WO2000037552A1

WO2000037552A1 - Additive concentrates for olefinic polymers

Info

Publication number: WO2000037552A1
Application number: PCT/US1999/030764
Authority: WO
Inventors: Charles A. Tennesen; Shaun R. Seibel
Original assignee: Great Lakes Chemical Corporation
Priority date: 1998-12-22
Filing date: 1999-12-22
Publication date: 2000-06-29

Abstract

A master batch for a flame and bloom resistant polymer compositions is disclosed. The master batch contains at least 25 % by weight polar flame retardant additives and at least one elastomeric carrier resin as well as, optionally, anti-oxidants, flame retardant synergists, and other additives. Preferred elastomeric carrier resins are substantially linear ethylene/C5-C10 α-olefin copolymers prepared by constrained geometry catalysis using metallocene catalysts, especially α-octene/ethylene elastomers. A preferred polar flame retardant additive is tris- (tribromoneopentyl) - phosphate. Master batches containing up to 70 % by weight polar additives may be prepared.

Description

ADDITIVE CONCENTRATES FOR OLEFINIC POLYMERS

FTFT.Π OF TΠF T VFNTTON

This invention relates to flame resistant polyolefin compositions. More particularly, this invention relates to master batches for flame resistant polyolefin comprising an elastomeric carrier resin and one or more polar flame retardant additives.

^■RΆΓ ΠPOTT Π OF TTTF, τm/πwττnτj

The UL (Underwriters Laboratory) 94 test is commonly used to measure the flame retardancy of a polymer. In this test, a test specimen of polymer (either 5" x 1/8" or 5" x 1/16") is exposed vertically to the flame from a Bunsen burner for 10 seconds. The specimen is ignited at the bottom and burns up. If the specimen self-extinguishes within 30 seconds, a second 20 second application of the flame is made. Flaming droplets are allowed to fall on dry absorbent surgical cotton located 12 inches below the sample. If the average burn time is less than 5 seconds and the drips do not ignite the cotton, the polymer is classified as V-0 in the UL94 test. If the time is less than 25 seconds and the drips do not ignite the cotton, the polymer is classified as V-l. If the sample is self- extinguishing but the cotton is ignited, the material is classified as V-2.

Polyolefins, such as polypropylene and copolymers of propylene and ethylene, are useful in a variety of applications. In many of these applications it is preferred or mandatory to incorporate an additive into the polyolefin to improve its flame resistance or retardance. Although addition of flame retardant additives improves the flame retardant properties of polyolefins, addition of additives, particularly in amounts necessary to provide a V-0 rated composition in the UL94 test, can detract significantly from the physical properties of the poly- olefin. The use of flame retardant additives is usually a compromise between the desire for a particular degree of flame retardancy and the need to detract as little as possible from the desirable properties of the polyolefin. The production of a polyolefin, particularly a polypropylene composition, that can achieve a V-0 rating in the UL94 test without detracting from the physical properties of the polymer has been an objective of the industry for many years. Although a V-0 rated polypropylene can be produced by incorporating flame retardant additives, these additives bloom from the polymer.

Blooming, or plating out, is the separation of the additive from the polyolefin matrix as evidenced by a surface film on a molded specimen of polyolefin that contains the additive. Blooming may occur during cooling of the article in the mold, or may be induced via heat aging at elevated temperatures and/or extended times. The blooming problem is particularly pronounced and difficult to overcome at relatively high heat aging temperatures, that is at heat aging temperatures above approximately 70°C. Because blooming is believed caused the fact that the additive is more polar than the polymer to which it has been added, blooming is a function of both the additive and the polymer to which it is added. Blooming of polar additives is an especially severe problem in polypropylene, a highly non-polar polymer.

Blooming of the flame retardant additive not only mars the appearance of the final product but may also reduce the flame resistant properties of the polymer over time due to loss of the flame retardant additive. Many electrical applications for flame retardant polymers require RTI (Relative Thermal Index) ratings that involve 18 months heat aging without a loss of physical properties and flame retardant performance. If the additive blooms from the polymer, the polymer can not achieve the required RTI rating.

Tris- (trihaloneopentyl) phosphates, especially tris-

(tribromoneopentyl) phosphate, have been proposed for use in polyolefins. These additives are melt blendable into polypropylene and have minimal effect on the properties and processing of the polymer. Their exceptional heat stability produces material with processing and storage stability. However, even when they are used with a synergist for halogenated flame retardant additives, such as antimony trioxide, these additives can only achieve a V- 2 rating at acceptable addition levels. A V-0 rating can only be achieved by increasing the amount of flame retardant additive and synergist to levels at which blooming becomes a serious problem. Scholer and Papazoglou, U.S. Patent Appln. Ser. No.

