The fractions of nano-sized particles significantly increase the effectiveness of protective paints, coatings, primers and waxes for metal.
The use of graphene nanosheets to significantly improve performance is a relatively new but rapidly growing application area in the paint industry.
While their use in metal protection products is fairly new—only commercialized in the last few years—graphene nanosheets (NNPs) have been proven to have a huge impact on the properties of primers, coatings, paints, waxes, and even lubricants. Although the typical pressure control ratio varies from a few tenths to a few percent, the correct addition of GNP will become a multifunctional additive that can greatly extend the service life and durability of the coating, improve chemical resistance, corrosion resistance, oxidation resistance and abrasion resistance. ; even helps the surface to easily remove water and dirt. In addition, GNPs often act as synergists, helping other supplements work more effectively at lower concentrations without sacrificing effectiveness. Graphene nanosheets are already commercially used in metal protection products ranging from automotive sealants, sprays and waxes to primers and paints used by automakers, building contractors and even consumers. More applications (such as marine antifouling/anticorrosive primers and paints) are reported to be in the final stages of testing and are expected to be commercialized over the next few years.
Researchers at the University of Manchester (Manchester, UK) were the first to isolate single-layer graphene in 2004, for which they were awarded the 2010 Nobel Prize in Physics. Graphene nanosheets — a multi-layered form of graphene available from various vendors with varying particle thicknesses and medium sizes — are flat/scaly nanosized 2D forms of carbon. Like other nanoparticles, the ability of GNPs to change and improve the properties of macroscopic products such as polymer films, plastic/composite parts, coatings, and even concrete is completely out of proportion to their tiny size. For example, the flat, wide yet thin geometry of GNP additives makes them ideal for providing effective surface coverage without increasing coating thickness. Conversely, their effectiveness in improving coating performance often means that less coating is required or thinner coatings can be applied. The GNP material also has a very high surface area (2600 m2/g). When properly dispersed, they can significantly improve the barrier properties of coatings to chemicals or gases, resulting in improved protection against corrosion and oxidation. In addition, from a tribological point of view, they have very low surface shear, which contributes to improved wear resistance and slip coefficient, which helps to give the coating better scratch resistance and repels dirt, water, microorganisms, algae, etc. Considering these properties, it is easy to understand why even small amounts of GNP additives can be so effective in improving the properties of the vast array of products the industry uses every day.
Although they, like other nanoparticles, have great potential, isolating and dispersing graphene nanosheets in a form that can be used by paint developers or even plastics formulators is not easy. Delaminating larger aggregates of nanoparticles for efficient dispersion (and dispersion in shelf-stable products) for use in plastics, films, and coatings has proven challenging.
Commercial GNP companies typically offer various morphologies (single-layer, multi-layer, various average diameters and, in some cases, with added chemical functionality) and various form factors (dry powder and liquid [solvent-based, water-based or resin-based] dispersions for various polymer systems). Manufacturers most advanced in commercialization said they worked closely with paint formulators to find the best combination of properties at the most efficient dilution ratios to improve paint quality without negatively impacting other key properties. Below are some companies that can discuss their work in the field of protective coatings for metals.
Car care products were one of the first and most significant applications of graphene in the paint industry.Photo: Surf Protection Solutions LLC
One of the first commercial applications of graphene metal protection products was in automotive trim. Whether used in liquid, aerosol, or wax formulations, these high performance car care products can be applied directly to car paint or chrome, improving gloss and depth of image (DOI), making cars easier to clean, and maintaining cleansing and broadening properties. protection is far superior to conventional products. GNP-enhanced products, some of which are sold directly to consumers and others sold only to beauty salons, compete with ceramic (oxide) enriched products (containing silica, titanium dioxide, or a mixture of both). Products containing GNP have higher performance and higher price as they offer several important benefits that ceramic coatings cannot provide. Graphene’s high thermal conductivity effectively dissipates heat — a boon for products used in hoods and wheels — and its high electrical conductivity dissipates static charges, making it harder for dust to stick. With a large contact angle (125 degrees), GNP coatings flow faster and more efficiently, reducing water spots. Excellent abrasive and barrier properties better protect the paint from scratches, UV rays, chemicals, oxidation and warping. The high transparency allows GNP-based products to retain the glossy, reflective appearance that is very popular in this sector.
