Ultraviolet irradiated silica aerogel modified chlorobutyl rubber

Abstract

This invention belongs to the field of rubber materials, specifically relating to a UV-irradiated silica aerogel-modified chlorinated butyl rubber. The preparation method includes the following steps: (1) in-situ modification of silica aerogel and silane coupling agent KH570 using the principle of alcohol removal condensation to obtain silane coupling agent-modified aerogel; (2) mixing the silane coupling agent-modified aerogel with chlorinated butyl rubber on a two-roll mill; (3) heating the mixed material in a torque rheometer as a modification masterbatch; (4) mixing chlorinated butyl rubber with filler and then internally mixing; (5) mixing the rubber with the modification masterbatch, vulcanizing agent, and accelerator for internal mixing and vulcanization. This invention, by introducing UV-irradiated silane coupling agent KH570 to modify the aerogel, and first mixing and heating it with chlorinated butyl rubber, then using it as a modification masterbatch for internal mixing with chlorinated butyl rubber, can significantly reduce the torque of chlorinated butyl rubber and improve its tensile strength and hardness.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials, specifically relating to a chlorinated butyl rubber modified by ultraviolet irradiated silica aerogel. Background Technology

[0002] Chlorinated butyl rubber, also known as chloroprene rubber, is primarily polymerized from chloroprene. This rubber possesses excellent damping properties, effectively controlling vibrations, and is therefore widely used in aerospace, vibration damping, and noise reduction. Because its structure is mainly based on a saturated butyl backbone, chlorinated butyl rubber retains many IIR (Integrated Inertial Resonance) characteristics, such as excellent airtightness and a low glass transition temperature. It also possesses unique properties, such as rapid vulcanization, diverse vulcanization methods, and strong vulcanization adhesion, making it widely used in automotive parts and seals. However, as an excellent elastic material, chlorinated butyl rubber also has some drawbacks. First, from a mechanical property perspective, its strength and hardness are relatively low, which may lead to poor performance in some high-strength applications. Second, it exhibits poor stability at high temperatures and is prone to aging, affecting its mechanical properties and service life. Regarding heat resistance, it may soften and lose elasticity, limiting its application in high-temperature environments. Furthermore, at low temperatures, its toughness may be affected, exhibiting a degree of brittleness, which may limit its application range in cold climates. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a UV-irradiated silica aerogel-modified chlorinated butyl rubber.

[0004] The technical solution adopted in this invention is as follows: A method for preparing ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber includes the following steps: (1) Silica aerogel and silane coupling agent KH570 were modified in situ using the principle of alcohol removal condensation. Then, they were irradiated with ultraviolet light and dried to obtain silane coupling agent modified aerogel. (2) The silane coupling agent modified aerogel prepared in step (1) is mixed with chlorinated butyl rubber in a two-roll mill; (3) The material mixed in step (2) is heated in a torque rheometer to be used as a modified masterbatch; (4) Mix chlorinated butyl rubber with filler and then perform internal mixing; (5) Mix the rubber after internal mixing in step (4) with the modified masterbatch, vulcanizing agent and accelerator after heat treatment in step (3) and perform open mixing and vulcanization.

[0005] In step (1), the mass ratio of silica aerogel to silane coupling agent KH570 is 100:3.

[0006] In step (1), ultraviolet irradiation is performed at 80 °C. In step (2), the mass ratio of silane coupling agent modified aerogel to chlorinated butyl rubber is 40:60.

[0007] In step (3), the heating temperature is 80-180℃.

[0008] In step (4), chlorinated butyl rubber is mixed and kneaded with stearic acid, zinc oxide, naphthenic oil, antioxidant, anti-aging agent, carbon black and petroleum resin.

[0009] In step (5), the mass ratio of chlorinated butyl rubber to silica aerogel in the heat-treated modified masterbatch of step (3) is 100:2-10.

[0010] In step (5), the vulcanization temperature is 160-180℃.

