Application of Packaging Functional Materials

[ABSTRACT] Packaging materials science is a cross subject between material science and packaging industry, and it is also a new industry. According to the characteristics of its industry, the author elaborates on the packaging functional materials, from the classification and performance of various functional materials today. In terms of functional division and other aspects, the overall introduction to the characteristics, prospects and related industrial background of packaging functional materials, and actively explore the direction of its development, to discuss certain issues encountered in China's packaging materials industry such as: environmental protection, efficiency, industry level, etc. .

Keywords: packaging functional materials

Functional materials are a branch of material that accompanies the industrial revolution. They can also describe the classification of pairs of materials. Functional materials are defined as materials that have special properties. They can be defined according to the type of material they belong to, or they can be Divided by the field of material application; that is, functional materials are specifically defined by their subjective and objective attributes. For example: ceramic was used as a container material at the beginning of its invention, its functional characteristics are limited to good barrier properties, good stiffness, and good stability. But nowadays, ceramics is used in mechanical manufacturing, and it uses its high hardness, high temperature resistance, and wear resistance features. In the engine manufacturing technology that has been put into production, ceramics are used in cylinders, pistons, and bearings. , Highly abrasive environment, and more and more used for the manufacture of other parts.

In fact, the definition of functional materials originated from Bell Laboratories. In 1965, Dr. JA Morton proposed the definition of functional materials: "With excellent electrical, magnetic, optical, thermal, acoustic, mechanical, chemical and biological functions and their mutual The transformed function is used for high-tech materials that are not structural."

Going back to our theme, packaging functional materials is the use of materials with special functions in the product packaging process. Specific to the actual production process of the packaging, various functional materials are used in different categories, for example, food packaging is widely used non-toxic, shading , Easily degradable materials; while in the shipping industry are widely used corrosion-resistant, high strength, high rigidity engineering plastics as the preferred material.

Today, with the rapid development of the material industry, more and more new materials are being manufactured and have excellent performance that cannot be achieved with previous materials. For packaging materials, there are composite flexible packaging materials and fresh packaging materials. , barrier packaging materials, decomposable packaging materials and so on. In recent years, the development of nanotechnology has also caused tremendous innovation in the packaging materials industry. We know that nanomaterials generally refer to particles in the size range of 1-100 nm, which is the transitional zone between the atomic clusters and macroscopic objects. A typical mesoscopic system. After the ordinary materials are made into the order of nano materials, the nano materials have excellent special functions such as light, force, sound, electricity, heat, magnetism, projection, and absorption, and it will have extremely unique four major effects: 1 small Size effect or volume effect; 2 surface effect and interface effect; 3 quantum size effect; 4 macro quantum tunnel effect. Due to the above four effects, nanomaterials exhibit the following properties: 1 high strength and high toughness; 2 high thermal expansion coefficient, high specific heat and low melting point; 3 abnormal electrical conductivity and magnetic susceptibility; 4 extremely strong wave absorbing property; Diffusion. It is for these reasons that nanomaterials have been rapidly developed in the packaging industry.

First of all, let's look at the preparation of nanomaterials. The preparation methods of nanomaterials include: physical and chemical methods. The physical preparation methods mainly involve physical changes such as evaporation, melting, solidification, deformation and particle size reduction, and specifically include a pulverization method, an evaporation condensation method, an ion sputtering method, a freeze-drying method, an electric spark discharge method, and an explosion sintering method. . The process of chemically preparing nanoparticles usually involves a basic chemical reaction. During the reaction, the atoms in the material are organized and arranged, which determines the existence of the substance. The chemical methods mainly include gas-phase chemical reaction method, precipitation method, hydrothermal synthesis method, spray thermal conductivity method, sol-gel method, r-ray irradiation method, and phase transfer method. On this basis, there are five types of nanocomposite materials that we can use: nanocomposite preparation methods: (1) high-energy ball milling; (2) combustion synthesis; (3) chemical vapor deposition (CVD) ); (4) Melt blending method; (5) Intrusion method (Silicon layer composite technology). In this way, we can get nanocomposites. What kind of applications does nanocomposite have?

Let's first look at the definition of nanopacks. The definition of nano packaging: Although there is no accurate definition of nano packaging, but from the perspective of nano science, nano packaging reflects the use of nano materials, nanotechnology for packaging products nano synthesis, nano addition, nano modification, make It is a general name for new physical properties of packaging that have nanostructures, dimensions, and specific functions. Nano packaging has four elements, nano packaging material elements, nano packaging container elements, nano packaging technology elements, and nano packaging information elements. Nano-packaging material: It refers to the system of nano-composite packaging materials made of nano-particles or nano-composite materials with a dispersed phase size of 1-100 nm nano-particles or crystals and other packaging materials. The object and task of nano packaging research are: to study the movement state and law of nano-packaging materials in the process of logistics, the law of the physical properties of nano-packages and the preparation technology; to study the relationship between nano-packaging and multi-disciplinary, and to propose a new packaging Concept, improve and create new packaging technology and decoration technology, shorten the process of engineering, industrialization and commercialization of existing packaging companies and nano-packaging.
From this point of view, the prospects for nano packaging will be boundless. Looking at nano-packaging applications today is nothing more than the following categories.

