Two-component hydrophobic heat-resistant polyurethane potting adhesive and preparation method thereof

Abstract

The present invention belongs to the technical field of polyurethane potting glue, and specifically relates to a two-component hydrophobic heat-resistant polyurethane potting glue and a preparation method thereof. The potting glue is prepared by reacting component A and component B; component A is composed of the following raw materials in parts by weight: modified polyether polyol I: 17-33 parts; modified polyether polyol II: 15-27 parts; diisocyanate: 18-30 parts; plasticizer: 20-34 parts; component B is composed of the following raw materials in parts by weight: polyether polyol III: 47-64 parts; filler: 36-53 parts; catalyst: 0.15-0.35 parts. Siloxane-modified polyether polyol is prepared by introducing siloxane silicon chain segments into the polyether polyol structure through acrylic acid bridging; by introducing more side ethyl, phenyl, and neopentyl structures into the polyether polyol, the intrinsic hydrophobic temperature resistance of the raw material is further improved, so that the polyurethane potting glue exhibits strong hydrophobicity and heat resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane potting adhesives, and in particular relates to a two-component hydrophobic heat-resistant polyurethane potting adhesive and a preparation method thereof. Background Art

[0002] Polyurethane potting glue, also known as PU potting glue, is characterized by low hardness, moderate strength, water resistance, mildew resistance, transparency, excellent electrical insulation and good repairability, non-corrosive to electrical components, and good adhesion to metals such as steel, aluminum, copper, tin, as well as rubber, plastic, wood and other materials. Currently, the most commonly used ones are epoxy resin potting glue, silicone resin potting glue and polyurethane potting glue. Thermal conductive materials need to have high thermal conductivity and stability to ensure the normal operation of materials in high temperature environments: in the field of consumer electronics, thermal conductive materials need to have good thermal conductivity, heat resistance, super hydrophobicity and chemical stability to ensure the normal operation of equipment and stability in underwater environments; in the automotive field, thermal conductive materials need to have high thermal conductivity, mechanical strength and corrosion resistance to cope with complex working conditions. However, a single thermal conductive material often cannot meet complex application requirements. Developing and exploring a new thermal conductive composite material that maintains high thermal conductivity while taking into account other comprehensive application requirements and material properties is the development trend of future applications of thermal conductive materials. In addition, the traditional curing method of thermal conductive packaging materials is mainly high-temperature curing, which can damage products such as chips and electronic devices and shorten their service life.

[0003] Patent CN116376502A discloses a silicone resin modified polyurethane potting adhesive and a preparation method thereof, which uses thermally conductive fillers and silicone resins to improve the thermal conductivity of the material, but its stability is poor and there is a risk of thermal conductive powder precipitation. Patent CN118496807A discloses a single-component high-temperature resistant and water-repellent polyurethane potting adhesive and a preparation method thereof, which introduces benzene rings, fluorine-containing groups, etc. into the molecular structure to improve the temperature resistance of the material, but the fluorine element in the raw material may be released into the environment during use, causing environmental pollution. Patent CN110105718A discloses a new energy vehicle battery potting material and a preparation method thereof, which improves the low-temperature-high-temperature impact performance of the material through the synergistic effect between modified epoxy resin, alumina and hydrogen-containing silicone oil, but it uses a large amount of expensive raw materials and has a high density, which is not conducive to the cost optimization and lightweighting of electric vehicles. Patent CN117431032 A discloses a foamed polyurethane sealant composition for batteries and its preparation method. It uses macromolecular polyether polyol, polyester ether and cross-linking agent polyether to ensure the mechanical properties and high temperature aging resistance of the product; it uses bio-based polyether polyol to synthesize modified MDI, which improves the hydrophobicity and moisture and heat resistance of the product, but its red phosphorus flame retardant is easily oxidized and releases harmful and highly toxic gases, and the dust generated by combustion is easy to cause explosion. In view of the current research status, it is of great significance to provide a polyurethane potting glue with excellent performance, environmental protection and simple preparation process. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a two-component hydrophobic and heat-resistant polyurethane potting adhesive, wherein a hydrophobic and heat-resistant siloxane-silicon chain segment is introduced into a polyether polyol structure through acrylic bridging to obtain a siloxane-modified polyether polyol; more side ethyl and phenyl chain segments are introduced into the molecular structure of the polyether polyol through the selection of polymerization monomers; and a starter polyether containing a neopentyl structure is selected to further increase the hydrophobic group content of the raw material, thereby making the polyurethane potting adhesive exhibit excellent hydrophobicity and heat resistance.

