Comb-Type Copolymer Additives for TiO2 Opacity in Paint
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Solution Overview
Problem
The challenge is to reduce the quantity of titanium dioxide (TiO2) particles in paint formulations without compromising optical qualities, as the use of dispersants often leads to flocculation and agglomeration during the drying process, which affects the opacifying effectiveness and requires additional pigments to maintain performance.
Innovation Solution
The use of water-soluble comb-type copolymers with an acid skeleton and polyalkylene glycol branches, which act as spacing molecules to prevent flocculation and maintain the separation of TiO2 particles during the drying process, allowing for a reduction in TiO2 usage while maintaining optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dispersants are used in paint formulations to maintain TiO2 particle separation, then particle distribution is improved, but flocculation occurs during drying which reduces opacifying effectiveness
Solution Approach 1:
The patent introduces a specific water-soluble comb-type copolymer as an intermediary substance that mediates between TiO2 particles and the paint matrix. This copolymer, with its acid skeleton and polyalkylene glycol branches, acts as a spacer that maintains particle separation during drying without causing flocculation, thus preserving both stability and opacifying effectiveness
Solution Approach 2:
The patent changes the chemical parameters of the dispersant system by using a specific copolymer composition (acid skeleton with polyalkylene glycol branches) instead of conventional dispersants. This parameter change allows the system to maintain particle separation throughout the drying process, preventing the flocculation that normally occurs with standard dispersants
2Quantity of substance
If the quantity of TiO2 particles is reduced to lower costs, then material cost decreases, but optical qualities deteriorate
Solution Approach 1:
The copolymer acts as a spacer that maximizes the optical effectiveness of reduced TiO2 quantities by preventing particle aggregation. This intermediary substance ensures that each TiO2 particle remains individually dispersed and optically active, allowing cost reduction through lower TiO2 content while maintaining illumination and opacity properties
3Length of moving object
If additional pigments are added as expander/spacer particles to maintain TiO2 separation, then particle spacing is improved, but agglomeration occurs during drying which compromises optical qualities
Solution Approach 1:
The patent extracts the spacer function from the pigment system itself. Instead of using additional pigment particles as spacers (which causes agglomeration), the invention uses a molecular spacer (the copolymer) that provides separation without the mass and aggregation problems of pigment-based spacers
Solution Approach 2:
The copolymer serves as an intermediary that provides particle spacing without the drawbacks of using additional pigments. This molecular mediator maintains the required distances between TiO2 particles during drying while avoiding the agglomeration that occurs with pigment-based spacer systems
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 approach effectively increases the effectiveness of TiO2, enabling a reduction in its quantity without deteriorating paint performance or modifying rheological properties, and can achieve this with low doses of the copolymer, maintaining high opacity and clarity indices.
Implementation Method 1
Without wishing to be bound by any theory, in view of the results obtained, the inventors are of the opinion that the copolymers according to the invention have steric hindrance properties which make it possible to space out the TiO2 particles in paint formulations, and also to maintain the separation of the TiO2 particles during the drying stage of the paint film
Implementation Method 2
Documents EP 1 270 687 and EP 1 070 739, for their part, describe the use of polymer particles adsorbed on the surface of pigment particles
Data Source
AI summary
The present invention concerns the use of new additives in a paint formulation comprising titanium dioxide particles (Ti02) as agents improving the opacity of the dry or drying film, and paint formulations comprising such agents.