Modified weatherable polyester molding composition
View Patent ↗A composition formed from (a) a polyester and polycarbonate blend; (b) an organopolysiloxane-polycarbonate block copolymer; (c) an acrylic core shell impact modifier; (d) titanium dioxide and (e) a flame retarding amount of a halogenated flame retardant has properties useful as a weatherable molding composition. It can suitably be used in articles such as encloses for electronic equipment such as communication devices.
1. A composition comprising (a) a polyester and polycarbonate blend; (b) an organopolysiloxane-polycarbonate block copolymer; (c) an acrylic core shell impact modifier; (d) titanium dioxide and (e) a flame retarding amount of a halogenated flame retardant.
2. A composition according to claim 1 wherein the acrylic core shell impact modifier has a particle size of from 300 to 800 nm.
3. A composition according to claim 1 wherein said acrylic core shell impact modifier comprises a multi-phase composite interpolymer comprising about 25 to 95 weight percent of a first acrylic elastomeric phase polymerized from a monomer system comprising about 75 to 99.8% by weight C 1 to C 14 alkyl acrylate, 0.1 to 5% by weight cross linking member, 0.1 to 5% by weight graft linking monomer, said cross linking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups and about 75 to 5 weight percent of a final, rigid thermoplastic acrylic or methacrylic phase polymerized in the presence of said elastomer.
4. A composition according to claim 1 wherein said acrylic core shell impact modifier comprises a multi-phase composite interpolymer comprising about 25 to 95 weight percent of a first acrylic elastomeric phase polymerized from a monomer system comprising about 75 to 99.8% by weight C 1 to C 14 alkyl acrylate, 0.1 to 5% by weight cross linking member, 0.1 to 5% by weight graft linking monomer, said cross linking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups and about 75 to 5 weight percent of a final, rigid thermoplastic acrylic or methacrylic phase polymerized in the presence of said elastomer.
5. A composition according to claim 1 wherein said acrylic core shell impact modifier comprises a multi-phase composite interpolymer comprising about 25 to 95 weight percent of a first elastomeric phase polymerized from a monomer system comprising about 5-50% polydimethylsiloxane, 30 to 99.8% by weight C 1 to C 14 alkyl acrylate, 0.1 to 5% by weight cross linking member, 0.1 to 5% by weight graft linking monomer, said cross linking monomer being a polyethylenically unsaturated monomer having a plurality of addition polymerizable reactive groups and about 75 to 5 weight percent of a final, rigid thermoplastic acrylic or methacrylic phase polymerized in the presence of said elastomer.
6. A composition according to claim 1 wherein said organopolysiloxane-polycarbonate copolymer comprises organopolysiloxane blocks having repeating units of the general formula:
wherein R′ is a member selected from the class of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals; E is independently selected from the group consisting of hydrogen, lower alkyl, alkoxy radicals, aryl, and alkylaryl, halogen radicals and mixtures thereof, and R″ is a divalent hydrocarbon radical, and n is from about 10 to about 120.
7. A composition according to claim 2 wherein said organopolysiloxane-polycarbonate copolymer comprises polycarbonate blocks having repeating units of the general formulae:
wherein E is independently selected from the group consisting of hydrogen, lower alkyl, alkoxy radicals, aryl, and alkylaryl, halogen radicals and mixtures thereof, and D is a divalent hydrocarbon radical containing from 1-15 carbon atoms; —S—, —SO—, —S(O) 2 ; and —O—.
8. A composition according to claim 3 wherein said organopolysiloxane-polycarbonate copolymer comprises polycarbonate blocks having repeating units of the general formulae:
wherein E is independently selected from the group consisting of hydrogen, lower alkyl, alkoxy radicals, aryl, and alkylaryl, halogen radicals and mixtures thereof, and R is selected from the group consisting of hydrogen, cycloaliphatic, aryl, monovalent hydrocarbon radicals, aryl or alkyaryl.
9. A composition according to claim 1 wherein said organopolysiloxane-polycarbonate copolymer comprises organopolysiloxane blocks having repeating units of the general formulae:
R′ is a member selected from the class of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals; E is a member independently selected from the class of hydrogen, lower alkyl, alkoxy radicals, aryl, and alkylaryl, halogen radicals and mixtures thereof; R″ is a divalent hydrocarbon radical; n is from about 10 to about 120; R is a member selected from the class of hydrogen, cycloaliphatic, aryl, monovalent hydrocarbon radicals and alkylaryl.
10. A composition according to claim 5 wherein E is independently selected from the group consisting of hydrogen, alkyl of 1 to 6 carbon atoms, and halogen.
11. A composition according to claim 1 wherein said polyester is derived from an aliphatic diol and an aromatic dicarboxylic acid having repeating units of the following general formula:
wherein each A is independently a divalent aliphatic, salicylic or aromatic hydrocarbon or polyoxyalkylene radical, or mixtures thereof and each B is independently a divalent aliphatic, salicylic or aromatic radical, or mixtures thereof.
12. A composition according to claim 1 wherein comprises an aromatic polycarbonate resin comprises one or more resins selected from linear aromatic polycarbonate resins, branched aromatic polycarbonate resins and poly(ester-carbonate) resins.
13. A composition according to claim 1 wherein said polycarbonate comprises a linear aromatic polycarbonate resin.
14. A composition according to claim 1 wherein said polycarbonate comprises a poly (ester carbonate).
15. A composition according to claim 1 , comprising 10-60% polycarbonate, 25 to 50% polyester, 5 to 15% acrylic core shell impact modifier, 5-50% organopolysiloxane-polycarbonate block copolymer, 5-20% flame retardant and 0.1 to 10% titanium dioxide each based on 100 parts by weight of the composition.
16. A composition according to claim 1 wherein the resin comprises from 15 to 55 parts by weight, of the polycarbonate resin; from 25 to 55 parts by weight of the polyester resin; from 20 to 35 parts by weight of the organopolysiloxane-polycarbonate block copolymer; and from 5 to 15 parts by weight of the acrylic impact modifier, and 0.1 to 10% titanium dioxide each based on 100 parts by weight of the composition.
17. A composition according to claim 1 wherein said flame retardant is a halogenated epoxy, poly (haloarylmethacrylate), halogenated polystyrene or a poly (haloarylacrylate) flame retardant.
18. A composition according to claim 1 wherein said flame retardant is a polybromobenzylacrylate flame retardant.
19. A composition according to claim 1 , comprising 25-60% polycarbonate, 25 to 50% polyester, 5 to 15% acrylic core shell impact modifier, 5-20% organopolysiloxane-polycarbonate block copolymer, 5-20% flame retardant and 0.1 to 10% titanium dioxide each based on 100 parts by weight of the composition.
20. An article molded from the composition of claim 1 .
21. A molded article according to claim 20 comprising an injection molded article.
22. A molded article according to claim 20 , comprising an enclosure for an electrical communication device.
23. A molded article according to claim 20 comprising a cable connector, telephone, computer, video, and network interface devices for residential, commercial or industrial use.