[0005] Another object of the present invention is to provide a method for preparing a two-component hydrophobic heat-resistant polyurethane potting adhesive, which has a simple process and is easy to mass produce.

[0006] The two-component hydrophobic heat-resistant polyurethane potting adhesive of the present invention is prepared by reacting component A and component B;

[0007] The A component is composed of the following raw materials in parts by weight:

[0008] Modified polyether polyol I: 17-33 parts;

[0009] Modified polyether polyol II: 15-27 parts;

[0010] Diisocyanate: 18-30 parts;

[0011] Plasticizer: 20~34 parts;

[0012] The B component is composed of the following raw materials in parts by weight:

[0013] Polyether polyol III 47-64 parts;

[0014] Filler: 36~53 parts;

[0015] Catalyst: 0.15~0.35 parts;

[0016] The mass ratio of component A to component B is (2.2-2.6):1;

[0017] The preparation steps of the modified polyether polyol I are as follows: after reacting hydroxyethyl acrylate and toluene diisocyanate, a trifunctional polyether polyol (1) is added to react, and after the reaction is completed, hydrogen-containing silicone oil is added to carry out an addition reaction to obtain the modified polyether polyol I;

[0018] The preparation steps of the modified polyether polyol II are as follows: after reacting hydroxyethyl acrylate and toluene diisocyanate, a hexafunctional polyether polyol (2) is added to react, and after the reaction is completed, hydrogen-containing silicone oil is added to carry out an addition reaction to obtain the modified polyether polyol II;

[0019] The polyether polyol III is a small molecule polyether polyol containing a neopentyl structure.

[0020] The trifunctional polyether polyol (1) is obtained by polymerizing propylene oxide and styrene oxide with trimethylolpropane as an initiator under the action of a catalyst, wherein the mass ratio of propylene oxide to styrene oxide is 9:1, and the number average molecular weight is 3000 g·mol -1 The hexafunctional polyether polyol (2) is obtained by polymerizing propylene oxide and butylene oxide with sorbitol as the initiator in the presence of a catalyst, wherein the mass ratio of propylene oxide to butylene oxide is 3:1 and the number average molecular weight is 3500 g·mol -1 .

[0021] The preparation steps of the modified polyether polyol I are as follows: add hydroxyethyl acrylate into a reaction container, heat it to 70-80°C, add toluene diisocyanate to react, react for 2-3 hours, and the infrared test wave number is 1720cm -1 After the -NCO peak size remains unchanged, polyether polyol (1) is added to react for 3-4 hours. The infrared test wave number is 1720cm -1 After the -NCO peak disappears, add hydrogenated silicone oil for addition reaction. The reaction lasts for 3-4 hours. The infrared test wave number is 1640cm -1After the carbon-carbon double bond peak disappears, the addition reaction is completed to obtain modified polyether polyol I; the molar ratio of hydroxyethyl acrylate, toluene diisocyanate, polyether polyol (1) and hydrogen-containing silicone oil is 1: (0.95-0.98): 1: (1.02-1.05);

[0022] The preparation steps of the modified polyether polyol II are as follows: hydroxyethyl acrylate is added into a reaction container, the temperature is raised to 70-80°C, toluene diisocyanate is added for reaction, the reaction is carried out for 2-3 hours, and the infrared test wave number is 1720cm -1 After the -NCO peak size remains unchanged, polyether polyol (2) is added to react for 3-4 hours. The infrared test wave number is 1720 cm -1 After the -NCO peak disappears, add hydrogenated silicone oil for addition reaction. The reaction lasts for 3-4 hours. The infrared test wave number is 1640cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed and modified polyether polyol II is obtained; the molar ratio of hydroxyethyl acrylate, toluene diisocyanate, polyether polyol (2) and hydrogen-containing silicone oil is 3: (2.85-2.94): 1: (3.06-3.15).

[0023] The structural formula of the hydrogen-containing silicone oil is shown in the following formula I:

[0024]

[0025] Formula I.

