Urethane Polyisocyanate Composition for Additive-Free Storage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyisocyanates used in polyurethane paints and adhesives often suffer from agglomeration or solid precipitation during storage, especially at lower temperatures, which complicates their use and increases process complexity and raw material costs when addressed with additional additives like organic acids or high molecular weight polyethylene glycol.
Innovation Solution
A urethane group-containing polyisocyanate is prepared by reacting organic polyhydroxy compounds with excess toluene diisocyanate, maintaining a specific molecular weight ratio and viscosity, and removing unreacted toluene diisocyanate to enhance storage stability without additional additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional additives like organic acids or high molecular weight polyethylene glycol are used to address agglomeration, then storage stability is improved, but process complexity and raw material costs increase
Solution Approach 1:
The patent removes the need for additional additives by optimizing the molecular weight distribution of the polyisocyanate itself. Through controlled reaction conditions and selective removal of specific molecular weight fractions (particularly the 950±50 g/mol shoulder peaks), the invention achieves storage stability without requiring organic acids or high molecular weight polyethylene glycol additives, thereby simplifying the process and reducing costs
Solution Approach 2:
The invention changes the critical parameter of molecular weight distribution within the polyisocyanate product. By controlling the ratio of component peaks (800±50 g/mol) to shoulder peaks (950±50 g/mol) to be between 2-14 and maintaining viscosity ≤2500 mPa·s, the product achieves inherent storage stability without additional additives, resolving the contradiction between reliability improvement and process simplification
2Stability of the object's composition
If heating treatment is applied to resolve agglomeration, then product clarity is restored, but ease of use deteriorates due to additional operational complexity
Solution Approach 1:
The patent applies preliminary action by controlling the molecular weight distribution during the manufacturing process to prevent agglomeration from occurring in the first place. By optimizing the polyisocyanate structure beforehand (controlling peak ratios and viscosity), the product remains stable during storage without requiring subsequent heating treatment, thereby maintaining ease of use while ensuring product clarity
3Reliability
If high molecular weight components are present in the polyisocyanate, then viscosity increases, but storage stability improves
Solution Approach 1:
The patent applies local quality by making a nuanced distinction between different molecular weight ranges. Rather than simply increasing overall molecular weight, the invention selectively maintains components in the 800±50 g/mol range while removing the problematic 950±50 g/mol shoulder peaks. This localized optimization achieves storage stability without the excessive viscosity that would result from uniformly high molecular weight components
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 resulting polyisocyanate exhibits high isocyanate group content, low viscosity, and improved storage stability, forming hard yet elastic paint films with excellent adhesion and abrasion resistance on various substrates, while avoiding agglomeration.
Implementation Method 1
after the excess toluene diisocyanate reacts with hydroxy compounds, organic acids having a pKa value of 1 to 15 are added to the reaction mixture, and then the excess toluene diisocyanate monomer is separated at a high temperature by a thin-film evaporator
Data Source
Figure 1
AI summary
The present invention relates to a urethane group-containing polyisocyanate prepared by reacting a system containing organic polyhydroxy compounds and excess toluene diisocyanate and, a process for preparing the same, a product containing the polyisocyanate, and the use thereof as a polyisocyanate component in a polyurethane paint and a polyurethane adhesive. The polyisocyanate has the following characteristics: a. the ratio of the integral area of the component peaks having a. weight-average molecular weight of 800±50 to the integral area of the shoulder peaks having a weight-average molecular weight of 950±50 is 2-14; and b. the viscosity is not higher than 2500mPa s. The polyisocyanate of the present invention has a good storage stability.