Environment-friendly two-component polyurethane pouring sealant and preparation method thereof

Abstract

The invention discloses an environment-friendly two-component polyurethane pouring sealant and a preparation method thereof. The two-component polyurethane pouring sealant comprises a component A and a component B, the component A is prepared by compounding the following raw materials: polyether polyol, a macromolecular reaction type brominated flame retardant, a defoaming agent, black paste and a catalyst; and the component B is prepared by compounding the following raw materials: isocyanate, an isocyanate-terminated polyether polyol prepolymer and a defoaming agent. According to the environment-friendly double-component polyurethane pouring sealant, the macromolecular hydroxyl-containing reactive liquid brominated flame retardant is added, so that on one hand, the viscosity, the density and the hardness of the polyurethane pouring sealant are greatly reduced, and a pouring process and light weight are facilitated; on the other hand, the flame retardant can have good compatibility with polyether polyol in the component A, migration and precipitation of tetrabromobisphenol A are reduced after the flame retardant reacts with isocyanate in the component B, toxicity is reduced, environment friendliness is improved, and the flame retardance of the flame retardant is not reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of two-component flame-retardant polyurethane pouring sealant, in particular to a two-component polyurethane pouring sealant containing an environmentally friendly bromine-based flame retardant and a preparation method thereof. BACKGROUND

[0002] Circuit boards will be affected by external moisture, temperature and external force and other environmental factors during use, causing performance degradation and affecting the stability of electronic products. Therefore, sealing and protection materials are used in the production process of circuit boards. Polyurethane pouring sealant not only has mechanical adjustability, but also has excellent elasticity and insulation, and has a wide application in the field of circuit board pouring and protection. With the rapid development of modern electronic industry, the performance requirements of circuit boards are becoming higher and higher, and the performance of polyurethane pouring sealant is also being demanded higher and higher. There is a fire hazard in the use of circuit boards, so the flame retardance of polyurethane pouring sealant has certain requirements.

[0003] At present, inorganic filler type flame retardants are mostly used in the field of flame-retardant polyurethane. Although inorganic filler type flame retardants are widely used and low in price, they need to be added in an amount of more than 40% to achieve V0 level flame retardation effect, and they are prone to bring the disadvantage of large density which is not conducive to lightweight. In addition, inorganic powder also has the disadvantage of easy settlement. At present, some new phosphorus-nitrogen powder type flame retardants are also applied. This kind of flame retardant has the advantages of low density and small particle size, but it is expensive and difficult to be widely applied. Bromine-based flame retardants, mainly tetra-bromobisphenol A, are low in price and high in flame retardant efficiency. The bromine atom content of 10-20% can achieve V0 level. It can also be dissolved in polyurethane pouring sealant, thereby reducing the density of the pouring sealant. Although it is widely used, tetra-bromobisphenol A cannot meet the international environmental protection requirements if there is residual amount not involved in the reaction, which also limits its application. Because tetra-bromobisphenol A is a flame retardant, it will produce harmful substances to the environment, so the development of polyurethane pouring sealant containing environmentally friendly bromine-based flame retardant system has become the focus of research. In addition, tetra-bromobisphenol A itself has a rigid benzene ring structure, which will gradually show high rigidity and brittleness after the curing of polyurethane pouring sealant, limiting the flexibility and elasticity of the material, and being not conducive to the high and low temperature resistance.

[0004] In view of the problems existing in the prior art, it is of great significance to develop a polyurethane pouring sealant with low density, good flexibility and excellent flame retardant performance to meet the requirements of modern industry for flame-retardant materials. SUMMARY

[0005] The application aims to provide an environmentally friendly two-component polyurethane pouring sealant and a preparation method thereof, so as to solve the above technical problems in the prior art. The two-component polyurethane pouring sealant provided by the application is composed of A component and B component, the viscosity and density of the polyurethane pouring sealant can be greatly reduced by adding a self-made macromolecular polymerization type liquid bromine flame retardant in the A component, which is beneficial to the pouring process and light weight; the molecular chain length of tetrabromobisphenol A is increased by molecular synthesis, and the molecular flexibility is increased by containing ether bonds, ester groups and long-chain alkyl groups, so that the hardness of the polyurethane pouring sealant is reduced; the molecular of the flame retardant contains hydroxyl groups, which has good compatibility with the polyether polyol in the A component, and the migration and precipitation of tetrabromobisphenol A are reduced after the isocyanate reaction with the B component, so that the toxicity is reduced, the environmental protection is improved, and the flame retardancy is not reduced.

