Imine heterocyclic compound, chain extender, cross-linking agent, polyurethane adhesive and product

Abstract

The invention discloses an imine heterocyclic compound, a chain extender, a cross-linking agent, a polyurethane adhesive and a product, and belongs to the field of polyurethane adhesives, and the general formula of the chemical structure of the imine heterocyclic compound is as shown in the formula I. The imine heterocyclic compound provided by the invention has a polyhydroxy group, an imine structure, a five-membered heterocyclic aromatic structure connected with the imine structure and the like, so that the stability of the compound is greatly enhanced, and the compound is endowed with multiple characteristics of crosslinking, chain extension and the like. When the polyurethane adhesive is applied to preparation of the polyurethane adhesive, the comprehensive mechanical properties such as shear strength and tensile strength of the polyurethane adhesive can be remarkably improved, and the application prospect is wide.

Description

Technical Field

[0001] This application belongs to the field of polyurethane adhesives, specifically relating to an imine heterocyclic compound, a chain extender, a crosslinking agent, a polyurethane adhesive, and an article thereof. Background Technology

[0002] Polyurethane adhesives are high-performance adhesives with polyurethane as the main component. They form cross-linked network polymers through the reaction of isocyanates with polyols or polyamines. Because the formed urethane or urethane contains a large number of hydrogen bonds, they have high strength and high adhesion, and are widely used.

[0003] Currently, polyurethane adhesives are mainly used in industrial, automotive, and semiconductor electronics fields, and are particularly suitable for bonding different materials, such as metal-composite materials. However, polyurethane adhesives are still weaker than epoxy adhesives in terms of shear strength and tensile strength, thus limiting their further widespread application. Summary of the Invention

[0004] This application aims to at least partially solve one of the technical problems in the related art. Therefore, the purpose of this application is to provide an imine heterocyclic compound, a chain extender, a crosslinking agent, a polyurethane adhesive, and an article thereof. The imine heterocyclic compound of this application has multiple hydroxyl groups, an imine structure, and a five-membered heterocyclic aromatic structure linked to the imine structure, which not only significantly enhances the stability of the compound but also endows it with multiple properties such as crosslinking and chain extension. When applied to the preparation of polyurethane adhesives, it can significantly improve the comprehensive mechanical properties of polyurethane adhesives, such as shear strength and tensile strength, and has broad application prospects.

[0005] The first aspect of this application discloses an imine heterocyclic compound. According to embodiments of this application, the general chemical structural formula of the imine heterocyclic compound is shown in Formula I; Equation I: ; R is a C1~C10 alkyl, C5~C10 cycloalkyl, aryl or heterocyclic group; R1 and R2 are each independently an alkyl group having 0 to 3 carbon atoms; X is oxygen, sulfur, or nitrogen; n is any natural number from 1 to 3, such as 1, 2, and 3.

[0006] The imine heterocyclic compounds of the above embodiments of this application possess multiple hydroxyl groups, an imine structure, and a five-membered heterocyclic aromatic structure linked to the imine structure. This not only significantly enhances the stability of the compounds but also endows them with multiple properties such as crosslinking and chain extension. When applied to the preparation of polyurethane adhesives, they can significantly improve the comprehensive mechanical properties of polyurethane adhesives, such as shear strength and tensile strength, and have broad application prospects.

[0007] In addition, the imine heterocyclic compounds according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, the imine heterocyclic compound includes at least one of a first furanimide compound, a second furanimide compound, a third furanimide compound, a fourth furanimide compound, and a fifth furanimide compound; The first furanimine compound satisfies the following conditions: 1) R is a C1~C10 alkyl or C5~C10 cycloalkyl; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The second furanimine compound satisfies the following conditions: 1) R is hydrogen or a phenyl group substituted with at least one C1-C10 alkyl group; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The third furanimide compound satisfies the following conditions: 1) R is hydrogen or a phenyl substituted with at least one C1-C10 alkyl group; 2) R1 and R2 are each independently C1-C3 straight-chain alkyl groups; 3) X is oxygen; 4) n is 1; The fourth furanimine compound satisfies the following conditions: 1) R is a phenyl group substituted with at least one C1~C10 alkyl group and substituted with the structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The fifth furanimine compound satisfies the following conditions: 1) R is a triazine cyclogroup substituted with at least one structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; Formula II: .

[0008] In some embodiments of this application, the chemical formula of the first furanimide compound is as follows: R is methyl, ethyl, or propyl; Alternatively, the chemical formula of the second furanimide compound is shown below: R3, R4, and R5 are each independently hydrogen or C1-C10 alkyl groups; Alternatively, the chemical formula of the third furanimide compound is shown below: ; R1 and R2 are both methylene, and R3, R4 and R5 are each independently hydrogen or C1~C10 alkyl; And / or, the chemical formula of the fourth furanimide compound is shown below: R3, R4, and R5 are each independently hydrogen or C1-C10 alkyl groups; Alternatively, the chemical formula of the fifth furanimide compound is shown below; .

[0009] A second aspect of this application discloses a chain extender. According to embodiments of this application, the chain extender comprises the imine heterocyclic compound described in the first aspect. Therefore, this chain extender exhibits excellent stability and, when applied to the preparation of polyurethane adhesives, can significantly improve the overall mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0010] A third aspect of this application discloses a crosslinking agent. According to embodiments of this application, the crosslinking agent comprises the imine heterocyclic compound described in the first aspect. Therefore, this crosslinking agent exhibits excellent stability and, when applied to the preparation of polyurethane adhesives, can significantly improve the overall mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0011] A fourth aspect of this application discloses a polyurethane adhesive. According to embodiments of this application, the polyurethane adhesive comprises the imine heterocyclic compound described in the first aspect. Consequently, the overall mechanical properties of this polyurethane adhesive, such as shear strength and tensile strength, are significantly improved.