[0026] The small molecule polyether polyol containing neopentyl structure includes TMP polyether and NPG polyether. The TMP polyether is obtained by polymerizing propylene oxide with trimethylolpropane as the initiator under the action of KOH catalyst, and the number average molecular weight is 308g·mol -1 The NPG polyether is obtained by polymerizing propylene oxide with neopentyl glycol as the initiator under the action of KOH catalyst, and the number average molecular weight is 218g·mol -1 .

[0027] The diisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0028] The plasticizer is one or more of propylene carbonate, triethyl phosphate and dicyclohexyl phthalate.

[0029] The filler is one or more of fumed silica, methyl MQ resin or calcium carbonate.

[0030] The catalyst is one of dibutyltin dilaurate, dioctyltin dilaurate or organic bismuth.

[0031] The preparation method of the two-component hydrophobic heat-resistant polyurethane potting adhesive of the present invention comprises the following steps:

[0032] S1. Add modified polyether polyol I, modified polyether polyol II and diisocyanate into a reaction container, heat to 75-85°C and keep warm for 2 hours, test the -NCO content to be 7.6-12.3wt.%, then add plasticizer, stir for 0.5-1 hour, cool down, discharge, seal and store, and obtain component A;

[0033] S2: Add polyether polyol III and filler into a three-necked flask, heat to 100-110°C, evacuate to -0.09-0.08MPa and dehydrate for 1.5-2h until the moisture content is less than 0.05wt.%, cool to 20-30°C, add catalyst, stir evenly, and then package under nitrogen protection to obtain component B;

[0034] S3: Evenly mix component A and component B at room temperature and perform curing to obtain a two-component hydrophobic and heat-resistant polyurethane potting adhesive.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The modified polyether polyol of the present invention is prepared by introducing hydrophobic and temperature-resistant siloxane segments into the polyether polyol structure through acrylic acid bridging. At the same time, more side ethyl and phenyl segments are introduced into the molecular structure of the polyether polyol during the polymerization process by selecting the polymerization monomer, thereby further improving the hydrophobic and temperature-resistant properties of the material itself. There is no need to add a large amount of thermal conductive fillers or waterproofing agents, which reduces the compatibility problems of adhesives, performance loss and precipitation risks that may be caused by additives, and improves the stability and service life of the product.

[0037] (2) The polyether polyol III described in the present invention adopts a small molecule polyether polyol containing a neopentyl structure. This neopentyl structure can provide shield protection in the molecular chain, so that the polyurethane potting adhesive prepared with this structure as raw material has excellent thermal stability and weather resistance.

[0038] (3) The entire preparation reaction process described in the present invention is carried out under mild conditions, the operation steps are simple and easy to perform and control, and is suitable for industrial large-scale production. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the embodiments.

[0040] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0041] Some of the raw materials used in the examples and comparative examples are described as follows:

[0042] INOVOL C3050A (functionality 3, number average molecular weight 3000 g·mol -1 , initiator is propylene glycol), Shandong Yinuowei New Materials Co., Ltd.

[0043] INOVOL C350 (glyceryl polyether, functionality 3, number average molecular weight 5000 g·mol -1 ), Shandong Yinuowei New Materials Co., Ltd.

[0044] INOVOL C303T (glyceryl polyether, functionality 3, number average molecular weight 300 g·mol -1 ), Shandong Yinuowei New Materials Co., Ltd.

[0045] Methyl MQ resin, model: DT6102-1H, Guangzhou Delta Silicone Technology Development Co., Ltd.

[0046] Preparation of the trifunctional polyether polyol (1):

[0047] 201 g of trimethylolpropane and 13.7 g of potassium hydroxide catalyst were added to a high-pressure reactor. After nitrogen replacement three times, the temperature was raised to 110°C and dehydrated for 2 h. A mixture of 3936.6 g of propylene oxide and 437.4 g of styrene oxide was continuously added to the reactor. The reaction temperature was controlled to be 110°C and the pressure in the reactor was ≤ 0.3 MPa. After the reaction was completed, the reactor was aged for 4 h and the monomer was removed for 0.5 h. After acid-water refining treatment, a trifunctional polyether polyol (1) was prepared. The hydroxyl value was 56.1 mgKOH / g and the number average molecular weight was 3000 g·mol -1 .

