DuPont Pyralux LF9130R: Engineer’s Complete Guide to 1 oz Cu / 3 mil PI Acrylic Flex for Rigid-Flex Fabrication

There is a recurring decision in rigid-flex stackup planning that most engineers encounter by the second or third project: how thick does the flex core need to be? LF9110R (1 mil Kapton) is the workhorse, LF9120R (2 mil Kapton) gives you more isolation and better via depth — and DuPont Pyralux LF9130R adds another full mil of polyimide to arrive at a 3 mil (76 µm) Kapton core. That progression is not arbitrary. The LF9130R’s 3 mil Kapton sits at a well-defined design point: the thickest standard LF single-sided construction before the jump to LF9150R (5 mil), and the correct specification when rigid-flex fabrication demands more isolation voltage between layers, more dielectric depth for via barrel integrity in multilayer builds, or a flex core stiff enough to resist in-plane distortion across large rigid-flex panels through multiple lamination press cycles.

This guide documents the complete LF9130R specification, decodes the part number with precision, explains why the 3 mil Kapton exists as a distinct product from LF9110R and LF9120R, positions the construction correctly in the full LF family, and delivers the fabrication and design rules that matter specifically for rigid-flex applications.

Decoding the DuPont Pyralux LF9130R Part Number

DuPont Pyralux copper-clad laminated composites are constructed of DuPont Kapton polyimide film with copper foil on one or both sides, bonded together with a proprietary C-staged modified acrylic adhesive. All copper-clad laminates are available with rolled, annealed copper or electro-deposited copper. For LF9130R, the product code encodes the construction directly:

Code Segment	What It Encodes	LF9130R Value
LF	Acrylic-based laminate family	C-staged modified acrylic adhesive construction
9	Copper weight designator	1 oz/ft² (35 µm) copper
1	Product series designator	LF 1 oz copper series
3	Kapton thickness designator	3 mil (76 µm) Kapton polyimide
0	Layer structure designator	Single-sided clad
R	Copper foil type	Rolled-Annealed (RA) copper

The “3” in the fourth position is what distinguishes LF9130R from LF9110R (1 mil Kapton), LF9120R (2 mil Kapton), and LF9150R (5 mil Kapton) within the same 1 oz / 1 mil adhesive copper series. The “0” in the fifth position confirms single-sided construction — copper on one face only. The “R” suffix confirms rolled-annealed copper, differentiating it from LF9130E (electro-deposited) and LF9130D (double-treated RA) variants.

LF9130R Confirmed Three-Layer Construction

LF9130R is listed in DuPont’s official single-sided copper-clad product table as 1 oz/ft² copper, 1 mil adhesive, and 3 mil Kapton, with IPC certification. The three-layer stack dimensions are:

LF9130R Stack Dimensions

Layer	Material	Thickness
Conductor	1 oz (35 µm) Rolled-Annealed copper	35 µm
Adhesive	C-staged modified acrylic adhesive	25 µm (1 mil)
Dielectric	DuPont Kapton polyimide film	76 µm (3 mil)
Total laminate core		~136 µm

The 136 µm core before coverlay is 51 µm thicker than LF9110R (85 µm) and 25 µm thicker than LF9120R (111 µm). That cumulative dielectric increase — all attributable to the 3 mil Kapton versus 1 mil and 2 mil alternatives — is what drives every performance advantage the LF9130R holds in rigid-flex fabrication over thinner LF constructions.

DuPont Pyralux LF9130R Full Technical Specifications

All electrical and laminate-level properties for the LF9130R are consistent with the Pyralux LF family specification. The performance data reported by DuPont for the LF series represents typical values for a 1 oz copper / 1 mil adhesive / 1 mil Kapton construction — the dielectric properties of the acrylic adhesive and Kapton layers are the same at all Kapton thicknesses within the LF series.

