Research on the application of antibacterial fresh-keeping packaging
the preservation of food requires not only to maintain a certain shelf life, but also to ensure that the electronic universal testing machine is nutritious and fresh for different tests of different shapes of samples. For food packaged with film, if antibacterial agents are added to the film, the growth of microorganisms on the surface of food can be effectively inhibited, and low-temperature refrigeration technology is not required. This can not only save energy, but also reduce the sales cost of food. Why does metal fatigue have a destructive effect? This is because the internal structure of the metal is actually uneven. Anti bacterial packaging systems can be divided into the following categories:
outer packaging/inner packaging food system
solid or low viscosity liquid food is in direct contact with packaging materials, such as cooked meat products and vacuum packaged food. There is no top space between food and outer packaging. In this packaging system, antibacterial agents are directly added to the film, that is, antibacterial agents are added during coextrusion in the extruder. The disadvantage of this form is that the antibacterial agent is not on the surface of the film, can not fully play its role, and will reduce the transparency of the film. The improved method is to use multilayer film to make the antibacterial agent in the innermost layer (heat sealing layer), but the thermal stability of the antibacterial agent and the compatibility with packaging materials should be considered.
food system with space on the top of the outer package/food in the package
this system is suitable for food packaged in soft packages such as cups or cartons. The added highly active antibacterial agent diffuses in the top space, which not only kills the bacteria on the food surface, but also inhibits the microorganisms in the packaging space. The antibacterial agent in the system is located in the top space and is not in direct contact with food, making it difficult for the antibacterial agent to diffuse into food, so as to ensure the safety and health of food
antibacterial agents are fixed on packaging materials
antioxidants or preservatives or even functional groups (such as amino groups) are fixed on polymer materials, and then press the OK key to enter and effectively inhibit microorganisms on the food surface, which is suitable for foods with relatively easy corruption on the packaging surface. The antibacterial agent used can be non food grade, but it is not required to be volatile. In this way, the scope of selecting antibacterial agents is expanded. According to the requirements of the packaged food, appropriate antibacterial agents are selected
the application of polyolefin multilayer coextrusion film in infusion packaging
since Tianjin Otsuka company introduced the first plastic bottle production line in the 1980s, China's infusion plastic packaging began formal industrial production. Before that, some factories in China have experimented with PVC processing infusion bags, but they have neither formed a production scale nor put them on the market on a large scale. The production of infusion plastic packaging is not only a revolution of infusion packaging, but also a revolution of infusion production process and technology. Its introduction, digestion and absorption process has greatly promoted the development of infusion packaging production in China
traditional infusion containers are glass bottles. Glass infusion bottles have experienced several changes in the development process of the past century, and there are still type I, type II, type III and non type I, non type II glass bottles. No matter what kind of glass bottle, it has some disadvantages, such as poor stability, poor mouth sealing, easy to fall off, direct contact between the rubber plug and the liquid medicine, fragile and not conducive to transportation, invisible cracking caused by collision, easy to cause liquid medicine pollution, environmental pollution when firing glass bottles, and large energy consumption
in view of the defects of glass bottle infusion containers, industrial developed countries began to study the use of polymer materials to make infusion containers in the 1960s. In 1965, Japan began to develop polyethylene infusion containers. In 1972, Otsuka company began to produce polypropylene plastic infusion containers. Their performance characteristics are good stability, good mouth sealing, no falling objects, light weight, strong impact resistance, reduced probability of contamination of infusion products in the production process, energy conservation, disposable use is both sanitary and convenient, etc
there is a common weakness between glass bottle and plastic bottle infusion containers, that is, the infusion products need to form an air circuit in the use process, and the external air enters the bottle body to form an internal pressure to make the medicine drip out, which greatly increases the secondary pollution in the infusion process, especially in places with more miscellaneous bacteria and poor sanitary conditions in hospitals. In order to solve this problem, polyvinyl chloride (PVC) bag packaging infusion came into being. During the use of PVC plastic bag infusion, it can rely on its own tension to compress the dripping of the liquid medicine, without forming an air circuit, which greatly reduces the probability of secondary pollution. However, the characteristics of PVC material limit its application in infusion packaging. First of all, the PVC soft bag material contains PVC monomer, which is not conducive to human health. At the same time, the plasticizer (DEHP) is added to the PVC soft bag to change its performance in the production process, and DEHP may dissolve out in the use process. DEHP is a harmful substance, which seriously endangers human health. PVC bags are thick in texture, which is not conducive to processing, and the transmittance of oxygen and steam is high, the temperature adaptability is poor, high temperature sterilization is easy to deform, and the tensile strength is poor. These defects of PVC material limit its application in infusion packaging
following the PVC soft bag infusion container, a polyolefin multi-layer coextrusion membrane bag infusion container with stable material, no air circuit and self balancing pressure has developed rapidly in the past 20 to 30 years
the development of polyolefin multilayer coextrusion film has experienced two stages. First, polyolefin composite film from 1980s to 1990s used adhesives between each layer of film in the production process, which is not conducive to the stability of film materials, and adhesives have a potential impact on the stability of liquid medicine; Second, polyolefin multi-layer coextrusion film developed in recent four to five years does not use adhesives in the production process, and multi-layer polyolefin materials are melt cross-linked coextrusion at the same time, which not only eliminates the instability caused by adhesives, but also increases the performance of film materials, making it safer and more effective, meeting the requirements of medicine and environmental protection, and is the development direction of infusion packaging materials
polyolefin multilayer coextrusion film production materials have strict pharmaceutical quality standards. Production is carried out under 10000 level clean conditions. Adhesives and plasticizers are not used in the production process. 100 level air blowing is used. The cylindrical film is always kept closed to avoid pollution. At present, the popular polyolefin multi-layer coextrusion films are mostly of three-layer structure, including the following types: first, the inner layer and the middle layer are mixed with polypropylene and elastic materials with different proportions, so that the inner layer is non-toxic and inert, with good heat sealing performance and elasticity; the outer layer is polyester or polypropylene materials with high mechanical strength, and the text printing is clearer after surface treatment; Second, the inner layer is a mixture of polypropylene and styrene ethylene butene styrene (SEBS) copolymer. SEBS is used in the middle layer, which increases the impermeability and elasticity of the membrane material, and polypropylene is used in the outer layer
The structure and strictly controlled production process of polyolefin multilayer coextrusion film determine that it has good heat sealing performance of film materials, is suitable for a variety of filling equipment, has good elasticity, is resistant to falling, is resistant to high temperature, can be sterilized at 121 ℃, and has good light transmittance; The membrane material has the characteristics of inert biochemical performance and good barrier performance to water vapor, oxygen and nitrogen. It is suitable for filling various electrolyte infusion, nutritional infusion and therapeutic infusion. The membrane material does not contain chloride, which will not affect the environment during post-treatmentat present, China has introduced more than 20 polyolefin multi-layer coextrusion film bag infusion packaging production lines, and more than a dozen have been put into production. With the continuous progress of technology and the reduction of film material cost, polyolefin multilayer coextrusion film will play an important role in the application of infusion product packaging
source: Chinese food additives
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