[0012] In addition, the polyurethane adhesive according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, component A and component B are included; By weight, component A comprises: 60-90 parts of polyol, 5-20 parts of first chain extender, 1-10 parts of second chain extender, 1-10 parts of crosslinking agent, and 1-5 parts of catalyst; Wherein, the first chain extender includes a diol compound, the second chain extender includes at least one of the first furanimide compound, the second furanimide compound, and the third furanimide compound, and the crosslinking agent includes at least one of the fourth furanimide compound and the fifth furanimide compound; By weight, component B comprises: 40-90 parts isocyanate and 20-50 parts polyurethane prepolymer.

[0013] In some embodiments of this application, the weight ratio of component A to component B is 1:(0.95~1.25). And / or, the weight parts M1 of the first chain extender, the weight parts M2 of the second chain extender and the weight parts M3 of the crosslinking agent satisfy the following relationship: (M2+M3) / (M1+M2+M3)≤0.5.

[0014] In some embodiments of this application, the polyol includes at least one of polypropylene oxide polyol, polypropylene oxide-ethylene oxide polyol, polytetrahydrofuran polyol, adipic acid polyester polyol, and castor oil. And / or, the diol compounds include at least one of ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol; And / or, the catalyst comprises at least one selected from 1,4-diazabicyclo[2.2.2]octane, triethylamine, dibutyltin dilaurate, and stannous octanoate; And / or, the isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and polymethylene polyphenyl polyisocyanate; And / or, the polyurethane prepolymer includes an isocyanate-terminated polyurethane prepolymer.

[0015] A fourth aspect of this application discloses an article of manufacture. According to embodiments of this application, the adhesive of the article of manufacture comprises at least the polyurethane adhesive described in the fourth aspect. Consequently, the adhesiveness, stability, and service life of the article of manufacture are significantly improved.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Detailed Implementation

[0017] The embodiments of this application are described in detail below by way of example, and are intended to explain this application, but should not be construed as limiting this application.

[0018] The first aspect of this application discloses an imine heterocyclic compound. According to embodiments of this application, the general chemical structural formula of the imine heterocyclic compound is shown in Formula I; Equation I: ; R is a C1~C10 alkyl, C5~C10 cycloalkyl, aryl or heterocyclic group; R1 and R2 are each independently an alkyl group having 0 to 3 carbon atoms; X is oxygen, sulfur, or nitrogen; n is any natural number from 1 to 3.

[0019] The imine heterocyclic compounds of the above embodiments of this application possess multiple hydroxyl groups, an imine structure, and a five-membered heterocyclic aromatic structure linked to the imine structure. This not only significantly enhances the stability of the compounds but also endows them with multiple properties such as crosslinking and chain extension. When applied to the preparation of polyurethane adhesives, they can significantly improve the comprehensive mechanical properties of polyurethane adhesives, such as shear strength and tensile strength, showing broad application prospects. Specifically: 1) The imine heterocyclic compounds of the present application have multiple hydroxyl groups, which endow them with the reactive properties to act as crosslinking agents or chain extenders; at the same time, the N atom in the imine structure (C=N) of the imine heterocyclic compound has a lone pair of electrons, which can act as a ligand to form stable Schiff base complexes with metal ions, etc., thus greatly improving the mechanical properties such as the bonding strength of polyurethane adhesives to substrates such as metals.

[0020] 2) Based on the structural characteristics described in 1) above, this imine heterocyclic compound has a five-membered heterocyclic aromatic structure linked to the imine structure. This not only significantly increases the stability of the compound and effectively avoids problems such as the easy hydrolysis of the imine bond under acid or alkaline conditions, but also greatly increases the molecular polarity of the five-membered heterocyclic aromatic structure, thereby enhancing the van der Waals forces between molecules. At the same time, the heteroatoms such as oxygen contain lone pairs of electrons, which can form hydrogen bonds with hydrogen atoms in urethane or urethane in polyurethane adhesives, enhancing the intermolecular forces. This further enhances the comprehensive mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0021] In the embodiments of this application, the C1-C10 alkyl groups may specifically be methyl, ethyl, n-propyl, isopropyl, isobutyl, tert-butyl, isopentyl, n-hexyl, n-heptyl, n-nonyl, etc., preferably ethyl or n-hexyl.

[0022] In the embodiments of this application, the C5~C10 cycloalkyl group can specifically be cyclopentyl, cyclopentenyl, cyclohexyl, cyclooctyl, spiro[4.5]decyl, etc., preferably cyclopentyl or cyclohexyl.

[0023] In the embodiments of this application, the aryl group includes substituted or unsubstituted monocyclic aryl groups (such as phenyl, phenyl with one hydrogen substituted on the benzene ring, phenyl with two hydrogen substituted on the benzene ring, phenyl with three hydrogen substituted on the benzene ring, etc.), substituted or unsubstituted polycyclic aryl groups (such as naphthyl, naphthyl with one hydrogen substituted on the naphthalene ring, naphthyl with two hydrogen substituted on the naphthalene ring, naphthyl with three hydrogen substituted on the naphthalene ring, anthracene, etc.), and is preferably monocyclic aryl.

