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JCE Clothing and Textiles study materials
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JCE Clothing and Textiles practice questions

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Question 1Fibres, Yarns and Fabric Construction

Which natural fibre is classified as a bast fibre obtained from the stem of its plant?

  1. Flax Correct answer.
  2. Silk
  3. Cotton
  4. Wool

Explanation

Bast fibres are sclerenchyma fibres harvested from the phloem region of plant stems, and flax (linen) is the classic example, alongside hemp, jute and ramie. Cotton is a seed hair, while wool and silk are animal proteins.

Question 2Fibres, Yarns and Fabric Construction

Which property of the cotton fibre most directly explains its good moisture absorbency?

  1. Its natural spiral crimp
  2. Its low elastic recovery
  3. The many hydroxyl groups along its cellulose chains Correct answer.
  4. Its high degree of polymerisation

Explanation

Cellulose is a polysaccharide rich in hydroxyl groups that form hydrogen bonds with water, drawing moisture into the amorphous regions. Crimp, polymer length and elastic recovery affect bulk, strength and wrinkle behaviour rather than absorbency directly.

Question 3Fibres, Yarns and Fabric Construction

In yarn manufacture, what does the term 'twist multiplier' describe?

  1. The direction of spindle rotation
  2. The number of plies twisted together
  3. The percentage of waste removed during combing
  4. The ratio of twist per unit length to the square root of yarn count Correct answer.

Explanation

Twist multiplier expresses twist level independent of yarn thickness, typically as turns per inch divided by the square root of the cotton count. This allows the same 'feel' of twist to be compared across different yarn counts.

Question 4Fibres, Yarns and Fabric Construction

Which weave produces the smoothest, most lustrous surface because the yarns float over several of the opposite set before interlacing?

  1. Basket weave
  2. Twill weave
  3. Satin weave Correct answer.
  4. Plain weave

Explanation

In a satin weave, interlacing points are spaced so that long floats of warp or weft lie on the surface, reflecting light and giving a smooth, lustrous face. Plain and basket weaves interlace frequently, and twill gives a diagonal rib.

Question 5Fibres, Yarns and Fabric Construction

Which fibre is a regenerated cellulosic fibre produced by the viscose process?

  1. Viscose rayon Correct answer.
  2. Acetate
  3. Polyester
  4. Nylon 6,6

Explanation

Viscose rayon is made by converting wood pulp cellulose into cellulose xanthate, then regenerating it in an acid bath. Acetate is also cellulosic but is an esterified derivative rather than regenerated cellulose, and polyester and nylon are synthetic polymers.

Question 6Fibres, Yarns and Fabric Construction

A singles cotton yarn has a twist direction of 'Z'. What does this indicate about the spindle rotation as seen by the operator?

  1. Clockwise rotation, giving a diagonal that slopes like the letter Z Correct answer.
  2. No twist inserted, only false twist
  3. Anti-clockwise rotation, giving a diagonal that slopes like the letter S
  4. Alternating direction along the yarn length

Explanation

Twist direction is named after the slope of the helix: a Z-twist runs bottom-left to top-right, produced by clockwise spindle rotation in the usual spinning arrangement. S-twist is the mirror image.

Question 7Fibres, Yarns and Fabric Construction

Which of the following is a filament fibre in its natural state?

  1. Wool
  2. Silk Correct answer.
  3. Flax
  4. Cashmere

Explanation

The silkworm extrudes a continuous protein filament that is reeled directly from the cocoon, so silk is naturally filamentous. Wool, cashmere and flax are all staple fibres of limited length that must be spun.

Question 8Fibres, Yarns and Fabric Construction

Which fabric structure is made by interlocking loops of yarn so that a single broken thread can run and unravel the whole piece?

  1. Nonwoven
  2. Woven
  3. Knitted Correct answer.
  4. Braided

Explanation

Knitted fabric consists of intermeshed loops, and because each loop depends on its neighbours, a break can cause a ladder or run. Woven and braided structures use interlacing or diagonal crossing, and nonwovens use bonded webs rather than loops.

