Modified polysiloxane raw material composition, nitrile group-containing fluoropolysiloxane, method for producing the same, and modified silica gel composition containing the same

Abstract

The present application provides a modified polysiloxane raw material composition, a nitrile group-containing fluoropolysiloxane, a method for preparing the same, and a modified silica gel composition containing the same. The nitrile group-containing fluoropolysiloxane can be blended with general-purpose silicone rubber in any ratio and chemically crosslinked, and form a triazine ring or a nitrogen-containing five-membered ring having heat resistance, thereby improving the high-temperature resistance of the polysiloxane elastomer. Furthermore, the polysiloxane elastomer contains a perfluoropolyether chain segment in the molecular chain, thereby effectively improving the resistance to polar solvents of the material.

Description

Technical Field

[0001] This invention relates to a modified polysiloxane raw material composition, a nitrile-containing fluorinated polysiloxane, its preparation method, and a modified silicone composition containing the same, belonging to the field of polymer materials. Background Technology

[0002] In recent years, wide-temperature-range (-100℃ to +350℃) polymer materials have gained favor among researchers, with demand in new energy vehicles, artificial intelligence equipment, and chemical equipment. For example, polysiloxanes have an operating temperature range of -70℃ to +250℃; fluorinated polysiloxanes have an operating temperature range of -60℃ to +220℃; perfluoroether rubbers have an operating temperature range of -30℃ to +350℃; and perfluoropolyether-based elastomers have an operating temperature range of -80℃ to +320℃, and so on. Among these, polysiloxanes are inexpensive and used most extensively, but have poor resistance to polar solvents. Perfluoropolymers, on the other hand, have the best resistance to polar solvents, but are expensive and mostly used in high-end applications. Currently, commercially available phenyl silicone rubber has an operating temperature range of -110℃ to +300℃, indicating that the benzene ring can improve the heat resistance of polysiloxane materials. However, due to the rigidity of the benzene ring, the material is relatively difficult to process. Therefore, it is necessary to provide a new silicone rubber modifier to address these issues. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a modified polysiloxane raw material composition, a nitrile-containing fluorinated polysiloxane, a method for preparing the same, and a modified silicone composition containing the same. This nitrile-containing fluorinated polysiloxane can be blended and chemically crosslinked with general-purpose liquid silicone rubber in any proportion to form a heat-resistant triazine ring or a nitrogen-containing five-membered ring, thereby improving the high-temperature resistance of the polysiloxane elastomer. Furthermore, the molecular chain of this polysiloxane elastomer contains perfluoropolyether segments, effectively improving its resistance to polar solvents.

[0004] To achieve the above objectives, the present invention provides a modified polysiloxane raw material composition comprising a fluorinated polysiloxane and a nitrile-containing olefin compound; wherein the fluorinated polysiloxane has the structure R f -bR;R f R represents a perfluoropolyether segment, R represents a polysiloxane segment, and b represents a block; the nitrile-containing olefin compound is selected from one or more combinations of acrylonitrile, allyl nitrile, cyclohexenyl acetonitrile, and 5-hexenonitrile.

[0005] The nitrile-containing olefin compound can subsequently introduce cyclic nitrile groups (-CN) onto the polysiloxane, thereby improving the polysiloxane's processability. Based on the above-mentioned modified polysiloxane raw material composition, the resulting nitrile-containing fluorinated polysiloxane can be blended and chemically crosslinked with common liquid silicone rubber in any proportion. Furthermore, it forms a heat-resistant triazine ring or a nitrogen-containing five-membered ring under the catalysis of an amino-containing organic compound, improving the high-temperature resistance of the polysiloxane elastomer. Moreover, the presence of perfluoropolyether segments in the molecular chain of this polysiloxane elastomer effectively improves its resistance to polar solvents.

[0006] Furthermore, the molar ratio of the nitrile-containing olefin compound to the fluorinated polysiloxane is 2 to 10:1.

[0007] Furthermore, in the fluorinated polysiloxane, the raw material source of the perfluoropolyether segment includes one or more combinations of K-type perfluoropolyether, D-type perfluoropolyether, Y-type perfluoropolyether, and Z-type perfluoropolyether. In the fluorinated polysiloxane, the raw material source of the polysiloxane segment includes one or more combinations of terminal silane-hydrogen polysiloxane, side-silane-hydrogen polysiloxane, and terminal mercapto polysiloxane. The fluorinated polysiloxane can be obtained by polymerizing the above-mentioned perfluoropolyether segment raw material and the polysiloxane segment raw material (the preparation method can be found in the following literature: Feng Yuzhi et al. Performance of double-terminated silane-hydrogen perfluoropolyether-b-polysiloxane in nitrile rubber [J]. Fine Chemicals, 2023(3): 673-696.), or it can be directly purchased commercially. This is something that those skilled in the art can obtain based on existing known technology, and will not be elaborated here.