Surface Protective Solutions LLC (SPS) of Grafton, Wisconsin, a formulation maker with a strong foothold in this market segment, sells a durable solvent-based graphene coating that lasts for years and sells a graphene-enhanced water-based paint. Serum for a quick touch-up that lasts for several months. Both products are currently only available to trained and licensed estheticians, although there are plans to offer cosmetics and other aftercare products directly to consumers in the near future. Target applications include cars, trucks, and motorcycles, with other products said to be close to being commercialized for homes and boats. (SPS also offers an antimony/tin oxide product that provides UV protection to the surface.)
“Traditional carnauba waxes and sealants can protect painted surfaces from weeks to months,” explains SPS President Brett Welsien. “Ceramic coatings, introduced to the market in the mid-2000s, form a stronger bond to the substrate and provide years of UV and chemical resistance, self-cleaning surfaces, higher heat resistance and improved gloss retention. However, their weakness is water stains. surface paint and surface smudges that our own tests have shown to be caused by poor heat transfer Fast forward to 2015 when research on graphene as an additive began In 2018 we were the first company in the US to officially launch a graphene paint additive in the process of developing the company’s products based on GNP, researchers found that water stains and surface stains (due to contact with bird droppings, tree sap, insects and harsh chemicals) were reduced by an average of 50%, as well as as improved abrasion resistance due to the lower coefficient of friction.
Applied Graphene Materials plc (AGM, Redcar, UK) is a company that supplies GNP dispersions to a number of customers developing car care products. The 11-year-old graphene manufacturer describes itself as a world leader in the development and application of GNP dispersions in coatings, composites and functional materials. In fact, AGM reports that the paints and coatings industry currently accounts for 80% of its business, likely because many members of its technical team come from the paints and coatings industry, which helps AGM understand the pain points of the two compilers and ultimately , users. .
Halo Autocare Ltd. (Stockport, UK) uses AGM’s Genable GNP dispersion in two EZ car care wax products. Released in 2020, graphene wax for body panels combines T1 carnauba wax, beeswax, and fruit nut oil with polymers, wetting agents, and GNP to change surface water behavior and provide long-term protection, excellent water beads and films, low dirt collection, easy to clean, eliminates bird droppings and greatly reduces water stains. Graphene Alloy Wheel Wax has all of these benefits, but is specifically designed for higher temperatures, increased wear on wheels and exhaust tips. GNP is added to the base of high temperature microcrystalline waxes, synthetic oils, polymers and curable resin systems. Halo says that depending on use, the product will protect wheels for 4-6 months.
James Briggs Ltd. (Salmon Fields, UK), which describes itself as one of Europe’s largest household chemical companies, is another AGM customer using GNP dispersions to develop its Hycote graphene anti-corrosion primer. Zinc-free fast drying aerosol spray has excellent adhesion to metals and plastics and is used by people such as body shops and consumers to stop or prevent corrosion of metal surfaces and to prepare those surfaces for painting and coating. The primer provides more than 1750 hours of corrosion protection in accordance with ASTM G-85, Appendix 5, as well as excellent barrier properties and flexibility without cracking in the cone test (ASTM D-522). primer life. AGM said it worked closely with customers during the formulation development process to maximize value-added properties while limiting the impact on product cost.
The number and types of GNP-enhancing car care products on the market are growing rapidly. In fact, the presence of graphene is touted as a major performance benefit and is highlighted on the product chart. | James Briggs Ltd. (left), Halo Autocare Ltd. (top right) and Surface Protective Solutions LLCSurface Protective Solutions LLC (bottom right)
Anti-corrosion coatings are a growing area of application for GNP, where nanoparticles can significantly extend maintenance intervals, reduce corrosion damage, extend warranty protection, and reduce asset management costs. | Hershey Coatings Co., Ltd.
