Bio-based silane coupling agent as well as preparation method and application thereof
The bio-based silane coupling agent prepared by mercapto-alkene click chemistry utilizes the rigid benzene ring and long alkane side chain of cashew phenol to form an interfacial barrier, solving the problem of reduced adhesive strength of traditional coupling agents under high temperature and high humidity conditions, and realizing the high durability and environmentally friendly synthesis of adhesives under harsh conditions.
Patent Information
- Application Number
- CN202511715505.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-02-24
AI Technical Summary
Traditional silane coupling agents have insufficient interfacial bonding stability in high temperature and high humidity environments, which leads to a decrease in the bonding strength of the adhesive under harsh working conditions and makes it impossible to meet the requirements for long-term reliable application.
A pyrolysis-type free radical photoinitiator was used to initiate a click chemical reaction of mercapto-alkene, which efficiently couples cashew phenol derivatives with mercaptosilanes to prepare a bio-based silane coupling agent. This forms an interfacial barrier between a rigid benzene ring and a long alkane side chain, enhancing the thermodynamic stability and hydrophobicity of the interfacial layer.
It significantly improves the adhesion strength retention rate of adhesives under high temperature and high humidity environments, provides a green and environmentally friendly synthesis process, and is suitable for a variety of adhesive systems, especially exhibiting excellent durability in fields such as new energy vehicles and electronic packaging.
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Abstract
Description
Technical Field
[0001] This invention relates to a bio-based silane coupling agent, its preparation method and application, belonging to the field of organic materials chemistry technology. Background Technology
[0002] In the field of adhesives, silane coupling agents typically serve as "molecular bridges" between organic polymer bases and inorganic fillers. Their core function lies in effectively improving the interfacial compatibility between inorganic fillers and organic polymer bases through chemical bonding, thereby increasing the filler loading and significantly enhancing the mechanical strength and durability of the cured colloid. More importantly, they can improve the adhesion between the colloid and the substrate. Although traditional silane coupling agents perform well under normal conditions, their interfacial adhesion stability remains insufficient under harsh aging conditions of continuous high temperature and humidity. Water molecules in the environment preferentially penetrate and attack the chemical bonds formed between the coupling agent and the inorganic substrate, triggering interfacial hydrolysis and desorption, ultimately leading to a sharp decrease in adhesive strength and even interfacial failure. This technical bottleneck severely restricts the long-term reliable application of adhesives under harsh conditions. Cashew nut shell extract, a natural monophenol extracted from cashew nut shell liquid, has a highly distinctive molecular structure: the phenolic ring provides rigidity and thermal stability, while the long fatty chain provides excellent flexibility and hydrophobicity. This combination of rigidity and flexibility in its molecular structure and its derivatives makes it an ideal starting point for designing a new generation of bio-based interfacial modifiers. However, how to efficiently and precisely integrate cashew phenol or its derivatives into the molecular structure of coupling agents and fully utilize their properties at the interface layer remains a challenge in this field. Summary of the Invention
[0003] To address the problem of insufficient resistance to damp heat aging in existing coupling agents used in adhesives, this invention provides a bio-based silane coupling agent, its preparation method, and its application, which effectively solves this problem.
[0004] This invention creatively utilizes a pyrolysis-type free radical photoinitiator to initiate a mercapto-alkene click chemistry reaction, which boasts advantages such as mild conditions, high efficiency, and well-defined product structures. Through this reaction, the double bonds of the side chains of cashew nut shellac or its derivatives are efficiently coupled with a mercaptosilane of a specific structure, successfully preparing a novel cashew nut shellac-modified silane coupling agent. Surprisingly and beyond expectations, compared to control samples using traditional silane coupling agents, the adhesive system using this modified coupling agent exhibited a breakthrough improvement in bond strength retention after long-term high-temperature and high-humidity aging tests. This superior performance may stem from a unique "barrier layer" constructed by the cashew nut shellac molecule at the interface: its rigid benzene ring enhances the thermodynamic stability of the interface layer, while the long alkane chain forms a dense hydrophobic barrier, synergistically significantly slowing down the erosion rate of chemical bonds formed at the colloid-substrate interface by moisture. This discovery not only provides a novel and efficient solution to the persistent problem of interface resistance to humid heat aging but also opens up new pathways for the high-value-added application of biomass resources.
[0005] The technical solution of the present invention to solve the above problems is as follows: The first objective of this invention is to provide a bio-based silane coupling agent, prepared from raw materials comprising the following components via a photo-initiated thiol-alkene click chemistry reaction: a cashew nut phenol derivative, a thiol silane coupling agent, and a photoinitiator, wherein the molar ratio of the carbon-carbon double bond in the cashew nut phenol derivative, the thiol group in the thiol silane coupling agent, and the photoinitiator is 1:0.4-1:0.01-0.05.
