Thermosetting reactive resin mixture

Abstract

The present invention relates to a thermosetting reactive resin mixture suitable as an impregnation or encapsulation material for coils, stators and rotors of electric engines, comprising: a) a polyfunctional isocyanate, b) an epoxy resin composition mainly comprising a compound A based on a glycidyl ether of an aliphatic and / or cycloaliphatic alcohol having at least two alcohol functional groups or a compound B based on a glycidyl ester of an aliphatic and / or cycloaliphatic carbonic acid having at least two carboxylic acid functional groups, and c) a curing accelerator, the curing accelerator being based on a boron trichloride-amine complex.

Description

[Technical field]

[0001] The present invention relates to a two-component thermosetting reactive resin mixture suitable for impregnation or encapsulation materials for coils, stators, and rotors of electric engines, the reactive resin mixture comprising a polyfunctional isocyanate and a polyepoxide resin. The conventional two-component reactive resin mixture is curable under heat in the presence of a curing accelerator such as a catalyst. [Background technology]

[0002] The state of the art (e.g., US Pat. No. 5,399,633) teaches that the molar ratio of polyepoxide resin to polyisocyanate may play a role in dimensional heat stability and on mechanical properties. For example, the molar ratio can be less than 1, and the reaction resin mixture is crosslinked in the presence of a curing catalyst at a temperature range of 70-130° C., and then post-cured at a temperature of up to 220° C. The resulting product exhibits good dimensional heat stability, but has poor mechanical properties and inadequate temperature cycle resistance. This can be solved by making the molar ratio greater than 1, or by adding a flexibilising or elastifying agent to the reaction mixture. Its viscosity is often difficult to manage.

[0003] Conventionally, polyepoxide resins of known two-component reactive resin mixtures are mainly based on aromatic reactive epoxy resins, such as DGEBA (diglycidyl ether of bisphenol A). The end products are limited by their mechanical properties, in particular with regard to tensile elongation at break and ultimate tensile strength.

[0004] A two-component thermosetting reactive resin mixture can be used in an encapsulated rotor as described in US Pat. No. 6,399,633, which discloses a product that exhibits cracking under certain conditions.

[0005] There is therefore a need to provide improved two-component thermosetting reactive resin mixtures suitable as impregnation or encapsulation materials for coils, stators and rotors of electric engines by ensuring adequate mechanical properties, in particular with regard to tensile elongation at break and ultimate tensile strength. Such systems / reactive mixtures must also be (thermo)mechanically efficient (without forming cracks) when used in filled systems and / or in the presence of toughening agents.

[0006] Patent Document 3 discloses a thermosetting composition comprising a polyisocyanate, a triglycidyl ether of trimethylolpropane, and a lithium chloride (LiCl) solution, which is used as a trimerization catalyst composition. The LiCl used as a curing accelerator immediately initiates the curing of the resin composition, so that the composition cannot be homogenized, degassed, and coated as required for the impregnation and encapsulation processes.

[0007] However, the impregnation and encapsulation processes require that the resin does not start to cure at moderate temperatures (up to 80° C.). In other words, before the curing step carried out in the impregnation and encapsulation processes, the mixture of all the components of the resin needs some latency at moderate temperatures (up to 80° C.) so that the composition can be homogenized, degassed, and coated. Therefore, the latency of the resin composition at moderate temperatures, which allows the composition to be homogenized, degassed, and coated, is a necessary condition to be met. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US 4,631,306 [Patent Document 2] DE 10 2018 125 567 [Patent Document 3] WO2017 / 025213

[0009] The object of the present invention is to overcome the above mentioned drawbacks by providing a thermosetting reactive resin mixture (referred to in the present application as "2K resin system") suitable as an impregnation or encapsulation material for coils, stators and rotors of electric engines, which reactive resin mixture has the following properties: a) polyfunctional isocyanates, b) an epoxy resin composition comprising mainly a compound A based on a glycidyl ether of an aliphatic and / or cycloaliphatic alcohol having at least two alcohol functional groups or a compound B based on a glycidyl ester of an aliphatic and / or cycloaliphatic carbonic acid having at least two carboxylic acid functional groups, c) a curing accelerator; Includes.