[0006] The application is achieved by the following technical solutions.

[0007] An environmentally friendly two-component polyurethane pouring sealant comprises A component and B component.

[0008] The A component is prepared by compounding the following raw materials in parts by mass: polyether polyol 30-60 parts, macromolecular reaction type bromine flame retardant 30-70 parts, defoaming agent 0.01-0.2 parts, black paste 0.5-2 parts, and catalyst 0.01-0.1 parts.

[0009] The B component is prepared by compounding the following raw materials in parts by mass: isocyanate 10-30 parts, terminal isocyanate polyether polyol prepolymer 50-90 parts, and defoaming agent 0.01-0.2 parts.

[0010] Preferably, the polyether polyol in the A component is one or more of polyether polyols with a molecular weight of 400-3000.

[0011] Preferably, the polyether polyol is selected from one or more of castor oil, soybean oil, polyoxypropylene glycol, polyoxypropylene triol, polyoxyethylene glycol, polyoxyethylene triol, and polytetrahydrofuran ether polyol.

[0012] Preferably, the macromolecular reaction type bromine flame retardant in the A component has a molecular structure as shown in the following formula:

[0013]

[0014] Preferably, the macromolecular reaction type bromine flame retardant has a molecular weight of 1370.25 g / mol and a viscosity of 200-500 mPa·s at 25℃.

[0015] The macromolecular reaction type bromine flame retardant is prepared by the following method:

[0016] S1: 100 parts by mass of tetrabromobisphenol A, 50-60 parts by mass of methyltetrahydrophthalic anhydride are added to a reaction kettle, and stirred at 80-100°C for 1-2 hours to make tetrabromobisphenol A fully dissolved in methyltetrahydrophthalic anhydride, and then heated to 150-160°C for 2-3 hours;

[0017] S2: 110-120 parts by mass of C14 alkyl glycidyl ether is added to a reaction kettle, and reacted at 120-150°C for 1-2 hours to obtain a macromolecular reaction type bromine flame retardant.

[0018] In the above method, tetrabromobisphenol A has a molecular structure as shown in the following formula:

[0019]

[0020] In the above method, methyltetrahydrophthalic anhydride has a molecular structure as shown in the following formula:

[0021]

[0022] Preferably, the C14 alkyl glycidyl ether glycidyl ether in the above method has a molecular structure as shown in the following formula:

[0023]

[0024] Preferably, the defoaming agent in the A component is an organic silicon-based defoaming agent;

[0025] Preferably, the black paste in the A component is a low-viscosity polyether polyol treated carbon black;

[0026] Preferably, the catalyst in the A component is an organic metal catalyst;

[0027] Preferably, the isocyanate in the B component is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, carbodiimide modified MDI, toluene diisocyanate, and MDI dimer;

[0028] Preferably, the terminal isocyanate-based polyurethane prepolymer in the B component is obtained by reacting a polyether diol and an isocyanate;

[0029] Preferably, the raw material polyether diol of the terminal isocyanate-based polyurethane prepolymer in the B component is one or more of polypropylene oxide diol, polyethylene oxide diol, tetrahydrofuran copolymer diol, and propylene oxide-ethylene oxide block copolymer diol;

[0030] Preferably, the raw isocyanate of the terminal isocyanate group polyurethane prepolymer in the B component is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, carbodiimide modified MDI, toluene diisocyanate, MDI dimer;

[0031] Preferably, the defoaming agent in the B component is a silicone-based defoaming agent;

[0032] A preparation method of the above-mentioned environmentally friendly two-component polyurethane pouring sealant, and the specific method is as follows:

[0033] The A component and the B component are prepared respectively, wherein,

[0034] The A component is prepared as follows:

[0035] S1: The formula amount of polyether polyol is added to a reaction kettle, stirred at 100-120 DEG C and vacuum dehydrated for 1-2h;

