer layer as an encapsulation, especially with the help of an optional open mold cavity for joints with large volumes.

[0376] The curable silicone composition of the present invention is preferably used as a curable composition for high voltage direct current applications, and is also preferably used in the manufacture of cable joints, sheaths, sleeves, fittings, cable accessories, and cable end caps.

[0377] The cured silicone composition of the present invention is particularly used in the manufacture of cable joints intended to seal the cable ends of one or more cables having thermoplastic polyolefin or rubber cable insulation, wherein the cable joint seals the cable ends of one or more cables having thermoplastic polyolefin or rubber cable insulation.

[0378] The present invention also relates to a method for manufacturing cable joints, comprising step A1) providing at least one conductive molded silicone composition that is different from and optionally cured according to the silicone composition of the present invention, and B1) encapsulating the composition of step A1) in a mold with the silicone composition of the present invention to form and cure the cable joint or cable end cap.

[0379] The present invention also relates to a method for sealing and / or insulating connected or closed cable ends by using a cable connector as defined above, comprising the following steps:

[0380] j) Provide insulated wires and bare wires or connectors with thermoplastic or elastomer multilayer sheaths suitable for DC insulation.

[0381] In the case of a mechanical extension joint, bare wires or connected wires are encapsulated by placing a tubular pre-molded and cured cable joint hole on the surface of the insulating sheath of the joint, in such a way that the overlap between the molded silicone cable joint and the sheath on the wire insulation layer reaches approximately greater than 0.5 cm. Thus, the silicone cable joint seals the insulation layer of the insulated wire sheath through the mechanical pressure of the relaxed joint, thereby forming an encapsulating insulation layer also used for bare wires and connectors.

[0382] This assembly process, the sealing step of one or more insulated cables, can be carried out by stretching the cable joint or cable end cap with the help of compressed air or by widening the tubular hole with the help of bracket-shaped plastic or metal tools, or by keeping the joint in an extended shape and relaxing it like a shrink tube under heat.

[0383] Another method according to the invention includes using an optional transparent form, and after encapsulating one or more cables, beginning on-site curing of all materials at a temperature of 0 to 200°C or with the aid of light and a photo-activated curing catalyst (e).

[0384] Compared with cured organosilicon compositions prepared using conventional non-extruded carbon black masterbatches, the inventive organosilicon compositions cured according to the present invention have unique electrical properties.

[0385] In another embodiment of the invention, it relates to a curable organosilicon composition comprising:

[0386] a) 100 pt.wt. of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2),

[0387] b) A crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes, in the form of 0-100 pt.wt., preferably >0 to 100 pt.wt.

[0388] c) One or more filler components, preferably >0 to 100 pt.wt., comprising one or more reinforcing silica or resins, ranging from 0 to 100 pt.wt.

[0389] d) One or more types of carbon black with a content greater than 2 pt.wt., preferably 4 pt.wt.-12 pt.wt.

[0390] e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and

[0391] f) One or more auxiliary additives, 0–50 pt.wt.

[0392] Based on the total weight of the curable silicone composition, this curable silicone composition preferably contains more than 2.4 wt%, preferably 3-10 wt%, of one or more types of carbon black (d).

[0393] These high carbon black-loaded curable compositions can be cured into generally conductive and thermally conductive silicone compositions and can be used in applications where conductive and / or thermally conductive silicone rubber is required, such as for the manufacture of connectors, conductive films, electrode materials, and thermal radiation materials.

[0394] Preferred embodiments of the present invention

[0395] The following shows a preferred embodiment of the present invention.

[0396] 1. A method for manufacturing a non-curing organosilicon composition comprising carbon black, the method comprising extruding one or more polyorganosiloxanes (a1) together with one or more carbon blacks (d).

[0397] 2. According to the method of the foregoing embodiment, the total viscosity of the one or more polyorganosiloxanes (a1) is less than 100, preferably 1-100 Pa·s (at 20°C with D=10s). -1 (Shear rate measurement).

[0398] 3. The method according to any of the foregoing embodiments, wherein the polyorganosiloxane (a1) is selected from polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups.

[0399] 4. The method according to any of the foregoing embodiments, wherein the polyorganosiloxane (a1) has an organic substituent R selected from: optionally substituted alkyl such as alkyl and haloalkyl, optionally substituted aryl such as phenyl, and has one or more substituents R selected from alkenyl such as vinyl. 1 And has an average degree of polymerization P of 100 to 12,000 silanoxy units. n .

[0400] 5. The method according to any of the foregoing embodiments, wherein the extrusion is performed using an extruder, such as a multi-screw extruder, preferably a twin-screw extruder, and more preferably a co-rotating twin-screw extruder.

[0401] 6. The method according to any of the foregoing embodiments, wherein the extrusion is carried out at an extrusion material temperature of room temperature (25°C) to 250°C, preferably in the range of 50°C to 200°C, and more preferably in the range of 100°C to 175°C.

