Method for the manufacture of electrically insulating protective gloves with arc protection and such protective gloves

Description

TECHNICAL FIELD

[0001] The invention relates to a method for manufacturing electrically insulating protective gloves with arc flash protection based on thermoplastic elastomers in combination with a pigment. The method is carried out, in particular, without vulcanization. The invention further relates to such protective gloves. TECHNICAL BACKGROUND

[0002] Currently, protective gloves against electrical discharge are generally made of natural rubber or synthetic polyisoprene. For practical use, electrically insulating protective gloves must meet requirements regulated in relevant standards, such as the European standard IEC 60903:2014 and the US standard ASTM D120-21. According to these standards, electrically insulating protective gloves are classified into classes and sizes. The lengths are also specified by the aforementioned standards. Table 1 below details the respective classes and their corresponding values ​​for the maximum operating voltage in volts and the test voltage in volts according to IEC and ASTM. Table 1: Protection class classification and corresponding requirements for electrically insulating protective gloves according to IEC and ASTM. Class Length in [mm] Maximum operating voltage in volts Test voltage in volts 00 280 / 360 mm 500 V 2500 V 0 280 / 360 / 410 / 460 mm 1000 V 5000 V 1 360 / 410 / 460 mm 7500 V 10 000 V 2 360 / 410 / 460 mm 17 000 V 20 000 V 3 360 / 410 / 460 mm 26 500 V 30 000 V 4 410 / 460 mm 36 000 V 40 000 V

[0003] In addition to preventing electrical discharges, electrically insulating protective gloves must also meet certain mechanical requirements, such as tensile strength (e.g., > 16 N / mm² < MPa); elongation at break (e.g., > 600%); permanent elongation (deformation resistance, e.g., < 15%); puncture resistance (e.g., > 18 N); and resistance to fire spread (e.g., no flame spread after 55 seconds of exposure to fire) and resistance to cold. Furthermore, electrically insulating protective gloves should generally also be resistant to heat, oil, ozone, acid, and extremely low temperatures.

[0004] The aforementioned standards also specify the thickness (material thickness, wall thickness) of electrically insulating protective gloves for practical use at certain discharge intensities; for example, a maximum wall thickness of 0.50 mm is permitted for class 00, a maximum wall thickness of 1.00 mm for class 0, a maximum wall thickness of 1.50 mm for class 1, a maximum wall thickness of 2.30 mm for class 2, a maximum wall thickness of 2.90 mm for class 3, and a maximum wall thickness of 3.60 mm for class 4.

[0005] Due to their material properties, natural rubber and synthetic polyisoprene are currently the only materials that meet the requirements of common standards for electrically insulating protective gloves.

[0006] In addition to the requirements already mentioned, arc resistance is increasingly required for electrically insulating protective gloves in practical applications, as arcs can occur during work with electricity and, triggered by short circuits, manifest as a continuous discharge of high voltage in the air between two electrodes. The consequences can be burns to the skin and body due to extreme heat. Arc faults can also ignite fires. Arc explosions with pressure waves of up to 1000 kg / m² can cause serious injuries. Sound waves up to 140 dB and ultraviolet light can lead to damage to hearing and eyes.

[0007] Common methods for manufacturing electrically insulating protective gloves from natural rubber and synthetic polyisoprene all involve the vulcanization process. However, vulcanization has significant drawbacks. It is energy-intensive. Protective gloves vulcanized with sulfur can contain allergens. Furthermore, allergens can also be present in natural rubber itself. Due to the chemical changes that occur during vulcanization, the glove material cannot be reused or recycled in the manufacturing process.

[0008] In view of the aforementioned disadvantages of conventional methods, it is an object of the present invention to provide a method for manufacturing electrically insulating protective gloves with arc flash protection that is energy-efficient, does not use or generate any allergenic components, and allows waste material generated during production or gloves produced by the method to be recycled back into the manufacturing process. Furthermore, the electrically insulating protective gloves with arc flash protection should meet the requirements of common standards.

[0009] JP5521003 B2 relates to an electrically insulating protective glove with arc flash protection and discloses the features of the preamble of claims 1 and 14. SOLUTION TO THE PROBLEM

[0010] The problem is solved by the features of independent claims 1 and 14. The dependent claims are directed to preferred embodiments of the invention. According to the invention, a method for manufacturing electrically insulating protective gloves with arc flash protection (hereinafter also referred to as protective glove or glove) initially comprises the step of providing a starting material. The starting material consists essentially of two thermoplastic elastomers. In other words, the starting material consists essentially of a mixture of two thermoplastic elastomers.

