Bi-component epoxy pouring sealant as well as preparation method and application thereof

Abstract

The invention discloses a two-component epoxy pouring sealant as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The bi-component epoxy pouring sealant comprises a component A and a component B. The component A comprises the following raw materials: 60-100 parts of modified epoxy resin; 5-25 parts of a reactive diluent; 1 to 10 parts of nano silicon dioxide; the component B comprises the following raw materials in parts by mass: 50-60 parts of an alicyclic amine curing agent; 20-30 parts of a polyether amine curing agent; 10 to 15 parts of methyl tetrahydrophthalic anhydride; 3-5 parts of a silane modifier; 0.1 to 0.5 part of a defoaming agent; the modified epoxy resin is prepared by carrying out esterification reaction on bisphenol A type epoxy resin and long-chain fatty acid for modification and then carrying out graft modification with polypropylene glycol diglycidyl ether. In addition, the invention also provides a preparation method of the two-component epoxy pouring sealant. The epoxy pouring sealant provided by the invention has excellent bonding performance on non-polar plastics such as PP / PE and the like.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a two-component epoxy potting compound, its preparation method, and its application. Background Technology

[0002] Epoxy resin is a general term for chemical compounds whose molecular structure contains two or more epoxy groups, which, in the presence of a curing agent, can form a three-dimensional network of cured products. The unique epoxy, hydroxyl, and ether bonds in the epoxy resin molecule give it excellent dielectric, mechanical, adhesive, and corrosion resistance properties. Furthermore, it has low shrinkage and linear expansion coefficients after curing, resulting in dimensional stability of the cured product, good processability, and excellent overall performance. Due to the flexibility and diversity of epoxy resin formulation design, it can adapt to almost any performance requirement and can be processed into coatings, composite materials, and adhesives. It is widely used in anti-corrosion coatings, electrical insulation, wind turbine blades, new energy vehicles, photovoltaic power generation, military industry, aerospace, and many other fields. Therefore, epoxy resin has become one of the three major general-purpose thermosetting resins.

[0003] Epoxy potting compounds are used in aerospace electronics, transformers, sensors, power modules, and new energy vehicle electronics, providing protection such as insulation, moisture resistance, shock absorption, and thermal conductivity. However, traditional epoxy potting compounds have poor adhesion to non-polar plastics (such as PP / PE) (their tensile shear strength is typically less than 1 MPa). Adding tackifiers may not only affect the transparency of the epoxy potting compound (light transmittance decreases by more than 15%), but also its storage stability. Furthermore, the high curing shrinkage stress of ordinary epoxy potting compounds can lead to delamination at the plastic interface. Therefore, to improve the adhesion between epoxy and PP / PE, pretreatment of the bonding substrate is necessary, such as applying a primer, surface ionization treatment, or plasma treatment, to enhance epoxy adhesion. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a two-component epoxy potting compound, its preparation method and application, thereby solving the technical problem of poor adhesion performance of epoxy potting compounds to non-polar plastics such as PP / PE in the prior art.

[0005] To achieve the above technical objectives, the present invention provides a two-component epoxy potting compound, comprising component A and component B. The raw materials of component A, calculated by mass parts, include: 60-100 parts of modified epoxy resin; 5-25 parts of reactive diluent; and 1-10 parts of nano-silica.

[0006] The raw materials of component B, calculated by mass parts, include: 50-60 parts of alicyclic amine curing agent; 20-30 parts of polyether amine curing agent; 10-15 parts of methyltetrahydrophthalic anhydride; 3-5 parts of silane modifier; and 0.1-0.5 parts of defoamer.

[0007] The modified epoxy resin is prepared by esterification of bisphenol A type epoxy resin with long-chain fatty acids, followed by graft modification with polypropylene glycol diglycidyl ether; the silane modifier is a mixture of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent.

[0008] In any embodiment, the active diluent is one or more of neopentyl glycol diglycidyl ether, carbododecyl glycidyl ether, and castor oil triglycidyl ether; and / or, the nano silica is nano silica that has undergone surface hydrophobic treatment, and the particle size of the nano silica is 20-40 nm.

[0009] In any embodiment, the alicyclic amine curing agent is one or more of isophorone diamine, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, and 4,4'-diaminodicyclohexylmethane.

[0010] In any embodiment, the defoamer is a silicone-modified polyacrylate defoamer.

