3D Polyethylene Net Structure for Smooth Bending Without Wrinkles
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Solution Overview
Problem
Three-dimensional net-like structures made from high surface density materials like polyethylene experience unnatural deformation and wrinkles when bent, making them difficult to shape according to care beds or sofa beds, and there is a need for lighter, more durable materials to alleviate the load on caregivers.
Innovation Solution
A three-dimensional net-like structure made from polyethylene with a specific swelling ratio dependent on shear rate, featuring a curled spring structure and a three-dimensional striped sparse-dense configuration, with a filament diameter of 0.2 to 1.3 mm and bulk density of 0.01 to 0.2 g/cm3, allowing for enhanced flexibility and smooth bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethylene with high surface density is used to make three-dimensional net-like structure, then durability is improved, but the structure becomes difficult to bend smoothly and develops wrinkles
Solution Approach 1:
The patent applies parameter changes by precisely controlling the swelling ratio of polyethylene at different shear rates (0.93-1.16 at 24.3 sec⁻¹, 1.00-1.20 at 60.8 sec⁻¹, 1.06-1.23 at 121.6 sec⁻¹, 1.11-1.30 at 243.2 sec⁻¹, 1.15-1.34 at 608.0 sec⁻¹, and 1.16-1.38 at 1216 sec⁻¹) and controlling bulk density (0.01 to 0.2 g/cm³). This enables the material to achieve both durability and smooth bendability without wrinkles by optimizing the molecular structure and physical properties of polyethylene.
2Reliability
If polyethylene material is used for mattress, then durability is improved, but weight is increased causing higher load on caregivers
Solution Approach 1:
The patent resolves this contradiction by changing the density parameter of polyethylene to 0.82 to 0.95 g/cm³ and controlling the bulk density of the three-dimensional net-like structure to 0.01 to 0.2 g/cm³. This creates a lightweight yet durable material that reduces mattress weight for easier handling by caregivers while maintaining structural integrity and durability.
3Strength
If three-dimensional net-like structure is made with high bulk density, then structural strength is improved, but flexibility and bendability are reduced
Solution Approach 1:
The patent applies parameter changes by establishing an optimal bulk density range of 0.01 to 0.2 g/cm³, which balances structural strength and flexibility. This parameter optimization allows the three-dimensional net-like structure to maintain adequate structural strength while achieving the flexibility needed for smooth bending applications in care beds and sofa beds.
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 structure achieves adequate flexibility and bendability, reducing wrinkles and improving usability, while maintaining durability and light weight, thus addressing the challenges of deformation and caregiver load.
Implementation Method 1
the swelling ratio is shown as D2/D1 against shear rate when the polyethylene in molten state is extruded to the filaments from a capillary having a tube inner diameter D1 of 1.0 mm and a length of 10 mm at a temperature of 190° C.
Implementation Method 2
D2 denotes a diameter of cross section of the polyethylene filaments extruded and cooled down
Data Source
AI summary
By taking into account the difficulty in smoothly bending along the shape of, for example, a care bed, there is provided a three-dimensional net-like structure made from polyethylene having a swelling ratio dependent on a shear rate such as to be 0.93 to 1.16 at a shear rate of 24.3 sec−1 and 1.15 to 1.34 at a shear rate of 608 sec−1 and having an MFR of 3 to 35 g/10 min and a density of 0.82 to 0.95 g/cm3 and configured to have a spring structure of filaments randomly brought into contact with and tangled with one another, have a three-dimensional striped sparse-dense configuration in a lateral direction relative to an extrusion direction. The swelling ratio is shown as D2/D1 against shear rate when a molten thermoplastic resin is extruded to filaments from a capillary having a tube inner diameter D1 of 1.0 mm and a length of 10 mm and D2 denotes a diameter of cross section of the filaments extruded and cooled down.