Conjugated Diene Rubber Siloxane Modification for Silica Affinity
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Solution Overview
Problem
Conventional methods for producing cross-linked rubbers using silica as a filler face challenges in achieving optimal low heat buildup and wet grip due to insufficient affinity between rubber and silica, leading to poor processability and increased manufacturing costs, especially when using silane coupling agents.
Innovation Solution
A method involving the reaction of siloxane with a conjugated diene polymer chain, followed by a compound with a 1,6-dioxa-2-silacyclooctane structure containing a tertiary amine group, to enhance the affinity and properties of the rubber, resulting in a cross-linked rubber with improved low heat buildup and wet grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If silane coupling agents are added to improve the affinity between rubber and silica, then the affinity is improved, but the manufacturing cost increases and advanced processing techniques are required
Solution Approach 1:
The rubber polymer itself is modified to possess silica affinity through reaction with siloxane and compound (1), enabling the rubber to self-bind with silica without requiring external silane coupling agents. This self-service approach eliminates the need for additional coupling agents and complex processing techniques while maintaining strong rubber-silica affinity
Solution Approach 2:
The modifying agents (siloxane and compound (1)) are incorporated into the rubber polymer during the polymerization process itself, before the rubber is compounded with silica. This preliminary modification ensures the rubber already possesses silica affinity when mixed, simplifying subsequent processing and eliminating the need for separate coupling agent addition steps
2Ease of manufacture
If conventional rubber is used with silica filler, then the manufacturing cost is lower, but the affinity between rubber and silica is insufficient leading to poor processability
Solution Approach 1:
The chemical structure of the rubber polymer is modified by incorporating siloxane and compound (1) during polymerization, changing the surface properties and chemical composition of the rubber to enhance its affinity for silica. This parameter change occurs at the molecular level, creating permanent chemical bonds between rubber and silica that improve processability without requiring expensive conventional coupling agents
3Loss of energy
If cross-linked rubber is produced for low fuel consumption, then rolling resistance is reduced, but wet grip becomes insufficient
Solution Approach 1:
The invention creates a composite structure where rubber polymer chains are chemically bonded to silica particles through the modifying agents. This rubber-silica composite material exhibits both low rolling resistance (due to strong interfacial bonding reducing energy loss) and excellent wet grip (due to silica's water dispersion properties and strong adhesion), simultaneously resolving the trade-off between these two performance parameters
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 method effectively improves the affinity between rubber and silica, leading to enhanced low heat buildup and wet grip in cross-linked rubbers, while reducing manufacturing costs and processing complexities.
Implementation Method 1
a second step of reacting siloxane with the conjugated diene polymer chain having an active end
Implementation Method 2
a third step of reacting a compound having a 1,6-dioxa-2-silacyclooctane structure where an 8-position is substituted by a tertiary amine structure-containing group to react with the conjugated diene polymer chain with which siloxane was reacted
Data Source
AI summary
There is provided a method of production of a conjugated diene rubber comprising a first step of polymerizing a monomer containing a conjugated diene compound in an inert solvent using a polymerization initiator so as to obtain a conjugated diene polymer chain having an active end, a second step of reacting siloxane with the conjugated diene polymer chain having an active end, and a third step of reacting a compound represented by the following general formula (1) with the conjugated diene polymer chain with which siloxane was reacted obtained in the second step: wherein, in the general formula (1), X1 represents a functional group selected from a hydrocarbyloxy group, halogen group, and hydroxyl group, R1 represents a substituted or unsubstituted hydrocarbon group, R2 and R3 respectively independently represent a substituted or unsubstituted hydrocarbon group, R2 and R3 may bond with each other to form a ring structure together with the nitrogen atom to which they are bound, when forming the ring structure they may form a ring structure together with a hetero atom other than the nitrogen atom to which they are bound in addition to the nitrogen atom to which they are bound, "r" is an integer of 0 to 2.