[0036] S2: The temperature is reduced to 40-60 DEG C, the macromolecular reaction type bromine flame retardant, the defoaming agent, the black paste and the catalyst are added and stirred for 60-90 min to obtain the A component;

[0037] Preparation of the B component:

[0038] The formula amount of terminal isocyanate polyether polyol prepolymer is added to a reaction kettle, the temperature is controlled to 25-40 DEG C, the formula amount of other isocyanate and defoaming agent is added, and stirring is carried out for 60-90 min to obtain the B component;

[0039] The preparation process of the terminal isocyanate polyether polyol prepolymer is as follows: the formula amount of polyether dihydric alcohol is added to a reaction kettle, stirred at 100-120 DEG C and vacuum dehydrated for 1-2h, the temperature is reduced to 50-70 DEG C, the formula amount of isocyanate is added, the temperature is increased to 80-90 DEG C, and stirring is continuously carried out for 1-2h until the titration NCO content no longer changes to end the reaction;

[0040] The mass fraction of polyether dihydric alcohol in the preparation process of the terminal isocyanate polyether polyol prepolymer is 30-40 parts, and the mass fraction of isocyanate is 34-65 parts;

[0041] The prepared A component and B component are stirred according to the mass ratio of 100:20-40, mixed uniformly and deaerated to obtain the environmentally friendly two-component polyurethane pouring sealant.

[0042] Compared with the prior art, the environmentally friendly two-component polyurethane pouring sealant and the preparation method thereof provided by the application at least have the following advantages:

[0043] (1) This invention uses tetrabromobisphenol A to synthesize a macromolecular reactive bromine flame retardant through molecular design. The macromolecular reactive bromine flame retardant is a liquid, which can significantly reduce the viscosity and density of polyurethane potting compound, which is beneficial to potting process and lightweighting, and has no sedimentation problem.

[0044] (2) This invention modifies tetrabromobisphenol A into a macromolecule through molecular design, introducing a large number of polar hydroxyl groups, ether bonds, and other groups into the molecular structure, which significantly improves the intermolecular interaction. On the one hand, this structure enables the tetrabromobisphenol A derivative and the polyether polyol to be tightly bound together by intermolecular forces such as hydrogen bonds and van der Waals forces, which not only effectively avoids the phase separation problem, but also enables the two materials to be uniformly dispersed at the molecular level, thereby improving the overall stability and uniformity of the material. This good compatibility can ensure the uniform distribution of the flame retardant, give full play to the flame retardant effect, avoid the problem of local flame retardant failure caused by uneven dispersion of the flame retardant, and also help to improve the processing performance and product quality of the material. On the other hand, after reacting with the isocyanate of component B, the migration and precipitation of tetrabromobisphenol A are reduced, the toxicity is reduced, the environmental friendliness is improved, and the flame retardancy is not reduced.

[0045] (3) Tetrabromobisphenol A itself has a rigid benzene ring structure, which gradually exhibits high rigidity and brittleness after the polyurethane potting compound is cured, limiting the material's flexibility and elasticity and hindering its resistance to high and low temperatures. The environmentally friendly brominated flame retardant synthesized in this invention introduces flexible ether bonds (-O-) and long-chain alkyl structures. The ether bonds have a low internal rotation barrier, making it easier for the molecular chains to rotate and undergo conformational changes, thus increasing the flexibility of the molecular chains. The long-chain alkyl structures act like plasticizers, weakening the interaction forces between polymer chains and allowing the molecular chains to move more freely. These structural changes work together to significantly reduce the rigidity of the material and significantly improve the flexibility of the polyurethane potting compound after curing.

[0046] (4) The polyurethane potting compound prepared by curing components A and B of the present invention has lower hardness and better insulation. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them, and do not constitute a limitation on the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0048] First, the following explanations are provided for the terms that may be used in this article:

[0049] The terms “including,” “comprising,” “containing,” “having,” or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, “including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.)” should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0050] The term "parts by weight" indicates the mass ratio between multiple components. For example, if component X is described as x parts by weight and component Y as y parts by weight, then the mass ratio of component X to component Y is x:y. One part by weight can represent any mass; for example, one part by weight can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by weight of all components is not necessarily 100 parts; it can be greater than 100 parts, less than 100 parts, or equal to 100 parts. Unless otherwise stated, parts, proportions, and percentages mentioned herein are all by mass.

