Preparation method of butyl rubber based on modified filler

Abstract

The invention discloses a preparation method of butyl rubber based on a modified filler, the filler is modified by using a silane modifier and stearic acid, the reinforcing property and dispersity of the filler are improved, and the filler is added into the butyl rubber as a substitute of the filler, so that the mechanical property and aging resistance of the butyl rubber are improved. The modified filler is used as a filler and is mixed with halogenated butyl rubber, vulcanized resin, zinc oxide, a coloring agent and a plasticizer in an internal mixer, and the mixed rubber is vulcanized, so that the physical and mechanical properties, namely the Rockwell hardness, the breaking strength, the elongation at break and the aging resistance, are improved compared with rubber which uses a conventional filler in the same formula.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a method for preparing butyl rubber based on a modified filler. Background Art

[0002] Rubber fillers, also known as fillers, generally refer to inorganic or organic substances added to rubber. The main function of fillers is to increase the volume of rubber and reduce costs, while also improving the processing and performance of rubber. First, by adding an appropriate amount of fillers, the hardness of the rubber can be increased, making it more durable and stable. Second, certain fillers such as carbon black and white carbon black can significantly improve the wear resistance of rubber and extend the service life of rubber products. Third, the addition of fillers can reduce the amount of rubber used, thereby reducing production costs, which is especially important for large-scale production of rubber products. Fourth, some fillers can improve the processing properties of rubber, such as increasing the fluidity of rubber, making it easier to mold and process.

[0003] Talc is a common filler in the rubber industry. Its primary component is hydrous magnesium silicate. It is chemically stable and can bond well with the rubber matrix. Its particle structure effectively enhances the mechanical strength of rubber products while reducing material density. In tires, seals, and other products, adding appropriate amounts of talc can improve the rubber's tensile properties and tear resistance.

[0004] However, talc powder tends to agglomerate during the rubber addition process, leading to uneven dispersion, an increase in white spots on the surface and interior of the finished product, and reduced reinforcement effectiveness. During the rubber compounding process, rubber breakage is also common, impacting production efficiency. Furthermore, the finished product's hardness and tensile strength also decrease, resulting in the product failing to achieve the expected hardness and strength. Summary of the Invention

[0005] In response to the above technical problems, the present invention provides a method for preparing butyl rubber based on modified fillers. The filler is modified by using a silane modifier and stearic acid to improve the reinforcement and dispersibility of the filler, and the filler is added to butyl rubber as a substitute for conventional fillers to improve the mechanical properties and aging resistance of the butyl rubber.

[0006] In order to achieve the above object, the present invention provides a method for preparing butyl rubber based on a modified filler, comprising the following steps: The preparation steps of the modified filler are as follows: (1) Filler and modifier ratio: weigh filler, silane modifier and stearic acid in a ratio of 100:0.5-2:1-1.5; (2) Preparation of modified solution: Pour the silane modifier and stearic acid into anhydrous ethanol and heat to 60-80°C. After they are completely dissolved, stir evenly to prepare solution B; (3) Preparation of filler suspension: Pour the filler into anhydrous ethanol and prepare suspension A using a high-speed stirring disperser; (4) Pour suspension A and solution B into the same container and mix them thoroughly using a high-speed stirring disperser; (5) The mixed liquid is distilled to remove anhydrous ethanol to obtain a modified filler.

[0007] The silane modifier is selected from any one of N-[3-(trimethoxysilyl)propyl]butan-1-amine, N-imidazolepropyltrimethoxysilane, and 3-(1-imidazole)-propylaminopropyltrimethoxysilane.

[0008] Preferably, the filler in step (1) is one of talc, hydrotalcite or calcined kaolin; preferably talc.

[0009] Furthermore, the filler in step (1) is talc powder with a mesh number of not less than 4000.

[0010] Preferably, the dispersing solvent used in step (2) is anhydrous ethanol.

[0011] Preferably, the dispersing solvent used in step (3) is anhydrous ethanol.

[0012] Preferably, the distillation temperature in step (5) is 80°C.