[0010] The use of the aliphatic (cycloaliphatic) epoxy resin composition as described above allows the improvement of 2K resin systems by increasing the tensile properties (tensile ultimate strength and tensile elongation at break) and, when filled, also the toughness (K1c and G1c) of the cured 2K resin system. This leads to an increase in crack resistance, which is in high demand in the electric vehicle market to produce crack-resistant rotors for electric motors. The aliphatic (cycloaliphatic) epoxy resin composition as described above is also suitable for impregnation and encapsulation processes, since the medium temperature latency of the epoxy composition avoids the composition from starting to cure during the homogenization, degassing and coating steps. The term "latency" refers to the viscosity of the epoxy composition. The term "medium latency" according to the present invention refers to the viscosity of the epoxy composition measured after the homogenization and degassing steps. The viscosity of the epoxy composition measured after the homogenization and degassing steps is compared to the viscosity of the epoxy composition measured immediately after mixing all the components of the composition together, and the viscosity of the epoxy composition measured immediately after mixing is also referred to as the initial viscosity of the epoxy composition. According to the present invention, an epoxy composition is recognized as having medium potential if its viscosity measured after the homogenization and degassing steps is less than twice the initial viscosity of the epoxy composition. The viscosity of the epoxy composition is measured according to ISO 2884 with a Brookfield CAP2000+ viscometer. According to a preferred embodiment, the epoxy resin composition comprises (mainly) butanediol diglycidyl ether, hexanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, neopentyl glycol diglycidyl ether, or a mixture thereof.

[0011] According to an advantageous embodiment of the present invention, the equivalent ratio of the isocyanate groups of the polyfunctional isocyanate, component (a), to the epoxide groups of the epoxy resin, component (b), is 10:1 to 1:1, preferably 5:1 to 3:1, which allows to increase the (thermo)mechanical effect of the 2K resin system of the present invention.

[0012] Furthermore, the polyfunctional isocyanate is preferably selected from the group including cycloaliphatic polyisocyanates, aromatic polyisocyanates, and mixtures thereof. The selection of the polyfunctional isocyanate, in combination with the selected epoxy resin composition of the present invention, can further increase the (thermo)mechanical properties of the 2K resin system.

[0013] In a particularly preferred embodiment of the present invention, the polyfunctional isocyanate is selected from the group comprising diphenylmethane-2,4- or -4,4'-diisocyanate; polyphenylenepolymethylene polyisocyanates; diphenylmethane diisocyanates containing carbodiimide or uretonimide groups; modified polyisocyanates containing allophanate, urethane, biuret and / or uretidione groups; isocyanate-based prepolymers obtained by reaction of an excess of the above polyisocyanates with polyols; and mixtures thereof.

[0014] In an advantageous embodiment of the invention, the curing accelerator is based on boron trichloride-amine complexes, preferably selected from the group comprising boron trichloride-dimethyloctylamine complex, boron trichloride-trimethylamine complex, boron trichloride-benzyldimethylamine complex, boron trichloride-tributylamine complex, and mixtures thereof, which allows the composition to have latency at moderate temperatures during the homogenization, degassing and coating steps.

[0015] According to a preferred embodiment, the hardening accelerator is present in an amount of 0.01 to 5 wt%, preferably 0.05 to 2.5 wt%, based on the total weight of the mixture.

[0016] The reactive resin mixture according to the invention is preferably anhydride-free.

[0017] Other embodiments of the reactive resin mixture of the present invention are mentioned in the accompanying claims.

[0018] The present invention also relates to a thermoset composition, obtainable by curing the reactive resin mixture according to the invention and as described above, which has a tensile elongation at break, measured according to ISO 527, of at least 4% and an ultimate tensile strength, measured according to ISO 527, of at least 95 MPa.

[0019] In a preferred embodiment, the thermoset composition is obtained by mixing the components of the mixture according to the invention and curing the resulting composition to give the thermoset composition of the invention. This embodiment corresponds to a cured 2K resin system obtained by crosslinking under heating. The terms "thermoset composition" and "cured 2K resin system" have the same meaning and can be used interchangeably.

[0020] Other embodiments of the thermosetting composition of the present invention are mentioned in the accompanying claims.

[0021] The present invention further relates to a process for providing a composite or cast article, the process comprising the steps of: a) mixing the components of the reactive resin mixture according to the present invention; b) applying the mixture to a textile or an electrical component; c) curing the applied mixture by applying a temperature comprised between 80°C and 250°C.

[0022] In a preferred embodiment, the process according to the invention further comprises the steps of: a1) mixing the components of the reactive resin mixture according to the invention; a2) homogenizing and degassing the mixture obtained in step a1) at a temperature of 20 to 60° C., preferably 30 to 50° C., for 5 to 100 minutes, preferably 30 to 60 minutes; b) applying the mixture to a textile or an electrical component; c) curing the applied mixture by applying a temperature of 80°C to 250°C. The process.

