BOPP Film: Characteristics of Raw Materials
Biaxially Oriented Polypropylene (BOPP) film possesses exceptional properties including high strength, superior gas barrier characteristics, excellent printability, and tear resistance. It stands out as the most utilized type within the spectrum of PP film products, boasting widespread applications. ExxonMobil, a prominent producer, annually manufactures over 2 million tons of BOPP films, offering a diverse range comprising nearly 40 varieties tailored to various application domains.
- Key Properties of Polypropylene Resin and Measurement Techniques
Polypropylene, abbreviated as PP, undergoes partial crystallization through the polymerization of propylene monomer. Four primary polymerization methods—solution, solvent slurry, liquid phase bulk, and gas phase—yield polypropylene resin with varied properties. Among these, melt mass flow rate (MFR) and stereoisotacticity stand as crucial parameters.
- Melt Flow Rate (MFR): MFR measures the mass of thermoplastic material passing through a standard die in 10 minutes under specified temperature and pressure conditions, denoted in g/10min. It is a crucial indicator of polypropylene's flow characteristics during processing, with a direct correlation to polymer molecular weight and viscosity. MFR evaluation typically involves an extrusion plastometer.
- Stereoregularity (Isotacticity): Isotacticity denotes the proportion of regular isomers within the polymer structure. This parameter, vital in delineating polypropylene's properties, primarily depends on the percentage of isotactic structure molecules within the homopolymer. Isotacticity assessment often utilizes extraction methods due to the solubility characteristics of the isomer.
- Molecular Weight and Distribution: Molecular weight, the sum of relative atomic masses in a chemical formula, and molecular weight distribution, represented by the distribution coefficient, signify the spread around the average molecular weight. Determination techniques encompass various methods such as end group analysis, solution colligative methods, and viscosity methods, chosen according to the molecular weight range. Accurate depiction of polymer molecular weight necessitates consideration of both statistical average and distribution.
- Particle Appearance: Evaluation of particle appearance involves scrutiny for deviations such as black particles, colored particles, impurities, etc., against predefined criteria. This assessment typically involves screening resin pellets through sieves and visual inspection.
- Powder Ash: Powder ash content quantifies residual catalyst and other substances in the resin. It is measured by determining the residual inorganic ash content post-calcination of polypropylene particles at 850°C.
- Crystallinity: Crystallinity, expressing the mass of crystalline segments as a percentage of the total mass, is commonly analyzed qualitatively using data from diffractometers.
- Tensile Strength: Tensile strength denotes the maximum stress a material can endure before experiencing uniform plastic deformation under specific environmental conditions. It is determined through fracture experiments conducted on polypropylene sheets using a tensile testing machine.
- Introduction to Differentiated BOPP Film Varieties
BOPP film varieties encompass a diverse array catering to specific applications, including:
- BOPP Laser Film
- BOPP High Temperature Transfer Film
- BOPP Low Temperature Transfer Film
- BOPP Single and Double-Sided Heat Sealing Film
- BOPP Matte Film
- BOPP Standard Smoke Film
- BOPP High Gloss Shrink Smoke Film
- BOPP Anti-Wear Pattern Smoke Film
- BOPP Anti-Red and Anti-Wrinkle Cigarette Film
- BOPP Medium-Shrink and Low-Shrink Cigarette Film
- BOPP Heat-Sealing Type Wire Film
- BOPP Light Film Type Wire Film
- BOPP Flat Mold (Tape Film, Bag Making Film, Printing Film, etc.)
- BOPP Pearlescent Film
- BOPP Synthetic Paper
- BOPP Pre-Coated Film
- BOPP Aluminum Coating