[0048] Preparation of the hexafunctional polyether polyol (2):

[0049] 273 g of sorbitol and 16.1 g of potassium hydroxide catalyst were added to a high-pressure reactor. After nitrogen replacement three times, the temperature was raised to 110° C. and dehydrated for 2 h. A mixture of 3811.5 g of propylene oxide and 1270.5 g of butylene oxide was continuously added to the reactor. The reaction temperature was controlled to be 110° C. The pressure in the reactor was ≤ 0.3 MPa. After the reaction was completed, the reactor was aged for 4 h and the monomer was removed for 0.5 h. After acid-water refining treatment, a hexafunctional polyether polyol (2) was prepared. The hydroxyl value was 96.2 mgKOH / g and the number average molecular weight was 3500 g·mol -1 .

[0050] Preparation of the TMP polyether: 268g of trimethylolpropane and 2.13g of potassium hydroxide catalyst were added to a high-pressure reactor, and the temperature was raised to 110°C after nitrogen replacement three times, and dehydrated for 2h, and 442g of propylene oxide was continuously added to the reactor, and the reaction temperature was controlled to be 110°C, and the pressure in the reactor was ≤0.3MPa. After the reaction was completed, the reactor was aged for 4h, and the monomer was removed for 0.5h. After acid water refining treatment, the TMP polyether was prepared, and the hydroxyl value was 546.4mgKOH / g and the number average molecular weight was 308 g·mol -1 .

[0051] Preparation of the NPG polyether: 416 g of neopentyl glycol and 2.54 g of potassium hydroxide catalyst were added to a high-pressure reactor, and the temperature was raised to 110° C. after nitrogen replacement three times, and dehydration was performed for 2 h. 432 g of propylene oxide was continuously added to the reactor, and the reaction temperature was controlled to be 110° C. The pressure in the reactor was ≤ 0.3 MPa. After the reaction was completed, the reactor was aged for 4 h, and the monomer was removed for 0.5 h. After acid water refining treatment, the NPG polyether was prepared, and the hydroxyl value was 514.7 mgKOH / g and the number average molecular weight was 218 g·mol -1 .

[0052] Example 1

[0053] Preparation of the modified polyether polyol I:

[0054] 19.33 g of hydroxyethyl acrylate was added to a three-necked flask, the temperature was raised to 70 °C, and 28.42 g of toluene diisocyanate was added for reaction. After 2.5 h of reaction, the infrared test wave number was 1720 cm -1 The -NCO peak size remained unchanged. 500 g of polyether polyol (1) was added to react. After 3 h of reaction, the infrared test wave number was 1720 cm -1 The -NCO peak disappeared, and 38.85 g of hydrogenated silicone oil and 0.47 g of chloroplatinic acid catalyst were added for addition reaction. After 3 h of reaction, the infrared test wave number was 1640 cm -1 The carbon-carbon double bond peak at 147° disappears, the addition reaction is completed, and modified polyether polyol Ⅰ is obtained;

[0055] Preparation of the modified polyether polyol II:

[0056] 49.71 g of hydroxyethyl acrylate was added to a three-necked flask, the temperature was raised to 70 °C, and 73.08 g of toluene diisocyanate was added for reaction for 2.5 h. The infrared test wave number was 1720 cm -1 After the -NCO peak size remained unchanged, 500 g of polyether polyol (2) was added to react for 3 h. The infrared test wave number was 1720 cm -1After the -NCO peak disappeared, 99.9 g of hydrogenated silicone oil and 0.58 g of chloroplatinic acid catalyst were added for addition reaction for 3 h. The infrared test wave number was 1640 cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed and modified polyether polyol II is obtained.

[0057] The preparation method of the two-component hydrophobic heat-resistant potting glue comprises the following steps:

[0058] S1. Add 100g of modified polyether polyol I, 108g of modified polyether polyol II and 112g of toluene diisocyanate into a three-necked flask, heat to 80°C and keep warm for 2h. The -NCO content is tested to be 12.3 wt.%, then add 25g of propylene carbonate and 55g of triethyl phosphate, stir for 1h, cool down, discharge, seal and store, and obtain component A.

[0059] S2: Add 256g of TMP polyether, 90g of fumed silica and 54g of methyl MQ resin into a three-necked flask, heat to 100°C, evacuate to -0.09MPa for dehydration for 2h, test the moisture content to be 0.029wt.%, cool to 25°C, add 1g of dibutyltin dilaurate, stir evenly, and then package under nitrogen protection to obtain component B;

[0060] S3: Mix component A and component B at a mass ratio of 2.2:1 at room temperature, and then cure them to obtain a two-component hydrophobic and heat-resistant polyurethane potting adhesive.

