A fluorine rubber composite material with high wear resistance, high tear resistance and low compression permanent deformation and a preparation method thereof

Abstract

The application discloses a kind of high wear resistance, high tear, low compression permanent deformation fluorine rubber composite material and preparation method thereof, the fluorine rubber composite material is made of the following raw materials: fluorine rubber raw rubber: 100phr, reinforcing filler: 20~40phr, wear resistance modification component: 5~25phr, tear strength promotion component: 3~15phr, compression permanent deformation improvement component: 1~10phr, crosslinking system: 10~15phr, processing aid: 1~2phr.The application adds modified wear component, tear strength promotion component and compression permanent deformation improvement component, solves the problem that traditional material high tear strength and low compression permanent deformation are difficult to consider, is suitable for the high-speed rotating shaft rubber skin bowl, sealing ring and other movable seals in harsh environment such as gas turbine, has broad industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, and relates to a high-performance composite material based on fluororubber and its preparation method. Background Technology

[0002] Fluororubber, due to its excellent high-temperature resistance, chemical corrosion resistance, and aging resistance, has become an irreplaceable high-performance elastomer material in aerospace, automotive, and petrochemical industries. In practical applications, dynamic sealing and transmission components simultaneously face the combined effects of frictional wear, tearing stress, and continuous compression. Traditional fluororubber still has significant shortcomings in achieving a balance between high wear resistance, high tear resistance, and low compression set.

[0003] In existing technologies, research on the modification of fluororubber often focuses only on improving one aspect of performance. For example, CN110835446B improves the abrasion resistance and low-temperature flexibility of rubber by adding graphene and modified polyphenylene tetrafluoroethylene powder, but does not fully consider the sealing stability of the material under long-term compression. While the fluorinated copolymer compositions developed by AGC aim to improve high-temperature compression set, they do not specifically focus on the abrasion resistance and tear strength of the material. CN116410556A improves the compression set of fluororubber materials through hollow micropowders, but has limited improvement on abrasion resistance and tear strength.

[0004] Therefore, developing a fluororubber composite material that simultaneously possesses high wear resistance, high tear strength, and low compression set has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] To address the technical challenge of existing fluororubber materials in simultaneously achieving high wear resistance, high tear strength, and low compression set, this invention provides a fluororubber composite material with high wear resistance, high tear strength, and low compression set, along with its preparation method. By adding modified wear-resistant components, tear strength-enhancing components, and compression set-improving components, this invention solves the problem of traditional materials struggling to achieve both high tear strength and low compression set. It is suitable for use in high-speed rotating shaft rubber cups, sealing rings, and other movable seals operating in harsh environments such as gas turbines, and has broad industrial application prospects.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A fluororubber composite material with high wear resistance, high tear strength, and low compression set is made from the following raw materials in parts by weight: fluororubber raw rubber: 100 phr, reinforcing filler: 20~40 phr, wear-resistant modifier: 5~25 phr, tear strength improving component: 3~15 phr, compression set improving component: 1~10 phr, crosslinking system: 10~15 phr, and processing aid: 1~2 phr.

[0008] A method for preparing the above-mentioned fluororubber composite material with high wear resistance, high tear resistance, and low compression set includes the following steps:

[0009] Step 1, Mixing process:

[0010] Put the raw fluororubber into a two-roll mill and first pass it through a thin mill for plasticizing. After passing through the thin mill, add reinforcing filler, wear-resistant modifier, tear strength improving component, compression set improving component, crosslinking system, and processing aid. Mix all components evenly, control the roller temperature at 30~60℃, and the total mixing time is 20~40min.

[0011] Step 2, vulcanization process:

[0012] Step 2.1, First-stage vulcanization: Place the compounded rubber into the mold and carry out first-stage vulcanization in a flat vulcanizing machine. Control the temperature of the first-stage vulcanization at 160~180℃, the pressure at 5~10MPa, and the time at 10~20min; or the temperature and time of the first-stage vulcanization can be determined by a vulcanization curve test.

