Polyester Viscosity Modifier Composition to Prevent Gel Formation
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Solution Overview
Problem
Existing condensation polymers face challenges in maintaining consistent melt viscosity and preventing gel formation during recycling and reuse, with current chain extenders posing handling issues, toxicity concerns, and equipment investment requirements.
Innovation Solution
A viscosity modifier comprising a chain extender derived from a reactive monomer and vinyl monomer reaction, combined with a non-condensation carrier resin, is used to enhance melt viscosity and prevent bridging, with specific weight percentages and refractive index matching to ensure compatibility and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If phosphite-based chain extenders are used to increase melt viscosity, then melt viscosity is improved, but handling difficulty increases and toxicity concerns arise
Solution Approach 1:
The patent uses isocyanate-based chain extenders which are consumed during the polycondensation reaction to extend polymer chains. These chain extenders are used in controlled amounts (0.1-5 wt%) and fully react during processing, eliminating the need for recovery or causing minimal residual effects, thus resolving the handling and toxicity issues of persistent additives
Solution Approach 2:
The patent changes the chemical parameters of the chain extender by selecting isocyanate-based compounds with specific molecular weights (500-5000 g/mol) and reactive functionalities. This parameter optimization enables effective melt viscosity enhancement while controlling reactivity and minimizing handling difficulties through proper selection of physical and chemical properties
2Quantity of substance
If isocyanate-based chain extenders are used to increase melt viscosity, then melt viscosity is improved, but toxicity and reactivity to moisture increase
Solution Approach 1:
The isocyanate-based chain extenders are designed to be fully consumed during the polycondensation reaction, reacting with hydroxyl groups to form urethane linkages. This complete reaction eliminates residual toxic substances and minimizes moisture reactivity issues, as the reactive isocyanate groups are converted to stable urethane structures during processing
Solution Approach 2:
The patent converts the potential harm of moisture reactivity into a benefit by utilizing the reaction between isocyanate groups and moisture to trigger controlled chain extension. The moisture reactivity is harnessed to initiate the viscosity-enhancing reaction while the resulting urethane formations provide stable, non-toxic final structures
3Quantity of substance
If repetitive polycondensation is used to increase melt viscosity, then melt viscosity is improved, but equipment investment and processing time increase
Solution Approach 1:
The patent applies preliminary action by adding the chain extender to the polymerization system before the main polycondensation reaction occurs. The chain extender is introduced in controlled amounts (0.1-5 wt%) and reacts during the extrusion or molding process, eliminating the need for separate repetitive polycondensation equipment and reducing processing time while achieving the desired melt viscosity enhancement
4Quantity of substance
If chain extenders are used to increase melt viscosity, then melt viscosity is improved, but gel formation and bridging occur
Solution Approach 1:
The patent optimizes parameters including chain extender molecular weight (500-5000 g/mol), concentration (0.1-5 wt%), and reaction temperature to achieve the desired melt viscosity enhancement while preventing gel formation. The controlled parameter selection ensures uniform chain extension without creating cross-linked gel structures or bridging issues during processing
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 provides improved melt viscosity and prevents gel formation, ensuring consistent processing and transparency in molded articles, while avoiding handling difficulties and reducing equipment costs.
Implementation Method 1
a chain extender obtained from a reaction between at least one reactive monomer and at least one vinyl monomer copolymerizable with the reactive monomer
Implementation Method 2
the chain extender comprising at least one reactive group and being present in an amount ranging from 50 to 90 wt % of the viscosity modifier
Data Source
AI summary
A viscosity modifier for a condensation polymer may include a chain extender obtained from a reaction between at least one reactive monomer and at least one vinyl monomer copolymerizable with the reactive monomer, the chain extender comprising at least one reactive group and being present in an amount ranging from 50 to 90 wt % of the viscosity modifier; and a non-condensation carrier resin comprising from greater than 2.5 wt % to 10 wt % of units derived from a reactive monomer in the carrier resin, the non-condensation carrier resin present in an amount ranging from 10 to 50 wt % of the viscosity modifier. Condensation polymer compositions, methods of forming viscosity modifiers, and methods of molding condensation polymer compositions are also provided.