Wang Zhenhua, technical director and senior engineer of material performance test room of equipment research and test center, would like him to introduce relevant knowledge.

Disposable paper cup

Wang Zhenhua, a senior engineer, told reporters that disposable paper cups can be divided into cold drink cups, hot cups and ice cream cups according to their uses. According to the composition, it can be divided into wax coated cup and coating Cup. The base paper of the paper cup is the base paper for food packaging, that is, it is made of pure wood pulp, not recycled paper. In order to prevent leakage, coating or coating can be used. Generally, food grade paraffin can be used to coat the inner layer of cold drink cup, which has low heat resistance and can not exceed 40 ℃; at present, wax coated cup is less and less, and is gradually replaced by double coating Cup. The paper cup containing hot water or oil-bearing ice cream is coated with a layer of plastic film, generally polyethylene (PE) film, with high heat resistance and heat resistance temperature of 80 ℃. Using double-layer membrane, that is, attaching a layer of PE film on the inside and outside of the paper cup, has better compactness and impermeability. PE coated paper cups are more common in China, while PLA coated cups are more developed abroad, with good safety and degradation. Consumers should pay attention to the fact that the temperature of PE coating is 80 ℃, so it is not necessary to use paper cup to directly open water for tea brewing. After making tea in other high temperature resistant containers, paper cups can be used to hold warm tea.

When consumers choose disposable paper cups, there are no microbiological, physical and chemical testing equipment, but they can use the steps of seeing, smelling, photographing and kneading to judge whether the quality and safety of paper cups are qualified.

To select a qualified paper cup, the first thing is to see whether there is QS production license mark, manufacturer information and production date on the outer package of the paper cup. In addition, the scope of application indicated on the package should be checked. Regular disposable paper cups are marked with the applicable temperature of paper cups.

Then check the appearance of the paper cup. The mouth of the paper cup should not be sunken or wrinkled; the coating layer and waxing layer should be uniform, and the cup body should be clean and free of foreign matters. The more simple the printing appearance pattern and color of paper cup, the better. The printing pattern shall be clear in outline, uniform in color and free from obvious color spots. According to the provisions of the recommended national standard "paper cup" (GBT 27590-2011) which was implemented on June 1, this year, the paper cup should not be printed within 15mm from the cup mouth to the cup body and within 10mm from the cup bottom to the cup body. Although because of the protection of the film, ink components will not necessarily be brought into the food, but choose the cup with no printing at the bottom of the cup will be safer.

smell

The paper cup should be open without smell. Unqualified paper cups, such as the use of industrial paraffin wax, the use of non food grade recycled PE instead of food grade, may have some unstable low molecular components free, releasing odor, if filled with hot water, the odor may be more obvious, such situation should be treated with caution.

Knead

The national standard has the requirements of cup body stiffness and cup bottom strength. The paper cup, which is soft and flattened at a pinch, may be a shoddy product, which is not easy to use. It is easy to cause scald and other accidental injuries when using this paper cup with hot water.

mirror

Fluorescent brighteners are not allowed in paper cups. Some illegal products because of the use of recycled paper manufacturing, whiteness is not enough, add fluorescent whitening agent as the original pulp paper. Although there is no evidence that the absorption of fluorescent agents will cause harm to human body, fluorescent agents have been listed as one of the potential carcinogenic factors. If it contains fluorescent substances, it will emit blue fluorescence when irradiated by ultraviolet light. Consumers can use this principle to conduct preliminary verification with a banknote detector that can emit ultraviolet light. Although in the case of gonorrhea, fluorescent agents often do not penetrate and migrate into food quickly, but there are still potential hazards. According to the standard, if the area of fluorescence emitted by the cup body is more than 5%, the product is unqualified.

Plastic appliances

Plastic containers, water cups and other plastic utensils are used more and more widely in the family, especially in summer. How to choose the right material to ensure safety? Wang Zhenhua, a senior engineer, said that at the bottom of the plastic products, there is a triangle recycling mark with an arrow, and there is a number in the middle of the triangle. This is the code of plastic material. You can choose no according to this number Plastic utensils of the same material are used for different purposes.

"1" stands for pet (polyester): common in mineral water bottles and carbonated beverage bottles

This kind of beverage bottle can be heat-resistant to 70 ℃, and is suitable for holding warm or frozen food. When it is filled with high-temperature liquid or heated, it is easy to deform and the harmful substances will melt out. Pet may age and release harmful substances after 10 months of use. Therefore, the beverage bottles should be discarded in time when they are used up. They should not be used as water cups or recycled for a long time.

"2" stands for HDPE (high density polyethylene): soy sauce bottle, oil bottle, cleaning and bathing product bottle

HDPE can be heat-resistant from 100 ℃ to 120 ℃ and can be used for food packaging. It is generally used to make large capacity containers, turnover boxes, turnover barrels and so on.

"3" stands for PVC (polyvinyl chloride): medicine bottle and storage bottle

PVC without plasticizer is hard, used to make pipes, doors and windows, and a small amount is used for food and medicine packaging.

"4" stands for LDPE (low density polyethylene): yogurt bottle, chewing gum bottle and beverage bottle

LDPE is a general-purpose plastic with low processing temperature and no additives. It can be used to make many kinds of containers, but the service temperature can not exceed 80 ℃.

"5" stands for PP (polypropylene): fresh keeping box, microwave oven lunch box

****The plastic box that can be put into the microwave oven can be reused after careful cleaning. need