Plastic packaging film is one of the main flexible packaging materials. There are many types of plastic packaging film with different characteristics, and their uses vary according to the different properties of the packaging film.
Packaging film has good toughness, moisture resistance, and heat sealing performance, and is widely used: PVDC packaging film is suitable for packaging food and can maintain freshness for a long time; And water-soluble PVA packaging film can be used without opening and directly put into water; PC packaging film is odorless, non-toxic, with transparency and luster similar to glass paper, and can be steamed and sterilized under high temperature and pressure.
In recent years, the global demand for plastic packaging film has shown a continuous upward trend, especially as packaging forms continue to shift from hard packaging to soft packaging. This is also the main factor driving the growth in demand for packaging film materials. So, do you know the types and uses of plastic packaging film? This article will mainly introduce the properties and uses of several plastic packaging films
1. Polyethylene packaging film
PE packaging film is a widely used plastic packaging film, accounting for over 40% of the total consumption of plastic packaging film. Although PE packaging film is not ideal in terms of appearance, strength, etc., it has good toughness, moisture resistance, and heat sealing performance, and is easy to process and form at a low price, so it is widely used.
a. Low density polyethylene packaging film.
LDPE packaging film is mainly produced by extrusion blow molding and T-mold methods. It is a flexible and transparent packaging film that is non-toxic and odorless, with a thickness generally between 0.02-0.1mm. Has good water resistance, moisture resistance, drought resistance, and chemical stability. A large amount of general moisture-proof packaging and frozen food packaging used for food, medicine, daily necessities, and metal products. But for items with high moisture absorption and high moisture resistance requirements, better moisture resistant packaging films and composite packaging films need to be used for packaging. LDPE packaging film has high air permeability, no fragrance retention, and poor oil resistance, making it unsuitable for packaging easily oxidized, flavored, and oily foods. But its breathability makes it suitable for fresh-keeping packaging of fresh items such as fruits and vegetables. LDPE packaging film has good thermal adhesion and low-temperature heat sealing properties, so it is commonly used as an adhesive layer and heat sealing layer for composite packaging films. However, due to its poor heat resistance, it cannot be used as a heat sealing layer for cooking bags.
b. High density polyethylene packaging film. HDPE packaging film is a tough semi transparent packaging film with a milky white appearance and poor surface glossiness. HDPE packaging film has better tensile strength, moisture resistance, heat resistance, oil resistance, and chemical stability than LDPE packaging film. It can also be heat sealed, but its transparency is not as good as LDPE. HDPE can be made into thin packaging film with a thickness of 0.01mm. Its appearance is very similar to thin silk paper, and it feels comfortable to the touch, also known as paper like film. It has good strength, toughness, and openness. To enhance the paper like feel and reduce costs, a small amount of lightweight calcium carbonate can be added. HDPE paper film is mainly used to make various shopping bags, garbage bags, fruit packaging bags, and various food packaging bags. Due to its poor airtightness and lack of fragrance retention, the storage period of packaged food is not long. In addition, HDPE packaging film can be used as a heat sealing layer for cooking bags due to its good heat resistance.
c. Linear low-density polyethylene packaging film.
LLDPE packaging film is a newly developed variety of polyethylene packaging film. Compared with LDPE packaging film, LLDPE packaging film has higher tensile and impact strength, tear strength, and puncture resistance. With the same strength and performance as LDPE packaging film, the thickness of LLDPE packaging film can be reduced to 20-25% of LDPE packaging film, thereby significantly reducing costs. Even when used as a heavy packaging bag, its thickness only needs to be 0.1mm to meet the requirements, which can replace the expensive polymer high-density polyethylene. Therefore, LLDPE is very suitable for daily necessities packaging, frozen food packaging, and is also widely used as heavy packaging bags and garbage bags.
2. Polypropylene packaging film
PP packaging film is divided into unstretched packaging film and biaxially stretched packaging film. The two types of packaging film have significant differences in performance, so they should be considered as two different types of packaging film.
