Preparation method for modified cryptocrystalline graphite sound insulation rubber

Abstract

Provided is a preparation method for a modified cryptocrystalline graphite sound insulation rubber, which preparation method comprises the following steps: weighing a certain amount of cryptocrystalline graphite, adding a solution I, subjecting the resulting mixture to a pre-oxidation intercalation treatment, adding a strong acid thereto after the pre-oxidation intercalation treatment is finished, so as to perform secondary oxidation intercalation, and collecting a solid product I after the reaction is finished; washing the solid product I until neutral, and collecting a solid product II; sequentially weighing a natural rubber, an auxiliary and the solid product II, adding same into an internal mixer for internal mixing, vulcanizing same after internal mixing is finished, and collecting a solid product III after the vulcanization; and aging the solid product III under a constant temperature for 24 h, and cutting same, so as to obtain a sound insulation rubber. A sound insulation rubber material having a good effect is prepared by means of the processes of two instances of oxidation intercalation modification, and blending, internal mixing, vulcanization, etc. of the modified cryptocrystalline graphite, the natural rubber and the auxiliary. The mechanism is clear, the process is simple, and the product is good, has broad use prospects, and is suitable for industrial popularization.

Description

A method for preparing modified cryptocrystalline graphite sound-insulating rubber Technical Field

[0001] This invention relates to the field of rubber composite materials technology, and specifically to a method for preparing modified cryptocrystalline graphite sound-insulating rubber. Background Technology

[0002] Noise pollution, as a specific type of environmental pollution, is widespread in the transportation and construction industries, as well as in daily life, significantly impacting human physical and mental health, and affecting the operational stability and lifespan of mechanical equipment. Rubber, as an excellent polymeric sound insulation material, is lighter and easier to process compared to traditional sound insulation materials. However, rubber suffers from low areal density, a small damping factor, poor mechanical properties, and poor processability, limiting its large-scale application in the sound insulation material field. To effectively address these issues, functional reinforcing fillers need to be added to the rubber system to improve its application and processing performance.

[0003] Currently, functional reinforcing fillers for sound-insulating rubber can be divided into four main categories: carbon black, kaolin, novel fillers, and crystalline graphite. Carbon black, including carbon black and silica, suffers from drawbacks such as high filler content and severe dust pollution during processing. Kaolin, including montmorillonite, has limited reinforcing effect on rubber properties. Novel fillers, including graphene and carbon nanotubes, are expensive, prone to agglomeration in rubber, and have poor dispersibility. Crystalline graphite, when used as a filler, has disadvantages such as low surface activity and the need for small particle sizes to achieve its reinforcing properties.

[0004] Cryptocrystalline graphite, when used as a rubber filler, has similar functions to crystalline graphite, reinforcing rubber, providing lubrication, and improving chemical stability. However, compared to crystalline graphite, its finer particle size and higher surface activity can effectively improve the shortcomings of crystalline graphite as a rubber filler. At the same time, as a natural graphite resource, cryptocrystalline graphite is abundant, widely distributed, and inexpensive. In terms of rubber performance and sound insulation performance, the reinforcing effect can be further improved by modifying cryptocrystalline graphite.

[0005] The prior art CN107446190A discloses "a lightweight tear-resistant microcrystalline graphite rubber composite material and its preparation method". This method uses microcrystalline graphite to reduce the specific gravity of the composite material and improve its tear resistance. It uses fillers to stabilize product specifications and reduce material costs, and uses accelerators to promote the compatibility of the composite material, thereby improving the overall performance of the rubber composite material. However, it does not study the sound insulation performance.

[0006] Beijing Rubber Industry Research and Design Institute Co., Ltd. mainly studied the influence of cryptocrystalline graphite from different mining areas on the physical properties of natural rubber under different particle sizes. At the same time, it used cryptocrystalline graphite to replace part of carbon black and nitrile rubber to prepare rubber composites. The tensile strength and tear strength of the composites were increased by 10.8% and 5.3% respectively compared with rubber without cryptocrystalline graphite. However, the sound insulation performance of the composites was not considered.

