Security
Food-grade PET is widely used in food and beverage packaging due to its recognized safety and stability. It does not release harmful substances and meets international food safety standards, which gives consumers peace of mind when using it. However, it's important to note that PET may release some harmful substances, such as DEHP, at high temperatures. Therefore, when using PET containers, it is essential to avoid high-temperature environments to prevent the release of harmful substances.
Food-grade PP is ubiquitous in daily life, such as in supermarket food storage containers and microwave-safe lunch boxes. Why is it so popular? First of all, this material is non-toxic, odorless, and tasteless, making it extremely safe to use. Furthermore, it has excellent heat resistance; it can be microwaved without any problems, unlike some plastics that deform or release harmful substances when heated. Moreover, it has excellent chemical stability and does not easily react with other substances under normal use.
More importantly, PP material does not require the addition of any random harmful substances during the manufacturing process. Under high temperature conditions, it will not decompose into bisphenol A, a chemical substance that is harmful to the human body. This means that tableware or packaging made of PP material is safer and is especially suitable for storing food.
transparency
Food-grade PET material has extremely high transparency, allowing you to see the food inside at a glance, with its appearance and quality clearly displayed. Therefore, it is particularly suitable for use in packaging that needs to display food, such as beverage bottles that we often drink, and food jars that hold biscuits and candies. Most of these packages are made of PET. Why use it? Because businesses want to showcase the best aspects of their products to consumers in order to attract them to buy. Moreover, this packaging not only looks clean and tidy, but it can also protect food to a certain extent, preventing it from getting damp or deformed, and ensuring that the food can reach consumers intact and in good condition.
Food-grade PP has lower transparency, typically being semi-transparent. Despite its lower light transmittance, its applications are wide-ranging. Take yogurt containers as an example. The semi-transparent PP material allows people to vaguely see the thick texture of the yogurt, while also keeping the product a bit mysterious. Another common supermarket item is the tray, with fresh meat trays being a prime example. Made of PP material, these trays are durable, practical, and their semi-transparent texture makes them look clean and hygienic. Using PP for food containers and trays not only meets these needs but also ensures food safety.
Heat resistance
The heat resistance of food-grade PET is a major feature. Although it is heat-resistant, it cannot withstand high temperatures. When the temperature reaches 70-80°C, the surface of PET packaging will deform and lose its original shape. Therefore, food-grade PET is not suitable for applications requiring high-temperature sterilization or heating. If hot water is placed in PET packaging, it will easily deform, leading to packaging damage or even rendering the packaging unusable. Therefore, when selecting packaging materials, the temperature requirements during food processing should be fully considered to avoid problems caused by packaging materials that are not heat-resistant.
Food-grade PP has excellent heat resistance, typically tolerating temperatures between 110-120°C. It is also the only plastic that can be directly heated in a microwave oven, making it particularly practical. If food needs to be sterilized at high temperatures or heated before packaging, PP packaging material is perfect. Many food storage containers, such as those we often use to hold meals, and the ready-to-eat lunch boxes sold in supermarkets, are made of PP material. It's convenient and safe to use it to heat food in the microwave, without worrying about it melting or releasing harmful substances. It's so convenient in daily life.
Chemical resistance
Food-grade PET has good tolerance to acids and alkalis and can cope with the acidic and alkaline environments in everyday food. However, it won't work if it encounters strong oxidizing agents or organic solvents. For example, strong oxidizing agents like bleach and disinfectants, as well as paint thinners, can corrode PET, making it brittle, deformed, or even broken. Therefore, when packaging food, it's best to avoid letting it come into contact with these things to ensure the integrity of the packaging and the safety of the food.
Food-grade PP has good chemical stability and does not react with most chemicals except for strong oxidizing agents. This material is popular in the food and industrial sectors. For food storage containers and microwave-safe lunch boxes, PP material is very suitable because it prevents food from being corroded by chemicals. For some industrial chemical packaging, if the acidity or alkalinity is not too strong, PP material can also withstand it. Even cosmetics and cleaning product packaging can benefit from PP, preventing reactions between the internal chemicals and the packaging material, ensuring product quality stability. In short, as long as it doesn't come into contact with strong oxidizing agents, PP material is a good choice for packaging that resists chemical corrosion.
