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Choosing the right vinyl

October 1st, 2010 / By: / Feature

Select laminated or coated products based on need, not bias.

Macs and PCs perform the same computing functions, yet you’ll find people align themselves with one or the other: “I’m a Mac.” “I’m a PC.” You may find the same sort of side-taking when you ask people about vinyl fabrics. Some champion laminated vinyl; others swear by coated vinyl.

Strike a monogamous relationship with your laptop if you must; but if you work in the industrial fabrics arena, you might want to play the field.

Alex Kouzmanoff, vice president of Aztec Tents in Torrance, Calif., boils it down this way: “If you look at the chemistry, both are PVC and both are applied to a polyester mesh or scrim.” Either you are sandwiching the base fabric between PVC films or you are pouring liquid PVC over it.

“Oftentimes, people in the tent rental industry are probably mischaracterizing when they talk about differences between coated and laminated,” he continues, “because they’re receiving a 16-ounce laminate, whereas coated fabric is generally around 23 to 24 ounces. So you are not comparing apples to apples.”

Both types of fabric have a wide range of performance, says Drew Nelson, awning and industrial products manager for Cleveland, Ohio-based TriVantage. “Laminates usually are used for lighter-weight applications, such as tent sidewalls. You find coated fabrics in heavier-weight ranges, such as for large clearspan tents.”

Glen Raven-owned TriVantage—a distributor of fabric for awnings, canopies, tents, marine use such as bimini tops, and transport/industrial covers—obtains laminated vinyl from a division of Glen Raven in the United States and coated vinyl from a division in France.

“Domestically, there are very few suppliers of coated fabric,” Kouzmanoff says. “Our primary supplier [of laminated vinyl] is within 15 miles of our production facility. I get 500 yards black on one side and pink on the other. I have that in three to four days. When I call [coated vinyl] suppliers in Europe, the minimum order is 3,000 meters, about 3,300 yards, and it would take 14 to 16 weeks to get that run and delivered.”

The locality aspect allows more customization. “You can work with vendors on small runs,” Kouzmanoff says.

“As I understand it, Europe uses more coated than laminated vinyl because they have more fully embraced coating technology for use in semipermanent, soft-wall structures like warehouses, exhibit halls and other permanent structures,” says Sherry Webb, government sales manager of BondCote Corp. in Pulaski, Va.

One of the few U.S. companies that manufacture both coated and laminated vinyl, BondCote originated in 1949 as a fabricator of urethane Army ponchos. According to Webb, the company in 1952 decided to purchase a coater to become vertically integrated, then in 1963 moved away from fabrication altogether. BondCote subsequently also became a laminator to supply markets looking for less-expensive products that did not require a long life. “Coated vinyl is typically a longer-term product. Of course, lamination has greatly improved in technology,” Webb says.

But even as laminated vinyl moves closer to coated vinyl in longevity, it remains less expensive. Webb explains that’s in large part because extruded/calendared films, substrate configurations and adhesives allow the fabric to be processed in one pass, whereas wet compounds are applied over the substrate in multiple passes.

“There is a misconception that coated fabrics are better than laminated fabrics or that they last longer,” says Jeff Sparks, business manager for tent structure fabrics at Herculite Inc. of Emigsville, Pa. He notes that one reason lamination (which his company has been doing for more than 60 years) costs less than coating is because it requires a smaller capital investment by manufacturers.

Weight and see

For some applications, a lighter weight, inexpensive alternative is perfectly appropriate, according to Kouzmanoff.

Troy Burns, product manager for the industrial textile fabrics division of ABC Industries Inc., a vinyl laminator in Winona Lake, Ind., says that for high-tension structures, a large majority of the market currently uses 22-ounce per yard or heavier coated fabric, but laminated fabrics in this weight range have also been proven to perform well. “In contrast, a tent manufacturer making smaller party or event tents does not typically want the additional cost of a heavyweight coated fabric,” he says.

