WO2000005304A1

WO2000005304A1 - Method for reducing odor during processing of flame retardant polymers

Info

Publication number: WO2000005304A1
Application number: PCT/US1999/016411
Authority: WO
Inventors: Elizabeth S. Papazoglou; Jay Kotak
Original assignee: Great Lakes Chemical Corporation
Priority date: 1998-07-21
Filing date: 1999-07-20
Publication date: 2000-02-03
Also published as: AU5115299A

Abstract

A method for reducing the odor formed during thermal processing of a thermoplastic polymer composition containing a tris(trihaloneopentyl) phosphate flame retardant additive is disclosed. The method comprises processing a polymer composition containing the thermoplastic polymer, the flame retardant additive, and a quantity of a hydrotalcite effective to reduce the odor formed during processing at an elevated temperature. The method is especially suited for processing polymers that must be processed above 230 °C, such as polypropylene, polybutylene terephthalate, and polycarbonate.

Description

TITLE

METHOD FOR REDUCING ODOR DURING PROCESSING

OF FLAME RETARDANT POLYMERS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application 60/093,588, filed July 21, 1998.

TECHNICAL FIELD This invention relates to methods for reducing the odor formed during processing of polymers that comprise a tris (trihaloneopentyl) phosphate flame retardant additive. In particular, this invention relates to reducing odor by adding a hydrotalcite to the polymer.

BACKGROUND OF THE INVENTION

Thermoplastic polymers can be modified by a number of flame retardant additives that either hinder ignition and/or reduce flame spread. In many of these applications it is preferred or mandatory to incorporate an additive into the polymer to improve its flame resistance or retardance. Although addition of flame retardant additives improves the flame retardant properties of polymers, flame retardant additives can adversely affect the physical properties of the polymer and may also make it more difficult to process the polymer.

Tris (trihaloneopentyl) phosphates, particularly tris (tribromoneopentyl) phosphate, are useful as flame retardant additives. These additives are melt blendable into many thermoplastic polymers and have minimal effect on the properties and processing of the polymer. Their exceptional heat stability produces materials with processing and storage stability. However, use these additives has been limited by a tendency for polymers incorporating them to develop objectionable odors, especially when processed at higher temperatures. An objectionable odor may also be produced if the residence time of the polymer in the heated portion of the extruder used to process the polymer/flame retardant additive composition is prolonged for any reason. The processing temperature referred to in this disclosure is the melt temperature of the polymer. The temperature of the polymer in the extruder is typically higher than temperature of the barrel of the extruder because of the force exerted on the polymer during extrusion heats the polymer above the barrel temperature . Although tris (trihaloneopentyl) phosphates are useful as flame retardant additives in thermoplastic polymers, such as polypropylene, they less acceptable if the polymer is to be processed at a temperature of 260°C than if it is processed at a temperature of 230°C. These materials have not been widely used in polymers such as polyesters, which are almost always processed at temperatures in excess of 250°C. Thus, a need exists for a method for controlling the odor produced when polymer compositions comprising tris- (trihaloneopentyl) phosphate flame retardant additives, particularly tris (tribromoneopentyl) phosphate, are processed at temperatures in excess of 230°C, and especially above 250°C or 260°C.

SUMMARY OF THE INVENTION We have discovered that the incorporation of a hydrotalcite into a polymer comprising tris (trihaloneo- pentyl) phosphate flame retardant additive reduces objectionable odors during processing, even at temperatures in excess of 250°C.

Miyata, U.S. Pat. 4,729,854 [EP 129,805] describes compositions comprising a thermoplastic resin, a halogen containing organic flame retardant additive and a hydrotalcite. The hydrotalcite is stated to effective in neutralizing any hydrogen halides involved during the processing of the resin. Although not being bound by any theory or explanation, it is believed that in the instant invention the hydrotalcite reacts with neutral tetrahalide and possibly other odoriferous residuals, thus reducing the odor. The effectiveness of the hydrotalcite in reducing the odor associated with a neutral halogenated species is surprising.

