Application of the hottest composite packaging mat

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Application of composite packaging materials in yoghurt soft packaging

yoghurt is formed by acidification of fresh milk or its products. It is a very important product in the dairy industry at present. Yoghurt in the traditional sense refers to the milk that is redissolved from whole milk, complete or incomplete skimmed milk, concentrated milk (or milk powder), which is fermented under the action of lactic acid bacteria after homogenization (or non homogenization), sterilization. Generally, fresh milk or milk powder is formed by fermentation of lactic acid bacteria at 40 ~ 45 ℃ until the pH value of the fermented product reaches 3.5 ~ 5.0, and then refrigeration to stop fermentation. In addition to yoghurt in the traditional sense, there are many lactic acid containing drinks in the market, which are generally called blended yoghurt drinks. Because this yoghurt drink contains a variety of added ingredients, it can be reasonably nutritious, and can change various tastes according to different sales objects. It has good taste and long shelf life, so it is very popular with consumers. Yoghurt and yoghurt drinks are delicious and nutritious. Long term drinking is conducive to digestion and stomach strengthening. In recent years, it has developed rapidly in China and has become a regular consumer product in people's daily life

yogurt is traditionally packaged in glass and ceramic bottles. With the development of packaging technology, new packaging materials and the modernization of packaging equipment, plastic, composite flexible packaging materials and containers have occupied a leading position in the packaging of yogurt and other dairy products. Of course, traditional glass and ceramic containers still have a certain amount of applications, and in order to meet the demand of high-end consumption, yogurt (especially yogurt drinks) packaged in metal containers (mainly three piece cans) have also appeared in the market. This article mainly introduces the application of plastic and composite flexible packaging materials in the packaging of yogurt and yogurt drinks

characteristics of composite packaging materials

composite packaging materials refer to the combination of two or more materials with different characteristics to form a more perfect packaging material with comprehensive properties. In many cases, single packaging materials can not meet the requirements of food packaging, including yogurt. Therefore, in the process of food packaging production, two or more packaging materials are often combined together, and their comprehensive properties are used to meet the requirements of food packaging. Composite packaging materials used in food packaging are mainly various composite packaging films. The so-called composite packaging films refer to flexible composite packaging materials with comprehensive properties based on flexible packaging materials such as paper, cellophane, plastic film and metal foil, which are obtained through coating, laminating, CO extrusion and other composite processing methods

the characteristics of composite packaging materials mainly include the following points: ① good comprehensive performance. It has the properties of all single-layer materials constituting composite materials, and its comprehensive properties are better than those of any single-layer materials. It can meet the requirements of some special packaging, such as sterilization packaging under high temperature and high pressure (120 ~ 135 ℃), packaging with high barrier performance, vacuum inflatable packaging, etc. ② Good decoration and printing effect, safe and hygienic. The printing decorative layer can be placed in the middle layer (the outer layer is made of transparent material), which does not pollute the contents and plays the role of protection and beautification. ③ With good heat sealing performance and high strength, it is convenient for automatic production and high-speed packaging operation

there are two main purposes for packaging yogurt with composite packaging materials: one is to extend the shelf life of yogurt, such as extending the shelf life of yogurt from two weeks to one month to half a year, eight months, or even more than one year (of course, in combination with relevant packaging processes); Second, in order to improve the quality of yogurt products, the project will also build a new production clean room and a laboratory for polymer outsourcing research service project to facilitate consumers' access and storage. According to the nature of yogurt and the special purpose of packaging, it is required that the selected composite packaging materials should have high strength, high barrier, good high and low temperature resistance, good weather resistance, good adaptability to packaging operation, health and safety, convenient packaging waste treatment, and certain economy. The conversion of waste plastics into 3D printing materials is beneficial to reducing energy consumption. Generally speaking: ① the inner layer shall be non-toxic and tasteless, with good oil resistance and chemical resistance (especially acid), and good heat sealing performance and adhesion. Commonly used thermoplastics include PE, CPP, EVA and ionic polymers. ② The outer layer shall have good optical performance, good printability, good wear resistance and heat resistance, and high strength and rigidity. Commonly used materials mainly include PA, pet, BOPP, PC, aluminum foil, paper and paperboard. ③ The middle layer is generally made of high barrier materials, such as aluminum foil, PVDC and other high barrier and high temperature resistant materials. In the actual use process, sometimes the above layers of materials are not all used, and sometimes more than three layers are required, such as four layers, five layers, six layers or even more. For example, a certain sterile packaging carton commonly used in practice has a structure of pe/paper/pe/aluminum foil/pe/pe, a total of six layers

