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Research and development technology of green packaging materials

green packaging materials are the key to the development of green packaging. Countries all over the world attach great importance to them and have made a series of important achievements. In order to make the domestic packaging industry understand the development trends of green packaging and better promote the development of green packaging in China, this paper introduces the progress of research and development of green packaging materials, including recyclable or recycled packaging materials, lightweight, thin, fluorinated free, high-performance packaging materials, degradable plastics, natural plant fiber packaging materials, edible packaging materials, agricultural and sideline products polymer packaging materials, nano packaging materials, Genetically modified packaging materials, green packaging auxiliary materials and green packaging additives

recyclable or recycled packaging materials

many countries in the world attach importance to the development of product recycling technology, and through the deposit recovery system, glass packaging bottles or polyester bottles such as beer, beverage, soy sauce, vinegar and so on are reused for many times. For example, Sweden and other countries have developed a sterilization and washing technology, so that PET beverage bottles and PE milk bottles can be reused for more than 20 times; Recycling is not only a good way to solve solid waste, but also an effective way to solve material sources and alleviate environmental pollution. The recycling technology of plastic waste includes raw material direct recycling, physical modification recycling, chemical modification recycling and other technologies. The physical method refers to the direct and thorough purification, crushing and recycling of plastic, which is then directly used in the production of packaging containers, or the polyester is crushed and washed as a sandwich material and placed in two layers of primary resin layers to make a multi-layer PET packaging container; The chemical method refers to that after crushing and washing the recovered pet, the depolymerizer methanol, water, ethylene glycol or diethylene glycol is used to depolymerize the pet completely or partially into monomers or oligomers under the action of alkaline catalyst, and then the monomers or oligomers are re polymerized into regenerated PET resin materials after purification

after the glass and metal packaging containers are discarded, they are generally recycled as raw materials by melting or remelting ingots. After the paper and paperboard are used and discarded, they can be shredded, dredged and bleached to obtain pulp and produce recycled paper

degradable plastic packaging materials

at present, the only fully biodegradable polymers that have been confirmed are biosynthetic aliphatic polyesters, such as PHB and pH - bv synthesized by fermentation, polymers containing ether bonds and polyhydroxy groups such as starch and cellulose, as well as synthetic polyamides, polyurethane, polymers containing ether bonds and PVA. Among these polymer materials, polyurethane, polyamide, polyester and PVA are all packaging materials with good performance, which are widely used as packaging films, packaging containers or binding materials. However, these completely degradable packaging materials have limited varieties, which are far from meeting the requirements of many packaging technologies and packaging protection performance. PHB, PHBV and polyether are not very useful because of their low melting point and strength

incomplete degradable plastic (starch + PE type) blended with starch, also known as bio splitting plastic, is a material with rapid research and development, many industrialization achievements and is expected to continue to reduce costs. In order to improve the blending compatibility between starch and polymers, starch must be modified. In this case, the surface of modified starch particles is covered by alkyl, which weakens the role of hydrogen bond, and thus increases the compatibility with polyethylene, polyvinyl alcohol and other polymers

photodegradable materials obtained by adding photosensitizers, such as PE, PP, etc. can be obtained by adding appropriate photosensitizers. TPR green packaging material developed by filltec company in Sweden is made of calcium carbonate compounded with polypropylene added with photolysis agent through special process. Its composition is very similar to egg shell and is almost harmless to the environment. It can be thermoformed, blow molded, injection molded and extruded. TPR is smooth and smooth. Films of different thickness degrade into powder after 4 - 18 months under light. It is now used in butter, ice cream and other packaging

at present, there are still the following problems in photodegradable packaging materials: ① the contradiction between photodegradation speed and the use performance of photodegradable polymers. If the photodegradation speed is too fast, although it is conducive to the treatment of waste plastics, beautify the environment and reduce pollution, it is obviously detrimental to the service performance and service life. ② The impact of photodegradation products on the ecological environment. If the products after photodegradation can continue to undergo biodegradation, and eventually become carbon or harmless substances absorbed by microorganisms, of course, it is the best. But in fact, the copolymers of ethylene, propylene and vinyl ketone have very little biodegradation ability in soil or underground waterways after photodegradation, and whether the photodegradation products are harmful to the ecological environment is also worth studying

at present, biodegradable and photodegradable plastics entering the market are mainly obtained by blending or grafting general-purpose polymers such as PE and PP with degradable polymers such as starch or cellulose, and adding photosensitizers that can induce photodegradation. Research and application in this field are very active. Polyketones can be chemically modified with oxidants such as hydrogen peroxide and peroxy acid, and oxidized into polymers containing polyester and polyketone structures at the same time, becoming packaging materials with both biodegradability and photodegradation

edible packaging materials

edible packaging materials have been widely used in food and drug packaging. The raw materials of edible packaging materials mainly include starch, protein, plant fiber and other natural substances. Among the edible packaging materials based on corn, wheat, potatoes, beans, potatoes and other crops, the modification of corn starch into edible packaging materials is the most typical, and the processing technology and practical application are relatively mature. According to the additives, acid-base treatment, enzyme treatment or oxidation treatment, it can be made into film, extruded into shape, used as film coating for small food, and can also be made into water-proof and oil-proof beverage cups and fast food boxes. Edible packaging materials made of protein can be divided into animal protein and plant protein. Animal protein is derived from animal skin, bone, cartilage tissue, etc. this kind of edible material has very good strength, water resistance and oxygen permeability, especially suitable for the packaging of meat food. The plant protein extracted from soybeans can be processed into film for packaging, which has good moisture and oxygen resistance, and has certain antibacterial properties. It is suitable for the packaging of fatty food, which not only improves the shelf life, but also maintains the original flavor of oily food

