Furan resin and preparation method thereof, C / C composite material and thermal field component

Abstract

The invention discloses furan resin and a preparation method thereof, a C / C composite material and a thermal field component. The invention provides furan resin, a C / C composite material and a preparation method thereof, and the preparation method of the furan resin comprises the following steps: esterification reaction: carrying out esterification reaction on phenol and boric acid to obtain a product I; an addition condensation reaction step: carrying out an addition reaction on the product I and an aldehyde compound, and further carrying out a condensation reaction on an obtained intermediate product to obtain a product II; and a polymerization reaction step: carrying out polymerization reaction on the product II and furfuryl alcohol to obtain the furan resin. On one hand, the preparation method can reduce the furfuryl alcohol consumption, improve the resin performance and reduce the manufacturing cost of the furan resin. And on the other hand, the furan resin prepared by the preparation method has high carbon yield and low viscosity, and can be used as a carbon precursor in the preparation process of the C / C composite material to improve the impregnation effect, reduce the impregnation-carbonization times of the C / C composite material, improve the impregnation-carbonization efficiency and shorten the production cycle, thereby reducing the preparation cost of the C / C composite material.

Description

Technical Field

[0001] The present application relates to the technical field of C / C composite materials, and in particular to a furan resin and a preparation method thereof, a C / C composite material and a thermal field component. Background Art

[0002] With the gradual rise of the photovoltaic and semiconductor industries, traditional graphite materials can no longer meet the requirements of high-performance, low-cost, and complex-structured thermal field crucibles, flow guide tubes, insulation tubes and other products.

[0003] C / C composites (Carbon / Carbon composites) are pure carbon multiphase structures composed of carbon fibers or their fabrics as a matrix, reinforced by chemical vapor infiltration of pyrolytic carbon or liquid-phase impregnation-carbonized resin carbon or pitch carbon. These materials are gradually replacing graphite components due to their safety, resistance to cracking under repeated high-temperature thermal vibration, design flexibility, cost-effectiveness, and long product life.

[0004] To meet the high-densification requirements of single crystal furnace thermal fields, the main method used in the related art for preparing C / C composites is chemical vapor infiltration, which results in high production costs. Liquid phase impregnation is also currently used to prepare C / C composites, but the existing carbon precursors are not conducive to high densification of C / C composites, which greatly limits their application in C / C composites.

[0005] Specifically, current carbon precursors for C / C composites, such as benzoxazine resins, phenolic resins, and petroleum asphalt, all have certain drawbacks. Asphalt, due to its complex processing, remains expensive. Phenolic and benzoxazine resins often have viscosities exceeding 200 mPa·s (25°C), hindering the high densification of C / C composites. These factors significantly limit the application of these carbon precursors in C / C composites.

[0006] Furan resin is a low-polymerization polycondensation resin based on furfuryl alcohol and synthesized with formaldehyde, urea, phenol, or acetone. It is a new type of carbon material developed in the 1960s. Its advantages include low viscosity, high strength, resistance to strong acids and bases, high temperature resistance, and simple synthesis process, which largely meet the performance requirements of carbon precursors. However, the main problem with the currently commonly used furan resin in its application is that the residual carbon rate is not high. Taking the furan resin available on the market as an example, under the conditions of air baking in a muffle furnace at 800°C, its residual carbon rate is only about 40% (the main reason is that it is usually prepared from raw materials such as formaldehyde, furfuryl alcohol, urea, acetone or phenol. Under high temperature conditions, the methyl group is easily broken, resulting in the opening of the furan ring, generating a large amount of methane, carbon dioxide, and carbon monoxide, and the residual carbon rate after carbonization is low). If it is used to prepare carbon-carbon composite materials, the number of impregnation-carbonization times of the C / C composite materials will increase, the impregnation carbonization efficiency will be reduced, the production cycle will be extended, and the cost will be increased; in addition, there is also the problem of high viscosity. The viscosity of the current furan resin at 25°C is generally about 500mPa·s, which will make it difficult for the resin to fully penetrate into the pores of the C / C composite material, resulting in uneven impregnation, affecting the density and performance after carbonization.

