Fluorosilicone raw rubber as well as preparation method and application thereof

Abstract

The invention relates to the technical field of silicone rubber, and discloses fluorosilicone raw rubber, a preparation method and application thereof, and the fluorosilicone raw rubber comprises the following raw materials by weight: 50-99 parts of D3F; 0.01 to 10 parts of D4vi (D4Vi); 0.01 to 10 parts of a potassium silanolate catalyst prepolymer; 0.01 to 10 parts of a neutralizing agent; wherein the potassium silanolate catalyst prepolymer is prepared from the following raw materials in parts by weight: 0.1 to 3 parts of potassium alkali; 90 to 100 parts of D4; and 0.001 to 2 parts of an end-capping reagent. The fluorosilicone raw rubber has excellent high and low temperature resistance and mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of silicone rubber technology, and in particular to a fluorosilicone raw rubber, its preparation method, and its application. Background Technology

[0002] Fluorosilicone raw rubber, as a base material of silicone rubber modified with fluorine groups, has been widely used in key fields such as aerospace, automotive, and petrochemical industries due to its unique advantages of combining the high-temperature resistance and weather resistance of silicone rubber with the oil and solvent resistance of fluorinated materials. Since fluorosilicone raw rubber often needs to be exposed to harsh environments for extended periods, current technologies mostly employ the addition of temperature-resistant agents to improve its temperature resistance. However, the introduction of such additives can adversely affect the basic properties of the rubber compound, such as hardness and elasticity. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a fluorosilicone raw rubber, its preparation method, and its application. This fluorosilicone raw rubber possesses both excellent high and low temperature resistance and mechanical strength.

[0004] The first specific technical solution of the present invention is: a fluorosilicone raw rubber, comprising the following raw materials by weight: D3F: 50-99 servings; D4 vi 0.01-10 portions; Potassium silanolate catalyst prepolymer: 0.01-10 parts; Neutralizing agent: 0.01-10 parts; The potassium silanolate catalyst prepolymer, by weight, includes the following raw materials: Potassium alkali: 0.1-3 parts; D4: 90-100 servings; End-capping agent: 0.001-2 parts.

[0005] In the aforementioned fluorosilicone raw rubber, the trifluoropropyl group of the core monomer D3F forms a robust high- and low-temperature resistant framework with high-bond-energy CF bonds, thus improving component compatibility. D4 vi Vinyl crosslinking sites are introduced into the main chain formed by D3F, providing reaction sites for subsequent crosslinking. This is achieved by regulating the interaction between D3F and D4. vi The mixing ratio can directly control the vinyl concentration in the rubber compound, giving the finished product both higher mechanical strength and good elasticity; D4 viIt can also regulate molecular chain length and crosslinking density, balancing flexibility and mechanical strength. The low-ratio design avoids excessive crosslinking leading to a decrease in temperature resistance. The potassium silanolate catalyst prepolymer has good compatibility with the fluorosilicone system and can be uniformly dispersed in the raw materials, avoiding performance defects caused by uneven local reactions. Simultaneously, its catalytic products are easily removed through subsequent neutralization steps, minimizing residual impurities that could affect the purity of the raw rubber. The neutralizing agent eliminates residual acidic groups, preventing thermal degradation. Furthermore, D3F is cheaper than D4. vi A high D3F ratio can reduce raw material costs without significantly sacrificing performance while meeting basic crosslinking requirements. This invention achieves simultaneous optimization of high and low temperature resistance and mechanical strength through specific raw material ratios and synergistic effects of components, while also controlling costs.

[0006] Preferably, a fluorosilicone raw rubber comprises, by weight, the following raw materials: D3F: 50-99 servings; D4 vi 0.1-10 portions; Potassium silanolate catalyst prepolymer: 1-10 parts; Neutralizing agent: 1-10 parts; The potassium silanolate catalyst prepolymer, by weight, includes the following raw materials: Potassium alkali: 0.5-1 part; D4: 90-100 servings; Capping agent: 0.1-2 parts.

[0007] Optionally, the potassium base is KOH, the capping agent is tetramethyldivinyldisiloxane, and the neutralizing agent is acetic acid.

