Metal coordination polyurethane macromolecular catalyst and preparation method thereof

Abstract

The invention relates to a metal coordination polyurethane macromolecular catalyst and a preparation method thereof. A main chain of the catalyst is polyurethane, side groups are coordination groups and metal ions, and the metal coordination polyurethane macromolecular catalyst simultaneously contains (R1) urethane bonds or urea bonds, (R2) ether bonds or ester groups, (R3) coordination groups and (R4) metal ions. Wherein the groups R1 and R2 are located on a polyurethane main chain, and the group R3 is located on a polyurethane side group and is complexed with the group R4 through a coordinate bond; in the preparation method, carboxylic acid and acetylacetone ligands in coordination groups of metal salt are removed through reduced pressure distillation, so that the compatibility of the metal salt and matrix resin is improved. The metal coordination polyurethane macromolecular catalyst integrates toughening and catalysis functions, solves the problem of incompatibility caused by direct blending of a toughening agent and a curing agent in the prior art, is simple in process and convenient for large-scale industrial production, and has remarkable technical progress.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, and specifically relates to a metal-coordinated polyurethane macromolecular catalyst. Background Technology

[0002] Polyurethane, due to its good flexibility and high mechanical strength, is considered an ideal material for toughening brittle resins such as acrylic and epoxy resins. However, general-purpose polyurethanes have poor compatibility with the matrix resin, especially high molecular weight polyurethanes, which are prone to precipitation and sedimentation during blending, leading to macroscopic phase separation and making it difficult to achieve effective stress transfer, thus failing to achieve the expected toughening effect (ZL 202111264035.2, ZL 202311734661.2, ZL 201910378444.1, CN 120209257 A). Furthermore, to accelerate the curing rate of the matrix resin and shorten the process cycle, metal salts are usually added to the resin system to catalyze the polymerization reaction of acrylic monomers or promote the crosslinking and curing of epoxy resins. However, most metal salts (such as titanium acetylacetonate, iron acetylacetonate, zinc acetate, manganese naphthenate, and cyclohexylferrocene) are primarily inorganic salts. Their catalytic effect is poor at low concentrations, requiring higher concentrations. Furthermore, they exhibit poor compatibility with the polarity of the organic resin matrix, leading to phase separation and precipitation during storage or curing. This results in uneven local catalytic activity, incomplete curing, or structural defects, ultimately affecting the overall mechanical properties of the material (CN201180072652.0, CN201110418903.8, CN202110989645.2, CN202411459631.X). Therefore, improving the compatibility and dispersion stability of polyurethane toughening agents and metal salt catalysts in the resin matrix is ​​one of the challenges in the manufacture of brittle resin polymer materials.

[0003] Metal-coordinated polyurethanes (PCPs) form supramolecular networks with specific topological structures by coordinating metal ions with characteristic functional groups on the polyurethane molecular chains. This not only significantly improves the mechanical properties of polyurethanes but also endows them with functional properties such as self-healing, antibacterial, fluorescence response, and shape memory, attracting widespread attention in the field of advanced functional materials (Progress in Chemistry, 2021, 33: 2188-2202; Adv. Funct. Mater. 2025, 35, 2502720; Chem. Mater. 2025, 37, 4, 1609-1620; Chemical Engineering Journal, 2023, 474: 145719.). Currently, the main role of metal ions in polyurethane systems is to construct supramolecular network structures through coordination crosslinking for the preparation of high-performance solid polyurethane materials or polyurethane hydrogels. However, existing research mainly focuses on enhancing and functionalizing the bulk properties of polyurethanes, and there are no reports on the application of metal-coordinated polyurethanes in toughening epoxy or acrylic resin systems. However, if such metal-coordinated polyurethanes are directly mixed with matrix resins such as epoxy and acrylic, they often cannot be evenly dispersed due to poor solubility, making it difficult to achieve effective toughening or catalytic effects on the resin. Therefore, they have not been used in the production of acrylic or epoxy resins.

[0004] In summary, the current production processes of bulk brittle resins such as acrylic and epoxy resins commonly suffer from problems such as uneven dispersion and poor compatibility between toughening agents and catalysts (or accelerators) and the matrix resin, which seriously affect the mechanical strength and toughening effect of the resin. Developing integrated multifunctional materials that combine good compatibility, high catalytic efficiency, and significant toughening effect has important application prospects and practical value. Summary of the Invention

[0005] The purpose of this invention is to address the limitations of existing technologies by providing a metal-coordinated polyurethane macromolecular catalyst and its preparation method. This catalyst incorporates two groups: (R3) coordination groups and (R4) metal ions, based on a toughening polyurethane oligomer and a metal salt accelerator. The R3 groups can form hydrogen bonds, covalent bonds, or participate in curing with acrylic or epoxy resins, thereby integrating the toughening agent into the matrix resin and improving their compatibility. Furthermore, the R3 groups coordinate with the R4 metal ions, synergistically improving the compatibility between the metal ions and the matrix, enhancing the dispersibility and catalytic performance of the metal ions. This metal-coordinated polyurethane macromolecular catalyst differs from existing high-performance solid or gel materials of metal-coordinated polyurethanes, combining both toughening and catalytic functions. It solves the incompatibility problem caused by direct blending of toughening agents and curing agents, and features a simple process suitable for large-scale industrial production, representing a significant technological advancement.

