How to Select an Impact Modifier for Low-Temperature PC

Start with the actual cold-impact requirement

Specify the failure being prevented and the temperature at which the part must pass. A -30°C notched Izod screen is not the same as a finished housing drop, assembly impact, puncture, instrumented impact or impact after thermal cycling. Record specimen geometry, notch preparation, conditioning, moisture, test speed and the required number of replicates. If the application is PC/ABS rather than PC, state the alloy composition and do not transfer a neat-PC result as a PC/ABS claim.

Low-temperature toughness is only one part of approval. Define room-temperature behavior, melt flow, tensile and flexural properties, heat resistance, appearance, color, hydrolysis or chemical exposure, flame requirements and dimensional limits. A modifier may improve the target impact response while changing stiffness, flow or heat performance. The evaluation plan must preserve the full property window rather than optimizing one number in isolation.

Understand the published RC-721 evidence

RC-721 is an MBS core-shell impact modifier for PC and PC/ABS evaluation. The published PC dataset uses PC-110 / RC-721 = 95 / 5 and reports 745 J/m at 23°C and 648 J/m at -30°C. The page also publishes same-formulation comparisons with RC-701 and RC-732, plus a separate controlled PC/ABS dataset. Those values are application-test results for the stated formulation, not guaranteed product specifications or a universal recommendation of five percent.

RC-721 is positioned as a comparable grade for evaluation against Kaneka M-721. That relationship is useful for buyers who currently use the reference grade, but it does not establish chemical identity, an exact replacement or permission to skip qualification. The approved sample, trial record, commercial order and batch COA should all identify RC-721 and the relevant lot.

Understand the published RC-756 evidence

RC-756 is a silicone-rubber-core impact modifier positioned for low-temperature impact and hydrolysis-resistance-focused evaluation in PC and PC/ABS. Its published controlled PC formulation is PC / RC-756 / PETS / 1010 = 95 / 5 / 0.5 / 0.5, with reported Izod values of 778 J/m at 23°C and 685 J/m at -30°C. Because this formulation contains additional components and differs from the RC-721 test, the numbers must not be used as a direct ranking between the two grades.

Mitsubishi S-2501 and Kaneka MR-502 appear only as evaluation context for RC-756; a direct controlled comparative dataset is not currently published. The correct status is therefore requires customer validation. Request the current grade-specific TDS and available technical documents rather than inferring a specification from another modifier family.

Run a fair low-temperature trial

• Use one PC lot, one drying protocol and the same complete additive package for every candidate condition.
• Create a control and a supplier-agreed dosage ladder; do not assume that the published five-percent application test is the optimum for the customer’s resin.
• Hold extrusion residence time, melt temperature, screw configuration, pellet conditioning, molding settings and specimen preparation constant.
• Condition specimens to the required temperature for a documented time and test enough replicates to understand scatter and failure mode.
• Measure room-temperature impact, low-temperature impact, flow, heat and mechanical retention together, then confirm the preferred condition on representative parts.

Qualification and procurement closeout

Repeat the preferred trial and compare more than one commercial-representative lot when the application risk warrants it. Link each sample to grade, batch, bag label, TDS and COA. Agree incoming checks, retained samples and advance change notification before switching a production formulation. If hydrolysis resistance or another exposure claim matters, define and run the customer’s own exposure method; positioning language is not finished-part proof.

After technical approval, request the current grade-specific quotation. RC-721 public pricing may be shown as a weekly indicative range, while RC-756 may be price on request depending on current D1 status. All displayed figures are reference only. Final product price, freight, insurance and CIF require manual confirmation for the shipment. A 5 kg free sample with customer-paid sample freight is the published engineering-modifier term, subject to current grade and destination confirmation.

Products for Evaluation and D1 Price Status

Reference price range only. Actual price depends on grade, quantity, destination and current market conditions. Please contact us for today's confirmed CIF quotation.

Controlled Evidence and Related Resources

Frequently Asked Questions