How To Choose Food-grade Plastic Materials

The original use of PET material was as artificial fiber, such as film, magnetic tape, etc. It was not used in beverage bottles until 1976. PET is used as the filling container, which is commonly known as (PET bottle).

PET bottles offer excellent hardness and toughness, are lightweight (only 1/9-1/15 the weight of glass bottles), and are easy to carry and use. They consume little energy to produce, and are airtight, non-volatile, and acid- and alkali-resistant. Therefore, in recent years, it has become an important filling container for products such as carbonated beverages, tea, juice, packaged drinking water, wine and soy sauce. In addition to these uses, PET is also commonly used in bottles for detergents, shampoos, cooking oils, condiments, sweet foods, medicines, cosmetics, and alcoholic beverages.

PET material is heat-resistant up to 70°C and cold-resistant down to -20°C. Therefore, it is only suitable for warm or cold drinks. If it is filled with high-temperature liquid or heated, it will easily deform and substances harmful to the human body will dissolve. However, scientists have found that this type of plastic may release carcinogens after 10 months of use, which is toxic to the human body. Therefore, PET beverage bottles should be thrown away after use. Do not use them as water cups or storage containers for other items to avoid causing health problems that will not be worth the cost.

HDPE material has the characteristics of high temperature resistance (110℃), good hardness, high mechanical strength and chemical corrosion resistance. It is also a non-toxic and safe material.

It is commonly used in plastic food containers, such as those for cleaning supplies and bath products. Currently, most plastic bags used in supermarkets and shopping malls are made of this material. Because it feels very crisp, it is also often used to make saddle bags.

HDPE containers can be reused after careful cleaning, but these containers are usually difficult to clean and may retain traces of the original cleaning products, becoming a breeding ground for bacteria. They are not thoroughly cleaned, so recycling is not recommended. In addition, plastic bags marked for food can be used to hold food, but it is best not to heat them in a microwave.

PVC material was invented quite early and is widely used in industrial products. Since PVC has the same advantages as other plastic materials and is excellent in processing and plasticity, coupled with its low price, it is widely used, but mostly in non-food areas such as water pipes, raincoats, school bags, building materials, plastic films, plastic boxes, etc. In container applications, it is often used to fill vegetable oils, detergents, cake boxes, and package drinking water.

However, plastic products made from this material are prone to producing two types of toxic and hazardous substances, stemming from two sources:

1. Monomers of vinyl chloride that are not fully polymerized are released during the bottle making, filling, and recycling processes. Long-term inhalation of vinyl chloride can cause lung cancer;

2. Harmful substances in plasticizers. These two substances are easily precipitated when exposed to high temperature and oil. Once the toxic substances enter the human body through food, they can easily cause cancer.

In recent years, people's environmental awareness has increased, and PVC containers have rarely been used to package food. If you happen to come across this PVC container, be sure not to expose it to heat when using it!

LDPE is ubiquitous in modern life, not because of the containers it's made of, but because of the plastic bags you see everywhere. Products made from it are odorless, non-toxic, and matte. Commonly used in food plastic parts, food packaging composite films, food cling film, medicine, pharmaceutical plastic packaging, etc.

The heat resistance is not strong. Usually, qualified PE cling film will melt when the temperature exceeds 110℃, leaving some plastic preparations that cannot be decomposed by the human body. Furthermore, when food is wrapped in cling film and heated, the fats in the food can easily dissolve harmful substances from the film.

Homemade cling film should not be wrapped around food and heated to prevent the fats in the food from dissolving harmful substances in the film. Before microwave ovens, always remove the cling film from the food.

PP material is resistant to high temperatures of 130°C and has a melting point of up to 167°C. The product can be sterilized by steam and has the advantages of acid and alkali resistance, chemical resistance, and collision resistance. It's also the only plastic container that's microwave-safe and reusable after careful cleaning.

PP containers are most commonly used in soy milk and rice milk bottles, and are also used to hold 100% pure fruit juice, yogurt, juice drinks, dairy products (such as pudding), etc. Larger containers include buckets, trash cans, laundry troughs, baskets, and more.

However, it's important to note that some manufacturers, due to cost considerations, often use PP for containers, while using PE or PS for other container components, such as the bottle cap and closure. Therefore, it's recommended to remove the bottle cap when microwave-proofing.

PS has low water absorption and good dimensional stability, and can be processed by injection molding, compression molding, extrusion, and thermoforming. Generally, PS is categorized as either unfoamed or foamed, depending on whether it has been foamed.

1. Unfoamed PS is primarily used in building materials, toys, stationery, and other applications. It is also commonly made into containers for fermented dairy products (such as Yakult, Jian Jian Mei, Duo Duo, and other dairy products or lactic acid products). In recent years, it has also been widely used in disposable tableware.

2. Foamed PS (commonly known as Styrofoam) uses a foaming agent to expand 20 to 100 times during the manufacturing process. It is used as a cushioning packaging material for home appliances or information products, or as a heat-insulating material for ice cream boxes, fish boxes, etc.

PS material is often used to make bowl-shaped instant noodle boxes and foam fast food boxes. Although PS material is both heat-resistant and cold-resistant, chemicals will be released when the temperature is too high. Therefore, never add it directly in the microwave! Also, avoid using fast food containers for piping hot food. It cannot be used to hold strong acids (such as orange juice) or strong alkaline substances because it will decompose polystyrene which is harmful to the human body.

PC is a widely used material, particularly in baby bottles and space cups. It is controversial because it contains bisphenol A. The higher the temperature, the more residual bisphenol A is released and the faster it is released. Therefore, hot water should not be stored in PC containers.

Although experts point out that theoretically, as long as BPA is 100% converted into plastic structure during the PC production process, it means that the product contains no BPA at all, let alone release. However, no manufacturer can guarantee that bisphenol A has been completely converted, so you still need to be careful during use. If a small amount of bisphenol A is not converted into the PC plastic structure, it may enter food or beverages.

Therefore, be extra careful when using this plastic container. If the bottle is numbered 07, the following measures can reduce the risk:

1. Do not heat or expose to direct sunlight during use. Do not clean the kettle in a dishwasher or dish dryer.

2. Before first use, wash with baking soda and warm water and dry naturally at room temperature.

3. If the container is dropped or damaged in any way, it is recommended to stop using it, because if there are fine grooves on the surface of plastic products, it is easy for bacteria to hide.

4. Avoid repeated use of aged plastic utensils.