[0008] In the above technical solution, tetramethyldivinyldisiloxane can, on the one hand, adjust the solubility of the prepolymer to make it compatible with fluorosilicone monomers such as D3F, ensuring uniform polymerization reaction; on the other hand, because its molecular structure contains two vinyl groups, it will stably graft onto the siloxane chain of the prepolymer, subsequently participate in the D3F polymerization along with the prepolymer, and ultimately remain in the fluorosilicone raw rubber, providing sufficient crosslinking sites for subsequent vulcanization to prepare rubber, thereby improving the tear strength and tensile strength of the rubber; at the same time, tetramethyldivinyldisiloxane can form stable chemical bonds with the active groups of the polymer chain, directly improving the mechanical properties, heat resistance, and chemical corrosion resistance of the material; in addition, its low surface energy characteristics can achieve surface modification of the material, giving the fluorosilicone raw rubber excellent hydrophobicity and anti-friction properties, adapting to the application requirements of harsh environments; in the processing stage, it can also reduce the viscosity of the system and improve the fluidity, balancing processing efficiency and cost control. Acetic acid can eliminate residual alkaline groups in the alkali metal silanolate potassium silanolate catalyst prepolymer through acid-base neutralization reaction, preventing residual groups from causing thermal degradation of the siloxane chain and ensuring the thermal stability of the raw rubber. At the same time, acetic acid has both weak acid and solvent properties, which can inhibit the growth of microorganisms during storage, playing a role in preservation, and can also promote the uniform dispersion of each component, improving the stability of the system. In addition, acetic acid will not undergo side reactions with the fluorosilicone raw rubber backbone, ensuring that the neutralization process does not damage the molecular structure and properties of the raw rubber.

[0009] The second specific technical solution of the present invention is: a method for preparing fluorosilicone raw rubber, comprising the following steps: (1) First, put D3F and D4 vi The mixture was dehydrated under vacuum, and then potassium silanolate catalyst prepolymer was added. The mixture was heated under an inert gas atmosphere to carry out a polymerization reaction to obtain an intermediate product. (2) Mix the intermediate product with a neutralizing agent and dehydrate under vacuum to obtain fluorosilicone raw rubber.

[0010] In the above preparation method, D3F and D4 are first prepared. vi The mixture is pretreated by vacuum dehydration to avoid non-specific hydrolysis of D3F. The dehydrated mixture is then subjected to polymerization under alkaline catalysis to produce fluorosilicone polymer. After the polymerization reaction is completed, a neutralizing agent is added to neutralize the residual alkaline groups. The neutralization reaction will generate water or salt impurities. Vacuum dehydration can remove these impurities and ensure the purity of the fluorosilicone raw rubber.

[0011] Optionally, in step (1), the vacuum dehydration specifically involves vacuum dehydration at 40-70°C for 4-5 hours; the reaction temperature of the polymerization reaction is 60-120°C, and the reaction time is 0.1-7 hours.

[0012] Optionally, in step (2), the intermediate product is cooled to 10-30°C and then mixed with the neutralizing agent; the vacuum dehydration specifically involves vacuum dehydration at 130-160°C for 2-3 hours.

[0013] Optionally, in step (1), the preparation process of the potassium silanolate catalyst prepolymer is as follows: first, the mixture of potassium alkali, D4 and end-capping agent is dehydrated under vacuum, and then heated and stirred under an inert gas atmosphere to generate the potassium silanolate catalyst prepolymer.

[0014] Optionally, the product can be vacuum dehydrated at 40-70℃ for 2-3 hours, and then heated to 60-90℃ in an inert gas atmosphere.

[0015] The third specific technical solution of the present invention is: an application of fluorosilicone raw rubber in the preparation of compound rubber, wherein the compound rubber comprises the following raw materials by weight: Fluorosilicone raw rubber: 90-110 parts; Silica: 10-50 parts; Hydroxyfluorosilicone oil: 1-10 parts; Zinc stearate: 0.01-1 part; Among them, the fluorosilicone raw rubber is the aforementioned fluorosilicone raw rubber.

[0016] Preferably, the compound comprises the following raw materials: Fluorosilicone raw rubber: 90-100 parts; Silica: 10-50 parts; Hydroxyfluorosilicone oil: 3-10 parts; Zinc stearate: 0.1-0.16 parts.

[0017] Compared with the prior art, the present invention has at least the following advantages: by controlling D3F and D4 vi The mixing ratio of D4 can directly control the vinyl concentration in the rubber compound, giving the finished product both higher mechanical strength and good elasticity; vi By controlling the molecular chain length and crosslinking density, a balance can be struck between flexibility and mechanical strength, while a low-ratio design can prevent the decrease in temperature resistance caused by excessive crosslinking. Furthermore, D3F is cheaper than D4. vi The high D3F ratio can reduce raw material costs without significantly sacrificing performance while meeting basic crosslinking requirements; the potassium silanolate catalyst prepolymer has good compatibility with the fluorosilicone system and can be uniformly dispersed in the raw materials, avoiding performance defects caused by uneven local reactions; at the same time, its catalytic products are easy to remove through subsequent neutralization steps, and it is not easy for residual impurities to affect the purity of raw rubber. Detailed Implementation

[0018] The present invention will now be described through specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Variations and advantages that can be conceived by those skilled in the art without departing from the spirit and scope of the inventive concept are included in the present invention, and the scope of protection of the present invention is defined by the appended claims and any equivalents thereof.

