Benzoxazine modifier, high-temperature resistant benzoxazine adhesive and its preparation method
By using perylene tetracarboxylic acid dianhydride modifiers copolymerized with benzoxazine resins, flexible long-chain benzoxazine copolymers were constructed, solving the problems of brittleness and interfacial compatibility of benzoxazine resins and enabling the application of adhesives with high toughness and high temperature resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHAOXING RES INST OF SHANGHAI UNIV
- Filing Date
- 2023-12-07
- Publication Date
- 2026-06-30
AI Technical Summary
While existing benzoxazine resins reduce brittleness during modification, they affect matrix interfacial compatibility and require high-temperature curing, resulting in high brittleness.
Perylene tetracarboxylic dianhydride compounds with aminoimidazole groups are used as modifiers and copolymerized with benzoxazine resins to form benzoxazine copolymers with flexible long-chain perylene ring structures. The toughness and mechanical properties are improved through copolymerization.
While maintaining high-temperature resistance, the toughness and mechanical properties of benzoxazine adhesives have been significantly improved, making them suitable for the extreme high-temperature environments in high-speed rail transportation.
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Figure CN117659013B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of adhesive technology, specifically a high-temperature resistant benzoxazine adhesive. Background Technology
[0002] The materials used in rail transit vehicles and equipment are diverse, and their adaptability varies. Adhesives with stable performance are needed to bond and fix these materials, ensuring the product's specific properties and reliability. High-speed railways encounter extreme high-temperature environments during operation; therefore, adhesives that maintain stable performance even at high temperatures are required to prevent material deformation and cracking caused by temperature changes.
[0003] In recent years, benzoxazine resins have shown great potential as adhesives in the rail transportation field due to their excellent high-temperature resistance, low curing shrinkage, no release of small molecules during curing, low water absorption, flame retardancy, low smoke and low toxicity, and room temperature storage. However, benzoxazine also has some drawbacks, such as the need for high-temperature curing, secondary processing, and high brittleness. To reduce its brittleness, a common modification method is to add a certain amount of thermoplastic resin to the benzoxazine resin for blending. Although this method is effective in reducing brittleness, it introduces problems related to matrix interfacial compatibility. Summary of the Invention
[0004] In view of this, the present disclosure provides a benzoxazine resin modifier to solve the problem that the current method of adding thermoplastic resin for blending modification to reduce the brittleness of benzoxazine resin can reduce its brittleness, but it will affect the compatibility of the matrix interface.
[0005] In addition, this disclosure also provides a high-temperature benzoxazine adhesive with excellent toughness, a benzoxazine modifier, and a method for preparing the benzoxazine adhesive.
[0006] In a first aspect, the benzoxazine modifier comprises:
[0007] Perylenetetracarboxylic dianhydride compounds containing an aminoimidazole group.
[0008] In this disclosure and possible embodiments, the compound is N,N'-bis(1-propylimidazolium)-3,4,9,10-perylenetetracarboxylic acid diimide or N,N'-bis(1-aminopropyl-3-propylimidazolium salt)-3,4,9,10-perylenetetracarboxylic acid diimide.
[0009] In this disclosure and possible embodiments, the N,N'-bis(1-aminopropyl-3-propylimidazolium salt)-3,4,9,10-perylenetetracarboxylic acid diimide is N,N'-bis(1-aminopropyl-3-propylimidazolium bromide)-3,4,9,10-perylenetetracarboxylic acid diimide.
[0010] Secondly, the method for preparing the benzoxazine modifier described in the first aspect includes:
[0011] Under inert gas protection, perylene tetracarboxylic dianhydride and aminoimidazolium salt react in isobutanol to obtain the reaction product, which is the perylene tetracarboxylic dianhydride compound with an aminoimidazolium group.
