Printing goes all soft for interiors and garments: a tutorial in textiles

By Jon Severs Thursday 22 November 2012

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Print may traditionally be a macho industry, but to survive in the current climate takes diversity - which may explain the move into printed frocks and cushions.

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It’s admittedly odd to hear otherwise-blokeish printers discussing the ‘hang’ of polyester or the ‘feel’ of a digitally printed dress; this industry has long been regarded as a little macho. But the lexicon of textiles is set to become the norm for printers of multiple backgrounds if we’re to believe those touting textiles print as the next big thing. Though quite what ‘textiles’ means is difficult to pinpoint.

"The problem is the word ‘textile’ means different things to different people," explains Barney Cox, senior consultant at Infotrends, which is currently working on a project looking at the transition from screen print to digital for textiles, called Transforming Textiles (to be published at the end of the year).

Indeed, while one textile print business could be producing flags and soft signage, another could be printing fabric to be made into clothes for the high street – or selling its own printed T-shirts – while yet another could be printing cushions for the interiors market. It is a very diverse market. And also very complicated.

"While the core technologies used, be they printheads, inks, software or substrates, may be similar, the requirements of the different markets are very diverse," says Cox. "Don’t think that having the right machine means you will be printing billboards at breakfast time, dresses at dinner time and ties before tea."

To ease some of the complications and to try and give printers of all backgrounds an insight to the potential textiles bonanza, this issue of PrintWeek is the Textiles Special Issue. The Me and My... (p14) and Star Product (p17) features aim to give you examples of the type of businesses and kit in the sector, while the Business feature looks at one of the most accessible areas of the market: T-shirts.

Forming the basis of all these features, though, is the below. PrintWeek’s Starter’s Guide to Textiles Technology, formed with help from some of the most experienced people in the textiles trade and split into the three key textile markets.

Soft signage

Applications Exhibition graphics, banners, signs, flags

Materials Polyester is the main material used for soft signage, predominantly because of its versatility. "It is such a flexible material, quite often it will be backlit. It can have a brushed finish and it can be a mesh," says Duncan Jefferies, marketing manager at UK Mimaki distributor Hybrid Services. He adds that while cotton and silk can be printed upon, they are not really suitable for the soft signage market, mainly due to cost and practicality.

Print technology Dye-sublimation printing – also known to some textile aficionados in the garment and interiors worlds as disperse printing – is the best way of printing onto polyester for most soft signage. "Using specific inks solely suited to polyester through a dye-sublimation process produces the best results," says Jefferies.

Banners For All owner Ralph Ballhatchet agrees. "Most other forms of printing you are just laying something on the surface and the result is not as good," he says. "When you absorb it into the weave of the fabric as happens with dye-sublimation inks, you get a superior result to any other printing onto polyester."

There are two ways of dye-sublimation/disperse printing onto the polyester: direct onto the material or print onto paper and transfer.

Printing direct requires polyester that has been prepared for digital printing with a coating. It then has to be fixed. The fixing is achieved through heat, generally via a rotary calendar press at 200°C. "It needs to be a good quality heat press that uses pressure as well, as that forces the ink into the material and it means you get very good durability," says Jefferies.

Printing to paper and then transferring can be used for uncoated polyester and polyester containing Lycra. It can also be used to print onto materials that stretch (which makes them difficult to print onto).

"We have been direct to cloth since 1999 as we could not see the point of the transfer method in our market," says Ballhatchet. "But people still use the transfer method in the higher end of the market, where you need incredibly fine and sharp detail. It can achieve that by printing to paper first the paper holds the ink at a higher resolution; it transfers at that high resolution. Printed direct you will always get a bit of spread."

You can also print with UV, latex and solvent for polyester, but these can produce less effective results than dye-sublimation. "Rub resistance, life-span and weather resistance are all better when using dye sublimation than UV, latex or solvent printing," claims Jefferies. "Also, using dye-sublimation means you do not change the handle or hand [this is the term textile aficionados use to describe how the fabric feels and falls, or drapes, and is vitally important in many applications] of the textile, where as the UV and latex will. Also, with solvent, you will not get the penetration into the fabric that you get with dye-sublimation."

