Application of Nanotechnology in New Packaging Materials (3)

Nano-modification technology of traditional packaging materials

(I) Modification of plastic packaging materials

1. The addition of nanoparticles not only plays a reinforcing role but also has many new features. For example, a transparent plastic packaged food made by adding 0.1%-0.5% of nano titanium dioxide can not only prevent the damage of ultraviolet rays on food, but also keep the food fresh, and dope the metal nanoparticles into the chemical fiber. In products or papers, the electrostatic effect can be greatly reduced. Nanoparticles can also be used as conductive coatings, printing inks, and making solid lubricants.

2. The filling of polyethylene with new nano plastic materials has greatly improved the toughness and impact resistance of the increased products (such as plastic steel, doors and windows, packaging barrels, bags, etc.). Filling nanoplastics into nylon can increase tensile strength by 40%, tensile modulus by 68%, flexural strength by 60%, flexural modulus and impact strength by 126%, and oxygen transmission rate by 50%. Water The vapor transmission rate was reduced by 30% or less, while the product cost was reduced by 1. Adding nano-materials to enhance the modified PTFE, compared with pure tetrafluoroethylene, not only the mechanical properties have been improved, its wear resistance has been increased by more than 100 times. Some nano-plastics also have good flame-retardant and white-extinguishing properties. In addition to the above-mentioned properties, nano-plastics new materials have the characteristics of high melt strength, high crystallization speed, and low melt viscosity. Therefore, they have excellent processing properties regardless of injection molding, extrusion, and blow molding.

3. The shed film made by adding nano-plastic new material in polyvinyl fluoride can totally reflect the ultraviolet rays, avoid the degradation of the PVC film due to the absorption of ultraviolet light, and the anti-aging performance can be increased by 50%. The addition of a degrading agent to a new nanoplastics material combined with polyethylene to produce a degradable plastic film can absorb ultraviolet light in the sunlight at wavelengths between 290 and 380 nanometers, rapidly aging and disintegrating the plastic macromolecules. It turns into a powder soon after it becomes a low-molecular substance, and it eventually degrades completely, making it an environmentally friendly product that can completely eliminate “white pollution”.

4. Nanometer plastics new materials have high technological content and low cost (only 50% of ordinary plastics) and can be widely added to plastic products, industrial packaging, plastic building materials, and fast food appliances. What is even more amazing is that if a degrading agent or herbicide is added to the material, it can be used in combination with ordinary polyethylene (PE) to produce a degradable grass film with a lower cost than conventional agricultural film. This nanotechnology has passed. And officially put into production.

5. High barrier properties are an important performance indicator for food packaging materials. In order to improve the barrier property of the material, a plurality of materials are generally used for multi-layer recombination, the process is complicated, and the cost is relatively high. If nanotechnology is used, the use of nanoscale inorganic materials to modify nylon-6 PET, PP, PE, etc., will significantly improve its barrier properties, mechanical properties and transparency, and get better food packaging materials. Nano-type PA, PP, PE, PS, PET, PEN, PBT, LCP and other composite materials (add different nano materials) have been used in aseptic packaging, antibacterial packaging, deodorant packaging, high resistance packaging, and others are available In special packaging such as anti-static packaging, dangerous goods packaging and so on. The degree of application in the packaging field depends on various factors such as the production regulations of nanocomposites, material costs, packaging applications and packaging items.

(II) Nano-modification of rubber and glass

1 The traditional properties of polymer materials such as plastics, rubber, and chemical fiber are modified. After adding 4% of hollow nano-materials factory to tire rubber, the wear resistance and tear strength are improved by 3-5 times and the tire is greatly improved. The service life can also be made into various colors. Adding nanomaterials to ethylene, polyester (polyester), and propylene (propylene) can increase the strength, increase the color-enhancing properties (acid, anion, reactive dyes can be used), and can increase Conductivity, from the surface to make the product anti-static. Compared to other nanomaterials plants using hollow nano-materials plant, because solid material has a larger bonding surface, stronger polarity and non-polarity, can be in the polymer One or more of the units or units are first added to the hollow nanomaterials plant for 1-4% repolymerization, so that the open (or mesh) molecules of the polymer pass through the gaps (holes) of the nanomaterial plant, nanomaterials plant and high-polymerization Between the objects, the polar bond force is increased, and the nanomaterial configuration is the same as that of the corundum. Therefore, the polymer materials such as plastics, rubber, and chemical fiber are modified to a much higher degree than the solid nanomaterials.

2 The dispersion of nano-alumina into the transparent glass does not affect the transparency but also improves the high-temperature impact toughness. The conductor nano-particles (arsenic, antimony, silicon) prevent the trivalent nonlinear coefficient in glass or organic polymers. Nano-alumina particles are placed in organic glass (PMMA) and exhibit good broadband infrared absorption properties. In particular, nano-SiO2 has transparency and attractiveness to ultraviolet rays. In the production of organic glass, surface modified nano-SiO2 is added. Can make organic glass anti-ultraviolet radiation and achieve the purpose of anti-aging.

3. Inorganic material ceramic and glass package

Containers or ceramic packaging is a typical traditional packaging. In recent years, countries such as Western Europe, the United States, and Japan have developed nanotechnology and added nano-particles to ceramics or glass to obtain tough ceramics or glass materials, bringing new hope to the ceramic packaging and glass packaging industry.

(c) Nano-modification of wood

1. - A magic ceramic wood has been produced. It is made of high-purity lime and high-purity silicic acid plus other raw materials. With the characteristics of natural wood, its weight is almost equal to that of ordinary wood. It can be processed at will, with the characteristics of non-combustible and non-corrosive. It can be colored easily and can replace pencils and packaging products instead of wood.

2. Wood modification. Treating the surface of the wood with nano-materials can greatly improve its properties including hardness, strength, crack resistance, etc., so that the low-grade wood structure can achieve the performance of high-grade wood, and high performance can also be achieved in wood adhesives and wood coatings.

3. In the pulping and papermaking process, nanotechnology can be used to produce high-grade functional paper products called "nanopaper", nanotechnology can also be used to produce nanometer activated carbon, nano-adhesives, etc. In the forest chemical, forestry industry: (furniture, plywood) has good Application prospects.

Conclusion

Nanomaterials have distinct characteristics from traditional packaging materials and are the first breakthrough and most promising areas for early nanotechnology in the packaging industry. The two elements or compounds that are fundamentally co-dissolved in the conventional phase diagrams can form co-solubilizers in the nanostate and can be made into new materials or composites. To this end, the nano-system has greatly enriched the transformation of packaging materials and the scope of application of new packaging materials.

(Author/Chen Xirong)

China Packaging News