Automotive Coatings Research Articles

Scratch Properties of Clear Coat for Automotive Coating Comprising Molecular Necklace Crosslinkers with Silane Functional Groups for Various Environmental Factors

Automotive coatings, which comprise multiple layers, i.e., primer, base coating, and clear coat layers, are exposed to various environmental conditions that pose various types of damages to them. In particular, the outer layer of the automotive coating, i.e., the clear coat, is affected significantly by such damages. Therefore, a reliable and durable clear coat must be developed to improve the appearance of automobiles. In this study, a new clear coat based on an acrylic-based clear coat modified using polyrotaxane crosslinkers, which are necklace-shaped supramolecules composed of ring-shaped host molecules, is developed and characterized. The effects of polyrotaxane and silane on the scratch properties and mechanisms of the clear coating are analyzed. It is observed that the critical loads of the clear coat from scratch tests can be improved by adding optimal molecular necklace crosslinkers comprising silane functional groups. The improvement in the scratch properties of the modified acrylic-based clear coat may be attributed to the crosslinking characteristics and dynamic molecular movements of the polyrotaxane. In addition, the effects of environmental factors on the scratch characteristics of the modified acrylic-based clear coat are investigated by addressing the scratch durability of the clear coat.

Assessment of Selected Properties of Varnish Coating of Motor Vehicles

The technology and methods of testing the properties of varnish coatings used in motor vehicles are constantly and successfully developed. However, in the case of automotive varnish renovation coatings used in the repair of car bodies, the problem of fitting the quality of these coatings to the quality and current condition of the coating applied to undamaged vehicle components is not definitely solved. The main goal of the research was to determine the thickness and gloss distribution of the varnish coatings. The thickness and gloss of the varnish coating on the entire body of the vehicle were measured. Classical methods of assessing these properties were used. Defects in the renovation coating were also simulated, to show their negative impact on the varnish quality. The performed tests allowed for development of a procedure and algorithm for evaluation of the quality of the car’s renovation coating after the repair of the car body. The proposed procedure, expressed with the presented algorithm, allows to fit the obtained renovation coating to the quality and condition of the coating manufactured in factory on the car body in the range of its thickness up to 270 µm and gloss in the range of 5–90 GU. The developed procedure for the assessment of renovation coatings can be used in workshops that repair vehicle bodies. This will allow to improve the quality of renovation coatings and bring their properties, such as thickness or gloss, closer to those applied to the vehicle’s body at the factory.

Colorants in coatings

AbstractThe aim of this chapter is to provide a compact overview of colorants and their use in coatings including a brief introduction to paint technology and its raw materials. In addition, it will focus on individual colorants by collecting information from the available literature mainly for their use in coatings. Publications on colorants in coatings applications are in many cases standard works that cover the wider aspects of color chemistry and paint technology and are explicitly recommended for a more detailed study of the subject [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. Articles or information on paint formulation using coatings which contain colorants are rare [19]. This formulation expertise is often company property as it is the result of many years of effort built up over very long series of practical “trial-and-error” optimization tests and, more recently, supported by design of experiment and laboratory process automation [20, 21]. Therefore, it is protected by rigorous secrecy agreements. Formulations are in many ways part of a paint manufacturer’s capital, because of their use in automotive coatings, coil coatings, powder coatings, and specialist knowledge is indispensable to ensure their successful industrial use [22]. An important source to learn about the use of pigments in different coating formulations are guidance or starting formulations offered by pigment, additive, and resin manufacturers. These are available upon request from the technical service unit of these companies. Coating formulations can also be found scattered in books on coating and formulation technology [4, 5, 18, 23,24,25,26,27]. This overview can in no way claim to be complete, as the literature and relevant journals in this field are far too extensive. Nevertheless, it remains the author’s hope that the reader will gain a comprehensive insight into the fascinating field of colorants for coatings, including its literature and current research activities and last but not least its scientific attractiveness and industrial relevance.

