CN109133959B

CN109133959B - A kind of carbon fiber rigid heat insulation tile and preparation method thereof

Info

Publication number: CN109133959B
Application number: CN201811061423.9A
Authority: CN
Inventors: 鲁胜; 吴宪; 张凡; 郭慧; 赵英民
Original assignee: Aerospace Research Institute of Materials and Processing Technology
Current assignee: Aerospace Research Institute of Materials and Processing Technology
Priority date: 2016-12-02
Filing date: 2016-12-02
Publication date: 2021-05-07
Anticipated expiration: 2036-12-02
Also published as: CN109133959A; CN106747267A; CN106747267B

Abstract

The invention relates to a carbon fiber rigid heat insulation tile, which comprises chopped carbon fibers constituting a skeleton, and a Si/C/O glass bonding phase for bonding the chopped carbon fibers. The invention also provides a preparation method of the carbon fiber rigid heat insulation tile. The present invention uses silicone resin to prepare the bonding phase between carbon fibers, generates Si/C/O glass bonding phase during carbonization and cracking, and plays the role of bonding chopped carbon fiber skeleton. After the phase is oxidized in a high-temperature aerobic environment, a layer of silica glass film will be formed on the surface, thereby preventing the oxygen atoms from further oxidizing the internal substances, so it has strong oxidation resistance, and the residual silicone resin is cracked in an inert atmosphere. The carbon ratio is high, and the mechanical strength is also higher compared to using starch as a binder.

Description

Carbon fiber rigid heat insulation tile and preparation method thereof

The application is a divisional application entitled "carbon fiber rigid heat insulation tile and preparation method thereof", and the application date of the original application is 2016.12.2, and the application number is 201611100591.5.

Technical Field

The invention relates to the technical field of functional composite materials, in particular to a carbon fiber rigid heat insulation tile and a preparation method thereof.

Background

The carbon fiber rigid heat insulation tile has the advantages of high temperature resistance, light weight, porosity, good heat insulation effect and the like, can be directly used as an ultrahigh temperature heat insulation material, and can also be used as a raw material for preparing a light ablation material or an antioxidant carbon-based ceramic composite material through composite resin.

The united states atomic energy commission disclosed a method of making fibrous insulation material in U.S. patent No. 3577344. According to the patent, oxide ceramic fibers such as chopped carbon fibers, quartz fibers or aluminum silicate and the like are used as raw materials, soluble starch is used as an adhesive, a corresponding fiber heat-insulating material blank is prepared through a wet forming process, and the starch after gelatinization polymerization is cracked in a high-temperature furnace to form an adhesive carbon phase. The fiber heat-insulating material is used for high-temperature thermal protection in the field of nuclear power. Because the fiber heat-insulating material uses soluble starch as the adhesive, the residual carbon rate of the polymerized starch after cracking in a high-temperature furnace is low, and the mechanical strength of the prepared carbon fiber rigid heat-insulating tile is insufficient.

An improvement in the process of making the above-mentioned light-weight fibrous insulation material of U.S. patent No. 3577344 is disclosed in U.S. patent No. 4152482, published by the U.S. department of energy. Us patent 4152482 eliminates the stress build-up in the fiber matrix when the binder phase resin cures by a layered filtration, layered cure process. In addition, the layered filtering process enables the structure of the light fiber heat-insulating material to be more controllable, and gradient change of product performance can be realized by using different fiber matrixes, high-emissivity fillers and the like in different layers. Fiber Materials Incorporation (FMI) manufactured by U.S. Fiber Materials corporation under a trade designation

The carbon fiber light rigid heat insulation tile. Chopping carbon fiber with diameter of 14-16 μm to 1.6mm, mixing with water soluble phenolic resin and solvent, pulping, wet forming, carbonizing at 1440 ° F (782.2 deg.C) after phenolic resin is cured, and heat treating at 3240 ° F (1782.2 deg.C) to obtain the final product

Carbon fiber rigidity heat insulating tile.

The density of the carbon fiber rigid heat insulation tile is 0.15-0.23g/cm³The compressive strength in the thickness direction is 0.2-0.6 MPa. Changqing Hong et al prepared a carbon fiber based ablative material PICA (phenolic imprinted 3-D fine-w oven perforated carbon fiber fabric), the density of which was 0.352-0.701 g/cm³At 4.5MW/m²In the oxy/acetylene flame ablation test, the linear ablation rate is 0.019-0.036 mm/s, and the mass ablation rate is 0.045-0.061 g/s. The PICA material is prepared from 3D fine woven puncture carbon fiber preform composite phenolic resin. However, these materials all use the phenolic resin cracked carbon residue as a bonding phase, and burn in the air atmosphere at a high temperature of 1200 ℃, resulting in low oxidation resistance and insufficient temperature resistance.

