Cyclic Olefin Prepolymer Viscosity Control for Defect-Free Curing
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Solution Overview
Problem
Existing methods for preparing polydicyclopentadiene (p-DCPD) thermoset materials face challenges such as low viscosity leading to surface defects, safety issues, and the need for costly additives like polymers and fillers, which affect homogeneity and transparency, while also being prone to oxidation and sedimentation.
Innovation Solution
A two-step method involving the formation of prepolymers with cyclic olefins to achieve target viscosity, followed by curing with metathesis catalysts, without the use of polymers or fillers, to produce stable and defect-free materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DCPD is heated or blended with other olefins to improve flowability, then the material becomes liquid and can be processed, but the viscosity becomes too low causing surface defects and safety issues
Solution Approach 1:
The patent applies preliminary action by pre-forming prepolymers with controlled molecular weight and viscosity before the final curing step. This preliminary polymerization creates a foundation with appropriate rheological properties that prevents subsequent viscosity problems during processing and curing, resolving the contradiction between achieving flowability and maintaining viscosity stability.
Solution Approach 2:
The patent utilizes parameter changes by controlling the molecular weight and viscosity of prepolymers through specific polymerization conditions. By adjusting parameters such as catalyst concentration, monomer-to-catalyst ratio, and reaction time, the patent achieves prepolymers with optimal viscosity that maintains both processability and reliability without requiring additional additives.
2Reliability
If rheology modifiers are added to increase viscosity, then the material achieves appropriate viscosity for processing, but the final material develops unpleasant odor and surface defects
Solution Approach 1:
The patent applies the taking out principle by eliminating the need for external rheology modifiers and fillers. Instead of adding separate additives to adjust viscosity, the patent extracts the viscosity control function into the polymerization process itself, forming prepolymers with inherent appropriate viscosity that avoids introducing harmful substances causing odor and surface defects.
Solution Approach 2:
The patent implements self-service by enabling the polymerization system to self-regulate its own viscosity through controlled prepolymer formation. The catalyst system and monomer composition work together to produce prepolymers with optimal rheological properties without requiring external rheology modifiers, thereby avoiding the harmful effects associated with additive-based approaches.
3Reliability
If fillers are added to adjust viscosity, then the material achieves desired viscosity, but the fillers sediment or aggregate affecting homogeneity
Solution Approach 1:
The patent applies taking out by removing fillers from the formulation entirely. The viscosity adjustment function is extracted from the additive package and integrated into the polymerization process itself, producing prepolymers with inherent appropriate viscosity that eliminates the homogeneity problems associated with filler sedimentation and aggregation.
Solution Approach 2:
The patent utilizes parameter changes by controlling the molecular weight distribution and viscosity of prepolymers through specific polymerization parameters. By adjusting catalyst concentration, monomer-to-catalyst ratio, and reaction conditions, the patent achieves uniform prepolymers with optimal viscosity that maintains composition stability without requiring fillers that would otherwise sediment or aggregate.
4Reliability
If chain-transfer agents are added to control polymer chain length and viscosity, then the viscosity is adjusted, but the process becomes more complex and costly
Solution Approach 1:
The patent applies universality by making the catalyst system multi-functional: it simultaneously catalyzes polymerization, controls molecular weight, and regulates viscosity. This eliminates the need for separate chain-transfer agents and simplifies the process by combining multiple functions into a single catalyst system, reducing both complexity and cost while maintaining reliable viscosity control.
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 method achieves stable viscosity for weeks or months, produces transparent and odorless materials with improved homogeneity, and avoids surface defects, while being cost-effective and safer than previous methods.
Implementation Method 1
p-DCPD is generally obtained by ring-opening metathesis of DCPD (or ROMP for 'Ring-Opening Metathesis Polymerization'), followed by crosslinking
Implementation Method 2
followed by crosslinking, leading to the following product
Data Source
AI summary
The present invention relates to a method for preparing a polymer material, comprising the successive steps of: (A) providing a prepolymer-containing monomer composition having a target viscosity, wherein said prepolymer-containing monomer composition comprises a cyclic olefin and a prepolymer of said cyclic olefin and optionally of a chain-transfer agent, (B) adding a polymerizer selected from metathesis catalysts to said prepolymer-containing monomer composition, so as to obtain a resin composition, and (C) curing said resin composition.