Shalom, I ordered a hat in the shop (but still have not bought it). The hat is made of two kinds of materials: viscose-35%, polyester-65%. My question is: (considering I will buy it) wearing such a hat – wouldn’t it be a violation of a Torah prohibition (in Leviticus 19:19) to wear a cloth made of the two different kinds of materials? To my opinion – not, since both viscose and polyester can be considered artificial sorts of fibre (since they are made of cellulose and a synthetic polymer respectively) and, therefore, can not be considered a natural fibre (to which the mentioned Torah prohibition, in my opinion, refers). Thanks.
Shatnez is only if the item contains wool and linen in it. Being that the two materials are either not wool or linen, it is very possible that it is alright. However many times there are problems because of the stuffing inside the hats or the stitching of the hat. This would need the experience of someone that is an expert in shatnez. Please refer to the following e-mail addresses email@example.com for a better answer to your specific hat.