Stahl has invested in state-of-the-art equipment for polymer research, leather chemicals technology, as well as coatings solutions for the apparel & home furnishing industry. 

The applications and testing facilities on display enable Stahl to develop solutions that meet even the most critical and rigid demands of performance, sustainability and style. Sustainability is a driving force behind Stahl’s product development strategy.

During our visit, we were able to see the machines available in the new Centre of Excellence (CoE) in Spain that process wet end and finishing (leather) and performance coatings (non leather). We were also able to see some of the tests that are performed.

      

Machines at the CoE Leather Dyes (Wet-End)

All the machinery available in this lab is designed to support the main production processes as described below:

Quality control of Dyes; some machines are used for the dye analytics itself like the Spectrophotometer UV-VIS (by Transmission), Lorentz test (dust value).

Others, like the small drums (Mathis) are used to test the dyes by applying them on different types of leather. Dyed leather is evaluated later by using other testing machines like: Datacolor (shade evaluation by reflectance in UV-VIS spectra), or machines which allow the measurement of the dye fastness: Xenotest (light fastness) or the fastness to washing, perspiration, light fastness, migration, according to standard methods.

Dye promotion / customer support: For this task there are a few specialist machines available. In one example small drums (Mathis type) are used to make trials at lab scale: for example color-matching as per bespoke customer requests. Another type of drums DOSE (similar to the ones available in tanneries but smaller) can be used to make application trials on bigger pieces of leather (for example, a few sheepskins or a full hide). In these drums, application recipes (using Stahl dyes and chemicals) are developed simulating the wet-end processes carried out in the tanneries. Once the leather pieces are dyed, mechanical processes can be undertaken as well in the lab by using specialized machines like: setting out machine, or buffing machine, ironing and shearing machine to produce wool-on articles.

Leather Finishing 

Many of the leather finishes and systems that Stahl is offering are water-based. Their dedicated R&D staff focuses on developing eco-based substitute components without compromising on the quality of the final product. The variations in finishes are endless and next to their own product range Stahl provides customised finishes for their clients too.

There are a number of specialist machines for finishing the leather too:

• Cabins for manual finishing system / Spray guns
• Drying cabinets
• Reverse and Synchro roller coating machines
• Static embossing press with different types of plates
• Roto-press: Continuous press for ironing, burnishing and polishing leather
• Polishing machine
• Foam generator for water based systems
• Weighing equipment
• Cabinet for flammable products

Unique patent machine

This machine is quite unique and the only one available within Stahl! Using Stahl chemicals it can create a very high gloss maintaining a pleasant luxurious feel using a transparent and flexible film. The patents created with this machine are also lightfast for white and pastel shades.

Curtain coater for solvent patent system: modern semi-production line equipment for patent leather finishes. The excess of product is re-pumped and reused with very little loss of material.

Drying room for patent; Application room has air flow and temperature control

Physical test performed specific to patent leather:

• Thermosetting, to measure tear strength of the hole of the sewing during mold of the shoe
• Flexes: to measure flexibility of the finishes in different conditions; wet, dry and cold
• Adhesion: to measure adhesion between basecoat and patent leather top coat in different conditions: wet and dry
• Recovery to solvent exposure (acetone): to measure damage in the finished patent leather, applying acetone on the flesh side.
• Cold crack: to measure resistance of the patent leather top coat in hard impact, at cold temperatures

     

Machines of the CoE for Performance Coatings (Non leather)

A performance coating is a product finish that upgrades virtually any type of synthetic, textile or paper surface that is either flexible or rigid. It’s technology that makes materials endure the elements, scratch resistant, durable, beautiful, fashionable and comfortable.

 Sintex Coating Machine:

• Transfer and direct coating machine, 50 cm width for transfer (on paper), 60cm width for direct coating.
• It is possible to apply by knife on cylinder, knife on air, reverse roll, synchro and by dipping,
• It is possible to do dry and wet lamination.

Sintex embossing machine:

• Able to emboss up to 40 cm widths, with different grains, by hot cylinder and with IR radiation/cold cylinder.
• Enables textile lamination and film lamination (like metallic film, transfer printing etc…)

Isotex coating machine:

• Transfer coating machine with 35 cm width on transfer coating paper, it is also possible to do some direct coating on the textile (just no elastic substrates). This machine also allows the embossing of small samples with IR radiation and cold cylinder.
• Just wet lamination it is possible.

Sintex SCL 300 and Jolly coat:

• Transfer and direct coating machines for DIN A4 samples.

Teamcoat printing machine:

• Rotogravure printing machine with different cylinders available, for lacquer application (application capacity from 5-8 g/sm till 30.-35 g/sm wet).

Roller printing machine:

• Synchro and revers printing machine, it is possible to apply with different cylinder from very few g/sm up to 100-150 g/sm.
• Allows the application of bi-tone effects.