[0007] Currently, there is no carbon precursor with high carbon residue and low viscosity suitable for preparing C / C composite materials. Summary of the Invention

[0008] To address the problems in the prior art, this application provides a furan resin, a carbon precursor with a high carbon residue, and a method for preparing the same, as well as a carbon / carbon composite material prepared from the furan resin and a carbon fiber preform, and a thermal field component prepared from the C / C composite material. The technical solutions of this application are as follows:

[0009] 1. A furan resin, wherein

[0010] The furan resin comprises a structure

[0011] In the formula, R is independently selected from H or -CH2OH,

[0012] R1 is each independently selected from OH,

[0013] 2. A furan resin, wherein:

[0014] The furan resin is obtained by reacting phenol, boric acid, an aldehyde compound and furfuryl alcohol.

[0015] 3. The furan resin according to claim 2, wherein

[0016] The mass ratio of the phenol, the boric acid, the aldehyde compound, and the furfuryl alcohol is 1:

[0017] (0.167~0.714):(0.167~0.857):(0.5~1.714);

[0018] Preferably, the mass ratio of the phenol to the furfuryl alcohol is 1:(1-1.2).

[0019] 4. The furan resin according to claim 3, wherein

[0020] The furan resin is obtained by reacting phenol, boric acid, a catalyst, an aldehyde compound and furfuryl alcohol; the mass ratio of the phenol, the boric acid, the catalyst, the aldehyde compound and the furfuryl alcohol is 1: (0.167-0.714): (0.017-0.143): (0.167-0.857):

[0021] (0.5~1.714);

[0022] Preferably, the catalyst is sodium hydroxide;

[0023] More preferably, the mass ratio of the phenol to the sodium hydroxide is 1:(0.017-0.030).

[0024] 5. A method for preparing a furan resin, comprising:

[0025] In the esterification reaction step, phenol and boric acid undergo an esterification reaction to obtain product 1;

[0026] an addition condensation reaction step, wherein the product 1 undergoes an addition reaction with an aldehyde compound, and the obtained intermediate product further undergoes a condensation reaction to obtain the product 2;

[0027] In the polymerization step, the second product is polymerized with furfuryl alcohol to obtain the furan resin.

[0028] 6. The preparation method according to item 5, wherein:

[0029] The esterification reaction step comprises: heating and dissolving phenol, adding boric acid, a catalyst, and an organic solvent, heating and reacting, and removing water to obtain the product 1;

[0030] Preferably, the reaction temperature in the esterification reaction step is 120-140° C., and the reaction time is 2-3 h;

[0031] More preferably, the organic solvent is selected from one of toluene, tetrahydrofuran, ethanol, acetone, and n-butanol;

[0032] More preferably, the organic solvent is toluene.

[0033] 7. The preparation method according to item 5, wherein:

[0034] The addition condensation reaction step includes: reacting the product 1 with an aldehyde compound at 90-110° C. for 2-5 hours, removing water, and obtaining the product 2.

[0035] Preferably, the aldehyde compound is paraformaldehyde or formaldehyde;

[0036] More preferably, the aldehyde compound is paraformaldehyde.

[0037] 8. The preparation method according to item 5, wherein:

[0038] The polymerization reaction step comprises: reacting the product 2 with furfuryl alcohol at 90-110° C. for 6-12 hours to obtain the furan resin.

[0039] 9. The preparation method according to item 6, wherein:

[0040] The mass ratio of the phenol, the boric acid, the aldehyde compound, and the furfuryl alcohol is 1:

[0041] (0.167~0.714):(0.167~0.857):(0.5~1.714);

[0042] Preferably, the mass ratio of the phenol, the boric acid, the catalyst, the aldehyde compound, and the furfuryl alcohol is 1:(0.167-0.714):(0.017-0.143):

[0043] (0.167~0.857):(0.5~1.714);

[0044] More preferably, the catalyst is sodium hydroxide;

[0045] Further preferably, the mass ratio of the phenol to the sodium hydroxide is 1:

[0046] (0.017~0.030).

