UPMSP Vocational Laundry & Dyeing flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Sinner's circle

A model showing that mechanical action, temperature, chemical action and time together determine cleaning. Increasing one factor allows reducing another, which protects delicate fibres.

Protein stain rule

Blood, egg, milk and grass contain protein that coagulates with heat. Wash them in cool water with enzyme detergent before any hot treatment, or the stain sets permanently.

Tannin stain treatment

Tea, coffee, wine and fruit contain tannins removed with hot water and a mild acid such as dilute acetic acid. Alkaline agents first can fix the colour.

Rust stain removal

Rust is removed with oxalic acid or a proprietary rust remover followed by thorough rinsing. Chlorine bleach must never be used, because it fixes rust permanently.

Spotting direction rule

Work from the back of the fabric over an absorbent pad, moving from the outside of the stain inward. This prevents the stain spreading and forming a ring.

Burn test cotton

Cotton burns quickly with the smell of burning paper, leaves soft grey ash and does not melt. The ash crumbles easily between the fingers.

Burn test wool

Wool and silk burn slowly, self-extinguish, smell of burnt hair and leave a crushable black bead. Silk is smoother and finer than wool.

Burn test polyester

Polyester melts and shrinks away from the flame with a sweet chemical odour and leaves a hard, dark bead that cannot be crushed.

Viscose wet strength

Regenerated cellulose fibres such as viscose lose roughly 40-50 percent of their strength when wet. They must not be rubbed, wrung hard or hung wet.

Satin weave

A weave with long floats producing high lustre and smoothness, but low abrasion resistance because the floats are easily snagged and worn.

Anionic surfactants

Negatively charged surfactants with strong oily-soil removal and high foaming, widely used in laundry powders for cotton. They perform poorly in very hard water without builders.

Non-ionic surfactants

Uncharged surfactants with low foam and good performance on synthetic fibres and at low temperature. They suit front-loading machines and automatic dosing systems.

Detergent builders

Substances that soften water and supply alkalinity, such as sodium carbonate, sodium silicate, zeolites and citrates. They prevent soap scum and improve surfactant efficiency.

Washing enzymes

Substrate-specific proteins: protease for protein, amylase for starch, lipase for fat, cellulase for surface fuzz. They work best at 30-50 degrees Celsius and are destroyed by heat.

Optical brightener

A fluorescent dye that absorbs ultraviolet light and re-emits blue light, making white fabric look brighter. It does not remove soil or bleach anything.

Wash cycle sequence

The standard order is pre-wash or flush, main wash with detergent, rinse, fabric conditioner in the final rinse, then extraction by spinning.

Load drum rule

Load the drum to roughly 80 percent of its volume so fabrics can tumble and flex. Overloading prevents mechanical action, rinsing and detergent circulation.

Bleach mixing hazard

Chlorine bleach must never be mixed with acid or ammonia, because toxic chlorine gas is released. Oxygen bleach is the safer alternative for coloured and delicate items.

Front loader vs top loader

Front loaders tumble fabric with low water and low foam. Top loaders use an agitator with higher mechanical action and more water, which is harsher on delicate fabrics.

Iron temperature order

From lowest to highest: acetate, silk, wool, polyester, cotton, linen. Labels use one dot for about 110, two for 150 and three for 200 degrees Celsius.

Pressing versus ironing

Ironing slides the iron over the fabric. Pressing applies the iron with downward pressure and lift, setting shape and creases with less distortion of the weave.

Pressing cloth use

A cloth placed between iron and fabric to reduce direct heat and prevent shine or glazing, especially on wool, dark synthetics and embellished garments.

Exhaustion and fixation

Exhaustion is the share of dye transferred from bath to fibre. Fixation is the share locked into the fibre chemically or physically. High exhaustion does not guarantee high fixation.

Salt in cellulose dyeing

Sodium chloride or sulphate added to direct and reactive dye baths reduces the electrical barrier between dye and cellulose, promoting exhaustion and deeper shade.

Reactive dye fixation

Reactive dyes form covalent bonds with cellulose hydroxyl groups in alkaline conditions, usually with soda ash. Unfixed dye must be soaped off to reach full wash fastness.

Vat dye principle

Insoluble vat dyes such as indigo are reduced to a soluble leuco form in alkaline sodium hydrosulphite, applied to cellulose, then oxidised back to insoluble pigment inside the fibre.

Disperse dyes

Sparingly soluble dyes applied as a fine dispersion, mainly to polyester at about 130 degrees Celsius under pressure. They are the practical class for hydrophobic synthetic fibres.

Cold pad-batch dyeing

Fabric is padded with reactive dye and alkali, then batched at room temperature for 12-24 hours. It saves energy and suits small production runs.

Metamerism in shade matching

Two samples that appear the same colour under one light source but differ under another. Shade matching must be done under standard daylight or a D65 lamp.

Care label iron dots

One dot means about 110 degrees Celsius for synthetics, two dots about 150 for wool and blends, three dots about 200 for cotton and linen.

Care label dry cleaning

A circle means professional dry cleaning is permitted. The letter inside, such as P, F or A, indicates the solvent class. A crossed circle means do not dry clean.

Break-even quantity

Fixed costs divided by the difference between unit price and unit variable cost. It gives the minimum order volume at which the business covers all its costs.

Order slip protection

A written slip signed by the customer, recording garment count and existing damage, is the main evidence protecting the laundry against disputed damage claims.