Preparation method of modified cryptocrystalline graphite sound insulation rubber

Abstract

The invention discloses a preparation method of modified cryptocrystalline graphite sound insulation rubber, which comprises the following steps: weighing a certain amount of cryptocrystalline graphite, adding a solution I, carrying out pre-oxidation intercalation treatment, adding strong acid after the pre-oxidation intercalation treatment is finished, carrying out secondary oxidation intercalation, and collecting a solid product I after the reaction is finished; washing the solid product I to be neutral, and collecting a solid product II; sequentially weighing natural rubber, an auxiliary agent and the solid product II, adding into an internal mixer for internal mixing, vulcanizing after internal mixing is finished, and collecting a solid product III after vulcanizing; aging the solid product III under a constant temperature condition for 24 hours, and cutting to obtain the sound insulation rubber. The sound insulation rubber material with a good effect is prepared through the processes of twice oxidation intercalation modification, blending and banburying of the modified cryptocrystalline graphite, the natural rubber and the auxiliaries, vulcanization and the like, the mechanism is clear, the process is simple, the product is excellent, the use prospect is wide, and the sound insulation rubber material is suitable for industrial popularization.

Description

Technical Field

[0001] The invention relates to the technical field of rubber composite materials, and in particular to a method for preparing modified cryptocrystalline graphite sound insulation rubber. Background Art

[0002] Noise pollution, as a special type of environmental pollution, is widely found in the transportation industry, the construction industry, and daily life, greatly affecting human physical and mental health, the operating stability and service life of mechanical equipment. Rubber, as an excellent polymer sound insulation material, has the characteristics of light weight and easy processing compared to traditional sound insulation materials. However, rubber has problems such as low surface density, small damping factor, poor mechanical properties, and poor processability, which limit its large-scale application in the field of sound insulation materials. In order to effectively solve the above problems, functional reinforcing fillers need to be added to the rubber system to improve its application and processing performance.

[0003] At present, the functional reinforcing fillers of sound insulation rubber can be divided into four categories, namely carbon black, clay, new fillers and crystalline graphite. Among them, carbon black includes carbon black and white carbon black, and its disadvantages are large filling amount and serious dust pollution during processing; clay includes montmorillonite, etc., and its disadvantage is limited reinforcement effect on rubber performance; new fillers include graphene, carbon nanotubes, etc., and their disadvantages are expensive, easy to agglomerate in rubber, and poor dispersion; the disadvantage of crystalline graphite as a filler is that its surface activity is low and a smaller particle size is required to exert its reinforcing properties.

[0004] When used as a rubber filler, cryptocrystalline graphite has similar functions to crystalline graphite. It can reinforce rubber, bring lubricity and improve chemical stability. However, compared with crystalline graphite, its fine particle size and higher surface activity can effectively improve the shortcomings of crystalline graphite as a rubber filler. At the same time, cryptocrystalline graphite is a natural graphite resource with abundant reserves, wide distribution and low price. The reinforcement effect can be further improved in terms of rubber performance and sound insulation performance by modifying cryptocrystalline graphite.

[0005] The prior art CN107446190A discloses "a lightweight tear-resistant microcrystalline graphite, a lightweight tear-resistant microcrystalline graphite rubber composite material and a preparation method thereof". This method uses microcrystalline graphite to reduce the specific gravity of the composite material while improving the tear strength of the composite material, 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, but no research has been done on the sound insulation performance.

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

[0007] Therefore, in view of the lack of high value-added applications of cryptocrystalline graphite, the lack of preparation methods and performance research of cryptocrystalline graphite sound insulation rubber, the present invention provides a method for preparing modified cryptocrystalline graphite sound insulation rubber, a method for preparing sound insulation rubber using modified cryptocrystalline graphite instead of traditional fillers, and is committed to solving the problems of cryptocrystalline graphite modification and its composite with rubber, expanding the application of cryptocrystalline graphite in the field of sound wave absorption, and providing new ideas for high value-added applications of cryptocrystalline graphite. Summary of the invention

[0008] The purpose of the invention is to provide a method for preparing a modified cryptocrystalline graphite sound insulation rubber to fill the gap in the current technology.

