SILICONS AND SILICONE LABELS FOR THE SURFACE TREATMENT OF POLYMERIZABLE MATERIALS IN MEDICAL TECHNOLOGY, ESPECIALLY IN THE HEARING AID ACOUSTICS SECTOR

Description

[0001] The invention relates to the production and use of a composition and a lacquer for the surface treatment of polymerizable materials, in particular based on polyorganosiloxanes. The invention relates to silicones and lacquers for the surface treatment of silicones used in medical technology. In particular, the invention relates to silicones and lacquers for the surface treatment of silicones used in the dental and hearing aid acoustics sectors, examples of which include silicones for noise protection and silicones for swimming protection.

[0002] This prior art is known from EP 1 777 264 A1. State of the art:

[0003] Both indirect and direct processes are currently used to manufacture silicone earmolds for noise and swimming. Because the demands on comfort are very high, the shape and fit of the silicone earmold are of utmost importance. Addition-curing silicones have proven particularly suitable, as they exhibit low shrinkage and are therefore particularly dimensionally stable.

[0004] According to the state of the art, addition-curing silicones consist of the following components (all or a combination of these components): (1) Polyorganosiloxanes with at least two unsaturated groups in the molecule (meaning vinyl groups) (2) Polyorganohydrogensiloxanes with at least two SiH groups in the molecule (without vinyl groups) (3) Polyorganosiloxanes without reactive groups (i.e. neither vinyl groups nor SIH groups) (4) Precious metal catalyst(s) (5) Reinforcing fillers, with loaded or unloaded surface (6) Non-reinforcing fillers (7) Oils or other plasticizers (8) Other additives and usual additives, auxiliaries and dyes (9) Inhibitors

[0005] The compounds according to (1) are polyorganosiloxanes with terminal and / or pendant reactive groups having a viscosity at 23 °C of about 50 mPa s to 165,000 mPa s, preferably 200 mPa s to 65,000 mPa s.

[0006] The compounds according to (2) contain reactive SiH groups, which build up the polymer in an addition reaction under noble metal catalysis with the compounds (1).

[0007] The compounds according to (3) include silicone oils, which, like the compounds according to (1), are polyorganosiloxanes, but do not contain reactive groups and thus do not participate in the noble metal-catalyzed addition crosslinking reaction. Such compounds are described, for example, in W. Noll's "Chemistry and Technology of Silicones," Verlag Chemie Weinheim, 1968.

[0008] The noble metal catalyst (4) is preferably a platinum complex; platinum-siloxane complexes, as already described in US-A-3,715,334, US-A-3,775,352, and US-A-3,814,730, are particularly suitable. UV-active platinum complexes, as already described in EP 0 122 008 A1 and DE 10 2008 000 156 A1, are particularly suitable for radiation-curing silicone compositions.

[0009] Reinforcing fillers according to (5) generally have a BET surface area greater than 50 m 2 / g. These include, for example, pyrogenic or precipitated silicas and silicon-aluminum mixed oxides. These fillers can be hydrophobized by surface treatment with, for example, hexamethyldisilazane or organosiloxanes or organosilanes.

[0010] The non-reinforcing fillers according to (6) have a BET surface area of ​​up to 50 m 2 / g. These include quartz, cristobalite, diatomaceous earth, kieselguhr, calcium carbonates, talc, zeolites, sodium aluminum silicates, metal oxide, and glass powders. These fillers, like the reinforcing fillers, can also be hydrophobized by surface treatment.

[0011] As a compound according to (7), for example, hydrocarbons can be considered, particularly preferred are paraffin oils and isoeicosans.

[0012] Furthermore, color pigments and other auxiliaries such as finely divided platinum or palladium as hydrogen absorbers may be included as additives. To control reactivity, it may be necessary to use inhibitors (9). Such inhibitors are known and described, for example, in US Pat. No. 3,933,880. These are generally acetylenically unsaturated alcohols or vinyl-containing polysiloxanes, oligosiloxanes, and disiloxanes.