[0402] 7. The method according to any of the foregoing embodiments, wherein the extrusion is performed using one or more of the following conditions:

[0403] - Twin screws rotating in the same direction

[0404] - The screw diameter is in the range of 15 to 250 mm, preferably 20 to 100 mm.

[0405] - The feed rate is approximately 1 to 600 kg / h, preferably 100 to 550 kg / h, and more preferably 10 to 50 kg / h.

[0406] - The screw speed is 50 to 1200 rpm, preferably 100 to 1000 rpm.

[0407] - The temperature of the extruded material is 50 to 200°C.

[0408] The L / D ratio is 20 to 80, preferably 30 to 70 (where L is the length of the extruder and D is its diameter).

[0409] - The dwell time is 10 seconds to 10 minutes, preferably 15 seconds to 2 minutes.

[0410] -Use cylinder cooling

[0411] - Uses a segmented design with a geometry that allows for strong dispersion, utilizing screw elements.

[0412] 8. The method according to any of the foregoing embodiments, wherein the weight ratio of the one or more polyorganosiloxanes (a1) to the weight of the one or more carbon blacks (d) is 90:10 to 75:25, preferably 89:11 to 80:20.

[0413] 9. The method according to any of the foregoing embodiments, wherein only one or more polyorganosiloxanes (a1) and one or more carbon blacks (d) are extruded.

[0414] 10. A non-curing silicone composition obtained by the method defined in any of the foregoing embodiments.

[0415] 11. A non-curing silicone composition according to any of the foregoing embodiments, comprising at least 10, preferably at least 11, and even more preferably at least 12% by weight of one or more carbon blacks (d), based on the total weight of the entire silicone composition.

[0416] 12. A non-curing silicone composition according to any of the foregoing embodiments, comprising 10-25, preferably 11-24, and even more preferably 12-23% by weight of one or more carbon blacks (d), based on the total weight of the entire silicone composition.

[0417] 13. The non-curing organosilicon composition according to any of the foregoing embodiments, comprising one or more polyorganosiloxanes (a1) and one or more carbon blacks (d).

[0418] 14. A non-curable silicone composition according to any of the foregoing embodiments, wherein the one or more carbon blacks comprise at least one carbon black selected from the group with a BET surface area >30 μm. 2 / g and / or average primary particle size D 50 It is conductive carbon black with a wavelength of 5 to 500 nm.

[0419] 15. A non-curable silicone composition according to any of the foregoing embodiments, wherein 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:

[0420] • BET surface area >100-1500m² 2 / g, more preferably >100-1400m 2 / g, more preferably >100-1000m 2 / g, more preferably >250-1000m 2 / g, more preferably >500-1000m 2 / g, and / or

[0421] Particle size D 50 The wavelength is 5-500nm, more preferably 10-200nm, and / or

[0422] • DBP orifice volume 300-600ml / 100g, more preferably 300-550ml / 100g, even more preferably 300-400ml / 100g, and / or

[0423] • Iodine adsorption of 700-1200 mg / g, more preferably 700-1150 mg / g, even more preferably 700-1000 mg / g, even more preferably 700-900 mg / g, and / or

[0424] • pH 8-11, more preferably pH 9-11, even more preferably pH 9-10.5 and / or

[0425] • Metal content <50ppm, and / or

[0426] • Sulfur content <150ppm, and / or

[0427] • Water content <0.5wt%, and / or

[0428] • Volatile content <1 wt%, and / or

[0429] • Fine particles <125 micrometers in the granules <10wt%, and / or

[0430] • Coarse particle content: <50mg / kg, and / or

[0431] Ash content: <0.1wt%.

[0432] 16. The non-curable silicone composition according to any of the foregoing embodiments, wherein the percentage of particles smaller than 10 μm is greater than 70%, preferably greater than 80%, even more preferably greater than 90%, and / or the percentage of particles larger than 10 μm is less than 30%, preferably less than 20%, even more preferably less than 10%, even more preferably less than 5%, as determined by dynamic light scattering.

[0433] 17. A non-curing silicone composition according to any of the foregoing embodiments, wherein Dn is a particle size distribution based on the number of particles in the non-curing silicone composition. 50 Preferably less than 7μm, more preferably less than 5μm, and most preferably less than 3μm.

[0434] 18. A non-curing silicone composition according to any of the foregoing embodiments, wherein the particle size distribution Dn based on the number of particles in the non-curing silicone composition 90 Preferably less than 15 μm, more preferably less than 10 μm, even more preferably less than 8 μm, and most preferably less than 5 μm.

[0435] 19. Use of the non-curing silicone composition according to any of the foregoing embodiments for the manufacture of a curing silicone composition.

[0436] 20. Use of the non-curing silicone composition according to any of the foregoing embodiments as a masterbatch incorporated into a curing silicone composition.

[0437] 21. Use of the non-curing silicone composition according to any of the foregoing embodiments in high voltage direct current applications.

[0438] 22. A curable silicone composition comprising a non-curable silicone composition according to any of the foregoing embodiments.

[0439] 23. The curable silicone composition according to embodiment 22 above, comprising:

[0440] a) 100 pt.wt. of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2),

[0441] b) 0–100 pt.wt. of a crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes.

