Two-component solvent-free organic silicon resin insulating paint as well as preparation method, use method and application thereof

Abstract

The invention belongs to the technical field of insulating materials, and relates to two-component solvent-free organic silicon resin insulating paint as well as a preparation method, a use method and application of the two-component solvent-free organic silicon resin insulating paint. The component A comprises MQ vinyl silicone resin, other vinyl silicone resin, phenyl-containing silicone resin, a flexibilizer, a coupling agent, a catalyst and an inhibitor, and the component B comprises hydrogen-containing silicone resin; mQ vinyl silicone resin and other vinyl silicone resin are selected for synergistic matching, and phenyl-containing silicone resin and the flexibilizer are introduced for modification, so that the heat resistance, the mechanical property and the adhesion property of the obtained organic silicone resin insulating paint are effectively improved, and an insulating paint film formed by the organic silicone resin insulating paint can resist the high temperature of 220 DEG C for a long time; the coating has excellent anti-cracking performance, high adhesive force and excellent comprehensive performance, avoids environmental protection and safety problems caused by solvent volatilization, and is environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of insulating materials technology, and relates to a two-component solvent-free organosilicon resin insulating varnish, its preparation method, usage method and application. Background Technology

[0002] Organosilicon resins are widely used as impregnating insulating varnishes for heat resistance grades of H (180℃) and above due to their excellent heat resistance, electrical insulation, weather resistance, and chemical stability. Their long-term operating temperature can reach 180~200℃, and they can withstand short-term temperatures above 250℃. They also exhibit stable performance under high and low temperature cycling, holding a core position in the field of insulating materials. As an impregnating insulating varnish, it is mainly used in high-end electrical equipment with extremely high requirements for heat resistance and reliability, such as high-temperature traction motors, new energy vehicle drive motors, special and high-performance motors, and dry-type transformers. In the production of coil windings, organosilicon resins are typically mixed with solvents such as toluene or xylene to a suitable viscosity. The pre-treated workpiece is then placed in impregnation equipment, and a normal pressure, vacuum, or vacuum pressure impregnation (VPI) process is used to allow the varnish to fully penetrate the gaps and capillaries of the insulation layer. Then, staged temperature-curing is performed, and the solvent must be allowed to evaporate fully during the low-temperature curing stage.

[0003] In the existing technology, silicone resin insulating varnish has a wide range of applications, but there are still many problems: (1) Limited heat resistance. Most conventional products can only maintain a long-term operating temperature of 180~200℃. In high-temperature environments of 220℃ and above, the resin is prone to thermal oxidation degradation, which leads to a rapid decline in insulation performance and a shortened service life; (2) Poor mechanical properties. Conventional silicone resin has a high crosslinking density and strong molecular chain rigidity, which leads to high brittleness of the cured product and insufficient impact strength and tensile strength; (3) Poor crack resistance. Under alternating hot and cold cycles or mechanical vibration conditions, microcracks are prone to appear due to insufficient flexibility, which in turn leads to insulation failure; (4) Some products have problems such as incomplete curing, poor compatibility, and poor storage stability due to improper raw material selection or unreasonable ratio, which affect the overall use effect; (5) During the mixing process, the solvent has the characteristics of high volatility, flammability and explosiveness, which not only affects the health of operators, but also poses safety risks and is not environmentally friendly. It is necessary to strictly regulate the production operation process.

[0004] Currently, methods to improve the heat resistance of silicone resins mainly involve introducing groups such as phenyl and trifluoropropyl groups; while improving flexibility often involves adding plasticizers or blending with flexible resins. However, these two methods often fail to achieve both heat resistance and flexibility simultaneously, and also suffer from problems such as poor compatibility between the components.

