DuPont Pyralux AP9232R: 2 oz copper / 3 mil polyimide flex laminate review covering specs, current capacity, thermal benefits, applications & fabrication tips.
Most flex laminate discussions default to 1 oz copper because that’s what works for signal routing, fine-line imaging, and dynamic flex zones. But when the design demands high current, aggressive thermal dissipation, or power distribution on a flex or rigid-flex board, the 1 oz conversation ends quickly. That’s where the DuPont Pyralux AP9232R enters โ a double-sided, 2 oz rolled-annealed copper construction on a 3 mil all-polyimide dielectric that is purpose-built for exactly those demanding power and thermal scenarios.
What the DuPont Pyralux AP9232R Product Code Tells You
The AP prefix identifies this as the all-polyimide, adhesiveless Pyralux family. No acrylic or epoxy bonding layer sits between the copper and the polyimide dielectric โ the defining structural difference from older three-layer flex laminates.
The digits 9232 follow the AP series naming convention: the first digit (9) is the series identifier, the second digit (2) represents 2 oz (70 ยตm) copper, the third digit (3) represents 3 mil (75 ยตm) dielectric thickness, and the fourth digit (2) represents 2 oz copper on the second side. The trailing R designates rolled-annealed (RA) foil. In plain construction terms: 2 oz RA copper / 3 mil polyimide / 2 oz RA copper โ a symmetric, double-sided, adhesiveless laminate with heavier copper on both sides.
DuPont Pyralux AP9232R: Core Specifications
Table 1 โ AP9232R Construction Summary
| Parameter | Value |
| Product Series | Pyralux AP (All-Polyimide) |
| Construction Type | Adhesiveless, double-sided copper-clad |
| Dielectric Thickness | 3 mil / 75 ยตm |
| Copper Thickness (both sides) | 2 oz / 70 ยตm |
| Copper Foil Type | Rolled-Annealed (RA) |
| Glass Transition Temperature (Tg) | 220ยฐC |
| Maximum Operating Temperature | 180ยฐC (356ยฐF) |
| IPC Certification | IPC-4204/11 |
| UL Flammability Rating | UL 94V-0 |
| Quality System | ISO 9001:2015 |
Table 2 โ AP9232R Electrical Properties
| Property | Typical Value | Test Method |
| Dielectric Constant (Dk) @ 1 MHz | 3.4 | IPC-TM-650 2.5.5.3 |
| Dielectric Constant (Dk) @ 10 GHz | 3.2 | IPC-TM-650 2.5.5.3 |
| Dissipation Factor (Df) @ 1 MHz | 0.002 | IPC-TM-650 2.5.5.3 |
| Dielectric Strength | 200 kV/mm (4.9 kV/mil) | ASTM D-149 |
| Volume Resistivity (damp heat) | 10ยนโฐ Mฮฉ | IPC-TM-650 2.5.17.1 |
| Surface Resistance (damp heat) | 10โถ Mฮฉ | IPC-TM-650 2.5.17.1 |
Table 3 โ AP9232R Thermal and Mechanical Properties
| Property | Value |
| Solder Float @ 288ยฐC (550ยฐF) | Passes |
| Dimensional Stability (Method B) | โค ยฑ0.05% |
| Dielectric Thickness Tolerance | ยฑ10% |
| Moisture Absorption | ~0.94% |
| CTE (in-plane) | Low (matched for rigid-flex multilayer) |
| Continuous Use Temperature | 180ยฐC (356ยฐF) |
The 2 oz Copper Advantage: Why Heavier Copper Changes the Design Equation
Current Carrying Capacity: The Numbers That Matter
A 2 oz copper trace can carry approximately twice the current of a 1 oz trace for the same width and temperature rise, consistent with IPC-2221 industry methodology. For a designer targeting tight real estate on a power flex board, that halving of required trace width isn’t academic โ it’s the difference between a flex circuit that fits the design envelope and one that doesn’t.