[0008] Furthermore, the modified polysiloxane raw material composition also includes the fluorocarbon solvent, which is selected from one or more combinations of nonafluorobutyl ethyl ether, nonafluorobutyl methyl ether, trifluorotoluene, 1,3-bis(trifluoromethyl)benzene, perfluorocyclic ethers and perfluorohexane.

[0009] Furthermore, the modified polysiloxane raw material composition also includes a catalyst selected from one or more combinations of Castells catalyst, Speier catalyst, benzoyl peroxide, di-tert-butyl peroxide, and platinum catalyst (e.g., an isopropanol solution of chloroplatinic acid). The amount of the catalyst is 0.01 to 10 wt% of the weight of the modified polysiloxane raw material composition.

[0010] Furthermore, the modified polysiloxane raw material composition also includes an organic alcohol compound; the organic alcohol compound is selected from one or more combinations of methanol, ethanol, isopropanol, tert-butanol, ethylene glycol, polyethylene glycol, and propylene glycol.

[0011] The present invention also provides a method for preparing nitrile-containing fluorinated polysiloxanes, using the aforementioned modified polysiloxane raw material composition. The preparation method includes: mixing fluorinated polysiloxanes and nitrile-containing olefin compounds to carry out a chemical reaction to obtain a product system, and separating the nitrile-containing fluorinated polysiloxanes from the product system.

[0012] Based on this preparation method, this invention prepares fluorinated polysiloxane materials with nitrile groups at different crosslinking sites. Furthermore, the preparation method is simple, clear, easy to operate, and yields high product yields.

[0013] Further, the preparation method includes the following steps: mixing the fluorinated polysiloxane, the nitrile-containing olefin compound, the fluorocarbon solvent and the catalyst to carry out the chemical reaction to obtain the product system; adding an organic alcohol compound to the product system, then allowing the product system to separate and stand, taking out the lower layer liquid for distillation to obtain the nitrile-containing fluorinated polysiloxane.

[0014] Furthermore, the reaction temperature for the chemical reaction between the fluorinated polysiloxane and the nitrile-containing olefin compound is 25–170°C, and the reaction time is 1–72 h.

[0015] The present invention also provides a nitrile-based fluorinated polysiloxane, which is prepared by the aforementioned preparation method.

[0016] The present invention also provides a modified silicone composition comprising the aforementioned nitrile-containing fluorinated polysiloxane and silicone rubber.

[0017] Furthermore, the modified silicone composition may also include an amino-containing organic compound; said amino-containing organic compound is selected from one or more combinations of 4,4'-diaminodiphenyl sulfone, aminopropyltriethoxysilane, and amino silicone oil. In some optional embodiments, the modified silicone composition may also include commonly used silicone rubber additives, such as hydrophobic silica (TS530), etc. The type and amount of additives can be adjusted by those skilled in the art, and will not be elaborated here. In some optional embodiments, the modified silicone composition may also include a crosslinking agent, such as 2,5-dimethyl-2,5-bis(tert-butylperoxy), etc. The type and amount of crosslinking agent can be adjusted by those skilled in the art, and will not be elaborated here. Attached Figure Description

[0018] Figure 1 The infrared spectrum of terminal nitrile perfluoropolyether-b-polysiloxane in an embodiment of the present invention is shown. Detailed Implementation

[0019] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0020] The raw materials for the following examples are sourced from:

[0021] Double-ended perfluorosilane-b-polysiloxane:

[0022]

[0023] The molecular weight is approximately 6800, and the molecular weight of the perfluoropolyether segment is approximately 1700. It is an industrial grade product manufactured by PetroChina (Shanghai) New Materials Research Institute Co., Ltd.

[0024] In-chain perfluorosilane-β-polysiloxane:

[0025]

[0026] The perfluoropolyether segment has a molecular weight of approximately 1700 and a silicon hydrogen content of 0.06% by weight, is industrial grade, and is manufactured by CNPC (Shanghai) New Materials Research Institute Co., Ltd.; and the perfluoropolyether segment has a molecular weight of approximately 1700 and a silicon hydrogen content of 0.12% by weight, is industrial grade, and is also manufactured by CNPC (Shanghai) New Materials Research Institute Co., Ltd.

[0027] m-Difluorotoluene, acrylonitrile, allyl nitrile, 4,4'-diaminodiphenyl sulfone, aminopropyltriethoxysilane, 2,5-dimethyl-2,5-bis(tert-butylperoxy): reagent grade, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0028] Amino silicone oil (OFX-8040A): Industrial grade, Dow Corning.

[0029] Hydrophobic silica (TS530), industrial grade, Cabot.

[0030] Methyl vinyl silicone rubber (MVQ, molecular weight 630,000, vinyl content 0.18%), industrial grade, Nanjing Dongjue.

