How To Distinguish Wool Fiber Quality And Quality

First,

Linear density

The linear density of wool fiber has great relationship with physical properties.

In general, the finer the wool is, the more uniform its density is, its strength is higher, its curl is more and its scales are dense. Hikaruzawa Youwa has higher fat and sweat content but shorter length.

Therefore, linear density is an important index to determine the quality of wool.

The small density of wool fibers is beneficial to yarn strength and yarn evenness.

But the fine wool is easier to produce defects when spinning.

The linear density of wool fiber is closely related to the quality and style of wool fabrics.

Commonly used indicators of wool linear density include average diameter, quality number and Tex count.

If the root number distribution of fiber diameter can be obtained, the coefficient of variation of diameter can be used to express the unevenness of wool density.

The diameter of wool fiber varies greatly.

The diameter is about 7 m, and the coarser diameter can reach 240 m.

It is on the same wool that the diameter difference can reach 5~6 m.

The reasons for the difference in density of wool are very complicated, such as breed, age, sex, growth location and feeding conditions of sheep.

On the same sheep, the hair of the shoulders is the most thin, the sides of the body, the neck and the back are the second, the hair of the front neck, buttocks and abdomen is thicker, and the hair of the lower part of the throat, lower leg and tail is thickest.

The number of quality components is an indicator of wool yarn density that has been used in wool industry for a long time.

At present, commercial pactions, the classification of wool textile industry, and the formulation of strip making process all take quality quantity as an important basis.

In the last century, the wool quality was evaluated by sensory method in business.

At the end of last century, according to the spinning equipment and spinning technology level and the quality requirements of wool yarn at the end of last century, the number of British worsted yarns, which could be spun out of various linear density wool, was referred to as the number of quality yarns, so as to indicate the quality of wool.

With the development of science and technology, the improvement of spinning methods, the continuous improvement of the quality requirements of textiles and the progress of research on fiber properties,

The number of quality branches has gradually lost its original meaning.

At present, the quality number of wool represents only the wool fineness index of the average diameter in a certain range.

Two, wool

Length

Wool fibers can be divided into natural length and straightening length due to natural curling.

The straight line distance between the ends of a fiber bundle under natural curl is called natural length, which is usually used to indicate the length of the wool.

Wool fibers are removed from curl, and the length after extension is called the straightening length.

Elongation is used in wool spinning.

The length of wool fiber varies greatly with sheep species, age, sex, hair growth location, feeding conditions, shearing times and seasons.

The length of the fine wool made in China is within the range of 5.5~9cm, the length of semi fine wool can reach 7~15cm, and the coarse wool is 6~40cm.

On the same sheep, the hair of the shoulders, neck and back is longer, and the hair of the head, leg and abdomen is shorter.

When the linear density of wool fibers is the same,

Long and neat wool with short wool content, yarn strength and evenness are better.

The length of wool is also the basis for determining the yarn number and the selection of technological parameters.

Three. Crimp of wool

The crimp of wool fiber is related to the shape of wool, fiber density, elasticity, cohesion and shrinkage.

Crimp also has great influence on yarn quality and fabric style.

The crimp of wool fibers is deep and shallow.

According to the depth of the curl, namely the wave height and the length, namely the wave width difference, the curling shape can be divided into three categories, one is the weak curl.

This kind of curl is characterized by less than half circle of curly arcs, straight and less curled along the length of the fiber.

The crimp of semi fine wool is mostly of this type.

2 for regular curls.

Its characteristic is that the curled waveform is approximately semicircular.

The crimp of fine wool is mostly of this type.

3 is strong curl.

It is characterized by a high amplitude of curl.

There are more curls.

Fine wool sheep belly hair mostly belongs to this type.

Often frizzled wool is used for worsted spinning, spinning elastic and glossy yarns and fabrics.

Strong curly wool is suitable for worsted wool spinning, and it can produce woollen wool with full surface, good handle and elasticity.

The number of crimp marks is the number of crimp; the index of curl depth is the crimp rate; the curling resilience index has curl recovery rate and crimp elastic recovery rate.

Their definitions, formulas and testing methods will be described in the fourth chapter of the curling test of chemical fibers.

The crimp number of fine wool is 6~9 /cm.

Four.

Hygroscopicity

The moisture absorption of wool fibers is expressed by moisture regain.

The hygroscopicity of wool is the strongest among common fibers.

Under general atmospheric conditions, moisture regain is 15%~17%.

Five. Strength and elongation of wool fibers

The tensile strength of wool fibers is the lowest among the commonly used natural fibers, and the breaking length is only 9~18km.

In general, the fineness of wool is smaller, and the smaller the medullary layer, the higher the intensity.

The elongation of wool fibers after stretching is the largest among natural fibers.

The elongation at break can reach 25%~35% and the wet state can reach 25%~50%. After the removal of external force, the elastic recovery ability of elongation is the best among the natural fibers, so the fabric made of wool is not easy to produce wrinkles, and has good wearability.

Six. Chemical stability of wool fibers

Wool fiber is acid resistant and alkali resistant.

The short time action of dilute acid and concentrated acid does little harm to wool, so acid is often used to remove plant impurities such as grass dust in raw wool or in the billet.

Organic acids such as acetic acid and formic acid are wool.

An important dye enhancer.

Alkali can make wool yellows and dissolve.