KonnArk Polymers Fulfilling Demand for Halogen-free and Low Smoke Materials; Complying With International Standards

In an exclusive interaction with Wire & Cable India, Mr. Murli Ballan, Director, KonnArk Polymers Private Limited, underscored the cable industry’s move toward halogen-free and low smoke materials in response to rising fire safety standards. To support this transition, the company has developed flame-retardant compounds engineered for efficient processing in high-speed extrusion lines and compatibility with crosslinking technologies such as e-beam and silane grafting. Designed to withstand elevated temperatures and mechanical stress, these compounds deliver enhanced thermal stability and mechanical integrity compared to conventional vinyl-based insulation systems, while complying with international fire safety standards, including CPR Euroclass B2ca, C1a, and other applicable standards.

Wire & Cable India: As infrastructure projects like metro rails and smart cities expand with stricter fire safety protocols, which of your current compounds are specifically engineered to meet cable manufacturers’ fire performance requirements, and what cable types or sectors are they most suited for?

Murli Ballan: SAB’s thermoplastic material SABIX® is used in railway cables, offering features like halogen-free, no flame propagation, flame retardant, and self-extinguishing properties. These cables meet EN 45545-2 standards and are suitable for railway construction, bogie, jumper cable, or sensor cable applications.

LSZH (Low Smoke Zero Halogen) materials, used by Prysmian Group, offers LSZH fire-rated cables for critical applications, including metro rail and aviation projects. These cables are designed to reduce smoke and toxic gas emissions during fires.

SABIX R 605 FRNC, R 615 FRNC, and R 645 FRNC TP data cables satisfy NFPA 130 and EN 45545-2 standards, making them suitable for fixed, protected installations in trains and rail systems.

These compounds are suited for various sectors, including railway and metro, smart cities, and – industrial applications.

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WCI: How are you leveraging halogen-free flame retardants, mineral fillers like ATH or MDH, or phosphorus-based systems in your fire-safe formulations to align with cable manufacturers’ processing capabilities and fire safety needs?

MB: The cable industry is shifting towards halogen-free solutions, and manufacturers are leveraging various technologies to meet fire safety needs.

HFFRs like aluminum trihydrate (ATH) and magnesium hydroxide (MDH) are widely used due to their low cost, environmental friendliness, and low smoke generation. These mineral fillers release water vapor when heated, cooling the material and reducing flammability. ATH and MDH are used in power cables for their thermal stability and flame retardancy.

Combining different HFFRs, like ATH and MDH, or adding synergists like zinc borate, enhances performance and reduces loading levels. Surface-treated HFFRs and nano-technology improve dispersion, compatibility, and overall performance in polymer matrices. These technologies are used in various cable applications, including power cables, communication cables, and automotive cables. HFFRs and synergistic blends are used in automotive cables for their thermal stability and resistance to harsh environments.

Phosphorus-based flame retardants, such as red phosphorus, ammonium polyphosphate (APP), and phosphate esters, are also popular. They work by promoting char formation, which limits oxygen access and slows combustion. Intumescent systems, combining a carbon source, acid source, and blowing agent, expand when exposed to heat, creating a protective char layer. Phosphorus-based systems and intumescent systems are used in communication cables for their low smoke and toxicity.

WCI: Cable manufacturers report varying levels of success with newer fire-resistant compounds in high-speed production environments. How do your fire-retardant compounds perform in high-speed extrusion or when used with crosslinking processes like e-beam or silane grafting?

MB: Our fire-retardant compounds are designed to perform well in high-speed extrusion and with crosslinking processes like e-beam or silane grafting. For instance, silane-grafted polyolefins have shown excellent flexibility and handleability, making them suitable for high-speed production environments.

These compounds maintain their fire-resistant properties even when subjected to high temperatures and mechanical stress. The use of silane crosslinking, in particular, offers improved physical and thermal characteristics compared to traditional vinyl insulation coatings.