[0047] 10. A C / C composite material, wherein:

[0048] The C / C composite material is prepared using the furan resin described in any one of items 1 and items 2 to 4 or the furan resin prepared by the preparation method of any one of items 5 to 9 and a carbon fiber preform.

[0049] 11. A thermal field component, wherein:

[0050] The thermal field component is prepared by using the C / C composite material described in item 10;

[0051] Preferably, the thermal field components are a crucible, a flow guide tube and a heat preservation tube.

[0052] The method for preparing a carbon precursor furan resin with high carbon residue and the carbon precursor furan resin prepared therefrom provided by the present application, on the one hand, can modify the phenolic furan resin by boric acid to obtain a high-temperature resistant cross-linked structure characterized by a boron ester bond, thereby greatly improving the carbon residue rate of the obtained furan resin; on the other hand, the low viscosity of the furfuryl alcohol resin is utilized to reduce the viscosity of the resin system, so that the viscosity of the finally prepared furan resin is significantly lower than that of the existing furan resin at 25°C, which can improve the impregnation effect during the preparation of the C / C composite material, effectively increase the residual resin carbon after the carbonization process, and fully fill the pores of the preform, thereby reducing the number of impregnation and carbonization times of the C / C composite material, improving the impregnation and carbonization efficiency, shortening the production cycle, and thus reducing costs; furthermore, in the polymerization reaction step, furan and product 2 have a large number of active groups such as -OH groups, so that the two react in a complex manner under acidic conditions, which can reduce the furfuryl alcohol consumption, improve the resin performance, and reduce the manufacturing cost of the furan resin.

[0053] The C / C composite material is prepared by the carbon precursor furan resin and carbon fiber provided in this application; on the one hand, the carbon precursor with high residual carbon can effectively increase the residual resin carbon after the carbonization process, fully fill the pores of the preform, thereby reducing the number of impregnation and carbonization times of the C / C composite material, improving the impregnation and carbonization efficiency, shortening the production cycle, and thus reducing costs. On the other hand, the carbon precursor with low viscosity has good flow properties and fully fills the pores of the preform, thereby generating a dense carbon / carbon composite material, effectively improving the performance of the C / C composite material, shortening the preparation cycle of the C / C composite material, and reducing the production cost of the C / C composite material.

[0054] The above description is only an overview of the technical solution of the present application. In order to make the technical means of the present application clearer and easier to understand, so that those skilled in the art can implement it according to the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are illustrated below. DETAILED DESCRIPTION

[0055] The following embodiments of the present application are intended only to illustrate specific implementation methods for implementing the present application and are not to be construed as limiting the present application. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principles of the present application are deemed equivalent replacements and fall within the scope of protection of the present application.

[0056] This embodiment provides a method for preparing a furan resin, comprising: an esterification reaction step, in which phenol and boric acid undergo an esterification reaction to obtain product one; an addition condensation reaction step, in which product one undergoes an addition reaction with an aldehyde compound, and the obtained intermediate product further undergoes a condensation reaction to obtain product two; and a polymerization reaction step, in which product two undergoes a polymerization reaction with furfuryl alcohol to obtain a furan resin (reddish-brown; in this application, also referred to as modified furan resin or modified BPF / FA resin, wherein B refers to boric acid, PF refers to phenol-formaldehyde, and FA refers to furan).

