Solvent-free bi-component insulating potting mixture and preparation method thereof

Abstract

The invention discloses a solvent-free bi-component insulating potting mixture and a preparation method thereof, and relates to the technical field of potting compositions. Polyurethane is adopted as a potting composition, the defects that traditional epoxy resin is low in mechanical strength and poor in bonding performance are overcome through the unique structural characteristics of polyurethane, but due to the fact that the heat conductivity coefficient of polyurethane is low, the working stability of an electronic device can be greatly influenced, and the electronic device can be prevented from being damaged. Therefore, the aluminum oxide is used as the modified filler to improve the heat-conducting property of the potting composition, the inorganic filler is used for filling the polymer, the process is simple and easy to control, the processing cost is low, and industrial production is easier to realize.

Description

Technical Field

[0001] The invention relates to the technical field of potting compositions, in particular to a solvent-free two-component insulating potting mixture and a preparation method thereof. Background Art

[0002] With the continuous development of the electronics industry, electronic devices are gradually miniaturized and highly integrated, and the density of devices per unit volume is getting higher and higher. While the performance is improved, the heat generated inside the device is also increasing sharply, becoming one of the important reasons affecting the life of electronic devices. Polyurethane is one of the most widely used polymers. The potting glue based on polyurethane has the advantages of being waterproof, acid-resistant, high and low temperature resistant, and having good insulation. It is widely used in electronic equipment. However, polyurethane materials used as thermal conductive materials have low thermal conductivity, which limits their application in electronic devices. Therefore, it is of great significance to develop polyurethane potting glue with high thermal conductivity;

[0003] CN117551412A discloses a low-cost, high-thermal-conductivity, high-toughness insulating polyurethane potting glue and a preparation method thereof. The low-cost, high-thermal-conductivity, high-toughness insulating polyurethane potting glue comprises component A and component B; the component A comprises the following raw materials in parts by weight: 50-80 parts of castor oil polyether polyol, 20-40 parts of polyester polyol, 200-400 parts of inorganic filler, 1-3 parts of defoamer, 5-10 parts of pigment, 5-18 parts of cross-linking agent, and 0.5-2 parts of catalyst; the component B comprises the following raw materials in parts by weight: 95-100 parts of MDI polyisocyanate; the mass ratio of the component A to the component B is 8:1. Through the adjustment of the formula, the thermal conductivity of the polyurethane potting glue is improved, the heat dissipation performance is excellent, and it has good toughness, resistance to cold and hot shock and insulation, which can meet the customer's requirements for the potting of electronic product components, reduce losses, save energy, and extend service life.

[0004] However, if the inorganic fillers are not modified, they will be unevenly dispersed in the polyurethane, resulting in a decrease in the overall mechanical properties of the final potting composition. Summary of the invention

[0005] The object of the present invention is to provide a solvent-free two-component insulating potting mixture and a preparation method thereof, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A solvent-free two-component insulating potting mixture, comprising component A and component B;

[0008] The component A comprises the following parts by weight: 15 to 25 parts of polypropylene glycol, 8 to 12 parts of castor oil, 0.4 to 0.6 parts of defoamer, 0.2 to 0.4 parts of catalyst and 65 to 75 parts of modified alumina;

[0009] The component B comprises the following parts by weight: 95-98 parts of polymethylene polyphenyl isocyanate, 2-4 parts of molecular sieves and 0.4-0.6 parts of defoaming agent;

[0010] The mass ratio between component A and component B is 4.8-5.2:1.

[0011] As an optimization, the component A includes the following preparation steps: weighing polypropylene glycol, castor oil, defoamer, catalyst and modified alumina according to the above-mentioned mass fractions, mixing the polypropylene glycol and castor oil evenly, vacuum stirring for 2 to 2.5 hours at a temperature of 115 to 125° C., cooling to 25 to 35° C. after stirring, then adding modified alumina, defoamer and catalyst, stirring evenly, obtaining component A, and sealing and storing for standby use.

[0012] As an optimization, the component B includes the following preparation steps: weigh polymethylene polyphenyl isocyanate, molecular sieve and defoamer according to the above-mentioned mass fractions, mix the polymethylene polyphenyl isocyanate, molecular sieve and defoamer evenly at a temperature of 25 to 30° C. to obtain component B, which is sealed and stored for later use.

[0013] As an optimization, the defoamer is a silicone defoamer.

[0014] As an optimization, the catalyst is dibutyltin dilaurate.

[0015] As an optimization, the molecular sieve is type 5A molecular sieve.

