Rubber Sheet Production via Steam Shock Curing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing rubber sheets and mats from rubber granules, particularly from used tires, are inefficient due to long press cycles caused by the poor thermal conductivity of rubber, making the process economically unviable.
Innovation Solution
A method involving coating rubber granules with a binder and creating an inhomogeneous moisture profile with higher moisture levels in the outer layers than the core, allowing for rapid heating and curing through the 'steam shock effect, where steam generated from the outer layers quickly heats the core, reducing pressing times and increasing cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rubber granules are pressed using conventional uniform moisture methods, then the material structure remains homogeneous, but the pressing time becomes very long due to poor thermal conductivity
Solution Approach 1:
The patent applies local quality by creating a non-uniform moisture distribution where the outer layers of the pressed material mat have higher moisture content (5-20% by weight) than the core layer (0-5% by weight). This localized moisture concentration in specific regions enables the steam shock effect to occur preferentially at the surfaces, generating steam that rapidly penetrates into the core, thereby reducing overall pressing time while maintaining homogeneous final product quality.
2Strength
If high pressure is applied to ensure proper bonding of rubber granules, then bonding strength is achieved, but the complexity of the pressing process increases
Solution Approach 1:
The patent replaces the reliance on high mechanical pressure for bonding with a chemical-thermal mechanism. By introducing the steam shock effect through localized moisture, the curing of the binder is accelerated, and bonding is achieved through the thermal and chemical action of steam-generated heat rather than purely mechanical compression. This substitution reduces the need for complex high-pressure pressing equipment and processes.
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
This approach significantly reduces production time and enhances the economic viability of rubber sheet and mat manufacturing by enabling quick curing without melting the rubber granules, optimizing heat transfer and bonding without high pressure, and allowing for continuous production.
Implementation Method 1
the water in the moist outer layers evaporates during the heating, for example upon contact with the hot press plates, thus producing steam in the outer layers
Implementation Method 2
as the result of the rapid heat transport into the core layer via the steam the core layer is also quickly heated, so that the binder likewise cures very quickly at that location. This effect, also referred to as the 'steam shock effect'
Implementation Method 3
rapid heat transport into the core layer via the steam
Implementation Method 4
with curing of the binder
Data Source
AI summary
A rubber sheet is made from rubber-containing granules by first coating the rubber granules with a binder, then forming the coated rubber granules into a mat having a core layer with a low moisture level of less than 5% and a pair of outer surface layers, and then, without substantially increasing the low moisture level in the core layer, setting in at least one of the outer layers a high moisture level of 10% to 50% by weight and thereby imparting to the mat an inhomogeneous moisture profile. The mat with the inhomogeneous moisture level is then hot-pressed with pressure and heat so as to vaporize moisture in the one outer layer and drive steam into the core layer, and the hot-pressed mat is cured.