阅读说明：本技术 以稻壳为原料生产橡胶补强剂的方法 (Method for producing rubber reinforcing agent by using rice husk as raw material ) 是由 白伟锋 何青 于 2019-10-16 设计创作，主要内容包括：本发明公开了一种以稻壳为原料生产橡胶补强剂的方法,以稻壳为原料首先制备成稻壳灰,然后加碱液制备成水玻璃,再加入酸液制备成稻壳白炭黑,最后将稻壳白炭黑进行改性,得到橡胶补强机。本发明的橡胶补强剂,采用两次改性的方法,先经过硅烷偶联剂KH-550进行一次改性,再经过3,5-二叔丁基-4-羟基苯乙酸进行二次改性,通过氨基与羧基反应连接到改性白炭黑的表面,不仅可以提高白炭黑在天然橡胶中的分散性和相容性,还能使其具有一定的防老功能。(The invention discloses a method for producing a rubber reinforcing agent by using rice hulls as raw materials. The rubber reinforcing agent disclosed by the invention is prepared by a twice modification method, and is firstly subjected to once modification through a silane coupling agent KH-550, then subjected to twice modification through 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid, and connected to the surface of modified white carbon black through the reaction of amino and carboxyl, so that the dispersibility and compatibility of the white carbon black in natural rubber can be improved, and the white carbon black has a certain anti-aging function.)

1. The method for producing the rubber reinforcing agent by using the rice husk as the raw material is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing rice hull ash: removing impurities from the rice hulls, and then burning the rice hulls for 5-6 hours at constant temperature at 500-780 ℃ under an anoxic condition to obtain incompletely burnt rice hull ash;

(2) preparing water glass: adding sodium hydroxide solution which is 2-10 times of the weight of the rice hull ash into the rice hull ash obtained in the step (1), uniformly stirring, heating to 170-220 ℃, pressurizing to 0.6-0.8 MPa, reacting for 2-4 h, and filtering to obtain liquid, namely water glass;

(3) preparing white carbon black: putting the water glass obtained in the step (2) into a reaction kettle, introducing steam to keep the temperature at 60-80 ℃, slowly introducing a sulfuric acid solution with the mass concentration of 5-10%, reacting for 2-4 hours, and adding continuous ultrasonic treatment in the reaction; after the reaction is finished, heating to 85-90 ℃, adding sodium citrate, uniformly stirring, standing for 1-2 h, centrifuging, filtering to obtain filter residue, washing with water to reach pH of 6-7, and drying to obtain rice hull white carbon black for later use;

(4) Modification of rice hull white carbon black: adding the rice hull white carbon black obtained in the step (3) into an ethanol water solution with the mass fraction of 80-90%, performing ultrasonic oscillation for 30-40 min to uniformly mix the rice hull white carbon black, heating to 60-70 ℃, adding a coupling agent, and reacting for 2-4 h; heating to 90-100 ℃, adding a modifier, and reacting for 3-4 h; filtering to obtain filter residue, namely modified white carbon black;

(5) And (4) crushing the modified white carbon black obtained in the step (4) to 1-10 microns, washing the crushed white carbon black for 2-3 times by using absolute ethyl alcohol, and drying the washed white carbon black to obtain the rubber reinforcing agent.

2. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: the addition amount of the sulfuric acid solution in the step (3) is 1-2 times of the volume of the water glass.

3. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: and (4) adding the sodium citrate in the step (3) in an amount of 0.2-0.3% of the weight of the water glass.

4. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: the coupling agent in the step (4) is a silane coupling agent KH550, namely gamma-aminopropyl triethoxysilane.

5. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: the addition amount of the coupling agent is 3-6% of the weight of the rice hull white carbon black.

6. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: the modifier in the step (4) is 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid.

7. a method for producing a rubber reinforcing agent using rice hulls as a raw material according to claim 1, characterized in that: the addition amount of the modifier is 2-8% of the weight of the rice hull white carbon black.