[0011] In any embodiment, the long-chain fatty acid is one or more of C12 to C18 long-chain fatty acids.

[0012] In any embodiment, the number-average molecular weight Mn of the polypropylene glycol diglycidyl ether is 400–600 g / mol.

[0013] In any embodiment, the mass ratio of component A to component B is 100:(30-50).

[0014] Furthermore, this invention also proposes a method for preparing the above-mentioned two-component epoxy potting compound, comprising the following steps:

[0015] Preparation of component A:

[0016] S1. Bisphenol A type epoxy resin, long-chain fatty acid and triphenylphosphine catalyst are mixed and then heated under an inert gas atmosphere to obtain partially esterified modified epoxy resin.

[0017] S2. Mix the partially esterified modified epoxy resin obtained in step S1 with polypropylene glycol diglycidyl ether, and heat and react under an inert gas atmosphere to obtain modified epoxy resin.

[0018] S3. The modified epoxy resin, reactive diluent and nano silica are stirred and mixed, and after degassing, component A is obtained;

[0019] Preparation of component B:

[0020] The alicyclic amine curing agent, polyether amine curing agent, methyltetrahydrophthalic anhydride, silane modifier and defoamer are stirred and mixed, and defoaming is performed to obtain component B of transparent two-component epoxy potting compound;

[0021] The two-component epoxy potting compound is prepared by mixing component A and component B.

[0022] In any embodiment, in step S1, the molar ratio of the epoxy group of the bisphenol A type epoxy resin to the carboxyl group of the long-chain fatty acid is 1:(0.15-0.25); and / or, the amount of the triphenylphosphine catalyst added is 0.3-0.5 wt% of the total mass of the bisphenol A type epoxy resin and the long-chain fatty acid; and / or, the heating reaction temperature is 120°C-150°C, and the reaction time is 3-5 hours.

[0023] In any embodiment, in step S2, the mass ratio of the partially esterified modified epoxy resin to the polypropylene glycol diglycidyl ether is 100:(10-20); and / or, in step S2, the heating reaction temperature is 70℃-90℃, and the reaction time is 1-3 hours; and / or, in step S3, the stirring speed is 2000rpm-3000rpm, and the stirring time is 5-6 hours; and / or, in the preparation of component B, the stirring speed is 500rpm-1000rpm, and the stirring time is 1-3 hours.

[0024] The present invention also proposes the application of the above-mentioned two-component epoxy potting compound or the two-component epoxy potting compound prepared by the above-mentioned method in the encapsulation of electronic and electrical components.

[0025] Compared with the prior art, the beneficial effects of the present invention include: the modified epoxy resin proposed in this invention uses long-chain fatty acids to esterify some of the hydroxyl groups of the epoxy resin backbone, and the long-chain fatty acids can form molecular chain entanglement with plastics, enhancing the adhesion between the modified epoxy resin and the plastic substrate. The long fatty acid chains can enhance compatibility with non-polar plastics. In addition, silanes can form Si-OC chemical bonds at the interface, further improving the bonding strength and moisture resistance between the modified resin and the plastic. The low molecular weight polypropylene glycol diglycidyl ether flexible segments can reduce the modulus of the epoxy potting compound (from 1.8 GPa to 1.2 GPa). In other words, the flexible segments can reduce the curing shrinkage stress of the resin. Under the combined action of other components, the epoxy potting compound exhibits excellent adhesion performance to non-polar plastics such as PP / PE. Detailed Implementation

[0026] The "range" disclosed in this application is defined by 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 a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, 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 a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, 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 stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0028] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0029] This specific embodiment provides a two-component epoxy potting compound, including component A and component B. The raw materials of component A, calculated by mass parts, include: 60-100 parts of modified epoxy resin; 5-25 parts of reactive diluent; and 1-10 parts of nano-silica.

[0030] The raw materials of component B, calculated by mass parts, include: 50-60 parts of alicyclic amine curing agent; 20-30 parts of polyether amine curing agent; 10-15 parts of methyltetrahydrophthalic anhydride; 3-5 parts of silane modifier; and 0.1-0.5 parts of defoamer.

[0031] The modified epoxy resin is prepared by esterification of bisphenol A type epoxy resin with long-chain fatty acids, followed by graft modification with polypropylene glycol diglycidyl ether; the silane modifier is a mixture of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent.