[0024] In the embodiments of this application, the heterocyclic group includes substituted or unsubstituted pyridinyl, substituted or unsubstituted thiophene, substituted or unsubstituted triazine cyclogroup, etc., preferably triazine cyclogroup.

[0025] In the embodiments of this application, R1 and R2 are each independently an alkyl group with 0 to 3 carbon atoms, such as methyl, ethyl, n-propyl, etc. The alkyl chain length of R1 and R2 in this imine heterocyclic compound should not be too long (i.e., the alkyl chain length should not exceed 3) to avoid the problem of reduced stability of the imine heterocyclic compound due to excessively long alkyl chains. Specifically, when both R1 and R2 are 0, the "R" group in Formula I is directly connected to the N atom in "C=N", and the specific structural formula is as follows: .

[0026] According to some specific embodiments of this application, the imine heterocyclic compound includes at least one of a first furanimine compound, a second furanimine compound, a third furanimine compound, a fourth furanimine compound, and a fifth furanimine compound; The first furanimine compound satisfies the following conditions: 1) R is a C1~C10 alkyl or C5~C10 cycloalkyl; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; specifically, its general chemical formula is: ; The second furanimide compound satisfies the following conditions: 1) R is hydrogen or a phenyl group substituted with at least one C1-C10 alkyl group; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; specifically, its general chemical formula (i.e., R3, R4 and R5 are each independently hydrogen or C1-C10 alkyl groups, such as ethyl, n-propyl, isopropyl, isobutyl, tert-butyl, isopentyl, n-hexyl, n-heptyl, n-nonyl, etc.) is as follows: ; The third furanimide compound satisfies the following conditions: 1) R is hydrogen or a phenyl group substituted with at least one C1-C10 alkyl group; 2) R1 and R2 are each independently C1-C3 straight-chain alkyl groups; 3) X is oxygen; 4) n is 1; specifically, its general chemical formula (i.e., R3, R4, and R5 are each independently hydrogen or C1-C10 alkyl groups, such as ethyl, n-propyl, isopropyl, isobutyl, tert-butyl, isopentyl, n-hexyl, n-heptyl, n-nonyl, etc.) is as follows: Therefore, the third furanimide compounds contain five-membered heterocyclic aromatic structures and aryl structures such as phenyl, which further improves their stability. The fourth furanimine compound satisfies the following conditions: 1) R is a phenyl group substituted with at least one C1-C10 alkyl group and substituted with the structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; specifically, its general chemical formula (i.e., R3, R4 and R5 are each independently hydrogen or C1-C10 alkyl groups, such as ethyl, n-propyl, isopropyl, isobutyl, tert-butyl, isopentyl, n-hexyl, n-heptyl, n-nonyl, etc.) is as follows: Therefore, the third furanimide compounds contain five-membered heterocyclic aromatic structures and aryl structures such as phenyl, which further improves their stability. The fifth furanimine compound satisfies the following conditions: 1) R is a triazine cyclogroup substituted with at least one structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; specifically, its general chemical structural formula is as follows: Therefore, the third furanimine compounds contain five-membered heterocyclic aromatic structures and triazine cyclogroups and other heteroaryl structures, which further improve their stability. Formula II: .

[0027] It should be noted that in the chemical structural formulas mentioned above in this application, "*" only indicates that the chemical bond is connected or broken at that location, and is not part of the chemical structural group; at the same time, the function of "*" in the chemical structural formulas mentioned below is the same.

[0028] It should be noted that the above-mentioned imine heterocyclic compounds can be prepared by reacting an aldehyde group with a primary amine to generate an imine structure. The following are illustrative examples of the synthetic methods for the first, second, third, fourth, and fifth furanimine compounds: Step 1. Dissolve 5-hydroxymethylfurfural (HMF) in organic solvent 1 and heat to 40-90℃; select the diamine or polyamine corresponding to the target product. If the amine is liquid at room temperature, add it dropwise through a constant pressure dropping funnel. If the amine is solid at room temperature, dissolve it in organic solvent 2 and then add it dropwise through a constant pressure dropping funnel. The molar ratio of HMF to amine is determined according to the target product. For example, when preparing the first furanimide compound, the second furanimide compound, and the third furanimide compound, the molar ratio of HMF to diamine is 2:(1.05-1.3); for example, when preparing the fourth furanimide compound and the fifth furanimide compound, the molar ratio of HMF to triamine is 3:(1.05-1.3). During the dropwise addition and reaction, an inert atmosphere such as N2 or Ar is used for protection, and the reaction lasts for 1-24 hours. Step 2. After the reaction is complete, cool the solution in an ice bath for 30-120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization and then vacuum dried to obtain the final product.

[0029] Further, as preferred, organic solvent 1 and organic solvent 2 in step 1 can be one or more of methanol, ethanol, isopropanol, ethyl acetate, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), cyclohexane, n-hexane, and toluene; Furthermore, the preferred structural formula of the diamine in step 1 is: , where R is defined in the first furanimine compound mentioned above; Alternatively, the structural formula of the diamine is: R3, R4 and R5 are defined in the same way as those in the second furanimine compound mentioned above; Alternatively, the structural formula of the diamine is: R1, R2, R3, R4 and R5 are defined in the same way as those in the third furanimine compound mentioned above.

[0030] Furthermore, the preferred structural formula of the triamine in step 1 is: R3, R4 and R5 are defined in the same way as those in the fourth furanimine class of compounds mentioned above; Alternatively, the structural formula of the triamine is: .

