Lesson 2

MEN'S JEANS 

Description of style 

Regular fit men's jeans in dark blue wash. 

Composition
Made of 100% cotton. 

Cloth construction
The jeans are made from denim which is a durable woven cotton twill originally with an indigo dyed warp and white weft. Material is made from Z-twisted yarns which were dyed before weaving.

Weave structure
It is a warp faced twill which shows the predominance of warp yarns on the face.The lines on the fabric run in Z-direction. The interlacing makes diagonal lines. On the back side of the jeans the twill lines run in the opposite direction. 
The repeat size is three warp and three weft threads. This is the smallest repeat size for a twill weave. 


Cotton 
Cotton is a vegetable fibre and it is composed of cellulose. 

Cotton fibre properties:

Thermal insulation
Cotton fibres are fine and flexible, therefore often made into textiles which relatively low proportion of entrapped air. Denim material is more voluminous which was achieved by specific fabric construction. 

Moisture absorption 
Cotton absorb up to 20% water vapour without feeling wet. However cotton fabrics absorb liquid very rapidly and can contain up to 65% of their own weight without dripping.  One of cotton's disadvantages is that it dries slowly. 

Next to skin comfort 
Cotton fibres are very comfortable next to skin because of their fineness and softness. 

Strength 
Cotton's strength is good. Fibres are stronger wet than dry. Both abrasion and durability are good. 

Electrostatic charge
Cotton fibres always contain moisture which conduct the electrostatic charge away. 

Finesses and handle
Cotton fibres are fine and soft. 

Application
Cotton can be used for many different products. From upper fabrics like shirts and trousers, through accessories (e.g. laces and ribbons), household textiles (e.g.table cloths and bath towels) to technical textiles (workwear and sewing threads).  

Weight of the fabric 
474 g/m2

Testing

Colour fastness to washing (ISO 105-C06, test no. A2S)
We performed a colour fastness to washing test by washing the sample of the jeans in 40° for 30 minutes. After the sample dried we evaluated whether it coloured the other fabric. We did not notice any change on the sample, however we assume it is due to the fact that the jeans used for the assessment were the second-hand ones and most probably washed many times before so they do not colour any more.

Colour fastness to rubbing (ISO 105-X12:2002)

In order to check whether the jeans still can leave stains on other fabrics, we performed the colour fastness to rubbing test with both dry and wet cotton. We realised that even though we were testing an old pair of jeans they still can leave colour when wet, which was a bit surprising comparing with the results with the previous test . We believe it is due to the dark wash of the jeans.                                                                                            

                                                                               Wet: 3                   Dry: 5 


Tearing test (ISO 13937-1/AC:2007)
In order to check the tearing strength of the jeans we performed the tearing test. In the warp direction the sample thorn with 28,21N. In weft direction the sample did not want to tear, showing us that jeans are very strong in the weft direction.