Silicone Rubber Membrane Coating for Tire Curing Gas Venting
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Solution Overview
Problem
The traditional curing membranes for tire manufacturing stick to the inner rubber surface of tires due to similar chemical compositions, leading to membrane wear, casing deformation, and molding defects from gas accumulation, necessitating a labor-intensive non-stick treatment.
Innovation Solution
A laminate structure comprising a diene rubber layer and a silicone rubber layer with micrometric silicone powder and crosslinkable organopolysiloxanes, which prevents sticking and facilitates sliding while venting gases, eliminating defects and extending membrane life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the curing membrane surface is covered with a cross-linked silicone rubber composition, then non-stick properties are improved, but molding defects persist due to gas accumulation
Solution Approach 1:
The patent applies a silicone rubber composition containing microparticles (average diameter 1-100 μm) that creates a porous surface structure on the curing membrane. This porous structure allows gases to escape through the membrane surface during curing, preventing gas accumulation and the resulting molding defects while maintaining the non-stick properties of the silicone rubber coating.
Solution Approach 2:
The patent uses a composite silicone rubber composition combining cross-linked silicone rubber with microparticles. This composite material provides both the non-stick characteristics of silicone rubber and the gas venting capability of the microparticle structure, simultaneously addressing both the sticking problem and the molding defect issue.
2Reliability
If the inner rubber is coated with non-stick solution (lining cement), then sticking is prevented, but the process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent makes the curing membrane self-sufficient by incorporating the non-stick functionality directly into the membrane structure through the silicone rubber composition with microparticles. This eliminates the need for separate manual coating operations with lining cement, allowing the membrane to provide non-stick properties inherently without requiring additional labor-intensive treatment steps.
Solution Approach 2:
The patent merges the non-stick function (previously provided by separate lining cement coating) with the membrane structure itself by using a silicone rubber composition containing microparticles. This consolidation integrates multiple functions into a single component, eliminating the need for separate coating operations and improving productivity.
3Productivity
If repeated deployment and retraction cycles are performed, then productivity is improved, but slippage causes casing deformation and membrane wear
Solution Approach 1:
The microparticle-containing silicone rubber composition creates a porous surface structure that reduces friction and slippage between the membrane and the tire casing during deployment and retraction cycles. This porous structure allows for smoother relative motion, reducing wear on both the membrane and the casing, thereby maintaining membrane durability even with repeated cycling.
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 structure reduces membrane wear, casing deformation, and molding defects, enhancing productivity by allowing multiple curing cycles without manual non-stick treatments.
Implementation Method 1
a laminate structure comprising a diene rubber layer and a silicone rubber layer with micrometric silicone powder and crosslinkable organopolysiloxanes, which prevents sticking and facilitates sliding
Implementation Method 2
The tire curing process releases gases such as water vapor into the curing mold, particularly between the outer surface of the membrane and the inner rubber layer. An accumulation of these gases trapped between the outer membrane and the inner rubber can cause localized overheating or overpressure
Data Source
AI summary
The invention relates to a silicone rubber composition comprising a silicone micro-powder and a mixture of crosslinkable organopolysiloxanes. Said composition is used as a coating for the outer surface of an expandable membrane for a pneumatic tire curing mold and makes is possible to prevent molding defects on the inner liner of the tire.