Why are you using double layer packaging on warmer？ by Shuai & Mei Daily Products (Qingdao) Co., Ltd.
Why are you using double layer packaging on warmer？Because the outer layer of warmer is a conventional airtight outer bag, used to cut off air, oxygen is needed to participate in the use, so the inner layer is made of non-woven bag made of microporous breathable film.
The body of the "warm patch" is made of airtight non-woven cloth. Considering that the air cannot penetrate, micro holes are opened on the "warm patch". When using the "warm patch", if the "warm patch" is rubbed, it will cause the microhole blockage and can not heat. Rubbing the "warm patch" does not speed up the heating.
Can paste type "warm patch" uses a special non-woven composite film to prevent oxygen permeation. If you rub the "warm patch", the iron powder in the "warm patch" will be collected on one side and cannot be heated, so it is recommended not to rub the "warm patch".