The Hidden Danger of Mixing Tylenol and Alcohol: What You Need to Know

Have you ever had a headache after a night out and instinctively reached for Tylenol (acetaminophen)? It seems harmless, right? After all, it’s just a simple painkiller, and many people use it without a second thought.

But combining Tylenol and alcohol can pose a serious risk to your liver—a risk that many people unknowingly take. While you might not feel the effects right away, the long-term damage can be irreversible.

So, let’s break it down: Why is this combination so dangerous? How much is too much? And what can you do to protect your liver?

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How the Liver Processes Tylenol and Alcohol

Your liver is one of the hardest-working organs in your body. It acts as a filter, breaking down everything you consume—from food and medications to alcohol and toxins.

• When you drink alcohol, your liver processes it first, turning it into acetaldehyde, a toxic substance that must be neutralized.
• When you take Tylenol, your liver also has to metabolize it. Normally, 90% of acetaminophen is safely broken down and excreted. But a small portion is converted into NAPQI—a highly toxic compound that the liver must neutralize using glutathione, an essential antioxidant.

🚨 The problem: When you drink alcohol, your liver is too busy breaking it down to properly handle Tylenol. This means more NAPQI builds up, leading to liver cell damage, inflammation, and, in severe cases, liver failure (Lee, 2008).

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How Much Tylenol and Alcohol Is Too Much?

Many people believe that only alcoholics or chronic pain patients are at risk, but even moderate drinkers can be affected.

Here’s what the research says:

• A few drinks + a standard dose of Tylenol (1,000 mg) can already stress the liver.
• Repeated alcohol use increases the production of certain liver enzymes that make Tylenol’s toxic byproducts even more dangerous (Du et al., 2020).
• People with pre-existing liver conditions (like non-alcoholic fatty liver disease (NAFLD)) are at an even higher risk (Kuffner et al., 2007).

👉 Bottom line: It doesn’t take excessive alcohol or frequent Tylenol use to put your liver at risk. Even occasional combinations can cause serious damage over time.

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The Long-Term Consequences

So what happens if you routinely mix Tylenol and alcohol?

🔴 Short-term effects:

• Increased stress on the liver
• Inflammation and mild liver enzyme elevations

⚠️ Long-term risks:

• Liver fibrosis (scarring of liver tissue)
• Cirrhosis (severe liver damage)
• Liver failure (in extreme cases, requiring a transplant)

A study published in Hepatology found that even therapeutic doses of acetaminophen (taken within recommended limits) can lead to acute liver failure when combined with alcohol (Davern et al., 2021).

🚨 The most alarming part? You may not feel symptoms until it’s too late. Liver damage is often silent until it reaches advanced stages.

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How to Protect Yourself

The good news is that this is completely preventable. Here’s how:

✅ Avoid Tylenol after drinking alcohol. Wait at least 12-24 hours before taking it.
✅ Check your medications. Many cold medicines and pain relievers contain hidden acetaminophen—don’t exceed the daily limit of 3,000 mg.
✅ If you drink regularly, talk to your doctor about safer pain relievers. Ibuprofen (Advil) or naproxen (Aleve) may be better options—but they come with their own risks, so always consult a healthcare professional.
✅ Monitor your liver health. If you take Tylenol often, ask your doctor about liver function tests to ensure your liver is handling it well.

🚫 One thing to avoid? Taking extra Tylenol to "speed up" alcohol recovery. It won’t help your hangover—it will only hurt your liver.

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Final Thoughts: Your Liver Deserves Better

Many of us watch our weight, monitor our heart health, and try to eat right. But how often do we think about our liver?

Liver failure isn’t just something that happens to alcoholics or people with severe health conditions. It can happen to anyone who unknowingly puts too much strain on their liver.

So next time you have a headache after drinking, think twice before reaching for Tylenol. Your liver works hard for you—take care of it in return.

💬 Have you ever mixed Tylenol and alcohol? Were you aware of these risks? Let’s discuss in the comments below!

