Preparation and Performance of Thermochromic and Self-Repairing Dual Function Paint Film with Lac Resin Microcapsules and Fluorane Microcapsules.

Xiaoxing Yan,Lin Wang,Wenting Zhao

doi:10.3390/polym13183109

Abstract

Microcapsules with lac resin as the core material and urea-formaldehyde resin as the wall material were prepared by in situ polymerization, and then the lac resin microcapsules and fluorane microcapsules were added into a water-based primer or topcoat, respectively, to prepare water-based coatings with dual functions of thermochromic and self-repair. The effects of different methods of adding microcapsules on the optical properties, mechanical properties, self-repairing properties, and the aging resistance of water-based paint film were investigated, so as to prepare water-based paint film with the best discoloration and self-repairing functions. The results showed that the paint film with 10.0% fluorane microcapsules in the topcoat and 5.0% lac resin microcapsules in the primer had better comprehensive properties, and the paint film changed from yellow to colorless at 32 °C, with a color difference of 68.9, hardness of 3H, adhesion grade of 0, impact resistance of 13.0 kg∙cm, and elongation at break of 20.0%. The resistance of the paint film to NaCl, ethanol, and detergent was grade 2, with slight discontinuous marks, and the resistance to red ink was grade 3, with slight marks. The lac resin microcapsules have good aging resistance, which can enhance the aging resistance of the paint film with fluorane microcapsules. The gap width of the paint film was repaired by 2.1 µm, the self-repairing rate was 12.3%, and the paint film with lac resin microcapsules had a better crack inhibition effect. The results have provided a reference for multifunctional wood coatings.

Highlights

As a natural polymer composite material, wood material has a unique vein, color, and texture and is the main material for furniture [1,2,3]
The absorption peaks at 3355 cm−1 and 2966 cm−1 were due to the tensile vibration of N-H and C-H, and the absorption peaks at 1638 cm−1 and 1560 cm−1 were due to the tensile vibration of C=O and C-N
An orthogonal experiment showed that the way of adding fluorane microcapsules was the primary factor affecting the color difference of paint film, and the color change temperature of the paint film was 32 °C

Summary

Introduction

As a natural polymer composite material, wood material has a unique vein, color, and texture and is the main material for furniture [1,2,3]. Coatings on the furniture surface can effectively improve the dry shrinkage and wet swelling of wood and play a further role in aesthetics and protection [4,5,6,7]. Lac is a natural product which is nontoxic and environmentally friendly, has a good film-forming property, is fast drying and curing, and has unique solubility and excellent thermal properties [8]. Long et al [12] used calcium shellac (CS) as a matrix to encapsulate polymerized melamine formaldehyde microcapsules or CaCO3 nanoparticle-stabilized microcapsules to prepare composite microcapsules with enhanced mechanical stability and reduced active ingredient leakage. The mechanical stability of composite microcapsules was improved, and the leakage of active ingredients was reduced by an order of magnitude. There were few studies using lac as the core material for self-repairing microcapsules

Methods

Results

Conclusion