Metal organic silicon heat-resistant resin, preparation method thereof and application of metal organic silicon heat-resistant resin in silicone rubber

Abstract

The invention belongs to the technical field of composite material preparation, and particularly relates to metal organic silicon heat-resistant resin, a preparation method thereof and application of the metal organic silicon heat-resistant resin in silicone rubber. Comprising the following steps: (1) adding diphenyl (3-(triethoxysilyl) propyl) phosphine and methyltriethoxysilane into ethanol, and heating to obtain a mixed solution; and (2) dropwise adding an aqueous solution containing ceric ammonium nitrate, phosphoric acid and (2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester into the mixed solution obtained in the step (1), reacting, and removing low-pressure to obtain the product. The silicon resin which is doped with high-valence cerium ions and contains a phenyl structure and a phosphorus element is used as a heat-resistant agent of the silicon rubber, so that the compatibility with the silicon rubber is improved, the dispersity is enhanced, and the heat resistance is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and specifically relates to a metal-organic silicon heat-resistant resin, its preparation method, and its application in silicone rubber. Background Art

[0002] Due to its excellent weather resistance, ultraviolet resistance, biocompatibility and other advantages, silicone rubber is widely used in aerospace, 5G, high-speed rail, construction and other fields. With the rapid development of modern industry, the demand for high-temperature resistant silicone rubber products is increasing. Methyl silicone rubber can usually withstand a temperature of 260 °C, but under long-term use conditions, it will cause thermal oxidation aging of the silicone rubber, making it lose elasticity, embrittle and powder. With the improvement of technology level, higher performance requirements are put forward for silicone rubber products used in extreme environments. Especially with the rapid development of new energy, silicone rubber products that can be used at high temperatures have attracted much attention.

[0003] Chinese Patent Application Publication No. C117402497A reports a long-term high-temperature resistant silicone rubber prepared by adding diphenylsilanediol and nano high-temperature resistant agents (a mixture of nano-aluminum oxide, nano-iron oxide and nano-cerium oxide), which can be effectively used for about 30 days at high temperatures of 300 °C to 350 °C, and can be widely used in nuclear cables, aerospace cables and other fields. Chinese Patent Application Publication No. CN119432078A reports a high-temperature resistant silicone rubber composition prepared by adding a modified nano-inorganic heat-resistant additive (one or more of titanium oxide, cerium oxide, cerium hydroxide, iron oxide, calcium carbonate, silica powder). Chinese Patent Application Publication No. CN116218227A reports a high-temperature resistant silicone rubber filled with an inorganic heat-resistant agent containing iron and tin (FS). Therefore, the most commonly used method to improve the temperature resistance of silicone rubber at present is to add inorganic heat-resistant agents. In order to increase the compatibility with silicone rubber and achieve good processability, the heat-resistant agents need to be further modified with silane coupling agents.

[0004] However, at present, designing new structures to strengthen the compatibility between additives and silicone rubber and obtaining high-temperature resistant silicone rubber still faces great challenges. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a metal-organic silicon heat-resistant resin, its preparation method, and its application in silicone rubber. Using a silicon resin doped with high-valent cerium ions and containing phenyl structures and phosphorus elements as a heat-resistant agent for silicone rubber not only improves the compatibility with silicone rubber, enhances the dispersibility, but also further improves the heat resistance.

[0006] The preparation method of the metal-organic silicon heat-resistant resin described in the present invention includes the following steps:

[0007] (1) Add diphenyl(3-(triethoxysilyl)propyl)phosphine and methyltriethoxysilane to ethanol, heat up to obtain a mixed solution;

[0008] (2) Dropwise add an aqueous solution containing ammonium cerium nitrate, phosphoric acid, and (2-ethylhexyl)phosphoric acid mono-2-ethylhexyl ester into the mixed solution obtained in step (1), and then perform vacuum distillation to remove low-boiling components to obtain the product.

[0009] Preferably, in step (1), the mass ratio of diphenyl(3-(triethoxysilyl)propyl)phosphine to methyltriethoxysilane is 1:(0.10 - 0.45).

