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Pendulum hardness of polyurethane coatings during curing

Zhifeng Huang (Department of Applied Chemistry, Xi’an Jiaotong University, Xi’an, China)
Xiaoyang Ma (Department of Applied Chemistry, Xi’an Jiaotong University, Xi’an, China)
Zemin Qiao (Department of Applied Chemistry, Xi’an Jiaotong University, Xi’an, China)
Shujuan Wang (Department of Applied Chemistry, Xi’an Jiaotong University, Xi’an, China)
Xinli Jing (Department of Applied Chemistry, Xi’an Jiaotong University, Xi’an, China)

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 26 August 2014

Abstract

Purpose

This paper aims to disclose the evolution of pendulum hardness of two-component acrylic polyurethane coatings during the cure process and attempts to describe the quantitative relationship between pendulum hardness and curing time. These findings are helpful for the study of fast curing acrylic polyurethane coatings.

Design/methodology/approach

The pendulum hardness method was used to monitor the hardness of two-component acrylic polyurethane coatings during curing. The quantitative relationship between pendulum hardness and curing time can be obtained with Avrami equation.

Findings

The evolution of coating pendulum hardness can be divided into three stages. By using the Avrami equation that explained the influence of both the acid value and the curing temperature on the drying speed of hydroxyl acrylic resin, the evolution of coating pendulum hardness during curing can also be accurately described.

Research limitations/implications

It should be noted that the physical meaning of the Avrami exponent, n, is not yet clear.

Practical implications

The results are of great significance for the development of fast-curing hydroxyl-functional acrylic resins, with the potential to improve the drying speed of the coatings used in automotive refinish.

Originality/value

It is novel to divide the pendulum hardness into three stages, and, for the first time, the Avrami equation is utilized to describe the evolution of coating pendulum hardness during curing.

Keywords

Citation

Huang, Z., Ma, X., Qiao, Z., Wang, S. and Jing, X. (2014), "Pendulum hardness of polyurethane coatings during curing", Pigment & Resin Technology, Vol. 43 No. 5, pp. 271-276. https://doi.org/10.1108/PRT-11-2012-0032

Publisher

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Emerald Group Publishing Limited

Copyright © 2014, Emerald Group Publishing Limited