Endotoxin Reduction in Recovered Paper Plastic Composites
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Solution Overview
Problem
Current methods for sterilizing recovered paper and plastic materials used in building products are inadequate, as they fail to completely eliminate water-soluble endotoxins and are not cost-effective or compatible with composite manufacturing processes, leading to potential health risks and environmental concerns.
Innovation Solution
A composite material comprising thermally consolidated recovered paper and plastic fragments, treated with a multifunctional aldehyde or urea-aldehyde adduct, which cross-links endotoxins, rendering them water-insoluble, and a method for sanitizing recovered waste materials by treating them with these chemicals followed by conditioning at standard pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If current sterilization methods are used on recovered paper and plastic materials, then the manufacturing process is simple, but water-soluble endotoxins are not completely eliminated creating health risks
Solution Approach 1:
The patent changes the chemical state of endotoxins from water-soluble to water-insoluble through cross-linking reactions with multifunctional aldehydes. This parameter change (solubility) directly eliminates the health hazard while maintaining process simplicity, as the cross-linking occurs during normal composite manufacturing conditions without requiring separate sterilization equipment
Solution Approach 2:
The patent introduces multifunctional aldehydes as intermediary substances that facilitate the cross-linking of endotoxins. These aldehydes act as mediators between the endotoxins and the desired water-insoluble state, enabling the transformation through chemical reaction rather than requiring complex physical sterilization equipment
2Object-affected harmful factors
If existing sterilization methods are applied, then the process is straightforward, but endotoxins remain water-soluble causing environmental concerns
Solution Approach 1:
The patent merges the sterilization function with the existing composite manufacturing process by incorporating multifunctional aldehydes into the material mixture before consolidation. This combination eliminates the need for separate sterilization steps, maintaining ease of manufacture while achieving environmental compatibility through cross-linked, water-insoluble endotoxins
Solution Approach 2:
The patent changes the solubility parameter of endotoxins from water-soluble to water-insoluble through chemical cross-linking. This parameter change ensures environmental compatibility by preventing endotoxin leaching into water, while the cross-linking occurs under normal manufacturing conditions, preserving ease of manufacture
3Reliability
If traditional sterilization approaches are used, then the process is simple, but bacterial or fungal blooms occur when materials are exposed to water
Solution Approach 1:
The patent applies preliminary action by cross-linking endotoxins with multifunctional aldehydes before the composite material is exposed to water during manufacturing or use. This pre-treatment prevents bacterial or fungal blooms from occurring when water is introduced, as the endotoxins are already rendered water-insoluble, eliminating the need for complex post-processing conditioning
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 solution significantly reduces water-soluble endotoxin levels, ensuring the safety and environmental compatibility of the composite materials, preventing bacterial or fungal blooms when exposed to water and maintaining the integrity of the composite manufacturing process.
Implementation Method 1
treated with a multifunctional aldehyde or urea-aldehyde adduct, which cross-links endotoxins, rendering them water-insoluble
Implementation Method 2
compressing and heating a mixture comprising paper fragments or plastic fragments, or a combination thereof
Data Source
AI summary
Provided herein are composite materials comprising at least 70 wt. % thermally consolidated recovered paper and plastic fragments and less than 5,000 ng water-soluble endotoxin per gram of composite materials, as well as methods of preparing said composite materials and methods of sanitizing recovered waste materials.