[0013] Step 2.2, Second-stage vulcanization: Place the sample after the first-stage vulcanization into an oven for second-stage vulcanization. The second-stage vulcanization adopts a stepped temperature increase program. The second-stage vulcanization parameters are: 0.5~1.5h from room temperature to 80~100℃, 0.5~1.5h from 80~100℃ to 140~160℃, 0.5~1.5h from 140~160℃ to 180~200℃, 0.5~1.5h from 180~200℃ to 240~260℃, and hold at 240~260℃ for 6~8h. The preferred second-stage vulcanization parameters are: 1h from room temperature to 100℃, 1h from 100℃ to 150℃, 1h from 150℃ to 200℃, 1h from 200℃ to 250℃, and hold at 250℃ for 8h.

[0014] Application of the above-mentioned high wear resistance, high tear resistance, and low compression set fluororubber composite material in the manufacture of seals and cushioning pads.

[0015] In the rubber composite material of the present invention, each component achieves a balanced improvement in three key properties through synergistic effects:

[0016] 1. Graphene and modified polyphenylene tetrafluoroethylene powder form a highly efficient wear-resistant network in a fluororubber matrix, reducing the coefficient of friction of the material;

[0017] 2. Polyzinc methacrylate and vinyl fluorosilicone oil modified carbon nanotubes construct a multi-layered reinforced structure, which improves the tear strength of the material by dispersing stress concentration points;

[0018] 3. The synergistic effect of phosphides and optimized crosslinking systems enables the rubber network to form a uniform and dense three-dimensional network structure, reducing the material's compression set performance.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. Multi-dimensional performance improvement: It simultaneously achieves high wear resistance (friction coefficient < 0.5), high tear strength (≥ 25 KN / m) and low compression set (compression set ≤ 15% at 200℃ × 70h), solving the technical problem that fluororubber materials are difficult to achieve in terms of three key properties.

[0021] 2. Component synergistic effect: Through the scientific ratio and optimized combination of various functional components, a significant synergistic enhancement effect is generated.

[0022] 3. Process adaptability: The material formulation is compatible with conventional rubber processing technology, requires no special equipment, and is suitable for industrial production. Detailed Implementation

[0023] The technical solution of the present invention will be further described below, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0024] This invention provides a fluororubber composite material with high wear resistance, high tear strength, and low compression set, made from the following raw materials in parts by weight: fluororubber raw rubber: 100 phr, reinforcing filler: 20-40 phr, wear-resistant modifier: 5-25 phr, tear strength improving component: 3-15 phr, compression set improving component: 1-10 phr, crosslinking system: 10-15 phr, processing aid: 1-2 phr, wherein:

[0025] The fluororubber raw material is made of one or two of vinylidene fluoride-hexafluoropropylene copolymer binary fluororubber and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer ternary fluororubber, and the Mooney viscosity (ML(1+10) 121℃) is controlled within the range of 25~65. The Mooney viscosity directly affects the processing performance and physical properties of the material. If the Mooney viscosity is too low, the strength of the compound will be insufficient, and if it is too high, it will affect the fluidity and filler dispersion.

[0026] The reinforcing filler is sprayed carbon black, preferably used at a dosage of 25-35 phr. It has a high specific surface area and good dispersibility, which can effectively improve the mechanical properties of the composite material.

[0027] The wear-resistant modified component is a mixture of graphene and modified polyphenylene tetroxide powder, with a ratio of graphene to modified polyphenylene tetroxide powder of 3~15:2~10. The modified polyphenylene powder is prepared by solution blending and modification of polyphenylene and tetroxide micropowder in the presence of silane coupling agent KH550. Graphene needs to be pre-dispersed with a small amount of fluororubber raw rubber. Graphene forms a highly efficient lubricating layer and reinforcing network in the fluororubber matrix, while the modified polyphenylene tetroxide micropowder further reduces the friction coefficient of the material. The synergistic effect of the two significantly improves the wear resistance of the material.

[0028] The tear strength enhancing component is a mixture of zinc polymethacrylate and vinyl fluorosilicone oil modified carbon nanotubes, with a ratio of 2~8:1~7. Among them, zinc polymethacrylate forms ionic crosslinking points during vulcanization, effectively dispersing the internal stress of the rubber; the modified carbon nanotubes improve their dispersibility and interfacial bonding strength in the matrix through surface modification.

[0029] The compression set improvement component is a phosphate compound with a melting point below 60°C. This phosphate compound melts into a liquid state at the mixing temperature, promoting the dispersion of fillers in the rubber matrix and optimizing the crosslinking network structure during vulcanization to form a more uniform network distribution, thereby reducing low compression set.

