阅读说明：本技术 一种生物基降解环保袋的制备方法 (Preparation method of bio-based degradable environment-friendly bag ) 是由 沈金良 于 2020-04-21 设计创作，主要内容包括：本发明公开了一种生物基降解环保材料,所述生物基降解环保材料是以聚乙烯和淀粉为原料,通过自在反应体系中加入热塑性聚氨酯,然后用双焊杆挤出机造粒为母料烘干养护而成。该生物基降解环保材料,配制合成科学工艺简单,实验过程中使用到的反应器相对较少,且整个实验过程都是在常压下进行的,原料不会释放出毒性气体和废水。综合考虑风险较小。同时主要原料为淀粉和聚乳酸、聚乙烯,价廉易购,产品有极好的耐水、耐油等性能；有适宜的保质期,不易变质；废弃后极易降解；使用过程中不释放气体和其他物质,采用本发明的材料制成的环保产品,可以使该生物基降生物碳含量达到25%以上。(The invention discloses a bio-based degradable environment-friendly material which is prepared by taking polyethylene and starch as raw materials, adding thermoplastic polyurethane into a reaction system, and then granulating by using a double-welding-rod extruder to obtain a master batch, and drying and maintaining the master batch. The bio-based degradable environment-friendly material is simple in preparation and synthesis scientific process, relatively few reactors are used in the experimental process, the whole experimental process is carried out under normal pressure, and toxic gas and waste water cannot be released from raw materials. The risk is small in comprehensive consideration. Meanwhile, the main raw materials are starch, polylactic acid and polyethylene, the price is low, the raw materials are easily purchased, and the product has excellent water resistance, oil resistance and other properties; has suitable shelf life and is not easy to deteriorate; the waste is easy to degrade; gas and other substances are not released in the using process, and the environment-friendly product prepared from the material can enable the content of the bio-based reduced biochar to reach more than 25%.)

1. A bio-based degradable environment-friendly material is characterized in that: the method specifically comprises the following steps:

s1, mixing 50-60 parts of starch, 10-20 parts of polylactic acid and 15-20 parts of thermoplastic polyurethane for 2 hours, adding 1-2 parts of auxiliary agent into the mixture, and continuously mixing for 1 hour to obtain a modified starch mixture;

s2, heating the modified starch mixture to 110 ℃, adding 5-8 parts of coupling agent into the modified starch mixture, stirring and mixing for 2h, drying, mixing for 1h in a double-roller open mill, and performing crosslinking plasticization between the modified starch mixture and the coupling agent to obtain a modified starch primary compound;

s3, adding 18-25 parts of glycerol into the modified starch primary compound obtained in the step S2, mixing and stirring for 2 hours, fully dispersing and lubricating the mixture, and effectively adjusting the viscosity of the mixture;

and S4, adding 30-40 parts of polyethylene and 1-2 parts of hydrolysis resistant agent into the mixture, uniformly mixing, feeding into a double-welding-rod extruder for granulation, and drying to obtain the polyethylene-polyethylene composite material.

2. The bio-based degradable environment-friendly material as claimed in claim 1, wherein: the coupling agent in the step S2 is an aluminate coupling agent.

3. The bio-based degradable environment-friendly material as claimed in claim 1, wherein: the additives in the step S4 are as follows: ethylene-vinyl acetate copolymer (EVA), Polycaprolactone (PCL) and polyhydroxyalkanoate.

4. The bio-based degradable environment-friendly material as claimed in claim 1, wherein: and the auxiliary agent in the step S1 is light powder or nano silicon dioxide particles.

5. The bio-based degradable environment-friendly material as claimed in claim 1, wherein: and the drying temperature in the step S2 is 60-80 ℃.

Technical Field

The invention belongs to the technical field of environmental protection, and particularly relates to a bio-based degradable environment-friendly material which can replace PE.

Background

The plastic industry is a product industry and an emerging material industry. In recent years, the plastic industry has developed rapidly with the rapid development of the civil economy, particularly the petrochemical industry. The apparent consumption of synthetic resin in 1998 was about 14940 ten thousand tons and that of plastic articles was 1427.6 ten thousand tons. As an important industrial material and a consumption material, the plastic material and the product are widely applied to the fields of industry, agriculture, packaging industry, high technology and various aspects of people's life, and are juxtaposed with steel, wood and cement to form four main supporting column materials. Plays an increasingly important role in promoting the technical progress of national economic reserve departments and meeting the needs of people in life. In recent years, about 400 million tons of plastic for packaging in China, about 120 million tons of plastic packaging waste generated each year when about 30% of disposable plastic packages which are difficult to recycle account for, and about 40 million tons of plastic mulching films are thin (less than 8 μm), so that the plastic mulching films are broken in farmlands after use and contain a large amount of sandy soil, are difficult to recycle, and about 40 million tons of disposable daily sundries and medical supplies which are difficult to recycle. The comprehensive utilization of the various secondary plastic wastes reaches about 200 ten thousand tons. According to the investigation of cities such as Beijing, Shanghai and Tianjin, the mass fraction of the plastic waste in an urban solid waste treatment system (ASW) is about 3-7%, and the volume fraction accounts for 10-20%. The environmental problems caused by the method are increasingly serious, and great attention and strong reverberation are brought to the whole society. For this reason, the government of China has paid great attention to, and countermeasures and measures are being actively studied. The widespread use of plastic products in industry and daily life generates large quantities of plastic waste that is difficult to dispose of, creating a serious environmental hazard. The reduction and solution of the environmental pollution problem of waste plastics have attracted much attention from countries in the world, and the use and development of biodegradable plastics have become one of the important means for solving the problem of "white pollution" in countries.

