Due to the relatively high rigidity of the molecular chain of polypropylene, the glass transition temperature is only about 0 °C, so it is usually necessary to take measures to improve low temperature toughness in winter.
An important content of material blending modification is to improve the toughness of a plastic, so that it can meet the toughness requirements of the application occasion and environment. The more mature is the rubber (elastomer) toughening plastic technology, but in recent years, non-elastomeric toughening technology has also been developed, such as inorganic rigid particle toughening plastics. So what are the specific toughening modifiers?
Generally speaking, there are rubbers, rigid particles, alloys, grafts, etc.
So how many materials can toughen plastics?
Such as: PE (especially metallocene), CPE, EVA, SBS, sebs, EPR, EPDM, POE, ABS, ACR, MBS, rubber, etc.;
Inorganic rigid particles such as ultra-fine calcium carbonate, ultra-fine talc, nano-montmorillonite, etc.;
Rigid organic particles such as PS, AS, PMMA, etc.;
Alloy toughening such as HDPE/PC, PC/ABS, PA/ABS, etc.;
Grafts such as grafted glycidyl methacrylate, grafted POE, grafted SBS
Current situation of domestic thermoforming packaging market
There are more than 3,000 domestic thermoforming packaging companies, of which there are more than 300 factories with an annual output of thousands of tons. Due to the low investment cost of small thermoforming packaging companies, there are a large number of factories in the form of small workshops in China. Thermoforming products are mainly used in food packaging, non-food packaging and cut sheets, and the requirements for raw materials in different application fields are also different.
The main raw materials used in the domestic food thermoforming packaging production market are PP, PS and PET. Most of the PP raw materials used are colored PP materials, such as lunch boxes, meat trays, tofu trays, etc. The main colors used are milky white, black, red, etc. Natural PP is mainly used in cups, lids and meat trays; transparent PP is mainly used in cups and lids.
The domestic industrial thermoforming packaging production market is relatively complex, mainly low-end products, such as tool product packaging; mid-to-high-end industrial blister packaging, such as electronics, medicine, petrochemical and other fields. In 2017, the annual use of transparent sheets in the field of industrial thermoforming packaging in China was about 578,985 t, mainly in the fields of medical capsule blister, tool packaging (stationery, hardware supplies), electronics, and cleaning supplies.
Cutting the sheet
In the domestic cutting sheet field, the folding box part consumes the largest amount of sheet material. PP sheets are used in folding boxes, window packaging and supermarket hanging strips. A small amount of transparent PP is used in high-end folding boxes.
Among them, the amount of transparent PP mainly used in the field of food thermoforming packaging is about 26900 t, mainly used in cups and lids; the rest are non-transparent packaging, mainly used in cups, lids and food trays.
Heat-resistant lunch boxes generally do not require transparency, so the natural color material accounts for the majority. In view of this situation, after a long period of research, the Tianjin Branch Research Institute has developed a high temperature resistant PP thermoforming special material PPT5030, which has high heat resistance temperature, convenient molding, and is suitable for positive and negative pressure suction molding. User’s material problem.
The food lining is mainly used for the packaging of biscuits, potato chips, peanuts, dumplings and rice balls, and there will be a layer of packaging on the outside, which is mainly used in fast food factories. At present, the lining of domestic food is mainly transparent, and there are also milky white and so on. Generally, the storage temperature of quick-frozen products such as dumplings and dumplings is about –4°C. PET and PP are suitable materials. The snack trays used at room temperature are mainly PET, PS and PP. Manufacturers choose according to their preferences and prices.
pp food tray thermoforming machine production videohttps://youtu.be/XSJ1PdPlYUw