GNPs are increasingly being used in anti-corrosion coatings and primers in difficult (C3-C5) environments. Adrian Potts, CEO of AGM, explained: “When properly incorporated into solvent- or water-based coatings, graphene can impart excellent anti-corrosion properties and improve corrosion control.” impact by extending the life of assets, reducing the frequency and cost of asset maintenance, and for water-based products or products containing more toxic additives such as zinc are no longer required or used. area of focus and opportunity over the next five years. “Corrosion is a big deal, rust is not a very pleasant topic because it represents the deterioration of the client’s assets, it is a serious problem,” he added.
An AGM customer that has successfully launched an aerosol spray primer is Halfords Ltd. based in Washington, UK, a leading British and Irish retailer of auto parts, tools, camping equipment and bicycles. The company’s graphene anti-corrosion primer is zinc-free, making it more environmentally friendly. It is said to have excellent adhesion to metal surfaces including mild steel, aluminum and Zintec, fill in small surface imperfections and dry in 3-4 minutes to a sandable matte finish in just 20 minutes. It also passed 1,750 hours of salt spray and cone testing without cracking. According to Halfords, the primer has excellent sag resistance, allows for greater depth of coating, and provides excellent barrier properties to significantly extend the life of the coating. In addition, the primer has excellent compatibility with the latest generation of water-based paints.
Alltimes Coatings Ltd. from Stroud, UK, a specialist in corrosion protection of metal roofs, uses AGM dispersions in its Advantage Graphene liquid roofing systems for industrial and commercial buildings. The product increases the minimum weight of the roof, is weather and UV resistant, free of solvents, volatile organic compounds (VOCs) and isocyanates. Only one layer is applied to a properly prepared surface, the system has impact resistance and high elasticity, excellent extensibility and no shrinkage after curing. It can be applied over a temperature range of 3-60°C/37-140°F and reapplied. The addition of graphene significantly improves corrosion resistance, and the product has passed the 10,000-hour neutral salt spray test (ISO9227:2017), extending Autotech’s warranty life from 20 to 30 years. Despite creating a highly effective barrier against water, oxygen and salt, the microporous coating is breathable. To facilitate the architectural discipline, Alltimes has developed a systematic Continuing Professional Development (CPD) curriculum.
Blocksil Ltd. from Lichfield, UK, describes itself as an award-winning coatings company providing advanced energy and labor saving solutions to customers in the automotive, rail, construction, energy, marine and aerospace industries. Blocksil worked closely with AGM to develop a new generation of MT anti-corrosion coatings with a graphene-reinforced top layer for structural steel in open and corrosive environments. Available in a variety of colors, the VOC and solvent free, single coat system is extremely moisture resistant and has surpassed 11,800 hours of neutral salt spray testing for 50% more durability than previous products. In comparison, Blocksil says that unplasticized polyvinyl chloride (UPVC) typically lasts 500 hours in this test, while epoxy paint lasts 250-300 hours. The company also says the paint can be applied to slightly damp steel and prevents water infiltration shortly after application. Described as being surface resistant, it will rust as long as loose debris is removed and cures without external heat so it can be used in the field. The coating has a wide application range from 0 to 60°C/32-140°F and has passed stringent fire tests (BS476-3:2004, CEN/TS1187:2012-Test 4 (including EN13501-5:2016-test 4). 4)) are graffiti resistant and have excellent UV and weather resistance. The coating was reported to have been used on launcher masts at RTÉ (Raidió Teilifís Éireann, Dublin, Ireland) and on communications satellites at Avanti Communications Group plc (London) and on segmented and parallel column (SSP) railway tracks, where it passed EN45545 -2:2013, R7 to HL3.
