High-temperature-yellowing-resistant fluororubber compound as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-yellowing-resistant fluororubber compound as well as a preparation method and application thereof, and belongs to the field of chemical materials. The fluororubber compound comprises the following raw materials: modified diatomite and fluororubber; the modified diatomite is prepared from the following raw materials in parts by weight: 2 to 8 parts of amino silane, 2 to 8 parts of a multi-acyl chloride cross-linking agent and 80 to 100 parts of diatomite, and the modified diatomite is prepared from the following raw materials in parts by weight: 2 to 8 parts of amino silane, 2 to 8 parts of the multi-acyl chloride cross-linking agent and 80 to 100 parts of diatomite. The amino silane reacts with the diatomite and then reacts with the multi-acyl chloride cross-linking agent to obtain the modified diatomite, the modified diatomite is used for modifying the fluororubber, the initial strength, the high-temperature strength attenuation resistance and the high-temperature yellowing resistance of the fluororubber can be remarkably improved, and the fluororubber compound is simple in formula, high in safety to a human body and suitable for popularization and application. And the method has a wide application prospect in the field of intelligent wearing.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials, specifically relating to a high-temperature resistant yellowing fluororubber compound, its preparation method, and its uses. Background Technology

[0002] Smartwatches are gaining popularity among consumers due to their lightweight portability and diverse functionalities. Their rubber straps, in particular, are increasingly favored for their skin-friendliness, comfort, and durability. Compared to leather or steel straps, rubber straps are lighter, more comfortable to wear, and less prone to freezing in winter and odor from sweat in summer. The introduction of fluoroelastomers into the smart wearable market has further expanded the market for rubber straps.

[0003] Fluororubber is a special type of synthetic rubber, characterized by the addition of fluorine atoms to its main and side chains, giving it unparalleled superior properties compared to other rubbers. The introduction of fluorine atoms enhances its antioxidant properties while also providing heat resistance, aging resistance, and corrosion resistance. It maintains its softness and elasticity between high temperatures of 300°C and -20°C. It also possesses waterproof, stain-resistant, and UV-resistant properties, is not easily deformed or hardened, has a long service life, and exhibits excellent tensile and tear resistance, making it wear-resistant and able to withstand considerable pressure during outdoor activities.

[0004] Despite the aforementioned advantages, fluororubber still faces some challenges, such as its tendency to yellow at high temperatures, which limits its application in smart wearables. The literature "Silane Coupling Agent Modified Silica and Diatomaceous Earth Filled Fluororubber Composites" utilizes 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide as filler modifiers to improve the compatibility between diatomaceous earth and silica fillers and fluororubber, making the fluororubber more conducive to heat absorption and accumulation, thus improving its thermal properties. However, this approach only improves the heat resistance of fluororubber and does not solve the problem of yellowing at high temperatures. Chinese patent application CN115216067A discloses an anti-yellowing antioxidant for transparent rubber and its preparation method. This method improves the long-term antioxidant and anti-yellowing properties of fluororubber by adding hindered phenolic antioxidants, benzotriazole UV absorbers, and thioester antioxidants. However, the anti-yellowing agents added in this scheme are small-molecule organic compounds, which are easily decomposed or migrated during transportation, long-term storage, and prolonged high temperatures, resulting in poor anti-yellowing durability. Furthermore, they are toxic, posing safety concerns if used in wearable products.

[0005] With the rapid development of the smart wearable field, people have higher requirements for the performance of fluororubber watch straps in terms of resistance to yellowing and breakage during long-term wear, as well as their safety to the human body. Therefore, it is of great significance to improve the application market of fluororubber with good tensile strength and tear resistance, good resistance to high temperature strength decay and high temperature yellowing, and safety to the human body. Summary of the Invention

[0006] The purpose of this invention is to provide a high-temperature resistant yellowing fluororubber compound, its preparation method, and its uses.

[0007] This invention provides a fluororubber compound comprising the following parts by weight of raw materials: 70-120 parts of modified diatomaceous earth and 200-400 parts of fluororubber; wherein the modified diatomaceous earth is prepared from the following parts by weight of raw materials: 2-8 parts of aminosilane, 2-8 parts of polyacrylamide crosslinking agent, and 80-100 parts of diatomaceous earth.