[0032] In some embodiments, the reactive diluent is one or more of neopentyl glycol diglycidyl ether, carbododecyl glycidyl ether, and castor oil triglycidyl ether; the nano-silica is nano-silica with a surface hydrophobic treatment and a particle size of 20-40 nm; the alicyclic amine curing agent is one or more of isophorone diamine, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, and 4,4'-diaminodicyclohexylmethane; the defoamer is an organosilicon-modified polyacrylate defoamer; the long-chain fatty acid is one or more of C12-C18 long-chain fatty acids; the number-average molecular weight (Mn) of the polypropylene glycol diglycidyl ether is 400-600 g / mol; and the mass ratio of component A to component B is 100:(30-50). Nano-SiO2 reinforcement and toughening technology: Nano-SiO2 with a size of 20-40nm not only does not affect the transparency of epoxy potting compound, but also limits the shrinkage of epoxy potting compound (CTE decreases from 65 to 48ppm / ℃), thereby reducing the shrinkage stress of resin curing.

[0033] In some embodiments, the surface-hydrophobic nano-silica is prepared by the following steps: 1. First, add dehydrated nano-silica (e.g., 20g) and anhydrous ethanol (200ml) to a three-necked flask, stir to form a suspension, then add about (0.5-1ml) acetic acid, adjust the pH of the system to a weakly acidic level of 4-5, and set aside.

[0034] 2. After adding 15-30% of the mass of silica-containing silane coupling agent to the system (the addition should be completed within 30 minutes), react at 70-80℃ for 4-8 hours (reflux).

[0035] 3. Cool to room temperature, centrifuge, and wash with anhydrous ethanol 3-5 times to remove unreacted silanes and byproducts;

[0036] 4. Vacuum drying at 60-80℃ for 24 hours yields hydrophobic nano-treated silica.

[0037] This specific embodiment also proposes a method for preparing the above-mentioned two-component epoxy potting compound, including the following steps:

[0038] Preparation of component A:

[0039] S1. Bisphenol A type epoxy resin, long-chain fatty acid and triphenylphosphine catalyst are mixed and then heated under an inert gas atmosphere to obtain partially esterified modified epoxy resin.

[0040] S2. Mix the partially esterified modified epoxy resin obtained in step S1 with polypropylene glycol diglycidyl ether, and heat and react under an inert gas atmosphere to obtain modified epoxy resin.

[0041] S3. The modified epoxy resin, reactive diluent and nano silica are stirred and mixed, and after degassing, component A is obtained;

[0042] Preparation of component B:

[0043] The alicyclic amine curing agent, polyether amine curing agent, methyltetrahydrophthalic anhydride, silane modifier and defoamer are stirred and mixed, and defoaming is performed to obtain component B of transparent two-component epoxy potting compound;

[0044] The two-component epoxy potting compound is prepared by mixing component A and component B.

[0045] In some embodiments, in step S1, the molar ratio of the epoxy group of the bisphenol A type epoxy resin to the carboxyl group of the long-chain fatty acid is 1:(0.15-0.25); the amount of the triphenylphosphine catalyst added is 0.3-0.5 wt% of the total mass of the bisphenol A type epoxy resin and the long-chain fatty acid; the heating reaction temperature is 120°C-150°C, and the reaction time is 3-5 hours.

[0046] In some embodiments, in step S2, the mass ratio of the partially esterified modified epoxy resin to the polypropylene glycol diglycidyl ether is 100:(10-20); in step S2, the heating reaction temperature is 70℃-90℃, and the reaction time is 1-3 hours; in step S3, the stirring speed is 2000rpm-3000rpm, and the stirring time is 5-6 hours; in the preparation of component B, the stirring speed is 500rpm-1000rpm, and the stirring time is 1-3 hours.

[0047] This specific embodiment also proposes the application of the above-mentioned two-component epoxy potting compound or the two-component epoxy potting compound prepared by the above-mentioned method in the encapsulation of electronic and electrical components.

[0048] The transparent two-component epoxy potting compound of the present invention can be used in the encapsulation of electronic and electrical components, and is particularly suitable for the potting of plastic shells of electronic modules in new energy vehicles and a wide range of other fields. It is especially suitable for potting and bonding with low polarity plastic substrates such as PP / PE, such as new energy vehicle motor controllers, on-board chargers, aerospace electronic equipment, high-temperature industrial sensors, and high-power power module potting and protection.