[0442] c) One or more filler components, ranging from 0 to 100 pt.wt, comprising one or more reinforcing silica or resins.

[0443] d) 0.1–3 pt.wt. of one or more types of carbon black,

[0444] e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and

[0445] f) One or more auxiliary additives, 0–50 pt.wt.

[0446] 24. A curable silicone composition according to any one of embodiments 22 or 23 above, comprising 0.1-2.4 wt%, preferably 0.2-2.4 wt%, more preferably 0.5-2.2 wt%, even more preferably 1.0-2.0 wt%, and even more preferably 1.3-1.8 wt% of one or more carbon black (d), based on the total weight of the curable silicone composition.

[0447] 25. A cured silicone composition obtained by curing a curable silicone composition according to any one of the preceding embodiments 22-24.

[0448] 26. The cured silicone composition according to embodiment 25, in the PEA charge movement map measured according to the method described in the examples, the movement of any charge from one or each electrode is <0.2 mm, preferably <0.3 mm.

[0449] 27. The cured silicone composition according to embodiment 25, in the PEA charge shift plot determined according to the method described in the examples, has a peak max / min shift of <0.05 mm from one or each electrode, preferably <0.1 mm.

[0450] 28. The cured silicone composition according to embodiment 25, wherein in the total charge accumulation diagram (e.g. Figure 13 In the example shown, after 5 hours, preferably after 2.5 hours, up to 20 hours of measurement time, the increase in average charge density is less than 20%, preferably less than 10% (steady state).

[0451] 29. The cured silicone composition according to embodiment 25, which, at or after 20 hours, shows a total charge accumulation diagram (e.g.) Figure 13 In the example shown, the maximum average charge density is <1.5 C / m². 3 Preferred value <1.25C / m 3 And the optimal value is <1.0C / m 3 .

[0452] 30. The cured silicone composition according to any one of embodiments 25-29, wherein the volume resistivity in the range of 25-90°C and under an electric field of 10 kV / mm to 30 kV / mm is preferably greater than 1*10. 11 Ohm*cm, more preferably greater than 1*10 13 Ohm*cm, more preferably greater than 1*10 16 Ohm*cm, and even more preferably greater than 1*10 17 Ohm*cm, with a maximum optimal value of 1*10 18 Ohm*cm.

[0453] 31. A cured silicone composition according to any one of embodiments 25 or 29, wherein the volume resistivity is between 1*10⁻⁶ in the range of 25-90°C and in an electric field of 10 kV / mm to 30 kV / mm. 11 and 1*10 19 Between Ohm*cm, preferably between 1*10 11 and 1*10 18 Between Ohm*cm, preferably between 1*10 13 and 1*10 18 Between Ohm*cm, more preferably between 1*10 14 and 1*10 18 The value is between 1 Ohm*cm, and the optimal value is between 1*10. 16 and 1*10 18 Between Ohm*cm.

[0454] 32. A cured silicone composition according to any one of embodiments 25 to 31, wherein one or more carbon blacks (d) have a carbon black content of 1.0-2.3 wt% based on the total weight of the cured silicone composition, and a volume resistivity between 1*10⁻⁶ at an electric field of 10 kV / mm to 30 kV / mm in the range of 25-90°C. 16 and 1*10 18 Between Ohm*cm.

[0455] 33. Use of the curable silicone composition according to any of the foregoing embodiments for manufacturing an insulator or field equalization component for high voltage direct current (HVDC) applications.

[0456] 34. An insulator or field equalization component for high voltage direct current applications, which is obtained by curing a curable silicone composition according to any of the foregoing embodiments.

[0457] 35. Cable accessories for high voltage direct current applications, comprising an insulator or field equalization assembly according to the foregoing embodiments.

[0458] 36. The cable accessories according to the foregoing embodiments are selected from cable joints, cable end caps and cable connectors, all of which are used in high voltage direct current applications.

[0459] 37. A cable joint according to embodiment 36, wherein the cable joint seals the end of a cable having thermoplastic polyolefin or rubber cable insulation.

[0460] 38. The curable silicone composition according to embodiment 22 above, comprising:

[0461] a) 100 pt.wt. of one or more polyorganosiloxanes having one or more unsaturated groups, preferably one or more alkenyl groups a2),

[0462] b) 0–100 pt.wt. of a crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes.

[0463] c) One or more filler components, ranging from 0 to 100 pt.wt, comprising one or more reinforcing silica or resins.

[0464] d) One or more carbon blacks greater than 2 pt.wt., preferably 4 pt.wt.–12 pt.wt.

[0465] e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and

[0466] f) One or more auxiliary additives, 0–50 pt.wt.

[0467] 39. The curable silicone composition according to embodiments 22 and 38 above, comprising more than 2.4 wt%, preferably 3-10 wt%, of one or more carbon blacks (d), based on the total weight of the curable composition.

[0468] 40. A cured silicone composition obtained by curing a curable silicone composition according to any one of the preceding embodiments 38 and 39.

