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Buyer guide

Flame retardant polypropylene: V-2, V-0 and 5VA grades, halogen-free FR PP and glow wire

We source FR polypropylene for appliance, electrical, automotive and building parts: V-2 and V-0 grades, halogenated and halogen-free, unfilled, talc-filled and glass-filled, from one gaylord (about 1,000 to 1,600 lb) to a truckload. Send the grade you run, or the UL 94 rating, thickness, color and glow-wire values you need, and a polymer chemist reviews it and quotes a match or a qualified equivalent.

Updated October 2026

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The short answer

Standard polypropylene burns and rates HB at best. A small dose of flame retardant gets PP to UL 94 V-2, which allows flaming drips. V-0 needs far more: a brominated flame retardant with antimony trioxide, or a halogen-free intumescent phosphorus system, often around 20–30% or more. 5VA in PP often takes a talc- or glass-filled FR grade at a thicker wall, about 1.8–3 mm in one producer’s family. Every rating belongs to the exact grade at a stated thickness and color, so check the UL yellow card before you substitute.

V-2, V-0 and 5VA polypropylene, and what drives each

Polypropylene is pure hydrocarbon, so it burns readily and drips as it melts. Flame retardants work in three main ways in PP: halogens interrupt the flame chemistry, intumescent phosphorus systems swell into an insulating char, and mineral hydrates release water. Which one a grade uses decides its rating, density, toughness, processing window and compliance documents.

Target	Usual FR system	What it does to the grade	Watch out for
V-2	A low dose of a brominated FR, often with antimony trioxide; or a halogen-free system at low loading	Close to standard PP. One halogen-free unfilled V-2 copolymer lists a density of 0.91 g/cm³, the same as natural PP. The flaming drips carry heat away, which is how V-2 passes.	V-2 allows drips that ignite the cotton. It will not meet a V-0 or glow-wire callout unless the grade lists those values.
V-0, halogenated	Brominated FR with antimony trioxide, often with talc	Much heavier and stiffer. One family’s 20% talc V-0 grades, coded as halogenated, list densities of about 1.39–1.5 g/cm³. Bloom and lower impact are common trade-offs.	Corrosive gases if overheated, antimony trioxide on Prop 65 statements, and customers who require halogen-free.
V-0, halogen-free (intumescent)	Ammonium polyphosphate or other phosphorus and nitrogen systems that swell into char; published work puts V-0 in PP at about 30% loading for some systems	Lower density than the halogenated route at the same rating, good CTI, and no halogen. Often stiffer and more brittle than standard PP.	A narrow processing window, moisture pickup, and mold deposits. Some lose rating if overheated.
V-0, mineral (MDH)	Magnesium hydroxide at very high loading	Rare in molded PP: the filler level needed makes parts heavy and brittle. More common in wire and cable compounds.	Low flow and poor impact. Check the grade sheet carefully.
5VA or 5VB	A V-0 system with talc or glass that helps the char hold together	One producer lists 5VA at 1.8 mm and 2.0 mm on its 20% talc V-0 grades, 5VB at 2.0 mm on a 35% mineral grade, and 5VA at 3.0 mm on a 25% glass halogen-free grade.	5V ratings are listed at thicker walls than the V rating. 5VB allows a hole through the plaque; 5VA does not.

Examples are from one producer’s published FR PP family and from published research, given to show the pattern, not as values for your grade. Read the yellow card and data sheet for the exact grade.

Thickness and color decide what the listing covers

A UL 94 rating is listed by thickness and color, and FR PP shows why. In one producer’s family, a halogen-free 25% glass-filled homopolymer lists V-0 at 1.5 mm but 5VA only at 3.0 mm, and two 20% talc grades list V-0 at 1.5 mm (homopolymer) and 0.75 mm (copolymer). If your thinnest wall is 1.0 mm, a grade listed V-0 only at 1.5 mm is not a V-0 grade for your part.

Color matters too. Pigments, especially carbon black and some organic colors, change how a part burns and chars. A listing may cover all colors, natural and black only, or named color codes. Halogenated FR PP often uses antimony trioxide, which makes bright colors harder; one producer markets grades for building products as free of antimony trioxide for brilliant colors. Check the color line on the card before you add your own concentrate. See UL 94 ratings explained and choosing an FR resin.