In one aspect the invention is a method for reducing the odor formed during the processing a thermoplastic polymer composition comprising a tris (trihaloneopentyl) phosphate flame retardant additive at elevated temperature. The method comprises processing the thermoplastic polymer composition at a temperature of at least 230°C, typically at least 250°C or 260°C; in which the thermoplastic polymer composition comprises a thermoplastic polymer, a tris (trihaloneopentyl) phosphate flame retardant additive, and a quantity of a hydrotalcite effective to reduce the odor formed during processing at the elevated temperature.

In another aspect the invention is a thermoplastic polymer composition comprising at least one thermoplastic polymer, at least one tris (trihaloneopentyl) phosphate flame retardant additive, and at least one hydrotalcite, in which the amount of the hydrotalcite present is effective to reduce the odor formed during processing at an elevated temperature .

A preferred tris (trihaloneopentyl) phosphate flame retardant is tris (tribromoneopentyl) phosphate. Preferred thermoplastic polymers are polypropylene, polyethylene, copolymers of propylene and ethylene, and mixtures and blends thereof. In a preferred embodiment the composition additionally comprises a flame retardant additive synergist, preferably antimony trioxide; a co-additive halogenated flame retardant additive having at least one halogen atom attached to an aliphatic carbon atom as part of its molecular structure, preferably tetrabromobisphenol- A-bis (2 , 3-dibromopropyl) ether and/or tetrabromobisphenol-S- bis (2 , 3-dibromopropyl) ether; and, optionally and preferably, a metallocene elastomer in an amount effective to prevent blooming of the tris (trihaloneopentyl) phosphate flame retardant additive.

DISCLOSURE OF THE INVENTION The tris (trihaloneopentyl) phosphate flame retardant additive comprises one or more of tris (trichloroneopentyl) phosphate; tris (dichlorobromoneopentyl) phosphate; tris- (chlorodibromoneopentyl) phosphate and tris (tribromoneopentyl) phosphate. The preferred phosphate flame retardant additive is tris (tribromoneopentyl) phosphate. Although tris (tribromoneopentyl) phosphate offers the optimum flame retardant performance, it is more prone to the evolution of objectionable odors.

The nature of the polymer, the degree of flame retardancy desired or required, the cost of the polymer, the costs of the various additives, the intended use for the flame retardant polymer, the presence or absence of other flame retardant additives and/or synergists, and the value in use of the flame retardant polymer are all factors that may influence the quantity of flame retardant additive or additives used. Generally, the compositions comprise from 1 to 20 parts by weight, preferably from 2 to 15 parts by weight, and most preferably from 3 to 10 parts by weight of tris (trihaloneopentyl) phosphate flame retardant additive .

The compositions may comprise any thermoplastic polymer or any mixture or blend of two or more such polymers. Examples of polymers which are useful include polyolefins, especially polypropylene and polyethylene, polystyrene, polyvinyl fluoride, polyvinyl chloride, poly- vinylidene fluoride, polyvinylidene chloride, polytetra- fluoroethylene, polychlorotrifluoroethylene, polyacrylo- nitrile, polymethyl methacrylate, polyoxymethylene, poly- phenylene oxide, polyphenyl sulfide, polycarbonate, polyethylene terephthalate (PET) , polybutylene terephthalate (PBT) , polycaprolactone (nylon 6) , polyhexamethylene adipamide (nylon 6/6) , epoxy resins, polyurethanes and cellulose acetate, or any mixture of two or more thereof. The preferred polymers are polyolefins, polycarbonate, and polyesters, such as PET and PBT.

