Silica-Filled Rubber Mixtures With Low-Viscosity Processing Aid

Solution Overview

Problem

Existing tire rubber compounds face challenges in balancing rolling resistance, wet braking performance, and abrasion resistance, with the use of trimethylolpropane fatty acid mixtures leading to increased viscosity and toxicity concerns.

Innovation Solution

Incorporating a processing aid of formula (I) in rubber mixtures containing hydroxyl group-containing oxide fillers and sulfur-containing organic silanes, along with crosslinking agents, to improve performance without the toxicity of trimethylolpropane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If increasing amounts of silica and reinforcing additives are added to optimize application-relevant properties, then wet braking, rolling resistance, and abrasion resistance are improved, but Mooney viscosity increases significantly

Engineering Contradiction:

Improvewet braking performanceVSAvoidMooney viscosity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

A processing aid compound according to formula (I) is introduced as an intermediary substance between the silica-filled rubber matrix and the processing equipment. This compound mediates the interaction by adsorbing to silica surfaces and rubber chains, reducing direct friction and adhesion forces, thereby enabling efficient processing despite high filler content

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The processing aid compound changes the rheological parameters of the rubber compound by modifying the interaction between filler particles and rubber matrix. Through its molecular structure containing basic nitrogen atoms and hydroxyl groups, it alters the flow characteristics, reducing Mooney viscosity and enabling optimal processing conditions

Inventive Principle:

Principle #35Parameter changes

2Reliability

If trimethylolpropane (TMP) fatty acid mixture is used to improve rolling resistance and wet skid resistance, then application-relevant properties are enhanced, but toxicological harm increases due to TMP being classified as reprotoxic Category 2

Engineering Contradiction:

Improverolling resistanceVSAvoidreprotoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful TMP component is extracted and removed from the processing aid formulation. The invention replaces TMP-based compounds with novel structures according to formula (I) that eliminate the reprotoxic methylolpropane moiety while retaining the essential processing and performance-enhancing functions through alternative molecular architectures

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs processing aid compounds with optimized molecular structures that achieve the desired performance effect without relying on persistent toxic substances. The new compounds provide temporary processing assistance during vulcanization and then degrade or remain as harmless residues, replacing the persistent toxic TMP fatty acid mixtures

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If trimethylolpropane (TMP) fatty acid mixture is used to improve wet skid resistance, then application-relevant properties are enhanced, but toxicological harm increases due to TMP being classified as reprotoxic Category 2

Engineering Contradiction:

Improvewet skid resistanceVSAvoidreprotoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful TMP component is extracted and removed from the processing aid formulation. The invention replaces TMP-based compounds with novel structures according to formula (I) that eliminate the reprotoxic methylolpropane moiety while retaining the essential processing and performance-enhancing functions through alternative molecular architectures

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs processing aid compounds with optimized molecular structures that achieve the desired performance effect without relying on persistent toxic substances. The new compounds provide temporary processing assistance during vulcanization and then degrade or remain as harmless residues, replacing the persistent toxic TMP fatty acid mixtures

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4559967B1Rubber mixtures containing at least one process aid of formula (i)

Publication Date: 2026.05.06 LANXESS DEUTSCHLAND GMBH

AI summary

The invention relates to rubber mixtures comprising at least one rubber, at least one hydroxyl-containing oxidic filler, at least one reinforcing additive from the series of sulfur-containing organic silanes, at least one crosslinker from the series of sulfur and sulfur donors, and at least one processing aid of the formula (I), their preparation and use, and the vulcanizates obtainable thereby by the vulcanization process, in particular in the form of tires, parts of tires or technical rubber articles.