ALNOVOL® PN 870: Enabling high-performance, CMR-free adhesion in technical rubber
From regulatory pressure to formulation redesign
In technical rubber applications, long-term performance is critically dependent on the quality of adhesion between rubber compounds and reinforcing substrates such as steel or textile cords. This is particularly true in tyres, belts, hoses and other safety-critical components.
Historically, robust adhesion has been achieved using
resorcinol-based novolac resins combined with cobalt salts
. While these systems offer reliable bonding performance, they present increasing challenges:
- Regulatory pressure on CMR substances under REACH continues to tighten, with restrictions on carcinogenic, mutagenic and reprotoxic materials expanding in scope and enforcement
- Resorcinol is under scrutiny as a Substance of Very High Concern ( SVHC )
- Cobalt salts carry health hazard classifications and are linked to supply risk, price volatility and ESG concerns
As a result, rubber compounders are actively seeking
drop-in alternatives
that
eliminate substances of concern without compromising performance.
ALNOVOL® PN 870: a next-generation adhesion promoter
ALNOVOL® PN 870 is a
modified phenolic novolac resin
developed to replace conventional resorcinol–cobalt adhesion systems in technical rubber formulations.
It is:
- Free from resorcinol and cobalt
- Label-free with respect to hazard classification
- Designed as an all-in-one adhesion promoter solution
The product enables compounders to meet regulatory and sustainability targets while maintaining operational continuity.
Performance parity without formulation complexity
A key barrier to replacing conventional adhesion systems is the risk of performance loss. ALNOVOL® PN 870 has been developed to address this directly.
Testing in natural rubber formulations shows:
- Rheology comparable to cobalt-containing systems , supporting unchanged processing behaviour
- Equivalent adhesion performance , including after heat ageing
- Stable mechanical properties , with no compromise in modulus, hardness or elongation
These results confirm that
performance-critical parameters
can be maintained while
removing both cobalt and resorcinol
from the formulation
Processing and formulation advantages
Beyond regulatory compliance, ALNOVOL® PN 870 delivers tangible formulation and processing benefits:
- Improved scorch resistance , enabling a broader processing window
- Enhanced reversion resistance , supporting durability in dynamic applications
- Better ageing performance , maintaining adhesion over time
- Higher crosslink density and more consistent curing behaviour
- Reduced performance variability across batches
From a compounding perspective, it can be incorporated in standard mixing processes and used at typical addition levels, without requiring fundamental changes to formulation design.
Health, environmental and supply chain impact
The transition to CMR-free adhesion systems is not only regulatory-driven but also aligned with broader sustainability and risk management objectives.
ALNOVOL® PN 870 supports:
- Removal of hazardous classifications associated with cobalt salts and resorcinol
- Reduced emissions and odour during processing, due to low free phenol content
- Improved worker safety and simplified handling requirements
- Reduced dependence on critical raw materials , mitigating supply chain volatility
This aligns with increasing expectations from OEMs and end-users for
transparent, safer material
selection across the value chain.
Application scope in technical rubber
ALNOVOL® PN 870 is suitable for a wide range of rubber applications requiring durable adhesion to reinforcement materials:
- Passenger and commercial vehicle tyres
- Conveyor belts and industrial rubber goods
- Hoses, seals and engineered elastomer components
- Textile- and steel-reinforced rubber systems
Phenolic adhesion promoters remain a core technology in these applications, providing
strong interfacial bonding and improved mechanical performance
. ALNOVOL® PN 870 builds on this foundation while addressing modern regulatory and sustainability requirements.
A practical route to CMR-free compounding
The shift away from cobalt and resorcinol is no longer a long-term ambition; it is an immediate requirement driven by regulation, supply risk and ESG targets.
ALNOVOL® PN 870 provides a
practical, validated pathway to CMR-free adhesion systems
, combining:
- Proven performance equivalence
- Simplified formulation strategy
- Improved safety and sustainability profile
For compounders, the key outcome is clear:
compliance and performance
can now be achieved simultaneously, without compromise or complexity.
Want to learn more about formulating with Alnovol® PN 870? Need some product recommendations to help you meet your formulating goals?
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