[0016] As an optimization, the modified alumina includes the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 8.5 to 9.5 times the mass of deionized water, stirring evenly, then adding alumina powder with a mass of 2 to 2.5 times the mass of deionized water and modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.4 to 0.6 times the mass of deionized water, ultrasonically dispersing for 2 to 2.5 hours at a temperature of 55 to 65° C., filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 3 to 5 times, and then drying for 5 to 6 hours at a temperature of 75 to 85° C. to obtain modified alumina.

[0017] As an optimization, the modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide includes the following preparation steps: adding grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl tris(2-methoxyethoxy)silane to a mixture of 3.5 to 4.5 times the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a mass ratio of 1:1.8 to 2.2. The reaction mixture was stirred evenly in benzene, and then 2.2% to 2.5% of azobisisobutyronitrile by weight of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added. The reaction was carried out under nitrogen protection at a temperature of 35 to 45°C for 18 to 22 hours. After the reaction, petroleum ether was added and allowed to stand for precipitation. The precipitated product was filtered, cleaned and dried to obtain modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0018] As an optimization, the grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide includes the following preparation steps: adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dichloromethane with a mass of 10 to 12 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, stirring evenly, then adding 3-allyl-2-hydroxybenzaldehyde with a mass of 0.85 to 0.95 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically dispersing for 10 to 15 minutes, reacting for 3.5 to 4.5 hours at a temperature of 80 to 90° C. after the ultrasonic dispersion, sealing and standing for stratification after the reaction, removing the lower precipitate and drying in the shade to obtain the grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0019] A method for preparing a solvent-free two-component insulating potting mixture, applied to any one of the solvent-free two-component insulating potting mixtures described above;

[0020] The preparation method of the solvent-free two-component insulating potting mixture comprises the following steps: uniformly mixing component A and component B in proportion, pouring into a polytetrafluoroethylene mold after vacuum degassing treatment, continuing to degas until the surface is flat, curing at a temperature of 25 to 35° C. for 22 to 24 hours and then demoulding to obtain a solvent-free two-component insulating potting mixture.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] The present application uses polyurethane as a potting composition, and overcomes the disadvantages of low mechanical strength and poor bonding performance of traditional epoxy resins through the unique structural characteristics of polyurethane. However, due to the low thermal conductivity of polyurethane itself, it will have a great impact on the working stability of electronic devices. Therefore, the present application uses alumina as a modified filler to improve the thermal conductivity of the potting composition. The inorganic filler is filled with the polymer. The process is simple and easy to control, and the processing cost is low, which makes it easier to achieve industrial production.

[0023] Although a large number of tests have shown that alumina can effectively enhance the thermal conductivity of polyurethane materials, alumina, as an inorganic phase, has poor interfacial compatibility with the organic phase, and there is a difference in the surface tension between alumina powder and polyurethane, which makes it difficult for alumina particles to be evenly dispersed in the organic matrix. Therefore, it is necessary to modify the surface of alumina in order to improve the interfacial affinity between the powder and the polyurethane resin, improve the dispersibility and filling uniformity of the filler, and thus obtain a composite material with excellent performance. Therefore, the present application adopts DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and 3-allyl-2-hydroxybenzaldehyde for grafting. After grafting, it contains hydroxyl groups and double bonds at the same time, and then the silane coupling agent is linked by double bond polymerization, and then the surface of alumina is modified to make the surface of alumina grafted with DOPO, which not only improves the dispersibility and compatibility of alumina, but also improves the heat resistance of polyurethane, and forms a polymerization network with the modified alumina as the center point during the polymerization of polyurethane, thereby improving the mechanical properties of the final potting composition. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] S1, grafting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dichloromethane with a mass of 10 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, stirring evenly, then adding 3-allyl-2-hydroxybenzaldehyde with a mass of 0.85 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically dispersing for 10 minutes, reacting for 3.5 hours at a temperature of 80° C. after the ultrasonic dispersion is completed, sealing and standing for stratification after the reaction is completed, removing the lower precipitate and drying in the shade to obtain grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0027] S2, modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl tris(2-methoxyethoxy)silane to toluene 3.5 times the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a mass ratio of 1:1.8, stirring evenly, then adding azobisisobutyronitrile 2.2% of the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, reacting for 18 hours under nitrogen protection at a temperature of 35°C, adding petroleum ether after the reaction is completed, and then filtering, cleaning and drying the precipitated product to obtain modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0028] S3, the modified alumina comprises the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 8.5 times the mass of the deionized water, stirring evenly, then adding alumina powder with a mass of 2 to 2.5 times the mass of the deionized water and modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.4 times the mass of the deionized water, ultrasonically dispersing for 2 hours at a temperature of 55°C, filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 3 times, and then drying for 5 hours at a temperature of 75°C to obtain modified alumina;