[0012] In this disclosure and possible embodiments, in the reaction of perylene tetracarboxylic dianhydride and aminoimidazolium salt in isobutanol, the perylene tetracarboxylic dianhydride and the aminoimidazolium salt are configured in a molar ratio of 1:2; and / or,
[0013] The isobutanol is prepared in such a way that it is used to impregnate the perylene tetracarboxylic dianhydride and the aminoimidazolium salt; and / or,
[0014] The inert gas is configured as nitrogen; and / or,
[0015] In the reaction of perylene tetracarboxylic dianhydride and aminoimidazolium salt in isobutanol, the reaction is carried out under stirring, the reaction temperature is set to 90°C, and the reaction time is set to 24 h; and / or,
[0016] The method further includes: after the reaction is completed, cooling the reaction product to room temperature to precipitate a solid, filtering and washing the solid, and then adding it to an alkaline solution; heating the alkaline solution system for a set time, followed by filtering and washing to obtain the perylene tetracarboxylic dianhydride compound with an aminoimidazole group; and / or,
[0017] In the reaction of perylene tetracarboxylic dianhydride and aminoimidazolium salt in isobutanol, the aminoimidazolium salt is configured as 3-aminopropylimidazolium salt, and the benzoxazine modifier N,N'-bis(1-propylimidazolium)-3,4,9,10-perylene tetracarboxylic acid diimide is obtained based on the reaction of the perylene tetracarboxylic dianhydride and the 3-aminopropylimidazolium salt.
[0018] In this disclosure and possible embodiments, under an inert atmosphere, the N,N'-bis(1-propylimidazolium)-3,4,9,10-perylenetetracarboxylic acid diimide reacts with 3-bromopropylamine hydrobromide in ethanol. The reaction product obtained by filtration is recrystallized and vacuum dried to obtain the benzoxazine modifier N,N'-bis(1-aminopropyl-3-propylimidazolium bromide)-3,4,9,10-perylenetetracarboxylic acid diimide; and / or,
[0019] The alkaline solution is prepared as a 5% NaOH solution, the heating temperature of the alkaline solution system is set to 90°C, and the set time is set to 30 min; and / or,
[0020] The filtered solid was washed with deionized water and ethanol, respectively.
[0021] Thirdly, the high-temperature resistant benzoxazine adhesive comprises the following components:
[0022] Benzoxazine, epoxy resin, and the benzoxazine modifier described in the first aspect.
[0023] In this disclosure and possible embodiments, the benzoxazine is 10-50 parts by weight, the epoxy resin is 50-90 parts, and the benzoxazine modifier is 5-25 parts.
[0024] Fourthly, the method for preparing the adhesive described in the third aspect includes:
[0025] The melamine mixture of the benzoxazine, epoxy resin and benzoxazine modifier is dissolved in an organic solvent. The organic solution of the melamine mixture is washed with an alkaline solution and then washed with water until neutral. After washing with water, the organic solvent in the organic solution is removed to obtain the benzoxazine adhesive.
[0026] In this disclosure and possible embodiments, a method for preparing the melt mixture of the benzoxazine, epoxy resin, and benzoxazine modifier includes: heating and melting the mixture of the benzoxazine, epoxy resin, and benzoxazine modifier at 100°C, and stirring for 30 minutes to obtain the melt mixture; and / or,
[0027] A method for removing the organic solvent from the organic solution to obtain the benzoxazine adhesive includes: removing the organic solvent from the organic solution by distillation to obtain the benzoxazine adhesive; wherein the organic solvent is chloroform; and / or,
[0028] The method of washing the organic solution of the molten mixture with an alkaline solution and then washing it with water until neutral includes: washing the organic solution of the molten mixture with deionized water until neutral.
[0029] This disclosure has the following beneficial effects:
[0030] The benzoxazine modifier disclosed herein is a monomer with flexible chains and multiple functional groups that can react with benzoxazine through molecular design and synthesis. Benzoxazine undergoes a copolymerization reaction with the modifier to construct a novel benzoxazine copolymer with a perylene ring structure. This perylene ring structure is a flexible long chain. The flexible long chain forms a network structure through copolymerization with the benzoxazine monomer, which can improve the mechanical properties of the copolymer and increase its toughness. Because this disclosure improves the toughness of benzoxazine resin through copolymerization, it can effectively solve the problem of reducing the brittleness of benzoxazine by blending thermoplastic resins and affecting the interfacial compatibility of the matrix.
