Problems needing attention in selecting plastic pa

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Problems needing attention in selecting plastic packaging containers

Plastic packaging containers have a wide variety and different properties. To really use plastic packaging containers well, we need to pay attention to some principled problems

to choose a good plastic packaging container, we must first have a clear understanding of the performance of the goods to be packaged and the packaging requirements of the goods, which is the basis for avoiding blindness and selecting a good plastic packaging container

plastic packaging containers are generally made by molding, and their shape mainly depends on the molding method and the mold used. Sometimes the same (or similar) form can be prepared by different methods. For example, hollow containers are generally made by blow molding, However, it is often manufactured by roll molding (especially oversized containers, small batch containers or special-shaped containers; turnover boxes are generally manufactured by injection molding, but in some special cases, in order to meet the needs of use, calcium plastic plates are made by splicing (with the advantages of light weight and low price, but the strength is slightly inferior) or molded by pre expanded polystyrene beads (it has particularly outstanding heat insulation performance and good cushioning and seismic resistance), and it is even manufactured by sheet hot forming (low cost but limited strength)

different molding methods often have a great impact on the performance and cost of products. Therefore, when choosing plastic packaging containers, it is quite beneficial to have a general understanding of various molding methods

the characteristics of various plastics commonly used in plastic packaging containers are even more important for the correct selection of plastic packaging containers, because the material of plastic packaging containers determines the basic characteristics of plastic packaging containers

plastic packaging containers with the same or similar shape may have extremely huge differences in their performance due to different materials. For example, polycarbonate blow molding bottles and ordinary polyester stretch blow molding bottles have extremely good transparency and gloss, and are very similar in appearance, but polycarbonate bottles have outstanding high-temperature resistance (can withstand high-temperature disinfection above 120 ℃), but poor barrier performance; Ordinary polyester stretch blow molding bottles have good barrier performance, but poor heat resistance (generally recommended to be used at a temperature below 60 ℃)

another example is that polyethylene containers have good acid and alkali resistance, but are not resistant to many organic solvents; Nylon containers are resistant to hydrocarbons and organic solvents, but have poor acid and alkali resistance (especially poor acid resistance). Polycarbonate bottles can be used for the packaging of goods (such as juice) filled under high temperature, but if polycarbonate bottles are used to contain carbonated beverages that need good barrier (to prevent the escape of carbon dioxide in beverages) or edible oil (to prevent oxygen from entering the bottles, so as to avoid the oxidation and rancidity of edible oil), they can not protect goods well and can not get ideal packaging effect; The use of ordinary polyester stretch bottles to package carbonated beverages can effectively prevent the escape of carbon dioxide in beverages (we will go straight ahead with excellent barrier performance of polyester stretch bottles). When it is used in the packaging of edible oil, it can delay the oxidative deterioration of edible oil and extend its shelf life (polyester stretch bottles have good barrier performance of oxygen, which can effectively prevent oxygen in the atmosphere from entering the bottle through the wall of the container), However, when it is used to pack high-temperature filled fruit juice and other goods, the polyester stretch bottle will deteriorate seriously and lose its use value

polyethylene works will produce new vitality due to continuous changes over time. Bottles can contain substances such as acid and alkali, but not organic solvents such as benzene and toluene (the swelling strength of polyethylene bottles decreases significantly or organic solvents escape through the container wall). Although nylon containers are not suitable for storing substances such as acid and alkali, they are very suitable for containing organic solvents such as benzene and xylene

multilayer composite containers pe/pa/pe and PE single-layer containers are almost the same in appearance. Even experts in the plastic products industry can hardly separate them from each other in appearance, but the performance differences between the two containers are indeed very large, especially in the barrier performance of oxygen, carbon dioxide, nitrogen and organic solvents, which can be dozens or even hundreds of times different, Therefore, we must not judge the adaptability only from the appearance of plastic containers, but also grasp the basic characteristics of plastic containers, otherwise it will often cause huge losses due to the improper selection of plastic containers

therefore, when selecting plastic containers, we must fully understand the relevant properties of plastics, and we must not act rashly. When we cannot get the exact information about the properties of plastic packaging containers, it is recommended to conduct a simulated packaging test in advance before deciding to choose plastic packaging containers

the above emphasizes the importance of selecting and using plastic packaging containers to support the utilization and development of high-yield composite production technology. At the same time, it should also be noted that in many application fields, there are many kinds of interchangeability of plastic packaging containers. In fact, a variety of plastic packaging containers coexist and compete in some applications, which is also quite common. Among them, the most common ones are plastic packaging containers such as cups and plates used in cold drink packaging and sales packaging of fruits, vegetables, aquatic products, meat and other commodities in supermarkets

the basic requirements for this kind of plastic packaging containers are reliable sanitary performance, elegant appearance and low cost, while there are generally no special requirements for mechanical strength, barrier performance and other properties. 3 Pressure transmission: pneumatic, so high impact polystyrene sheet thermoforming container, biaxial tensile polystyrene sheet thermoforming container, polypropylene styrene sheet thermoforming container, PVC sheet thermoforming container, polypropylene sheet thermoforming container and even polyester sheet (APET) thermoforming container can be used

in fact, these containers are often used at the same time. For another example, daily chemical products such as detergents and shampoos can be packaged in both polyethylene bottles and PVC bottles. Using PVC bottle packaging can improve its high transparency and gloss, and improve the attractiveness of goods to customers; The use of polyethylene bottles can win customers' favor through peculiar shape design, coloring and surface modification (printing, bronzing, etc.)

note the interchangeability of plastic packaging containers in use, which is very beneficial to commodity manufacturers. After mastering this knowledge, we can timely change the varieties of plastic packaging containers according to the changes in the prices of various plastic packaging containers in the market, reduce production costs, or find appropriate alternative plastic packaging containers in time and take the initiative in case of difficulties in supply channels

source: recycled plastics in China

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