[0469] 41. Use of the cured silicone composition according to embodiment 40 in the manufacture of connectors, conductive films, electrode materials, thermal radiation materials and electroactive elastomers. Example

[0470] All portions are by weight unless otherwise stated. All percentages are by weight unless otherwise stated.

[0471] Masterbatch Examples

[0472] Masterbatch Example 1: Preparation of a non-curing masterbatch containing carbon black according to the present invention

[0473] At 20℃ and D=10s -1 Vinyl-terminated linear polydimethylsiloxane (component a1) with a viscosity of 10 Pa·s at a shear rate and Ketjenblack EC 300J (Akzo) carbon black (component d) with a BET surface area of ​​800 m² / g (350 DBP pore volume ml / 100 g) and a primary particle size of 40 nm were extruded at 25 °C on a co-rotating twin-screw extruder from Leistritz (size ZSE40MAXX, L / D ratio of 52 (L is the length of the extruder and D is its diameter), and screw diameter of 41.4 mm). Throughput ranged from 100 to 175 kg / h. The temperature of the extruded material increased with increasing carbon black content, and even with cylinder cooling at very high carbon black contents, it still reached above 230 °C.

[0474] The carbon black content varies from 10% to a maximum of 23% by weight.

[0475] Table 1 – Masterbatch Examples 1-1 to 1-10

[0476]

[0477] Masterbatch Comparative Example 1: A non-curing masterbatch containing carbon black was prepared according to Example 1 of WO2016110570A1.

[0478] 100 kg was subjected to 20℃ and D = 10s. -1 A vinyl-terminated linear polydimethylsiloxane with a viscosity of 10 Pa·s at a shear rate of 12.7 kg was placed in a planetary mixer and mixed with 12.7 kg of BET at a surface area of ​​800 m². 2 Mix / g (350DBP pore volume ml / 100g) of Ketjenblack EC 300J (Akzo) carbon black with a primary particle size of 40nm. Stir the mixture in a two-blade kneader until a homogeneous mixture is obtained after 45 minutes.

[0479] The homogeneous mixture is then further dispersed on a three-roll mill for 30 minutes to obtain a dispersion of carbon black.

[0480] Table 2 - Masterbatch (Comparative Example)

[0481]

[0482] Masterbatch particle size distribution measurement

[0483] The particle size distribution of carbon black in the non-curing silicone compositions of Masterbatch Example 1 and Masterbatch Comparative Example 1 was measured in toluene solution by light scattering using a Malvern Zetasizer apparatus according to DIN EN ISO / IEC 17025, using a scattering model based on Mie theory at the lowest possible dispersion unit rotation speed (which corresponds to the lowest possible shear). Figure 14 Show the particle size distribution (quantity percentage) of the masterbatch in Comparative Example 1, and Figure 15 This shows the particle size distribution (quantity percentage) of the masterbatch from Example 1. Figure 14 and 15 A comparison of the two shows that the carbon black agglomerate particles of Masterbatch Example 1 of the present invention have a significantly smaller particle size than those of Masterbatch Comparative Example 1. While Masterbatch Example 1 of the present invention has almost no particles larger than 10 μm and particles smaller than about 1 μm, Masterbatch Comparative Example 1 has a significant portion of particles larger than 10 μm to about 100 μm and almost no particles smaller than about 3 μm. It is speculated that this different particle size distribution of the Masterbatch (non-curing silicone composition) of the present invention is surprisingly effective in improving the electronic properties of the cured silicone composition of the present invention, especially in the high-voltage direct current applications described below.

[0484] Examples of curable compositions

[0485] Example S R 1 And comparative example S R 1

[0486] Table 3 – Containing Example 1 (Ex S) R 1 ) and Comparative Example 1 (Comparative Example S) R 1 The non-curing silicone composition Chemical Composition

[0487]

[0488]

[0489]

[0490] Example S R 1 (Curing silicone composition)

[0491] The cured silicone rubber composition SR according to the present invention is prepared according to the following method. 1 :

[0492] Part A

[0493] In a dissolving mixer, 9.47 parts of carbon black paste according to Masterbatch Example 1 and 11.12 parts were mixed at 20°C for 10 seconds. -1 A mixture of 20.14 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane with a viscosity of 10 Pa·s at a shear rate of 65 Pa·s (component a2), 3.08 parts of hexamethyldisilazane (part of surface treatment agent - component c), 0.026 parts of divinyltetramethyldisilazane (part of surface treatment agent - component c), and 1.29 parts of water (additive - component f) was prepared. The mixture was then mixed with 14.25 parts of Brunauer–Emmett–Teller (BET) with a specific surface area of ​​300 m². 2 / g of fumed silica (Evonik) (Component c) was mixed and heated at 100°C for 1 hour to form a silica filler having a mixture of trimethylsilyl and vinyl dimethylsilyl groups on its surface. Water and volatile compounds generated from the surface treatment reaction were then removed from the silicone mixture at approximately 150°C under vacuum (<80 mbar) for 1 hour. The volatiles generated were then removed from the silicone mixture at approximately 150°C under vacuum (<80 mbar) for 1 hour. The mixture was then cooled and diluted with 39.13 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane with a viscosity of 10 Pa·s. Subsequently, 3.97 parts of dimethylvinylsiloxy-terminated poly(dimethylsiloxane-comethylvinylsiloxane) (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 solution containing 1.5 wt% Pt in a Pt(0) complex with tetramethyltetravinylcyclotetrasiloxane (Ashby catalyst) (component e) were added.