[0030] The crosslinking system is a mixture of vulcanizing agent, accelerator, and acid scavenger, wherein: the vulcanizing agent is bisphenol AF, the accelerator is BPP, and the acid scavenger is composed of active magnesium oxide and active calcium hydroxide, and the ratio of vulcanizing agent, accelerator, active magnesium oxide and active calcium hydroxide is 1.3~1.5:0.2~0.8:3~4:4~6;

[0031] The processing aid is fluorinated wax, and the preferred addition amount is 0.5~2 phr, which serves as both a processing aid and a release agent.

[0032] The preparation method of the above-mentioned fluororubber composite material with high wear resistance, high tear resistance, and low compression set includes the following steps:

[0033] Step 1, Pre-treatment process:

[0034] Step 11: Preparation of modified polyphenylene tetroxide micro powder: Polyphenylene and tetroxide micro powder are mixed at a mass ratio of 1:2, and 1-3% of silane coupling agent KH550 is added. The mixture is reacted at 80-100℃ for 2-4 hours in the presence of a solvent, and then dried and pulverized.

[0035] Step 12, Preparation of modified carbon nanotubes: Place carbon nanotubes in an ethanol solution of vinyl fluorosilicone oil, sonicate for 1-2 hours, filter and dry to obtain vinyl fluorosilicone oil modified carbon nanotubes.

[0036] Step 2, Mixing process:

[0037] The raw fluororubber is put into a two-roll mill and plasticized first. After the plasticizing is completed, acid absorber, reinforcing filler, wear-resistant modifier, tear strength improver, compression set improver, processing aid, vulcanizing agent and accelerator are added in sequence. During the mixing process, the roller temperature is controlled at 30~60℃ by switching on and off the cooling water. All components are mixed evenly, and the total mixing time is controlled at 20~40 minutes.

[0038] Step 3, vulcanization process:

[0039] Step 31, First-stage vulcanization: Place the compounded rubber into the mold and perform first-stage vulcanization in a flat vulcanizing machine. Vulcanization conditions: temperature 170℃, pressure 5~10MPa, time 10~20min.

[0040] Step 32, Second-stage vulcanization: The sample after the first-stage vulcanization is placed in an oven for second-stage vulcanization. The second-stage vulcanization adopts a stepped temperature increase program: 1 hour from room temperature to 100℃, 1 hour from 100℃ to 150℃, 1 hour from 150℃ to 200℃, 1 hour from 200℃ to 250℃, and then held at 250℃ for 8 hours. The purpose of the second-stage vulcanization is to eliminate internal stress in the material, improve the rubber cross-linking network structure, and further enhance the material's compression set performance and high-temperature stability.

[0041] To verify the technical effects of the present invention, a performance comparison is provided below.

[0042] Table 1. Test and comparative formulations of fluororubber composite materials (parts by weight): phr

[0043]

[0044] Fluororubber raw rubber: 100 phr, reinforcing filler: 20~40 phr, abrasion-resistant modifier: 5~25 phr, tear strength enhancer: 3~15 phr, compression set improver: 1~10 phr, crosslinking system: 10~15 phr, processing aids: 1~2 phr

[0045] Comparative Example 2 used the formulation of Example 1 in CN110835446B and conducted physicochemical tests on the fluororubber composite materials in Table 1 and Comparative Example 2. The results are shown in Table 2.

[0046] Table 2

[0047]

[0048] Physicochemical test reference standards:

[0049] (1) Hardness test: The test shall be conducted in accordance with ASTM D 2240;

[0050] (2) Tensile strength and elongation at break tests: The tests shall be conducted in accordance with ASTM D 412;

[0051] (3) Tear strength test: The test shall be conducted in accordance with ASTM D 624;

[0052] (4) Compression set test: The test shall be conducted in accordance with ASTM D 395;

[0053] (5) Abrasion test: The test shall be conducted in accordance with ASTM D 5963.

[0054] As shown in Table 2, the fluororubber composite materials (numbered 1-3) prepared by this invention are significantly superior to the traditional fluororubber formulation (Comparative Example 1) and the single-modified fluororubber formulation (Comparative Example 2) in terms of three key properties: abrasion resistance, tear strength, and compression set. This indicates that this invention successfully achieves a balanced improvement in the three key properties through the synergistic effect of multiple components.