[0031] Furthermore, the preferred specific operation process for recrystallization purification in step 3 is as follows: using ethanol or isopropanol as solvent, the crude product is added to the solvent, with 1g of crude product corresponding to 20~50g of solvent. The solution is then heated to 60~70℃ until the product is completely dissolved. The entire process is carried out under inert gas protection (N2 or Ar). After stirring for 30 minutes, the solution is placed in an ice bath to obtain the purified product.

[0032] A second aspect of this application discloses a chain extender. According to embodiments of this application, the chain extender comprises the imine heterocyclic compound described in the first aspect. Therefore, this chain extender exhibits excellent stability and, when applied to the preparation of polyurethane adhesives, can significantly improve the overall mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0033] A third aspect of this application discloses a crosslinking agent. According to embodiments of this application, the crosslinking agent comprises the imine heterocyclic compound described in the first aspect. Therefore, this crosslinking agent exhibits excellent stability and, when applied to the preparation of polyurethane adhesives, can significantly improve the overall mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0034] A fourth aspect of this application discloses a polyurethane adhesive. According to embodiments of this application, the polyurethane adhesive comprises the imine heterocyclic compound described in the first aspect. The polyurethane adhesive provided by this application possesses excellent flexibility and high mechanical strength. Furthermore, the shear strength can be tested according to standards such as GB / T 7124-2008 and ASTM D897, the tensile strength can be tested according to standards such as ASTM D638, and the elongation at break can be tested according to standards such as ASTM D412.

[0035] In some embodiments of this application, component A and component B are included; By weight, component A comprises: 60-90 parts of polyol, 5-20 parts of first chain extender, 1-10 parts of second chain extender, 1-10 parts of crosslinking agent, and 1-5 parts of catalyst; Wherein, the first chain extender includes a diol compound, the second chain extender includes at least one of the first furanimide compound, the second furanimide compound, and the third furanimide compound, and the crosslinking agent includes at least one of the fourth furanimide compound and the fifth furanimide compound; By weight, component B comprises: 40-90 parts isocyanate and 20-50 parts polyurethane prepolymer.

[0036] Based on the chemical structure design of the above-mentioned imine heterocyclic compounds, this application further uses the first furanimide compound, the second furanimide compound, and the third furanimide compound as chain extenders in polyurethane adhesives, and as crosslinking agents in polyurethane adhesives when combined with the fourth furanimide compound and the fifth furanimide compound, which significantly improves the comprehensive mechanical properties of polyurethane adhesives, such as shear strength and tensile strength.

[0037] In the embodiments of this application, the weight parts of the polyol can be 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 90 parts, or any value between any two of the above values, preferably 75-85 parts; the weight parts of the first chain extender can be 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, or any value between any two of the above values, preferably 10-15 parts; the weight parts of the second chain extender (1-10 parts) can be 2 parts, 4 parts, 5 parts, 6 parts, 8 parts, 10 parts, or any value between any two of the above values, preferably 3-7 parts; the weight parts of the crosslinking... The weight parts of the agent can be 2 parts, 4 parts, 5 parts, 6 parts, 8 parts, 10 parts, or any value between any two of the above values, preferably 3-7 parts; the weight parts of the catalyst can be 2 parts, 4 parts, 5 parts, or any value between any two of the above values, preferably 2-4 parts; the weight parts of the isocyanate can be 50 parts, 60 parts, 70 parts, 80 parts, or any value between any two of the above values, preferably 60-70 parts; the weight parts of the polyurethane prepolymer can be 20 parts, 30 parts, 40 parts, 50 parts, or any value between any two of the above values, preferably 30-40 parts.

[0038] According to some specific embodiments of this application, the weight ratio of component A to component B is 1:(0.95~1.25), for example, it can be 1:1.05, 1:1, etc. In use, component A and component B can be directly mixed by stirring according to the above weight ratio.

[0039] According to some specific embodiments of this application, the weight parts M1 of the first chain extender, the weight parts M2 of the second chain extender, and the weight parts M3 of the crosslinking agent satisfy the following relationship: (M2+M3) / (M1+M2+M3)≤0.5. The inventors have found that the addition amount of the above-mentioned second chain extender (i.e., the first furanimide compound, the second furanimide compound, and the third furanimide compound used as chain extenders in polyurethane adhesives) and crosslinking agent (i.e., the fourth furanimide compound and the fifth furanimide compound used as crosslinking agents in polyurethane adhesives) should not be excessive. This is because the introduction of aromatic structures enhances the bonding strength of polyurethane adhesives, but if the amount used exceeds a certain range, it will cause the polyurethane adhesive to lose its inherent flexibility, resulting in a decrease in elongation at break. Therefore, controlling the amount within the above range is more conducive to improving the overall performance of the polyurethane adhesive. Furthermore, the above "(M2+M3) / (M1+M2+M3)" means that the ratio of "the sum of the weight parts of the second chain extender M2 and the weight parts of the crosslinking agent M3" to "the sum of the weight parts of the first chain extender M1, the weight parts of the second chain extender M2 and the weight parts of the crosslinking agent M3" is ≤0.5.

[0040] According to some specific embodiments of this application, the polyol includes at least one of polypropylene oxide polyol, polypropylene oxide-ethylene oxide polyol, polytetrahydrofuran polyol, adipic acid polyester polyol and castor oil, preferably polypropylene oxide-ethylene oxide.

[0041] According to some specific embodiments of this application, the diol compound includes at least one selected from ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol, preferably ethylene glycol, diethylene glycol, and 1,4-butanediol.