[0011] The phrase "essentially consisting of" is to be interpreted here as meaning almost complete, but does not preclude the possibility that a few additional components, as described herein, may be added to the starting material. Thermoplastic elastomers are polymers, usually copolymers, whose chains are structured such that they possess the following three properties: Thermoplastic elastomers can be stretched to moderate elongation and the structure practically returns to its original shape after the load is removed; thermoplastic elastomers can be processed easily at elevated temperatures; and thermoplastic elastomers are characterized by interactions of a physical nature.

[0012] Thermoplastic elastomers (TPEs) represent a distinct class of materials. In terms of their properties and processing capabilities, they lie between thermoplastics and elastomers. TPEs combine the processing properties of thermoplastics, such as heat deformation, with the softness and flexibility of elastomers. The properties of TPE materials can be specifically controlled by producing polymer mixtures or blends, for example, by having one polymer component primarily contribute elastic properties, while the other(s) contribute more thermoplastic properties to the resulting compound. This aspect is utilized in the present invention by using a starting material that essentially consists of a mixture of two thermoplastic elastomers.

[0013] The use of TPEs offers numerous advantages over conventional materials. For example, the use of TPEs eliminates the need for latex, polyvinyl chloride (PVC), phthalates, or heavy metals, thus avoiding the addition of allergenic components.

[0014] According to the invention, the thermoplastic elastomers used are not fundamentally restricted with regard to their structure. However, TPEs with styrene block copolymers (SBCs), which are generally referred to as TPE-S or TPS, are preferably used. The most common types of SBCs include: SBS: Styrene-butadiene-styrene block copolymer; SIS: Styrene-isoprene-styrene block copolymer; SEBS: Styrene-ethylene-butylene-styrene block copolymer and SEPS: Styrene-ethylene-propylene-styrene block copolymer.

[0015] The inventors have discovered that the properties of SEBS-based thermoplastic elastomers are particularly advantageous for the production of electrically insulating protective gloves with arc flash protection. SEBS-based thermoplastic elastomers exhibit very good elasticity and flexibility, as well as excellent mechanical properties such as tensile strength, elongation at break, permanent elongation, puncture resistance, and tear strength. SEBS-based thermoplastic elastomers can be formulated to be translucent or transparent, allowing for a wide range of coloring options. Furthermore, SEBS-based thermoplastic elastomers offer a broad spectrum of potential additive applications, especially for pigments and dyes.Furthermore, materials made from SEBS-based thermoplastic elastomers offer properties that are also very important for additional categories and requirements in the practical application of electrically insulating protective gloves. For example, SEBS-based thermoplastic elastomers offer higher temperature stability than thermoplastics, which is particularly important for arc flash protection with regard to heat generation. SEBS-based thermoplastic elastomers are elastic at low temperatures down to -40°C, thus enabling resistance to extreme cold. SEBS-based thermoplastic elastomers exhibit excellent resistance to UV radiation, ozone, and weathering, especially in oxidative environments.SEBS-based thermoplastic elastomers are resistant to oils and greases at high temperatures, as well as to high-temperature barrier fluids and water-based solutions, such as acids. According to a preferred embodiment, the two thermoplastic elastomers can therefore be, in particular, styrene-ethylene-butylene-styrene (SEBS)-based thermoplastic elastomers. This means that the starting material can preferably consist essentially of a mixture of two styrene-ethylene-butylene-styrene (SEBS)-based thermoplastic elastomers.

[0016] The mixture essentially consists of a first SEBS-based component and a second SEBS-based component. The first SEBS-based component preferably has a molecular structure of 50-200 units and a polystyrene content of approximately 12-15%. This first component therefore preferably exhibits high elasticity, reflected in high elongation. The second SEBS-based component preferably has a molecular structure of 50-200 units and a polystyrene content of 30-35%. This second component therefore preferably exhibits high mechanical resistance and thus high tensile strength. By combining the two components, the properties of the starting material can be specifically tailored through the individual properties of the two thermoplastic elastomers.