Starch is fast to regenerate, can be completely biodegraded, and has high environmental friendliness, so that the research on the application of the starch as biodegradable plastic is more and more emphasized. The starch molecules contain more hydrogen bonds and larger intermolecular force, generally contain 15-45% of crystalline components, the glass transition temperature of an amorphous region is very close to the decomposition temperature, and the melting point of a crystalline region is far higher than the decomposition temperature, so that the natural starch does not have plasticity. If some small molecular plasticizers with hydrogen bonds are added into the starch, the plasticizer can partially form hydrogen bonds with the starch, and the density of the hydrogen bonds among the starch molecules is reduced through mechanical isolation, so that the intermolecular force of the starch is reduced, the glass transition temperature and the melting point of the starch molecules are reduced, and the thermoplastic starch can be prepared. Small molecule plasticizers are typically polyols, with glycerol being the most widely used. However, the thermoplastic starch prepared in this way may have a "retrogradation" phenomenon during use, i.e., the starch is recrystallized due to the failure of the plasticizer, and the crystallized starch becomes brittle and loses the use performance, which is an important factor limiting the use performance of the starch. Chemical modification of starch is an important alternative method, and because starch contains a large number of hydroxyl groups in the molecule, reaction with hydroxyl groups such as esterification and the like is one of the common methods for starch modification. In the modified esterified starch, partial hydroxyl is converted into ester groups, the density of the hydroxyl is reduced, the hydrogen bonding effect between chains is weakened, the melting point of a crystal region is reduced, when the melting point is lower than the decomposition temperature, the melting of microcrystals can be realized before decomposition, the starch has real thermoplasticity, and the esterification modification is the effect of chemical bonds, so that the prepared starch plastic does not have the phenomenon of 'regeneration'. In addition, the mechanical property and the water resistance of the starch plastic are poor, so that the application of the starch plastic is limited.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides a bio-based degradable environment-friendly material which is simple to prepare, biodegradable and excellent in mechanical property.

In order to achieve the purpose, the invention provides the following technical scheme: a bio-based degradable environment-friendly material is characterized in that: the method specifically comprises the following steps:

s1, mixing 30-40 parts of starch, 10-20 parts of polylactic acid and 15-20 parts of thermoplastic polyurethane at high speed for 2 hours, adding 1-2 parts of auxiliary agent into the mixture, and continuously mixing for 1 hour to obtain modified starch;

s2, heating the modified starch to 110 ℃, adding 5-8 parts of coupling agent into the modified starch, stirring and mixing for 2h, drying, mixing for 1h in a double-roller open mill, and performing crosslinking plasticization between the modified starch and the coupling agent to generate a modified starch primary compound;

s3, adding 18-25 parts of glycerol into the modified starch primary compound obtained in the step S2, mixing and stirring for 2 hours, fully dispersing and lubricating the mixture, and effectively adjusting the viscosity of the mixture;

and S4, adding 50-60 parts of polyethylene and 1-2 parts of hydrolysis resisting agent into the mixture, uniformly mixing, and feeding into a double-welding-rod extruder for granulating to obtain the finished product.

In the above-mentioned bio-based degradable environment-friendly material, the coupling agent in the step S2 is an aluminate coupling agent.

In the above biodegradable environment-friendly material, the additives in the step S4 are: ethylene-vinyl acetate copolymer (EVA), Polycaprolactone (PCL) and polyhydroxyalkanoate.

In the above-mentioned bio-based degradable environment-friendly material, the assistant in the step S1 is light calcium powder or nano silica particles.

In the above-mentioned bio-based degradable environment-friendly material, the drying temperature in the step S2 is 70 to 90 ℃.

Compared with the prior art, the invention has the advantages that: the bio-based degradable environment-friendly material has the advantages that the formula science synthetic route is simple in process, reactors used in the experimental process are relatively few, and the whole experimental process is carried out under normal pressure; the preparation method takes polyethylene and starch as raw materials, and can effectively improve the flexibility and the wear resistance of the polyethylene/starch bio-based environment-friendly bag by adding thermoplastic polyurethane into a reaction system; on the other hand, the mechanical property of the polyethylene/starch bio-based environment-friendly material can be effectively improved by adding the hydrolysis-preventing agent into the reaction system, and the water resistance of the environment-friendly material is improved; in the bio-based degradable environment-friendly material, polyethylene and cheap and easily-obtained starch are mainly used as raw materials, a coupling agent, an auxiliary agent, a plasticizer and the like are added into a reaction system, so that the biochar content of the bio-based degradable environment-friendly material can be increased, the biochar content of the bio-based degradable environment-friendly material in the current market is generally below 18 percent, the biochar content of the bio-based degradable environment-friendly bag can reach above 25 percent by adopting the preparation method, and compared with the traditional bio-based degradable environment-friendly material, the biochar content in the bio-based degradable environment-friendly material is greatly increased and greatly improved.

The bio-based degradable environment-friendly material has the following advantages;

1. the paint has excellent water resistance, oil resistance and other properties;

2. has suitable shelf life and is not easy to deteriorate;

3. the waste is easy to degrade, and no harmful substances and gas are released after combustion;

4. gas and other substances are not released in the using process;

5. the content of the biochar reaches more than 25 percent.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, although the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention will be explained in more detail below with reference to specific examples: