As a traditional company active in the circular knitting sector, Terrot is faced daily with new demands and expectations by its customers and their respective markets. With an export quota of around 95%, we play a globally active role with our range of innovative developments and market-oriented products.

State-of-the-art, economical Terrot circular knitting technology offers today's user a wide range of directions for development. In a period marked by the increasing relocation of production faculties to low-wage countries, one of our roles to offer support to our customers in the implementation of their projects and ideas.

Because of their versatile physical attributes and the new application scope they open up, spacer fabrics have recently become the focus of particular attention. Using new possibilities and improved machine technology, spacer fabrics have already become an established feature of many of the fabric collections presented by our international customer base. Some years ago already, Terrot began work on the development of spacer fabrics produced on mechanically and electronically controlled jacquard circular knitting machines. Through continuous improvement of both the technology and the produced fabric quality, we are now in a position to offer a variety of circular knitting machines capable of producing spacer fabrics to the very highest standard of quality for a wide range of applications. Within the framework of a research project in cooperation with ITV Denkendorf, Germany , we have also made a close study of the use of jacquard patterned spacer fabrics in the automotive sector. On the occasion of the ITMA in Birmingham 2003, the first gauge 32 gg electronically controlled jacquard machine for the production of spacer fabrics with wide wind-up frame was presented by Terrot to the trade public.


What are spacer fabrics?

Spacer structures are knitted fabric constructions comprising two separate fabric webs which are joined together by spacer threads of varying rigidity. The spacer threads are generally made of PES or PA monofilament yarns. The threads of the dial and cylinder stitches are made of textured PE filament yarns, depending on their intended field of application. The degree of space or height between the two fabric faces is determined in the circular knitting machine by the setting of the dial height relative to the machine cylinder. Spacer fabric heights preset in this way can vary between 1.5 and 5.5 mm. Spacer fabrics can be subdivided into jacquard patterned and plain knitted 8-lock structures. Electronic individual needle selection in the cylinder cam of the circular knitting machine permits almost unlimited pattern repeats coupled with maximum patterning variety. The thickness and cross-section of the monofilament yarns, together with the knitted construction selected, determine the force with which the two fabric webs are kept apart. The construction repeats can reach over several knitting systems. The majority of spacer fabrics are currently produced using 8-lock circular knitting machines. As it still offers the greatest scope for design versatility, electronic jacquard technology affords the best prospects for the implementation of spacer fabrics.

Which features distinguish spacer fabrics from conventional circular knit goods? Spacer structures offer more extensive conditions for varied application, as their stable 3D structure encompasses scope for distinctive design and possesses special physical attributes. Spacer fabrics

• are lightweight, soft, pleasant on the skin
• offer active breathing properties
• are pressure-elastic
• transport and absorb moisture
• have definable elasticity properties
• have thermo regulating properties
• are wash-resistant
• are ageing resistant and capable of sterilization

Market perspectives and possibilities

The manufacture of elaborate composite fabric constructions for the underwear and corsetry sector was previously only possible using cost-intensive individual work steps. The finishing steps involved for gluing and laminating processes are highly labour-intensive and in many cases also pose a burden on the environment. Another drawback of composite constructions used in the underwear sector is the ageing / discoloration of the used PU foam material. Spacer structures were manufactured in the past exclusively on collective needle motion knitting machines involving elaborate and time-consuming machine set-up processes. On circular knitting machines, spacer fabrics can be economically produced even in small batch sizes. The resetting times are correspondingly reduced on circular knitting machines compared to collective needle motion knitting machines, while circular knitting machines also take up only a fraction of the space. This allows rapid responses to fast-changing markets and fashion trends. Another benefit in favour of circular knitting technology is the bi-elasticity of the produced spacer fabrics. This is particularly essential where fabrics are used to produce underwear. Knitted spacer fabrics comply fully with this market demand, as they are required to demonstrate this characteristic for the subsequent moulding process. In addition, circular knitting machines with their electronic individual needle selection extend both the patterning possibilities and the fields of application for spacer structures.

Recyclable seat covers:
The requirement for 100% recyclable seat covers in cars provided the impetus for the development of jacquard-patterned spacer fabrics by the automotive engineering industry already some years ago. One of the problems faced is that of environmentally compatible disposal of sound-insulating composite and seat constructions in the automotive sector due to the still inadequate separation of material types. Spacer fabrics made of just one material type - 100% polyester fibres – can provide an economical alternative here. Seating comfort and seating climate are closely bound up with the structure of the vehicle seat and the degree of air circulation. As test results using circular knitted spacer fabrics show, the air circulation afforded by this type of fabric is many times higher than with the sandwich laminated materials used today.

Mattress Ticking:
Spacer fabrics also offer a viable alternative to address demands for textiles with bioclimatic and hygienic properties. Circular knitted spacer fabrics are already employed in a practical application as mattress covering materials. These are produced on electronically controlled Terrot jacquard machines with diameters of up to 42“. The fabric width corresponds here to the length of a mattress, so effectively preventing crease formation in the mattress cover. Further development work is focused on functional improvement coupled with good pressure-elastic properties and surface characteristics suitable for the application of skin sensor technology. Because of their typical construction with gauge ranges from 18-32 gg, spacer fabrics offer optimum conditions for preventing the build-up of moisture and heat close to the skin and for creating a skin-friendly microclimate.

Orthopaedics, decubitus prevention:
Spacer fabrics offer far superior characteristics to those of textile composites such as woven or non-wovens for medical applications such as orthopaedics, prevention of decubitus for the long-term bedridden, for surgical applications and convalescence, as well as for incontinence products.

Protective and sports clothing:
Other promising applications in prospect for spacer fabrics are opening up in the field of protective and sports clothing. Through the use of flame-retardant yarns and the construction of climatic zones in garments, spacer fabrics are ideally suited materials for the production of fire-fighting suits and overalls, as well as for the police and emergency services.


The manufacture of spacer fabrics on Terrot machines

On principle any of the Terrot double jersey machines is suitable for the production of spacer fabrics. However, ideally machines with electronic needle selection UCC572/ 548 and the 8-lock machines I3P154/ 354/ 572/ 284 are used. All machines require suitable preparation. Details of the necessary equipment depend on the fields of application and intended use of the produced fabrics. In the following, 2 typical application examples for spacer fabrics are outlined in closer detail:

• The underwear sector, using the example of
  Terrot type I3P284
• The car seat cover sector, using the example
  of the Terrot type UCC548

The underwear sector
The Terrot I3P series follows in the footsteps of a long tradition at Terrot. This machine offers users universal application scope coupled with optimum production output. Offering 84 effective knitting systems with a 30“ diameter, gauge 32 gg, the type I3P284 is particularly suited to the production of spacer fabrics. The machine features mechanical needle selection and is equipped with up to 4 needle tracks in the cylinder and 2 needle tracks in the dial. Use of the 3-way technique at every feeder offers the user whole new markets for a wide range of structures.

The monofilaments are fundamentally bound into the spacer fabric in the form of loops. For reasons of both appearance and also wearing properties, these threads must be covered by the microfilament yarn, i.e. they may be neither visibly nor tangibly perceptible on the worn face of the fabric.

Car seat covers
Renowned car seat manufacturers have been concerned for years with finding ways to improve seat comfort. Particular importance is attached in development work not only to enhanced seat comfort but also an improved sitting climate. Within the framework of a research project, the research institute ITV Denkendorf has joined forces with Terrot to investigate the possibilities offered by spacer fabrics for seat covering applications.

The electronic jacquard machine type UCC548, 30“, 20 gg was used for the development of the fabric. This machine type offers particularly universal application due to its extended knitting possibilities. Initially, the research engineers developed fabric surfaces and designs similar to the appearance of fabrics used today for the manufacture of car seat covers. Further development work was aimed at surfaces which may be considered totally new in both optic and haptic terms. Another objective of the investigation was to develop spacer fabrics capable of completely replacing foam lamination in the vehicle seat through the integration of PES monofilaments. The research team also aimed to use spacer fabrics to improve the physical characteristics and comfort of conventional seat covers.


Fields of application and possibilities for spacer fabrics