A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant

Abstract

A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant comprises, by weight, 65-90 parts of an isocyanate-terminated liquid polybutadiene resin and 10-35 parts of a modified aromatic amine curing agent. The isocyanate-terminated liquid polybutadiene resin is prepared by reacting hydroxyl-terminated polybutadiene rubber with an aliphatic diisocyanate in a molar ratio of 1:2.0-2.5, and the hydroxyl-terminated liquid polybutadiene has a number-average molecular weight of 1200-3000 and a hydroxyl value of 1.6-0.7 mmol / g. The modified aromatic amine curing agent is obtained by reacting aminobenzylamine, an acrylate monomer, and acrylonitrile in a molar ratio of 2:1:2, wherein the acrylate monomer is one or a mixture of two or more of 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene) diacrylate. The prepared polybutadiene polyurethane urea has a microphase separation aggregation structure and has good adhesion properties to both polar and low-polar materials.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and in particular relates to a modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant. Background Art

[0002] Polyurethane is generally prepared by the reaction of polyether / polyester polyols, isocyanates and chain extenders such as small molecule polyols. When an amine-containing (or amino) curing agent replaces the polyol, a polyurea structure is formed. Polyurethane and polyurea have excellent comprehensive performance, diverse product forms and simple processing technology, and have become an important polymer adhesive sealing material. When low-polarity polybutadiene is used as the main resin, the prepared polybutadiene polyurethane or polyurea has excellent water resistance and low-temperature resistance, and can be used as special adhesives and sealants. In actual use, according to the polarity of the bonded sealing interface and the operating conditions, low-polarity polybutadiene polyurethane or strong-polarity polyether / polyester polyurethane (or polyurea) can be selected for application.

[0003] Common aromatic amine curing agents for polyurethanes and polyureas include 3,3'-dichloro-4,4'-diaminophenylmethane (MOCA) and 3,5-dimethylthiotoluenediamine (E-300). These aromatic curing agents, due to the presence of rigid benzene rings and the symmetrical molecular structures of some aromatic diamines, can impart excellent mechanical properties, modulus, solvent resistance, wear resistance, and heat resistance to polyurethanes and polyureas. However, aromatic amine curing agents like MOCA and E-300 have relatively low molecular weights, resulting in significant mismatches with prepolymers such as isocyanate-terminated polyethers, leading to inconvenient construction processes. Furthermore, due to the low molecular weight and limited number of strongly polar groups in these curing agents, the polyurethane system has a high crosslink density, making it difficult to form a multiphase aggregate structure and to simultaneously bond materials of varying polarity.

[0004] In the prior art, some polyurethanes use multiple raw materials, such as polybutadiene and polyether, to regulate the polarity and bonding properties of the polyurethane material. For example, CN110437420A discloses a modified polyurethane glue for plastic track waterproofing, comprising 100 parts of polyether polyol, 10-20 parts of hydroxyl-terminated polybutadiene, 10-20 parts of hydroxyl-terminated silicone, 57.2-66.7 parts of polyisocyanate, 53-62 parts of plasticizer, 0.1-0.3 parts of catalyst, and 0.3-0.5 parts of leveling agent. The polyether is modified with a small amount of hydroxyl-terminated polybutadiene and silicone to adjust the polarity of the polyether polyurethane to that of cement and asphalt, thereby improving the bond strength between the waterproofing layer and the base layer, and enhancing the aging resistance and water resistance of the polyurethane glue. However, the prior art still has poor bonding performance when simultaneously bonding and sealing interfaces with different polarities, especially when simultaneously bonding polar materials and low-polarity materials, such as when bonding polar steel and low-polarity styrene-butadiene rubber. Summary of the Invention

[0005] To solve the technical problem of simultaneously bonding two different types of materials, polar and low-polarity, and optimize the construction process such as the mixing ratio, the present invention provides a modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant. The adhesive sealant is composed, by weight, of 65-90 parts of an isocyanate-terminated liquid polybutadiene resin and 10-35 parts of a modified aromatic amine curing agent. After the above components are evenly mixed, they are cured at 20-80°C for 1-5 days to obtain the polybutadiene polyurethane urea. The polybutadiene polyurethane urea has good bonding properties to both polar and low-polarity materials.

