Viscose-based light heat insulation felt and preparation method thereof

Abstract

The invention discloses a viscose-based light heat insulation felt and a preparation method thereof, and relates to the technical field of heat insulation felts.In order to improve the strength and the use performance of a viscose-based carbon fiber heat insulation felt, the technology is improved in the preparation process, firstly, viscose fibers are subjected to dipping treatment through a catalyst, and then the viscose fibers are subjected to heat insulation treatment; therefore, elements such as hydrogen and oxygen in the viscose fibers are removed as much as possible in the pre-oxidation stage, ash impurities after carbon fiber forming are reduced, then on the basis, modified phenolic resin is further prepared, boron is introduced into the modified phenolic resin, and in the subsequent dipping treatment process, the content of carbon fibers in the modified phenolic resin is reduced. The phenolic resin containing the boron element can be attached to the fiber felt subjected to pre-oxidation treatment, in the high-temperature graphitization process, the boron element can further catalyze the graphitization degree of carbides, and collapse of the carbon material at the high temperature is avoided, so that the strength of the heat insulation felt is improved, and the defects of slag falling and ash falling are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal insulation felt, in particular to a viscose-based light thermal insulation felt and a preparation method thereof. BACKGROUND

[0002] The viscose-based carbon fiber felt is a carbon-based material in the form of a fiber felt, which is obtained by two processes of filament weaving and graphitization treatment of viscose fibers, has the characteristics of light density, strong corrosion resistance, outstanding high-temperature resistance, significant fatigue resistance, small thermal expansion coefficient, etc., and has good flexibility, and can realize efficient thermal insulation by wrapping, but in the specific application process, due to the property characteristics of the fiber felt, it is inevitable that the fiber felt has the defects of high ash content and low strength, and further causes defects such as slagging and ashing. SUMMARY

[0003] The present application relates to the technical field of thermal insulation felt, in particular to a viscose-based light thermal insulation felt and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a preparation method of a viscose-based light thermal insulation felt, comprising the following steps:

[0005] S1. The viscose fiber is prepared into a viscose fiber felt by needle punching process, and then immersed in a catalyst solution, and after immersion for 20-45 min, the excess liquid is separated by centrifugation, and then heated to 85-95 DEG C, and dried for 1-2 h, and then placed in a pre-oxidation furnace for pre-oxidation treatment.

[0006] S2. The fiber felt after pre-oxidation treatment is completely immersed in a modified phenolic resin, and after ultrasonic treatment for 10-15 min, it is taken out and heated to 150-160 DEG C, and solidified for 15-30 min.

[0007] S3. The solidified fiber felt is placed in a carbonization furnace for carbonization and graphitization treatment, and after the treatment is completed, a viscose-based light thermal insulation felt is obtained.

[0008] Further, in step S1, the catalyst solution is a mixed aqueous solution of ammonium sulfate and hydrogen diamine phosphate, wherein the concentration of ammonium sulfate is 0.5-1.5 wt%, and the concentration of hydrogen diamine phosphate is 1-2 wt%.

[0009] Further, in step S1, during pre-oxidation treatment, the temperature is raised to 135-150 DEG C, and after holding for 5-10 min, the temperature is raised to 200-210 DEG C at a rate of 1-5 DEG C / min, and after holding for 10-20 min, the temperature is raised to 275-300 DEG C again, and after holding for 15-25 min, the furnace is cooled to room temperature, and the fiber felt after pre-oxidation treatment is obtained.

[0010] Further, in step S1, during the pre-oxidation treatment, an inert gas atmosphere is used for protection.

[0011] The inert gas is any one of nitrogen and argon.

[0012] Further, in step S2, the preparation method of the modified phenolic resin comprises the following steps:

[0013] a. The hydroquinone is dispersed in diethyl ether, after stirring and uniformly mixing, 1,4-benzene diboronic acid is added, after uniformly mixing and stirring, concentrated sulfuric acid is added, the temperature is raised to 150-175 DEG C, and the reaction is carried out in the dark for 2-4 h, then the temperature is cooled to room temperature, and after 1-2 times of washing with cold deionized water, drying is carried out, to obtain a boron-containing diphenol intermediate;

[0014] b. The phenol and the boron-containing diphenol intermediate are added to anhydrous ethanol, after ultrasonic stirring and uniformly mixing, sodium hydroxide solution and formaldehyde aqueous solution are added, and after stirring and reaction polymerization, the modified phenolic resin is obtained.