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References

1. Lee, W.M. (2008). Acetaminophen-Related Hepatotoxicity. Clinical Gastroenterology and Hepatology.
2. Kuffner, E.K. et al. (2007). Effect of Maximal Daily Doses of Acetaminophen on the Liver of Alcoholics. JAMA Internal Medicine.
3. Du, K., Ramachandran, A., Jaeschke, H. (2020). The Role of Alcohol Consumption on Acetaminophen-Induced Liver Injury. Journal of Clinical and Translational Research.
4. Davern, T.J. et al. (2021). Acute Liver Injury with Therapeutic Doses of Acetaminophen. Hepatology.

Just Believing Can Change Your Body?! The Power of Belief, Proven by Science!

The Power of the Placebo Effect: How Belief Can Shape Our Health

Have you ever taken a pill, felt better almost instantly, only to find out later that it was just a sugar pill? That’s the placebo effect in action—our mind’s incredible ability to influence the body. It’s not just about fooling ourselves; it’s a real, measurable response that can impact pain levels, hormone balance, and even the immune system.

How the Brain Controls Pain

One of the best-known effects of placebos is pain relief. When we believe a treatment will work, our brain releases natural painkillers—endorphins and other chemicals similar to morphine. Studies using brain scans have shown that key areas like the anterior cingulate cortex and prefrontal cortex light up when a person expects relief, triggering the brain’s pain-relief system. This means that belief alone can activate the body’s own pain management tools, no medication needed.

Stress, Hormones, and the Placebo Effect

It’s not just pain—placebos can also affect hormones, particularly cortisol, the stress hormone. When we anticipate relief or healing, our body can dial down its stress response, leading to lower cortisol levels. Since cortisol influences metabolism, immune function, and overall well-being, this effect goes far beyond just "feeling better." In some studies, people who were given a placebo but believed they were taking real medication showed changes in their hormone levels—just from their expectations.

Can Placebos Influence the Immune System?

Surprisingly, yes! Research has shown that our immune system can be "trained" through conditioning, much like Pavlov’s famous dogs. In some experiments, people were given real immune-boosting or suppressing medications along with a harmless placebo. Over time, their bodies learned to associate the placebo with the real drug’s effects. Eventually, even when they received only the placebo, their immune system responded as if they had taken the actual medication. This suggests that our expectations and learned associations can shape how our body fights disease.

Mind, Body, and the Bigger Picture

What makes the placebo effect so fascinating is that it doesn’t just affect one system in isolation—it’s a full-body response. Changes in brain activity influence hormone production, which in turn affects the immune system. This challenges the old idea that the mind and body are separate. Instead, it highlights how closely our thoughts, emotions, and physical health are connected.

What This Means for Healthcare

Understanding the placebo effect has real-world benefits for medicine. The way a doctor talks to a patient, the environment of a hospital, or even the way a pill looks can all influence how effective a treatment feels. While doctors can’t (and shouldn’t) rely on placebos alone, they can use the power of expectation to enhance real medical treatments. This is especially useful in areas like pain management, mental health, and chronic illnesses where medication alone might not be enough.

Final Thoughts

The placebo effect is more than just "thinking yourself better"—it’s a real, biological process that affects pain, stress, and even immunity. It shows how powerful our beliefs and expectations can be in shaping our health. As science continues to explore this connection, we may find even more ways to use the mind’s influence to improve medical treatments and overall well-being.

The Truth About Earthing and Barefoot Walking: Science, Myths, and Real Benefits

Does Walking Barefoot Really Supercharge Your Health?

Barefoot walking—also known as earthing—has sparked a wave of health claims, from reducing inflammation to improving sleep. Some proponents say that walking barefoot allows you to absorb electrons from the Earth's surface, neutralizing free radicals and boosting well-being. Sounds intriguing, right?

But is there actual science behind it, or is this just another wellness trend? Let’s break it down logically, scientifically, and practically.

What Is Earthing, and What Are Its Claims?

The earthing theory suggests that direct contact with the ground allows the body to absorb beneficial electrons, which supposedly:

• Reduce inflammation
• Improve blood circulation
• Enhance sleep quality
• Lower stress levels

While these claims sound promising, scientific evidence remains weak. Although some small studies suggest benefits, there is no solid proof that “electron transfer” from the Earth directly impacts human health in the way proponents suggest.