Keeping a structure as light as possible becomes a selling point when a product will be shipped, put up and taken down regularly. In terms of strength-to-weight ratio, laminated vinyl claims an advantage over coated vinyl, according to Sparks. “Tent renters want to keep the weight down, but they want it to be strong. The end product is large, so every ounce adds up.”

Because coated vinyl tends to be heavier, it contains more PVC, and thus there’s more PVC to “displace” before it develops a pinhole. And though the PVC is thicker in the valleys of the underlying mesh, the overall thickness of the fabric is the same. With laminated vinyl, the PVC film conforms to the hills and valleys of the mesh so the finished fabric presents a rougher surface that is more susceptible to abrasion and resulting pinholes.

“There’s no question that a coated fabric is a lot easier to clean because it’s smoother on both sides, which transmits into better resistance to abrasion and pinholes,” Kouzmanoff says.

But Burns says the appearance of pinholes largely depends on the quality of the film used in lamination. “We have strict specifications that all films need to meet regarding thickness, color, stiffness, ultraviolet resistance, etc. There are typically 10 or more different specifications that all films must meet before we will use them.” Fabric durability, he notes, relies on a combination of the strength of the polyester reinforcement and the thickness of the PVC. “Thus, coated and laminated vinyl will react to their environment in much the same way,” he says. “We attempt to debunk the myth that laminated fabrics are somehow inferior to coated fabrics.”

ABC does, however, caution customers against using laminated vinyl for products that are subject to wind whip, such as truck tarps. “In these cases, a laminated fabric may experience PVC separation quicker than a coated fabric,” Burns says. “Our main objective is that the customer receives the correct fabric for their application.”

According to Sparks, Herculite has adjusted its formulations to lessen the occurrence of pinholes and has put antimicrobials into the adhesive, which doubles the protection against mildew, since it bonds to both sides of the PVC. The company currently is also working on adhesion promoters.

“When you experience a mold or mildew issue, typically you have a problem with exposed polyester,” says Burns, adding that ABC tests incoming polyester scrim for anti-wicking properties and adds mildew inhibitors to many of its fabric products.

While mildew resistance and cleanability can be formulated into either process, appearance can be an issue, according to Webb. Scrims for laminated vinyl tend to be more open so the layers will adhere into one piece of fabric, whereas substrates for coated vinyl tend to be more closed to allow the chemical compound to flow evenly over the scrim.

Topping it off

Topcoats can be added to provide enhancements, such as UV protection, cleanability and durability. Coatings also can provide a glossy finish that may improve cleanability.

“Some people have a preference for weldable PVDF [polyvinylidene fluoride] tents. It offers more dirt and wear resistance,” says Steve Fredrickson, architectural market manager for Ferrari Textiles. “If they want to digitally print their tent top, which is becoming popular, they need a topcoat that is ink receptive.”

Ferrari, which is headquartered just outside Lyon, France, offers four types of topcoats. The standard coating—an acrylic varnish—enhances dirt resistance and longevity and can be printed on with some types of inks. It can be used in Ferrari’s Alu product (the company’s most expensive finish), which features an aluminum top varnish with three interior color options (white, gray, black). “Look at cars and the ones that show the least dirt are silver,” Fredrickson says. “That’s been a popular, high-tech look. It is an acrylic topcoat, so it takes graphics.”

Ferrari also offers PVDF coatings that provide high levels of dirt resistance: one that is weldable, allowing a structure to be put up and taken down as needed, and one that is nonweldable that hardens over time, making it best for permanent structures.

While some technological advances improve both laminated and coated vinyl (such as dimensional stability gained in the switch from nylon to polyester as a substrate), other developments, such as improved adhesion systems, have zeroed in on the lamination process. And more progress is on the way, including more eco-friendly plasticizers and antimicrobial protection, says Webb, who also forecasts sunny skies for the tent market.

“A lot of work is going on to improve insulation by incorporating composite liners and higher reflective pigments to reduce solar absorption,” he says.

Janice Kleinschmidt is a freelance writer based in Palm Springs, Calif.

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