[0013] The compositions are preferably formulated in two components to ensure storage stability. The entire content of precious metal catalysts (4) is contained in the first catalyst component, while the entire content of SiH compounds (2) is contained in the second component, which is spatially separated from the first component. By mixing the two components, the compositions cure in an addition reaction known as hydrosilylation. Depending on the selection of the precious metal catalysts (4) (UV-active or UV-inactive) and the addition of the inhibitors (9), the reaction can be accelerated (with or without UV radiation) or slowed down.

[0014] The volume ratios of the two components can be 10:1 to 1:10. Volume mixing ratios of 1:1, 4:1, 5:1, and 10:1 (base to catalyst component) are particularly preferred.

[0015] Some silicone earmolds are coated with a state-of-the-art lacquer as a surface finish. This lacquer has the following composition: (1) Polyorganosiloxanes with at least two unsaturated groups in the molecule (2) Polyorganohydrogensiloxanes with at least two SiH groups in the molecule (3) Polyorganosiloxanes without reactive groups (4) Noble metal catalyst(s) (5) Reinforcing fillers, with loaded or unloaded surface (6) Inhibitors (7) Organic solvents

[0016] The points listed above apply to compounds (1) to (6). This varnish is also a two-component material, and the comments made apply here as well. The organic solvents used according to the invention have a boiling point at 1013 hPa in the range of 40-200 °C, preferably in the range of 70-170 °C, particularly preferably in the range of 100-165 °C. Cyclic and aliphatic hydrocarbons as well as molecules from the siloxane range are suitable. Examples include cyclohexane, n-hexane, n-heptane, toluene, benzine, hexamethyldisiloxane, or octamethyltrisiloxane.

[0017] Silicone earmolds in the form of noise protection or swimming protection are usually worn in the ear for extended periods of time. Therefore, special attention must be paid to hygiene. The use of silicones in the field of noise protection and swimming protection is well known because they offer a broad spectrum of mechanical and physical properties and have the additional advantage of having little or no toxic, sensitizing, or allergenic potential. This makes them ideal for medical applications. The precise fit of earmolds plays a particularly important role. The earmold is in direct contact with the skin of the ear. The moist and warm environment in the ear canal provides ideal conditions for the growth of microorganisms (bacteria, viruses, fungi, algae), which are known to colonize silicone.This not only compromises hygiene but also the aesthetics of earmolds worn in the ear for extended periods of time for noise protection, for example, while working or as a swimmer's ear protector. In particular, inflammation can occur if the skin of the ear canal is irritated by pressure points (due to a poor fit of the earmold) or friction from chewing. Another important hygiene issue is the dust attraction of common silicones, which poses a problem in daily use.

[0018] Due to the above-mentioned points, the preparation of an antistatic, biocompatible and mechanically resilient silicone coating in the form of a polymerization reaction (room temperature curing or UV radiation curing) is desirable.

[0019] Antistatic silicones have been known for many years. They are used as release films on semiconductor, electronic, and display devices where static electricity problems can arise. Examples have been described by Toray Saehan Inc. in WO2008114916A1. , which obtain the antistatic properties by polymerizing polythiophenes or derivatives and by Shin-Etsu Polymer Co. Ltd. in EP2894207A1 , which contains at least one amine-like compound selected from the group consisting of a secondary amine, a tertiary amine, or a quaternary ammonium salt with a counteranion. Further silicones with antistatic properties, which are produced by adding conductive additives, were developed by Shin-Etsu by adding molecules with epoxy and vinyl units in WO2016093124A1. ,through the use of various lithium salts in US20080260981A1 and through the use of secondary and tertiary amines or quaternary ammonium salts, which are positively charged and contain a counter anion (so-called ionic liquids) in US9624398B2. Antimicrobial antistatic products were also described over 20 years ago by Dow Corning Toray Co. Ltd. in EP0233954B1.