[0023] In a particularly advantageous embodiment of the invention, the fibres are selected from the group comprising glass fibres or carbon fibres.

[0024] In a preferred embodiment, the electrical component is selected from the group including coils, motors, stators, rotors, generator parts, printed circuit boards, car ignition coils.

[0025] Preferably, the impregnated fibers are formed into a composite article by using an infusion process, a wet compression molding process, a filament winding process, and / or a pultrusion process.

[0026] In a further preferred embodiment, the electrical component is impregnated with the mixture by dipping, trickle impregnation, vacuum pressure impregnation, and / or casting.

[0027] Further embodiments of the process of the invention are mentioned in the accompanying claims.

[0028] The present invention also relates to an article obtainable by carrying out the steps of mixing the components of the reactive resin mixture according to the invention, adding to said mixture at least one inorganic filler or metal powder, and curing the resulting composition in order to provide an article, in which the inorganic filler is preferably selected from the group comprising silica, fused silica, fumed silica, alumina, wollastonite, aluminium trihydroxide, magnesium hydroxide, AlO(OH), silicium carbide, boron nitride, calcium carbonate, aluminosilicates, glass powders, and mixtures thereof.

[0029] Preferably, the filler is a silanized filler, preferably a silanized amorphous silica.

[0030] More preferably, the articles of the invention have an ultimate tensile strength, measured according to ISO 527, of at least 76 MPa and a plane strain fracture toughness (K1c) of at least 3.0 MPa m 1 / 2 and in which at least one toughening agent is added to the mixture prior to curing, the toughening agent being selected from the list including core-shell rubber, polyacrylate, carboxyl-terminated butadiene acrylonitrile (CTBN) rubber, styrene butadiene rubber (SBR), phenoxy toughening agents, silicon block copolymer toughening agents.

[0031] This embodiment is particularly advantageous in terms of toughness (K1c and G1c) of the cured 2K resin system when filled with the compound(s) described above, which leads to increased crack resistance, which is in high demand in the electric vehicle market to produce crack resistant rotors for electric motors.

[0032] Other embodiments of the article of the invention are mentioned in the accompanying claims.

[0033] The present invention also encompasses encapsulation materials for electrical components, such as coils, stators and rotors, which materials comprise a composition according to the present invention or an article as defined herein.

[0034] The present invention provides 2K resin systems that exhibit exceptional thermomechanical properties compared to similar state-of-the-art resin systems, especially when filled with inorganic fillers and toughened with, for example, core-shell rubber tougheners.

[0035] The present invention relates to a two-component resin system based on a polyfunctional isocyanate (e.g., MDI-based resin, in which case the polyfunctional isocyanate can be Suprasec 2029 or Suprasec 2021) and an epoxy resin composition, preferably an aliphatic reactive epoxy diluent, such as butanediol diglycidyl ether (Araldite DY-D) or hexanediol diglycidyl ether (Araldite DY-H). In addition, at least one curing accelerator, such as a boron trihalide-amine complex (boron trichloride-dimethyloctylamine complex-Accelerator DY9577 or boron trichloride-trimethylamine), is used.

[0036] When mixing the polyfunctional isocyanates with the epoxy resins, temperatures in the range of 18-60°C can be preferentially applied. This also applies to filled systems. In this step, it is desirable to avoid any pre-reaction between the polyfunctional isocyanates and the epoxy resins.

[0037] With regard to curing of the reactive resin mixture, which must now take place as a reaction between the polyfunctional isocyanate and the epoxy resin, this process step can advantageously take place at a gelling temperature of 40-100°C, preferably 40-90°C, and post-curing can take place at a temperature of 100-180°C, preferably 110-150°C.

[0038] For curing of filled 2K systems, this process step can occur at a gel temperature of 40-100°C, preferably 40-90°C, and the post-cure can occur at a temperature of 100-180°C, preferably 110-150°C.

[0039] By replacing the aromatic epoxy resin with an aliphatic epoxy resin, the tensile properties (strength and elongation) and toughness (K1c and G1c) of the cured resin increase significantly.

[0040] The filled 2K resin systems of the present invention are preferably used in the rotors, stators and coils of electric engines.

[0041] The 2K resin system can be used in any product involving an impregnation / encapsulation process.

[0042] In a particularly preferred embodiment of the invention, materials made using the 2K resin system will have an isocyanurate lattice structure in which the molar ratio of oxazolidinone rings to isocyanurate rings is between 0.5 and 1.5.

