PE/PP/PVC/PS/PE/PC and other 9 kinds of functional film materials performance and use of checkThere are many kinds of plastic films with different characteristics, which are widely used, and according to the different characteristics of the film, its use is also different. So, do you know the types and uses of plastic film? In this article, Xiaobian will introduce you to some common plastic film basic characteristics, applications, let's take a look.
1） PE polyethylene film PE film is a large use of plastic packaging film, accounting for about 40% of the total consumption of plastic film. Although PE film is not very ideal in terms of appearance and strength, it has good toughness, moisture resistance and heat sealing performance, and it is convenient to process and form, and the price is cheap, so it is widely used. LDPE film Low density polyethylene film (LDPE film) is mainly produced by extrusion blow molding and tape casting method. The thickness of cast polyethylene film is uniform, but due to the high price, it is rarely used at present. Blow molded LDPE film is a flexible and transparent film, non-toxic, odorless, the thickness is generally between 0.02 and 0.1mm. It has good water resistance, moisture resistance, drought resistance and chemical stability. It is widely used in general moisture-proof packaging and frozen food packaging for food, medicine, daily necessities and metal products. However, for items with large moisture absorption and higher moisture resistance requirements, it is necessary to use films and composite films with better moisture resistance. LDPE film has high permeability, no fragrance preservation and poor oil resistance, and can not be used for the packaging of easily oxidized food, flavored food and oily food. However, good air permeability makes it can be used for fresh packaging of fruits, vegetables and other fresh items. LDPE film has good thermal adhesion and low temperature thermal sealing, so it is commonly used as the adhesive layer and heat sealing layer of composite film, but because of its poor heat resistance, it can not be used as the heat sealing layer of cooking bag. HDPE film
High density polyethylene film (HDPE film) is a kind of flexible translucent film, its appearance is milky white, the surface gloss is poor. The tensile strength, moisture resistance, heat resistance, oil resistance and chemical stability of HDPE film are better than LDPE film, and can also be heat-sealed, but the transparency is not as good as LDPE. HDPE can be made into a thickness of 0.01mm film, its appearance is very similar to thin silk paper, feel comfortable, also known as pseudo-paper film. It has good strength, toughness and opening, in order to enhance the feeling of paper and reduce the cost, a small amount of light calcium carbonate can be added. HDPE paper film is mainly used to make various shopping bags, garbage bags, fruit bags and various food bags. Because of its poor air tightness and lack of fragrance preservation, the storage period of packaged food is not long. In addition, HDPE film can be used as the heat sealing layer of cooking bag because of its good heat resistance. 2）PP polypropylene film PP film is divided into unstretched film and bidirectional stretched film, the two films are very different in performance, so it should be considered as two different films.
Unstretched polypropylene film
Unstretched polypropylene films include blown polypropylene film (IPP) produced by extrusion blow molding and extruded cast polypropylene film (CPP). The transparency and toughness of IPP film are poor. CPP film has better transparency and gloss, and its appearance is close to cellophane. Compared with PE film, unstretched polypropylene film has better transparency, gloss, moisture resistance, heat resistance and oil resistance. High mechanical strength, tear resistance, puncture resistance and wear resistance; And non-toxic, odorless. Therefore, it is widely used in the packaging of food, medicine, textiles and other items. However, its drought resistance is poor, and it is brittle at 0-10 ° C, so it can not be used for frozen food packaging. Unstretched polypropylene film has high heat resistance temperature and good heat sealing performance, so it is commonly used as the heat sealing layer of cooking bag. Biaxially stretched polypropylene film
BOPP film has the following characteristics: transparency, gloss, comparable to cellophane; The mechanical strength increases, but the elongation decreases. The cold resistance is improved, and the brittleness is not changed when used at -30 ~ -50℃; The moisture permeability and air permeability are reduced by about half, and the organic vapor permeability is also reduced to different degrees. The single film cannot be heat-sealed directly, but its heat-sealing property can be improved by coating adhesives with other plastic films. BOPP film is a new type of packaging film developed for the purpose of replacing cellophane, and its price is about 20% lower than cellophane. Therefore, cellophane has been replaced or partially replaced in food, medicine, cigarettes, textiles and other packaging. But its resilience is large, can not be used for candy kink packaging. 3) PVC polyvinyl chloride film PVC film is divided into soft film and hard film The elongation, tear strength and cold resistance of soft PVC film are good. Easy to print and heat seal; It can be made into transparent film. Because the soft PVC film has the odor of plasticizer, and there are problems such as plasticizer migration, it is generally not used for food packaging. However, the soft PVC film produced by the internal plasticizing method can be used for packaging food. In general, PVC soft film is mainly used for industrial products and non-food packaging.