[0007] Therefore, in response to the lack of high-value-added applications for cryptocrystalline graphite and the insufficient research on the preparation methods and performance of cryptocrystalline graphite sound-insulating rubber, this invention provides a method for preparing modified cryptocrystalline graphite sound-insulating rubber. This method uses modified cryptocrystalline graphite to replace traditional fillers in the preparation of sound-insulating rubber, aiming to solve the problems of cryptocrystalline graphite modification and its composite with rubber, expand the application of cryptocrystalline graphite in the field of sound wave absorption, and provide new ideas for the high-value-added applications of cryptocrystalline graphite. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing modified cryptocrystalline graphite sound-insulating rubber, filling a gap in the current technology.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for preparing modified cryptocrystalline graphite sound-insulating rubber includes the following steps:

[0011] (1) Weigh cryptocrystalline graphite, add it to solution I, stir and carry out pre-oxidation intercalation treatment. After the pre-oxidation intercalation reaction is completed, add strong acid of the same weight as cryptocrystalline graphite for secondary oxidation intercalation. After the reaction is completed, collect solid product I.

[0012] (2) Wash solid product I until the product is neutral, and collect solid product II;

[0013] (3) Weigh natural rubber, stearic acid, zinc oxide, accelerator TMTD, accelerator DM, accelerator CZ, sulfur, solid product II, and antioxidant 4010NA in sequence and add them to the internal mixer. Control the temperature and mix them. After the mixing is completed, place the rubber compound in a flat vulcanizing machine and control the temperature to vulcanize it. Collect solid product III after vulcanization.

[0014] (4) After aging the solid product Ⅲ under constant temperature conditions for 24 hours, modified cryptocrystalline graphite sound insulation rubber is obtained.

[0015] Preferably, in step (1), the fixed carbon content of the cryptocrystalline graphite is greater than 80%.

[0016] Preferably, in step (1), solution I is a solution prepared by mass ratio of one or more of hydrogen peroxide, concentrated sulfuric acid, concentrated nitric acid, sodium dichromate, and acetic anhydride, and the pre-oxidation intercalation time is 60 to 120 minutes.

[0017] More preferably, solution I is a solution prepared by mixing 30% hydrogen peroxide and concentrated sulfuric acid at a mass ratio of 1:10, and the pre-oxidation intercalation time is 90 minutes.

[0018] Preferably, in step (1), the strong acid added during the secondary oxidation intercalation is concentrated sulfuric acid or concentrated nitric acid, and the secondary oxidation intercalation time is 90 to 150 minutes.

[0019] More preferably, in step (1), the strong acid added during the secondary oxidation intercalation is concentrated nitric acid, and the secondary oxidation intercalation time is 120 minutes.

[0020] Preferably, in step (2), the washing method of the solid product I is selected from one of rinsing with clean water, ultrasonic washing, and centrifugal washing, and the washing endpoint is determined by the neutrality of the washing water.

[0021] More preferably, in step (2), the solid product I is washed by ultrasonic washing.

[0022] Preferably, in step (3), by weight, there are 100 parts of natural rubber, 0.8 to 1.0 parts of stearic acid, 1 to 3.5 parts of zinc oxide, 0.1 to 0.4 parts of accelerator TMTD, 0.3 to 1.2 parts of accelerator DM, 0 to 1 part of accelerator CZ, 0.5 to 2 parts of sulfur, 20 to 60 parts of solid product II, and 0.2 to 1.2 parts of antioxidant 4010NA.

[0023] More preferably, in step (3), by weight, there are 100 parts of natural rubber, 1.0 parts of stearic acid, 3.5 parts of zinc oxide, 0.3 parts of accelerator TMTD, 0.9 parts of accelerator DM, 0.5 parts of accelerator CZ, 1.5 parts of sulfur, 30-50 parts of solid product II, and 1 part of antioxidant 4010NA.

[0024] Preferably, in step (3), the mixing temperature is 60-100°C and the mixing time is 5-20 minutes.