Question 9Fibres, Yarns and Fabric Construction

A spinner wishes to produce a smoother, stronger, more uniform cotton yarn with fewer short fibres and less neps. Which preparation route should be selected?

  1. Carding followed by combing Correct answer.
  2. Carding only
  3. Rotor spinning from carded sliver
  4. Opening and blending only

Explanation

Combing removes short fibres and neps and aligns the remaining long fibres, producing a finer, smoother and stronger combed yarn. Carding alone opens and cleans the fibre but leaves short fibres in the sliver.

Question 10Fibres, Yarns and Fabric Construction

Why does a 100% viscose rayon garment lose strength markedly when wet, unlike cotton?

  1. Rayon contains no hydroxyl groups
  2. Rayon fibres shrink irreversibly on wetting
  3. Rayon absorbs no water and becomes brittle
  4. Rayon has a lower degree of polymerisation and lower crystallinity, so water disrupts the amorphous regions Correct answer.

Explanation

Regenerated cellulose has shorter chains and lower crystallinity than cotton, so water penetrates the amorphous regions and reduces hydrogen bonding between chains, lowering wet strength. Cotton's higher crystallinity protects its strength when wet.

Question 11Fibres, Yarns and Fabric Construction

A manufacturer needs a lightweight fabric with good drape and a soft handle for a summer blouse. Which combination of yarn and weave best meets the requirement?

  1. Fine combed cotton yarn in a tight plain weave
  2. Fine filament yarn in a plain weave with low cover factor Correct answer.
  3. Bulked acrylic yarn in a double cloth
  4. Coarse woollen yarn in a 3/1 twill

Explanation

Fine filament yarns allow a low cover factor plain weave, producing a light, flexible cloth that drapes well. Tight plain weaves and coarse twills add weight and stiffness, while double cloth is deliberately thick.

Question 12Fibres, Yarns and Fabric Construction

Which spinning system is most suitable for producing a fine, strong yarn from short-staple cotton at high speed using a traveller and ring?

  1. Friction spinning
  2. Wrap spinning
  3. Ring spinning Correct answer.
  4. Woollen mule spinning

Explanation

Ring spinning drafts the roving, inserts twist with a traveller on a ring and winds the yarn, giving fine, strong, versatile yarns from short staple. Wrap and friction systems generally produce coarser or differently structured yarns.

Question 13Fibres, Yarns and Fabric Construction

In a 2/60s cotton count yarn, what does the designation indicate?

  1. A 2 tex filament yarn
  2. A single yarn of 60 tex
  3. A yarn with 60 twists per inch
  4. Two plies of 60s count singles Correct answer.

Explanation

The first figure gives the number of plies and the second the count of each singles component, so 2/60s means two plies of 60s cotton count. The resultant count is found by dividing 60 by 2, giving 30s.

Question 14Fibres, Yarns and Fabric Construction

Which feature distinguishes a twill weave from a plain weave in terms of yarn interlacing?

  1. Long floats occur only on the face
  2. Two warps and two wefts interlace as one
  3. Every warp and weft interlaces alternately
  4. The interlacing points form a diagonal line across the cloth Correct answer.

Explanation

Twill weave offsets the interlacing points by one or more ends in each successive pick, producing a continuous diagonal rib. Plain weave alternates every yarn, and basket weave doubles the yarns in a plain arrangement.

Question 15Fibres, Yarns and Fabric Construction

Why are wool fibres able to felt, whereas cotton fibres generally cannot?

  1. Wool has a scaly cuticle and natural crimp that interlock under moisture, heat and agitation Correct answer.
  2. Cotton has a higher moisture regain than wool
  3. Wool contains no disulphide bonds
  4. Cotton fibres lack a lumen

Explanation

The overlapping scales on the wool surface, combined with crimp and the fibre's ability to deform under moisture and heat, allow fibres to migrate and entangle irreversibly, producing felt. Cotton's smooth, ribbon-like surface does not provide the same directional interlocking.

Question 16Fibres, Yarns and Fabric Construction

A loom produces a fabric in which the weft yarns are much coarser and more widely spaced than the warp. Which fabric property is most likely to result?