Treatments To print direct to garment you need to have coated polyester that enables the polyester to hold the ink better. Coated material can be bought from a wide array of suppliers.

Additional kit As mentioned earlier, you will need a heat press, but you then have the task of displaying the printed textile. If you are going to suspend it you may need capability for putting it into frames, creating hems for silicon strips known as kaydars, or to create eyelets, so you need some sewing and cutting capability.

Interiors

Applications Cushions, curtains, blinds, wall hangings, canvases, bean bags and chair covers, with photo personalisation a growing trend.

Materials The most popular materials for interior products are cotton, linen, and cotton-linen and cotton-viscose blends. Polyester is also used for around 10% of interior textiles products. Silk and nylon are used for some.

Jefferies feels, however, that polyester has an unfairly bad reputation in the interior furnishing.

"Polyester has a challenge in that a lot of people think it’s a horrible crinkly unpleasant fabric – but it’s actually quite versatile," he says. "You can have all different sorts of finishes – canvas, voile, mesh, mimicking silk, cotton finishes; all sorts of finishes from the same base polyester fabric. It’s an incredibly technical fabric. A polyester cushion could feel like a very nice, heavyweight cotton fabric."

And polyester’s inherent fire-retardant properties can be very handy, says Ron Smart, managing director of RA Smart: "You can make cottons and linens fire retardant, but that needs to happen after you’ve printed, steamed and washed the fabric. Whereas a lot of polyester is made fire retardant at the point it’s spun."

Print technology As in all types of fabric printing, the ink technology used for interior products will depend on the fabric being printed on. The most commonly used fabrics – cottons, linens, viscose and blends of these mean using reactive dye inks, designed for printing on these fabrics. Meanwhile, dispersed/sublimation dyes are used for polyester printing, and acid dyes or pigments for silk and nylon.

Pigment printing is generally considered a more challenging process than others, explains Jefferies: "One of the challenges is that it typically has a smaller colour gamut, so that tends to be the domain of companies producing their own designs and printing them."

But the advantage of these inks is that they are better-suited to products such as curtains and hangings, where the material needs a certain kind of handle. Smart explains: "With some silks, like taffeta, you might want to retain the handle and the drape. If you go with acid dyes, the steaming and washing needed after this means you lose this. With pigment inks, you only have to bake the fix and that retains the handle."

What kind of printing machine is used to apply these inks will depend, as in the world of printing on paper and board, largely on run lengths. Shorter runs will be performed by an inkjet printer, while longer runs, and those requiring a special finish (such as a flock or devore finish, or white or metallic inks) are screen printed.

As elsewhere, though, digital is playing a larger and larger role in interior textiles printing. "With screen printing, you can’t do varied repeats readily because your screens have to made to a particular size," explains Smart. "Also, digital comes into its own for creating pattern books for soft furnishing fabric designers. You want to show the design without bits being cut off. If you’re trying to do that with screen printing, You’d have to have new screens made up. Similarly, digital is used for printing where you want the design to sit in an exact position [also known as placement printing], for cushion printing for example, so you print the shape of the cushion panel digitally."

Some would add that digital machines which aren’t dedicated textile printers are proving increasingly suitable for interior products. That is, some have started to use their wide-format latex digital printers not only for soft signage but consumer products too. "I expect that customers will be very surprised at the variety of different applications the latex printers can do," says Phil Oakley, Designjet country manager at HP. "We have seen applications where people have done interior design products on the Designjet."

But the range of products that can be run on a latex machine is at the moment limited, say some. "As a wall hanging or something that people might just rub against, like a drape in a dressing room curtain for instance, latex printing is fine," says Service Graphics technical director Peter Onyskiw. "But for products someone will take a brush to or put in the washing machine, you need to use a dedicated textile printing process."

