D2.1 - Bio-based Thermoplastic Powder Coating

Funded by the European Union under the Grant Agreement 101091464. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Health and Digital Executive Agency (HaDEA). Neither the European Union nor the granting authority can be held responsible for them. Sustainable surface protection by glass-like hybrid and biomaterials coatings Deliverable D.2.1 Bio-based thermoplastic powder coating Deliverable Information Responsible partner: WOODKPLUS Work package No and Title: WP2 - SSbD-driven R&I of 3 novel Coating Materials, and demonstration of industrial assay Contributing partner(s): SIKEMIA Dissemination level1: PU Type: DEMO Due date: 30/06/25 Submission date: 01/07/25 Version: Version 3 1 PU = PUBLIC fully open ((warning) automatically posted online on the Project Results platforms) SEN = Sensitive — limited under the conditions of the Grant Agreement EUCl = EU classified under Decision 2015/444 2 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating Project Profile Programme Horizon Europe Call HORIZON-CL4-2022-RESILIENCE-01 Topic HORIZON-CL4-2022-RESILIENCE-01-23: Safe and sustainable by design chemicals and materials (RIA) Number 101091464 Acronym BIO-SUSHY Name Sustainable surface protection by glass-like hybrid and biomaterials coatings Start Date 1 January 2023 Duration 48 months Type of action HORIZON Research and Innovation Actions Granting authority European Health and Digital Executive Agency Project Coordinator MATERIA NOVA Document History Version Date Entity Remarks Version 1 (not shared) 11/06/2025 Wood K plus Written by Ivana Burzic Version 2 (shared) 18/06/2025 Wood K plus Written by Ivana Burzic; shared for review Version 3 (final) 23/06/2025 Wood k plus Written by Ivana Burzic/Christoph Jocham 3 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating Publishable Summary The Deliverable D.2.1 “Bio-based thermoplastic powder coating” is presented in this document and aims summarizing the developed organic powder coating formulations covering their production as well as applications on the selected paper substrates. The document is organized into different sections: 1) Task objectives 2) Description of powder coating formulation preparation, characterization and application 3) Toxicity Measurements and related results 4) Conclusions 4 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating Table of Contents Publishable Summary .................................................................................................................................. 3 List of Figures ................................................................................................................................................ 5 List of Tables ................................................................................................................................................. 6 Table of Abbreviations ................................................................................................................................. 6 1. Objectives .............................................................................................................................................. 7 2. Description ............................................................................................................................................ 8 2.1. General characteristics of the demonstrator ............................................................................. 8 2.2. Physico-chemical characteristics of the organic powder coating material .......................... 13 3. Toxicity testing of coating components ........................................................................................... 15 4. Conclusions ........................................................................................................................................ 18 5 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating List of Figures Figure 1: DEMONSTRATOR 1: PHA Type 1 powder coating (= virgin PHA powder with additives) packed in a plastic bag (size:11x18cm) (left) and powder spray coated paper substrate (right; size 8x12cm) ......................................................................................................................................................... 8 Figure 2: DEMONSTRATOR 2: Lignin Type 1 powder coating = Modified Lignin powder (Hydrophobic Lignin with n-octyltiethoxysilane modification done by Sikemia) packed in a plastic bag (size:11x18cm) (left) and powder spray coated paper substrate (right; size 8x12cm) ........................... 8 Figure 3: DEMONSTRATOR 3: PBS Type1/ Lignin Type2 powder coating (= PBS based formulations with Lignin Type 2) packed in plastic bags (size:11x18cm) (high lignin content); prepared granulate (left), powder coating (after grinding; middle) and coated paper (right; size: 8x12cm) ......................... 9 Figure 4: Twin screw extrusion (melt compounding) of thermoplastic powder coatings at Wood K plus, extruder shown starting from left followed by prepared granulates ............................................. 9 Figure 5: Granluates grinded to powders by centrifugal mill (left) and further sieved (middle); Right: granulates before grinding and sieving as well in final powder form .................................................. 10 Figure 6: Functionalization of Lignin with C8 Silane grafting function (n-octyltriethoxysilane) .......... 