Modified white carbon black as well as preparation method and application thereof

Abstract

The invention relates to modified white carbon black as well as a preparation method and application thereof. The modified white carbon black is obtained by modifying a styrene-alpha-methylstyrene copolymer. By virtue of interaction of macromolecules, the compatibility of the white carbon black and the styrene-butadiene rubber is improved, and the mechanical property of the composite material is effectively improved; besides, the modified white carbon black is used as an additive of a rubber composite material, so that the toughness of rubber can be obviously improved, the elongation at break can be improved, meanwhile, the wet skid resistance of a rubber product can be improved, and the modified white carbon black has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber materials, and particularly relates to modified white carbon black and a preparation method and application thereof. Background Art

[0002] Rubber materials are an extremely important type of polymer materials, and have been widely used in mining, transportation, construction, machinery, electronics and other fields. Styrene-butadiene rubber (SBR), also known as polystyrene butadiene copolymer, has mechanical properties, processing properties and product performance close to natural rubber. Some properties such as wear resistance, heat resistance, aging resistance and vulcanization speed are better than natural rubber. It can be used with natural rubber and a variety of synthetic rubbers. It is widely used in the production of tires, tapes, hoses, wires and cables, medical devices and various rubber products. It is the largest general synthetic rubber variety. Pure synthetic rubber still has deficiencies in strength and hardness, and needs to be reinforced by adding reinforcing agents.

[0003] Silica is one of the most widely used reinforcing agents in the rubber industry, which can increase the strength and wear resistance of rubber. However, due to the poor compatibility between silica and rubber and the interaction between silica particles, silica often agglomerates and precipitates during processing. In order to solve this problem, researchers have done a lot of work to improve the compatibility of silica with styrene-butadiene rubber. Wu Zhipeng et al. proposed a modification method in patent CN116903930A, grafting cardanol onto silica particles, and chemically crosslinking with rubber through the action of sulfur, thereby improving the compatibility of rubber and silica, significantly reducing the rolling resistance of rubber composites, and improving the dynamic and static mechanical properties of rubber composites. Tao Zaishan et al. proposed a method in patent CN112778582B, modifying silica with alkyl alkoxysilane polysulfide. The modified silica has both hydrophilic and lipophilic properties, which prevents the agglomeration tendency of silica and improves the compatibility of silica with rubber latex. Wang Wanxing et al. proposed a polyamine dispersant having polar amino functional groups and non-polar alkyl functional groups in patent CN108948467B, which can improve the dispersion of silica in rubber and the hysteresis performance of vulcanized rubber. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a modified white carbon black and a preparation method and application thereof, by means of the interaction of polymers, the compatibility of white carbon black and styrene-butadiene rubber is improved, and the mechanical properties of the composite material are effectively improved.

[0005] The invention provides a modified white carbon black, wherein the modified white carbon black is obtained by modifying a styrene-alpha-methylstyrene copolymer.

[0006] The present invention also provides a method for preparing modified white carbon black, comprising the following steps:

[0007] (1) adding white carbon black into mixed acid for carboxylation treatment to obtain carboxylated white carbon black;

[0008] (2) mixing the carboxylated silica obtained in step (1) with thionyl chloride to obtain acylated silica;

[0009] (3) The acylated silica obtained in step (2) is mixed with a styrene-α-methylstyrene copolymer, and the mixture is stirred for reaction to obtain modified silica.

[0010] Preferably, the mixed acid in step (1) is concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 1:1.

[0011] Preferably, the mass ratio of white carbon black to mixed acid in step (1) is 1:20-1:50.

[0012] Preferably, the carboxylation treatment temperature in step (1) is 60-100° C. and the time is 1-3 h.

[0013] Preferably, the mass ratio of carboxylated white carbon black to thionyl chloride in step (2) is 1:5-1:15.

[0014] Preferably, the reaction temperature in step (2) is 60-100° C., and the reaction time is 1-3 h.

[0015] Preferably, the molecular weight Mn of the styrene-α-methylstyrene copolymer in step (3) is 600-800, and the molecular weight distribution D is 1.5-2.5.

[0016] Preferably, one end of the styrene-α-methylstyrene copolymer in step (3) is a hydroxyl functional group.

[0017] Preferably, the mass ratio of the acylated silica to the styrene-α-methylstyrene copolymer in step (3) is 1:2-1:5.

[0018] Preferably, the reaction temperature in step (3) is 80-100° C., and the reaction time is 10-30 min.

