A fluororubber material and preparation method thereof

Abstract

The present invention discloses a fluororubber material and a preparation method thereof, belonging to the technical field of rubber material preparation. The fluororubber material comprises, by weight, 100 parts of a fluororubber component, 1-5 parts of a vulcanizing agent, 5-10 parts of an acid scavenger, 10-30 parts of micron-sized spherical hollow powder, and 1-5 parts of a processing aid. The preparation method comprises the following steps: placing fluororubber raw rubber and micron-sized spherical hollow powder into an internal mixer for mixing; subsequently performing open mixing, and sequentially adding an acid scavenger, a processing aid, and a vulcanizing agent during the open mixing process; and finally vulcanizing the open mixing product to obtain the obtained product. By introducing a novel micron-sized spherical hollow powder material, the present invention significantly reduces the material cost of fluororubber without increasing the overall density of the material and without reducing the elongation at break at high temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of rubber material preparation, and in particular relates to a fluororubber material and a preparation method thereof. Background Art

[0002] Special fluororubber has the advantages of high temperature resistance above 200°C, oil resistance, medium resistance, weather resistance, insulation, and good physical and mechanical properties. It has very critical and extensive applications in oil fields, automobiles, aerospace and other fields.

[0003] In the current existing technology, the cost of fluororubber materials is relatively high, about 30,000 yuan / ton, and the overall density of pure fluororubber materials is 1.5-1.6g / cm 3 , with an elongation at break exceeding 240% at 200°C. To reduce material costs, large-particle carbon black fillers such as N990 are generally added to fluororubber during its preparation. However, this preparation method presents several challenges, including high material density and low elongation at break, especially at high temperatures. Durability needs to be further improved in high-temperature environments under certain strains. Summary of the Invention

[0004] The purpose of the present invention is to provide a fluororubber material and a preparation method thereof. By introducing a new micron-sized spherical hollow powder material, the material cost of the fluororubber is greatly reduced without increasing the overall density of the material or reducing the elongation at break at high temperature.

[0005] To achieve the above objectives, the present invention adopts the following specific technical solutions:

[0006] A fluororubber material comprises, by weight, 100 parts of a fluororubber component, 1-5 parts of a vulcanizing agent, 5-10 parts of an acid absorber, 10-30 parts of micron-sized spherical hollow powders and 1-5 parts of a processing aid.

[0007] Furthermore, the micron-sized spherical hollow powder includes a hollow powder having a plurality of closed small cavities inside and / or a hollow powder having a single large cavity inside.

[0008] The present invention also provides a method for preparing the fluororubber material, comprising the following steps:

[0009] S1: Put the fluororubber raw rubber and micron-sized spherical hollow powder into an internal mixer for mixing.

[0010] Furthermore, the mixing temperature is 100-200° C., and the mixing time is 3-10 minutes.

[0011] S2: placing the product obtained in step S1 on an open mill for open refining, and sequentially adding an acid absorbent, a processing aid, and a vulcanizing agent during the open refining process.

[0012] Furthermore, the temperature of the open refining is 50-100° C., and the time of the open refining is 5-10 minutes.

[0013] Preferably, the acid absorber is one or more of MgO, CaO, Ca(OH)2, ZnO, PbO or dibasic lead phosphite.

[0014] Preferably, the processing aid is one or more of fluorowax, low molecular weight polyethylene, zinc stearate, Ws 280, palm wax or Modelli 935.

[0015] Preferably, the vulcanizing agent is one or more of hydroquinone, bisphenol A or bisphenol AF.

[0016] S3: placing the product obtained in step S2 into a vulcanizing machine for vulcanization to obtain the product.

[0017] Furthermore, the vulcanization is as follows: firstly, a first stage vulcanization is performed at a temperature of 165-170° C. for 5-15 minutes; and then the temperature is gradually increased to perform a second stage vulcanization at a temperature of 220-240° C. for 18-24 hours.

[0018] In a preferred technical solution, the micron-sized spherical hollow powder added in step S1 is a spherical hollow powder having multiple closed small cavities inside, which can form a strong link with the fluororubber molecular chain by utilizing its surface open pore structure, thereby maintaining the elongation at break of the fluororubber at high temperature. In step S2, the spherical hollow powder having a single large cavity inside is added before the acid absorber is added, which can further ensure the elongation at break of the fluororubber material at high temperature while preventing a significant decrease in the overall density of the fluororubber material.

[0019] The spherical hollow powder with multiple closed small cavities inside has a bulk density of 0.5-0.8g / cm 3 The overall porosity is 20-50%. The particle size is 5-50μm, the surface pore size is 2-5μm, the average diameter of the small cavity is 3-10μm, and the average wall thickness of the small cavity is 2-5μm.

[0020] The preparation method of the spherical hollow powder having multiple closed small cavities inside is as follows:

[0021] (1) 40-50% silicon dioxide, 40-50% aluminum oxide, 5-10% calcium oxide and water are prepared into a slurry, and the powder is ground to a particle size of 1 μm-5 μm; (2) the product of step (1) is divided into two parts, slurry A and slurry B, a first binder and a first surfactant are added to the slurry A, and the mixture is stirred evenly to obtain a foam slurry C with a diameter of 5-50 μm; a second binder and a second surfactant are added to the slurry B, and the mixture is stirred evenly to obtain a foam slurry D with a diameter of 1-10 μm; the foam slurries C and D are mixed and stirred evenly; (3) the product obtained in step (2) is atomized and formed in a molding tower to obtain a spherical hollow powder blank; (4) the spherical hollow powder blank obtained in step (3) is sintered and cooled to obtain the final product.

[0022] The spherical hollow powder with a single large cavity inside has a bulk density of 0.5-0.8 g / cm 3 The overall porosity is 10-80%, the particle size is 5-50μm, and the surface pore size is 2-5μm.

[0023] The preparation method of the spherical hollow powder having a single large cavity inside is as follows:

[0024] (1) 40-50% silicon dioxide, 40-50% aluminum oxide, 5-10% calcium oxide and water are mixed into a slurry, and the powder particle size is ground to a powder particle size of 0.5 μm-2 μm; (2) a binder and a surfactant are added to the ground slurry, and the mixture is stirred to form a foam slurry; (3) the foam slurry is transported to a closed reactor for aging reaction and stirred evenly. (4) the obtained product is atomized and formed in a forming tower to obtain a spherical hollow powder body. (5) the spherical hollow powder body obtained in step (4) is sintered and cooled to obtain the obtained product.

[0025] Compared with the existing technology, the present invention introduces a new type of micron-sized spherical hollow powder material with low manufacturing cost. Due to its unique hollow structure, it has excellent properties such as low density and large specific surface area, and does not increase the overall density of the material. At the same time, through the surface open pore structure, it forms a strong link with the fluororubber molecular chain, maintaining the tensile elongation of the fluororubber at high temperature, thereby maintaining the durability of the fluororubber in high temperature environment. DETAILED DESCRIPTION

[0026] The embodiments of the present invention will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] Example 1

[0028] A method for preparing the fluororubber material comprises the following steps:

[0029] S1: 100 g of fluororubber raw rubber and 20 g of micron-sized spherical hollow powder were placed in an internal mixer and mixed at 150° C. for 5 min.

[0030] The micron-sized spherical hollow powder has multiple closed small cavities inside, and its bulk density is 0.56 g / cm 3 The overall porosity is 22%, the particle size is 19 μm, the surface pore size is 2 μm, the average diameter of the small cavities is 3 μm, and the average wall thickness of the small cavities is 2 μm. The preparation method is as follows: (1) SiO2 powder, Al2O3 powder, and CaO powder in a mass ratio of 50:40:10 are mixed evenly and prepared with water to form a slurry; the mass fraction of the powder raw materials is about 40%, and the mass fraction of water is about 60%. The slurry is ground to a powder particle size between 3 μm and 10 μm. (2) The product of step (1) is divided into two parts, slurry A and slurry B, according to a mass ratio of 1:8. 2.5% water glass and 1% animal protein are added to the slurry A, and the mixture is stirred to form a foam slurry C with a foam diameter of 0.05-0.3 mm. 1% water glass and 0.3% SDS are added to the slurry B, and the mixture is stirred to form a foam slurry D with a foam diameter of 5-50 μm. The foam slurries C and D are then mixed and stirred evenly. (3) The product obtained in (2) is transported into a forming tower using a diaphragm pump. The inlet temperature of the forming tower is 300° C., and the outlet temperature of the forming tower is 150° C., and the spherical hollow powder body is obtained by atomization molding. (4) The spherical hollow powder body obtained in step (3) is placed in a sagger and sintered in a muffle furnace at a sintering temperature of 1100° C. for a holding time of 0.5 h. The spherical hollow powder body having a plurality of closed small cavities inside is obtained after cooling to room temperature.

[0031] S2: The mixed micelles were placed on an open mill, and 5 g of MgO, 3 g of fluorowax and 3 g of bisphenol A were added in sequence, and the mixture was milled at 70° C. for 10 min.

[0032] S3: The material obtained by the open mill is placed in a vulcanizer and first vulcanized at a temperature of 165°C for 15 minutes; then the temperature is gradually increased to perform a second vulcanization at a temperature of 230°C for 24 hours to obtain the fluororubber material. After testing, the overall density of the fluororubber material is 1.78g / cm 3 , the elongation at break at 200℃ is 240%.