[0019] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Unless otherwise specified, the raw materials and equipment used in this invention are conventional in the art and can be obtained through conventional commercial means; unless otherwise specified, the methods used in this invention are conventional methods in the art.

[0020] The following embodiments are merely illustrative examples of the target range of raw material proportions in the technical solution of the present invention, and are not intended to limit the scope of protection of the present invention. In actual production applications, the weight proportions of the raw material components can be varied according to requirements to obtain different hardness, tear strength, low temperature resistance, mechanical strength, etc.

[0021] Example 1: This invention provides a fluorosilicone raw rubber, comprising the following raw materials by weight: D3F (trifluoropropylmethylcyclotrisiloxane): 70 parts; D4 vi (Tetramethyltetravinylcyclotetrasiloxane): 0.5 parts; Potassium silanolate catalyst prepolymer: 5 parts; Neutralizing agent: 5 parts.

[0022] The potassium silanolate catalyst prepolymer, by weight, includes the following raw materials: Potassium alkali: 1 part; D4 (octamethylcyclotetrasiloxane): 100 parts; Capping agent: 0.55 parts.

[0023] Tetramethyldivinyldisiloxane was used as the capping agent, KOH as the potassium base, and acetic acid as the neutralizing agent.

[0024] Example 2: This invention provides a fluorosilicone raw rubber, which differs from Example 1 in that, by weight, it comprises the following raw materials: D3F: 50 servings; D4 vi 0.1 copies; Potassium silanolate catalyst prepolymer: 1 part; Neutralizing agent: 1 part.

[0025] The potassium silanolate catalyst prepolymer, by weight, includes the following raw materials: Potassium alkali: 1 part; D4: 90 servings; Capping agent: 0.1 parts.

[0026] Example 3: This invention provides a fluorosilicone raw rubber, which differs from Example 1 in that, by weight, it comprises the following raw materials: D3F: 99 servings; D4 vi 10 copies; Potassium silanolate catalyst prepolymer: 10 parts; Neutralizing agent: 10 parts.

[0027] The potassium silanolate catalyst prepolymer, by weight, includes the following raw materials: Potassium alkali: 0.5 parts; D4: 100 servings; End-capping agent: 2 parts.

[0028] Example 4: This invention provides a method for preparing fluorosilicone raw rubber, based on the fluorosilicone raw rubber raw material formulation of Example 1, including the following steps: (1) First, place D3F and D4 vi Add to a double planetary mixer and mix, combining D3F and D4. vi The mixture is heated to 60°C and vacuum dehydrated for 4 hours. During vacuum dehydration, the pressure gauge is checked to see if the machine is leaking. The pressure gauge should reach 0.1 MPa. After dehydration, potassium silanol catalyst prepolymer is added, the temperature is raised to 80°C, N2 is introduced and stirred to carry out the polymerization reaction. During the polymerization reaction, the stirring is fast at the beginning, and the viscosity of the material in the reactor is observed. When the viscosity becomes obviously thickened, the stirring speed is reduced. The polymerization reaction is carried out for 7 hours. After the reaction is completed, the intermediate product is obtained. (2) The intermediate product is still placed in the double planetary mixer. After the double planetary mixer is cooled to 20°C, acetic acid is added and stirred for 2 hours to neutralize. Then the temperature is raised to 150°C and vacuum dehydrated for 2 hours to obtain fluorosilicone raw rubber. During vacuum dehydration, check the pressure gauge to see if the machine is leaking. The pressure gauge should reach 0.1 MPa.

[0029] In step (1), the preparation process of potassium silanolate catalyst prepolymer is as follows: KOH, D4 and tetramethyldivinyldisiloxane are added to the reactor in proportion, stirred and mixed, heated to 60°C and vacuum dehydrated for 2 hours. Small bubbles will appear in the solution during vacuum dehydration. Check the pressure gauge. The pressure gauge should show 0.1 MPa. After dehydration, the temperature is raised to 80°C and N2 is introduced for stirring and reaction for 2 hours. During the reaction, small water droplets appear at the gas outlet of the reactor and there is a slight gas venting sound. After the reaction, potassium silanolate catalyst prepolymer is obtained.

[0030] It should be noted that, by default, the temperature of the equipment and the temperature of the materials therein are kept consistent in this invention.