[0017] According to a further preferred embodiment, the starting material can additionally consist of a styrene-based polymeric auxiliary component. The styrene-based polymeric auxiliary component is preferably SBS, SIS, SEBS, SEPS, or a mixture of these components; SBS or SEBS, or a mixture of these two, is particularly preferred. The styrene-based polymeric auxiliary component preferably has a molecular structure of between 50 and 200 units and a polystyrene content of more than 50%. The auxiliary component may be present in the starting material in a smaller quantity. Its function is to improve the properties of the two preceding components, for example, by reinforcing the hard areas of the polymeric mixture, thereby increasing its structural stability.In this way, products with high values ​​in terms of standard requirements can be obtained without the need for a vulcanization process.

[0018] A three-component compound is particularly preferred as the starting material, wherein the compound consists of two SEBS-based thermoplastic elastomers and a styrene-based polymeric auxiliary component. The hardness of the compound is preferably in the range of 30 to 60 Shore A (DIN ISO 7619-1) or 47 Shore A (DIN ISO 48-4). The density of the compound is preferably 0.940 g / cm³ (DIN EN ISO 1183-1). The tensile strength is preferably 14 MPa (DIN 53504 / ISO 37). The elongation at break is preferably 550% (DIN 53504 / ISO 37), and the tear strength is preferably 38 N / mm² (DIN ISO 34-1, Method B(b) (Graves)). One such compound is available, for example, under the name Thermoplast ®< K, TF5TAA from the FC / AD1 / ht series of Kraiburg TPE GmbH & Co KG.

[0019] According to the invention, a method for manufacturing electrically insulating protective gloves with arc flash protection further comprises the step of dissolving the starting material in an organic solvent to produce a liquid mixture (in the sense of a solution).

[0020] The organic solvent is not fundamentally restricted according to the invention. However, according to a preferred embodiment, the organic solvent can be, in particular, toluene.

[0021] According to a further preferred embodiment, a liquid mixture of 10-50% w / w based on the proportion of the starting material in the organic solvent, particularly preferably 20-35% w / w, can be produced in the step of dissolving the starting material in the organic solvent. The proportion of the starting material in the organic solvent influences the viscosity of the resulting mixture and thus provides a way to control the layer thickness of the material layer resulting from a dipping step in the dipping process described below. Likewise, the proportion of the starting material in the organic solvent influences the stability of the dispersion described below, so that the proportion can be adjusted according to the desired stability.

[0022] According to the invention, a method for manufacturing electrically insulating protective gloves with arc flash protection further comprises the step of dispersing a pigment in the liquid mixture to produce a dispersion. The pigment can be added during the dissolution process of the starting material. The pigment can be dispersed completely and efficiently. The resulting dispersion is stable for a period of 10 to 48 hours and is therefore sufficiently stable for the duration of the manufacturing process. In this way, consistent production quality of the protective gloves can be ensured.

[0023] According to a preferred embodiment, in the step of dispersing the pigment in the liquid mixture a dispersion of 0.5-10% w / m based on the proportion of the pigment in relation to the starting material can be produced, preferably 0.5-5% w / m, particularly preferably 0.5-2.5% w / m.

[0024] In principle, the technical requirements for the manufacture of protective gloves for electrical applications are so high that materials without polyisoprene-based polymer structures could not be used until now. However, the inventors have advantageously discovered that by coordinating the physicochemical and mechanical properties of the two thermoplastic elastomers, particularly the SEBS-based thermoplastic elastomers, together with the addition of the pigment in concentrations of 0.5–10% w / w, not only can the properties required for electrical, mechanical, and physicochemical protection be achieved, but also thermal protection. Thus, the protective gloves manufactured using the inventive method not only meet the requirements of protection classes 00 to 4 according to the common standards, but also provide arc flash protection in accordance with the protection classes described herein.

[0025] The pigment is copper phthalocyanine, an organic pigment. For example, copper phthalocyanine alpha stab. (CAS No.: 147-14-8) with a specific surface area of ​​62 m² / g and a density of 1.6 g / cm³ can be used as a pigment. This pigment is available in powder form, for example, under the name Heliogen® Blue K 6907 from BASF SE.

