Floor covering

Abstract

The present invention relates to sheet materials suitable for use in or as a floor covering. The sheet materials comprise a polyalkene resin in intimate admixture with at least one additive comprising a filler, wherein the polyalkene resin has a relatively narrow molecular weight distribution (MWD) and, a small amount of long chain branching and produced by a single site catalysed polymerisation of at least one, linear, branched or cyclic, alkene having from 2 to 20 carbon atoms. The present invention also extends to processes for the production of such sheet materials and floor coverings.

1 . A solid sheet suitable for use as at least one layer of a polymeric floor covering, wherein said solid sheet comprises a polyalkene resin in intimate admixture with at least one additive comprising a filler, wherein said polyalkene resin is a polyalkene resin obtained by a single site catalyzed polymerization of at least one, linear, branched or cyclic alkene having from 2 to 20 carbon atoms.  
     
     
         2 . A solid sheet according to  claim 1 , which polyalkene resin has a molecular weight distribution of less than 3.  
     
     
         3 . A solid sheet according to  claim 1  wherein said polyalkene is one having the following characteristics: 
 a) Melt Index of from 0.1 to 100 dg/minute;  
 b) Density of from 0.86 to 0.97 g/cm 3 ; and  
 c) a small amount of long chain branching which amount is defined as a Dow Rheology Index of from 0.1 to 6.0 measured by comparing the shift to the right, relative to a polymer resin with zero long-chain branching, in a plot of zero shear viscosity against relaxation time.  
 
     
     
         4 . A solid sheet according to  claim 3  wherein said polyalkene resin has a Dow Rheology Index of from 0.4 to 5.5.  
     
     
         5 . A solid sheet according to  claim 1  wherein said polyalkene comprises a copolymer obtainable by copolymerization of at least two alkenes comprising a first, linear or branched, alkene having from 2 to 8 carbon atoms and, at least one comonomer, which comonomer comprises a linear, branched or cyclic, alkene having from 2 to 20 carbon atoms.  
     
     
         6 . A solid sheet according to  claim 5  wherein said first monomer comprises ethylene and said at least one comonomer is selected from butene-1, hexane-1, and norbomene.  
     
     
         7 . A solid sheet according to  claim 5  wherein said comonomer is present in an amount of up to 15 mole percent based on the total amount of said monomer.  
     
     
         8 . A solid sheet according to  claim 1  which includes a polymer, said polymer being obtainable by polymerization of a liquid plasticizer monomer system which is: 
 (i) non-polymerizable under sheet forming conditions used in floor covering sheet material manufacture;  
 (ii) whilst being polymerizable subsequently after forming of said intimate admixture of said polyalkene resin, and said at least one additive, together with said polymerizable plasticizer monomer system into a sheet, so as to produce a sheet material free of liquid plasticizer monomer,  
 at least one of said polymer and said polyalkene resin being cross-linked so that polymer chains of said polymer and polymer chains of said polyalkene resin together form an at least semi-interpenetrating network of polymer chains.  
 
     
     
         9 . A solid sheet according to  claim 8  wherein said plasticizer monomer comprises a linear, branched or cyclic alkene having at least 10 carbon atoms and a polymerizable terminal function group.  
     
     
         10 . A solid sheet material according to  claim 1 , which solid sheet is itself suitable for use directly as a polymeric floor covering.  
     
     
         11 . A solid sheet according to  claim 1  which is free of liquid plasticizer.  
     
     
         12 . A process for the production of a solid sheet suitable for use as at least one layer of a polymeric floor covering, said process comprising the steps of: 
 providing a polyalkene resin obtained by a single site catalyzed polymerization of at least one, linear, branched or cyclic, alkene having from 2 to 20 carbon atoms and at least one additive comprising an inorganic filler;    bringing said polyalkene resin into intimate admixture with said at least one additive in a high shear mixer for a period of at least 10 minutes at an elevated temperature of at least 75° C. for melting the polyalkenes and sufficient to bring the mixture into a fluid state without degradation of the mixture;    forming the fluid mixture into a sheet form; and    allowing said sheet to cool and solidify.    
     
     
         13 . A process according to  claim 12  which includes the further step of incorporating into the mixture a sheet forming processing aid.  
     
     
         14 . A process according to  claim 12  wherein the sheet forming process comprises spread coating.  
     
     
         15 . A process according to  claim 14  wherein a liquid plasticizer is used as a spread coating aid in said spread coating step.  
     
     
         16 . A process according to  claim 15  wherein a liquid paraffin is used as a spread coating aid in said spread coating step.  
     
     
         17 . A process according to  claim 13  wherein the step of incorporating into the mixture a sheet formation processing aid comprises the further step of incorporating a polymerizable liquid plasticizer monomer system which is: 
 (i) non-polymerizable under sheet forming conditions used in floor covering sheet material manufacture, while  
 (ii) being polymerizable subsequently so as to produce a polymer material free of liquid plasticizer monomer.  
 
     
     
         18 . A process according to  claim 17  which process includes the further step of treating the sheet form material so as to induce polymerization of said liquid plasticizer monomer system thereby to produce a sheet material free of liquid plasticizer.  
     
     
         19 . A process according to  claim 18  wherein said sheet forming step is carried out at from 70 to 120° C. and said polymerization step is carried out at from 150 to 250° C.  
     
     
         20 . A process according to  claim 12  wherein the sheet forming process step comprises the further step of rolling said fluid mixture on a calendar.