[0015] Further, in step a, the adding amount of each component is 10 parts of hydroquinone, 7-8 parts of 1,4-benzene diboronic acid, and 1-3 parts of concentrated sulfuric acid, by weight.

[0016] Further, in step b, the adding amount of each component is 10 parts of phenol, 0.5-1 parts of the boron-containing diphenol intermediate, 0.1-0.15 parts of sodium hydroxide, and 4.5-6.5 parts of formaldehyde, by weight.

[0017] Further, in step S3, during the graphitization treatment, the cured fiber felt is heated to 300-310 DEG C, and after heat preservation for 5-10 min, the temperature is raised to 500-505 DEG C at a rate of 1-5 DEG C / min, and after heat preservation for 10-20 min, the temperature is raised to 1200-1300 DEG C, and after heat preservation for 30-45 min, the temperature is raised to 1800-1850 DEG C, and after heat preservation for 0.5-1.5 h, the temperature is raised to 2000-2100 DEG C, and after heat preservation treatment for 1-2 h, the temperature is cooled to room temperature in the furnace, to obtain the viscose-based light thermal insulation felt.

[0018] Further, a viscose-based light thermal insulation felt is prepared by the above method.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] In order to improve the strength and use performance of the viscose-based carbon fiber thermal insulation felt, the process is improved in the preparation process.

[0021] The present invention first uses a catalyst containing ammonium sulfate and diamine hydrogen phosphate to impregnate viscose fibers, thereby removing hydrogen, oxygen and other elements in the viscose fibers as much as possible in the pre-oxidation stage, reducing ash impurities after carbon fiber molding, and then on this basis, the present application further prepares a modified phenolic resin, using hydroquinone to react with 1,4-phenylenediboric acid containing boron to form a boron-containing diphenol intermediate containing boron, and then mixing it with phenol and participating in the reaction of formaldehyde to generate a phenolic resin containing boron. In the subsequent impregnation process, the phenolic resin containing boron will adhere to the fiber felt after the pre-oxidation treatment. In the process of high-temperature graphitization, the boron element will further catalyze the graphitization degree of the carbide and cause the carbon material to collapse at high temperature, thereby improving the strength of the thermal insulation felt and reducing the defects of slagging and ash falling. DETAILED DESCRIPTION

[0022] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0023] Example 1. A method for preparing a viscose-based lightweight insulation felt, comprising the following steps:

[0024] S1. Viscose fibers were needle-punched to form a viscose fiber mat. The mat was then immersed in a catalytic solution for 30 minutes, centrifuged to remove excess liquid, heated to 90°C, dried for 1 hour, and placed in a pre-oxidation furnace for pre-oxidation. The temperature was then raised to 140°C, held at that temperature for 8 minutes, then raised to 205°C at a rate of 5°C / min, held at that temperature for 15 minutes, and then raised to 290°C again. The mat was held at that temperature for 20 minutes and then cooled to room temperature in the furnace to obtain a pre-oxidized fiber mat.

[0025] The catalytic solution is a mixed aqueous solution of ammonium sulfate and diammonium hydrogen phosphate, wherein the concentration of ammonium sulfate is 0.5wt% and the concentration of diammonium hydrogen phosphate is 1wt%;

[0026] S2. The pre-oxidized fiber mat was completely immersed in a modified phenolic resin, ultrasonically treated for 15 minutes, removed, heated to 150°C, and cured for 30 minutes;

[0027] The preparation method of the modified phenolic resin comprises the following steps:

[0028] a. Disperse 10 parts of hydroquinone in ether by weight, stir and disperse to mix evenly, add 7 parts of 1,4-phenylenediboronic acid thereto, mix and stir evenly, add 1 part of concentrated sulfuric acid thereto, heat to 175 ° C, react in the dark for 3 hours, cool to room temperature, rinse twice with cold deionized water, and dry to obtain a boron-containing diphenol intermediate;