Electrical Properties

Property	Value	Frequency	Test Method
Dielectric Constant (Dk)	3.6	1 MHz	IPC-TM-650 2.5.5.3
Dielectric Constant (Dk)	3.0	10 GHz	ASTM D2520
Loss Tangent (Df)	0.02	1 MHz	IPC-TM-650 2.5.5.3
Loss Tangent (Df)	0.02	10 GHz	ASTM D2520
Theoretical Isolation (3 mil Kapton)	~15,200 V	—	Calculated (200 V/µm × 76 µm)
Volume Resistivity	>10¹⁵ Ω·cm	—	IPC-TM-650 2.5.17
Surface Resistance	>10¹⁴ Ω	—	IPC-TM-650 2.5.17

Mechanical and Adhesion Properties

Property	Value	Test Method
Peel Strength (after lamination)	1.8 N/mm (10 lb/in)	IPC-TM-650 2.4.9
Peel Strength (after solder)	1.6 N/mm (9 lb/in)	IPC-TM-650 2.4.9
Dimensional Stability (MD/TD)	±0.10%	IPC-TM-650 2.2.4
Solder Float (288°C, 10 s)	Pass	IPC-TM-650 2.4.13

Lamination Process Conditions

Parameter	Value
Part Temperature	182–199°C (360–390°F)
Pressure	14–28 kg/cm² (200–400 psi)
Time	1–2 hours at temperature

Compliance and Certifications

Standard	Status
IPC-4204/1	Certified
RoHS	Compliant
ISO 9001:2015	Manufactured under certified QMS
Certificate of Conformance	Available with every batch

Why 3 mil Kapton Is the Right Core for Rigid-Flex Fabrication

Stepping from LF9120R to LF9130R is not something engineers do for marginal gains. There are specific rigid-flex fabrication scenarios where a 3 mil Kapton flex core is the appropriate — and sometimes the only adequate — specification, and understanding them is the engineering substance behind choosing LF9130R.

Interlayer Isolation in Mixed-Voltage Rigid-Flex Stackups

Pyralux LF laminated composites are typically used to produce high reliability, high density circuitry of flexible, rigid-flex, and all-flexible multilayer constructions. In a multilayer rigid-flex board where flex core layers carry signals at different voltage potentials — power rails adjacent to logic signal layers, or high-voltage drive lines crossing low-voltage sensor signal planes — the 3 mil (76 µm) Kapton in LF9130R delivers approximately 50% more theoretical isolation voltage than the 2 mil (51 µm) Kapton in LF9120R, and three times the isolation of LF9110R’s 1 mil core. With Kapton’s 200 V/µm dielectric strength, the 3 mil core provides approximately 15,200 V theoretical breakdown across the polyimide layer alone — well above the practical working voltage requirements of industrial, automotive, and medical rigid-flex power distribution designs.

Via Barrel Depth and Mechanical Reliability in Multilayer Builds

In a multilayer rigid-flex construction with several bonded flex core layers, via barrels must penetrate through the entire stack including coverlay, bondply, and the flex core dielectrics. The depth of via barrel that runs through each individual flex layer is a direct function of the Kapton thickness in that layer. A via running through an LF9130R core has 76 µm of polyimide dielectric to grip — compared to 51 µm (LF9120R) or 25 µm (LF9110R). That additional dielectric depth around the via barrel reduces the risk of pad-to-barrel separation during thermal cycling, particularly in multilayer rigid-flex assemblies that undergo aggressive temperature cycling from −40°C to +125°C or above. Every additional micron of Kapton around the via barrel is mechanical anchorage that resists the Z-axis expansion stress that drives barrel cracking in high-reliability applications.

Panel Dimensional Stability Through Multiple Lamination Cycles

DuPont Pyralux LF products have been the industry standard in high reliability applications for over 35 years, with the ability to withstand multiple lamination cycles without degradation. Rigid-flex fabrication typically involves three to five press lamination cycles — rigid cap layer bonding, coverlay lamination, stiffener attachment, and final assembly lamination. Each press cycle subjects the flex core to elevated temperature and pressure. The 136 µm core of LF9130R is 60% stiffer in bending than LF9110R’s 85 µm core (bending stiffness scales with thickness cubed), which means it resists in-plane warping and dimensional drift more effectively through repeated lamination cycles. This matters for registration accuracy in multilayer rigid-flex panels, where trace and via registration errors accumulate across lamination cycles if the flex core lacks adequate stiffness to hold its in-plane geometry.