09/189,259, filed 11/10/98, incorporated herein by reference, discloses flame resistant polyolefins containing one or more polar flame retardant additives that are made bloom resistant by adding a bloom inhibiting amount of an elastomer. The preferred elastomers are substantially linear ethylene/C₃-C₂₀ α-olefin copolymers, especially substantially linear ethylene/C₅-C₁₀ α-olefin copolymers, prepared by constrained geometry catalysis using metallocene catalysts. Substantially linear α-octene/- ethylene copolymers are more preferred. Preferred polyolefins are polypropylene and propylene/ethylene copolymers. A preferred polar flame retardant additive is tris- (tribromoneopentyl) phosphate . The use of concentrated batches, known as "master batches," of polyolefin and additive and subsequent letting down (dilution) of this concentrate with polyolefin is a route to achieving a well-mixed product of polyolefin and polar additives. Because of the low compatibility between polypropylene and its ethylene copolymers with polar additives, master batches for these materials are typically prepared using a carrier resin, such as a polyolefin, rather than the polymer into which the flame retardant additive or additives is to be incorporated. However, polyolefins typically do not accept high levels of polar additives, and the resulting polyolefin/additive mixtures are difficult to process. Thus, the master batch typically comprises only about 5 to 20%, preferably from 10 to 20%, of the polar flame retardant additive or additives.

A master batch comprising more than 25% of polar additives would allow economies in the manufacture of flame retardant polymers. Thus, a need exists for master batches comprising a compatible mixture of a carrier resin and more than 20% of polar additive or additives in which the carrier resin does not adversely affect the properties of the final product.

SUMMARY QF THE TNVFiNTTON In one aspect, the invention is mater batch for flame and bloom resistant polymers comprising:

(a) a total of at least 25% by weight of one or more additives selected from the group consisting of polar additives, flame retardant synergists, and mixtures thereof; and

(b) at least one elastomeric carrier resin; wherein at least one polar additive is a polar flame retardant additive. Preferred elastomeric carrier resins are α-octene/- ethylene elastomers. A preferred polar flame retardant additive is tris- (tribromoneopentyl) phosphate . A preferred polar additive is hydrotalcite. The master batch comprises a total of at least 25% by weight, preferably at least 50% by weight, more preferably at least 60% by weight, and even more preferably at least 70% by weight, of one or more additives selected from the group consisting of polar additives and flame retardant synergists. At least 70% by weight polar additives may be processed into the elastomeric carrier resin of the invention, whereas extreme difficulty was observed while processing these additives into polypropylene homopolymer at levels of 25% by weight. This makes the master batches of this invention more economical and effective compared to master batches based on traditional olefin resin systems. The elastomeric carrier resins also have been shown to be effective antibloom agents for polar additives in polyolefins, especially polypropylene and ethylene/- propylene copolymers. Thus, the master batches offer a combination of good processability during master batch compounding, economy, and reduced additive blooming in the final flame retardant polymer.

In another aspect, the invention is a method for preparing a flame resistant polymer, the method comprising adding the master batch to a polyolefin.

DISCLOSURE QF THF, TNVF,NTTON

As disclosed in Scholer and Papazoglou, U.S. Patent Appln. Ser. No. 09/189,259, filed 11/10/98, incorporated herein by reference, addition of certain elastomers to polyolefins containing polar flame retardant additives produces a polyolefin that resists blooming even at high heat aging temperatures. It has now been found that these elastomers can be used as carrier resins to form master batches comprising more than 20% of polar additive or additives in which the carrier resin does not adversely affect the properties of the final product. Master batches comprising up to about 73% of polar additive in the elastomeric carrier resin can be prepared. Although the polymer into which the master batch is to be added may be present in the master batch in addition to the elastomeric carrier resin, the elastomeric carrier resin should comprise at least 70%, preferably 80%, and more preferably 90%, of the total amount of elastomeric carrier resin and polymer to which the master batch is to be added present in the master batch.

Any elastomer that is compatible with the selected polyolefin is useful as an elastomeric carrier resin. Preferably it does not degrade the properties of the polyolefin. These materials typically have an ultimate elongation of 700% or greater.

The preferred elastomers are substantially linear ethylene/C₃-C₂₀ α-olefin copolymers, especially substantially linear ethylene/C₅-C₁₀ α-olefin copolymers, prepared by constrained geometry catalysis using metallocene catalysts. These copolymers are disclosed in McKay, U.S. Patent No. 5,747,580, and Chum, U.S. Patent 5,677,383, incorporated herein by reference. These copolymers are sometimes known as "metallocene elastomers."

More preferred elastomers are substantially linear α- octene/ethylene copolymers available as the Engage^® polyolefin elastomers from DuPont Dow Elastomers, Wilmington, DE . 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%.

