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Fantastic finishes keep fabrics looking fresh

May 1st, 2007 / By: / Category: Feature, Graphics

A finishing touch keeps fabrics at their best.

Colorful awnings invite customers to take a moment and stop into a new retail store. Large banners hanging on an exterior wall announce the grand opening of a local theater’s new play. Sidewalk cafés protect their patrons with large logo-festooned umbrellas. Walk through a retail district on a summer day and there is no question printed fabrics play an important role in day-to-day American commerce.

The colors are bold and beautiful on the day the elements are installed but Mother Nature’s whims can play havoc on banner and awning materials as time passes. High winds can fray the edges of a banner, harsh UV rays can fade colors, and exposure to moisture can result in mildew stains.

Fabrics used in interior applications face their own threats. Constant handling, dust, and fingerprints from curious consumers can degrade the fabric’s surface. Fortunately, print shops have access to fabrics treated with specialty coatings and laminates that are waterproof, flame resistant, and durable enough to look fresh months after installation.

Fabric Graphics has invited coating and laminating experts to review the fundamentals of finishes.

Juan Hernandez, sales manager, Dickson Coatings USA

Let’s say you are putting a banner outdoors where it will be exposed to rain, humidity, and the wind. The main reason to coat a fabric is to make sure it will be durable and last longer.

When an outdoor banner is exposed to extreme temperatures some of the materials used can start changing colors. Shifts in the yellow or green may alter the intended appearance of the printed banner. Extreme cold may also affect the colors, so UV protection is very important.

Most of the fabrics available for digital printing are either coated or laminated. A lot of people don’t understand the difference between the two. With a laminated product you have fabric in the middle and two plastic films, one on the top, the other on the bottom. With the help of heat, the fabric is glued to the film.

When the product is coated the fabric is immersed in a liquid so you don’t have any gaps between the coating and the fabric. After being submerged, coated fabrics are dried, rolled out, and prepared for storage and shipping. The thickness of coating is dependent on the application. Front lit, backlit, and double-sided banners will use different coating thicknesses.

Application first

Print shops need to first find out how the customer intends to use the fabric. There are a lot of coated fabrics designed for buntings, tents, and truck covers that are coated vinyl but do not necessarily have the chemicals in the coating that allow you to print on them. If not, you can’t print on it; the ink won’t take.

The best way to serve your customers is to test different fabrics to see what works best for their interests. Outdoor applications need durable products with UV protection. Inside, where a customer may be looking at the material closely, you want something elegant and nice. Since it will be indoors it will not be exposed to the elements, so the UV resistance isn’t as important.

The best advice I can offer is to buy coated fabrics designed for digital printing.

Richard Yale, vice president, sales and marketing, MarChem Coated Fabrics

Coated fabrics such as solution-dyed polyesters and acrylic-coated polyesters serve awning, marine, banner, flag, camping, outdoor recreation, safety, and industrial applications.

Most coatings contain chemicals that add UV protection, mildew resistance, water repellency, and flame-retardant properties. The coatings also enhance the base material’s strength—both tear resistance and dimensional stability.

Fundamentally, we are taking a basic fabric and applying these characteristics through the coating process.

Misconceptions

I think that print shops often assume that highly water repellant-coated fabrics cannot be successfully printed on or that you are restricted somewhat in the processes that will work or the ways you need to do it. With certain procedures and processes you can print successfully on coated fabrics that are highly water repellant.

Coatings can make printing more difficult. They do narrow the types of printing that might be successful, but coated fabrics are still printable.

We know coated fabrics can be successfully printed with large format digital printers using UV or solvent inks. The standard solvent or UV inks do very well. During the printing process these fabrics are stabilized by the coatings sothey don’t encounter the fraying or shrinking problems sometimes encountered with uncoated products.

Product improvements

We’re always testing different chemical processes for the coatings because we don’t want to put a feature in a product that negates another one. We want to try to offer all the necessary characteristics a customer is looking for in a product.

It’s about matching features to intended use. If it’s something that needs to withstand very high winds without stretching or fraying like an outdoor awning, print shops need to look for fabric coatings that address those conditions.

There are changes all the time. We always look at different chemicals that are available to us to improve the product’s overall performance. In the last several years we’ve made improvements in our formulations to give a drier, less tacky finish. Other changes have improved UV resistance. Specific chemical ingredients that make up the coating have been changed and improved to ultimately produce a better product.

Flames don’t flicker on fabric

The frightening thought of a fire in a public place is far from the minds of most people. Fire marshals nurture that sense of safety and security with their diligent efforts to identify, manage, and control potential problems. The majority of fabrics have flame-retardant properties, but print shop owners must be aware of current laws, regulations, and their customers’ intended use to do their part to keep the public safe.

Tom Andrews, president, Turning Star Flame Proofing Inc.

Flame-proofing is primarily used in public assembly areas where code restrictions require all decorative items to be flame retardant.

Throughout the industry more and more fabrics are inherently flame retardant, so there is less call for fabrics to be flame-proofed after printing. Still, there are also more events, more spectacles, and more shows being put on in malls and public spaces that require flame-retardant fabrics. Design trends also influence flame-proofing needs—for a while, soft flowing fabrics were popular, then the trend changed to sharp, clean edges with wood or steel.

Many of the calls we receive from print shops begin, “I have to get something flame-proofed. What does that mean? What do I have to do?” It’s

Many of the calls we receive from print shops begin, “I have to get something flame-proofed. What does that mean? What do I have to do?” It’s complete education from the ground up. We inform people about what flame-proofing is, how it works, what they have to do, how long it will last, what it will do with their fabric, what it won’t do. If there are particular things they are doing, we try to take that all into account.

People need to be careful about putting flammable ink over a fabric that has already received a flame retardant. At that point they are voiding the nonflammable quality they have created. It’s better to flame-proof the fabric after it’s been printed so that the flame retardant has an opportunity to soak into the ink as well.

Since the flame-proofing process is water based and water soluble, other coatings can also affect flame-retardant properties. If a fabric has been treated with a stain guard that prohibits liquids from being absorbed, the guard will make it impossible to print. The recommendation is print first, flame-proof second.

Small shops with low production runs will benefit from first creating the item and then applying the flame retardant. Larger print shops that work through bolts of fabrics can get the fabric flame-proofed first.

In most instances, print shops send their materials to us for coating, but flame-proofing can also be applied at their shop or on location. Normally sprayed on, the retardants can also be dipped or painted on with a roller. It’s vital to start with clean and dry materials. Depending on the type and thickness of the material and humidity, it can take a couple of hours to a day to completely dry.

For most shops flame-proofing may only come up very periodically so it’s very important to understand the appropriate laws. Fire codes have been on the books for a long time but they are just starting to be vigorously enforced on the local level. Certifications differ by municipality, so so check locally.

The shop owner will need proof of proper application for the fire department. The proof might entail doing a burn test with a small piece of the fabric cut from the project. It’s always good to do a test for yourself. It may need a second application or to be applied a little heavier.

Lou Dzierzak is the editor of Fabric Graphics.

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