1) Unstretched polypropylene packaging film.
Untretched polypropylene packaging film includes blown polypropylene packaging film (IPP) produced by extrusion blow molding method and extruded cast polypropylene packaging film (CPP) produced by T-mold method. The transparency and toughness of PP packaging film are poor; And it has high transparency and good toughness. CPP packaging film has better transparency and glossiness, and its appearance is similar to that of glass paper. Compared with PE packaging film, unstretched polypropylene packaging film has better transparency, glossiness, moisture resistance, heat resistance, and oil resistance; High mechanical strength, good tear resistance, puncture resistance, and wear resistance; And it is non-toxic and odorless. Therefore, it is widely used for packaging food, pharmaceuticals, textiles and other items. But it has poor drought resistance and becomes brittle at 0-10 ℃, so it cannot be used for packaging frozen foods. Untretched polypropylene packaging film has high heat resistance and good heat sealing performance, so it is commonly used as a heat sealing layer for cooking bags.
2) Biaxially oriented polypropylene packaging film (BOPP).
Compared with unstretched polypropylene packaging film, BOPP packaging film mainly has the following characteristics: ① Improved transparency and glossiness, comparable to glass paper; ② Mechanical strength increases, but elongation decreases; ③ Improved cold resistance and no brittleness even when used at -30~-50 ℃; ④ The moisture permeability and air permeability are reduced by about half, and the organic vapor permeability is also reduced to varying degrees; ⑤ Single film cannot be directly heat sealed, but its heat sealing performance can be improved by coating adhesive with other plastic packaging films.
BOPP packaging film is a new type of packaging film developed to replace glass paper. It has the characteristics of high mechanical strength, good toughness, good transparency and glossiness. Its price is about 20% lower than that of glass paper. So it has replaced or partially replaced glass paper in packaging for food, medicine, cigarettes, textiles, and other products. But its elasticity is high and cannot be used for candy twisting packaging. BOPP packaging film is widely used as a base material for composite packaging films. Composite packaging films made from aluminum foil and other plastic packaging films can meet the packaging requirements of various items and have been widely applied.
3. Polyvinyl chloride packaging film
PVC packaging film is divided into soft packaging film and hard packaging film. The elongation, tear resistance, and cold resistance of soft PVC packaging film are good; Easy to print and heat seal; Can be made into transparent packaging film. Due to the odor of plasticizers and the migration of plasticizers, soft PVC packaging film is generally not suitable for food packaging. But the soft PVC packaging film produced by internal plasticization method can be used for packaging food. Generally speaking, PVC flexible packaging film is mainly used for industrial products and non food packaging.
Hard PVC packaging film, commonly known as PVC glass paper. High transparency, stiffness, good toughness, and stable twisting; Has good air tightness, fragrance retention, and good moisture resistance; Excellent printing performance, can produce non-toxic packaging film. It is mainly used for twisted packaging of candies, packaging of textiles and clothing, as well as outer packaging film for cigarette and food packaging boxes. However, hard PVC has poor cold resistance and becomes brittle at low temperatures, making it unsuitable as a packaging material for frozen food.
4. Polystyrene packaging film
PS packaging film has high transparency and glossiness, beautiful appearance, and good printing performance; Low water absorption and high permeability to gases and water vapor. Untretched polystyrene packaging film is hard and brittle, with low extensibility, tensile strength, and impact resistance, so it is rarely used as a flexible packaging material. The main packaging materials used are biaxially oriented polystyrene (BOPS) packaging film and heat absorbing packaging film.
The BOPS packaging film produced by biaxial stretching has significantly improved its physical and mechanical properties, especially elongation, impact strength, and toughness, while still maintaining its original transparency and glossiness. The good breathability of BOPS packaging film makes it very suitable for packaging fresh foods such as fruits, vegetables, meat and fish, as well as flowers.