The amount of elastomer used in the final polymer 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 additive or additives 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 polyolefin into which the master batch is incorporated (sometimes also referred to as "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- methylhexene, bicyclo- (2, 2, 1) -2-heptene, butadiene, pentadiene, hexadiene, isoprene, 2, 3 -dimethyl butadiene, 3,1-methyl pentadiene, 1, 3 , 4-vinylcyclohexene, vinyl- cyclohexene, cyclopentadiene, styrene and methyl styrene. The polyolefins include copolymers produced from two or more of any of the foregoing monomers and the like, and further include homopolymer blends, copolymer blends, and homopolymer-copolymer blends. The preferred polyolefins are polypropylene and polyethylene, including atactic, syndiotactic and isotactic polypropylene and polyethylene, low density polyethylene, high density polyethylene, linear low density polyethylene, block copolymers of ethylene and propylene, and random copolymers of ethylene and propylene. Polypropylene, propylene/ethylene copolymers, and mixtures and blends thereof are more preferred. With respect to these polymers and copolymers, the term " mixtures" includes blends. These polyolefins may be produced using a variety of catalytic processes. The polyolefins useful in this invention may be produced by any of these processes including metallocene catalyzed processes. The polymers may have a range of melt indexes (MI) but will typically have MI values in the range 4 to 30.

The flame retardant additive or additives may be any polar flame retardant additives described in the literature. A useful review of flame retardant additives is included in Thermoplastic Polymer Addi ives - Theory and Practice, John T. Lutz, Jr., ed. , Marcel Dekker, Inc., 270 Madison Avenue, New York (1989) .

As used herein, a polar additive is an additive that is polar relative to the polyolefin. As used herein, a polar flame retardant additive is a flame retardant additive (also called a flame retardant) that is polar relative to the polyolefin. Thus, the term polar additive includes polar flame retardant additives as well as other polar additives, such as polar photostabilizers, polar thermal stabilizers, polar pigments, etc. Polar flame retardant additive does not refer to the various flame retardant synergists for halogenated flame retardant additives, such as antimony trioxide and zinc borate .

Examples of polar flame retardant additives that may be useful are: decabromodiphenyl oxide, available from Great Lakes Chemicals under the designation Decabrom; tetrabromo is-phenol-A-jis- (2 , 3-dibromopropyl ether), available from Great Lakes Chemical Corporation under the designation PE-68; tetrabromo- is-phenol-S-Jbis- (2 , 3- dibromopropyl ether) , available as under the designation Non-Nen-52 from Manac Inc. of Japan; adducts of hexachloroentadiene and cyclooctadiene, such as Dechlorane Plus available from Oxychem; ethylene bis- (bis-bro o- norborane) dicarboximide, available from Albermarle Corporation under the designation BN451; dibromoethyl- dibromocyclohexane, available from the Ethyl Corporation under the designation BCL 462; pentabromochlorocyclohexane, available from the Ethyl Corporation under the designation FR651P; FM 836, a halogenated phosphate ester sold by the Great Lakes Corporation; and halogenated paraffins, especially chloroparaffins and bromoparaffins, such as those available from the Ferro Corporation under the designation Bromchlor. The total amount of polar flame retardant additive or additives present in the final product typically does not exceed about 15 parts by weight of polar flame retardant additive or additives per 100 parts by weight of polyolefin.

Other polar flame retardant additives include tris-

(trihaloneopentyl) hosphates, aromatic and aliphatic halogenated phosphate esters, and other halogenated phosphates, and combinations thereof. Preferred tris- (tri- haloneopentyl) phosphates are tris- (trichloroneopentyl) - phosphate, tris- (chlorodibromoneopentyl) phosphate, tris-

(dichlorobromoneopentyl) phosphate, tris- (tribromoneo- pentyl) phosphate, and combinations thereof. The most preferred tris- (trihaloneopentyl) phosphate is tris- (tri- bromoneopentyl) phosphate [tris- (3-bromo-2 , 2-bis (bromo- methyDpropyl) phosphate] . In addition, various flame retardant synergists for halogenated flame retardant additives may be used in the final flame retardant polymer. 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. Flame retardant synergists are may be incorporated into the master batch, or added during processing of the final flame retardant polymer.

Zinc borate can be used to substitute for 40 to 60% of an antimony containing synergist on a weight basis. This produces a lighter product due to the specific gravity difference between zinc borate and the antimony containing synergist. Zinc borate is commercially available under the designation Firebrake^® 415 flame retardant synergist.

Incorporation of a hydrotalcite into a polymer with a tris- (trihaloneopentyl) phosphate flame retardant additive reduces the formation of objectionable odors during processing, even at temperatures in excess of 250°C. The use of hydrotalcite as a stabilizer for halogen-containing organic flame retardant additives is disclosed in Miyata, U.S. Pat. No. 4,727,854, incorporated herein by reference. 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) ₁₆C0₃.4H₂0 or the formula Mg₄Al₂ (OH) ₁₂C0₃.3H₂0 (sometimes written as

6Mg0.A1₂0₃. C0₂.12H₂0) . In its ionic form, hydrotalcite may be written as [Mg₆Al₂ (OH) ₁₆] ²⁺ [C03] ^" . The hydrotalcite is preferably dispersed evenly through the polymer. Preferably hydrotalcite having an average particle size in the range of 1 to 10 microns, more preferably 1 to 5 microns, is used. Hydrotalcites may be purchased from J.M. Huber under the name Hysafe 539 or from Reheis under the name of L- 55RII. These are multilayered minerals comprising primarily a magnesium/aluminum hydroxy carbonate having a formula approximating to Mg₄₅A1₂ (OH) ₁₃.5H₂0.