[0013] The steps for preparing the rubber compound are as follows: (6) Weigh 100 parts of halogenated butyl rubber, 60-80 parts of modified talc, 3-5 parts of zinc oxide, 0.5-1 part of vulcanized resin and 1-3 parts of plasticizer respectively; (7) Add 100 parts of halogenated butyl rubber and 30-40 parts of modified talc into an internal mixer, set the mixer speed to 20 RPM, and keep stirring for 120-180 seconds; (8) Add the remaining 30-40 parts of modified talc and 1-3 parts of plasticizer and keep stirring for 120-180 seconds; (9) Add 0.5-1 parts of vulcanized resin and 3-5 parts of zinc oxide and stir for 50-70 seconds; (10) The mixed rubber after internal mixing is pressed evenly on an open mixing mill to obtain the desired mixed rubber.

[0014] The vulcanized resin is brominated octylphenol formaldehyde vulcanized resin.

[0015] The plasticizer is low-density polyethylene wax with a density of 0.90-0.93 g / cm3 about.

[0016] The vulcanization temperature is 185-190°C and the vulcanization pressure is 12-16MPa.

[0017] The beneficial effects of the present invention are: 1. The use of talc modified with silane modifier and stearic acid reduces the agglomeration of the powder, significantly improves its dispersibility in rubber, and significantly reduces the number of white spots.

[0018] 2. When using modified fillers in rubber, replacing an equal amount of conventional fillers, the rubber's physical and mechanical properties, including hardness, tensile strength, and 300% elongation, are improved. Furthermore, due to the coupling effect of the silane modifier, the rubber's aging resistance is enhanced. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention are further explained below with reference to specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the claims. Any modifications or substitutions made to the technical solutions of the present invention by those skilled in the art without creative effort shall fall within the scope of protection of the present invention.

[0020] (1) Preparation method of butyl rubber based on modified filler In the Examples and Comparative Examples, the filler used was talc (4000 mesh), the modifiers used were silane modifiers and stearic acid, the vulcanized resin used was TB710 vulcanized resin, and the plasticizer used was dimethyl silicone oil. The silane modifier was selected from any one of N-[3-(trimethoxysilyl)propyl]butan-1-amine, N-imidazolylpropyltrimethoxysilane, and 3-(1-imidazolyl)-propylaminopropyltrimethoxysilane.

[0021] Example 1 Preparation of modified talc: (1) Weigh 100 parts of talc, 2 parts of N-[3-(trimethoxysilyl)propyl]butan-1-amine, and 1.5 parts of stearic acid respectively by weight; (2) Add talc powder to 150 parts of anhydrous ethanol and prepare suspension A using a high-speed stirring dispersor; (3) Add N-[3-(trimethoxysilyl)propyl]butan-1-amine and stearic acid to 50 parts of anhydrous ethanol and heat in a water bath to 60°C while stirring. After they are completely dissolved, stir evenly to prepare solution B. (4) Pour suspension A and solution B into the same container, heat in a water bath at 60°C, and mix thoroughly using a high-speed stirring disperser; (5) The mixed liquid is heated to 80°C for distillation while stirring until the anhydrous ethanol is completely evaporated to obtain modified talc.

[0022] Preparation of butyl rubber based on modified talc: (6) Weigh 100 parts of halogenated butyl rubber, 80 parts of modified talc, 5 parts of zinc oxide, 1 part of vulcanized resin and 2 parts of plasticizer respectively by weight; (7) Add 100 parts of halogenated butyl rubber and 40 parts of modified talc into an internal mixer, set the mixer speed to 20 RPM, and keep stirring for 180 seconds; (8) Add the remaining 40 parts of modified talc and 2 parts of plasticizer and keep stirring for 180 seconds; (9) Add vulcanized resin and zinc oxide and stir for 70 seconds; (10) The mixed rubber after internal mixing is pressed on an open mixing mill for 5 times to obtain the desired mixed rubber.

[0023] The preparation steps are the same as those in Example 1, except that the dissolution conditions in step (3) are adjusted.

[0024] Table 1. Modifier solution states under different dissolution conditions

[0025] It can be seen that the modifiers cannot be dissolved in water, but both modifiers can be dissolved in anhydrous ethanol under heating.

