Production process of single-stage gas holder rubber sealing membrane

Abstract

The present invention discloses a single-stage gasholder rubber sealing film production process, which belongs to the technical field of rubber sealing films and comprises the following steps: first, adding tartaric acid modified graphene oxide and γ-mercaptopropyltrimethoxysilane to a polytetrafluoroethylene sealed can, loading the mixture into a reactor, and maintaining the mixture at 180°C for 6 hours to obtain modified graphene oxide; second, plasticizing acrylonitrile-butadiene rubber and fluororubber respectively, then uniformly mixing the two plasticized rubbers, sequentially adding modified silica, activated magnesium oxide, calcium hydroxide, modified graphene oxide, and carnauba wax, and finally adding a vulcanizing agent and an accelerator, thinning the mixture 10 times, and then forming a triangular package and removing the film; one-stage vulcanization is carried out on a common hydraulic flat vulcanizing press to obtain a single-stage gasholder rubber sealing film. In the present invention, the use of rubber as a matrix rubber material can reduce costs, combine the use of modified silica and modified graphene, and also do not reduce product performance.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber sealing films, and in particular relates to a production process of a single-stage gas cabinet rubber sealing film. Background Art

[0002] A gasholder is a common container used to store raw, semi-finished, or finished gases in production facilities. Sealing is paramount for a gasholder, specifically preventing leakage between the fixed outer cylinder and the movable piston. Managing the sealing mechanism and sealing medium is crucial, particularly protecting the rubber sealing membrane.

[0003] Existing rubber sealing membranes are made of general-purpose rubber or a rubber-plastic blend, which has average corrosion resistance and is primarily used to store non-corrosive, low-corrosive, or low-corrosive gaseous media. For example, coke oven gas contains significant amounts of corrosive components such as benzene, naphthalene, anthracene, sulfur dioxide, hydrogen sulfide, ammonia, and unsaturated hydrocarbons. These components condense in the gasholder as liquid coal tar, which can be highly corrosive to rubber sealing membranes. When used with highly corrosive gases or those containing a high proportion of corrosive components, rubber sealing membranes generally have a short service life of less than three years, requiring frequent repair and replacement of components. Furthermore, they present a potential safety hazard of gas leakage. Summary of the Invention

[0004] The object of the present invention is to provide a single-stage gas cabinet rubber sealing membrane production process to solve the problems in the background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The production process of a single-stage gas holder rubber sealing membrane includes the following steps:

[0007] The first step is to add tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane into a polytetrafluoroethylene sealed can, put it into a reactor, and maintain it at 180°C for 6 hours to obtain modified graphene oxide; in the synthesis process of modified graphene, tartaric acid-modified graphene oxide is used as the core, and two competing reactions occur on the tartaric acid-modified graphene oxide. The active functional group in γ-mercaptopropyltrimethoxysilane reacts with the carboxyl group on the tartaric acid-modified graphene oxide and is grafted onto its surface. At the same time, the -OCH3 in γ-mercaptopropyltrimethoxysilane is hydrolyzed and the hydroxyl group is condensed to synthesize modified graphene oxide with tartaric acid-modified graphene oxide as the core and coated with a silane coupling agent.

[0008] The second step is to weigh the raw materials according to parts by weight, and respectively plasticize the acrylonitrile-butadiene rubber and fluororubber, then mix the two plasticized rubbers, add modified white carbon black, activated magnesium oxide, calcium hydroxide, modified graphene oxide, and Brazilian palm wax in sequence, and finally add vulcanizing agent and accelerator. After 10 passes, make a triangle bag and put it into the next sheet; one-stage vulcanization is carried out on a common hydraulic flat vulcanizing press to obtain a single-stage gas cabinet rubber sealing membrane. The consideration of compatibility is crucial in the rubber blending process. When the compatibility is poor, the interfacial adhesion between the two components is weak, which will cause the blended rubber to separate in use. In the present invention, by adjusting the ratio of fluororubber and acrylonitrile-butadiene rubber, while coordinating the use of modified white carbon black and modified graphene, the performance of the material can be better utilized.

