Preparation method of ceramic boron-phenolic aldehyde composite resin

Abstract

The invention relates to a preparation method of ceramic boron-phenolic composite resin, and aims to solve the problems of poor mechanical property, reduced heat resistance and the like of the existing phenolic resin material. The preparation method comprises the following steps: 1, dissolving boron phenolic resin in absolute ethyl alcohol under a heating condition; 2, adding a mixed filler into the resin solution under a water bath heating condition, wherein the mixed filler is prepared from calcined kaolin, aluminum oxide, low-melting-point glass powder, diboron trioxide and zirconium diboride; 3, carrying out pre-curing treatment; 4, performing vacuum curing treatment; and 5, final curing treatment. By screening and designing the ceramic forming agent components and determining the optimal ratio of the ceramic forming agent components, the mechanical property of the boron phenolic resin laminated board is remarkably enhanced, the heat resistance and the mechanical property are remarkably improved, the synergistic effect of the ceramic matrix and the ceramic forming agent is utilized, a filler system is constructed, and the service life of the boron phenolic resin laminated board is prolonged. And efficient ceramic conversion of the material in combustion and high-temperature extreme environments is ensured, so that the composite material is endowed with excellent ablation resistance and high-temperature stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramicizable composite materials, and particularly relates to a preparation method and application of a boron phenolic resin composite material. Background Art

[0002] Phenolic resin plays an indispensable role in modern industry. It is a large class of synthetic resins obtained by the addition and condensation reactions of phenolic compounds such as phenol, cresol, xylenol, resorcinol, etc. and aldehyde compounds such as formaldehyde, furfural, etc. under acidic or alkaline conditions. However, the molecular structure contains some ether bonds and methylene bonds, which are easily oxidized, leading to a decrease in the heat resistance of the resin. And the biggest drawback of the cured phenolic resin is its large brittleness and poor mechanical properties. With the improvement of the performance requirements for phenolic resin, ordinary phenolic resin has been difficult to meet the requirements of many high-tech fields.

[0003] Ceramicizable materials are a cost-effective choice for heat-resistant protection materials because of their ablation resistance, high temperature resistance, and ability to form a ceramic support to maintain their structure. Ceramicizable materials generally use polymers as the matrix, adding ceramic-forming fillers and fluxes and other auxiliary components, which act synergistically under high-temperature conditions to undergo a crystallization reaction to form a ceramic-like protective layer, playing a role in flame retardancy and heat insulation while building a self-supporting system to improve structural stability. However, the performance of ceramicizable materials may not be satisfactory before reaching the ceramicization temperature, and the excessively high ceramicization temperature makes it difficult to ensure the material properties at room temperature, and the high cost of nano-ceramic fillers and ceramic-forming fillers such as titanium and zirconium makes it difficult to put ceramicizable materials into actual production. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a ceramicizable boron phenolic composite resin to solve the problems of poor mechanical properties and decreased heat resistance of existing phenolic resin materials.

[0005] The preparation method of the ceramicizable boron phenolic composite resin of the present invention is realized according to the following steps:

[0006] I. Dissolution of boron phenolic resin:

[0007] Dissolve boron phenolic resin (BPR) in absolute ethanol under heating conditions to form a uniform resin solution;

[0008] II. Addition and mixing of raw materials:

[0009] Add mixed fillers to the resin solution under water bath heating conditions and stir ultrasonically to obtain a composite material solution;

[0010] III. Pre-curing treatment:

[0011] Heat the composite material solution to 75 - 85 °C for pre - curing treatment to obtain a pre - cured composite material solution;

[0012] IV. Vacuum curing treatment:

[0013] Heat the pre - cured composite material solution to 110 - 130 °C, evacuate to carry out vacuum curing treatment to obtain a vacuum - cured composite material;

[0014] V. Final curing treatment:

[0015] Heat the vacuum - cured composite material to 140 - 160 °C for final curing treatment to obtain a ceramizable boron - phenolic composite resin;

[0016] The mixed filler in step II consists of calcined kaolin, alumina, low - melting - point glass powder, boron trioxide and zirconium diboride. The mass ratio of calcined kaolin, alumina and low - melting - point glass powder is 4:4:1.

