Salt-Modified Copolymer Dispersants for Color Filter Pigments
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Solution Overview
Problem
In color filter applications, the increasing demand for smaller pigment particle sizes for better color properties and higher throughput in photolithographic processes makes dispersing these particles more difficult, and existing dispersants do not adequately improve dispersibility and development properties.
Innovation Solution
The development of salt-modified copolymers containing a quaternized N-atom structure with a polar substituent, synthesized through controlled or conventional polymerization, which acts as a dispersant to enhance the dispersibility and development properties of pigments in color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pigment particle size is reduced for better color property, then color property is improved, but dispersing becomes more difficult
Solution Approach 1:
The patent modifies the chemical structure of dispersant molecules by introducing quaternized N-atom structures with polar substituents (such as carboxylic acid, sulfonic acid, phosphoric acid groups). This parameter change in the dispersant's molecular architecture enhances its ability to interact with and disperse ultrafine pigment particles, resolving the contradiction between achieving small particle size for color quality and maintaining dispersibility.
Solution Approach 2:
The invention creates a composite system combining quaternized polymer dispersants with multifunctional polar groups and pigment particles. This composite approach forms effective dispersant-pigment complexes that stabilize ultrafine particles, allowing simultaneous achievement of improved color properties through particle size reduction and maintained dispersing performance.
2Ease of manufacture
If conventional salt-formed dispersants are used, then dispersing function is provided, but development property is not optimum
Solution Approach 1:
The patent fundamentally changes the parameter of the dispersant's functional groups by incorporating polar substituents (carboxylic acid, sulfonic acid, phosphoric acid) alongside the quaternized N-atom structure. This parameter modification enables the dispersant to perform both dispersing and development functions effectively, optimizing photolithographic development properties while maintaining dispersing capability.
Solution Approach 2:
The quaternized dispersant with polar substituent serves multiple functions simultaneously: it acts as a dispersing agent for pigment particles and as a development promoter for photolithographic processes. This multi-functionality resolves the contradiction by providing both adequate dispersing performance and optimal development properties through a single dispersant molecule.
Data Source
AI summary
The present invention pertains to salt modified copolymers wherein one of the monomer units contains a quaternized N-atom structure with a polar substituent. The invention further relates to the use of said copolymers as dispersant especially for color filters. The copolymer is made by controlled polymerisation or by conventional polymerization and comprises at least one monomer (MAr) selected from unsaturated monomers out of the group of acrylates, methacrylates, acrylamides, methacrylamides, styrenic monomers, at least one monomer (MBs) selected from unsaturated monomers out of the group of acrylates, methacrylates, acrylamides, methacrylamides, styrenic monomers wherein the monomer MB has a quaternized N-atom structure with a polar substituent selected from polyether, polyamine, nitrile, amide, imine, imide, ester, ketone, nitrile, aldehyde, diketone, ketoester, ketoamide, carbonate, carbamate, carbamide, sulfoxide, sulfone, carboxylic acid, sulfonic acid, phosphoric acid groups; or carboxylic acid anion, sulfonic acid anion or phosphoric acid anion groups which is formed as betaine structure r denotes the total number of monomers MA within the structural element (MAr) and r is > 5, preferred 10-1000, most preferred 10-500; s denotes the total number of monomers MB within the structural element (MBs) and s is > 1, preferred 2-100, most preferred 2-50.