Finishing materials are used to complete the exterior part of a building. They serve to enhance the aesthetic features of the building as well as protect the surface from external impacts. The materials are categorized into interior and exterior material, roofing material, etc., according to their usage. Since finishing materials are exposed — thus visible and touchable — unlike structural materials, the context of a building can vary depending on which finishing material is used.

Jooshin Co., Ltd. specializes in producing and selling finishing materials optimized for various purposes, such as for exterior walls of buildings, interior, roofs, and so on. Founded in 2001, the company has worked on product development continuously and, as a result, grown into a small giant with more than 40 patents today. Behind the impressive performance, CEO Myeong-Woo Yoo’s management philosophy, change and innovation, lies.

▲ CEO Myeong-Woo Yoo explaining the management philosophy of Jooshin Co., Ltd.

“Jooshin does not develop a product unless a patent is a prerequisite. It means that we focus only on high value-added products that go beyond conventional products with new non-existent ideas. The conditions in the market change from day to day and demands from clients are becoming more challenging. That is why Jooshin aims to create new trends by grasping and responding to market changes.”

The persistent efforts did bear fruits. Currently, Jooshin Co., Ltd. stands out as a company leading the top 1% of roof and exterior market in Korea. In 2016, the company developed roof and exterior materials that adopt POSCO steel plate and SUPER ALCOSTA, a highly corrosion and heat resistant aluminum plated steel plate, and participated in major public projects, such as the Pyeongchang Winter Olympic Stadium and Incheon International Airport. At the beginning of this year, seven of the company’s products were selected as POSCO INNOVILT products. As a result, it has become a single company with the most INNOVILT products. Among them, ZintaMax, the main product of the company, is the subject today.

l ZintaMax, The Beauty Imposed by Variations of Straight Lines

ZintaMax is a block-shaped finishing material that stretches out in a straight line. It can be installed on the exterior and interior walls of the building, on the ceiling, and all other places, excluding the roof. Since each finishing material has different strengths and employs different construction methods depending on where it is adopted, there aren’t many products that can be used for multiple purposes. On the other hand, ZintaMax is highly versatile as it can be installed anywhere a finishing material is needed with high strength and simple construction method thanks to PosMAC, its raw material.

Then what about the design? At first glance, you might think that simple straight lines and curves are all about the product, but many different kinds of design can be created by using ZintaMax. Its sizing can be flexible to fit for various purposes. For example, if you drill a hole and install it with lighting, it transforms into a decent interior material.

And this is not all. By utilizing the color printed steel product, which is a trend in the market these days, it is also possible to produce ZintaMax in diverse colors and patterns, such as yellow, blue, wood, and marble. POSCO’s PosMAC, the raw material of ZintaMax, goes under surface treatment at POSCO C&C and is then sent to Jooshin to be fabricated into the product. POSCO’s Jin-Ah Kim explained, “The color printed steel of POSCO C&C embodies the features of other materials almost perfectly so there is little difference in appearance from actual wood or marble. It is an Sustainable material that can realize the interior and exterior desired by clients without damaging nature.”

Another thing, with POSCO C&C’s Multi-Color Steel Sheet, more diverse designs can be created. Multi-Color Steel Sheet is a color steel product where multiple colors can be expressed simultaneously on a single-coil, and POSCO C&C is the sole domestic manufacturer. POSCO’s Jin-Ah Kim said, “When ZintaMax is made with these Multi-Color Steel Sheets, all the colors of the convex and concave parts can be expressed differently. The distinct and specialized design can satisfy the diverse needs of clients.”

l Design, Safety, Durability: 3-in-1!

ZintaMax, an innovative item in the conventional metal finishing material market, was born through collaboration between Jooshin Co., Ltd., and POSCO. While carrying out a joint study in 2019 regarding steel construction materials, Jooshin Co., Ltd., POSCO, and POSCO C&C came together to develop a finishing material with a unique design. Jooshin invested in facilities for production, while POSCO and POSCO C&C developed new colors and designs for the products. “No matter how good silk is, it can not be called a garment without proper altering. The case is the same here. Excellent products like the multi-color steel sheet and PosMAC will truly be acknowledged only when there are practical technologies to apply to buildings. POSCO and Jooshin worked on the details together, and ZintaMax is the result.”

Finishing material should be safe as well as aesthetically pleasing. How strong is ZintaMax against external stimuli, such as fire or corrosion? CEO Yoo proudly explained, “ZintaMax does not burn in fire and also has aesthetic features as well. These days, the incombustibility of finishing materials, like the roof and exterior materials, is being emphasized due to a series of fires that broke out in warehouses. Relevant laws have also been revised, banning the use of flammable finishing materials in buildings above three floors. ZintaMax is safe to use because it is made of POSCO C&C incombustible colored steel that does not ignite at high temperatures and generate less smoke and harmful gases.”