[0043] The following examples illustrate the invention without limiting its scope. EXAMPLES

[0044] Example Section 1 Example 1 is obtained by carrying out the following steps: 200g Suprasec 2029, 40g Araldite DY-H, and 2g Accelerator DY 9577 are homogenized and degassed under stirring at 40°C for 1 hour. The mixture is then poured into a hot aluminum mold preheated to 80°C to prepare 2mm and 4mm thick specimens for tensile testing, bend-notch testing, and dynamic mechanical analysis (DMA). The composition is cured in an oven at 120°C for 2 hours and 180°C for another 2 hours.

[0045] Example 2 corresponds to the process described in Example 1, except that Araldite DY-H is replaced by a molar equivalent of Araldite DY-D.

[0046] Example 3 corresponds to Example 1, except that Suprasec 2029 is replaced with a molar equivalent of Suprasec 2021.

[0047] Example 4 corresponds to Example 2, except that Suprasec 2029 is replaced with a molar equivalent of Suprasec 2021.

[0048] Example 5 corresponds to Example 3, except that 16 phr of Araldite DY-H is used instead of 20 phr.

[0049] The effect on mechanical properties of different aliphatic reactive epoxy diluents in combination with MDI-based multifunctional isocyanates (Suprasec 2021, Suprasec 2029) and the curing catalyst boron trichloride-dimethyloctylamine complex (Accelerator DY 9577) is shown in Table 1 below.

[0050] It was found that the replacement of the aromatic epoxy resin Araldite GY 250 with the aliphatic epoxy resins Araldite DY-D or Araldite DY-H resulted in a significant increase in tensile elongation, tensile strength, and toughness (G1c, K1c) without any detrimental effect on the glass transition temperature.

[0051] The same effect can be observed when using Suprasec 2021 instead of Suprasec 2029 and changing the stoichiometric ratio of isocyanate equivalents to epoxy equivalents from 4 / 1 to 5 / 1.

[0052] [Table 1-1] [Table 1-2]

[0053] Comparative Examples 1 to 3 Comparative Example 1 is obtained by carrying out the following steps: 200g Suprasec 2029, 52g Araldite GY250, and 2g Accelerator DY 9577 are homogenized and degassed with stirring at 40°C for 1 hour. The mixture is then poured into a hot aluminum mold preheated to 80°C to prepare 2mm and 4mm thick specimens for tensile testing, notch bending testing, and dynamic mechanical analysis (DMA). The composition is cured in an oven at 120°C for 2 hours and 180°C for another 2 hours.

[0054] Comparative Example 2 is carried out using the description of Comparative Example 1, except that Suprasec 2029 is replaced with a molar equivalent of Suprasec 2021.

[0055] Comparative Example 3 corresponds to Comparative Example 2, except that 20 phr of Araldite DY250 is used instead of 25 phr.

[0056] [Table 2]

[0057] Example Section 2 Example 6 is obtained by carrying out the following steps: 200 g Suprasec 2021, 42 g Araldite DY-H, and 2 g Accelerator DY 9577 are homogenized and degassed at 40° C. for 1 hour while stirring. Then, 194 g silica powder and 258 g wollastonite are added in portions within 20 minutes while stirring. The mixture is carefully degassed at 50° C. for 0.5 hours. After that, it is poured into a hot vacuum press preheated to 120° C. to prepare 4 mm thick specimens for tensile testing, double torsion testing, and DSC. The composition is precured in the vacuum press at 120° C. for 30 minutes. After demolding, the composite plate is post-cured in an oven at 180° C. for another 2 hours.

[0058] Comparative Example 7 corresponds to Example 6, except that the Araldite DY-H is replaced by 6 phr of PARALOID pre-dispersed in 20 phr of Araldite DY-H.

[0059] Comparative Example 8 corresponds to Example 6, except that Araldite DY-H is replaced with 10 phr of PARALOID pre-dispersed in 16 phr of Araldite DY-D. The combined amount of silica powder and wollastonite is replaced with an equal weight of fused silica powder.

[0060] In a second embodiment of the present invention, it can be shown that the above resin system (e.g., Example 1) when filled with inorganic fillers exhibits exceptional thermomechanical properties compared to similar state-of-the-art resin systems, and even more advanced properties when further toughened, e.g., with a core-shell rubber toughener (Table 3).