10 Figure 7: Powder coating experiments set up ........................................................................................ 11 Figure 8: Coated selected paper substrate with PHA Type 1 ................................................................. 12 Figure 9: Coated paper substrate with Modified lignin by SIKEMIA (Lignin Type 2) ............................ 12 Figure 10: Coated selected paper substrate with PBS Type1/Lignin Type 2 powder coating ............ 12 Figure 11 Particle size distribution of PHA (left) and PBS powder (right) using sieve analysis ........... 13 Figure 12: Light microscopy micrographs showing different sieve fractions (particle sizes) after PHA powder sieve analysis ............................................................................................................................... 13 Figure 13: Light microscopy micrographs showing different sieve fractions (particle sizes) after PBS powder sieve analysis ............................................................................................................................... 14 Figure 14: Scanning Electron Microscopy (SEM) micrographs form paper substrates (left, 100µm scale), PBS based powder coated paper (middle, 100µm scale) and PHA based coated paper (right, 100 µm scale) ............................................................................................................................................. 14 Figure 15: Photos of tests carried out on coated samples (from left to right): contact angle measurements; KIT; Gurley; water repellency. ....................................................................................... 15 Figure 16 Cell viability by MTT assay studied at ITENE ........................................................................... 16 Figure 17: Toxicological results of the Lignin C8 modified by SIKEMIA (Lignin Type1) ........................ 17 Figure 18: (a) RCV scan of lipid layer sensor in the absence (black) and in the presence of 0.009 % modified lignin (red) in the phosphate buffered saline at 40 Vs-1; (b) Percentage peak suppression in the presence of coating material carnauba wax (CW), PBS (PBS Type1), PHBV (PHA Type1) and modified lignin (Lignin Type1) at concentrations displayed on the bar graph; (c) from leachates arising from coated papers in phosphate buffer saline at 20 °C (yellow) and 70 °C (green) .............. 17 6 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating List of Tables Table 1: BIO-SUSHY organic powder coatings main characteristics ........................................................ 7 Table 2: Methoxyl Group Determination results done at Wood K plus ................................................ 11 Table 3: Results covering contact angle measurements, KIT rating, Gurley measurements, Cobb Test, Water repellency covering different powder coating formulations ............................................. 15 Table 4: Toxicological studies (cytotoxicity) results covering tested PHA type (PHA Type1), PBS (PBS Type 1) and modified lignin by SIKEMIA within BIO-SUSHY project ...................................................... 16 Table of Abbreviations Abbreviation Definition FTIR Fourier Transform Infrared Spectroscopy MeOH Methanol PBS Polybutylene succinate PHA Polyhydroxyalkanoates PHBV Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) SEM Scanning Electron Microscopy SSbD Safety and Sustainability by Design UWG Under Water Granulate System 7 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating 1. Objectives This deliverable covers the production of organic powder coating materials, 150g per different formulation, developed within BIO-SUSHY project under task WP2 Task 2.1 (main characteristics defined in Table 1). The prepared powder coatings are being characterized in respect to their physicochemical properties as shown in the paragraphs below. Further, coated paper substrates are characterized in respect to their previously identified Key Performance Indicators. Table 1: BIO-SUSHY organic powder coatings main characteristics BIO-SUSHY Coating materials % biobased Ratio inorganic/organic Solvent Application process Biobased powder coating (Wood K plus) formulation content: >80% 90-100% organic 0% (powder coating) Powder spray; Gelling temperatures: 80 to max. 200 °C; Gelling time: 5 to 30 sec. 8 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating 2. Description 2.1. General characteristics of the demonstrator In this section the preparation and characterization of the demonstrators carried out by WOOD K PLUS in collaboration with SIKEMIA is shown in more detail, covering the production method of 150g powder coating material, for different formulations. Based on the results shown and discussed in the following paragraphs are shown the 3 different pictures of the best-performing powder coating formulations (see figures Figure 1, Figure 2, Figure 3) . The demonstrators cover PHA Type 1 powder coating (Figure 1), Lignin Type 1 powder coating modified by SIKEMIA (Figure 2), and PBS Type1 based formulation with high Lignin Type 2 content (Figure 3). Figure 1: DEMONSTRATOR 1: PHA Type 1 powder coating (= virgin PHA powder with additives) packed in a plastic bag (size:11x18cm) (left) and powder spray coated paper substrate (right; size 8x12cm) Figure 2: DEMONSTRATOR 2: Lignin Type 1 powder coating = Modified Lignin powder (Hydrophobic Lignin with noctyltiethoxysilane modification done by Sikemia) packed in a plastic bag (size:11x18cm) (left) and powder spray