[0029] S4, component A comprises the following preparation steps: weighing polypropylene glycol, castor oil, defoamer, catalyst and modified alumina according to the above mass fractions, mixing the polypropylene glycol and castor oil evenly, vacuuming and stirring for 2 hours at a temperature of 115° C., cooling to 25° C. after stirring, then adding modified alumina, defoamer and catalyst, stirring evenly, obtaining component A, and sealing and storing for standby use;

[0030] S5, component B The component comprises the following preparation steps: weighing polymethylene polyphenyl isocyanate, molecular sieve and defoamer according to the above mass fractions, mixing the polymethylene polyphenyl isocyanate, molecular sieve and defoamer at a temperature of 25°C to obtain component B, and sealing and storing for later use;

[0031] S6. Mix component A and component B evenly in proportion, vacuum degassing treatment and pour into a polytetrafluoroethylene mold, continue degassing until the surface is flat, and demold after curing at a temperature of 25°C for 22 hours to obtain a solvent-free two-component insulating potting mixture; component A contains the following parts by weight: 15 parts of polypropylene glycol, 8 parts of castor oil, 0.4 parts of defoaming agent, 0.2 parts of catalyst and 65 parts of modified alumina; component B contains the following parts by weight: 95 parts of polymethylene polyphenyl isocyanate, 2 parts of molecular sieves and 0.4 parts of defoaming agent; the mass ratio between component A and component B is 4.8:1; the defoaming agent is a silicone defoaming agent, the catalyst is dibutyltin dilaurate, and the molecular sieve is a 5A molecular sieve.

[0032] Example 2

[0033] S1, grafting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dichloromethane with a mass of 11 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, stirring evenly, adding 3-allyl-2-hydroxybenzaldehyde with a mass of 0.9 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically dispersing for 12 minutes, reacting for 4 hours at a temperature of 85° C. after the ultrasonic dispersion is completed, sealing and standing for stratification after the reaction is completed, removing the lower precipitate and drying in the shade to obtain grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0034] S2, modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl tris(2-methoxyethoxy)silane to toluene 4 times the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a mass ratio of 1:2, stirring evenly, then adding azobisisobutyronitrile 2.3% of the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, reacting for 20 hours under nitrogen protection at a temperature of 40°C, adding petroleum ether after the reaction is completed, and then filtering, cleaning and drying the precipitated product to obtain modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0035] S3, modified alumina includes the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 9 times that of deionized water, stirring evenly, then adding alumina powder with a mass of 2.2 times that of deionized water and modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.5 times that of deionized water, ultrasonically dispersing for 2.2 hours at a temperature of 60°C, filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 4 times, and then drying for 5.5 hours at a temperature of 80°C to obtain modified alumina;

[0036] S4, component A comprises the following preparation steps: weighing polypropylene glycol, castor oil, defoamer, catalyst and modified alumina according to the above mass fractions, mixing the polypropylene glycol and castor oil evenly, vacuuming and stirring at a temperature of 120° C. for 2.3 hours, cooling to 30° C. after stirring, then adding modified alumina, defoamer and catalyst, stirring evenly, obtaining component A, and sealing and storing for standby use;

[0037] S5, component B The component comprises the following preparation steps: weighing polymethylene polyphenyl isocyanate, molecular sieve and defoamer according to the above mass fractions, mixing the polymethylene polyphenyl isocyanate, molecular sieve and defoamer at a temperature of 28°C to obtain component B, and sealing and storing for later use;

[0038] S6. Mix component A and component B evenly in proportion, vacuum degassing treatment and pour into a polytetrafluoroethylene mold, continue degassing until the surface is flat, and demold after curing at a temperature of 30°C for 24 hours to obtain a solvent-free two-component insulating potting mixture; component A contains the following parts by weight: 20 parts of polypropylene glycol, 10 parts of castor oil, 0.5 parts of defoaming agent, 0.3 parts of catalyst and 70 parts of modified alumina; component B contains the following parts by weight: 97 parts of polymethylene polyphenyl isocyanate, 3 parts of molecular sieves and 0.5 parts of defoaming agent; the mass ratio between component A and component B is 5:1; the defoaming agent is a silicone defoaming agent, the catalyst is dibutyltin dilaurate, and the molecular sieve is a 5A molecular sieve.

