Recently, Arrow launched a luxury shirt collection, Superluxe – The Stitchless Shirt. While the traditional method is to join fabric panels via sewing to make a shirt, adhesive material to join fabric components has been used in making this shirt. The technology is said to eliminate the problem of puckering on the seams of shoulders, side seams and armhole of shirts, something that the Indian man is becoming increasingly conscious about. StitchWorld invited Dr. Prabir Jana to review the product and critically comment about the technology.
When I first commented in StitchWorld in 2007 that the future trend of fabric joining will be welding and that the use of needle and thread will become lesser and lesser, least I expected that it will be asked to conduct a review/autopsy of a stitchless shirt so soon. I had always visualised that the first marketable stitchless shirt would eliminate just the top stitches and the joining would still be done by sewing, but it was a pleasant surprise to see that the shirt is actually 100% stitchless, top stitches are completely eliminated to give a richer formal look and all joining are by bonding technology. The common visible areas where generally topstitches are done in traditional sewn shirt like collar, cuff, yoke and shoulder, are characteristically flat and surely gives a neat look of a dress shirt. The patch pocket at chest is very impressively attached with 100% matched stripe, and due to absence of top stitch it gives a look of blazer pockets.
There are primarily two ways by which two or more plies can be joined together without using a needle and thread. First is by fusing two plies together at very high temperature where fibre content of the fabric is thermoplastic; fusing is done either by ultrasound welding or by hot wedge/air welding. This technique does not use any adhesive in-between two plies and is commonly used in making disposable nonwoven bags now commonly used as replacement of plastic carrybags. Second technique is the use of adhesive or glue to paste two plies together. While the first technique requires 50% or more of fibre content of the fabric to be thermoplastic, the second technique can join fabric of any fibre content, even 100% cotton. The stitchless shirt by Arrow is 100% cotton fabric, thus glue bonding technology is used to join the parts together.
The traditional bonding technology offered by MACPI, uses a three-step process. In the first step, adhesive tape is applied at the edge of the fabric with backing paper on top. The tape is applied with a bonding machine which looks quite similar to a sewing machine where single layer of fabric is passed through two rollers and tape is attached from a tape dispenser. In the second step, the backing paper is peeled off which is generally done manually by hand just before the third step. Finally, in the third step, the second ply of fabric is placed on the adhesive tape and a regulated temperature and pressure is applied to attach the second ply.
The machine used for third step may be of three types: First, a simple continuous fusing machine can be used where the seam lines are straight and flat; second, flat bed fusing machine with 3D shaped bucks can be used where seam lines are curved; and lastly, sewing machine like bonding machines with continuously heated top and bottom belts used for single or tubular assembling (like sleeve).
Adhesive applying machines are sewing machine lookalikes with table, machine head with roller, different bed types for easy manoeuvring of the fabric, side fabric trimming device equipped with hot chute or front blower and upturn felling attachment. The sewing machine lookalike bonding machines are used for assembling two plies where adhesive tape is already applied on one of the plies. These machines do not have stitch formation mechanism or feed dog but still have a needle for visual guidance for the operator to help in long panel joining. The needle is generally in ‘up’ position while the machine is running, but comes ‘down’ when operator stops the machine for repositioning or pivoting the panels.
There is another option available for bonding where adhesive laying, and temperature and pressure application for bonding happens in one go. The liquid adhesive is dispensed by a specially designed nozzle between two plies of fabric just before the pressure roller. This is comparatively newer and faster technology but requires bonded panels to dry after it comes out of bonding machine. The Brother BM 1000 offers this technology.
Construction of the Stitchless Shirt
Primarily three different seam types are used in the construction of the complete shirt. Collar, cuff runstitch are done by first applying the adhesives followed by seam bonding, using continuous belt fusing machine and after turning inside out and pressing to finish.
Sewing of yoke, armhole, sleeve placket and front placket, requires adhesive tape to be attached first to one ply of fabric component using adhesive applying machine and then bonding is done in carousel type machine with pre-defined shaped bucks. Second component is placed over the adhesive tape (after manually peeling the backing paper) and temperature and pressure is applied to bond two plies together followed by cooling station to set the joint.
Sewing of side seams are first done by adhesive applying machine followed by feed-off-the-arm bonding machine with continuous heated top and bottom belts. Sewing of bottom hems are by first applying adhesive followed by automatic edge fold-over machine.
The first look at the folded shirt gives a neat and clean impression of the collar, cuff, front placket and pocket area. While no topstitch is visible, the seam areas are free of either any puckering or untoward impression of adhesive bonding. The brand logo at the inside yoke is perfectly aligned and probably transfer printed. Although adhesive impression is visible on back side of pocket, the pocket attaching is cleverly done to avoid any impression of adhesive on face.