[0057] In the above technical solution of the present application, on the one hand, in the esterification reaction step, boric acid and phenol are added to modify the phenolic furan resin by boric acid, thereby obtaining a boron ester bond structure with good heat resistance, so that the residual carbon rate of the obtained furan resin is greatly improved (as shown in the following residual carbon rate test results, compared with the existing furan resin, the residual carbon rate under O2 atmosphere is increased by 23.50% to 40.77%, and the residual carbon rate under N2 atmosphere is increased by 6.28% to 17.96%); on the other hand, in the polymerization reaction step, by compounding the boron phenolic resin with the furfuryl alcohol resin, the low viscosity of the furfuryl alcohol resin is utilized to reduce the viscosity of the resin system, so that the viscosity of the finally obtained furan resin at 25°C is significantly reduced (as shown in the following viscosity test results The test results show that the viscosity of the obtained furan resin is only 21.53% to 57.64% of that of the existing furan resin). Those skilled in the art will know that, compared with the existing scheme, the impregnation effect can be improved during the preparation of the C / C composite material, the residual resin carbon after the carbonization process can be effectively increased, and the pores of the preform can be fully filled, thereby reducing the number of impregnation-carbonization times of the C / C composite material, improving the impregnation carbonization efficiency, shortening the production cycle, and thus reducing costs; furthermore, in the polymerization reaction step, furan and the second product have a large number of active groups such as -OH groups, so that the two react in a complex manner under acidic conditions, which can reduce the consumption of furfuryl alcohol, improve the resin performance, and reduce costs (compared with the existing furan resin, the raw material cost can be reduced by 30%).

[0058] Specifically, regarding the esterification reaction step, it includes: heating and dissolving phenol (such as heating to 50-70°C, specifically 50°C, 55°C, 60°C, 65°C or 70°C), adding boric acid, a catalyst, and an organic solvent, heating and reacting, removing water, and obtaining product 1 (a transparent light yellow liquid product). The reaction temperature in the esterification reaction step is 120-140°C (such as 120°C, 123°C, 125°C, 128°C, 130°C, 133°C, 135°C, 138°C or

[0059] 140°C), and the reaction time is 2 to 3 hours (e.g., 2 hours, 2.5 hours, or 3 hours).

[0060] As for the catalyst, it can be sodium hydroxide.

[0061] The organic solvent is one selected from toluene, tetrahydrofuran, ethanol, acetone, and n-butanol. Preferably, the organic solvent is toluene, which can utilize the principle of azeotropic dehydration to avoid reverse hydrolysis of the borate ester, reduce the amount of dehydration by vacuum distillation, avoid reverse hydrolysis of the borate ester, and promote the forward reaction.

[0062] Regarding the addition condensation reaction step, it can include: reacting product one with an aldehyde compound at 90-110°C (specifically 90°C, 95°C, 100°C, 105°C or 110°C) for 2-5h (specifically 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h), removing water to obtain product two (light yellow-green viscous liquid).

[0063] Wherein, the aldehyde compound is paraformaldehyde or formaldehyde. Since the free aldehyde content in the product of the addition condensation reaction step is high when formaldehyde is used, in order to reduce the negative impact on the environment, preferably, the aldehyde compound is paraformaldehyde.

[0064] Polyoxymethylene (POM), also known as polyoxymethylene resin or acetal resin, is a polymer made from formaldehyde monomers with the chemical formula (CH2O). n , wherein n represents the degree of polymerization, and n is generally 8 to 100, which can be used in the above-mentioned reaction of the present application.

[0065] In the addition condensation reaction step, when paraformaldehyde is used as the aldehyde compound, in order to prevent the occurrence of implosion, the paraformaldehyde can be added in batches, for example, the paraformaldehyde can be added in multiple times within 30 minutes.

[0066] Regarding the polymerization reaction step, it can include: reacting product 2 with furfuryl alcohol at 90-110°C (such as 90°C, 95°C, 100°C, 105°C or 110°C) for 6-12h (such as 6h, 7h, 8h, 9h, 10h, 11h, 12h) to obtain a carbon precursor furan resin with high residual carbon.

[0067] In the above reaction, preferably, the mass ratio of phenol, boric acid, catalyst, aldehyde compound, and furfuryl alcohol is 1: (0.167-0.714): (0.017-0.143): (0.167-0.857):

[0068] (0.5~1.714); that is, the mass ratio of phenol, boric acid, catalyst, aldehyde compound and furfuryl alcohol is (35~60):(10~25):(1~5):(10~30):(30~60).

