CA1279961C - Granular flame retardant agents, process for their preparation and method and materials obtained thereby - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Granular flame retardant agents are disclosed which incorporate halogenated organic flame-retardant compounds, without any binders. The granular agents may further contain desired additives and organic or inorganic flame-retardant synergistic materials. The granular agents are dust-free and are usefully employed in a method for imparting flame-retardant properties to flamable plastic materials. A
process for the preparation of the granular flame retardant agents of the invention by cold compaction is also described.

Description

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GRANULAR FLAME RETARDANT AGENTS, PROCESS FOR THEIR PREPARATION
AND METHOD AND MATERIALS OBTAINED THEREBY

BACKGROUND OF THE_INVENTION
a) The Field of The Invention The present invention relates to granular flame retardant agents, to a process for preparing the same, to a method for imparting fIame-retardant properties to plastic materials using said agents, and to flame-retarded plastic materials obtained thereby.
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More particularly, the present inventlon refers to the use of halogenated hydrocarhon flame retardant agents, alone or in admixture with organic or inorganic flame-retardant agents , and synergists. -b) The Prior Art It is well known ln the~art to~use halogenated hydrocarbons to impart flame-retardant;(FR~ properties to flammable plastlcs.~Exampl~es~of commercially~available FR;agents are Deoabromod1phenyl~oxide,~Penta-and Octabromodiphenyl oxide, Hexabromocyclododecane and~Tetrabromoblsphenol A. It is - : - : : :

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also known that it is possible to employ mixtures of two or more of such halogenated hydrocarbons, which may be both in solid form or not, and/or mixtures which comprise inorganic or synergistic FR agents, such as Antimony Oxide or Melamine Isocyanurate. Non-solid FR compounds comprise, for instance, Pentabromodiphenyl oxide. Other various additives are also often employed in admixture with the FR composition, such as binders or carriers, lubricants, smoke suppressors, anti-dripping agents, such as DPFA, and thermal stabilizers.

The halogenated FR compositions, however, are usually in fine powder form which presents several problems. Dispersion of the FR compound within the processed plastic is often non :
homogeneous, pollution problems due to dust formation are severe and certain additlves, e.g.,~ antimony oxide, are toxic.
Therefore, several approaches have been tried~in order to avoid dlrect~use of FR compositions in powder form, for ins;tance, by preparing master batches of the plastic containing high concentrations of FR composition; or colloidal suspsnslons of~the~FR compounds sre prepared, which are then mixed~wlth the monomer, or binders are used in order to prep-re agglomerstes of FR oompounds.

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SUMMARY OF THE INVENTION
It has now been found, and this is an object of the present invention, that it is possible to employ relatively large granules sizes (2 - 4 mm), for granules obtained through compaction and grinding, and that the said granules can be obtained without the addition of any binding agent.

It is a further object of the invention to provide a me-thod for imparting flame retardancy to polymers, which eliminates the problem of dus-ting and potential health hazards existing in the methods known in the art.

It has further been found, and this is another object of the invention, that FR plastic material obtained through the use of the granular Fh compositions of the invention do not show : ~

any appreciable difference in their properties, as compared to the material obtained by using~the same FR agent in powder :
form. Furthermore, no~difference in processability of the two different FR formulations (those processed with compacted agents and~those;processed~with powders) is observable, In the normal course of polymer~processing.

The FR compositions and process of the invention obviate :

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many disadvantages of known processes, and further present several other advantages, as will be apparent hereinafter.

The flame-retardant granular compositions according to the invention are characterized in that they contain, in compacted granulated form, one or more halogenated hydrocarbon flame retardant compounds, alone or in admixture with organic or inorganic flame-retardant or flame-retardant synergistic compounds and/or additives. Preferably, the compacted form is a cold-compacted form.

