Low-smoke Halogen-free Flame Retardants

Increasing Demand in Safety Cable Applications in the Construction and Defense Industry to Drive the Market

Low-smoke halogen-free flame retardants (LS HFFR) are majorly used in the wire and cable industry for cable jacketing purposes. LSOH cable jacketing is custom compounded to produce minimal smoke and low toxicity when exposed to fire. Most network cables (CAT5, CAT6, etc.) are insulated with: 
 

• Polyvinyl chloride (PVC)
• Polyethylene , or
• Thermoplastic urethane (TPU)

When in contact with fire, halogen-containing plastic releases hydrogen chloride, poisonous gas that forms hydrochloric acid when it comes in contact with H₂O. Low-smoke zero-halogen cables do not produce this toxic combination of gas, acid, and smoke when exposed to flame. Since no harmful smokes are released, LS HFFR cables are often used where safety, along with performance and reliability, is critical. They are typically specified for use in densely populated, enclosed public spaces where flame-resistance, low smoke production, and reduced toxic gas emissions during combustion are critical. 

The major applications for LS HFFR have confined spaces, such as residential and industrial buildings, with large amounts of cables in close proximity to people or sensitive electronic equipment. The military was one of the first adopters of LS HFFR standards. Mass transit and central office facilities are common applications for LS HFFR, and many telecommunication standards require low-smoke zero-halogen cables. 

Low-smoke zero-halogen compounds also comply with the European Union's Restriction of Hazardous Substances (RoHS) directive and similar North American safety and environmental standards.

Stringent Regulations Against Halogenated Flame Retardants Drive the LS HFFR Market

Most of the flame retardants are halogenated. These halogenated flame retardants along with other additives antimony trioxide and zinc-based substances are highly toxic in nature as they produced harmful gases/fumes on exposure to fire. In the event of a fire, the halogenated flame retardants also generate a lot of smoke which can reduce visibility and make evacuation difficult from premises or public vehicles. 

Few brominated and chlorinated flame retardants have been phased out of use because of environmental and human health and safety concerns but some are still being used. With the increasing environmental consciousness and growing concern about safety, there is a need to switch to low-smoke halogen-free flame retardants that adhere to environmental regulations. In the construction and automotive industry, there are strict fire and smoke regulations all around the world. 

In Europe, all electrical and electronic equipment in a train is approved according to EN 45545-2 of the European Railway Standard for Fire Safety. In a fire, low smoke density, without opacity, is a key figure and important in allowing passengers and staff in railway vehicles to escape and be rescued safely. In February 2020, the European Union imposed a ban on halogenated flame retardants in electronic displays and plastic enclosures. According to REACH and RoHS, electronic displays will not be allowed to contain brominated fire retardants or halogenated flame retardants. 

Regulators like WEEE (Waste Electric and Electronic Equipment) and SVHC (Substances of Very High Concern), with inputs from some NGOs, have also helped to boost the demand for halogen-free flame retardants by setting certain standards (such as Underwriters Laboratories (UL), horizontal & vertical burn ratings, and glow wire testing). 

In the US, many states have also banned halogenated flame retardants due to their toxic effects on the environment. This shift towards more environment-friendly alternatives will increase the demand for low-smoke halogen-free flame retardants, which, in turn, will drive market growth.
 

Stringent Government Rules Against Toxic Halogenated Flame Retardants to Drive Market Growth

Advanced Low-smoke Halogen-free Flame Retardants with Nano-fillers & Special Lubricants will be the New Trend

For low-smoke zero halogens, the cable jacket must be incorporated with a high percentage of filler material. This increase in filler material could make the jacket less chemical and water-resistant which reduces its mechanical and electrical properties than a non-LSZH counterpart. LSZH jackets experience cracking during installation, so special lubricants may be necessary to avoid damage. This is especially true in cold environments. 

LSZH has limited flexibility which makes it unsuitable for robotic or continuous flex applications. As a result, LSZH cable is commonly chosen for applications where fire safety is more of a concern than the cable's specific electrical and mechanical properties. Recent advancements in compound materials and processing have decreased some of these issues.

Nanofillers are being added to the thermoplastics. The main advantages are: 
 

• Lightweight
• Decreased gas permeability
• High modulus & strength
• Increased solvent resistance, and
• Increased thermal stability

These properties add benefit to the polymer matrix. 

In 2014, NANOFRABS was developed under the European FP7 research project. Effective halogen-free flame retardant for ABS compound was prepared by incorporating 20 nano-fillers. These ABS compounds are widely used in the electrical appliances sector.

Currently, lubricants like zinc stearate, calcium stearate, magnesium stearate, and low-molecular-weight wax are preferred in small quantities (~0.2%- 0.5%) for the polyolefin/ polyethylene matrix to provide flexibility to the material.

 

High-performance Cable Variant in Hybrid and Fully Electric Vehicles will be in High Demand
 

In 2020, Toyota sold 3 million hybrid electric cars and had set a target of 5.5 million for the year 2030. Despite the challenging year, Volkswagen recorded a sale of 212,000 electric cars, which was more than that of the 2019 sales.

Due to the rise in the growth of hybrid and electric vehicles in the forecasted year, it is estimated that the demand for charging cables and polymers for interior and exterior will also increase. These charging cables will need to be flame retardant with zero-halogen and low-smoke emission. Therefore, the demand for low-smoke halogen-free flame retardants for cables and polymeric components will increase in the future.
 

Note: CAGRs are provided in terms of volume

High Cost Could be a Major Challenge
 

The conventional cable is much cheaper than that of low-smoke halogen-free flame-retardant cables. Many countries in the Asia Pacific and the Middle East and Africa where regulations are not strict regarding LSZH jacketed cable will continue to use a cheap variety of conventional cables. Moreover, the current generation of LSZH cables has not yet established a proven history of long-term performance, which makes the customers opt for the traditional one.