  1. Reduced air permeability
  2. Higher weft-way strength than warp-way strength
  3. Equal strength in both directions
  4. Higher warp-way strength than weft-way strength Correct answer.

Explanation

Strength in a woven fabric follows the yarns and their density in each direction, so finer, more numerous warp yarns give greater warp-way strength. Coarser, more widely spaced weft yarns give lower weft-way strength and also increase air permeability.

Question 17Fibres, Yarns and Fabric Construction

Which statement correctly describes the difference between a carded and a combed yarn?

  1. Combing removes long fibres and keeps the short ones
  2. Combed yarns have fewer short fibres and more parallel fibres, giving higher strength and lustre Correct answer.
  3. Carded yarns are always finer than combed yarns
  4. Combed yarns retain more short fibre and are therefore rougher

Explanation

Combing removes short fibres, neps and impurities and straightens the remaining long fibres, so combed yarns are smoother, stronger and more lustrous. Carded yarns keep a full fibre distribution and are generally coarser.

Question 18Fibres, Yarns and Fabric Construction

Why is polyester frequently blended with cotton in a 65/35 ratio for shirting?

  1. Polyester contributes strength, crease recovery and quick drying while cotton contributes absorbency and comfort Correct answer.
  2. The blend makes the fabric fully flame retardant
  3. The blend lowers the melting point of the fabric
  4. Polyester improves absorbency while cotton improves crease recovery

Explanation

In a polyester/cotton blend, the synthetic component adds tensile strength, wrinkle resistance and fast drying, while cotton adds moisture absorbency and a comfortable handle next to the skin. The combination balances performance and comfort.

Question 19Fibres, Yarns and Fabric Construction

Which yarn structure gives a stretch yarn by combining a hard core filament with a helically wrapped fibre sheath?

  1. Folded yarn
  2. Slub yarn
  3. Cabled yarn
  4. Core-spun yarn Correct answer.

Explanation

A core-spun yarn wraps staple fibres around a central filament core, which may be elastomeric, so the yarn can stretch while retaining a spun-fibre surface. Folded and cabled yarns combine plies without a distinct core.

Question 20Fibres, Yarns and Fabric Construction

A manufacturer wants a fabric with high tear strength for workwear. Which change to a plain-weave construction would most improve tear resistance?

  1. Reducing yarn-to-yarn friction by using longer floats and a lower sett Correct answer.
  2. Increasing the number of interlacing points
  3. Increasing the twist multiplier substantially
  4. Using finer yarns at a higher sett

Explanation

Tear strength improves when yarns can slide and group together at the tear, which is favoured by longer floats and a lower sett. More interlacing points and higher twist lock the yarns and concentrate stress, reducing tear resistance.

Question 21Fibres, Yarns and Fabric Construction

Which statement about the moisture regain of textile fibres is correct?

  1. Polyester has a higher regain than wool at standard conditions
  2. Regain is independent of relative humidity
  3. All synthetic fibres have zero regain
  4. Wool has a higher regain than polyester at standard conditions Correct answer.

Explanation

Wool is hygroscopic, with a standard regain of roughly 13 to 16 per cent, whereas polyester is hydrophobic with a regain of well under one per cent. Regain rises with relative humidity for all fibres that absorb moisture.

Question 22Fibres, Yarns and Fabric Construction

A three-harness twill is described as a 2/1 twill. What does this mean?

  1. Two picks weave one, giving a warp-faced twill Correct answer.
  2. Two warp yarns are missing from each repeat
  3. One pick weaves two, giving a weft-faced twill
  4. The twill angle is 21 degrees

Explanation

In a 2/1 twill each weft passes over two warp ends and under one, so warp floats dominate the face and the cloth is warp-faced. The twill angle depends on the sett ratio, not on this notation.

Question 23Fibres, Yarns and Fabric Construction

A yarn of 40s cotton count is required. Given that 1 tex equals approximately 590.5 divided by the cotton count, which tex value is closest?