[0061] Example 2

[0062] The preparation steps of the modified polyether polyol I are as follows: 19.33 g of hydroxyethyl acrylate is added into a three-necked flask, the temperature is raised to 75°C, 27.84 g of toluene diisocyanate is added for reaction, and the infrared test wave number is 1720 cm after 2 hours of reaction. -1 The -NCO peak size remained unchanged. 500 g of polyether polyol (1) was added to react. After 3 h of reaction, the infrared test wave number was 1720 cm -1 The -NCO peak disappeared, and 38.11 g of hydrogenated silicone oil and 0.47 g of chloroplatinic acid catalyst were added for addition reaction. After 3 h of reaction, the infrared test wave number was 1640 cm -1 The carbon-carbon double bond peak disappears, the addition reaction is completed, and modified polyether polyol Ⅰ is obtained.

[0063] The preparation steps of the modified polyether polyol II are as follows: 49.71 g of hydroxyethyl acrylate is added into a three-necked flask, the temperature is raised to 75°C, 71.59 g of toluene diisocyanate is added for reaction, the reaction is carried out for 2 hours, and the infrared test wave number is 1720 cm -1After the -NCO peak size remained unchanged, 500 g of polyether polyol (2) was added to react for 3 h. The infrared test wave number was 1720 cm -1 After the -NCO peak disappeared, 98.0 g of hydrogenated silicone oil and 0.58 g of chloroplatinic acid catalyst were added for addition reaction for 3 h. The infrared test wave number was 1640 cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed and modified polyether polyol II is obtained.

[0064] The preparation method of the two-component hydrophobic thermally conductive potting glue comprises the following steps:

[0065] S1. Add 68g of modified polyether polyol I, 96g of modified polyether polyol II and 120g of diphenylmethane diisocyanate into a three-necked flask, heat to 75°C and keep warm for 2h, test the -NCO content to be 9.1 wt.%, then add 53g of triethyl phosphate and 63g of dicyclohexyl phthalate, stir for 1h, cool down and discharge, seal and store, to obtain component A;

[0066] S2: Add 232g of NPG polyether, 80g of methyl MQ resin and 88g of calcium carbonate into a three-necked flask, heat to 110°C, evacuate to -0.09MPa for dehydration for 1.5h, test the moisture content to be 0.037wt.%, cool to 20°C, add 1.4g of dioctyltin dilaurate, stir evenly, and then package under nitrogen protection to obtain component B;

[0067] S3: Mix component A and component B at a mass ratio of 2.5:1 at room temperature, and then cure them to obtain a two-component hydrophobic and heat-resistant polyurethane potting adhesive.

[0068] Example 3

[0069] The preparation steps of the modified polyether polyol I are as follows: 19.33 g of hydroxyethyl acrylate is added into a three-necked flask, the temperature is raised to 80°C, 27.55 g of toluene diisocyanate is added for reaction, and the infrared test wave number after reaction for 3 hours is 1720 cm -1 The -NCO peak size at the position remained unchanged. 500 g of polyether polyol (1) was added to react. After 4 h of reaction, the infrared test wave number was 1720 cm -1 The -NCO peak disappeared, and 37.74 g of hydrogenated silicone oil and 0.47 g of chloroplatinic acid catalyst were added for addition reaction. After 4 h of reaction, the infrared test wave number was 1640 cm -1 The carbon-carbon double bond peak disappears, the addition reaction is completed, and modified polyether polyol Ⅰ is obtained.

[0070] The preparation steps of the modified polyether polyol II are as follows: 49.71 g of hydroxyethyl acrylate is added into a three-necked flask, the temperature is raised to 80°C, 70.84 g of toluene diisocyanate is added for reaction, the reaction is carried out for 3 hours, and the infrared test wave number is 1720 cm -1 After the -NCO peak size remained unchanged, 500 g of polyether polyol (2) was added to react for 4 h. The infrared test wave number was 1720 cm -1 After the -NCO peak disappeared, 97.05 g of hydrogenated silicone oil and 0.58 g of chloroplatinic acid catalyst were added for addition reaction for 4 h. The infrared test wave number was 1640 cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed and modified polyether polyol II is obtained.