[0042] According to some specific embodiments of this application, the catalyst includes at least one selected from 1,4-diazabicyclo[2.2.2]octane, triethylamine, dibutyltin dilaurate, and stannous octanoate; preferably 1,4-diazabicyclo[2.2.2]octane or triethylamine.

[0043] According to some specific embodiments of this application, the isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and polymethylene polyphenyl polyisocyanate; preferably diphenylmethane diisocyanate.

[0044] According to some specific embodiments of this application, the polyurethane prepolymer includes an isocyanate-terminated polyurethane prepolymer; preferably, it is obtained by prepolymerization of the polyol and isocyanate described above in this application, with a number average molecular weight of 3000-6000 g / mol, for example, 3000 g / mol, 3500 g / mol, 4000 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, or any value between any two of the above values.

[0045] It should be noted that polypropylene oxide-ethylene oxide polyol refers to a polyether polyol formed by the addition polymerization of polyol with propylene oxide and ethylene oxide, with the specific CAS number 9003-11-6. Commercially available products such as NJ-330 from Jurong Ningwu New Materials Co., Ltd. can be directly used. Polytetrahydrofuran polyol refers to a polyether polyol formed by the ring-opening polymerization of tetrahydrofuran, with the specific CAS number 25190-06-1. Commercially available products such as PolyTHF 1000 from BASF can be directly used. Adipic acid-based polyester polyol refers to a polyester polyol formed by the polymerization of adipic acid and diol, with the specific CAS number 25212-6-0. Commercially available products such as PE9956 from Huafeng Chemical can be directly used.

[0046] A fourth aspect of this application discloses an article of manufacture. According to embodiments of this application, the adhesive of the article of manufacture comprises at least the polyurethane adhesive described in the fourth aspect. Consequently, the adhesiveness, stability, and service life of the article of manufacture are significantly improved.

[0047] In the embodiments of this application, the above-mentioned products include prefabricated components for prefabricated buildings, building steel plates, roof waterproof membranes, plastic running tracks, elastic rubber mats, vehicle body structural components, etc. They are bonded with high strength by using the polyurethane adhesive provided in this application, while also possessing flexibility, which can buffer external impacts, improve their own stability and extend their service life.

[0048] The embodiments of this application are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0049] The main raw material information involved in the following examples and comparative examples is summarized below: Polypropylene oxide-ethylene oxide polyol 1: number average molecular weight 3000 g / mol, functional group degree 3, purchased from Jurong Ningwu New Materials Co., Ltd., product model NJ-330.

[0050] Polypropylene oxide-ethylene oxide polyol 2: number average molecular weight 500 g / mol, functional group degree 3, purchased from Jurong Ningwu New Materials Co., Ltd., product model NJ-305.

[0051] Isocyanate-terminated polyurethane prepolymer 1: It is prepolymerized with polyoxypropylene polyol (purchased from Jurong Ningwu New Materials Co., Ltd., product model NJ-210D) with a molecular weight of 1000 g / mol and a functional group degree of 2 and 4,4' diphenylmethane diisocyanate, with an average number average molecular weight of 4000 g / mol.

[0052] Polytetrahydrofuran polyol: Specifically, it is a polyether polyol polymerized by ring-opening of tetrahydrofuran. Its specific CAS number is 25190-06-1. It can be directly adopted if the manufacturer is BASF and the product model is PolyTHF 1000.

[0053] Example 1 This embodiment provides an imine heterocyclic compound, specifically named first furanimine compound 1, whose chemical structural formula is shown below: R stands for ethyl; The details are as follows: . The preparation method of the above-mentioned furanimine compounds includes the following steps: Step 1. Dissolve 40g HMF in 400ml ethanol and heat to 65℃; use 10g ethylenediamine and add it dropwise through a constant pressure dropping funnel for 15min under N2 atmosphere, and then continue the reaction for 60min. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol, and finally dried under vacuum to obtain the final product.

[0054] Example 2 This embodiment provides an imine heterocyclic compound, specifically named the first furanimine compound 2, which differs from Example 1 only in that: (1) In the preparation method, ethylenediamine is adjusted to 1,5-pentanediamine, and R is a C5 straight-chain alkyl group in the chemical structure of the resulting compound.

[0055] Example 3 This embodiment provides an imine heterocyclic compound, specifically named the first furanimine compound 3, which differs from Example 1 only in that: (1) In the preparation method, ethylenediamine was adjusted to 23.7g of 1,4-cyclohexanebis(methylamine).

[0056] Example 4 This embodiment provides an imine heterocyclic compound, specifically named the first furanimine compound 4, which differs from Example 1 only in that: (1) In the preparation method, ethylenediamine was adjusted to 19g of 1,4-cyclohexanediamine and dissolved in 100ml of isopropanol.

[0057] Example 5 This embodiment provides an imine heterocyclic compound, specifically named second furanimine compound 1, whose preparation method includes the following steps: Step 1. Dissolve 40g HMF in 400ml isopropanol and heat to 65℃; select 23g m-phenylenediamine and dissolve it in 100ml isopropanol, add it dropwise through a constant pressure dropping funnel for 15min under N2 atmosphere, and then continue the reaction for 60min. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol, and finally dried under vacuum to obtain the final product.

[0058] Example 6 This embodiment provides an imine heterocyclic compound, specifically named second furanimine compound 2, and its preparation method includes the following steps: Step 1. Dissolve 40g HMF in 400ml ethanol and heat to 65℃; select 20.4g of 2,4-diaminotoluene and dissolve it in 100ml isopropanol, add it dropwise through a constant pressure dropping funnel for 15min under N2 atmosphere, and then continue the reaction for 60min. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol and then vacuum dried to obtain the final product.

