Prioritised target of the textile sector which is in constant development in order to comply with the changing technologies and consumption trends is to make production at the appropriate price and quality. The prerequisite of a quality production is to well determine the points to reach and act accordingly. In this context, control of the production processes and determining whether they occur as per order has currently gained importance.
Textile laboratories necessary for a good process control and quality production carry out raw material control, end product control, process control, R&D task and waste analyses and tests. Thanks to the processes in the textile laboratories that are divided into physical and chemical tests, products of desired qualities can be produced.
Physical Tests
Unshrinkability Test
Fabrics cut at the determined widths and lengths are made subject to washing at various temperatures, hung and tumble dried. In this way, shrinkage in the fabric sample is determined.
Fastness Tests
In the process where colour fastness to rubbing is measured, to what extent the dyed or printed products are resistant to encolouring as a result of rubbing with other textile products. In the dry rubbing fastness test, on the other hand, the dyed sample is placed on knock-meter. Dry white reference fabric is fixed to the clamp chamber in the device and the arm is operated. The colour passing to the white reference as a result of the pressure applied by the clamp chamber moving forward is compared to the gray scale indicating the staining degree. In the wet rubbing fastness test, the same procedures are followed. Only difference is the use of wet fabric instead of dry fabric.
In the Washing Fastness test where dyed textile material is fixed to the special reference fabric, the sample is placed into a bath where predetermined solutions exist is made to wait at the desired temperature. The sample is rinsed twice with distilled water and once with tap water after this process and compared to the fastness chart after the drying process.
Flammability Test
In the flammability test where inflammability and fire resistance and the properties of the fibre, yarn or fabric to catch fire, burn or go out after the ignition source gets away are measured, samples are made to contact the fire or heat-releasing objects.
Fibre Tests
Fibre types and ratios that should be specified in the labels of the products are controlled for compliance with the criteria envisaged by the purchase firms and correct compounds are detected.
Chemical Analyses
Gravimetric Analysis
It is based on precipitating one of the ions of the compound in the form of a poorly soluble and weighing it after a suitable concentrated solution is prepared with a known weight. The precipitated sample is weighed after it is accumulated in a sieve and dried. Gravimetry is a time-consuming and tiring method but it is certain. In the textile fibre analyses, one of the constituents is made to solve and the rest is weighed and the calculation is made.
Volumetric Analysis
In the volumetric analysis method, one of the ions in the weighing solution is determined with a standard solution of a suitable ion which is quantitative and reacts fast with this ion. Standard solution is added into the weighing solution which is mixed continuously until the end of the reaction via a partitioned and plug pipe called burette. The end of the reaction is determined via a suitable chemical indicator. The process of volumetry is called either titration or adjustment. As the substance amount that the standard solution titrates and measures 1 millimetre, the result of the volumetric analysis is easily calculated.
Instrumental Analysis
This is the analysis method used to detect the tiny quantities. It is divided into two as electrometric and optic. Examples of electrometric methods are conductimetry and potentiometry. While electrical conductivity of the solution is measured in conductimetry, changes in the electrical potential of the solution are measured in potentiometry. These two methods are very suitable for blurry solutions where indicator colour cannot be observed. The simplest example of optic methods is colorimetry which is used in the determination of concentrations of coloured solutions. With the simplest explanation, the colour of a solution whose concentration is known is compared to that of a solution whose concentration is not known.
Chromatography
This is the technique where soluble agents in the compound are dragged or migrate on an immobile phase with the help of mobile phase at various speeds. In this technique, agents of microgram level are trimmed and purified. Chromatographic methods are based on tiny differences between absorption and solution speeds of soluble agents.
Atomic Spectroscopy
Metal ions in the sample which is made a solution with the help of atomic spectroscopy can be determined. Metal ions are atomised at high flame temperature or via electrical flames and shifts are observed in the electronic energy levels of the atoms. Metal ions can be detected with sensitivity of 0.1 mg and several errors per thousand through the spectroscopy method based on transforming the metal ions in the samples that are made solutions into atom ions with the help of flames or electrical arc and creating shifts at the energy levels of the atoms.
Reference:
Umut Kıvanç Şahin, “Processes in the Textile Laboratories and Production”, İstanbul, 2013
A.R. Horrocks “Effects of alternative pre-treatments on performance of durable pres finished fabric" London, 2011