[0029] b in parts by weight, 10 parts of phenol, 0.5 parts of the boron-containing diphenol intermediate were added to anhydrous ethanol, and after ultrasonic stirring to mix, thereto were added a sodium hydroxide solution containing 0.1 parts of sodium hydroxide and a formaldehyde solution containing 4.5 parts of formaldehyde, and the reaction was stirred and polymerized to obtain a modified phenolic resin;

[0030] S3. Place the cured fiber felt in a carbonization furnace for graphitization treatment. Raise the temperature of the cured fiber felt to 300°C, keep it warm for 8 minutes, then raise the temperature to 500°C at a rate of 5°C / min, keep it warm for 20 minutes, then raise the temperature to 1250°C again, keep it warm for 45 minutes, then raise the temperature to 1800°C again, keep it warm for 1 hour, then raise the temperature to 2100°C, keep it warm for 2 hours, and cool it to room temperature in the furnace. After the treatment is completed, a viscose-based lightweight insulation felt is obtained.

[0031] Example 2. A method for preparing a viscose-based lightweight insulation felt, comprising the following steps:

[0032] Compared with Example 1, this example increases the amount of the boron-containing diphenol intermediate added in step b;

[0033] S1. Viscose fibers were needle-punched to form a viscose fiber mat. The mat was then immersed in a catalytic solution for 30 minutes, centrifuged to remove excess liquid, heated to 90°C, dried for 1 hour, and placed in a pre-oxidation furnace for pre-oxidation. The temperature was then raised to 140°C, held at that temperature for 8 minutes, then raised to 205°C at a rate of 5°C / min, held at that temperature for 15 minutes, and then raised to 290°C again. The mat was held at that temperature for 20 minutes and then cooled to room temperature in the furnace to obtain a pre-oxidized fiber mat.

[0034] The catalytic solution is a mixed aqueous solution of ammonium sulfate and diammonium hydrogen phosphate, wherein the concentration of ammonium sulfate is 0.5wt% and the concentration of diammonium hydrogen phosphate is 1wt%;

[0035] S2. The pre-oxidized fiber mat was completely immersed in a modified phenolic resin, ultrasonically treated for 15 minutes, removed, heated to 150°C, and cured for 30 minutes;

[0036] The preparation method of the modified phenolic resin comprises the following steps:

[0037] a. Disperse 10 parts of hydroquinone in ether by weight, stir and disperse to mix evenly, add 7 parts of 1,4-phenylenediboronic acid thereto, mix and stir evenly, add 1 part of concentrated sulfuric acid thereto, heat to 175 ° C, react in the dark for 3 hours, cool to room temperature, rinse twice with cold deionized water, and dry to obtain a boron-containing diphenol intermediate;

[0038] b in parts by weight, 10 parts of phenol, 1 part of the boron-containing diphenol intermediate were added to anhydrous ethanol, and after ultrasonic stirring to mix, thereto were added a sodium hydroxide solution containing 0.1 parts of sodium hydroxide and a formaldehyde solution containing 4.5 parts of formaldehyde, and the reaction was stirred and polymerized to obtain a modified phenolic resin;

[0039] S3. Place the cured fiber felt in a carbonization furnace for graphitization treatment. Raise the temperature of the cured fiber felt to 300°C, keep it warm for 8 minutes, then raise the temperature to 500°C at a rate of 5°C / min, keep it warm for 20 minutes, then raise the temperature to 1250°C again, keep it warm for 45 minutes, then raise the temperature to 1800°C again, keep it warm for 1 hour, then raise the temperature to 2100°C, keep it warm for 2 hours, and cool it to room temperature in the furnace. After the treatment is completed, a viscose-based lightweight insulation felt is obtained.

[0040] Example 3. A method for preparing a viscose-based lightweight insulation felt, comprising the following steps:

[0041] Compared with Example 1, this example increases the concentration of each component in the catalyst in step S1;

[0042] S1. Viscose fibers were needle-punched to form a viscose fiber mat. The mat was then immersed in a catalytic solution for 30 minutes, centrifuged to remove excess liquid, heated to 90°C, dried for 1 hour, and placed in a pre-oxidation furnace for pre-oxidation. The temperature was then raised to 140°C, held at that temperature for 8 minutes, then raised to 205°C at a rate of 5°C / min, held at that temperature for 15 minutes, and then raised to 290°C again. The mat was held at that temperature for 20 minutes and then cooled to room temperature in the furnace to obtain a pre-oxidized fiber mat.

