HVA-2 Application in Rubber Tire: The Ultimate Solution for Reversion and Shoulder Separation

-By Yangchen Advanced Materials – A Leading HVA-2 Manufacturer

If you are a tire compounder or a rubber technologist, you have probably faced two persistent nightmares:  reversion and shoulder separation. These issues not only reduce tire life but also increase warranty claims and damage brand reputation.

HVA-2 (N,N’-m-Phenylene bismaleimide) – also known as PDM or HA-8 – is a multifunctional rubber additive that effectively eliminates these problems. In this article, we will explore the HVA-2 application in rubber tire manufacturing, backed by real performance data, and explain why Yangchentech is your most reliable supply partner.

1.What is HVA-2?

HVA-2 is an aromatic bismaleimide with two reactive double bonds. It acts as:

• Anti-reversion agent in sulfur-cured natural rubber
• Co-agent in peroxide systems
• Adhesion promoter between rubber and cords
• Heat-resistant modifier for thick rubber articles

Its chemical structure allows it to form thermally stable carbon-carbon crosslinks, which do not break down under prolonged high-temperature vulcanization.

2.Why Does the Tire Industry Need HVA-2?

Modern tire manufacturing demands higher productivity (shorter cure times) and larger, heavier loads (more heat generation). Conventional sulfur vulcanization produces polysulfidic bonds that are stable only within a narrow temperature window. Once the temperature exceeds 150°C for extended periods (typical in thick tire components), reversion occurs: crosslinks break, network density drops, and mechanical properties collapse.

• Consequences of reversion in tires:
• Reduced tread stiffness and tear strength
• Shoulder separation – a common failure mode in bias truck tires
• Poor belt edge adhesion
• Lower retention of dynamic properties

HVA-2 solves this by generating hybrid crosslinks that resist thermal cleavage, maintaining torque even after 30 minutes at 170°C.

3.Key Benefits of HVA-2 Application in Rubber Tire

Eliminates Reversion – Proven by Data

With HVA-2, your tire compound stays robust even under severe overcure conditions.

Prevents Shoulder Separation in Bias Truck Tires

Adding 2–3 phr of HVA-2 to the shoulder pad and breaker compounds significantly improves the adhesion between natural rubber and nylon/polyester cords. The maleimide ring reacts with amino groups on the fiber surface, forming a covalent bond that withstands dynamic flexing and heat aging.

Result: Reduced scrap rates and fewer field failures.

Improves Heat Aging Resistance

HVA-2’s hybrid crosslinks do not revert, so the rubber retains its mechanical integrity after prolonged heat exposure. This translates into longer tire life for long-haul trucks and OTR vehicles.

Enhances Processing Safety

At low dosages (0.5–1.0 phr), HVA-2 acts as a scorch retarder, delaying Mooney scorch time by 15–20% without affecting cure rate. This gives you a wider processing window, especially during hot summer shop-floor conditions.