By cold compaction it is meant that no external heat is added during the;compaction operation for the purpose of ~aiding or promoting compaction and that compaction is substantially carried out by~ mechanical pressure. However, as it wlll be apparent to a person skilled in the art, it may be advantageous in some instances to maintain during processing, or during :: :
one or more stages thereof, a temperature higher~than room temperature, e.g., for the pùrpose of promoting removal of volatile materials contained in the solid FR material or mixture.~Thus, f;or~example, DECA~powder may contain some such voIatlle~matters~the~removal of which can be assisted by caus1ng~the temperature~to raise s~llghtly, up to 40-60C. The heatlng of the~FR~material during processing, if eEfected for :

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such purposes, does not substantially alter or affect the process of compaction as herein described, and any process employing such heating for purposes unrelated to the compaction process - and with temperatures which do not affect the mechanical properties of the material to be granulated - does not exceed the scope of the present invention.

The size-distribution of the said granules is preferably comprised between about 2 and about 4 mm. The additives which can be admixed with the FR compound(s) comprlse, e.g., lubricants, thermal stabilizers, non-polymeric binders, smoke suppressors and carriers. Suitable smoke suppressors employed in the art are, e.g., ammonium molibdate, zinc borate and bismut salts.

According to a preferred embodiment~of the invention the halogenated hydrocarbon is selected from among Pentabromodiphenyl e~ther, Octabromodiphenyl ether, Decabromodiphenyl ether, Tetrabromobisphenol A and its derivatives, Tetrabromobisphenol A bis(allylether), Dibromoneopentylglycol,~Tribromoneopentylalcohol, Hexabromocyclododecane, Tribromophenyl allylether, Tetrabromodipentaerythritol, bls(tribromophenoxy)ethane, .

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ethylene bis(dibromonorbornane)dicarboximide, Tetrabromobisphenol S bis(2,3-dibromopropyl)ether, poly(pentabromobenzylacrilate), and Dodecachloropentacyclo-octadeca-7,15-diene, and the inorganic flame-retardant/
synergistic compound is selected from among antimony oxide, magnesium oxide, magnesium hydroxide, ferric oxide, ammonium salts and cyanurate derivatives. A preferred compacted material prepared according to the invention.
has a diametral crushing strength of at least 0.3 kg/sq.cm.. As it will be apparent to a person skilled in the art, the diametral crushing strength is an important parameter in order that a granular material be strong enough so that the granules do not disintegrate during normal handling. As the person skilled in the art will readily appreciate, too high values of the crushing strength may cause difficulties in processing, e.g., due to difflcult disintegration of the granules. In such case, it will be required to adjust this value to the operatlng parameters employed in the process, as it will be apparent to the~man of the art. Thm granules so obtained comprise bromo- or chloro-containing hydrocarbons or mixturms thmreof, alone or in admixture with FR

synergistic compounds such as metal oxides and sulphides, and organic salts of antimony, boron, arsenic and zinc borate.

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The process for preparing a composition according to the invention is characterized by the steps of:
a) feeding the flame-retardant material or mixture to a compacting apparatus;
b) carrying out the compaction of the flame-retardant material or mixture in the compacting apparatus;
c) feeding the resulting compacted material to a granulator;
d) granulatiny the compacted material in the granulator;
e) withdrawing the fraction of the throughput from the granulator, which has the desired size-distribution; and f) optionally recycling the fraction of the granulated material having undesired sizes to the compacting apparatus;

According:to:a preferred embodiment of the:invention, the compacting apparatus is a~roll~compactor. According to another preferred embodiment of the invention the granulator ~ ;
is a screen:~granulator. ~ : :

Granulated~flame retardant:compositions, whenever prepared~
by the process of:the invention, also form part of the present invention~

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The process~for producing flame-retarded articles according , to the~invention~ s characterized in~that the material to ~ :

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which it is desired to impart flame-retardant properties is mixed during processing thereof with a granular composition according to the invention. Flame-retarded articles, whenever produced by the said process, also form part of the present invention.

