Preparation method and application of high-temperature-resistant flame-retardant polyimide copolymerized epoxy resin

Abstract

The invention discloses a preparation method of high-temperature-resistant flame-retardant polyimide copolymerized epoxy resin. The preparation method comprises the following steps: S1, synthesizing a chlorinated bisphenol A aliphatic diamine compound; s2, synthesizing an imine chlorinated bisphenol A aliphatic diamine compound; and S3, preparing the polyimide copolymerized bisphenol A epoxy resin based on the imine chlorinated bisphenol A aliphatic diamine compound. The polyimide copolymerized epoxy resin is prepared based on the characteristics of strong adhesive force and corrosion resistance of epoxy resin. Polyimide and epoxy resin are mixed and modified to form the high-temperature-resistant polyimide modified epoxy resin. Compared with the existing epoxy resin, the problems of poor high temperature resistance and weather resistance of the epoxy resin are solved, and the high temperature resistance, flame retardance and weather resistance of the resin can be greatly improved on the basis of strong adhesive force and corrosion resistance by adopting the polyimide copolymerized bisphenol A epoxy resin.

Description

Technical Field

[0001] This invention discloses a method for preparing and applying a high-temperature resistant flame-retardant polyimide copolymer epoxy resin, relating to the field of high-temperature resistant resin technology. Background Technology

[0002] High-temperature resistant polyimide-modified epoxy resin is a special type of epoxy resin, a composite material obtained by modifying traditional epoxy resin with the addition of polyimide.

[0003] Polyimide is a class of high-performance engineering plastics with excellent high-temperature resistance, chemical stability, mechanical strength, and electrical insulation properties. However, due to the difficulty in processing polyimide itself, its application range is somewhat limited.

[0004] For example, in existing technologies, the team led by Gu Heping at Nanjing University of Technology synthesized flexible diamine monomers bisphenol A type diether diamine (BAPOPP) and dianhydride monomers bisphenol A type diether dianhydride (BPDEDA) using a novel synthetic process to prepare BAPOPP+ODA (4,4'-diaminodiphenyl ether) / PMDA (pyromellitic dianhydride) copolymer polyimide. After BAPOPP was copolymerized and modified with ODA / PMDA type polyimide, the glass transition temperature (Tg) reached a minimum of 277.9℃ when the BAPOPP content was 50%.

[0005] Zhang Chunqi (CN202211550311.6) developed a double-terminated polyimide-modified epoxy resin with a softening point ≤70℃ and a molecular weight of 1000-5000. This polyimide-modified epoxy resin has advantages such as long service life, good thermal conductivity, excellent high temperature resistance, and good mechanical properties, and is suitable for use in the preparation of insulating varnishes.

[0006] Wei Zhilong (CN202210588175.3) synthesized a water-soluble polyimide-modified epoxy resin and its heat-resistant and anti-corrosion coating. The preparation method uses water-soluble polyimide-modified epoxy resin and water-based modified fatty amine curing agent as film-forming substances. It has excellent heat resistance and corrosion resistance. Its heat resistance to crude oil temperature of 90-120℃ can reach 1000h, which greatly improves the corrosion resistance of the coating under high temperature conditions on the inner wall of storage tank.

[0007] Wu Dezhen (CN201310301051.3) prepared an epoxy resin composite material with high-performance polyimide fiber as reinforcement, which has excellent comprehensive mechanical properties and interfacial adhesion strength.

[0008] Patent CN 102639640 A discloses a urethane-modified polyimide flame-retardant resin composition; a bisphenol-containing polyepoxide adduct was constructed, and it was verified that it has good flame-retardant effect.

[0009] Content of this invention

[0010] The purpose of this invention is to provide a method for preparing and applying a high-temperature resistant, flame-retardant polyimide copolymer epoxy resin.

[0011] To achieve the above-mentioned technical objectives and effects, the invention is implemented through the following technical solution:

[0012] A method for preparing a high-temperature resistant, flame-retardant polyimide copolymer epoxy resin includes the following steps:

[0013] S1. Synthesize chlorobisphenol A aliphatic diamine compounds;

[0014] S2. Synthesize imine chlorobisphenol A aliphatic diamine compounds;

[0015] S3. Preparation of polyimide copolymer bisphenol A epoxy resin based on imine chlorobisphenol A aliphatic diamine compound.