[0043] The catalytic solution is a mixed aqueous solution of ammonium sulfate and diammonium hydrogen phosphate, wherein the concentration of ammonium sulfate is 1.5wt% and the concentration of diammonium hydrogen phosphate is 2wt%;

[0044] S2. The pre-oxidized fiber mat was completely immersed in a modified phenolic resin, ultrasonically treated for 15 minutes, removed, heated to 150°C, and cured for 30 minutes;

[0045] The preparation method of the modified phenolic resin comprises the following steps:

[0046] a. Disperse 10 parts of hydroquinone in ether by weight, stir and disperse to mix evenly, add 7 parts of 1,4-phenylenediboronic acid thereto, mix and stir evenly, add 1 part of concentrated sulfuric acid thereto, heat to 175 ° C, react in the dark for 3 hours, cool to room temperature, rinse twice with cold deionized water, and dry to obtain a boron-containing diphenol intermediate;

[0047] b in parts by weight, 10 parts of phenol, 0.5 parts of the boron-containing diphenol intermediate were added to anhydrous ethanol, and after ultrasonic stirring to mix, thereto were added a sodium hydroxide solution containing 0.1 parts of sodium hydroxide and a formaldehyde solution containing 4.5 parts of formaldehyde, and the reaction was stirred and polymerized to obtain a modified phenolic resin;

[0048] S3. Place the cured fiber felt in a carbonization furnace for graphitization treatment. Raise the temperature of the cured fiber felt to 300°C, keep it warm for 8 minutes, then raise the temperature to 500°C at a rate of 5°C / min, keep it warm for 20 minutes, then raise the temperature to 1250°C again, keep it warm for 45 minutes, then raise the temperature to 1800°C again, keep it warm for 1 hour, then raise the temperature to 2100°C, keep it warm for 2 hours, and cool it to room temperature in the furnace. After the treatment is completed, a viscose-based lightweight insulation felt is obtained.

[0049] Comparative Example 1. A method for preparing a viscose-based lightweight insulation felt, comprising the following steps:

[0050] Compared with Example 1, this comparative example did not prepare a boron-containing diphenol intermediate;

[0051] S1. Viscose fibers were needle-punched to form a viscose fiber mat. The mat was then immersed in a catalytic solution for 30 minutes, centrifuged to remove excess liquid, heated to 90°C, dried for 1 hour, and placed in a pre-oxidation furnace for pre-oxidation. The temperature was then raised to 140°C, held at that temperature for 8 minutes, then raised to 205°C at a rate of 5°C / min, held at that temperature for 15 minutes, and then raised to 290°C again. The mat was held at that temperature for 20 minutes and then cooled to room temperature in the furnace to obtain a pre-oxidized fiber mat.

[0052] The catalytic solution is a mixed aqueous solution of ammonium sulfate and diammonium hydrogen phosphate, wherein the concentration of ammonium sulfate is 0.5wt% and the concentration of diammonium hydrogen phosphate is 1wt%;

[0053] S2. The pre-oxidized fiber mat was completely immersed in a modified phenolic resin, ultrasonically treated for 15 minutes, removed, heated to 150°C, and cured for 30 minutes;

[0054] The preparation method of the modified phenolic resin comprises the following steps:

[0055] a. In parts by weight, 10 parts of phenol were added to anhydrous ethanol, and after ultrasonic stirring to mix, a sodium hydroxide solution containing 0.1 parts of sodium hydroxide and a formaldehyde solution containing 4.5 parts of formaldehyde were added thereto, and the reaction was stirred and polymerized to obtain a modified phenolic resin;

[0056] S3. Place the cured fiber felt in a carbonization furnace for graphitization treatment. Raise the temperature of the cured fiber felt to 300°C, keep it warm for 8 minutes, then raise the temperature to 500°C at a rate of 5°C / min, keep it warm for 20 minutes, then raise the temperature to 1250°C again, keep it warm for 45 minutes, then raise the temperature to 1800°C again, keep it warm for 1 hour, then raise the temperature to 2100°C, keep it warm for 2 hours, and cool it to room temperature in the furnace. After the treatment is completed, a viscose-based lightweight insulation felt is obtained.