[0006] The isocyanate-terminated polybutadiene resin is prepared by reacting a hydroxyl-terminated liquid polybutadiene resin with an aliphatic diisocyanate at a molar ratio of 1:2-2.5 at 60±10°C for 3-5 hours, wherein the hydroxyl-terminated liquid polybutadiene has a number average molecular weight of 1200-3000 and a hydroxyl value of 1.6-0.70 mmol / g, and is vacuum dehydrated at 110±10°C for 2 hours or more before use.

[0007] The modified aromatic amine curing agent is a liquid obtained by reacting aminobenzylamine, an acrylate monomer, and acrylonitrile in a molar ratio of 2:1:2. The aminobenzylamine is one or a mixture of two or more of 2-aminobenzylamine, 3-aminobenzylamine, and 4-aminobenzylamine; and the acrylate monomer is one or a mixture of two or more of 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene) diacrylate.

[0008] The modified aromatic amine curing agent is prepared by mixing 2 moles of aminobenzylamine with 1 mole of acrylate monomer under nitrogen protection, reacting the mixture at room temperature for 1-2 hours, and then heating the mixture at 60-80°C for 1-2 hours; then adding 2 moles of acrylonitrile to the mixture, stirring the mixture at 60-80°C for 1-2 hours, and obtaining the modified aromatic amine curing agent.

[0009] Principle of the invention:

[0010] (1) Synthesis principle: The difference in reactivity between the aniline and aliphatic amine functional groups contained in aminobenzylamine is utilized: the active hydrogen of aliphatic amine can undergo addition reaction with double bonds, while aniline has low reactivity and cannot participate in double bond addition reaction, but has high reactivity with isocyanate. Therefore, the aliphatic amine functional group in aminobenzylamine is first used to undergo addition chain extension reaction with acrylate monomer and acrylonitrile, introducing a variety of strong polar groups such as ester bond, nitrile group, tertiary amine, etc., while retaining the aniline functional group, thereby obtaining a modified aromatic amine curing agent; the aniline functional group in the modified aromatic amine is then used to react with diisocyanate-terminated polybutadiene resin, and finally a polybutadiene polyurethane urea adhesive sealant is prepared.

[0011] The structural diagram and synthetic route of the modified aromatic amine curing agent are as follows:

[0012]

[0013] Modified aromatic amine curing agent

[0014] The structural diagram and synthetic route of modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant are as follows:

[0015]

[0016] A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant

[0017] (2) Adhesion and sealing principle: Modified aromatic amines containing multiple strong polar groups such as ester bonds, nitrile groups, and tertiary amines react with low-polarity liquid polybutadiene resins to prepare multi-phase structured polybutadiene polyurethane urea containing different polar aggregation states, which has the ability to simultaneously bond and seal materials with different polarities.

[0018] The present invention has the following beneficial effects: Isocyanate-terminated polybutadiene consists of low-polarity segments, while modified aromatic amine curing agents contain multiple highly polar groups, such as ester bonds, nitrile groups, and tertiary amines. These two groups are inherently incompatible. However, during preparation, the high reactivity between the isocyanate and aniline functional groups in the modified aromatic amine, as well as the autocatalytic effect of the tertiary amine, allows the low-polarity polybutadiene of a specific molecular weight to react rapidly and compatibilize with the highly polar modified aromatic amine, forming an aggregated state with a pronounced micrometer-scale phase separation structure. The polybutadiene segments in the prepared polybutadiene polyurethaneurea serve as the matrix, facilitating adhesion to low-polarity interfaces; while the aromatic amine segments serve as the dispersed phase, facilitating adhesion to polar interfaces. This achieves simultaneous adhesion and sealing of both low-polarity and polar materials, resulting in excellent bonding performance. Furthermore, the molecular weight of the modified aromatic amine is more than double that of commercial aromatic amine curing agents such as MOCA and E-300, eliminating the need for a large disparity in the curing agent to isocyanate-terminated prepolymer ratio and improving processability. DETAILED DESCRIPTION

[0019] Example 1

[0020] A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant is composed, by weight, of 80 parts of an isocyanate-terminated liquid polybutadiene resin and 20 parts of a modified aromatic amine curing agent. The components are uniformly mixed and cured at 20° C. for 5 days to obtain the polybutadiene polyurethane urea.

[0021] The isocyanate-terminated liquid polybutadiene resin is prepared by reacting a hydroxyl-terminated liquid polybutadiene resin with isophorone diisocyanate at a molar ratio of 1:2 at 60° C. for 5 hours, wherein the hydroxyl value of the hydroxyl-terminated liquid polybutadiene resin is 1.45 mmol / g.