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0051] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in a different order than that described herein.

[0052] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0053] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0054] The nano-silica with hydrophobic surface treatment in the following examples was prepared by the following steps:

[0055] 1. First, add 20g of dehydrated nano-silica and 200ml of anhydrous ethanol to a three-necked flask. After stirring to form a suspension, add about 0.8mL of acetic acid to adjust the pH of the system to a weakly acidic level of 4-5. Set aside for later use.

[0056] 2. After adding 20% ​​of the mass of silica-containing silane coupling agent to the system (the addition should be completed within 30 minutes), react at 75°C for 6 hours (reflux).

[0057] 3. Cool to room temperature, centrifuge, and wash with anhydrous ethanol 3-5 times to remove unreacted silanes and byproducts;

[0058] 4. Vacuum drying at 70℃ for 24 hours yields hydrophobic nano-treated silica.

[0059] Example 1

[0060] This embodiment proposes a transparent two-component epoxy potting compound with excellent plastic adhesion, comprising component A and component B in a mass ratio of 100:10. Component A consists of: 60 parts modified epoxy resin; 5 parts neopentyl glycol diglycidyl ether; and 1 part nano-silica with a diameter of 20 nm. Component B consists of: 50 parts isophorone diamine (IPDA); 20 parts polyetheramine D230; 10 parts methyltetrahydrophthalic anhydride; 3 parts silane modifier; and 0.1 parts defoamer.

[0061] The transparent two-component epoxy potting compound with excellent plastic adhesion in this embodiment is prepared by the following steps:

[0062] (1) Bisphenol A type epoxy resin E51 and lauric acid were added to a reaction vessel, with an epoxy group to carboxyl group molar ratio of 1:0.15. After adding 0.3 wt% of triphenylphosphine catalyst, the mixture was heated to 120°C under nitrogen protection and reacted for 3 hours to obtain a partially esterified epoxy resin. The partially esterified lauric acid E51 epoxy resin and polypropylene glycol diglycidyl ether (Mn of 400 g / mol) were mixed, with a mass ratio of 100:10. The mixture was heated to 70°C under nitrogen protection and reacted for 1 hour to obtain the modified epoxy resin in this example.

[0063] (2) Mix 60 parts of the modified epoxy resin prepared in step (1), 5 parts of neopentyl glycol diglycidyl ether and 1 part of nano silica with a particle size of 20 nm under high speed stirring at 2000 rpm for 5 h, and then vacuum degassing to obtain component A of transparent two-component epoxy potting compound.

[0064] (3) Add 50 parts of isophorone diamine (IPDA), 20 parts of polyetheramine D230, 10 parts of methyltetrahydrophthalic anhydride, 3 parts of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent in a mass ratio of 3:1 and 0.1 parts of organosilicon modified polyacrylate defoamer to a reactor and mix at 500 rpm for 1 h. Vacuum degassing is then performed to obtain component B of transparent two-component epoxy potting compound.

[0065] (4) Accurately weigh 100g of component A prepared in step (2) and 10g of component B prepared in step (3), stir and mix evenly and degas to obtain a transparent two-component epoxy potting compound with excellent plastic adhesion.

[0066] Its performance was tested, and the test results are shown in Table 1.

[0067] Example 2

[0068] This embodiment proposes a transparent two-component epoxy potting compound with excellent plastic adhesion, comprising component A and component B in a mass ratio of 100:50. Component A consists of: 100 parts modified epoxy resin; 25 parts dodecyl glycidyl ether; and 10 parts nano-silica with a particle size of 40 nm. Component B consists of: 60 parts 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC); 30 parts polyetheramine D230; 15 parts methyltetrahydrophthalic anhydride; 5 parts silane modifier; and 0.5 parts defoamer.

[0069] The transparent two-component epoxy potting compound with excellent plastic adhesion in this embodiment is prepared by the following steps:

[0070] (1) Bisphenol A type epoxy resin E51 and myristic acid were added to a reactor with an epoxy group to carboxyl group molar ratio of 1:0.25. After adding 0.5 wt% of triphenylphosphine catalyst, the mixture was heated to 150°C under nitrogen protection and reacted for 5 h to obtain a partially esterified epoxy resin. The myristic acid partially esterified E51 epoxy resin and polypropylene glycol diglycidyl ether (Mn = 600 g / mol) were mixed with a mass ratio of 100:20. The mixture was heated to 90°C under nitrogen protection and reacted for 3 h to obtain the modified epoxy resin in this example.