[0011] The beneficial effects of this invention are as follows: By introducing ultraviolet-irradiated modified silica aerogel, and pre-mixing and heating it with chlorinated butyl rubber before using it as a modified masterbatch for open milling, the torque of chlorinated butyl rubber can be significantly reduced, and its tensile strength and hardness can be improved. This enhances the sealing performance, long-term reliability, and service life of gaskets and washers. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0013] Figure 1 shows the preparation process of aerogel-modified chlorinated butyl rubber; Figure 2 is a schematic diagram of nano-SiO2 modified with silane coupling agent; Figure 3 shows the vulcanization curves of chlorinated butyl rubber; (a) different aerogel contents, (b) different aerogel treatment temperatures; Figure 4 shows the effect of aerogel treatment temperature on the tensile properties of modified chlorinated butyl rubber. Figure 5 shows the tensile properties and torque of aerogel-modified chlorinated butyl rubber; Figure 6 shows the effect of aerogel content on the thermal conductivity of modified chlorinated butyl rubber; Figure 7 shows the infrared spectra of the raw materials and the aerogel before heat treatment. Figure 8 shows the infrared spectra of aerogels and chlorinated butyl rubber mixtures treated at different temperatures; Figure 9 shows the carbon residue curves (a) and DTG curves (b) of rubbers with different aerogel contents. Figure 10 shows the carbon residue curves (a) and DTG curves (b) of rubber at different aerogel treatment temperatures. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0015] Example 1: (1) 100 parts of silica aerogel and 3 parts of silane coupling agent KH570 were used. In-situ modification was carried out using the principle of alcohol removal condensation. KH570 was dissolved in anhydrous ethanol, and then the aerogel was mixed with the KH570 solution. The schematic diagram of the chemical reaction process is shown below. Figure 2 As shown. Subsequently, the groups were set up and dried by ultraviolet irradiation for 20 min at room temperature and 80 °C, respectively.

[0016] (2) The aerogel from step (1) and chlorinated butyl rubber are mixed in a ratio of 40:60 on a two-roll mill at 60°C.

[0017] (3) Take 66 cm of the aerogel from step (2) and chlorinated butyl rubber. 3 In a torque rheometer, the sample was treated at a speed of 150 r / min and at temperatures of 80, 100, 120, 150, and 180 ℃ for 10 min, and then removed for later use.

[0018] (4) Internal mixing: Set the internal mixing temperature to 100 ℃, add rubber and other materials except aerogel, sulfur and accelerator according to the formula in Table 1, mix evenly and take out.

[0019] (5) Opening: Divide the rubber from step (2) into groups, set the roller gap to 1 mm and the roller temperature to 60 ℃, and add the modified silica aerogel, sulfur and accelerator prepared in step (3) in sequence according to the formula. After mixing, mark them in sequence.

[0020] (6) Vulcanization: Use a flat vulcanizer to press the rubber sample into a size of 18 cm × 18 cm × 2 mm. The vulcanization temperature and time are 170 ℃ and 10 min.

[0021] Table 1. Parameter settings for each sample in Example 1 Example 2: (1) 100 parts of silica aerogel and 3 parts of silane coupling agent KH570 were used. In-situ modification was carried out using the principle of alcohol removal condensation. KH570 was dissolved in anhydrous ethanol, and then the aerogel was mixed with the KH570 solution. The schematic diagram of the chemical reaction process is shown below. Figure 2 As shown. Subsequently, the groups were set up and irradiated with ultraviolet light at room temperature and 80 °C for 20 min, respectively, and then dried.

[0022] (2) The aerogel from step (1) and chlorinated butyl rubber are mixed in a ratio of 40:60 on a two-roll mill at 60°C.

[0023] (3) Take 66 cm of the aerogel from step (2) and chlorinated butyl rubber. 3 In a torque rheometer, the sample was processed at a speed of 150 r / min and a temperature of 120℃ for 10 min, and then removed for later use.