  1. 59.0 tex
  2. 14.8 tex Correct answer.
  3. 40.0 tex
  4. 23.6 tex

Explanation

Using the conversion, tex equals 590.5 divided by the cotton count, so 590.5 divided by 40 gives about 14.8 tex. This reflects the inverse relationship between indirect cotton count and direct tex.

Question 24Fibres, Yarns and Fabric Construction

Why does a satin-weave fabric generally show lower abrasion resistance than a comparable plain-weave fabric?

  1. The long surface floats are easily snagged and abraded because few interlacing points anchor them Correct answer.
  2. Satin fabrics always use weaker fibres
  3. Satin weaves contain more interlacing points per unit area
  4. Plain weave has longer floats

Explanation

Satin's long floats are exposed on the surface and held at few points, so they snag and wear away readily under abrasion. Plain weave has many interlacing points that anchor each yarn, giving better resistance to surface wear.

Question 25Fibres, Yarns and Fabric Construction

A spinner observes that increasing twist beyond the optimum makes a singles yarn weaker. Which explanation is most accurate?

  1. Excess twist removes moisture from the fibre
  2. Excess twist reduces the number of fibres in the cross-section
  3. Excess twist reverses the direction of the yarn helix
  4. Excess twist causes the fibres to lie at too steep an angle to the yarn axis, so they contribute less to tensile strength Correct answer.

Explanation

As twist rises, fibres become more inclined to the yarn axis and their resistance to pulling is resolved less efficiently along that axis, so strength peaks at an optimum and then falls. Very high twist can also cause snarling and spiral effects.

Question 26Fibres, Yarns and Fabric Construction

A woven fabric is described as having a 'balanced' plain weave. What does this mean for the warp and weft yarns?

  1. The warp yarns are twice as coarse as the weft yarns but set at half the density.
  2. The weft yarns float over several warp yarns to create a ribbed surface.
  3. The warp and weft yarns are identical in linear density and set equally per unit length. Correct answer.
  4. The warp and weft yarns are both filament yarns rather than staple yarns.

Explanation

In a balanced plain weave the two yarn systems match in count (linear density) and in the number of threads per centimetre, so the crimp and cover are similar in both directions. This gives a symmetrical, even fabric with comparable strength along warp and weft. Imbalance in either count or sett produces a rib or stripe effect instead.

Question 27Fibres, Yarns and Fabric Construction

A knitted fabric is described as having a 'wale' direction. What does a wale correspond to in the fabric?

  1. A column of interlocking loops running along the length of the fabric. Correct answer.
  2. A single broken yarn end that has caused a ladder.
  3. The diagonal path taken by a weft yarn in a twill weave.
  4. A horizontal row of loops running across the width of the fabric.

Explanation

In a knitted structure, a wale is a vertical column of intermeshed loops running in the direction the fabric is produced, analogous to a warp line. The horizontal counterpart is the course, a row of loops across the width. Recognising wales and courses is essential when judging knit density, stretch direction and grain.

Question 28Fibres, Yarns and Fabric Construction

A designer wants a woven fabric with a firm, close surface, minimal seam slippage and good dimensional stability for tailored trousers. Which construction choice best supports this?

  1. A loose plain weave using coarse single yarns at low sett.
  2. A single-jersey knit with a low loop density.
  3. A plain weave in a relatively high sett using two-ply yarns. Correct answer.
  4. A leno weave with widely spaced, paired warp yarns.

Explanation

A plain weave already gives the maximum number of interlacings per unit area, and increasing the sett plus using two-ply yarns further raises interlacement and yarn strength. The result is a firm, stable cloth that resists seam slippage and distortion in wear. Loose or open structures move in the opposite direction.

Question 29Fibres, Yarns and Fabric Construction

A buyer requests a fabric that stretches comfortably in both directions for close-fitting sportswear. Which yarn or fabric route is most appropriate?

  1. A tightly sett plain-weave fabric woven from two-ply cotton yarns.
  2. A heavily sized warp-faced fabric with high warp density.
  3. A weft-knitted fabric incorporating elastomeric yarn, giving stretch along wales and courses. Correct answer.
  4. A leno-weave fabric with paired, twisted warp yarns.