The polyolefins (sometimes called "polyolefin resins") may be derived from a variety of monomers, especially propylene, ethylene, butene, iso-butylene, pentene, hexene, heptene, octene, 2-methyl propene, 2-methyl butene, 4- methylpentene, 4-methyl hexene, 5-methyl hexene, bicyclo- (2 , 2 , 1) -2-heptene, butadiene, pentadiene, hexadiene, isoprene, 2,3-dimethyl butadiene, 3,1-methyl pentadiene, 1,3,4-vinyl cyclohexene, vinyl cyclohexene, cyclopenta- diene, and the like. The polyolefins include copolymers produced from any of the foregoing monomers and the like, and include homopolymer blends, copolymer blends, homopolymer-copolymer blends, and blends containing minor amounts (less than 50 wt%) of one or more styrenic monomers or polymers, such as styrene and methylstyrene .

The preferred polyolefins are polypropylene and polyethylene, including atactic, syndiotatic and isotatic polypropylene and polyethylene, low density polyethylene, high density polyethylene, ultra-high density polyethylene, and linear low density polyethylene; block copolymers of ethylene and propylene; and random copolymers of ethylene and propylene. These polyolefins may be produced using a variety of processes known to those skilled in the art and are available from a variety of sources . The polymers may have a range of melt indexes (MI), but will typically have MI values in the range 0.5 to 30. The most preferred polyolefin is polypropylene.

Hydrotalcite compounds are layered double hydroxide compounds, which may be obtained from synthetic or natural sources. Preferably the hydrotalcite is a compound that satisfies the formula Mg₆Al₂ (OH) χ₆C0₃.4H₂0 or the formula Mg₄Al₂ (OH) ₁C0₃.3H₂0 (this formula has also been written as 6MgO .A1₂0₃.C0₂.12H₂0) . In its ionic form hydrotalcite may be written as [Mg₆Al₂ (OH) ₁₆] ²⁺ [C03] ^2~ . Hydrotalcites are commercially available from J.M.

Huber under the brand name Hysafe® 539 or from Reheis under the brand name of L-55RII. These are multilayered minerals comprising primarily a magnesium/aluminum hydroxy carbonate having a formula approximating to Mg₄.₅Al₂ (OH) _i3.5H₂0. The amount of hydrotalcite incorporated into the thermoplastic polymer may vary through a wide range, from 0.001 to 5.0 parts by weight, preferably from 0.01 to 1.0 parts by weight, based on 100 parts by weight of thermoplastic polymer. The amount of hydrotalcite used is generally proportional to the amount of phosphate flame retardant additive present. The ratio of the weight of phosphate flame retardant additive to the weight of hydrotalcite is normally in the range 40:1 to 3:1, preferably 20:1 to 6:1.

The hydrotalcite is preferably dispersed evenly through the polymer. The hydrotalcite normally has an average particle size of 1 to 10 microns, preferably 1 to 5 microns. Surface treatments, such as those disclosed in Miyata, U.S. Pat. 4,729,854, may be used, but are not essential .

The compositions preferably comprise a conventional anti-oxidant. Although the hydrotalcite reduces or eliminates the noxious odors formed during processing of a polymer comprising a tris (trihaloneopentyl) phosphate, the polymer may become discolored during the processing step. However, discoloration may be reduced by incorporating an anti-oxidant, preferably a phenolic anti-oxidant, into the composition. Other classes of anti-oxidants, such as amines, thioesters and phosphites may also be useful.

