Roofing membrane comprising microspheres

Abstract

A foam suitable for use in roofing systems is provided. Roofing membranes comprising the foam have superior flowing properties at high temperatures without sacrificing low temperature performance. A particular useful roofing membrane comprises an upper surface layer, a reinforcement layer, and optionally a lower self-adhesive layer, wherein expanded microspheres are provided in one or more of said layers in an amount of between 0.01 and 10% based on the total weight of the roofing membrane. Moreover a method of making roofing membranes is provided.

1 . a roofing membrane comprising:
 an upper surface layer   a reinforcement layer, and   optionally a lower self-adhesive layer,   
     wherein expanded microspheres are provided in one or more of said layers in an amount of between 0.01 and 10% based on the total weight of the roofing membrane. 
   
   
       2 . The membrane of  claim 1 , wherein the lower self-adhesive layer is discretely distributed, preferably in form of stribes or patches, over the reinforcement layer. 
   
   
       3 . The membrane of  claims 1  or  2  further, wherein at least the upper surface layer comprises modified bitumen. 
   
   
       4 . The membrane of any one of  claims 1  to  3 , wherein the expanded microspheres are based on polymers obtainable by polymerizing monomers selected from the group consisting of (meth)acrylonitrile, (meth)acrylates, styrenic monomers, vinyl halides, vinylidene halides, vinyl acetate, butadiene, vinylpyridine, and chloroprene. 
   
   
       5 . The membrane of  claim 4 , wherein further comonomeric substances and crosslinking agents are selected from the group consisting of divinylbenzene, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, allyl (meth)acrylate, triacrylformal, and triallyl isocyanurate. 
   
   
       6 . A method of making the roof membrane of  claim 1  comprising:
 providing a reinforcement layer having top and bottom surfaces,   coating a microsphere-containing modified bitumen in a molten state on the top surface of said reinforcement layer,   coating an adhesive layer on the lower surface of said reinforcement layer, and   solidifying the molten embossed layers by cooling the membrane to room temperature.   
   
   
       7 . Microsphere-containing bitumen for use in manufacturing a roofing membrane according to any one of  claims 1  to  5 . 
   
   
       8 . Use of microspheres in the preparation of bitumen for extending the temperature interval in which the bitumen remains flow resistant. 
   
   
       9 . Method for preparing a microsphere-containing bitumen comprising the steps of heating and melting a bitumen product, adding expanded microspheres and cooling the bitumen so as to obtain a foamed bitumen product. 
   
   
       10 . Method for preparing a microsphere-containing bitumen comprising the steps of adding expandable microspheres to a bitumen product, heating until at least a part of the expandable microspheres expand, and cooling the bitumen so as to obtain a foamed bitumen product.