Controlled Impedance on Flex Layers With Wider Trace Windows

At 3 mil (76 µm) Kapton plus 1 mil (25 µm) acrylic (combined ~101 µm effective dielectric), a 50Ω microstrip trace on LF9130R at 1 oz copper falls at approximately 7–9 mil trace width — comfortably above the reliable etching minimum for 35 µm copper at most qualified flex fabricators. Pushing the same impedance target on LF9110R’s thinner combined dielectric produces a 3–5 mil trace requirement, approaching the fabrication limit with proportionally higher impedance variation from etch scatter. For rigid-flex designs that combine moderate signal density with controlled impedance on the flex layers, LF9130R’s thicker core is a genuine yield advantage.

LF9130R in the Full Pyralux LF Family

Standard LF Single-Sided Clad — 1 oz Series Comparison

The standard DuPont Pyralux single-sided 1 oz copper constructions include LF9110R (1 mil adhesive, 1 mil Kapton), LF9120R (1 mil adhesive, 2 mil Kapton), LF9130R (1 mil adhesive, 3 mil Kapton), and LF9150R (1 mil adhesive, 5 mil Kapton), all with IPC certification.

Product Code	Cu (oz / µm)	Adhesive (mil / µm)	Kapton (mil / µm)	Core	Best Fit
LF9110R	1 oz / 35 µm	1 mil / 25 µm	1 mil / 25 µm	~85 µm	Standard FPC, low-cost flex
LF9120R	1 oz / 35 µm	1 mil / 25 µm	2 mil / 51 µm	~111 µm	HDI flex, moderate isolation
LF9130R	1 oz / 35 µm	1 mil / 25 µm	3 mil / 76 µm	~136 µm	Rigid-flex core, mixed voltage
LF9150R	1 oz / 35 µm	1 mil / 25 µm	5 mil / 127 µm	~197 µm	High-isolation, stiff flex layers

LF9130R vs. LF9110R vs. LF9120R: The 3 mil Advantage Quantified

Parameter	LF9110R	LF9120R	LF9130R
Kapton thickness	1 mil / 25 µm	2 mil / 51 µm	3 mil / 76 µm
Total core	~85 µm	~111 µm	~136 µm
Theoretical isolation (PI only)	~5,000 V	~10,200 V	~15,200 V
50Ω microstrip trace width	~3.5–5 mil	~5–7 mil	~7–9 mil
Via barrel depth (Kapton)	25 µm	51 µm	76 µm
Lamination cycle stability	Baseline	Better	Best in LF 1oz series
Panel handleability	Standard	Better	Best in LF 1oz series
Static bend radius (6× total fin.)	~0.8 mm	~1.0 mm	~1.1 mm
Dk @ 1 MHz	3.6	3.6	3.6
Df @ 1 MHz	0.02	0.02	0.02
IPC-4204/1	Certified	Certified	Certified

The data tells the story cleanly. LF9130R does not change any dielectric or adhesion specification — it advances via reliability, isolation margin, impedance headroom, and dimensional stability to the best levels achievable in the 1 oz LF single-sided series. These improvements come at the cost of a slightly larger minimum static bend radius (approximately 1.1 mm vs. 0.8 mm at LF9110R) and marginally higher material cost from the additional Kapton content.

Real-World Applications for DuPont Pyralux LF9130R

The LF9130R occupies a specific and coherent application niche within rigid-flex fabrication. Its thickest-standard 1 oz LF core positions it across several demanding design classes.

Multilayer Rigid-Flex for Industrial Power Electronics

Industrial servo drives, inverter control boards, and motor controller rigid-flex assemblies combine power distribution traces carrying 24 V–600 V DC bus signals with low-voltage logic and sensor signals in the same multilayer construction. The LF9130R’s 3 mil Kapton provides the interlayer isolation margin that separates power and signal layers without resorting to the adhesiveless AP series, which carries a cost premium over the LF construction. For designs where signal frequencies stay below 500 MHz and operating temperature stays below the acrylic adhesive’s effective working range, LF9130R delivers the required isolation at commercial materials cost.

Aerospace and Defense Rigid-Flex Signal Distribution

DuPont Pyralux LF products have low outgassing with NASA data available, making them appropriate for aerospace applications where outgassing in sealed or semi-sealed enclosures is a qualification requirement. Avionics rigid-flex assemblies routing mixed-voltage signals — 28 V aircraft power, 5 V logic, 3.3 V serial bus signals — benefit from LF9130R’s isolation margin on the flex core layers while the IPC-4204/1 certification satisfies the materials qualification documentation requirements of AS9100 supply chains.