A wide range of phenolic anti-oxidants are known. These anti-oxidants, such as those described in Thermoplastic Polymers and Additives - Theory and Practice John T Lutz, Jr., ed, Marcel Dekker, 1989, are all potentially usef l. Representative phenolic antioxidants include: 2 , 6-di-t-butyl-4-methylphenol, 2, 6-di-t-butyl-4- sec-butylphenol, octadecyl 3, 5-di-t-butyl-4-hydroxy- cinnamate, 2 , 2-ethylidenebis- (4 , 6-di- t-butylphenol) , 2,2- methylenebis (4-methyl-6-t-butylphenol) , 4 , 4-butylidine- bis (6-t-butyl-m-cresol) , 4 , 4-methylenebis (2, 6-di-t-butyl- phenol) , 1,3, 5-tris (4- t-butyl-3-hydroxy-2 , 6-dimethy1- benzyl)s-triazine-2,4,6-(lH,3H,5H) trione, tetrakis- (methylene-3- [3, 5-di- t-butyl-4-hydroxyphenyl] propionate) - methane, 2, 2-oxamidobisethyl-3 (3, 5-di- t-butyl-4-hydroxy- phenyl) propionate, 1, 6-hexamethylenebis (3, 5-di- -butyl-4- hydroxyhydrocinnamate) , 1,3, 5-trimethyl-2, , 6-tris (3, 5-di- t-butyl-4-hydroxybenzyl) -benzene, tris (2-methyl-4-hydroxy- 5- t-butylphenyl) butane, 1,3, 5-tris (3, 5-di- -buty1-4- hydroxybenzyl) isocyanurate, 3, 5-di- t-butyl-4-hydroxy- cinnamic acid triester with 1, 3, 5-tris (2-hydroxyethyl) -s- triazine-2, 4 , 6- (1H, 3H, 5H) trione, and N, N-hexamethylene- bis (3 , 5-di- t-butyl-4-hydroxyhydrocinnamate .

Each of these may be useful, either alone or in combination with one or more other anti-oxidants, to reduce or eliminate discoloration during processing. However, these anti-oxidants may exert an antagonistic effect when used in the presence of the hydrotalcite and reduce the effectiveness with which it decreases the odor formation. This tendency is preferably minimized or avoided by routine experimentation designed to optimize the both choice of phenolic anti-oxidant (s) and the quantity used.

Typically polyolefins comprise a synergist for the flame retardant additive. Useful synergists include antimony trioxide, sodium antimonate, antimony pentoxide, zinc stannate, zinc hydroxystannate, zinc borate, and any mixtures of two or more thereof. Preferred synergists are antimony trioxide and zinc borate. In general the ratio of the weight of tris (trihaloneopentyl) phosphate flame retardant additive to the weight of synergist will be in the range 3:1 to 1:1, typically 2:1.

The compositions may also comprise various other additives, such as photostabilzers , thermal stabilizers, antistatic and nucleating agents, pigments, fillers, glass, and other materials known in the art.

A preferred combination of additives for use in polyolefins, especially in polypropylene, propylene/- ethylene copolymers, and mixtures and blends thereof, is disclosed in Papazoglou, WO 98/17718, incorporated herein by reference. The composition comprises: the polyolefin, preferably polypropylene; 3 to 10% by weight of at least one tris- (trihaloneopentyl) phosphate flame retardant additive, preferably tris- (tribromoneopentyl) phosphate; 0.5 to 5% of a co-additive halogenated flame retardant additive having at least one halogen atom attached to an aliphatic carbon atom as part of its molecular structure, preferably tetrabromobisphenol-A-bis (2 , 3-dibromopropyl) ether or tetra- bromobisphenol-S-bis (2 , 3-dibromopropyl) ether; and a flame retardant additive synergist selected from the group consisting of antimony trioxide, antimony pentoxide, zinc stannate, sodium antimonate, zinc hydroxystannate, and zinc borate, preferably antimony trioxide, in which the ratio of the weight of antimony trioxide to the total weight of the tris (trihaloneopentyl) phosphate and the co-additive is about 1:5 to 1:1. The processing of these compositions may produce an offensive odor, which is reduced or eliminated by incorporating a hydrotalcite into the composition. Compositions that comprise a polyolefin and a polar additive, particularly a polar flame retardant additive, such as tris (trihaloneopentyl) phosphate, may suffer from a tendency for the additive to "bloom" from the composition, i.e., to form a sticky exudate upon the surface of the composition. [A polar flame retardant additive is one that is polar relative to the polyolefin.] Addition of metallocene elastomers to polyolefins containing polar flame retardant additives produces a composition that resists blooming even at high heat aging temperatures. "Metallocene elastomers" are substantially linear ethylene/C₃-C₂o α-olefin copolymers, especially substantially linear ethylene/C₅-Cι₀ α-olefin copolymers, prepared by constrained geometry catalysis using metallocene catalysts, such as are disclosed in McKay, U.S. Patent No. 5,747,580, and Chum, U.S. Patent 5,677,383. These materials typically have an ultimate elongation of 700% or greater. Any metallocene elastomer that is compatible with the selected polyolefin is useful. Preferably it does not degrade the properties of the polyolefin. Preferred metallocene elastomers are α- octene/ethylene elastomers. Metallocene elastomers are available from DuPont Dow, Wilmington, DE, as the Engage® elastomers, such as Engage® 8180 elastomer and Engage® 8403 elastomer. These materials have: densities of about 0.863 g/cm³ to about 0.913 g/cm³; melt flow indices of about 0.5 dg/min to about 30 dg/min; differential thermal analysis melting peaks of about 49°C to about 107°C; ultimate tensile strengths of about 4.1 MPa to about 33.8 MPa; and ultimate elongations of about 700% to greater than 1000%.