[0071] The preparation method of the two-component hydrophobic thermally conductive potting glue comprises the following steps:

[0072] S1. Add 132g of modified polyether polyol I, 60g of modified polyether polyol II and 72g of toluene diisocyanate into a three-necked flask, heat to 85°C and keep warm for 2h, test the -NCO content to be 7.6 wt.%, then add 72g of propylene carbonate and 64g of dicyclohexyl phthalate, stir for 0.5h, cool down and discharge, seal and store, to obtain component A;

[0073] S2: Add 188g of NPG polyether, 103g of fumed silica and 109g of calcium carbonate into a three-necked flask, heat to 100°C, evacuate to -0.08MPa for dehydration for 2h, test the moisture content to be 0.021wt.%, cool to 30°C, add 0.6g of organic bismuth catalyst DY-20, stir evenly, and then package under nitrogen protection to obtain component B;

[0074] S3: Mix component A and component B at a mass ratio of 2.6:1 at room temperature, and then cure them to obtain a two-component hydrophobic and heat-resistant polyurethane potting adhesive.

[0075] Comparative Example 1

[0076] INOVOL C3050A was used to replace polyether polyol (1) to synthesize modified polyether polyol I. The preparation steps were the same as those of modified polyether polyol I described in Example 1. Other raw materials and preparation methods were the same as those in Example 1.

[0077] Comparative Example 2

[0078] The number average molecular weight was 3500 g·mol -1The sorbitol-based polyether polyol (prepared by catalyzing the polymerization of propylene oxide with sorbitol as the initiator) is substituted for the polyether polyol (2) in Example 1. The preparation steps are the same as those of the polyether polyol (2) described in Example 1. Other raw materials and preparation methods are the same as those in Example 1.

[0079] Comparative Example 3

[0080] The number average molecular weight was 3500 g·mol -1 The modified polyether polyol I in Example 1 is replaced by a propylene glycol-based polyether polyol (prepared by catalyzing the polymerization of propylene oxide under the action of a catalyst with propylene glycol as an initiator), and other raw materials and preparation methods are the same as those in Example 1.

[0081] Comparative Example 4

[0082] INOVOL C350 was used to replace the modified polyether polyol II in Example 1. Other raw materials and preparation methods were the same as in Example 1.

[0083] Comparative Example 5

[0084] INOVOL C303T was used to replace the TMP polyether in Example 1. Other raw materials and preparation methods were the same as those in Example 1.

[0085] Comparative Example 6

[0086] The number average molecular weight was 3500 g·mol -1 The modified polyether polyol I in Example 1 is replaced by propylene glycol-based polyether polyol (prepared by catalyzing the polymerization of propylene oxide under the action of a catalyst with propylene glycol as an initiator), and INOVOL C350 is used to replace the modified polyether polyol II in Example 1. Other raw materials and preparation methods are the same as those in Example 1.

[0087] The performance tests were performed on the polyurethane potting adhesives prepared in Examples 1 to 3 and Comparative Examples 1 to 6, respectively, and the test methods were as follows:

[0088] The water contact angle is tested according to GB / T 30693-2014.

[0089] The 30-day water absorption rate is tested according to GB / T 19250-2013;

[0090] The initial thermal decomposition temperature (°C) was measured using a differential scanning calorimeter.

[0091] The test results are shown in Table 1.

[0092] Table 1 Performance test results

[0093]

[0094] As can be seen from the data in Table 1, the introduction of low surface energy siloxane into the cross-linked network structure of the potting glue can significantly improve the hydrophobicity and heat resistance of the material (Comparative Examples 3 and 4). In addition, the introduction of the benzene ring structure can improve the heat resistance of the material. At the same time, the polyether polyol III containing the neopentyl structure can provide shield protection in the molecular chain, further increasing the content of the hydrophobic group of the raw material, thereby making the polyurethane potting glue prepared with this structure as the raw material have excellent thermal stability and weather resistance. The improvement of the above performance can greatly enrich the application scenarios of the potting glue in outdoor or harsh environmental conditions.