[0016] Furthermore, S1 specifically includes:

[0017] S101, mixed toluene, sodium salt of compound hexachlorobisphenol A, imine chlorobisphenol A aliphatic diamine-chloropropylamine, with zinc acetate as catalyst;

[0018] S102. Under nitrogen protection, heat to 110℃, maintain temperature for 1 hour, cool and filter, wash with water until no sodium chloride is present, wash with ethanol, and dry in an oven at 100℃ to synthesize an imine chlorobisphenol A aliphatic diamine compound.

[0019] Furthermore, the toluene is added in 300 ml of 0.3-0.6 mol of sodium hexachlorobisphenol A, 0.8-1.2 mol of 1-chloropropylamine, and 0.1-0.3 mol of zinc acetate.

[0020] Furthermore, S2 specifically includes:

[0021] S201, mixed toluene, imine chlorobisphenol A fatty diamine;

[0022] S202. Under nitrogen protection, heat to 110℃ and add dropwise a mixture of chlorophthalic anhydride and toluene. After the addition is complete, react for 2 hours, then heat to 120-140℃ and react at a constant temperature for 2-3 hours.

[0023] After the reaction of S203 is completed, the solution turns slightly yellow. After cooling and filtration, the solution is washed with ethanol and dried in an oven at 90-130℃ to synthesize chlorobisphenol A aliphatic diamine compound.

[0024] Further, add 400 ml of toluene, 0.8–1.3 mol of imine chlorobisphenol A fatty diamine, and 0.2–0.7 mol of chlorophthalic anhydride.

[0025] Furthermore, the synthetic route for the chlorobisphenol A aliphatic diamine is as follows:

[0026]

[0027] Among them, chlorobisphenol A aliphatic diamine is heated to obtain propylene oxide-substituted hexachlorobisphenol A (i.e., propylene oxide-substituted hexachlorobisphenol A as indicated in the synthetic route diagram).

[0028] Furthermore, it also includes S3, preparing a chlorinated polyimide chlorinated bisphenol A type epoxy resin coating.

[0029] Furthermore, specifically:

[0030] S301. Add toluene, imine chlorobisphenol A aliphatic diamine and propylene oxide-substituted hexachlorobisphenol A, heat to 150°C under nitrogen protection, and stir slowly for 1-3 hours to generate a viscous prepolymer.

[0031] S302. The prepolymer is coated onto an aluminum plate and placed in a vacuum oven to dry at 60°C for 1-3 hours to prepare imine bisphenol A type epoxy resin.

[0032] Under nitrogen protection, the polymerization reaction is carried out in a drying oven at 160–220°C for 30–90 minutes, followed by natural cooling to obtain a polyimide-modified epoxy resin coating (PIEP).

[0033] Further, add 300 ml of toluene, 0.1–0.9 mol of aminochlorobisphenol A fatty diamine, and 0.9–0.2 mol of propylene oxide-substituted hexachlorobisphenol A.

[0034] Furthermore, polyimide-modified epoxy resin coating (PIEP) is used for flame retardancy.

[0035] Beneficial effects:

[0036] This invention leverages the strong adhesion and corrosion resistance of epoxy resin to prepare a polyimide-co-epoxy resin. The polyimide and epoxy resin are mixed and modified to form a high-temperature resistant polyimide-modified epoxy resin. Compared to existing epoxy resins, this invention solves the problems of poor high-temperature resistance and weather resistance. By using polyimide-co-polymerized bisphenol A epoxy resin, the high-temperature resistance, flame retardancy, and weather resistance of the resin are significantly improved while maintaining strong adhesion and corrosion resistance.

[0037] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0038] Figure 1 This is the 1H-NMR spectrum of the imine chlorobisphenol A aliphatic diamine described in the embodiments of the present invention.

[0039] Figure 2 This is a graph showing the characterization performance test results as described in an embodiment of the present invention. Detailed Implementation

[0040] The preparation method of the high-temperature resistant and flame-retardant polyimide copolymer epoxy resin of the present invention is as follows: Preparation of chlorinated bisphenol A aliphatic diamine

[0041] Add 300 ml of toluene, 0.3–0.6 mol of sodium hexachlorobisphenol A, 0.8–1.2 mol of 1-chloropropylamine, and 0.1–0.3 mol of zinc acetate catalyst to a three-necked flask. Under nitrogen protection, heat to 110 °C and hold at that temperature for 1 hour. Cool and filter, wash with water until no sodium chloride is visible, wash with ethanol, and dry in an oven at 100 °C to obtain chlorobisphenol A aliphatic diamine.