[0019] The invention also provides an application of modified white carbon black in preparing styrene-butadiene rubber composite materials.

[0020] Furthermore, the styrene-butadiene rubber composite material is obtained by mixing white carbon black, styrene-butadiene rubber and other rubber modification additives.

[0021] Preferably, the other rubber processing aids include vulcanizing agents, vulcanization accelerators, and plasticizers.

[0022] Preferably, the vulcanizing agent is sulfur.

[0023] Preferably, the vulcanization accelerator is accelerator diphenylguanidine D and accelerator NS in a mass ratio of 1:1.

[0024] The plasticizer is stearic acid.

[0025] Preferably, the styrene-butadiene rubber composite material comprises the following components: by mass, styrene-butadiene rubber: 100 parts, modified silica: 1-20 parts, vulcanizing agent: 1-5 parts, vulcanization accelerator: 0.2-1.5 parts, and plasticizer: 1-10 parts.

[0026] The preparation method of the styrene-butadiene rubber composite material is carried out according to a conventional process.

[0027] Beneficial Effects

[0028] The present invention utilizes the interaction of polymers to partially replace the hydrophilic groups on the surface with lipophilic alkyl groups, thereby improving the compatibility of white carbon black with styrene-butadiene rubber and effectively improving the mechanical properties of the composite material. In addition, the modified white carbon black is used as an additive for rubber composite materials, which can significantly improve the toughness of the rubber, increase the elongation at break, and at the same time improve the anti-slip ability of the rubber products, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure shows the dynamic mechanical properties comparison between the embodiment and the comparative example. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0031] Example 1

[0032] (1) 20 g of white carbon black was mixed with 500 g of mixed acid (concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 1:1), stirred at 80° C. for 2.5 h, and after sufficient stirring, diluted with deionized water, filtered under reduced pressure, and the solid was dried to obtain carboxylated white carbon black.

[0033] (2) 10 g of carboxylated silica was mixed with 100 g of thionyl chloride, stirred at 100° C. for 2 h, filtered, washed with ether, and dried to obtain acylated silica.

[0034] (3) Take 50 g of the terminal hydroxyl-modified styrene-α-methylstyrene copolymer, heat it to 100° C. to melt it, and then mix it with 25 g of acylated silica and stir it. The mixture is reacted for 15 minutes to obtain modified silica.

[0035] Styrene-butadiene rubber, modified white carbon black, and stearic acid were mixed in an internal mixer, the temperature was set to 85°C, the speed was set to 40r / min, sulfur and vulcanization accelerator (accelerator diphenylguanidine D and accelerator NS in a mass ratio of 1:1) were added after cooling, and the mixture was placed in an open mixer for vulcanization treatment, and a styrene-butadiene rubber composite material was obtained after uniform mixing; wherein the mass ratio of styrene-butadiene rubber, modified white carbon black, sulfur, vulcanization accelerator, and stearic acid was 100:20:2:1:3. The obtained product was subjected to performance testing.

[0036] Example 2

[0037] (1) 20 g of white carbon black and 800 g of mixed acid (concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 1:1) were mixed, stirred at 100° C. for 3 h, and then diluted with deionized water after sufficient stirring. The mixture was then filtered under reduced pressure and the solid was dried to obtain carboxylated white carbon black.

[0038] (2) 10 g of carboxylated silica was mixed with 150 g of thionyl chloride, stirred at 80° C. for 1.5 h, filtered, washed with ether, and dried to obtain acylated silica.

[0039] (3) Take 50 g of the terminal hydroxyl-modified styrene-α-methylstyrene copolymer, heat it to 100° C. to melt it, and then mix it with 20 g of acylated silica and stir it. The mixture is reacted for 10 minutes to obtain modified silica.

[0040] Styrene-butadiene rubber, modified white carbon black, and stearic acid were mixed in an internal mixer, the temperature was set to 85°C, the speed was set to 40r / min, sulfur and vulcanization accelerator (accelerator diphenylguanidine D and accelerator NS in a mass ratio of 1:1) were added after cooling, and the mixture was placed in an open mixer for vulcanization treatment, and a styrene-butadiene rubber composite material was obtained after uniform mixing; wherein the mass ratio of styrene-butadiene rubber, modified white carbon black, sulfur, vulcanization accelerator, and stearic acid was 100:20:2:1:3. The obtained product was subjected to performance testing.

