Effect of Shellac-Bamboo Blend on Paint Properties

Abstract

The paints industry holds significant economic importance within the chemical sector. Construction paints represent a substantial portion of paint industry production by volume. Rising paint awareness, increased paint consumption driven by thermal insulation systems, and emphasis on aesthetics are driving growth in paint applications and competition in the paint market.

This study involved optimization work on paint formulations for construction applications by adding a bamboo-shellac mixture and additives, with high quality as the primary consideration. The effects of bamboo's moisture-blocking, air permeability and antibacterial properties on paint were examined. Shellac's ability to provide good homogenization and its gloss properties were taken into account in efforts to improve the physical characteristics of the paint. As a result, the properties of the formulated paint were enhanced and it was determined that the paint could be applied in various areas of the construction sector.

1. Introduction

Turkish paint industry, which began with and continues to maintain external dependency regarding raw material requirements, has proceeded in the form of multifaceted integration with the outside world under the influence of globalization trends in recent years [1]. Technological advancement has affected the paint market. Paint manufacturers have worked toward increasing paint quality. Along with growing demand, environmentally friendly, odorless paints resistant to dust and water have begun to be produced. Paint is used in many sectors for numerous purposes, primarily decorative. Today, paint holds a very important position in the construction sector, which has a high share in production. The construction sector prioritizes high performance in all its products due to increasing competition. Shellac is a natural resinous refined product secreted by the parasitic insect Kerria lacca on various host trees in India, Thailand and Myanmar. It offers glossy properties, protects against chemical reactions and mechanical wear. Shellac is an environmentally friendly and biodegradable polymer. Shellac is also used in pharmaceuticals due to its excellent film-forming and acid-resistance properties [2,3]. Bamboo, regarding its structural properties, has recently become an important research topic. Bamboo has attracted human interest over centuries and numerous publications have been made on this subject. It is used as a primary construction material throughout Southeast Asia and Japan [4-6]. In this study, optimization studies using the Taguchi method and paint tests performed by adding bamboo, shellac and additives to paint for use in the construction sector led to the conclusion that the physical properties of paint could be improved.

2. Experimental Work

Additives with different properties at levels between 0-6% (w/w) were added to a predetermined amount of water-based paint diluted with a certain amount of water. The experiment consisted of a set containing 16 different paint formulations. In the set, the quantities of additive materials to be added were determined using the Taguchi Optimization Method with 4 parameters at 4 levels. For the set, bamboo, shellac and additives were determined using the water-based Taguchi Optimization Method. For the set, bamboo, shellac and additives were added to water-based paint at different mass percentages. The resulting mixtures were stirred at 1000 rpm for 3 minutes. Based on the Taguchi method, 16 different paint formulations were prepared according to additives at different ratios. The prepared paints were applied to specially prepared aluminum plates measuring 10x10 cm² with a film thickness of 200 μm using an applicator and left to dry. The prepared paints and plates after drying are shown in Figure 2.1.

Figure 2.1 Prepared paints and plates after drying

Before conducting analyses to determine the surface properties of paints applied to the plates, viscosity measurements were performed on paint mixtures using a viscometer to be used as output in the Taguchi Optimization Method to identify paints with optimum properties. After viscosity measurements were performed on 16 paint samples containing different materials, the optimum sample was identified. 3. Results and Discussion

3.1. Taguchi Method Results

In this study, the L-16 orthogonal array was used from the different orthogonal arrays created by the Taguchi Method to explain numerous experimental conditions. The decision to use this array was made considering that 4 parameters could be evaluated for 4 different levels. Normally, according to the full factorial approach, 44=256 paint formulations would need to be prepared for each experimental set; however, with the aid of orthogonal arrays, this number was reduced to 16. The L-16 orthogonal array used for experimental analysis and viscosity values used as output in the analysis along with results of some tests are shown in Table 3.1. In Table 3.1, the parameters are determined as Shellac, Additive 1 (A1), Bamboo and Additive 2 (A2) in sequence. The values expressed by the numbers 1, 2, 3 and 4 in the orthogonal array represent the levels of experimental parameters and vary in the range of 0-6% by mass. In the analysis performed with Minitab software using the Taguchi optimization method, viscosity measurement values were used while identifying paint formulations with optimum properties in the experimental sets. Considering the applicability of paints to surfaces and their flowability, the "nominal is best" characteristic was used and average value graphs and S/N (signal-to-noise) analysis graph shown in Figure 3.1 were obtained.