Another company using GNP-reinforced coatings to protect metal is global automotive supplier Martinrea International Inc. (Toronto), which uses graphene-reinforced polyamide (PA, also called nylon) coated passenger cars. (Because of its good thermoplastic properties, Montreal supplier GNP NanoXplore Inc. supplied Martinrea with an all-composite GNP/PA coating.) The product is reported to reduce weight by 25 percent and provide superior wear protection, enhanced superior strength, and improved chemical protection. resistance does not require any changes to existing production equipment or processes. Martinrea noted that the improved performance of the coating could extend its application to a wider range of automotive components, especially electric vehicles.
With the completion of numerous long-term tests, marine corrosion protection and anti-fouling are likely to become an important application of GNP. Graphene additive Talga Group Ltd. is currently being tested in real ocean conditions on two large ships. One of the vessels had just completed a 15-month inspection and it was said that sections coated with GNP reinforced primer showed comparable or better results than the original samples without reinforcement, which already showed signs of corrosion. | Targa Group Co., Ltd.
Many paint developers and graphene manufacturers have been hard at work developing anti-corrosion/anti-fouling coatings for the marine industry. Given the extensive and long-term testing required to gain approval in this area, most of the companies we interviewed indicated that their products are still in the testing and evaluation phase and non-disclosure agreements (NDAs) prevent them from discussing their work in the field. each stated that tests conducted to date have shown significant benefits from incorporating GNP into marine pavements.
One company that was unable to elaborate on its work is Singapore-based 2D Materials Pte. Ltd., which began producing GNP on a lab scale in 2017 and a commercial scale last year. Its graphene products are specifically designed for the paint industry, and the company said it has been working with two of the largest marine anti-corrosion coating suppliers since 2019 to develop paints and coatings for the sector. 2D Materials also said it is working with a major steel company to incorporate graphene into oils used to protect steel during shipping and storage. According to Chwang Chie Fu, an expert in the application of 2D materials, “graphene has the biggest impact on functional coatings.” “For example, for anti-corrosion coatings in the marine industry, zinc is one of the main ingredients. Graphene can be used to reduce or replace zinc in these coatings. Adding less than 2% graphene can significantly increase the life of these coatings, which means that this makes it a very attractive value proposition that is hard to refuse.”
Talga Group Ltd. (Perth, Australia), a battery anode and graphene company founded in 2010, announced earlier this year that its Talcoat graphene additive for primers has shown positive results in real world ocean tests. The additive is specifically formulated for use in marine coatings to improve corrosion resistance, reduce paint loss in aquatic ecosystems and improve performance by increasing dry dock interval. Notably, this dry-dispersible additive can be incorporated into coatings in situ, which represents a significant commercial development of GNP products, which are usually supplied as liquid dispersions to ensure good mixing.
In 2019, the additive was premixed with a two-pack epoxy primer from a leading coating supplier and applied to the hull of a large 700m²/7535ft² container ship as part of a sea trial to evaluate the performance of the coating in harsh marine environments. (To provide a realistic baseline, a traditional labeled primer was used elsewhere to distinguish each product. Both primers were then topcoated.) At the time, this application was considered the world’s largest graphene application. The vessel underwent a 15-month inspection and the sections coated with GNP reinforced primer reportedly performed comparable or better than the baseline without reinforcement, which already showed signs of corrosion. The second test involved having the paint applicator mix the powdered GNP additive on site with another two-pack epoxy paint from another leading paint supplier and spray it onto a significant portion of a large container. Two lawsuits are still ongoing. Talga noted that pandemic-related travel restrictions continued to affect international travel, delaying news on how the coverage is working on the second ship. Encouraged by these results, Talga is said to be developing anti-fouling marine coatings, anti-microbial coatings for metal and plastic, anti-corrosion coatings for bulky metal parts, and barrier coatings for plastic packaging.