[0061] Cured resins filled with inorganic fillers but not toughened exhibit exceptionally high toughness (K1c, G1c) combined with very high Tg > 200°C (Example 6). K1c exceeds or is at least on the same level as the state-of-the-art filled resins (Comparative Examples 4-6), with the big difference being that the latter can only achieve such high values ​​when significant amounts of toughening agents are incorporated.

[0062] Furthermore, when a toughening agent is incorporated into the neat resin matrix of the present invention, the toughness is outstandingly high, K1c 3.3-3.7 MPa m 1 / 2 (Examples 7 to 8). Furthermore, the ultimate tensile strength increases to a maximum of 97 MPa, and the tensile breaking elongation increases to a maximum of 1.7%.

[0063] [Table 3-1] [Table 3-2]

[0064] Comparative Examples 4 to 6 Comparative Example 4 in the table below corresponds to composition A1 disclosed in WO 2016202608, and this comparative example relates to the resin type cycloaliphatic epoxy / homopolymerization catalyst.

[0065] Comparative Example 5 relates to a cycloaliphatic epoxy / methyl naphthalene anhydride resin type and was obtained as follows:

[0066] Component A (i.e., the resin part) of Comparative Example 5 was prepared as follows: In a 2 liter ESCO mixer equipped with external heating and a speed disc for stirring, the following ingredients were added to the vessel at room temperature: 503.4 g Celloxide 2021 P, 4 g RPS 1312-1, 2.2 g Antischaum SH, 20 g Silan A-187. All ingredients were heated up to 50° C. under 10 mbar vacuum for 20 minutes while stirring at 700 rpm. Then, to the mixing vessel, 100 g Genioperl® P52, 200 g Amorphous Silica 2, 460 g Amorphous Silica 3, 670 g Wollastonite 1, and 9 g Bentone SD-2 were added in small portions while stirring (temperature decreased to 35-40° C.). The mixture was stirred (700 rpm) at 50° C. at 10 mbar for 40 minutes. Then, 4 g BYK W-9010 was added to the mixture. The mixture was stirred again for 30 minutes at 700 rpm and 10 mbar Finally, the mixture (component A) was cooled to 40° C. and discharged into a container.

[0067] Component B (i.e., the curing agent part) of Comparative Example 5 was prepared as follows: In a 2 liter ESCO mixer equipped with external heating and a speed disc for stirring, 522.4 ARADUR® HY 906 was added. The vessel was then heated to 75-80°C. 100 g Genioperl® W 35 was then added. The mixture was stirred at 75-80°C under vacuum (10-15 mbar) until the Genioperl® W 35 was completely dissolved in the ARADUR® HY 906 (very slightly cloudy liquid). It was then cooled to 50-55°C and 0.6 g Oracet blue 690 was added. The mixture was then stirred until a homogeneous blue liquid was visible. The vessel was then added at 50-55°C with 2.4 g DY 070, 10 g BYK W 980, 6.6 g BYK W 9010, and 1 g PE G200. The mixture was then stirred at 300 rpm under vacuum (10 mbar) at 55° C. for 20 minutes. The liquid was then stirred under vacuum (10 mbar) and the stirring speed was increased to 700 rpm while 520 g of amorphous silica 2, 820 g of wollastonite 1, and 10 g of Bentone SD-2 were added thereto. g were added in small portions. The temperature should rise to 55-60° C. within 20 minutes with stirring. The mixture was kept under stirring at 700 rpm and vacuum (10 mbar) without heating (the temperature of the vessel was 55-60° C.) for 20 minutes. Then 7 g of Aerosil R-202 were added to the mixture and stirred at 700 rpm at 55-60° C. for 10 minutes. The speed was then increased to 800 rpm for another 10 minutes. Finally, the mixture was cooled to 40-45° C. and discharged into a vessel.

[0068] Preparation of the final mixture of components A and B: 300 g of resin formulation (component A) and 405 g of hardener formulation (component B) were combined and heated to about 60° C. under vacuum with stirring at 100 rpm. A mold was preheated in an oven to about 120° C. to produce test plates with a thickness of 4 mm. The degassed resin / hardener mixture was then poured into the mold. The mold was then placed in an oven at 120° C. for 20 minutes, then heated to 190° C. and maintained at 190° C. for 3 hours. The mold was then removed from the oven and cooled to room temperature before being opened. The cured plates were subjected to various tests, the results of which are shown in Table 4.