[0069] More preferably, the mass ratio of the phenol to the furfuryl alcohol is 1:(1-1.2);

[0070] Further preferably, the mass ratio of the phenol to the sodium hydroxide is 1:

[0071] (0.017~0.030), at this time, the residual carbon rate of the obtained furan resin is higher.

[0072] Regarding the above-mentioned removal of moisture, specifically, after the reaction and cooling to room temperature, it can be achieved by vacuum distillation. More specifically, excess moisture can be removed under vacuum using a rotary evaporator. Of course, it should be understood that those skilled in the art can select other suitable methods / processes for removing moisture as needed without affecting the purpose of the reaction of the present application.

[0073] Based on the above scheme, in order to ensure sufficient contact and reaction of the substances in each of the above reaction steps, those skilled in the art know that a suitable stirring rate can be set for stirring according to the amount of the substance used, the parameters of the stirring device itself (such as the size of the stirring rod, etc.), etc.

[0074] For the furan resin obtained in the present application, its curing agent can specifically be any one of p-toluenesulfonic acid, xylenesulfonic acid, benzenesulfonic acid, and ethyl sulfate. According to the above preparation method of furan resin, those skilled in the art know that the present application provides a furan resin, wherein it is obtained by reacting phenol, boric acid, aldehyde compound and furfuryl alcohol. Specifically, wherein the mass ratio of the phenol, the boric acid, the aldehyde compound and the furfuryl alcohol is 1: (0.167-0.714):

[0075] (0.167-0.857): (0.5-1.714); that is, the mass ratio of phenol, boric acid, aldehyde compound, and furfuryl alcohol is (35-60): (10-25): (10-30): (30-60). A catalyst may also be included during preparation. In this case, the mass ratio of the phenol, the boric acid, the catalyst, the aldehyde compound, and the furfuryl alcohol is 1: (0.167-0.714): (0.017-0.143):

[0076] (0.167~0.857):(0.5~1.714); that is, the mass ratio of phenol, boric acid, catalyst, aldehyde compound, and furfuryl alcohol is (35~60):(10~25):(1~5):(10~30):

[0077] (30~60).

[0078] The applicant analyzed the principle of the above reaction and combined it with the infrared spectroscopy characterization of the product obtained in this application (the infrared spectroscopy characterization is specifically for the furan resin obtained in the embodiment. The inventor cut the solidified furan resin into small squares of 2 mm in size, placed them in a petri dish and vacuum dried for 24 hours, and then ground the dried resin into powder with a mortar. The VERTEX-70 Fourier transform infrared spectrometer (FTIR) was used with a resolution parameter set to 2 cm -1 , the wave number range is set to 400~4000cm -1 , the number of scans is set to 32 times, and then the scan is started to study the chemical composition of the furan tree), and it can be known that the structure of the furan resin of the present application includes

[0079] In the formula, R is independently selected from H or -CH2OH, R1 is independently selected from OH,

[0080] The borate structure in the aforementioned structure of the present application has high-temperature stability, inhibiting the volatilization of small molecules at high temperatures, thereby increasing the residual carbon rate. Structures such as furfuryl alcohol, due to their low viscosity, act as diluents after compounding. This results in a furan resin with a high residual carbon rate and low viscosity.

[0081] The present application also provides a C / C composite material, which is prepared from the furan resin and carbon fiber preform prepared by the above method. The C / C composite material can be a thermal field component for photovoltaics or semiconductors, for example, it can be a thermal field component in a vertical single crystal furnace, specifically a crucible, a guide tube, an insulation tube, etc. The C / C composite material is obtained by a liquid phase impregnation-carbonization method; first, a preform with a certain porosity is made by weaving, acupuncture and other processes to provide a skeleton for the composite material; then the preform is densified by multiple impregnation-curing-carbonization cycles, specifically, the furan resin is filled into the pores of the preform by vacuum pressure impregnation or normal pressure impregnation, and then the furan resin is cross-linked by high temperature curing to form a three-dimensional network structure; then the cured resin matrix is ​​converted into glassy carbon by carbonization, and combined with carbon fibers to form a C / C blank. Finally, high temperature graphitization, anti-oxidation coating, machining and other post-processing can be carried out according to needs to meet actual needs.