[0031] Example 5: This invention provides a method for preparing fluorosilicone raw rubber, based on the fluorosilicone raw rubber raw material formulation of Example 2, including the following steps: (1) First, place D3F and D4 vi Add to a double planetary mixer and mix, combining D3F and D4. vi The mixture is heated to 60°C and vacuum dehydrated for 5 hours. During vacuum dehydration, the pressure gauge is checked to see if the machine is leaking. The pressure gauge should reach 0.1 MPa. After dehydration, potassium silanol catalyst prepolymer is added, the temperature is raised to 85°C, N2 is introduced and stirred to carry out the polymerization reaction. During the polymerization reaction, the stirring is fast at the beginning, and the viscosity of the material in the reactor is observed. When the viscosity becomes obviously thickened, the stirring speed is reduced. The polymerization reaction is carried out for 5 hours. After the reaction is completed, the intermediate product is obtained. (2) The intermediate product is still placed in the double planetary mixer. After the double planetary mixer is cooled to 10°C, acetic acid is added and stirred for 2 hours to neutralize. Then the temperature is raised to 130°C and vacuum dehydrated for 2 hours to obtain fluorosilicone raw rubber. During vacuum dehydration, check the pressure gauge to see if the machine is leaking. The pressure gauge should reach 0.1 MPa.

[0032] In step (1), the preparation process of potassium silanolate catalyst prepolymer is as follows: KOH, D4 and tetramethyldivinyldisiloxane are added to the reactor in proportion, stirred and mixed, heated to 60°C and vacuum dehydrated for 3 hours. Small bubbles will appear in the solution during vacuum dehydration. Check the pressure gauge. The pressure gauge should show 0.1 MPa. After dehydration, the temperature is raised to 85°C and N2 is introduced for stirring and reaction for 2 hours. During the reaction, small water droplets appear at the gas outlet of the reactor and there is a slight gas venting sound. After the reaction, potassium silanolate catalyst prepolymer is obtained.

[0033] Example 6: This invention provides a method for preparing fluorosilicone raw rubber, based on the fluorosilicone raw rubber raw material formulation of Example 3, including the following steps: (1) First, place D3F and D4 vi Add to a double planetary mixer and mix, combining D3F and D4. vi The mixture is heated to 70℃ and vacuum dehydrated for 5 hours. During vacuum dehydration, the pressure gauge is checked to see if the machine is leaking. The pressure gauge should reach 0.1 MPa. After dehydration, potassium silanol catalyst prepolymer is added, the temperature is raised to 100℃, N2 is introduced and stirred to carry out the polymerization reaction. During the polymerization reaction, the stirring is fast at the beginning, and the viscosity of the material in the reactor is observed. When the viscosity becomes obviously thickened, the stirring speed is reduced. The polymerization reaction is carried out for 1 hour. The intermediate product is obtained after the reaction is completed. (2) The intermediate product is still placed in the double planetary mixer. After the double planetary mixer is cooled to 30°C, acetic acid is added and stirred for 2 hours to neutralize. Then the temperature is raised to 160°C and vacuum dehydrated for 2 hours to obtain fluorosilicone raw rubber. During vacuum dehydration, check the pressure gauge to see if the machine is leaking. The pressure gauge should reach 0.1 MPa.

[0034] In step (1), the preparation process of potassium silanolate catalyst prepolymer is as follows: KOH, D4 and tetramethyldivinyldisiloxane are added to the reactor in proportion, stirred and mixed, heated to 70°C and vacuum dehydrated for 2 hours. Small bubbles will appear in the solution during vacuum dehydration. Check the pressure gauge. The pressure gauge should show 0.1 MPa. After dehydration, the temperature is raised to 90°C and N2 is introduced for stirring and reaction for 3 hours. During the reaction, small water droplets appear at the gas outlet of the reactor and there is a slight gas venting sound. After the reaction, potassium silanolate catalyst prepolymer is obtained.

[0035] Example 7: This invention provides an application of fluorosilicone raw rubber in the preparation of compound rubber. Based on the fluorosilicone raw rubber obtained in Example 4, the compound rubber comprises the following raw materials by weight: Fluorosilicone raw rubber: 100 parts; Silica: 50 parts; Hydroxyfluorosilicone oil: 10 parts; Zinc stearate: 0.16 parts.

[0036] The weight proportions of the above components can be varied according to requirements to obtain different hardness, tear strength, low-temperature resistance, mechanical strength, etc. For example, in another embodiment, based on the fluorosilicone raw rubber prepared in Example 4, the compound comprises the following raw materials by weight proportions: Fluorosilicone raw rubber: 90 parts; Silica: 10 parts; Hydroxyfluorosilicone oil: 3 parts; Zinc stearate: 0.1 parts.