Table 4 โ Approximate Current Capacity for 2 oz RA Copper Traces (10ยฐC Temperature Rise)
| Trace Width | Estimated Current (External Layer) | Estimated Current (Internal Layer) |
| 20 mil (0.5 mm) | ~2.6 A | ~1.3 A |
| 50 mil (1.27 mm) | ~5.2 A | ~2.6 A |
| 100 mil (2.54 mm) | ~8.5 A | ~4.3 A |
| 200 mil (5.08 mm) | ~14 A | ~7 A |
Guidelines per IPC-2221 at 10ยฐC rise. Add 20โ30% margin for production designs.
Thermal Management: The Embedded Heat Spreader Effect
Copper’s thermal conductivity of approximately 400 W/mยทK makes it an effective heat spreader. In power electronics where components dissipate significant heat, 2 oz copper can reduce operating temperatures by 10โ20ยฐC compared to equivalent 1 oz designs. The AP9232R copper planes aren’t just electrical conductors โ they function as embedded heat spreaders, conducting heat laterally before it accumulates under sensitive components. In a rigid-flex stackup with AP9232R as the flex core, thermal vias channel that heat further into rigid sections or to an external heatsink.
Voltage Drop and Power Integrity
The lower resistance in 2 oz copper traces means less voltage drop across power distribution rails โ critical in applications with tight voltage regulation requirements. On a flex circuit routing a 3.3V or 1.8V power rail across a long flex tail to a remote processor subsystem, the resistance reduction from 2 oz copper is directly visible in PDN simulation results.
Why the 3 Mil Dielectric Pairs Well With 2 Oz Copper
The 3 mil dielectric thickness is a deliberate design choice that works in favor of power and thermal applications in specific ways.
Thinner dielectric improves thermal coupling. In rigid-flex assemblies bonded to heat-sinking structures, a thinner polyimide layer between the copper and the bonded heatsink reduces thermal resistance. Keeping polyimide thickness at 3 mils rather than 4 or 5 mils measurably reduces the thermal impedance to external cooling hardware.
Mechanical stiffness contribution. The combination of 2 oz copper (70 ยตm) and 3 mil (75 ยตm) dielectric creates a laminate where copper and polyimide thicknesses are nearly equal. This construction is stiffer than thinner AP grades โ generally desirable for power flex circuits occupying semi-static or rigid-flex segments rather than high-cycle dynamic flex areas.
Signal layer coexistence. Power flex circuits often still carry controlled impedance signals on adjacent layers. With Dk of 3.4 and a 3 mil dielectric, AP9232R remains well within the range that supports practical controlled impedance design for signal layers in the same stackup.
DuPont Pyralux AP9232R Versus Related AP Series Grades
Table 5 โ Pyralux AP Series Comparison: Heavy vs. Standard Copper Grades
| Product Code | Dielectric (mil) | Copper (oz, both sides) | Copper Type | Best Use Case |
| AP9131R | 3 mil | 1 oz / 1 oz | RA | Signal flex, dynamic flex zones |
| AP9232R | 3 mil | 2 oz / 2 oz | RA | Power flex, high-current, thermal management |
| AP9141R | 4 mil | 1 oz / 1 oz | RA | Controlled impedance, multilayer rigid-flex |
| AP9242R | 4 mil | 2 oz / 2 oz | RA | Heavy copper at thicker dielectric |
| AP9151R | 5 mil | 1 oz / 1 oz | RA | High layer count rigid-flex stackups |
The key distinction between AP9232R and AP9131R is purely copper weight โ both share the same 3 mil all-polyimide dielectric. A common mixed-construction approach on power-heavy rigid-flex designs: specify AP9232R for power layer cores and AP9131R or AP9141R for signal layer cores within the same multilayer stackup.
All-Polyimide Construction: Why It Matters Specifically for Power Applications
No adhesive thermal boundary. Conventional three-layer flex laminates use acrylic or epoxy adhesive to bond copper to polyimide film. That adhesive layer has lower thermal conductivity than either the copper or the polyimide, creating a thermal bottleneck in the stack. AP9232R eliminates this layer โ copper bonds directly to the polyimide, removing one thermal resistance layer from the heat path.