Disclosure of Invention

The invention aims to overcome the defects of insufficient mechanical strength and insufficient temperature resistance of the existing carbon fiber rigid heat insulation tile, and finally provides a carbon fiber light rigid heat insulation tile with higher temperature resistance, light weight and higher strength and a preparation method thereof by adopting different technical schemes, which can be used as a thermal protection material for an oxygen-free atmosphere ultrahigh-temperature sintering furnace, nuclear power station high-temperature equipment, a chemical reactor and the like.

Therefore, the invention achieves the purpose through the following technical scheme:

1. a carbon fiber rigid heat insulation tile comprises chopped carbon fibers forming a framework and a Si/C/O glass bonding phase used for bonding the chopped carbon fibers.

2. The carbon fiber rigid heat insulation tile is obtained according to the technical scheme 1, wherein the Si/C/O glass bonding phase is prepared by mixing a silicon resin prepolymer, a cross-linking agent, a catalyst and an organic solvent according to the mass ratio of 10 (0.1-10) to (10-100) to prepare a silicon resin precursor mixed solution, sucking the silicon resin precursor mixed solution into a carbon fiber dry blank through a vacuum impregnation technology, and performing room temperature curing, carbonization and high temperature heat treatment.

3. The carbon fiber rigid heat insulation tile according to claim 2, wherein:

the silicone prepolymer is selected from one or a mixture of more of hydroxyl-terminated polydimethylsiloxane, hydroxyl-terminated polydiphenylsiloxane, hydroxyl-terminated phenyl-substituted polydimethylsiloxane, amino-terminated polydimethylsiloxane and epoxy-terminated polydimethylsiloxane; the viscosity of the silicone resin prepolymer is 200-100000 cst; and/or

The cross-linking agent is one or a mixture of more of ethyl orthosilicate, methyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane and dimethyldiethoxysilane; and/or

The catalyst is dibutyltin dilaurate or gamma-aminopropyltriethoxysilane; and/or

The organic solvent is one or a mixture of several selected from the group consisting of benzene, xylene, styrene and acetone.

4. The carbon fiber rigid heat insulation tile according to the technical scheme 1 or 2, wherein the length of the carbon fiber is 1-5 mm, and the diameter of the carbon fiber is 8-12 microns.

5. A preparation method of a carbon fiber rigid heat insulation tile comprises the following steps:

(1) wet forming to obtain wet blank of the chopped carbon fiber, and drying to obtain dry blank of the carbon fiber;

(2) mixing a silicone prepolymer, a cross-linking agent, a catalyst and an organic solvent to prepare a silicone precursor mixed solution;

(3) and impregnating the carbon fiber dry blank with a silicon resin precursor mixed solution, and curing at room temperature, carbonizing and performing high-temperature heat treatment to obtain the carbon fiber rigid heat insulation tile.

6. The method for preparing the carbon fiber rigid heat insulation tile according to the claim 5, wherein the step (2):

mixing the silicone prepolymer, the cross-linking agent, the catalyst and the organic solvent according to the mass ratio of (0.1-10) to (10-100) to prepare a silicone precursor mixed solution.

7. The method for manufacturing the carbon fiber rigid heat insulation tile according to claim 5 or 6, wherein in the step (2):

8. The method for preparing the carbon fiber rigid heat insulation tile according to the claim 5, wherein the step (1) comprises:

mixing the chopped carbon fibers with water according to a mass ratio of 1: 150-250, stirring and pulping, filtering to obtain a wet blank, then loading the wet blank into a shaping mold, pressing the wet blank to a preset height according to the target density of the material, and drying at 60-150 ℃ for 4-36 hours to obtain a carbon fiber dry blank.

9. The preparation method of the carbon fiber rigid heat insulation tile according to the claim 5, wherein the step (1) further comprises the step of removing glue:

cutting the carbon fibers to 1-5 mm to obtain short carbon fibers, mixing the short carbon fibers with acetone, heating the acetone to 55-60 ℃ and refluxing for 24-72 hours under the conditions of stirring and water-cooling refluxing, cleaning the epoxy resin surface treatment agent attached to the surfaces of the short carbon fibers, filtering through a filter screen, and volatilizing the acetone to obtain the short carbon fibers.

