Polymer Polyol Preparation via Seed Polymerization with Heel
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Solution Overview
Problem
Existing methods for producing polymer polyols struggle to achieve a balance between high solid content and low viscosity, which is essential for efficient handling and optimal properties in flexible polyurethane foams, often requiring complex combinations of continuous and semi-batch operations.
Innovation Solution
A batch or semi-batch process involving the use of a seed polymerized in a base polyol with a polymer polyol heel, along with additional ethylenically unsaturated monomers and a macromer, to achieve a broad particle size distribution and low viscosity at high solids content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high solid polymer content is achieved in polymer polyol, then the polymer content increases, but the viscosity increases making handling difficult
Solution Approach 1:
The patent changes the particle size distribution parameters of the polymer to achieve a broad distribution with specific mean particle sizes (0.1-10 micrometers). This parameter change allows high solid content while maintaining low viscosity because the broad distribution prevents excessive chain entanglement that would occur with narrow distributions at high concentrations.
Solution Approach 2:
The patent creates a composite polymer polyol system combining polymer particles dispersed in a polyol base. The composite structure consists of solid polymer particles (0.1-10 micrometers) distributed within a liquid polyol matrix, achieving both high solid content and low viscosity through the specific composite architecture.
2Stability of the object's composition
If narrow particle size distribution is used, then the polymer polyol has uniform properties, but the cell opening is limited and crushing force increases
Solution Approach 1:
Instead of using a narrow particle size distribution (conventional approach), the patent inverts the approach by using a broad particle size distribution. This inversion leads to improved cell opening and reduced crushing force, as the broader distribution allows for better foam cell formation and weaker cell walls that crush more easily.
3Productivity
If continuous process is used for polymer polyol preparation, then production efficiency increases, but equipment complexity increases requiring both continuous and semi-batch equipment
Solution Approach 1:
The patent segments the polymerization process into distinct stages: a seed polymerization stage followed by a main polymerization stage. This segmentation can be achieved in a single batch reactor or semi-batch reactor, eliminating the need for complex continuous processing equipment while maintaining high productivity through efficient process 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
This process results in polymer polyols with improved cell opening and reduced crushing force, facilitating the production of flexible polyurethane foams with enhanced properties.
Implementation Method 1
polymerizing in a base polyol at least one ethylenically unsaturated monomer in the presence of a polymerization initiator
Data Source
AI summary
The invention relates to a process for the batch or semi-batch preparation of a polymer polyol, which process involves (1) preparing a seed by polymerizing in a base polyol at least one ethylenically unsaturated monomer in the presence of a polymerization initiator and macromer, and in the presence of from 0.5 to 50% wt of polymer polyol heel, based on amount of polymer present in the heel compared with total amount of polymer formed, (2) adding additional ethylenically unsaturated monomer to the seed obtained in step (1) and optionally additional polyol, and (3) polymerizing the mixture obtained in step (2).