Automotive Rigid-Flex for Mixed-Signal Under-Hood Electronics

Engine control modules, transmission control units, and advanced driver assistance system (ADAS) sensor fusion boards increasingly use multilayer rigid-flex construction. Operating temperatures up to +125°C in under-hood environments are within the Kapton polyimide’s working range (Kapton film itself is stable well above 200°C), though designers should verify that the acrylic adhesive’s cured Tg (~100–130°C) is not the thermal ceiling for their specific application. For interior ADAS applications where peak temperatures stay below 120°C, LF9130R’s three-layer construction is appropriate and commercially competitive.

Medical Device Flex Interconnects With Isolation Requirements

External medical monitoring devices — ECG systems, infusion pump electronics, patient monitoring assemblies — that isolate patient-connected circuits from mains-referenced electronics require flex or rigid-flex interconnects with meaningful interlayer isolation voltage. The LF9130R’s 3 mil Kapton (approximately 15,200 V theoretical Kapton-only isolation) provides significant working voltage margin for designs requiring IEC 60601-1 creepage and clearance compliance on flex layers, after applying appropriate safety factor reductions from theoretical breakdown values. DuPont’s standard caution applies: Pyralux LF is not approved for permanent human implantation.

High-Reliability Industrial Sensor Rigid-Flex

Pressure transducer electronics, flow meter signal conditioning boards, and temperature sensing rigid-flex assemblies in process industry applications benefit from LF9130R’s combination of multi-lamination cycle stability, 3 mil Kapton isolation, and IPC-4204/1 certification. These designs typically operate within temperature ranges that the acrylic adhesive system handles reliably, at signal frequencies well below 500 MHz, making the cost-competitive LF9130R a better specification than the AP adhesiveless series for the vast majority of industrial sensor applications.

Fabrication and Design Rules for LF9130R Rigid-Flex Applications

Bend Radius Calculation for LF9130R

Total finished circuit thickness for LF9130R with a standard 50 µm film polyimide coverlay on the copper face:

Layer	Thickness
Coverlay (PI film + acrylic adhesive)	~50 µm
Copper (1 oz RA)	35 µm
Acrylic adhesive	25 µm
Kapton polyimide	76 µm
Total finished thickness	~186 µm

Applying IPC-2223 bend radius multipliers to the 186 µm finished thickness:

Flex Type	IPC-2223 Multiplier	LF9130R Min. Bend Radius
Static — bend-to-install (once)	6× total thickness	~1.1 mm
Dynamic — repeated flex cycles	10× total thickness	~1.9 mm
High-cycle dynamic (>10,000 cycles)	15× total thickness	~2.8 mm

At 186 µm finished thickness, LF9130R’s minimum static bend radius of approximately 1.1 mm is only marginally larger than LF9120R’s 1.0 mm — a difference that is within design tolerance for most rigid-flex bend zone geometries. The thicker Kapton does not significantly constrain the flex zone design in typical rigid-flex assemblies.

Bend Zone Orientation for Single-Sided Construction

LF9130R is a single-sided construction with copper on one face. Always orient the flex circuit in the bend zone so that the copper layer is on the outside (tension side) of the bend rather than the inside (compression side). The outer-bend orientation reduces peak strain at the copper-to-adhesive interface and extends flex fatigue life — this is a consistent recommendation for all single-sided flex constructions under IPC-2223.

Current Capacity at 1 oz RA Copper

Current capacity on LF9130R is identical to other 1 oz LF constructions — the Kapton thickness has no influence on copper current capacity.

Trace Width	Max Continuous Current (External, 1 oz, 20°C rise)
0.5 mm (20 mil)	~1.1 A
1.0 mm (39 mil)	~1.8 A
2.0 mm (79 mil)	~2.8 A
3.0 mm (118 mil)	~3.7 A
5.0 mm (197 mil)	~5.2 A

Controlled Impedance Reference for LF9130R

For 1 oz (35 µm) RA copper on LF9130R’s combined dielectric (1 mil acrylic + 3 mil Kapton, effective Dk approximately 3.5–3.6):

Impedance Target	Configuration	Approx. Trace Width
50Ω single-ended	Microstrip	7–9 mil (178–229 µm)
75Ω single-ended	Microstrip	4.5–6 mil (114–152 µm)
100Ω differential	Edge-coupled microstrip	4–5 mil trace / 6–8 mil space

These values represent the widest, most production-tolerant trace geometries in the 1 oz LF single-sided series — a direct consequence of the 3 mil Kapton’s thicker combined dielectric. Always validate against your fabricator’s characterisation data for acrylic LF at your specific stackup.