The Real Benefits of Barefoot Walking (Backed by Science)

Even if the “electron transfer” theory is questionable, many people genuinely feel better after walking barefoot. But why? The benefits likely come from physical and biomechanical effects rather than a mysterious electrical charge.

✅ What Science Actually Supports:

• Strengthens Foot Muscles – Modern shoes provide cushioning and support, which can weaken foot muscles over time. Walking barefoot engages the natural arches and stabilizing muscles of the foot, making them stronger.
• Improves Posture & Joint Health – Shoes alter natural walking patterns, sometimes causing knee or back strain. Barefoot walking restores a natural gait, reducing unnecessary stress on the joints.
• Enhances Sensory Feedback & Balance – The soles of your feet are packed with nerve endings. Walking barefoot stimulates these nerves, improving balance and coordination, which is particularly important as we age.
• Boosts Circulation – Without restrictive footwear, the feet move more actively, encouraging better blood flow and reducing stiffness or cold feet.
• Reduces Stress & Connects You to Nature – Many of the benefits of “earthing” may simply come from being outdoors, breathing fresh air, and moving naturally—all of which lower cortisol (the stress hormone) and improve mood.

What About Shoes? Are They Bad for Us?

Not necessarily! Walking with shoes still provides excellent health benefits, but different types of footwear impact the way we walk:

• Traditional cushioned shoes – Provide comfort and protection but can weaken foot muscles over time.
• Minimalist shoes – Offer a great balance by protecting the feet while allowing natural movement.
• Barefoot walking – Strengthens feet, enhances balance, and improves joint alignment but requires safe surfaces to avoid injury.

Are “Earthing Shoes” Worth It?

Some companies sell “grounding shoes” with carbon-infused soles or copper plates, claiming they allow you to absorb the Earth’s electrons while still wearing shoes.

Do they work? In theory? Maybe. In reality? It’s likely just marketing hype.

Instead of spending money on special footwear, you’d get more real benefits by walking naturally—barefoot or in comfortable, flexible shoes.

What’s the Best Way to Walk for Health?

The key to reaping the benefits of walking isn’t about electrons—it’s about movement. Here’s what you can do:

• Try barefoot walking on safe surfaces (grass, sand, or smooth dirt) to strengthen foot muscles and improve balance.
• Choose minimalist shoes if you want foot freedom with some protection.
• Just keep walking! Whether barefoot or in shoes, regular walking is one of the best things you can do for your health.

Final Thoughts: Science, Health & Common Sense

Scientific research is still catching up on whether grounding has real measurable effects on health. But what we do know is that movement, fresh air, and engaging with nature all boost well-being.

So next time you hear about “earthing” or “electron therapy,” don’t stress over the science—just go for a walk. The real magic isn’t in the marketing; it’s in the movement.

Happy walking! 👣💚

The Hidden Dangers of Microwaving Oily Food in Plastic Containers

Let me ask you a question: How many of you use plastic containers to heat your food in the microwave? Probably most of us, right? It’s super convenient. You take your leftovers, pop them in the microwave, and in a couple of minutes—boom! Ready to eat.

But what if I told you that some of those plastic containers, even the microwave-safe ones, might not be as safe as you think? Especially when you’re heating oily or fatty foods.

Today, I want to talk about:

1. Why heating oily food in plastic can be risky
2. What actually happens when plastic gets too hot
3. Simple ways to stay safe without giving up convenience

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1. Why Heating Oily Food in Plastic Can Be Risky

So, let’s start with the basics. Most food containers we use are made of polypropylene, or PP. It’s one of the safest plastics out there—BPA-free, sturdy, and resistant to heat. That’s why many PP containers have a "microwave-safe" label.

But here’s the problem: Oily and fatty foods heat up much higher than water-based foods in the microwave.

• If you microwave soup or rice, it usually won’t go past 100°C because that’s the boiling point of water.
• But if you microwave something oily—like cheese, butter, curry, or meat—the temperature can rise to 150°C or more.
• That’s a big deal because PP plastic starts softening around 120°C and can break down at higher temperatures.

That means if you’re microwaving something really greasy in a plastic container, it might not just be heating your food—it could also be damaging the plastic itself.

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2. What Happens When Plastic Gets Too Hot?

So, what happens when a PP container gets hotter than it should?

First, it can start to soften or warp. If you’ve ever pulled a plastic container out of the microwave and noticed it’s misshapen or the lid no longer fits, that’s a sign the plastic has been overheated.

But more importantly, it can start releasing chemicals into your food.

Even though PP is one of the safer plastics, it still contains stabilizers and additives to make it strong and flexible. When exposed to high heat, especially from fatty foods, some of those chemicals can leach into your food.

And while one or two times might not be a big deal, if you keep reheating oily foods in plastic every day, those chemicals could slowly build up in your system.

Now, am I saying you’re going to get sick instantly from heating your leftover pizza in plastic? No. But why take the risk when there are easy ways to avoid it?

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3. Simple Ways to Stay Safe

The good news? You don’t have to throw away all your plastic containers. But a few small changes can make a big difference.

1. Use the Right Containers

✔ If you must use plastic, make sure it’s actually microwave-safe—not all PP containers are.
✔ Check for any warping, scratches, or discoloration—these are signs the plastic is breaking down.
✔ If your plastic container feels soft or changes shape after microwaving, it’s time to replace it.

2. Be Careful with Oily Foods

✔ Avoid microwaving foods with a lot of oil, butter, or cheese in plastic containers.
✔ Instead, transfer it to a glass or ceramic dish before heating.
✔ If you must use plastic, heat in short intervals (30 seconds, then stir) instead of blasting it for minutes straight.

3. Keep Your Microwave Temperature Under Control

✔ Reduce your microwave power setting to 50–70% for a gentler heat.
✔ Loosely cover the container, but don’t seal it too tight—trapped heat can make temperatures skyrocket.

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Conclusion: Small Changes, Big Impact

To wrap things up, PP plastic is convenient, but it’s not perfect. It works great for storing food and even reheating most things, but when it comes to oily foods, it’s better to be cautious.

Here’s what to remember:

1. Oily foods heat up much hotter than water-based foods, sometimes over 150°C, which can damage PP plastic.
2. Overheated plastic can release chemicals into your food.
3. A simple switch to glass or ceramic for reheating fatty foods can help you avoid unnecessary risks.

So next time you’re about to microwave that buttered popcorn, creamy pasta, or greasy leftovers, take a second to think—should I really use this plastic container?

Making small changes now can help protect your health in the long run.

Thanks and I hope this helps you make safer choices in the kitchen!

References

1. Lithner, D., Larsson, Å., & Dave, G. (2011). "Environmental and health hazard ranking of common plastic polymers based on chemical composition." Science of the Total Environment, 409(18), 3309-3324.

   • This study discusses the chemical additives in plastics and their potential risks.

2. Muncke, J. (2009). "Exposure to endocrine-disrupting compounds via the food chain: Is packaging a relevant source?" Science of the Total Environment, 407(16), 4549-4559.

   • Highlights how food packaging, including microwaved plastic, may contribute to chemical exposure.

3. Grob, K., et al. (2006). "Food contamination with organic materials from packaging materials." Food Additives & Contaminants, 23(11), 1012-1028.

   • Examines chemical migration from plastics into food at elevated temperatures.

4. Peixoto, R. R. A., et al. (2019). "Evaluation of specific migration of substances from polypropylene food containers." Food Control, 102, 122-129.

   • Studies how heating affects the migration of substances from PP containers.

EASY 10 Ways To Cut Down Plastic Use

The use of plastic containers has increased significantly as the number of delivery foods and small-batch packaging has increased.

Plastics take a very long time to decompose. And since it is known that microplastics and substances from plastics have adverse effects on humans as well as marine life, there are many people who are campaigning to reduce plastics.

I am also working hard personally to reduce the use of plastic by not using plastic bags at the mart and reducing food delivery.

Plastic waste from life

So, here are 10 simple ways you can use plastic very easily.

1. Use a personal cup(tumbler) at café
2. Reduce the use of plastic straws and sip sticks
3. Use Eco Bags at mart
4. Purchase label-free products(bottled water and beverages)
5. Use reusable food containers
6. Refuse disposable items for food delivery
7. Make online-orders together
8. Boycott overpackaged products and send a boycott message to the company
9. Reduce unnecessary use of plastic wrap
10. Use bundled products rather than individual packaging

These above are 10 ways that we can easily apply in our daily lives to help reduce the use of plastics.

I think there are many ways that we can practice if you pay a little attention. A small effort will be required for the environment in which we will live and the environment in which our future generations will live.

[Learning Korean]Emotion Pub? gamseongjujeom?

Gamseongjujeom(감성주점) is one of the hottest words in South Korea now, because of COVID19. As many young people go to there and do close-contact each other, that behavior causes COVID19 spread.

And then what is Gamseongjujeom?

Gamseong literally means emotion and Jujeom is where alcoholic drinks are sold like a pub. But the meaning from the words is twisted and changed with other meaning.

GamseongJujeom can be defined like below

In the form of a pub where young people, such as mainly early 20s, go , it is similar to a regular pub, but with music and stage that can be danced, dance between tables if there is no space to dance. This is a pub that can be used as an intermediate form between a club and a general pub and they usually go there to find a new partner.

GamseongJujeom, what is the difference from a general pub?

According to Korean Law(ENFORCEMENT DECREE OF THE FOOD SANITATION ACT), the food service business can be divided into six categories.

Food service business:
(a) Rest restaurant business: Business of cooking and selling mainly tea, ice cream, etc., or cooking and selling foods in fast food stores or snack bars, where drinking is not allowed: Provided, That the same shall not apply where water is poured into instant cup noodle, instant tea or other foods in the places which sell foods such as convenience stores, supermarkets and rest areas
(b) General restaurant business: Business of cooking and selling foods, where drinking accompanied with meals is allowed;
(c) Karaoke bar business: Business of cooking and selling mainly alcoholic beverages, where customers are allowed to sing;
(d) Entertainment bar business: Business of cooking and selling mainly alcoholic beverages, where workers engaged in entertainment may be employed or entertainment facilities may be established, and customers may sing or dance;
(e) Catering service business: Business of cooking and providing foods in facilities providing meals, in accordance with a contract concluded with persons who establish and operate facilities providing meals;
(f) Bakery business: Business of manufacturing and selling mainly bread, rice cake, snacks, etc., where drinking is not allowed.

In South Korea, a pub is usually a General restaurant business but in a nutshell, a pub with dance is a Entertainment bar business. And the businesses are subjected to different tax rate.

[Learn Korean] Mini Signs that you can see at KTX

KTX(Korea Train eXpress) is the fastest train system in South Korea. And its railways are connected everywhere in South Korea from Seoul.

So if you arrive at the Incheon airport and you plan to travel Korean local city, it is one of the best choices to take the KTX train. As it takes two and half hours from Seoul to Busan.

In KTX train, you can find mini signs that has long and meaningful Korean words but also has just short English translation.

Let's see some of them and learn Korean.

1. The first mini sign is here. You will probably find it on the window frame or on window.
Luckily there is a simple pictogram with it but no translation in English. And the pictogram cannot express what the words mean.

창문의 블라인드 손잡이를 아래로 끌어내리면 햇빛을 가릴 수 있습니다.

Although the pictogram just says that there is a window blind being able to go down, Korean words say it in some different way.

You can block the sunlight by dragging the window blind's handle down.

I have no idea why they write it like that. Too long and too kind. It feels like a window blind is not usual thing here.

2. Second, about KTX Mini Library. If you have a first class ticket of KTX, you can see the KTX Mini Library near the entrance of the first class cabin. And below the simple mini sign, there is some words that say something.

[부탁합니다] 책을 보신 후 다음 승객을 위해 KTX 미니도서관에 놓아주시기 바랍니다.

There is only Korean language books, so maybe someone does not think that foreign people do not use the library, that's why the sentence is not translated.

After reading the book, please return it at the KTX Mini Library for the next passenger.

 3. There is a hidden useful button that even some Koreans don't know about it. The button is above the cabin door and the function of the button is 'open the door for 3 minutes'. When you get on the train, you can push the button for the people behind you like a 'I -well-know-the KTX' person.

3분열림버튼(Open the door for 3 minutes)

4. Last. You can see the sign above. And it is just like the international standard sign of no smoking. But there is more.

화장실에서 흡연 시 화재감지 장치가 작동하여 열차가 비상정차 됩니다.

In English,

When smoking in the bathroom, the fire detection device operates, and the train stops.

I don't know why the Korean sentence below the sign is not translated. Anyway I'm sure that even smokers do not want to stop the train accidentally.

What would you do if you lost your shoes at the Korean restaurant in Korea?

In South Korea, there are many Korean style restaurants where you should leave your shoes by the door area to go to a table for food and service.

Usually the system is not a problem but when there are crowded, some bad incidents are happened.

What is the events? LOSING SHOES.

It happened barely. When bad luck hits you, it can be you and your shoes can be disappeared without any clue.

What if your shoes are disappeared at that kind of Korean restaurant?

What will you do? What should you do?

Maybe the owner of the restaurant can say that he has no responsibility for your shoes. Or  there can be the board on the door or on the wall near the counter that says 'Keep your shoes by yourself to prevent loss and stolen'.

And possibly if the owner is kind and you are lucky enough, he will provide you a pair of slipper(slip-on shoes) for free so you can leave the restaurant.

Do you think the slipper is the best happy ending you can have?

I don't think so.

In Korea, there are laws to protect consumers. In this kind of case, there is Commercial Act about hospitality business.

The hospitality business is in the business of making transactions by theaters, hotels, restaurants, or other facilities used by the public. And anyone who engages in this business is called a hospitality service provider.

The Commercial Act regulates the liability of hospitality service providers.

Commercial Act Article 152 (Liability of Hospitality Service Providers)
(1) Unless a hospitality service provider proves that he/she has not been negligent in giving due care in the custody of articles deposited from his/her guests to him/her or his/her employee, the hospitality service provider shall be liable for damage resulting from the loss of or damage to the articles kept in his/her custody.
(2) A hospitality service provider shall be liable for damage for the loss of or damage to portable goods brought into his/her establishments, even if not particularly deposited by the guest, when it is due to the lack of due care of the business entity or any of his/her employees.
(3) No hospitality service provider shall be exonerated from liability under paragraphs (1) and (2), even if he/she has informed that he/she is not liable for the loss of or damage to the portable goods of guests.

Yes, it says the hospitality service providers shall be liable for the loss of or damage to the articles kept in his/her custody.

So when you take off your shoes and put them at the door and go to a table, it is thought that you and the owner of the restaurant make a contract containing that the owner keeps your belongs(shoes).

Even though the owner notices to the customers that no responsibility for loss and stolen, the owner's liability is not waived.

Now you know your right, and you can say to the owner like that

"Please, take your responsibility that is gave by Commercial Act Article 152. And give me back my shoes or show me the money!"

Of course, there is the statute of limitation for period for the liability. The period is 6 months.

Which means you should act for your right in 6 month after the incident.

And this law can be applied on car damage/stolen at parking lot where the owner controls.

Surface Preparations For Powder Coating

Surface preparation is one of the most important factors in powder coatings as well as liquid coatings and almost all coatings.

Surface preparation is often expressed as surface pretreatment or surface treatment.

Surface pretreatment for painting can be approached in two main ways.

1. Surface cleanliness

When we think about the surface preparation, there is a famous well-known standard for it. It is ISO 8501(Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness).

And its title said 'surface cleanliness'. Because this is an important factor in surface preparation, and most surface preparation methods are used to make the surface clean.

2. Improving Adhesion

In the painting preparation process, the surface pre-treatment through the cleaning or post-cleaning process usually involves a process to increase the adhesion between the coating and the substrate. One way to increase adhesion is to increase the surface area physically and chemically, such as by shot/grit blasting or conversion coating.

Anyway, surface treatment for painting determines about 60-80% of the paint quality.

Spray type process line of Surface Preparation

Let's take a look at surface pretreatment methods that are mainly used in powder coating.

1. Shot/Grit Blasting

Abrasive blasting is a more appropriate and broad term, but in the field, sandblasting and shot blasting are also used.

Short or grit is a term that describes the form of media used for blasting.

Sandblasting use sand to blast, so it is called sandblasting.

Abrasive blasting is an effective method that has been used for a long time.

The media particles are collided with the surface of the material by using air pressure or centrifugal force to remove rust or foreign substances on the surface. And a profile is formed on the surface due to the collision, which increases the surface area and thereby affects the adhesion.

2. Degrease

In powder coating and liquid coating field, the surface is prepared by just removing foreign substances such as oil and grease on the surface with solvent or detergent, to be coated.

Most of the metal is contaminated with oil because the processing oil or lubricating oil is usually used when the metal goes through the forming process.

Such the oils can decrease the adhesion between the surface of the material and the coating film, or cause defects such as cratering.

Degreasing methods includes using alkaline detergent, acid solution and solvent.

3. Conversion Coating

Conversion coating is slightly difficult to get the concept of it. But it is easy if you think of the plating on the material surface with chemical reaction. The method combines the surface of the material with other metals to improve the coating adhesion and corrosion resistance.

Conversion coating is largely divided into Phsphate and Chromate. Phosphating conversion coating is mainly used for iron(steel) materials, and chromate is used for aluminum(alloy) materials.

In recent years, various conversion coating agents such as Zirconium and non-chrome have come out, and these various conversion coating agents are being developed to reduce environmental pollution, improve adhesion and corrosion resistance.

4. Acid Cleaning

Acid treatment, called pickling, is a method of removing rust or mill scale from surfaces using a strong acid solution.



The preparation methods is used alone or also in combination.

For example, the surface preparation process for the automotive wheel is simply like below.

Blasting -> Degreasing -> Rinsing -> Acid Cleaning -> Rinsing -> Conversion Coating -> Rinsing -> DI water Rinsing

Continuously surface preparation methods are applied in various ways according to environmental regulations, materials to be coated, and pretreatment efficiency, and are being developed in various ways.
And we will see them in detail later.


LINK: Korean Version of This Post([도장 전처리]분체도장에 주로 사용되는 전처리방법들)

[Paint Inspection]MEK rubbing test method and its limitations

Among the test methods, the most popular and easy to use test method for determining the degree of curing of the coating film would be the MEK rub test.

The term of MEK Rub Test is used much however Solvent Rub Test is the accurate term for MEK Rub Test.

It is called 'MEK Rub Test' because MEK is a strong solvent and mainly used among solvents, since the solvent-MEK is mainly used to evaluate the degree of cure of inorganic Silicate Inorganic Zinc Rich Primer, it is usually called more as MEK rub test than Solvent Rub Test.

Pros and Cons of MEK Rub Test

Pros: Easy, Quick, Simple
Cons: Comparative Evaluation, Lack of Reproducibility

Specifications of Solvent Rub Test

• ASTM D5402 Standard Practice for Assessing the Solvent Resistance of Organic Coatings Using Solvent Rubs
• ASTM D4752 Standard Practice for Measuring MEK Resistance of Ethyl Silicate(Inorganic) Zinc-Rich Primers by Solvent Rub

ASTM D5402 is a standard for evaluating the solvent resistance of organic paints, and ASTM D4752 is a standard for measuring the degree of curing of inorganic zinc primers through the solvent (MEK).

Solvent Rub Test Method (MEK Rub Test Method)

1. Prepare a fully cured control panel and a test panel.
2. Moisten a cotton swab or white cloth with a solvent(MEK) and rub it back and forth at a constant pressure.
3. Test on both panels under identical conditions.
4. Determine the degree of cure by comparing the changed state of gloss, coating loss, etc.

Limitations of Solvent Rubbing Test

MEK rubbing testing has limitations due to its test methods.

In the case of ASTM D4752 listed above, the standard provides a reference table to determine the degree of cure, but when used to determine the degree of cure of a organic paint, a generally comparable standard is required. So the disadvantage here is that the degree of cure must be determined by comparison between the fully-controlled panel and test panel.

In addition, when doing MEK test, it is necessary to know the type of paint. This is because some resins have weak solvent resistance to MEK or some solvent, and so even after proper curing, the gloss, film loss, or softening of the coating may be as if uncured.

The aggressive of solvents

MEK, Acetone >>>>>>> Xylene, Toluene

Depending on the resin type and requirements, solvent selection is also required, but MEK is usually used a lot.

One of the limitations of the MEK test is that it is a test conducted by a human.

As a result, test results may vary due to differences in rubbing speed, force, lasting time and other human factors.

(The pressing force, speed, and rubbing distance can be specified in the above ASTM standards or test requirements.)

However, it is widely used as a very useful test method to easily and quickly determine the degree of curing in the field and the laboratory, and test equipment with minimal human factor has been developed and used for more accurate testing in the laboratory.

TGIC Hazards Used as Powder Coating Curing Agent

Harmful Substances in Our Lives that We Do Not Know Well: TGIC (triglycidyl isocyanurate)

Mutagen! Organ Damage!

There are many harmful substances that we use but we do not know well in our lives.

Among them, we will learn about Triglycidyl Isocyanurate (TGIC) which is mainly used as a hardener.
TGIC is a raw material that is widely used as a curing agent in powder coatings using polyester resins.
The hardener is combined with the resin, which plays a role in the performance of the paint as a film.

There are two types of hardeners used in polyester resin powder coatings, a TGIC-free type hardener and a TGIC type hardener.

Powder coatings of polyester resins are wildly used in

• For indoor, industrial machines, interiors, furniture, home appliances, office furniture, electrical appliances, etc.
• For outdoor use, mobile parts, achitectural material such as fasade and window frames, electric control box, outdoor air-conditioner unit, etc.

Acute toxicity(GHS pictogram)

So now on, let's take a closer look at the harmfulness of TGIC.

• TGIC can be absorbed by the body through the skin. In addition, it can be introduced through the mouth or breath, and dust containing TGIC is often introduced into the body through breathing.
• If swallowed or inholed TGIC, it could damage the lungs, kidneys and digestive system.
• The more contact with TGIC, the more sensitive the body is to TGIC.
• TGIC can cause serious eye damage.
• Animal testing has shown that TGIC can cause genetic modifications.
• Blisters, itching, and swelling were observed in workers who used powder coatings or hardeners containing TGIC, asthma and leukocytosis in exposed powder spray workers, and atopic symptoms in exposed skin.
• Human tests of cancer patients showed toxic symptoms such as decreased spinal cord activity (blood production), dizziness, vomiting, white blood cell reduction, and partial hair loss.

There is still a lack of long-term testing for the effects of TGIC on the human body. So in addition to the hazards mentioned above, there may be more serious effects.

Health Hazard(GHS pictogram)

So please be aware of the following points when handling TGIC.

Where powder coatings containing TGIC are used,

1. Paint booths with limited access should be used.
2. Vacuums / suction cleaners should be used for cleaning to minimize dust.
3. If you use a powder coating with TGIC, you will need to wear personal protective equipment such as gloves, dustproof clothing, safety glasses and a dust mask.
4. Personal protective equipment must be worn in all processes of handling powdercoatings that containing TGIC.

To deal with TGIC as a raw material,

1. Vacuums cleaners should be used to minimize dust generation.
2. The process of handling raw materials must be designed to be sealed and automated as possible to minimize human access.
3. Dust collectors / suction facilities are provided throughout the workplace so that dust can be removed immediately.

Wherever TGIC is handled, safety training for personnel, training to wear personal protective equipment and provision of personal protective equipment should be provided and done.

TGIC should be more careful as its toxicity persists even after commercialization with raw materials.

Products containing TGIC are prohibited for use in some parts of China as well as in Europe.

Many countries are aware of the toxicity of TGIC, and regulations on safety training and dust collection facilities for workers are being implemented. Companies that used products containing TGIC are increasingly demanding TGIC-free products.

Reference :

1. NICNAS https://www.nicnas.gov.au/chemical-information/factsheets/chemical-name/triglycidylisocyanurate-tgic
2. WHO Concise International Chemical Assessment Document 8 TRIGLYCIDYL ISOCYANURATE

Link of the post in Korean: 유전자 변형! 장기손상! 유해물질 : TGIC(트리글리시딜 이소시아누레이트)