[0025] More preferably, in step (3), the mixing temperature is 80°C and the mixing time is 10 minutes.

[0026] Preferably, in step (3), the vulcanization temperature is 120-180°C and the vulcanization time is 10-15 minutes.

[0027] More preferably, in step (3), the vulcanization temperature is 140°C and the vulcanization time is 13 minutes.

[0028] Preferably, in step (4), the constant temperature condition is 20–32°C.

[0029] More preferably, in step (4), the constant temperature condition is 21-25°C.

[0030] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0031] 1. This invention improves the surface properties of cryptocrystalline graphite through two oxidation intercalation modifications, enhancing its dispersibility and flexibility, which is beneficial for its subsequent interfacial composite with rubber.

[0032] 2. This invention effectively solves the problem of preferred orientation when cryptocrystalline graphite is compounded with natural rubber and additives by two oxidation intercalation modifications of cryptocrystalline graphite and blending and mixing them. This improves the stability of the interface between cryptocrystalline graphite and natural rubber, which is beneficial to improving the mechanical properties and processing performance of sound insulation rubber.

[0033] 3. This invention addresses the problems of small particle size, numerous surface impurities, and high surface activity of cryptocrystalline graphite. It creatively prepares a high-performance sound-insulating rubber material through a process involving two-stage oxidation intercalation modification, blending and mixing the modified cryptocrystalline graphite with natural rubber and additives, and vulcanization. The mechanism is clear, the process is simple, the product is excellent, and it has broad application prospects and is suitable for industrial promotion. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0035] Figure 1 is a process flow diagram of Embodiment 1 of the present invention;

[0036] Figure 2 is a sound insulation test diagram of Embodiments 1-3 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0037] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0038] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0039] Example 1

[0040] Referring to Figures 1 and 2, this embodiment provides a method for preparing modified cryptocrystalline graphite sound-insulating rubber, including the following steps:

[0041] (1) Prepare solution I by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid at a mass ratio of 1:10. Add cryptocrystalline graphite with a fixed carbon content of 83.32% to solution I at a solid-liquid ratio of 1:4 and stir for 90 min for pre-oxidation intercalation treatment. After the pre-oxidation intercalation reaction is completed, add concentrated nitric acid of the same weight as cryptocrystalline graphite for secondary oxidation intercalation for 120 min. After the reaction is completed, collect solid product I.

[0042] (2) Ultrasonic washing was performed on solid product I until the product was neutral. The solid product was collected and recorded as solid product II.

[0043] (3) Weigh out 100 parts of natural rubber, 1.0 part of stearic acid, 3.5 parts of zinc oxide, 0.3 parts of accelerator TMTD, 0.9 parts of accelerator DM, 0.5 parts of accelerator CZ, 1.5 parts of sulfur, 30 parts of solid product II, and 1 part of antioxidant 4010NA in the following order by weight and add them to the internal mixer. Set the temperature to 80℃ and the mixing time to 10min. After the mixing is completed, put the discharged rubber into a flat vulcanizing machine for vulcanization treatment. The vulcanization time is 13min and the temperature is 140℃. After the vulcanization is completed, collect solid product III.

[0044] (4) After aging the solid product Ⅲ at a constant temperature of 23℃ for 24h, modified cryptocrystalline graphite sound insulation rubber was obtained.

[0045] Example 2

[0046] Referring to Figure 2, this embodiment provides a method for preparing modified cryptocrystalline graphite sound-insulating rubber, including the following steps:

[0047] (1) Prepare solution I by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid at a mass ratio of 1:10. Add cryptocrystalline graphite with a fixed carbon content of 83.32% to solution I at a solid-liquid ratio of 1:4 and stir for 90 min for pre-oxidation intercalation treatment. After the pre-oxidation intercalation reaction is completed, add concentrated nitric acid of the same weight as cryptocrystalline graphite for secondary oxidation intercalation for 120 min. After the reaction is completed, collect solid product I.