Rigid PVC film, commonly known as PVC cellophane. High transparency, crisp, toughness, kink stability; It has good air tightness, fragrance preservation and better moisture resistance. Excellent printing performance, can produce non-toxic film. It is mainly used in the kink packaging of sweets, the packaging of textiles, clothing, and the outsourcing film of cigarettes and food packaging boxes. However, the cold resistance of rigid PVC is poor, and it is brittle at low temperature, so it is not suitable for frozen food packaging materials. 4)PS polystyrene film PS film has high transparency and gloss, beautiful appearance, good printing performance; Low water absorption, high transmittance to gas and water vapor. Unstretched polystyrene films are hard and brittle, and their extensibility, tensile strength and impact strength are low, so they are rarely used as flexible packaging materials. The main products used in packaging are bidirectional stretched polystyrene (BOPS) films and heat absorption films. The good breathability of BOPS film makes it suitable for packaging fresh foods such as fruits, vegetables, meat and fish, as well as flowers. 5） PVA polyvinyl alcohol film Optical grade PVA film, full name of polyvinyl alcohol film, is the core film material of polarizer. At present, the global optic-grade PVA film market is basically monopolized by two companies, Japan Cololi and Synthetic Chemistry. With the continuous expansion of the production scale of liquid crystal displays, the consumption of optical-grade PVA films in China has increased rapidly. However, due to the high technical barriers of optically grade PVA film, the domestic has not yet completely broken through, there are only two enterprises with production strength, more than 90% of optically grade PVA film still needs to be imported, and the future of domestic material replacement space is huge. 6）PA nylon film Nylon film is a very tough film, non-toxic and tasteless, good transparency, luster, not easy to accumulate static electricity, good printing performance. Its mechanical strength is high, tensile strength is three times that of PE film, wear resistance, puncture resistance is excellent. Nylon film has good heat resistance, sweat resistance and oil resistance, but it is difficult to heat seal. In the dry state, nylon film has good air tightness, but its moisture permeability is large and water absorption is strong. In the high humidity environment, the dimensional stability is poor, and the air tightness decreases sharply. Therefore, polyvinylidene chloride coating (called KNY) or composite with PE film is often used to improve its water resistance, moisture resistance and heat sealing performance. This NY/PE composite film is widely used in food packaging. Nylon packaging is widely used to make composite films and is also used as a substrate for aluminized films. 7） PET Polyester film PET film is a kind of packaging film with good performance. Its transparency is good, shiny; It has good air tightness and fragrance preservation. The moisture resistance is moderate, and the moisture permeability decreases at low temperature. The mechanical properties of PET film are excellent, its strength and toughness are good in all thermoplastics, and the tensile strength and impact strength are much higher than the general film; And good strength, stable size, suitable for printing, paper bags and other secondary processing. PET film also has excellent heat and cold resistance and good chemical resistance and oil resistance. But it is not resistant to strong alkali; It is easy to carry static electricity, and there is no appropriate anti-static method, so attention should be paid to the packaging of powdered items. PET film heat sealing is extremely difficult, the current price is also high, so it is rarely used in the form of a single film, mostly with good heat sealing PE or PP film composite or the use of polyvinylidene chloride coating. 8) PC polycarboate film PC film is odorless, non-toxic, similar to cellophane transparency and luster, and the strength is comparable to PET film and BONY film, especially the impact strength is very outstanding. PC film has excellent fragrance preservation, good air tightness and moisture resistance, and has a better ability to prevent ultraviolet light transmission. Its oil resistance is good; Heat and cold resistance is also very good. Can be cooked under high temperature and high pressure sterilization; Low temperature resistance and freezing resistance are better than PET film. But its heat sealing property is poor. 9) CA cellulose acetate film CA film transparent, glossy, smooth surface. Its rigidity, stable size, not easy to accumulate electricity, good processability; Easy to glue, printing is also very good. And has water resistance, folding resistance and durability. The air permeability and moisture permeability of CA film are large, and this feature can be used for "breathing" packaging such as vegetables and fruits. CA film is commonly used as the outer layer of composite film because of its good appearance and easy printing. Its composite film is widely used in the packaging of drugs, food, cosmetics and other items. |
