A method for preparing a modified white carbon black for rubber reinforcement

Abstract

The application discloses a preparation method of modified white carbon black for rubber reinforcing agent, and specifically comprises the following steps: S1: rice husks are soaked in dilute hydrochloric acid for 18-24 hours, and then the rice husks are cleaned until the pH value is 7, and the pretreated rice husks are dried; S2: the pretreated rice husks are burned in a combustion furnace for 4-5 hours to obtain rice husk ash; S3: the rice husk ash is mixed in an active water solution, and sodium hydroxide is added to obtain a sodium metasilicate water solution; S4: the pH value of the sodium metasilicate water solution is controlled to be 8-9, and then a certain concentration of sulfuric acid is added to carry out a precipitation reaction under certain reaction conditions; the reactants are cleaned, acidified, aged, filtered, dried and crushed to obtain amorphous nanometer silicon oxide; and S5: the amorphous nanometer silicon oxide is uniformly mixed with a surface additive at a certain proportion to obtain a final product. The amorphous silicon oxide is prepared from rice husks by using an improved chemical precipitation method, and the amorphous silicon oxide is premixed with a surface additive, so that the reinforcing performance of the white carbon black on rubber is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rubber auxiliaries, and particularly relates to a preparation method of modified white carbon black for rubber reinforcing agent. BACKGROUND

[0002] Raw rubber, also known as rubber, is an important natural product. It has a wide range of applications, from automobile tires to medical supplies, and cannot exist without it. Generally, raw rubber is a linear macromolecular chain with poor mechanical properties. In order to obtain rubber products that meet various performance requirements, reinforcing agents are usually used. The interaction between the reinforcing agent and the rubber is important for the reinforcing performance of the rubber. Many properties of rubber such as wear resistance, elasticity, strength and dynamic performance are related to the reinforcing effect of the reinforcing agent and the rubber. These properties are of great significance to the service life of rubber products, especially tires.

[0003] White carbon black is one of the most important reinforcing agents for rubber. The vulcanized rubber reinforced by white carbon black has high tear strength, low dynamic heat generation of vulcanized rubber, good dynamic fatigue performance, and can improve the adhesion strength of rubber and metal and cord. However, due to the strong polarity and hydrophilicity of the surface of white carbon black, its compatibility with hydrocarbon rubber molecules is poor. If a large amount of white carbon black is filled in rubber, the reinforcing effect such as tensile strength, wear resistance and other properties will decrease. SUMMARY

[0004] In order to solve the problems in the prior art, the present application provides a preparation method of modified white carbon black for rubber reinforcing agent, which uses rice husk as raw material and adopts an improved chemical precipitation method to obtain amorphous silicon oxide, and premixes the amorphous silicon oxide with a surface additive, thereby improving the reinforcing performance of white carbon black for rubber.

[0005] The technical scheme mainly adopted in the present application is as follows:

[0006] A preparation method of modified white carbon black for rubber reinforcing, the specific steps are as follows:

[0007] S1: soaking the rice husk in dilute hydrochloric acid for 18-24 hours, then washing the rice husk to pH 7, and drying to obtain pretreated rice husk;

[0008] S2: placing the pretreated rice husk in a combustion furnace and burning for 4-5 hours to obtain rice husk ash;

[0009] S3: mixing the rice husk ash in an active water solution, and adding sodium hydroxide in the active water solution to obtain a certain concentration of sodium metasilicate aqueous solution;

[0010] S4: the pH value of the sodium metasilicate aqueous solution is controlled to be 8-9, then a certain concentration of sulfuric acid is added to carry out a precipitation reaction under certain reaction conditions, and the reactants are cleaned, acidified, aged, filtered, dried and crushed to obtain amorphous nano silicon oxide;

[0011] S5: the amorphous nano silicon oxide is uniformly mixed with a surface additive in a certain proportion to obtain a final product.

[0012] Preferably, in S1, the concentration of the dilute hydrochloric acid is 0.7-1.2 mol / L.

[0013] Preferably, in S2, the combustion temperature is controlled to be 650-700℃.

[0014] Preferably, in S3, the active aqueous solution is an anionic active agent aqueous solution.

[0015] Preferably, in S3, the anionic active agent is one or a mixture of two of sodium hexadecyl sulfonate, sodium dodecyl benzene sulfonate and sodium polyacrylate, and the amount of the anionic active agent is 3%-8% of the mass of the rice husk ash.

[0016] Preferably, in S3, the concentration of the sodium metasilicate solution is 0.25-0.45 mol / L.

[0017] Preferably, in S4, the concentration of the sulfuric acid is 0.35-0.55 mol / L.