[0026] In the interest of sustainability, according to a preferred embodiment of the process, at least a portion of the starting material and pigment can be replaced by waste material generated in the process and / or protective gloves produced using the process. The protective gloves produced from TPEs and pigment can be dissolved in the organic solvent, as described herein, and reused without significantly losing their physical, chemical, and mechanical properties. In the case of partial substitution, starting material and pigment are added to the liquid dispersion according to the specifications described herein. In this way, the gloves, once produced and used, can be collected and used for the production of new gloves.The same applies to gloves that are generated during the production process and can be immediately reintroduced into the process, thus preventing solid waste. Especially in the manufacture of safety products, such as electrically insulating gloves with high technical requirements and a high rate of defective batches, the reuse of raw materials is of paramount importance.

[0027] According to the invention, a method for manufacturing electrically insulating protective gloves with arc flash protection further comprises the step of providing at least one mold suitable for manufacturing protective gloves. For example, a mold in the form of a fully anatomical model of a forearm with a hand is suitable for manufacturing protective gloves. In particular, two or more molds can also be used, for example, fully anatomical models of a right and a left forearm with a hand.

[0028] The material of the at least one mold is not fundamentally restricted according to the invention. The mold can, for example, be made of ceramic or metal; however, preferably the at least one mold is a ceramic mold.

[0029] The number of molds that can be used simultaneously for the production of electrically insulating protective gloves in the process according to the invention is not limited and will certainly depend on process-related capacities or be selected accordingly. For example, between 96 and 140 molds can be used simultaneously.

[0030] According to a preferred embodiment, the at least one mold can have a predetermined surface finish. The haptics of the electrically insulating protective gloves can be specifically adjusted via the surface finish of the mold. In particular, the surface of the at least one mold can be smooth or rough. The term "rough" is to be interpreted broadly here. The term "rough" can, for example, be understood as sandpaper-like or abrasive-like. In this sense, the surface finish of the at least one mold can also have different degrees of roughness, corresponding, for example, to a grain size in the range of > 600 µm to 18 µm. In other words, the surface finish of the at least one mold can have a surface finish selected from the group consisting of smooth, very finely roughened, finely roughened, medium roughened, and coarsely roughened.

[0031] Prior to carrying out the dipping process described below, the procedure can optionally include the additional step of conditioning the viscosity, solids content, and / or temperature of the dispersion. In other words, the viscosity, solids content, and / or temperature of the dispersion can be adjusted according to the prevailing process conditions, such as ambient temperature and humidity, to ensure consistent quality of the manufactured protective gloves. Preferred ranges might include, for example, viscosity: 10⁻⁸ s, preferably 10⁻⁶ s, measured at 25 ± 1 °C using the Ford cup method; dry matter content: 20–45% w / w; and temperature: 20–30 °C.

[0032] The process may also optionally include the additional step of preparing the at least one mold, comprising the steps of: i) cleaning the at least one mold, for example with toluene; ii) applying a release agent, for example petroleum naphtha; and iii) conditioning the at least one mold for the dipping process.

[0033] Depending on the material and nature of at least one mold, applying a release agent can facilitate the subsequent removal of the manufactured protective gloves.

[0034] The process can also optionally include the additional step of preparing a tank for the immersion process. According to the invention, the size of the tank is not fundamentally limited and will generally depend on the given process-related capacities, for example, the number of molds used.

[0035] According to the invention, a method for producing electrically insulating protective gloves with arc flash protection further comprises the step of performing a dipping process. A dipping process comprises at least one cycle consisting of a dipping step in which, during an immersion phase, the at least one mold is completely immersed in the dispersion and, during a withdrawal phase, is completely removed from the dispersion to form a material layer on the mold; and a drying step to remove the organic solvent from the material layer.

[0036] The described immersion process is a purely physical immersion process. This means that no thermal or chemical process is necessary for the immersion, such as thermosensitive immersion or the addition of coagulants, thus advantageously reducing energy consumption and the use of chemical components in the manufacturing process.

[0037] According to a preferred embodiment, the dipping process can consist of 1-50 cycles, preferably 5-20 cycles. The wall thickness of the protective gloves can advantageously be adjusted by the number of cycles, since in each cycle another layer of material is formed superimposed on the at least one mold. Furthermore, the thickness of the individually formed material layers can also be controlled by the dipping speed.

[0038] According to a further preferred embodiment, in the immersion step the at least one mold can be immersed in the dispersion at a predetermined speed during the immersion phase and removed from the dispersion at a predetermined speed during the immersion phase.