[0039] Example 3

[0040] S1, grafting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dichloromethane with a mass of 12 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, stirring evenly, then adding 3-allyl-2-hydroxybenzaldehyde with a mass of 0.95 times that of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically dispersing for 15 minutes, reacting for 4.5 hours at a temperature of 90° C. after the ultrasonic dispersion is completed, sealing and standing for stratification after the reaction is completed, removing the lower precipitate and drying in the shade to obtain grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0041] S2, modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide includes the following preparation steps: adding grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl tris(2-methoxyethoxy)silane to toluene 4.5 times the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a mass ratio of 1:2.2, stirring evenly, then adding azobisisobutyronitrile 2.5% of the mass of grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, reacting for 22 hours under nitrogen protection at a temperature of 45°C, adding petroleum ether after the reaction is completed, and then filtering, cleaning, and drying the precipitated product to obtain modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0042] S3, the modified alumina comprises the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 9.5 times the mass of the deionized water, stirring evenly, then adding alumina powder with a mass of 2 to 2.5 times the mass of the deionized water and modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.6 times the mass of the deionized water, ultrasonically dispersing for 2.5 hours at a temperature of 65°C, filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 5 times, and then drying for 6 hours at a temperature of 85°C to obtain modified alumina;

[0043] S4, component A comprises the following preparation steps: weighing polypropylene glycol, castor oil, defoamer, catalyst and modified alumina according to the above mass fractions, mixing the polypropylene glycol and castor oil evenly, stirring under vacuum at a temperature of 125° C. for 2.5 hours, cooling to 35° C. after stirring, then adding modified alumina, defoamer and catalyst, stirring evenly, obtaining component A, and sealing and storing for standby use;

[0044] S5, component B The component comprises the following preparation steps: weighing polymethylene polyphenyl isocyanate, molecular sieve and defoamer according to the above mass fractions, mixing the polymethylene polyphenyl isocyanate, molecular sieve and defoamer at a temperature of 30°C to obtain component B, and sealing and storing for later use;

[0045] S6. Mix component A and component B evenly in proportion, vacuum degassing treatment and pour into a polytetrafluoroethylene mold, continue degassing until the surface is flat, and demold after curing at a temperature of 35°C for 24 hours to obtain a solvent-free two-component insulating potting mixture; component A contains the following parts by weight: 25 parts of polypropylene glycol, 12 parts of castor oil, 0.6 parts of defoaming agent, 0.4 parts of catalyst and 75 parts of modified alumina; component B contains the following parts by weight: 98 parts of polymethylene polyphenyl isocyanate, 4 parts of molecular sieves and 0.6 parts of defoaming agent; the mass ratio between component A and component B is 5.2:1; the defoaming agent is a silicone defoaming agent, the catalyst is dibutyltin dilaurate, and the molecular sieve is a 5A molecular sieve.

[0046] Example 4

[0047] The only difference from Example 2 is step S4: Component A includes the following preparation steps: polypropylene glycol, castor oil, defoamer, catalyst and alumina are weighed according to the above mass fractions, polypropylene glycol and castor oil are mixed evenly, vacuumed and stirred for 2.3 hours at a temperature of 120° C., cooled to 30° C. after stirring, and then modified alumina, defoamer and catalyst are added, stirred evenly, to obtain component A, which is sealed and stored for later use;

[0048] Example 5

[0049] The only difference from Example 2 is step S3: the modified alumina includes the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 9 times that of the deionized water, stirring evenly, then adding alumina powder with a mass of 2.2 times that of the deionized water and grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.5 times that of the deionized water, ultrasonically dispersing for 2.2 hours at a temperature of 60°C, filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 4 times, and then drying for 5.5 hours at a temperature of 80°C to obtain modified alumina;

[0050] Example 6

[0051] The only difference from Example 2 is step S3: the modified alumina includes the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 9 times that of the deionized water, stirring evenly, then adding alumina powder with a mass of 2.2 times that of the deionized water and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.5 times that of the deionized water, ultrasonically dispersing for 2.2 hours at a temperature of 60°C, filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 4 times, and then drying for 5.5 hours at a temperature of 80°C to obtain modified alumina;

[0052] Comparative Example 1

[0053] The solvent-free two-component insulating potting mixtures prepared in the above Examples 1 to 6 were tested for mechanical properties, thermal conductivity and flame retardancy;

[0054] Mechanical properties: The tensile strength and elongation at break of the specimens were tested according to GB / T528-2009 standard. The specimens were type I (specimen length was 25 mm) and the tensile rate was 100 mm / min.

[0055] Thermal conductivity: According to GB / T10294-2008 standard, the thermal conductivity tester is used for testing.

