Ferro Corporation

Albemarle Corporation

James C Gill

James L Dever

A brominated polystyrene product made by the process comprising pretreating a solution of a polystyrene reactant comprising from about five to about 20 percent by weight of the polystyrene reactant, in a halogenated hydrocarbon solvent with at least about 0.1 percent by weight of an additive to suppress halogenation of the polystyrene backbone, prior to brominating the polystyrene in the presence of a catalyst; subsequently adding a metal halide bromination catalyst to the solution, capable of effecting bromination of the ring without causing crosslinking of the polystyrene; adding to the solution from about 1 to about 3.4 moles of a brominating agent, per mole of polystyrene repeating units; reacting the polystyrene with the brominating agent at a temperature of from about &minus;20&deg; C. to about 50&deg; C., and isolating the brominated polystyrene. A brominated polystyrene is provided having a backbone halogen content of less than about 750 ppm and a &Dgr;E color of from about 5 go about 19.

Brominated polystyrene having improved thermal stability and color and process for the preparation thereof

A flame retardant additive comprising a brominated copolymer, wherein the copolymer is a copolymer of styrene and an acrylate or methacrylate monomer defined by the formula ##STR1## where R.sub.1 is a methyl group or hydrogen and R.sub.2 is an organic group having between one and about 18 carbon atoms. A method for imparting flame retardancy to a thermoplastic material without deleteriously impacting the color thereof comprises the step of adding a brominated copolymer to the thermoplastic material, wherein the copolymer is a copolymer of styrene and an acrylate or methacrylate monomer defined by the formula ##STR2## where R.sub.1 is a methyl group or hydrogen and R.sub.2 is an organic group having between one and about 18 carbon atoms. The present invention also includes a brominated copolymer of styrene and an acrylate or methacrylate monomer.

Brominated copolymer flame retardant additives having improved color

The present invention provides a method of producing a flame-retardant polymer comprising mixing one or more polymeric base resins with a source of brominated syndiotactic polystyrene that displays a noncrystalline order and is produced by a process comprising brominating syndiotactic polystyrene in an inert reaction medium that is incapable of dissolving to any appreciable degree syndiotactic polystyrene at ambient temperature and pressure. The produced brominated syndiotactic polystyrene has a melting temperature in excess of about 325.degree. C.

Brominated syndiotactic polystyrene and the use thereof

The present invention provides a new flame-retardant additive comprising brominated syndiotactic polystyrene. The additive has a melting temperature in excess of about 325.degree. C. and it displays a noncrystalline order. The additive also has less than 1500 ppm halogen located on the backbone of the syndiotactic polystyrene as measured in HBr equivalents. The additive provides for better color and improved thermal stability as compared to the use of conventional brominated polystyrene.

In a process for the suppression of backbone halogenation during the bromination of polystyrenes comprising the step of pretreating a solution of a polystyrene reactant comprising from about five to about 20 percent by weight of a polystyrene reactant, in a halogenated hydrocarbon solvent with at least about 0.1 percent by weight of an additive to suppress halogenation of the polystyrene backbone prior to brominating the polystyrene in the presence of a catalyst; adding a metal halide bromination catalyst to the solution, capable of effecting bromination of the ring without causing crosslinking of the polystyrene; adding to the solution from about 1 to about 3.4 moles of a brominating agent, per mole of polystyrene repeating units; reacting the polystyrene reactant with the brominating agent at a reaction temperature of from about -20.degree. C. to about 50.degree. C., and isolating the brominated polystyrene. A brominated polystyrene is also provided having a backbone halogen content of less than about 750 ppm and, a .DELTA.E color as low as about 5.

Brominated polystyrene having improved thermal stability and color and

In a process for the preparation of brominated polystyrene, as an additive for polymer matrices to impart flame retardancy, including preparing a solution of a polystyrene reactant comprising from about five to about 20 percent by weight of a polystyrene reactant, in a halogenated hydrocarbon solvent; adding a Lewis acid bromination catalyst to form a solution; adding to the solution from about 1 to about 3.3 moles of a brominating agent, per mole of polystyrene repeating units, and reacting the polystyrene reactant with the brominating agent at a reaction temperature of from about -20.degree. C. to about 50.degree. C.; wherein the improvement comprises controlling the color characteristics of the resultant brominated polystyrene by selecting a polystyrene reactant having a weight average molecular weight of from about 500 to about 1,500,000; selecting a catalytically effective amount of the catalyst on the basis of having a strength sufficient to effect at least monobromination of the polystyrene without inducing alkylation of the polystyrene by the halogenated hydrocarbon solvent; selecting a brominating agent from the group consisting of bromine chloride and bromine; operating at the lowest possible temperature within the range, consistent with the brominating agent and the catalyst selected; and isolating the brominated polystyrene, wherein the color properties of the resultant brominated product are improved by selection and consideration of reaction time and temperature, catalyst, brominating agent and method of product isolation.

Process for the preparation of brominated polystyrene having improved

Brominated polysytrene having improved thermal stability and color and

The present invention provides a new method for making an improved flame-retardant additive comprising a brominated syndiotactic styrenic polymer. The method includes the steps of providing a source of syndiotactic styrenic polymer; providing a source of inert reaction medium that is not capable of dissolving to any appreciable degree the syndiotactic styrenic polymer at ambient temperature and pressure; providing a source of brominating agent; providing a source of Lewis acid catalyst; mixing the syndiotactic styrenic polymer with the inert reaction medium and the Lewis acid catalyst; and reacting the syndiotactic styrenic polymer with the brominating agent to produce a brominated syndiotactic styrenic polymer.

Method for making brominated syndiotactic styrenic polymers

Effective amounts of low molecular weight brominated polystyrenes unexpectedly provide good property retention and yet achieve desired flame retardance, for example, UL-94 VO in high impact polystyrene. In contrast, high molecular weight brominated styrene polymers (degree of polymerization equals 2,000) do not provide good property retention such as impact strength and toughness in high impact polystyrene. The degree of polymerization of the brominated polystyrenes of the present invention is generally from about 3 to about 20 and can have a considerable variation in the amount of halogenation. The high impact polystyrenes blended with the low molecular weight brominated polystyrenes are readily processed by conventional equipment.

Growing community of inventors

Macedonia, OH, United States of America

James C Gill