Compostable Biopolymer Case with Rigid Back and Soft Bumper
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Solution Overview
Problem
Existing electronic device cases are not made entirely from compostable biopolymer materials, as clear biopolymer resins are brittle and unable to provide adequate protection, leading to the use of conventional plastics for clear cases.
Innovation Solution
A protective case made from 100% compostable biopolymers, featuring a clear, rigid back surface and a softer, opaque bumper made from elastomeric bioplastics, with the back surface over-molded into the bumper to provide both transparency and protection, using injection molding and over-molding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If clear biopolymer resins are used for the case, then transparency is achieved, but the material becomes brittle and cannot provide adequate protection
Solution Approach 1:
The patent applies composite materials by combining two different biopolymer materials with distinct properties: a clear rigid biopolymer for the back surface providing transparency and structural support, and a softer opaque biopolymer for the bumper providing protection. This composite structure resolves the contradiction by allowing each material to fulfill its specific function - the rigid clear portion maintains transparency while the softer portion provides impact protection.
Solution Approach 2:
The patent implements local quality by assigning different material properties to different regions of the case. The back surface uses a clear rigid biopolymer optimized for transparency and structural integrity, while the bumper uses a softer opaque biopolymer optimized for shock absorption and protection. This spatial differentiation of material properties allows the case to simultaneously achieve transparency where needed and protection where required.
2Strength
If conventional plastics are used for clear cases, then protection capability is achieved, but compostability is lost
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and physical properties of biopolymer materials to achieve the desired balance between protection and compostability. Specifically, the elastomeric biopolymer used in the bumper has tailored parameters including elongation at break of 50-150%, tensile strength of 5-15 MPa, and hardness of 40-60 Shore A, which provide adequate protection while maintaining compostability. This resolves the contradiction by showing that compostable materials can be engineered to meet protection requirements through parameter optimization.
3Stability of the object's composition
If a single rigid material is used for the case, then structural integrity is achieved, but flexibility and impact absorption are reduced
Solution Approach 1:
The patent applies segmentation by dividing the case into two distinct functional segments: a rigid clear back surface made from clear rigid biopolymer for structural integrity, and a flexible opaque bumper made from elastomeric biopolymer for impact absorption. The bumper specifically provides flexibility with its elastomeric properties (elongation at break of 50-150%), while the rigid back surface maintains structural integrity. This segmentation resolves the contradiction by distributing different mechanical requirements to different segments of the case.
Data Source
AI summary
In one embodiment there is provided a protective case for an electronic device. The case has a substantially transparent planar back surface. The substantially transparent planar back surface is made from a compostable biopolymer material configured to form a rigid back surface and wherein the substantially transparent planar back surface has a terminal outer periphery edge. An outer bumper formed into a continuous side wall extends transversely from the planar back surface. The continuous side wall has an inwardly extending edge such that the outer bumper is configured to form fit around an electronic device. The outer bumper is made from a compostable biopolymer material configured to form into the outer bumper that is softer then the rigid back surface, and wherein the outer periphery edge of the transparent planar back surface is over-molded into the outer bumper.