Multilayer Rubber Barrier Structure for Bubble-Free Vulcanization
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Solution Overview
Problem
Multi-layered structures used in applications like gas-filled bladders and tires face challenges in achieving low gas transmission rates and bubble formation during the vulcanization process due to volatile compounds in rubber formulations, which affect the bonding and integrity of the layers.
Innovation Solution
A multi-layered structure comprising a core layer with a gas transmission rate of 0.05 to 0.1 cc/(m² 24 hr atm) for N₂, and a cap layer made of polydiene polyol-based polyurethane with an uncured rubber compound containing less than 5 weight percent volatile compounds, which reduces bubble formation and enhances bonding with rubber layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If uncured rubber compound with volatile compounds is used in the cap layer, then the bonding with rubber layers is enhanced, but bubble formation occurs during the vulcanization process
Solution Approach 1:
The patent removes volatile compounds from the uncured rubber compound formulation used in the cap layer. By extracting these harmful volatile substances before the vulcanization process, the invention prevents bubble formation at the layer interfaces while maintaining the bonding capabilities of the rubber compound.
Solution Approach 2:
The patent changes the chemical composition parameters of the uncured rubber compound by limiting volatile compounds to less than 5 weight percent. This parameter modification allows the rubber to bond effectively with other layers during vulcanization without generating bubbles, thus resolving the contradiction between bonding strength and bubble formation.
2Ease of manufacture
If conventional rubber formulations are used in the cap layer, then ease of manufacture is maintained, but gas transmission rate increases
Solution Approach 1:
The patent creates a composite cap layer structure combining uncured rubber compound (with less than 5 wt% volatile compounds) and polydiene polyol-based polyurethane. This composite formulation provides both the manufacturability of conventional rubber and the superior gas barrier properties needed to achieve low gas transmission rates.
Solution Approach 2:
The invention applies different material properties to different layers of the multi-layered structure. The cap layer uses a specialized low-volatile rubber compound optimized for bonding and bubble prevention, while the core layer uses materials optimized for gas barrier performance, creating local quality optimization throughout the structure.
3Reliability
If multiple layers are bonded together to improve gas barrier properties, then gas transmission rate decreases, but bonding integrity is compromised by bubble formation
Solution Approach 1:
By removing volatile compounds from the cap layer rubber compound before vulcanization, the invention eliminates the source of bubbles that would compromise layer bonding integrity. This allows multiple layers to be bonded together with full integrity while maintaining the gas barrier performance benefits of the multi-layered structure.
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 solution effectively reduces bubble formation at the interface between layers, improving the bonding and integrity of the multi-layered structure, resulting in superior performance and resistance to fatigue failure with enhanced gas barrier properties.
Implementation Method 1
The first cap layer includes one or more polydiene polyol-based polyurethane... enhance the performance of the multi-layered structure by improved bonding with the core and/or a rubber disposed on the cap layer
Implementation Method 2
The uncured rubber compound includes less than 5 weight percent of volatile compounds, where the volatile compounds are volatile compounds released from the uncured rubber compound when the uncured rubber compound is heated to a temperature of about 200 degrees Celsius
Implementation Method 3
The core layer has a gas transmission rate of 0.05 to 0.1 cc/(m² 24 hr atm) for N₂
Data Source
Figure 1~3
Figure 4A~5
Figure 6A~6B
AI summary
Multi-layered structures including a core and at least one cap layer adjacent one another, wherein the cap layer includes one or more polydiene polyol-based polyurethane and uncured rubber; and multilayer articles comprising a core, at least one cap layer comprising a cured rubber, and a rubber layer bonded to the cap layer.