[0009] The purpose of the present invention is achieved through the following technical solutions: A method for preparing modified cryptocrystalline graphite sound insulation rubber comprises the following steps: (1) Weigh cryptocrystalline graphite, add solution I, stir and perform pre-oxidation intercalation treatment, add a strong acid of the same weight as the cryptocrystalline graphite for secondary oxidation intercalation after the pre-oxidation intercalation reaction is completed, and collect the solid product I after the reaction is completed; (2) washing the solid product I until the product is neutral, and collecting the 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 order, add them to an internal mixer and control the temperature for internal mixing. After the internal mixing is completed, place the rubber material in a flat vulcanizer and control the temperature for vulcanization. After vulcanization, collect the solid product III; (4) The solid product III is aged at a constant temperature for 24 hours to obtain a modified cryptocrystalline graphite sound insulation rubber.

[0010] Preferably, in step (1), the fixed carbon content of the cryptocrystalline graphite is greater than 80%.

[0011] Preferably, in step (1), the solution I is a solution of one or more combinations of hydrogen peroxide, concentrated sulfuric acid, concentrated nitric acid, sodium red alum, and acetic anhydride configured in a mass ratio, and the pre-oxidation intercalation time is 60 to 120 minutes.

[0012] Further preferably, the solution I is a solution prepared by mixing 30% hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 1:10, and the pre-oxidation intercalation time is 90 minutes.

[0013] Preferably, in step (1), the strong acid added in the secondary oxidation intercalation is concentrated sulfuric acid or concentrated nitric acid, and the secondary oxidation intercalation time is 90 to 150 minutes.

[0014] Further preferably, in step (1), the strong acid added in the secondary oxidation intercalation is concentrated nitric acid, and the secondary oxidation intercalation time is 120 minutes.

[0015] Preferably, in step (2), the solid product I is washed by a method selected from the group consisting of water rinsing, ultrasonic washing, and centrifugal washing, and the washing endpoint is determined by whether the washing water is neutral.

[0016] Further preferably, in step (2), the solid product I is washed by ultrasonic washing.

[0017] Preferably, in step (3), in parts by weight, natural rubber is 100 parts, stearic acid is 0.8-1.0 parts, zinc oxide is 1-3.5 parts, accelerator TMTD is 0.1-0.4 parts, accelerator DM is 0.3-1.2 parts, accelerator CZ is 0-1 parts, sulfur is 0.5-2 parts, solid product II is 20-60 parts, and antioxidant 4010NA is 0.2-1.2 parts.

[0018] Further preferably, in step (3), in parts by weight, natural rubber is 100 parts, stearic acid is 1.0 parts, zinc oxide is 3.5 parts, accelerator TMTD is 0.3 parts, accelerator DM is 0.9 parts, accelerator CZ is 0.5 parts, sulfur is 1.5 parts, solid product II is 30-50 parts, and antioxidant 4010NA is 1 part.

[0019] Preferably, in step (3), the banburying temperature is 60-100° C., and the banburying time is 5-20 minutes.

[0020] Further preferably, in step (3), the banburying temperature is 80° C. and the banburying time is 10 minutes.

[0021] Preferably, in step (3), the vulcanization temperature is 120-180° C., and the vulcanization time is 10-15 minutes.

[0022] Further preferably, in step (3), the vulcanization temperature is 140° C. and the vulcanization time is 13 minutes.

[0023] Preferably, in step (4), the constant temperature condition is 20-32°C.

[0024] More preferably, in step (4), the constant temperature condition is 21-25°C.

[0025] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. The present invention improves the surface properties of cryptocrystalline graphite through two oxidation intercalation modifications, enhances its dispersibility and flexibility, and is beneficial to its subsequent interface composite with rubber; 2. The present invention uses twice oxidation intercalation to modify cryptocrystalline graphite and mix it with natural rubber and additives, which effectively solves the problem of preferred orientation when cryptocrystalline graphite is compounded with natural rubber, improves the stability of the interface between cryptocrystalline graphite and natural rubber, and is beneficial to improving the mechanical properties and processing properties of sound insulation rubber; 3. In view of the problems of small particle size, many surface impurities and high surface activity of cryptocrystalline graphite, the present invention creatively prepares a sound insulation rubber material with good effect through two oxidation intercalation modification, blending and kneading of modified cryptocrystalline graphite with natural rubber and additives, and vulcanization. The material has clear mechanism, simple process, excellent product, broad application prospects and is suitable for industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, some of the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be made based on these drawings without paying any creative work.