[0010] Preferably, the mass ratio of the total mass of diphenyl(3-(triethoxysilyl)propyl)phosphine and methyltriethoxysilane to ethanol is (50 - 200):1000.

[0011] Preferably, in step (1), heat up to 40 - 80 °C.

[0012] Preferably, in step (2), the mass ratio of ammonium cerium nitrate, phosphoric acid, (2-ethylhexyl)phosphoric acid mono-2-ethylhexyl ester to water is (0.05 - 0.1):(0.01 - 0.05):(0.05 - 0.1):1.

[0013] Preferably, in step (1), the mass ratio of ethanol to water in the aqueous solution in step (2) is 1:(1 - 3).

[0014] Preferably, in step (2), the reaction time is 4 - 10 h, and the reaction temperature is 40 - 80 °C.

[0015] The organosilicon heat-resistant resin of the present invention is prepared by the above preparation method.

[0016] The application of the organosilicon heat-resistant resin of the present invention as a heat-resistant agent in silicone rubber.

[0017] The mechanism of the present invention is as follows:

[0018] For the organosilicon heat-resistant resin of the present invention, methyltriethoxysilane and diphenyl(3-(triethoxysilyl)propyl)phosphine are mixed, and an acidic aqueous solution containing phosphoric acid and (2-ethylhexyl)phosphoric acid mono-2-ethylhexyl ester is used to promote the hydrolysis and polycondensation of alkoxysilane in the ethanol / water system. The P-OH group of (2-ethylhexyl)phosphoric acid mono-2-ethylhexyl ester forms a coordination with the silanol group, and the phosphate ester is embedded in the silicone resin. To further improve the heat resistance, high-valent cerium ions are coordinated with phenylphosphorus groups and P=O groups with strong coordination functions, and the metal ions are evenly embedded in the structure. The formed cerium metal ion-doped phosphate ester phenyl silicone resin has excellent heat resistance.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The reaction conditions of the preparation method of the present invention are mild, the reaction equipment is simple, and the cost and operation difficulty are reduced;

[0021] 2. The metal-organic silicon heat-resistant resin of the present invention has excellent performance, good compatibility with silicone rubber, and significantly improves the heat resistance performance;

[0022] 3. The process is simple, without high temperature and high pressure or special devices, and is suitable for industrial production. Description of the Drawings

[0023] Figure 1 Infrared spectrum of the metal-organic silicon heat-resistant resin in Example 1;

[0024] Figure 2 Comparison chart of pure silicone rubber and silicone rubber in Example 1 (a is pure silicone rubber, b is silicone rubber in Example 1);

[0025] Figure 3 Thermogravimetric diagram of pure silicone rubber and silicone rubber in Example 1 (A is pure silicone rubber, B is silicone rubber in Example 1). Detailed Embodiments

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and embodiments.

[0027] All raw materials used in the embodiments are commercially available unless otherwise specified.

[0028] Example 1

[0029] The preparation method of the metal-organic silicon heat-resistant resin includes the following steps:

[0030] (1) Add 10 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 2 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 60 °C to obtain a mixed solution;

[0031] (2) Dissolve 11.25 g of ammonium cerium nitrate, 3 g of phosphoric acid, and 8 g of bis(2-ethylhexyl) phosphate in 150 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1), react at 60 °C for 7 h, and then perform vacuum distillation to remove ethanol and water to obtain the product.

[0032] Example 2

[0033] The preparation method of the metal-organic silicon heat-resistant resin includes the following steps:

[0034] (1) Add 5 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 0.5 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 80 °C to obtain a mixed solution;

[0035] (2) Dissolve 5 g of ammonium cerium(IV) nitrate, 1 g of phosphoric acid, and 5 g of bis(2-ethylhexyl) phosphate in 100 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1), and react at 80 °C for 4 h. Then, remove ethanol and water under reduced pressure to obtain the product.

[0036] Example 3

[0037] The preparation method of the metal-organic silicon heat-resistant resin comprises the following steps:

[0038] (1) Add 13 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 5.85 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 40 °C to obtain a mixed solution;

[0039] (2) Dissolve 30 g of ammonium cerium(IV) nitrate, 15 g of phosphoric acid, and 30 g of bis(2-ethylhexyl) phosphate in 300 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1), and react at 40 °C for 10 h. Then, remove ethanol and water under reduced pressure to obtain the product.

