iting technology to plastic films. Work- ing with B.H.P. Steel Group and Aus- tralian Challenge (Victoria, Australia) A Packaging researchers found that the technology not only provided corrosion protection but made possible development of new packaging equipment. For nearly Concept for the 7 years, the company has continued to expand its packaging with vapor phase corrosion inhibitor (VpCI) film, achiev- ing dramatic reduction from prior cor- rosion claims with standard kraft/poly New Millennium steel wraps. At the same time, International BORIS A. MIKSIC, FNACE, AND ROBERT W. KRAMER Packaging Machines, Inc., of Naples, Florida, built the world’s largest stretch Vapor-phase corrosion inhibitor stretch film wrapper for Sumitomo Light Metals of packaging is ready to meet the packaging Nagoya, Japan, to wrap 23-t (20,866- challenges in the new millennium. While in kg) coils of aluminum, 8-ft (23-m) di- ameter, loaded eye vertical on 2.5-t the form of stretch film for bundling purposes has been (2,268-kg) steel platforms without steel used throughout industry for more than 25 years, the banding. Armed with this information, inclusion of environmentally friendly corrosion inhibitors the researchers began developing the through an innovative technology opened doors in the high-performance stretch film that steel industry. Cortec Corp. subsequently patented1-19 and targeted for tinplate and other metal packaging applications where superior corrosion protection and holding force are critical. uring the past 3 decades, The holding power of steel packaging re- through its elasticity curve was far mained basically un- greater than that of steel . The changed using various normal cross pattern of two steel bands combinations of kraft with break strength of 10,200 lb (4,627 , corrugated kraft, kg) used to secure primary tinplate coils reinforced kraft on skids is overshadowed by 120,000-lb with polyethylene (PE) laminates and (54,432-kg) break strength of 40 wraps Dcoating, kraft fiberboard, and metal fab- 2-mil (50-µm) film stretched 150% (Fig- ricated . Commingling mate- ure 1). The unique linear molecular rials do not meet demands for structure of plastic stretch film, particu- or even to achieve larly the use of advanced resin com- environmental objectives. The new pounds, makes possible superior load- millennium will entail greater focus on holding force in stretch wrap environmental concerns and require applications. that all materials produced be recycled. Multimetal VpCIs are compounded in the resins used to extrude the film. These VpCIs are chemical compounds Inhibited Stretch Wrap that vaporize from the film and con- Packaging dense onto the surface of the metal, This concept emerged in the early forming a thin, monomolecular, uni- 1990s when Cortec Laboratories began form, and effective corrosion-protect- researching the feasibility of introduc- ing layer. It protects even in recessed ing non-sodium nitrite corrosion-inhib- areas where the film is not in direct

24 CORTEC CORP. Supplement to Materials Performance, January 2001 FIGURE 1 contact. The patented Cor-Pak VCI improved holding force with fewer Stretch Film† manufactured with linear wraps. Alternating the wrap sequence low-density PE resins (LLDPE) is trans- to cover two corners, then cycling up parent, fully recyclable, and nontoxic, around the coil opposite the wrapped with pre-stretch capability up to 350%. corners, and repeating them for all four This U.S. Food and Drug Administra- sides, became a major improvement. tion (FDA)-approved technology The program basically consists of five makes the film ideal for tinplate and (a) Steel banded scroll load tinplate. wrap cycles for each side of the skid, food-processing applications. five wraps cycling up on the coil, eight wraps at the top and five down, and System for Tinplate Coils two final wraps around the skid perim- While the aluminum industry used eter to finish. These 40 wraps have stretch film for years as an , proven more than sufficient to hold 12- Weirton Steel Corp. (Weirton, West t coils on the skid in conjunction with Virginia), perfected the viable system a 1/2-in. (1.3-cm) felt pad of 5-lb (2.2- for tinplate coils. kg) density under the coil to dampen The concept to stretch wrap tin- vibration. Average film consumption plate coils was considered through all (b) Roped stretch wrap scrol tinplate. varies between 1.7 and 2.5 lb (.77 and levels at the company as a potentially 1.1 kg) depending on coil and skid size. The linear molecular structure of plastic stretch Since the company went into full significant cost-reduction alternative. A film allows for strong load-holding force. series of trials was conducted early in production with stretch wrap film 1994 using an IPM Model R0-88† rotary packaging in September 1995, it has overhead semiautomatic stretch wrap- shipped in excess of 300,000 coils both which went online January 1995 in per over a 6-month period with coils domestically and export without placement over an existing coil pack- averaging 54-in. (137-cm) diameter on failure. aging conveyor line. 56-in. (142-cm) skid platforms. It quickly became apparent why Coils of 12-t (10,886-kg) weight CONTROLLING DAMAGE pioneering poses greater risks than fol- wrapped with 2-mil film pre-stretched AND RUST lowing prior knowledge. While the 250% developed a strong force-to-load Figure 2 shows the prepared coil American Iron & Steel Institute (AISI)- strength with 38 to 48 wraps. It be- before and after stretch wrapping. The approved standard skid design is con- purpose of the package is to protect came evident in the trials that coil size, figured for steel strapping, no changes as related to skid size, posed a particu- the coil from damage and rust. De- were contemplated for stretch wrap- signed to be as airtight and waterproof lar problem. The larger the gap be- ping. Sharp corners became a critical as possible, each component is there tween coil and skid corner, the greater issue as film force-to-load strength was to maintain this condition through all the propensity for film puncture and so great that the stretch film began real-world conditions. The VpCI used failure at the corner. migrating up off the corners and punc- in the package is not the cure all if the Various methods to resolve this tured when the gap between coil and product and package are compro- problem ultimately resulted in a 2-in. skid corner increased because of coil mised. It is the important last line of (5-cm) corner radius specification on diameter variation. Without positive defense that must be understood for all skid corners. Trial shipments con- hold at all corners, holding strength proper application. As shown in Fig- firmed projected holding force as well was compromised greatly, causing ure 3, the steel company has achieved as handling and corrosion protection. coils to shift on the skids. Minor modi- significant reduction in rust claims Specific trials to evaluate dew point fications were made to resolve these since the introduction of its stretch conditions developed some condensa- issues. A 2-in. radius on skid corners wrap pack. The improvements in dam- tion situations, but the VpCI prevented minimized film puncture, and a 1-in. age control were adversely impacted corrosion. (2.5-cm) bevel at the top of skid run- in 1998 because of extraordinary con- Following extensive trials, the ners flush with lead platform boards ditions at one customer. Currently, the company’s management approved pur- allowed film to lock the coil to the skid. company is focusing on training ware- chase of a fully automatic rotary over- The wrapping sequence originally house and shipping personnel to head stretch-wrapping machine, programmed was further enhanced by achieve optimum results. It has worked the company’s Tin Mill engineers to closely with customers to institute new † Trade name. rope or neck down the film width for procedures. In severe situations, it has

