阅读说明：本技术 以稻壳为原料生产塑料增强剂的方法 (Method for producing plastic 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塑料增强剂的方法,以甲基丙烯酸甲酯、稻壳粉和引发剂、阻燃剂为原料发生聚合反应,得到聚甲基丙烯酸甲酯包覆于稻壳粉的内外表面,得到聚甲基丙烯酸甲酯改性稻壳粉,干燥后即为塑料增强剂。本发明的塑料增强剂无毒、无臭、无污染,原料价格便宜,具有与聚合物较优的黏合性和亲和性以及较低的密度；具备良好的尺寸稳定性、耐磨、耐热性以及优异的防水性能。(The invention discloses a method for producing a plastic reinforcing agent by using rice hulls as raw materials, which comprises the steps of carrying out polymerization reaction by using methyl methacrylate, rice hull powder, an initiator and a flame retardant as raw materials to obtain polymethyl methacrylate coated on the inner surface and the outer surface of the rice hull powder to obtain polymethyl methacrylate modified rice hull powder, and drying to obtain the plastic reinforcing agent. The plastic reinforcing agent is nontoxic, odorless and pollution-free, has cheap raw materials, and has better adhesiveness and affinity with polymers and lower density; has good dimensional stability, wear resistance, heat resistance and excellent waterproof performance.)

1. A method for producing a plastic reinforcing agent by using rice hulls as raw materials is characterized by comprising the following steps: the method comprises the following steps:

(1) removing impurities from the rice hulls, putting the rice hulls into a sealed oven at 600-700 ℃, and performing high-temperature sintering carbonization treatment for 1-2 hours to obtain rice hull carbon;

(2) putting the rice husk carbon into a steam environment at 170-200 ℃ for activation treatment for 3-5 h;

(3) grinding the activated rice hull carbon by using grinding equipment until the particle size is 20-50 microns to obtain rice hull carbon powder;

(4) soaking the rice hull carbon powder in a sulfuric acid aqueous solution for 30-60 min, then soaking in a hydrochloric acid aqueous solution for 30-60 min, filtering to dry, taking filter residue, and drying at 70-80 ℃ to obtain soaked rice hull carbon powder for later use;

(5) adding the soaked rice hull carbon powder into an initiator, a flame retardant and methyl methacrylate, uniformly mixing, and carrying out microwave polymerization to obtain polymethyl methacrylate modified rice hull powder; drying to obtain the plastic reinforcing agent.

2. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: the mass concentration of the sulfuric acid aqueous solution in the step (4) is 20-28%.

3. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: the mass concentration of the hydrochloric acid aqueous solution in the step (4) is 22-30%.

4. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: the initiator in the step (5) is one of azobisisobutyronitrile, azobisisoheptonitrile, sodium persulfate, ammonium persulfate and tert-butyl peroxybenzoate.

5. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: and (5) the flame retardant is one or two of magnesium hydroxide powder or titanium dioxide.

6. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: and (5) adding the initiator in an amount of 0.5-2% of the weight of the soaked rice hull carbon powder.

7. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: and (3) adding the methyl methacrylate in the step (5) in an amount of 2-10% of the weight of the soaked rice hull carbon powder.

8. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: the parameters of the microwave polymerization in the step (5) are as follows: the frequency is 50-250 GHz, the temperature is 75-85 ℃, and the time is 10-20 min.

9. The method for producing the plastic reinforcing agent by using the rice hulls as the raw material according to claim 1, characterized in that: the drying conditions in the step (5) are as follows: the temperature is 80-100 ℃, and the time is 20-50 min.

Technical Field

The invention relates to the technical field of plastic reinforcing agents, in particular to a method for producing a plastic 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 husk is 5-10 mm long, 2.5-5 mm thick and 23-30 um thick, and the color of the rice husk is dark yellowGolden yellow, yellow brown and dark red, etc. The bulk density of the rice husk 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. Rice hulls have good toughness, porosity, low density, and a rough texture, which determine some particular uses and applications in industry. 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 plastic reinforcing agent is a substance which is added into the resin, can be tightly combined with the resin and can obviously improve the mechanical property of the product. The plastic reinforcing agent is required to have the following characteristics: (1) chemically inert; (2) water resistance, chemical resistance, weather resistance, heat resistance, and the like; (3) the physical properties are not reduced; (4) can be filled in large quantity; (5) the relative density is small; (6) it is cheap. The filler is very complex in its properties and is not easily distinguishable when used in plastics.

Disclosure of Invention

The invention aims to provide a method for producing a plastic reinforcing agent by using rice husks as raw materials, which can improve the overall performance of plastics and prolong the service life of the plastics. The plastic reinforcing agent is nontoxic, odorless and pollution-free, and has excellent adhesiveness and affinity with polymers and lower density; has good dimensional stability, wear resistance, heat resistance and excellent waterproof performance.

