Polyester Surface Modification for Paper Recycling
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Solution Overview
Problem
Existing polyesters used in paper recycling processes have unsatisfactory results in modifying hydrophobic surfaces to reduce deposits of undesirable bonding residues, and they often rely on potentially toxic catalysts like antimony trioxide.
Innovation Solution
Polyesters are synthesized by polymerizing dimethyl terephthalate, ethylene glycol, 1,2-propylene glycol, and polyethylene glycol with specific molecular weight ranges, either in the presence or absence of crosslinking compounds, without using Sb2O3 as a catalyst, resulting in polyesters with improved molecular weight distribution and reduced toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyesters are used in paper recycling processes, then adhesive deposits can be reduced to some extent, but the results are unsatisfactory and toxicological concerns arise from catalyst usage
Solution Approach 1:
The patent specifies precise molecular weight ranges for polyethylene glycol (1000-2000 g/mol) and methyl polyethylene glycol (1050-1350 g/mol) to optimize the polyester's effectiveness in reducing adhesive deposits while avoiding toxicity. This parameter optimization resolves the contradiction by achieving reliable performance without harmful catalysts
Solution Approach 2:
The patent eliminates the need for persistent toxic catalysts like antimony trioxide by using alternative catalyst systems that do not leave harmful residues. This approach replaces harmful long-lasting catalysts with safer alternatives, reducing toxicological concerns while maintaining effectiveness
2Reliability
If polyethylene glycol with high molecular weight is used, then the polyester achieves better surface modification properties, but the synthesis becomes more complex and costly
Solution Approach 1:
The patent optimizes the molecular weight parameters of polyethylene glycol (1000-2000 g/mol) and methyl polyethylene glycol (1050-1350 g/mol) to achieve the desired surface modification properties. This parameter optimization balances performance requirements with synthesis feasibility, avoiding excessive complexity while maintaining effectiveness
3Ease of manufacture
If conventional polyester synthesis methods are used, then production is simpler, but residual low molecular weight monomers remain causing toxicological issues
Solution Approach 1:
The patent specifies precise molecular weight ranges for the polyethylene glycol and methyl polyethylene glycol components to ensure complete polymerization and eliminate residual low molecular weight monomers. This parameter control maintains synthesis simplicity while preventing toxicological issues through thorough polymerization
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 synthesized polyesters effectively increase the surface tension of hydrophobic surfaces, significantly reducing adhesive deposits in paper recycling processes, while being environmentally and toxicologically safer due to the absence of residual monomers with low molecular weights and the use of non-carcinogenic catalysts.
Implementation Method 1
The polyesters according to the invention are advantageously suitable for modifying hydrophobic surfaces, in particular for increasing their surface tension and thus reducing the affinity of the modified surfaces for hydrophobic substances
Implementation Method 2
The polyesters according to the invention have a high affinity for hydrophobic surfaces and cause hydrophobic surfaces to become more hydrophilic and thus their wettability is improved
Data Source
AI summary
The present invention relates to polyester that can be obtained by polymerization of a) terephtalacid dimethylester, and b) ethylene glycol, and c) 1,2-propylene glycol, and d) one or a plurality of polyethylene glycols having weight average molecular weights in the range of 1,000 to 2,000 g/mol, and e) one methyl polyethylene glycol having a weight average molecular weight in the range of 1,050 to 1,350 g/mol, f) either when a plurality of compounds having a reticulating effect and 3 to 6 functions that are enabled for polycondensation are present or absent. The polyester according to the invention can be used in an advantageous manner, e.g. to modify hydrophobic surfaces, which can be used, e.g., in paper recycling.