composite packaging materials and their applications

plastic packaging materials can be used for packaging yogurt that is circulated and consumed for a short time. Plastic materials commonly used in yogurt packaging include monomer plastic materials and multilayer plastic composites (such as multilayer composite polyethylene materials). Yogurt packed with plastic packaging materials belongs to one-time sales packaging, and generally needs to be stored and sold at low temperature. The common recommended storage temperatures are 2 ~ 4 ℃, 2 ~ 6 ℃, 2 ~ 8 ℃ and 0 ~ 4 ℃, among which the temperature range of 2 ~ 6 ℃ is the most common; The common recommended shelf life includes 14 days, 16 days, 20 days, 24 days and 30 days. The most common shelf life is 14 days (generally stored at 2 ~ 6 ℃) and the less common shelf life is 30 days (generally stored at 0 ~ 4 ℃)

compared with paper materials, glass materials and metal materials, plastic materials have many advantages and characteristics, such as good transparency, good water and moisture resistance, good resistance (such as oil resistance, drug resistance and low temperature resistance), good processability and appropriate mechanical strength. At the same time, plastic materials are cheap and have a small proportion. Of course, plastic materials are inferior to glass materials in terms of corrosion resistance, metal materials in terms of mechanical strength, and paper in terms of printability. However, as long as reasonable selection is made and advanced plastic processing and processing technologies are combined, plastic materials have broad application prospects in yogurt and other dairy products

the plastic materials or plastic composite materials commonly used for packaging yogurt mainly include: ① polyethylene + titanium dioxide. In the production of polyethylene film, the polyethylene film produced by adding white titanium dioxide has a certain light blocking performance, which can play a certain role in shading. This is because the white titanium dioxide makes the polyethylene film appear white translucent or opaque, which greatly improves the defect (transparency) of polyethylene material for yogurt packaging, so as to meet the requirements of yogurt for opaque packaging materials. ② Multilayer composite high density polyethylene material. Commonly used are three-layer high-density polyethylene (black high-density polyethylene with carbon in the middle layer, white high-density polyethylene with titanium dioxide in the inner and outer layers) with questionable profitability of new capacity and five layer high-density polyethylene (the inner and outer layers are white high-density polyethylene containing titanium dioxide, and the middle layer is black ethylene paste containing carbon). There are two kinds of commonly used materials for bag packaging: Polyethylene + titanium dioxide and multilayer composite high-density polyethylene. Bottle packaging The commonly used materials for packaging and cup-shaped packaging are polyethylene and polystyrene

when yogurt is packed in flat bags, the printed sheet-like plastic film is generally installed at the packaging material supply part of the automatic filling machine, and the bag making, filling and sealing operations are completed during the packaging process. The sealing methods of bags are mostly the middle sealing at the back and the sealing at both ends. The packaging cost of this packaging method is low, the packaging process and packaging technology are mature and easy to operate. Flat bags are generally designed and printed with simple decoration, and the patterns are continuous. Generally, it is necessary to ensure that there is a complete pattern on each bag

when yogurt is packed in flat bags, the capacity (packaging specification) of each bag is generally marked on the packaging bag by the net content of grams or milliliters, such as 125g, 227g, 250g, 125ml, 243ml, 250ml, etc. At the same time, in this form of packaging, many small bags (usually four, five, six, eight, ten) are often packed into a larger transparent plastic bag as a sales unit; Sometimes, some brands of yoghurt have a series of flavors, such as original flavor, strawberry flavor, potato flavor, pumpkin flavor, peach flavor, apple flavor, litchi flavor, etc. when carrying out collective packaging, small bags of yoghurt with different flavors are often packed into a large bag as a packaging unit or sales unit

three sided sealed cylindrical bag packaging this kind of bag packaging is commonly used in the packaging of soybean milk and has been more and more used in the packaging of yogurt in recent years. In the production process, the advanced filling process with inflation and pressure is adopted for filling, which is to align and heat seal the two printed sheet-like plastic films, first seal the two sides longitudinally, then seal one end transversely, and then seal one end of the bag mouth. The size of one end of the bag mouth is gradually reduced, and finally form a small mouth similar to the size of the straw. The bag is cylindrical in shape. A small cut is reserved at the mouth of the bag to facilitate tearing. When drinking, you can tear it gently from the cut. Generally, this kind of packaging is only printed for simple decoration, and warning signs such as "Beware of splashing" are printed at the opening (as the pressurized filling process is used for filling, the air pressure in the container is slightly higher than the atmospheric pressure, and yogurt is easy to splash when opening)

yoghurt is packed in cylindrical bags sealed on three sides, with the specification of 250g or 250ml per bag. At the same time, similar to the flat bag packaging of yogurt, this form of packaging often adopts the multi bag container of yogurt with the same taste, or the multi bag container of yogurt with different tastes to be packaged as a sales unit

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