[0006] The technical solution of this invention is as follows: A metal-coordinated polyurethane macromolecular catalyst, wherein the polyurethane backbone consists of R1 and R2 groups, and R3 groups are located on the side groups of the polyurethane and complex with R4 groups through coordination bonds. The macromolecular catalyst is a liquid oligomer with a molecular weight of 500-8000 g / mol. The molar ratio of R1:R2:R3 is 2:1:0.1-1, and the molar number of R4 metal ions accounts for 0.1%-5.0% of the total molar amount of the macromolecular catalyst.

[0007] Modifiers containing R3 groups can be directly added to a mixture of diisocyanate and diol or diamine for random copolymerization, resulting in a polyurethane with a low molecular weight of 500-5000 g / mol and a viscosity ≤1000 mPa.s. When modifiers containing R3 groups are added as chain extenders to the copolymerization of diisocyanate and diol or diamine, the resulting polyurethane has a high molecular weight of 5000-8000 g / mol and a viscosity ≤5000 mPa.s.

[0008] The R3 coordinating group is a group with metal coordination ability, selected from one or more of carboxylic acid group, phosphoric acid group, sulfonic acid group, pyridinyl group, and Schiff base; The metal ions mentioned are transition metal ions, depleted metal ions, and rare earth metal ions, selected from one or more of titanium (IV), chromium (III), iron (III or II), cobalt (II or III), nickel (II), zinc (II), yttrium (III), zirconium (III), europium (III), lanthanum (III), samarium (III), cerium (III), aluminum (III), and lead (II).

[0009] The R1 group is an urethane bond or a urea bond, obtained by reacting a diisocyanate with a diol or diamine containing an R2 group, specifically one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI). The R2 group is an ether bond or an ester group, selected from one or more of polyether diol, polyether diamine, polyester diol, polyester diamine, polycarbonate diol, and polycarbonate diamine.

[0010] The method for preparing the metal-coordinated polyurethane macromolecular catalyst includes the following steps: (1) Add the binary compound, diisocyanate, organotin and modifier to a reactor equipped with mechanical stirring and purge with nitrogen; keep the reactor temperature at 50-70 ℃ and perform bulk polymerization for 2-5 hours under mechanical stirring to obtain polyurethane containing coordination groups; add metal salt to polyurethane containing coordination groups for coordination, keep the temperature at 50-70 ℃ and continue mechanical stirring for 0.5-2 hours to obtain metal coordination polyurethane macromolecular catalyst; The binary compound is a diol or a diamine; The binary compound is one or more of polyether diol, polyether diamine, polyester diol, polyester diamine, polycarbonate diol, and polycarbonate diamine. The diisocyanate mentioned is one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI); The metal salt is a metal acetate or a metal acetylacetonate; the metal is a metal in the R4 metal ion; The organotin mentioned above is specifically stannous isooctanoate or dibutyltin dilaurate.

[0011] The molar ratio of binary compound: diisocyanate: organotin: modifier is 1:1.5-3:0.001-0.0025:1-2; the molar ratio of modifier: metal salt is 1:0.01-0.1. (2) The purified metal-coordinated polyurethane macromolecular catalyst was obtained by vacuum distillation for 0.2-5 hours at 80-150℃ and 0.01Pa-100kPa. The modifier is a compound containing two hydroxyl groups and at least one metal coordinating group, or a compound containing two amino groups and at least one metal coordinating group; specifically, it is 2,2-bis(hydroxymethyl)propionic acid, 2,2-dihydroxymethylbutyric acid, lysine, 2,3-bis(hydroxypropyl)phosphonic acid, diaminophosphonic acid, 2,3-dihydroxy-3-propanesulfonic acid, 2-[(2-aminoethyl)amino]ethanesulfonic acid, piperazine-N,N'-bis(2-hydroxypropanesulfonic acid), 2,6-diaminopyridine, 2,6-bis(1,2,3-triazol-4-hydroxy)pyridine, N,N'-bis(2,4-dihydroxybenzaldehyde)benzidine, or dimethylglyoxime.

[0012] The aforementioned metal-coordinated polyurethane macromolecular catalyst is used for the catalysis and toughening of resins. Specifically, the steps include the following: (1) Add the metal-coordinated polyurethane macromolecular catalyst and matrix resin to a reactor equipped with mechanical stirring, and mechanically stir at 25-80 °C for 0.5-1 hours to obtain a homogeneous and transparent mixed resin. The weight ratio of macromolecular catalyst to matrix resin is 5-100:100. The matrix resin is an acrylic resin or an epoxy resin. The epoxy resin is a two-component resin of glutaric anhydride and bisphenol A glycidyl ether.