[0041] Comparative Example 1

[0042] The ungrafted white carbon black, styrene-butadiene rubber and stearic acid were mixed in an internal mixer at a temperature of 85°C and a speed of 40 r / min. After cooling, sulfur and a vulcanization accelerator were added, and the mixture was vulcanized in an open mixer. After mixing evenly, a styrene-butadiene rubber composite material was obtained. The mass ratio of styrene-butadiene rubber, white carbon black, vulcanizing agent, vulcanization accelerator and plasticizer was 100:20:2:1:3. The obtained product was tested for performance.

[0043] Comparative Example 2

[0044] Ungrafted white carbon black, styrene-butadiene rubber, styrene-α-methylstyrene copolymer and stearic acid are placed in an internal mixer for mixing, the temperature is set to 85°C, the speed is set to 40r / min, sulfur and vulcanization accelerator are added after cooling, and the mixture is placed in an open mixer for vulcanization treatment. After mixing evenly, a styrene-butadiene rubber composite material is obtained; wherein the mass ratio of styrene-butadiene rubber, white carbon black, vulcanizer, vulcanization accelerator, plasticizer and styrene-α-methylstyrene copolymer is 100:10:2:1:3:10.

[0045] Test method:

[0046] Mechanical property test: Shore hardness was tested using an XY-1 rubber hardness tester according to the method described in GB / T531.1-2008; tensile strength, elongation at break and tensile stress at break were tested using a universal testing machine according to the method described in GB / T528-2009.

[0047] Dynamic mechanical properties test: dynamic mechanical analyzer was used for analysis, and the test conditions were as follows: temperature: -60℃-100℃; heating rate 3℃ / min; frequency 10Hz.

[0048] Table 1 Comparison of mechanical properties of each embodiment and comparative example

[0049] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Tensile strength / MPa 15.7 16.2 13.3 14.9 100% tensile stress / MPa 1.9 1.8 2.6 2.2 300% constant tensile stress / MPa 8.3 7.8 11.3 9.4 Elongation at break / % 482 467 338 434 Shore hardness / degree 65 65 63 64

[0050] The data in Table 1 show that the addition of styrene-α-methylstyrene copolymer significantly improves the elongation at break and tensile strength of the rubber. This is because the addition of the polymer improves the dispersion of inorganic fillers such as silica, reduces stress concentration, and thus improves the toughness of the rubber; and the addition of the polymer grafted onto silica further strengthens this improvement trend.

[0051] Studies have shown that the tanδ value at 0°C corresponds to the anti-slip performance of the rubber compound. Figure 1 It can be seen from the data that the anti-skid performance of the rubber compound with the addition of styrene-α-methylstyrene copolymer is significantly better than that of the rubber compound without the addition of styrene-α-methylstyrene copolymer; if the styrene-α-methylstyrene copolymer is grafted onto silica for processing, the anti-skid performance can be further improved.

Claims

1. A modified white carbon black, characterized in that: The modified white carbon black is obtained by modifying a styrene-alpha-methylstyrene copolymer.

2. A method for preparing modified white carbon black, comprising the following steps: (1) adding white carbon black into mixed acid for carboxylation treatment to obtain carboxylated white carbon black; (2) mixing the carboxylated silica obtained in step (1) with thionyl chloride to obtain acylated silica; (3) The acylated silica obtained in step (2) is mixed with a styrene-α-methylstyrene copolymer, and the mixture is stirred for reaction to obtain modified silica.

3. The preparation method according to claim 2, characterized in that: The mixed acid in step (1) is concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 1:1; the mass ratio of white carbon black to the mixed acid is 1:20-1:

50.

4. The preparation method according to claim 2, characterized in that: The carboxylation treatment temperature in step (1) is 60-100° C. and the time is 1-3 hours.

5. The preparation method according to claim 2, characterized in that: The mass ratio of carboxylated white carbon black to thionyl chloride in the step (2) is 1:5-1:

15.

6. The preparation method according to claim 2, characterized in that: The reaction temperature in step (2) is 60-100° C., and the reaction time is 1-3 h.

7. The preparation method according to claim 2, characterized in that: The mass ratio of the acylated white carbon black to the styrene-α-methylstyrene copolymer in the step (3) is 1:2-1:

5.

8. The preparation method according to claim 2, characterized in that: The reaction temperature in step (3) is 80-100° C., and the reaction time is 10-30 min.

9. Use of the modified silica as claimed in claim 1 in preparing styrene-butadiene rubber composite materials.

10. The use according to claim 9, characterized in that: The styrene-butadiene rubber composite material is obtained by mixing white carbon black, styrene-butadiene rubber and other rubber modification additives.

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