[0069] Comparative Example 6 relates to cycloaliphatic epoxy / methyltetrahydrophthalic anhydride and is obtained as follows:

[0070] For component A, the same process as disclosed in Comparative Example 5. For component B of this Comparative Example 6, it was prepared as follows: In a 2 liter ESCO mixer equipped with external heating and a speed disc for stirring, 518.4 g of ARADURE® HY 918-1 was added. This was then heated to 75-80°C. 60 g of Genioperl® W 35 was then added. The mixture was stirred at 75-80°C under vacuum (10-15 mbar) until the Genioperl® W 35 was completely dissolved in the ARADURE® HY 918-1. This was then cooled to 50-55°C and a vessel was charged with 0.6 g of Oracet blue 690, 3 g of DY 070, 10 g of BYK W 980, 10 g of BYK 10 ... 7 g of W 9010 were added. The mixture was then stirred at 300 rpm at 55° C. under vacuum (10 mbar) for 20 minutes. 564 g of amorphous silica 2, 820 g of wollastonite 1 and 10 g of Bentone SD-2 were then added in portions while the liquid was stirred under vacuum (10 mbar) and the stirring speed was increased to 700 rpm. The temperature should rise to 55-60° C. within 20 minutes with stirring. The mixture was kept under stirring at 700 rpm and vacuum (10 mbar) without heating (the temperature of the vessel was 55-60° C.) for 20 minutes. 7 g of Aerosil R-202 were then added to the mixture and stirred at 700 rpm at 55-60° C. for 10 minutes. The speed was then increased to 800 rpm for another 10 minutes. Finally, the mixture was cooled to 40-45° C. and discharged into a vessel.

[0071] Preparation of the final mixture of A and B: 300 g of the resin formulation (Component A) and 375 g of the hardener formulation (Component B) were combined and heated to approximately 60° C. under vacuum with stirring at 100 rpm.

[0072] To produce test panels with a thickness of 4 mm, the mould was preheated in an oven to about 120°C. The degassed resin / hardener mixture was then poured into the mould. The mould was then placed in an oven at 120°C for 20 minutes, then heated to 190°C and held at 190°C for 3 hours. The mould was then removed from the oven and allowed to cool to room temperature before being opened. The cured panels were subjected to various tests, the results of which are shown in Table 4.

[0073] [Table 4]

[0074] Example Section 3 Example 9 corresponds to Example 3 and is obtained by carrying out the following steps: 200 g of Suprasec 2021, 40 g of Araldite DY-H, and 2 g of Accelerator DY 9577 are homogenized and degassed with stirring at 40° C. for 1 hour. The mixture is then poured into a hot aluminum mold preheated to 80° C. to prepare 2 mm and 4 mm thick specimens for tensile testing, notch bending testing, and dynamic mechanical analysis (DMA). The composition is cured in an oven at 120° C. for 2 hours and at 180° C. for another 2 hours.

[0075] Comparative Example 7 corresponds to Example 3, except that Accelerator DY 9577 is replaced by a 5 wt% LiCl solution in 2-methyl-1,3-propanediol. Comparative Example 7 is obtained by carrying out the following steps: 200 g Suprasec 2021, 40 g Araldite DY-H, and 0.87 g 5 wt% LiCl solution in 2-methyl-1,3-propanediol are homogenized and degassed under stirring for 1 hour at 40° C. However, after 15 minutes at 40° C., the composition containing 200 g Suprasec 2021, 40 g Araldite DY-H, and 0.87 g 5 wt% LiCl solution in 2-methyl-1,3-propanediol forms a gel and already starts to harden.

[0076] The initial viscosity (V0), the viscosity measured after 15 minutes at 40°C (V1), and the viscosity measured after 1 hour at 40°C (V2) of Example 9 and Comparative Example 7 are shown in Table 5.

[0077] [Table 5]