Thermal stability at 180ยฐC continuous use. At sustained 180ยฐC operation โ common in automotive under-hood power electronics or industrial motor controllers โ adhesive-based laminates frequently show creep and delamination. AP9232R’s all-polyimide construction has no adhesive to degrade under these conditions.
Process compatibility for power board fabrication. DuPont Pyralux AP double-sided copper-clad laminates are fully compatible with all conventional flexible circuit fabrication processes, including oxide treatment and wet chemical plated-through-hole desmearing. Fabricated circuits can be covercoated and laminated together to form multilayers or bonded to heat sinks using polyimide, acrylic, or epoxy adhesives.
Applications Where DuPont Pyralux AP9232R Is the Right Call
Automotive Power Electronics
Under-hood electronics โ ECUs, power distribution modules, DC-DC converters, and motor inverters โ face simultaneous demands for high current capacity, wide thermal cycling range (-40ยฐC to +125ยฐC or higher), and chemical resistance. AP9232R brings 2 oz copper benefits into a flex laminate platform, enabling power distribution circuits to conform to the mechanical envelope of under-hood assemblies.
Industrial Motor Controllers and Variable Frequency Drives
Motor phase current outputs in VFD designs commonly range from 10 A to over 100 A at the power stage level. At the flex interconnect between power stage and control circuitry, 2 oz RA copper on AP9232R provides the current density and thermal headroom that 1 oz constructions simply cannot match within the same trace real estate.
Aerospace and Satellite Power Distribution
DuPont Pyralux AP is available in copper thicknesses of 6, 9, 12, 18, 35, and 70 microns, giving aerospace program managers the flexibility to specify the exact copper weight needed for weight-optimised power distribution harnesses. AP9232R’s 180ยฐC thermal tolerance, UL 94V-0 flammability rating, and available NASA outgassing data make it viable for primary power distribution flex in space hardware.
LED Driver and High-Power Lighting Boards
High-power LED arrays generate significant junction heat that must be conducted away through the board. A flex board using AP9232R bonded to a metal backing provides both the electrical interconnect and the thermal path in a single laminate โ replacing heavier separate assemblies of metal-core PCBs and flex tails.
For design teams working with DuPont PCB materials on power-heavy flex projects, the AP9232R is frequently the material that opens the “2 oz flex” conversation before considering whether even heavier copper grades are warranted.
Fabrication Considerations for AP9232R
Etch factor management. At 70 ยตm copper thickness, undercut during subtractive etching is more pronounced than at 35 ยตm. Confirm etch compensation factors with your fabricator before releasing artwork โ even on power circuits with wide traces, this prevents dimensional surprises at first article.
Minimum bend radius. With 2 oz RA copper, the minimum bend radius is significantly larger than for 1 oz AP constructions. Calculate the bend radius using the total stack thickness including both 70 ยตm copper layers, and plan flex zone length accordingly before finalizing the mechanical design.
Coverlay registration. Coverlay films over 2 oz copper traces must bridge a larger step height between trace surfaces and the surrounding dielectric. Confirm your fabricator’s coverlay capability for 2 oz copper before specifying tight trace spacing in covered areas.
Soldering thermal mass. Thicker copper adds significant thermal mass at solder joints. Adjust reflow profiles to account for the increased heat absorption, and ensure rework operators are briefed on higher iron temperature and dwell time requirements.
Drilling and desmear. Plated through holes in 2 oz copper constructions require consistent drill entry conditions and robust wet chemical desmear. Copper stub management and drill stack height planning are more critical at 2 oz than at standard 1 oz weights.
