Patent ID: 8686072
Filing Date: 2014-04-01
Classification: C08K,C08L

Abstract:
1. A thermoplastic polyester composition comprising, based on the weight of the composition, a chlorine- and bromine-free combination of: (a) from 40 to 60 wt % of a modified poly(1,4-butylene terephthalate) that (1) is derived from consisting of a poly(ethylene terephthalate) copolymer comprising a mixture of ethylene glycol groups, diethylene glycol groups, terephthalic acid groups, and isophthalic acid groups, and 1,4-butanediol, and (2) comprises a mixture of 1,4-butanediol groups, ethylene groups, diethylene glycol groups, terephthalic acid groups, and isophthalic acid groups; (b) from 25 to 35 wt % of a glass fiber filler; (c) from 2 to 8 wt % of a flame retardant synergist selected from the group consisting of melamine polyphosphate, melamine cyanurate, melamine pyrophosphate, melamine phosphate, and combinations thereof; (d) from more than 10 to 15 wt % of a phosphorus flame retardant comprising: a phosphinate of formula (I) (e) at least 1% to less than 5 weight % of impact modifier component comprising a combination of (i) a poly(ether-ester) elastomer and (ii) a core-shell (meth)acrylate impact modifier; wherein the poly(ether-ester) elastomer comprises long-chain ester units of formula (III): and short-chain ester units having units of formula (IV): wherein R′ is a divalent aromatic radical remaining after removal of carboxyl groups from terephthalic acid, isophthalic acid, or a combination of terephthalic acid and isophthalic acid; G is a divalent polyalkylene oxide radical remaining after removal of terminal hydroxyl groups from a poly(alkylene oxide)glycol having a number-average molecular weight of 100 to 2500; and D is a divalent alkylene radical remaining after removal of hydroxyl groups from aliphatic diols having a molecular weight from 62 to 286; and wherein the core-shell meth(acrylate) impact modifier has a crosslinked poly(butyl acrylate) core with a grafted poly(methyl methacrylate) shell; (f) from more than 0 to 5 wt % poly(tetrafluoroethylene) encapsulated by a styrene-acrylonitrile copolymer; and (g) from more than 0 wt % to 2 wt % of a stabilizer; wherein the thermoplastic polyester composition contains less than 3 wt % of a polyetherimide; and wherein an article molded from the composition exhibits (a) a flexural modulus that is more than 9800 MPa to less than or equal to 20,000 MPa, measured on 3.2 mm thick bars in accordance with ASTM D 790; (b) a flexural stress that is more than 150 MPa to less than or equal to 190 MPa, measured on 3.2 mm thick bars in accordance with ASTM D 790; (c) an unnotched Izod impact strength that is more than 470 Joules/meter to less than or equal to 700 Joules/meter, measured on 75 mm×12.5 mm×3.2 mm bars at 23 °C. in accordance with ASTM D 256; and (d) a V0 rating, measured on 0.8 m thick flame bars after conditioning for 48 hours at 23 °C., and 0.8 mm thick flame bars after conditioning for 168 hours at 70 °C., in accordance with UL 94.