[0033] Example 2

[0034] A method for preparing the fluororubber material comprises the following steps:

[0035] (1) 100 g of fluororubber raw rubber and 30 g of micron-sized spherical hollow powder were placed in an internal mixer and mixed at 160° C. for 3 min. The spherical hollow powder was the same as that in Example 1.

[0036] (2) The mixed micelles were placed on an open mill, and 3 g of Ca(OH)2, 1 g of zinc stearate, and 1 g of hydroquinone were added in sequence, and the mixture was milled at 80°C for 5 min.

[0037] (3) The material obtained by the open refining is placed in a vulcanizer and first vulcanized at a temperature of 170°C for 10 minutes; then the temperature is gradually increased to perform a second vulcanization at a temperature of 230°C for 20 hours to obtain the fluororubber material. After testing, the overall density of the fluororubber material is 1.73g / cm 3 , the elongation at break at 200℃ is 220%.

[0038] Example 3

[0039] A method for preparing the fluororubber material comprises the following steps:

[0040] (1) 100 g of fluororubber raw rubber and 10 g of micron-sized spherical hollow powder were placed in an internal mixer and mixed at 100° C. for 10 min. The spherical hollow powder was the same as that in Example 1.

[0041] (2) The mixed micelle was placed on an open mill, and 3 g of ZnO, 3 g of palm wax, and 3 g of bisphenol AF were added in sequence, and the mixture was milled at 100° C. for 5 min.

[0042] (3) The material obtained by the open refining is placed in a vulcanizer and first vulcanized at a temperature of 170°C for 5 minutes; then the temperature is gradually increased to perform a second vulcanization at a temperature of 220°C for 24 hours to obtain the fluororubber material. After testing, the overall density of the fluororubber material is 1.82g / cm 3 , the elongation at break at 200℃ is 260%.

[0043] Example 4

[0044] A method for preparing the fluororubber material is different from that of Example 1 in that: in step S2, a spherical hollow powder having a single large cavity inside is added before adding MgO, and the bulk density thereof is 0.59 g / cm 3 , the overall porosity is 75%, the particle size is 38μm, and the surface pore size is 4μm.

[0045] The preparation method of the spherical hollow powder with a single large cavity inside is as follows: (1) SiO2 powder, Al2O3 powder and CaO powder with a mass ratio of 40:40:20 are mixed evenly and prepared into a slurry with water; the mass fraction of the powder raw materials is about 40%, the mass fraction of water is about 60%, and the powder is ground to a particle size between 0.5μm and 2μm. (2) 4% water glass and 0.8% SDS are added to the ground slurry, and the mixture is stirred to form a foam slurry with an average diameter of 0.05mm. (3) The foam slurry is transported to a closed reactor and subjected to an aging reaction at 25°C for 12 hours. The reaction is carried out under stirring and the mixture is stirred evenly. (4) The product obtained in step (3) is transported into a forming tower by a diaphragm pump, the inlet temperature of the forming tower is 300°C, and the outlet temperature of the forming tower is 150°C, and the spherical hollow powder body is obtained by atomization molding. (5) The spherical hollow powder body obtained in step (4) is placed in a sagger and sintered in a muffle furnace at a sintering temperature of 1400° C. for a holding time of 0.5 h. The spherical hollow powder body is cooled to room temperature to obtain the spherical hollow powder body having a single large cavity inside.

[0046] After testing, the overall density of the fluororubber material prepared in this embodiment is 1.69g / cm 3 , the elongation at break at 200℃ is 245%.

[0047] Example 5

[0048] A method for preparing the fluororubber material is different from that of Example 2 in that: in step S2, the spherical hollow powder having a single large cavity inside as described in Example 4 is added before adding Ca(OH)2.

[0049] After testing, the overall density of the fluororubber material prepared in this embodiment is 1.65g / cm 3 , the elongation at break at 200℃ is 230%.

[0050] Comparative Example 1

[0051] A method for preparing the fluororubber material, compared with Example 1, is as follows: in step S1, instead of adding the 20 g micron-sized spherical hollow powder, 30 g N990 carbon black is added. The remaining steps are the same as in Example 1.

[0052] After testing, the overall density of the fluororubber material prepared in this comparative example is 1.85 g / cm 3 , the elongation at break at 200℃ is 180%.

[0053] The fluororubber materials prepared in Examples 1-5 can significantly reduce material costs to several thousand yuan per ton due to the successful introduction of new, low-cost micron-sized spherical hollow powders. The overall density of the fluororubber materials in Examples 1 and 3 is relatively increased, but the elongation at break at high temperatures is relatively high. The fluororubber materials prepared in Examples 4-5 are even better, with an overall density that can be controlled at 1.70 g / cm 3 Below, at the same time, the elongation at break has basically not decreased compared with pure fluororubber material.