The amount of hydrotalcite incorporated into the final flame retardant polymer may vary through a wide range, from 0.001 to 5.0, and more preferably from 0.001 to 1.0 parts by weight. The amount of hydrotalcite used is generally proportional to the amount of phosphate ester present. The ratio of the weight of phosphate ester to the weight of hydrotalcite is normally in the range 40 : 1 to 3 : 1 and preferably in the range 20:1 to 6:1. The amount of hydrotalcite in the master batch will be the amount required to produce the desired hydrotalcite concentration in the final flame retardant polymer.

The compositions may also comprise an anti-oxidant . A wide variety of anti-oxidants are known and used in the art. These anti-oxidants are described, for example, in Thermoplastic Polymers and Additives - Theory and Practice edited by John T Lutz Jr. and published by Marcel Dekker Inc. in 1989.

Although hydrotalcite reduces or eliminates the noxious odors formed during the processing of polymers with a tris- (trihaloneopentyl) phosphate flame retardant additive, the polymers may become discolored during processing. Discoloration is reduced by incorporating an anti-oxidant, preferably a phenolic anti-oxidant, such as 2, 6-di- t-butyl -4 -methyl phenol, 2 , 6-di- t-butyl-4-sec-butyl- phenol, octadecyl 3 , 5-di- t-butyl-4-hydroxycinnamate, 2,2- ethylidene-bis- (4, 6-di- t-butylphenol) , 2, 2-methylene-bis (4- methyl-6- -butylphenol) , 4 , 4-butylidine-bis (6- t-butyl-zn- cresol) , 4 , 4-methylene-bis (2 , 6-di- t-butylphenol) , 1,3,5- tris (4- -butyl-3-hydroxy-2 , 6-dimethylbenzyl) -s-triazine-

2,4,6- (1H,3H,5H) -trione, tetrakis (methylene-3- [3, 5-di- t- butyl-4-hydroxyphenyl] propionate) methane, 2 , 2-oxamido-jbis- ethyl-3- (3 , 5-di- -butyl-4 -hydroxypheny1) propionate, 1,6- hexamethylene-bis (3 , 5-di- -butyl-4-hydroxyhydrocinnamate) ,

1,3, 5-trimethyl-2,4, 6- tris (3, 5-di- t-butyl-4-hydroxybenzyl) - benzene, tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane,

1,3,5- ri (3 , 5-di- -butyl-4-hydroxybenzyl) isocyanurate,

3 , 5-di- t-butyl-4 -hydroxycinnamic 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- -butyl-4 -hydroxyhydro- cinnamate, into the composition. Other classes of anti- oxidants such as amines, thioesters and phosphites may also be useful. Any of these may be useful either alone or in combination with one or more other anti-oxidants in reducing or eliminating any discoloration that may occur during the processing of the polymer. 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 experiment designed to optimism the choice of phenolic anti-oxidant (s) and the quantity of same which are used. The final flame retardant polymer may also comprise various other additives, such as photostabilizers, thermal stabilizers, antistatic and nucleating agents, pigments, fillers, glass, and other materials known in the art. Photostabilizers and thermal stabilizers include, for example, those available from Ciba-Geigy as Irganox^® stabilizers and Tinuvin^® stabilizers. Synergists, hydrotalcite, anti-oxidants, and other additives may be incorporated into the master batch in appropriate amounts or added to the final polymer during processing.

The amount of polar flame retardant additive used in the final flame retardant polymer should be an amount effective to yield the desired flame resistance of the polymer. Amounts will vary depending upon the particular flame retardant additives and polyolefin used and on the UL94 rating desired. The combination of additives may optimized using routine experimentation to achieve the particular goals desired. The nature of the polymer, the degree of flame retardancy required, the cost of the polymer, the costs of the various additives, the intended use for the flame retardant polymer, and the value in use of the flame retardant polymer are all factors that may influence the combination of additives selected.

A preferred combination of additives for use in flame retardant polyolefins, especially in polypropylene, propylene/ethylene copolymers, and mixtures and blends thereof, is disclosed in Papazoglou, WO 98/17718 [U.S. Appln. Ser. No. 08/951,931], 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 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 master batches may be compounded using techniques well known in the art. It is desirable to achieve uniformity of the formulation if the optimum 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 elastomeric carrier resin, 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. Extrusion temperatures below

230°C are generally preferable. The master batch may be prepared in one step or in several steps. When the master batch is prepared in one step, all the additives are incorporated into the carrier resin in the same processing step. When several steps are used, the flame retardant additive or additives are typically incorporated into the carrier resin in the first processing step. Additional additives are incorporated into the flame retardant additive containing master batch in an additional processing step or steps. By this procedure, final master batches containing different additive packages may be formulated for specific applications from an initial flame retardant containing master batch.