[0071] (2) 100 parts of the modified epoxy resin prepared in step (1), 25 parts of dodecyl glycidyl ether and 10 parts of nano silica with a particle size of 40 nm were mixed at a high speed of 3000 rpm for 6 h, and then vacuum degassed to obtain component A of transparent two-component epoxy potting compound.

[0072] (3) Add 60 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC), 30 parts of polyetheramine D230, 15 parts of methyltetrahydrophthalic anhydride, 5 parts of a mixture of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent in a mass ratio of 3:1 and 0.5 parts of organosilicon-modified polyacrylate defoamer to a reactor and mix at 1000 rpm for 3 h. Vacuum degassing is then performed to obtain component B of transparent two-component epoxy potting compound.

[0073] (4) Accurately weigh 100g of component A prepared in step (2) and 50g of component B prepared in step (3), stir and mix evenly and degas to obtain a transparent two-component epoxy potting compound with excellent plastic adhesion.

[0074] Its performance was tested, and the test results are shown in Table 1.

[0075] Example 3

[0076] This embodiment proposes a transparent two-component epoxy potting compound with excellent plastic adhesion, comprising component A and component B in a mass ratio of 100:40. Component A consists of: 80 parts modified epoxy resin; 15 parts castor oil triglycidyl ether; and 5 parts nano-silica with a particle size of 30 nm. Component B consists of: 55 parts 1,3-cyclohexanedimethylamine (1,3-BAC); 25 parts polyetheramine D230; 20 parts methyltetrahydrophthalic anhydride; 4 parts silane modifier; and 0.3 parts defoamer.

[0077] The transparent two-component epoxy potting compound with excellent plastic adhesion in this embodiment is prepared by the following steps:

[0078] (1) Bisphenol A type epoxy resin E51 and palmitic acid were added to a reactor with an epoxy group to carboxyl group molar ratio of 1:0.20. After adding 0.4 wt% of triphenylphosphine catalyst, the mixture was heated to 135°C under nitrogen protection and reacted for 2 hours to obtain a partially esterified epoxy resin. The palmitic acid partially esterified E51 epoxy resin and polypropylene glycol diglycidyl ether (Mn of 500 g / mol) were mixed at a mass ratio of 100:15. The mixture was heated to 80°C under nitrogen protection and reacted for 2 hours to obtain the modified epoxy resin in this example.

[0079] (2) 80 parts of the prepared modified epoxy resin, 15 parts of castor oil triglycidyl ether and 5 parts of nano silica with a particle size of 30 nm were mixed at a high speed of 2500 rpm for 5 h, and then vacuum degassed to obtain component A of transparent two-component epoxy potting compound.

[0080] (3) Add 55 parts of 1,3-cyclohexanedimethylamine (1,3-BAC), 25 parts of polyetheramine D230, 20 parts of methyltetrahydrophthalic anhydride, 4 parts of a mixture of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent in a mass ratio of 3:1 and 0.3 parts of organosilicon-modified polyacrylate defoamer to a reactor and mix at 800 rpm for 2 h. Vacuum degassing is then performed to obtain component B of the transparent two-component epoxy potting compound.

[0081] (4) Accurately weigh 100g of component A prepared in step (2) and 40g of component B prepared in step (3), stir and mix evenly and degas to obtain a transparent two-component epoxy potting compound with excellent plastic adhesion.

[0082] Its performance was tested, and the test results are shown in Table 1.

[0083] Comparative Example 1

[0084] This comparative example presents a two-component epoxy potting compound, comprising component A and component B, with a mass ratio of component A to component B of 100:10. Component A consists of: 60 parts of bisphenol A type epoxy resin E51; 5 parts of neopentyl glycol diglycidyl ether; and 1 part of nano-silica with a particle size of 20 nm. Component B consists of: 50 parts of isophorone diamine (IPDA); 20 parts of polyetheramine D230; 10 parts of methyltetrahydrophthalic anhydride; 3 parts of silicone coupling agent KH560; and 0.1 parts of defoamer.

[0085] The two-component epoxy potting compound proposed in this comparative example is prepared by the following steps:

[0086] (1) 60 parts of bisphenol A type epoxy resin E5, 5 parts of neopentyl glycol diglycidyl ether and 1 part of nano silica with a diameter of 20 nm were added to the reactor and mixed for 5 h under high speed stirring at 2000 rpm. After vacuum degassing, the A component of the two-component epoxy potting compound was obtained.