[0040] Example 4

[0041] The preparation method of the metal-organic silicon heat-resistant resin comprises the following steps:

[0042] (1) Add 10 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 4.5 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 40 °C to obtain a mixed solution;

[0043] (2) Dissolve 10 g of ammonium cerium(IV) nitrate, 8 g of phosphoric acid, and 15 g of bis(2-ethylhexyl) phosphate in 200 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1), and react at 40 °C for 10 h. Then, remove ethanol and water under reduced pressure to obtain the product.

[0044] Example 5

[0045] The preparation method of the metal-organic silicon heat-resistant resin comprises the following steps:

[0046] (1) Add 10 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 1 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 40 °C to obtain a mixed solution;

[0047] (2) Dissolve 5 g of ammonium cerium nitrate, 1 g of phosphoric acid, and 5 g of bis(2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester in 100 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1). After reacting at 50 °C for 8 h, remove ethanol and water under reduced pressure to obtain the product.

[0048] Example 6

[0049] The preparation method of the metal-organic silicon heat-resistant resin described above includes the following steps:

[0050] (1) Add 10 g of diphenyl(3-(triethoxysilyl)propyl)phosphine and 3 g of methyltriethoxysilane to 100 g of ethanol, and heat up to 40 °C to obtain a mixed solution;

[0051] (2) Dissolve 15 g of ammonium cerium nitrate, 1.5 g of phosphoric acid, and 15 g of bis(2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester in 150 g of water to obtain an aqueous solution. Drop the aqueous solution into the mixed solution obtained in step (1). After reacting at 60 °C for 8 h, remove ethanol and water under reduced pressure to obtain the product.

[0052] Comparative Example 1

[0053] The difference between this Comparative Example 1 and Example 1 is that in step (1), methyltriethoxysilane is used to replace diphenyl(3-(triethoxysilyl)propyl)phosphine in equal mass.

[0054] Comparative Example 2

[0055] The difference between this Comparative Example 2 and Example 1 is that in the preparation of the aqueous solution in step (2), ammonium cerium nitrate is not added, and the mass of bis(2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester added is 12 g.

[0056] Comparative Example 3

[0057] The difference between this Comparative Example 3 and Example 1 is that in the preparation of the aqueous solution in step (2), bis(2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester is replaced with ammonium cerium nitrate in equal mass.

[0058] Comparative Example 4

[0059] The difference between this Comparative Example 4 and Example 1 is that in the preparation of the aqueous solution in step (2), phosphoric acid is replaced with ammonium cerium nitrate in equal mass.

[0060] Comparative Example 5

[0061] The difference between this Comparative Example 5 and Example 1 is that in step (1), methyltriethoxysilane is replaced with diphenyl(3-(triethoxysilyl)propyl)phosphine in equal mass.

[0062] Performance Test

[0063] Take 10 g each of the heat-resistant resins obtained in Examples 1-6 and Comparative Examples 1-5, and mix them evenly with 100 g of hydroxyl-terminated polysiloxane (viscosity 10,000 mPa·s), 6 g of methyl orthosilicate, and 3 g of organotin. After vacuum degassing, cure to obtain silicone rubber. Characterize the thermal gravimetric properties of the silicone rubbers obtained in Examples 1-6, Comparative Examples 1-5, and pure silicone rubber. The test conditions are 100-800 °C, and the heating rate is 10 °C / min. Evaluate the heat resistance of the products through thermogravimetric analysis. The results are shown in Table 1.

[0064] The above pure silicone rubber is obtained by mixing 100 g of hydroxyl-terminated polysiloxane (viscosity 10,000 mPa·s), 6 g of methyl orthosilicate, and 3 g of organotin evenly and then curing after vacuum degassing.