10. The method for preparing the carbon fiber rigid heat insulation tile according to the claim 5, wherein the step (3) comprises:

the vacuum impregnation and room temperature curing are specifically as follows: firstly, placing the carbon fiber dry blank obtained in the step (1) and a shaping mold in a vacuum impregnation tank, sealing the vacuum impregnation tank and vacuumizing to 10 DEG^-2～10^-4atm; will be described in detail(2) Injecting the prepared silicon resin precursor mixed solution into the vacuum impregnation tank, enabling the liquid level to be over the upper surface of the shaping mold, opening an air release valve to enable the air pressure in the tank body to be balanced to 1atm, and standing for 24-100 hours to enable the silicon resin to be crosslinked and cured; and/or

Heating the carbonized material in an argon atmosphere furnace to 600-1000 ℃ and preserving heat for 1-10 hours; and/or

And heating the high-temperature heat treatment in an argon atmosphere furnace to 1500-2200 ℃ and preserving the heat for 1-10 hours.

The carbon fiber rigid heat insulation tile and the preparation method thereof have the following beneficial effects:

1. the bonding phase between the carbon fibers is prepared by using the silicone resin, a Si/C/O glass bonding phase is generated during carbonization and cracking, the Si/C/O glass bonding phase covers the surface of the carbon fibers and the intersection points of the carbon fibers and plays a role of bonding a short carbon fiber framework, and a layer of silica glass film is generated on the surface after the Si/C/O glass bonding phase is oxidized in a high-temperature aerobic environment, so that oxygen atoms are prevented from further oxidizing internal substances, and the silicon/C/O glass bonding phase has oxidation resistance. Therefore, compared with the material adopting the phenolic resin cracked carbon residue as the bonding phase, the carbon fiber rigid heat insulation tile prepared by the invention has stronger oxidation resistance. On the other hand, compared with the method using starch as a binder, the carbon residue rate of the silicon resin cracked under the inert atmosphere is higher than that of gelatinized starch, so the mechanical strength is also higher by 20-50%.

2. According to the invention, the silicon resin precursor mixed liquid is fully combined with the carbon fiber dry blank through a vacuum impregnation process, and the formed carbon fiber rigid heat insulation tile has uniform material and stable overall performance, and is more beneficial to the Si/C/O glass bonding phase to exert the bonding effect.

3. The invention optimizes the proportion of the raw materials in the used silicon resin precursor mixed solution, and when the silicon resin prepolymer, the cross-linking agent, the catalyst and the organic solvent are prepared according to the mass ratio of (0.1-10) to (10-100), the cracked Si/C/O glass bonding phase can be distributed more uniformly, the mechanical strength is higher and the oxidation resistance is better.

Drawings

FIG. 1 is a flow chart of a process for manufacturing carbon fiber rigid insulation tiles according to a preferred embodiment of the present invention;

FIG. 2 is a photograph of a carbon fiber rigid insulation tile made in accordance with a preferred embodiment of the present invention;

fig. 3 is a scanning electron micrograph of a carbon fiber rigid heat insulation tile manufactured according to a preferred embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

As described above, the present invention provides in a first aspect a carbon fiber rigid thermal insulating tile, wherein the carbon fiber rigid thermal insulating tile comprises chopped carbon fibers constituting a skeleton, and a Si/C/O glass bonding phase for bonding the chopped carbon fibers.

In some preferred embodiments, the chopped carbon fibers have a length of 1 to 5mm and a diameter of 8 to 12 μm. More preferably, the chopped carbon fibers have a length of 2mm and a diameter of 10 μm. The carbon fibers used in the present invention may be, but are not limited to, T-300, T-700, T-800, T-1000, and the like.

In some more preferred embodiments, the Si/C/O glass bonding phase is prepared by preparing a silicone resin prepolymer a, a cross-linking agent B, a catalyst C and an organic solvent D into a silicone resin precursor mixed solution, then sucking the silicone resin precursor mixed solution into a carbon fiber dry blank by a vacuum impregnation technology, and then curing at room temperature, carbonizing and performing high-temperature heat treatment. Preferably, the mass ratio of the silicone prepolymer A, the cross-linking agent B, the catalyst C and the organic solvent D in the silicone precursor mixed solution is 10 (0.1-10) to (10-100). For example, 10: (0.1, 0.5, 2, 5 or 10): 10, 20, 50 or 100).