5. Polyvinylidene chloride packaging film
PVDC packaging film is a flexible, transparent, and high barrier packaging film. It has moisture resistance, air tightness, and fragrance retention properties; And it has excellent resistance to strong acids, strong alkalis, chemicals, and oils; Untretched PVDC packaging film can be heat sealed, which is very suitable for packaging food and can maintain the flavor of food unchanged for a long time.
Although PVDC packaging film has good mechanical strength, its stiffness is poor, it is too soft and prone to adhesion, and its operability is poor. In addition, PVDC has strong crystallinity, and its packaging film is prone to perforation or microcracks, coupled with its high price. So currently, PVDC packaging film is less commonly used in single film form and mainly used for making composite packaging film.
6. Ethylene vinyl acetate copolymer packaging film
The performance of EVA packaging film is related to the content of vinyl acetate (VA). The higher the VA content, the better the elasticity, stress cracking resistance, low temperature resistance, and heat sealing performance of the packaging film. When the VA content reaches 15%~20%, the performance of the packaging film is close to that of soft PVC packaging film. The lower the VA content, the less elastic the packaging film is, and its performance is closer to LDPE packaging film. The content of VA in general EVA packaging film is 10%~20%.
EVA packaging film has good low-temperature heat sealing and inclusion sealing properties, making it an excellent sealing film and commonly used as a heat sealing layer for composite packaging films. The heat resistance of EVA packaging film is poor, with a usage temperature of 60 ℃. Its airtightness is poor, and it is prone to adhesion and odor. So single-layer EVA packaging film is generally not directly used for packaging food.
7. Polyvinyl alcohol packaging film
PVA packaging film is divided into water-resistant packaging film and water-soluble packaging film. A water-resistant packaging film is made from PVA with a polymerization degree of over 1000 and complete saponification. The water-soluble packaging film is made from PVA partially saponified with low polymerization degree. The main packaging film used is water-resistant PVA packaging film.
PVA packaging film has good transparency and glossiness, is not easy to accumulate static electricity, is not easy to adsorb dust, and has good printing performance. Has air tightness and fragrance retention in a dry state, and good oil resistance; Has good mechanical strength, toughness, and stress cracking resistance; Can be heat sealed; PVA packaging film has high moisture permeability, strong absorption, and unstable size. So, polyvinylidene chloride coating, also known as K coating, is usually used. This coated PVA packaging film can maintain excellent airtightness, fragrance retention, and moisture resistance even under high humidity, making it very suitable for packaging food. PVA packaging film is commonly used as a barrier layer for composite packaging film, which is mainly used for packaging fast food, meat products, cream products and other foods. PVA single film is also widely used for packaging textiles and clothing.
Water soluble PVA packaging film can be used for measuring packaging of chemical products such as disinfectants, detergents, bleaching agents, dyes, pesticides, and patient clothing washing bags. It can be directly put into water without opening.
8. Nylon packaging film
Nylon packaging film mainly includes two types: biaxially stretched packaging film and unstretched packaging film, among which biaxially stretched nylon packaging film (BOPA) is more commonly used. Untretched nylon packaging film has outstanding elongation and is mainly used for deep stretch vacuum packaging.
Nylon packaging film is a very tough packaging film that is non-toxic, odorless, transparent, glossy, not prone to static electricity accumulation, and has good printing performance. It has high mechanical strength, three times the tensile strength of PE packaging film, and excellent wear resistance and puncture resistance. Nylon packaging film has good heat resistance, sweat resistance, and oil resistance, but it is difficult to heat seal. Nylon packaging film has good air tightness in a dry state, but it has high moisture permeability and strong water absorption. In high humidity environments, dimensional stability is poor and airtightness sharply decreases. Therefore, polyvinylidene chloride coating (KNY) or composite with PE packaging film is often used to improve its water resistance, moisture resistance, and heat sealing performance. This NY/PE composite packaging film is widely used in food packaging. Nylon packaging is widely used in the production of composite packaging films and also as a substrate for aluminum plated packaging films.
