Bromine-Antimony vs Halogen-Free Flame Retardants: Differences, Modification Effects, and Plastic Material Selection Guide

Procurement Summary

Bromine-antimony and halogen-free flame-retardant systems can both help plastics reach flame-retardant targets, but they are suitable for different products.

For related DEYU material options, start from the flame-retardant plastics platform and compare specific V-0 engineering grades such as DGK-PC FR3000 flame-retardant PC when thickness, UL94 rating, impact retention and processing stability must be validated together.

Bromine-antimony systems are usually more efficient, easier to reach V-0 at lower loading in many resin systems, and often provide better cost-performance. They are commonly used in ABS, HIPS, PP, PBT, PC/ABS, and some engineering plastics when customer specifications allow halogenated systems.

Halogen-free systems are preferred when customers require low halogen, lower corrosive gas risk, environmental compliance, or electronics / new energy / export-oriented specifications. They are common in PP, PA6, PA66, PBT, PC/ABS, TPU, and TPE, but often require higher additive loading and more careful balance of impact strength, flowability, moisture resistance, color, and long-term stability.

The key selection point is not simply “which one is better.” The correct question is:

What flame rating is required? At what thickness: 0.8 mm, 1.5 mm, 2.0 mm, or 3.0 mm? Is UL94 V-0, V-1, V-2, HB, 5VA, GWIT, GWFI, or CTI required? Does the part also require impact strength, UV resistance, anti-static performance, wear resistance, color matching, or low warpage? Does the customer restrict halogens or antimony?

1. Core Difference Between Bromine-Antimony and Halogen-Free Systems

Item	Bromine-Antimony System	Halogen-Free System
Typical components	Brominated flame retardant + antimony trioxide	Phosphorus, nitrogen, mineral, intumescent, red phosphorus, or hybrid systems
Flame-retardant efficiency	Usually high	Medium to high, resin-dependent
Loading level	Often lower	Often higher
Mechanical retention	Often easier to retain	Needs careful formulation balance
Smoke / corrosive gas concern	Higher concern	Usually lower halogen-related concern
Color feasibility	Often good, but depends on system	Can be difficult with some systems
Processing stability	Mature route	More sensitive to moisture, dispersion, and processing
Cost	Often cost-effective	Often higher, especially high-performance grades
Typical use	Cost-sensitive industrial and electrical parts	Electronics, new energy, export, low-halogen applications

Both routes must be validated by actual test thickness. “V-0” without thickness is not a complete material specification.

2. Bromine-Antimony Flame-Retardant Route

Bromine-antimony systems work through a gas-phase flame inhibition mechanism. In practical compounding, they are widely used because of high efficiency and mature production experience.

Main Advantages

easier to reach UL94 V-0 in many plastics; lower additive loading than many halogen-free systems; good cost-performance; less loss of flowability in selected formulations; suitable for ABS, PP, HIPS, PBT, PC/ABS, and selected engineering plastics.

Main Limitations

halogen restriction may apply in some industries; smoke and corrosive gas concerns during combustion; antimony trioxide may be restricted by some customer specifications; not always suitable for low-smoke, halogen-free, or export-oriented requirements.

Suitable Scenarios

electrical housings where halogen is allowed; industrial parts requiring stable V-0; cost-sensitive flame-retardant ABS or PP; black or colored industrial covers; applications where mechanical retention and cost are both important.

3. Halogen-Free Flame-Retardant Route

Halogen-free flame retardants usually rely on condensed-phase char formation, intumescent protection, phosphorus-nitrogen synergy, mineral dilution, or resin-specific flame-retardant chemistry.

Main Advantages

suitable for halogen-free specifications; lower halogen-related corrosive gas concern; preferred in many electronics, new energy, rail, export, and environmentally sensitive applications; can be combined with low-smoke requirements depending on system.

Main Limitations

higher loading may be needed; impact strength may decrease; flowability may become worse; water resistance and moisture sensitivity must be checked; some systems affect color, surface, or mold deposit; processing window can be narrower.

Suitable Scenarios

halogen-free PP electrical parts; halogen-free PA6 / PA66 connectors; halogen-free PBT electrical components; battery-related components; charging equipment; products with customer restrictions on halogen or antimony.

4. What Effects Can Flame-Retardant Modification Achieve?

Flame-retardant modification can improve fire performance, but it may also affect mechanical and processing properties. The final result depends on resin, additive system, thickness, color, filler, and process.