[0009] As a further improvement of the present invention, the usage ratio of tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane is 0.2 g:10 mL.

[0010] As a further improvement of the present invention, the vulcanization conditions are temperature 175° C., pressure 15 MPa, and time 15 min; and the second-stage vulcanization is carried out in an oven under the conditions of temperature 145° C., pressure 10 MPa, and time 5 h.

[0011] As a further improvement of the present invention, the tartaric acid-modified graphene oxide is prepared by the following steps:

[0012] Graphene oxide and N,N-dimethylformamide were mixed and ultrasonically dispersed for 2 hours to obtain a suspension, and then tartaric acid was added and ultrasonically dispersed for 2 hours. The temperature was then set to 60°C and oscillated at a constant temperature for 4 hours. The temperature was then raised to 80°C and oscillated for another 2 hours. After the reaction was completed, the mixture was washed with water until neutral, and then vacuum dried at -60°C for 24 hours to obtain tartaric acid-modified graphene oxide.

[0013] As a further improvement of the present invention, the concentration of tartaric acid is 2 mol / L; the usage ratio of graphene oxide, N,N-dimethylformamide and tartaric acid is 0.1 g:50 mL:5 mL.

[0014] As a further improvement of the present invention, modified silica is prepared by the following steps:

[0015] Step 1: Under nitrogen protection, 3,5-di-tert-butyl salicylaldehyde is dissolved in anhydrous ethanol, and then an aminosilane coupling agent is added, and the mixture is heated under reflux for 6 hours to obtain a treatment solution; the molar ratio of 3,5-di-tert-butyl salicylaldehyde to the aminosilane coupling agent is 1:1;

[0016] Step 2: Mix the treatment liquid and a 90% ethanol aqueous solution in a volume ratio of 1:4, spray the mixture onto the surface of the silica, stir and mix for 10 minutes, vacuum dry at 120°C for 6 hours, wash with anhydrous ethanol, and finally vacuum dry at 50°C to constant weight to obtain modified silica. The ratio of treatment liquid to silica is 5 mL:2 g. In the present invention, 3,5-di-tert-butyl salicylaldehyde is selected as a raw material. It can be used as a hindered phenol antioxidant component, which is more environmentally friendly, non-toxic, and less polluting. Compared with hindered amine antioxidants, it has similar environmental performance. It also addresses the disadvantage that antioxidant components are not resistant to migration and are easily extracted by oil and lose their effectiveness.

[0017] As a further improvement of the present invention, the aminosilane coupling agent is one of γ-aminopropyltriethoxysilane and γ-aminoethylaminopropyltrimethoxysilane.

[0018] As a further improvement of the present invention, in parts by weight, 20-25 parts of nitrile rubber, 75-80 parts of fluororubber, 30-32 parts of modified silica, 13.2-13.4 parts of active magnesium oxide, 4-4.2 parts of calcium hydroxide, 3.8-4 parts of modified graphene oxide, 1-1.2 parts of carnauba wax, 3-3.5 parts of vulcanizing agent and 1.5-1.8 parts of accelerator.

[0019] Beneficial effects of the present invention:

[0020] In the present invention, rubber is selected and used as the base rubber material, and fluororubber and nitrile rubber are selected as the rubber. The electronegativity of the fluorine atom in the fluororubber is extremely high, which makes the C-F bond energy larger, while promoting the improvement of the C-C main chain bond energy, and forming a hydrogen bond between F and H by using a strong van der Waals force, which has the most excellent medium resistance and acid and alkali resistance. At the same time, the ratio of nitrile rubber can reduce costs without reducing product performance.

[0021] By grafting hindered phenol groups with anti-aging properties onto the surface of silica, the present invention addresses the problem of migration and volatilization of traditional small-molecule antioxidants, without compromising anti-aging effectiveness or causing environmental pollution. Immobilizing the antioxidant on a carrier to prepare a supported antioxidant reduces its mobility. Furthermore, silica, as a filler, is prone to agglomeration, so treatment with a treatment solution further enhances its dispersion within the rubber matrix.

