CCT Carpet Fiber Identification & Construction 4 — Questions and Answers
Question 1: A customer's carpet turns yellow after cleaning. The most likely cause when the fiber is wool is:
- Over-wetting with cold water
- Use of an acidic pre-spray below pH 4
- Residual alkaline cleaner reacting with wool protein (Correct answer)
- Use of an enzyme-based spotter
Correct answer: Residual alkaline cleaner reacting with wool protein
Alkaline residue left on wool oxidizes and causes yellowing; wool must always be rinsed to a near-neutral pH to prevent this reaction.
Question 2: Which carpet construction provides the best performance in high-traffic commercial settings?
- High-pile cut Saxony
- Dense, low-level loop or cut-loop commercial carpet (Correct answer)
- Shag or frieze with long fibers
- Woven Axminster with ornate patterns
Correct answer: Dense, low-level loop or cut-loop commercial carpet
Dense, low-level loop or commercial cut-loop carpets resist matting and crushing far better than high-pile constructions in heavy traffic.
Question 3: Triexta (PTT) fiber, used in brands like Mohawk SmartStrand, is derived from:
- 100% petroleum byproducts like nylon
- Partially from corn glucose (bio-based feedstock) (Correct answer)
- Recycled PET plastic bottles
- Natural wool and synthetic blend
Correct answer: Partially from corn glucose (bio-based feedstock)
Triexta (PTT) is partially bio-based, with about 37% derived from corn glucose (PDO), distinguishing it from fully petroleum-based synthetics.
Question 4: What is the purpose of the secondary backing on a tufted carpet?
- To hold dye in the fiber during manufacturing
- To add dimensional stability and improve adhesion for installation (Correct answer)
- To increase the softness of the carpet face
- To provide the primary surface for foot traffic
Correct answer: To add dimensional stability and improve adhesion for installation
Secondary backing (usually jute or action-bac polypropylene) is laminated to the primary backing to add stability, stiffness, and better bond for adhesive installation.
Question 5: Which test best identifies silk carpet fiber in the field?
- Water drop test — silk absorbs water instantly unlike synthetics
- Burn test — silk burns slowly, smells like hair, leaves crushable ash, and feels cool to touch when held (Correct answer)
- Bleach test — silk turns white when bleach is applied
- Stretch test — silk has far more elasticity than any other fiber
Correct answer: Burn test — silk burns slowly, smells like hair, leaves crushable ash, and feels cool to touch when held
Silk burns like wool (protein fiber), smelling of burning hair with a crushable ash, and has a characteristic cool, smooth feel that helps distinguish it from synthetics.
Question 6: What does 'heat-setting' accomplish in cut pile carpet yarn production?
- It dyes the fiber in the yarn bundle
- It locks the twist in the yarn so tips resist unraveling under traffic (Correct answer)
- It bonds the primary and secondary backing together
- It applies a stain-resist treatment to the fiber surface
Correct answer: It locks the twist in the yarn so tips resist unraveling under traffic
Heat-setting uses steam or dry heat to 'memorize' the yarn twist so the fiber tips remain tightly curled instead of spreading open when walked on.
Question 7: A carpet labeled '100% BCF nylon' means the fiber is:
- Bonded, coated, and fused — a three-step manufacturing process
- Bulked continuous filament — long continuous strands (not staple fiber) (Correct answer)
- Bleach-compatible fiber — safe for chlorine bleach spotting
- Basic commercial-formula nylon for contract use only
Correct answer: Bulked continuous filament — long continuous strands (not staple fiber)
BCF stands for Bulked Continuous Filament, meaning the fiber is one long continuous strand that is bulked (crimped) for softness, as opposed to short-staple spun fiber.
CCT Carpet Fiber Identification & Construction 4
A customer's carpet turns yellow after cleaning.
The most likely cause when the fiber is wool is: