Skip to content
NetProto

Flame Retardant Additives

Flame Retardant Additives: How They Change Resin and Process

Buyers often add FR to a BOM without updating cosmetic or dimensional assumptions from the unfilled grade.

Get Instant QuoteArticles

Flame Retardant Additives

FR packages change more than a label

Flame retardant additives alter flow, shrink, and surface more than unfilled grades.

Buyers often add FR to a BOM without updating cosmetic or dimensional assumptions from the unfilled grade.

Additive FR can reduce flow, increase weld line visibility, and shift shrink versus the same base without FR.

Matching gray PC/ABS electronics housings, one standard and one FR grade, on studio gray.

UL 94 ratings belong to specific supplier grades and thickness; they are not automatic when you write FR on a PO.

When to specify it

FR additive checklist

Use this on RFQs and BOMs before you lock a filled grade.

  • Write FR as a filter (for example UL94 V-0 target) plus supplier grade when known.

  • Note wall thickness tied to any listing you cite from supplier docs.

  • Flag high-gloss cosmetic zones separately.

  • Ask for yellow card or supplier letter when the program requires proof.

Trade-offs

Additive FR vs inherently FR resin

Qualitative matrix. Confirm numbers on the supplier datasheet.

RouteProcess feelBuyer note
Additive FR in ABS/PCCan reduce flowCosmetic weld lines need review
Inherent FR (PPS etc.)Different baseline shrinkStill verify supplier listing
Unfilled same baseEasiest fillNo flame guarantee

Routing

Cosmetic housing FR

Electronics shells often use FR PC/ABS.

Unfilled PC/ABS

  • Easier gloss
  • Lower cost resin
  • No flame filter

FR PC/ABS

  • Flame filter on BOM
  • Weld line planning
  • Verify supplier data

RFQ

What to write on the purchase order

Clear resin callouts reduce quote iterations and T1 surprises.

  1. 1

    State flame filter

    Use V-0 or HB as requirement, not as molder claim.

  2. 2

    Pick base family

    PC/ABS, PBT, or PA FR routes differ.

  3. 3

    Align SPI finish

    Texture can hide or show FR streaks.

  4. 4

    Link UL explainer

    Use the UL 94 ratings article for verification steps.

FAQ

FAQ

Does FR on the PO mean UL pass?

No. Listings attach to grades and thickness from the supplier.

Halogen-free FR?

Category education only; specify the commercial grade from the TDS.

FR and warp?

Filled FR grades can warp more; plan T1 on flat panels.

Related guides

Materials, comparisons, and risks

Internal links only render in cards and CTA blocks.

Next step

Get a quote with your resin specified

Upload CAD and list fill level, color, and flame filter on the instant quote platform.

Upload CAD for an instant quoteGet Instant Quote
Flame Retardant Additives: How They Change Resin and Process | NetProto