[0059] Example 7 This embodiment provides an imine heterocyclic compound, specifically named second furanimine compound 3, whose preparation method includes the following steps: Step 1. Dissolve 40g HMF in 400ml ethanol and heat to 65℃; select 22.7g of 1,2-diamino-3,5-xylene and add it dropwise through a constant pressure dropping funnel under N2 atmosphere for 15min, and then continue the reaction for 60min. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol, and finally dried under vacuum to obtain the final product.

[0060] Example 8 This embodiment provides an imine heterocyclic compound, specifically named third furanimine compound 1, whose preparation method includes the following steps: Step 1. Dissolve 40g HMF in 400ml ethanol and heat to 65℃; select 22.7g m-phenylenediamine and add it dropwise through a constant pressure dropping funnel under N2 atmosphere for 15min, and then continue the reaction for 60min. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol, and finally dried under vacuum to obtain the final product.

[0061] Example 9 This embodiment provides an imine heterocyclic compound, specifically named fourth furanimine compound 3, whose chemical structural formula is shown below: . The preparation method of the above-mentioned furanimine compounds includes the following steps: Step 1. Dissolve 40g HMF in 400ml isopropanol and heat to 65℃; select 15g of 2,4,6-triaminotoluene and add it dropwise through a constant pressure dropping funnel for 15min under N2 atmosphere, and then continue the reaction for 2h. Step 2. After the reaction is complete, cool the solution in an ice bath for 120 minutes, and then filter to obtain the crude product; Step 3. The crude product is purified by recrystallization from ethanol, and finally dried under vacuum to obtain the final product.

[0062] Example 10 This embodiment provides a polyurethane adhesive, comprising component A and component B in a weight ratio of 1:1; By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 8 parts of the first chain extender (specifically 1,4-butanediol), 8 parts of the second chain extender (specifically the first furanimide compound 1 obtained in Example 1), and 1.5 parts of the catalyst (specifically triethylamine). By weight, component B comprises: 60 parts of isocyanate (specifically 50 parts of 4,4'-diphenylmethane diisocyanate and 10 parts of 2,4'-diphenylmethane diisocyanate) and 40 parts of polyurethane prepolymer (specifically isocyanate-terminated polyurethane prepolymer 1).

[0063] The preparation method of the above-mentioned polyurethane structural adhesive includes the following steps: Step 1. Preparation of component A: 65 parts by weight of polyoxypropylene-ethylene oxide polyol 1, 25 parts by weight of polyoxypropylene-ethylene oxide polyol 2, 8 parts by weight of 1,4-butanediol, 8 parts by weight of first furanimide compound 1, and 1.5 parts by weight of triethylamine are mixed at 55°C for 30 min to obtain component A of polyurethane adhesive. Step 2. Preparation of Component B: Isocyanate component preparation: 50 parts by weight of 4,4'-diphenylmethane diisocyanate, 10 parts by weight of 2,4'-diphenylmethane diisocyanate, and 40 parts by weight of isocyanate-terminated polyurethane prepolymer (the prepolymer is made by prepolymerizing polyoxypropylene polyol with a molecular weight of 1000 g / mol and a functional group degree of 2 with 4,4'-diphenylmethane diisocyanate, with an average number-average molecular weight of 4000 g / mol) are mixed and stirred at 55°C under nitrogen protection for 25 min to obtain component B of the polyurethane adhesive.

[0064] Example 11 This embodiment provides a polyurethane adhesive, comprising component A and component B in a weight ratio of 1:1; By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 9 parts of first chain extender (specifically 1,4-butanediol), 5 parts of crosslinking agent (specifically the fourth furanimide compound 3 obtained in Example 9), and 1.5 parts of catalyst (specifically triethylamine). By weight, component B comprises: 60 parts of isocyanate (specifically 50 parts of 4,4'-diphenylmethane diisocyanate and 10 parts of 2,4'-diphenylmethane diisocyanate) and 40 parts of polyurethane prepolymer (specifically isocyanate-terminated polyurethane prepolymer 1).

[0065] The preparation method of the above-mentioned polyurethane structural adhesive includes the following steps: Step 1. Preparation of component A: 65 parts by weight of polyoxypropylene-ethylene oxide polyol 1, 25 parts by weight of polyoxypropylene-ethylene oxide polyol 2, 9 parts by weight of 1,4-butanediol, 5 parts by weight of fourth furanimide compound 3, and 1.5 parts by weight of triethylamine are mixed at 55°C for 30 min to obtain component A of polyurethane adhesive. Step 2. Preparation of Component B: Isocyanate component preparation: 50 parts by weight of 4,4'-diphenylmethane diisocyanate, 10 parts by weight of 2,4'-diphenylmethane diisocyanate, and 40 parts by weight of isocyanate-terminated polyurethane prepolymer (the prepolymer is made by prepolymerizing polyoxypropylene polyol with a molecular weight of 1000 g / mol and a functional group degree of 2 with 4,4'-diphenylmethane diisocyanate, with an average number-average molecular weight of 4000 g / mol) are mixed and stirred at 55°C under nitrogen protection for 25 min to obtain component B of the polyurethane adhesive.