[0039] According to a further preferred embodiment, the at least one mold can be constantly rotated during the drying step. This enables a uniform distribution of the material mixture on the surface of the mold and thus the formation of a uniformly thick material layer.

[0040] According to a particularly preferred embodiment, the at least one mold can be rotated at a predetermined speed and / or rotational velocity during the drying step. The rotational velocity can be, for example, 20-30 s / revolution, preferably 25 s / revolution.

[0041] According to a further preferred embodiment, the drying step can be carried out for a duration of 20-60 min.

[0042] The inventive method for producing electrically insulating protective gloves with arc flash protection can optionally further include the step of evaporating remaining solvent residues after the dipping process.

[0043] And the inventive method for producing electrically insulating protective gloves with arc flash protection further comprises the step of removing the protective glove thus formed from the at least one mold.

[0044] According to a preferred embodiment, the process according to the invention can be carried out without vulcanization. This is because the thermoplastic elastomers (TPEs) used in the process exhibit the viscoelastic properties typical of elastomers, without requiring vulcanization. Eliminating the vulcanization process offers the advantage of eliminating the energy typically required to generate pressure and temperature in an autoclave. Therefore, since the vulcanization process is omitted, the energy consumption in the process according to the invention is significantly lower compared to conventional processes that include vulcanization.

[0045] The elimination of vulcanization has the additional advantage that, since the material does not have typical cross-linking compounds, it can be easily reused and processed to regain its original shape or to create new products, either by heat forming or by re-dissolving it in organic solvent, as is used for the manufacture of the protective gloves described herein.

[0046] The invention described herein further relates to an electrically insulating protective glove with arc flash protection. The electrically insulating protective glove with arc flash protection consists essentially of two thermoplastic elastomers based on styrene-ethylene-butylene-styrene (SEBS) and an organic pigment, copper phthalocyanine, as described herein.

[0047] According to a preferred embodiment, the protective glove may further consist of a styrene-based polymeric auxiliary component, as described herein.

[0048] According to a further preferred embodiment, the electrically insulating protective glove with arc flash protection can also meet the requirements of protection classes 00 to 4 according to IEC 60903:2014. Reference to the currently valid standard IEC 60903:2014 does not preclude the possibility of meeting the requirements of future amendments to this standard. The electrically insulating protective glove with arc flash protection also fulfills the requirements for arc flash protection according to the protection classes described herein. The electrically insulating protective glove is obtainable by the inventive method described herein. BRIEF DESCRIPTION OF THE FIGURES

[0049] Figure 1Figure 1 shows the result of a tensile strength test on a protective glove made of TPEs and pigment using the inventive method (Jung Gummitechnik internal laboratory). The curve corresponds to the stress at elongation under the conditions described in the IEC 60903:2014 standard. Figure 2 Figure 1 shows the result of an investigation of the arc flash protection of protective gloves of class 00 to class APC 1 on protective gloves made of TPEs and pigment produced using the inventive method (standard test according to IEC 61482 - 1-2, tested at West Energie in Dortmund). DETAILED DESCRIPTION OF PREFERRED EXAMPLES

[0050] Examples and embodiments of the present invention are described below with reference to the accompanying figures.

[0051] It should be emphasized that the present invention is in no way limited or restricted to the embodiments and their features described below, but also includes modifications of the embodiments, in particular those which are covered by modifying the features of the described examples or by combining one or more features of the described examples within the scope of protection of the claims.

[0052] A first embodiment of the present invention is described in more detail below. The inventive method for manufacturing electrically insulating protective gloves with arc flash protection is based on a dipping process without a vulcanization process, in which the dipping step is purely physical, i.e., a mold is dipped into a dispersion at least once and then withdrawn.

[0053] In this first embodiment, the starting material for the production of the electrically insulating protective gloves with arc flash protection is a compound of two SEBS-based thermoplastic elastomers and a styrene-based polymeric auxiliary component, preferably Thermoplast ®< K TF5TAA from the FC / AD1 / ht series of the manufacturer Kraiburg TPE GmbH & Co KG.

[0054] The starting material is a solid mixture and is dissolved in toluene, whereby a liquid mixture, a solution, of 10-50% w / w based on the proportion of the starting material in toluene, particularly preferably 20-35% w / w, is produced.

