Flame-resistant polycarbonates

Claim 2

Molding compositions consisting essentially of aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000 and about 0.5 to 7% by weight of sulphur, relative to the total weight of polycarbonate and sulphur.

Claim 3

Molding compositions according to claim 1, characterized in that they contain aromatic polycarbonates based on at least one of the following bisphenols: 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl-sulphide, 2,2-bis-(4-hydroxyphenyl)-propane, 2,4-bis-(4-hydroxhphenyl)-2-methylbutane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane, α,α-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, 2,2-bis-(3-methyl-4-hydroxyphenyl)-propane, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-methane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-sulphone, 2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, 1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane, α,α'-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane and/or 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.

Claim 4

Molding compositions according to claim 1, characterized in that they contain copolycarbonates based on 2,2-bis-(4-hydroxyphenyl)-propane and one of the bisphenols 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane or 1,1-bis-(4-hydroxyphenyl)-cyclohexane.

Claim 5

Molding compositions according to claim 1, characterized in that they contain aromatic polycarbonates based on 2,2-bis-(4-hydroxyphenyl)-propane.

Claim 6

A molding composition comprising a blend of aromatic polycarbonates having molecular weights, M w , of about 10,000 to about 200,000 with about 0.5 to 7 wt. %, based on the total weight of the blend, of a flame retardant consisting of sulphur.

Claim 7

A molding composition comprising a blend of aromatic polycarbonates having molecular weights, M w , of about 10,000 to about 200,000 with about 0.5 to 7 wt. %, based on the total weight of the blend, of a flame retardant consisting of sulphur.

Claim 8

The molding composition of claim 5 wherein the polycarbonates have molecular weights M w of about 20,000 to 80,000 and the blend contains about 0.5 to 7 wt.% sulphur based on the total weight of the blend.

Claim 9

The molding composition of claim 5 wherein the blend also contains a small proportion of a low molecular weight polycarbonate having average degrees of polymerization of about 2 to 20.

Claim 10

The molding composition of claim 7 wherein the low molecular weight polycarbonates are based on 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.

Claim 11

A process for improving the flame resistance of polycarbonate molding compositions having molecular weights, M w , of about 10,000 to 200,000 comprising physically incorporating into the composition about 0.5 to 7 wt. %, based on the total weight of the composition, of a flame retardant consisting of sulphur.

Claim 12

A process for improving the flame resistance of polycarbonate molding compositions having molecular weights, M w , of about 10,000 to 200,000 comprising physically incorporating into the composition about 0.5 to 7 wt. %, based on the total weight of the composition, of a flame retardant consisting of sulphur.

Claim 13

The process of claim 9 wherein the sulphur is dissolved in a melt of the polycarbonate.

Claim 14

The process of claim 9 wherein the sulphur is mechanically mixed with polycarbonate granules or powders and the mixture is processed at temperatures in excess of about 160° C to produce a homogeneous blend.

Claim 15

The product of the process of claim 9.

Claim 16

A process for improving the flame resistance of polycarbonate molding compositions consisting essentially of physically incorporating about 0.5 to 7 wt % of sulphur, based on the total weight of the composition, into the composition.

Claim 17

A process for improving the flame resistance of polycarbonate molding compositions consisting essentially of physically incorporating about 0.5 to 7 wt % of sulphur, based on the total weight of the composition, into the composition.

Claim 18

Molding compositions consisting essentially of aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000, about 0.5 to 7% by weight of sulphur, relative to the total weight of polycarbonate and sulphur, and up to 30% by weight

Claim 19

Molding compositions consisting essentially of aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000, about 0.5 to 7% by weight of sulphur, relative to the total weight of polycarbonate and sulphur, and up to 30% by weight

Claim 20

Molding compositions based on aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000 containing about 0.5 to 7% by weight of sulphur, based on the total weight of polycarbonate and sulphur, and no additional additives having a substantial effect on the flame retardancy of the composition.

Claim 21

Molding compositions based on aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000 containing about 0.5 to 7% by weight of sulphur, based on the total weight of polycarbonate and sulphur, and no additional additives having a substantial effect on the flame retardancy of the composition.

Claim 22

Molding compositions based on aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000 containing about 0.5 to 7% by weight of sulphur, based on the total weight of polycarbonate and sulphur, up to 30% by weight of glass fibers relative to the total mixture and no additional additives having a substantial effect on the flame retardancy of the composition.

Claim 23

Molding compositions based on aromatic polycarbonates having molecular weights M w of about 20,000 to 80,000 containing about 0.5 to 7% by weight of sulphur, based on the total weight of polycarbonate and sulphur, up to 30% by weight of glass fibers relative to the total mixture and no additional additives having a substantial effect on the flame retardancy of the composition.

Claim 24

A molding composition comprising a homogeneous blend of aromatic polycarbonates having molecular weights, M w , of about 20,000 to 80,000 based upon bisphenols selected from the group consisting of 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane and 2,2-bis-(4-hydroxyphenyl)-propane and about 0.5 to 7 wt. %, based on the total weight of the composition, of a flame retardant consisting of sulphur.

Claim 25

A molding composition comprising a homogeneous blend of aromatic polycarbonates having molecular weights, M w , of about 20,000 to 80,000 based upon bisphenols selected from the group consisting of 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane and 2,2-bis-(4-hydroxyphenyl)-propane and about 0.5 to 7 wt. %, based on the total weight of the composition, of a flame retardant consisting of sulphur.