Need help please! Would like to know the material used
 

Hi....the pics are of a cover for a heating pad that a friend who rescues cats and kittens asked me to make. It feels like the cover is polar fleece but was wondering what the mesh-like material could be inside. The heating pad would go into the microwave for a minute. Can polar fleece go into the microwave? Just wondering what materials I could use to try to recreate it. Thanks so much!

The inside looks like an interfacing. It is probably used to help the fleece hold it’s shape

Welcome to the B from SE Michigan! When you buy your fleece check the end of the bolt to see if it is microwave safe. Some are some aren't. Those fleeces made for baby pj's. are usually safe to use.

Oh, I just realized the polar fleece won't be going into the microwave so I would only need to know what mesh-type material you would use please. Thanks so much.

The mesh material is some type of interfacing. Probably used to keep the fleece from stretching out too much. Possibly an iron on. Take it along to the fabric store. They should know exactly what type of interfacing it is.

Fusible interfacing can be applied using a damp pressing cloth, steam & a moderate temperature.

It looks like the nonwoven polypropylene fabric that is used to make reusable shopping bags. Quilting cotton would hold up better and it would be a good project to use up scraps.

cjsews is right. You might find the lining fabric placed among facings/fusibles, but any fabric will do since the fleece is not going into the microwave.

I make warm up rice bags using polar fleece. Many are several years old and go in the microwave. I neve do more than 30 secs to 45 secs. get warm and moist.
I have given as gifts and sold plenty at craft fairs. Always with directions. Have not had any issues.
Nice that you want to help a charity.

polar fleece to me is the plush thicker fleece. i used to make blankets out of that with double polar fleece tied all around. fleece shrinks so wash it well and read label and test a bit of it too. that inside doesn't look like it lasted very well so I'd not want to duplicate it. good old cotton should work for the inside. have fun.