Review of THz-based semiconductor assurance

Terahertz radiation for inspection and fault detection has been of interest for the semiconductor industry since the first generation and detection of THz signals. Until recent hardware advances, THz systems lacked the signal quality and reliability for use as an effective nondestructive testing (NDT) method. Incremental advances in THz sources, detectors, and signal processing resulted in the successful applied-industrial use of THz NDT techniques on carbon fiber laminates, automotive coatings, and for detection of counterfeit pharmaceutical tablets. Semiconductor inspection and verification methods ensure the functionality and thereby safety of vital electronics for several critical industries. For this reason, the reliability and verification of a THz NDT method must exceed currently used inspection systems. With recent laboratory access to THz radiation, THz inspection methods are often compared with existing optical, electrical, and volumetric semiconductor verification techniques for their production monitoring and failure analysis viability. This review will cover THz techniques and their applications at the printed circuit board (PCB), integrated circuit (IC), and transistor/gate scales. The THz radiation gap spans between optical and electronic ranges with a millimeter-sized wavelength allowing for adequate penetration of plastic and ceramic and semiconductor materials. THz radiation can be used to determine structural features, electrical signatures in the THz range, and chemical information simultaneously. Cost and environmental limitations restricted the ability for THz NDT semiconductor inspection methods to escape the lab and succeed in the dynamic environment of a semiconductor fabrication environment. Hybridized metrology methods incorporating information from multiple inspection tools are a regime where THz spectral and structural data can be combined with existing methods such as optical, x-ray, or E-beam. THz can be used initially to offer support to the complex failure analysis and verification requirements of the semiconductor industry from nanoscale to macroscale features and components. For THz systems to become independent inspection tools used for semiconductor production monitoring, in the lab or fab, this will require a confident level of statistical process control for THz signal generation, detection, or processing. Applied industrial semiconductor device inspection will likely be a result of a combination of research into THz hardware, reconstruction techniques, and the widespread application of machine learning techniques. Many breakthroughs occurred over the years to enable successful nondestructive characterization and inspection of semiconductor devices from the nanoscale transistors to fully packaged integrated circuits and assembled PCBs.

PPG acquires automotive coatings manufacturer Cetelon

PPG acquires automotive coatings manufacturer Cetelon

Numerical Simulation of Cracks in Automotive Coatings Under Mechanical and Thermal Loading Using Element Free Galerkin Method

ABSTRACT The work presented in this paper aims to delve into the applications of Element Free Galerkin Method (EFGM) which is a type of Meshless Method (MM) to the area of Automobile Engineering. EFGM is implemented to detect a change in the material property at the interface of the coating along with the identification of crack. Simulation of centre crack in coatings has been reported for the first time using EFGM. Simulations with change in crack inclination angle, change in crack length are reported. Multiple cracks are reported in the form of collinear cracks, coplanar cracks and the effect of their presence on primary crack has been discussed. This work involves the study which leads to understanding the effect of temperature on the stress fields of the cracks present in coatings. Variations of the temperature field parallel to crack and perpendicular crack shows enticing results. The effect of variation in materials properties of coating and substrate is discussed. The work reveals the nature of crack severity in automobile coatings. Various conditions depicted in this work enhance the understanding of researches in comprehending the effect of thermal load in coated materials.

A Short Review on Self‐Healing Thermoplastic Polyurethanes

AbstractThermoplastic polyurethane (TPU) is a melt‐processing polymer with a high elasticity, high tensile strength, low‐temperature resistance, wear‐resistance, and corrosion resistance ability. TPU can be used in the automotive industry, electronics, medical supplies, coatings, and sports equipment. Introduction of self‐healing performance has made a considerable contribution to the service life and recyclability of TPU. The present article analyzes recent progress in self‐healing supramolecular TPUs. In particular, the importance of self‐healing mechanisms governed by covalent bonds and non‐covalent interactions in polymer design that allows for balancing mechanical performance and repairability is summarized. The critical issues and challenges associated with self‐healing supramolecular TPUs are also discussed.

Hyperbranched additive into a high solid acrylate coating for automotive application: impact on performance and emission of volatile organic content

PurposeAutomotive coating materials are very important items for this industry. However, their performance is limited by the use of excessive amounts of solvents in their formulations, whereas the emission of volatile organic solvents is against the widely ascending principle of green chemistry. Thus, this study aims to overcome this global problem to save the environment without affecting the properties and performance of the coating.Design/methodology/approachHigh solid content paint formulation for automotive applications has been designed with low amount of volatile organic solvents with the aid of a functionalized hyperbranched modifier.FindingsIt was found that the presence of a hyperbranched additive allows a high solid content to be designed and facilitate the processing, which indicates its liability to compensate the role played by excessive solvents amounts. In addition, the mechanical properties and physical characteristics of the modified coatings showed outstanding performance and preservation of clarity in comparison with the commercial counterparts.Practical implicationsA high solid content coating with facile processing and improved performance leads to cheaper price beside the positive impact on the environment considering the limited emission of volatile organic contents.Social implicationsLimitation of the used volatile organic compounds in any industry helps to save the health of humans and keep the environment unaffected.Originality/valueThe use of functionalized hyperbranched additive to automotive coatings is a very promising additive for automotive coatings with optimized characteristics.