A good distribution of a powder in the polymer is very difficult to obtain. Thus, the advantage of using granular material which, apart from the aforesaid advantages, i9 also more easily dispersed in the polymer, is an important feature of the invention. Since plastic processing apparatuses usually comprise nozzles, the problem of clogging thereof must be overcome. For this purpose, the art has employed very small powder sizes, or colloidal suspenslons of FR ma-terial, in order to avoid such clogging and size problems.~The granules of the invention, however, can be employeù with large sizes such as 2 - 4 mm, since the FR material dispersed in the polymer melts together with the polymer itself or disintegrates thereln, and is therefore fine]y distrlbuted therein. When granules contain material which does not melt at the polymer process1ng~temperature/ such as antimony oxide or~DECA, care must be taken to obtain a fine distributlon of~such materlals wlthin the FR granules/ so that when the;granùles melt or dlsintegrate they wlll be liberated :~ : : : :

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in fine powder form and homogeneously dispersed in the polymer. It should be noted that when pulverized material is employed homogeneous dispersion thereof in the polymer is hindered also by the formation of agglomerates of the FR
material, which is avoided when operating according to the invention.

Another advantage of the invention ls that it is possible to obtain FR agents having a bulk density much higher than that of the corresponding powdered composition. As it will be apparent to a person skilled in the art, this fact is advantageous both for shipping and storage purposes, and because it requires that smaller volumes of FR agent be processed, as compared to powdered agents.~ Table I below shows values for three~different composition Decabromodlphenyl ether (DECA) alone, Deca in admixture with antimony oxide with a DECAjAO ratio of 3:1, and ~
poly(pentabromobenzy1acrllate~) (PBB-PA). i~t can be seen that the bulk density of DECA and DECA/AO mixtures~is : : , considerably increased by~compaction, while it remains :
unchanged for PBB-PA. ~

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Table I

Bulk Density (g/cm3) MATERIAL Powder Compacted .

DECA 1.043 1.583 DECA/AO (3:1) 1.107 1.694 PBB-PA 1.249 1.249 While the bulk density is not a parameter having an absolute value inasmuch as it is somewhat;dependent on the method by which the sample has been prepared, such~variations are not too great and the above data are indicative of the change in bulk density due to compaction granulation.
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The ratio between the~halo-contalning~oompound and the~
synergistlc~compound will depend on the stability:of the halo compound~`and~the~reactivlty of the particular synergist empl~oyed as~well~as~the~plastlc material employed. Generally this ratio can~va~ry~ln a~broad range such as between:95 parts : ~:~
synergistic~ compound to~5 parts halo-compound and 5 parts :~ ~
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symergistic compound to 90 parts halo compound.

In addition to the main advantage that the compositions and method of the present invention are free from dusting, the effective content of flame retardant compositions is very high, since the granules of the invention are substantially free from carriers and binding materials.

The above and other characteristics and advantages of the invention will be better understood through the following illustrative and non-limitative examples.

DETAILED DESCRIPTION OF PREFERREV EMBODIMENTS

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~ Example 1 Compaction and Diametral Crushing~Strenqth Experiments were carried out at ambient temperature for ~ :
testing the~characteristics~of the compaction of different FR/synerglst;formulations, utilizlng the diametral :
compression test~(as described in;Materials Research~&

Standards, April 1963,~pp. 283-284) for the measurement of :, :
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tensile strength. The apparatus consisted of a circular cylindrical specimen, which is compressed diametrically between two flat plates. The maximal tensile stresses develop normally to the loading direction across the loaded diameter, and are proportional to the applied load. Loading produces a biaxial stress distribution within the specimen.
The maximal tensile stress that acts across the loaded diameter is represented by the following formula:

TS = 2P
~IDt wherein: TS is the maximal tensile strength; P is the applied load; D is the specimen diameter and t is the thickness of the specimen.

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This method of testing enables to determine substantially only the tenslle strength, rather than~shear or compressive failures. In the diametral-compression specimen, the amount of material subjected to stress is~proportional to both the length and dlameter. ~It~has been found that antimony axide alone cannot be compressed to a compacted form, without the aid of additives,~by using pressures as high as 500 - 2000 Kg/sq. cm. By ~incorporating~an organic flame retardant material,~in~;amounts rang1ng~from 10% to 90~, it was :: :

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surprisingly found that strong granules containing antimony oxide can be obtained, whose diametral crushing strength is higher than 0.3 Kg/sq. cm. Table II below summarizes the results for the diametral crushing strength (DCS) of granules obtained from mixtures of antimony oxide (AO) with two fire-retardant compounds, ~iæ., DECA and Tetrabromobisphenol A (TBBA).