The invention is realized by the following technical scheme:

the method for producing the plastic reinforcing agent by using the rice hulls as the raw materials comprises the following steps:

(1) removing impurities from the rice hulls, putting the rice hulls into a sealed oven at 600-700 ℃, and performing high-temperature sintering carbonization treatment for 1-2 hours to obtain rice hull carbon;

(2) putting the rice husk carbon into a steam environment at 170-200 ℃ for activation treatment for 3-5 h;

(3) grinding the activated rice hull carbon by using grinding equipment until the particle size is 20-50 microns to obtain rice hull carbon powder;

(4) soaking the rice hull carbon powder in a sulfuric acid aqueous solution for 30-60 min, then soaking in a hydrochloric acid aqueous solution for 30-60 min, filtering to dry, taking filter residue, and drying at 70-80 ℃ to obtain soaked rice hull carbon powder for later use;

(5) adding the soaked rice hull carbon powder into an initiator, a flame retardant and methyl methacrylate, uniformly mixing, and carrying out microwave polymerization to obtain polymethyl methacrylate modified rice hull powder; drying to obtain the plastic reinforcing agent.

Specifically, the mass concentration of the sulfuric acid aqueous solution in the step (4) is 20-28%.

The mass concentration of the hydrochloric acid aqueous solution in the step (4) is 22-30%.

Preferably, the initiator in the step (5) is one of azobisisobutyronitrile, azobisisoheptonitrile, sodium persulfate, ammonium persulfate and tert-butyl peroxybenzoate. The addition amount of the initiator is 0.5-2% of the weight of the soaked rice hull carbon powder.

And (5) the flame retardant is one or two of magnesium hydroxide powder or titanium dioxide. The addition amount of the flame retardant is 0.2-1.2% of the weight of the soaked rice hull carbon powder.

And (3) adding the methyl methacrylate in the step (5) in an amount of 2-10% of the weight of the soaked rice hull carbon powder.

Preferably, the parameters of the microwave polymerization in the step (5) are as follows: the frequency is 50-250 GHz, the temperature is 75-85 ℃, and the time is 10-20 min.

The drying conditions in the step (5) are as follows: the temperature is 80-100 ℃, and the time is 20-50 min.

According to the invention, methyl methacrylate, rice hull powder, an initiator and a flame retardant are used as raw materials, and after mixing, a polymerization reaction is carried out, in the mixing process, monomer methyl methacrylate is distributed in micropores of the rice hull powder and on the outer surface of the rice hull powder, and then the polymethyl methacrylate is obtained through the polymerization reaction, and is coated on the inner surface and the outer surface of the rice hull powder, namely the rice hull powder is coated inside, so that the water absorption of the modified rice hull powder is reduced, and the modified rice hull powder has excellent waterproof performance. In addition, because the polymethyl methacrylate has better compatibility with the high-density polyethylene, the rice hull powder modified by the methyl methacrylate can be uniformly mixed with the high-density polyethylene, and has better adhesiveness and affinity with the polymer.

The titanium dioxide powder is titanium dioxide powder, and the titanium dioxide has higher melting point and good heat resistance, can enhance the mechanical strength and adhesive force of plastics, prevent cracks, prevent ultraviolet rays and moisture from permeating, prolong the service life of a paint film, lighten the color of the plastics and have better reflection and heat insulation properties.

The magnesium hydroxide is a novel filling type flame retardant, releases bound water when heated and decomposed, absorbs a large amount of latent heat to reduce the surface temperature of a synthetic material filled with the magnesium hydroxide in flame, and has the effects of inhibiting the decomposition of a polymer and cooling generated combustible gas. The magnesium oxide generated by decomposition is a good refractory material, and can also help to improve the fire resistance of the synthetic material, and the water vapor emitted by the magnesium oxide can also be used as a smoke suppressant. Magnesium hydroxide is a well-known excellent flame retardant with triple functions of flame retardance, smoke suppression and filling in the rubber and plastic industry.

The invention has the beneficial effects that:

1. the plastic reinforcing agent can improve the processing performance of plastics, improve the physical and chemical properties, increase the volume and reduce the production cost of plastics.

2. The plastic reinforcing agent takes methyl methacrylate, rice hull powder, an initiator and a flame retardant as raw materials, and the polymethyl methacrylate modified rice hull powder is prepared by polymerization reaction, and has excellent adhesion and affinity with a polymer and lower density.

3. The plastic reinforcing agent of the invention is added with magnesium hydroxide powder or titanium dioxide as a flame retardant, and the titanium dioxide can enhance the mechanical strength and adhesive force of plastics, prevent cracks, prevent ultraviolet rays and moisture from permeating, prolong the service life of a paint film and have better reflection and heat insulation properties. Magnesium hydroxide releases bound water when decomposed by heat, absorbs a large amount of latent heat to lower the surface temperature of the synthetic material filled with the magnesium hydroxide in the flame, and has the effects of inhibiting the decomposition of polymers and cooling the generated combustible gas. The plastic reinforcing agent provided by the invention is added into a plastic product, so that the plastic reinforcing agent has good dimensional stability, wear resistance and heat resistance, and can improve the thermal deformation temperature and reduce the linear expansion coefficient.

4. The plastic reinforcing agent of the invention has no toxicity, odor and pollution, and the raw materials are cheap.

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.