how come the wool on the sheep doesn't shrink in the rain?

Answer 1

rain isn't hot or above 30c.

Wool does not shrink, it felts. And this is simply because of the raised scales of the cuticle layer of the fibre catching on one another. The fibres in a fleece on a sheep are all growing out of the follicles in the same direction, and generally speaking, they all grow at a similar rate. This means that the cuticle scales (which are a bit like the teeth on a saw, but not that pronounced) are all pointed in the same direction. They don't catch on one another. These scales can be seen clearly in electron micrographs.

After the fleece is shorn, the processing stages cause the natural fibre alignment to be completely disrupted. As the fleece is scoured, the "staple" structure is destroyed and the fibres no longer line up "tip to base" as they would in the fleece. They can be in all dimensions and also suffer entangling after scouring and drying, and the purpose of subsequent carding and combing is to remove extraneous matter and disentangle and align the fibres into a parallel arrangement. However the fibres will not necessarily be "tip to base". The scales now can be at 180degrees to one another, and can catch on one another.

When the fibres are spun, they come in close contact with each other, and the interlocking nature of the scales is what helps keep the yarn together (apart from the twist that is inserted). Felting usually occurs in the presence of heat, water and agitation, and this acts as a ratchet, tightening the contact between the fibres in the yarn, and then the yarns in the fabric.

Wool's propensity to felt is because of the scales on the fibre. Other animal fibres have cuticular scales also, but to different degrees. For instance, the scales on human hair are much flatter. I don't know much about dreadlocks, but I imagine this is caused by interrupting the usual parallel arrangement of the hair scales. Fine diameter wools are more likely to felt than broad diameter wools because they have a greater surface area, and hence more scales proportionately.

Shrink-proofing is a chemical treatment of wool, which uses chlorine to "burn" off the scales...this doesn't entirely remove them, but it does lessen their profile, and then the fibres are coated with a resin to smooth the fibre still further. This allows the wool to be machine washed without felting, and the shrinkage of the fabric associated with felting. So that is the story of wool felting in a nutshell."

Answer 2

1.Rain does not fall at high temperatures! If woollen articles are washed in cold water, they do not shrink.
2. If you look carefully at the fleece on the back of a sheep (I used to own two ewes), you will see that below the outside curls the wool is closely matted in a thick layer, very like a mattress. This makes the fleece watertight to rainfall and allows sheep to sleep outside even in sub-zero temperatures without freezing.
But - if there is persistent heavy rainfall and the sheep have no shelter, then their matted fleeces can get waterlogged - the wool doesn't shrink, but the fleece becomes so heavy that the sheep cannot stand up. If it then freezes, the unhappy sheep can get frozen onto the ground!
(Never happened to mine - they had a magnificent shelter and barn, but always slept outside in winter.)

Answer 3

A sheep's wool does not shrink in the rain due to the natural oiliness the name of which i am unsure. This natural oil is extracted but the sheep's wool is being used for knitted garments as its scent is not pleasant

Answer 4

because it's not hot enough, wool is alive (like asking why your hair doesn't shrink in the rain). It may get damaged, but it won't shrink (does wool off a sheep even shrink, i can't think of any sheeps-wool clothes i own that have shrunk...)

Answer 5

The wool on the sheep is kept water repellant due to oils produced by the sheeps skin.

Usually, these oils are removed as part of the processing after shearing so wool we wear does not have this property.


See the following extracted from the web site:


2. Customers should be aware that there are two types of Aran sweaters: "hand loomed" and "hand knitted" – and there are major differences between the two:
- Sheep wool contains natural oil, which makes Aran sweaters water resistant. Wool used in the loom has to be stripped of most of its oil, therefore loomed sweaters are not as waterproof as hand knitted sweaters.
- Stripping the oil out of the wool also makes hand loomed sweaters less dense, heavy and warm.

Answer 6

Because the wool ON the sheep is in it's natural state. It hasn't been twisted and stretched into yarn (spun), and it hasn't been forced into a sweater shape (knitted or crocheted). If it came on the sheep as a sweater, it would shrink on them too.

Answer 7

Perhaps most sheep prefer to use "fabric care" conditioners, which are a must with woollens. They also have the good sense to realise that wool shrinks mostly on cycles at 40 degrees; presumably they only venture out when the rain is at a sensible 30 degrees.

This is also why you never see sheep willingly loading themselves into spin-dryers.

www.on2mobi.com

Answer 8

Shrinkage in woolen fabric is caused by the interlocking of the individual strands of wool in a racheting effect. The water opens up the fibres to expose the cuticles, allowing them to lock up. Wool itself does not shrink dramatically in the way knitted wool does. On the sheep they are generally growing in the same orientation and do not lock up in the way fabrics do.

Answer 9

Because the rain isn't hot enough to alter the fibres of the wool. Your wooly jumper won't shrink either if you go out in the rain but it will if you wash in warm water.

Answer 10

because if you lived in Gods chosen county(or maybe you do)Yorkshire you should know the answer to this question...sheeps wool is full of lanolin which is a grease(which repels water)the wool trade was renowned in the bradford area because the water here is not "hard water"but soft water(no limescale here!)and because of that it takes less soap to wash the wool which kept costs down for manufacturers..your answer is try pouring water on something soaked in oil,,it just will not absorb the water