[0022] The present invention also prepares a modified graphene. Since graphene has excellent wear resistance and corrosion resistance and is chemically inert, its application in a rubber sealing film can improve the mechanical properties of the material. At the same time, the surface of the modified graphene undergoes chemical cross-linking under the action of a vulcanizing agent, which can enhance the interaction between the graphene and the polymer matrix and improve the dispersibility of the graphene in the polymer matrix. At the same time, compared with materials without modified graphene, materials with modified graphene added have better resistance to gas permeation, which is more conducive to improving the gas corrosion resistance of the rubber sealing film. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] Example 1

[0025] This embodiment provides a modified silica, which is prepared by the following steps:

[0026] Step 1: Under nitrogen protection, 3,5-di-tert-butyl salicylaldehyde is dissolved in anhydrous ethanol, and then γ-aminopropyltriethoxysilane is added, and the mixture is heated under reflux for 6 hours to obtain a treatment solution; the molar ratio of 3,5-di-tert-butyl salicylaldehyde to γ-aminopropyltriethoxysilane is 1:1;

[0027] Step 2: Mix the treatment liquid and a 90% ethanol aqueous solution in a volume ratio of 1:4, then spray it on the surface of silica, stir and mix for 10 minutes, vacuum dry it at 120°C for 6 hours, then wash it with anhydrous ethanol, and finally vacuum dry it at 50°C to constant weight to obtain modified silica; the usage ratio of the treatment liquid and silica is 5mL:2g.

[0028] Example 2

[0029] This embodiment provides a modified silica, which is prepared by the following steps:

[0030] Step 1. Under nitrogen protection, 3,5-di-tert-butyl salicylaldehyde is dissolved in anhydrous ethanol, and then γ-aminoethylaminopropyltrimethoxysilane is added, and the mixture is heated under reflux for 6 hours. After the reaction is completed, a treatment liquid is obtained; the molar ratio of 3,5-di-tert-butyl salicylaldehyde and γ-aminoethylaminopropyltrimethoxysilane is 1:1; the amount ratio of 3,5-di-tert-butyl salicylaldehyde and anhydrous ethanol is 1g:10mL;

[0031] Step 2: Mix the treatment liquid and a 90% ethanol aqueous solution in a volume ratio of 1:4, then spray it on the surface of silica, stir and mix for 10 minutes, vacuum dry it at 120°C for 6 hours, then wash it with anhydrous ethanol, and finally vacuum dry it at 50°C to constant weight to obtain modified silica; the usage ratio of the treatment liquid and silica is 5mL:2g.

[0032] Example 3

[0033] This embodiment provides a tartaric acid-modified graphene oxide, which is prepared by the following steps:

[0034] Graphene oxide and N,N-dimethylformamide were mixed and ultrasonically dispersed for 2 hours to obtain a suspension, and then 2 mol / L tartaric acid was added and ultrasonically dispersed for 2 hours. The temperature was then set to 60°C and oscillated at a constant temperature for 4 hours. The temperature was then raised to 80°C and oscillated for another 2 hours. After the reaction was completed, the mixture was washed with water until neutral, and then vacuum dried at -60°C for 24 hours to obtain tartaric acid-modified graphene oxide. The dosage ratio of graphene oxide, N,N-dimethylformamide and tartaric acid was 0.1 g:50 mL:5 mL.

[0035] Example 4

[0036] This embodiment provides a single-stage gas cabinet rubber sealing membrane production process, including the following steps:

[0037] The first step is to add the tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane prepared in Example 3 into a polytetrafluoroethylene sealed can, put it into a reactor, and maintain it at 180°C for 6 hours to obtain modified graphene oxide; the amount ratio of tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane is 0.2g:10mL.