Photonic Crystals: Spray Synthesis of Photonic Crystal Based Automotive Coatings with Bright and Angular‐Dependent Structural Colors (Adv. Funct. Mater. 9/2021)

In article number 2008601, Jianping Ge and co-workers prepare photonic crystal automotive coatings with bright, durable, and angular-dependent structural colors via a two-step spraying process. The paint solvents are studied to achieve a quick formation of a liquid photonic crystal intermediate and then a highly crystalline photonic coating with monochromatic colors, based on which more gradient colors among red, green, and blue are created.

Perspective of sol-gel hydrophobic silica deposited using low-pressure cold spray and ultrasonic atomizing for automotive coatings

The automotive sector is under constant pressure to minimize fuel consumption and reduce pollution emissions while maintaining a declining tendency for weight and cost reduction. This makes the material selection process a major of engineering design considerations. In the paper, the main automotive requirements were formulated to analyze the potential of selected deposition (low pressure cold spray and ultrasonic atomizing) and material fabrication (sol-gel method) techniques for application in the automotive industry.

자동차용 고체윤활코팅의 고장 메커니즘과 수명 예측 기술 연구

자동차용 고체윤활코팅의 고장 메커니즘과 수명 예측 기술 연구

Spray Synthesis of Photonic Crystal Based Automotive Coatings with Bright and Angular‐Dependent Structural Colors

AbstractIt is a challenge to prepare photonic crystal (PC) automotive coatings via spraying colloidal solutions because the fast fabrication tends to produce amorphous photonic crystals with faint colors. Here, a two‐step spraying process followed by thermal curing is developed to prepare waterproof PC coatings with bright, uniform, and angular‐dependent structural colors. The solvents in PC paint are studied to achieve a quick formation of liquid PC intermediate, which transformed into a highly crystalline PC coating. Thanks to the narrow and intense reflections, the as‐made coatings present colors with high saturation, including the red/yellow/green/blue colors achieved by tuning the particle size, and many spectral/non‐spectral colors via the mixing of base colors. Meanwhile, patterned or fully covered PC coatings with good chemical and mechanical stability can be prepared on different substrates, where the shiny colors changing with the viewing angles or the surface curvatures offer a new choice for personalized automotive coatings.

Characteristics of Volatile Organic Compounds in Wood Coatings and Automotive Coatings in China

Presently, there are a few studies on the measurement of industrial organic solvents in China. To determine the content and species of volatile organic compounds (VOCs) in industrial organic solvents and to provide the emission factors of organic solvents, the Chinese wood and automotive coatings, which accounted for the largest proportion of production in the world, were investigated. Coating samples were obtained by sampling from companies and buying from markets, and were measured in accordance with the domestic standard testing methods for coatings. The content and composition spectrum of VOCs in the coatings were determined, and the ozone formation potential (OFP) was then calculated. The results showed that for wood coatings, the average content of the VOCs in solvent-based, water-based, and ultra-violet (UV) coatings were 37.28%, 9.88%, and 18.02%, respectively. For automotive coatings, the average content of the VOCs in water-based original equipment manufacturer (OEM) coating, solvent-based OEM coating, water-based refinishing coating, and solvent-based refinishing coating were 15.06%, 59.90%, 11.79%, and 54.50%, respectively. The content of the VOCs in different types of coatings varied substantially. The main components and OFP contributors were alcohols and ethers for water-based coatings, benzene series and esters for solvent-based coatings, and esters, alcohols, and ethers for UV coatings. The average value of the coating samples could meet the current mandatory national standards, but 12% of the solvent-based wood coating samples and 42% of the solvent-based OEM coating samples did not meet the standards. In addition, except for the benzene series of the water-based wood coatings, the contents of harmful substances in other coating samples were up to the standards.