Supplement to Materials Performance, January 2001 CORTEC CORP. 25 FIGURE 2

ark, New Jersey) now packages all loads by stretch-wrapping—even type C loads of uneven size slit mults for ex- port that would otherwise be impos- sible to securely band on skids. BMAT (formerly U.S. Can) (Chicago, Illinois) transitioned from kraft/poly steel wrap to VpCI poly to its current use of VpCI stretch film for all undecorated can stock. It is in the process of con- (a) (b) verting all litho decorated accordingly. A 12-t coil is shown before and after stretch wrapping. Trials currently underway at Crown Cork & Seal (Concord, Ontario, Canada) for wrapping cut-length deco- used third-party consultants to investi- distributed to all parties involved, rated tinplate have been designed to gate and resolve problems. Figure 4 il- including customers and insurance car- utilize the “roping” technique with lustrates progress made by the package riers. So far, the company reports the VpCI stretch film. This procedure en- design and joint effort with shippers, export pack has performed very well, tails programming the wrapping se- warehouse, and customers. reducing material and claims costs. quence similar to Weirton’s work with Considerable effort was given to Construction of the export is primary coils, whereby the film is trucking firms to help them better un- formed in two parts. The top cap has a necked down or narrowed to a rope derstand the handling of tin plate. 20-mil (508-µm) black appearance and placed over the top Manuals with specific instructions (PP) circle glued to a double-wall cor- were developed for use in training. rugated disc in between and sand- corners for increased vertical holding Random inspections were conducted wiched at the outer edge of a black force. to ensure directions were being fol- plastic corrugated edge protector. This lowed. The company firmly believes cap is placed down over a Super A FIGURE 3 that 100% use of web strapping of Flute† circumfer- loads on trucks and rail would elimi- ence or “belly wrap” that is also wax- nate most damage. In the meantime, coated to provide an extra moisture rubber-backed steel-edge protectors barrier. The export case is placed over provide the best defense against chain and in addition to the standard VpCI damage. Figure 5 shows what can be stretch pack. The load is then stretch- accomplished by working closely with wrapped a second time for shipment. a customer. The impact of the 1997 damage increase resulted in a new A company achieved significant reduction in turnover installation at the customer New Markets— rust claims after using stretch wrap packing for with good results and no rust in 1998. New Opportunities corrosion control. This customer fully expects further Proven success at steel industry reduction in damage. firms spawned new applications at Dofasco, Inc. (Hamilton, Ontario, FIGURE 4 NEW EXPORT STRETCH PACK Canada), Thomas Steel Strip (Warren, Deviating from “canned” metal case Ohio), Interstate Steel (Chicago, Illi- export pack specifications posed a real nois), National Rolling Mills (Philadel- challenge for the steel company. A phia, Pennsylvania), and Ovako Steel “plastic case” package was developed (Sweden), all of which have benefited for the company by R.I.G. Packaging from elimination of corrosion claims. (Pittsburgh, Pennsylvania), to integrate Wherever there is metals processing, into the existing stretch system. Accep- there is opportunity for stretch pack- tance problems and damage caused by aging. For example, TPC Metals (New- poor handling resulted from lack of un- Joint efforts with shippers, warehouse, and customers resulted in new procedures to derstanding of tin plate. A summary of successfully use stretch wrap packaging. a critical items list was developed and † Trade name.