Treatments Where a fabric is being screen printed, a coating to aid fixation is mixed with the inks and applied during printing. But coatings for fabrics being printed digitally must be applied as pre-treatments, as the nozzles on inkjet heads are too fine to allow these products to pass through. So here a coating is applied using a bath, followed by a squeeze through a pad mangle to ensure even application. The fabric is then weft-straightened and dried at the correct width through a stenter stretching and straightening machine.

The time at which coating is applied will depend on the fabric and ink with reactive and acid dyes requiring different
preparations.

While polyester doesn’t require a fixation pre-treatment, as disperse dyes will fix on this fabric without it, a preparation can be added to aid sharpness of print and penetration of colour. Similarly, pigment dyes don’t require a pre-treatment, but one can be added to improve colour yield. It may be necessary with pigment dyes to apply a post-treatment to improve wash and rub fastness, depending on end use.

Additional kit What ‘fabric finishing’ kit is needed will depend on what process is being used and so the fabric being processed. For locking in pigment inks, a baking machine capable of reaching temperatures of 140°C will be needed. With acid or reactive dyes, steam, pressure or just heat will need to be applied to fix the dyes. Which type of fixing is used will depend here, says Smart, on the colours used. "You will get better results with some colours one route than you will with another," he explains. 

Garments

Applications T-shirts, leisure wear, high-street fashion, high-end fashion, sports wear

Materials Include cotton, polyester, cotton-polyester blend, Lycra, viscose, silk, leather, denim, linen, nylon and wool

Print technology The garment sector is so wide that the technology really does depend on the application you are printing and what you are printing it on.

Direct-to-garment printing, either via screen or digital printers, is only really suitable for T-shirts as printed direct to high-street fashion such as dresses is incredibly difficult. Printing a design on the front and back of a T-shirt , however, is relatively easy. For T-shirts, a rough figure for the break-even between inkjet digital printing and screen printing direct to garment is 100 T-shirts. For darker garments, this will be lower, as for these the T-shirt has to have a white layer printed first, before the colour is printed.

For most other garments, you have the same mix of digital or screen technology in the main, but here you print continuously onto fabric reel, that will be made into
garments.

"Printing screen, you are more limited in terms of the colours than with digital, but it is cheaper to print this way for longer runs," explains Magic Textiles owner Paul Seymore. "Digital’s also still too slow, in my opinion, and the inks are very expensive."

However, Smart argues that screen printing is fast becoming redundant – as is dye-sublimation, another option for printing for garments.

"If you look at print speeds between screen and digital," he says, "the screen is uptime of 20%, downtime of 80%. So while they might run at 10 times the speed of digital, they are only running 20% of the time," he says. "In digital, it is the reverse; the presses are running 80% of the time. Similarly, with dye-sublimation, there are too many processes and so there is too much cost. High-end fashion has pretty much all gone digital now. That said, only on screen can you do things like devore and metallics. When those problems are resolved, screen will disappear pretty much altogether."

In terms of inks, Seymore says that pigment inks can pretty much print onto anything, but – as mentioned earlier – there are some issues with how they hang. Smarts, though, adds:"If you are printing on silk, it’s generally with acid dyes, on cotton you use reactive dyes. Digital is equal on quality to screen for both of those."

Treatments If you are screen printing, the fabric has to be pure, so no oils or softener which interfere in the process (also known as ready-for-print). After printing, it will need baking or steaming, washing and
fixing.

When you are doing a digital print, you need a pre-treatment on the fabric. You need to post-process it to fix the ink. Large- scale digital printers prepare their own treatments and buy totally untreated fabrics. They then automatically wash the fabrics to ensure absolute purity, as some chemicals that don’t affect screen printing – also present in ready-to-print fabrics – will cause issues with inkjet. Alternatively, smaller printers can buy fabrics treated for digital print. Admittedly, the range is more limited and the price is higher.

Additional kit If you choose to prepare for print yourself, you need coating, washing, stenting and straightening kit. You will also need post-print processing. This entails steaming, washing and stenting and straightening, unless you choose to outsource to an established printer. Beware, however, these machines are rather more expensive than the printers themselves. A textile printer is unlikely to offer any additional finishing, because the cutting and sewing is generally carried out by other companies. 

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