The invention uses silicone to prepare the bonding phase between the carbon fibers. The silicone resin dispersed phase is uniformly dispersed on the surface of the carbon fiber and at the intersection point of the carbon fiber and the carbon fiber after being cured. When carbonized and cracked at 800 ℃, the silicon resin is cracked to generate a Si/C/O glass bonding phase, namely SiC_xO_yAnd the glass phase covers the surface of the carbon fiber and the intersection point of the carbon fiber and the carbon fiber, and plays a role in bonding the chopped carbon fiber skeleton. Because the surface of the Si/C/O glass bonding phase can generate a layer of silicon dioxide glass film after being oxidized in a high-temperature aerobic environment, so as to prevent oxygen atoms from further oxidizing internal substances, the Si/C/O glass bonding phase has oxidation resistance, and has small ablation shrinkage and high reliability when subjected to high temperature; if epoxy resin or phenolic aldehyde is used instead of silicone resin, there is substantially no residue after ablation under sufficient oxygen, the ablation shrinkage is large, and the reliability is significantly low.

In some more preferred embodiments, the silicone prepolymer a is selected from one or a mixture of several of the group consisting of hydroxyl-terminated polydimethylsiloxane, hydroxyl-terminated polydiphenylsiloxane, hydroxyl-terminated phenyl-substituted polydimethylsiloxane, amino-terminated polydimethylsiloxane, and epoxy-terminated polydimethylsiloxane. Wherein the hydroxyl-terminated phenyl-substituted polydimethylsiloxane can be partially phenyl-substituted, and the substitution degree can be 30-70%. More preferably, the viscosity of the silicone resin prepolymer is 200 to 100000 cst; further preferably 10000-20000 CSt; further preferably 2000 to 4000 CSt.

In some more preferred embodiments, the crosslinking agent B is selected from one or a mixture of several of the group consisting of ethyl orthosilicate, methyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, and dimethyldiethoxysilane; more preferably, the crosslinking agent B is tetraethoxysilane.

In some more preferred embodiments, the catalyst C is dibutyltin dilaurate or gamma-aminopropyltriethoxysilane. The inventor finds that in the system, dibutyltin dilaurate is used as a catalyst, so that the curing reaction speed is higher, and the complete curing time is not more than 24 hours; if other catalysts such as gamma-aminopropyltriethoxysilane are used as the catalyst, a full cure time of 48 hours or more is required. Thus in some preferred embodiments, the catalyst C is dibutyltin dilaurate.

In some preferred embodiments, the organic solvent D is selected from one or a mixture of several of the group consisting of benzene, xylene, styrene and acetone; further preferably, the organic solvent D is xylene. In a more preferred embodiment, the silicone prepolymer A is hydroxyl-terminated polydimethylsiloxane, the crosslinking agent B is ethyl orthosilicate, the catalyst C is dibutyltin dilaurate, and the organic solvent D is xylene, and the mixture is uniformly mixed according to a mass ratio of 10:1:0.1:50 to obtain a silicone precursor mixed solution.

The invention provides a preparation method of a carbon fiber rigid heat insulation tile in a second aspect. Referring to fig. 1, a flow chart of a process for manufacturing a carbon fiber rigid heat insulation tile according to a preferred embodiment of the present invention is shown. Wherein, the preparation method comprises the following steps:

(3) and (3) impregnating the carbon fiber dry blank with the silicon resin precursor mixed liquor, for example, impregnating the carbon fiber dry blank by a vacuum impregnation process, so that the carbon fiber dry blank absorbs the silicon resin precursor mixed liquor, and then curing at room temperature, carbonizing and performing high-temperature heat treatment to obtain the carbon fiber rigid heat insulation tile.

In some preferred embodiments, in step (1): mixing the chopped carbon fibers with water according to a mass ratio of 1: 150-250, stirring and pulping, filtering to obtain a wet blank, then loading the wet blank into a shaping mold, pressing the wet blank to a preset height according to the target density of the material, and drying at 60-150 ℃ for 4-36 hours to obtain a carbon fiber dry blank. Specifically, the chopped carbon fibers after the degumming are mixed with deionized water, fully stirred and pulped in a stirring barrel, the slurry is transferred to a filtering tool, most of water is filtered out, then a wet blank is put into a shaping mold, the wet blank is pressed to a preset height according to the target density of the material, and the wet blank is dried for 4 to 36 hours (4, 10, 20, 30 or 36) at 60 to 150 ℃ (such as 60 ℃, 80 ℃, 100 ℃ or 150 ℃) to obtain a dry carbon fiber blank; the mass ratio of the chopped carbon fibers to the deionized water is 1:150 to 250 (e.g., 1:150, 1:200 or 1:250), and more preferably 1: 200.