Processing performance
Food-grade PET is a bit troublesome to process. It needs to be thoroughly dried before it can be molded. If it's not completely dry, defects can easily appear during processing, such as blistering or impurities on the product surface. Moreover, PET is relatively difficult to process, and the requirements for equipment and processes during production are more stringent. This directly leads to higher manufacturing costs than some other plastic materials. Therefore, PET products are usually more expensive. Nevertheless, it is still widely used in packaging such as beverage bottles and food storage containers, mainly because of its good performance, high transparency, ability to clearly display food, and ability to ensure food safety.
Food-grade PP has excellent processing performance, easily adapting to various complex processing techniques, such as injection molding, extrusion, and blow molding. In manufacturing, PP doesn't require the same level of equipment and processes as some plastics, and molding is easier. Therefore, its manufacturing cost is relatively lower. As a result, food-grade PP is particularly popular in the packaging industry; many everyday items like food storage containers and yogurt cups are made of PP. With its low cost and good quality, it can well meet market demand, so it's no wonder that it has a place in the food packaging industry.
Applicable Scenarios
Food-grade PET is actually more suitable for packaging that needs to showcase the appearance of food but doesn't require high temperatures. Its high transparency allows for a clear view of the food's appearance and quality, making it ideal for packaging like beverage bottles and transparent food jars where consumers need to see the contents directly. However, its performance at high temperatures is not ideal; the surface typically deforms at 70-80°C, making it unsuitable for hot beverages and foods. PET is not suitable if high-temperature sterilization or heating is required.
Food-grade PP is a very practical material, especially suitable for packaging that needs to resist chemical erosion and is used for frozen foods. For example, many of the food boxes, trays, and microwave-safe containers we commonly see are made of PP material. PP has excellent chemical stability; it doesn't react with most chemicals except for strong oxidizers, making it particularly safe for food storage. Furthermore, PP is resistant to low temperatures, so frozen foods can be stored without issue, unlike some other materials that can become brittle or deform. For heating, PP containers can be placed directly in the microwave, offering convenience and speed.
Environmental protection
While food-grade PET boasts excellent environmental performance, some additives, such as catalysts and antioxidants, may be added during processing. These additives may migrate and leach out during long-term use, thus affecting food safety. For example, the catalysts used in the PET polycondensation reaction (such as antimony trioxide) and the byproducts of the reaction (such as acetaldehyde) are toxic, posing a risk of toxicity transfer. Therefore, when selecting PET as a food packaging material, it is necessary to strictly control the amount of additives used and migration limits to ensure compliance with food safety standards.
Food-grade PP has excellent environmental performance and does not release harmful gases during use, so it has very little impact on human health. It is a relatively safe plastic material, and is especially suitable for food packaging. For example, many of the food storage containers and microwave-safe lunch boxes we commonly use are made of PP material. When you use it to store food, whether you are refrigerating or heating it, you don't have to worry about it releasing harmful substances. Moreover, PP material is relatively easy to dispose of after being discarded, and it does not impose a heavy burden on the environment like some other plastics. Therefore, PP is widely used in food packaging and daily necessities, and people feel very reassured about its use.
conclusion
If you want to showcase the appearance and quality of food while also withstanding high temperatures, food-grade PET might not be suitable, as PET is prone to deformation at high temperatures. It's recommended to choose other materials better suited for high-temperature environments. However, PET has high transparency, resulting in excellent display quality.
If you need to resist chemical corrosion and package frozen foods, food-grade PP is a good choice. PP has good chemical stability, low-temperature resistance, and can be used for microwave heating, making it very practical.
Food-grade PET and PP each have their own characteristics: PET has high transparency but limited heat resistance; PP has good heat resistance and chemical stability, but slightly lower transparency. Therefore, the choice must be based on the specific application scenario and requirements to select the most suitable material.