[0057] Testing: According to GB / T 8722-2008 "Determination of thermal conductivity of graphite materials in Chinese", the viscose-based lightweight insulation felts prepared in Examples 1 to 3 and Comparative Example 1 were tested for thermal conductivity;

[0058] The viscose-based lightweight thermal insulation felts prepared in Examples 1 to 3 and Comparative Example 1 were prepared into test specimens of 50*50*10 mm, and the compressive strength thereof was tested using a universal material testing machine at a compression speed of 2 mm / min and stopped when the compression amount reached 5%;

[0059] The test results are shown in the table below;

[0060]

[0061] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a viscose-based lightweight thermal insulation felt, characterized in that: The following steps are involved: S1. Viscose fiber is needle-punched into a viscose fiber mat, which is then immersed in a catalytic solution for 20-45 minutes. Excess liquid is removed by centrifugation, and the mixture is heated to 85-95°C, dried for 1-2 hours, and then placed in a pre-oxidation furnace for pre-oxidation. S2. Completely immerse the pre-oxidized fiber mat in modified phenolic resin, ultrasonicate for 10-15 minutes, remove from the mold, heat to 150-160°C, and cure for 15-30 minutes. S3. Placing the cured fiber felt in a carbonization furnace for graphitization treatment to obtain a viscose-based lightweight insulation felt.

2. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 1, characterized in that: In step S1, the catalyst solution is a mixed aqueous solution of ammonium sulfate and diammonium hydrogen phosphate, wherein the concentration of ammonium sulfate is 0.5-1.5 wt %, and the concentration of diammonium hydrogen phosphate is 1-2 wt %.

3. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 1, characterized in that: In step S1, during the pre-oxidation treatment, the temperature is raised to 135~150°C, kept warm for 5~10 minutes, then raised to 200~210°C at a rate of 1~5°C / min, kept warm for 10~20 minutes, and then raised to 275~300°C again. After keeping warm for 15~25 minutes, the fiber felt is cooled to room temperature with the furnace to obtain a pre-oxidation treated fiber felt.

4. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 1, characterized in that: In step S1, during the pre-oxidation treatment, an inert gas atmosphere is used for protection; The inert gas is any one of nitrogen and argon.

5. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 1, characterized in that: In step S2, the preparation method of the modified phenolic resin comprises the following steps: a. Disperse hydroquinone in ether, stir and disperse to mix evenly, add 1,4-phenylenediboronic acid, mix and stir evenly, add concentrated sulfuric acid, heat to 150-175°C, react in the dark for 2-4 hours, cool to room temperature, rinse with cold deionized water 1-2 times, and dry to obtain a boron-containing diphenol intermediate; b. Phenol and the boron-containing diphenol intermediate are added to anhydrous ethanol and mixed by ultrasonic stirring. Then, sodium hydroxide solution and formaldehyde aqueous solution are added thereto. After stirring, the mixture is polymerized to obtain a modified phenolic resin.

6. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 5, characterized in that: In step a, the added amounts of the components are 10 parts of hydroquinone, 7 to 8 parts of 1,4-phenylenediboric acid, and 1 to 3 parts of concentrated sulfuric acid, respectively, by weight.

7. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 5, characterized in that: In step b, the added amounts of the components are 10 parts of phenol, 0.5 to 1 part of the boron-containing diphenol intermediate, 0.1 to 0.15 parts of sodium hydroxide, and 4.5 to 6.5 parts of formaldehyde, respectively, in parts by weight.

8. The method for preparing a viscose-based lightweight thermal insulation felt according to claim 1, characterized in that: In step S3, during the graphitization treatment, the cured fiber felt is heated to 300-310°C, kept warm for 5-10 minutes, and then heated to 500-505°C at a rate of 1-5°C / min. After keeping warm for 10-20 minutes, the temperature is again raised to 1200-1300°C, kept warm for 30-45 minutes, and then heated to 1800-1850°C again. After keeping warm for 0.5-1.5 hours, the temperature is raised to 2000-2100°C, and after the heat treatment for 1-2 hours, the temperature is cooled to room temperature with the furnace to obtain a viscose-based lightweight insulation felt.

9. A viscose-based lightweight thermal insulation felt prepared by the preparation method according to any one of claims 1 to 8.

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