Glow wire, RTI and CTI for FR PP

Glow wire. Appliance standards test with a heated wire, not a flame. Under IEC 60335-1, and UL 60335-1 where it applies, insulating parts that support connections carrying more than 0.2 A in unattended appliances typically need a material GWFI of at least 850°C / 1,562°F and a GWIT of at least 775°C / 1,427°F at the part’s thickness, or a glow-wire test on the finished part. FR PP grades vary: in one producer’s family, GWIT runs from 750°C to 850°C / 1,382°F to 1,562°F, so some of its V-0 grades fall short of 775°C / 1,427°F. GWFI and GWIT are tested by IEC 60695-2-12 and IEC 60695-2-13.
V-0 does not mean glow-wire pass. The tests are different. A V-0 FR PP can miss GWIT, and a V-2 grade can carry a high GWFI. Ask for both values at your thickness. See appliance resins.
RTI (UL 746B). The long-term temperature rating. In one producer’s FR PP family, seven of eight grades list an RTI of 65°C / 149°F; one 20% talc V-0 homopolymer lists 105°C / 221°F. RTI, not HDT, sets how hot the part can run for years, so check it on the yellow card. See HDT vs. continuous use temperature.
CTI. Polypropylene resists surface tracking well, and many FR PP grades list a CTI of 600 V (PLC 0, the top category); every grade in one producer’s family does. That is one reason FR PP is used for terminal covers and housings near live parts. Confirm on the card, since some additives and colors lower it.

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Talc-filled and glass-filled FR PP

Talc-filled FR PP. Talc adds stiffness, heat resistance and flatness, and it can help the char hold together, which is why talc appears in many 5V-rated PP grades. It also adds weight. Ask for ash content on the COA so you know the filler level is right. See talc-filled polypropylene.
Glass-filled FR PP. Glass gives strength and creep resistance for brackets, battery supports and housings. Glass fibers can act as a wick and make V-0 harder to reach at thin walls, and in one producer’s family every glass-filled grade lists V-0 at 1.5 mm. Glass-filled PP also warps more because it shrinks differently along and across flow. See glass vs. mineral filled.
Density changes part cost. FR PP is sold by the pound and parts are sold by the piece. In one producer’s family, densities run from 0.91 g/cm³ for an unfilled V-2 grade to about 1.5 g/cm³ for a talc-filled halogenated V-0 grade, so the same part can weigh more than half again as much. Compare cost per part, not per pound.
Copper contact and UV. Parts that touch copper may need a copper-stabilized grade, and outdoor parts need a UV-stabilized grade. Producers flag both in the grade name or on the sheet, so ask.

Processing limits and regrind

Melt temperature. FR additives break down at temperatures standard PP shrugs off. Our processing chart gives 190–274°C / 374–525°F for PP homopolymer, but FR grade sheets often set a lower ceiling, especially for halogen-free intumescent grades. Use the grade sheet’s ceiling, not the PP family range.
Residence time. Keep the shot at a sensible share of barrel capacity, avoid long hot holds, and purge if the press sits idle. Overheated halogenated grades can release corrosive acid gas, and overheated intumescent grades can foam, discolor, lose rating and leave deposits in the mold. Ventilate the press area.
Drying. Natural PP needs no drying, but our drying chart notes that filled and reinforced PP grades are moisture-sensitive (75°C / 167°F for 2 hours when required). Some halogen-free FR grades ask for drying every time, so follow the grade sheet.
Corrosion and wear. Halogenated FR grades can corrode steel if overheated, and talc and glass wear screws and gates. Corrosion-resistant screw and tool steel help on long runs.
Regrind. For UL-recognized parts, UL 746D generally allows up to 25% in-house regrind of the same grade. Each pass also uses up FR and stabilizer, so keep regrind clean, same-grade and steady. See regrind limits by resin.

RoHS, REACH and what halogen-free means

RoHS. Under RoHS (2011/65/EU as amended by 2015/863), PBB and PBDE flame retardants, including decaBDE, are limited to 0.1% by weight in each homogeneous material. Current halogenated FR PP grades use other brominated flame retardants, and producers state RoHS compliance by grade.
REACH and what is coming. DBDPE, a common replacement for decaBDE, was added to the REACH Candidate List of substances of very high concern in November 2025. ECHA has also named aromatic brominated flame retardants, DBDPE among them, as candidates for an EU-wide restriction, and that work is under way. If you sell into the EU, ask which FR the grade uses and for the supplier’s SVHC statement.
Prop 65. Antimony trioxide is on the California Prop 65 list, so it appears on resin statements for many halogenated FR grades. Whether the finished product needs a warning depends on exposure, which is the product maker’s call.
Halogen-free definitions differ. Many electronics customers borrow IEC 61249-2-21, written for circuit board laminates: no more than 900 ppm chlorine, 900 ppm bromine and 1,500 ppm of the two combined. It does not count fluorine. UL 746H, UL’s outline for non-halogenated plastics and color concentrates, draws on that circuit-board approach. UL 2885, UL’s outline for wire and cable materials, uses the halogen-free limits in IEC 60754-3, which also count fluorine and iodine (reported as 1,000 ppm each). So a grade with a PTFE anti-drip agent can pass one definition and fail another. Ask for the customer’s written definition.
PFAS. Many V-0 grades use a little PTFE as an anti-drip agent. Ask for a PFAS statement if your customer needs one. See PFAS-free alternatives and compliance documents.