Since it is made of POSCO steel, the finishing material is also highly resistant to corrosion. “PosMAC, the raw material of ZintaMax, has a stronger plating layer than conventional galvanized steel, so it is highly wear-resistant and scratch-resistant. Generally, the cutting surfaces or parts that are scratched during installation gather rust. However, PosMAC has an oxide layer called Simonkolleite made by plating zinc with magnesium and aluminum. This layer prevents the corrosion of the surface as well as the machined parts.”

l INNOVILT ZintaMax: How Are They Made?

The aesthetic yet safe and durable ZintaMax. How is it made? The entire process was walked along with an explanation from Jae-Wook Yoo. He said, “The manufacturing process of ZintaMax is largely divided into three stages. The large steel coil that you can see over there is color printed steel made of PosMAC. POSCO’s PosMAC is coated at POSCO C&C and delivered here to Jooshin in coil shapes. The coil-shaped steel sheets go under an Uncoiler to make them flat. Next, they pass through the forming roll where they are shaped into desired forms. When they are put into the roller, the bumpy shapes of the ZintaMax are complete.” The manufacturing process was as simple as its construction method. The shortened construction period could also help reduce cost.

What is unique is that most of these processes are performed directly on site. It is a differentiated part from general finishing materials that are transported to the construction site after making finished products at the factory. Director Yoo Jae-wook said, “Because we look at the building to be applied in the field and make it right away, it can be constructed without any length limitation.”

l You Can See ZintaMax Here!

Buildings adopting ZintaMax can easily be found around us. Starbucks, the mega-franchise coffee shop, is an example. The recent Starbucks coffee shop that opened in Gimhae adopted a wooden pattern ZintaMax to the front of its exterior wall. On the outside, it looks just like wood. “If the walls were made with real wood, the processing cost would have been high, and there must have been a fair amount of logging.” On the side and back walls of the coffee shop building, a dark-gray zinc pattern ZintaMax was applied. The entire building demonstrates the attractive features of the color printed steel sheets that can embody all materials and colors without any restrictions. The charms of ZintaMax can also be seen in other various buildings, including the Gwangyang POSCO Childcare Center and the Sharp Gallery in Seoul.

Export prospects also look bright. Jae-Wook Yoo said, “We have received positive responses from Southeast Asian clients for suggesting wooden patterned ZintaMax. ZintaMax, which has both the durability and design features of steel, will serve as a definite alternative in Southern Asia where the deformation of construction wood is frequent due to hot weather.” He also added, “Although all discussions have been temporarily suspended due to the COVID-19 pandemic, we expect tangible results soon.”

l Jooshin & POSCO, “Standing Out by Working Together”

If there is a single word that binds Jooshin and POSCO, it would be “First Mover”. Jooshin has been expanding the use of not only PosMAC but also PosPVD, a next-generation surface-treated steel plate developed by POSCO, in the steel construction material market. Regarding the cooperation between the two companies, Jae-Wook Yoo stated, “Working with POSCO Group, I could feel the passion that the entire group has for developing new products. They are eager to lead the market and do not hesitate to try out different attempts. Just like a pioneering leader. Such features fit well with the identity of Jooshin, which is to pursue creativity and innovation.”

Jin-Ah Kim also responded, “Whenever we find clients who are worried about how to construct with colored steel, we show them ZintaMax. ZintaMax is proactively applied to projects of POSCO E&C, and so it is not an exaggeration to say that it is growing together with POSCO Group. Jooshin always stimulates us with new ideas making us wonder where else we can use POSCO products in such a variety of ways.”

With the INNOVILT Alliance, the synergy shown by the two companies is expected to expand further. Both companies are working together on the R&D of a louver^* with non-flammable performance. Conventional wooden louvers are flame-retardant, but not non-flammable, so if this collaboration is successful, a safer louver can be introduced to the market. ^*louver: interior wood material used to prevent glare.

CEO Myeong-Woo Yoo commented that INNOVILT Alliance is a strategy of going together. At the end of the interview, he said, ”I’m excited for POSCO’s challenge to create a new structure with partner companies. Though the way of going together might not be easy, I am looking forward to the future that Jooshin and POSCO will create together.”

※ This content was produced in compliance with the COVID-19 quarantine guidelines before ‘Social Distancing Step 2.5’ was imposed.

After the Busan fire, Korean government banned combustible finishing materials for buildings over 30 stories (120m) to prevent similar mass fires. Despite the new legislation, mass fires continued — even in smaller buildings.

After the devastating hospital fire in Miryang last year, the government is now set to enact new legislation mandating non-combustible finish materials for buildings over 3 stories. For the construction industry, the new law is practically a ban on all combustible materials.