1. Nano-composite packaging materials With the increasing demand for special functions of packaging in the 21st century, such as anti-explosion packaging, anti-electromagnetic packaging, camouflage packaging, high-resistance packaging, stealthy packaging, anti-radar packaging, and other requirements, promote nano-packaging technology. development of. Nano packaging materials made of nano-materials have become a kind of high-tech materials we need. As far as the packaging field is concerned, in recent years, the most widely studied nanocomposites abroad are polymer-based nanocomposites (PNMC). For example, adding 10% nano TLCP (thermotropic liquid crystal polymer) to a high molecular polymer will increase the tensile strength of the material to 470 MPa, thereby greatly expanding its use and saving scarce resources.

2. Nano-antibacterial packaging materials Nano-antibacterial packaging materials have become a hot topic. Japan added a new type of inorganic antibacterial agent to packaging materials and added antibacterial agents and synergists to polyolefin films. At present, the antibacterial film is widely used. Pure natural base materials can play an amazing bactericidal effect in the transformation of nanotechnology. Antibacterial and aseptic packaging can make bacteria cells degenerate or precipitate. Once they encounter water, they will exert greater damage to bacteria. It also has strong adsorption capacity and strong penetration, and it also has strong antibacterial effect after multiple washings.

3. Nano-functional (smart) packaging materials currently developed nano-functional, intelligent packaging materials, usually made of functional materials such as photovoltaic, temperature sensitive, moisture sensitive, and packaging materials, which can identify and indicate the temperature of packaging space, Humidity, pressure, and the degree of sealing, time and other important parameters. This is a kind of functional packaging material with promising development. It can be used to prevent discoloration, rust prevention, mildew proofing, and preservation. It is usually made into functional bags or sheets. Suitable for high-end packaging and military packaging.

4. Nano-coating materials (1) Binary synergistic nano-interface materials seek to promote the synergistic dualism to the nano-interfaces, discuss new interface properties, and super-dual interface physical properties (or super-parent nano-materials), the basic principle of which is specific On the surface of the surface, a complementary nanostructure (such as a convex and a concave phase) interface structure is constructed. The concave surface of the nanostructure has stable adsorption of gas atoms and molecules, and has a stable gas film on the macroscopic surface, making the oil Or water can not be in direct contact with the surface of the material, so that the surface of the material exhibits extraordinary double sparse. At this time, the contact angle between the droplet or oil droplet and the interface tends to be maximum. In the field of packaging materials, paper products, cartons, films, etc. have also been given extraordinary super-hydrophobic, ultra-clear effect.
(2) The complete nano-coating material has been applied in the military now, and a new coating is formed by adding a small amount of nano-titanium together with the resin by means of a conventional coating technique, so that its function is upgraded, and corrosion resistance and seawater resistance are achieved. , high temperature, oxidation and aging resistance. Increase the hardness, reduce the friction formed by the self-lubrication, can also produce antibacterial, cleaning effect.

5. Nano-Adhesives and Sealants Adhesives and sealants are important products in the packaging industry and are used in a wide range of applications. Foreign countries have added nano-SiO2 as an additive to adhesives and sealants, which greatly increase the bonding effect of adhesives and the sealability of sealants. The mechanism of action is to coat a layer of organic material on the surface of nano-SiO2. To make it hydrophilic.

6. Nanoplate packaging materials The iron plates used in beverage cans have undergone the development of tinplate and tinplate (TFS). At present, the so-called third-generation nanoscale materials have been developed. In order to improve the welding sealing performance of TES, they have been successfully developed. The third-generation submicron tin TES plate has a nano-tin particle diameter of 100 nm, a tin plating amount of 100 mg/m2, a volume rate of less than 12%, and a large reduction in the volume and amount of tin plating. The new plate is safe and has good performance and is easy to be shaped. The widening of the operating parameters range, especially the improvement of the welding sealability, makes it a high-grade metal can plate. For example, the welding current range is as wide as 300-600A, making it more suitable for making beverage packaging containers.

7. Nano-luminescent materials and anti-counterfeit printing (1) Novel nano-luminescent materials can emit light in the dark for more than 12-24 hours after a few minutes of illumination, and their luminous intensity and maintaining time are more than 30 times that of traditional fluorescent materials, and the materials themselves Non-toxic, harmless, free of any radioactive elements, its stability and weather resistance are excellent. Can be used endlessly.
(2) Utilizing new wide-format laser holographic anti-counterfeiting and packaging film materials and manufacturing technology, R&D and industrial production of high-performance anti-counterfeiting and packaging film products suitable for the Chinese market, with great market potential, and moderate equipment costs and investments.

8. Nano-packaging machine parts and devices Carbon nanotubes also have high mechanical strength and high thermal conductivity. Due to their very large length-to-diameter ratio, they can produce any part with a complex shape or are a reinforcing fiber for composite packaging materials.