[0005] Therefore, in order to address the above problems, there is an urgent need to develop an organosilicon resin insulating varnish that combines excellent long-term heat resistance, crack resistance, good compatibility of each component, and is solvent-free. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a two-component solvent-free silicone resin insulating varnish, its preparation method, and its application method. The silicone resin insulating varnish, through optimization of the resin system composition and ratio, exhibits excellent heat resistance. After curing to form an insulating film, it can withstand high temperatures of 220°C for a long time, and also has excellent crack resistance and high adhesion. Its overall performance is excellent, and it is solvent-free and environmentally friendly.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides a two-component solvent-free silicone resin insulating varnish, wherein the two-component solvent-free silicone resin insulating varnish comprises component A and component B;

[0009] Component A comprises the following components in parts by weight:

[0010] MQ vinyl silicone resin 15~35 parts by weight;

[0011] Other vinyl silicone resins, 20-42 parts by weight;

[0012] Contains 8-15 parts by weight of phenyl silicone resin;

[0013] Toughening agent 3-16 parts by weight;

[0014] 1-3 parts by weight of coupling agent;

[0015] Catalyst: 0.02~0.08 parts by weight;

[0016] Inhibitor 0.004~0.08 parts by weight;

[0017] Component B comprises the following components in parts by weight:

[0018] 85-97 parts by weight of hydrogen-containing silicone resin.

[0019] The amount of MQ vinyl silicone resin used can be 15 parts by weight, 17 parts by weight, 19 parts by weight, 21 parts by weight, 23 parts by weight, 25 parts by weight, 27 parts by weight, 29 parts by weight, 31 parts by weight, 33 parts by weight, or 35 parts by weight, etc.

[0020] The amount of the other vinyl silicone resin can be 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, 40 parts by weight, or 42 parts by weight, etc.

[0021] The amount of the phenyl-containing silicone resin can be 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, or 15 parts by weight, etc.

[0022] The amount of the toughening agent can be 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, or 16 parts by weight, etc.

[0023] The amount of the coupling agent can be 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, or 3 parts by weight, etc.

[0024] The amount of catalyst used can be 0.02 parts by weight, 0.03 parts by weight, 0.04 parts by weight, 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, or 0.08 parts by weight, etc.

[0025] The amount of the inhibitor can be 0.004 parts by weight, 0.0045 parts by weight, 0.005 parts by weight, 0.0055 parts by weight, 0.006 parts by weight, 0.005 parts by weight, 0.007 parts by weight, 0.0075 parts by weight, or 0.008 parts by weight, etc.

[0026] The amount of the hydrogen-containing silicone resin can be 85 parts by weight, 87 parts by weight, 89 parts by weight, 91 parts by weight, 93 parts by weight, 95 parts by weight, or 97 parts by weight, etc.

[0027] For the two-component solvent-free silicone resin insulating varnish provided by this invention, MQ vinyl silicone resin and other vinyl silicone resins in component A serve as base resins, which can produce a synergistic effect to balance the viscosity and crosslinking density of the system. The addition of the phenyl-containing silicone resin, with its steric hindrance effect, can inhibit the thermal motion of molecular chains, significantly increasing the thermal decomposition temperature of the resin, thereby effectively improving the long-term high-temperature stability of the silicone resin insulating varnish. The addition of the toughening agent can effectively improve the crack resistance of the silicone resin insulating varnish. The siloxane groups in the coupling agent can crosslink with the silicone resin, significantly improving the adhesion and interfacial compatibility of the varnish film. The inhibitor can regulate the curing speed, preventing premature curing during construction. The hydrogen-containing silicone resin in component B acts as a crosslinking agent and undergoes a hydrosilylation reaction with the vinyl silicone resin; the high hydrogen content can improve the crosslinking efficiency and reduce the curing time.

[0028] In this invention, "other vinyl silicone resins" refers to other vinyl-containing silicone resins besides MQ vinyl silicone resin.

[0029] Preferably, the viscosity of the MQ vinyl silicone resin is 5000~12000 mPa·s, such as 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s or 12000 mPa·s.

[0030] In this invention, the viscosity of the MQ vinyl silicone resin is tested at 25°C, and can be specifically tested according to GB / T2794-2013 "Determination of viscosity of adhesives - single cylinder rotation viscometer method".

[0031] Preferably, the vinyl content in the MQ vinyl silicone resin is 1.5% to 2% by mass, such as 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%.

[0032] Preferably, the viscosity of the other vinyl silicone resin is 10~150 mPa·s, such as 10 mPa·s, 20 mPa·s, 30 mPa·s, 40 mPa·s, 50 mPa·s, 60 mPa·s, 70 mPa·s, 80 mPa·s, 90 mPa·s, 100 mPa·s, 110 mPa·s, 120 mPa·s, 130 mPa·s, 140 mPa·s, or 150 mPa·s.