[0048] (2) Ultrasonic washing was performed on solid product I until the product was neutral. The solid product was collected and recorded as solid product II.

[0049] (3) Weigh out 100 parts of natural rubber, 1.0 part of stearic acid, 3.5 parts of zinc oxide, 0.3 parts of accelerator TMTD, 0.9 parts of accelerator DM, 0.5 parts of accelerator CZ, 1.5 parts of sulfur, 40 parts of solid product II, and 1 part of antioxidant 4010NA in sequence by weight and add them to the internal mixer. Set the temperature to 80℃ and the mixing time to 10min. After the mixing is completed, put the discharged rubber into a flat vulcanizing machine for vulcanization treatment. The vulcanization time is 13min and the temperature is 140℃. After the vulcanization is completed, collect solid product III.

[0050] (4) After aging the solid product Ⅲ at a constant temperature of 23℃ for 24h, modified cryptocrystalline graphite sound insulation rubber was obtained.

[0051] Example 3

[0052] Referring to Figure 2, this embodiment provides a method for preparing modified cryptocrystalline graphite sound-insulating rubber, including the following steps:

[0053] (1) Prepare solution I by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid at a mass ratio of 1:10. Add cryptocrystalline graphite with a fixed carbon content of 83.32% to solution I at a solid-liquid ratio of 1:4 and stir for 90 min for pre-oxidation intercalation treatment. After the pre-oxidation intercalation reaction is completed, add concentrated nitric acid of the same weight as cryptocrystalline graphite for secondary oxidation intercalation for 120 min. After the reaction is completed, collect solid product I.

[0054] (2) Ultrasonic washing was performed on solid product I until the product was neutral. The solid product was collected and recorded as solid product II.

[0055] (3) Weigh out 100 parts of natural rubber, 1.0 part of stearic acid, 3.5 parts of zinc oxide, 0.3 parts of accelerator TMTD, 0.9 parts of accelerator DM, 0.5 parts of accelerator CZ, 1.5 parts of sulfur, 50 parts of solid product II, and 1 part of antioxidant 4010NA in sequence by weight and add them to the internal mixer. Set the temperature to 80℃ and the mixing time to 10min. After the mixing is completed, put the discharged rubber into a flat vulcanizing machine for vulcanization treatment. The vulcanization time is 13min and the temperature is 140℃. After the vulcanization is completed, collect solid product III.

[0056] (4) After aging the solid product Ⅲ at a constant temperature of 23℃ for 24h, modified cryptocrystalline graphite sound insulation rubber was obtained.

[0057] Comparative Example 1

[0058] Referring to Figure 2, this comparative example is based on the above-described Example 1, and the similarities with Example 1 will not be repeated.

[0059] In this comparative example, 30 parts of montmorillonite were used as rubber filler instead of modified cryptocrystalline graphite; all other aspects were the same as in Example 1.

[0060] Comparative Example 2

[0061] Referring to Figure 2, this comparative example is based on the above-described Example 2, and the similarities with Example 2 will not be repeated.

[0062] In this comparative example, 40 parts of carbon black were used as rubber filler instead of modified cryptocrystalline graphite; otherwise, they were the same as in Example 2.

[0063] The tensile properties, tear strength, Shore hardness, effective sound insulation frequency band, and peak sound insulation of the sound insulation rubber prepared in Examples 1, 2, and 3, and Comparative Examples 1 and 2 were tested respectively. The test results are shown in Table 1, and the sound insulation test graph is shown in Figure 2.

[0064] Table 1

[0065] Table 1 shows that Comparative Example 1 did not use modified cryptocrystalline graphite as filler but used 30 parts of montmorillonite as rubber filler. The mechanical properties of the sound-insulating rubber were lower than those of Example 1, and the sound insulation was only higher than 10 dB in the range of 1004 Hz to 1600 Hz. Comparative Example 2 did not use modified cryptocrystalline graphite but used 40 parts of carbon black as rubber filler. Its mechanical properties were not much different from those of Example 2, but the sound insulation was only higher than 10 dB in the range of 880 Hz to 1600 Hz. Comparing Examples 1, 2 and 3, Example 2 had the best mechanical properties and sound insulation. The sound insulation was higher than 10 dB in the range of 300 Hz to 1600 Hz, which means it achieved 90% sound insulation.