[0024] (4) Set the mixing temperature to 100 ℃. After adding the rubber, add the various materials in the order of percentage in Table 2, mix them evenly, and then take them out.

[0025] (5) Divide the rubber from step (4) into groups, set the roller gap to 1 mm and the roller temperature to 60 ℃, add the aerogel, sulfur and accelerator treated in step (3) in sequence according to the formula, mix well and mark them in sequence.

[0026] (6) Use a flat vulcanizing apparatus to press the rubber sample into a size of 18 cm × 18 cm × 2 mm. The vulcanization temperature and time are 170℃ and 10 min.

[0027] Table 2 Parameter settings for each sample in Example 2 Test example: Figure 3 The vulcanization curves of chlorinated butyl rubber are shown in (a) for different aerogel contents and (b) for aerogel treatment temperatures. It can be seen that the addition of aerogel significantly reduces the torque of the rubber. This may be because the addition of aerogel isolates the vulcanizing agent, leading to a reduction in active sites and decreased vulcanization activity. However, as the aerogel treatment temperature increases, there is no significant difference in torque, indicating little impact on vulcanization activity.

[0028] Table 3 shows the vulcanization time of aerogel-modified chlorinated butyl rubber. Comparing the scorch time, semi-vulcanization time, and full vulcanization time, it can be found that the differences between the samples in each group are not particularly large, which indicates that the treatment temperature of the aerogel has little effect on the vulcanization performance of the rubber compound.

[0029] Table 3. Vulcanization time of aerogel-modified chlorinated butyl rubber Table 4 shows the loss tangent (tanδ) of aerogel-modified chlorinated butyl rubber. It can be observed that CR-T150 has the largest loss factor (tanδ) at 0.732, followed by CR-T120. This indicates that the vulcanized rubber has high mechanical damping capacity or energy loss, implying high shock absorption capability.

[0030] Table 4. tanδ of aerogel-modified chlorinated butyl rubber Table 5 shows the tensile properties of rubber compounds with different aerogel contents. The aerogel addition amount first increases and then decreases from 0 phr to 10 phr. The overall tensile properties of the rubber increase, with CR-Si5 showing the highest tensile strength at 15.69 MPa, an increase of 17.2%. The strength decreases after the addition amount exceeds 5 phr, but is still greater than that of pure rubber. This indicates that the addition of aerogel can effectively improve the mechanical properties of chlorinated butyl rubber.

[0031] Table 5 Tensile properties of compounds with different aerogel contents Figure 4 The effect of aerogel treatment temperature on the tensile properties of modified chlorinated butyl rubber is shown in the figure. The tensile strength initially increases and then decreases with increasing aerogel treatment temperature. The elongation at break also initially increases and then decreases with increasing aerogel treatment temperature from 80 ℃ to 180 ℃. However, a significant decrease in both tensile strength and elongation at break occurs between 150 ℃ and 180 ℃, indicating that excessively high aerogel treatment temperatures reduce the mechanical properties of the rubber. The rubber exhibits the best mechanical properties at an aerogel treatment temperature of 120 ℃.

[0032] Figure 5 This figure compares the effects of aerogel treatment temperature on the tensile properties and torque of modified chlorinated butyl rubber. The graph shows that the stable torque of the aerogel initially increases and then decreases, which is consistent to some extent with the trend of the mechanical properties of the modified rubber.

[0033] Figure 6 The effect of aerogel content on the thermal conductivity of modified chlorinated butyl rubber was investigated. With increasing aerogel content, the thermal conductivity of the rubber first increased and then decreased. The highest thermal conductivity was observed at 5 phr of aerogel addition, but it was still lower than at 0 phr overall, indicating that the addition of aerogel reduces the thermal conductivity of the rubber to some extent, thus enhancing its insulation performance.