[0020] However, all mentioned and published additives with antistatic properties do not meet the high requirements that must be met by polymerizable materials that are worn in the ear for a longer period of time, such as noise and swimming protection earmolds: The antistatic additive must be non-toxic and have no sensitizing or allergenic potential, or it must be non-toxic and have no sensitizing or allergenic potential within the entire composition. The antistatic additive should be present in the polymerizable mass in sufficient quantity to exert its effect on the material surface. The antistatic additive must not inhibit the polymerization reaction and must not alter the typical properties of the polymer.

[0021] The aim of the invention is therefore to provide a material for earmolds, especially for noise and swimming protection, that possesses biocompatible and antistatic properties, is highly resilient, and lacks the aforementioned negative properties. This goal is achieved by using the correct concentration of one or more antistatic additives and the corresponding silicone composition. While the antistatic additive is responsible for the antistatic properties, the correct silicone composition provides the mechanically resilient properties. The correct concentration of the antistatic additive contributes to ensuring, on the one hand, the biocompatibility of the silicone and, on the other hand, that the antistatic properties are sufficiently good for use.

[0022] The aim of this invention is also to provide a corresponding silicone-based varnish. This aim is achieved in the same way by using one or more antistatic additives to the varnish. This antistatic varnish for the surface treatment of silicones should be applicable both by conventional brush and dipping methods and by spraying methods (manually using airbrush technology or mechanically using, for example, the DACS automatic varnishing system from Dreve Otoplastik GmbH). The invention achieves this objective by the composition and use specified in the patent claims.

[0023] In this context, it is important to have a reliable and reproducible method for measuring the antistatic properties of plastic surfaces in general, but especially of silicone surfaces.

[0024] The most reliable indicator of the antistatic properties of plastic surfaces in general, but especially of silicone surfaces, is the surface resistance, which is directly related to the conductivity, since the current charge of the plastic / silicone does not distort the measurement result. From the surface resistance, conclusions can be drawn directly about the chargeability and thus also about the tendency of the plastic / silicone to attract dust particles (from the operating instructions of the MECO Antistatic Tester MGT-4).

[0025] Surprisingly, it has been found that polymerizable materials, particularly those based on polyorganosiloxanes, can be made antistatic by adding one or more antistatic additives, while the essential properties of the materials remain unaffected by the addition: unchanged storage stability unchanged processing and curing times unchanged hardness unchanged viscosities unchanged workability

[0026] The surface texture remains unchanged. However, the surface has antistatic properties, which prevent dust and dirt particles from being attracted and significantly reduce their accumulation on the surface. Dust particles deposited on the surface can be easily removed by blowing or wiping. Silicone compounds without antistatic properties, as is known for silicone, attract significantly more dust. This dust cannot be easily removed by blowing or wiping.

[0027] The antistatic additives are polyether-modified siloxanes, which are surface-active trisiloxanes, such as those available from Gelest, Evonik Industries AG, and Momentive. Examples include the products MCS-E15, MCR-E21, and MCR-E11 (propyl ether-modified siloxanes) from Gelest and the TEGOPREN products TEGOPREN 5803, TEGOPREN 5840, TEGOPREN 5852, TEGOPREN 5857, TEGOPREN 5863, TEGOPREN 5864, TEGOPREN 5884, and TEGOPREN 5884-35 from Evonik Industries AG. Also worth mentioning are the Silwet products L-77 and L-7280 from Momentive. The antistatic effects of these additives are known to those skilled in the art and can be traced in the relevant literature. The concentration of these additives is particularly important. The higher the trisiloxane concentration, the stronger the antistatic effect in the silicone composition.

[0028] The polyether-modified siloxanes are surface-active trisiloxanes with a hydrophobic siloxane portion (30-50 wt.%) and a hydrophilic portion of ethylene and / or propylene oxide (50-70 wt.%).

[0029] The polyether siloxanes mentioned are surface-active trisiloxanes. These are small, therefore highly mobile molecules. They interact in two ways and are necessary for the antistatic effect: the interaction of the hydrophobic siloxane component with the base mixture used, which is composed of vinyl-functional polydimethylsiloxanes and special fillers. This allows the polyether siloxane to be incorporated into the silicone matrix of the silicone coating without thickening (increasing viscosity) at the selected concentration. This would be unfavorable for application as a coating. The hydrophilic component (ethylene and / or propylene oxide components) interacts with atmospheric moisture, moistening the silicone surface and thus making it conductive. Charges can flow away more easily, making the surface antistatic. Surfaces coated in this way can neither build up nor retain electrical charge.

