PP: Polypropylene
It is a semi-bonded thermoplastic. It has high impact resistance, strong mechanical properties, resistance to a variety of organic solvents and acid and alkali corrosion. It is widely used in the industry and is one of the common polymer materials. Australian coins are also made of polypropylene.
OPP: Oriented polypropylene (film), stretchable polypropylene, is a kind of polypropylene.
OPP main products:
1, OPP tape: polypropylene film as the base material, with high tensile strength, light weight, non-toxic and tasteless, environmental protection, wide range of use and other advantages
2, OPP label: for the market is relatively saturated and homogenized daily chemical products, appearance is everything, the first glance impression determines the consumer’s purchase behavior. Shampoo, shower gel, detergent and other products are used in warm and humid bathrooms and kitchens, requiring the label to withstand moisture without falling off, its extrusion resistance must match the bottle body, and the transparent bottle body puts forward harsh requirements for the transparency of adhesives and label surface materials.
Compared with paper labels, OPP labels have the advantages of transparency, high strength, moisture-proof, and not easy to fall off. Although the cost has been increased, it can get a good label display and use effect. With the development of domestic printing process and coating technology, the production of self-adhesive film labels and printed film labels is no longer a problem, and it is foreseeable that the use of domestic OPP labels will continue to increase. Since the label itself is PP, it can be well combined with the surface of the PP/PE container, practice has proved that OPP film is the best material for the current in-mold label, which has been widely used in the European food and daily chemical fields, and gradually spread to the country, there are more and more users begin to pay attention to or adopt the in-mold labeling process.
opp is longitudinal stretching, bopp is both longitudinal and transverse stretching. This is related to the molecular structure, the polymer generally does not exist anisotropy, so there is no difference in the use of materials. There are some differences between unidirectional and bidirectional drawing. In the unidirectional drawing process, the injected film material enters the drawing unit composed of many rolls through the nozzle after forming, and the rolling speed is different. Therefore, the thickness of the film can be correspondingly changed with the change of the length. The tear strength of the film can be improved by one-way stretching, so the braided thread of ropes, packaging belts or bags is produced using this process. Thin films are produced in thicknesses between 25 and 800um. In bidirectional drawing, the film that has been prestretched longitudinally is stretched in an orthogonal direction with the same length as the extrusion direction. With the development of linear motors, the above stretching processes can be flexibly connected together and efficient forming of vertical and transverse bidirectional stretching is possible, which is the so-called “synchronous” stretching of bidirectional stretching, without complex transmission and chain structure. The manufacturer of this synchronous tensile device believes that the greater the uniformity of polymer stress, the higher the elastic coefficient, tear strength and tensile strength that can be conferred on the product.
Bidirectional drawing can also give the final product better uniformity and excellent transparency.
BOPP: BOPP is short for “Biaxially Oriented Polypropylene”, that is, biaxially drawn polypropylene film. It is also a type of polypropylene.
Commonly used BOPP films include: ordinary biaxial polypropylene film, heat seal biaxial polypropylene film, cigarette packaging film, biaxial polypropylene pearlized film, biaxial polypropylene metallized film, dull film, etc. Its production is the polymer polypropylene melt is first made into sheet or thick film through the narrow head, and then in the special drawing machine, at a certain temperature and set speed, at the same time or step in the vertical two directions (longitudinal, transverse) of the stretching, and through the appropriate cooling or heat treatment or special processing (such as corona, coating, etc.) made of film.
Commonly used BOPP films include: ordinary biaxial polypropylene film, heat seal biaxial polypropylene film, cigarette packaging film, biaxial polypropylene pearl-coated film, biaxial polypropylene metallized film, dull film, book film, laser molding film, anti-counterfeiting film and paper ball film.
The main uses of various films are as follows:
1, ordinary BOPP film use: mainly used for printing, bag making, adhesive tape and composite with other substrates.
2, BOPP heat sealing film use: mainly used for printing, bag making and so on.
3, BOPP cigarette packaging film use: for high-speed cigarette packaging.
4, BOPP pearl film use: used for printing food and daily necessities packaging.
5, BOPP metallized film use: used as vacuum gold plating, radiation, anti-counterfeiting substrate, food packaging.
6, BOPP extinction film use: for soap, food, cigarettes, cosmetics, pharmaceutical products and other packaging box.
7, BOPP anti-fog film use: used for vegetables, fruits, sushi, flowers and other packaging.
BOPP film is a very important flexible packaging material, which is widely used. BOPP film colorless, odorless, tasteless, non-toxic, and has high tensile strength, impact strength, rigidity, toughness and good transparency. The surface energy of BOPP film is low, and corona treatment is required before gluing or printing. However, after corona treatment, BOPP film has good printing adaptability, and can obtain exquisite appearance effect by color printing, so it is commonly used as the surface material of composite film. BOPP film also has shortcomings, such as easy to accumulate static electricity, no heat sealing and so on. In the high-speed production line, BOPP film is easy to generate static electricity, and an electrostatic remover is required. In order to obtain heat-sealable BOPP film, the surface of the BOPP film can be coated with heat-sealable resin adhesive after corona treatment, such as PVDC latex, EVA latex, etc., can also be coated with solvent adhesive, and can also be produced by extrusion coating or co-extrusion composite method. The film is widely used in the packaging of bread, clothes, shoes and socks, as well as the cover packaging of cigarettes and books. The initiation tear strength of BOPP film is increased after stretching, but the secondary tear strength is very low, therefore, the two ends of BOPP film can not leave any incision, otherwise the BOPP film is easy to tear during printing and composite. BOPP coated self-adhesive can produce sealing tape, is a large amount of BOPP market. BOPP film can be produced by tube film method or flat film method. The properties of BOPP films obtained by different processing methods are also different. The strength of BOPP film produced by flat film method is higher than that of tube film method because of its large tensile ratio (up to 8-10), and the uniformity of film thickness is also better. In order to obtain better comprehensive performance, the multi-layer composite method is usually used in the process of production. BOPP can be combined with a variety of different materials to meet specific application needs. For example, BOPP can be combined with LDPE(CPP), PE, PT, PO, PVA, etc., to obtain high gas resistance, moisture resistance, transparency, high temperature resistance, low temperature resistance, cooking resistance and oil resistance, and different composite films can be applied to oily food.
CPP: With good transparency, high gloss, good stiffness, good moisture resistance, excellent heat resistance, easy to heat seal and other characteristics.
CPP film is printed and bagged, suitable for: clothing, knitwear and flower bags; Film of documents and albums; Food packaging; And metallized film suitable for barrier packaging and decoration. Potential uses also include: food packaging, candy packaging (twist film), pharmaceutical packaging (infusion bag), in the fields of albums, folders and documents instead of PVC, synthetic paper, self-adhesive tape, name card holders, circular folders and standing bag composite materials.
CPP has excellent heat resistance. Since the softening point of PP is about 140, this film can be used in hot filling, cooking bags, aseptic packaging and other fields. Coupled with excellent acid, alkali and grease resistance, it becomes the preferred material in the field of bread product packaging or laminating materials. It is safe in contact with food, has excellent presentation performance, does not affect the flavor of the internal food, and can choose different grades of resin to obtain the desired characteristics.