[0042] Preparation of imine chlorobisphenol A aliphatic diamine

[0043] Add 400 ml of toluene and 0.8–1.3 mol of chlorobisphenol A aliphatic diamine to a three-necked flask. Under nitrogen protection, heat to 110 °C, and begin adding 0.2–0.7 mol of a mixture of compound 5 and toluene dropwise. After the addition is complete, allow the reaction to proceed for 2 hours, then raise the temperature to 120–140 °C and maintain the reaction for 2–3 hours. After the reaction is complete, the solution turns slightly yellow. Cool, filter, wash with ethanol, and dry in an oven at 90–130 °C to obtain imine chlorobisphenol A aliphatic diamine.

[0044] The melting point was determined to be 289℃, and the yield was calculated to be 73-86%.

[0045] Nuclear magnetic resonance (NMR) 1 H-NMR was used to test the aliphatic diamine of imine chlorobisphenol A using a Varian Unity Inova-400 NMR spectrometer. 1 1H-NMR spectra were obtained using DMSO-D6 as solvent and tetramethylsilane (TMS) as the internal standard.

[0046] In the imine-chlorobisphenol A aliphatic diamine, δ = 1.5 represents two -NH2 groups, δ = 6.85 and 7.28 represent the ortho and meta positions of the ether bond on the benzene ring of bisphenol A, respectively, δ = 4.04 and 1.98 represent the ortho and meta positions of the ether bond on the straight chain, respectively, and δ = 2.68 represents the ortho position of the imine bond on the straight chain. The spectrum is shown below. Figure 1 As shown.

[0047] This process was then further applied to the preparation of a chlorinated polyimide chlorinated bisphenol A type epoxy resin coating. In a three-necked round-bottom flask, 300 ml of toluene was added, along with 0.1–0.9 mol of imine chlorinated bisphenol A aliphatic diamine and 0.9–0.2 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 150°C and slowly stirred for 1–3 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 60°C for 1–3 hours to prepare the imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized in a drying oven at 160–220°C for 30–90 minutes, followed by natural cooling to obtain a polyimide-modified epoxy resin coating (PIEP).

[0048] Reference for PIEP characterization performance test results Figure 2 Relative average molecular weight and distribution: Agilent 100 high-performance liquid chromatograph, TOSOH gel column, DMF mobile phase, flow rate 1 ml / min, differential refractive index detector, column temperature 40℃. A standard curve was constructed using polystyrene narrow standards to determine the relative average molecular weight and distribution of PIEP.

[0049] The relative number-average molecular weight of the amino acid solution of PIEP, as determined by GPC, is 2.01 × 10⁻⁶. 4 ~9.81×10 4 Between these values, the relative weight-average molecular weight is 4.546 × 10⁻⁶. 4 ~3.98×10 5 The corresponding distribution index D ranges from 2.120 to 5.295, indicating that the copolymerization has reached the high molecular weight polymerization level.

[0050] Glass transition temperature determination: The glass transition temperature of the PIEP coating was determined using a NETZSCH DSC 204 analyzer (Germany) under N2 protection at a heating rate of 10℃ / min.

[0051] For amorphous polymers, the temperature is below the glass transition temperature (T). g When the temperature is above T, the material is as hard as glass. g The material softens over time. Therefore, T g It is the highest service temperature of amorphous polymers. The glass transition temperature mainly depends on two main factors: (1) the flexibility and rigidity of the molecular chain, which depends on the ease of internal rotation; (2) the intermolecular interaction force, which depends on the cohesive energy density. The addition of the flexible segment 1-chloropropylamine can improve the flexibility of the molecular chain, reduce the rigidity of the molecular chain itself and the intermolecular interaction, and reduce the T of polyimide thin and bisphenol A. g This improves the coating's application performance. When the ratio of diamine to bisphenol A is 1:1, the Tg of the copolyimide epoxy coating PIEP is [value missing]. g The lowest temperature was 289.3℃.