[0030] The following embodiments serve to describe the invention in more detail; they are very detailed and are not intended to limit the invention in any way. Example 1: transparent silicone material (comparison example) Catalyst component

[0031] 1.9 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 200 mPa s 1.9 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 1,000 mPa s 2.8 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 10,000 mPa s 50.4 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 65,000 mPa s 8.9 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 12.0 wt.% of a paraffin oil 21.7 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 0.4 wt.% of a platinum catalyst are initially charged and mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Basic component

[0032] 1.9 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 1.9 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 2.9 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 49.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 3.1 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 7.6 wt.% of a paraffin oil 21.2 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 11.8 wt.% of a polymethylhydrogensiloxane with an SiH content of 2.3 mmol / g are initially introduced and The mixture is mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Mixture of catalyst and base component

[0033] Fifty parts of the catalyst component and 50 parts of the base component are dispensed from a double cartridge and mixed homogeneously using a static mixer. This results in a cured specimen with a final hardness of 40 Shore A and excellent mechanical properties (tensile strength, elongation at break). Surface resistance: >1*10 12< Ω (not antistatic). Example 2: transparent silicone varnish (comparison example) Catalyst component

[0034] 67.6 wt% of hexamethyldisiloxane with a viscosity of 0.5 mPa s 13.5 wt% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 18.9 wt% of a platinum catalyst are initially introduced and mixed homogeneously for 30 minutes. Basic component

[0035] 9.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 3.4 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 4.9 wt.% vinyl-terminated polydimethylsiloxane resin with a viscosity of 1,000 mPa s 15.5 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 40.8 wt.% hexamethyldisiloxane with a viscosity of 0.5 mPa s 15.9 wt.% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 6.6 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 3.9 wt.% of a polymethylhydrogensiloxane with a SiH content of 7.3 mmol / g is added and mixed homogeneously for 30 minutes. Mixture of catalyst and base component

[0036] One part of the catalyst component and 10 parts of the base component are mixed homogeneously using a static mixer. A cured test specimen with a final hardness of 25 Shore A is obtained. The mechanical properties are inadequate and cannot be clearly determined. Surface resistance: >1*10 12< Ω (not antistatic). Example 3: transparent silicone material (according to the invention) Catalyst component

[0037] 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 2.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 50.4 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 8.9 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 11.9 wt.% of a paraffin oil 21.7 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 0.4 wt.% of a platinum catalyst 0.1 wt.% polyethersiloxane, namely trisiloxane are initially introduced and The mixture is mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Basic component

[0038] 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 2.7 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 49.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 3.1 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 7.5 wt.% of a paraffin oil 21.2 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 11.8 wt.% of a polymethylhydrogensiloxane with an SiH content of 2.3 mmol / g 0.1 100% by weight of polyethersiloxane, namely trisiloxane, is added and mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Mixture of catalyst and base component

[0039] Fifty parts of the catalyst component and 50 parts of the base component are dispensed from a double cartridge and mixed homogeneously using a static mixer. A cured test specimen is obtained with a final hardness of 40 Shore A and excellent mechanical properties (tensile strength, elongation at break). Surface tension: 5*10 9 < Ω (antistatic). Example 4: transparent silicone material (according to the invention) Catalyst component

[0040] 3.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 1.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 50.4 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 8.9 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 11.8 wt.% of a paraffin oil 21.7 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 0.4 wt.% of a platinum catalyst 0.2 wt.% polyethersiloxane, namely trisiloxane are initially introduced and The mixture is mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Basic component

