Impregnant asphalt for carbon / carbon composite material as well as preparation method and application of impregnant asphalt

Abstract

The invention discloses impregnant asphalt for a carbon / carbon composite material and a preparation method and application of the impregnant asphalt. The preparation method comprises the following steps that S1, asphalt raw materials are put into a reaction kettle to be heated and melted, and the melted raw materials are conveyed into a first-stage reaction kettle to be subjected to condensation polymerization; s2, standing and settling a reaction product after the polycondensation reaction, cutting out a sinking material from the bottom, and taking an upper-layer light material as a master batch for impregnant asphalt; and S3, feeding the upper-layer light material into a second-stage reaction kettle, and carrying out condensation polymerization reaction to obtain the impregnant asphalt for the carbon / carbon composite material. The production process is efficient and stable, the quality is controllable, industrial production can be realized, the preparation cost is low, the preparation period is short, and the carbon / carbon composite material produced by using the impregnant asphalt is stable in microstructure and high in controllability.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt deep processing, and in particular relates to an impregnating agent asphalt for carbon / carbon composite materials and a preparation method and application thereof. Background Art

[0002] As a new type of high-temperature material with unique properties, carbon / carbon composites combine the excellent mechanical properties of fiber-reinforced composites and the excellent high-temperature properties of carbonaceous materials. They have a series of excellent properties such as high specific strength, specific modulus, good toughness, excellent strength retention rate at high temperatures, creep resistance and thermal shock resistance. It is the most ideal high-temperature material known in inert atmosphere and is widely used in aviation, aerospace and other fields.

[0003] At present, there are two main methods for preparing carbon / carbon composite materials: (1) Chemical vapor infiltration (CVD) and (2) Liquid phase impregnation and carbonization of resin or asphalt. Among them, the CVD method cannot be widely used due to its long cycle, high cost, low utilization rate of raw gas, unstable microstructure of matrix carbon, and difficulty in control. The liquid phase impregnation and carbonization of resin or asphalt is widely used because of its small shrinkage, easy graphitization, low price and abundant source of impregnating agent asphalt, and short production cycle. The core technology of preparing carbon / carbon composite materials by this method is to find a suitable impregnating agent asphalt. For example, the modified preparation method of a mosaic intermediate phase asphalt-based silicon-carbon composite electrode material proposed in Chinese Patent Publication No. CN115458726A and the modified preparation method of a wide-area intermediate phase asphalt-based silicon-carbon composite electrode material proposed in Chinese Patent Publication No. CN115513438A both focus on introducing the product carbon / carbon. The structure of the composite material, but did not introduce the preparation technology of the intermediate phase asphalt; for example, the Chinese patent publication No. CN115404092A proposed a method and device for continuously preparing the intermediate phase asphalt, which mainly introduced the use of a tubular reactor with no backmixing, segmented temperature control and high thermal efficiency to co-carbonize the refined coal tar and petroleum asphalt, and continuously prepare a spinnable intermediate phase asphalt with uniform molecular weight distribution, good flow properties and moderate softening point. This technology is not specifically used for impregnating asphalt for carbon / carbon composite materials; other relevant public documents and materials do not involve related research on impregnating asphalt for carbon / carbon composite materials. Summary of the invention

[0004] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide an impregnating asphalt for carbon / carbon composite materials, and a preparation method and application thereof, and to prepare an impregnating asphalt with stable quality, high yield, high mesophase content, high coking value and low impurity content by a two-stage polycondensation reaction; the production process of the impregnating asphalt of the present invention is efficient and stable, the quality is controllable, and industrial production can be realized, and the preparation cost is low and the preparation cycle is short. The carbon / carbon composite material produced using the impregnating asphalt has a stable microstructure and strong controllability.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A first aspect of the present invention provides a method for preparing an impregnating pitch for a carbon / carbon composite material, comprising the following steps:

[0007] S1, putting the asphalt raw material into a reactor to heat and melt it, and sending the melted raw material to a primary reactor for polycondensation reaction;

[0008] S2, after the reaction product after the polycondensation reaction is allowed to settle, the sinking material is cut out from the bottom, and the upper light material is used as a masterbatch for impregnating asphalt;

[0009] S3, sending the upper light material to the secondary reactor for polycondensation reaction to obtain impregnating agent asphalt for carbon / carbon composite materials.