Figure 3.1 S/N (signal-to-noise) analysis

In the analysis performed according to the "nominal is best" characteristic, at which level each parameter reached the smallest value was examined. Based on this, it was determined that paint sample number 15 had optimum properties.

3.2. Contact Angle Analysis Results

In recent years, there is increasing interest in superhydrophobic surface studies due to potential applications such as self-cleaning, nanofluids and electroplating. Wettability studies typically include measurement of contact angles as primary data showing the degree of wetting when a solid and liquid interact. Small contact angles (<90°) correspond to high wettability, while large contact angles (>90°) correspond to low wettability [7]. As a result of contact angle analysis, the average hydrophobicity value of water-based paint increased from 53.12° to 105.87° (Figure 3.2). This demonstrated with measurement results that bamboo increased hydrophobicity properties.

Figure 3.2 Contact angle measurement result of paint with improved properties

3.3 SEM Results

The morphological and structural properties of the paints were examined using SEM (Scanning Electron Microscopy) analysis. In SEM analysis, samples were magnified 10,000 times and differences in surface properties were examined and compared with literature [8]. When SEM analysis results were compared, the additive-containing water-based paint was observed to have a much better surface and homogeneous appearance compared to the reference paint. The added additives were observed to reduce moisture permeability and improve the properties of water-based paint (Figure 3.3).

Figure 3.3 SEM analysis results: (a) Reference paint, (b) Optimum paint

4. Conclusion

As a result of analyses applied to optimum and reference paints determined by the Taguchi Method in this study, improvement was observed in the hydrophobicity properties of water-based paint. Furthermore, improvement in the surface coverage and adhesion properties of water-based paint was evident from SEM photographs. It is considered that this paint with improved properties could be utilized in the construction sector.   Associate Professor Nil Acaralı Department of Chemical Engineering Yıldız Technical University       Chemical Engineer Sibel Demir Department of Chemical Engineering Yıldız Technical University     References [1] Tunçgenç M., (2015), Turkish Paint Industry, Izmir. [2] Farag Y. and Leopold C. S., (2009), Physicochemical Properties of Various Shellac Types, Dissolution Technologies, dx.doi.org/ 10.14227/DT160209P33. [3] Coelho C., Nanabala R., Ménager M. and Commereuc S., (2012), Molecular Changes During Natural Biopolymer Ageing-The Case of Shellac, Polymer Degradation and Stability, 97, 936-940. [4] Arce O. A., (1993), Fundamentals of the Design of Bamboo Structures, Thesis, Technical University Eindhoven, DOI: 10.6100/ IR402687. [5] Janssen J. J. A., (2000), Designing and Building with Bamboo, Technical Report, No:20, Technical University of Eindhoven Eindhoven, The Netherlands. [6] Bystriakova N., Kapos V. and Lysenko I., (2004), Bamboo Biodiversity, Citation: UNEP-WCMC/INBAR. [7] Yuan, Y. and Lee, T.R. (2013), Contact Angle and Wetting Properties. In: Bracco, G. and Holst, B., Eds., Surface Science Techniques Springer Series, Surface Sciences, Vol:51, Springer Berlin Heidelberg, Berlin and Heidelberg, 3-34, DOI 10.1007/ 978-3-642-34243-1_1. [8] Kapakin K. A., (2006), Scanning Electron Microscopy, YYÜ Vet. Fac. J., 17(1-2):55-58.