[0066] Example 12 This embodiment provides a polyurethane adhesive, comprising component A and component B in a weight ratio of 1:1; By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 9 parts of first chain extender (specifically 1,4-butanediol), 6 parts of second chain extender (specifically the second furanimide compound 1 obtained in Example 5), and 1.5 parts of catalyst (specifically triethylamine). By weight, component B comprises: 60 parts of isocyanate (specifically 50 parts of 4,4'-diphenylmethane diisocyanate and 10 parts of 2,4'-diphenylmethane diisocyanate) and 40 parts of polyurethane prepolymer (specifically isocyanate-terminated polyurethane prepolymer 1).

[0067] The preparation method of the above-mentioned polyurethane structural adhesive includes the following steps: Step 1. Preparation of Component A: 65 parts by weight of polyoxypropylene-ethylene oxide polyol 1, 25 parts by weight of polyoxypropylene-ethylene oxide polyol 2, 9 parts by weight of 1,4-butanediol, 6 parts by weight of second furanimide compound 1, and 1.5 parts by weight of triethylamine are mixed at 55°C for 30 min to obtain component A of polyurethane adhesive. Step 2. Preparation of Component B: Isocyanate component preparation: 50 parts by weight of 4,4'-diphenylmethane diisocyanate, 10 parts by weight of 2,4'-diphenylmethane diisocyanate, and 40 parts by weight of isocyanate-terminated polyurethane prepolymer (the prepolymer is made by prepolymerizing polyoxypropylene polyol with a molecular weight of 1000 g / mol and a functional group degree of 2 with 4,4'-diphenylmethane diisocyanate, with an average number-average molecular weight of 4000 g / mol) are mixed and stirred at 55°C under nitrogen protection for 25 min to obtain component B of the polyurethane adhesive.

[0068] Example 13 This embodiment provides a polyurethane adhesive, comprising component A and component B in a weight ratio of 1:1; By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 8 parts of first chain extender (specifically 1,4-butanediol), 4 parts of second chain extender (specifically the second furanimide compound 1 obtained in Example 5), 4 parts of crosslinking agent (specifically the fourth furanimide compound 3 obtained in Example 9), and 1.5 parts of catalyst (specifically triethylamine). By weight, component B comprises: 60 parts of isocyanate (specifically 50 parts of 4,4'-diphenylmethane diisocyanate and 10 parts of 2,4'-diphenylmethane diisocyanate) and 40 parts of polyurethane prepolymer (specifically isocyanate-terminated polyurethane prepolymer 1).

[0069] The preparation method of the above-mentioned polyurethane structural adhesive includes the following steps: Step 1. Preparation of Component A: By weight, 65 parts of polyoxypropylene-ethylene oxide polyol 1, 25 parts of polyoxypropylene-ethylene oxide polyol 2, 8 parts of 1,4-butanediol, 4 parts of second furanimide compound 1, 4 parts of fourth furanimide compound 3, and 1.5 parts of triethylamine are mixed at 55°C for 30 min to obtain component A of the polyurethane adhesive; Step 2. Preparation of Component B: Isocyanate component preparation: 50 parts by weight of 4,4'-diphenylmethane diisocyanate, 10 parts by weight of 2,4'-diphenylmethane diisocyanate, and 40 parts by weight of isocyanate-terminated polyurethane prepolymer (the prepolymer is made by prepolymerizing polyoxypropylene polyol with a molecular weight of 1000 g / mol and a functional group degree of 2 with 4,4'-diphenylmethane diisocyanate, with an average number-average molecular weight of 4000 g / mol) are mixed and stirred at 55°C under nitrogen protection for 25 min to obtain component B of the polyurethane adhesive.

[0070] Example 14 This embodiment provides a polyurethane adhesive and its preparation method, which differs from Example 13 only in that: (1) 7 parts of the first chain extender (specifically 1,4-butanediol); (2) The second chain extender (specifically, the second furanimide compound 1 obtained in Example 5) was 8 parts; (3) The crosslinking agent (specifically, the fourth furanimide compound 3 obtained in Example 9) is 5 parts.

[0071] Example 15 This embodiment provides a polyurethane adhesive and its preparation method, which differs from Example 13 only in that: (1) By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 12 parts of the first chain extender (specifically 1,4-butanediol), 2 parts of the second chain extender (specifically the second furanimide compound 1 obtained in Example 5), 2 parts of the crosslinking agent (specifically the fourth furanimide compound 3 obtained in Example 9), and 1.5 parts of the catalyst (specifically triethylamine); (2) By weight, component B comprises: 65 parts of isocyanate (specifically 55 parts of 4,4'-diphenylmethane diisocyanate and 10 parts of 2,4'-diphenylmethane diisocyanate) and 40 parts of polyurethane prepolymer (specifically isocyanate-terminated polyurethane prepolymer 1).

[0072] Example 16 This embodiment provides a polyurethane adhesive and its preparation method, which differs from Example 13 only in that: (1) The second chain extender is specifically the second furanimide compound 2 obtained in Example 2.

[0073] Example 17 This embodiment provides a polyurethane adhesive and its preparation method, which differs from Example 13 only in that: (1) The second chain extender is specifically the third furanimide compound 1 obtained in Example 2.

[0074] Comparative Example 1 This comparative example provides a polyurethane adhesive and its preparation method, which differs from Example 13 only in that: (1) By weight, component A comprises: 90 parts of polyol (specifically 65 parts of polyoxypropylene-ethylene oxide polyol 1 and 25 parts of polyoxypropylene-ethylene oxide polyol 2), 16 parts of first chain extender (specifically 1,4-butanediol) and 1.5 parts of catalyst (specifically triethylamine).

[0075] Test case In this test example, the polyurethane adhesives obtained from the above embodiments and comparative examples were cured at a mass ratio of 1:1 and then their performance was tested in various aspects according to the test method "ISO527-2-2012". The test results are shown in Table 1.

