Flame Retardant Nylon (PA6 / PA66)

Q: What flame retardant is used in nylon 6 and nylon 66?

Three main routes: halogen-free phosphinate systems (aluminum diethylphosphinate with a nitrogen synergist) for connectors needing high CTI, red phosphorus for the lowest loading in dark parts, and brominated systems with antimony trioxide for cost-driven, halogen-tolerant parts.

Q: Can flame retardant nylon be supplied as masterbatch?

Yes. Rectivas supplies both powder additive packages for compounders and pre-dispersed masterbatch on a PA carrier for molders without in-house compounding, matched to your resin grade and target rating.

Nylon holds connectors, relays and structural parts together under heat and load — but neat PA6/PA66 burns and drips. We supply halogen-free and brominated flame retardant systems built for both resins, as additive powder and masterbatch, reaching UL94 V-0 down to 0.8 mm with the CTI and glow-wire performance connector specs demand.

Request Nylon FR Recommendation Compare the Three Routes

GradesFR-PA6 · FR-PA66

FormsAdditive powder · masterbatch

SystemsHalogen-free · brominated

TargetsUL94 V-0 · GWIT · CTI

Injection molded flame retardant nylon connector parts

Fig. N01 — molded FR-PA66 connector parts

Connector-grade parts molded from flame retardant nylon compound.

FR-PA series
Form — additive / masterbatch
Goal — V-0, high CTI
Use — connectors, relays, E&E

01 / 07Why Nylon Needs Help

Nylon Is Tough. It Is Not Fire-Safe.

PA6 and PA66 are the connector world’s default resin — strong, heat-resistant, dimensionally stable. Neither burns safely on its own. Unfilled nylon can scrape a marginal V-2 because it drips away from the flame; glass-filled nylon loses even that, because the fibers wick the flame instead of letting it drop. Any real UL94 or glow-wire rating needs a formulated package.

Grades: FR-PA6 · FR-PA66 Forms: additive powder · masterbatch Fit: connectors, relays, E&E, automotive

N-01

FR-PA6

Lower processing temperature, generally lower cost. General E&E housings, cable ties and clips where PA66’s extra heat resistance is not required.

Halogen-free or brominated on request
UL94 V-0 in unfilled and glass-filled grades

N-02

FR-PA66

Higher heat deflection and dimensional stability — the connector and relay standard, including automotive and EV applications.

Glow-wire and CTI-oriented packages available
Survives 280–300 °C processing

N-03

Additive or Masterbatch

Powder packages for compounders running their own twin-screw line; pre-dispersed masterbatch on a PA carrier for molders dosing at the press.

Loading and carrier matched to your line
See additives vs masterbatch for the trade-off

02 / 07Systems

Three Flame Retardant Routes for Nylon

Same three chemistries as any engineering plastic — color, electrical spec and halogen policy decide which one fits your part.

System	Typical loading	Strengths	Related page
Halogen-free phosphinate	15–20% + N-synergist	High CTI (400–600V), light colors, V-0 at 0.8mm	DEPAL page
Red phosphorus	6–10%	Lowest loading, best mechanical retention, dark colors only	Phosphorus family
Brominated + antimony trioxide	12–20%	Lowest cost, any color, halogen-tolerant markets only	DBDPE page

In unfilled nylon parts (cable ties, clips), melamine cyanurate alone often reaches V-0 at just 8–12% — the cheapest halogen-free route, but it only works before glass fiber enters the resin. For the full resin-by-resin selection logic, including PA66 vs PA6 processing differences, see our flame retardant nylon 66 selection guide.

03 / 07Applications

Where Flame Retardant Nylon Is Used

Nearly all of it is E&E and automotive — parts where a fire fault has to stop at the part, not spread through it.

CONN

Connectors & Terminal Blocks

CTI and glow-wire performance often matter as much as UL94 — the phosphinate route’s home turf.

RELAY

Relays & Circuit Breakers

Thin-wall housings around live current; V-0 at 0.8mm is now the common ask, not the exception.

AUTO

Automotive & EV Hardware

Under-hood brackets, battery hardware, charging connectors — heat resistance plus fire rating together.

GEN

General E&E Housings

Cable ties, clips, sensor housings — where unfilled PA and a lean melamine cyanurate package keep cost down.

04 / 07Standards

What Connector Specs Actually Ask For

UL94 is rarely the whole exam anymore. Confirm all three before formulating.

01UL94 class at actual wall (0.8–1.6mm)

02Glow wire GWIT / GWFI (IEC 60695)

03CTI / arc tracking resistance

04Halogen-free declaration or RoHS-only

05Color (natural / black / HV orange)

06Glass fiber content

07Moisture / hydrolysis exposure

08Processing temperature window

09Cost per rated part

05 / 07Manufacturing

FR Nylon Supply from Rectivas

FR-PA6 and FR-PA66 are standing grades — halogen-free by default, brominated on request — compounded on our twin-screw line and burn-verified in-house before shipment.

Forms: additive powder · masterbatch Testing: in-house UL94 · LOI ladders Documents: TDS · SDS · COA · CTI (Hebei) reports

C-01System selection: phosphinate, red phosphorus or brominated
C-02Glow-wire and CTI-oriented formulation
C-03Twin-screw loading ladders and burn verification
C-04Moisture / hydrolysis-aware drying and stabilization guidance
C-05Pre-dispersed masterbatch on PA carrier
C-06Batch QC with TDS / SDS / COA per shipment
C-07Export packaging and worldwide delivery

UL94 burn verification of a flame retardant nylon compound

Fig. N02 — burn verification in our labEvery system burn-tested at your actual wall thickness.

Export packaging of flame retardant nylon additives and masterbatch

Fig. N03 — export packagingBags, big bags and palletized supply for overseas buyers.

06 / 07FAQ

Buyer Questions About Flame Retardant Nylon

The four that open most nylon FR inquiries.

What is flame retardant nylon used for?

Connectors, relays, circuit breakers, terminal blocks, sensor housings and structural automotive parts — anywhere PA6 or PA66 needs a UL94 rating alongside its natural toughness and heat resistance.

Is PA6 or PA66 better for flame retardant parts?

Both take the same flame retardant systems. PA66 offers higher heat resistance and dimensional stability — common in automotive and high-temperature connectors. PA6 processes cooler and often costs less, suiting general E&E parts. The resin choice, not the flame retardant, usually decides between them.

What flame retardant is used in nylon 6 and nylon 66?

Three main routes: halogen-free phosphinate (aluminum diethylphosphinate with a nitrogen synergist) for high-CTI connectors, red phosphorus for the lowest loading in dark parts, and brominated systems with antimony trioxide for cost-driven, halogen-tolerant parts.

Can flame retardant nylon be supplied as masterbatch?

Yes — powder additive packages for compounders, or pre-dispersed masterbatch on a PA carrier for molders without in-house compounding, matched to your resin grade and target rating.

Request a Flame Retardant Nylon Recommendation

Send your resin (PA6 or PA66), glass content, wall thickness and the full spec line — UL94 class, glow wire, CTI. We will recommend the system and prove it in our burn lab before you commit a trial.

Send Nylon FR RFQ Email sales@rectivas.com

Include in your inquiryPA-RFQ

ResinPA6 or PA66; glass fiber content
Target ratingUL94 class at actual wall; GWIT/CTI if specified
ColorNatural, black, or HV orange
ComplianceHalogen-free declaration, RoHS, REACH
Trial volumeSample quantity and expected annual demand