Useful Resources for DuPont Pyralux AP9232R
Table 6 โ Key Reference Resources
| Resource | Description | URL |
| DuPont Pyralux AP Official Page | Product overview, features, construction tables | dupont.com/electronics-industrial/pyralux-ap.html |
| Pyralux AP Technical Data Sheet (PDF) | Full material properties, test methods, product selection | pyralux.dupont.com |
| Cirtech Electronics โ Pyralux AP Series | Distributor listing with AP9232R and related grades | cirtech-electronics.com/series/pyralux-ap |
| IPC-4204/11 Standard | Certification standard for flexible metal-clad dielectrics | ipc.org |
| IPC-2221 Design Standard | PCB design guidelines including trace current capacity tables | ipc.org |
| NASA Outgassing Database | Verified outgassing data for space-rated material qualification | outgassing.nasa.gov |
| DuPont Pyralux Safe Handling Guide | Handling, storage, and lamination process guidance | pyralux.dupont.com |
Frequently Asked Questions About DuPont Pyralux AP9232R
Is AP9232R suitable for dynamic flex (repeated bending in service)?
The RA copper foil makes AP9232R more capable of dynamic flex than an equivalent ED copper construction, but the 2 oz copper weight significantly increases laminate stiffness and raises minimum bend radius requirements. For very high cycle count dynamic flex zones (tens of thousands of cycles), a thinner AP grade โ such as AP9121R at 2 mil or AP9131R at 3 mil with 1 oz copper โ is a better fit. AP9232R is most appropriate for semi-static or one-time fold zones and for the power distribution segments of a rigid-flex assembly.
How does AP9232R perform in rigid-flex multilayer stackups?
It performs well as a power layer core within a rigid-flex multilayer. DuPont Pyralux AP Double-side Clad is manufactured under a certified ISO 9001:2015 Quality Management System facility, with complete material and manufacturing records maintained by DuPont and each manufactured lot identified for reference traceability. The all-polyimide, low-CTE construction is well-matched to the polyimide bondplies used to join flex cores and to the rigid sections of rigid-flex assemblies.
What is the cost premium of AP9232R versus 1 oz AP equivalents?
Expect a meaningful cost premium. Higher copper content drives raw material cost, and 2 oz copper processing โ etching, coverlay, plating โ is more demanding than standard 1 oz fabrication. At the system level, that premium is often recovered: routing more current through a compact flex circuit with AP9232R can eliminate separate wire harness segments or heavier rigid power boards, reducing total BOM and assembly labor costs.
What coverlay should be used with AP9232R?
Standard Pyralux coverlay products are compatible with AP series laminates including AP9232R. For power circuits, coverlay is preferred over LPI solder mask in flex zones for better adhesion and flexibility. For power pads and heat-sinking areas, selectively opening the coverlay to expose bare copper planes for heatsink bonding is a common and proven approach.
Does AP9232R meet aerospace outgassing requirements?
DuPont maintains outgassing data for the Pyralux AP series relevant to NASA low-outgassing requirements. The all-polyimide construction โ without the adhesive layer present in conventional three-layer laminates โ generally performs well on outgassing criteria. For specific programs requiring documented ASTM E595 data, check the NASA outgassing database directly or request data from DuPont through their authorized representatives.
Final Assessment: When AP9232R Is the Right Choice
The DuPont Pyralux AP9232R fills a specific but important niche: it is the AP series grade you reach for when your flex circuit design is driven by current capacity and thermal management rather than signal routing density or dynamic flex endurance.
The 2 oz RA copper roughly doubles current-carrying capacity per trace width compared to 1 oz grades, reduces DC resistance by approximately half, and meaningfully improves in-plane thermal spreading. The all-polyimide construction eliminates the adhesive thermal bottleneck of conventional flex laminates. Sustained 180ยฐC operation, UL 94V-0 flammability, and IPC-4204/11 certification cover the qualification requirements for automotive, aerospace, industrial, and medical diagnostic applications.
Where AP9232R is the wrong choice: fine-line signal routing, high-cycle dynamic flex zones, cost-sensitive commodity flex circuits, and designs where 2 oz copper stiffness conflicts with the required bend radius. For the growing category of power flex and rigid-flex designs โ EV power distribution, aerospace power harness replacement, industrial VFD flex tails, and LED thermal management boards โ AP9232R delivers a combination of electrical and thermal properties that is difficult to match from any other standard all-polyimide flex laminate in the current product range.
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