The Waterborne Symposium 2025

Co-Authors:  Yelone Liu and Hugo Wang

Abstract

The use of plastics in different applications, such as automotive interiors and consumer electronics, has increased mainly due to their low density and light weight, convenient processability and balance of cost and performance. However, many plastics require a coating to protect the surface from scratches and abrasion to maintain their surface appearance and quality. This is particularly challenging in low gloss coatings (≤ 5 gloss units at 60°) where the film damage is easily visible. The thin films used also limits the ability of some additive technologies to improve coating durability.

This paper presents a study of different synthetic silica matting agents in combination with other additives in four different plastic coating formulations and compares their effects on scratch and abrasion resistance of the final coating. Conventional silica matting agents offer good dispersibility and matting efficiency, but their scratch and abrasion resistance does not meet end-user expectations. Organic / polymeric matting agents have better scratch and abrasion resistance but are less efficient in matting. Combinations of silica matting agents with other technologies, such as nylon powders or polyethylene waxes can dramatically improve the scratch resistance without side effects. Abrasion resistance can be enhanced using combinations of matting agents with novel small-sized, spherical silica particles..

Co-Authors:
R. Severac, T.T. Tran, C. Kustner, A. Becker, G. Schlatter, S. Le Calve , A. Hebraud

Abstract
"Driven by environmental, health, and safety concerns, coatings technologies have undergone a dramatic shift in the past few decades driven by the reduction of VOCs and other hazardous materials in coating formulations. The continuous development and improvement of waterborne technologies has enabled many solvent-based systems to be replaced with waterborne chemistries that contain significantly lower VOC content than their solvent-based counterparts. VOC levels have been pushed even lower by the development of low-VOC and zero-VOC water-based formulations. A continuation of this trend emerging in the global coatings industry has been focused on the development of functional coatings that not only limit emissions of VOCs into the environment but actively extract and remove VOCs that have originated from other sources. A functional coating with VOC remediation capability could improve indoor air quality and provide a means to scavenge VOC emissions from sources that have proven to be more challenging to address.

This investigation is based on two different methodologies. In a first part, ISO 16000-23 European standard has been used as an initial demonstration of the formaldehyde scavenging efficiency of a conventional zero-VOC decorative paint containing tris (hydroxymethyl) aminomethane and 2-amino-2-ethyl-1,3-propanediol. Even if extended to 6 weeks, this dynamic test is not able to determine the real full scavenging capacity of the studied material. A new method has been developed with the intend to experimentally measure the full capacity of adsorption, and also to test several pollutants present in indoor environment over formaldehyde, enabling to characterize the scavenging versatility of these additives".

Abstract

Block copolymer (BCP) thin films have a wide range of applications from membrane technologies for gas separation to energy applications including solid electrolytes. The nanoscale morphology of BCPs plays a critical role in the bulk material properties and subsequent applications. In addition to chemical structure, various processing conditions have been demonstrated to impact BCP morphology and can be leveraged as tunable parameters. To achieve precise control over BCP solid state morphology, processing conditions require optimization. This talk presents a novel approach for the high throughput analysis of grazing incidence small-angle x-ray scattering (GISAXS) data and atomic force microscopy (AFM) images, characterizing BCP thin film morphology. The curated dataset was used to train 11 unique machine learning (ML) models to predict BCP morphological properties from processing parameters including solvent ratio and additive amount. ML models were able to relatively accurately predict the extent of ordering of BCP thin films measured by GISAXS but struggled with AFM measurements. The decreased performance by the models predicting the AFM-based measurements can be attributed to the variability within the AFM measurements. Despite this variability, a convolutional neural network (CNN) trained on the AFM images was highly accurate, correctly classifying over 93% of images into ordered/disordered categories. While performance of ML models is crucial, interpretability of the predictions is equally important. For this purpose, the Shapley Additive exPlanations (SHAP) was used to interpret the predictions of the models. Additive amount was the most influential processing parameter on morphological output predictions, which agrees with the physical understanding of the system. Additionally, the SHAP deep explainer demonstrated the successful interpretation of the AFM images by the CNN. This framework leveraging ML and high throughput data analysis lays the foundation for BCP thin film processing optimization with an expanded design space.

Abstract

The colloidal capability team at PPG focuses on understanding how colloidal properties such as particle size and particle-particle interactions drive the stability and performance of paint formulations. The colloidal system emphasized in this talk is pigments, which are ubiquitous in the coatings industry and play a crucial role by providing properties such as color, opacity, protection, and durability. Furthermore, pigment stability against sedimentation and aggregation is essential to ensure that these properties remain consistent over time, even when exposed to changing environmental conditions. In this talk, we will present techniques that efficiently assess the stability of pigments and fundamental properties that drive it. 

Co-Authors: Hieu Ngo, Daniel Scholz

Abstract:
The market demand to replace dyne pens for faster, more accurate contact angle and surface energy results which can be made directly in the production area has fueled the development of very sophisticated portable, handheld contact angle goniometers. These devices are growing in popularity and allow immediate measurement of contact angle and surface energy with minimal operator expertise or training required. However, the question arises as to how results obtained using such a handheld device with two test liquids will compare in accuracy and repeatability to the more traditional, lab-scale devices which offer the ability to make high-speed movie measurements of droplet spreading and use as many as three or even four different test liquids. This lecture will compare and contrast contact angle and surface energy results obtained using both a handheld versus a lab-style research-grade contact angle goniometer. Real-world advantages and disadvantages of these two types of measurement devices will be presented.