[0013] (2) Heat the mixed resin and cure it in an oven at 100-180℃ for 0.5-4 hours to obtain toughened epoxy resin or acrylic resin. The resin transmittance is ≥80% and the haze is ≤5%.

[0014] The essential features of this invention are: In existing technologies, liquid low-molecular-weight polyurethane is used for toughening brittle resins, but its chemical structure differs greatly from that of the brittle resin matrix, lacking coordinating groups and exhibiting poor compatibility, thus affecting the toughening effect. High-molecular-weight polyurethane elastomers introduce metal ions to improve the mechanical strength of the polyurethane matrix or to impart self-healing, fluorescent, and antibacterial functions; however, when blended with a brittle resin matrix, these ions precipitate directly and cannot be used for toughening brittle resins.

[0015] The metal-coordinated polyurethane macromolecular catalyst of the present invention is in liquid state and contains coordinating groups and metal groups. It utilizes the metal coordination between the metal groups and the matrix resin molecules to increase the compatibility between the macromolecular catalyst and the matrix resin and improve the dispersibility of the macromolecular catalyst in the resin. At the same time, the uniformly dispersed metal ions have stronger catalytic performance and can promote the polymerization of acrylic acid or the ring-opening curing of epoxy at lower temperatures or in a shorter time.

[0016] In this invention, four groups are contained simultaneously: (R1) urethane bond or urea bond, (R2) ether bond or ester group, (R3) coordination group, and (R4) metal ion; wherein groups R1 and R2 are located in the polyurethane main chain, group R3 is located in the polyurethane side group, and group R4 is complexed through coordination bond; the catalyst is liquid with a molecular weight of 500-8000 g / mol.

[0017] This invention obtains a polyurethane macromolecular catalyst through the coordination of coordinating groups and metal ions. It has the advantages of low molecular weight (≤8000g / mol), low metal ion content (0.1%-5.0%), good compatibility, strong catalytic ability and good toughening effect. It solves the problems of easy separation of existing toughening agents and curing agents when directly blended with matrix resin and poor resin performance after curing.

[0018] This invention combines toughening and catalytic functions, solving the incompatibility problem caused by direct blending of existing toughening agents and curing agents. It has good compatibility with the matrix resin, is easy to mix, and does not cause macroscopic phase separation.

[0019] The present invention has the following beneficial effects: The metal-coordinated polyurethane macromolecular catalyst of this invention contains a coordinating group R3 and a metal ion R4, with a molecular weight of 500-8000 g / mol, significantly different from conventional polyurethane toughening agents used in existing acrylic and epoxy resin systems. Although existing metal-coordinated polyurethanes also incorporate the metal ion R4, its main function is to enhance the mechanical strength, self-healing properties, fluorescence characteristics, or antibacterial properties of the polyurethane bulk material by forming coordination bonds within the polyurethane matrix to construct a supramolecular network structure. Polyurethanes designed for such applications typically have high molecular weights (>8000 g / mol) and high metal ion content, exceeding 10% molar fraction. In contrast, the function of the metal ion R4 in this invention is fundamentally different, mainly in two aspects: First, R4 can coordinate with functional groups such as carboxyl, amino, or pyridine in acrylic or epoxy resins, playing a role in compatibilization and compatibility regulation; second, as a catalytic active center, a low content is sufficient to promote the polymerization reaction of acrylic acid or the curing process of epoxy resin, exerting a catalytic function. Therefore, the required amount of metal ions is significantly reduced, accounting for only 0.1%-5.0% of the total molar amount of the macromolecular catalyst. Due to its good compatibility and uniform dispersion, the low-content metal-coordinated polyurethane macromolecular catalyst can catalyze epoxy curing within 2.0-2.5 hours, shortening the curing time and demonstrating significant technological progress.

[0020] In the preparation method provided by this invention, the carboxylic acid and acetylacetone ligands in the coordination groups of the metal salt are small molecules with higher activity. If they remain in the system, they will interfere with the coordination of the coordination groups on the macromolecular polyurethane with the metal salt. Therefore, they are removed by vacuum distillation to fully utilize the coordination and catalytic effect of the metal-coordinated polyurethane macromolecular catalyst and improve its compatibility with the matrix resin.

[0021] The metal-coordinated polyurethane macromolecular catalyst for toughening provided by this invention, through the synergistic effect of the R3 coordinating group and the metal ion R4, can form various interactions such as hydrogen bonds, covalent bonds, and coordinate bonds between the catalyst and the matrix resin, effectively improving the interfacial compatibility between the two. Furthermore, this catalyst possesses both toughening and catalytic functions, overcoming the problems caused by poor compatibility between traditional toughening agents and catalysts, such as uneven dispersion, complex blending processes, insufficient resin mechanical strength, and limited toughening effect.