[0051] When concentration, temperature, pressure, size, or other parameters are expressed as numerical ranges, such ranges should be understood to specifically disclose all ranges formed by any pairing of upper limits, lower limits, or preferred values ​​within that range, regardless of whether the range is explicitly stated; for example, if the numerical range "2 to 8" is stated, then that range should be interpreted to include ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise stated, the numerical ranges described herein include both their endpoints and all integers and fractions within that range.

[0052] The following is a detailed description of a two-component polyurethane potting compound containing an environmentally friendly brominated flame retardant and its preparation method provided by the present invention. Contents not described in detail in the embodiments of the present invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of the present invention, they should be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the present invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0053] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of an environmentally friendly two-component polyurethane potting compound and its preparation method is provided by the present invention using specific embodiments.

[0054] Example 1

[0055] An environmentally friendly two-component polyurethane potting compound, the preparation method of which includes:

[0056] 1) The dosage of each component is based on parts by weight.

[0057] 2) Preparation of macromolecular reactive bromine-based flame retardants:

[0058] S1: Add 100 parts by mass of tetrabromobisphenol A and 55 parts by mass of methyltetrahydrophthalic anhydride to the reaction vessel, stir at 90°C for 2 hours to fully dissolve tetrabromobisphenol A in methyltetrahydrophthalic anhydride, and then heat to 150°C and react for 2 hours.

[0059] S2: Add 110 parts by mass of C14 alkyl glycidyl ether to the reactor and react at 120°C for 1 hour to obtain a macromolecular reactive brominated flame retardant.

[0060] 3) Preparation of component A:

[0061] S1: Add 26.9 parts castor oil and 9.3 parts polyoxypropylene glycol with a molecular weight of 400 to the reactor, stir and vacuum dehydrate at 120°C for 2 hours;

[0062] S2: When the temperature is reduced to 50℃, add 62.3 parts of macromolecular reactive bromine flame retardant, 0.05 parts of defoamer A535, 1.5 parts of black paste 9007EH, and 0.05 parts of dimethylimidazole catalyst and stir for 60 min to obtain component A;

[0063] 4) Preparation of component B:

[0064] S1: Add 34.7 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 35.6 parts of carbodiimide modified MDI, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes to obtain isocyanate-terminated polyether polyol prepolymer;

[0065] S2: Control the temperature to 40℃, add 29.6 parts of diphenylmethane diisocyanate and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0066] The prepared components A and B are mixed at a weight ratio of 100:40 to obtain an environmentally friendly two-component polyurethane potting compound.

[0067] Example 2

[0068] An environmentally friendly two-component polyurethane potting compound, the preparation method of which includes:

[0069] 1) The dosage of each component is based on parts by weight.

[0070] 2) Preparation of macromolecular reactive bromine-based flame retardants:

[0071] S1: Add 100 parts by mass of tetrabromobisphenol A and 60 parts by mass of methyltetrahydrophthalic anhydride to the reaction vessel, stir at 90°C for 2 hours to fully dissolve tetrabromobisphenol A in methyltetrahydrophthalic anhydride, and then heat to 150°C and react for 2 hours.

[0072] S2: Add 115 parts by mass of C14 alkyl glycidyl ether to the reactor and react at 120°C for 1 hour to obtain a macromolecular reactive brominated flame retardant.

[0073] 3) Preparation of component A:

[0074] S1: Add 23.7 parts castor oil and 10 parts polyoxypropylene triol with a molecular weight of 420 to the reaction vessel, stir and vacuum dehydrate at 120°C for 2 hours;

[0075] S2: When the temperature is reduced to 50℃, add 65.2 parts of macromolecular reactive bromine flame retardant, 0.1 parts of defoamer A535, 1.0 parts of black paste 9007EH, and 0.02 parts of dimethylimidazole catalyst and stir for 60 min to obtain component A;

[0076] 4) Preparation of component B:

[0077] S1: Add 36 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 34.3 carbodiimide-modified MDI, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes to obtain isocyanate-terminated polyether polyol prepolymer;

[0078] S2: Control the temperature to 40℃, add 29.6 parts of diphenylmethane diisocyanate and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0079] The prepared components A and B are mixed at a weight ratio of 100:30 to obtain an environmentally friendly two-component polyurethane potting compound.