[0494] Part B

[0495] In a dissolving mixer, 9.47 parts of carbon black paste according to Masterbatch Example 1, 11.23 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane with a viscosity of 10 Pa·s (component a2), and 20.33 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane with a viscosity of 65 Pa·s (component a2) were mixed with 3.06 parts of hexamethyldisilazane (a portion of surface treatment agent - component c), 0.025 parts of divinyltetramethyldisilazane (a portion of surface treatment agent - component c), and 1.27 parts of water (additive - component f). This mixture was then mixed with 14.15 parts of Brunauer–Emmett–Teller (BET) with a specific surface area of ​​300 m². 2 / g of fumed silica (Evonik) (Component c) was mixed and heated at 100°C for 1 hour to form a silica filler with a surface containing a mixture of trimethylsilyl and vinyl dimethylsilyl groups. Subsequently, the volatile compounds generated from the surface treatment reaction were removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. The resulting volatiles were then removed from the silicone mixture under vacuum (<80 mbar) at approximately 150°C for 1 hour. The mixture was then cooled and diluted with 28.51 parts of dimethylvinylsiloxy-terminated polydimethylsiloxane with a viscosity of 10 Pa·s. Subsequently, 8.94 parts of the first crosslinking agent (linear poly(dimethyl)co(methylhydro)siloxane (component b) with a SiH content of 4.15 mmol / g and a viscosity of 0.035 Pas) and 5.54 parts of the second crosslinking agent (linear poly(dimethyl)co(methylhydro)siloxane (component b) with a SiH content of 2.30 mmol / g and a viscosity of 0.21 Pas) and 0.12 parts of 1-ethynyl-1-cyclohexanol (ECH) (component f) were added.

[0496] The cured silicone rubber composition according to the present invention is prepared as follows:

[0497] Mix part A and part B in a 1:1 weight ratio and cure by heating to 175°C for 10 minutes.

[0498] Comparative Example 1 ( Curable silicone composition )

[0499] Repeat SR 1 (Cureable silicone composition), the difference being that the masterbatch from Comparative Example 1 is used in the amounts given in Table 3.

[0500] Other cured compositions

[0501] Using the non-curing masterbatch carbon black paste of the present invention and the non-curing masterbatch of the present invention as described above, with different amounts of carbon black as described above for example SR 1 and comparative SR 1 The preparation of another cured composition is described above, and various electrical properties are measured as follows.

[0502] Volume resistivity

[0503] For high volume resistivity (above approximately 10) 14 The volume resistivity of the cured composition (Ω.cm) was measured according to DIN EN62631-3-1, with an effective test piece diameter of 31 mm and a thickness of 1 mm. For low volume resistivity (below approximately 10 Ω.cm), 14 (Ω.cm), volume resistivity was determined according to ISO 1853.

[0504] Method conductivity: according to the method of DIN EN 62631-3-1, and the test setup according to IEC 60093. ( High volume resistivity )

[0505] For highly insulating materials, the conductivity or volume resistivity of the cured composition sample is measured using a measuring device. The main structure of the measuring device is as follows: Figure 3 As shown, it uses a three-electrode arrangement with a guard ring. The dimensions of this arrangement are shown in the table below, where a sample thickness of d = 1 mm is used for each measurement.

[0506] surface: Figure 3 Dimensions of the middle electrode geometry:

[0507]

[0508] Further measurement parameters are as follows:

[0509] Electrode material: Brass

[0510] • Do not use silver paste as contact support

[0511] • Measure at different voltages according to the curve.

[0512] • Formula for calculating volume resistivity:

[0513]

[0514] ρ DC =Specific volume resistivity

[0515] U DC =DC voltage

[0516] A eff =Effective electrode surface considering the distance of the protective ring electrode.

[0517] d = see Figure 3

[0518] d1 = see Figure 3

[0519] g = see Figure 3

[0520] I stat = Steady-state current

[0521] The measurement duration is determined by plotting the current over time using a double logarithmic graph, mainly as follows: Figure 4 As shown. It reaches a steady state after 10 hours, so the measurement time is globally set to 20 hours.

[0522] Measurements were performed at room temperature unless otherwise specified. The electrodes were made of brass and polished before use. Conductive coatings (such as silver ink) were not used because the silicone provides good contact with the electrodes. For polarization, a PNChp-30000-2 DC power supply from Heinzinger was used, with a maximum voltage of 30 kV / mm and a maximum current of 2 mA. The minimum detectable current was 1 fA (nanoampere). The optimal resolution in the test setup was 10 fA.