In some more preferred embodiments, the step (1) further comprises a step of removing the glue: namely, the carbon fiber with the diameter of 8-12 mu m is cut into 1-5 mm to obtain the short carbon fiber. And then mixing the chopped carbon fibers with acetone, heating the acetone to 55-60 ℃ under the conditions of stirring and water-cooling reflux, refluxing for 24-72 hours, cleaning the epoxy resin surface treating agent attached to the surfaces of the chopped carbon fibers, filtering through a filter screen, and volatilizing the acetone to obtain the chopped carbon fibers. Specifically, the chopped carbon fibers are placed in a kettle filled with acetone, and a stirring and water-cooling reflux device is arranged at the top of the kettle. And opening a stirring and water-cooling reflux device, heating acetone to 55-60 ℃ (such as 55 ℃, 58 ℃ or 60 ℃) and refluxing for 24-72 hours (24, 36, 48 or 72 hours), and thoroughly cleaning the epoxy resin adhesive attached to the surface of the carbon fiber. One optimized degumming procedure is a constant temperature 60 ℃ reflux for 48 hours, which is sufficient to thoroughly clean the epoxy resin adhesive attached to the surface of the carbon fiber. Subsequently, the carbon fibers cleaned in the kettle are filtered out through a filter screen and dried in a fume hood, so that the acetone is fully volatilized.

In some preferred embodiments, in step (2): mixing the silicone prepolymer A, the cross-linking agent B, the catalyst C and the organic solvent D according to the mass ratio of (0.1-10) to (10-100) to prepare a silicone precursor mixed solution. For example, 10: (0.1, 0.5, 2, 5 or 10): 10, 20, 50 or 100). Wherein the silicone prepolymer a, the crosslinking agent B, the catalyst C and the organic solvent D are as described in the first aspect of the invention.

In some preferred embodimentsThe vacuum impregnation and room temperature curing in the step (3) are specifically as follows: firstly, placing the carbon fiber dry blank obtained in the step (1) and a shaping mold in a vacuum impregnation tank, sealing and locking the vacuum impregnation tank, and vacuumizing to 10 DEG^-2～10^-4atm, more preferably 10^-4atm; and (3) injecting the silicon resin precursor mixed solution prepared in the step (2) into the vacuum impregnation tank, enabling the liquid level to be over the upper surface of the shaping mold, opening an air release valve to enable the air pressure in the tank body to be balanced to 1atm, and standing for 24-100 hours to enable the silicon resin to be fully crosslinked and cured at room temperature.

In some preferred embodiments, the carbonization treatment in step (3) is specifically: and (3) putting the cured carbon fiber rigid heat insulation tile blank into a carbonization furnace, heating to 600-1000 ℃ (for example, 600 ℃, 800 ℃ or 1000 ℃) in an argon atmosphere, and preserving heat for 1-10 hours (for example, 1, 2, 5 or 10 hours) to completely carbonize the silicone resin to generate the Si/C/O glass bonding phase. In a more preferable embodiment, the carbon fiber rigid heat insulation tile is heated to 800 ℃ in an argon atmosphere furnace and is kept for 2 hours to obtain a carbon fiber rigid heat insulation tile mature blank.

In some preferred embodiments, the high-temperature heat treatment in step (3) is specifically: heating to 1500-2200 deg.C (such as 1500 deg.C, 1800 deg.C or 2200 deg.C) in an argon atmosphere furnace, and maintaining for 1-10 hours (such as 1, 2, 5 or 10 hours). For example, the carbon fiber rigid heat insulation tile blank is put into a cracking furnace in an argon atmosphere, heated to 1800 ℃ and kept for 1 hour to eliminate the thermal stress accumulated in the heat insulation tile blank in the resin curing and carbonizing processes, and finally the carbon fiber rigid heat insulation tile product is obtained.

Referring to fig. 2 and 3, a photograph of a carbon fiber rigid heat insulation tile according to a preferred embodiment of the present invention is shown. As can be seen from FIG. 2, the carbon fiber rigid heat insulation tile comprises a chopped carbon fiber skeleton and a cracked Si/C/O glass bonding phase distributed among the chopped carbon fibers, wherein the Si/C/O glass bonding phase covers the surface of the carbon fibers and the intersection points of the carbon fibers and plays a role in bonding the chopped carbon fiber skeleton.