TTsrousTRTAT. ΆPPT.TΓΆΏTT.TTV The master batches are useful in the preparation of flame retardant polymers, especially polyolefins. The master batch comprises one or more flame retardant additives and may comprise additional flame retardant synergists and/or other additives, such as hydrotalcite and anti-oxidants. It may be comprise the complete " additive package" so that it is unnecessary to add additional additives during processing of the final.

The master batch may be "letdown," i.e., incorporated into the final flame retardant polymer, by procedures well known to those skilled in the art. A physical mixture of mater batch and polymer can be prepared by, for example, using a tumble mixer and fed an extruder. Alternatively, the master batch and the polymer can be fed simultaneously into an extruder using loss-in weight feeders. The relative amounts of master batch and polymer used will depend on the level of additives in the master batch and the additive level desired in the final polymer. Additional additives, such as flame retardant synergists, hydrotalcite, and anti-oxidants, may be added at this time, if desired.

It is desirable to achieve uniformity of the formulation if the optimum flame retardant and bloom resistant 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 polymer, the flame retardant additives, the elastomer 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. Extrusion temperatures below 230°C are generally preferable. The final flame retardant polymer is typically quenched in a water and pelletized following extrusion. Flame retardant polyolefins, especially bloom retardant and bloom retardant polypropylene, are especially useful for articles fabricated by molding processes, particularly for molded products used in the electrical industry. The advantageous properties of this invention can be observed by reference to the following examples which illustrate, but do not limit, the invention.

FXΆMPT.FS Glossary

DLPDP Dilauryl thio dipropionate Engage^® 8180 Elastomer (density, 0.863 g/cm³; Mooney viscosity at 121°C, 35; melt flow index, 30 dg/min; shore hardness, 66; DSC melting peak, 49°C; ultimate elongation, >800%) (DuPont Dow, Wilmington, DE)

Engage^® 8403 Elastomer (density, 0.913 g/cm³; Mooney viscosity at 121°C, 1.5; melt flow index, 0.5 dg/min; shore hardness, 96; DSC melting peak, 107°C; ultimate elongation, 700%) (DuPont Dow, Wilmington, DE)

Exact^® 4033 Elastomer (Exxon)

Exxon^® 7032 Ethylene/propylene copolymer (about 9% ethylene) (Exxon Chemicals)

Irgafos^® 168 Tris (2 , 4-di- -butylphenyl) phosphite (Ciba- Geigy) Irganox^® 1010 Tetrakis [methylene (3, 5-di- t-butyl-4- hydroxyhydrocinnamate] ethane (Ciba-Geigy) Non-Nen-52 Tetrabromo-jis-phenol-S-Jis- (2,3)- dibromopropyl ether (Manac)

PE-68 Tetrabromo-Jis-phenol-A-jbis- (2,3)- dibromopropyl ether (Great Lakes Chemical)

Profax^® 6523 Polypropylene homopolymer (Himont) Sample Preparation

All additives, flame retardant additives and stabilizers in powder form were dry blended in a bag with the polypropylene and elastomer pellets for approximately 1 min. The contents of the bag were flood fed into a Haake 19" conical, partially intermeshing, counter rotating, twin screw extruder operating at the following conditions:

T(zone 1) = T(zone 2) = T(zone 3) = 210°C T(die) = 220°C

Feed water: on Screw speed = 60 rp

The extruded strands were quenched in a 6 ' water bath and then pelletized. The pellets were air dried overnight to remove surface moisture, and subsequently injection molded in a Battenfeld 800/315CDC injection molding machine, operating at the following conditions:

T(zone 1) = T(zone 2) = T(zone 3) = 210°C;

T (nozzle) = 215°C

T(mold) = 40°C Cooling time = 20 sec Shot size = 3.4

The mold used was a simple cavity mold producing a square plaque (2" x 2" x 1/8"), two 1/8" UL bars (1/2" x 5" x 1/8"), one 1/16" UL bar (1/2" x 5" x 1/16"), one 3/16" UL bar (1/2" x 5" x 3/16"), one ASTM tensile specimen (3/4" x 6" x 1/8"), one ASTM Izod specimen (1/2" x 2" x 1/8"), and one Oxygen Index specimen (1/4" x 5" x 1/8").

All compositions exhibited stable processing with no surging or torque variations during extrusion. No volatiles were emitted during processing at extrusion or the injection mold. No discoloration or other signs of thermal degradation was observed during processing. Bloom Determination

Molded plaques of the desired formulations were (2" x 2" x 1/8") were oven aged at 100°C in a recirculating oven for either 8 days or 28 days. The plaques were then placed into a 400 mL beaker containing approximately 50 mL of dichloromethane for 3 min with continuous stirring. The solvent was transferred into a pre-weighed cup and allowed to evaporate. The residue was assumed to be bloomed flame retardant material .