[0038] The second step is to weigh the raw materials according to weight, and respectively plasticize 20 parts of nitrile rubber and 80 parts of fluororubber, and then mix the two plasticized rubbers evenly, and sequentially add 30 parts of modified white carbon black prepared in Example 1, 13.2 parts of active magnesium oxide, 4 parts of calcium hydroxide, 3.8 parts of modified graphene oxide, and 1 part of carnauba wax, and finally add 3 parts of vulcanizing agent DCP and 1.5 parts of accelerator TAIC. After thinning 10 times, make triangular packages and remove the sheets; the first stage vulcanization is carried out on an ordinary hydraulic flat vulcanizer under the conditions of temperature 175°C, pressure 15MPa, and time 15min; the second stage vulcanization is carried out in an oven under the conditions of temperature 145°C, pressure 10MPa, and time 5h to obtain a single-stage gas cabinet rubber sealing membrane, fluororubber, FPM-246G; nitrile rubber, NBR-40.

[0039] Example 5

[0040] This embodiment provides a single-stage gas cabinet rubber sealing membrane production process, including the following steps:

[0041] The first step is to add the tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane prepared in Example 3 into a polytetrafluoroethylene sealed can, put it into a reactor, and maintain it at 180°C for 6 hours to obtain modified graphene oxide; the amount ratio of tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane is 0.2g:10mL.

[0042] The second step is to weigh the raw materials according to weight, and respectively plasticize 25 parts of nitrile rubber and 75 parts of fluororubber, and then mix the two plasticized rubbers evenly, and sequentially add 32 parts of modified white carbon black prepared in Example 2, 13.2 parts of active magnesium oxide, 4 parts of calcium hydroxide, 3.8 parts of modified graphene oxide, and 1 part of carnauba wax, and finally add 3 parts of vulcanizing agent DCP and 1.5 parts of accelerator TAIC. After thinning 10 times, make triangular packages and remove the sheets; the first stage vulcanization is carried out on an ordinary hydraulic flat vulcanizer under the conditions of temperature 175°C, pressure 15MPa, and time 15min; the second stage vulcanization is carried out in an oven under the conditions of temperature 145°C, pressure 10MPa, and time 5h to obtain a single-stage gas cabinet rubber sealing membrane; fluororubber, FPM-246G; nitrile rubber, NBR-40.

[0043] Example 6

[0044] This embodiment provides a single-stage gas cabinet rubber sealing membrane production process, including the following steps:

[0045] The first step is to add the tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane prepared in Example 3 into a polytetrafluoroethylene sealed can, put it into a reactor, and maintain it at 180°C for 6 hours to obtain modified graphene oxide; the amount ratio of tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane is 0.2g:10mL.

[0046] The second step is to weigh the raw materials according to weight, and plasticize 25 parts of nitrile rubber and 75 parts of fluororubber respectively, then mix the two plasticized rubbers evenly, and add 32 parts of modified white carbon black prepared in Example 1, 13.4 parts of active magnesium oxide, 4.2 parts of calcium hydroxide, 4 parts of modified graphene oxide, and 1.2 parts of carnauba wax in sequence, and finally add 3.5 parts of vulcanizing agent DCP and 1.8 parts of accelerator TAIC. After thinning 10 times, make triangular packages and remove the sheets; the first stage vulcanization is carried out on an ordinary hydraulic flat vulcanizer under the conditions of temperature 175°C, pressure 15MPa, and time 15min; the second stage vulcanization is carried out in an oven under the conditions of temperature 145°C, pressure 10MPa, and time 5h to obtain a single-stage gas cabinet rubber sealing membrane, fluororubber, FPM-246G; nitrile rubber, NBR-40.

[0047] Comparative Example 1

[0048] In this comparative example, the modified silica in Example 6 was replaced by silica and an antioxidant, and the mass ratio of silica to antioxidant was 10:1.

[0049] Comparative Example 2

[0050] Compared with Comparative Example 1, this comparative example is characterized in that the modified graphene oxide is replaced with untreated graphene oxide, and the remaining raw materials and preparation process remain the same as those of Comparative Example 1.

[0051] Performance tests were performed on Examples 4 to 6 and Comparative Examples 1 to 2. The tensile strength and elongation at break were tested according to GB / T528-1998; the oil resistance was tested according to GB / T1690-1992, a test method for liquid resistance of vulcanized rubber. The results are shown in Table 1.

