Modified Silica Composition for Lower-Viscosity Rubber Reinforcement

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Solution Overview

Problem

Modified silicas used in rubber mixtures often result in increased mixture viscosities, reduced processing windows, premature crosslinking, and adverse effects on dynamic properties and filler dispersion, leading to poorer processing characteristics and quality.

Innovation Solution

The development of modified silicas with specific physicochemical parameters, prepared by mixing silica with sulfur-containing alkoxysilane emulsions and polysiloxanes before drying, eliminating the need for additional conditioning steps and improving processing characteristics and dynamic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If modified silicas are used in rubber mixtures, then filler reinforcement is achieved, but mixture viscosity increases and processing characteristics deteriorate

Engineering Contradiction:
Improvefiller reinforcementVSAvoidprocessing characteristics
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the sulfur content (0.1-1.5 wt%, preferably 0.4-1.3 wt%) and carbon content (0.5-10 wt%, preferably 1-10 wt%) of the modified silica to optimize the balance between reinforcement and processability. By adjusting these compositional parameters, the invention achieves filler reinforcement while maintaining acceptable mixture viscosity and processing characteristics.

Inventive Principle:
Principle #35Parameter changes

2Strength

If modified silicas are used in rubber mixtures, then filler reinforcement is achieved, but processing window is reduced

Engineering Contradiction:
Improvefiller reinforcementVSAvoidprocessing window
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention uses parameter changes by optimizing the sulfur content range (0.1-1.5 wt%, preferably 0.4-1.3 wt%) to extend the processing window. This precise parameter control allows the rubber mixture to maintain stability across a broader range of processing conditions while achieving the desired reinforcement effect.

Inventive Principle:
Principle #35Parameter changes

3Strength

If modified silicas are used in rubber mixtures, then filler reinforcement is achieved, but premature crosslinking occurs

Engineering Contradiction:
Improvefiller reinforcementVSAvoidpremature crosslinking
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by strictly controlling the sulfur content within 0.1-1.5 wt% (preferably 0.4-1.3 wt%) to prevent premature crosslinking. This optimized sulfur level provides sufficient reinforcement while delaying unwanted crosslinking reactions during storage and processing, thereby improving mixture stability and reliability.

Inventive Principle:
Principle #35Parameter changes

4Strength

If modified silicas are used in rubber mixtures, then filler reinforcement is achieved, but dynamic properties are adversely affected

Engineering Contradiction:
Improvefiller reinforcementVSAvoiddynamic properties
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention uses parameter changes by optimizing the sulfur content (0.1-1.5 wt%, preferably 0.4-1.3 wt%) and carbon content (0.5-10 wt%, preferably 1-10 wt%) to improve dynamic properties. This precise compositional control enhances the interaction between filler and rubber matrix, leading to better dynamic performance while maintaining reinforcement.

Inventive Principle:
Principle #35Parameter changes

5Strength

If modified silicas are used in rubber mixtures, then filler reinforcement is achieved, but dispersion quality is worsened

Engineering Contradiction:
Improvefiller reinforcementVSAvoiddispersion quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the sulfur content (0.1-1.5 wt%, preferably 0.4-1.3 wt%) and carbon content (0.5-10 wt%, preferably 1-10 wt%) to optimize dispersion quality. These compositional adjustments improve the wettability and distribution of filler particles in the rubber matrix, achieving uniform dispersion while maintaining reinforcement effectiveness.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The modified silicas reduce Mooney viscosities, extend the processing window, and enhance dynamic properties, including elongation at break and dispersion quality, while maintaining tensile strength and abrasion resistance.

Implementation Method 1

mixing silica with at least one additive selected from the group of aqueous sulfur-containing alkoxysilane emulsions

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

mixing silica with at least one additive selected from the group of aqueous sulfur-containing alkoxysilane emulsions

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

mixing silica with at least one additive selected from the group of ... polysiloxanes such as preferably polydimethylsiloxane

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

supplied to the drying unit

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20230264964A1Modified silicas, process for preparation thereof and use thereof
Publication Date: 2023.08.24 EVONIK OPERATIONS GMBH

AI summary

Modified silicas, having the following physicochemical parameters: a CTABmod of <200 m2/g, a BETMP of 50-500 m2/g, a CTABmod-BETMP of <0 m2/g, a carbon content of >0.5% by weight, a modemod from CPS particle size determination of >50 nm, a d75mod from CPS particle size determination of 20-150 nm, a Rmin from Hg pore size determination, pressurized of <10 nm, and a sulfur content of ≤1.50% by weight.