8. a rubber reinforcing agent produced from rice husk as claimed in claim 1, wherein the amount of the rubber reinforcing agent added is 10-25% of the weight of the rubber.

Technical Field

The invention relates to the technical field of rubber reinforcing agents, in particular to a method for producing a rubber reinforcing agent by using rice husks as raw materials.

Background

Rice hulls are also known as rice husks, a layer of husk on the outside of rice. The rice hulls are 5-10 mm long, 2.5-5 mm long and 23-30 um thick, and the color and luster of the rice hulls are dark yellow, golden yellow, yellow brown, brownish red and the like. The stacking density of the rice hulls is 96-160 kg.m^-3after the rice hulls are crushed, the bulk density can reach 384-400 kg^-3. The rice hulls are rich in cellulose, lignin, silica, and have very low fat and protein content. The rice husk has good toughness, porosity, low density and coarse texture, and is determined by the fact thatIndustrial special uses and application areas. The hulls contain approximately 40% crude fiber and approximately 20% pentose polymer.

According to statistics, the annual output of the rice in China currently exceeds one hundred million and eight million tons, which accounts for about one third of the annual output of the whole world and is the first in the world. During rice processing, a large amount of rice hulls are produced, and each ton of rice can produce about 200kg of rice hulls. These hulls are extremely inconvenient to transport due to their low natural bulk density. On the other hand, most rice processing enterprises do not have a reasonable and effective process for utilizing the rice hulls, so that a lot of rice hulls are discarded as agricultural wastes.

For a long time, the comprehensive utilization of rice hulls at home and abroad is widely researched, and a plurality of available ways are obtained. But can really form large-scale production, has few utilization ways for consuming a large amount of rice hulls, or has little economic benefit increment, or has some problems in the aspects of process, technology, quality, environmental pollution and the like. Thus, many places use rice hulls as waste. This not only wastes resources greatly and causes huge economic loss, but also causes great pollution to the environment. The research solves the reasonable utilization of the rice hulls, changes waste into valuable, and is a significant task before the people.

The rubber reinforcing agent is a compounding agent capable of improving the strength of rubber products. The white carbon black is a reinforcing agent which is most applied in the field of rubber industry at present, is a chain dendritic aggregate, mainly comprises amorphous silicon dioxide as a chemical component, contains a large amount of silicon hydroxyl on the surface, is hydrophilic and is easy to agglomerate, so that the compatibility of the white carbon black with a rubber matrix is poor, and the dispersibility of the white carbon black in rubber is poor. In addition, in the vulcanization process of the rubber, the silica white with weakly acidic surface is easy to adsorb compounding agents in the rubber, so that the vulcanization is delayed, the crosslinking density is reduced, and the like, and the reinforcing performance of the rubber is seriously influenced. To solve this problem, it is effective to modify the white carbon black.

disclosure of Invention

Aiming at the technical defects, the invention aims to provide a method for producing a rubber reinforcing agent by using rice husks as raw materials, wherein the rubber reinforcing agent is modified twice by a silane coupling agent KH-550 and 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid, so that the dispersibility and compatibility of white carbon black in natural rubber can be improved, and the white carbon black has a certain anti-aging function.

The invention is realized by the following technical scheme:

The method for producing the rubber reinforcing agent by using the rice husk as the raw material comprises the following steps:

(1) preparing rice hull ash: removing impurities from the rice hulls, and then burning the rice hulls for 5-6 hours at constant temperature at 500-780 ℃ under an anoxic condition to obtain incompletely burnt rice hull ash;

(2) Preparing water glass: adding sodium hydroxide solution which is 2-10 times of the weight of the rice hull ash into the rice hull ash obtained in the step (1), uniformly stirring, heating to 170-220 ℃, pressurizing to 0.6-0.8 MPa, reacting for 2-4 h, and filtering to obtain liquid, namely water glass;