[0055] The organic blue pigment copper phthalocyanine, preferably Heliogen® Blue K 6907 from BASF SE, is dispersed in the liquid mixture (solution), producing a dispersion of 0.5–10% w / w based on the proportion of the blue pigment relative to the starting material, preferably 0.5–5% w / w, and particularly preferably 0.5–2.5% w / w. The pigment can be added and dispersed while the starting material is dissolving in toluene. The dispersion is stable for 10–48 hours. "Stable" here means that the dispersion does not separate into its components, i.e., that the pigment does not settle.

[0056] Subsequently, a tank for the immersion process is prepared and made available, into which the dispersion is placed. Likewise, at least one ceramic mold in the form of a fully anatomical model of a forearm with hand is prepared and made available. This ceramic mold can first be cleaned with toluene, then petroleum ether can be applied as a release agent, and finally, the ceramic mold can be conditioned in the immersion machine intended for the process. Depending on the desired feel of the electrically insulating protective gloves, the surface of the ceramic mold can be rough or smooth, as described.

[0057] The produced dispersion can be further conditioned with regard to viscosity, solid mass and / or temperature before the immersion process, as already described.

[0058] Then one or more immersion parameters are defined for the immersion process, i.e., for example, the number of cycles, the speed of immersion of the mold into the dispersion, the speed of withdrawal of the mold from the dispersion, the number of revolutions with which the mold is to be rotated during the drying process, and the drying time between the immersion steps.

[0059] In this first embodiment, the immersion process consists of 10 cycles, each comprising an immersion step in which, during the immersion phase, the mold is completely immersed in the dispersion and, during the expulsion phase, the mold is completely removed from the dispersion to form a layer of material on the mold; and a drying step to remove the toluene from the layer of material.

[0060] The drying step is carried out for 30 minutes between each immersion step, during which the ceramic mold is constantly rotated. This means that once the ceramic mold has been removed from the dispersion, for example, by 180° around its longitudinal axis, it is rotated continuously to achieve a uniform surface distribution of the material. The number of rotations during the drying time depends, among other things, on the viscosity of the dispersion and the temperature. In this embodiment, the mold is rotated at a speed of 25 seconds per revolution, preferably at ambient temperature, for example, between 16°C and 30°C.

[0061] After the dipping process, the mold, now coated with several overlapping layers of material, is removed from the dipping system and any remaining toluene is optionally evaporated, preferably at ambient temperature, for example between 20°C and 35°C.

[0062] The protective glove formed on the mold is then removed from the ceramic mold, for example manually.

[0063] The electrically insulating protective gloves with arc flash protection, manufactured in this way, now undergo cuff adjustment, testing of their electrical and mechanical properties, and quality assessment, for example, visually. Afterward, the gloves can be labeled and packaged.

[0064] The protective gloves produced using the inventive method can have a surface texture corresponding to that of at least one mold. The different surfaces of the protective gloves each enable more specific tasks to be performed. For example, the roughness improves grip and thus allows certain tasks to be carried out that would be difficult with smooth gloves.

[0065] Furthermore, the protective gloves produced using the inventive method meet the standard requirements corresponding to protection classes 00, 0, 1, 2, 3 and 4, i.e., maximum operating voltages of 500 V to 36,000 V and test voltages of 2,500 V to 40,000 V.

[0066] In a second embodiment, waste material generated in the process and / or recycled protective gloves produced by the process are used instead of the starting material and pigment described in the first embodiment; for example, the protective gloves produced according to embodiment 1. In this case, the starting material and pigment can then be wholly or partially replaced by the waste material and / or the gloves produced by the process by dissolving or dispersing the waste material and / or the gloves in toluene. In the case of partial replacement, the starting material and pigment are added to the liquid dispersion according to the areas described herein. The subsequent process steps are the same as already described herein in embodiment 1.

[0067] The use of the material in the dissolution steps for the new glove production process was extensively tested, and the results are excellent. Even after multiple reuse steps, the manufactured gloves show no loss of relevant properties – neither electrical, mechanical, nor physicochemical.

[0068] Table 2 below shows the results of comparative tests on protective gloves made of pure natural rubber (average values ​​of products available on the market), on electrically insulating protective gloves with arc flash protection according to the invention made of new TPE material and pigment (as described, for example, in embodiment 1 with a proportion of 0.5% pigment based on the TPE mass), and on electrically insulating protective gloves with arc flash protection according to the invention made of recycled material (produced from internal rejects, as described, for example, in embodiment 1 with a proportion of 0.5% pigment based on the TPE mass).

