Polyester 3D 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 are difficult to bend smoothly due to unnatural deformation and wrinkles, posing challenges in applications such as care beds and sofa beds, where a lighter and more durable mattress is required.
Innovation Solution
A three-dimensional net-like structure made from polyester with a specific swelling ratio and density, featuring a curled spring structure and a three-dimensional striped sparse-dense configuration, allowing for enhanced flexibility and smooth bending without noise, achieved through a polyester block copolymer with a high melting-point crystalline polymer segment and a low melting-point polymer segment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethylene material with high surface density is used, then durability is improved, but bendability deteriorates causing wrinkles and folds
Solution Approach 1:
The patent changes the material parameter from polyethylene to polyester and controls the swelling ratio within 1.00 to 1.60 at specific shear rates. This parameter change enables the material to achieve both high durability and smooth bendability without wrinkles, resolving the contradiction between durability and ease of bending operation.
Solution Approach 2:
The patent uses polyester block copolymer composed of high melting-point crystalline polymer segment and low melting-point polymer segment. This composite material structure provides both the durability needed for medical applications and the flexibility required for smooth bending without deformation.
2Stability of the object's composition
If polyethylene material is used, then structural stability is improved, but texture naturalness deteriorates with unnatural deformation
Solution Approach 1:
The patent changes the material from polyethylene to polyester and precisely controls the swelling ratio parameter within 1.00 to 1.60. This maintains structural stability while preventing unnatural texture deformation and wrinkles during bending, preserving the natural appearance of the mattress surface.
3Strength
If high surface density material is used, then strength is improved, but weight increases causing load on nurses
Solution Approach 1:
The patent employs polyester block copolymer with specific composition ratios of high and low melting-point segments. This composite material achieves the required strength for medical mattress applications while maintaining a weight that is easier for nurses to handle compared to traditional high-density polyethylene materials.
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 is adequately flexible and bendable, maintains a soft texture, and has improved heat-resistant properties, allowing for easy washing and drying, while reducing the load on caregivers and improving durability.
Implementation Method 1
the swelling ratio is shown as D2/D1 against shear rate when the polyester 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 210° C.
Implementation Method 2
The polyester is a polyester block copolymer (A) having a high melting-point crystalline polymer segment (a) mainly comprised of a crystalline aromatic polyester unit and a low melting-point polymer segment (b) mainly comprised of an aliphatic polyether unit and/or an aliphatic polyester unit as main components.
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 polyester having a swelling ratio dependent on a shear rate such as to be 1.10 to 1.38 at a shear rate of 60.8 sec−1 and 1.17 to 1.43 at a shear rate of 608 sec−1 and having an MFR of 3 to 35 g/10 min and a density of 1.01 to 1.60 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.