Water-Repellent EPS Products With Dense Surface Layers
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Solution Overview
Problem
Existing EPS products lack waterproof properties, which can lead to moisture penetration, especially in applications like refrigerator evaporator covers where moisture can accumulate and cause issues.
Innovation Solution
A two-layer EPS structure is created, with a denser polystyrene layer on top of a less dense EPS body, formed simultaneously in a mold using a heating core and resin replenishment device to ensure the polystyrene layer has higher density and thickness, preventing moisture penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer EPS structure is used, then the manufacturing process is simple, but the product lacks waterproof properties and allows moisture penetration
Solution Approach 1:
The EPS product is divided into two distinct layers: a lower-density EPS body layer for insulation and a higher-density polystyrene surface layer for waterproofing. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between simplicity and waterproof performance.
Solution Approach 2:
The invention uses a composite structure combining two different densities of polystyrene foam materials. The EPS body provides thermal insulation while the denser polystyrene surface layer provides waterproofing, creating a composite material system that achieves both insulation and moisture resistance.
2Reliability
If a denser polystyrene layer is formed on the EPS body, then waterproofing is improved, but the manufacturing process becomes more complex requiring heating cores and resin replenishment
Solution Approach 1:
The heating core is pre-positioned in the mold before casting, and the resin replenishment passages are pre-formed in the mold structure. This preliminary preparation enables the automatic formation of the dense polystyrene surface layer during the casting process itself, without requiring complex post-processing steps.
Solution Approach 2:
The heating core acts as an intermediary tool that transfers thermal energy to the resin, causing localized densification of the polystyrene at the surface. This intermediary mechanism enables controlled density variation without requiring complex direct manipulation of the material during manufacturing.
3Reliability
If the polystyrene layer is made thicker to improve waterproofing, then moisture resistance increases, but the overall product dimensions and weight increase
Solution Approach 1:
The dense polystyrene layer is applied locally only at the surface where waterproofing is needed, rather than increasing the thickness of the entire EPS product. This local quality enhancement provides effective moisture resistance while maintaining the lightweight characteristics of the overall structure.
Solution Approach 2:
The invention changes the density parameter of the polystyrene material at the surface layer rather than increasing the thickness parameter. By creating a thin layer with higher density (greater than 0.05 g/cm³), the product achieves waterproofing without significant weight increase.
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 EPS product achieves effective waterproofing, minimizing moisture ingress and maintaining performance in humid environments, particularly in refrigerator components.
Implementation Method 1
a heating core provided in the upper core and configured to form a polystyrene layer on the EPS product
Implementation Method 2
a steam generator configured to supply steam heating the upper core and the lower core
Implementation Method 3
a cooling device configured to cool the upper core and the lower core
Data Source
AI summary
An expanded polystyrene (EPS) product includes an EPS body; and a polystyrene layer on a portion of a surface of the EPS body, wherein a density of the polystyrene layer is greater than a density of the EPS body, and both the EPS body and the polystyrene layer include EPS.