[0523] Method conductivity: ISO 1853 ( (low volume resistivity)

[0524] Figure 5 The display shows the main setup for determining the volume resistivity of weakly conductive elastomers, with the corresponding dimensions according to [ISO 1853].

[0525] Further parameters:

[0526] Electrode material: Brass

[0527] • Do not use silver paste as contact support

[0528] ·U DC =60V

[0529] The test sample was a strip 2 cm wide and 2 mm thick, and the distance between the electrodes was 2 cm according to the aforementioned ISO standard. Measurements were performed at room temperature.

[0530] Figure 1 The volume resistivity of the cured composition varies with its carbon black content.

[0531] like Figure 1 As shown, the cured compositions of the present invention prepared using the carbon black masterbatch of the present invention surprisingly exhibit a much higher loading potential than conventional carbon black masterbatches (comparative example) before reaching the percolation point and becoming conductive. This allows for the addition of more CB while maintaining electrical strength and insulating properties.

[0532] Breakdown voltage:

[0533] The breakdown voltages of the compositions of the present invention and the comparative compositions with different amounts of carbon black were measured according to IEC 60243-2.

[0534] Figure 6 This shows the measurement setup according to IEC 60243-2.

[0535] The specific parameters are as follows:

[0536] - Maximum voltage is 100kV DC

[0537] - Sample thickness is 1mm, diameter is 45mm

[0538] -Asymmetric ball plate electrode design

[0539] -room temperature

[0540] -Measured in dried insulating oil Shell Diala S3 ZX-I according to IEC 60243-2.

[0541] - Voltage increase: 4kV / s

[0542] To avoid oil absorption, a so-called short-time (rapid rise) test is applied according to IEC 60243-2.

[0543] The generator allows a maximum output voltage of 100kV, which, when combined with a smoothing capacitor of Cg = 10nF, can achieve a maximum output of 140kV. The so-called ripple factor of DC is kept below 1%. The stress voltage is applied by a North Star VD 150 ohmic capacitor divider with a standard voltage division ratio of 10000:1 (DC error <0.1%).

[0544] The results show Figure 2 middle.

[0545] like Figure 2 As shown, the breakdown voltage in the cured silicone composition of the present invention can remain above 50 kV / mm even up to 2 wt% CB load. This determines the resistance to electrical stress under standard conditions. This parameter is a key factor in the functionality of cable joint insulation materials. Because breakdown leakage occurs earlier than volume resistivity leakage, it is more critical in the fine-tuning of the material. Electrical breakdown of the material leads to failure of the entire cable joint and renders the material unsuitable. A minimum value of 40-50 kV / mm should be achieved in measurements on 1 mm samples.

[0546] PEA measurement

[0547] PEA (Pulse Electroacoustic) measurements are used to locate the internal charge in materials such as silicone sheets. This allows for the measurement of the movement of internal charge over time caused by polarization current at a specific temperature. This method is crucial for the development and validation of insulation materials (cable accessories) for HVDC applications. It should be noted that all samples were 1 mm thick, and no silicone oil or grease was used at the sample interfaces, as silicone oil / grease was observed to migrate into the LSR. Fresh and depolarized LSR samples were used for each parameter combination. In the case of PEA, acoustic pulses are generated directly at the location of space charge, allowing their location to be determined via the velocity of the sound waves. Electrical pulses are generated within the sample by producing a short-term electric field E. p A voltage pulse. Due to its very short duration, it does not cause any further polarization, but it applies a Coulomb force and a subsequent pressure pulse to the space charge. This pulse propagates through the sample as an acoustic wave until it reaches the piezoelectric film, which converts the acoustic signal back into an electrical signal (electric signature).

[0548] Figure 7 This illustrates a schematic PEA test configuration. Here, e(t) represents the time-varying electrical pulse generated to activate the acoustic wave within the sample. The piezoelectric device, serving as the detector in this system, is backfilled with absorbing material to delay potential reflections without interfering with the initial wave signal. The initial wave is generated at t0 (see...). Figure 8 The sample then moves through the sample and reaches an Al electrode with a known thickness and impedance. The front end of the sample reaches the piezoelectric foil at t1, while the rear end reaches it at t2. The subsequent signal is a deliberately delayed reflection from inside the measuring device (t3, t4).

[0549] After correcting for the system response and other factors including calibration, the transformation to spatial coordinates (1D) essentially yields the following pattern, where charge density is a function of position (x). The total charge density (Q) can be calculated as follows:

[0550]

[0551] d = sample thickness

[0552] ρ = charge density

[0553] Figure 9 Display the conversion from voltage waveform to charge density graph.

[0554] (Sample thickness: 1mm);

[0555] Temperature according to separately mentioned polarization current (as mentioned separately).

