Rubber modified styrenic copolymers and their use in disposable card applications

Abstract

A thermoplastic sheet that includes a continuous phase and a dispersed phase, where A) the continuous phase contains a polymer composition resulting from the polymerization of a monomer mixture containing a styrenic monomer and an alkyl (meth)acrylate monomer in the presence of the dispersed phase; and B) the dispersed phase contains one or more block copolymer selected from diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene, partially hydrogenated styrene-isoprene-styrene. The thermoplastic sheet is formed by extruding a thermoplastic composition that is cut to desired dimensions to form thermoplastic items, e.g. identification cards, credit cards, bank cards, key cards, gift cards, phone cards, playing cards, menus, and the like. Indicia and/or printing can be applied to the items to provide for commercial applications. The sheet may be opaque or may be relatively clear to transparent with a Haze value of 0.01% up to 10%.

1 . A thermoplastic sheet comprising a continuous phase and a dispersed phase, wherein: 
 A) the continuous phase comprises a polymer composition resulting from the polymerization of a monomer mixture comprising (i) from about 25 parts by weight to 75 parts by weight of a styrenic monomer and (ii) from about 25 parts by weight to 75 parts by weight of an alkyl(meth)acrylate monomer, wherein the alkyl group is a C 1  to C 12  linear, branched or cyclic alkyl group, in the presence of the dispersed phase; and    B) the dispersed phase comprises from about 2 parts by weight to about 50 parts by weight of one or more block copolymers selected from the group consisting of diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene, partially hydrogenated styrene-isoprene-styrene, for a total of 100 parts by weight of the combination of A) and B),    wherein the thermoplastic sheet has a Haze value of less than 10% and has a melt flow, as measured according to ASTM D-1238 of at least 2.5 g/10 minutes.    
   
   
       2 . The thermoplastic sheet according to  claim 1 , wherein the dispersed phase B) is present as discrete particles dispersed within the continuous phase A).  
   
   
       3 . The thermoplastic sheet according to  claim 2 , wherein the volume average particle size of the dispersed phase B) is from about 0.1 μm to about 2 μm.  
   
   
       4 . (canceled)  
   
   
       5 . The thermoplastic sheet according to  claim 1 , wherein the difference between the refractive index of the continuous phase A) and the dispersed phase B) is not more than 0.01.  
   
   
       6 . The thermoplastic sheet according to  claim 1 , wherein the styrenic monomer is selected from the group consisting of styrene, p-methyl styrene, tertiary butyl styrene, dimethyl styrene, nuclear brominated or chlorinated derivatives thereof and combinations thereof.  
   
   
       7 . The thermoplastic sheet according to  claim 1 , wherein the alkyl(meth)acrylate monomer comprises methylmethacrylate and optionally butyl acrylate.  
   
   
       8 . The thermoplastic sheet according to  claim 1 , wherein the block copolymer has a weight average molecular weight of not less than about 75,000.  
   
   
       9 . The thermoplastic sheet according to  claim 1 , wherein the block copolymer is a linear or radial block copolymer.  
   
   
       10 . The thermoplastic sheet according to  claim 1 , wherein the block copolymer is a triblock styrene-butadiene-styrene or styrene-isoprene-styrene copolymer having a weight average molecular weight of from about 175,000 to about 275,000.  
   
   
       11 . The thermoplastic sheet according to  claim 1 , wherein at least some of the polymers in A) are grafted onto the block copolymer in B).  
   
   
       12 . The thermoplastic sheet according to  claim 1 , further comprising a printed layer over at least a portion of a surface of the thermoplastic sheet.  
   
   
       13 . The thermoplastic sheet according to  claim 12 , wherein the printed layer comprises an ink composition.  
   
   
       14 . The thermoplastic sheet according to  claim 1 , having a thickness of from about 0.05 mm to about 5 mm.  
   
   
       15 . The thermoplastic sheet according to  claim 1 , wherein the sheet is an opaque sheet further comprising pigments or colorants or both.  
   
   
       16 . The thermoplastic sheet according to  claim 1 , wherein the thermoplastic sheet contains indicia thereon.  
   
   
       17 . The thermoplastic sheet according to  claim 1 , wherein the sheet is an opaque sheet further comprising one or more additives selected from the group consisting of lubricants, fillers, light stabilizers, heat stabilizers, surface active agents, and combinations thereof.  
   
   
       18 . The thermoplastic sheet according to  claim 1 , wherein the monomer mixture further comprises a chain transfer agent.  
   
   
       19 . A method of making a thermoplastic item comprising: extruding a thermoplastic composition to form a thermoplastic sheet, wherein the thermoplastic composition comprises a continuous phase and a dispersed phase and has a Haze value of less than 10% and has a melt flow, as measured according to ASTM D-1238 of at least 2.5 g/10 minutes, wherein 
 A) the continuous phase comprises a polymer composition resulting from the polymerization of a monomer mixture comprising (i) from about 25 to 75 parts by weight of a styrenic monomer and (ii) from about 25 to 75 parts by weight of an alkyl(meth)acrylate monomer, wherein the alkyl group is a C 1  to C 12  linear, branched or cyclic alkyl group, in the presence of the dispersed phase; and    B) the dispersed phase comprises from about 2 to about 50 parts by weight of one or more block copolymers selected from the group consisting of diblock and triblock copolymers of styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene, styrene-isoprene-styrene, partially hydrogenated styrene-isoprene-styrene, for a total of 100 parts by weight of the combination of A) and B);    optionally surface treating the extruded sheet;    cutting the sheet to form a smaller sheet of desired dimensions;    printing on a surface of the smaller sheet;    optionally cutting the smaller sheet to desired item dimensions; and    optionally laminating the item.    
   
   
       20 - 38 . (canceled)  
   
   
       39 . A rectangular card made according to the method of  claim 19 .  
   
   
       40 . The card according to  claim 39 , having a first dimensional length of from about 2 cm to about 15 cm, a second dimension of from about 1 cm to about 12 cm and a thickness of from about 0.05 mm to about 5 mm.  
   
   
       41 - 43 . (canceled)