[0087] (2) Add 50 parts of isophorone diamine (IPDA), 20 parts of polyetheramine D230, 10 parts of methyltetrahydrophthalic anhydride, 3 parts of silicone coupling agent KH560 and 0.1 parts of organosilicon modified polyacrylate defoamer to the reactor and mix at 500 rpm for 1 h. Vacuum degassing is then performed to obtain component B of the two-component epoxy potting compound.

[0088] (3) Accurately weigh 100g of component A prepared in step (1) and 10g of component B prepared in step (2), stir and mix evenly and degas to obtain the two-component epoxy potting compound of this comparative example.

[0089] Its performance was tested, and the test results are shown in Table 1.

[0090] Comparative Example 2

[0091] This comparative example presents a two-component epoxy potting compound, comprising component A and component B, with a mass ratio of 100:50. Component A consists of: 100 parts of bisphenol A type epoxy resin E51; 25 parts of dodecyl glycidyl ether; and 10 parts of 40 nm diameter nano-silica. Component B consists of: 60 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC); 30 parts of polyetheramine D230; 15 parts of methyltetrahydrophthalic anhydride; 5 parts of silicone coupling agent KH560; and 0.5 parts of defoamer.

[0092] The two-component epoxy potting compound proposed in this comparative example is prepared by the following steps:

[0093] (1) 100 parts of bisphenol A type epoxy resin E51, 25 parts of dodecyl glycidyl ether and 10 parts of nano silica with a particle size of 40 nm were added to the reactor and mixed for 6 h under high speed stirring at 3000 rpm. After vacuum degassing, transparent two-component epoxy potting compound A component was obtained.

[0094] (2) Add 60 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC), 30 parts of polyetheramine D230, 15 parts of methyltetrahydrophthalic anhydride, 5 parts of silicone coupling agent KH560 and 0.5 parts of organosilicon modified polyacrylate defoamer to a reaction vessel and mix at 1000 rpm for 3 h. Vacuum degassing is then performed to obtain component B of transparent two-component epoxy potting compound.

[0095] (3) Accurately weigh 100g of component A prepared in step (1) and 50g of component B prepared in step (2), stir and mix evenly to obtain the transparent two-component epoxy potting compound of this comparative example.

[0096] Its performance was tested, and the test results are shown in Table 1.

[0097] Comparative Example 3

[0098] This comparative example presents a two-component epoxy potting compound, comprising component A and component B, with a mass ratio of component A to component B of 100:40. Component A consists of: 80 parts of bisphenol A type epoxy resin E51; 15 parts of castor oil triglycidyl ether; and 5 parts of nano-silica with a particle size of 30 nm. Component B consists of: 55 parts of 1,3-cyclohexanedimethylamine (1,3-BAC); 25 parts of polyetheramine D230; 20 parts of methyltetrahydrophthalic anhydride; 4 parts of silicone coupling agent KH560; and 0.3 parts of defoamer.

[0099] The two-component epoxy potting compound proposed in this comparative example is prepared by the following steps:

[0100] (1) Add 80 parts of bisphenol A type epoxy resin E51, 15 parts of castor oil triglycidyl ether and 5 parts of nano silica with a particle size of 30 nm to a reaction vessel and mix for 5 h under high speed stirring at 2500 rpm. After vacuum degassing, the A component of the two-component epoxy potting compound is obtained.

[0101] (2) Add 55 parts of 1,3-cyclohexanedimethylamine (1,3-BAC), 25 parts of polyetheramine D230, 20 parts of methyltetrahydrophthalic anhydride, 4 parts of silicone coupling agent KH560 and 0.3 parts of organosilicon modified polyacrylate defoamer to the reactor and mix at 800 rpm for 2 h. Vacuum degassing is then performed to obtain component B of the two-component epoxy potting compound.

[0102] (3) Accurately weigh 100g of component A prepared in step (1) and 40g of component B prepared in step (2), stir and mix evenly and degas to obtain the two-component epoxy potting compound of this comparative example.

[0103] Its performance was tested, and the test results are shown in Table 1.

[0104] Table 1. Performance test results of epoxy potting compounds obtained from each example and comparative example.