[0034] Figure 7 The infrared spectra of the raw materials and the aerogel before heat treatment. For example... Figure 9As shown, the infrared spectrum of the raw material aerogel exhibits multiple characteristic peaks, corresponding to different functional groups and chemical bonds. The main observed absorption peaks include those located at 2950 cm⁻¹. -1 The CH stretching vibration peaks, which are usually generated due to the presence of carbon chains, are located at 1388 cm⁻¹. -1 1229cm -1 Stretch vibration of the C-C bond was observed; located at 1469 cm. -1 Bending vibrations of CH bonds were observed.

[0035] The infrared spectrum of the mixture of silica aerogel and silane coupling agent (KH570) did not show a peak of KH570, possibly because the concentration of KH570 was low and its signal in the infrared spectrum was weak and difficult to detect.

[0036] Figure 8 Infrared spectra of aerogels and chlorinated butyl rubber mixtures treated at different temperatures are shown. Infrared spectral analysis of the mixture of chlorinated butyl rubber and silica aerogel showed that its infrared spectrum was largely consistent with that of individual chlorinated butyl rubber and silica aerogels, exhibiting similar characteristic peaks and absorption peak shapes. Furthermore, infrared spectral analysis of the mixture at different treatment temperatures revealed that its infrared spectrum remained stable, unaffected by the treatment temperature.

[0037] Figure 9 The TG (TG) curves (a) and DTG (DTG) curves of the rubber compounds with different aerogel contents are shown in Figure (b). The similar maximum decomposition peaks of the samples indicate that although the amount of aerogel added varies, it has little effect on the maximum decomposition temperature of chlorinated butyl rubber, which remains relatively stable at around 410℃. This may suggest that the aerogel content does not significantly alter the thermal stability of chlorinated butyl rubber within a certain range.

[0038] Figure 10 The graphs show the TG and DTG curves of the rubber compounds treated with different aerogels. As can be seen from the graph, the maximum weight loss temperatures of the samples are similar, generally around 410℃, further demonstrating that the aerogel treatment temperature has little effect on the decomposition temperature of chlorinated butyl rubber. This consistent result may indicate that the stable thermal properties of chlorinated butyl rubber are not significantly affected by the amount of aerogel added or the treatment temperature.

[0039] Based on the above performance comparison, we can find that: For the CIIIR system, silica aerogel is an inorganic filler with very high adaptability. According to current data, when the content of aerogel accounts for about 5% of the total system content and the processing temperature is 120℃, its mechanical properties reach a relatively ideal range.

[0040] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A type of chlorinated butyl rubber modified with ultraviolet-irradiated silica aerogel, characterized in that... Its preparation method includes the following steps: (1) Silica aerogel and silane coupling agent KH570 were modified in situ using the principle of alcohol removal condensation. Then, they were irradiated with ultraviolet light and dried to obtain silane coupling agent modified aerogel. (2) The silane coupling agent modified aerogel prepared in step (1) is mixed with chlorinated butyl rubber in a two-roll mill; (3) The material mixed in step (2) is heated in a torque rheometer to be used as a modified masterbatch; (4) Mix chlorinated butyl rubber with filler and then perform internal mixing; (5) Mix the rubber after internal mixing in step (4) with the modified masterbatch, vulcanizing agent and accelerator after heat treatment in step (3) and perform open mixing and vulcanization.

2. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (1), the mass ratio of silica aerogel to silane coupling agent KH570 is 100:

3.

3. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (1), ultraviolet irradiation is performed at 80 °C.

4. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (2), the mass ratio of silane coupling agent modified silica aerogel to chlorinated butyl rubber is 40:

60.

5. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (3), the heating temperature is 80-180℃.

6. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (4), chlorinated butyl rubber is mixed and kneaded with stearic acid, zinc oxide, naphthenic oil, antioxidant, anti-aging agent, carbon black and petroleum resin.

7. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (5), the mass ratio of chlorinated butyl rubber to silica aerogel in the heat-treated modified masterbatch of step (3) is 100:2-10.

8. The ultraviolet-irradiated silica aerogel-modified chlorinated butyl rubber according to claim 1, characterized in that: In step (5), the vulcanization temperature is 160-180℃.

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