Unit 3 Lecture 20 Topic 2

Question 1

How are non-woven fabrics manufactured?

Answer 1

There are two steps in the manufacturing of non-woven fabrics: 1. Preparing the fibre web
2. Bonding or entangling the fibres within the web
The method for preparation and bonding will depend on the type of fibre used.

Question 2

Dry-laid:

Answer 2

Staple fibres are carded into oriented webs, then stacked upon each other; or staple fibres are dispersed in the air in random fibre arrangement producing air-laid webs.

Question 3

Wet-laid Webs:

Answer 3

Made from a slurry of short fibres and water. Water is extracted leaving a randomly oriented fibre web similar to how paper is made.

Question 4

How are non-woven fibres held together?

Answer 4

Physical interlocking, heat bonding, adhesive bonding, or stitching through the fibre web.

Question 5

Tapa Cloth:

Answer 5

Also called bark cloth, these paper-like sheets are made from mulberry or fig bark and then soaked and beaten until soft.

Question 6

Felt:

Answer 6

Made from wool and other animal hair fibres, felting makes use of the scales and directional frictional effect of wool. Cleaned wool is carded and a web is formed by layering. Moisture, heat and pressure cause the fibres to interlock, shrink and felt.

Question 7

Needle Punching:

Answer 7

Entangling fibre webs with barbed needles. The structure is similar to felt, but can be made with any fibre type (not just wool).

Question 8

What is the durability of needle punching?

Answer 8

There is low strength and tearing resistance if the fibres are not thoroughly entangled.

Question 9

How can you tell if something is needle-punched?

Answer 9

There is obvious needle marks.

Question 10

What are the comfort properties of needle-punched products?

Answer 10

They are thick and lofty to provide insulation, while being air and moisture permeable.

Question 11

Spun-laced Webs:

Answer 11

Staple fibres, entangled by high-pressure water jets. Patterns can be created by using a perforated support. Medical gowns and drapes, mattress pads, and kitchen wipes are spun-laced.

Question 12

What is the durability of spun-laced webs?

Answer 12

They have good elasticity and flexibility.

Question 13

Spun-bonded webs:

Answer 13

Made as synthetic fibres are extruded from spinnerets and randomly laid down on a fast-moving conveyor belt. In their semi-molten state, the fibres fuse together at crossing points and then may be further bonded by heat and pressure.

Question 14

Why are spun-bonded webs good? What are they used for?

Answer 14

Spun bonded webs are the quickest, most economical method used for carpet backings, geotextiles, tents & tarps, bags, protective clothing, and filters.

Question 15

What is the durability of spun-bonded webs?

Answer 15

They have high tensile and tear strength.

Question 16

What are the comfort properties of spun-bonded webs?

Answer 16

They have low bulk, making them lightweight and air permeable.

Question 17

Melt-blown Webs:

Answer 17

Fibres are extruded from spinnerets and high speed and high temperature air breaks the fibres into short pieces. The fibres are then collected on a conveyor belt in a semi-molten state where they fuse together at crossing points. They may be further bonded by heat and pressure.

Question 18

What is the durability of melt-blown items?

Answer 18

The fibres are undrawn, randomly oriented and weak so the strength is lower than spun-bonded webs.

Question 19

Adhesive Bonding:

Answer 19

A chemical adhesive can be used with dry-laid or wet-laid webs. The adhesive is applied in liquid, powder or foam and heated or set by chemical action.

Question 20

Stitch-bonding:

Answer 20

When fibres are held together by stitching with additional yarn or thread.