1. Extrusion: The grade used for extrusion production generally has a melt index less than 1 and a medium to wide MWD. During processing, low MI can obtain suitable melt strength. Wider MWD grades are more suitable for extrusion because they have higher production speeds, lower die pressures and reduced melt fracture tendency.
2. Blow molding: The characteristic indicators of blow molding grades, such as melt strength, ES-CR and toughness, are similar to those used for sheet and thermoforming applications, so similar grades can be used. Injection-blow molding is usually used to make smaller containers (less than 16oz) for packaging medicines, shampoos and cosmetics. One of the advantages of this process is that the production bottle is automatically trimmed, without the need for post-finishing steps like general blow molding. Although there are some narrow MWD grades used to improve surface finish, medium to wide MWD grades are generally used.
3. Injection molding: injection molding grades generally have a melt index of 5 to 10, and there are grades with toughness and lower fluidity and higher fluidity grades with processability. Uses include daily necessities and food thin-walled packaging; tough, durable food and paint cans; high resistance to environmental stress cracking applications, such as small engine fuel tanks and 90-gal garbage cans.