Tuesday, November 13, 2018

FABRIC PROPERTIES PART - II

7- Tensile strength of fabric: when the stretching force (load) is applied to the fabric, it begins to elongate. The stretching force ( load) increases gradually, elongation also increases, when the amount of stretching force reaches on a certain point, the fabric begins to break. Now we can say that the tensile strength of the fabric is the amount of stretching force (load) at which the fabric begins to break when it comes under stretching conditions. It is measured in Newtons per square centimeter or pounds per square inch. It depends upon the yarn strength, material type or thread count per square of the fabric etc. the tensile strength of the fabric is determined separately in the warp and weft direction.
Synthetic fabrics have better tensile strength than natural fabrics.
The fabric made of fine and long staple fibers poses higher tensile strength than coarse and short fibers.
If the warp and the weft count of two fabrics are same, then the fabric having more threads per square inch will give higher tensile strength.

8 - Tearing strength of fabric: The term tearing strength of the fabric is the force which initiates the tearing in the fabric. “the tearing force required to initiate the tearing of the fabric from a split in the center of the specimen or continue tearing of the fabric” is called tearing strength of the fabric. It is also termed as tearing resistance. It is measured in pounds, grams, kilogram or Newton etc. it is determined for warp and weft direction separately. The factors influencing the tearing strength are:
 Type of material used in the fabric: The material used in the fabric greatly affects the tearing strength of the fabric. The fabric made of synthetic yarn has better tearing strength than natural fabric. The fabric made of continuous filament yarn has higher tearing strength than spun yarn. The fabric made of fine and long staple fibres has better-tearing strength than coarse and short staple fibres.
Yarn count and construction of the fabric:  the yarn count used in the fabric, ends per inch and picks per inch have great concern with tearing strength. It can be understood by some examples:
There are two fabrics say A and B, the GSM of both fabrics is identical. Fabric A is made of coarse count yarn and fabric B is made of fine count yarn. In this case, the tearing strength of the fabric A will be more than B.
If fabric A and B are made of same count and fabric A has more threads per square inch than B. In this situation, the fabric A will give better tearing strength than B.
Yarn twist: The yarn twist of the fabric influences the tearing strength up to some extent. High twist yarn in the fabric results in the form of improved tearing strength.
9 - Bursting strength:  when the fabric is subjected to pressure, the fabric begins to expand in all the possible directions at the same time. When the applied pressure increases gradually, the fabric begins to burst after a pressure limit. This pressure limit is called bursting strength. Thus we can say that “the pressure required to burst the fabric surface is termed as bursting strength of fabric”. It is measured in pounds (lbs.) per inch2 or kilograms per centimeter2. The bursting strength of the fabric is the very important property for parachute fabric. Type of yarn and material used in the fabric, the count and construction of the fabric.
 Material type influences the bursting strength of fabric greatly. The fabric woven with synthetic yarn has greater bursting strength than natural yarn.

10 - Crease resistance or crease recovery of fabric:  “The ability of the fabric to prevent the formation of wrinkles or creases on the surface of the fabric during various uses or process is called crease resistance of the fabric”. The crease resistance of the fabric is expressed in the term of crease recovery angle.
It greatly depends upon the type of material to be used in the fabric. The fabric made of synthetic material gives better crease resistance of the fabric.


11 - Air permeability of fabric: “The volume of air passed per second through per unit area of the fabric is called air permeability of fabric”. It is measured in cubic centimeters per second per square centimeter (cm3/second/cm2).
It depends upon the count of yarn, construction of fabric and weight per square unit of the fabric. If the warp and the weft count of two fabrics are identical, then the fabric having more threads per square inch give poor air permeability than lower threads count fabric.
If the threads count per square inch of two fabrics is the same, then the fabric made of coarse count yarn gives poor air permeability.
12 - Abrasion resistance of fabric:  The degree to which a fabric is able to withstand surface wear, rubbing, chafing, and other friction forces. Abrasion resistance allows a fabric surface to resist wear. There are three types of abrasion resistance of the fabric tested.
Flat abrasion resistance: the flat area of the fabric is rubbed or abraded while the fabric is tested for flat abrasion resistance.
Edge abrasion resistance: the edges of the fabric are rubbed or abraded while the fabric is tested for edge abrasion resistance of the fabric.
Flex abrasion resistance: in this condition, the rubbing of the fabric occurs by flexing or bending of the fabric.
The abrasion resistant fabrics are useful for situations in which mechanical wearing and damage can occur. The factors affecting the abrasion resistance are given below:
Type of material used: the type of material majorly affects the abrasion resistance of a fabric. The fabric made of synthetic fibres shows great abrasion resistance in the fabric. The fabrics made of fine and long staple fibres has better abrasion resistance than coarse and short staple fibres. The fabric made of rayon shows poor abrasion resistance.
Degree of twist of the yarn: the twist of the yarn influences the abrasion resistance up to some extent. The yarn having high twist results in the form of improved abrasion resistance in the fabric. If the fabric is made of low twist, it will result in the form of poor abrasion resistance in the fabric.

Count and construction of the fabric: the construction of the fabric also plays important role in the abrasion resistance of the fabric. The fabric having more threads count per square inch results in the form of better abrasion resistance. If the GSM of the fabric increases, it also helps to improve the abrasion resistance of the fabric.

                       THE END 

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