[0027] Figure 1 is a process flow chart of Example 1 of the present invention; Figure 2 It is a sound insulation test chart of Examples 1-3 of the present invention and Comparative Examples 1-2. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, a specific implementation scheme is now described in detail.

[0029] The present invention is further described below in conjunction with the 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 the different requirements of specific use, and the implementation conditions not indicated are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0030] Example 1 See attached Figure 1 And attached Figure 2 This embodiment provides a method for preparing a modified cryptocrystalline graphite sound insulation rubber, comprising the following steps: (1) Solution I is prepared by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid in a mass ratio of 1:10, and cryptocrystalline graphite with a fixed carbon content of 83.32% is added to Solution I in a solid-liquid ratio of 1:4 and stirred for 90 minutes of pre-oxidation and intercalation treatment. After the pre-oxidation and intercalation reaction is completed, concentrated nitric acid of the same weight as the cryptocrystalline graphite is added for secondary oxidation and intercalation for 120 minutes. After the reaction is completed, the solid product I is collected; (2) ultrasonically washing the solid product I until the product is neutral, and collecting the solid product as solid product II; (3) In parts by weight, weigh 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 order and add them into an internal mixer. Set the temperature to 80°C and the internal mixing time to 10 minutes. After the internal mixing is completed, put the discharged rubber into a flat vulcanizer for vulcanization treatment. The vulcanization time is 13 minutes and the temperature is 140°C. After the vulcanization is completed, collect the solid product III; (4) The solid product III is aged at a constant temperature of 23°C for 24 hours to obtain a modified cryptocrystalline graphite sound insulation rubber.

[0031] Example 2 See attached Figure 2 This embodiment provides a method for preparing a modified cryptocrystalline graphite sound insulation rubber, comprising the following steps: (1) Solution I is prepared by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid in a mass ratio of 1:10, and cryptocrystalline graphite with a fixed carbon content of 83.32% is added to Solution I in a solid-liquid ratio of 1:4 and stirred for 90 minutes of pre-oxidation and intercalation treatment. After the pre-oxidation and intercalation reaction is completed, concentrated nitric acid of the same weight as the cryptocrystalline graphite is added for secondary oxidation and intercalation for 120 minutes. After the reaction is completed, the solid product I is collected; (2) ultrasonically washing the solid product I until the product is neutral, and collecting the solid product as solid product II; (3) In parts by weight, weigh 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 order and add them into an internal mixer. Set the temperature to 80°C and the internal mixing time to 10 minutes. After the internal mixing is completed, put the discharged rubber into a flat vulcanizer for vulcanization treatment. The vulcanization time is 13 minutes and the temperature is 140°C. After the vulcanization is completed, collect the solid product III; (4) The solid product III is aged at a constant temperature of 23°C for 24 hours to obtain a modified cryptocrystalline graphite sound insulation rubber.

[0032] Example 3 See attached Figure 2 This embodiment provides a method for preparing a modified cryptocrystalline graphite sound insulation rubber, comprising the following steps: (1) Solution I is prepared by mixing hydrogen peroxide (concentration of 30 wt.%) and concentrated sulfuric acid in a mass ratio of 1:10, and cryptocrystalline graphite with a fixed carbon content of 83.32% is added to Solution I in a solid-liquid ratio of 1:4 and stirred for 90 minutes of pre-oxidation and intercalation treatment. After the pre-oxidation and intercalation reaction is completed, concentrated nitric acid of the same weight as the cryptocrystalline graphite is added for secondary oxidation and intercalation for 120 minutes. After the reaction is completed, the solid product I is collected; (2) ultrasonically washing the solid product I until the product is neutral, and collecting the solid product as solid product II; (3) In parts by weight, weigh 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 order and add them into an internal mixer. Set the temperature to 80°C and the internal mixing time to 10 min. After the internal mixing is completed, put the discharged rubber into a flat vulcanizer for vulcanization treatment. The vulcanization time is 13 min and the temperature is 140°C. After the vulcanization is completed, collect the solid product III; (4) The solid product III is aged at a constant temperature of 23°C for 24 hours to obtain a modified cryptocrystalline graphite sound insulation rubber.

