Quality Control Tests and Matching Fourier‐Transform Infrared Spectra for Raw and Intermediate Materials of 2‐Pack Epoxy Paints

Abstract

Summary The local users of the oil and gas companies suffering from high cost of repainting the steel structures and pipelines when the coatings fail prematurely, where one of the attributing factors may be the adulterated polymeric coatings supplied to the job sites. This posted the needs to fingerprint the polymeric coatings supplied, which shall not deviate from the submitted specifications for prequalification and tender purpose of projects. The first part of the study shows that the coatings formula remains trade secret, even though spectra of Fourier‐transform infrared spectroscopy (FTIR) are submitted along with the delivery of the polymeric coatings. Characterizations of the raw materials (viscosity and density) as well as final products (adhesion and dry film thickness) can hardly be differentiated for different grades of materials with exception on the salt spray test. The salt spray test is usually performed before the paint manufacturer submits its product for qualification and tender purpose. Infrared component searching of various raw and intermediate paint materials ranging from organic color pigments, epoxy resins to epoxy hardeners for 2‐pack epoxy paints was attempted. The materials were analyzed with FTIR. It appears that the component search gives several possible (chemical) compounds according to extensive FTIR library search. Although some of these components are known to exist within the material (color pigments, epoxy resins and epoxy hardeners), it does not reveal further detailed formulation. Reproducibility of the estimation of correlation (r) or the matching ratio of the reference spectrum to that of the sample spectrum is noted when the FTIR analysis was carried out. The statistical examination utilizing two‐sample paired t‐test shows that there is no statistically difference at 95% confidence level for the results of r estimated between Softwares A and B, or between Softwares A and C when the samples were analyzed using Nicolet FTIR spectrometer.

Batch‐to‐Batch Reproducibility Studies of Pilot‐Scale Emulsion Polymerization of Poly(styrene‐co‐butyl acrylate)

“…The product formula for paint or ink manufacturers is always a trade secret. Single‐component of FTIR library search was attempted using the sample spectra searching on the extensive commercial FTIR library using library “search” feature in the OMNIC software …”

Mid and Far Fourier‐Transform Infrared Authentication Analysis for Polymeric Paints and Their Raw Materials

“…On top of this, refs. [29,30] show the extensive FTIR library matching search for various organic raw materials and 2-pack epoxy paints, using three different commercial FTIR libraries. The matching result exhibits many possible chemical compounds in the formulation, which are not in close approximation to the actual formulation of the raw materials or paints.…”

“…These inhibitors work by the concept of cathodic protection against the protected steel structures. [25][26][27] In previous studies, the evaluation protocol using ATR-FTIR technique with high sensitivity compare function were successfully used on two-pack epoxy paints [2,3,[28][29][30] and their raw materials. [31,32] Good correlation between the batch-to-batch consistency, with the degree of similarity (r) ≥ 0.900 ± 0.002, for different batches of paint as well as the physical tests were recorded.…”

“…[2,3] On top of this, this protocol is not limited to a single brand of FTIR spectrophotometer and software, but also it does not reveal the trade secret or the paint formulation via extensive FTIR commercial library search. [3,29,30] With the availability of many raw material suppliers in the market and price differences, concerned parties (paint manufacturers) prefer to source specific raw materials from different suppliers of one region or different regions. Hence, the consistency of different batches or authentication of raw materials from different suppliers is crucial for the consistency performance of final products.…”

Fourier transform infrared (FTIR) authentication and batch‐to‐batch consistency for different types of paints using benchtop and handheld FTIR spectrophotometers for oil and gas industry

“…Chan et al proposed this procedure for the detection of homogeneity at different locations of the mixing tank for different paints [ 6 ] and for the distinction between normal‐grade and premier‐grade raw materials used for epoxy paints. [ 7 ] Different FTIR manufacturers and software used for the estimation of r values by normal and high sensitivity compare function were also investigated. [ 8 ] The sensitivity differs slightly according to different numerical approaches which are pre‐installed in the software.…”