[0055] In summary, this invention successfully developed a fluororubber composite material with high wear resistance, high tear strength, and low compression set through the synergistic effect of multiple components. By optimizing the dispersibility and interfacial bonding of fillers, this material significantly improves the tear strength, abrasion resistance, and compression set of fluororubber, solving the technical challenge of existing fluororubbers failing to achieve these three key properties simultaneously. It is particularly suitable for manufacturing high-performance seals and other rubber products, exhibiting longer service life and more reliable performance under harsh operating conditions.

Claims

1. A fluororubber composite material with high wear resistance, high tear resistance, and low compression set, characterized in that... The fluororubber composite material is made from the following raw materials: fluororubber raw rubber: 100 phr, reinforcing filler: 20~40 phr, abrasion-resistant modifier: 5~25 phr, tear strength improving component: 3~15 phr, compression set improving component: 1~10 phr, crosslinking system: 10~15 phr, and processing aid: 1~2 phr.

2. The fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 1, characterized in that... The fluororubber raw material is one or two of vinylidene fluoride-hexafluoropropylene copolymer binary fluororubber and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer ternary fluororubber. The reinforcing filler is sprayed carbon black, the compression set improvement component is phosphate, and the processing aid is fluorowax.

3. The fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 1, characterized in that... The wear-resistant modified component is a mixture of graphene and modified polyphenylene tetrafluoroethylene powder, with a ratio of 3~15:2~10.

4. The fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 1, characterized in that... The tear strength enhancing component is a mixture of zinc polymethacrylate and vinyl fluorosilicone oil modified carbon nanotubes, with a ratio of 2~8:1~7.

5. The fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 1, characterized in that... The crosslinking system is a mixture of vulcanizing agent, accelerator, and acid scavenger, wherein: the vulcanizing agent is bisphenol AF, the accelerator is BPP, and the acid scavenger is composed of active magnesium oxide and active calcium hydroxide, and the ratio of vulcanizing agent, accelerator, active magnesium oxide and active calcium hydroxide is 1.3~1.5:0.2~0.8:3~4:4~6.

6. A method for preparing a fluororubber composite material with high wear resistance, high tear resistance, and low compression set as described in any one of claims 1-5, characterized in that... The method includes the following steps: Step 1, Mixing process: The raw fluororubber is put into a two-roll mill and plasticized in a thin pass. After the thin pass is completed, reinforcing filler, wear-resistant modifier, tear strength improving component, compression set improving component, crosslinking system, and processing aid are added and all components are mixed evenly. Step 2, vulcanization process: Step 2.1, First-stage vulcanization: Place the compounded rubber into the mold and perform first-stage vulcanization in a flat vulcanizing machine; Step 2.2, Second-stage vulcanization: Place the sample after the first-stage vulcanization into an oven for second-stage vulcanization.

7. The method for preparing the fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 6, characterized in that... In step 1, the roller temperature is controlled at 30~60℃ and the total mixing time is 20~40min.

8. The method for preparing the fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 6, characterized in that... In step 2.1, the temperature of the first-stage vulcanization is controlled at 160~180℃, the pressure at 5~10MPa, and the time at 10~20min; or the temperature and time of the first-stage vulcanization are determined by a sulfur curve test. In step 2.2, the second-stage vulcanization adopts a stepped temperature increase program, and the parameters for the second-stage vulcanization are: 0.5~1.5h from room temperature to 80~100℃, 0.5~1.5h from 80~100℃ to 140~160℃, 0.5~1.5h from 140~160℃ to 180~200℃, 0.5~1.5h from 180~200℃ to 240~260℃, and 240~260℃ is kept constant for 6~8h.

9. The method for preparing the fluororubber composite material with high wear resistance, high tear resistance, and low compression set according to claim 8, characterized in that... The preferred parameters for the two-stage vulcanization process are: 1 hour to 100°C, 1 hour to 150°C, 1 hour to 200°C, 1 hour to 250°C, and 250°C constant temperature for 8 hours.

10. The application of a fluororubber composite material with high wear resistance, high tear resistance, and low compression set as described in any one of claims 1-5 in the manufacture of seals and cushioning pads.

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