[0033] In this invention, the viscosity of the other vinyl silicone resins is tested at 25°C, and can be specifically tested according to GB / T2794-2013 "Determination of viscosity of adhesives - single cylinder rotation viscometer method".

[0034] As a preferred technical solution of the present invention, the above-mentioned MQ vinyl silicone resin with a viscosity of 5000~12000 mPa·s is selected and combined with other vinyl silicone resins with a viscosity of 10~150 mPa·s. The two work together to ensure that the viscosity of the resulting organosilicon resin insulating varnish is moderate and the impregnation performance is excellent without the addition of solvents, which can effectively solve the problem of high viscosity that is common in solvent-free products.

[0035] Preferably, the other vinyl silicone resins contain 1 to 1.5% vinyl by mass, such as 1%, 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, or 1.5%.

[0036] Preferably, the phenyl-containing silicone resin contains 35-45% phenyl by mass, such as 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, or 45%. If the phenyl-containing silicone resin contains too much phenyl by mass, it will increase the viscosity of the system, reduce the fluidity of the resin system, and affect the processability. If the phenyl-containing silicone resin contains too little phenyl by mass, it will result in an insignificant improvement in heat resistance.

[0037] Preferably, the toughening agent comprises a blend of polyester-modified silicone resin and polyurethane acrylate-modified silicone resin; the blend of the two serves as a toughening agent, the former utilizing the flexibility of polyester segments to improve the impact resistance of silicone resin insulating varnish, and the latter enhancing the crack resistance of silicone resin insulating varnish through the elastic recovery of PUA segments. Both are silicone-modified and have excellent compatibility with the base resin (MQ vinyl silicone resin and other vinyl silicone resins), effectively preventing phase separation.

[0038] Preferably, the mass ratio of the polyester-modified silicone resin to the polyurethane acrylate-modified silicone resin is 1:(0.5~2), for example, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9 or 1:2, etc.

[0039] Preferably, the coupling agent includes γ-glycidoxypropyltrimethoxysilane, whose epoxy groups can react with the hydroxyl groups on the substrate surface, and whose siloxane groups can crosslink with the organosilicon resin, significantly improving adhesion and interfacial compatibility.

[0040] Preferably, the catalyst comprises a platinum catalyst; more preferably, it is a platinum-vinylsiloxane complex, which has the characteristic of higher catalytic efficiency.

[0041] Preferably, the inhibitor comprises alkynol compounds.

[0042] Preferably, the alkynol compounds include 1-ethynyl-1-cyclohexanol (ECH) and / or 2-methyl-3-butyn-2-ol (MBY).

[0043] Preferably, the viscosity of the hydrogen-containing silicone resin is 18~60 mPa·s, such as 18 mPa·s, 19 mPa·s, 20 mPa·s, 25 mPa·s, 30 mPa·s, 35 mPa·s, 40 mPa·s, 45 mPa·s, 50 mPa·s, 55 mPa·s, or 60 mPa·s.

[0044] Preferably, the hydrogen content in the hydrogen-containing silicone resin is 1 to 1.5% by mass, such as 1%, 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, or 1.5%.

[0045] Preferably, component B also includes an antioxidant, which can effectively inhibit the thermal oxidative degradation of the insulating varnish at high temperatures.

[0046] Preferably, the antioxidant content in component B is 0.2 to 1 part by weight, for example, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight.

[0047] Preferably, the antioxidant includes hindered phenolic antioxidants.

[0048] In a second aspect, the present invention provides a method for preparing a two-component solvent-free organosilicon resin insulating varnish as described in the first aspect, the method comprising the preparation of component A and component B;

[0049] The preparation method of component A includes: mixing MQ vinyl silicone resin, other vinyl silicone resins, phenyl-containing silicone resins, toughening agents, coupling agents, catalysts and inhibitors to obtain component A;

[0050] The preparation method of component B includes: mixing a hydrogen-containing silicone resin and optionally an antioxidant to obtain component B.

[0051] Preferably, the catalyst and inhibitor are mixed in the form of a premixed liquid, which can further ensure the accurate formulation ratio and guarantee the performance stability of the cured product.

