Fluorosilicone rubber as well as preparation method and application thereof

Abstract

The invention provides fluorinated silicone rubber as well as a preparation method and application thereof, and belongs to the field of rubber manufacturing. The specific siloxane cross-linking agent is added into the formula for preparing the fluororubber, so that the mechanical property and the heat resistance of the fluororubber are enhanced. The surface, attached to the fluororubber, of the silicone rubber can be co-vulcanized with the siloxane cross-linking agent, so that the silicone rubber and the fluororubber are bonded more firmly. Compared with fluorosilicone rubber in the prior art, the fluorosilicone rubber prepared by the preparation method disclosed by the invention has more excellent mechanical property and adhesive property, can keep excellent adhesive property at high temperature, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the field of rubber manufacturing, and specifically relates to fluorosilicone rubber and a preparation method and application thereof. Background Art

[0002] Fluororubber is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of the main chain or side chain. The introduction of fluorine atoms gives the rubber excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance and atmospheric aging resistance. It has been widely used in aerospace, aviation, automobiles, petroleum and household appliances, and is an irreplaceable key material in the cutting-edge defense industry. Silicone rubber is a linear high molecular weight polysiloxane, the main chain of which is composed of silicon atoms and oxygen atoms alternately (-Si-O-Si-), and organic groups are connected to the side chains. This structure gives silicone rubber excellent heat resistance and weather resistance. Fluorosilicone rubber combines the excellent properties of both fluororubber and silicone rubber, such as excellent oil resistance, solvent resistance, and chemical resistance. It is particularly suitable for some applications that require fuel resistance, such as auto parts seals, turbocharger pipes, films, etc. It has a wide range of applications in the automotive industry, aerospace and other fields.

[0003] The air intake and air outlet intercooling system of a turbocharged automobile engine is generally composed of components such as an air filter, a turbocharger, an intercooler and its connecting pipes. The gas pipeline is usually connected to a steel pipe by a rubber tube. With the good flexibility and vibration damping of rubber, it is convenient for pipeline layout and assembly, and can significantly improve the ability of the gas pipeline system to buffer vibration. The high-temperature resistant and cheap silicone and the oil-resistant fluororubber are blended and modified, that is, the inner lining of the hose is an oil-resistant rubber layer, and the other parts are a "fluorine inside and silicone outside" structure of silicone, so as to meet the engine use requirements and reduce costs at the same time. However, ordinary fluororubber is poorly combined with silicone and cannot be used. Especially when used at high temperatures, the high temperature will aggravate the damage to the interface between fluororubber and silicone rubber, making the two easier to peel off. Patent application document CN104327426A provides a formula of fluororubber with strong adhesion to silicone rubber, and the formula adds triallyl isocyanurate as a tackifier. Patent application document CN109054400A provides a high-adhesive and high-oil-resistant fluorosilicone formula, which adds triallyl cyanurate and tripropylene isocyanurate as curing accelerators. Patent application document CN112300579A enhances the bonding performance of fluorosilicone rubber and silicone rubber by adding a tackifier with a hydroxyl group at the end and trifluoropropyl and vinyl groups on the side chain. However, these technical solutions have the following problems: (1) The synthesis of the tackifier by introducing the tackifier is relatively cumbersome and difficult; (2) It is difficult to effectively improve the bonding performance of fluororubber and silicone rubber; (3) These tackifiers themselves have poor heat resistance and are easily volatilized and decomposed at high temperatures. These phenomena lead to the limited bonding strength between the two at room temperature and the inability to achieve bonding at high temperatures. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a fluorosilicone rubber and a preparation method and use thereof.

[0005] The invention provides a fluororubber compound rubber, which is prepared from fluororubber raw rubber, reinforcing filler, vulcanizing agent, siloxane crosslinking agent containing alkenyl group and metal oxide, wherein the mass ratio of the fluororubber raw rubber, reinforcing filler, vulcanizing agent, siloxane crosslinking agent containing alkenyl group and metal oxide is 100:10-60:0.1-10:1-10:1-10.