Via Design in LF9130R Multilayer Rigid-Flex Construction

When LF9130R is used as a flex core layer in a multilayer rigid-flex build, apply these via guidelines for the LF9130R layers specifically:

Via Feature	LF9130R Guideline
Min. drill diameter (PTH, mechanical)	0.15 mm (150 µm)
Min. drill diameter (laser micro-via)	0.10 mm (100 µm)
Min. annular ring (IPC-6013 Class 2)	0.075 mm (75 µm)
Drill-to-copper clearance	0.10 mm (100 µm) minimum
Via placement in flex bend zone	Avoid — place in rigid sections
Via-to-edge clearance (flex zone edge)	≥0.15 mm from flex zone boundary

The last two rules apply across all LF constructions in rigid-flex: placing vias in the flex bend zone creates stress concentration at the barrel-to-laminate interface under thermal cycling and flex cycling. All vias should be located in the rigid sections of the board or at controlled-depth transitions.

Multi-Lamination Cycle Guidance

Pyralux LF is able to withstand multiple lamination cycles without degradation. For rigid-flex constructions using LF9130R as a flex core layer through three to five press cycles, follow DuPont’s standard LF lamination conditions (182–199°C, 14–28 kg/cm², 1–2 hours) for each cycle. Because B-staged adhesive contains trace quantities of unreacted monomers, adequate ventilation is recommended during lamination. This applies to the bondply and coverlay materials used alongside LF9130R — the LF9130R itself is fully C-staged (cured) as supplied and does not contribute to monomer outgassing during press cycles.

Pre-Assembly Moisture Bake-Out

As with all Pyralux LF constructions, bake LF9130R assemblies at 120°C for a minimum of 4 hours before reflow soldering and process within 8 hours of bake completion. The 76 µm Kapton film in LF9130R holds proportionally more absorbed moisture than the 25 µm or 51 µm films in LF9110R and LF9120R — making this pre-bake step correspondingly more important for LF9130R assemblies stored in humid conditions outside original packaging.

Storage Requirements

Pyralux LF Copper-Clad Laminate should be stored in original packaging at temperatures below ambient, controlled humidity. DuPont specifies storage at 4–29°C (40–85°F) and below 70% relative humidity, not frozen, kept dry and well-protected. A two-year warranty applies from the date of shipment. Certificate of Conformance is provided with every batch.

LF9130R vs. Competing Rigid-Flex Core Laminates

Parameter	LF9130R (DuPont)	LF9120R (DuPont)	AP9131R (DuPont)	Generic Acrylic 1oz/3mil PI
Cu weight	1 oz / 35 µm RA	1 oz / 35 µm RA	1 oz / 35 µm RA	1 oz / 35 µm
Adhesive	1 mil / 25 µm acrylic	1 mil / 25 µm acrylic	None (adhesiveless)	~1 mil acrylic
Dielectric	3 mil / 76 µm Kapton	2 mil / 51 µm Kapton	3 mil / 75 µm PI	~3 mil PI
Total core	~136 µm	~111 µm	~145 µm	~135 µm
Dk @ 1 MHz	3.6	3.6	3.4	~3.5–3.8
Df @ 1 MHz	0.02	0.02	0.002	~0.02–0.04
Isolation (PI @ 200V/µm)	~15,200 V	~10,200 V	~15,000 V	Variable
Adhesive Tg	~100–130°C	~100–130°C	N/A	~80–120°C
IPC-4204/1	Certified	Certified	N/A (IPC-4204/11)	Varies
ISO 9001:2015	Full DuPont	Full DuPont	Full DuPont	Factory-dependent
Relative cost	Moderate	Lower	Higher	Lowest

The comparison against AP9131R — the adhesiveless equivalent at the same 3 mil polyimide core — is the decision that matters most for rigid-flex designers. AP9131R delivers 10× lower Df, 20°C higher effective Tg from the adhesiveless construction, and IPC-4204/11 certification for programs requiring the adhesiveless standard. For rigid-flex designs carrying signals above 500 MHz, operating continuously above 130°C, or requiring IPC-4204/11 certification, AP9131R is the correct specification. For the large majority of industrial, automotive, and commercial rigid-flex designs below these thresholds, LF9130R delivers equivalent Kapton isolation, adequate interlayer voltage margin, and multi-lamination cycle durability at a commercially competitive materials cost.

