Rubber Composition Mixing with Controlled Roll Nip
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Solution Overview
Problem
Current rubber compositions for tires, particularly snow tires, face challenges in achieving a balance between grip on snowy roads and stability on normal roads due to the mechanical action during mixing, which shortens reinforcing fibers and affects performance.
Innovation Solution
A production method involving the incorporation of reinforcing fibers, such as basalt, glass, or carbon fibers, into a rubber composition using a mixer with a roll nip equal to or above the volume average length of the fibers, ensuring their length is maintained in the mixed and cured states, along with a diene elastomer matrix and reinforcing inorganic fillers like silica, to enhance performance balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reinforcing fibers are incorporated into rubber composition using conventional mixing methods, then the rubber composition gains strength and structural reinforcement, but the mechanical action during mixing chops the fibers into much smaller lengths, reducing their effectiveness
Solution Approach 1:
The patent changes the physical parameters of the mixing process by controlling the roll nip distance to be equal to or greater than the volume average length of the reinforcing fibers. This parameter change prevents the mechanical chopping effect while still achieving thorough mixing, thereby maintaining both fiber length and composition homogeneity
Solution Approach 2:
The patent introduces dynamic control of the mixing process by adjusting the roll nip distance based on the specific fiber length being used. This allows the mixing conditions to be optimized for each fiber type and length, preventing excessive fiber shortening while adapting to different reinforcement requirements
2Length of moving object
If the roll nip is set equal to or above the volume average length of reinforcing fibers, then the fiber length is maintained in the mixed and cured states, but the mixing process becomes more complex and requires precise control
Solution Approach 1:
The patent applies preliminary action by calculating the volume average length of the reinforcing fibers before mixing and setting the roll nip distance accordingly in advance. This pre-planned approach simplifies the actual mixing process by eliminating the need for complex real-time adjustments, as the optimal mixing condition is determined beforehand
Solution Approach 2:
The roll nip distance acts as an intermediary parameter that mediates between the fiber length requirement and the mixing efficiency. By controlling this intermediate parameter, the patent achieves both long fiber retention and effective mixing without requiring complex direct control mechanisms
3Productivity
If conventional mixing methods are used to incorporate reinforcing fibers, then the mixing process is simple and fast, but the fiber length is significantly reduced affecting the balance between snow grip and normal road stability
Solution Approach 1:
The patent changes the mixing parameter (roll nip distance) from the conventional small gap to a larger gap equal to or greater than the fiber length. This single parameter change maintains high mixing efficiency while preserving fiber length, thereby achieving both productivity and reliability without compromise
Data Source
AI summary
A production method of a rubber composition based on an elastomer matrix, a reinforcing filler, and reinforcing fibers selected from the group consisting of basalt fibers, glass fibers, carbon fibers and the mixtures thereof, comprises at least a step of incorporating at least the reinforcing fibers into the rubber composition in a mixer provided with at least two rolls having a roll nip which is equal to or above the volume average length of reinforcing fibers before incorporating the reinforcing fibers into the rubber composition, wherein the volume average length of reinforcing fibers before incorporating the reinforcing fibers into the rubber composition is at least 1.0 mm.