[0082] The furan resin obtained using the above method has a viscosity of less than 200 mPa·s at 25°C and a carbon residue rate of 55% at 800°C in air. This allows the prepared C / C composite to have high density, which can greatly promote the application of C / C composites in photovoltaics and semiconductors.

[0083] The present application also provides a thermal field component, which is prepared by adopting the above method to obtain a C / C composite material; the thermal field component provided by the present application has high density.

[0084] Preferably, the thermal field components are crucibles, flow guides, and insulation tubes. Crucibles, flow guides, and insulation tubes are core thermal field components in Czochralski silicon production. The thermal field components provided in this application are highly compact and low-cost, and can be applied in large quantities in Czochralski silicon production.

[0085] Example

[0086] Unless otherwise specified, the experimental methods used below are conventional methods.

[0087] Unless otherwise specified, the materials and reagents used below can be obtained from commercial sources.

[0088] Example 1:

[0089] Step 1: Heat 47 g of phenol to 65°C to dissolve, add 20 g of boric acid, 1.034 g of NaOH (catalyst), and 45 ml of toluene (organic solvent), and heat to 125°C for 3 h. After the reaction is complete, cool to room temperature and use a rotary evaporator to react at 75°C for 1 h to remove excess water to obtain a transparent light yellow liquid product 1;

[0090] Step 2: Product 1 and 22.5 g of paraformaldehyde (aldehyde compound; Aladdin, product number C104188, chemical registration number 30525-89-4) were added in sequence and reacted at 105° C. for 2.5 h. The liquid changed from yellow turbidity to a light yellow-green solution. Excess water was removed by rotary evaporation at 75° C. for 1 h to obtain a light yellow-green viscous liquid product 2.

[0091] Step 3: Product 2 and 49 g of furfuryl alcohol were added in sequence and reacted at 105° C. for 8 h to obtain a reddish-brown product 3, which is a high carbon residue modified furan resin.

[0092] The difference between Examples 2 to 4 and Comparative Examples 1 to 4 and Example 1 is only that the reaction conditions (reaction temperature, reaction time) of each step are different. The specific reaction conditions are shown in Table 1.

[0093] Table 1: Reaction conditions of Examples 1 to 4 and Comparative Examples 1 to 4

[0094]

[0095]

[0096] Comparing the resin obtained in the comparative example with that in the examples, it can be seen that the experimental steps of the comparative example and the examples are basically the same, except that the reaction time and reaction temperature of each step are different.

[0097] During the experiments of Comparative Examples 1 and 2, a large amount of precipitate was formed in the product obtained in step 1. IR analysis showed that the product contained a large amount of unreacted boric acid, and no subsequent experiments or tests were performed.

[0098] During the experiment of Comparative Example 3, the solution in step 2 changed from light yellow to light yellow-green, but the product was mixed with white viscous particles. After analysis, it was found to be incompletely reacted paraformaldehyde, and no subsequent experiments and tests were performed.

[0099] During the experimental process of Comparative Example 4, the product solution of step 3 changed from light yellow to reddish brown, but was mixed with a small amount of precipitate and therefore could not be used for subsequent experiments and detection.

[0100] The products obtained in Examples 1 to 4 did not exhibit the above-mentioned problem, and a clear reddish-brown furan resin was successfully prepared and used for subsequent testing.

[0101] The difference between Examples 5 to 9 and Comparative Examples 5 to 9 and Example 1 is only the following added substances and amounts. See Table 2 for details.

[0102] Table 2: Added substances and their amounts in Examples 5 to 9 and Comparative Examples 5 to 9

[0103]

[0104]

[0105] Comparative Examples 5 to 7 correspond to Example 1 and have essentially the same steps, except that in step 1, aqueous ammonia is used as the catalyst. Since aqueous ammonia is a weak base, its catalytic effect in step 1 is weak, and the product undergoes emulsification and stratification upon standing, preventing further synthesis. NaOH, on the other hand, has a strong catalytic effect on the hydroxymethylation reaction of phenol, yielding product 1 with a high hydroxymethyl content. Therefore, NaOH is the most effective catalyst.