Sourcing DuPont Pyralux LF9130R

DuPont Pyralux LF products are supplied in sheet form with no refrigeration required for storage, have low outgassing with NASA data available, and carry a two-year product performance warranty. Standard sheet dimensions are 24×36 in (610×914 mm), 24×18 in (610×457 mm), and 12×18 in (305×457 mm), with four to twenty-five sheets per pack. LF9130R is a standard IPC-certified construction with typical distributor lead times of 2–4 weeks for standard quantities.

When writing engineering documentation, specify LF9130R by full DuPont product code on all BOM and fabrication drawings: “DuPont Pyralux LF9130R, 1 oz RA copper / 1 mil acrylic / 3 mil Kapton, single-sided, IPC-4204/1 certified.” This prevents unauthorised substitution of LF9110R or LF9120R — which share identical Certificate of Conformance electrical properties and are distinguished only by the Kapton thickness field.

DuPont PCB materials cover the complete Pyralux product architecture — LF, AP, FR, and specialty constructions. For rigid-flex programs requiring supply chain depth across both the acrylic LF series and adhesiveless AP series, understanding the full DuPont Pyralux family enables procurement teams to make cost-optimised, performance-appropriate specifications at every tier of a product portfolio.

Useful Resources for Rigid-Flex Designers Using LF9130R

Resource	Description	URL
DuPont Pyralux LF Official Datasheet (PDF)	Full TDS confirming LF9130R construction and specs	https://insulectro.com/wp-content/uploads/2021/09/EI-10117-Pyralux-LF-CCL-Data-Sheet.pdf
DuPont Pyralux LF — Elco PCB (PDF)	Complete LF datasheet with full product table	https://www.elcopcb.com/wp-content/uploads/2024/04/PyraluxLFclad_DataSheet.pdf
DuPont Pyralux LF Official Product Page	Full LF family overview including coverlays and bondplys	https://www.dupont.com/electronics-industrial/pyralux-lf.html
DuPont Pyralux Product Selector	Product code identification for custom LF constructions	https://pyralux.dupont.com
DuPont Pyralux AP Datasheet (for comparison)	AP adhesiveless specs for LF vs. AP evaluation	https://insulectro.com/wp-content/uploads/2021/09/EI-10124-Pyralux-AP-Data-Sheet.pdf
DuPont Pyralux LF Coverlay Datasheet	Coverlay and bondply constructions compatible with LF9130R	https://www.cirexx.com/wp-content/uploads/PyraluxLFcoverlay_DataSheet.pdf
IPC-4204/1 Specification	Qualification standard for acrylic adhesive flex laminates	https://www.ipc.org
IPC-2223 Flexible PCB Design Standard	Bend radius and DFM guidelines for flex and rigid-flex	https://www.ipc.org
IPC-6013 Flex PCB Performance Standard	Qualification and acceptance testing, via reliability criteria	https://www.ipc.org
IPC-TM-650 Test Method Database	All test methods referenced in LF9130R datasheet	https://www.ipc.org/TM

Frequently Asked Questions About DuPont Pyralux LF9130R

1. What is the confirmed construction of LF9130R and how does it differ from LF9110R and LF9120R?

DuPont Pyralux LF9130R is confirmed in DuPont’s official single-sided product table as: 1 oz/ft² (35 µm) rolled-annealed copper / 1 mil (25 µm) C-staged modified acrylic adhesive / 3 mil (76 µm) DuPont Kapton polyimide film, single-sided, IPC-4204/1 certified. Total laminate core before coverlay is approximately 136 µm. Compared to LF9110R (85 µm core, 1 mil Kapton), the LF9130R has 51 µm more total thickness, triple the Kapton dielectric depth for via barrels, three times the theoretical Kapton-only isolation voltage (~15,200 V vs. ~5,000 V), and a 50Ω microstrip trace width in the 7–9 mil range vs. 3.5–5 mil range. Compared to LF9120R (111 µm core, 2 mil Kapton), LF9130R adds 25 µm of additional Kapton, improving isolation voltage by approximately 5,000 V and shifting 50Ω trace widths from 5–7 mil to 7–9 mil. All dielectric properties (Dk, Df), peel strength, dimensional stability, and certifications are identical across all three constructions.