26 CORTEC CORP. Supplement to Materials Performance, January 2001 FIGURE 5

The introduction of molded plastic Bibliography skid platforms should further enhance Australian Challenge, 103 Cheltenham, Victoria 3192 the concept of stretch film packaging. Australia 61 395 55 4944. Cortec Corp., 4119 White Bear Parkway, St. Paul, MN New designs accommodate the in- 55110. creased use of stretch wrap/roping. R.I.G. Packaging, 250 Rothesay Ave., Carnegie, PA 15106. Weirton Steel Corp., 400 Three Springs Dr., Weirton, West Virginia 26062-4989. Environmental Advantages A new turnover installer solved a rust problem Although improved cost effective- for one facility. A version of this article was published in the May 1999 issue of Steel Times maga- ness would alone justify this new pack- zine. Published with permission. aging concept for the new millennium, 12. “Vapor Phase Corrosion Inhibitor Packaging BORIS MIKSIC, FNACE is President of Cortec other advantages could become Utilizing Plastic Packaging ,” U.S. Patent No. Corp., 4119 White Bear Pkwy., St. Paul, MN 55110. equally or perhaps even more signifi- 5,517,945. He has developed more than 300 products and cant in the future. Recyclability of en- 13. “Anti-corrosion Containing Re- systems that use VpCIs and volatile corrosion cycled Resin,” U.S. Patent No. 5,855,975. inhibitors. He has an M.E. from the University of vironmentally friendly VpCI films will 14. B.A. Miksic, “Anti Corrosion Plastic Film Con- Zagreb, is a NACE Fellow, and has been a NACE become more important in the future, taining Recycled Resin,” European Patent No. 0653454. member for 26 years. particularly as manufacturers become 15. B.A. Miksic, et al., “Biodegradable Vapor Cor- ROBERT W. KRAMER is a packaging consultant at responsible for materials through their rosion Inhibitor Products,” U.S. Patent No. 6,028,160. Cortec Corp. He innovated the concept of stretch- 16. B.A. Miksic, et al., “Biodegradable Film,” Eu- useful life cycle and disposal. For the ropean Patent No. 00301117.8-2102. wrapping tinplate coils on skids using VpCI stretch steel industry, it becomes possible to 17. B.A. Miksic, et al., “Corrosion Inhibiting Ther- film. Throughout his 40-year career in paper and moplastic Alloys,” U.S. Patent No. 6,054,512. packaging he has been devoted to developing new extend a commitment to environmen- 18. B.A. Miksic, et al., “Biodegradable Film,” U.S. ideas as a technician, sales representative, and tal objectives and recycling to not only Patent No. 6,156,929. manager of manufacturing and distribution. He has a the product but also the package. With 19. “Vapor Phase Corrosion Inhibitor—Desiccant B.S. in business administration from Ohio State Material,” Japanese Patent No. 3,121,489. University. a simple slice of a razor-cutting knife, <2-lb (.91-kg) film is easily peeled from the load, rolled into a small ball, and tossed into the recycling bin.

Acknowledgment The authors thank the individuals, companies, and institutions mentioned in this article for their vision and com- mitment to achieve better corrosion prevention and control.

References 1. B.A. Miksic, “Vapor Phase Corrosion Inhibitor Desicant Material,” U.S. Patent No. 5,139,700. 2. B.A. Miksic, “Vapor Phase Corrosion Inhibitor Desiccant Material,” U.S. Patent No. 5,209,869. 3. “Vapor Phase Corrosion Inhibitor Desiccant Material,” U.S. Patent No. 5,320,778 4. “Method of Inhibiting Corrosion of Concrete Reinforcements,” U.S. Patent 5,326,529. 5. “Vapor Phase Corrosion Inhibitor Desiccant Material,” U.S. Patent No. 5,393,457. 6. “Vapor Phase Corrosion Inhibitor Desiccant Material,” U.S. Patent No. 5,332,525. 7. “Vapor Phase Corrosion Inhibitor Desiccant Material,” U.S. Patent No. 5,344,589. 8. “Anti-corrosion Plastic Film Containing Re- cycled Resin,” European Patent 94304176.4. 9. “Vapor Phase Corrosion Inhibitor Desiccant Material,” South African Patent No. 94/1033. 10. “Vapor Phase Corrosion Inhibitor—Desiccant Material,” U.S. Patent No. 5,422,187. 11. “Anti-corrosion Plastic Film Containing Re- cycled Resin,” Australian Patent No. 675317.

Supplement to Materials Performance, January 2001 CORTEC CORP. 27