[0031] Meanwhile, the benzoxazine adhesive disclosed herein, due to the flexible long chain and network structure formed by the copolymer of benzoxazine and the modifier, has superior mechanical properties and toughness on the basis of high temperature resistance, thus providing a high-temperature resistant benzoxazine adhesive with excellent and stable performance during operation and under extreme high temperature environments for high-speed rail transit. Attached Figure Description
[0032] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:
[0033] Figure 1 This is the reaction equation for preparing the benzoxazine modifier according to an embodiment of this disclosure. Detailed Implementation
[0034] The present disclosure is described below based on embodiments; however, it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, certain specific details are described in detail. However, those skilled in the art will fully understand the present disclosure for the parts not described in detail.
[0035] Furthermore, unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to."
[0036] The epoxy resin, benzoxazine, and other raw material components used in the following embodiments of this disclosure can all be obtained through commercial channels.
[0037] I. Preparation of benzoxazine modifier:
[0038] Figure 1 This is the reaction equation for the preparation of the benzoxazine modifier according to embodiments of this disclosure. (Combined with...) Figure 1 As shown: The preparation method of the benzoxazine modifier includes the following specific steps:
[0039] 3.923 g of perylenetetracarboxylic dianhydride and 3.75 g of 3-aminopropylimidazolium bromide were added to 200 mL of isobutanol and heated to 90 °C under nitrogen protection for 24 h with stirring. After the reaction, the product was cooled to room temperature, the precipitated solid was filtered and washed with deionized water and ethanol, respectively. The resulting red crude product was added to 150 mL of 5% NaOH solution and heated to 90 °C for 30 min. After filtration, the product was washed with deionized water and ethanol, respectively, to remove unreacted perylenetetracarboxylic dianhydride. After vacuum drying, product A was obtained, which was 5.4 g of N,N'-di(1-propylimidazolium)-3,4,9,10-perylenetetracarboxylic acid diimide, with a yield of 89%.
[0040] 3.03 g of N,N'-bis(1-propylimidazolium)-3,4,9,10-perylenetetracarboxylic acid diimide and 0.438 g of 3-bromopropylamine hydrobromide were added to 100 mL of ethanol and heated to 80 °C under a nitrogen atmosphere for 24 h. After the reaction, the product was cooled to room temperature, filtered, and washed three times with ethanol to obtain a red product. Further recrystallization from ethanol and vacuum drying yielded product B, which was 3.2 g of benzoxazine-modified N,N'-bis(1-aminopropyl-3-propylimidazolium)-3,4,9,10-perylenetetracarboxylic acid diimide, with a yield of 93%.
[0041] II. Preparation of high-temperature resistant benzoxazine adhesives:
[0042] Epoxy resin, benzoxazine monomer, and benzoxazine modifier N,N'-bis(1-aminopropyl-3-propylimidazolium salt)-3,4,9,10-perylenetetracarboxylic acid diimide were added to a flask at a set mass ratio, heated to melt at 100°C, and stirred rapidly for 30 min until homogeneous. The mixture was then cooled to room temperature to obtain a high-temperature resistant benzoxazine adhesive with the set mass ratio.
[0043] Example
[0044] Bisphenol A type epoxy resin (liquid, average epoxy value 0.51) and bisphenol A type benzoxazine monomer were mixed at a mass percentage ratio of 1:2. Then, benzoxazine modifier N,N'-bis(1-aminopropyl-3-propylimidazolium salt)-3,4,9,10-perylenetetracarboxylic acid diimide was prepared according to different mass percentages to obtain benzoxazine adhesive samples with different mass percentages.
[0045] The physical and mechanical properties of the samples with different proportions were tested, and the specific test results are shown in Table 1.
[0046] Table 1 Performance test results of samples with different proportions
[0047] Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Modifier mass ratio 0 5％ 10％ 15％ 20％ 25％ Glass transition temperature, / ℃ 225.3 215.4 206.4 199.6 195.6 185.2 <![CDATA[Impact strength, / kJ·m －2 > 1.91 2.51 3.91 4.52 5.12 6.22 Bending strength, / MPa 66.3 67.2 70.6 72.2 75.9 79.3
[0048] As can be seen from the performance comparison in Table 1, after the adhesives of samples 1-6 are cured, compared with the adhesive of sample 1, the glass transition temperature of the benzoxazine adhesives of samples 2-6 with added benzoxazine modifier is reduced by at least 10°C. The more modifier added, the more obvious the reduction, thus effectively improving the toughness. At the same time, the impact strength and flexural strength of the benzoxazine adhesives of samples 2-6 are significantly improved. This fully demonstrates that the benzoxazine modifier of the present invention can not only enhance the toughness of benzoxazine, but also improve its mechanical properties.