[0026] The preparation steps are the same as those in Example 1, except for the distillation temperature in step (5).

[0027] Table 2. State of modified talc at different distillation temperatures

[0028] When the temperature is 90°C, the surface-modified stearic acid will melt and precipitate into agglomerates, so 80°C is preferably used as the distillation temperature.

[0029] Example 2 The silane modifier is N-imidazolepropyltrimethoxysilane, and the other steps are the same as in Example 1.

[0030] Example 3 The silane modifier is 3-(1-imidazolyl)-propylaminopropyltrimethoxysilane, and the other steps are the same as in Example 1.

[0031] Comparative Example 1 The steps for preparing the butyl rubber are the same as those in Example 1, except that only talcum powder is used instead of modified talcum powder. The steps are as follows: (1) Weigh 100 parts of halogenated butyl rubber, 80 parts of talc, 5 parts of zinc oxide, 1 part of vulcanized resin and 2 parts of plasticizer respectively by weight; (2) Add 100 parts of halogenated butyl rubber and 40 parts of modified talc into an internal mixer, set the mixer speed to 20 RPM, and keep stirring for 180 seconds; (3) Add the remaining 40 parts of modified talc and 2 parts of plasticizer and keep stirring for 180 seconds; (4) Add vulcanized resin and zinc oxide and stir for 70 seconds; (5) Press the mixed rubber after internal mixing on an open mixing mill 5 times to obtain the desired mixed rubber.

[0032] Comparative Example 2 The preparation steps are the same as those in Example 1, except that only stearic acid is used as the modifier in the preparation of the modified talc.

[0033] Comparative Example 3 The preparation steps are the same as those in Example 1, except that in the preparation of the modified talc, only N-[3-(trimethoxysilyl)propyl]butan-1-amine is used as the modifier, and stearic acid is not used.

[0034] Comparative Example 4 The preparation steps were the same as those in Example 1, except that during the preparation of the modified talc, the modifier was replaced with bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69 coupling agent) in equal amounts, the amount of stearic acid remained unchanged, and the distillation temperature was changed.

[0035] Comparative Example 5 The preparation steps are the same as those in Example 1, except that during the preparation of the modified talc, the modifier is replaced with an equal amount of γ-aminopropyltriethoxysilane (KH-550 coupling agent), and the amount of stearic acid remains unchanged.

[0036] (2) Performance testing The rubber mixtures of Examples 1-3 and Comparative Examples 1-5 were vulcanized at a temperature of 185° C. for 320 s and a pressure of 16 MPa. Test blocks and test pieces that met the standards were prepared in accordance with GB / T 2411-2008 “Plastics and hard rubber - Determination of indentation hardness (Shore hardness) using a durometer”, GB / T 529-2009 “Rubber, vulcanized or thermoplastic - Determination of tensile strength”, and GBT 7759.1-2015 “Rubber, vulcanized or thermoplastic - Determination of compression set”. The Shore A hardness, tensile strength, 300% modulus of elongation, and compression set of the test blocks and test pieces were measured.

[0037] Table 3. Physical and mechanical properties of rubber

[0038] The mixed rubbers of Examples 1-3 and Comparative Examples 1-5 were vulcanized at a temperature of 185° C., a time of 320 s, and a pressure of 16 MPa to prepare 500 corresponding products. Their appearance was observed, and the number of white spots was recorded.

[0039] Table 4. Product Appearance

[0040] The rubber mixtures from Examples 1-3 and Comparative Examples 1-5 were vulcanized at 185°C for 320 seconds at a pressure of 16 MPa. Test blocks and test pieces meeting the standards of GB / T 2411-2008 and GB / T 529-2009 were prepared. These test blocks and test pieces were placed in a stability testing chamber at 60°C and 75% relative humidity for accelerated aging. After 30 days of accelerated aging, the test blocks and test pieces were removed and their Shore A hardness, tensile strength, and 300% modulus of elongation were measured.

[0041] Table 5. Physical and mechanical properties after accelerated aging

[0042] (3) Evaluation From the various performance results of the mixed rubbers of Examples 1-3 and Comparative Examples 1-5, it can be seen that the physical and mechanical properties and aging resistance of the butyl rubber of the present invention are improved by using a modified filler (talc) in the butyl rubber, and the powder dispersibility of the talc is improved.