[0018] Preferably, in S4, the time of the precipitation reaction is 40-60 min, and the reaction temperature is 55-65℃.

[0019] Preferably, in S5, the amount of the surface additive added is 5%-10% of the mass of the amorphous nano silicon oxide.

[0020] Preferably, in S5, the surface additive is one or a mixture of more than one of an amine type or an alcohol type surface additive.

[0021] Beneficial effects: the application provides a preparation method of modified white carbon black for rubber reinforcing agent, and has the following advantages compared with the prior art:

[0022] (1) the amorphous silicon oxide prepared by the improved chemical precipitation method with rice husk as raw material has the organic component remaining on the surface of the white carbon black extracted from the rice husk ash, can effectively improve the compatibility with rubber compared with conventional white carbon black, is uniformly dispersed in the rubber system in a nanoscale size, has good reinforcing effect, and has good economic value and social significance.

[0023] (2) In the present application, the anionic active agent is used to treat the rice husk ash solution in the preparation process of amorphous silicon dioxide, so that the impurities attached to the skeleton of the rice husk ash can be further removed, and the whiteness and silicon dioxide content of the product can be improved.

[0024] (3) In the present application, in order to avoid the adsorption of the accelerator and the antioxidant added in the rubber mixing process by the white carbon black, causing the delayed vulcanization phenomenon, an amine and an alcohol surface additive are premixed in the white carbon black. The substance is preferentially adsorbed on the surface of the white carbon black, reducing the adsorption of the accelerator by the white carbon black. Embodiment

[0025] In order to make the person skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application. Embodiment

[0026] A preparation method of modified white carbon black for rubber reinforcing agent, the specific steps are as follows:

[0027] S1: soaking the rice husk in dilute hydrochloric acid (1.2 mol / L) for 24 hours, then washing the rice husk to pH 7, and drying to obtain the pretreated rice husk;

[0028] S2: placing the pretreated rice husk into a combustion furnace and burning at 650℃ for 4.5 hours to obtain rice husk ash;

[0029] S3: mixing the rice husk ash in an active water solution (sodium hexadecyl sulfonate and sodium polyacrylate with a mass ratio of 1:1), and adding sodium hydroxide in the active water solution to obtain a 0.25 mol / L sodium metasilicate solution;

[0030] S4: controlling the pH value of the sodium metasilicate solution to be 8, then adding 0.4 mol / L sulfuric acid at 60℃ for precipitation reaction for 60 minutes, and then washing, acidifying, aging, filtering, drying and crushing the reaction product to obtain amorphous nano silicon dioxide;

[0031] S5: uniformly mixing the amorphous nano silicon dioxide with a surface additive (polyethylene glycol-4000) in a certain proportion to obtain the final product, wherein the addition amount of the surface additive is 5% of the mass of the amorphous nano silicon dioxide. Embodiment

[0032] A preparation method of modified white carbon black for rubber reinforcing agent, the specific steps are as follows:

[0033] S1: soaking rice husk in dilute hydrochloric acid (1.2 mol / L) for 24 h, then washing the rice husk to pH 7, and drying to obtain pretreated rice husk;

[0034] S2: placing the pretreated rice husk into a combustion furnace and burning at 650℃ for 4.5 h to obtain rice husk ash;

[0035] S3: mixing the rice husk ash in an active water solution (sodium dodecyl benzene sulfonate and sodium polyacrylate at a mass ratio of 1:1), and adding sodium hydroxide in the active water solution to obtain a 0.3 mol / L sodium metasilicate aqueous solution;

[0036] S4: controlling the pH value of the sodium metasilicate aqueous solution to be 8, then adding 0.5 mol / L sulfuric acid to perform a precipitation reaction at 60℃ for 60 min, and obtaining amorphous nano silicon oxide by washing, acidifying, aging, filtering, drying, and crushing the reaction product;

[0037] S5: uniformly mixing the amorphous nano silicon oxide with a surface additive (polyethylene glycol-4000) at a certain ratio to obtain a final product, wherein the addition amount of the surface additive is 8% of the mass of the amorphous nano silicon oxide. Embodiment

[0038] A preparation method of modified white carbon black for rubber reinforcing agent, the specific steps are as follows:

[0039] S1: soaking rice husk in dilute hydrochloric acid (1.2 mol / L) for 24 h, then washing the rice husk to pH 7, and drying to obtain pretreated rice husk;

[0040] S2: placing the pretreated rice husk into a combustion furnace and burning at 650℃ for 4.5 h to obtain rice husk ash;