[0006] Furthermore, the molecular structure of the cashew phenol derivative is shown in Formula 1. Formula 1:
[0007] Where R can be
[0008] Any one of them.
[0009] Furthermore, the mercaptosilane coupling agent includes at least one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.
[0010] Further, the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoylphenylphosphine acid (TPO-L), 1-hydroxycyclohexylphenyl ketone (184), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), methyl benzoylformate (MBF), 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone (369), 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone (907), and benzoin dimethyl ether (651).
[0011] A second aspect of this invention provides a method for preparing the aforementioned bio-based silane coupling agent, comprising the following steps: a. Mix the cashew phenol derivative, the mercaptosilane coupling agent, and the photoinitiator, and stir under a nitrogen atmosphere until they are uniformly dissolved to form a reaction mixture; b. Under ultraviolet light irradiation, allow the reaction mixture obtained in step a to undergo a mercapto-alkene click chemistry reaction until the mercapto characteristic peak disappears as detected by spectroscopic methods, at which point the reaction is complete, and the bio-based silane coupling agent is obtained.
[0012] A third aspect of the present invention provides an adhesive composition comprising the aforementioned bio-based silane coupling agent.
[0013] Furthermore, the bio-based silane coupling agent has a mass fraction of 0.5%-5% in the adhesive composition.
[0014] The fourth aspect of this invention provides the application of the aforementioned bio-based silane coupling agent in the preparation of high-temperature and high-humidity aging resistant adhesives.
[0015] The beneficial effects of this invention are as follows: Compared with the prior art, the cashew phenol-based coupling agent based on photoinitiated click chemistry provided by this invention has the following significant beneficial effects: Highly efficient interfacial bonding: Prepared using a mercapto-olefin click chemistry reaction, this coupling agent has a well-defined molecular structure and high reaction efficiency. One end of the coupling agent forms a strong chemical bond with the inorganic substrate via a silane group, while the other end tightly binds to the organic polymer through the rigid structure of cashew phenol and the stable carbon-sulfur bonds formed after the reaction, thus enhancing the initial interfacial adhesion strength.
[0016] Exceptional high temperature and humidity resistance: The coupling agent significantly improves the durability of the adhesive interface under harsh, humid and hot environments. The rigid benzene ring and long alkane side chain of cashew phenol form a dense and stable hydrophobic barrier at the interface, effectively preventing water molecule erosion and resulting in a breakthrough improvement in the retention rate of adhesive strength after long-term high temperature and humidity aging.
[0017] Green and environmentally friendly, and resource-sustainable: Using renewable cashew nutshell derivatives as raw materials partially replaces dependence on petroleum-based resources, aligning with the trend of green chemistry development. Simultaneously, photo-initiated click chemistry itself possesses advantages such as high atom economy and mild conditions, collectively constituting an environmentally friendly synthetic process.
[0018] Broad application prospects: The cashew phenol-based coupling agent prepared by this invention is suitable for various adhesive systems, such as acrylic, epoxy, and polyurethane. It can be further applied to fields with extremely high requirements for high temperature and humidity aging resistance, such as new energy vehicles, electronic packaging, and photovoltaics, and has great market application potential. Detailed Implementation
[0019] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0020] Example 1 a. 356g of cashew phenol derivative CARDOLITE Ultra LITE 513 (molecular structural formula 2), 200g of 3-mercaptopropyltrimethoxysilane, and 9g of photoinitiator TPO were sequentially added to a glass reactor and stirred under a nitrogen atmosphere until the photoinitiator was completely dissolved and homogeneous. Structure 2:
[0021] b. Turn on the UVLED 365nm light source to initiate the reaction until the thiol groups have completely reacted, then stop the UV light irradiation; discharge the material to obtain the bio-based silane coupling agent A1.
[0022] 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of Al, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0023] Example 2 a. Add 356g of cashew phenol derivative CARDOLITE Ultra LITE 513, 274g of 3-mercaptopropyltrimethoxysilane, and 11g of photoinitiator TPO sequentially into a glass reactor and stir under a nitrogen atmosphere until the photoinitiator is completely dissolved and homogeneous. b. Turn on the UVLED 365nm light source to initiate the reaction until the thiol groups have completely reacted, then stop the UV light irradiation; discharge the material to obtain the bio-based silane coupling agent A2.
