Sulfur-Crosslinkable Rubber Mixture Silane Coupling
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Solution Overview
Problem
Existing rubber mixtures for pneumatic vehicle tires face challenges in achieving a balance between rigidity, rolling resistance, wet grip, and processability, often requiring trade-offs between these properties.
Innovation Solution
A rubber compound comprising diene rubber, specifically solution-polymerized styrene-butadiene rubber, combined with silicic acid and a silane with an organic spacer group that enhances the bonding between silica and polymer chains, improving stiffness and the trade-off between rolling resistance and wet grip while maintaining processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the network node density of the vulcanized rubber compound is increased to improve handling behavior, then the stiffness of the rubber compound increases, but the tear properties and wet grip indicators deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific silane coupling agents with organic spacer groups and controlling the silica content (10-200 phr) and silane content (2-20 phr), which modifies the crosslinking mechanism to achieve improved stiffness without compromising tear resistance
Solution Approach 2:
The patent creates a composite rubber compound combining diene rubber with silica filler and silane coupling agents, where the silane forms a bridging structure between silica particles and rubber chains, producing a synergistic effect that simultaneously improves stiffness and maintains tear properties
2Strength
If the degree of filling is increased to improve handling behavior, then the stiffness of the rubber compound increases, but the rolling resistance increases
Solution Approach 1:
The patent optimizes the filler content within 10-200 phr ranges and modifies the chemical interaction parameters through silane coupling agents, creating a filler-rubber interface that provides reinforcement without excessive friction, thereby reducing rolling resistance while maintaining stiffness
Solution Approach 2:
The silane coupling agent acts as an intermediary between silica filler and rubber polymer chains, facilitating strong chemical bonding that improves stiffness efficiency, allowing lower filler content to achieve the same stiffness, thereby reducing rolling resistance
3Loss of energy
If silica is bonded to polymer chains by means of silane coupling agents, then the rolling resistance behavior improves, but the processability may be adversely affected
Solution Approach 1:
The patent carefully controls the silane content (2-20 phr) and selects silanes with specific organic spacer groups that provide optimal balance between bonding strength and processing characteristics, ensuring good processability while achieving low rolling resistance
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 rubber mixture exhibits increased rigidity and improved performance in handling, rolling resistance, and wet grip, with optimized processability, leading to better tire performance and manufacturing ease.
Implementation Method 1
the silicic acid is bonded to the polymer(s) by means of silane coupling agents
Implementation Method 2
Sulfur-crosslinkable rubber mixture
Data Source
AI summary
The invention relates to a sulfur-crosslinkable rubber mixture, especially for pneumatic tires for motor vehicles, and to a pneumatic tire. The rubber mixture comprises at least the following constituents: at least one diene rubber and 10 to 200 phr of at least one silica and 2 to 20 phf of at least one silane having the general empirical formula (I) [(R1)3Si-X]mSn(R2)2-m where the R1 radicals within a molecule may be the same or different and are alkoxy groups having 1 to 10 carbon atoms or cyclic dialkoxy groups having 2 to 10 carbon atoms or cycloalkoxy groups having 4 to 10 carbon atoms or phenoxy groups or halides, and where m assumes the value of 1 or 2 and where n is an integer from 1 to 8 and where R2 is a hydrogen atom or an acyl group having 1 to 20 carbon atoms and where X is an organic spacer group having 3 to 30 carbon atoms and containing at least one organic radical selected from the group consisting of: a) at least one allyl group and b) at least one phenyl group which has linkages to the silicon atom of the silyl group (R1)3Si- and to a sulfur atom of the Sn group via an alkyl radical having 0 to 20 carbon atoms in the 1,2 positions relative to one another, and which may bear further substituents, and c) at least one phenyl group which has linkages to the silicon atom of the silyl group (R1)3Si- and to a sulfur atom of the Sn group via an alkyl radical having 0 to 20 carbon atoms in the 1,3 positions relative to one another, and which may bear further substituents, and d) at least one phenyl group which has linkages to the silicon atom of the silyl group (R1)3Si- and to a sulfur atom of the Sn group via an alkyl radical having 0 to 20 carbon atoms in the 1,4 positions relative to one another and which additionally bears at least one further substituent, and e) fused aromatic ring systems which have linkages to the silicon atom of the silyl group (R1)3Si- and to a sulfur atom of the Sn group via an alkyl radical having 0 to 20 carbon atoms and which may additionally bear at least one further substituent.