[0022] This material can replace existing products for toughening and modifying acrylic and epoxy resins, and the toughened epoxy resin has a fracture energy ≥1300 kJ / m. 2 It is suitable for preparing high-strength, high-toughness engineering resins and high-performance adhesives. The epoxy adhesive using metal-coordinated polyurethane macromolecular catalysts has an overlap shear strength >20 MPa, showing good application prospects and practical value. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The tensile curves of epoxy resins prepared in Examples 1, 1, and 2 of this invention are shown.

[0025] Figure 2 These are photographs showing the appearance of the epoxy resins prepared in Example 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0026] To facilitate understanding of the present invention, a more comprehensive description is provided below. Preferred embodiments of the invention are given below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable those skilled in the art to gain a thorough and complete understanding of the disclosure of the present invention.

[0027] Unless otherwise defined, the technical means and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for illustrative purposes only and does not limit the scope of protection of this invention.

[0028] This macromolecular catalyst is liquid with a molecular weight of 500-8000 g / mol. It has good compatibility with the matrix resin, is easy to mix, and does not undergo macroscopic phase separation.

[0029] When the metal-coordinated polyurethane macromolecular catalyst and the acrylic resin are miscible, they exhibit good compatibility with no macroscopic phase separation. Furthermore, the transmittance of the miscible resin is ≥80%, and the haze is ≤5%, preferably ≥90%, with a haze ≤2%.

[0030] When the metal-coordinated polyurethane macromolecular catalyst and the epoxy resin are miscible, the two have good compatibility and no macroscopic phase separation. After miscibility, the transmittance of the resin is ≥80% and the haze is ≤5%. Preferably, the transmittance of the resin is ≥90% and the haze is ≤2%.

[0031] Example 1: (1) 20 g (0.02 mol) polyethylene glycol (one of polyether glycols), 10 g (0.06 mol) hexamethylene diisocyanate, 3 mg (0.05 mmol) dibutyltin dilaurate and 5.22 g (0.04 mol) 2,2-bis(hydroxymethyl)propionic acid were added to a reactor equipped with mechanical stirring, nitrogen gas was introduced, the reactor temperature was maintained at 50 °C, bulk polymerization was carried out, mechanical stirring was performed for 2 hours, and the reaction was stopped when the viscosity reached 4000 mPa·s to obtain polyurethane containing coordination groups; then the reactor temperature was raised to 70 °C, 0.79 g (0.003 mol) titanium acetylacetone was added, and mechanical stirring was continued for 2 hours to obtain titanium-coordinated polyurethane macromolecular catalyst; (2) The acetylacetone coordination group was removed by vacuum distillation for 1 hour at 80℃ and 100kPa to obtain a purified titanium-coordinated polyurethane macromolecular catalyst with a molecular weight of 5000 g / mol and titanium accounting for 2.4% (0.003 mol) of the total molar amount of the macromolecular catalyst. Here, the molar amount of the macromolecular catalyst is the sum of the molar amounts of the binary compound, diisocyanate, organotin, metal salt and modifier.

[0032] In this process, vacuum distillation removes small molecule ligands (such as acetylacetone ligands) to prevent the more reactive acetic acid and acetylacetone ligands from remaining in the system and interfering with the coordination of ligands on macromolecular polyurethane with metal salts.

[0033] (3) 10 g (0.002 mol) of polyurethane macromolecular catalyst and epoxy resin matrix resin (containing 50 g (0.44 mol) glutaric anhydride and 100 g (1.08 mol) bisphenol A glycidyl ether) were added to a reactor equipped with mechanical stirring. The reactor temperature was kept at 70 °C and stirred for 0.5 hours to obtain a mixed resin. (4) The mixed resin was heated and cured in an oven at 120 ℃ for 30 minutes and then cured at 175 ℃ for 2 hours to obtain the toughened epoxy resin. The resin had a light transmittance of 90% and a haze of 2%.

[0034] The tensile strength of toughened epoxy resin is as follows Figure 1 As shown, compared with Comparative Example 1 (metal salt directly blended with epoxy resin matrix) and Comparative Example 2 (using commercially available polyurethane toughening agent blended with epoxy resin matrix), the epoxy resin prepared in this example has an elongation at break exceeding 6% and a fracture energy reaching 1704 kJ / m. 3 This indicates that the titanium-coordinated polyurethane macromolecular catalyst has a significant toughening effect.

[0035] Photos of the toughened epoxy resin as shown Figure 2 As shown in Comparative Example 1 (direct blending of metal salt with epoxy resin matrix), the direct blending of metal salt resulted in incomplete dispersion, leading to the appearance of obvious "pockmarked" aggregates. Compared to Comparative Example 1, the epoxy resin prepared in this example exhibits uniform color, high transparency, and no macroscopic phase separation, indicating that the titanium-coordinated polyurethane macromolecular catalyst has better compatibility with the matrix resin. This good dispersibility and compatibility are also the structural origin for achieving toughening of the matrix resin.

[0036] The shear strength of stainless steel tested by toughened epoxy resin according to GB / T 7124-2008 Adhesives—Determination of tensile shear strength (rigid material to rigid material) is shown in Table 1.