[0017] In the preparation method of the ceramizable boron - phenolic composite resin of the present invention, the filler consists of calcined kaolin, alumina, low - melting - point glass powder, boron trioxide and zirconium diboride. At temperatures below the porcelain - forming temperature, Al2O3 acts as a ceramic matrix to support the composite material, improving the heat - resistance of the boron - phenolic resin material before porcelain - formation; at high temperatures, kaolin and ZrB2 react under the combined action of glass powder and B2O3 to form a eutectic ceramic phase, and the material is ceramized at high temperatures, providing a flame - retardant and heat - insulating effect for the composite material and building a self - supporting system to improve the structural stability.

[0018] The preparation method of the ceramizable boron - phenolic composite resin of the present invention has the following beneficial effects:

[0019] 1. By screening and designing the components of the porcelain - forming agent and determining its optimal ratio, the mechanical properties of the boron - phenolic resin laminate are significantly enhanced, achieving a remarkable improvement in heat - resistance and mechanical properties;

[0020] 2. By utilizing the synergistic effect of the ceramic matrix and the porcelain - forming agent, a filler system is constructed to ensure the efficient ceramic conversion of the material in extreme environments such as combustion and high temperatures, thereby endowing the composite material with excellent ablation - resistance characteristics and high - temperature stability;

[0021] 3. By using widely available industrial - grade porcelain - forming fillers as the core components, with kaolin, Al2O3 and glass powder in the porcelain - forming fillers accounting for 85%, the preparation cost of the composite material is effectively reduced, achieving a dual improvement in economic benefits and high performance. Description of the Drawings

[0022] Figure 1 XRD pattern of the ceramizable boron - phenolic composite resin prepared in Example 1;

[0023] Figure 2 Photograph of the ceramizable boron phenolic composite resin prepared in Example 1 after being burned by a butane flame;

[0024] Figure 3 Flame retardancy test chart of the ceramizable boron phenolic composite resin prepared in Example 1. Detailed implementation manners

[0025] Detailed implementation manner 1: The preparation method of the ceramizable boron phenolic composite resin in this implementation manner is carried out according to the following steps:

[0026] I. Dissolution of boron phenolic resin:

[0027] Dissolve boron phenolic resin (BPR) in absolute ethanol under heating conditions to form a uniform resin solution;

[0028] II. Addition and mixing of raw materials:

[0029] Add mixed fillers to the resin solution under water bath heating conditions and stir ultrasonically to obtain a composite material solution;

[0030] III. Pre-curing treatment:

[0031] Heat the composite material solution to 75 - 85 °C for pre-curing treatment to obtain a pre-cured composite material solution;

[0032] IV. Vacuum curing treatment:

[0033] Raise the temperature of the pre-cured composite material solution to 110 - 130 °C and carry out vacuum curing treatment by pumping vacuum to obtain a vacuum-cured composite material;

[0034] V. Final curing treatment:

[0035] Raise the temperature of the vacuum-cured composite material to 140 - 160 °C for final curing treatment to obtain a ceramizable boron phenolic composite resin;

[0036] Among them, the mixed fillers in step II are composed of calcined kaolin (A), alumina (B), low-melting glass powder (C), boron trioxide (D) and zirconium diboride (E), and the mass ratio of calcined kaolin, alumina and low-melting glass powder is 4:4:1.

[0037] The composite material solution in step II of this implementation manner can also be coated on a support such as a fiber cloth.

[0038] In this implementation manner, the ratio of calcined kaolin:Al2O3:glass powder is optimized to 4:4:1 to improve the mechanical properties of the boron phenolic resin material.