[0010] Preferably, in step S1, the asphalt raw material is selected from petroleum asphalt, coal tar asphalt, or a mixture of the two.

[0011] Preferably, in step S1, the asphalt raw material has a softening point of 120±5°C, an ash content of ≤10000ppm, and a sulfur content of ≤1wt%.

[0012] Preferably, in step S1:

[0013] The heating temperature is 200-220°C: and / or

[0014] The polycondensation reaction is carried out in an anaerobic environment, the reaction temperature is 360-400° C., the rotation speed during the reaction is 120-150 rpm, and the reaction time is 3-10 hours.

[0015] Preferably, in step S2, the static sedimentation time is 5 to 10 hours.

[0016] Preferably, in step S2, the sinking material is 10-30wt% of the total amount of the reaction product.

[0017] Preferably, in step S3, the polycondensation reaction is carried out in an anaerobic environment, the reaction temperature is 390-440° C., the rotation speed during the reaction is 110-130 rpm, and the reaction time is 4-8 h.

[0018] The second aspect of the present invention provides an impregnating pitch for a carbon / carbon composite material, wherein the impregnating pitch for a carbon / carbon composite material is obtained according to the preparation method of the impregnating pitch for a carbon / carbon composite material described in the first aspect of the present invention.

[0019] Preferably, the impregnating agent asphalt has a mesophase content of ≥35 vol%, a coking value of ≥70%, an ash content of ≤350 ppm, and a viscosity at 300° C. of ≥85 Pa·s.

[0020] The third aspect of the present invention provides a use of the impregnating agent pitch for carbon / carbon composite materials as described in the second aspect of the present invention in the preparation of carbon / carbon composite materials.

[0021] The impregnating agent asphalt for carbon / carbon composite materials provided by the present invention and its preparation method and application have the following characteristics:

[0022] Beneficial effects:

[0023] 1. The present invention adopts a two-stage polycondensation reaction to prepare an impregnating agent asphalt with stable quality, high yield, high mesophase content, high coking value and low impurity content; the production process of the impregnating agent asphalt of the present invention is efficient and stable, the quality is controllable, industrial production can be realized, and the preparation cost is low and the preparation cycle is short;

[0024] 2. The carbon / carbon composite material produced by the impregnating agent asphalt prepared by the present invention has a stable microstructure and strong controllability, which can solve the problem that the microstructure of the matrix carbon in the current domestic preparation of carbon / carbon composite materials is unstable and difficult to control. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0026] Since there is no technology specifically studying impregnating asphalt for carbon / carbon composite materials in the prior art, and the microstructure of the matrix carbon used to prepare carbon / carbon composite materials in China is unstable and difficult to control, the present invention specifically studies impregnating asphalt for carbon / carbon composite materials to solve the technical gap of impregnating asphalt for carbon / carbon composite materials in the prior art.

[0027] The present invention discloses an impregnating agent asphalt for carbon / carbon composite materials and a preparation method and application thereof, comprising the following steps:

[0028] S1, putting the asphalt raw material into a reactor to heat and melt it, and sending the melted raw material to a primary reactor for polycondensation reaction;

[0029] Specifically, one or a mixture of petroleum asphalt, coal tar asphalt or both is selected as the asphalt raw material; the raw material requirements are as follows: softening point of 123°C, ash content ≤4000ppm, sulfur content ≤0.6wt%; in a specific embodiment, petroleum asphalt is prepared using FCC oil slurry, and coal tar asphalt is prepared using coal tar.

[0030] The asphalt raw material selected above is put into a reactor and heated to 200-220°C to melt the raw material; the melted raw material is then pumped into a primary reactor by a delivery pump, and a condensation reaction is carried out in an anaerobic environment at 360-400°C and a rotation speed of 120-150rpm, and the reaction time is 3-10h.