[0008] Furthermore, the modified diatomaceous earth is prepared from the following raw materials in parts by weight: 2-6 parts of aminosilane, 2-6 parts of polyacrylamide crosslinking agent, and 90 parts of diatomaceous earth.

[0009] Furthermore, the weight ratio of the aminosilane to the polyacrylamide crosslinking agent is 1:1.

[0010] Further, the aminosilane includes N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, or N-(2-aminoethyl)-3-aminopropyltriethoxysilane; the polyacrylamide crosslinking agent includes trimesoyl chloride, trimesoyl chloride, terephthaloyl chloride, or isophthaloyl chloride.

[0011] Furthermore, fluororubber compounds also include the following raw materials: crosslinking agents, vulcanizing agents, metal oxides, or titanium dioxide.

[0012] Further, the fluororubber compound is made from the following raw materials in parts by weight: 80-100 parts modified diatomaceous earth, 250-350 parts fluororubber, 10-15 parts crosslinking agent, 2-10 parts vulcanizing agent, 10-20 parts metal oxide, and 10-20 parts titanium dioxide; the crosslinking agent includes triallyl isocyanurate, triallyl cyanurate, or N,N'-m-phenylenebismaleimide; the vulcanizing agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide, di-tert-butyl peroxide, or 2,4-dichlorobenzoyl peroxide; the metal oxide includes zinc oxide, magnesium oxide, calcium oxide, bismuth oxide, or hydrotalcite.

[0013] Furthermore, the fluororubber compound is made from the following raw materials in parts by weight: 90 parts modified diatomaceous earth, 300 parts fluororubber, 12 parts crosslinking agent, 6 parts vulcanizing agent, 15 parts metal oxide, and 15 parts titanium dioxide.

[0014] This invention also provides a method for preparing fluororubber compound, characterized by comprising the following steps: (1) Weigh out aminosilane by weight and dissolve it in an organic solvent to obtain a mixed solution. Then pour the mixed solution into diatomaceous earth, ball mill it and heat treat it. Then add polyacrylamide crosslinking agent, mix and stir evenly and ball mill to obtain modified diatomaceous earth. (2) Mix the modified diatomaceous earth with fluororubber according to the weight parts to obtain fluororubber compound.

[0015] According to the preparation method of claim 8, the organic solvent includes at least one of anhydrous methanol, anhydrous ethanol, acetone, and isopropanol.

[0016] This invention also provides the use of fluororubber compounds in the field of smart wearables.

[0017] This invention first reacts aminosilane with diatomaceous earth, and then reacts it with a polyacrylamide crosslinking agent to obtain modified diatomaceous earth. Using this modified diatomaceous earth to modify fluororubber can significantly improve the initial strength, high-temperature strength decay resistance, and high-temperature yellowing resistance of fluororubber. The modified diatomaceous earth can also connect with fluororubber through hydrogen bonds, which helps in the adhesion of fluororubber watch straps and gives fluororubber higher elasticity. Furthermore, the fluororubber compound has a simple formulation and high safety for the human body, making it a promising candidate for application in the field of smart wearables.

[0018] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0019] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Detailed Implementation

[0020] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0021] The fluororubber used in the specific implementation plan is ternary fluororubber purchased from Zhejiang Juhua Co., Ltd.

[0022] Example 1: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound: (1) Weigh 2g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and dissolve it in 1g of anhydrous methanol solution to obtain a mixed solution. Then pour the mixed solution into 90g of diatomaceous earth and ball mill for 30min. After that, take it out and place it in an 80℃ oven for 1h to allow it to react fully. Then add 2g of trimesoyl chloride, mix and stir evenly, and place it in a ball mill for 30min to obtain modified diatomaceous earth. (2) The modified diatomaceous earth was mixed with 300g of fluororubber, 12g of triallyl isocyanurate, 6g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 15g of zinc oxide and 15g of titanium dioxide in a mixer. After mixing, the mixture was sheeted out by a rolling mill to obtain fluororubber compound.

[0023] 2. Preparation of fluororubber compound watch straps The fluororubber compound is cut into long strips, then placed in a mold and hot-pressed at 180℃ and 15MPa for 10 minutes. Then it is placed in an oven at 180℃ for 4 hours to obtain the final product.