[0078] component Suprasec 2021: Diphenylmethane diisocyanate (MDI) based polyfunctional isocyanate with an NCO value of 23.2%. Supplier: Huntsman, USA. Suprasec 2029: Diphenylmethane diisocyanate (MDI) based polyfunctional isocyanate with an NCO value of 24.5%. Supplier: Huntsman, USA. Araldite GY250: Diglycidyl ether of bisphenol A, epoxy value 5.3-5.5 eq / kg. Supplier: Huntsman, USA. Araldite DY-D: Butanediol diglycidyl ether, epoxy value 8.0-8.5 eq / kg. Supplier: Huntsman, USA. Araldite DY-H: Hexanediol diglycidyl ether, epoxy value 6.5-7.0 eq / kg. Supplier: Huntsman, USA. Accelerator DY 9577: Boron trichloride amine complex. Supplier: Huntsman, USA. PARALOID: Methyl methacrylate butadiene styrene (MBS) core-shell rubber impact modifier. Supplier: Dow, USA. Silica powder: epoxy-silane coated filler with the following particle size distribution: D103μm, D5017μm, D9050μm. Supplier: Quarzwerke Group, Germany. Fused Silica Powder: Epoxy-silane coated filler with the following particle size distribution: D103μm, D5017μm, D9050μm. Supplier: Quarzwerke Group, Germany. Wollastonite: Calcium metasilicate (CaSiO3) with the following particle size distribution: D50 9-16 μm (79-89 wt% < 45 μm, 26-36 wt% < 4 μm, < 28 wt% < 2 μm). Supplier: Nordkalk Corporation, Finland. Amorphous Silica 2: Fused Silica, D10 2.5 μm, D50 20 μm, D90 50 μm, Supplier: Quarzwerke Group Frechen, Germany. Amorphous Silica 3: Epoxy-silane surface treated fused silica, D103μm, D5017μm, D9050μm, Supplier: Quarzwerke Group Frechen, Germany. Aerosil R-202: Hydrophobic fumed silica, Supplier: Evonik Industries AG, Essen, Germany. BYK W 9010: Rheology related additive (wetting agent), Supplier: Byk Additives and Instruments, Wesel, Germany. Wollastonite 1: Calcium metasilicate (CaSiO3) with the following specifications: particle size D50 9-16 microns (84±5wt% <45 microns, 26-36wt% <4 microns, <28wt% <2 microns); bulk density 0.88-0.97g / cm3; whiteness, Ry>85%; L / D ratio: 3:1; Supplier: Nordkalk Oy Ab, Pargas, Finland. Genioperl® W35: Block copolymer with silicone and organic blocks (caprolactone-based), supplier: Wacker Chemie AG, Munich, Germany. Genioperl® P52: core-shell particles with a silicone core and a PMMA shell, supplied by Wacker Chemie AG, Munich, Germany. ARADUR® HY 906 anhydride hardener, a mixture of 1-methyl-5-norbornene-2,3-dicarboxylic anhydride and 5-norbornene-2,3-carboxylic anhydride, supplied by Huntsman International LLC, The Woodlands, TX. ARALDITE® CY 179-1 (also sold as Celloxide 2021 P): 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, supplied by Huntsman Advanced Materials (Switzerland) GmbH, Basel, Switzerland. RPS 1312-1 Colorpaste (3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate with carbon black), supplied by Huntsman Advanced Materials (Switzerland) GmbH, Basel, Switzerland. Antischaum SH: Silicone-based antifoam, Supplier: Wacker Chemie AG, Munich, Germany. p.19p.20 SILAN A-187: gamma-glycidyloxypropyltrimethoxysilane, supplied by Momentive Performance Materials, Inc., Waterford, NY. Bentone SD®-2 organoclay for solvent-borne coatings, provided by the firm Elementis. Oracet blue 690 Anthrachinone type colorant, supplied by BASF Colors & Effects GmbH Ander Rheinschanze 1 67059 Ludwigshafen, GERMANY. Accelerator DY 070: 1-Methylimidazole, supplied by Huntsman International LLC, The Woodlands, TX. BYK W 980: Wetting and dispersing additive, supplied by BYK firm. PEG 200: CAS number, 25322-68-3. ARADUR® HY 918-1: Thermosetting anhydride fluid, source Huntsman International LLC, The Woodlands, TX.

[0079] As used herein, the singular forms "a," "an," and "the" include both singular and plural references unless the context clearly dictates otherwise. By way of example, "an isocyanate group" means "one isocyanate group or more than one isocyanate group."

[0080] The terms "comprising," "comprises," and "comprised of," as used herein, are synonymous with "including," "includes," or "containing," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps. It should be understood that the terms "comprising," "comprises," and "comprised of," as used herein, include the terms "consisting of," "consists," and "consists of." This means that preferably, the above terms such as "comprising", "comprises", "comprised of", "containing", "contains", "contained of" etc. can be replaced with "consisting", "consisting of" and "consists".

[0081] Throughout this application, the term "about" is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value.

[0082] As used herein, the terms "weight %", "wt%", "weight percentage", or "percentage by weight" are used interchangeably.