[0006] Furthermore, the mass ratio of the fluororubber raw rubber, reinforcing filler, vulcanizing agent, alkenyl-containing siloxane crosslinking agent and metal oxide is 100:20-40:1-5:2-6:3-7; preferably 100:30:3:4:5.

[0007] Furthermore, the fluororubber raw rubber is 246 type fluororubber;

[0008] The reinforcing filler is carbon black or diatomaceous earth;

[0009] The vulcanizing agent is a peroxide vulcanizing agent, preferably di-25;

[0010] The alkenyl-containing siloxane crosslinking agent is pentamethylpentavinylcyclopentasiloxane, tetramethyltetravinylcyclotetrasiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane or hexavinyldisiloxane;

[0011] The metal oxide is zinc oxide.

[0012] The present invention also provides a method for preparing the above fluororubber compound, which comprises the following steps: kneading fluororubber raw rubber, reinforcing filler, vulcanizing agent, alkenyl-containing siloxane crosslinking agent and metal oxide to obtain.

[0013] Furthermore, the banburying conditions are: banburying at 30-80° C. for 1-10 min, preferably: banburying at 60° C. for 5 min.

[0014] The present invention also provides the use of the fluororubber compound in bonding silicone rubber.

[0015] The present invention also provides a fluorosilicone rubber, which is a product obtained by heating and bonding the above fluororubber mixed rubber and silicone rubber.

[0016] The present invention also provides a method for preparing the fluorosilicone rubber, which comprises the following steps: heating and bonding the fluororubber mixed rubber and the silicone rubber to obtain the fluorosilicone rubber.

[0017] Furthermore, the heating condition is: heating at 140-160° C. for 2-6 hours, preferably: heating at 150° C. for 4 hours.

[0018] The present invention also provides the use of the above-mentioned fluorosilicone rubber in preparing a high-temperature resistant adhesive material, wherein the high-temperature resistant adhesive material is a turbocharger hose, a fuel system component, a seal, a sensor or a shielded cable material.

[0019] The present invention adds a specific siloxane crosslinking agent to the formula for preparing fluororubber, thereby enhancing the mechanical properties and heat resistance of the fluororubber. The surface of the silicone rubber and the fluororubber that fit together can be co-vulcanized with the siloxane crosslinking agent, so that the silicone rubber and the fluororubber are more firmly bonded. The tensile strength of the fluorosilicone rubber prepared by the present invention can reach 16-19PMa, the tear strength can reach 31-36N / mm, and the peel strength can reach up to 2.6N / mm; while the maximum tensile strength of the fluorosilicone rubber disclosed in the patent application document CN112300579A is only 10.9PMa, the maximum tear strength is only 25.9N / mm, and the maximum peel strength is only 2.23N / mm. Therefore, the fluorosilicone rubber prepared by the present invention has better mechanical properties and bonding properties than the fluorosilicone rubber in the prior art, and can also maintain excellent bonding properties (peel strength can reach 0.17-0.35N / mm) at high temperatures (200°C, 168h), and has broad application prospects.

[0020] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0021] The above contents of the present invention are further described in detail below through specific implementation methods in the form of examples. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. DETAILED DESCRIPTION

[0022] The raw materials and equipment used in the present invention are all known products, which are obtained by purchasing commercially available products.

[0023] Example 1: Preparation of fluororubber compound FKM-1

[0024] 100 g of 246 type fluororubber raw rubber, 30 g of N990 carbon black, 4 g of tetramethyltetravinylcyclotetrasiloxane, 5 g of zinc oxide, and 3 g of dipentadiene were added into an internal mixer and kneaded at 60° C. for 5 min to obtain a fluororubber compound FKM-1.

[0025] Example 2: Preparation of fluororubber compound FKM-2

[0026] 100 g of 246 type fluororubber raw rubber, 30 g of N990 carbon black, 4 g of pentamethylpentavinylcyclopentasiloxane, 5 g of zinc oxide, and 3 g of bis(2,5-pentadienyl)siloxane were added into an internal mixer and kneaded at 60° C. for 5 min to obtain a fluororubber compound FKM-2.

[0027] Example 3: Preparation of fluororubber compound FKM-3

[0028] 100 g of 246 type fluororubber raw rubber, 30 g of N990 carbon black, 4 g of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, 5 g of zinc oxide, and 3 g of dipentadiene were added to an internal mixer and kneaded at 60° C. for 5 min to obtain a fluororubber compound FKM-3.

[0029] Example 4: Preparation of fluororubber compound FKM-4

[0030] 100 g of 246 type fluororubber raw rubber, 30 g of N990 carbon black, 4 g of hexavinyl disiloxane, 5 g of zinc oxide, and 3 g of di-25-1 were added into an internal mixer and kneaded at 60° C. for 5 min to obtain a fluororubber compound rubber FKM-4.

[0031] Example 5: Preparation of fluorosilicone rubber FQ-1

[0032] After the fluororubber compound FKM-1 of Example 1 was re-refined on an open mill at 30°C and 1mm spacing, the test pieces were cut. After the silicone rubber was re-refined on an open mill at 30°C and 1mm spacing, the test pieces were also cut into test pieces of the same size as the fluororubber. The fluororubber test piece and the silicone test piece were tightly fitted and placed in an oven at 150°C for 4 hours to obtain the bonded test pieces. After taking out, they were cut into 15cm long and 20±0.5mm wide to obtain the fluorosilicone rubber FQ-1, and one end was peeled off 10mm for testing.

[0033] Example 6: Preparation of fluorosilicone rubber FQ-2

[0034] The method of reference embodiment 5 is different in that FKM-1 is replaced by FKM-2 to prepare fluorosilicone rubber FQ-2 for testing.

[0035] Example 7: Preparation of fluorosilicone rubber FQ-3

[0036] The method of reference embodiment 5 is different in that FKM-1 is replaced by FKM-3 to prepare fluorosilicone rubber FQ-3 for testing.

[0037] Example 8: Preparation of fluorosilicone rubber FQ-4

[0038] The method of reference embodiment 5 is different in that FKM-1 is replaced by FKM-4 to prepare fluorosilicone rubber FQ-4 for testing.

[0039] The following comparative samples are prepared by comparative examples.

[0040] Comparative Example 1: Preparation of fluororubber compound FKM-Q

[0041] 100 g of 246 type fluororubber raw rubber, 30 g of N990 carbon black, 4 g of triallyl isocyanurate, 5 g of zinc oxide, and 3 g of di-25 were added into an internal mixer and kneaded at 60° C. for 5 min to obtain a fluororubber compound FKM-Q.

[0042] Comparative Example 2: Preparation of fluorosilicone rubber FQ-Q

[0043] The method of reference embodiment 5 is different in that FKM-1 is replaced by FKM-Q to prepare fluorosilicone rubber FQ-Q for testing.

[0044] According to GB / T528-2009 standard, the mechanical properties of the fluororubber compounds prepared in Examples 1 to 4 and Comparative Example 1 were tested. The test results are shown in Table 1.

[0045] Table 1. Mechanical properties test results of fluororubber compounds

[0046]

[0047] From the results in Table 1, it can be seen that compared with the fluororubber compound prepared by adding triallyl isocyanurate, the addition of a siloxane crosslinking agent in the present invention can significantly improve the tear strength and elongation of the fluororubber compound. Different types of siloxane crosslinking agents have different effects on the improvement of tear strength and elongation, among which tetramethyltetravinylcyclotetrasiloxane has a more obvious improvement on tear strength, and hexavinyldisiloxane has a more obvious improvement on elongation.

[0048] The peeled ends of the fluorosilicone rubber test pieces prepared in Examples 5 to 8 and Comparative Example 2 were clamped on the upper and lower clamps of the tensile testing machine, respectively, and peeling was started at a speed of 50±2 mm / min. The equipment automatically recorded and plotted the peeling load curve of the sample, and the peeling strength was obtained respectively. The results are shown in Table 2.

