Aliphatic Polyurethane Pebble Surfacing for UV Stability
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Solution Overview
Problem
Existing surfacing materials lack improved UV light stability, chemical resistance, and safety performance, particularly in varying environmental conditions, and often suffer from outgassing issues during curing.
Innovation Solution
The use of aliphatic thermoplastic polyurethane pebbles bonded with two-part polyurethane binders, which include specific polyols and isocyanates, to create either porous or non-porous surfaces, and their application in a multi-layer safety surface with a buffer layer to manage thermal expansion and provide enhanced fall protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional surfacing materials are used, then they can be applied to provide enhanced features, but they lack improved UV light stability and chemical resistance
Solution Approach 1:
The patent uses composite materials by combining aliphatic thermoplastic polyurethane pebbles with two-part polyurethane binders containing specific polyols and isocyanates. This composite structure provides both improved UV light stability through the aliphatic polyurethane components and enhanced chemical resistance through the cross-linked binder system, resolving the contradiction between these two durability requirements.
Solution Approach 2:
The patent changes the chemical parameters of the binder system by using specific ratios of polyols to isocyanates and selecting particular chemical compositions (esterified ricinoleic acid polyols, caprolactone polyols, hydrogenated methylene diphenyldisocyanate, hexamethylene diisocyanate). These parameter changes optimize both UV stability and chemical resistance simultaneously, addressing the contradiction between these two performance characteristics.
2Ease of manufacture
If traditional surfacing materials are used, then they can provide basic surface enhancement, but they suffer from outgassing issues during curing
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by selecting specific polyol and isocyanate combinations that minimize outgassing during curing. The use of esterified ricinoleic acid polyols and caprolactone polyols in controlled ratios with hydrogenated methylene diphenyldisocyanate and hexamethylene diisocyanate reduces harmful gas evolution while maintaining ease of manufacture and proper curing characteristics.
3Reliability
If pebbles are bonded with two-part binders, then UV light stability and chemical resistance are improved, but the surface may become porous due to outgassing
Solution Approach 1:
The patent optimizes the stoichiometric ratio and chemical composition parameters of the two-part binder system to control the curing reaction and minimize outgassing. By carefully selecting the polyol to isocyanate ratio and using specific chemical compositions, the patent achieves both improved UV light stability and maintains surface composition stability with reduced porosity.
Solution Approach 2:
The patent uses a composite binder system combining multiple polyols and isocyanates that work synergistically to provide both UV stability and controlled porosity. The aliphatic polyurethane pebbles combined with the specific two-part binder create a composite material that resists UV degradation while the controlled chemistry minimizes outgassing-induced porosity.
4Reliability
If a multi-layer safety surface is used, then fall protection and thermal expansion management are improved, but the device complexity increases
Solution Approach 1:
The patent segments the safety surface into distinct functional layers: a pebble-based wear layer for UV stability and chemical resistance, a buffer layer for thermal expansion management, and a cushion layer for fall protection. This segmentation allows each layer to be optimized for its specific function while collectively providing comprehensive safety performance.
Solution Approach 2:
The multi-layer structure provides multiple functions within a single integrated system: the wear layer provides UV and chemical resistance, the buffer layer manages thermal expansion, and the cushion layer provides fall protection. This multi-functionality approach justifies the increased complexity by delivering comprehensive safety performance that a single-layer system cannot achieve.
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 provides improved UV light stability, chemical resistance, longer lifetime, reduced outgassing, and enhanced safety performance across a range of temperatures and humidities, with the ability to create both porous and non-porous surfaces as needed, suitable for various applications such as playgrounds and pools.
Implementation Method 1
pebbles comprised of aliphatic thermoplastic polyurethane pebbles are bonded together with an A side of the two-part binder that has at least one polyol, and a B side of the two-part binder that has multiple isocyanates
Implementation Method 2
When the A side of the two-part binder is combined with a B side of the two-part binder, the multiple polyol mixture may result in little or no outgassing
Implementation Method 3
The buffer layer can be used to compensate for differences in the coefficients of thermal expansion for the wear layer and the cushion layer
Data Source
AI summary
Pebble or granular based elastomeric surfacing materials that include an aliphatic thermoplastic polyurethane based pebble or granule bonded together with a two-part aliphatic polyurethane binder are provided. In one embodiment, an A side of the two-part binder has at least one polyol, and a B side of the two-part binder has multiple isocyanates. The multiple isocyanates can include for example hydrogenated methylene diphenyldisocyanate and hexamethylene diisocyanate. The A side and the B side of the binder are utilized to bond the pebbles together to form a surface that can be either porous or non-porous. In another embodiment, an A side of a two-part binder includes multiple polyols. The multiple polyols can include for example esterified ricinoleic acid polyols and caprolactone polyols. The A side of the two-part binder can be combined with a B side of the two-part binder and pebbles to form a non-porous surface. In yet another embodiment, a pebble-based surface is utilized as a wear layer in a multi-layer safety surface.