[0066] In summary, this invention improves the surface properties of cryptocrystalline graphite through two-stage oxidative intercalation modification, enhancing its dispersibility and flexibility, which is beneficial for its subsequent interfacial composite with rubber. Furthermore, this invention effectively solves the preferential orientation problem when cryptocrystalline graphite is composited with natural rubber by blending and mixing the modified cryptocrystalline graphite with natural rubber and additives through two-stage oxidative intercalation modification, improving the stability of the interface between cryptocrystalline graphite and natural rubber, and thus enhancing the mechanical and processing properties of the sound-insulating rubber. Addressing the problems of small particle size, numerous surface impurities, and high surface activity of cryptocrystalline graphite, this invention creatively prepares a high-performance sound-insulating rubber material through a process involving two-stage oxidative intercalation modification, blending and mixing the modified cryptocrystalline graphite with natural rubber and additives, and vulcanization. The mechanism is clear, the process is simple, the product is excellent, and it has broad application prospects, making it suitable for industrial promotion.

[0067] The preferred modification and preparation process conditions in the above embodiments are obtained based on a large number of exploratory experiments and scientific experimental design of single variable and orthogonal experiments. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0068] The specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0069] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

[0070] In summary, the above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing modified cryptocrystalline graphite sound-insulating rubber, characterized in that, Includes the following steps: (1) Weigh cryptocrystalline graphite, add it to solution I, stir and carry out pre-oxidation intercalation treatment. After the pre-oxidation intercalation reaction is completed, add strong acid of the same weight as cryptocrystalline graphite for secondary oxidation intercalation. After the reaction is completed, collect solid product I. (2) Wash solid product I until the product is neutral, and collect solid product II; (3) Weigh natural rubber, stearic acid, zinc oxide, accelerator TMTD, accelerator DM, accelerator CZ, sulfur, solid product II, and antioxidant 4010NA in sequence and add them to the internal mixer. Control the temperature and mix them. After the mixing is completed, place the rubber compound in a flat vulcanizing machine and control the temperature to vulcanize it. Collect solid product III after vulcanization. (4) After aging the solid product Ⅲ under constant temperature conditions for 24 hours, modified cryptocrystalline graphite sound insulation rubber is obtained.

2. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (1), the fixed carbon content of the cryptocrystalline graphite is greater than 80%.

3. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (1), solution I is a solution prepared by mass ratio of one or more of hydrogen peroxide, concentrated sulfuric acid, concentrated nitric acid, sodium dichromate, and acetic anhydride, and the pre-oxidation intercalation time is 60 to 120 minutes.

4. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (1), the strong acid added during the secondary oxidation intercalation is concentrated sulfuric acid or concentrated nitric acid, and the secondary oxidation intercalation time is 90 to 150 minutes.

5. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (2), the washing method of the solid product I is selected from one of rinsing with clean water, ultrasonic washing, and centrifugal washing, and the washing endpoint is determined by the neutrality of the washing water.

6. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (3), by weight, there are 100 parts of natural rubber, 0.8 to 1.0 parts of stearic acid, 1 to 3.5 parts of zinc oxide, 0.1 to 0.4 parts of accelerator TMTD, 0.3 to 1.2 parts of accelerator DM, 0 to 1 part of accelerator CZ, 0.5 to 2 parts of sulfur, 20 to 60 parts of solid product II, and 0.2 to 1.2 parts of antioxidant 4010NA.

7. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (3), the mixing temperature is 60-100℃ and the mixing time is 5-20 minutes.

8. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (3), the vulcanization temperature is 120-180°C and the vulcanization time is 10-15 minutes.

9. The method for preparing a modified cryptocrystalline graphite sound-insulating rubber according to claim 1, characterized in that, In step (4), the constant temperature condition is 20-32℃.

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