[0024] Example 2: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound: (1) Weigh 4g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and dissolve it in 3g of anhydrous methanol solution to obtain a mixed solution. Then pour the mixed solution into 90g of diatomaceous earth and ball mill for 30min. After that, take it out and place it in an 80℃ oven for 1h to allow it to react fully. Then add 4g of trimesoyl chloride, mix and stir evenly, and place it in a ball mill for 30min to obtain modified diatomaceous earth. (2) is the same as step (2) in Example 1.

[0025] 2. Preparation of fluororubber compound watch straps Same as Example 1.

[0026] Example 3: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound: (1) Weigh 6g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and dissolve it in 4g of anhydrous methanol solution to obtain a mixed solution. Then pour the mixed solution into 90g of diatomaceous earth and ball mill for 30min. After that, take it out and place it in an 80℃ oven for 1h to allow it to react fully. Then add 6g of trimesoyl chloride, mix and stir evenly, and place it in a ball mill for 30min to obtain modified diatomaceous earth. (2) is the same as step (2) in Example 1.

[0027] 2. Preparation of fluororubber compound watch straps Same as Example 1.

[0028] Example 4: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound: (1) Weigh 8g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and dissolve it in 5g of anhydrous methanol solution to obtain a mixed solution. Then pour the mixed solution into 90g of diatomaceous earth and ball mill for 30min. After that, take it out and place it in an 80℃ oven for 1h to allow it to react fully. Then add 8g of trimesoyl chloride, mix and stir evenly, and place it in a ball mill for 30min to obtain modified diatomaceous earth. (2) is the same as step (2) in Example 1.

[0029] 2. Preparation of fluororubber compound watch straps Same as Example 1.

[0030] Comparative Example 1: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound (without adding trimesoyl chloride): (1) Weigh 4g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and dissolve it in 3g of anhydrous methanol solution to obtain a mixed solution. Then pour the mixed solution into 90g of diatomaceous earth, ball mill for 30min, and then take it out and place it in an 80℃ oven for 1h to allow it to react fully and obtain aminosilane modified diatomaceous earth. (2) The aminosilane modified diatomaceous earth was mixed with 300g of fluororubber, 12g of crosslinking agent, 6g of vulcanizing agent, 15g of metal oxide and 15g of titanium dioxide in a mixer. After mixing, the mixture was sheeted out by a rolling mill to obtain fluororubber compound.

[0031] 2. Preparation of fluororubber compound watch straps Same as Example 1.

[0032] Comparative Example 2: Preparation of Fluororubber Compound and its Watch Strap 1. Preparation of fluororubber compound (unmodified diatomaceous earth): 90g of diatomaceous earth, 300g of fluororubber, 12g of crosslinking agent, 6g of vulcanizing agent, 15g of metal oxide, and 15g of titanium dioxide were mixed together in an internal mixer. After mixing, the mixture was sheeted out using a two-roll mill to obtain fluororubber compound.

[0033] 2. Preparation of fluororubber compound watch straps Same as Example 1.

[0034] Experimental Example 1: Strength and Yellowing Rate Test of Fluororubber Compound Watch Straps 1. Experimental Methods (1) Strap strength test: GB / T 528 standard.

[0035] (2) Yellowing rate test of watch strap: ASTM D1148 standard.

[0036] 2. Experimental Results As shown in Table 1, after high-temperature aging at 180℃ for 70h, the fluororubber compound watch straps of Examples 1-4 showed a significant reduction in strength decay rate and yellowing rate compared to Comparative Examples 1-2, proving that the fluororubber compound watch straps prepared by the method of the present invention have better resistance to high-temperature strength decay and high-temperature yellowing.

[0037] In Comparative Example 1, the initial strength of the fluororubber compound watch strap prepared compared to Comparative Example 2 was improved. After high-temperature aging at 180℃ / 70h, its strength decay rate and yellowing rate decreased, indicating that aminosilane-modified diatomaceous earth can improve the initial strength, high-temperature strength decay resistance, and high-temperature yellowing resistance of the fluororubber compound watch strap. In Example 2, the initial strength of the fluororubber compound watch strap prepared without the addition of trimesoyl chloride in Comparative Example 1 was increased by 13.3%. After high-temperature aging at 180℃ / 70h, its strength decay rate decreased from 22% to 14%, and its yellowing rate decreased from 39% to 28%. This fully demonstrates that the modified diatomaceous earth obtained by further adding trimesoyl chloride to aminosilane-modified diatomaceous earth can significantly improve the initial strength, high-temperature strength decay resistance, and high-temperature yellowing resistance of the fluororubber compound watch strap.