[0076] Table 1

[0077] As shown in Table 1: 1) Compared with Comparative Example 1, the polyurethane adhesive provided in this application embodiment can significantly increase the shear strength and tensile strength of the adhesive by introducing specific imine heterocyclic compounds as crosslinking agents and / or as chain extenders. However, in terms of elongation at break, due to the introduction of aromatic structures, the rigid structure will reduce the flexibility of the colloid to a certain extent, thus the elongation at break is reduced to a certain extent.

[0078] 2) The test results of Examples 10 to 17 show that when using polyamines with different structures to prepare imine heterocyclic compounds as chain extenders, ethylenediamine aliphatic amines have a higher elongation at break than m-phenylenediamine aromatic amines, but aromatic amines have an advantage in adhesive strength. Further using trifunctional imine heterocyclic compounds as crosslinking agents further enhances mechanical strength, but also further reduces elongation at break; especially when "(M2+M3) / (M1+M2+M3)>0.5", as in Example 14, the decrease in elongation at break is more pronounced, with an elongation at break of only 14.7%.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An imine heterocyclic compound, characterized in that, The general chemical structure of the imine heterocyclic compounds is shown in Formula I; Equation I: ; R is a C1~C10 alkyl, C5~C10 cycloalkyl, aryl or heterocyclic group; R1 and R2 are each independently an alkyl group having 0 to 3 carbon atoms; X is oxygen, sulfur, or nitrogen; n is any natural number from 1 to 3.

2. The imine heterocyclic compound according to claim 1, characterized in that, The imine heterocyclic compounds include at least one of a first furanimide compound, a second furanimide compound, a third furanimide compound, a fourth furanimide compound, and a fifth furanimide compound; The first furanimine compound satisfies the following conditions: 1) R is a C1~C10 alkyl or C5~C10 cycloalkyl; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The second furanimine compound satisfies the following conditions: 1) R is hydrogen or a phenyl group substituted with at least one C1-C10 alkyl group; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The third furanimide compound satisfies the following conditions: 1) R is hydrogen or a phenyl substituted with at least one C1-C10 alkyl group; 2) R1 and R2 are each independently C1-C3 straight-chain alkyl groups; 3) X is oxygen; 4) n is 1; The fourth furanimine compound satisfies the following conditions: 1) R is a phenyl group substituted with at least one C1~C10 alkyl group and substituted with the structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; The fifth furanimine compound satisfies the following conditions: 1) R is a triazine cyclogroup substituted with at least one structure shown in Formula II; 2) R1 and R2 both have 0 carbon atoms; 3) X is oxygen; 4) n is 1; Formula II: .

3. The imine heterocyclic compound according to claim 2, characterized in that, The chemical formula of the first furanimide compound is shown below: R is methyl, ethyl, or propyl; Alternatively, the chemical formula of the second furanimide compound is shown below: R3, R4, and R5 are each independently hydrogen or C1-C10 alkyl groups; Alternatively, the chemical formula of the third furanimide compound is shown below: R1 and R2 are both methylene, and R3, R4 and R5 are each independently hydrogen or C1~C10 alkyl. And / or, the chemical formula of the fourth furanimide compound is shown below: R3, R4, and R5 are each independently hydrogen or C1-C10 alkyl groups; Alternatively, the chemical formula of the fifth furanimide compound is shown below; 。 4. A chain extender, characterized in that, The chain extender includes any one of the imine heterocyclic compounds according to claims 1 to 3.

5. A crosslinking agent, characterized in that, The crosslinking agent includes any one of the imine heterocyclic compounds according to claims 1 to 3.

6. A polyurethane adhesive, characterized in that, The polyurethane adhesive comprises any one of the imine heterocyclic compounds according to claims 1 to 3.

7. The polyurethane adhesive according to claim 6, characterized in that, Includes component A and component B; By weight, component A comprises: 60-90 parts of polyol, 5-20 parts of first chain extender, 1-10 parts of second chain extender, 1-10 parts of crosslinking agent, and 1-5 parts of catalyst; Wherein, the first chain extender includes a diol compound, the second chain extender includes at least one of the first furanimide compound, the second furanimide compound, and the third furanimide compound, and the crosslinking agent includes at least one of the fourth furanimide compound and the fifth furanimide compound; By weight, component B comprises: 40-90 parts isocyanate and 20-50 parts polyurethane prepolymer.

8. The polyurethane adhesive according to claim 7, characterized in that, The weight ratio of component A to component B is 1:(0.95~1.25). And / or, the weight parts M1 of the first chain extender, the weight parts M2 of the second chain extender and the weight parts M3 of the crosslinking agent satisfy the following relationship: (M2+M3) / (M1+M2+M3)≤0.

5.

9. The polyurethane adhesive according to claim 7, characterized in that, The polyols include at least one of polypropylene oxide polyols, polypropylene oxide-ethylene oxide polyols, polytetrahydrofuran polyols, adipic acid polyester polyols, and castor oil. And / or, the diol compounds include at least one of ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol; And / or, the catalyst comprises at least one of 1,4-diazabicyclo[2.2.2]octane, triethylamine, dibutyltin dilaurate, and stannous octanoate; And / or, the isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and polymethylene polyphenyl polyisocyanate; And / or, the polyurethane prepolymer includes an isocyanate-terminated polyurethane prepolymer.

10. An article characterized in that, The adhesive of the article includes at least the polyurethane adhesive as described in any one of claims 6 to 9.

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