[0052] For example, the catalyst and inhibitor in an appropriate proportion can be pre-dispersed with 10 to 20 times the amount of vinyl silicone resin, specifically by mixing at 40 to 50°C and 400 to 600 rpm for 0.5 to 1.5 h.

[0053] Preferably, in the preparation method of component A, the mixing temperature is 40~50℃, such as 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃ or 50℃.

[0054] Preferably, in the preparation method of component A, the mixing time is 0.5 to 2 h, for example, 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h, 1.5 h, 1.7 h, 1.9 h or 2 h.

[0055] Preferably, in the preparation method of component A, the mixing is carried out under stirring conditions at a speed of 400~600 rpm (e.g., 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm, 500 rpm, 520 rpm, 540 rpm, 560 rpm, 580 rpm or 600 rpm, etc.).

[0056] Preferably, in the preparation method of component B, the mixing temperature is 50~70℃, such as 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, 62℃, 64℃, 66℃, 68℃ or 70℃.

[0057] Preferably, in the preparation method of component B, the mixing time is 2 to 4 hours, such as 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, or 4 hours.

[0058] Preferably, in the preparation method of component B, the mixing is carried out under stirring conditions at a speed of 400~600 rpm (e.g., 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm, 500 rpm, 520 rpm, 540 rpm, 560 rpm, 580 rpm or 600 rpm, etc.).

[0059] Thirdly, the present invention provides a method of using the two-component solvent-free silicone resin insulating varnish as described in the first aspect, the method comprising the following steps:

[0060] (1) Mix component A and component B to obtain an impregnation solution;

[0061] (2) The workpiece is immersed in the impregnation liquid obtained in step (1), and then pretreated, cured and cooled to form an insulating curing film on the surface of the workpiece, thus completing the use of the two-component solvent-free organosilicon resin insulating varnish.

[0062] Step (1) The impregnation solution obtained after mixing components A and B has a room temperature operability time of 4~6 h. After the applicable period, the viscosity of the system will increase significantly and the curing speed will accelerate. Impregnation must be completed within the applicable period. Step (2) The pretreatment process can remove the trace bubbles that may be introduced during the mixing process and allow the resin to initially level. During the main curing process, the hydrogen-containing silicone resin and the vinyl silicone resin undergo a hydrosilylation reaction to form a three-dimensional cross-linked network. After the curing is completed, the heating is stopped and the workpiece is allowed to cool naturally to room temperature. Finally, a uniform (usually 30~50 μm), dense and non-porous insulating curing film is formed on the surface of the workpiece.

[0063] Preferably, the mass ratio of component A to component B in step (1) is 100:(18~25), such as 100:18, 100:19, 100:20, 100:21, 100:22, 100:23, 100:24 or 100:25, etc.

[0064] Preferably, the mixing time in step (1) is 15 to 20 minutes, such as 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0065] Preferably, the mixing in step (1) is carried out at a speed of 300~500 rpm (e.g., 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm or 500 rpm).

[0066] Preferably, the pretreatment temperature in step (2) is 85~95℃, such as 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃ or 95℃.

[0067] Preferably, the pretreatment time in step (2) is 30 to 50 minutes, such as 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes or 50 minutes.

[0068] Preferably, the curing temperature in step (2) is 160~180℃, such as 160℃, 162℃, 164℃, 166℃, 168℃, 170℃, 172℃, 174℃, 176℃, 178℃ or 180℃.

[0069] Preferably, the curing time in step (2) is 3 to 5 hours, such as 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours or 5 hours.

[0070] Fourthly, the present invention provides an application of the two-component solvent-free silicone resin insulating varnish as described in the first aspect in motor coil windings.

[0071] Specifically, the two-component solvent-free silicone resin insulating varnish provided by this invention is suitable for insulation protection of various motor coil windings, such as high-temperature traction motors, new energy vehicle drive motors, special and high-performance motors, or dry-type transformers.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] (1) The two-component solvent-free organosilicon resin insulating varnish provided by the present invention includes component A and component B. Component A includes MQ vinyl silicone resin, other vinyl silicone resins, phenyl-containing silicone resin, toughening agent, coupling agent, catalyst and inhibitor. Component B includes hydrogen-containing silicone resin. By selecting MQ vinyl silicone resin and other vinyl silicone resins for synergistic combination and introducing a combination of synergistic modifiers, the heat resistance, mechanical properties, adhesion and crack resistance of the obtained two-component solvent-free organosilicon resin insulating varnish are effectively improved. After forming the insulating varnish film, it can withstand high temperature of 220℃ for a long time, and has excellent crack resistance and high adhesion. The overall performance is excellent. At the same time, it is solvent-free and environmentally friendly.