Flame Retardance Measurements

Oxygen index is defined as the minimum concentration of oxygen, expressed in volume percent, that will just support combustion. Oxygen index measurements were made following ASTM D-2863 as described in Papazoglou, WO 98/17718,. UL94 measurements were carried out using standard procedures.

Examples 1-5

These examples illustrate bloom inhibition in poly- propylene compositions containing different levels of elastomeric additives and 4% tris- (3 -bromo-2 , 2-bis (bromo- methyl) propyl) phosphate flame retardant additive. Results are given in Table 1.

TABLE 1

Example

Profax^® 6523 4^ 92% 89^ 92% 89%

Tris (3 -bromo-2, 2- 4% 4% 4% bis (bromomethyl) - propy1) phospha e

Antimony Trioxide 2% 2% 2% 2%

Engage^® 8180 2%

Engage^® 8403 2% 5%

Avg. bloom after 0.0134 0.0059 0.0022 0.0120 0.0102

8 days (g)

Avg. bloom after 0.0279 0.0161 0.0119 0.0156 0.0201

28 days (g)

UL94 Rating @ 1/8" V-2 V-2 V-2 V-2 V-2

Ave . Burn time 6.8 2.3 3.6 4.2 3.2

@ 1/8" (sec)

UL94 Rating @ 1/16" V-2 V-2 V-2 V-2

Ave . Burn time 3.6 2.3 2.8 3.0 4.3

@ 1/16" (sec)

Examples 6-10 These examples illustrate bloom inhibition in compositions containing two different levels of elastomeric additives and 3% tetrabromo-bis-phenol-A-Jbis- (2 , 3) -dibromo- propyl ether flame retardant . Results are given in Table 2. TABLE 2

10 Profax^® 6523 96% 94% 91% 94% 91%

PE-68 3% 3% 3% 3% 3%

Antimony Trioxide 1% 1% 1%

Engage^® 8180 5%

Engage^® 8403 2% 5% Avg. bloom after 0.0276 0.0099 0.0146 0.0154 0.0152 8 days (g)

Avg. bloom after 0.0475 0.0233 0.0264 0.0214 0.0186 28 days (g)

UL94 Rating @ 1/8" V-2 V-2 V-2 V-2 V-2

Ave . Burn time 1.0 1.5 1.0 1.5 1.0 @ 1/8" (sec)

UL94 Rating @ 1/16" V-2 V-2 V-2 V-2 V-2

Ave . Burn time 1.0 1.5 0.7 1.0 1.0 @ 1/16" (sec)

Examples 11-15

These examples illustrate bloom inhibition in polypropylene compositions containing different levels of elastomeric additives and 8% tris- (3-bromo-2 , 2-bis (bromo- methyl) propyl) hosphate flame retardant. Results are given in Table 3. TART.F 3

Example 11 12 13 14 15 Profax^® 6523 88% 86% 83' 86% 83%

Tris (3 -bromo-2, 2- 8% 8% 8% 8% bis (bromo-methyl) propyl) phosphate

Antimony Trioxide 4% 4% 4% 4% 4%

Engage^® 8180 2% 5% Engage^® 8403 2% 5%

Avg. bloom 0.0141 0.0084 0.0049 0.0141 0.0104 after 8 days (g) Avg. bloom 0.0240 0.0389 0.0093 0.0173 0.0343 after 28 days (g)

UL94 Rating @ 1/8" V-2 V-2 V-2 V-2 V-2 Ave. Burn time 2.7 4.4 2.2 2.5 3.0 @ 1/8" (sec)

UL94 Rating @ 1/16" V-2 V-2 V-2 V-2 V-2 Ave. Burn time 1.3 1.9 1.8 1.7 3.7 @ 1/16" (sec)

Example 16-20

These examples illustrate bloom inhibition in poly- propylene compositions containing different levels of elastomeric additives and 9% tris-tetrabromo-bis-phenol-A- is- (2, 3) -dibromopropyl ether flame retardant. Results are given in Table 4. TABTiF 4

Example 16 17 18 19 20 Profax^® 6523 87% 85% 82% 85% 82% PE-68 9% 9% 9% 9% 9%

Antimony Trioxide 4% 4% 4% 4% 4% Engage^® 8180 2% 5% Engage^® 8403 2% 59.

Avg. bloom after 0.0436 0.0178 0.0365 0.0324 0.0415

8 days (g)

Avg. bloom after 0.0681 0.0602 0.0777 0.0602 0.0650

28 days (g)

UL94 Rating @ 1/8" V-0 V-0 V-0 V-0 V-0

Ave. Burn time 0 0 0 0 0

@ 1/8" (sec)

UL94 Rating @ 1/16" V-0 V-0 V-0 V-0 V-0

Ave . Burn time 0

1/16" (sec)

Example 21-22

These examples illustrate bloom inhibition in a composition that contains a mixture flame retardant materials similar to that disclosed in WO 98/17718. Results are given in Table 5.