Processing of compositions comprising a polyolefin, a tris (trihaloneopentyl) phosphate flame retardant additive, and a metallocene elastomer may produce an offensive odor, which can be reduced or eliminated by incorporating a hydrotalcite into the composition. The amount of elastomer used should be an amount effective to yield an improvement in the bloom resistance of the polymer. Typically, such amounts are about 2 to 5 parts by weight of the elastomer per 100 parts by weight of polyolefin. However, up to about 20 parts by weight of elastomer, preferably up to 15 parts by weight of elastomer, may be added to reduce blooming under severe conditions, such as heating at 100°C for seven days .

The effectiveness of any particular elastomer may vary depending upon the polyolefin and flame retardant or retardants selected. In addition, the selection of a specific elastomer will also depend upon the particular application specifications. Elastomers having the requisite properties for optimization of bloom inhibition and good physical performance may be selected by routine testing .

The compositions may be compounded using techniques well known in the art. A uniform composition is desirable if the optimum flame retardant additive performance is to be obtained. The use of a twin screw extruder is preferred to the use of a single screw extruder. It is also desirable to keep the extrusion temperature above the melting points of the polyolefin, the flame retardant additives, and any other additives. The extrusion temperature should not be so high as to accentuate the difference between the viscosities of the polyolefin and the additives. The polymer compositions containing flame retardant additives are often formulated as concentrates, known as "masterbatches, " comprising the polymer from 15 to 50% by weight of the tris (trihaloneopentyl) phosphate flame retardant additive, and a proportionate amount of the other additives. The concentrates are "diluted" with additional quantities of polymer prior to the processing step. However, the tendency to form obnoxious odors is greater in this type of procedure and the invention finds particular application in the preparation of master batches.

INDUSTRIAL APPLICABILITY The invention finds particular applications in processes by which polymers are fabricated into finished articles by molding processes. The invention also finds particular application in the formulation of polypropylene compositions and polyethylene terephthalate compositions used to form fibers. Tris (tribromoneopentyl) phosphate has not been used in polyethylene terephthalate fibers because of its tendency produce objectionable odors during processing. Fiber extrusion is carried out at relatively high temperature (250°C - 280°C) and involves high shear forces being applied to a polymer as well as a polymer having a high surface area. All these factors tend to exacerbate the problem of odor formation. Addition of hydrotalcite to the composition alleviates this problem, even when these elevated extrusion temperatures are used. The advantageous properties of this invention can be observed by reference to the following examples which illustrate, but do not limit, the invention.