[0052] Table 1

[0053]

[0054] As can be seen from Table 1, Examples 4 to 6 are all superior to Comparative Examples 1 to 2 in performance. The untreated silica is less dispersible than the treated one and is prone to form aggregates, which will affect the overall performance of the material. The treated graphene oxide has better dispersibility between rubber materials, can form better interface interactions with the materials, and exhibits better resistance to gas permeation. In summary, the sealing film prepared by a single-stage gasholder rubber sealing film production process provided by the present invention has good mechanical properties and exhibits excellent gas permeation resistance.

[0055] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Single-stage gas cabinet rubber sealing membrane production process, characterized in that: The steps include: The first step is to mix graphene oxide and N,N-dimethylformamide and ultrasonically disperse them for 2 hours to obtain a suspension, then add tartaric acid and ultrasonically disperse them for 2 hours, then set the temperature to 60°C, and oscillate at a constant temperature for 4 hours, then raise the temperature to 80°C and continue to oscillate for 2 hours. After the reaction is completed, it is washed with water to neutrality and then vacuum-dried at -60°C for 24 hours to obtain tartaric acid-modified graphene oxide; after adding tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane to a polytetrafluoroethylene sealed can, the mixture is placed in a reactor and maintained at 180°C for 6 hours to obtain modified graphene oxide; The second step is to weigh the raw materials according to weight, plasticize the nitrile rubber and fluororubber separately, then mix the two plasticized rubbers evenly, add modified white carbon black, activated magnesium oxide, calcium hydroxide, modified graphene oxide, and carnauba wax in sequence, and finally add the vulcanizing agent and accelerator. After thinning 10 times, make a triangle bag and take off the sheet; the first stage vulcanization is carried out on a common hydraulic flat vulcanizer to obtain a single-stage gas cabinet rubber sealing membrane; In parts by weight, 20-25 parts of nitrile rubber, 75-80 parts of fluororubber, 30-32 parts of modified silica, 13.2-13.4 parts of activated magnesium oxide, 4-4.2 parts of calcium hydroxide, 3.8-4 parts of modified graphene oxide, 1-1.2 parts of carnauba wax, 3-3.5 parts of vulcanizing agent and 1.5-1.8 parts of accelerator; Modified silica is prepared by the following steps: Step 1: Under nitrogen protection, 3,5-di-tert-butyl salicylaldehyde is dissolved in anhydrous ethanol, and then an aminosilane coupling agent is added, and the mixture is heated under reflux for 6 hours to obtain a treatment solution; the molar ratio of 3,5-di-tert-butyl salicylaldehyde to the aminosilane coupling agent is 1:1; Step 2: Mix the treatment liquid and a 90% ethanol aqueous solution in a volume ratio of 1:4, then spray it on the surface of silica, stir and mix for 10 minutes, vacuum dry it at 120°C for 6 hours, then wash it with anhydrous ethanol, and finally vacuum dry it at 50°C to constant weight to obtain modified silica; the usage ratio of the treatment liquid and silica is 5mL:2g.

2. The single-stage gas cabinet rubber sealing membrane production process according to claim 1 is characterized in that: The usage ratio of tartaric acid-modified graphene oxide and γ-mercaptopropyltrimethoxysilane is 0.2 g:10 mL.

3. The single-stage gas cabinet rubber sealing membrane production process according to claim 1 is characterized in that: The vulcanization conditions are temperature 175°C, pressure 15 MPa, and time 15 minutes; the second-stage vulcanization is carried out in an oven under the conditions of temperature 145°C, pressure 10 MPa, and time 5 hours.

4. The single-stage gas cabinet rubber sealing membrane production process according to claim 1 is characterized in that: The concentration of tartaric acid is 2 mol / L; the usage ratio of graphene oxide, N,N-dimethylformamide and tartaric acid is 0.1 g:50 mL:5 mL.

5. The single-stage gas cabinet rubber sealing membrane production process according to claim 1 is characterized in that: The aminosilane coupling agent is one of γ-aminopropyltriethoxysilane and γ-aminoethylaminopropyltrimethoxysilane.

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