[0556] A detailed description of the entire setup and signal processing for PEA (Pulse Electroacoustic) measurements is given below:

[0557] 1) R. Hussain, J. Moxter and V. Hinrichsen, “Development and optimization of a Pulsed Electroacoustic system suitable for silicone rubbers with carbon black nanofillers”, 10th International Conference on Insulated Power Cables, C4-1, Paris, 2019;

[0558] 2) R.Hussain and V.Hinrichsen, "Development and Optimization of a PulsedElectroacoustic System with Temperature Controlled Electrodes", 26th NordicInsulation Symposium on Materials, Components and Diagnostics, Tampere, Finland, 2019;

[0559] 3) G.C. Montanari and D. Fabiani, “Evaluation of DC insulation performance based on space-charge measurements and accelerated life tests”, IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 7, No. 3, June 2000, pp. 322-328;

[0560] 4) Antti Penttinen, Design of Pulled Electroacoustic Measurement System for Space Charge Characterization, Master's Thesis, Lappeenranta University of Technology, 2012, and further

[0561] 5) R. Hussain, PhD thesis “Electrical Characterization of Liquid Silicone Rubber with Carbon Black Nanofiller for HVDC Cable Accessories” TU Darmstadt (to be published in 2020).

[0562] PEA measurements are a method for demonstrating the concept of charge trapping, which creates a charge barrier that prevents further charge injection into the material and thus also prevents cable joint breakdown. The greater the amount of charge trapping, the stronger this charge barrier (i.e., so-called homogeneous charge) is established. According to the invention, CB is specifically used as a charge trapping material because the potential well for the charge is relatively deep and requires high energy to remove the charge from the potential well. This allows the charge to be held at the injection site, which in itself prevents further migration into the material and establishes the aforementioned charge barrier.

[0563] Figure 10 Showing the cured comparative sample SR 1 (0.47% CB) PEA charge shift plots at 60 °C and polarization times t = 10 s and t = 20 h.

[0564] Figure 11 Showing the cured comparative sample SR 1 (0.47% CB) PEA charge shift plots at 20 °C and polarization times t = 10 s and t = 20 h.

[0565] Figure 10 and Figure 11 The display shows that, considering the comparative SR 1 The acceptable breakdown voltage and volume resistivity allow only about 0.5 wt% CB load, an amount comparable to that of non-CB filled LSRs (see...). Figure 12 This provides a reduction in charge movement into the bulk material. However, the charge barrier properties of this filler level are insufficient for 525kV cable joints used in DC applications.

[0566] Figure 12 The cured embodiment of the present invention SR is shown. 1 PEA charge shift plots of the present invention's Example SR (1.52% CB) and CB content of 0.75 wt%, and a non-CB-filled cured composition (0 wt% CB) at 20°C and 60°C with a polarization time of t = 20 h.

[0567] Figure 12 This is based on the mathematical correlation given by Dr. R. Hussain (see the above references).

[0568] The cured organosilicon composition SR of the present invention 1 ( Figure 12 ) shows a comparison of SR with curing 1 ( Figure 10 and 11 Significantly different behavior. Non-CB-filled LSRs allow for the deepest penetration into the bulk material, which would lead to breakdown over time under DC conditions. The embodiments described show almost no migration over time even at elevated temperatures, allowing for use as insulation in DC applications.

[0569] Preferably, in the PEA charge transfer diagram determined according to the above method, the cured silicone composition SR according to the invention has a movement of any charge from one or each electrode of <0.2 mm, preferably <0.3 mm.

[0570] Preferably, the cured silicone composition SR according to the present invention moves less than 0.05 mm, preferably less than 0.1 mm, from one or each electrode in the PEA charge shift plot determined according to the above method.

Claims

1. A method for manufacturing an insulator or field equalization assembly for use in high-voltage applications, wherein a curable silicone composition is shaped by extrusion via a nozzle or by a die, and the shaped composition is cured by heat or light to form a shaped insulator or field equalization assembly, wherein a non-curable silicone composition is used as a masterbatch for incorporation into a curable silicone composition to manufacture the curable silicone composition, and the method for manufacturing the masterbatch includes extruding one or more polyorganosiloxanes (a1) together with one or more carbon blacks (d).

2. The method according to claim 1, wherein the weight ratio of the one or more polyorganosiloxanes (a1) to the weight of the one or more carbon blacks (d) is 90:10 to 75:

25.

3. The method according to claim 1 or 2, wherein the polyorganosiloxane (a1) is selected from polyorganosiloxanes having one or more unsaturated groups.

4. The method according to claim 3, wherein the polyorganosiloxane (a1) is selected from polyorganosiloxanes having one or more alkenyl groups.

5. The method according to claim 1 or 2, wherein in the method for manufacturing the masterbatch, the extrusion is carried out using an extruder.

6. The method according to claim 5, wherein the extruder is a multi-screw extruder.

7. The method according to claim 5, wherein the extruder is a twin-screw extruder.

8. The method according to claim 5, wherein the extruder is a co-rotating twin-screw extruder.

9. The method according to claim 1 or 2, wherein the weight ratio of the one or more polyorganosiloxanes (a1) to the weight of the one or more carbon blacks (d) is 89:11 to 80:

20.