The present invention will be further described in the following examples, but since the inventor is unlikely and not necessarily exhaustive to show all technical solutions obtained based on the inventive concept, the scope of the present invention should not be limited to the following examples, but should include all technical solutions obtained based on the inventive concept.

Example 1

Cutting carbon fibers with the diameter of 10 mu m to 2mm, placing the cut carbon fibers in a kettle filled with acetone, and installing a stirring and water-cooling reflux device at the top of the kettle. And opening a stirring and water-cooling reflux device, heating the acetone to 55 ℃ and refluxing for 48 hours, and thoroughly cleaning the epoxy resin adhesive attached to the surface of the carbon fiber. And filtering the carbon fibers cleaned in the kettle out through a filter screen, and airing in a fume hood to fully volatilize the acetone.

Secondly, mixing the degummed chopped carbon fibers with deionized water according to the mass ratio of 1:150, fully stirring and pulping in a stirring barrel, transferring the slurry into a filtering tool, filtering most of water, then loading a wet blank into a shaping mold, pressing the wet blank to a preset height according to the target density of the material, and drying at 120 ℃ for 24 hours to obtain a dry carbon fiber blank.

Thirdly, placing the carbon fiber dry blank with the shaping mold into a vacuum impregnation tank, sealing and locking the impregnation tank, and then vacuumizing the impregnation tank to 10 DEG^-2atm。

Preparing a mixed liquid of a silicon resin precursor: uniformly mixing hydroxyl-terminated polydimethylsiloxane, tetraethoxysilane, dibutyltin dilaurate and dimethylbenzene according to the mass ratio of 10:1:0.1:50 for later use. Wherein the viscosity of the hydroxyl-terminated polydimethylsiloxane is 4000 cst.

Fifthly, injecting the mixed liquid of the silicon resin precursor prepared in the step IV into a vacuum impregnation tank to ensure that the liquid level is over the upper surface of the shaping mold, opening a vent valve to ensure that the air pressure in the tank body is balanced to 1atm, and standing for 24 hours to ensure that the silicon resin is fully crosslinked and cured.

Sixthly, putting the cured carbon fiber rigid heat insulation tile blank into a carbonization furnace, heating to 800 ℃ in an argon atmosphere, and preserving heat for 2 hours to completely carbonize the silicon resin and generate a Si/C/O glass bonding phase.

Seventhly, putting the cooked carbon fiber rigid heat insulation tile blank prepared in the step sixthly into a cracking furnace in an argon atmosphere, heating to 1800 ℃, and preserving heat for 2 hours to eliminate thermal stress accumulated in the heat insulation tile blank body in the resin curing and carbonizing processes, and finally obtaining the carbon fiber rigid heat insulation tile product.

Examples 2 to 22

Examples 2 to 22 were carried out in the same manner as in example 1 except for the contents shown in the following table 1 and table 2. The mechanical strength of the prepared carbon fiber rigid heat insulation tile is tested, and the result is shown in table 2.

Comparative examples 1 to 2

The present invention also employs the fibrous insulation disclosed in U.S. patent No. 3577344 as comparative example 1. The preparation process comprises the following steps: cutting carbon fibers with the average diameter of 0.5-0.7 mu m into 0.25 inch long, mixing the carbon fibers, starch and water, and pulping to obtain slurry, wherein the mass ratio of the starch to the carbon fibers in the prepared slurry is 0.75:1, and the ratio of the carbon fibers to the water is 380L corresponding to 1kg of the carbon fibers. The slurry was filtered through a 0.25 inch screen and stirred for 30 minutes before being poured into a mold. The water was removed for 7 minutes by a vacuum tank in communication therewith and the temperature of the mold was increased to 95 degrees celsius. The mixture was allowed to stand for 4 hours under an atmosphere of saturated steam to gelatinize the starch. Thereafter, the prepared composite was dried in a lower humidity environment for 24 hours, followed by heating at 1000 degrees celsius for 16 hours to effect carbonization. The fibrous heat insulating material of comparative example 1 was examined to have a compressive strength in the thickness direction of 0.1 to 0.2 MPa. Therefore, the compression strength of the carbon fiber rigid heat insulation tile prepared by the method in the thickness direction is generally 20-50% higher than that of the fiber heat insulation material prepared by the comparative example 1, and some of the compression strength is even higher than that of the fiber heat insulation material prepared by the comparative example 1 by more than 100%. The carbon residue rate of the silicon resin cracked in the inert atmosphere in the carbon fiber rigid heat insulation tile prepared by the invention is higher than that of gelatinized starch.

