Analysis of the performance and application advantages and disadvantages of raw materials for blister packaging

There are many types of raw materials such as plastic sheets and coils that can be used for blister packaging products, and they are widely used. Among them, the more common raw materials for blister packaging are: polyvinyl chloride (PVC), polyester (PET or PETP), polyethylene (PE), polypropylene (PP), polyvinylidene chloride (PVDC), polycarbonate (PC) and other six kinds of plastic packaging materials.

In actual application, it is necessary to select suitable raw materials according to the requirements of the packaged products for blister packaging products. For example: anti-static sheets such as PETPS for electronic product packaging; environmentally friendly and non-toxic sheets for food blister packaging products; flocking trays for cosmetic product packaging, etc. The following are the main raw materials. Performance and application advantages and disadvantages.

PVC blister packaging sheet – polyvinyl chloride (PVC sheet) PVC plastic sheets can be roughly divided into three categories: soft products, hard products and paste products.

The plasticizer in soft products is about 20%, and the plasticizer in hard products is not less than 5%. Because hard PVC contains no or very little plasticizer, its finished product has no plasticizer odor, and has excellent mechanical strength, light weight, and stable chemical properties, so the PVC blister containers made of it are widely used for beverage packaging.

The PVC resin used for beverage blister packaging is only allowed to contain 1 mg of vinyl chloride monomer. Beverages packaged with blister packaging products produced with this PVC material cannot be detected in food.

PET blister packaging sheet – polyester (PET/PETP sheet) PET/PETP sheet is a colorless, transparent, crystalline, and extremely tough plastic material. It has the appearance of glass, is odorless, tasteless, non-toxic, easy to burn, and has good air tightness.

PET plastic material has a small expansion coefficient and a low molding shrinkage rate of only 0.2%, which is one-tenth of polyolefins, and is smaller than PVC and nylon, so the product size is stable. In addition, blister packaging products produced with PET material have good mechanical strength, and their expansion degree is similar to that of aluminum. The film strength is 9 times that of polyethylene (PE), 3 times that of polycarbonate and nylon, and the impact strength is 3 to 5 times that of general films.

The film has moisture-proof and fragrance-preserving properties. Although polyester (PET/PETP sheet) has the above advantages, its film is expensive, difficult to heat-seal, and easy to carry static electricity, so it is rarely used alone. Most of them are coated with resins with good heat-sealability to make composite films. In recent years, the production of PET blister bottles has developed rapidly, and heat-resistant PET bottles are widely used in tea beverages, fruit juice beverages and other beverages that need to be hot-canned.

PE blister packaging sheet – Polyethylene (PE) Polyethylene (PE) is the world’s largest synthetic resin and the most consumed plastic packaging material, accounting for about 30% of plastic packaging materials. Its performance advantages are mainly reflected in its good transparency, softness, high elongation, better impact resistance and low temperature resistance than HDPE. It is still used in large quantities in various types of packaging, but its disadvantages are more obvious as a food packaging material.

PC blister packaging sheet – Polycarbonate (PC) PC is a colorless, transparent, smooth and beautiful plastic. Since PC is non-toxic, odorless, has good UV resistance and moisture-proof and fragrance-preserving properties, has a wide temperature range, does not crack at -180°C, and can be used for a long time at 130°C, it is an ideal food packaging material.

PC can be made into bottles, cans and containers of various shapes by taking advantage of its good impact resistance and easy molding, and is used to package beverages, alcohol, milk and other fluid substances.

The biggest disadvantage of polycarbonate (PC) is stress cracking. In production, in addition to selecting high-purity raw materials and strictly controlling various processing conditions, the use of resin modification with low internal stress, such as melt blending of a small amount of polyolefins, nylon, polyester, etc., can significantly improve stress cracking resistance and water resistance.

PVDC blister packaging sheet – polyvinylidene chloride (PVDC) PVDC is characterized by softness and extremely low air and water permeability, which can prevent odor from penetrating, good freshness and fragrance preservation, and is suitable for long-term storage of food; it has excellent acid, alkali, chemical and grease resistance, good heat shrinkage, and is suitable for sealed packaging. It is a better heat shrink packaging material.

The disadvantages of PVDC are that it is too soft and has poor handling performance; it has strong crystallinity, is easy to crack and perforate, and has poor aging resistance; its monomer is also toxic, so it is mainly used as a coating material or to make composite materials.

PP blister packaging sheet – polypropylene (PP) The raw material of polypropylene (PP) plastic is a highly crystalline structure, with a permeability of 1/4 to 1/2 of polyethylene (PE), high transparency, smooth surface, and good processing performance. It is widely used in the preparation of fibers and molded products, and is often used in plastic films.

All types of polypropylene (PP) plastic materials have a common characteristic of being statically charged. To solve this problem, antistatic agents are generally applied to PP materials. Applying polyvinylidene chloride resins with good air tightness on PP plastic materials can improve the oxidation resistance of PP.

At present, polypropylene (PP) coated films with air tightness and easy heat sealing and composite plastic materials made with other films, cellophane, paper, aluminum foil, etc. have been mass-produced. Blister packaging containers formed by blistering PP composite materials can be used for packaging of food, beverages and other products.