[0065] Table 1 Thermal weight loss data of silicone rubbers in Examples 1-6, pure silicone rubber, and Comparative Examples 1-5

[0066]

[0067] From Table 1 combined with Figure 3 It can be seen that the silicone rubber containing the organosilicon heat-resistant resin of the present invention has a thermal weight loss of 8% at 380 °C, while the pure silicone rubber has a thermal weight loss of 17% at 380 °C. This proves that after adding the organosilicon heat-resistant resin obtained in Example 1, the thermal decomposition temperature and heat resistance of the obtained silicone rubber are significantly improved. Combined with Figure 2 It is proved that the organosilicon heat-resistant resin is well dispersed in the silicone rubber, and the contact area between the two is greatly increased, effectively improving its heat resistance. The data in Table 1 show that compared with pure silicone rubber, the thermal weight loss rate of the silicone rubber in Examples 1-6 decreased significantly by 41%-53% after adding the heat-resistant resin of the present invention, indicating that the heat-resistant resin of the present invention can significantly improve the thermal aging performance of silicone rubber in high-temperature environments. By comparing the examples with the comparative examples, it can be seen that the products prepared without completely using the raw materials of the present invention cannot effectively help improve the heat resistance of silicone rubber.

[0068] From Figure 1 the infrared spectrum of the organosilicon heat-resistant resin in Example 1, it can be seen that the peak at 1610 cm -1 is the characteristic peak of the benzene ring, coming from diphenyl(3-(triethoxysilyl)propyl)phosphine. The characteristic peak at 1010 cm -1 is the silicon-oxygen characteristic peak, indicating the presence of oligomers of organosilicon in the product. The characteristic peak in the range of 3400 cm -1 is the amino group, coming from ammonium cerium nitrate. The peak at 2330 cm -1 is the phosphorus-oxygen characteristic peak, coming from mono-2-ethylhexyl (2-ethylhexyl) phosphate. The peak at 2870 cm -1is the characteristic peak of methyl group, coming from methyltriethoxysilane. 980 cm -1 is the characteristic peak of phosphate group, coming from the added phosphate group.

Claims

1. A preparation method of a metal-organic silicon heat-resistant resin, characterized in that, It includes the following steps: (1) Add diphenyl(3-(triethoxysilyl)propyl)phosphine and methyltriethoxysilane into ethanol, heat up to obtain a mixed solution; (2) Dropwise add an aqueous solution containing ammonium cerium nitrate, phosphoric acid, and mono-2-ethylhexyl (2-ethylhexyl) phosphate into the mixed solution obtained in step (1), and obtain the product after reaction by reducing pressure to remove low-boiling components.

2. The preparation method of the organosilicon heat-resistant resin according to claim 1, characterized in that, In step (1), the mass ratio of diphenyl(3-(triethoxysilyl)propyl)phosphine to methyltriethoxysilane is 1:(0.10 - 0.45).

3. The preparation method of the organosilicon heat-resistant resin according to claim 1, characterized in that, The mass ratio of the total mass of diphenyl(3-(triethoxysilyl)propyl)phosphine and methyltriethoxysilane to the mass of ethanol is (50 - 200):1000.

4. The preparation method of the metal-organic silicon heat-resistant resin according to claim 1, characterized in that, In step (1), heat up to 40 - 80 °C.

5. The preparation method of the organosilicon heat-resistant resin according to claim 1, characterized in that, In step (2), the mass ratio of ammonium cerium nitrate, phosphoric acid, mono-2-ethylhexyl (2-ethylhexyl) phosphate to water is (0.05 - 0.1):(0.01 - 0.05):(0.05 - 0.1):

1.

6. The preparation method of the organosilicon metal heat-resistant resin according to claim 1, characterized in that, In step (1), the mass ratio of ethanol to water in the aqueous solution in step (2) is 1:(1 - 3).

7. The preparation method of the organosilicon heat-resistant resin according to claim 1, characterized in that, In step (2), the reaction time is 4 - 10 h, and the reaction temperature is 40 - 80 °C.

8. A metal-organic silicon heat-resistant resin, characterized in that, Obtained by the preparation method according to claims 1 - 7.

9. Application of the organosilicon metal heat-resistant resin according to claim 8 as a heat-resistant agent in silicone rubber.

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