2. Is LF9130R suitable for use as a flex core layer in multilayer rigid-flex construction?

Yes — this is the primary application the LF9130R is designed to serve. The 3 mil Kapton core provides the interlayer isolation, via barrel depth, and multi-lamination cycle dimensional stability that single-layer flex positions in multilayer rigid-flex stackups require. When specifying LF9130R in a rigid-flex build, pair it with compatible Pyralux LF coverlay and bondply materials for the flex zone, and follow DuPont’s standard lamination conditions (182–199°C, 14–28 kg/cm², 1–2 hours) for each press cycle. The LF9130R is rated to withstand multiple lamination cycles without degradation — a confirmed advantage over adhesiveless AP constructions, which DuPont specifies for the same application but at higher cost.

3. Why would an engineer choose LF9130R over AP9131R for a rigid-flex design?

The choice reduces to signal frequency, temperature, certification requirements, and cost. AP9131R (adhesiveless, Df 0.002) is correct when the design carries signals above 500 MHz–1 GHz (where LF9130R’s acrylic-system Df of 0.02 becomes a meaningful contributor to insertion loss), when continuous operating temperature exceeds approximately 130°C (where the acrylic adhesive Tg limits LF9130R’s reliable service), or when the program requires IPC-4204/11 certification (the adhesiveless laminate standard, required by some aerospace and medical OEMs). Choose LF9130R when the design operates below 500 MHz, temperature stays below 130°C continuously, and IPC-4204/1 certification is sufficient — which covers the majority of industrial, automotive interior, and commercial electronics rigid-flex programs. The materials cost difference between LF9130R and AP9131R is significant at production volumes.

4. What is the maximum continuous operating temperature for LF9130R in a rigid-flex assembly?

The LF9130R’s effective maximum continuous service temperature is approximately 100–130°C, governed by the cured acrylic adhesive’s glass transition temperature rather than the Kapton film (which is stable well above 200°C). Brief elevated temperature exposure — such as lead-free reflow at 260°C peak — is tolerated because the solder float test at 288°C for 10 seconds is passed. However, sustained operation at or above the adhesive Tg will cause the acrylic bondline to soften and lose its dimensional stability and peel strength over time. For applications requiring continuous operation above 130°C, the adhesiveless Pyralux AP series (Tg 220°C, no adhesive degradation mechanism) is the appropriate specification.

5. Is LF9130R available in an electro-deposited (ED) copper variant for fine-pitch designs?

Yes. LF9130E (electro-deposited copper, 3 mil Kapton) and LF9130D (double-treated RA copper, 3 mil Kapton) are available as variants of the same construction. For rigid-flex designs that combine the isolation and dimensional stability advantages of the 3 mil Kapton core with fine-pitch signal traces below 3 mil (75 µm) — where ED copper’s columnar grain structure provides more consistent etch sidewall geometry — LF9130E is the appropriate specification. The trade-off is that LF9130E should be limited to static flex applications; the columnar grain structure of ED copper is more susceptible to fatigue cracking under repeated bending than the RA copper in LF9130R. For designs combining 3 mil Kapton with any dynamic flex requirement, LF9130R (RA copper) is the correct specification.

Summary

DuPont Pyralux LF9130R — 1 oz (35 µm) rolled-annealed copper / 1 mil (25 µm) acrylic adhesive / 3 mil (76 µm) Kapton polyimide, single-sided, IPC-4204/1 certified — sits at the thickest practical standard single-sided LF core for rigid-flex fabrication before entering the 5 mil Kapton territory of LF9150R. Its 136 µm core delivers the via barrel depth, interlayer isolation margin (~15,200 V theoretical), controlled impedance trace width headroom (7–9 mil at 50Ω), and multi-lamination cycle dimensional stability that the LF9110R and LF9120R constructions cannot fully provide in demanding multilayer rigid-flex builds. For industrial, automotive, aerospace, and medical rigid-flex programs operating below 500 MHz and 130°C continuous, where IPC-4204/1 certification satisfies program requirements, LF9130R is the cost-effective, thoroughly characterised, and universally available specification for the flex core layers of the construction.