coated paper substrate (right; size 8x12cm) 9 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating Figure 3: DEMONSTRATOR 3: PBS Type1/ Lignin Type2 powder coating (= PBS based formulations with Lignin Type 2) packed in plastic bags (size:11x18cm) (high lignin content); prepared granulate (left), powder coating (after grinding; middle) and coated paper (right; size: 8x12cm) 2.1.1: Organic powder coatings manufacturing For the production of different thermoplastic powder coatings under Task 2.1 the following procedure has been used. Thermoplastic powder coatings made of thermoplastic resins like different types of PHA and PBS biopolymers are combined with additives - plasticizers, temperature stabilizers and natural polymers different lignin types (in this report shown under following names Lignin Type 1 (modified by SIKEMIA within the project), Lignin Type 2 (available at pre-commercial scale)) considering different blending ratios using gravimetric dosing and extruded using laboratory scale twin screw extruder Brabender TSE20 (20 mm in screw diameter). The extruded material was pelletized using an Under Water Granulating (UWG) System as shown below in Figure 4. Produced granulates are further crushed using grinder and screened to gain powder (see Figure 5) of prepared coatings targeting a specific particle size distribution up to 150 µm in diameter. Powder coating is a 100% solids content applied as a dry powder (after grinding) and subsequently formed into a film with heat using a laboratory press machine (illustration is given in Figure 7). Figure 4: Twin screw extrusion (melt compounding) of thermoplastic powder coatings at Wood K plus, extruder shown starting from left followed by prepared granulates 16 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating coatings to ensure safety from an early R&D coating design phase. Table 4 displays the cytotoxicity results from PHA (PHA Type 1), PBS (PBS Type1) and Modified lignin (Lignin Type 2) studied here. Figure 17 shows the cell viability by MTT assay from tested modified lignin. For other tested materials the results are shown only within Table 4. Figure 16 Cell viability by MTT assay studied at ITENE Table 4: Toxicological studies (cytotoxicity) results covering tested PHA type (PHA Type1), PBS (PBS Type 1) and modified lignin by SIKEMIA within BIO-SUSHY project 17 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating Figure 17: Toxicological results of the Lignin C8 modified by SIKEMIA (Lignin Type1) Further, for step 3, to experimentally assess the risk of BIO-SUSHY coatings materials when it comes to the use phase, a biomembrane sensor coupled with a minirelease accelerator within an online configuration at University Leeds is being used to measure potential. Figure 18: (a) RCV scan of lipid layer sensor in the absence (black) and in the presence of 0.009 % modified lignin (red) in the phosphate buffered saline at 40 Vs-1; (b) Percentage peak suppression in the presence of coating material carnauba wax (CW), PBS (PBS Type1), PHBV (PHA Type1) and modified lignin (Lignin Type1) at concentrations displayed on the bar graph; (c) from leachates arising from coated papers in phosphate buffer saline at 20 °C (yellow) and 70 °C (green) The results displayed in Figure 18 showed that compared to the control test no evidence of the significant release from the different studied coatings based on modified lignin, PBS and PHA thermoplastic matrices is observed. Still, some differences in the biomembrane activity between different coated papers are recognized. 18 of 18 Sustainable surface protection by glass-like hybrid and biomaterials coatings D.2.1:Bio-based thermoplastic powder coating 4. Conclusions Different thermoplastic powder coating formulations have been developed to potentially replace PFAS compounds used in paper coating targeting water and oil repellency (grease resistance). The paper samples coated with PBS/lignin and PHA based formulations by spray exhibit hydrophobic properties (as shown in water absorption tests, with some promising results for Cobb tests) and very good results for KIT rating (grease resistance) without the use of PFAS. Bio-based content of different thermoplastic powder coatings presented here may vary from 80-90% for PBS based coatings with lignin (lignin loadings from 30-40 weight percentage loading and having PBS as matrix polymer with 50 % bio-based content). Further, formulations based on PHA are up to 98% bio-based (2 weight percent of additives inside). The certification on bio-based content of different PHA types used here are available as an official document from PHA producers. Regarding the use of natural polymers, such as different lignin types being used in some powder coating formulations as additives, a full toxicity assessment is being conducted following the SSbD Framework. The powder coatings should be applied on one side of the paper. The storage conditions recommended are dry storage at <25°C, up to 2 years. Since the powder coatings studied here are targeting food packaging applications, migration tests, compostability and repulping (recycling) are planned to be covered following current regulations for the paper and packaging sector. In addition, during the upcoming scale-up phase of the BIO-SUSHY coating formulations the selected thermoplastic powder coating formulations will be tested with respect to their processability, focusing on extrusion coating and/or dry powder coating technologies of paper.