Blistering is a plastic processing technology that involves heating flat plastic sheets to soften them, then vacuum adsorbing them onto the surface of a mold, cooling them, and forming them. It is widely used in industries such as plastic packaging, lighting, advertising, and decoration. And vacuum formed paper packaging uses paper plastic composite products instead of plastic sheets for vacuum formed packaging.
Food grade PP will not dissolve harmful substances under normal and high temperature conditions. Food grade plastics are materials that meet national food safety requirements and do not produce toxic substances during use. Food grade PP plastic can be used to make any plastic packaging for food, such as food specific plastic bags, food plastic boxes, food straws, etc. It is safe, non-toxic, and has good resistance to low and high temperatures. PP is the only plastic that can be heated in a microwave oven and has high strength and bending resistance. It will not be damaged after 50000 drops from high altitude at -20 ℃. Food grade PP sheets are commonly used in frozen dumplings and microwave heated food packaging.
The sheets used for vacuum packaging are called hard sheets or films, and commonly used ones include PET (polyethylene terephthalate) hard sheets, PVC (polyvinyl chloride) hard sheets, and PS (polystyrene) hard sheets. Plastic packaging boxes made of PS hard sheets have low density, poor toughness, and are prone to combustion. When burned, they produce styrene gas (a harmful gas), so they are generally used to produce various industrial vacuum formed trays.
PVC hard sheets have moderate toughness and are not easy to burn. When burned, chlorine gas is produced, which has a certain impact on the environment. PVC is easy to heat seal and can be sealed with sealing machines and high-frequency machines. It is the main raw material for producing transparent vacuum formed products.
The material of the blister packaging box is PET hard sheet, which has good toughness, high transparency, is easy to burn, and does not produce harmful gases when burned. It is an environmentally friendly material, but the price is high, suitable for making high-end blister products. In European and American countries, PET hard sheet is generally required for blister shells, but it is not easy to heat seal, which brings great difficulties to sealing. In order to solve this problem, people use a material called PETG ethylene glycol modified polyethylene terephthalate. This material has both the heat sealability of PVC and the high environmental friendliness and transparency of PET, but the price is higher.