[0041] 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 2.7 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 49.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 3.1 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 7.4 wt.% of a paraffin oil 21.2 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 11.8 wt.% of a polymethylhydrogensiloxane with an SiH content of 2.3 mmol / g 0.2 100% by weight of polyethersiloxane, namely trisiloxane, is added and mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Mixture of catalyst and base component

[0042] Fifty parts of the catalyst component and 50 parts of the base component are dispensed from a double cartridge and mixed homogeneously using a static mixer. A cured test specimen is obtained with a final hardness of 40 Shore A and excellent mechanical properties (tensile strength, elongation at break). Surface tension: 2*10 9 < Ω (antistatic). Example 5: transparent silicone material (according to the invention) Catalyst component

[0043] 3.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 200 mPa s 2.0 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 1,000 mPa s 1.6 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 50.4 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 65,000 mPa s 9.0 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 11.6 wt.% of a paraffin oil 21.7 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 0.4 wt.% of a platinum catalyst 0.3 wt.% polyethersiloxane, namely trisiloxane are initially introduced and The mixture is mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Basic component

[0044] 4.0 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 200 mPa s 2.7 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 10,000 mPa s 49.6 wt.% vinyl-end-stopped polydimethylsiloxane with a viscosity of 65,000 mPa s 3.1 wt.% of a polydimethylsiloxane oil with a viscosity of 50 mPa s 7.3 wt.% of a paraffin oil 21.2 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 < / g 11.8 wt.% of a polymethylhydrogensiloxane with an SiH content of 2.3 mmol / g 0.3 wt.% polyethersiloxane, namely trisiloxane are initially charged and mixed homogeneously for 30 minutes. The mixture is then degassed under vacuum for 15 minutes. Mixture of catalyst and base component

[0045] Fifty parts of the catalyst component and 50 parts of the base component are dispensed from a double cartridge and mixed homogeneously using a static mixer. A cured test specimen is obtained with a final hardness of 40 Shore A and excellent mechanical properties (tensile strength, elongation at break). Surface tension: 2*10 9 < Ω (antistatic). Example 6: transparent silicone varnish (according to the invention) Catalyst component

[0046] 67.6 wt% of hexamethyldisiloxane with a viscosity of 0.5 mPa s 13.5 wt% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 18.9 wt% of a platinum catalyst are initially introduced and mixed homogeneously for 30 minutes. Basic component

[0047] 30.1 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 43.2 wt.% hexamethyldisiloxane with a viscosity of 0.5 mPa s 11.4 wt.% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 13.0 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 2.2 wt.% of a polymethylhydrogensiloxane with an SiH content of 7.3 mmol / g 0.1 wt.% polyethersiloxane, namely trisiloxane are initially charged and mixed homogeneously for 30 minutes. Mixture of catalyst and base component

[0048] One part of the catalyst component and 10 parts of the base component are homogeneously mixed using a static mixer. A cured specimen with a final hardness of 25 Shore A is obtained. The mechanical properties are shown below: Elongation at break: 342%, tensile strength: 2.8 MPa, force at break: 18.4 N, tear strength: 9.0 kN / m at a thickness of 2.9 mm. Surface tension: 5*10 9 < Ω (antistatic). Example 7: transparent silicone varnish (according to the invention) Catalyst component

[0049] 67.6 wt% of hexamethyldisiloxane with a viscosity of 0.5 mPa s 13.5 wt% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 18.9 wt% of a platinum catalyst are initially introduced and mixed homogeneously for 30 minutes. Basic component

[0050] 30.1 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 43.2 wt.% hexamethyldisiloxane with a viscosity of 0.5 mPa s 11.3 wt.% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 13.0 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 2.2 wt.% of a polymethylhydrogensiloxane with an SiH content of 7.3 mmol / g 0.2 wt.% polyethersiloxane, namely trisiloxane are initially charged and mixed homogeneously for 30 minutes. Mixture of catalyst and base component

[0051] One part of the catalyst component and 10 parts of the base component are homogeneously mixed using a static mixer. A cured specimen with a final hardness of 25 Shore A is obtained. The mechanical properties are shown below: Elongation at break: 340%, tensile strength: 2.7 MPa, force at break: 18.3 N, tear strength: 9.0 kN / m at a thickness of 2.9 mm. Surface tension: 2*10 9 < Ω (antistatic). Example 8: transparent silicone varnish (according to the invention) Catalyst component

