Question

The twist per inch (TPI) of a yarn primarily affects its:

• A. Fineness
• B. Strength
• C. Length
• D. Moisture regain

Hint:

Yarn strength increases with twist up to an optimum level; beyond that point, excessive twist can reduce strength due to fibre damage.

Answer 1

The Correct Option is B

The twist per inch (TPI) of a yarn is a critical factor that influences its physical properties. Let's analyze how the TPI affects various characteristics of yarn:

• Fineness: The fineness of a yarn is related to the diameter or thickness of the yarn. TPI does not directly affect the fineness. Fineness is typically determined by the fiber type and count.
• Strength: The strength of a yarn is significantly influenced by its twist. Increasing the TPI generally enhances the tensile strength of the yarn as it helps in better interlocking of fibers, which provides added cohesion and mechanical strength. Thus, TPI primarily affects the yarn's strength.
• Length: The length of the yarn is independent of its TPI. Length is a measure of how long the yarn is and does not vary with the amount of twist.
• Moisture Regain: Moisture regain is a measure of the amount of moisture yarn can absorb and retain. This property is primarily a function of the fiber material used in the yarn and is not affected by the twist per inch.

Based on this analysis, the correct answer is that the twist per inch (TPI) of a yarn primarily affects its Strength.