Thanks for the question.

You are correct that “tack” is a binder that enables straw to form matts.  It also prevents the straw from washing and/or blowing away.  I believe that the product sold by Lowe’s goes under the name of EZ Straw.  The tack used in this product is a bonding agent that gives the straw a tackiness and holds it together protecting the grass seed from wind and heavy wash out. Tackifier feeds the soil as it decomposes.  It is therefore biodegradable  It is safe for use around children and pets.  It makes an excellent garden mulch though it may take a little bit of work to fit it around plants if they are irregularly planted in the garden.  I have heard many good reviews of its use by other gardeners.

Good Luck