Pigments

A pigment may be described as a substance that modifies the color of another substance to produce a product that provides identity (pharma tablets and capsules, monetary currency), warning (stop signs), living enhancement (cosmetics, house paint), artful pursuits (artwork) and general utility (printer inks). Pigments generally have properties that allow for selective absorption and reflection/refraction of particular wavelengths and frequencies of light. White light contains many frequencies of light. When a wave of light encounters a colored substance, the light not absorbed, but reflected or refracted into the observer’s eyes provides the color observed. Thus color and the need for pigments affect and enhance all facets of life.

Pigment Particle Size Using Microtrac Laser Technology describes the general measurement of all pigment types using the Microtrac patented tri-laser diffraction analyzer.

Powder Coatings

The performance of a powder coating is influenced by a variety of factors. Powder particle size can have a major influence on many properties, including handling, charging, delivery, and coating characteristics. The formulations may vary depending on application requirements of thickness, object shape, and ambient conditions. Particle size strongly influences film thickness because fines produce thin initial powder coats and coarse particles produce thick initial powder coats. As a result, the heated coats melt at different rates, decreasing the smoothness of the final coating.

Powder Coatings and Particle Size Measurement describes how Microtrac particle analyzers use a proprietary algorithm that allows direct conversion of scattered light to a volume distribution. Measurement is fast, easy, and precise with the patented silicon detector array.

Printer Inks

Modern printing inks contain many components each having a specific purpose in maintaining color, intensity, dispersion, viscosity, as well as acting as a milling aide. The colorant can be of two types: pigment or dye. Dyes are very small molecules usually considered to be in complete solution. Molecules smaller than 1 nm are considered to be in solution while those larger than 1nm are considered to be in suspension. Pigments are used and are considered to be in suspension (not solution) and may be either organic or inorganic in chemical composition.

Printer Ink Nanosize Measurement describes how Nanotrac has the capability to measure inks of all colors including black, magenta, yellow and blue. The measurement can be conducted using high concentrations and can reveal special distribution features such as bi-modal distributions and changes in particle size.

Challenges of Obtaining Valid Particle Size Data in Inkjet Inks

Application of DLS to UV/EB Cure Coatings

Abstract
For digital inkjet inks, particle size analysis is important to ensure proper jetting of the ink through the printer head and is an indicator of color development and transparency. The measurement of particle size of pigments in the nanometer range, such as those used in inkjet inks, brings with it a number of challenges. In this paper, the authors briefly review particle size measurement methodologies and will specifically address the challenges faced by formulators and analysts when making these measurements. In order to obtain meaningful information, one must understand the measurement principles and limitations of the methodology selected, the criticality of sample preparation, and understand the measurement parameters and variables and how they can affect the results. Examples will be used to illustrate the potential impact of many of these variables and recommendations will be offered to assist formulators and analysts collect valid data from which meaningful information can be drawn.

Jeremy Powers and Kristine Eisemon, Plasticolors Inc., Ashtabula, Ohio USA

Applications & Industries