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Table II
Specimen Composition Run : Pressure DCS
No. wt% AO( ) wt% DECA ~2) wt~ TBBA(3)applied(kq) kq/cm2 1 90 - 10 2000 3.8 2 75 - :: 25 2000 2.8 3 75 25 : - 2000 0.6 4 50 50 ~ - 2000 1 2 50 -~ ~ 50 : 2000 8 6 6 25 37.5 37.5 2000 4.4:
7 25 75: - : 1000 0.9 . .. :~ , . ~ ~
(1) Antimony Oxide~produced By Anzon (Timonox White Startm) (2~ DECA Produced by~Bromine Compounds Limited (3) TBBA Produced by Bromine Compounds Limited From the above table it can be seen that it is possible to obtaln hlgh:dlametral crushing strengths, and:further that the value~:of~the:DCS~can~be tallored to the desired requirements by controlling the~composltion of the FR agent~produced and :
the pressure~employed. ~ : ~

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The following examples illustrate the preparation of granular FR compositions. In all compaction experiments, a CS-25 compactor model (Bepex* Germany) was employed, unless otherwise indicated. In all experiments the hydraulic pressure was 40 bar, the pressure of the accumulator was alsa 40 bar and the pressure force was 70 kN. In all examples compaction is obtained in the absence of a binding agent.

Example 2 800 g of Octabromodlphenyl ether (OCTA) were fed through a screw feeder to the CS-25 compactor, using a roll speed of 7 :
rpm. The compacted material leaving the compactor, in the form of briquettes, was~fed;to~a screen granul~ator which broke the briquettes produced by the compactor. The screen placed at the bottom o~f the~granulator permitted to obtain the :: :
separation of the granules having the desired size-distribution, while granules having smaller size-distributions~were recycled to the compactor. 57~ of the throughput of the~granulator was found~to have the desired size-dlstribution ~(2 - 4 mm),;and 43% thereof~was recycled to the compactor;.
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Example 3 Operating as in Example 2, but using a mixture of 75~ OCTA
and 25% Antimony Oxi~e, it was chosen to produce granules having a size-distribution of 2 - 3 mm. 30% of the material leaving the granulator was found to have the desired size-distribution, and the rest was recycled to the compactor.
As it will be apparent to the man of the art, restriction of the Fange of sizes of the product results in a much higher recycle ratio, as expected.

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Example 4 Example 3 was repeated, but~usi~ng pure DECA as the material to be granulated, and with a;roll~speed of 5 rpm. The results obtained were~as~in Example 3.

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~ ~ Example 5 Example~2 was repeated,~ but using a mixture oE 75% DECA and 25% AO.~;~About~ 50~ of~a product, having a required -:

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size-distribution of 2 - 4 mm, was recovered from the granulator.

Example 6 Example 3 was repeated, using PBB-PA as the material to be granulated, and with a roller speed of 12.5 rpm. About 30% of the throughput was recovered as granulated material having the desired size-distribution of 2 - 3 mmj and the rest was recycled to the compactor~

Example 7~

Example 6 was repeated, using a mixture of 73.1% PBB-PA, 24.4~ S~O3 and 2.5% of Calclum Stearate. The results obtained were comparable to those of Example 6.

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Example 6 was~repeated, but using Hexabromocyclododecane (HBCD)~as the materla:l to be granulated. 25% of the material having~the~desired~size-di~strlbution of 2 - 3 mm was :

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recovered from the granulator, and the remaining fractions were recycled to the compactor.

Example 9 Example 2 was repeated, but using a L 200/50 P compactor (Bepex), with a pressure force of 40 kN, and a mixture of 77%
HBCD, 19.3% Tribromophenyl allyl ether and 3.7% lubricants and heat stabilizers. 54~ of the throughput o the granulator was found to have the desired size-distribution (2 - 4 mm).
~: ' The followlng examples illustra~te;the~preparatlon of flame retarded~polymerlo;materlals, uslng~the composltions according to the invent~ion and compositions known in the art.