[0043] Among them, it can be seen from Examples 1-3 and Comparative Example 1 that the modified talc has better reinforcement effect and significantly improved physical and mechanical properties than ordinary talc.

[0044] As can be seen from Examples 1-3 and Comparative Example 2, the modified talc without the addition of a silane modifier exhibits poor reinforcement and anti-aging properties, comparable to those of ordinary talc. Furthermore, as can be seen from Examples 1-3 and Comparative Example 3, the absence of the modifier, stearic acid, significantly reduces the dispersibility of the modified talc, leading to a significant increase in white spots in the vulcanized product. This uneven dispersion also results in a certain loss of physical and mechanical reinforcement.

[0045] It can be concluded from Example 1 and Comparative Example 5 that N-[3-(trimethoxysilyl)propyl]butan-1-amine used in Example 1 has a better effect of enhancing physical and mechanical properties than γ-aminopropyltriethoxysilane (KH-550 coupling agent) used in Comparative Example 5.

[0046] In addition, from the accelerated aging test, Examples 1-3 and Comparative Examples 1-5 show that the aging resistance of talc modified with the silane modifier of the present application is significantly improved, and the aging resistance is better than that of bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69 coupling agent) used in Comparative Example 4.

[0047] It can be seen that the preparation method of butyl rubber based on the modified filler formed in the present invention can effectively improve the physical and mechanical properties and aging resistance of butyl rubber, and enhance the dispersibility of the powder.

Claims

1. A method for preparing butyl rubber based on modified filler, characterized in that: The following steps are involved: (1) Preparation of modified solution: Pour the silane modifier and stearic acid into anhydrous ethanol, heat and stir to dissolve, and then modify the solution; (2) After mixing the modified solution with the filler solution, the modified filler is obtained by distilling off the solvent after high-speed stirring and dispersion; (3) adding halogenated butyl rubber and part of modified filler into an internal mixer for internal mixing; (4) Add the remaining modified filler and plasticizer, stir and mix, then add the vulcanized resin and zinc oxide for internal mixing to obtain a rubber mix, and press it evenly on an open mill to obtain the desired butyl rubber.

2. The method for preparing butyl rubber based on modified filler according to claim 1, characterized in that: The silane modifier is selected from any one of N-[3-(trimethoxysilyl)propyl]butan-1-amine, N-imidazolepropyltrimethoxysilane, and 3-(1-imidazole)-propylaminopropyltrimethoxysilane.

3. The method for preparing butyl rubber based on modified filler according to claim 2, characterized in that: The mass ratio of the filler, the silane modifier and the stearic acid is 100:0.5-2:1-1.

5.

4. The method for preparing butyl rubber based on modified filler according to claim 1, characterized in that: The filler in step (2) is one of talc, hydrotalcite or calcined kaolin; preferably talc.

5. The method for preparing butyl rubber based on modified filler according to claim 1, characterized in that: The filler described in step (2) has a mesh size of not less than 4000.

6. The method for preparing butyl rubber based on modified filler according to claim 1, characterized in that: The step (3) or the step (4) comprises 100 parts of halogenated butyl rubber, 60-80 parts of modified filler, 3-5 parts of zinc oxide, 0.5-1 part of vulcanized resin and 1-3 parts of plasticizer.

7. The method for preparing butyl rubber based on modified fillers according to claim 1, characterized in that: The vulcanized resin is brominated octylphenol formaldehyde vulcanized resin.

8. The method for preparing butyl rubber based on modified fillers according to claim 1, characterized in that: The plasticizer is low-density polyethylene wax.

9. The method for preparing butyl rubber based on modified filler according to claim 1, characterized in that: The vulcanization temperature is 185-190°C and the vulcanization pressure is 12-16MPa.

10. A butyl rubber based on modified filler with aging resistance, characterized in that: The method according to any one of claims 1 to 9 has a Shore A hardness greater than 50, a tensile strength greater than 7.0 MPa, a 300% modulus of elongation greater than 2.5 MPa, and a compression set less than 12% after 30 days of accelerated aging.

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