Claims

1. A two-component hydrophobic heat-resistant polyurethane potting adhesive, characterized in that: Prepared by reaction of component A and component B; The A component is composed of the following raw materials in parts by weight: Modified polyether polyol I: 17-33 parts; Modified polyether polyol II: 15-27 parts; Diisocyanate: 18-30 parts; Plasticizer: 20~34 parts; The B component is composed of the following raw materials in parts by weight: Polyether polyol III 47-64 parts; Filler: 36~53 parts; Catalyst: 0.15~0.35 parts; The mass ratio of component A to component B is (2.2-2.6):1; The preparation steps of the modified polyether polyol I are as follows: after reacting hydroxyethyl acrylate and toluene diisocyanate, a trifunctional polyether polyol (1) is added to react, and after the reaction is completed, hydrogen-containing silicone oil is added to carry out an addition reaction to obtain the modified polyether polyol I; The preparation steps of the modified polyether polyol II are as follows: after reacting hydroxyethyl acrylate and toluene diisocyanate, a hexafunctional polyether polyol (2) is added to react, and after the reaction is completed, hydrogen-containing silicone oil is added to carry out an addition reaction to obtain the modified polyether polyol II; The polyether polyol III is a small molecule polyether polyol containing a neopentyl structure; The trifunctional polyether polyol (1) is obtained by polymerizing propylene oxide and styrene oxide with trimethylolpropane as an initiator in the presence of a catalyst; The hexafunctional polyether polyol (2) is obtained by polymerizing propylene oxide and butylene oxide with sorbitol as an initiator in the presence of a catalyst.

2. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The number average molecular weight of the trifunctional polyether polyol (1) is 3000 g·mol -1 The number average molecular weight of the hexafunctional polyether polyol (2) is 3500 g·mol -1 .

3. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The preparation steps of the modified polyether polyol I are as follows: hydroxyethyl acrylate is added into a reaction vessel, the temperature is raised to 70-80°C, toluene diisocyanate is added for reaction, and the infrared test wave number is 1720cm -1 After the -NCO peak size remained unchanged, polyether polyol (1) was added to react. The infrared test wave number was 1720 cm -1 After the -NCO peak disappears, hydrogenated silicone oil is added for addition reaction. The infrared test wave number is 1640cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed to obtain modified polyether polyol I; the molar ratio of hydroxyethyl acrylate, toluene diisocyanate, polyether polyol (1) and hydrogen-containing silicone oil is 1: (0.95-0.98): 1: (1.02-1.05); The preparation steps of the modified polyether polyol II are as follows: hydroxyethyl acrylate is added into a reaction vessel, the temperature is raised to 70-80°C, toluene diisocyanate is added for reaction, and the infrared test wave number is 1720cm -1 After the -NCO peak size remained unchanged, polyether polyol (2) was added to react. The infrared test wave number was 1720 cm -1 After the -NCO peak disappears, hydrogenated silicone oil is added for addition reaction. The infrared test wave number is 1640cm -1 After the carbon-carbon double bond peak disappears, the addition reaction is completed and modified polyether polyol II is obtained; the molar ratio of hydroxyethyl acrylate, toluene diisocyanate, polyether polyol (2) and hydrogen-containing silicone oil is 3: (2.85-2.94): 1: (3.06-3.15).

4. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The structural formula of the hydrogen-containing silicone oil is shown in the following formula I: Formula I.

5. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The small molecule polyether polyol containing neopentyl structure includes TMP polyether and NPG polyether. The TMP polyether is obtained by polymerizing propylene oxide with trimethylolpropane as initiator under the action of catalyst; the NPG polyether is obtained by polymerizing propylene oxide with neopentyl glycol as initiator under the action of catalyst.

6. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The diisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

7. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The plasticizer is one or more of propylene carbonate, triethyl phosphate and dicyclohexyl phthalate.

8. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The filler is one or more of fumed silica, methyl MQ resin or calcium carbonate.

9. The two-component hydrophobic heat-resistant polyurethane potting adhesive according to claim 1, characterized in that: The catalyst is one of dibutyltin dilaurate, dioctyltin dilaurate or organic bismuth.

10. A method for preparing the two-component hydrophobic heat-resistant polyurethane potting adhesive according to any one of claims 1 to 9, characterized in that: Here are the steps: S1. Add modified polyether polyol I, modified polyether polyol II and diisocyanate into a reaction container, heat to 75-85°C for reaction, test the -NCO content to be 7.6-12.3 wt.%, then add plasticizer, stir, cool down, discharge, seal and store, to obtain component A; S2: Add polyether polyol III and filler into a three-necked flask, heat to 100-110°C, vacuum dehydrate, cool to 20-30°C, add catalyst, stir evenly, and obtain component B; S3: Evenly mix component A and component B at room temperature and perform curing to obtain a two-component hydrophobic and heat-resistant polyurethane potting adhesive.

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