[0052] 67.6 wt% of hexamethyldisiloxane with a viscosity of 0.5 mPa s 13.5 wt% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 18.9 wt% of a platinum catalyst are initially introduced and mixed homogeneously for 30 minutes. Basic component

[0053] 30.1 wt.% vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa s 43.2 wt.% hexamethyldisiloxane with a viscosity of 0.5 mPa s 11.2 wt.% of a polydimethylsiloxane oil with a viscosity of 10 mPa s 13.0 wt.% of a pyrogenic silica (surface-treated) with a BET surface area between 150 and 200 m 2 / g 2.2 wt.% of a polymethylhydrogensiloxane with an SiH content of 7.3 mmol / g 0.3 wt.% polyethersiloxane, namely trisiloxane are initially charged and mixed homogeneously for 30 minutes. Mixture of catalyst and base component

[0054] One part of the catalyst component and 10 parts of the base component are homogeneously mixed using a static mixer. A cured specimen with a final hardness of 25 Shore A is obtained. The mechanical properties are shown below: Elongation at break: 341%, tensile strength: 2.7 MPa, force at break: 18.4 N, tear strength: 9.0 kN / m at a thickness of 2.9 mm. Surface tension: 2*10 9 < Ω (antistatic).

Claims

1. A two-component, addition-crosslinking silicone, crosslinking at room temperature or with UV radiation, consisting of at least (1) 0.1 - 70% by weight of polyorganosiloxanes with at least two unsaturated groups in the molecule, (2) 0.1 - 15% by weight of polyorganosiloxanes with at least two SiH groups in the molecule, (3) 0.1 - 10 % by weight polyorganosiloxanes without reactive groups, (4) 0.01 - 2.0 % by weight precious metal catalyst (UV-active / inactive, depending on application), (5) 0.1 - 30% by weight of reinforcing fillers, with a loaded or unloaded surface, and (6) 0.01 - 0.5% by weight of at least one antistatic additive, namely polyether-modified siloxanes which are surface-active trisiloxanes.

2. The silicone according to claim 1 with additionally, individually, or together, (1) up to 30% by weight of oils or other plasticizers, and / or (2) up to 20% by weight of non-reinforcing fillers, and / or (3) up to 1% by weight of inhibitors.

3. The silicone according to claim 1 or 2, characterized in that the antistatic additive is a surface-active trisiloxane.

4. A silicone varnish, which is both room-temperature-curing and UV-curing and is intended for the surface coating of earmolds without inherent antistatic properties, consisting of: (1) 0.1 - 50% by weight of polyorganosiloxanes with at least two unsaturated groups in the molecule, (2) 0.1 - 15% by weight of polyorganosiloxanes with at least two SiH groups in the molecule, (3) 0.1 - 10 % by weight polyorganosiloxanes without reactive groups, (4) 0.01 - 2.0 % by weight precious metal catalyst (UV-active / inactive, depending on application), (5) 0.1 - 30 % by weight reinforcing fillers, with loaded or unloaded surface, (6) 0.1 - 50% by weight of organic solvents, and (7) at least 0.01 - 0.5% by weight of an antistatic additive, namely polyether-modified siloxanes which are surface-active trisiloxanes.

5. The silicone varnish according to claim 4, which additionally contains up to 30% by weight of oils or other plasticizers, and / or up to 20% by weight of non-reinforcing fillers, and / or up to 1% by weight of inhibitors.

6. The silicone varnish according to claim 4 or 5, characterized in that the antistatic additive is a surface-active trisiloxane or a combination of surface-active trisiloxanes.

7. The silicone varnish according to one of claims 4 to 6, characterized in that the antistatic silicone varnish can be used for the surface treatment of silicones both by brushing and dipping methods and by spraying methods (manually by airbrush technique or mechanically with an automatic painting system).