[0024] 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of A2, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0025] Example 3 a. Add 356g of cashew phenol derivative CARDOLITE Ultra LITE 513, 352g of 3-mercaptopropyltrimethoxysilane, and 14g of photoinitiator TPO sequentially into a glass reactor and stir under a nitrogen atmosphere until the photoinitiator is completely dissolved and homogeneous. b. Turn on the UVLED 365nm light source to initiate the reaction until the thiol groups have completely reacted, then stop the UV light irradiation; discharge the material to obtain the bio-based silane coupling agent A3.
[0026] Add 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of A3, and 2 parts of photoinitiator TPO to a stirred tank in sequence, stir until the photoinitiator is dissolved and the mixture is uniform, and then discharge the material for later use.
[0027] Comparative Example 1 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred under a nitrogen atmosphere until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0028] Comparative Example 2 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of CARDOLITE NC-513, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred under a nitrogen atmosphere until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0029] Comparative Example 3 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of 3-mercaptopropyltrimethoxysilane, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred under a nitrogen atmosphere until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0030] Comparative Example 4 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of γ-glycidyl etheroxypropyltrimethoxysilane, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred under a nitrogen atmosphere until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0031] Comparative Example 5 40 parts of commercially available DR-U028FS polyurethane acrylate resin, 2 parts of di[2-(methacryloyloxy)ethyl] phosphate, 28 parts of isobornyl acrylate, 15 parts of N,N-dimethylacrylamide, 5 parts of tetrahydrofuran acrylate, 5 parts of tricyclodecanediethanol diacrylate, 3 parts of γ-methacryloyloxypropyltrimethoxysilane, and 2 parts of photoinitiator TPO were added sequentially to a stirred tank and stirred under a nitrogen atmosphere until the photoinitiator was dissolved and the mixture was homogeneous. The mixture was then discharged for later use.
[0032] Performance testing Sample preparation: Glass and 3003 aluminum were selected as the substrates for this test. Glass and 3003 aluminum were bonded together with adhesive for both the example and comparative examples, with the adhesive layer thickness controlled at 1 mm. The glass side was irradiated with 3000 mJ / cm² using a 365nm LED light source. 2 The material is cured and made into a standard sample for subsequent performance testing.
[0033] Shear strength: Tested in accordance with GB / T7124-2008 Determination of tensile shear strength of adhesives.
[0034] High temperature and high humidity aging test: The cured samples of the example and comparative examples were placed in a constant temperature and humidity chamber at 85°C and 85% humidity for 2000 hours for aging. After being taken out, they were placed at 25°C and 50% humidity for 4 hours for testing.
[0035] The test results are shown in Table 1: Table 1: Test Results of Examples and Comparative Examples
[0036] The test results above show that the bio-based silane coupling agent of the present invention has higher initial shear strength and strength retention rate after high temperature and high humidity aging compared with conventional coupling agents, and can be applied to more demanding service conditions.
[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A bio-based silane coupling agent, characterized in that, The raw material comprises the following components: cashew nut phenol derivative, mercaptosilane coupling agent and photoinitiator, wherein the molar ratio of carbon-carbon double bond in the cashew nut phenol derivative, mercapto group in the mercaptosilane coupling agent and photoinitiator is 1:0.4-1:0.01-0.
05.
2. The bio-based silane coupling agent according to claim 1, characterized in that, The molecular structure of the cashew phenol derivative is shown in Formula 1. Formula 1: Where R can be Any one of them.
3. The bio-based silane coupling agent according to claim 1, characterized in that, The mercaptosilane coupling agent includes at least one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.
4. The bio-based silane coupling agent according to claim 1, characterized in that, The photoinitiator includes at least one of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoylphenylphosphine acid (TPO-L), 1-hydroxycyclohexylphenyl ketone (184), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), methyl benzoylformate (MBF), 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone (369), 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone (907), and benzoin dimethyl ether (651).
5. A method for preparing a bio-based silane coupling agent as described in any one of claims 1-4, characterized in that, Includes the following steps: a. Mix the cashew phenol derivative, the mercaptosilane coupling agent, and the photoinitiator, and stir under a nitrogen atmosphere until they are uniformly dissolved to form a reaction mixture; b. Under ultraviolet light irradiation, allow the reaction mixture obtained in step a to undergo a mercapto-alkene click chemistry reaction until the mercapto characteristic peak disappears as indicated by spectroscopic methods, at which point the reaction is complete, and the bio-based silane coupling agent is obtained.
6. An adhesive composition, characterized in that, It contains a bio-based silane coupling agent as described in any one of claims 1-4.
7. The adhesive composition according to claim 6, characterized in that, The bio-based silane coupling agent has a mass fraction of 0.5%-5% in the adhesive composition.
8. The application of a bio-based silane coupling agent as described in any one of claims 1-4 in the preparation of a high-temperature and high-humidity aging resistant adhesive.