[0037] Example 2: (1) 15 g (0.015 mol) of polypropylene glycol, 5.75 g (0.023 mol) of diphenylmethane diisocyanate, 8.15 g (0.023 mol) of piperazine-N,N'-bis(2-hydroxypropanesulfonic acid), and 6 mg (0.015 mmol) of stannous isooctanoate were added to a reactor equipped with mechanical stirring. Nitrogen gas was introduced and the reactor temperature was maintained at 55 °C. Bulk polymerization was carried out and mechanical stirring was performed for 2 hours. The reactor temperature was raised to 70 °C, and 0.0235 g (0.0001 mol) of europium acetate was added. Mechanical stirring was continued for 2 hours to obtain a titanium-coordinated polyurethane macromolecular catalyst. (2) The acetic acid coordination groups were removed by vacuum distillation for 2 hours at 100 °C and 80 kPa to obtain a purified europium-coordinated polyurethane macromolecular catalyst with a concentration of 3000 g / mol. Europium accounted for 0.17% (0.0001 mol) of the total molar amount of the macromolecular catalyst. (3) Add 10 g (0.003 mol) of polyurethane macromolecular catalyst and epoxy resin matrix (containing 50 g (0.44 mol) glutaric anhydride and 100 g (1.08 mol) bisphenol A glycidyl ether) to a reactor equipped with mechanical stirring, keep the reactor temperature at 60 ℃, and stir for 1 hour to obtain mixed resin; (4) The mixed resin was heated and cured in an oven at 120 ℃ for 30 minutes and then cured at 175 ℃ for 1.5 hours to obtain the toughened epoxy resin. The resin had a light transmittance of 88% and a haze of 3%.

[0038] The tensile strength of the toughened epoxy resin is 57 MPa. The shear strength of the stainless steel tested by the toughened epoxy resin according to the national standard GB / T 7124-2008, "Adhesives: Determination of tensile shear strength (rigid material to rigid material)", is shown in Table 1.

[0039] Example 3: (1) 15 g (0.015 mol) of polyethylene glycol diamine, 10 g (0.040 mol) of dicyclohexylmethane diisocyanate, 6.15 g (0.025 mol) of 2,3-di(hydroxypropyl)phosphoric acid, and 6 mg (0.015 mmol) of stannous isooctanoate were added to a reactor equipped with mechanical stirring and nitrogen gas was introduced. The reactor temperature was maintained at 55 °C for bulk polymerization and mechanically stirred for 2 hours to obtain polyurethane. The reactor temperature was raised to 70 °C and 0.736 g (0.004 mol) of zinc acetate was added. Mechanical stirring was continued for 2 hours to obtain a zinc-coordinated polyurethane macromolecular catalyst. (2) The acetic acid coordination groups were removed by vacuum distillation for 3 hours at 100 °C and 80 kPa to obtain a purified zinc-coordinated polyurethane macromolecular catalyst with a molecular weight of 4000 g / mol and zinc accounting for 5.0% (0.004 mol) of the total molar amount of the macromolecular catalyst. (3) 10 g (0.0025 mol) of polyurethane macromolecular catalyst and epoxy resin matrix (containing 50 g (0.44 mol) glutaric anhydride and 100 g (1.08 mol) bisphenol A glycidyl ether) were added to a reactor equipped with mechanical stirring. The reactor temperature was kept at 65 °C and stirred for 1.5 hours to obtain a mixed resin. (4) The mixed resin was heated and cured in an oven at 130 ℃ for 30 minutes and then cured at 175 ℃ for 2 hours to obtain the toughened epoxy resin. The resin had a light transmittance of 95% and a haze of 1.5%.

[0040] The tensile strength of the toughened epoxy resin is 43 MPa. The shear strength of the stainless steel tested by the toughened epoxy resin according to the national standard GB / T 7124-2008, "Adhesives: Determination of tensile shear strength (rigid material to rigid material)", is shown in Table 1.

[0041] Example 4: (1) 15 g (0.015 mol) polycaprolactone diamine, 10 g (0.045 mol) isophorone diisocyanate, and 6 mg (0.015 mmol) stannous isooctanoate were added to a reactor equipped with mechanical stirring and nitrogen was introduced. The reactor temperature was maintained at 55 °C for bulk polymerization and mechanical stirring was carried out for 2 hours. Then, 7 g (0.03 mol) 2,6-bis(1,2,3-triazole-4-hydroxy)pyridine was added and mechanical stirring was continued for 2 hours. The reactor temperature was then raised to 70 °C and 0.0188 g (0.073 mol) cobalt acetylacetone was added and mechanical stirring was continued for 2 hours to obtain a cobalt-coordinated polyurethane macromolecular catalyst. (2) The acetylacetone coordination group was removed by vacuum distillation for 2 hours at 80 °C and 90 kPa to obtain a purified cobalt-coordinated polyurethane macromolecular catalyst with a molecular weight of 8000 g / mol and cobalt accounting for 4.4% (0.073 mol) of the total molar amount of the macromolecular catalyst. (3) 10 g (0.0013 mol) of polyurethane macromolecular catalyst and epoxy resin matrix (containing 50 g (0.44 mol) glutaric anhydride and 100 g (1.08 mol) bisphenol A glycidyl ether) were added to a reactor equipped with mechanical stirring. The reactor temperature was kept at 50 °C and stirred for 2 h to obtain a mixed resin. (4) The mixed resin was heated and cured in an oven at 130 ℃ for 20 minutes and then cured at 175 ℃ for 2.5 hours to obtain the toughened epoxy resin. The resin had a light transmittance of 82% and a haze of 5%.

