Surface-Modified Pigment Preparations for High-Solids Coatings

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Solution Overview

Problem

There is a need for surface-modified pigment preparations with improved rheological and dispersing properties, especially in high-solids coating systems, that do not adversely affect the coloristic properties of the pigments and can be used in partially crystalline plastics without causing warping.

Innovation Solution

A pigment preparation is achieved by covalently attaching an organic group to the chromophore of the pigment surface through grafting free radicals, using a process that involves treating a suspension of organic pigments with azo or peroxy compounds to generate radicals, which then attach to the pigment surface, enhancing dispersibility and stability without altering the color properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If organic pigments are used at high concentration, then color strength is improved, but dispersibility and rheology deteriorate

Engineering Contradiction:

Improvepigment concentrationVSAvoiddispersibility

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The invention changes the chemical parameters of the pigment surface by introducing specific functional groups (carboxylic, hydroxyl, amino groups) through grafting reactions. This modifies the surface properties of the pigment particles, improving their interaction with the dispersion medium and thereby enhancing dispersibility at high concentrations without sacrificing color strength.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure on the pigment surface by grafting organic compounds containing multiple functional groups. This composite approach combines the color-generating core of the pigment with surface-modifying groups that provide dispersibility and rheological control, allowing high concentration use while maintaining ease of operation.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If pigment surface is modified to improve dispersibility, then dispersing properties are improved, but coloristic properties may be adversely affected

Engineering Contradiction:

Improvedispersing propertiesVSAvoidcoloristic properties

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The invention applies local quality modification by introducing functional groups specifically at the pigment surface while leaving the bulk chromophore structure unchanged. The grafting occurs only on the particle surface, providing improved dispersing properties locally without affecting the color-generating properties of the core pigment structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses the pigment surface as an intermediary between the color-generating chromophore and the dispersion medium. By grafting functional groups on the surface, it creates an intermediate layer that improves interaction with the medium while protecting the underlying chromophore from direct exposure to the dispersion environment, thereby preserving coloristic properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If pigment surface is modified to improve rheology, then rheological properties are improved, but processing complexity increases

Engineering Contradiction:

Improverheological propertiesVSAvoidprocessing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The invention enables self-service rheology control through the intrinsic properties of the grafted functional groups. The carboxylic, hydroxyl, and amino groups on the pigment surface automatically interact with the dispersion medium and each other, providing self-regulating rheological behavior without requiring complex external processing or additional rheology modifiers.

Inventive Principle:

Principle #25Self-service

4Ease of operation

If conventional surface modification techniques are used, then dispersibility is improved, but warping occurs in partially crystalline plastics

Engineering Contradiction:

ImprovedispersibilityVSAvoidwarping

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

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 modified pigments exhibit improved dispersibility, stability, and rheological properties, allowing for effective use in high-solids coatings and partially crystalline plastics without warping, while maintaining the original color characteristics.

Implementation Method 1

treating a suspension of organic pigments with azo or peroxy compounds to generate radicals

Methodology Applied

Scientific EffectFree radical generation: Decomposition (biological)

Implementation Method 2

covalently attaching an organic group to the chromophore of the pigment surface through grafting free radicals

Methodology Applied

Scientific EffectFree radical grafting: Chemical Bonding

Data Source

PatentEP2658928B1Surface-modified pigment preparations

Publication Date: 2019.03.27 BASF SE

AI summary

A pigment preparation is provided, said preparation comprises an organic pigment comprising a chromophore Q1 and a derivative thereof comprising specific organic substituents via an aliphatic carbon atom in an amount of from 0.1 to 30 mol, based on 100 mol of the organic pigment as well as a process for its preparation and to its use in coloring an organic material such as plastics, coatings or inks.