The armhole appearance from top is flat and puckerfree; however, the impression of glue is visible at places and particularly awkward for stripe or plaid due to criss-crossing of stripes. The backside of armhole seam is particularly unacceptable due to clearly visible raw edges whereas the manufacturer could have better finished the inside of seam. The process followed is that first the armhole edge is felled edge inside and adhesive tape is applied on the felled edge, the adhesive tape width covers double the felled width. Currently the sleeve is simply placed over the tape, thereby the sleeve raw edge is visible at back. The better method could have been to first ‘downward fell’ the sleeve edge and then place on top of adhesive tape to give a flat seam appearance. Side seam assembly which also has similar problem of visible raw edges at the back side of side seam could also have been visibly improved with technique.
Technology for the Arrow Stitchless Shirt
Seam strength of stitchless shirt is also claimed to be higher than an ordinary sewn shirt because during needle penetration some damage happens to the fabric seam area.
The most prominent product advantage claimed is improved DP (Durable Press) rating of 3.5 to 4.5 for crease resistance, which is just 3.0 in case of a normal sewn shirt.
Arrow claims that the shirt is being manufactured in China using patented technology and the manufacturer is mentioned as Luthai Textiles. This listed Chinese company is the owner of over 600 patented innovations in the textile industry globally. The relevant patent search defined the invention as “where the sutureless (means stitchless) shirt fabric itself does not contain the binder fibre component, and the main construction process is divided into the cutting process, the wireless (means threadless) sewing step and the ironing step.”
The fabric is cut into components, in whole or in part conjoined crop; adhesive applied in wireless sewing technique. The ironing process uses the skeleton bonding technology with shape and/or three-dimensional pressing machine at high temperature followed by cooling to room temperature to obtain the final shirt. While both Luthai and patent literature are tightlipped about the commercial machinery being used for making the shirt, MACPI claims to supply the entire technology and machinery to Luthai Textiles, China. Other similar technology available is NoSo heat welding machine from Framis Italia.
The width of the adhesive film varies from 0.2 to 4 cm based on requirements in different seams in the shirt. The front placket uses widest width while bottom hem uses the least width. Welding parameters varies from 100-190°C, pressure of 0.5 to 8.0 kg/cm2, and time from 10 seconds to 40 seconds and primarily depends on chemical composition of adhesive, i.e. thermoplastic polyurethane (TPU), polyamide (PA) or polyester (PES).
Patent document of the stitchless shirt proposes two alternative pattern cutting modes for the stitchless shirt. The first, where sleeves front and back are one piece (Figure 1); and second where front and back are one piece (Figure 2). This is definitely an approach towards minimising the joining operations, questioning the fundamental framework of pattern making to fit a human body. Till three dimensional shaped fabric become realities, this option remains a dream.
The most prominent product advantage claimed is improved DP (Durable Press) rating for crease resistance. DP rating of normal sewn shirt after 20 wash cycle is 3.0, while the stitchless shirt after 20 washes shows a DP rating (flatness level) of 3.5 to 4.5. The collar is likely to retain shape better than ordinary ones due to use of special plasticity shaped memory cord interlining.
Seam strength of stitchless shirt is also claimed to be higher than ordinary sewn shirt because during needle penetration some damage happens to the fabric seam area, therefore poor fracture resistance in traditional seam. However, no test result was cited to substantiate the claims.
Traditional stitch formation using needle and thread requires fabric to be fed intermittently (and not continuously). However, continuous roller feeding can happen in case of adhesive welding; thus a potential advantage of the stitchless shirt may be higher linear speed of sewing subject to operator able to feed the fabric plies.
I am sure the future of stitchless garment is going to scale many heights while challenges are nonetheless many. Although 100 washing cycle is being claimed by the manufacturer, the raw edges inside raises serious doubt over the actual washing cycle the shirt can withstand. The patent application also claims cost saving due to uncomplicated processes and saving in consumables like needle and thread.
However, from the working processes it appears the assembling will take double the time (due to two separate processes of applying adhesive and applying temperature and pressure even ignoring backing paper removal time), with additional cost of adhesive and cost of extra energy consumption. If the single step bonding machines (like Brother BM 1000) can also incorporate in-built continuous belt drying, probably production will become faster. Currently, there is no way to give top stitch appearance and is a serious bottleneck aesthetically; however, I am sure in near future it will be possible to create different decorative top stitch impression similar to ultrasonic bonding.
Two questions still remain unanswered: First, what is actually patented… The process or technology? While the technology is commercially available, it seems the manufacturing process is patented; does it mean any other manufacturers need to pay royalty to put up similar stitchless manufacturing plant? The inventor’s name from patent literature apparently indicates they are employee of Luthai, does this indicate Luthai and MACPI jointly developed the technology? Second, why Luthai selected three step bonding technology while more advanced single step technology is available in the market? Does this indicate that when Luthai invested in this technology, single step bonding was not available in the market?
Technology will definitely keep evolving in this segment and some exciting future is beckoning us, till then enjoy wearing the stitchless shirt and write back to us after 100 washes!