The present invention also employs the carbon fiber rigid insulation tile disclosed in U.S. patent No. 4152482 as comparative example 2. The preparation process comprises the following steps: cutting carbon fibers with the average diameter of 5-7 mu m into 250 mu m, mixing the carbon fibers with phenolic resin according to the mass ratio of 1:0.35, wherein the particle size of the phenolic resin is about 10 mu m, and filtering the carbon fibers through a 0.5mm filter screen. Then the mixture was slurried after adding water, 300L of water per 1kg of mixture, and the slurry was stirred for 20 minutes and then poured into molds. Dewatering for 15 min via communicated vacuum tank, and forming the composite of carbon fiber and phenolic resin under vacuum condition. The mold temperature was heated to 130 ℃. The phenolic resin was cured by standing for 24 hours under an air atmosphere, and excess moisture was removed. The obtained material was heated to 1000 ℃ in a nitrogen atmosphere and carbonized after continuing heating for 30 minutes to obtain the carbon fiber rigid heat insulation tile of comparative example 2. And (3) heating at 1200 ℃ for 5min in an air atmosphere to detect the oxidation resistance of the carbon fiber rigid heat insulation tile in the comparative example 2. The experimental result shows that the carbon fiber rigid heat insulation tile prepared in the comparative example 2 generates a combustion phenomenon at 1200 ℃, and the final residual mass is 0.5%. In the invention, because the Si/C/O glass bonding phase of the product of cracking the silicone resin in the inert atmosphere has oxidation resistance, the carbon fiber rigid heat insulation tile prepared in the embodiment 1-11 has no structural collapse after being heated at 1200 ℃ for 5min, and the mass increase is 10-20%.

Claims

1. A carbon fiber rigid heat insulation tile is characterized by comprising chopped carbon fibers forming a framework and a Si/C/O glass bonding phase for bonding the chopped carbon fibers;

the Si/C/O glass bonding phase is generated during carbonization and cracking by using silicon resin to prepare a bonding phase among carbon fibers;

the Si/C/O glass bonding phase is prepared by preparing a silicon resin precursor mixed solution from a silicon resin prepolymer, a cross-linking agent, a catalyst and an organic solvent according to the mass ratio of 10 (0.1-10) to 0.1-10 to 10-100, sucking the silicon resin precursor mixed solution into a carbon fiber dry blank by a vacuum impregnation technology, and performing room-temperature curing, carbonization and high-temperature heat treatment to obtain the silicon resin/C/O glass bonding phase;

the silicone prepolymer is selected from one or a mixture of more of hydroxyl-terminated polydimethylsiloxane, hydroxyl-terminated polydiphenylsiloxane, hydroxyl-terminated phenyl-substituted polydimethylsiloxane, amino-terminated polydimethylsiloxane and epoxy-terminated polydimethylsiloxane; wherein the hydroxyl-terminated phenyl-substituted polydimethylsiloxane is partially phenyl-substituted, and the degree of substitution is 30 to 70 percent; the viscosity of the silicone resin prepolymer is 200-100000 cst;

the cross-linking agent is one or a mixture of more of ethyl orthosilicate, methyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane and dimethyldiethoxysilane;

the catalyst is dibutyltin dilaurate or gamma-aminopropyltriethoxysilane;

2. The carbon fiber rigid heat insulation tile according to claim 1, wherein the viscosity of the silicone prepolymer is 10000 to 20000 CSt.

3. The carbon fiber rigid insulation tile according to claim 1, wherein the viscosity of the silicone prepolymer is 2000-4000 CSt.

4. The carbon fiber rigid insulation tile according to claim 1, wherein:

the silicone resin prepolymer is hydroxyl-terminated polydimethylsiloxane, the crosslinking agent is ethyl orthosilicate, the catalyst is dibutyltin dilaurate, the organic solvent is xylene, and the silicone resin prepolymer and the catalyst are uniformly mixed according to the mass ratio of 10:1:0.1:50 to obtain a silicone resin precursor mixed solution; and/or

The length of the short carbon fiber is 1-5 mm, and the diameter of the short carbon fiber is 8-12 mu m.