EXAMPLES Glossary

Hysafe® 539 Hydrotalcite (J.M Huber, Borger, TX)

Irgafos® 168 Tris (2, 4-di- t-butylphenyl) phosphite (Ciba Additives, Ardsley, NY)

Irganox® 1010 Tetrakis [methylene (3, 5-di- -butyl-4- hydroxyhydrocinnamate] methane (Ciba Additives, Ardsley, NY) LC21FF Anti-oxidant comprising about ¹/₃ Irganox® 1010 and ²/₃ Irgafos® 12, a phosphite anti- oxidant having Formula I (Ciba Additives, Ardsley, NY)

Profax 6523 Polypropylene homopolymer (MI 12) (Montell Polyolefins)

Rynite® Thermoplastic polyethylene terephthalate resin (DuPont, Wilmington, DE)

Example 1 Polypropylene compositions were prepared in a base polymer containing Profax 6523 polypropylene resin (100 parts by weight), tris (tribromoneopentyl) phosphate (4 parts by weight) , and antimony trioxide (2 parts by weight) . The other components are shown in Table 1. The compositions were flood fed into a Haake 19"

(about 48 cm) conical twin screw extruder operated at 70 rpm. The temperature profile was 210°C at the barrel (3 zones total) and 210°C at the die. The melt temperature measure with a melt thermometer was 230-240°C (depending on measurement at the beginning or towards the end of the run) . The stranded material was passed through a 6 ft (about 1.83 M) cooling water bath at a temperature of about 10°C. The strands were pelletized and collected. The pelletized materials were allowed to dry overnight until all surface moisture had evaporated.

The compositions were extruded in a Randcastle RCP- 0625 extruder operated at 10 rpm with a single stand die at a melt temperature of 250-260°C. The extruder was closely monitored by the operator, who recorded the intensity of any odor involved during the processing operation. The results are summarized in Table 1. The compositions obtained from the Haake extruder were heat aged to simulate long residence time during molding of complicated articles. About 25 g of each composition was placed in an aluminum weighing cup and the cups placed in a recirculating oven. Three tests were run at temperatures of 200, 240 and 250°C measured by a thermocouple placed in the middle of the oven. The odor generated was judged subjectively. At 200°C, all materials had slight or no odor. At 240°C or 250°C, the odor matched the odor observed during the processing of the same compositions through the Randcastle extruder.

Table 1 Processing of Polypropylene at 230-240°C^a

^aIn Profax 6523 polypropylene resin (100 parts by weight), tris (tribromoneopentyl) phosphate (4 parts by weight), and antimony trioxide (2 parts by weight) .

Example 2

The polymer compositions indicated in Table 2 were prepared and processed into fibers. F5-372 is a high purity grade of the phosphate of Example 1. The compositions were precompounded in a Haake extruder with a melt temperature of 250°C (barrel temperature 230°C) . The material was then flood fed into a Randcastle extruder RCP- 0625 operated at 4 rpm. The die was a single strand die. The results are shown in Table 2.

TABLE 2 Rynite® PET Processed into Fibers at 280°C^ε

^aMelt temperature during fiber extrusion .

Having described the invention, we now claim the following and their equivalents .

Claims

CLAIMSWhat is claimed is:

1. A method for reducing the odor formed during processing of a thermoplastic polymer composition at elevated temperature, the method comprising: processing the thermoplastic polymer composition at a temperature of at least 230┬░C; in which: the thermoplastic polymer composition comprises a thermoplastic polymer, a tris (trihaloneopentyl) phosphate flame retardant additive, and a quantity of a hydrotalcite effective to reduce the odor formed during processing at the elevated temperature.

2. The method of claim 1 in which the tris (trihaloneopentyl) phosphate flame retardant additive is tris (tribromoneopentyl) phosphate.

3. The method of claim 1 or claim 2 in which the thermoplastic polymer composition is processed at a temperature in excess of 260┬░C.

4. The method of any of the preceding claims in which the thermoplastic polymer is a polyolefin.

5. The method of claim 4 in which the polyolefin is selected from the group consisting of polypropylene, polyethylene, copolymers of propylene and ethylene, and mixtures thereof.