[0022] The modified aromatic amine curing agent is obtained by reacting 3-aminobenzylamine, 1,6-hexanediol diacrylate, and acrylonitrile in a molar ratio of 2:1:2. The preparation steps are as follows: Under nitrogen protection, 2 moles of 3-aminobenzylamine and 1 mole of 1,6-hexanediol diacrylate are mixed, reacted at room temperature for 2 hours, and then heated at 80°C for another 2 hours; then, 2 moles of acrylonitrile are added to the mixture, and the mixture is stirred and reacted at 60°C for 2 hours to obtain the modified aromatic amine curing agent.

[0023] Example 2

[0024] A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant is composed, by weight, of 84 parts of an isocyanate-terminated liquid polybutadiene resin and 16 parts of a modified aromatic amine curing agent. The components are uniformly mixed and cured at 80°C for one day to obtain the polybutadiene polyurethane urea.

[0025] The isocyanate-terminated liquid polybutadiene resin is prepared by reacting a hydroxyl-terminated liquid polybutadiene resin with hexamethylene diisocyanate at a molar ratio of 1:2.1 at 60° C. for 5 hours, wherein the hydroxyl value of the hydroxyl-terminated liquid polybutadiene resin is 0.78 mmol / g.

[0026] The modified aromatic amine curing agent is obtained by reacting 1.6 moles of 3-aminobenzylamine, 0.4 moles of 2-aminobenzylamine, 1 mole of neopentyl glycol diacrylate, and 2 moles of acrylonitrile. The preparation steps are as follows: Under nitrogen protection, 2 moles of aminobenzylamine and 1 mole of neopentyl glycol diacrylate are mixed, reacted at room temperature for 2 hours, and then heated at 70°C for another 2 hours. Then, 2 moles of acrylonitrile are added to the mixture, and the mixture is stirred and reacted at 60°C for 2 hours to obtain the modified aromatic amine curing agent.

[0027] Example 3

[0028] A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant is composed, by weight, of 75 parts of an isocyanate-terminated liquid polybutadiene resin and 23 parts of a modified aromatic amine curing agent. The components are uniformly mixed and cured at 60° C. for 2 days to obtain the polybutadiene polyurethane urea.

[0029] The isocyanate-terminated liquid polybutadiene resin is prepared by reacting a hydroxyl-terminated liquid polybutadiene resin with isophorone diisocyanate at a molar ratio of 1:2.2 at 60° C. for 5 hours, wherein the hydroxyl value of the hydroxyl-terminated liquid polybutadiene resin is 1.45 mmol / g.

[0030] The modified aromatic amine curing agent is obtained by reacting 3-aminobenzylamine, (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene)diacrylate, and acrylonitrile in a molar ratio of 2:1:2. The preparation steps are as follows: under nitrogen protection, 2 moles of 3-aminobenzylamine and 1 mole of (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene)diacrylate are mixed, reacted at room temperature for 2 hours, and then heated at 80°C for another 2 hours; then, 2 moles of acrylonitrile are added to the mixture, and the mixture is stirred and reacted at 60°C for 2 hours to obtain a modified aromatic amine curing agent.

[0031] Table 1 Shear bond strength of polybutadiene polyurethane urea cured with commercial aromatic amine (MPa)

[0032]

[0033] The specific implementation examples described in this invention are only preferred implementation examples of the invention and are not intended to limit the scope of implementation of the invention. That is, all equivalent changes and modifications made within the scope of the patent application of this invention should be considered as the technical scope of this invention.

Claims

1. A modified aromatic amine-cured polybutadiene polyurethane urea adhesive sealant, comprising 65-90 parts by weight of an isocyanate-terminated liquid polybutadiene resin, characterized in that The invention also comprises 10-35 parts of a modified aromatic amine curing agent; wherein the isocyanate-terminated liquid polybutadiene resin is prepared by reacting hydroxyl-terminated polybutadiene rubber with an aliphatic diisocyanate in a molar ratio of 1:2.0-2.5, and the number average molecular weight of the hydroxyl-terminated liquid polybutadiene is 1200-3000, and the hydroxyl value is 1.6-0.7 mmol / g; and the modified aromatic amine curing agent is prepared by reacting aminobenzylamine, an acrylate monomer, and acrylonitrile in a molar ratio of 2:1:2, wherein the aminobenzylamine is a mixture of one or two or more of 2-aminobenzylamine, 3-aminobenzylamine, and 4-aminobenzylamine, and the acrylate monomer is a mixture of one or two or more of 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene) diacrylate.

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