[0074] (2) Specifically, by further optimizing and limiting the toughening agent and the phenyl-containing silicone resin, the insulating cured film made from the obtained two-component solvent-free organosilicon resin insulating varnish can have excellent long-term heat resistance and a volume resistivity of 1.3×10⁻⁶. 16 ~3.2×10 16 The electrical strength reaches 22~27 MV / m, and the crack resistance test can withstand at least 18 cycles of hot and cold cycles from -40 to 220℃ without cracking. The adhesion test can reach level 1. Detailed Implementation

[0075] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0076] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0077] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0078] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0079] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0080] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0081] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0082] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0083] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0084] In this invention, "optional" means that something is optional, that is, it refers to any one of the two parallel solutions of "having" or "not having". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0085] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0086] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0087] The following is some information about the raw materials involved in the specific embodiments:

[0088] (1) MQ vinyl silicone resin: viscosity is 6500 mPa·s, vinyl content is 1.3% by mass, purchased from Ningbo Runhe Materials, grade RH-S0826H;

[0089] (2) Other vinyl silicone resins: viscosity of 90 mPa·s, vinyl content of 1.2% by mass, purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd., brand name GP-Vi-100H;

[0090] (3) Phenyl-containing silicone resin A: The phenyl content is 40% by mass, purchased from Hubei Longsheng Sihai New Materials, brand name SH-3048;

[0091] Phenyl silicone resin B: The phenyl content is 26% by mass, purchased from Hubei Longsheng Sihai New Materials, brand name SH-3047;

[0092] The phenyl-containing silicone resin C: The phenyl content is 50% by mass, purchased from Hubei Longsheng Sihai New Materials, brand name SH-3050;

[0093] (4) Polyester modified silicone resin: purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd., brand name SH-022L;

[0094] (5) Polyurethane acrylate modified silicone resin: purchased from Hubei Longsheng Sihai New Materials, brand name SH-024;

[0095] (6) γ-glycidyl etheroxypropyltrimethoxysilane: purchased from Shanghai Testing, brand name KH560;

[0096] (7) Platinum-vinylsiloxane complex: purchased from Shenzhen Taike Technology, grade Pt-5000;

[0097] (8) Hydrogen-containing silicone resin: viscosity of 20 mPa·s, hydrogen mass percentage of 1.5%, purchased from Shandong Dayi Chemical, brand name DY-H202;

[0098] (9) Hindered phenolic antioxidants: specifically Rianlon 1135.

[0099] Examples 1-7 and Comparative Examples 1-5

[0100] Examples 1-7 and Comparative Examples 1-5 each provide a two-component solvent-free silicone resin insulating varnish, all of which contain component A and component B. The specific components of component A and component B are shown in Table 1 and Table 2. In Table 1 and Table 2, the dosage range of each component is "parts by weight".

[0101] Table 1

[0102]

[0103] Table 2

[0104]

[0105] The preparation methods of the two-component solvent-free silicone resin insulating varnishes provided in Examples 1-7 and Comparative Examples 1-5 include the preparation of component A and component B:

[0106] The preparation method of component A includes: first, stirring the catalyst, inhibitor and 10-20 times the amount of other vinyl silicone resins at 405°C and 500 rpm for 1 h to obtain a premix; then, stirring the obtained premix, MQ vinyl silicone resin, other vinyl silicone resins, phenyl-containing silicone resin, toughening agent, coupling agent and antioxidant in a vacuum stirrer at 60°C and 500 rpm for 3 h to ensure that each component is fully dispersed to obtain component A.

[0107] The preparation method of component B includes: mixing hydrogen-containing silicone resin and antioxidant in a vacuum stirrer at 55°C and 500 rpm for 3 h to obtain component B.