Performance Target	Possible Result After Modification	Key Risk
UL94 rating	HB, V-2, V-1, V-0, 5VB, 5VA depending on material and thickness	Rating must be tested at specified thickness
Glow wire	Improved GWFI / GWIT direction in selected systems	Resin and formulation dependent
CTI	Can be maintained or improved in selected halogen-free systems	Some additives reduce CTI
Impact strength	Can be retained with impact-balanced formulation	Flame retardants often reduce impact
Flowability	Can be adjusted by resin and additive balance	High loading may reduce flow
Color	Black, natural, gray, or custom color possible	Some systems limit light color
UV resistance	Can be combined with UV package	FR + UV must be validated together
Anti-static / conductive	Can be combined in special systems	FR and conductive fillers may conflict
Low warpage	Can be improved by filler balance	Reinforcement may cause anisotropic shrinkage

A realistic material specification should include both flame rating and mechanical targets.

5. Material-Specific Selection Guide

ABS

Common route:

bromine-antimony flame-retardant ABS; halogen-free ABS in selected applications; FR ABS + high impact; FR ABS + antistatic.

Selection note:

ABS can reach flame-retardant targets efficiently with brominated systems. Halogen-free ABS is more difficult and usually needs careful validation of impact and processing.

PP

Common route:

bromine-antimony FR PP; halogen-free intumescent PP; FR PP + glass fiber; FR PP + UV; FR PP + anti-static or conductive.

Selection note:

Halogen-free PP is widely used but often needs higher loading. Flowability, impact strength, water resistance, and surface quality should be checked.

PC/ABS

Common route:

halogenated FR PC/ABS; phosphorus-based halogen-free PC/ABS; UV FR PC/ABS; ESD FR PC/ABS.

Selection note:

PC/ABS is often selected for electrical housings because it balances impact, heat resistance, processability, and flame retardancy. Halogen-free routes must balance hydrolysis, impact retention, and color.

PA6 / PA66

Common route:

halogen-free phosphorus-nitrogen systems; red phosphorus systems for selected nylon applications; glass fiber reinforced FR nylon; FR nylon + high strength; FR nylon + conductive or antistatic.

Selection note:

Nylon requires attention to moisture conditioning, glass fiber interface, impact retention, and electrical properties. For connectors and structural parts, CTI and mechanical retention are often as important as UL94.

PBT / PET

Common route:

brominated FR PBT; halogen-free FR PBT; glass fiber reinforced FR PBT; electrical-grade FR PBT.

Selection note:

PBT is common in electrical components. CTI, warpage, hydrolysis resistance, and thin-wall flame rating should be checked together.

6. Purchasing Guide: How to Write a Clear FR Material Inquiry

A professional inquiry should include:

base resin: PP / ABS / PC/ABS / PA66 / PBT; flame-retardant route preference: bromine-antimony allowed or halogen-free required; target rating: HB, V-2, V-0, 5VA, GWIT, GWFI; test thickness: 0.8 mm / 1.5 mm / 2.0 mm / 3.0 mm; mechanical targets: impact, tensile, flexural modulus; color: black, natural, white, gray, custom color; processing method: injection molding or extrusion; additional functions: UV, anti-static, conductive, wear-resistant, low warpage; customer standard: UL94, glow wire, CTI, RoHS, REACH, halogen-free requirement; current problem: cracking, poor flow, unstable V-0, color shift, warpage, brittle failure.

This avoids the common problem of asking only for “flame-retardant plastic” without enough engineering information.

7. Customer Case 1: Bromine-Antimony FR ABS Housing

Original Situation

A customer used ordinary ABS for an electrical housing. The part had good appearance and impact strength, but could not meet the required flame-retardant level.

Original Data

Item	Ordinary ABS
UL94 target	V-0 direction at 1.5 mm
Actual result	Failed V-0
Notched impact	20 kJ/m²
Surface appearance	Good
Flowability	Good
Cost target	Sensitive

DEYU Improvement Plan

DEYU recommended a DGK bromine-antimony flame-retardant ABS formulation.

Development focus:

V-0 direction at specified thickness; impact retention; surface appearance; flowability; cost control.

Debugging Process

First trial reached flame-retardant direction, but impact dropped more than expected.

Adjustment:

optimized brominated FR dosage; adjusted antimony balance; added impact balance modifier; improved dispersion.

Second trial improved impact but showed slight surface mark.

Adjustment:

modified processing stabilizer; optimized injection temperature; adjusted color masterbatch compatibility.

Final Result

Item	Ordinary ABS	DEYU FR ABS
UL94 target	V-0 direction at 1.5 mm	V-0 direction by validation
Notched impact	20 kJ/m²	16.5 kJ/m²
Surface appearance	Good	Good
Flowability	Good	Acceptable
Cost	Low	Controlled
Production stability	General	Stable after process tuning

Case Conclusion

For cost-sensitive ABS electrical housings where halogen is allowed, bromine-antimony FR ABS is often a practical route. The key is balancing V-0 performance with impact and surface quality.

8. Customer Case 2: Halogen-Free FR PP for Electrical Tray

Original Situation

A customer required a halogen-free PP material for an electrical tray. The original flame-retardant PP used a halogenated system, but the customer’s export specification required halogen-free material.