[0105]

[0106] As shown in Table 1, the transparent two-component epoxy potting compounds in Examples 1-3 of this invention all have high light transmittance and long working time. They also have good adhesion to low surface energy plastics such as PP / PE / ABS / PC. They have high use value, good application prospects, and advantages such as simple preparation process and convenient operation. They can be prepared on a large scale and are suitable for industrial production.

[0107] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A two-component epoxy potting compound, characterized in that, It includes component A and component B. The raw materials of component A, calculated by mass parts, include: 60-100 parts of modified epoxy resin; 5-25 parts of reactive diluent; and 1-10 parts of nano-silica. The raw materials of component B, calculated by mass parts, include: 50-60 parts of alicyclic amine curing agent; 20-30 parts of polyether amine curing agent; 10-15 parts of methyltetrahydrophthalic anhydride; 3-5 parts of silane modifier; and 0.1-0.5 parts of defoamer. The modified epoxy resin is prepared by esterification of bisphenol A type epoxy resin with long-chain fatty acids, followed by graft modification with polypropylene glycol diglycidyl ether; the silane modifier is a mixture of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent.

2. The two-component epoxy potting compound according to claim 1, characterized in that, The active diluent is one or more of neopentyl glycol diglycidyl ether, carbododecyl glycidyl ether, and castor oil triglycidyl ether; and / or, the nano silica is nano silica that has undergone surface hydrophobic treatment, and the particle size of the nano silica is 20-40 nm.

3. The two-component epoxy potting compound according to claim 1, characterized in that, The alicyclic amine curing agent is one or more of isophorone diamine, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 1,3-cyclohexanedimethylamine, and 4,4'-diaminodicyclohexylmethane.

4. The two-component epoxy potting compound according to claim 1, characterized in that, The defoamer is an organosilicon-modified polyacrylate defoamer.

5. The two-component epoxy potting compound according to claim 1, characterized in that, The long-chain fatty acid is one or more of C12-C18 long-chain fatty acids.

6. The two-component epoxy potting compound according to claim 1, characterized in that, The number-average molecular weight (Mn) of the polypropylene glycol diglycidyl ether is 400–600 g / mol; and / or, the mass ratio of component A to component B is 100:(30–50).

7. A method for preparing a two-component epoxy potting compound according to any one of claims 1-6, characterized in that, Includes the following steps: Preparation of component A: S1. Bisphenol A type epoxy resin, long-chain fatty acid and triphenylphosphine catalyst are mixed and then heated under an inert gas atmosphere to obtain partially esterified modified epoxy resin. S2. Mix the partially esterified modified epoxy resin obtained in step S1 with polypropylene glycol diglycidyl ether, and heat and react under an inert gas atmosphere to obtain modified epoxy resin. S3. The modified epoxy resin, reactive diluent and nano silica are stirred and mixed, and after degassing, component A is obtained; Preparation of component B: The alicyclic amine curing agent, polyether amine curing agent, methyltetrahydrophthalic anhydride, silane modifier and defoamer are stirred and mixed, and defoaming is performed to obtain component B; The two-component epoxy potting compound is prepared by mixing component A and component B.

8. The method for preparing the two-component epoxy potting compound according to claim 7, characterized in that, In step S1, the molar ratio of epoxy groups to carboxyl groups of the bisphenol A epoxy resin is 1:(0.15-0.25); and / or, the amount of the triphenylphosphine catalyst added is 0.3wt%-0.5wt% of the total mass of the bisphenol A epoxy resin and the long-chain fatty acid; and / or, the heating reaction temperature is 120℃-150℃, and the reaction time is 3-5 hours.

9. The method for preparing the two-component epoxy potting compound according to claim 7, characterized in that, In step S2, the mass ratio of the partially esterified modified epoxy resin to the polypropylene glycol diglycidyl ether is 100:(10-20); and / or, in step S2, the heating reaction temperature is 70℃-90℃, and the reaction time is 1-3 hours; and / or, in step S3, the stirring speed is 2000rpm-3000rpm, and the stirring time is 5-6 hours; and / or, in the preparation of component B, the stirring speed is 500rpm-1000rpm, and the stirring time is 1-3 hours.

10. The two-component epoxy potting compound according to any one of claims 1-7 or the two-component epoxy potting compound prepared by the preparation method according to any one of claims 8-9 is used in the encapsulation of electronic and electrical components.

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