[0108] Performance testing:

[0109] First, the two-component solvent-free silicone resin insulating varnishes provided in Examples 1-7 and Comparative Examples 1-5 were respectively prepared into insulating curing films. The preparation method of the insulating curing film includes the following steps:

[0110] (1) Weigh component A and component B at a mass ratio of 100:20, slowly pour component B into component A, mix at room temperature at a speed of 400 rpm for 20 min, degas under vacuum during stirring, observe the state of the material, ensure no stratification or bubbles, and obtain the impregnation liquid.

[0111] (2) The copper sheet workpiece is immersed in the impregnation solution obtained in step (1). The immersed workpiece is placed in an oven and kept at 90°C for 40 min to remove any trace bubbles that may be introduced during the mixing process, while allowing the resin to flow initially. Then the temperature is raised to 170°C and kept at 4 h to complete the curing. After curing, the oven is closed and the copper sheet workpiece is allowed to cool naturally to room temperature with the oven (to avoid excessive internal stress in the film due to rapid cooling). Finally, a uniform (40 μm) dense and non-porous insulating cured film is formed.

[0112] Then, the insulating cured film was tested as follows:

[0113] (1) Long-term heat resistance: After aging at 220℃ for 1000 h, the volume resistivity was tested according to GB / T 31838.2-2019 and the electrical strength was tested according to GB / T 1408.1-2016;

[0114] (2) Crack resistance: After being subjected to a hot and cold cycle of -40~220℃, the number of cycles in which cracking occurs was observed;

[0115] (3) Adhesion: Cross-cut test, referring to GB / T 9286-2021.

[0116] The insulating cured films prepared from the two-component solvent-free silicone resin insulating varnishes provided in Examples 1-7 and Comparative Examples 1-5 were tested according to the above test methods. The test results are shown in Table 3.

[0117] Table 3

[0118]

[0119] According to the data in Table 3:

[0120] The insulating cured films made from the two-component solvent-free silicone resin insulating varnishes provided in Examples 1-3 exhibit excellent long-term heat resistance and a volume resistivity of 1.3 × 10⁻⁶. 16 ~3.2×10 16 Ω·cm, electrical strength of 22~27 MV / m, crack resistance test can withstand 18 cycles of hot and cold cycles from -40 to 220℃ without cracking, and adhesion test can reach level 1.

[0121] Compared with Example 1, Examples 4 and 5 only used polyester-modified silicone resin or polyurethane acrylate-modified silicone resin as toughening agents, resulting in poor crack resistance of the obtained insulating cured film and reduced long-term heat resistance.

[0122] Compared with Example 1, the two-component solvent-free silicone resin insulating varnishes provided in Examples 6 and 7 have lower and higher phenyl content in the added phenyl-containing silicone resin, respectively. This also results in poor crack resistance of the obtained insulating cured film and reduced long-term heat resistance. Furthermore, the higher phenyl content in the added phenyl-containing silicone resin also leads to reduced adhesion of the obtained insulating cured film.

[0123] Compared with Example 1, the amount of MQ vinyl silicone resin added in the two-component solvent-free silicone resin insulating varnish provided in Comparative Examples 1 and 2 was too low and too high, respectively, resulting in poor long-term heat resistance, crack resistance and adhesion of the obtained insulating cured film.

[0124] Compared with Example 1, the two-component solvent-free silicone resin insulating varnish provided in Comparative Example 3 did not contain phenyl silicone resin, which also resulted in poor long-term heat resistance, crack resistance and adhesion of the resulting insulating cured film.

[0125] Compared with Example 1, the two-component solvent-free silicone resin insulating varnish provided in Comparative Example 4 did not contain a toughening agent, resulting in poor crack resistance and low adhesion of the resulting insulating cured film.

[0126] Compared with Example 1, the two-component solvent-free silicone resin insulating varnish provided in Comparative Example 5 did not contain a coupling agent, resulting in very low adhesion of the resulting insulating cured film, only level 4.

[0127] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A two-component solventless silicone resin insulating paint, characterized by, The two-component solvent-free type silicone resin insulating paint comprises an A component and a B component; The A component comprises the following components by weight: MQ vinyl silicone resin 15-35 wt.%; Other vinyl silicone resin 20-42 wt.%; Phenyl-containing silicone resin 8-15 wt.%; Toughening agent 3-16 wt.%; Coupling agent 1-3 wt.%; Catalyst 0.02-0.08 wt.%; Inhibitor 0.004-0.08 wt.%; The B component comprises the following components by weight: Hydrogen-containing silicone resin 85-97 wt.%.

