Polyolefin Foamed Sheet Cell Rupture via Differential Roll Shear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing crosslinked polyolefin foamed sheets face inefficiencies in production due to complex crosslinking/foaming steps and result in materials with hard non-foamed layers, lacking flexibility and having poor vacuum moldability.
Innovation Solution
A method involving the use of rolls with different circumferential speeds to apply compression and shear stress to foamed sheets with closed cells, converting them into open cells, while maintaining a crosslinked structure through electron beam or chemical crosslinking, to enhance heat resistance, flexibility, and vacuum moldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex crosslinking/foaming steps are used to produce crosslinked polyolefin foamed sheets, then the material achieves crosslinked structure and foam formation, but production efficiency deteriorates
Solution Approach 1:
The patent applies preliminary crosslinking to the polyolefin resin before the foaming step. By pre-crosslinking the resin to form a crosslinked foamable composition, the subsequent foaming process becomes more efficient and controlled, resolving the contradiction between achieving reliable crosslinked structure and maintaining high production efficiency.
2Ease of operation
If mechanical deformation is applied to communicate cells in crosslinked polyolefin open cell body, then open cells are formed, but the non-foamed layer on the surface becomes hard and lacks flexibility
Solution Approach 1:
The patent applies local quality by subjecting only the inner layer of the foamed sheet to mechanical deformation between rolls, while the outer skin layer remains substantially intact. This selective deformation communicates cells in the inner layer to provide flexibility, while preserving the skin layer's integrity to maintain surface properties.
3Adaptability or versatility
If closed cells are converted to open cells through compression and shear stress, then flexibility and vacuum moldability improve, but cell structure integrity may deteriorate
Solution Approach 1:
The patent applies partial action by using moderate compression and shear stress that is sufficient to communicate a portion of the closed cells in the inner layer, rather than completely collapsing all cells. This partial deformation achieves improved flexibility and vacuum moldability while maintaining adequate cell structure integrity for structural support.
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 resulting polyolefin-based resin crosslinked foamed sheets exhibit improved heat resistance, flexibility, and vacuum moldability, with a balanced compressive strength and repulsion force, suitable for various applications including sealing and automotive interior materials.
Implementation Method 1
applying a compression force and a shear stress to the foamed sheet with closed cells to rupture a part of closed cells
Implementation Method 2
applying a compression force and a shear stress to the foamed sheet with closed cells to rupture a part of closed cells
Implementation Method 3
a foamed sheet with closed cells having a crosslinked structure obtained by electron beam crosslinking
Data Source
AI summary
The present invention provides a method for producing a polyolefin-based resin crosslinked foamed sheet which is excellent in heat resistance and flexibility, has a small diameter of cells, can be developed in various utilities, and is excellent in vacuum moldability. The method for producing a polyolefin-based resin crosslinked foamed sheet according to the present invention comprises the steps of supplying a foamed sheet with closed cells, comprising a polyolefin-based resin, to a gap between one pair of rolls which have different circumferential speeds, and are rotated so that rotation directions on facing surfaces are the same direction, and applying a compression force and a shear stress to the foamed sheet with closed cells simultaneously to rupture a part of closed cells of the foamed sheet with closed cells to communicate closed cells into open cells.