[0049] Table 2. Peel strength test results of fluorosilicone rubber

[0050] serial number Peel strength (N / mm) Example 5 FQ-1 2.2 Example 6 FQ-2 2.6 Example 7 FQ-3 1.8 Example 8 FQ-4 1.7 Comparative Example 2 FQ-Q 0.57

[0051] It can be seen from the results in Table 2 that, compared with adding triallyl isocyanurate to fluororubber, adding a siloxane crosslinking agent to fluororubber in the present invention can significantly improve the peel strength of fluorosilicone rubber and enhance the adhesion between fluororubber and silicone rubber.

[0052] In order to further verify that the fluorosilicone rubber prepared in Examples 5 to 8 and Comparative Example 2 still has adhesion at high temperatures, the test samples of FQ-1, FQ-2, FQ-3, and FQ-4 were placed in an oven at 200°C for 168 hours and then their peel strength was tested. The results are shown in Table 3.

[0053] Table 3. Peel strength test results of fluorosilicone rubber at high temperature

[0054]

[0055]

[0056] It can be seen from Table 3 that after the fluororubber prepared by selecting the siloxane crosslinking agent is bonded to the silicone rubber, it still has good bonding performance at high temperature.

[0057] In summary, the present invention provides a fluorosilicone rubber and a preparation method and use thereof. The present invention adds a specific siloxane crosslinking agent to the formula for preparing fluororubber, thereby enhancing the mechanical properties and heat resistance of the fluororubber. The surface of the silicone rubber and the fluororubber that are in contact can be co-vulcanized with the siloxane crosslinking agent, so that the silicone rubber and the fluororubber are more firmly bonded. The fluorosilicone rubber prepared by the present invention has better mechanical properties and bonding properties than the fluorosilicone rubber in the prior art, and can maintain excellent bonding properties even at high temperatures, and has broad application prospects.

Claims

1. A fluororubber compound, characterized in that: It is prepared from fluororubber raw rubber, reinforcing filler, vulcanizing agent, olefinic siloxane crosslinking agent and metal oxide, wherein the mass ratio of the fluororubber raw rubber, reinforcing filler, vulcanizing agent, olefinic siloxane crosslinking agent and metal oxide is 100:10-60:0.1-10:1-10:1-10.

2. The fluororubber compound according to claim 1, characterized in that: The mass ratio of the fluororubber raw rubber, reinforcing filler, vulcanizing agent, alkenyl-containing siloxane crosslinking agent and metal oxide is 100:20-40:1-5:2-6:3-7; preferably 100:30:3:4:

5.

3. The fluororubber compound according to claim 1, characterized in that: The fluororubber raw rubber is 246 type fluororubber; The reinforcing filler is carbon black or diatomaceous earth; The vulcanizing agent is a peroxide vulcanizing agent, preferably di-25; The alkenyl-containing siloxane crosslinking agent is pentamethylpentavinylcyclopentasiloxane, tetramethyltetravinylcyclotetrasiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane or hexavinyldisiloxane; The metal oxide is zinc oxide.

4. A method for preparing the fluororubber compound according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: kneading fluororubber raw rubber, reinforcing filler, vulcanizing agent, olefin-containing siloxane crosslinking agent and metal oxide to obtain the product.

5. The method according to claim 4, characterized in that The banburying conditions are: banburying at 30-80° C. for 1-10 min, preferably: banburying at 60° C. for 5 min.

6. Use of the fluororubber compound according to any one of claims 1 to 3 in bonding silicone rubber.

7. A fluorosilicone rubber, characterized in that: The product is obtained by heating and bonding the fluororubber compound described in any one of claims 1 to 3 with silicone rubber.

8. A method for preparing the fluorosilicone rubber according to claim 7, characterized in that: The method comprises the following steps: heating and bonding the fluororubber mixed rubber and the silicone rubber to obtain the product.

9. The method according to claim 8, characterized in that The heating conditions are: heating at 140-160° C. for 2-6 hours, preferably: heating at 150° C. for 4 hours.

10. Use of the fluorosilicone rubber according to claim 7 in the preparation of high temperature resistant adhesive materials, wherein the high temperature resistant adhesive materials are turbocharger hoses, fuel system components, seals, sensors or shielded cable materials.

Images