[0106] In Comparative Example 9, stratification occurred during the experiment, and subsequent experiments and tests could not be performed.

[0107] The furan resins obtained in Examples 5 to 9 and Comparative Example 8 were used for testing in subsequent test examples.

[0108] Test example

[0109] 1. Resin viscosity determination

[0110] As described above, the furan resins obtained in Examples 1 to 9 and Comparative Example 8 were selected for resin viscosity measurement. In addition, as a comparison, the same test was performed on an existing commercial furan resin (Shengquan Company, Model: FAR-100, as Comparative Example 10).

[0111] The viscosity of furan resin was measured using an SNB-1 rotary viscometer. The resin sample temperature was maintained at 25 ± 0.5°C in a constant-temperature water bath. Before testing, an appropriate spindle was selected so that each reading was within the 20% to 80% range of the scale. During testing, the spindle was vertically immersed in the resin sample, and readings were taken only after the pointer stabilized on the scale. Three parallel tests were performed for each resin sample, and the average value was taken as the viscosity value of the resin sample.

[0112] Table 3: Viscosity test results

[0113]

[0114] The above test results show that compared with the furan resin of the existing solution (Comparative Example 10), the viscosity of the furan resin obtained by the technical solution of the present application (Examples 1 to 9) is within 200 mPa·s, which is only 21.53% to 57.64% of the furan resin of the existing solution (Comparative Example 10) (especially Example 1, which is only 21.53% of Comparative Example 10), greatly reducing the viscosity of the furan resin. Those skilled in the art know that the lower the viscosity of the furan resin, the better the impregnation effect during the preparation of the C / C composite material, which can effectively increase the residual resin carbon after the carbonization process and fully fill the pores of the preform, thereby reducing the number of impregnation-carbonization times of the C / C composite material, improving the impregnation carbonization efficiency, shortening the production cycle, and thus reducing costs.

[0115] In addition, the applicant conducted a storage stability test on the furan resin obtained in Example 1. After being stored at room temperature for 30 days, the viscosity test showed that the viscosity change at 25° C. was less than 5%, which can be considered as no significant change.

[0116] 2. Carbon residue rate detection

[0117] The furan resins obtained in Example 1 (Example 1 is selected as a representative among Examples 1 to 4), Examples 5 to 9, and Comparative Example 8, as well as the above-mentioned existing furan resin (Comparative Example 10), were subjected to the following tests.

[0118] (1) Weigh 4 g of furan resin and different contents of p-toluenesulfonic acid curing agent in a paper cup, stir for 30 seconds, and then place in a mold;

[0119] (2) Curing in an oven at 100°C and recording the curing time;

[0120] (3) Weigh 2 g of the cured resin and bake it in a muffle furnace at 800 °C under O2 and N2 atmospheres, respectively. Record the mass change and output the residual carbon rate.

[0121] Table 4: Carbon residue rate test results

[0122]

[0123]

[0124] Note: The above curing agent content and residual carbon rate refer to mass percentage.

[0125] The above results show that within the commonly used curing agent content range (0.3% to 1%), the carbon residue rate of the furan resin obtained in the present embodiment of the present application under an O2 atmosphere increased by 23.50% to 40.77%, and the carbon residue rate of the furan resin obtained in the present embodiment of the present application under an N2 atmosphere increased by 6.28% to 17.96%. In particular, the furan resin of Example 1 above increased its carbon residue rate by 37.86% to 40.78% under an O2 atmosphere and by 16.64% to 17.96% under an N2 atmosphere. This is mainly because toluene acts as a dehydrating agent, preventing the reverse hydrolysis of the boric acid ester, thereby promoting the forward reaction, resulting in the highest carbon residue rate. Compared with the furan resin obtained in the present embodiment of the present application, the carbon residue rate of the furan resin obtained in Comparative Example 8 is relatively low.