[0041] S3: mixing the rice husk ash in an active water solution (sodium dodecyl benzene sulfonate and sodium polyacrylate at a mass ratio of 1:1), and adding sodium hydroxide in the active water solution to obtain a 0.3 mol / L sodium metasilicate aqueous solution;

[0042] S4: controlling the pH value of the sodium metasilicate aqueous solution to be 8, then adding 0.5 mol / L sulfuric acid to perform a precipitation reaction at 60℃ for 60 min, and obtaining amorphous nano silicon oxide by washing, acidifying, aging, filtering, drying, and crushing the reaction product;

[0043] S5: uniformly mixing the amorphous nano silicon oxide with a surface additive (polyethylene glycol-4000) at a certain ratio to obtain a final product, wherein the addition amount of the surface additive is 8% of the mass of the amorphous nano silicon oxide.

[0044] Test formula (by mass fraction): NR (Nanjing Youbaolong Rubber and Plastic Co., Ltd.) 100; carbon black N330 20; zinc oxide 4; stearin 2; silane coupling agent KH-550 2; coumarone 3; antioxidant 4010 2; sulfur 2.5, vulcanization accelerator TBBS 1.5; accelerator TMTD 0.2, white carbon black 20.

[0045] The white carbon black prepared in Example 1, Example 2, Example 3 and the common white carbon black (A-200, Duwei Chemical) of the comparative example were respectively applied to the above test formula, and a three-stage mixing process was used for mixing, and finally a mixed rubber was obtained. According to the national standard, the reinforcement performance of the mixed rubber was tested and compared, and the test results are shown in Table 1.

[0046] Table 1 is the reinforcement performance test results of each sample

[0047]

[0048] From Table 1, compared with the comparative example, the modulus, tensile strength and tear strength of the rubber of Examples 1-3 are improved, and the rubber has good reinforcement performance, wear resistance and hardness, which is basically the same as the comparative example. This is because the amorphous silicon oxide prepared by the improved chemical precipitation method, and the organic matter component is left on the surface of the white carbon black extracted from the rice husk ash in the present example 1-3, which can effectively improve the compatibility with the rubber, and uniformly dispersed in the rubber system in nanoscale size, and has good reinforcement effect.

[0049] Compared with the comparative example, the Mooney scorch time of the rubber of Examples 1-3 is shortened, the Mooney viscosity is increased, and the vulcanization rate is decreased. This is because the white carbon black particles have high specific surface energy, which can adsorb many small organic molecules, such as adsorbing the accelerator, antioxidant and other related additives added in the rubber mixing process, so that the content of the related vulcanizing aid is reduced, which causes the delayed vulcanization phenomenon, and affects the vulcanization effect. Therefore, in order to produce delayed vulcanization phenomenon, amine or alcohol surface agent (such as polyethylene glycol-4000) is pre-mixed in the amorphous white carbon black in Examples 1-3, so that it can be preferentially adsorbed on the surface of the white carbon black during mixing, and the adsorption of the white carbon black on the vulcanizing aid is weakened, thereby improving the vulcanization performance of the rubber.

[0050] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should be considered as the protection scope of the present application.

Claims

1. A method for preparing a modified white carbon black for rubber reinforcement, characterized by, The specific steps are as follows: S1: soaking the rice husk in dilute hydrochloric acid with a concentration of 0.7-1.2 mol / L for 18-24 h, then washing the rice husk to pH 7, and drying to obtain the pretreated rice husk; S2: placing the pretreated rice husk in a combustion furnace and combusting at 650-700℃ for 4-5 h to obtain rice husk ash; S3: mixing the rice husk ash in an anionic active agent aqueous solution, and adding sodium hydroxide in the active aqueous solution to obtain a sodium metasilicate aqueous solution with a concentration of 0.25-0.45 mol / L, wherein the amount of the anionic active agent is 3%-8% of the mass of the rice husk ash; S4: controlling the pH value of the sodium metasilicate aqueous solution to be 8-9, then adding sulfuric acid with a concentration of 0.35-0.55 mol / L, and performing a precipitation reaction at 55-65℃ for 40-60 min, and then washing, acidifying, aging, filtering, drying, and crushing the reactants to obtain amorphous nanosilica; S5: uniformly mixing the amorphous nanosilica with a surface aid at 5%-10% of the mass of the amorphous nanosilica to obtain the final product.

2. The production method according to claim 1, characterized by, The anionic active agent is one or a mixture of two of sodium hexadecyl sulfonate, sodium dodecyl benzene sulfonate, and sodium polyacrylate.

3. The preparation method according to claim 1, characterized in that, The surface aid is one or a mixture of two or more of amine or alcohol surface aids.

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