PC Resin Grades: Properties, Applications, and How to Choose the Right Grade

Learn about PC resin, its advantages in impact resistance and transparency, common applications, and key considerations when selecting a grade and processing the material.

What Is PC and What Grades Are Available?

PC stands for polycarbonate, an amorphous thermoplastic. It is widely considered for products that need a combination of transparency, impact resistance, and dimensional stability under heat. However, the name PC only identifies the polymer family; it does not indicate the flowability, transparency, or outdoor performance of a specific grade.

Commercial product lines include general-purpose, optical, UV-stabilized, flame-retardant, impact-modified, and glass-fiber-reinforced grades. Some formulations are no longer transparent. Therefore, first determine whether the product needs to provide clear visibility, diffuse light, or block visibility before selecting a grade and color.

Applications: Start with the Function of the Component

PC is used in lighting components, equipment housings, electronic parts, protective glazing, and many consumer products. For a lamp cover, the objective may be uniform light transmission; for a machine housing, the priority may be protecting internal components against impact. These two products require different sets of criteria.

Define requirements based on actual operating conditions: the height from which the product might fall, the heat sources it may encounter, the substances used to clean it, and whether it will be exposed to sunlight. This description is more useful than a general requirement such as “clear PC with good heat resistance” because it helps suppliers identify suitable material grades.

Reading the TDS: Flowability, Transparency, and Heat Resistance

MFR indicates mass flow rate, while MVR indicates volume flow rate. Comparisons must use the same test temperature, load, and units. A higher melt-flow value does not by itself prove that a material is stronger or will fill every mold successfully. Flow length, wall thickness, and gate location must also be considered.

Light transmittance and haze should be evaluated alongside sample thickness, color, and test method. For impact resistance, distinguish between notched and unnotched specimens and check the test temperature. HDT and Vicat measure different properties; neither should be treated as the product's continuous-use temperature.

Limitations to Check: Chemicals and Stress

PC's impact resistance does not mean that it can withstand every solvent. Chemicals, temperature, exposure time, and stress within a component can combine to cause cracking. A flat specimen immersed in a solution may perform differently from a machine housing that is fastened with screws or press-fitted into place.

When selecting a grade, test cleaning agents, oils and greases, adhesives, and other contacting materials on the assembled component. Record the commercial product name, concentration, number of cleaning cycles, and evaluation period. Do not inspect color alone; also check for fine cracks, clip strength, and drop performance after exposure.

Drying, Storage, and Processing Control

PC must be dried according to the specific grade's instructions before melting. Moisture can cause surface defects and polymer degradation. Drying time must suit the equipment and the condition of the resin; do not apply one temperature-and-time formula to every grade, particularly formulations containing special additives.

In production, record incoming moisture levels, the time the packaging was opened, actual melt temperature, and residence time. If silver streaks or reduced toughness occur, inspect the drying process, contamination, and thermal history. For regrind, separate materials by grade, color, and number of processing cycles, and validate the permitted proportion through testing.

Comparing PC with PMMA and PC Alloys

When comparing PC and PMMA, do not judge transparency by visual inspection alone. Prepare a requirements table covering impact resistance, surface quality, light transmission, operating environment, and finished-product cost, then compare specific grades of both materials. If the product requires a coating or surface treatment, test the complete material system.

PC alloys are blends based on PC. These materials may be suitable when a different balance of properties is required than conventional PC can provide, but their blend composition changes their performance. Do not replace one material with another simply because both product names contain “PC.”

Checklist Before Approving a Grade

A material-selection record should include the full grade designation and color code; the drawing and minimum wall thickness; optical requirements; actual loads and operating temperatures; contacting chemicals; outdoor exposure conditions; processing method; regrind limits; and the TDS and certification documents if required for the application.

After mold trials, retain reference samples along with dimensional, appearance, assembly, and functional test results. Select materials based on the proportion of conforming products and consistency between batches rather than price per kilogram alone. Repeat critical tests whenever the color or supplier changes.

Frequently Asked Questions About PC Resin

Is PC always transparent? No. Available grades include clear, translucent, opaque, reinforced, and modified materials. When ordering, specify the optical requirements and color code rather than only naming the polymer family.

Can flame-retardant PC be used for every electrical enclosure? The classification of the exact grade and color at the relevant thickness must be verified against the equipment requirements. The words “flame retardant” in a product description are not sufficient for design approval.

Why can a PC product still crack even when its TDS reports good impact strength? Possible causes include component geometry, assembly stress, chemical exposure, and processing conditions. Test the actual component before concluding that the resin itself is defective.

Find PC Resin Grades

See the list of PC resin grades below to compare manufacturers, specifications, and documentation for individual grades.

References

• Covestro — Overview of Makrolon Polycarbonate Grades

• Covestro — Makrolon 2405: Technical Data and Test Conditions

• Covestro — Makrolon: Chemical Resistance

• Covestro — Makrolon Product Range: Classification and Processing

This guide covers material selection at the polymer-family level. Before approving a specific grade, verify the current TDS, actual operating conditions, and test results obtained using the finished product.