[0042] The tensile strength of the toughened epoxy resin is 58 MPa. The shear strength of the stainless steel tested by the toughened epoxy resin according to the national standard GB / T 7124-2008, "Adhesives: Determination of tensile shear strength (rigid material to rigid material)", is shown in Table 1.

[0043] Example 5: (1) 15 g (0.015 mol) of polycarbonate diol, 10 g (0.044 mol) of lysine diisocyanate, and 6 mg (0.015 mmol) of stannous isooctanoate were added to a reactor equipped with mechanical stirring and nitrogen was introduced. The reactor temperature was maintained at 55 °C for bulk polymerization and mechanical stirring was carried out for 2 hours. Then, 5.8 g (0.017 mol) of N,N'-bis(2,4-dihydroxybenzaldehyde) benzidine was added and mechanical stirring was continued for 2 hours. The reactor temperature was raised to 70 °C and 0.0482 g (0.00017 mol) of yttrium acetate was added and mechanical stirring was continued for 2 hours to obtain yttrium-coordinated polyurethane macromolecular catalyst. (2) The acetic acid coordination groups were removed by vacuum distillation for 1 hour at 90 °C and 100 kPa to obtain a purified yttrium coordination polyurethane macromolecular catalyst with a molecular weight of 6000 g / mol and yttrium accounting for 0.24% (0.00017 mol) of the total molar amount of the macromolecular catalyst. (3) Add 50 g (0.0083 mol) of polyurethane macromolecular catalyst, acrylic resin matrix (containing 100 g (1.387 mol) acrylic acid, 50 g (0.431 mol) hydroxyethyl acrylate), and 5 mg (0.030 mol) azobisisobutyronitrile to a reactor equipped with mechanical stirring, maintain the reactor temperature at 25 ℃, and stir for 0.5 h to obtain a mixed resin; (4) The mixed resin was heated and cured in an oven at 50 ℃ for 2 hours to obtain toughened acrylic resin with a light transmittance of 96% and a haze of 1.0%.

[0044] The tensile strength of the toughened acrylic resin is 50 MPa, and the shear strength of the stainless steel tested by the toughened acrylic resin according to the national standard GB / T 7124-2008, "Adhesives: Determination of tensile shear strength (rigid material to rigid material)", is 15 MPa.

[0045] Example 6: (1) 15 g (0.015 mol) polycaprolactone diamine, 5 g (0.022 mol) lysine diisocyanate, 3.86 g (0.023 mol) hexamethylene diisocyanate, and 6 mg (0.015 mmol) stannous isooctanoate were added to a reactor equipped with mechanical stirring. Nitrogen gas was introduced and the reactor temperature was maintained at 55 °C for bulk polymerization. The mixture was mechanically stirred for 2 hours. Then, 3.6 g (0.023 mol) 2,3-dihydroxy-3-propanesulfonic acid was added and mechanical stirring was continued for 2 hours. The reactor temperature was raised to 70 °C and 0.224 g (0.00046 mol) zirconium acetylacetonate was added. The mixture was mechanically stirred for 2 hours to obtain a zirconium-coordinated polyurethane macromolecular catalyst.

[0046] (2) The acetylacetone coordination group was removed by vacuum distillation for 1.5 hours at 80 °C and 100 kPa to obtain a purified zirconium-coordinated polyurethane macromolecular catalyst with a molecular weight of 8000 g / mol and zirconium accounting for 0.76% (0.00046 mol) of the total molar amount of the macromolecular catalyst. (3) 30 g (0.0038) of polyurethane macromolecular catalyst, acrylic resin matrix (containing 100 g (1.387 mol) of acrylic acid and 50 g (0.431 mol) of hydroxyethyl acrylate), and 0.5 g (0.002 mol) of ethyl 2,4,6-trimethylbenzoylphosphonate were added to a reactor equipped with mechanical stirring. The reactor temperature was kept at 25 °C and stirred for 1 h to obtain a mixed resin. (4) The mixed resin was heated and cured in a 370 nm light curing oven for 10 minutes to obtain toughened acrylic resin with a light transmittance of 80% and a haze of 5%.

[0047] The tensile strength of the toughened acrylic resin is 38 MPa, and the shear strength of the stainless steel tested by the toughened acrylic resin according to the national standard GB / T 7124-2008, which specifies the determination of tensile shear strength (rigid material to rigid material), is 12 MPa.