[0052] Infrared reflectance characterization: Infrared reflectance spectral analysis was performed on the T / C fabric samples treated with DHDBP using a Nicolet FT-IR 6700 infrared spectrometer.

[0053] Infrared characteristic absorption indicates that on the benzene ring, at 708 cm⁻¹ -1 The characteristic out-of-plane bending absorption peak of monosubstituted benzene ring CH, 3071 cm⁻¹ -l The absorption peak of the CH stretching vibration on the benzene ring is at 1601 cm⁻¹. -l 1583cm -l 1496cm -l 1453cm -l The presence of four finger peaks indicates the existence of a mononuclear aromatic C=C skeleton, thus confirming the presence of a benzene ring.

[0054] Carbonyl absorption peak: at 1689 cm⁻¹ -l A strong absorption peak is present, which is generated by the C=O stretching vibration in the carbonyl group. This peak is observed in the range of 3400–2500 cm⁻¹. -l The region exhibits a broad absorption peak, indicating the stretching vibrations of the OH and NH bonds of all hydroxyl and amine groups in the epoxy resin; 1292 cm⁻¹ -l The characteristic absorption peak for CO stretching is 933 cm⁻¹. -l The characteristic out-of-plane bending absorption peak of OH; 1423 cm⁻¹ -1 The characteristic absorption peak is an in-plane bending absorption peak of OH.

[0055] Mechanical properties of the coating were determined using a CMT4204 microcomputer-controlled electronic universal testing machine (Shenzhen Xin Sansi Metrology Technology Co., Ltd.). The tensile speed was 20 mm / min, the maximum load was 20 kN, and the accuracy class was 0.5. The tensile properties of the PI film were also determined. The film size was 50 mm × 10 mm. The tensile speed was 2 mm / min, and the test was conducted at room temperature.

[0056] Table 1 Tensile shear strength and limiting oxygen index of various modified epoxy coating materials

[0057]

[0058] To more clearly illustrate the technical solution of the present invention, the present invention will be described in detail below with reference to embodiments.

[0059] Example 1

[0060] Preparation of PIEP-21 chlorinated polyimide chlorinated bisphenol A type epoxy resin coating

[0061] 300 ml of toluene was added to a three-necked round-bottom flask, along with 0.6 mol of imine chlorobisphenol A aliphatic diamine and 0.3 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 150 °C and slowly stirred for 3 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 60 °C for 2 hours to prepare an imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized at 190 °C for 70 minutes in a drying oven and then allowed to cool naturally to obtain a polyimide-modified epoxy resin coating (PIEP-21).

[0062] Example 2

[0063] Preparation of PIEP-11 chlorinated polyimide chlorinated bisphenol A type epoxy resin coating

[0064] Toluene (300 ml) was added to a three-necked round-bottom flask, along with 0.5 mol of imine chlorobisphenol A aliphatic diamine and 0.5 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 150°C and slowly stirred for 2 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 60°C for 3 hours to prepare an imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized at 190°C for 80 minutes and then allowed to cool naturally to obtain a polyimide-modified epoxy resin coating (PIEP-11).

[0065] Example 3

[0066] Preparation of PIEP-12 chlorinated polyimide chlorinated bisphenol A type epoxy resin coating

[0067] Toluene (300 ml) was added to a three-necked round-bottom flask, along with 0.3 mol of imine chlorobisphenol A aliphatic diamine and 0.6 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 150°C and slowly stirred for 3 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 70°C for 3 hours to prepare an imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized at 190°C for 90 minutes and then allowed to cool naturally to obtain a polyimide-modified epoxy resin coating (PIEP-12).

[0068] Example 4

[0069] Preparation of PIEP-13 chlorinated polyimide chlorinated bisphenol A type epoxy resin coating

[0070] Toluene (300 ml) was added to a three-necked round-bottom flask, along with 0.25 mol of imine chlorobisphenol A aliphatic diamine and 0.75 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 160°C and slowly stirred for 1.5 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 80°C for 3 hours to prepare an imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized at 220°C for 60 minutes and then allowed to cool naturally to obtain a polyimide-modified epoxy resin coating (PIEP-13).

