Silicone Rubber Laminate Coating for Tire Bladder Sliding and Gas Release
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Solution Overview
Problem
The adhesion and sliding issues between the surface of the curing bladder and the inner liner of tires during tire curing, leading to degradation, deformation, and molding defects due to gas accumulation, are not adequately addressed by existing coatings like silicone polymers and crosslinked silicone rubber compositions.
Innovation Solution
A laminate comprising two crosslinked layers of silicone rubber compositions, one with micrometric silicone powder and one with hydrophobic silica, enhances sliding and prevents adhesion, thereby reducing bladder wear and molding defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner liner is coated with silicone polymer solution (lining cement), then adhesion between bladder and inner liner is prevented, but the operation consumes great deal of time and manpower
Solution Approach 1:
The bladder surface is pre-treated with a silane coupling agent before the curing cycle, creating a non-stick surface in advance. This eliminates the need for time-consuming manual coating operations with lining cement while ensuring reliable non-adhesion during the curing process.
Solution Approach 2:
The silane coupling agent applied to the bladder surface creates a self-lasting non-stick property that automatically prevents adhesion to the inner liner throughout the curing cycle, eliminating the need for continuous manual intervention or reapplication of coating materials.
2Reliability
If the bladder outer surface is covered with crosslinked silicone rubber composition, then adhesion is prevented, but molding defects persist due to gas accumulation
Solution Approach 1:
A porous coating layer is applied specifically to the bladder outer surface that comes into contact with the inner liner. This localized porous structure allows gas evacuation at the critical interface while maintaining non-stick properties, preventing molding defects without compromising adhesion prevention.
Solution Approach 2:
The coating layer on the bladder surface is designed with a porous structure that enables gas permeability. This allows curing gases to escape through the coating, preventing gas accumulation and molding defects, while the coating itself maintains the non-stick property needed to prevent adhesion.
3Productivity
If repeated sliding cycles occur between bladder and inner liner, then curing cycles can be completed, but deformations of casing and wear of bladder are produced
Solution Approach 1:
The porous coating layer acts as an intermediary between the bladder and the inner liner. It facilitates smooth sliding during curing cycles while preventing direct contact and adhesion, thereby reducing wear on the bladder and deformations of the casing over repeated cycles.
Solution Approach 2:
The porous structure of the coating layer reduces friction and prevents adhesion during sliding cycles. The porosity allows for smooth relative movement between the bladder and inner liner, completing curing cycles while minimizing wear and deformation through reduced mechanical stress.
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 laminate facilitates smooth sliding and prevents adhesion, reducing bladder wear and molding defects, improving tire manufacturing efficiency by extending bladder life and reducing maintenance frequency.
Implementation Method 1
The repeated sliding cycles also have the consequence of producing deformations of the casing and wear of the bladder
Implementation Method 2
the surface of the bladder and the surface of the inner liner of the tire tend to stick to one another
Implementation Method 3
A porous coating layer has been applied to the outer surface of the bladder... Any gas which may be generated during the curing cycle can escape through the porous coating layer
Data Source
AI summary
A laminate comprising a first layer and a second layer directly covering the first layer, the first layer being a layer of a silicone rubber composition comprising a micrometric silicone powder and a mixture of crosslinkable organopolysiloxanes, the second layer being a layer of a silicone rubber composition comprising a hydrophobic silica and a mixture of crosslinkable organopolysiloxanes, is provided. The first layer and the second layer are crosslinked. The laminate, in particular when it is used as a coating for the outer surface of an expandable bladder for a tire curing mold, makes it possible to eliminate molding defects on the inner liner of the tire.