[0069] As can be seen from the data in Table 2, both the electrically insulating protective gloves according to the invention made from new TPE material and pigment, and the electrically insulating protective gloves according to the invention made from recycled material, meet the requirements of the IEC 60903:2014 standard. Furthermore, the properties of the electrically insulating protective gloves according to the invention are in some respects even better than those of conventional electrically insulating protective gloves made from natural rubber. Table 2: Results of comparative studies (Jung Gummitechnik internal laboratory) product Sample thickness (mm) Tensile strength (N / mm²) Elongation at break (%) Stress at 100% (N / mm²< ) Penetration force (N) Permanent elongation (%) Standard IEC 60903:2014 <1,00 > 16 >600 >18 <15 natural rubber 1,00 17,6 885 0,660 40,4 1,0 new TPE material and pigment 1,00 17,7 666 0,781 75,3 2,0 recycled material 0,95 17,8 700 0,838 79,7 1,7

[0070] Figure 1 Furthermore, the behavior of an approximately 0.5 mm thick sample made of the inventive material consisting of TPEs and pigment with a pigment content of 0.5% of the TPE mass is shown during a tensile strength test. This test provides information about tensile strength and elongation.

[0071] The test consists of preparing the specimen to the desired thickness in the format described in standard IEC 60930. After being placed in the test fixture, the specimen is subjected to elongation until it breaks. The maximum tensile strength and the elongation of the specimen until breakage (fracture, see [reference]) are then recorded. Figure 1 ) recorded.

[0072] A good viscoelastic material is characterized by a balanced relationship between tensile strength and elongation. In polymeric compounds resulting from the combination of different polymeric structures, such a property can be achieved through a balance between the polymers used. The presence of poorly dispersed substances can significantly impair the achievement of a good balance of properties. The behavior observed in the sample shows that the material exhibits lower tensile strength and higher elongation at the beginning of the force application, which is typical for elastomers; shortly before the sample breaks, the curve rises to higher values ​​for tensile strength. The relationship between tensile strength and elongation is therefore balanced in the glove material according to the invention.

[0073] Currently, arc flash tests are not yet fully adapted to the requirements for the use of protective gloves, which means there is no specific standard for certification. However, the test principle GS-ET-42-1 exists for determining the protective potential of gloves against arc flashes. This method uses the basic system characteristics of the directed exposure of the box test procedure according to IEC 61482-1-2. The results are classified into classes, which are defined, among other things, by the arc flash current in kA, the arc flash duration in ms, the mean arc flash energy in kJ, and the mean ambient energy in kJ / m². The distance of the samples from the arc flash is 300 mm. The class divisions are as follows: Class 1 (Arc Protection Class, APC 1): 4 kA, 500 ms, 168 kJ; Class 2 (APC 2): 7 kA, 500 ms, 320 kJ.The durability consists in the fact that none of the tested gloves may exhibit an afterburn time > 5 s, melting to the inside, hole formation or exceeding the limit values ​​for skin burns according to the Stoll / Chianta criterion, as specified in the standard on which this method is based (IEC 61482 - 1-2).

[0074] The permissible energy limit curve is in Figure 2 The solid line represents the energy measured by the curves; the other curves (dotted, dashed, and dash-dotted) refer to the energy observed in the respective sensors under the respective gloves tested. Three Class 00 protective gloves, approximately 0.5 mm thick, were tested. The three protective gloves consisted of a material according to the invention, made of TPEs and pigment with a pigment content of 0.5% of the TPE mass, and were from three different batches. Figure 2Each of the curves (dotted, dashed and dash-dot) corresponds to the measurement result on a glove.

[0075] The protective gloves that are the subject of the present invention and can be manufactured using the inventive method correspond at least to the described class 1. Depending on the thickness of the protective gloves, however, higher protection classes for arc flash protection can be achieved.

[0076] The invention has numerous advantages.

[0077] The inventive method enables, for the first time, the use of TPEs as an alternative to conventional materials used to date for the production of electrically insulating protective gloves.

[0078] Due to the use of TPEs and the resulting obsolescence of vulcanization, the gloves do not contain sulfur-based allergens, as crosslinking additives such as sulfur or sulfur donors can be omitted.