TABLE

Example 2 22 Profax^® 6523 88% 83%

Tris (3-bromo-2, 2-bis (bromo- 4% 4% methyl) propyl ) phosphate Non-Nen 52 4% 4%

Antimony Trioxide 4% 4%

Engage^® 8180 -- 5%

Avg. bloom after 8 days (g) 0.0188 0.0120

Avg. bloom after 28 days (g) 0.0266 0.0190 UL94 Rating @ l/8" V-0 V-0

Ave. Burn time @ 1/8" (sec) 0 0

UL94 Rating @ 1/16" V-0 V-0

Ave. Burn time @ 1/16" (sec) 0 0

Example 23-24 These examples illustrate bloom inhibition and flame retardance in a composition that contains a mixture flame retardant materials similar to that disclosed in WO 98/17718. Results are given in Table 6.

TABT.F 6

Exampl 22 24 Profax^® 6523 88% 83%

Engage^® 8180 -- 5%

Tri (3-bromo-2 , 2-bis (bromo- 3% 3% methyl)propyl) phosphate

PE-68 5% 5%

Antimony Trioxide 4% 4%

Avg. bloom after 8 days (g) 0.0197 0.0140

Avg. bloom after 28 days (g) 0.0295 0.0200 Oxygen Index 31 30.6

UL94 Rating @ 1/8" V-0 V-0

Ave. Burn time @ 1/8" (sec) 0 0

UL94 Rating @ 1/16" V-0 V-0

Ave . Burn time @ 1/16" (sec) 0 0

Examples 25-28

These examples illustrate that higher amounts of elastomer can be used to reduce bloom.

TARTiF 7

Example 25 2£ 22 28_ Profax^® 6523 76% 73% 70% 73%

Engage^® 8180 12% 12% 12% 12%

Tris (3-bromo-2, 2-bis 3% 3.75% 4.5% (bromo-methyl)propyl) phosphate

PE-68 5% 6.25% 7.5% 10% Antimony Trioxide 4% 5% 6% 5%

Avg. bloom after 0.0177 0.0142 0.0282 0.0306 7 days @ 100°C (g) Oxygen Index 30.9 32.4 33.1 32

UL94 Rating @ 1/16" V-2 V-0 V-0 V-0

Ave. Burn time @ 1/16" 0 0 0 0.1 0.3 (sec)

Iv.nή impact ft-lb/in 1.34 1.21 1_2 1 -5

Example 29-30

These examples illustrate bloom inhibition and flame retardance in a composition that contains a propylene/- ethylene copolymer. Results are given in Table 8.

TΆRT.F, a

F-x-ampl e _ 9_ _3 Exxon^® 7032 Copolymer 81.4 76.4

Engage^® 8180 -- 5%

Tris (3-bromo-2, 2-bis (bromo- 4.5% 4.5% methyl)propyl) phosphate

PE-68 7.5% 7.5%

Antimony Trioxide 6% 6%

Irganox^® 1010 0.15 0.15

Irgafos^® 168 0.15 0.15

DLPDP 0.3 0.3

Avg. bloom after 0.0185 0.0148 7 days @ 100°C (g)

Oxygen Index 30.9 30.7

UL94 Rating @ 1/8" V-0 V-0

Ave. Burn time @ 1/8" (sec) 0 0

UL94 Rating @ 1/16" V-0 V-0

Ave. Burn time & 1/1 " (sec] __Q Ω

Example 31

A master batch was prepared using a ZSK 30 mm co- rotating intermeshing twin screw extruder. The elastomer and the additives were metered in using loss-in weight feeders. Elastomer pellets were fed into the main feed throat using a Acrison loss-in weight feeder. The flame retardant additive or additives was fed into the main feed throat using a K-tron loss-in weight feeder. In the absence of flame retardant additive, Engage^® 8180 elastomer can be extruded by a barrel temperature of 150°C and a screw speed of 250 rpm with a 70% torque requirement.

A master batch was formed by extruding tris (3-bromo-

2 , 2 -bis (bromomethyl ) propyl ) phosphate flame retardant additive into Engage^® 8180 elastomeric carrier. A master batch containing about 73% of flame retardant additive was prepared using feed rates of 40 lb/hr of flame retardant additive and 15 lb/hr of elastomer. Torque of the extruder was reduced compared to the blank elastomer. An extruder process temperature of 120° was used, which is below the melting point of the flame retardant (180°C) .

Example 32

A master batch was formed by extruding a 5:3 mixture of tris (3-bromo-2 , 2-bis (bromomethyl) propyl) phosphate flame retardant additive and PE-68 flame retardant additive into Engage^® 8180 elastomeric carrier using the procedure described in Example 31.