[0031] Example 1

[0032] 100 g of bipolar perfluoropolyether-b-polysiloxane (molecular weight approximately 6800, perfluoropolyether segment molecular weight approximately 1700), 40 mL of m-difluorotoluene, 2 g of acrylonitrile, and 1 mL of isopropanol solution of chloroplatinic acid (Pt content 200 ppm) were placed in a three-necked flask. The mixture was heated to 50 °C and stirred for 2 h, then heated to 70 °C and stirred for 36 h. Subsequently, unreacted acrylonitrile was removed by vacuum distillation at 70 °C. After cooling to room temperature, 20 mL of methanol was added, and the mixture was stirred rapidly for 1 min (stirring speed 800 rpm). The mixture was transferred to a separatory funnel and allowed to stand. The lower layer was collected, and m-difluorotoluene was removed by vacuum distillation to obtain 98 g of nitrile-terminated perfluoropolyether-b-polysiloxane, designated FSCN-1, with the following structural formula:

[0033]

[0034] The infrared spectrum of FSCN-1 is as follows: Figure 1 As shown, at 2128cm -1 A distinct nitrile vibration stretching peak (-CN) was observed. The infrared spectrum of the product was measured using a Bruker Tensor 27 Fourier transform infrared spectrometer (FTIR) with attenuated total reflectance (ATR) at a resolution of 3 cm⁻¹. -1 Scanning range 4000-500cm -1 Sample preparation: coating method and tableting method; reference material: potassium bromide.

[0035] Example 2

[0036] 100 g of bipolar perfluoropolyether-b-polysiloxane (molecular weight approximately 6800, perfluoropolyether segment molecular weight approximately 1700), 40 mL of m-difluorotoluene, 3 g of allyl nitrile, and 1 mL of isopropanol solution of chloroplatinic acid (Pt content 200 ppm) were placed in a three-necked flask. The mixture was heated to 50 °C and stirred for 2 h, then heated to 70 °C and stirred for 12 h. Afterward, the mixture was cooled to room temperature at 70 °C, and 20 mL of methanol was added. The mixture was stirred rapidly for 1 min (stirring speed 800 rpm) and transferred to a separatory funnel. After standing, the lower layer was collected, and the m-difluorotoluene and unreacted allyl nitrile were removed by vacuum distillation to obtain 99 g of acrylonitrile-terminated perfluoropolyether-b-polysiloxane, designated FSCN-2, with the following structural formula:

[0037]

[0038] Example 3

[0039] 50 g of silane-containing perfluoropolyether-b-polysiloxane (perfluoropolyether segment molecular weight approximately 1700, silane content 0.06%), 20 mL of m-difluorotoluene, 3 g of allyl nitrile, and 1 mL of isopropanol solution of chloroplatinic acid (Pt content 200 ppm) were placed in a three-necked flask. The mixture was heated to 50 °C and stirred for 2 h, then heated to 70 °C and stirred for 12 h. After cooling to room temperature, 20 mL of methanol was added, and the mixture was rapidly stirred for 1 min (stirring speed 800 rpm). The mixture was then transferred to a separatory funnel. After standing, the lower layer was collected, and the m-difluorotoluene and unreacted allyl nitrile were removed by vacuum distillation to obtain 45 g of cyanoyl perfluoropolyether-b-polysiloxane, designated FSCN-3, with the following structural formula:

[0040]

[0041] Example 4

[0042] 50 g of silane-containing perfluoropolyether-b-polysiloxane (perfluoropolyether segment molecular weight approximately 1700, silane content 0.12%), 20 mL of m-difluorotoluene, 4 g of allyl nitrile, and 1 mL of isopropanol solution of chloroplatinic acid (Pt content 200 ppm) were placed in a three-necked flask. The mixture was heated to 50 °C and stirred for 2 h, then heated to 70 °C and stirred for 12 h. After cooling to room temperature, 20 mL of methanol was added, and the mixture was rapidly stirred for 1 min (stirring speed 800 rpm). The mixture was then transferred to a separatory funnel. After standing, the lower layer was collected, and the m-difluorotoluene and unreacted allyl nitrile were removed by vacuum distillation to obtain 43 g of cyanoyl perfluoropolyether-b-polysiloxane, designated FSCN-4, with the following structural formula:

[0043]

[0044] Performance characterization:

[0045] Example Group: FSCN-1, FSCN-2, FSCN-3, and FSCN-4 from Examples 1 to 4 were mixed with methyl vinyl silicone rubber at a mass ratio of 50:50 (calculated per 100 parts). 50 parts of hydrophobic silica (TS530) were added, followed by 2 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy) and 2 parts of an amino-containing organic compound, and the mixing was continued. The mixture was then cured at 170°C for 4 hours, heat-treated at 200°C for 1 hour, and heat-treated at 230°C for 4 hours to obtain modified silicone rubber samples A to J. The structural formulas after vulcanization are shown as follows:

[0046]

[0047] Comparative example group: 100 parts of methyl vinyl silicone rubber, designated as the control sample.

