CAN AND COIL COATINGS A SUSTAINABLE APPROACH TO MODERN COATING TECHNOLOGY

Transcription

1 A SUSTAINABLE APPROACH TO MODERN COATING TECHNOLOGY CAN AND COIL COATINGS

2 A Sustainable Approach to Modern Coating Technology Patcham FZC is a well-established manufacturer of specialty additives headquartered in the United Arab Emirates. Since its inception, Patcham has steadily grown into a leading supplier of specialty additives for the Paint & Coatings, Ink, PVC and Composite industries. The company s Pat-Add range of coating additives includes wetting & dispersing agents, defoamers, slip & leveling agents, rheology modifiers. Whilst keeping focus on environmental sustainability, the company produces products using green raw materials that are APEO free and have low or no VOC. These products are multi functional and multi compatible, which simplifies the production process, reduces the chance of errors and minimizes inventory thus improving cost effectiveness. Patcham has built a strong manufacturing and R&D infrastructure that enables the rapid transition from concept to products. The company has strategically located technical service laboratories, offices and representatives around the world to provide the most efficient customer service. In addition, a well-developed robust supply chain network enables it to deliver its products and services to customers around the globe with minimal lead-time.

3 Contents Introduction Patcham additive package Primers and backcoats Topcoats Black topcoat Red topcoat Blue topcoat

4 Introduction Coil coating is a continuous, automated process for coating metal before fabrication into end products. A steel or aluminum substrate is delivered in coils from the rolling mills. The metal coil is positioned at the beginning of the coating line and in one continuous process, the coil is unwound, cleaned, treated, primed and painted before being coiled at the other end and packaged for shipment to other industries to be fabricated into variety of end products. All of this happens at up to 700 feet per minute! The excellent top coat finishes in these coatings are directly influenced by the resins, pigments and the additives used. Innovative additives from Patcham, designed to work with pigments in various resins deliver the attributes necessary for the required topcoat performance. Entrance accumulator Prime coater Curing oven Dry Exit accumulator Uncoiler Pretreatment (Cleaning and conversion coating) Top coater Finish oven Water quench Cut-off Source: NCCA Figure 1: Typical coil coating line The following steps take place on a modern coating line: 01. Stitching the strip to the previous coil 02. Cleaning the strip 03. Power brushing 04. Pre-treating with chemicals 05. Drying the strip 06. Applying primer on one or both sides 07. Curing (often only 15 to 60 seconds) 08. Cooling the strip 09. Top coating on one or both sides 10. Second curing 11. Cooling down to room temperature 12. Rewinding of the coated coil 1

5 Patcham additive package Table 1: Patcham additives for coil coatings Type of coating Additive Grade Dosage(%) Top Coat Polyester : Melamine Dispersing additive Pat Add DA 947 High Molar Volume polymeric dispersing agent On SOP White pigment : 1-5 Low structured carbon black : 30 to 50 High structured carbon black : 50 to 120 Inorganic pigments : Organic blue/green : Organic red/violet/yellow : Grinding stage Primer Polyester : Melamine : Epoxy Dispersing additive Pat Add DA 1801 Polyester anionic wetting and dispersing agents On SOP 1-5 (Inorganic and extenders) Grinding stage Top coat and primer Polyester : Melamine Defoamer Pat Add AF 70 Best for defoaming in solvent free high build coatings 0.1 to 0.3 (On total formulation) Letdown stage Top coat and primer Polyester : Melamine Defoamer Pat Add AF 62 Silicone and fluoro free polymeric defoamer 0.1 to 0.3 (On total formulation) Letdown stage Top coat Polyester : Melamine Surface modifier Pat Add LE 1070 Solvent free, fluoro and silicone free polyester surface modifier 0.2 to 0.5 (On total formulation) Letdown stage Figure 2: The painting system Figure 3a: Adhesion test Figure 3b: Pencil hardness test NB: Adhesion test is done as per ASTM D (tape test) and the pencil hardness test is done as per ASTM D

6 Patcham additive package - Primers and backcoats Wetting and dispersing additives Primers and backcoats The main role of primers is to provide good adhesion of the topcoat to the pre-treated substrate. Primers have a crucial role in protecting the substrate from corrosion. Furthermore, primers are expected to be compatible with subsequent layers of coatings. Backcoats on the other hand, have a dual function. They are formulated to have properties of both the topcoat and a primer. Back coats are applied on the reverse of the metal sheet. Pat-Add DA 1801 An additive for dispersion of inorganic pigments, extenders and matting agents An anionic polyester additive, where substrate adhesion is not affected due to its chemical nature The optimum benefit of the additive is to provide reduction of settling of pigment and extenders, thus preventing syneresis It is recommended for resin systems i.e., epoxy, alkyd, HMMM, PU Figure 4: Application of primers 3

7 Patcham additive package - Primers and backcoats Table 2: Guide formulation of Pat-Add DA 1801 for coil coat primers/backcoats Raw materials Weight (%) Raw materials Weight (%) Millbase Letdown Saturated polyester Melamine formaldehyde Pat-Add DA Saturated polyester Titanium dioxide Epoxy resin 4.00 Barytes 5.50 Solvesso Zinc phosphate 8.00 Acid catalyst 0.60 Talc Total Fumed silica 0.30 Solvesso SOP dispersant Resin ratio (PE:MM) Peak metal temperature Bar coater 1.50% 60: C 10µm Figure 5: Coil coating primer actual paint sample Table 3: Viscosity and stability Stability study Initial viscosity, cp Viscosity after storage, 500C x 1 month, cp Settling Pat-Add DA No settling observed 4

8 Patcham additive package - Topcoats The ultimate goal of the multi step coil coating processes is to provide a fast, durable, cost effective and a sustainable product with an exceptional topcoat finish to meet the approval of the end use product manufacturers. The top coat is often required to be glossy or matt, colored, flexible, particularly UV-resistant or have a combination of many different functions. The additives highlighted below have been designed to work with the pigments and resins to provide the desired topcoat finish Pat-Add DA 947 High Molar Volume technology polymeric dispersant for solvent-based industrial coatings Enhances color strength and hue of pigment in paints and pigment concentrates Equally charges pigments to prevent possible co-flocculation in cross-tinting of paints Improves wetting and prevents thixotrophy Highly recommended for acid-catalyzed polyester/melamine topcoats and PVDF systems such as coil coatings, automotive finishes and general industrial coatings Pat-Add LE 1070 Silicone and fluoro-free surface modifier Most efficient levelling agent in solventborne systems, notably industrial coatings, including stoving enamels and can coatings Unlike most polysiloxane based levelling agents, Pat-Add LE 1070 does not affect surface slip or intercoat adhesion Additive is allowed to be used in main coating and ink formulations for food contact applications Pat-Add AF 62 Efficient silicone free defoamer for solventborne coatings Recommended for clear system resin system i.e., 2K PU, TPA, Epoxy and saturated polyester Suitable for various application procedures, such as brushing, airless spraying, roller and curtain coating 5

9 Patcham additive package - Black topcoat Table 4: Guide formulation for black topcoat Raw materials Weight (%) Mill base Saturated polyester Pat-Add DA 947 Black pigment Solvesso 150 Fumed silica Letdown Saturated polyester Melamine formaldehyde Pat-Add LE 1070 Pat-Add AF 62 Acid catalyst Solvesso 150 Total SOP dispersant Resin ratio (PE:MM) Peak metal temperature Bar coater DFT of primer % 60: C 36µm 5µm Figure 6: Saturated polyester : melamine formaldehyde coil coating system CIE lab measurement Gloss value Color Values DA 947 Ref A Ref B DA 947 Ref A Ref B Initial After stability 0 DA 947 Ref A Ref B DA 947 Ref A Ref B L * Initial After stability b * o o Gloss values 20 Gloss values 60 Gloss Values Figure 7 : Colour values of black topcoat Figure 8: Gloss values of black topcoat 6

10 Patcham additive package - Red topcoat Table 5 : Starting formulation coil coating red topcoat Raw materials Weight (%) Mill base Saturated polyester Pat-Add DA 947 Pigment red 254 Solvesso 150 Letdown Saturated polyester Melamine formaldehyde Pat-Add LE Pat-Add AF Acid catalyst 0.50 Solvesso Total SOP dispersant Resin ratio (PE:MM) 45.00% 60:40 Figure 9: Saturated polyester : melamine formaldehyde coil coating system Peak metal temperature 2320 C Bar coater #36 DFT of primer 5µm 56.5 CIE lab measurement Gloss values a* values ΔE Gloss values DA 947 Ref A Ref B 0 0 DA 947 Ref A Ref B Initial a* Rub out test, de o Gloss Value 20 Gloss value 60 o Figure 10: Colour values of red topcoat Figure 11: Gloss values of red topcoat 7

11 Patcham additive package - Blue topcoat Table 7: Starting formulation coil coating blue topcoat Raw materials Weight (%) Mill base Saturated polyester Pat-Add DA PB 15: Solvesso Organo clay thickener 0.50 Letdown Saturated polyester Melamine formaldehyde Pat-Add LE Pat-Add AF Acid catalyst 0.50 Solvesso SOP dispersant Total % Figure 12: Saturated polyester : melamine formaldehyde coil coating system Resin ratio (PE:MM) 60:40 Peak metal temperature 2320 C Bar coater #36 DFT of primer 5µm 30 CIE lab measurements.6 Gloss Values L* and b* Values DA 947 Ref A Ref B ΔE Gloss Values DA 947 Ref A Initial Ref B Gloss values 20 o Gloss values 60 o L* b* Rub-out test,de Figure 13: Colour values of blue topcoat Figure 14: Gloss values of blue topcoat 8

12 Rubout tests on panels Rub out test of tinted topcoats Reference E = 0.55 Pat-Add DA 947 E = 0.40 Reference E = 0.74 Pat-Add DA 947 E = 0.29 Reference E = 1.33 Pat-Add DA 947 E = 0.70 Reference E = 1.92 Pat-Add DA 947 E =

13 Coil coating panels Coil coating primer Coil coating topcoat 10

14 Notes

15 Notes

16 PATCHAM (FZC) P.O. Box: 7753, Saif Zone, Sharjah, UAE Tel: Fax: PATCHAM INDIA B-52, Pravasi Industrial Estate Vishweshwar Nagar, Off Aarey Road Goregoan (E), Mumbai (India) Tel: india@patchamltd.com PATCHAM EUROPE BV Klavermaten DD Goor Netherlands eu@patchamltd.com PATCHAM USA LLC 10 Commerce Road Fairfield, New Jersey Tel: (201) Fax: (201) info@patchamusa.com The information given in this booklet is intended for technical guidance without obligation. Ver. 1.0