[0049] In summary, the benzoxazine modifier disclosed herein is a novel benzoxazine copolymer with a perylene tetracarboxylic dianhydride compound containing a long flexible chain with an aminoimidazolium group, synthesized through molecular design. The modifier monomer is a conjugated macrocyclic compound with active sites on its outer ring. After copolymerization with benzoxazine, modification is achieved by introducing different substituent groups at the active sites on the outer ring, further improving the mechanical properties and heat resistance of the benzoxazine material. The perylene ring, acting as a crosslinking point in the crosslinking network structure, allows for control of the crosslinking point density by adjusting the amount of anhydride added.
[0050] On the other hand, the modifier acid anhydride can react with the hydroxyl groups in the epoxy resin to generate carboxylic acids, catalyzing the ring-opening polymerization of benzoxazine to produce phenolic hydroxyl groups. The generated phenolic hydroxyl groups can then further catalyze the reaction between the epoxy resin and acid anhydride to form hydroxyl groups, which in turn react with the acid anhydride to form carboxylic acids, catalyzing the ring-opening reaction of benzoxazine. This forms a mutually catalyzing curing system, with a curing temperature significantly lower than that of benzoxazine self-polymerization. Furthermore, introducing amino groups can catalyze the ring-opening curing reaction of benzoxazine, further reducing the curing temperature.
[0051] The imidazole group further promotes the copolymerization reaction between benzoxazine and epoxy resin, inhibits the crosslinking between amino and epoxy groups, optimizes the curing process parameters of benzoxazine adhesives, and ensures heat resistance, thus outperforming common primary amine curing agents such as DDM and DDS. Furthermore, the flexible long chains, through copolymerization with benzoxazine monomers to form a network structure, can improve the mechanical properties of the copolymer and increase its toughness.
[0052] The embodiments described above are merely illustrative of implementation methods of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent disclosure. It should be noted that those skilled in the art can make various modifications, equivalent substitutions, and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent disclosure should be determined by the appended claims.
Claims
1. A benzoxazine adhesive, characterized in that, It includes the following components: Benzoxazine, epoxy resin and benzoxazine modifier; The benzoxazine modifier is N,N'-bis(1-aminopropyl-3-propylimidazolium salt)-3,4,9,10-perylenetetracarboxylic acid diimide.
2. The benzoxazine adhesive according to claim 1, characterized in that, The benzoxazine comprises 10-50 parts by weight, the epoxy resin comprises 50-90 parts by weight, and the benzoxazine modifier comprises 5-25 parts by weight.
3. The method for preparing the adhesive according to claim 1 or 2, characterized in that, include: The melamine, epoxy resin and benzoxazine modifier are dissolved in an organic solvent. The organic solution of the melamine is washed with an alkaline solution and then washed with water until neutral. After washing with water, the organic solvent in the organic solution is removed to obtain the benzoxazine adhesive.
4. The method for preparing the adhesive according to claim 3, characterized in that: A method for preparing the melt mixture of benzoxazine, epoxy resin and benzoxazine modifier includes: heating and melting the mixture of benzoxazine, epoxy resin and benzoxazine modifier at 100°C and stirring for 30 min to obtain the melt mixture.
5. The method for preparing the adhesive according to claim 3, characterized in that: A method for removing the organic solvent from the organic solution to obtain the benzoxazine adhesive includes: removing the organic solvent from the organic solution by distillation to obtain the benzoxazine adhesive; wherein the organic solvent is chloroform.
6. The method for preparing the adhesive according to claim 3, characterized in that: The method of washing the organic solution of the molten mixture with an alkaline solution and then washing it with water until neutral includes: washing the organic solution of the molten mixture with deionized water until neutral.