Nonionic Associative Thickeners for Viscosity Stability
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Solution Overview
Problem
Existing thickeners for waterborne compositions, especially those with high pigment concentrations, face challenges in maintaining viscosity stability and compatibility with intense pigments, leading to undesirable viscosity reductions and application property compromises.
Innovation Solution
Development of nonionic associative thickeners with specific polyether polyol polymer/hydrophobe melts, incorporating isocyanurate trimer and di-isocyanate, which form hydrophilic and hydrophobic interactions to stabilize viscosity in waterborne compositions containing high pigment loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional thickeners are used in waterborne compositions with high pigment concentrations, then the composition can be formulated, but the viscosity drops significantly and application properties are compromised
Solution Approach 1:
The patent modifies the chemical structure of associative thickeners by changing the isocyanate ratio (NCO-OH ratio from conventional 0.4-0.6 to 0.7-1.3) and molecular weight parameters to optimize hydrophobe-hydrophile balance. This structural parameter change enables the thickener to maintain viscosity stability in high pigment concentrations by adjusting the density and distribution of hydrophobic associations.
Solution Approach 2:
The patent creates a composite molecular structure combining polyether polyol blocks with aromatic hydrophobe groups (e.g., naphthalene, anthracene) linked through urethane bonds formed with polyisocyanates. This composite structure integrates both hydrophilic (polyether) and hydrophobic (aromatic) segments in a single molecule, enabling dual functionality: water solubility and strong associative thickening in high pigment systems.
2Stability of the object's composition
If nonionic associative thickeners with specific structures are developed, then viscosity stability is maintained, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs preliminary action by pre-synthesizing block copolymer polyether polyols with controlled molecular weights and hydroxyl end groups before the final thickening step. This pre-preparation of standardized polyol blocks simplifies the overall manufacturing process, as these standardized intermediates can be consistently produced and then combined with hydrophobe/isocyanate components in a controlled final reaction step.
Solution Approach 2:
The patent optimizes reaction parameters including NCO-OH ratio (0.7-1.3), molecular weight ranges of polyether blocks (45-275 units), and hydrophobe content (0.1-10 wt%) to achieve viscosity stability while maintaining manufacturability. These specific parameter ranges balance performance requirements with process control feasibility, avoiding overly complex manufacturing while achieving the desired viscosity stability.
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 nonionic associative thickeners maintain viscosity stability within 70-100% of initial values even with high pigment concentrations, improving shear viscosity, spatter resistance, and gloss retention, unlike conventional thickeners which see significant drops in viscosity.
Implementation Method 1
The polyether polyol polymer/hydrophobe melt may be heated at a temperature sufficient to produce the nonionic associative thickeners described herein
Implementation Method 2
An isocyanurate trimer and a di-isocyanate may be introduced to the polyether polyol polymer/hydrophobe melt. After introduction of the isocyanurate trimer and di-isocyanate compositions, the polyether polyol polymer/hydrophobe melt may be heated at a temperature sufficient to produce the nonionic associative thickeners described herein
Data Source
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AI summary
Compositions and methods of making urethane based nonionic associative thickeners are described herein. Uses of the nonionic associative thickeners are also described.