[0038] In Example 4, the addition of aminosilane and trimesoyl chloride was relatively large, resulting in a significant decrease in the initial strength of the fluororubber compound watch strap. This indicates that when the addition of aminosilane and trimesoyl chloride exceeds a certain amount, it will be detrimental to the initial performance of the fluororubber compound watch strap. Only when the addition of aminosilane and trimesoyl chloride is in a specific amount can a fluororubber compound watch strap with excellent initial strength, resistance to high-temperature strength decay, and resistance to high-temperature yellowing be obtained.

[0039] Table 1 Initial strength of fluororubber compound watch straps and their strength decay rate and yellowing rate after high-temperature aging. In summary, this invention first reacts aminosilane with diatomaceous earth, and then reacts it with trimesoyl chloride to obtain modified diatomaceous earth. By adding this modified diatomaceous earth to prepare a fluororubber compound watch strap for smart wearables, it exhibits significantly improved initial strength, resistance to high-temperature strength decay, and resistance to high-temperature yellowing. Furthermore, the fluororubber compound formulation is simple and highly safe for human use. Specifically, the fluororubber compound watch strap prepared by adding 2-6 parts of aminosilane and 2-6 parts of trimesoyl chloride simultaneously improves initial strength, resistance to high-temperature strength decay, and resistance to high-temperature yellowing.

Claims

1. A fluororubber compound, characterized in that, It comprises the following raw materials in parts by weight: 70-120 parts modified diatomaceous earth and 200-400 parts fluororubber; the modified diatomaceous earth is prepared from the following raw materials in parts by weight: 2-8 parts aminosilane, 2-8 parts polyacrylamide crosslinking agent, and 80-100 parts diatomaceous earth.

2. The fluororubber compound according to claim 1, characterized in that, The modified diatomaceous earth is prepared from the following raw materials in parts by weight: 2-6 parts aminosilane, 2-6 parts polyacrylamide crosslinking agent, and 90 parts diatomaceous earth.

3. The fluororubber compound according to any one of claims 1 to 2, characterized in that, The weight ratio of the aminosilane to the polyacrylamide crosslinking agent is 1:

1.

4. The fluororubber compound according to any one of claims 1 to 2, characterized in that, The aminosilane includes N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, or N-(2-aminoethyl)-3-aminopropyltriethoxysilane; the polyacrylamide crosslinking agent includes trimesoyl chloride, trimesoyl chloride, terephthaloyl chloride, or isophthaloyl chloride.

5. The fluororubber compound according to claim 1, characterized in that, It also includes the following raw materials: crosslinking agent, vulcanizing agent, metal oxide or titanium dioxide.

6. The fluororubber compound according to claim 5, characterized in that, It is made from the following raw materials in parts by weight: 80-100 parts modified diatomaceous earth, 250-350 parts fluororubber, 10-15 parts crosslinking agent, 2-10 parts vulcanizing agent, 10-20 parts metal oxide, and 10-20 parts titanium dioxide; the crosslinking agent includes triallyl isocyanurate, triallyl cyanurate, or N,N'-m-phenylenebismaleimide; the vulcanizing agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide, di-tert-butyl peroxide, or 2,4-dichlorobenzoyl peroxide; the metal oxide includes zinc oxide, magnesium oxide, calcium oxide, bismuth oxide, or hydrotalcite.

7. The fluororubber compound according to claim 6, characterized in that, It is made from the following raw materials in parts by weight: 90 parts modified diatomaceous earth, 300 parts fluororubber, 12 parts crosslinking agent, 6 parts vulcanizing agent, 15 parts metal oxide, and 15 parts titanium dioxide.

8. The method for preparing the fluororubber compound according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Weigh out aminosilane by weight and dissolve it in an organic solvent to obtain a mixed solution. Then pour the mixed solution into diatomaceous earth, ball mill it and heat treat it. Then add polyacrylamide crosslinking agent, mix and stir evenly and ball mill to obtain modified diatomaceous earth. (2) Mix the modified diatomaceous earth with fluororubber according to the weight parts to obtain fluororubber compound.

9. The preparation method according to claim 8, characterized in that, The organic solvent includes at least one of anhydrous methanol, anhydrous ethanol, acetone, and isopropanol.

10. The use of the fluororubber compound according to any one of claims 1 to 7 in the field of smart wearables.

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