Explanation

Weft knitting is inherently extensible because loop shape can deform, and adding an elastomeric yarn such as elastane increases recovery and two-way stretch. This combination suits close-fitting activewear where movement and shape retention are needed. Woven structures without elastane offer little inherent stretch.

Question 30Fibres, Yarns and Fabric Construction

Two plain-weave cotton fabrics have the same yarn count and sett, but fabric A uses combed yarns and fabric B uses carded yarns. Which outcome is most consistent with the effect of combing on yarn and fabric performance?

  1. Fabric B has higher strength because carding aligns fibres more parallel.
  2. Fabric B shows better lustre because carding removes more neps.
  3. Fabric A is bulkier and warmer because combing retains more short fibres.
  4. Fabric A is smoother, stronger and less hairy, with fewer thin and thick places. Correct answer.

Explanation

Combing removes short fibres, neps and trash and further parallelises the fibre assembly, so the resulting yarn is more even, stronger and smoother with less protruding fibre. In an identical weave and sett, that translates into a cleaner, stronger fabric surface. Carding alone leaves more short fibre and irregularity.

Question 31Fabric Finishes, Dyeing and Printing

Which finish is applied to cotton fabric to improve its smoothness, luster and dye uptake by swelling the fibres with sodium hydroxide under tension?

  1. Calendering
  2. Mercerisation Correct answer.
  3. Carbonisation
  4. Sanforisation

Explanation

Mercerisation treats cellulosic fabric or yarn with concentrated sodium hydroxide while held under tension. The fibres swell, become rounder and more lustrous, and take dye more readily. Calendering and sanforisation are mechanical processes, and carbonisation removes vegetable matter from wool.

Question 32Fabric Finishes, Dyeing and Printing

In textile dyeing, which term describes a dye's ability to migrate from the fibre surface into the fibre interior and distribute evenly?

  1. Exhaustion
  2. Migration Correct answer.
  3. Strike
  4. Substantivity

Explanation

Migration is the movement and redistribution of dye within the fibre after adsorption, and good migration promotes level dyeing. Strike relates to the rate of initial dye uptake, exhaustion to the proportion of dye transferred to the fibre, and substantivity to the affinity between dye and fibre.

Question 33Fabric Finishes, Dyeing and Printing

Which printing method produces a design by transferring dye from an engraved roller onto fabric, giving high production speed and fine detail for long runs?

  1. Flat-bed screen printing
  2. Roller printing Correct answer.
  3. Rotary screen printing
  4. Transfer printing

Explanation

Roller printing uses engraved copper rollers to transfer dye paste onto the fabric, allowing very fine detail and high speeds for long production runs. Screen printing uses mesh screens, and transfer printing uses sublimation from paper.

Question 34Fabric Finishes, Dyeing and Printing

Which finish is specifically designed to reduce the flammability of a fabric by interrupting the combustion cycle?

  1. Anti-static finish
  2. Soil-release finish
  3. Water-repellent finish
  4. Flame-retardant finish Correct answer.

Explanation

Flame-retardant finishes work by interrupting combustion through mechanisms such as char formation, heat absorption or dilution of combustible gases. Water-repellent, anti-static and soil-release finishes address wetting, static charge and stain removal respectively.

Question 35Fabric Finishes, Dyeing and Printing

Which class of dye is most commonly applied to cotton using a reducing agent such as sodium hydrosulphite followed by oxidation to develop the colour?

  1. Acid dyes
  2. Vat dyes Correct answer.
  3. Basic dyes
  4. Disperse dyes

Explanation

Vat dyes are applied to cellulosic fibres in their reduced, water-soluble leuco form and are then oxidised back to the insoluble pigment within the fibre. Acid and basic dyes are mainly for protein or acrylic fibres, and disperse dyes for synthetics.

Question 36Fabric Finishes, Dyeing and Printing

Which fabric preparation process removes natural waxes, pectins and oils from cotton to allow uniform dye penetration?

  1. Bleaching
  2. Scouring Correct answer.
  3. Singeing
  4. Desizing

Explanation

Scouring uses alkaline solutions to remove natural waxes, pectins, oils and dirt, making cotton absorbent and ready for uniform dyeing. Desizing removes added size, bleaching removes colour, and singeing burns off surface hairs.

Question 37Fabric Finishes, Dyeing and Printing

A printer wants a discharge-printed design on a dark dyed cotton ground. Which description best explains how discharge printing achieves the pattern?

  1. A pigment binder is applied on top of the dyed fabric to cover the ground colour.
  2. A resist paste prevents dye from entering selected areas during dyeing.
  3. A printing paste containing a reducing agent destroys the ground dye in selected areas. Correct answer.
  4. A disperse dye is sublimed from transfer paper onto the fabric surface.

Explanation

Discharge printing applies a paste containing a discharging agent that chemically destroys the ground colour in the printed areas, revealing a lighter design. Resist printing prevents dye uptake, while pigment and transfer methods add colour rather than remove it.

Question 38Fabric Finishes, Dyeing and Printing

A manufacturer needs a cotton fabric with reduced shrinkage after repeated laundering. Which process should be specified?

  1. Calendering
  2. Mercerisation
  3. Schreiner calendering
  4. Sanforisation Correct answer.

Explanation

Sanforisation mechanically compresses and stabilises cotton fabric to limit residual shrinkage to a controlled low level. Calendering and Schreiner calendering press the surface for smoothness, and mercerisation improves lustre and dye uptake rather than controlling shrinkage.

Question 39Fabric Finishes, Dyeing and Printing

Which dyeing method is most suitable for a small batch of woollen knitwear where gentle handling and level dyeing are priorities?

  1. Continuous pad-steam dyeing
  2. Winch or beck dyeing Correct answer.
  3. Beam dyeing
  4. Jig dyeing

Explanation

Winch or beck dyeing handles fabric in rope form in an open bath, allowing gentle movement and good levelness for delicate knitwear. Jig and beam dyeing apply tension, and continuous pad-steam is suited to large volumes of flat fabric.

Question 40Fabric Finishes, Dyeing and Printing

A fabric is described as having a 'calendered' finish. Which property is most directly improved by this treatment?

  1. Flame resistance
  2. Colour fastness to washing
  3. Resistance to static charge
  4. Smoothness and luster Correct answer.

Explanation

Calendering passes fabric between heated rollers under pressure, flattening the surface to improve smoothness, luster and handle. It does not impart flame resistance, anti-static behaviour or wash fastness.

Question 41Fabric Finishes, Dyeing and Printing

Why is a substantivity test useful before bulk dyeing a new fibre blend?

  1. It measures the tensile strength of the dyed fabric after washing.
  2. It calculates the cost of dye per kilogram of fabric.
  3. It determines the colour fastness rating to light exposure.
  4. It predicts the affinity of the dye for the fibre and helps select a compatible dye class. Correct answer.

Explanation

Substantivity testing indicates how strongly a dye is attracted to a given fibre, guiding the choice of dye class and recipe. It is not a strength, light fastness or cost calculation.

Question 42Fabric Finishes, Dyeing and Printing

Which printing technique uses a thick paste that is squeezed through a mesh screen, with one screen required for each colour?

  1. Digital printing
  2. Block printing
  3. Roller printing
  4. Screen printing Correct answer.

Explanation

Screen printing forces paste through a mesh screen with a squeegee, and a separate screen is used for each colour. Roller printing uses engraved rollers, block printing uses carved blocks, and digital printing uses inkjet heads.

Question 43Fabric Finishes, Dyeing and Printing

A customer complains that a dark navy cotton garment fades unevenly after washing. Which dyeing defect is most likely responsible?

  1. Excessive scouring before dyeing
  2. Poor migration leading to unlevel dyeing Correct answer.
  3. Over-bleaching of the fabric
  4. Incorrect singeing temperature

Explanation

Unlevel dyeing often results from poor migration, where dye does not redistribute evenly within the fibre, so fading appears patchy. Scouring and bleaching prepare the fabric but do not cause uneven fading, and singeing affects surface hairs only.

Question 44Fabric Finishes, Dyeing and Printing

Which finish would be selected to allow a cotton/polyester shirt to release oily stains more easily during home laundering?