[0056] Flame retardant performance: The vertical combustion test of the sample is carried out in accordance with GB / T2408-2021 standard using a horizontal vertical combustion tester;

[0057] Table 1 Experimental data of mechanical properties, thermal conductivity and flame retardancy test

[0058]

[0059]

[0060] From the comparison of experimental data in Table 1, it can be found that Examples 1 to 3 all maintain good performance and are much higher than Examples 4 to 6. It can be expected that they will decrease in Examples 5 and 6, mainly because the lack of pre-grafting makes it impossible for DOPO to link with alumina. In fact, the surface of alumina in the final component A is still unmodified, resulting in its final poor dispersibility. In fact, it can be seen from 4 to 6 in the above table that the tensile strengths in 4 to 6 are basically the same. Although there is a partial gap between the thermal conductivity coefficients, this partial gap is caused by the uneven dispersion therein, which also indirectly verifies that the non-grafting leads to the unmodified surface of the final alumina.

[0061] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A solvent-free two-component insulating potting mixture, characterized in that: Comprising component A and component B; The component A comprises the following parts by weight: 15 to 25 parts of polypropylene glycol, 8 to 12 parts of castor oil, 0.4 to 0.6 parts of defoamer, 0.2 to 0.4 parts of catalyst and 65 to 75 parts of modified alumina; The component B comprises the following parts by weight: 95-98 parts of polymethylene polyphenyl isocyanate, 2-4 parts of molecular sieves and 0.4-0.6 parts of defoaming agent; The mass ratio between component A and component B is 4.8-5.2:

1.

2. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The component A comprises the following preparation steps: weighing polypropylene glycol, castor oil, defoamer, catalyst and modified alumina according to the above-mentioned mass fractions, mixing the polypropylene glycol and castor oil evenly, vacuum stirring for 2 to 2.5 hours at a temperature of 115 to 125° C., cooling to 25 to 35° C. after stirring, then adding modified alumina, defoamer and catalyst, stirring evenly, obtaining component A, and sealing and storing for later use.

3. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The component B comprises the following preparation steps: weighing polymethylene polyphenyl isocyanate, molecular sieve and defoamer according to the above mass fractions, mixing the polymethylene polyphenyl isocyanate, molecular sieve and defoamer evenly at a temperature of 25 to 30° C. to obtain component B, and sealing and storing it for later use.

4. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The defoamer is an organosilicon defoamer.

5. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate.

6. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The molecular sieve is a 5A type molecular sieve.

7. The solvent-free two-component insulating potting mixture according to claim 1, characterized in that: The modified alumina comprises the following preparation steps: adding deionized water to anhydrous ethanol with a mass of 8.5 to 9.5 times the mass of the deionized water, stirring evenly, then adding alumina powder with a mass of 2 to 2.5 times the mass of the deionized water and modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with a mass of 0.4 to 0.6 times the mass of the deionized water, ultrasonically dispersing for 2 to 2.5 hours at a temperature of 55 to 65° C., filtering after ultrasonic dispersion, washing the filtered product with anhydrous ethanol for 3 to 5 times, and then drying for 5 to 6 hours at a temperature of 75 to 85° C. to obtain the modified alumina.

8. The solvent-free two-component insulating potting mixture according to claim 7, characterized in that: The modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl tris(2-methoxyethoxy)silane to toluene with a mass ratio of 1:1.8-2.2, stirring evenly, then adding azobisisobutyronitrile with a mass of 2.2%-2.5% of the mass of the grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, reacting for 18-22 hours under nitrogen protection at a temperature of 35-45°C, adding petroleum ether after the reaction is completed, and precipitating, then filtering, cleaning and drying the precipitated product to obtain the modified 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

9. The solvent-free two-component insulating potting mixture according to claim 8, characterized in that: The grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide comprises the following preparation steps: adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dichloromethane with a mass of 10 to 12 times that of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, stirring evenly, then adding 3-allyl-2-hydroxybenzaldehyde with a mass of 0.85 to 0.95 times that of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ultrasonically dispersing for 10 to 15 minutes, reacting for 3.5 to 4.5 hours at a temperature of 80 to 90° C. after the ultrasonic dispersion is completed, sealing, standing, stratifying, taking out the lower precipitate, and drying in the shade to obtain the grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

10. A method for preparing a solvent-free two-component insulating potting mixture, characterized in that: The solvent-free two-component insulating potting mixture as claimed in any one of claims 1 to 9; The preparation method of the solvent-free two-component insulating potting mixture comprises the following steps: uniformly mixing component A and component B in proportion, pouring into a polytetrafluoroethylene mold after vacuum degassing treatment, continuing to degas until the surface is flat, curing at a temperature of 25 to 35° C. for 22 to 24 hours and then demoulding to obtain a solvent-free two-component insulating potting mixture.

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