Now, POSCO C&C is addressing the industry and the government concerns with a new innovative product: a non-flammable color steel sheet. POSCO Newsroom reports.

l Hardly Burns, Hardly Fumes

On July 5, POSCO C&C(POSCO Coated & Color Steel Co., Ltd), unveiled the company’s non-combustible color steel for the first time.

Most fire casualties occur when victims inhale smoke or toxic gases – which is what POSCO C&C tried to address when they developed the new non-combustible steel. How did the company develop a new building material that hardly burns and hardly fumes?

(1) KS F ISO: Non-combustibility Test
POSCO C&C primarily focused on developing a product that meets the KS F ISO criteria, set by the Korea Conformity Laboratories (KCL).
The non-combustibility test measures the burning behavior of a material. Test material is placed into a furnace. The furnace heats the material at 750°C for 20 minutes. The maximum and equilibrium temperatures are measured, as well as the mass reduction of the material.

To meet the KCL standards, the difference between the maximum temperature and the equilibrium temperature should remain below 20°C — and the mass reduction should be 30% or less.

▲ Non-combustibility test conducted by POSCO C&C. The test materials are heated at 750°C for 20 minutes — then the maximum temperature, equilibrium temperature, and mass loss rate are measured. (Image source: POSCO C&C)

Normally, when a test material catches fire, the temperature rises quickly — by over 20℃. For conventional color steel plates, the temperature increase is around 80 ~ 100 ℃. As for POSCO C&C’s non-combustible color steel, the temperature difference between the maximum and the equilibrium levels is within 20°C.

When a material burns, a certain level of mass reduction is expected — the volume reduction signifies the amount of materials burnt. As for color steel, most weight of its weight comes from the steel portion. This means color steel retains most of its mass even in the event of a fire.

<Non-combustibility Test: Criteria>

(2) KS F 2271: Toxic-gas Test
The second criterion POSCO C&C strived to meet was the toxic gas test, KS F 2271. In this test, eight laboratory rats were put in a rotating wheel measuring how long they can rotate until they stopped — this time is defined as ‘action stop time.’

The running rats were exposed to the fumes produced by the POSCO C&C non-combustible color steel. KS F 2271 requires the action stop time to be longer than 9 minutes — which means the rats must continue to move at least for 9 minutes.

The KS F 2271 assesses the toxicity of gases generated by test materials predicting the required time for evacuation. The non-combustible color steel produced by POSCO C&C satisfied the 9-minute requirement set by the KS F 2271 thereby proving its suitability in securing evacuation time by minimizing the amount of toxic gases during a fire.

l POSCO C&C’s Non-combustible Color Steel vs Conventional Color Steel

<Non-combustible vs Conventional Color Steel>

As for the corrosion resistance and water tolerance, the POSCO C&C non-combustible color steel was on par with the Polyglycerol Sebacate (PGS), conventional building materials.

With the hardness level of H, non-combustible color steel was more solid than PGS, whose level was at H. Ultimately the result means that non-combustible color steel is more resistant to scratches.

As for the thickness level, the situation is slightly complicated. POSCO C&C representative Tae-Yol Park says, “If we solely focus on producing non-combustible steel, thin steel sheets are better. But what we’re trying to produce non-combustible color steel, without compensating the qualities the conventional color steel offered — in terms of color variations, durability, etc. in which cases it’s actually better to have thicker steel sheets.”

In this aspect, POSCO C&C was able to boost the thickness of its non-combustible color steel, while retaining the key qualities for the conventional color steel. The company’s R&D effort to boost the thickness even more is ongoing.

In addition to the non-combustibility test (KS F ISO) and the toxic-gas test (KS F 2271), POSCO C&C administered an internal test, a torch heating test. Both the conventional PGS and the new non-combustible color sheet were put through the testing.

When torched, PGS left a clear pattern, whereas non-combustible left relatively blurry patterns. According to Park’s explanation, clear patterns mean the material burnt more.

Park also noted that the non-combustible color steel produced far fewer fumes than the PGS. Albeit a simple comparative experiment, the low fume generation signifies that POSCO C&C’s new product is less likely to generate toxic fumes — which will help to secure more visibility and evacuation time in case of a fire emergency.

l POSCO’s Non-combustible Color Steel, What’s Next?

Color steel sheet is used as building exterior materials, so safety is the top priority. However, the aesthetic element is also crucial. Currently, non-combustible color steel plates are available in various tones of the following three colors: beige, grey and white.

▲ Non-flammable color steel is currently available in three colors: beige, grey, and white. The R&D endeavor continues to diversify the color tones (Image Source: POSCO C&C).

The colors are limited to the three tones because the current priority is to ensure the non-combustibility of the new product. POSCO C&C will continue the R&D endeavor to expand the color patterns into solid colors as well as metallic colors.

l POSCO C&C to Prioritize Safety and Sustainability

Non-combustible color steel has various usages. It can be used on walls, roofs, or even as solid structural material. Considering its non-flammable characteristics, however, it can best serve its intended purpose when used on the ceiling or as an interior material.