A barrel temperature of 80°C was used. Recorded melt temperature was 95°C. Screw speed varied between 150-250 rpm. The extruder overtorqued at temperatures below 80°C.

Example 33

A series of master batches was prepared using Haake 19" conical, partially intermeshing, counter rotating, twin screw extruder.

(a) A mixture of 79.4% Exact^® 4033 elastomeric carrier, 4.5% tris (3 -bromo-2 , 2-bis (bromomethyl) propyl) - phosphate flame retardant additive, 7.5% PE-68 flame retardant additive, and 8.60% antimony trioxide flame retardant synergist concentrate (70% antimony trioxide and 30% polypropylene) were extruded to produce a master batch containing 20.6% of additives in the elastomeric carrier.

(b) A mixture of 79.4% of the master batch from step (a), 4.5% tris (3 -bromo-2, 2-bis (bromomethyl) propyl) phosphate flame retardant additive, 7.5% PE-68 flame retardant additive, and 8.60% antimony trioxide flame retardant synergist concentrate (70% antimony trioxide and 30% polypropylene) were extruded to produce a master batch containing 34.15% of additives in the elastomeric carrier. (c) The procedure of step (b) was repeated using 79.4% of the master batch from step (b) in place of the master batch of step (a) to produce a master batch containing 45.4% of additives in the elastomeric carrier.

(d) The procedure of step (b) was repeated using 79.4% of the master batch from step (c) in place of the master batch of step (a) to produce a master batch containing 54.7% of additives in the elastomeric carrier.

(e) The procedure of step (b) was repeated using 79.4% of the master batch from step (d) in place of the master batch of step (a) to produce a master batch containing 62.4% of additives in the elastomeric carrier.

Example 34

A master batch containing about 20.00% Exact^® 4033 elastomeric carrier, about 10.00% Profax^® 6523 polypropylene homopolymer, about 29.15% PE-68 flame retardant additive, about 17.49% tris (3-bromo-2 , 2-bis-

(bromomethyl) propyl) phosphate flame retardant additive, and about 23.33% antimony trioxide flame retardant synergist was prepared by extruding the components in a Haake 19" conical, partially intermeshing, counter rotating, twin screw extruder at an extruder speed of 70 rpm and a melt temperature of 165°C. This master batch contained about 60% of polar flame retardants and flame retardant synergists. Having described the invention, we now claim the following and their equivalents.

Claims

CT.ATMfi What is claimed is :

1. A mater batch for flame and bloom resistant polymers comprising:

(a) a total of at least 25% by weight of one or more additives selected from the group consisting of polar additives, flame retardant synergists, and mixtures thereof; and (b) at least one elastomeric carrier resin; wherein at least one polar additive is a polar flame retardant additive.

2. The master batch of claim 1 in which the elastomeric carrier resin is a substantially linear ethylene/C₃-C₂₀ α-olefin copolymer prepared by constrained geometry catalysis using a metallocene catalyst.

3. The master batch of claim 2 in which the elastomeric carrier resin is a substantially linear ethylene/C₅-C₁₀ α-olefin copolymer.

4. The master batch of claim 3 comprising a tris (trihaloneopentyl) phosphate polar flame retardant.

5. The master batch of claim 4 in which the elastomeric carrier resin is an α-octene/ethylene copolymer.

6. The composition of claim 5 comprising tri (tribromoneopentyϊ) phosphate polar flame retardant.

7. The master batch of claim 6 additionally comprising a flame retardant synergist .

8. The master batch of claim 7 comprising a total of at least 50% by weight of one or more additives.

9. The master batch of claim 1 comprising a total of at least 50% by weight of one or more additives.

10. A method for producing a flame and bloom resistant polymer, the method comprising incorporating into the polymer a master batch for flame and bloom resistant polymers comprising:

(b) at least one elastomeric carrier resin; wherein at least one polar additive is a polar flame retardant additive.

11. The method of claim 10 in which the flame and bloom resistant polymer is a polyolefin.

12. The method of claim 11 in which the polyolefin is selected from the group consisting of polypropylene, propylene/ethylene copolymers, and mixtures thereof.

13. The method of claim 12 the polyolefin comprises about 2 to 5 parts by weight elastomeric carrier resin per 100 parts by weight of the polyolefin.

14. The method of claim 13 in which the polyolefin comprises: 3 to 10% by weight of at least one tris- trihaloneopentyl) phosphate flame retardant; 0.5 to 5% of a co-additive flame retardant selected from the group consisting of tetrabromobisphenol-A-bis (2, 3- dibromopropyl) ether, tetrabromobisphenol-S-bis (2,3- dibromopropyl) ether, and mixtures thereof; and a flame retardant synergist selected from the group consisting of antimony trioxide, antimony pentoxide, zinc stannate, sodium antimonate, zinc hydroxystannate, and zinc borate.