Original Data

Item	Original Halogenated FR PP
UL94 target	V-0 direction at 2.0 mm
Impact performance	Acceptable
Flowability	Good
Halogen-free requirement	Not met
Warpage	Medium
Surface quality	Good

DEYU Improvement Plan

DEYU recommended a DGK halogen-free flame-retardant PP formulation.

Development focus:

halogen-free requirement; V-0 direction at 2.0 mm; flowability retention; impact balance; warpage control; surface quality.

Debugging Process

First trial met the halogen-free direction but flowability decreased.

Adjustment:

optimized PP base resin; adjusted intumescent FR package; improved melt flow balance.

Second trial improved flow, but impact was lower than required.

Adjustment:

added impact modifier; controlled FR dispersion; adjusted cooling and holding pressure.

Final Result

Item	Original Halogenated FR PP	DEYU Halogen-Free FR PP
Halogen-free requirement	Not met	Met by customer requirement
UL94 target	V-0 direction at 2.0 mm	V-0 direction by validation
Impact performance	Acceptable	Acceptable after adjustment
Flowability	Good	Medium-good
Warpage	Medium	Reduced after filler balance
Surface quality	Good	Acceptable-good

Case Conclusion

Halogen-free PP can meet electrical application requirements, but it needs more formulation balance than ordinary halogenated PP. Flowability, impact, and warpage should be validated together.

9. Customer Case 3: Halogen-Free FR PA66 Connector

Original Situation

A connector customer needed glass fiber reinforced PA66 with halogen-free flame retardancy. The part also required stiffness, dimensional stability, and electrical reliability.

Original Data

Item	Standard PA66-GF
UL94 target	V-0 direction at 0.8–1.5 mm
Tensile strength	135 MPa
Flexural modulus	7,800 MPa
CTI requirement	Required
Warpage	Must be controlled
Moisture effect	Needs validation

DEYU Improvement Plan

DEYU recommended a DGK halogen-free FR reinforced PA66 compound.

Development focus:

halogen-free FR system; glass fiber reinforcement; CTI direction; dimensional stability; impact retention; moisture conditioning validation.

Debugging Process

First trial reached flame-retardant direction but impact was low.

Adjustment:

optimized nylon FR package; improved glass fiber interface; added toughness balance.

Second trial improved impact, but warpage required correction.

Adjustment:

adjusted reinforcement ratio; improved mold temperature recommendation; balanced flow and packing.

Final Result

Item	Standard PA66-GF	DEYU Halogen-Free FR PA66-GF
Flame-retardant target	Not stable	V-0 direction by required thickness validation
Tensile strength	135 MPa	125 MPa
Flexural modulus	7,800 MPa	7,400 MPa
Impact retention	General	Improved after toughening
CTI direction	Required	Designed for customer validation
Warpage	Medium	Reduced after process adjustment

Case Conclusion

For nylon connectors, flame retardancy alone is not enough. CTI, strength, warpage, moisture conditioning, and glass fiber interface must be considered together.

10. DEYU DGK Flame-Retardant Material Platform

DEYU Plastics can develop flame-retardant compounds according to resin, thickness, flame rating, mechanical targets, and customer restrictions.

Solution Directions

DGK-FR PP bromine-antimony series; DGK-FR PP halogen-free series; DGK-FR ABS brominated series; DGK-FR PC/ABS halogen-free series; DGK-FR PA6 / PA66 halogen-free reinforced series; DGK-FR PBT electrical series; DGK-FR TPU / TPE flexible series; FR + UV materials; FR + antistatic materials; FR + conductive materials; FR + low-warpage materials; FR + high-impact materials.

Information Buyers Should Provide

base resin; application; required flame rating; test thickness; bromine-antimony allowed or halogen-free required; color; impact requirement; flowability requirement; CTI / glow wire requirement; UV, antistatic, conductive, or wear requirement; part drawing or sample; customer test standard.

Conclusion

Bromine-antimony and halogen-free flame-retardant systems are both important in plastic modification. Bromine-antimony systems are efficient, mature, and cost-effective in many ABS, PP, PBT, and PC/ABS applications where halogenated systems are allowed. Halogen-free systems are more suitable for customers requiring low-halogen, electronics, new energy, export, or environmental specifications, but they usually require more careful balancing of loading, impact strength, flowability, moisture resistance, color, and cost.

A professional flame-retardant material selection should always define resin, thickness, target rating, mechanical performance, color, processing method, and regulatory requirement. “V-0” without thickness and test condition is not a complete specification.

DEYU Plastics provides DGK flame-retardant modified materials based on PP, ABS, PC/ABS, PA6, PA66, PBT, TPU, TPE, and other systems. The recommended approach is to choose the flame-retardant route according to the final part requirement, not only according to additive name.