[0054] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will appreciate that the technical solutions described in the aforementioned embodiments may be modified, or some or all of the technical features therein may be replaced with equivalents. Such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the various embodiments of the present invention. Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, the combination of features from different embodiments is intended to be within the scope of the present invention and to form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background technology of the present invention and should not be construed as an admission or any form of implication that such information constitutes prior art already known to those skilled in the art.

Claims

1. A fluororubber material, characterized in that: In parts by weight, it comprises 100 parts of fluororubber component, 1-5 parts of vulcanizing agent, 5-10 parts of acid absorbent, 10-30 parts of micron-sized spherical hollow powder and 1-5 parts of processing aid; The micron-sized spherical hollow powder is a hollow powder having multiple closed small cavities inside; or a hollow powder having multiple closed small cavities inside and a hollow powder having a single large cavity inside; The acid absorber is one or more of MgO, CaO, Ca(OH)2, ZnO, PbO or dibasic lead phosphite; the processing aid is one or more of fluorowax, low molecular weight polyethylene, zinc stearate, Ws 280, and palm wax; the vulcanizing agent is one or more of hydroquinone, bisphenol A or bisphenol AF; The spherical hollow powder with multiple closed small cavities inside has a bulk density of 0.5-0.8g / cm 3 The overall porosity is 20-50%; the particle size is 5-50μm, the surface pore size is 2-5μm, the average diameter of the small cavity is 3-10μm, and the average wall thickness of the small cavity is 2-5μm; The preparation method of the spherical hollow powder having multiple closed small cavities inside is as follows: (1) 40-50% silicon dioxide, 40-50% aluminum oxide, 5-10% calcium oxide and water are prepared into a slurry, and the powder is ground to a particle size of 1 μm-5 μm; (2) the product in step (1) is divided into two parts, slurry A and slurry B, a first binder and a first surfactant are added to the slurry A, and the mixture is stirred evenly to obtain a foam slurry C with a diameter of 5-50 μm; a second binder and a second surfactant are added to the slurry B, and the mixture is stirred evenly to obtain a foam slurry D with a diameter of 1-10 μm; the foam slurry C and the foam slurry D are mixed and stirred evenly; (3) the product obtained in step (2) is atomized and formed in a molding tower to obtain a spherical hollow powder body; (4) the spherical hollow powder body obtained in step (3) is sintered and cooled to obtain the obtained product; The spherical hollow powder with a single large cavity inside has a bulk density of 0.5-0.8 g / cm 3 , the overall porosity is 10-80%, the particle size is 5-50μm, and the surface pore size is 2-5μm; The preparation method of the spherical hollow powder having a single large cavity inside is as follows: (1) 40-50% silicon dioxide, 40-50% aluminum oxide, 5-10% calcium oxide and water are prepared into a slurry, and the mixture is ground to a powder particle size of 0.5 μm-2 μm; (2) a binder and a surfactant are added to the ground slurry, and the mixture is stirred to form a foam slurry; (3) the foam slurry is transported to a closed reactor, subjected to an aging reaction, and stirred uniformly; (4) the obtained product is atomized and formed in a forming tower to obtain a spherical hollow powder body; (5) the spherical hollow powder body obtained in step (4) is sintered, and the obtained spherical hollow powder body is obtained after cooling.

2. A method for preparing the fluororubber material according to claim 1, characterized in that: The steps include: S1: Put fluororubber raw rubber and micron-sized spherical hollow powder into an internal mixer for mixing; S2: placing the product obtained in step S1 on an open mill for open refining, and sequentially adding an acid absorbent, a processing aid, and a vulcanizing agent during the open refining process; S3: Sulfurizing the product obtained in step S2 to obtain; The micron-sized spherical hollow powder added in step S1 is a hollow powder having multiple closed small cavities inside; In step S2, the hollow powder having a single large cavity inside is added before the acid scavenger is added.

3. The method for preparing a fluororubber material according to claim 2, wherein: In step S1, the mixing temperature is 100-200° C., and the mixing time is 3-10 minutes.

4. The method for preparing a fluororubber material according to claim 2, wherein: In step S2, the temperature of the open refining is 50-100°C, and the time of the open refining is 5-10 minutes.

5. The method for preparing a fluororubber material according to claim 2, characterized in that: In step S3, the vulcanization is as follows: firstly, a first stage vulcanization is performed at a temperature of 165-170° C. for 5-15 minutes; then, the temperature is gradually increased to perform a second stage vulcanization at a temperature of 220-240° C. for 18-24 hours.