edible packaging materials of plant fibers take agricultural and sideline products such as wheat bran, soybean dregs, and marine plants such as seaweed and seaweed as the main raw materials. Although the nutritional value of this kind of materials is not high, most of them have the effects of weight loss and health care, such as sodium alginate, which is not absorbed by the human body, but has the effects of reducing blood sugar, regulating the intestines and stomach, expelling cholesterol out of the body and slowing down poisoning. Plant fibers can be made into various containers and eaten together with food after hot cooking, or when used to package instant noodles seasoning, it melts when it meets heat and dissolves when it meets water, so there is no need to unpack. It can also be made into fresh-keeping packaging paper for fruits and vegetables. The edible material with sodium alginate as the main component has impermeability to fat and vegetable oil, and is an excellent oil resistant packaging material

edible packaging materials can also be made from the shells of edible shellfish such as shrimp, crab, clam and oyster. Chitosan can be extracted from chitin under alkaline conditions. After modification, chitosan has excellent film-forming property, good oil resistance, water and moisture resistance and transparency. This kind of edible packaging materials has been widely used in the packaging of fruits, bread, ice cream and other foods

natural plant fiber packaging materials

paper made of wood pulp and straw pulp is the most widely used fiber packaging materials. In recent years, some new green paper packaging products have been developed, the typical varieties are pulp molding and honeycomb paperboard products. Pulp molded products use waste paper and plant fibers as raw materials, and different molds shape products on the molding machine. It is a three-dimensional papermaking technology. Its products are used as products to replace foamed plastic EPS, and are widely used in tableware, egg trays, fresh fruit trays, industrial trays, food and medical equipment packaging. Honeycomb paperboard is composed of two upper and lower sheets of face paper and hexagonal honeycomb core paper. It has the advantages of light weight, high strength, large stiffness, good cushioning, heat insulation and sound insulation performance. It is an ideal environmental protection material to replace wood and replace EPS as buffer liner

natural plant fibers in particular generally refer to the fibers of natural plants other than trees, such as bagasse, cotton straw, chaff, corn straw, straw, straw and waste paper. Natural plants are a renewable natural resource with rich sources. In recent years, a series of green packaging products have been developed by using natural plant fibers such as reed, straw, wheat straw, bagasse and bamboo. With bamboo as raw material, bamboo plywood packaging boxes and silk bound bamboo crates are produced for the packaging of mechanical and electrical products and heavy machinery; Bamboo, straw and other plant fibers are pressed into fiberboard after high-temperature sterilization, then crushed, added with fillers, adhesives and other mixing, and extruded to form, which can be used to make disposable tableware. If foamed and expanded, it can also be used to make buffer liners

transgenic plant packaging materials

although the research and development of biodegradable packaging materials synthesized by microbial fermentation have made breakthrough progress, there are still problems such as low production efficiency, small melting point and initial temperature difference of degradation, slow crystallization speed, difficult processing, expensive price, and limited practical application. Therefore, cultivating transgenic plants to produce fatty polyester PHB and PHAs has become a hot spot in the research and development of biodegradable plastics

with the rapid development of plant genetic engineering, in view of the high price of PHB produced by microbial fermentation, some large companies have carried out the research and development of PHB and other packaging materials produced by using transgenic plants as reactors. The long-term goal established by ici/Zeneca seed company in the UK is to introduce the pathway of bacterial biosynthesis of PHB into suitable crops, so as to use transgenic plants to produce phb/V packaging materials on a large scale; Monsanto Company of the United States launched a major project in 1996 to establish a technical system for producing packaging materials with genetically modified rape

it is reported that China has also cloned two key enzyme genes for PHB synthesis (phbB and ph2bc) from eutrophic Alcaligenes, and successfully constructed a prokaryotic vector to be introduced into E. coli, and successfully introduced this gene into potatoes. In order to increase PHB production, they completed the cloning of PHBA gene and constructed a seed specific expression vector to transform rape. The gene product will be located in the on-demand plastid of rapeseed

lightweight, thin, fluorinated and high-performance packaging materials

this is an important direction for the development of green packaging materials, which mainly focuses on the development and deep processing of existing packaging materials. On the basis of ensuring the realization of the three major functions of packaging, we should reform excessive packaging, develop appropriate packaging, minimize the use of packaging materials, reduce packaging costs, save packaging material resources, and reduce the amount of packaging material waste, Efforts have been made to develop lightweight, thin, fluorinated free and high-performance new packaging materials

for cushioning packaging materials with huge consumption, people are actively looking for fluorine-free lightweight packaging materials to replace expanded polystyrene (EPS) as shown by the latest data of China Electronic Information Industry Development Institute (CCID), such as using new lightweight foamed polyester or foamed PP as packaging containers for food, cosmetics and electronic products, This experiment shows that the animal body has good biocompatibility with the stent made of stainless steel wire. After the stent is placed, the blood vessel wall is not

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