Profile Extrusion: Resin Processing Parameters
Processing Bayer resins on extrusion lines requires an understanding of equipment settings as well as the properties of the specific resin. The following sections give an overview of the processing parameters for commonly used Bayer products in each of the three lines available for profile extrusion. Keep in mind that processing parameters can vary considerably, depending on the product to be manufactured and the plant technology available.
You can find more information about most grades and standard values in Bayer product information bulletins. See http://www.bayermaterialsciencenafta.com/products/index.cfm.
Moisture Content
Moisture in polycarbonate based resins can adversely affect processing and the quality of sheet. Manage moisture levels for all types of Bayer resins so the recommended moisture content of a specific resin is not exceeded. Drying is required prior to processing using dehumidifying or vacuum dryers. Hot air dryers will prolong drying times. Maintain specific drying temperatures and times during pre-drying. If the resin is not pre-dried, it may be degassed using vacuum during extrusion.
Bayer recommends a moisture level of 0.02% or less for all extrusion products. A slightly higher moisture level is acceptable if a vacuum vented extruder is used. Undried polymer can be processed with a well maitained, double-vented extruder,though this must be closely monitored, and may not be effective with unusually wet polymer.
Please refer to the individual product information bulletins available for each grade for specific drying conditions.
Makrolon® Polycarbonates
For Makrolon® grades, use the following processing parameters for the extruder, co-extruder, and sizing unit. Depending on the product to be manufactured or the plant technology, processing parameters may vary considerably.
Extruder Temperatures
Depending on the grade, the melt temperature should be between 465°F to 520°F (240°C and 270°C). A decreasing temperature profile from the feed hopper to the screw tip gives good results.Use the following barrel and die temperature settings as a guide.
Table 1. Profile extruder temperatures for Makrolon® polycarbonates Extruder Component Recommended Temperatures Feed section 520°F to 555°F (270°C to 290°C) Compression section 480°F to 520°F (250°C to 270°C) Metering section 465°F to 500°F (240°C to 260°C) Die 465°F to 500°F (240°C to 260°C) Overheating and excessively long residence times should be avoided, as these conditions can lead to discoloration and material degradation.
Coextruder Temperatures
When coextruding a Makrolon® polycarbonate with an ultra-violet (UV) concentrate, the melt temperature of the UV resin should be approximately 68ºF (20°C) lower than that of the base resin. The barrel temperatures of the coextruder must be adjusted accordingly.Sizing Unit Temperatures
The sizing unit temperature should be between 105°F and 212°F (40°C and 100°C) to avoid stress cracking.
Bayblend® Polycarbonate/Styrenic Alloys
For Bayblend® ET1000 alloy (a standard grade for profile extrusion), use the following processing parameters. Depending on the product to be manufactured or the plant technology, processing parameters may vary considerably.
Extruder Temperatures
The extruder should be set to yield a maximum melt temperature of 520°F (270°C). Use the following barrel and die temperatures as a guide for processing other Bayblend® grades.
Table 2. Extruder temperatures for processing Bayblend® ET1000 Extruder Component Recommended Temperatures Section 1 420°F to 440°F (215°F to 225°C) Section 2 440°F to 460°F (225°F to 240°C) Section 3 440°F to 470°F (225°F to 245°C) Section 4 440°F to 480°F (225°F to 250°C) Die 440°F to 480°F (225°F to 250°C) Overheating and excessively long residence times should be avoided, as these conditions may lead to discoloration and material degradation.
Downstream Unit Temperatures
Temperatures of units downstream from the extruder, such as the screen exchanger, melt pump, co-extruder adapter, and sheet extrusion die, should match the temperature of the last barrel zone.Calibrator Temperature
The temperature range for any type of calibrator should be 60°F to 160°F (15°C to 70°C).
The type of calibrator (low-friction calibrator, vacuum tank calibrator, or draw plate calibrator) that is appropriate for your application depends on the geometry of the profile.
Makroblend® Polycarbonate/Polyester Alloys
For Makroblend® EC 100 MT alloy, use the following processing parameters. Specific processing conditions will depend on the sheet being produced and the production technology available.
Extruder Temperatures
The extruder should be set to yield a maximum melt temperature of 545°F (285°C). Use the following barrel and die temperatures as a guide for processing other grades.
| Table 3. Profile extruder temperatures for Makroblend® EC 100 MT alloy | |
| Extruder Component | Recommended Temperatures |
| Section 1 | 480°F to 500°F (250°C to 260°C) |
| Section 2 | 480°F to 500°F (250°C to 260°C) |
| Section 3 | 500°F to 520°F (260°C to 270°C) |
| Section 4 | 500°F to 520°F (260°C to 270°C) |
| Die | 520°F to 530°F (270°C to 275°C) |
Overheating and excessively long residence times should be avoided, as these conditions may lead to discoloration and material degradation.
Downstream Unit Temperatures
Temperatures of units downstream from the extruder, such as the screen exchanger, melt pump, co-extruder adapter, and sheet extrusion die, should match the temperature of the last barrel zone.
you have any questions about using Bayer resins on your extrusion equipment, you can reach the technical team at BMS using the Contact form.
