Tetrashield MP2000 protective resin system for metal packaging coatings

Transcription

1 Tetrashield MP2000 protective resin system for metal packaging coatings

2 Eastman Tetrashield MP2000 protective resin system is a highly durable, BPA-free resin system that enhances the performance of metal packaging coatings. With high solids, improved retort resistance, and broad chemical resistance, formulations featuring Tetrashield MP2000 can achieve superior performance results in interior food-contact metal packaging applications. MP2000-based formulations can also be used for ends, caps and closures, and general line applications to improve coating performance as well as achieve high-solids coating formulations. Key attributes Improved sterilization resistance Enhanced corrosion protection Ability for higher applied formulation solids due to lower resin viscosity Flexibility and toughness to withstand fabrication Typical resin physical properties Solvent Aromatic 100:Aromatic 150ND (95:5) % Nonvolatiles 55 Viscosity, poise (Brookfield DV-II, spindle #5, 50 rpm, 25 C) 40 Color, APHA < 150 Acid number, mg KOH/g 3 Hydroxyl number, mg KOH/g 15 Glass transition temperature, C 76 Molecular mass a 6,200 a Based on carboxyl and hydroxyl end groups Cross-linker selection Tetrashield MP2000 is compatible with common hydroxyl-reactive curing resins. Suitable cross-linker choices include aminoplasts, phenolics, polyurethane hardeners, and combinations of one or more of the cross-linking chemistries. m-cresol resins (specifically, Curaphen ) work well in combination with MP2000. Benzoguanamine chemistries, such as Maprenal BF 892, Cymel 1123, and Maprenal BF 89, are effective cross-linkers when used in MP2000-based formulations. Thermally activated polyurethane cross-linkers, such as Desmodur BL 2078/2, are also recommended for use when formulating metal packaging coatings.

3 Catalyst selection Full film performance is achieved by incorporating a catalyst to maximize the extent of cross-linking. Catalyst selection and level will depend on cross-linker type and should be optimized for individual formulations. Examples of catalysts that are effective with Tetrashield MP2000-based formulations are urethane reaction catalysts, such as Fascat 9102; phosphoric acid catalysts, such as Cycat XK 406 N; and strong acid catalysts, such as dodecylbenzenesulfonic acid (DDBSA). Additives and formulation techniques Solvent selection Tetrashield MP2000 can be formulated with solvents commonly used as liquid carriers for coatings applications. Examples of suitable solvents for use in MP2000-based metal packaging formulations are glycol ethers, such as Eastman EB solvent; ketones, such as Eastman methyl n-amyl ketone (MAK); aromatic hydrocarbons, such as aromatic 100, aromatic 150, and xylene; and glycol ether esters, such as Eastman PM acetate. The amount and type of solvent used in the formulation should be driven by desired application viscosity, solvent evaporation profile needed for the curing operation, and rheological properties necessary for the application conditions. Pigmentation For white lacquer formulations with improved hiding powder, pigment like titanium dioxide (TiO 2 ) can be added to the formulation. Tetrashield MP2000-based formulations are compatible with most commercial TiO 2. Multiple TiO 2 types and grades exist depending on the pigment supplier. The specific pigment package is at the discretion of the formulator. Pigmentation levels of wt% of total formulation solids are recommended with MP2000-based formulations. A pigment-to-volume concentration (PVC) ladder study is suggested to optimize a balance of desired hiding versus flexibility and sterilization resistance. Slip additives Slip additives are used to reduce friction, increase gloss level, and prevent wear of the equipment. Incorporation of a lubricant, like a wax, can help to impart surface-slip properties during the fabrication stage. There are a variety of commercial waxes, such as carnauba-based materials and polyethylenetype lubricants, that are used in metal packaging applications. Compatibility of lubricant additives with Tetrashield MP2000-based formulations will vary depending on solvent package and cross-linker selection and should be tested prior to incorporation. Other additives Other specialty additives can also provide the formulation with enhanced application properties to achieve maximum coating performance. Flow agents can be used to improve flow and leveling during application and curing. Deaerating agents help eliminate air at the interface. Adhesion promotors can also be added to the formulation to enhance adhesion to the applied substrate.

4 Application recommendations Coatings formulations based on Tetrashield MP2000 are effective over a variety of metal substrates, including steel, tin-free steel, tin plate, and aluminum. MP2000-based formulations can be applied to the substrate either prior to or after article formation because of its excellent fabrication properties. Standard curing conditions for evaluating the recommended starting point formulas are recommended at a peak metal temperature of 200 C for 10 minutes. Dry film thickness (DFT) targets are mil ( µ) for most food packaging applications but should be adjusted based on final endperformance needs. When replacing existing BPA-NI materials in a formulation with Tetrashield MP2000, it may be necessary to adjust the solvent package to obtain the same rheological profile, as it does provide a reduced viscosity profile over commercial BPA-NI materials. White polyurethane (PU) formulation Raw material Weight (%) lb/100 gal gal/100 gal Supplier Grind Tetrashield MP Eastman Aromatic Ti-Pure R900 TiO Chemours Subtotal Letdown Desmodur BL 2078/ Covestro Fascat PMC Organometallix Aromatic Total MP2000 white polyurethane formulation physicals MP2000 white polyurethane typical performance properties a % Nonvolatiles, weight 59.6 Property Test Typical value % Nonvolatiles, volume 40.1 Application viscosity CAP, 30 C, poise 2.9 Pigment-to-binder weight ratio 1.08:1 Dry film thickness mils 0.62 NCO:OH eq. ratio 1.47:1 Wedge bend mm failure 52 VOC, g/l 521 LAS retort ( 20 gloss) Gloss measurement before/after exposure VOC, lb/gal 4.35 Solvent resistance Acetone double rubs, # 70+ Pounds per gallon 10.8 a Films applied with a wire-wound rod to ETP at a target DFT of 0.6 mils; cure conditions: flash dried for 15 minutes at ambient conditions then cured for 12 minutes at 200 C. 0.8

