bath liquor: includes water (aqueous solutions) & chemicals (dyes, salt…)

chemical solutions revisited:

• solution = solute(s) + solvent

• one or more chemical substances (solute) dissolved in a liquid (solvent), typically water as the case for many chemical baths used for textile wet processing

• concentration can be defined as the measure of the amount of a substance (solute) present in given quantity of solvent or solution

• in textile processing, concentration refers to the proportion of chemicals, such as dyes, auxiliaries or finishing agents, in a solution, typically expressed in units such as grams per liter (g/L) or percentage (%)

• a 10% solution in the context of textile processing means that 10g of a chemical (solute) are dissolved in 90 mL of solvent (usually water) (total volume ~ 100mL)

• this can also be scaled up… 10kg of chemical in 90L of water (total volume ~ 100L)

• in this case, the concentration of the chemical is 10% of the total weight or volume of the solution, ensuring that for every 100 parts of the solution, 100 parts are the chemical of interest

IMPORTANT: DISTINGUISH BETWEEN BATCH VS CONTINUOUS PROCESSES ********

batch processes in general:

• process where the entire fabric/yarn soaks in a chemical bath and the chemicals move (”exhaust”) from the bath onto the surface of the fabric/yarn
• all the chemical bath is applied
• for batch processes to work, chemical must have some “affinity” for the fabric
• base calculations on % concentration on weight of fabric (OWF) or on weight of goods (OWG)