[0079] Unlike natural rubber, TPEs do not contain any allergy-triggering proteins as components.

[0080] The product (electrically insulating protective glove with arc flash protection) does not undergo any thermal process (thermosensitive dipping, vulcanization) during manufacturing, making the process energy efficient.

[0081] Due to the non-chemical change in the materials resulting from the omission of the vulcanization process (the polymer chains are not cross-linked), the gloves produced in the inventive process can be dissolved again in organic solvent and used for the production of new gloves.

[0082] The protective gloves produced using the inventive method meet the technical requirements of standard IEC 60903, as confirmed by tests carried out in the AITEX certification laboratory in Spain (see also Figure 1and Table 2). In particular, the combination of the polymer mixture with the pigment offers additional protection against arcing according to the standard tested in accordance with IEC 61482-1-2, tested at West Energie in Dortmund (see Figure 2 ).

[0083] The protective gloves produced using the inventive method can have both a smooth and a rough surface, which allows adaptation to correspondingly specific activities.

[0084] Furthermore, according to IEC 60903, the protective gloves produced using the inventive method are resistant to ozone, acid and extremely low temperatures.

Claims

1. A method of manufacturing electrically insulating protective gloves with arc fault protection, characterized in that the method comprises the steps of: - providing a starting material essentially consisting of two thermoplastic elastomers; - dissolving the starting material in an organic solvent to produce a liquid mixture; - dispersing a pigment in the liquid mixture to produce a dispersion; - providing at least one mold suitable for manufacturing protective gloves; - carrying out a dipping process comprising at least one cycle consisting of: • a dipping step in which, in an immersion phase, the at least one mold is completely immersed in the dispersion and, in a withdrawal phase, is completely withdrawn again from the dispersion to form a material layer on the mold; and • a drying step to remove the organic solvent from the material layer; - optionally, evaporating remaining solvent residues after the dipping process; and - removing the protective glove thus formed from the at least one mold, characterized in that the two thermoplastic elastomers are based on styrene-ethylene-butylene-styrene (SEBS) and the pigment is an organic pigment, Cu-phthalocyanine.

2. The method according to claim 1, characterized in that the starting material additionally consists of a polymeric auxiliary component based on styrene.

3. The method according to at least one of claims 1 to 2, characterized in that the organic solvent is toluene.

4. The method according to at least one of claims 1 to 3, characterized in that a liquid mixture of 10-50% m / m based on the proportion of the starting material in the organic solvent is produced.

5. The method according to at least one of claims 1 to 4, characterized in that a dispersion of 0.5-10% m / m based on the proportion of the pigment in relation to the starting material is produced.

6. The method according to at least one of claims 1 to 5, characterized in that the method is carried out without vulcanization.

7. The method according to at least one of claims 1 to 6, characterized in that the dipping process consists of 1-50 cycles.

8. The method according to at least one of claims 1 to 7, characterized in that, in the dipping step, the at least one mold is dipped into the dispersion at a predetermined speed in the immersion phase and is withdrawn from the dispersion at a predetermined speed in the withdrawal phase.

9. The method according to at least one of claims 1 to 8, characterized in that, in the drying step, the at least one mold is constantly rotated.

10. The method according to claim 11, characterized in that the at least one mold is rotated at a predetermined rotational frequency and / or rotational speed.

11. The method according to at least one of claims 1 to 10, characterized in that the drying step is carried out for a period of 20-60 minutes.

12. The method according to at least one of claims 1 to 11, characterized in that at least part of the starting material and the pigment is replaced by waste material generated in the method and / or protective gloves manufactured using the process.

13. The method according to at least one of claims 1 to 12, characterized in that the at least one mold has a predetermined surface condition, in particular a smooth surface or a rough surface.

14. An electrically insulating protective glove with arc fault protection, characterized in that the protective glove essentially consists of two thermoplastic elastomers based on styrene-ethylene-butylene-styrene (SEBS) and an organic pigment, Cu-phthalocyanine.

15. The protective glove according to claim 14, characterized in that the protective glove additionally consists of a polymeric auxiliary component based on styrene.

16. The protective glove according to claim 14 or 15, characterized in that the electrically insulating protective glove with arc fault protection meets the requirements of standard classes 00 to 4 according to IEC 60903:2014.