Where FR PP is used, and which test applies

Part	Usual FR PP	Test that often decides it
Appliance housings, dishwasher and washer parts, cooker hoods, coffee maker bases	V-2 or V-0, often talc-filled; halogen-free where the OEM requires	UL 94 at the wall, plus glow wire under IEC or UL 60335-1 for parts near live connections
Terminal covers, connectors and parts holding live connections	V-0 with high GWIT and CTI 600 V	Glow wire (GWIT and GWFI), CTI, UL 94
Electrical installation boxes, cable ducts and power rails	V-2 or V-0, unfilled or talc-filled	UL 94 and the box or raceway product standard
Fans, blower housings and HVAC parts	V-0 or 5V-rated talc- or glass-filled grades	UL 94, sometimes 5VA, under the equipment standard
Automotive: fuse boxes, battery housings, EV battery supports	V-0, often glass-filled halogen-free	The OEM material spec, often UL 94 for battery and electrical parts. Vehicle interiors use FMVSS 302, a horizontal burn-rate test, not UL 94.
Building products: cavity wall boxes, lighting parts, public seating	V-2 or V-0, UV-stabilized for outdoor use	Building fire codes use their own tests, such as ASTM E84 in the U.S. and EN 13501 in Europe. UL 94 alone does not satisfy them.

Typical choices only. The end-product standard and your customer decide which rating, thickness and tests apply.

Substituting an FR PP grade, and what to put on the RFQ

An FR PP grade is only a valid substitute if its own UL yellow card, searchable in UL Product iQ, covers your rating at your thinnest wall and in your color, with the RTI, CTI and glow-wire values your product needs. Even then, the grade named in your end-product file or on the OEM’s approved list is the one the approval rests on, so a change can need a review or retest. The easiest route is a grade already listed as an alternate. Halogenated and halogen-free grades also shrink and process differently, so check critical dimensions.

The grade you run now, with its data sheet and UL file number if you have them.
Rating, thickness and color. For example V-0 at 1.5 mm in black, or 5VA at 3.0 mm in natural.
Glow wire, RTI and CTI values your product standard calls for, at the part’s thickness.
Halogen-free or not, with the definition (IEC 61249-2-21, UL 746H, UL 2885 or the customer’s own), plus RoHS, REACH, Prop 65 and PFAS statements.
Filler and base. Unfilled, talc or glass and the percentage; homopolymer or copolymer; MFR at 230°C / 446°F and 2.16 kg.
Part and service. What it is, whether it touches copper, runs hot or goes outdoors.
Quantity and ship-to city. Trial gaylords or production volume, and yearly usage.

Common questions

What is the difference between V-2 and V-0 polypropylene?

Both are UL 94 vertical burn ratings. V-0 bars must stop flaming within 10 seconds after each flame application, with no drips that ignite the cotton below. V-2 allows up to 30 seconds and flaming drips that ignite the cotton. V-2 PP needs only a small dose of flame retardant; V-0 PP needs far more, which raises density and lowers impact.

Is there halogen-free flame retardant polypropylene?

Yes. Halogen-free FR PP uses intumescent phosphorus and nitrogen systems, such as ammonium polyphosphate, and reaches V-2 or V-0, and 5VA in some filled grades. Ask which halogen-free definition the grade meets, since IEC 61249-2-21 and UL 2885 differ on fluorine and iodine.

Does V-0 polypropylene pass the glow-wire test?

Not automatically. Glow wire is a separate test. In one producer’s FR PP family, GWIT runs from 750°C to 850°C / 1,382°F to 1,562°F, so some V-0 grades miss the 775°C / 1,427°F often needed for parts near live connections in unattended appliances. Check GWFI and GWIT at your thickness.

What melt temperature should I run FR PP at?

Lower than standard PP. Our processing chart gives 190–274°C / 374–525°F for standard PP homopolymer, but FR grade sheets often set a lower ceiling, especially halogen-free grades. Follow the grade sheet, keep residence time short and purge when the press stops.

Can I add regrind or color to a UL-rated FR PP?

Within limits. UL 746D generally allows up to 25% in-house regrind of the same grade, and color concentrates generally have to be recognized for use with that grade. The listing is color-specific, so check the card first.

Can you match the FR PP grade in my UL file?

We quote the exact grade when it is available. When it is not, a polymer chemist checks a substitute’s yellow card against your rating, thickness, color, RTI, CTI and glow-wire values and tells you what differs. Your end-product approval may still need a review. We aim to send your quote within one to three business days.

If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.

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Flame retardant polypropylene, matched to your listing

Send the FR PP grade you run, or the rating, thickness, color and glow-wire values you need, and a polymer chemist matches a listed grade or a qualified equivalent and quotes it. We aim to send your quote within one to three business days.