[0080] Example 3

[0081] An environmentally friendly two-component polyurethane potting compound, the preparation method of which includes:

[0082] 1) The dosage of each component is based on parts by weight.

[0083] 2) Preparation of macromolecular reactive bromine-based flame retardants:

[0084] S1: Add 100 parts by mass of tetrabromobisphenol A and 53 parts by mass of methyltetrahydrophthalic anhydride to the reaction vessel, stir at 90°C for 2 hours to fully dissolve tetrabromobisphenol A in methyltetrahydrophthalic anhydride, and then heat to 150°C and react for 2 hours.

[0085] S2: Add 110 parts by mass of glycidyl ether C14 alkyl glycidyl ether to the reaction vessel and react at 120°C for 1 hour to obtain a macromolecular reactive brominated flame retardant.

[0086] 3) Preparation of component A:

[0087] S1: Add 21.43 parts of polyoxypropylene triol with a molecular weight of 3000 and 9 parts of polyoxypropylene diol with a molecular weight of 400 to the reaction vessel, stir and dehydrate under vacuum at 120°C for 2 hours.

[0088] S2: When the temperature is reduced to 50℃, add 68 parts of macromolecular reactive bromine flame retardant, 0.02 parts of defoamer A535, 1.5 parts of black paste 9007EH, and 0.05 parts of dimethylimidazole catalyst and stir for 60 min to obtain component A;

[0089] 4) Preparation of component B:

[0090] S1: Add 35 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 35.3 parts of diphenylmethane diisocyanate, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes, to obtain the terminal isocyanate polyether polyol prepolymer;

[0091] S2: Control the temperature to 40℃, add 29.6 parts of carbodiimide MDI and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0092] The prepared components A and B are mixed at a weight ratio of 100:30 to obtain an environmentally friendly two-component polyurethane potting compound.

[0093] Example 4

[0094] An environmentally friendly two-component polyurethane potting compound, the preparation method of which includes:

[0095] 1) The dosage of each component is based on parts by weight.

[0096] 2) Preparation of macromolecular reactive bromine-based flame retardants:

[0097] S1: Add 100 parts by mass of tetrabromobisphenol A and 58 parts by mass of methyltetrahydrophthalic anhydride to the reaction vessel, stir at 90°C for 2 hours to fully dissolve tetrabromobisphenol A in methyltetrahydrophthalic anhydride, and then heat to 150°C and react for 2 hours.

[0098] S2: 112 parts by mass of C14 alkyl glycidyl ether were added to the reactor and reacted at 120°C for 1 hour to obtain a macromolecular reactive brominated flame retardant.

[0099] 3) Preparation of component A:

[0100] S1: Add 21.43 parts of polyoxypropylene triol with a molecular weight of 1000, 6 parts of polyoxypropylene diol with a molecular weight of 2000, and 3 parts of polyoxypropylene triol with a molecular weight of 420 to the reaction vessel, stir and dehydrate under vacuum at 120°C for 2 hours.

[0101] S2: When the temperature is reduced to 50℃, add 68 parts of macromolecular reactive bromine flame retardant, 0.1 parts of defoamer A535, 1.2 parts of black paste 9007EH, and 0.03 parts of dimethylimidazole catalyst and stir for 60 min to obtain component A;

[0102] 4) Preparation of component B:

[0103] S1: Add 40 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 49.3 carbodiimide-modified isocyanate, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes, to obtain the terminal isocyanate polyether polyol prepolymer;

[0104] S2: Control the temperature to 40℃, add 10.6 parts of MDI dimer and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0105] The prepared components A and B are mixed at a weight ratio of 100:25 to obtain an environmentally friendly two-component polyurethane potting compound.

[0106] Comparative Example 1

[0107] A two-component polyurethane potting compound, the preparation method of which includes:

[0108] 1) The dosage of each component is based on parts by weight.