10. The method according to claim 1 or 2, wherein the non-curing silicone composition comprises at least 10% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

11. The method of claim 10, wherein the non-curing silicone composition comprises at least 11% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

12. The method of claim 10, wherein the non-curing silicone composition comprises at least 12% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

13. The method of claim 10, wherein the non-curing silicone composition comprises 10-25% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

14. The method of claim 10, wherein the non-curing silicone composition comprises 11-24% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

15. The method of claim 10, wherein the non-curing silicone composition comprises 12-23% by weight of one or more carbon blacks based on the total weight of the entire silicone composition.

16. The method according to claim 1 or 2, wherein the percentage of particles smaller than 10 µm in the non-curing silicone composition is greater than 70%, and / or the percentage of particles larger than 10 µm is less than 30%, each determined by dynamic light scattering. And / or the particle size distribution Dn based on the number of particles in the non-curing silicone composition. 50 Less than 7 µm, measured by dynamic light scattering. And / or the particle size distribution Dn based on the number of particles in the non-curing silicone composition. 90 Less than 15 µm, measured by dynamic light scattering.

17. The method of claim 16, wherein the percentage of particles smaller than 10 µm in the non-curing silicone composition is greater than 80%, as determined by dynamic light scattering.

18. The method of claim 16, wherein the percentage of particles smaller than 10 µm in the non-curing silicone composition is greater than 90%, as determined by dynamic light scattering.

19. The method of claim 16, wherein the percentage of particles larger than 10 µm in the non-curing silicone composition is less than 20%, as determined by dynamic light scattering.

20. The method of claim 16, wherein the percentage of particles larger than 10 µm in the non-curing silicone composition is less than 10%, as determined by dynamic light scattering.

21. The method of claim 16, wherein the percentage of particles larger than 10 µm in the non-curing silicone composition is less than 5%, as determined by dynamic light scattering.

22. The method of claim 16, wherein Dn is based on the particle size distribution of the number of particles in the non-curing silicone composition. 50 Less than 5 µm, measured by dynamic light scattering.

23. The method of claim 16, wherein Dn is based on the particle size distribution of the number of particles in the non-curing silicone composition. 50 Less than 3 µm, measured by dynamic light scattering.

24. The method of claim 16, wherein Dn is based on the particle size distribution of the number of particles in the non-curing silicone composition. 90 Less than 10 µm, measured by dynamic light scattering.

25. The method of claim 16, wherein Dn is based on the particle size distribution of the number of particles in the non-curing silicone composition. 90 Less than 8 µm, measured by dynamic light scattering.

26. The method of claim 16, wherein Dn is based on the particle size distribution of the number of particles in the non-curing silicone composition. 90 Less than 5 µm, measured by dynamic light scattering.

27. The method according to claim 1 or 2, wherein the curable silicone composition comprises: a) 100 pt.wt. of one or more polyorganosiloxanes having one or more unsaturated groups a2), b) 0 – 100 pt.wt. of a crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes. c) One or more filler components of 0 – 100 pt.wt., comprising one or more reinforcing silica or resins. d) One or more types of carbon black, 0.1 – 3 pt.wt. e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and f) One or more auxiliary additives of 0 – 50 pt.wt.

28. The method of claim 27, wherein the polyorganosiloxane (a2) has one or more alkenyl groups.

29. The method of claim 27, wherein the curable silicone composition comprises 0.1-2.4 wt% of one or more carbon blacks based on the total weight of the curable silicone composition.

30. The method of claim 27, wherein the curable silicone composition comprises 0.2-2.4 wt% of one or more carbon blacks based on the total weight of the curable silicone composition.

31. The method of claim 27, wherein the curable silicone composition comprises 0.5-2.2 wt% of one or more carbon blacks based on the total weight of the curable silicone composition.

32. The method of claim 27, wherein the curable silicone composition comprises 1.0-2.0 wt% of one or more carbon blacks based on the total weight of the curable silicone composition.

33. The method of claim 27, wherein the curable silicone composition comprises 1.3-1.8 wt% of one or more carbon blacks based on the total weight of the curable silicone composition.

34. The method according to claim 1 or 2, wherein the curable silicone composition comprises: a) 100 pt.wt. of one or more polyorganosiloxanes having one or more unsaturated groups a2), b) 0 – 100 pt.wt. of a crosslinking agent component comprising one or more polyorgano-based hydrosiloxanes. c) One or more filler components of 0 – 100 pt.wt., comprising one or more reinforcing silica or resins. d) One or more types of carbon black with a content greater than 2 pt.wt. e) A curing catalyst selected from compounds and organic peroxides capable of achieving hydrosilylation, and f) One or more auxiliary additives, 0 – 50 pt.wt. And a cured silicone composition obtained by curing the cured silicone composition.

35. The method of claim 34, wherein the polyorganosiloxane (a2) has one or more alkenyl groups.

36. The method of claim 34, wherein the curable silicone composition comprises 4 pt.wt. – 12 pt.wt. of one or more carbon blacks.

37. An insulator or field equalization assembly for high voltage direct current applications, obtained by means of the method according to any one of claims 1-36.

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