~ Example 10 Three~dlfferenb~runs~were~carried~out, to prepare flame retarded~Hlgh~Impact~Polystyrene;;(HIPS), using~as the FR
~;agent~ three~different~compo~s1tions:;DECA in powder form, ::: :: : ~ :

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DECA in granulated (compacted) form, obtained in Example 4, and a mixture of 75~ DECA and 25% A0, in compacted form (granules), obtained in Example 5. In all cases, care was taken to obtain a product having an identical total Br content of 10~. ' The granules (and the DECA powder) were in each case thoroughly mixed with the HIPS (Galiren*Q 88-5, produced by Israel Petrochemical Enterprises) by dry mixing, and then fed into a Buss Xneader RR*46 type extruder (Buss Ltd., Switzerland) at a processing temperature of 160-190C.
Specimens were prepared by injection moulding at 210-230C, with an injection moulder machine of the type Allrounder-221-75-350 (Arburg). The FR HIPS so obtained was tested in~each case for :ltS FR and general properties, and the results of these tests are summarized in Table III.
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Table !IL

FORMULATIONS Test No 1 Test No.2 Test No.

Components~
Hl PS . 83 83 83 Tinuvin*P (") o 5 0 5 0.5 Tinuvin*770( ) 0.5 0.5 0.5 DECA (powder) 12.0 DECA (compacted) -- 12.0 --DECA(75æ)~AO(25~)~compacted) -- -- 16.0 Br content l 0.0 10.0 10.0 Properties UL-94 rating V-O V-O V-O
Flaming time, sec 0 8 4 LOI~ 23.7 ~2.3: 23.6 HDT ~C (264 psi) 63.8 65.4 : 63.4 Izod notched impact, J/m q9 6~ 57 Tensile Impact, kJ/m2 62 69 64 Elongation at break, % ` 25.5 -- 19 U.V. stability (~DE, 24h) : ~ 36.5 : -- 37.5 ._ ~") U.V. stabi~lizers (Ciba-Geigy~AG) ~: :
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Example 11 Three different runs were carried out, to prepare flame retarded poly(butyleneterephtalate) (PBT), using as the FR
agent three different compositions: PBB-PA in powder form, PBB-PA in granulated (compacted) form, obtained in Example 6 (composition I), and a mixture of 73.1% PBB-PA, 24.4% AO
and 2.5 Calcium Stearatej ln compacted form (granules), obtained in Example 7 (composition II).

The FR agent was in each case throughly mixed with the PBT, and processed as in Example 10. The processing temperature was 260-275C and the:temperature o~ injection was 240-250C. The results of these tests are summarized in Table IV below.

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TableIV
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FORMULATiONS non compacted compacted compacted (comp. I) (comp. I l) Com~onentsY
PBT GFR
Arnite*TV4-261(~) 87 87 87 Calcium Stearate(CS) I 1 --A.O. white star ~ 4 4 --PBB-PA (compacted) -- 8 PPB-PA~AO~CS -- -- 13 Flamability LQI 2g.2 29.5 29 4 UL-94, 1.6mm VO VO VO
HDT-C ~ 191.7 198.2 198 I mpact I zod, Notched (J/m) 82.7 69.4 75.0 :, Tensi !e ProDerties: :
Maximal Strengthj MPa 102.3 ~ 101.0 Yleld strength, MPag2.6 82.3 90.0 Elongationat-break, %2.6 ~ 2.7 2.5 MO~ULUS,Mpa 6900 6670 6800 Shore Hardness 75.5 75.5 75.2 .:
(*) Glass-fiber reinforced containing 30æ glass fibers (Akzo) ~"'I) Timonox*White Star (Anzon) * Trade~ mark : ~

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The data reported in the above tables have been obtained according to the following standard tests.
- Melt f low index: flow rates by extrusion plastometer (ASTM D 1238-79), on an extrusion plastometer Tinius Olsen Model Ve 4-78.
- Flammability: UL-94 vertical burning test in a flammability hood (acoording to UL); and Limiting oxygen index (LOI) (ASTM
D 2863-77) on a FTA Flammability Unit Stanton Redcroft.
- Tensile yield strength; Elonqation at break at yield and Modulus: (ASTM D 638-82) on a Zwick 1435 material testinq machine.
- Izod notched~ ASTM D 256-81) on a Pendulum impact tester type 5102 Zwick.
- Tensile_impact enerqy: (ASTM D 1822-79) on a Pendulum impact tester type 5102 Zwick.
- HDT: Deflection temperature under flexural load (18.5 kgicm2) (ASTM b 648-72) on a CEAST 6055.
- U.V. StabilitY: Accelerated weathering test - irradiation ~or 250 hrs and measuring of the color change by color deviation, on an Accelerated Weathering Tester Q-U-V ¦B-lamps), (The Q-Panel Co.
- Color Deviation: Color~measurement and comparison with reference~speoimen,~on~a Spectro Color Meter SCM-90, (Techno-Instruments Ltd.).