[0037] The preparation method of the above-mentioned compound is as follows: add fluoro-based raw rubber and zinc stearate into a kneader, then add phenyl silicone oil, hydroxyl fluorosilicone oil and fumed silica in sequence (fumed silica is added in batches), after kneading is completed, let stand for 24 hours, and then perform vacuum treatment on the compound to obtain the compound.

[0038] The mechanical strength of the compound prepared in Example 7 was tested at high temperature. The testing standards are as follows: high temperature resistance test refers to GB / T 1690-2010; hardness test refers to GB / T 531.1; tensile strength test refers to GB / T 528; elongation test refers to GB / T 528; maximum force test refers to GB / T 529.

[0039] The testing process is as follows: Take 50g of compound rubber and add 1g of bis(tert-butylperoxyisopropyl)benzene (vulcanizing agent). Mix the two evenly with a rubber mixing machine, and then make standard test pieces. Place the test pieces in a high-temperature aging chamber and age them in a dry environment at 160℃ for 1 hour. After aging, close the aging chamber and allow it to cool naturally to 23℃. Refer to the mechanical strength test standard to test the hardness, tensile strength, elongation at break, and maximum force of the sample.

[0040] The test results are as follows: Table 1 Results of Mechanical Strength Test of Rubber Compound sample Example 7 Specimen width (W) (mm) 6 Sample thickness (t) (mm) 2 Original gauge length (mm) 10 Extensometer gauge length (mm) 10 Maximum force (Fm) (N) 93.492 Elongation at break (Eb) (%) 1819.03 Tensile strength (TS) (MPa) 7.791 hardness 63A It can be seen that the compound obtained by the present invention has excellent mechanical strength and high temperature resistance. This excellent performance is due to the good mechanical strength and high temperature resistance of the core raw material, fluorosilicone raw rubber.

[0041] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. Fluorosilicone gum, characterized in that, By weight parts, including the following raw materials: D3F: 50-99 parts; D4 vi : 0.01-10 parts; Silicon alcohol potassium catalyst prepolymer: 0.01-10 parts; Neutralizing agent: 0.01-10 parts; Among them, the silicon alcohol potassium catalyst prepolymer includes the following raw materials by weight parts: Potassium base: 0.1-3 parts; D4: 90-100 parts; End-capping agent: 0.001-2 parts.

2. A fluoro-silicone gum according to claim 1, wherein, The potassium base is KOH, the end-capping agent is tetramethyl divinyl disiloxane; the neutralizing agent is acetic acid.

3. A process for the preparation of fluoro-silicone gum, characterized in that, Including the following steps: (1) The mixture of D3F and D4 vi is vacuum dewatered, and then a potassium silanolate catalyst is added to the prepolymer, and the polymerization is carried out under the atmosphere of inert gas to obtain an intermediate product; (2) Mix the intermediate product with the neutralizing agent, and vacuum dehydrate to obtain fluorosilicone raw rubber.

4. The method of claim 3, wherein the fluorosilicone gum is prepared by the steps of: In step (1), the vacuum dehydration is specifically: vacuum dehydration at 40-70℃ for 4-5 H; the reaction temperature of the polymerization reaction is 60-120℃, and the reaction time is 0.1-7 H.

5. The process for the preparation of fluoro-silicone gum as claimed in claim 3, wherein, In step (2), the intermediate product is cooled to 10-30℃ before mixing with the neutralizing agent; the vacuum dehydration is specifically: vacuum dehydration at 130-160℃ for 2-3 H.

6. The method for preparing fluorosilicone raw rubber according to claim 3, characterized in that, In step (1), the preparation process of the silicon alcohol potassium catalyst prepolymer is: vacuum dehydration of the mixture of potassium base, D4 and end-capping agent, then heating under inert gas atmosphere, and stirring to generate silicon alcohol potassium catalyst prepolymer.

7. A process for the preparation of fluoro-silicone gum according to claim 6, characterized in that, Vacuum dehydration at 40-70℃ for 2-3 H, and then continue to heat to 60-90℃ under inert gas atmosphere.

8. Use of a fluoro-silicone gum in the preparation of a masticated gum, characterized in that, By weight parts, the mixing rubber includes the following raw materials: Fluorosilicone raw rubber: 90-110 parts; Silicon dioxide: 10-50 parts; Hydroxyl fluorosilicone oil: 1-10 parts; Zinc stearate: 0.01-1 parts; Among them, the fluorosilicone raw rubber is the fluorosilicone raw rubber of claim 1.