[0048] The main raw material components of modified silicone rubber samples A to J and control sample 1 are shown in Table 1 (by weight parts).

[0049] Table 1

[0050]

[0051] Modified silicone rubber samples A-J and control sample 1 were immersed in a solvent at 30℃ for 30 days, and the rate of mass change was tested. The test results are shown in Table 2.

[0052] The tensile strength of modified silicone rubber samples A-J and control sample 1 was tested at 280℃. The test results are shown in Table 2.

[0053] Table 2

[0054]

[0055]

[0056] As can be seen from Table 2, the addition of the aforementioned nitrile-containing fluorinated polysiloxane to silicone rubber significantly improves its polar solvent resistance and heat resistance.

Claims

1. A modified polysiloxane raw material composition, wherein, Including fluorinated polysiloxanes and nitrile-containing olefin compounds; The structure of the fluorinated polysiloxane is R. f -bR;R f R represents a perfluoropolyether segment, R represents a polysiloxane segment, and b represents a block; The nitrile-containing olefin compound is selected from one or more combinations of acrylonitrile, allyl nitrile, cyclohexenyl acetonitrile and 5-hexenonitrile.

2. The modified polysiloxane raw material composition according to claim 1, wherein, The molar ratio of the nitrile-containing olefin compound to the fluorinated polysiloxane is 2 to 10:

1.

3. The modified polysiloxane raw material composition according to claim 1, wherein, It also includes fluorocarbon solvents; The fluorocarbon solvent is selected from one or more combinations of nonafluorobutyl ethyl ether, nonafluorobutyl methyl ether, trifluorotoluene, 1,3-bis(trifluoromethyl)benzene, perfluorocyclic ethers and perfluorohexane.

4. The modified polysiloxane raw material composition according to claim 1, wherein, It also includes catalysts; The catalyst is selected from one or more of the following: Castells catalyst, Speier catalyst, benzoyl peroxide, di-tert-butyl peroxide, and platinum catalyst. The amount of the catalyst is 0.01 to 10 wt% of the weight of the modified polysiloxane raw material composition.

5. The modified polysiloxane raw material composition according to claim 1, wherein, It also includes organic alcohol compounds.

6. The modified polysiloxane raw material composition according to claim 5, wherein, The organic alcohol compound is selected from one or more combinations of methanol, ethanol, isopropanol, tert-butanol, ethylene glycol, polyethylene glycol, and propylene glycol.

7. The modified polysiloxane raw material composition according to claim 1, wherein, In the fluorinated polysiloxane, the raw material source of the perfluoropolyether segment includes one or more combinations of K-type perfluoropolyether, D-type perfluoropolyether, Y-type perfluoropolyether, and Z-type perfluoropolyether; and / or, In the fluorinated polysiloxane, the raw material source of the polysiloxane chain segment includes one or more combinations of terminal silane-hydrogen polysiloxane, side silane-hydrogen polysiloxane, and terminal mercapto polysiloxane.

8. A method for preparing a nitrile-containing fluorinated polysiloxane, wherein, The modified polysiloxane raw material composition according to any one of claims 1 to 7 is used in the preparation method comprising: mixing a fluorinated polysiloxane and a nitrile olefin compound to carry out a chemical reaction to obtain a product system, and separating the nitrile fluorinated polysiloxane from the product system.

9. The method for preparing nitrile-containing fluorinated polysiloxanes according to claim 8, wherein, Includes the following steps: The chemical reaction is carried out by mixing the fluorinated polysiloxane, the nitrile-containing olefin compound, the fluorocarbon solvent and the catalyst to obtain the product system. An organic alcohol compound is added to the product system, and then the product system is allowed to separate and stand. The lower layer is taken out and distilled to obtain the nitrile-containing fluorinated polysiloxane.

10. The method for preparing nitrile-containing fluorinated polysiloxanes according to claim 8, wherein, The chemical reaction between the fluorinated polysiloxane and the nitrile-containing olefin compound is carried out at a temperature of 25–170°C for a time of 1–72 h.

11. A fluorinated polysiloxane containing a nitrile group, wherein, It is prepared by the preparation method described in claim 8 or 9.

12. A modified silicone composition, wherein, Includes the nitrile-containing fluorinated polysiloxane and silicone rubber as described in claim 11.

13. The modified silicone composition according to claim 12, wherein, It also includes amino-containing organic compounds, crosslinking agents, and auxiliaries; The amino-containing organic compound is selected from one or more combinations of 4,4'-diaminodiphenyl sulfone, aminopropyltriethoxysilane, and amino silicone oil.

Images