[0109] 2) Preparation of component A:

[0110] S1: Add 21.43 parts of polyoxypropylene triol with a molecular weight of 3000 and 9 parts of polyoxypropylene diol with a molecular weight of 400 to the reaction vessel, stir and dehydrate under vacuum at 120°C for 2 hours.

[0111] S2: When the temperature is reduced to 50℃, add 0.02 parts of defoamer A535, 1.5 parts of black paste 9007EH, and 0.05 parts of dimethylimidazole catalyst and stir for 60 min to obtain component A;

[0112] 4) Preparation of component B:

[0113] S1: Add 35 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 35.3 parts of diphenylmethane diisocyanate, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes, to obtain the terminal isocyanate polyether polyol prepolymer;

[0114] S2: Control the temperature to 40℃, add 29.6 parts of carbodiimide MDI and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0115] The prepared components A and B are mixed at a weight ratio of 100:30 to obtain a two-component polyurethane potting compound.

[0116] Comparative Example 2

[0117] A two-component polyurethane potting compound, the preparation method of which includes:

[0118] 1) The dosage of each component is based on parts by weight.

[0119] 2) Preparation of component A:

[0120] S1: Add 21.43 parts of polyoxypropylene triol with a molecular weight of 3000 and 9 parts of polyoxypropylene diol with a molecular weight of 400 to the reaction vessel, stir and dehydrate under vacuum at 120°C for 2 hours.

[0121] S2: When the temperature is reduced to 50℃, 68 parts of FR606 flame retardant, 0.02 parts of defoamer A535, 1.5 parts of black paste 9007EH, and 0.05 parts of dimethylimidazole catalyst are added and stirred for 60 minutes to obtain component A.

[0122] 4) Preparation of component B:

[0123] S1: Add 35 parts of polyoxypropylene diol with a molecular weight of 2000 to the reactor, stir and dehydrate under vacuum at 120°C for 2 hours, cool down to 70°C, add 35.3 parts of diphenylmethane diisocyanate, heat up to 85°C, stir continuously for 1 hour, and stop the reaction when the NCO content no longer changes, to obtain the terminal isocyanate polyether polyol prepolymer;

[0124] S2: Control the temperature to 40℃, add 29.6 parts of carbodiimide MDI and 0.1 parts of defoamer A535, stir for 60 min to obtain component B;

[0125] The prepared components A and B are mixed at a weight ratio of 100:30 to obtain a two-component polyurethane potting compound.

[0126] The environmentally friendly two-component polyurethane potting compounds prepared in the above embodiments and comparative examples were tested for performance, and the results are shown in the table below.

[0127] Table 1. Performance Test Results of Two-Component Polyurethane Potting Compound

[0128]

[0129]

[0130] As can be seen from Table 1 above, compared with the commercially available product UF-705, Examples 1, 2, 3 and 4 of this invention have lower viscosity, which is beneficial to the potting process. The density is reduced after curing, and they also have excellent flame retardancy and insulation properties.

[0131] Compared with the commercially available product SD-1004, the flame retardancy of this invention can reach the UL94-V0 level, and its insulation is also superior to that of the commercially available product SD-1004.

[0132] Compared with Comparative Examples 1 and 2, Examples 1, 2, 3 and 4 of the present invention have lower viscosity, lower post-curing density and excellent flame retardancy.

[0133] In summary, the present invention has lower density, better flame retardancy and insulation.

[0134] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. An environmentally friendly two-component polyurethane potting compound, characterized in that, include: Component A and Component B; Component A is formulated from the following raw materials in parts by weight: 30-60 parts of polyether polyol, 30-70 parts of macromolecular reactive bromine flame retardant, 0.01-0.2 parts of defoamer, 0.5-2 parts of black paste, and 0.01-0.1 parts of catalyst. Component B is formulated from the following raw materials in parts by weight: 10-30 parts isocyanate, 50-90 parts isocyanate-terminated polyether polyol prepolymer, and 0.01-0.2 parts defoamer.

2. The environmentally friendly two-component polyurethane potting compound according to claim 1, characterized in that, The polyether polyol in component A is one or more polyether polyols with a molecular weight of 400 to 3000. The defoamer in component A is an organosilicone defoamer; The black paste in component A is carbon black treated with low-viscosity polyether polyol. The catalyst in component A is an organometallic catalyst.

