My three-year-old niece has a fascination with recycling and recycling trucks. Not garbage trucks, because those are stinky; no, she loves the green recycling trucks that come down the street once a week. According to my other friends with young children, this is common, which leads me to believe that Generation Alpha cannot get enough of trips to waste sorting facilities, recycling trucks and can collection machines.
I’m not sure where this interest comes from, but I think we can all agree that educating our youth about the importance of recycling is important. However, what should we teach them? There are still many questionsi about what products and materials we should recycle and how. Should consumers bag their recyclables? Can grocery bags and plastic wrappers be recycled? How are materials sorted after a consumer puts them in their curbside program? Furthermore, as my niece regularly asks, when do the magical green trucks come?
Plastics have become the “poster child” for confusing recycling rules. Many people think a plastic is recyclable when they see the chasing arrows symbol (accompanied by a number) on the packaging, but that number is actually used to identify the type of resin plastic, which makes it easier to sort out materials to be recycled. Therein lies the problem.
In an attempt to provide clarification, California passed SB-343, Environmental Advertising: Recycling Symbol: Recyclability: Products & Packaging.ii Other efforts to address confusion related to recycling are underway, but accordingiii to the United Nations Environment Programme (UNEP), only an estimated 9% of all plastics have been recycled. That means there’s still work to be done. The UNEP has established an Intergovernmental Negotiation Committee (INC) that is responsible for developing a plastics treaty. However, to do this effectively, it’s essential to understand the technology involved in recycling plastic products, packaging and material.
There are two main processes for recycling plastics that work in tandem—mechanical recycling and advanced (or chemical) recycling. Mechanical recycling breaks up plastic material, either by crushing, grinding or some other physical means to break down the material, which is then remelted into granules that can be used to create new products. Mechanical recycling is more common than advanced recycling because it’s what our current infrastructure is set up to handle. It is important to note that, for mechanical recycling, materials must first be sorted because it requires an uncontaminated waste stream and can only handle certain types of plastic. Mechanical recycling cannot be used on multilayer plastics because the process weakens the strength of the plastic, limiting the number of applications the recycled resin can create.
Advanced recycling is a newer technology for recycling plastics and is actually multiple technologies, such as enzymatic hydrolysis, methanolysis and glycolysis. These processes are used to break down plastic waste, which can then be used as a feedstock to manufacture new products by breaking down the polymer chains into monomers that can be used again to build new polymers. This process can remove contamination and produce chemicals with the same quality and physical properties as virgin material. Advanced recycling is more energy intensive than mechanical recycling and should be used as a complementary technology and not as a substitute, but it’s betteriv than virgin plastic production and can divert plastic that is unsuitable for mechanical recycling from incineration, landfills or the environment. Advanced recycling is currently limited in scale, but several companies in the European Union and the U.S. have made significant investments in this technology to develop and scale it for the future.
Our society has a diverse range of plastic materials and packaging, and it isn’t practical to think one single solution can manage all of that material. Public policy should encourage the development and advancement of new technologies to help recycling streams become more efficient and effective. Through these technological advances, we can produce more recycled resin to meet the needs of consumers and workers who depend on plastic.
Education on how to properly recycle is just as important as achieving these technological advances. Recycling correctly and minimizing contamination are essential to ensuring that plastic and other materials can be recycled into new products. The goal is to build a solid foundation for recycling so that future generations, whether that’s my niece’s generation or the generations that will come after, can focus on other issues rather than continue to address the shortfalls of turning our garbage into the products of the future.
For further information, please contact me at ngeorges@thehcpa.org. SPRAY
i link
ii link
iii link
iv City College of New York. “Advanced plastics recycling yields climate benefits.” ScienceDaily. ScienceDaily, 12 October 2022.
Michigan
On April 18, the Air Quality Division of the Michigan Dept. of Environment, Great Lakes & Energy finally promulgated its Final Rule for both Consumer Products and Architectural Coatings. Having gone through the legislative process, this ruling is now complete.
Please remember that Michigan had placed a Jan. 1, 2023, compliance date on both regulations. Until the rule was final, the State could not enforce this Jan. 1 rule date. Michigan staff has stated during a public webinar that it does not intend to enforce the rule. To be cautious, all products produced after April 18, 2023, should be compliant with the new Ozone Transport Commission (OTC) Model Rules. Product produced after April 18 should be made compliant with the OTC Consumer Products Model Rule IV and OTC Architectural Model Rule II.
Even with Michigan’s staff statement of no enforcement, companies should strive to come into compliance as soon as they can, even though there is an unlimited sell-through. If a product is picked up a year or 18 months from now, and was produced after April 18, 2023, the Michigan Air Quality Division could enforce on that product. If that happened, a company would then need to fight that enforcement action. Chances are good that the company would win, but company resources would have to be spent on that fight. In another scenario, Michigan Air Quality Division staff could turn over a year from now and new staff may have no knowledge of these statements of no enforcement. It is better to be safe than sorry.
OTC
On April 21, 2023, the OTC held a virtual stakeholders meeting. Francis Seitz from the New Jersey Dept. of Environmental Protection (DEP), who leads the OTC Stationery & Area Sources Committee, presented Committee updates. The good news is that there is no movement by OTC to develop any new Model Rules for Consumer Products or Architectural Coatings.
Seitz did mention that New Jersey will be updating its Consumer Products Rule to OTC Model Rule IV, likely this year. Therefore, we need to monitor this process to ensure consistency with the OTC Model Rule. While we dislike changes in Rules, it would be nice if all States (except California) would settle on one OTC Model Rule; this would make compliance (and life) much easier.
Other OTC States
Ohio’s OTC Rule change comes into effect on July 1, 2023, so all product produced after July 1 for sale in Ohio needs to be in compliance with OTC Model Rule IV. All products produced before this date, and properly date coded, have an unlimited sell-through. Only one month to go!
Colorado has set up a contingency Consumer Products Rule using a variation of OTC Model V that only becomes effective if the State fails to comply with the Air Quality standards. We will not know if this contingency measure is needed for at least two years.
Virginia is proposing to add a contingency Consumer Products Rule using OTC Model Rule IV. To reiterate, this is only being proposed.
New Jersey, as previously explained, will likely move from OTC Model Rule II to OTC Model Rule IV this year. The timing is currently unknown.
In Nevada, only Clark County (Las Vegas) is considering moving to OTC Model Rule IV. Clark County’s first draft left a lot to be desired, as it proposed a 30-day sell-through. Luckily, they are in the process of re-writing that proposal; we will need to wait and see the outcome.
Canada
Just a reminder that the Canadian Consumer Products Rule becomes effective on Jan. 1, 2024—therefore, only seven months to go. SPRAY
An aerosol product is used to deliver a wide variety of products, which means they are subject to a number of government laws and regulations. The aerosol industry constantly strives to create new products that improve the daily lives of consumers and workers while still complying with existing laws and regulations. Unfortunately, regulations can sometimes stifle the industry’s ability to innovate and bring new products to market. People typically associate regulations with government agencies such as the California Air Resources Board (CARB), the U.S. Food & Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA); however, the U.S. Dept. of Transportation (DOT) Pipeline & Hazardous Safety Administration (PHMSA) has also promulgated certain requirements for aerosol products.
PHMSA is responsible for developing and enforcing the regulations that ensure the safe transport of hazardous materials and products. Aerosol productsi are always subject to PHMSA’s requirements due to their pressurized natureii and can be assigned subsidiary hazards depending on the formulation. For this reason, an aerosol containeriii needs to meet rigorous material, design, construction, manufacturing and pressure testing requirements, and the shipping of aerosol products has additional requirements.
There are certain situations in which a company’s manufacturing process or product does not align with PHMSA’s regulations, including shipping a gas-only aerosol product, shipping an aerosol product in a container that doesn’t meet the wall thickness requirement, or utilizing an alternative technology to replace the water bath test. In these (and other) circumstances, a company can obtain a special permit from PHMSA that allows companies to still ship hazardous materials.iv
To receive a special permit, an application must be submitted at least 120 days before the requested effective date, provide a detailed descriptionv of the proposal and justify that the proposal is at least as protective as the regulations or show an analysis that shipping is safe if a certain scenario is not addressed by existing regulations.
While the timeline of PHMSA’s review of a special permit application will vary, it will ultimately either issue or deny the proposal a special permit. If it’s denied, the applicant can petition for reconsideration within 20 days of receipt of the decision and provide additional information needed to support the request.
When a special permit is granted, a company using the special permit must meet specific requirements documented within, such as special markings, providing additional documentation and training. When first issued, a special permit will not be effective for more than two years. Applicationsvi for renewing a special permit must be submitted at least 60 days prior to expiration and may be renewed for successive periods, but not more than four years. If a renewal does not occur, a company must reapply for a new special permit.
Federal hazardous materials transportation law requiresvii PHMSA to publish a notice in the Federal Register that an application for a new special permit or a modification to an existing special permit has been filed (though no confidential information is released) and gives the public an opportunity to inspect the safety analysis and provide comment. PHMSA also maintains an online toolviii that allows the public to search for special permits by number, company name or State.
While transporting aerosol products in the U.S. is highly regulated, the special permit process allows companies to deliver new and more sustainable products to the public more quickly and with an equivalent level of safety than the standard rulemaking process.
For more information on shipping aerosol products in the U.S., please contact me at ngeorges@thehcpa.org. SPRAY
i As defined by the 49 CFR § 171.8
ii Aerosols are categorized in accordance with the 49 CFR § 173.115(l)
iii For example, the requirements for a 2P container can be found at the 49 CFR § 178.33
iv 49 CFR Part 107 Subpart B
v Requirements for the description can be found at 49 CFR § 107.105
vi Regulations pertaining to an application renewal are found in the 49 CFR § 107.109
vii 49 USC 5117(b)
viii link
Hello, everyone. This month, I’m starting a two-part series on the roles that water plays in causing or contributing to spray package corrosion. Water is in a formula as either an ingredient or a contaminant.
Steel alloys and aluminum alloys are both used to fabricate spray packages with and without coatings or laminate films. Steel alloys are in sheets and aluminum alloys can be either thin solid plugs (about the size of an ice hockey puck) or thin foils.
Water and metals are both thermodynamically unstable when in contact with each other. Thus, water can cause or contribute to package metal corrosion.
Water is a useful ingredient in a formula because it dissolves a wide range of other formula ingredients and also dissolves into a wide range of formula chemicals, solvents and propellants. For example, inorganic and organic salts, such as sodium chloride or sodium benzoate, dissolve in water.
Most gases dissolve in water, and some of these gases—such as carbon dioxide—react with water to form corrosive carbonic acid. Dimethyl ether (DME) propellant is water-soluble and small amounts of water will dissolve in HFC152a propellant, liquefied petroleum gas (LPG) propellants and most organic solvents.
Water and surfactants are used to form emulsions with water-insoluble ingredients. Emulsions can be either water in oil (oil-out or W/O emulsions), or oil in water (water-out or O/W emulsions).
Consequently, water is both a solvent and, in some instances, a corrosive species.
Water chemistry & properties
You probably remember from your first chemistry course that water molecules have one oxygen atom bonded to two hydrogen atoms (H2O). The valence electrons in water molecules are not shared equally between the hydrogen and oxygen atoms. Thus, one area of the water molecule is positively charged (the hydrogen end) and the other area is negatively charged (the oxygen end). The positive end is attracted to the negative charge associated with surface metal atom valence electrons.
Water’s small size also allows it to absorb into and migrate through interior package coatings and laminate films. Polymers swell when water absorbs into and diffuses through a polymer, thereby creating microscopic rivers through both polymer coatings and laminate films. Microscopic rivers that terminate at the package metal can cause both metal corrosion and polymer delamination, such as blisters.
Water & spray package corrosion
There is an approximate 62% probability of package-metal corrosion whenever corrosion testing is not conducted. Water molecules are electrochemically active, but water also dissociates into electrochemically active hydrogen ions and hydroxyl ions. Electrochemically active water and dissociated hydrogen ions can both remove electrons from spray package metals, thereby causing corrosion. In other words, in addition to being a solvent, water is also potentially a corrosive ingredient or contaminant. 
Liquid-water plays multiple roles in a formula and in package material corrosion (more on liquid-water in the next issue). Water’s various corrosion roles are it:
• Could be a corrosive formula ingredient
• Transports corrosive formula ingredients to the package metal
• Moves ions to/from corrosion sites to maintain the electrical balance between the corrosion sites and their surrounding areas
• Hydrates metal ions formed by corrosion
• Provides hydroxyl ions that bond with metal ions, forming visible corrosion, such as the various colors of rust observed on steel or the white and black corrosion on aluminum
• Migrates through package polymer coatings and laminate films to the package metal to cause metal corrosion and/or coating/laminate film corrosion, such as blistering
• Transforms coatings/laminate films into semi-permeable membranes that allow only specific formula ingredients to migrate through the coating/film to the package-metal
• Forms microscopic rivers of formula ingredients in a container coating or laminate film that could subsequently cause coating delamination and/or metal corrosion
• Is a solvent for the various corrosion inhibitors used to prevent and control spray package corrosion
Next time, we’ll discuss the mechanism for water corrosion and how water supports pitting corrosion, as well as how much water is needed to initiate spray package corrosion.
Thanks for your interest and I’ll see you in June. Contact me at 608-831-2076; rustdr@pairodocspro.com or from our two websites: pairodocspro.com and aristartec.com. SPRAY
California
Industry is preparing to provide the California Air Resources Board (CARB) with some training. The National Aerosol Association (NAA), Western Aerosol Information Bureau (WAIB), Household & Commercial Products Association (HCPA) and Personal Care Product Council (PCPC) will be in Sacramento on May 16–17 to present information to CARB staff on our products.
On May 16, CARB will be given an Aerosol 101. The last time we presented an Aerosol 101 to CARB was in 2018, before its rulemaking.
NAA & WAIB will lead the effort on the Aerosol 101, which will focus on all the components used in an aerosol. Featured will be valves, cans, propellant, solvents, caps, cartons, and other components necessary to develop an aerosol. In addition, Industry will focus on mandatory testing and regulatory requirements necessary to develop a safe and compliant aerosol product. CARB staff may ask for certain aerosol products to be highlighted as they have done in the past. Lastly, a summary of how an aerosol is manufactured will be reviewed.
On May 17, HCPA and PCPC will lead the industry effort to train the staff on non-aerosol products. Like the aerosol program, the non-aerosol products presentation will discuss components and focus on testing. Additionally, the training will cover the different non-aerosol forms and packaging that can be used, such as pumps, squeeze bottles, tubes, and tubs. CARB will likely request certain product categories be highlighted.
Participating from CARB will be the Planning, Enforcement and Laboratory divisions. Most likely, a representative from Legal and Management will also be present. It is beneficial for Industry to perform this type of training, as it is an excellent time to network and progress toward relationship-building, especially since we are currently not in a rulemaking situation (rulemaking always makes interaction more difficult).
Industry looks forward to the opportunity to interact with CARB staff on this issue.
Canada
On April 4, the Canadian Consumer Specialty Products Association (CCSPA), HCPA and NAA presented a 90-minute webinar to Industry. The webinar covered the Environment & Climate Change Canada (ECCC) regulation on volatile organic compound (VOC) concentration limits for certain products, commonly known as the Canadian Consumer Product VOC Regulation. Canada has been working on regulating VOCs in consumer products for more than 25 years and finally has a VOC regulation.
The regulation will become effective Jan. 1, 2024, for most products and effective Jan. 1, 2025, for disinfectant products. Remember, there is an unlimited sell-through for products produced before the effective date. This means that all product produced before Jan. 1, 2024, can be sold forever, given the product is properly date coded. The regulation is based on the 2010 Consumer Product VOC limits from the CARB regulation. The webinar covered the regulation, describing what is similar and what is not.
Even though ECCC tried to copy the CARB regulation, numerous differences remain. The biggest difference is in definitions. With CARB, we spent painstaking hours to get the definitions to be very specific, whereas with ECCC, some categories have little to no definition. This will make complying with the regulation more difficult. However, it will make enforcing the regulation even more difficult.
The webinar had close to 200 attendees. Numerous questions were asked and a great deal of valuable information was presented. The webinar was recorded and, if interested in reviewing it, please email—Simon Kinsman, Director of Regulatory Affairs, CCSPA: kinsmans@ccspa.org; Nicholas Georges, Senior VP, Scientific & International Affairs, HCPA: ngeorges@thehcpa.org; Doug Raymond, Industry Consultant, Raymond Regulatory Resources (3R), LLC: djraymond@me.com. SPRAY
Politics in the United Kingdom (UK) suffered a little bit of turmoil during 2022. We had three Prime Ministers, four Chancellors of the Exchequer and three Secretaries of State at the Dept. for the Environment, Food & Rural Affairs (DEFRA) and the Dept. for Business, Energy & Industrial Strategy (BEIS). Not satisfied with months of Ministerial “musical chairs,” the current Prime Minster decided in February to break up BEIS in to three separate departments: one for Business & Trade (DBT), one for Energy Security & Net Zero (DESNZ) and a third for Science, Innovation & Technology (DSIT).
For aerosol regulation, or at least the primary piece of regulation aerosol dispensers must conform to, we now have a whole new department to deal with and another new Secretary of State.
While all of this has been going on, the business of Government has not stopped. Following our departure from the European Union (EU), all Government departments are being asked to look at the regulations that were copied over into UK law when we left [in 2020], and to see if they are fit for purpose—all 2,400 of them. This is called the Retained EU Law (Revocation & Reform) Bill 2022 (REUL).
The Aerosol Dispenser Regulations are law in the UK. Interestingly, they contain references to other pieces of EU legislation such as Classification, Labeling & Packaging (CLP), which is reviewed under REUL. All such references will need to be updated, assuming a Great Britain (GB) equivalent can be agreed upon. The ministerial department responsible for aerosol regulation, the Office for Product Safety & Standards (OPSS), is also carrying out a much wider Product Safety Review, and the Aerosol Dispenser Regulations will be part of this. SPRAY
My early childhood education occurred in the 1990s, which meant I sat through a number of Drug Abuse Resistance Education (D.A.R.E.) classes. The D.A.R.E. program taught children how to resist the peer pressure of smoking cigarettes, drinking alcohol and taking drugs. However, now that I’m an adult, I’ve realized that inhalant abuse was rarely, if ever, mentioned—and it should have received more attention.
Inhalant abuse is the deliberate inhalation of common products, such as glue, nail polish remover, felt-tip pens and certain aerosol products, with the intention of getting high. Inhalant abusers use products that provide a quick “high” with rapid dissipation and minimal “hangover” symptoms.i
According to the National Institute on Drug Abuse (NIDA), nearly 21.7 million U.S. residents aged 12 and older have used inhalants at least once in their lives, and recent surveys show that 13.1% of eighth graders have used inhalants.ii According to the American Addiction Centers,iii inhalant abuse usually begins before tobacco, alcohol, marijuana or other substance abuse, which couldiv be because inhalants are legal to obtain and easy to acquire.
While there are a number of products that are abused as inhalants more often than aerosols,v the aerosol industry takes this problem very seriously, which has led to a voluntary warning on aerosol product labels about the potential dangers of intentionally misusing these products. Further, aerosol companies have implemented product stewardship efforts and many retailers will lock up products that are commonly abused.
The Household & Commercial Products Association (HCPA) also worked with aerosol member companies to create the Alliance for Consumer Education (ACE), a foundation aimed at addressing inhalant abuse through awareness and education. Inhalant abuse cases decreasedvi between the early 1990s and late 2000s; however, recent informationvii suggests they may be back on the rise.
In April 2021, Families United Against Inhalant Abuse (FUAIA) submitted a petitionviii to the Consumer Product Safety Commission (CPSC) to initiate a rulemaking to adopt a mandatory standard “to address the hazards associated with aerosol ‘duster’ products containing the chemical 1,1-difluoroethane, or any derivative thereof.” The petition asked CPSC to mandate a performance standard requiring manufacturers to add a bitterant agent (other than denatonium benzoate) to all aerosol duster products, as well as a warning statement that the product could kill the user if s/he breathes it. HCPA and other industry stakeholders submitted commentsix to CPSC opposing this petition, citing technical challenges with the proposed bitterant standard and inappropriate labeling, similar to that on cigarettes, which could actually encourage abuse.
In July 2022, CPSC publishedx a briefing package regarding the petition that recommended deferring the petition. While CPSC staff opposed the requests within the petition, it wanted to research other potential solutions that could reduce the intentional abuse of the aerosol duster product category.
With this intent, CPSC asked ASTM International to look into creating a new voluntary standard to minimize the risk of intentional misuse and abuse of aerosol duster products. ASTM held an exploratory call with various stakeholders—including CPSC staff, consumer advocates, behavioral scientists and industry representatives—to discuss potential options, such as enhanced labeling, consumer education, use of aversive agents and product delivery modification to reduce the likelihood of abuse.
Achieving a consensus when developing a voluntary standard is not an easy task, but it’s essential for industry to be a part of these conversations—especially in this case, because inhalant abuse is a behavioral problem. A standard should not deter the appropriate use of a product, nor should the standard draw attention to the fact that the product can be abused (in the instance of including an overly exaggerated warning label).
Any product can pose a hazard when it’s intentionally misused. Industry can’t solve this problem alone, but it can play a role, alongside other stakeholders, to educate the public about the dangers of intentionally misusing or abusing products. To learn more about what you can do to help, I D.A.R.E. you to contact me at ngeorges@thehcpa.org. SPRAY
i Williams, J.F., & Storck, M. (2007). Inhalant abuse. Pediatrics, 119(5), 1009–1017.
ii NIDA. 2020, May 28. Letter from the Director. Retrieved from here
iii American Addition Centers Editorial Staff. 2021, July 9. The Dangers of Inhalant Abuse. Retrieved from here
iv Kurtzman, T.L., Otsuka, K.N., & Wahl, R.A. (2001). Inhalant abuse by adolescents. Journal of Adolescent Health, 28(3), 170–180.
v Based on the Substance Abuse Mental Health Services Administration’s (SAMHSA), Center for Behavioral Health Statistics & Quality, National Survey on Drug Use & Health, 2013–2021.
vi Halliburton, A.E., & Bray, B.C. (2016). Long-term prevalence and demographic trends in U.S. adolescent inhalant use: Implications for clinicians and prevention scientists. Substance Use & Misuse, 51(3), 343–356.
vii Forrester, M.B. (2020). Computer & electronic duster spray inhalation (huffing) injuries managed at emergency departments. The American Journal of Drug & Alcohol Abuse, 46(2), 180–183.
viii FUAIA’s petition is available here
ix HCPA’s letter is available here
x CPSC’s briefing package is available here
Hello, everyone. One of the most difficult questions to answer about corrosion is why it is so random. For example, you may open and inspect 12 traditional aerosol container spray packages after six months of storage stability testing to find:
• Five corrosion-free packages
• One package with corrosion on the liquid product area
• Three packages with corrosion in the vapor area
• One package with a pit in the product phase
• One package with corrosion and pitting in the bottom crevice (bottom double seam)
• One leaking at a pit that perforated the container body
The formula in this example was from the same batch, so the chemical composition is the same; all the packages came from the same pallet (i.e., manufactured at the same time); and all the packages were all filled at the same time. Should you:
a) Ignore the corroded and leaking packages;
b) Put the program on hold; or
c) Something else?