GNP development project announced in March by Advanced Materials Research Laboratory Toray Industries, Inc. (Tokyo), attracted the interest of coating formulation developers, including the creation of an ultrafine dispersion graphene solution, which is said to exhibit excellent fluidity. High conductivity combined with high electrical and thermal conductivity. Key to the development is the use of a unique (unnamed) polymer that is said to control viscosity by inhibiting the aggregation of graphene nanosheets, thereby solving the longstanding problem of creating highly concentrated GNP dispersions.
Compared to conventional GNP dispersions, Toray’s new high-fluidity product, which contains a unique polymer that controls viscosity by preventing graphene nanoparticle aggregation, produces highly concentrated, ultra-fine GNP dispersions with high thermal and electrical conductivity and increased fluidity for ease of handling and mixing. | Torey Industries Co., Ltd.
“Thinner graphene tends to aggregate more easily, which reduces fluidity and makes it harder to apply dispersion blended products,” explains Toray researcher Eiichiro Tamaki. “To avoid the sticking problem, the nanoplates are usually diluted in a low concentration solution. However, this makes it difficult to achieve sufficient concentration to take full advantage of graphene.” ultra-fine GNP dispersion and increased fluidity for ease of handling and blending. Initial applications are said to include batteries, electronic circuits for printing, and anti-corrosion coatings to prevent water and oxygen from penetrating. The company has been researching and manufacturing graphene for 10 years and claims to have developed dispersion technology to make graphene more affordable. The researchers believe the unique polymer affects both the nanosheets themselves and the dispersion medium, Tamaki noted, saying it works particularly well with highly polar solvents.
Given all the potential benefits that GNP offers, it’s no surprise that over 2,300 GNP-related patents have been issued to businesses and academia. Experts predict significant growth for this technology, saying it will affect more than 45 industries, including paints and coatings. Several important factors hindering growth are eliminated. First, environmental, health and safety (EHS) concerns may be a problem for new nanoparticles as regulatory approval (eg the European Union’s REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) system) is eased. In addition, a number of suppliers have extensively tested GNP reinforcing materials to better understand what happens when sprayed. Graphene makers are quick to point out that because GNP is made from the naturally occurring mineral graphite, their process is inherently more environmentally friendly than many other additives. The second challenge is getting enough at an affordable price, but this is also being addressed as manufacturers expand their production systems.
“The main obstacle to the introduction of graphene into the industry has been the production capacity of graphene manufacturers, combined with the historically high cost of the product,” explains Tarek Jalloul of Lead Carbon Technologies, a NanoXplore technology project. “These two hurdles are being overcome and graphene-enhanced products are entering the commercial phase as the power and price gap is narrowing. For example, my own company was founded in 2011 and can now produce 4,000 t/t per year, according to IDTechEx Research (Boston ), we are the largest graphene manufacturer in the world. Our new manufacturing facility is fully automated and has a modular structure that can be easily replicated if expansion is needed. Another major barrier to graphene industrial applications is the lack of regulatory approval, but this is happening now.”
“The properties offered by graphene could have a major impact on the paints and coatings industry,” Velzin adds. “While graphene has a higher cost per gram than other additives, it is used in such small amounts and provides such positive benefits that the long-term cost is affordable. develop graphene ?coatings??
“This stuff works and we can show it’s really good,” Potts added. “Adding graphene to a recipe, even in very small amounts, can provide transformational properties.”
Peggy Malnati is a regular contributor to PF’s sister publications CompositesWorld and MoldMaking Technology magazines and maintains contact with clients through her regional office in Detroit. pmalnati@garpub.com
Masking is used in most metal finishing operations where only certain areas of the surface of the part need to be processed. Instead, masking can be used on surfaces where treatment is not required or should be avoided. This article covers many aspects of metal finish masking, including applications, techniques, and the different types of masking used.
Improved adhesion, increased corrosion and blister resistance, and reduced coating interaction with parts require pre-treatment.
Post time: Nov-28-2022