Functional Modification of Borassus flabellifer Sheath Fibres Using Isocyanate

An active hydroxyl content of Borassus flabellifer leaf sheath fibers are measured by the isocyanate back titration method, catalytically reacted with 1, 6 – hexamethylene diisocyanate biuret trimer and 2, 4-toluene diisocyanate-trimethylolpropane adduct, which is being used as cross-linkers in most of the automotive and industrial polyurethane coatings. The functional modifications of the fibers are confirmed by NCO titration method and Fourier-transform Infrared Spectroscopy (FTIR). The resultant biochemical fiber is analyzed for the thermal property, and surface topography measurement is done by Scanning Electron Microscope (SEM) and Thermogravimetric analysis (TGA), respectively. Moreover, 1, 6 – hexamethylene diisocyanate biuret trimer (HDT) treated BFSF having higher thermal stability due to higher urethane to urea content and intermolecular hydrogen bonding.

PPG receives DOE funding for energy-saving automotive paints and coatings

PPG receives DOE funding for energy-saving automotive paints and coatings

Poly(butylene succinate) and graphene nanoplatelet–based sustainable functional nanocomposite materials: structure-properties relationship

Sustainable functional polymer nanocomposites from renewable resources are extremely promising materials that can provide the next-generation of lightweight, multifunctional materials for several applications including energy storage, automotive, construction, defense, aerospace, consumer products, biomedical and functional coatings to name few. There is limited information on the use of sustainable polymers and graphene nanoplatelets (GNs), as well as the combinations of these two can provide reduced water permeability or enhanced electrical conductivity and improved thermal properties, and so on. Building upon this hypothesis, biobased poly(butylene succinate)/few-layer GN nanocomposites were prepared via a solventless melt-blending technique. Different characterization techniques such as differential scanning calorimetery, thermogravimetric analysis, dynamic mechanical analysis, dielectric spectroscopy, X-ray diffraction (XRD) and hot stage optical microscopy were used to study the thermal and structural characteristics. The melt blending was characterized by torque and temperature curves which showed that torque was reduced by up to 15 Nm, and melt temperature was improved by up to 5 °C. The improved crystallization of the composites in low concentrations of GN was observed. Graphene has been found to increase the crystallization temperature up to 10 °C and yielded pronounced spherulite structure, whereas peak shift was observed in XRD. High filler loading from 0.5 to 6.0 wt% was used to obtain more insights for few-layer graphene applications for thermoplastic polymer processing applications.

Can Automotive Coatings Save the Market?

Can Automotive Coatings Save the Market?

Functional Modification of Borassus flabellifer Sheath Fibres Using Isocyanate

An active hydroxyl content of Borassus flabellifer leaf sheath fibers are measured by the isocyanate back titration method, catalytically reacted with 1, 6 – hexamethylene diisocyanate biuret trimer and 2, 4-toluene diisocyanate-trimethylolpropane adduct which is being used as cross-linkers in most of the automotive and industrial polyurethane coatings. The functional modifications of the fibers are confirmed by NCO titration method and Fourier-transform Infrared Spectroscopy (FTIR). The resultant biochemical fiber is analyzed for the thermal property, and surface topography measurement is done by Scanning Electron Microscope (SEM) and Thermogravimetric analysis (TGA), respectively. Moreover, 1, 6 – hexamethylene diisocyanate biuret trimer (HDT) treated BFSF having higher thermal stability due to higher urethane to urea content and intermolecular hydrogen bonding.

World demand for automotive coatings exceeds 3 M tonnes

World demand for automotive coatings exceeds 3 M tonnes

Texture Evaluation of Automotive Coatings by Means of a Gonio-Hyperspectral Imaging System Based on Light-Emitting Diodes

Sparkle and graininess are textural effects that appear as intrinsic spatial features of coatings containing goniochromatic pigments, whereas others such as mottling are undesired outcomes. In this study, we present new methods for the evaluation of sparkle, graininess and mottling of automotive coatings through images acquired with a novel gonio-hyperspectral imaging system based on light-emitting diodes with extended spectral sensitivity beyond the visible range (368–1309 nm). A novel analysis of sparkle that considered the amount of sparkling spots was used. Graininess was quantified through a novel statistical descriptor based on the energy descriptor computed from the histogram. A new index was proposed for an enhanced detection of mottling based on the analysis of striping, which was better observed and quantified in the infrared range. Spectral assessments showed a strong relationship with color and spectral reflectance for graininess and mottling. In conclusion, the results showed that these new spatial and spectral methods are a suitable, alternative and potential approach for the assessment of these textural features.