6. The method of either claim 4 or 5 in which in that the polyolefin is processed so as to form polyolefin fibers .

7. The method of any of claims 1 to 4 in which the polymer composition comprises polyethylene terephthalate.

8. The method of any of claims 1 to 3 in which the thermoplastic polymer is polybutylene terephthalate.

9. The method of any of claims 1 to 3 in which the thermoplastic polymer is a polycarbonate.

10. The method of any of the preceding claims in which the polymer composition comprises from 1 to 20 parts of the tris (trihaloneopentyl) phosphate flame retardant additive per 100 parts by weight of the thermoplastic polymer .

11. The method of claim 10 in which the polymer composition comprises from 2 to 15 parts by weight of the tris (tribromoneopentyl) phosphate flame retardant additive.

12. The method of any of the preceding claims in which the polymer composition comprises from 0.001 to 5.0 parts by weight of a hydrotalcite.

13. The method of claims 12 in which the hydrotalcite has an average particle size from 1 to 10 microns.

14. The method of any of the preceding claims in which the polymer composition comprises a phenolic antioxidant .

15. A composition comprising at least one thermoplastic polymer, at least one tris (trihaloneopentyl) phosphate flame retardant additive and at least one hydrotalcite, in which the amount of the hydrotalcite present is effective to reduce the odor formed during processing at an elevated temperature.

16. The composition of claim 15 in which the tris (trihaloneopentyl) phosphate flame retardant additive is tris (tribromoneopentyl) phosphate.

17. The composition of claim 15 or claim 16 in which the thermoplastic polymer is a polyolefin.

18. The composition of claim 17 in which the polyolefin is selected from the group consisting of polypropylene, polyethylene, copolymers of propylene and ethylene and mixtures thereof.

19. The composition of claim 18 in which the composition comprises 3 to 10% by weight of the tris-

( trihaloneopentyl) phosphate flame retardant additive; 0.5 to 5% of a co-additive halogenated flame retardant additive having at least one halogen atom attached to an aliphatic carbon atom as part of its molecular structure; and a flame retardant additive synergist selected from the group consisting of antimony trioxide, antimony pentoxide, zinc stannate, sodium antimonate, zinc hydroxystannate, and zinc borate, in which the ratio of the weight of antimony trioxide to the total weight of the tris (trihaloneopentyl) - phosphate flame retardant additive and the co-additive is about 1:5 to 1:1.

20. The composition of claim 19 additionally comprising a metallocene elastomer in an amount effective to prevent blooming of the tris (trihaloneopentyl) phosphate flame retardant additive.

21. The composition of claim 15 or 16 in which the thermoplastic polymer is polyethylene terephthalate.

22. The composition of claim 15 or 16 in which the thermoplastic polymer is polybutylene terephthalate.

23. The composition of claim 15 or 16 in which the thermoplastic polymer is a polycarbonate.

24. The composition of any of claims 15 to 18 and 20- 23 comprising from 1 to 20 parts by weight of the tris (trihaloneopentyl) phosphate flame retardant additive.

25. The composition of claim 24 comprising from 2 to 15 parts by weight of the tris (tribromoneopentyl) phosphate flame retardant additive.

26. The composition of any of claims 15 to 25 comprising from 0.001 to 5.0 parts by weight of a hydrotalcite.

27. The composition of claim 26 in which the hydrotalcite has an average particle size of from 1 to 10 microns .

28. The composition of any of claims 15 to 27 additionally comprising a phenolic anti-oxidant.

29. A mater batch for a flame and bloom resistant composition comprising: (a) a polyolefin;

(b) a total of at least 25% by weight of at least one tris (trihaloneopentyl) phosphate flame retardant additive; (c) at least one metallocene elastomer; and (d) hydrotalcite; in which the ratio of the weight of phosphate flame retardant additive to the weight of hydrotalcite is about 20:1 to 6:1.