[0071] Example 5

[0072] Preparation of PIEP-14 chlorinated polyimide chlorinated bisphenol A type epoxy resin coating

[0073] 300 ml of toluene was added to a three-necked round-bottom flask, along with 0.2 mol of imine chlorobisphenol A aliphatic diamine and 0.8 mol of propylene oxide-substituted hexachlorobisphenol A. Under nitrogen protection, the mixture was heated to 165 °C and slowly stirred for 2 hours to generate a viscous prepolymer. The prepolymer was then coated onto an aluminum plate and dried in a vacuum oven at 90 °C for 2 hours to prepare an imine bisphenol A type epoxy resin. Under nitrogen protection, the resin was polymerized at 210 °C for 80 minutes in a drying oven and then allowed to cool naturally to obtain a polyimide-modified epoxy resin coating (PIEP-14).

[0074] The above are merely some of the embodiments of this application and are not intended to limit the application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments shall still fall within the scope of protection of the technical solution of this application.

Claims

1. A method for preparing a high-temperature resistant, flame-retardant polyimide copolymer epoxy resin, characterized in that, Includes the following steps: S1. Synthesize chlorobisphenol A aliphatic diamine compounds; S2. Synthesize imine chlorobisphenol A aliphatic diamine compounds; S3. Preparation of polyimide copolymer bisphenol A epoxy resin based on imine chlorobisphenol A aliphatic diamine compound.

2. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 1, characterized in that, S1 specifically includes: S101, mixed toluene, sodium salt of compound hexachlorobisphenol A, and compound 1-chloropropylamine, with zinc acetate as a catalyst; S102. Under nitrogen protection, heat to 110℃, maintain temperature for 1 hour, cool and filter, wash with water until no sodium chloride is present, wash with ethanol, and dry in an oven at 100℃ to synthesize an imine chlorobisphenol A aliphatic diamine compound.

3. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 2, characterized in that, The toluene is added in 300 ml of water, along with 0.3–0.6 mol of sodium hexachlorobisphenol A, 0.8–1.2 mol of 1-chloropropylamine, and 0.1–0.3 mol of zinc acetate.

4. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 1, characterized in that, S2 specifically includes: S201, mixed toluene, imine chlorobisphenol A fatty diamine; S202. Under nitrogen protection, heat to 110℃ and add dropwise a mixture of chlorophthalic anhydride and toluene. After the addition is complete, react for 2 hours, then heat to 120-140℃ and react at a constant temperature for 2-3 hours. After the reaction of S203 is completed, the solution turns slightly yellow. After cooling and filtration, the solution is washed with ethanol and dried in an oven at 90-130℃ to synthesize chlorobisphenol A aliphatic diamine compound.

5. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 4, characterized in that, Add 400 ml of toluene, 0.8–1.3 mol of imine chlorobisphenol A fatty diamine, and 0.2–0.7 mol of chlorophthalic anhydride.

6. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 5, characterized in that, The synthetic route for the chlorobisphenol A aliphatic diamine is as follows: Among them, chlorobisphenol A fatty diamine is heated to obtain propylene oxide-substituted hexachlorobisphenol A (i.e., compound 6 identified in the synthetic route diagram).

7. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 6, characterized in that, It also includes S3, preparing a chlorinated polyimide chlorinated bisphenol A type epoxy resin coating.

8. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 7, characterized in that, Specifically: S301. Add toluene, imine chlorobisphenol A aliphatic diamine and propylene oxide-substituted hexachlorobisphenol A, heat to 150°C under nitrogen protection, and stir slowly for 1-3 hours to generate a viscous prepolymer. S302. The prepolymer is coated onto an aluminum plate and placed in a vacuum oven to dry at 60°C for 1-3 hours to prepare imine bisphenol A type epoxy resin. Under nitrogen protection, the polymerization reaction is carried out in a drying oven at 160–220°C for 30–90 minutes, followed by natural cooling to obtain a polyimide-modified epoxy resin coating (PIEP).

9. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 8, characterized in that, Add 300 ml of toluene, 0.1–0.9 mol of aminochlorobisphenol A fatty diamine, and 0.9–0.2 mol of propylene oxide-substituted hexachlorobisphenol A.

10. The method for preparing the high-temperature resistant flame-retardant polyimide copolymer epoxy resin according to claim 7, characterized in that, Polyimide-modified epoxy resin coating (PIEP) is used for flame retardancy.

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