(3) Preparing white carbon black: putting the water glass obtained in the step (2) into a reaction kettle, introducing steam to keep the temperature at 60-80 ℃, slowly introducing a sulfuric acid solution with the mass concentration of 5-10%, reacting for 2-4 hours, and adding continuous ultrasonic treatment in the reaction; after the reaction is finished, heating to 85-90 ℃, adding sodium citrate, uniformly stirring, standing for 1-2 h, centrifuging, filtering to obtain filter residue, washing with water to reach pH of 6-7, and drying to obtain rice hull white carbon black for later use;

(4) Modification of rice hull white carbon black: adding the rice hull white carbon black obtained in the step (3) into an ethanol water solution with the mass fraction of 80-90%, performing ultrasonic oscillation for 30-40 min to uniformly mix the rice hull white carbon black, heating to 60-70 ℃, adding a coupling agent, and reacting for 2-4 h; heating to 90-100 ℃, adding a modifier, and reacting for 3-4 h; filtering to obtain filter residue, namely modified white carbon black;

(5) And (4) crushing the modified white carbon black obtained in the step (4) to 1-10 microns, washing the crushed white carbon black for 2-3 times by using absolute ethyl alcohol, and drying the washed white carbon black to obtain the rubber reinforcing agent.

specifically, the addition amount of the sulfuric acid solution in the step (3) is 1-2 times of the volume of the water glass.

and (4) adding the sodium citrate in the step (3) in an amount of 0.2-0.3% of the weight of the water glass.

The coupling agent in the step (4) is a silane coupling agent KH550, namely gamma-aminopropyl triethoxysilane.

The addition amount of the coupling agent is 3-6% of the weight of the rice hull white carbon black.

The modifier in the step (4) is 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid.

the addition amount of the modifier is 2-8% of the weight of the rice hull white carbon black.

the rubber reinforcing agent produced by using the rice hulls as the raw materials is added in the rubber mixing process, and the adding amount is 10-25% of the weight of rubber liter.

The silane coupling agent KH-550 (gamma-aminopropyltriethoxysilane) is a colorless transparent liquid, and is soluble in water and organic solvents. Hydrolyzing in water to obtain alkaline. The organic polymer/inorganic filler composite is used for coupling organic polymers and inorganic fillers, and can enhance the cohesiveness and improve the mechanical, water-resistant and aging-resistant properties of products. The rice hull white carbon black modified by the silane coupling agent KH-550 improves the compatibility between the rice hull white carbon black and polymers, increases the interaction between interfaces, and can effectively improve the mechanical properties of rubber polymers.

The rice hull white carbon black modified by the silane coupling agent KH-550 is subjected to secondary modification by 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid and is connected to the surface of the modified white carbon black through the reaction of amino and carboxyl, so that the dispersibility of the white carbon black in natural rubber can be improved, and the white carbon black has a certain anti-aging function.

therefore, the rubber reinforcing agent produced by the invention is added in the rubber mixing process, has good compatibility with an organic medium, can not prevent the aggregation of white carbon black, can improve the dispersibility of the white carbon black in rubber, and has good anti-aging performance.

The invention has the beneficial effects that:

1. the rubber reinforcing agent produced by the invention is added in the rubber mixing process, has good compatibility with an organic medium, can not prevent the aggregation of white carbon black, can improve the dispersibility of the white carbon black in rubber, and has good anti-aging performance.

2. After the rice hull white carbon black is modified by the silane coupling agent KH-550, the compatibility between the rice hull white carbon black and a polymer is improved, the interaction between interfaces is increased, and the mechanical property of a rubber polymer can be effectively improved.

3. The rubber reinforcing agent disclosed by the invention is prepared by a twice modification method, and is firstly subjected to once modification through a silane coupling agent KH-550, then subjected to twice modification through 3, 5-di-tert-butyl-4-hydroxyphenylacetic acid, and connected to the surface of modified white carbon black through the reaction of amino and carboxyl, so that the dispersibility and compatibility of the white carbon black in natural rubber can be improved, and the white carbon black has a certain anti-aging function.

Detailed Description

in order to make the technical solutions and advantages of the present invention clearer, the following describes the technical solutions of the present invention clearly and completely in combination with the embodiments of the present invention.