5. The carbon fiber rigid insulation tile according to claim 4, wherein:

the chopped carbon fibers have a length of 2mm and a diameter of 10 μm.

6. A preparation method of a carbon fiber rigid heat insulation tile is characterized by comprising the following steps:

(3) impregnating the carbon fiber dry blank with a silicon resin precursor mixed solution, and then carrying out room-temperature curing, carbonization and high-temperature heat treatment to obtain a carbon fiber rigid heat insulation tile;

in the step (2):

mixing a silicone prepolymer, a cross-linking agent, a catalyst and an organic solvent according to a mass ratio of (0.1-10) to (10-100) to prepare a silicone precursor mixed solution;

in the step (2):

the catalyst is dibutyltin dilaurate or gamma-aminopropyltriethoxysilane;

7. The method for preparing the carbon fiber rigid heat insulation tile according to claim 6, wherein the viscosity of the silicone prepolymer is 10000-20000 CSt.

8. The method for preparing the carbon fiber rigid heat insulation tile according to claim 7, wherein the viscosity of the silicone prepolymer is 2000-4000 CSt.

9. The preparation method of the carbon fiber rigid heat insulation tile according to claim 6, wherein the silicone prepolymer is hydroxyl-terminated polydimethylsiloxane, the cross-linking agent is ethyl orthosilicate, the catalyst is dibutyltin dilaurate, and the organic solvent is xylene, and the silicone prepolymer and the cross-linking agent are uniformly mixed according to a mass ratio of 10:1:0.1:50 to obtain a silicone precursor mixed solution.

10. The method for preparing a carbon fiber rigid heat insulation tile according to claim 6 or 9, wherein:

in the step (1): mixing the chopped carbon fibers with water according to a mass ratio of 1: 150-250, stirring and pulping, filtering to obtain a wet blank, then loading the wet blank into a shaping mold, pressing the wet blank to a preset height according to the target density of the material, and drying at 60-150 ℃ for 4-36 hours to obtain a carbon fiber dry blank.

11. The method for preparing the carbon fiber rigid heat insulation tile according to the claim 10, wherein in the step (1): the chopped carbon fibers were mixed with water in a mass ratio of 1: 200.

12. The method for preparing the carbon fiber rigid heat insulation tile according to claim 10, wherein the method comprises the following steps:

the step (1) further comprises the step of removing glue: cutting the carbon fibers to 1-5 mm to obtain short carbon fibers, mixing the short carbon fibers with acetone, heating the acetone to 55-60 ℃ under the conditions of stirring and water-cooling reflux for 24-72 hours, cleaning the epoxy resin surface treatment agent attached to the surfaces of the short carbon fibers, filtering through a filter screen, and volatilizing the acetone to obtain the short carbon fibers.

13. The method for preparing the carbon fiber rigid heat insulation tile according to claim 12, wherein the method comprises the following steps:

the chopped carbon fibers have a length of 2mm and a diameter of 10 μm.

14. The method for preparing the carbon fiber rigid heat insulation tile according to claim 12, wherein the method comprises the following steps:

the procedure of removing the gel is to reflux at a constant temperature of 60 ℃ for 48 hours.

15. The method for preparing the carbon fiber rigid heat insulation tile according to the claim 6 or 9, wherein in the step (3):

the vacuum impregnation and room temperature curing are specifically as follows: firstly, placing the carbon fiber dry blank obtained in the step (1) and a shaping mold in a vacuum impregnation tank, sealing the vacuum impregnation tank and vacuumizing to 10 DEG^-2～10^-4atm; injecting the silicon resin precursor mixed solution prepared in the step (2) into the vacuum impregnation tank, enabling the liquid level to be over the upper surface of the shaping mold, opening an air release valve to enable the air pressure in the tank body to be balanced to 1atm, and standing for 24-100 hours to enable the silicon resin to be crosslinked and cured; and/or

16. The method for preparing the carbon fiber rigid heat insulation tile according to claim 15, wherein the method comprises the following steps: and heating the carbonized tiles to 800 ℃ in an argon atmosphere furnace, and preserving heat for 2 hours to obtain the carbon fiber rigid heat insulation tile cooked blanks.

17. The method for preparing the carbon fiber rigid heat insulation tile according to claim 15, wherein the method comprises the following steps:

the high-temperature heat treatment is carried out in an argon atmosphere furnace, the temperature is raised to 1800 ℃, and the heat is preserved for 1 hour.