Some key benefits of our fire-retardant compounds include improved flexibility, enhanced fire resistance, and high-temperature stability. Our fire-retardant compounds are suitable for various cable applications, including power cables, communication cables, and automotive cables.

WCI: Metro rail projects increasingly specify low smoke and toxicity requirements alongside mechanical durability standards. What breakthroughs have you made to help cable manufacturers in reducing smoke density and toxicity without compromising mechanical integrity in LSZH compounds?

MB: Metro rail projects are prioritizing low smoke and toxicity requirements alongside mechanical durability standards. To address this, breakthroughs have been made in LSZH (Low Smoke Zero Halogen) compounds.

LSZH compounds can achieve smoke density (Ds-4) values of ≤300, meeting EN45545 standards. This is accomplished through the use of organophosphorus compounds like BPADP, which significantly decrease smoke density and heat release. These compounds produce minimal toxic gases when burned, ensuring a safer environment. The addition of PC-siloxane copolymers improves mechanical properties like impact resistance and flowability without compromising smoke density. These advancements enable LSZH compounds to meet stringent requirements for metro rail projects, ensuring safety and durability.

WCI: Global export markets demand varying certification standards while domestic requirements continue evolving. Are your compounds developed and certified in direct response to cable manufacturers’ compliance needs for CPR Euroclass B2ca, C1A, or other international fire safety standards? How do you support them in regional compliance efforts?

MB: Our compounds are developed and certified to meet various international fire safety standards, including CPR Euroclass B2ca, C1A, and others. We work closely with cable manufacturers to ensure our products comply with regional requirements, such as EN 50575 for European markets and IEC 60331 for global standards.

Some of our certified compounds include Halogen-Free Flame Retardants (HFFRs)- meeting CPR B2ca and Cca standards for low smoke and toxicity; phosphorus-based systems- Complying with IEC 60331 for fire resistance; intumescent systems- Expanding to create a protective char layer, meeting CPR B2ca standards.

We support regional compliance efforts through customized formulations where tailored compounds meet specific standards and applications. We also ensure testing and certification by collaborating with notified bodies to ensure compliance, and provide technical expertise and guidance on material selection and processing. Our products are designed to meet stringent fire safety requirements, including CPR Euroclass B2ca, C1A, and others.

WCI: The tender specification process for infrastructure projects often requires collaborative material development. Can you share a recent example where you developed or customized a fire-retardant compound for a cable manufacturer’s specific project or tender requirement?

MB: A recent example of collaborative material development for a cable manufacturer’s specific project involves creating a fire-retardant cable material using a combination of polyethylene, ethylene propylene diene monomer, kaolin, calcium carbonate, and a flame retardant. The flame retardant is a nitrogen-phosphorus flame retardant and modified magnesium hydroxide, which provides good flame retardant and mechanical properties.

The preparation method involves: Mixing that combines polyethylene, ethylene propylene diene monomer, kaolin, calcium carbonate, and flame retardant in a reaction kettle; stirring and heating that involves stirring for 30 minutes at 1000rpm and mixing for 15 minutes at 130°C; and extrusion by adding the mixture to a double-screw extruder for extrusion granulation.

This customized compound meets specific project requirements, such as low smoke density and toxicity, while maintaining mechanical integrity.

WCI: Advanced material science applications are beginning to appear in commercial fire-resistant formulations. Are you working with nano-fillers, intumescent systems, or synergistic blends that go beyond traditional ATH-based flame retardants, specifically to enhance fire resistance in cables?

MB: Advanced material science is indeed revolutionizing fire-resistant formulations. We’re seeing significant advancements in nano-fillers, intumescent systems, and synergistic blends that surpass traditional ATH-based flame retardants.

For Nano-fillers, carbon nanotubes (CNTs) and graphene oxide (GO) are being used to enhance thermal stability and flame retardancy. For instance, a combination of CNTs and GO has shown to increase the tensile strength of polyacrylonitrile (PAN) copolymer from 26.8 to 52.53 MPa.

