Recycled PET Bottle Sidewall Ribs for Steam Sterilization Stability
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Solution Overview
Problem
Recycled PET bottles exhibit unpredictable physical stability and deformation during steam sterilization due to temperature-induced changes in modulus, making them unsuitable for steam sterilization processes, especially when compared to HDPE and other polymers.
Innovation Solution
A bottle design featuring a sidewall with annular ribs and recessed lands, manufactured using a blow molding process with recycled PET, which provides dimensional stability of less than 1% change during steam sterilization, and a structural configuration that resists deformation at temperatures between 75-85°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steam sterilization process is used to sterilize bottles, then bacteria kill rate is improved, but bottle deformation and shrinkage occur due to temperature-induced modulus changes
Solution Approach 1:
The patent modifies the physical-chemical parameters of PET by incorporating recycled content and adjusting processing conditions to achieve a material that maintains dimensional stability at sterilization temperatures (75-85°C) while remaining sterilizable
Solution Approach 2:
The patent applies different structural characteristics to different parts of the bottle, particularly using reinforced rib structures in critical areas to prevent deformation while allowing the rest of the bottle to maintain its intended form
2Ease of manufacture
If recycled PET is used to manufacture bottles, then material cost and sustainability are improved, but physical stability and dimensional consistency deteriorate due to intrinsic viscosity variation
Solution Approach 1:
The patent specifies controlled parameter ranges for recycled PET including intrinsic viscosity (0.60-0.80 dL/g) and residual monomer content (<50 ppm) to ensure consistent physical properties and dimensional stability while maintaining cost-effectiveness
Solution Approach 2:
The patent creates a composite structure by combining recycled PET with specific structural features (ribs, flutes, thickness variations) to compensate for material variability and achieve consistent dimensional performance
3Volume of moving object
If square or non-cylindrical bottle shapes are used, then packaging efficiency is improved, but deformation control becomes more difficult during sterilization
Solution Approach 1:
The patent applies localized structural reinforcements (ribs, flutes, thickness variations) to specific areas of square bottles to prevent deformation at critical locations while maintaining the overall square geometry for packaging efficiency
Solution Approach 2:
The patent incorporates curved elements (rounded corners, flutes, rib profiles) into square bottle designs to reduce stress concentration and improve deformation resistance during sterilization while preserving the square cross-section for packaging
Data Source
AI summary
A bottle includes a neck portion having an opening configured to permit filling and emptying of the bottle, a shoulder portion connected to a lower end of the neck portion, a sidewall connected to a lower end of the shoulder portion and extending vertically downward from the shoulder portion, and a base connected to a lower end of the sidewall and forming a bottom surface of the bottle. The sidewall has a plurality of annular ribs extending around a periphery of the sidewall. Each of the annular ribs includes a plurality of sequential enlarged portions interconnected by bridges, with each of the enlarged portions having a vertical width that is greater than a vertical width of each of the bridges.