3. The environmentally friendly two-component polyurethane potting compound according to claim 2, characterized in that, The polyether polyol in component A is selected from one or more of castor oil, soybean oil, polypropylene glycol, polypropylene triol, ethylene glycol, ethylene triol, and polytetrahydrofuran ether polyol.

4. The environmentally friendly two-component polyurethane potting compound according to claim 1, characterized in that, The macromolecular reactive brominated flame retardant in component A has the molecular structure shown in the following formula: The macromolecular reactive brominated flame retardant in component A has a molecular weight of 1370.25 g / mol and a viscosity of 200–500 mPa·s at 25°C.

5. The environmentally friendly two-component polyurethane potting compound according to claim 1, characterized in that, The macromolecular reactive brominated flame retardant of component A is prepared by the following method: S1: Add 100 parts by mass of tetrabromobisphenol A and 50-60 parts by mass of methyltetrahydrophthalic anhydride to the reaction vessel, stir at 80-100℃ for 1-2 hours to fully dissolve tetrabromobisphenol A in methyltetrahydrophthalic anhydride, and then heat to 150-160℃ to react for 2-3 hours. S2: Add 110-120 parts by mass of monofunctional C14 alkyl glycidyl ether to a reaction vessel and react at 120-150°C for 1-2 hours to obtain a macromolecular reactive brominated flame retardant.

6. The environmentally friendly two-component polyurethane potting compound according to claim 5, characterized in that, In the method, tetrabromobisphenol A has the molecular structure shown in the following formula: In the method, methyltetrahydrophthalic anhydride has the molecular structure shown in the following formula: In the method, the C14 alkyl glycidyl ether has the molecular structure shown in the following formula:

7. The environmentally friendly two-component polyurethane potting compound according to claim 1, characterized in that, The isocyanate in component B is one or more of the following: diphenylmethane diisocyanate, isophorone diisocyanate, carbodiimide-modified MDI, toluene diisocyanate, and MDI dimer; The isocyanate-terminated polyurethane prepolymer in component B is obtained by reacting polyether diol and isocyanate. The defoamer in component B is an organosilicon defoamer.

8. The environmentally friendly two-component polyurethane potting compound according to claim 7, characterized in that, The raw material polyether diol for the isocyanate-terminated polyurethane prepolymer in component B is one or more of polypropylene glycol, polyethylene glycol, tetrahydrofuran copolydiol, and propylene oxide-ethylene oxide block copolydiol. The isocyanate used in the terminal isocyanate-based polyurethane prepolymer of component B is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, carbodiimide-modified isocyanate, toluene diisocyanate, and MDI dimer.

9. A method for preparing an environmentally friendly two-component polyurethane potting compound according to any one of claims 1 to 8, characterized in that, include: Component A and component B were prepared separately, wherein, Preparation of component A: S1: Add the prescribed amount of polyether polyol to the reactor, stir and vacuum dehydrate at 100-120℃ for 1-2 hours; S2: When the temperature is reduced to 40-60℃, add macromolecular reactive bromine flame retardant, defoamer, black paste, and catalyst and stir for 60-90 minutes to obtain component A; Preparation of component B: Add the formulated amount of terminal isocyanate polyether polyol prepolymer to the reactor, control the temperature to 25-40℃, add the other isocyanates and defoamer in the formulated amount, stir for 60-90 min, and obtain component B; The prepared component A and component B are stirred at a mass ratio of 100:20-40. After mixing evenly and removing air bubbles, an environmentally friendly two-component polyurethane potting compound is obtained.

10. The method for preparing the environmentally friendly two-component polyurethane potting compound according to claim 9, characterized in that, The preparation process of the terminal isocyanate polyether polyol prepolymer is as follows: the prescribed amount of polyether diol is added to the reaction vessel, stirred and vacuum dehydrated at 100-120°C for 1-2 hours, cooled to 50-70°C, the prescribed amount of isocyanate is added, the temperature is raised to 80-90°C, and the reaction is stirred continuously for 1-2 hours until the NCO content no longer changes and the reaction is ended. The polyether diol used in the preparation process of the terminal isocyanate polyether polyol prepolymer is 30-40 parts by mass and the isocyanate is 34-65 parts by mass.

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