[0033] Comparative Example 1 See attached Figure 2 This comparative example is carried out on the basis of the above-mentioned embodiment 1, and the similarities with the above-mentioned embodiment 1 are not repeated here.

[0034] In this comparative example, modified cryptocrystalline graphite was not used but 30 parts of montmorillonite was used as the rubber filler, and the other conditions were the same as those in Example 1.

[0035] Comparative Example 2 See attached Figure 2 This comparative example is carried out on the basis of the above-mentioned embodiment 2, and the similarities with the above-mentioned embodiment 2 are not repeated here.

[0036] In this comparative example, modified cryptocrystalline graphite was not used but 40 parts of carbon black was used as the rubber filler, and the rest were the same as in Example 2.

[0037] The sound insulation rubbers prepared in Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2 were tested for tensile properties, tear strength, Shore hardness, effective sound insulation frequency band and sound insulation peak value. The test results are shown in Table 1. The sound insulation test graph is shown in Figure 2 shown.

[0038] Table 1

[0039] From Table 1, Comparative Example 1 does not use modified cryptocrystalline graphite as a filler but uses 30 parts of montmorillonite as a rubber filler. The mechanical properties of the sound insulation rubber are lower than those of Example 1, and the sound insulation is only higher than 10dB within 1004Hz-1600Hz; Comparative Example 2 does not use modified cryptocrystalline graphite but uses 40 parts of carbon black as a rubber filler, and its mechanical properties are not much different from those of Example 2, but the sound insulation is only higher than 10dB within 880Hz-1600Hz; By comparing Example 1, Example 2 and Example 3, the mechanical properties and sound insulation of Example 2 are the best, and the sound insulation is higher than 10dB within the sound wave frequency of 300Hz-1600Hz, that is, 90% sound wave isolation is achieved.

[0040] In summary, the present invention improves the surface properties of cryptocrystalline graphite through two oxidation intercalation modifications, enhances its dispersibility and flexibility, and is beneficial to its subsequent interface composite with rubber; the present invention effectively solves the problem of preferential orientation when cryptocrystalline graphite is composited with natural rubber by blending and kneading the cryptocrystalline graphite modified by two oxidation intercalation with natural rubber and additives, improves the stability of the interface between cryptocrystalline graphite and natural rubber, and is beneficial to improving the mechanical properties and processing properties of sound insulation rubber; in view of the problems of small particle size, many surface impurities, and high surface activity of cryptocrystalline graphite, the present invention creatively prepares a sound insulation rubber material with good effect through two oxidation intercalation modifications, blending and kneading of modified cryptocrystalline graphite with natural rubber and additives, and vulcanization, etc., with clear mechanism, simple process, excellent product, broad application prospect, and suitable for industrial promotion.

[0041] The preferred modification and preparation process conditions of the above embodiments are obtained based on a large number of exploratory experiments and scientific experimental designs of single variable and orthogonal experiments. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical scheme of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

[0042] The various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further explain various possible combinations.

[0043] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0044] In summary, the above description of the disclosed embodiments enables professionals and technicians in the field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing modified cryptocrystalline graphite sound insulation rubber, characterized in that: The following steps are involved: (1) Weigh cryptocrystalline graphite, add solution I, stir and perform pre-oxidation intercalation treatment, add a strong acid of the same weight as the cryptocrystalline graphite for secondary oxidation intercalation after the pre-oxidation intercalation reaction is completed, and collect the solid product I after the reaction is completed; (2) washing the solid product I until the product is neutral, and collecting the 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 order, add them to an internal mixer and control the temperature for internal mixing. After the internal mixing is completed, place the rubber material in a flat vulcanizer and control the temperature for vulcanization. After vulcanization, collect the solid product III; (4) The solid product III is aged at a constant temperature for 24 hours to obtain a modified cryptocrystalline graphite sound insulation rubber.

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

4. The method for preparing a modified cryptocrystalline graphite sound insulation rubber according to claim 1, characterized in that: In step (1), the strong acid added in 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 insulation rubber according to claim 1, characterized in that: In step (2), the solid product I is washed in a manner selected from the group consisting of water rinsing, ultrasonic washing, and centrifugal washing, and the washing endpoint is determined by whether the washing water is neutral.

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

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

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

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