https://doi.org/10.15255/KUI.2020.072
Published: Kem. Ind. 70 (9-10) (2021) 489–499
Paper reference number: KUI-72/2020
Paper type: Original scientific paper
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Influence of Thermoplastic Polyolefins Flame Treatment on Coating Adhesion in Industrial Conditions of Robotic Dyeing

V. Merzel, S. Lučić Blagojević, Z. Buhin Šturlić, M. Meheš and M. Leskovac

Abstract

In this paper, the influence of flame treatment on the surface properties of polypropylene (PP) and thermoplastic polyolefins with talc and carbon black filler (TPO), and adhesion of the applied coating in the conditions of industrial robotic dyeing process were investigated. The flame treatment was carried out at two distances from the flame (7.5 cm and 12.5 cm) at constant air and methane flows as well as speed of the burner. The thermal stability of untreated samples was investigated using thermogravimetric analysis (TGA). The change in thermal properties before and after flame treatment was investigated using differential scanning calorimetry (DSC). Changes of the samples’ surface energy were examined before flame treatment, 1 h and 24 h after flame treatment, by the contact angle method. Qualitative analysis of the surface chemical composition, before and after flame treatment, was performed by ATR – FTIR analysis, and morphological changes by scanning electron microscopy (SEM). After applying the base layer, dye and topcoat on the surface of the treated samples, the adhesion was determined by standard methods ISO 2409 and ISO 16925/D25 2018-B. The results showed that TPO containing talc and carbon black filler have better thermal stability compared to PP. Flame treatment influenced the surface characteristics of the samples, namely the increase in surface free energy and the appearance/structure of the surface. With ATR – FTIR, the existence of polar groups on the surface after flame treatment were determined. According to the standards, all dyed samples met the requirements of excellent adhesion on the substrate/coating interface.

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Keywords

polypropylene, thermoplastic polyolefins, flame treatment, surface free energy, coating, adhesion