[0048] Comparative Example 1: (1) Add 50 g (0.44 mol) glutaric anhydride, 100 g (1.08 mol) bisphenol A glycidyl ether, and 0.79 g (0.003 mol) titanium acetylacetonate to a reactor equipped with mechanical stirring, keep the reactor temperature at 70 ℃, and stir for 1 hour to obtain a mixed resin; (2) The mixed resin was heated and cured in an oven at 130 ℃ for 2 hours and then cured at 175 ℃ for 4 hours to obtain ordinary epoxy resin. The resin had a light transmittance of 88% and a haze of 6%.

[0049] The tensile strength of ordinary epoxy resin is as follows Figure 1 As shown in Table 1, the shear strength of stainless steel tested with ordinary epoxy resin according to GB / T 7124-2008 Adhesives—Determination of tensile shear strength (rigid material to rigid material) is shown in Table 1.

[0050] Comparative Example 2: (1) 10 g (0.01 mol) commercially available polyurethane toughening agent A, 50 g (0.44 mol) glutaric anhydride, 100 g (1.08 mol) bisphenol A glycidyl ether, and 1 g (0.004 mol) titanium acetylacetonate were added to a reactor equipped with a mechanical stirrer. The reactor temperature was maintained at 80 °C and stirred for 0.5 hours to obtain a mixed resin. (2) The mixed resin was heated and cured in an oven at 130 ℃ for 30 minutes and then cured at 175 ℃ for 2 hours to obtain epoxy resin modified with commercially available polyurethane toughening agent A. The resin had a light transmittance of 88% and a haze of 3%.

[0051] The tensile strength of epoxy resin modified with commercially available polyurethane toughening agent A is as follows: Figure 1 As shown in Table 1, the shear strength of stainless steel modified with commercially available polyurethane toughening agent A was tested according to GB / T 7124-2008 Adhesives—Determination of tensile shear strength (rigid material to rigid material).

[0052] Comparative Example 3: (1) 10 g (0.015 mol) commercially available polyurethane toughening agent B, 50 g (0.44 mol) glutaric anhydride, 100 g (1.08 mol) bisphenol A glycidyl ether, and 0.79 g (0.003 mol) titanium acetylacetonate were added to a reactor equipped with a mechanical stirrer. The reactor temperature was maintained at 60 °C and stirred for 2 hours to obtain a mixed resin. (2) The mixed resin was heated and cured in an oven at 130 ℃ for 30 minutes and then cured at 175 ℃ for 2 hours to obtain epoxy resin modified with commercially available polyurethane toughening agent B. The resin had a light transmittance of 88% and a haze of 3%.

[0053] The tensile strength of epoxy resin modified with commercially available polyurethane toughening agent B is 35 MPa. The shear strength of stainless steel modified with commercially available polyurethane toughening agent B, according to GB / T 7124-2008 Adhesives—Determination of tensile shear strength (rigid material to rigid material) is shown in Table 1.

[0054] Based on Examples 1-6 and Comparative Examples 1-3, it can be seen that the metal-coordinated polyurethane macromolecular catalyst proposed in this invention has good compatibility with acrylic resin and epoxy resin. Figure 2 The addition of metal coordination ions increases the compatibility between the toughening agent and the matrix resin, improving upon the technical shortcomings of poor compatibility between inorganic metal salt catalysts and ordinary toughening agents and the matrix resin. Furthermore, due to their good compatibility, metal-coordinated polyurethane macromolecular catalysts can achieve the curing of epoxy and acrylic resins at relatively low metal ion contents, significantly accelerating the polymerization of acrylic acid and the curing rate of epoxy resin (Table 1). Figure 1 The tensile test results in Table 1 also show that the epoxy resin toughened with the metal-coordinated polyurethane macromolecular catalyst has lower strength than the untoughened resin, but significantly increased toughness, and both strength and toughness are significantly improved compared to epoxy resin with commercially available toughening agents. The lap shear strength of the toughened epoxy resin used as a metal adhesive is >20 MPa, while the lap shear strength of ordinary epoxy resin and epoxy resin modified with commercially available toughening agents is <20 MPa. Therefore, compared with existing technologies, this invention can significantly improve the compatibility of toughening agents and catalysts with the matrix resin, and significantly improve the toughness of the matrix resin, increasing its metal bonding strength. It provides a new technical means for the toughening modification of brittle resins, possessing outstanding substantive features and significant progress. The metal-coordinated macromolecular catalyst proposed in this invention, after being mixed with acrylic or epoxy resin, has great application value in the fields of adhesives, coatings, and paints.

[0055] Table 1. Strength of different epoxy resins and lap shear strength of bonded stainless steel

[0056] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The embodiments described above only illustrate several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0057] Matters not covered in this invention are common knowledge.