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The above exa~ples and description have been given for the purpose of illustration, and are not intended to be limitative.
Many variations can be effected in the various co~positions, methods and processes, without exceeding the scop~ of the invention.

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Claims (27)

1. A cold compacted flame-retardant granular composition comprising one or more halogenated hydrocarbon flame retardant compounds, said granular composition comprising compacted powder particulars substantially free of a binder, whereby a granular composition is provided which is substantially free of material which does not possess flame-retardant properties.

2. The composition according to claim 1 whereby said granular composition has a particle size between about 2 and about 4 mm.

3. The composition according to claim 2 further including an added component comprising organic or inorganic flame-retardant or flame-retardant synergistic compounds or additives.

4. The composition according to claim 3, wherein said added component comprises up to about 90% of antimony oxide.

5. The composition according to claim 2 having a diametral crushing strength of at least 0.3 Kg/sq. cm.

6. The composition according to claim 3, wherein said added component comprises an additive selected from the group consisting of lubricants, thermal stabilizers, smoke-suppressors, anti-dripping agents and carriers.

7. The composition according to claim 6, wherein the halogenated hydrocarbon is selected from the group consisting of pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A and its derivatives, tetra bromobis-phenol A bis(allylether), dibromopentylglycol, tribromopentyl-alcohol, hexabromocyolododecane, tribromophenyl allylether, tetra-bromodipentaerythritol, bis(tribromophenoxy)ethane, ethylene bis(dibromonorborane)dicarboximide, tetrabromobisphenol S bis(2,3-dibromopropyl)ether,and dodecachloropentacyclooctadeca-7,15-diene.

8. The composition according to claim 7, wherein said added component comprises a compound selected from the group consisting of antimony oxide, magnesium oxide, magnesium hydroxide, ferric oxide, ammonium salts and cyanurate derivatives.

9. A cold-compacted flame-retardant granular composition having a diametral crushing strength greater than about 0.3 kg./sq.cm, comprising a compacted powder substantially free of a binder, which powder comprises one or more halogenated hydrocarbon flame-retardant compounds, whereby a granular composition is provided which is substantially free of material which does not possess flame-retardant properties.

10. The composition according to claim 9, having a particle size up to about 4 mm.

11. The composition according to claim 10, having a particle size of between about 2 and 4 mm.

12. The composition according to claim 9 further including an added component comprising organic or inorganic flame-retardant or flame-retardant synergistic compounds or additives.

13. A process for preparing a composition characterized by the steps of:
a) feeding a flame-retardant material or mixture comprising one or more halogenated hydrocarbon flame retardant compounds to a compacting apparatus;
b) carrying out a cold-compaction of the flame-retardant material or mixture in the compacting apparatus;
c) feeding the resulting compacted material to a granulator;
d) granulating the compacted material in the granulator;
e) withdrawing the fraction of the throughput from the granulator, which has the desired size-distribution; and f) optionally recycling the fraction of the granulated material having undesired sizes to the compacting apparatus.

14. The process of claim 13, wherein the compacting apparatus is a roll compactor.

15. The process of claim 13, wherein the granulator is a screen granulator.

16. A granulated flame retardant composition prepared by the process of any one of claims 13, 14 or 15.

17. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 2.

18. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 3.

19. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 4.

20. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 5.

21. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 6.

22. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 7.

23. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 8.

24. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 9.

25. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 10.

26. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 11.

27. A process for producing flame-retarded articles, characterized in that the material to which it is desired to impart flame-retardant properties is mixed during processing thereof with a composition according to claim 12.