[0126] Although the embodiments of the present application are described above, the present application is not limited to the above-mentioned specific embodiments and application fields. The above-mentioned specific embodiments are merely illustrative and instructive, and not restrictive. A person of ordinary skill in the art, guided by this specification and without departing from the scope of protection of the claims of this application, may also devise various forms, all of which fall within the scope of protection claimed in this application.

Claims

1. A furan resin, wherein The furan resin comprises a structure In the formula, R is independently selected from H or -CH2OH, R1 is each independently selected from OH, 2. A furan resin, wherein The furan resin is obtained by reacting phenol, boric acid, an aldehyde compound and furfuryl alcohol.

3. The furan resin according to claim 2, wherein The mass ratio of the phenol, the boric acid, the aldehyde compound, and the furfuryl alcohol is 1: (0.167～0.714)：(0.167～0.857)：(0.5～1.714)； Preferably, the mass ratio of the phenol to the furfuryl alcohol is 1:(1-1.2).

4. The furan resin according to claim 3, wherein The furan resin is obtained by reacting phenol, boric acid, a catalyst, an aldehyde compound and furfuryl alcohol; the mass ratio of the phenol, the boric acid, the catalyst, the aldehyde compound and the furfuryl alcohol is 1: (0.167-0.714): (0.017-0.143): (0.167-0.857): (0.5～1.714)； Preferably, the catalyst is sodium hydroxide; More preferably, the mass ratio of the phenol to the sodium hydroxide is 1:(0.017-0.030).

5. A method for preparing a furan resin, wherein: include: In the esterification reaction step, phenol and boric acid undergo an esterification reaction to obtain product 1; an addition condensation reaction step, wherein the product 1 undergoes an addition reaction with an aldehyde compound, and the obtained intermediate product further undergoes a condensation reaction to obtain the product 2; In the polymerization step, the second product is polymerized with furfuryl alcohol to obtain the furan resin.

6. The preparation method according to claim 5, wherein The esterification reaction step comprises: heating and dissolving phenol, adding boric acid, a catalyst, and an organic solvent, heating and reacting, and removing water to obtain the product 1; Preferably, the reaction temperature in the esterification reaction step is 120-140° C., and the reaction time is 2-3 h; More preferably, the organic solvent is selected from one of toluene, tetrahydrofuran, ethanol, acetone, and n-butanol; More preferably, the organic solvent is toluene.

7. The preparation method according to claim 6, wherein The addition condensation reaction step includes: reacting the product 1 with an aldehyde compound at 90-110° C. for 2-5 hours, removing water, and obtaining the product 2; Preferably, the aldehyde compound is paraformaldehyde or formaldehyde; More preferably, the aldehyde compound is paraformaldehyde.

8. The preparation method according to claim 7, wherein The polymerization reaction step comprises: reacting the product 2 with furfuryl alcohol at 90-110° C. for 6-12 hours to obtain the furan resin.

9. The preparation method according to claim 8, wherein The mass ratio of the phenol, the boric acid, the aldehyde compound, and the furfuryl alcohol is 1: (0.167～0.714)：(0.167～0.857)：(0.5～1.714)； Preferably, the mass ratio of the phenol, the boric acid, the catalyst, the aldehyde compound, and the furfuryl alcohol is 1:(0.167-0.714):(0.017-0.143): (0.167～0.857)：(0.5～1.714)； More preferably, the catalyst is sodium hydroxide; Further preferably, the mass ratio of the phenol to the sodium hydroxide is 1: (0.017～0.030)。 10. A C / C composite material, wherein: The C / C composite material is prepared using the furan resin according to any one of claims 1 and claims 2 to 4 or the furan resin prepared by the preparation method of any one of claims 5 to 9 and a carbon fiber preform.

11. A thermal field component, wherein: The thermal field component is prepared by using the C / C composite material according to claim 10; Preferably, the thermal field components are a crucible, a flow guide tube and a heat preservation tube.

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