[0039] Embodiment 2: The difference between this embodiment and Embodiment 1 is that in Step 1, boron phenolic resin (BPR) is dissolved in absolute ethanol under the condition of heating to 50°C.

[0040] Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that in Step 2, the water bath heating temperature is 50°C.

[0041] Embodiment 4: The difference between this embodiment and any one of Embodiments 1 to 3 is that in Step 2, the ultrasonic stirring time is 20 to 50 minutes.

[0042] Embodiment 5: The difference between this embodiment and any one of Embodiments 1 to 4 is that in Step 2, the mass ratio of boron phenolic resin to the mixed filler is (0.8 to 1.2):(0.8 to 1.2).

[0043] Embodiment 6: The difference between this embodiment and any one of Embodiments 1 to 5 is that in Step 2, the mass ratio of calcined kaolin, alumina, low melting point glass powder, boron trioxide and zirconium diboride is 4:4:1:0.5:1.

[0044] Embodiment 7: The difference between this embodiment and Embodiment 6 is that the melting point of the low melting point glass powder is 320 to 350°C.

[0045] Embodiment 8: The difference between this embodiment and any one of Embodiments 1 to 7 is that in Step 3, the pre-curing treatment time is 20 to 40 minutes.

[0046] Embodiment 9: The difference between this embodiment and any one of Embodiments 1 to 8 is that in Step 3, the vacuum curing treatment time is 50 to 80 minutes.

[0047] Embodiment 10: The difference between this embodiment and any one of Embodiments 1 to 9 is that the final curing treatment time is 50 to 80 minutes.

[0048] Example 1: The preparation method of the ceramizable boron phenolic composite resin in this example is implemented according to the following steps:

[0049] I. Dissolution of boron phenolic resin:

[0050] Under the condition of heating to 50°C, boron phenolic resin (BPR) is dissolved in absolute ethanol according to a mass ratio of 1:1.2 to form a uniform resin solution;

[0051] II. Addition and mixing of raw materials:

[0052] Under the condition of water bath heating at 50°C, the mixed filler is added to the resin solution. The mass ratio of the mixed filler to the boron phenolic resin is 1:1, and ultrasonic stirring is carried out for 30 min to obtain a composite material solution;

[0053] III. Pre-curing treatment:

[0054] Heat the composite material solution to 80 °C for pre-curing treatment for 30 min to obtain a pre-cured composite material solution;

[0055] IV. Vacuum curing treatment:

[0056] Heat the pre-cured composite material solution to 120 °C, evacuate to carry out vacuum curing treatment for 1 h to obtain the composite material after vacuum curing;

[0057] V. Final curing treatment:

[0058] Heat the composite material after vacuum curing to 150 °C for final curing treatment for 1 h to obtain a ceramizable boron phenolic composite resin;

[0059] Among them, the mixed filler in step II is composed of calcined kaolin (A), alumina (B), low-melting glass powder (C), boron trioxide (D) and zirconium diboride (E) with a mass ratio of 4:4:1:0.5:1, and the melting point of the low-melting glass powder is 330 °C.

[0060] In step II of this embodiment, the composite material solution is coated on a glass fiber cloth (GF), and placed in a hot press to obtain a laminate by using the same curing process as in steps III to V, and subsequent high-temperature performance tests are carried out through the laminate.

[0061] The differences between Comparative Examples 1-5 and Example 1 are only in the mixing ratio of the mixed filler. The mixing ratios of the mixed filler in Comparative Examples 1-5 and Example 1 are shown in Table 1 below.

[0062] Table 1

[0063] Test item Component Example 1 BPR / ABCDE Comparative Example 1 BPR Comparative Example 2 BPR / AC Comparative Example 3 BPR / A:B:C = 4.5:4.5:1 Comparative Example 4 BPR / A:B:C = 7:2:1 Comparative Example 5 BPR / A:B:C = 2:7:1

[0064] Perform performance tests on the ceramizable laminates of the boron phenolic resins in Example 1 and Comparative Examples 1-5, and the test results are shown in Table 2 below.