Claims

1. A metal-coordinated polyurethane macromolecular catalyst characterized in that, In the catalyst, the polyurethane main chain is R1 and R2 groups, R3 groups are located in the polyurethane side groups, and are complexed with R4 groups through coordination bonds; The molar ratio of R1:R2:R3 is 2:1:0.1-1, and the molar number of R4 metal ions accounts for 0.1%-5.0% of the total molar number of the macromolecular catalyst; The R1 group is an urethane bond or a urea bond, and the R2 group is an ether bond or an ester group; The R3 group is one or more of a carboxylic acid group, a phosphoric acid group, a sulfonic acid group, a pyridine group, and a Schiff base group; The R4 group is a metal ion, and the metal ion is one or more of a transition metal ion, a poor metal ion, and a rare earth metal ion; The catalyst is a liquid oligomer, the molecular weight is 500-8000 g / mol, and the viscosity is ≤5000 mPa.s.

2. The metal-coordinated polyurethane macromolecular catalyst of claim 1, wherein, The metal ion is one or more of titanium (IV), chromium (III), iron (III or II), cobalt (II or III), nickel (II), zinc (II), yttrium (III), zirconium (III), europium (III), lanthanum (III), samarium (III), cerium (III), aluminum (III), and lead (II).

3. The metal-coordinated polyurethane macromolecular catalyst of claim 1, wherein, The R1 group is one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

4. The metal-coordinated polyurethane macromolecular catalyst of claim 1, wherein, The R2 group is one or more of a polyether diol, a polyether diamine, a polyester diol, a polyester diamine, a polycarbonate diol, and a polycarbonate diamine.

5. The preparation method of the metal-coordinated polyurethane macromolecular catalyst as described in claim 1, characterized in that, The method comprises the following steps: (1) adding a binary compound, a diisocyanate, an organic tin, and a modifier into a reactor provided with mechanical stirring, and filling nitrogen; keeping the temperature of the reactor at 50-70 ℃, and bulk polymerizing for 2-5 hours under mechanical stirring to obtain a polyurethane containing a coordination group; adding a metal salt into the polyurethane containing the coordination group for coordination, and keeping the temperature at 50-70 ℃ and continuing mechanical stirring for 0.5-2 hours to obtain a metal-coordinated polyurethane macromolecular catalyst; wherein the molar ratio of the binary compound:diisocyanate:organic tin:modifier is 1:1.5-3:0.001-0.0025:1-2; and the molar ratio of the modifier:metal salt is 1:0.01-0.1; The binary compound is a dihydric alcohol or a diamine; The modifier is a compound containing two hydroxyl groups and at least one metal coordination group, or a compound containing two amine groups and at least one metal coordination group; The metal salt is a metal acetate or a metal acetylacetone salt; and the metal is the metal in the R4 group; (2) under the conditions of 80-150 ℃ and 0.01 Pa-100 kPa, vacuum distillation is performed for 0.2-5 hours to obtain a purified metal-coordinated polyurethane macromolecular catalyst.

6. The preparation method of the metal-coordinated polyurethane macromolecular catalyst as described in claim 5, characterized in that, The modifier is 2,2-bis(hydroxymethyl)propionic acid, 2,2-dihydroxymethyl butyric acid, lysine, 2,3-bis(hydroxypropyl)phosphoric acid, diaminophosphoric acid, 2,3-dihydroxy-3-propanesulfonic acid, 2-[(2-aminoethyl)amino]ethanesulfonic acid, piperazine-N,N'-bis(2-hydroxypropane sulfonic acid), 2,6-diaminopyridine, 2,6-bis(1,2,3-triazole-4-hydroxy)pyridine, N,N'-bis(2,4-dihydroxybenzaldehyde) benzidine or butanedione oxime, and the organic tin is isooctanoic acid stannous or dibutyl tin dilaurate.

7. The preparation method of the metal-coordinated polyurethane macromolecular catalyst according to claim 5, characterized in that, The binary compound is one or more of polyether glycol, polyether diamine, polyester glycol, polyester diamine, polycarbonate glycol, and polycarbonate diamine. The diisocyanate is one or more of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

8. Use of a metal-coordinated polyurethane macromolecule catalyst according to claim 1, characterized in that, Catalysis and toughening for resin.

9. Use of a metal-coordinated polyurethane macromolecule catalyst according to claim 1, characterized in that, The method comprises the following steps: (1) adding a metal coordination polyurethane macromolecular catalyst and a base resin into a reactor equipped with mechanical stirring, and stirring mechanically at 25-80 ℃ for 0.5-1 hour to obtain a homogeneous transparent mixed resin; The weight ratio of the macromolecular catalyst to the base resin is 5-100:100; The base resin is an acrylic resin or an epoxy resin; (2) heating and curing the mixed resin in an oven at 100-180 ℃ for 0.5-4 hours to obtain a toughened epoxy resin or acrylic resin, and the resin has a transmittance of ≥80% and a haze of ≤5%.

10. Use of a metal-coordinated polyurethane macromolecule catalyst according to claim 9, characterized in that, The epoxy resin is glutaric anhydride and bisphenol A glycidyl ether two-component resin.

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