MULTILAYER SHEET AND METHODS OF MAKING AND ARTICLES COMPRISING THE MULTILAYER SHEET
In some embodiments, a multilayer sheet comprises: a first cap layer formed from a first cap composition comprising polycarbonate and potassium perfluorobutane sulfonate; a second cap layer formed from a second cap composition comprising polycarbonate and potassium perfluorobutane sulfonate; and a core layer formed from a core composition comprising polycarbonate and without potassium perfluorobutane sulfonate. The core layer is disposed between the first cap layer and the second cap layer.
1 . A multilayer sheet, comprising:
a first cap layer formed from a first cap composition comprising polycarbonate and potassium perfluorobutane sulfonate;
a second cap layer formed from a second cap composition comprising polycarbonate and potassium perfluorobutane sulfonate; and
a core layer formed from a core composition comprising polycarbonate and without potassium perfluorobutane sulfonate, wherein the core layer is disposed between the first cap layer and the second cap layer.
2 . The multilayer sheet of claim 1 , wherein the core composition and the first and second cap composition are selected from the group consisting of linear polycarbonate, copolymers of polycarbonate, branched polycarbonate, end-capped polycarbonate, and combinations comprising at least one of the foregoing.
3 . The multilayer sheet of claim 2 , wherein the first cap composition and the second cap composition comprise a branched, nitrile endcapped polycarbonate comprising greater than or equal to 3 mole % branching agent.
4 . The multilayer sheet of claim 3 , wherein the branching agent comprises trimellitic trichloride and/or 1,1,1-tris(4-hydroxyphenyl)ethane.
5 . The multilayer sheet of claim 2 ,
wherein the first cap composition and the second cap composition comprise
0.03 wt % to 1 wt % potassium perfluorobutane sulfonate,
25 wt % to 75 wt % branched, nitrile endcapped polycarbonate comprising greater than or equal to 3 mole % branching agent, wherein the branching agent comprises trimellitic trichloride and/or 1,1,1-tris(4-hydroxyphenyl)ethane; and
25 wt % to 75 wt % linear polycarbonate;
wherein the weight percent is based upon the total weight of the cap composition and the weight percent amount totals 100%; and
wherein the core composition comprises branched polycarbonate.
6 . The multilayer sheet of claim 5 ,
wherein the core composition branched polycarbonate comprises branched, nitrile endcapped polycarbonate comprising greater than or equal to 3 mole % branching agent, and is present in an amount of 25 wt % to 75 wt %; 25 wt % to 75 wt % linear polycarbonate;
0.01 wt % to 1.0 wt % potassium diphenylsulfone sulfonate;
0.01 wt % to 0.1 wt % octaphenyl cyclotetra siloxane; and
0.03 wt % to 1 wt % potassium perfluorobutane sulfonate;
wherein the weight percent is based upon the total weight of the core composition and the weight percent amount totals 100%.
7 . The multilayer sheet of claim 5 , wherein the first cap composition and the second cap composition are bromine and chlorine free.
8 . The multilayer sheet of claim 1 , wherein the amount of potassium perfluorobutane sulfonate in the multilayer sheet is less than 0.01 wt % based upon a total weight of the multilayer sheet.
9 . The multilayer sheet of claim 1 , wherein the core layer flame retardant additive comprises potassium diphenyl sulfone-3-sulfonate.
10 . The multilayer sheet of claim 1 , wherein the first cap composition contains greater than or equal to 0.05 wt % potassium perfluorobutane sulfonate, based upon a total weight of the first cap composition and the second cap composition contains greater than or equal to 0.05 wt % potassium perfluorobutane sulfonate, based upon a total weight of the second cap composition.
11 . The multilayer sheet of claim 1 , wherein the multilayer sheet has a UL94 V0 rating at a thickness of 1.8 mm.
12 . The multilayer sheet of claim 11 , wherein the multilayer sheet has a haze value of less than or equal to 1.5% as measured by ASTM D1003-00, Procedure A.
13 . The multilayer sheet of claim 1 , wherein the cap layer comprises a thickness of less than or equal to 200 micrometers.
14 . The multilayer sheet of claim 1 , wherein the core layer is co-extruded with the first cap layer and the second cap layer.
15 . The multilayer sheet of claim 1 , wherein the core layer has a thickness of less than or equal to 2 mm.
16 . An article comprising the multilayer sheet of claim 1 .
17 . A method of making a multilayer sheet, comprising:
forming a core layer formed from a core composition comprising polycarbonate;
forming a first cap layer formed from a first cap composition comprising polycarbonate and potassium perfluorobutane sulfonate wherein the first cap layer is co-extruded onto a surface of the core layer; and
forming a second cap layer formed from a second cap composition comprising polycarbonate and potassium perfluorbutane sulfonate wherein the second cap layer is co-extruded onto a surface of the core layer opposite the surface co-extruded with the first cap layer.
18 . The method of claim 17 , wherein the multilayer sheet has a UL94 V0 rating at a thickness of 1.8 millimeters.
19 . The method of claim 17 , wherein the multilayer sheet has a haze value of less than or equal to 1.5% as measured by ASTM D1003-00, Procedure A.
20 . The method of any of claim 17 , further comprising coextruding the core layer, first cap layer, and second cap layer.