Nylon packaging film and its composite packaging film are mainly used for packaging greasy food, general food, frozen food, and steamed food. Untretched nylon packaging film, due to its high elongation rate, can be used for vacuum packaging of flavored meat, multi bone meat and other foods.
9. Ethylene vinyl alcohol copolymer packing film
EVAL packaging film is a new type of high barrier packaging film developed in recent years. It has good transparency, oxygen barrier, fragrance retention, and oil resistance. But its hygroscopicity is strong, which reduces its barrier properties after absorbing moisture.
EVAL packaging film is usually made into a composite packaging film together with moisture resistant materials, used for packaging meat products such as sausages, ham, and fast food. EVAL single film can also be used for packaging fiber products and woolen products.
10. Polyester packaging film is made of biaxially oriented polyester packaging film (BOPET).
PET packaging film is a type of packaging film with good performance. It has good transparency and luster; Has good air tightness and fragrance retention; Moderate moisture resistance, with a decrease in moisture permeability at low temperatures. The mechanical properties of PET packaging film are excellent, and its strength and toughness are the best among all thermoplastic plastics. Its tensile strength and impact strength are much higher than those of general packaging film; And it has good rigidity and stable size, suitable for secondary processing such as printing and paper bags. PET packaging film also has excellent heat and cold resistance, as well as good chemical and oil resistance. But it is not resistant to strong alkali; Easy to carry static electricity, there is no appropriate anti-static method yet, so attention should be paid when packaging powdered items.
The heat sealing of PET packaging film is extremely difficult and currently expensive, so it is rarely used in the form of a single film. Most of them are composite with PE or PP packaging film with good heat sealing properties or coated with polyvinylidene chloride. This composite packaging film based on PET packaging film is an ideal material for mechanized packaging operations and is widely used in food packaging such as steaming, baking, and freezing.
11. Polycarbonate packaging film
PC packaging film is odorless and non-toxic, with transparency and luster similar to glass paper, and its strength is comparable to PET packaging film and BONY packaging film, especially its outstanding impact resistance. PC packaging film has excellent fragrance retention, good air tightness and moisture resistance, and good UV resistance. It has good oil resistance; It also has good heat and cold resistance. Can be steamed and sterilized under high temperature and high pressure; Low temperature resistance and freezing resistance are better than PET packaging film. But its heat sealing performance is poor.
PC packaging film is an ideal food packaging material, which can be used for packaging steamed, frozen, and flavored foods. Currently, due to its high price, it is mainly used for packaging pharmaceutical tablets and sterile packaging.
12. Acetate cellulose packaging film
CA packaging film is transparent, glossy, and has a smooth surface. It is stiff, stable in size, not easy to accumulate electricity, and has good processability; Easy to bond and has good printability. And it has water resistance, folding resistance, and durability. The air permeability and moisture permeability of CA packaging film are relatively high, which can be used for “breathing” packaging of vegetables, fruits, and other items.
CA packaging film is commonly used as the outer layer of composite packaging film due to its good appearance and ease of printing. Its composite packaging film is widely used for packaging drugs, food, cosmetics and other items.
13. Ionic bonded polymer packaging film roll
The transparency and glossiness of ion bonded polymer packaging film are better than those of PE film, and it is non-toxic. It has good air tightness, softness, durability, puncture resistance, and oil resistance. Suitable for packaging of angular items and heat shrink packaging of food. Its low-temperature heat sealing performance is good, the heat sealing temperature range is wide, and the heat sealing performance is still good even with inclusions, so it is commonly used as a heat sealing layer for composite packaging films. In addition, ion bonded polymers have good thermal adhesion and can be co extruded with other plastics to produce composite packaging films.
Post time: Feb-11-2025