It would be even more frustrating if you found 11 corroded packages and one pristine, corrosion-free package. Why isn’t corrosion more consistent?
Variability is the culprit that causes the inconsistency of the observed corrosion in the same product-package system. Variability can also cause the unexpected appearance of corrosion in a previously corrosion-free commercial product, particularly if the corrosion tests were conducted with the wrong parameters.
There are three generic types of variability:
1. Within each individual package—package variability
2. Within individual product and package production batches—within-lot variability
3. Between different product and package production batches—lot-to-lot variability
The main corrosion causing/contributing factors associated with the generic types of variability are:
1. Product chemical composition
2. Package coating, valve coating and laminate film morphology (e.g., thickness and adhesion)
3. Laminate film and coating chemical compositions
4. Package geometry
a) Aerosol valve crimps (crevices)
b) Package crimps (crevices)
c) Aerosol container double seams (crevices)
d) Aerosol container and laminated foil bag welds
It has been my experience that variability of the package and laminated foil metal chemistries typically do not have a significant effect on spray package corrosion. Consequently, variations in foil and package-metal chemistries are not included in the above list.
The four associated factors could cause corrosion either by themselves or in combination with one or more of the others. Consequently, the number of combined factors could be very great. For example, there are 5,040 possible combinations for all of the above associated factors.
Let’s briefly discuss the relationship between the associated factors and the inconsistency of the observed spray package corrosion.
1) Product chemical composition
Small changes in chemical composition, such as pH, fragrance concentration or amount of water, could transform a benign formula into a package eater. Variability is exacerbated by lot-to-lot variations in raw materials. There are also chemistry differences and variations in raw materials from different sources, even when the specification for the different sources is nominally the same.
2) Package & valve laminate/coating morphology
This pertains to thickness, adhesion and metal wettability. Laminate films and coatings have variable thickness on individual packages, among packages within the same lot and among packages from different lots. Variability in the metal cleaning process and the coating application process could also produce small areas on individual package surfaces that lead to delamination and metal corrosion under the film or coating. Coatings from different sources could also produce a narrower or wider thickness range, even when the specifications for the two sources are nominally identical.
3) Laminate film & coating chemical compositions
Variations in the chemistry of laminate films and coatings could cause variability in how the coating adheres to the substrate metal. Variability in adherence could cause laminate/coating delamination with subsequent metal corrosion under the coating.
4) Package geometry
Spray package crevices are formed when:
• Aerosol valves are crimped to the container curls
• Rolling the bottom of a laminated foil bag or tube to form a seal
• Seaming aerosol container tops and bottoms to the container body
Not all crevices are created equal. Some have a large opening with a short length, some have a small opening with a long length and so on. The ratio of the crevice opening to its length is referred to as its aspect ratio.
Crevice aspect ratios interact with a formula’s chemical composition and physical properties to determine if and when crevice corrosion will occur, if the crevice corrosion will be general corrosion with or without pitting corrosion and how fast pitting crevice corrosion will penetrate the package metal or laminated foil.
Spray packages typically have a range of crevice aspect ratios within individual production lots and between different production lots. Consequently, crevice corrosion—with or without pitting—does not occur in every spray package unless the product is extremely corrosive.
Spray package welds might also be vulnerable to coating corrosion, laminated film corrosion and foil and metal corrosion. Corrosion vulnerability is determined by the interaction between a formula’s chemical composition and the weld.
There are two ways to account for variability when conducting corrosion tests:
1. Develop a database on how variability affects package corrosion for each product family in your line of spray products
2. Design your corrosion tests to include:
a) A large number of replicate samples for each variable
b) Variables with package components from different production lots
c) Variables with different concentrations of potential corrosion-causing formula ingredients, such as water
The corrosion test could be a storage test, an electrochemical test or a combination of both. Skipping corrosion stability tests and conducting tests with the wrong parameters might result in surprise corrosion in the marketplace.
Thanks for your interest and I’ll see you in May. Contact me at 608-831-2076; rustdr@pairodocspro.com or from our two websites: pairodocspro.com and aristartec.com. SPRAY