[0083] The recitation of numerical ranges by endpoints includes all integers and, where appropriate, fractions subsumed within that range (e.g., 1 to 5 can include 1, 2, 3, 4, for example, when referring to a number of elements, and can also include 1.5, 2, 2.75, and 30, 3.80, for example, when referring to a measurement). The recitation of endpoints also includes the endpoint values ​​themselves (e.g., 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all subranges subsumed therein.

[0084] All references cited herein are hereby incorporated by reference in their entirety. Specifically, the teachings of all references herein that are specifically mentioned are incorporated by reference.

[0085] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As a further guide, definitions of terms are included to better understand the teachings of the present invention.

Claims

1. 1. A thermosetting reactive resin mixture suitable as an impregnation or encapsulation material for coils, stators, rotors of electric engines, comprising: a) polyfunctional isocyanates, b) an epoxy resin composition comprising primarily a compound A based on a glycidyl ether of an aliphatic and / or cycloaliphatic alcohol having at least two alcohol functional groups, or a compound B based on a glycidyl ester of an aliphatic and / or cycloaliphatic carbonic acid having at least two carboxylic acid functional groups; c) curing accelerators based on boron trichloride-amine complexes; The reactive resin mixture comprising:

2. 2. The mixture of claim 1, wherein compound A or compound B is selected from the group consisting of butanediol diglycidyl ether, hexanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, neopentyl glycol diglycidyl ether, and mixtures thereof.

3. 3. The mixture of claim 1 or 2, wherein the equivalent ratio of isocyanate groups of component (a) to epoxide groups of component (b) is from 10:1 to 1:1, preferably from 5:1 to 3:

1.

4. 3. The mixture of claim 1 or 2, wherein the polyfunctional isocyanate is selected from the group comprising cycloaliphatic polyisocyanates, aromatic polyisocyanates, and mixtures thereof.

5. 3. The mixture of claim 1 or 2, wherein the polyfunctional isocyanate is selected from the group comprising diphenylmethane-2,4- or -4,4'-diisocyanate; polyphenylenepolymethylene polyisocyanate; diphenylmethane diisocyanate having carbodiimide or uretonimide groups; modified polyisocyanates having allophanate, urethane, biuret, and / or uretidione groups; isocyanate-based prepolymers obtained by reacting an excess of the polyisocyanate with a polyol; and mixtures thereof.

6. 3. The mixture of claim 1 or 2, wherein the curing accelerator based on a boron trichloride-amine complex is selected from the group comprising boron trichloride-dimethyloctylamine complex, boron trichloride-trimethylamine complex, boron trichloride-benzyldimethylamine complex, boron trichloride-tributylamine complex, and mixtures thereof.

7. 3. The mixture of claim 1 or 2, wherein the accelerator is present in an amount of 0.01 to 5 wt %, preferably 0.05 to 2.5 wt %, based on the total weight of the mixture.

8. A thermosetting composition obtained by curing the thermosetting reactive resin mixture according to claim 1 or 2.

9. 1. A process for providing a composite or cast article, comprising the steps of: a) mixing the components of the reactive resin mixture of claim 1 or 2; b) applying the mixture to a fiber or an electrical component; c) curing the applied mixture by applying a temperature comprised between 80°C and 250°C; The process comprising:

10. 10. The process of claim 9, wherein the fibers are selected from the group comprising glass fibers or carbon fibers, and / or the electrical components are selected from the group comprising coils, motors, stators, rotors, generator components, printed circuit boards, car ignition coils.

11. 10. The process of claim 9, wherein the impregnated fibers are formed into a composite article by using an infusion process, a wet compression molding process, a filament winding process, and / or a pultrusion process.

12. 10. The process of claim 9, wherein the electrical component is impregnated with the mixture by dipping, trickle impregnation, vacuum pressure impregnation, and / or casting.

13. 3. An article obtainable by mixing the components of the reactive resin mixture of claim 1 or 2, adding at least one inorganic filler or metal powder to the mixture, and curing the resulting composition to provide an article, wherein the inorganic filler is preferably selected from the group comprising silica, fused silica, fumed silica, alumina, wollastonite, aluminum trihydroxide, magnesium hydroxide, AlO(OH), silicium carbide, boron nitride, calcium carbonate, aluminosilicates, glass powders, and mixtures thereof.

14. 14. The article of claim 13, wherein the filler is a silanized filler, preferably a silanized amorphous silica.

15. An encapsulant for electrical components such as coils, stators, and rotors comprising the thermoset composition of claim 8.

16. An encapsulating material for electrical components such as coils, stators, and rotors, comprising the article of claim 14.