POSCO C&C’s lead researcher In-Kyu Kim addressed the challenges behind developing the non-combustible color steel sheet. Maintaining non-combustibility without compensating the qualities of the conventional color steel was the hardest, especially considering the two-month time constraint to obtain the official certification.
Despite repeated challenges and obstacles, POSCO C&C successfully developed an innovative product that will help protect buildings from fires.

Not all obstacles are gone — low-price, low-quality color steel from China makes it so easy for the industry stakeholders to opt for a quick fix over safety. The wider application of high-quality non-combustible steel can help save lives, ultimately enhancing overall safety across the country, Kim adds.

What’s next for POSCO C&C? The company will continue the endeavor to help build safer buildings. Going forward, POSCO C&C will also continue developing ground-breaking products focusing on environmental sustainability and safety.

▲PosART wall decoration at the ‘Youth Nuri’ housing project (Source: POSCO C&C)

The winter has finally loosened its grip, and the warmth of spring is peeking in the air. Flowers blossom at the lobby of ‘Youth Nuri,’ a share-housing project in Seoul Seodaemun district – in the form of, none other than PosART (aka POSCO Artistic Steel). The vibrant color palette symbolizes the youth residents’ passion and dreams sprouting and springing up here at Nuri.

When inkjet printing technology meets steel, it becomes PosART, the semi-permanent and high-resolution inkjet print that just became commercialized in Korea last year.

On March 7, POSCO C&C (POSCO Coated & Color Steel Co., Ltd), a color steel sheet manufacturer, broke ground for PosART Marble, an upgraded version of its PosART that can emulate the textures of marbles. Meet PosART Marble, a steel sheet in marble, at POSCO Newsroom:

l PosART Marble: Made Better, Cheaper, Safer

Formaldehyde and radon, both known to be human carcinogens, were recently discovered in synthetic and natural marble, respectively, creating a huge controversy in the market. Compared to the marbles, PosART Marble is safe and recyclable.

POSCO C&C’s Bo-Geon Kim who is in charge of expanding demands for the new material explains, “both steel and glass are toxic-free therefore eco-friendly. PosART Marble is just that, as it is created by putting together ultra-thin glass onto PosART. With PosART Marble, the surface strength is over 20 times higher with the resistance to chemicals also improved.”

▲POSCO C&C’s brand-new PosART Marble combines steel and glass. It’s stronger and more sustainable. (Source: POSCO C&C)

PosART Marble emulates the luxury of marble via vivid inkjet print, and 50% more cost-effective than natural marbles. The benefit doesn’t end there – the bigger the size, the cheaper the price. Hence the rave reviews from its clients.

While marble is susceptible to staining when moisty, in which case expert help needs to be called in to remove the smudge, the maintenance is extremely straightforward with PosART Marble. Moist wipes or glass cleaners are sufficient to keep it clean.

<Marble and PosART Marble: Comparison>

l PosART Is Steel Art

PosART does not need molding. Prints can be modified at will, which means customizing PosART as per each client’s demand is a mission not only possible but extremely viable. The fact that it allows full-color printing on steel sheet is how PosART earned its nickname, steel art.

What exactly is the production process for this steel art then? Printing colors on steel instead of on paper requires printer and ink customized exclusively for steel printing. First, the steel sheet must be pre-processed; then ink must be added onto the sheet; lastly, it undergoes the coating process.

Min-Ha Lee from the POSCO C&C noted, “In my experience as a designer, stainless steel plates really bring out dark colors like black and navy, or deep vivid colors like green and blue. The colors and the material complement each other.”

Just as Lee mentioned, a family photo from a scenic beach or mountains, when printed on stainless steel plates, created a subtle and flattering ambiance.

PosART’s merit truly shined when creating nameplates for the heroes of Korea’s independence movement. POSCO provided financial support to make these nameplates which used 0.9 mm color ink.

With steel art, a 0.1 mm in the ink thickness can create a huge difference. Lee remarked, “We experimented with various ink sizes from 0.2 mm to 2 mm. We felt them both with our eyes and hands. We wanted the nameplates to have just the right amount of three-dimensionality without looking too protruding. Achieving that fine balance was challenging, but in the end rewarding.”

▲Nameplate #1 for Korea’s freedom fighters (Source: Ministry of Patriots and Veterans Affairs)

PosART can be reborn – as a proud family heirloom for the descendants of freedom fighters or a steel photo album for those who want to preserve fond memories. The exquisite aesthetics it creates make it an excellent material for both exteriors and interiors.

Competition for market dominance remains fierce for color steel plates. How will PosART claim its presence and become a positive trigger for the market? The journey has begun, and the step that needs to be taken is only forward – one step at a time.