  1. Soil-release finish Correct answer.
  2. Flame-retardant finish
  3. Water-repellent finish
  4. Stiffening finish

Explanation

Soil-release finishes modify the fibre surface so that oily soils detach and wash away more readily. Water-repellent and flame-retardant finishes address wetting and combustion, and stiffening affects handle.

Question 45Fabric Finishes, Dyeing and Printing

Which statement correctly distinguishes pigments from dyes in textile coloration?

  1. Pigments are insoluble and are fixed to the surface with a binder, whereas dyes have affinity for the fibre. Correct answer.
  2. Pigments are soluble in water and penetrate the fibre, whereas dyes remain on the surface.
  3. Pigments require a reducing agent, whereas dyes require oxidation.
  4. Pigments are used only on wool, whereas dyes are used only on cotton.

Explanation

Pigments are insoluble colourants with no inherent affinity for fibres, so they are applied with a binder that adheres them to the surface. Dyes are generally soluble or dispersible and have substantivity for specific fibres.

Question 46Fabric Finishes, Dyeing and Printing

In a pad-dry-cure process for a durable-press finish, which sequence of operations is correct?

  1. Dry, pad with resin, then singe
  2. Cure at elevated temperature, then pad with resin, then dry
  3. Pad with resin, dry, then cure at elevated temperature Correct answer.
  4. Pad with resin, cure, then wash without drying

Explanation

The pad-dry-cure sequence applies the resin by padding, removes moisture by drying, and then cures at elevated temperature to crosslink the resin with the cellulose. Curing before padding or omitting drying would prevent proper fixation.

Question 47Fabric Finishes, Dyeing and Printing

A polyester fabric is to be dyed with disperse dyes. Which condition is most important for achieving deep, fast shades?

  1. Anionic dye sites on the fibre
  2. A reducing agent to solubilise the dye
  3. High temperature under pressure to open the fibre structure Correct answer.
  4. Strongly acidic conditions to protonate the fibre

Explanation

Polyester is hydrophobic and tightly packed, so disperse dyes require high temperature, often above 100 degrees Celsius under pressure, to swell the fibre and allow dye diffusion. Acidic conditions and reducing agents relate to other dye classes, and polyester lacks ionic dye sites.

Question 48Fabric Finishes, Dyeing and Printing

A screen-printed design shows a sharp, hard edge on one side and a blurred, bleeding edge on the other. Which cause is most plausible?

  1. Excessive dye fixation after printing
  2. Incorrect fibre blend ratio in the fabric
  3. Inconsistent squeegee pressure or screen registration during printing Correct answer.
  4. Use of a pigment rather than a dye

Explanation

Uneven squeegee pressure or poor registration causes paste to be deposited unevenly, producing sharp edges on one side and bleeding on the other. Fixation, blend ratio and colourant type do not explain a one-sided edge defect.

Question 49Fabric Finishes, Dyeing and Printing

Which combination best explains why a resin-finished cotton fabric may lose strength?

  1. Crosslinking restricts fibre movement and reduces elongation and tensile strength Correct answer.
  2. The resin adds weight that physically crushes the fibres
  3. The curing step removes natural waxes from the fibre
  4. The resin increases moisture regain and swells the fibre

Explanation

Durable-press resins crosslink cellulose chains, restricting chain movement and reducing elongation, which lowers tear and tensile strength. The loss is a chemical/structural effect, not crushing, wax removal or swelling.

Question 50Fabric Finishes, Dyeing and Printing

A dyer observes that a reactive dye batch on cotton shows poor colour yield despite correct dye weight. Which factor is most likely to reduce fixation efficiency?

  1. Use of softened water in the dyebath
  2. Too long a fixation time at the recommended temperature
  3. Excessively high electrolyte concentration at the start
  4. Insufficient alkali to promote covalent reaction with cellulose Correct answer.

Explanation

Reactive dyes need alkali to activate cellulose hydroxyl groups and form covalent bonds; insufficient alkali lowers fixation and colour yield. Electrolyte promotes exhaustion, adequate time aids fixation, and softened water is generally beneficial.