2. The two-component solventless silicone resin insulating paint according to claim 1, characterized by, The viscosity of the MQ vinyl silicone resin is 5000-12000 mPa·s; Preferably, the mass percentage content of vinyl in the MQ vinyl silicone resin is 1.5-2%; Preferably, the viscosity of the other vinyl silicone resin is 10-150 mPa·s; Preferably, the mass percentage content of vinyl in the other vinyl silicone resin is 1-1.5%.

3. The two-component solventless silicone resin insulating paint according to claim 1 or 2, characterized by, The mass percentage content of phenyl in the phenyl-containing silicone resin is 35-45%.

4. The two-component solventless silicone resin insulating paint according to any one of claims 1 to 3, characterized by, The toughening agent comprises a compound of polyester-modified silicone resin and polyurethane acrylate-modified silicone resin; Preferably, the mass ratio of the polyester-modified silicone resin to the polyurethane acrylate-modified silicone resin is 1:(0.5-2); Preferably, the coupling agent comprises γ-glycidoxypropyltrimethoxysilane; Preferably, the catalyst comprises platinum-gold catalyst, and further preferably platinum-vinyl siloxane complex; Preferably, the inhibitor comprises alkyne alcohol compound; Preferably, the alkyne alcohol compound comprises 1-ethynyl-1-cyclohexanol and / or 2-methyl-3-butyn-2-ol.

5. The two-component solventless silicone resin insulating paint according to any one of claims 1 to 4, characterized by, The viscosity of the hydrogen-containing silicone resin is 18-60 mPa·s; Preferably, the mass percentage content of hydrogen in the hydrogen-containing silicone resin is 1-1.5%; Preferably, the B component further comprises antioxidant; Preferably, the content of antioxidant in the B component is 0.2-1 wt.%; Preferably, the antioxidant comprises hindered phenol antioxidant.

6. A method for producing a two-component solventless silicone resin insulating paint according to any one of claims 1 to 5, characterized by, The preparation method comprises preparation of the A component and preparation of the B component; The preparation method of the A component comprises mixing the MQ vinyl silicone resin, the other vinyl silicone resin, the phenyl-containing silicone resin, the toughening agent, the coupling agent, the catalyst and the inhibitor to obtain the A component; The preparation method of the B component comprises mixing the hydrogen-containing silicone resin and optionally antioxidant to obtain the B component.

7. The production method according to claim 6, wherein The catalyst and the inhibitor are mixed in the form of premix liquid; Preferably, in the preparation method of the A component, the temperature of the mixing is 40-50℃, and the time is 0.5-2 h; Preferably, in the preparation method of the A component, the mixing is carried out under stirring condition at a rotation speed of 400-600 rpm; Preferably, in the preparation method of the B component, the temperature of the mixing is 50-70℃, and the time is 2-4 h; Preferably, in the preparation method of the B component, the mixing is carried out under stirring condition at a rotation speed of 400-600 rpm.

8. A method of using the two-component solventless silicone resin insulating paint according to any one of claims 1 to 5, characterized by, The use method comprises the following steps: (1) mixing the A component and the B component to obtain impregnating liquid; (2) immersing the workpiece in the impregnating solution obtained in step (1), and then pre-treating, curing and cooling to form an insulating cured film on the surface of the workpiece, thereby completing the use of the two-component solvent-free organic silicon resin insulating paint.

9. The method of use of claim 8, wherein, The mass ratio of the A component and the B component in step (1) is 100:(18-25); Preferably, the mixing time in step (1) is 15-20 min. Preferably, the mixing in step (1) is carried out at a rotation speed of 300-500 rpm. Preferably, the pre-treatment temperature in step (2) is 85-95℃, and the time is 30-50 min. Preferably, the curing temperature in step (2) is 160-180℃, and the time is 3-5 h.

10. The use of the two-component solvent-free organic silicon resin insulating paint according to any one of claims 1-5 in a motor coil winding.

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