[0031] S2, after the reaction product after the polycondensation reaction is allowed to settle, the sinking material is cut out from the bottom, and the upper light material is used as a masterbatch for impregnating asphalt;

[0032] Specifically, the reaction product after the condensation reaction obtained in step S1 is allowed to settle for 5 to 10 hours, and then the sinking material is cut out from the bottom of the reaction product. The sinking material is about 10 to 30 wt% of the total amount of the reaction product. The cut-off material is used as a by-product, and the upper layer material is used as a masterbatch for impregnating agent asphalt.

[0033] S3, sending the upper light material to the secondary reactor for polycondensation reaction to obtain impregnating agent asphalt for carbon / carbon composite materials.

[0034] Specifically, the upper light material (i.e., the masterbatch for impregnating asphalt) is delivered to the secondary reactor by a delivery pump, and a condensation reaction is carried out in an anaerobic environment at 390-440°C and a rotation speed of 110-130 rpm. The reaction time is 4-8 hours, and after the reaction product is cooled, the impregnating asphalt for carbon / carbon composite materials is obtained.

[0035] According to the above preparation method, an impregnating agent pitch for carbon / carbon composite materials is obtained, wherein the impregnating agent pitch has an intermediate phase content ≥35 vol%, a coking value ≥70%, an ash content ≤350 ppm, and a viscosity at 300°C ≥85 Pa·s.

[0036] The present invention also provides a use of the impregnating agent pitch for carbon / carbon composite materials as described above in the preparation of carbon / carbon composite materials. The carbon / carbon composite materials produced by the impregnating agent pitch have stable microstructure and strong controllability.

[0037] The impregnating agent asphalt for the carbon / carbon composite material of the present invention and its preparation method and application are further introduced below with reference to specific examples.

[0038] Example 1

[0039] The preparation method of the impregnating agent pitch for the carbon / carbon composite material in this embodiment is as follows:

[0040] 600 kg of petroleum asphalt was put into a reactor and heated to 120°C to melt it, and then it was sent to a primary reactor by a delivery pump, and polycondensed for 3 hours under the conditions of anaerobic, 360°C, and 120 rpm; the reaction product after the polycondensation reaction was allowed to settle for 8 hours, and then 180 kg of material was discharged from the bottom of the reactor, and the discharge was stopped, and the remaining upper light material was pumped into a secondary reactor by a delivery pump, and polycondensed for 4 hours under the conditions of anaerobic, 390°C, and 110 rpm, and then cooled and formed to obtain an impregnating agent asphalt for carbon / carbon composite materials, and its product properties are shown in Table 1;

[0041] Example 2

[0042] The preparation method of the impregnating agent pitch for the carbon / carbon composite material in this embodiment is as follows:

[0043] 500 kg of coal-based asphalt was put into a reactor and heated to 210°C to melt it, and then it was sent to a primary reactor by a delivery pump, and polycondensed for 6 hours under the conditions of anaerobic, 380°C, and 140 rpm; the reaction product after the polycondensation reaction was allowed to settle for 9 hours, and then 100 kg of material was discharged from the bottom of the reactor, and the discharge was stopped, and the remaining upper light material was pumped into a secondary reactor by a delivery pump, and polycondensed for 6 hours under the conditions of anaerobic, 410°C, and 120 rpm, and then cooled and formed to obtain an impregnating agent asphalt for carbon / carbon composite materials, and its product properties are shown in Table 1;

[0044] Example 3

[0045] The preparation method of the impregnating agent pitch for the carbon / carbon composite material in this embodiment is as follows:

[0046] 400 kg of coal tar pitch and 200 kg of petroleum asphalt were put into a reactor and heated to 200 ° C to melt them, and then they were sent to a primary reactor by a delivery pump, and polycondensed for 5 hours at 370 ° C and 150 rpm in anoxic condition; the reaction product after the polycondensation reaction was allowed to settle for 8 hours, and then 90 kg of material was discharged from the bottom of the reactor, and the discharge was stopped, and the remaining upper light material was pumped into a secondary reactor by a delivery pump, and polycondensed for 5 hours at 400 ° C and 130 rpm in anoxic condition, and then cooled and formed to obtain an impregnating agent asphalt for carbon / carbon composite materials, and its product properties are shown in Table 1;

[0047] Example 4

[0048] The preparation method of the impregnating agent pitch for the carbon / carbon composite material in this embodiment is as follows:

[0049] 180kg of petroleum asphalt and 420kg of coal tar asphalt were put into a reactor and heated to 200°C to melt them, and then they were sent to a primary reactor by a delivery pump, and polycondensed for 9 hours at 380°C and 130rpm in anoxic condition; the reaction product after the polycondensation reaction was allowed to settle for 10 hours, and then 120kg of material was discharged from the bottom of the reactor, and the discharge was stopped, and the remaining upper light material was pumped into a secondary reactor by a delivery pump, and polycondensed for 7 hours at 430°C and 110rpm in anoxic condition, and then cooled and formed to obtain an impregnating agent asphalt for carbon / carbon composite materials, and its product properties are shown in Table 1;

[0050] Table 1 Properties of the impregnating agent asphalt used for the carbon / carbon composite material prepared in Example

[0051]

[0052] As shown in Table 1, the mesophase content of the impregnating agent pitch used for the carbon / carbon composite material prepared in the embodiment of the present invention is between 35 and 55%, the coking value is between 70 and 85%, the ash content is between 120 and 320 ppm, the viscosity at 300°C is between 85 and 100 Pa·s, and no insoluble matter is detected.

[0053] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing an impregnating asphalt for a carbon / carbon composite material, characterized in that: The following steps are involved: S1, putting the asphalt raw material into a reactor to heat and melt it, and sending the melted raw material to a primary reactor for polycondensation reaction; S2, after the reaction product after the polycondensation reaction is allowed to settle, the sinking material is cut out from the bottom, and the upper light material is used as a masterbatch for impregnating asphalt; S3, sending the upper light material to the secondary reactor for polycondensation reaction to obtain impregnating agent asphalt for carbon / carbon composite materials.

2. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 1, characterized in that: In the step S1, the asphalt raw material is selected from petroleum asphalt, coal tar asphalt, or a mixture of the two.

3. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 2, characterized in that: In the step S1, the asphalt raw material has a softening point of 120±5°C, an ash content of ≤10000ppm, and a sulfur content of ≤1wt%.

4. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 1, characterized in that: In step S1: The heating temperature is 200-220°C: and / or The polycondensation reaction is carried out in an anaerobic environment, the reaction temperature is 360-400° C., the rotation speed during the reaction is 120-150 rpm, and the reaction time is 3-10 hours.

5. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 1, characterized in that: In the step S2, the static sedimentation time is 5 to 10 hours.

6. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 1, characterized in that: In the step S2, the sinking material is 10-30wt% of the total amount of the reaction product.

7. The method for preparing an impregnating pitch for a carbon / carbon composite material according to claim 1, characterized in that: In the step S3, the polycondensation reaction is carried out in an anaerobic environment, the reaction temperature is 390-440° C., the rotation speed during the reaction is 110-130 rpm, and the reaction time is 4-8 hours.

8. An impregnating pitch for carbon / carbon composite materials, characterized in that: The impregnating agent pitch for carbon / carbon composite materials is obtained according to the preparation method of the impregnating agent pitch for carbon / carbon composite materials according to any one of claims 1 to 7.

9. The impregnating agent pitch for carbon / carbon composite material according to claim 8, characterized in that The impregnating agent asphalt has a mesophase content of ≥35 vol%, a coking value of ≥70%, an ash content of ≤350 ppm, and a viscosity at 300° C. of ≥85 Pa·s.

10. Use of the impregnating pitch for carbon / carbon composite materials as claimed in claim 8 or 9 in the preparation of carbon / carbon composite materials.

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