Intumescent Systems, like ammonium polyphosphate (APP) and melamine, expand when exposed to heat, creating a protective char layer. Researchers have developed TA-modified CNTs wrapped on APP, which improved the limiting oxygen index (LOI) of natural rubber (NR) composites to 28.6% and achieved a V-0 rating in UL-94 tests.

Synergistic blends such as combining phosphorus-containing flame retardants with CNTs or graphene have shown enhanced flame retardancy and smoke suppression. For example, a blend of SiAPP and aMWCNT reduced the peak heat release rate (PHRR) of polystyrene composites by 53.7%.

These advancements are being applied to enhance fire resistance in cables, ensuring safer infrastructure and compliance with evolving regulations.

WCI: Circular economy principles are reshaping material selection processes throughout the value chain. How are you addressing environmental concerns in fire-retardant compounds—whether through halogen-free formulations, recyclable blends, or bio-based additives?

MB: Circular economy principles are driving innovation in fire-retardant compounds, and there are several approaches being explored to address environmental concerns.

Many manufacturers are shifting towards halogen-free flame retardants, which are more environmentally friendly and reduce toxic emissions during combustion. Phosphorus-based compounds, such as DOPO derivatives, are popular alternatives.

Moreover, bio-based flame retardants, like tannic acid, phytic acid, and lignin, are gaining traction due to their renewable origin, low toxicity, and excellent char-forming capabilities. Researchers are also developing recyclable blends that combine bio-based polymers with flame retardants, enabling the creation of sustainable, fire-resistant materials.

Some notable examples include starch-based flame retardants, phytic acid-based flame retardants, lignin-based flame retardants. These advancements aim to reduce the environmental footprint of fire-retardant compounds while maintaining their effectiveness.

WCI: The gap between laboratory certification and field performance remains a discussion point in industry forums. What kind of feedback do you typically receive from cable manufacturers regarding fire performance in terms of what works well, and what still needs improvement?

MB: The gap between laboratory certification and field performance is a common discussion point. Based on industry feedback, what works well is Halogen-free flame retardants (HFFRs) that perform well in reducing smoke and toxicity. Further, intumescent systems provide effective fire protection in various applications. Laboratory testing (e.g., UL 94, LOI) often predicts performance, but field conditions can be more challenging.

Some of the areas for improvement are durability, smoke suppression, mechanical integrity, real-world scenarios. Cable manufacturers often highlight the need for more realistic testing by simulating real-world conditions to bridge the gap between lab and field performance. Material compatibility is another significant aspect ensuring flame retardants work well with various cable materials and designs.Lastly, long-term performance with verifying durability and fire resistance over the cable’s lifespan.

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WCI: Material science innovation continues driving performance advances while addressing processing challenges. From a compounder’s perspective, what’s the next big leap needed in fire-safety material science to meet the cable industry’s evolving needs?

MB: The next big leap in fire-safety material science is expected to come from advancements in nanotechnology, intumescent systems, and synergistic blends. These innovations will enhance fire resistance, reduce smoke and toxicity, and improve mechanical integrity. Some key areas of focus include:

Ceramic Insulation Technology: Allows cables to function even when the outer insulation melts, ideal for critical applications like emergency lighting and alarm systems.

Smart Cables with Sensors: Detect and report abnormalities like excessive heat, enabling proactive measures to prevent fires.

Eco-Friendly and Sustainable Materials: Low-smoke, zero-halogen (LSZH) materials and bio-based flame retardants are gaining traction.

Lightweight and Flexible Designs: Easier installation without compromising fire resistance.

Predictive Maintenance: Smart technology integration enables real-time monitoring and scheduled repairs.
The cable industry is also looking at AI-powered fire detection and clean agent suppression systems to enhance safety.