Lesson 3

UNDERWEAR

Description of style

It is a top with elastic adjustable straps and a butterfly detail on one strap. There are beats on the breast part as a decoration. 

Composition

95% cotton, 5% elastane

Cloth construction 

The main body

The main body of the top is weft knitted which means the yarns are fed crosswise to the length of the fabric. 
It is a 1x1 rib fabric. Rib fabrics are made on two needle beds with the needles in a staggered formation. Both sides of the fabric show only face loops. It is a very extensible fabric in the width. 
This knit structure fabric is usually used for pullovers, waistcoats, underwear and socks. 

Advantages of the knit structure: 
- soft
- elegant drape
- body-hugging fit
- extensible in the width.

Disadvantages of the knit structure: 
- rib knits with no elastane may stretch out over time
- requires more care in laundering to keep the piling down.

Material is made from Z-twisted yarns which were dyed before knitting.

The straps

The straps of the top are woven by using the weft insertion shuttle. The weft yarn is wound on a small bobbin which fits inside the shuttle. The shuttle is then repeatedly driven across the loom going over a smooth surface in front of the reed and then driven back again trailing the weft behind it. 

Cotton

Properties of the cotton fibres you can find in our previous posts about jeans. 

Elastane 

Elastane is a synthetic fibre which is manufactured from at least 85 % of a segmented polyurethane. It has a very high elastic recovery. An elastomeric yarn can stretch by up to 500 % and recover its original length after unloading. Elastane is made only as a filament yarns. The filaments can be very fine, are resistant to light and oxidation, and will withstand domestic laundering. They are used where ever high elasticity is required. Fabrics with small amount of elastane (2-5%) are used for gentle shape-holding elasticity. Covered yarns are used in e.g. cotton or wool outerwear, usually at the level of 2-5%. They are unseen within the fabric, never coming into contact with the body, providing invisible elasticity and wrinkle resistance.        

Weight of the fabric

262 g/m2 or 9.24 oz

Testing

Colour fastness to washing DS/EN ISO 105-C06:2010

We decided to run the test on the top to check it's colour fastness to washing. Because the top 
was already washed once we decided not to follow the care label instructions and test it in higher temperature with a bleaching agent. We washed the sample in 60° for 30 minutes. After that we used the ISO 105-A03  light grey scale to asses the sample. 

Shrinkage test DS/EN ISO 6330:2012

When washing in the machine we used the 2A washing procedure with 2+/- 0,1. With a load of 5 kg. 

We washed and tumble dried the top, to find out if there was a dimensional change. After washing and drying we assessed the top again using DS/EN ISO 5077:2008.

In addition to shrinkage test, we realised after washing that the side seams of the top twisted. 

Pilling resistance test DS/EN ISO 12945-2:2000

We used the Martindale machine to check the pilling of the top. Even though the machine is usually used to test woven fabrics we decided to use it for our test because we did't have enough material to use the pilling box. After each amount of turns we assessed the sample giving it a grade from 1-5, where 5 is the best. 

Pilling resistance test

Pilling resistance test is one type of physical testing carried in order to acquire information regarding textile performance. It is a measurement of the number of pills that are formed during a defined period of surface rubbing. Pilling is a fabric surface fault characterized by little pills of entangled fibres clinging to the surface. Pills are formed during wearing or washing by the entanglement of the loose fibres, which protrude from fabric surface. The pilling of textile fabrics is a very complex property, because it is affected by many factors, which may include type of fibre or blends, fibre dimensions, yarn and fabric construction, fabric finishing treatments and refurbishing method. Pills vary appreciably in size and appearance and depend on the presence of lint and degree of colour contrast. The development of pills may be accompanied by other surface phenomena such as loss of cover, colour change, or the development of fuzz.
There are two types of pilling resistance tests:

a) Pilling Resistance (Pilling Box Method) (BS EN ISO 12945-1)

b) Pilling Resistance (Modified Martindale Method) (BS EN ISO 12945-2)

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.