5 White polyurethane formulation benchmarking performance Tetrashield MP2000-based white polyurethane lacquer was compared to a commercial high-molecularweight, high-t g (~100 C) BPA-NI polyester resin in the same starting point formulation. To understand wet adhesion strength after deformation at the coating/substrate interface, a cathodic disbonding test was performed. This test is administered by passing current through the coated metal (cathode) to the anode at a known voltage for a specified length of time. Following exposure to the current, a tape test is administered to remove the coating from the substrate where delamination has occurred. The MP2000-based formulation demonstrates superior mechanical performance and adhesion over the control even when exposed to a harsh corrosive condition. It gives a lower application viscosity at isosolids compared to the commercial BPA-NI resin. White PU formulation Control MP2000 Formulation viscosity, P Wedge bend, % failure Acetone double rubs, # LAS retort (delta gloss) Control MP2000 Cathodic disbonding of white PU coatings: adhesion results after exposure to 2 volts for 5 minutes followed by tape test

6 White benzoguanamine-polyurethane hybrid (BPUH) formulation Raw material Weight (%) lb/100 gal gal/100 gal Supplier Grind Tetrashield MP Eastman Aromatic Ti-Pure R900 TiO Chemours Subtotal Letdown Maprenal BF Ineos Desmodur BL 2078/ Covestro Fascat PMC Organometallix Aromatic Total MP2000 white benzoguanaminepolyurethane formulation physicals MP2000 white benzoguanamine-polyurethane typical performance properties a % Nonvolatiles, weight 56.0 Property Test Typical value % Nonvolatiles, volume 38.0 Application viscosity CAP, 30 C, poise 2.2 Pigment-to-binder weight ratio 0.85:1 Dry film thickness mils 0.6 NCO:OH eq ratio 0.73:1 Wedge bend mm failure 22 VOC, g/l 540 LAS retort ( 20 gloss) Gloss measurement before/after exposure VOC, lb/gal 4.5 Solvent resistance Acetone double rubs, # 70+ Pounds per gallon 10.2 a Films applied with a wire-wound rod to ETP at a target DFT of 0.6 mils; cure conditions: flash dried for 15 minutes at ambient conditions then cured for 12 minutes at 200 C. 14 White benzoguanamine-polyurethane hybrid formulation benchmarking performance The Tetrashield MP2000-based white BPUH coating formulation was compared to a commercial mid-molecular-weight, high-t g (~60 C) BPA-NI polyester resin in the same starting point formulation. The MP2000-based formulation gave improved flexibility and sterilization resistance compared to the commercial resin. White BPUH formulation Control MP2000 Formulation viscosity, P Wedge bend, % failure Acetone double rubs, # LAS retort (delta gloss) White hybrid formulations with Tetrashield MP2000 can be tailored to improve fabrication properties of the article.

7 Gold phenolic-polyurethane hybrid formulation Raw material Weight (%) lb/100 gal gal/100 gal Supplier Tetrashield MP Eastman Curaphen Bitrez Desmodur BL 2078/ Covestro Fascat PMC Organometallix Aromatic Total MP2000 gold phenolic-polyurethane formulation physicals MP2000 gold phenolic-polyurethane typical performance properties a % Nonvolatiles, weight 40.2 Property Test Typical value % Nonvolatiles, volume 32.2 Application viscosity CAP, 30 C, poise 1.3 NCO:OH eq ratio 0.85:1 Dry film thickness mils 0.6 VOC, g/l 588 Wedge bend mm failure 0 VOC, lb/gal 4.9 LAS retort ( 20 gloss) Gloss measurement before/after exposure Pounds per gallon 8.2 Solvent resistance Acetone double rubs, # 50+ a Films applied with a wire-wound rod to ETP at a target DFT of 0.6 mils; cure conditions: flash dried for 15 minutes at ambient conditions then cured for 12 minutes at 200 C. 16 Gold phenolic-polyurethane benchmarking performance The Tetrashield MP2000-based gold phenolic-polyurethane hybrid coating formulation was compared to a commercial high-molecular-weight, high-t g (~100 C) BPA-NI polyester resin in the same starting point formulation. The MP2000-based formulation gave improved flexibility and reduced viscosity compared to the commercial resin. The MP2000-based coating gave comparable fabrication properties to the control. Gold phenolic-polyurethane formulation Control MP2000 Formulation viscosity, P Wedge bend, % failure 5 0 Acetone double rubs, # LAS retort (delta gloss) Formulating with Eastman Tetrashield MP2000 improves the balance of performance, cost, and longterm durability of BPA-NI metal packaging coatings while optimizing the coating process. Tetrashield MP2000 has been shown in laboratory tests to offer a unique combination of flexibility, corrosion resistance, and manufacturing throughput, enabling superior protection of food, beverages, and consumer products in a BPA-free formulation. A good can preserves more than food. It preserves trust. Tetrashield protects the food and beverage cans that consumers trust and brands are proud to put their names on. For more information, visit Eastman.com/Tetrashield.

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