Is wool felt stain-resistant?

フェルトの撥水テスト しょうゆ

I’m now designing a lunch bag. Basic concept is to attach a bag-in-bag made of a natural material which can be machine-washed because wool felt is not suitable for machine-washing. But on my Facebook, some Japanese friends pointed that if the bag-in-bag is made of cotton or linen, spilled soup from a lunch box can get through and felt bag can be stained.

Originally wool is water-repellent thus stain-resistant. That is why I mix soap in water when I make wool felt which helps wool fiber to get wet. Now, how much its water-repellent nature is effective against stain? I have done a quality test.

sample felt and cotton

Samples of wool felt and cotton for the bag-in-bag. I chose wool felt in light gray for better judgement.


First, ketchup was put on the cotton cloth on the wool felt.

I used a glass to push and spread the ketchup. I pushed the glass strongly.

I left them for a while that ketchup was soaked in the cloths.


I took off the cotton cloth … and what? dotted ketchup appeared. Printed area didn’t let ketchup go through.

Before it dried, I started taking off the ketchup by a wet kitchen paper by pressing or knocking.

Ketchup was cleaned!

Then next is soy sauce, Japanese representative sauce. I used a glass to spread and press it this time, too.

Soy sauce got through.


Soy sauce was cleaned by wet kitchen towel!

Moreover, I spilled soy sauce directly on wool felt and pressed by a glass.

ups… it’s not cleaned only with wet kitchen paper

It’s cleaned by kitchen paper with a drop of kitchen detergent!

Then next is ketchup. Again directly on felt.

Ketchup was not cleaned off even with a kitchen detergent. My arm was tired and I gave up.

In addition, I tested if dried ketchup on felt could be cleaned, and it couldn’t.

Bag-in-bag is still needed for a lunch bag, but stain on wool felt could be removed when it’s wet!
Can I go on with this results?



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