[0065] Table 2 Test results of the application of ceramizable composites of boron phenolic resins to laminates

[0066]

[0067]

[0068] Among them, the flexural strength, maximum flexural force, and the three-point bending performance of the GF-filler / BPR laminate were tested according to the GB / T 1449-2005 standard. The specimen size was 100 mm × 15 mm × 1 mm. The test results were expressed as the average value of five specimens. The instrument was a microcomputer-controlled electronic universal testing machine RGT-20A, manufactured by Shenzhen Regal Instrument Co., Ltd.

[0069] As can be seen from Table 2:

[0070] a) Adding a single ceramizing agent in Comparative Example 2 would slightly reduce the flexural strength of the boron phenolic resin composite material. Simply reducing the resin content could not directly improve the mechanical properties. After adding Al2O3 to the boron phenolic resin composite materials in Comparative Examples 3-5, as a ceramic-like matrix, it improved the flexural strength of the composite material at room temperature. The flexural strength of the composite laminate with the optimal compounding ratio could reach 287.37 MPa.

[0071] b) Compared with Comparative Example 1, in Example 1, the composite material with the optimal compounding ratio was added with boride fillers, and the mechanical properties modified by the fillers were significantly improved. The flexural strength reached 291.39 MPa, and the maximum flexural force could reach 38.55 N, which were increased by 94.49% and 616.54% respectively. While ensuring the ceramizable function of the boron phenolic resin composite material, the mechanical properties were significantly improved.

[0072] The performance tests were carried out on the ceramizable boron phenolic resin composite materials and their laminates of Example 1 and Comparative Examples 1-5, and the test results are shown in Table 3 below.

[0073] Table 3 Test results of the high-temperature resistance of the ceramizable boron phenolic resin composite materials and their laminates

[0074]

[0075] Among them, the char residue rate: Take 2 g of the filler / BPR composite resin powder and place it in a tube furnace at room temperature. Heat it to 800 °C at a rate of 10 °C / min and hold for 30 min. After cooling to room temperature, weigh it to calculate the residue rate;

[0076] Thermal insulation performance: Vertically fix the GF-filler / BPR laminate with a size of 50 mm × 50 mm on an iron clamp, and use a butane flame (900-1000 °C) for vertical ablation for 300 s. The distance between the flame and the laminate is 10 cm. Record the ablation area and the temperature difference between the front and back sides.

[0077] a) In Comparative Examples 1-5, the residue rates of the boron phenolic resin composite at 800 °C and 1000 °C were improved to varying degrees after adding the porcelain-forming agent and the fluxing agent. There was more residual carbon at higher temperatures, and the porcelain-forming effect was better. After adding Al2O3 to the composite material, the residue rate showed varying degrees of fluctuation. Overall, it was shown that calcined kaolin and Al2O3 synergistically enhanced the degree of ceramization. Among them, in Comparative Example 4, the content of calcined kaolin was higher, and the degree of ceramization was higher. The residual carbon rates at 800 °C and 1000 °C reached 74.34% and 67.47% respectively.

[0078] b) In Example 1, the melting points of the low-melting glass powder and B2O3 added to the boron phenolic resin composite were both lower than 500 °C. They synergistically assisted in melting under high-temperature conditions to help form the support while increasing the degree of porcelain formation at the same temperature. The residual carbon rates at 800 °C and 1000 °C reached 76.34% and 77.50% respectively, which were 22.40% and 35.56% higher than those in Comparative Example 1 at the same temperature, and 2.69% and 14.87% higher than those in Comparative Example 4 at the same temperature.

[0079] c) In Example 1, the ZrB2 added to the boron phenolic resin composite had a high hardness. While maintaining the mechanical properties of the preferred ratio, zirconium oxide generated at high temperatures had a higher melting point and heat resistance. It formed a flame-retardant and ablation-resistant eutectic with kaolin and Al2O3 to jointly form porcelain, improving the residual carbon and heat insulation performance at high temperatures. The thermal conductivity of the composite material at room temperature could reach 0.528 W / mK, which was 21.10% higher than that in Comparative Example 1. Under the ablation of a butane flame, it could quickly conduct and disperse the concentrated heat, improving the heat insulation performance of the laminate.

[0080] It can be seen from the XRD analysis of Example 1 that Al2O3 maintained a good crystal form at 800 °C - 1000 °C and provided good heat resistance for the composite material as a ceramic matrix under high-temperature conditions; at 1000 - 1200 °C, Si mainly existed in the form of crystals such as cristobalite and moissanite, and boride reacted with kaolin at high temperatures to generate Al 18 B4O 33 As a reinforcing material for ceramics, it provided excellent heat resistance and flame retardancy;

[0081] From Figure 2 it can be seen that after the ceramizable boron phenolic composite resin obtained in Example 1 was burned by a butane flame, it quickly transferred and dispersed the high temperature on the surface. The central flame generated a ceramic phase at high temperature to improve the heat insulation ability and prevent the spread of the flame.

[0082] From Figure 3It can be seen that the ceramizable boron phenolic composite resin obtained in Example 1 is ignited at an oxygen concentration of 85%, extinguishes after 5 s of flameless combustion, the combustion does not exceed 10 mm, and a ceramic phase is rapidly formed at the ignited part to prevent combustion. Through the limiting oxygen test, this boron phenolic resin composite material has excellent flame retardant properties.

Claims

1. A preparation method of a ceramifiable boron phenolic composite resin, characterized in that The preparation method of the ceramizable boron phenolic resin is realized according to the following steps: I. Dissolution of boron phenolic resin: Dissolve the boron phenolic resin in absolute ethanol under heating conditions to form a uniform resin solution; II. Addition and mixing of raw materials: Add the mixed filler to the resin solution under water bath heating conditions and stir ultrasonically to obtain a composite material solution; III. Pre-curing treatment: Heat the composite material solution to 75 - 85 °C for pre-curing treatment to obtain a pre-cured composite material solution; IV. Vacuum curing treatment: Raise the temperature of the pre-cured composite material solution to 110 - 130 °C, evacuate to carry out vacuum curing treatment to obtain a vacuum-cured composite material; V. Final curing treatment: Raise the temperature of the vacuum-cured composite material to 140 - 160 °C for final curing treatment to obtain the ceramizable boron phenolic resin; Among them, the mixed filler in step II is composed of calcined kaolin, alumina, low-melting-point glass powder, boron trioxide and zirconium diboride, and the mass ratio of calcined kaolin, alumina and low-melting-point glass powder is 4:4:

1.

2. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, wherein In step I, the boron phenolic resin is dissolved in absolute ethanol under the condition of heating to 50 °C.

3. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, characterized in that In step II, the water bath heating temperature is 50 °C.

4. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, characterized in that In step II, the ultrasonic stirring time is 20 - 50 minutes.

5. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, wherein In step II, the mass ratio of boron phenolic resin to mixed filler is (0.8 - 1.2):(0.8 - 1.2).

6. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, characterized in that In step II, the mass ratio of calcined kaolin, alumina, low-melting-point glass powder, boron trioxide and zirconium diboride is 4:4:1:0.5:

1.

7. The preparation method of the ceramifiable boron phenolic composite resin according to claim 6, characterized in that The melting point of the said low-melting-point glass powder is 320 - 350 °C.

8. The preparation method of the ceramizable boron phenolic composite resin according to claim 1, characterized in that In step III, the pre-curing treatment time is 20 - 40 minutes.

9. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, characterized in that In step III, the vacuum curing treatment time is 50 - 80 minutes.

10. The preparation method of the ceramifiable boron phenolic composite resin according to claim 1, characterized in that The final curing treatment time is 50 - 80 minutes.

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